Powder Metallurgy Review Spring 2021 Vol 10 No 1

POWDER METALLURGY

VOL. 10 NO. 1 VOL. SPRING 2021 REVIEW

TECHNICAL TRENDS IN METAL-CUTTING TOOLS THE CHALLENGES OF FATIGUE ASSESSMENT CUTTING GREENHOUSE GAS EMISSIONS IN PM

Published by Inovar Communications Ltd www.pm-review.com Publisher & Editorial Offices Inovar Communications Ltd POWDER 11 Park Plaza Battlefield Enterprise Park Shrewsbury SY1 3AF METALLURGY United Kingdom Tel: +44 1743 211991 www.pm-review.com REVIEW

Managing Director Nick Williams [email protected] News Editor Paul Whittaker [email protected] Features Editor Emily-Jo Hopson-VandenBos Adaptation is the key [email protected] Assistant Editor It has been over a year since the coronavirus (COVID-19) Kim Hayes pandemic brought industry to a halt in the majority of the devel- [email protected] oped world. In the months since, many manufacturing industries Consulting Editor have come back to life at a faster pace than first expected, but Dr David Whittaker Consultant, Wolverhampton, UK all still face the challenges of a significantly changed economic landscape. DISCOVER THE AMAZING NEW Advertising Sales Director Jon Craxford Tel: +44 (0) 207 1939 749 Whilst the progress of the PM industry over recent decades has [email protected] been a story of evolution rather than revolution, it has shown Production itself to be an industry that has the flexibility to adapt to changing ULTRASONIC ATOMIZER Hugo Ribeiro, Production Manager [email protected] market requirements. In this issue, Bernard North reflects on how the development and production of metal-cutting tools, one SOLUTION FOR SMALL POWDER BATCHES! Subscriptions Jo Sheffield of the largest markets for PM technology, continues to meet the [email protected] needs of new market trends (p. 47). ● SPHERICAL POWDER WITHOUT ANY SATELLITES Accuracy of contents Whilst every effort has been made to The PM industry is also responding to evolving global issues ● 2 ensure the accuracy of the information in around climate change and environmental protection. Oster- VERY ECONOMIC MACHINE SOLUTION ON 2m SPACE, this publication, the publisher accepts no POWERED BY ULTRASONIC TECHNOLOGY, LOW RUNNING COSTS responsibility for errors or omissions or walder AG analyses the benefits of a powder press design that for any consequences arising there from. significantly reduces greenhouse gas emissions p.( 83), and the ● Inovar Communications Ltd cannot be held EU’s NEWMAN project overviews its progress and future roadmap A DESIGN FOR EASY HANDLING & CLEANING, QUICK ALLOY responsible for views or claims expressed CHANGE WITH MINIMUM CROSS CONTAMINATION by contributors or advertisers, which are not as it seeks to minimise the use of nickel in ferrous PM (p. 89). AUS 500 necessarily those of the publisher. Reproduction, storage and usage Change is also afoot at PM Review, as our team continues to Single photocopies of articles may be made develop along with the needs of our readers. This marks my first CUSTOM ALLOY POWDER WITHIN 1 HOUR for personal use in accordance with national issue as Features Editor, a role in which I hope I will continue copyright laws. Permission of the publisher IN JUST 4 EASY STEPS and payment of fees may be required for all to promote our industry with as much dedication as my prede- other photocopying. cessor, Paul Whittaker. Paul, in a new role as Group News Editor, All rights reserved. Except as outlined will focus his efforts on expanding our news coverage across all above, no part of this publication may be Inovar titles. reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, photocopying or otherwise, With vaccination efforts well underway, it feels for the first time without prior permission of the publisher as though the end to this pandemic is in sight. With the ever- and copyright owner. 1 PREPARE YOUR MATERIAL 2 HEAT IT 3 ATOMIZE 4 ENJOY changing landscape of manufacturing, and uncertainty in PM’s Submitting news and articles markets, the future still holds a number of challenges – but what IN ANY SHAPE OR FORM – UNDER CONTROLLABLE IN SMALL BATCHES DOWN TO YOUR OWN EXTREMELY We welcome contributions from both industry and academia and are always is clear is that PM is an industry that is capable of evolving and IT ONLY NEEDS TO FIT INTO ATMOSPHERE OR UNDER 100G OR UP TO SEVERAL KG/H SPHERICAL POWDER WITHOUT interested to hear about company news, CRUCIBLE VACUUM (FOR BRONZE) ANY SATELLITES adapting to changing markets and applications. innovative applications for PM, research and more. Emily-Jo Hopson-VandenBos Subscriptions Features Editor, Powder Metallurgy Review DISCOVER our ULTRASONIC ATOMIZER, our WATER ATOMIZER and our GAS ATOMIZER solutions Powder Metallurgy Review is published on a quarterly basis. It is available as a free on www.bluepower-casting.com electronic publication or as a paid print subscription. The annual subscription charge is £125.00 including shipping. Design and production Inovar Communications Ltd. ISSN 2050-9693 (Print edition) Cover image ISSN 2050-9707 (Online edition) Grinding operation on © 2021 Inovar Communications Ltd. a solid carbide tool This magazine is also available for free download from www.pm-review.com (Courtesy Rollomatic)

Contents

47 Technical trends in metal-cutting tools: 83 Reducing CO2 emissions An overview of ongoing innovation in one of PM’s in the PM industry: key markets A lifecycle analysis of Cutting tools for applications in metal processing represent servo-electric versus one of the primary markets for the Powder Metallurgy hydraulic powder industry. Here, PM technology makes it possible to produce presses cutting tools with complex geometries to near-net shape, There is a global need a feat not possible using conventional manufacturing for action to minimise methods. Despite the basic technologies of metal-cutting greenhouse gas emissions tools having existed for several decades, tool manufacturers and, thus, limit further continue to introduce new products which can provide global warming. Despite its substantial benefits. In this article, Bernard North, North reputation as a technology Technical Management, LLC, overviews developments in Rio Tinto Metal Powders’ Commitment Powder metallurgy is a Green Technology, a near net-shape which is already greener than materials, design and software that are driving innovation in to Sustainable Development process that allows for efficient use of raw materials. Rio Tinto most, this also holds true Metal Powders (RTMP) produces iron and steel powders for this important sector of PM. >>> in the Powder Metallurgy The world is getting smaller. The pandemic has made it painfully the industry using carbon-free hydroelectric power generated industry. In recent years, clear how globally interconnected we truly are. We share one in the Province of Quebec, Canada. The primary market for our PM companies have found planet and we all need to ensure that our actions today support powder products is the automotive industry, which is moving 57 Fatigue data for PM steels: How the world’s the generations of tomorrow. At Rio Tinto, the safety of our themselves under increasing increasingly to electrification and away from internal combustion largest PM part producer is facing the challenges people is the Number One Priority. We also apply our core values engines. RTMP is contributing to the development of new powder pressure to improve process to the communities in which we operate, to reduce the impact of of data generation and organisation materials for electric components, from pump assemblies to sustainability, from their our operations on our neighbors. small electric motors in e-bikes and EV’s to create a Greener Data on the material properties of Powder Metallurgy customers as well as Rio Tinto is committed to sustainable development in metals Future Together. steels, in particular static and cyclic strength data, is regulators. processing. This pledge has been recently demonstrated through crucial for end-users to have confidence in the production investments in the world’s first low carbon Aluminum processing At Rio Tinto, we produce materials essential to human progress. technology, Elysis, and in exploring low carbon steel processing For more information about Rio Tinto’s polices, programs, of highly loaded applications. Access to such data also This pressure is only likely to technologies. Rio Tinto will invest $1 billion over the next 5 years and commitment to sustainable development please visit the enables the effective use of commercial fatigue simulation increase in the near future. to help achieve its Net Zero Emissions goal by 2050. Rio Tinto home page at www.riotinto.com software. GKN Sinter Metals, the world’s largest producer Michael Looser and Michael of structural PM components, has grappled with the Sollberger, of Switzerland’s multiple challenges associated with generating, storing and Osterwalder AG, explain how retrieving such data. Markus Schneider, Robert Maassen, the company’s servo-electric Dennis Wawoczny and Christos Radis, GKN Sinter Metals powder presses help make Engineering GmbH, Radevormwald, Germany, share their PM even more efficient. >>> insight into this ongoing effort, which could offer significant Metal Powders opportunities for the wider use of PM. >>> ISO 9001 IATF 16949 www.qmp-powders.com 4 Powder Metallurgy Review Spring 2021 © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd Spring 2021 Powder Metallurgy Review 5 | contents | news | advertisers | events | website | e-newsletter |

+function 89 Nickel-free steel powders: Paving +design GF Machining Solutions the way for sustainable Powder Metallurgy Few sectors of industry remain untouched by the demands of sustainability. The System 3R response to climate change has ramped up considerably in most countries, with Tooling for Powder consumers and regulators alike looking for greater assurance that products have Compacting Technology the lowest environmental impact possible, across the value chain. PM is no exception, and increasing numbers of PM projects on + Simple, quick set-up sustainability have emerged to meet this + High accuracy need. The EU’s NEWMAN project is one such + Low scrape rate effort, seeking to drastically improve PM’s + Maximal machine utilization sustainability by minimising nickel content in + Increased productivity steel powders. Here, the NEWMAN partners discuss the project’s goals, progress and roadmap to completion. >>>

99 Euro PM2020: PM functional Highest precision materials in energy management and & productivity magnetic applications Within the programme of the well-received Highly accurate Euro PM2020 Virtual Congress, held October force control 5–7, 2020, and organised by the European Powder Metallurgy Association (EPMA), technical sessions showcased the latest studies on the high-temperature properties, Encapsulated pressing zone corrosion and wear performance of hardmetals produced by Powder Metallurgy. In this article, Dr David Whittaker provides a summary of each paper presented during this Perfect accessibility

Illustrations may include options. Illustrations session, highlighting the key findings. >>>

IoT ready

Regular features... EP16 ULTRA digital 09 Industry news >>> 112 Advertisers’ index & buyer’s guide >>> GFMS, System 3R Int’l AB, Sorterargatan 1, S-162 50 Vällingby, Sweden, It´s your choice! Fixed die or withdrawal method e-mail: [email protected], www.system3r.com 114 Industry events >>>

Toindustry submit news for inclusion in Powder Metallurgy Review contact Paulnews Whittaker, [email protected]

tion electric vehicle to be launched Amsted Automotive Group formed in 2021. This device uses clutching from Burgess-Norton and Means technology developed by Means and Burgess-Norton proprietary Powder Industries to focus on electric Metallurgy forming. With AAG, the vehicle systems teams’ further integration may allow for more rapid, streamlined Designer and manufacturer of indus- supply, while capitalising on the brainstorming, development and trial solutions Amsted Industries, remaining opportunities for supply refinement of ideas, prototyping and Chicago, Illinois, USA, has brought to traditional internal combustion manufacturing. two of its Tier 1 automotive supply engine programmes.” “The electric vehicle market is business units, Means Industries This combination of experience in no longer emerging. It is here, and and Burgess-Norton, together to torque transfer and powder-metal production volumes will increase form a new technology team: Amsted forming is expected to strengthen rapidly,” commented Jeremy Holt, Automotive Group (AAG). The move component developments, aiming president of AAG. “The forma- combines the groups’ advanced to reduce parasitic losses in the tion of AAG aligns our design and metal forming, Powder Metallurgy, powertrain. This could, potentially, engineering expertise, making and electro-mechanical torque extend the driving ranges of electric the company a leader in torque transfer and propulsion system vehicles and reduce electric motor transfer for electric vehicles without design capabilities. and battery requirements. diminishing resources for internal- The integration is set to provide The advantage of AAG’s formation combustion engine programmes.” an expanded global presence, with became apparent to the company www.meansindustries.com sixteen facilities throughout North during development of a discon- www.burgessnorton.com America, Asia and Europe to better nect device used in a new produc- www.amsted.com serve the company’s customer base with a robust manufacturing footprint producing over 100 million components and assemblies annually. It is expected to position AAG as a vertically integrated leader of electri- fied propulsion solutions for global transportation systems. “The world automotive market is going through a period of fundamental change,” stated Stephen Smith, chairman, president and CEO, Amsted Industries. “The transition to electric vehicles has the potential to reshape much of the industry, including the supply base. We are bringing Means Industries and Burgess-Norton together to form the AAG to focus on being significant The Amsted Automotive Group will combine advanced metal forming, Powder participants in electric vehicle tech- Metallurgy, and electro-mechanical torque transfer and propulsion system nology, design and manufacturing design capabilities (Courtesy Burgess-Norton)

Plansee Group becomes majority Miba creates shareholder in Ceratizit Group Executive

Austria’s Plansee Group has “We want to continue Ceratizit’s Committee, plans reported that, as of March 1, 2021, success story more quickly and more new corporate it holds the majority interest in the effectively, by being the majority carbide tool production company shareholder,” stated Karlheinz Wex, strategy Ceratizit SA, headquartered in spokesman of the Plansee Group Miba AG, Laakirchen, Austria, has Mamer, Luxembourg. Formed in executive board. “Our objective is announced it will create an Executive 2002 as the result of a merger to create a fully integrated corpo- Committee, as it seeks to develop between Plansee Tizit and Ceram- rate group for the production and and implement its new corporate etal, Plansee Group’s share in processing of molybdenum and strategy, Miba 100, for the period up Ceratizit initially accounted for 50%. tungsten materials.” to the company’s 100th anniversary in The parties have agreed to keep Wex sees potential for synergies in 2027. The new Executive Committee the extent of the acquired interest the supply of tungsten raw material, will serve as the highest opera- and any financial details confiden- in close cooperation on digitalisa- tional management body within tial, although it is reported to be tion projects and in service func- the company and its members will the largest transaction in Plansee’s tions. Some essential elements in be current Miba board members F history. It was added that Plansee this process have been outlined, with Peter Mitterbauer, Markus Hofer Group holds options to acquire the further integration of Plansee High and Martin Liebl; as well as Chris- remaining stake in Ceratizit in the Performance Materials (products toph Ederer, who will be responsible coming years. made of molybdenum and tungsten for the company’s Bearing division Since its inception, Ceratizit’s metals) and Ceratizit (tungsten following Wolfgang Litzlbauer’s sales volume has tripled and the carbide tools) and the future safe- departure in July; Bernd Badurek, company has evolved into a leading guarding of the raw materials supply. who will take over responsibility for company within the hard metal www.plansee.com the company’s Sinter division when industry. www.ceratizit.com Harald Neubert retires in February; and Bernhard Reisner, its HR director. Sacmi adds MPH150 to range of metal With the new Miba 100 strategy, the company stated that it primarily powder presses seeks to determine how it wants to use the trends of decarbonisa- Sacmi, based in Imola, Italy, has equipped with the API (Assisted tion and digitisation and grow in the expanded its range of metal powder Programming Interface), a system process. The consequences of the presses with the new MPH150, a CNC that drastically reduces the program- coronavirus (COVID-19) pandemic hydraulic press equipped with three ming and setup times of the press. for society, markets and tech- upper and three lower auxiliary axes What sets this new press apart, nologies are also being taken into and a pressing force of 150 tons. states Sacmi, is the absence of a account. Meanwhile, the company’s Like all Sacmi metal powder foundation pit, resulting in a more corporate mission, ‘Technologies for presses, the MPH150 will be compact machine with a reduced a cleaner planet’, will continue to be footprint. The press also features the driving force of its strategy. heightened speed, which allows an No changes are planned for Technology Leaders in Aluminum, Copper increase in productivity up to 50% Miba’s individual divisions and without the loss of precision and locations and their employees and TitaniumGlobal for TA edLeaderscdhitniovelo Mingya Aluminum, nLuefaacdtuerisn giCoppern Alu mandin um, Copper reliability. through the implementation of the The new press was reportedly Executive Committee. The new Titaniumand for Ti tAdditiveanium fManufacturingor Additive andMan ufacturing developed in response to evolving structure is expected, however, to market demands and specific provide a number of advantages PowderTechn oMetallurgylogy Leaders in Aluminum, Copper customer requests for a machine such as closer proximity to markets, with higher performance capabilities, customers and technologies, and and Titanium for Additive Manufacturing flexibility and efficiency. The MPH150 flatter hierarchies. Miba believes www.kymerainternational.com was the result of numerous tech- that this will make it possible to take nical developments by the company, advantage of future opportunities to further the scope of its already- faster, with greater agility and to The new MPH150 offers improved existing PM compacting presses. greater success. productivity (Courtesy Sacmi) www.sacmi.it Globawww.miba.coml L eaders in Aluminum, Copper and 10 Powder Metallurgy Review Spring 2021 Tita©n 2021 Inovariu Communicationsm Ltdfor Add© 2021i Inovarti Communicationsve LtdManufactuSpringr 2021in gPowder Metallurgy Review 11 and Po2020w Kymerad Summere advert PMR.inddr 1Metallurgy 09/06/2020 11:14:54 Industry News | contents | news | advertisers | events | website | e-newsletter | | contents | news | advertisers | events | website | e-newsletter | Industry News

Ametek announces fourth quarter $79.8 million and operating income margins were 21%, up 110 basis Sandvik completes and full year 2020 results points versus the same period last acquisition of Miranda Tools year. Ametek, Inc, Berwyn, Pennsylvania, sales and order improvements in the “EMG also delivered strong Sweden’s Sandvik AB has completed the previously USA, has released its financial results quarter despite the ongoing impacts operating results in the quarter,” announced acquisition of the entire business of India- for the fourth quarter and full year of the COVID-19 pandemic. Further- noted Zapico. “As EMG’s topline was based Miranda Tools, a manufacturer of High-Speed ending December 31, 2020. Full year more, we delivered record operating negatively impacted by the divesti- Steel and solid carbide round tools. 2020 net sales were $4.5 billion, down results and substantial margin ture of Reading Alloys and weaker The Miranda Tools’ business will be part of Sandvik from $5.1 billion in 2019. Operating expansion in the fourth quarter, with demand due to the global pandemic, Machining Solutions’ division Dormer Pramet, within the income for the year was $1.03 billion, EBITDA margins a robust 30.1%.” EMG drove impressive operating business area Sandvik Manufacturing and Machining down from $1.18 billion in 2019. Net “Additionally, our operational margin expansion through our cost Solutions. In 2019, Miranda Tools reported revenues income for 2020 was up slightly on strength resulted in record levels of and asset management initiatives.” of approximately 200 million SEK with around 580 THE GLOBAL HYDROGEN SOURCE 2019, reported to be $872 million cash flow in the fourth quarter with “This last year presented unprec- employees. The deal is said to have a limited impact on compared to $861 million in 2019. operating cash flow up 13% to $386 edented challenges, both personally Sandvik’s earnings per share. ON-SITE GAS GENERATION SYSTEM The company’s Q4 2020 sales were million and free cash flow up 16% to and professionally, for everyone The acquisition is expected to enhance Dormer COST-EFFECTIVE AND RELIABLE SUPPLY $1.2 billion, an 8% decline compared $349 million representing 158% of at Ametek,” Zapico added. “Our Pramet’s product offering and facilitate an improved to Q4 2019. Operating income in the net income, further strengthening employees stepped up to these chal- presence in key markets such as India, China and South- quarter was $298.1 million, up slightly our balance sheet and liquidity posi- lenges and our businesses delivered east Asia. versus last year’s fourth quarter and tion.” results that consistently exceeded With HyGear’s cu�ng-edge www.home.sandvik operating margins were reported to The Electromechanical Group our expectations.” technology, we provide highly www.mirandatools.in eﬃcient hydrogen generation and be a record 24.9%. (EMG), which incorporates the “For the first quarter of 2021, recycling systems customized to “Ametek completed a challenging company’s specialty metals division, overall sales are expected to be match your needs for your glass year with an excellent fourth quarter,” reported sales in the fourth quarter down low to mid-single digits manufacturing process. stated David A Zapico, Ametek of $379.5 million, down 11% from compared to the same period last ti Chairman and Chief Executive Officer. the same quarter in 2019. EMG’s year,” concluded Zapico. We combine on-site genera on Gasbarre Thermal Processing with our own ﬂeet of trailers to “We continued to see solid sequential fourth quarter operating income was www.ametek.com Systems opens technical guarantee the reliability of supply while reducing the environmental centre in Michigan impact. Our approach is unique because Gasbarre Thermal Processing Systems, headquar- of our strong technology tered in DuBois, Pennsylvania, USA, has announced backbone and the way we Huacheng Moulding (Changshu)Professional Co., Tooling Ltd. Maker the opening of a 715 m2 (7,700 ft2) technical centre in partner with you as our customer. for POWDER METALLURGY since 1978 Livonia, Michigan, USA. Alongside locations in St Marys, Pennsylvania and Cranston, Rhode Island, this technical centre is said to be another step towards Gasbarre OUR PROMISE better positioning themselves to support its customers whilst advancing its product offering. The technical centre will house sales, engineering and service personnel, achieving a core initiative to have qualified personnel to support the large customer base in the American Midwest region. Gasbarre is currently in

the process of installing both atmosphere and vacuum COST SAVINGS RELIABLE SUPPLY INCREASED processing equipment in the technical centre to support SAFETY product development, customer trials and demonstra- tions. “The opening of the technical centre not only main- China tains our presence in the Midwest, but also allows us to www.szhcjm.com have a convenient location for customers and vendors to [email protected] meet with our experienced team,” stated Ben Gasbarre, CO REDUCTION president of Industrial Furnace Systems. “The furnace 2 NO SURPRISES GLOBAL SUPPORT European Office equipment being installed will give us the flexibility to [email protected] process material in both atmosphere and vacuum environments. The technical centre is a key addition for us to Contact us today to find out how. Taiwan continue to position ourselves as a leader in the thermal Europe: +31 88 9494 308 | [email protected] [email protected] processing market and provide solutions to our growing Asia: +65 6909 3064 | [email protected] customer base.” www.hygear.com www.gasbarre.com

Global Tungsten & Powders Aerospace Hiwing develops high- it invested in Farsoon’s PBF-LB machines at its facility for the temperature titanium alloy powder for engineering, process development China’s aerospace industry and rapid prototyping of TA32 alloy components. AHTi took advantage Aerospace Hiwing (Harbin) Titanium alloys — other challenges in aero- of the robust and open architecture Industrial Co., Ltd (AHTi), Harbin, space component development, of the Farsoon FS271M machine, Heilongjiang, China, a specialist in including complex structures and including the ‘parameter-editor’ Security of supply titanium material R&D and manufac- faster development iterations, also included in the company’s software, turing, as well as the design, manu- challenge the established manufac- to accelerate its material processing Independent from China facturing and service of high-end turing process. development cycles with the develop- titanium alloy products, has devel- TA32 titanium alloy, with the ment of customised TA32 processing oped a high-temperature titanium composition Ti-5.5Al-3.5Sn-3Zr- parameters. High quality and purity alloy for use in Laser Beam Powder 1Mo-0.5Nb-0.7Ta-0.3Si, is a novel Using the parameter-editor, AHTi Bed Fusion (PBF-LB) Additive Manu- α-type high-temperature material application engineers were also able Responsible sourcing facturing. developed in China. It offers high to carry out a series of tests in which With the rapid expansion of the tolerance for operating temperatures they controlled the laser energy Tolling services civil aerospace industry in China, of up to 550°C, and short-term toler- density within the build chamber the demand for specialised, high- ance up to 600°C, as well as good in order to determine the optimal Recycling services temperature titanium alloys has comprehensive mechanical proper- processing parameters for producing become a critical challenge for key ties such as tensile, fatigue and creep TA32 parts. component development such as strength, making it an ideal alterna- Metallographic analysis of the aerospace engines and spacecraft. tive material for steel or nickel-base TA32 parts produced in the Farsoon In order to achieve optimised thrust– superalloy components. The alloy’s FS271M are said to show a fine weight ratio, specialised titanium production uses an advanced cold crystal grain structure, without alloys are increasingly used in parts crucible vacuum induction melting defects such as cracks or holes. The including engine compressor discs, and air atomisation technology (VIGA- mechanical properties of the parts Think Tungsten. Think GTP. blades, blisks, rotors, housing and CC) to produce high-performance were further tested and shown to intake pipes. powders with high efficiency and a offer excellent tensile strength, flex- The need for weight reduction and high yield of fine particles. ibility and plasticity under high opera- high performance in these applica- The company has been a customer tion temperatures of 500°C, 550°C tions place higher demands on the of Farsoon Technologies, Changsha, and 600°C. Whatever you create out of tungsten, be sure to start with operating temperatures of titanium Hunan, China, since 2018, when www.farsoon.com the best powders on the market. Whether for additive manufacturing, hard metals industry, oil/gas, thermal spray, tungsten metal or tungsten heavy alloy applications, Global Tungsten & Powders offers Gasbarre introduces new generation the perfect powder blends. Our laboratories are equipped hydraulic powder press with the latest analytical technologies allowing material measurements down to the atomic level. A new generation of hydraulic press, developing a system that will powder compacting press has been meet and exceed its customers’ Additionally, GTP recycles any tungsten containing scrap developed by Gasbarre, headquar- needs today and well into the you may have on hand. Benefit from our long standing tered in DuBois, Pennsylvania, USA. future. The new press design is said to The new press architecture expertise, especially in utilizing the zinc process for the include a number of updates and includes changes to surround recycling of tungsten carbide in industrial scale. improvements over the company’s guarding to improve press opera- existing machines. tion and maintenance, updates Talk to our experts to see how we can help. The company has been building to the hydraulic system, shorter mechanical, electrical and hydraulic cycle times and higher throughput presses for nearly fifty years. It also providing an improved ROI for As the COVID-19 pandemic continues, GTP’s production builds a wide range of furnaces and customers. manufactures tooling specifically for The company stated, “We believe sites remain operative 24/7. Rely on our plants in the US, the Powder Metallurgy sector. with these enhancements we have A new generation of hydraulic Finland, and in the Czech Republic to provide you with The Gasbarre team is reported to created a best in class press that powder compacting press has been an uninterrupted supply chain independent from China. have spent countless hours working will improve your bottom line!” developed by Gasbarre (Courtesy through all aspects of its hydraulic www.gasbarre.com Gasbarre) www.globaltungsten.com

FJ Industries expands tooling VBN Components selects HTL as Group department as part of growth distributor for Vibenite in Japan

FROM POWDER strategy ELABORATION TO THE VBN Components, Uppsala, Sweden, industries. Additionally, HTL has has announced a strategic partner- long-term business relations with HEAT TREATMENT FJ Industries, a Powder Metallurgy parts manufacturer headquartered in Ferritslev, Denmark, reports that it has ship with HTL Co Japan Ltd, based in universities, governmental agencies OF PM PARTS further invested in its in-house tool department as part of Tokyo, Japan, which will be a distrib- and institutes. its business growth strategy. The company’s tool depart- utor for VBN’s Vibenite materials as “We are proud and honoured to ment manufactures all the tools that customers require the company aims to establish its have agreed with HTL, a Japanese A Global Offer, One Supplier for the production of press and sinter PM parts, thereby presence in the Japanese market. enterprise in the field of high tech- allowing FJ Industries to be self-sufficient in this area. VBN Components develops metal nology business, to represent us in According to Frank Hemmingsen, Area Sales Manager alloys with extreme wear and heat the area of Additive Manufacturing,” of FJ Industries, “We want to be in control of the tool- resistance, including alloys such as stated Johan Bäckström, CEO of VBN HTL Co. Japan Ltd., is the distributor Vaccum making process. Having our own tool-making department Vibenite® 290, said to be the world’s Components. “We are convinced that of VBN’s Vibenite materials in Japan hardest, commercially available steel, this strategic agreement will be most (Courtesy VBN Components) Induction means that we are flexible and always able to give top priority to our customer’s projects. Furthermore, it allows and Vibenite® 480, reportedly the important in the business develop- Melting us to comply with customers’ desire to stick to a schedule world’s only additively manufactured ment on the Japanese market.” Acharya continued, “We are furnaces for and also to minimise risks.” cemented carbide. A K Acharya, president at HTL, convinced that by combining our the elaboration FJ Industries has also invested in improving the According to VBN Components, commented, “It is an honour and unique skills in materials and Addi- capacity and precision of its facilities. “We experience HTL has been identified as a preferred pleasure for us to represent VBN tive Manufacturing with the under- of new alloys increased demand from our customers, so we decided to partner due to its vast experience Components, with its world-leading standing of the Japanese industry, upgrade our tool shop with state-of-the-art technology,” in business development, sales and wear-resistant materials for Additive we will create a winning team for the Hemmingsen added. “We have acquired a new wire EDM marketing on high-tech markets Manufacturing and their skills in benefit of all stakeholders.” and a new sinker EDM. These investments increase our such as the semiconductor, Addi- materials, AM design and produc- www.htlco.co.jp capacity significantly. It also helps us to meet even the tive Manufacturing and aerospace tion.” www.vbncomponents.se most sophisticated requests from customers and to do so on time and on budget.” In addition to its facility in Denmark, FJ Industries has Vacuum operations in Sweden and China. furnaces for www.fji.dk debinding & sintering of PM parts Cremer expands headquarters, plans to increase engineering team

Cremer Thermoprozessenlagen has announced the addition of 250 m2 in office space at its headquarters in Düren-Konzendorf, Germany, giving the company capacity Stress to add a further ten design engineers. relieving The company is a global manufacturer of sintering & post furnaces for a wide range of Powder Metallurgy applications, including Metal Injection Moulding (MIM), Hot additive Isostatic Pressing (HIP), heat treatment and conventional manufacturing press and sinter. heat treatments Established in 1968, Cremer celebrated its 50th anni- ELEMENTAL ANALYSIS versary in 2018. One of the companies most successful furnaces has been the MIM-Master, a continuous OF METAL POWDERS & PARTS sintering furnace for Metal Injection Moulding based on the walking-beam technique. This furnace has played a ELTRA’s new and innovative ELEMENTRAC series is a mile stone for C/S and O/N/H analysis in Powder Metallurgy and Part of ECM’s Group new key role in the continued use of MIM technology for over Additive Manufacturing: easy to use, fast analysis times and reliable results for metal powders and processed samples. offer dedicated two decades and an updated version was recently intro- to laboratories duced in the new MIM-Master Neo, offering an increased production capacity with a smaller ecological footprint. www.eltra.com www.ecmlabsolutions.com www.cremer-polyfour.de/en

Design: • Initial part review Liberty Powder Metals begins powder is secured and confined to avoid • Part Feasibility Evaluation contamination from outside sources. • Design for Manufacturing production at new atomisation facility Powders then undergo further • Support/Setter design processing, including optimisation Liberty Powder Metals, part of GFG caused by the coronavirus (COVID- and characterisation, before final Process: Alliance’s Liberty Steel Group, has 19) pandemic in 2020, which has testing and dispatch to customers. • Mold/Tool Design - MIM started commercial production at restricted the number of contractors The same post-atomisation • Molding parameters - MIM its new high-tech metal powder able to work on-site and impacted processing activities are deployed for • Feedstock formulation and analysis facility in Teesside, UK. on the delivery of equipment. all metal powders in the company’s - MIM/AM • Printing parameter analysis - AM With the new facility, Liberty Commissioning of the atomiser portfolio, which includes aluminium, • Depowder process review - AM Powder Metals will produce a includes a series of ‘acceptance titanium and cobalt alloys. • Powder management - MIM/AM range of stainless steel and nickel melts’, which Liberty Powder Metals Simon Pike, General Manager of • Curing Process review - AM superalloy powders aimed at the must perform before the plant is Liberty Powder Metals, stated, “This • Part Handling and Care market for precision components handed over for full operation. The has been a great achievement amid within the automotive, aerospace, atomiser enables the company to unprecedented challenges from Debind: and engineering sectors. melt a range of defined chemis- the COVID pandemic. The resolve • TGA process and report reveiew The UK’s Atomising Systems Ltd tries and pour the liquid stream and resilience of our team and our • Debind process analysis and Consarc Engineering worked through an aperture, using inert gas contractors to overcome supply chain • Primary Binder Removal SERVICE CONTRACT closely with Liberty Powder Metals to break it into fine droplets which constraints has been invaluable.” • Secondary Binder Removal Our Team of Metal Part making experts wants to support, educate and partner with the • Binder removal analysis on equipment design for the facility. then solidify into a powder which www.libertysteelgroup.com MIM, Metal AM and other metal part making industries to share our knowledge and help In the powder production process, Sinter: spherical powder particles are you overcome challenges, develop better processes and become successful. • Sinter process review formed in a vacuum induction argon • Temperature analysis gas atomiser, incorporating an anti- • DSC process and analysis satellite facility said to increase productivity. Quality: The facility launch is the REMOTE PROCESS • Equipment needs analysis • Molding Defects analysis - MIM culmination of a two-year collabo- METALLURGIST • Print Defects Analysis - AM ration with the Tees Valley Mayor • Feedstock Quality Analysis - MIM/AM Ben Houchen and the Combined • Metallurgy review Authority, which provided £4.6 Our team will be extension - Chemistry million of funding, and the Mate- of your team and someone - Density rials Processing Institute, which 10 Hours you can call on with any - Mechanical properties housed the atomiser within its own research facilities. Installation and processing questions or Total Process Management: commissioning have successfully challenges. • Step by Step Analysis • Economics review overcome significant challenges Inside Liberty Powder Metals’ new facility (Courtesy Liberty Powder Metals) • Production Process Work Flow review SERVICE & RESEARCH & • Equipment selection and analysis 20 Hours • Facility Layout review and analysis is that our customers can showcase • Lean Manufacturing Applications Rio Tinto launches sustainability label ADVICE DEVELOPMENT the sustainability of the aluminium • Material Storage they purchase from Rio Tinto to their • Individual Process Audits for aluminium consumers, delivering full value from We draw on 20+ years of Projects are our passion. Our • Process Innovation • Packaging and Delivery International metal and mining performance, diversity in leadership, our responsible production,” stated Alf processing experience to team can partner with yours • Customer/Supplier Relationship corporation Rio Tinto, headquartered business integrity, regulatory compli- Barrios, CEO. 40 Hours help share wisdom, knowl- and bring lots of real world • Development in London, UK, has launched a new ance and transparency. Through the programme, Rio Tinto edge, do’s and don’ts of experimentation background, • Post Process Step Review concept for transparency and tracea- START will help companies meet also aims to provide technical exper- - Rework bility in the aluminium industry with its consumer demand for transparency tise through a sustainability advisory making metal parts. ultimately shortening time to - Heat Treatment new programme, START. The company on where and how the products they service and support for customers market. - Machining/Coining PHONE, EMAIL, VIRTUAL refers to this venture as a ‘nutritional purchase are made, allowing end- looking to build their sustainability SUPPORT SERVICES label’ for responsible aluminium, with users to make more informed deci- offerings and benchmark and improve SERVICE CHARGES ARE customers receiving a digital sustain- sions about the products they buy. performance, while supporting sourcing goals and access to green PAID UPFRONT ability label, via a secure blockchain, “START is a significant step GET IN TOUCH: displaying information about the site forward for the aluminium industry as financing. The START sustainability TIME IS LOGGED IN 15 MIN where the aluminium was produced, the first offering of this kind, setting label is now globally available for INCREMENTS +1.973.239.7792 covering ten criteria: carbon footprint, a new standard on transparency, aluminium purchased from Rio Tinto’s 107 Commerce Road, water use, recycled content, energy traceability and responsible produc- managed operations. Cedar Grove, NJ 07009 USA sources, community investment, safety tion from mine to market. Our vision www.riotinto.com $160.00/HOUR www.dshtech.com 18 Powder Metallurgy Review Spring 2021 © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd Spring 2021 Powder Metallurgy Review 19

Bodycote continues USA expansion with (LPC) and Corr-I-Dur (a proprietary GKN Sinter Metals announces thermochemical treatment) solu- PM Tooling new facilities in Syracuse and Elgin tions. closure of St. Thomas plant Bodycote explains that the Bodycote plc, headquartered in fully operational and replaces the new facility is part of an ongoing GKN Sinter Metals, Auburn Hills, Michigan, USA, will System Macclesfield, Cheshire, UK, has company’s ageing facility in Melrose strategy to provide the best close its auto parts plant in St. Thomas, Ontario, Canada, opened two new heat treatment Park, Illinois. possible capabilities and geograph- in around eighteen months as it consolidates production The EROWA PM facilities in the USA, one in Elgin, Along with providing all of the ical network, allowing the company at other plants. Illinois, and another in Syracuse, New processes previously offered at the to better serve customers from According to CTV News’s London Reporter, a regional Tooling System is York. Melrose Park location, the Elgin the agricultural, mining, construc- news outlet based near St. Thomas, the plant closure the standard inter- The new Elgin facility, one of over facility also offers nitriding, nitrocar- tion, automotive and various other affects 150–160 employees. Referencing his discussions seventy in North America, is now burising, low-pressure carburising manufacturing supply chains in the with the company, St. Thomas Mayor Joe Preston stated face of the press Upper Midwest region. that the closure was due to a decline in demand for the tools between the Stephen Harris, Bodycote Group company’s products. Chief Executive, commented, Powder Metallurgy parts produced by the St. Thomas toolshop and the “We’re very pleased to announce plant include smaller products, oil pump components, powder press www.ultra-infiltrant.com the opening of the new facility in suspension parts, gears, sprockets and agricultural parts. Elgin, Illinois. The purpose-built Speaking to The London Free Press, Sean Dyke, machine. facility demonstrates Bodycote’s Director of Economic Development for St. Thomas, stated Its unrivalled re- commitment to serving the that he was confident employees affected by the closure Midwest and helps us to shape the would find other jobs, as many industries are hiring in setting time also future of both our company and the the automotive sector. “Our focus has to shift now to do enables you to industry.” whatever we can to help the employees. We will work with There will be an an official our community partners,” he stated. produce small opening event when coronavirus GKN Sinter Metals recently donated $25,000 to United series profitably. (COVID-19) related restrictions are Way Elgin Middlesex, a non-government funder of social A SOLID LINE OF THINKING: lifted, added the company. services based in St. Thomas and London, Ontario. Bodycote also announced that www.gknpm.com www.erowa.com SINTERING WITH A SOLID its 5,600 m2 (60,000 ft2) Syracuse facility is now operational, offering INFILTRANT a wide range of heat treatment processes. These include vacuum heat treating, atmospheric carbur- Euro PM2021 Congress & ising, low-pressure carburising, Exhibition to take place carbonitriding, ferritic nitro carburising, nitriding and aluminium online only heat treating. The company aims The European Powder Metallurgy Association (EPMA) has for the site to secure all major announced that the Euro PM2021 Congress & Exhibition, more info OEM approvals as well as Nadcap initially scheduled to take place in Lisbon, Portugal, from accreditation, which it is said October 17–20, will now take place online from October to be already well on the way to 18–22. The decision was made due to the ongoing uncer- achieving. tainty caused by the coronavirus (COVID-19) pandemic. The facility investment is part The online event will take place over five days, allowing of Bodycote’s strategy for further more time for delegates to network, and catch up with expansion in the USA. An official parallel sessions they may have missed. The technical opening event for this site is also programme was confirmed in February and represents expected to take place when condi- an expanded array of papers from all strands of PM. tions allow. The EPMA explains that it will build upon the success “We are very pleased to of the Euro PM2020 Virtual Congress with improved announce the opening of another networking features, break-out ‘rooms’ for discussion, new facility in the USA, this time in and increased presence for sponsors and media part- Syracuse, New York. This invest- ners. ment demonstrates Bodycote’s Additionally, Euro PM2021 will feature a virtual exhibi- continuing commitment to align tion for the first time, allowing delegates to explore a resources to serve our customers digital showroom of PM companies, promoting their YOUR WROUGHT/WIRE INFILTRATION SOLUTION. across North America,” added latest developments to the entire PM supply chain. Harris. 1868 Corniche Drive, Zionsville, IN 46077 Further information is available via the event website. www.bodycote.com www.europm2021.com 888-ULTRA-55 . [email protected]

Industry News | contents | news | advertisers | events | website | e-newsletter | | contents | news | advertisers | events | website | e-newsletter | U.S. Metal Powders, Inc. Global Powder ECTA president comments on the Metallurgy European cutting tool market AMPAL | POUDRES HERMILLON Database receives During the VDMA Precision Tools’ exemption from customs duties, the update annual press conference, Markus trade agreement is said to impose Horn, European Cutting Tools Asso- new bureaucratic burdens. For The European Powder Metallurgy ciation (ECTA) president, delivered example, since January 1, British Association (EPMA) has announced an analysis of the current Euro- products can only be exported with an update to the Global Powder pean aspects of the cutting tool significant customs documents. Metallurgy Property Database and clamping devices industry. His Italy was the first to be hit (GPMD). The free-to-use database presentation, titled ‘Focus on Europe significantly by the pandemic, contains data representing many – How is the economic situation in continued Horn, and reported sharp thousands of tests on hundreds of important neighbouring countries?’, declines in orders of around a different material grades, collected explores the impact of the corona- quarter in the first nine months of from a wide range of sources. Now, virus (COVID-19) pandemic on the 2020 due to the imposed company with a new interface and cloud- market and presents his outlook for closures. But, at the end of the based server, the response time for 2021. year, production in the automotive detailed searches has been greatly For cutting tool manufacturers industry in Italy picked up again improved. throughout Europe, the range of strongly, giving cause for hope. The GPMD was launched in customers and the overall economic France also recorded negative 2004 as a joint project between situation are not fundamentally developments with the effects of the pandemic and reported declines the EPMA, Metal Powder Indus- different from those of German C tries Federation (MPIF) and Japan suppliers, explained Horn; analysis of of 35% in the French market for M Powder Metallurgy Association the EU-27 countries from January to cutting tools and as much as 50% or (JPMA), with the Asian PM Associa- October 2020 shows a negative devel- clamping devices. Y

tion (APMA) joining the database opment similar to what Germany In Spain, the downturn was also CM experienced. The COVID-19 pandemic said to be severe. The Spanish partners in 2020. MY Originally covering the ferrous hit everyone in 2020, and overall, the market is heavily dependent on CY PM industry, the GPMD has been EU-27 countries saw their deliveries the automotive industry, whose updated a number of times over the drop by 20%, he stated. production was also restricted. CMY Here, the recovery has now begun, years to include the non-ferrous Regarding the European domestic K PM and MIM sectors. Information market, 60% of cutting tool exports albeit still somewhat subdued. But has since been added covering from the 27 EU member states do not the production forecasts for 2021 Advanced Engineered Aluminum Powders strain-controlled fatigue data, leave Europe, Horn reported. Another are positive and the government’s along with the ability for users to 13% of total deliveries go to other planned investment programmes reference microstructural phases European countries. This means that are likely to boost this further. Shaping the Future Together in materials processed by conven- the European domestic market is Switzerland reported a gradual tional sintering, elevated tempera- the sales market for almost three- recovery after its sharp lockdown ture sintering, accelerated post- quarters of European tools. in April. The watch industry, a United States Metal Powders, Inc. has been a global leader in the production sintering cooling, and more. In contrast, tool exports from the vital focus for the country, and the The GPMD is fully searchable EU to the UK are reported to have automotive sector picked up again. and distribution of metal powders since 1918. Together with our partners and and outputs can be exported to fallen more sharply after Brexit. The The pandemic worsened again in subsidiary companies, AMPAL and POUDRES HERMILLON, we are helping to shape several well-known FEA packages. decline was 28%, while the deliveries October, but, for now, the number of The data is displayed in a user- from the UK fell by 29%. Despite the infection cases is declining. the future of the powder metallurgy industry (PM). friendly format, viewable in both The largest non-European tabular and graphic formats and market is the USA. Traditionally, it is hoped it will be of particular about one in ten European cutting Dedicated Research, Leading Edge Technology, Global Production & Customization interest to design engineers in a tool products goes to the American range of industries. market. Here, deliveries fell by • Aluminum based premix powders • Specialist distributor of carbonyl iron 25%, reported Horn. By contrast, In 2021, there are plans to • Nodular and spherical aluminum powders and stainless steel powders further expand the GPMD to include EU-deliveries to the Chinese market specific metal Additive Manu- only fell by 5% up to October. China, • Aluminum alloy powders facturing data. Anyone wishing as the second most important sales to assist with this in any way can market outside the EU, was a stabi- contact Kenan Boz at the EPMA. ECTA President Markus Horn lising factor for European exports. www.pmdatabase.com (Courtesy ECTA) www.ecta-tools.org Tel: +1-908-782-5454 (x215) Email: [email protected] © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd USMP 22 Powder Metallurgy Review Spring 2021 Spring 2021 Powder Metallurgy Review 23 www.usmetalpowders.com AMPAL|POUDRES HERMILLON | contents | news | advertisers | events | website | e-newsletter | | contents | news | advertisers | events | website | e-newsletter | Industry News

wake of COVID-19, we delivered strong Sandvik reports Q4 2020 results, sees and improved adjusted margin of maintained recovery from COVID-19 20.1% (19.1) in the quarter, supported by our short- and long-term savings Sandvik AB, headquartered in and oil & gas remained subdued, initiatives, which is a confirmation of Stockholm, Sweden, has reported its customer activity in engineering and, our tight cost control and our agility results for the fourth quarter of 2020, in particular, automotive intensified in during this year’s challenging market in which the business maintained the period. conditions.” its recovery from the impact of the Demand in parts of Europe “During the quarter, we delivered coronavirus (COVID-19) pandemic. improved sequentially driven by approximately SEK 920 million in Revenues declined organically by automotive and mining activity, and savings and lower discretionary spend -6%, while adjusted operating profit overall organic order intake declined for the group compared with the declined by -11% to SEK 4,505 million year on year by -2%. North America preceding year. However, the headwind (Q4 2019: SEK 5,066 million). Order declined with -23% while order intake from currency had an impact on both intake declined organically by -2% in Asia increased by 4%, reflecting the reported revenues and reported oper- and the adjusted operating margin continued economic recovery in the ating profit. Organic order intake and increased to 20.1% (Q4 2019: 19.1%). region. revenues for full-year 2020 declined During a second wave of Stefan Widing, president and by -12% and -11% respectively, heavily COVID- 19, the company states that a CEO of Sandvik, commented, “The impacted by the COVID-19 pandemic. gradual recovery was seen in specific pace of recovery that was noted at At the same time, Sandvik has been end-markets and segments in the the beginning of October continued able to maintain resilient adjusted fourth quarter. Organic order intake throughout the fourth quarter. margins of 16.9%.” for the group was slightly nega- Demand in our long-cycle mining During the quarter, the acquisi- tive, but, excluding major orders, business was strong and we saw a tions of US-based CGTech and the showed a positive development sequential uptick in our short-cycle Indian company Miranda Tools were year on year for the first time since business. Consequently, organic completed. Sandvik also acquired a the first quarter of 2019, fueled by order intake (excluding major orders) minority stake in the privately-owned strong demand in the mining busi- for the Group grew by 3% year on US software company Oqton. ness. While demand in aerospace year. Despite lower revenues in the www.home.sandvik/en/

Hilderbrand & Cie SA announces The powder makes the rebrand and relocation

Swiss company Hilderbrand & Cie Since 2013, Hilderbrand has difference SA has rebranded as C Hafner & been part of C Hafner GmbH, Hilderbrand SA. Along with this Wimsheim, Germany, a company change comes a planned reloca- which supplies precious metal Meeting the highest standards for drying and powder quality tion of its facilities to the communal technology products and services. Espace Tourbillon, a five-building Along with its own experience, this complex located in Plan-les-Ouates’ position in the group allows the GEA spray drying plants unite innovation and experience to state-of-the art industrial park in Geneva, Switzer- company to offer a full range of process technology for the production of hard metals and advanced ceramics. land. Hilderbrand expects its move precious metals products. Thierry We have pioneered this technology, and our expertise helps you to meet the to be complete by the first quarter Copponnex, CEO, believes the new C Hafner & Hilderbrand develops and of 2021. location will increase Hilderbrand’s produces a range of fine spherical highest standards of powder quality, powder size distribution, residual moisture The company develops and visibility, allowing access to the precious metal powders suitable content, bulk density and particle morphology. All GEA plants are designed to produces a range of fine spherical wider Swiss market. for a range of applications including comply with the strictest requirements regarding eﬃ ciency, health and safety precious metal powders, which Having moved a short distance AM and MIM (Courtesy C Hafner & and environmental compliance. Customer-oriented service concepts guarantee are especially suitable for use in within the canton of Geneva, the Hilderbrand SA) a seamless support for instant productivity and performance. Additive Manufacturing and other company is now at the heart of the manufacturing technologies such watchmaking industry, which is For contact details: gea.com/contact as Metal Injection Moulding (MIM) hoped will allow for more syner- ration will allow the company to and powder spraying. Typical areas gistic relationships between Hilder- further develop. The final building in of application are jewellery and brand and some of its consumers. Espace Tourbillon is scheduled for watches, technical or medical Copponnex has stated that he hopes completion by the end of this year. applications. this location-facilitated collabo- www.hilderbrand.ch

GTP and Almonty Industries drive Registration reactivation of Sangdong tungsten mine opens for PowderMet2021 Plansee Group, Reutte, Austria, is money,“ stated Hermann Walser, working with Almonty Industries, a CEO and president of GTP. hybrid conference global mining company headquar- “Successful commissioning requires tered in Toronto, Ontario, Canada, to financially strong investors, long Registration is now open for the drive the reactivation of the Sang- approval processes, complex international conference on Powder dong tungsten mine in South Korea. production equipment, and extensive Metallurgy & Particulate Materials Acquired by Almonty in 2015, the production expertise.“ (PowderMet2021) which will take Sangdong mine is being prepared for Located in South Korea’s place both online and in-person at use with an eye towards safeguarding northeast, the Sangdong mine was the Walt Disney World Swan and long-term primary supply of tungsten discovered in 1916 and served as Dolphin in Orlando, Florida, USA, powder for the Plansee Group tung- one of the world’s leading tungsten from June 20–23, 2021. Organised sten manufacturer, Global Tungsten producers for forty years. Despite and sponsored by the Metal Powder Powders (GTP), Towanda, Pennsyl- rich tungsten ore deposits, the mine Industries Federation (MPIF), the vania, USA. ceased production in 1994 due to the hybrid event will feature traditional GTP is said to have enjoyed a close low price of tungsten. live presentations which will be working relationship with Almonty for Currently, Almonty’s tungsten ore recorded and available on-demand a number of years, having entered concentrates are mined in Spain and to all participants for a limited into long-term delivery agreements. Portugal, with Sangdong planned to time. Almonty supplies tungsten ore start operations in 2022. PowderMet is relevant to concentrates, which GTP processes www.globaltungsten.com professionals from every part of into a variety of tungsten powders. www.almonty.com the industry, including buyers and “The development of a mining www.plansee.com specifiers of metal powders, tooling project takes a lot of time and and compacting presses, sintering furnaces, furnace belts, powder handling & blending equipment, ZF announces $200 million investment in QC and automation equipment, particle-size & powder-character- US vehicle manufacture isation equipment, consulting & research services and more. ZF, a German based company employs 2,200 people and has the The MPIF states that it will be with its American headquarters in capacity to produce 1.2 million working to adhere to all Centers Livonia, Michigan, is to invest $200 transmissions per year. for Disease Control & Prevention million in commercial vehicle manu- The ZF PowerLine transmis- (CDC), World Health Organization facturing in North America. Begin- sion is designed for medium-duty (WHO) and local authorities’ recom- ning in 2023, ZF plans to produce commercial trucks, buses and mendations to ensure safety for its PowerLine 8-speed automatic heavy-duty pickup trucks. The all in-person participants. Further transmission at the company’s transmission is based on ZF’s information on these measures is manufacturing facility in Gray Court, 8-speed automatic transmission available through the MPIF website. South Carolina – a move which will design, which provides maximum The four-day event will be held result in over 500 local jobs. spread with the fewest moving parts, alongside the Additive Manufac- At the end of 2020, ZF began reducing friction and the need for turing with Powder Metallurgy production of the PowerLine 8-speed fluid. (AMPM2021) and International automatic transmission at its global Dr Martin Fischer, president of Conference on Tungsten, Refrac- headquarters in Friedrichshafen, ZF North America and a member of tory & Hardmaterials (Tung- Germany, beginning to serve North the board of management stated, sten2021) conferences. Between American consumers in 2021. The “ZF is a 106-year-old technology the three co-located conferences, US base of PowerLine is the ZF leader that has been in the US for over 200 technical presentations Transmissions Gray Court in South many decades, and this investment will be made. Carolina – home to BMW, Michelin in US manufacturing of sustainable Registrants enrolled prior to and other suppliers. Since opening driveline technology further proves May 7, 2021, can benefit from a in 2012, the facility has produced our commitment to the North Amer- discounted rate. 5.5 million automatic transmissions. ican commercial vehicle market.” www.powdermet2021.org Currently, the 157,000 m2 facility www.zf.com www.mpif.org

losing sight of other areas such as Gränges targets AM with new Gränges heat exchangers and automation, BorgWarner to supply transfer cases for Powder Metallurgy division where the company still sees great Nissan SUV’s and Pick-up’s potential. Gränges, a leading global supplier of “We are a slim and flexible Greta D’Angelo, Additive Manufac- BorgWarner Inc., headquartered in Transmission Systems. “With our rolled aluminium products for heat organisation with focus on partner turing Business Development Lead, Auburn Hills, Michigan, USA, has experience in the development of all- exchanger applications and other and stakeholder management,” told Powder Metallurgy Review: secured a contract to supply its part- wheel drive solutions, we are able to niche markets, headquartered in commented Filip Fernqvist, Managing “Gränges has a combined experi- time transfer cases to the Japanese provide a part-time transfer case that Stockholm, Sweden, has established Director at Gränges Powder Metal- ence and in-depth knowledge in car manufacturer Nissan, for produc- enables improved vehicle dynamics BorgWarner to supply its durable Gränges Powder Metallurgy. lurgy, told Powder Metallurgy Review. several key areas – for example, tion of its Navara pick-up and Paladin and performance. This is our first part-time transfer cases to Nissan With a responsive organisation and “We are both a powder producer Powder Metallurgy, aluminium SUV models. The deal marks the collaboration with Nissan in this area for production of Navara pick-up two powder production sites, Gränges and alloy developer, able to produce market and alloy development for first time BorgWarner has supplied and we look forward to supporting and Paladin SUV models (Courtesy sees great opportunities in the powder in house, both in France as heat exchanger applications. This transfer cases to Nissan, extending their business goals by delivering BorgWarner) Additive Manufacturing sector and well as in Germany.” heritage plays an important role and their existing relationship. exceptional technology, quality and believes that this newest division will Gränges has stated that its objec- puts us in a position of competitive The company’s two-speed, value.” serve as an important platform for tive is to become a leader in the advantage. AM powder is our core shift-on-the-fly transfer cases are Part-time transfer cases offer The transfer case solution from growth within the fast-paced markets manufacture of niche and custom business, but we are looking into said to feature driver-selectable various operating ranges, including BorgWarner reportedly allows the of powder materials and Additive AM-grade aluminium powders for a engineering services and down- controls with an electric motor for two-wheel drive (2WD) high, four- driver to shift between two-wheel and Manufacturing. The main production range of applications. The company is streaming opportunities as well for quick, smooth and accurate shifting wheel drive (4WD) high and 4WD all-wheel drive modes. The system facility is located in St Avold, France, targeting the aerospace and auto- prototype production.” between different drive modes. low. A 2WD high range is normally provides superior noise, vibration and with sales and technical development motive industries, which are under- Delivering premium powders of “We are proud to have the oppor- used on paved, dry roads; 4WD high harshness (NVH) performance for based in Velbert, Germany. going the fastest growth, without high quality with fast development tunity to provide BorgWarner’s proven for extra traction on snow-covered superior drivability regardless of the times is one of Gränges’ core values. transfer case technology to Nissan roads or when driving off-road on terrain, along with speedy drive mode The company believes a key to its for production on various platforms,” flat terrain; and 4WD low for driving shifting of 0.7 seconds or less and success is a close collaboration stated Dr Volker Weng, president off-road on rough terrain or when range shifting of one second or less. with customers and partners, which and General Manager, BorgWarner navigating steep grades. www.borgwarner.com ensures a strategic positioning within the AM ecosystem. “It is very important for us to be on the market with a competitive product that is relevant to our customers,” Fernqvist added. “That’s why we are always on the lookout for partnerships and beta testers for our Gränges Powder Metallurgy’s goal is to become a leading manufacturer of new materials.” niche and custom AM-grade aluminium powders (Courtesy Gränges) www.granges.com

During these pilot trials, up to Swedish Energy Agency grants financial one fifth of the fossil carbon will be support to Höganäs’ goal of climate replaced by biocoke. If this were to be implemented, it would equate neutrality to a reduction in carbon dioxide emissions of 29,000 tonnes per Sweden’s Höganäs Group has Thanks to the Swedish Energy year, approximately 13% of the been granted financial support by Agency’s €270,000 contribution, company’s Swedish emissions. the Swedish Energy Agency to aid the group states that it is now able “Replacing fossil coal with PARTICLE CHARACTERIZATION the group in reaching its goal of to conduct pilot tests with climate- renewable energy is more compli- becoming climate neutral by 2045. neutral biocoke in one of its manu- cated than it sounds,” commented OF METAL POWDERS An important step in reaching facturing processes. The project will Ryan Robinson, project leader. that goal involves replacing fossil start immediately and is scheduled to “Our process has been developed Microtrac MRB offers the widest range of particle analyzers for comprehensive characterization of metal powders. coal with renewable biocoke, in what run until the end of 2022. over more than 100 years and I CAMSIZER X2 – dynamic image analysis for I CAMSIZER M1 – static image analysis based I SYNC analyzer – combination of laser is called the ‘Höganäs process’, “The project is a central part of our even small changes can have a reliable determination of size distribution, on a powerful microscopic evaluation for diffraction and image analysis with a wide which enables carbon dioxide work to reduce our carbon dioxide significant impact on process and oversize, fused and defective particles. most accurate shape measurement. measuring range and maximum flexibility. emissions to be reduced and, in the emissions and become climate product quality. This project will long term, help the Höganäs Group neutral by 2045,” stated Magnus give us important insights.” www.microtrac.com become fossil-free. Pettersson, Energy Coordinator. www.hoganas.com

Korean Institute of Rare Metals produces rare earth permanent magnets from ASM’s NdFeB

The Korean Institute of Rare Metals available alloy. KIRAM has stated (KIRAM) has successfully produced the results indicated that ASM’s and tested 2 kg of pre-sintered pre-sintered magnet exhibited permanent magnets, produced superior magnetic properties than with high-purity NdFeb powder the commercial sample, indicating from a Korean pilot plant owned ASM’s NdFeb alloy is suitable for the NdFeB strip alloy SEM/EDS results by Australian Strategic Materials production of rare earth permanent (Courtesy ASM) (ASM)’s, headquartered in Burswood, magnets. ASM hopes this will prove Australia. a further step in its goal of becoming The KIRAM scientists made a an independent, fully-integrated part of an initial 5,200 tonnes per strip-cast sample using 5 kg of ‘mine to manufacturer’ producer of year plant in Korea, projected to be ASM’s NdFeB powder. The strip was critical metals. fully operational by mid-2022.” subsequently examined with scan- “We now have confirmation of Woodall concluded, “The excel- ning electron microscopy (SEM) and the quality and high purity of the lent support and collaborative work energy dispersive X-ray spectroscopy permanent magnet alloy and titanium between the Ziron Tech and KIRAM (EDS) in order to confirm the micro- powders ASM can deliver to the teams delivered a truly significant structure and magnetic orientation. Korean industry and, eventually, result. It provides ASM with confi- Some of the Ziron Tech NdFeB the global markets,” stated David dence that our integrated business alloy was also pressed into a 2 kg Woodall, ASM Managing Director. model – from the Dubbo Project block in order to measure the “ASM is now planning to advance in to metals production – can play an magnetic characteristics using the next few months with the detailed important part in the Korean Govern- vibrating sample magnetometry engineering, incorporating both the ment’s ‘New Green Deal’.” (VSM) compared with a similar recently produced titanium and, now, www.asm-au.com sample made from a commercially the permanent magnet powders as www.kiram.re.kr

MPIF announces Distinguished Service GKN’s Menomonee to PM awards Falls receives award

The Metal Powder Industries Feder- • Peter A. dePoutiloff, PMTII, SSI The GKN Sinter Metals team in Meno- ation (MPIF)’s Awards Committee Sintered Technologies monee Falls, Wisconsin, USA, has has announced the recipients of the • Utpal Gangapadhyay, MPP received the Nexteer Perfect Quality 2021 MPIF Distinguished Service Award for 2020. The award is presented • Claus Joens, Elnik System to Powder Metallurgy (PM) Award. to Nexteer suppliers for achieving zero Each year, the award recognises • John L. Johnson, Novamet quality claims over all product groups individuals who have actively served Specialty Products from a specific location. the North American PM industry • Arthur E. Jones, Symmco, Inc. GKN produces components for for at least twenty-five years and, • Enrique Lavernia, Univ of Cali- hydraulic power steering pumps for in the minds of their peers, deserve fornia Irvine Nexteer, and has partnered with special recognition. • Stephen C. McCrossan, the company for over thirty years, a 2021 Award recipients (Company Plansee USA LLC partnership continued from the years name in parenthesis indicates before, when Nexteer was known as • Salvator Nigarura, Global Tung- employer at the time of retirement): Delphi Steering. sten & Powders Corp. www.sacmi.com “I am proud of the team. It shows • Rodney Brennen, Metco • Gregory D. Wallis, Dorst the leadership, commitment and Industries Inc. America, Inc. ownership in meeting and exceeding • James R. Dale (Metal Powder The awards ceremony will take customer expectations,” stated Bo Industries Federation) place during PowderMet2021, June Muzyk, VP of Quality. • Scott Davis, Hoeganaes 20–23, Orlando, Florida, USA. www.gknpm.com Corporation www.mpif.org www.nexteer.com

www.sacmi.com/metals

therefore, knows a vast amount about MTC Powder Solutions chairman sees running a HIP unit and maintaining growth through collaboration the efficiency, something that could increase efficiency further at MTC PS,” Since the acquisition of Sandvik The decision to acquire what has explained Hirayama. Powder Solutions by the Japanese since become MTC Powder Solutions In recent years, MTC PS has engineering company Metal Tech- was Hirayama’s sureness that Near successfully designed tailored PM NNS nology Co Ltd (MTC) in April 2020, Net Shape Hot Isostatic Pressing HIP parts, solving many challenges MTC Powder Solutions AB (MTC PS), (NNS HIP) would allow MTC to expand encountered in rigorous indus- Surahammer, Sweden, has reported into new markets; the acquisition tries such as oil & gas and nuclear consistent, positive changes. An of MTC Powder Solutions is said to energy. As a result, there has been an interview with the new Board of be the first step in the creation and increased demand for mass produced Directors Chairman, Tetsuhito growth of a NNS HIP business in PM NNS HIP components, which MTC Hirayama, recently published by MTC Europe. As to why Hirayama moved PS believes itself to be well positioned PS, provides an insight into the new to Sweden, he stated that it was to meet with MTC as its owner. owners and their ambitions for the crucial to provide an environment in Hirayama also stated that the company. which the employees of MTC Powder company’s focus is currently on the Hirayama is a member of the Solutions were able to feel and see utilisation of what is currently available founding family of MTC, though he an actual change. He believes MTC and installing quick investments to worked a variety of positions in the needs to have a deep understanding improve current practices. Recently, company to build experience and and synergy with MTC PS in order to MTC PS has reported an investment hands-on insights in all aspects of effectively benefit from combining the in a laser cutter, HIP upgrade and the the company’s inner workings. He two companies’ strengths. hire of more employees. began working with heat treatment Hirayama acknowledged that the With MTC’s addition of technolo- equipment before moving into sales, cultural exchange can be a difficult gies such as Additive Manufacturing, development and general affairs. process, between two countries with brazing, and the bonding of dissimilar In 2005, Hirayama became the different systems, MTC’s hopes to materials, there is the prospective Managing Director for the General offer the chance of shared knowledge, for continuing future growth of MTC Affairs Division at MTC’s Tokyo head- expecting stable coordination between Powder Solutions. To achieve this, quarters, where he was responsible the teams will lead to improved it requires a long-term perspective, for maintaining company operations quality, customer satisfaction and understanding of the customers’ and planning new initiatives, such as in-person workings and morale. needs, and close collaboration and corporate acquisitions and business “MTC owns and runs over nine- integration. alliances. teen HIP units on different sites and, www.mtcpowdersolutions.com Benefits APMI International announces recipient • Highest product quality of 2021 Fellow Award

• Cost efﬁciency through energ y APMI International has announced opment; mentoring/outreach and Cynthia Freeby, Regional Sales contributions to APMI International and gas-saving design Manager at Ametek Specialty Metal committees. • Maximum safety Products, as the recipient of its 2021 During her forty-year Powder Fellow Award. Established in 1998 Metallurgy industry career, Freeby • Full compliance with machine and said to be APMI International’s has been dedicated to the advance- most prestigious award, the Fellow ment of the PM industry. She directive Award recognises APMI members co-chaired the annual Metal Powder APMI International announces • Shorter process times with the for their significant contributions Industries Federation (MPIF) PM/87 Cynthia Freeby as the recipient of its to the goals, purpose, and mission technical conference and has served 2021 Fellow Award (Courtesy APMI use of intelligent de-waxing of the organisation, as well as on many boards and committees. International) for a high level of expertise in the Freeby is reportedly the only person technology and powerful quick technology of Powder Metallurgy, to have chaired three APMI chapters Award in 2019 for her work in devel- practice, or business of the PM (Philadelphia, Dayton, and Michigan, oping PM standards. cooling industry. USA), after holding numerous officer Freeby will receive elevation to Fellows are elected through positions within each chapter. She Fellow status at the PowderMet2021 their professional, technical, and received the MPIF Distinguished Opening General Session, June 21, scientific achievements; continuing Service to PM Award in 2005, as well 2021, in Orlando, Florida, USA. professional growth and devel- as the ASTM Distinguished Service www.apmiinternational.org Phone: +49 (641) 68 690 - 140/141 • Mail: [email protected] • www.pvateplaivs.com 32 Powder Metallurgy Review Spring 2021 © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd Spring 2021 Powder Metallurgy Review 33 Industry News | contents | news | advertisers | events | website | e-newsletter | | contents | news | advertisers | events | website | e-newsletter | Industry News

companies to import the raw mate- UK rare earth facility to offer a rials critical to the Green economy ECM Group launches ECM Lab Solutions sustainable magnet supply chain from unsustainable sources,” stated Paul Atherley, chairman of Pensana The ECM Group, headquartered in ductor and renewable energies. Pensana Rare Earths Plc, headquar- the world’s largest non China-based Rare Earths. “The Saltend facility has Grenoble, France, has launched ECM The group states that its labora- tered in London, UK, has announced producer of rare earth oxides from its the potential to become a world-class Lab Solutions, a laboratory furnace tory furnaces are the perfect tools to that Saltend Chemicals Park, located facility in Malaysia. producer of rare earth oxides and to division dedicated to offering solutions work on samples up to small-scale in the Humber Local Enterprise Part- The Saltend Chemicals Park is help establish a sustainable supply to laboratories and research centres. production. The systems are based on nership, has been selected as the home to a number of chemicals chain for the manufacture of powerful ECM Lab Solutions gathers all its industrial technology and equip- The Turquoise furnace is a hori- proposed site to build the UK’s first and renewable energy businesses, permanent magnets critical for the products from the ECM Group that ment from ECM Technologies, ECM zontal vacuum furnace from the rare earth processing facility, with including BP Petrochemicals, Ineos, offshore wind and electric vehicle are designed and adapted to research Greentech, Semco and Cyberstar. ECM Lab Solutions range that is a view to helping create the world’s Nippon Gohsei and Air Products, industries in the UK and Europe.” and development for four main fields, Further information is available via specifically designed to heat treat first fully-sustainable magnet metal strategically located on the Humber The company is looking to which include metallurgy & heat the ECM Lab Solutions website. alloys prone to oxidation (Courtesy supply chain. estuary, a gateway to Europe and the commence development of the treatment, crystal growth, semicon- www.ecmlabsolutions.com ECM Lab Solutions) Working with Wood Group, a UK’s busiest ports complex. Longonjo mine in Angola, which is UK engineering consultancy, the “The Saltend Chemicals Park being established to international processing facility would become one offers an exceptional range of services standards as one of the world’s most Matexcel offers of only two major producers outside allowing us to plug into power, water, sustainable rare earth mines. This China of rare earth oxides used in the reagent supplies and services and to will supply the UK facility with mixed metal powders manufacture of powerful permanent recruit a highly-skilled local workforce rare earth sulphates to process into magnets, critical to the offshore wind at internationally competitive rates. separated magnet metal oxides. Matexcel, Bohemia, New York, USA, and electric vehicle industries. Lynas It is very clear that it is no longer Detailed discussions with local has acted as a service provider in Corporation of Australia is currently acceptable for British and European councils and planning agents have materials science since 2007 in the confirmed that the necessary plan- supply of polymers, nanoparticles ning permission for the proposed UK and natural materials. The company facility can potentially be obtained has announced it is now expanding with sufficient time for it to be its range to provide a selection of constructed in line with the Longonjo metal powders for research require- mine development. The company ments. has commenced discussion with the Matexcel is now offering hybrid UK’s Department for International water/gas and plasma atomisation Trade and is working with the various technology to meet the needs of its initiatives supporting the electric customers working in Powder Metal- vehicle industry and the offshore wind lurgy, metal processing and Additive Saltend Chemicals Park has been selected as the site to build the UK’s first industry in the UK. Manufacturing research and devel- rare earth processing facility (Courtesy Pensana Rare Earths) www.pensana.co.uk opment. Bespoke manufacturing strategy services are also offered by the company. “Besides advanced production Because of the inherent shape- equipment and standard production Horizon explains benefits of Powder making capabilities of powder metal, technology, we also have modernised SMC materials also allow manufac- Metallurgy SMCs in electric motor NVH testing laboratory that can ensure the turers to take advantage of complex high quality and consistency of the In a recent blog post, Horizon and generate instantaneous max geometries. Stators, for example, can final products. Providing professional Technology, St. Mary’s, Pennsyl- torque, eliminating the need to rev be made more effectively with PM solution of metal powders to our vania, USA, reports on how the the engine, explains Horizon. methods, and SMC materials can boost customers is our aims,” commented use of Powder Metallurgy in the Manufacturers of automotive their magnetic performance. Johnson Brown, one of Matexcel’s production of automotive electric electrical components have been PMand SMC materials can create representatives. motors can optimise performance, using steel laminations for a long lighter components with improved The company states its most reduce NVH (noise, vibration, and time, but that method is restrictive magnetic performance that not only popular metal products so far include harshness) levels and improve user in a few ways. The author states make electric motors more efficient, but titanium alloys and nickel-base experience. that parts made with laminations also improves NVH and reduces cost. superalloys, which are atomised by Traditional internal combus- are noisier, for example, because of “At the end of the day, creating a a plasma rotating electrode process tion engine vehicles suffer from the effect the vibrations have on the more efficient electric motor at a lower (PREP). Other available metal much higher NVH than electric lamination stack. Through the use cost will improve the driver experience, powders include those based in Co, vehicles. With almost zero NVH, of Powder Metallurgy Soft Magnetic and the use of the SMC material will Cu, Fe, Ni, Pd, metal oxide, pure the most sound heard is often just Components (SMC), the production of help extend the range of the electric metal powders and more. a minimal gear whine. Electric a single component can replace the vehicle,” the author added. www.matexcel.com motors are typically more compact laminated parts and reduce NVH. www.horizontechnology.biz reklama U-FAST_A4_2021.indd 1 11.03.2021 13:12:21

Safina offers range of Equispheres launches new aluminium “Equispheres’ unique proprietary atomisation process is carefully metal powders for Additive powders controlled and can be managed with Manufacturing precision,” stated Dr Conlon, CTO at Equispheres, a materials science part strength and performance Equispheres. “Powder features such company based in Ottawa, Ontario, across a wide range of applications as PSD (particle size distribution), With beginnings in the mid-19th century, Czech company Canada, has launched a new line of and that achieves a 20–30% increase morphology, and chemistry can be Safina has a long tradition in the complex processing powder products intended to assist in the a-basis design allowable over optimised to achieve specific behav- and manufacture of products from precious and nonfer- customers in achieving optimal traditional powders. iour in the laser melting process and rous metals such as thermocouple wires, PGM wires, results for speciality metal Additive to meet defined application require- plates and tubing, sputtering targets, labware, chemicals, Sunrock Ceramics specializes in high Manufacturing applications. Equispheres Precision ments.” powders and others. The company explains that the Powder designed to support applica- Evan Butler-Jones, Director alumina industrial ceramics for the For many years, the company produced silver powders three new powders are variations tions where fine features and preci- of Applications Engineering, most severe sintering applications – prepared by reduction from silver nitrate solution in a on its original high-performance sion (as related to CAD design) are of commented, “The unique nature of in the powder metallurgy and large range of particle sizes with dendritic shape. These aluminium alloy which was engi- paramount importance. This powder the Equispheres powder requires the powders are commonly used in the fields of sintered technical ceramics markets. neered to offer enhanced features has proven to provide a 50% improve- use of special printer parameters contacts, carbon brushes and EMI/RFI shielding. for either increased build precision, ment in dimensional accuracy. to achieve the best outcomes. Our However, chemically-precipitated powders, such as these, enhanced additively manufactured research team has been working with Broad product offering for the unique are not suitable for technologies like Additive Manufac- part strength, or faster production Equispheres Production our industrial partners in automotive turing or cold spraying. demands of the PM and MIM industries speed and volume. In addition to the Powder designed to reduce the cost and aerospace to arrive at the optimal Safina initially invested in cold spray technology in • Pusher plates for rapid cycle hydrogen original atomised AlSi10Mg powder per part manufactured, with features methods for the application of our 2012 for the production of rotary targets for the flat glass Equispheres produces, the new metal designed to facilitate the rapid powder.” atmosphere pusher furnaces industry. Rotary sputtering targets produced from gas powder products include: production of items without compro- Equispheres plans to announce an atomised powder by cold spraying ensure superior prop- • Setter tiles and other sintering trays mising mechanical performance. The additional line of products, specifically erties like low porosity, gas content, high purity – 4N, fine • Thin profiles Equispheres Performance company is working on parameter for sintering and use in Binder Jetting and homogeneous grain size. In line with this develop- Powder designed to provide sets to increase production speeds by (BJT) machines, in Q1 of 2021. • Specialty contoured surfaces ment, the company invested in a gas atomiser suitable for enhanced additively manufactured three to four times. www.equispheres.com • Wide assortment of press tooling the production of silver powder for cold spray technology. The company soon became aware that its uniquely-devel- • Casting available for more complex oped processed powders have properties for cold spray shapes and AM which the standard powders did not. With this in mind, it started the external production of gas atomised Serving worldwide PM markets with fast powder for partners, which is currently a keystone of turnaround Safina’s portfolio. • Products presently in service in Europe, Asia & U.S. Powders from Safina Safina’s powder range extends to three main types: • Fast leadtimes reduce in-house stocking gas atomised; chemically precipitated; and its newly- levels developed coated powders, which are manufactured by hydrometallurgy. Contact us today to learn more. Safina is focused on customised production according USA: 01 708 344 7600 to the manufacturing method and demands, offering [email protected] tailor-made solutions to its customers. Its powders are used in serial production for customers in the electronics industry and for high-end applications such as rocket combustion chambers for the aerospace industry. Inspection methods like sieving analysis, laser diffraction granulometry, dynamic image particle analysis, Scanning Electron Microscopy (SEM), chemical analysis by ICP-OES or EDX, gas content measurement, tap and apparent density/flowability measurements control the quality of the powders. Safina’s background in the precious metals business has given the company extensive experience as a safe, reliable partner in the realm of recycling, striving towards very high purity and very low gas content of materials, which serves to improve the quality of products manufactured. www.safina.cz

FSW is a high integrity, low Leveraging over forty years of Element Six to distortion and environmentally- market-leading PCBN material Mitsubishi Power establishes licensing develop PCBN benign welding technique allowing expertise in cutting tools, Element Six agreement with Aubert & Duval as it the automated production of high- has already worked closely with The tools for EU strength welds. The technique, Welding Institute (TWI) to demonstrate nears launch of new AM business which also works underwater, that PCBN FSW tools offer signifi- friction stir Mitsubishi Power, Ltd., a subsidiary to be capable of fully-integrated is said to offer a combination of cantly extended tool life and superior of Mitsubishi Heavy Industries production – from the development of welding research improved quality, production speeds weld quality in steel. (MHI) Group, Yokohama Japan, and powder and wire materials to metal and cost efficiencies. FSW is already widely used for programme Aubert & Duval, a subsidiary of the AM and product finishing. As part of the RESURGAM manufacturing aluminium mate- High Performance Alloys Division of Mitsubishi Power explains that Element Six, headquartered in programme, Element Six will rials and Element Six explains that a the Eramet group, based in Paris, it possesses proprietary material Didcot, Oxfordshire, UK, part of the develop specialised polycrystal- crucial part of the research project France, have announced a licensing technologies in metal AM, and can Prototype of a gas turbine combustor De Beers Group, reports that it is line cubic boron nitride (PCBN) will be the transfer of FSW technology agreement for the production and optimally prepare raw materials for component (Courtesy Mitsubishi participating as a tooling solutions FSW tools with a range of sizes for into the welding of steel, which report- distribution of metal powders used each application required. It also Power) provider in a European Union welding steels that are required for edly accounts for the vast majority of for Additive Manufacturing. has technologies that significantly (EU) research initiative to scale various marine applications. The €6 global metals production. Success will The agreement is said to pave enhance the performance of powder friction stir welding (FSW) for mass million research project is funded by enable the construction and ongoing the way for the full-scale launch of manufacturing equipment. This with Mitsubishi Power’s proprietary adoption in the shipping industry. the EU Commission and will involve maintenance of larger, stronger and Mitsubishi Power’s AM business, is achieved by incorporating the technologies to enable the provi- RESURGAM (Robotic Survey, leading researchers and shipyards stiffer shipping vessels. which follows the recent creation of company’s specially developed high- sion of powders optimally suited to Repair & Agile Manufacture) from nine European countries. The company brings to the market an AM-Zone® at its Hitachi Works performance gas nozzles into the gas metal Additive Manufacturing. Along is a research programme that Element Six will work alongside its capability to produce reliable, in Ibaraki Prefecture to serve as a atomisation system that produces with the creation of the AM-Zone, was established to improve the a range of groups, including The consistent and long-life PCBN development and manufacturing base metal powder materials by atomising Mitsubishi Power will become productivity of shipyards fabricating Welding Institute (TWI), leading FSW tools for welding of steel – an for the company’s Additive Manufac- inert gas into vacuum-fused metals. involved in all aspects of metal AM new, advanced technology vessels researchers from shipyards, other important competitive advantage turing business. Under the new agreement, Aubert processing, from material develop- and increasing their access to manufacturing industries and that removes barriers for widespread The new facility is equipped with & Duval’s know-how in the composi- ment to final product manufacture. specialist repair and maintenance. academia. industrial adoption of its solutions in powder manufacturing equipment tion and manufacturing of powders www.mhi.com a wide range of applications including and metal AM machines, and is said for AM applications will be combined www.aubertduval.com oil, gas & water pipelines, automotive, aerospace and energy. Abhishek Tanwar, Sales Director for Grits and Distribution at Element Six, commented, “We are delighted to be involved in the RESURGAM initiative as an advanced tooling solution provider. Friction stir welding has the potential to transform the manufacturing and repair of steel structures through better joints, as well as safer and more eco-friendly processes.” “Thanks to their excellent high temperature and hardness properties, our PCBN tools are uniquely equipped to deliver this,” he continued. “The RESURGAM programme is another important step towards more widespread adoption of a welding technique that will significantly improve Element Six will develop polycrystalline cubic boron nitride (PCBN) friction stir productivity and reduce environmental welding (FSW) tools as a participant in the EU research project RESURGAM impact in the shipping industry. (Courtesy Element Six) www.e6.com

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elements (interconnector), was GTP and Plansee HPM components to manufactured by Plansee HPM help produce oxygen on board Mars and Global Tungsten & Powders. GTP has extensive experience Perseverance rover in the production of chromium- based interconnectors for Solid Global Tungsten & Powders Corp OxEon Energy were used in NASA’s Oxide Fuel Cells (SOFC), a related (GTP), Towanda, Pennsylvania, USA, Perseverance Mars rover, which technology. has reported that components successfully touched down on MOXIE is a joint effort of the manufactured for its customer Mars in February 2021. Massachusetts Institute of Tech- OxEon Energy, based in North nology (MIT), NASA’s Jet Propul- Salt Lake, Utah, USA, is a pioneer sion Laboratory, OxEon Energy in solid oxide fuel cell develop- and additional contributors. The ment, energy conversion and 1/200 scale test model travelled for storage. The company developed more than six months on the Mars a ruggedised hermetic Solid Oxide mission. Electrolysis Cell (SOEC) stack to If successful, solid oxide elec- be used with NASA’s Persever- trolysis may be deployed to produce ance mission. The MOXIE (Mars oxygen for propellant oxidant in Oxygen Oxygen In-Situ Utilisation a Mars Ascent Vehicle, and fill an Experiment) on board the rover will oxygen reservoir that could be used produce pure oxygen from Martian for a return mission.

GTP and Plansee HPM supplied atmospheric carbon dioxide (CO2), www.oxeonenergy.com components to OxEon Energy for the by using a process called solid www.globaltungsten.com Solid Oxide Electrolysis Cell stack to oxide electrolysis. www.plansee.com be used with NASA’s Perseverance The component that helps mission (Courtesy OxEon Energy) to divert the gas into the cell’s

FPT Industries explains that FPT Industrial launches R&D project for the overall goal of the project is to alternative fuel in heavy-duty engines advance the understanding of using DME as an alternative to diesel in FPT Industrial, Turin, Italy, a brand engine hardware configuration and the industrial goods sector and of CNH Industrial specialising in the calibration, significantly low NOx and demonstrate clean combustion design, production and sale of power- particle emissions, whilst main- at comparable efficiency levels. trains for on- and off-road vehicles, taining high engine efficiency. FPT Since DME combustion produces marine and power generation appli- has stated, however, that there are practically no particle emissions, cations, has launched a project for still some challenges in the use of a comparably simple SCR system, the development of alternative fuel in DME as a fuel, particularly in terms without the need for a particle filter heavy-duty engines. of the fuel injection equipment. may be enough to comply with FPT Motorenforschung, Arbon, DME has been industrially used strict emission standards. Switzerland, the company’s research for decades, mainly as a propellant The project’s first experimental and development centre, is devel- in aerosol cans as it is non-toxic, data reportedly shows promising

oping the use of DME (Dimethyl- odourless and can be absorbed in results in terms of CO2 reduction, ether, CH3-O-CH3), an alternative the troposphere. From a storage and along with significantly low NOx fuel used in an 11-litre heavy duty refuelling point of view, DME is like and particle emissions, together engine. The centre is one of seven liquefied petroleum gas (LPG): liquid with similar engine efficiency to global R&D locations. Common Rail at very moderate pressure levels. diesel. technology and the HI-eSCR (High The project is funded by Swiss The company states that it is Efficiency Selective Catalytic Reduc- Federal Office of Energy (SFOE) and facing a major challenge with the tion system) were both developed at the test bench is operated at the requirement to reach the European

the Arbon centre. Swiss Federal Laboratories for Mate- CO2 emission targets in 2025 and DME is said to be a suitable fuel rials Science and Technology (Empa) 2030. The use of alternative fuels for compression ignition engines in Dübendorf, Switzerland, where and e-fuels are possible paths to and can be produced from several the company states it has invested addressing these challenges. renewable sources. Its chemical heavily in the infrastructure adapta- www.fptindustrial.com properties allow for, with the correct tions necessary for DME.

Kyocera Corporation to construct Rusal America Alloyed invests in Electro-Thermal new R&D centre expands line of Mechanical Testing machine sustainable, high- Japan’s Kyocera Corporation Center, which develops simulation Alloyed (formerly OxMet Technolo- turing processes, including AM. While has announced that it will begin and evaluation technologies. performance gies), Oxford, UK, reports that it has many customers have come to us construction of a new research and Current R&D programmes aluminium invested in an Electro-Thermal since we installed the ETMT machine development centre in January 2021 include 5G smartphone technolo- Mechanical Testing (ETMT) machine to take advantage of its superior at its Kokubu campus in Kirishima gies, electronic and semiconductor powders and is one of the only private compa- attributes, it is often a gateway for City, Kagoshima, Japan. components used in IoT devices, An architect’s rendering of the new nies globally to have this technology them to then take advantage of the Kyocera has executed a loca- and key components for new smart R&D centre that will be constructed Rusal America, Rye Brook, New York, in-house for the benefit of its array of services that Alloyed can tion agreement with the mayor of energy technologies, such as cell at its Kokubu campus (Courtesy USA, has expanded its aluminium customers. offer for advanced metal manufac- Kirishima City for the new centre, stacks for Solid Oxide Fuel Cells Kyocera Corporation) product offerings to include a range The £300,000 investment in the turing projects.” which will focus on new innova- (SOFCs). Intellectual property of aluminium powders suitable for ETMT machine, which is located Guetard added, “At Alloyed, we tions in the fields of information and developed on the campus is said to Additive Manufacturing applications. in its metal research, testing and have equipped the ETMT with a state- communications, environmental have found a wide range of other new products, promoting factory auto- Its new powders portfolio is characterisation laboratory in of-the-art digital image correlation preservation, and smart energy. applications such the automotive, mation and improving manufacturing comprised of four traditional Al-Si Oxford, is said to make Alloyed a (DIC) system, which allows us to opti- The Kokubu campus currently aerospace, medical and healthcare efficiencies. The company states that based casting alloys and five specialty one-stop shop for a range of metal cally measure strain on the sample houses an innovation hub and three fields. it will position the new facility specifi- alloys designed for use in the aero- tests that would have previously only during testing. The machine is well strategic R&D groups: Kyocera’s Through greater collabora- cally as an incubator for open innova- space and automotive industries, been possible through a number of suited for miniature test specimens, Monozukuri R&D Laboratory, which tion among these R&D operations, tion, sharing technical information as well as more broadly in general different testing companies. which allows us to obtain site- focuses on advanced material tech- Kyocera hopes to establish a new for human resource development and industry. The ETMT machine can perform specific mechanical properties from nologies; its Production Technology platform to accelerate development networking with inventors outside of The portfolio includes 100% tensile and compression, creep (also large parts such as forgings.” Division, focusing on manufacturing and production efforts, with compre- Kyocera. pre-alloyed and fully metallic called stress-rupture) and fatigue “We have also found it very valu- process innovation; and its Analysis hensive support for manufacturing https://global.kyocera.com/ powders that exclude any ceramic- or tests. Tests can be undertaken in able in measuring the properties of nano-inclusions. Its RS-230 grade air, vacuum or foreign gases such fine additively manufactured struc- is a heat-crack resistant Al-Cu alloy as argon. The temperature of the tures like lattices or thin walls. The with high-strength stability up to sample being tested is controlled machine is extremely versatile and 250°C. The RS-553 grade is a novel by the Joule effect, meaning that allows for an array of tests to be aerospace Al-Mg-Sc alloy, with temperatures in excess of 1000°C undertaken under one roof, so any optimised scandium content, that can be attained. The ETMT machine interested parties can approach us ™ The most advanced acoustic resonance delivers comparable properties at can also quickly heat and cool to discuss the possibilities and also SMARTTEST inspection systems available anywhere. a lower cost than similar Al-Sc AM samples, affording the ability to cycle to assess what else we can help with alloys. the temperature or perform in-situ through Alloyed’s unique stack of The powders are atomised from heat treatments. technologies for the manufacture of the company’s ALLOW aluminium “While the ETMT machine adds advanced metal components both feedstock, said to have a carbon hugely to our in-house technology by additive or traditional means,” he footprint 75% lower than the global portfolio used on behalf of an array concluded. industry average (smelter scope 1 of customers working on exacting https://alloyed.com & 2 emissions). All powders come AM and non-AM metal product with a third-party certified carbon applications, it is the combination of certificate to promote transparency the technology with the vast experi- and accountability. ence of the Alloyed team that is the “From primary aluminium and real strength,” stated Gael Guetard, foundry alloys to billets and wire rod, Alloyed’s Rapid Alloy Research Rusal America is a trusted supplier Centre Director. with a reputation for delivering “Alloyed’s unrivalled expertise unmatched high-quality, low-carbon lies in using advanced metallurgy, aluminium products backed by the latest simulation techniques, customer and technical support that and a profound understanding of the is second to none,” stated C. Brian factors that drive alloy performance,” ACHIEVE Hesse, president and CEO of Rusal he continued. ADVANCEDMATERIALSOLUTIONS.COM America. “The company focuses on multi- NEXT LEVEL RESULTS 602.442.1899 “We are excited to deliver the scale materials and multi-physics Alloyed has added an Electro- // BETTER DEFECT same to customers new and existing modelling, prediction and analysis of Thermal Mechanical Testing machine // LOWER INSPECTION COSTS DETECTION LOCATIONS through our new line of innovative AM fatigue and failure (an area enhanced to its metal research, testing and // MAXIMUM THROUGHPUT // FEWER FALSE REJECTS & PRODUCTIVITY PHOENIX, AZ // CINCINNATI, OH // CELAYA, GTO powder alloys,” added Hesse. by the ETMT machine), and the characterisation laboratory in Oxford www.rusalofamerica.com optimisation of complex manufac- (Courtesy Alloyed)

ments of Nadcap accreditation, Isostatic Toll Services Bilbao receives whose credit is shared among all Nadcap accreditation for heat treating the people that with passion and competence made this possible; the Isostatic Toll Services Bilbao SL mitigation activity in the industry. ITS US sister company, the manufacturer (ITS Bilbao), Spain, recently received Bilbao, sister company of Isostatic of the HIP unit, the customers, our Nadcap accreditation for its heat Toll Services (ITS), Olive Branch, specialised consultants, and our key treating services. Nadcap provides Mississippi, USA, is equipped with people on-site. One word among test, independent certification for manu- an AIP52 HIP unit, with a hot zone many: teamwork.” facturing processes for the aerospace diameter of 1100mm and depth of In addition to its Nadcap and Industry. ITS Bilbao opened a new 2500 mm at 103 MPa, the AIP52 is ISO 9100 achievements, ITS Bilbao Hot Isostatic Pressing (HIP) facility capable of processing large compo- has received special approval from analyze, in January 2020, in Abanto Zierbena, nents, such as engine blades, vanes Rolls Royce, ITP, Safran, and Pratt Biscay, Spain. and integral rings used in the aviation & Whitney. Honeywell Aerospace’s The company explains that with industry. The investment for a second approval process is said to be over fifty subscribers among the identical unit in Bilbao is said to have currently ongoing. The AIP 52 unit characterize most relevant OEMs, the Nadcap already been confirmed and will be in can currently HIP parts in aluminium, accreditation is seen as the refer- operation by October 2021. titanium, and nickel alloys up to ence in developing industry-wide Fernando del Val, Plant Manager 1250°C. audit criteria for special processes in ITS Bilbao, commented, “It is ITS explains that its long-term and products, and the cornerstone in indeed a remarkable achievement to strategy is to deploy a solid and Validating Powders, Feedstock & Products quality supply surveillance and risk directly meet the stringent require- widespread network of service centres for big-size toll HIPing. Since 1945, NSL Analytical has been trusted to verify the highest standards of quality, Fernando del Val added, “HIP is performance, and safety. NSL supports innovation by testing powder metal, feedstock, our core competence. Through our prototype designs and final products for the Powder Metallurgy Industry. special relationships with AIP Inc, we master the complete process: from g Powder Characterization — static and dynamic flow, density, design to operating HIP units. Nobody particle size distribution, particle shape and moisture content else on the planet can combine U2/ U3 stamp and Nadcap. We are keen g Surface Area — particle size, shape, roughness and porosity to follow ambitions, both in terms of g Material Composition — chemical analysis of major and trace geographical coverage and hot zone level elements for R&D and specification conformance size. When there is a solid business plan, we are ready to invest.” g Validate Metal Printed Parts — metallurgical evaluations, Isostatic Toll Services Bilbao has received Nadcap accreditation for its heat www.isostatictollservices.com mechanical testing, microstructure and failure analysis treating services (Courtesy ITS Bilbao) www.isostatictollservices.eu g Powder Studies — alloy development and powder re-use

Visit nslpowder360.com to learn more! (NNS) Hot Isostatic Pressing (HIP) The increased R&D budget will MTC Powder materials. be utilised to focus on additional Solutions partners MTC PS explains that as more material and process development with Swerim companies are starting to explore in collaboration with companies who NEW Tech Talk Webinars the benefits that NNS HIP can offer, are seeking to take their components to expand R&D it sees an increasing demand for to higher levels of performance and In this webinar series by NSL Analytical Services, scientific experts discuss topics capabilities application-specific development reliability. that are important to you: projects, where the focus is to either “Staying in the forefront of PM extend the operational window or NNS HIP developments has always gRelevance of Metal Particle Surface Area in Additive Manufacturing MTC Powder Solutions (MTC PS), increase the lifetime of customers’ been a cornerstone in MTC PS and gAvalanche Rheometry for Metal Powder Flow Characterization Surahammar, Sweden, part of components. we can gladly announce that not gMeasuring Density of Additively-Manufactured Materials Metal Technology Co Ltd (MTC), In addition to having one the most only have we increased the testing gIssues and Insights Regarding Particle Size Analysis has signed an agreement with advanced laboratories for advanced capabilities, but also increased leading metals research institute material testing/characterisation, the R&D budget for 2021 drasti- Visit nslanalytical.com/webinars to register now or watch any past sessions! Swerim, Luleå, Sweden, to expand Swerim also has great knowledge cally,” commented Tomas Berglund, MTC PS’ testing capabilities in Powder Metallurgy materials and Application Development Manager at in research and development processes, making this agreement an MTC PS. projects related to Powder excellent fit with MTC PS states the www.mtcpowdersolutions.com Trust | Technology | Turnaround Metallurgy, near-net shape company. www.swerim.se/en 4450 Cranwood Parkway, Cleveland, OH 44128 ASME NQA-1 877.560.3875 | ISO/IEC 17025 COMPLIANT

Technical trends in metal-cutting tools: An overview of ongoing innovation in one of PM’s key markets

Cutting tools for metal processing applications represent one of the primary markets for the Powder Metallurgy industry. Here, PM technology makes it possible to produce cutting tools with complex geometries to near-net shape, a feat not possible using conventional manufacturing methods. Despite the basic technologies of metal-cutting tools having existed for several decades, tool manufacturers continue to introduce new products which can provide substantial benefits. In this article, Bernard North, North Technical Management, LLC, overviews developments in materials, design and software that are driving innovation in this important sector of PM.

Tools for the machining of metals tooling, with an approximate date of namely commoditisation, is occurring have, in one form or another, been first significant commercialisation. to some extent in some product and around ever since humankind first From Table 1, it is clear that most market areas. However, the tooling made metallic objects. By the early of the key technologies are already industry manages to maintain a high stages of the industrial era, most several decades old, and, indeed, an degree of innovation across most of its tooling was made from some form of expected outcome of that situation, product areas [1], and the purpose of hardened steel, and the basic types of tools – turning, milling, and drilling, each with various sub-categories, became clearly delineated by their different geometries. The single major advance, which changed almost everything for the tooling world, was the 1926 inven- tion of hardmetal, also known as cemented carbide, or just ‘carbide’. Over the next several decades, a torrent of innovations occurred which increased the performance and/ or application range of hardmetal tooling, or else provided alternatives with - in some applications - even better performance. A selection of the most modern cutting tools are shown in Fig. 1. Table 1 lists the most important Fig. 1 A selection of modern metal-cutting tools (Courtesy Mitsubishi developments in metal-cutting Materials)

Development Major application demand for products exceeds effective Cutting capacity unless it is expanded by edges ‘Straight Grade’ (WC-Co) hardmetal Late 1920s 4 reducing floor-to-floor times in ‘Alloy Carbide’ (WC-Ti/Ta/NbC-Co) hardmetal 1930s machining.

‘White’ ceramics (Al2O3) Early 1940s From the tooling manufacturer’s point of view, the simple fact is that cutting Mechanically clamped (as opposed to brazed) Stable 1950s they have a lot of very capable compet- hardmetal inserts by reinforced geometry itors, most of whom are working hard Moulded chipbreaker indexable hardmetal inserts Early 1960s to gain a greater market share by Tangential Submicron grain size ‘straight grade’ hardmetals 1960s offering better products and services Strong insert to their customers. Tooling manu- ‘Black’ ceramics (Al2O3-TiC) 1960s facturers develop new, and improve Polycrystalline diamond (PCD) Late 1960s existing, products through their own Chemical Vapour Deposition (CVD) on hardmetal Smooth cutting Early 1970s staff’s creative efforts, by working in inserts partnership with their equipment & with high positive rake angle Polycrystalline cubic boron nitride (PCBN) inserts Mid 1970s process suppliers, and with end-users for the testing of new developments. ‘Solid carbide’ round tools 1970s Fig. 2 Advanced macrogeometry insert from Iscar Metals Group (Courtesy Iscar Metals Group) Finally, machine tool builders Functional gradient alloy carbide hardmetal inserts 1980 play a critical role in consumable Physical Vapour Deposition (PVD) round tools 1980 tooling development and applica- TiCN-based cermet inserts Early 1980s tion, in a symbiotic relationship with Silicon nitride/SiAlON inserts Early 1980s carbide tooling manufacturers and Metal Injection Moulding (MIM). Addi- etry or coating. By controlling the development allows higher metal end-users. Higher speed and/or more tive Manufacturing should also find dimensions of edge preparations removal rates and/or tool life, and can Physical Vapour Deposition (PVD) indexable inserts Mid 1980s powerful lathes, milling machines, a role in this trend. Fig. 2 shows an within tighter dimensional limits, also improve part surface finish. Al2O3-SiC whisker ceramics Late 1980s or machining centres enable the use example of one such insert. a corresponding improvement in Through coolant solid carbide drills Early 1990s of modern tooling at high speeds The driver of this trend for the performance consistency will be CNC-enabled non-ANSI/ISO turning Modular (carbide tip, steel body) round tools Early 1990s and metal removal rates, and in turn, tooling manufacturer is to be able achieved. inserts higher performance tools demand to offer more complex geometries Another development in edge Most standard (and some non- Table 1 History of key metal-cutting tooling developments and the approximate more powerful and capable machines. while avoiding high grinding costs, preparation is the use of deliber- standard) metal-cutting inserts years of their initial significant application In addition, some modern tooling and in some cases to produce tooling ately-different hone dimensions conform to the American National geometries are only enabled by geometries which could not be on different portions of the cutting Standards Institute / International multi-axis CNC machine tools. When manufactured even with grinding. edge, an example of which is shown Standards Organization (ANSI/ISO)’s end-users purchase new machine For the user, these tools offer a in Fig. 3. By having a smaller hone convention, wherein a series of letters the present article is to review some From the tool user’s point of view, tools, the transaction commonly larger number of cutting edges on the portions of the cutting edge designates the insert’s physical shape of the more important technical they are under continuous pressure includes both part quality and cycle per insert, combined with a posi- which are ‘buried’ in the workpiece and dimensional tolerance levels, trends. to reduce the cost of machining and time targets, and to meet those tive cutting action and a moulded during cutting (and which are while numbers indicate major physical Those manufacturers able to test improve the dimensional tolerances often requires the latest tooling to be chipbreaker, and in some cases more under compressive stress), cutting dimensions. For simple metal-cutting and implement tools which take or surface finish of machined parts. specified. secure mechanical clamping to the forces are lower, with consequently operations these usually suffice, but if advantage of these trends in appro- If using more advanced tooling toolholder. reduced plastic deformation and multiple operations are needed, one priate machining applications can allows them to do this then they are, heat generation, while the hone or more tool change operations are realise heightened competitiveness of course, strongly incentivised to Technical trends in metal- Precision microgeometries at the depth of cut line is larger, typically required, which increase the through cost savings, productivity implement such tooling using highly cutting tooling While some tools have ‘up-sharp’ giving higher tool strength where machining cycle, or floor-to-floor time and capacity increases, and in some productive machining parameters. cutting edges, and some ceramic it is needed. Properly applied, this of the process. cases, quality improvements. Furthermore, if the total cost of Advanced macrogeometries inserts have ground ‘T-lands’, the machining is properly considered, Metal-cutting carbide inserts with vast majority of tools have a honed including the depreciation cost of chipbreaker geometries on one or two edge which, at the cost of increasing What drives and enables machine tools, and operating costs sides have been around for several cutting forces a little, is stronger, technical advances in for coolants, direct and indirect decades, while grinding is used to in effect ‘pre-wears’ the tool for Variable edge the metal-cutting tooling labour, utilities, building space and create more complex geometries. better part dimensional stability, and preparation industry? workpieces, the cost of consumable There has been a growing trend improves coating adhesion at the tooling is actually quite a low in recent years for more complex cutting edge. Because edge prepara- Several economic and technical percentage of the total. However, ‘moulded’ (not ground, or with tion is not visible to the naked eye, factors are at play in the tooling what tools are used, and under only simple grinding steps) insert and is not usually openly specified, it area which either enable what machining parameters, has a geometries which cannot be created is easy to overlook the importance of Hone technical advances, or drive their dominant effect in leveraging those using simple uniaxial pressing to form this tool characteristic. rub zone commercialisation as products or other costs to maximum effect. the green parts prior to sintering, However, performance-wise, it can services and thus encourage their This is especially true in capacity- and must be made using CNC green be just as important as more visible Fig. 3 Tool edge with variable edge microgeometry (left) and diagram of use. constrained situations, where the machining, multi-axis pressing, or characteristics such as macrogeom- variable edge microgeometry (right) (Courtesy Conicity Technologies)

sharp or have a very small hone. The disadvantage of PVD versus Chemical Vapour Deposition (CVD) coating, namely that it is difficult to deposit adherent thick coatings or coating compounds with high chemical stability, has been minimised through developments in power supplies and controls; as a result, smooth, adherent (and, if desired, thick) coatings with a controlled stress state and high wear resistance are now available (Fig. 5). These advances allow modern PVD-coated tools to Dynamometer run at higher speeds on difficult materials. Cutting tool - PCBN insert Innovative ceramic materials Fig. 4 Non-ANSI/ISO Inserts for multiple turning operations produced by Ceratizit (left) and Sandvik Coromant (right) (Courtesy Ceratizit and Sandvik Coromant) Ceramic tools are primarily used to machine three (very different) classes of workpiece material: cast Workpiece irons, hard steels and nickel-base Non-ANSI/ISO standard inserts to perform multiple operations, thus uitous on solid round high-speed superalloys. Their main advantage have for many years been common eliminating one or more tool change steel and carbide round tools, and over cemented carbides is their in threading, grooving or cut-off operations and reducing floor-to- is also very common on inserts. higher speed capability. operations, and many of these inserts floor times for complex turning oper- Its fundamental advantage is that, The early Al2O3-based tools, can also be used for simple turning ations. This is an excellent example being deposited at low temperatures due to their low toughness, are operations. of the technical synergy which exists below the annealing temperature primarily used for non-interrupted Recently, some manufacturers between consumable tooling and of the substrate, the compressive turning of cast iron and hard have gone a step further by intro- the machine tool it is mounted on. grinding stresses which strengthen steels. The later development of ducing proprietary geometry inserts, Examples of such inserts are shown the substrate are maintained, Si3N4/SiAlON and SiC whisker- along with the requisite toolholders in Fig. 4. and, in addition, the stress state reinforced Al2O3 greatly extended and CNC programs which, when used of the coating itself is generally the application range of ceramics on a turn-mill machine, take advan- Advanced PVD compressive. due to their higher toughness and Fig. 6 Superhard insert developments. Top; multiple corners with precision tage of the machine’s geometrical Physical Vapour Deposition (PVD) This results in the tool edges thermal fatigue resistance, and microgeometry, middle; hard turning testing, bottom; chipbreakers (Courtesy freedoms and allow a single insert coating has become almost ubiq- being stronger, even if they are new ceramics, including in solid Element Six and Seco Tools) end-mill form as well as prismatic inserts, continue the trend to ever higher cutting speeds and metal Advanced geometry solid round more precise, added axes, and removal rates. tools integrated finished tool design High-speed steel and cemented with grinding programs, it has Superhard (diamond and cubic carbide solid round tools – usually become possible for tool designers boron nitride) tooling PVD coated – are used for the to realise ever more sophisticated Superhard tooling has continued majority of small diameter hole- tools in practice. to gain its share in the metal- making and milling operations. Fig. 7 (top) shows a grinding cutting tooling market due to Integral cooling holes allow coolant operation to put a full-length both workpiece mix shifts (the use on machines equipped with geometric feature behind each use of more light alloy and non- through-the-spindle coolant, and of the cutting edges of a helical metallics, in particular, encourage keep cutting temperatures low as end mill. Fig. 7 (middle) shows polycrystalline diamond (PCD) well as flushing out chips. a prize-winning example of a use), and developments in the The degree of geometrical multi-function special tool able tools themselves. Fig. 6 illustrates complexity and differentiation to combine multiple operations some important developments in which can be created is quite (drilling, reaming, thread milling) polycrystalline cubic boron nitride remarkable, from what is essen- into a single tool. Fig. 7 (bottom) (PCBN) which are especially appli- tially a simple cylinder of hard shows a modern ball-nose end mill Fig. 5 Microstructural cross-section of advanced PVD-coated honed milling insert (left), and the milling inserts in the cable to the hard turning of ferrous material, using modern grinders. incorporating several advanced cutter body (right) (Courtesy CemeCon AG) materials. As these grinders have become geometrical features.

Quick-change modular round tools Solid carbide round tools are almost ubiquitous, and are preferred for many operations, but they do have two disadvantages: high-value material is used for the entire tool, including the ‘holder’ end which is not subject to high heat and wear, and, due to their high cost, tools are typically reconditioned several times, with consequent extra complexity for inventory, shipping, and receiving management. For these reasons, modular round tools, especially drills, have become increasingly popular, and offer the same geometric cutting Fig. 8 A KenTIP™ FS modular drill by Kennametal (Courtesy Kennametal Inc.) action, coolant availability and materials science features as solid tools (Fig. 8). Quick-change end mills are less software program. The software, Metal-cutting tooling trends others may be, depending on the common than their drill counter- in turn, outputs a bill of materials for end-users in the Powder composition of the workpiece listing recommended tools, and with material and the type of machining parts. This is primarily because many Metallurgy industry end mills are used for operations recommended machining param- operation required. For a thorough requiring close to their entire cutting eters. If desired, the bill of materials overview of PM part machining Powder Metallurgy parts represent length, and because the heavy side can be linked to purchasing practices, see [2]. only a small proportion of the loading that end mills experience in functions. Three examples which show total metallic components being use poses a more difficult design and As well as being a timesaver for the benefit of applying modern machined, and few tools are devel- manufacturing challenge to solve all parties, the software also helps tooling for real operations on PM oped specifically for the PM industry. than it does for drills, which primarily to increase the speed of adoption components are shown in Figs. Because PM parts are near-net experience axial and twisting loads. of newer, more high-performance 10–12. Fig. 10 shows how selecting shape, tooling developments aimed However, some recent modular end tooling, with consequent benefits for an optimum microgeometry (hone) at heavy roughing are unlikely to mills have solved the latter problem both the tool manufacturer and the improves hole size uniformity and be applicable to PM machining, but and offer similar performance to user. surface finish in a boring operation, their solid carbide counterparts (Fig. 9).

Software for tooling and parameter selection Historically, tool selection has been guided by a combination of existing practice, advice from tooling engineers, and the grade, chipbreaker, and starting cutting parameter sections in tool manufacturers’ paper catalogues or on their websites. While that works, it can be quite time-consuming, even for very skilled and experienced engineers. In the last few years, some manufacturers have condensed all this and other knowledge into ‘expert systems’ whereby the end-user, machine tool engineer, or even the tooling company’s own experts Fig. 7 Top; Grinding operation on solid carbide tool, Middle; Multifunction input the workpiece material, blank special solid carbide tool, Bottom; Modern solid carbide ball-nose end mill and final dimensions, machine tool Fig. 9 Modern modular carbide end mills from Kennametal (left) and Mitsubishi Materials (right) (Courtesy Kennametal (Courtesy Rollomatic, ANCA / Arch Metal Tools, and Kennametal Inc.) power and tool connections into a Inc. and Mitsubishi Materials)

52 Powder Metallurgy Review Spring 2021 © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd Spring 2021 Powder Metallurgy Review 53 Hone size vs ID 6.09 Upsharp 0.018 mm 0.03 mm 6.08 0.03 mm

6.07

6.06 Upsharp

6.05 Technical trends in cutting tools | contents | news | advertisers | events | website | e-newsletter | | contents | news | advertisers | events | website | e-newsletter | Technical trends in cutting tools Inside Diameter (mm) 6.04 0 5 10 15 20 Number of Holes Increased productivity with new ceramic grades Hone size vs ID Hone size vs ID 6.09 Upsharp I.D. Surface Roughness Conclusion 6.09 Upsharp 0.018 mm 0.03 mm 64 6.08 0.018 mm Upsharp 0.03 mm 0.03 mm 0.4 0.018 mm 18 µm hone 6.08 Despite the basic technologies of 6.07 0.03 mm 0.35 0.03 mm 63 0.3 metal-cutting tooling being now 6.07 6.06 Upsharp 0.25 several decades old, tool manu- 62 6.05 0.2 facturers, through both their own Insert: Ceramic 6.06 Hone size vs ID Inside Diameter (mm) Upsharp 61 Insert: Carbide 6.09 Upsharp 6.04 0.15 Speed: vc = 213 m/min 0.018 mm 0 5 10 15 20 development efforts, and advances Speed: vc = 76 m/min 6.05 0.03 mm 0.1 Feed: fz = 0.1 mm/rev&tooth 6.08 Number of Holes 60 0.03 mm in the technology of their equipment Feed: f = 0.1 mm/rev&tooth 0.05 Coolant: dry z Inside Diameter (mm) Coolant: dry 6.07 6.04 I.D. Surface Roughness 0 supplier partners, continue to intro- Removed: 871mm³ Surface Roughness µm)(Ra 59 0 5 10 15 20 Upsharp 2 13 18 Removed: 871mm³ 6.06 duce new products which can provide 0.4 Upsharp 0.018 mm 18 µm hone Flank (µm)Wear Number of Holes 0.35 0.03 mm Number of Holes 30 µmsubstantial hone benefits versus older 58 6.05 0.3

Inside Diameter (mm) 0.25 tooling. Manufacturers, whether they Hone size vs ID 6.04 Upsharp I.D. Surface Roughness 57 6.09 0 5 10 15 200.2 0.018 mm are machining forged, cast, or PM 0.15 0.03 mm Number of Holes Upsharp 6.08 0.1 parts, who test and implement such 56 0.03 mm 0.4 0.018 mm 0.05 18 µm hone I.D. Surface Roughness 0.03 mm tools in appropriate applications, 6.07 0.35 0 Surface Roughness µm)(Ra 55 0.3 Upsharp 2 13 18 can realise significant cost savings, 6.06 0.4 0.018 mm Upsharp Number18 of µmHoles hone 30 µm hone 0.35 0.25 0.03 mm productivity and capacity increases, 6.05 0.3 0.2 Fig. 12 Hard turning speed improvement achieved using a ceramic insert

Inside Diameter (mm) 0.25 Fig. 10 The importance of edge preparation to hole dimensional uniformity [2] and, in some cases, part quality 0.15 6.04 0.2 (Courtesy Tenneco Powertrain) 0 5 10 15 20 benefits. 0.15 0.1 Number of Holes 0.1 0.05 0.05 0 I.D. Surface Roughness 0 Surface Roughness µm)(Ra Surface Roughness µm)(Ra 2 2 13 18 13 18 Upsharp Author 0.4 0.018 mm while Fig. 11Number shows18 of µmHoles an hone improveNumber of- Holes Firstly, most 30as-sintered µm hone PM steels 30Secondly, µm hone many PM materials 0.35 0.03 mm ment in hole cylindricity, achieved have open porosity, and this effectively include machinability aids dispersed 0.3 Bernard North William Shaffer References 0.25 by transitioning from a straight precludes the use of aqueous coolant through the microstructure. Such 0.2 North Technical Management, LLC Conicity Technologies 0.15 flute to a straight/helical flute drill, in their machining, due to the internal aids were introduced when the avail- 0.1 Greater Pittsburgh Area [1] ‘Global Trends in the P/M Hard and which also permits higher corrosion and part contamination that able metal-cutting tools were far Toni Leyendecker and Christoph 0.05 Pennsylvania, USA Materials Industry’, by C Gey, J 0 Schiffers Surface Roughness µm)(Ra metal removal rates. Fig. 12 shows would result from aqueous coolant less wear-resistant than those on the 2 13 18 CemeCon AG Bitler, D Banerjee, J Goldsmith, J Number of Holes a flank wear reduction,30 µm hone despite use [2]. Several of the developments market today. It may be that using [email protected] Kohlscheen and M Wolf, as presented almost three times the cutting in this article reduce cutting tempera- the most modern tools, under appro- Ryan Lake at the 19th Plansee Seminar, 2017 speed, in a hard turning application tures by having a more positive priate parameters, could allow such Acknowledgements CemeCon Inc. achieved by utilising a modern cutting action, and/or enhance the additives to be eliminated. If this, [2] ‘Machining of Powder Metallurgy ceramic insert. cutting edge through the use of more in turn, improved the PM material’s Bernie McConnell and Kari Materials’, revised and updated by Two peculiarities of many wear-resistant substrates or coatings. mechanical properties, then it may The author wishes to thank the Carpenter D Christopherson, published in the PM parts, with respect to their These developments encourage the allow the redesign and lightweighting following colleagues for the provision Greenleaf Corp ASM Handbook, Vol. 7, Powder Metal- of images and/or helpful discussions: machining, are worthy of mention use of dry machining and thus may of PM components and/or improve Gerry Pyne lurgy 2015, pp. 395–404 as regards the potential impact of be especially valuable for many PM their performance competitiveness Christoph Gey Element Six higher performance tooling. machining operations. versus forged parts. Kennametal Europe GmbH Eric Schwarzenbach Colin Andrews Rollomatic Inc. MMC Hardmetal UK Ltd. TIR improvement with helical/straight fluted tool Denis Christopherson, Thorsten TIR improvement with helical/straight fluted tool Uwe Schleinkofer Upmeier, and Vicki Urban 2.8 TIR improvement with helical/straight2.8 fluted tool Ceratizit Group Tenneco Powertrain 2.82.6 2.82.6 2.62.4 2.62.4 2.42.2 2.42.2 2.22.0 2.22.0 TIR in µm in TIR TIR in µm in TIR 2.01.8 2.01.8

TIR in µm in TIR 1.6 TIR in µm in TIR 1.6 1.8 Straight only Helical/Straight 1.8 1.61.4 1.61.4 Straight only Helical/Straight 1.4 20 40 60 80 100 1.40.00 0.05 0.10 0.15 0.20 0.25 20 40Cutting Speed60 vc 80 100 0.00 0.05Feed 0.10Rate per0.15 Tooth ft0.20 0.25 in m/min Cutting Speed vc Feed Ratein mm/rev per Tooth ft in m/min in mm/rev

9mm Straight fluted 9mm Helical/Straight fluted 9mm Straight fluted 9mm Helical/Straight fluted

Fig. 11 Effect of drill design on hole cylindricity and metal removal rate (Courtesy Tenneco Powertrain)

Fatigue data for PM steels: How the world’s largest PM part producer is facing the challenges of data generation and organisation

Data on the material properties of Powder Metallurgy steels, in particular static and cyclic strength data, is crucial for end-users to have confidence in the production of highly loaded applications. Access to such data also enables the effective use of commercial fatigue simulation software. GKN Sinter Metals, the world’s largest producer of structural PM components, has grappled with the multiple challenges associated with generating, storing and retrieving such data. Markus Schneider, Robert Maassen, Dennis Wawoczny and Christos Radis, GKN Sinter Metals Engineering GmbH, Radevormwald, Germany, share their insight into this ongoing effort, which could offer significant opportunities for the wider use of PM.

Digitalisation, Industry 4.0 and the testing will be necessary, resulting a relational database with a matching 16 – 19 NOVEMBER 2021 Digital Twin are buzzwords often in extra costs. For all industries, Database Management System FRANKFURT / GERMANY used throughout the media when well-structured material data can (DBMS) is usually used. This kind of talking about the future of industry. be the differentiator to outperform DBMS exhibits the following – or even As of today, industrial companies competitors. For material databases, more – functionalities [1]: and research institutes can lack IT support for their material data. This Enabling data is often decentralised, stored in a vast number of spreadsheets or saved in many different data the impossible! systems, for example, making it impossible to systematically process and analyse its properties. We know that additive manufacturing offers Because of this, only a limited undreamed-of potential. Only, however, if all the number of employees, as a result upstream and downstream processes are taken of their working experience, have into account – from design to material and qual- full knowledge of the materials ity assurance. used and where to find the material data needed. This knowledge is, Does your technology contribute here? therefore, inaccessible to most. This If so, do secure your space in Frankfurt. can be even more of a challenge if specific material data is used and formnext.com organised by CAE-engineers and requested by salespersons – both Where ideas take shape. can have different key figures. #formnext Without the proper organisation of data, knowledge might be lost in Fig. 1 GKN Sinter Metals’ Bruneck facility is just one of many plants within the long run, or avoidable double GKN Sinter Metals that serves the global automotive and engineering sectors

1. Data definition magnetic properties, as well as data and exact derivations) is needed to Data needs a structure and clear for the heat treatment of, or informa- save testing capacity. Later, we will nomenclature to avoid redundancy in tion on, processing or purchasing the see a simplification of the Haigh the dataset, or, at least, some kind required materials. damage line (mean stress sensitivi-

of built-in control to point out similar Since the process of selecting ties M1=M4=0), a used similarity in inputs. engineering materials is a complex terms of the logarithmic standard

task, because there are so many deviation of the strength ss (material 2. Data update possible solutions, there are applica- scatter) and a few other assump- Data needs to be inserted, modified, tions that help with decision making tions, which are beyond the current or deleted. by comparing materials according knowledge of sintered PM steels. to chosen key parameters. Since 3. Data retrieval commercial material databases only The saved data must be acces- represent mean values for given PM database approaches sible directly for use or for further materials, there is usually an appli- processing by another application cation to include experimental data. The attempt to store, organise, (e.g, CAE-system). For example, there may be a special systematise and input material production route for a material that properties is not a new idea unique 4. Data administration might be strongly influenced by an to the Industry 4.0 community. Monitoring and managing of users applied heat treatment, making it In-house generated material that access the data in the DBMS, necessary to consider this in the properties are costly and their recovery of data after unforeseen development of a new product. The ability to be transferred to other events like system failure and development of new products usually members of an organisation creates maintaining data integrity. Material starts with computer aided (CAx) a competitive advantage. Moreover, databases and DBMS’s are readily techniques. it is only possible to choose a available from different companies, All commercial databases come requirement-satisfying material for example MATPLUS GmbH offers with an interface or export manage- and manufacturing process if a StahlDat SX, Key to Metals AG offers ment tool to make the material wide overview about the generated Fig. 2 VVT components mass-produced by GKN Sinter Metals for use in combustion engines TotalMateria and Ansys Inc. offers dataset accessible for simulation data can be achieved within a short Granta Design. These databases software. Depending on the simula- time frame. The training of younger utilise a wide spectrum of mate- tion software used, this step fits into or inexperienced members of the rial datasets depending on which the product development workflow, organisation and the benchmarking

components of the databases are making it easy to run multiple simu- with other competitive technologies, beginning in 2000 and with the and the ultimate tensile strength su The difficulty lies in the difference

purchased. lations at once. in terms of material properties, will official launch at the 2004 PM World for a survival probability of Ps=50%. between model parameters and This article describes a way be simplified. Congress in Vienna. Partly, the Assumptions or further data from material properties. The commu- Users have the opportunity to to organise and generate often- A few database approaches development of the GPMD was moti- extra sources are needed to complete nicated mechanical properties, access material data on steel, nickel, requested material properties of have been achieved within the vated by a report from the Boston the dataset. physical properties and fatigue titanium, aluminium and many other sintered Powder Metallurgy steels Powder Metallurgy community. The Consulting Group, funded by the The GPMD is focused on the properties of the GPMD are those for speciality alloys. Usually, composite beyond the common standard Computer Aided Selection of Iron MPIF, although the EPMA had identi- properties of ferrous and non-ferrous which derivation is fixed and could be and natural materials, such as wood, procedures. A special focus is on the Powders (CASIP) was developed fied a similar requirement at around materials used in engineering, based replicated everywhere. Usually, it is fibres or minerals, are also available. accessibility of the generated data to by Sweden’s Höganäs AB to store the same time. Data were shared by on key variations in processing believed that material properties and These datasets are extracted either feed a commercial fatigue software: and to organise static material EPMA, MPIF and the Japan Powder conditions such as heat treatment model parameters are the same or from international standards (ASM, here, nCode inside Ansys. It will be properties such as the 0.1% offset Metallurgy Association (JPMA) and sintering, and includes fatigue quite similar. The correct derivation

ISO, etc), proprietary manufacturer shown that the existing datasets from yield strength sy, ultimate tensile and three categories were defined: data on some grades. The database of material properties is described

datasheets, technical reports or common standards are insufficient strength su, fracture strain ef and mechanical properties, physical includes properties of PM steels in a few standards – for example, for peer-reviewed papers, leaving the for a modern fatigue assessment Vickers hardness H in a fully facto- properties, and fatigue properties [3]. and stainless steels from 6.4 g/cm³ tensile tests. user with a wide range of mechanical that has a focus on static and cyclic rial manner as a function of the Fatigue properties were clustered upwards, powder forged steels and However, modern fatigue assess- properties (including static and strength. sintered density r and the used in terms of their loading mode (axial, bearing alloys, non-ferrous mate- ment methods require more and dynamic properties), but also GKN Powder Metallurgy’s own process parameters [2]. plane bending, beam, rolling contact rials and PM grades used in Metal more model parameters. Those temperature-dependent properties, fatigue testing capacity has, there- The most developed database for and torsional fatigue) as a function Injection Moulding (MIM). model parameters have a few special such as the creep strength. fore, been organised in such a way as PM materials, the Global Powder of sintered density r. Further fatigue The fatigue data reported in the characteristics: It is not only mechanical proper- to create datasets in accordance with Metallurgy Database (GPMD) was design relevant material properties GPMD represent the results of • They are often based on two or ties that are listed, but chemical current fatigue assessment methods. achieved under the guidance of Dr or model parameters (mean stress fatigue testing programmes from more independently measured compositions, material costs, The number of relevant material David Whittaker, the global project sensitivities M, fatigue notch factors a wide range of sources globally, values (closed component, error

substance risk and eco-impact are properties and model parameters is leader appointed by the European Kf or material scatter ss) were not and represents a range of figures propagation law) – for example

also included. Depending on the too high for an individual identifica- Powder Metallurgy Association communicated. As a result, the most for performance under certain the fatigue notch factor Kf is the material of interest, there may be tion (density dependency). Therefore, (EPMA), and Howard I Sanderow, accurate fatigue assessment possible test conditions, taking the form of ratio of two measured fatigue

more properties available, such as a well-balanced methodology (good on behalf ofthe Metal Powder is based on the fully reversed (axial) statistical ranges and not guaranteed strengths at the knee point sA electrical and thermal conductivity or simplifications, valid similarities Industries Federation (MPIF), fatigue strength at the knee point sA minimum properties. values (unnotched and notched).

The final change – if no other information sources are available – to generate a dataset for a fatigue assessment is via synthetic values ( = 1) (1 ) the High Cycle Fatigue(synthetic (HCF) Wöhlerdomain lines. As sa-N). result, An finite fatigue lives N ( ) = 1 | 2| alternative to real measured mate- 𝐴𝐴𝐴𝐴 2 cannot be predicted. 𝐴𝐴𝐴𝐴 𝜎𝜎𝜎𝜎 𝑅𝑅𝑅𝑅 − − 𝑅𝑅𝑅𝑅 rial properties are meta-models, 𝜎𝜎𝜎𝜎 𝑅𝑅𝑅𝑅 � √ − 𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 for example, regression models, Only one reference point, the fully reversed (tension-compression or The final change – if no other information sources are available – to which correlate more complex bending) fatigue strength at the knee point σA(R=-1)), is needed for the generate a dataset for a fatigue assessment is via synthetic values material properties, such as fatigue construction of the Haigh damage line. The curve progression is (synthetic Wöhler linesstrength σ-N). Anat the alternative knee point to values real measured material independent of any static material property. The pulsating (tension- compression or bending) fatigue strength at the knee point σA(R=0) is properties are meta-modelsA, withs, easierfor example to derive, regressionmaterial models, which correlate more complexproperties material such properties as hardness, such H or as fatigue strength at the therefore:

knee point values σA, ultimatewith easier tensile to strengthderive material su. Those properties such as approaches are very σold, but still in ( = 1) hardness H or ultimate tensile strength u. Those approaches are very old, ( = 0) = use [5]: 2 2 but still in use [11]: 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 − 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 �

A new class of mean stress σm correction models incorporate the loading , ( = 1) = , × ∗ ratio R in an explicit manner as proposed by Jasper, Walker and Smith- 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡 𝑅𝑅𝑅𝑅 − 𝑓𝑓𝑓𝑓𝑅𝑅𝑅𝑅푅푅푅 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎𝑢𝑢𝑢𝑢 Watson-Topper [15]. The Smith-Watson-Topper damage parameter PSWT In this equation the followingIn this equationabbreviations the following are used: can also be applied to purely linear-elastic material behaviour (Hooke’s abbreviations are used: law). In this case:

σA,tc(R=-1): Fully reversedsA,tc(R=-1): tension Fully-compression reversed fatigue strength at the knee point tension-compression fatigue = × × = . Fig. 3 A bearing cap produced by GKN Sinter Metals strength at the knee point Fig. 4 A selection of VVT rotors and stators produced by GKN Sinter Metals 𝑃𝑃𝑃𝑃𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 �𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 𝜀𝜀𝜀𝜀𝐴𝐴𝐴𝐴 𝐸𝐸𝐸𝐸 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 = ( + ) × = . fR=-1, s: Material type dependent ( = 1) (1 ) constant in the range between ( ) = 𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 𝑚𝑚𝑚𝑚 𝐴𝐴𝐴𝐴 𝐴𝐴𝐴𝐴 1 | 2| 𝑃𝑃𝑃𝑃 � 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝐴𝐴𝐴𝐴 2 fR=-1, s=0.3 (for aluminium alloys) 𝐴𝐴𝐴𝐴 𝜎𝜎𝜎𝜎 𝑅𝑅𝑅𝑅 − − 𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎 𝑅𝑅𝑅𝑅 � . • They are often the result of a The Haigh damage line of the corre- to f =0.45 (for steels) All these models can be varied independent√ of any −static𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 material strength at the knee1 point sA(R=-1) R=-1, s Only one reference point, the fully reversed (tension-compression or ( ) = regression analysis (data fitting). sponding mean stress diagram can by using parameters from the true property. The pulsating (tension- and its corresponding2 mean0 5 stress s *: Modified ultimate tensile bending) fatigue strength at the knee point σA(R=-1)), is needed for the u 𝐴𝐴𝐴𝐴 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 − 𝑅𝑅𝑅𝑅 Prominent examples are the only be constructed according to stress-strain curve and/orconstruction from of the Haighcompression damage line. orThe bending) curve progression fatigue is sm𝜎𝜎𝜎𝜎=0,𝑅𝑅𝑅𝑅 the Haigh𝜎𝜎𝜎𝜎 � damage� line can be strength independent of any static material property.( = The1) pulsating(1 ) (tension- Wöhler line s-N parameters; the earliest models from Goodman the cyclic stress-strain curve. A strength at the kneeWith point the referencesA(R=0) point constructed.of the fully reversed The Walker (tension equation-compression is or ( ) = σ compression or bending) fatigue strength 2at the knee1 point| 2 | A(R=0) is for example, the cut-off point NK (linear sA-su fit), Gerber (parabolic According to FKM (Forschungs- good overview of different analytical is therefore:𝐴𝐴𝐴𝐴 bending) fatigue strengtha atlittle the more knee flexiblepoint σA (R=due- 1)to anda further its corresponding therefore: 𝐴𝐴𝐴𝐴 𝜎𝜎𝜎𝜎 𝑅𝑅𝑅𝑅 − − 𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎 𝑅𝑅𝑅𝑅 � σ and the slope k. sA-su fit) and Soderberg (linears A-sy kuratorium Maschinenbau) guide- proposals for Haigh damage lines for √ mean stress− 𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 m=0, the Haighfree parameter. damage line The can square-root be constructed . The Walker Only one reference point, the fully reversedequation (tension is- acompression little more or flexible due to a further free parameter. The • They do not always have a clear fit). The mean stress sensitivity M lines, su* is not the pure material unnotched and notched components ( = 1) dependency of the Smith-Watson- bending) fatigue strength( at= the0) = knee point σA(R= -1)), is needed for the (slope of the Haigh damage line) of property. It is more a synthesised can be found in [10]. Case studies square2 2 -root dependencyTopper of the Smithmodel-Watson is replaced-Topper by the model free is replaced by physical meaning: this is the construction of the Haigh damage line.𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 The− curve progression is 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 � γ case for the Palmgren-Miner sintered PM steels is higher than its value, which was defined for a of combined notch and meanindependent stress of any static material property.the freeThe pulsatingparameter (tension as:- parameter g as: A new class of mean stress σm correction models incorporate the loading counterpart from fully dense wrought survival probability of P =97.5%. effects on the Haigh damagecompression line are or bending)A new fatigue class strength of mean at the stress knee points σA(R=0) is linear damage accumulation s ratio R in an explicit manner as proposed by Jasper, Walker andm Smith- steels having the same ultimate Moreover, it was corrected to incor- discussed in [7]. However,therefore: discus- correction models incorporate 1 rule of D=1. In this formulation, Watson-Topper [15]. The Smith-Watson-Topper damage parameter PSWT ( ) = can also be applied to purely linear-elastic material behaviour (Hooke’s 2 𝛾𝛾𝛾𝛾 tensile strength su. Therefore, this porate the effect of a potential mate- sions of whether Kt should be applied the loading ratio R in an explicit it is only a counting variable law). In this case: − 𝑅𝑅𝑅𝑅 parameter has a significant impact rial anisotropy and a potential size on s and K on s are no longer manner as proposed ( by= Jasper,1) 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 � � without having a microstructural m f A ( = 0) = The weakness2 2 of the equationsThe weakness above are of the the progression equations of the Haigh link to a real fatigue damage on the accuracy of the fatigue effect. However, these details should useful, since that behaviour will Walker= and ×Smith-Watson-Topper× 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴=𝑅𝑅𝑅𝑅 −. 𝐴𝐴𝐴𝐴 � damage line for compressive mean stresses σm and its limited mean stress assessment method. not unnecessarily complicate this affect the slope (mean stress sensi- [9]. The𝜎𝜎𝜎𝜎 𝑅𝑅𝑅𝑅Smith-Watson-Topper above are the progression of the mechanism (for example micro- 𝑃𝑃𝑃𝑃𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 �𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 𝜀𝜀𝜀𝜀𝐴𝐴𝐴𝐴 𝐸𝐸𝐸𝐸 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 0.5 A new class of mean stress= ( σm +correction) × sensitivity= models. incorporate of M2=(2) the- 1=loadingHaigh0.41 (the damage negative line signfor compressive is neglected at this crack formation and propaga- The most significant drawback of simple correlation approach. Similar tivity M) of the Haigh damage line. damage parameter PSWT can also ratio R in an explicit manner as proposedposition) by Jasper,. This Walker value and is Smith, formean most- stresses higher strengths and its sintered limited PM steels (heat the GPMD is related to the hidden recommendations can be found in [6, Newer analytical approaches remove be𝑃𝑃𝑃𝑃𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 applied� 𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚 to𝜎𝜎𝜎𝜎 𝐴𝐴𝐴𝐴purely𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 linear-elastic𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 m tion). Watson-Topper [15]. The Smith-Watson-Topper damage parameter PSWT treated), too optimistic. Currentlymean stress, the sensitivitybest analytical of M Haigh=(2)0.5- damage line for low notch sensitivity of sintered PM 7, 8]. The corresponding mean stress the static property dependency,can also for be appliedmaterial to purely behaviourlinear-elastic1 (Hooke’s material. behaviour law). (Hooke’s 2 • Sometimes, they are based on ( ) = sintered PM steels was developed by Keusemann (sigmoidal σA-σm fit) [17]. steels, though a reference library of sensitivities M , M , M and M are example as shown for thelaw). Jasper In this case: In this case: 2 0 5 1=0.41 (the negative sign is neglected 1 2 3 4 − 𝑅𝑅𝑅𝑅 a special probability density 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 � � at this position). This value is, for s-N curves attached to the database also defined. equation [9]: With the reference point of the fully reversed (tension-compression or distribution. Variations from = × The× parameters= . are designatedmost higher as: strength sintered PM goes some way to addressing this Alternatively, there are dozens of bending) fatigue strength at the knee point σ A(R=-1) and its corresponding the ad-hoc assumed Gaussian ( ) ( ) = 1 1 mean stress σm=0, the Haigh𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 damage𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 line can𝐴𝐴𝐴𝐴 be constructed. The Walker steels (heat treated), too optimistic. question for Fe-Cu-C materials analytical proposals for the Haigh ( ) = 𝑃𝑃𝑃𝑃 �𝜎𝜎𝜎𝜎 𝜀𝜀𝜀𝜀 𝐸𝐸𝐸𝐸 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 normal distribution will generate 2 1 | 2equation| is a little more flexible= due( to a+ further) × free =parameter. . The [4]. This phenomenon is a clear damage line. The earliest models are 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 − − 𝑅𝑅𝑅𝑅 Currently, the best analytical Haigh 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 � square -root dependency of the Smith-Watson-Topper model is replaced by a higher mathematical effort to − 𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 𝑚𝑚𝑚𝑚 𝐴𝐴𝐴𝐴 𝐴𝐴𝐴𝐴 damage line for sintered PM steels advantage of that material group those from Goodman (linear s -s √ γ 𝑃𝑃𝑃𝑃 � 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 extract the relevant statistical A u Only one reference point, the fully reversed (tension-thecompression free parameter or as: . was developed by Keusemann which cannot be extracted in an fit), Gerber (parabolics A-su fit) and bending) fatigue strengthOnly at theone knee reference point σA(R= point,-1)), is theneeded fully for the 1 moments. ( ) = 1 construction of the Haigh damage line. The curve progression is 0 5 (sigmoidal sA-sm fit) [11]. easy way from the datasets of the Soderberg (linear sA-sy fit). More reversed (tension-compression or ( ) = 2 independent of any static material property. The pulsating (tension- 2 −𝛾𝛾𝛾𝛾 𝑅𝑅𝑅𝑅 𝐴𝐴𝐴𝐴 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚− 𝑅𝑅𝑅𝑅 The parameters are designated as: According to these arguments, it GPMD. Finally, there is no informa- complicated analytical proposals, for bending) fatigue strength at the knee 𝐴𝐴𝐴𝐴 𝜎𝜎𝜎𝜎 𝑅𝑅𝑅𝑅 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝜎𝜎𝜎𝜎 � � compression or bending) fatigue strength at the knee point σA(R=0) is 𝜎𝜎𝜎𝜎 𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎 � � TheWith weakness the reference of the equationspoint of the above fully are reversed the progression (tension of-compression the Haigh or appears that only a very basic fatigue tion regarding the High Cycle Fatigue example from Launhardt-Weyrauch therefore: point sA(R=-1), is needed for the With the reference point of sA(R=-1): Fully reversed (tension- bending) fatigue strength at the knee point σA(R=-1) and its corresponding damage line for compressive mean stresses σm and its limited mean stress assessment is possible based on (HCF) domain. As a result, finite [9], Stüssi [10], Oding [10] or Smith construction of the Haigh damage 0.5the fully reversed (tension- compression or bending) fatigue sensitivitymean stress of M 2σ=m(2)=0, -the1=0.4 Haigh1 (the damage negative linesign can is neglected be constructed at this . The Walker ( = 1) the fatigue properties of the GPMD. fatigue lives N cannot be predicted. [8], are rarely used in practice. line. The( = curve0) = progression position)equation is . This is a value little moreiscompression, for mostflexible higher due orstrength to bending) a further sintered free fatigue PM parameter steels (heat. The strength at the knee point 2 2 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 − treated)square,- tooroot optimistic. dependency Currently of the, the Smith best- analyticalWatson- TopperHaigh damage model lineis replaced for by 𝐴𝐴𝐴𝐴 � 𝜎𝜎𝜎𝜎 𝑅𝑅𝑅𝑅 sinteredthe free PM parameter steels was γ as:developed by Keusemann (sigmoidal σA-σm fit) [17]. σ A new class of mean stress m correction models incorporate the loading ratio R in an explicit manner as proposed by Jasper, TheWalker parameters and Smith are- designated as: 60 Powder Metallurgy Review Spring 2021 © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd 1 Spring 2021 Powder Metallurgy Review 61 Watson-Topper [15]. The Smith-Watson-Topper damage parameter PSWT ( ) = 2 𝛾𝛾𝛾𝛾 can also be applied to purely linear-elastic material behaviour (Hooke’s − 𝑅𝑅𝑅𝑅 law). In this case: 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 � � The weakness of the equations above are the progression of the Haigh = × × = damage. line for compressive mean stresses σm and its limited mean stress 0.5 sensitivity of M2=(2) -1=0.41 (the negative sign is neglected at this 𝑃𝑃𝑃𝑃𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 �𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 𝜀𝜀𝜀𝜀𝐴𝐴𝐴𝐴 𝐸𝐸𝐸𝐸 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 = ( + ) × = position). . This value is, for most higher strength sintered PM steels (heat treated), too optimistic. Currently, the best analytical Haigh damage line for 𝑃𝑃𝑃𝑃𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 � 𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 sintered PM steels was developed by Keusemann (sigmoidal σA-σm fit) [17]. 1 . ( ) = 2 0 5 The parameters are designated as: − 𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 � � With the reference point of the fully reversed (tension-compression or

bending) fatigue strength at the knee point σA(R=-1) and its corresponding

mean stress σm=0, the Haigh damage line can be constructed. The Walker equation is a little more flexible due to a further free parameter. The square-root dependency of the Smith-Watson-Topper model is replaced by the free parameter γ as:

1 ( ) = 2 𝛾𝛾𝛾𝛾 − 𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 � � The weakness of the equations above are the progression of the Haigh

damage line for compressive mean stresses σm and its limited mean stress 0.5 sensitivity of M2=(2) -1=0.41 (the negative sign is neglected at this position). This value is, for most higher strength sintered PM steels (heat treated), too optimistic. Currently, the best analytical Haigh damage line for

sintered PM steels was developed by Keusemann (sigmoidal σA-σm fit) [17].

The parameters are designated as:

( + 120) 1 stress-based fatigue assessment Added carbon content C (graphite recognition that more fatigue testing ( ) = , 2 𝛼𝛼𝛼𝛼 methods. Both methods have their addition) will also vary. Due to the experiments had to be done under 𝑋𝑋𝑋𝑋 12𝐻𝐻𝐻𝐻 −𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 𝑅𝑅𝑅𝑅 � � strengths and applications, meaning focus on higher strength materials, higher loading ratios R. This was one =0.226√𝐴𝐴𝐴𝐴+𝑅𝑅𝑅𝑅𝐸𝐸𝐸𝐸𝐴𝐴𝐴𝐴× 10 this conflict cannot be solved at this the carbon content C (graphite of the reasons to retire the rotating −4 position, because it incorporates addition) commonly varies between bending fatigue testing machine: its 𝛼𝛼𝛼𝛼 𝐻𝐻𝐻𝐻 The similarity to the JasperThe similarity, to the Walker to the and Jasper, to the to Smith the -Watson-Topper some cultural elements. Fig. 5 gives C=0.5% C to C=0.8% C (eutectoid fixed and non-variable loading ratio equations, in regardWalker of the mean and to stress the Smith-Watson- σm correction, is apparent. In these an overview of Germany’s ‘fatigue composition, 100% pearlite). of R=-1, in favour of newer and faster equations, the parametersTopper are equations, coded as in follows regard [18 of]: schools’. However, experience has shown that flat bending fatigue testing machines.

the mean stress sm correction, is A sufficient number of component even this parameter will provoke Axial fatigue testing machines are apparent. In these equations, the Wöhler lines s-N, together with huge discussions, since the added not considered here. The result was parameters are coded as follows [12]: numerical fatigue life N predictions, carbon content C is determined in a shifted composition of generated could answer the question for the a plant-specific manner. Very small Wöhler lines s-N (for the investigation sA,b(R=-1): Fully reversed bending fatigue strength at the knee point better fatigue assessment method for carburisation or decarburisation of the materials, not for component sintered PM steels. effects from the plant-specific Wöhler lines s-N) from approx. 75% X: Model-inherent factor (surface sintering furnaces and/or sintering at R=-1 and 25% at R=0 (approx. year defect: X=1.43, internal defect: atmospheres are compensated by 2000) to approx. 50% at R=-1, 25% at X=1.56) Requirements and hurdles an adjustment of the added carbon R=0 and 25% at R=0.5 (approx. year H: Vickers hardness content C (graphite addition). Another 2020). AREA: Projected defect area in There have been several attempts interaction can be defined in terms of Charpy or Izod toughness tests the first principals 1 direction to establish a systematic in-house the dimensional stability (shrinkage were an essential procedure to R: Loading ratio Powder Metallurgy fatigue database or growth). Since the dimensional characterise sintered PM steels and a: Mean stress exponent at GKN in the past. Those attempts stability has a higher importance, to derive qualitative conclusions were unsuccessful for different the added carbon content C (graphite regarding their application spectrum reasons and faced differing hurdles. addition) can be used for smaller (temperature J, strain-rate De/Dt or Modern fatigue At this point, it is worth reviewing corrections. environment), but these values did assessment methods the main hurdles and failures on this not find a way into a general strength journey. Focus conflicts assessment due to their qualitative Most customers of the German- Another stumbling block for the nature. Therefore, the existing tough- speaking PM industry have a strong Prioritisation conflicts establishment of a systematic ness datasets were not introduced background in fatigue design. First of all, the relevant powder in-house database was a focus on into the database because there is no Fig. 5 Fatigue design landscape of Germany – a personal selection based on Moreover, they are familiar with a compositions which need to be less important parameters and the use for them, neither for the cyclic read papers, articles and books. The list does not claim to be comprehensive. wide range of fatigue assessment characterised have to be chosen. This usage of Wöhler lines s-N for A to B strength assessment nor for the static Because of its strong position in the automotive and industrial machinery methods, particularly the methods process requires a discussion with comparisons. The usage of Wöhler strength assessment. For the latest industry, Germany has produced a significant number of fatigue researchers. described in the FKM guidelines all plants if the organisation operates lines s-N for A to B comparisons case, the ductility is expressed over A few ‘fatigue schools’, notably in Darmstadt/Frankfurt (Fraunhofer LBF), and Germany’s technical standards at a number of different locations. cannot be recommended due to the the fracture strain ef or the reduced München/Ottobrunn (Industrieanlagen-Betriebsgesellschaft mbH, IABG) and TGL 19350, 19333, 19340 and DIN Since most PM plants have a specific high time and testing effort. However, cross section Z. Dresden/Freiberg (IMA Material Research and Application Technology GmbH) 743. The TGL standards (Technische product focus, the powder composi- the effects of different graphite types, have their origin in the lightweight design work for the aerospace industry. This Normen, Gütevorschriften und tions most commonly used at each iron powder suppliers or sintering Importance conflicts historical background is the motivation to apply state-of-the-art fatigue design Lieferbedingungen) were the will vary. A ranking and a weighting furnaces were investigated in that It is vital to scrutinise the importance approaches on sintered PM components. The two larger dots mark the centres standards of the former German of material importance is therefore manner. Certainly, the sintering of the fatigue testing, material of fatigue design of sintered PM components (RWTH Aachen and Fraunhofer Democratic Republic (GDR). Due to needed. furnace and its settings have an influ- characterisation and strength LBF, Darmstadt/Frankfurt). The four smaller dots mark institutes and universi- their limited raw material supply, Good practice is to start with the ence, meaning good practice is to assessment of PM components. ties which had a considerable contact with sintered PM components resource-conserving economical most often used powder composition. choose a sintering furnace type with It is often overlooked that these activities were mandated by the A Pareto-like distribution can be settings and a sintering atmosphere activities make a major contribution government. This resulted in a established (e.g. 80% of all produced typically used for the components, to a component’s reliability and R: Loading ratio g: Walker exponent leading position in terms of fatigue components may be made from 20% which should be strength-assessed the general quality capability of s (R=0): Pulsating (tension- A An alternative to the correlation with design, tolerance design, technical of a specific powder composition). afterwards. The investigation of a company. The creation and the compression or bending) fatigue the ultimate tensile strength su is the reliability and other engineering According to this principle, the first the less important parameters maintenance of a systematic in-house strength at the knee point Murakami approach. This approach disciplines. Different to their West dataset should be an iron/copper/ mentioned above hindered the database is a clear differentiator over PSWT: Smith-Watson-Topper uses the easiest to measure material German counterparts (DIN stand- carbon alloy, due to its wide applica- systematic fatigue testing of the more competitors in terms of recognised damage (mean stress sm) property, the hardness H, as [12]: ards), the TGL standards were legal tion. Afterwards, less widely used relevant variants for a long time. expertise and speed during the parameter in character. powder compositions can be tested if Analytical, numerical and experi- material, process and design ( + 120) smax: Maximum stress (sm+sA) The importance of this field can the customer requires those data for mental (strain gauge) investigations definition phases when working with a , ( = 1) = be visualised over a web of institutes a new product, or for extraordinarily of typical stress states have shown new customer or application. sm: Mean stress 𝑋𝑋𝑋𝑋 12𝐻𝐻𝐻𝐻 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 𝑅𝑅𝑅𝑅 − and universities across Germany. In highly-loaded components that that most sintered PM components Who else other than the PM s : Endurable stress amplitude √𝐴𝐴𝐴𝐴𝑅𝑅𝑅𝑅𝐸𝐸𝐸𝐸𝐴𝐴𝐴𝐴 A Consequently, a hardness H contrast to the strain-based fatigue cannot be manufactured without are loaded under pulsating loading community is responsible for e : Endurable strain amplitude A dependent mean stress sm correction assessment methods that dominate a previously performed strength conditions (loading ratio R=0) or at generating this knowledge? It is solely E: Young’s modulus term was also developed: in North America, Europeans favour ( + 120) 1 assessment. even higher R values. This led to the a requirement of the PM community ( ) = , 2 𝛼𝛼𝛼𝛼 𝑋𝑋𝑋𝑋 12𝐻𝐻𝐻𝐻 −𝑅𝑅𝑅𝑅 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 𝑅𝑅𝑅𝑅 � � =0.226√𝐴𝐴𝐴𝐴+𝑅𝑅𝑅𝑅𝐸𝐸𝐸𝐸𝐴𝐴𝐴𝐴× 10 62 Powder Metallurgy Review Spring 2021 © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd Spring 2021 Powder Metallurgy Review 63 −4 The similarity to the Jasper,𝛼𝛼𝛼𝛼 to the Walker𝐻𝐻𝐻𝐻 and to the Smith-Watson-Topper

to generate this data, to work with the Balshin power-law. If the curve The same holds true with the parti- (plausibility checking, data fitting, the data and to share the data with fitting procedure according to this tioning of the Wöhler lines s-N into model parameter derivation etc) and customers. It would be fatal if we power-law is accepted, the potential the HCF domain (failure of all speci- the final database setup. All relevant should leave this task to external discrepancy between the green mens on the chosen stress horizon) production information (powder

companies, institutes or, in the worst (compacted) density rgreen and the and the LLF (Long Life Fatigue) lot, compaction press, compaction case, to the customers. In this latter final sintered densityr no longer domain (staircase-like failure and method, sintering furnace, sintering case, customers could stipulate plays a role because any required survival of the specimens on the same program, including sintering atmos- every detail and look for the cheapest sintered density r can be inter- or chosen stress horizon). It is believed phere, cooling rate DJ/Dt, belt speed producer. Most PM component extrapolated. that the fatigue strength at the knee v, sintering temperature J, dew point

designs come from the customers point sA (endurance limit) is of higher Tdew and the sintering profileJ [t]) and and the assembly of the components Timing conflicts importance than the transient fatigue quality-related information should be to sub-systems and the system Fatigue testing is time consuming life domain. According to that claim, it documented as much as is possible. integration is done elsewhere. This and further data preparation (plau- is consequent to renounce the speci- The loading of the fatigue testing means the main expertise of the sibility checking, data fitting, model mens from the HCF domain in the machines is often done by students PM community is related to powder parameter derivation, etc) also needs hope of saving a significant amount of with a limited contract, allowing handling, the whole PM process time. In the early fatigue testing fatigue testing time. This is a fallacy, for a possible project transfer from chain, the material and the resulting definition phase, it is quite common because the fatigue lives N of sintered student to student. In this case, it is material properties. Consequently, to underestimate the high time and PM steels in the HCF domain are very of critical importance to guarantee a the fatigue testing activities need the testing effort needed. The attempt to short. As a consequence, the fatigue smooth transition without any loss of protecting hand of the management derive a fully factorial fatigue testing testing time savings are lower than knowledge. Fig. 6 Fatigue testing machine park with identical RUMUL resonance flat and the quality departments at PM matrix with all possible material- expected. bending fatigue testing machines to guarantee a consistent testing procedure companies. density-heat treatment (secondary Another drawback is due to the Consistency conflicts operations) combinations is unfea- impossibility of estimating the cut-off The fatigue testing machine parks of

Processing conflicts sible and not very useful, because point NK and slope k of the Wöhler line many institutes and PM companies The tested sintered density r is of many possible combinations are s-N. These parameters are of critical are the result of the CAPEX situation mation. Moreover, the loading ratio commonly used in the tensile mean

critical importance. Over many years, irrelevant. interest for damage accumulation of the past years and the focus, be it R can be varied across a very wide stress sm domain (R >-1). The testing it was very common to test just one A careful scheduling of manpower calculations and the assessment of on materials or components, of an range, from compressive to tensile frequency f is much higher and

‘typical’ density variant. Since the and fatigue testing machine capacity variable load spectra. The piecewise institute. A common dilemma is the mean stresses sm. Disadvantages depends on the specimens’ mass m final sintered densityr was a priori is needed. Even if fatigue testing production (different lots, equipment decision between whether testing are the higher operation costs due and axial stiffness EA. These fatigue and time periods) of specimens to procedures should be universal or to the energy consumption of the testing machines are run in a stress- fill open gaps or to derive previously specific. A consistent fatigue testing hydraulic aggregates and the lower controlled manner with relatively low “It would be fatal if we should leave unconsidered material properties or procedure is essential for a correct fatigue testing frequency f to mini- loads F(t), meaning the stress-strain model parameters cannot be recom- estimation of the density dependency mise the thermal loading due to the s-e relation corresponds to Hooke’s

this task to external companies, mended for a systematic in-house P(r), the mean stress sensitivity M, high realised plastic strain ep and to law and the recording of the strain database approach due to slightly the fatigue notch factor K or the realise the required strain amplitude response e can be neglected. Rotating institutes or, in the worst case, to f different production conditions, which material scatter ss. Superimposed ea without overshooting. bending fatigue testing machines the customers.” might interfere with systematic trends. machine effects could disguise A general problem of axial fatigue exhibit a fixed and non-variable Therefore, the largest fatigue testing or falsify valuable findings; this is testing machines is their sensitivity loading ratio of R=-1. Moreover, a time saving relates to the right choice the case if different fatigue testing against superimposed bending complex machining operation is unknown, the density variant was machines can run twenty-four hours of material to be tested (relevance) machines are used to generate a moments. Imperfect shaped fatigue needed to generate the required characterised through the green a day, seven days a week and fifty-two and its consequent execution (focus). common dataset. Using similar testing specimens (this is the case circular fatigue testing specimen.

(compacted) density rgreen. Depending weeks a year, the machines must be The reduction of the number of fatigue fatigue testing machines of the same if sintered, rather than machined, Consequently, larger preforms (and on the material and sintering (wax fed with new specimens in a regular specimens to a minimum is not the type guarantees comparable results PM specimens are tested with their therefore more material/powder) are removal, shrinkage or growth and manner and they must be maintained correct approach, because experience in terms of the load control (stress- or as-sintered surface), gripping distor- needed to compensate the material resulting microstructure), there is a and calibrated to guarantee a reli- has shown that the editorial revision of strain-controlled fatigue testing), tions or not perfectly aligned fatigue loss from the machining. In addition,

certain discrepancy. This discrepancy able performance, meaning effective existing datasets (in the case of identi- loading mode (stress distribution, testing machine axis will affect the residual stress sR measurements are hinders a simple A to B comparison fatigue testing time is reduced. fied contradictions and falsifications) axial, bending or torsional loading), relative stress gradient c* free axial needed to investigate the resulting between different materials if the The scattering around the found from an existing database is more or frequency f and signal waveform F(t) loading condition. However, further surface condition. Flat bending property-density P(r) relation is not mean values is also of interest less impossible. (sine, triangle etc). Servohydraulic or machining operations (turning and fatigue testing machines can be run known. because modern fatigue life predic- resonance fatigue testing machines grinding) or strain gauge assisted with unmachined rectangular fatigue However, one density variant is tions incorporate this effect through Communication conflicts have different applications. axis adjustments are time consuming specimens. The as-sintered surface

nowhere near enough, because PM safety factors js. This is due the fact Larger fatigue testing programmes Strain-controlled Low Cycle Fatigue and therefore not desired. condition is beneficial, because most plants offer a wide range of sintered that material properties and derived run over a longer time period and (LCF) fatigue experiments require an Resonance axial fatigue testing sintered PM components are sold with densities r. Therefore, more than model parameters have a statistical many different people are involved, exact controlling of the axial exten- machines are sensitive to ‘zero their original surface. two density variants are needed to (random) character. Therefore, the starting from the powder blending, someter strain Dl, the simultaneous crossings’, for example in the case The flat bending fatigue testing approximate a curve fitting with a fatigue testing program should not be specimen compaction, sintering and recording of strain e and stress s and of fully reversed fatigue tests at a machines are fast and robust in higher polynomial degree. Three reduced in this way to accelerate the heat treatment, to quality control, a larger machine displacement to loading ratio of R=-1. Therefore, terms of potential misalignments. density levels are sufficient to apply general processing. fatigue testing, data preparation generate the required plastic defor- these fatigue testing machines are Further, the calibration and the main-

64 Powder Metallurgy Review Spring 2021 © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd Spring 2021 Powder Metallurgy Review 65 These fatigue testing machines are run in a stress-controlled manner with relatively low loads F(t), meaning the stress-strain σ-ε relation corresponds to Hooke’s law and the recording of the strain response ε can be neglected. Rotating bending fatigue testing machines exhibit a fixed and non-variable loading ratio of R=-1. Moreover, a complex machining operation is needed to generate the required circular fatigue testing specimen. Consequently, larger preforms (and therefore more material/powder) are needed to compensate the material loss from the machining.

Moreover, residual stress σR measurements are needed to investigate the resulting surface condition. Flat bending fatigue testing machines can be run with unmachined rectangular fatigue specimens. The as-sintered surface condition is beneficial, because most sintered PM components are sold with their original surface.

The flat bending fatigue testing machines are fast and robust in terms of potential misalignments. Moreover, the calibration and the maintenance effort are lower. As a result, malfunctions of a flat bending fatigue testing machine will be covered earlier. In our case, five similar resonance flat bending fatigue testing machines of the type “RUMUL”, as shown in Fig. 2, guarantee a consistent testing procedure.

Team All the conflicts mentioned above can be avoided by using a proper fatigue team structure, as shown in Fig. 3, with an expert from the Simulation (FEA), Fatigue, Testing, Material and Process departments. Potential harmonisation demands could be related to the required output variables (stresses σ and strains ε), to the correct approximation of the boundary conditions, to the material approximation (elastic or elastic/plastic material) or regarding the incorporation of process specific effects (implementation of

residual stresses σR). Agreement between the numerical and the experimental setup should be as close as possible.

FIG 3

Managing PM fatigue data | contents | news | advertisers | events | website | e-newsletter | | contents | news | advertisers | events | website | e-newsletter | Managing PM fatigue data Good simplifications, valid similarities and exact derivations stress hypothesis to convert a σ1 Prefix Remarks Suffix Remarks In-house testingτ efforts can be reducedmultiaxial stress through state existinginto an knowledge. An Produced by die Austenitised, quenched in oil or equivalent uniaxial stress state. Press and Austenitised, quenched example is the required investigation of the equivalent stress hypothesis to PS compaction and QT water, tempered at J=180°C for The a priori assumed knowledge Sinter and tempered convert a multiaxial stress stateof into the materialan equivalent behaviour uniaxialwill stress state. The sintering t=1 h a priori assumed knowledge of savethe fatiguematerial experiments behaviour with will save fatigue Produced by different loading modes. A common Binder Jetting Austenitised during the sintering, experiments with different loading modes. A common recommendation for Binder Austenitised, rapid cooled recommendation for porous BJ with subsequent RCT quenched in gas, tempered at porous sintered PM steels is: Jetting and tempered sintered PM steels is: sintering (AM J=180°C for t=1 h process) = Carburised to approx. C=0.8% Laser Produced by laser Carburised, austenitised, C in salt, gas or vacuum, 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 1 Beam beam Powder quenched and tempered The𝜎𝜎𝜎𝜎 easiest𝜎𝜎𝜎𝜎 way to prove an L-PBF CHT austenitised, quenched in oil, Powder Bed Fusion (AM (case hardened and τ equivalent stress hypothesis for water or gas, tempered at Bed Fusion process) tempered) σ1 proportional loadings (multiaxial J=180°C for t=1 h stress state is the result from Fig. 7 Internal peak stress speak around a pore caused by a normal stress (left) Carburized to approx. C=0.8% a single loading F(t), all stress Produced and a shear stress (right), adopted from [13] Carburised, austenitised, C in salt, gas or vacuum with components are aligned and have Metal by injection quenched and tempered nitrogen-rich compounds, the same time history [phase MIM Injection moulding, CNT (carbonitrided and austenitised, quenched in oil, τ angle]) is to compare the bending Moulding debinding and tempered) water or gas, tempered at and the torsional fatigue testing sintering J=180°C for t=1 h τmax results [13]. Both loading modes Produced by die exhibit a non-homogeneous stress Austenitised via induction, compaction and Austenitised via induction, distribution with a certain relative Powder quenched and tempered PF sintering with a IHT quenched in oil or water, stress gradient c*. This is the Forge (induction hardened and The easiestreason way why to theprove bending an equivalent fatigue stress hypothesis for proportional subsequent die tempered at J=180°C for t=1 h loadings (multiaxial stress state is the result from a single loading F(t), all tempered) The easiest σway1 to prove an equivalent stress hypothesis for proportional forging operation σ stressstrength components at the are kneealigned point and have sA,b the same time history (phase loadings (multiaxial stress state is the resultT hefrom easiest a single way loading to pro veF(t), an all equivalent stress hypothesis for proportional σ2 σ2 σ1 angle))is usedis to compare instead the of bending the tension- and the torsional fatigue testing results Nitrided in salt or vacuum stress components are aligned and have theloadings same time(multiaxial history stress (phase state is the result from a single loading F(t), all N Nitrided The easiest way to prove an equivalent[19 stress]. Both hypothesis loading mode for proportionals exhibit a non -homogeneous stress distribution angle)) is to compare the bending and the torsionalstresscompression components fatigue testing fatigue are alignedresults strength and have at the same time history (phase (plasma nitriding) [19loadings]. Both loading (multiaxial mode stresss exhibit state a nonis the-homogeneousT withresulthe easiesta certainfrom away singlerelativestress to pro loadingdistribution stressve an F(t),gradientequivalent all χ* .stress This is hypothesis the reason for why proportional the bending angle))knee is point to compare sA,tc. Thethe bending difference and theis torsional fatigue testing results Nitrocarburised in salt stress components are aligned and haveloadingsfatigue the strengthsame (multiaxial time at historythe stress knee (phasestate point is σtheA,b isresult used from instead a single of the loading tension F(t),- all withThe a easiestcertain relativeway to prostressveThe an gradient easiest equivalent wayχ*. T stresstoh[19is pro theis]. Bothve thehypothesis stress an reason loading equivalent state why for mode proportional the (bending:stresss bendingexhibit hypothesis a 1D non stress-homogeneous for proportional stress distribution angle)) is to compare the bending andstress the torsional components fatigue are testing aligned results and have the sameσA,tc time history (phase NC Nitrocarburised or vacuum (plasma fatigueloadings strength (multiaxial at the stress knee pointstate σisA,b the is usedresultcompression instead from a singleoffatigue the tensionloading strength- F(t), at theall knee point . The difference is the loadings (multiaxialwith stressstate, a certain state torsion: relativeis the 2D result stress stress from gradient astate). single χ* . loadingThis is theF(t), reason all why the bending stress[19]. Both components loading mode are aligneds exhibit and a nonhaveangle))stress-homogeneous the state σsameis to (bending:compare time stress history the1D distribution (phasebendingstress state, and thetorsion: torsional 2D stress fatigue state). testing results nitrocarburising) compression fatigue strengthstress at componentsthe knee pointfatigue are A,tcaligned strength. The anddifference at havethe knee the is the samepoint σtimeA,b is history used instead(phase of the tension- χ stressangle))with statea certainis to(bending: compare relative 1D thestressangle)) stress bending gradient state,is to and compare torsion: [ 19the*. ]T. torsionalhBothis 2Dthe is stressloadingthebending fatigue reason state). mode and testing why the s exhibit the torsional results bending a non fatigue -homogeneous testing results stress distribution compression fatigue strength at the knee point σA,tc. The difference is the fatigue strength at the knee point σA,b withis used a certain instead, = relative of, the stresstension gradient - χ*. This is the reason :why the= bending R Rolled [19]. Both loading mode[19s exhibit]. Both aloading non-homogeneousstress mode sstate exhibit (bending: stress a non distribution- homogeneous1D stress state, stress torsion: distribution 2D stress state). compression= fatigue strength at the kneeχfatigue point strength, =2σA,tc. The, at the:difference knee= point is the σA,b is used instead of the: tension= - Fig. 8 Mohr’s circle for the case of similar bendingwith fatiguea certain, strength relative, stresswith at thea gradient certain knee relative *. This stress is𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 the𝑏𝑏𝑏𝑏 gradientreason𝜏𝜏𝜏𝜏𝐴𝐴𝐴𝐴 𝑡𝑡𝑡𝑡 → 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅why χ𝑐𝑐𝑐𝑐*.𝑅𝑅𝑅𝑅 Tthe𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐h𝑅𝑅𝑅𝑅 is 𝑅𝑅𝑅𝑅bending is𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 the𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅 𝑒𝑒𝑒𝑒reason𝑅𝑅𝑅𝑅 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠 𝑅𝑅𝑅𝑅why𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ the𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐 bending𝑐𝑐𝑐𝑐ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝜎𝜎𝜎𝜎 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 𝜎𝜎𝜎𝜎1 Shot peening as strengthening stress state (bending: 1D stress state,compression torsion: 2D stressfatigue state). strength at the knee point σA,tc. The difference is the SP Shot peened fatigue, strength=2 , at the kneefatigue point strength σA,b is at used the 𝐴𝐴𝐴𝐴 kneeinstead𝑏𝑏𝑏𝑏 , = point𝐴𝐴𝐴𝐴= of𝑡𝑡𝑡𝑡3: theσ,A,b =tension is used - instead of the tension - 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 : : 1 = 2 point s and torsion fatigue strength at the knee point𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 t 𝜏𝜏𝜏𝜏 𝐴𝐴𝐴𝐴values𝑡𝑡𝑡𝑡 → 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑐𝑐𝑐𝑐(Rankine𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝜎𝜎𝜎𝜎 ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐,𝑐𝑐𝑐𝑐𝜏𝜏𝜏𝜏ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐→𝑐𝑐𝑐𝑐, 𝑇𝑇𝑇𝑇𝜎𝜎𝜎𝜎𝑠𝑠𝑠𝑠𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅1𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 −𝜎𝜎𝜎𝜎 operation A,b A,t stress stateσ (bending: 1D stress state, torsion: 2D stress state). compression= fatigue3 strengthcompression at the kneefatigue point strength 𝐴𝐴𝐴𝐴 A,tc𝑏𝑏𝑏𝑏 =2. Theat the 𝐴𝐴𝐴𝐴difference𝑡𝑡𝑡𝑡 knee: point is theσA,tc . The difference is the : = 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 , 𝜏𝜏𝜏𝜏𝐴𝐴𝐴𝐴=𝑡𝑡𝑡𝑡 → ,𝑇𝑇𝑇𝑇𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝜎𝜎𝜎𝜎𝑐𝑐𝑐𝑐 ,𝑐𝑐𝑐𝑐ℎ𝐴𝐴𝐴𝐴𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐√𝑐𝑐𝑐𝑐 𝜏𝜏𝜏𝜏𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴, 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑡𝑡𝑡𝑡 →: =𝜎𝜎𝜎𝜎𝑒𝑒𝑒𝑒1𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐−𝜎𝜎𝜎𝜎=𝑀𝑀𝑀𝑀2+𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒 𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝜎𝜎𝜎𝜎 1 hypothesis, red circle: torsion, green circle: bending)stress state, (bending:, 1Dstress stress state state, (bending: torsion: 1D 2D 𝜎𝜎𝜎𝜎stress stress𝜏𝜏𝜏𝜏 state, state).→ 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅torsion: 𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅 2D𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 stress𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 state).𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 P Peened Peening as cleaning operation 𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 𝐴𝐴𝐴𝐴 𝑡𝑡𝑡𝑡 𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 , =𝐴𝐴𝐴𝐴 𝑡𝑡𝑡𝑡3 , 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 2 2 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 : 1 2 𝜎𝜎𝜎𝜎 , =2√ 𝜏𝜏𝜏𝜏, →=𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑀𝑀𝑀𝑀 +𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅 𝑒𝑒𝑒𝑒 𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅,𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐=ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝜏𝜏𝜏𝜏,𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ: →𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑇𝑇𝑇𝑇𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠=𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎 𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠1 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅 2𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅1𝑐𝑐𝑐𝑐 2𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐: 𝜎𝜎𝜎𝜎 = 𝜎𝜎𝜎𝜎 −𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 𝜏𝜏𝜏𝜏𝐴𝐴𝐴𝐴 𝑡𝑡𝑡𝑡 → 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝜎𝜎𝜎𝜎𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒�𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎1 𝜎𝜎𝜎𝜎 −𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 2 2 =2𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 𝐴𝐴𝐴𝐴 𝑡𝑡𝑡𝑡 : = 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 S Sized 𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 , , ==𝐴𝐴𝐴𝐴 𝑡𝑡𝑡𝑡,3 , , = , , 𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏𝜎𝜎𝜎𝜎 𝐴𝐴𝐴𝐴, 𝑡𝑡𝑡𝑡 𝜏𝜏𝜏𝜏:𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 →= =𝑒𝑒𝑒𝑒: 1𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑀𝑀𝑀𝑀 2+𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅:𝑒𝑒𝑒𝑒 𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐=𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 1𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 𝜏𝜏𝜏𝜏 → 𝑇𝑇𝑇𝑇𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠�𝜎𝜎𝜎𝜎𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠1 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝜎𝜎𝜎𝜎2𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒−𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅1𝑅𝑅𝑅𝑅𝜎𝜎𝜎𝜎𝑐𝑐𝑐𝑐2𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝜎𝜎𝜎𝜎ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝜏𝜏𝜏𝜏𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐√𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐→𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝜎𝜎𝜎𝜎𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅−𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 2 2 , 𝐴𝐴𝐴𝐴=2𝑏𝑏𝑏𝑏 𝐴𝐴𝐴𝐴, 𝑡𝑡𝑡𝑡 , =2 , 𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 , =𝐴𝐴𝐴𝐴 𝑡𝑡𝑡𝑡3 : , 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒= 1 : = 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 : 1 2 tenance effort are lower. As a result, boundary conditions,𝜎𝜎𝜎𝜎𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 𝜏𝜏𝜏𝜏√ 𝜏𝜏𝜏𝜏→𝐴𝐴𝐴𝐴 to𝑡𝑡𝑡𝑡𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅→ the𝑐𝑐𝑐𝑐=𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐 material𝑅𝑅𝑅𝑅𝑀𝑀𝑀𝑀𝑅𝑅𝑅𝑅+𝑅𝑅𝑅𝑅𝜎𝜎𝜎𝜎𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝐴𝐴𝐴𝐴𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝜏𝜏𝜏𝜏𝑒𝑒𝑒𝑒 𝐴𝐴𝐴𝐴𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑡𝑡𝑡𝑡 𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐→𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐 𝑅𝑅𝑅𝑅𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅ℎ𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑦𝑦𝑦𝑦𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝜏𝜏𝜏𝜏𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐ℎℎ𝑒𝑒𝑒𝑒𝑦𝑦𝑦𝑦𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅→𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑇𝑇𝑇𝑇𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠ℎ𝑒𝑒𝑒𝑒𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝜎𝜎𝜎𝜎�𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝜎𝜎𝜎𝜎𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐1𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅ℎ𝑒𝑒𝑒𝑒𝑦𝑦𝑦𝑦𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅𝑦𝑦𝑦𝑦𝑅𝑅𝑅𝑅2𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐−𝜎𝜎𝜎𝜎𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑠𝑠𝑠𝑠1𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝜎𝜎𝜎𝜎𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐2 𝜎𝜎𝜎𝜎ℎ𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝜎𝜎𝜎𝜎1𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 −𝜎𝜎𝜎𝜎 Solution treated and = 3 = 3 : : ST For austenitic stainless steels malfunctions of a flat bending fatigue approximation𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 , (elastic𝜏𝜏𝜏𝜏𝐴𝐴𝐴𝐴 𝑡𝑡𝑡𝑡 → ,𝑇𝑇𝑇𝑇𝑠𝑠𝑠𝑠 or𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 elastic/𝑠𝑠𝑠𝑠 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝜎𝜎𝜎𝜎2𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅, 𝑒𝑒𝑒𝑒2𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝜏𝜏𝜏𝜏𝑐𝑐𝑐𝑐𝐴𝐴𝐴𝐴 𝑐𝑐𝑐𝑐𝑡𝑡𝑡𝑡 𝑐𝑐𝑐𝑐→𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅,𝑇𝑇𝑇𝑇𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠ℎ𝜎𝜎𝜎𝜎𝑦𝑦𝑦𝑦𝐴𝐴𝐴𝐴𝑠𝑠𝑠𝑠𝑦𝑦𝑦𝑦𝑠𝑠𝑠𝑠𝑏𝑏𝑏𝑏𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐ℎ𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅√𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝜏𝜏𝜏𝜏𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝐴𝐴𝐴𝐴𝑒𝑒𝑒𝑒𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅𝑡𝑡𝑡𝑡𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅→𝑐𝑐𝑐𝑐=𝑐𝑐𝑐𝑐𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅1𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑀𝑀𝑀𝑀−𝜎𝜎𝜎𝜎+𝑅𝑅𝑅𝑅ℎ𝑅𝑅𝑅𝑅𝑦𝑦𝑦𝑦2𝑅𝑅𝑅𝑅𝑦𝑦𝑦𝑦𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑒𝑒𝑒𝑒ℎ𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑒𝑒𝑒𝑒 𝑅𝑅𝑅𝑅𝜎𝜎𝜎𝜎𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅1𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐−𝜎𝜎𝜎𝜎ℎ𝑦𝑦𝑦𝑦2𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝜎𝜎𝜎𝜎𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 quenched �𝜎𝜎𝜎𝜎1 𝜎𝜎𝜎𝜎2 −𝜎𝜎𝜎𝜎1𝜎𝜎𝜎𝜎2 testing machine will be covered plastic material)𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏 √or𝜏𝜏𝜏𝜏 regarding𝐴𝐴𝐴𝐴 𝑡𝑡𝑡𝑡 →=𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑀𝑀𝑀𝑀+ 𝑅𝑅𝑅𝑅the𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝐴𝐴𝐴𝐴𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝐴𝐴𝐴𝐴𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑡𝑡𝑡𝑡𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝜎𝜎𝜎𝜎𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒2 2 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 𝜎𝜎𝜎𝜎 √ 𝜏𝜏𝜏𝜏 →=𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑀𝑀𝑀𝑀+𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅�𝑒𝑒𝑒𝑒 𝜎𝜎𝜎𝜎𝑅𝑅𝑅𝑅1𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝜎𝜎𝜎𝜎𝑠𝑠𝑠𝑠2𝑅𝑅𝑅𝑅−𝜎𝜎𝜎𝜎𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 ℎ1𝑦𝑦𝑦𝑦𝜎𝜎𝜎𝜎𝑦𝑦𝑦𝑦2𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝜎𝜎𝜎𝜎 Solution treated, earlier. In our case, five similar incorporation of process specific2 2 2 2 STA For aluminium alloys �𝜎𝜎𝜎𝜎1 𝜎𝜎𝜎𝜎2 −𝜎𝜎𝜎𝜎1𝜎𝜎𝜎𝜎2 �𝜎𝜎𝜎𝜎1 𝜎𝜎𝜎𝜎2 −𝜎𝜎𝜎𝜎1𝜎𝜎𝜎𝜎2 quenched and aged resonance flat bending fatigue testing effects (implementation of residual The parameters are designated as: STT Steam treated machines of the type ‘RUMUL’, as stresses sR). Agreement between

shown in Fig. 6 guarantee a consistent the numerical and the experi- seq: Equivalent stress according Table 1 Chosen prefixes and suffixes for the internal coding of the datasets fatigue testing procedure. mental setup should be as close as to the chosen equivalent stress possible. hypothesis Team The metallurgical explanation for the findings from Beiss [13]. Figs. 7 a constant value of s =0.023 is s1 and s2: Principal stresses of s All the conflicts mentioned above can the 2D stress state this observation can be adopted from and 8 demonstrate the expected assumed for all sintered PM steels, be avoided by using a proper fatigue Good simplifications, valid grey cast iron [7]. Flat and randomly behaviour. independent of their sintered density s : Bending fatigue strength team structure, with an expert from similarities and exact A,b orientated graphite flakes exhibit the Other examples of good simpli- r, loading ratio R, stress concentra- at the knee point the simulation (FEA), fatigue, testing, derivations same interval stress concentration fications and valid similarities are tion factor Kt or heat treatment sA,tc: Tension/compression material and process departments. effect (internal peak stress speak) described in [13]. At this time, there processing history [14]. A similar Potential harmonisation demands In-house testing efforts can be fatigue strength at the knee for pure tension and torsion. An is no significant influence on the simplification can be applied in terms point could be related to the required output reduced through existing knowledge. analogue behaviour can be expected material scatter (expressed over the of the support factor nc. According

variables (stresses s and strains e), An example is the required tA,t: Torsion fatigue strength at for sintered PM steels with randomly logarithmic standard deviation of the to [4] the fatigue notch factors Kf of

to the correct approximation of the investigation of the equivalent the knee point orientated pores, which might explain strength ss) detectable. Therefore, sintered PM steels are comparable

This effect was also found in sintered Loading ratio Sintered density r Stress concentration factor Example preparation of a (1) (1) PM steels [4]. The Wöhler line s-N Stress concentration factor Balshin parameters R (g/cm³) Kt (specimens’ geometry) dataset Loading ratio is described through the widely used (1) (1) R Kt (specimens’ geometry) -1 6.8 7.0 7.2 ~1 (1.04) 1.91 (1) Basquin equation as: P0 (MPa) m In the following, an example dataset 0 6.8 7.0 7.2 ~1 (1.04) ~1 (1.04) 423 4.778 is generated. Moreover, a few general -1 0.5 6.8 7.0 7.2 ~1 (1.04) settings must be set in the ‘Standard = 1 0 ~1 (1.04) 255 4.377 𝑘𝑘𝑘𝑘 SN Engine’ over the dialogue window 𝑁𝑁𝑁𝑁 Table 2 Fatigue testing matrix with focus on the sintered density r range 𝜎𝜎𝜎𝜎𝑚𝑚𝑚𝑚 � � 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 0.5 ~1 (1.04) 178 4.776 ‘DesignLife Configuration Editor’ of The parameters𝑁𝑁𝑁𝑁𝐾𝐾𝐾𝐾 are designated as: according to the Sint D-class (DIN 30910-4) the fatigue software used, in this case -1 1.91 374 7.487 s : (tension/compression or nCode DesignLife (good simplifica- A σA: (tension/compressionbending) or bending) fatigue fatiguestrength strength at the at theTable 3 Derived Balshin parameters P and m. P indicates the fully dense tions, valid similarities and exact deri- 0 0 knee point knee point (f=0) property at the estimated full density of r =7.814 g/cm³. The exponent m vations) to apply the chosen equivalent 0 for a wide range of powder composi- the internal dataset names in the σ indicates the strength of the density dependency, especially if compared with a: Stress amplitude sa: Stress amplitude tions (chemical compositions). A in-house database consist of a stress seq, the required survival NK: Cut-off point the linear rule of mixtures probability P , the used mean stress NK: Cut-off point significant effect of the sintered prefix (Table 1), which defines the s k: Slope density r or the hardness H could processing route, the nominal sm correction model and the used k: Slope not be found in the investigated static powder composition (chemical stress gradient c* correction model. Once the twelve Wöhler lines s-N Two free parameters (P0 and m) was defined, the fitted parameters, = 1 strength range from σ =430 MPa to composition), a suffix, which It is essential to understand that a u are generated,𝑘𝑘𝑘𝑘 the resulting fatigue can be estimated by regression if P0 and m, are only valid for this triple harmonised fatigue testing program, 𝑁𝑁𝑁𝑁 σu=1177 MPa. defines the heat treatment 𝑚𝑚𝑚𝑚 𝐴𝐴𝐴𝐴 r strength𝜎𝜎𝜎𝜎 � at the� knee𝜎𝜎𝜎𝜎 point sA values the full density 0 is known. There constellation. and proper simplifications and good 𝐾𝐾𝐾𝐾 condition (or any other secondary and the other𝑁𝑁𝑁𝑁 parameters of the are several methods to estimate the We will demonstrate the data prep- process), the applied sintering similarities, are needed at this position Wöhler lines s-N (the cut-off point full density r0. The easiest method aration for a typical high-strength Coding and designations temperature and the sintered to input the required parameters. is to neglect the alloying elements sintered PM steel, Ancorsteel FLD-49 σA: (tension/compressionNK and the or slopebending) k) must fatigue be written strength at the density r. In the case of a nCode DesignLife (formerly by assuming the full density r of HP + 0.65% C. This is a water-atom- knee point in a density-dependent manner 0 The dataset name should incorporate tempering treatment that was not MSC-Fatigue) is one of the most pure iron as representative (in this ised molybdenum pre-alloyed steel σ to generate a continuous density- performed, the suffix ‘T’ can be developed fatigue assessment a: Stress amplitude as much as possible of the material dependent dataset, which predicts case r0=7.86 g/cm³). Another method powder, which was subsequently programs [15] for the general purposeNK : Cut-off point and process information. Therefore, removed. the effect of the sintered density r is to melt a porous specimen of nickel and copper diffusion-alloyed. together with its competitors FEMFATk: Slope over a wide range. the relevant powder composition The carbon content of C=0.65% [16], fe-safe and WINLIFE. nCode This is by far the most important (chemical composition) with a plasma (=graphite addition) was mixed DesignLife was chosen due to its step to generate a systematic torch head to a melting (or welding) in-house. The nominal composition interface to our FEA-solver. A few in-house database, since a typical bead of full density r0. is Fe + 4% Ni + 2% Cu + 1.5% Mo + other commercial software packages 40000 sintered density range for r=6.4 g/ Pycnometrical measurements are 0.15% Mn + 0.65% C. The compacted are on the market for special machine FLD-49HP + 0.65 % C, cm³ to r >7.2 g/cm³ must be covered also possible if the effect of closed specimens, according DIN EN ISO elements, for example KISSsoft for 3500 Radevormwald 963, ϑ=1120 °C, t=23 min, (Sint C-class to Sint E-class of DIN pores of the porous body is neglected. 3928, were sintered at J=1120°C for ∆ϑ/∆t =-44 °C/min (0 % cooling), gears, bearings and shafts. A general = 00 800 °C-600 °C 30910-4). However,𝑚𝑚𝑚𝑚 the sintered We calculate the theoretical full an isothermal sintering time of t=23 95 % N + 5 % H + 200 l/h CH , FLD-49HP + 0.65 % C, 30000 2 2 4 overview of existing software packages 0 𝜌𝜌𝜌𝜌 density𝑃𝑃𝑃𝑃 𝑃𝑃𝑃𝑃range� � from r=6.8 g/cm³ to density r0 by the specific weights min in a hydrogen-nitrogen protec- Radevormwald 963, ϑ=1120 °C, t=23 min, bending loading, nominal stress system 0 0 (as of 2007) can be found in [17]. In this equation the following abbreviations𝜌𝜌𝜌𝜌 are used: of the used alloying elements as is tion atmosphere (95% N + 5% H ). ∆ϑ/∆t =-44 °C/min (0 % cooling), 2500 r=7.2 g/cm³ (Sint D-class) has the 2 2 800 °C-600 °C ) Three different sintered densities r 95 % N + 5 % H + 200 l/h CH , highest importance for structural PM done during the estimation of the The cooling-rate DJ/Dt was meas- 00 P a 2 2 4 are always achieved. Their magnitudes 20000 P: Material propertycomponents. which is affected Therefore, by thisthe porosityclass f theoretical density of compacted (but ured over the thermocouple sintering ( M bending loading, nominal stress system (MPa)

A A were carefully adjusted by previ- 0 0 σ P : Fully dense material property (f=0) not sintered) compacts. Certainly, profileJ (t) and was calculated as σ ) was split for the definition of the 1500 ously performed sintering trials to ρ: Sintered density this procedure totally neglects the the best line slope between J=800°C P a fatigue testing matrix from Table 2. 00 investigate the resulting shrinkage or ( M K =1.04, R=-1 ρ0: Full density This rigorous procedure was adopted mixed crystal formation, the solubility and J=600°C above the martensite 10000 t A growth. A typical fatigue testing matrix σ K =1.04, R=0 from Beiss, who has introduced the of the (high volume) carbon and the starting temperature Ms and was 0 t is shown below. 500 K =1.04, R=0.5 Balshin power-law in the German- resulting microstructure with its found to be DJ/Dt800°C-600°C=-44°C/min t In our programmes, we test only the Kt=1.04, R=-1 specific volume resulting in lower full (achieved with the minimum speed of 00 Kt=1.91, R=-1 speaking PM community: 0 K0 =1.04, R=0 notched condition at a loading ratio t density r0 values. It should be kept the cooling fan, 0% cooling). 6.7 6.8 6.9 7.00 7.1 7.2 7.3 0 K =1.04, R=0.5 of R=-1.σ This isρ a good compromise4.778 t Balshin fit (least square for all): A=423 MPa*( /7.814 g/cm³) in mind that the sintered density r The full density r0 of Ancorsteel 3 K =1.91, R=-1 ρ (g/cm(g/cm³) to save testing time and to reduce4.377 = t Balshin fit (least square for all): σ =255 MPa*(ρ/7.814 g/cm³) 𝑚𝑚𝑚𝑚 is affected by the cooling-rate DJ/Dt FLD-49 HP + 0.65% C was estimated, 0 A the testing effort. The highest4.77 6drop of 𝜌𝜌𝜌𝜌 0 Balshin fit (least square for all): σ =178 MPa*(ρ/7.814 g/cm³) 0 since it controls the ferrite-pearlite, with the specific weights of the used 3 4.778 4.778 A 𝑃𝑃𝑃𝑃 𝑃𝑃𝑃𝑃 � � BalshinBalshin fit fi t(least (leas squaret squa rfore f oall):r a lσl)A:=423 σ =4 MPa*(23 MPρ/7.814a*(ρ/7 g/cm.814 g) /cm³) the Haigh damage line in the positive 0 A 7.487 bainite and martensite volume alloying elements with r =7.86 g/ ρ σ ρ In this equation𝜌𝜌𝜌𝜌 the following Fe (g/cm³) Ba3ls4.377hin fit4 .(3l7e7 ast square for all): A=374 MPa*( /7.814 g/cm³) In this equation the following abbreviations are used: BalshinBalshin fit fi t(least (leas squaret squa rfore f oall):r a lσl)A:=255 σ =2 MPa*(55 MPρ/7.814a*(ρ/7 g/cm.814 g) /cm³) mean stress sm domain, due to the A abbreviations are used: fractions. The advantage is that cm³, rNi=8.86 g/cm³, rMo=10.22 g/ 3 4.776 4.776 fatigue notch factor Kf, can be expected BalshinBalshin fit fi t(least (leas squaret squa rfore f oall):r a lσl)A:=178 σ =1 MPa*(78 MPρ/7.814a*(ρ/7 g/cm.814 g) /cm³) a common full density r value is cm³, r =8.93 g/cm³, r =7.30 g/cm³ A P: Material property whichP: Material is affected property by which the porosity is f 0 Cu Mn 3 4.487 7.487 at a loading ratio of R=-1 [9]. For hard BalshinBalshin fit fi t(least (leas squaret squa rfore f oall):r a lσl)A:=374 σ =3 MPa*(74 MPρ/7.814a*(ρ/7 g/cm.814 g) /cm³) used for compaction-related ques- and rC=2.25 g/cm³, to be r0=7.814 g/ A P0: Fully dense materialaffected property by the (f=0) porosity f and brittle materials, both Haigh tions, as well as for the fatigue data cm³. This value and the derived three P : Fully dense material property Fig. 9 Evolution of the cyclic properties as function of sintered density r of damage lines (unnotched vs. notched)ρ: Sintered density 0 preparation. However, the quality data pairs were used for the data (f=0) Ancorsteel FLD-49HP + 0.65% C with a sintered density of r=6.8 g/cm³, r=7.0 will run in a parallel manner, while, ρfor0: Full density of the data representation over the fitting as shown in Fig. 9. The found g/cm³ and r=7.2 g/cm³ (bending loading mode, survival probability: Ps=50%), more ductile materials, Kf decreases r: Sintered density Balshin power-law (expressed over Balshin parameters are summarised the dashed lines show the curve progression with a constant Balshin exponent with an increasing mean stress s due 2 m r0: Full density the goodness of fit R value) is not in Table 3. With these parameters, an of m=5 with the intermediate sintered density of r=7.0 g/cm³ as base point to plastic yielding in the notch root. m: Characteristic exponent affected. Once a full density r0 value inter- and extrapolation over a wide

40000 density r is underestimated at higher not have enough explanation power. 2.00 K =1.04, ρ=7.2 g/cm³ t loading ratios R. In general, the findings are in accord- ρ σ =7.2 g/cm³, u=849 MPa 3500 K =1.04, ρ=7.0 g/cm³ 1.9 t Due to the resulting different ance with the recommendations ρ σ =7.0 g/cm³, u=724 MPa K =1.04, ρ=6.8 g/cm³ t Balshin exponents, m(Kt=1.04, from [4]. Therefore, this material is 1.8 ρ=6.8 g/cm³, σ =650 MPa 30000 u K =1.91, ρ=7.2 g/cm³ t R=-1)=4.778, m(Kt=1.04, R=0)=4.377 described with the general support 1.7 Support factor (Hück): n =1+0.311 mm*χ*^0.617 R=-1 χ K =1.91, ρ=7.0 g/cm³ 2500 t and m(Kt=1.04, R=0.5)=4.776, the factor equation for sintered PM χ

) Support factor (Hück): n =1+0.321 mm* *^0.652 1.6 χ ( ) K =1.91, ρ=6.8 g/cm³ mean stress sensitivities M (here: M steels: (1)

2 f f P a t χ Support factor (Hück): nχ=1+0.226 mm* *^0.268 K

200 /K 00 /

and M ) vary with the sintered density t 1.5 3 t ( M (MPa)

R=0 A K A

σ r . as shown in Table 4. The reason = σ = K = =1+ × = 1 + 0.329 × χ 150 χ 1.4 0 R=0.5 n for this behaviour is unknown and 𝑡𝑡𝑡𝑡 ∗𝑏𝑏𝑏𝑏 ∗0 736 n FLD-49HP + 0.65 % C, FLD-49HP + 0.65 % C, 𝜒𝜒𝜒𝜒 𝐾𝐾𝐾𝐾 displays the random character of 𝑐𝑐𝑐𝑐 𝑓𝑓𝑓𝑓 𝑅𝑅𝑅𝑅 𝜒𝜒𝜒𝜒 𝜒𝜒𝜒𝜒 1.3 Radevormwald 963, ϑ=1120 °C, t=23 min, 10000 Radevormwald 963, ϑ=1120 °C, t=23 min, .𝐾𝐾𝐾𝐾 = =1+ × = 1 + 0.329 × ∆ϑ/∆t =-44 °C/min (0 % cooling), ∆ϑ/∆t =-44 °C/min (0 % cooling), fatigue testing. Even if all parameters 800 °C-600 °C 800 °C-600 °C 𝑡𝑡𝑡𝑡 𝑏𝑏𝑏𝑏 0 736 1.2 𝐾𝐾𝐾𝐾 ∗ ∗ 95 % N + 5 % H + 200 l/h CH , 50 95 % N + 5 % H + 200 l/h CH , were adjusted, minor differences and 𝜒𝜒𝜒𝜒 2 2 4 0 2 2 4 𝑐𝑐𝑐𝑐 𝑓𝑓𝑓𝑓 𝑅𝑅𝑅𝑅 𝜒𝜒𝜒𝜒 𝜒𝜒𝜒𝜒 𝐾𝐾𝐾𝐾 nχ: Support factor 1.1 bending loading, nominal stress system bending loading, nominal stress system inconsistencies might occur from In this equation the following Kt: Stress concentration factor 0 time to time. The recommendation abbreviations are used: 1.00 --2500 --20000 --1500 --10000 --500 0 500 10000 1500 20000 2500 30000 3500 40000 Kf: Fatigue notch factor 0.000 00.5 1.00 1.5 2.00 2.5 3.00 3.5 4.00 to investigate various nsinteredχ: densiSupport- factor n : Support factor a: Hückc coefficient * σσm (MPa) (1/mm) m (MPa) ties r becomes justifiedKt: to create anStress concentration factor χχ* (1/mm) b: HückKt :exponent Stress concentration factor Fig. 10 Haigh mean stress diagram and Haigh damage lines of Ancorsteel average of the findings.Kf: Fatigue notch factor χ*: Relative stress gradient Fig. 11 Support factor of Ancorsteel FLD-49HP + 0.65% C with a sintered a: Hück coefficient Kf: Fatigue notch factor FLD-49HP + 0.65% C with a sintered density of r=6.8 g/cm³, r=7.0 g/cm³ and Fig. 11 shows the derived notch density of r=6.8 g/cm³, r=7.0 g/cm³ and r=7.2 g/cm³ (bending loading mode, b: Hück exponent a: Hück coefficient r=7.2 g/cm³ (bending loading mode, survival probability: Ps=50%) sensitivities. The found Hück survival probability: Ps=50%) exponent b for the sinteredχ*: density Relative stress gradient b: Hück exponent of r=6.8 g/cm³ seems to be too c*: Relative stress gradient sintered density r range is possible. diate sintered density of r=7.0 g/cm³ low. It should be kept in mind that For a correct approximation of the The raw data (Wöhler lines s-N) can shows a slightly different progres- the derived parameters are based HCF domain, the cut-off points Austria. The development goes back local component Wöhler line be found in Figs. 24–29, contained in sion. As a consequence, the mean on at least two Wöhler lines s-N. NK and the slopes k of the Wöhler to the early 1980s [19]. The main s-N the appendix to this article. stress sensitivity M2(r=7.0 g/cm³) Therefore, the individual errors are lines s-N must also be written focus was the incorporation of the The derived Haigh damage lines seems to be lower than expected. On accumulated (error propagation law), fGR, sf: Influence factor of the in a density-dependent manner. relative stress gradient c* and its are shown in Fig. 10. The interme- the other hand, the effect of sintered meaning an individual finding does relative stress gradient c* on Unfortunately, the potential progres- effects on the Wöhler line s-N [20]. the slope of the local component sion of the Wöhler lines s-N of Since an in-house nomenclature was Wöhler line s-N sintered PM steels as a function of developed for the commercial fatigue N : Cut-off point of the local σ cf,C A the sintered density r, loading ratio software FEMFAT, it must be clarified s ρ σu σA(R=0) σA(R=0.5) (1) (1) (1) (1) (1) (1) component Wöhler line -N (R=-1) M1 M2 M3 M4 NK k R and stress concentration factor K that a few parameters are coded (g/cm³) (MPa) (MPa) (MPa) t N : Cut-off point of the mate- (MPa) has never been investigated in detail. twice (k=k and N =N ). The local cf,M M cf,M K rial Wöhler line s-N at a loading This is a relic from the chronically low component Wöhler line s-N (index: 6 354 120 80 50 0 -0.492 -0.420 0 31798 -7.6820 ratio of R=-1 number of fatigue specimens used C) is synthesised from the material 6.1 383 130 86 55 0 -0.502 -0.410 0 62582 -7.6127 for the HCF domain – for a long time, Wöhler line s-N (index: M) through a These two equations enforce the 6.2 414 140 93 59 0 -0.512 -0.400 0 93367 -7.5434 the derivation of the fatigue strength few correction factors as: shifting of the Wöhler line s-N as at the knee point s (endurance limit) described above. With an increasing 6.3 447 151 99 64 0 -0.522 -0.390 0 124151 -7.4741 A had a higher importance. From a 2 1 notch sharpness, the slope k will 6.4 481 163 106 69 0 -0.531 -0.381 0 154935 -7.4048 very general overview [18], it can be = + 2 become steeper and the cut-off point 1 , ⎛ ,𝑅𝑅𝑅𝑅𝑀𝑀𝑀𝑀 −1+𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐾𝐾𝐾𝐾 ⎞ concluded that the slope k is affected 𝐶𝐶𝐶𝐶 , N will be shifted to smaller values 6.5 518 176 114 74 0 -0.541 -0.372 0 185720 -7.3355 𝑅𝑅𝑅𝑅 ⎜ 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐾𝐾𝐾𝐾3 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐾𝐾𝐾𝐾 ⎟ 𝑚𝑚𝑚𝑚 𝑠𝑠𝑠𝑠𝑓𝑓𝑓𝑓 K 𝑓𝑓𝑓𝑓𝐺𝐺𝐺𝐺𝑅𝑅𝑅𝑅 𝑠𝑠𝑠𝑠𝑓𝑓𝑓𝑓 − 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐾𝐾𝐾𝐾3 𝑓𝑓𝑓𝑓 by the stress concentration factor Kt 𝑓𝑓𝑓𝑓1 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 (shifting to the left) [16]. The effect . 6.6 557 189 122 79 0 -0.550 -0.363 0 216504 -7.2662 ⎝ . ⎠ of the loading ratio R is considered (or the relative stress gradient c*). 10 3 6 , = , �6 8 . � through the influence factor of the 6.7 599 203 130 85 0 -0.560 -0.354 0 247288 -7.1969 With an increasing notch sharpness, . 𝑘𝑘𝑘𝑘𝐶𝐶𝐶𝐶 10 the slope k will become steeper and 𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡 𝐶𝐶𝐶𝐶 𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡 𝑀𝑀𝑀𝑀 3 6 mean stress s on the slope of the 𝑁𝑁𝑁𝑁 𝑁𝑁𝑁𝑁 �6 8 � m 6.8 642 218 139 92 0 -0.569 -0.346 0 278072 -7.1276 𝑘𝑘𝑘𝑘𝑀𝑀𝑀𝑀 the cut-off point NK will be shifted to local component Wöhler line s-N. 6.9 689 233 148 98 0 -0.578 -0.338 0 308857 -7.0583 smaller values (shifting to the left). In these equations, the parameters The FKM guideline assumes a are coded as follows: constant cut-off point N and a 7 737 250 158 105 0 -0.587 -0.331 0 339641 -6.9890 The most developed method K for adjusting the Wöhler line s-N k : Slope of the local component constant slope k for the local compo- 7.1 789 268 168 113 0 -0.596 -0.323 0 370425 -6.9197 C parameters, the fatigue strength at Wöhler line s-N nent Wöhler line s-N independent of kC: Slope of the local component Wöhler line σ-N 7.2 843 286 178 120 0 -0.605 -0.316 0 401210 -6.8504 the knee point sA, the cut-off point the individual loading ratio R and the kM: Slope ofk theM: Slopematerial of Wöhler the material linie σ-N Wöhler at a loading ratio of NK and the slope k, was developed stress concentration factor Kt. This 7.3 900 306 189 129 0 -0.614 -0.309 0 431994 -6.7811 R=-1 linie s-N at a loading ratio of by Eichlseder for the commercial differentiates between aluminium IFK2: Material R=-1parameter Table 4 Extracted datasets in Dr=0.1 g/cm³ step for the sintered density range from r=6.0 g/cm³ to r=7.3 g/cm³. The fatigue software FEMFAT [16].IFK3: Material parameter and iron-based materials (steels IFK2: Material parameter The origin of that work wasfm,sf the: Influence factor of the mean stress σm on the slopeand of the cast iron) and austenitic steels, bending fatigue strength at the knee point sA values must be corrected as described in [10] to approximate the relative local componentIFK3: Material Wöhler lineparameter σ-N stress gradient of c*=0 mm-1. This is needed for the further relative stress gradient c* correction over the support factor development of an in-house fatigue welded and non-welded compo- assessment FEA-postprocessor at f : Influence factor of the mean nents, surface condition (surface- nc. The mean stress sensitivities of M1=M4=0 are recommendations from the FKM guideline [11]. In reality, an asymptotic m,sf behaviour is more realistic Steyr-Daimler-Puch AG in Steyr, stress sm on the slope of the hardened materials) and in regard to

three loading ratios R) show the evaluation. The input variables were Coding +1 -1 (1) Cut-off point opposite behaviour. normalised between +1 and -1 to Component Slope k (1) Reference NK Sintered density r (g/cm³) 7.2 6.7 use the resulting intercepts as mean • Seven out of eight datasets Variable valve Max.: -7.4676 Max.: 967473 values. Intermediate input variables Loading ratio R (1) 0.5 -1 (unnotched bending fatigue timing stator Min.: -7.4676 Min.: 967473 [29] specimen according to DIN EN were linearly interpolated. The used Stress concentration factor K (1) 1.91 1.04 sprocket (VVT) Mean: -7.4676 Mean: 967473 t ISO 3928, flat bending loading coding is shown in Table 5. The resulting multilinear regres- Max.: -5.534 Max.: ~1000000 Table 5 DOE coding of the used input variables to approximate the slope k and mode, stress concentration Adapter control r sion term for the slope k is: Min.: -6.787 Min.: ~1000000 [30] the cut-off point NK as function of the sintered density , loading ratio R and factor Kt=1.04, averaged over valve Mean: -6.091 Mean: ~1000000 stress concentration factor Kt three loading ratios R) show that ( , , , ) Max.: -5.7318 Max.: 599242 the slope k increases with an ( , , , ) = 7.3221 + 0.5559 0.5851Injector+ 0.2163 clamp Min.: -5.7318 Min.: 599242 [31] increasing loading ratio R. =𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅7𝜌𝜌𝜌𝜌.3221𝐾𝐾𝐾𝐾𝑡𝑡𝑡𝑡 𝑓𝑓𝑓𝑓+𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 0.𝑏𝑏𝑏𝑏5559𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐0.𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐5851 𝑚𝑚𝑚𝑚+𝑐𝑐𝑐𝑐 0.𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏2163 𝑡𝑡𝑡𝑡 the loading mode (normal stresses s factor Kt=1.04, averaged over ( , , , 𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 )𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾 𝑓𝑓𝑓𝑓𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑚𝑚𝑚𝑚𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 𝑡𝑡𝑡𝑡 Mean: -5.7318 Mean: 599242 • One out of eight datasets − 𝑅𝑅𝑅𝑅� 𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾 or shear stresses t). For non-welded three loading ratios R) show that = 7.3221 + 0.5559 0.The5851 resulting+ 0.−2163 multilinear regression𝑅𝑅𝑅𝑅� term𝜌𝜌𝜌𝜌 for the cut𝐾𝐾𝐾𝐾-𝑡𝑡𝑡𝑡off point NK is: (unnotched bending fatigue𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾𝑡𝑡𝑡𝑡 𝑓𝑓𝑓𝑓𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐T𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐he resulting𝑚𝑚𝑚𝑚𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 multilinear regression term for the cut-off point NK is: Max.: -6.1460 Max.: 1955401 and non-surface-hardened steel the slope k increases with an ( , , , 𝑡𝑡𝑡𝑡 ) specimen according to DIN EN − ( 𝑅𝑅𝑅𝑅, �, , 𝜌𝜌𝜌𝜌 ( , 𝐾𝐾𝐾𝐾, , ) ) Gears Min.: -13.9805 Min.: 304216 [32] components, the cut-off point is set increasing sintered density r. The resulting multilinear regression term for the( cut, ,-off, pointThe NresultingK is: = multilinear7.3221 +) 0. 5559regres- 0.5851 + 0.2163 = 7.3221𝑡𝑡𝑡𝑡 + 0.5559= 6104900.5851 45056+ 0.2163 3675 + 67679 Mean: -8.4084 Mean: 804830 6 ISO 3928, flat bending loading( , , , )𝑡𝑡𝑡𝑡 𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 𝜌𝜌𝜌𝜌𝐾𝐾𝐾𝐾 𝐾𝐾𝐾𝐾 𝑓𝑓𝑓𝑓𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑡𝑡𝑡𝑡 𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑚𝑚𝑚𝑚𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 as ND,s=ND,t=10 . The corresponding 𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾 𝑓𝑓𝑓𝑓𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅sion𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏=𝑁𝑁𝑁𝑁 term𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐6𝑏𝑏𝑏𝑏10490𝑅𝑅𝑅𝑅𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝜌𝜌𝜌𝜌 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐for𝐾𝐾𝐾𝐾 the𝑓𝑓𝑓𝑓45056𝑒𝑒𝑒𝑒𝑚𝑚𝑚𝑚𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 cut-off𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏 𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐 point3675𝑏𝑏𝑏𝑏 𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 NK+ 67679 is:𝑚𝑚𝑚𝑚𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 • One out of eight datasets 𝐾𝐾𝐾𝐾 𝑡𝑡𝑡𝑡 − 𝑅𝑅𝑅𝑅� 𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾𝑡𝑡𝑡𝑡 mode, stress concentration ( , , , = 7.3221 + 0.5559 𝑁𝑁𝑁𝑁 𝑅𝑅𝑅𝑅 0.)𝜌𝜌𝜌𝜌 5851𝐾𝐾𝐾𝐾 𝑓𝑓𝑓𝑓𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅+𝑏𝑏𝑏𝑏 0.𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅2163𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑚𝑚𝑚𝑚𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 𝑡𝑡𝑡𝑡 𝑡𝑡𝑡𝑡 Max.: -4.0000 Max.: 5000000 slopes k are affected by the loading 𝑡𝑡𝑡𝑡 The resulting− multilinear regression𝑅𝑅𝑅𝑅� term−𝜌𝜌𝜌𝜌 for the𝑅𝑅𝑅𝑅 cut�𝐾𝐾𝐾𝐾-off point𝜌𝜌𝜌𝜌 NK is: 𝐾𝐾𝐾𝐾 (unnotched bending fatigue 𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾 𝑓𝑓𝑓𝑓𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑏𝑏𝑏𝑏=𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅6𝑏𝑏𝑏𝑏10490𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐T𝑏𝑏𝑏𝑏he𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐resulting45056𝑚𝑚𝑚𝑚𝑐𝑐𝑐𝑐 𝑏𝑏𝑏𝑏multilinear𝑏𝑏𝑏𝑏 T3675he very+ regression 67679low coefficients term− for show the𝑅𝑅𝑅𝑅 �cutthat-off the point𝜌𝜌𝜌𝜌 observed NK is:𝐾𝐾𝐾𝐾 slopes𝑡𝑡𝑡𝑡 k and cut-off points factor Kt=1.04, averaged over𝐾𝐾𝐾𝐾 𝑡𝑡𝑡𝑡 The very low coefficients show that𝑡𝑡𝑡𝑡 the observed slopes k and cut-offOldham points coupler Min.: -4.0000 Min.: 5000000 [33] mode. These are defined as sk =-5 specimen according to DIN EN 𝑁𝑁𝑁𝑁 𝑅𝑅𝑅𝑅 𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾 𝑓𝑓𝑓𝑓𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑏𝑏𝑏𝑏−𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑚𝑚𝑚𝑚𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏�N𝑏𝑏𝑏𝑏 K are hardly𝜌𝜌𝜌𝜌 predictable𝐾𝐾𝐾𝐾 with the chosen input variables. Moreover, the The resulting multilinear regression term for the cut-off point( ,NK, is:, ) three loading ratios R) shows the NK− are hardly𝑅𝑅𝑅𝑅( � predictable𝜌𝜌𝜌𝜌 with the𝐾𝐾𝐾𝐾𝑡𝑡𝑡𝑡 chosen input )variables. Moreover, the Mean: -4.0000 Mean: 5000000 (for normal stresses s) and kt=-8 ISO 3928, flat bending loading , adjusted, , coefficients of determination are very low and below The very low coefficients show thatadjusted the observed coefficients slopes of determinationk and cut-off points =are6 10490very low 45056and below3675 + 67679 (for shear stresses t). Similar to opposite behaviour. =𝑁𝑁𝑁𝑁𝐾𝐾𝐾𝐾610490𝑅𝑅𝑅𝑅 𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾𝑡𝑡𝑡𝑡 𝑓𝑓𝑓𝑓45056𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐3675𝑏𝑏𝑏𝑏 𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐+ 67679𝑚𝑚𝑚𝑚𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 Max.: -4,1000 Max.: 2000000 mode, stress concentration NK are hardly predictable( , , , with the chosen 𝑁𝑁𝑁𝑁input𝐾𝐾𝐾𝐾 𝑅𝑅𝑅𝑅 variables.𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾)𝑡𝑡𝑡𝑡 𝑓𝑓𝑓𝑓𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑏𝑏𝑏𝑏Moreover,𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 the 𝑚𝑚𝑚𝑚𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 − 𝑅𝑅𝑅𝑅� 𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾𝑡𝑡𝑡𝑡 the commercial fatigue software factor K =1.04, averaged over • Three out of eightadjusted datasets coefficients of determination= 610490 are45056 very Tlowhe3675 veryand belowlow+ 67679 coefficients − show𝑅𝑅𝑅𝑅 �that the𝜌𝜌𝜌𝜌 observed𝐾𝐾𝐾𝐾 slopes𝑡𝑡𝑡𝑡 Synchroniser k and cut-off points hub Min.: -4.1000 Min.: 1000000 [34] t 𝑁𝑁𝑁𝑁𝐾𝐾𝐾𝐾 𝑅𝑅𝑅𝑅 𝜌𝜌𝜌𝜌 𝐾𝐾𝐾𝐾𝑡𝑡𝑡𝑡 𝑓𝑓𝑓𝑓𝑒𝑒𝑒𝑒𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑏𝑏𝑏𝑏𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅T𝑏𝑏𝑏𝑏he𝑅𝑅𝑅𝑅𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 very𝑒𝑒𝑒𝑒𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 low coefficients𝑚𝑚𝑚𝑚𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 show that the observed slopes k and cut-off points NK are hardly predictable with the chosen input variables. Moreover, the FEMFAT, the nomenclature of the three loading ratios R) shows the (unnotched bending fatigue 𝑡𝑡𝑡𝑡 Mean: -4.1000 Mean: 1500000 NK are− hardly predictable𝑅𝑅𝑅𝑅� 𝜌𝜌𝜌𝜌 with the 𝐾𝐾𝐾𝐾chosen input variables. Moreover, the The very low coefficients show that the observedadjusted slopes coefficients k and cut -ofoff determination points are very low and below FKM guideline is specific and varies opposite behaviour. specimen according to DIN EN adjusted coefficients of determinationThe very low are coefficients very low and show below that Max.: -6.0000 Max.: 2000000 from the common nomenclature in ISO 3928, flat bendingNK are loading hardly predictable with the chosen input variables.the observed Moreover, slopes the k and cut-off • Five out of eight datasets adjusted coefficients of determination are very low and below Synchroniser hub Min.: -6.0000 Min.: 2000000 [35] that work (k=k and N =N ) [11, 21]. s D,s K (unnotched bending fatigue mode, stress concentration points NK are hardly predictable Mean: -6.0000 Mean: 2000000 This recommendation is based on factor K =1.04, averaged over with the chosen input variables. specimen according to DIN EN t Max.: -5.5899 Max.: 1860491 a statistical evaluation from Hück, three loading ratios R) show that Moreover, the adjusted coefficients of ISO 3928, flat bending loading Gears Min.: -7.5534 Min: 768830 [35] Thrainer and Schütz [22, 23]. the cut-off point N increases determination are very low and below mode, stress concentration K Mean: -6.8563 Mean: 1213979 2 From an internal investigation, with an increasing loading ratio Radjusted < 0.03. This means the highest factor Kt=1.04, averaged over according to the fatigue testing Max.: -13.0641 Max.: 1206598 three loading ratios R) show that R. contribution is from the random matrix shown in Table 2, of eight scatter and not from the chosen input Injector clamp Min.: -20.1479 Min.: 1103783 [35] the cut-off point NK decreases • Five out of eight datasets datasets, the following conclu- Mean: -16.6060 Mean: 1155191 with an increasing sintered (unnotched bending fatigue variables (very high residuals). The sions and recommendations can be Max.: -4.5097 Max.: 223279 density r. specimen according to DIN EN two derived multilinear regression summarised: polynomials do not represent the Connecting rod Min.: -4.5097 Min.: 223279 [35] • Three out of eight datasets ISO 3928, flat bending loading conclusions and recommendations Mean: -4.5097 Mean: 223279 • Seven out of eight datasets (unnotched bending fatigue mode, stress concentration from above. The same holds true Max.: -7.9926 Max.: 1033002 (unnotched bending fatigue specimen according to DIN EN factor Kt=1.04, averaged over for the expected effect from the specimen according to DIN EN ISO 3928, flat bending loading three loading ratios R) show the Valve bridge (lever) Min: -10.0266 Min: 851295 [35] stress concentration factor K (or ISO 3928, flat bending loading mode, stress concentration opposite. t Mean.: -9.0096 Mean: 942149 the relative stress gradient c*); the mode, stress concentration factor K =1.04, averaged over Max.: -7.1000 Max.: 2000000 t The effect from the stress concen- scattering is too high. It seems to be Lever Min.: -8.3000 Min.: 2000000 [36] tration factor K (or the relative stress questionable if further attempts to t Mean: -7.5000 Mean: 2000000 gradient c*) was neglected in the correlate the slope k and the cut-off

listing above because its effect was point N with other input variables Table 6 Documented cut-off points NK and slopes k of component Wöhler lines 1E7 1080 o ownwn s- s-NN cur curves,ves K Kt=0 and Kt= not investigated in a fully factorial (e.g. the material or hardness H) are s-N. Similar Max., Min. and Mean values indicate that only one data point was Kt=1.04 and Kt=1.91, R=-1/0/0.5,=-/0/0 manner, since, in our programs, useful. Therefore, the given intercepts given bending loading bending loading, Ps=0 we test only the notched condition k=-7.3221≈-7 and NK=610490≈600000 1000000000000 P =50% s at a loading ratio of R=-1. However, seem to be good representatives 70000000000 0 own component (gears) s-N curves ( ) Kt a systematic effect of the stress for all Wöhler lines s-N derived on with the statistical evaluation from concentration factor Kt≈1) fatigue K (1) 20 own component (gears) s-N K N =00 concentration factor K (or the sintered PM steels. Hück, Thrainer and Schütz [23, 24]. testing conditions. This behaviour N curves,bending loading t 10000000000 P =0 relative stress gradient c*) is not The only rough correlation, which One interesting observation, which was observed several times (case- FatigueFatigue specimensspecimens Kst > 1, ComponentsComponents (gears)(gears) R=0.05, visible. A multilinear regression was could be extracted from the existing is blurred by all the other results as hardened Astaloy CrA + 1% Cu + Nk(|k|)N (k) == 1084770 * |k|k - - 223938 K bending loading, performed to predict the slope k and data, is the correlation between the summarised in the two multilinear 0.2% C and case-hardened MIM Nk(|k|)NK(k) == 143961 * |k|k - - 411136 Ps=50% 100000000 the cut-off point NK as a function of slope k and the cut-off point NK. If regression terms above, is the 8620). In both cases, the slope k is 5 7.5 100 15 200 25 the sintered density r, loading ratio the positive values of the slopes k are extraordinary behaviour of case- double or triple the other slopes k. |k|k (1)() R and stress concentration factor Kt. plotted with the corresponding cut-off hardened materials. Case-hardened In the presence of higher loading

Fig. 12 Correlation between the cut-off point NK and the slope k, the derived The eight datasets mentioned above, points NK, a progressive tendency can PM steels exhibit very flat Wöhler ratios R and/or higher stress

diagram exhibits a significant similarity to results from [23, 24]. The component and some extra datasets (incomplete be extracted as shown in Fig. 12. This lines s-N at fully reversed (loading concentration factors Kt, the effect s-N curves, derived on gears (Table 6 [32]), fall onto the same scatter band datasets) were used for the statistical diagram is in very good accordance ratio R=-1) and unnotched (stress disappears [24].

sintered density of r=7.0 g/cm³ varies transfers predefined components 1200 120000000000 significantly from the other achieved for a focused evaluation. Material 1100 110000000000 FLD-49HP + 0.65 % C, sintered densities r. Similarly values do not have to be picked twice Radevormwald 963, ϑ=1120 °C, t=23 min, 1000 1000000000000 untransparent behaviour is found for and can possibly even be from two ∆ϑ ∆ / t800 °C-600 °C=-44 °C/min (0 % cooling), 900 00000 slope k. However, since there is no different data sources. 900000 95 % N + 5 % H + 200 l/h CH , 2 2 4 better possibility, the cut-off points Such an interface avoids duplica- 800 80000000000 bending loading, K =1.04, R=-1/0/0.5 t N and slopes k are linearly inter- and tion of work, and, in particular, 700 70000000000 K extrapolated with the equations given it avoids errors and makes an 600 ( ) (1)

00000 (MPa) K 600000

in Figs. 13 and 14. important contribution to simulation σ

N 500 N 50000000000 Additionally, the stress-strain s-e data management. If, for example, 400 40000000000 curves are synthesised as described in the stress s calculation becomes FLD-49HP + 0.65 % C, 300 Radevormwald 963, ϑ=1120°C, t=23 min, 30000000000 [37]. Fig. 15 shows synthesised stress- invalid due to a change, this also 200 Δ ϑ/Δt800°C-600°C=-44°C/min (0% cooling), strain s-e curves of the used material. becomes permanently linked to the 95% N + 5% H + 200 l/h CH , 20000000000 100 2 2 4 The reasons for this procedure are: fatigue life N calculation. Here, Ansys 10000000000 N =-1815260+307843 cm³/g*ρ K Mechanical is used in the Ansys 0 • Stress-strain σ-ε curves are 0.000 0.005 0.010 0.015 0.020 0.025 0.030 0 Workbench environment for the 6.7 6.8 6.9 7.00 7.1 7.2 7.3 needed for the static strength (1) structural mechanical calculation ε 3 assessment in general to approxi- ρρ ((g/cmg/cm³) 3 3 mate the local yielding and the and nCode DesignLife for the fatigue ρ=6.2 g/cm , synthesized ρ=7.0 g/cm , synthesized ρ=6.4 g/cm3, synthesized ρ=7.2 g/cm3, synthesized Fig. 13 Cut-off points NK as function of sintered density r of Ancorsteel FLD- resulting stress rearrangement calculation. With nCode inside Ansys, ρ=6.6 g/cm3, synthesized ρ=7.4 g/cm3, synthesized an interface is available that fully 49HP + 0.65 % C with a sintered density of r=6.8 g/cm³, r=7.0 g/cm³ and r=7.2 (macro support effect). ρ=6.8 g/cm3, synthesized ρ=7.6 g/cm3, synthesized g/cm³ (bending loading mode, survival probability: P =50%) integrates nCode DesignLife into the s • The ultimate tensile strength σ is u Ansys Workbench project environ- Fig. 15 Synthesized stress-strain s-e curves of Ancorsteel FLD-49HP + 0.65% C needed to cut the corresponding ment. In addition to the fixed link over a wide sintered density r range Haigh damage line in the mean -2- between the stress s and fatigue life stress σ direction (beyond M ). k=-11.840+0.693 cm³/g*ρ m 4 N calculation, the interface can also -3- be used to store specially adapted -4- nCode inside Ansys nCode DesignLife templates in the The definition of the required are shown in Figs. 16 and 17. The -5- Ansys Workbench environment and survival probability Ps and the logarithmic standard deviation of the make them available with identical corresponding total effective loga- strength s can be calculated using -6- The numerical fatigue assessment s in its entirety comprises different settings to all users. rithmic standard deviation stotal=SEIs the u(84%)≈1 quantile as:

( ) -7- approaches and, within these k

k (1) -8- approaches, a large number of FLD-49HP + 0.65 % C, options to be set. An example of such -9- Radevormwald 963, ϑ=1120 °C, t=23 min, ∆ϑ ∆ a selectable option is whether or not / t800 °C-600 °C=-44 °C/min (0 % cooling), -10-0 the local support effect is taken into 95 % N2 + 5 % H2 + 200 l/h CH4, account for the fatigue assessment. -11- bending loading, Kt=1.04, R=-1/0/0.5 If it is to be taken into account, the -12- 6.7 6.8 6.9 7.00 7.1 7.2 7.3 support effect must be determined from the local stress gradient and a ρ ((g/cmg/cm³3) stored relationship. These, as well as Fig. 14 Slopes k as function of sintered density r of Ancorsteel FLD-49HP + all other functionalities necessary for 0.65% C with a sintered density of r=6.8 g/cm³, r=7.0 g/cm³ and r=7.2 g/cm³ the fatigue calculation, are typically

(bending loading mode, survival probability: Ps=50%) made available in special software, such as nCode DesignLife, FEMFAT, fe-safe or WINLIFE, to name just a few. Published component Wöhler validation are constant cut-off points The fatigue life N calculation

lines s-N are rare and, especially, of NK=2000000. However, a few always needs the stress s or strain e the resulting slopes k and cut-off component Wöhler lines s-N are values as the result of the structural

points NK are rarely communicated summarised in Table 6. mechanical FEA-calculation. These since the derivation of the fatigue Figs. 13 and 14 show the density data are contained in the results file

strength at the knee point sA was dependency of the investigated from the FEA-calculation and must of higher interest and importance. Ancorsteel FLD-49 HP + 0.65% C be read into the fatigue calcula- Unfortunately, the recording material. In this case, the cut-off tion. It is advantageous to install a

quality and the statistical valida- points NK increase with an increasing functional interface between the two Fig. 16 Definition of the required survival probability Ps in nCode inside Ansys (here a survival probability of Ps=97.5%, tion of many published values is sintered density r. However, there software products, which firmly links according to the FKM guideline [11], was chosen). Together with the total effective logarithmic standard deviation

insufficient [25, 26, 27, 28]. One is no general trend in terms of the the FEA-result file with the fatigue stotal=SEIs=0.0325, the material and the manufacturing scatter contributions are incorporated. Moreover, the DesignLife

relic of this insufficient statistical sintered density r. The intermediate life N analysis and, if necessary, also Configuration Editor defines the used mean stress sm correction model and the used stress gradient c* correction model

74 Powder Metallurgy Review Spring 2021 © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd Spring 2021 Powder Metallurgy Review 75 = 84% Managing PM fatigue data | contents | news | advertisers | events | website= | e-newsletter | | contents | news | advertisers | events | website | e-newsletter | Managing PM fatigue data 𝐴𝐴𝐴𝐴 𝑓𝑓𝑓𝑓 = 50% 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 �𝑃𝑃𝑃𝑃 � = 84% 𝑐𝑐𝑐𝑐 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑏𝑏𝑏𝑏 � 𝐴𝐴𝐴𝐴 𝑓𝑓𝑓𝑓 � = 𝜎𝜎𝜎𝜎 �𝑃𝑃𝑃𝑃 � = 50% 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴�𝑃𝑃𝑃𝑃𝑓𝑓𝑓𝑓 � 𝑐𝑐𝑐𝑐𝜎𝜎𝜎𝜎 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑏𝑏𝑏𝑏 � � 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴�As𝑃𝑃𝑃𝑃𝑓𝑓𝑓𝑓 a consequence,� the derived • Goodman→linear Haigh damage values of the logarithmic standard line deviation of the strength ss and of the • Gerber→parabolic Haigh manufacturing sM should be super- damage line imposed because the probability of • Interpolate→interpolates occurrence of both maximum values between different Wöhler lines is unlikely. The Gaussian error propa- s-N (different loading ratios R gation law assumes a geometric needed) addition of all errors (standard devia- • FKM→defines the Haigh damage tions si). That convolution leads to the total effective logarithmic standard line in four regimes

deviation stotal as: • Goodman, tension only→as above, but with a constant mean = = + = 2 × 0.023 = 0.0325 stress sensitivity M for compres- 2 2 2 sive loading ratios R< -1 𝑆𝑆𝑆𝑆𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑚𝑚𝑚𝑚𝑡𝑡𝑡𝑡 �𝑐𝑐𝑐𝑐𝜎𝜎𝜎𝜎 𝑐𝑐𝑐𝑐𝑀𝑀𝑀𝑀 � • Gerber, tension only→as above, = = + = 2 × 0.023 = 0.0325 Fig. 18 Dialogue window for the input of the mean stress sensitivities M1, M2, but with a constant mean stress 2 2 2 M3 and M4 according to the FKM guideline (here for Fe + 1.75% Ni + 1.5% Cu + 𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑚𝑚𝑚𝑚𝑡𝑡𝑡𝑡 𝜎𝜎𝜎𝜎 𝑀𝑀𝑀𝑀 𝑆𝑆𝑆𝑆𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐 �𝑐𝑐𝑐𝑐 𝑐𝑐𝑐𝑐 � sensitivity M for compressive 0.5% Mo + 0.5% C (Distaloy AB/Höganäs AB or FD-4600A/Hoeganaes Corpora- This value is set by default in loading ratios R< -1 tion type) with a sintered density of r=6.8 g/cm³). The mean stress sensitivi- ‘nCode inside Ansys’ as shown • Chaboche→an in-house derived ties of M1=M4=0 are recommendations from the FKM guideline [11]. In reality, Equation on page 24: in Fig. 17. The nomenclature is a Equation on page 24: mean stress correction factor b an asymptotic behaviour is more realistic. However, these assumptions save

little different.( This) value( is called) Equation on page 24: = = 50% + × is needed to feed this tempera- testing capacity and led to the decision to test just three loading ratios R (R=-1, standard error of log10(stress) R=0 and R=0.5) for the derivation of the mean stress sensitivities M and M 𝐴𝐴𝐴𝐴 =𝑠𝑠𝑠𝑠84% 𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 ( 𝑆𝑆𝑆𝑆=𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴90𝑆𝑆𝑆𝑆 %) ture-dependent damage model 2 3 SEls in nCode=𝜎𝜎𝜎𝜎 84𝑃𝑃𝑃𝑃 inside% 𝜎𝜎𝜎𝜎 Ansys𝑃𝑃𝑃𝑃 0. 39[15]. By( 𝑒𝑒𝑒𝑒 =𝑐𝑐𝑐𝑐90%) ( ) = ( = 50%) + × 0.39 R-Ratio: -1 𝐴𝐴𝐴𝐴 𝑓𝑓𝑓𝑓 = 50% 𝐴𝐴𝐴𝐴( 𝑓𝑓𝑓𝑓 = 10%) = 84% integration( 𝐴𝐴𝐴𝐴 =𝑓𝑓𝑓𝑓 90= of%50 the)% required survival𝐴𝐴𝐴𝐴( 𝑓𝑓𝑓𝑓 = 10%) The chosen FKM method requires the 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎 �𝑃𝑃𝑃𝑃 � 𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 0.39𝜎𝜎𝜎𝜎 𝑠𝑠𝑠𝑠 ≈ 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝜎𝜎𝜎𝜎 ��𝑃𝑃𝑃𝑃 � � ≈ 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝜎𝜎𝜎𝜎 �𝑃𝑃𝑃𝑃 � 2.7 𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝑠𝑠𝑠𝑠𝐴𝐴𝐴𝐴 ≈𝑠𝑠𝑠𝑠𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙probability� 𝐴𝐴𝐴𝐴 P𝑓𝑓𝑓𝑓s all𝑆𝑆𝑆𝑆𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 strength𝑆𝑆𝑆𝑆� ≈ values𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 � are 𝐴𝐴𝐴𝐴 𝑓𝑓𝑓𝑓 � input of the mean stress sensitivities 𝐴𝐴𝐴𝐴 𝑓𝑓𝑓𝑓 = 50%𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 𝐴𝐴𝐴𝐴( 𝐴𝐴𝐴𝐴𝑓𝑓𝑓𝑓 𝜎𝜎𝜎𝜎=𝑓𝑓𝑓𝑓�𝑒𝑒𝑒𝑒10𝑃𝑃𝑃𝑃 %𝑐𝑐𝑐𝑐) � 𝐴𝐴𝐴𝐴 𝜎𝜎𝜎𝜎𝑓𝑓𝑓𝑓 𝑃𝑃𝑃𝑃 𝜎𝜎𝜎𝜎 � 𝑃𝑃𝑃𝑃 � converted𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎𝑃𝑃𝑃𝑃�𝑃𝑃𝑃𝑃 with the� Gaussian quantile𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 𝜎𝜎𝜎𝜎 M1, M2, M3 and M4 [5] as shown in 𝑠𝑠𝑠𝑠 ≈ 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 � 𝐴𝐴𝐴𝐴And𝑓𝑓𝑓𝑓 then � ≈ 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 � 𝐴𝐴𝐴𝐴 𝑓𝑓𝑓𝑓 �

) [MPa] 2.6 And then 𝜎𝜎𝜎𝜎 �𝑃𝑃𝑃𝑃 � u𝜎𝜎𝜎𝜎 as:𝑃𝑃𝑃𝑃 Fig. 18. They are defined in intervals 10 And then as [11, 15]: 2.5 ( ) = ( = 50%) + × ( ) = ( = 50%) + × • M when R >1 1→ 2.4 𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝑆𝑆𝑆𝑆𝐴𝐴𝐴𝐴𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 ( ) = ( = 50%) + × 𝐴𝐴𝐴𝐴 𝜎𝜎𝜎𝜎𝑠𝑠𝑠𝑠 𝑃𝑃𝑃𝑃 𝐴𝐴𝐴𝐴 𝜎𝜎𝜎𝜎𝑠𝑠𝑠𝑠 𝑃𝑃𝑃𝑃 𝑢𝑢𝑢𝑢 𝑆𝑆𝑆𝑆𝐴𝐴𝐴𝐴𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑠𝑠𝑠𝑠 Or Or or𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 𝑢𝑢𝑢𝑢 𝑠𝑠𝑠𝑠 • M2→when -∞ ≤ R< 0

𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝑆𝑆𝑆𝑆𝐴𝐴𝐴𝐴𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 • M when 0 ≤ R< 0.5 2.3 Or 𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 𝑢𝑢𝑢𝑢 𝑠𝑠𝑠𝑠log ( ( )) = log ( ( = 50%)) + × 3→ log ( ( )) = log ( ( = 50%)) + × • M4→when 0.5 ≤ R< 1 2.2 log ( ( )) = log ( ( = 50%)) + ×𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝜎𝜎𝜎𝜎 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝜎𝜎𝜎𝜎𝑃𝑃𝑃𝑃𝑠𝑠𝑠𝑠 𝑃𝑃𝑃𝑃 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝜎𝜎𝜎𝜎𝑃𝑃𝑃𝑃𝑠𝑠𝑠𝑠 𝑃𝑃𝑃𝑃 𝑢𝑢𝑢𝑢 𝑢𝑢𝑢𝑢𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎 𝑠𝑠𝑠𝑠

Alternating stress (Log stress Alternating Three different options are possible 𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝜎𝜎𝜎𝜎 2.1 𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 In 𝑢𝑢𝑢𝑢these𝑠𝑠𝑠𝑠 equations the parameters for the stress gradient c* correction are coded as follows: model [15]: 2 P : Failure probability 0 1 2 3 4 5 6 7 8 9 f • Auto→stress gradient c* correc- Ps: Survival probability tion according to FKM guideline Cycles (Log10) sSAFD: Standard deviation • User stress gradient c* correc- Fig. 17 Definition of the total effective logarithmic standard deviation → according to SAFD software tion according to an in-house stotal=SEIs=0.0325, the material and the manufacturing scatter contributions are derived look-up table incorporated (here for Fe + 1.75% Ni + 1.5% Cu + 0.5% Mo + 0.5% C (Distaloy ss: Logarithmic standard devia- AB/Höganäs AB or FD-4600A/Hoeganaes Corporation type) with a sintered tion of the strength • Off→no stress gradient c* density of r=6.8 g/cm³) sM: Logarithmic standard devia- correction tion of the manufacturing Equation on page 24: As depicted in Fig. 16, the support

stotal: Total effective logarithmic effect of sintered PM steels is standard deviation Equation on page 24: = 84% rithmic( = 90 standard%) deviation of the covered by the equation presented 0.39 SEls: Standard error of above as User. The equation must = 50% strength( = 10% ss) was investigated for 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴�𝑃𝑃𝑃𝑃𝑓𝑓𝑓𝑓 � 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑃𝑃𝑃𝑃𝑓𝑓𝑓𝑓 log10(stress) 𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎 ≈ 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 � � ≈ 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 � sintered PM� steels in [14]. However, be introduced as tabulated relative = 84% 𝐴𝐴𝐴𝐴 ( 𝑓𝑓𝑓𝑓 = 90%) 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑃𝑃𝑃𝑃𝑓𝑓𝑓𝑓 0.39 𝜎𝜎𝜎𝜎 �𝑃𝑃𝑃𝑃 � small manufacturing errors should u: Gaussian quantile stress gradient c* and support factor ( = 10%) And then𝐴𝐴𝐴𝐴 𝑓𝑓𝑓𝑓 = 50% 𝐴𝐴𝐴𝐴 𝑓𝑓𝑓𝑓 𝜎𝜎𝜎𝜎 �𝑃𝑃𝑃𝑃 � 𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 be incorporated. Under high- nc data pairs, as shown in Fig. 19. 𝜎𝜎𝜎𝜎 nCode inside Ansys supports eight 𝑠𝑠𝑠𝑠 ≈ 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 � 𝐴𝐴𝐴𝐴 𝑓𝑓𝑓𝑓 � ≈ 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 � 𝐴𝐴𝐴𝐴 𝑓𝑓𝑓𝑓 � 𝜎𝜎𝜎𝜎 �𝑃𝑃𝑃𝑃 � For the approximation𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 of each quality production conditions, the A few calculation jobs on gears mean stress sm correction models And then required survival probability P , a logarithmic standard deviation of are helpful to understand the power ( ) = ( = 50s %) + × [15]:

combined logarithmic standard the manufacturing sM will exhibit a of the generated database and its Or 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑃𝑃𝑃𝑃𝑠𝑠𝑠𝑠 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑃𝑃𝑃𝑃𝑠𝑠𝑠𝑠 𝑢𝑢𝑢𝑢 𝑠𝑠𝑠𝑠𝑆𝑆𝑆𝑆𝐴𝐴𝐴𝐴𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 deviation is chosen as input for similar magnitude to the material • None→no mean stress sm underlying assumptions. By drag Fig. 19 Tabulated relative stress gradient c* and support factor nc data pairs ( ) = ( = 50%) + × correction and drop, the required material and ‘nCode insidelog ( Ansys’.( )) = Thelog ( loga( -= 50%)) +scatter× [14]. according [10] for nCode inside Ansys 𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝐴𝐴𝐴𝐴 𝑠𝑠𝑠𝑠 𝑆𝑆𝑆𝑆𝐴𝐴𝐴𝐴𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 Or 𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 𝜎𝜎𝜎𝜎 𝑃𝑃𝑃𝑃 𝑢𝑢𝑢𝑢 𝑠𝑠𝑠𝑠 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑃𝑃𝑃𝑃𝑠𝑠𝑠𝑠 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑃𝑃𝑃𝑃𝑠𝑠𝑠𝑠 𝑢𝑢𝑢𝑢 𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎 log ( ( )) = log ( ( = 50%)) + × 76 Powder Metallurgy Review Spring 2021 © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd Spring 2021 Powder Metallurgy Review 77 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑃𝑃𝑃𝑃𝑠𝑠𝑠𝑠 𝜎𝜎𝜎𝜎𝐴𝐴𝐴𝐴 𝑃𝑃𝑃𝑃𝑠𝑠𝑠𝑠 𝑢𝑢𝑢𝑢 𝑠𝑠𝑠𝑠𝜎𝜎𝜎𝜎 Managing PM fatigue data | contents | news | advertisers | events | website | e-newsletter | | contents | news | advertisers | events | website | e-newsletter | Managing PM fatigue data

Life (Repeats) Life (Repeats)

No Data No Data Beyond Cutoff Beyond Cutoff 3.535e+08 2.764e+08 1.264e+08 9.198e+07 4.660e+07 3.060e+07 1.692e+07 1.018e+07 6.143e+06 3.388e+06 2.230e+06 1.127e+06 8.098e+05 3.751e+05 2.940e+05 1.248e+05 1.068e+05 4.153e+05 3.876e+04 1.382e+04

Max = Beyond cutoff Min = 3.876E4 Max = Beyond cutoff Min = 1.382E4 at node 436205 at node 336864 at node 436193 at node 336864

Fig. 20 The fatigue life of this gear is calculated as N=38800 (loading ratio R=0.05, survival probability Ps=50%, without Fig. 22 The fatigue life of this gear is calculated as N=13800 (loading ratio R=0.05, survival probability Ps=97.5%, without

support effect [nc >1]) support effect [nc >1])

Life (Repeats) Life (Repeats)

No Data No Data Beyond Cutoff Beyond Cutoff 4.276e+08 3.815e+08 1.881e+08 1.516e+08 8.277e+07 6.022e+07 3.642e+07 2.393e+07 1.602e+07 9.508e+06 7.049e+06 3.778e+06 3.101e+06 1.501e+05 1.364e+06 5.964e+05 6.003e+05 2.370e+05 2.641e+05 9.416e+04

Max = Beyond cutoff Min = 2.641E5 Max = Beyond cutoff Min = 9.416E4 at node 436253 at node 336865 at node 436253 at node 336865

Fig. 21 The fatigue life of this gear is calculated as N=264000 (loading ratio R=0.05, survival probability Ps=50%, with Fig. 23 The fatigue life of this gear is calculated as N=94100 (loading ratio R=0.05, survival probability Ps=97.5%, with

support effect [nc >1]) support effect [nc >1])

sintered density r can be chosen. of the individual CAE-engineer. the CAE-engineers, as well been generated to feed the fatigue density-dependent approximation studies are possible to exhibit Figs. 20–23 show a quick parameter This is a significant advantage as other internal and external software. For the reduction of the of the material properties and the best material-density-heat study on how the support effect in a globalised community if the customers (sales, etc), with data. huge testing effort, a few simplifica- model parameters using Balshin’s treatment combination to combine

and the survival probability Ps organisation operates different A clear interface was needed to tions have been adopted from the power-law. As a result, every a reliable product design with an affect the resulting fatigue life N facilities (plants). read the FEA results, the stresses literature. sintered density r is treated as an attractive price. This is what we call of Ancorsteel FLD-49HP + 0.65% s and the strains e, into an FEA The fatigue testing was harmonised independent material dataset. ’design for X’. C with a sintered density of r=7.0 post-processor. The fatigue with the required material properties A to B material comparisons The GKN Sinter Metals PM g/cm³. Similar parameter studies Summary and conclusions software nCode was chosen as and model parameters requested by were unilateral in the past, fatigue database currently consists can be performed by the varia- the FEA post-processor for our nCode. Generally, the FKM method is because just a single material of twelve commonly-used sintered tion of the material and/or of the The development of the GKN Sinter structural Ansys Mechanical FEA included in all commercially available property, e.g. the ultimate tensile PM steels, two sintered MIM

sintered density r. This approach Metals PM fatigue database became software, leading to nCode inside fatigue software packages. Therefore, strength su, was compared. steels, two AM steels and one AM is helpful with regard to finding the necessary due to increased requests Ansys. Since sintered PM steels a FKM-conforming fatigue testing However, a fatigue assessment aluminium alloy. Further datasets best (cheapest) material-density- in terms of material properties are not included in the common programme will also satisfy the provokes the interaction of are planned, but with the impor- heat treatment combination. The and requested static and cyclic fatigue databases and other requests from the fatigue software. several parameters and gives tance shifting to materials used database approach guarantees (fatigue) strength assessments. A good, complete – and, for nCode, Modifications are needed for a proper a better overview regarding the more in Additive Manufacturing consistent material properties and storage system and a consistent readable – datasets do not exist, approximation of the behaviour of performance of a special material. (steels, aluminium alloys and model parameters independent database were needed to support our own in-house datasets have sintered PM steels. A key role is the From now, very quick parameter plastics).

Authors [7] J Schijve: Fatigue of Structures FEMFAT), DVM – Betriebsfestigkeit gesinterte Bauteile’, Bericht Nr. [34] A Zafari, K Lipp, P [37] M Schneider, ‘Density Dependent and Materials, Springer, 2nd edition, ‘Bauteillebensdauer: Rechnung und FB-170, Fraunhofer-Institut für Beiss, Abschlussbericht des Approximation Of Stress-Strain Dr Markus Schneider, Robert 2009 Versuch’ 19. Vortragsveranstaltung Betriebsfestigkeit Darmstadt, Forschungsprojektes ‘Einfluss Curves For Elastic-Plastic des DVM-Arbeitskreises Darmstadt, 1984 äußerer Kerben auf die FEA-Calculations’, Proc. Euro PM Maassen, Dennis Wawoczny and [8] D Radaj, M Vormwald, Betriebsfestigkeit, DVM, Berlin, 1993 Schwingfestigkeit von Sinterstahl’, 2019 Maastricht, Proc. USB, No. Christos Radis Ermüdungsfestigkeit, Springer, [29] Personal communication Robert AVIF-Nr. A 253, Stiftung 4349131; EPMA, Shrewsbury, UK, Berlin, Heidelberg, 3nd edition, 2007 [20] W Eichlseder, ‘Rechnerische Maassen (internal investigation of Stahlanwendungsforschung, 2019 GKN Sinter Metals Lebensdaueranalyse von GKN Sinter Metals) [9] T Nicholas, High Cycle Fatigue, Düsseldorf, 2011 Engineering GmbH Nutzfahrzeugkomponenten mit der Elsevier, Amsterdam, Boston, [30] Personal communication Radevormwald FE-Methode’, Dr-Ing Thesis, TU Heidelberg, London, New York, Christos Radis (internal investigation [35] P Beiss, S Keusemann, K Lipp, Germany Graz, 1989 of GKN Sinter Metals) J Baumgartner, Abschlussbericht www.gknpm.com Oxford, Paris, San Diego, San Francisco, Singapore, Sydney, Tokyo, [21] M Wächter, C Müller, A Esderts, des Forschungsprojektes ‘Neue [email protected] [31] Personal communication st Angewandter Festigkeitsnachweis universelle Bemessungsmethode 1 edition, 2006 Thomas Schupp (internal investiga- nach FKM-Richtlinie, Springer für schwingend belastete gesinterte [10] S Sähn, H Göldner, Bruch- tion of GKN Sinter Metals) Appendix Vieweg, Wiesbaden, 1st edition, 2017 Bauteile komplexer Geometrie’, AVIF- und Beurteilungskriterien in der [32] Personal communication Robert Nr. A 270, Stiftung Stahlanwendung, [22] E Haibach, Betriebsfestigkeit, Festigkeitslehre, VEB Fachbuchverlag Maassen (internal investigation of Düsseldorf, 2014 An appendix to this article containing st VDI Verlag, Düsseldorf, 1st edition, Leipzig, 1 edition, 1989 GKN Sinter Metals) further valuable raw data (Wöhler 1989 [36] Herausgeber, O Buxbaum, lines s-N) is available to download [11] S Keusemann, ‘Ermüdung von [33] J Baumgartner, E Haberlick, Vorträge des vierten [23] M Hück, L Thrainer, W Schütz, via the url below: Sinterstählen in Abhängigkeit vom K Lipp, ‘Fatigue Assessment of LBF-Kolloquiums am 31 Januar und Berechnung von Wöhlerlinien hochbeanspruchten Volumen und Hardened PM Steel Components’, 1 Februar 1984 in Darmstadt, Bericht bit.ly/PMappendix für Bauteile aus Stahl, Stahlguß Spannungsverhältnis’, Dr-Ing Thesis, Proc. Euro PM 2020 Lisbon, Proc. Nr. TB-171, Fraunhofer-Institut und Grauguß – Synthetische RWTH Aachen, 2014 USB, No.; EPMA, Shrewsbury, UK, für Betriebsfestigkeit Darmstadt, Wöhlerlinien, 3nd edition, Report ABF 2020 Darmstadt, 1984 References [12] Y Murakami, Metal Fatigue: 11, 1983 Effects of Small Defects and [24] M Schneider, ‘High-cycle fatigue [1] R Steiner: Grundkurs Relationale Nonmetallic Inclusions, Elsevier, st response of MIM 8620 and 100Cr6 Datenbanken, Einführung in die Amsterdam, 1 edition, 2002 steels and their sensitivity to mean Praxis der Datenbankentwicklung für [13] P Beiss, ‘Stress controlled stress, notch sharpness and weld Ausbildung, Studium und IT-Beruf, fatigue testing of porous sintered line position’, PIM International, Vol. Springer, Berlin Heidelberg, New steels – an endless task’, Advances st 14, No. 3, 2020, pp. 75-91 York, 1 edition, 2014 in Powder Metallurgy & Particulate [25] C M Sonsino, ‘Fatigue Design [2] Personal communication Materials, Metal Powder Federation, Princeton, NJ, 2008, Vol. 4, pp. 60-83 of Sintered Con-Rods’, Report Professor Paul Beiss No. FB-190, Fraunhofer-Institut [14] M Schneider, ‘A Safety Factor [3] H I Sanderow, The Global für Betriebsfestigkeit Darmstadt, For Sintered PM Components’, Proc. Powder Metallurgy Database; SAE Darmstadt, 1990 Euro PM 2018 Bilbao, Proc. USB, No. International, 2005 3984306; EPMA, Shrewsbury, UK, [26] C M Sonsino, K Lipp, ‘Improvement of fatigue properties [4] M Schneider, V A Savu, ‘The 2018 of sintered con-rods by adequate Support Effect and its Impact on the [15] DesignLife Theory Guide, HBM selection of material, density Design of Complex Shaped Sintered United Kingdom Limited, 2013 and heat treatment’, Final report PM Parts’, International Journal of COST 503/II, Fraunhofer-Institut Powder Metallurgy, Vol. 55, No. 4 [16] FEMFAT Seminar Notes, Magna für Betriebsfestigkeit Darmstadt, (2019), pp. 11–22 Powertrain, St. Valentin, 2013 Darmstadt, 1993 [17] H Gudehus, H Zenner, Leitfaden [5] R Rennert, E Kullig, M [27] C M Sonsino, ‘Einfluß für eine Betriebsfestigkeitsrechnung, Vormwald, A Esderts, D Siegele, sintertechnischer Grenzen auf Verlag Stahleisen, Düsseldorf, 4th Rechnerischer Festigkeitsnachweis die Herstellung von schwing- edition, 2007 für Maschinenbauteile, VDMA Verlag, beanspruchten Bauteilen Frankfurt am Main, 6th edition, 2012 [18] O Buxbaum, Betriebsfestigkeit, aus Sinterstahl’, Bericht Nr. Verlag Stahleisen, Düsseldorf, 2nd FB-184, Fraunhofer-Institut für [6] R I Stephens, A Fatemi, R R edition, 1992 Betriebsfestigkeit Darmstadt, Stephens, H O Fuchs: Metal Fatigue Claim your discounted fee by Darmstadt, 1989 On-line Learning: April - July 2021 in Engineering, John Wiley & [19] B Unger, W Eichlseder, F * Storage and Discharge of Powders and Bulk Materials; referring to this advert. Sons, Inc., New York, Chichester, Schuch, Lebensdauerberechnung [28] C M Sonsino, ‘Schwingfestigkeit * Caking and Lump Formation in Powders and Bulk Solids; [email protected] Weinheim, Brisbane, Singapore, Auf Basis Von Finite Elemente von verschiedenen Sinterstählen * Powder Handling and Flow for Additive Manufacturing; 020 8331 8646 Toronto, 2nd edition, 2001 Ergebnissen (Fe-Postprozessor und Bemessungskriterien für

PM CHINA 2021 Reducing CO2 emissions in the The 14th Shanghai International Powder Metallurgy Exhibition & Conference PM industry: A lifecycle analysis May 23-25, 2021 of servo-electric versus Shanghai World Expo Exhibition Center hydraulic powder presses

There is a global need for action to minimise greenhouse gas emissions and, thus, limit further global warming. Despite its reputation as a technology which is already greener than most, this also holds true in the Powder Metallurgy industry. In recent years, PM companies have found themselves under increasing pressure to improve process sustainability, from their customers as well as regulators. This pressure is only likely to increase in the near future. Michael Looser and Michael Sollberger, of Switzerland’s Osterwalder AG, explain how the company’s servo-electric powder presses help make PM even more efficient.

The pressing of metal powder and presses with 2000 kN compacting The lifecycle in the case study is as subsequent sintering is already a very force were compared over the service follows: The powder press is produced energy efficient method of producing life of a typical press: twenty-five in Switzerland, then transported to metal parts. Nevertheless, there is years. Fig. 1 shows the Osterwalder Asia. It is operated, maintained and room for improvement. The use of OPP 2000 servo-electric press used finally dismantled and disposed of in servo-electric powder presses is one in this comparison. Asia. An illustration of the lifecycle of area where Powder Metallurgy could become even more efficient. Today, the majority of powder presses available on the market are Convergence of equipped with mechanical, hydraulic or servo-electric drive systems. However, most of the currently oper- Cutting-edge Technology & Products ational presses in the industry are CNC-controlled fully hydraulic units. In this article, conventional hydraulic powder presses are compared with a new generation of servo-electric powder presses, with a specific focus on their environmental impact. A case study in the form of a Organizer lifecycle assessment (LCA) was carried out, showing in which lifecycle phases servo-electric powder presses are more efficient Tel: +86 4000 778 909 +86 20 8327 6369/6389 than hydraulic presses, and in which Fig. 1 Osterwalder’s new OPP 2000, a 2000 kN servo-electric multi-platen the opposite is true. Servo-electric powder press, was compared against an equivalent hydraulic powder press in Email: [email protected] [email protected] and hydraulic multi-platen powder this study Web: www.pmexchina.com

Raw Material T life that the greatest potential exists to Comparison of the processes (logarithmic scale) RA Extraction NS minimise greenhouse gas emissions. PO 1000 R TA In the life stages of production, T 290.5 Hydraulic End of life IO transport and disposal, emissions are N only caused once, not every year. For Servo-electric 89.4 Material a better comparison with the other 100 N O Processing I stages, the emissions of the above- T

T T mentioned life stages are distributed

R R

A O through all operating years (X t CO2-eq

N P

-eq/a S S

/ lifecycle). 2 10

N O

A 4.0 R 3.7

R 3.4

t CO

T T

T I

O Manufacturing the press 1.2

N Product 0.8

1 0.6 Use

Part In the press production process,

0.21

Manufacturing greenhouse gas emissions are mainly

T 0.16 N

I A

N generated in steel production and

T P

R 0 O

R transport, hydraulic oil production

T Production Transport Operation Maintenance Disposal

I A

N T

and the manufacturing of electric motors (especially in servo-electric Fig. 3 Greenhouse gas emissions per lifecycle stage for hydraulic and servo-electric powder presses Assembly powder presses). Despite the poor eco-balance of the servomotors and Fig. 2 The lifecycle of a product, from production to disposal the power electronics installed, less greenhouse gases are emitted in the tation emits less greenhouse gases. a servo-electric powder press. It Press maintenance a product is shown in Fig. 2; an over- Lifecycle analysis manufacturing of a servo-electric About 4.4 t CO2-eq are saved (once, should be noted that emissions view of the factors considered at each system than of a hydraulic powder not per operating year). The trans- savings strongly depend on the stage of the lifecycle of a powder In the following sections, the press. port route and means of transport electricity mix in the country in In the maintenance of a press, green- press is shown in Table 1. In this results of the LCA are compared Expressed in numbers, this is a are the same for both the hydraulic which a press is installed: China, for house gas emissions are generated primarily in the manufacturing LCA, the equivalent tonnes of carbon first within the life stages, then saving of 7.5 t CO2-eq (once during and servo-electric presses. example, still has a high proportion of spare parts and, for hydraulic dioxide per annum (t CO2-eq/a) is as a whole. Fig. 3 shows the the press’s lifecycle, not per operating of coal power in its electricity mix, defined as a functional unit – thus, greenhouse gas emissions per year). One reason for this is that the which leads to higher emissions presses, hydraulic oil production. the greenhouse gases emitted per lifecycle and drive system in the servo-electric powder press is lighter Industrial operation in power production and, thus, in The greenhouse gas emissions operating year are determined, with functional unit. The amount of in weight, since various components, power consumption. However, this generated in the transportation of spare parts and oil to the customer CO2-eq (CO2 equivalents) being a unit CO2-eq emitted per year is shown such as the hydraulic unit and the Greenhouse gas emissions during does not have an effect on the elec- that describes the global warming above the bar. hydraulic accumulators, can be the operational life of the press are tricity saved by the servo-electric and recycling or disposal of the potential of a gas. For example, Listed are the greenhouse gas eliminated. As a result, emissions are primarily the result of the energy drive concept, which significantly discarded material are relatively

the combustion of fuels produces emissions in t CO2-eq/a broken reduced during raw material extrac- required to run it. The servo-electric reduces operating costs. minor. Since a servo-electric press not only carbon dioxide, but other down by stage of life. The operation, steel production and material powder press consumes almost greenhouse gases, such as nitrous tional stage is, by far, the most transport to the production facility at 70% less power in production mode oxide. The emissions of these gases important source of greenhouse the manufacturing site. and almost 80% less energy in

are converted into equivalents of CO2 gases (note the logarithmic Another important factor is the standby than the hydraulic press. and taken into account. Y-axis). It is during this phase of elimination of hydraulic oil, which These energy savings are due to is not required in the production of the elimination of energy-intensive servo-electric drives. In addition, the hydraulic components, in particular Lifecycle stage Includes energy required for assembling servo- the upper punch and die drive. The Extraction, processing and transport of raw materials electric machines is lower, as the servo-electric system also requires Production (e.g. steel, hydraulic oil, magnets), energy consumption reduced variety of parts reduces the less cooling water, since the power during production, commissioning overall assembly time. is primarily delivered by the upper punch and die drives. The cooling Transport by truck and by sea from Switzerland to Transport capacity provided by the plant is not customer in Shanghai Transportation of the press considered in this study because it is Energy consumption for the powder press and internal Operation site-specific and, therefore, difficult cooling water circuit The process of transporting the press to quantify. Preparation, delivery and replacement of spare parts, from Switzerland to China emits The lower energy consumption Maintenance maintenance work greenhouse gases. The amount is reflected in the CO2-eq emissions Disposal Transport, energy and resource expenditure depends on the weight of the press, during operation. Thus, 201.1 t the transport route and the means of CO2-eq ( just under 70%) emissions Table 1 Overview of factors considered at each stage of a powder press’s are saved annually through lower transport. Due to the lower weight of Fig. 4 Another servo-electric press produced by Osterwalder, the SP 320, at lifecycle energy consumption≙ when using the servo-electric press, its transpor- Osterwalder’s press production facility in Switzerland

As was demonstrated earlier in this article, the most 100% greenhouse gas emission-intensive phase of a powder press is its operation. In percentage terms, the greatest 80% potential for savings is also in operation and maintenance 60% 201.1 2.8 of the press, as was shown in Fig. 3. The servo-electric 290.5 4.0 powder press performs only marginally better in the 40% lifecycle stages of production, transportation and disman- 20% tling, where the emissions generated are comparatively 89.4 1.2 insignificant. 0% Operation Maintenance Conclusion [t CO2-eq/a] [t CO2-eq/a] hydraulic servo-electric Savings It is precisely at the two most greenhouse gas emission- intensive stages in the lifecycle of a powder press that Fig. 5 Greenhouse gas emissions for operation and maintenance in t CO2-eq/a are shown in grey and black, while the greenhouse gas emissions saved per year are shown in green Osterwalder has focused its efforts on the reduction of THE MAGAZINE CO2-eq emissions in the Powder Metallurgy industry, through the development of its servo-electrically operated FOR MIM, CIM AND multi-platen powder presses. As has been demonstrated in this study, the servo- requires no hydraulic oil and fewer emitted during the process of disas- End of life disposal electric drive system results in fewer greenhouse SINTER-BASED AM spare parts, annual savings of around sembly; however, the dismantling gas emissions over its entire lifecycle than equivalent 2.8 t CO2-eq ( around 70%) are The calculation of CO emissions of a servo-electric powder press 2 hydraulic systems. With servo-electric powder presses, achieved (Fig. 5). This is due to the during powder press dismantling generates 1.2 t CO2-eq less (once, ≙ the Powder Metallurgy industry can be better prepared to WWW.PIM-INTERNATIONAL.COM fact that a servo-electric powder in this case study is based on the not per year of operation) than the face the increasing pressure on sustainability and do its press operates without some of assumption that a powder press dismantling of a hydraulic press. part to reduce the impact and cost of global warming. the components which would need which has reached the end of its This is due to the lower mass of the to be replaced over the operating life will be transported to a material press that has to be transported and lifespan of a hydraulic press, such recovery plant and disassembled into processed. Authors as cylinders and hydraulic hoses. Oil individual parts, using electricity and changes and service work are also fuel in the process. Overall, only a Overall comparison Michael Looser, Bachelor Environmental required less frequently. small amount of greenhouse gas is Engineering, Intern, and Michael Sollberger, Sales & Development Engineer The total annual greenhouse gas emission savings achieved using Osterwalder AG a servo-electric drive system as Lyss, Switzerland opposed to an hydraulic powder [email protected] press amount to 204.5 t CO -eq/a. 2 www.osterwalder.com In relative terms, this means that greenhouse gas emissions are reduced by almost 70%. The quantity of greenhouse gas emissions saved is equivalent to sixteen journeys around the world with a mid-size gasoline car, or 2,840 iPhone 11 lifecycles. Servo-electric powder presses not only provide an environmental advantage, but also economic benefits. Due to the power savings offered, around $19,000 is saved annually in electricity costs (based on installation in China). Further potential for savings is offered by the trade with emission certificates. The price per

ton of CO2-eq is expected to rise to CN¥116 in China by 2030 (≈ €14).

For comparison: CO2 certificates are

traded in the EU for €25/t CO2-eq (as Fig. 6 Osterwalder employees perform maintenance on a powder press of August 2020).

Nickel-free steel powders: Paving the way for sustainable Powder Metallurgy

Few sectors of industry remain untouched by the demands of sustainability. The response to climate change has ramped up considerably in most countries, with consumers and regulators alike looking for greater assurance that products have the lowest environmental impact possible across the value chain. PM is no exception, and increasing numbers of PM projects on sustainability have emerged to meet this need. The EU’s NEWMAN project is one such effort, seeking to drastically improve PM’s economic and environmental sustainability by minimising nickel content in steel powders. Here, the NEWMAN partners discuss the project’s goals, progress and roadmap to completion.

In recent years, climate change has use of resources. The widely accepted 2°C, preferably 1.5°C, comparable become a major driver for develop- definition of sustainability refers to to pre-industrial levels. Today, ments in technology and material the concept of the ‘Triple Bottom industry is responsible for 35% science. The traditional develop- Line’ (Fig. 1) – that is, the synergistic of all greenhouse gas emissions ment approach, based on the study and systematic relationship between due to energy consumption and of factors such as mechanical three fundamental aspects in devel- industrial processes [3] and many and chemical performance only, opment; the societal, environmental companies are facing challenges in has demonstrated its limits. Many and economic impact of a technology. achieving sustainability via carbon materials have a strong environ- This is also known as 3P: people, neutral production under the new mental impact throughout their planet and profit [2]. EU Green Deal. Consequently, when lifecycle, which can pose a challenge The Paris Agreement attempts to choosing suppliers, the sustainability in improving their recyclability or limit global warming to well below of their products and processes will reusability. In the development of new materials, a holistic approach that includes an analysis of environmental impacts in the research and validation stages is a fundamental principle to achieve sustainability. For instance, the adoption of concepts related to the circular economy during the early research stage may boost the subsequent recovery of available resources and the material’s recyclability [1]. The definition of research strategies that consider elements of sustainability in early stages of development is essential to pursue objectives linked to a more efficient Fig. 1 The Triple Bottom Line: People, planet, profit

2019 Nickel mining/production share Price of nickel ($/ton) no heavy nickel reserves, meaning raw material must be imported from $16.000 Communication non-EU countries, generating a high and dissemination Indonesia Selection of $14.000 environmental impact from transport Ni-free powders Philippines and processing. Due to the political and identification $12.000 Russia instability of some nickel-producing of processes New Caledonia $10.000 countries, the price of nickel is also parameters Canada highly volatile [5]. Reducing the Design of prototype, $8.000 industry’s dependency on nickel for dies and tools Australia Environmental Go to market $6.000 the production of high-performance sustainability China strategy Prototype industrial PM components (such as analysis Brazil production $4.000 gears and gearboxes, sleeves, etc) Cuba Economic Environmental would help to pave the way to a more Prototypes heat $2.000 validation treatment validation Other countries sustainable PM industry. $0 Test on 0% 10% 20% 30% In this context, NEWMAN is 2015 2016 2017 2018 2019 carrying out a series of actions prototypes a) b) to validate the use of nickel-free Performance powders for the production of validation Fig. 2 a) Global mine production share in 2019 and b) the price of nickel from 2015–2019 high-performance PM components and demonstrate the increase in Project management sustainability that can be achieved while maintaining mechanical Fig. 4 The structure of the NEWMAN project performance, by evaluating their be taken into consideration alongside negatively affect sustainability. Thus, tant Professor at the University of economic, mechanical and environ- product quality and price. the environmental impact of PM is Bologna, and his research group, was mental performance. This validation Powder Metallurgy and, in not uniformly low across the entire established with the goal of drasti- is ongoing throughout the project’s Centro Ricerche Fiat (CRF) is an systems. Vici has carried out a feasi- particular press and sinter PM, workflow, but efforts should be made cally reducing the nickel content in duration, with the results shared automotive research centre belonging bility study on how to substitute the already offers environmental advan- to lower it at each stage wherever ferrous alloy metal powders for press continuously among partners, to Stellantis (formerly FCA Group, with traditionally manufactured compo- tages over conventional manufac- possible [4]. and sinter PM. NEWMAN launched creating powerful synergies in order Stellantis having been formed as the nents for nickel-free PM prototypes, turing processes. As a near-net The NEWMAN project (nickel- at the beginning of 2020 and aims to maximise the performance of result of a merger between FCA and whilst modifying the original geom- shape technology, PM production frEe poWders for high-perforMAnce to demonstrate the use of nickel- nickel-free steel powders. Groupe PSA in January 2021). CRF etry. During the second year of the reduces material waste and energy compoNents), initiated and funded free steel powders in an industrial is providing its technical expertise project, Vici will demonstrate the consumption. However, some by the EIT (European Institute of environment by the end of 2021. The to the project to demonstrate the use of these prototypes in its optical processes, such as metal powder Innovation and Technology), a body validation of the nickel-free powders NEWMAN project partners performance of nickel-free powders measuring machines. atomisation and part sintering, can of the European Union, and coordi- developed during the project will in highly-stressed environments. Environmental validation will be increase energy consumption and nated by Alessandro Morri, Assis- take several factors into account: A distinct advantage of NEWMAN CRF has selected a series of conven- undertaken by Ghent University, a the technical performance of the is the inclusion of the whole value tional car components, manufactured Belgian university with a specific powders will be evaluated alongside chain in the project consortium, by traditional casting or PM, and focus on sustainable projects, using the benefits that can be reached at involving partners from all over redesigned them to fulfil the manu- different Life Cycle Assessment the societal (people), environmental Europe. The coordinator is the facturing requirements defined by the (LCA) scenarios to analyse the use of (planet) and economic (profit) levels. Industrial Engineering Department University of Bologna and Sinteris. nickel-free steel powders and identify In recent years, the presence of of the University of Bologna, which is The research centre will test the those with the lowest environmental nickel in steel powders has strongly leading economic and performance prototypes on its test benches, which impact. Finally, CRIT, an Italian inno- affected the sustainability of high- validation, assisted by Sweden’s realistically simulate a car’s behav- vation centre, manages NEWMAN’s performance PM components. Nickel Höganäs AB, developer of the new iour, with the aim of demonstrating project communications, which can have a negative effect on human nickel-free steel powders, which is the mechanical performance of the include supporting the dissemination health: in less serious cases, it can providing various compositions for new nickel-free steel powders. of knowledge and building aware- cause allergic reactions, while for performance testing and qualifi- Vici, an Italian manufacturer of ness of the project’s technological workers exposed to nickel long-term, cation. Sinteris, an Italian metal optical, non-contact shaft measuring advantages among designers and it can be carcinogenic. Environmen- powder sintering company, will machines and quality control systems, end-users. Economic Performance Environmental tally, the mining of nickel is highly define the production and heat treat- wants to exploit the project results to ment process parameters before improve the precision of its machines. validation validation validation damaging; the material’s extraction Project structure and goals is extremely energy intensive and producing prototype parts. The The use of non-traditional manu- water polluting, but 40% of global project also includes two end-users facturing processes, such as PM, nickel reserves are in locations with to demonstrate the performance enables newer and better features in The structure of the project, shown high biodiversity and protected areas, of these prototypes in industrial the company’s components, and could in Fig. 4, has been configured to and 35% in areas with high water environments: Centro Ricerche Fiat enable it to achieve higher quality and facilitate the exchange of informa- Fig. 3 The NEWMAN project validation strategy stress. Furthermore, the EU contains and Vici. reliability in its optical measurement tion among the project partners and

Disadvantages of nickel-containing Advantages of nickel-free Carburising parameters Heat treatment parameters Value proposition powders powders Samples Temp (°C) Time (min) Atmosphere Pressure (bar) Quench Tempering Volatile nickel prices Cost reduction and stable price High performance at lower cost CH OH+N Astaloy 85Mo 920 20 3 2 1 Oil-76°C 180°C x 60’ Health risks for workers in contact with Removal of the nickel-associated Removal of health risks for workers C.pot=0.8% nickel containing powders health risks in powders handling Astaloy CrA 956 54 C2H2+N2 ≈ 0.005 N2-20 bar 180°C x 60’ Application of hazardous substances Less strict hazardous substances Less safety issues in process regulations regulations management Table 4 Thermo-chemical treatment parameters of 85Mo and CrA powders Reduction of environmental High environmental impact Higher environmental sustainability impact

Table 1 Comparison between conventional powder and nickel-free powder, and the value proposition NEWMAN will entire production process, from The samples for microstructural microscopy, on samples employed for make to the market the choice of powder composition and mechanical characterisation tensile testing, after metallographic to the bench testing of prototypes. were produced using a conventional preparation and chemical etching The main barrier to the use of new industrial sintering cycle. Small bars with Nital 2% (100 ml of ethyl alcohol favour the path towards validation of marketing target and segmentation the NEWMAN project and compares manufacturing technologies and measuring 12 x 12 x 90 mm were + 2 ml of nitric acid). nickel-free steel powders. and, secondly, outlines its implemen- the main advantages of the proposed materials for the production of produced in Höganäs’s laboratory The mechanical characterisation The economic sustainability of tation plan. For simplicity, the ‘go to technology against the technology to mechanical components is the lack facilities. The powders, with the addi- of the samples produced considered the project is an important aspect market’ strategy has been organised be replaced. This comparison is useful of data to support the choices of tion of solid lubricant Lube HD, were their hardness, tensile strength and that must be evaluated to ensure into three stages: value proposition, in outlining the proposed value that is the design engineers. These data compacted in a double-acting press fatigue. HV0.1 hardness tests were the commercial feasibility of any market assessment and implementa- offered to the market along with the include laboratory mechanical at a pressure of 580 MPa for Astaloy carried out in accordance with ASTM developed products. Any project’s tion plan. proposed solution, and what message characterisation to outline the 85Mo, 640 MPa for Astaloy CrA and B933-16, while micro-hardness economic sustainability demon- The value proposition stage must be communicated. material technical datasheet and 680 MPa for Astaloy CrA + 0.6C profiles were obtained according to strates its capability to generate aims to describe the value that the The market assessment stage aims the validation tests of prototypes or compositions. ASTM B934-15 to evaluate the effec- profit and value for the value chain developed nickel-free powders can to identify the target and potential real parts in an industrial environ- The green samples were then tive case depth. – in NEWMAN’s case, from the metal deliver to customers by answering markets of the NEWMAN project. ment. NEWMAN aims to overcome sintered in a laboratory conveyer Tensile tests were performed in powder producer (Höganäs) to the the following questions [6]: Within the project, the target markets this barrier by demonstrating the belt furnace for 30 min at 1120°C accordance with ASTM E8/E8M. Test end-user (CRF and Vici). The main are the automotive sector (CRF • What experiences can push the use of nickel-free steel powders for in a 90/10 N2 /H2 atmosphere. After specimens were machined from the objective is to establish a strategy to customer towards our products? case study) and optical measuring the production of high-performance sintering, the samples were hardened bar samples, with their geometry enter and increase the market share machines market (Vici case study). • Why should the customer buy the components, including laboratory by heat treatment. The Astaloy 85Mo and size being reported in Fig. 5. of nickel-free powders by evaluating The support of actors in the target product? microstructural and mechanical and Astaloy CrA were carburised and The tests were performed with a commercial interest and identifying market helps to move the project • How is value being provided to characterisation of samples made heat treated (Table 4) while, due to its hydraulic machine for mechanical potential stakeholders and how to towards economic validation; proof of the customer? with the powders and the functional high carbon content, the Astaloy CrA tests, under load control, with a load reach them. the good performance of nickel-free and bench tests of prototypes in 0.6C was hardened by induction using increase of 50 N/s. The deformation • What marketing/communication NEWMAN’s ‘go to market’ strategy steel powders in theaforementioned industry-relevant environments. the following parameters: frequency of the sample was measured with a channels are best to make the provides guidelines for future sectors will encourage other compa- As reported in Fig. 4, the 1.8 kHz, heating time 4 sec and oil clip extensometer. The influence of customer aware of the value? marketing and commercial phases. nies, from the same fields or others, first step was to select the most quenching. thermochemical treatment was eval- Firstly, it assesses the added value Table 1 summarises the key points to test the powders and facilitate appropriate nickel-free steel Once the samples had been heat uated by testing four specimens for for the PM market and defines the of the value proposition posed by market entry. powders from a series of composi- treated, several analyses were carried each composition between sintering The implementation plan focuses tions suitable for the production out to fully characterise the micro- and heat treatment and another set on activities for the exploitation of the of high-performance components structure and mechanical properties. from four to seven specimens after technology in connection with dissem- and to optimise the processing Sample density was measured using heat treatment. Powder composition C (%) Cr (%) Mo (%) O tot (%) Fe (%) ination and communication activities. conditions and heat treatment the Archimedes principle, according Fatigue tests were performed Based on the technical and environ- parameters used in the PM process to ASTM962-17. Microstructural using the staircase method according Astaloy 85Mo 0.25 - 0.85 0.07 Bil. mental results of the project and the for these materials. Three nickel- analysis was performed with optical to MPIF Standard 56 using a four- Astaloy CrA 0.25 1.8 - 0.15 Bil. market assessment carried out, a free powders were selected from commercial strategy has been devel- Astaloy CrA 0.6C 0.6 1.8 - 0.15 Bil. an extended group of composi- oped to enter into and consolidate the tions and samples were produced Table 2 Chemical composition of selected powders (wt.%) market for nickel-free powders. in Höganäs’s laboratory facilities 90 mm for microstructural analysis and 17 mm 47 mm 17 mm Performance validation of mechanical characterisation. Particle size distribution The composition and particle size nickel-free steel powders distribution of the three pre-alloyed Powder composition 250 μm 250–150 μm 150–45 μm < 45 μm for PM powders are shown in Tables 2 Ø8 mm R7 mm Astaloy 85Mo 0% 12% 68% 20% and 3. The particle size distribu- The performance validation of nickel- tions have been measured before R7 mm Astaloy CrA 0% 8% 76% 16% Ø4.75 mm free powders for sintering processes the addition of additives such as Table 3 Particle size distribution analysis, carried out by powder sieving includes the optimisation of the lubricants or natural graphite UF4. Fig. 5 Tensile test specimen geometry

90 mm point bending machine and the The hardness profile of Astaloy HardnessHardness Profile Profile 25 mm +/-0.2 25 mm +/-0.2 (1:1) following test parameters: 100 85Mo, evaluated on the sample after 1000 18 mm +/-0.1 Hz, Stress Ratio R=σmin/σmax = -1, carburising and heat treatment, is Runout= 5,000,000 cycles, Load reported in Fig. 9. The case depth 800 A +0 -0.05 increase step: 25 MPa, for Astaloy is 1.5 mm, with a hardness close to Ø12 mm R20 mm 85Mo. Fatigue specimen geometry 550 HV reached in the core. 600 B +/-0.1

Ø6 mm - Diameter A and B to be concentric is reported in Fig. 6. The fracture The results of tensile strength

R20 mm within 0.02 mm surfaces were further analysed using testing for Astaloy 85Mo are reported HV0.1 400 - Test section (18 mm) shall be free scanning electron microscopy (SEM- in Table 5. After carburising and of nicks, dents and scratches, and FEG). heat treatment, the ultimate tensile 200 Astaloy 85Mo circumferential tool marks visible at Since the characterisation stage strength (UTS) of the material was 20 x magnification. Ra 0.3 Rz 0.5 enabled the collection of a wide significantly increased, but its ductility 0 dataset of results for the three was reduced. It is worth noting that Fig. 6 Rotating bending fatigue: test-specimen geometry 0.0 0.5 1.0 1.5 2.0 2.5 3.0 analysed compositions, this article it is not possible to differentiate Depth [mm] will report in full only the analysis of between UTS and Yield Strength Astaloy 85Mo, as an example of the (YS) due to the negligible elongation Fig. 9 Hardness profile of Astaloy 85Mo adopted approach and the obtained to failure (A%). Furthermore, the results. Fig. 7 and Fig. 8 show standard deviation of the tensile data the microstructures of samples is very low, despite the presence of produced with Astaloy 85Mo, before porosity that may affect data disper- Density UTS [MPa] YS [MPa] Elongation% Samples and after heat treatment. The sion. [g/cm3] (St.Dev.) (St.Dev.) (St.Dev.) small black areas in Fig. 7 repre- The fatigue tests showed good 311 190 5.43 Astaloy 85Mo sintered sent pores, typical of the sintered fatigue behaviour for heat treated (3) (4) (0.00) component. In the sintered samples, Astaloy 85Mo samples. The material’s 7.121 Astaloy 85Mo carb. + 932 932 0.15 a ferritic-pearlitic microstructure fatigue strength (for 50% probability of quench + temp. (26) (26) (0.03) can clearly be recognised, with a failure) was 463 MPa with a standard preponderance of ferrite. After the deviation of 19 MPa, while the ratio Table 5 Density and tensile properties of Astaloy 85Mo, before and after carburising treatment, quenching between fatigue strength and UTS carburising, quenching and tempering and tempering steps, the micro- was about 0.5. The data confirmed structure is completely martensitic that the chosen PM process and at sample surface (Fig. 8a), and heat treatment parameters enabled martensitic-bainitic in the core of the production of nickel-free, high- microstructure. Fig. 11 shows the et al [8]. According to Torralba et al, the sample (Fig. 8b) [7]. The different performance, homogeneous PM steel fracture surface of a tensile spec- the presence of bainite grains, along microstructures can be explained by samples. imen for Astaloy 85Mo. The surface is which the fracture preferentially the presence of molybdenum, which The morphology of the tensile frac- characterised by pores; interparticle propagates, leads to a local plastic Fig. 7 Optical micrograph of Astaloy 85Mo sample after sintering. The light delays the pearlitic transformation ture surfaces of sintered nickel-free ductile dimples located at particle flow and to the formation of dimples, grey areas represent a ferritic microstructure, the dark grey areas a pearlitic with the subsequent development of powders is influenced by the pres- necks; and some small cleavage while brittle fractures occur in corre- microstructure the bainitic structure. ence of pores and the heterogeneous facets, as also reported by Shykula spondence to martensitic zones [9].

a) b) a) b) Fatigue results 1000 900 800 700 600 500

400 932 UTS [MPa]

300 UTS [MPa] (50%)

200 463 D

100 σ 0 Astaloy 85Mo σD (50%) 463 UTS [MPa] 932

Fig. 8 Optical micrographs of Astaloy 85Mo samples after carburising and heat treatment, showing a) a martensitic Fig. 10 Rotating bending fatigue Fig. 11 Astaloy 85Mo tensile fracture surface: a) 1000 x b) 5000 x microstructure at the surface, and b) a martensitic-bainitic core microstructure results: Astaloy 85Mo

the use of nickel-free powders at the b) c) a) b) environmental level. The output of the study will be of great interest to CRF, a) Vici and other actors from industry that use Powder Metallurgy production techniques and might move to nickel- free powders.

Conclusion

Nickel-free steel powders represent a solution to increase the sustainability Fig. 13 Components selected for the validation of nickel-free PM parts in the of Powder Metallurgy. The absence NEWMAN project – a) the sliding sleeve for an automotive gearbox, and b) a of nickel content strongly reduces pinion for an automatic measuring machine the health risks for workers and the Fig. 12 Astaloy 85Mo fatigue fracture surface: a) entire fracture surface 34x, b) propagation region 5000 x, c) final failure costs related to the handling of the region 5000 x powders. Thus, to demonstrate the high performance of the nickel-free Federico Della Ricca [5] U National Minerals Information powders analysed within the project Customer Technical Support Center, ‘Mineral Commodity Summa- will provide major benefits in paving Höganäs AB ries 2020,’ 2020. For Astaloy 85Mo specimens, the and dies used in the PM process At the project’s conclusion, all of the way for sustainable manufacturing www.hoganas.com/en/ fatigue fracture surface analyses have allowed the manufacture of very the data will be available to demon- processes. The NEWMAN project is Tel: +39 340 577 04 36 [6] M J Lanning, ‘Try taking your value highlighted that fatigue cracks nucle- near-net shape components, limiting strate the benefits that the use of demonstrating the actual impact of [email protected] proposition seriously - Why delivering ated in the outer zone of the speci- the machining steps and reducing the nickel-free steel powder can provide nickel-free powders for the production winning value propositions should be mens, close to large pores (Fig. 12). manufacturing cost, as well as mate- in terms of cost, production times of high-performance components. The www.newman-project.eu but usually is not the core strategy The crack propagation region is rial waste. and environmental impact, compared validation approach allows researchers for B2B (and other businesses),’ characterised by typical ductile Preliminary structural FEM to traditional materials and produc- to verify the advantages in terms of Industrial Marketing Manage- fatigue striations, while the final analyses, based on microstructural tion processes. economics, performance and envi- References ment, Vol. 87. Elsevier Inc., pp. failure region is characterised by the and mechanical characterisations, The achievement of environ- ronmental impact. The continuous 306–308, May 1, 2020, doi: 10.1016/j. same fracture morphologies already confirm that Astaloy 85Mo is suitable mental sustainability, already in its exchanges among the validation steps [1] M E Peralta Álvarez, M Marcos indmarman.2019.10.011. described for the tensile specimens for the production of both the sliding early stages, is essential to launch create powerful synergies in order to Bárcena, and F Aguayo González, [7] M Günen and A Bakkaloglu, ‘Influ- (cleavages and dimples). sleeve and the pinion, though further materials onto the market with reach remarkable achievements in ‘On the sustainability of machining ence of sinter-hardening on micro- optimisation of the carburisation a low impact for the planet. The improving PM sustainability. processes. Proposal for a unified structures and mechanical properties process is needed in order to obtain a improvements to environmental framework through the triple bottom- Nickel-free steel PM of Astaloy Mo-based steels,’ Mater. hardened depth of about 0.8 mm, as sustainability possible through the line from an understanding review,’ components Lett., Vol. 251, pp. 201–205, Sep 2019, suggested by the designers. use of nickel-free powders are Authors Journal of Cleaner Production, Vol. doi: 10.1016/j.matlet.2019.05.066. In the NEWMAN project’s second demonstrated through the LCA 142. Elsevier Ltd, pp. 3890–3904, The last period of the NEWMAN year, the prototype parts identi- methodology. The powders developed Giulia Broglia PhD Jan 20, 2017, doi: 10.1016/j. [8] P Shykula, R Oro, E Dudrova, project’s first year was dedicated to fied above will be produced on an during the NEWMAN project will be Communication & Dissemination jclepro.2016.10.071 M Campos, J M Torralba, and S the selection of components to be industrial pressing and sintering compared with conventional powders Manager Bengtsson, ‘Microstructure and frac- validated for production with nickel- line, using the process parameters and nickel-containing steels, using [2] J R John Elkington, ‘Cannibals CRIT srl ture behavior of high strength hybrid free powders and the optimisation optimised during the first phase the methodology described in the With Forks: The Triple Bottom Line of www.crit-research.it/en/ powder systems based on Fe-[Mo]- of prototype geometries for the of the project. These parts will ISO 14040 standard (ISO, 2006) in 21st Century Business,’ J. Bus. Ethics, Tel: + 39 059 776 865 C + Cr-Ni-Mo-Mn master alloy,’ in PM process. A sliding sleeve was then undergo heat treatment and order to collect data comparable with Vol. 23, No. 2, pp. 229–231, 2000, doi: [email protected] Proceedings of the World Powder selected as the test components for analysis to evaluate the success of other studies or products. Different 10.1023/A:1006129603978 Metallurgy Congress and Exhibition, CRF’s case study, shown in Fig. 13a, the production process, compared to categories of impact will be consid- Prof Alessandro Morri [3] J M C Azevedo, A CabreraSer- World PM 2010, 2010, Vol. 3. while a pinion was selected for Vici’s laboratory results. After the valida- ered, including the influence on NEWMAN Coordinator renho, and J M Allwood, ‘Energy and case study, shown in Fig. 13b. tion of the production parameters, climate change and the material’s Department of Industrial Engineering, material efficiency of steel powder [9] J M Torralba, L Esteban, E The characterisation results have in terms of microstructure and carcinogenic effects on humans. University of Bologna metallurgy,’ Powder Technol., Vol. Bernardo and M Campos, ‘Under- been used to modify the design of the mechanical properties, the final Firstly, the study aims at analysing www.unibo.it/en/homepage 328, pp. 329–336, Apr 2018, doi: standing contribution of micro- two components, considering both validation step of bench testing will the hotspots of the approach to Tel: +39 051 20 9 3463 10.1016/j.powtec.2018.01.009 structure to fracture behaviour of the mechanical properties of the be carried out. The prototype sliding support the environmentally sustain- [email protected] sintered steels,’ Powder Metallurgy, material and the peculiarities of the sleeve will be mounted on a real able development of nickel-free [4] ‘EPMA launches R&D project on Vol. 57, No. 5, pp. 357–364, 2014, doi: PM process compared to conven- gearbox and tested following the powders for use in Powder Metal- Prof Augusto Bianchini sustainability of press & sinter PM,’ 10.1179/1743290114Y.0000000119 tional manufacturing processes, manufacturer’s validation cycles. The lurgy. Secondly, the environmental NEWMAN Coordinator on PM Review, 2020, https://www. such as forging and machining. The pinion will be mounted on a special impacts of CRF and Vici’s products www.unibo.it/en/homepage pm-review.com/epma-launches- modification of a component’s design test bench that recreates the real will be compared with benchmark Tel: +39 0543 374 438 rd-project-on-sustainability-of- and the proper design of the tools operating conditions. products, identifying trade-offs from [email protected] press-sinter-pm/

ABSTRACT SUBMISSION DEADLINE: APRIL 2, 2021 Call for Presentations Euro PM2020: High-temperature properties, corrosion and wear

Powder Metallurgy and performance of PM hardmetals PMTi Additive Manufacturing 2021 of Titanium September 15–17, 2021 • McGill University • Montréal, Canada

Within the programme of the well-received Euro PM2020 Virtual Congress, held Global experts on powder metallurgy and October 5–7, 2020, and organised by the European Powder Metallurgy Association additive manufacturing processing of titanium (EPMA), technical sessions showcased the latest studies on the high-temperature properties, corrosion and wear performance of hardmetals and titanium alloys will gather for academic produced by Powder Metallurgy. In this article, Dr David exchange and technology transfer in Montréal, Whittaker provides a summary of each paper presented Canada. during this session, highlighting the key findings. Topics include: ■ Powder production ■ Compaction and shaping ■ Metal injection molding (MIM) Additive manufacturing The effect of surface tools can decrease the cutting forces, Finite element methods have, there- ■ texturing on the coefficient of friction, surface rough- fore, emerged as a good approach to ■ Sintering temperature distribution in ness and tool wear when compared predict these temperatures. Mechanical properties with an untextured cutting tool. It has In the study reported, the effects ■ WC-Co cutting tools also been discovered that texturing of different cross-hatched micro- ■ Microstructure vs. property relationships the rake face leads to a lower patterns on the temperature distribu- The first study of high-temperature PM Ti alloys including TiAl temperature rise than texturing the tion in a WC-10 wt.% Co cutting ■ properties was presented by flank face. tool were assessed. Finite element PM Bio Ti materials B Guimaraes, F S Silva and G Miranda ■ However, direct temperature analyses were performed using (University of Minho, Portugal) and Modeling measurement at the cutting tool COMSOL Multiphysics software. The ■ C M Fernandes and D Figueiredo is very difficult, making it hard to analysed geometry for the thermal ■ Applications (Palbit S A, Portugal) and concerned quantify the influence of surface model consisted of a tool holder, a the effect of surface texturing on texturing on temperature reduction. cutting tool and a shim, as shown in temperature distribution during the After five successful conferences held in Australia, service of WC-Co cutting tools [1]. New Zealand, Germany, China, and the United States, Machining processes generate a PMTi is headed to Canada for the first time. high temperature in the cutting zone Cutting tool due to plastic deformation, inducing Tool holder WC-Co AISI 1045 steel Peak Groove a wear increase and, consequently, width (P) width (G) Conference Co-Chairs: reducing the lifetime of cemented ■ Louis-Philippe Lefebvre, National Research Council Canada carbide cutting tools. Vladimir Brailowski, ETS Montréal, Canada Several studies in the literature ■ have reported the benefits of surface Mathieu Brochu, McGill University, Canada ■ texturing of WC-Co cutting tools in Shim improving anti-adhesion, wear resist- WC-Co ance, cutting force and temperature, Depth (D) Sponsored by: and friction coefficient. For example, Metal Powder Industries Federation the presence of micro-scale grooves Fig. 1 Geometry of the analysed thermal model (tool holder, cutting tool and on the rake face of WC-Co cutting shim) [1] Visit pmti2021.org to submit an abstract 98 Powder Metallurgy Review Spring 2021 © 2021 Inovar Communications Ltd © 2021 Inovar Communications Ltd Spring 2021 Powder Metallurgy Review 99 Euro PM2020 - PM hardmetals | contents | news | advertisers | events | website | e-newsletter | | contents | news | advertisers | events | website | e-newsletter | Euro PM2020 - PM hardmetals

Fig. 1. The tool holder was made dimensions being presented in 900 WC-Co [23] AISI 1045 [24] of AISI 1045 steel, while the shim Table 2. The cross-hatched pattern 800 T (K) k T (K) k and cutting tool were both made of was designed to begin 300 μm 700 298.15 90.00 298.15 45 WC-Co hardmetal. from the cutting edge, since The material properties used results from the literature showed 600 473.15 73.44 473.15 41.03 in this study for WC-Co and AISI a better performance for textures 500 573.15 63.36 573.15 38.57 1045 are presented in Table 1. The on cutting tools beginning at this governing heat transfer equation distance. 400 Thermal Conductivity, 673.15 57.44 673.15 36.31 -1 -1 ruling this problem is presented Fig. 3 presents the tool k (W m K ) 300 773.15 52.91 773.15 33.77 (°C) Temperature (temperature dependent) in the following equation, based maximum temperature versus A 200 873.15 49.10 873.15 31.43 on nonlinear transient three- time for the nine cross-hatched B C dimensional heat conduction in a micro-patterns (experiments A to I) 100 973.15 47.20 973.15 29.04 rectangular coordinate system: and also for the untextured surface J (experiment J). These results 0 1073.15 45.94 1073.15 26.65 0 10 20 30 40 50 60 show that the addition of surface Specific heat, Cp (J kg-1 K-1) 220 [23] 420 [15] Time (s) + + = textures to a WC-Co cutting tool -3 𝑇𝑇𝑇𝑇 𝑇𝑇𝑇𝑇 𝑇𝑇𝑇𝑇 𝑇𝑇𝑇𝑇 Density, (kg m ) 14400 [23] 7800 [15] ∂ �𝑘𝑘𝑘𝑘 ∂ � ∂ �𝑘𝑘𝑘𝑘 ∂ � ∂ �𝑘𝑘𝑘𝑘 ∂ � 𝐶𝐶𝐶𝐶𝑝𝑝𝑝𝑝 ∂ leads to a considerable decrease in 𝑥𝑥𝑥𝑥 𝑥𝑥𝑥𝑥 𝑦𝑦𝑦𝑦 𝑦𝑦𝑦𝑦 𝑧𝑧𝑧𝑧 𝑧𝑧𝑧𝑧 ρ 𝑡𝑡𝑡𝑡 ∂ ∂ ∂ ∂ ∂ ∂ ∂ the maximum temperature when Table 1 Material properties used in the numerical simulations [1] ⍴ where k is the thermal conduc- compared with a conventional

tivity, ρ the density and Cp the cutting tool. 900 specific heat,T is the temperature, Prediction of the temperature 800 (b) 40 t stands for time and x, y, z are the distribution in the cutting tool rectangular coordinates. versus time for experiments A, 700 )

2 For the initial condition, the D, G and J has shown that the 600 whole system was assumed to be maximum temperature in the 30 at room temperature (20°C), when cutting tool is always at the cutting 500 the machining process started at edge (place of applied heat flux), 400 t = 0 seconds. The heat flux defined regardless of time. In all cases, 20 300 at the tool-chip interface (red area as time passes, the heat dissi- (°C) Temperature Heat Flux (MW/m D in Fig. 2a was chosen based on pates through the solid material 200 E reported experimental work and by conduction. For these experi- F (a) 10 100 reproduced in Fig. 2b. ments, it is also possible to identify J All of the other surfaces that the surface texture allowed a 0 dissipate heat to the surroundings significant temperature reduction 0 10 20 30 40 50 60 0 Time (s) 0 10 20 30 40 50 60 during the machining process, in the cutting zone and a faster Time (s) being cooled using air with a cooling. convective heat transfer coef- The absolute maximum Fig. 2 a) Tool-chip interface, b) applied heat flux at the tool-chip interface [1] ficient of 20 W -2m K-1. The related temperatures reached in the boundary condition was: different experiments are shown 900 in Fig. 4. It is possible to conclude that, for textures having equal 800 Experiment Groove width (μm) Peak width (μm) Depth (μm) = ( ) 𝑇𝑇𝑇𝑇 groove and peak widths (G = P), the 700 A 50 − 𝑘𝑘𝑘𝑘 ∂ ℎ 𝑇𝑇𝑇𝑇 − 𝑇𝑇𝑇𝑇 𝑛𝑛𝑛𝑛 ∞ absolute maximum temperature ∂ 600 B 100 100 100 where k is the thermal conduc- increases with the increase in tivity, T is the temperature and h depth (e.g. experiments A, B and 500 C 150 the heat transfer coefficient. C). Similar results can be found in 400 D 50 To ensure the most realistic the literature, where this behaviour 300 E 200 200 100 results possible, the effect of has been attributed to the aspect (°C) Temperature thermal contact resistance was ratio increase, with greater depth G 200 H F 150 based on a consideration of a 1 μm allowing air entrapment which 100 I G 50 gap filled with air, with a value then, consequently, acts as an J of 3.8 × 10-4 m2 K W-1. In order to insulation barrier to conduction. 0 H 300 300 100 assess the influence of different For equal depths, by increasing 0 10 20 30 40 50 60 I 150 dimensions, namely groove and the groove and peak widths, an Time (s) peak width/depth, on the tempera- increase in the maximum tempera- J Untextured ture distribution in the cutting tool, ture ensues (e.g. experiments A, D Fig. 3 Simulation results for the maximum temperature versus time for the Table 2 Cross-hatched micro-pattern dimensions used for numerical several cross-hatched micro- and G), due to an increase in tool- cross-hatched micro-pattern dimensions presented in Table 2 and untextured simulation [1] patterns were simulated, with their chip contact area. cutting tool (experiment J) [1]

size and Co binder content between grains were investigated at different 879 900 6–11%) of WC-Co were identified temperatures, by means of spherical using a Scanning Electron Micro- nanoindentation (5 μm radius), from 40 A scope (SEM), equipped with an ambient to 600°C. A load of 150 mN 850 B Electron Backscattered Diffraction was applied to individual grains over C (GPa) (EBSD) detector. 30 s, held for 30 s and removed over D Nanoindentation measurements 30 s. 800 E WC-Prismatic 30 F at room temperature (RT) and high When plotting the hardness of G temperature (HT) were performed grains as a function of grain dimen- 750 736 758 714 H in load control, using a maximum sions, a clear downward trend was I load ranging from 10–16 mN observed as the dimensions of the 709 732 H Hardness, 700 687 J to reach indentation depths in grains increased. To understand the 20 Maximum temperature (°C) Maximum temperature the range of 100–200 nm. Each mechanism behind the change in 664 685 710 650 0 nanoindentation cycle consisted hardness with varying grain dimen- 300 of: applying the load over 30 s, sions, the hardness of the prismatic 0 2 4 6 8 10 12 P G 50 200 holding the maximum load for 10 s grains was plotted as a function of Distance indent-boundary, L (μm) 100 G = P WC-Prismatic D D (μm) 100 and unloading over 20 s. Thermal the distance between the indent 150 drift correction data were collected and the nearest grain boundary Fig. 5 Grain size/geometry effect. Hardness data obtained at room temperature

at 90% unloading over 60 s. At (LWC-Prismatic). Fig. 5 shows an obvious from WC prismatic grains as a function of the distance from the indent to the Fig. 4 Absolute maximum temperatures for different cross-hatched micro- temperatures higher than ambient, increase in hardness for indents nearest grain boundary [2] patterns [1] an additional time of 180 s was made less than 2–3 μm away from a used to thermally equilibrate the grain boundary, in agreement with {indenter + sample} system prior to the Hall-Petch relation and indicative indentation. of a strengthening effect, occurring ambient to 700°C. The hardness of measured for all WC grains at 700°C, The results obtained for experi- WC-Co hardmetals are used as The Oliver-Pharr method was through a reduction in dislocation both grain orientations remained compared with hardness measured ment J show that an absolute cutting, mining and drilling tools used to extract hardness values, mobility near the grain boundary. unchanged from ambient to 100°C: under ambient conditions. maximum temperature of 879°C is because of their high hardness and while the plastic index of the In addition to the effect of grain about 29 and 53 GPa for the prismatic Anisotropy in the deformation of achieved in a conventional WC-Co strength, combined with high fracture indented grains was also meas- size, the anisotropy of WC grains was and basal orientation, respectively. A the WC grains was also investigated cutting tool. Among all of the tested toughness and wear resistance. ured from ambient to 700°C. The also investigated. Whilst indenting progressive decline in hardness was by means of the plastic index (the cross-hatched micro-patterns, Because hardmetals reach high location of the indent and the WC grains with various orienta- measured for all WC grains as the ratio of the indentation plastic work the lowest maximum tempera- temperatures of around 700°C when measurement of the distance tions from different WC-Co grades temperature increased from 100 to [area under the P-h curve] over the ture was found for experiment A, used as tools, understanding their between the indent and the nearest consisting of varying WC grain 700°C, with basal planes more signif- overall indentation work [plastic + where a significant reduction in performance in these environments grain boundary was performed dimensions, the hardness of both icantly affected up to 400°C followed elastic recovery]) in the whole range the maximum temperature was is crucial. in the SEM. Nanoindentation was prismatic and basal WC grains was by a more drastic drop at about of temperatures (Fig. 6b). Under achieved, of around 25% (215°C). At microstructure scale, WC-Co performed from room tempera- measured and compared using an 500–600°C (Fig. 6a). A reduction in ambient conditions, the plastic During the machining process, is heterogeneous, with performance ture to 700°C in a high-vacuum average of all indented grains, from hardness in the range of 70–75% was indices of both prismatic and basal the maximum temperature is being governed by its design. While (10-6 mbar) nanoindentation system attained at the cutting edge. This this design has been investigated to equipped with resistive heating on temperature reduction, achieved improve the performance of WC-Co both the indenter and the sample. through the use of the surface using modelling with micro (or nano) Berkovich indents were used; texturing, will have a positive impact mechanical data measured at room diamond indenters up to 300°C and a)A A060 0 B b)B in the cutting tool, extending its temperature, information on high- cubic Boron Nitride (cBN) indenters (000)(000) lifetime. temperature properties is still very at higher temperatures. Indirect 050 0 (00)(00) 001.0 limited, especially at the nanoscale. verification of the indenter after (0)(0) Mechanical anisotropy of WC single indentation at each temperature 040 0 High-temperature crystals has previously been reported was carried out by conducting the nanomechanical behaviour at room temperature, but the study indentation at room temperature 030 0 000.8 of WC grains in WC-Co has extended this work to extract on a referenced material (fused 020 0 the hardness dependency of WC on silica) to assess the change in the

hardmetals H (GPa) Hardness, 000.6 crystal orientation at temperatures area function of the indenter and, ardness (Pa) 010ardness (Pa) 0 Next, F De Luca, H Zhang, V Tong ranging from ambient to 700°C. Also therefore, reduce hardness meas- Basal/Prismatic plasticity (a.u.) Basal/Prismatic plasticity and K Mingard (National Physical studied was the effect of WC grain urement errors. 0 0 0 00000000000000000000000000000 asal/Prismatic plasticity (au) asal/Prismatic plasticity (au) Laboratory, UK) reported on a study size on hardness, from measurement During indentation, both the 0 100 200 300 400 500 600 700 0 00000100000020000003000000400000050000006000000700 of the high-temperature nanome- of grains with dimensions ranging indenter and the sample were emperatureTemperature,emperature T (°C) (˚C) (˚C) emperatureemperatureTemperature, T (°C) (˚C) (˚C) chanical behaviour of WC grains from 1 to 1000 μm2. tuned and thermally stabilised in WC-Co hardmetals [2]. A more To examine a wide range of grain in near-contact to achieve an Fig. 6 Mechanical properties of WC grains from ambient to high temperatures. a) Hardness(1210)(1210) (0110) of (0110) (0001) and(0001) (1210) detailed description with additional sizes, individual WC grains in three isothermal contact. Plastic (1210)prismatic (0110) and (0001) basal WC grains and b) the ratio of plastic index between basal and prismatic grains from ambient data is reported in [3]. grades (with 1, 5 and 15 μm mean WC deformation mechanisms in WC to 700°C [2]

PrismaticPrismatic Basal The authors concluded that the (1) (2) (3) Density Gavg Hardness KIC collected mechanical information (g.cm3) (μm) (HV30) (MPa.m1/2) A B C D from WC grains at high temperatures represents important data WC-Co 14.30 1.00 1430 12 for manufacturers of hardmetals to WC-FeCoNi 14.12 0.81 1375 12.6 predict the performance of WC-Co in WC-NiCrCoMo 14.21 0.75 1518 10.9 RT service conditions. RT WC-NiCrMo 14.33 0.52 1609 8.8

Table 3 Physical and mechanical properties of the tested samples (1 – 5 µm 2 µm 5 µm 2 µm The influence of temperature on the Archimedes principle, 2 – Average of WC grain sizes, 3 – Palqmvist method) [4] E F G H corrosion resistance of hardmetals

In a separate session, attention was An important factor influencing The physical and mechanical turned to corrosion and wear resist- the performance of hardmetals is properties of the WC-Co, WC-FeCoNi, RT HT ance of hardmetals, firstly in a study temperature. In aqueous environ- WC-NiCrCoMo and WC-NiCrMo reported by A M Ferro Rocha, Pedro ments, temperatures are expected composites are presented in Table 3. Silva, A M R Senos and A C Bastos to be lower than the boiling point of All samples had satisfactory mechan- 2 µm 5 µm 2 µm 5 µm (University of Aveiro, Portugal) and water, but often they will be substan- ical properties, within the acceptable F Rodrigues and J Sacramento tially higher than room temperature. range for this type of material. In Fig. 7 Plastic deformation in WC basal and prismatic grains at room and high temperature. Top view and cross-section (DURIT Ltda, Portugal) [4]. However, most of the published addition, no undesirable phases, such ECCI micrographs of WC prismatic and basal grains after spherical indentation (5 μm radius) at room temperature (A-B Hardmetals are often exposed work on the corrosion behaviour of as free carbon or eta phase, were and C-D, respectively) and 600°C (E-F and G-H, respectively). The green dashed arrows indicate the milling direction to corrosive environments such as hardmetals was performed at room found, as can be seen in the micro- used to acquire the cross-sectional ECCI micrographs, while the white and orange arrows pinpoint the location of cracks refrigerant liquids, cutting fluids, temperature, leaving the effect of graphs and XRD patterns in Fig. 8. in the imprint and in the cross-section of the grains, respectively [2] lubricants, chemicals and the acidic temperature on corrosion resistance Corrosion measurements were environments formed in mining of hardmetals unknown. performed at room temperature and petrochemical uses. Usually, The reported study was intended (22 ± 2°C), at 60 ± 1°C and at near in near-neutral and acidic environ- to address this gap by analysing the water boiling point (90 ± 2°C), using grains were found to be similar. As with prismatic slip on planes of the steps in the cross-section of the ments, corrosion happens in the effect of temperature from room to an aqueous solution of 0.5 M NaCl. the temperature increased, plas(1010)- (0110)type (1100), (1010)(1010) and (0110) (0110) (1100) over (1100) a indented prismatic grain. On the binder phase; in alkaline media, it near boiling water temperature on The samples were electrically ticity in prismatic grains appeared to much smaller plastically deformed other hand, no crack was observed is the WC phase that is believed to the corrosion of four hardmetals, connected to a copper wire and become more and more pronounced region were observed in the top-view in the surface of the basal grain, be dissolved. Once corroded, the whose corrosion behaviour at room embedded in epoxy resin, leaving than that in basal grains, up to ECCI micrograph of the indented but large cracks were observed to surface properties are lost and wear temperature had previously been only one face exposed to the testing 500°C. However, at 600°C, basal basal grain at room temperature propagate along the cross-section, resistance is drastically reduced, studied by this group. medium. The grinding of the samples grains underwent a large plastic (Fig. 7c). In the prismatic grain, the within the prismatic plane. with a consequent decrease in the Four hardmetal composites was carried out with a sequence of deformation, reducing the offset with cross-sectional ECCI micrographs Hence, the ECCI observations lifetime of tools and equipment. One (WC-Co, WC-FeCoNi, WC-NiCrCoMo diamond discs, starting with 75 μm, prismatic grains. show intercepting slip lines either identified preferential directions for way to overcome this problem is to and WC-NiCrMo) were prepared then 54 μm and finally 18 μm granu- The formation of plastic deforma- side of the indent consistent with the stresses to be accommodated use alternative binders. Nickel, for using common Powder Metallurgy lometry, using tap water. Finally, the tion near the spherical indent was the top down view (Fig. 7b). For the through plastic flow or cracking. example, is known to increase the methods and their binder content samples were rinsed with distilled investigated by electron microscopy, basal cross-section, the slip and While it is unclear when the cracks corrosion resistance of hardmetals. was near 18 vol.%. water and ethanol. To ensure that using the Electron Channelling plastic deformation is confined to were formed during the nanoinden- Contrast Imaging (ECCI) technique. the region very close to/beneath the tation cycle – whether upon loading, ECCI micrographs of indented WC indent, propagating vertically down- creep or unloading – the formation grains show evidence of plastic defor- wards (Fig. 7d). of cracks at high temperatures WC WC mation that occurred in the vicinity As the temperature increases, might be the result of accumulated WC WC of the indent, via local changes in those features observed at room stresses at the indenter tip, which electron channelling contrast (local temperature became more were not accommodated through WC lattice defects causing changes in pronounced, with a higher density the activation of slip systems within WC pixel intensity). The top-down view of slip lines and a larger plastic the prismatic plane. Cracks tend to Fe(α) FeNi ECCI micrograph of the indented field, also preferentially propagating preferentially propagate within the FeNi prismatic grain at room temperature along the prismatic plane. At 600°C, prismatic plane and perpendicularly

intensity (a.u.) intensity WC-FeCoNi (a.u.) intensity Ni reveals the presence of slip lines, both grains failed through severe to activated slip lines, which, in WC-NiCrMo Ni Co parallel to (1010)plane traces (0110) of (1100) and cracking, with slip lines triggered agreement with ECCI observations, WC-Co (1010) (0110), along(1100) which plastic deforma- farther away from the indent and a indicates that stresses can only be WC-NiCrCoMo tion tends to propagate (Fig. 7a). plastic field covering the entire grain plastically released along preferen- 20 30 40 50 60 20 30 40 50 60 On the other hand, slip lines inter- area. Cracks appeared to propagate tial directions within the prismatic 2 theta (°) 2 theta (°) cepting each other at 60°, consistent along the prismatic plane, forming plane. Fig. 8 Left; SEM micrographs and right; XRD patterns of the tested composites [4]

0.1 0.1 0.1 -2 -1 ~ 20°C ~ 60°C ~ 90°C Ecorr (mVSCE) icorr (μA cm ) βa (mV dec ) 0.0 WC-NiCrMo 0.0 WC-NiCrMo 0.0 20°C 60°C 90°C 20°C 60°C 90°C 20°C 60°C 90°C

-0.1 WC-NiCrCoMo -0.1 -0.1 WC-NiCrMo WC-Co -360 -429 -418 17.2 19.5 49.5 111 91.0 70.0 WC-NiCrCoMo WC-FeCoNi -360 -397 -432 18.4 20.3 17.9 151 100 56.0 -0.2 WC-FeCoNi -0.2 -0.2 WC-NiCrCoMo WC-NiCrCoMo -14.7 -119 -253 0.37 1.02 23.0 175 136 148

E vs SCE / V E vs -0.3 SCE / V E vs -0.3 SCE / V E vs -0.3 WC-Co WC-NiCrMo -46.1 -66.2 -145 0.70 0.38 5.26 268 114 319 WC-FeCoNi WC-FeCoNi -0.4 -0.4 -0.4 WC-Co WC-Co Table 4 Electrochemical parameters extracted from polarisation curves [4] -0.5 -0.5 -0.5 0 10 20 30 40 50 60 0 10 20 30 40 50 60 0 10 20 30 40 50 60 Time / min Time / min Time / min

Fig. 9 Corrosion potential of all samples in the first hour of immersion in 0.5 M NaCl at RT, 60°C and 90°C [4] tions, which, in this context, mean the sample, can be of the electrical the smaller amount of O2, due to the

lower corrosion rates. The elec- double layer (Cdl) at the solid/liquid lower solubility at high temperatures.

trochemical parameters indicated interface or of a passive film (Cpass). Instead of following the common the following increasing order of The resistive response at lower approach of using equivalent electric corrosion resistance: WC-Co ≈ frequencies is due to the charge circuits to analyse the EIS data, a all samples had the same exposed EIS measurement with a sinusoidal temperatures. Using the Tafel extrap- WC-FeCoNi < WC-NiCrCoMo < transfer resistance (R ) or the simple ranking of general behaviour surface area (0.24 cm2), insulating signal perturbation of 10 mV (rms), in olation technique, electrochemical ct WC-NiCrMo. resistance of the passive film (R ), was made, with the assumption that tape with a circular hole was used. the frequency range between 105 and parameters, such as the corrosion pass -3 Fig. 11 shows the impedance sample dependent. In some cases, higher impedance corresponds to All electrochemical experiments 5 x 10 Hz (10 points per frequency potential (Ecorr), corrosion rate (icorr) measured after 1 h of immersion in there is a second time constant higher corrosion resistance. The – open circuit potential monitoring, decade). Finally, current-potential and the anodic Tafel slope (βa), were 0.5 M NaCl at RT, 60°C and 90°C. at low frequencies, attributed to impedance moduli, measured at polarisation curves and electrochem- curves (anodic sweeps) were obtained extracted from the polarisation The response at higher frequen- either R /C (in passive systems) low frequency (5 mHz), are given in ical impedance spectroscopy (EIS) using a scan rate of 1 mV/s, starting at curves, and are presented in Table 4. ct dl cies (105 to 103 Hz) is related to the or to a diffusion process (active Table 5. The results showed the same – were conducted using a potentiostat -25 mV vs open circuit potential (Eoc). The corrosion potentials were in solution resistance. At interme- systems). Diffusion control seems ranking as determined previously: in a typical three-electrode design. The measured open circuit poten- line with those observed in the Eoc diate frequencies, there is a capac- to be more pronounced at higher WC-Co ≈ WC-FeCoNi < WC-NiCr- The embedded samples served as the tials (Eoc) of all samples are shown monitoring and became more nega- itive response that, depending on temperatures, possibly because of CoMo < WC-NiCrMo. working electrode, and a platinum in Fig. 9. The sample of WC-NiCrMo tive with increasing temperature. The wire was used as the counter. A satu- presented more positive values corrosion rates tended to become rated calomel electrode (SCE) was amongst the samples, at all studied higher with increasing temperature. used as reference. To avoid the inter- temperatures. WC-Co and WC-FeCoNi WC-Co and WC-FeCoNi showed ference of temperature, the reference always showed more negative values similar corrosion rates, the highest 105 105 105 electrode was placed in a separated in this range of temperatures. There among all of the composites at all WC-Co WC-Co WC-Co compartment with a bridge containing was a general tendency for a potential temperatures, whereas WC-NiCrMo WC-FeCoNi WC-FeCoNi WC-FeCoNi 4 4 4 the same 0.5 M NaCl solution. decrease as temperature increased. presented the lowest corrosion 10 WC-NiCrCoMo 10 WC-NiCrCoMo 10 WC-NiCrCoMo WC-NiCrMo WC-NiCrMo WC-NiCrMo

During the first sixty minutes of Fig. 10 shows the current-potential rates at temperatures above RT. 2 103 103 103

immersion, the open circuit potential curves measured after 1 h of immer- Higher Tafel slopes are associated cm

(Eoc) was recorded, followed by the sion in 0.5 M NaCl for all tested with slower electrochemical reac- Ω 102 102 102 |Z| /

10 10 10 ~ 20°C ~ 60°C ~ 90°C 0.8 0.8 0.8 1 1 1 ~ 20°C ~ 60°C ~ 90°C WC-NiCrMo WC-NiCrMo 0.6 0.6 0.6 -80 -80 -80

0.4 0.4 0.4 WC-NiCrMo -60 -60 -60 0.2 WC-NiCrCoMo 0.2 0.2 WC-FeCoNi -40 -40 -40

E vs SCE / V E vs 0.0 SCE / V E vs 0.0 SCE / V E vs 0.0 WC-NiCrCoMo WC-Co -0.2 WC-Co -0.2 -0.2 -20 -20 -20 WC-FeCoNi WC-NiCrCoMo WC-Co / degrees phase angle -0.4 -0.4 -0.4 WC-FeCoNi 0 0 0 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1-1 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 10-2 10-1 1 10 102 103 104 105 10-2 10-1 1 10 102 103 104 105 10-2 10-1 1 10 102 103 104 105 i / A cm-2 i / A cm-2 i / A cm-2 freq. / Hz freq. / Hz freq. / Hz

Fig. 10 Current-potential curves (anodic sweeps) after 1 h of immersion in 0.5 M NaCl at RT, 60°C and 90°C [4] Fig. 11 Bode plots of the impedance measured after 1 h of immersion in 0.5 M NaCl at RT, 60°C and 90°C [4]

Greater amount of dissolution of 120 1.0 |Z| (Ω cm2) • a) b) 0.005Hz the binder phase in acid solution Corrosion front depth Linear fit 0.9 20°C 60°C 90°C 100 eventually results in the forma- Corrosion rate 0.8 tion of the oxide layer of W and a WC-Co 2756 912 788 0.7 region depleted in Co, compared 80 0.6 WC-FeCoNi 1782 814 506* with exposure to neutral and basic WC-NiCrCoMo 45712 22874 841* solutions. 3d 60 0.5 0.4 WC-NiCrMo 45139 52518 9227 Considering the contact loading 40 0.3 conditions involved in some industrial

Table 5 Low-frequency impedance (5 mHz) after 1 h of immersion in 0.5 M NaCl 0.2 (mm/yr) rate Corrosion applications (e.g. oil and gas extrac- 20

at RT, 60°C and 90°C (*|Z| at 10 mHz) [4] depth (μm) front Corrosion tion, underground/surface mining and 0.1 rock drilling), numerous investiga- 0 0.0 0 2 4 6 8 10 12 tions have attempted to simulate this 11d The samples of WC-Co and The presented results empha- type of service condition. All of these Corrosion time (d) WC-FeCoNi presented similar sised the importance of tempera- investigations have revealed a mechani- Fig. 12 a) Cross-section images illustrating microscopic aspect of corroded layer, b) average corrosion front depth and and low impedance that slightly ture when testing this type of cally unsupported, contiguous and corrosion rate as a function of exposure time [5] decreased with increasing tempera- material. Although the relative binderless/porous carbide network ture. At RT, WC-NiCrCoMo and ranking of the samples was main- after corrosive exposure, leading WC-NiCrMo showed high and very tained throughout the temperature to a damage scenario that includes similar impedance values. At 60°C, range, their corrosion resistance cracking, fragmentation and easy the impedance of WC-NiCrCoMo decreased. This means that the removal of WC grains under contact Different levels of corrosion Fig. 12b shows the measured other hand, clear corrosion effects dropped to around half of its RT service life, predicted from room loading. damage were induced in a corrosion front depth and corrosion are discerned in terms of a lower value, while practically no changes temperature measurements, can At relatively higher length scales, controlled manner through the rate as a function of corrosion time. load-bearing capacity (i.e. larger were observed for WC-NiCrMo. be significantly reduced at higher testing protocols based on Hert- simple immersion of specimens The linear correlation between residual indentation depth) for the At 90°C, the impedance of WC-NiCr- temperatures. zian theory have also proven to be in stirred 0.1 M HCl solution corrosion front depth and corrosion corroded materials. Under the CoMo dropped to values close to successful in assessing contact at room temperature. Weight time is in agreement with the experimental conditions studied, those of WC-Co and WC-FeCoNi. damage. By analysing the corre- loss was measured during the relatively constant corrosion rate the reduction in the mechanical Corrosion effects on WC-NiCrMo showed a smaller drop, sponding indentation stress-strain immersion tests. Corrosion rate determined (using weight loss data) response increases for longer remaining the most corrosion- contact damage of a WC-Ni curves, deformation and fracture mech- was determined according to the under the given test condition. corrosion times, reflected in the resistant composite. The results cemented carbide anisms, such studies have revealed a following equation: Fig. 13 shows the residual increased residual depth with the clearly demonstrate that tempera- clear microstructure-damage toler- indentation depth as a function increasing corrosion time at each ture affects the response of these Finally, Y F Zheng, G Fargas, ance interaction in cemented carbides. of applied load for all of the specific loading condition. When composites, with a decrease in E Roitero and L Llanes (Universitat However, all of these studies have 87.6 t conditions studied. As expected, the thickness of the corroded layer Politecnica de Catalunya, Spain) and 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 𝑤𝑤𝑤𝑤 corrosion resistance as temperature limited their scope to the testing of 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 𝐶𝐶𝐶𝐶𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟 � � = � � the irreversible deformation is relatively small (short corrosion rises. O Lavigne (Hyperion Materials and pristine or virgin hardmetals. Hence, 𝑦𝑦𝑦𝑦𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟 𝐴𝐴𝐴𝐴ρ becomes more pronounced as time), indentation damage is Visual inspection corroborated Technologies, Spain), reported the information on how contact response where w is the weight loss in indentation load increases. On the controlled by the deformation of the results obtained by electro- results of their study of the corro- may be affected by the damage induced mg; A is the surface area of the chemical testing. Both WC-Co and sion effects on contact damage of a by corrosion is completely missing. specimen in cm2; ρ is the density of WC-FeCoNi showed clear evidence WC-Ni cemented carbide [5]. Within this context, it was the aim the material in g/cm3 and t is the of corrosion at all temperatures. The The corrosion behaviour of of the reported study to assess and corrosion time in hours. 28 corrosion was more uniform in the hardmetals has been extensively analyse surface and mechanical contact Hertzian tests were conducted 26 case of the standard WC-Co, while, investigated in recent decades, response changes induced by exposure in a servohydraulic testing machine focusing on the influence of multiple in WC-FeCoNi, it was more localised to an acidic medium of a hardmetal using hardmetal indenters with 24 in the form of pitting. This follows factors, such as surface state, grade. The study was conducted by a curvature radius (R) of 2.5 mm. the same behaviour as observed corrosive medium, microstructural implementing Hertzian indentation Monotonic loading was conducted 22 in previous studies by the group assemblage and binder chemical tests, complemented with the use of following a trapezoidal waveform 20 0 d and suggests that the increase of nature. In these studies, it has been laser scanning confocal microscopy at a loading rate of 30 N s-1 and 3 d temperature does not change the shown that: (LSCM). applying the full test force for 20 s. 18 7 d type of attack. WC-NiCrCoMo did not A medium grain sized Ni-based Fig. 12a shows cross-sectional 11 d • Metallic binders are prefer- Residual depth (μm) 0 d show corrosion attack at RT or 60°C, hardmetal grade, supplied by Hype- micrographs for the studied 16 entially attacked in acidic and 3 d but some pitting and interstitial rion Materials and Technologies, was hardmetal grade corroded for three neutral environments, while 14 7 d corrosion seemed to have occurred investigated. Binder content and mean and eleven days, respectively. These the ceramic phase is the one 11 d at 90°C. Unlike all other samples, carbide grain size were 6 wt.% and reveal significant microstructural 12 corroded in alkaline solution WC-NiCrMo did not reveal any signs about 1.3 μm, respectively, the latter changes uniformly distributed in 1500 2000 2500 3000 3500 4000 of corrosion throughout the whole • Corrosion-induced damage by being measured by the linear intercept the subsurface regions. Longer Indentation load (N) temperature range, confirming its acidic media is usually much method using Field Emission Scanning immersion times generate more greater corrosion resistance among more pronounced than that of Electron Microscopy (FESEM) micro- relevant changes in microstructure Fig. 13 Indentation depth as a function of applied load for uncorroded and all of the tested samples. neutral and basic ones graphs. as well as deeper corrosion fronts. corroded specimens [5]

Load (N) Contact damage in the pristine for ring cracking and the fracture Author and contacts to High Temperature, by F De Luca, 1000 1500 2000 2500 3000 3500 4000 hardmetal evolves from an initial toughness of the material are quad- H Zhang, K Mingard, M Stewart, B partial ring crack, which develops ratically related and should then be M Jablon, C Trager-Cowan, and M G Dr David Whittaker 0 into a full ring crack as indentation closely linked to the volume fraction Gee, published in Materialia, 2020, Tel: +44 1902 338498 load increases (Fig. 14). At load of the binder phase. After expo- 12, p.100713. 3 [email protected] levels higher than 2250 N, well sure to acidic media, the degraded [4] The influence of temperature 7 [1] Bruno Guimarães, University of above the plastic yielding onset of microstructure consists of a loose on the corrosion resistance of the investigated grade, the tensile and porous/binderless WC skeleton. Minho, Portugal

Corrosion time (d) Corrosion 11 hardmetals, A M Ferro Rocha, Pedro brunopereiraguimaraes@hotmail. radial stresses and strains existing Hence, effective removal of the Silva, A M R Senos, A C Bastos, F in the vicinity of the residual ductile metallic phase implies that com Fig. 14 Damage evolution diagram as a function of indentation load and Rodrigues and J Sacramento. As imprints become large enough to the well-established ligament-rein- corrosion time [5] [2] Francois De Luca, National presented at the Euro PM2020 Virtual induce circumferential cracks at forcement mechanism in cemented Physical Laboratory, UK Congress, October 5–7, 2020, and the surface of the pristine spec- carbides is no longer operative [email protected] published in the proceedings by the imen. In the current study, under and, thus, the energy required for [4] Alexandre Ferro Rocha, Univer- European Powder Metallurgy Asso- the uncorroded substrate beneath by means of LSCM. The gathered the experimental load conditions crack emergence and extension is sity of Aveiro, Portugal ciation (EPMA) the degraded surface. However, information is summarised in Fig. investigated (up to 4000 N), no lowered. [email protected] [5] Corrosion effects on contact for longer exposure times, damage 14. After being corroded, damage radial cracks outside the imprint On the other hand, as discussed damage of a WC-Ni cemented tends to be confined to the corroded tolerance to mechanical contact are discerned in the uncorroded previously, the load-bearing [5] Yafeng Zheng, Universitat carbide, Y F Zheng, G Fargas, E layer, resulting from the gradual of the studied hardmetal grade is condition. capacity of the studied hardmetal Politecnica de Catalunya, Spain Roitero, L Llanes and O Lavigne. As weakening of the ‘substrate effect’. significantly lessened. This state- Meanwhile, radial cracks and grade depends significantly on the [email protected] presented at the Euro PM2020 Virtual Hertzian contact tests were ment is based on two experimental even specimen breakage were thickness of the corroded layer. With Congress, October 5–7, 2020, and conducted on uncorroded and facts: observed as additional damage a thin corroded layer (three days of Euro PM2020 Proceedings published in the proceedings by the corroded specimen surfaces to features/scenarios under the given exposure), the whole plastic defor- • Reduced critical load (Pc) for European Powder Metallurgy Asso- discern the difference in their loading conditions in the corroded mation was mainly controlled by the the generation of incipient ciation (EPMA) response to indentation damage. specimens. In these samples, the deformation of the ‘substrate’ linked The full proceedings of the Euro cracks With reference to the evolution critical load to produce (partial/ to the uncorroded hardmetal. This PM2020 Virtual Congress are available to purchase from the of surface damage from inelastic • More severe damage evolution full) ring and radial cracks is reflected in the small changes in Euro PM2021 deformation to fracture, critical scenario involving radial cracks decreases as the corrosion time the critical load for the generation European Powder Metallurgy loads associated with different and even specimen breakage increases (Fig. 14). As reported of the incipient cracks at relatively Association. The Euro PM2021 Virtual Congress events were determined visually as the applied load increases. in the literature, the critical load short exposure times (Fig. 14). www.epma.com & Exhibition will be held online As the thickness of the corroded from October 18–22, 2021. Planned layer increases, the deformation References presentations will be prerecorded tends to be confined to the corroded and available for the duration of the layer, implying that the corre- [1] The effect of surface texturing event. Papers will be published as sponding deformation and damage on the temperature distribu- usual and the proceedings will be scenario are close to the mechan- tion on WC-Co cutting tools, B available for sale in October. ical response of the remaining bind- Guimarães, F S Silva, G Miranda, erless WC skeleton. Considering the C M Fernandes and D Figue- loose and porous WC skeletons left iredo. As presented at the Euro after the binder is leached away, the PM2020 Virtual Congress, October shear stress during the unloading 5–7, 2020, and published in the may be more likely to cause the proceedings by the European initiation of radial cracks around the Powder Metallurgy Association edge of the plastic zone. Residual (EPMA) (effective) porosity, after the binder has been leached away, acts not [2] High temperature nanome- only as an array of many small chanical behaviour of WC grains stress concentrators, but also as in WC-Co hardmetals, F De Luca, crack precursors. H Zhang, V Tong and K Mingard. In general, for ceramic mate- As presented at the Euro PM2020 rials, the formation of radial cracks Virtual Congress, October 5–7, signifies the end of the service 2020, and published in the life of engineering components. proceedings by the European Therefore, it may be stated that Powder Metallurgy Association premature failure will appear during (EPMA) Fig. 15 Damage features induced by spherical indentation under different corrosion and loading conditions: a) 0d-1500N, the service of hardmetal tools and [3] Nanomechanical Behaviour b) 0d-2500N, c) 0d-3000N, d) 0d-4000N, e) 7d-3000N and f) 7d-3500N. All the images show different representative components involving corrosion and of Individual Phases in WC-Co scenarios, corresponding to the symbols used in Fig. 14 [5] impact loading conditions. Cemented Carbides, from Ambient

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