High Strength X3nicomoti 18-9-5 Maraging Steel Prepared by Selective Laser Melting from Atomized Powder

Total Page:16

File Type:pdf, Size:1020Kb

High Strength X3nicomoti 18-9-5 Maraging Steel Prepared by Selective Laser Melting from Atomized Powder materials Article High Strength X3NiCoMoTi 18-9-5 Maraging Steel Prepared by Selective Laser Melting from Atomized Powder Angelina Strakosova *, Jiˇrí Kubásek, Alena Michalcová, Filip Pr ˚uša,Dalibor Vojtˇechand Drahomír Dvorský Department of Metals and Corrosion Engineering, Faculty of Chemical Technology, University of Chemistry and Technology, Technická 5, Praha 6—Dejvice, 166 28 Prague, Czech Republic; [email protected] (J.K.); [email protected] (A.M.); [email protected] (F.P.); [email protected] (D.V.); [email protected] (D.D.) * Correspondence: [email protected] Received: 21 November 2019; Accepted: 10 December 2019; Published: 12 December 2019 Abstract: Maraging steels are generally characterized by excellent mechanical properties, which make them ideal for various industrial applications. The application field can be further extended by using selective laser melting (SLM) for additive manufacturing of shape complicated products. However, the final mechanical properties are strongly related to the microstructure conditions. The present work studies the effect of heat treatment on the microstructure and mechanical properties of 3D printed samples prepared from powder of high-strength X3NiCoMoTi 18-9-5 maraging steel. It was found that the as-printed material had quite low mechanical properties. After sufficient heat treatment, the hardness of the material increased from 350 to 620 HV0.1 and the tensile yield strength increased from 1000 MPa up to 2000 MPa. In addition, 3% ductility was maintained. This behavior was primarily affected by strong precipitation during processing. Keywords: maraging steel; atomized powder; selective laser melting; heat treatment; precipitation hardening 1. Introduction Selective laser melting (SLM) is one of the best-known methods of additive production of materials. In everyday life, the most commonly encountered name for this method is 3D printing [1]. The aim of this method is to produce a three-dimensional metal part. The principle of manufacturing these parts lies in the use of a laser for melting metallic powders and subsequent layer-by-layer application of these powders. Due to the high cooling rate, rapid solidification and material transformations occur in the material. The advantage of this method is that the product is already made into the desired shape and size without the necessity for secondary machining [1]. The most useful applications of SLM technology are found in medicine, aviation, the automotive industry, and also in the work of architects [2]. The main advantages of 3D printing over conventional methods of manufacturing metallic materials are as follows. First, it provides the ability to produce components with various complex surface and volume shapes. This means that details can be produced during a single operation. Secondly, it requires minimal surface machining of the finished product and thus minimizes waste [1]. Third, SLM technology allows us to work with a wide range of materials. The most extensively studied are steels, Al alloys, Ti alloys, and Ni superalloys [1,3]. The microstructure of 3D printed material is almost non-porous, reaching up to 99.9% of theoretical density [1]. It is also very different from the microstructure of the materials produced by other methods. Thanks to the high cooling rate and Materials 2019, 12, 4174; doi:10.3390/ma12244174 www.mdpi.com/journal/materials Materials 2019, 12, 4174 2 of 10 Materials 2019, 12, x FOR PEER REVIEW 2 of 10 solidification of the alloy during the SLM process, we get a material with a very fine-grained cell microstructure.microstructure. Grain Grain size size reduction reduction has has a a beneficial beneficial effect effect on on the the mechanical mechanical properties properties of of 3D 3D printed printed productsproducts [4–8]. [4–8]. MaragingMaraging steels steels are are widely widely used used in in the the aerospace aerospace in industry.dustry. Also, Also, they they are are widely widely used used in in tooling tooling applicationsapplications and and in in the the production production of ofweapons. weapons. Maraging Maraging steels steels are also are well-known also well-known thanks thanks to their to excellenttheir excellent mechanical mechanical properties. properties. The Themost most import importantant properties properties are are very very high high hardness, hardness, good good weldability,weldability, high high ductility, ductility, and easy machinability after solution annealing. Spatial Spatial stability stability during during agingaging is is one one more more positive positive feature feature of of the the maragi maragingng steels steels [8–13]. [8–13]. Their Their properties properties and and range range of of applicationsapplications are are one one of of the the reasons reasons for for the the interest interest in in their their production production by by using using modern modern technologies, technologies, includingincluding 3D 3D printing. printing. MaragingMaraging steelssteels exertexert these these very very good good mechanical mechanic propertiesal properties after theafter application the application of heat treatment of heat treatmentinvolving involving solution annealing solution annealing and aging. and The aging. first stateThe first after state quenching after quenching is the martensitic is the martensitic structure structureof the material. of the material. This structure This structure may be causedmay be by ca diusedfferent by different means. Inmeans. maraging In maraging steels, the steels, creation the creationof martensite of martensite is supported is supported by the highby the Ni high content Ni co inntent an alloy.in an Inalloy. contrast In contrast to this, to in this, other in steels,other steels,the martensitic the martensitic structure structure is due tois due a relatively to a relati highvely carbon high content.carbon content. Aging at Aging a temperature at a temperature between between480 ◦C to 480 510 °C◦C to causes 510 °C intermetallic causes intermetallic precipitation precip [13itation,14]. Several [13,14]. phases Several were phases identified were identified in maraging in maragingsteels like steels Ni3(Ti, like Mo) Ni3(Ti, [13], Mo) Ni3 [13],X (X Ni= 3Ti,X (X Al, = Ti, Mo) Al, [10 Mo)], (Fe, [10], Ni, (Fe, Co) Ni,3 (Ti,Co)3 Mo),(Ti, Mo), (Fe, (Fe, Ni, Co)Ni, Co)3(Mo,3(Mo, Ti), Ti),and and (Fe, (Fe, Ni, Ni, Co) Co)7Mo7Mo6 [156 [15].]. SeveralSeveral major major works works have have been been carried carried out out to to get get a a better better idea idea of of the the prop propertieserties of of X3NiCoMoTi X3NiCoMoTi 18-9-518-9-5 maraging maraging steel steel made made by by 3D 3D printing. printing. Kempen Kempen et et al. al. [1] [1] investigated investigated how how impact impact and and tensile tensile propertiesproperties depend depend on on aging aging treatment treatment and and process process parameters. parameters. Tensile, Tensile, fracture, fracture, and and fatigue fatigue crack crack growthgrowth of of maraging maraging steel steel was was st studiedudied by by Suryawanshi Suryawanshi et et al. al. [4]. [4]. Some Some researchers researchers [7,16] [7,16] have have investigatedinvestigated the the effect effect ofof didifferentfferent heatheat treatments treatments on on microstructure microstructure and and mechanical mechanical properties. properties. In In all allthe the work work mentioned mentioned above, above, the the aging aging treatment treatment significantly significantly improvedimproved thethe properties due to to the the formationformation of of precipitates. precipitates. However, However, only only limited limited information information is is known known about about the the precipitates precipitates which which formform during during the the treatment treatment of of 3D 3D printed printed steel. steel. For For example, example, the the formation formation of of a a Ni3X Ni3X (X (X == Ti,Ti, Al, Al, Mo) Mo) precipitatesprecipitates after after heat heat treatment treatment wa wass described described by references [10,15]. [10,15]. TheThe aim ofof thisthis work work is tois investigateto investigate the impactthe impact of the of 3D the printing 3D printing process process and two and heat two treatment heat treatmentmodes on modes microstructure on microstructure and mechanical and mechanical properties properties X3NiCoMoTi X3NiCoMoTi 18-9-5 maraging 18-9-5 steel.maraging steel. 2.2. Materials Materials and and Methods Methods SamplesSamples in in the the shape shape of of a a dog dog bone bone (Figure (Figure 1.)1) werewere producedproduced byby 3D3D printingprinting on SLM solution 280HL280HL (NETME Center,Center, Brno, Brno, Czech Czech Republic) Republic) from from the powder the powder X3NiCoMoTi X3NiCoMoTi 18-9-5 alloy.18-9-5 The alloy. chemical The chemicalcomposition composition (Table1) was(Table found 1) was using found XRF usin analysisg XRF on analysis spectrometer on spectrometer ARL 9400. ARL 9400. Figure 1. Dimensions of 3D-printed sample for a tensile test. Figure 1. Dimensions of 3D-printed sample for a tensile test. Table 1. Chemical composition of X3NiCoMoTi 18-9-5 maraging steel. Table 1. Chemical composition of X3NiCoMoTi 18-9-5 maraging steel. Element Ni Co Mo Ti C Al Cr Mn Si Fe Element Wt/%Ni 19Co 9.3Mo 5 0.64Ti 0.03C 0.06Al 0.08Cr 0.04 Mn 0.07 Bal.Si Fe Wt/% 19 9.3 5 0.64 ≤≤0.03 0.06 0.08 0.04 0.07 Bal. The powder morphology structure and size distribution are shown in Figure 2. Particle size analysis was performed using a scanning electron microscope (TESCAN VEGA 3 LMU, Brno, Czech Republic) and the ImageJ program. Materials 2019, 12, 4174 3 of 10 The powder morphology structure and size distribution are shown in Figure2. Particle size analysis was performed using a scanning electron microscope (TESCAN VEGA 3 LMU, Brno, Czech Republic) and theMaterials ImageJ 2019, 12 program., x FOR PEER REVIEW 3 of 10 b) 65 60 55 50 45 40 35 30 Count 25 20 15 10 5 0 0 5 10 15 20 25 30 35 40 45 50 55 Diameter, µm Figure 2.
Recommended publications
  • A New Maraging Stainless Steel with Excellent Strength–Toughness–Corrosion Synergy
    materials Article A New Maraging Stainless Steel with Excellent Strength–Toughness–Corrosion Synergy Jialong Tian 1,2, Wei Wang 2,*, M. Babar Shahzad 2, Wei Yan 2, Yiyin Shan 2, Zhouhua Jiang 3 and Ke Yang 2 1 School of Materials Science and Engineering, Northeastern University, Shenyang 110004, China; [email protected] 2 Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China; [email protected] (M.B.S.); [email protected] (W.Y.); [email protected] (Y.S.); [email protected] (K.Y.) 3 School of Metallurgy, Northeastern University, Shenyang 110004, China; [email protected] * Correspondence: [email protected]; Tel.: +86-24-8397-8745 Received: 17 October 2017; Accepted: 8 November 2017; Published: 10 November 2017 Abstract: A new maraging stainless steel with superior strength–toughness–corrosion synergy has been developed based on an innovative concept of alloy design. The high strength–toughness combination is achieved by forming dispersive nano-sized intermetallic compounds in the soft lath martensitic matrix with a slight amount of residual austenite. The good corrosion resistance is guaranteed by exactly controlling the Co content based on understanding the synergistic effect between Co and Cr. The fine structure characteristics of two dominant strengthening precipitations including Ni3Ti and Mo-rich phases were finely characterized associated with transmission electron microscope (TEM) and atom probe tomography (APT) analyses. The relationship among microstructure, strength and toughness is discussed. The precipitation mechanism of different precipitates in the new maraging stainless steel is revealed based on the APT analysis. Keywords: maraging stainless steel; alloy design; strength and toughness; corrosion resistance; atomic probe tomography; precipitation mechanism 1.
    [Show full text]
  • Improvement in Mechanical Properties of C300 Maraging Steel by Application of VAR Process
    ARTICLE IN PRESS Vacuum 82 (2008) 521–528 www.elsevier.com/locate/vacuum Improvement in mechanical properties of C300 maraging steel by application of VAR process Seyed Reza Elmi HoseiniÃ, Hosein Arabi, Hekmat Razavizadeh Department of Metallurgy and Materials Engineering, Iran University of Science and Technology, Narmak, Tehran, Iran Received 22 November 2006; received in revised form 1 August 2007; accepted 11 August 2007 Abstract The prime objective of this research was to improve the mechanical properties of C300 maraging steels originally cast in the vaccum induction melting (VIM) and AIM furnaces by application of vaccum arc remelting (VAR) process. For this purpose two sets of C300 maraging steel with different amounts of Ti were cast in two different types of furnaces. Three bars with 1, 1.5 and 2 wt% of Ti were produced in the argon induction melting (AIM) furnace and two bars with 0.65 and 1 wt% Ti in the VIM furnace. Then all of the bars were subjected to VAR process in order to study the effects of this process on the reduction of N and O gases and inclusions, hence improvement in the mechanical properties. The results show that the total reduction of N and O gases in the bars cast in the AIM furnace was up to 40%, the amounts of inclusions irrespective of their kind reduced up to 30% while ductility and impact energy increased up to 40%. However, these parameters in the bars cast in the VIM furnace changed as follows: total gas reduction decreased by 12%, ductility and impact energy increased by 30% and 47%, respectively.
    [Show full text]
  • Structure/Property Relationships in Irons and Steels Bruce L
    Copyright © 1998 ASM International® Metals Handbook Desk Edition, Second Edition All rights reserved. J.R. Davis, Editor, p 153-173 www.asminternational.org Structure/Property Relationships in Irons and Steels Bruce L. Bramfitt, Homer Research Laboratories, Bethlehem Steel Corporation Basis of Material Selection ............................................... 153 Role of Microstructure .................................................. 155 Ferrite ............................................................. 156 Pearlite ............................................................ 158 Ferrite-Pearl ite ....................................................... 160 Bainite ............................................................ 162 Martensite .................................... ...................... 164 Austenite ........................................................... 169 Ferrite-Cementite ..................................................... 170 Ferrite-Martensite .................................................... 171 Ferrite-Austenite ..................................................... 171 Graphite ........................................................... 172 Cementite .......................................................... 172 This Section was adapted from Materials 5election and Design, Volume 20, ASM Handbook, 1997, pages 357-382. Additional information can also be found in the Sections on cast irons and steels which immediately follow in this Handbook and by consulting the index. THE PROPERTIES of irons and steels
    [Show full text]
  • Materials Technology – Placement
    MATERIAL TECHNOLOGY 01. An eutectoid steel consists of A. Wholly pearlite B. Pearlite and ferrite C. Wholly austenite D. Pearlite and cementite ANSWER: A 02. Iron-carbon alloys containing 1.7 to 4.3% carbon are known as A. Eutectic cast irons B. Hypo-eutectic cast irons C. Hyper-eutectic cast irons D. Eutectoid cast irons ANSWER: B 03. The hardness of steel increases if it contains A. Pearlite B. Ferrite C. Cementite D. Martensite ANSWER: C 04. Pearlite is a combination of A. Ferrite and cementite B. Ferrite and austenite C. Ferrite and iron graphite D. Pearlite and ferrite ANSWER: A 05. Austenite is a combination of A. Ferrite and cementite B. Cementite and gamma iron C. Ferrite and austenite D. Pearlite and ferrite ANSWER: B 06. Maximum percentage of carbon in ferrite is A. 0.025% B. 0.06% C. 0.1% D. 0.25% ANSWER: A 07. Maximum percentage of carbon in austenite is A. 0.025% B. 0.8% 1 C. 1.25% D. 1.7% ANSWER: D 08. Pure iron is the structure of A. Ferrite B. Pearlite C. Austenite D. Ferrite and pearlite ANSWER: A 09. Austenite phase in Iron-Carbon equilibrium diagram _______ A. Is face centered cubic structure B. Has magnetic phase C. Exists below 727o C D. Has body centered cubic structure ANSWER: A 10. What is the crystal structure of Alpha-ferrite? A. Body centered cubic structure B. Face centered cubic structure C. Orthorhombic crystal structure D. Tetragonal crystal structure ANSWER: A 11. In Iron-Carbon equilibrium diagram, at which temperature cementite changes fromferromagnetic to paramagnetic character? A.
    [Show full text]
  • High Performance Steel for Percussive Drilling
    TVE-K 17001 Examensarbete 15 hp 2 Juni 2017 High Performance Steel for Percussive Drilling Elin Åkerlund Jakob Jonsson Åberg Patrik Österberg Rebecka Havo Mikael Fredriksson Abstract High Performance Steel for Percussive Drilling Elin Åkerlund, Jakob Jonsson Åberg, Patrik Österberg, Rebecka Havo and Mikael Fredriksson Teknisk- naturvetenskaplig fakultet UTH-enheten Atlas Copco Secoroc AB are searching after new bulk materials for drill heads that are used in percussive drilling in order to improve their strength and durability. The Besöksadress: aim of this project is to assist Atlas Copco in this search and provide them with Ångströmlaboratoriet Lägerhyddsvägen 1 further information regarding material properties, alloying elements, suppliers, etc. Hus 4, Plan 0 A literary study was carried out in order to identify materials that had UTS and KIC Postadress: more than or equal to 1700 MPa and 70 MPa*m^1/2, respectively. Materials that Box 536 751 21 Uppsala fulfilled these criteria were T250 grade maraging steel, Cobalt free maraging steel, High cobalt maraging steel, 300 grade maraging steel, AerMet 100, AF1410, S53, Telefon: M54, 300M, 4340M and PremoMet. These were categorized into maraging steels, 018 – 471 30 03 high alloy secondary hardened steels, and low alloy steels, and were then further Telefax: researched. 018 – 471 30 00 The material with the highest combination of UTS and KIC was M54 followed by Hemsida: AerMet 100; while AF1410 had the highest KIC but a low UTS, and PremoMet had http://www.teknat.uu.se/student the highest UTS but a low KIC. Maraging steels and HASH steels have a similar price range, while low alloy steels are much cheaper.
    [Show full text]
  • A Review of Factors Affecting the Mechanical Properties of Maraging
    metals Review AReview Review of Factors Affecting the Mechanical PropertiesA Review ofof MaragingFactors Affecting Steel 300 the Fabricated Mechanical via Laser PowderProperties Bed of Fusion Maraging Steel 300 Fabricated via Laser Powder Bed Fusion Barry Mooney and Kyriakos I. Kourousis * Barry Mooney and Kyriakos I. Kourousis * School of Engineering, University of Limerick, V94 T9PX Limerick, Ireland * SchoolCorrespondence: of Engineering, [email protected]; University of Limerick, Tel.: V94+353-61202217 T9PX Limerick, Ireland * Correspondence: [email protected]; Tel.: +353-61202217 Received: 29 August 2020; Accepted: 20 September 2020; Published: 22 September 2020 Received: 29 August 2020; Accepted: 20 September 2020; Published: 22 September 2020 Abstract: Maraging steel is an engineering alloy which has been widely employed in metal additive Abstract: Maraging steel is an engineering alloy which has been widely employed in metal additive manufacturing. This paper examines manufacturing and post-processing factors affecting the manufacturing. This paper examines manufacturing and post-processing factors affecting the properties of maraging steel fabricated via laser powder bed fusion (L-PBF). It covers the review of properties of maraging steel fabricated via laser powder bed fusion (L-PBF). It covers the review of published research findings on how powder quality feedstock, processing parameters, laser scan published research findings on how powder quality feedstock, processing parameters, laser scan strategy, build orientation and heat treatment can influence the microstructure, density and porosity, strategy, build orientation and heat treatment can influence the microstructure, density and defects and residual stresses developed on L-PBF maraging steel, with a focus on the maraging steel porosity, defects and residual stresses developed on L-PBF maraging steel, with a focus on the 300 alloy.
    [Show full text]
  • Microstructural Analysis of Co-Free Maraging Steel Aged Aline Castilho Rodrigues1, Heide Heloise Bernardi1, Jorge Otubo2
    doi: 10.5028/jatm.v6i4.400 Microstructural Analysis of Co-Free Maraging Steel Aged Aline Castilho Rodrigues1, Heide Heloise Bernardi1, Jorge Otubo2 ABSTRACT: Maraging steels have low carbon content and are highly alloyed, having as main feature the ability to increase INTRODUCTION the mechanical strength after thermal aging. Therefore, the objective of this work is to analyze the effect of aging in a Co- Maraging steel was developed in the 1950’s, to support free maraging steel, Fe – 0.014% C – 0.3% Mn – 3.9% Mo – 2.1% Cu – 0.19% Si – 11.8% Cr – 9.1% Ni – 1.0% Ti (wt), at the demand for a low density and temperature resistant steel different heat treatment times (10 min - 960 min) at constant (250°C – 300°C), for improving aircraft performance. This new temperature (550°C), after cold rolling up to 66% and 77% material was created adding aluminum (Al) and titanium (Ti) in area reduction. Microstructures were analyzed by scanning steel with nickel (Ni). In the 1960’s, cobalt (Co) and molybdenum electron microscopy (SEM - EDS) and mechanical properties by Vickers hardness measurements. The results showed (Mo) were added into the composition of maraging steels. a significant increase in the hardness of the material after Clarence George Bieber, in International Nickey Company, aging heat treatment on the solution treated and deformed studied the addition of these elements in the alloy and concluded samples. The aging heat treatment which was harder about 650 HV was 550°C/60 min. that there is a significant increasing in mechanical resistance (Lopes, 2007; Méndez, 2000).
    [Show full text]
  • Additive Manufacturing 18 Ni Maraging Steel
    Additive Manufacturing 18 Ni Maraging Steel Designed for Processing in Laser Powder Bed Fusion (PBF-LB) Systems Applications MetcoAdd™ C300-A is an iron-nickel-cobalt based powder similar to 18 Ni ▪ Tools and dies maraging steel. The alloy chemistry is known to provide ultra high strength in ▪ Plastic injection molds combination with toughness and resistance to cracking. The composition of the ▪ Light metal and pressure die casting powder is similar to Werkstoff Nr. 1.2709 / X3NiCoMoTi 18-9-5 and AMS 6514. ▪ Cold extrusion tools Room temperature static properties of PBF-LB processed and heat treated material coupons have been shown to be comparable to those of AMS 6514. For reference purposes Oerlikon has processed MetcoAdd C300-A using fixed parameters and 40 μm layer thickness to provide data below. Additional testing has been performed by an extensive network of consortia and customer partners on a broader range of machine types. Properties may be optimized based on application specific requirements. Typical Post Heat Treatment Properties (C300-A) [1] [2] [3] Concept Laser M2 Cusing EOS M290 Test Method Ultimate Tensile Strength (MPa), XY/Z 2064±25 / 2104±15 2050±17 / 2027±9 Yield Strength (MPa), XY/Z 1982±30 / 2023±15 1996±18 / 1980±7 ASTM E8 Elongation at break %, XY/Z 5±2 / 5±3 9±1 / 8±1 Hardness (VHN300g) 594+/-15 599+/-10 ASTM E384-17 Relative Density % >99.9% >99.8% Internal Spec. [1] Disclaimer: All data published in this datasheet has been shared for reference purposes only and is not sufficient to design or certify parts.
    [Show full text]
  • Plasma Arc Remelting of Steels and Nickel-Based Superalloys N
    Plasma arc remelting of steels and nickel-based superalloys N. Sparks, J. Young, L. Shaw, Thomas Johnson To cite this version: N. Sparks, J. Young, L. Shaw, Thomas Johnson. Plasma arc remelting of steels and nickel-based superalloys. Journal de Physique IV Proceedings, EDP Sciences, 1993, 03 (C7), pp.C7-883-C7-888. 10.1051/jp4:19937137. jpa-00251757 HAL Id: jpa-00251757 https://hal.archives-ouvertes.fr/jpa-00251757 Submitted on 1 Jan 1993 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. JOURNAL DE PHYSIQUE IV Colloque C7, supplCment au Journal de Physique 111, Volume 3, novembre 1993 Plasma arc remelting of steels and nickel-based superalloys N.C. SPARKS, J.M. YOUNG, L. SHAW* and TI? JOHNSON ZRC in Materials for High Pe$ormance Applications, The University of Birmingham, Birmingham B15 2TT U.K. * special ~eltedProducts Limited, Atlas House, Atterclge Road, Shefield, S4 7W U.K. ABSTRACT. The IRC Plasma Arc Cold Hearth Remelting (PACHR) furnace has been used to produce lOOmm and 150mm diameter ingots of alloy 718, M50 bearing steel and GI 10 maraging steel from VIMIVAR feedstocks. These mals highlighted the importance of accurately controlling the level of the melt pool surface in the crucible in order to produce an acceptable ingot finish.
    [Show full text]
  • Mechanical Properties of 3D-Printed Maraging Steel Induced by Environmental Exposure
    metals Article Mechanical Properties of 3D-Printed Maraging Steel Induced by Environmental Exposure Troy Y. Ansell 1,* , Joshua P. Ricks 1, Chanman Park 1, Chris S. Tipper 2 and Claudia C. Luhrs 1 1 Mechanical and Aerospace Engineering Department, Naval Postgraduate School, Monterey, CA 93943, USA; [email protected] (J.P.R.); [email protected] (C.P.); [email protected] (C.C.L.) 2 Marine Corps Logistics Command, Marine Depot Maintenance Command, Albany, GA 31704, USA; [email protected] * Correspondence: [email protected] Received: 11 January 2020; Accepted: 31 January 2020; Published: 4 February 2020 Abstract: Changes in the mechanical properties of selective laser melted maraging steel 300 induced by exposure to a simulated marine environment were investigated. Maraging steel samples were printed in three orientations: vertical (V), 45◦ (45), and horizontal (H) relative to the print bed. These were tested as-printed or after heat-treatment (490 ◦C, 600 ◦C, or 900 ◦C). One set of specimens were exposed in a salt spray chamber for 500 h and then compared to unexposed samples. Environmental attack induced changes in the microstructural features and composition were analyzed by scanning electron microscopy and energy dispersive spectroscopy respectively. Samples printed in the H and 45◦ directions exhibited higher tensile strength than those printed in the V direction. Corrosion induced reduction in strength and hardness was more severe in specimens heat-treated between 480 ◦C and 600 ◦C versus as-printed samples. The greatest decrease in tensile strength was observed for the 45◦-printed heat-treated samples after exposure. A comparison between additive and subtractive manufactured maraging steel is presented.
    [Show full text]
  • Alloy Steelssteels High Strength Low Alloy (HSLA)
    77 AlloyAlloy SteelsSteels High strength low alloy (HSLA). a type of steel alloy that provides many benefits over regular steel alloys contain a very small percentage of carbon (less than one-tenth of a percent) and only small amounts of very specific alloying elements referred to as 'microalloyed', as they are indeed alloyed in extremely small amounts by comparison to other main commercial alloy steels group of low carbon steels that utilize small amounts of alloying elements to attain yield strengths in excess of 275 MPa in the as-rolled or normalized conditions SME 1613 : Materials Science 2007 TYPICAL CHEMICAL COMPOSITION OF HSLA SME 1613 : Materials Science 2007 MECHANICAL PROPERTIES: HSLA • Much stronger and tougher than ordinary plain carbon steels. • alloying elements : alter the microstructure of plain carbon steels, which is usually a ferrite-pearlite aggregate, to produce a very fine dispersion of alloy carbides in an almost pure ferrite. • Increases the material's strength by precipitation strengthening and by refining the grain size, which in the case of ferrite increases yield strength by 50% for every halving of the mean grain diameter. SME 1613 : Materials Science 2007 Microstructure of HSLA A517 Grade A533 grade b, quenched 7,quenched from from 900C and tempered 925°C,tempered at at 620C . This is a heavy 650C = tempered section plate, the martensite. microstructure consists of ferrite and tempered bainite. SME 1613 : Materials Science 2007 Application of HSLA • Applications: include oil and gas pipelines, automotive beams, offshore structures and shipbuilding. • Also used in cars, trucks, cranes, bridges and other structures that are designed to handle a lot of stress, often at very low temperatures.
    [Show full text]
  • Electrochemical Corrosion Characteristics of Maraging Steel Welds Depending on Chromium Content
    Int. J. Electrochem. Sci., 9 (2014) 4709 - 4720 International Journal of ELECTROCHEMICAL SCIENCE www.electrochemsci.org Electrochemical Corrosion Characteristics of Maraging Steel Welds Depending on Chromium Content S. W. Kim, H. W. Lee* Department of Materials Science and Engineering, Dong-A University, 840 Hadan-dong, Saha-gu, Busan 604-714, Republic of Korea *E-mail: [email protected] Received: 15 April 2014 / Accepted: 28 May 2014 / Published: 16 June 2014 The corrosion behavior of maraging steel weldments which depend on Cr content has been studied, and electrochemical experiments were conducted changing the immersion time in chloride solution. The study was carried out using open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy techniques. The results showed that corrosion rate decreased and Ecorr and Epit increased with increasing Cr content and also with increased with immersion time of the maraging steel before measurements. The surface morphology of the corroded samples has been examined by Scanning Electron Microscopy. It showed that the resistance to general and pitting corrosion increased as the Cr content increased. Keywords: Steel; polarization; EIS; SEM; Pitting corrosion 1. INTRODUCTION As maraging steel is comprised of low carbon (C≤0.03) Fe-Ni martensite matrix of BCC structure containing precipitation hardening alloy elements in a solid state, it is hardened by precipitation of intermetallic compounds resulting from aging at 480℃.[1] This steel of light gray color has high toughness in spite of its high strength. Many applications of maraging steels in aerospace, marine, and nuclear power fields as well as for special parts of industrial machines have been realized due to their unique combination of superior mechanical properties, fabrication, weldability and corrosion resistance.
    [Show full text]