DOCSLIB.ORG

Ampco Alloy Brochure.Pdf

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ampco Alloy Brochure.Pdf COMMITTED TO INNOVATIVE PRODUCTS AND SUPERIOR CUSTOMER SERVICE FOR OVER 90 YEARS. Ampco Metal is an integrated metal producer, offering under the Ampco® and Ampcoloy® brands the widest range of premium speciality bronzes and copper alloys, famous for their exceptional physical and mechanical properties. Professional value-added services, exceptional product quality and short delivery times are internationally guaranteed from our warehouses in Europe, USA and China. Round bar, rectangles, tubes and plate are all readily available from stock and cast or forged shapes can be produced specifically to your requirements. In addition to our activity in alloys, Ampco Metal has invested extensively in the latest machining technology and has the expertise to deliver highly competitive, pre-machined or fully-machined precision pieces, as required. EUROPE (International Headquarters) : Ampco Metal S.A. Route de Chésalles 48 1723 Marly 1 SWITZERLAND Tel.: +41 26 439 93 10 Fax: +41 26 439 93 01 AMPCO METAL YOUR SOLUTION PROVIDER COPPER-BASED ALLOY SOLUTIONS USA : Ampco Metal Inc. 1117 East Algonquin Road Arlington Heights 60005, Illinois FULL PRODUCT RANGE USA Tel.: + 1 800 844 6008 WORLDWIDE AVAILABILITY Fax: + 1 847 437 6008 EXPERT ADVICE ASIA : Ampco Metal (Foshan) Co.Ltd. Warehouse 3-A, No 9 Xinyue Road Jinqiao Industrial city, Wusha Daliang Town, Shunde, Foshan Guangdong Province, P.R. China P.C. 528333 Tel.: + 86 (0) 757 2232 6571 Fax: + 86 (0) 757 2232 6570 In addition to the above, Ampco Metal has www.ampcometal.com an extensive network of manufacturing, distribution and commercial facilities [email protected] throughout Europe, the USA and China. Please consult www.ampcometal.com for your nearest Ampco Metal outlet. www.ampcometal.com PRODUCT OVERVIEW PRODUCT OVERVIEW YOUR BEST SOURCE FOR PREMIUM COPPER ALLOYS AMPCO METAL – The first name for premium copper alloy solutions As one of the world’s leading providers of innovative The continuous development of Ampco Metal alloys Ampco Metal alloys combine proprietary metallurgical copper-based alloy solutions, Ampco Metal is an and our licensed products, together with our patented controls and thermal treatments to provide the ultimate international company with production capabilities production techniques and extensive machining in performance and dependability, with exceptional and essential stockholding throughout Europe, facilities, have resulted in our being able to offer the physical and mechanical properties produced through USA and China. widest spectrum of metal solutions and services. strictly controlled manufacturing and laboratory procedures. Since the foundation of the Company in 1914, Our technical understanding means that Ampco Ampco Metal has dedicated itself to providing alloys can be tailored to fulfill specific customer The resulting alloys offer our customers a range of complete customer satisfaction, through its requirements. Only Ampco Metal has the precise products that stand ready to serve existing markets exceptional service levels and by supplying our engineering and metallurgical expertise to provide – exceeding the requirements of the industry’s most customers with their precise copper alloy needs. true solutions to your application needs. demanding applications, yet ready to meet the challenges of new and developing market sectors. By selecting Ampco alloys* over commercial bronzes, We offer the broadest range of material forms: you can achieve: • Continuous Cast Rod, Bar, Tube • 20 – 40% higher wear resistance due to • Extruded Rod, Bar, Tube higher mechanical properties • Trouble-free operations as no nickel contamination • Forgings • 30 – 50% greater resistance to corrosion • Plate • Welding Wires These factors can result in greater component life • Fully Machined Parts and lower maintenance downtime expenditure. * Please ask your local Ampco Metal office for advice on our best alloy for your application. 2 ASK US ABOUT CUSTOM ENGINEERED ALLOYS - [email protected] PRODUCT OVERVIEW PRODUCT OVERVIEW PRODUCT OVERVIEW PRODUCT OVERVIEW Aluminium Bronzes Manganese Bronze Alloys Nickel-Aluminium Bronzes Ampco 8 Ampco 21 The exceptional sliding and thermal Ampco 673* Ampco 45 Ampco M4 Offers excellent corrosion-resistance Used for heavier loads under abrasive transfer characteristics of Ampco 25 Widely specified for applications such A high strength alloy with mechanical A truly exceptional alloy that has been and outstanding friction tolerance. conditions where no impact forces are have been proven to eliminate such as bushings, cams, nuts and bolts, properties beyond the range of com- heat-treated utilising the marannealing Used in applications such as fittings, present, for example, tube bending problems and enable greater defor- connector rods, shafts, worm gears mercial nickel-aluminium bronzes process to produce a material with fasteners, ball socket seats, bearings tools and mandrels, forming rolls, pilot mation levels - such that the number and lead screw nuts in corrosive resulting from a special manufacturing mechanical properties and a strength- and tie rods in brine slurry equipment. bushings, dies and drill jig bushings. of production stages may be reduced, environments, the higher lead content process employed by Ampco Metal. weight ratio far exceeding the range of Ampco 15* Ampco 21 also offers proven perfor- productivity increased, rejections of Ampco 673 results in an increase Applications that involve abrasive commercial aluminium bronzes. Suitable for moderate-wear service mance in plastic moulding applications eliminated and profits enhanced. of machinability over its sister alloy, wear, friction, mechanical deformation The high hardness of Ampco M4 bushings, sleeve bearings and bearing such as ejector sleeves and bushings, Readily polished to a high “mirror” Ampco 863, but with a small reduction or chemical erosion such as aircraft coupled with superb resistance to races, gears, valve stems, valve guides guide pins and wear plates. finish by conventional methods, in mechanical properties. bearings/bushings, pump and marine deformation and abrasion, makes this and seats. Ampco 22 Ampco 25 is chosen by the domestic Ampco 863* shafts, wear rings, valve spindles and material ideal for applications involving Ampco 18 Used principally for forming and appliance sector for the pressing of The higher strength and corrosion seats or machine tool parts, will heavy dynamic loads, abrasive wear The primary Ampco alloy for heavy duty drawing dies or wear parts under scratch-free stainless steel cooker resistance of this alloy make it an benefit from using Ampco 45. and frictional forces. In particular, applications involving wear, abrasion heavy compressive loads together with and refrigerator fronts, extractor ideal material for use in the heavy-duty The spark-resistance properties of Ampco M4 is used extensively in and fatigue, where the absence of cam rollers and followers. Ampco 22 is hoods, cooking utensils and a host construction and agricultural this alloy make it suitable for the commercial and military aircraft nickel in its composition significantly also recommended for plastic mould of other items that find a place in our equipment sectors. By outperforming production of safety tools and landing gear assemblies, for tube reduces the risk of mechanical applications requiring maximum metal day-to-day lives. The prominence of conventional bronzes, Ampco 863 has machine tool components used in manipulation tools and for parts abrasion with mating steel surfaces. to metal wear resistance. stainless steel in beer barrel produc- found considerable success in explosive environments. operating under load in adverse This is the material of choice for wear Ampco 25 tion and a subsequent need for higher applications such as bearings, worm Ampco 483* environments, such as the conditions plates, bearings, tie bar nuts, gears, A superb high hardness alloy for the deformation levels of the thicker gears, cams and in particular, segmen- Offers exceptional corrosion and experienced in off-shore drilling worm- wheels, tube bending tools, efficient production of quality steels needed to withstand the rough ted bushings and sleeve bearings. cavitation resistance with high situations. wiper dies and similar applications. pressings, principally in stainless steel handling such barrels receive in their strength, excellent ductility and good Ampco 18 is readily machined and but equally proficient for titanium, low use, has resulted in Ampco 25 draw weldability. Typical applications are should be used in critical situations carbon steels and other deep-drawn or rings becoming the essential choice found in marine service, fittings, *Please ask your local Ampco Metal where it is essential to avoid unneces- formed metals. of manufacturers in this industry. couplings, fasteners, etc. and for representative for availability. sary down-time or damage to moving With the move towards using thinner, Ampco 26 components operating within other steel parts. The mechanical properties harder steels in many sectors, A harder derivative of Ampco 25 for corrosive environments. of Ampco 18 can be enhanced by including automotive production, use in exceptional circumstances special heat-treatments devised by conventional press tools are prone to where severe service conditions are Ampco Metal to meet specific rapid heating, leading to mechanical encountered. customer demands for higher impact bonding with the moulded component Ampco 642* resistance or resistance to distortion,
Load more

Recommended publications
  • Corrosion Behaviour of Alpha Phase Aluminium Bronze Alloy in Selected Environments
    Leonardo Electronic Journal of Practices and Technologies Issue 24, January-June 2014 ISSN 1583-1078 p. 113-125 Corrosion Behaviour of Alpha Phase Aluminium Bronze Alloy in Selected Environments Oluwayomi BALOGUN1, 2*, Joseph BORODE2, Kenneth ALANEME2, and Michael BODUNRIN2 1Prototype Engineering Development Institute, (PEDI) Ilesa, Osun State. Nigeria. 2Metallurgical and Materials Engineering Department, Federal University of Technology Akure. Nigeria. Emails: [email protected]; [email protected]; [email protected] ; [email protected]. * Corresponding author: Phone: +234-8036362432 Abstract This research investigated the corrosion behaviour of aluminium (8 wt %) bronze alloys produced via sand casting in acidic, alkaline, and marine environments. The aluminium bronze was produced from aluminium (6063) alloy and copper scraps by sand casting according to European standard specification (UNS. C61400- CuAl8), after which they were cut into smaller sizes and immersed in the selected corrosive media for corrosion test investigation. H2SO4, NaCl, NaOH, and HCl of 0.1 M, 0.2 M, 0.3 M, 0.4 M, and 0.5 M were setup for 45 days for the corrosion study. Selective phase attack was observed in the alloy, although it was much more pronounced in HCl, to the point where entire grains fell out while it exhibit minimal corrosion resistance in marine and alkaline media respectively. Intense chloride attack on the protective film formed on the surface of the aluminium bronze was observed to be responsible for the greater corrosion susceptibility of the alloy in HCl environments. Comparative studies of aluminium bronze in selected environments indicated that no corrosion was observed and the alloys have a greater tendency to be applicable in marine, alkaline and sulphuric acid environments.
    [Show full text]
  • Aluminium Bronze Alloys Corrosion Resistance Guide
    Copper Development Association Archive for Research Purposes Aluminium Bronze Alloys Corrosion Resistance Guide Publication No 80, 1981 Aluminium Bronze Alloys Corrosion Resistance Guide Publication No 80 July 1981 Acknowledgements CDA gratefully acknowledges the assistance of the British Non-Ferrous Metals Technology Centre, Wantage, and in particular, Mr H S Campbell, in the preparation of this Guide on behalf of the CDA Aluminium Bronze Committee. Copper Development Association Copper Development Association is a non-trading organisation sponsored by the copper producers and fabricators to encourage the use of copper and copper alloys and to promote their correct and efficient application. Its services, which include the provision of technical advice and information, are available to those interested in the utilisation of copper in all its aspects. The Association also provides a link between research and user industries and maintains close contact with other copper development associations throughout the world. Website: www.cda.org.uk Email: [email protected] Copyright: All information in this document is the copyright of Copper Development Association Disclaimer: Whilst this document has been prepared with care, Copper Development Association can give no warranty regarding the contents and shall not be liable for any direct, indirect or consequential loss arising out of its use Contents Introduction.............................................................................................................................................
    [Show full text]
  • Aalco-Copper-Brass-Bronze.Pdf
    ® Company Profile Stainless Steel Aluminium Copper, Brass & Bronze General Data To receive a copy of any of the following literature or to download a pdf version please visit www.aalco.co.uk or contact your local Service Centre. Details on back cover. The information contained herein is based on our present knowledge and experience Weights and is given in good faith. However, no liability will be accepted by the Company in respect of any action taken by any third party in reliance thereon. All weights shown in this publication are for guidance only. They are calculated using nominal dimensions and scientifically recognised densities. Please note that in practice, As the products detailed herein may be used for a wide variety of purposes and as the the actual weight can vary significantly from the theoretical weight due to variations in Company has no control over their use, the Company specifically excludes all manufacturing tolerances and compositions. conditions or warranties expressed or implied by statute or otherwise as to dimensions, properties and/or their fitness for any particular purpose. Any advice given Copyright 2007: All Rights reserved: Aalco Metals Limited. No part of this publication by the Company to any third party is given for that party’s assistance only and without may be reproduced, sorted in a retrieval system or transmitted in any form or by any any liability on the part of the Company. means, electronic, mechanical, recording or otherwise without the prior written consent of the proprietor. Any contract between the Company and a customer will be subject to the Company’s Conditions of Sale.
    [Show full text]
  • RCI Industries & Technologies Limited
    RCI Industries & Technologies Limited Investor Presentation December 2018 Executive Summary Overview • RCI Industries & Technologies Ltd. (RCI) was incorporated in 1992 by Mr. Rajeev Gupta and is one of the leading manufacturers of diversified flat and round products in copper, brass and also in stainless steel and special alloys. • The company is headquartered out of New Delhi with manufacturing plants located in Himachal Pradesh with 24,000 MTPA capacity for Round products in Nalagarh and 6,000 MTPA for Flat Products in Baddi as on March 2018 which will go to 24,000 MTPA by September 2019. • The Company is listed on BSE and has a market capitalization of INR 914 Mn as of 30th September 2018. Business Mix • Flat Products – Copper, Brass, Aluminum, stainless steel-sheets, strips, foils and coils, Tin alloy solder – bars/sheets/strips etc. • Round Products – Annealed/un-annealed copper wires, bunched copper wires, also launching cables in the brand name of RIKAYAA • Other Businesses – Trading of Ferrous & non-ferrous metals such as Copper rods, Ingots, scrap, Zinc and other related items as the same is raw material for the manufacturing divisions. Some Marquee Clients FY18 Consolidated Financial Highlights • Havells • Total Income - INR 20,440 Mn • Technocraft Industries • EBITDA - INR 645 Mn; EBITDA Margins - 3.1% • Finolex • PAT - INR 328 Mn; PAT Margins - 1.6% • KDDL Ltd. • ROCE – 16.9% • Quality Industries • ROE – 14.3% 2 COMPANY OVERVIEW 3 Company Overview • RCI Industries & Technologies Ltd. (RCI) is the only company to manufacture both round and flat products in India and having the Revenue (INR Mn) & EBITDA Margins (%) most diversified customer portfolio both in domestic and overseas 5% 4.0% with 200+ customer base.
    [Show full text]
  • Modern Coinage Systems
    MODERN COINAGE SYSTEMS By MAJOR D. V. DEANE, C.I.E., C.B.E. {Formerly Senior Master of the Indian Government Mints) Preface. The subject of this paper covers a wide range of factors which influence the final decisions which must be made before a country can introduce a new series of coins, or even add a single new coin to the existing series. These new coinages have been necessitated for various reasons, such as the introduction of the Decimal System; the grant of Independence to a former colonial territory; the replacement of low valued currency notes by coins; and the steep increase in the price of silver during recent years, which has resulted in this metal now being almost completely abandoned for use in coinage. Each country which is considering changes in its currency or coinage presents its own particular problems. One of the most important of these is the face value of the major coinage unit of the country concerned, and of the sub-divisions thereof. In countries where the value of the major unit is high—such as the U.S. Dollar or the S. African Rand, there is a wide choice of metals and alloys for the subsidiary units, as even the lowest coin will have some intrinsic value, but in other countries—notably in Latin America—the problem is complicated by the much lower value of the major unit, and, with the steep inflationary trend which persists in many of these countries, by the risk of the metal value of the subsidiary coins eventually exceeding their face value to an extent where they disappear from circulation to be melted for use in the local non-ferrous industry.
    [Show full text]
  • Aluminium Bronze
    Aluminium Bronze CA104 / DTD197A DEF STAN 02-833 www.columbiametals.com C63000 / AMS4640 DEF STAN 02-834 [email protected] Aluminium bronzes are the most widely used of all the high performance copper alloys mainly due to their superb blend of strength and corrosion resistance. These properties ensure the alloys are widely utilised in marine and offshore applications in seawater and under adverse atmospheric conditions. This essential group of engineering alloys also services the aerospace, automotive and petrochemical Aluminium Bronze industries together with general engineering requirements. Aluminium bronzes are primarily copper-based alloys with an aluminium content of between 6 and 14%. Other alloying additions such as nickel, iron, manganese and silicon can be made to enhance the properties of individual grades. There are three main types of aluminium bronze: the single-phase alpha alloys containing less than 8% aluminium; the two-phase or duplex grades containing between 8 and 11% aluminium (these are usually alloyed with iron and nickel); and the copper aluminium and silicon alloys known as aluminium silicon bronzes. The most popular engineering alloys fall into the duplex category and are usually alloyed with iron and nickel to achieve higher strength and corrosion resistance, whilst the higher aluminium content creates a hard beta phase in the microstructure that improves overall strength and hardness. Aluminium silicon bronzes are mainly utilised in marine applications. The most popular grades of aluminium bronze, all stocked by Columbia Metals in a wide range of sizes in round bar, hexagon and sheet, are described below. CA104 / CW307G / BS2 B23 / DTD197A These alloys are classed as 10/5/5 nickel aluminium bronzes as the nominal composition is 10% aluminium, 5% nickel and 5% iron, with the remainder made up of copper.
    [Show full text]
  • Brass Versus Bronze in Material Selection You Also Might Be Interested in One of Our Products Made from Brass
    www.herz.eu Brass versus Bronze in material selection You also might be interested in one of our products made from brass: www.herz.eu www.herz.eu www.herz.eu Automatic Balancing Valves Ball Valves DE LUXE for hydraulic balancing for gas, water, heating, air-conditioning, Radiator valves - perfect aesthetics ventilation and sanitation systems 1 Automatic Balancing Valves HERZ Ball valves HERZ DE LUXE www.herz.eu www.herz.eu www.HERZ.eu Gas Installations Drinking Water Systems Commissioning Centre engineering services Gas Installations Drinking Water Systems HERZ Commissioning Centre engineering services Table of contents Copper .......................................................................................................................................... 1 Bronzes ......................................................................................................................................... 2 Manganese bronzes ................................................................................................................ 2 White manganese bronzes ...................................................................................................... 2 Aluminum bronzes ................................................................................................................... 2 Nickel bronzes ......................................................................................................................... 2 Silicon bronzes .....................................................................................................................
    [Show full text]
  • Comparison of Cast Bronze with Cast Duplex Stainless Steel
    Comparison of Cast Bronze with Cast Duplex Stainless Steel All metals deteriorate over time and will ultimately return to their mineral state, the speed of which is dependant on the environment they are placed in and how well they are maintained . Before any comparison is made it is important to explain that not all Bronze is of Naval Engineering Standard (NES 747). This standard refers to heat treated, cast nickel aluminium bronze, which is the preferred bronze for sea water conditions. Many bronze marine products on the market today are either aluminium bronze or silicone bronze, these do not perform at the same level as the above. Cast bronze can have many impurities which affect the ability to resist corrosion in a sea water environment. Manufacturers of bronze marine fittings often neglect to clarify the type of bronze used. This should always be checked as performance does vary. Similarly, there are various stainless steels. The 300 series stainless steels are generally considered to resist rust, however 304 is inadequate for marine applications, where 316 is the accepted marine grade stainless steel. 316 shows good general resistance to corrosion and is widely used, however in certain applications (specifically where there is no oxygen present) 316 will be susceptible to corrosion. To increase resistance to corrosion a surface treatment such as electro polishing will provide extra protection. Alternatively there are superior grades of stainless steel which offer almost twice the resistance to corrosion that ordinary 316 or 316L offers. These include duplex stainless steel (2205), super duplex SS (2507). Research conducted in the UK comparing nickel aluminium bronze (NES 747) with various stainless steels in an offshore sea water environment, revealed some interesting findings.
    [Show full text]
  • The Manufacture of Aluminium-Bronze Castings
    The manufacture of aluminium-bronze castings L. R. VAIDYANATH T HE development of aluminium-bronze alloys has SYNOPSIS basically been due to a combination of useful pro- perties particuarly appealing to the designers in Employing practices and equipment generally, available various engineering fields, the most important applica- for copper allv.r castings like gun metals and phosphor- tion being in the marine and hydraulic field. Important bronze, attempts have been made by Indian foundries to properties of aluminium-bronzes include the follo%%ing manufacture aluminium-bronze castings trithout under- standing its basic principles. The paper has tried to deal (1) Useful combination of mechanical properties with frith factors that should be considered for economic pro- ability to retain these properties at moderately duction of aluminium-bronze castings. elevated temperature Briefly explaining the metallurgy of the alloy, the (2) Excellent resistance to corrosion and cavitation parameters governing foundry practice of aluminium- erosion bronze have been discussed. Factors like the effect of (3) High impact value, and short freezing range, structure, effect of casting and (4) High wear resistance. mould variables on mechanical properties, control of composition and gas absorption, etc. are explained. In the design of castings. weight plays an important Concluding, suggestions have been made to adopt such part both from the economical and functional points techniques that would give a sound casting. of view and castings of aluminium-bronzes have ful- filled these requirements admirably. Perhaps this is the only alloy in the copper alloy series where almost 80% tic knowledge of the alloy through experience is of the test bar strength can he achieved in castings.
    [Show full text]
  • Effect of Heat Treatment Parameters on the Mechanical Properties and Microstructure of Aluminium Bronze
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper ID: TG-20170827194345 EFFECT OF HEAT TREATMENT PARAMETERS ON THE MECHANICAL PROPERTIES AND MICROSTRUCTURE OF ALUMINIUM BRONZE Božidar MATIJEVIĆ, Thota Surya Krishna SUSHMA, B. K. PRATHVI Abstract: Aluminium bronzes are used for their combination of high strength, excellent corrosion and wear resistance. This paper presents the research of heat treatment parameters of two different chemical compositions of aluminium bronze (Cu-Al-Fe- Ni alloy) on microstructure and mechanical properties. The heat treatment employed in this research were solutionizing and tempering. The solution treatment was carried out at a temperature of 950 °C and the duration in the range of two hours. Similarly, tempering was carried out at 300 °C and 400 °C, wherein the duration was maintained at two hours. The heat treated samples were subjected to the cold water quenching in order to bring them to an ambient temperature. Metallographic studies were performed on samples in order to determine the changes in the microstructure of the hardened bronze, on the metallographic microscope OLYMPUS GX51 with a digital image analysis and the scanning electron microscope TESCAN VEGA 5136MM with EDX along with the digital recording on the computer. Moreover, the Glow Discharge Spectroscopy-GDS was done to determine the chemical composition of the samples. The results of the chemical composition for the aluminium bronze AK2 were: Cu- 78,37%; Al- 10,52%; Fe- 4,44%; Ni- 5,16% and for AK3 alloy: Cu- 78,95%, Al- 10,97%; Fe- 4,16%; Ni- 4,8%.
    [Show full text]
  • Aluminium Bronze: an Alternative to Duplex Steels in Pump Design
    TECHNICAL ARTICLE TECHNICAL ARTICLE Aluminium Bronze: An Alternative to Duplex Steels in Pump Design Bronze alloys are very well known for friction related applications whereas Aluminium Bronze or Nickel Aluminium Bronze alloys are much less known; yet, they offer unique corrosion characteristics as required by pumps, especially in sea water applications, along with interesting biofouling properties. Those two properties make them a preferred solution for all marine related applications (pumps, valves, heat exchangers and propulsion systems). By Olivier Gouriou, Sales Manager, Inoxyda; Laurent Robin, Sales Manager, Saint Remy Industrie; and Jean Wintzer, Sales Manager, Les Bronzes d’Industrie Interesting properties of Aluminium With a main property being the protective oxide surface Bronze for pumps flm, which has the ability to self-repair, it outlasts steel coated applications in the long run. Aluminium Bronze is a family of alloys including The family of Nickel Aluminium Bronze (NAB) is copper, aluminium, nickel, iron and manganese. Each available according to various international standards individual component can be easily adjusted to improve (EN 1982, ASTM B148, BS…); each having specifc strength, corrosion resistance and/or machinability. properties, some examples are listed in Table 1 below. Those combinations allow a unique set of properties, (see Optimum corrosion protection is reached when: Table 1) which are useful in many pump applications: • An additional heat treatment at 675°C for six hours is • High strength applied •
    [Show full text]
  • Guide to Nickel Aluminium Bronze for Engineers
    6.0 Corrosion Resistance The corrosion mechanisms described are mainly based on data and experience in seawater but nickel aluminium bronze also has good corrosion resistance in many chemical environments. 6.1 Protective Surface Film Nickel aluminium bronze relies on the formation of a thin adherent copper/aluminium-rich oxide film of Cu2O and Al2O3, which is self-repairing - even in media containing low oxygen levels. The oxide layer also contains iron and nickel oxides which tend to form under longer exposure and, the greater the concentration of oxygen, the more protective is the film(5) . It is vitally important in the commissioning of equipment, particularly in seawater applications, that the system is flushed through with clean aerated seawater for several hours to assist in building up the protective layer and this is important for long-term corrosion resistance. On occasion, new marine vessels in dock are flushed through with contaminated water and this has proved to be problematic if the water contains high sulphide levels. The protection against corrosion given by the oxide film can be summarised by the following properties: • It adheres firmly to the surface of the substrate • It has an initial thickness of ~0.001 mm and has resistance to liquid penetration • It has the ability to self-repair in non-deaerated conditions • It has good resistance to liquid flow velocity below the recommended value of 4.3 m/sec. At lower velocities the film thickness will tend to increase with time, reaching a steady corrosion rate of ~0.05 mm per year • The hardness of the alumina content of the film (Al2O3) creates higher resistance to erosion and abrasion.
    [Show full text]