Copper Development Association Publication 117 The Brasses properties & applications CDA Publication No. 117, 1996 by Vin Callcut Revised 2005 by Peter Webster COPPER DEVELOPMENT ASSOCIATION (Limited by guarantee) MEMBERS, as at April 2005 BrazeTec Codelco Services Ltd Ecosea Ltd IBP Conex Mueller Europe Copper Tube & Fittings Noranda Islandi ehf Outokumpu Copper Metal Supplies Ltd Rio Tinto London Ltd SANHA UK Ltd Southern Peru Copper Corporation The British Non-Ferrous Metals Federation Wieland–Werke (UK) Ltd WMC Resources Ltd Yorkshire Copper Tube Ltd Yorkshire Fittings Ltd 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 the user industries and maintains close contact with other copper development organisations throughout the world. ACKNOWLEDGEMENTS This revision was financed by International Copper Association, European Copper Institute and Rio Tinto London Ltd. In the preparation of the 1996 text CDA is pleased to acknowledge with thanks significant help given by Hector Campbell, John Nicholson and John Westlake. For the 2005 revision thanks are due to: Vin Callcut Sean Hammond (Tungum Ltd) Keith Ingram (Consultant) Ken Kempson Roger Thompson (Armack Chemicals Ltd) Mark Thomson-Tur (Cole & Swallow Materials Ltd) Mike Treadwell (Outokumpu Copper MKM Ltd) Copper Development Association 5 Grovelands Business Centre PHOTOGRAPHY Boundary Way All photography by Vin Callcut unless otherwise credited. Hemel Hempstead Hertfordshire HP2 7TE Disclaimer Tel: +44 (0)1442 275700 Whilst this document has been prepared with care, we can give no warranty regarding Fax: +44 (0)1442 275716 the contents and shall not be liable for any direct, incidental or consequential damage arising out of its use. For complete information on any material the appropriate Email: [email protected] standard should be consulted. Websites: www.cda.org.uk www.brass.org The Brasses properties & applications Section 1 INTRODUCTION page 5 An introduction to the topics and examples of typical applications. Section 2 WHY MAKE IT IN BRASS? page 6 Explains the very wide variety of combinations of properties unique to brasses that make them the most cost-effective materials to select for the manufacture of a vast range of products. Section 3 CHOOSING THE RIGHT BRASS page 15 Gives details of the many types of brass available to meet end-user requirements and basic materials selection guidance. Section 4 WHICH FORMS OF BRASS? page 19 Describes the extensive range of shapes and sizes available and the way in which they can be made. There is also coverage of the old British Standards and material designations and the EN standards and designations which have replaced them. Section 5 HOW TO MAKE IT IN BRASS page 29 Gives details of common forming, fabrication, machining and finishing techniques that can be used in the production of brass components. Section 6 TYPES OF BRASS page 35 Details the basic metallurgy of brasses and the useful effects of alloying additions. Section 7 BRASSES FOR CORROSION RESISTANCE page 45 Provides information to help select materials for use in particularly aggressive environments. Section 8 BRIEF HISTORY OF BRASS page 61 Shows the early development of the production and usage of brasses from Egyptian, Grecian and Roman times onwards. Section 9 INDEX page 62 1 CONTENTS Section 1 – INTRODUCTION 5 Section 2 – WHY MAKE IT IN BRASS? 6 COST-EFFECTIVENESS 6 LOW COST MANUFACTURING 9 CORROSION RESISTANCE 10 MACHINABILITY 11 Section 3 – CHOOSING THE RIGHT BRASS 15 BRASSES FOR SPECIFIC MANUFACTURING PROCESSES 15 BRASSES FOR SPECIAL APPLICATIONS 16 Section 4 – WHICH FORMS OF BRASS? 19 EXTRUSIONS 19 HOT STAMPINGS 19 FORGINGS 19 WIRE 20 SHEET AND STRIP 20 TUBE 21 PLATE 21 CASTINGS 21 ORDERING INFORMATION 22 CASE HISTORIES 27 2 CONTENTS - continued Section 5 – HOW TO MAKE IT IN BRASS 29 FABRICATION AND JOINING 29 FORMING BRASS 29 HEAT TREATMENT 29 JOINING BRASSES 30 MACHINING 31 EXTRA SURFACE PROTECTION 31 Section 6 – TYPES OF BRASS 35 EFFECT OF ALLOYING ADDITIONS 37 FREE MACHINING BRASSES 37 HIGH TENSILE BRASSES 38 EFFECT OF PROCESSING ON PROPERTIES 38 EFFECT OF ZINC CONTENT ON PROPERTIES 40 CASTABILITY 41 AVAILABLE FORMS AND PROPERTIES 41 Section 7 – BRASSES FOR CORROSION RESISTANCE 45 CORROSION RESISTANT APPLICATIONS OF BRASSES 45 CORROSION RESISTANCE DATA 48 TYPES OF CORROSION 48 Section 8 – A BRIEF HISTORY OF BRASS 61 Section 9 – INDEX 62 3 TABLES AND FIGURES Tables Table 22 Common size ranges of wrought and cast brasses (UK) 42 Table 1 Brasses – Typical engineering applications 5 Table 23 Tolerance classifications in EN specifications 42 Table 2 Comparison of first costs for heavy duty valve chests 7 Table 24 Applications of brasses in aggressive environments 49 Table 3 Relative machinability ratings of various metals 11 Table 25 Resistance of copper alloy heat exchanger tubes Table 4 to erosion corrosion in seawater 54 Practical metal removal rates 11 Table 26 Table 5 Physical properties of brasses 58 Comparison of typical mechanical properties of brasses, free-cutting mild steels and stainless steels 12 Figures Table 6 Figure 1 Free-machining brasses 15 Effect of temperature on properties of free-machining brass CW614N (CZ121) 7 Table 7 Figure 2 The most popular brasses for hot stamping 15 Tool geometry for the machining of brasses in Table 8 machinability groups 1 & 2 10 Brasses for cold working 16 Figure 3 Table 9 Comparison of costs of low alloy steel and brass studding 11 Brasses for casting 16 Figure 4 Copper-zinc partial phase diagram Table 10 (after Struers Scientific Instruments) 36 High tensile brasses included in EN Standards 17 Figure 5 Table 11 Effect of copper and lead content on Electrical conductivity and elastic modulus free-machining brass 37 of some brasses 17 Figure 6 Range of copper and lead contents available in Table 12 EN standards 38 Brasses available as extruded rod and section 19 Figure 7 Table 13 Simplified flowchart for brass component production 39 Brasses for hot stamping 19 Figure 8 Table 14 Effect of composition on mechanical properties Brass wire (EN 12166) 20 of brasses 40 Figure 9 Table 15 Effect of composition on moduli of brasses 40 Standard tolerances on diameter of round wire 20 Figure 10 Table 16 Effect of composition on thermal conductivity and electrical Brasses in sheet and strip form (EN 1652) 20 resistivity of brasses 41 Table 17 Figure 11 Brass tubes – General Purpose (EN 12449) 21 Effect of composition on heading limit 41 Figure 12 Table 18 Hardness v grain size for annealed European Standards for copper and copper alloys CuZn30 brass sheet and strip 42 covering brasses 23 Figure 13 Table 19 Relationship between chloride to carbonate hardness BS and European designations - summary of ratio and dezincification aggressiveness of waters 51 compositions for wrought products 24, 25 Figure 14 Table 20 Effect of zinc content on stress corrosion EN and old BS designations for cast products 26 susceptibility of brass 55 Figure 15 Table 21 Galvanic series for common metals and alloys Polymers used for clear coatings 33 in seawater 57 4 Section 1 – INTRODUCTION Brass is usually the first-choice material for many of the To suit every need, there are over sixty Standard compositions for components for equipment made in the general, electrical brass with copper contents ranging from 58% to 95%. and precision engineering industries. Brass is specified Apart from the major alloying element, zinc, small additions because of the unique combination of properties, matched (less than 5%) of other alloying elements are made to modify the by no other material, that make it indispensable where a properties so that the resulting material is fit for a given purpose. long, cost-effective service life is required. Brass Designations The generic term ‘brass’ covers a wide range of copper-zinc Brasses are described by a number of systems of common alloys with differing combinations of properties, including: terminology. As an example, in the old British Standards BS 2870 • Strength • Machinability to 2875, the designation CZ106 is referred to as ‘70/30 Brass’ or • Ductility • Wear resistance ‘Cartridge Brass’ or sometimes ‘Deep Drawing Brass’. • Hardness • Colour • Conductivity • Corrosion resistance In EN Standards the composition symbol for 70/30 Brass is CuZn30 and the material designation number is CW505L. In this Brasses can easily be cast to shape or fabricated by extrusion, publication the notation used in the text gives the EN number rolling, drawing, hot stamping and cold forming. first, followed by the old BS number in brackets. Hence, for the • The machinability of brass sets the standard by which above brass the designation is CW505L (CZ106). other materials are judged. • Brasses are ideal for a very wide range of applications. • Brass is frequently the cheapest material to select. • The correct choice of brass is important if manufacturing and operating requirements are to be met in the most cost-effective way. TABLE 1 – Brasses - typical engineering applications Form Cold Working Free-Machining High Tensile High Corrosion Resistance Unions Terminals Marine fittings Rivets Spindles Valve spindles Plumbing fittings Rods Pinions