COPPER CASTING ALLOYS ~CDA (hiTl) Non-Ferrous Founders' Society Copper Development Association COPPER CASTING ALLOYS PREFACE ................................................................ . .. ......................... ..4 FIGURES: FIGURES P-l to P-4. Typical Copper Casting Applications ................................................................. 5 UNDERSTANDING COPPER CASTING ALLOYS I. CLASSIFYING THE COPPER ALLOYS. .............. 7 Common Classification Systems .......................... . The UNS Numbering System ...................................................... . . ......................................... 7 The Copper Metal Families: Classification and Major Uses ..................... .. .. ..........................7 Metallurgy and Foundry Charactel;stics ............................... 10 Effects of Lead .... .. ............................................................................................. ............................. 11 TABLES: Alloy Characteristics TABLE I. Standard Temper Designations for Copper Casting Alloys ....................... . . ............................. 8 TABLE 2. Overview of Copper Casting Alloys ........................ . .. ........................ 12 TABLE 3. Typical Mechanical Properties of Copper Casting Alloys .................... .. .......................... 26 TABLE 4. Physical Properties of Copper Casting Alloys. .. ..... ..42 TABLE 5. Conforming Specifications for Copper Casting Alloys ..... .. .... ..47 FIGURES: FlGURES I-I to 1-3. Representative Copper Alloy Castings .. . . ....................................... 25 FIGURES 1-4 to 1-10. Representative Copper Alloy Castings ................ . . ..................................... .52,53 SELECTING COPPER CASTING ALLOYS II. SELECTING COPPER ALLOYS FOR CORROSION RESISTANCE .............................................................. .55 Fonns of Corrosion in Copper Alloys ...................................................................................... . .. .. 55 Selecting Alloys for Corrosive Environments ............................................................................................... 57 TABLE: TABLE 6. Velocity Guidelines for Copper Alloys in Pumps and Propellers in Seawater. .. ...... 61 FIGURES: FlGURES 11-1,11-2. Decreasing corrosion rate over time of Cu-Ni in Seawater. ............................. 61 FIGURE 11-3. Galvanic Series Chart ............................................................................................................. 62 III. SELECTING COPPER ALLOYS FOR MECHANICAL PROPERTIES ................. . ....6 3 Strength ............................................ . ...6 3 Strength and Temperature .................. . ..63 Friction and Wear .................................... ................................................ . ................................... . ... 64 Fatigue Strength ...................................................................................................... .. .. ............................. 64 FIGURES: FIGURES III-I to III-7. Effect of Temperature on Various Mechanical Properties for Selected Alloys................... .................................... ............. ........... .. .................................... 65-68 ~ CDA Non-Ferrous Founders' Society Copper Development Association 455 State Street· Des Plaines, IL 60016 260 Madison Avenue· New York, NY 10016 TABLE OF CONTENTS\continued IV. SELECTING COPPER ALLOYS FOR PHYSICAL PROPERTIES .. ...........................................6 9 Electrical Conductivity ................. . .................. 69 Thermal Conductivity ............................................................ . ................................. 69 FIGURES: FIGURES IV-I, JV-2. Temperature dependence of electrical and thermal conductivity for selected copper casting alloys ... .. .......................................................................................................W V. SELECTING COPPER ALLOYS FOR FABRICABILITY .................. . . .................. 71 Machinability .. . ................. 71 Weldability .... .. ..... 71 Brazing, Soldering ......... . .. ........................................................................................T I TABLES: Alloy Selection Criteria TABLE 7. Corrosion Ratings of Copper Casting Alloys in Various Media ......... . ...... 73 TABLE 8. Copper Casting Alloys Ranked by Typical Tensile Strength ........ . .. .... 76 TABLE 9. Copper Casting Alloys Ranked by Typical Yield Strength ... . ....... 78 TABLE 10. Copper Casting Alloys Ranked by Compressive Strength ......................................................... 80 TABLE II. Impact Properties of Copper Casting Alloys at Various Temperatures. . ................................ 81 TABLE 12. Creep Strengths of Selected Sand-Cast Copper Alloys.......................... .. ........... 82 TABLE 13. Stress-Rupture Properties of Selected Copper Casting Alloys .... .. ..... 83 TABLE 14. Common Bronze Bearing Alloys ................ . . .............. 84 TABLE 15. Fatigue Properties of Selected Copper Casting Alloys ....... 85 TABLE 16. Copper Casting Alloys Ranked by Electrical Conductivity ...................................................8 6 TABLE 17. Copper Casting Alloys Ranked by Thermal Conductivity ..................8 7 TABLE 18. Copper Casting Alloys Ranked by Machinability Rating ........ 88 TABLE 19. Joining Characteristics of Selected Copper Casting Alloys ...................................... 89 TABLE 20. Technical Factors in the Choice of Casting Method for Copper Alloys ................................... 91 FIGURES: FIGURES V-I, V-2. Examples of Welded Cast Structures ............................................ . . .............. 70 WORKING WITH COPPER CASTING ALLOYS VI. CASTING PROCESSES. ...................... 93 Processes for General Shapes ... . ........................................................................................... 93 Processes for Specific Shapes ................ . . ... 96 Special Casting Processes ....... . .......... 96 Selecting a Casting Process ..................................................... ...9 7 FIGURES: FIGURES VI-Ia,b. Sand Casting ................................ .................. .. .......................................................................... 98 FIGURES VI-2a,b. Shell Molding .................................................................................................................... 99 FIGURES VI-3a,b. Investment Casting ................................................................................................... 100,101 FIGURES VI-4a,b,c. Pennanent Mold ........................................................................................................... 101 FIGURES VI-5a,b. Die Casting ...................................................................................................................... 102 FIGURES VI-6a,b. Continuous Casting ......................................................................................................... 10 3 FIGURES VI-7a,b,c. Centrifugal Casting ....................................................................................................... 10 3 VII. CASTING DESIGN PRINCiPLES ............................................................................................................ 104 Design Fundamentals ....................................................................................................................................... 10 4 FIGURES: FIGURES Vll-I to Vll4. Casting Design Considerations ..................................................................... 106,107 SPECIFYING AND BUYING COPPER CASTING AllOYS VIII. ORDERING A COPPER ALLOY CASTING ............................................................................................ 109 Sample Purchase Order for a Sand Casting .................................................................................................... 110 REFERENCES ................................................................................................................................................1 11 Published 1994 by Copper Development Association Inc., 260 Madison A venue, New York, NY 10016 PHOTOGRAPHY ACKNOWLEDGMENTS We wish to thank the following for providing photography or the items used for photography in this publication. Ampco Metal, Inc. Brush Wellman Birkett Canadian Copper & Brass Development Association Hayward Tyler Fluid Dynamics Ltd. J.W. Singer & Sons, Ltd. Southern Centrifugal Square D Company Stone Manganese Marine Westley Brothers Wisconsin Centrifugal This Handbook has been prepared for the use of engineers, designers and purchasing managers involved in the selection, design or machining of copper rod alloys. It has been compiled from infonnation supplied by testing, research, manufacturing, standards, and consulting organizations that Copper Development Association Inc. believes to be competent sources for such data. However, CDA assumes no responsibility or liability of any kind in connection with the Handbook or its use by any person or organization and makes no representations or warranties of any kind thereby_ 70t4-0009 PREFACE This guide was prepared for indi known characteristic. The alloys against steel. For worm gears, nickel viduals who select, specify and buy have a natural corrosion resistance, bronzes and tin bronzes are industry materials for cast copper alloy products. making durability without mainte standards. Its purpose is to help engineers, design nance an important element of their Equally important, the copper ers and purchasing agents understand long-term cost-effectiveness. alloys' broad range of mechanical copper alloys so they can choose the Not surprisingly, water han properties enables the designer to most suitable and most economical dling equipment of one form or match a specific alloy with a bear material to meet their product's require another constitutes the cast alloys' ing's precise operating requirements. ments. largest single market. Copper alloy Cast sleeve bearings are shown in There have been several excellent castings are also widely used to han Figure P-2. A comprehensive dis texts on copper casting alloys published dle corrosive industrial and process cussion of copper bearing alloys can in recent years,1.! but these were written chemicals, and they are well known be found in the CDA publication, more for the foundry operator than for in the food, beverage and dairy Cast Bronze Bearings - Alloy designers. engineers and purchasing industries. Figure P-l shows several Selection and Bearing Design agents. The collections of technical data aluminum bronze pickJing hooks on cast copper alloys that were pub used to immerse coils of steel wire Biofouling Resistance. Copper effec lished in the 1960s,' 19 70s' and as in hot, dilute sulfuric acid. tively inhibits algae, barnacles and other marine organisms from attaching recently as 1990' are either out of print or have not been widely distributed. As Favorable Mechanical Properties. themselves to submerged surfaces. Pure copper is soft and ductile, and it a result, few individuals are fully aware Nonfouling behavior is highest in pure is understandably used more often of all the technical, economic and prac copper and high copper alloys, but it is for its high conductivity than for its also strong in the alloys used in marine tical advantages that the large family of mechanical strength. Some cast cop copper alloys has to offer. The present service. Products such as seawater pip per alloys, on the other hand, have guide, written specifically for the design ing, pumps and valves made from cop strengths that rival quenched and community, was prepared to fill this per alloys therefore remain free from tempered steels. information gap. biomass buildup and are able to operate Almost all copper alloys retain continuously without the periodic Why Specify Cast Copper Alloys? their mechanical properties, includ cleanup needed with steel, rubber or ing impact toughness. at very low Cast copper alloys have an fiber-reinforced plastic products. temperatures. Other alloys are used extremely broad range of application. routinely at temperatures as high as High Electrical and Thermal They are used in virtually every industrial 800 F (425 C). No class of engineer Conductivity. Copper's electrical market category, from ordinary plumbing and thermal conductivities are higher ing materials can match the copper goods to precision electronic components alloys' combination of strength, than any other metal's except silver. and state-of-the-art marine and nuclear corrosion resistance and thermal Even copper alloys with relatively equipment. Their favorable properties are and electrical conductivities over low conductivities compared with often available in useful combinations. such a broad temperature range. pure copper conduct heat and elec This is particularly valuable when, as is tricity far better than other structural usually the case, a product must satisfY metals such as stainless steels and several requirements simultaneously. Friction and Wear Properties. titanium. The following properties are the Cast sleeve bearings are an impor Unlike most other metals, the reasons cast copper alloys are most often tant application for copper alloys, thermal conductivity of many copper selected: largely because of their excellent tri casting alloys increases with rising Excellent Corrosion Resistance. bological properties. For sleeve bear temperature. This can improve the The ability to withstand corrosive ings. no material of comparable efficiency of copper alloy heat environments is the cast copper strength can match high leaded exchangers. Electrical conductivity alloys' most important and best- bronzes in terms of low wear rates generally decreases with increasing 4 alloy content, but even relatively processes, castability rarely restricts Reasonable Cost. The copper alloys' highly alloyed brasses and bronzes product design. predictable castability raises foundry retain sufficient conductivity for use yields, keeping costs low. Copper alloy • Excellent Machinability and as electrical hardware. For example, castings easily compete with stainless Fabricability. Almost all castings the hot-line clamp shown in Figure steels and nickel-base alloys, which can require some machining; therefore, P-3 is made from Alloy C84400, a be difficult to cast and machine. the copper alloy's machinability leaded semi-red brass whose electri Copper's initial metal cost may should be an important design con cal conductivity is only 16% that of appear high compared with carbon sideration. High surface finishes and pure copper. Nevertheless, the alloy steel, but when the cost is offset by good tolerance control are the nOnTIS has the proper combination of copper's additional service life and the with these materials. The leaded cop strength and conductivity required high value of the fully recyclable cast per alloys are free-cutting and can be for this safety- related application. ing when it is no longer needed, cop machined at ultrahigh speeds. per's life cycle cost is very competitive. Other characteristics of the Many unleaded copper alloys copper casting alloys can make prod can also be machined easily. For The following chapters discuss ucts simpler and less costly to produce. example. nickle-aluminum bronze these important qualities of copper alloys For example: was selected for the motor segment in detail. Where appropriate, the metals are shown in Figure P-4 in part because ranked according to their mechanical and Good Castability. All copper alloys it enabled a 50% savings in machin physical properties. The intent is to allow can be sand cast. Many compositions ing costs compared with stainless the designer to compare alloys and casting can also be specified for permanent steel. Another factor to consider is processes with the intended product's mold, plaster, precision and die cast that many copper alloys are weldable requirements. By consulting the appropri ings, while continuous casting and using a variety of techniques. This ate tables, it should be possible to narrow centrifugal casting are applicable to opens the possibility of economical the choice to a small number of suitable virtually all of the copper alloys. cast-weld fabrication. Almost all cop candidate alloys. Final selection can then With such a wide choice of per alloys can be brazed and soldered. be made on the basis of detailed product requirements, availability and cost. FIGURE P-2 Cast sleeve bearings are available in a large variety of copper alloys. FIGURE P-1 Cast aluminum bronze pickling hooks resist corrosion by hot, dilute sulfuric acid. FIGURE P-3 A leaded semi-red brass was selected for this hot line clamp because it offers an economical combination FIGURE P-4 of strength and corrosion The aluminum bronze chosen for this complex motor resistance with adequate segment casting enabled a 50% savings electrical conductivity. in machining costs compared with stainless steel. 5 Understanding Copper Casting Alloys I. CLASSIFYING THE COPPER ALLOYS Over the years, copper alloys 5% lead and 5% zinc is simply called lion. heat treatment. and/or casting have been identified by individual "85-5-5-5." while a leaded tin bronze is method. The terminology associated names and by a variety of numbering somewhat awkwardly designated as 88- with tempers is spelled out in ASTM B systems. Many of these names and 6-llh-4Ih. The system is limited to cop 601.7 and temper designations applica numbers are still used. often inter per-tin-lead-zinc alloys (always given in ble to cast alloys are listed in Table 1, changeably, and because this can be that order). but there are some exceptions. page S. For convenience. Table 2, page confusing. we will briefly explain how Vatious other naming and/or num 12, lists the alloys by UNS number, the various identification systems relate bering systems are used by. for example. common name and conforming specifi to each other. With this as a foundation. ingot suppliers who fumish casting stock cations. we will next describe the families of to foundries. or designers who. when The UNS alloy list is updated copper alloys as they arc categorized in they specify alloys, commonly call out periodically. New alloys may be added lOday's nomenclature. In this chapter, ASTM or ASME standards or military on request to COA, subject to a few we will also briefly discusses the vari specifications. None of these systems is simple restrictions, while alloys that are ous metals' metallurgical structures and obsolete; they are just not in general use no longer produced are deleted. The foundry characteristics, since these are in all industries. alloys described in this handbook are important considerations when deciding listed in CDA's Standard Designations The UNS Numbering System how a casting should be produced. j(Jr Wrought alld Cast Copper al1d In North America. the accepted Copper Allol's, 1992 edition. Common Classification Systems designations for cast copper alloys are The Copper Alloy Families: A 1939 American Society for now part of the Unified Numbering Classification and Major Uses Testing and Materials (ASTM) stan System for Metals and Alloys (UNS), dard, Classification of Copper-Base which is managed jointly by the ASTM Cast copper alloys are assigned Alloys, codified 23 distinct alloy fami and the Society of AUlOmotive Engineers UNS numbers from C80000 to C99999. lies based on general compositional (SAE). Under the UNS system, the cop The metals are arranged in a series of limits. Already-familiar designations per alloys' identifiers take the form of eight families drawn from the 18 com such as "Leaded Brass," "Tin Bronze" five-digit ccx1es preceded by the letter "c." positionally related classifications pre and "Aluminum Bronze" were associat The five-digit codes are based on, viously identified by the ASTM. These ed for the first time with specific com and supersede, an older three-digit sys families. some of which include sub position ranges. tem developed by the U.s, copper and classifications. include: Soon, other ASTM standards brass industry. The older system was Coppers (C80100-C81200). added designations for individual alloys administered by the Copper Coppers are high-purity metals with a within the families. For example, Development Association (CDA), and minimum designated copper content of "Leaded Semi-Red Brass SA" was alloys are still sometimes identified by 99.3%. They are not intentionally defined as an alloy containing between their "CDA numbers." The UNS desig alloyed but may contain traces of silver 78% and 82% copper, 2.25% to 3.25% nations for copper alloys are simply two or deoxidizers. The phosphorus deoxi tin, 6% to 8% lead and 7% to 10% zinc, digit extensions of the CDA numbers. dizer in, for example, CSI200 renders with stated limits on impurities. For example, the leaded red brass (85-5- this copper somewhat easier to weld by Minimum mechanical propelties were 5-5), once known as CDA Copper Alloy oxyacetylene techniques. also fixed, permitting alloys to be No. 836, became UNS C83600. The coppers are soft and ductile called out in design specifications and This selection guide uses UNS and are used almost exclusively for construction codes. numbers for all alloys, but traditional their unsurpassed electrical and thermal Another classification system still names are included for clarity wherever conductivities in products such as termi in use identifies alloys in terms of their appropriate. In addition, alloys are nals, connectors and (water-cooled) hot nominal compositions. Thus, a leaded described by their tempers, which are metal handling equipment. Figure 1-1, red brass containing 85% copper, 5% tin, terms that define metallurgical condi- page 25, shows a blast fumace tuyere 7 more than 160 ksi (1,100 MPa), the Red and Semi-Red Brasses, TABLE 1. Standard Temper beryllium coppers have the highest ten· Unleaded and Leaded (C83300- Designations for sile strengths of all the copper alloys. C84800). The most important brasses in Copper Casting Alloys They are used in heavy duty mechanical tenns of tonnage poured are the leaded (Based on ASTM B 601) and electromechanical equipment requi red brass, C83600 (85-5-5-5), and the ring ultrahigh strength and good electri leaded semi-red brasses, C84400, Temper Designations Temper Names cal and/or thennal conductivity. The C84500 and C84800 (81-3-7-9, 78-3-7- Annealed-O resistance welding machine component 12 and 76-3-6-15, respectively). All of 010 Cast and Annealed (Homogenized) shown in Figure 1.2, page 25, was cast these alloys are widely used in water 011 As Cast and Precipitation in beryllium copper for precisely those valves, pumps, pipe fittings and plumb Heat Treated reasons. ing hardware. A typical downstream The high copper alloys' corrosion water meter is shown in Figure 1-3, As-Manufaclured- M resistance is as good as or better than page 25. MOl As Sand Cast M02 As Centrifugal Cast that of pure copper. It is adequate for Yellow Brasses (C85200- M03 As Plaster Cast electrical and electronic products used C85800). Leaded yellow brasses such MO' As Pressure Die Cast outdoors or in marine environments, as C85400 (67-1-3-29), C85700 MOS As Permanent Mold Cast M06 As Investment Cast which generally do not require extraor (63-1-1-35) and C85800 are relatively MOl As Continuous Cast dinary corrosion protection. low in cost and have excellent castabili Brasses (C83300-C87900). ty, high machinability and favorable Heat-Treated-TO Brasses are copper alloys in which zinc finishing characteristics. Their corrosion TOD~ Quench Hardened T030 Quench Hardened and is the principal alloying addition. resistance, while reasonably good, is Tempered Brasses may also contain specified lower than that of the red and semi-red TOSO Quench Hardened and quantities of lead, tin, manganese and brasses. Typical tensile strengths range Temper Annealed silicon. There are five subcategories of from 34 to 55 ksi (234 to 379 MPa). cast brasses, including two groups of Leaded yellow brasses are com Solution Heal Treated and Spinodal Heat copper·tin-(lead)-zinc alloys: monly used for mechanical products Treated-TX C833()()"c838I 0 and C842()()"c84800. such as gears and machine components, TXOO Spinodal Hardened (AT) the red and leaded red brasses and semi in which relatively high strength and red and leaded semi-red brasses, respec moderate con'osion resistance must be Solution Heal tively; combined with superior machinability, Treated-TB TBOO Solution Heat Treated (A) copper·zinc-(lead) alloys, C85200- The yellow brasses are often used for C85800, yellow brasses and leaded architectural trim and decorative hard Solution Heat Treated yellow brasses; ware, The relatively narrow solidifica and Precipitation Heal manganese bronzes and leaded man tion range and good high-temperature Treated-TF ganese bronzes, C861 QO-{:86800, ductility of the yellow brasses permit TfOO Precipitation Hardened (AT) also known as high strength and lead some of these alloys to be die cast. The ed high strength yellow brasses; and, yellow brass door bolt shown in Figure cast from high conductivity copper. The copper-silicon alloys, C87300- 1-4, page 52, was pressure die cast to coppers have very high corrosion resis C87900, which are called silicon near net shape, thereby avoiding the tance, but this is usually a secondary brasses or, if they contain more sili costly machining and fonning operations consideration. con than zinc, silicon bronzes. needed in an alternative manufacturing High Copper Alloys (C81400- method. Other die-castable alloys include The lower the zinc content in the C82800). Next in order of decreasing the structurally similar high strength copper-tin-(lead)-zinc alloys. the more copper content are alloys with a mini yellow brasses and the silicon brasses. copper-like, or "red" they appear. With mum designated purity of 94% Cu. The High Strength and Leaded High a few exceptions, red and leaded red high copper alloys are used primarily Strength Yellow Brasses (C86100- brasses contain less than about 8% zinc; for their unique combination of high C86800), or manganese bronzes, are the semi-red brasses, including the leaded strength and good conductivity. Their strongest, as cast, of all the copper versions, contain between 7% and 17% corrosion resistance can be better than alloys. The "all beta" alloys C86200 zinc, while yellow brasses and their that of copper itself. Chromium coppers and C86300 (the alloys' structure is leaded counterparts contain as much as (C81400 and C81500), with a tensile described below) develop typical tensile 41% zinc. Brasses containing up to strength of 45 ksi (310 MPa) and a con strengths of95 and 115 ksi (655 and 32.5% zinc are also sometimes called ductivity of 82% lACS (see page 86) 793 MPa), respectively, without heat "alpha" brasses after the common des (as heat treated), are used in electrical treatment. These alloys are weldable, ignation for their single-phase, face contacts, clamps, welding gear and sim but should be given a post-weld stress centered cubic crystal structure. ilar electromechanical hardware. At relief. The high strength brasses are 8