COPPER CASTING ALLOYS - Copper Development Association

114 Pages·2007·27.95 MB·English

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