Copper alloys are metal alloys that have copper as their principal component. They have high resistance against corrosion. Of the large number of different types, the best known traditional types are bronze, where tin is a significant addition, and brass, using zinc instead. Both of these are imprecise terms. Latten is a further term, mostly used for coins with a very high copper content. Today the term copper alloy tends to be substituted for all of these, especially by museums. [1]
Copper deposits are abundant in most parts of the world (globally 70 parts per million), and it has therefore always been a relatively cheap metal. By contrast, tin is relatively rare (2 parts per million), and in Europe and the Mediterranean region, and even in prehistoric times had to be traded considerable distances, and was expensive, sometimes virtually unobtainable. Zinc was somewhere between these two in terms of rarity at 75 parts per million, but often harder to extract from its ores. Bronze with the ideal percentage of tin was therefore expensive and the proportion of tin often reduced to save cost. The discovery and exploitation of the Bolivian tin belt in the 19th century made tin far cheaper, although forecasts for future supplies are gloomy.
There are as many as 400 different copper and copper alloy compositions loosely grouped into the categories: copper, high copper alloy, brasses, bronzes, copper nickels, copper–nickel–zinc (nickel silver), leaded copper, and special alloys.
The similarity in external appearance of the various alloys, along with the different combinations of elements used when making each alloy, can lead to confusion when categorizing the different compositions. The following table lists the principal alloying element for four of the more common types used in modern industry, along with the name for each type. Historical types, such as those that characterize the Bronze Age, are vaguer as the mixtures were generally variable.
Family | Principal alloying element | UNS numbers |
---|---|---|
Copper alloys, brass | Zinc (Zn) | C1xxxx–C4xxxx,C66400–C69800 |
Phosphor bronze | Tin (Sn) | C5xxxx |
Aluminium bronzes | Aluminium (Al) | C60600–C64200 |
Silicon bronzes | Silicon (Si) | C64700–C66100 |
Cupronickel, nickel silvers | Nickel (Ni) | C7xxxx |
Name | Nominal composition (percentages) | Form and condition | Yield strength (0.2% offset, ksi) | Tensile strength (ksi) | Elongation in 2 inches (percent) | Hardness (Brinell scale) | Comments |
---|---|---|---|---|---|---|---|
Copper (ASTM B1, B2, B3, B152, B124, R133) | Cu 99.9 | Annealed | 10 | 32 | 45 | 42 | Electrical equipment, roofing, screens |
Cold-drawn | 40 | 45 | 15 | 90 | |||
Cold-rolled | 40 | 46 | 5 | 100 | |||
Gilding metal (ASTM B36) | Cu 95.0, Zn 5.0 | Cold-rolled | 50 | 56 | 5 | 114 | Coins, bullet jackets |
Cartridge brass (ASTM B14, B19, B36, B134, B135) | Cu 70.0, Zn 30.0 | Cold-rolled | 63 | 76 | 8 | 155 | Good for cold-working; radiators, hardware, electrical, drawn cartridge cases. |
Phosphor bronze (ASTM B103, B139, B159) | Cu 89.75, Sn 10.0, P 0.25 | Spring temper | — | 122 | 4 | 241 | High fatigue-strength and spring qualities |
Yellow or High brass (ASTM B36, B134, B135) | Cu 65.0, Zn 35.0 | Annealed | 18 | 48 | 60 | 55 | Good corrosion resistance |
Cold-drawn | 55 | 70 | 15 | 115 | |||
Cold-rolled (HT) | 60 | 74 | 10 | 180 | |||
Manganese bronze (ASTM 138) | Cu 58.5, Zn 39.2, Fe 1.0, Sn 1.0, Mn 0.3 | Annealed | 30 | 60 | 30 | 95 | Forgings |
Cold-drawn | 50 | 80 | 20 | 180 | |||
Naval brass (ASTM B21) | Cu 60.0, Zn 39.25, Sn 0.75 | Annealed | 22 | 56 | 40 | 90 | Resistance to salt corrosion |
Cold-drawn | 40 | 65 | 35 | 150 | |||
Muntz metal (ASTM B111) | Cu 60.0, Zn 40.0 | Annealed | 20 | 54 | 45 | 80 | Condensor tubes |
Aluminium bronze (ASTM B169 alloy A, B124, B150) | Cu 92.0, Al 8.0 | Annealed | 25 | 70 | 60 | 80 | — |
Hard | 65 | 105 | 7 | 210 | |||
Beryllium copper (ASTM B194, B196, B197) | Cu 97.75, Be 2.0, Co or Ni 0.25 | Annealed, solution-treated | 32 | 70 | 45 | B60 (Rockwell) | Electrical, valves, pumps, oilfield tools, aerospace landing gears, robotic welding, mold making [3] |
Cold-rolled | 104 | 110 | 5 | B81 (Rockwell) | |||
Free-cutting brass | Cu 62.0, Zn 35.5, Pb 2.5 | Cold-drawn | 44 | 70 | 18 | B80 (Rockwell) | Screws, nuts, gears, keys |
Nickel silver (ASTM B122) | Cu 65.0, Zn 17.0, Ni 18.0 | Annealed | 25 | 58 | 40 | 70 | Hardware |
Cold-rolled | 70 | 85 | 4 | 170 | |||
Nickel silver (ASTM B149) | Cu 76.5, Ni 12.5, Pb 9.0, Sn 2.0 | Cast | 18 | 35 | 15 | 55 | Easy to machine; ornaments, plumbing [4] |
Cupronickel (ASTM B111, B171) | Cu 88.35, Ni 10.0, Fe 1.25, Mn 0.4 | Annealed | 22 | 44 | 45 | – | Condensor, salt-water pipes |
Cold-drawn tube | 57 | 60 | 15 | – | |||
Cupronickel | Cu 70.0, Ni 30.0 | Wrought | – | – | – | – | Heat-exchange equipment, valves |
Ounce metal [5] Copper alloy C83600 (also known as "Red brass" or "composition metal") (ASTM B62) | Cu 85.0, Zn 5.0, Pb 5.0, Sn 5.0 | Cast | 17 | 37 | 25 | 60 | — |
Gunmetal (known as "red brass" in US) | Varies Cu 80-90%, Zn <5%, Sn ~10%, +other elements@ <1% |
Family | CDA | Tensile strength [ksi] | Yield strength [ksi] | Elongation (typ.) [%] | Hardness [Brinell 10 mm-500 kg] | Machinability [YB = 100] | ||||
---|---|---|---|---|---|---|---|---|---|---|
Min. | Typ. | Min. | Typ. | |||||||
Red brass | 833 | 32 | 10 | 35 | 35 | 35 | ||||
836 | 30 | 37 | 14 | 17 | 30 | 50–65 | 84 | |||
838 | 29 | 35 | 12 | 16 | 25 | 50–60 | 90 | |||
Semi-red brass | 844 | 29 | 34 | 13 | 15 | 26 | 50–60 | 90 | ||
848 | 25 | 36 | 12 | 14 | 30 | 50–60 | 90 | |||
Manganese bronze | 862 | 90 | 95 | 45 | 48 | 20 | 170–195† | 30 | ||
863 | 110 | 119 | 60 | 83 | 18 | 225† | 8 | |||
865 | 65 | 71 | 25 | 28 | 30 | 130† | 26 | |||
Tin bronze | 903 | 40 | 45 | 18 | 21 | 30 | 60–75 | 30 | ||
905 | 40 | 45 | 18 | 22 | 25 | 75 | 30 | |||
907 | 35 | 44 | 18 | 22 | 20 | 80 | 20 | |||
Leaded tin bronze | 922 | 34 | 40 | 16 | 20 | 30 | 60–72 | 42 | ||
923 | 36 | 40 | 16 | 20 | 25 | 60–75 | 42 | |||
926 | 40 | 44 | 18 | 20 | 30 | 65–80 | 40 | |||
927 | 35 | 42 | 21 | 20 | 77 | 45 | ||||
High-leaded tin bronze | 932 | 30 | 35 | 14 | 18 | 20 | 60–70 | 70 | ||
934 | 25 | 32 | 16 | 20 | 55–65 | 70 | ||||
935 | 25 | 32 | 12 | 16 | 30 | 55–65 | 70 | |||
936 | 33 | 30 | 16 | 21 | 15 | 79-83 | 80 | |||
937 | 25 | 35 | 12 | 18 | 20 | 55–70 | 80 | |||
938 | 25 | 30 | 14 | 16 | 18 | 50–60 | 80 | |||
943 | 21 | 27 | 13 | 10 | 42–55 | 80 | ||||
Aluminium bronze | 952 | 65 | 80 | 25 | 27 | 35 | 110–140† | 50 | ||
953 | 65 | 75 | 25 | 27 | 25 | 140† | 55 | |||
954 | 75 | 85 | 30 | 35 | 18 | 140–170† | 60 | |||
955 | 90 | 100 | 40 | 44 | 12 | 180–200† | 50 | |||
958 | 85 | 95 | 35 | 38 | 25 | 150-170† | 50 | |||
Silicon bronze | 878 | 80 | 83 | 30 | 37 | 29 | 115 | 40 | ||
† Brinell scale with 3000 kg load |
Family | CDA | ASTM | SAE | SAE superseded | Federal | Military |
---|---|---|---|---|---|---|
Red brass | 833 | |||||
836 | B145-836 | 836 | 40 | QQ-C-390 (B5) | C-2229 Gr2 | |
838 | B145-838 | 838 | QQ-C-390 (B4) | |||
Semi-red brass | 844 | B145-844 | QQ-C-390 (B2) | |||
848 | B145-848 | QQ-C-390 (B1) | ||||
Manganese bronze | 862 | B147-862 | 862 | 430A | QQ-C-390 (C4) | C-2229 Gr9 |
863 | B147-863 | 863 | 430B | QQ-C-390 (C7) | C-2229 Gr8 | |
865 | B147-865 | 865 | 43 | QQ-C-390 (C3) | C-2229 Gr7 | |
Tin bronze | 903 | B143-903 | 903 | 620 | QQ-C-390 (D5) | C-2229 Gr1 |
905 | B143-905 | 905 | 62 | QQ-C-390 (D6) | ||
907 | 907 | 65 | ||||
Leaded tin bronze | 922 | B143-922 | 922 | 622 | QQ-C-390 (D4) | B-16541 |
923 | B143-923 | 923 | 621 | QQ-C-390 (D3) | C-15345 Gr10 | |
926 | 926 | |||||
927 | 927 | 63 | ||||
High-leaded tin bronze | 932 | B144-932 | 932 | 660 | QQ-C-390 (E7) | C-15345 Gr12 |
934 | QQ-C-390 (E8) | C-22229 Gr3 | ||||
935 | B144-935 | 935 | 66 | QQ-C-390 (E9) | ||
937 | B144-937 | 937 | 64 | QQ-C-390 (E10) | ||
938 | B144-938 | 938 | 67 | QQ-C-390 (E6) | ||
943 | B144-943 | 943 | QQ-C-390 (E1) | |||
Aluminium bronze | 952 | B148-952 | 952 | 68A | QQ-C-390 (G6) | C-22229 Gr5 |
953 | B148-953 | 953 | 68B | QQ-C-390 (G7) | ||
954 | B148-954 | 954 | QQ-C-390 (G5) | C-15345 Gr13 | ||
955 | B148-955 | 955 | QQ-C-390 (G3) | C-22229 Gr8 | ||
958 | QQ-C-390 (G8) | |||||
Silicon bronze | 878 | B30 | 878 |
The following table outlines the chemical composition of various grades of copper alloys.
Family | CDA | AMS | UNS | Cu [%] | Sn [%] | Pb [%] | Zn [%] | Ni [%] | Fe [%] | Al [%] | Other [%] |
---|---|---|---|---|---|---|---|---|---|---|---|
Red brass | 833 | C83300 | 93 | 1.5 | 1.5 | 4 | |||||
C83400 [8] | 90 | 10 | |||||||||
836 | 4855B | C83600 | 85 | 5 | 5 | 5 | |||||
838 | C83800 | 83 | 4 | 6 | 7 | ||||||
Semi-red brass | 844 | C84400 | 81 | 3 | 7 | 9 | |||||
845 | C84500 | 78 | 3 | 7 | 12 | ||||||
848 | C84800 | 76 | 3 | 6 | 15 | ||||||
Manganese bronze | C86100 [9] | 67 | 0.5 | 21 | 3 | 5 | Mn 4 | ||||
862† | C86200 | 64 | 26 | 3 | 4 | Mn 3 | |||||
863† | 4862B | C86300 | 63 | 25 | 3 | 6 | Mn 3 | ||||
865 | 4860A | C86500 | 58 | 0.5 | 39.5 | 1 | 1 | Mn 0.25 | |||
Tin bronze | 903 | C90300 | 88 | 8 | 4 | ||||||
905 | 4845D | C90500 | 88 | 10 | 0.3 max | 2 | |||||
907 | C90700 | 89 | 11 | 0.5 max | 0.5 max | ||||||
Leaded tin bronze | 922 | C92200 | 88 | 6 | 1.5 | 4.5 | |||||
923 | C92300 | 87 | 8 | 1 max | 4 | ||||||
926 | 4846A | C92600 | 87 | 10 | 1 | 2 | |||||
927 | C92700 | 88 | 10 | 2 | 0.7 max | ||||||
High-leaded tin bronze | 932 | C93200 | 83 | 7 | 7 | 3 | |||||
934 | C93400 | 84 | 8 | 8 | 0.7 max | ||||||
935 | C93500 | 85 | 5 | 9 | 1 | 0.5 max | |||||
937 | 4842A | C93700 | 80 | 10 | 10 | 0.7 max | |||||
938 | C93800 | 78 | 7 | 15 | 0.75 max | ||||||
943 | 4840A | C94300 | 70 | 5 | 25 | 0.7 max | |||||
Aluminium bronze | 952 | C95200 | 88 | 3 | 9 | ||||||
953 | C95200 | 89 | 1 | 10 | |||||||
954 | 4870B 4872B | C95400 | 85 | 4 | 11 | ||||||
C95410 [10] | 85 | 4 | 11 | Ni 2 | |||||||
955 | C95500 | 81 | 4 | 4 | 11 | ||||||
C95600 [11] | 91 | 7 | Si 2 | ||||||||
C95700 [12] | 75 | 2 | 3 | 8 | Mn 12 | ||||||
958 | C95800 | 81 | 5 | 4 | 9 | Mn 1 | |||||
Silicon bronze | C87200 [13] | 89 | Si 4 | ||||||||
C87400 [14] | 83 | 14 | Si 3 | ||||||||
C87500 [15] | 82 | 14 | Si 4 | ||||||||
C87600 [16] | 90 | 5.5 | Si 4.5 | ||||||||
878 | C87800 [17] | 80 | 14 | Si 4 | |||||||
C87900 [18] | 65 | 34 | Si 1 | ||||||||
† Chemical composition may vary to yield mechanical properties |
A brass is an alloy of copper with zinc. Brasses are usually yellow in colour. The zinc content can vary between few % to about 40%; as long as it is kept under 15%, it does not markedly decrease corrosion resistance of copper.
Brasses can be sensitive to selective leaching corrosion under certain conditions, when zinc is leached from the alloy (dezincification), leaving behind a spongy copper structure.
A bronze is an alloy of copper and other metals, most often tin, but also aluminium and silicon.
Copper is often alloyed with precious metals like gold (Au) and silver (Ag).
Name | Cu [%] | Au [%] | Ag [%] | Other [%] |
---|---|---|---|---|
Auricupride | † | † | ||
Ashtadhatu | † | † | † | Fe†, Hg†, Sn†, Zn† |
Billon | † | † | Hg† | |
Chinese silver | 58 | 2 | 17.5 Zn, 11.5 Ni, | |
Corinthian bronze | † | † | † | |
CuSil | 28 | 72 | ||
Dymalloy | 20 | 80 | C (type I diamond) | |
Electrum, Green gold | 6-23 | 75-80 | 0-15 | 0-4 Cd |
Grey gold | † | † | Mn† | |
Guanín | 25 | 56 | 18 | |
Hepatizon | † | trace | trace | |
Niello | † | † | Pb sulfides† | |
Panchaloha | † | † | † | Fe†, Sn†, Pb†, Zn†, |
Rose, red, and pink gold | 20-50 | 50-75 | 0-5 | |
Spangold | 18-19 | 76 | 5-6 Al | |
Shakudō | 90-96 | 4-10 | ||
Shibuichi | 40-77 | 0-1 | 23-60 | |
Tibetan silver | † | † | Ni†, Sn† | |
Tumbaga | 3-97 | 3-97 | ||
White gold | † | † | Ni†, Zn† |
† amount unspecified
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, opacity, and luster, but may have properties that differ from those of the pure metals, such as increased strength or hardness. In some cases, an alloy may reduce the overall cost of the material while preserving important properties. In other cases, the mixture imparts synergistic properties to the constituent metal elements such as corrosion resistance or mechanical strength.
Brass is an alloy of copper (Cu) and zinc (Zn), in proportions which can be varied to achieve different colours and mechanical, electrical, acoustic, and chemical properties, but copper typically has the larger proportion. In use since prehistoric times, it is a substitutional alloy: atoms of the two constituents may replace each other within the same crystal structure.
Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals and sometimes non-metals, such as phosphorus, or metalloids such as arsenic or silicon. These additions produce a range of alloys that may be harder than copper alone, or have other useful properties, such as strength, ductility, or machinability.
Cupronickel or copper-nickel (CuNi) is an alloy of copper with nickel, usually along with small quantities of other elements added for strength, such as iron and manganese. The copper content typically varies from 60 to 90 percent.
Nickel silver, maillechort, German silver, argentan, new silver, nickel brass, albata, or alpacca is a copper alloy with nickel and often zinc. The usual formulation is 60% copper, 20% nickel and 20% zinc. Nickel silver does not contain the element silver. It is named for its silvery appearance, which can make it attractive as a cheaper and more durable substitute. It is also well suited for being plated with silver.
Brazing is a metal-joining process in which two or more metal items are joined by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal.
Tombac, or tombak, is a brass alloy with high copper content and 5–20% zinc content. Tin, lead or arsenic may be added for colouration. It is a cheap malleable alloy mainly used for medals, ornament, decoration and some munitions. In older use, the term may apply to brass alloy with a zinc content as high as 28–35%.
Plating is a finishing process in which a metal is deposited on a surface. Plating has been done for hundreds of years; it is also critical for modern technology. Plating is used to decorate objects, for corrosion inhibition, to improve solderability, to harden, to improve wearability, to reduce friction, to improve paint adhesion, to alter conductivity, to improve IR reflectivity, for radiation shielding, and for other purposes. Jewelry typically uses plating to give a silver or gold finish.
Gun metal, also known as red brass in the United States, is a type of bronze – an alloy of copper, tin, and zinc. Proportions vary but 88% copper, 8–10% tin, and 2–4% zinc is an approximation. Originally used chiefly for making guns, it has largely been replaced by steel for that purpose. Gunmetal casts and machines well, and is resistant to corrosion from steam and salt water. It is used to make steam and hydraulic castings, valves, gears, statues, and various small objects, such as buttons. It has a tensile strength of 221 megapascals (32,100 psi) to 310 megapascals (45,000 psi), a specific gravity of 8.7, a Brinell hardness of 65 to 74, and a melting point of around 1,000 degrees Celsius.
Aluminium bronze is a type of bronze in which aluminium is the main alloying metal added to copper, in contrast to standard bronze or brass. A variety of aluminium bronzes of differing compositions have found industrial use, with most ranging from 5% to 11% aluminium by weight, the remaining mass being copper; other alloying agents such as iron, nickel, manganese, and silicon are also sometimes added to aluminium bronzes.
Alloy steel is steel that is alloyed with a variety of elements in total amounts between 1.0% and 50% by weight to improve its mechanical properties.
Dip soldering is a small-scale soldering process by which electronic components are soldered to a printed circuit board (PCB) to form an electronic assembly. The solder wets to the exposed metallic areas of the board, creating a reliable mechanical and electrical connection.
Metals used for architectural purposes include lead, for water pipes, roofing, and windows; tin, formed into tinplate; zinc, copper and aluminium, in a range of applications including roofing and decoration; and iron, which has structural and other uses in the form of cast iron or wrought iron, or made into steel. Metal alloys used in building include bronze ; brass ; monel metal and nickel silver, mainly consisting of nickel and copper; and stainless steel, with important components of nickel and chromium.
C41100 Lubaloy is a wrought copper alloy that is composed mainly of copper and zinc. Lubaloy possesses many favorable characteristics making it, and other types of brass, a popular choice in manufacturing. It is a source material in many processes including the creation of electrical components and bullet-making. There are both positive and negative health effects that are associated with the use of this material.
Copper alloys are important netting materials in aquaculture. Various other materials including nylon, polyester, polypropylene, polyethylene, plastic-coated welded wire, rubber, patented twine products, and galvanized steel are also used for netting in aquaculture fish enclosures around the world. All of these materials are selected for a variety of reasons, including design feasibility, material strength, cost, and corrosion resistance.
Materials for use in vacuum are materials that show very low rates of outgassing in vacuum and, where applicable, are tolerant to bake-out temperatures. The requirements grow increasingly stringent with the desired degree of vacuum to be achieved in the vacuum chamber. The materials can produce gas by several mechanisms. Molecules of gases and water can be adsorbed on the material surface. Materials may sublimate in vacuum. Or the gases can be released from porous materials or from cracks and crevices. Traces of lubricants, residues from machining, can be present on the surfaces. A specific risk is outgassing of solvents absorbed in plastics after cleaning.
Copper has earned a respected place in the related fields of architecture, building construction, and interior design. From cathedrals to castles and from homes to offices, copper is used for a variety of architectural elements, including roofs, flashings, gutters, downspouts, domes, spires, vaults, wall cladding, and building expansion joints.
2195 aluminium alloy is an alloy in the wrought aluminium-copper family. It is one of the Weldalite family of Aluminium–lithium alloys. It is one of the most complex grades in the 2000 series, with at least 91.9% aluminium by weight. 2195 aluminium can be alternately referred to by the UNS designation A92195.
Aluminium brass is a technically rather uncommon term for high-strength and partly seawater-resistant copper-zinc cast and wrought alloys with 55–66% copper, up to 7% aluminium, up to 4.5% iron, and 5% manganese. Aluminium bronze is technically correct as bronze, a zinc-free copper-tin casting alloy with aluminium content.