Gun metal, also known as red brass in the United States, is a type of

bronze Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloid ...

– an

alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...

copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...

tin Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the ...

, and

zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...

. Proportions vary but 88% copper, 8–10% tin, and 2–4% zinc is an approximation. Originally used chiefly for making

gun A gun is a device that Propulsion, propels a projectile using pressure or explosive force. The projectiles are typically solid, but can also be pressurized liquid (e.g. in water guns or water cannon, cannons), or gas (e.g. light-gas gun). So ...

s, it has largely been replaced by

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

for that purpose. Gunmetal casts and machines well, and is resistant to corrosion from

steam Steam is water vapor, often mixed with air or an aerosol of liquid water droplets. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization. Saturated or superheated steam is inv ...

and

salt water Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish wate ...

. 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 to , a specific gravity of 8.7, a

Brinell hardness The Brinell hardness test (pronounced /brəˈnɛl/) measures the indentation hardness of materials. It determines hardness through the scale of penetration of an indenter, loaded on a material test-piece. It is one of several definitions of hard ...

of 65 to 74, and a melting point of around 1,000 degrees

Celsius The degree Celsius is the unit of temperature on the Celsius temperature scale "Celsius temperature scale, also called centigrade temperature scale, scale based on 0 ° for the melting point of water and 100 ° for the boiling point ...

Variants

*''Gunmetal ingot'' is a related alloy in which the zinc is replaced by 2% lead; this makes the alloy easier to cast but it has less strength. *''Modified gunmetal'' contains lead in addition to the zinc; it is typically composed of 86% copper, 9.5% tin, 2.5% lead, and 2% zinc. It is used for gears and bearings. *''U.S. government bronze specification G C90500'' is composed of 88% copper, 10% tin, and 2% zinc, as is British ''Admiralty gunmetal''. *''G bronze'' (or ''Copper Alloy No. C90300'') contains 88% copper, 8% tin, and 4% zinc. *''U.S. government bronze specification H'' is composed of 83% copper, 14% tin, 3% zinc, and 0.8% phosphorus. *''Red brass'' is used to produce pipes, valves, and plumbing fixtures and is considered to offer a good mixture of corrosion resistance, strength and ease of casting. It typically contains 85% copper, 5% tin, 5% lead, and 5% zinc. *''Copper Alloy C23000'', which is known as ''red brass'', contains 84–86% copper, 0.05% each iron and lead, with the balance being zinc. Gunmetal can also mean steel treated to simulate gunmetal bronze. Bushings made of this metal are used in machinery.

Other uses of gun metal

Gun money Gun money () was an issue of coins made by the forces of James II during the Williamite War in Ireland between 1689 and 1691. They were minted in base metal (copper, brass or pewter), and were designed to be redeemed for silver coins following ...

, Irish late 17th-century emergency coins, contain gunmetal, as worn and scrapped guns were used to make them; but also many other metals, in particular brass and bronze, as people donated pots and pans and other metal objects. External doors and windows of offshore rock lighthouses are often made of gunmetal due to its corrosion resistant properties.

References

{{reflist Bronze Plumbing