Gunmetal
Gunmetal, 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 Originally used mainly for making guns, it has largely been replaced by steel for that purpose. Handheld firearms such as muskets and pistols were historically mostly made of cast iron, and then steel, while cannons and similar mounted firearms were made of bronze until at least the mid-19th century.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.
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