Brass

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For other uses, see Brass (disambiguation).

Template:Cleanup-date Brass is the term used for alloys of copper and zinc in a solid solution. Typically it is more than 50% copper and from 5 to 20% zinc<ref>Brasses and other Copper-Zinc Alloys, Copper Development Association, London, England. Publication No.6, </ref>, in comparison to bronze which is principally an alloy of copper and tin.<ref>Machinery Handbook, Industrial Press Inc, New York, Edition 24, page 501</ref>. Despite this distinction, some types of brasses are called bronzes.

Image:Brass.jpg Brass has a yellow colour, somewhat similar to gold. It is relatively resistant to tarnishing, and is often used as decoration.

Brass has been known to man since prehistoric times, long before zinc itself was discovered. It was produced by melting copper together with calamine, a zinc ore. During this process, the zinc is extracted from the calamine and instantly mixes with the copper. Pure zinc, on the other hand, is too reactive to be produced by ancient metalworking techniques.

1 Properties
2 Brass types
3 See also
4 External links
5 References

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Properties

The malleability and acoustic properties of brass have made it the metal of choice for brass musical instruments such as the trumpet and tuba. In organ pipes designed as "reed" pipes, brass strips are used as the "reed". It has higher malleability than copper or zinc.

In some environments, brasses with higher content of zinc are prone to a selective leaching corrosion known as dezincification. In some territories, plumbing fittings designed to resist dezincification are embossed "CR" (corrosion resistant). A dezincified fitting has the pink appearance of pure copper and will easily crumble, being reduced to a weak sponge-like matrix. Brass is a versatile manufacturing material because of its hardness and workability.

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Brass types

Admiralty brass contains 30% zinc and 1% tin which inhibits dezincification.
Alpha brasses (Prince's metal), with less than 35% zinc, are malleable, can be worked cold, and are used in pressing, forging, or similar. They contain only one phase, with face-centered cubic crystal structure.
Alpha-beta brass (Muntz metal), also called duplex brass, is 35-45 % zinc and is suited for hot working. It contains both α and β' phase; the β'-phase is body-centered cubic and is harder and stronger than α. Alpha-beta brasses are usually worked hot.
Aluminium brass contains aluminium, which improves its corrosion resistance.
Arsenical brass contains an addition of arsenic and frequently aluminium and is used for boiler fireboxes.
Beta brasses, with 45-50 % zinc content, can only be worked hot, and are harder, stronger, and suitable for casting.
Cartridge brass is a 30% zinc brass with good cold working properties.
Common brass, or rivet brass, is a 37% zinc brass, cheap and standard for cold working.
High brass, contains 65% copper and 35% zinc, has a high tensile strength and is used for springs, screws, rivets.
Leaded brass is an alpha-beta brass with an addition of lead. It has excellent machinability.
Low brass is a copper-zinc alloy containing 20% zinc with a light golden color, excellent ductility and is used for flexible metal hoses and metal bellows.
Naval brass, similar to admiralty brass, is a 40% zinc brass and 1% tin.
Red brass is an American term for CuZnSn alloy known as gunmetal.
White brass contains more than 50 % zinc and is too brittle for general use.
Yellow brass is an American term for 33% zinc brass.