Brass

An alloy of copper with zinc as the principal alloying element. Definition and nomenclature for copper alloys is complex, but in common use 'brass' is reserved for copper alloys with enough zinc to affect the colour, which can be detected at a level of about 5% zinc.

Occasionally, other metals such as lead may be added to produce, for example, leaded brasses. Past use of the term included copper-tin alloys now referred to as 'bronzes'. An alloy of copper 78% - 80%, zinc 20%, was called 'orichalcum' by the Romans (also the name of naturally occurring cu/au alloy in South America).

'Red brasses' comprise copper 84-86%, zinc 15%, with traces of lead and iron, used for weather stripping, plumbing pipe and radiator cores.  These have good hot and cold working properties.

'Yellow brasses' comprise copper 65%, zinc 35%; these are good for stamping, spinning and drawing.

'Cartridge brasses' comprise copper 68%, zinc 30%, with traces of lead and iron; these are used for locks, hinges, light fittings, pins and rivets.