Brasses are a range of cast and wrought copper alloys made up of copper and zinc, with differing combinations of properties, including strength, machinability, ductility, wear-resistance, hardness, colour, electrical and thermal conductivity, and corrosion resistance.
Brasses with a copper content greater than 63% are the most ductile of any copper alloy and are shaped by complex cold forming operations. If the copper content is less than 63% the brasses can be extensively hot worked by rolling, extrusion, forging and stamping.
Leaded brasses set the standard by which the machinability of other materials is judged and is also available in a very wide variety of product forms and sizes to allow minimum machining to finished dimensions. Brass does not become brittle at low temperatures like mild steel, it is also non-magnetic and non-sparking.
Brass also has excellent thermal conductivity, making it a first choice for heat exchangers (radiators). Its electrical conductivity ranges from 23 to 44% that of pure copper and where the high electrical conductivity of pure copper is not required wrought or cast brass components provide a cost effective solution for electrical contacts and terminals.
Colours of brass
Brasses have a range of attractive colours, ranging from red to yellow to gold to silver. With the addition of 1% manganese, brass will weather to a chocolate brown colour. Nickel silvers will polish to a brilliant silver colour. Brasses are easy to shape and, with all these colours available, it is not surprising that architects and designers have used brasses to enhance the appearance of new and refurbished buildings, both inside and out.
The brass industry throughout the world is well organised and equipped to recycle copper alloy products at the end of their long lives and process scrap (swarf and offcuts). Making brass from new copper and zinc would be uneconomical and wasteful of raw materials so, since new brass articles are made from recycled scrap, brass is said to be sustainable. In the UK brass manufacturers use almost 100% brass scrap.