Brass is a copper-zinc alloy. It is necessary to differentiate between binary brasses, made up only of copper and zinc and triples which contain a third element which characterises the alloy. Considering the binary brasses, one speaks of an α phase when the contents of the Zn is lower than 36% approximately, the crystalline structure of the alloy depends on the copper, or is a face-centred, cubic structure. These brasses have an excellent mallability in the cold (stretched and moulded) and are good in the cold. The brasses α-β (where the β phase is body centred cubic) have an oscillating zinc title between 36 and 45 %, which work well in heat.

In the machine tools, the binary alloys copper-zincs has a good mallability, but the hardness provokes the formation of very long metal shavings, so by adding lead which is insoluble and far removed from the crystalline structure, when dispersed in the grain borders, results in shorter or powdery shavings so the tools have to suffer less wear and less overheating which contribute to improving the quality and speed of the job. The brass lead is also known as leaded brasses.

The lead brasses (CuZn38Pb2, CuZn39Pb2 and CuZn40Pb2 are the most common) are used for parts which work with the lathe, such as valves and taps. The alloy CuZn36Pb3 (‘free-cutting brass’) is used as reference for the processing and extraction of valves, with a conventional index equivalent to 100; all the other copper alloys have a lower value.
The brasses are so widely used that it was only possible to make a short list.

Electrical devices, electrics, interrupters, contacts, lamp holder
Auto transport
Radiators, electrical installation
Marine sector
Mixers, sheets
Metal sanitary ware
Taps, valves, radiators, pipes
Chemical Industry
Mechanical Industry
Nuts, screws, gears, small metal parts
Buildings and decoration
Doors, windows, furniture parts, handles
and similar
Coins, metal sheets, medals, decorations


Properties Value
Melting temperature


Specific heat

0,094 kcal/Kg

Specific heat

8,4 – 8,7 g/cm3

Thermal conductivity

96 Kcal/m°C

Electrical conductivity

0,064 Ω/mm2m

Flexural modulus of elasticity

100000 N/mm2

Coefficient of linear thermal expansion

0,0107 mm/m/°C

Tensile strength at break
210 N/mm2
Anti Corrosive