Ferrous Materials and Non-Ferrous Metals and Alloys 1 introduction

(2) Alfa-Betabrass:

 Contains 36 to 45% Zn and remainder is copper for hot working.

The tensile strength and ductility of brass both increase with increase in content of

Zn upto 30% zinc. With further increase in zinc content beyond 30%, the tensile strength

continues to increase upto 45% of Zn, but ductility of brasses drops significantly. β-

phase is less ductile than α-phase but it is harder and stronger.

Thus, there are various types of brasses depending upon proportion of copper and

zinc. Fundamentally brass is a binary alloy of copper with as much as 50% zinc. Various

classes of brasses such as cartridge brass, Muntzmetal leaded brass, Admirality brass,

naval brass and nickel brass depending upon the proportion of copper and zinc plus

third alloying metal are available for various uses. Suitable type of brasses can undergo

the processes of casting, hot forging, cold forging, cold rolling into sheets, drawing into

wires and extrusion for obtaining requisite special cross-section bars. The melting point

of brass varies according to its composition but most of the brasses in the common range

liquefy between temperatures of 840°C to 960°C. By adding small quantities of other

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36 Manufacturing Processes

elements, the properties of brass may be greatly affected. For example, addition of 1 to

2% zinc improves the machinability of brass. Brass has a greater strength than that of

copper but has a lower thermal and electrical conductivity. Brasses possess very good

corrosion resistance and can be easily soldered. Brasses are used in hydraulic fittings,

pump linings, utensils, bearings and bushes, etc.