Brass
Brass is an alloy of copper and zinc containing over 50% of copper. Various proportions of copper and zinc, and the addition of other elements such as tin and lead, give brasses of different mechanical properties. In broad terms, however, brass is a soft material of lower ductility than copper, and having an ultimate tensile stress of the order of 225 m. It is readily machinable, but also is subject to work hardening, with a corresponding increase in strength and decrease in ductility. The stresses set up by work hardening may be relieved by suitable heat treatment (annealing), when the ductility will be improved again. The tensile strength may also be reduced from its work-hardened value by annealing, but to a value higher than in the pre-stressed state. Brass is also resistant to corrosion, and it can be readily soldered. It is a non-magnetic conductor, having a resistivity of about 8 m.
Brass may be used for nuts and bolts of various sizes, for bearing surfaces and in the form of castings, because it may be easily cast into complex shapes, and because it will give values of strength.