Brass is an alloy composed of copper and zinc, brass composed of copper and zinc is called ordinary brass, if it is a variety of alloys composed of more than two elements is called special brass. Brass has strong wear resistance, brass is often used in the manufacture of valves, water pipes, air-conditioning inside and outside the machine connecting pipes and radiators.
Brass has good plasticity, can withstand hot and cold processing, but α single-phase brass in forging and other hot processing prone to medium-temperature brittleness, the specific temperature range varies with the amount of Zn, generally between 200 ~ 700 ℃. Therefore, the temperature should be higher than 700℃ during hot processing.
Two-phase brass, in addition to the α-phase with good plasticity in the alloy organization, also appears by the electronic compound CuZn-based β-solid solution. β-phase has high plasticity at high temperatures, while the β′-phase (ordered solid solution) at low temperatures is hard and brittle in nature. Therefore, (α+β) brass should be forged in the hot state. β brass with zinc content greater than 46%~50% can not be pressure machined because of its hard and brittle properties.
