The most commonly used copper alloys in the industrial and commercial applications are so-called brass, traditionally applied to copper-zinc alloys. In this type of alloy, the zinc content varies between 5 (brass C 210) and 40% (brass C 280). The essential distinction between different types of brasses is determined by their crystal structures, because the combination of zinc and copper is represented by peritectic solidification, making them combine in different ways depending on the content ratios and temperatures. Here are the three different types of crystal structures that can be formed as a result of these factors:
Alpha Brasses
This is still a monophasic alloy, but already has very different characteristics from the red brass, starting with its yellowish coloration. It may present decay problems, depending on the environment in which it is being used, but in compensation, it has the most favorable combination of mechanical strength and ductility among all brasses, which is why it is very suitable for forming processes in general, particularly the stamping and deep inlay. Its main application is in the manufacture of ammunition cartridges (this alloy is popularly known as "cartridge brass"), but it can also be used for a wide range of applications, such as heat exchanger tubes for non-polluted water, evaporators and automotive radiators, sanitary metals, fire extinguishers, rivets, bolts, and screws.
Alpha-Beta Brasses
This is a typical biphasic alloy that is suited for hot working, related to the presence of the beta phase, which on the other hand makes cold forming difficult. Their applications are also limited to non-corrosive environments. It has better cold forming and welding properties than the C 370 brass (61% copper, 38% zinc and 1% lead), but lower machinability. It is used in the manufacture of boards, bars, and profiles, in architecture in structured sections and thick panels, in the chemical industry in plates of condenser tubes and mechanical components manufactured by forging.
Beta Brasses
Beta brasses can only be worked hot, and are harder, stronger, and suitable for casting. The high zinc-low copper content means these are some of the brightest and least-golden of the common brasses.
