Brass is an alloy of copper and zinc. The simplest brass is a binary copper-zinc alloy, called simple brass or ordinary brass. Alloys composed of two or more elements are called special brass. Based on the different alloying elements contained in the brass, it is divided into ordinary brass and special brass. Changing the zinc content in brass can produce brass with different mechanical properties. The higher the zinc content, the higher the strength, but the slightly lower the ductility. Industrially used brass has a zinc content of no more than 45%; higher zinc content will cause brittleness and deteriorate the alloy's properties.
To improve certain properties of brass, other alloying elements are added to the basic copper-zinc alloy; this is called special brass. Commonly used alloying elements include silicon, aluminum, tin, lead, manganese, iron, and nickel. The purpose of adding alloying elements is mainly to improve tensile strength and processability. The designation is "H + main alloying element symbol (except zinc) + copper mass fraction + main alloying element mass fraction + other element mass fraction". Adding aluminum to brass increases its yield strength and corrosion resistance, while slightly reducing its plasticity. Brass containing less than 4% aluminum exhibits excellent overall performance in machining and casting. Adding 1% tin to brass significantly improves its resistance to seawater and marine atmospheric corrosion, hence the name "naval brass." Tin also improves brass's machinability. Adding lead to brass primarily aims to improve machinability and wear resistance; lead has little effect on brass's strength. Nickel brass is a brass alloy containing nickel, possessing good corrosion resistance and mechanical properties.
