Brass is a copper alloy composed of copper and zinc, which is divided into ordinary brass and special brass. Ordinary brass: it is a Cu Zn binary alloy, represented by "H", and the number after H indicates the average copper content of the alloy. For example, H70 indicates that the copper content is 70%, and the rest is zinc. Special brass: add a small amount of lead, tin, aluminum, manganese, etc. to Cu Zn gold to form a multicomponent alloy.