The so-called brake drum is a part of the drum brake system. When braking, the piston exerts pressure on two pairs of semi-moon type brake shoes, so that they are close to the inner wall of the tympanum, which creates friction to stop the wheel rotation.

Brake drum material is generally HT200-300 (gray cast iron), the matrix structure is mainly pearlite and A small amount of ferrite, cementite, graphite is mainly A class, the shape of long flake, length grade of 4-6, play the role of heat dissipation, increase friction performance, reduce brake noise.

The production process of brake drum blank is casting, and the main raw materials required are generally pig iron, scrap steel and return iron. At the same time, some alloys, such as Cu and Cr, are added to improve the casting performance.