Mill ball can be divided into two types: forging steel balls and casting steel balls, according to the manufacturing operation. Compared to casting steel balls, forging steel balls has some priorities:

　　1) smooth surface: forging process, no defects on the surface, no deformation, keeping circle and good effect of ore grinding all the way.

　　2) tight internal structure: made by forged steel to avoid defects caused from casting process, high internal dense and fine granularity, enhance the falling times and impact toughness of ball mill ball, so reducing the breakage rate of ball mill ball.

　　3) Both for dry and wet ball mill: alloying elements with reasonable proportion, adding rare elements, controlling content of chrome, improving decay resistance greatly. In view of the fact that most mines using wet milling usually, forged steel ball is better for their mines' condition.

　　In general, casting steel ball is kind of heat-resisting ball, used for dry mill with diameter of 1.5 m- 3.8 m, in cement plant; forged steel ball is kind of corrosion-resisting ball, used for wet mill with diameter of 1.5 m- 11 m, in iron ore, gold ore, power station, etc.