Ball bearing steel refers to all types of work for the manufacture of various environment in the rolling bearing rings and rolling of the steel. This kind of steel chemical composition (although not complicated with about 1% carbon, chromium up to 1.65%), but because the ball bearing is working in high speed rotating and sliding conditions, great friction between each other, so the requirement with high hardness and wear resistance and uniform. Thus, the uniformity of the inside structure of steel and chemical composition, the non metallic inclusions and carbide quantity and distribution as well as the steel decarburization level, higher than other general industrial use steel have requirements. Bearing steel for high carbon chromium bearing steel, non chromium bearing steel, carburizing bearing steel, stainless steel, bearing steel and high temperature in five categories