First, the contact fatigue strength Bearings under the action of periodic load, the contact surface is prone to fatigue failure, that crack spalling, which is the main form of damage bearings. Therefore, in order to improve the bearing life, bearing steel must have a high contact fatigue strength. Second, the wear resistance When the bearing work, the ring, the rolling body and the cage not only between rolling friction occurs, but also occurs sliding friction, so that bearing parts continue to wear. In order to reduce the wear of bearing parts, to maintain the stability of bearing accuracy and extend the service life, bearing steel should have good wear resistance. Third, the hardness Hardness is one of the important quality of the bearing quality, contact fatigue strength, wear resistance, elastic limit has a direct impact. Bearing steel hardness in the state of use generally to achieve HRC61 ~ 65, in order to make the bearing access to higher contact fatigue strength and wear resistance. Fourth, anti-rust performance In order to prevent the bearing parts and finished products in the processing, storage and use of the process was corroded rust, requiring the bearing steel should have good anti-rust properties. Fifth, the processing performance Bearing parts in the production process, to go through many Road cold, hot processing processes, in order to meet the high volume, high efficiency, high quality requirements, bearing steel should have good processing performance. For example, cold, thermoforming performance, machinability, hardenability and the like. Bearing steel in addition to the above basic requirements, but also to achieve the appropriate chemical composition, uniform internal organization, small non-metallic inclusions, internal surface defects meet the standards and the surface decarburization layer does not exceed the required concentration requirements, these items in the raw material standards have Clear rules. Bearing parts commonly used materials are: high carbon chromium bearing steel, carburizing steel (such as 20Cr2Ni4A, 15Mn, 20Cr2MnMoA), high temperature bearing steel (such as Cr4Mo4V, Cr14Mo4, Cr15Mo4V, W18Cr4V), stainless steel bearing (9Cr18, 9Cr18Mo, 1Cr18Ni9Ti) , Vacuum degassing steel, anti-magnetic bearing steel, etc., of which the most commonly used high-carbon chromium bearing steel. The basic steels of high-carbon chromium bearing steel are GCr6, GCr9, GCr9SiMn, GCr15 and GCr15SiMn. They are the most versatile and the largest amount of steels in the bearing manufacturing industry in China, and have good wear resistance and contact fatigue performance. Ideal processing performance, with a certain degree of flexibility and toughness.