Basic requirements for steel for rolling bearings

First, contact fatigue strength

Under the action of cyclic load, the bearing surface is prone to fatigue failure, that is, cracking and spalling, which is the main damage form of the bearing. Therefore, in order to improve the service life of the bearing, the bearing steel must have a high contact fatigue strength.

Second, wear resistance

When the bearing is in operation, not only rolling friction occurs between the ferrule, the rolling element and the cage, but also sliding friction occurs, so that the bearing parts are continuously worn. In order to reduce the wear of bearing parts, maintain the bearing accuracy and stability, and extend the service life, the bearing steel should have good wear resistance.

Third, the hardness

Hardness is one of the important qualities of bearing quality and has a direct impact on contact fatigue strength, wear resistance and elastic limit. The hardness of the bearing steel in the use state generally reaches HRC61~65, in order to obtain high contact fatigue strength and wear resistance of the bearing.

Fourth, anti-rust performance

In order to prevent corrosion and rust of bearing parts and finished products during processing, storage and use, bearing steels are required to have good rust prevention performance.

Fifth, processing performance

In the production process, the bearing parts have to go through many cold and hot processing steps. In order to meet the requirements of high volume, high efficiency and high quality, the bearing steel should have good processing performance. For example, cold, thermoforming properties, machinability, hardenability, and the like.

In addition to the above basic requirements, bearing steel should also meet the requirements of proper chemical composition, uniform internal organization, less non-metallic inclusions, internal surface defects meeting the standard and surface decarburization layer not exceeding the specified concentration. These items are all in the raw material standards. Clear regulations.

Commonly used materials for bearing parts are: high carbon chromium bearing steel, carburized steel (such as 20Cr2Ni4A, 15Mn, 20Cr2MnMoA), high temperature bearing steel (such as Cr4Mo4V, Cr14Mo4, Cr15Mo4V, W18Cr4V), stainless bearing steel (9Cr18, 9Cr18Mo, 1Cr18Ni9Ti) , vacuum degassing steel, anti-magnetic bearing steel, etc., the most commonly used is high carbon chromium bearing steel. The basic steel grades of high carbon chromium bearing steels are GCr6, GCr9, GCr9SiMn, GCr15, GCr15SiMn. It is the most widely used and most used steel in the bearing manufacturing industry in China. It has good wear resistance and contact fatigue performance. Ideal processing performance with a certain degree of flexibility and toughness.