Based on the working environment and damage analysis of bearing steel, bearing steel needs to have the following properties:
1. High contact fatigue strength and compressive strength;
2. Bearing steel must have high and uniform hardness after heat treatment (general bearing steel hardness requirements for HRC61~65);
3. High elastic limit to prevent excessive plastic deformation of bearing steel under high load;
4. Certain toughness to prevent bearing damage under impact load;
5. Good dimensional stability, prevent bearing in long-term storage or use due to size changes and reduced accuracy;
6. Certain corrosion resistance, in the atmosphere and lubricant should not be easy to rust or corrosion, keep the surface luster;
7. Good process performance, such as cold, hot forming performance, cutting performance, grinding performance, heat treatment process performance and so on, in order to adapt to large quantities, high efficiency, high quality production needs. There are different requirements for bearings under special working conditions. Such as high temperature resistance, corrosion resistance, impact resistance, antimagnetic and so on.
The contact fatigue life of bearings is particularly sensitive to the inhomogeneity of the structure and properties of steel. Therefore, a series of requirements are proposed for the organization in use and the original organization. The microstructure of bearing steel in service condition should be evenly distributed with fine carbide on tempered martensite matrix. Such microstructure can give bearing steel the required properties. There are two main requirements for the original structure: one is pure, refers to the content of impurity elements and inclusions in steel to be less; The second is uniform structure, which means that the non-metallic inclusions and carbides in steel should be fine dispersed and evenly distributed. So the purity of steel and the uniformity of structure are the two main problems of the metallurgical quality of bearing steel.
Post time: Mar-22-2023