1. What is bearing steel
Bearing steel, also known as high carbon chromium steel, has a carbon content of about 1% and a chromium content of 0.5% -1.65%. Bearing steel is divided into six categories: high carbon chromium bearing steel, chromium free bearing steel, carburized bearing steel, stainless bearing steel, medium and high temperature bearing steel, and anti magnetic bearing steel.
Bearing steel is a steel used to manufacture balls, rollers, and bearing rings. Bearing steel has high and uniform hardness, wear resistance, and high elastic limit. Strict requirements are placed on the uniformity of chemical composition, content and distribution of non-metallic inclusions, and distribution of carbides in bearing steel, making it one of the most stringent steel grades in all steel production. In 1976, the International Organization for Standardization (ISO) incorporated some commonly used bearing steel grades into international standards, dividing bearing steel into four categories: fully quenched bearing steel, surface hardening bearing steel, stainless bearing steel, high-temperature bearing steel, and a total of 17 steel grades.
2. Performance requirements
In order to meet the performance requirements for dynamic bearings mentioned above, the following basic performance requirements are proposed for bearing steel materials:
1) High contact fatigue strength,
2) After heat treatment, it should have high hardness or a hardness that can meet the performance requirements of bearings,
3) High wear resistance, low friction coefficient,
4) High elastic limit,
5) Good impact toughness and fracture toughness,
6) Good dimensional stability,
7) Good rust prevention performance,
8) Good cold and hot processing performance.
3. Manufacturing requirements
The content of inclusions is closely related to the oxygen content in steel. The higher the oxygen content, the more inclusions there are and the shorter the service life.
The larger the particle size and uneven distribution of inclusions and carbides, the shorter their service life, and their size and distribution are closely related to the smelting process and quality used. The main processes for producing bearing steel are continuous casting and electric furnace smelting+electric slag remelting process, and a small amount of double vacuum or multiple vacuum self consumption processes such as vacuum induction+vacuum self consumption are used to improve the quality of bearing steel.