1. Medium frequency quenching strengthens the surface deformation of bearing steel

 The metal surface layer is plastically deformed by a mechanical method to form a hardened layer of high hardness and high strength. This surface strengthening method is called surface deformation strengthening, which is also called work hardening. Including shot peening, sand blasting, cold extrusion, rolling, cold rolling and impact, explosion shock strengthening. The characteristics of these methods are: increased dislocation density of the strengthening layer, refinement of the subgrain structure, thereby increasing the hardness and strength, and reducing the surface roughness value, which can significantly improve the surface fatigue strength of the part and reduce the sensitivity of the fatigue gap. The strengthening method is simple in process and remarkable in effect, and there is no obvious boundary between the hardened layer and the matrix, the structure is continuous, and it is not easy to fall off during use.

2. Surface heat treatment strengthening of bearing steel by medium frequency quenching

 The use of solid phase transformation, the quenching treatment of the surface layer of the part by rapid heating is called surface heat treatment, commonly known as surface quenching. Including flame heating quenching, high (medium) frequency induction heating quenching, laser heating or electron beam heating quenching. The characteristics of these methods are: local surface heating and quenching, small deformation of the workpiece; fast heating speed, high production efficiency; short heating time, surface oxidative decarburization is very slight. This method is particularly effective in improving the wear resistance and fatigue strength of large and extra large bearing parts subjected to a certain impact load.