There are great differences between the working surface and the core of bearing parts in terms of state, structure and performance requirements, but the overall heat treatment often makes it impossible to take into account, and the potential of materials can not be brought into full play.
The metal surface layer is plastically deformed by mechanical methods to form a hardened layer with high hardness and high strength. This surface strengthening method is called surface deformation strengthening, also known as work hardening. Including shot blasting, sand blasting, cold extrusion, rolling, cold rolling and impact, explosion impact strengthening, etc. Selection and use of fag bearings
Quenching the surface layer of parts by means of solid-state phase transformation and 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, etc.Selection and use of fag bearings
The characteristics of these methods are: local heating and quenching of the surface, small deformation of the workpiece; Fast heating speed and high production efficiency; The heating time is short, and the surface oxidation decarburization is very slight.Selection and use of fag bearings
The application of material surface strengthening technology can not only better solve the differences in structure and requirements between the surface and the core, but also further make the surface obtain some special working properties to meet the requirements of the bearing working under specific conditions. This is of great significance in the development of modern science and technology.
The characteristics of these methods are: the strengthening layer dislocation density increases and the sub crystal structure is refined, so as to improve its hardness and strength and reduce the surface roughness value, which can significantly improve the surface fatigue strength of parts and reduce the sensitivity of fatigue notch. This strengthening method has the advantages of simple process and remarkable effect.
There is no obvious boundary between the hardened layer and the matrix, the structure is coherent, and it is not easy to fall off in use. Most of its methods have been applied in the bearing industry: the surface impact strengthening of rolling element is the application of this kind of method, and precision rolling has become a new ferrule processing and strengthening method.
The traditional surface strengthening method belongs to the category of heat treatment. The surface strengthening methods such as laser, electron beam and ion beam developed in modern times not only apply some high and new technologies to the surface strengthening of materials, but also go beyond the scope of traditional heat treatment and form a new technical field.
Therefore, the current surface strengthening technology can form a variety of classification methods from different angles. According to the physical and chemical process of surface strengthening technology, it can be roughly divided into five categories: surface deformation strengthening, surface heat treatment strengthening, chemical heat treatment strengthening, surface metallurgy strengthening and surface film strengthening.