Bearing parts work surface and center in the state, structure and performance requirements is a greater difference, and the overall heat treatment often makes two significant not take into account the potential of the material is also not full. Applied Materials, surface hardening technology not only can solve the differences in surface and center in terms of structure and requirements, but also to further the surface to obtain some special work performance to meet the bearing surface of the work performance of work under certain conditions requirements. This modern science and technology development is very meaningful.
The traditional method of surface hardening, heat treatment within the scope of the process. The surface hardening methods for laser, electron beam, ion beam and other modern developed will not only be applied to the surface of some high-tech materials to strengthen, and in the process beyond the scope of traditional heat treatment, the formation of a new technology. So now strengthening surface multiple classification techniques can be formed from a different perspective, to strengthen the physical and chemical processes by surface techniques are classified, it can be divided into five categories: surface deformation strengthening, surface heat treatment, chemical heat strengthened, surface metallurgical strengthening surface film strengthening.
1. Surface deformation strengthening
By mechanical means of the metal surface layer of plastic deformation, thereby forming a high hardness and high strength of the hardened layer, this surface hardening method known as surface deformation strengthening, also called hardening. Including shot peening, sand blasting, cold extrusion, rolling, grinding and cold shock, explosion shock processing and the like. Characteristics of these methods are: strengthening layer increased dislocation density, subgrain structure refinement, making it the hardness and strength increased, the surface roughness value decreases, can significantly improve the surface fatigue strength of parts and reduce fatigue notch sensitivity. This intensive process is simple and the effect is significant, there are no clear boundaries between the hardening layer and the substrate, structure coherent, easy to fall off during use. Most of the methods which have been applied in the bearing industry: the surface of the rolling element is the application of these methods to strengthen the impact of precision ferrule RCC has become a new processing and fortification.
2. Surface heat strengthened
The use of solid phase transformation, by rapid heating method for parts of the surface layer hardening process called surface heat treatment, known as surface hardening. Including flame heating quenching, high (in) frequency induction heating quenching, laser heating or electron beam heating quenching. Characteristics of these methods are: local heating surface hardening, the workpiece deformation is small; heating speed, high production efficiency; heating time is short, very slight surface oxidation and decarbonization. This method especially for improving the impact load to bear certain wear resistance and fatigue strength of the effect of large and extra large bearing parts significantly.
