The work surface and center of the bearing parts have great differences in the status, structure and performance requirements, the overall heat treatment tends to make not take into account the potential of the material are not fully realized. Applied Materials, surface enhancement technology not only solved the surface and center differences in the structure and requirements, but also further to the surface to get some special performance to meet the surface of the work under certain conditions bearing on the work performance requirements. This is very significant in the development of modern science and technology. {TodayHot}

Traditional surface hardening method, the scope of the heat treatment process. The surface of the modern development of laser, electron beam, ion beam and other enhancement methods, and some high-tech applied to the surface of the material will not only strengthen but also in the process beyond the traditional areas of heat treatment, the formation of a new technology. Surface enhancement technology from a different perspective to the formation of a variety of classification methods to strengthen the physical and chemical processes of the technology classification according to surface, can be divided into five categories: surface deformation strengthening, surface heat treatment to strengthen the chemical heat treatment to strengthen the surface of metallurgical strengthening strengthening of the surface film.

(1) the surface deformation strengthening

Plastic deformation occurs through mechanical methods of metal surface layer, thus forming a hardened layer of high hardness and high strength, the surface hardening method is called surface deformation strengthening, also known as work hardening. Including shot peening, sand blasting, cold extrusion, rolling, cold-milled and shock, blast peening. The method is characterized by: strengthening layers increased dislocation density, subgrain structure refinement, making it the hardness and strength, the surface roughness is reduced, can significantly improve the fatigue strength of parts of the surface and reduce the fatigue notch sensitivity. The fortification process is simple, the effect is significant, there are clear boundaries between the hardened layer and the substrate, a coherent structure, {HotTag} not easily fall off in use. The majority of its approach has been applied in the bearing industry: to strengthen the surface impact of the rolling body is the application of these methods, the precision RCC has become a new ferrule processing and fortification.

(2) the surface heat treatment to strengthen

The use of solid-state phase transitions, quenching parts of the surface layer by rapid heating method known as surface heat treatment, commonly known as hardening the surface. Including Flame Hardening, (center) frequency induction heating quenching, laser heating or electron beam heating quenching. The characteristics of these methods: surface local heating quenching, deformation of the workpiece is small; heating speed, high production efficiency; heating time is short and very slight surface decarburization. This method is particularly large and extra large bearing parts to withstand a certain impact load wear resistance and fatigue strength effect significantly.

(3) chemical heat treatment to strengthen

An element of solid-state diffusion infiltration, to change the chemical composition of the metal surface layer, in order to achieve surface hardening method called chemical heat treatment to strengthen, also known as the diffusion heat treatment. Including the boronizing surface alloying, carburizing and carbonitriding, nitriding and nitrogen to carbon penetration, sulfurizing Sulfur and Nitrocarburizing, chromizing, aluminizing and chrome Al-Si alloying, the graphitization layer a wide range of different characteristics. Penetrate the element or integrated into the base metal to form a solid solution, or combine to form compounds with other metallic elements. In short, the infiltration of elements can change the chemical composition of the surface layer, they can get a different phase structure. Carburizing bearing steel parts of the treatment process and needle bearing surface nitriding enhanced treatment belong to this type of fortification.

(4) surface metallurgy strengthen

The re-melting and solidification of the surface layer of metal, the surface hardening treatment technology known as surface metallurgy strengthening in order to get the desired composition or organization. Including the surface self-insoluble alloy or composite powder coating, surface melt processing of crystalline or amorphous, surface alloying, etc.. Is characterized by rapid heating to high energy density, the melting of the metal surface layer or coating on the metal surface alloying materials, and then rely on their own cooling solidified to special structure or specific performance of the strengthening layer. Perhaps this particular structure is a refinement of crystal organization, or maybe a supersaturated phase, metastable phase, and even non-crystalline organization, depending on process parameters and methods of surface metallurgy. The rolling bearing industry in the surface of miniature bearings done laser heating to strengthen the research to good effect.

Surface film to strengthen

Application of physical or chemical method, the metal surface coating on the substrate material properties different enhancement layer, called the strengthening of the surface film. It includes electroplating, electroless plating (chrome, nickel, copper, silver, etc.) and the composite plating, brush plating or conversion treatment, including high-tech rapid development in recent years: such as of CVD, PVD, P-CVD vapor deposition film to strengthen the methods and ion implantation surface hardening technology (also known as atomic metallurgical technology) and so on. Their common feature is that specific performance of the film can be formed in the work surface to strengthen the surface of the wear resistance, fatigue resistance, corrosion resistance and self-lubricating performance. Such as ion implantation technology to strengthen the bearing surface, make the bearing surface wear resistance, corrosion resistance, and resistance to contact fatigue performance have been significantly improved, so that the bearing life is to grow exponentially.


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