When we understand the bearing manufacturing process, we usually find that the bearing will harden the surface of the material, which can strengthen the bearing surface and make the surface of the bearing material beautiful and smooth. The editor mainly shares the surface hardening technology classification of bearing steel materials, which are mainly divided into five technical classifications: chemical heat treatment, surface deformation strengthening, surface heat treatment, surface metallurgical strengthening and film surface strengthening. 1. Chemical heat treatment The use of solid phase diffusion to some elements, changing the chemical composition of the metal surface layer, means strengthening chemical heat treatment in order to achieve surface strengthening, also known as thermal diffusion. Including boronizing, carburizing, carburizing and carbonitriding, nitriding and nitrocarburizing, sulfide and sulfur nitrocarburizing, chromizing, aluminum and silicon infiltration, graphitized layer, etc., varieties and characteristics. Infiltrate elements or dissolve into matrix metals to form solid solutions, or form compounds with other metal elements. In short chemical composition, the elements of the surface layer can be changed and different phase structures can be obtained. Carburizing bearing steel reinforcement process and Timken imported needle roller bearing sleeve surface this reinforcement method is nitriding. 2. Surface deformation strengthening The metal surface layer is mechanically and plastically deformed to form a hardened layer with high hardness and high strength. The method of surface strengthening is called enhanced surface deformation, also known as work hardening. Including shot peening, sand blasting, cold extrusion, rolling, rolling and impact, blast impact, etc. These methods are characterized by increased dislocation density, substructure refinement, increased hardness and strength, and reduced surface roughness, which can significantly improve the surface fatigue strength of parts and reduce fatigue notch sensitivity. This reinforcement method has the advantages of simple process, remarkable effect, there is no obvious boundary between the hardened layer and the matrix structure, and it is not easy to fall off, and it is easy to use. Many methods have been applied to the imported bearing industry: the method of surface impact strengthening of this rolling element, precision rolling into a new reinforcement method for ring processing. 3. Surface heat treatment Using solid-state phase transformation, the quenching treatment of parts is called surface heat treatment, and the surface layer is rapidly heated, commonly known as surface hardening. Including flame quenching, high (medium) high frequency induction heating quenching, laser heating or electron beam heating quenching. The characteristics of these methods are: local quenching of the surface, small deformation of the workpiece; fast heating speed, high production efficiency; short heating time, very slight surface oxidation and decarburization. The method is especially used to improve the wear resistance and fatigue strength of large and super large imported bearing parts under the action of obvious impact load. 4. Surface metallurgical strengthening The melting and solidification of the metal surface layer, in order to obtain the composition of the intended surface strengthening technology or the surface metallurgical strengthening of the structure. Including surface self-dissolving alloy or composite powder coating, surface melting crystallization or amorphous treatment, and surface alloying methods. Rapid heating with high energy density, the metal surface layer or coating alloy material melts the metal surface, followed by enhanced cooling and solidification to obtain special structures or specific properties. This particular structure or refinement of the crystal structure may also be a supersaturation phase, a metastable phase, or even an amorphous structure, depending on the process parameters and surface metallurgical methods. Research on laser heating surface strengthening of rolling work in the imported bearing industry of miniature imported bearings, good results. 5. Membrane surface strengthening Using physical or chemical methods, the coating on the metal surface has different properties of the reinforced layer of the substrate material, known as the enhanced surface film. It includes electroplating, electroless plating (chrome, nickel, copper, silver, etc.) Strengthening methods and ion implantation surface strengthening technology (also known as atomic metallurgy technology), etc. Their common feature is that the film can form specific properties on the working surface, which improves the surface’s wear resistance, fatigue resistance, corrosion resistance and self-lubricating properties. For example, the surface strengthening technology of ion implantation imported bearings can significantly improve the wear resistance, corrosion resistance and contact fatigue resistance of imported bearing surfaces, and double the life of imported bearings.  

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