A large number of application practices and life tests have shown that bearing failures are mostly due to contact surface fatigue. GB/T 24611-2020/ISO15243:2017 lists fatigue as the first of the six common failure modes of bearings, and the fracture listed in the sixth place is also called fatigue fracture due to fatigue in the formation process. Typical fatigue failures are divided into subsurface origin and surface origin. 1. The maximum contact stress of subsurface originating fatigue rolling contact occurs at a certain depth below the surface, and under the repeated action of alternating stress, a fatigue source (microcrack) is formed there. The crack source gradually expands to the surface under cyclic stress, forming an open flaky crack, which is then torn into flaky particles and peeled off from the surface, resulting in pits and pits. If there is a certain weak point or defect in the bearing steel there (common ones such as non-metallic inclusions, air gaps, and grain interfaces of coarse carbides), it will accelerate the formation of fatigue sources and the expansion of fatigue cracks, and greatly reduce the fatigue life. Subsurface-originated spalling on the rotating inner ring of deep groove ball bearings Second, surface-originated fatigue contact surfaces have damage. These damages may be original, that is, scratches and bumps formed during the manufacturing process, or they may be in use. Produced, such as hard particles in the lubricant, tiny scratches caused by the relative movement of bearing parts; there may be poor lubrication at the damage, such as poor lubricant, lubricant failure; poor lubrication state aggravates the friction between the rolling element and the raceway. The relative sliding leads to micro-cracks at the root of the asperity at the surface damage; the crack propagation causes the asperity to fall off, or form a flake-like exfoliation area. This spalling is shallow in depth and can sometimes be confused with dark gray plaques. The subsurface origin spalling that has been expanded on the static inner ring of the tapered roller bearing 3. Fatigue fracture The origin of fatigue fracture is the fatigue yield formed by the assembly stress and cyclic alternating stress caused by excessive tight fitting. Assembly stress, alternating stress and yield Once the balance between the limits is lost, fractures will occur along the axis of the ferrule, forming through-shaped cracks. In practice, most of the bearing failures in normal use are damaged as described above, that is, contact surface fatigue, and the three types of fatigue failure are subsurface origin fatigue is the most common, the bearing life calculation method recommended by ASO281 and ISO281/amd.2 is Based on subsurface origin fatigue. Commonly used anti-fatigue methods are: A. Heat treatment technology Heat treatment is a commonly used process method to improve the mechanical properties of materials. In order to adapt to the different use requirements of different material parts, it is necessary to choose different heat treatment processes, pre-heat treatment structure, quenching heating temperature, heating speed , cooling method (medium and speed), tempering temperature and time, etc. have a significant impact on mechanical properties. It is necessary to optimize and combine many heat treatment parameters to obtain the best performance suitable for use conditions, thereby prolonging the fatigue resistance of the parts. life. Build a virtual production platform for heat treatment, and promote the transformation of heat treatment technology to high-tech knowledge-intensive. The optimization of heat treatment process parameters and the development of digital heat treatment technology are important prerequisites for the realization of anti-fatigue manufacturing. B. Surface chemical heat treatment The modification effect of surface chemical heat treatment is mainly on the surface. According to different application requirements, the infiltrated chemical elements can be selected, such as quenching and tempering after carburizing to improve the surface hardness, but the workpiece distortion is not easy to control: after nitriding The formation of metal nitride can obtain higher surface hardness and wear resistance, corrosion resistance and fatigue resistance, and the workpiece distortion is small, but the efficiency is not high; the co-infiltration process makes the hardness, wear resistance, corrosion resistance, and fatigue resistance better. Excellent, and quenching distortion is less, but the hardened layer is thin, not suitable for heavy-duty workpieces. The development direction of surface chemical heat treatment is to expand the application of low-temperature chemical treatment, improve the quality of the infiltration layer, accelerate the treatment process, and develop environmentally friendly processes, composite infiltration processes and analog and digital processing technologies. C. Application of surface strengthening technology Traditional surface strengthening technology originates from the principle of cold work hardening, such as shot blasting, sand blasting, shot peening, etc., new surface strengthening technology such as laser surface hardening, laser shot peening surface hardening, ultrasonic roll hardening , chemical method surface hardening, new surface hardening technology combining various processes has been successfully applied in many fields, such as laser-shot peening process (laser shock treatment), using high-energy pulsed laser to form shock waves on the surface of parts, so that the surface material produces Compression and plastic deformation form surface residual compressive stress, thereby enhancing fatigue resistance (such as stress crack resistance, corrosion fatigue resistance, etc.). D. Surface modification technology Commonly used surface modification technologies mainly include ion implantation and surface coating. Ion implantation is a non-high temperature process without the limitations of metallurgy and equilibrium phase diagrams. Different implantation elements and doses can be selected according to different needs to obtain the desired surface properties. Such as: implanting chromium ions to enhance the corrosion resistance and fatigue resistance of the base material; implanting boron ions to enhance the wear resistance of the base material.