Effect of grinding temperature on grinding effect

A large number of grinding heat will soften the surface of the workpiece, so that the plastic is increased, it is conducive to the formation of wear debris. But it has adverse effects on the surface quality of the workpiece, grinding and machine tool, etc.
The influence of the workpiece is mainly manifested in two aspects: surface quality and machining precision. The high temperature will cause the surface layer of the workpiece to be changed. When the temperature does not exceed the grinding temperature of the workpiece, the changes of surface layer mainly depends on the metal plastic deformation generated by hardening and produced by grinding heat recovery effect of these two processes, the combined effects of grinding temperature can make the surface layer of cold hardening recovery; if the temperature exceeds the critical grinding the temperature of the metal workpiece, the metal plastic deformation and phase transformation may also produce metal structure.
Grinding of the instantaneous temperature is too high and concentrated in the part of the surface layer of the workpiece, the workpiece surface layer will cause local changes in the microstructure, which is called grinding burn. Burn phenomenon will cause the mechanical properties of the surface layer of the workpiece decreased, mainly to reduce the hardness and wear resistance of the workpiece. Grinding burns can be divided into two categories: the first category is the workpiece grinding temperature has not yet reached the critical temperature of the workpiece material, only to make the surface layer of the workpiece to produce tempering phenomenon, then the surface layer microstructure appears tempered layer. The second category refers to the critical temperature of the workpiece temperature exceeds the workpiece material, through the grinding zone and two quenching due to rapid cooling, the surface layer of gold tissue formed by tempered layer and two quenching Soxhlet shape, trooslite composition. The higher instantaneous grinding temperature in the grinding process and the cooling process caused great temperature difference between the surface layer of the workpiece and the parent metal, which forms a great thermal stress. If the thermal stress exceeds the strength of the material, can make the workpiece grinding cracks, especially in the cooling process, if the surface layer and the base metal has a large temperature difference, so the surface layer will form a large tensile stress, and tensile residual stress, even surface crack. The existence of cracks, even if it is very small micro crack, it will greatly reduce the fatigue strength of the workpiece, greatly shorten the life of the workpiece. From the above we can see that the main factors affecting the grinding burn is the moment when the level of grinding, the causes of grinding cracks and residual stress for gradient of ground surface layer of the workpiece, the grinding the tensile strength of the thermal conductivity of materials with low more should pay special attention to. Sometimes, in order to reduce the temperature gradient, the temperature gradient can be used to reduce the grinding temperature gradient, and the grinding crack can be prevented.
The grinding temperature causes the abrasive grains in the grinding wheel to bear the temperature stress formed by the grinding heat, which has a negative effect on the strength and wear resistance of the abrasive grains. In terms of resin bond and rubber bond, high grinding temperature can lead to carbonization of resin and rubber. The grinding temperature can also cause a strong chemical reaction in the grinding area, resulting in the ability to wear and lose the cutting quickly. High grinding temperature will make the machine used to produce hot deformation, thus affecting the accuracy of the machine tool.