Influence Of Pre-stress On Workpiece Surface Residual Stress Of Grinding Hardening

As a final step in mechanical processing, grinding is an important processing technology. The requirement of the mechanical products with the precision, the reliability and the service life improving unceasingly, the application of new materials with high hardness, high strength, high wear resistance and high performance, have put forward higher requirements for the grinding in recent years.Grinding will produce a lot of heat, and the most of them will flow into the workpiece, which will make the temperature of the grinding zone very high, even resulting in grinding burn. Local area high temperature will influence the size and distribution of the surface residual stress which could lead to the grinding cracks.Therefore, in order to be able to provide some basic research for improving the pre-stress grinding hardening, this paper used 45 steel as the material for grinding test under the pre-stress conditions, carried the residual stress simulation by using ANS YS.(1)This paper established the theoretical model for the grinding process. And the grinding temperature field has been simulated by using ANSYS with the different grinding parameters such as the grinding depth and workpiece speed. The temperature field in grinding zone was achieved. The change trend of the temperature along the surface of workpiece was forecasted.(2) Based on the ANSYS, the thermal-mechanical coupling of the surface grinding for 45 steel was simulated by writing APDL program code. The size and distribution of the surface residual stress were obtained after pre-stress grinding process. The influence of pre-stress and the other grinding parameters on surface residual stress in the workpiece was researched.(3) Based on different test conditions, this paper did the pre-stress grinding tests for 45 steel and measured the residual stress on the workpiece by using X-ray diffraction method. To verify the feasibility of the simulation, this paper compared the test data with the simulation data by using the software of MATLAB and ORIGIN.The test and simulation results showed that the surface temperature gradient is large after grinding, the grinding depth of grinding is a major factor in changing temperature, the greater the depth of grinding, the grinding temperature higher.Residual stress is tensile stress after grinding. Pre-stress could effectively reduce the surface residual stress. In the small depth of cut, compressive stress which is conducive to the workpiece occurred even in surface. The release of pre-stress after cooling the workpiece could effectively reduce residual tensile stress. Variation of residual stress is directional.Based on this paper, thermal-mechanical coupling of grinding process under the pre-stress is more suitable for a small grinding depth.