Control Of Grinding Surface Residual Stress And Experimental Research Of Parts’ Surface Integrity

Grinding is important in mechanical manufacturing process. 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 brought many new problems for the grinding in recent years.Grinding process needs very big energy input, and the most will flow into the workpiece in the form of heat energy, which will make the temperature of the grinding zone very high, even resulting in grinding burn. Local high temperature will influence the size and distribution of the residual stress which could lead to the grinding cracks. This paper analyzed the temperature and surface residual stress of45steel using the simulation and experiments, which had the vital significance in controlling grinding workpiece quality.(1) In this paper, the grinding temperature field has been analyzed with the finite element method firstly, then trend of surface grinding temperature field of45steel are analyzed in detailed with the grinding parameters such as the cut depth, wheel linear velocity, workpiece speed. The node’s temperature change and the temperature field in grinding zone were achieved; the changes of temperature field along the surface of workpiece and the direction of depth were forecasted.(2) Based on the3D finite element model, the thermal-mechanical coupling field of the surface grinding for45steel was simulated and analyzed in indirect way using APDL program. The size and distribution of the residual stress were obtained; the graph of the residual stresses parallel to and perpendicular to the grinding direction were achieved; the temperature’s influence on the residual stress was discussed; the measures for improving the residual stress of workpiece surface after the grinding were put forwarded.(3) Based on the different grinding conditions, the surface residual stress and hardness were tested. The influence of grinding parameters and dry-wet grinding condition on the residual stress was discussed.Comparing the simulation results and experimental results, many conclusions were obtained. A surface temperature gradient is formed. the values of temperature and residual stress are changed according to a certain rule as varying the grinding condition and parameters. These values are raised as increasing the cutting depth and the wheel linear velocity, while reduced as increasing the speed of workpiece; the cutting depth had a bigger influence than wheel linear velocity and the speed of workpiece. The tensile stresses exist near the surface of workpiece, and its values decrease gradually when the depth increases and then turn to compressive stress at a certain depth, eventually, compressive stresses become smaller as the depth increases and then tend to be a stable value. The values of residual stress are more decreased in wet grinding than dry grinding. The consistency between the simulation results and the test results validated the built model; these provide a foundation for the prediction and control of the grinding temperature and residual stress of surface grinding for45steel.