Grinding Hardened Layer Of Residual Stress Finite Element Analysis

The grinding hardening is a new integrated machining technology which utilizes grinding heat to quench the non-quenched steel directly. As an indicator of measuring hardening layer's quality, the research on residual stresses is of great importance to control the hardening layer's quality effectively and to advance the development and application of the technology. This paper analyzes temperature field and stresses field in grinding using the Finite Element Method (FEM).Firstly, proceed experiments of measuring grinding force, depth of hardening layer and residual stresses, then, analyze the influence of grinding parameters on grinding force and depth of hardening layer. The results show that tangential grinding force and normal grinding force increase when grinding depth and workpiece speed increase and decrease when wheel speed increases. Depth of hardening layer increases when grinding depth and wheel speed increase and decrease when workpiece speed increases. The influence of grinding depth on grinding force and depth of hardening layer is much larger than workpiece speed and wheel speed.The change trend of residual stresses in the depth direction is achieved using X-ray diffraction method and corrosion stripping method. Grinding hardening leads to compressive residual stresses near the surface and numerical value fluctuates between a small extent. The change from compressive to tensile at the martensite-nonmartensite interface is very rapid. Under non-martensite layer, tensile residual stresses exist.Secondly, the finite element software, ANSYS, was used to simulate temperature field. Temperature field of workpieces and each node's temperature change course are achieved. Comparison of hardening layer depth between experiment of measuring rigidity and numerical simulation validates the model of temperature field. Discuss the influence of grinding parameters on maximum temperature via cross experiment method. Maximum temperature increases when grinding depth and wheel speed increase and decreases when workpiece speed increases. The influence of grinding depth on maximum temperature is much larger than workpiece speed and wheel speed.Thirdly, work out APDL program of simulating thermal stresses and stresses induced by coupling of thermal and mechanical deformation. Residual stresses and change trend of stresses in the depth direction are achieved. The results show that tensile residual stresses exist near the surface. Numerical value of tensile stresses decrease gradually when the depth increases and turn to compressive stresses at a certain depth. When the depth increases more, numerical value of compressive stresses decrease gradually and approach zero.Lastly, simulate residual stresses induced by coupling of thermal deformation, mechanical deformation and phase transformation using GUI and APDL. Change trend of stresses in the depth direction achieved by numerical simulation is consistent with experiment results, which proves the validity of the theoretic calculation model. Analyze the influence of grinding parameters on residual stresses. Numerical value of compressive stresses decreases when grinding depth and wheel speed increase and increases when workpiece speed increases.