文摘
Pre-stressed hardening grinding (PSHG) which blends the principle of pre-stressed machining and grinding hardening technology is a complicated thermal-mechanical coupling process. As the main indexes of surface integrity, residual stress and surface roughness have an important effect on the functional performance of workpiece. In order to reveal the effect mechanisms of pre-stress on residual stress and surface roughness, simulations and experiments are carried out for 45 steel. The simulations of PSHG process are carried out in DEFORM-3D with a single grain. The effects of pre-stress on grinding force, pile-up deformation, and plastic deformation of the machined surface layer are discussed. PSHG experiments are conducted under different pre-stresses. Then, metallographic structure and surface micro-topography are observed and discussed. Combining results of the simulations and the experiments, the effect mechanisms of pre-stress on residual stress and surface roughness are analyzed. Main results of this study are as follows: the pre-stress cannot change the average of grinding force directly, but has effect on the plastic deformation and phase transformation by affecting stress-strain and temperature in PSHG, and consequently has effect on residual stress. Besides, when releasing pre-stress, core materials have elastic recovery which results in additional compressive residual stress on surface. The pre-stress affects surface roughness by affecting pile-up deformation, dislocation density and grain volume, and surface damages.
