The Surface Micro Damage Research Of 40Cr Steel Pre-stressed Hardening Grinding

Grinding hardening is a new technology which integrates grinding and hardening together.It makes the surface layer of the work-piece hardened by using the grinding heat and grinding force.Pre-stressed machining can change the residual stress of surface layer of the work-piece.Pre-stressed hardening grinding is a new technology which integrates hardening grinding and pre-stressed machining together.This paper has studied the mechanism of ordinary grinding,analyzed and calculated main grinding elements,such as grinding force and grinding heat and distribution proportion.It has analyzed the hardening causes of the surface layer,researched the different effects of grinding heat and grinding force on surface hardening layer.It has proposed the grinding-force model and the heat-source model in the pre-stressed hardening grinding process,which is provided the basis of the following test conditions and the simulation parameters' selecting.This paper has studied the formation mechanism of hardening layer by pre-stressed hardening grinding experiments.The experiment choose 40Cr steel as the grinding material and selected different grinding depths,test-piece feed rates and pre-stresses.The experiment has observed the organization phase transition of cross-section by metallographic microscope.It has observed the ideal grinding hardened layer in the pre-stressed hardening grinding and has analyzed the influence of the quality of grinding hardened layer.Drilling method was used to measure the size of the surface residual stress,analysis the pre-stressed influence of the surface residual stress.This paper has used the ANSYS software to carry out the grinding temperature field simulation on the basis of the experimental and the theoretical analysis.It has obtained the distribution of the workpiece grinding temperature field.According to the temperature of its grinding and the cooling curves of the different depths,it has selected a stable load step of the grinding process as the research subjects to study the situation of its surface grinding hardened transformation.This paper has scanned the grinding hardened surface morphology with the scanning electron microscope.Combining with the experimental results of the SEM images and EDS spectrum analysis and the temperature field simulation results,it has analyzed the surface burns injury and the grinding cracks injury from the perspective of the role of grinding heat and pre-stressed influence.it has also analyzed the formation mechanism of the different types of surface burns and has proposed the leading role of the surface grinding temperature to the surface burns.The paper has studied the different factors of the surface grinding cracks and their harm of the parts used.It has discussed the pre-stressed positive impact to reduce surface grinding cracks.