Analysis Of Characteristics Of Micro-surface Layer 40Cr Pre-stressed Hardening Grinding

Hardening grinding technolog combines grinding with quenching together,which can be achieved through dry grinding.Dry hardening grinding technology u use the large amount of heat during the grinding process to reach the status of quenching,which has the advantage of high efficiency,environmental protection and green features.Pre-stressed hardening grinding can control residual stress through exerting a certain stress before dry grinding.This technology can control and improve the quality of the workpiece surface more effectively.This paper studies the grinding mechanism.Grinding parameters such as contact arc length,grinding force,grinding heat and heat distribution ratio were studied and analyzed.The parameters such as contact length of grinding surface in the process of pre-stress grinding hardening are determined,and the grinding force model and heat source model are put forward to provide the basis for the experimental conditions and simulation parameters selection.In this paper,40Cr is chosen as the experimental material which put into the pre-stressed experiment.The experiment studies different parameters of 40Cr parts hardened layer.By changing the depth of the grinding and the value of the pre-stress,multiple sets of experiments were carried out.The effect of grinding depth and prestress value changes on the micro-structure and the thickness of the hardened layer was investigated.The influence mechanism was also analyzed.The hardness of the surface hardened layer of the workpiece after dry grinding was measured.The effects of grinding depth and prestress on the hardness of the surface hardened layer were studied,and the influence mechanism was also analyzed.During the dry grinding process,the impact of the grinding wheel on the surface of the hardened layer is very serious and needed to be taken into consideration.On the basis of theoretical analysis and experiment,DEFORM-3 D software was used to simulate the surface hardening of parts.The equivalent stress and the equivalent strain rate of the part are analyzed under the condition of different grinding depths and different pre-stress value.And the influence mechanism is also analyzed.And the thickness of the hardened layer was estimated through the equivalent stress at different depths.The results show that the mechanical properties of the hardened layer can be improved by the application of pre-stress.As the depth of grinding increases,the hardness and depth of the hardened layer are increased.As pre-stress increases in a certain range,the thickness of the hardened layer decreased slightly.But pre-stress can make the surface of the micro-structure becomes more compact.