Research Of Hardening Layer And Tribological Properties Of Pre-stressed Grinding

Pre-stressed grinding hardening technology is a technology which, under certain conditions prestressing, uses the coupling effect of the heat and force generated in the grinding process to harden a certain depth range of the workpiece surface.This paper, based on research of the mechanism of plane grinding, has studied main grinding elements during grinding process, for example,the contace arc length, the number of efficient grinding wheel, grind force and grinding heat partition. Based on in-depth analysis of the causes of grinding hardening, a mathematical model was established to calculate the depth of grinding hardening.This paper has studied pre-stressed grinding hardening by experiments. In the experiments, chosing 45 steel as the specimens material and changing the conditions of pre-stressed and the grinding depth without grinding liquid. After that, measuring the hardness of the surface and the depth-direction of the specimens, and obtained the microstructure of harden layer through a microscope. After deeply analyzing the result, it is clear about the infulence of pre-stressed and grinding depth on the surface mechanical properties of the hardening layer.Based on the grinding temperature finite element, calculating the heat source distributing in the grinding arc region during the grinding process through the mathematical model of grinding force and heat source distributing. According to the grinding temperature finite element simulation of the ANSYS, getting the surface theperature distribution during the grinding process, than calculating the hardness and thickness of the specimen grinding hardened layer.Tribology is a subject about friction,wear and lubrication.For studying tribological properties of the grinding hardening layer of specimen, the next experiment is the high speed reciprocating frlctional wear test, and measuring the shape and depth of millcourse and the loss caused by friction. After deeply analyzing the result, it is clear the effect of pro-stressing on the tribological properties of grinding hardening specimen.The privious studies proved that for different grinding depth, at the same time keep the other grinding parameters invariability, as the grinding depth increasing, the hardness and thickness of grinding hardening layer and the wear resisitance also has increased. For different pre-stressing, there are also some changes, but not very significantly.The grinding heat and the cooling rate is the main reason to harden the specimen surface by the phase transition. The stress-strain field generated by the prestressing and the grinding force also have an effect on the mechanical properties of the grinding hardening layer, but less affected.