Study On The Wear Resistance Of Plasma Electrolytic Carbonitriding Of42CrmMo Steel

In the system of ethanol amine solution, Plasma Electrolytic Carbonitriding(PEC/N) of42CrMo steel had been investigated in this study.42CrMo steel were optimized by the orthogonal test of liquid phase plasma carbonitriding process parameters.research on the wear resistance of total permeability layer,which was got on the optimal process conditions. Cross-section morphology of treated sample was investigated by optical microcopy, Sample surface morphology was observed by scanning electron microscope. Phase structure and elements distribution of sample were investigated by XRD and EDS. Hardness and corrosion resistance of sample detected by micro hardness tester and electrochemical workstation. The choice of the power supply determined by experimental results. Exploring the influence of working voltage> the processing time for the thickness of carbonitriding layer.Finally the Permeability layer wear resistance were detected by SEM、XRD、EDS、CLSM and Friction and wear tester.The results showed that in the system of ethanol amine solution,when adopt none-pulse DC power supply42CrMo steel can obtain carbonitriding layer by Plasma Electrolytic Carbonitriding. The carbonitriding layer thickness increases with the extension of time and rising of working voltage in a certain range. Carbonitriding layer consists of white layer, outside of white layer and diffusion layer. White layer thickness is significantly higher than that of the diffusion layer.The carbon and nitrogen atoms exist in the carbonitriding layer in the forms of iron-carbon、iron-nitrogen. Total nitrogen content in the carbonitriding layer decreased with the increase of distance from the surface. A total of carbonitriding layer of carbon in the outside white layer and diffusion layer is higher than intside white layer.The hardness of outside white layer and diffusion layer is higher than inside white layer. The highest hardness can reach651HVAt the same time the layer win the good corrosion resistance with the phase of ε-Fe (2-3) N.The corrosion current density is6.564×10-6A/cm2,which is less one order of magnitude than substrate. After dealing with the liquid phase plasma carbonitriding the roughness on the surface of the specimen increased. When sample obtained porous loose continuously bombard, the surface of the sample surface will have a high carbon and nitrogen content. Process parameters of the voltage impact on carbonitriding layer thickness is most obvious, then is the processing time, solution concentration and salt concentration. The optimal parameters for the carbonitriding layer are2%KC1、50%ethanol amine solution, the working voltage is beyond the arc voltage21v, the processing time is15min.Liquid phase plasma carbonitriding process can effectively improve the wear resistance of42CrMo steel. The wear resistance of outside white layer is superior to the wear resistance of inside white layer.