不同表面状态对齿轮气体渗氮的影响OA

Through experimental investigations on the influence of different surface conditions of quenched and tempered 42CrMo gear steel on gas nitriding,the following conclusions were drawn:To simulate the surface roughness of ground gear teeth,specimens were subjected to grinding and polishing,resulting in the lower nitrided case depth and surface hardness at 0.679mm and 672.27HV0.3,respectively;Increasing the surface roughness within a certain range enhanced the nitrided case depth.At a surface roughness of 2.43μm,the case depth and surface hardness reached 0.839mm and 733.06HV0.3,representing increases of 23.6％and 8.1％,respectively,compared to the polished specimens;Subjecting polished surfaces to intensive shot peening prior to nitriding improved the nitrided case depth,achieving values of 0.79mm and 691HV0.3,corresponding to increases of 16.3％and 1.9％over the polished specimens;Acid etching the polished surfaces before nitriding significantly increased the case depth to 0.866mm(a 27.5％improvement)and the surface hardness to 752HV0.3(a 10.9％increase);Furthermore,finer and more uniform quenched and tempered microstructure,along with higher matrix hardness,contributed to greater nitrided case depth and higher surface hardness.A 14.4％increase in the matrix hardness led to improvements of 11.3％in nitrided case depth and 3.9％in surface hardness.