时间和粗糙度对4Cr5Mo2V钢离子氮化层高温磨损性能的影响  

Effect of Nitriding Time and Roughness on High Temperature Wear Property of Plasma Nitriding 4Cr5Mo2V Steel

作　　者：孙宇锋 左鹏鹏[1] 计杰[1] 吴晓春[1] SUN Yu-feng;ZUO Peng-peng;JI Jie;WU Xiao-chun(School of Materials Science and Engineering,Shanghai University,Shanghai 200072,China)

机构地区：[1]上海大学材料科学与工程学院,上海200072

出　　处：《表面技术》2021年第4期198-204,234,共8页Surface Technology

基　　金：国家重点研发计划(2016YFB0300400,2016YFB0300402)。

摘　　要：目的提高4Cr5Mo2V钢离子氮化层的高温磨损性能。方法以表面粗糙度(Ra)与氮化时间为变量,通过正交和单变量试验对4Cr5Mo2V钢进行离子氮化。使用显微硬度仪、光学显微镜、X射线衍射仪(XRD)、高温摩擦磨损试验机分别表征4Cr5Mo2V钢离子氮化层的表面硬度、显微硬度梯度、有效厚度、疏松度、物相及高温磨损性能,利用扫描电子显微镜(SEM)和光学轮廓仪对渗层微观组织及高温摩擦磨损试样的磨损体积、磨痕形貌、截面形貌进行分析。结果氮化6 h时,渗层表面硬度及有效厚度均随粗糙度增加而增大,但疏松度均在3—4级,渗层质量差且高温磨损性能不佳;氮化10 h时,离子氮化效果与氮化6 h时相反,且Ra为1.05μm的试样氮化层逐渐减薄至200μm,渗层疏松度进一步增加至5级;当氮化时间达到14 h时,Ra为0.15μm的试样获得质量最优的氮化层,其渗层有效厚度为300μm,显微硬度梯度为5级,渗层疏松度为1级,该试样在高温摩擦磨损试验下,磨损率比Ra为1.05μm的氮化试样低64%,高温磨损性能显著提高。结论随着氮化时间的增加,表面粗糙度的增大会造成4Cr5Mo2V钢离子氮化层的减薄及疏松度的增加,使其高温磨损性能变差。表面粗糙度为0.15μm的4Cr5Mo2V钢经14 h氮化后,离子氮化层质量最佳,渗层的高温磨损性能有效提高。To improve the high temperature wear performance of plasma nitriding layer of 4Cr5Mo2V steel,in this paper,the plasma nitriding of 4Cr5Mo2V steel was carried out by orthogonal and single variable experiments with surface roughness and nitriding time as variables.The surface hardness,microhardness gradient,effective thickness,porosity,phase and high temperature wear properties of plasma nitriding layer of 4Cr5Mo2V steel were characterized by microhardness test,optical microscope observation,X-ray diffraction(XRD)and high temperature friction and wear test.Scanning electron microscope(SEM)and optical profilometer were used to analyze the microstructure of the infiltration layer,the wear volume of the high temperature friction and wear samples,the wear trace morphology and the section morphology.The results showed that when nitriding time was 6 h,the surface hardness and effective thickness of the layer increased with the increase of roughness,but when the porosity was 3-4 grade,the quality of the layer was poor and the wear performance at high temperature was bad;when the nitriding time was more than 10 hours,the effect of plasma nitriding was the opposite,and the nitriding layer of the sample with roughness of 1.05μm gradually thinned to 200μm,and the porosity of the nitriding layer further increased to level 5;when the nitriding time reached 14 h,the sample with roughness of 0.15μm got the best nitriding layer.The effective thickness of the infiltrated layer was 300μm,the microhardness gradient was level 5,and the porosity of the infiltrated layer was level 1.At this time,the wear rate was 64%lower than that of the nitriding sample with the roughness of 1.05μm under the high temperature friction and wear test.The high temperature wear performance was significantly improved.With the increase of nitriding time,enlarged surface roughness will cause the plasma nitriding layer of 4Cr5Mo2V steel to thin and its porosity to increase,and its high temperature wear performance is poor.The plasma nitriding layer of 4Cr

关 键 词：4Cr5Mo2V钢 粗糙度 离子氮化 微观组织 疏松度 高温摩擦磨损性能 

分 类 号：TG156.8[金属学及工艺—热处理] TG115.58[金属学及工艺—金属学]