高性能U77MnCrH钢轨材料磨损特性

Wear Characteristics of High Performance U77MnCrH Rail Material

为了明确U77MnCrH钢轨材料的耐磨损性能及磨损特征,通过摩擦磨损试验,以U75VH钢轨材料为对比对象,测试其磨损质量与磨损率,并分析转数、材料、润滑条件对磨损程度的影响。结果表明:干态下U77MnCrH的耐磨性能较U75VH提升约29%,油脂润滑剂和固态润滑剂的减磨率分别为71%和55%,油脂润滑剂的减磨效果更优;相比U75VH,U77MnCrH抗塑性变形能力更强,塑性变形层更薄且片层间的流变取向与表面的夹角更小,疲劳裂纹的出现时间更晚,裂纹扩展深度约为U75VH的20%;U77MnCrH抗加工硬化能力更强,试样表面硬度与浅表层硬度均高于U75VH;润滑条件下U77MnCrH试样加工硬化层厚度为150~200μm,小于干态条件下的250μm,润滑剂可有效缓解材料表层加工硬化程度。

In order to clarify the wear resistance and wear characteristics of U77MnCrH rail material,friction and wear tests were conducted using U75VH rail material as a comparative object to test its wear quality and wear rate.The effects of revolutions,materials,and lubrication conditions on the degree of wear were analyzed.The results show that the wear resistance of U77MnCrH in the dry state is improved by about 29%compared to U75VH,and the wear reduction rates of grease lubricant and solid lubricant are 71%and 55%,respectively.The wear reduction effect of grease lubricant is better.Compared to U75VH,U77MnCrH has stronger resistance to plastic deformation,with a thinner plastic deformation layer and a smaller angle between the rheological orientation of the layers and the surface.The occurrence time of fatigue cracks is later,and the crack propagation depth is about 20%of U75VH.U77MnCrH has stronger work hardening resistance,and the surface hardness and shallow surface hardness of the sample are higher than U75VH.The thickness of the work hardening layer of U77MnCrH sample under lubrication conditions is 150~200μm,which is less than 250μm under dry conditions.Lubricants can effectively alleviate the degree of surface work hardening of materials.