U71MnK钢轨焊缝滚动接触磨损性能研究

Wear Property of U71MnK Rail Weld under Rolling Contact

对U71Mn K钢轨焊缝及母材在滚动接触疲劳条件下进行模拟试验,对比研究了钢轨焊缝及母材在滚动接触过程中的材料磨损演变行为.结果表明:以U71Mn K为基材的钢轨焊缝部位与非焊缝部位的磨损性能及组织结构在磨损前后均存在显著差异.由于组织结构和力学性能的差异,焊缝区硬度低于非焊缝区,焊缝区摩擦系数、磨损量、磨损率均大于非焊缝区.与非焊缝区相比,钢轨焊缝区容易产生犁沟乃至波磨,表面粗糙度增大,剥落损伤、裂纹、塑性变形严重,磨损性能变坏.无论焊缝区还是非焊缝区,其先前的磨损细化了组织,改善了其磨损性能,减弱了其后的摩擦损伤.

The material wear and the evolution of the rail weld and base material in the process of rolling contact were investigated through the simulated experiments. The results show that there were significant differences between the weld and the non- weld before and after wear. Due to the differences in microstructure and mechanical properties,the hardness of the weld zone was lower than that of the non- weld zone. The friction coefficient,wear mass and wear rate of the weld zone were greater than that of the non- weld zone. Compared with the non- weld zone,the furrows and corrugations were prone to generate in the weld zone. Moreover,surface roughness increased. Spalling damage,cracks,plastic deformation aggravated and abrasion performance deteriorated in the weld zone. The previous microstructure both in the weld zone and the non-weld zone was refined by the previous wearing,which resulted in improved wear resistance. Thus,the abrasion damage reduced in the subsequent rolling contact.