Liu Jiapeng, Li Yingqi, Zhang Yinhua, Hu Yue, Shi Lubing, Ding Haohao, Wang Wenjian, Liu Fengshou, Zhou Shaobo, Shi Tong
Metals and Chemistry Research Institute, China Academy of Railway Sciences, Beijing 100081, China.
Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China.
Materials (Basel). 2020 Oct 20;13(20):4678. doi: 10.3390/ma13204678.
This study aims to deeply understand the effect of contact stress and slip ratio on wear performances of bainitic rail steels. The results showed that the wear loss increased as the contact stress and slip ratio increased. Based on the surface damage morphology and microstructural analyses, it revealed that the rolling contact fatigue wear mechanism played a significant role under the low slip ratio, but the dominant wear mechanism transferred to the abrasive wear at the high slip ratio. Meanwhile, the bainitic steel specifically presented worse wear resistance under the abrasive wear mode. Compared with the influence of a slip ratio, the increase in contact stress led to severer plastic flows and contributed to the propagation of cracks. In addition, the contact stress and slip ratio had the opposite effect on the friction coefficient, that is, the friction coefficient of bainitic steels behaved the inverse proportion with the contact stress, but positive proportion with the slip ratio. At last, the increase in slip ratio had more significant effect on the reduction of retained austenite (RA) than the enlargement of contact stress due to the fact that the RA would probably be removed before the martensitic transformation occurred under the abrasive wear mechanism.
本研究旨在深入了解接触应力和滑差率对贝氏体钢轨钢磨损性能的影响。结果表明，磨损损失随接触应力和滑差率的增加而增加。基于表面损伤形态和微观结构分析，结果表明，在低滑差率下，滚动接触疲劳磨损机制起主要作用，但在高滑差率下，主导磨损机制转变为磨料磨损。同时，贝氏体钢在磨料磨损模式下耐磨性特别差。与滑差率的影响相比，接触应力的增加导致更严重的塑性流动，并促使裂纹扩展。此外，接触应力和滑差率对摩擦系数有相反的影响，即贝氏体钢的摩擦系数与接触应力成反比，但与滑差率成正比。最后，由于在磨料磨损机制下，残余奥氏体（RA）可能在马氏体转变发生之前就被去除，因此滑差率的增加对残余奥氏体减少的影响比接触应力增大的影响更显著。
