滑差对贝氏体钢轨材料磨损行为的影响

通过对磨试验研究接触应力相同时贝氏体钢轨的磨损率、表面粗糙度、硬度,并结合扫描电镜观测到的磨损表面和剖面的形貌特征,分析不同滑差条件下贝氏体钢轨的磨损行为特征和变化规律.结果表明:接触应力为500 MPa条件下,贝氏体钢轨磨损率随滑差的增大而显著增大,滑差由2%增大到10%时磨损率增大了8倍;小滑差条件下的贝氏体钢轨表面较光滑,有少量疲劳裂纹,以滚动接触疲劳磨损为主;大滑差条件下表面粗糙,有疲劳裂纹、剥落坑和表面划擦痕迹,更接近滑动磨损;增大滑差可导致磨损表面加工硬化率偏大;增大滑差对贝氏体钢轨表面的滚动接触疲劳裂纹在深度方向的扩展几乎无影响,且对塑性变形层厚度影响不明显;大滑差可引发亚表面次表层裂纹.

Influence of Slip Ratio on Wear Performance of Bainitic Material

The wear rate,surface roughness and hardness of the bainitic rail under the same contact stress were studied through the wear test,the morphology characteristics of wear surface and profile were observed by combined with scanning electron microscope,and the wear behavior characteristics and change rule of bainitic rail under various slip ratio conditions were analyzed.The results show that when the contact stress is 500 MPa,the wear rate of bainitic rail increases significantly with the increase of slip ratio,and the wear rate increases 8 times when the slip ratio increases from 2%to 10%.Under the condition of small slip ratio,the surface of bainitic rail is smooth with a small amount of fatigue cracks,which is mainly rolling contact fatigue wear.Under the condition of large slip ratio,the surface is rough with fatigue cracks,peeling pits and surface friction marks,which is closer to sliding wear.Increasing slip ratio leads to the work hardening rate of the wear surface higher.The increase of slip ratio has little effect on the propagation of rolling contact fatigue crack on the surface of bainitic rail in the depth direction,and has no obvious effect on the thickness of plastic deformation layer,and the large slip ratio can cause subsurface cracks.