Rolling contact fatigue performance is among the most important issues for applications of bearing steels. In this work, a recently developed surface modification technique, surface mechanical rolling treatment, was applied on a rare-earth addition bearing steel. And rolling contact fatigue behavior of treated samples was compared with that of as-received counterparts at different contacting stresses. The results demonstrated that a 700 μm-thick gradient nanostructured surface layer is produced on samples by surface mechanical rolling treatment. The grain size decreases while the microhardness increases gradually with decreasing depth, reaching ∼23 nm and ∼10.2 GPa, respectively, at the top surface. Consequently, the rolling contact fatigue property is significantly enhanced. The characteristic life of treated samples is ∼3.2 times that of untreated counterparts according to Weibull curves at 5.6 GPa. Analyses of fatigue mechanisms demonstrated that the gradient nanostructured surface layer might not only retard material degradation and microcrack formation, but also prolong the steady-state elastic response stage under rolling contact fatigue.

滚动接触疲劳性能是轴承钢应用中最重要的问题之一。在这项工作中，将最近开发的表面改性技术——表面机械轧制处理应用于稀土添加轴承钢。并将处理过的样品的滚动接触疲劳行为与不同接触应力下的原始样品进行比较。结果表明，通过表面机械滚压处理，样品上产生了700 μm厚的梯度纳米结构表面层。随着深度的减小，晶粒尺寸减小，而显微硬度逐渐增大，在顶面分别达到~23 nm和~10.2 GPa。其结果，滚动疲劳特性显着提高。根据 5.6 GPa 下的威布尔曲线，经过处理的样品的特征寿命是未处理样品的 3.2 倍。疲劳机制分析表明，梯度纳米结构表面层不仅可以延缓材料降解和微裂纹形成，而且可以延长滚动接触疲劳下的稳态弹性响应阶段。