The rolling contact fatigue (RCF) of both a high carbon through-hardening bearing steel (SAE52100) and a low carbon case-hardening bearing steel (SAE4320) have been investigated using RCF. The RCF-life for the SAE4320 steel was found to be ≈ 7.0 x 10⁷ cycles, about 7 times higher than the RCF-life found for the SAE52100 steel of ≈ 1.0 x 10⁷ cycles. Measurements from fracture surfaces of specimens tested to failure in rotatory bending fatigue tests revealed an average inclusion size of 27.3 μm for SAE52100, and 38.2 μm for SAE4320, indicating a lower purity for case-hardening bearing steel, and suggesting SAE4320 should have a shorter RCF-life, contrary to the measured RCF-lives. However, the carbide size, the prior austenite grain size and the retained austenite (RA) volume fraction for SAE4320 were measured as 0.20 μm, 10.8 μm and 25.0%, respectively, all of which are better than those for SAE52100 (0.59 μm, 16.1 μm and 3.1%). The enhanced RCF-life can be understood as a combined result of the detrimental effects of inclusion size and the beneficial contribution of the refined carbide and prior austenite grain size and of the increased austenite volume fraction. Based on this study, it is proposed that a double refinement of both carbide and prior austenite grain size, together with control of the austenite fraction, may be a promising way to extend RCF-life without the requirement for further inclusion refinement during the fabrication high-performance bearing steels.

使用 RCF 研究了高碳淬透轴承钢 (SAE52100) 和低碳表面硬化轴承钢 (SAE4320) 的滚动接触疲劳 (RCF)。发现 SAE4320 钢的 RCF 寿命约为 7.0  x  10 ⁷循环，比 SAE52100 钢的 RCF 寿命约为 1.0 x 10 ^{7高 7 倍}周期。在旋转弯曲疲劳试验中对试样断裂面进行的测量显示，SAE52100 的平均夹杂物尺寸为 27.3 μm，SAE4320 的平均夹杂物尺寸为 38.2 μm，表明表面硬化轴承钢的纯度较低，并表明 SAE4320 的 RCF 应该更短-life，与测量的 RCF-lives 相反。然而，SAE4320 的碳化物尺寸、原奥氏体晶粒尺寸和残余奥氏体 (RA) 体积分数分别测量为 0.20 μm、10.8 μm 和 25.0%，均优于 SAE52100 的那些（0.59 μm、16.1 μm 和 3.1%)。提高的 RCF 寿命可以理解为夹杂物尺寸的不利影响与细化碳化物和原奥氏体晶粒尺寸以及增加的奥氏体体积分数的有益贡献的综合结果。基于这项研究，