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以双真空冶炼Cr-Ni-Mo轴承钢为研究材料,研究其渗碳后的旋转弯曲疲劳性能,分析了渗碳层厚度、硬度分布,探究了疲劳断裂方式与机理。研究表明:渗碳后,有效渗层厚度为1.60 mm,渗层碳化物分布均匀,从表层到心部,钢的硬度由727降至458 HV。本次试验的疲劳起裂方式主要是表面起裂及次表层非金属夹杂物起裂,通过降低钢的表面粗糙度可以提高疲劳性能;1000 MPa应力水平下近表面临界夹杂物尺寸为16μm。
The double-vacuum smelting Cr-Ni-Mo bearing steel was used as the research material to study the rotating bending fatigue properties after carburizing. The thickness and hardness distribution of the carburized layer were analyzed, and the fatigue fracture mode and mechanism were explored. The results show that after carburizing, the effective layer thickness is 1.60 mm, and the distribution of carbides is uniform. From the surface to the heart, the hardness of the steel decreases from 727 to 458 HV. The fatigue initiation mode of this test is mainly surface initiation and sub-surface non-metallic inclusions. The fatigue properties can be improved by reducing the surface roughness of steel. The critical inclusions near the surface at 1000 MPa stress are 16 μm.