发动机减速机匣外场使用时发现异常,分解检查发现轴承套圈外滚道出现剥落,在轴承外观检查、成分分析、硬度检测、金相分析和应力测试结果基础上,对轴承剥落原因进行了分析,结果表明:轴承剥落性质为接触疲劳,轴承套圈在磨加工过程中产生的磨削力过大,滚道表面产生高温,在滚道表面形成一层薄而脆的二次淬火马氏体,并在滚道表面和次表面之间形成拉应力,滚道表面组织和性能的改变,产生磨削烧伤,降低了轴承的耐磨性和疲劳强度,导致轴承早期疲劳失效措施,并提出了采取合理的磨削参数,以及采用冷酸洗法与磁弹法相结合的预防措施.%Flaking occurred to the bearing outer rollaway nest of an engine reducer box during service. The failure cause was analyzed by appearance inspection, composition analysis, hardness testing, metallographic analysis and stress testing. The results show that the failure mode of the bearing is contact fatigue. The grinding force is too large during the grinding process of bearing ring, resulting in higher rollaway nest surface temperature. As a result, a thin layer of brittle secondary tempering martensite formed at the surface of rollaway nest, and there existed tensile stress between the surface and secondary surface of rollaway nest. Grinding burn caused the change of surface microstructure and properties of rollaway nest, which resulted in the decline of abrasion resistance and fatigue strength of bearing, and leading to earlier fatigue failure of the bearing.
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