航空发动机轴承剥落分析

航空发动机轴承在使用过程中出现早期剥落。采用宏观检验、化学分析、力学性能测试、金相检验、能谱等手段对轴承内滚道表面剥落原因进行了分析，结果表明:剥落轴承内圈存在锻造过烧，形成孔洞缺陷，破坏了金属连续性，降低了轴承接触疲劳强度，在交变应力的作用下，以孔洞为核心，其周围形成“蝶形”组织，产生显微裂纹向滚动接触表面扩展，形成剥落，引起轴承疲劳失效。由此提出，通过控制锻造工艺及增加锻造缺陷的检测手段来防止锻造过烧，进而提高轴承使用寿命。

Spalling Failure Analysis of Bearing in Aero Engine

Fatigue spalling occurred to a bearing of an aero engine during service. Macroscopic examination, chemical analysis, mechanical property testing, metallographic examination, energy spectrum analysis were carried out to analyze the spalling cause of bearing inner raceway. The results show that forging burning had occurred to the bearing inner ring and formed hole defects, destroying the continuity of metal and reducing the contact fatigue strength of bearing. Under the effect of alternating stress, the hole acted as the core, resulting in the butterfly structure around it. Then micro cracks initiated and expanded to the rolling contact surface, resulting in spalling and causing the fatigue failure. By controlling the forging process and increasing the forging defects detection means to prevent forging burning, the service life of the bearing can be prolonged.