航空发动机低压轴前支点轴承内圈剥落故障分析

Failure Analysis on Peeling off of Inner Ring of Front Bearing of Aero-engine Low-pressure Shaft

航空发动机低压轴前支点轴承试车故检时发现内圈剥落。通过采用故障树分析方法对故障轴承进行失效分析,找到剥落原因。首先检测原材料化学成分,然后针对加工过程中与产生剥落有关的锻造、热处理和磨加工工序,分别对剥落内圈内部缺陷,硬度和淬回火组织,滚道表面形貌与残余应力进行检测分析,最后得出轴承剥落原因为锻造缺陷引起的疲劳剥落。通过增加锻件水浸超声检测的过程控制,可防止缺陷产品流出。

Peeling off was found to have occurred to the inner ring of the front bearing of low-pressure shaft of an aero-engine during fault detection after test. The cause for the peeling off was analyzed through fault tree. First, the chemical composition of raw material was analyzed, then the forging,heat treatment and grinding processes related to the peeling off were discussed,and the internal defects, hardness, quenching structure, surface morphology and residual stress of the inner ring were detected and analyzed. Finally, it is found that the peeling off is fatigue peeling off caused by forging defects. The outflow of defective products can be prevented by water immersion ultrasonic testing.