某航空发动机轴承钢球失效分析

针对某航空发动机轴承钢球的表面剥落及裂纹故障,利用视频显微镜、扫描电镜等设备对故障钢球剥落表面进行宏、微观检查,明确了钢球表面剥落性质为滚动接触疲劳;通过裂纹断口分析、能谱分析及金相检查等手段,确定了钢球裂纹是在淬火过程中温度过高导致的淬火裂纹,同时钢球组织中存在带状碳化物,对淬火裂纹的产生有一定的促进作用。淬火裂纹在钢球工作过程中并未扩展,但引起钢球表面发生接触疲劳剥落。建议在钢球热处理过程中,严格控制热处理工艺参数,保证热处理温度和保温时间的稳定。

Failure Analysis of Steel Ball in Bearing for an Aeroengine

The bearing steel ball of an aeroengine was flaked and cracked. The surface was analyzed by macro and micro observation utilizing microscope, SEM etc. The damage surface was caused by contact fatigue. The quencher crack was defined by the fracture analysis, component analysis and metallographic analysis. The results show that the quenching crack formed because of the high quencher temperature. Meanwhile, the banded carbonide of the steel ball also promoted the crack initiation. The crack did not extend in the working process of the steel ball, but it resulted in the contact fatigue of the steel ball. It is suggested that the parameters should be strictly controlled during the heating treatment to guarantee the stability of the temperature and the time of heat preservation.