某航空发动机经工厂试车后,发现其球面垫圈外圆发生开裂。采用宏观观察、断口分析、能谱分析、金相检验、硬度测试等方法对该球面垫圈的开裂原因进行了分析。结果表明:该球面垫圈经氰化处理后,在磨削加工过程中,磨削温度过高导致磨削烧伤,形成黑色团状区域,该区域在快速冷却后,存在较大的残余应力,从而在该区域产生磨削裂纹,最终导致该球面垫圈发生开裂。

After the factory test run of an aero-engine, it was found that the spherical washer of the aero-engine cracked. The cracking reason of the spherical washer was analyzed by means of macroscopic observation, fracture analysis, energy spectrum analysis, metallographic examination and hardness test. The results show that after the cyanidation treatment, the grinding temperature was too high, resulting in grinding burns, forming a black ball-shaped area. After rapid cooling, there was a large residual stress in the area, resulting in grinding cracks, which eventually led to the cracking of the spherical washer.