某发动机在工作过程中连续发生3起油管漏油事故, 通过对其中一根油管上的裂纹进行宏观观察、金相检验、化学成分分析以及应力测定, 并打开裂纹进行断口电镜观察, 确定了裂纹的性质及油管开裂的原因。结果表明: 油管上的裂纹性质为起始应力较大的疲劳裂纹, 疲劳裂纹起源于油管转接嘴的R外表面, 油管的装配应力较大是导致疲劳裂纹萌生的主要原因, 高压燃油冲击和油管本身的振动对裂纹的萌生也有一定的影响,管接嘴处焊料局部未焊合对裂纹的萌生有一定的促进作用。

The oil leakage accidents occurred three times in one aviation engine in use. Based on crack macroscopic observation, metallographic examination, chemical composition analysis, stress measurement and fracture surface electron microscope observation for one of the oil tubes, the crack mechanism and cause were determined. The results showed that the cracks in oil tube were fatigue crack under large initial stress, the fatigue crack originated on the R outer surface of pipeline transfer mouth because of large assembly stress. The crack initiation also had certain effect and promoting by the impact of high pressure fuel and the vibration of tubing role and local unbonding of solder in the position of pipeline transfer mouth.