Fracture Analysis of Aero-engine Antisurge Lead Pipe

The gasping phenomenon occurs when the aircraft engine is flying in the air, inspection on ground shows that the engine's antisurge lead pipe is broken, and this phenomenon occurs several times. In order to find out the failure mode and cause, macro and micro observation, EDS analysis, microstructure examination and microhardness test were carried out on antisurge lead pipe. The results show that the fracture mode of antisurge lead pipe is stress corrosion cracking, following with fatigue expansion in alternating stresses, leading to failure fracture eventually. This study analyzes the fracture condition of the antisurge lead pipe, finds out the causes from the aspects of the material quality, the stress condition and the using environment. Based on the analysis results, the corresponding improvement suggestions are put forward.