Fracture analysis on the 4th compressor disc of some engine

Some plane was caused fire and exploded because of the fracture of the 4th disc of the engine. In this paper, in order to give the fracture mechanism and causes of the 4th disc some observation and analysis were made, such as the visual inspection of some debris of the 4th disc, the macroscopic and microscopic observation of the fracture surface on the flange and web of the 4th disc. The corrosion pits on the web surface and at the edge of the fracture surface were analyzed by energy spectrum. The beach marks on the fracture surface were measured. The material quality of the web was also analyzed. The vibration peculiarity of the engine was tested and calculated. The fracture mechanism of the 4th compressor disc is high cycle fatigue. The microstructure, hardness, chemical composition and the web thickness of the fracture site all meet with technical requirements. The fatigue failure has no connection with the material quality. The corrosion pits at the R3 arc transition between the web and the flange induced the accident. The cracking and propagation of the 4th compressor disc are mainly related to the vibration stresses.