Analysis on Fracture Reasons of Fan Shaft Core

A fan shaft core was fractured during the model test. The fracture reasons were analyzed by means of chemical composition analysis, metallographic examination, hardness testing, macroscopic and microscopic observation of fracture. The results showed that the overheating treatment to material of shaft core led to carbide precipitate out at grain boundaries, which resulted in reduction of binding force of grain boundaries. In addition, the high hardness made the brittleness of material raise, then led to brittle fracture.