Abstract: A catalytic cracking axial compressor unit of a certain company underwent abnormal shutdown due to the fracture of its moving blades during service. After the disassembly of the unit, the fracture surface of the blades was analyzed by using inspection methods such as macromorphology, chemical composition, microstructure, scanning electron microscopy, and energy dispersive spectroscopy. After analysis, it was found that the main cause of blade fracture was stress concentration at the corrosion pit on the outer arc surface of the blade under alternating stress, which led to fatigue crack propagation, resulting in blade fracture. By absorbing the experience and lessons learned from past cases of axial compressor blade fracture at home and abroad, corresponding measures and suggestions are proposed in such three aspects as operation management, overhaul quality and coating to preventblade fracture failure.

Key words: axial flow compressor, blade fracture, fatigue crack, corrosion