Causes of clutch damping spring fracture

During the torsion durability test of a certain type of clutch driven plate assembly, its damping spring fractured. The reasons for the fracture of the spring were studied by macroscopic observation, chemical composition analysis, hardness testing, metallographic examination, scanning electron microscopy and energy spectrum analysis. The results show that there were original cracks and friction damage on the inner side of the damping spring which caused the spring to bend fatigue fracture under low stress.