Cause Analysis on Fracture of Drive Shaft of an Electric Pump

Early fracture occurred in the drive shaft of an electric pump during operation. Fracture analysis, metallographic examination, hardness test, chemical composition analysis, surface quality inspection and other methods were used to analyze the fracture causes of the drive shaft. The results show that the fracture mode of the drive shaft was fatigue fracture. Due to the improper setting of electric discharge machining (EDM) technology, micro cracks generated on the pinhole surface of the drive shaft, and the micro cracks propagated continuously until the drive shaft fractured under the action of alternating load.