Cause Analysis on Fracture of a Centrifugal Fan

A centrifugal fan fractured during operation. The fracture causes of fans were analyzed by means of macro analysis, scanning electron microscope analysis, chemical composition analysis, tensile property test, metallographic examination and hardness test. The results show that fatigue crack occurred at the plug weld of cover plate and blade. In the subsequent operation, the source zone of fatigue was severely worn. With the continuous operation of the fan, the fatigue cracks propagated to the cover plate, which made the centrifugal fan finally fracture.