Failure Analysis on Fracture of an Air Compressor Crankshaft

Fracture failure happened to an air compressor crankshaft after running for about 5 000 h,and by means of macroscopic examination,fracture analysis,metallographic examination and hardness test,the fracture reasons for the air compressor crankshaft were analyzed.The results show that because there was serious porosity defect in the crankshaft,cracks formed at the R transitional surface porosity defect of the crankshaft,and then the cracks propagated in fatigue mode under the action of alternating stress until fracture failure.