Abstract: This paper takes 30WGP1600 nonoriented electrical steel as the research object and obtains the distribution characteristics of fatigue life through a large number of fatigue tests. The initiation and propagation of fatigue cracks were systematically analyzed by optical microscope and scanning electron microscope. The results showed that the fatigue crack initiation mainly occurred in the grain, grain boundary and AlN particles on the side surface or the upperlower surface of the sample. The propagation zone of fatigue cracks shows typical cleavage river pattern, and the instantaneous fracture zone shows ductile characteristics similar to single crystal. 

Key words: nonoriented electrical steel, fatigue, crack initiation, cracks propagation