Effect of electropulsing on the fatigued heat-rolled 30CrMnSiA steel

Pre-fatigued heat-rolled 30CrMnSiA steel sample was treated by high density electropulsing, then fine and uniform equiaxed grain was obtained and grain size was much fine than that of the original sample. The fatigue life of samples was prolonged after treatment. It is supposed that the dislocations moved when suffering electropulsing, a dipole consisting of edge dislocations of opposite sign will annihilate to form a vacancy when spacing of the edge dislocations became smaller than critical spacing. The increase of the local dislocations density gradient causes the recrystallizing nucleus to be formed in the lower dislocation density regions.