Analysis of crack healing in hot rolled deformed piece
The crack healing process during hot rolling has been investigated. According to the experimental results, the crack healing process goes through four stages: crack surface contact, locally healing discontinuously, healing zone expanding, and global healing. On the basis of above results, the mechanism of crack healing is established. A new concept of crack contact depth is proposed. When the crack contact depth is less than a critical value, the continuity of crack is broken by the action of atoms near crack surfaces which might be caused by the movement of dislocation during deformation, and a local zone heals, then the healing zone expands.