INTERNAL CRACK RECOVERY OF 20MNMO STEEL

According to the results of physical modelling, SEM and SAM analysis o f 20MnMo steel samples, internal cracks of metal parts ate recoverable . The motive power of the recovery is atom diffusion and migration fro m matrix to voids. The recovery process consists of two steps. In the first step, the void area is filled up with a kind of metal mass, begi nning from the crack tip. There art many microvoids in the mass with d ifferent microstructure from the matrix. in the second step, microvoid s decrease in size and number, and the mass microstructure approaches the matrix, with the heating temperature increasing and the holding ti me prolonging, Recovery tests an rejected heavy forgings are successfu lly processed. It is believed that the recovers technique is a potenti al method for improving the internal quality and reducing the producti on loss and cost of metal products. Similar method can be used to trea t other metal construction parts for rescuing them or prolonging their service life. Further research and development of recovery technique have very important theoretical and practical significance.