关键词: SKD11钢, 脉冲磁场处理, 残余拉应力, 位错, 冲压模具

Abstract: Sevel single factor experiments were designed to explore the influence mechanism of residual tensile stress in the SKD11 steel by PMT.When the magnetic field strength, the magnetic field frequency, magnetic field direction and the processing time were varied individually,the changes of residual tensile stress in the sample were obtained.All experimental phenomena were explained from the angle of dislocation-nature of the stress. Process of PMT was divided into two stages in the explanation. The first stage was un-piling of the dislocation pile-up group and the second was multiplication of dislocation. Formula of Hp was deduced and Hp was the critical magnetic field strength which started the un-piling of dislocation pile-up group in the first stage. Formula of Hc and H'-pwere deduced. In the second stage,Hc was the critical magnetic field strength which started multiplication of a single Frank-Read dislocation source and H'-p was the critical magnetic field strength which made a single dislocation overcome the lattice resistance. The principals of PMT in the applications to stamping die were established based on the experiments and the theory.

Key words: SKD11 steel, pulse magnetic field treatment(PMT), residual tensile stress, dislocation, stamping die