Microstructure and texture evolution of nonoriented silicon steel during the punching process

The iron core of a motor is mainly manufactured from rolled nonoriented silicon steel using a punching process that leads to deformation and texture evolution at the cutting edge. According to this process, circular samples of nonoriented silicon steel were prepared by punching using blunt punch tools. In this work, two positions along the rolling and transverse directions at the cutting edge were analyzed. The main mechanisms of deformation for both positions are dislocation slip and formation of shear bands. These two mechanisms lead to similar texture evolutions for both positions. The dislocation slip leads to the formation of the {221} 〈uvw〉 component in the unbending area (200 µm away from the cutting edge) and intermediate continuum-bent area. Additionally, the evolution of the texture from the {111} γ fiber to the {110} fiber was observed at the extremity of the cutting edge with the formation of shear bands.