Optimum clearance determination in blanking coarse-grained non-oriented electrical steel sheets: experiment and simulation

Blanking process plays a critical role in the deterioration of magnetic properties of coarse-grained non-oriented electrical steel of motors. With the decrease of grain number in the thickness direction, the deformation behavior in blanking process becomes different and complex. In this paper, the high-grade non-oriented electrical steel is selected for blanking tests within the relative blanking clearance range. The results show that there exists an optimum clearance which leads to the high-quality sheared edge for the application. Nevertheless, the exact value of optimum clearance cannot be provided by experiments. Therefore, a novel Voronoi-based FE model is established to analyze the blanking deformation behaviors of individual grains. The flow stresses of surface and internal grains are identified through the widely applied surface layer theory. The proposed FE model is an appropriate prediction tool for simulating the blanking process of non-oriented electrical steel sheets. Meanwhile, through the new proposed model, an exact optimum clearance determination method is established. The proposed methodology predicts that the optimum clearance for the investigated sheet is 13.8%t, which is further verified by the experimental data.