Stamping is mainly classified according to process and can be divided into two categories: separation process and forming process. The separation process is also called blanking. Its purpose is to separate the stamping parts from the sheet along a certain contour line while ensuring the quality requirements of the separated section. The surface and internal properties of stamping sheets have a great influence on the quality of stamped products. The thickness of stamping materials is required to be accurate and uniform; the surface is smooth, no spots, scars, scratches, no surface cracks, etc.; the yield strength is uniform and has no obvious Directionality; high uniform elongation; low yield-to-strength ratio; low work hardening.