The reason of cracking is that the cold work hardening index of austenitic stainless steel is high. The austenitic stainless steel is metastable, and transformation occurs during deformation, which induces martensite phase. Martensite is brittle, so it is easy to crack. The relationship between residual stress and martensite content: the higher the induced martensite content is, the greater the residual stress is, and the easier it is to crack in the process of processing.
2. Causes of surface scratch: the scratch on the surface of stainless steel drawing part is mainly due to the relative movement between the workpiece and the die surface. Under the action of a certain pressure, the blank and the local surface of the die directly produce friction. In addition, the deformation heat of the blank makes the blank and metal chips deposit on the surface of the die, resulting in scratches on the surface of the workpiece.