Punch Edge Topological Design for Reduction of Work Hardening Damage in Shearing of Non-Oriented Electrical Steel Sheets

A new shearing tool was demanded to reduce the iron loss of motor cores by minimization of work hardening damages into the sheared non-oriented electrical steel sheets. The punch edge topology as well as the clearance between the punch and die were controlled to investigate their influence on the sheared surface condition and the work hardening damages of steel sheets. In particular, the hardness mapping was utilized to quantitatively analyze the work-hardened area in the sheared steel sheets and the dissipation plastic work. Among four punch edge topological configurations, the nano-grooved punch in straight along the shearing direction induced the minimum damage into the sheared steel sheets.