A Study on Effects of the Press Speed on Sheared Edge Formability

Abstract

In this study, the effect of shearing speed on edge formability was investigated with two different grades of advanced high strength steel (AHSS), DP780 and GEN3-980. A straight blanking tool with adjustable shear clearance was used to shear the selected materials in two different type presses, a high-speed pneumatic press, and a mechanical servo-press. The four different shearing speeds from 0.01 meter per second up to 1.5 meters per second were realized and measured. The different shearing speed conditions result in different edge quality and work hardening levels. The half specimen dome test and micro-hardness analysis were conducted to evaluate the edge formability. The samples sheared with a pneumatic press at a higher speed showed significantly better edge quality, less hardness increase, and smoother sheared edge than the samples sheared with the servo press. The developed high-speed shearing condition has a very good potential to shear AHSS without creating significant damage and work hardening on the sheared edge, providing further advantages for the post stamping operations.