Development of trimming die with 1.2 GPa steel grade

AbstractIn order to reduce the weight and to improve the crash performance of the vehicle, advanced high-strength steel of DP980 and CP1180 has been widely used in the automotive industry. However, the high-strength steel in the press parts causes severe tool wear or failures, such as adhesion, chipping and fracture at the tool cutting area during the shearing process. These result in the excess burr which deteriorates the tool life and causes serious problem in the product quality. The objective of this study was to evaluate the effect of the characteristic of sheared surface on the die material and surface treatment conditions at the shearing process with 1.2 GPa steel grade. The characteristics of sheared surface were evaluated after the shearing process of 60,000 strokes. A burr height was measured using the illuminometer. Also, tool wear of failures was analysed through observing microstructure. The shearing conditions such as die material, heat treatment and process parameter of clearance and pad fo...