Prevention of Local Thinning and Springback in Hot Stamping of Thin Sheets

Abstract

In hot stamping of thin quenchable steel sheet, local thinning, springback and hardness of stamped parts were investigated. The sheets having 0.6, 1.0 and 1.6 mm in thickness were heated at 900 °C by a furnace and hot-stamped into a hat shape. Local thinning around the bottom corner of the hat-shaped part for a thickness of 0.6 mm was considerably remarkable in comparison with those above 1.0 mm in thickness. Local thinning was relieved for a transfer time of 15 s from the furnace because of the uniformity of the temperature distribution. In addition, the springback was prevented above 5s.