Partial Thinning Method for Steel Sheets by Bending-Assisted Compression Drawing

Abstract

Tailored blanks with in-plane differential thickness are required to reduce automobile body weight and satisfy two or more strength requirements in one panel. We developed a method of partial thinning in the width direction of steel sheets by bending-assisted compression drawing. This method reduces shear deformation energy by combining bending deformation and compression deformation, which can lead to a reduction in forming load. In this study, we conducted an experiment to partially reduce the thickness about 10 mm from the width edge of the mild steel sheet by the proposed method. We found that this method enables us to partially reduce the mild steel sheet thickness by 30% on the blank edge side. Furthermore, we combined the proposed method with a continuous stretch-bending method that can partially reduce the thickness in the longitudinal direction (drawing direction). As a result, a tailored blank with in-plane differential thickness was demonstrated experimentally.