Spring Back Behavior in Hat-Shaped Draw Bending Test of Laser-Welded Tailored Blank

Abstract

To reduce the weight of and to increase impact safety in a car body, the spring-back behavior of laser-welded tailored blanks (TBs) in draw bending has been examined both experimentally and numerically. The materials used in laser-welded TB are a mild steel sheet (270MPa strength) and high-strength steel sheet (440MPa strength). The thicknesses of the sheets are 0.8 mm (thick) and 1.2 mm (thick). Results have indicated that spring-back of all TB combinations (the same thickness and different strength, different thickness and the same strength, different thickness and different strength) were nearly equal to the spring-back of a single thick sheet or low strength sheet. Elastic restoration of one part of TBs was controlled by the other part of TBs.