Springback characteristics of the tailor-welded strips in U-bending

In this study, the springback characteristics of tailor-welded strips in U-bending processing were investigated. The tailor-welded strips were joined by the laser welding process and consisted of two types of thickness combinations of the SCP1 sheet, 0.8t×1.2t and 0.8t×1.6t, to investigate the effect of different thickness combination on the springback. And two different welded strips, one was welded along the centerline of the strip-width and the other was welded along the centerline of strip-length, were adopted to compare the effects of weld-line locations on the springback. Three punch profile radii of 3, 9 and 15 mm were used. Some selected cases from the experiments were simulated using a commercial finite element program, PAM-STAMP. In cases of the longitudinally welded strips, the springback was generated as much as the one generated in the non-welded strips, which are the same thickness as the thicker side of the longitudinally welded strips. And, in the cases of the centrally welded strips, a significant reduction of the springback was observed in the thinner side compared with the same thickness of non-welded strip. On the other hand, the springback of the thicker side was similar to the one of the same thickness non-welded strips.