RELATIVE INFLUENCE OF SHEET ROLLING DIRECTION AND WELD ORIENTATION ONFORMABILITY OF LASER WELDED STEEL SHEET

The introduction of tailored welded blanks offers many potential benef its to both the steel production and automotive industries. However, t here are difficulties associated with the pressing of such blanks, ste mming from the industry's lack of experience concerning the forming ch aracteristics of the weld and its effect on the surrounding material. This research programme has focused on laser welded steel samples of t hicknesses typically used in the automotive industry. A modified Erich sen cupping test was used to deform the laser welded samples to fractu re, and subsequent analysis of the surface strains around the weld and the fracture site was used to compare the formability of the samples. An assessment was also made of the effect of experimental accuracy in the cupping tests on the observed strain conditions. The most promine nt influence on formability was found to be the sheet rolling directio n and not, as expected, the presence of the laser weld or the weld rou te through the sample. Furthermore, an unpredicted result was obtained when the orientation of the laser weld was changed relative to the mo vement of the punch.