Abstract
In order to obtain guidelines for the choice of appropriate welding processes for the tailored blanks using advanced high strength steel sheets, the formability of welded steel sheets were investigated. The purposes of this work are 1) to determine an upper steel strength limit that can be welded and 2) to investigate the deformation behavior of welded high strength steel sheets. Laser, mash seam, and plasma arc welding were employed up to 1180MPa high strength steel sheets. The results suggested that laser welding was the best welding process because of its small heat input and narrow weld width. It could be applied to 980MPa or 1180MPa steel sheets. On the other hands, 590MPa was the maximum strength grade to which mash seam and plasma arc welding could be applied. The reason is that the mash seam and the plasma arc welding thermal cycles softened the HAZ of high strength steel.
