Welding Techniques for Tailored Blanks

Welding principles and notes in laser welding, plasma welding and mash seam welding are discussed. Because of few amount of molten metal in laser welding, it is necessary to keep a gap narrow between welding edges and to track the weld line precisely. High tensile strength steel sheets are easy to weld, in plasma welding, with a lower current than mild steel. And, adding H 2 gas to a shielding gas is effective in improving plasma welding speed. It is necessary, however, to note that too much H 2 gas causes pores in welds. High-speed welding is possible in mash seam welding. Sheet's edges are lapped, then, force and electrical current are applied there with electrode wheels, in this method. Mash seam welding isn't suitable for sheets with too different thicknesses and tensile strengths. And also, cleaning of the electrode surface is necessary in welding of coated steel sheets.