Induction assisted laser welding of advanced high strength steels to increase the formability of welded automotive body structures

Advanced high-strength multi phase steels are currently approaching to practical application in the automotive body industry. The outstanding mech. properties of these materials, e.g. high strength and excellent formability, base on their multi phase structure. Due to high productivity and low heat input, laser welding is a profitable prodn. procedure for joining these materials in semi-finished prodn. and in body in white manufg. But the enhanced content of alloying elements of high strength multi phase steels causes an increased seam hardness which results in a reduced ductility within the weld metal and the HAZ and leads to a severely restricted formability of the welded structure. In order to improve the mech. properties of the welded joint several strategies of induction assisted laser welding have been investigated. The optimized welding procedure realizes a hardness redn. and a significant increase of ductility. This makes the adjustment of the weld seam formability po