Product Code: ICAL06_1701

Induction Assisted Laser Welding of Advanced High Strength Steels to Increase the Formability of Welded Automotive Body Structures
Authors:
Axel Jahn, Fraunhofer IWS; Dresden Germany
Berndt Brenner, Fraunhofer IWS; Dresden Germany
Eckhard Beyer, Fraunhofer IWS; Dresden Germany
Presented at ICALEO 2006

Advanced high strength multi phase steels are currently approaching to practical application in the automotive body industry. The outstanding mechanical properties of these materials, e.g. high strength and excellent formability, base on the multi phase structure. Due to high productivity and narrow heat affected zone, laser welding is a profitable production procedure for joining these materials in semi-finished production and in body in white manufacturing. But the enhanced content of alloying elements causes an increased hardening 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 mechanical properties of the welded joint several strategies of induction assisted laser welding have been investigated. The optimized welding procedure realizes a hardness reduction and a significant increase of ductility. This makes the adjustment of the weld seam formability possible and improves the joint properties adapted to the functional requirements. The formability of laser-induction welded structures of various materials have been discovered by determination of forming limit curves. The results enable the assessment of the forming behaviour of complex welded components as well as the estimation of the material performance in case of crash.