Induction assisted laser beam welding of high strength steel sheets

Abstract

Due to the high carbon levels of high-strength steels, laser beam welding of these materials generally leads to a substantial increase in hardness in the welding seam [1], which is often not acceptable. In order to achieve the required seam characteristics, process technical solutions are necessary, which allow adaptation of the welding seam characteristics to the basic material characteristics, and furthermore which can easily be integrated into the production chain.The use of a process-integrated heat treatment directly after laser beam welding has a high potential of meeting these requirements. By using serial short time tempering, the forming characteristics of tailored blanks made of high-strength steel grades can be improved. Furthermore, the ductility of laser welding seams on constructional elements can be optimized, in order to guarantee a sufficient energy absorptive capacity in case of a crash.The article gives an overview of different process-integrated heat treatment methods as well as their potentials and limits. The presented results refer to laser beam welding of butt and overlap welds for car body applications.Due to the high carbon levels of high-strength steels, laser beam welding of these materials generally leads to a substantial increase in hardness in the welding seam [1], which is often not acceptable. In order to achieve the required seam characteristics, process technical solutions are necessary, which allow adaptation of the welding seam characteristics to the basic material characteristics, and furthermore which can easily be integrated into the production chain.The use of a process-integrated heat treatment directly after laser beam welding has a high potential of meeting these requirements. By using serial short time tempering, the forming characteristics of tailored blanks made of high-strength steel grades can be improved. Furthermore, the ductility of laser welding seams on constructional elements can be optimized, in order to guarantee a sufficient energy absorptive capacity in case of a crash.The article gives an overview of different process-integrated heat treatment methods as well as their ...