For the past few years the customer's demand for more fuel efficient and at the same time safer vehicles has steadily increased. Consequently, light weight design has become one of the main interests in engineering. With regard to sheet metal components, a new class of high manganese steels, based on the TWIP (twinning induced plasticity) effect, provides the opportunity of shaping light weight designed thin and complex sheet metal geometries with advanced crash performance. In terms of weldability, due to their thermo-physical properties (high content of C, Mn, Al, Si), FeMn steels have to be handled differently in comparison to conventional steel grades. Particularly dissimilar material combinations of FeMn and ferrite steels are in the center of interest for industrial applications. This study reveals that metallurgical properties of dissimilar welding seams can be influenced considerably by laser beam welding, resulting in a change of the mechanical properties of the seam which is practicable without using filler material as described in (Flügge et al., 2011).

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Due to increasingly more stringent environmental and safety regulations as well as the globally increasing but locally different customer demands, automanufacturers are in search of measures to meet these requirements. In order to do so, research and development departments particularly focus on sustainable, light weight solutions. Based on material and load adapted design, an economic way of using new materials must be realized. This integral method of construction results in a diversified use of materials in automobiles. Consequently, dissimilar material combinations are increasing in number and importance, including crash-relevant structural parts. Concerning joining technology, light weight design is a challenge, because the ability to join dissimilar material combinations is often accompanied by small tolerance windows for the production process. In other words, minimum variation of process parameters may lead to a significant quality change of the properties of the seam. The present study deals with an experiment which aims at evaluating the influence of process parameters on the mechanical properties of overlap joints under impact loads. Its setup is based on the Charpy impact test and evaluated by means of laser beam welded overlap specimens of austenitic high manganese twinning induced plasticity steels and ferrite low carbon steels.