Determination of forming limit curves in laser-or electron-beam-welded tailored blanks

In the last few years various groups of high-strength cold-rolled steels have been developed for the car body lightweight design. Apart from this materials development, new concepts of lightweight construction have been worked out, as, e. g., welded blanks (so-called tailored blanks). These sheets, consisting, of different materials and/or of different sheet thicknesses, are being evaluated in this paper regarding their formability. To this end, forming limit curves are determined by experiment and calculated by means of a finite element model. It turns out that the failure behaviour is influenced by the shape and structure as well as the position of the weld during the forming test. In this process, the width of the weld is more significant than the local hardness increase.