Weld orientation effects on the formability of tailor welded thin steel sheets

Tailored welded blanks (TWBs) technology can give the important possibilities to obtain components in the automobile industry. Friction stir welding (FSW) is a joining approach, which can adhere parts well with desired properties in weld zone. In this article, the main aim is investigation the effect of weld zone orientation on forming limit diagram (FLD) of the TWBs using experimental and finite element model. Three TWBs are produced FSW with three different orientations of weld zones including 0(0), 45(0) and 90(0) against major stress direction. The microstructure of the weld zones is divided and then observed via metallography procedures. Tensile tests are carried out to determine the mechanical properties of TWB sections and duplicate the tests numerically to validate the formability results. The Nakazima stretch test is used to derive the limit strains for three different weld orientations (between rolling direction and welding path) and what can be seen is the changeable effect of these ordinations on varying strain paths. The best formability is for TWB with orientation weld 90(0) in tension mode while, results reveals that in Plane strain condition best formability is originated from TWB with weld orientation 0(0). For biaxial tension condition epsilon(2) = epsilon(1), changing the weld orientation has no effect on formability. The comparison between FEM and experimental tests reveals good agreement and high recommended FEM for this type of study.