Weldment properties evaluation and formability study of tailor-welded blanks of different thickness combinations and welding orientations

Tailor-welded Blanks (TWBs) are tailor-made for different complex component designs by welding multiple metal sheets with different thicknesses, shapes or strengths prior to forming. However, the forming performance of an intrinsic TWB is critically related to its own structures and designs, such as the thickness combination, as well as the location and orientation of weldment. In this study, a 2 kW Nd:YAG laser were used to butt-weld approximately 180 samples of stainless steel (AISI 304) TWBs with different dimensions (i.e., from 12.7 mm to 165.1 mm in width), thickness combinations (i.e., 1.0/1.0 mm, 1.0/1.2 mm, 1.0/1.5 mm, 1.2/1.2 mm, 1.2/1.5 mm and 1.5/1.5 mm) and welding orientations (i.e., 0°, 45° and 90°). Subsequently, Swift forming tests were carried out to characterize the forming performance of those TWBs. Obviously, the optimal sets of welding parameters relating critically to the quality of weld was a primary criterion for the formability test of TWBs in this study. The effects of different thickness combinations on the formability of TWBs were investigated through the constructed forming limit diagrams (FLDs). The results showed that the thinner part of TWBs dominated the majority of deformation similar to the FLD of the parent metal. The effects of different welding orientations on the forming performance of TWBs were examined from the failure analysis.