Experimental and numerical studies on the influence of formability of AISI 316L tailor-welded blanks at different weld line orientations

The manufacturing industries are keen on understanding the effect of weld line orientation on the formability characteristics of tailor-welded blanks (TWBs) with sheets for the design and manufacture of structures with lightweight. The AISI 316L sheets of 2 mm and 1.6 mm were welded together by cold metal transfer (CMT) process using a welding current of 95 Amperes and a welding speed of 350 mm/min to fabricate TWBs. Two different TWBs were made with the welding line parallel to the rolling direction RD (WL||RD) and the weld line perpendicular to the RD (WL perpendicular to RD). The quality of the TWBs was evaluated by microstructural examination, mechanical integrity by tensile, hardness and Erichsen cupping test with laboratory-scale specimens. The engineering stress-strain plot and formability characteristics of the TWBs were considerably influenced by the weld line orientation with respect to the RD. It was noticed that the formability of TWBs decreased slightly compared to the base metal (BM) and fracture appeared in the thinner region (1.6 mm side), away from the weld line. Finite element (FE) prediction of Erichsen cup height was performed with ABAQUS software considering the weld metal properties. FE analysis using Johnson-Cook damage criterion predicted a cupping height that showed good coherence with experimental measurements for BM and TWBs with an error percentage less than 5. The stress distribution was non-uniform in the deformed TWBs with more stretching, and the magnitude of deformation was higher in the thinner region.

Automated summary

The research found that the orientation of the weld line relative to the rolling direction has a significant impact on the engineering stress-strain curve and formability characteristics of tailor-welded blanks (TWBs). Compared to the base material, the formability of TWBs slightly decreases, with fractures appearing in the thinner regions.