Influence of the Welding Angle on the Mechanical Behavior of Plates obtained by the Tailor Welded Blank (TWB) Process

Abstract

Tailor Welded Blank (TWB) is a top-welding technique (by unconventional processes) of sheets of different specifications (materials, thicknesses and/or coatings). Because it allows localised distribution of mechanical properties and mass, it can optimise the relationship between structural rigidity and total weight. The great challenge of this technique is to combine two processes with completely different demands, welding and mechanical forming. This work investigates the mechanical behavior of sheets obtained by the Tailor-blank process from the determination of the optimum angle. We performed tensile tests on sheets with different weld line inclinations, as the general objective is to consolidate knowledge about the process, characterise the conditions for sheet formation obtained by the technique, in a safe conformation range, with complex contours, dimensional qualities and free of catastrophic failure. Steel sheets, interstitial free (IF), of 1.10mm and 0.65mm thick were used. The TWB was applied with a welding line oriented from 0º to 90º (ranging from 15° to 15°). The optimum angle obtained was 30º, where there was a good relationship between the breaking load, purely tensile and shear stresses, and the total elongation. In relation to the angle of 0º, the optimum angle presented a superior elongation of approximately 40%. It was still possible to notice that the thickness of the plates influenced the optimum angle, even if the LSR (Limit Strength Ratio) is close.