One-sided laser beam welding of autogenous T-joints for 6013-T4 aluminium alloy

Abstract

Autogenous T-joints for aluminium skin-stringer component performed by one-sided laser beam welding process was conducted using a high power Yb-fiber laser. The influence of the shielding gas, seam angle, beam focal position, and beam positioning relative to weld centerline were investigated regarding to weld microstructural features. The joint mechanical behavior was evaluated concerning to the sheet rolling directions. It was observed that a precise control of the process parameters enabled to obtain weld beads with acceptable dimensional and geometric characteristics and minimizing weld defects. Helium shielding gas produced higher aspect ratio welds than those with pure argon. Although, pores were observed in the fusion zone, they represented only about 5% of the weld bead area. The optimal beam positioning should remain up to 0.2mm relative to junction line, for seam angles between 10° and 15°. The weld mechanical behavior depended on the sheet rolling direction. Joint efficiency up to 85% were obtained after hoop tensile tests when the weld bead longitudinal-section was perpendicular to skin rolling direction and parallel to the stringer rolling direction.