Hybrid Laser-Arc Welding of AA6061-T6 Butt Joints

Abstract

Hybrid laser-arc welding (HLAW) of butt joints in 3.18 mm thick aluminum alloy (AA) 6061-T6 sheets was investigated in the present study. Under optimized process conditions, high integrity welds with approximately 2% shrinkage and gas porosity were obtained. The weld bead geometry was determined to conform to the crown and root reinforcement specifications for welded aluminum construction - CSA W 59.2 M1191. Softening in the heat-affected zone (HAZ) and fusion zone (FZ) of the welds was observed, the former due to grain coarsening and the latter due to the dissolution of the hardening precipitates as well as the dilution from the application of the ER 5356 filler wire. Under optimized process conditions, the gap tolerance was determined to be 0.5 mm, beyond which the performance of the joints during bend testing was compromised.