Arc Behavior Study Using Welding Current Module and its Impact on Residual Stress and Weld Bead in Anti-Phase Synchronized Twin-Wire Gas Metal Arc Welding

Abstract

The importance of twin-wire welding in increasing the deposition rate is known for a long, but its application in gas metal arc welding is limited due to the arc-stability related issues. An unstable welding arc causes irregular weld bead and material loss in the form of spatters. Previous investigations indicate that the problem can be addressed through arc-stability induced by dissimilar twin-arcs as the electromagnetic field concentrates around the arc with higher current. The present study is intended to reduce the twin-arcs' interactions and to improve the arc stability in twin-wire gas metal arc welding by evaluating different conditions at lead and trail wires. Further, their influence on the residual stresses and weld bead geometry is studied. Bead-on-plate-welds are carried out. A data acquisition system is used to capture the electrical signals during welding. The results indicate that the unequal currents at trail and lead wires provide stability to the arc that also results in a shift in residual stresses from compressive to tensile along the weld transverse direction. In addition, the maximum residual stress is located at the weld toe. When the current difference between the trail and lead wire is more, the arc produces stable metal transfer with uniform heating and cooling that results in reduction in stresses and improvement in weld quality.