Double-Sided GTA Welding of Aluminum Alloys with Single Power Supply

Joint preparation and multiple passes are among the most important factors dominating the cost and productivity of welding. If a required penetration is achieved in a single pass with square butt joint, the resultant cost reduction and productivity improvement will be significant. To improve penetration, two gas tungsten arc welding torches are placed on the opposite sides of a workpiece and are connected in series to a single power supply. The current directly flows through the workpiece and arcs are concentrated. As a result, penetration capability is significantly improved. LASER BEAM AND electron beam welding can produce much deeper penetration than arc welding. However, compared with the most widely used metal joining method, arc welding, laser beam and electron beam welding achieve deep penetration at the expense of high cost. Approaches have been applied to increase weld penetration during arc welding. One approach is to use flux to change the fluid flow in the weld pool during gas tungsten arc (GTA) welding. Significant improvement in penetration has been observed [1]. Another method involves the use of two independent sets of torch and power supply for simultaneously welding the work from the opposite two sides. Two conventional power supply-torch-work-power supply loops parallelly function and approximately twice penetration is achieved. Although it does not change the mechanism of conventional arc welding where the power supply-torch-work-power supply loop is essential, this approach has found successful applications when the both sides of the work are accessible.