DETERMINATION OF GAS TUNGSTEN ARC-WELDING EFFICIENCIES

A combined experimental/computational technique for the estimation of gas tungsten arc welding (GTAW) efficiencies under quasi-steady condit ions is presented. The instantaneous measurements of the weld pool len gth ahead of and behind the electrode are obtained from digitized free surface images, using a pulsed laser vision system. Measurements of t he width and depth of the pool are obtained from weld sections using o ptical microscopy. Based on these measurements of the actual fusion bo undary created by weldpool convection and other effects, a three-dimen sional model outside the molten zone in the solid material is used to determine welding efficiency. Measurements and calculations are perfor med for a range of power inputs and torch speeds for both grooved and ungrooved, high-yield strength steel samples. Computed efficiencies ar e compared with those available in the literature.