NONAXISYMMETRIC CONVECTION IN STATIONARY GAS TUNGSTEN ARC WELD POOLS

Observations of surface flow patterns of steel and aluminum GTAW pools have been made using a pulsed laser visualization system. The weld po ol convection is found to be three-dimensional with the azimuthal circ ulation depending on the location of the clamp with respect to the tor ch. Oscillation of steel pools and undulating motion in aluminum weld pools are also observed even with steady process parameters. Current a xisymmetric numerical models are unable to explain such phenomena. A t hree-dimensional computational study is carried out in this study to e xplain the rotational flow in aluminum weld pools.