Influence of Arc Pressure on Weld Pool Geometry

At currents over 300 amperes, the surface of the weld pool becomes markedly depressed and the assumption of a flat surface is no longer valid. In order to predict the weld pool geometry, the shape of the surface depression under the action of the arc pressure has been calculated. At currents of 300 amperes, it is found that the arc pressure cannot account for either the depth or the shape of the experimentally observed surface depression. Instead, a new model of a compound vortex is proposed as a possible mechanism to explain the deep surface depression in this current range.