Influence of the laser radiation on the plasma dynamics during arc-laser welding

The temperature distribution of the plasma plume occuring during TIG-arc- and Nd:YAGlaser- arc (hybrid) welding of steel (St 52) and aluminum alloy (AlMg3) is measured using emission spectroscopy. For steel the temperature distribution differs for arc- and the hybrid welding. For the aluminum alloy only laser-arc welding gives a stable plasma plume, which is similar to the temperature distribution of the plume occuring during arc welding of steel. A model is established to simulate the dynamics of the plume incorporating the anode fall region and the evaporation from the laser-induced keyhole. It is used to calculate the temperature, the current density and the velocity field of the plume for the processing of iron and aluminum.