SPECTROSCOPIC DIAGNOSTIC OF ARC AND WELDPOOL IN GAS METAL SHORT ARC WELDING PROCESSES

The reduction of the power consumption and the heat input into the workpiece has been aimed in the development of controlled short arc welding processes. The choice of the shielding gas is an important process parameter to adjust the joining quality. The use of either the rare gas argon with small additions of molecular gases or the pure active gas CO2 results in different arc structure and weld pool behaviour. Optical emission spectroscopy and high-velocity imaging are applied to determine plasma temperatures and metal vapour densities in the arc as well as surface temperatures of the weld pool. The behaviour of the arc core is dominated by metal vapour and depends strongly on the shielding gas.