Metal vapors in gas tungsten arcs: part i. spectroscopy and monochromatic photography

Metal vapors in gas tungsten welding arcs were studied in order to determine the effects of these vapors on arc properties and subsequently on weld bead configuration. Emission spectroscopy and monochromatic photography were used to determine the prominent metal species present and their distribution in arcs on stainless steel. It was found that, in addition to the expected species (Fe, Mn, Cr), calcium and aluminum vapors were also detectable, although these elements were present in the base plate only at very low concentrations. All metal vapors were determined to be concentrated just above the weld pool in high current arcs, but were also detected in the upper regions of low current arcs. Aluminum, calcium, and sometimes thorium were found to vaporize from the tungsten electrode.