A spectroscopic study of the GTAW plasma-plume created during the welding of stainless steel and
other materials (iron, nickel and chromium) has been carried out. The spectra of these plasmas have been studied
for several welding parameters. Temperature calculations are based on the observation of relative intensities and
shapes of the emission peaks. We assume that the plasma is in local thermal equilibrium. The temperature is
calculated with the Boltzmann plot
method from twelve iron emission lines
(in the range 368–385 nm): it
varies between 9650 and 12100 K. Dilution experiments have been carried out. We checked the mixing of
metals: during welding of two different metallic plates and during welding with an Inconel wire. Dilution is
monitored following the intensity of some characteristic emission lines (chromium and nickel). Comparison of
spectroscopic results and metallographic ones is made.