A theoretical model of arc light radiation based on GTA spectral diagnosis

An arc light radiation phenomenon in TIG welding process was studied through experiments and theoretical analysis. The arc spectra were acquired under a variety of welding parameters from 200 nm to 1000 nm wavelength range in TIG. The influence of welding parameters on the arc radiation was discussed. The radiation energy from lines emission mechanisms was calculated and the comparison was made with the one from the continuum emission mechanisms. The result shows that the radiation energy from the line emission mechanisms is equal to the one from the background. Based on the experiments and analysis, a physical model of arc light radiation has been developed. In this model, the arc plasma was presumed to be in local thermal equilibrium (LTE) with light thinness property. The Bolzmann distribution and Saha equation were applied to establish the arc light radiation model. This helps lay the foundation for further mathematical modeling of the arc light radiation.