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 in the 200 nm to 1000 nm wavelength range in TIG. The influence of welding parameters on the arc radiation was discussed. The radiation energy from the line emission mechanism was calculated and the comparison was made with the one from the continuum emission mechanism. The result shows that the radiation energy from the line emission mechanism 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 is presumed to be in a local thermal equilibrium (LTE) with light thinness property. The Bolzmann distribution and the Saha equation were applied to establish the arc light radiation model. This helps to lay the foundation for the further mathematical modeling of the arc light radiation.