Abstract: Through collecting MIG welding arc light spectrum of steel, the basic characteristic of the spectrum distribution is studied. Based on the analysis, special spectral zones are selected for collecting the light spectral signal of welding process with preset disturbance factors. The studies aim to acquire the theory base of online welding quality test and control based on arc light spectrum and its application. The results show that there are aggregation zones of metal spectral line and Ar spectral line in different spectral zones. The different transfer mode of welding droplet in different arc length have characteristic signal in the special spectral zone. The bead broadening caused by welding current variation also has good characteristic signal. The welding defect caused by different disturbance factors has its signal characteristic in different spectral zone. Through collecting the light spectral signal of welding arc in the special zone, information related to the welding quality can be acquired to realize classification and identification of MIG welding quality.

Key words: Arc light spectrum, Disturbance factor, MIG welding, Welding quality