Detection of GTA welding quality and disturbance factors with spectral signal of arc light

By just artificially causing disturbance factors, the change in the spectrum of the welding arc is studied in order to identify special spectral processing zones that could provide signals, with high signal to noise ratio, for a proper evaluation of the GTAW (gas tungsten arc welding) process. Furthermore, the selected spectral processing zones were applied for in situ detection of the welding trails with the disturbance factors. The results have shown that by using suitable spectral processing zones (250-300 nm, 750-830 nm, 776.6-777.6 nm, 867.5-868.5 nm, 900-1000 nm), welding defects, such as bead face discontinuity, poor weld and porosity, which are usually caused by different disturbance factors, could be detected and identified. The present study is an attempt to put on theoretical basis the in situ detection and control of GTAW process.