On-line monitoring and defect detection of arc-welding via plasma optical spectroscopy and LIBS

Plasma optical spectroscopy and laser-induced breakdown spectroscopy (both on and off-line) are used in this work to analyze the effects of different perturbations applied to a tungsten inert gas welding process. This approach enables the analysis and comparison of the spectra acquired with the two setups, thus providing more information about the process evolution and dynamics and the resulting chemical composition of the seams. It will be demonstrated that, in agreement with previous studies, the analysis of different elements gives rise to rich information regarding the resulting weld quality, thus enabling the on-line monitoring of arc-welding processes. Elements such as lithium or sodium, not commonly employed in spectroscopic analysis of welding processes, will prove to provide interesting information on surface defects and contamination. Additionally, LIBS 2D scanning of the performed seams will enable a detailed analysis of the resulting elemental distributions.