“…Spectroscopy of welding arc contains abundant information of weld metal components, welding current, arc voltage and shielding gas components and presents a close correlation to the welding process, therefore, can be used to monitor the welding quality effectively [7][8][9]. Schellhorn [10] monitored the spectroscopy of laser-induced welding plasma and revealed the reason why the weld seam quality of AlMgSil (6082) alloy obtained with the CO laser was better than that with CO 2 laser.…”