Study on laser keyhole behavior in high-efficiency low power pulsed laser-TIG hybrid welding process

Abstract

Laser-tungsten inert gas (TIG) hybrid welding has been attracted much attention due to its advantages such as deep penetration, high efficiency and good quality. Laser-TIG hybrid welding processes with different parameters are proposed and the Mg plasma behavior is observed. While butt joints are made by laser welding, TIG welding, and laser-TIG hybrid welding, the welding efficiency in each process is compared and the reasons are discussed. Results indicate that the formation of laser keyhole and keyhole plasma is the premise of efficient hybrid welding. The parameters, including laser peak power, distance between laser and arc, arc current, greatly affect the Mg plasma behavior in hybrid welding. Optimized parameters can keep the keyhole open and stable. This process enhances the stability and the energy density of arc and extends the delay time of Mg plasma. So the welding efficiency can be greatly increased. The welding efficiency of hybrid welding is 7.14 times of laser welding and 4.29 times of TIG welding.