Analysis of droplet behavior in Nd:YAG laser-pulsed MAG hybrid welding

This paper studies the metal transfer phenomenon of Nd:YAG laser-pulsed MAG hybrid welding. High-speed video camera has been used to record droplet formation, growth and shedding process, observation and analysis for the effect of laser on the droplet transfer of arc welding can be conducted. The results show that the laser changes the droplet flight path, the transition stability and metal transfer mode. A mechanical model established to analysis how laser join influence the force on the droplet in pulsed MAG welding. Analysis showed that when hybrid with laser, the pulse MAG droplet is also subject to additional role of two forces, one is an anti-thrust force produced by the high-speed metal vapor eruption from keyhole acted on the droplet, the other is an anti-thrust force produced by the radiation of laser and laser-induced plasma let the surface of the droplet high-speed evaporation and reverse thrust. When the distance between laser and arc less than 2 mm, these two forces will hinder the droplet, and the electromagnetic force bias direction to laser keyhole. The metal transfer stability Nd:YAG laser-pulsed MAG hybrid welding affected by such as light DLA, laser power and defocus.