Characteristics and experimental analysis on force and heat transfer in laser pulse-assisted metal transfer process

Abstract

In the laser pulse-assisted metal transfer process, the recoil force generated at the laser incident point replaced the electromagnetic force. A stable one droplet per pulse (ODPP) short-circuiting or spray transfer process obtained at a relatively low current. The morphology of the solid-liquid interface changes after the laser incident, and there is a relatively complicated force-heat interaction phenomenon/process. Firstly, the evaporation mass of the droplet surface after laser irradiation was measured, and the evaporation power consumption of the laser to the droplet was calculated. According to the melting increment of the welding wire, the melting power consumption of the pulse laser on the welding wire was calculated. The dynamic change process of metal plume was observed by a high-speed camera. According to the experimental calculation, the initial velocity of droplet falling off the welding wire was measured, and the horizontal and vertical impact force of the pulsed laser on the droplet was obtained. The total evaporation recoil force was 7.81 × 10−2 N. Secondly, the temperature changes of characteristic points around the molten pool under different laser process parameters were measured. With the increase of laser pulse frequency/laser power, although the heat input of the base metal gradually increased, the measured temperature rise of the characteristic points was less than the temperature of the laser-arc hybrid process. The deposition rate of dual-pulse laser-assisted GMA welding at 75 Hz is about 1.4 times that of traditional MIG welding.