Research on aluminum alloy welding process based on high frequency and low power pulsed Laser-MIG hybrid welding

Abstract

Taking 2219 aluminum alloy as the welding research base metal, a high frequency and low power pulsed laser-MIG hybrid welding system was established. When the laser pulse frequency ranges from 500 Hz to 1500 Hz and the laser-wire distance ranges from 1 to 2 mm, the effects of high-frequency and low-power pulsed laser on the arc shape, metal transfer behavior, and weld formation in the hybrid welding process were compared and analyzed by using high-speed camera system and electrical signal acquisition system. The results show that as the pulse frequency increases, the arc is gradually compressed, and the compression reaches the maximum when the frequency is 1500 Hz. In the test, the limit distance of laser attracted arc is 2 mm and the limit distance of laser stabilized arc is 1.5 mm. From the collected electrical signal, it can be seen that the welding current is reduced by 5.8A after adding laser irradiation. Since the welding power source is a constant voltage source, the welding voltage is almost constant, so the heat input of the welding arc to the base metal and droplets is reduced to a certain extent. When the laser is biased laterally along the welding wire, the weld morphology also shifts from the center to the laser irradiation point, which further verifies the guiding effect of the laser on the arc. In addition, the addition of the laser effectively improves the stability of the welding process, the weld seam is formed uniformly, and the oscillation of the molten pool caused by the laser accelerates the discharge of gas in the molten metal, which effectively reduces the pore defects.