Effect of pulsing parameters on drop transfer dynamics and heat transfer behavior in pulsed gas metal arc welding

The effect of pulsing parameters on the metal and heat transfer behaviors in pulsed gas metal arc welding is investigated by a numerical model based on the solution of the magnetohydrodynamic equations within the framework of phase field method. Five sets of current waveforms using different peak current and duration (i.e. 300 A-2.30 ms, 350 A-1.80 ms, 400 A-1.45 ms, 450 A-1.20 ms and 500 A-1.00 ms) but maintaining an identical average current (i.e. 170 A) are considered and compared. The pulses using higher current but shorter duration result in more elongated shape of the pendent drop, earlier detachment, and significantly higher velocity of the detached drop. Unlike the drop velocity, higher peak current merely leads to a slight increase in the average temperature of the detached drop. The reason for this slight increase is that only the joule heating increases with the peak current, while the sheath heating and arc heating is governed by the average current and keeps almost constant using different pulsing parameters. The simulation results are compared with the high speed photos and exhibit good agreements.