Study of metal transfer in CO2 laser+GMAW-P hybrid welding using argon–helium mixtures

•The laser destroyed the force balance and thermal equilibrium of GMAW-P.•The shadow graph technique and optical emission spectroscopy was employed.•The laser exerts a attaching force that sustains the droplet.•We reported a metal transfer optimization method.

The metal transfer in CO2 Laser+GMAW-P hybrid welding by using argon–helium mixtures was investigated and the effect of the laser on the mental transfer is discussed. A 650 nm laser, in conjunction with the shadow graph technique, is used to observe the metal transfer process. In order to analyze the heat input to the droplet and the droplet internal current line distribution. An optical emission spectroscopy system was employed to estimate default parameter and optimized plasma temperature, electron number densities distribution. The results indicate that the CO2 plasma plume have a significant impact to the electrode melting, droplet formation, detachment, impingement onto the workpiece and weld morphology. Since the current distribution direction flow changes to the keyhole, to obtain a metal transfer mode of one droplet per pulse, the welding parameters should be adjusted to a higher pulse time (TP) and a lower voltage.