Weld penetration depth, width, reinforcement and reinforcement to width ratio were defined as the factors to evaluate the weld shape. The effects of Nd:YAG laserzpulsed metal active gas (MAG) arc hybrid welding parameters on the weld shape were investigated with bead on plate tests. The results indicated that the laser energy mainly decides the weld penetration and the weld width depends on the arc for a given welding speed. The Nd:YAG laser has some effects on the hybrid weld appearance in varying of laser-arc distance and location of laser focus. The addition of laser energy in pulsed MAG arc welding can greatly increase its welding speed and the arc can improve the absorption of laser energy by workpiece. The test results also show that there is a matching relationship between the optimal laser-arc distance and the welding current for a given laser energy.

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Based on the bead on plate test and the effects of heat input on weld penetration, the equivalence between 2 kW CW (Continuous Wave) Nd:YAG laser power and pulsed GMA(Gas Metal Arc) power and the effect of welding speed on their equivalent ratios in welding carbon steel and Al alloy were studied. The studied results show that 9.8 kW pulsed GMA power is needed to reach the same weld penetration depth with 2 kW CW Nd:YAG laser power for welding of low carbon steel at v=1.2 m/min; for Al alloy, it is 3.92 kW pulsed GMA power. The equivalent ratios of 2 kW Nd:YAG laser power and pulsed GMA power are 4.9~6.4 and 1.85~2.1 times at different welding speed for low carbon steel and Al alloy, respectively. But their equivalent ratios have different variations with welding speed; at which the equivalent ratio of low carbon steel increases with welding speed and that of Al alloy decreases. The studied results offer the experimental boundary of heat input for analyzing the effect of Nd:YAG laser power and pulsed GMA power on laser+pulsed GMA hybrid welding process.