Abstract
2 kW Fiber laser and 2.4 kW CO2 laser were used to investigate their welding characteristics of laser and laser-MAG hybrid welding processes. The effect of defocusing distance and welding speed on the weld bead and plasma interaction were investigated. Fiber laser can achieve deeper penetration weld bead than CO2 laser at the same welding speed and output power in laser welding. It is well known that the plasma produced by laser affects penetration and bead width in laser-MAG hybrid welding. The plasma produced during fiber laser-MAG hybrid welding is weak. On the contrary, the plasma produced during CO2 laser-MAG hybrid welding is very strong. The volume of plasma produced during hybrid is affected by laser-arc distance in laser-MAG hybrid welding. High energy density short wavelength fiber laser can couple with the arc completely than using long wavelength CO2 laser in laser-arc hybrid welding when the MAG power changed.
