Correlation between laser-wire distance and Nd：YAG laser ＋ P-GMA hybrid welding heat input parameters

In laser ＋ P-GMA hybrid welding, laser-wire distance is an important parameter to describe the distance from laser spot to the center of the pulsed gas metal arc. The experiments results show that the optimal laser-wire distance with the deepest weld penetration increases with welding current and laser power being increased and decreases with welding speed being increased. Welding current, laser power and welding speed determine the hybrid welding heat input in laser ＋ arc hybrid welding process, so there is a correlation between the optimal laser-wire distanee and the hybrid heat input welding parameters for the deepest weld penetration： the optimal laser-wire distance increases with the heat input being increased. The positive correlation between the optimal laser-wire distance and the hybrid welding heat input is induced by the characteristics of the limited influence of P-GMA welding process on laser transmission and the dependence of weld penetration of hybrid welding on laser power.