NUMERICAL SIMULATION OF WELD FORMATION IN LASER plus GMAW HYBRID WELDING III. Treatment of Pulsed Arc Action and Improvement of Heat Source Modes

Considering the thermal action characteristics of pulsed are in laser+pulsed GMAW (gas metal are welding) hybrid welding, the arc heat flux is divided into two double-elliptic distribution modes with different parameters corresponding to pulse current duration and base current duration. Meanwhile, the thermal conductivity at the weldment surface is appropriately lowered to take account of intermittent action of pulse and base current indirectly. Based on the level of averaged welding current, the distributed region for double-ellipsoid of droplets heat content is determined, and the action location of laser heat input is taken into consideration. The previous heat source modes have been improved through dealing with the abovementioned aspects, and two new kinds of adaptive combined volumetric heat source modes are developed. The weld geometry and dimensions are numerically simulated under different conditions in hybrid welding process by using the improved heat source modes. The predicted weld penetration depth, width and fusion line locus all agree well with the experimental results. Thus, numerical simulation accuracy for hybrid welding has been greatly improved.