Numerical Simulation Of Thermal Process In Laser+Pulsed GMAW Hybrid Welding Of Aluminum Alloy

Manufacturing of aluminum alloy structures by Laser+pulsed GMAW hybrid welding is of wide applications for greatly improving the welding efficiency and realizing weight reduction. Understanding of the process mechanism in hybrid welding of Al alloys is eagerly needed. It is of great significance to conduct numerical simulation of the thermal processes of hybrid welding, in order to provide the theoretical basis of process optimization and weld quality control.With considering the characteristics of high power Laser+pulsed GMAW hybrid welding of Al alloys, the effect of metal steam plume on the laser power absorption is dealt with, the previous model of keyhole profile is improved, and the calculation accuracy of keyhole profile in Laser welding is enhanced. The distribution parameters of volumetric heat source for laser beam is calibrated by using the calculated keyhole profile. In addition, the heat input from pulsed GMAW and overheated droplets are treated properly, and the combined volumetric heat source model for hybrid welding is established.Based on the volumetric heat source model for hybrid welding, the mathematical model of thermal processes in Laser+pulsed GMAW hybrid welding of Al alloys is developed. The weld formation and temperature field is numerically simulated. The data about weld formation and temperature field and thermal cycles are obtained for various welding conditions.For high strength6005A Al alloys, hybrid welding tests have been conducted. The transverse cross-section shape and size of the welds under various welding conditions are measured. The calculated results are in good agreement with experimentally measured ones, so that the mathematical model of hybrid welding aluminum alloys are validated.