Aluminum Alloy Laser - Arc Hybrid Welding Temperature Field Of Numerical Simulation

Due to the advantages of light specific weight, high strength, good plasticity, superior corrosion resistance, no magnetism, easy workability, and no low temperature brittleness transformation etc, aluminum alloys are widely applied to variety of weldments fabrication. The laser-arc hybrid welding technique takes a full advantage of the two heat sources. It reduces or eliminates welding flaws to different degrees in different aspects, so that utilization ratio of the laser energy is improved. Thus it becomes one of the best choices for welding high strength aluminum alloys. The experiments of aluminum alloy hybrid welding indicate that under the same conditions the hybrid welding has characteristics of a bigger depth-breadth ratio, higher welding speed, greater energy utilization ratio and lower production cost. And production automation can be easily realized. The proper welding parameters for ZL114 alloy of 5mm-thick plane are: PYAG=3000W,UMIG=17.9V,IMIG=138A, with the welding speed 3m/min. The irradiated surface becomes molten and vaporized, and subsequently arises the crystallization of the weld metal. The interaction of the hybrid heat source with the target materials is a complex system of high speed, multi-dimension and multi-parameter, accompanied with different physical and chemical processes, such as heat and mass transfer, fluid fluxion, phases transformation. Above all, the energy absorption and transfer mechanism, keyhole and laser-induced plasma are the key factors which affect the deep penetration welding process and quality. Simulating the process is not only very complicated, but also challenging. The heat source coupling mechanism of laser-arc hybrid welding was investigated, hereby corresponding physical and mathematic models were established, and a computer program was made by using Newton iterative technique to obtain the weld temperature filed and the HAZ isotherms. Based on the ANSYS software, a double heat source model was adopted to deal with three-dimensional finite element dynamic simulation of hybrid weld. A finite element geometrical model was established corresponding to the hybrid welding temperature field, and simultaneously appropriate mesh was plotted. We can conveniently carry out the loading and unloading of the motional heat source by using the APDL language. Two kinds of models'computational results well coincide with the actual welds. Simulating the welding temperature field by using FEA(finite element analysis) and computer techniques, investigating the keyhole, laser-induced plasma in hybrid heat source welding, and studying heat source coupling mechanism can broaden the application field of laser processing and enhance our defense equipment.