A Study On Laser-Arc Hybrid Welding For Aluminum Alloy And Numerical Simulation For The Temperature Field

Aluminium alloys are widely applied as weldments in industry for their light specific weight, high strength, good ductility, superior corrosion resistance, non-magnetism, easy workability, and no low temperature embrittleness transition etc, but their welding always is a problem. The laser-arc hybrid welding is a novel technique which has a synergic effect of"1+1ï¹¥2". It doesn't only improve the efficiency of the laser, but also reduces or eliminates welding defects.YAG-MIG hybrid welding system for Aluminum alloy was built for the first time in China. Paramters were got for welding different gauges (2mm/8mm) of plates, and they were proved to go quite well in the cylinder butt welding with a V groove. The same or better qualities of welds are expected in the factory.Welding is a complicated process which relates to mass and heat transfer, metallurgy, mechanics; and more knowledge in the field of optics and arc physics are needed to be well understood in the hybrid welding.It is hard to put it into the industry application by mere reseach on theory, or the cost-consuming experiments that sometimes result in vain.The tranditional welding developing mode"theoty-experiment-production"was changed to"theoty-simulation-production"with the rapid development of computer technology in order to solve the time and cost consuming problems.A new analytical temperature field mode was reduced base on the Revolving Gause heat source given by Wu Su by the way presented by N.T. NGUYEN after retrospecting the theory of D. Rosenthal and Rykalin and anlyzed the recent reseach on body heat source, and calculated results using MATLAB shows great agreement with measured results. A simple way for calculating temperature field was developed and a new heat source model was suggested which named"Layered Gauss Body Heat Source Model".Analytical solution is difficult or even cann't be solved without great lose in accuracy. Numerical solutions such as numerical integration, finite difference, FEA (finite element analysis) can solve the problem through numerous calculations which can be done by a high speed computer. One of the best FEA software is ANSYS which can simulate structure, fluid, heat, magnetism, and their coupled field with an easy handling user-computer interface. Basic theory and techniques in temprature field simulation were discussed, and the simulations of different gauges of welds in single and double were investgated based on ANSYS.A Revolving Gause heat source was proved the best heat source model for mid/ thick aluminium alloy plate hybrid welding by comparing the results between the simulations and the experiments. It also provids an efficient way to predict the shape, penetration and width of weldments for the mid and thick Aluminum alloy plate in different welding parameters.