Numerical Simulation And Stress Analysis Of Double Arc Welding Process Of Magnesium Alloy

Double Electrode Gas Metal Arc Welding(DE-GMAW)is a highly efficient and economical welding method using Tungsten Inert Gas Arc Welding(TIG)and Molten Extremely Inert Gas Protection Arc Welding(MIG).The use of bypass TIG shunt to solve problem that the conventional arc welding in high-speed welding,in order to improve the deposition rate and increase the welding current has led to the parent material heat input get too large.The application of this welding process to the current high-profile magnesium alloy material,can realize the efficient connection of magnesium alloy material.so that magnesium alloy processing technology to meet the needs of more areas.In this paper,based on ANSYS software,the numerical simulation of DE-GMAW double-arc surfacing of AZ31 B magnesium alloy sheet with 2mm thickness is carried out.Combined with DE-GMAW welding experiment,the following researches were done:(1)For the tilted TIG torch,the heat source model suitable for inclined arc is deduced by spatial coordinate transformation,and a double arc heat source model suitable for this paper is established.Using the combination of simulation and experiment,the coupling efficiency of the bypass arc is constantly changed,and the simulated pool size is approached to the experimental value.Finally,the coupling efficiency of the bypass arc is determined.(2)The dynamic distribution and thermal cycling curves of the welding temperature field are obtained by loading the double-arc heat source into the finite element model of the AZ31 B magnesium alloy weld.The influence of the total current and the bypass current on the temperature field is discussed.And the effect of the bypass arc on the heat input of base metal and bath size are discussed.The simulation results are in good agreement with the experimental results,and the correctness of the double arc heat source is verified.(3)The stress dynamic distribution of the DE-GMAW double-arc welding of AZ31 B magnesium alloy was obtained by the thermo-stress indirect coupling method,and the residual stress in the weld direction and vertical weld direction,weld and nearby area were obtained.The simulation results were consistent with the welding theory.(4)The residual stress of the weldment was measured by the small hole release method,and the overall deformation of the weldment was measured experimentally.The experimental results are in good agreement with the simulated values.The results of temperature field,stress and deformation obtained by simulation show that the double-arc welding heat source model established in this paper can accurately reflect the actual heating process and welding result of welding arc.It can provide the correct theoretical data for AZ31 B magnesium alloy DE-GMAW double arc welding process.