Simulation Of Arc And Droplet Transfer Behavior In MIG Welding Based On Fluent

MIG welding has become the first choice for industrial welding methods due to its high efficiency and wide application.Improving the process characteristics of MIG welding is an important direction to improve the welding quality.It replaces the traditional repeated large number of welding tests by simulation to optimization parameters and processes.This technology is also getting more and more attention.On the other hand,the efficiency and quality of welding are directly affected by the characteristics of the arc during the welding process and the advantages and disadvantages of the droplet transfer.It is increasingly important to study the welding arc and droplet transfer behavior.In this paper,the Fluent software is used to simulate the MIG welding arc under the protection of argon and helium.By setting reasonable boundary conditions during the simulation,the simulation results can achieve high precision.There is no software measurement error.The results of simulation can obtain a variety of variables such as the temperature field of the arc,the plasma flow field etc,which is convenient for multi-angle analysis,and can compare and analyze the arc behavior under the protection of argon and helium.According to the experimental conditions and the actual welding process,in the calculation process,the influence of droplet transfer and sheath on the arc is neglected,and a two-dimensional axisymmetric arc mathematical model that meets the conditions is established,which passes the three major fluid equations and Maxwell's equations.On the basis of plasma-related knowledge,reasonable boundary conditions are set,and reasonable calculation methods are selected to simulate the presence or absence of radiation and argon and helium arc under different currents.The results of the MIG welding arc simulation under the protection of argon and helium show that the arc temperature will decrease significantly when considering the radiation,and the arc arc will shrink,which is more in line with the actual welding process.The results of argon arc and helium arc at different currents shows that at the highest temperature of the arc,the argon arc temperature is higher,but the helium arc has a higher temperature region.The highest temperature of the arc is directly below the electrode,and the temperature is gradually downward decrease.In the vicinity of the axis of the arc model,the high temperature region of the arc appears,that is the arc column region.In the radial direction,the center temperature of the arc column region is the highest,and the ambient temperature is gradually decreased.The arc spectrum of the MIG welding process under argon protection was collected by the spectroscopy software.It was found that the main lines in the MIG process were Fe and Ar lines,which was highly consistent with argon and iron vaporduring the simulation.In addition,the radiant energy distribution in the FeI line aggregation region is also in good agreement with the molar distribution of iron vapor in the simulation results.Based on the simulation study of the arc,the MIG welding droplet transfer simulation theory is deeply understood and studied.The MIG welding droplet transfer model is also based on the theory of magnetohydrodynamics.It uses multi-phase flow,based on the fluid volume function(VOF),taking the effects of gravity,electromagnetic force,surface tension,and plasma flow into consideration during the droplet transfer process.The surface tension(CSF)model treats the surface tension and performs the droplet interface reconstruction by the VOF method.The droplet transfer at 180 A and 210 A was simulated.The process of droplet formation,growth and detach was studied.It was found that when the current increased,the droplet size became smaller and the droplet transition frequency increased.The simulation results are reasonable.