Numerical Simulation Of Pulsed Current TIG Welding Arc And Pool

In recent years, pulsed TIG welding is widely used in the production. Comparedwith the constant current TIG welding, pulsed TIG welding involves periodic variationof the welding current, in the pulsed TIG welding, the arc is stable, the input is small,the distribution of arc energy is easy to precisely control, the refined grain structure isconductivetoobtain,the thinplateandthemetal ofpool weldabilitycanbeweld better.Since the more control parameters and the unsteadyweldingprocess, the flow field andtemperature field is more complex than the constant current TIG welding. So throughthe further understanding of the pulsed TIG welding process, we can control andimprove the welding process betterly. In this paper, FLUENT software is used tosimulateandanalyzethearcandpoolofpulsedTIGwelding.First, a two-dimensional axisymmetric model of welding arc under the action ofpulsed current is developed. By use of FLUENT software, choosing appropriateboundary conditions and strongly coupling control equations, pulsed TIG arc issimulated.The changing of arc form, temperature field, temperature and velocityon thearc axis and surface pressure distribution of the workpiece are gotten and analyzed inthe periodic current process; under the action of different peak current, duty ratio andpulsefrequency,thearcpressuredistributionaregottenandanalyzed.Second, based on the set of conservation equations for mass, momentum, energyand the Maxwell equations, a three-dimensional model of pulsed TIG welding pool isdeveloped. By use of FLUENT software, choosing appropriate heat source model,pulsed TIG welding pool is simulated. The cyclical changes of flow field andtemperaturefieldaregottenandanalyzed.ComparedwiththeTIGweldingwhichunderthe action of the average current, the influence laws of pulsed current about the poolsize, temperature field and flow field are obtained. For the width and depth of the pool,under the action of different peak current, duty ratio and pulse frequency, the changesaregottenandanalyzed.In this paper, through the numerical simulation of pulsed TIG welding, which ishelp to further understanding the physical essence, which provide the theoretical basisandguidingroleofreasonablechoiceofweldingmethodandparameters andthefurthermetallurgicalanalysis.