Establishment Of The Dynamic Welding Heat Source Model And Study On Numerical Simulation

The welding temperature field contains sufficient information about the quality andproperties of the welded joint, and determines the distortion, residual stresses, and strength, andit is also the foundation of the metallurgical analysis and phase change analysis. To obtain anaccurate temperature field by Finite Element Method (FEM), the importance of a good weldingheat sources model in the analysis of the temperature field has been emphasized by manyinvestigators.Currently, most of the current heat source models are static i.e., not change with time in thewhole welding process, which are not satisfied any more for the dynamic welding process.Regarding the pulsed current gas tungsten arc welding (PCGTAW), in contrast to ConstantCurrent Gas Tungsten Arc Welding (CCGTAW), the fact that the heat energy required to melt thebase metal is supplied only during peak current times, while the background current is set at alevel sufficient to maintain a stable arc, and the characteristic of discontinuity during heatingunder PCGTAW is more obviously when the frequency is low. The objective of the present paperis to develop a more realistic and accurate welding heat source model for PCGTAW.According to the characteristic of PCGTAW, the spinning parabolic shape heat fluxdistribution model was proposed at the background times, and the recommended Gaussian heatdistribution is used at the peak times due to the bell-shaped temperature contour, then thedynamic welding heat source was composed by those two models with a time variable function.In order to assess the validity of the dynamic heat source model, an experiment is conductedwhich the pulsed current gas tungsten arc deposit on the plate. Compared with the resultscomputed by the Gaussian heat source model, the values computed by the dynamic model wereshown to be a more excellent agreement with the experimental values under the same weldingconditions.