Improving reliability of modelling heat and fluid flow in complex gas metal arc fillet welds—part II: application to welding of steel

Abstract

In order to improve the reliability of numerical calculations of heat and fluid flow in fusion welding, a model was proposed in part I of this paper to determine the uncertain welding input parameters from a limited volume of experimental data. The application of the model for the complex gas metal arc (GMA) fillet welding of mild steel is reported in this part of the paper. The values of the arc efficiency, effective thermal conductivity and effective viscosity were evaluated as a function of the heat input. A vorticity-based mixing-length hypothesis was also used to independently calculate the values of the effective viscosity and effective thermal conductivity. Good agreement was obtained between the values of these parameters calculated using the two techniques, indicating the effectiveness of the proposed model in improving the reliability of heat and fluid flow calculations in fusion welding. The shape and size of the fusion zone, finger penetration characteristic of the GMA welds and solidified free surface profile computed using the optimized values of the uncertain welding parameters were in fair agreement with the corresponding experimental results for various welding conditions. In particular, the computed values of the leg length, the penetration depth and the actual throat agreed well with those measured experimentally for various heat inputs.