Modeling of temperature field and solidified surface profile during gas-metal arc fillet welding

The temperature profiles, weld pool shape and size, and the nature of the solidified weld pool reinforcement surface during gas-metal arc (GMA) welding of fillet joints were studied using a three-dimensional numerical heat transfer model. The model solves the energy conservation equation using a boundary fitted coordinate system. The weld pool surface profile was calculated by minimizing the total surface energy. Apart from the direct transport of heat from the welding arc, additional heat from the metal droplets was modeled considering a volumetric heat source. The calculated shape and size of the fusion zone, finger penetration characteristic of the GMA welds, and the solidified free surface profile were in fair agreement with the experimental results for various welding conditions. In particular, the computed values of important geometric parameters of fillet welds, i.e., the leg length, the penetration depth, and the actual throat, agreed well with those measured experimentally for various heat inputs. The weld thermal cycles and the cooling rates were also in good agreement with independent experimental data. (C) 2003 American Institute of Physics.