A three-dimensional numerical heat transfer and fluid flow model is developed to understand the temperature distribution and molten pool behavior in a low-current submerged arc welding process. The model solves the equations of the conservation of mass, momentum, and energy along with the volume of fluid method. The volume of fluid method is used to track the shape of the free surface. Further, this paper suggests a flux wall boundary model to simulate flux-wall guided transfer for a single-wire low current submerged-arc welding process. This study simulates how porosity can be trapped in the V-groove joint with a flux-wall guided transfer. The computed weld width and fusion-zone shape are in fair agreement with the corresponding experimental results. (C) 2017 Elsevier Ltd. All rights reserved.