Meso-scale modeling through the use of a granular-type model is a key new tool for predicting solidification-related defects. In the present study, the application of a granular-type model to welding microstructure is presented, along with application challenges and solutions. This new model can simulate the solidification of a weld pool at the mesoscale, i.e. both solid grains and liquid are included. Consequently, the behaviour of the semisolid structure within the weld pool can be studied. By means of this 3D meso-scale model, the continuous network of liquid channels that forms at the last stages of solidification have been investigated, allowing for prediction of the variation in the distribution of liquid channel width as a function of welding parameters.