Wire Arc Additive Manufacturing (WAAM) is a combination of an electric arc and wire feeding system used extensively in building components and repair operations. The heat transfer, fluid flow and mass transport were investigated in a numerical simulation of WAAM process with dissimilar substrate. Experiments were performed to verify the numerical results. The predicted clad layer (1st layer) profile (width and height) is in good agreement with experiment. The cold wire transfer (CWT) impact on the velocity field and mass transport were predicted around the cold wire immersion inlet in the weld pool (WP). The effect of arc travel speed and wire feed rate on the homogenization process were studied. Both the numerical and experimental results show that the increase of wire feed rate leads to homogenous composition in fusion zone (FZ). The predicted composition distribution in the clad layer and measured concentrations in experiments show a well-mixed region in middle of the clad layer. (C) 2018 Elsevier Ltd. All rights reserved.