The purpose of this project is to model the transport phenomena (heat transfer, fluid flow, and current flow) in a gas tungsten arc welding (GTAW) process using COMSOL Multiphysics. The model development will start with developing two separate models - an arc model and a weld pool model and end with an integrated arc - weld pool model to simulate the interaction between the arc and the weld pool. The integrated arc-weld pool model will be used to study the effects of some welding process parameters, such as the anode materials, the arc length, and the shielding gas, on the final weld quality.