The Gaussian heat source has been widely used to simulate the heat flux of the welding arc, and applied to calculating the temperature distribution of a workpiece. The conventional Gaussian heat source of the free-flight and short-circuit modes are modified in this work by decomposing the total arc heat sources into heat sources of the cathode and metal transfer. In case of free-flight mode, the efficiency and distribution of each heat source are determined analytically for the globular and spray modes. The characteristics of the heat source in the short-circuit mode are different from those in the free-flight mode because of periodic occurrence of arcing and short-circuiting. The Gaussian heat source model of the free-flight mode is modified to simulate the heat flux of the short-circuit mode. The temperature distribution and weld geometry are calculated using the finite element method, and the predicted results show better agreements with the experimental results than those using the previous Gaussian heat source.
