Heat transfer and fluid flow in a weld pool had been simulated for several decades, which underwent from theoretically analysis
to numerical solutions. Because of the complexity of the welding process, many ideal assumptions were made to simplify the question. This makes the solution somewhat not complied with the practical conditions. In previous papers, the
current distribution in the weld pool is assumed as axi-symmetrical, and so does the electromagnetic forces, which plays an important role in determining the fluid flow field. Actually the current
Distribution is different from the assumption. In this paper; a three dimensional current distribution in Gas Tungsten Arc Welding (GTAW) process is performed. The current density distribution field is evaluated by numerically solving Maxwell's equations in the domain of the workpiece. In the boundary condition, the current density on the top surface is assumed as Gaussian distribution. Results show that the current distribution in GTAW is not axi-symmetrical, and the relative location of the torch and the earth clamp influence the current distribution greatly.