Abstract
Gas tungsten arc welding with an external magnetic field is proven to suppress weld defects while improving welding speed. A three-dimensional numerical model that considers interactions among the arc plasma, weld pool, metal vapor, and external magnetic field is developed. The influences of the external magnetic field and metal vapor on arc and weld pool behaviors are investigated. The external magnetic field has an important influence on the arc shape and the weld pool flow field. The metal vapor increases the arc radiation loss but decreases the conductivity and local current density.