NUMERICAL SIMULATION OF MARANGONI CONVECTION IN ACTIVATED TIG WELDING

摘要

The TIG welding process allows to obtain high quality welds for most of metals and alloys. But the weak efficiency of the electric arc limits the autogenous welding in one single pass to low thicknesses. The Activated-welding (A-TIG) is an original way which leads to extend the applications of TIG process to thicker pieces by adding activating flux. This paper presents a rather simple model to describe the double action of activating flux. In the electric arc, charged particles coming from flux dissociation participate to the heat input constriction. The weld pool is animated principally by Marangoni currents, the participation of tension-active elements leads to inverse these currents. This model is implemented in a FEM code. Results of each contribution are discussed and compared to evaluate the preponderance of both actions.