PREDICTION OF SURFACE DEPRESSION OF A TUNGSTEN INERT-GAS WELD POOL INTHE FULL-PENETRATION CONDITION

A three-dimensional model is set up to predict the surface depression of a tungsten inert gas (TIG) weld pool in a full-penetration conditio n in order to find out the relation between pool depression-cmd weld p enetration. It solves pool surface depression,fluid flow and heat tran sfer simultaneously and determines the configuration of a weld pool su rface based on the dynamic balance among are pressure, pool gravity an d surface tension at the deformed weld pool surface. In the numerical simulation, difficulties associated with the irregular shape of the de formed weld pool surface and the liquid/solid interface have been over come by adopting a boundary-fitted non-orthogonal curvilinear coordina te system. A series of data about pool surface depression under differ ent TIG welding conditions are obtained. The validity of the model is verified through TIG welding experiments.