NUMERICAL-SIMULATION OF THE EFFECT OF GRAVITY ON WELD POOL SHAPE

Understanding the physical phenomena involved in the welding process is of substantial value to improving the weldability of materials. The intense heal and the are inherent in fusion welding make direct experimental observation of the weld pool behavior rather difficult. Thus, numerical models that can predict the processes involved have become an invaluable tool for studying welding. One of the major factors affecting the motion within the molten weld pool is the gravity-driven buoyancy force. This force can act to oppose or enhance the Marangoni and/or electromagnetic driven convective flow within the weld pool. To study the effect of gravity on weld pool processes, a series of numerical simulations was performed. It was found that higher gravitational fields tend to enhance the convective flow within the weld pool and thus affect the heat transfer, the depth and width of the two phase region, and the pool depth-to-width ratio.