Effects of a moving weir on tundish flow during continuous-casting grade-transition

Abstract

A moving weir to reduce the time for grade transition is proposed. To investigate benefits of the proposed moving weir, tundish flow subject to various conditions of a moving weir was numerically investigated. First, an optimal travelling path of a horizontally moving weir was determined in a water model. Investigation of various cases shows that the shortest transition time is obtained when new molten steel is injected after the weir returns to its original position after a round-trip. Using this travelling path, the speed of the moving weir was investigated in a real-scale model to determine an optimal speed that stabilizes the surface height while the transition time is minimized. As a result, intermixing of steel with dissimilar grades has been reduced by 14.5 % by using the optimal conditions of the moving weir. Lastly, the performance of vertically moving weirs was assessed by comparing with that of the horizontal counterpart.