The geometry of the tundish is very important for the stability of the continuous casting process and for the quality of the final product. In this work criteria used for the optimization of fluid-dynamic behavior in tundishes, some based on the direct experience, some based on the extensive use of computational fluid dynamics, are presented. Some criteria can be listed: a) steel temperature to the casting lines, b) inclusions behavior, c) trapping of the cover dust, d) erosion of the tundish refractory, etc.. The determination of these criteria allows to optimize the geometry of the tundish very quickly, by changing the configuration accordingly to the specific needs arising from the disposal of the casting plant and from the productivity. The transient simulations executed on the tundish optimized geometry allow to investigate the fluid-dynamic behavior for any technology process involving the tundish filling with a new type of steel and the mixing with the previous. The modeling approach is completed by the study of fluid dynamics in the ingot mold and by the prediction of the steel composition at the product section during solidification. Finally it is presented a summary of an analytical model, based on the tundish subdivision into interconnected elementary volumes, having uniform concentration, and defined on the basis of the specific behavior observed in the optimized geometry. Such model describes the variation of composition from the discharge into the tundish until the exit of each line, hence supplying a function which is implemented in the process automation. In conclusion, the fluid dynamics analysis made possible the calibration of a model which allows to define an appropriate technological practice for several sequences of change of the steel types, minimizing production losses. |
22-23 October 2012 Pacengo del Garda 
