Thermal effects on the flow of liquid steel in continuous casting tundishes

This investigation measures the residence time distributions (RTDs) for an actual steel casting tundish and its one-third scale water model, both during a ladle change and during steady state. The water modeling simulation results confirm that the density difference between the liquid steel in the tundish and the liquid steel entering from a new ladle significantly alters the flow pattern in the tundish. The temperature of the steel entering the tundish is, in general, higher than the steel in the tundish and less dense, as a result. The less dense, hotter steel flows up and over the more dense, cooler steel present in the tundish. A radically different flow pattern develops in the tundish which gradually disappears as the liquid steel from the new ladle eventually replaces the old, at which time, nearly isothermal, steady state conditions are re-established. About 2.5 multiples of the mean residence time are needed to re-establish the steady state, which is usually a significant portion of a ladle casting time.