Model studies of plasma heating in the continuous casting tundish.

A room temperature water model of a tundish was design, constructed and operated. The model was equipped with a steam heating system that simulates that simulates the tundish plasma heating systems operated by some of the more modem continuous casting plants. Similarity between steam heating in the water model and plasma heating in the tundish has been established. A dimensionless criterion was developed to validate the simulation experiments and its represented by the plasma heating number. Using this similarity criterion plasma heating can be simulated by steam heating in an appropriately designed water model. A theoretical dispersion model has been formulated for the flow through the tundish and the parameters in this model determined from the results obtained from residence time distribution measurements. A conductivity method was used, a highly conducting species being injected at the inlet point and changes in conductivity monitored at the exit. Measurements were also made of the changes in temperature at the exit resulting both from changes in temperature of the inlet stream and from the use of steam heater system. A stable inverse heat conduction method has been developed in which the measured and estimated temperature are analysed in terms of a steady components of short duration. A finite difference method has been used to predict the effect on a thermocouple temperature of the deviatory components of the liquid steel temperature. The incorporation of these predictions into look-up tables has allowed an algorithm to be developed thet can deduce the current deviatory component of the steel temperature from the thermocouple response.