UBC Theses and Dissertations
Control of spray cooling in the continuous casting of steel Baptista, Luis Antonio de Souza
The basic principles of spray control during casting speed changes in the continuous casting of steel have been studied. The normal spray control practice in which water flow in the sprays is made proportional to the casting speed has been found to be completely inadequate from the standpoint of controlling the surface temperature of the strand. A computer model based upon the principle of controlling the sprays as a function of the age of the metal passing through the machine has been developed. The model predicts both the average local residence time and water flux in a spray zone for any casting speed change. An accompanying heat flow model has also been developed for characterization of cooling rates and simulation of the effects of spray control practices on the surface temperature of the strand. The control model has been used for the development of a new spray control practice in an industrial slab caster. Tests have been performed both using the new practice and the normal spray control practice. Although, a complete verification has not been possible at this time, the model appears to realistically predict the thermal requirements of the strand during casting speed change. The necessity for automatic control of the sprays has become evident during the development of the present work. The principles of automatic control of the sprays have been studied and the control model adapted for this purpose. It has been shown that a true automatic control of spray cooling can be attained using the mathematical model for spray control.
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