A Model Analysis of the Temperature Variation of Molten Steel in Continuous Casting Tundish

Abstract

In order to obtain the temperature variation of molten steel in tundish during the teeming of continuous casting, a mathematical model which consists of heat balance of molten steel in tundish has been developed. The results calculated from this model were compared with the data of operation of the bloom caster at the Mizushima Iron Works, and it was proved that this model was useful for predicting the temperature variation of molten steel in tundish.
Applying this model, the effects of the operating conditions and of a size of tundish were considered, and the following results were obtained.
(1) Concerning the preheating conditions of refractory for preventing the temperature drop of molten steel, preheating temperature is more important than preheating time. A rise of 200°C in preheating temperature decreases the temperature drop of molten steel in tundish by 10 to 15°C in usual operation.
(2) A slag layer of 15mm thick is adequate as an insulator for heat loss from molten steel to atmosphere.
(3) Molten steel of 600mm depth in tundish is necessary to the stabilization of teeming temperature.(4) To prevent the temperature drop of molten steel, the ratio of width to depth of tundish is desirable to be nuity.
(5) The rate of temperature drop in the pouring stream from ladle to tundish is desirable to be 0.3-0.5°C/min for the stabilization of temperature throughout the teeming period.