Control Method of Secondary Cooling Water for Bloom Continuous Casting on the Basis of Temperature Estimation

Abstract

Dynamic control of secondary cooling water for bloom continuous casting (C. C.) is described. This method is based on online estimation of bloom temperature by one dimensional heat transfer model. Field data, such as molten steel temperature, actual water flow, casting speed are used in the estimation. The heat transfer model is updated by adaptive control of heat transfer factor to equalize calculated temperature with measured one. To attain closer control, feed forward control method is applied. Bloom temperature is predicted by the updated model and appropriate water flow for each zone is determined by the difference between predicted temperature and aimed one. Since cooling process is considered in this method, surface temperature is controlled at the aimed one not only in the case of steady casting speed and also in the case of transient casting speed. Therefore, this method compensates for the problems of usual cascade control method.
Dynamic control system is introduced to bloom C. C. line No. 3 in Kobe Works and it is confirmed that change of temperature has been remarkably reduced and surface cracks have been prevented compared with usual control.