SPECIFICATION FRAMEWORK FOR CONTROL OF THE SECONDARY COOLING ZONE IN CONTINUOUS-CASTING

A model describing heat transfer in the secondary cooling zone (SCZ) o f a continuous easter is derived. In order to reduce the defects arisi ng from improper cooling in the SCZ of a continuous easter, a simple o pen-loop control strategy is proposed and evaluated. This means that w ith the aid of an equivalent numerical model of the SCZ, the heat tran sfer coefficients are found which deliver an ideal or near-ideal tempe rature profile along the midface of the strand. The temperature profil e is specified by the user, and strongly depends on characteristics of the steel and physical constraints of the water cooling system of the continuous easter. Two examples highlighting the open-loop control ap proach are shown for a low carbon 14 cm x 14cm biller easter. Simulati ons show that a temperature profile can be achieved with open-loop con trol that differs only slightly from the specified temperature profile . Casting speed, rollers and clogged sprays are the main disturbances that can cause the temperature profile to deviate from ideal. The infl uence of these disturbances is shown.