METHOD FOR CONTROLLING SURFACE TEMPERATURE OF CONTINUOUS CAST SLAB

PURPOSE:To make the prescribed value or less of surface recuperative heat quantity on a cast slab itself and to produce the sound cast slab by obtaining the max. cooling water flow rate so that the presuming recovered heat quantity becomes the prescribed value or less and controlling the cast slab temp. taking the cooling water flow rate of the max. cooling water cooling flow rate or less as the set value. CONSTITUTION:The cast slab is divided into meshes based on thickness direction, besides steel kind, size thereof, length of secondary cooling zone and cooling intensity, etc., to calculate the cast slab temp. with enthalpy method. Whether deterioration of the quality of internal crack, etc., is developed or not with the recovered heat quality, is decided from relation equation between the temp. just before recuperating heat and the recuperative heat quantity on the cast slab. In the case, the recuperative heat quantity is the temp. affecting the cast slab quality, the set water flow rate is increased, and the temp. just before recuperating heat and the cast slab temp. after passing through secondary cooling zone are again obtd. Then, by repeating this operation until the temp. reaches the temp. at which the temp. does not affect the cast slab quality with the recuperative heat quantity, the set water flow rate is obtd.