METHOD FOR MEASURING BULGING RATE AND METHOD FOR RESTRAINING BULGE IN CONTINUOUS CASTING MACHINE

摘要

PURPOSE:To easily detect existence of abnormality in a cast slab at the time of casting by obtaining torque of a motor connected with a driving roll is a continuous casting machine to measure bulging rate. CONSTITUTION:By calculating or measuring the torque TM of motor 3a, 3b...3n connected with each driving rolls 1a, 1b...1n, the torque Ti of the driving roll 3a, 3b...3n is obtd. Successively, a drawing force (fi) of cast slab with the driving roll 3a, 3b...3n is calculated from the obtd. torque Ti. Further, stress of the cast slab is obtd. from the drawing force fi and separately, static pressure P of molten steel is obtd. and thickness (t) of the cast slab is calculated from the equation and the bulging rate t as difference from the standard thickness, is obtd. In the equation, (a): size of smaller part in the width of cast slab and roll pitch, K: constant decided with the width of cast slab and the roll pitch. Further, the bulging rate t at each interval between the rolls is compared with each other and by controlling at least one side of each motor torque TM and cooling water flow rate to the cast slab so that bulging rate is averaged out, the bulging is restrained.