METHOD FOR CONTINUOUS-CONTINUOUS CASTING TWO OR MORE STEELS IN ONE TUNDISH BY INJECTING ARGON GAS AND MIXED BAND AND CONTROLLING CASTING SPEED

摘要

PURPOSE: To provide a continuous-continuous casting method of two or more steels in the same tundish, wherein two or more steel slabs are produced in one tundish without exchange to reduce slab manufacturing cost by increasing the number of continuous-continuous castings and improve productivity and prevent safety accident by suppressing trouble during casting operation. CONSTITUTION: In a continuous-continuous casting method for continuously producing slabs by supplying refined molten steel into tundish(8) using a ladle(1) and supplying the supplied molten steel of tundish into a mold(10) of continuous casting machine, the continuous-continuous casting method of two or more steels in the same tundish comprises the steps of simultaneously reducing casting speed of the mold, closing a molten steel outlet of the tundish by a tundish molten steel outlet opening and closing means, supplying an inert gas into the molten steel outlet and injecting a mixed band(30) onto the upper surface of molten steel of the mold so that the mixed band covers molten steel of the mold if 2/3 or more molten steel in the tundish supplied from the ladle is supplied to the mold of the continuous casting machine when type of molten steel of the ladle to supplied to the tundish is different from type of molten steel in a waiting ladle that has to be continuously supplied to tundish afterwards; ascending the tundish to the upper side in succession; and stopping supply of the inert gas while supplying molten steel in the waiting ladle into the tundish, opening the closed molten steel outlet of the tundish, thereby supplying molten steel of the tundish into the mold so that molten steel is cast, and turning back the ascended tundish to the original position at the same time.