METHOD FOR AUTOMATICALLY OPENING HOLE IN MOLTEN METAL BASIN PART IN TUNDISH

PURPOSE:To improve the low quality of a cast slab at the initial stage of casting in the continuous casting and to eliminate a forced hole opening work having high danger. CONSTITUTION:This automatic hole opening method in molten steel basin part in a tundish 1 uses the tundish 1 provided with a sliding nozzle 3 at the outer bottom part, and after the received molten steel is held in long time at the initial stage of the casting start, the hole is naturally opened according to the hole opening of the sliding nozzle 3 to pour the molten steel into a mold. The nozzle refractory of the upper nozzle 2, etc., before receiving the molten steel, is beforehand held at the high temp. condition of >=950 deg.C and successively, the molten steel is received to the prescribed quantity and also inert gas F is injected from the upper surface of a sliding plate 5 in the sliding nozzle 3. The sequential continuous casting of the different kinds of steels for executing the adjustment to alloy components in the tundish and the hot repeated use of the tundish in the condition of remained high temp. of the nozzle part refractory after disposing the steel slag, etc., in the tundish, are efficiently executed and the productivity of the continuous casting can be improved.