PURPOSE: To prevent formation of a gap between the surface of a steel ingot and water cooled copper plates and formation of an internal defect in the steel ingot by sandwiching a set of opposed long side molds inscribed with the water cooled copper plates with a set of short side molds and pressing the long side molds from the outside to the inside.
CONSTITUTION: When a molten steel 16 is charged from a charging pipe 18 through a runner 20 into a casting mold, the molten steel begins to start solidifying from the part in contact with the inside wall of the casting mold and double molding boards 14, thus forming a solidified shell 16A toward the lower part from a heat retaining layer 15 on the top surface. A gap is formed between the shell 16A and water cooled copper plates 6 owing to shrinkage of the shell 16A upon completion of charging of the steel 16. Tightening cylinders 8 of short side molds 4 are then loosened and pressing devices 10 of long side molds 2 are acturated to press the opposed molds 2 from the steel ingot from the outside to the inside. The gap is formed again even after the pressing operation of the molds 2 and the plates 6A and therefore the pressing operation is performed continuously or repeated intermittently several times to eliminate or minimize the gap, thereby accelerating the solidifying speed.
EMOTO KANJI
MATSUKAWA TOSHITANE
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