To obtain an ingot having good surface after ingot-making in a bottom-pouring ingot-making of molten steel.
In the ingot-making method of the molten steel, with which the bottom part of a molten steel pouring tube 1 and the bottom part of bottom-pouring molds 2A, 2B, 2C are communicated through a runner 2R and the molten steel stream 7 flowing down from the bottom part of a ladle 6 is poured from the upper part of the molten steel pouring tube 1 and flows in from the bottom parts of the bottom-pouring molds 2A, 2B, 2C through the runner 2R to make the ingot in the bottom-pouring molds 2A, 2B, 2C, the stream of the molten steel 7M in the inner part of the molten steel pouring tube is made to low speed by forming the inner diameter of the molten steel pouring tube 1 to the large diameter so as to reduce the variation of the molten steel surface caused by gas boiling in the bottom- pouring molds 2A, 2B, 2C and thus, the float-up of the gas G contained in the molten steel 7M is promoted and the gas quantity flowing in the bottom-pouring molds 2A, 2B, 2C is reduced. Alternatively, a sealing body surrounding the molten steel stream 7 between the bottom part of the ladle 6 and the upper part of the molten steel pouring tube 1 is arranged to prevent the development of the gas caused by the entrapment of atmosphere and the atmosphere oxidizing reaction of the components in the molten steel and thus, the gas quantity flowing in the bottom-pouring molds 2A, 2B, 2C is reduced.
| JPS6171169 | MANUFACTURING METHOD OF FLAT STEEL INGOT |
ARAGAI HAJIME
TSUNO MASAHIDE
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