| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for remarkably restraining the development of HIC and preventing the clogging of an immersion nozzle regardless of the level of casting speed in the continuous casting of steel having hydrogen induced cracking resistance. SOLUTION: In the continuous casting of the steel having the hydrogen induced cracking resistance, Ca in the molten steel is controlled to 10-50 ppm. In this way, non-metallic inclusion of Al2O3, etc., as precipitate in the steel is reacted with the Ca in the molten steel and removed as slag and the clogging of the immersion nozzle, etc., can be restrained. Further, the blowing of inert gas from the upper nozzle in a tundish, the fixed plate of a sliding gate and the immersion nozzle, etc., are unnecessitated. In this way, the mixture of bubble into the molten steel caused by the inert gas is prevented and the development of the HIC caused by the residual bubble in a cast slab is prevented.
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