| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for continuously casting a small cross-sectional cast billet, in which the inner quantity improving effect of the cast billet is developed by stably and surely reducing the generation of a center porosity at the center part of the cast billet regarding to many kinds of steel. <P>SOLUTION: In the continuous casting method for casting the billet having ≤500 cm<SP>2</SP>cross sectional area by pouring molten steel into a mold using a cylindrical immersion nozzle provided with a single hole, the molten steel surface level in the mold is measured by using an eddy current type molten steel surface level sensor in the mold, and based on this measured value, the molten steel surface level is controlled and also, the fluidity of the molten steel in the mold is adjusted by giving an electromagnetic stirring and further, a solidifying end stage cooling zone is formed in the range of a prescribed length from a meniscus, and the casting speed is adjusted so that the range of 0.3-0.99 solidified phase ratio at the center part of the cast billet enters in the solidifying end stage cooling zone, and a cooling water quantity at a secondary cooling zone, a cast billet surface temperature at the inlet of the solidifying end stage cooling zone and a water flowing density of the cooling water at the solidifying end stage cooling zone, are controlled appropriately. <P>COPYRIGHT: (C)2009,JPO&INPIT |
