| 摘要 |
PROBLEM TO BE SOLVED: To produce a low-Al soft steel for a strip in which precipitate in a casting nozzle is prevented in billet continuous casting with the small amt. of Ca to be added without the generation of blow holes, without executing ladle refining for the reduction of oxygen using vacuum degassing equipment and LF equipment and without executing electromagnetic stirring in a mold, and to provide a billet continuous casting method for the soft steel. SOLUTION: This soft steel for a strip has a compsn. contg., by weight, 0.01 to 0.3% C, 0.01 to <0.10% Si, 0.1 to 1.0% Mn, 0.005 to 0.020% Ti and 0.0005 to 0.0030% Ca, in which the content of Al is controlled to <=0.005%, and the balance Fe with inevitable impurities. As to the method for producing the soft steel for a strip, casting is executed by a billet continuous casting method, a barrel is set around a pouring flow from a tundish to a mold, and the concn. of oxygen in the barrel is controlled to <=1.0%, or an immersion nozzle is used for the pouring from the tundish to the mold.
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