PROBLEM TO BE SOLVED: To provide a method for accurately producing a steel having high cleanliness and containing a very little harmful non-metallic inclusions remaining in molten steel with a necessary and sufficient process.;SOLUTION: A killing time is set in accordance with an inclusion diameter which is desired for a product at the completion of refining, and if the maximum value of a grain diameter of the inclusion in the molten steel in a refining finishing process is obtained by using an inclusion sensor and this maximum value of the grain diameter is greater than the diameter of the inclusion desired, the method uses killing process to obtain the high cleanliness steel. In this method for producing the high cleanliness steel, according to the maximum diameter of the inclusion desired for the product, the killing time in a ladle-refining is secured to t sec ± 10% in formula (1), t=1.8×106×h/D2, where t is killing time (sec); h is the depth of molten steel (m) in the ladle, and D is the maximum diameter (μm) of the inclusion desired for the product.;COPYRIGHT: (C)2008,JPO&INPIT
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