| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for stably producing an extremely low carbon steel having high cleanliness by effectively and stably reducing alumina-series inclusion as a deoxidizing generated material, when the extremely low carbon steel having much alumina-series inclusion as the deoxidizing generated material in comparison with the other steel kinds, is produced. <P>SOLUTION: When the extremely low carbon steel is produced by decarburize-refining molten steel obtained by decarburize-refining in a converter, under lower reduced pressure than the atmosphere pressure in a vacuum-degassing facility, the decarburize-refining under reduced pressure is completed, and then the molten steel is deoxidized by adding metal Al and CaO powder at the same time into the molten steel while adjusting respective supplying speeds so that the ratio of the supplying speed of CaO powder and the supplying speed of metal Al satisfies the range in the following formula (1): 1.6≤Q<SB>CaO</SB>/Q<SB>Al</SB>≤2.4. (wherein, Q<SB>CaO</SB>is the supplying speed (kg/min) of CaO powder and Q<SB>Al</SB>is the supplying speed (kg/min) of metal Al). <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
