METHOD FOR DECARBURIZE-REFINING MOLTEN STEEL IN REFINING FURNACE

PROBLEM TO BE SOLVED: To provide a refining method in which the time point of completing decarburization can accurately be judged and the decarburize-refining can suitably be executed neither too much nor too little, at the time of decarburization- refining by charging molten steel inside the closed refining furnace and blowing gas into the molten steel under a prescribed reduced pressure while evacuating the inner part of the refining furnace. SOLUTION: The molten steel 16 is contained inside the closed refining furnace 12 and the gas is blown into the molten steel 1 under the prescribed reduced pressure while evacuating the inner part of the refining furnace 12 to execute the decarburize-refining. In this case, the relation between C content in the molten steel 16 which reduces in accordance with the proceeding of the decarburization and CO concn. in exhaust gas is measured in advance and also, the CO content in the exhaust gas at the time of decareburization-refining is measured, and the decarburize-refining is completed at the point of time when the CO content in the exhaust gas becomes the quantity corresponding to a target C content in the molten steel 16.