| 摘要 |
PURPOSE: A method for refining molten steel and a method for manufacturing free-cutting steel using the same are provided to insert a re-carburizer in an RH(Reinstahl Huten Werke Heraus) step, thereby minimizing decarburization and deoxidation due to the reaction between carbon and oxygen. CONSTITUTION: A method for refining molten steel includes: a step of preparing the molten steel; a step(S210) of dehydrogenating the molten steel using an RH(Reinstahl Huten Werke Heraus); and a step(S220) of feeding a re-carburizer inside the molten steel when the pressure inside the RH is maintained between 50 and 150 torrs. In the step(S210), the pressure inside the RH is maintained at 2 torrs or less, and inert gas is fed into the RH. In the step(S220), the number of times for feeding the total desired amount of the re-carburizer is multiple. [Reference numerals] (AA) Start; (BB) End; (S210) Dehydrogenation; (S220) Re-carburizer input under a pressure of 50-150 torr and carbon(C) concentration control |
