Abstract: A method of manufacturing a ferritic stainless steel containing an ultra low level of carbon concentration in molten steel within time shorter than existing technology by controlling content, appropriate composition, and liquid-state fraction, etc., of Cr2 O3 in slag to maximize vacuum decarburization refining efficiency, the method comprising: tapping molten steel to a ladle in a non-deoxidized state after pre-decarburization and denitrification in an ARGON OXYGEN DECARBURIZATION refining furnace and then removing non-deoxidized slag; placing the ladle in a vacuum furnace, reducing pressure and then blowing-in oxygen gas from the upper of the molten steel through a lance; creating Al2 O3 by injecting Al at point of time of beginning of oxygen blowing; forming CaO—Al2 O3 —Cr2 O3 —MgO-based slag by injecting calcium oxide at point of time of completion of the oxygen blowing; and supplying inert gas through a porous plug on a bottom of the ladle.

Abstract: The present invention relates to a method of manufacturing a ferritic stainless steel containing an ultra low level of carbon concentration in molten steel within time shorter than existing technology by controlling content, appropriate composition, and liquid-state fraction, etc.

Abstract: The present invention relates to a method for reducing to metallic chromium the chromium oxide material found in slag formed in an electric arc furnace during the process of making stainless steel in that furnace. The chromium oxide content of the slag can be effectively reduced to a relatively low concentration by maintaining the slag in a liquid phase while at the same time blowing into the furnace via a carrier gas certain amounts of powdered aluminum dross. In particular, powdered aluminum dross can be blown into the furnace in amounts ranging from about 10 to 20 kg of dross per ton of molten steel in the furnace. Alternatively, powdered aluminum dross can be blown into the furnace in a thrown-in amount which satisfies the equation: 0.5?[Thrown-In Al dross (ton)×100]/[Slag in Furnace (ton)×Cr2O3 (wt %)]?1.0. Via such a method used during the stainless steel making process, the recovery of valuable chromium and the rate of chromium oxide reduction can be increased.