A reagent for removing nitrogen from molten steel and the refining method using it at RH process

摘要

PURPOSE: A reagent for removing nitrogen from molten steel is provided to actively remove nitrogen in molten steel through chemical reaction, and a method for refining molten steel using the reagent at RH process is provided. CONSTITUTION: The reagent comprises 2 to 10 wt.% of Na2CO3; and a balance of CaC2 and other inevitable impurities. In a method in which molten steel(1) is second refined by refluxing molten steel of ladle(2) into vacuum tank through ascension pipe(4) and descension pipe(5) of RH facility, the reflux type vacuum degassing refining method is characterized in that molten steel is refined by injecting 0.01 to 0.03 kg of the nitrogen removing agent per ton of molten steel into molten steel contained in the vacuum tank of the RH facility, wherein the nitrogen removing reagent is pellet having a diameter of 2 to 10 mm and thickness of 1 to 5 mm, and wherein reflux of a mixture of the molten steel and nitrogen removing reagent is performed for 3 minutes or more right after injecting the nitrogen removing reagent into molten steel.