Refining method of molten steel for producing ultra low carbon steel

摘要

The present invention relates to a method for refining molten steel in the furnace refining process of the steelmaking process to manufacture ultra-low carbon steel, which can easily remove the carbon component in the molten steel and effectively prevent the temperature drop of the molten steel as well as achieve a stable operation To provide a method of refining molten steel, which has a purpose.;The present invention relates to a method for refining molten steel in order to produce ultra-low carbon steel in an RH vacuum degassing apparatus including a deposition tube consisting of a vacuum tank, a rising reflux pipe, and a down reflux pipe, including a straight portion and forming a supersonic jet stream. Installing a plurality of gas injection lance nozzles comprising an inner tube and an exterior having a neck formed thereon, the sidewalls of the vacuum chamber of the RH vacuum degassing apparatus such that gas is injected toward the molten steel in the vacuum chamber; Supplying reflux gas to the rising reflux tube while reducing molten steel received timing ladles and reducing the internal pressure of the vacuum tank so that the molten steel received at the teaming ladle is raised into the vacuum chamber along the rising reflux tube; And when the internal pressure of the vacuum chamber reaches 150 mbar or less, injects oxygen or oxygen-containing gas through the inner tube until a maximum decarburization is completed at least 3 minutes from the start of the injection to form a jet stream toward the molten steel in the vacuum chamber. Main point is a method for refining molten steel for producing ultra-low carbon steel comprising the step of spraying the cooling gas for cooling the inner tube through the end of refining.