METHOD FOR PREVENTING ATMOSPHERIC AIR-LEAKAGE IN VACUUM-DECARBURIZE-REFINING

• Main Authors: KONDO MASAAKI, ONISHI KENJI, KANEYASU TAKAYUKI
• Format: Patent
• Language: English
• Published: 05.10.2006
• Subjects: BLASTING; CHEMISTRY; DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS,IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KINDOF FURNACE; FURNACES; HEATING; KILNS; LIGHTING; MECHANICAL ENGINEERING; METALLURGY; METALLURGY OF IRON; OVENS; PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OFWROUGHT-IRON OR STEEL; RETORTS; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS; WEAPONS

PROBLEM TO BE SOLVED: To provide a method for preventing the atmospheric air-leakage in a vacuum-decarburize-refining with which a low nitrogen steel, further extremely low nitrogen steel is easily produced by improving the sucking efficiency of the air in a refractory at more than the conventional one to restrain the mixture of the nitrogen into molten steel. SOLUTION: When the vacuum-decarburize-refining for molten steel 14 is performed by reducing the pressure in an immersion tube 12 while immersing the lower end part of the immersion tube 12 set with the refractory 11 on the circumference of a core metal 10 into the molten steel 14 in a ladle 13; in the method for preventing the atmospheric air-leakage by restraining the mixture of the flowing air from the outer part of the immersion tube 12 into the molten steel 14, an air passage 16 is arranged at the interval between the refractory 15 set at the inside of the core metal 10 in the immersion tube 12 and the core metal 10 or in the inner part of the refractory 15 set at the inside of the core metal 10 and then, the pressure in the air passage 16 is reduced. COPYRIGHT: (C)2007,JPO&INPIT