METHOD FOR PREVENTING MOLTEN METAL FROM ABSORBING NITROGEN DURING DEGASSING

• Main Authors: KOMIYA TOSHIAKI, MATSUZAWA KAZUHIRO, SUKENARI SHIRO, ITO TOSHIAKI
• Format: Patent
• Language: English
• Published: 14.12.2001
• Edition: 7
• Subjects: CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; METALLURGY; METALLURGY OF IRON; PRETREATMENT OF RAW MATERIALS; PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OFWROUGHT-IRON OR STEEL; PRODUCTION AND REFINING OF METALS; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PROBLEM TO BE SOLVED: To prevent a molten metal from absorbing nitrogen during degassing, by preventing the entry of air by using an immersion tube with a simple structure for degassing. SOLUTION: The method for preventing a molten metal from absorbing nitrogen, when degassing a molten metal by immersing an immersion tube in the molten metal, is characterized by using the immersion tube which is circumscribed by a tubular metal tube to bury in the refractory material of the immersion tube under a circular metal member while providing the circular metal member flatly around a tubular cored bar in the immersion tube to reach an outer surface of a refractory material of the immersion tube; by starting degassing after adjusting a circumference of the above circular metal member to a position of a molten slag on the molten metal; and then during the degassing, by adjusting the circumference of the above circular metal member to a position between 50 mm below from the bottom of the molten slag and 100 mm above from its top, to prevent the molten metal from absorbing nitrogen.