METHOD OF SMELLING STEEL INTO HIGH CLEANED STEEL

• Main Authors: MIYAMOTO KENICHIRO, WATANABE EIJI, NAKAE TAICHI, OHARA NAOYA
• Format: Patent
• Language: English; Japanese
• Published: 23.01.2020
• Subjects: CASTING; CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES; CHEMISTRY; METALLURGY; METALLURGY OF IRON; PERFORMING OPERATIONS; POWDER METALLURGY; PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OFWROUGHT-IRON OR STEEL; TRANSPORTING; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS

To provide a method of smelling steel into high cleaned steel capable of producing high cleaned steel by smelling, in which deoxidized products is removed to be reduced rather than prior art.SOLUTION: When a vacuum degassing treatment is conducted by immersing an immersion pipe 12 of a vacuum degassing device 10 into a molten steel in a ladle 13 in which dissolved oxygen concentration is 40 ppm or less by adding metal Al to the molten steel which has been subjected to primary refining and blowing an inert gas, a treatment of blowing the inert gas of 1.3 to 4.0 NL/min./ton under low pressure vacuum atmosphere of 1.3 kPa or less for 15 to 45 min. in first half, and a treatment of blowing the inert gas of 0.3 to 1.1 NL/min./ton under high pressure vacuum atmosphere of 40 to 67 kPa for 5 to 15 min. in second half, then the molten metal is poured into a tundish 15 in which a dam 17 provided with a molten steel flow channel 21 communicating a molten metal receiving section 18 and a metal discharging section 19 is arranged inside and a height position of an aperture 23 in a side of the molten metal receiving portion 18 of the molten metal flow channel 21 from a bottom 26 of the molten metal receiving portion 18 is set at 0.2 times or less of the molten metal depth of the molten metal receiving portion 18, and induction heated in the molten metal flow channel 21.SELECTED DRAWING: Figure 1 【課題】従来の技術よりも脱酸生成物を除去して低減した高清浄鋼を溶製して鋳造することが可能な高清浄鋼の溶製方法を提供する。【解決手段】一次精錬後の溶鋼に金属Ａｌを添加し溶存酸素濃度を４０ｐｐｍ以下とした取鍋１３内の溶鋼に、真空脱ガス装置１０の浸漬管１２を浸漬し不活性ガスを吹き込んで真空脱ガス処理を行う際に、前半に、１．３ｋＰａ以下の低圧真空雰囲気下で不活性ガスを１．３〜４．０ＮＬ／分／トン吹き込む処理を１５〜４５分間行い、後半に、４０〜６７ｋＰａの高圧真空雰囲気下で不活性ガスを０．３〜１．１ＮＬ／分／トン吹き込む処理を５〜１５分間行った後、受湯部１８と排湯部１９を連通する溶鋼流路２１を形成した堰１７が内部に設けられ、溶鋼流路２１の受湯部１８側の開口部２３の受湯部１８の底面２６からの高さ位置を、受湯部１８の溶鋼深さの０．２倍以下としたタンディッシュ１５に注湯し、溶鋼流路２１で誘導加熱する。【選択図】図１