Refined-smelting ladle furnace carbon control deep desulphurization method for ultra-low-carbon steel production

Abstract

The invention discloses a method for controlling carbon and deep desulphurization by a refined-smelting ladle furnace in the production of extreme low carbon steel, pertaining to the technical field of ladle refining. The technology of the invention is that the amount of roughing slag of a converter is controlled and the thickness of the slag is 30 mm to 60mm; the temperature of molten steel in an LF furnace ranges from 1590 DEG C to 1640 DEG C and the content of Al in the steel is equal to 0.05 percent to 0.09 percent; 6 to 12 kg/ton of refining slag with high basicity and 0.4 to 1.0 kg/ton of Al granules are added; the flow of bottom-blowing argon gas is controlled during the rapid deep desulphurization refining process. On the condition that no electrode is available, argon gas with mass flow of 6 to 8NL/ (min question mark t) is adopted for melting slag. After slag melting, the electrode is arranged to control the flow of argon gas to 4.8-6NL/ (min question mark t) and carbon pickup of the molten steel occurs; when the refining is completed, the oxidizability of steel slag (FeO+MnO) is required to be less than or equal to 1.0 percent and the weight percentage of alkalinity of (CaO)/(SiO2) is equal to 5.5 to 8.0. The method of the invention has the advantages of solving the problem of carbon pickup during the refining in the LF furnace and controlling the weight percentage of carbon increment within 0.015 percent, thereby realizing rapid deep desulphurization with the content of sulfur[S] which is less than or equal to 0.0010 percent after desulphurization, and shortening the smelting time of the LF furnace.

Description

technical field [0001] The invention belongs to the technical field of ladle refining, and in particular relates to a ladle refining furnace controlled carbon deep desulfurization method for producing ultra-low carbon steel, in particular to performing deep desulfurization of molten steel while controlling C increase in smelting high-grade ultra-low carbon steel. Background technique [0002] Except for a few special steel types, sulfur is a harmful element in steel, and it is easy to generate FeS with a low melting point, which causes hot brittle cracks in steel during hot rolling and welding; it is also easy to form sulfide inclusions in steel, reducing the ductility of steel Strength and toughness, especially impact toughness. When the sulfur content is high, the HIC corrosion resistance is greatly reduced. With the increasing demand for high-grade steel, the quality requirements for steel are more stringent, and the composition is required to be ultra-high purity in the...

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Problems solved by technology

[0005] The object of the present invention is to provide a ladle refining furnace controlled carbon deep desulfurization method for the production of ultra-low carbon steel, which solves the problem that deep desulfurization cannot be carried out in order to prevent the increase of C in the smelting of high-grade low-carbon steel. How to control the increase of C in steel production while realizing rapid and deep desulfurization treatment in LF furnace, so as to meet the requirements of ultra-low carbon and low-sulfur steel production

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