A method for reducing nitrogen addition in molten steel during continuous casting

Abstract

The invention relates to a method for reducing the nitrogen increasing amount of molten steel in the continuous casting process. The method comprises the steps that a three-layer sealing structure isadopted at the combined position of a ladle long nozzle and a steel ladle drain hole, the outermost layer of the sealing structure is a traditional first sealing gasket layer, the middle layer is a second sealing gasket layer, and the innermost layer is a plaster sealing gasket layer; the lower middle portion of the ladle long nozzle is in a horn shape, and the inner diameter of the ladle long nozzle is gradually increased from middle to bottom; a layer of low-melting-point covering agent is sprayed to the surface of a tundish; in the installing process of the tundish, a gap between the wall of the tundish and the cover of the tundish is sealed with refractory mortar, and inert gas is introduced between the cover of the tundish and the liquid level of the molten steel of the tundish. The three-layer sealing structure is adopted at the combined position of the ladle long nozzle and the steel ladle drain hole, the low-melting-point covering agent can be kept in the complete liquid stateunder the molten steel temperature, and the anti-oxidation effect is improved.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, in particular, the invention relates to a method for reducing the amount of nitrogen added to molten steel during continuous casting. Background technique [0002] In the continuous casting process, the ladle long nozzle is generally used as the molten steel circulation channel between the ladle and the tundish. The flow velocity in the long nozzle is about 1-3 m / s, and the fast-flowing steel flow acts as a "jet pump", which produces a huge suction force on the surrounding air and will suck the surrounding air into the molten steel. If the seal between the long nozzle and the ladle outlet is not tight, serious secondary oxidation of molten steel will occur. At present, a gasket and argon gas are used to seal between the ladle lower nozzle and the ladle long nozzle. The gasket seal is to put an aluminum silicate fiber with a thickness of about 5mm between the ladle lower nozzle ...

AI Technical Summary

Problems solved by technology

[0004] During the casting process of molten steel in the tundish, a covering agent needs to be sprinkled on the surface of the molten steel in the tundish. The covering agent can play the role of isolating the air and absorbing the inclusions floating from the molten steel. However, the covering agent Heat dissipation in contact with air will cause crusting on the slag surface, and the surface of the covering agent after crusting is prone to cracks due to uneven shrinkage.

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