Composite titanium removing agent and smelting method for reducing titanium content of molten steel

Abstract

The invention relates to a composite titanium removing agent and a smelting method for reducing the titanium content of molten steel. The composite titanium removing agent comprises, by mass, 30%-40%of FeO2, 40%-50% of CeO2 and 10%-30% of CaF2, wherein the particle size D50 of all the components is smaller than or equal to 50 mm. During molten iron pretreatment desulfurization, the composite titanium removing agent is added into molten iron, double slag smelting is adopted during converter smelting, active lime, soft burnt lime and iron ore are added in the early stage of smelting, and activelime and iron ore are added during latter semisteel smelting; and before converter tapping, CeO2 is added to the bottom of a molten steel refining ladle, and after the molten steel enters a tundish,CeO2 is added during each time of casting. The titanium content in the molten steel can be controlled in the whole smelting process, and the target that the mass fraction of titanium in finished steelis lower than 0.001% is achieved.

Description

Technical field [0001] The invention relates to the technical field of steelmaking, in particular to a composite detitanizer and a smelting method for reducing the titanium content of molten steel. Background technique [0002] Titanium in molten steel can combine with nitrogen to form TiN inclusions. TiN inclusions are a harmful inclusion for many steel grades. For example, TiN inclusions have an important effect on the magnetic properties of non-oriented silicon steel, which is mainly manifested in suppressing grain growth. Large, promote lattice distortion, hinder magnetic domain rotation and domain wall movement, and are harmful inclusions that deteriorate the electromagnetic properties of non-oriented silicon steel. Therefore, most non-oriented silicon steel manufacturers strictly control the content of Ti and N in the steel; When cord steel is smelted, brittle TiN inclusions with poor deformability will be produced. If they are not controlled, the subsequent drawing and twi...

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Problems solved by technology

[0004] Chinese patent with publication number CN1603032A "Preparation method of nano-detitanium agent for bearing steel", Chinese patent with publication number CN100465293C "dispersion method of nano-detitanium agent for bearing steel in molten steel", Chinese patent with publication number CN1721556A "The Addition Method of Bearing Steel Nano-Titanium Removal Agent in Liquid Steel" records a nano-iron alloy material titanium removal agent and its use method, including the preparation of nano-scale titanium removal agent, cored wire preparation, dispersion and addition process, etc.; Publication No. CN107130084B of the Chinese patent "A Cleaning Agent for Liquid Steel De-inclusions" describes a cleaning agent whose main components are metal aluminum, lime powder, silicon carbide powder, titanium dioxide and biomass. The purpose of reducing the titanium content of molten steel is achieved by promoting the floating of titanium-containing inclusions in molten steel; all of the above methods have achieved the reduction of titanium content in molten steel at a certain stage, but steelmaking is a long-term process. The titanium content is fully controlled in the whole process, and titanium will be recovered in the subsequent smelting process. For example, during the refining process, the titanium in the slag will react with the aluminum in the molten steel as follows: Lead to the increase of titanium in molten steel, resulting in unqualified final products

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