Method for controlling aluminum component in steel

Abstract

The invention belongs to the technical field of ferrous metallurgy and relates to a method for controlling an aluminum component in steel. In order to solve technical problems, the invention provides the method for precisely and stably controlling the aluminum component in steel, particularly the aluminum component in low-carbon aluminium steel. The control method comprises the following steps of: A, smelting in an electric furnace or a converter, wherein the primarily smelted molten steel is deoxidized by aluminum after the molten steel is discharged; B, low-frequency (LF) refining; and C, continuous casting. The control method is characterized in that: in the LF refining process, the adding amount of slag is 12 to 14Kg per ton of steel during slagging; and based on 100 weight parts, the slag mainly comprises the following components in part by weight: 60 to 68 parts of CaO, 15 to 20 parts of Al203, more than zero part and less than or equal to 5.0 parts of SiO2, more than zero part and less than or equal to 3.0 parts of MgO and 10 to 15 parts of CaF2. When the control method is used, the activity of SiO2 in the slag can be reduced, and the probability of reaction between aluminum in the steel and SiO2 in the slag can be reduced, so that the aluminum component in the molten steel is precisely controlled and the desulfurization rate of the molten slag is also improved at the same time.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and relates to a method for controlling aluminum components in steel. Background technique [0002] In recent years, with the development of my country's petroleum, nuclear power and other industries, users' demand for low-carbon aluminum steel is increasing. Low-carbon steel contains an appropriate amount of aluminum (requires Al in steel total Content 0.020~0.050%), can refine the grain of steel, improve the strength and low temperature impact performance of steel. However, due to the very active chemical properties of aluminum, it is easy to react with oxygen in the steel and air during the smelting process, and it is also easy to react with SiO in the slag. 2 , FeO, MnO and other unstable oxide reactions, if there is 2 / 3[Al]+1 / 2(SiO 2 )=1 / 3(Al 2 o 3 )+1 / 2[Si] and other reactions, resulting in extremely unstable aluminum yield. [0003] In order to meet the high quality...

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Problems solved by technology

[0004] Chinese patent (application number 03113293.6) discloses a "production process of aluminum-containing steel grades", which adopts electric furnace, LF furnace refining and continuous casting process to produce steel grades with aluminum content ≥ 0.020%, but without vacuum treatment during production , and there is no report on the control method of aluminum composition

[0007] In the past, the inventor used electric furnace or converter smelting-LF-vacuum treatment-continuous casting process to produce low-carbon aluminum content steel, wherein the steel was deoxidized by SiAlBaCa (Si content 50-60%), after LF+vacuum treatment, at the LF station, the slag The basicity is controlled by 3~5, the SiO in the slag 2 The content is 10-20% high, the number of supplementary aluminum wires is 2-4 times, and the aluminum composition in the steel is controlled only by experience, but after vacuum treatment, coupled with the full reaction between the steel slag, resulting in the SiO in aluminum reduction slag 2 The amount of silicon increase reaches 0.05-0.09%, and the loss of aluminum is relatively large. A little carelessness will lead to excessive aluminum and silicon components

The qualified rate of aluminum composition control is only 80-85%