Method of refining and desulfurizing for low-silicon steel

Abstract

The invention discloses a method of refining and desulfurizing for low-silicon steel. The method includes the steps of adjustment of a slag system, slagging, heating and desulfurizing; the to-be-refined low-silicon steel comprises the components of less than or equal to 0.03% of Si and 0.020-0.030% of S. Aluminum powder is added in a steel ladle to regulate the slag system to reduce oxidability ofslag firstly, and then lime and fluorite are added to perform slagging. Calcium carbides are added when liquid steel is heated to a temperature of more than 1600 DEG C, the weak reducibility of the calcium carbides are used for removing oxygen of the refined slag to further accelerate desulfurization, and achieving the purpose of reducing sulphur content in the liquid steel. The reducibility of the calcium carbides is weak and cannot restore silicon in the slag, so that the increasing of the silicon content in the liquid steel can be avoided, oxidative product of the calcium carbides is carbon monoxide, and the submerged arc effect in the refining process can be improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for refining and desulfurizing low-silicon steel. Background technique [0002] Sulfur is easy to cause hot embrittlement of steel, so it is a harmful element in most steel. In the actual production process, due to the limited desulfurization efficiency of the converter blowing process, generally 40-60%, when the sulfur content in molten iron is high, the sulfur content in molten steel entering refining will also be high (0.020%≤S≤0.030%) . High temperature, high alkalinity, large amount of slag and low oxidation are favorable conditions for desulfurization. In the refining process, in order to remove sulfur from molten steel, the oxidation of steel slag must be reduced first. However, in the refining process of low-silicon steel, if a strong deoxidizer is completely used for deoxidation, it is easy to cause the molten steel to return to silicon, and the...

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Problems solved by technology

However, in the refining process of low silicon steel, if a strong deoxidizer is completely used for deoxidation, it is easy to cause molten steel to return to silicon, and the silicon content of molten steel exceeds the standard, resulting in the cast slab becoming a waste product

[0003] The 120-ton converter system of Hesteel and Chenggang adopts the dual process of vanadium-containing molten iron to produce low-silicon steel. After the vanadium-containing molten iron is treated with vanadium extraction, the carbon content of the semi-steel is low and the silicon content is less than 0.10%, which makes it difficult to slag in the converter smelting process. , the desulfurization rate is low, resulting in high sulfur content in molten steel entering refining

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