Production method of low-sulfur steel

Abstract

The invention relates to the steelmaking technical field of the metallurgical industry, and in particular relates to a method for producing low-sulfur steel through the converter duplex technology. The production method comprises the following steps: (1) adding a desulfurizer in molten iron slagging iron slag to perform knotted reactor (KR) desulphurization treatment, skimming the desulfurized molten iron, and adding in a dephophorization furnace; (2) adding scrap steel and slag materials in the dephophorization furnace, blowing, and adding semisteel in a decarbonization furnace after the treatment; and (3) adding the slag materials in the decarbonization furnace, and blowing to ensure that S content in the molten steel is less than 0.005% after blowing. The method does not adopt low-frequency (LF) furnace refining to desulfurize; a converter can be directly used to stably produce the molten steel of which S content is less than 0.005%, thus better matching the production rhythm of continuous casting; for the production of the low-sulfur steel, S content is controlled to be less than 0.005% by the converter, thus the carburization and nitrogen increasing of molten steel caused by LF desulfurization can be avoided; and the total consumption amount of lime in the converter is less than 35kg / t and the total slag quantity is less than 70kg / t.

Description

technical field [0001] The invention relates to the technical field of steelmaking in the metallurgical industry, in particular to a method for producing low-sulfur steel using a double converter process. Background technique [0002] The existing converter sulfur control process, the converter sulfur distribution ratio is between 5 and 7, the amount of lime added is more than 70kg / t, and the amount of slag is more than 130kg / t, which cannot meet the requirements of producing low-sulfur steel with a sulfur content of less than 0.005%. [0003] For dual smelting with converters, the blowing time of the dephosphorization furnace is short, and the melting time of scrap steel is limited, so the requirements for scrap steel are very high, and it is easy to cause scrap steel not to melt and to return sulfur. For the decarburization furnace, the amount of slag is much smaller than that of the existing converter process, so the sulfur control effect is even worse, and a correspondin...

AI Technical Summary

Problems solved by technology

For the decarburization furnace, the amount of slag is much smaller than that of the existing converter process, so the sulfur control effect is even worse, and the corresponding desulfurization refining process after the converter is required

[0004] Due to the limited sulfur control capacity of the converter, in order to produce low-sulfur molten steel with S<0.005%, it is often necessary to carry out further desulfurization treatment through LF and RH in the subsequent process. The refining cost is high, the production rhythm is not well matched, and the quality of molten steel cannot meet the requirements.

Using RH powder spraying for desulfurization, due to the limited interface between slag and steel, it is not conducive to desulfurization, and the desulfurization effect is poor

The LF process adds a desulfurizer under the condition of electrode heating and bottom blowing and stirring, the desulfurization effect is good, and it can produce ultra-low sulfur steel; but the LF process is easy to cause the molten steel to increase carbon and nitrogen, which cannot meet the requirements of some steel types that require carbon and nitrogen. In addition, the molten steel treatment time of LF process is longer, and the matching between production rhythm and continuous casting is poor

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