Production method of low-sulfur low-phosphorus steel

Abstract

The invention discloses a production method of low-sulfur low-phosphorus steel. The production method adopts a double-converter process to perform dephosphorization and decarburization treatment on molten iron, and comprises the following steps that a desulfurizing agent is added into the molten iron, a mechanical stirring method desulfurization KR desulfurization treatment is carried out, and then slag removal and dephosphorization are carried out; then steel scraps and first slag material are added into a dephosphorization furnace to perform first blowing; after the first blowing, semisteelis added into a decarbonization furnace, then second slag material is added into the decarbonization furnace for second blowing, after the second blowing, S is less than or equal to 0.003%, and P is less than or equal to 0.006%; and then after the second blowing, steel slag is obtained and then washed for desulfurization and dephosphorization. According to the production method, double convertersare combined for smelting so that the nitrogen content of the molten iron can be reduced, cost of the steelmaking process is reduced, the low-sulfur low-phosphorus steel with s + p of less than or equal to 0.008% can be produced, cleanliness deterioration, the long smelting period and increased nitrogen of the molten iron caused by LF refining can be avoided, and meanwhile, matching of the continuous casting production rhythm is facilitated.

Description

technical field [0001] The present application relates to the technical field of iron and steel metallurgy, in particular to a method for producing low-sulfur and low-phosphorus steel. Background technique [0002] At present, in the conventional converter steelmaking process of domestic and foreign steel mills, the phosphorus content in molten steel is usually controlled at about 0.01%. However, due to the limited sulfur control ability of the converter itself, for the smelting of low-sulfur steel, converter + LF (ladle furnace, ladle refining is usually used) Method: A secondary refining process for molten steel, the main features are deep desulfurization and electrode heating) desulfurization process. However, in the current process, the converter uses a single converter, so LF is required for desulfurization, and the use of LF desulfurization will bring about the problem of nitrogen increase in molten steel, which is not suitable for smelting cold-rolled steel. Therefor...

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Problems solved by technology

However, in the current process, the converter uses a single converter, so LF is needed for desulfurization, and the use of LF desulfurization will bring about the problem of nitrogen increase in molten steel, which is not suitable for smelting cold-rolled steel.

Therefore, for the steel for low-phosphorus and low-sulfur cold-rolled welding wire that requires S+P≤0.008%, the existing steelmaking process is difficult to meet the demand

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