Method for smelting low phosphorus and sulfur steel with desulfurization and desiliconization of hot metal ladle and less converter slag

Abstract

The invention relates to a method for smelting a low phosphorus and sulfur steel with desulfurization and desiliconization of a hot metal ladle and less converter slag, belonging to the technical field of steel making. The method comprises the process steps: the hot metal pretreatment desulfurization is carried out in the hot metal ladle by KR method, and sulfur in the hot metal is removed to 0.002% or below in the hot metal ladle; the hot metal pretreatment desiliconization is carried out in the hot metal ladle by the KR method, and the silicon in the hot metal is removed to 0.20%-0.40%, at the end, the temperature of the hot metal is controlled to be 1250 DEG C or above and then the ladle is removed out; the low-silicon hot metal after desulfurization and desiliconization is put into a converter for decarburization, desiliconization and dephosphorization, and the low-silicon hot metal is exchanged into the converter for decarburization, desiliconization and dephosphorization, and thetop-bottom double-blowing process of top blowing oxygen and bottom blowing argon is used for smelting. At the end of smelting, the weight percentage of C in molten steel is 0.05% to 0.30%, and the end point [P]+[S] is smaller than or equal to 200ppm, the converter is subjected to tapping, the molten steel is discharged into a ladle directly for continuous casting or pouring after RH refining. Theadvantage is that compared with the prior art, the process flow is short, the total amount of phosphorus and sulfur at the end of the molten steel is low, and the total amount of slag is small.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and in particular relates to a method for desulfurizing and desiliconizing molten iron tanks and smelting low-phosphorus-sulfur steel with less slag in a converter, which can reduce the total content of phosphorus and sulfur in treated molten steel to below 0.020%. Background technique [0002] Generally, the traditional process of producing low-phosphorus-sulfur steel from molten steel is molten iron powder spraying desulfurization-converter smelting (dephosphorization)-LF (or RH). After the converter is tapped, the content of phosphorus + sulfur in molten steel is generally 0.030%. Above, the sulfur content is above 0.020%, which must be desulfurized by LF or RH refining to meet the low-sulfur steel standard with sulfur less than 0.005%. However, dephosphorization is carried out simultaneously with decarburization in conventional converters, and it is difficult to stably ensure that phospho...

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Problems solved by technology

[0018] The purpose of the present invention is to provide a method for desulfurization and desiliconization of molten iron tank and smelting low-phosphorus-sulfur steel with less slag in converter, which overcomes the problems of long processing period, large iron loss and high cost input due to complicated process

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