Novel low-phosphorus low-sulfur steel smelting process

Abstract

The invention provides a novel low-phosphorus low-sulfur steel smelting process. The novel low-phosphorus low-sulfur steel smelting process comprises the following steps: 1, carrying out furnace washing and steel ladle washing operations before converter smelting; 2, carrying out a desulfurization process, specifically, carrying out deep desulfurization by using high-temperature molten iron and adopting a KR desulfurization method, wherein the sulfur content in the molten iron is less than or equal to 0.001%; 3, carrying out a converter process, specifically, carrying out smelting by using a top-bottom combined blowing converter, adding self-produced first-class waste steel by adopting a single-slag remaining method, using low-phosphorus low-sulfur lime, dolomite and iron-containing oxide, carrying out converter end point control, specifically, controlling the tapping carbon content to be less than or equal to 0.04%, the phosphorus content to be less than or equal to 0.009%, the sulfur content to be less than or equal to 0.004% and the temperature to be greater than or equal to 1620 DEG C, adding a dephosphorization agent and lime in the tapping process for slag washing, adding part of lime for slag thickening treatment after tapping is finished, then carrying out slagging-off operation, and carrying out alloying after slagging-off is finished; 4, carrying out a refining process, specifically, carrying out fine adjustment on components, slagging, removing impurities and increasing the temperature; and 5, carrying out a continuous casting process, specifically, carrying out continuous casting, and finally ensuring that the content of phosphorus and sulfur in a casting blank smelting finished product is less than or equal to 100 ppm.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting, in particular to a new low-phosphorus and low-sulfur steel smelting process. Background technique [0002] As the market demand for high-grade high-quality steel is increasing, low-phosphorus-sulfur steel and ultra-low-phosphorus-sulfur steel, as an indispensable part of the pure steel production process, have received more and more attention. Reducing the content of phosphorus and sulfur in steel as much as possible has become the research direction of many iron and steel enterprises. [0003] Phosphorus and sulfur are long-standing elements in steel. Because they segregate at the grain boundaries of steel, they will affect the welding performance and resistance to sulfur stress-induced cracking of steel. Therefore, they are often regarded as harmful elements and need to be removed during smelting At present, in the smelting of low-phosphorus and low-sulfur steel, some advanced ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a new low-phosphorus and low-sulfur steel smelting process to solve the problems of low dephosphorization removal rate, unstable control of ultra-low phosphorus and sulfur stability, and high production costs in the existing iron and steel smelting process

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