Premelting compound refining slag for producing ultra-low sulfur steel

Abstract

The invention discloses premelting compound refining slag for producing ultra-low sulfur steel. A mixture is prepared from the following chemical constituents in percent by mass: 40 to 50 percent of CaO, 10 to 20 percent of MgCO3, 5 to 15 percent of CaF2, 2 to 10 percent of BaCO3, 15 to 25 percent of Al and 4 to 6 percent of CaSi, wherein the sum of the mass percent of the substances and unavoidable impurities is 100 percent, and a ratio of CaO to CaSi is between 8 and 11. The refining slag of the invention has good desulfuration effect and can reduce the S content in molten steel from 30 to 50*10<-6> to 10*10<-6>. The desulfuration effect is stable, the molten steel resulfurization and the molten steel recarburization and hydrogen increase do not exist, the corrosion of a furnace liner is light, the use is convenient, and the refining slag can be directly added onto the slag surface and can be also made into core wires to be fed into the molten steel.

Description

technical field [0001] The invention belongs to the technical field of refining deep desulfurization in steelmaking production, and particularly relates to steels requiring ultra-low sulfur content (S≤10×10 -6 ) for the production of special steel types such as high-grade pipeline steel above X65, and is also suitable for the production of ordinary low-sulfur steel types. Background technique [0002] Sulfur is known to be a detrimental element for most steel grades. It is very harmful to the quality of steel. It not only affects the hot workability, welding performance and corrosion resistance of steel, but also deteriorates the mechanical properties of steel. [0003] In order to eliminate the harmful effects of sulfur in steel, various steel mills at home and abroad have developed new ultra-low sulfur steel types with high added value. For this reason, metallurgists have developed various desulfurizers and desulfurization processes. International use of CaO-CaF 2 、CaO-...

AI Technical Summary

Problems solved by technology

When producing ultra-low sulfur steel, its common disadvantage is that the addition of about 20kg / t.s is too large, resulting in a large temperature drop of molten steel and high cost

[0006] Patent Publication No. CN1415765 discloses a new type of desulfurizer that can be used for desulfurization of molten iron or molten steel and its manufacturing process. The amount of binder used in this desulfurizer is large. If new ultra-low sulfur steel is produced, the molten steel will increase carbon and hydrogen.

[0007] If these composite desulfurizers are used in the production of ultra-low sulfur steel, there will be problems such as large dosage, large temperature drop of molten steel, and contamination of molten steel.

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