Method for producing high-quality low-sulfur steel by using aluminium and calcium premelted refining slag

Abstract

The invention puts forward a method for producing high-quality low-sulfur steel by using aluminium and calcium premelted refining slag, and the method can remove the sulfur in molten steel to be less than 0.0010 % and realize the goal of production of the high-quality low-sulfur steel. The method comprises using the aluminium and calcium premelted refining slag rich in calcium oxide and alumina during the producing process, the components range of the refining slag being 40 to 60 % CaO, 40 to 60 % of Al2O3, not more than 8 % of SiO2, and not more than 2 % of F<->, and the granularity being 5 to 35 mm; respectively adding one third of the refining slag before tapping, before refining and in the refining, with the adding amount being 5 to 10 kg / t steel; blowing argon gas from the bottom and stirring during the whole process of refining, with the stirring intensity not making the molten steel expose; and continuing to lightly blow the argon gas for the molten steel for 5 minutes after refining. The method is simple to operate and stable in desulphurization effect, and does not influence production rhythm. The refining slag used in the invention has characteristics of uniform components, low fluorine and low melting point due to a high-temperature melting processing during a manufacturing process thereof, and can realize quick slagging, achieve the goal of rapid desulphurization and reduce pollution to the environment.

Description

technical field [0001] The invention relates to the technical field of iron and steel metallurgy and steelmaking production technology, in particular to a method for producing high-quality low-sulfur steel by using aluminum-calcium premelting type refining slag in out-of-furnace refining. Background technique [0002] Sulfur is a harmful element in most steel grades (except free-cutting steel), and the inclusion of sulfide in steel will reduce the ductility and toughness of the steel. Therefore, reducing the sulfur content in the steel is very important to reduce the defects of the steel and improve the mechanical properties of the steel. Therefore, many steel grades are required to reduce the sulfur content as low as possible. Through literature search, "E.T.Turkdogan Fundamentals of Steelmaking" mentioned that V-KIP ​​(Vacuum-Kimizu Injeet Procass, namely vacuum-Kimizu injection treatment ladle refining method) of Kimitsu Steel Works in Japan can remove sulfur to 0.0002% ...

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Problems solved by technology

Through literature search, "E.T.Turkdogan Fundamentals of Steelmaking" mentioned that Japanese Kimizu Iron and Steel Works V-KIP ​​(Vacuum-Kimizu Injeet Procass, that is, vacuum-Kimizu jet treatment ladle refining method) can remove sulfur to 0.0002% ~ 0.0005%, in all Among the refining equipment, V-KIP ​​has the largest stirring energy and the strongest desulfurization ability, but there is no such equipment in China

Chinese patent 200610047101.X is a deep desulfurizer for ultra-low carbon steel refining and its manufacturing method. It is mentioned in the revised literature that its desulfurization effect is better, but through theoretical material balance calculations, its aluminum content is not enough to reduce steel slag. oxides in

Therefore, it is impossible to complete deep desulfurization; and the desulfurization process is too complicated, and the feeding is divided into 5 to 15 times, and the temperature detection is required each time. The process operation becomes difficult, and the multiple temperature measurement also indirectly increases the cost.

In addition, the desulfurizer also contains 1% to 3% fluorite. At present, because it will not only affect the service life of the furnace body or the molten steel tank lining refractory, but also cause pollution to the environment, the country has explicitly banned the use of Fluorspar is used in the steelmaking process

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