Method for producing low sulphur steel through carrying out CAS-OB refining on premelting calcium aluminate

Abstract

The invention provides a method for producing low sulphur steel through carrying out CAS-OB (Composition Adjustment by Sealed Argon Bubbling-Oxygen Bubbling) molten steel ladle refining on premelting calcium aluminate. The method mainly comprises the following steps: converter tapping, deep desulfurization in a CAS-OB refining furnace (argon stirring is carried out on molten steel during the whole process of refining desulfurization), drossing, refining, alloying treatment and continuous casting. Deep desulfurization is carried out by the method, so that the desulfurization rate can reach more than 85%, the sulfur content in the molten steel can be controlled below 0.002% stably, and the desulfurization efficiency is high and stable. Compared with the prior art, the method is simple to operate and stable in desulfurization effect, and does not influence the production rhythm. A used desulfurizer is aluminum-calcium premelting refining slag, is subjected to high-temperature melting treatment during the manufacturing process, has the characteristics of uniform compositions, low sulphur and low melting point, can achieve slugging quickly to desulfurize quickly, and reduces the environmental pollution.

Description

technical field [0001] The invention belongs to the field of metallurgy technology, and is used for removing sulfur in steel by applying premelted calcium aluminate in the refining process outside the furnace, especially applying premelted calcium aluminate in CAS-OB [CAS (Composition Adjustment by Sealed Argon Bubbling) means a liquid steel treatment device that seals argon blowing and stirring to adjust the composition, and OB means a method that can produce low-sulfur steel in the process of refining molten steel outside the refining furnace by blowing oxygen to raise the temperature. Background technique [0002] Sulfur is a harmful element in most steel types (except for free-cutting steel), and the inclusion of sulfide in steel will reduce the ductility and toughness of steel. Therefore, reducing the sulfur content in steel is very important to reduce the defects of steel and improve the mechanical properties of steel. Therefore, many steel types are required to reduc...

AI Technical Summary

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 molten steel tank lining refractory materials, but also cause pollution to the environment, the country has explicitly banned the use of Fluorspar is used in the steelmaking process