Method for producing ultralow phosphoretic steel through carrying out CAS-OB molten steel ladle refining on premelting calcium ferrite

An extra-furnace refining and ultra-low phosphorus steel technology, which is applied in the metallurgical field, can solve the problems of insufficient utilization of converter productivity, reduction of scrap steel, long smelting time, etc., achieve dephosphorization efficiency and stability, reduce oxygen consumption, and reduce smelting The effect of intensity

Inactive Publication Date: 2013-01-16
LIAONING TIANHE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, most steel mills adopt the "double slag method", that is, two slag making methods are used in the converter smelting; or the "duplex method", that is, the molten iron is smelted in one converter for half the time and then poured into another converter to continue smelting. The disadvantages of these two methods are that the process is complex, the smelting time is long, and the productivity of the converter cannot be fully utilized.
Another way is to carry out "three removals" on molten iron in advance, that is, desiliconization, desulfurization, and dephosphorization. For example, Japanese iron and steel enterprises have the disadvantages of requiring more equipment, large investment, complicated process, and large heat loss. The temperature of molten iron after "three removals" is low, which greatly reduces the amount of steel scrap added during converter smelting
Therefore, in order to produce these low-phosphorus and ultra-low-phosphorus steels, conventional converter smelting methods can no longer meet the phosphorus requirements of these steel types, so it is necessary to study the method of assisting dephosphorization by refining outside the furnace, so as to realize the production of ultra-low phosphorus steels

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] After the converter smelting is completed, the phosphorus content at the end of the converter is controlled below 0.03%, the tapping temperature is controlled at about 1590°C, the molten steel is not deoxidized during the tapping process, and slag blocking treatment is used during the tapping process; The ladle is transported to the CAS-OB refining station, and the molten steel is blown and stirred with argon. The flow rate of argon is controlled at 50NL / min, and the pre-melted calcium ferrite is added to the molten steel at one time from the silo. The dosage is controlled at 5Kg / ton of steel, the particle size is controlled at 0.1mm-100mm, and the refining treatment time is controlled at 12-15min. After the refining treatment, the argon stirring is stopped, and the ladle is opened out of the CAS-OB refining station; the ladle is transported to slag removal At the station, use the slag remover to remove the slag on the surface of the molten steel after dephosphorization,...

Embodiment 2

[0035]After the converter smelting is completed, the phosphorus content at the end of the converter is controlled below 0.03%, the tapping temperature is controlled at about 1620°C, the molten steel is not deoxidized during the tapping process, and slag blocking treatment is used during the tapping process; The ladle is transported to the CAS-OB refining station, and the molten steel is blown and stirred with argon. The flow rate of the argon gas is controlled at 100NL / min. The dosage is controlled at 8Kg / ton of steel, the particle size is controlled at 0.1mm-100mm, the refining treatment time is controlled at 9-12min, and the argon gas stirring is stopped after the refining treatment is completed, and the ladle is taken out of the CAS-OB refining station; the ladle is transported to the slag removal station At the station, use the slag remover to remove the slag on the surface of the molten steel after dephosphorization treatment, and then add a ladle covering agent of 4Kg / ton...

Embodiment 3

[0037] After the converter smelting is completed, the phosphorus content at the end of the converter is controlled below 0.03%, the tapping temperature is controlled at about 1650°C, the molten steel is not deoxidized during the tapping process, and slag blocking treatment is used during the tapping process; The ladle is transported to the CAS-OB refining station, and the molten steel is blown and stirred with argon. The flow rate of the argon gas is controlled at 180NL / min. The dosage is controlled at 10Kg / ton of steel, the particle size is controlled at 0.1mm-100mm, and the refining treatment time is controlled at 7-9 minutes. After the refining treatment, the argon stirring is stopped, and the ladle is opened out of the CAS-OB refining station; the ladle is transported to the slag removal station. At the station, use the slag removal machine to remove the slag on the surface of the molten steel after dephosphorization treatment, and then add a ladle covering agent of 5Kg / ton...

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Abstract

The invention provides a method for producing ultralow phosphoretic steel through carrying out CAS-OB (Composition Adjustment by Sealed Argon Bubbling-Oxygen Bubbling) molten steel ladle refining on premelting calcium ferrite. The method mainly comprises the following steps: converter tapping, deep dephosphorization in a CAS-OB refining furnace (argon stirring is carried out on molten steel during the whole process of refining dephosphorization), drossing, temperature regulation and stirring, deoxidation, refining, alloying treatment and continuous casting. Deep dephosphorization is carried out by the method, so that the dephosphorization rate can reach more than 80%, the phosphorus content in the molten steel can be controlled below 0.003% stably, the dephosphorization efficiency is high and stable, the melting strength of a converter is reduced, and the service life of the converter is prolonged; and meanwhile, lime consumption and oxygen consumption can be reduced, electric energy can be saved, steel consumption is reduced, and the metal yield is increased.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and is used for removing phosphorus in steel by applying premelted calcium ferrite in the refining process outside the furnace, especially applying premelted calcium ferrite 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 ultra-low phosphorus steel during the external refining process of molten steel in a refining furnace that can be heated by oxygen blowing. Background technique [0002] Phosphorus is usually a harmful element in steel, because the segregation of phosphorus in steel is relatively serious, which deteriorates the toughness of steel and produces "cold brittleness", especially at low temperature conditions, it is more likely to occur "cold brittleness". Phosphorus segregation can also cause anisotropy of steel, reduce weldi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/064
CPCY02P40/40
Inventor 陈云天
Owner LIAONING TIANHE TECH
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