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Method for producing ultra-low phosphorus steel through applying pre-melting calcium ferrite to refine outside LF (Ladle Furnace) molten steel furnace

A technology for out-of-furnace refining, ultra-low phosphorus steel, applied in the field of metallurgy, can solve the problems of insufficient production of converters, reduction of scrap steel, long smelting time, etc., achieve stable dephosphorization efficiency, reduce oxygen consumption, and reduce smelting the effect of strength

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 1580°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 LF refining station, and the molten steel is blown and stirred with argon. The flow rate of argon is controlled at 50NL / min. The pre-melted calcium ferrite is added to the molten steel at one time from the silo, and the amount of pre-melted calcium ferrite is controlled. For 5Kg / ton 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 taken out of the LF refining station; the ladle is transported to the slag removal station, and the The slag removal machine removes the molten slag on the surface of the mol...

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 LF refining station, and the molten steel is blown and stirred with argon. The flow rate of argon is controlled at 100NL / min. The pre-melted calcium ferrite is added to the molten steel at one time from the silo, and the amount of pre-melted calcium ferrite is controlled. For 8Kg / ton steel, the particle size is controlled at 0.1mm-100mm, and the refining treatment time is controlled at 9-12min. After the refining treatment, the argon stirring is stopped, and the ladle is opened out of the LF refining station; the ladle is transported to the slag removal station, and the The slag removal machine removes the molten slag on the surface of the mo...

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 LF refining station, and the molten steel is blown and stirred with argon. The flow rate of argon is controlled at 180NL / min. The pre-melted calcium ferrite is added to the molten steel at one time from the silo, and the amount of pre-melted calcium ferrite is controlled. For 10Kg / ton of steel, the particle size is controlled at 0.1mm-100mm, and the refining treatment time is controlled at 7-9min. After the refining treatment, the argon stirring is stopped, and the ladle is opened out of the LF refining station; the ladle is transported to the slag removal station, and the The slag removal machine removes the molten slag on the surface of the ...

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Abstract

The invention provides a method for producing ultra-low phosphorus steel through applying pre-melting calcium ferrite to refine outside an LF (ladle furnace) molten steel furnace. The method mainly the following steps: tapping through a converter, deeply removing phosphorus through an LF refining furnace (carrying out argon stirring on molten steel in the whole refining and phosphorus removal process), drossing, adjusting temperature and stirring, deoxidizing, refining, alloying and continuously casting. Deep phosphorus removal is carried out through the method, so that the phosphorus removal rate is more than 80%, the phosphorus content in the molten steel is lower than 0.003%, the phosphorus removal efficiency is high and stable, the smelting intensity of the converter is reduced, the service life of the converter is increased, and meanwhile, the lime consumption and the oxygen consumption are reduced, the electric energy is saved, the consumption of a steel material is reduced, and the metal yield is improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and is used for removing phosphorus in steel by using pre-melted calcium ferrite in the refining process outside the furnace, especially applying pre-melted calcium ferrite in LF refining furnace (Ladle Furnace ladle refining furnace) The invention discloses a method for producing ultra-low phosphorus steel in the process of refining molten steel outside the furnace. 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 welding performance, and cause corrosion fatigue of stainless steel, so it must be strictly controlled. In traditional technology, the phosphorus in steel i...

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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