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Technological process for molten steel secondary refining dephosphorization to produce ultra-low phosphorus steel

A process method, a technology of refining outside the furnace, which is applied in the field of metallurgy, can solve problems such as complex procedures, complex processes, and reduced scrap steel, and achieve high dephosphorization efficiency, simple process, and favorable application effects

Active Publication Date: 2008-12-24
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For this reason, most of the current steel mills use the "double slag method", that is, two slagging in the converter smelting, or the "duplex method", that is, one converter is used to smelt molten iron for half the time and then pour it into another converter to continue smelting. method, the shortcomings 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; there is another way to carry out "three removals" on the molten iron in advance, that is, desiliconization, desulfurization, and dephosphorization, such as Japanese iron and steel companies , its disadvantage is that it requires a lot of equipment, large investment, complex process, large heat loss, and because the temperature of molten iron after "three removals" is low, the amount of scrap steel added during converter smelting is greatly reduced
Therefore, in order to produce these low-phosphorus and ultra-low-phosphorus steels, conventional converter smelting can no longer meet the phosphorus requirements of these steel types, so it is urgent to study the method of assisting dephosphorization by refining outside the furnace, so as to realize the production of ultra-low-phosphorus steel

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] The tapping temperature of the converter is controlled at 1550°C to 1660°C, and the phosphorus is controlled below 0.02% when tapping, and the tapping is treated with non-deoxidation and slag blocking; The addition amount is 5-20kg / t, and the addition is divided into two times. Add 1 / 3 of the dephosphorization flux when the tapping is halfway through, and add the remaining 2 / 3 of the dephosphorization flux when the tapping is about to end. The dephosphorization flux After the addition, the molten steel is blown and stirred with argon, the flow rate of argon is 50-220Nl / min, and the argon blowing time is 0.1-10min; Stop argon blowing and stirring, the feeding line speed is 180-350m / min, the feeding amount is 0.5-3.5kg / t, stand still for 0.1-10min after feeding the line, then blow argon for light treatment and stir, and the flow rate of argon gas is 50-3.5kg / t 280Nl / min, the weak argon blowing time is 0.1~5min; after the argon blowing and stirring, firstly use the vacuum ...

Embodiment 2

[0025] The tapping temperature of the converter is controlled at 1550°C to 1660°C, and the phosphorus is controlled below 0.02% when tapping, and the tapping is treated with non-deoxidation and slag blocking; The addition amount is 5-20kg / t, and the addition is divided into two times. Add 1 / 3 of the dephosphorization flux when the tapping is halfway through, and add the remaining 2 / 3 of the dephosphorization flux when the tapping is about to end. The dephosphorization flux After the addition, the molten steel is blown and stirred with argon, the flow rate of argon is 60-300Nl / min, and the time of argon blowing is 0.1-10min; Stop argon blowing and stirring, the feeding line speed is 180-350m / min, the feeding amount is 0.5-3.5kg / t, stand still for 0.1-10min after feeding the line, then blow argon for light treatment and stir, and the flow rate of argon gas is 50-3.5kg / t 280Nl / min, weak fluorine blowing time is 0.1~5min; after argon blowing and stirring, use vacuum slag suction m...

Embodiment 3

[0028]The tapping temperature of the converter is controlled at 1550°C to 1660°C, and the phosphorus is controlled below 0.02% when tapping, and the tapping is treated with non-deoxidation and slag blocking; The addition amount is 5-20kg / t, and the addition is divided into two times. Add 1 / 3 of the dephosphorization flux when the tapping is halfway through, and add the remaining 2 / 3 of the dephosphorization flux when the tapping is about to end. The dephosphorization flux After the addition, the molten steel is blown and stirred with argon, the flow rate of argon is 60-220Nl / min, and the argon blowing time is 0.1-10min; Stop argon blowing and stirring, the feeding line speed is 180-350m / min, the feeding amount is 0.5-3.5kg / t after feeding the line, stand still for 0.1-10min, and then blow argon for light treatment and stir, the flow rate of argon gas is 50-280Nl / min, the weak argon blowing time is 0.1~5min; after the argon blowing and stirring, first use the vacuum slag sucti...

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Abstract

The invention relates to a process for controlling phosphor in producing an ultra-low phosphorus steel by a microalloy steel, a high carbon steel and a special steel, in particular to a process method for producing the ultra-low phosphorus steel by refining and dephosphorization outside a molten steel furnace. The method comprises: (1) a step of tapping in a converter, during which, a tapping temperature is between 1550 and 1660 DEG C; a phosphor content is lower than 0.02 percent in tapping; and steel is tapped by adopting the treatment of non-deoxidization and slag stopping; (2) a step of primary dephosphorization, during which, a dephosphorization fusing agent is added into a steel ladle along the steel flow when the steel is tapped in the converter; and an adding amount of the dephosphorization fusing agent is between 5 and 20 kg / t; (3) a step of deep dephosphorization, during which, cored wire is fed to a steel liquid by adopting a wire feeding process; (4) a step of slag skimming: firstly, slag is skimmed; and secondly, a steel ladle covering agent is added; (5) a step of heating and stirring, during which, the steel liquid is heated and stirred in a refining furnace, and a heating temperature of the steel liquid is controlled to be between 1, 580 and 1, 620 DEG C; (6) the steel liquid is subjected to the treatment of deoxidization and alloying refining; and (7) a step of continuous casting: the continuous casting adopts whole-process protection, casting and rephosphoration control. The process method has high and stable dephosphorization efficiency and short dephosphorization time till the phosphor content is lower than 0.0030 percent.

Description

technical field [0001] The invention relates to a process for controlling phosphorus in ultra-low phosphorus steel produced by micro-alloy steel, high-carbon steel and special steel, especially a process method for producing ultra-low phosphorus steel by refining and dephosphorizing molten steel outside the furnace. The invention belongs to metallurgy technology field. Background technique [0002] It is well known that phosphorus is usually controlled as a harmful element in steel. Because the segregation of phosphorus in the steel is serious, the toughness of the steel is deteriorated, resulting in "cold brittleness", especially at low temperature conditions, it is more likely to occur "cold brittleness", and the segregation of phosphorus will also cause the anisotropy of the steel, reducing the Welding performance, causing corrosion fatigue of stainless steel. With the rapid development of science and technology, high-grade high-quality steel has continuously improved t...

Claims

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Application Information

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IPC IPC(8): C21C7/064
Inventor 唐复平王晓峰刘万山孟劲松任子平李德刚陈本文王仁贵张军王文仲李镇张晓军孙群栗红
Owner ANGANG STEEL CO LTD
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