Ladle refining deep desulphurization method for low-carbon aluminum killed steel

A technology for low-carbon aluminum killed steel and ladle refining, which is applied in the field of ladle refining and desulfurization and deep desulfurization in ladle refining.

Active Publication Date: 2012-06-27
INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, the method (CN101550513A) proposed by Shougang Corporation for the rapid and deep desulfurization of low-carbon steel aluminum deoxidized steel, though it can control the sulfur content of molten steel below 0.001%, has the following disadvantages: 1) the slag contains 3 ~5% CaF 2 , it is easy to cause corrosion of the ladle lining, which has adverse effects on the human body and the environment; 2) The CaO-based modifier used requires additional cost

Method used

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  • Ladle refining deep desulphurization method for low-carbon aluminum killed steel
  • Ladle refining deep desulphurization method for low-carbon aluminum killed steel

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Embodiment 1

[0020] Embodiment 1 The present embodiment adopts the technology of the present invention, and carries out experiment on X70 pipeline steel, and ladle is 180 tons, and it comprises following operation:

[0021] 1) Converter blowing end point [S]=0.0098%, [O]=687ppm. The slag is strictly prevented during the tapping of the converter. During the tapping process, 308kg of aluminum particles and 434kg of lime are added, and all the slag is added within 2 minutes before the end of tapping. Add 20kg of aluminum particles on the slag surface after tapping.

[0022] 2) When the ladle arrives at the station, take samples of slag and molten steel for analysis. When the ladle arrives at the station, [S]=0.0077% in molten steel, [Als]=0.0789% (see figure 1 2-6647 heat times), add lime 438kg, and energize the slag, and the molten steel temperature is 1568 ℃ when it arrives at the station for 5 minutes. During the refining process, the total flow rate of the ladle bottom blowing gas is c...

Embodiment 2

[0023] Embodiment 2 The present embodiment adopts the technology provided by the present invention to carry out experiments on X70 pipeline steel, and the ladle is 180 tons, which includes the following operations:

[0024] 1) Converter blowing end point [S] = 0.01%, [O] = 526ppm. The slag is strictly prevented during the tapping of the converter. During the tapping process, 330kg of aluminum particles and 430kg of lime are added, and all the slag is added within 2 minutes before the end of the tapping. Add 17kg of aluminum particles on the slag surface after tapping.

[0025] 2) When the ladle arrives at the station, take samples of slag and molten steel for analysis. When the ladle arrives at the station, [S]=0.00716% in molten steel, [Als]=0.0558% (see figure 1 3-7208 furnace times), add 350kg of lime, and electrify the slag, and the temperature of the molten steel at the station is 1541°C. During the refining process, the total flow rate of the ladle bottom blowing gas ...

Embodiment 3

[0026] Embodiment 3 The present embodiment adopts the technology provided by the present invention to carry out experiments on X70 pipeline steel, and the ladle is 180 tons, which includes the following operations:

[0027] 1) Converter blowing end point [S]=0.0073%, [O]=437ppm, temperature T=1619°C. The slag is strictly prevented during the tapping of the converter. During the tapping process, 273kg of aluminum particles and 430kg of lime are added, and all the slag is added within 2 minutes before the end of the tapping.

[0028] 2) When the ladle arrives at the station, take samples of slag and molten steel for analysis. When the ladle arrives at the station, [S]=0.0056% in molten steel, [Als]=0.0518% (see figure 13-7210 heats), add 250kg of lime, and electrify the slag, and the molten steel temperature is 1554°C when it arrives at the station for 5 minutes. During the refining process, the total flow rate of the ladle bottom blowing gas is controlled at 1.5-7NL / (min·t), ...

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Abstract

The invention discloses a ladle refining deep desulphurization method for low-carbon aluminum killed steel. The method comprises: adding 1.2-2.8kg / t of aluminum and 1-5kg / t of lime in a converter tapping process, finish adding all slag materials about 1-2min before the end of tapping, and adding 0-0.2kg / t of aluminum to the slag surface for rapid deoxidation of ladle top slag when the tapping is over; then, after the ladle arrives an LF (ladle furnace) refining station, adding 1-5kg / t of lime into the ladle, and conducting energizing for slag melting, in the refining process, controlling the total flow of bottom blowing gas of the ladle at 1-9NL / min.t and the content of acid-soluble aluminum in molten steel at 0,02-0.08wt%, and controlling the molten steel temperature at 1600-1640DEG C atthe terminal point of refining. Compared with prior art, the method of the invention needs no CaF2 that is unfavorable to human bodies and the environment, relatively expensive premelting slag and the like. And under the premise of not increasing the operation time, the sulfur content of the molten steel can be controlled below 0.001wt% within 40min, and the desulfurization rate can reach more than 80%. The method provided in the invention has the advantages of simple process, strong operability and low cost.

Description

technical field [0001] The invention relates to a ladle refining desulfurization process, in particular an economical and efficient ladle refining deep desulfurization method using only lime, which belongs to the technical field of steelmaking. Background technique [0002] Except for special steel types such as free-cutting steel, sulfur is a harmful element in steel. The sulfur element in the steel is easy to form low-melting sulfides at the grain boundaries during the solidification of molten steel, which makes the billet easy to form "hot embrittlement" during rolling, forging and welding. In addition, too high sulfur content in steel will produce more sulfide inclusions, which will significantly reduce the ductility, fatigue strength and other properties of steel. Especially for high-grade steels such as hydrogen-induced cracking (HIC) steel, the higher the sulfur content, the weaker the HIC corrosion resistance. With the increasing demand for high-quality steel, the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/064
CPCY02P10/20
Inventor 邹长东周彦召赵家七丁振涛皇祝平
Owner INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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