CN117363826A - Deoxidation process for converter smelting screw-thread steel - Google Patents

Deoxidation process for converter smelting screw-thread steel Download PDF

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Publication number
CN117363826A
CN117363826A CN202311337963.6A CN202311337963A CN117363826A CN 117363826 A CN117363826 A CN 117363826A CN 202311337963 A CN202311337963 A CN 202311337963A CN 117363826 A CN117363826 A CN 117363826A
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CN
China
Prior art keywords
steel
tapping
deoxidizing
deoxidization
screw
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202311337963.6A
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Chinese (zh)
Inventor
严明
傅余东
龙海山
刘学佳
冯川
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Yangchun New Iron and Steel Co Ltd
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Yangchun New Iron and Steel Co Ltd
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Publication date
Application filed by Yangchun New Iron and Steel Co Ltd filed Critical Yangchun New Iron and Steel Co Ltd
Priority to CN202311337963.6A priority Critical patent/CN117363826A/en
Publication of CN117363826A publication Critical patent/CN117363826A/en
Pending legal-status Critical Current

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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/0025Adding carbon material
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04Removing impurities by adding a treating agent
    • C21C7/06Deoxidising, e.g. killing
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Recycling

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)

Abstract

The invention discloses a process for deoxidizing screw-thread steel smelted by a converter, which comprises the steps of adding carbon powder under the condition of argon blowing to perform primary deoxidization before steel making of the converter reaches a final point; and during tapping, adding silicon carbide into molten steel for deoxidization, and finishing the addition within 120 seconds after tapping. The invention adopts carbon powder and silicon carbide to replace silicon-calcium-barium and silicon-aluminum-barium for deoxidizing molten steel. The carbon powder is pre-deoxidized, the silicon carbide contains silicon, and the deoxidizing capability is stronger than that of the carburant, so that the final deoxidization is performed. The carbon powder deoxidization product is CO gas, and most of the deoxidization products of silicon carbide are also CO gas, so that the sources of deoxidization inclusions can be reduced. When the screw steel is smelted in the converter, carbon powder is adopted for preliminary deoxidation under the argon blowing condition before tapping, and silicon carbide is adopted for final deoxidation of molten steel during tapping, so that the oxygen content before the molten steel is arranged on a continuous casting platform is less than 50ppm, the defects of subcutaneous bubbles, looseness and the like of a continuous casting blank are avoided, and the deoxidation cost is reduced.

Description

Deoxidation process for converter smelting screw-thread steel
Technical Field
The invention relates to a converter steelmaking process, in particular to a converter smelting screw-thread steel deoxidization process.
Background
The converter steelmaking is an oxidation process, when oxygen is blown to a terminal point, the carbon content in molten steel is continuously reduced, when the carbon content of the terminal point is reduced to below 0.15%, a large amount of oxygen is dissolved in the molten steel along with the further reduction of the carbon content of the molten steel, and excessive oxygen is separated out to form oxide inclusions and bubbles when the molten steel is solidified, so that the quality of casting blanks and steel products is directly influenced. Therefore, it is required to reduce the endpoint oxygen content of the converter and deoxidize the molten steel during the converter steelmaking process. In the prior art, the deoxidization process is to add the Si-Ca-Ba and Si-Al-Ba for deoxidization firstly during tapping and then add other alloys, and the deoxidization effect is better, but the cost is higher.
Disclosure of Invention
The invention aims to provide a deoxidation process for converter smelting screw steel.
Specifically, a process for deoxidizing screw-thread steel by converter smelting, wherein carbon powder is added under the condition of argon blowing to perform primary deoxidization before converter steelmaking reaches the end point; and during tapping, adding silicon carbide into molten steel for deoxidization, and finishing the addition within 120 seconds after tapping.
The invention adopts carbon powder and silicon carbide to replace silicon-calcium-barium and silicon-aluminum-barium for deoxidizing molten steel. The carbon powder is pre-deoxidized, the silicon carbide contains silicon, and the deoxidizing capability is stronger than that of the carburant, so that the final deoxidization is performed. The carbon powder deoxidization product is CO gas, and most of the deoxidization products of silicon carbide are also CO gas, so that the sources of deoxidization inclusions can be reduced.
The carbon content of the end point of converter steelmaking is controlled to be 0.04-0.15%.
The addition amount of carbon powder is 0.25-1 kg/ton steel.
The adding time of the silicon carbide is 20 seconds after tapping, the adding amount is 0.35-0.65 kg/ton of steel, and the adding amount is specifically adjusted according to the terminal carbon.
The silicon carbide needs to be added within 120 seconds after tapping.
After tapping for 30 seconds, adding a carburant for carbureting to the molten steel was started. And specifically, calculating the addition amount of the carburant according to the carbon of the finished product of the threaded steel, the carbon of the converter endpoint and the carburant of the silicon-manganese alloy.
The carburant needs to be added within 60 seconds after tapping.
After adding the carburant, adding ferrosilicon, ferromanganese, vanadium and nitrogen and other alloys into the molten steel, and adding all the alloys when tapping is performed by 3/4.
According to the invention, argon is blown in the whole tapping process, stirring of molten steel is enhanced, CO gas is promoted to be discharged, and potential safety hazards caused by splashing of CO gas caused by the covering of the molten steel are prevented.
The method provided by the invention has the following advantages:
when the screw steel is smelted in the converter, carbon powder is adopted for preliminary deoxidation under the argon blowing condition before tapping, and silicon carbide is adopted for final deoxidation of molten steel during tapping, so that the oxygen content before the molten steel is arranged on a continuous casting platform is less than 50ppm, the defects of subcutaneous bubbles, looseness and the like of a continuous casting blank are avoided, and the deoxidation cost is reduced.
The deoxidization cost of carbon powder and silicon carbide is 4.6 yuan/ton, the deoxidization cost of ton steel is reduced to 2.2 yuan/ton, and the annual effect reaches 660 yuan according to 300 ten thousand tons of steel plants producing screw steel per year. In the prior art, si-Ca-Ba and Si-Al-Ba are used for deoxidization, and the deoxidization cost of ton steel is 6.8 yuan/ton. Therefore, by using the deoxidizing process disclosed by the invention, the deoxidizing cost is reduced, and the economic benefit of enterprises is effectively improved.
Detailed Description
1. And (3) carrying out end point control on molten steel in the converter steelmaking process, controlling the end point carbon of the converter steelmaking to be 0.04% -0.15%, and stopping tapping when the end point carbon is more than 0.15%.
2. Pouring the steel water into a molten steel tank before tapping, entering an argon blowing station, adding carbon powder under the argon blowing condition, and performing primary deoxidation. Carbon powder contains 85% -90% of carbon. The carbon powder addition amount is 0.5 kg/ton of steel, and then the addition amount of a 120 ton converter is 60 kg/ton. The argon blowing pressure of the molten steel tank is 0.2-0.8Mpa. After adding carbon powder, the molten steel tank is opened and returned to the furnace for waiting.
3. After tapping for 20 seconds, adding silicon carbide into molten steel for deoxidization, wherein the adding amount is 0.35kg-0.65 kg/ton of steel, and the adding is completed within 120 seconds after tapping.
After tapping for 30 seconds, adding carburant for increasing molten steel carbon is started, and the charging is completed within 60 seconds after tapping. The adding amount of the carburant is controlled to be 0.21-0.25% according to the carbon of the threaded steel finished product, the end point carbon of the converter is controlled to be 0.04-0.15%, the carburant of the silicomanganese alloy is carburated to be 0.02-0.03%, and the carburant for carburating is calculated. The carburant contains 94% -97% of carbon.
And adding ferrosilicon, manganese, vanadium and nitrogen and other alloys into the molten steel, and finishing all the alloys when tapping is performed by 3/4.
Argon is blown in the whole tapping process, namely argon is blown in the whole tapping process from the beginning of tapping to the argon blowing station of molten steel, the argon blowing pressure is 0.2-0.8Mpa, the molten steel is stirred, CO is promoted to be discharged, and potential safety hazards caused by splashing of the molten steel are avoided. Tapping of the converter adopts slag blocking operation, and the slag discharging amount is controlled below 50 mm.
4. After tapping, the molten steel enters an argon blowing station, and then component adjustment is carried out, and the soft argon blowing time is longer than 2 minutes.
The method is used for treating the molten steel in multiple batches, and the oxygen content of the molten steel discharged from an argon blowing station is less than or equal to 49.8ppm. The continuous casting billet has no defects of subcutaneous air bubbles, looseness and the like, and the quality meets the national standard requirement.
Proved by verification, the carbon hit rate of molten steel entering an argon blowing station is 99.58 percent, and the carbon hit rate of molten steel exiting the argon blowing station is 99.92 percent, which is equivalent to the prior art.

Claims (9)

1. The process for deoxidizing the screw-thread steel during converter smelting is characterized in that carbon powder is added under the condition of argon blowing to perform primary deoxidization before converter steelmaking reaches the end point; and during tapping, adding silicon carbide into molten steel for deoxidization, and finishing the addition within 120 seconds after tapping.
2. The process for deoxidizing threaded steel for converter smelting according to claim 1, wherein the terminal carbon content of the converter steelmaking is controlled to be 0.04% -0.15%.
3. The process for deoxidizing screw-thread steel for converter smelting according to claim 1, wherein the carbon powder is added in an amount of 0.25-1 kg/ton of steel.
4. The process for deoxidizing the screw-thread steel for converter smelting according to claim 1, wherein the adding time of the silicon carbide is 0.35-0.65 kg/ton of steel after tapping for 20 seconds, and the adding amount is specifically adjusted according to the terminal carbon.
5. The process for deoxidizing a screw-thread steel for converter smelting according to claim 1 or 4, wherein the silicon carbide is added within 120 seconds of tapping.
6. The process for deoxidizing a screw-threaded steel for converter smelting according to claim 5, wherein the tapping is started for 30 seconds, and a carburant for carburetion is added to the molten steel.
7. The process for deoxidizing a screw-thread steel for converter smelting according to claim 6, wherein the carburant is added within 60 seconds of tapping.
8. The process for deoxidizing the screw-thread steel smelted by the converter according to claim 6, wherein after the carburant is added, alloys such as ferrosilicon, silicomanganese, vanadium and nitrogen are added into molten steel, and all the alloys are added when tapping is performed by 3/4.
9. The process according to claim 1, wherein argon is blown during the whole tapping process to stir the molten steel and to promote the discharge of CO gas.
CN202311337963.6A 2023-10-17 2023-10-17 Deoxidation process for converter smelting screw-thread steel Pending CN117363826A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311337963.6A CN117363826A (en) 2023-10-17 2023-10-17 Deoxidation process for converter smelting screw-thread steel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311337963.6A CN117363826A (en) 2023-10-17 2023-10-17 Deoxidation process for converter smelting screw-thread steel

Publications (1)

Publication Number Publication Date
CN117363826A true CN117363826A (en) 2024-01-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202311337963.6A Pending CN117363826A (en) 2023-10-17 2023-10-17 Deoxidation process for converter smelting screw-thread steel

Country Status (1)

Country Link
CN (1) CN117363826A (en)

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