CN114657311A - Operation method for directly smelting variety steel by duplex semisteel - Google Patents

Operation method for directly smelting variety steel by duplex semisteel Download PDF

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Publication number
CN114657311A
CN114657311A CN202210413398.6A CN202210413398A CN114657311A CN 114657311 A CN114657311 A CN 114657311A CN 202210413398 A CN202210413398 A CN 202210413398A CN 114657311 A CN114657311 A CN 114657311A
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Prior art keywords
duplex
semisteel
steel
medium
content
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CN202210413398.6A
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Chinese (zh)
Inventor
韩雨亮
张永旺
陈刚
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Xinjiang Bayi Iron and Steel Co Ltd
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Xinjiang Bayi Iron and Steel Co Ltd
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Priority to CN202210413398.6A priority Critical patent/CN114657311A/en
Publication of CN114657311A publication Critical patent/CN114657311A/en
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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
    • C21C7/0006Adding metallic additives
    • 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
    • C21C7/0075Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
    • 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
    • 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
    • C21C2007/0093Duplex process; Two stage processes

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)

Abstract

The invention discloses an operation method for directly smelting variety steel by duplex semisteel, which aims at the defects of the traditional recarburization method of medium-high carbon steel, utilizes the advantages of the components and the temperature of molten iron after duplex, adopts the operation method for directly adding the molten iron after duplex into the molten steel of medium-high carbon steel, determines the used molten iron amount according to the contents of carbon, manganese, phosphorus and sulfur at the smelting end point of a converter, and only adds required silicon and manganese alloys in the deoxidation alloying process. After tapping, directly adding the duplex molten iron into a converter ladle of medium-high carbon steel, hoisting into a refining process for alloying fine adjustment and heating, so that the components, temperature and nitrogen content of the molten steel meet the requirements of steel grades, and then pouring by continuous casting.

Description

Operation method for directly smelting variety steel by duplex semisteel
Technical Field
The invention relates to an operation method for directly smelting variety steel by duplex semisteel.
Background
When smelting medium-high carbon steel grade in a converter, the control of the carbon content is generally carried out by adopting two modes of a 'one-time carbon drawing method' and an 'recarburization method'. The 'one-time carbon drawing method' is to draw carbon according to oxygen consumption and smelting time, and the carbon content and harmful elements of phosphorus and sulfur in the one-time converter meet the requirements of steel grades. However, the method requires high molten iron quality, has online limitation on harmful elements of phosphorus and sulfur, has low primary converter-reversing coincidence rate and needs secondary complementary blowing. The loss of final carbon is large during the blowing-in, so that the amount of gas dissolved in molten steel is increased, and the content of nitrogen is increased.
The "carburising" method is to smelt low carbon steel and then to carburise it according to the target value of carbon content by using carburant during tapping. Meanwhile, for medium-high carbon hard wire steel, strict requirements are placed on the nitrogen content of molten steel, and in the recarburization process, if the nitrogen content of a recarburization agent is high, the recarburization agent is added to bring impurities, the molten steel is polluted, the carbon absorption rate is unstable, the nitrogen content of the molten steel does not meet the control requirement of the molten steel component of a steel ladle of a converter, and the smelting difficulty of a refining process is increased.
After the Europe smelting furnace is put into production, because of adopting the smelting reduction iron-making technology, the furnace temperature is about 200 ℃ higher than the traditional blast furnace iron-making technology, Si in the furnace raw material is fully reduced, so that the silicon element in the molten iron is higher than the industry standard, the maximum [ Si ] in the molten iron is 10.5 percent, the minimum [ Si ] is 1.2 percent, and the average [ Si ] is 5.1 percent in the initial stage of furnace opening. The high-silicon molten iron is digested by a duplex smelting method aiming at the high-silicon molten iron in our factory, the carbon content of the molten iron through first duplex is 0.90-1.98%, the manganese content is 0.30-0.80%, the phosphorus content is 0.050-0.075%, and the sulfur content is 0.032-0.045%, the harmful elements in the components of the molten iron after duplex are reduced compared with those in the molten iron, and meanwhile, the temperature of the molten iron after duplex is 1400-1450 ℃ higher than that of the molten iron by about 200 ℃.
Disclosure of Invention
The invention aims to provide an operation method for directly smelting variety steel by duplex semisteel, which can meet the requirements of medium and high steel on the carbon, manganese, phosphorus and sulfur content specifications and the nitrogen content.
The technical scheme adopted by the invention is that the operation method for directly smelting the variety steel by the duplex semisteel comprises the following key point calculation processes:
1) the carbon content of the duplex semisteel is 0.90-1.98%, the addition amount of the carburant is replaced, and when the carbon content of the duplex semisteel is 1.44%, the carburant content of every 1 ton of duplex semisteel in 120 tons of medium-high carbon steel water is 0.012%;
2) the manganese content of the duplex semisteel is between 0.30 and 0.80 percent, the manganese content of the duplex semisteel is 0.0046 percent when the manganese content of the duplex semisteel is 0.55 percent and the manganese content of every 1 ton of the duplex semisteel is 0.0046 percent in 120 tons of medium-high carbon steel water;
3) the phosphorus content of the duplex semisteel is 0.050-0.075%, the phosphorus content of the duplex semisteel is higher than the technical requirement of the steel grade, the adding amount of the duplex semisteel is calculated according to the final phosphorus content of the medium-high carbon steel, and when the phosphorus content of the duplex semisteel is 0.0625%, the phosphorus increasing amount of every 1 ton of the duplex semisteel in 120 tons of medium-high carbon steel water is 0.0005%;
4) the sulfur content of the duplex semisteel is 0.032-0.045%, the sulfur content of the duplex semisteel is higher than the technical requirement of steel grade, the addition amount of the duplex semisteel is calculated according to the final sulfur content of the medium-high carbon steel, and when the phosphorus content of the duplex semisteel is 0.0385%, the sulfur increase amount of each 1 ton of the duplex semisteel in 120 tons of medium-high carbon steel water is 0.0003%;
5) the temperature of the duplex semisteel ladle is 1400-1450 ℃, the temperature of the duplex semisteel is lower than the required temperature of the medium-high carbon steel ladle and is more than 1500 ℃, and the temperature loss of the ladle is calculated according to the thermal balance; when the temperature of the duplex semisteel is 1425 ℃, cooling 5-7 ℃ in 120 tons of medium-high carbon steel water per 1 ton of duplex semisteel;
6) denitrogenation is carried out on duplex semisteel in a converter smelting link, the nitrogen content of the duplex semisteel is basically 12-20 ppm, and the nitrogen content of the duplex semisteel completely meets the requirement of the nitrogen content of steel according to the fact that the nitrogen content of a medium-high carbon steel end point in normal smelting of a converter is 35-40 ppm;
through the key point calculation process, the key limiting factor influencing the direct smelting of the variety steel by the duplex semisteel is determined to be the initial temperature of the steel ladle, the tonnage of the duplex semisteel directly added into the medium-high carbon steel ladle depends on the tapping end point temperature of the converter, and the calculation formula is as follows:
duplex semisteel charging amount x (5-7 ℃) = converter tapping temperature-tapping temperature drop-1500 DEG C
In the formula: the tapping temperature of the medium-high carbon steel converter is generally between 1610 ℃ and 1640 ℃; the tapping temperature of the medium-high carbon steel grade is reduced to 70-80 ℃; the tonnage of the duplex semi-steel directly blended into the steel ladle is controlled to be 4.2-8.5 tons through calculation, and the specific tonnage is calculated according to the actual temperature and blended into the steel ladle.
The operation steps of directly smelting the variety steel by the duplex semisteel are as follows:
1. installing independent metering, baking and heat insulating devices on the duplex semisteel travelling crane;
2. after the converter is deoxidized and alloyed, the ladle is opened to the iron adding position, and the calculated duplex semisteel is hoisted to the iron adding position by using a traveling crane for adding operation;
3. after the blending is finished, the steel car is driven to a refining station for refining, the components and the temperature of the molten steel are finely adjusted, the molten iron is directly blended into medium-high carbon steel for ladle smelting by utilizing the duplex steel, the energy consumption and the cost of a steelmaking process can be reduced, the steel yield is increased, and the labor intensity of workers is greatly reduced.
The invention has the following application range and application prospect:
1. the operation method for directly smelting variety steel by duplex semisteel is adopted, the process of remelting the semisteel after duplex is reduced, the material consumption of metal, slag, energy and the like in the secondary smelting process is reduced, the utilization rate of the duplex semisteel is greatly reduced, the molten steel yield of the converter is increased, and the cost of the steelmaking process is reduced by more than 10 yuan/t when 1 ton of the duplex semisteel is added.
2. The operation method for directly smelting the variety steel by using the duplex semisteel reduces the smelting frequency of the duplex semisteel and reduces the environmental protection accidents of slag overflow and splashing in the process of smelting the duplex semisteel by using the converter.
3. The operation method of directly smelting the variety steel by adopting the duplex semisteel has the advantages that the components of the duplex semisteel can be used for alloying carbon, silicon and manganese elements, so that the alloy is prevented from substituting into the source of inclusions in the deoxidation alloying process, and the number of foreign inclusions in the variety steel is reduced; meanwhile, the labor intensity of manual addition of the carburant and the alloy is reduced.
Detailed Description
An operation method for directly smelting variety steel by duplex semisteel,
aiming at the defects of the traditional recarburization method of medium-high carbon steel, the invention is carried out by utilizing the advantages of the components and the temperature of the molten iron after duplex, the operation method of directly adding the molten iron after duplex into the molten steel of medium-high carbon steel is adopted, the used molten iron amount is determined according to the contents of carbon, manganese, phosphorus and sulfur at the smelting end point of the converter, and only needed silicon and manganese alloys are added in the deoxidation alloying process. After tapping, directly adding the duplex molten iron into a converter ladle of medium-high carbon steel, hoisting into a refining process for alloying fine adjustment and heating, so that the components, temperature and nitrogen content of the molten steel meet the requirements of steel grades, and then pouring by continuous casting. The key point calculation process is as follows:
1. the carbon content of the duplex semisteel is 0.90-1.98%, so that the carbon can replace the addition amount of the carburant, and harmful elements brought in the process of adding the carburant are reduced; when the carbon content of the duplex semisteel is 1.44%, the carburetion amount of each 1 ton of duplex semisteel in 120 tons of medium-high carbon steel water is 0.012%.
2. The manganese content of the duplex semisteel is between 0.30 and 0.80 percent, and the manganese-containing duplex semisteel can replace part of manganese alloy, so that the temperature drop of a steel ladle in the alloy adding process is reduced; when the manganese content of the duplex semisteel is 0.55%, the manganese increasing amount of each 1 ton of duplex semisteel in 120 tons of medium-high carbon steel water is 0.0046%.
3. The phosphorus content of the duplex semisteel is 0.050-0.075%, the phosphorus content of the duplex semisteel is higher than the technical requirement of steel grade, the adding amount of the duplex semisteel is calculated according to the final phosphorus content of medium-high carbon steel, and the phosphorus element is prevented from exceeding the national standard requirement; when the phosphorus content of the duplex semisteel is 0.0625%, the phosphorus increasing amount of each 1 ton of duplex semisteel in 120 tons of medium-high carbon steel water is 0.0005%.
4. The sulfur content of the duplex semisteel is 0.032-0.045%, the sulfur content of the duplex semisteel is higher than the technical requirement of steel grade, the adding amount of the duplex semisteel is calculated according to the final sulfur content of medium-high carbon steel, and the sulfur element is prevented from exceeding the national standard requirement; when the phosphorus content of the duplex semisteel is 0.0385%, the sulfur increase of every 1 ton of duplex semisteel in 120 tons of medium-high carbon steel water is 0.0003%.
5. The temperature of the duplex semi-steel ladle is 1400-1450 ℃, the temperature of the duplex semi-steel is lower than the required temperature of the medium-high carbon steel ladle and is more than 1500 ℃ (the liquidus temperature is 1485 ℃), and the temperature loss of the ladle is calculated according to the heat balance; and (3) cooling the duplex semisteel by about 5-7 ℃ in 120 tons of medium-carbon steel water when the temperature of the duplex semisteel is 1425 ℃.
6. The duplex semisteel is denitrified in the converter smelting link, the nitrogen content of the duplex semisteel is basically 12-20 ppm, and the nitrogen content of the duplex semisteel completely meets the requirement of the nitrogen content of steel types according to the fact that the nitrogen content of the medium-high carbon steel terminal point in normal smelting of the converter is 35-40 ppm.
Through the key point calculation process, the key limiting factor influencing the direct smelting of variety steel of duplex semisteel is determined to be the initial temperature of the steel ladle. The tonnage of directly adding duplex semisteel into a medium-high carbon steel ladle depends on the tapping end point temperature of the converter, and the calculation formula is as follows:
duplex semisteel charging amount x (5-7 ℃) = converter tapping temperature-tapping temperature drop-1500 DEG C
In the formula:
the tapping temperature of the medium-high carbon steel converter is generally between 1610 ℃ and 1640 ℃;
the temperature drop of the medium-high carbon steel grade tapping is generally between 70 and 80 ℃.
And calculating to obtain that the tonnage of the duplex semi-steel directly added into the steel ladle is controlled to be 4.2-8.5 tons, and the specific tonnage is calculated according to the actual temperature and added into the steel ladle.
The operation steps of directly smelting the variety steel by the duplex semisteel are as follows:
1. and independent metering, baking and heat insulating devices are arranged on the duplex semi-steel travelling crane. The requirement of the temperature of the duplex half-ladle is met.
2. And after the converter is deoxidized and alloyed, opening the steel ladle to a hot metal adding position, and hoisting the calculated duplex semisteel to the hot metal adding position by using a traveling crane for adding operation.
3. After the blending is finished, the steel car is driven to a refining station for refining, and the components and the temperature of the molten steel are finely adjusted. The hot metal after duplex smelting is directly added into the steel ladle to smelt medium-high carbon steel, so that the energy consumption and cost of the steelmaking process can be reduced, the steel yield is increased, and the labor intensity of workers is greatly reduced.

Claims (1)

1. An operation method for directly smelting variety steel by duplex semisteel is characterized in that the calculation process of key points is as follows:
1) the carbon content of the duplex semisteel is 0.90-1.98%, the addition amount of the carburant is replaced, and when the carbon content of the duplex semisteel is 1.44%, the carburant content of every 1 ton of duplex semisteel in 120 tons of medium-high carbon steel water is 0.012%;
2) the manganese content of the duplex semisteel is between 0.30 and 0.80 percent, the manganese content of the duplex semisteel is 0.0046 percent when the manganese content of the duplex semisteel is 0.55 percent and the manganese content of every 1 ton of the duplex semisteel is 0.0046 percent in 120 tons of medium-high carbon steel water;
3) the phosphorus content of the duplex semisteel is 0.050-0.075%, the phosphorus content of the duplex semisteel is higher than the technical requirement of the steel grade, the adding amount of the duplex semisteel is calculated according to the final phosphorus content of the medium-high carbon steel, and when the phosphorus content of the duplex semisteel is 0.0625%, the phosphorus increasing amount of every 1 ton of the duplex semisteel in 120 tons of medium-high carbon steel water is 0.0005%;
4) the sulfur content of the duplex semisteel is between 0.032 and 0.045 percent, the sulfur content of the duplex semisteel is higher than the technical requirement of steel grade, the adding amount of the duplex semisteel is calculated according to the final sulfur content of medium-high carbon steel, and when the phosphorus content of the duplex semisteel is 0.0385 percent, the sulfur increasing amount of every 1 ton of the duplex semisteel in 120 tons of medium-high carbon steel water is 0.0003 percent;
5) the temperature of the duplex semisteel ladle is 1400-1450 ℃, the temperature of the duplex semisteel is lower than the required temperature of the medium-high carbon steel ladle and is more than 1500 ℃, and the temperature loss of the ladle is calculated according to the thermal balance; cooling the duplex semi-steel by 5-7 ℃ in 120 tons of medium-carbon steel water when the temperature of the duplex semi-steel is 1425 ℃;
6) denitrogenating duplex semisteel in a converter smelting link, wherein the nitrogen content of the duplex semisteel is basically 12-20 ppm, and the nitrogen content of the duplex semisteel completely meets the nitrogen content requirement of steel grades according to the nitrogen content of a medium-high carbon steel end point in normal smelting of the converter being 35-40 ppm;
7) determining the key limiting factor influencing the direct smelting of the variety steel by the duplex semisteel as the initial temperature of the ladle through the key point calculation process, wherein the tonnage of the duplex semisteel directly added into the medium-high carbon ladle depends on the tapping end point temperature of the converter, and the calculation formula is as follows:
the duplex semisteel iron adding amount is multiplied by 5-7 ℃, namely, the tapping temperature of the converter is decreased to-1500 ℃;
in the formula: the tapping temperature of the medium-high carbon steel converter is generally between 1610 ℃ and 1640 ℃; the tapping temperature of the medium-high carbon steel grade is reduced to 70-80 ℃; and calculating to obtain that the tonnage of the duplex semi-steel directly added into the steel ladle is controlled to be 4.2-8.5 tons, and the specific tonnage is calculated according to the actual temperature and added into the steel ladle.
CN202210413398.6A 2022-04-20 2022-04-20 Operation method for directly smelting variety steel by duplex semisteel Pending CN114657311A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115418430A (en) * 2022-07-17 2022-12-02 新疆八一钢铁股份有限公司 Operation method for duplex smelting of steel ladle cold steel

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Publication number Priority date Publication date Assignee Title
JP2002012912A (en) * 2000-06-30 2002-01-15 Kawasaki Steel Corp Method for producing high-carbon/low-nitrogen steel
CN102994871A (en) * 2012-11-22 2013-03-27 河北钢铁股份有限公司承德分公司 Method for smelting medium/high-carbon hard-wired steel by vanadium-titanium containing molten iron
CN103627840A (en) * 2013-11-14 2014-03-12 攀钢集团研究院有限公司 Method for enhancing end point carbon content of converter and semisteel steelmaking method
CN106244765A (en) * 2016-09-05 2016-12-21 攀钢集团攀枝花钢铁研究院有限公司 The denitrogenation method of converter semi-steel making
CN111378807A (en) * 2018-12-31 2020-07-07 新疆八一钢铁股份有限公司 Method for applying molten iron as alloy material to converter steelmaking

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002012912A (en) * 2000-06-30 2002-01-15 Kawasaki Steel Corp Method for producing high-carbon/low-nitrogen steel
CN102994871A (en) * 2012-11-22 2013-03-27 河北钢铁股份有限公司承德分公司 Method for smelting medium/high-carbon hard-wired steel by vanadium-titanium containing molten iron
CN103627840A (en) * 2013-11-14 2014-03-12 攀钢集团研究院有限公司 Method for enhancing end point carbon content of converter and semisteel steelmaking method
CN106244765A (en) * 2016-09-05 2016-12-21 攀钢集团攀枝花钢铁研究院有限公司 The denitrogenation method of converter semi-steel making
CN111378807A (en) * 2018-12-31 2020-07-07 新疆八一钢铁股份有限公司 Method for applying molten iron as alloy material to converter steelmaking

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115418430A (en) * 2022-07-17 2022-12-02 新疆八一钢铁股份有限公司 Operation method for duplex smelting of steel ladle cold steel
CN115418430B (en) * 2022-07-17 2023-07-28 新疆八一钢铁股份有限公司 Operation method for duplex smelting ladle cold steel

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Application publication date: 20220624