CN117467884A - Control method for reducing nitrogen content of molten steel in converter in low iron loss mode - Google Patents
Control method for reducing nitrogen content of molten steel in converter in low iron loss mode Download PDFInfo
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- CN117467884A CN117467884A CN202311193862.6A CN202311193862A CN117467884A CN 117467884 A CN117467884 A CN 117467884A CN 202311193862 A CN202311193862 A CN 202311193862A CN 117467884 A CN117467884 A CN 117467884A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 112
- 239000010959 steel Substances 0.000 title claims abstract description 112
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 title claims abstract description 108
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 70
- 229910052757 nitrogen Inorganic materials 0.000 title claims abstract description 56
- 238000000034 method Methods 0.000 title claims abstract description 44
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 35
- 238000007664 blowing Methods 0.000 claims abstract description 41
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 26
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 19
- 239000001301 oxygen Substances 0.000 claims abstract description 19
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 19
- 239000002893 slag Substances 0.000 claims abstract description 18
- 230000008569 process Effects 0.000 claims abstract description 17
- 238000010079 rubber tapping Methods 0.000 claims abstract description 16
- 229910052786 argon Inorganic materials 0.000 claims abstract description 13
- 238000005275 alloying Methods 0.000 claims abstract description 8
- 238000003756 stirring Methods 0.000 claims abstract description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 5
- PWKWDCOTNGQLID-UHFFFAOYSA-N [N].[Ar] Chemical compound [N].[Ar] PWKWDCOTNGQLID-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000003607 modifier Substances 0.000 claims abstract description 5
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 5
- 239000010703 silicon Substances 0.000 claims abstract description 5
- CSJDCSCTVDEHRN-UHFFFAOYSA-N methane;molecular oxygen Chemical compound C.O=O CSJDCSCTVDEHRN-UHFFFAOYSA-N 0.000 claims description 25
- 238000006243 chemical reaction Methods 0.000 claims description 23
- 229910000805 Pig iron Inorganic materials 0.000 claims description 10
- 229910052799 carbon Inorganic materials 0.000 claims description 6
- 230000000630 rising effect Effects 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- 238000002844 melting Methods 0.000 claims description 4
- 230000008018 melting Effects 0.000 claims description 4
- 239000011241 protective layer Substances 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 239000002699 waste material Substances 0.000 description 12
- 239000007789 gas Substances 0.000 description 7
- 239000003921 oil Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 4
- 238000009749 continuous casting Methods 0.000 description 3
- 238000009628 steelmaking Methods 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 239000012300 argon atmosphere Substances 0.000 description 2
- 229910001570 bauxite Inorganic materials 0.000 description 2
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 239000010436 fluorite Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 239000000779 smoke Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000003483 aging Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
The invention discloses a control method for reducing nitrogen content of molten steel in a converter low-iron-loss mode, belonging to the technical field of steel manufacturing; the method comprises the following steps: controlling the charging temperature of molten iron to 1310-1330 ℃, controlling the silicon content in the molten iron to 0.30-0.50%, controlling the charging proportion of the molten iron to 65-70% and the charging proportion of scrap steel to 30-35%; controlling the iron-steel ratio of the converter to be 720-750 kg/t; after adding scrap steel into the furnace, rocking the furnace back and forth until the flame at the furnace mouth is normal, and baking the scrap steel; adding 50% of slag in the first 4 minutes of converter blowing, adding a small amount of residual slag for many times in 4-8 minutes, controlling the temperature of the furnace, stirring a molten pool back and forth from high to low by an oxygen lance before finishing, adopting nitrogen-argon switching bottom blowing in the converter blowing process, adding a ladle slag modifier before tapping, adding a deoxidizer for alloying, and simultaneously carrying out ladle bottom blowing argon. The control method can control the nitrogen content of the molten steel of the converter to be within 40ppm under the condition that the iron-steel ratio of the converter is as low as 720-750 kg/t.
Description
Technical Field
The invention belongs to the technical field of steel manufacturing, and particularly relates to a control method for reducing nitrogen content of molten steel in a converter in a low iron loss mode.
Background
When the price of scrap steel in the market is lower than that of molten iron, the lower the value of the unit consumption of the molten iron in the steelmaking process is, the lower the production cost is; many steel plants reduce the production cost by increasing the addition amount of scrap steel in the steelmaking process and reducing the unit consumption of molten iron; however, as the unit consumption of molten iron is reduced, the nitrogen control capability in the steelmaking process is weakened, and the nitrogen content is increased. Nitrogen is a detrimental element for most steel grades, and an increase in the nitrogen content of the steel reduces the impact toughness and plasticity of the steel and results in age hardening; nitrogen also greatly increases the ductile-brittle transition temperature of the steel, which results in low temperature temper brittleness of the steel, and nitride also results in hot embrittlement of the steel.
Chinese patent CN109457076a discloses a method for controlling nitrogen content of molten steel, comprising: respectively controlling the nitrogen content in the working procedures of converter smelting, LF refining and slab continuous casting; according to the invention, the nitrogen content in molten steel is controlled by comprehensively controlling the denitrification amount or the nitrogen control amount of the converter smelting, the LF refining and the slab continuous casting process, and the stability of the nitrogen content is ensured. Through improving the denitrification capability of the converter, reducing the LF nitrogen increment, stably controlling the continuous casting process of the plate blank, controlling the nitrogen content of the tundish molten steel to be within 60ppm when the unit consumption of the molten steel is 800kg/t, meeting the performance requirements of steel types and effectively reducing the production cost. However, the control method has complicated procedures, and when the unit consumption of molten iron is 800kg/t, the nitrogen content of the molten steel in the tundish is up to more than 60ppm, and the effect of reducing the nitrogen content of the method is limited.
Accordingly, it is highly desirable to provide a method capable of effectively controlling the nitrogen content of molten steel under low unit consumption conditions of molten iron.
Disclosure of Invention
In view of the above shortcomings in the prior art, one of the purposes of the present invention is to provide a control method for reducing the nitrogen content of molten steel in a low iron loss mode of a converter, which can control the nitrogen content of molten steel at the end point of the converter to be within 40ppm under the condition that the iron-steel ratio of the converter is as low as 720-750 kg/t.
In order to achieve the above purpose, the specific technical scheme of the invention is as follows:
a control method for reducing nitrogen content of molten steel in a converter in a low iron loss mode comprises the following steps:
controlling the charging temperature of molten iron to 1310-1330 ℃, controlling the silicon content in the molten iron to 0.30-0.50%, controlling the charging proportion of the molten iron to 65-70% and the charging proportion of scrap steel to 30-35%; controlling the iron-steel ratio of the converter to be 720-750 kg/t;
after adding scrap steel into the furnace, rocking the furnace back and forth until the flame at the furnace mouth is normal, and baking the scrap steel;
adding 50% of slag in the first 4 minutes of the converter converting process, increasing the rising speed of the furnace temperature in the earlier stage of converting to form a carbon-oxygen reaction in the furnace, then adding the rest slag for a small amount of times in 4-8 minutes, controlling the furnace temperature, stirring a molten pool back and forth from high to low by an oxygen gun before finishing, accelerating the melting of pig iron at the bottom, and ensuring the continuous proceeding of the carbon-oxygen reaction in the furnace;
in the converter converting process, nitrogen-argon switching bottom blowing is adopted, nitrogen bottom blowing is adopted when the converter converting process is started to the oxygen blowing percentage of 30%, and argon bottom blowing is adopted after the oxygen blowing percentage of 30%;
and adding ladle slag modifier in the early stage of tapping to form a protective layer on the surface of molten steel to isolate the molten steel in the ladle from contacting with air, adding deoxidizing alloying elements to deoxidize and alloy, and simultaneously carrying out ladle bottom argon blowing before tapping.
The invention firstly bakes the scrap steel, burns the oil-containing substances in the scrap steel, and utilizes high-temperature combustion to form NO by the N-containing compounds in the scrap steel x The gas is pumped away, so that the nitrogen content of the waste steel belt is reduced; under the condition of low iron-steel ratio, the carbon-oxygen reaction of the converter is weakened, the temperature is insufficient, the carbon-oxygen reaction time in the molten pool is short, and the content of discharged nitrogen is low; the invention improves the rising speed of the temperature of the earlier stage furnace by reducing the adding amount of slag in the earlier stage of converting so as to form the carbon-oxygen reaction in the furnace as soon as possible, and adopts more slag in the middle stageThe batch-less batch feeding mode is adopted, the temperature of a molten pool is kept not to be reduced, the continuous occurrence of the carbon-oxygen reaction in the furnace is ensured, and simultaneously, the molten pool is stirred back and forth from high to low by an oxygen lance before the end point, so that the continuous proceeding of the carbon-oxygen reaction in the furnace is ensured; the invention ensures that the carbon-oxygen reaction of the converter is carried out stably through a series of measures, and utilizes CO gas generated by the carbon-oxygen reaction in the converter to reduce the partial pressure of nitrogen, so that nitrogen overflows from steel and the nitrogen content of molten steel is reduced.
According to the control method, nitrogen content in molten steel is reduced through series measures such as waste steel roasting, converter carbon-oxygen reaction balance control, end point hit rate improvement, steel tapping alloying and the like, and the nitrogen content of the molten steel in the converter is controlled within 40ppm under the condition of 720-750 kg/t converter low iron-steel ratio.
Preferably, the scrap steel comprises the following components in percentage by mass: pig iron is less than or equal to 20 percent, primary briquetting is more than or equal to 60 percent, circulating scrap steel is less than or equal to 20 percent, and tertiary briquetting is less than or equal to 6 percent. According to the invention, the addition amount of pig iron is reduced by adjusting the scrap steel batching structure, so that the nitrogen content brought by scrap steel and pig iron is reduced.
Preferably, the molten iron is charged in a proportion of 68.7% and the scrap steel is charged in a proportion of 31.3%.
Preferably, the end point temperature of converter converting is controlled to be 1610-1630 ℃, and the end point carbon content of converter converting is controlled to be 0.05-0.08%.
Preferably, when the end point temperature is controlled to be lower than 1610 ℃ and the end point C content is lower than 0.05%, adding the ferrosilicon heat generating agent for oxygen spot blowing, and controlling the spot blowing times to be not more than 1 time.
Preferably, argon flowers are 300-500 mm in the ladle bottom argon blowing process.
Compared with the prior art, the invention has the following advantages:
the invention firstly bakes the scrap steel, burns the oil-containing substances in the scrap steel, and utilizes high-temperature combustion to form NO by the N-containing compounds in the scrap steel x The gas is pumped away, so that the nitrogen content of the waste steel belt is reduced; under the condition of low iron-steel ratio, the carbon-oxygen reaction of the converter is weakened, the temperature is insufficient, the carbon-oxygen reaction time in the molten pool is short, and the content of discharged nitrogen is low; the invention improves the earlier stage by reducing the adding amount of slag charge in the earlier stage of convertingThe rising speed of the furnace temperature is used for forming the carbon-oxygen reaction in the furnace as soon as possible, a multi-batch and small-batch feeding mode is adopted in the middle period, the temperature of a molten pool is maintained not to be reduced, the continuous occurrence of the carbon-oxygen reaction in the furnace is ensured, meanwhile, an oxygen gun is used for stirring a molten pool back and forth from high to low before the end point, the continuous occurrence of the carbon-oxygen reaction in the furnace is ensured, the balance of the carbon-oxygen reaction in the converter is maintained through a series of measures, the partial pressure of nitrogen is reduced by utilizing CO gas generated by the carbon-oxygen reaction in the furnace, so that nitrogen overflows from steel, and the nitrogen content of molten steel is reduced.
The control method of the invention reduces nitrogen absorption and nitrogen content by a series of measures such as roasting scrap steel, controlling the carbon-oxygen reaction balance of the converter, improving the end hit rate, alloying steel tapping and the like, and realizes that the nitrogen content of the molten steel of the converter is controlled within 40ppm under the condition of 720-750 kg/t converter low iron-steel ratio.
Detailed Description
The following description of the present invention will be made clearly and fully, and it is apparent that the embodiments described are only some, but not all, of the embodiments of the present invention. All other embodiments, which can be made by one of ordinary skill in the art without undue burden on the person of ordinary skill in the art based on embodiments of the present invention, are within the scope of the present invention.
Example 1
The embodiment provides a control method for reducing nitrogen content of molten steel in a low iron loss mode of a converter, which comprises the following steps:
s1, controlling the charging temperature of molten iron to 1310 ℃, controlling the silicon content in the molten iron to 0.50%, controlling the charging proportion of the molten iron to 68.7% and the charging proportion of scrap steel to 31.3%; controlling the iron-steel ratio of the converter to be 735kg/t;
s2, controlling the end point temperature of converter converting to 1610 ℃, and controlling the end point carbon content of converter converting to 0.05%;
s3, adding the waste steel into a furnace, rocking the furnace back and forth (rocking the furnace forward to a tilting angle of 80 degrees and rocking the furnace backward to a tilting angle of 50 degrees) to bake the waste steel, burning oil substances in the waste steel until the flame at the furnace mouth is free from dense smoke, and burning the oil substances containing C, H, N compounds in the waste steel at a high temperature in the furnace to form NO x Gas is pumped away to avoidThe molten steel is prevented from entering;
s4, adjusting ingredients of scrap steel, wherein the proportion of pig iron in the scrap steel is 15%, the proportion of primary briquetting or reinforcing steel bar briquetting is 69%, the proportion of factory internal circulation scrap steel is 10%, and the proportion of tertiary briquetting or industrial packaging block is 6%;
s5, adding 50% of slag in the first 4 minutes of the converter converting process, increasing the rising speed of the furnace temperature in the earlier stage of converting to form a carbon-oxygen reaction in the furnace, then adding a small amount of residual slag for many times in 4-8 minutes, controlling the furnace temperature, stirring a molten pool back and forth from high to low by an oxygen lance before the end point, accelerating the melting of pig iron at the bottom, and ensuring the continuous proceeding of the carbon-oxygen reaction in the furnace;
s6, adopting nitrogen-argon switching bottom blowing in the converter converting process, adopting nitrogen bottom blowing in the period from the opening blowing to the oxygen blowing percentage of 30%, and adopting argon bottom blowing in the period from the oxygen blowing percentage of 30% to the tapping end;
s7, when the end point temperature is controlled to be lower than 1610 ℃ or the end point C content is controlled to be lower than 0.05%, adding a ferrosilicon heat generating agent, then performing oxygen spot blowing, and controlling the spot blowing times to be less than or equal to 1 time;
s8, adding ladle slag modifier (lime, fluorite and bauxite) before tapping to modify, forming a protective layer on the surface of molten steel to isolate the molten steel in the ladle from contacting with air, and then adding deoxidizing alloying elements to deoxidize and alloy; and meanwhile, argon is blown into the ladle at the bottom before tapping, so that argon atmosphere is filled in the ladle, and the contact between molten steel and high-temperature air in the ladle in the tapping process is reduced.
According to the control method of the embodiment, nitrogen content is reduced through a series of measures such as waste steel roasting, converter carbon-oxygen reaction balance control, end point hit rate improvement, point blowing times reduction, steel tapping alloying and the like, and after the control of the method, the nitrogen content in the molten steel of the converter is within 40 ppm.
Example 2
The embodiment provides a control method for reducing nitrogen content of molten steel in a low iron loss mode of a converter, which comprises the following steps:
s1, controlling the charging temperature of molten iron to 1330 ℃, controlling the silicon content in the molten iron to 0.30%, controlling the charging proportion of the molten iron to 70% and the charging proportion of scrap steel to 30%; controlling the iron-steel ratio of the converter to be 750kg/t;
s2, controlling the end point temperature of converter converting to 1630 ℃ and controlling the end point carbon content of converter converting to be 0.08%;
s3, adding the waste steel into a furnace, rocking the furnace back and forth (rocking the furnace forward to a tilting angle of 80 degrees and rocking the furnace backward to a tilting angle of 50 degrees) to bake the waste steel, burning oil substances in the waste steel until the flame at the furnace mouth is free from dense smoke, and burning the oil substances containing C, H, N compounds in the waste steel at a high temperature in the furnace to form NO x The gas is pumped away, so that the gas is prevented from entering molten steel;
s4, adjusting ingredients of scrap steel, wherein the proportion of pig iron in the scrap steel is 10%, the proportion of primary briquetting or reinforcing steel bar briquetting is 75%, the proportion of factory internal circulation scrap steel is 10%, and the proportion of tertiary briquetting or industrial packaging block is 5%;
s5, adding 50% of slag in the first 4 minutes of the converter converting process, increasing the rising speed of the furnace temperature in the earlier stage of converting to form a carbon-oxygen reaction in the furnace, then adding a small amount of residual slag for many times in 4-8 minutes, controlling the furnace temperature, stirring a molten pool back and forth from high to low by an oxygen lance before the end point, accelerating the melting of pig iron at the bottom, and ensuring the continuous proceeding of the carbon-oxygen reaction in the furnace;
s6, adopting nitrogen-argon switching bottom blowing in the converter converting process, adopting nitrogen bottom blowing in the period from the opening blowing to the oxygen blowing percentage of 30%, and adopting argon bottom blowing in the period from the oxygen blowing percentage of 30% to the tapping end;
s7, when the end point temperature is controlled to be lower than 1610 ℃ or the end point C content is controlled to be lower than 0.05%, adding a ferrosilicon heat generating agent, then performing oxygen spot blowing, and controlling the spot blowing times to be less than or equal to 1 time;
s8, adding ladle slag modifier (lime, fluorite and bauxite) before tapping to modify, forming a protective layer on the surface of molten steel to isolate the molten steel in the ladle from contacting with air, and then adding deoxidizing alloying elements to deoxidize and alloy; and meanwhile, argon is blown into the ladle at the bottom before tapping, so that argon atmosphere is filled in the ladle, and the contact between molten steel and high-temperature air in the ladle in the tapping process is reduced.
After the control by the method, the nitrogen content in the molten steel of the converter is within 40 ppm.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (6)
1. The control method for reducing the nitrogen content of molten steel in the low-iron-loss mode of the converter is characterized by comprising the following steps of:
controlling the charging temperature of molten iron to 1310-1330 ℃, controlling the silicon content in the molten iron to 0.30-0.50%, controlling the charging proportion of the molten iron to 65-70% and the charging proportion of scrap steel to 30-35%; controlling the iron-steel ratio of the converter to be 720-750 kg/t;
after adding scrap steel into the furnace, rocking the furnace back and forth until the flame at the furnace mouth is normal, and baking the scrap steel;
adding 50% of slag in the first 4 minutes of the converter converting process, increasing the rising speed of the furnace temperature in the earlier stage of converting to form a carbon-oxygen reaction in the furnace, then adding the rest slag for a small amount of times in 4-8 minutes, controlling the furnace temperature, stirring a molten pool back and forth from high to low by an oxygen gun before finishing, accelerating the melting of pig iron at the bottom, and ensuring the continuous proceeding of the carbon-oxygen reaction in the furnace;
in the converter converting process, nitrogen-argon switching bottom blowing is adopted, nitrogen bottom blowing is adopted when the converter converting process is started to the oxygen blowing percentage of 30%, and argon bottom blowing is adopted after the oxygen blowing percentage of 30%;
and adding ladle slag modifier in the early stage of tapping to form a protective layer on the surface of molten steel to isolate the molten steel in the ladle from contacting with air, adding deoxidizing alloying elements to deoxidize and alloy, and simultaneously carrying out ladle bottom argon blowing before tapping.
2. The control method for reducing nitrogen content of molten steel in a low iron loss mode of a converter according to claim 1, wherein the scrap steel comprises the following components in percentage by mass: pig iron is less than or equal to 20 percent, primary briquetting is more than or equal to 60 percent, circulating scrap steel is less than or equal to 20 percent, and tertiary briquetting is less than or equal to 6 percent.
3. The control method for reducing nitrogen content of molten steel in a low iron loss mode of a converter according to claim 1, wherein the charging ratio of molten iron is 68.7% and the charging ratio of scrap steel is 31.3%.
4. The control method for reducing nitrogen content of molten steel in a low iron loss mode of a converter according to claim 1, wherein the end point temperature of converter blowing is controlled to be 1610-1630 ℃ and the end point carbon content of converter blowing is controlled to be 0.05% -0.08%.
5. The method for controlling nitrogen content of molten steel in a low iron loss mode of a converter according to claim 4, wherein when the end point temperature is controlled to be lower than 1610 ℃ and the end point C content is controlled to be lower than 0.05%, adding a ferrosilicon heat generating agent to supply oxygen for spot blowing, and controlling the number of times of spot blowing to be not more than 1.
6. The control method for reducing nitrogen content of molten steel in a low iron loss mode of a converter according to claim 1, wherein argon flowers in the ladle bottom argon blowing process are 300-500 mm.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311193862.6A CN117467884A (en) | 2023-09-15 | 2023-09-15 | Control method for reducing nitrogen content of molten steel in converter in low iron loss mode |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311193862.6A CN117467884A (en) | 2023-09-15 | 2023-09-15 | Control method for reducing nitrogen content of molten steel in converter in low iron loss mode |
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