CN115558736A - Method for improving molten steel cleanliness of IF steel - Google Patents
Method for improving molten steel cleanliness of IF steel Download PDFInfo
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- CN115558736A CN115558736A CN202211284742.2A CN202211284742A CN115558736A CN 115558736 A CN115558736 A CN 115558736A CN 202211284742 A CN202211284742 A CN 202211284742A CN 115558736 A CN115558736 A CN 115558736A
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- 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
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
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- 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
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- 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
- C21C7/064—Dephosphorising; Desulfurising
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- 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
- C21C7/068—Decarburising
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- 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
- C21C7/10—Handling in a vacuum
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- 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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- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a method for improving molten steel cleanliness of IF steel, and relates to the technical field of steel smelting. The method comprises the following steps: s1, molten iron pretreatment: carrying out desulfurization treatment on the molten iron to obtain desulfurized molten iron; s2, smelting in a converter: adding the waste steel into the desulfurized molten iron prepared in the step S1 to prepare molten steel; s3, pre-deoxidation: adding carbon powder into the molten steel prepared in the step S2 to prepare pre-deoxidized molten steel; s4, RH decarburization: RH decarburization is carried out on the pre-deoxidized molten steel obtained in the step S3, and IF molten steel is obtained; the mass ratio of the scrap steel to the desulfurized molten iron is 1:4 or more. The method firstly carries out desulfurization treatment on the molten iron, so that the sulfur content in the molten iron is reduced; adding the scrap steel into the desulfurized molten iron, thereby realizing the recycling of the scrap steel; meanwhile, the unit consumption of molten iron is reduced, and the production cost is reduced.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a method for improving molten IF steel cleanliness.
Background
IF steel is also called interstitial free steel, has excellent deep drawing performance and is widely applied to industries of automobiles, household appliances and the like. In order to further improve the deep drawing performance of the IF steel, the quality of the IF steel is improved; the C, S and N elements in IF steel need to be strictly controlled; meanwhile, in order to obtain good surface quality, it is required that the steel should not contain large cluster-like inclusions, especially inclusions having a large diameter (20 μm or more), because such inclusions are highly likely to form cold-rolled surface defects during cold rolling, resulting in defective steel sheets. And Al generated by deoxidation of molten iron in the production process of IF steel 2 O 3 The inclusion is difficult to be completely removed, and is easy to be gathered and grown up again in the continuous casting process, and the nodulation is generated at the water gap, so that the water gap is blocked, the production stability is influenced, and the internal cleanliness of steel is reduced.
The related art discloses a method for improving cleanliness of IF steel, which comprises the following steps:
a. a converter process: controlling the molten steel carbon to be 0.05-0.08 wt%; reducing the slag amount at the end point of the converter and ensuring the clearance of the steel ladle to be 400-600 mm;
b. refining in an LF furnace: LF enters a station and is added with 1 kg/t-3 kg/t of active lime and 0.3 kg/t-1.0 kg/t of CaC for submerged arc heating;
c. RH refining: adding a steel deep decarbonizing agent into the vacuum chamber when the RH decarburization treatment is carried out for 4-8 min; after the alloying is finished, adding a molten steel inclusion remover into the vacuum chamber in batches;
d. slab continuous casting: in the continuous casting process, the calcium aluminate tundish covering agent is adopted to obtain the high-cleanliness IF steel with the C content less than or equal to 0.002 wt%. The process is complicated to operate and it is difficult to reduce the oxygen content at low cost.
Therefore, the invention provides a method for improving the cleanliness of molten steel of IF steel, which reduces the oxygen content of the IF steel and has low production cost.
Disclosure of Invention
An object of the present invention is to provide a method for improving cleanliness of molten IF steel, which solves at least one of the problems and disadvantages of the background art described above.
The method comprises the following specific steps: the invention provides a method for improving molten steel cleanliness of IF steel, which comprises the following steps:
s1, pretreating molten iron;
carrying out desulfurization treatment on the molten iron to obtain desulfurized molten iron;
s2, smelting in a converter:
adding the waste steel into the desulfurized molten iron prepared in the step S1 to prepare molten steel;
s3, pre-deoxidation:
adding carbon powder into the molten steel prepared in the step S2 to prepare pre-deoxidized molten steel;
s4, RH decarburization:
RH decarburization is carried out on the pre-deoxidized molten steel obtained in the step S3, and IF molten steel is obtained;
the mass ratio of the scrap steel to the desulfurized molten iron is 1:4 or more.
According to one of the technical schemes of the method, the method at least has the following beneficial effects:
the method firstly carries out desulfurization treatment on the molten iron, so that the sulfur content in the molten iron is reduced; adding the scrap steel into the desulfurized molten iron, thereby realizing the recycling of the scrap steel; meanwhile, the single consumption of molten iron is reduced, and the production cost is reduced; after smelting in a converter, adding carbon powder for pre-deoxidation, thereby realizing the accurate control of the oxygen content in the molten steel; in addition, aluminum is not required to be added in the RH decarburization process, so that the RH treatment time is reduced; in the related technology, the vacuum degree can be damaged by adding aluminum in the RH decarburization process, so that the RH treatment time is prolonged; meanwhile, the invention also reduces Al brought by aluminum addition for pre-deoxidation in the RH decarburization stage 2 O 3 The problem of increase; improves the cleanliness of molten steel, and reduces the risk of nodulation and blockage (excessive Al) in the casting process 2 O 3 In the casting process, the nozzle is nodulated at the nozzle to cause nozzle blockage), and simultaneously, the consumption of the aluminum block is reduced, and the production cost is saved.
According to some embodiments of the present invention, the mass fraction of sulfur in the desulfurized molten iron is 0.0015% or less.
According to some embodiments of the invention, the desulphurization is followed by a drossing treatment.
According to some embodiments of the invention, the pretreatment is KR desulfurization.
According to some embodiments of the invention, the sulfur content in the scrap steel is 0.04% or less.
According to some embodiments of the invention, the temperature of the molten steel in step S2 is 1660 ℃ to 1700 ℃.
According to some embodiments of the invention, the oxygen content of the molten steel in step S2 is 400ppm to 1500ppm by mass.
According to some embodiments of the invention, the oxygen content of the molten steel in step S2 is 600ppm to 1500ppm by mass.
According to some embodiments of the invention, the carbon content fraction of the molten steel in step S2 is 0.02% to 0.05%.
Controlling the mass fractions of oxygen element and carbon element in the molten steel to be in the above ranges; realize the counter-rotating furnaceProvides the RH molten steel with stable temperature, oxygen content and carbon content, reduces Al brought by large amount of oxygen blowing or oxygen blowing and aluminum adding temperature rising operation in the RH process in the later period 2 O 3 The increase of the Al content improves the molten steel cleanliness of the IF steel (reduces Al content) 2 O 3 Generation of (1); reducing the risk of nozzle clogging and clogging, and reducing the quality risk caused by surface inclusions).
According to some embodiments of the invention, the amount of carbon powder added in step S3 is determined by:
C-0.05％≤1.33×(A+B)≤C-0.03％；
wherein A is the mass fraction of carbon in the carbon powder;
b is the mass fraction of carbon in the molten steel in the step S2;
and C is the mass fraction of oxygen in the molten steel in the step S2.
Wherein 1.33 is the relative atomic mass ratio of oxygen atoms to carbon atoms; 0.03% is the lower limit of the oxygen mass content after decarburization; 0.05% is the upper limit of the oxygen mass content after decarburization.
According to some embodiments of the present invention, the degree of vacuum of the RH decarburization in the step S4 is 1000Pa or less.
Quickening the decarburization speed, reducing the decarburization time and reducing the temperature drop.
According to some embodiments of the present invention, when the target carbon content of the molten steel of the IF steel is 30ppm to 60ppm, the degree of vacuum during RH decarburization is 600Pa to 1000Pa.
According to some embodiments of the present invention, when the target C content of the molten steel of the IF steel is < 30ppm, the degree of vacuum during RH decarburization is 133Pa or less.
According to some embodiments of the invention, the RH decarburization time in step S4 is within 20min.
The RH decarburization time is controlled within the range so as to avoid the increase of temperature drop in the process caused by overlong time, reduce the degree of superheat and increase the slag rolling probability.
According to some embodiments of the present invention, when the target carbon content of the molten steel of the IF steel is 30ppm to 60ppm, the RH decarburization time is within 14 min.
According to some embodiments of the present invention, when the target C content of the molten IF steel is less than 30ppm, the RH decarburization time is 15min to 20min.
According to some embodiments of the present invention, the oxygen content in the molten IF steel in step S4 is 0.03% to 0.05%.
According to the requirements of carbon and oxygen contents at the end point of decarburization, the decarburization time and the decarburization vacuum degree are determined, the steam consumption is reduced, and meanwhile, the optimal cycle time is used for treatment, so that the temperature drop caused by overlong treatment time is reduced, and the slag rolling risk caused by low superheat degree or oxygen blowing temperature rise is reduced.
According to some embodiments of the invention, the flow of the circulating argon during the RH decarburization process is between 180NL/min and 200NL/min.
According to some embodiments of the invention, the circulating argon flow during the RH decarburization process is 190NL/min.
According to some embodiments of the invention, the mass fraction of phosphorus element in the waste steel material is below 0.035%.
According to some embodiments of the present invention, the mass fraction of elemental sulfur in the scrap steel is 0.04% or less.
According to some embodiments of the present invention, the mass fraction of the alloy elements that are hard to oxidize in the waste steel material is 0.05% or less.
According to some embodiments of the invention, the hard-to-oxidize alloying element comprises at least one of copper or arsenic.
According to some embodiments of the invention, the scrap steel material further comprises iron.
The invention has at least the following beneficial effects:
according to the method, under the condition of low molten iron unit consumption, carbon powder is added for pre-deoxidation after converter tapping, so that the residual oxygen content in the molten steel is controlled to be 0.04% +/-0.01% after RH decarburization is finished, and the decarburization period treatment time is reduced (in the related technology, aluminum is added in the RH decarburization process to destroy the vacuum degree, so that the RH decarburization treatment time is prolonged); simultaneously reduces Al brought by aluminum addition in the RH decarburization stage for pre-deoxidation operation in the related art 2 O 3 Increased shadowImprove the molten steel cleanliness of IF steel (without increasing Al production) 2 O 3 (ii) a The risk of nozzle clogging and blockage (excessive Al) is reduced 2 O 3 Nodulation at the nozzle during casting, causing nozzle clogging)); meanwhile, the consumption of the aluminum block is reduced, and the cost is saved.
Detailed Description
The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention.
In the description of the present invention, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The method for improving the cleanliness of the molten IF steel in the embodiment of the invention comprises the following steps:
s1, pretreating molten iron;
carrying out desulfurization treatment on the molten iron to obtain desulfurized molten iron;
feeding molten iron smelted by a blast furnace into a KR desulfurization station for molten iron pre-desulfurization, controlling S in the desulfurized molten iron to be less than or equal to 0.0015 percent (mass fraction), and carrying out slagging-off treatment after desulfurization;
s2, smelting in a converter:
adding the waste steel into the desulfurized molten iron prepared in the step S1 to prepare molten steel;
wherein the mass ratio of the waste steel to the desulfurized molten iron is 1:4 or more.
The molten steel prepared in the step is tested by TSO, and the test result is as follows:
the temperature is 1660-1700 ℃, the end point oxygen is 600-1500 ppm (mass fraction), and the end point carbon is 0.02-0.05% (mass fraction).
S3, pre-deoxidation:
adding carbon powder into the molten steel prepared in the step S2 to prepare pre-deoxidized molten steel;
during tapping, carbon powder is added into the ladle.
The addition amount of the carbon powder in the step S3 is determined in the following way:
C-0.05％≤1.33×(A+B)≤C-0.03％；
wherein A is the mass fraction of carbon in the carbon powder;
b is the mass fraction of carbon in the molten steel in the step S2;
and C is the mass fraction of oxygen in the molten steel in the step S2.
S4, RH decarburization:
RH decarburization is carried out on the pre-deoxidized molten steel obtained in the step S3, and IF molten steel is obtained;
the circulating argon flow was 190NL/min.
When the target carbon content of the molten IF steel is 30-60 ppm, the vacuum degree is 600-1000 Pa in the RH decarburization process, and the decarburization time is within 14 min;
when the target C content of molten IF steel is less than 30ppm, the vacuum degree is less than 133Pa in the RH decarburization process, and the decarburization time is 15-20 min.
The invention is further illustrated by the following examples.
Example 1
The embodiment is a method for improving the cleanliness of molten IF steel, which comprises the following steps:
s1, pretreating molten iron;
carrying out desulfurization treatment on the molten iron to obtain desulfurized molten iron;
conveying the molten iron smelted by the blast furnace into a KR desulfurization station, adding enough desulfurizer for stirring, performing molten iron pre-desulfurization, wherein the mass content of S in the desulfurized molten iron is less than 0.0015%, and performing slagging-off treatment after desulfurization;
s2, smelting in a converter:
adding the waste steel into the desulfurized molten iron prepared in the step S1 to prepare molten steel;
the mass proportion of the scrap steel in the total loading amount is 21.4%, the main component of the scrap steel is iron, the rest of phosphorus is less than or equal to 0.035%, sulfur is less than or equal to 0.04%, and alloy elements (copper and arsenic) which are difficult to oxidize are less than or equal to 0.05%, so that waste judgment caused by the excessive elements after the desulfurized molten iron is added into the scrap steel is avoided.
The molten steel prepared in the step is tested by TSO, and the test result is as follows:
the temperature was 1680 ℃, the end point oxygen was 967ppm (mass fraction), and the end point carbon was 0.0248% (mass fraction).
S3, pre-deoxidation:
adding carbon powder into the 220 tons of molten steel prepared in the step S2 to prepare pre-deoxidized molten steel;
during tapping, 36kg of carbon powder with carbon content of more than 95 percent is added into a ladle.
S4, RH decarburization:
RH decarburization is carried out on the pre-deoxidized molten steel prepared in the step S3, and IF molten steel is prepared;
in the RH decarburization process, the ultimate vacuum degree is 81Pa, and the circulating argon flow is 190NL/min; the RH decarburization time was 17min.
In the embodiment, the mass fraction of oxygen in the IF steel molten steel is 0.0363%; the mass fraction of carbon was 19ppm.
Example 2
The embodiment is a method for improving the cleanliness of molten IF steel, which comprises the following steps:
s1, pretreating molten iron;
carrying out desulfurization treatment on the molten iron to obtain desulfurized molten iron;
conveying the molten iron smelted by the blast furnace into a KR desulfurization station, adding enough desulfurizer for stirring, pre-desulfurizing the molten iron, and carrying out slagging-off treatment after desulfurization, wherein the S content in the molten iron is less than 0.0015%;
s2, smelting in a converter:
adding the waste steel into the desulfurized molten iron prepared in the step S1 to prepare molten steel;
wherein the mass proportion of the scrap steel in the total loading is 22.3 percent, the main component of the scrap steel is iron, the rest phosphorus is less than or equal to 0.035 percent, the sulfur is less than or equal to 0.04 percent, and the alloy elements (copper and arsenic) which are difficult to oxidize are less than or equal to 0.05 percent, thereby ensuring that the judgment of waste caused by the overproof of the elements after the desulfurized molten iron is added into the scrap steel can not be carried out.
The molten steel prepared in the step is tested by TSO, and the test result is as follows:
the temperature was 1668 ℃, the end point oxygen was 1126ppm (mass fraction), and the end point carbon was 0.0322% (mass fraction).
S3, pre-deoxidation:
adding carbon powder into the 217 ton molten steel prepared in the step S2 to prepare pre-deoxidized molten steel;
during tapping, 45kg of carbon powder was added to the ladle.
S4, RH decarburization:
RH decarburization is carried out on the pre-deoxidized molten steel obtained in the step S3, and IF molten steel is obtained;
in the RH decarburization process, the vacuum degree is 700Pa, and the circulating argon flow is 190NL/min; the RH decarburization time was 12min.
In the embodiment, the mass fraction of oxygen in the IF steel water is 0.0419%; the mass fraction of carbon was 39ppm.
Example 3
The embodiment is a method for improving the cleanliness of molten IF steel, which comprises the following steps:
s1, pretreating molten iron;
conveying the molten iron smelted by the blast furnace into a KR desulfurization station, adding enough desulfurizer for stirring, pre-desulfurizing the molten iron, and carrying out slagging-off treatment after desulfurization, wherein the S content in the molten iron is less than 0.0015%;
s2, smelting in a converter:
adding the waste steel into the desulfurized molten iron prepared in the step S1 to prepare molten steel;
the mass ratio of the waste steel to the desulfurized molten iron is 1:4, the main components of the waste steel are iron, the rest of phosphorus is less than or equal to 0.035%, sulfur is less than or equal to 0.04%, and alloy elements (copper and arsenic) which are difficult to oxidize are less than or equal to 0.05%, so that waste judgment caused by the fact that the elements exceed the standard after the desulfurized molten iron is added into the waste steel is avoided.
The molten steel prepared in the step is tested by TSO, and the test result is as follows:
the temperature was 1669 ℃, the end point oxygen was 869ppm (mass fraction), and the end point carbon was 0.0216% (mass fraction).
S3, pre-deoxidation:
adding carbon powder into 213 tons of molten steel prepared in the step S2 to prepare pre-deoxidized molten steel;
during tapping, 20kg of carbon powder was added to the ladle.
S4, RH decarburization:
RH decarburization is carried out on the pre-deoxidized molten steel obtained in the step S3, and IF molten steel is obtained;
in the RH decarburization process, the ultimate vacuum degree is 72Pa, and the circulating argon flow is 190NL/min; the RH decarburization time was 20min.
In the embodiment, the mass fraction of oxygen in the IF steel molten steel is 0.0397%; the mass fraction of carbon was 12ppm.
In embodiments 1 to 3 of the present invention, the oxygen content in molten steel is controlled by recarburizing the molten steel during tapping according to the temperature, carbon content and oxygen content of the molten steel measured at the end point of the converter, so as to control the addition of aluminum to deoxidize in the RH decarburization process due to too high oxygen content in the molten steel, thereby saving the cost of the aluminum deoxidizer and effectively reducing the Al content while reducing the Al content 2 O 3 Thereby reducing the generation of surface quality defects of the cold-rolled sheet.
In conclusion, the method firstly carries out desulfurization treatment on the molten iron, so that the sulfur content in the molten iron is reduced; adding the scrap steel into the desulfurized molten iron, thereby realizing the recycling of the scrap steel; meanwhile, the single consumption of molten iron is reduced, and the production cost is reduced; after smelting in a converter, carbon powder is added for pre-deoxidation, so that the accurate oxygen content in the molten steel is realizedControlling; in addition, aluminum is not required to be added in the RH decarburization process, so that the RH treatment time is reduced; in the related technology, the vacuum degree can be damaged by adding aluminum in the RH decarburization process, so that the RH treatment time is prolonged; meanwhile, the invention also reduces Al brought by aluminum addition for pre-deoxidation in the RH decarburization stage 2 O 3 The problem of increase; improves the cleanliness of molten steel, and reduces the risk of nodulation and blockage (excessive Al) in the casting process 2 O 3 In the casting process, the nozzle is nodulated at the nozzle to cause nozzle blockage), and simultaneously, the consumption of the aluminum block is reduced, and the production cost is saved.
The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only examples of the present invention, and should not be construed as limiting the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method for improving molten steel cleanliness of IF steel is characterized by comprising the following steps:
s1, pretreating molten iron;
carrying out desulfurization treatment on the molten iron to obtain desulfurized molten iron;
s2, smelting in a converter:
adding the waste steel into the desulfurized molten iron prepared in the step S1 to prepare molten steel;
s3, pre-deoxidation:
adding carbon powder into the molten steel prepared in the step S2 to prepare pre-deoxidized molten steel;
s4, RH decarburization:
RH decarburization is carried out on the pre-deoxidized molten steel obtained in the step S3, and IF molten steel is obtained;
the mass ratio of the scrap steel to the desulfurized molten iron is 1:4 or more.
2. The method for improving the cleanliness of molten IF steel according to claim 1, wherein the sulfur content in the molten desulfurized molten iron is below 0.0015% by mass.
3. The method for improving the cleanliness of molten IF steel according to claim 1, wherein the sulfur content in said scrap is less than or equal to 0.04%.
4. The method for improving the cleanliness of molten IF steel according to claim 1, wherein the temperature of the molten IF steel in step S2 is 1660-1700 ℃.
5. The method for improving cleanliness of molten IF steel according to claim 1, wherein oxygen content of said molten IF steel in step S2 is 400 ppm-1500 ppm by mass.
6. The method for improving the cleanliness of molten IF steel according to claim 1, wherein the molten IF steel in step S2 has a carbonaceous content of 0.02-0.05%.
7. The method for improving molten steel cleanliness of the IF steel according to any one of claims 1 to 6, wherein the addition amount of the carbon powder in the step S3 is determined by:
C-0.05％≤1.33×(A+B)≤C-0.03％；
wherein A is the mass fraction of carbon in the carbon powder;
b is the mass fraction of carbon in the molten steel in the step S2;
and C is the mass fraction of oxygen in the molten steel in the step S2.
8. The method for improving cleanliness of molten IF steel according to any one of claims 1 to 6, wherein vacuum degree of RH decarburization in step S4 is 1000Pa or less.
9. The method for improving cleanliness of molten IF steel according to any one of claims 1 to 6, wherein the RH decarburization time in step S4 is within 20min.
10. The method for improving cleanliness of molten IF steel according to any one of claims 1 to 6, wherein oxygen content in the molten IF steel in step S4 is 0.03-0.05%.
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| CN114182156A (en) * | 2020-09-14 | 2022-03-15 | 上海梅山钢铁股份有限公司 | Production method of low-aluminum carbon structural molten steel |
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