CN113088628A - LF refining method of low-carbon steel - Google Patents
LF refining method of low-carbon steel Download PDFInfo
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- CN113088628A CN113088628A CN202110347573.1A CN202110347573A CN113088628A CN 113088628 A CN113088628 A CN 113088628A CN 202110347573 A CN202110347573 A CN 202110347573A CN 113088628 A CN113088628 A CN 113088628A
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- 238000007670 refining Methods 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 39
- 229910001209 Low-carbon steel Inorganic materials 0.000 title claims abstract description 13
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 102
- 239000010959 steel Substances 0.000 claims abstract description 102
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 86
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 48
- 229910052786 argon Inorganic materials 0.000 claims abstract description 43
- 229910010271 silicon carbide Inorganic materials 0.000 claims abstract description 41
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims abstract description 39
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 36
- 238000003756 stirring Methods 0.000 claims abstract description 33
- 238000007664 blowing Methods 0.000 claims abstract description 23
- 239000002893 slag Substances 0.000 claims abstract description 21
- 238000004458 analytical method Methods 0.000 claims abstract description 18
- 239000000956 alloy Substances 0.000 claims abstract description 17
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 16
- 238000003723 Smelting Methods 0.000 claims abstract description 15
- 238000009792 diffusion process Methods 0.000 claims abstract description 11
- 238000010079 rubber tapping Methods 0.000 claims abstract description 8
- 238000005070 sampling Methods 0.000 claims abstract description 4
- 230000005540 biological transmission Effects 0.000 claims description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 2
- 239000011449 brick Substances 0.000 claims description 2
- 229910052593 corundum Inorganic materials 0.000 claims description 2
- 229910001845 yogo sapphire Inorganic materials 0.000 claims description 2
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 239000000463 material Substances 0.000 abstract description 3
- 229910000604 Ferrochrome Inorganic materials 0.000 description 13
- 239000003795 chemical substances by application Substances 0.000 description 13
- 229910052710 silicon Inorganic materials 0.000 description 8
- 229910000616 Ferromanganese Inorganic materials 0.000 description 7
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 description 7
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 5
- 235000011941 Tilia x europaea Nutrition 0.000 description 5
- 239000004571 lime Substances 0.000 description 5
- 229910001309 Ferromolybdenum Inorganic materials 0.000 description 4
- 238000007689 inspection Methods 0.000 description 4
- 229910000720 Silicomanganese Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910000519 Ferrosilicon Inorganic materials 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000003607 modifier Substances 0.000 description 2
- 239000005997 Calcium carbide Substances 0.000 description 1
- 229910001200 Ferrotitanium Inorganic materials 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- XJKVPKYVPCWHFO-UHFFFAOYSA-N silicon;hydrate Chemical compound O.[Si] XJKVPKYVPCWHFO-UHFFFAOYSA-N 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- CLZWAWBPWVRRGI-UHFFFAOYSA-N tert-butyl 2-[2-[2-[2-[bis[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]amino]-5-bromophenoxy]ethoxy]-4-methyl-n-[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]anilino]acetate Chemical compound CC1=CC=C(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(OCCOC=2C(=CC=C(Br)C=2)N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)=C1 CLZWAWBPWVRRGI-UHFFFAOYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
-
- 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
- C21C7/0025—Adding carbon material
-
- 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
- C21C7/072—Treatment with gases
-
- 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
- C21C7/076—Use of slags or fluxes as treating agents
-
- 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
Abstract
The invention relates to an LF refining method of low-carbon steel, which comprises the following steps: 1) controlling the carbon at the end point of the primary smelting furnace to be 0.07-0.09%, and adding alloy and slag charge into steel along with the flow of the steel in the tapping process of the primary smelting furnace; 2) after the molten steel reaches a refining position, power is supplied, silicon carbide and a carburant are added for diffusion deoxidation, and argon is blown from the bottom of a ladle; 3) after slagging, power is off, argon bottom blowing stirring is carried out, a sample is taken for analysis, the analysis result is obtained, the content of the molten steel components is adjusted according to the target component requirement, then argon bottom blowing stirring is carried out, sampling analysis is carried out again until the components of the molten steel meet the target components, and then steel is tapped to obtain the low-carbon steel. The invention quantifies the using amount of the recarburizer, silicon carbide and other deoxidizing materials and the bottom-blown argon in the refining diffusion deoxidizing process, reduces the influence of human factors, solves the problems of large change of the recarburizer and the silicon carbide in the refining diffusion deoxidizing process of the molten steel and large fluctuation of the molten steel components, and is beneficial to the standardized operation of the molten steel in the refining process.
Description
Technical Field
The invention belongs to the technical field of steel making, and particularly relates to an LF refining method of low-carbon steel.
Background
The LF refining process mainly undertakes the tasks of 'two-time separation' and 'two-time adjustment' of molten steel, namely deoxidation, desulfurization, molten steel component adjustment and molten steel temperature adjustment. The general refining process is that during the tapping process of a primary smelting furnace, a proper amount of alloy and slag are added into steel, then the molten steel is transferred to a refining station, temperature is measured firstly, then slag melting and temperature raising are carried out simultaneously, materials such as silicon carbide, calcium carbide and aluminum particles are added into the steel for deoxidation, then sampling is carried out for the first time to analyze the components of the molten steel, the components of the molten steel are adjusted according to the inspection result of the first sample, after uniform stirring, the second sample is taken for analysis, and the components of the molten steel are finely adjusted according to the inspection result of the second sample.
The existing LF refining process has the following defects: the adjustment of the components of the molten steel is mainly put after a sample is taken once, when the carbon component in the steel is adjusted, the carburetion amount of low-carbon steel is often more than or equal to 0.05 percent, and large argon stirring is required for a long time in the carburetion process, so that the molten steel is inevitably contacted with air, nitrogen and oxygen are absorbed by the molten steel, and the quality of the molten steel is adversely affected.
Disclosure of Invention
Based on the defects, the invention aims to develop an LF refining method suitable for low-carbon steel production aiming at the defects of the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a low-carbon steel LF refining method, which comprises the following steps:
1) controlling the carbon at the end point of the primary smelting furnace to be 0.07-0.09%, and adding alloy and slag charge into steel along with the flow of the steel in the tapping process of the primary smelting furnace;
2) after the molten steel reaches a refining position, power is supplied, silicon carbide and a carburant are added for diffusion deoxidation, and argon is blown from the bottom of a ladle;
wherein the dosage of the silicon carbide is 70-90 kg/furnace steel,
the predicted recarburization amount of the silicon carbide is the addition amount of the silicon carbide and the carbon content of the silicon carbide and the recarburization coefficient of the silicon carbide/molten steel amount/1000, and the recarburization coefficient of the silicon carbide ranges from 0.03 to 0.1; the finer the granularity of the silicon carbide is, the smaller the recarburization coefficient of the silicon carbide is, the larger the stirring argon flow is, the larger the coefficient is, and the better the fluidity of the refining slag is.
The adding amount of carburant for diffusion deoxidation is (the carburant of a refining target-the carburant of an electric furnace alloy-0.02% -the predicted carburant of silicon carbide) ÷ the carburant carbon content multiplied by the carburant coefficient multiplied by 100; the value range of the recarburization coefficient is 0.05-0.15, wherein the recarburization coefficient of the recarburization agent is related to the particle size of the recarburization agent, the flow of the stirring argon gas, the fluidity of the refining slag and other factors; the finer the particle size of the recarburizer is, the larger the recarburization coefficient of the recarburizer is, the larger the stirring argon flow is, the smaller the coefficient is, and the better the fluidity of the refining slag is, the smaller the coefficient is. Generally, the recarburizers and the refining slag used in a steel mill are fixed, and the recarburization coefficient of the recarburizers is only related to the stirring argon flow.
3) After slagging, power is off, argon bottom blowing stirring is carried out, a sample is taken for analysis, the analysis result is obtained, the content of the molten steel components is adjusted according to the target component requirement, then argon bottom blowing stirring is carried out, sampling analysis is carried out again until the components of the molten steel meet the target components, and then steel is tapped to obtain the low-carbon steel.
Proper amount of recarburization is carried out on steel in the refining and slagging process by adjusting the dosage of the recarburizing agent and the flow of bottom-blown argon; finally, the amount of recarburization in steel through strong stirring is controlled within the range of 0.01-0.03%, the bottom-blowing argon flow is guaranteed to be 800-1000 NL/min, stirring is carried out for 90-120 seconds, and the recarburization requirement of molten steel can be met through the strong stirring process.
Preferably, the carbon content of the low-carbon steel is less than or equal to 0.25 percent, and the ladle is a double-air-permeable brick ladle with the capacity of 100-120 tons.
Preferably, the alloy and the slag in the step 1) are well known in the art, and more preferably, the alloy comprises one or more of ferromanganese, ferrochrome, ferromolybdenum and ferrosilicon, and the slag comprises lime, pre-melted slag and the like.
Preferably, the flow of the single-way argon in the step 2) is + 10 to 30NL/min, the flow of the soft-blowing argon is generally 15 to 30NL/min, the slight fluctuation of the actual molten steel liquid level is taken as the standard, and the power transmission time is more than or equal to 20 min.
Preferably, in the step 3), after slagging, the control range of the refining slag components is as follows: SiO 22：7～9％，Al2O3: 25-32%, CaO: 45-55%, MgO: 6-8%, and when the temperature of the refining slag is more than or equal to 1500 ℃, the viscosity is less than or equal to 0.4 Pa.S
Preferably, the flow rate of the stirring argon gas in the step 3) is controlled to be 800-1000 NL/min; the stirring time is 90-120 seconds.
Preferably, the specific steps of adjusting the content of the molten steel components according to the target component requirements in the step 3) comprise: adding alloy such as ferromanganese, ferrochromium, ferromolybdenum and the like into steel to adjust the components of the molten steel, then blowing argon at the bottom and stirring, and adding a proper amount of carburant into the steel according to the components of the molten steel during stirring to carburize the molten steel.
During alloying, the addition amount (kg) of carburant per ton of steel is { ([ C% ] into- [ C% ] first) ÷ ([ C% ] in-situ x recovery) } × 1000
[ C% ] into- -the required carbon content of the finished molten steel;
[ C% ] C-carbon content in the existing molten steel;
carbon content in [% C ] - - - - - - - - -carburant; the stirring time is 90-120 seconds.
Compared with the prior art, the invention has the following beneficial effects:
(1) the invention quantifies the using amount of the recarburizer, silicon carbide and other deoxidizing materials and the bottom-blown argon in the refining diffusion deoxidizing process, reduces the influence of human factors, solves the problems of large change of the recarburizer and the silicon carbide in the refining diffusion deoxidizing process of the molten steel and large fluctuation of the molten steel components, and is beneficial to the standardized operation of the molten steel in the refining process.
(2) The invention optimizes the recarburization process of the molten steel, the recarburization agent is used in 2 stages, one is in the diffusion deoxidation stage, the recarburization amount of the recarburization agent and the recarburization agent to the molten steel in the stage is stably controlled by reasonably controlling the flow of bottom-blown argon and the use amounts of the recarburization agent and the silicon carbide, and the other is in the subsequent molten steel alloying stage, and the accurate addition amount of the recarburization agent is calculated according to the difference between the components of the molten steel and the target components. In the first stage, the molten steel carburetion amount in the stage can be adjusted by controlling the flow of bottom-blowing argon, the using amount of the carburetant and the using amount of silicon carbide, so that the molten steel carburetion amount in the second stage is controlled within the range of 0.01-0.03%, and the carburetant can completely enter the molten steel within the specified flow and time of stirring argon. The carburetion effect is ensured, the flow and time of stirring argon are limited, the conditions of molten steel exposure, molten steel inspiration and the like are reduced, and the molten steel quality is ensured.
(3) The addition of the carburant is divided into 2 stages, and in the first stage, when the carburant for diffusion deoxidation is calculated, the refined target carburant is reduced by 0.02 percent, the excessive carbon content of molten steel caused by the fluctuation of the carbon content in the carburant, silicon carbide and alloy is avoided, and a fault-tolerant space is reserved.
Detailed Description
The present invention will be further described with reference to the following specific examples.
Example 1
20CrMnTiH gear steel is smelted by a 120-ton refining furnace, and the steel grade comprises the following components: c: 0.17-0.23%, Mn: 0.80-1.20%, Cr: 1.00-1.45%, Si: 0.17-0.37%, Ti: 0.04-0.10%, and the target components are: c: 0.19%, Mn: 0.88%, Cr: 1.05%, Si: 0.25%, Ti: 0.070%. 120.4 tons of steel are tapped from the primary smelting furnace, the carbon at the end point of the primary smelting furnace is 0.073%, 796kg of silicomanganese alloy, 468kg of medium-carbon ferromanganese, 686kg of high-carbon ferrochrome and 1384kg of medium-carbon ferrochrome are added in the tapping process of the primary smelting furnace, wherein the content of the medium-carbon ferromanganese is 1.56%, the content of the high-carbon ferrochrome is 7.45%, and the content of the medium-carbon ferrochrome is 2.08%. Through calculation, the carburization of the alloy workpiece processed by the primary smelting furnace is 0.071 percent. In the tapping process of the primary smelting furnace, 730kg of lime, 300kg of premelted slag and 180kg of pure aluminum blocks are added into a steel ladle along with the steel flow.
After the molten steel reaches a refining position, firstly carrying out argon re-blowing operation, measuring the temperature of 1516 ℃ after argon re-blowing, then starting power transmission, preliminarily calculating the recarburization amount of a slagging process to be (the recarburization amount of a refining target-the recarburization amount of the electric furnace alloy-0.02%) (0.19% -0.073% -0.071% -0.02%) (0.026%), adjusting the flow of bottom blowing argon to be 35+35NL/min, adding 100kg of lime into a steel ladle in the power transmission process, 100kg of a slag modifier, selecting the recarburization coefficient of silicon carbide to be 0.32, the recarburization coefficient of the recarburization agent to be 0.12, the carbon content of the used silicon carbide to be 25%, the carbon content of the recarburization agent to be 88%, and the silicon carbide to be estimated to be 80kg, wherein the recarburization: adding silicon carbide, the carbon content of silicon carbide, the recarburization coefficient of silicon carbide/molten steel amount/1000, 80, 0.25, 0.32, 120.4, 1000, 100, 0.005%, using the recarburizer in the slagging stage (refining target recarburization amount-electric furnace alloy recarburization amount-0.02% -silicon carbide predicted recarburization amount), the carbon content of the recarburizer, the recarburization coefficient of the recarburization agent x 100, 0.19% -0.073% -0.071% -0.02% -0.005%), 0.88% -0.12, 100, 120.4 and 34kg, ensuring good reducing atmosphere in the furnace, powering off after 25min, stirring at a bottom argon flow rate of 900NL/min for 90 seconds, adjusting argon to be in a soft blowing state, taking a sample to analyze molten steel components, and then continuing to power transmission, wherein the analysis result of the sample is C: 0.159%, Mn: 0.787%, Cr: 0.986%, Si: 0.203%, Ti: 0.005 percent, adding 131kg of high-carbon ferrochrome, 147kg of silicomanganese, ferrotitanium and the like into steel according to the primary sample inspection result to adjust the components of molten steel, wherein the high-carbon ferrochrome is increased by about 0.008 percent, then stirring is started by the bottom blowing argon flow of 800-1000 NL/min, 34.2kg of carburant is added into the steel in the stirring process, the stirring process lasts for 2min, then a secondary sample is taken for analysis, then power transmission and temperature raising are continuously carried out, and the analysis result of the secondary sample is C: 0.185%, Mn: 0.87%, Cr: 1.036%, Si: 0.25%, Ti: 0.075 percent of the molten steel components except carbon are adjusted according to the secondary sample analysis result, and after the temperature of the molten steel reaches 1630 ℃, the molten steel is tapped and enters a VD station after being subjected to slag skimming.
Example 2
A refining furnace of 120 tons is used for smelting 22CrMoH gear steel, and the steel comprises the following components: c: 0.19 to 0.25%, Mn: 0.55-90%, Cr: 0.85 to 1.25%, Si: 0.17 to 0.37%, Mo: 0.35-0.45%, and the target components are: c: 0.22%, Mn: 0.86%, Cr: 1.16%, Si: 0.25%, Mo: 0.39 percent. 118.6 tons of primary furnace steel are discharged, the end point carbon of the primary furnace is 0.083 percent, 787kg of silicomanganese alloy, 474kg of medium carbon ferromanganese, 607kg of high carbon ferrochrome, 1561kg of medium carbon ferrochrome and 594.9kg of ferromolybdenum are added in the primary furnace steel discharge process, wherein the carbon content of the medium carbon ferromanganese is 1.42 percent, the carbon content of the high carbon ferrochrome is 7.34 percent, and the carbon content of the medium carbon ferrochrome is 2.05 percent. Through calculation, the carburization of the alloy processed by the primary smelting furnace is 0.068 percent. In the tapping process of the primary smelting furnace, 713kg of lime, 194kg of pre-melted slag and 208kg of pure aluminum blocks are added into a ladle along with the flow of steel.
After the molten steel reaches a refining position, firstly carrying out argon re-blowing operation, measuring the temperature of 1528 ℃ after argon re-blowing, then starting power transmission, preliminarily calculating the recarburization amount of a slagging process to be (the recarburization amount of a refining target recarburization amount-0.02% of an electric furnace alloy) to be (0.22% -0.083% -0.068% -0.02%) to be 0.049%, adjusting the flow of bottom blowing argon to be 42+ NL 42/min, adding 100kg of lime into a ladle in the power transmission process, 100kg of a slag modifier, selecting the recarburization coefficient of silicon carbide to be 0.42, the recarburization coefficient of the recarburization agent to be 0.09, the carbon content of the used silicon carbide to be 20%, the carbon content of the recarburization agent to be 90%, and predicting to use 90kg of silicon carbide, wherein the recarburization amount: adding silicon carbide, carbon content of silicon carbide, recarburization coefficient of silicon carbide/water content of molten steel/1000, 90, 0.2, 0.42, 118.6, 1000, 100, 0.006%, using amount of recarburizer in a slagging stage (refining target recarburization amount-electric furnace alloy recarburization amount-0.02% -silicon carbide predicted recarburization amount), carbon content of recarburizer, recarburization coefficient of recarburizer x 100, 0.22% -0.083% -0.068% -0.02% -0.006%/0.90%, 0.09, 100, 118.6 and 50kg, ensuring good reducing atmosphere in the furnace, stopping power supply after 27min, stirring bottom blowing argon at 900NL/min for 90 seconds, adjusting argon to a soft blowing state, taking a sample to analyze molten steel components, and then continuing to transmit power, wherein the analysis result of the sample is C: 0.174%, Mn: 0.803%, Cr: 1.097%, Si: 0.153%, Mo: 0.317%, according to the primary sample inspection result, adding 170kg of high-carbon ferrochrome, 75kg of ferrosilicon, 134kg of ferromolybdenum and 120kg of medium-carbon ferromanganese into steel to adjust the components of molten steel, wherein the alloy is carburized by about 0.011%, then starting stirring by using bottom blowing argon flow of 800-1000 NL/min, adding 34kg of carburant into the steel in the stirring process, continuing the stirring process for 2min, then taking a secondary sample for analysis, then continuing transmitting power and raising the temperature, wherein the analysis result of the secondary sample is C: 0.212%, Mn: 0.857%, Cr: 1.136%, Si: 0.221%, Mo: and 0.372 percent of the total carbon content of the molten steel, adjusting the components of the molten steel except carbon according to the analysis result of the secondary sample, measuring the temperature, tapping after the temperature of the molten steel reaches 1628 ℃, slagging off, and then entering a VD station.
Conventional technical knowledge in the art can be used for the details which are not described in the present invention.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (6)
1. An LF refining method of low-carbon steel comprises the following steps:
1) controlling the carbon at the end point of the primary smelting furnace to be 0.07-0.09%, and adding alloy and slag charge into steel along with the flow of the steel in the tapping process of the primary smelting furnace;
2) after the molten steel reaches a refining position, power is supplied, silicon carbide and a carburant are added for diffusion deoxidation, and argon is blown from the bottom of a ladle;
wherein the dosage of the silicon carbide is 70-90 kg/furnace steel,
the predicted recarburization amount of the silicon carbide is the addition amount of the silicon carbide and the carbon content of the silicon carbide and the recarburization coefficient of the silicon carbide/molten steel amount/1000, and the recarburization coefficient of the silicon carbide ranges from 0.03 to 0.1;
the adding amount of carburant for diffusion deoxidation is (the carburant of a refining target-the carburant of an electric furnace alloy-0.02% -the predicted carburant of silicon carbide) ÷ the carburant carbon content multiplied by the carburant coefficient multiplied by 100; the value range of the recarburization coefficient is 0.05-0.15;
3) after slagging, power is off, argon bottom blowing stirring is carried out, a sample is taken for analysis, the analysis result is obtained, the content of the molten steel components is adjusted according to the target component requirement, then argon bottom blowing stirring is carried out, sampling analysis is carried out again until the components of the molten steel meet the target components, and then steel is tapped to obtain the low-carbon steel.
2. The LF refining method as recited in claim 1, wherein the low carbon steel has a carbon content of 0.25% or less, and the ladle is a double air brick ladle with a capacity of 100 and 120 tons.
3. The LF refining method according to claim 1, wherein in the step 2), the argon flow is + soft argon blowing (10-30) NL/min, the argon flow is 15-30 NL/min, and the power transmission time is not less than 20 min.
4. The LF refining method according to claim 1, wherein in the step 3), after slagging, the refining slag component control range is as follows: SiO 22：7～9％，Al2O3: 25-32%, CaO: 45-55%, MgO: 6-8%, and when the temperature of the refining slag is more than or equal to 1500 ℃, the viscosity is less than or equal to 0.4 Pa.S.
5. The LF refining method according to claim 1, wherein the flow rate of argon in the step 3) is controlled to be 800-1000 NL/min; the stirring time is 90-120 seconds.
6. The LF refining method according to claim 1, wherein the specific step of adjusting the content of molten steel components according to the target component requirement in the step 3) comprises: adding alloy into steel to adjust the components of the molten steel, then blowing argon from the bottom and stirring, and adding a carburant into the steel according to the components of the molten steel during stirring to carburize the molten steel.
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| CN115906538A (en) * | 2023-01-09 | 2023-04-04 | 湖南华联云创信息科技有限公司 | Method for predicting molten steel components in ladle refining furnace |
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| CN109988885A (en) * | 2019-05-14 | 2019-07-09 | 鞍钢股份有限公司 | A kind of production method of low-carbon killed steel |
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| CN106399632A (en) * | 2016-09-09 | 2017-02-15 | 武汉钢铁股份有限公司 | High-carbon steel recarburization method |
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