CN117210642A - Method for reducing proportion of alumina in U71Mn inclusion by utilizing rare earth - Google Patents
Method for reducing proportion of alumina in U71Mn inclusion by utilizing rare earth Download PDFInfo
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- CN117210642A CN117210642A CN202311078619.XA CN202311078619A CN117210642A CN 117210642 A CN117210642 A CN 117210642A CN 202311078619 A CN202311078619 A CN 202311078619A CN 117210642 A CN117210642 A CN 117210642A
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- rare earth
- u71mn
- equal
- slag
- alumina
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- 238000000034 method Methods 0.000 title claims abstract description 77
- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 51
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 42
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 title claims abstract description 20
- 239000002893 slag Substances 0.000 claims abstract description 43
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 42
- 239000010959 steel Substances 0.000 claims abstract description 42
- 238000007670 refining Methods 0.000 claims abstract description 33
- 239000000956 alloy Substances 0.000 claims abstract description 28
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 28
- 238000003723 Smelting Methods 0.000 claims abstract description 15
- 238000004519 manufacturing process Methods 0.000 claims abstract description 12
- 230000008569 process Effects 0.000 claims description 53
- 238000010079 rubber tapping Methods 0.000 claims description 30
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 24
- 238000009749 continuous casting Methods 0.000 claims description 22
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 12
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 12
- 229910052786 argon Inorganic materials 0.000 claims description 12
- 238000005266 casting Methods 0.000 claims description 12
- 239000004571 lime Substances 0.000 claims description 12
- 238000007664 blowing Methods 0.000 claims description 7
- 238000009489 vacuum treatment Methods 0.000 claims description 7
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 6
- 239000003795 chemical substances by application Substances 0.000 claims description 6
- 238000006477 desulfuration reaction Methods 0.000 claims description 6
- 230000023556 desulfurization Effects 0.000 claims description 6
- 239000010436 fluorite Substances 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 238000005516 engineering process Methods 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 5
- 229910052782 aluminium Inorganic materials 0.000 abstract description 5
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 abstract description 3
- -1 magnesium aluminate Chemical class 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 229910052596 spinel Inorganic materials 0.000 description 2
- 239000011029 spinel Substances 0.000 description 2
- 150000004645 aluminates Chemical class 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Classifications
-
- 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
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a method for reducing alumina proportion in U71Mn inclusion by utilizing rare earth, which comprises the step of adding 1-4kg/t of rare earth alloy into molten steel after a steel ladle reaches a VD/RH vacuum refining station in a U71Mn steel rail smelting production process, wherein the rare earth element content in the rare earth alloy is 20-50%. The method can effectively reduce the total aluminum content in the U71Mn steel, and further reduce the aluminum oxide content in slag inclusion by more than 10%.
Description
Technical Field
The invention belongs to the technical field of application of rare earth in steel materials, and particularly relates to a method for reducing the proportion of alumina in U71Mn inclusion by using rare earth.
Background
The U71Mn steel rail is a heavy-duty steel rail commonly used at home and abroad, is produced by adopting an aluminum-free deoxidization process, and is refined by adopting low-alkalinity slag in the smelting process. Because of unavoidable entrainment of aluminum and aluminum oxides into the steel in the alloy and slag, slag inclusions or magnesium aluminate spinel inclusions are present in the U71Mn rail, resulting in reduced internal quality of the U71Mn heavy rail. The purchase of high-quality alloy and slag is one of methods for avoiding the generation of slag type inclusions or magnesia-alumina spinel inclusions, but the production cost is greatly increased, so the method for effectively reducing the proportion of alumina in U71Mn inclusions has great significance for reducing the cost and enhancing the efficiency.
Disclosure of Invention
Aiming at one or more problems in the prior art, the invention provides a method for reducing the proportion of alumina in U71Mn inclusion by utilizing rare earth, which comprises the steps of adding 1-4kg/t of rare earth alloy into molten steel after a steel ladle reaches a VD/RH vacuum refining station in a U71Mn steel rail smelting production process, wherein the content of rare earth elements in the rare earth alloy is 20% -50%; and is also provided with
After rare earth alloy is added, vacuum refining operation is started after the steel ladle is kept stand for 5min, the deep vacuum treatment time is more than or equal to 18min, the deep vacuum degree is less than or equal to 20Pa, and the soft blowing time after breaking is more than or equal to 22min.
In some embodiments, the U71Mn rail smelting process comprises: converter-LF external refining-VD/RH vacuum refining-bloom continuous casting.
In some embodiments, the converter technology adopts top-bottom combined blown converter smelting, molten iron is required to be subjected to pretreatment desulfurization, the converter endpoint [ O ] is not more than 400ppm, the [ C ] is not less than 0.10%, the tapping temperature is not less than 1570 ℃, slag is required to be blocked in the tapping process, and the thickness of ladle slag after tapping is not more than 50mm; the tapping process adopts an aluminum-free deoxidizing process, and the addition amount of deoxidizing agent is less than or equal to 4kg/t; adding 3-4kg/t of top slag lime in the tapping process.
In some embodiments, in the LF external refining process, LF refining in place heats white slag, adding slag includes: 3-4kg/t of lime and 0.5-1.5kg/t of fluorite; argon is blown and stirred in the whole refining process, and the flow rate of the argon is more than or equal to 300NL/min.
In some embodiments, in the bloom continuous casting process, the standing time before ladle casting is larger than or equal to 15min, the continuous casting process adopts protection casting, and the continuous casting bloom is produced by adopting the specification of 280mm multiplied by 380 mm.
The method for reducing the alumina proportion in the U71Mn inclusion by utilizing the rare earth based on the technical scheme mainly comprises the steps of adding 1-4kg/t of rare earth alloy into molten steel after a ladle reaches a VD/RH vacuum refining station, wherein the content of rare earth elements in the rare earth alloy is 20% -50%; and after rare earth alloy is added, the ladle is kept stand for 5min, then vacuum refining operation is started, the deep vacuum treatment time is more than or equal to 18min, the deep vacuum degree is less than or equal to 20Pa, and the soft blowing time after breaking is more than or equal to 22min. The method provided by the invention can utilize the added rare earth alloy to deoxidize, which can effectively reduce the oxygen content in molten steel and refined slag, and the rare earth compound produced by deoxidization and Al in slag 2 O 3 The stable rare earth aluminate compound is formed by combination, so that the activity of alumina in slag is reduced, the transfer of aluminum and oxygen at the interface of slag and steel is reduced, the stability of refined slag is improved, and the removal of aluminate inclusion in steel is promoted. The actual production situation shows that after the method is adopted, the total aluminum content in the produced U71Mn steel is obviously reduced, and the proportion of aluminum oxide in slag inclusions is reduced by more than 10 percent. On the other hand, the method provided by the invention does not change the technological process and the steel grade components of the U71Mn steel grade, does not influence the continuous casting property of continuous casting, has the cost of rare earth alloy of about 30 yuan/t, reduces the total aluminum content in the U71Mn steel, reduces the proportion of aluminum oxide in slag inclusion by more than 10%, can effectively improve the overall quality of the steel grade, and can realize the reduction of more than about 80 ten thousand yuan/year.
Detailed Description
The invention aims to provide a method for reducing the proportion of alumina in U71Mn inclusion by utilizing rare earth.
The following describes the invention in detail by way of specific examples, which are intended to aid in understanding the invention and are not intended to limit the invention.
Example 1: method for reducing proportion of alumina in U71Mn inclusion by utilizing rare earth
In this example 1, the smelting production process of U71Mn includes: converter-LF external refining-VD/RH vacuum refining-bloom continuous casting; wherein:
1) In the converter process, a top-bottom combined blown converter is adopted for smelting, molten iron is required to be subjected to pretreatment and desulfurization, the endpoint [ O ] of the converter is less than or equal to 400ppm, the endpoint [ C ] of the converter is more than or equal to 0.10%, the tapping temperature is 1571 ℃, slag is required to be blocked in the tapping process, and the thickness of ladle slag after tapping is less than or equal to 50mm; the tapping process adopts an aluminum-free deoxidizing process, and the addition amount of deoxidizing agent is 4kg/t; adding 3.5kg/t of top slag lime in the tapping process;
2) In the LF external refining process, LF refining in place heats white slag, and adding slag comprises the following steps: 3.5kg/t of lime and 1.0kg/t of fluorite; argon is blown into and stirred in the whole refining process, and the argon flow is 300NL/min;
3) After the ladle reaches the VD/RH vacuum refining station, adding 1kg/t of rare earth alloy, wherein the content of rare earth elements in the rare earth alloy is 20% -50%, the rare earth alloy is contained by a steel drum, and the wall thickness of the drum is more than or equal to 3mm;
4) After rare earth alloy is added, the ladle is kept stand for 5min, then vacuum refining operation is started, the deep vacuum treatment time is 18min, the deep vacuum degree is 20Pa, and the soft blowing time is 22min after the breaking of the air;
5) The steel ladle is kept stand for 15min before casting, protection casting is adopted in the continuous casting process, and the continuous casting billet is produced in the specification of 280mm multiplied by 380 mm.
The content of B-type inclusions (alumina) in the U71Mn steel rail produced in the example 1 is detected according to the method for measuring the content of nonmetallic inclusions in GBT10516-2005 steel, and the content of B-type inclusions in the U71Mn steel rail produced by the existing production process (without adding rare earth alloy) is reduced by more than 10 percent.
Example 2: method for reducing proportion of alumina in U71Mn inclusion by utilizing rare earth
In this example 2, the smelting production process of U71Mn includes: converter-LF external refining-VD/RH vacuum refining-bloom continuous casting; wherein:
1) In the converter process, a top-bottom combined blown converter is adopted for smelting, molten iron is required to be subjected to pretreatment and desulfurization, the endpoint [ O ] of the converter is less than or equal to 400ppm, the endpoint [ C ] of the converter is more than or equal to 0.10%, the tapping temperature is 1570 ℃, slag is required to be blocked in the tapping process, and the thickness of ladle slag after tapping is less than or equal to 50mm; the tapping process adopts an aluminum-free deoxidizing process, and the addition amount of deoxidizing agent is 4kg/t; adding 3.5kg/t of top slag lime in the tapping process;
2) In the LF external refining process, LF refining in place heats white slag, and adding slag comprises the following steps: 3.5kg/t of lime and 1.0kg/t of fluorite; argon is blown into and stirred in the whole refining process, and the argon flow is 300NL/min;
3) After the ladle reaches the VD/RH vacuum refining station, adding 2.5kg/t of rare earth alloy, wherein the content of rare earth elements in the rare earth alloy is 20% -50%, the rare earth alloy is contained by a steel drum, and the wall thickness of the drum is more than or equal to 3mm;
4) After rare earth alloy is added, the ladle is kept stand for 5min, then vacuum refining operation is started, the deep vacuum treatment time is 18min, the deep vacuum degree is 20Pa, and the soft blowing time is 22min after the breaking of the air;
5) The steel ladle is kept stand for 15min before casting, protection casting is adopted in the continuous casting process, and the continuous casting billet is produced in the specification of 280mm multiplied by 380 mm.
The content of B-type inclusions in the U71Mn steel rail produced in the example 2 is detected by a method for measuring the content of nonmetallic inclusions in GBT10516-2005 steel, and the content of B-type inclusions in the U71Mn steel rail produced by the existing production process is reduced by more than 10 percent.
Example 3: method for reducing proportion of alumina in U71Mn inclusion by utilizing rare earth
In this example 3, the smelting production process of U71Mn includes: converter-LF external refining-VD/RH vacuum refining-bloom continuous casting; wherein:
1) In the converter process, a top-bottom combined blown converter is adopted for smelting, molten iron is required to be subjected to pretreatment and desulfurization, the endpoint [ O ] of the converter is less than or equal to 400ppm, the endpoint [ C ] of the converter is more than or equal to 0.10%, the tapping temperature is 1572 ℃, slag is required to be blocked in the tapping process, and the thickness of ladle slag after tapping is less than or equal to 50mm; the tapping process adopts an aluminum-free deoxidizing process, and the addition amount of deoxidizing agent is 4kg/t; adding 3.5kg/t of top slag lime in the tapping process;
2) In the LF external refining process, LF refining in place heats white slag, and adding slag comprises the following steps: 3.5kg/t of lime and 1.0kg/t of fluorite; argon is blown into and stirred in the whole refining process, and the argon flow is 300NL/min;
3) After the ladle reaches the VD/RH vacuum refining station, adding 4kg/t of rare earth alloy, wherein the content of rare earth elements in the rare earth alloy is 20% -50%, the rare earth alloy is contained by a steel drum, and the wall thickness of the drum is more than or equal to 3mm;
4) After rare earth alloy is added, the ladle is kept stand for 5min, then vacuum refining operation is started, the deep vacuum treatment time is 18min, the deep vacuum degree is 20Pa, and the soft blowing time is 22min after the breaking of the air;
5) The steel ladle is kept stand for 15min before casting, protection casting is adopted in the continuous casting process, and the continuous casting billet is produced in the specification of 280mm multiplied by 380 mm.
According to the method for measuring the content of nonmetallic inclusion in GBT10516-2005 steel, the content of B-type inclusion in the U71Mn steel rail produced in the example 3 is detected to be reduced by more than 10 percent compared with the content of B-type inclusion in the U71Mn steel rail produced by the existing production process.
The existing production process for producing U71Mn steel rail mentioned in examples 1-3 above comprises: converter-LF external refining-VD/RH vacuum refining-bloom continuous casting; wherein:
1) In the converter process, a top-bottom combined blown converter is adopted for smelting, molten iron is required to be subjected to pretreatment and desulfurization, the endpoint [ O ] of the converter is less than or equal to 400ppm, the endpoint [ C ] of the converter is more than or equal to 0.10%, the tapping temperature is 1565 ℃, slag is required to be blocked in the tapping process, and the thickness of ladle slag after tapping is less than or equal to 50mm; the tapping process adopts an aluminum-free deoxidizing process, and the addition amount of deoxidizing agent is 4kg/t; adding 3.5kg/t of top slag lime in the tapping process;
2) In the LF external refining process, LF refining in place heats white slag, and adding slag comprises the following steps: 3.5kg/t of lime and 1.0kg/t of fluorite; argon is blown into and stirred in the whole refining process, and the argon flow is 300NL/min;
3) After the ladle reaches the VD/RH vacuum refining station, starting vacuum refining operation, wherein the deep vacuum treatment time is 15min, the deep vacuum degree is 20Pa, and the soft blowing time is 20min after the breaking;
4) The steel ladle is kept stand for 15min before casting, protection casting is adopted in the continuous casting process, and the continuous casting billet is produced in the specification of 280mm multiplied by 380 mm.
Finally, it should be noted that: the foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the technical solutions described in the foregoing embodiments, or that equivalents may be substituted for part of the technical features thereof. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. A method for reducing alumina proportion in U71Mn inclusion by utilizing rare earth comprises adding 1-4kg/t of rare earth alloy into molten steel after a steel ladle reaches a VD/RH vacuum refining station in a U71Mn steel rail smelting production process, wherein the rare earth element content in the rare earth alloy is 20% -50%; and is also provided with
After rare earth alloy is added, vacuum refining operation is started after the steel ladle is kept stand for 5min, the deep vacuum treatment time is more than or equal to 18min, the deep vacuum degree is less than or equal to 20Pa, and the soft blowing time after breaking is more than or equal to 22min.
2. The method for reducing the proportion of alumina in U71Mn inclusion by rare earth according to claim 1, wherein the U71Mn rail smelting process comprises: converter-LF external refining-VD/RH vacuum refining-bloom continuous casting.
3. The method for reducing the proportion of alumina in U71Mn inclusion by utilizing rare earth according to claim 2, wherein the converter technology adopts top-bottom combined blown converter smelting, molten iron is required to be subjected to pretreatment desulfurization, the converter endpoint [ O ] < 400ppm, [ C ] < 0.10%, the tapping temperature is more than or equal to 1570 ℃, slag is required to be blocked in the tapping process, and the thickness of ladle slag after tapping is less than or equal to 50mm; the tapping process adopts an aluminum-free deoxidizing process, and the addition amount of deoxidizing agent is less than or equal to 4kg/t; adding 3-4kg/t of top slag lime in the tapping process.
4. A method of reducing the proportion of alumina in U71Mn inclusions using rare earth according to claim 2 or 3, wherein in the LF external refining process, the LF refining heats the white slag in place, adding slag comprises: 3-4kg/t of lime and 0.5-1.5kg/t of fluorite; argon is blown and stirred in the whole refining process, and the flow rate of the argon is more than or equal to 300NL/min.
5. The method for reducing the proportion of alumina in U71Mn inclusion by using rare earth according to any one of claims 2 to 4, wherein the standing time before ladle casting is not less than 15min in the bloom continuous casting process, the continuous casting process adopts protection casting, and the continuous casting bloom is produced by adopting the specification of 280mm x 380 mm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311078619.XA CN117210642A (en) | 2023-08-25 | 2023-08-25 | Method for reducing proportion of alumina in U71Mn inclusion by utilizing rare earth |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311078619.XA CN117210642A (en) | 2023-08-25 | 2023-08-25 | Method for reducing proportion of alumina in U71Mn inclusion by utilizing rare earth |
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| Publication Number | Publication Date |
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| CN202311078619.XA Pending CN117210642A (en) | 2023-08-25 | 2023-08-25 | Method for reducing proportion of alumina in U71Mn inclusion by utilizing rare earth |
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- 2023-08-25 CN CN202311078619.XA patent/CN117210642A/en active Pending
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