CN102260768A - Static mixing method for steelmaking molten steel - Google Patents
Static mixing method for steelmaking molten steel Download PDFInfo
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- CN102260768A CN102260768A CN 201110218089 CN201110218089A CN102260768A CN 102260768 A CN102260768 A CN 102260768A CN 201110218089 CN201110218089 CN 201110218089 CN 201110218089 A CN201110218089 A CN 201110218089A CN 102260768 A CN102260768 A CN 102260768A
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- steel
- stirring
- molten steel
- refining
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Abstract
The invention discloses a static mixing method for steelmaking molten steel. Steel is made by a process comprising the following steps of: performing the preprocessing of molten iron, smelting in a converter, refining in a low-frequency (LF) furnace, performing relative humidity (RH) refining and performing continuous casting. In the process of the steelmaking, static mixing is performed twice, wherein in the static mixing for the first time, a pure calcium line of between 200 and 350 meters/furnace is fed into the molten steel after the LF processing is finished in the process of refining in the LF furnace to perform the static mixing for 4 to 8 minutes, and during the static mixing, the bottom blowing flow is between 15 and 80 Nm<3>/minute; and in the static mixing for the second time, the calcium line is fed into the molten steel after vacuum processing is finished in the process of the RH refining to perform the static mixing for 6 to 15 minutes, and during the static mixing, the bottom blowing flow is between 10 and 50 Nm<3>/minute. When the static mixing method is adopted, the mass fraction of total oxygen of steel grades is controlled to (5-20)*10<6>, the crack detection yield of rolled steel plates is more than 99 percent, and the control level of impurities is improved obviously.
Description
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Technical field
The present invention relates to a kind of process for making, specifically a kind of quiet method of stirring of molten steel in steel making of in two operations of process for making, carrying out.
Background technology
The steel grade of steel-making aluminium deoxidation generally adopts one refining in the end to finish the quiet then certain hour that stirs of a certain amount of calcium line of feeding in molten steel at present, feed calcium line and be for make in the steel aluminium be inclusion by the solid-state liquid state that becomes, the quiet process of stirring is to grow up and float for the inclusion collision.But there is the dead angle because the vapour pressure of calcium is very big and ladle molten steel flows, cause quiet instability and the ununiformity of stirring back calcium of molten steel like this, add because of rhythm of production causes the quiet time of stirring soon and lack, to have the eliminating of can't floating of the large-scale inclusion of part in the process last quiet stirring, be trapped in cause in the steel roll the back steel plate be mingled with exceed standard with the flaw detection defective, reduced the steel plate recovery rate.
Summary of the invention
Shortcoming at above prior art existence, the quiet method of stirring that the purpose of this invention is to provide a kind of molten steel in steel making, this method carry out in two operations of process for making that molten steel in steel making is quiet to be stirred, and can eliminate the quiet drawback of stirring of old technology, reduce the steel grade inclusion content, improve the molten steel purity.
The objective of the invention is to be achieved through the following technical solutions:
A kind of quiet method of stirring of molten steel in steel making, the technical process of hot metal pretreatment+converter smelting+LF stove refining+RH refining+continuous casting is adopted in steel-making; It is characterized in that: this method adopts twice quiet stirring in the process for making flow process; For the first time quiet LF processing of stirring in LF stove refining procedure finishes back feeding calcium line in molten steel and carries out quiet stirring; For the second time quiet vacuum-treat of stirring in the RH refining procedure finishes back feeding calcium line in molten steel and carries out quiet stirring; Specific requirement is as follows:
1) quiet stirring to for the first time: the LF processing finishes in molten steel the quiet 4～8min that stirs behind 200～350 meters/stove of the pure calcium line of feeding, and the bottom blowing flow set is 15～80Nm during quiet stirring
3/ min;
2) quiet stirring to for the second time: vacuum-treat finishes the quiet 6～15min that stirs in back, and the bottom blowing flow set is 10～50Nm during quiet stirring
3/ min.
Among the present invention, arrive stokehold sulphur≤0.004% after the hot metal pretreatment.Converter smelting endpoint molten steel oxygen level≤1200ppm, tapping process adds 0.5～3 kilogram of/ton steel of aluminium, adds 7～12 kilograms of/ton steel of slag charge.After molten steel arrives the LF stove, add lime, refining slag and slag reductor and make white slag fast, change slag end back refining slag weight percent and form: dual alkalinity CaO/SiO
2Be controlled at 5～10; (TFe+MnO) %≤4%; Al
2O
3% is controlled at 16～29%; Add aluminum shot or feeding aluminum steel in the molten steel and adjust full aluminium content in the molten steel, the LF processing finishes full aluminium content 0.015%～0.040%.
RH vacuum processing time 20～50min, wherein the treatment time of vacuum tightness 50～300Pa is 12～30min, vacuum-treat is not added and is contained aluminium deoxidizer.Casting process adopts the whole process protection cast.
The present invention can be reduced to oxygen level in molten steel and the slag scope at the end at converter tapping, LF refining process mid-early stage adding aluminium content.The LF stove adopts the high Al of high basicity
2O
3Slag, this slag system have lower fusing point and good flowability, like this inclusion in the easier absorption molten steel of operation.Finish to carry out quiet stirring first time after calcium is handled in the LF processing, can make molten steel be arranged the competent sex change time like this, and make inclusion after the sex change in the easier collision of the RH vacuum-treat process come-up of growing up at the inclusion of converter tapping process and LF process deoxidation formation.The RH processing finish the back for the second time quiet stir can further make steel grade not fully the inclusion of sex change carry out denaturing treatment, after RH handles that the back is quiet and stirs for some time, steel grade is removed through the small-particle liquid inclusions come-up that denaturing treatment does not float.Casting process adopts the whole process protection cast, prevents that secondary oxidation of steel from forming new inclusion.
Advantage of the present invention is: adopt the present invention, the massfraction of the total oxygen of steel grade can be controlled to (5～20) * 10 respectively
6The inclusion of steel grade mostly is spherical, the equivalent diameter of inclusion is (1～10) micron, roll back steel plate inspection qualification rate greater than 99%, the grading of category-B inclusion is overall to be reduced, and 1 grade of following ratio accounts for 95%, the Control and Inclusion Removal level obviously improves, significantly reduce the quality problems that cause because of inclusion, the scrap rate that caused because of inclusion in every month is less than 0.5%, and economic benefit obviously improves.
Embodiment
Embodiment 1
A kind of quiet method of stirring of molten steel in steel making, the technical process of employing is: adopt hot metal pretreatment+converter smelting+LF stove refining, quiet stirring+RH refining for the first time, quiet stirring+continuous casting for the second time.Arrive stokehold sulphur 0.004% after the hot metal pretreatment; Converter smelting endpoint molten steel oxygen level 652ppm, tapping process adds 0.5 kilogram of/ton steel of aluminium, adds 7 kilograms of/ton steel of slag charge; After molten steel arrived the LF stove, adding lime, refining slag, slag reductor were made white slag fast, changed slag end back refining slag weight percent and formed: dual alkalinity (CaO)/(SiO
2) be controlled at 5.1; (TFe+MnO) % is controlled at 2.7%; Al
2O
3% is controlled at 16%, adds full aluminium content in aluminum shot or the feeding aluminum steel adjustment molten steel early stage in the molten steel, and the LF processing finishes full aluminium content 0.015%, and the LF processing finishes 200 meters/stove of the back pure calcium line of feeding, the quiet 4min that stirs, and quiet wake turbulence amount is set at 15 Nm
3/ min; RH vacuum processing time 20min, wherein the treatment time of vacuum tightness 100Pa is 12min, and vacuum-treat is not added and is contained aluminium deoxidizer, and line feeding finishes the quiet time 6min that stirs in back, and the bottom blowing flow set is 15Nm during quiet stirring
3/ min; Casting process adopts the whole process protection cast.
Use the quiet method of stirring of the molten steel in steel making of present embodiment, the total oxygen massfraction of steel grade can be controlled to 9 * 10 respectively
6With, the inclusion of steel grade mostly is spherical, the maximum equivalent diameter of inclusion is 9 microns, roll back steel plate inspection qualification rate 100%, the grading of category-B inclusion is overall to be reduced, and 1 grade of following ratio accounts for 98%, and the Control and Inclusion Removal level obviously improves, significantly reduce the quality problems that cause because of inclusion, the scrap rate 0.08% that caused because of inclusion this month.
Embodiment 2
The quiet method of stirring of another molten steel in steel making, the technical process of employing is: adopt hot metal pretreatment+converter smelting+LF stove refining, quiet stirring+RH refining for the first time, quiet stirring+continuous casting for the second time.Arrive stokehold sulphur 0.002% after the hot metal pretreatment; Converter smelting endpoint molten steel oxygen level 760ppm, tapping process adds 1.9 kilograms of/ton steel of aluminium, adds 8.5 kilograms of/ton steel of slag charge; After molten steel arrived the LF stove, adding lime, refining slag, slag reductor were made white slag fast, changed slag end back refining slag weight percent and formed: dual alkalinity (CaO)/(SiO
2) be controlled at 5.9; (TFe+MnO) % is controlled at 2.1%; Al
2O
3% is controlled at 25.6%, adds full aluminium content in aluminum shot or the feeding aluminum steel adjustment molten steel early stage in the molten steel, and the LF processing finishes full aluminium content 0.036%, and the LF processing finishes 280 meters/stove of the back pure calcium line of feeding, the quiet 7min that stirs, and quiet wake turbulence amount is set at 45 Nm
3/ min; RH vacuum processing time 43min, wherein the treatment time of vacuum tightness 150Pa is 13min, and vacuum-treat is not added and is contained aluminium deoxidizer, and line feeding finishes the quiet time 12min that stirs in back, and the bottom blowing flow set is 40Nm during quiet stirring
3/ min; Casting process adopts the whole process protection cast.
Use the quiet method of stirring of molten steel in steel making of the present invention, the massfraction of the total oxygen of steel grade can be controlled to 10 * 10 respectively
66The inclusion of steel grade mostly is spherical, the maximum equivalent diameter of inclusion is 8 microns, roll back steel plate inspection qualification rate greater than 99%, the grading of category-B inclusion is overall to be reduced, and 1 grade of following ratio accounts for 99%, and the Control and Inclusion Removal level obviously improves, significantly reduce the quality problems that cause because of inclusion, the scrap rate 0.11% that caused because of inclusion this month.
Embodiment 3
The quiet method of stirring of another molten steel in steel making, the technical process of employing is: adopt hot metal pretreatment+converter smelting+LF stove refining, quiet stirring+RH refining for the first time, quiet stirring+continuous casting for the second time.Arrive stokehold sulphur 0.003% after the hot metal pretreatment; Converter smelting endpoint molten steel oxygen level 678ppm, tapping process adds 0.95 kilogram of/ton steel of aluminium, adds 8.3 kilograms of/ton steel of slag charge; After molten steel arrived the LF stove, adding lime, refining slag, slag reductor were made white slag fast, changed slag end back refining slag weight percent and formed: dual alkalinity (CaO)/(SiO
2) be controlled at 6.1; (TFe+MnO) % is controlled at 1.9%; Al
2O
3% is controlled at 22%, adds full aluminium content in aluminum shot or the feeding aluminum steel adjustment molten steel early stage in the molten steel, and the LF processing finishes full aluminium content 0.037%, and the LF processing finishes 300 meters/stove of the back pure calcium line of feeding, the quiet 7min that stirs, and quiet wake turbulence amount is set at 48 Nm
3/ min; RH vacuum processing time 42min, wherein the treatment time of vacuum tightness 200Pa is 14min, and vacuum-treat is not added and is contained aluminium deoxidizer, and line feeding finishes the quiet time 18min that stirs in back, and the bottom blowing flow set is 30Nm during quiet stirring
3/ min; Casting process adopts the whole process protection cast.
Use the quiet method of stirring of the molten steel in steel making of present embodiment, the massfraction of total oxygen of steel grade and sulphur can be controlled to 12 * 10 respectively
6The inclusion of steel grade mostly is spherical, the maximum equivalent diameter of inclusion is 7 microns, roll back steel plate inspection qualification rate 100%, the grading of category-B inclusion is overall to be reduced, and 1 grade of following ratio accounts for 100%, and the Control and Inclusion Removal level obviously improves, significantly reduce the quality problems that cause because of inclusion, the scrap rate that caused because of inclusion in every month is less than 0.06%
Embodiment 4
The quiet method of stirring of another molten steel in steel making, the technical process of employing is: hot metal pretreatment+converter smelting+LF stove refining, quiet stirring+RH refining for the first time, quiet the stirring of second hyposynchronization+continuous casting arrive stokehold sulphur 0.002% after the hot metal pretreatment; Converter smelting endpoint molten steel oxygen level 1200ppm, tapping process adds 3 kilograms of/ton steel of aluminium, adds 12 kilograms of/ton steel of slag charge; After molten steel arrived the LF stove, adding lime, refining slag, slag reductor were made white slag fast, changed slag end back refining slag weight percent and formed: dual alkalinity (CaO)/(SiO
2) be controlled at 10; (TFe+MnO) % is controlled at 1.2%; Al
2O
3% is controlled at 29, adds full aluminium content in aluminum shot or the feeding aluminum steel adjustment molten steel early stage in the molten steel, and the LF processing finishes full aluminium content 0.040%, and the LF processing finishes 350 meters/stove of the back pure calcium line of feeding, the quiet 8min that stirs, and quiet wake turbulence amount is set at 80 Nm
3/ min; RH vacuum processing time 50min, wherein the treatment time of vacuum tightness 300Pa is 30min, and vacuum-treat is not added and is contained aluminium deoxidizer, and vacuum-treat finishes the quiet time 15min that stirs in back, and the bottom blowing flow set is 50Nm during quiet stirring
3/ min; Casting process adopts the whole process protection cast.
Use the quiet method of stirring of the molten steel in steel making of present embodiment, the massfraction of the total oxygen of steel grade can be controlled to 13 * 10 respectively
6The inclusion of steel grade mostly is spherical, the maximum equivalent diameter of inclusion is 10 microns, roll back steel plate inspection qualification rate greater than 99%, the grading of category-B inclusion is overall to be reduced, and 1 grade of following ratio accounts for 99%, and the Control and Inclusion Removal level obviously improves, significantly reduce the quality problems that cause because of inclusion, the of that month scrap rate that causes because of inclusion is less than 0.11%.
Claims (6)
1. the quiet method of stirring of a molten steel in steel making, the technical process of hot metal pretreatment+converter smelting+LF stove refining+RH refining+continuous casting is adopted in steel-making; It is characterized in that: this method adopts twice quiet stirring in the process for making flow process; For the first time quiet LF processing of stirring in LF stove refining procedure finishes back feeding calcium line in molten steel and carries out quiet stirring; For the second time quiet vacuum-treat of stirring in the RH refining procedure finishes back feeding calcium line in molten steel and carries out quiet stirring; Specific requirement is as follows:
1) quiet stirring to for the first time: the LF processing finishes in molten steel the quiet 4～8min that stirs behind 200～350 meters/stove of the pure calcium line of feeding, and the bottom blowing flow set is 15～80Nm during quiet stirring
3/ min;
2) quiet stirring to for the second time: vacuum-treat finishes the quiet 6～15min that stirs in back, and the bottom blowing flow set is 10～50Nm during quiet stirring
3/ min.
2. the quiet method of stirring of molten steel in steel making according to claim 1 is characterized in that: arrive stokehold sulphur≤0.004% after the hot metal pretreatment.
3. the quiet method of stirring of molten steel in steel making according to claim 1 is characterized in that: converter smelting endpoint molten steel oxygen level≤1200ppm, 0.5～3 kilogram of/ton steel of tapping process adding aluminium, 7～12 kilograms of/ton steel of adding slag charge.
4. the quiet method of stirring of molten steel in steel making according to claim 1 is characterized in that: after molten steel arrives the LF stove, add lime, refining slag and slag reductor and make white slag fast, change slag end back refining slag weight percent and form: dual alkalinity CaO/SiO
2Be controlled at 5～10; (TFe+MnO) %≤4%; Al
2O
3% is controlled at 16～29%; Add aluminum shot or feeding aluminum steel in the molten steel and adjust full aluminium content in the molten steel, the LF processing finishes full aluminium content 0.015%～0.040%.
5. the quiet method of stirring of molten steel in steel making according to claim 1 is characterized in that: RH vacuum processing time 20～50min, and wherein the treatment time of vacuum tightness 50～300Pa is 12～30min, vacuum-treat is not added and is contained aluminium deoxidizer.
6. the quiet method of stirring of molten steel in steel making according to claim 1 is characterized in that: the cast of casting process employing whole process protection.
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|---|---|---|---|
| CN 201110218089 CN102260768A (en) | 2011-08-01 | 2011-08-01 | Static mixing method for steelmaking molten steel |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110218089 CN102260768A (en) | 2011-08-01 | 2011-08-01 | Static mixing method for steelmaking molten steel |
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ID=45007601
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106544469A (en) * | 2016-11-25 | 2017-03-29 | 芜湖新兴铸管有限责任公司 | The method for reducing the D type impurities in steel-making |
| CN106702083A (en) * | 2015-11-17 | 2017-05-24 | 鞍钢股份有限公司 | Control method for B-type inclusions in high-grade steel |
| CN109797262A (en) * | 2019-01-03 | 2019-05-24 | 南京钢铁股份有限公司 | A kind of production method removing abrasion-resistant stee non-metallic inclusion |
| CN111272311A (en) * | 2020-02-04 | 2020-06-12 | 中冶赛迪工程技术股份有限公司 | Temperature measurement sampling robot process arrangement and operation flow for steel-making production refining treatment |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101691642A (en) * | 2009-10-20 | 2010-04-07 | 南京钢铁股份有限公司 | Sulfuric acid dew point corrosion-resistant steel and production process thereof |
| CN101921892A (en) * | 2010-09-02 | 2010-12-22 | 南京钢铁股份有限公司 | Calcium treatment method for molten steel in steelmaking |
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2011
- 2011-08-01 CN CN 201110218089 patent/CN102260768A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101691642A (en) * | 2009-10-20 | 2010-04-07 | 南京钢铁股份有限公司 | Sulfuric acid dew point corrosion-resistant steel and production process thereof |
| CN101921892A (en) * | 2010-09-02 | 2010-12-22 | 南京钢铁股份有限公司 | Calcium treatment method for molten steel in steelmaking |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106702083A (en) * | 2015-11-17 | 2017-05-24 | 鞍钢股份有限公司 | Control method for B-type inclusions in high-grade steel |
| CN106702083B (en) * | 2015-11-17 | 2018-06-26 | 鞍钢股份有限公司 | A kind of high-grade steel B type impurity control methods |
| CN106544469A (en) * | 2016-11-25 | 2017-03-29 | 芜湖新兴铸管有限责任公司 | The method for reducing the D type impurities in steel-making |
| CN109797262A (en) * | 2019-01-03 | 2019-05-24 | 南京钢铁股份有限公司 | A kind of production method removing abrasion-resistant stee non-metallic inclusion |
| CN111272311A (en) * | 2020-02-04 | 2020-06-12 | 中冶赛迪工程技术股份有限公司 | Temperature measurement sampling robot process arrangement and operation flow for steel-making production refining treatment |
| CN111272311B (en) * | 2020-02-04 | 2022-02-18 | 中冶赛迪工程技术股份有限公司 | Temperature measurement sampling robot process arrangement and operation flow for steel-making production refining treatment |
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Application publication date: 20111130 |