CN102978332A - Smelting method of 9Ni steel - Google Patents

Smelting method of 9Ni steel Download PDF

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Publication number
CN102978332A
CN102978332A CN201210575869XA CN201210575869A CN102978332A CN 102978332 A CN102978332 A CN 102978332A CN 201210575869X A CN201210575869X A CN 201210575869XA CN 201210575869 A CN201210575869 A CN 201210575869A CN 102978332 A CN102978332 A CN 102978332A
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China
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content
controlled
ladle
steel
dephosphorization
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CN201210575869XA
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Chinese (zh)
Inventor
吕延春
王文军
朱国森
朱志远
王浩然
姜中行
刘洋
史志强
王星
孙硕猛
张建师
李铁
崔小勇
柴玉国
张翔
秦登平
张海华
王海宝
张振江
马长文
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Shougang Corp
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Shougang Corp
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Priority to CN201210575869XA priority Critical patent/CN102978332A/en
Publication of CN102978332A publication Critical patent/CN102978332A/en
Pending legal-status Critical Current

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Abstract

The invention relates to a smelting method of 9Ni steel, belonging to the technical field of converting. The method comprises the following steps: molten iron desulfurization pretreatment: the sulfur content of the molten iron is controlled at less than or equal to 0.003 wt%; converter smelting: the final temperature of the converter is controlled at 1600-1670 DEG C; external oxidation and dephosphorization: after tapping, dephosphorization is carried out by using the oxidizing atmosphere, wherein the phosphorus content of the molten steel is controlled at less than or equal to 0.0040 wt%; ladle slag discharge: the ladle is sent into an LF (ladle furnace) to carry out heating treatment, and furnace slag in the ladle is discharged to prevent rephosphoration after desulfurization; LF refinement: deoxidation and desulfurization are carried out to control the sulfur content at less than or equal to 0.0020 wt%; RH refinement: the H content is controlled at less than or equal to 0.0003 wt%; and casting. The invention has the following advantages: the load of the converter is low, and stable control can be implemented only by controlling the phosphorus content at less than 0.0060 wt%.

Description

A kind of 9Ni smelting steel method
Technical field
The invention belongs to the converter steeling technology field.Be particularly related to a kind of 9 Ni smelting steel methods.
Background technology
9Ni steel main application is the low-temperature (low temperature) vessel steel, and they are under-196 ℃ of temperature, and the transverse impact merit reaches 80J, and the impact of collision merit requires to reach 100J.Therefore this steel grade requires phosphorus content extremely low, and finished product phosphorus content requirement≤40ppm prevents the cold short generation of steel, and has increased a large amount of Ni elements, and Ni content is higher than 8%, to increase the impelling strength under its cold condition.
This steel grade finished product carbon content requires to be controlled at≤and 0.050%, phosphorus content is controlled at≤0.0030%, and sulphur content requires to be controlled at≤and 0.0020%, H content requirement≤3ppm, N content is controlled at≤45ppm.By above composition as can be known, it is very big that it smelts difficulty.
The patent No. provides a kind of 9Ni smelting steel method for the patent of " 201110096388.6 ", and body characteristics is to adopt converter duplex technique to carry out dephosphorization treatment; Because many steel mills do not possess the condition that converter duplex is smelted, so there is limitation in the versatility of this patent.
The patent No. is the smelting process of " 200710139497.5 ", its method is dephosphorization, desiliconization and desophorization for hot metal technique, before entering converter, molten iron in hot metal ladle, carries out desiliconization, dephosphorization, desulfurization, its problem is that the desiliconization process quantity of slag is large, in addition owing to the reason of desiliconization, the converter heat loses in a large number, is unfavorable for later process.
Owing to above reason, invented a kind of smelting process of 9Ni steel, the method highly versatile does not use any special equipment, the Composition Control good stability.
Summary of the invention
The object of the present invention is to provide a kind of 9Ni smelting steel method.Solved the problem of the bad stable control of composition in the smelting process.
It smelts step: desulfurizing iron pre-treatment (desulfurization)-converter smelting (dephosphorization, decarburization, alloying)-stove external oxidation dephosphorization (dephosphorization)-ladle deslagging-LF refining (dark desulfurization)-RH refining (degassed)-casting;
The control of concrete technology parameter is as follows:
1) desulfurizing iron pre-treatment: molten steel sulfur content is controlled at≤0.003wt%;
2) converter smelting: the two slags of converter or single slag melting, converter terminal phosphorus content be controlled at≤0.006wt%, sulphur content be controlled at≤and 0.010wt%, carbon content control be controlled between the 8.0%-9.9wt% at≤0.035wt%, Ni content; The converter terminal temperature is controlled between 1600 ℃ ~ 1670 ℃;
3) stove external oxidation dephosphorization: utilize the oxidizing atmosphere dephosphorization after the tapping, the molten steel phosphorus content is controlled at≤0.0040wt%, add the oxidisability slag charge, its main component mass percent is: CaO between 50% ~ 70%, FeO between 15% ~ 35%, Fe 2O 3Between 5% ~ 15%, CaF 2Between 2% ~ 10%;
4) ladle deslagging: behind the dephosphorization, according to temperature regime, ladle is entered the LF stove carry out hyperthermic treatment, then slag in the ladle is got rid of, prevent rephosphorization after the desulfurization; At first molten steel is heated up at the LF stove, during temperature to 1630 ℃ ~ 1650 ℃, ladle handling to deslagging position is mentioned, the below prepares to be subjected to the steel ladle, pulls open lower mouth of a river push-pull valve, molten steel is injected be subjected to the steel ladle, treat to close push-pull valve before molten steel goes out only, the top slag is stayed in the ladle.Be subjected to prepare the wash heat slag charge in the steel ladle and contain the Al reductor, CaO content 〉=85% in the wash heat slag charge, all the other content are CaF 2And other inevitable impurity element.
5) LF refining: deoxidation, desulfurization are controlled at sulphur content≤0.0020wt%;
6) RH refining: H content is controlled at≤0.0003wt%; Then cast.
The invention has the advantages that:
1, the converter burden is little, and phosphorus content gets final product below being controlled at 0.0060wt%, can realize stable control;
2, stove external oxidation dephosphorization effect is good, and phosphorus content can be stablized and is controlled at below the 0.0030wt% behind the dephosphorization;
3, carry out deoxidation, not rephosphorization of sweetening process behind the deslagging;
4, can realize that the finished product phosphorus content is stable is controlled at below the 0.0030wt%;
5, whole process does not all adopt specific installation, and the technique suitability is extremely strong.
Embodiment
Smelting is take 100 tons of converters as example, smelting mode with continuous 2 stoves is carried out, and smelts step to be: desulfurizing iron pre-treatment (desulfurization)-converter smelting (dephosphorization, decarburization, alloying)-stove external oxidation dephosphorization (dephosphorization)-ladle deslagging-LF refining (dark desulfurization)-RH refining (degassed)-casting;
Embodiment 1
The desulfurizing iron pre-treatment adopts the granular magnesium injection method to carry out, the processing of skimming after complete of jetting, and the desulfurized molten iron sulphur content is less than or equal to 0.003wt%.
Converter adopts double slag process to smelt, Ni plate add-on is 10 tons, 103 tons of control taps, 11 tons of adding amount of scrap steel, the deslagging time is 5 minutes and 21 seconds to two slags for the first time, temperature is 1347 ℃, the total add-on ton of lime steel 63.7kg, the converter terminal phosphorus content is 0.006wt%, carbon content is 0.032wt%, temperature is 1638 ℃, and Ni content is 9.6wt%.
Do not carry out deoxidation after the tapping, slag system dephosphorization under oxidizing atmosphereLin Fenpeibi, CaO content 55wt%, FeO content 28wt%, Fe in the slag charge 2O 3Content 12wt%, CaF 2Content 5wt%, behind the stove external oxidation dephosphorization in the molten steel phosphorus content be 0.003wt%.
Molten steel behind the dephosphorization is sent into the LF stove heat up, temperature is controlled to 1653 ℃, slings after ladle is transported to the deslagging position, and the below is put and is subjected to the steel ladle, prepares wash heat material 300kg in the bag, and CaO content is 90wt%, CaF 2Content 10wt% puts into Al grain 220kg deoxidation before wrapping inherent deslagging.
Behind the deslagging, ladle winches to LF deoxidation, desulfurization, and it is 0.001wt6% that desulfurization finishes sulphur content, 1630 ℃ of out-station temperatures, process Si, Mn alloying, smelting process: the dark desulfurization of bottom blowing strong mixing in early stage; Aluminium content 0.070wt% in the refining steel in early stage; Refining process white slag time 25min.Synthetic slag add-on 800~1000kg; LF stove refining cycle 45min.
Enter the degassed processing of RH, vacuum processing time 16min, dark vacuum-treat vacuum tightness≤10mbar; Before the bull ladle molten steel is carried out soft blow, the soft blow argon flow amount is controlled at 60-150NL/min, control soft blow time 10min; The calm time 5min-8min of molten steel after the soft blow.RH cycle 45min.
Finishing H content is 1.2ppm, after be transported to continuous caster and cast.
Embodiment 2
The desulfurizing iron pre-treatment adopts the granular magnesium injection method to carry out, the processing of skimming after complete of jetting, and the desulfurized molten iron sulphur content is less than or equal to 0.003wt%.
Converter adopts single slag process to smelt, and Ni plate add-on is 10 tons, 103 tons of control taps, 10 tons of adding amount of scrap steel, the total add-on ton of lime steel 71.2kg, the converter terminal phosphorus content is 0.005wt%, carbon content is 0.035wt%, and temperature is 1643 ℃, and Ni content is 9.2wt%.
Do not carry out deoxidation after the tapping, slag system dephosphorization under oxidizing atmosphereLin Fenpeibi, CaO content 53wt%, FeO content 23wt%, Fe in the slag charge 2O 3Content 17wt%, CaF 2Content 7wt%, behind the stove external oxidation dephosphorization in the molten steel phosphorus content be 0.003wt%.
Molten steel behind the dephosphorization is sent into the LF stove heat up, temperature is controlled to 1662 ℃, slings after ladle is transported to the deslagging position, and the below is put and is subjected to the steel ladle, prepares wash heat material 300kg in the bag, and CaO content is 90wt%, CaF 2Content 10wt% puts into Al grain 220kg deoxidation before wrapping inherent deslagging.
Behind the deslagging, ladle winches to LF deoxidation, desulfurization, and it is 0.0013wt% that desulfurization finishes sulphur content, 1630 ℃ of out-station temperatures, process Si, Mn alloying.
Enter the degassed processing of RH, finishing H content is 1.1ppm, after be transported to continuous caster and cast.

Claims (3)

1. 9Ni smelting steel method is characterized in that the technical parameter of processing step and control is as follows:
1) desulfurizing iron pre-treatment: molten steel sulfur content is controlled at≤0.003wt%;
2) converter smelting: the two slags of converter or single slag melting, converter terminal phosphorus content be controlled at≤0.006wt%, sulphur content be controlled at≤and 0.010wt%, carbon content control be controlled between the 8.0%-9.9wt% at≤0.035wt%, Ni content; The converter terminal temperature is controlled between 1600 ℃ ~ 1670 ℃;
3) stove external oxidation dephosphorization: utilize the oxidizing atmosphere dephosphorization after the tapping, the molten steel phosphorus content is controlled at≤0.0040wt%, add the oxidisability slag charge;
4) ladle deslagging: behind the dephosphorization, according to temperature regime, ladle is entered the LF stove carry out hyperthermic treatment, then slag in the ladle is got rid of, prevent rephosphorization after the desulfurization; At first molten steel is heated up at the LF stove, during temperature to 1630 ℃ ~ 1650 ℃, ladle handling to deslagging position is mentioned, the below prepares to be subjected to the steel ladle, pulls open lower mouth of a river push-pull valve, molten steel is injected be subjected to the steel ladle, treat to close push-pull valve before molten steel goes out only, the top slag is stayed in the ladle.
5) LF refining: deoxidation, desulfurization are controlled at sulphur content≤0.0020wt%;
6) RH refining: H content is controlled at≤0.0003wt%; Then cast.
2. method according to claim 1 is characterized in that, the main component mass percent of the oxidisability slag charge described in the step 3) is: CaO:50% ~ 70%, FeO:15% ~ 35%, Fe 2O 3: 5% ~ 15%, CaF 2: 2% ~ 10%.
3. method according to claim 1 is characterized in that, being subjected to described in the step 4) prepared the wash heat slag charge in the steel ladle and contained the Al reductor, and CaO content 〉=85wt% in the wash heat slag charge, all the other content are CaF 2And other inevitable impurity element.
CN201210575869XA 2012-12-26 2012-12-26 Smelting method of 9Ni steel Pending CN102978332A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103602888A (en) * 2013-12-02 2014-02-26 南京钢铁股份有限公司 Low-compression ratio hot-rolled 9Ni steel thick plate and manufacturing method thereof
CN105018669A (en) * 2015-07-15 2015-11-04 邢台钢铁有限责任公司 Method for producing technically pure iron for nuclear power
CN106811569A (en) * 2015-12-02 2017-06-09 鞍钢股份有限公司 A kind of method of producing ultra-low phosphorous steel by converter
CN107604120A (en) * 2017-09-12 2018-01-19 攀钢集团攀枝花钢铁研究院有限公司 Low-phosphorous low-sulfur method for making steel
CN108715913A (en) * 2018-06-07 2018-10-30 舞阳钢铁有限责任公司 A kind of method of electric furnace smelting 9Ni steel

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1372009A (en) * 2001-02-22 2002-10-02 武钢实业星源总公司 Dephosphorizing agent for molten iron and steel
JP3922181B2 (en) * 2002-12-27 2007-05-30 Jfeスチール株式会社 Melting method of high clean steel
CN101054647A (en) * 2007-05-26 2007-10-17 山西太钢不锈钢股份有限公司 Method of producing low-temperature high-toughness steel and steel plate
CN101104876A (en) * 2006-12-07 2008-01-16 首钢总公司 Method for producing ultra-low phosphoretic steel by molten steel dephosphorising outside furnace
CN101328529A (en) * 2008-06-30 2008-12-24 鞍钢股份有限公司 Technological process for molten steel secondary refining dephosphorization to produce ultra-low phosphorus steel
CN101831523A (en) * 2009-03-09 2010-09-15 鞍钢股份有限公司 Molten steel ladle external dephosphorizing device and dephosphorizing method thereof
CN102747181A (en) * 2011-04-18 2012-10-24 宝山钢铁股份有限公司 Smelting method of 9Ni steel

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1372009A (en) * 2001-02-22 2002-10-02 武钢实业星源总公司 Dephosphorizing agent for molten iron and steel
JP3922181B2 (en) * 2002-12-27 2007-05-30 Jfeスチール株式会社 Melting method of high clean steel
CN101104876A (en) * 2006-12-07 2008-01-16 首钢总公司 Method for producing ultra-low phosphoretic steel by molten steel dephosphorising outside furnace
CN101054647A (en) * 2007-05-26 2007-10-17 山西太钢不锈钢股份有限公司 Method of producing low-temperature high-toughness steel and steel plate
CN101328529A (en) * 2008-06-30 2008-12-24 鞍钢股份有限公司 Technological process for molten steel secondary refining dephosphorization to produce ultra-low phosphorus steel
CN101831523A (en) * 2009-03-09 2010-09-15 鞍钢股份有限公司 Molten steel ladle external dephosphorizing device and dephosphorizing method thereof
CN102747181A (en) * 2011-04-18 2012-10-24 宝山钢铁股份有限公司 Smelting method of 9Ni steel

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103602888A (en) * 2013-12-02 2014-02-26 南京钢铁股份有限公司 Low-compression ratio hot-rolled 9Ni steel thick plate and manufacturing method thereof
CN103602888B (en) * 2013-12-02 2015-05-27 南京钢铁股份有限公司 Manufacturing method for low-compression ratio hot-rolled 9Ni steel thick plate
CN105018669A (en) * 2015-07-15 2015-11-04 邢台钢铁有限责任公司 Method for producing technically pure iron for nuclear power
CN105018669B (en) * 2015-07-15 2017-03-08 邢台钢铁有限责任公司 A kind of production method of nuclear power ingot iron
CN106811569A (en) * 2015-12-02 2017-06-09 鞍钢股份有限公司 A kind of method of producing ultra-low phosphorous steel by converter
CN107604120A (en) * 2017-09-12 2018-01-19 攀钢集团攀枝花钢铁研究院有限公司 Low-phosphorous low-sulfur method for making steel
CN108715913A (en) * 2018-06-07 2018-10-30 舞阳钢铁有限责任公司 A kind of method of electric furnace smelting 9Ni steel

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Application publication date: 20130320