CN101992280A - Method for reducing inclusion content of casting blank - Google Patents

Method for reducing inclusion content of casting blank Download PDF

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Publication number
CN101992280A
CN101992280A CN2009100131242A CN200910013124A CN101992280A CN 101992280 A CN101992280 A CN 101992280A CN 2009100131242 A CN2009100131242 A CN 2009100131242A CN 200910013124 A CN200910013124 A CN 200910013124A CN 101992280 A CN101992280 A CN 101992280A
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CN
China
Prior art keywords
tundish
molten steel
inert gas
casting
steel
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Pending
Application number
CN2009100131242A
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Chinese (zh)
Inventor
雷洪波
许刚
张晓军
曹维华
李惊鸿
叶印鹏
薛军
徐向阳
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Angang Steel Co Ltd
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Angang Steel Co Ltd
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Filing date
Publication date
Application filed by Angang Steel Co Ltd filed Critical Angang Steel Co Ltd
Priority to CN2009100131242A priority Critical patent/CN101992280A/en
Publication of CN101992280A publication Critical patent/CN101992280A/en
Pending legal-status Critical Current

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Abstract

The invention discloses a method for reducing inclusion content of a casting blank. The production processes comprise steel making, refining, continuous casting, heating in a heating furnace and continuous rolling. The method is characterized in that: during continuous casting, before molten steel is injected into a tundish, an inert gas is blown into the tundish by using a breather pipe above the tundish; after the interior of the tundish is basically covered by the inert gas, a long nozzle at the bottom of a molten steel tank is opened so that the molten steel enters the tundish; after the molten steel in the tundish reaches 1/4 of the height of the tundish, a covering agent is added into the tundish; and after the covering agent is melted and the molten steel is fully covered, the blowing of the inert gas is stopped. The tundish is covered by the inert gas blown into the tundish before casting, and then the molten steel at the initial casting stage is prevented from directly contacting the atmosphere so that air suction and secondary oxidation of the molten steel are avoided and the purpose of reducing the inclusion in the casting blank is fulfilled.

Description

A kind of method that reduces inclusion content in the strand
Technical field
The present invention relates to a kind of method that improves slab quality, particularly relate to a kind of method that in casting process, reduces inclusion content in the strand.
Background technology
Traditional continuous casting manufacturing technique is: steelmaking-refining-continuous casting.Usually make steel with conventional electric furnace or converter, continuous casting is carried out at square billet or slab caster, after strand is sheared through bending straightening after in LF and RH or VD purifier molten steel being carried out refining in steel-making back, be sent to next process, carry out subsequent handling and handle.
In the above-mentioned technology, the control method that inclusion content adopted is mainly contained: in converter steelmaking process, under the liquid steel temperature and member condition that guarantee the steel grade regulation, control the oxidisability of molten steel as far as possible, during tapping molten steel is carried out normal deoxidation alloying, adopt the pushing off the slag technology when tapping finishes, avoid the oxidisability slag to enter in the molten steel jar, cause the secondary oxidation of molten steel; When RH or VD handle, generally carry out omnidistance Argon, molten steel is carried out weak Argon handling the later stage, remove the residual gas in the steel as far as possible and be mingled with; In casting process, mainly adopt molten steel control stream technology in the tundish, long nozzle argon encapsulation technique, two cold-zone electromagnetic agitating technologies etc.During the routine continuous casting, be that long nozzle by the molten steel pot bottom makes molten steel inject tundish, after the molten steel in the tundish reaches certain height, in tundish, add packed diffusing shape coverture, after a period of time on the surface of coverture molten steel in tundish the fusing and molten steel is covered fully, at this moment the molten steel in the tundish is just isolated fully with atmosphere, again secondary oxidation can not take place; Molten steel enters crystallizer by the submersed nozzle of pans below therebetween, and molten steel forms strand through behind the crystallizer.
In the said method,, the molten steel that enters tundish is not taked any safeguard measure at the cast initial stage; at this moment, the molten steel in the tundish directly contacts with atmosphere, thereby secondary oxidation can take place molten steel; make that oxide inclusions increases in the steel, and cause casting blank defect and waste product thus.
Summary of the invention
In order to overcome above-mentioned defective, problem to be solved by this invention is the cast initial stage, and molten steel contacts, takes place secondary oxidation, makes the problem that oxide inclusions increases in the steel with atmosphere, thus the casting blank defect that reduces field trash total amount in the strand and bring thus, the final waste product that reduces improves the quality of products.
Concrete technical scheme of the present invention is as follows:
Steel-making: adopt conventional converter, control the composition and the temperature of molten steel routinely, the pushing off the slag tapping.
Refining: adopt in the refining of conventional LF stove, VD or the RH purifier molten steel is carried out refining and degassing processing;
Continuous casting: before molten steel injects tundish, above tundish, in tundish, be blown into inert gas with breather pipe, after a few minutes, after promptly treating to be covered by inert gas substantially in the tundish, the long nozzle of opening the molten steel pot bottom again makes molten steel enter tundish approximately, after the molten steel in the tundish reaches 1/4 place of tundish height, in tundish, add coverture again, after the coverture fusing and molten steel being covered fully, stop blown inert gas.Like this when cast initial stage molten steel injects tundish, though do not obtain the covering of coverture this moment in the tundish on the molten steel face, owing in the tundish substantially by the capping of inert gas institute, so molten steel can not contact with atmosphere, so secondary oxidation can not take place, avoid the increase of steel inclusion.
By being blown into inert gas opening to water in the forward direction tundish, can make the molten steel of opening the initial stage of watering avoid directly contacting, thereby avoid molten steel that air-breathing, secondary oxidation takes place with atmosphere, reduce field trash total amount in the strand, reduce casting blank defect and waste product, improve the quality of products.
The specific embodiment
Below the specific embodiment of the present invention is described further:
1, steel-making: adopts 100 tons of converters, charge weight: 94.6 tons of molten iron, 12.4 tons of steel scraps, after molten steel composition and temperature reached requirement, pushing off the slag was tapped.
2, refining: adopt the refining of LF stove, VD purifier that molten steel is carried out refining and degassing processing, make the temperature of molten steel and the regulation requirement that composition all reaches the machine continuous casting, molten steel is carried out omnidistance Argon therebetween;
3, continuous casting: before tundish injected molten steel, on tundish top, (φ 32mm) was blown into nitrogen in tundish with breather pipe at the long nozzle that passes through the molten steel pot bottom, and nitrogen pressure is 0.4MPa; Treat in the tundish substantially by (about 2~3min), the mouth of a river of opening the molten steel pot bottom again makes molten steel enter tundish after the nitrogen capping; After the molten steel in the tundish reaches certain height (300mm), in tundish, add coverture again; In the coverture fusing and after molten steel is covered fully (about 2min), stop for nitrogen.Casting back billet bloom size is 280mm * 380mm * 7100mm, and gross weight is 95.327 tons.
4, tandem rolling: above-mentioned strand is admitted to soaking pit, carries out hot continuous rolling after the heating, and the square steel handling is rolled off the production line and carried out stacking slow cooling after rolling, and square steel is of a size of 154mm * 154mm * 9000mm, and gross weight is 94.238 tons, and de-stacking after 30 hours transports the check of steel billet storehouse to.
Assay: the total oxygen average content of first strand of first jar of steel significantly reduces, and originally is 15ppm, is 10ppm (seeing Table 1) now; The nitrogen average content slightly increases, and originally is 49ppm, is 51ppm (seeing Table 2) now; The field trash average content significantly reduces, and originally is 80ppm, is 52ppm (seeing Table 3) now; Tandem rolling square steel flaw detection qualification rate significantly improves, and originally is 84.89%, now for being 99.03%, has improved about 14% (seeing Table 4) than in the past.
Table 1 strand total oxygen content/%
Table 2 strand nitrogen content/%
Table 3 casting blank foreign matter total amount/%
Table 4 tandem rolling square steel flaw detection situation
Embodiments of the present invention not only can be blown into nitrogen to tundish, can also be blown into argon gas.When being blown into nitrogen, be particularly suitable for nitrogenous steel grade; When being blown into argon gas, be applicable to all steel grades substantially, especially high purity steel; During nitrogen flushing, expense is lower, is 1/5 of Argon approximately.

Claims (4)

1. method that reduces inclusion content in the strand, comprise following production technology: steel-making → refining → continuous casting → heating furnace heating → tandem rolling, it is characterized in that: in casting process, before molten steel injects tundish, above tundish, in tundish, be blown into inert gas with breather pipe, after treating to be covered by inert gas substantially in the tundish, the long nozzle of opening the molten steel pot bottom again makes molten steel enter tundish, when the molten steel in the tundish reach the tundish height more than 1/4 after, in tundish, add coverture again, after the coverture fusing and molten steel being covered fully, stop blown inert gas.
2. the method for inclusion content in the minimizing strand according to claim 1 is characterized in that: described inert gas is a nitrogen.
3. the method for inclusion content in the minimizing strand according to claim 1 is characterized in that: described inert gas is an argon gas.
4. the method for inclusion content in the minimizing strand according to claim 1 is characterized in that: arbitrary position that described breather pipe, its position can be above tundish.
CN2009100131242A 2009-08-10 2009-08-10 Method for reducing inclusion content of casting blank Pending CN101992280A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN2009100131242A CN101992280A (en) 2009-08-10 2009-08-10 Method for reducing inclusion content of casting blank

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN2009100131242A CN101992280A (en) 2009-08-10 2009-08-10 Method for reducing inclusion content of casting blank

Publications (1)

Publication Number Publication Date
CN101992280A true CN101992280A (en) 2011-03-30

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105478699A (en) * 2014-09-19 2016-04-13 鞍钢股份有限公司 Continuous casting method capable of reducing inclusion rate of hot rolled steel coils
KR20160067100A (en) * 2013-08-26 2016-06-13 닛신 세이코 가부시키가이샤 Continuous casting method
CN105682827A (en) * 2013-09-27 2016-06-15 日新制钢株式会社 Continuous casting method
CN107052289A (en) * 2017-05-09 2017-08-18 唐山不锈钢有限责任公司 The Adding Way of the tundish covering flux poured is opened for continuous casting
CN107159857A (en) * 2017-04-10 2017-09-15 首钢总公司 It is a kind of to prevent from opening the method for pouring process molten steel secondary oxidation
CN107671251A (en) * 2017-10-24 2018-02-09 首钢京唐钢铁联合有限责任公司 A kind of tundish hypoxemia position control method and device

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102084729B1 (en) * 2013-08-26 2020-03-04 닛테츠 닛신 세이코 가부시키가이샤 Continuous casting method
KR20160067100A (en) * 2013-08-26 2016-06-13 닛신 세이코 가부시키가이샤 Continuous casting method
EP3040138A4 (en) * 2013-08-26 2017-04-19 Nisshin Steel Co., Ltd. Continuous casting method
US9889499B2 (en) 2013-08-26 2018-02-13 Nisshin Steel Co., Ltd. Continuous casting method
CN105682827A (en) * 2013-09-27 2016-06-15 日新制钢株式会社 Continuous casting method
CN105682827B (en) * 2013-09-27 2018-05-04 日新制钢株式会社 Continuous casing
CN105478699A (en) * 2014-09-19 2016-04-13 鞍钢股份有限公司 Continuous casting method capable of reducing inclusion rate of hot rolled steel coils
CN107159857B (en) * 2017-04-10 2019-10-08 首钢集团有限公司 A method of it prevents from opening and pours process molten steel secondary oxidation
CN107159857A (en) * 2017-04-10 2017-09-15 首钢总公司 It is a kind of to prevent from opening the method for pouring process molten steel secondary oxidation
CN107052289B (en) * 2017-05-09 2019-06-28 唐山不锈钢有限责任公司 The Adding Way of the tundish covering flux poured is opened for continuous casting
CN107052289A (en) * 2017-05-09 2017-08-18 唐山不锈钢有限责任公司 The Adding Way of the tundish covering flux poured is opened for continuous casting
CN107671251A (en) * 2017-10-24 2018-02-09 首钢京唐钢铁联合有限责任公司 A kind of tundish hypoxemia position control method and device
CN107671251B (en) * 2017-10-24 2020-05-15 首钢京唐钢铁联合有限责任公司 Tundish low oxygen level control method and device

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Application publication date: 20110330