JP2969579B2 - Steel continuous casting method - Google Patents

Steel continuous casting method

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Publication number
JP2969579B2
JP2969579B2 JP30121391A JP30121391A JP2969579B2 JP 2969579 B2 JP2969579 B2 JP 2969579B2 JP 30121391 A JP30121391 A JP 30121391A JP 30121391 A JP30121391 A JP 30121391A JP 2969579 B2 JP2969579 B2 JP 2969579B2
Authority
JP
Japan
Prior art keywords
casting
molten steel
steel
density
continuous casting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
JP30121391A
Other languages
Japanese (ja)
Other versions
JPH05111736A (en
Inventor
孝宣 石井
昌文 瀬々
栄一 竹内
庄三 溝口
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Priority to JP30121391A priority Critical patent/JP2969579B2/en
Publication of JPH05111736A publication Critical patent/JPH05111736A/en
Application granted granted Critical
Publication of JP2969579B2 publication Critical patent/JP2969579B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【産業上の利用分野】本発明は、溶鋼成分が互いに異な
る複数の鋼種を連続的に鋳造する際に、成分が異なる鋼
種の間の鋳片内成分混合領域を最小限に抑える方法に関
するものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for minimizing a mixed area of components in a slab between steel types having different components when continuously casting a plurality of steel types having different molten steel components. is there.

【0002】[0002]

【従来の技術】鋼の連続鋳造にあたり、生産性を向上さ
せ、かつ製造コストの低減を図るために、複数の溶鋼鍋
の溶鋼を1つの鋳型内で連続的に鋳造する方法いわゆる
連々鋳が広く行われている。
2. Description of the Related Art In continuous casting of steel, a method of continuously casting molten steel in a plurality of molten steel pots in one mold in order to improve productivity and reduce manufacturing cost, so-called continuous casting, is widely used. Is being done.

【0003】また、これをさらに拡張した方法として、
溶鋼成分が互いに異なる複数の鋼種の連々鋳いわゆる異
鋼種連々鋳が実施されている。
[0003] As a further expanded method,
2. Description of the Related Art Continuous casting of a plurality of steel types having different molten steel components, so-called continuous casting of different steel types, is performed.

【0004】しかし、異鋼種連々鋳を実施する際には、
溶鋼鍋を交換する時に鋳造した部分(継目部)で成分混
合が生じ、その結果、成分が製造目的に合わない鋳片が
できるため、継目部の鋳片を格落ち処理やスクラップ処
理あるいは、継目部前後の鋳片を成分判定結果が出るま
での間圧延を保留するため、これらの障害が異鋼種連々
鋳の大きな問題となっていた。
[0004] However, when continuously casting different types of steel,
When exchanging the molten steel ladle, components are mixed in the cast part (seam part), and as a result, slabs whose components do not meet the purpose of production are produced, so the slab of the seam part is degraded, scrapped, or seamed. Since the rolling of the slabs before and after the part is suspended until the result of the component determination is obtained, these obstacles have been a major problem in successive casting of different steel types.

【0005】そこで、この異鋼種連々鋳を行なう際に発
生する継目部の成分混合を低減する方法として、タンデ
ィッシュ内の前鍋の残湯量をできる限り少なくしたのち
に後鍋の溶鋼を注入することによってタンディッシュで
の成分混合を防止する方法、後鍋の溶鋼の鋳造を開始す
るときの鋳造速度を一時的に低下させ、注湯ノズルから
の吐出流が鋳型内溶鋼中に浸透する深さを浅くして鋳型
内での混合を防止する方法、継目部で一旦鋳造を中止
し、鋳型内に鉄板を遮蔽板として挿入して鋳型内での混
合を防止する方法、静磁場を鋳型直下に形成し、継目部
で循環流を抑制しながら鋳造する方法(特開昭61―1
459号公報参照)等が提案されている。
[0005] In order to reduce the mixing of the components at the joints generated during the continuous casting of different types of steel, the molten steel in the rear pan is poured after the remaining hot water in the front pan in the tundish is reduced as much as possible. Method to prevent the mixing of components in the tundish by temporarily reducing the casting speed when starting the casting of molten steel in the back pan, and the depth at which the discharge flow from the pouring nozzle penetrates into the molten steel in the mold Method to prevent mixing in the mold by making it shallow, to temporarily stop casting at the joint, and to prevent mixing in the mold by inserting an iron plate as a shielding plate in the mold, and to apply a static magnetic field directly under the mold Forming and casting while suppressing the circulating flow at the seam
No. 459) has been proposed.

【0006】[0006]

【発明が解決しようとする課題】しかしながら、前記の
ような従来の技術では、継目部毎に鋳造速度を低下させ
るため、連続鋳造自体の生産性を損ねるばかりか、これ
により鋳片の温度が部分的に低くなるため、鋳片の曲げ
・矯正等での連鋳機への機械的負荷が大きくなって設備
寿命が短くなること、熱間直送圧延のスケジュールに障
害を与えること、鉄板を鋳型内に挿入するために極めて
危険な作業を伴うこと、更に、これら改善のわりには異
鋼種連々鋳時の継目部における成分混合領域を必ずしも
満足のいく程度にまで減少させているとはいえず、得ら
れた鋳片中の格落ち部分の長さあるいは屑化部分の長さ
の判定が困難である。
However, in the prior art as described above, since the casting speed is reduced at each joint, not only the productivity of continuous casting itself is impaired, but also the temperature of the cast slab is partially reduced. Mechanical load on the caster in bending and straightening of the cast slab, etc., which shortens the equipment life, impedes the schedule of hot direct rolling, and places the iron plate in the mold. In addition, it is not possible to say that the mixed area of the joints at the time of continuous casting of different types of steels is not necessarily reduced to a satisfactory degree, and that it is not necessarily satisfactory. It is difficult to determine the length of the degraded portion or the length of the scraped portion in the cast slab.

【0007】そのため、これを補う方法として、継目部
前後の鋳片に対して成分チェックを実施している。
Therefore, as a method of compensating for this, a component check is performed on the cast pieces before and after the joint.

【0008】従って、圧延のスケジュールを乱すのみな
らず、一時的に在庫(余材)量の拡大を招く問題があっ
た。
Therefore, there is a problem that not only the rolling schedule is disturbed, but also the inventory (surplus material) temporarily increases.

【0009】このことは、前述したように、磁場の存在
下で循環流を抑制しながら鋳造するだけでは不十分であ
り、全く流れのない状態(プラグフロー)にする必要が
あることを意味し、本発明はこの点を解決することを目
的としている。
[0009] This means that, as described above, it is not sufficient to only perform casting while suppressing the circulating flow in the presence of a magnetic field, and it is necessary to make a state in which there is no flow (plug flow). The present invention aims to solve this problem.

【0010】[0010]

【課題を解決するための手段】本発明者らは、上記問題
点を解決するため、種々の研究を積み重ねた結果、以下
の手段を見い出した。
Means for Solving the Problems The present inventors have conducted various studies to solve the above problems, and as a result, have found the following means.

【0011】すなわち、溶鋼成分が互いに異なる鋼を連
続的に鋳造するにあたり、溶鋼密度の大きい鋼種から小
さい鋼種へと順に鋳造する。
That is, when continuously casting steels having different molten steel components, the steels are cast in order from a steel type having a high molten steel density to a steel type having a low molten steel density.

【0012】特に、鋳型内の対向する広面またはその後
方に一対の磁石を配設した鋳型を用い、鋳片の厚みを横
切る方向に直流磁束を広面全幅に亙って付与して、鋳型
内鋳造方向に該直流磁束による静磁場帯を形成し、その
上側鋳造空間に溶鋼を注入して溶鋼密度の大きい鋼種か
ら順に鋳造する鋼の連続鋳造方法である。
In particular, using a mold having a pair of magnets disposed on the opposite wide surface in the mold or behind the same, a direct current magnetic flux is applied across the wide surface in the direction crossing the thickness of the slab, and the casting in the mold is performed. This is a continuous casting method for steel in which a static magnetic field zone is formed in the direction by the DC magnetic flux, molten steel is poured into a casting space above the casting, and steel is cast in ascending order of molten steel density.

【0013】[0013]

【作用】以下に、本発明を作用とともに詳細に説明す
る。
The following is a detailed description of the present invention along with the operation.

【0014】本発明者らは、従来の技術における前記問
題を解決すべく、異鋼種連々鋳の際に、2種の溶鋼の密
度差と鋳片に付与した静磁場とが成分混合に及ぼす影響
について詳細に研究した。
In order to solve the above-mentioned problems in the prior art, the present inventors have studied the effect of the difference in density between two types of molten steel and the static magnetic field imparted to the slab on the mixing of components during successive casting of different steel types. Was studied in detail.

【0015】図1に、連々鋳時の前鍋溶鋼と後鍋溶鋼と
の密度差と成分混合領域の鋳造方向長さ、すなわち溶鋼
浸入深さとの関係を示す。
FIG. 1 shows the relationship between the difference in density between the molten steel in the front ladle and the molten steel in the rear lane and the length in the casting direction of the component mixing region, ie, the depth of molten steel penetration, during continuous casting.

【0016】この図より前鍋溶鋼の密度が後鍋溶鋼の密
度よりも大きな場合、すなわち、2種溶鋼の密度差Δρ
が負の場合には、成分混合領域の長さが短くなることが
わかる。
From this figure, when the density of the molten steel in the front ladle is higher than the density of the molten steel in the rear ladle, ie, the density difference Δρ between the two types of molten steel
Is negative, it can be seen that the length of the component mixing region becomes shorter.

【0017】これはストランドプール内での密度差に基
づく溶鋼の混合が抑えられたためと考えられる。このよ
うに、連々鋳を実施する場合には、溶鋼の物性値すなわ
ち密度を考慮することが重要である。
This is probably because the mixing of molten steel based on the density difference in the strand pool was suppressed. Thus, when performing continuous casting, it is important to consider the physical property value, that is, the density, of the molten steel.

【0018】次に、鋳片へ静磁場を付与した場合の成分
混合領域長さの低減効果を図2に規格化濃度について示
す。静磁場の付与により、成分混合領域が大幅に低減す
ることがわかる。また、前鍋溶鋼への影響は、ほぼ継目
となるメニスカス位置から静磁場帯の中心位置までの長
さに低減される。
Next, the effect of reducing the length of the component mixed region when a static magnetic field is applied to the slab is shown in FIG. 2 for the normalized concentration. It can be seen that the application of the static magnetic field significantly reduces the component mixing region. In addition, the influence on the molten steel in the front ladle is reduced to a length from the meniscus position, which is almost a joint, to the center position of the static magnetic field zone.

【0019】これは、静磁場により吐出流にブレーキ効
果(ローレンツ力)が働いて鋳片横断面内の速度分布が
均一化(整流化)され、ストランドプール内への吐出流
の浸入深さが浅くなったためである。特に、この溶鋼の
混合抑制効果は前鍋溶鋼の密度が後鍋溶鋼の密度より大
きな場合に著しい。
This is because a brake effect (Lorentz force) acts on the discharge flow due to the static magnetic field, so that the velocity distribution in the cross section of the slab is made uniform (rectified), and the penetration depth of the discharge flow into the strand pool is reduced. Because it became shallow. In particular, the effect of suppressing the mixing of molten steel is remarkable when the density of the molten steel in the front ladle is higher than the density of the molten steel in the rear ladle.

【0020】これは、前鍋溶鋼の密度が後鍋溶鋼の密度
より小さな場合には、吐出流が一旦静磁場で整流化され
ても、継目部が静磁場帯を通過した後に密度差に基づく
対流混合が生じるのに対して、前鍋溶鋼の密度が後鍋溶
鋼の密度より大きな場合には、それが起こらず整流化さ
れた状態が維持されるためである。
This is because when the density of the molten steel in the front ladle is smaller than the density of the molten steel in the rear ladle, even if the discharge flow is once rectified by the static magnetic field, it is based on the density difference after the seam passes through the static magnetic field zone. If the density of the molten steel in the front ladle is higher than the density of the molten steel in the rear lane while the convection mixing occurs, this does not occur and the rectified state is maintained.

【0021】以上のように、異鋼種連々鋳にあたり鋼種
間の溶鋼の密度差を考慮することで、また、さらに静磁
場の付与と組合せることで継目部の成分混合領域を低減
できることがわかった。
As described above, it has been found that the component mixing region of the joint portion can be reduced by taking into account the difference in the density of the molten steel between the steel types in the continuous casting of different steel types, and by further combining this with the application of a static magnetic field. .

【0022】[0022]

【実施例】図3に示すような鋳型内の対向する広面の後
方に一対の電磁石を配設した鋳型を有する連続鋳造装置
を用い、異鋼種連々鋳を実施した。
EXAMPLE Continuous casting of different types of steel was performed using a continuous casting apparatus having a mold in which a pair of electromagnets were disposed behind opposing wide surfaces in a mold as shown in FIG.

【0023】鋳型形状は245mm(厚)×1500m
m(幅)で、鋳造速度は1.0m/minとした。静磁
場帯の位置は鋳型内メニスカスより450mm〜700
mmの範囲とし、直流磁束の強度は0.35テスラとし
た。溶鋼は、この静磁場の上側鋳造空間に注入した。
The shape of the mold is 245 mm (thickness) x 1500 m
m (width) and the casting speed was 1.0 m / min. The position of the static magnetic field zone is 450 mm to 700 from the meniscus in the mold.
mm, and the intensity of the DC magnetic flux was 0.35 Tesla. Molten steel was injected into the upper casting space of the static magnetic field.

【0024】鋳造後得られたスラブ内の溶質濃度分布を
調査し、成分混合領域の長さすなわち溶鋼浸入深さを求
めた。第1表に連々鋳を行ったときの鋳造条件と成分混
合領域の長さの関係を示す。本発明例では、比較例に比
べていずれも成分混合領域の大幅な低減効果が得られる
ことがわかる。
The solute concentration distribution in the slab obtained after casting was investigated, and the length of the component mixed region, that is, the molten steel penetration depth was determined. Table 1 shows the relationship between the casting conditions and the length of the component mixture region when continuous casting was performed. It can be seen that in each of the examples of the present invention, a remarkable effect of reducing the component mixed region can be obtained as compared with the comparative example.

【0025】[0025]

【表1】 [Table 1]

【0026】[0026]

【発明の効果】以上述べたように、本発明によれば、異
鋼種連々鋳の際の継目部の成分混合領域を、生産性を損
なわずに低減することができ、製造コストの低減など工
業的にもたらされる効果は大きい。
As described above, according to the present invention, it is possible to reduce the component mixing region of the joint at the time of continuous casting of different steel types without impairing productivity, and to reduce the manufacturing cost. The effect brought about is great.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明の効果を示す図で、密度差と成分混合領
域の長さの関係を示す。
FIG. 1 is a graph showing the effect of the present invention, showing the relationship between the density difference and the length of a component mixed region.

【図2】本発明の効果を示す図で、静磁場を付与したと
きに成分混合領域の長さに及ぼす影響を示す。
FIG. 2 is a diagram showing the effect of the present invention, showing the effect on the length of a component mixing region when a static magnetic field is applied.

【図3】本発明を実施するにあたって、使用した連続鋳
造装置鋳型部分の概略図、(a)はその見取図、(b) は鋳
片幅方向の断面図である。
FIG. 3 is a schematic view of a continuous casting apparatus mold portion used in carrying out the present invention, (a) is a sketch drawing thereof, and (b) is a cross-sectional view in a slab width direction.

【符号の説明】[Explanation of symbols]

1 浸漬ノズル 2 静磁場帯 3 鋳型長辺 4 鋳型 5 整流化 DESCRIPTION OF SYMBOLS 1 Immersion nozzle 2 Static magnetic field zone 3 Mold long side 4 Mold 5 Rectification

───────────────────────────────────────────────────── フロントページの続き (72)発明者 溝口 庄三 富津市新富20―1 新日本製鐵株式会社 技術開発本部内 (56)参考文献 特開 昭58−168464(JP,A) 特開 昭61−1459(JP,A) (58)調査した分野(Int.Cl.6,DB名) B22D 11/00 B22D 11/10 ──────────────────────────────────────────────────続 き Continued on the front page (72) Shozo Mizoguchi, Inventor 20-1 Shintomi, Futtsu City Nippon Steel Corporation Technology Development Division (56) References JP-A-58-1868464 (JP, A) JP-A Sho 61-1459 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) B22D 11/00 B22D 11/10

Claims (2)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】 溶鋼成分が互いに異なる鋼を連続的に鋳
造するにあたり、溶鋼密度の大きい鋼種から小さい鋼種
へと順に鋳造することを特徴とする鋼の連続鋳造方法。
1. A continuous casting method for steel, characterized in that, when continuously casting steels having different molten steel components, steels having a higher molten steel density are cast in order from a steel type having a smaller molten steel density.
【請求項2】 鋳型内の対向する広面またはその後方に
一対の磁石を配設した鋳型を用い、鋳片の厚みを横切る
方向に直流磁束を広面全幅に亙って付与して鋳型内鋳造
方向に該直流磁束による静磁場帯を形成し、その上側鋳
造空間に溶鋼を注入して溶鋼密度の大きい鋼種から順に
鋳造することを特徴とする請求項1記載の鋼の連続鋳造
方法。
2. A casting mold in which a pair of magnets are disposed on the opposite wide surface in the mold or at the rear thereof, and a direct current magnetic flux is applied across the entire width of the wide surface in a direction crossing the thickness of the slab. 2. The continuous casting method for steel according to claim 1, wherein a static magnetic field zone is formed by the DC magnetic flux, and molten steel is poured into a casting space above the casting and casting is performed in order from a steel type having a higher molten steel density.
JP30121391A 1991-10-22 1991-10-22 Steel continuous casting method Expired - Lifetime JP2969579B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP30121391A JP2969579B2 (en) 1991-10-22 1991-10-22 Steel continuous casting method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP30121391A JP2969579B2 (en) 1991-10-22 1991-10-22 Steel continuous casting method

Publications (2)

Publication Number Publication Date
JPH05111736A JPH05111736A (en) 1993-05-07
JP2969579B2 true JP2969579B2 (en) 1999-11-02

Family

ID=17894151

Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Status (1)

Country Link
JP (1) JP2969579B2 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7047647B2 (en) * 2018-07-23 2022-04-05 日本製鉄株式会社 Continuous casting method for thin slabs

Also Published As

Publication number Publication date
JPH05111736A (en) 1993-05-07

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