JPH05212511A - Method and device for improving internal quality in continuously cast slab - Google Patents

Method and device for improving internal quality in continuously cast slab

Info

Publication number
JPH05212511A
JPH05212511A JP4047640A JP4764092A JPH05212511A JP H05212511 A JPH05212511 A JP H05212511A JP 4047640 A JP4047640 A JP 4047640A JP 4764092 A JP4764092 A JP 4764092A JP H05212511 A JPH05212511 A JP H05212511A
Authority
JP
Japan
Prior art keywords
magnetic field
molten steel
stirring
mold
flow
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.)
Granted
Application number
JP4047640A
Other languages
Japanese (ja)
Other versions
JP3180164B2 (en
Inventor
Koichi Isobe
浩一 磯部
Hirofumi Maede
弘文 前出
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 JP04764092A priority Critical patent/JP3180164B2/en
Publication of JPH05212511A publication Critical patent/JPH05212511A/en
Application granted granted Critical
Publication of JP3180164B2 publication Critical patent/JP3180164B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Abstract

PURPOSE:To restrain the formation of equiaxed crystal, prevent the deterioration of quality caused by inclusions and obtain a cast slab having excellent internal quality by acting magnetic field to molten steel in a mold, stirring, acting static magnetic field to the molten steel at downstream side from the magnetic field acting position and braking the descending flow according to the stirring. CONSTITUTION:In addition to an electromagnetic stirring device 3 in a mold and an electromagnetic stirring device 6 for secondary cooling zone, an electromagnet 4 is newly arranged just below the mold and Tesla static magnetic field is added in the thickness direction of a cast slab and the braking force is given to the descending flow developed with the stirring in the mold. The stirring is given at 40-50cm/sec molten steel flow speed in the mold and at 20-50cm/sec of the electromagnetic stirring in the secondary cooling zone. Therefore, to the descending flow of the molten steel generated from action of a rotating or shifting magnetic field generating device 3, by giving the static magnetic field in the direction crossing at the right angle just below the descending flow with the static magnetic field generating device 4, the braking force can be acted to the descending molten steel flow.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は連続鋳造法で製造される
炭素鋼鋳片の内質改善方法および装置に関するものであ
る。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for improving the internal quality of carbon steel slabs produced by continuous casting.

【0002】[0002]

【従来の技術】従来、連続鋳造法で凝固組織の等軸晶化
を促進させる方法としては、鋳型内、二次冷却帯、溶鋼
凝固末期部における電磁攪拌がある(特願昭58―25
1455)。
2. Description of the Related Art Conventionally, as a method for accelerating the equiaxed crystallization of a solidification structure in a continuous casting method, there is electromagnetic stirring in a mold, a secondary cooling zone, and a molten steel solidification final stage (Japanese Patent Application No. 58-25).
1455).

【0003】電磁攪拌の効果については鉄と鋼第67年
(1981)第8号P1287及びP1297に述べら
れている。
The effect of electromagnetic stirring is described in Iron and Steel 1987 (1981) No. 8 P1287 and P1297.

【0004】特に、凝固組織の等軸晶化や鋳型内でのデ
ッケルの生成防止に鋳型内の電磁攪拌が顕著な効果を有
することが一般に認識されてきている。
In particular, it has been generally recognized that electromagnetic stirring in the mold has a remarkable effect on the equiaxed crystallization of the solidification structure and the prevention of deckle formation in the mold.

【0005】しかし、これらの電磁攪拌を適用した場合
においても、等軸晶化が困難な鋼種においては鋳片等軸
晶率は大きくバラつき、目標とする等軸晶率が充分確保
されない場合が多い。
However, even when these electromagnetic stirrings are applied, the equiaxed crystal ratio of the slab greatly varies in steel types in which equiaxed crystal formation is difficult, and the target equiaxed crystal ratio is often not secured sufficiently. ..

【0006】また、回転型電磁攪拌装置、移動型電磁攪
拌装置いづれにおいても電磁気力で水平方向に駆動され
た溶鋼流動は鋳型内壁で向きを変え、ストランドの上下
流へ向う流動を引起こす。
In both the rotary type electromagnetic stirrer and the moving type electromagnetic stirrer, the molten steel flow horizontally driven by the electromagnetic force changes its direction at the inner wall of the mold, causing a flow upstream and downstream of the strand.

【0007】上流に向った流れによる湯面の盛り上がり
は操業者によく知られた現象であり、一方、下流へ向う
流動が生じているのは鋳片縦断面で観察される柱状晶組
織がメニスカス側へ傾斜して成長していることから認識
される事象である。
The swelling of the molten metal surface due to the flow toward the upstream is a phenomenon well known to operators, while the flow toward the downstream is caused by the columnar crystal structure observed in the longitudinal section of the slab of meniscus. It is an event that can be recognized from the fact that it grows to the side.

【0008】本発明者らが凝固組織の等軸晶化や介在物
品質と操業条件の関係について解析した際、鋳片縦断面
で観察される柱状晶組織の上流側への傾きが大きいほど
鋳片の等軸晶率が低下し、また、超音波探傷法で棒鋼成
品中心に検出される介在物欠陥が増大する傾向が認めら
れた。
When the present inventors analyzed the relationship between equiaxed crystallization of solidification structure and quality of inclusions and operating conditions, the larger the inclination of the columnar crystal structure observed in the longitudinal section of the slab toward the upstream side, the greater the castability. It was confirmed that the equiaxed crystal ratio of the piece decreased and the number of inclusion defects detected in the center of the steel bar product by ultrasonic flaw detection tended to increase.

【0009】特に、ほとんど同じ操業条件で鋳造された
鋳片において上記柱状晶の傾きが異なると鋳片の等軸晶
化や鋳片中心部の介在物レベルに大きな差が生じること
は注目に値する。
In particular, it is worth noting that if the columnar crystals have different inclinations in a slab cast under almost the same operating conditions, there will be a large difference in the equiaxed crystallization of the slab and the inclusion level at the center of the slab. ..

【0010】このような鋳片縦断面の柱状晶組織の上流
側への傾き増大は、凝固時に柱状デンドライト先端に存
在する下降流の流速が増大したことを示している。
Such an increase in the inclination of the columnar crystal structure of the longitudinal section of the cast slab to the upstream side indicates that the flow velocity of the downflow existing at the tip of the columnar dendrite during solidification increased.

【0011】よって、以上述べたことから、鋳型内電磁
攪拌により誘起される下降流は凝固組織の等軸晶化や鋳
片中心部の介在物品質に対して悪い影響を与え、下降流
が激しくなると等軸晶化が阻害され介在物レベルも低下
すると判断される。
Therefore, from the above, the downward flow induced by electromagnetic stirring in the mold has a bad influence on the equiaxed crystallization of the solidification structure and the quality of inclusions in the center of the slab, and the downward flow is severe. Then, it is judged that the equiaxed crystallization is hindered and the inclusion level is lowered.

【0012】[0012]

【発明が解決しようとする課題】本発明は連続鋳造法で
鋳型内電磁攪拌を適用して鋳片を製造するに際し、鋳型
内電磁攪拌により誘起される下降流による凝固組織の等
軸晶化抑制や介在物品質の劣化を防止して、充分な等軸
晶化を図り偏析、ポロシティーの少ない優れた内質の鋳
片製造方法を提供しよとするものである。
DISCLOSURE OF THE INVENTION The present invention suppresses equiaxed crystallization of a solidification structure by a downward flow induced by electromagnetic stirring in a mold when applying electromagnetic stirring in a mold by a continuous casting method to produce a slab. It is an object of the present invention to provide a method for producing an excellent quality ingot slab that prevents deterioration of the quality of inclusions and inclusions, achieves sufficient equiaxed crystallization, and has less segregation and porosity.

【0013】[0013]

【課題を解決するための手段】上記の課題を解決するた
めの手段として以下の2つの方法と装置がある。
There are the following two methods and devices as means for solving the above problems.

【0014】一つは、連続鋳造法により鋳片を製造する
に際し、鋳型内の溶鋼に電磁気力を作用して攪拌すると
共に、その攪拌位置より下流で電磁気力を作用させて溶
鋼流動を制動することを特徴とする連鋳鋳片の内質改善
方法と装置である。
First, when a slab is manufactured by the continuous casting method, an electromagnetic force acts on the molten steel in the mold to stir it, and an electromagnetic force is exerted downstream from the stirring position to dampen the molten steel flow. A method and apparatus for improving the internal quality of a continuous cast slab, which is characterized by the above.

【0015】もう一つは、連続鋳造法により鋳片を製造
するに際し、鋳型内の溶鋼に電磁気力を作用して攪拌す
ると共に、その攪拌位置より下流で電磁気力を作用させ
て溶鋼流動を制動し、さらにその下流位置で溶鋼に電磁
気力を作用して攪拌することを特徴とする連鋳鋳片の内
質改善方法と装置である。
The other is that when a cast slab is manufactured by the continuous casting method, the molten steel in the mold is stirred by applying an electromagnetic force, and the molten steel flow is damped by applying an electromagnetic force downstream from the stirring position. Further, the present invention provides a method and apparatus for improving the internal quality of a continuous cast slab, which comprises stirring the molten steel by applying an electromagnetic force to the molten steel at a position downstream thereof.

【0016】[0016]

【作用】本発明者らは鋳型内電磁攪拌により誘起される
下降流は凝固組織の等軸晶化を抑制し、介在物品質が劣
化することを見出すと共にこの下降流に起因する問題を
解決する方法について種々検討を加えた。
The present inventors have found that the downward flow induced by electromagnetic stirring in the mold suppresses equiaxed crystallization of the solidification structure and deteriorates the quality of inclusions, and solves the problem caused by this downward flow. Various studies were made on the method.

【0017】顕著な等軸晶化促進効果を有する鋳型内電
磁攪拌で攪拌により生じた下降流により凝固組織の等軸
晶化が阻害される原因は、攪拌でメニスカス近傍の比較
的高温の溶鋼流が凝固シェルに沿ってストランド内へ侵
入し、その際等軸晶の核生成に必要な凝固前面の過冷度
を消失させたり、等軸晶の核となるエンブリオを再溶解
するためと考えられる。
The reason why the equiaxed crystallization of the solidification structure is inhibited by the downward flow generated by stirring by electromagnetic stirring in the mold having a remarkable effect of promoting equiaxed crystallization is that the molten steel flow at a relatively high temperature near the meniscus is stirred. Is believed to invade into the strands along the solidification shell, at which time the supercooling degree of the solidification front necessary for nucleation of equiaxed crystals disappears and the embrio that becomes the nucleus of equiaxed crystals is redissolved. ..

【0018】一方、鋳型内電磁攪拌により生じた下降流
により鋳片中心部の介在物レベルが悪化するのは、ノズ
ル吐出孔から侵入した介在物や巻き込まれたパウダー等
がメニスカス部近傍で浮上分離されずに下降流に同伴さ
れてストランド内奥深くまで侵入するためと推察され
る。
On the other hand, the level of inclusions at the center of the slab deteriorates due to the downward flow generated by electromagnetic stirring in the mold, because the inclusions that have entered through the nozzle discharge holes and the entrained powder are separated by levitation in the vicinity of the meniscus. It is presumed that it is not accompanied by the descending flow and penetrates deeply into the strand.

【0019】この下降流に起因する等軸晶化の抑制や介
在物レベルの低下といった問題は、何等かの方法で鋳型
内電磁攪拌により生じる下降流を抑制することにより解
決可能と考え、その一つの方法として、鋳型内攪拌位置
より下流の位置において下降流を制動するように電磁気
力を作用させる方法を着想した。
It is considered that the problems such as suppression of equiaxed crystallization and reduction of inclusion level due to this downflow can be solved by suppressing the downflow caused by electromagnetic stirring in the mold by some method. As one method, the method of applying an electromagnetic force so as to brake the downward flow at a position downstream of the stirring position in the mold was conceived.

【0020】従来、鋳型に電磁石を設けて、ノズル噴流
を制動する試みもなされているが(杉沢ら:材料とプロ
セス、CAMP―ISIJ Vol.4(1981)―
1281)、メニスカス部の湯面変動防止や非金属介在
物の巻き込み防止する目的であり鋳型内電磁攪拌による
高温下降流の侵入を防止して、鋳片の等軸晶化促進を目
的としていない。
Conventionally, it has been attempted to provide an electromagnet on a mold to brake a nozzle jet (Sugizawa et al .: Materials and Processes, CAMP-ISIJ Vol. 4 (1981)-
1281), the purpose is to prevent fluctuations in the molten metal surface of the meniscus and to prevent entrainment of non-metallic inclusions, and to prevent the entry of a high temperature downward flow due to electromagnetic stirring in the mold, and not to promote equiaxed crystallization of cast slabs.

【0021】また、鋳型に溶鋼の下降流を制動する電磁
石を設置した場合、鋳片の等軸晶化に顕著な効果を有す
る鋳型内電磁攪拌の適用が困難で、その場合は偏析等の
内質改善に必要な等軸晶を安定して確保できないことが
予想される。
Further, when an electromagnet for damping the downward flow of molten steel is installed in the mold, it is difficult to apply electromagnetic stirring in the mold, which has a remarkable effect on equiaxed crystallization of the slab. It is expected that equiaxed crystals required for quality improvement cannot be stably secured.

【0022】図1に上記下降流抑制方法の実施態様を示
す。
FIG. 1 shows an embodiment of the downflow suppressing method.

【0023】回転または移動磁場発生装置3の作用によ
り発生した溶鋼の下降流に対しその直下で直交する方向
に静磁場を静磁場発生装置4により付加することにより
下降する溶鋼流に制動力を作用させることができる。
A static magnetic field is applied by the static magnetic field generator 4 to the downward flow of the molten steel generated by the action of the rotating or moving magnetic field generator 3 in a direction perpendicular to the downward flow of the molten steel, thereby exerting a braking force on the descending molten steel flow. Can be made

【0024】静磁場を付加する方向については鋳片の短
辺と平行な方向に付与する方向が磁場の減衰も少なく最
も有効と考えられる。
Regarding the direction in which the static magnetic field is applied, the direction in which the static magnetic field is applied in the direction parallel to the short side of the slab is considered to be the most effective because the magnetic field is less attenuated.

【0025】また、あまり、鋳型内電磁攪拌位置に近い
と下降流の有する運動量が大きくそれを制動するための
磁場強度をかなり大きくする必要が有り、また、制動力
を付加する位置が鋳型内の攪拌位置からあまり離れ過ぎ
ても凝固シェルが厚くなって、そのシェルでの減衰が大
きくなるため溶鋼流の制動に必要な磁場強度はかなりア
ップする。
Further, if it is too close to the electromagnetic stirring position in the mold, the momentum of the downward flow is large, and it is necessary to considerably increase the magnetic field strength for braking it, and the position where the braking force is applied is in the mold. Even if it is too far from the stirring position, the solidified shell becomes thick and the damping in the shell becomes large, so that the magnetic field strength necessary for damping the molten steel flow is considerably increased.

【0026】従って、制動力を付与する位置については
両者の兼合で最も適正な位置を選定すべきである。
Therefore, as for the position to apply the braking force, the most appropriate position should be selected in combination with both.

【0027】さらに、制動力をストランド方向に数段で
作用させることにより、より確実な下降流の抑制が実現
できる。
Further, by applying the braking force in several steps in the strand direction, more reliable suppression of the downward flow can be realized.

【0028】また、下降流と逆の方向へ、即ち上流へ向
って溶鋼を駆動させるように移動磁場を付与して下降流
を減衰しても上記静磁場を付与した場合と同様な効果が
期待できる。
Further, even if a moving magnetic field is applied so as to drive molten steel in the direction opposite to the downward flow, that is, toward the upstream side and the downward flow is attenuated, the same effect as when the static magnetic field is applied is expected. it can.

【0029】また、移動磁界による方法と静磁場を付加
して下降流を抑制する方法を組合せても良い。
Further, the method of using a moving magnetic field and the method of suppressing a downward flow by adding a static magnetic field may be combined.

【0030】上記で述べた静磁場または移動磁場を付与
して鋳型内電磁攪拌により誘起された下降流が抑制され
ると、高温流によりストランド内部の溶鋼の過冷度は消
失されず保持され、等軸晶の核となるエンブリオも再溶
解されないので凝固組織の等軸晶化は一層進み、下降流
が抑制されることでストランド内部へ侵入する介在物の
大幅な減少も期待できる。
When the above-mentioned static magnetic field or moving magnetic field is applied to suppress the downward flow induced by electromagnetic stirring in the mold, the supercooling degree of the molten steel in the strand is not lost by the high temperature flow, and is maintained. Since the embryo, which is the nucleus of the equiaxed crystal, is not redissolved, the equiaxed crystallization of the solidified structure further progresses, and the downward flow is suppressed, so that it is expected that the inclusions penetrating into the inside of the strand can be greatly reduced.

【0031】さらに、このようにメニスカスからの下降
流がほとんど存在せず、従って、メニスカスからの高温
流の影響を受けない条件で再度2次冷却帯で溶鋼を鋳造
軸まわりに攪拌すると、凝固前面の溶鋼過冷度を減少さ
せていた溶質濃化層が母溶鋼により希釈され、凝固前面
の溶鋼過冷度は増大し、且つ、その過冷領域が拡大する
結果、凝固組織の等軸晶化が一層促進される。
Further, when the molten steel is stirred around the casting shaft in the secondary cooling zone again under the condition that there is almost no downward flow from the meniscus and is not affected by the high temperature flow from the meniscus, the solidification front The solute-enriched layer, which had decreased the degree of supercooling of molten steel, was diluted by the mother molten steel, the degree of supercooling of molten steel on the solidification front increased, and the area of supercooling expanded, resulting in equiaxed crystallization of the solidification structure. Is further promoted.

【0032】[0032]

【実施例】更に本発明について実施例に基づき説明す
る。
EXAMPLES The present invention will be further described based on examples.

【0033】本発明の効果について確認するため鋳片断
面サイズが162mm×162mmの湾曲型連鋳機を用
いて難等軸晶化鋼種であるS48Cを鋳造した。
In order to confirm the effect of the present invention, S48C which is a refractory equiaxed steel grade was cast using a curved continuous casting machine having a slab cross section size of 162 mm × 162 mm.

【0034】本実施例におけるタンディッシュ溶鋼過熱
度は25〜45℃であり、鋳造速度は2.0〜2.5m
/分の範囲であった。
In the present embodiment, the tundish molten steel has a superheat of 25 to 45 ° C. and a casting speed of 2.0 to 2.5 m.
The range was / min.

【0035】図1に本発明の実施態様を示す。既存の鋳
型内電磁攪拌装置3と2次冷却帯の電磁攪拌装置6に加
え、新たに鋳型直下に電磁石4を設け鋳片厚み方向に1
テスラの静磁場を付加して鋳型内攪拌で生じる下降流に
対し制動力を付与した。
FIG. 1 shows an embodiment of the present invention. In addition to the existing electromagnetic stirrer 3 in the mold and the electromagnetic stirrer 6 in the secondary cooling zone, an electromagnet 4 is newly provided immediately below the mold 1 in the thickness direction of the cast piece.
A static magnetic field of Tesla was applied to apply a braking force to the downward flow generated by stirring in the mold.

【0036】鋳型内攪拌では溶鋼流速で40〜50cm
/秒、2次冷却帯の電磁攪拌では20〜30cm/秒の
攪拌を付与した。
With stirring in the mold, the molten steel flow rate is 40 to 50 cm.
/ Sec, the electromagnetic stirring in the secondary cooling zone was applied at 20 to 30 cm / sec.

【0037】鋳型内電磁攪拌で誘起される下降流を電磁
制動することによる鋳片品質改善効果を把握するため、
連鋳機の片ストランドで制動力を付加し、また、もう一
方のストランドのでは電磁石を切って制動力を付与しな
いで鋳造した。
In order to understand the effect of improving the quality of the cast product by electromagnetically damping the downward flow induced by the electromagnetic stirring in the mold,
Braking force was applied with one strand of the continuous casting machine, and the other strand was cast without cutting the electromagnet to give the braking force.

【0038】さらに本発明を実施したストランドにおい
て鋳型内電磁攪拌と電磁制動を適用した場合に2次冷却
帯の電磁攪拌を適用する水準も設定した。
Further, the level at which the electromagnetic stirring in the secondary cooling zone is applied when the electromagnetic stirring in the mold and the electromagnetic braking are applied to the strand of the present invention is also set.

【0039】尚、凝固組織は鋳片縦断面でエッチプリン
トで評価し、また、鋳片中心部の介在物レベルは棒鋼圧
延した成品中心部を超音波探傷することにより評価し
た。
The solidification structure was evaluated by etch printing in the longitudinal section of the slab, and the inclusion level in the center of the slab was evaluated by ultrasonic flaw detection in the center of the rolled steel product.

【0040】図2にタンディッシュにおける溶鋼加熱度
と厚み比で定義した鋳片上面側等軸晶率の関係について
調査した結果を示す。
FIG. 2 shows the results of an investigation on the relationship between the molten steel heating degree in the tundish and the equiaxed crystal ratio on the upper surface side of the slab defined by the thickness ratio.

【0041】本図より鋳型内電磁攪拌のみを付加した場
合より鋳型下端で電磁制動を付加した場合の方が、さら
に2次冷却帯での電磁攪拌を付加した方が同じ溶鋼加熱
度に対する上面側等軸晶率は向上している。
From this figure, it is seen that when electromagnetic braking is added at the lower end of the mold than when only electromagnetic stirring in the mold is added, electromagnetic stirring in the secondary cooling zone is further added The equiaxed crystal ratio is improved.

【0042】本発明の2法では鋳型内電磁攪拌のみの場
合に対し特に高過熱度側で顕著な等軸晶化促進効果が認
められる。
In the two methods of the present invention, a remarkable effect of promoting equiaxed crystallization is recognized especially on the high superheat side as compared with the case of only electromagnetic stirring in the mold.

【0043】尚、鋳型内と2次冷却帯の2段の電磁攪拌
を適用した場合の上面側等軸晶率は鋳型内電磁攪拌のみ
のときのレベルとほぼ同等か若干改善される程度であ
り、従って、本発明の方法はこの2段電磁攪拌に比べて
もかなり優れた等軸晶化促進効果を有することがわか
る。
When the two-stage electromagnetic stirring in the mold and the secondary cooling zone is applied, the equiaxed crystal ratio on the upper surface side is almost equal to or slightly improved from the level when only electromagnetic stirring in the mold is used. Therefore, it can be seen that the method of the present invention has a considerably excellent effect of promoting equiaxed crystallization even when compared with the two-stage electromagnetic stirring.

【0044】図3には鋳片を棒鋼圧延した成品中心部の
介在物について超音波探傷法で調査した結果を示す。
FIG. 3 shows the results of investigation by ultrasonic flaw detection on inclusions in the center of the product obtained by rolling a cast steel bar.

【0045】本図の縦軸の成品介在物不良指数とは許容
レベルを越える大きさの介在物が存在した成品の割合に
対応させた指数であり、指数が大きいほど介在物レベル
が悪いことを示している。
The product inclusion defect index on the vertical axis of this figure is an index corresponding to the ratio of products in which inclusions having a size exceeding the allowable level exist. The larger the index, the worse the inclusion level. Shows.

【0046】本図より本発明を適用し、鋳型内電磁攪拌
による下降流を抑制した場合はしない場合に比べ成品中
心部介在物レベルは向上している。
From the figure, the level of inclusions at the center of the product is improved compared to the case where the present invention is applied and the downward flow due to electromagnetic stirring in the mold is suppressed.

【0047】[0047]

【発明の効果】以上詳述したように、本発明を適用する
ことにより炭素鋼鋳片の上面側等軸晶率は大幅に向上
し、バラツキも減少する結果、中心偏析やセンターポロ
シティーが減少し、鋳片中心部の介在物レベルも向上す
る結果、鋳片内質は大幅に改善される。
As described in detail above, by applying the present invention, the equiaxed crystal ratio on the upper surface side of the carbon steel slab is greatly improved and the variation is reduced, resulting in reduction of center segregation and center porosity. However, as a result of the inclusion level at the center of the slab also increasing, the quality of the slab is greatly improved.

【0048】一方、本発明により目標等軸晶率を確保す
るためにTD溶鋼過熱度を厳しく下げる必要がなくな
り、従来等軸晶確保のため実施していた低温鋳造で発生
するノズル詰りや介在物レベルの劣化も回避され、一層
の操業安定および鋳片品質の改善が図られる。
On the other hand, according to the present invention, it is not necessary to severely lower the superheat degree of TD molten steel in order to secure the target equiaxed crystal ratio, and nozzle clogging or inclusions generated in the low temperature casting which has been conventionally carried out to secure equiaxed crystal. Level deterioration is also avoided, and further stable operation and improved slab quality are achieved.

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

【図1】実機試験における本発明の実施態様を示す立面
説明図である。
FIG. 1 is an elevational view showing an embodiment of the present invention in an actual machine test.

【図2】タンディッシュの溶鋼加熱度と鋳片上面側等軸
晶率の関係について調査した結果であり、本発明の等軸
晶化促進効果を示す図である。
FIG. 2 is a diagram showing the results of an examination of the relationship between the degree of heating of molten steel in a tundish and the equiaxed crystal ratio of the upper surface of the slab, showing the effect of promoting equiaxed crystallization of the present invention.

【図3】成品中心部の介在物レベルを調査した結果であ
り、本発明による鋳片中心部の介在物レベルの改善効果
を示す図である。
FIG. 3 is a result of investigating the inclusion level at the center of the product, showing the effect of improving the inclusion level at the center of the slab according to the present invention.

【符号の説明】[Explanation of symbols]

1 タンディッシュ 2 モールド 3 鋳型内電磁攪拌装置 4 静磁場付加用電磁石 5 2次冷却帯 6 2次冷却帯の電磁攪拌装置 1 Tundish 2 Mold 3 Electromagnetic stirrer in mold 4 Electromagnet for static magnetic field addition 5 Secondary cooling zone 6 Electromagnetic stirrer for secondary cooling zone

Claims (4)

【特許請求の範囲】[Claims] 【請求項1】 連続鋳造法により鋳片を製造するに際
し、鋳型内の溶鋼に磁場を作用させて溶鋼に鋳造軸まわ
りの攪拌流を発生させるとともに、前記磁場作用位置よ
り下流位置で溶鋼に磁場を作用させて該位置における前
記攪拌に伴う下降流を制動することを特徴とする連鋳鋳
片の内質改善方法。
1. When manufacturing a slab by a continuous casting method, a magnetic field is applied to the molten steel in the mold to generate a stirring flow around the casting axis in the molten steel, and a magnetic field is applied to the molten steel at a position downstream from the magnetic field acting position. Is applied to stop the downward flow associated with the stirring at the position, thereby improving the internal quality of the continuous cast slab.
【請求項2】 連続鋳造法により鋳片を製造するに際
し、鋳型内の溶鋼に磁場を作用させて溶鋼に鋳造軸まわ
りの攪拌流を発生させるとともに、前記磁場作用位置よ
り下流位置で溶鋼に磁場を作用させて該位置における前
記攪拌に伴う下降流を制動し、さらに前記制動用磁場作
用位置より下流位置で溶鋼に磁場を作用させて溶鋼に鋳
造軸まわりの攪拌流を発生させることを特徴とする連鋳
鋳片の内質改善方法。
2. When producing a slab by a continuous casting method, a magnetic field is applied to the molten steel in the mold to generate a stirring flow around the casting axis in the molten steel, and a magnetic field is applied to the molten steel at a position downstream from the magnetic field acting position. Is applied to brake the downward flow associated with the stirring at the position, and a magnetic field is applied to the molten steel at a position downstream from the braking magnetic field application position to generate an agitated flow around the casting axis in the molten steel. Method for improving the internal quality of continuous cast slabs.
【請求項3】 連続鋳造機において、鋳型内溶鋼に鋳造
軸まわりの攪拌流を発生させる磁場発生装置と、前記攪
拌用磁場発生装置位置より下流位置に該位置における前
記攪拌に伴う溶鋼の下降流を制動する磁場発生装置とで
構成したことを特徴とする連続鋳造機の溶鋼流制御装
置。
3. In a continuous casting machine, a magnetic field generator for generating a stirring flow around the casting axis in molten steel in a mold, and a downward flow of molten steel accompanying the stirring at a position downstream of the position of the stirring magnetic field generator. A molten steel flow control device for a continuous casting machine, comprising:
【請求項4】 連続鋳造機において、鋳型内溶鋼に鋳造
軸まわりの攪拌流を発生させる磁場発生装置と、前記攪
拌用磁場発生装置位置より下流位置に該位置における前
記攪拌に伴う溶鋼の下降流を制動する磁場発生装置と、
さらに前記制動用磁場発生装置位置より下流位置に溶鋼
に鋳造軸まわりの攪拌流を発生させる磁場発生装置とで
構成したことを特徴とする連続鋳造機の溶鋼流制御装
置。
4. In a continuous casting machine, a magnetic field generator for generating a stirring flow around the casting axis in molten steel in a mold, and a downward flow of molten steel accompanying the stirring at a position downstream of the position of the stirring magnetic field generator. A magnetic field generator for braking the
A molten steel flow control device for a continuous casting machine, further comprising a magnetic field generation device for generating a stirring flow around the casting axis in the molten steel at a position downstream of the braking magnetic field generation device position.
JP04764092A 1992-02-04 1992-02-04 Method and apparatus for improving internal quality of continuous cast slab Expired - Lifetime JP3180164B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP04764092A JP3180164B2 (en) 1992-02-04 1992-02-04 Method and apparatus for improving internal quality of continuous cast slab

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP04764092A JP3180164B2 (en) 1992-02-04 1992-02-04 Method and apparatus for improving internal quality of continuous cast slab

Publications (2)

Publication Number Publication Date
JPH05212511A true JPH05212511A (en) 1993-08-24
JP3180164B2 JP3180164B2 (en) 2001-06-25

Family

ID=12780844

Family Applications (1)

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

Country Link
JP (1) JP3180164B2 (en)

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Publication number Priority date Publication date Assignee Title
CN103506589A (en) * 2012-06-20 2014-01-15 鞍钢股份有限公司 Method for improving isometric crystal ratio of high-carbon steel billet
CN107214322A (en) * 2017-04-17 2017-09-29 上海大学 Magnetostatic field composite rotating magnetic field homogenizes the method and its device of large-sized casting ingot solidified structure
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CN110576163A (en) * 2019-09-28 2019-12-17 江苏联峰能源装备有限公司 method for producing high-carbon manganese-chromium steel by large-section continuous casting round billet
CN110576163B (en) * 2019-09-28 2021-07-20 江苏联峰能源装备有限公司 Method for producing high-carbon manganese-chromium steel by large-section continuous casting round billet
CN117644188A (en) * 2023-12-12 2024-03-05 北京科技大学 Method for improving quality of ultra-thick plate blank
CN117644188B (en) * 2023-12-12 2024-06-04 北京科技大学 Method for improving quality of ultra-thick plate blank

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