JP2964888B2 - Continuous casting method - Google Patents

Continuous casting method

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Publication number
JP2964888B2
JP2964888B2 JP27640894A JP27640894A JP2964888B2 JP 2964888 B2 JP2964888 B2 JP 2964888B2 JP 27640894 A JP27640894 A JP 27640894A JP 27640894 A JP27640894 A JP 27640894A JP 2964888 B2 JP2964888 B2 JP 2964888B2
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Japan
Prior art keywords
reduction
rolling
slab
segregation
solid
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JPH08132204A (en
Inventor
晃三 太田
章裕 山中
好徳 谷澤
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住友金属工業株式会社
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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、鋼の連続鋳造におい
て、完全に凝固する前の鋳片に軽圧下を加えて鋳片の中
心偏析を防止する連続鋳造方法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting method for preventing the center segregation of a slab by applying light pressure to the slab before it is completely solidified in continuous casting of steel.
【0002】[0002]
【従来の技術】連続鋳造法で鋳片を製造する場合には、
しばしば、中心偏析と呼ばれる内部欠陥が問題となる。
この中心偏析は、鋳片の厚み中心部(最終凝固部)で
C、S、P、Si、Mnなどの溶鋼成分が正偏析する現象で
ある。中心偏析は、靱性の低下や水素誘起割れの原因と
なるので、特に厚板用素材においては深刻な問題を惹起
する。
2. Description of the Related Art When producing a slab by a continuous casting method,
Often, internal defects called center segregation are problematic.
The center segregation is a phenomenon in which molten steel components such as C, S, P, Si, and Mn are positively segregated in a thickness center portion (final solidified portion) of a slab. The center segregation causes a decrease in toughness and hydrogen-induced cracking, and causes a serious problem particularly in a material for a thick plate.
【0003】中心偏析は、凝固末期におけるデンドライ
トの樹間に残る溶鋼がバルジングあるいは凝固収縮等の
原因により、マクロ的に移動することと、前記の成分が
濃化した溶鋼が局部的に集積するために生じることがわ
かっている。この中心偏析の防止対策としては、凝固先
端部付近を何らかの方法で圧下することにより、末期凝
固部の凝固収縮分を補償して濃化溶鋼の流動を抑制する
方法が有効とされ、種々の思想に基づく方法が提案され
てきた。
The central segregation is caused by the fact that molten steel remaining between dendrite trees at the end of solidification moves macroscopically due to bulging or solidification shrinkage, and that the molten steel in which the above-mentioned components have been concentrated is locally accumulated. Is known to occur. As a countermeasure to prevent this center segregation, a method of suppressing the flow of concentrated molten steel by compensating for the solidification shrinkage of the terminal solidification part by reducing the vicinity of the solidification tip by some method has been considered effective. Have been proposed.
【0004】上記の圧下による中心偏析の改善程度と、
単位時間あるいは単位鋳造方向長さ当たりの圧下量(以
下、単に「圧下量」と記す)および圧下時期との間には
明確な相関があり、圧下量と圧下時期に関する定量的な
検討もなされている。
[0004] The degree of improvement of the center segregation due to the above-described reduction,
There is a clear correlation between the amount of reduction per unit time or the length in the unit casting direction (hereinafter simply referred to as "reduction amount") and the reduction timing. Quantitative studies have been made on the reduction amount and the reduction timing. I have.
【0005】例えば、特公昭59−39225 号公報には、タ
ンディッシュ内の溶鋼過熱度を30〜70℃に調整し、か
つ、クレーターエンド(未凝固部の先端)近傍で 0.5〜
2.0mm/m の圧下を加える連続鋳造方法が示されている。
For example, Japanese Patent Publication No. 59-39225 discloses that the degree of superheat of molten steel in a tundish is adjusted to 30 to 70 ° C.
A continuous casting method with a 2.0 mm / m reduction is shown.
【0006】また、特公平5−30548 号公報には、鋳片
の中心部が液相線温度となる時点から、流動限界固相率
になるまでの時期とそれ以後の凝固時期の圧下量を調整
する方法が提案されている。
[0006] Japanese Patent Publication No. 5-30548 discloses a reduction in the solidification time from the time when the center of the slab reaches the liquidus temperature to the time when the flow limit solid phase ratio is reached. Adjustment methods have been proposed.
【0007】しかし、これらの方法においては、クレー
ターエンド近傍あるいは鋳片の中心部が流動限界固相率
となるまでの時期の圧下量が一定であるから、圧下不足
や過圧下を生じやすいという欠点がある。それは以下の
理由による。
However, in these methods, since the amount of reduction in the period near the crater end or in the center of the slab until the flow limit solid phase ratio is constant is constant, insufficient reduction or excessive reduction is likely to occur. There is. It is for the following reasons.
【0008】後に詳しく説明するように、設定圧下量が
固液界面に伝わる割合 (以下、「圧下効率(α)」と記
す) は、鋳造下流側に向かって小さくなる。従って、同
じ圧下量を表面から加えても、固液界面に伝わる圧下量
は凝固時期で変わってくる。
As will be described in detail later, the rate at which the set reduction amount is transmitted to the solid-liquid interface (hereinafter referred to as “reduction efficiency (α)”) decreases toward the downstream side of casting. Therefore, even if the same amount of reduction is applied from the surface, the amount of reduction transmitted to the solid-liquid interface changes at the time of solidification.
【0009】即ち、任意位置の凝固収縮分を基準にした
場合、それより上流側では過圧下になり、それより下流
側では圧下不足になる。前記の公報等に開示される方法
における如く、長い範囲にわたって一定の圧下量で圧下
を加えると、トータルで過圧下や圧下不足を誘発しやす
いのである。圧下不足では当然に中心偏析防止の効果が
小さく、一方、過圧下になると逆V偏析が生じる。
That is, when the coagulation contraction amount at an arbitrary position is used as a reference, the pressure is excessively increased on the upstream side and insufficiently reduced on the downstream side. As in the methods disclosed in the above-mentioned publications and the like, when a reduction is applied with a constant reduction amount over a long range, it is easy to induce overpressure or insufficient reduction in total. If the reduction is insufficient, the effect of preventing the center segregation is of course small. On the other hand, if the reduction is excessive, reverse V segregation occurs.
【0010】上記のような問題点に対して、特開平3−
90263 号公報、特公平5−73506 号公報および特公平5
−73507 号公報には、鋳造下流側に向かうほど圧下速度
を大きくしていく連続鋳造方法が示されている。しか
し、これらの方法にも未だ次のような問題点が残る。即
ち、特開平3−90263 号公報に開示されている方法は、
圧下速度の増加条件の範囲が圧下不足となる条件から過
圧下となる条件まで包含しており、中心偏析の改善効果
が安定して得られないと考えられる。
To solve the above problems, Japanese Patent Laid-Open No.
No. 90263, Japanese Patent Publication No. 5-73506 and Japanese Patent Publication No. 5
No. 73507 discloses a continuous casting method in which the rolling speed is increased toward the downstream side of casting. However, these methods still have the following problems. That is, the method disclosed in JP-A-3-90263 is
The range of the condition for increasing the rolling speed includes the condition of insufficient rolling to the condition of excessive rolling, and it is considered that the effect of improving center segregation cannot be stably obtained.
【0011】特公平5−73506 号公報に開示される方法
では、中心偏析の改善を安定して達成するための圧下量
に関する具体的な条件が明らかでない。
In the method disclosed in Japanese Patent Publication No. 5-73506, specific conditions regarding the amount of reduction for stably improving the center segregation are not clear.
【0012】特公平5−73507 号公報の方法では、ロー
ル反力による数値限定がなされているが、ロール反力と
適正圧下量との関係が記述されておらず、凝固収縮によ
る流動防止のための考え方が明らかにされていない。さ
らに、上記の3つの公報に示される方法では、鋳片温度
分布の圧下条件に及ぼす影響が考慮されていないという
に共通の問題点がある。
In the method disclosed in Japanese Patent Publication No. 5-73507, the numerical value is limited by the roll reaction force. However, the relationship between the roll reaction force and the appropriate rolling reduction is not described, and in order to prevent flow due to solidification shrinkage. The idea of is not disclosed. Furthermore, the methods disclosed in the above three publications have a common problem in that the influence of the slab temperature distribution on the rolling conditions is not taken into account.
【0013】[0013]
【発明が解決しようとする課題】凝固末期における軽圧
下が連続鋳造鋳片の中心偏析の軽減に有効であることは
知られているが、従来の方法では適切な圧下量の選定が
困難で圧下不足あるいは過圧下により中心偏析の改善が
充分でないか、むしろ中心偏析が増加することさえあっ
た。
It is known that light reduction at the end of solidification is effective in reducing the center segregation of a continuous cast slab, but it is difficult to select an appropriate reduction amount by the conventional method, and the reduction is difficult. Insufficient or excessive pressure has not improved the center segregation sufficiently, or even increased the center segregation.
【0014】本発明の目的は、鋳造速度や二次冷却条件
(鋳片表面温度、ひいては鋳片断面の温度勾配)等の鋳
造条件の変化および鋳片内部の凝固の進展(未凝固厚み
の変化)とかかわりなく、所定の条件で圧下を施し、し
かも中心偏析の原因となる収縮流動を従来方法以上に効
果的に防止することができる連続鋳造方法を提供するこ
とにある。
An object of the present invention is to change casting conditions such as casting speed and secondary cooling conditions (slab slab surface temperature, and thus temperature gradient of slab slabs) and the progress of solidification inside the slab (change in unsolidified thickness). Regardless of the present invention, it is an object of the present invention to provide a continuous casting method capable of performing reduction under predetermined conditions and effectively preventing shrinkage flow which causes center segregation as compared with the conventional method.
【0015】[0015]
【課題を解決するための手段】本発明は、下記(1) およ
び(2) の連続鋳造方法を要旨とする。
The gist of the present invention is a continuous casting method of the following (1) and (2).
【0016】(1) 連続鋳造鋳片の末期凝固部で軽圧下を
加える連続鋳造方法において、圧下開始点を 0.0≦fs≦
0.2 の範囲とし、圧下終了点を 0.8≦fs≦1.0 とし、そ
の間において連続圧下を行い、かつ、流動限界固相率を
基準とした固液界面における圧下量の総和を 0.6〜1.4m
m 以下とすることを特徴とする連続鋳造方法。
(1) In a continuous casting method in which a light reduction is applied at the final solidification part of a continuous cast slab, the rolling start point is set to 0.0 ≦ fs ≦
0.2, and the rolling end point is set to 0.8 ≦ fs ≦ 1.0, during which continuous rolling is performed, and the total amount of rolling at the solid-liquid interface based on the flow limit solid fraction is 0.6 to 1.4 m.
m or less.
【0017】(2) 連続鋳造鋳片の末期凝固部で軽圧下を
加える連続鋳造方法において、圧下開始点を 0.0≦fs≦
0.2 の範囲とし、圧下終了点を 0.8≦fs≦1.0 とし、そ
の間において連続圧下を行い、かつ、流動限界固相率を
基準とした固液界面における圧下速度を0.15〜0.3mm/mi
n 以下とすることを特徴とする連続鋳造方法。
(2) In a continuous casting method in which a light reduction is applied at the final solidification part of a continuous cast slab, the rolling start point is set to 0.0 ≦ fs ≦
0.2, the rolling end point is set to 0.8 ≦ fs ≦ 1.0, during which continuous rolling is performed, and the rolling speed at the solid-liquid interface based on the flow limit solid fraction is 0.15 to 0.3 mm / mi.
A continuous casting method characterized by being not more than n.
【0018】上記(1) および(2) の方法において、fsは
鋳片の厚み中心固相率である。また、上記の「固液界
面」とは流動限界固相率(約 0.7〜0.8 )に達した鋳片
内部の位置を意味する。
In the above methods (1) and (2), fs is the thickness center solid fraction of the slab. The above-mentioned "solid-liquid interface" means the position inside the slab which has reached the flow limit solid fraction (about 0.7 to 0.8).
【0019】図2は、凝固シェル4の内部に未凝固部3
が存在する鋳片を圧下した場合の固液界面5の圧下速
度、圧下効率等のパラメータの定義を説明するための鋳
片断面模式図である。図示の10の位置でピンチロールに
よる圧下を加えたとき、図示の各記号は次のように定義
される。
FIG. 2 shows that the unsolidified portion 3 is formed inside the solidified shell 4.
FIG. 4 is a schematic cross-sectional view of a slab for explaining definitions of parameters such as a rolling speed and a rolling efficiency of a solid-liquid interface 5 when a slab having slabs is reduced. When a reduction by a pinch roll is applied at a position 10 shown in the figure, each symbol shown in the figure is defined as follows.
【0020】 δS :表面圧下量 (mm) L :圧下を受けた距離( m ) δI :固液界面圧下量 (mm) VC :鋳造速度 ( m/min ) ここで、固液界面の圧下速度をRI (mm/min )とすると RI =(δI / L )×VC である。即ち、固液界面の圧下速度RI は、固液界面に
おける単位時間当たりの圧下量として求められる。ま
た、圧下効率αは、 α=(δI /δS ) で表される。なお、δI は、例えば、メニスカスからFe
SやPbのような比重が大きく固液界面に堆積するトレー
サーを添加し、その移動を追跡することによって測定で
きる。
Δ S : Surface reduction amount (mm) L: Distance subjected to reduction (m) δ I : Solid-liquid interface reduction amount (mm) V C : Casting speed (m / min) If the reduction speed is R I (mm / min), R I = (δ I / L) × V C. In other words, reduction speed R I of the solid-liquid interface is determined as reduction amount per unit time in the solid-liquid interface. The rolling efficiency α is expressed by α = (δ I / δ S ). Incidentally, [delta] I, for example, Fe meniscus
It can be measured by adding a tracer such as S or Pb which has a large specific gravity and deposits on the solid-liquid interface, and tracks its movement.
【0021】[0021]
【作用】従来から中心偏析の改善のためには最適な軽圧
下量が存在することは知られており、しかも、その圧下
量は、鋳片表面温度(言い換えれば鋳片内部の温度分
布)、凝固の程度によって変動することも経験的にわか
っていた。従って、未凝固部を持つ鋳片の圧下に際して
は鋳片の凝固の程度、2次冷却条件(鋳片内温度勾配)
に応じて圧下条件を変更しなければならないものと考え
られていた。
It has been known that there is an optimum light reduction amount for improving the center segregation, and the reduction amount depends on the slab surface temperature (in other words, the temperature distribution inside the slab), It was also empirically found to vary with the degree of coagulation. Therefore, when rolling down a slab having an unsolidified portion, the degree of solidification of the slab, secondary cooling conditions (temperature gradient in the slab)
It was thought that the rolling conditions had to be changed according to the conditions.
【0022】本発明者は様々な鋳造条件に対応可能であ
る軽圧下条件の指標を提供し、かつ中心偏析改善のため
の凝固末期軽圧下を従来より有効に行うために、固液界
面の圧下挙動に着目して研究をすすめた。
The inventor of the present invention has provided an index of light reduction conditions capable of coping with various casting conditions, and has been required to reduce the solid-liquid interface in order to more effectively perform the final solidification light reduction for improving center segregation. Focusing on behavior, he studied.
【0023】図5は鋼の連続鋳造で未凝固部分を含む鋳
片に圧下を加えた場合の鋳片表面圧下速度RS (mm/min)
と中心偏析の関係を調べた結果を示す図である。ここで
は圧下中の鋳片表面温度が 700〜900 ℃の場合と 900〜
1000℃の場合の2つに分けて整理してある。なお、中心
偏析は後述する実施例に示す炭素偏析度 (C/CO )で
評価した。
FIG. 5 shows the slab surface reduction speed R S (mm / min) when the slab including the unsolidified portion is subjected to reduction in continuous casting of steel.
FIG. 4 is a diagram showing the result of examining the relationship between and center segregation. Here, the case where the slab surface temperature during rolling is 700-900 ° C and 900-900 ° C
It is divided into two cases for 1000 ° C. The center segregation was evaluated based on the degree of carbon segregation (C / C O ) shown in Examples described later.
【0024】図5に示すように鋳片表面温度が高くなる
ほど、偏析度 (C/CO ) を低くするための表面圧下速
度 (RS ) を大きくする必要がある。
As shown in FIG. 5, as the surface temperature of the slab becomes higher, it is necessary to increase the surface rolling speed (R S ) for lowering the degree of segregation (C / C O ).
【0025】図6(b)は同(a)に示すような3種の
圧下パターンで軽圧下を行ったときの中心偏析発生状況
の調査結果である。図6(a)に示すパターン1、即
ち、凝固の進行と共に圧下勾配を大きくしていく圧下形
態の時に最も中心偏析の改善程度が大きい。これらの結
果は、鋳片内部の温度分布、凝固の進行程度に応じた圧
下量を選定する必要があることを意味する。
FIG. 6 (b) shows the results of an investigation of the state of occurrence of center segregation when light reduction was performed in three types of reduction patterns as shown in FIG. 6 (a). In the pattern 1 shown in FIG. 6A, that is, in the rolling mode in which the rolling gradient is increased with the progress of solidification, the degree of improvement of the center segregation is greatest. These results indicate that it is necessary to select a reduction amount according to the temperature distribution inside the slab and the degree of progress of solidification.
【0026】図5および図6のような結果が生じる理由
は以下のように考えられる。
The reason why the results shown in FIGS. 5 and 6 are generated is considered as follows.
【0027】鋳片をロールにより圧下する場合、表面か
ら加えた圧下量はそのまま固液界面に伝播するわけでは
なく、表面圧下量と固液界面に伝わる圧下量の比(前記
の圧下効率α)は 1.0以下である。これは、鋳片未凝固
部の変形抵抗、流動抵抗等のために、表面圧下量が鋳片
の幅拡がりと先進等に消費されるからである。
When the slab is rolled down by a roll, the amount of reduction applied from the surface does not propagate to the solid-liquid interface as it is, but the ratio of the amount of surface reduction to the amount of reduction transmitted to the solid-liquid interface (the aforementioned reduction efficiency α). Is less than or equal to 1.0. This is because the surface reduction amount is consumed for the expansion of the width of the slab, the advance of the slab, etc. due to deformation resistance, flow resistance, etc. of the unsolidified portion of the slab.
【0028】図7にメニスカスからの距離、即ち、鋳造
進行方向の距離と圧下効率αの関係の一例を示す。α
は、先に説明したように図2に示す方法で求めた。
FIG. 7 shows an example of the relationship between the distance from the meniscus, that is, the distance in the casting direction and the rolling efficiency α. α
Was determined by the method shown in FIG. 2 as described above.
【0029】本発明者は、この実験データか、有限要素
法による応力解析モデルを構築し、様々な条件での固液
界面の圧下挙動を推算した。
The inventor constructed a stress analysis model based on the experimental data or the finite element method and estimated the rolling behavior of the solid-liquid interface under various conditions.
【0030】凝固の進行と共に、未凝固部の抵抗が固液
界面に及ぼす影響が大きくなるため、αは小さくなる。
また、鋳片温度が高くなるほど(即ち、鋳片内部の温度
勾配が小さいほど)、凝固シェル剛性は小さく、表面圧
下量が鋳片の幅拡がりと先進に消費されやすくなるため
にαは小さくなる。従って、仮に一定の圧下勾配で鋳片
を圧下しても、図8に示すように凝固時期(メニスカス
からの距離)および鋳片内温度勾配(鋳片表面温度)に
より固液界面に伝播する圧下量が異なることになる。
As the solidification proceeds, the influence of the resistance of the unsolidified portion on the solid-liquid interface increases, so that α decreases.
Also, the higher the slab temperature (ie, the smaller the temperature gradient inside the slab), the lower the solidified shell stiffness, and the smaller the α because the surface reduction is more likely to be consumed in the wider and more advanced slab. . Therefore, even if the slab is reduced with a constant reduction gradient, as shown in FIG. 8, the reduction propagated to the solid-liquid interface due to the solidification time (distance from the meniscus) and the temperature gradient in the slab (slab surface temperature). The amount will be different.
【0031】このような結果から本発明者らは、凝固の
程度、鋳片内温度分布が異なっても普遍的な整理ができ
るようなパラメーターを追求すべく、独自に、固液界面
における圧下挙動と中心偏析程度の相関を調査したとこ
ろ、以下に記述する現象を見い出し、本発明を完成し
た。
Based on these results, the present inventors independently developed the rolling behavior at the solid-liquid interface in order to pursue parameters that can be universally arranged even if the degree of solidification and the temperature distribution in the slab differ. Investigation of the correlation between and the degree of center segregation revealed the phenomenon described below, and completed the present invention.
【0032】図3は流動限界固相率を基準とした固液界
面に伝播する圧下量の総和ΣδI と炭素偏析度 (C/C
O ) で評価した中心偏析との関係を示したものである。
なお、この図は鋳片表面温度が 750〜1100℃までの広範
囲にわたってのデータを示したものである。
FIG. 3 shows the sum Σδ I of the amount of reduction propagated to the solid-liquid interface based on the flow limit solid fraction and the degree of carbon segregation (C / C
It shows the relationship with the center segregation evaluated in O ).
This figure shows data over a wide range from 750 to 1100 ° C.
【0033】図3には圧下時期を次の4種類に変更した
場合について示した。
FIG. 3 shows the case where the rolling timing is changed to the following four types.
【0034】鋳片の厚み中心固相率 (前記のfs) が
0.0を超えたところから 0.8となるまで連続圧下した場
合(図3の○) 0.2<fs<0.8 の範囲を連続圧下した場合(図3の
△) 0<fsのところからfs=0.5 のところまで連続圧下し
た場合(図3の□) 0<fsのところからfs=1.0 のところまで連続圧下し
た場合(図3の●) なお、図3では固液界面を形成する固相率を流動限界固
相率としている。
The slab thickness center solid phase ratio (the above fs) is
Continuous reduction from the point exceeding 0.0 to 0.8 (○ in Fig. 3) Continuous reduction in the range of 0.2 <fs <0.8 ((in Fig. 3) From 0 <fs to fs = 0.5 Continuous reduction (□ in FIG. 3) Continuous reduction from 0 <fs to fs = 1.0 (● in FIG. 3) In FIG. 3, the solid phase ratio that forms the solid-liquid interface is determined by the flow limit solid. The percentage is assumed.
【0035】図3から明らかなように、鋳片表面温度に
関わらず、ΣδI を 0.6〜1.4 mmの範囲に制御すること
により、中心偏析の大きな改善が得られている。
As is apparent from FIG. 3, the center segregation is largely improved by controlling Σδ I within the range of 0.6 to 1.4 mm regardless of the slab surface temperature.
【0036】上記の結果から、表面温度が広範囲にわた
って異なる多数の鋳片についても、ΣδI という一つの
ファクターで中心偏析を減少させる範囲が確定できるこ
とが明らかであり、このΣδI を用いる本発明の方法
は、従来の鋳片表面における圧下量制御法よりも普遍性
を有することがわかる。
[0036] From the above results, for the number of slab surface temperature is different over a wide range, it is clear that you can determine the range to reduce the center segregation in a factor called Sigma] [Delta] I, the present invention using the Sigma] [Delta] I It can be seen that the method has more universality than the conventional method of controlling the rolling reduction on the slab surface.
【0037】ΣδI は圧下区間中、ほぼ等しい界面圧下
速度RI (mm/min)に配分されることが望ましい。但し、
±20〜30%のバラツキの範囲内で配分されていてもその
区間が連続圧下されていればΣδI の適正制御により中
心偏析の大きな改善が得られる。すなわち、局所的にみ
れば適正範囲からずれていても、圧下範囲トータルでみ
て圧下不足になるか過圧下になるかの判定をすればよい
ということになる。
It is desirable that Σδ I be distributed to substantially equal interfacial reduction speeds R I (mm / min) during the reduction section. However,
It is distributed in the range of ± 20 to 30% of the variation that section significant improvement of center segregation is obtained by proper control of the Sigma] [Delta] I if it is continuous pressure. In other words, even if it deviates from the appropriate range when viewed locally, it is only necessary to determine whether the rolling reduction will be insufficient or excessive under the rolling reduction range as a whole.
【0038】次に、図3を圧下を加える時期(鋳片厚み
中心の固相率fsの範囲)という観点からみて、同一量の
ΣδI で中心偏析を比較した場合、0<fsからfs=0.8
までの範囲を連続圧下した場合 (前記、図3の○印)
と0<fsからfs=1.0 の範囲を連続圧下した場合 (前記
、図3●印) が最も中心偏析が減少している。以下、
0.2<fs<0.8 の範囲を連続圧下した場合 (前記、図
3の△) 、0<fsのところからfs=0.5 のところまで連
続圧下した場合 (前記、図3の□) の順に偏析が大き
くなっている。
Next, from the viewpoint of the timing of applying the reduction (the range of the solid phase ratio fs at the center of the slab thickness) in FIG. 3, when comparing the center segregation with the same amount of Δδ I , 0 <fs to fs = 0.8
In the case of continuous reduction in the range up to (upper circle in Fig. 3)
In the case of continuous reduction in the range of fs = 1.0 from 0 <fs to 0 <fs (the above-mentioned mark ● in FIG. 3), the center segregation is reduced most. Less than,
The segregation increases in the order of continuous reduction in the range of 0.2 <fs <0.8 (above, △ in FIG. 3) and continuous reduction from 0 <fs to fs = 0.5 (□ in FIG. 3). Has become.
【0039】このことは、中心偏析を形成する凝固時期
が固相率fsが0を超え、0.8 となるまでの範囲であるこ
とを意味し、この範囲を確実に適正な界面圧下量で連続
圧下することが重要であることを示している。
This means that the solidification time at which the center segregation is formed is in the range from the solid phase ratio fs exceeding 0 to 0.8, and this range is surely reduced by an appropriate interfacial pressure reduction amount. Indicates that it is important to
【0040】但し、圧下時期を 0.2<fs<0.8 とした
の場合でも、に比べてかなり偏析の改善効果は見られ
ており、圧下が必要な最低限の範囲はこの範囲であると
考えられる。
However, even when the rolling timing is set to 0.2 <fs <0.8, the effect of improving segregation is considerably improved as compared with the case where the rolling timing is set to 0.2 <fs <0.8, and it is considered that the minimum range in which the rolling is required is in this range.
【0041】以上の知見に基づいてなされたのが前記
(1) の発明、すなわち、「圧下開始点を鋳片の厚み中心
固相率が0〜0.2 の範囲とし、圧下終了点を 0.8〜1.0
の範囲とし、その全域において連続圧下を行い、固液界
面における圧下量の総和を 0.6〜1.4 mmとすることを特
徴とする連続鋳造方法」の発明である。
Based on the above findings, the above
The invention of (1), that is, `` the rolling start point is in the range of 0 to 0.2 in the thickness center solid phase ratio of the slab, and the rolling end point is 0.8 to 1.0
And continuous rolling is performed in the entire region, and the total amount of rolling at the solid-liquid interface is set to 0.6 to 1.4 mm.
【0042】次に、前記(2) の発明、即ち、「圧下開始
点を鋳片の厚み中心固相率が0〜0.2 の範囲とし、圧下
終了点を 0.8〜1.0 の範囲とし、その全域において固液
界面における圧下速度が0.15〜0.30mm/minとなる連続圧
下を行うことを特徴とする連続鋳造方法の発明」につい
て説明する。
Next, the invention of the above (2), that is, "the rolling start point is in the range of 0 to 0.2 in the thickness center solid fraction of the slab, the rolling end point is in the range of 0.8 to 1.0, The invention of a continuous casting method characterized in that a continuous reduction at a solid-liquid interface with a reduction speed of 0.15 to 0.30 mm / min is performed ".
【0043】図4は流動限界固相率を基準とした固液界
面に伝播する単位時間当たりの圧下量、即ち前述の界面
圧下速度RI と中心偏析(前記の炭素偏析度、C/
O )の関係についても調査した結果である。
FIG. 4 shows the amount of reduction per unit time propagating at the solid-liquid interface based on the flow limit solid fraction, that is, the above-mentioned interfacial reduction speed R I and the center segregation (the carbon segregation degree, C /
It is also the result of investigation on the relationship of C O ).
【0044】圧下時期は、図3から確定した中心偏析改
善のための最適圧下時期である0<fsのところからfs=
0.8 のところまでの場合について示してある。図4から
明らかなように、固液界面の圧下速度RI にも中心偏析
の改善のための適正範囲が存在する。すなわち、RI
0.15〜0.30mm/minの範囲にあるとき中心偏析の大きな改
善が得られる。
The rolling timing starts from 0 <fs, which is the optimum rolling timing for improving center segregation determined from FIG.
Cases up to 0.8 are shown. As apparent from FIG. 4, the proper range for the solid-liquid pressure rate R I to the improvement of the center segregation of the interface is present. That is, R I
When it is in the range of 0.15 to 0.30 mm / min, a large improvement in center segregation is obtained.
【0045】RI の最適範囲は、鋳片の単位時間当たり
の収縮量と同等から2倍程度までである。すなわち、鋳
片の体積収縮により溶鋼流動とバランスするようなRI
を選定することが重要である。体積収縮量に比較して2
倍程度の過圧下気味の条件でも中心偏析が改善されるの
は、体積収縮以外にもロール間バルジング等、溶鋼流動
の原因となる現象があるため、これを相殺するだけの圧
下を行う必要があるからである。
The optimum range of R I is from the same as the shrinkage per unit time of the slab to about twice. That is, R I that balances the flow of molten steel due to volumetric shrinkage of the slab
It is important to select 2 compared to volume shrinkage
The center segregation is improved even under conditions of about twice the overpressure.Besides volume shrinkage, there are other phenomena that cause molten steel flow, such as bulging between rolls.Therefore, it is necessary to perform reduction only to offset this. Because there is.
【0046】RI が最適範囲より小さい場合は圧下不足
により中心偏析が増大し、一方、最適範囲より大きい場
合は過圧下により(逆v偏析が生じて)やはり中心偏析
が増える。
When R I is smaller than the optimum range, center segregation increases due to insufficient rolling. On the other hand, when R I is larger than the optimum range, center segregation also increases due to over-pressing (reverse v segregation occurs).
【0047】前記(1) の発明の条件と (2)の発明の条件
は両立させることが望ましい。即ち「鋳片の厚み中心の
固相率が0より大きく 0.8以下である範囲の全域におい
て固液界面における圧下速度が0.15〜0.30mm/minとなる
ように、しかも固液界面における圧下量の総和が 0.6〜
1.4mm となるように連続圧下する」のが最も望ましい。
It is desirable that the conditions of the invention (1) and the conditions of the invention (2) are compatible. That is, "the reduction rate at the solid-liquid interface is 0.15 to 0.30 mm / min in the entire range where the solid fraction at the center of the thickness of the slab is greater than 0 and 0.8 or less, and the sum of the reduction amounts at the solid-liquid interface Is 0.6 ~
It is most desirable to continuously reduce the pressure to 1.4 mm. "
【0048】本発明方法はスラブ、ブルーム、ビレット
等の各種形状の鋳片の鋳造に適用可能であり、スラブの
ような偏平比の大きい鋳片においては幅方向のどの位置
にも適用できる。
The method of the present invention can be applied to casting of slabs of various shapes such as slabs, blooms and billets, and can be applied to any position in the width direction of slabs such as slabs having a large aspect ratio.
【0049】[0049]
【実施例1】図1に概略構造を示す連続鋳造機を使用し
て、鋼スラブの連続鋳造を行った。
EXAMPLE 1 Continuous casting of a steel slab was performed using a continuous casting machine having a schematic structure shown in FIG.
【0050】この連鋳機は湾曲半径 12.5mのS型連鋳機
であり、圧下ゾーンの長さは5mである。
This continuous caster is an S-type continuous caster with a radius of curvature of 12.5 m, and the length of the rolling zone is 5 m.
【0051】図1において、浸漬ノズル2から鋳型1に
鋳込まれた溶鋼3はサポートロール群6、圧下ロール群
7、そしてピンチロール8を経て凝固し、引き出され
る。圧下ロール群は複数の圧下ロールで構成され、ロー
ルに与える油圧を制御することにより、圧下量(圧下速
度)の調整ができる。表1に鋳造条件(圧下条件以外)
を、表2および表3に圧下条件を示す。
In FIG. 1, the molten steel 3 cast into the mold 1 from the immersion nozzle 2 is solidified through a support roll group 6, a pressing roll group 7, and a pinch roll 8, and is drawn out. The rolling roll group is composed of a plurality of rolling rolls, and the amount of rolling (rolling speed) can be adjusted by controlling the hydraulic pressure applied to the rolls. Table 1 shows casting conditions (other than rolling down conditions)
Are shown in Tables 2 and 3 below.
【0052】実施例1〜4は本発明(1) の実施例であ
り、鋳片の幅中央部の厚み中心固相率fsが 0.0〜0.8 の
範囲の全域で連続圧下を加え、その間で固液界面で受け
た総圧下量ΣδI が 0.6〜1.4 mmとなるように設定圧下
量を調整した場合である。但し、界面圧下速度RI は必
ずしも、本発明(2) の範囲内には入っていない。
Examples 1 to 4 are examples of the present invention (1), in which continuous reduction is applied over the entire range where the thickness center solid phase ratio fs at the center of the width of the slab is in the range of 0.0 to 0.8. is when the total rolling amount Sigma] [Delta] I received in the liquid interface was adjusted set reduction amount so that 0.6 to 1.4 mm. However, the interface reduction rate R I is not necessarily contains in the range of the present invention (2).
【0053】実施例5〜8は本発明(2) の実施例であ
り、鋳片の幅中央部の厚み中心固相率fsが 0.0〜0.8 ま
での全域で連続圧下を加え、且つ、各固相率区間におけ
る界面圧下速度RI が0.15〜0.30mm/minとなるように設
定圧下量を調整した場合である。
Examples 5 to 8 are examples of the present invention (2), in which a continuous reduction is applied over the entire range of the thickness center solid phase ratio fs of the slab from 0.0 to 0.8, and interfacial pressure rate R I in the phase rate interval is adjusted for setting reduction ratio so that 0.15~0.30mm / min.
【0054】一方、比較例1〜4は従来例として、鋳片
表面の圧下速度RS を制御した場合、比較例5は界面圧
下速度RI がほぼ適正値に制御されているが、圧下時期
が鋳片の厚み中心固相率fsが 0.1〜0.7 の範囲であった
場合、比較例6は界面総圧下量ΣδI が適正値に制御さ
れているが、圧下したのが鋳片の厚み中心固相率fsが0.
3〜0.7 の範囲であった場合である。
On the other hand, in Comparative Examples 1 to 4, as a conventional example, when the rolling speed R S of the slab surface was controlled, and in Comparative Example 5, the interfacial rolling speed R I was controlled to a substantially appropriate value. If there thickness center solid phase ratio fs of the slab is in the range of 0.1 to 0.7, Comparative example 6 is the interface total rolling amount Sigma] [Delta] I is controlled to a proper value, that was reduction of the slab thickness center Solid phase ratio fs is 0.
It is the case where it was in the range of 3 to 0.7.
【0055】[0055]
【表1】 [Table 1]
【0056】[0056]
【表2】 [Table 2]
【0057】[0057]
【表3】 [Table 3]
【0058】表4に実施例および比較例における中心偏
析の調査結果を示す。中心偏析の程度を示す炭素偏析度
は、鋳片幅中央部の中心偏析部の炭素濃度 (C) を発光
分析法で10点測定し、その中のピーク値と鋼の平均濃度
(CO ) との比(C/CO )として評価した。
Table 4 shows the results of investigation of center segregation in the examples and comparative examples. The degree of carbon segregation, which indicates the degree of center segregation, is measured by measuring the carbon concentration (C) of the center segregation part at the center of the slab width at 10 points by emission spectrometry, and the peak value and the average concentration
It was evaluated as (C O) and a ratio of (C / C O).
【0059】更に、鋳片の圧下状態を推定するために、
鋳片幅中央部の偏析形態を調査した。V偏析は圧下不足
の状態に, 逆V偏析は過圧下の状態に対応すると考えら
れる。従って、偏析形態はV偏析でも逆V偏析でもない
のが好ましい。
Further, in order to estimate the rolling state of the slab,
The segregation form at the center of the slab width was investigated. It is considered that V segregation corresponds to the state of insufficient reduction and reverse V segregation corresponds to the state of overpressure. Therefore, the segregation form is preferably neither V segregation nor reverse V segregation.
【0060】実施例1〜4は様々な鋳片表面温度(Tsu)
の範囲で界面総圧下量ΣδI を適正値に制御したもので
あるが、この場合も炭素偏析度(C/CO ) は1.10以下
と非常に低位であり、鋳片縦断面にはV偏析も逆V偏析
も観察されなかった。
Examples 1 to 4 show various slab surface temperatures (Tsu).
But is obtained by controlling the interfacial total rolling amount Sigma] [Delta] I to an appropriate value in a range of, in this case carbon segregation ratio also (C / C O) is very low and 1.10 or less, V segregation in the slab longitudinal section No reverse V segregation was observed.
【0061】実施例5〜8は、様々な圧下ゾーン入側の
鋳片表面温度(Tsu) の範囲で界面圧下速度RI を適正値
に制御したものであるが、いずれの場合も炭素偏析度
(C/CO ) は1.10以下と低位の偏析程度を示してい
た。また、鋳片縦断面にはV偏析も逆V偏析も観察され
ず、圧下不足でも過圧下でもない良好な圧下状態になっ
ていることが推察された。
[0061] Examples 5-8, which is obtained by controlling the interfacial pressure rate R I to an appropriate value in a range of different pressure zones entry side of the slab surface temperature (Tsu), either case the carbon segregation ratio (C / C O ) showed a low degree of segregation of 1.10 or less. In addition, neither V segregation nor reverse V segregation was observed in the vertical section of the slab, and it was inferred that a good rolling state was obtained, which was neither insufficient rolling reduction nor excessive pressure reduction.
【0062】実施例1〜8において、広い鋳片表面温度
範囲にわたって低位の中心偏析程度が得られたのは、固
液界面圧下速度、または固液界面圧下量の総計が適正範
囲になるように表面圧下速度を設定したからである。
In Examples 1 to 8, the reason why a low degree of center segregation was obtained over a wide range of slab surface temperature was that the rate of the solid-liquid interfacial pressure reduction or the total amount of the solid-liquid interfacial pressure reduction was within an appropriate range. This is because the surface reduction speed was set.
【0063】一方、比較例1〜2は、鋳片表面からの圧
下速度RS を一定値にしたものであるが、いずれも炭素
偏析度は実施例と比較して高位であった。比較例1は、
fsが0.4 以上の位置での界面圧下速度RI が適正値より
小さく、界面総圧下量ΣδIも適正値より小さかったた
め、圧下不足でV偏析が生じ中心偏析が悪化した。
On the other hand, in Comparative Examples 1 and 2, the rolling speed R S from the slab surface was kept constant, but the degree of carbon segregation was higher than that of the Examples. Comparative Example 1
fs is smaller than the appropriate value interfacial pressure rate R I is at the position of 0.4 or more, because the interface total rolling amount Sigma] [Delta] I also smaller than the proper value, the V segregation at a reduction shortage center segregation caused deteriorates.
【0064】比較例2はfs= 0.0〜0.7 の範囲の界面圧
下速度RI が大きく、界面総圧下量ΣδI も適正値より
大きかったため、過圧下により中心偏析が悪化した。こ
のように、fs= 0.0〜0.8 の範囲の圧下を、RS 一定の
条件で行うと圧下不足や過圧下を生じ易く、中心偏析の
改善は得られない。
[0064] Comparative Example 2 is large in surface pressure rate R I in the range of fs = from .0 to 0.7, since larger than the interface total rolling amount Sigma] [Delta] I also proper value, the center segregation was exacerbated by excessive pressure. As described above, when the reduction in the range of fs = 0.0 to 0.8 is performed under the condition of the constant R S , the reduction is likely to be insufficient or the overpressure is reduced, and the improvement of the center segregation cannot be obtained.
【0065】比較例3〜4は、鋳片表面からの圧下効率
が鋳造下流側になるに従って小さくなることを意識し
て、表面圧下速度RS を鋳造下流側にいくにつれて大き
くしたものであるが、炭素偏析度は実施例と比較して高
位であった。
In Comparative Examples 3 and 4, the surface reduction speed R S was increased toward the downstream side of the casting in consideration of the fact that the rolling efficiency from the surface of the slab became smaller toward the downstream side of the casting. The degree of carbon segregation was higher than that of the examples.
【0066】比較例3は、圧下範囲全域にわったて界面
圧下速度RI が適正値に入らず、界面総圧下量ΣδI
適正値より小さかったため、圧下不足(V偏析)で中心
偏析が悪化した。
In Comparative Example 3, since the interfacial rolling speed R I did not enter the proper value over the entire rolling range and the interfacial total rolling amount Σδ I was smaller than the proper value, the center segregation was caused by insufficient rolling (V segregation). It got worse.
【0067】比較例4は、fsが 0.4以上の位置での界面
圧下速度RI が適正値よりも大きく、界面総圧下量Σδ
I も適正値より大きかったために、過圧下により中心偏
析が悪化した。このように、鋳造下流側になるほど表面
圧下速度RS を大きくしても、界面圧下速度RI あるい
は界面総圧下量ΣδI が適正な値になるように圧下量を
設定しないと、中心偏析の改善は得られない。
In Comparative Example 4, the interface reduction speed R I at a position where fs was 0.4 or more was larger than an appropriate value, and the total interface reduction amount Δδ
Since I was also larger than the appropriate value, center segregation worsened due to overpressure. Thus, increasing the surface pressure rate R S as will cast downstream, it is not set the reduction amount so interfacial pressure rate R I or surfactants total rolling amount Sigma] [Delta] I is a proper value, the center segregation No improvement is obtained.
【0068】比較例5では、fs= 0.1〜0.7 の範囲の界
面圧下速度RI を適正値に制御したがfs= 0.0〜0.1 、
fs= 0.7〜0.8 の範囲が圧下されていないため、炭素偏
析度は実施例と比較して高く、縦断面の偏析形態も圧下
不足を示すV偏析であった。
[0068] Comparative Example In 5, fs = the range of 0.1 to 0.7 interfacial pressure rate was controlled R I to a proper value fs = 0.0 to 0.1,
Since the range of fs = 0.7 to 0.8 was not reduced, the degree of carbon segregation was higher than that of the example, and the segregation form of the longitudinal section was V segregation indicating insufficient rolling reduction.
【0069】比較例6は fs= 0.3〜0.7 の範囲でのみ
圧下し, 界面総圧下量ΣδI を適正値に制御したもので
あるが、fs= 0.0〜0.30、fs= 0.7〜0.8 の範囲を圧下
していないために、fs= 0.3〜0.7 の界面圧下速度が大
きくなってしまい、この範囲で過圧下になったため、炭
素偏析度は高かった。比較例5、6の結果から、fs=0.
0〜0.8 の範囲の全域において適切に連続圧下しないと
中心偏析の改善は得られないことがわかる。
[0069] Comparative Example 6 were pressure only in the range of fs = 0.3 to 0.7, but is obtained by controlling the interfacial total rolling amount Sigma] [Delta] I to a proper value, fs = 0.0~0.30, a range of fs = 0.7 to 0.8 Since no reduction was performed, the interfacial reduction speed at fs = 0.3 to 0.7 increased, and the degree of carbon segregation was high because the overpressure was reduced in this range. From the results of Comparative Examples 5 and 6, fs = 0.
It can be seen that improvement of center segregation cannot be obtained unless proper continuous reduction is performed in the entire range of 0 to 0.8.
【0070】以上の結果から、本発明の連続鋳造方法
は、従来の方法に比較して中心偏析の低減に威力を発揮
することが明らである。
From the above results, it is clear that the continuous casting method of the present invention is more effective in reducing center segregation than the conventional method.
【0071】[0071]
【表4】 [Table 4]
【0072】[0072]
【発明の効果】本発明方法によれば、鋳造条件に関係な
く、鋳片の凝固の進展状況のみを応じて圧下制御を行え
ばよい。しかも、それによって圧下不足も過圧下もない
理想的な圧下を行うことができ、鋳片の中心偏析の軽減
に大きな効果が得られる。
According to the method of the present invention, regardless of the casting conditions, the reduction control may be performed only in accordance with the progress of solidification of the slab. In addition, this makes it possible to perform ideal rolling with no rolling reduction or excessive rolling reduction, and a great effect is obtained in reducing the center segregation of the slab.
【図面の簡単な説明】[Brief description of the drawings]
【図1】本発明方法を実施する連鋳機の概略構造図であ
る。
FIG. 1 is a schematic structural view of a continuous caster for implementing a method of the present invention.
【図2】各種のパラメータの定義を説明する鋳片断面の
模式図である。
FIG. 2 is a schematic view of a section of a slab for explaining definitions of various parameters.
【図3】固液界面の総圧下量ΣδI と炭素偏析度との関
係の一例を示す図である。
FIG. 3 is a diagram showing an example of the relationship between the total reduction amount Δδ I at the solid-liquid interface and the degree of carbon segregation.
【図4】固液界面圧下速度RI と炭素偏析度との関係の
一例を示す図である。
FIG. 4 is a diagram showing an example of the relationship between the solid-liquid interfacial reduction velocity R I and the degree of carbon segregation.
【図5】表面圧下速度RS と炭素偏析度との関係の一例
を示す図である。
FIG. 5 is a diagram showing an example of the relationship between the surface rolling velocity R S and the degree of carbon segregation.
【図6】圧下パターンと中心偏析との関係の一例を示す
図である。
FIG. 6 is a diagram illustrating an example of a relationship between a rolling pattern and center segregation.
【図7】圧下効率の鋳造方向推移の一例を示す図であ
る。
FIG. 7 is a diagram showing an example of transition of the rolling efficiency in the casting direction.
【図8】界面圧下速度RI の鋳造方向推移の一例を示す
図である。
FIG. 8 is a diagram showing an example of transition of the interfacial reduction speed R I in the casting direction.
【符号の説明】[Explanation of symbols]
1:水冷銅鋳型、2:浸漬ノズル、3:溶鋼、4:凝固
シェル、5:固液界面 6:サポートロール群、7:圧下ロ ル群、8:ピンチ
ロール、9:非圧下部 10:圧下部
1: water-cooled copper mold, 2: immersion nozzle, 3: molten steel, 4: solidified shell, 5: solid-liquid interface 6: support roll group, 7: rolling roll group, 8: pinch roll, 9: non-pressed lower part 10: Depression
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平8−132205(JP,A) 特開 平8−132203(JP,A) 特開 平7−299550(JP,A) 特開 平6−262324(JP,A) 特開 平4−309446(JP,A) 特開 平4−279265(JP,A) 特開 平4−22549(JP,A) 特開 昭63−63561(JP,A) 特開 昭62−158554(JP,A) (58)調査した分野(Int.Cl.6,DB名) B22D 11/20 B22D 11/128 350 B22D 27/09 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-132205 (JP, A) JP-A 8-132203 (JP, A) JP-A-7-299550 (JP, A) JP-A-6-132 262324 (JP, A) JP-A-4-309446 (JP, A) JP-A-4-279265 (JP, A) JP-A-4-22549 (JP, A) JP-A-63-63561 (JP, A) JP-A-62-158554 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) B22D 11/20 B22D 11/128 350 B22D 27/09

Claims (2)

    (57)【特許請求の範囲】(57) [Claims]
  1. 【請求項1】連続鋳造鋳片の末期凝固部で軽圧下を加え
    る連続鋳造方法において、圧下開始点を 0.0≦fs≦0.2
    の範囲とし、圧下終了点を 0.8≦fs≦1.0 とし、その間
    において連続圧下を行い、かつ、流動限界固相率を基準
    とした固液界面における圧下量の総和を 0.6〜1.4mm 以
    下とすることを特徴とする連続鋳造方法。ただし、fsは
    鋳片の厚み中心固相率である。
    In a continuous casting method in which a light reduction is performed in a late solidification part of a continuous casting slab, a rolling start point is set to 0.0 ≦ fs ≦ 0.2.
    The rolling end point shall be 0.8 ≤ fs ≤ 1.0, during which continuous rolling is performed, and the total amount of rolling at the solid-liquid interface based on the flow limit solid fraction shall be 0.6 to 1.4 mm or less. A continuous casting method characterized by the following. Here, fs is the thickness center solid fraction of the slab.
  2. 【請求項2】連続鋳造鋳片の末期凝固部で軽圧下を加え
    る連続鋳造方法において、圧下開始点を 0.0≦fs≦0.2
    の範囲とし、圧下終了点を 0.8≦fs≦1.0 とし、その間
    において連続圧下を行い、かつ、流動限界固相率を基準
    とした固液界面における圧下速度を0.15〜0.30mm/min以
    下とすることを特徴とする連続鋳造方法。ただし、fsは
    鋳片の厚み中心固相率である。
    2. A continuous casting method in which a light reduction is applied in a final solidification portion of a continuous cast slab, wherein a rolling start point is set to 0.0 ≦ fs ≦ 0.2.
    The rolling end point is set to 0.8 ≦ fs ≦ 1.0, during which continuous rolling is performed, and the rolling speed at the solid-liquid interface based on the flow limit solid fraction is set to 0.15 to 0.30 mm / min or less. A continuous casting method characterized by the following. Here, fs is the thickness center solid fraction of the slab.
JP27640894A 1994-11-10 1994-11-10 Continuous casting method Expired - Lifetime JP2964888B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP27640894A JP2964888B2 (en) 1994-11-10 1994-11-10 Continuous casting method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP27640894A JP2964888B2 (en) 1994-11-10 1994-11-10 Continuous casting method

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Publication Number Publication Date
JPH08132204A JPH08132204A (en) 1996-05-28
JP2964888B2 true JP2964888B2 (en) 1999-10-18

Family

ID=17568995

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Application Number Title Priority Date Filing Date
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Country Link
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008207201A (en) * 2007-02-26 2008-09-11 Jfe Steel Kk Method for manufacturing continuously cast slab
JP5413289B2 (en) * 2010-04-16 2014-02-12 Jfeスチール株式会社 Center segregation judgment method for continuous cast slabs
CN107377919A (en) * 2017-07-20 2017-11-24 东北大学 A kind of method for improving bearing steel strand central dense degree

Also Published As

Publication number Publication date
JPH08132204A (en) 1996-05-28

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