JPS5835784B2 - Continuous casting method for steel slabs - Google Patents

Continuous casting method for steel slabs

Info

Publication number
JPS5835784B2
JPS5835784B2 JP6576879A JP6576879A JPS5835784B2 JP S5835784 B2 JPS5835784 B2 JP S5835784B2 JP 6576879 A JP6576879 A JP 6576879A JP 6576879 A JP6576879 A JP 6576879A JP S5835784 B2 JPS5835784 B2 JP S5835784B2
Authority
JP
Japan
Prior art keywords
mold
flow
electromagnetic flow
nozzle
electromagnetic
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
Application number
JP6576879A
Other languages
Japanese (ja)
Other versions
JPS55158860A (en
Inventor
徹郎 大橋
仁 丹野
栄一 竹内
博務 藤井
一茂 木村
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 JP6576879A priority Critical patent/JPS5835784B2/en
Publication of JPS55158860A publication Critical patent/JPS55158860A/en
Publication of JPS5835784B2 publication Critical patent/JPS5835784B2/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10Supplying or treating molten metal
    • B22D11/11Treating the molten metal
    • B22D11/114Treating the molten metal by using agitating or vibrating means
    • B22D11/115Treating the molten metal by using agitating or vibrating means by using magnetic fields

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)

Description

【発明の詳細な説明】 本発明は鋼スラブの連続鋳造方法に関し、特に鋳型内の
凝固界面に接続した電磁流動を効果的に形成して連続鋳
造する方法に関する。
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuous casting of steel slabs, and more particularly to a method for continuous casting by effectively forming an electromagnetic flow connected to a solidification interface in a mold.

リムド鋼、セミキルド鋼相当の鋼を連続鋳造で製造する
試みは古くから行なわれているが、操業性並びに品質、
特に鋳片表面に発生する気泡欠陥の問題から未だ実用化
に至っていない。
Attempts to manufacture steel equivalent to rimmed steel or semi-killed steel by continuous casting have been made for a long time, but there have been problems with operability, quality,
In particular, it has not yet been put into practical use due to the problem of bubble defects that occur on the surface of the slab.

溶鋼中に発生するガス気泡を除去する方法については、
例えば電磁攪拌力を利用するものが検討されている。
For information on how to remove gas bubbles generated in molten steel,
For example, methods using electromagnetic stirring force are being considered.

この電磁攪拌力を利用して溶鋼中のガス気泡を除去する
方法については多数の報告があるが、これら公知の方法
は倒れもすでに生じてしまったガス気泡を除去する方法
であり、強烈な力を必要とする。
There are many reports on methods of removing gas bubbles in molten steel using this electromagnetic stirring force, but these known methods are methods for removing gas bubbles that have already formed and require intense force. Requires.

これは発生してしまった後のガス気泡を物理的に除去す
るからであり、このようにガス気泡を物理的に除去する
場合には鋳型内湯面を大きく乱してしまい、いわゆるパ
ウダーキャスティングのメリットを消失させてしまう結
果となる。
This is because gas bubbles are physically removed after they have been generated, and when gas bubbles are physically removed in this way, the mold surface is greatly disturbed, which is an advantage of so-called powder casting. This results in the disappearance of the .

そこで本出願人は先にガス気泡に成長する前のガス気泡
の核の段階で流動を与える方法すなわちガス気泡となっ
てしまった段階よりも、それに成長する前の核の段階の
方がはるかに小さい力で除去できること、並びにこのガ
ス気泡の核は鋳型内湯面からすでに発生することに着目
し、この湯面自身に溶鋼流動を与えれば湯面を大きく乱
すことのない極めてゆるやかな流速で鋳片表面でのガス
気泡の発生が抑止できることを提案した(特昭願53−
99972号)。
Therefore, the applicant proposed a method of providing flow at the stage of the nucleus of a gas bubble before it grows into a gas bubble. Focusing on the fact that it can be removed with a small force and that the core of these gas bubbles is already generated from the surface of the molten metal in the mold, by applying molten steel flow to the molten metal surface itself, the slab can be removed at an extremely slow flow rate that does not significantly disturb the surface of the molten metal. proposed that the generation of gas bubbles on the surface could be suppressed (Special Application No. 53-
No. 99972).

しかしながら、この方法では、湯面への流動の与え方と
して湯面に対して垂直の回転流を採用した場合、流速が
湯面を乱さないようなゆるやかなものであることから、
鋳型の両短辺側湯面部において溶鋼流動のないよどみ部
の生じるのは避けられず、酸素含有量によっては鋳片表
面にガス気泡が露呈する欠点があった。
However, in this method, when a rotating flow perpendicular to the molten metal surface is adopted as a method of imparting flow to the molten metal surface, the flow velocity is slow enough not to disturb the molten metal surface.
It is unavoidable that stagnation areas where the molten steel does not flow occur at the hot water surface on both short sides of the mold, and depending on the oxygen content, gas bubbles may be exposed on the surface of the slab.

しかして、上記欠点を解消すべく種々検討したところ、
鋳型内の凝固界面に連続した電磁流動を与えるようにす
れば上記欠点が解消できることが判明した。
However, after conducting various studies to resolve the above drawbacks, we found that
It has been found that the above drawbacks can be overcome by applying continuous electromagnetic flow to the solidification interface within the mold.

すなわち、このような電磁流動であると上記のような溶
鋼流動のよどみ部の発生は無くなり鋳片表面でのガス気
泡の発生は確実に抑止できるものである。
That is, with such electromagnetic flow, the above-mentioned stagnant portions of the molten steel flow will not occur, and the generation of gas bubbles on the surface of the slab can be reliably suppressed.

本発明でいう電磁流動とは以下のものを指す。The electromagnetic flow referred to in the present invention refers to the following.

前述の先願と同様、 1)気泡の核発生はその成長に比べておこりにくく所定
以上の元素濃度を必要とする。
Similar to the previous application mentioned above, 1) Nucleation of bubbles is less likely to occur than bubble growth and requires an element concentration above a predetermined value.

2)気泡の核は凝固開始点すなわち湯面部位の凝固界面
からすでに発生する。
2) Bubbles nuclei are already generated from the solidification start point, that is, the solidification interface at the hot water level.

3)元素濃度は凝固界面において著しく濃化する。3) Element concentration is significantly concentrated at the solidification interface.

事実に着目し、鋳型内溶鋼湯面部位凝固界面における元
素濃度を気泡の核の発生限界以下とし、しかもその際に
湯面上のパウダーを乱さない程度の流速の電磁流動を指
す。
Focusing on the facts, it refers to electromagnetic flow that keeps the element concentration at the solidification interface of the molten steel surface in the mold below the limit for bubble nucleation, and at a flow rate that does not disturb the powder on the surface.

すなわち、鋳型内湯面部位の凝固界面全周囲に与えられ
る気泡の核の生成の抑制に有効な膜状の溶鋼流動をいい
、後に詳述する如く特に鋳型に設置したりニヤモーター
にて与える電磁流動をいう。
In other words, it refers to a film-like flow of molten steel that is applied all around the solidification interface at the surface of the mold and is effective in suppressing the formation of bubble nuclei, and as will be explained in detail later, it is particularly an electromagnetic flow that is installed in the mold or applied by a near motor. means.

このように鋳造過程において湯面部位の凝固界面周壁に
溶鋼の電磁流動を与えることにより凝固界面での成分元
素の濃化が抑制されて得られる鋳片の表層部全周に健全
な凝固層が形成されしかもこの流動は後述の如くゆるや
かで、かつ凝固壁に近い部分に与えるものであることか
ら湯面()9夕→を何ら乱すことがないものである。
In this way, by applying electromagnetic flow of molten steel to the surrounding wall of the solidification interface at the surface area during the casting process, the concentration of component elements at the solidification interface is suppressed, and a healthy solidified layer is formed around the entire surface layer of the resulting slab. This flow is gradual as will be described later, and since it is applied to a portion close to the solidification wall, it does not disturb the surface of the molten metal in any way.

上記電磁流動は、後述の如く気泡核の生成抑制に必要で
かつ湯面上パウダーを乱さない0.1〜1.0弓凍℃の
流速である。
The electromagnetic flow has a flow rate of 0.1 to 1.0° C., which is necessary for suppressing the generation of bubble nuclei and does not disturb the powder on the surface of the hot water, as will be described later.

而して、この電磁流動の及ぶ範囲が広い場合には、溶鋼
注入用浸漬ノズルに影響を受けて湯面パウダーに乱れが
生じ、パウダー巻き込み等により正常なパウダーキャス
ティングが実施できなくなるので、電磁流動はできる限
り凝固壁に近い部分で生じさせるのが良い。
If the area covered by this electromagnetic flow is wide, the molten metal surface powder will be disturbed due to the influence of the immersion nozzle for pouring molten steel, and normal powder casting will not be possible due to powder entrainment. should be generated as close to the solidified wall as possible.

このためには電磁流動を与えるリニヤモーターの周波数
を例えば5〜20 Hzのうちでも高い側に設定し、得
られる流速勾配を大きくし凝固壁側で高く、離れる(鋳
型中央へ行く)に従って急速に低くなるようにする必要
がある。
To achieve this, the frequency of the linear motor that provides electromagnetic flow is set to a higher value, for example, between 5 and 20 Hz, and the resulting flow velocity gradient is increased so that it is high on the solidified wall side and rapidly increases as it moves away from the wall (toward the center of the mold). It needs to be lower.

ところが周波数を高く設定すると推力が小さくなってリ
ニヤモーターの影響範囲がせまくなり、鋳型高さ方向で
の設置個数を増加する必要が生じたり、あるいは流速の
絶対値そのものも低下するので、電流値を向上させるこ
とによりこれらを解消する。
However, if the frequency is set high, the thrust force will be small and the range of influence of the linear motor will be narrowed, making it necessary to increase the number of molds installed in the height direction of the mold, or the absolute value of the flow velocity itself will decrease. These can be resolved by improving the performance.

なお鋳型中央にまで溶鋼流動を与える公知例のものは本
発明でいう電磁流動とは逆に流速勾配を成るべく小さく
するため周波数を成るべく低く設定しているわけである
が、これであるといくら速度勾配が小さいといっても壁
面側の流速は早くなり、結果としてパウダーを乱すよう
な流速となってしまう。
Incidentally, in the known examples that cause the molten steel to flow to the center of the mold, the frequency is set as low as possible in order to minimize the flow velocity gradient, contrary to the electromagnetic flow referred to in the present invention. No matter how small the velocity gradient is, the flow velocity on the wall side becomes faster, resulting in a flow velocity that disturbs the powder.

上記電磁流動の厚み、すなわち0.1〜1.0r11/
Secといった気泡の核の抑制に有効な流速を有する流
動厚み(有効厚み)については、前述の如く成るべく(
凝固壁面近くで)薄い方が好ましく、リニヤモーターの
周波数あるいは電流条件を適正に選定して流速勾配を大
きくすることによりこれを実現するわけであるが、この
際凝固壁面において例えば最大1.0m/AeCの流速
を得る場合第1図に示すように凝固壁面から約10〜2
o%の範囲において上記有効厚みが形成される。
The thickness of the electromagnetic flow, i.e. 0.1 to 1.0r11/
Regarding the flow thickness (effective thickness) having a flow velocity effective for suppressing bubble nuclei such as Sec, as described above, (
It is preferable that the thickness be thinner (near the solidified wall surface), and this is achieved by appropriately selecting the frequency or current conditions of the linear motor to increase the flow velocity gradient. When obtaining the flow rate of AeC, as shown in Figure 1, the flow rate is approximately 10 to 2
The above effective thickness is formed in the range of 0%.

つまり、この発明で対象とする電磁流動の有効厚みは1
0〜20鬼以下を指すものである。
In other words, the effective thickness of the electromagnetic flow targeted by this invention is 1
This refers to 0 to 20 demons or less.

ちなみに、上記第1図に示した最大値側の例において1
0〜20鬼以上凝固壁面から離れたところでの流速は極
めて低くなり湯面状況に殆んど影響を与えていない。
By the way, in the example on the maximum value side shown in Figure 1 above, 1
The flow velocity at a distance of 0 to 20 degrees or more from the solidified wall surface is extremely low and has almost no effect on the hot water level.

つまりマクロ的には10〜20%の厚みの電磁流動が膜
状で生じているとみなされる。
In other words, from a macroscopic perspective, electromagnetic flow with a thickness of 10 to 20% is considered to occur in the form of a film.

以上のように、リムド、セミキルド鋼等のいわゆる未脱
酸鋼の連鋳化に際しては、鋳型内凝固界面における連続
した膜状の電磁流動が有効であるが、一方、キルド鋼に
おいてもこのような電磁流動が有効である。
As mentioned above, when continuously casting so-called undeoxidized steels such as rimmed and semi-killed steels, a continuous film-like electromagnetic flow at the solidification interface in the mold is effective. Electromagnetic flow is effective.

すなわち、キルド鋼を連続鋳造により製造する場合、ア
ルミの割れ感受性により表面疵が発生し易く、このため
鋳型内パウダーを低粘性のものにして、パウダーの不均
一流入を防止したり、スラグ化率を改善して対処してい
るが、これらによっても抜本的に鋳片表面欠陥の発生は
防止されていない。
In other words, when killed steel is manufactured by continuous casting, surface flaws are likely to occur due to the sensitivity of aluminum to cracking. Therefore, the powder in the mold should be made with a low viscosity material to prevent uneven inflow of powder and to reduce the slagging rate. However, these efforts have not fundamentally prevented the occurrence of surface defects on slabs.

このようなキルド鋼の連続鋳造に当って、上記のような
電磁流動を与えると、凝固界面に与えられる溶鋼流動に
てここに元素濃度の低くなった擬似リム層が極めてゆる
やかな流速でもって形成され、これによって鋳片表面の
アルミの割れ感受性が低くなり、表面欠陥の発生が抑制
できるものである。
When such electromagnetic flow is applied during continuous casting of killed steel, a pseudo rim layer with a low element concentration is formed at an extremely slow flow rate by the molten steel flow applied to the solidification interface. This reduces the cracking susceptibility of the aluminum on the surface of the slab and suppresses the occurrence of surface defects.

このように、脱酸鋼、未脱酸鋼にかかわらず、鋼の連鋳
にとっては鋳型内凝固界面における連続した電磁流動が
極めて有効である。
In this way, continuous electromagnetic flow at the solidification interface in the mold is extremely effective for continuous casting of steel, regardless of whether it is deoxidized steel or non-deoxidized steel.

しかしながら、上記の電磁流動を与える場合、ノズル外
径とスラブ鋳型両長辺との距離が上記電磁流動の有効厚
みより狭いと溶鋼注入浸漬ノズルが上記流動の障害とな
り、スムースな流動が得られず、結果として湯面並びに
湯面上パウダーを乱し、正常なパウダーキャスティング
が期待できない。
However, when applying the above electromagnetic flow, if the distance between the nozzle outer diameter and both long sides of the slab mold is narrower than the effective thickness of the above electromagnetic flow, the molten steel injection immersion nozzle becomes an obstacle to the above flow, making it impossible to obtain smooth flow. As a result, the hot water surface and the powder on the hot water surface are disturbed, and normal powder casting cannot be expected.

本発明は鋳型内凝固界面に電磁流動を与える場合に溶鋼
注入浸漬ノズルと鋳型両長辺との距離を電磁流動の有効
厚み以上とすることにより上記欠点を解消したものであ
る。
The present invention solves the above-mentioned drawbacks by making the distance between the molten steel injection immersion nozzle and both long sides of the mold equal to or greater than the effective thickness of the electromagnetic flow when applying electromagnetic flow to the solidification interface in the mold.

即ち本発明は鋼スラブ鋳型の両長辺に沿って設置したリ
ニヤモーターにて両長辺と接する鋳型内溶鋼に長辺長さ
方向で互に異なる方向に推力を与えることにより鋳型内
溶鋼凝固界面に連続した電磁流動を形成して連続鋳造す
るに当り、スラブ鋳型の両長辺と溶鋼注入浸漬ノズルと
の距離を上記凝固界面に生じさせた電磁流動の有効厚み
以上とすることを特徴とする鋼スラブの連続鋳造方法で
ある。
That is, the present invention applies thrust forces in different directions along the length of the long sides to the molten steel in the mold that is in contact with both long sides using linear motors installed along both long sides of a steel slab mold, thereby improving the solidification interface of the molten steel in the mold. In performing continuous casting by forming a continuous electromagnetic flow, the distance between both long sides of the slab mold and the molten steel injection immersion nozzle is set to be equal to or greater than the effective thickness of the electromagnetic flow generated at the solidification interface. This is a continuous casting method for steel slabs.

以下に本発明を詳述する。第2図は本発明を実施する一
例装置を示す。
The present invention will be explained in detail below. FIG. 2 shows an exemplary apparatus for implementing the present invention.

第2図に示すように本発明においては、スラブ鋳型1の
両長辺2に沿ってそれぞれ電磁流動を付与するためのり
ニヤモーター3を設置する。
As shown in FIG. 2, in the present invention, glue motors 3 are installed along both long sides 2 of the slab mold 1 to apply electromagnetic flow.

この推力を互いに異なる方向4,4′に与えるようにし
て凝固界面に連続した電磁流動5を与える。
By applying this thrust in mutually different directions 4 and 4', a continuous electromagnetic flow 5 is applied to the solidification interface.

この際本発明においては、鋳型長辺2と溶鋼注入浸漬ノ
ズル6との間隔7を前述の電磁流動の有効厚み以上定量
的には10〜20鬼以上確保するものである。
At this time, in the present invention, the distance 7 between the long side 2 of the mold and the molten steel injection immersion nozzle 6 is quantitatively ensured by 10 to 20 degrees or more than the effective thickness of the electromagnetic flow described above.

すなわち、近年においては生産性の向上から鋳型短辺長
さ、すなわち鋳片厚み一杯の径を有するノズルを採用し
ているが、これではノズル6と長辺2とで形成される上
記電磁流動の流路が狭く、有効厚み以下となってしまう
That is, in recent years, in order to improve productivity, a nozzle having a diameter equal to the length of the short side of the mold, that is, the thickness of the slab, has been adopted, but with this, the electromagnetic flow formed by the nozzle 6 and the long side 2 is The flow path is narrow and the thickness is less than the effective thickness.

このように電磁流動の流路がその有効厚みより狭い場合
には、ノズル6が電磁流動5の障害となり、電磁流動5
の円滑さが損なわれて電磁流動5のノズル6への衝突に
て湯面上パウダーを乱してしまう。
In this way, when the electromagnetic flow path is narrower than its effective thickness, the nozzle 6 becomes an obstacle to the electromagnetic flow 5, and the electromagnetic flow 5
The smoothness of the melt is impaired, and the powder on the surface of the hot water is disturbed by the collision of the electromagnetic fluid 5 with the nozzle 6.

パウダーに乱れが生じると、パウダーの巻き込み等のト
ラブルにつながり、正常なパウダーキャスティングが期
待できない。
If the powder is disturbed, problems such as powder entrainment may occur, and normal powder casting cannot be expected.

このような欠点は長辺に比し短辺が著しく短かいスラブ
鋳型特有の欠点といえ、フントム、ビレット鋳型ではあ
まり考えられなかった欠点である。
This drawback can be said to be unique to slab molds, in which the short sides are significantly shorter than the long sides, and is a drawback that has not been considered much with Funtom and billet molds.

本発明者等の実験によると、上記ノズル6と長辺との距
離7は、溶鋼温度、組成等により変化するが、後述する
0、1〜1.0 m/secの流速を有する電磁流動の
有効厚み以上とすれば上記欠点は解消され、これにより
、上記流速範囲の電磁流動の円滑さが保証されることす
なわち、ノズルが電磁流動の障害とならないことが判明
した。
According to experiments conducted by the present inventors, the distance 7 between the nozzle 6 and the long side varies depending on the molten steel temperature, composition, etc. It has been found that if the thickness is equal to or greater than the effective thickness, the above-mentioned drawbacks are eliminated, and thereby smooth electromagnetic flow is guaranteed in the above-mentioned flow velocity range, that is, the nozzle does not become an obstacle to electromagnetic flow.

ところが一方、ノズルを小さくしすぎる(距離7を大き
くする)と、生産性を考慮した鋳造量の確保のためには
注入溶鋼のノズルからの噴出流速を早くせねばならない
On the other hand, if the nozzle is made too small (distance 7 is made large), the flow velocity of the injected molten steel from the nozzle must be increased in order to secure a casting amount that takes into account productivity.

しかしこのノズルからの噴出流速が早くなりすぎると、
その噴出方向が例え長辺方向といえども上記凝固界面に
与える流速が0.1〜1.0m/secとゆるやかであ
ることから、このノズル噴出流が直接あるいは鋳型壁に
衝突して上昇流となって間接的にこれに悪影響を与え、
電磁流動の円滑さを害する。
However, if the jet flow velocity from this nozzle becomes too fast,
Even if the ejecting direction is in the long side direction, the flow velocity applied to the solidification interface is slow at 0.1 to 1.0 m/sec, so the nozzle ejected flow directly or collides with the mold wall, resulting in an upward flow. indirectly affecting this,
It harms the smoothness of electromagnetic flow.

これでは、上述の通路のせまいことと同様の問題点を呈
する結果となりもとのもくあみとなってしまう。
This results in the same problem as the narrow passage mentioned above, resulting in the original difficulty.

この点については、ノズルの孔口(溶鋼の噴出孔)を大
きくすることにより対処可能である。
This point can be addressed by enlarging the nozzle opening (molten steel spouting hole).

そして生産量上の問題から長辺とノズルの間隔を有効厚
み以上にできない場合には、ノズルとしてへん平ノズル
を使用すれば間隔確保が可能となりこの問題は解消でき
る。
If the distance between the long side and the nozzle cannot be made greater than the effective thickness due to production issues, using a flat nozzle as the nozzle will make it possible to secure the distance and solve this problem.

なお上記長辺とノズルの間隔について、定量的には有効
厚みがおおむね10〜20鬼の範囲であることから10
〜20鬼以上である。
Regarding the distance between the long side and the nozzle, quantitatively, the effective thickness is approximately 10 to 20 mm.
~20 demons or more.

上限については鋳型の大きさ、ノズル径等から常識的に
決定される。
The upper limit is determined by common sense from the mold size, nozzle diameter, etc.

このように本発明においてはスラブ鋳型内における電磁
流動の形成に当っては、スラブ鋳型の長辺とノズルとの
距離が極めて重要であることに着目して上記スラブ鋳型
の長辺とノズルとの距離を電磁流動の有効厚み以上定量
的には10〜20鬼以上として鋳型向凝固界面に電磁流
動を与えるようにしたもので、これにより安定的に湯面
上パウダーを乱すことのない電磁流動を得るようにした
ものである。
In this way, the present invention focuses on the fact that the distance between the long side of the slab mold and the nozzle is extremely important in forming electromagnetic flow within the slab mold, and the distance between the long side of the slab mold and the nozzle is determined. The distance is quantitatively set at 10 to 20 degrees or more, which is greater than the effective thickness of electromagnetic fluid, so that electromagnetic fluid is applied to the pro-solidification interface of the mold, thereby stably producing electromagnetic fluid that does not disturb the powder on the surface of the molten metal. This is what I did to get it.

第3図は本発明の一装置例の模型図を示し、第2図のA
−A断面を示す。
FIG. 3 shows a model diagram of an example of the device of the present invention, and A in FIG.
-A cross section is shown.

第3図に示すように本発明では、鋳型1の長辺2とノズ
ル6との間隔7を電磁流動の有効厚み以上、例えば20
%として鋳型外方に設けたりニヤモーター3にて電磁流
動5を与える。
As shown in FIG. 3, in the present invention, the distance 7 between the long side 2 of the mold 1 and the nozzle 6 is greater than the effective thickness of electromagnetic flow, for example, 20 mm.
%, it is provided outside the mold or a near motor 3 is used to apply an electromagnetic flow 5.

この第3図の例ではりニヤモーター3は湯面8とノズル
6の噴出位置9との間に設置しこれにより湯面8を含み
、ここから所定凝固厚が得られるまでの部位の凝固界面
に連続した膜状の電磁流動を与えるようにしている。
In the example shown in FIG. 3, the girder motor 3 is installed between the hot water surface 8 and the ejection position 9 of the nozzle 6, thereby including the hot water surface 8 and the solidification interface in the area from where a predetermined solidification thickness is obtained. A continuous film-like electromagnetic flow is applied to the

電磁流動を与える例としては第3図に示した例以外に第
4図aあるいは第4図すに示すようなものでも良い。
As an example of applying electromagnetic flow, in addition to the example shown in FIG. 3, an example shown in FIG. 4a or FIG. 4s may be used.

第4図aの例は湯面8位置に設置したりニヤモーター3
にて湯面8を含みそこから所定凝固厚が得られる位置ま
で膜状の電磁流動5の影響が及ぶようにしたもので、第
4図すの例は湯面8からノズル噴出位置9まで及ぶリニ
ヤモーター3を設置したものである。
The example in Fig. 4a is the one installed at the 8th position of the hot water level and the near motor 3.
The influence of the film-like electromagnetic flow 5 extends from the hot water level 8 to a position where a predetermined solidification thickness is obtained. It is equipped with 3 linear motors.

而して上記のスラブ鋳型内の凝固界面に与える電磁流動
の流速についてはQ、1〜1.0m/sec好ましくは
0.4〜1.0m/secといったゆるやかなものが好
ましい。
The flow velocity of the electromagnetic fluid applied to the solidification interface in the slab mold is preferably slow, Q, 1 to 1.0 m/sec, preferably 0.4 to 1.0 m/sec.

すなわち、0.1〜0.4 m / sec以−ヒの流
速であれば気泡様の生成の抑制並びに擬似リム層の形成
に有効であり、一方1.0m/sec以上では効果が頭
打ちとなるばかりか、電磁流動の形成の際の長辺からの
流れが強くなり過ぎ湯面を乱してパウダーキャスティン
グ本来のメリットを消失させてしまうといった新たな他
の問題をおこすからである。
That is, a flow rate of 0.1 to 0.4 m/sec or higher is effective in suppressing the generation of bubbles and forming a pseudo rim layer, while at a flow rate of 1.0 m/sec or higher, the effect reaches a plateau. Moreover, when electromagnetic flow is formed, the flow from the long sides becomes too strong, which disturbs the surface of the melt and causes other problems, such as eliminating the original merits of powder casting.

なお本発明においては、湯面にも上記膜状の電磁流動を
与えるとしたが、これは前述の如く、特に未脱酸鋼の場
合にガス気泡の核が湯面からすでに発生するからであり
、ここから所定厚の健全凝固層が得られるまでこの凝固
界面に流動を与えて畳畳ガス気泡がこの凝固層内で発生
するのを完全に防止するためである。
In the present invention, the above-mentioned film-like electromagnetic flow is applied to the hot water surface, but this is because, as mentioned above, especially in the case of unoxidized steel, the nuclei of gas bubbles are already generated from the hot water surface. This is to completely prevent generation of gas bubbles in the solidified layer by applying flow to this solidified interface until a sound solidified layer of a predetermined thickness is obtained.

この健全凝固層を所定厚み分完全に形成するという点で
は脱酸鋼も共通しており、脱酸鋼の場合も同様湯面から
この流動を与える。
Deoxidized steel is also common in that this healthy solidified layer is completely formed to a predetermined thickness, and in the case of deoxidized steel, this flow is also applied from the surface of the molten metal.

そして更に本発明に従う電磁流動を与える場合本発明で
はりニヤモーターにより特に鋳型壁面に近い位置すなわ
ち凝固界面にそれを与えるので、溶鋼の流れはこの部位
に強く鋳型中央部においては極めて小さいものであるこ
とから、本発明に従う距離を確保することによりノズル
の存在による湯面の乱れは無く従ってこの電磁流動はパ
ウダーキャスティングに何ら悪影響を与えるものではな
い。
Furthermore, when applying electromagnetic flow according to the present invention, in the present invention, the magnetic flow is applied particularly to a position close to the mold wall surface, that is, at the solidification interface, using a linear motor, so that the flow of molten steel is strong in this area and is extremely small in the center of the mold. Therefore, by ensuring the distance according to the present invention, there is no disturbance of the hot water level due to the presence of the nozzle, and therefore, this electromagnetic flow does not have any adverse effect on powder casting.

以上のように本発明は鋳型の長辺とノズルとの距離を電
磁流動の有効厚さ以上としてスラブ鋳型内の凝固界面に
膜状の電磁流動を与えるようにし、これにより安定的に
湯面パウダーを乱すことのない流動を得るようにしたも
のである。
As described above, in the present invention, the distance between the long side of the mold and the nozzle is set to be equal to or greater than the effective thickness of electromagnetic flow, so that a film-like electromagnetic flow is applied to the solidification interface in the slab mold, thereby stably powdering the surface of the molten metal. This is to obtain a flow that does not disturb the flow.

次に本発明の実施例を比較例と共に説明する。Next, examples of the present invention will be described together with comparative examples.

下記表に示す未脱酸鋼(AI、2)、脱酸鋼(A3 、
4 )を対象に本発明を実施した。
Undeoxidized steel (AI, 2), deoxidized steel (A3,
4) The present invention was implemented for the following cases.

鋳造条件は以下の通りである。The casting conditions are as follows.

処理量は倒れも100 tonである。The throughput is 100 tons.

鋳型寸法・・・250鬼(厚)X2100%(巾)鋳造
速度・・’ Q、 7 [71/ mt nリニヤモー
ター設置位置・・・鋳型内湯面下100並びに推力方向
、設置 鬼で各長辺に1ケ、位置の鋳片凝固厚
それぞれの推力方向が反対となるよう設 置 凝固厚3鬼 リニヤモーターの出力 ・・・ 鋳型内湯面から凝固厚
さ5Xの範囲の凝 固界面において壁面 の流速が0.8 m/sec となる様調整 電磁流動の有効膜厚 ・・・ 15鬼 鋳型長辺とノズルとの距離・・・各20%注入ノズル噴
出方向、・・・両短辺方向、湯面下噴出口位置
25鬼 以上の実施例1〜4伺れの場合も鋳型内湯面パウダーの
乱れは一切なく、実施例1,2においては鋳片表面にガ
ス気泡の無い層が周囲全体に約5鬼形成され、その内部
にガス気泡が位置していた。
Mold dimensions: 250 mm (thickness) 1 piece, solidified slab thickness at position
Installed so that each thrust direction is opposite Output of linear motor with solidification thickness of 3 mm...Adjusted electromagnetic so that the flow velocity on the wall surface is 0.8 m/sec at the solidification interface in the range of 5X solidification thickness from the mold surface. Effective film thickness of flow...15 Distance between long side of mold and nozzle...20% each Injection nozzle ejection direction...Both short side directions, ejection outlet position below the surface of the molten metal
Even in the cases of Examples 1 to 4, where the mold thickness was 25 or more, there was no disturbance of the powder on the surface of the mold, and in Examples 1 and 2, a layer without gas bubbles was formed around the entire periphery of the slab surface. Gas bubbles were located inside it.

そして実施例3,4においては鋳片表面に擬似リム層が
周囲全体に均一に約5鬼形成されていた。
In Examples 3 and 4, about five pseudo rim layers were uniformly formed around the entire circumference on the surface of the slab.

以上の如くして得た鋳片を常法に従い最終成品にしたが
、実施例1,2においてはガス気泡に基づく表面欠陥は
全く見られなかったし、3,4においては表面手入れ率
は50%減少した。
The slabs obtained as described above were made into final products according to a conventional method. In Examples 1 and 2, no surface defects due to gas bubbles were observed, and in Examples 3 and 4, the surface care rate was 50. %Diminished.

このように実施例ではスラブ鋳型内の凝固界面にパウダ
ーを乱すことのない電磁流動が得られる。
In this way, the embodiment provides electromagnetic flow that does not disturb the powder at the solidification interface within the slab mold.

比較例 実施例1〜4と同一組成の溶鋼を注入ノズルの太さを変
更し、長辺との距離を10鬼として鋳造した。
Comparative Example Molten steel having the same composition as Examples 1 to 4 was cast by changing the thickness of the injection nozzle and setting the distance from the long side to 10 mm.

ところが鋳造生湯面上パウダーの乱れが激しくなり正常
なパウダーキャスティングが行なえず、パウダー巻き込
みによるブレークアウトトラブルかけ念されたので、す
ぐ電磁流動の付与を中止した。
However, the turbulence of the powder on the surface of the casting hot water became so severe that normal powder casting could not be performed, and we feared a breakout problem due to powder entrainment, so we immediately stopped applying electromagnetic fluid.

屑1,2においてはガス気泡が多発し、大きな歩留低下
となりまた3、4においては表面手入れ率は元の通常レ
ベルに戻ってしまった。
In scraps 1 and 2, gas bubbles occurred frequently, resulting in a significant decrease in yield, and in scraps 3 and 4, the surface care rate returned to the original normal level.

このように比較例においては、ノズルと長辺との距離が
狭かったためノズルが電磁流動の障害となって湯面上パ
ウダーが乱れたものと認められる。
As described above, in the comparative example, the distance between the nozzle and the long side was narrow, so it is recognized that the nozzle became an obstacle to electromagnetic flow and the powder on the surface of the hot water was disturbed.

上記実施例並びに比較例で用いたパウダーは何れも以下
のものを使用した。
The following powders were used in the above Examples and Comparative Examples.

CaO/5i02 = 1.0 A1203 =10(係) Na+=3.5 に+ =2.5 F−=4 C=4.5 粘性 at 1500℃、 2.3Poise融
点 1150’C 更に本発明の実施に際し、第5図に示したものを使用す
ると一層効果的である。
CaO/5i02 = 1.0 A1203 = 10 (coupling) Na + = 3.5 + = 2.5 F - = 4 C = 4.5 Viscosity at 1500°C, 2.3 Poise Melting point 1150'C Further implementation of the present invention In this case, it is more effective to use the one shown in FIG.

この第5図の例は鋳型を模式的に示したものであるが短
片10の形状を丸めたもので、これであると、電磁流動
の案内がスムースに行なわれる。
The example shown in FIG. 5 schematically shows a mold, and the short pieces 10 are rounded in shape, so that the electromagnetic flow can be guided smoothly.

以上実施例並びに比較例から明らかなように、本発明は
特にスラブ鋳型内の凝固界面に電磁流動を与えて連続鋳
造するに当り、鋳型の長辺とノズルの距離を電磁流動の
有効厚み以上としてスラブ鋳型内凝固界面に上記電磁流
動を与えるようにしたので凝固界面全体に湯面上パウダ
ーを乱すことのない電磁流動を確実に形成して連続鋳造
できる。
As is clear from the above Examples and Comparative Examples, the present invention is particularly advantageous in continuous casting by applying electromagnetic fluid to the solidification interface in a slab mold, by setting the distance between the long side of the mold and the nozzle to be equal to or greater than the effective thickness of the electromagnetic fluid. Since the above-mentioned electromagnetic flow is applied to the solidified interface in the slab mold, continuous casting can be performed by reliably forming electromagnetic flow throughout the solidified interface without disturbing the powder on the surface of the molten metal.

従って未脱酸鋼の連鋳化が安定して可能となると共に、
脱酸鋼の連鋳に当っては表面疵の発生低減が可能となる
Therefore, continuous casting of non-deoxidized steel becomes possible in a stable manner, and
When continuously casting deoxidized steel, it is possible to reduce the occurrence of surface defects.

このように本発明は未脱酸鋼並びに脱酸鋼の連鋳に寄与
すること犬である。
In this way, the present invention contributes to the continuous casting of unoxidized steel and deoxidized steel.

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

第1図は鋳型壁面からの距離と流速分布の関係を示す図
、第2図は本発明の一例を示す上面模式図、第3図は第
1図の1人−A断面を示す図、第4図a、bは本発明の
他の例を示す第1図1−A断面を示す図、第5図は本発
明において使用する鋳型形状を模式的に示す図tある。 1・・・鋳型、2・・・長辺、3・・・電磁攪拌器、4
,4′・・・推力方向、5・・・回転流、6・・・溶鋼
注入浸漬ノズル、7・・・間隔、8・・・湯面、9・・
・ノズル噴出位置、10・・・短辺、11・・・パウダ
ー 12・・・ノズル噴出孔。
FIG. 1 is a diagram showing the relationship between the distance from the mold wall surface and the flow velocity distribution, FIG. 2 is a schematic top view showing an example of the present invention, FIG. 4a and 4b are views showing a cross section taken along line A in FIG. 1, showing another example of the present invention, and FIG. 5 is a view t schematically showing the mold shape used in the present invention. 1...Mold, 2...Long side, 3...Magnetic stirrer, 4
, 4'... Thrust direction, 5... Rotating flow, 6... Molten steel injection immersion nozzle, 7... Interval, 8... Molten metal surface, 9...
- Nozzle ejection position, 10...Short side, 11...Powder 12...Nozzle ejection hole.

Claims (1)

【特許請求の範囲】[Claims] 1 鋼スラブ鋳型の両長辺に沿って設置したりニヤモー
ターにて両長辺と接する鋳型内溶鋼に長辺長さ方向で互
いに異なる方向に推力を与えることにより鋳型内溶鋼凝
固界面に連続した電磁流動を形成して連続鋳造するに当
り、スラブ鋳型の両長辺と溶鋼注入浸漬ノズルとの距離
を上記凝固界面に生じさせた電磁流動の有効厚み以上と
することを特徴とする鋼スラブの連続鋳造方法。
1. A steel slab mold is installed along both long sides of the mold, or a near motor is used to apply thrust in different directions along the length of the long sides to the molten steel in the mold that is in contact with both long sides. In continuous casting by forming electromagnetic flow, the distance between both long sides of the slab mold and the molten steel injection immersion nozzle is set to be greater than or equal to the effective thickness of the electromagnetic flow generated at the solidification interface. Continuous casting method.
JP6576879A 1979-05-28 1979-05-28 Continuous casting method for steel slabs Expired JPS5835784B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6576879A JPS5835784B2 (en) 1979-05-28 1979-05-28 Continuous casting method for steel slabs

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6576879A JPS5835784B2 (en) 1979-05-28 1979-05-28 Continuous casting method for steel slabs

Publications (2)

Publication Number Publication Date
JPS55158860A JPS55158860A (en) 1980-12-10
JPS5835784B2 true JPS5835784B2 (en) 1983-08-04

Family

ID=13296523

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6576879A Expired JPS5835784B2 (en) 1979-05-28 1979-05-28 Continuous casting method for steel slabs

Country Status (1)

Country Link
JP (1) JPS5835784B2 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2545588B2 (en) * 1988-09-06 1996-10-23 日新製鋼 株式会社 Casting method for ultra low carbon titanium killed steel

Also Published As

Publication number Publication date
JPS55158860A (en) 1980-12-10

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