JP2720611B2 - Steel continuous casting method - Google Patents
Steel continuous casting methodInfo
- Publication number
- JP2720611B2 JP2720611B2 JP3046951A JP4695191A JP2720611B2 JP 2720611 B2 JP2720611 B2 JP 2720611B2 JP 3046951 A JP3046951 A JP 3046951A JP 4695191 A JP4695191 A JP 4695191A JP 2720611 B2 JP2720611 B2 JP 2720611B2
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- Japan
- Prior art keywords
- mold
- wave
- continuous casting
- molten steel
- flow velocity
- Prior art date
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Description
【０００１】[0001]
【産業上の利用分野】鋳型内の溶鋼の表面流動に起因す
る鋳片欠陥の発生を防止する技術に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for preventing the occurrence of slab defects caused by the surface flow of molten steel in a mold.
【０００２】[0002]
【従来の技術と課題】連続鋳造鋳型内の溶湯の表面流速
は、パウダーの捲き込みの原因になることが知られてい
る。例えば、手嶋ら（材料とプロセス、vol.1(1988)15
5）は、鋳型内短辺近傍の湯面波高を測定して、湯面波
高と鋼板の欠陥発生率を調査して、湯面波高が大き過ぎ
ても小さ過ぎても欠陥発生率が高いという関係があるこ
とを見出した。この理由は、次のように考えることがで
きる。2. Description of the Related Art It is known that the surface flow velocity of a molten metal in a continuous casting mold causes powder entrainment. For example, Teshima et al. (Materials and Process, vol.1 (1988) 15
5) is to measure the surface wave height near the short side in the mold, investigate the surface wave height and the defect occurrence rate of the steel plate, and find that the defect occurrence rate is high even if the surface wave height is too large or too small. I found a relationship. The reason can be considered as follows.
【０００３】湯面波高が大き過ぎる場合にはパウダーを
巻き込む。久保田ら（材料とプロセス、vol.3(1990)109
8 ）が報告しているように、湯面波高と表面流速とは正
相関があり、湯面波高が大きくなると表面近傍の流速も
大きくなる。この結果溶鋼湯面上パウダーが削り込まれ
る。また、湯面の波高そのものがパウダー巻き込みの原
因であるとの報告もある（笠井ら：材料とプロセス、vo
l.3(1990)1114 ）。一方、湯面波高が小さ過ぎる場合に
は、表面付近に溶鋼が供給されず溶鋼温度が低下するた
めパウダーの溶融が不充分となり、溶鋼内部から浮上し
てきた介在物のパウダーへの溶解が困難となり、介在物
およびパウダーが湯面近傍の凝固殻に捕捉されるため、
最終製品での冷延コイルの欠陥発生率が上昇する。[0003] When the surface wave height is too large, powder is involved. Kubota et al. (Materials and Process, vol.3 (1990) 109
8) as reported by, the molten metal surface wave height and the surface velocity has a positive correlation, the greater the flow velocity near the surface when the molten metal surface wave height increases. As a result, the powder on the molten steel surface is shaved. In addition, it has been reported that the wave height itself of the molten metal surface is the cause of powder entrapment (Kasai et al .: Materials and Processes, vo
l.3 (1990) 1114). On the other hand, if the surface wave height is too small, molten steel is not supplied to the vicinity of the surface and the molten steel temperature is lowered, so that the melting of the powder becomes insufficient, and it becomes difficult to dissolve the inclusions floating from the molten steel into the powder. Since inclusions and powder are trapped in the solidified shell near the molten metal surface,
Defect rate of the cold-rolled coil in the final product is increased.
【０００４】したがって、連続鋳造鋳型内溶鋼の表面波
動に起因する鋳片の表面欠陥を低減するためには、ひと
つには、湯面波動を常時監視し、ある範囲に制御するこ
とが重要である。さらには表面流速を測定、監視するこ
とができれば、きわめて精度の高い湯面波動に起因する
鋳片の欠陥防止技術を構築することができる。Therefore, in order to reduce the surface defects of the slab due to the surface wave of the molten steel in the continuous casting mold, it is important to monitor the surface wave wave constantly and control it to a certain range. . Furthermore, if the surface flow velocity can be measured and monitored, it is possible to construct a technique for preventing a slab defect from being caused by an extremely accurate molten metal surface wave.
【０００５】溶融金属流速を測定する技術としては、低
融点合金（現在のところＡｌ合金の溶融範囲まで）に適
応できるものとして電磁流速計がある（ Ch.Vives and
R.Ricou:Met.Trans.,16B,(1985),P.377 、および細谷
ら、鉄と鋼、73(1987)S688）。しかしながら、これは電
磁コイルと静磁界発生装置（通常は永久磁石）を組合わ
せているため高融点合金（たとえば鋼、銅など）には使
用できない。As a technique for measuring the flow rate of a molten metal, there is an electromagnetic current meter which can be applied to low melting point alloys (currently up to the melting range of Al alloy) (Ch. Vives and
R. Ricou: Met. Trans., 16B, (1985), P. 377, and Hosoya et al., Iron and Steel, 73 (1987) S688). However, since this is a combination of an electromagnetic coil and a static magnetic field generator (usually a permanent magnet), it cannot be used for high melting point alloys (eg, steel, copper, etc.).
【０００６】また鈴木らの報告（鉄と鋼、68(1982)S92
0）にあるように流動している溶鋼の中へ耐火物の棒を
差し込んで、その棒にかかる力を計測したり、棒の傾き
を計測して流速を推定する方法が提示されているが、耐
火物の溶損が生じ、耐火物の棒自体が介在物の起源とな
ることなどから長時間の測定は困難である。A report by Suzuki et al. (Iron and Steel, 68 (1982) S92
There is a method of inserting a refractory rod into flowing molten steel as in 0) and measuring the force applied to the rod, or measuring the inclination of the rod to estimate the flow velocity. It is difficult to measure the refractory for a long time because the refractory melts and the refractory rod itself becomes a source of inclusions.
【０００７】このように、現在まで鋼の連続鋳造のよう
に高融点金属の流速または表面流速を長時間連続的に測
定する方法および装置は提案されていない。また、表面
流速を測定し、モニターしながら、電磁攪拌を利用して
表面流速を所定値以下に制御しながら連続鋳造を行う方
法は実現していない。As described above, up to now, there has not been proposed any method and apparatus for continuously measuring the flow rate or surface flow rate of a high melting point metal for a long time as in continuous casting of steel. Further, a method of performing continuous casting while measuring and monitoring the surface flow velocity while controlling the surface flow velocity to a predetermined value or less by using electromagnetic stirring has not been realized.
【０００８】本発明はかかる事情に鑑みてなされたもの
で、電磁攪拌によって表面流速を制御しながら鋳造する
ことのできる鋼の連続鋳造方法を提供しようとするもの
である。The present invention has been made in view of such circumstances, and has as its object to provide a continuous casting method of steel capable of casting while controlling the surface flow velocity by electromagnetic stirring.
【０００９】[0009]
【課題を解決するための手段】本発明による鋼の連続鋳
造方法は、鋳型内の溶鋼の流動を制御する電磁攪拌装置
を用い、浸漬ノズルと鋳型短辺との間で、鋳型内溶鋼表
面上の異なる位置に２個の渦流式距離計を設けてそれぞ
れ表面変動を測定し、２個の渦流式距離計からの信号を
ローパスフィルターを通した後、周波数解析装置に入力
して、この２つの測定値から相互相関関数を求め、求め
た相互相関関数から、２個の渦流式距離計の間の表面波
動の伝播速度を求め、前記伝播速度を電磁攪拌装置によ
り所定値以下に制御することを特徴とする。The continuous casting method for steel according to the present invention uses an electromagnetic stirrer for controlling the flow of molten steel in a mold, and uses an electromagnetic stirrer between a submerged nozzle and a short side of the mold to form a molten steel on the surface of the molten steel in the mold. Two eddy current rangefinders are provided at different positions of the eddy current sensor to measure the surface fluctuations respectively. The signals from the two eddy current rangefinders are passed through a low-pass filter, and then input to a frequency analysis device. obtains the cross-correlation function from the measured values, the cross-correlation functions that were determined, determine the propagation velocity of the surface wave between two vortex rangefinder controls below a predetermined value the propagation velocity by the electromagnetic stirring device It is characterized by.
【００１０】[0010]
【作用】広幅鋳片の連続鋳造鋳型内の溶鋼表面の主な流
れは、鋳型巾方向を鋳型短辺から浸漬ノズルに向かって
おり、また表面には波動がある。鋳型短辺近傍では浸漬
ノズルからの反転上昇流によって激しい溶鋼表面波動が
生じている。この反転上昇流が表面での鋳型短辺から浸
漬ノズルに向かう流れをつくっている。溶鋼表面の湯面
変動を短辺近傍とこの位置から巾方向に所定の距離離れ
たところの２ヶ所で渦流式距離計を用いて測定し、この
湯面変動の周波数解析を行い、別々の位置で測定した波
動にもかかわらず、波動を構成している周波数成分は同
じ周期の波動を含んでいることが知見された。The main flow on the surface of molten steel in the continuous casting mold of wide cast slab is from the short side of the casting mold to the immersion nozzle in the width direction of the casting mold, and the surface has waves. In the vicinity of the short side of the mold, intense molten steel surface waves are generated by the reversing upward flow from the immersion nozzle. This inverted upward flow creates a flow from the short side of the mold at the surface to the immersion nozzle. Fluctuations in the molten steel surface are measured at two locations near the short side and at a predetermined distance in the width direction from this position using an eddy current rangefinder. It was found that the frequency components constituting the wave included the wave having the same period, despite the wave measured in the above.
【００１１】このことは短辺面近傍の特定の周期をもつ
波動が浸漬ノズルの方向に伝播してきていることを示す
ものである。したがって、波動の伝播速度は上記２ヵ所
で測定された同じ周波数をもつ特定の波動に注目して、
この波動の時間遅れすなわち伝播時間を知ることによっ
て測定できる。This indicates that a wave having a specific period near the short side surface is propagating toward the immersion nozzle. Therefore, the propagation speed of the wave is calculated by focusing on the specific wave having the same frequency measured at the above two places,
It can be measured by knowing the time delay of this wave, that is, the propagation time.
【００１２】伝播時間を知るため、周波数解析装置を用
い、この２ヵ所の湯面変動の相互相関関数ＣＦを求め
た。渦流式距離計による２ヵ所の湯面変動の測定値を周
波数解析により上記特定の周波数の成分を取り出した。
この場合、上記渦流式距離計からの湯面変動の信号をロ
ーパスフィルターに入力して高周波数成分を除去してか
ら、周波数解析装置により解析する。取り出された特定
の周波数の成分をそれぞれＥ1（ｔ）、Ｅ2（ｔ）とする
と、相互相関関数ＣＦ（τ）は下記の数１により求めら
れる。In order to know the propagation time, a cross-correlation function CF of the two fluctuations of the surface level was obtained using a frequency analyzer. The components of the above specific frequency were taken out by frequency analysis of the measured values of the fluctuations of the molten metal level at two locations by the eddy current range finder.
In this case, if the input signal melt surface variation from the vortex rangefinder to the low pass filter after removing the high frequency component is analyzed by the frequency analyzer. Assuming that the extracted specific frequency components are E 1 (t) and E 2 (t), the cross-correlation function CF (τ) is obtained by the following equation (1).
【００１３】[0013]
【数１】 (Equation 1)
【００１４】数１でｔ、τはいずれも時間で、数１のｔ
に関する積分は０からＴまで行う。ＣＦ（τ）はτの周
期的な関数となるが、変動のピーク値の間隔τS が湯面
変動が測定された上記２点間の波動の伝播時間に対応す
る（図１参照）。In Equation 1, t and τ are both time.
Integration is performed from 0 to T. CF (τ) is a periodic function of τ, and the interval τ S between the peak values of the fluctuations corresponds to the propagation time of the wave between the two points at which the level change was measured (see FIG. 1).
【００１５】τS が求められると、２点間の距離をＬと
して、波の伝播速度ｖS は次の数２から計算できる。When τ S is obtained, the wave propagation velocity v S can be calculated from the following equation (2), where L is the distance between the two points.
【００１６】[0016]
【数２】 (Equation 2)
【００１７】一方、鋳型に設けられた電磁攪拌装置を用
いて浸漬ノズルからの吐出流の流速を制御して、上記の
ようにして鋳造中に求められる表面波動の伝播速度ｖS
を所定の値以下に制御することにより、表面波動に起因
する鋳片の表面欠陥を低減することができる。On the other hand, by controlling the flow velocity of the discharge flow from the immersion nozzle using an electromagnetic stirrer provided on the mold, the propagation speed v S of the surface wave required during casting as described above is determined.
Is controlled to a predetermined value or less, it is possible to reduce surface defects of the slab due to surface waves.
【００１８】[0018]
【実施例】最初に湯面波動に関する水モデルについて行
った試験について説明する。この試験は鋳型内の表面流
速と、波動の伝播速度との関係を検討するために行われ
たものである。実際の連続鋳造と同じように浸漬ノズル
を用いて水モデルの鋳型内に水を注入して、水面の波の
伝播速度を上記と同じ方法で測定および計算を行った。
このとき用いられた波動伝播計測装置は、２個の渦流式
距離計、周波数解析装置、データ処理溶演算機、ローパ
スフィルターから構成されていている。前記２個の渦流
式距離計から得られる表面波動をＥ1（ｔ）、Ｅ2（ｔ）
として、前述のようにして、相互相関関数ＣＦ（τ）を
求めた。これを図１に示す。このときの水モデルの試験
条件は、鋳型寸法は７４ｍｍｘ４００ｍｍ、浸漬ノズル
からの水の注入量は４０ｌ／ｍｉｎ、２個の渦流式距離
計の間隔は１００ｍｍである。図１から波動の伝播時間
は１．２５秒、したがって、このときの伝播速度は、８
０ｍｍ／ｓｅｃとなる。また、ローパスフィルターは、
２ＨZ 以上の周波数成分を除外するため、設定値を２Ｈ
Z とした。この理由は後述するプロペラ流速計による測
定値を周波数解析した結果、１〜２ＨZ の間の周波数の
ものが顕著なピーク値をもつことから選択したものであ
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a description will be given of a test performed on a water model related to a surface wave motion. This test was performed to examine the relationship between the surface flow velocity in the mold and the wave propagation velocity. Water was injected into the mold of the water model using an immersion nozzle in the same manner as in actual continuous casting, and the wave propagation velocity on the water surface was measured and calculated in the same manner as described above.
The wave propagation measuring device used at this time is composed of two eddy current type distance meters, a frequency analyzing device, a data processing melting computer, and a low-pass filter. The two eddies
E 1 surface wave obtained from the formula rangefinder (t), E 2 (t )
As described above, the cross-correlation function CF (τ) was obtained. This is shown in FIG. At this time, the test conditions of the water model are as follows: the mold size is 74 mm × 400 mm, the amount of water injected from the immersion nozzle is 40 l / min, and the distance between the two vortex-type distance meters is 100 mm. From FIG. 1, the propagation time of the wave is 1.25 seconds, and the propagation speed at this time is 8
0 mm / sec. Also, the low-pass filter is
To exclude 2H Z or more frequency components, the set value 2H
Z. The reason for this is that chosen because of its remarkable peak values as a frequency between the frequency analysis result, 1~2H Z measurements by a propeller anemometer that will be described later.
【００１９】また、プロペラ流速計を使って表面近傍の
流速を測定して、上記の計算による流速と比較した。図
２は水モデル試験で得られた波動の伝播速度ｖS と上記
プロペラ流速計で直接測定した表面近傍流速ｖf との関
係を示した図である。この図に示されているとおり、ｖ
S とｖf はほぼ一致しており、ｖS を測定すれば表面流
速が測定できることが知見された。Further, the flow velocity near the surface was measured using a propeller velocimeter and compared with the flow velocity calculated above. Figure 2 is a diagram showing a relationship between the near-surface velocity v f measured directly by the propagation speed v S and the propeller velocimeter wave obtained in the water model test. As shown in this figure, v
S and v f is substantially equal to, it has been found that can measure the surface flow speed by measuring the v S.
【００２０】次に実機の連続鋳造機により鋳型内の表面
流速を測定した実施例について添付の図面を参照しなが
ら説明する。図３は上記の水モデル試験に用いた波動伝
播計測装置と同様の測定機器および鋳型付近のブロック
図、図４は電磁攪拌装置の配置図を示す鋳型付近の平面
図である。図中、１１は鋳型、１２は溶鋼を鋳型内に注
入する浸漬ノズル、１３は鋳型内の溶鋼、１４は凝固殻
である。８は鋳型内の溶鋼の流動を制御する電磁攪拌装
置で、鋳型の両側に２個ずつ計４個設けてある。１６は
電磁攪拌装置を制御する電磁攪拌用制御器である。Next, an embodiment in which the surface flow velocity in the mold is measured by an actual continuous casting machine will be described with reference to the accompanying drawings. FIG. 3 is a block diagram showing the vicinity of a measuring device and a mold similar to the wave propagation measuring device used in the above-described water model test, and FIG. 4 is a plan view showing the arrangement of the electromagnetic stirring device near the mold. In the figure, 11 is a mold, 12 is an immersion nozzle for injecting molten steel into the mold, 13 is molten steel in the mold, and 14 is a solidified shell. Reference numeral 8 denotes an electromagnetic stirrer for controlling the flow of molten steel in the mold, and two electromagnetic stirrers are provided on each side of the mold, for a total of four. Reference numeral 16 denotes an electromagnetic stirring controller for controlling the electromagnetic stirring device.
【００２１】１、２は湯面変動を測定する位置に、距離
Ｌ離して設けた２個の渦流式距離計である。５は前記渦
流式距離計１、２の信号の高周波成分を除くローパスフ
ィルターである。３は２つのローパスフィルター５から
の信号が入力される周波数解析装置、４は信号処理用演
算機である。以上が鋳型内の表面波動伝播速度を測定す
る波動伝播計測装置６である。Reference numerals 1 and 2 denote two eddy current type distance meters provided at a distance L from each other at positions where the fluctuations of the molten metal level are measured. 5 is the vortex
This is a low-pass filter that removes high-frequency components of the signals of the flow type rangefinders 1 and 2. Reference numeral 3 denotes a frequency analyzer to which signals from the two low-pass filters 5 are input, and reference numeral 4 denotes a signal processing arithmetic unit. The above is the wave propagation measuring device 6 for measuring the surface wave propagation velocity in the mold.
【００２２】波動伝播計測装置６により２個の渦流式距
離計１、２により測定された湯面レベルＥ1（ｔ）とＥ2
（ｔ）から前述のようにして、相互相関関数ＣＦ（τ）
および伝播時間τs が求められ、さらに数２式からｖS
が得られる。The bath surface levels E 1 (t) and E 2 measured by the two eddy current distance meters 1 and 2 by the wave propagation measuring device 6.
From (t), as described above, the cross-correlation function CF (τ)
V S and the propagation time tau s are determined from further Equation 2
Is obtained.
【００２３】一方、電磁攪拌用制御器１６には上記のｖ
S が入力され、鋳片の表面欠陥発生率が低減されるよう
に予め定められた伝播速度ｖs0よりもｖS が小さくなる
ように、電磁攪拌装置８を用いて、浸漬ノズル１２から
吐出される溶鋼流の強さを制御する。On the other hand, the controller 16 for electromagnetic stirring
S is input, as v S is less than the propagation velocity v s0 surface defect rate of the slab is predetermined for <br/> cormorants I is reduced by using an electromagnetic stirring device 8, immersion The strength of the molten steel flow discharged from the nozzle 12 is controlled.
【００２４】次に本実施例の具体的な数値例を示す。
（試験１） 連続鋳造機に波動伝播速度計６を取付け
て、表面流速を測定した。鋳型は巾１２００ｍｍ、厚み
２２０ｍｍで、鋳片引き抜き速度は１．８〜２．６ｍ／
ｍｉｎ（鋳造速度：３．５〜５．１ｔｏｎ／ｍｉｎ）の
間で変更した。浸漬ノズルの吐出角度は下向き３５度で
ある。渦流式距離計１、２の取付け位置は鋳型短辺から
６０ｍｍと２００ｍｍ、厚み方向は中央とした。この測
定結果を図５に示す。Next, specific numerical examples of this embodiment will be shown.
(Test 1) A wave propagation velocity meter 6 was attached to a continuous casting machine, and the surface flow velocity was measured. The mold has a width of 1200 mm and a thickness of 220 mm, and the slab withdrawal speed is 1.8 to 2.6 m /.
min (casting speed: 3.5 to 5.1 ton / min). The discharge angle of the immersion nozzle is 35 degrees downward. The positions of the eddy current rangefinders 1 and 2 were set at 60 mm and 200 mm from the short side of the mold, and the thickness direction was set at the center. This measurement
The results are shown in FIG.
【００２５】図５は鋳造速度と測定した表面流速の関係
を示すもので、表面流速は測定中の最大値（Ｂ）と平均
値（Ａ）の両方を示してある。表面流速は鋳造速度の増
大とともに増大している。これに対して電磁攪拌装置８
を作動させたときの表面流速（Ｃ）も図５に示してあ
る。表面流速（Ｃ）は表面流速の増大に応じて電磁攪拌
装置８による攪拌強度すなわち電磁攪拌装置のコイル電
流を増加させて表面流速を制御した結果である。すなわ
ち、電磁攪拌力を浸漬ノズルからの溶鋼吐出流の向きと
反対方向にかけて前記溶鋼吐出流にブレーキをかけた結
果である。括弧内に示した数値は前記コイルの定格電流
を１００としたときの相対的な値である。この結果から
表面流速は電磁攪拌により低レベルでほぼ一定に制御で
きることが示される。FIG. 5 shows the relationship between the casting speed and the measured surface flow velocity. The surface flow velocity shows both the maximum value (B) and the average value (A) during the measurement. Surface flow velocity increases with increasing casting speed. On the other hand, the electromagnetic stirring device 8
5 is also shown in FIG. The surface flow velocity (C) is a result of controlling the surface flow velocity by increasing the stirring intensity of the electromagnetic stirring device 8, that is, the coil current of the electromagnetic stirring device, in accordance with the increase of the surface flow speed. That is, the result is obtained by applying a brake to the molten steel discharge flow by applying the electromagnetic stirring force in a direction opposite to the direction of the molten steel discharge flow from the immersion nozzle. The values shown in parentheses are relative values when the rated current of the coil is 100. This result indicates that the surface flow rate can be controlled to be almost constant at a low level by electromagnetic stirring.
【００２６】（試験２） 上記、試験１と同様に連続鋳
造機に波動伝播計測装置６を取付けて、表面流速を測定
したものであるが、鋳造条件として、鋳型寸法を巾１１
００ｍｍ、厚み２２０ｍｍ、鋳片引き抜き速度を２．４
ｍ／ｍｉｎで一定とした。浸漬ノズルの吐出角度は下向
き３５度である。(Test 2) The surface velocity was measured by mounting the wave propagation measuring device 6 on a continuous casting machine in the same manner as in Test 1 described above.
00 mm, thickness 220 mm, slab drawing speed 2.4
m / min. The discharge angle of the immersion nozzle is 35 degrees downward.
【００２７】図６は電磁攪拌装置８による溶鋼吐出流へ
のブレーキの強さと表面流速との関係を示している。時
系列的にコイル電流を変化させてあり、図中の数値は試
験１と同様に定格電流を１００としたときの相対的な値
である。FIG. 6 shows the relationship between the strength of the brake applied to the molten steel discharge flow by the electromagnetic stirring device 8 and the surface flow velocity. The coil current is changed in time series, and the numerical values in the figure are relative values when the rated current is set to 100 as in Test 1.
【００２８】図７は表面流速とそのとき鋳造された鋳片
から製造された冷延コイルの欠陥発生率との関係を示し
たものである。この図から表面流速が増加すると冷延コ
イルの欠陥発生率が増大することが示される。また、冷
延コイルの表面欠陥発生率の増大をもたらす表面流速は
２０ｃｍ／ｓｅｃ以上であることを示している。FIG. 7 shows the relationship between the surface flow velocity and the defect occurrence rate of a cold-rolled coil manufactured from a slab cast at that time. This figure shows that as the surface flow velocity increases, the defect occurrence rate of the cold-rolled coil increases. It also shows that the surface flow rate that causes an increase in the incidence of surface defects of the cold-rolled coil is 20 cm / sec or more.
【００２９】（試験３） 波動伝播計測装置６で測定さ
れた表面流速に応じて、電磁攪拌装置８でコイル電流を
調整しながら、表面流速を２０ｃｍ／ｓｅｃ未満に自動
制御したもので、鋳造条件として、鋳型寸法を巾１２０
０ｍｍ、厚み２２０ｍｍ、鋳片引き抜き速度を２．４ｍ
／ｍｉｎで一定とし、浸漬ノズルの吐出角度は下向き３
５度である。(Test 3) The surface flow velocity was automatically controlled to less than 20 cm / sec while adjusting the coil current with the electromagnetic stirrer 8 in accordance with the surface flow velocity measured by the wave propagation measuring device 6. The width of the mold is 120
0mm, thickness 220mm, slab drawing speed 2.4m
/ Min and the discharge angle of the immersion nozzle is downward 3
5 degrees.
【００３０】上記の条件で、鋳造中の表面流速の時間的
変化を図８に示した。電磁攪拌の自動制御作動の有無も
図中に示してある。約２時間にわたって、上記波動伝播
計測装置６、表面流速電磁攪拌装置８および電磁攪拌用
制御器１６による自動制御を行い、このときの鋳片から
製造された冷延コイルの表面欠陥発生率は０．５％以下
で、この値は従来の１／３以下である。FIG. 8 shows the change over time of the surface flow velocity during casting under the above conditions. The presence or absence of the automatic control operation of the electromagnetic stirring is also shown in the figure. Automatic control by the wave propagation measurement device 6, the surface flow velocity electromagnetic stirrer 8 and the electromagnetic stirrer controller 16 was performed for about 2 hours, and the surface defect occurrence rate of the cold rolled coil manufactured from the slab was 0 at this time. At 0.5% or less, this value is 1/3 or less of the conventional value.
【００３１】[0031]
【発明の効果】本発明によれば、鋳型内の表面波動の伝
播速度が鋳造中に測定され、この測定値に基づいて鋳型
に設けられた電磁攪拌装置により、上記伝播速度を制御
するので、鋳片の表面欠陥の発生率が低減される。According to the present invention, the propagation speed of the surface wave in the mold is measured during casting, and the propagation speed is controlled by the electromagnetic stirring device provided in the mold based on the measured value. The incidence of surface defects on the slab is reduced.
【図１】相互相関関数と時間との関係を示すグラフ図で
ある。FIG. 1 is a graph showing a relationship between a cross-correlation function and time.
【図２】水モデル試験による本実施例とプロペラ流速計
による波動伝播速度を比較したグラフ図である。FIG. 2 is a graph showing a comparison between a wave propagation velocity measured by a propeller velocimeter and the present embodiment based on a water model test.
【図３】本実施例の連続鋳造機の鋳型内の溶鋼表面波動
を測定するブロック図である。FIG. 3 is a block diagram for measuring a surface wave of molten steel in a mold of the continuous casting machine of the present embodiment.
【図４】本実施例の鋳型付近の電磁攪拌装置の配置を示
す平面図である。FIG. 4 is a plan view showing an arrangement of an electromagnetic stirring device near a mold according to the present embodiment.
【図５】本実施例の鋳造速度と表面流速との関係を示す
グラフ図である。FIG. 5 is a graph showing a relationship between a casting speed and a surface flow speed in the present embodiment.
【図６】本実施例の表面流速の時間的変化を示すグラフ
図である。FIG. 6 is a graph showing a temporal change of the surface flow velocity in the present embodiment.
【図７】本実施例の表面流速と冷延コイル欠陥発生率と
の関係を示すグラフ図である。FIG. 7 is a graph showing the relationship between the surface flow velocity and the incidence rate of cold-rolled coil defects in this example.
【図８】本実施例の表面流速の電磁攪拌を作動させたと
きの時間的変化を示すグラフ図である。FIG. 8 is a graph showing a temporal change when electromagnetic stirring of the surface flow velocity is operated in the present embodiment.
１、２ 渦流式距離計 ３ 周波数解析装置 ４ データ処理用演算機 ５ ローパスフィルター ６ 波動伝播計測装置 ７ 電磁攪拌制御器 ８ 電磁攪拌装置 １１ 鋳型 １２ 浸漬ノズル １３ 溶鋼 １４ 凝固殻1, 2 Eddy current rangefinder 3 Frequency analyzer 4 Data processing computer 5 Low pass filter 6 Wave propagation measuring device 7 Electromagnetic stirring controller 8 Electromagnetic stirring device 11 Mold 12 Immersion nozzle 13 Molten steel 14 Solidified shell
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平２−307656（ＪＰ，Ａ) 特開 昭62−190469（ＪＰ，Ａ) 特開 昭62−197255（ＪＰ，Ａ) ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-307656 (JP, A) JP-A-62-190469 (JP, A) JP-A-62-197255 (JP, A)
Claims (2)
装置を用い、浸漬ノズルと鋳型短辺との間で、溶鋼表面
上の異なる位置に２個の渦流式距離計を設けてそれぞれ
表面変動を測定し、２個の渦流式距離計からの信号をロ
ーパスフィルターを通した後、周波数解析装置に入力し
て、この２つの測定値から相互相関関数を求め、求めた
相互相関関数から、２個の渦流式距離計の間の表面波動
の伝播速度を求め、前記伝播速度を電磁攪拌装置により
所定値以下に制御することを特徴とする鋼の連続鋳造方
法。An electromagnetic stirrer for controlling the flow of molten steel in a mold is provided. Two eddy current distance meters are provided at different positions on the surface of the molten steel between an immersion nozzle and a short side of the mold, and each has a surface. the variation is measured, the signals from the two vortex rangefinder passed through a low pass filter, and input to the frequency analyzer obtains the cross-correlation function of the two measurements, the cross-correlation function number from the obtained 2. A continuous casting method for steel, comprising: determining a propagation speed of a surface wave between two eddy current rangefinders, and controlling the propagation speed to a predetermined value or less by an electromagnetic stirrer.
スフィルターを通し、２Ｈｚ以上の周波数成分を除去す
ることを特徴とする請求項１に記載の鋼の連続鋳造方
法。2. The continuous casting method for steel according to claim 1 , wherein the signals from the two eddy current rangefinders are passed through a low-pass filter to remove frequency components of 2 Hz or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3046951A JP2720611B2 (en) | 1991-03-12 | 1991-03-12 | Steel continuous casting method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3046951A JP2720611B2 (en) | 1991-03-12 | 1991-03-12 | Steel continuous casting method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04284956A JPH04284956A (en) | 1992-10-09 |
| JP2720611B2 true JP2720611B2 (en) | 1998-03-04 |
Family
ID=12761602
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3046951A Expired - Fee Related JP2720611B2 (en) | 1991-03-12 | 1991-03-12 | Steel continuous casting method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2720611B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101047826B1 (en) * | 2002-11-29 | 2011-07-08 | 에이비비 에이비 | Control systems, computer program products, apparatus and methods |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1077470C (en) * | 1994-03-07 | 2002-01-09 | 新日本制铁株式会社 | Continuous casting and appts. |
| EP0832704A1 (en) * | 1996-09-19 | 1998-04-01 | Hoogovens Staal B.V. | Continuous casting machine |
| WO2000051762A1 (en) | 1999-03-02 | 2000-09-08 | Nkk Corporation | Method and device for predication and control of molten steel flow pattern in continuous casting |
| JP5083241B2 (en) * | 2009-02-06 | 2012-11-28 | 住友金属工業株式会社 | Steel continuous casting method and slab manufactured by this method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62190469A (en) * | 1986-02-17 | 1987-08-20 | Mitsubishi Heavy Ind Ltd | Measuring instrument for jet speed of liquid |
| JPH0780039B2 (en) * | 1986-02-21 | 1995-08-30 | 川崎製鉄株式会社 | A method for detecting drift of molten steel into the mold during continuous casting. |
| JPH02307656A (en) * | 1989-05-22 | 1990-12-20 | Sumitomo Metal Ind Ltd | Continuous casting method |
-
1991
- 1991-03-12 JP JP3046951A patent/JP2720611B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101047826B1 (en) * | 2002-11-29 | 2011-07-08 | 에이비비 에이비 | Control systems, computer program products, apparatus and methods |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04284956A (en) | 1992-10-09 |
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