JP3298523B2 - Metal surface level control method for continuous casting - Google Patents
Metal surface level control method for continuous castingInfo
- Publication number
- JP3298523B2 JP3298523B2 JP30875798A JP30875798A JP3298523B2 JP 3298523 B2 JP3298523 B2 JP 3298523B2 JP 30875798 A JP30875798 A JP 30875798A JP 30875798 A JP30875798 A JP 30875798A JP 3298523 B2 JP3298523 B2 JP 3298523B2
- Authority
- JP
- Japan
- Prior art keywords
- level
- molten metal
- hot water
- time
- water supply
- 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.)
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- Continuous Casting (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、連続鋳造の鋳造開
始に際し、鋳型内への給湯開始から鋳片の引抜き開始に
至るまでの湯面レベル制御方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a metal surface level from the start of hot water supply into a mold to the start of drawing of a slab when starting continuous casting.
【０００２】[0002]
【従来の技術】連続鋳造機の鋳造開始にあたっては、ま
ず鋳型にダミーバーヘッドを装着し、鋳型の下端部を閉
じておく。タンディッシュ下部に設けた給湯制御弁を全
閉とし、取鍋からタンディッシュ内に溶湯を注入し、一
定量の溶湯が溜まったとき、タンディッシュ下部の給湯
制御弁を開き、鋳型に溶湯を注入する。鋳型に注入され
た溶湯は鋳型壁に接する面から冷却され、凝固シェルが
順次生成されてゆく。この凝固シェルが所定の厚さにな
るとともに、鋳型内湯面が予め設定されたレベルに達し
たときダミーバーの引き抜きを開始する。鋳型への溶湯
の注入開始からダミーバー引抜き開始までの時間を保持
時間という。前記給湯制御弁はストッパ方式またはスラ
イディングノズル方式が代表的なものである。2. Description of the Related Art When starting casting of a continuous casting machine, a dummy bar head is first mounted on a mold, and the lower end of the mold is closed. Fully close the hot water supply control valve provided at the bottom of the tundish, pour the molten metal from the ladle into the tundish, and when a certain amount of molten metal has accumulated, open the hot water supply control valve at the bottom of the tundish and inject the molten metal into the mold I do. The molten metal injected into the mold is cooled from the surface in contact with the mold wall, and solidified shells are sequentially generated. When the solidified shell reaches a predetermined thickness and the level of the molten metal in the mold reaches a preset level, the pulling out of the dummy bar is started. The time from the start of the injection of the molten metal into the mold to the start of the pulling out of the dummy bar is called a holding time. The hot water supply control valve is typically of a stopper type or a sliding nozzle type.
【０００３】前記の保持時間が少なすぎると凝固シェル
の生成が不十分となって、鋳片を鋳型から引抜いていく
ときに凝固シェルが破断することがあり、溶湯が溢流し
てブレークアウトと称する事故につながる。一方、保持
時間が過大になると、給湯流量が少なくなり、給湯制御
弁の流路や浸漬ノズル内で溶湯が凝固、閉塞し、操業を
停止せざるをえなくなる。従って、保持時間を適正に保
つことが操業安定上重要である。[0003] If the holding time is too short, the formation of a solidified shell is insufficient, and the solidified shell may be broken when the slab is pulled out of the mold, and the molten metal overflows and is called breakout. It leads to an accident. On the other hand, if the holding time is too long, the flow rate of the hot water supply decreases, and the molten metal solidifies and blocks in the flow path of the hot water supply control valve and the immersion nozzle, so that the operation must be stopped. Therefore, it is important to maintain the holding time properly for stable operation.
【０００４】この対策として、例えば特公平２−５１６
９９号公報には、凝固シェルの生成速度から必要な保持
時間を求め、該保持時間後に湯面が所定レベルに達する
ような湯上がりパターンを設定し、注湯開始後、湯面が
中間確認レベルに達したとき、前記保持時間を確保でき
るように設定湯上がりパターンを修正し、以後、この修
正された湯上がりパターンを保持するように溶鋼の流量
を制御する方法が開示されている。As a countermeasure, for example, Japanese Patent Publication No. 2-516
In Japanese Patent No. 99, the required holding time is determined from the generation speed of the solidified shell, and a rising pattern is set such that the molten metal level reaches a predetermined level after the holding time. A method is disclosed in which when the temperature reaches, the set hot water pattern is corrected so as to secure the holding time, and thereafter, the flow rate of molten steel is controlled so as to hold the corrected hot water pattern.
【０００５】また、特開平５−３２９６０５号公報に
は、注湯開始時点から湯面レベルを鋳片引抜き速度に相
当する上昇速度になるよう制御し、引抜き開始（すなわ
ちピンチロール起動）後、定常状態の湯面レベルになる
まで、ランプ状の湯面上昇パターンに沿って湯面レベル
自動制御を行う方法が開示されている。Japanese Patent Application Laid-Open No. 5-329605 discloses that the level of a molten metal is controlled to a rising speed corresponding to the speed of drawing a slab from the start of pouring. There is disclosed a method of performing automatic control of a metal level along a ramp-shaped metal level rise pattern until the metal level reaches a state.
【０００６】[0006]
【発明が解決しようとする課題】前記の特公平２−５１
６９９号公報に開示された方法は、保持時間の確保を優
先するため、ピンチロール起動時の鋳造速度と湯面レベ
ル上昇速度がバランスされておらず、湯面レベル変動を
引き起こす恐れがある。Problems to be Solved by the Invention
In the method disclosed in Japanese Patent Application Laid-Open No. 699, since the priority is given to securing the holding time, the casting speed at the time of starting the pinch roll and the rising level of the molten metal level are not balanced, and there is a possibility that the molten metal level may fluctuate.
【０００７】また、特開平５−３２９６０５号公報に開
示された方法は、ピンチロール起動時の引抜き速度で湯
面レベルの目標値を上昇させる位置フィードバック制御
であるため、目標値の上昇速度と等しい速度で湯面が上
昇したとしても、湯面レベル値自体が目標の湯面レベル
に対して偏差があると給湯制御弁の開度を修正すること
になり、結果として湯面上昇速度のバランスを崩してし
まう。とくに目標レベルの上昇速度、つまりピンチロー
ルの起動時の引抜き速度が高速になると（例えば、中厚
スラブ連続鋳造機では０．８ｍ／ｍｉｎ以上）、問題が
顕著になり、大きな湯面変動が発生し操業を阻害する恐
れがある。The method disclosed in Japanese Patent Application Laid-Open No. Hei 5-329605 is a position feedback control in which the target value of the metal level is increased at the pulling speed at the time of starting the pinch roll. Even if the level rises at the speed, if the level of the level itself deviates from the target level, the opening of the hot water supply control valve will be corrected. Will break down. In particular, when the rising speed of the target level, that is, the drawing speed at the time of starting the pinch roll becomes high (for example, 0.8 m / min or more in the case of a medium-thickness slab continuous casting machine), the problem becomes remarkable, and a large fluctuation in the molten metal surface occurs. Operation may be hindered.
【０００８】[0008]
【課題を解決するための手段】発明者らは前記の従来技
術の問題を検討し、以下の知見を得た。 (a) 保持時間は前記特公平２−５１６９９号公報のよう
に厳密に管理する必要はなく、ある程度幅を持った管理
範囲内にあればよい。Means for Solving the Problems The present inventors have examined the above-mentioned problems of the prior art and obtained the following findings. (a) The holding time need not be strictly controlled as in the above-mentioned Japanese Patent Publication No. 2-51699, but may be within a management range having a certain width.
【０００９】(b) 鋳型への注湯開始直後は鋳型が冷えて
いること、ダミーバーヘッドからの抜熱があること、等
から元々非定常過程であり、凝固シェルも厚く微妙な制
御は不要である。(B) Immediately after the start of pouring into the mold, it is originally an unsteady process due to the fact that the mold is cold, heat is removed from the dummy bar head, etc. The solidified shell is thick and requires no delicate control. is there.
【００１０】(c) これに対して、ピンチロール引抜き開
始直前で鋳型への給湯流量が変動すると、凝固シェル厚
さが変動し、局部的に薄い部分が起点になってブレーク
アウトの原因になる。従って、この時点では給湯制御弁
の開度を一定とするのがよい。ピンチロール引抜き開始
までの非定常の過程で自動制御系による湯面レベル制御
または湯面レベル上昇速度制御を行うと、給湯流量が大
きく変動するので好ましくない。(C) On the other hand, if the flow rate of the hot water supplied to the mold fluctuates immediately before the start of the pinch roll drawing, the thickness of the solidified shell fluctuates, and a locally thin portion becomes a starting point and causes a breakout. . Therefore, at this time, the opening of the hot water supply control valve should be kept constant. If the level control or the level rising speed control by the automatic control system is performed in the unsteady process until the start of the pinch roll withdrawal, it is not preferable because the flow rate of the hot water supply largely varies.
【００１１】(d) タンディッシュから鋳型への注湯開始
の直後は給湯制御弁の固着、溶湯の一部凝固などで弁開
度と流量の関係は不安定であるが、一定時間または一定
量の溶湯が通過した後は弁開度と流量の関係が安定す
る。この時点では弁開度変更に伴う給湯流量の変化量の
推定が可能であり、保持時間の確保に必要な給湯流量を
得られるように弁開度を修正することが可能である。(D) Immediately after the start of pouring from the tundish into the mold, the relationship between the valve opening degree and the flow rate is unstable due to sticking of the hot water supply control valve and partial solidification of the molten metal. After the molten metal has passed, the relationship between the valve opening and the flow rate is stabilized. At this point, it is possible to estimate the amount of change in the hot water flow rate due to the change in the valve opening degree, and it is possible to modify the valve opening degree so as to obtain the hot water flow rate necessary for securing the holding time.
【００１２】(e) ピンチロール引抜き開始直前では引抜
き速度とバランスする湯面レベル上昇速度を得ることが
重要になる。この時点でもやはり、弁開度と給湯流量の
変化量の推定が可能であり、所定の湯面レベル上昇速度
を得られるように弁開度を修正することが可能である。(E) Immediately before the start of pinch roll drawing, it is important to obtain a level rise level that is balanced with the drawing speed. Even at this point, it is possible to estimate the amount of change between the valve opening degree and the flow rate of hot water supply, and it is possible to modify the valve opening degree so as to obtain a predetermined level rise level.
【００１３】(f) ピンチロールで引抜き開始される時の
湯面レベルは定常鋳造時の湯面レベルよりわずかに低位
である。ピンチロールの速度が徐々に上昇する間に湯面
レベルは定常鋳造時のレベルに達し、この時点から自動
制御モードに投入すれば、設定切り替えによる制御変動
を最小限にすることができる。(F) The level of the molten metal when the drawing is started with a pinch roll is slightly lower than the level of the molten metal during steady casting. While the speed of the pinch roll gradually increases, the level of the molten metal reaches the level at the time of steady casting, and if the automatic control mode is entered from this point, control fluctuations due to setting switching can be minimized.
【００１４】本発明は上記の知見に基づいてなされたも
ので、その要旨は、「連続鋳造機の鋳造開始に際し、下
記の手順の操作を行うことを特徴とする連続鋳造の湯面
レベル制御方法。The present invention has been made based on the above findings, and the gist of the invention is "a method of controlling the surface level of continuous casting, characterized by performing the following procedure at the start of casting by a continuous casting machine. .
【００１５】(1) タンディッシュから鋳型への給湯制御
弁を所定の開度に設定し、給湯する。(1) The hot water supply control valve from the tundish to the mold is set at a predetermined opening degree to supply hot water.
【００１６】(2) 鋳型内の湯面が所定のレベルに達した
とき、所定の時間、湯面レベルを計測し、湯面レベルの
上昇速度を求める。この時の湯面レベルの上昇速度と、
湯面レベルとから、給湯開始から引抜き開始時の所定湯
面レベルに至るまでの保持時間を推定する。前記推定保
持時間が目標保持時間管理値の上限を超えるときは上限
との時間差をなくすように、下限未満のときは下限との
時間差をなくすように前記給湯制御弁の開度を修正す
る。(2) When the level of the molten metal in the mold reaches a predetermined level, the level of the molten metal is measured for a predetermined period of time, and the rate of rise of the level of the molten metal is determined. At this time, the rising level of the bath level,
The holding time from the start of hot water supply to the predetermined level at the start of drawing is estimated from the level of the molten metal. When the estimated holding time exceeds the upper limit of the target holding time management value, the opening degree of the hot water supply control valve is corrected so as to eliminate the time difference from the upper limit, and when the estimated holding time is less than the lower limit, to eliminate the time difference from the lower limit.
【００１７】(3) 湯面が前記(2) の所定レベルよりさら
に上位の所定レベルに達したとき、湯面レベルの上昇速
度が起動時のピンチロールの引抜き速度と同じになるよ
うに前記給湯制御弁の開度を変更する。(3) When the level of the molten metal reaches a predetermined level higher than the predetermined level of (2), the hot water supply is performed so that the rising speed of the molten metal level becomes the same as the pull-out speed of the pinch roll at the time of starting. Change the opening of the control valve.
【００１８】(4) 湯面が前記(3) の所定レベルよりさら
に上位の所定レベルに達したとき、鋳片の引き抜きを開
始する」にある。(4) When the molten metal surface reaches a predetermined level higher than the predetermined level of (3), the drawing of the slab is started. "
【００１９】[0019]
【発明の実施の形態】図１は本発明の制御方法を実施す
るための装置の構成図である。同図において、タンディ
ッシュ１の溶湯２は給湯制御弁３の開度によって給湯流
量を調整され、浸漬ノズル４を経由して、鋳型５内に供
給される。鋳型の下部にはダミーバー６が装入されてお
り、鋳型５内の溶湯レベルは鋳型５の上方に設置された
湯面レベル計７により計測され、その計測値は湯面レベ
ル制御装置８に入力される。湯面レベル制御装置８は湯
面レベルが上昇するにつれて適時計算し、給湯制御弁３
の開度を制御し、あるいはピンチロール９の回転速度を
制御するピンチロール制御装置１０に起動指令を出力す
る。FIG. 1 is a block diagram of an apparatus for implementing a control method of the present invention. In the figure, the flow rate of the molten metal 2 of the tundish 1 is adjusted by the opening degree of the hot water supply control valve 3, and supplied into the mold 5 via the immersion nozzle 4. A dummy bar 6 is inserted in the lower part of the mold, and the level of the molten metal in the mold 5 is measured by a level gauge 7 installed above the mold 5, and the measured value is input to a level controller 8. Is done. The water level control device 8 performs timely calculation as the level rises, and the hot water supply control valve 3
The start command is output to a pinch roll control device 10 that controls the opening of the pinch roll or controls the rotation speed of the pinch roll 9.
【００２０】図２は本発明の制御方法による鋳造速度、
給湯制御弁開度および湯面レベルの変化を示すタイムチ
ャートである。FIG. 2 shows the casting speed according to the control method of the present invention,
It is a time chart which shows a change of a hot-water supply control valve opening degree and a hot-water level.
【００２１】図３は本発明の制御方法の手順を示すフロ
ーチャートである。以下、同図のフローチャート上の処
理ステップをＳ１、Ｓ２・・・のように記述する。FIG. 3 is a flowchart showing the procedure of the control method of the present invention. Hereinafter, the processing steps in the flowchart of FIG. 3 are described as S1, S2,.
【００２２】図２に示すように、給湯開始の直前は給湯
制御弁は全閉とし、所定量の溶湯がタンディッシュに蓄
積される。その後、次のように本発明の制御方法の手順
を実行する。As shown in FIG. 2, immediately before the start of hot water supply, the hot water supply control valve is fully closed, and a predetermined amount of molten metal is accumulated in the tundish. Then, the procedure of the control method of the present invention is executed as follows.
【００２３】第１手順：給湯開始後、後述の所定の湯面
レベルＬ1 （ｍｍ）に達するまで、給湯制御弁を一定の
開度で維持してもよいが、通常の作業では下記のような
操業を行なう。First procedure: After starting hot water supply, the hot water supply control valve may be maintained at a constant opening until a predetermined hot water level L 1 (mm) described later is reached. Operation.
【００２４】給湯開始と同時に湯面レベル制御装置によ
って、給湯制御弁は予め設定された開度Ｘ1 （％）で所
定のＴX1（ｓ）の時間「開」にされる。この時の開度Ｘ
1 は給湯制御弁の溶湯凝固による詰まりを防止するた
め、可能な限り全開とするのが好ましい。At the same time as the start of hot water supply, the hot water level control device opens the hot water supply control valve at a predetermined opening degree X 1 (%) for a predetermined time T X1 (s). Opening X at this time
In order to prevent clogging of the hot water supply control valve due to solidification of the molten metal, it is preferable to open the valve 1 as much as possible.
【００２５】所定時間ＴX1後、給湯制御弁の開度をＸ2
（％）まで絞る。この開度Ｘ2 は引抜き開始までの保持
時間の前半部を決定する開度であり、経験的に得られて
いる弁開度と流量の関係（給湯制御弁のゲインＫ）に従
って、予め湯面レベル制御装置に設定された値である。
以上の処理は図３のフローチャートではステップ１（Ｓ
１）に対応する。After a predetermined time T X1 , the opening of the hot water supply control valve is changed to X 2
(%). The degree of opening X 2 is opening for determining the first half of the retention time to pull the start, according to empirically obtained by which the valve opening degree and flow rate relationship (gain K of the hot water supply control valves), previously hot surface This is a value set in the level control device.
The above processing is performed in step 1 (S
This corresponds to 1).
【００２６】第２手順：湯面レベルが所定のレベルＬ1
に達したとき、この時の時刻ｔ1 （ｓ）と湯面レベルＬ
1 （ｍｍ）を記憶する。この処理は、図３のＳ２、Ｓ３
に対応する。Second procedure: The level of the molten metal is a predetermined level L 1
Is reached, the time t 1 (s) at this time and the surface level L
1 (mm) is stored. This processing is performed in steps S2 and S3 in FIG.
Corresponding to
【００２７】更に、湯面レベルが所定のレベルＬ2 に達
したとき、この時の時刻ｔ2 （ｓ）と 湯面レベルＬ2
（ｍｍ）を記憶する。この処理は図３のＳ４、Ｓ５に対
応する。Further, when the molten metal level reaches a predetermined level L 2 , the time t 2 (s) at this time and the molten metal level L 2
(Mm) is stored. This processing corresponds to S4 and S5 in FIG.
【００２８】このｔ2 時点で、残り保持時間の予測、お
よび所定保持時間を確保するため給湯制御弁の開度修正
を下記のように行う。At time t 2 , the remaining holding time is predicted, and the opening of the hot water supply control valve is corrected as described below to secure the predetermined holding time.
【００２９】Ｌ3 （ｍｍ）をピンチロール引抜き開始
（保持時間終了）時点で達成すべき湯面レベルとする
と、 湯面上昇速度（ｍｍ／ｓ）：ＶL2は、 ＶL2＝（Ｌ2 −Ｌ1 ）／（ｔ2 −ｔ1 ） (1) 推定保持時間（ｓ）：Ｔholdは、 Ｔhold＝ｔ2 ＋（Ｌ3 −Ｌ2 ）／ＶL2 （２） として求める。これらの処理は図３のＳ６に対応する。[0029] When L 3 (mm) of the pinch rolls pull start (retention time End) molten metal surface level to be achieved at the time, water level rise velocity (mm / s): V L2 is, V L2 = (L 2 - L 1 ) / (t 2 −t 1 ) (1) Estimated holding time (s): T hold is obtained as T hold = t 2 + (L 3 −L 2 ) / V L2 (2) These processes correspond to S6 in FIG.
【００３０】上記の推定保持時間Ｔｈｏｌｄが予め設定
した目標保持時間の下限値Ｔsrt （最短保持時間とい
う）より短い場合は、Ｔsrt 以上の保持時間を確保する
ため、下記(3) の所要湯面レベル上昇速度Ｖhold（ｍｍ
／ｓ）より、給湯制御弁の開度Ｘ3（％）を下記(4) の
ように求める、 Ｖhold＝（Ｌ3 −Ｌ2 ）／（Ｔsrt −ｔ2 ） (3) Ｘ3 ＝Ｖhold／Ｋ (4) これらの処理は図３のＳ７、Ｓ８、Ｓ９、Ｓ１５に対応
する。If the above-mentioned estimated holding time T hold is shorter than a preset lower limit value T srt of the target holding time (referred to as the shortest holding time), the following condition (3) is required to secure the holding time longer than T srt. Level level rise V hold (mm
/ S), the opening degree X 3 (%) of the hot water supply control valve is obtained as shown in the following (4). V hold = (L 3 −L 2 ) / (T srt −t 2 ) (3) X 3 = V hold / K (4) These processes correspond to S7, S8, S9, S15 in FIG.
【００３１】逆に、Ｔholdが予め設定した目標保持時間
の上限値Ｔlng （最長保持時間という）より長い場合
は、Ｔlng 以下の保持時間とするため、下記(5) の所要
湯面レベル上昇速度Ｖhold（ｍｍ／ｓ）より、給湯制御
弁の開度Ｘ3 （％）を下記(6)のように求める、 Ｖhold＝（Ｌ3 −Ｌ2 ）／（Ｔlng −ｔ2 ） (5) Ｘ3 ＝Ｖhold／Ｋ (6) これらの処理は図３のＳ１０、Ｓ１１、Ｓ１２、Ｓ１５
に対応する。Conversely, if T hold is longer than the preset upper limit value T lng (referred to as the longest holding time) of the target holding time, in order to set the holding time to T lng or less, the required surface level of (5) From the rising speed V hold (mm / s), the opening degree X 3 (%) of the hot water supply control valve is obtained as in the following (6). V hold = (L 3 −L 2 ) / (T lng −t 2 ) (5) X 3 = V hold / K (6) These processes are performed in S10, S11, S12, and S15 in FIG.
Corresponding to
【００３２】ＴholdがＴsrt とＴlng の間にあるとき
は、現状の開度で適正な保持時間が確保できるとし、給
湯制御弁の開度はＸ2 のままに保持する。この処理は図
３のＳ１３、Ｓ１４、Ｓ１５に対応する。When T hold is between T srt and T lng , it is determined that an appropriate holding time can be secured at the current opening, and the opening of the hot water supply control valve is maintained at X 2 . This processing corresponds to S13, S14, and S15 in FIG.
【００３３】ここで、Ｋは給湯制御弁のゲイン（湯面上
昇速度（ｍｍ／ｓ）／給湯制御弁の開度（％））であ
り、予め鋳造試験により求められた値である。もしく
は、ｔ2の時点で判明している最新の実測値、すなわ
ち、Ｋ＝ＶL2／Ｘ2 として求めてもよい。Here, K is the gain of the hot water supply control valve (the rising level of the hot water (mm / s) / the opening degree (%) of the hot water supply control valve), which is a value previously obtained by a casting test. Alternatively, it may be obtained as the latest actually measured value that is known at the time point of t 2 , that is, K = V L2 / X 2 .
【００３４】第３手順：その後さらに湯面レベルが上昇
してＬ3 （ｍｍ）に至ったとき（この時の時刻をｔ3 と
する）、ピンチロールを起動したときの引抜き速度Ｖ0
と同じ湯面レベル上昇速度が得られるように給湯制御弁
の開度ＸV0（これをバランス開度という）を以下のよう
に算出し設定する。Third procedure: After that, when the molten metal level further rises and reaches L 3 (mm) (time at this time is t 3 ), the pulling speed V 0 when the pinch roll is activated.
The opening X V0 of the hot water supply control valve (this is referred to as a balance opening) is calculated and set as follows so that the same level of rising of the molten metal level can be obtained.
【００３５】ｔ3 時点での湯面レベル上昇速度ＶL3は
(7) 式で与えられ、 ＶL3＝（Ｌ3 −Ｌ2 ）／（ｔ3 −ｔ2 ） (7) 最新の給湯制御弁のゲインは(8) 式で与えられるので、 Ｋ＝（ＶL3−ＶL2）／（Ｘ3 −Ｘ2 ） (8) 狙いの湯面レベル上昇速度Ｖ0 を得るための給湯制御弁
の開度は(9) 式で与えられる、 ＸV0＝（Ｖ0 −ＶL3）／Ｋ＋Ｘ3 (9) 。The level rise rate V L3 at the time t 3 is
V L3 = (L 3 −L 2 ) / (t 3 −t 2 ) (7) Since the latest gain of the hot water supply control valve is given by the expression (8), K = (V L3− V L2 ) / (X 3 −X 2 ) (8) The opening degree of the hot water supply control valve for obtaining the target level rising speed V 0 is given by the following equation (9): X V0 = (V 0 −V L3 ) / K + X 3 (9).
【００３６】この操作は、ピンチロール起動直前の処理
であって、ピンチロール引抜き開始時点で、給湯制御弁
の開度変化なしに湯面レベルが一定になるようにするも
のである。すなわち、あらかじめ湯面レベルの上昇速度
を起動時のピンチロール引き抜き速度と同じにしておけ
ば、実際にピンチロールを起動したとき両者がバランス
し、湯面レベルは一定値を保つようになる。これらの処
理は図３のＳ１６〜Ｓ１８に相当する。This operation is a process immediately before the start of the pinch roll. At the time of starting the pinch roll withdrawal, the level of the molten metal is kept constant without changing the opening of the hot water supply control valve. That is, if the rising speed of the molten metal level is set in advance to be the same as the pinch roll withdrawing speed at the time of activation, when the pinch rolls are actually activated, the two are balanced and the molten metal level is maintained at a constant value. These processes correspond to S16 to S18 in FIG.
【００３７】第４手順：さらに湯面レベルが上昇しＬV0
に至ったとき、湯面レベル制御装置はピンチロール引抜
き制御装置に起動指令を出力し、鋳片の引き抜きが開始
される。引抜き速度は機械装置の特性から決まる起動時
間経過後に一定速度となるが、第３手順による給湯制御
弁開度の設定が適切であれば、この間湯面レベルは順次
上昇速度が低下し、引抜き速度が一定になるとともに、
湯面レベルは一定になる。これらの処理は図３のＳ１
９、Ｓ２０に相当する。Fourth procedure: The level of the molten metal rises further and L V0
Is reached, the molten metal level control device outputs a start command to the pinch roll removal control device, and the removal of the slab is started. The withdrawal speed becomes constant after the elapse of the startup time determined by the characteristics of the mechanical device. However, if the setting of the opening degree of the hot water supply control valve according to the third procedure is appropriate, the level of the molten metal level gradually decreases during this time, and the withdrawal speed Becomes constant,
The level of the bath surface is constant. These processes are performed in S1 of FIG.
9, S20.
【００３８】以上の第１〜第４の手順により目標保持時
間の上下限範囲内の保持時間が得られる。With the above-described first to fourth procedures, a holding time within the upper and lower limits of the target holding time can be obtained.
【００３９】引抜き開始後は一定の時間後、定常鋳造状
態での湯面レベルＬr を目標値とした湯面レベル一定制
御に移行する。この処理は図３のＳ２１に対応する。[0039] After withdrawal started after a certain time, the process proceeds to molten metal surface level control that is a target value of the molten metal surface level L r at steady casting state. This process corresponds to S21 in FIG.
【００４０】上記の第４手順において、ピンチロール引
抜き速度、すなわち鋳造速度が一定になったときに湯面
レベルが一定となり、かつそのレベルが定常状態での目
標湯面レベルＬr に一致していれば、定常状態での湯面
レベル一定制御に大きな変動なしに（バンプレス）移行
でき、理想的である。しかし、引き抜き速度が一定にな
り、湯面レベルが一定になったとき、必ずしもその湯面
レベルが目標湯面レベルＬr に一致しているとは限らな
い。[0040] In a fourth procedure described above, the pinch roll drawing speed, i.e. molten metal surface level is constant when the casting speed is constant, and has its level equal to the target melt-surface level L r at steady state If this is the case, it is possible to make a transition to (bumpless) the constant control of the molten metal level in a steady state without a large change, which is ideal. However, now drawing speed is constant, when the molten metal surface level becomes constant it does not necessarily follow that molten metal surface level is equal to the target melt-surface level L r.
【００４１】このような場合の対応として、上記第３手
順において、給湯制御弁をバランス開度ＸV0（％）に対
して、わずかに大きい開度に設定すれば、鋳造速度が一
定になったときにも、湯面レベルはわずかずつ上昇する
ようにできる。その後、湯面レベルがＬr （ｍｍ）に達
したときに湯面レベル一定制御に移行するようにすれ
ば、前記と同様にバンプレス移行ができるIn order to cope with such a case, if the opening of the hot water supply control valve is set slightly larger than the balance opening X V0 (%) in the third procedure, the casting speed becomes constant. Sometimes, the level can be raised slightly. Thereafter, when the level shifts to the level control when the level reaches L r (mm), the bumpless transition can be performed in the same manner as described above.
【００４２】[0042]
【実施例】図４は本発明の制御方法を適用した結果を示
すタイムチャートである。適用試験は鋼の中厚高速連続
鋳造機を用い、鋳型の断面積は９０ｍｍ×１０００ｍｍ
であった。FIG. 4 is a time chart showing the result of applying the control method of the present invention. The application test uses a medium thick high-speed continuous casting machine, and the cross-sectional area of the mold is 90 mm x 1000 mm.
Met.
【００４３】実施時の制御パラメータを次のように設定
した。なお、湯面レベルは鋳型の上端を０ｍｍとし、下
方は負方向で記している。The control parameters at the time of implementation were set as follows. The level of the molten metal is 0 mm at the upper end of the mold, and the lower side is indicated in the negative direction.
【００４４】Ｘ1 ＝８％、Ｘ2 ＝４％、ＴX1＝４ｓ、Ｌ
1 ＝−１９０ｍｍ、Ｌ2 ＝−１７０ｍｍ、Ｌ3 ＝−７０
ｍｍ、ＬV0＝−６５ｍｍ、Ｌr ＝−５０ｍｍ、Ｔsrt ＝
３０ｓ、Ｔlng ＝４５ｓ、Ｋの初期値＝３ｍｍ／ｓ／％
開度、Ｖ0 ＝３３．３ｍｍ／ｓ（＝２ｍ／ｍｉｎ）。X 1 = 8%, X 2 = 4%, T X1 = 4s, L
1 = -190mm, L 2 = -170mm , L 3 = -70
mm, L V0 = −65 mm, L r = −50 mm, T srt =
30 s, T lng = 45 s, initial value of K = 3 mm / s /%
Opening, V 0 = 33.3 mm / s (= 2 m / min).
【００４５】タンディッシュに溶鋼を保持した後、給湯
制御弁の初期開度を、Ｘ1 ＝８％、ＴX1＝４ｓ、Ｘ2 ＝
４％で設定し、鋳型に注湯開始した。湯面レベルがＬ1
＝−１９０ｍｍに達した時点で湯面レベルの上昇速度計
算用のデータＬ1 、ｔ1 を採取、記憶した。After holding the molten steel in the tundish, the initial opening of the hot water supply control valve was set to X 1 = 8%, T X1 = 4 s, and X 2 =
It was set at 4% and pouring into the mold was started. The bath level is L 1
When the temperature reached -190 mm, data L 1 and t 1 for calculating the rising speed of the molten metal level were collected and stored.
【００４６】Ｌ2 ＝−１７０ｍｍに達した時点で、推定
保持時間を求めると、Ｔhold＝２５ｓであった。これは
最短保持時間Ｔsrt ＝３０ｓより短いため、開度Ｘ
3 を、前記の(3) 、(4) 式により求め、Ｘ3 ＝２．５％
を算出して給湯制御弁開度を変更した。When L 2 = −170 mm was reached, the estimated holding time was determined to be T hold = 25 s. Since this is shorter than the shortest holding time T srt = 30 s, the opening X
3 is obtained by the above formulas (3) and (4), and X 3 = 2.5%
And the opening degree of the hot water supply control valve was changed.
【００４７】湯面レベルは更に上昇し、Ｌ3 ＝−７０ｍ
ｍに到達した時点で、予定のピンチロール引抜き速度と
湯面レベル上昇速度が等しくなるバランス開度ＸV0を
(7) 〜(9) 式により求め、ＸV0＝１１．１％を得て給湯
制御弁開度を変更した給湯開始から湯面レベルがＬ3 ＝
−７０ｍｍに達するまでの時間は約３０ｓであり、適正
保持時間の範囲内であった。The level of the molten metal surface further rises, and L 3 = −70 m
m, the balance opening degree X V0 at which the scheduled pinch roll withdrawal speed becomes equal to the molten metal level rise speed
From the equations (7) to (9), X V0 = 11.1% was obtained, and the hot water level was changed from the hot water supply start when the hot water supply control valve opening was changed to L 3 =
The time to reach -70 mm was about 30 s, which was within the range of the proper holding time.
【００４８】湯面レベルがＬV0＝−６５ｍｍに達する
と、鋳造速度を３３．３ｍｍ／ｓでダミーバーの引き抜
きを開始した。引抜き速度が一定になったとき、給湯流
量と引抜き速度がほぼバランスしており、湯面レベルは
−５５ｍｍでほぼ一定となった。引抜き開始後約４ｓ
（経過時間３４ｓ）で湯面レベル一定制御に移行した。
このとき、給湯制御弁がわずかに開→閉→開の動作をし
たが、数秒後には湯面レベル一定制御が安定した。When the molten metal level reached L V0 = −65 mm, the dummy bar was pulled out at a casting speed of 33.3 mm / s. When the drawing speed became constant, the hot water supply flow rate and the drawing speed were almost balanced, and the level of the molten metal became almost constant at -55 mm. Approximately 4s after the start of drawing
At (elapsed time 34 s), the control was shifted to the constant level control.
At this time, the hot water supply control valve slightly opened → closed → opened, but after a few seconds, the constant level control of the molten metal level became stable.
【００４９】従来例として、前記特開平５−３２９６０
５号公報に開示された制御方法を実施した。すなわち、
給湯開始から引抜き開始までの間、湯面レベル上昇速度
が予定引抜き速度と同じになるように湯面レベル上昇速
度制御を行い、引抜き開始後から定常鋳造時の目標湯面
レベルになるまでの間は、予め設定した一定速度で湯面
レベル上昇速度制御を行い、定常湯面レベルに達した時
に湯面レベル一定制御に移行する方法である。引抜き開
始後の「一定速度」として引抜き速度と同じ速度パラメ
ータを用いた。As a conventional example, see Japanese Patent Application Laid-Open No. 5-32960.
The control method disclosed in Japanese Patent Publication No. 5 was implemented. That is,
From the start of hot water supply to the start of drawing, the level control is performed so that the level rise rate is the same as the planned drawing rate.From the start of drawing until the target level is reached during steady casting Is a method in which the level control is performed at a preset constant speed, and when the steady level is reached, the control shifts to the level control. The same speed parameter as the drawing speed was used as the “constant speed” after the start of drawing.
【００５０】図５は上記従来例の制御による湯面レベル
変化を示すタイムチャートである。同図に示すように、
給湯開始からピンチロール起動までの間、過剰に給湯制
御弁の修正動作を行っており、湯面レベルの変動がきわ
めて大きく、かつその変動平均値を見ても、時間的に上
昇してゆく目標湯面レベルには追随できなかった。定常
湯面レベルに達してから、湯面レベル一定制御に移行し
たが、しばらくの間、湯面レベル変動が残った。FIG. 5 is a time chart showing a change in the level of the molten metal by the control of the conventional example. As shown in the figure,
The correction operation of the hot water supply control valve is performed excessively from the start of hot water supply to the start of the pinch roll, and the level of the level of the hot water level is extremely large. I couldn't keep up with the surface level. After reaching the steady level, the control was shifted to the constant level control, but the level fluctuation remained for a while.
【００５１】[0051]
【発明の効果】本発明により連続鋳造の鋳造開始からピ
ンチロール引抜き開始までの保持時間を所定値に管理
し、さらに湯面レベル一定制御に円滑に移行することが
できるので、鋳造開始時のブレークアウトの防止、鋳造
先端部の歩留、品質の向上などの効果が大きい。According to the present invention, the holding time from the start of continuous casting to the start of pinch roll drawing can be controlled to a predetermined value, and the control can be smoothly shifted to the level control of the molten metal level. It has great effects such as prevention of casting out, yield of the casting tip, and improvement of quality.
【図１】本発明の制御方法を実施するための装置の構成
図である。FIG. 1 is a configuration diagram of an apparatus for implementing a control method of the present invention.
【図２】本発明の制御方法による鋳造速度、給湯制御弁
開度および湯面レベルの変化を示すタイムチャートであ
る。FIG. 2 is a time chart showing changes in casting speed, opening degree of hot water supply control valve and level of molten metal according to the control method of the present invention.
【図３】本発明の制御方法の手順を示すフローチャート
である。FIG. 3 is a flowchart showing a procedure of a control method of the present invention.
【図４】本発明の制御方法を適用した結果を示すタイム
チャートである。FIG. 4 is a time chart showing the result of applying the control method of the present invention.
【図５】従来方法の制御による湯面レベル変化を示すタ
イムチャートである。FIG. 5 is a time chart showing a change in the level of the molten metal by the control of the conventional method.
１： タンディッシュ ２： 溶湯 ３： 給湯制御弁 ４： 浸漬ノズル ５： 鋳型 ６： ダミーバー ７： 湯面レベル計 ８： 湯面レベル制御装置 ９： ピンチロール １０： ピンチロール制御装置 1: Tundish 2: Molten metal 3: Hot water supply control valve 4: Immersion nozzle 5: Mold 6: Dummy bar 7: Level gauge 8: Level controller 9: Pinch roll 10: Pinch roll controller
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平８−294754（ＪＰ，Ａ) 特開 平９−122863（ＪＰ，Ａ) 特開 平１−170568（ＪＰ，Ａ) 特開 平５−329605（ＪＰ，Ａ) 特開 平８−294762（ＪＰ，Ａ) 特開 昭62−270264（ＪＰ，Ａ) 特開 平７−328775（ＪＰ，Ａ) 特開 昭62−179859（ＪＰ，Ａ) 特公 平２−51699（ＪＰ，Ｂ２) (58)調査した分野(Int.Cl.7，ＤＢ名) B22D 11/18 B22D 11/16 104 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-294754 (JP, A) JP-A-9-122863 (JP, A) JP-A-1-170568 (JP, A) JP-A-5-294 329605 (JP, A) JP-A-8-294762 (JP, A) JP-A-62-270264 (JP, A) JP-A-7-328775 (JP, A) JP-A-62-179859 (JP, A) Japanese Patent Publication No. 2-51699 (JP, B2) (58) Field surveyed (Int. Cl. 7 , DB name) B22D 11/18 B22D 11/16 104
Claims (1)
順の操作を行うことを特徴とする連続鋳造の湯面レベル
制御方法。 (1) タンディッシュから鋳型への給湯制御弁を所定の開
度に設定し、給湯する。 (2) 鋳型内の湯面が所定のレベルに達したとき、所定の
時間、湯面レベルを計測し、湯面レベルの上昇速度を求
める。この時の湯面レベルの上昇速度と、湯面レベルと
から、給湯開始から引抜き開始時の所定湯面レベルに至
るまでの保持時間を推定する。前記推定保持時間が目標
保持時間管理値の上限を超えるときは上限との時間差を
なくすように、下限未満のときは下限との時間差をなく
すように前記給湯制御弁の開度を修正する。 (3) 湯面が前記(2) の所定レベルよりさらに上位の所定
レベルに達したとき、湯面レベルの上昇速度が起動時の
ピンチロールの引抜き速度と同じになるように前記給湯
制御弁の開度を変更する。 (4) 湯面が前記(3) の所定レベルよりさらに上位の所定
レベルに達したとき、鋳片の引き抜きを開始する。1. A method for controlling the level of a molten metal level in continuous casting, wherein the following procedure is performed at the start of casting by a continuous casting machine. (1) The hot water supply control valve from the tundish to the mold is set to a predetermined opening degree to supply hot water. (2) When the level of the molten metal in the mold reaches a predetermined level, the level of the molten metal is measured for a predetermined time, and the rate of rise of the level of the molten metal is determined. From the rising speed of the molten metal level at this time and the molten metal level, the holding time from the start of hot water supply to the predetermined molten metal level at the start of drawing is estimated. When the estimated holding time exceeds the upper limit of the target holding time management value, the opening degree of the hot water supply control valve is corrected so as to eliminate the time difference from the upper limit, and when the estimated holding time is less than the lower limit, to eliminate the time difference from the lower limit. (3) When the level of the molten metal reaches a predetermined level higher than the predetermined level of (2), the rate of rise of the level of the molten metal is set to be the same as the pulling-out speed of the pinch roll at the time of startup. Change the opening. (4) When the molten metal surface reaches a predetermined level higher than the predetermined level in (3), the drawing of the slab is started.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30875798A JP3298523B2 (en) | 1998-10-29 | 1998-10-29 | Metal surface level control method for continuous casting |
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|---|---|---|---|
| JP30875798A JP3298523B2 (en) | 1998-10-29 | 1998-10-29 | Metal surface level control method for continuous casting |
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| Publication Number | Publication Date |
|---|---|
| JP2000135550A JP2000135550A (en) | 2000-05-16 |
| JP3298523B2 true JP3298523B2 (en) | 2002-07-02 |
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| Application Number | Title | Priority Date | Filing Date |
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| JP30875798A Expired - Fee Related JP3298523B2 (en) | 1998-10-29 | 1998-10-29 | Metal surface level control method for continuous casting |
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| JP (1) | JP3298523B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20210078869A (en) * | 2019-12-19 | 2021-06-29 | 현대제철 주식회사 | Method and apparatus for up flow of molten steel by inclusion |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP4082217B2 (en) | 2001-04-09 | 2008-04-30 | 住友電気工業株式会社 | Magnesium alloy material and method for producing the same |
| JP4661857B2 (en) * | 2001-04-09 | 2011-03-30 | 住友電気工業株式会社 | Magnesium alloy material and method for producing the same |
| EP2025432B2 (en) * | 2007-07-27 | 2017-08-30 | Concast Ag | Method for creating steel long products through strand casting and rolling |
| CN105665675A (en) * | 2016-04-07 | 2016-06-15 | 江苏永钢集团有限公司 | Automatic control and alarming system of molten steel liquid level in crystallizer of continuous casting machine |
| CN112371938B (en) * | 2020-10-09 | 2021-12-24 | 中冶南方连铸技术工程有限责任公司 | Method, device and equipment for optimizing action cycle of blank moving vehicle and storage medium |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6254562A (en) * | 1985-09-02 | 1987-03-10 | Nippon Steel Corp | Method for controlling casting in initial period of continuous casting |
| JPS62179859A (en) * | 1986-02-03 | 1987-08-07 | Nippon Kokan Kk <Nkk> | Auto-start controlling method for continuous casting machine |
| JPS62270264A (en) * | 1986-05-20 | 1987-11-24 | Nippon Steel Corp | Control method at casting initial stage for continuous casting |
| JPH01170568A (en) * | 1987-12-25 | 1989-07-05 | Fuji Electric Co Ltd | Method for controlling molten metal surface level |
| JP3102140B2 (en) * | 1992-05-29 | 2000-10-23 | 川崎製鉄株式会社 | Automatic casting start method for continuous casting |
| JP2510130B2 (en) * | 1994-06-08 | 1996-06-26 | 國洋電機工業株式会社 | Secondary cable deterioration determination device for resistance welding machine |
| JP3214333B2 (en) * | 1995-03-01 | 2001-10-02 | 日本鋼管株式会社 | Automatic start control method and apparatus for continuous casting |
| JP3218953B2 (en) * | 1995-02-28 | 2001-10-15 | 日本鋼管株式会社 | Continuous casting operation control method |
| JPH09122863A (en) * | 1995-10-27 | 1997-05-13 | Nippon Steel Corp | Method for controlling molten metal surface level in continuous caster for thin cast slab |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20210078869A (en) * | 2019-12-19 | 2021-06-29 | 현대제철 주식회사 | Method and apparatus for up flow of molten steel by inclusion |
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| JP2000135550A (en) | 2000-05-16 |
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