JP6428418B2

JP6428418B2 - Drift detection method and drift control method in continuous casting mold, molten metal level fluctuation detection method and molten metal level fluctuation control method, drift current detection device, molten metal level fluctuation detection device, and program

Info

Publication number: JP6428418B2
Application number: JP2015057605A
Authority: JP
Inventors: 平本　祐二; 祐二平本; 中川　淳一; 淳一中川; 福永　新一; 新一福永
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 2015-03-20
Filing date: 2015-03-20
Publication date: 2018-11-28
Anticipated expiration: 2035-03-20
Also published as: JP2016175106A

Description

本発明は、連続鋳造鋳型（モールド）内の偏流検知方法及び偏流制御方法、湯面変動検知方法及び湯面変動制御方法、偏流検知装置及び湯面変動検知装置、並びにプログラムに関する。 The present invention relates to a drift detection method and drift control method in a continuous casting mold (mold), a molten metal surface fluctuation detection method and a molten metal surface fluctuation control method, a drift current detection device, a molten metal surface variation detection device , and a program.

連続鋳造操業において、鋳片品質の高位安定化及び鋳片品質の変動を把握する上で、連続鋳造鋳型内の偏流検知や湯面変動検知は極めて重要である。
まず、偏流や湯面変動といった現象の発生原因及び鋳片品質に与える影響について説明する。 In continuous casting operations, detection of drift in a continuous casting mold and detection of fluctuations in the molten metal surface are extremely important for stabilizing the slab quality and grasping fluctuations in the slab quality.
First, the cause of occurrence of phenomena such as drift and fluctuation of the molten metal surface and the influence on the slab quality will be described.

（偏流について）
例えばスラブの連続鋳造において、浸漬ノズルの左右の吐出孔から吐出した溶鋼流が鋳型短辺に衝突して上昇流と下降流を形成する。この左右の吐出流は、浸漬ノズル直胴部における流動のばらつきや直胴部内壁への介在物付着等によって左右に吐出される吐出流の強さにばらつきが生じ（以下、偏流ともいう）、鋳型短辺に衝突する流速に差異が生じる。この偏流が生じると、浸漬ノズルを挟んだ湯面の左右で流速に違いが生じ、溶鋼流速が速い側では湯面付近で表面に浮遊する溶融パウダーを巻き込んだり、鋳型短辺衝突後に生じる下降流流速が増大し、溶鋼中の非金属介在物をストランド深くまで侵入させたりして、鋳片内部品質を悪化させる。結果、製品工程でヘゲ疵やスリバー疵の増大を招き、より深く侵入した介在物はユーザでのプレス加工時等に介在物を起点とした割れの原因となる。 (About drift)
For example, in continuous casting of a slab, the molten steel flow discharged from the left and right discharge holes of the immersion nozzle collides with the mold short side to form an upward flow and a downward flow. This left and right discharge flow varies in the strength of the discharge flow discharged to the left and right due to variations in flow in the submerged nozzle straight body part and inclusions adhering to the inner wall of the straight body part (hereinafter also referred to as uneven flow), A difference occurs in the flow velocity that collides with the short side of the mold. When this uneven flow occurs, the flow velocity differs on the left and right sides of the molten metal sandwiching the immersion nozzle, and on the side where the molten steel flow velocity is fast, molten powder floating on the surface is entrained near the molten metal surface. The flow rate is increased, and the nonmetallic inclusions in the molten steel are infiltrated deep into the strand, thereby deteriorating the slab internal quality. As a result, there is an increase in the amount of lashes and sliver in the product process, and inclusions that penetrate more deeply cause cracks starting from the inclusions during press working by the user.

（湯面変動について）
連続鋳造における浸漬ノズル内壁に付着した主にＡ１₂０₃系介在物の剥離により溶鋼流の流動抵抗が変化し、吐出流が脈動することが従来から知られている。付着の進行による流動抵抗の漸増に対応して、スライディングノズル或いはストッパー等の流量制御系は開度を開いてきているため、介在物剥離直後の流動抵抗の急激な減少に対応できず、連続鋳造鋳型内に流入する溶鋼流量が一時的に増大し、溶鋼吐出流速が増大する。結果、湯面付近で表面に浮遊する溶融パウダーを巻き込んだり、鋳型短辺衝突後に生じる下降流流速が増大し、溶鋼中の非金属介在物をストランド深くまで侵入させたりして、鋳片内部品質を悪化させる。結果、製品工程でヘゲ疵やスリバー疵の増大を招き、より深く侵入した介在物はユーザでのプレス加工時等に介在物を起点とした割れの原因となる。 (About hot water fluctuation)
It has been conventionally known that the flow resistance of the molten steel flow changes due to the peeling of the A1 ₂ 0 ₃ inclusions adhering to the inner wall of the immersion nozzle in continuous casting, and the discharge flow pulsates. Corresponding to the gradual increase in flow resistance due to the progress of adhesion, the flow control system such as the sliding nozzle or stopper is opening, so it cannot cope with the rapid decrease in flow resistance immediately after inclusion peeling, and continuous casting. The flow rate of molten steel flowing into the mold temporarily increases, and the molten steel discharge flow rate increases. As a result, the molten powder floating on the surface near the surface of the molten metal is entrained, the flow velocity of the downflow generated after collision with the short side of the mold is increased, and the nonmetallic inclusions in the molten steel are infiltrated deep into the strand. Worsen. As a result, there is an increase in the amount of lashes and sliver in the product process, and inclusions that penetrate more deeply cause cracks starting from the inclusions during press working by the user.

例えば特許文献１には、鋳型壁の高さ方向に沿って等間隔に複数個の測温素子を埋設し、任意周期毎に各素子の点における温度の時間変化率値を演算し、該時間変化率の最大値を示す素子（ｎ）を検出し、該素子（ｎ）とその前後の素子（ｎ−１）、（ｎ＋１）の各時間変化率値を結ぶ二次曲線の最大値を示す位置を求め、該位置を湯面レベルとする技術が開示されている。 For example, in Patent Document 1, a plurality of temperature measuring elements are embedded at equal intervals along the height direction of the mold wall, and a time change rate value of temperature at each element point is calculated for each arbitrary period. The element (n) showing the maximum value of the change rate is detected, and the maximum value of the quadratic curve connecting the time change rate values of the element (n) and the preceding and following elements (n−1) and (n + 1) is shown. A technique for obtaining a position and setting the position to a hot water level is disclosed.

特許文献２には、鋳造方向に間隔をおいて鋳型の複数箇所に埋設した温度計測手段で鋳型温度を計測し、鋳型温度計測値に基づいて各計測点における鋳型内面での熱流束を伝熱逆問題手法を用いてそれぞれ推定する技術が開示されている。 In Patent Document 2, the mold temperature is measured by temperature measuring means embedded in a plurality of locations of the mold at intervals in the casting direction, and the heat flux on the inner surface of the mold at each measurement point is transferred based on the measured mold temperature. Techniques for estimating using inverse problem methods are disclosed.

特許文献３には、鋳型短辺側に向いた溶鋼の吐出孔を有する浸漬ノズルを鋳型中央に配して鋳造を行う連続鋳造に際し、前記浸漬ノズルを境とする左右両側の鋳型銅板の各長辺および短辺内にそれぞれ溶鋼表面から深さ方向に少なくとも２本以上、更に銅板表面から深さ方向に少なくとも２本以上の熱電対を埋設し、上記熱電対で検出される前記浸漬ノズルを境とする左右両側対称位置の熱電対から測定される温度差あるいはその温度差から求められる熱流束差とある一定値に対する偏差を求め、この偏差をもとに鋳型内溶鋼吐出流の偏流を検出する技術が開示されている。 In Patent Document 3, in continuous casting in which an immersion nozzle having a molten steel discharge hole facing the short side of the mold is placed in the center of the mold and casting is performed, each length of the left and right mold copper plates with the immersion nozzle as a boundary is described. At least two or more thermocouples are buried in the depth direction from the surface of the molten steel, and at least two or more thermocouples are buried in the depth direction from the surface of the molten steel in the sides and short sides, respectively, and the immersion nozzle detected by the thermocouple as a boundary. The temperature difference measured from the thermocouples at the left and right symmetrical positions and the heat flux difference obtained from the temperature difference and a deviation from a certain value are obtained, and the deviation of the molten steel discharge flow in the mold is detected based on this deviation. Technology is disclosed.

特許文献４には、鋳型両短辺にそれぞれ埋設した温度計または浸漬ノズルとその両側の鋳型両短辺との間に配設したレベル計により、鋳型両短辺近傍に生じる溶鋼湯面の隆起量を測定することによって鋳型内における溶鋼偏流を検知する技術が開示されている。 In Patent Document 4, the rise of the molten steel surface generated near the short sides of the mold is measured by a thermometer or an immersion nozzle embedded in both short sides of the mold and a level meter disposed between the short sides of the mold on both sides. A technique for detecting molten steel drift in a mold by measuring the amount is disclosed.

特許文献５には、鋳型銅板幅方向に複数の熱電対を配置して鋳型銅板温度を測定し、各測定温度の特定の周波数成分の変動量から鋳型内幅方向各位置の湯面変動量を推定する技術が開示されている。 In Patent Document 5, a plurality of thermocouples are arranged in the width direction of the mold copper plate, the temperature of the mold copper plate is measured, and the fluctuation amount of the molten metal surface at each position in the width direction of the mold is calculated from the fluctuation amount of a specific frequency component of each measurement temperature. An estimation technique is disclosed.

特開昭５３−２６２３０号公報JP-A-53-26230 特開２００１−２３９３５３号公報JP 2001-239353 A 特開平１−２６２０５０号公報JP-A-1-262050 特開平４−８４６５０号公報JP-A-4-84650 特開平１１−９０６００号公報JP-A-11-90600

しかしながら、特許文献１に代表される既存の手法は、鋳型の鋳造方向の温度が最大となる位置が湯面近傍にあり、湯面位置とある相関があるという経験則に基づくものである。このように経験則に基づく場合、湯面レベルの検出精度が低いものとなってしまう懸念がある。具体的には、鋳型に埋設された熱電対の温度変化率は溶鋼温度や、湯面変化速度によって左右され、溶鋼温度が高いほど温度変化率が大きくなり、また湯面変化速度が大きいと鋳型の温度上昇の時間遅れにより湯面位置の検出遅れが大きくなるという問題がある。また、特許文献１には、偏流検知に関する記述はなく、湯面変動検知に関しては、「溶鋼レベルの上昇或いは下降傾向を判別することが可能」との記述のみで、どの程度の湯面検知精度が得られるのかの具体的な記述はない。
特許文献２の手法は、熱流束を伝熱逆問題を用いて推定する方法であるが、熱流束と湯面レベル、湯面変動検知、偏流検知の関係についての記述はない。
特許文献３の手法は、熱電対を埋設した部位に溶鋼流が流れ、かつ壁面に沿って流動した場合には偏流検知が可能である。しかしながら、本発明者らの流動実験によると、溶鋼流は吐出孔から吐出した後、徐々に広がりながら鋳型短辺に向かって流れるため、長辺の凝固シェル壁面に溶鋼流が到達するには、一定の流動距離（幅）が必要であること、本発明者らの研究によれば、浸漬ノズル直胴部における流速分布の影響を受けて、吐出した流れが鋳型短辺にまっすぐ向かう流れとはならない場合が多く（長辺に流れが到達しない場合が多い）、長辺での温度差の左右での温度差あるいは熱流束差があったとしても、左右の偏流に起因するとは限らないため、偏流が過検知ぎみとなることが避けられない。また、鋳型短辺に埋設した熱電対の左右の温度差あるいは熱流束差から偏流を検知する場合、左右の吐出流が非対称な流れとなり、上述したように吐出した流れが短辺にまっすぐ向かう流れとはならない場合が多いために、左右対称の熱電対位置であっても、片側の熱電対位置のみ吐出流が強く衝突する場合がある。そのために、温度差あるいは熱流束差が偏流に起因したものとはならず、偏流が過検知ぎみとなることが避けられない。
特許文献４の手法は、短辺の溶鋼隆起の両短辺の差が１０ｍｍ以下となる制御を行うとしているが、熱電対の出力で１０ｍｍの差を検出しようとした場合、鋳型壁面高さ方向に数ｍｍでの非常に細かいピッチで熱電対を埋設する必要があり、熱電対取り付けや保守管理等、煩雑な手間が生じることは避けられず、実用性に乏しい。また、浸漬ノズルと両短辺の間に配設したレベル計で隆起を計測する場合、センサーの計測範囲の大きさにもよるが、鋳型壁面に近接しすぎると鋳型壁面の影響で正確な湯面の計測ができなくなるため、鋳型壁面からセンサーを一定距離以上離す必要がある。しかしながら、距離が離れると湯面の隆起は小さくなるため、正確な偏流検知精度が得られなくなる問題がある。
特許文献５の手法は、鋳型銅板幅方向に配置した複数の熱電対の特定周波数の変動量と、各位置の湯面変動量との間に相関関係があるとの経験則に基づくものであるが、湯面変動の中で湯面の上昇、下降が把握可能かは明示されていない。連続鋳造の操業においては、湯面変動量以外に湯面の急上昇や低下による品質悪化要因の検出も重要であり、特許文献５の手段では、十分な対応が困難である。 However, the existing method represented by Patent Document 1 is based on an empirical rule that the position where the temperature in the casting direction of the mold is maximum is in the vicinity of the molten metal surface and has a certain correlation with the molten metal surface position. Thus, when based on an empirical rule, there exists a possibility that the detection accuracy of a hot-water surface level may become low. Specifically, the temperature change rate of the thermocouple embedded in the mold depends on the molten steel temperature and the molten metal surface rate of change. The higher the molten steel temperature, the larger the rate of temperature change. There is a problem that the detection delay of the hot water surface position becomes large due to the time delay of the temperature rise. In addition, Patent Document 1 does not describe drift detection, and with regard to molten metal level fluctuation detection, only the description that “a rising or falling tendency of the molten steel level can be discriminated” is used. There is no specific description of whether or not
The method of Patent Document 2 is a method for estimating the heat flux using the inverse heat transfer problem, but there is no description about the relationship between the heat flux and the molten metal surface level, molten metal surface fluctuation detection, and drift detection.
The technique of Patent Document 3 can detect a drift when a molten steel flow flows in a portion where a thermocouple is embedded and flows along a wall surface. However, according to the flow experiment of the present inventors, the molten steel flow flows from the discharge hole toward the short side of the mold while gradually spreading, so that the molten steel flow reaches the long-side solidified shell wall surface, According to the study by the present inventors that a constant flow distance (width) is necessary, the flow that is discharged straight from the short side of the mold is affected by the flow velocity distribution in the straight body portion of the immersion nozzle. In many cases, the flow does not reach the long side, and even if there is a temperature difference or a heat flux difference between the left and right of the long side, it does not always result from the left and right drifts. It is inevitable that the drift will be overdetected. Also, when detecting drift from the left or right temperature difference or heat flux difference of the thermocouple embedded in the short side of the mold, the left and right discharge flows become asymmetrical, and the flow discharged as described above flows straight toward the short side. Therefore, even if the thermocouple position is symmetrical, the discharge flow may collide strongly only at the thermocouple position on one side. Therefore, the temperature difference or the heat flux difference is not caused by the drift, and the drift is unavoidably overdetected.
In the method of Patent Document 4, the difference between both short sides of the molten steel bulge on the short side is controlled to be 10 mm or less. However, when detecting the difference of 10 mm with the output of the thermocouple, In addition, it is necessary to embed thermocouples at a very fine pitch of several millimeters, and it is unavoidable that troublesome work such as thermocouple attachment and maintenance management is unavoidable, and the practicality is poor. In addition, when measuring the uplift with a level meter placed between the immersion nozzle and both short sides, depending on the size of the sensor measurement range, if it is too close to the mold wall surface, the mold wall surface will cause an accurate hot water. Since it becomes impossible to measure the surface, the sensor needs to be separated from the mold wall surface by a certain distance or more. However, when the distance is increased, the rise of the molten metal surface becomes small, and there is a problem that accurate drift detection accuracy cannot be obtained.
The method of Patent Document 5 is based on an empirical rule that there is a correlation between the fluctuation amount of the specific frequency of the plurality of thermocouples arranged in the width direction of the mold copper plate and the fluctuation amount of the molten metal surface at each position. However, it is not specified whether the rise and fall of the molten metal level can be grasped in the fluctuation of the molten metal level. In the operation of continuous casting, it is important to detect the factor of quality deterioration due to the rapid rise and fall of the molten metal surface in addition to the molten metal surface fluctuation amount, and it is difficult to sufficiently cope with the means of Patent Document 5.

本発明は上記のような点に鑑みてなされたものであり、湯面位置における熱移動の影響を捉えて湯面レベルを検出することにより湯面レベルの検出精度を高め、鋳型内の偏流の検知精度、湯面変動の検知精度向上を図り、鋳片品質の安定化を実現することを目的とする。 The present invention has been made in view of the above points, and by detecting the level of the molten metal level by detecting the influence of heat transfer at the level of the molten metal level, the accuracy of detection of the molten metal level is improved, and the drift in the mold is prevented. The aim is to improve the detection accuracy and detection accuracy of molten metal level fluctuations and to stabilize the quality of the slab.

上記課題を解決するための、本発明は以下のとおりである。
［１］連続鋳造鋳型内の偏流検知方法であって、
浸漬ノズルを挟んで対向する一対の鋳型辺それぞれの鋳造方向に配置、埋設された複数の温度検出手段の計測値を取得する取得ステップと、
前記取得ステップで取得した前記温度検出手段の計測値を用いて伝熱逆問題を解き、稼動面における熱流束の鋳造方向の成分値を計算する計算ステップと、
前記計算ステップで計算した稼動面における熱流束の鋳造方向の成分値に基づいて、湯面レベルを判定し、前記一対の鋳型辺の稼動面における湯面レベル差を求める湯面レベル差解析ステップとを有し、
前記湯面レベル差解析ステップでは、前記計算ステップで計算した稼動面における熱流束の鋳造方向と逆向きとなる湯面の法線方向の成分値が最大となる位置を湯面レベルと判定することを特徴とする連続鋳造鋳型内の偏流検知方法。
［２］［１］に記載の連続鋳造鋳型内の偏流検知方法により求めた湯面レベル差が所定の値を超えたとき、鋳造速度を減少させることを特徴とする連続鋳造鋳型内の偏流制御方法。
［３］湯面レベル差が１０ｍｍを超えたとき、鋳造速度を１０％以上減少させることを特徴とする［２］に記載の連続鋳造鋳型内の偏流制御方法。
［４］連続鋳造鋳型内の湯面変動検知方法であって、
前記連続鋳造鋳型の鋳造方向に配置、埋設された複数の温度検出手段の計測値を取得する取得ステップと、
前記取得ステップで取得した前記温度検出手段の計測値を用いて伝熱逆問題を解き、稼動面における熱流束の鋳造方向の成分値を計算する計算ステップと、
前記計算ステップで計算した稼動面における熱流束の鋳造方向の成分値に基づいて、湯面レベルを判定し、湯面変動速度を求める湯面変動解析ステップとを有し、
前記湯面変動解析ステップでは、前記計算ステップで計算した稼動面における熱流束の鋳造方向と逆向きとなる湯面の法線方向の成分値が最大となる位置を湯面レベルと判定することを特徴とする連続鋳造鋳型内の湯面変動検知方法。
［５］浸漬ノズルの中心から左右鋳型短辺までの鋳型長辺幅方向距離をそれぞれＷ／２とした場合に、鋳型長辺において、前記浸漬ノズルの中心から３Ｗ／８以内に前記温度検出手段を配置、埋設することを特徴とする［４］に記載の連続鋳造鋳型内の湯面変動検知方法。
［６］［４］又は［５］に記載の連続鋳造鋳型内の湯面変動検知方法により求めた湯面変動速度が所定の値以上となったとき、鋳造速度を減少させることを特徴とする連続鋳造鋳型内の湯面変動制御方法。
［７］湯面変動速度が１０ｍｍ／３０秒以上となったとき、鋳造速度を１０％以上減少させることを特徴とする［６］に記載の連続鋳造鋳型内の湯面変動制御方法。
［８］連続鋳造鋳型内の偏流検知装置であって、
浸漬ノズルを挟んで対向する一対の鋳型辺それぞれの鋳造方向に配置、埋設された複数の温度検出手段の計測値を入力する入力手段と、
前記入力手段で入力した前記温度検出手段の計測値を用いて伝熱逆問題を解き、稼動面における熱流束の鋳造方向の成分値を計算する計算手段と、
前記計算手段で計算した稼動面における熱流束の鋳造方向の成分値に基づいて、湯面レベルを判定し、前記一対の鋳型辺の稼動面における湯面レベル差を求める湯面レベル差解析手段とを備え、
前記湯面レベル差解析手段は、前記計算手段で計算した稼動面における熱流束の鋳造方向と逆向きとなる湯面の法線方向の成分値が最大となる位置を湯面レベルと判定することを特徴とする連続鋳造鋳型内の偏流検知装置。
［９］連続鋳造鋳型内の湯面変動検知装置であって、
前記連続鋳造鋳型の鋳造方向に配置、埋設された複数の温度検出手段の計測値を入力する入力手段と、
前記入力手段で入力した前記温度検出手段の計測値を用いて伝熱逆問題を解き、稼動面における熱流束の鋳造方向の成分値を計算する計算手段と、
前記計算手段で計算した稼動面における熱流束の鋳造方向の成分値に基づいて、湯面レベルを判定し、湯面変動速度を求める湯面変動解析手段とを備え、
前記湯面変動解析手段は、前記計算手段で計算した稼動面における熱流束の鋳造方向と逆向きとなる湯面の法線方向の成分値が最大となる位置を湯面レベルと判定することを特徴とする連続鋳造鋳型内の湯面変動検知装置。
［１０］連続鋳造鋳型内の偏流検知を行うためのプログラムであって、
浸漬ノズルを挟んで対向する一対の鋳型辺それぞれの鋳造方向に配置、埋設された複数の温度検出手段の計測値を入力する入力処理と、
前記入力した前記温度検出手段の計測値を用いて伝熱逆問題を解き、稼動面における熱流束の鋳造方向の成分値を計算する計算処理と、
前記計算した稼動面における熱流束の鋳造方向の成分値に基づいて、湯面レベルを判定し、前記一対の鋳型辺の稼動面における湯面レベル差を求める湯面レベル差解析処理とをコンピュータに実行させ、
前記湯面レベル差解析処理では、前記計算処理で計算した稼動面における熱流束の鋳造方向と逆向きとなる湯面の法線方向の成分値が最大となる位置を湯面レベルと判定することを特徴とするプログラム。
［１１］連続鋳造鋳型内の湯面変動検知を行うためのプログラムであって、
前記連続鋳造鋳型の鋳造方向に配置、埋設された複数の温度検出手段の計測値を入力する入力処理と、
前記入力した前記温度検出手段の計測値を用いて伝熱逆問題を解き、稼動面における熱流束の鋳造方向の成分値を計算する計算処理と、
前記計算した稼動面における熱流束の鋳造方向の成分値に基づいて、湯面レベルを判定し、湯面変動速度を求める湯面変動解析処理とをコンピュータに実行させ、
前記湯面変動解析処理では、前記計算処理で計算した稼動面における熱流束の鋳造方向と逆向きとなる湯面の法線方向の成分値が最大となる位置を湯面レベルと判定することを特徴とするプログラム。 In order to solve the above problems, the present invention is as follows.
[1] A method for detecting drift in a continuous casting mold,
An acquisition step of acquiring measurement values of a plurality of temperature detection means arranged and embedded in each casting direction of a pair of mold sides facing each other across the immersion nozzle;
A calculation step for solving the inverse heat transfer problem using the measurement value of the temperature detection means acquired in the acquisition step and calculating a component value in the casting direction of the heat flux on the working surface;
Based on the component value in the casting direction of the heat flux on the operating surface calculated in the calculating step, the molten metal surface level is determined, and a molten metal surface level difference analyzing step for obtaining a molten metal surface level difference on the operating surface of the pair of mold sides; I have a,
In the molten metal surface level difference analyzing step, the position where the component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated in the calculating step is determined as the molten metal surface level. A method for detecting drift in a continuous casting mold.
[ 2 ] The drift control in the continuous casting mold, wherein the casting speed is reduced when the difference in the molten metal surface level obtained by the drift detection method in the continuous casting mold according to [1] exceeds a predetermined value. Method.
[ 3 ] The drift control method in the continuous casting mold according to [2] , wherein the casting speed is reduced by 10% or more when the difference in molten metal level exceeds 10 mm.
[ 4 ] A method for detecting a change in molten metal level in a continuous casting mold,
An acquisition step of acquiring measurement values of a plurality of temperature detection means arranged and embedded in the casting direction of the continuous casting mold,
A calculation step for solving the inverse heat transfer problem using the measurement value of the temperature detection means acquired in the acquisition step and calculating a component value in the casting direction of the heat flux on the working surface;
The calculation based on the component values of the casting direction of the heat flux in operation plane calculated in step, to determine the melt-surface levels, possess a melt surface variation analysis step of obtaining a melt surface variation rate,
In the molten metal surface fluctuation analyzing step, the position where the component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated in the calculating step is determined as the molten metal surface level. A method for detecting fluctuations in the molten metal level in a continuous casting mold.
[ 5 ] When the distance in the mold long side width direction from the center of the immersion nozzle to the short side of the left and right molds is W / 2, respectively, the temperature detecting means is within 3 W / 8 from the center of the immersion nozzle in the mold long side. The method for detecting fluctuations in the molten metal level in the continuous casting mold as described in [4] , wherein :
[ 6 ] The casting speed is reduced when the molten metal surface fluctuation speed obtained by the method for detecting fluctuation of the molten metal surface in the continuous casting mold described in [4] or [5] exceeds a predetermined value. A method for controlling the fluctuation of the molten metal surface in a continuous casting mold.
[ 7 ] The method for controlling the fluctuation of the molten metal surface in the continuous casting mold according to [6] , wherein the casting speed is reduced by 10% or more when the molten metal surface fluctuation speed becomes 10 mm / 30 seconds or more.
[ 8 ] A drift detection device in a continuous casting mold,
An input means for inputting measurement values of a plurality of temperature detection means arranged and embedded in each casting direction of a pair of mold sides facing each other across the immersion nozzle;
A calculation means for solving the inverse heat transfer problem using the measured value of the temperature detection means input by the input means, and calculating a component value in the casting direction of the heat flux on the working surface;
Based on the component value in the casting direction of the heat flux on the operating surface calculated by the calculating means, the molten metal surface level is determined, and the molten metal surface level difference analyzing means for obtaining the molten metal surface level difference on the operating surface of the pair of mold sides; equipped with a,
The molten metal level difference analyzing means determines the position where the component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated by the calculating means is the molten metal surface level. A drift detection device in a continuous casting mold characterized by the above.
[ 9 ] A hot water level fluctuation detecting device in a continuous casting mold,
Input means for inputting measurement values of a plurality of temperature detection means arranged and embedded in the casting direction of the continuous casting mold,
A calculation means for solving the inverse heat transfer problem using the measured value of the temperature detection means input by the input means, and calculating a component value in the casting direction of the heat flux on the working surface;
Based on the component value in the casting direction of the heat flux on the working surface calculated by the calculating means, the molten metal surface level is determined, and the molten metal surface fluctuation analyzing means for obtaining the molten metal surface fluctuation speed is provided .
The molten metal surface fluctuation analyzing means determines that the position at which the component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated by the calculating device is the maximum is the molten metal surface level. An apparatus for detecting fluctuations in the molten metal level in a continuous casting mold.
[ 10 ] A program for detecting drift in a continuous casting mold,
An input process for inputting the measurement values of a plurality of temperature detection means arranged and embedded in the casting direction of each of a pair of mold sides facing each other across the immersion nozzle,
A calculation process for solving a heat transfer inverse problem using the input measurement value of the temperature detection means and calculating a component value in the casting direction of the heat flux on the working surface;
Based on the component value in the casting direction of the heat flux on the calculated working surface, the molten metal level level is determined, and a molten metal level difference analysis process for obtaining a molten metal level difference on the working surface of the pair of mold sides is performed on a computer. to be executed,
In the molten metal surface level difference analysis process, the position where the component value in the normal direction of the molten metal surface that is opposite to the casting direction of the heat flux on the operating surface calculated in the calculation process is determined as the molten metal surface level. A program characterized by
[ 11 ] A program for detecting fluctuations in the molten metal surface in a continuous casting mold,
An input process for inputting measurement values of a plurality of temperature detection means arranged and embedded in the casting direction of the continuous casting mold,
A calculation process for solving a heat transfer inverse problem using the input measurement value of the temperature detection means and calculating a component value in the casting direction of the heat flux on the working surface;
Based on the component value in the casting direction of the heat flux on the calculated operating surface, the molten metal surface level is determined, and the molten metal surface fluctuation analyzing process for obtaining the molten metal surface fluctuation speed is executed by a computer ,
In the molten metal surface fluctuation analysis process, the position where the component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated in the calculation process is determined as the molten metal surface level. A featured program.

本発明によれば、湯面位置における熱移動の影響を捉えて湯面レベルを検出することにより湯面レベルの検出精度を高め、鋳型内の偏流の検知精度、湯面変動の検知精度向上を図り、鋳片品質の安定化を実現することができる。 According to the present invention, the detection accuracy of the molten metal surface level is improved by detecting the level of the molten metal surface by detecting the influence of the heat transfer at the molten metal surface position, and the detection accuracy of the drift in the mold and the detection accuracy of the molten metal surface level are improved. And stable slab quality can be achieved.

第１の実施形態における連続鋳造鋳型の概要を模式的に示す図である。It is a figure which shows typically the outline | summary of the continuous casting mold in 1st Embodiment. 第１の実施形態における熱電対の配置を示す図である。It is a figure which shows arrangement | positioning of the thermocouple in 1st Embodiment. 第１の実施形態における連続鋳造鋳型内の偏流検知の概要を説明するための図である。It is a figure for demonstrating the outline | summary of the drift detection in the continuous casting mold in 1st Embodiment. 第１の実施形態に係る連続鋳造鋳型内の偏流制御装置の機能構成を示す図である。It is a figure which shows the function structure of the drift control apparatus in the continuous casting mold which concerns on 1st Embodiment. 伝熱逆問題の座標系を示す図である。It is a figure which shows the coordinate system of a heat transfer inverse problem. 湯面レベルの検出の概要を説明するための図である。It is a figure for demonstrating the outline | summary of the detection of a hot-water surface level. 湯面レベルを実測するための装置構成例を示す図である。It is a figure which shows the example of an apparatus structure for measuring a hot_water | molten_metal surface level. 本発明の手法で検出した湯面レベルと、既存の手法で検出した湯面レベルと、実測の湯面レベルとを示す特性図である。It is a characteristic view which shows the hot-water surface level detected with the method of this invention, the hot-water surface level detected with the existing method, and the measured hot-water surface level. 第１の実施形態において制御部が実行する制御処理を示すフローチャートである。It is a flowchart which shows the control processing which a control part performs in 1st Embodiment. 第１の実施形態において鋳造速度を減少させた場合に制御部が実行する制御処理を示すフローチャートである。It is a flowchart which shows the control processing which a control part performs when the casting speed is reduced in 1st Embodiment. 第２の実施形態における連続鋳造鋳型の概要を模式的に示す図である。It is a figure which shows typically the outline | summary of the continuous casting mold in 2nd Embodiment. 第２の実施形態における熱電対の配置を示す図である。It is a figure which shows arrangement | positioning of the thermocouple in 2nd Embodiment. 第２の実施形態における連続鋳造鋳型内の湯面変動検知の概要を説明するための図である。It is a figure for demonstrating the outline | summary of the hot_water | molten_metal surface fluctuation | variation detection in the continuous casting mold in 2nd Embodiment. 第２の実施形態に係る連続鋳造鋳型内の湯面変動制御装置の機能構成を示す図である。It is a figure which shows the function structure of the hot_water | molten_metal surface fluctuation | variation control apparatus in the continuous casting mold which concerns on 2nd Embodiment. 第２の実施形態において制御部が実行する制御処理を示すフローチャートである。It is a flowchart which shows the control processing which a control part performs in 2nd Embodiment. 第２の実施形態において鋳造速度を減少させた場合に制御部が実行する制御処理を示すフローチャートである。It is a flowchart which shows the control processing which a control part performs when the casting speed is reduced in 2nd Embodiment.

以下、添付図面を参照して、本発明の好適な実施形態について説明する。
［第１の実施形態］
第１の実施形態として、連続鋳造鋳型（以下、単に鋳型と呼ぶ）内の偏流を検知し、必要に応じて偏流を抑制するように鋳造速度を制御する例を説明する。
図１に、鋳型１の概要を模式的に示す。鋳型１は、互いに対向する一対の鋳型短辺２ａ、２ｂと、互いに対向する一対の鋳型長辺３ａ、３ｂとにより構成される。鋳型１の内面を稼動面、外面を水冷面と呼ぶ。即ち、鋳型１の各面のうち、溶湯に接する面が稼動面である（ただし、潤滑パウダーを用いる場合は該潤滑パウダーを通して溶湯に接する）。
鋳型１の中央には浸漬ノズル４が配置されており、浸漬ノズル４の左右の吐出孔４ａ、４ｂから左右の鋳型短辺２ａ、２ｂへ向かって溶鋼が吐出される。符号５は、湯面を示す。なお、図１は左右一対の吐出孔４ａ、４ｂを有する例を示すが、吐出孔は左右複数対あってもよい。 Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
[First Embodiment]
As a first embodiment, an example will be described in which a drift in a continuous casting mold (hereinafter simply referred to as a mold) is detected and the casting speed is controlled so as to suppress the drift as necessary.
In FIG. 1, the outline | summary of the casting_mold | template 1 is shown typically. The mold 1 includes a pair of mold short sides 2a and 2b facing each other and a pair of mold long sides 3a and 3b facing each other. The inner surface of the mold 1 is called the working surface, and the outer surface is called the water-cooled surface. That is, of the surfaces of the mold 1, the surface that contacts the molten metal is the working surface (however, when lubricating powder is used, it contacts the molten metal through the lubricating powder).
An immersion nozzle 4 is disposed at the center of the mold 1, and molten steel is discharged from the left and right discharge holes 4 a, 4 b of the immersion nozzle 4 toward the left and right mold short sides 2 a, 2 b. Reference numeral 5 indicates a hot water surface. Although FIG. 1 shows an example having a pair of left and right discharge holes 4a and 4b, a plurality of right and left discharge holes may be provided.

一対の鋳型短辺２ａ、２ｂには、鋳造方向に複数の熱電対６が配置、埋設される。図２に、鋳型短辺２ａ（２ｂ）の熱電対６の配置例を示す。
本実施形態では、図３に示すように、偏流の指標として、一方の鋳型短辺２ａの稼動面における湯面レベルと、他方の鋳型短辺２ｂの稼動面における湯面レベルとの差（以下、湯面レベル差と呼ぶ）ΔＹを求める。 A plurality of thermocouples 6 are arranged and embedded in the pair of mold short sides 2a and 2b in the casting direction. In FIG. 2, the example of arrangement | positioning of the thermocouple 6 of the casting_mold | template short side 2a (2b) is shown.
In the present embodiment, as shown in FIG. 3, as an index of drift, a difference between a molten metal level on the operating surface of one mold short side 2a and a molten metal surface level on the operating surface of the other mold short side 2b (hereinafter referred to as the mold short side 2b). ΔY) (referred to as a hot water level difference).

図４に、連続鋳造鋳型内の偏流制御装置１００の機能構成を示す。なお、本実施形態では、偏流制御装置１００が本発明を適用した連続鋳造鋳型内の偏流検知装置としても機能する。
１０１は入力部であり、鋳型短辺２ａ、２ｂの鋳造方向に配置、埋設された複数の熱電対６の計測値を入力する。
１０２は計算部であり、詳細は後述するが、入力部１０１で入力した熱電対６の計測値を用いて伝熱逆問題を解き、稼動面における熱流束の鋳造方向のベクトル成分値、換言すれば稼動面における熱流束の湯面に垂直な方向のベクトル成分値を計算する。
１０３は湯面レベル差解析部であり、計算部１０２で計算した稼動面における熱流束の鋳造方向と逆向きとなる湯面の法線方向のベクトル成分値が最大となる位置を湯面レベルと判定し、鋳型短辺２ａ、２ｂの稼動面における湯面レベル差ΔＹを求める。
１０４は制御部であり、詳細は後述するが、湯面レベル差解析部１０３で求めた湯面レベル差ΔＹに基づいて、偏流を抑制するように鋳造速度を制御する。
入力部１０１、計算部１０２、湯面レベル差解析部１０３、及び制御部１０４は、例えば一定周期で、熱電対６の計測値の入力、ベクトル成分値の計算、湯面レベル差ΔＹの計算、及び湯面レベル差ΔＹに応じた制御を実行する。 FIG. 4 shows a functional configuration of the drift control device 100 in the continuous casting mold. In the present embodiment, the drift control device 100 also functions as a drift detection device in a continuous casting mold to which the present invention is applied.
Reference numeral 101 denotes an input unit for inputting measured values of a plurality of thermocouples 6 arranged and embedded in the casting direction of the mold short sides 2a and 2b.
Reference numeral 102 denotes a calculation unit, which will be described in detail later, but solves the inverse heat transfer problem using the measured value of the thermocouple 6 input by the input unit 101, in other words, the vector component value in the casting direction of the heat flux on the operating surface, in other words For example, the vector component value in the direction perpendicular to the molten metal surface of the heat flux on the operating surface is calculated.
103 is a molten metal surface level difference analysis unit, and the position where the vector component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated by the calculating unit 102 is the maximum is the molten metal surface level. Determination is made to obtain a molten metal level difference ΔY on the working surface of the mold short sides 2a, 2b.
Reference numeral 104 denotes a control unit, which will be described in detail later, and controls the casting speed so as to suppress the drift based on the molten metal level difference ΔY obtained by the molten metal level difference analyzing unit 103.
The input unit 101, the calculation unit 102, the molten metal level difference analysis unit 103, and the control unit 104 are, for example, at regular intervals, input of measurement values of the thermocouple 6, calculation of vector component values, calculation of the molten metal level difference ΔY, And control according to the hot water level difference ΔY is executed.

（湯面レベルの検出について）
連続鋳造操業においては、鋳型１内にパウダーを添加して、溶鋼の保温及び酸化防止、溶鋼中の介在物の吸収、凝固シェルの潤滑性の確保、抜熱の調整をする。これにより、鋳型内メニスカスでの凝固シェルを均一に生成して表面割れを防止し、鋳型と凝固シェルの焼き付きを防止する。
このように鋳型１内の湯面上にはパウダーが供給されることから、本発明では「パウダーによる抜熱の影響で湯面に垂直で上向きの熱流束値は、鋳型の他の部位と比べて最も大きくなる。」という推論に基づき、湯面レベルを検出する。 (About detection of hot water level)
In the continuous casting operation, powder is added into the mold 1 to keep the molten steel warm and prevent oxidation, absorb inclusions in the molten steel, ensure the lubricity of the solidified shell, and adjust the heat removal. As a result, a solidified shell is uniformly formed at the meniscus in the mold to prevent surface cracks, and seizure between the mold and the solidified shell is prevented.
Since powder is supplied onto the molten metal surface in the mold 1 in this way, in the present invention, “the heat flux value perpendicular to the molten metal surface and upward due to the effect of heat removal by the powder is compared with other parts of the mold. The hot water level is detected based on the inference that “It is the largest.”

以下、鋳型１に埋設された複数の熱電対６の計測データに基づいて、稼働面の熱流束ベクトルを推定する伝熱逆問題を説明する。
温度推定のための内外挿温度関数ｕ^*を、鋳型１に埋設された複数の熱電対６の時系列データセットに基づいて、鋳型１の鋳造方向−抜熱方向の２次元断面温度分布の時間変化を予測する数式を作成する。同式に基づいて、稼働面における熱流束ベクトル（大きさと向き）を求め、湯面レベル判定のための基本物理量とする。 Hereinafter, the inverse heat transfer problem for estimating the heat flux vector of the working surface based on the measurement data of the plurality of thermocouples 6 embedded in the mold 1 will be described.
Based on the time series data set of a plurality of thermocouples 6 embedded in the mold 1, the time of the two-dimensional cross-sectional temperature distribution in the casting direction and the heat removal direction of the mold 1 is used as the extrapolated temperature function u ^* for temperature estimation. Create mathematical formulas to predict changes. Based on this formula, the heat flux vector (size and direction) on the working surface is obtained and used as a basic physical quantity for determining the molten metal surface level.

図５に、伝熱逆問題の座標系を示す。空間ｘ軸は稼働面をｘ＝０とする抜熱方向、空間ｙ軸は鋳型１の上端をｙ＝０とする鋳造方向であり、これらに時間軸ｔを加えた時空間３次元座標を考える。
図５のプロットは、あるｙにおける空間ｘ−時間ｔの２次元断面図上の計算に使用する情報量の定義点を示す。ｘ軸の熱電対位置の情報量は熱電対６の計測データを使う。一方、水冷面の位置には熱電対が無いので、水冷熱伝達係数と水温を既知として決まる熱流束値を情報量に使い、上述した熱電対位置と併せ、測温データ採取点の領域と定義する。この領域をｙ軸方向にある熱電対位置に拡張し、空間ｘ−空間ｙ−時間ｔの３次元測温データ採取点の領域とする。
上述した３次元測温データ採取点の領域の情報量に基づいて作成した内外挿温度関数ｕ^*(ｘ，ｙ，ｔ)を使って、稼働面における熱流束ベクトルを推定する。 FIG. 5 shows a coordinate system for the inverse heat transfer problem. The space x-axis is the heat removal direction where the working surface is x = 0, and the space y-axis is the casting direction where the upper end of the mold 1 is y = 0. .
The plot of FIG. 5 shows the definition points of the information amount used for the calculation on the two-dimensional sectional view of the space x-time t at a certain y. The measurement data of the thermocouple 6 is used as the information amount of the thermocouple position on the x axis. On the other hand, since there is no thermocouple at the position of the water-cooled surface, the heat-cooled heat transfer coefficient and the heat flux value determined as the water temperature are used as the information amount, and together with the above-mentioned thermocouple position, it is defined as the temperature measurement data collection point area To do. This region is expanded to the thermocouple position in the y-axis direction, and is set as a region of the three-dimensional temperature measurement data collection point in space x-space y-time t.
The heat flux vector on the working surface is estimated using the interpolated temperature function u ^* (x, y, t) created based on the information amount of the region of the three-dimensional temperature measurement data collection point described above.

以下に、内外挿温度関数ｕ^*(ｘ，ｙ，ｔ)を構成するための数学手続きを述べる。
式（１）の非定常熱伝導方程式を考える。ここで、ａは鋳型１の熱拡散係数の平方根の物理量である。位置座標ｘ，ｙは[０，１]で規格化した。 The mathematical procedure for constructing the extrapolated temperature function u ^* (x, y, t) is described below.
Consider the unsteady heat conduction equation of equation (1). Here, a is a physical quantity of the square root of the thermal diffusion coefficient of the mold 1. The position coordinates x and y are normalized by [0, 1].

冷却面の境界条件を式（２）で表す。ここで、ｇ(ｔ)＝ｕ_wγとし、水温ｕ_wと熱伝達係数γの積として定義した。βは鋳型１の熱伝導率である。 The boundary condition of the cooling surface is expressed by equation (2). Here, g (t) = u _w γ, which is defined as the product of the water temperature u _w and the heat transfer coefficient γ. β is the thermal conductivity of the mold 1.

鋳型１の熱電対温度情報を式（３）で記述する。ｘ^*，ｙ^*は熱電対位置を表し、[０，１]で規格化している。 The thermocouple temperature information of the mold 1 is described by equation (3). x ^* and y ^* represent thermocouple positions and are normalized by [0, 1].

内外挿温度関数ｕ^*(ｘ，ｙ，ｔ)は後述する基底関数φを使い、式（４）で記述する。 The interpolated temperature function u ^* (x, y, t) is described by equation (4) using a basis function φ described later.

係数λ_jは、行列方程式（５）を解いて決定する。ここで、Ａは（ｍ＋ｌ）×（ｍ＋ｌ）行列、ｂは（ｍ＋ｌ）ベクトルである。ｘ_k，ｘ_s，ｔ_k，ｔ_sは上述の測温データ採取点の領域にある情報量の定義点である。一方、ｘ_j，ｔ_jは中心点と呼ばれる時空間座標上での基準点の座標であり、通常は、情報量の定義点と同一点を採用しておけばよい。 The coefficient λ _j is determined by solving the matrix equation (5). Here, A is an (m + 1) × (m + 1) matrix, and b is an (m + 1) vector. x _k , x _s , t _k , and t _s are definition points of the information amount in the region of the temperature measurement data collection point. On the other hand, x _j and t _j are the coordinates of the reference point on the spatio-temporal coordinate called the center point, and usually the same point as the definition point of the information amount may be adopted.

次に、基底関数φを、式（１）式を満足する基本解の形式を使い、式（６）、（７）のように定義する。 Next, the basis function φ is defined as in equations (6) and (7) using a basic solution format that satisfies equation (1).

ここで、Ｔは基本解の拡散プロフィールを調整するパラメータであり、Ｈ(ｔ)はヘビサイド関数である。稼働面における熱流束のｙ方向成分ｑ_yは、式（８）で計算することができる。ｋは鋳型材料の熱伝導率である。 Here, T is a parameter for adjusting the diffusion profile of the basic solution, and H (t) is a snake side function. The y-direction component q _y of the heat flux on the operating surface can be calculated by equation (8). k is the thermal conductivity of the mold material.

実機において、本発明の手法で湯面レベルを検出し、既存の手法で検出した湯面レベル及び実測の湯面レベルと比較した。図２に示すように、鋳型短辺２ａ、２ｂに熱電対６を埋設している。
本発明の手法では、図６（ｃ）、（ｄ）に示すように、稼動面における熱流束の鋳造方向のベクトル成分値を計算し、それが最大となる位置を湯面レベルと判定する。図６（ｃ）には、鋳型１内の温度分布（ドットが濃いほど高温であることを示す）と、稼動面における熱流束とを示す。図６（ｄ）には、稼動面における熱流束の鋳造方向のベクトル成分値を示す。 In the actual machine, the molten metal level was detected by the method of the present invention, and compared with the molten metal level detected by the existing method and the measured molten metal level. As shown in FIG. 2, thermocouples 6 are embedded in the mold short sides 2a and 2b.
In the method of the present invention, as shown in FIGS. 6C and 6D, the vector component value in the casting direction of the heat flux on the working surface is calculated, and the position where it becomes the maximum is determined as the molten metal surface level. FIG. 6C shows the temperature distribution in the mold 1 (the darker the dot, the higher the temperature) and the heat flux on the operating surface. In FIG.6 (d), the vector component value of the casting direction of the heat flux in an operation surface is shown.

一方、既存の手法では、図６（ｂ）に示すように、鋳型１内の温度分布を計算し、経験則に基づいて、最高温度×０．６５となる位置を湯面レベルと判定する。 On the other hand, in the existing method, as shown in FIG. 6B, the temperature distribution in the mold 1 is calculated, and the position where the maximum temperature × 0.65 is determined as the hot water level based on an empirical rule.

また、図７に示すように、湯面にフロート５０１を浮かべ、フロート５０１にロッド５０２を設けている。また、オッシレーション測定治具５０３を設定している。そして、ロッド５０２の先端、オッシレーション測定金物先端の動きをビデオカメラ５０４で撮影し、画像処理により垂直方向の変位をデジタル化し記録することにより、湯面レベルを実測した。 Further, as shown in FIG. 7, a float 501 is floated on the hot water surface, and a rod 502 is provided on the float 501. In addition, an oscillation measurement jig 503 is set. Then, the movement of the tip of the rod 502 and the tip of the oscillation measurement hardware were photographed by the video camera 504, and the vertical surface level was measured by digitizing and recording the displacement in the vertical direction by image processing.

図８に、本発明の手法で検出した湯面レベルと、既存の手法で検出した湯面レベルと、実測の湯面レベルとを示す。横軸は時間を、縦軸は湯面レベルを示す。
既存の手法では、実測の湯面レベルが高くなると検出精度が極端に低下し、実測値に追従できなくなっている。
それに対して、本発明の手法では、広範囲に亘り実測値を追従できているのがわかる。湯面レベルの実測精度が５−１０ｍｍ程度のバラツキがあることを勘案すると、本発明の手法により検出した湯面レベルは実測の湯面レベルと良い対応関係にあるといえる。 FIG. 8 shows the molten metal level detected by the technique of the present invention, the molten metal level detected by the existing technique, and the measured molten metal level. The horizontal axis represents time, and the vertical axis represents the hot water level.
In the existing method, when the measured hot water level becomes high, the detection accuracy is extremely lowered, and the measured value cannot be tracked.
On the other hand, it can be seen that the measured values can be tracked over a wide range in the method of the present invention. Considering that there is a variation in the measured accuracy of the molten metal level of about 5-10 mm, it can be said that the molten metal level detected by the method of the present invention has a good correspondence with the measured molten metal level.

以上述べたように、パウダーによる抜熱という湯面位置における熱移動の影響を捉えて湯面レベルを検出するので、湯面レベルの検出精度を高めることができる。 As described above, since the hot water level is detected by detecting the influence of heat transfer at the hot water surface position of heat removal by powder, the detection accuracy of the hot water level can be improved.

（制御部１０４の処理について）
図９に、制御部１０４が実行する制御処理を示す。
ステップＳ９０１で、制御部１０４は、湯面レベル差解析部１０３から湯面レベル差ΔＹを取得する。
ステップＳ９０２で、制御部１０４は、ステップＳ９０１で取得した湯面レベル差ΔＹが所定の値、本例では１０ｍｍを超えているか否かを判定する。１０ｍｍを超えていれば、偏流が発生しているとして、ステップＳ９０３に進む。１０ｍｍ以下であれば、偏流は発生していないとして、本処理を抜ける。
ステップＳ９０３で、制御部１０４は、鋳造速度を減少させる。本実施形態では、鋳造速度を、現在の鋳造速度よりも１０％以上減少させる。鋳造速度を減少させることにより、鋳型１内での溶鋼の流動を抑え、浸漬ノズル４の左右での溶鋼の偏流を抑えることができる。 (About processing of the control unit 104)
FIG. 9 shows a control process executed by the control unit 104.
In step S <b> 901, the control unit 104 acquires the molten metal level difference ΔY from the molten metal level difference analyzing unit 103.
In step S902, the control unit 104 determines whether or not the molten metal level difference ΔY acquired in step S901 exceeds a predetermined value, 10 mm in this example. If it exceeds 10 mm, it is determined that drift has occurred, and the process proceeds to step S903. If it is 10 mm or less, it is determined that no drift has occurred, and the process is terminated.
In step S903, the control unit 104 decreases the casting speed. In the present embodiment, the casting speed is reduced by 10% or more from the current casting speed. By reducing the casting speed, the flow of the molten steel in the mold 1 can be suppressed, and the drift of the molten steel on the left and right of the immersion nozzle 4 can be suppressed.

図１０は、図９のステップＳ９０３で鋳造速度を減少させた場合に制御部１０４が実行する制御処理を示す。
ステップＳ１００１で、制御部１０４は、湯面レベル差解析部１０３から湯面レベル差ΔＹを取得する。
ステップＳ１００２で、制御部１０４は、ステップＳ１００１で取得した湯面レベル差ΔＹが所定の値、本例では１０ｍｍ以下であるか否かを判定する。１０ｍｍ以下であれば、偏流は抑えられたとして、ステップＳ１００３に進む。１０ｍｍを超えていれば、偏流が発生しているとして、本処理を抜ける。
ステップＳ１００３で、制御部１０４は、現在の鋳造速度を、ステップＳ９０３で減少させる前の鋳造速度に復帰させる。 FIG. 10 shows a control process executed by the control unit 104 when the casting speed is reduced in step S903 of FIG.
In step S <b> 1001, the control unit 104 acquires the molten metal level difference ΔY from the molten metal level difference analyzing unit 103.
In step S1002, the control unit 104 determines whether or not the molten metal level difference ΔY acquired in step S1001 is a predetermined value, which is 10 mm or less in this example. If it is 10 mm or less, the drift is suppressed and the process proceeds to step S1003. If it exceeds 10 mm, it is determined that a drift has occurred and the process is exited.
In step S1003, the control unit 104 returns the current casting speed to the casting speed before the decrease in step S903.

ここで、本実施形態では、偏流の指標となる湯面レベル差ΔＹの閾値を１０ｍｍ、鋳造速度の減少率を１０％以上としたが、これは実績から得られた知見に基づくものである。
表１に、偏流に起因する欠陥（ヘゲ疵やスリバー疵）の発生率を示す。縦軸は湯面レベル差ΔＹを、横軸は鋳造速度を示す。ここでは、欠陥の発生率が０．７％以上となる範囲が、許容できない範囲であるとする（図中の白抜きの範囲）。
通常時の鋳造速度が１．４０ｍｐｍであるとする。鋳造速度が１．４０ｍｐｍの場合、湯面レベル差ΔＹが１０ｍｍを超えると、許容できない欠陥が発生する。この場合に、鋳造速度を１．３５ｍｐｍに減少させても（３．６％の減少）、鋳造速度を１．３０ｍｐｍに減少させても（７．１％の減少）、許容できない欠陥が発生するが、鋳造速度を１．２５ｍｐｍに減少させると（１０．７％の減少）、欠陥の発生率は許容範囲に収まることがわかる。 Here, in this embodiment, the threshold value of the molten metal surface level difference ΔY, which is an indicator of drift, is set to 10 mm, and the rate of reduction of the casting speed is set to 10% or more. This is based on knowledge obtained from actual results.
Table 1 shows the occurrence rate of defects (hege defects and sliver defects) due to drift. The vertical axis represents the molten metal level difference ΔY, and the horizontal axis represents the casting speed. Here, it is assumed that the range in which the defect occurrence rate is 0.7% or more is an unacceptable range (the white range in the figure).
It is assumed that the normal casting speed is 1.40 mpm. When the casting speed is 1.40 mpm, an unacceptable defect occurs when the molten metal level difference ΔY exceeds 10 mm. In this case, even if the casting speed is reduced to 1.35 mpm (a reduction of 3.6%) or the casting speed is reduced to 1.30 mpm (a reduction of 7.1%), unacceptable defects occur. However, when the casting speed is reduced to 1.25 mpm (a reduction of 10.7%), it can be seen that the defect generation rate falls within the allowable range.

以上述べたように、湯面位置における熱移動の影響を捉えて湯面レベルを検出することにより湯面レベルの検出精度を高め、鋳型内の偏流の検知精度向上を図り、鋳片品質の安定化を実現することができる。 As described above, the detection accuracy of the molten metal level is improved by detecting the level of the molten metal level by detecting the influence of heat transfer at the molten metal surface position, and the detection accuracy of the drift in the mold is improved, and the quality of the slab is stabilized. Can be realized.

なお、本実施形態では、湯面レベル差ΔＹが所定の値を超えたとき、鋳造速度を減少させる制御を実行する例を説明したが、それに限定されるものではない。例えば湯面レベル差ΔＹが所定の値を超えた状態で鋳型１を通過した鋳片については、一級品への充当を取りやめる、すなわち二級品に充当するといった取り扱いとしてもよい。 In the present embodiment, the example in which the control for reducing the casting speed is performed when the molten metal level difference ΔY exceeds a predetermined value has been described, but the present invention is not limited to this. For example, for a slab that has passed through the mold 1 in a state where the molten metal surface level difference ΔY exceeds a predetermined value, it may be handled such that application to a first-class product is canceled, that is, application to a second-class product.

また、本実施形態では、浸漬ノズル４の吐出方向に位置する鋳型短辺２ａ、２ｂに熱電対６を埋設したが、鋳型長辺３ａ、３ｂに熱電対６を埋設してもよい。ただし、偏流を捉えるためには、一定の流動距離を確保するとともに、浸漬ノズル４の吐出流が衝突する鋳型短辺２ａ、２ｂ付近での湯面レベルを捉える必要があることから、鋳型長辺３ａ、３ｂのうち鋳型短辺２ａ、２ｂに近い位置に熱電対６を配置、埋設するのが好ましい。具体的には、浸漬ノズル４の中心から左右鋳型短辺２ａ、２ｂまでの鋳型長辺幅方向距離をそれぞれＷ／２とした場合に、鋳型長辺３ａ、３ｂにおいて、浸漬ノズル４の中心から３Ｗ／８より遠くに熱電対６を配置、埋設する。 Further, in the present embodiment, the thermocouple 6 is embedded in the mold short sides 2a and 2b located in the discharge direction of the immersion nozzle 4, but the thermocouple 6 may be embedded in the mold long sides 3a and 3b. However, in order to catch the uneven flow, it is necessary to secure a constant flow distance and to catch the molten metal surface level near the mold short sides 2a and 2b where the discharge flow of the immersion nozzle 4 collides. It is preferable to arrange and embed the thermocouple 6 at a position close to the mold short sides 2a and 2b in 3a and 3b. Specifically, when the mold long side width direction distance from the center of the immersion nozzle 4 to the left and right mold short sides 2a and 2b is W / 2, respectively, the mold long sides 3a and 3b from the center of the immersion nozzle 4 The thermocouple 6 is arranged and buried farther than 3W / 8.

［第２の実施形態］
第２の実施形態として、鋳型内の湯面変動を検知し、必要に応じて湯面変動を抑制するように鋳造速度を制御する例を説明する。なお、第１の実施形態で説明したものについての説明は省略し、第１の実施形態との相違を中心に説明する。 [Second Embodiment]
As a second embodiment, an example will be described in which the molten metal level fluctuation in the mold is detected and the casting speed is controlled to suppress the molten metal level fluctuation as necessary. In addition, description about what was demonstrated in 1st Embodiment is abbreviate | omitted, and it demonstrates centering around difference with 1st Embodiment.

一対の鋳型長辺３ａ、３ｂには、鋳造方向に複数の熱電対６が配置、埋設される。図１２に示すように、本実施形態では、鋳型長辺３ａ、３ｂに、それぞれ２列で熱電対６を配置、埋設する。鋳型１内に流入する溶鋼流量に起因する湯面変動を捉えることから、偏流の影響をさけるために、浸漬ノズル４の吐出流が衝突する鋳型短辺２ａ、２ｂから離れた位置での湯面レベルを捉えるのが好ましい。そこで、浸漬ノズル４の中心から左右鋳型短辺２ａ、２ｂまでの鋳型長辺幅方向距離をそれぞれＷ／２とした場合に、鋳型長辺３ａ、３ｂにおいて、浸漬ノズル４の中心から３Ｗ／８以内に熱電対６を配置、埋設する。 A plurality of thermocouples 6 are arranged and embedded in the pair of mold long sides 3a and 3b in the casting direction. As shown in FIG. 12, in this embodiment, the thermocouples 6 are arranged and embedded in two long rows on the long mold sides 3a and 3b. In order to avoid the influence of drift, the molten metal surface at a position away from the mold short sides 2a and 2b where the discharge flow of the immersion nozzle 4 collides is detected in order to capture the fluctuation of the molten metal surface caused by the flow rate of molten steel flowing into the mold 1. It is preferable to capture the level. Therefore, assuming that the mold long side width direction distance from the center of the immersion nozzle 4 to the left and right mold short sides 2a and 2b is W / 2, respectively, the mold long sides 3a and 3b are 3W / 8 from the center of the immersion nozzle 4. The thermocouple 6 is placed and buried within.

本実施形態では、図１３に示すように、湯面変動の指標として、湯面変動速度Ｖ_Yを求める。
なお、本実施形態では、複数列で熱電対６を配置する例を説明した。このように複数列で熱電対６を配置する場合、例えば、列ごとに熱電対６の計測値を用いて湯面レベルを推定し、これら湯面レベルの平均値を現在の湯面レベルとして取り扱い、湯面変動速度Ｖ_Yを求めるようにすればよい。また、一の鋳型長辺の１列だけに熱電対６を配置、埋設するようにしてもよい。 In the present embodiment, as shown in FIG. 13, the molten metal surface fluctuation speed V _Y is obtained as an index of the molten metal surface fluctuation.
In the present embodiment, the example in which the thermocouples 6 are arranged in a plurality of rows has been described. When the thermocouples 6 are arranged in a plurality of rows in this way, for example, the molten metal surface level is estimated using the measured value of the thermocouple 6 for each column, and the average value of these molten metal surface levels is handled as the current molten metal surface level. The hot water surface fluctuation speed V _Y may be obtained. Further, the thermocouple 6 may be arranged and embedded only in one row of one mold long side.

図１４に、連続鋳造鋳型内の湯面変動制御装置２００の機能構成を示す。なお、本実施形態では、湯面変動制御装置２００が本発明を適用した連続鋳造鋳型内の湯面変動検知装置としても機能する。
２０１は入力部であり、鋳型長辺３ａ、３ｂの鋳造方向に配置、埋設された複数の熱電対６の計測値を入力する。
２０２は計算部であり、第１の実施形態で説明した計算部１０２と同様、入力部２０１で入力した熱電対６の計測値を用いて伝熱逆問題を解き、稼動面における熱流束の鋳造方向のベクトル成分値、換言すれば稼動面における熱流束の湯面に垂直な方向のベクトル成分値を計算する。
２０３は湯面変動解析部であり、計算部２０２で計算した稼動面における熱流束の鋳造方向と逆向きとなる湯面の法線方向のベクトル成分値が最大となる位置を湯面レベルと判定し、湯面変動速度Ｖ_Yを求める。
２０４は制御部であり、詳細は後述するが、湯面変動解析部２０３で求めた湯面変動速度Ｖ_Yに基づいて、湯面変動を抑制するように鋳造速度を制御する。
入力部２０１、計算部２０２、湯面変動解析部２０３、及び制御部２０４は、例えば一定周期で、熱電対６の計測値の入力、ベクトル成分値の計算、湯面変動速度Ｖ_Yの計算、及び湯面変動速度Ｖ_Yに応じた制御を実行する。 In FIG. 14, the function structure of the hot_water | molten_metal surface fluctuation | variation control apparatus 200 in a continuous casting mold is shown. In the present embodiment, the molten metal surface fluctuation control device 200 also functions as a molten metal surface fluctuation detection device in a continuous casting mold to which the present invention is applied.
Reference numeral 201 denotes an input unit that inputs measurement values of a plurality of thermocouples 6 arranged and embedded in the casting direction of the mold long sides 3a and 3b.
Reference numeral 202 denotes a calculation unit, which, like the calculation unit 102 described in the first embodiment, solves the inverse heat transfer problem using the measured value of the thermocouple 6 input by the input unit 201 and casts the heat flux on the operating surface. The vector component value in the direction, in other words, the vector component value in the direction perpendicular to the surface of the heat flux on the operating surface is calculated.
A molten metal level fluctuation analysis unit 203 determines the position where the vector component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated by the calculating unit 202 is the molten metal surface level. Then, the molten metal surface fluctuation speed V _Y is obtained.
Reference numeral 204 denotes a control unit, which will be described in detail later, and controls the casting speed so as to suppress the molten metal surface fluctuation based on the molten metal surface fluctuation speed V _Y obtained by the molten metal surface fluctuation analyzing unit 203.
The input unit 201, the calculation unit 202, the hot water level fluctuation analysis unit 203, and the control unit 204 are, for example, at regular intervals, input of measured values of the thermocouple 6, calculation of vector component values, calculation of the hot water level fluctuation speed V _Y , and performs control according to bath level changing speed V _Y.

（制御部２０４の処理について）
図１５に、制御部２０４が実行する制御処理を示す。本実施形態では、計算部２０２において、湯面変動速度Ｖ_Yとして、３０秒単位での湯面変動量（ｍｍ）を求めるものとする。
ステップＳ１５０１で、制御部２０４は、湯面変動解析部２０３から湯面変動速度Ｖ_Yを取得する。
ステップＳ１５０２で、制御部２０４は、ステップＳ１５０１で取得した湯面変動速度Ｖ_Yが所定の値、本例では１０ｍｍ毎３０秒以上となっているか否かを判定する。１０ｍｍ毎３０秒以上であれば、急激な湯面変動が発生しているとして、ステップＳ１５０３に進む。１０ｍｍ毎３０秒を下回っていれば、急激な湯面変動は発生していないとして、本処理を抜ける。
ステップＳ１５０３で、制御部２０４は、鋳造速度を減少させる。本実施形態では、鋳造速度を、現在の鋳造速度よりも１０％以上減少させる。鋳造速度を減少させることにより、急激な湯面変動を抑えることができる。 (About processing of the control unit 204)
FIG. 15 shows control processing executed by the control unit 204. In the present embodiment, the calculation unit 202 calculates the molten metal surface fluctuation amount (mm) in units of 30 seconds as the molten metal surface fluctuation speed V _Y.
In step S1501, the control unit 204 obtains the molten metal surface fluctuation speed V _Y from the molten metal surface fluctuation analyzing unit 203.
In step S1502, the control unit 204 determines whether or not the molten metal surface fluctuation speed V _Y acquired in step S1501 is a predetermined value, in this example, 10 mm every 30 seconds or more. If it is 10 seconds or more for 30 seconds or more, it is determined that rapid molten metal level fluctuation has occurred, and the process proceeds to step S1503. If the time is less than 30 seconds per 10 mm, it is determined that no rapid melt level change has occurred, and the present process is exited.
In step S1503, the control unit 204 decreases the casting speed. In the present embodiment, the casting speed is reduced by 10% or more from the current casting speed. By reducing the casting speed, it is possible to suppress rapid fluctuations in the molten metal surface.

図１６は、図１５のステップＳ１５０３で鋳造速度を減少させた場合に制御部２０４が実行する制御処理を示す。
ステップＳ１６０１で、制御部２０４は、湯面変動解析部２０３から湯面変動速度Ｖ_Yを取得する。
ステップＳ１６０２で、制御部２０４は、ステップＳ１６０１で取得した湯面変動速度Ｖ_Yが所定の値、本例では１０ｍｍ毎３０秒を下回っているか否かを判定する。１０ｍｍ毎３０秒を下回っていれば、急激な湯面変動は抑えられたとして、ステップＳ１６０３に進む。１０ｍｍ毎３０秒以上であれば、急激な湯面変動が発生しているとして、本処理を抜ける。
ステップＳ１６０３で、制御部２０４は、現在の鋳造速度を、ステップＳ１５０３で減少させる前の鋳造速度に復帰させる。 FIG. 16 shows a control process executed by the control unit 204 when the casting speed is reduced in step S1503 of FIG.
In step S <b> 1601, the control unit 204 acquires the molten metal surface fluctuation speed V _Y from the molten metal surface fluctuation analyzing unit 203.
In step S1602, the control unit 204 determines whether the melt surface changing speed V _Y acquired in step S1601 is smaller than a predetermined value, a 10mm every 30 seconds in the present example. If the time is less than 10 mm every 30 seconds, it is determined that the rapid fluctuation of the molten metal surface is suppressed, and the process proceeds to step S1603. If it is 10 seconds or more for 30 seconds or more, it is determined that a rapid change in the molten metal surface has occurred, and the process is exited.
In step S1603, the control unit 204 returns the current casting speed to the casting speed before being decreased in step S1503.

ここで、本実施形態では、湯面変動の指標となる湯面変動速度Ｖ_Yの閾値を１０ｍｍ毎３０秒、鋳造速度の減少率を１０％以上としたが、これは実績から得られた知見に基づくものである。
表２に、湯面変動に起因する欠陥（ヘゲ疵やスリバー疵）の発生率を示す。縦軸は湯面変動速度Ｖ_Yを、横軸は鋳造速度を示す。ここでは、欠陥の発生率が０．７％以上となる範囲が、許容できない範囲であるとする（図中の白抜きの範囲）。
通常時の鋳造速度が１．４０ｍｐｍであるとする。鋳造速度が１．４０ｍｐｍの場合、湯面変動速度Ｖ_Yが１０ｍｍ毎３０秒以上となると、許容できない欠陥が発生する。この場合に、鋳造速度を１．３５ｍｐｍに減少させても（３．６％の減少）、鋳造速度を１．３０ｍｐｍに減少させても（７．１％の減少）、許容できない欠陥が発生するが、鋳造速度を１．２５ｍｐｍに減少させると（１０．７％の減少）、欠陥の発生率は許容範囲に収まることがわかる。 Here, in the present embodiment, the threshold value of the molten metal surface fluctuation speed V _{Y serving} as an index of the molten metal surface fluctuation is set to 30 seconds every 10 mm and the reduction rate of the casting speed is set to 10% or more. It is based on.
Table 2 shows the rate of occurrence of defects (hege wrinkles and sliver wrinkles) due to molten metal surface fluctuations. The vertical axis represents the molten metal surface fluctuation speed V _Y , and the horizontal axis represents the casting speed. Here, it is assumed that the range in which the defect occurrence rate is 0.7% or more is an unacceptable range (the white range in the figure).
It is assumed that the normal casting speed is 1.40 mpm. When the casting speed is 1.40 mpm, an unacceptable defect occurs when the molten metal surface fluctuation speed V _Y is 30 seconds or more every 10 mm. In this case, even if the casting speed is reduced to 1.35 mpm (a reduction of 3.6%) or the casting speed is reduced to 1.30 mpm (a reduction of 7.1%), unacceptable defects occur. However, when the casting speed is reduced to 1.25 mpm (a reduction of 10.7%), it can be seen that the defect generation rate falls within the allowable range.

以上述べたように、湯面位置における熱移動の影響を捉えて湯面レベルを検出することにより湯面レベルの検出精度を高め、鋳型内の湯面変動の検知精度向上を図り、鋳片品質の安定化を実現することができる。 As described above, the detection accuracy of the molten metal level is improved by detecting the level of the molten metal level by detecting the influence of heat transfer at the molten metal surface position, and the detection accuracy of the molten metal surface level in the mold is improved. Can be realized.

以上、本発明を種々の実施形態と共に説明したが、本発明はこれらの実施形態にのみ限定されるものではなく、本発明の範囲内で変更等が可能である。
本発明を適用した連続鋳造鋳型内の偏流検知装置、偏流制御装置、湯面変動検知装置、湯面変動制御装置は、例えばＣＰＵ、ＲＯＭ、ＲＡＭ等を備えたコンピュータ装置により実現することが可能である。
また、本発明は、連続鋳造鋳型内の偏流検知機能、偏流制御機能、湯面変動検知機能、湯面変動制御機能を実現するソフトウェア（プログラム）を、ネットワーク又は各種記憶媒体を介してシステム或いは装置に供給し、そのシステム或いは装置のコンピュータがプログラムを読み出して実行することによっても実現可能である。 As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
The drift detection device, drift control device, melt level fluctuation detection device, and melt level fluctuation control device in the continuous casting mold to which the present invention is applied can be realized by a computer device including, for example, a CPU, a ROM, a RAM, and the like. is there.
In addition, the present invention provides a system or apparatus for software (program) for realizing a drift detection function, drift control function, melt level fluctuation detection function, and melt level fluctuation control function in a continuous casting mold via a network or various storage media. This can also be realized by reading out and executing the program by the computer of the system or apparatus.

１：連続鋳造鋳型、２ａ、２ｂ：鋳型短辺、３ａ、３ｂ：鋳型長辺、４：浸漬ノズル、５：湯面、６：熱電対、１００：連続鋳造鋳型内の偏流制御装置、１０１：入力部、１０２：計算部、１０３：湯面レベル差解析部、１０４：制御部、２００：連続鋳造鋳型内の湯面変動制御装置、２０１：入力部、２０２：計算部、２０３：湯面変動解析部、２０４：制御部 1: continuous casting mold, 2a, 2b: mold short side, 3a, 3b: mold long side, 4: immersion nozzle, 5: molten metal surface, 6: thermocouple, 100: drift control device in continuous casting mold, 101: Input unit 102: Calculation unit 103: Molten surface level difference analysis unit 104: Control unit 200: Molten surface fluctuation control device in continuous casting mold 201: Input unit 202: Calculation unit 203: Molten surface fluctuation Analysis unit, 204: control unit

Claims

A method of detecting drift in a continuous casting mold,
An acquisition step of acquiring measurement values of a plurality of temperature detection means arranged and embedded in each casting direction of a pair of mold sides facing each other across the immersion nozzle;
A calculation step for solving the inverse heat transfer problem using the measurement value of the temperature detection means acquired in the acquisition step and calculating a component value in the casting direction of the heat flux on the working surface;
Based on the component value in the casting direction of the heat flux on the operating surface calculated in the calculating step, the molten metal surface level is determined, and a molten metal surface level difference analyzing step for obtaining a molten metal surface level difference on the operating surface of the pair of mold sides; I have a,
In the molten metal surface level difference analyzing step, the position where the component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated in the calculating step is determined as the molten metal surface level. A method for detecting drift in a continuous casting mold.

A drift control method in a continuous casting mold, wherein the casting speed is decreased when a difference in molten metal level obtained by the drift detection method in the continuous casting mold according to claim 1 exceeds a predetermined value.

3. The drift control method in a continuous casting mold according to claim 2 , wherein when the molten metal level difference exceeds 10 mm, the casting speed is reduced by 10% or more.

A method for detecting a change in molten metal level in a continuous casting mold,
An acquisition step of acquiring measurement values of a plurality of temperature detection means arranged and embedded in the casting direction of the continuous casting mold,
A calculation step for solving the inverse heat transfer problem using the measurement value of the temperature detection means acquired in the acquisition step and calculating a component value in the casting direction of the heat flux on the working surface;
The calculation based on the component values of the casting direction of the heat flux in operation plane calculated in step, to determine the melt-surface levels, possess a melt surface variation analysis step of obtaining a melt surface variation rate,
In the molten metal surface fluctuation analyzing step, the position where the component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated in the calculating step is determined as the molten metal surface level. A method for detecting fluctuations in the molten metal level in a continuous casting mold.

When the mold long side width direction distance from the center of the immersion nozzle to the short side of the left and right molds is W / 2, respectively, the temperature detection means is arranged within 3 W / 8 from the center of the immersion nozzle on the long side of the mold. The method for detecting fluctuations in molten metal level in a continuous casting mold according to claim 4 , wherein the method is embedded.

The casting speed is reduced when the molten metal surface fluctuation speed obtained by the method for detecting fluctuation of molten metal surface in the continuous casting mold according to claim 4 or 5 exceeds a predetermined value. Hot water level fluctuation control method.

7. The method for controlling fluctuations in a molten metal surface in a continuous casting mold according to claim 6 , wherein when the molten metal surface fluctuation speed becomes 30 seconds or more per 10 mm, the casting speed is reduced by 10% or more.

A drift detection device in a continuous casting mold,
An input means for inputting measurement values of a plurality of temperature detection means arranged and embedded in each casting direction of a pair of mold sides facing each other across the immersion nozzle;
A calculation means for solving the inverse heat transfer problem using the measured value of the temperature detection means input by the input means, and calculating a component value in the casting direction of the heat flux on the working surface;
Based on the component value in the casting direction of the heat flux on the operating surface calculated by the calculating means, the molten metal surface level is determined, and the molten metal surface level difference analyzing means for obtaining the molten metal surface level difference on the operating surface of the pair of mold sides; equipped with a,
The molten metal level difference analyzing means determines the position where the component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated by the calculating means is the molten metal surface level. A drift detection device in a continuous casting mold characterized by the above.

A hot water level fluctuation detection device in a continuous casting mold,
Input means for inputting measurement values of a plurality of temperature detection means arranged and embedded in the casting direction of the continuous casting mold,
A calculation means for solving the inverse heat transfer problem using the measured value of the temperature detection means input by the input means, and calculating a component value in the casting direction of the heat flux on the working surface;
Based on the component value in the casting direction of the heat flux on the working surface calculated by the calculating means, the molten metal surface level is determined, and the molten metal surface fluctuation analyzing means for obtaining the molten metal surface fluctuation speed is provided .
The molten metal surface fluctuation analyzing means determines that the position at which the component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated by the calculating device is the maximum is the molten metal surface level. An apparatus for detecting fluctuations in the molten metal level in a continuous casting mold.

A program for detecting drift in a continuous casting mold,
An input process for inputting the measurement values of a plurality of temperature detection means arranged and embedded in the casting direction of each of a pair of mold sides facing each other across the immersion nozzle,
A calculation process for solving a heat transfer inverse problem using the input measurement value of the temperature detection means and calculating a component value in the casting direction of the heat flux on the working surface;
Based on the component value in the casting direction of the heat flux on the calculated working surface, the molten metal level level is determined, and a molten metal level difference analysis process for obtaining a molten metal level difference on the working surface of the pair of mold sides is performed on a computer. to be executed,
In the molten metal surface level difference analysis process, the position where the component value in the normal direction of the molten metal surface that is opposite to the casting direction of the heat flux on the operating surface calculated in the calculation process is determined as the molten metal surface level. A program characterized by

A program for detecting the fluctuation of the molten metal surface in a continuous casting mold,
An input process for inputting measurement values of a plurality of temperature detection means arranged and embedded in the casting direction of the continuous casting mold,
A calculation process for solving a heat transfer inverse problem using the input measurement value of the temperature detection means and calculating a component value in the casting direction of the heat flux on the working surface;
Based on the component value in the casting direction of the heat flux on the calculated operating surface, the molten metal surface level is determined, and the molten metal surface fluctuation analyzing process for obtaining the molten metal surface fluctuation speed is executed by a computer ,
In the molten metal surface fluctuation analysis process, the position where the component value in the normal direction of the molten metal surface opposite to the casting direction of the heat flux on the operating surface calculated in the calculation process is determined as the molten metal surface level. A featured program.