JP6558060B2 - Thick steel plate cooling control method, cooling control device, manufacturing method, and manufacturing device - Google Patents
Thick steel plate cooling control method, cooling control device, manufacturing method, and manufacturing device Download PDFInfo
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Description
本発明は、熱間圧延された厚鋼板の冷却形態を制御する冷却制御方法およびこれを用いる厚鋼板の製造方法、並びに、熱間圧延された厚鋼板の冷却形態を制御する冷却制御装置およびこれを用いる厚鋼板の製造装置に関する。 The present invention relates to a cooling control method for controlling the cooling mode of a hot-rolled thick steel plate, a method for manufacturing the thick steel plate using the same, a cooling control device for controlling the cooling mode of the hot-rolled thick steel plate, and the same The present invention relates to an apparatus for manufacturing a thick steel plate.
熱間圧延された厚鋼板を加速冷却し、焼入れ効果などを得るようにした厚鋼板の製造ラインが、広く厚鋼板の製造に使用されている。この熱間圧延された厚鋼板の冷却は、厚鋼板の材質造り込みの観点から非常に重要な工程であり、その特性を決定する要因としては、厚鋼板の冷却開始温度、厚鋼板の冷却速度、および、厚鋼板の冷却停止温度を挙げることができる。 2. Description of the Related Art A thick steel plate production line in which hot-rolled thick steel plates are accelerated and cooled to obtain a quenching effect or the like is widely used for the production of thick steel plates. The cooling of the hot-rolled thick steel plate is a very important process from the viewpoint of building the material of the thick steel plate, and the factors that determine its characteristics include the cooling start temperature of the thick steel plate and the cooling rate of the thick steel plate. And a cooling stop temperature of the thick steel plate.
上記の要因のうち、厚鋼板の冷却開始温度は仕上圧延工程の仕上温度で決まり、厚鋼板の冷却速度は所望の材質造り込みにおいて、製造する厚鋼板毎に概ね指示されている。したがって、実プロセスにおける冷却制御においては、厚鋼板の冷却停止温度が最も重要である。また、均一な特性を持った厚鋼板を製造するためには、厚鋼板の長手方向および幅方向における冷却停止温度の温度むらが極力小さいことが求められる。 Among the above factors, the cooling start temperature of the thick steel plate is determined by the finishing temperature of the finish rolling process, and the cooling rate of the thick steel plate is generally instructed for each thick steel plate to be manufactured in the desired material building. Therefore, in the cooling control in the actual process, the cooling stop temperature of the thick steel plate is the most important. Moreover, in order to manufacture a thick steel plate having uniform characteristics, it is required that the temperature unevenness of the cooling stop temperature in the longitudinal direction and the width direction of the thick steel plate is as small as possible.
従来から、例えば特許文献１等のように、冷却しつつ通板されている厚鋼板の温度を計測し、冷却停止温度が所望の温度になるように厚鋼板に噴射する冷却水量を変動させて、温度誤差を修正するようにした冷却制御方法が開示されている。
また、特許文献２や特許文献３には、厚鋼板の長手方向の温度むらを抑制するため、厚鋼板の搬送速度を制御する方法や、冷却装置の水冷条件を最適化する方法が提案されている。
また、特許文献４には、厚鋼板の平坦度を確保するため、厚鋼板の上下面温度差を検出し、検出した上下面温度差に基づいて上下注水量比を修正制御する方法が提案されている。
Conventionally, as in Patent Document 1, for example, the temperature of a thick steel plate that is being passed through while cooling is measured, and the amount of cooling water sprayed on the thick steel plate is varied so that the cooling stop temperature becomes a desired temperature. A cooling control method for correcting a temperature error is disclosed.
Patent Document 2 and Patent Document 3 propose a method for controlling the conveying speed of the thick steel plate and a method for optimizing the water cooling conditions of the cooling device in order to suppress temperature unevenness in the longitudinal direction of the thick steel plate. Yes.
Patent Document 4 proposes a method for detecting the temperature difference between the upper and lower surfaces of the thick steel plate and correcting the upper and lower water injection amount ratio based on the detected upper and lower surface temperature difference in order to ensure the flatness of the thick steel plate. ing.
厚鋼板の特性を均一化するためには、冷却に際して厚鋼板の長手方向および幅方向の温度むらを抑制し、且つ、冷却後の厚鋼板の平坦度を高めることが必要になる。しかしながら、従来の技術では、厚鋼板の長手方向の温度むら、厚鋼板の幅方向の温度むら、および、冷却後の厚鋼板の平坦度の相関について検討していないため、厚鋼板の長手方向および幅方向の温度むらを抑制しつつ厚鋼板の平坦度を高める冷却制御を行うことは困難であった。 In order to make the properties of the thick steel plate uniform, it is necessary to suppress temperature unevenness in the longitudinal direction and the width direction of the thick steel plate during cooling and to increase the flatness of the thick steel plate after cooling. However, in the prior art, since the temperature unevenness in the longitudinal direction of the thick steel plate, the temperature unevenness in the width direction of the thick steel plate, and the correlation of the flatness of the thick steel plate after cooling are not examined, the longitudinal direction of the thick steel plate and It has been difficult to perform cooling control that increases the flatness of the thick steel plate while suppressing temperature unevenness in the width direction.
本発明は、上記問題点に鑑みてなされたものであって、長手方向および幅方向の温度むらを抑制するとともに、冷却後の厚鋼板の平坦度を高めることが可能な、厚鋼板の冷却制御方法および冷却制御装置並びに厚鋼板の製造方法および製造装置を提供することを課題
とする。
The present invention has been made in view of the above-described problems, and is capable of suppressing the temperature unevenness in the longitudinal direction and the width direction, and capable of increasing the flatness of the thick steel plate after cooling. It is an object of the present invention to provide a method, a cooling control device, a method of manufacturing a thick steel plate, and a manufacturing device.
発明者らは鋭意研究した結果、以下の知見を得て本発明を完成させた。
１）厚鋼板の長手方向の温度むら、厚鋼板の幅方向の温度むら、および、冷却後の厚鋼板の平坦度には相関があり、単純にそれぞれを調整しただけでは、適切な冷却制御を行うことは困難である。
２）厚鋼板の冷却時に、上下水量比（定義は後述）を変えることにより、冷却後の厚鋼板の平坦度が変化する。冷却後の厚鋼板の平坦度を高めるためには、上下水量比を調整することが有効である。また、前後段冷却比（定義は後述）を変えることでも、冷却後の厚鋼板の平坦度が変化する。冷却後の厚鋼板の平坦度を高めるためには、前後段冷却比の影響も加味して上下水量比を調整することが、さらに効果的である。
３）冷却実験および数値実験（シミュレーション）により、冷却装置の設定因子が厚鋼板の幅方向の温度むらに与える影響の度合いをモデル化することにより、厚鋼板の幅方向の温度むらを予測することができる。このとき、冷却後の厚鋼板の平坦度を確保するために、決定した上下水量比を冷却装置の設定因子の一つとして利用することにより、冷却後の厚鋼板の平坦度を確保しつつ、厚鋼板の幅方向の温度むらが所定値以下となるように、予測結果を用いて厚鋼板の板幅方向の流量分布パターン（以下において、「流量クラウン量」ということがある。）を決定することが可能になる。
４）さらに、上下水量比および流量クラウン量を基に、厚鋼板を冷却する冷却装置の各冷却ゾーンにおける水量密度を、厚鋼板の冷却中に冷却水の水量を変動させるように制御（以下において、「ダイナミック制御」ということがある。）することにより、厚鋼板の板幅中央部における長手方向の温度むらを高精度に制御することが可能になる。
As a result of intensive studies, the inventors obtained the following knowledge and completed the present invention.
1) The temperature unevenness in the longitudinal direction of the thick steel plate, the temperature unevenness in the width direction of the thick steel plate, and the flatness of the thick steel plate after cooling are correlated, and appropriate cooling control can be achieved simply by adjusting each. It is difficult to do.
2) When the thick steel plate is cooled, the flatness of the thick steel plate after cooling is changed by changing the ratio of the amount of water and water (definition will be described later). In order to increase the flatness of the thick steel plate after cooling, it is effective to adjust the water / water ratio. Moreover, the flatness of the thick steel plate after cooling also changes by changing the front-rear cooling ratio (the definition will be described later). In order to increase the flatness of the thick steel plate after cooling, it is more effective to adjust the water / water ratio by taking into account the influence of the front / rear cooling ratio.
3) Predicting the temperature unevenness in the width direction of the thick steel sheet by modeling the degree of influence of the setting factor of the cooling device on the temperature unevenness in the width direction of the thick steel sheet by cooling experiments and numerical experiments (simulations). Can do. At this time, in order to ensure the flatness of the thick steel plate after cooling, by using the determined water / water ratio as one of the setting factors of the cooling device, while ensuring the flatness of the thick steel plate after cooling, A flow distribution pattern in the plate width direction of the thick steel plate (hereinafter, also referred to as “flow crown amount”) is determined using the prediction result so that the temperature unevenness in the width direction of the thick steel plate is not more than a predetermined value. It becomes possible.
4) Further, based on the water flow ratio and the flow crown amount, the water density in each cooling zone of the cooling device for cooling the thick steel plate is controlled so that the cooling water amount fluctuates during the cooling of the thick steel plate (in the following) , Sometimes referred to as “dynamic control”), it becomes possible to control the temperature unevenness in the longitudinal direction at the central portion of the plate width of the thick steel plate with high accuracy.
以下、本発明について説明する。 The present invention will be described below.
本発明の第１の態様は、冷却装置の水冷ゾーンを通過させる厚鋼板の冷却を制御する方法であって、過去の製造実績から、冷却される厚鋼板の平坦度合格率が所定値以上になる冷却装置の上下水量比を決定する工程と、決定された上下水量比、および、これ以外の製造条件から、厚鋼板の幅方向における冷却後の温度分布を予測する工程と、予測した冷却後の温度分布の幅が一定値以下になる、厚鋼板の幅方向における冷却水の流量分布を決定する工程と、決定された上下水量比、および、決定された冷却水の流量分布となるように、冷却装置へと供給される冷却水の水量を、厚鋼板の冷却中に変動させるように制御する工程と、を有する、厚鋼板の冷却制御方法である。 A first aspect of the present invention is a method for controlling cooling of a thick steel plate that passes through a water-cooling zone of a cooling device, and the flatness pass rate of the cooled thick steel plate is a predetermined value or more based on past production results. A step of determining the water / water ratio of the cooling device to be determined, a step of predicting the temperature distribution after cooling in the width direction of the steel plate from the determined water / water ratio, and other manufacturing conditions, and the predicted after cooling The step of determining the flow rate distribution of the cooling water in the width direction of the thick steel plate, the determined water / water ratio, and the determined flow rate distribution of the cooling water so that the temperature distribution width of And a step of controlling the amount of cooling water supplied to the cooling device to vary during cooling of the thick steel plate.
ここに、「冷却装置の上下水量比」とは、冷却装置を用いて冷却される厚鋼板の上面側に配置されている冷却ヘッダーへと供給される冷却水量をα、当該厚鋼板の下面側に配置されている冷却ヘッダーへと供給される冷却水量をβとするとき、ＲＴＢ＝α／βで導かれるＲＴＢをいう。また、「これ以外の製造条件」には、具体的には、冷却装置の入側における厚鋼板の表面温度の実績値、冷却装置の出側における厚鋼板の表面温度の実績値、厚鋼板の板厚、厚鋼板の板幅、厚鋼板の搬送速度、冷却装置の各冷却ゾーンにおける冷却水の温度、冷却装置の各冷却ゾーンにおける冷却水の水量密度、厚鋼板の幅方向における冷却水の流量分布、および、冷却装置の前後段冷却比からなる群より選択された一以上が含まれる。また、「冷却装置の前後段冷却比」とは、冷却装置の複数ある冷却ゾーンを、厚鋼板の搬送方向上流側の前段冷却ゾーンと、当該前段冷却ゾーンに隣接する厚鋼板の搬送方向下流側の後段冷却ゾーンとに分けたとき、前段冷却ゾーンに供給される冷却水の水量密度をγ、後段冷却ゾーンに供給される冷却水の水量密度をθとするとき、ＲＦＢ＝γ／θで導かれるＲＦＢをいう。 Here, the “up / down water amount ratio of the cooling device” means that the amount of cooling water supplied to the cooling header arranged on the upper surface side of the thick steel plate cooled by the cooling device is α, the lower surface side of the thick steel plate When the amount of cooling water supplied to the cooling header arranged in [beta] is [beta], it means RTB derived by RTB = [alpha] / [beta]. In addition, in the “other manufacturing conditions”, specifically, the actual value of the surface temperature of the thick steel plate on the inlet side of the cooling device, the actual value of the surface temperature of the thick steel plate on the outlet side of the cooling device, Plate thickness, plate width of steel plate, transport speed of steel plate, temperature of cooling water in each cooling zone of cooling device, water density of cooling water in each cooling zone of cooling device, flow rate of cooling water in width direction of steel plate One or more selected from the group consisting of the distribution and the cooling ratio before and after the cooling device are included. In addition, the “front / rear cooling ratio of the cooling device” means that there are a plurality of cooling zones of the cooling device, the upstream cooling zone on the upstream side in the conveying direction of the thick steel plate, and the downstream side in the conveying direction of the thick steel plate adjacent to the preceding cooling zone When divided into the subsequent cooling zone, the amount of cooling water supplied to the preceding cooling zone is γ, and the amount of cooling water supplied to the subsequent cooling zone is θ, R FB = γ / θ Refers to the RFB that is led.
また、上記本発明の第１の態様において、過去の製造実績に関する情報が保存されている記憶手段から、冷却される厚鋼板の操業条件に近い製造実績に関する情報を抽出し、抽出した製造実績に関する情報と平坦度合格率との関係を求め、求めた関係から上下水量比を決定しても良い。ここに、本発明の第１の態様、および、以下に示す本発明の他の態様において、保存されている過去の製造実績が、冷却される厚鋼板の操業条件に近いか否かは、過去の製造実績の操業条件を表す情報ベクトルと、冷却される厚鋼板の操業条件を表す情報ベクトルとの間の距離関数を定義して、当該距離の大きさに基づいて判断すること
ができる。
Moreover, in the first aspect of the present invention, information related to the manufacturing performance close to the operating conditions of the steel plate to be cooled is extracted from the storage means in which information related to the past manufacturing performance is stored, and the extracted manufacturing performance is related. The relationship between the information and the flatness pass rate may be obtained, and the water / water ratio may be determined from the obtained relationship. Here, in the first aspect of the present invention and the other aspects of the present invention described below, whether or not the stored past production results are close to the operating conditions of the steel plate to be cooled is It is possible to define a distance function between an information vector that represents the operating condition of the actual manufacturing results and an information vector that represents the operating condition of the steel plate to be cooled, and make a determination based on the magnitude of the distance.
また、抽出した製造実績に関する情報と平坦度合格率との関係から上下水量比を決定する上記本発明の第１の態様において、冷却される厚鋼板の操業条件に近い製造実績に関する情報として前後段冷却比を抽出した上で、該前後段冷却比を含む、冷却される厚鋼板の操業条件に近い製造実績に関する情報と、平坦度合格率との関係を求め、求めた関係から上記上下水量比を決定しても良い。 Further, in the first aspect of the present invention in which the ratio of water and sewage is determined from the relationship between the extracted manufacturing performance information and the flatness pass rate, as the information on the manufacturing performance close to the operating conditions of the steel plate to be cooled, After extracting the cooling ratio, the relationship between the production performance close to the operating conditions of the steel plate to be cooled, including the front and rear cooling ratio, and the flatness pass rate are obtained, and the above water and water ratio is calculated from the obtained relationship. May be determined.
本発明の第２の態様は、厚鋼板を仕上圧延する工程と、該仕上圧延する工程の後に厚鋼板を冷却する工程と、を有し、冷却する工程で、上記本発明の第１の態様にかかる厚鋼板の冷却制御方法が適用されることを特徴とする、厚鋼板の製造方法である。 The second aspect of the present invention includes a step of finish rolling the thick steel plate and a step of cooling the thick steel plate after the step of finish rolling, and the step of cooling the first aspect of the present invention. A method for manufacturing a thick steel plate, characterized in that the method for controlling cooling of a thick steel plate according to claim 1 is applied.
本発明の第３の態様は、仕上圧延された厚鋼板を冷却する冷却装置へと供給される冷却水量を制御する冷却制御装置であって、過去の製造実績に関する情報を保存する記憶部と、該記憶部に保存されている過去の製造実績から、冷却される厚鋼板の平坦度合格率が所定値以上になる冷却装置の上下水量比を決定する上下水量比決定部と、決定した上下水量比、および、これ以外の製造条件から、厚鋼板の幅方向における冷却後の予測温度の分布を求める温度分布予測部と、温度分布予測部で求めた冷却後の予測温度の分布幅が一定値以下になる、厚鋼板の幅方向における冷却水の流量分布を決定する流量分布決定部と、上下水量比決定部で決定された上下水量比、および、流量分布決定部で決定された冷却水の流量分布となるように、冷却装置へと供給される冷却水の水量を、厚鋼板の冷却中に変動させるように制御する制御部と、を有する、厚鋼板の冷却制御装置である。 A third aspect of the present invention is a cooling control device that controls the amount of cooling water supplied to a cooling device that cools the finish-rolled thick steel plate, and stores a storage unit that stores information related to past manufacturing results, From the past manufacturing results stored in the storage unit, the water and water ratio determining unit for determining the water and water ratio of the cooling device that has a flatness pass rate of the cooled thick steel plate equal to or higher than a predetermined value, and the determined water and water amount The temperature distribution prediction unit for obtaining the distribution of the predicted temperature after cooling in the width direction of the thick steel plate from the ratio and other manufacturing conditions, and the distribution range of the predicted temperature after cooling obtained by the temperature distribution prediction unit are constant values. The flow rate distribution determining unit that determines the flow rate distribution of the cooling water in the width direction of the thick steel plate, the vertical water amount ratio determined by the vertical water amount ratio determining unit, and the cooling water determined by the flow rate distribution determining unit are as follows: Make sure that the cooling The quantity of cooling water supplied to, and a control unit for controlling to vary during the steel plate cooling, a cooling control apparatus of steel plate.
また、上記本発明の第３の態様において、記憶部から抽出した、冷却される厚鋼板の操業条件に近い製造実績に関する情報と、平坦度合格率との関係を求め、求めた関係を用いて、上下水量比決定部で上下水量比を決定しても良い。 Moreover, in the said 3rd aspect of this invention, the relationship between the information regarding the manufacturing performance close to the operating condition of the steel plate to be cooled, extracted from the storage unit, and the flatness pass rate is obtained, and the obtained relationship is used. The water / water ratio may be determined by the water / water ratio determination unit.
また、抽出した製造実績に関する情報と平坦度合格率との関係を用いて上下水量比を決定する上記本発明の第３の態様において、冷却される厚鋼板の操業条件に近い製造実績に関する情報として前後段冷却比を抽出した上で、該前後段冷却比を含む、冷却される厚鋼板の操業条件に近い製造実績に関する情報と、平坦度合格率との関係を求め、求めた関係を用いて、上記上下水量比決定部で上記上下水量比を決定しても良い。 Moreover, in the 3rd aspect of the said invention which determines the amount-of-water-supply ratio using the relationship between the information regarding the extracted manufacturing performance, and the flatness pass rate, as information regarding the manufacturing performance close to the operating condition of the steel plate to be cooled After extracting the front-rear cooling ratio, obtain the relationship between the production results close to the operating conditions of the steel plate to be cooled, including the front-rear cooling ratio, and the flatness pass rate, and use the obtained relationship The water / water ratio may be determined by the water / water ratio determination unit.
本発明の第４の態様は、厚鋼板を仕上圧延する圧延機と、該圧延機で圧延された厚鋼板を冷却する冷却装置と、該冷却装置の動作を制御する冷却制御装置と、を備え、該冷却制御装置が、上記本発明の第３の態様にかかる厚鋼板の冷却制御装置である、厚鋼板の製造装置である。 A fourth aspect of the present invention includes a rolling mill for finish rolling a thick steel plate, a cooling device for cooling the thick steel plate rolled by the rolling mill, and a cooling control device for controlling the operation of the cooling device. The cooling control device is a thick steel plate manufacturing device, which is the thick steel plate cooling control device according to the third aspect of the present invention.
本発明によれば、厚鋼板の冷却停止温度に関して、冷却装置の設定因子が厚鋼板の幅方向の温度むらに与える影響度合いをモデル化し、そのモデルを用いて幅方向の温度むらが所定値以下となるような設定因子を逆算し、また、板幅中央部の長手方向の温度むらを抑制するために、各冷却ゾーンの水量密度をダイナミック制御し、かつ、冷却後の厚鋼板の平坦度に影響を与える上下水量比の設定に際しては、平坦度良否の過去データベースからその時点で最も平坦度良品率が高くなる上下水量比を求めることが可能になる。そのため、本発明によれば、長手方向および幅方向の温度むらを抑制するとともに、冷却後の厚鋼板の平坦度を高めることが可能な、厚鋼板の冷却制御方法および冷却制御装置並びに厚鋼板の製造方法および製造装置を提供することができる。 According to the present invention, regarding the cooling stop temperature of the thick steel plate, the degree of influence of the setting factor of the cooling device on the temperature unevenness in the width direction of the thick steel plate is modeled, and the temperature unevenness in the width direction is equal to or less than a predetermined value using the model. In order to back-calculate the setting factors such that the temperature density in the longitudinal direction of the central part of the plate width is suppressed, the water density in each cooling zone is dynamically controlled, and the flatness of the thick steel plate after cooling is controlled. When setting the water / water ratio to affect, it is possible to obtain the water / water ratio that gives the highest flatness / non-defective product ratio at that time from the past flatness / defectiveness database. Therefore, according to the present invention, it is possible to suppress the temperature unevenness in the longitudinal direction and the width direction, and to increase the flatness of the thick steel plate after cooling. A manufacturing method and a manufacturing apparatus can be provided.
以下、図面を参照しつつ、本発明の実施の形態について説明する。なお、以下に示す形
態は本発明の例示であり、本発明は以下に示す形態に限定されない。
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the form shown below is an illustration of this invention and this invention is not limited to the form shown below.
図１は、本発明の厚鋼板の冷却制御方法を実施可能であり、且つ、本発明の厚鋼板の製造装置に備えられる、本発明の厚鋼板の冷却制御装置１０を説明する図である。図１には、供給される冷却水量が冷却制御装置１０によって制御される冷却装置２０、および、該冷却装置２０によって冷却される厚鋼板１等も示しており、冷却制御装置１０よりも厚鋼板１の搬送方向上流側には、不図示の圧延機が備えられている。 FIG. 1 is a diagram for explaining a thick steel plate cooling control apparatus 10 according to the present invention, which can implement the thick steel sheet cooling control method according to the present invention and is provided in the thick steel plate manufacturing apparatus of the present invention. FIG. 1 also shows a cooling device 20 in which the amount of supplied cooling water is controlled by the cooling control device 10, a thick steel plate 1 cooled by the cooling device 20, and the like. A rolling mill (not shown) is provided on the upstream side of 1 in the conveying direction.
冷却制御装置１０は、記憶部１１と、上下水量比決定部１２と、トラッキング部１３と、厚鋼板移動速度予測部１４と、冷却ゾーン通過所要時間計算部１５と、現在温度計算部１６と、温度分布予測部１７と、流量分布決定部１８と、制御部１９と、を有している。 The cooling control device 10 includes a storage unit 11, a water amount ratio determination unit 12, a tracking unit 13, a steel plate moving speed prediction unit 14, a cooling zone passage required time calculation unit 15, a current temperature calculation unit 16, A temperature distribution prediction unit 17, a flow rate distribution determination unit 18, and a control unit 19 are included.
記憶部１１には、厚鋼板の過去の製造実績に関する情報が記憶されており、この過去の製造実績に関する情報を用いて、上下水量比決定部１２で、厚鋼板１の平坦度合格率が所定値以上になる冷却装置２０の上下水量比が決定される。 The storage unit 11 stores information related to past production results of thick steel plates, and the flatness pass rate of the thick steel plate 1 is predetermined by the water / water ratio determination unit 12 using information related to the past production results. The water / water ratio of the cooling device 20 that is equal to or greater than the value is determined.
トラッキング部１３は、厚鋼板１の先端から長手方向（厚鋼板１の長さ方向。図１の紙面右側（先端側）から左側（尾端側）の方向。）に一定の間隔で設けられた仮想的な制御点（Ｐ１〜Ｐｎ）の位置をトラッキングする。具体的には、ソフトウエアにより、トラッキング処理が行われる。 The tracking unit 13 is provided at regular intervals from the front end of the thick steel plate 1 in the longitudinal direction (the length direction of the thick steel plate 1; the direction from the right side (front end side) to the left side (tail end side) in FIG. The positions of virtual control points (P 1 to P n ) are tracked. Specifically, tracking processing is performed by software.
冷却装置２０の入側における厚鋼板１の温度は、温度計２によって測定され、冷却装置２０の出側における厚鋼板１の温度は、温度計３によって測定される。温度計２、３としては、放射温度計を用いることができる。放射温度計を用いる場合、板幅中央部の温度を測定すれば良い。温度計２、３としては、板幅方向の温度分布を測定可能な走査式の幅温度計を用いることも可能である。なお、図１では温度計２，３は厚鋼板の上面を測温する形態となっているが、下面を測温する形態でもよい。 The temperature of the thick steel plate 1 on the entry side of the cooling device 20 is measured by the thermometer 2, and the temperature of the thick steel plate 1 on the exit side of the cooling device 20 is measured by the thermometer 3. A radiation thermometer can be used as the thermometers 2 and 3. When using a radiation thermometer, the temperature at the center of the plate width may be measured. As the thermometers 2 and 3, a scanning width thermometer capable of measuring the temperature distribution in the plate width direction may be used. In FIG. 1, the thermometers 2 and 3 are configured to measure the upper surface of the thick steel plate, but may be configured to measure the lower surface.
厚鋼板移動速度予測部１４は、トラッキング部１３からの制御点の位置情報を受け取り、厚鋼板１の移動速度を予測する手段である。具体的には、冷却前に厚鋼板１の製造条件（冷却開始温度、冷却速度、冷却停止温度等）に基づいて予め速度パターンを決定した上で、このパターンに基づいて速度予測を行う。 The steel plate moving speed prediction unit 14 is means for receiving the position information of the control points from the tracking unit 13 and predicting the moving speed of the steel plate 1. Specifically, a speed pattern is determined in advance based on the manufacturing conditions (cooling start temperature, cooling speed, cooling stop temperature, etc.) of the thick steel plate 1 before cooling, and speed prediction is performed based on this pattern.
冷却ゾーン通過所要時間計算部１５は、厚鋼板移動速度予測部１４からの予測速度情報を受け取り、冷却装置２０の各冷却ゾーン（Ａ、Ｂ、Ｃ、Ｄ）を厚鋼板１が通過するのに必要な時間を計算する。この時間は、各冷却ゾーンの距離と予測した厚鋼板の移動速度とから得ることができる。 The cooling zone passage required time calculation unit 15 receives the predicted speed information from the thick steel plate moving speed prediction unit 14, and the thick steel plate 1 passes through each cooling zone (A, B, C, D) of the cooling device 20. Calculate the time required. This time can be obtained from the distance between the cooling zones and the predicted moving speed of the thick steel plate.
現在温度計算部１６は、トラッキング部１３からの制御点の位置情報、および、温度計２からの温度情報から、冷却装置２０の入口部に先行した制御点の現時点における温度を計算する。具体的には、各制御点における水冷熱伝達モデルによる熱伝達率の計算、および、該熱伝達率を用いた各制御点における現在温度の計算が行われる。 The current temperature calculation unit 16 calculates the current temperature of the control point preceding the inlet of the cooling device 20 from the position information of the control point from the tracking unit 13 and the temperature information from the thermometer 2. Specifically, the heat transfer coefficient is calculated by a water-cooled heat transfer model at each control point, and the current temperature at each control point is calculated using the heat transfer coefficient.
温度分布予測部１７は、上下水量比決定部１２で決定された上下水量比、および、これ以外の製造条件から、厚鋼板１の幅方向における冷却後の予測温度の分布を求める。「これ以外の製造条件」には、温度計２によって測定された厚鋼板１の表面温度の実績値、厚鋼板１の板厚、厚鋼板１の板幅、厚鋼板１の板長、厚鋼板１の搬送速度（移動速度）、冷却装置２０の各冷却ゾーンにおける冷却水の温度、冷却装置２０の各冷却ゾーンにおける冷却水の水量密度、および、厚鋼板１の幅方向における冷却水の流量分布、からなる群より選択された一以上が含まれる。温度分布予測部１７における温度の計算方法は、現在温
度計算部１６における計算方法と同様である。
The temperature distribution predicting unit 17 obtains the predicted temperature distribution after cooling in the width direction of the thick steel plate 1 from the water / water ratio determined by the water / water ratio determining unit 12 and other manufacturing conditions. “Other manufacturing conditions” include actual values of the surface temperature of the thick steel plate 1 measured by the thermometer 2, the plate thickness of the thick steel plate 1, the plate width of the thick steel plate 1, the plate length of the thick steel plate 1, and the thick steel plate. 1 conveyance speed (movement speed), the temperature of the cooling water in each cooling zone of the cooling device 20, the amount of cooling water in each cooling zone of the cooling device 20, and the flow rate distribution of the cooling water in the width direction of the steel plate 1 , One or more selected from the group consisting of: The temperature calculation method in the temperature distribution prediction unit 17 is the same as the calculation method in the current temperature calculation unit 16.
流量分布決定部１８は、厚鋼板１の冷却後の予測温度、および、目標温度情報に基づいて、温度分布予測部１７で求めた冷却後の予測温度の分布幅が一定値以下になる、厚鋼板１の幅方向における冷却水の流量分布を決定する。温度分布予測部１７で幅方向における冷却後の温度分布を予測計算する際には、幅方向の温度むらを低減する制御が反映されていないため、幅方向の温度むらが生じてしまう。そこで、幅方向の温度むらを低減するために、流量分布決定部１８で、幅方向における冷却水の流量分布を決定する。具体的には、冷却水の流量分布を変えた２つの幅方向温度分布を、温度分布予測部１７から得て、これらについて収束計算を行うことで、幅方向の温度むらが最小になる冷却水の流量分布を決定することができる。 The flow rate distribution determining unit 18 is configured such that, based on the predicted temperature after cooling of the thick steel plate 1 and the target temperature information, the distribution width of the predicted temperature after cooling obtained by the temperature distribution predicting unit 17 is equal to or less than a certain value. The flow rate distribution of the cooling water in the width direction of the steel plate 1 is determined. When the temperature distribution prediction unit 17 predicts and calculates the temperature distribution after cooling in the width direction, control for reducing the temperature unevenness in the width direction is not reflected, and thus temperature unevenness in the width direction occurs. Therefore, in order to reduce the temperature unevenness in the width direction, the flow rate distribution determination unit 18 determines the flow rate distribution of the cooling water in the width direction. Specifically, two temperature distributions in the width direction in which the flow rate distribution of the cooling water is changed are obtained from the temperature distribution predicting unit 17, and the convergence calculation is performed on these to thereby minimize the temperature unevenness in the width direction. The flow rate distribution can be determined.
制御部１９は、上下水量比決定部１２で決定された上下水量比、および、流量分布決定部１８で決定された冷却水の流量分布となるように、冷却装置２０へと供給される冷却水の水量を制御する。具体的には、冷却装置２０へと供給される冷却水が流れる配管に設置されたバルブの動作を制御することにより行われる。 The control unit 19 supplies the cooling water supplied to the cooling device 20 so that the water / water flow ratio determined by the water / water ratio determination unit 12 and the cooling water flow distribution determined by the flow distribution determination unit 18 are obtained. Control the amount of water. Specifically, it is performed by controlling the operation of a valve installed in a pipe through which the cooling water supplied to the cooling device 20 flows.
図２は、本発明の厚鋼板の冷却制御方法を説明する図である。図１および図２を参照しつつ、本発明の厚鋼板の冷却制御方法について説明する。なお、ここでは、冷却制御装置１０を用いて制御する形態について説明するが、本発明の厚鋼板の冷却制御方法は、同様に冷却することができれば、その形態はこれに限定されない。
図２に示したように、本発明の厚鋼板の冷却制御方法は、冷却装置の上下水量比を決定する工程Ｓ１１と、厚鋼板の幅方向における冷却後の温度分布を予測する工程Ｓ１２と、当該工程Ｓ１２で予測した冷却後の温度分布の幅が一定値以下になる厚鋼板の幅方向における冷却水の流量分布を決定する工程Ｓ１３と、工程Ｓ１１で決定された上下水量比、および、工程Ｓ１３で決定された冷却水の流量分布となるように、冷却装置へと供給される冷却水の水量を、厚鋼板の冷却中に変動させるように制御する工程Ｓ１４と、を有している。工程Ｓ１１は上下水量比決定部１２で行われ、工程Ｓ１２は温度分布予測部１７で行われ、工程Ｓ１３は流量分布決定部１８で行われ、工程Ｓ１４は制御部１９で行われる。
FIG. 2 is a diagram for explaining a cooling control method for a thick steel plate according to the present invention. With reference to FIG. 1 and FIG. 2, the cooling control method of the thick steel plate of this invention is demonstrated. In addition, although the form controlled using the cooling control apparatus 10 is demonstrated here, if the cooling control method of the thick steel plate of this invention can be cooled similarly, the form will not be limited to this.
As shown in FIG. 2, the cooling control method for a thick steel plate according to the present invention includes a step S11 for determining a water / water ratio of the cooling device, a step S12 for predicting a temperature distribution after cooling in the width direction of the thick steel plate, Step S13 for determining the flow rate distribution of the cooling water in the width direction of the thick steel plate in which the width of the temperature distribution after cooling predicted in Step S12 is equal to or less than a certain value, the ratio of the amount of water and water determined in Step S11, and the step And a step S14 for controlling the amount of cooling water supplied to the cooling device to vary during cooling of the thick steel plate so that the flow rate distribution of cooling water determined in S13 is obtained. Step S11 is performed by the water / water ratio ratio determination unit 12, step S12 is performed by the temperature distribution prediction unit 17, step S13 is performed by the flow rate distribution determination unit 18, and step S14 is performed by the control unit 19.
＜長手方向温度分布改善＞
仕上圧延された厚鋼板１は、冷却装置２０において水冷され、所望の水冷停止温度まで冷却される。この際、冷却装置２０の入側に設置されている温度計２によって、厚鋼板１の上表面温度が測定される。図１に示した形態では、仮想的な制御点（Ｐ１〜Ｐｎ）を厚鋼板１の先端から一定の距離間隔で当該の厚鋼板１上に設けており、仮想的な制御点の初期温度は、温度計２で測定した温度とする。なお、図１では、Ｐ１が厚鋼板の最先端より内側にある形態となっているが、Ｐ１を厚鋼板の最先端にとっても良い。
<Improvement of longitudinal temperature distribution>
The finish-rolled thick steel plate 1 is water cooled in the cooling device 20 and cooled to a desired water cooling stop temperature. At this time, the upper surface temperature of the thick steel plate 1 is measured by the thermometer 2 installed on the entry side of the cooling device 20. In the form shown in FIG. 1, virtual control points (P 1 to P n ) are provided on the thick steel plate 1 at a certain distance from the tip of the thick steel plate 1, and the initial virtual control points are set. The temperature is the temperature measured with the thermometer 2. In FIG. 1, P 1 is on the inner side of the leading edge of the thick steel plate, but P 1 may be on the leading edge of the thick steel plate.
冷却装置２０へと供給される冷却水量を制御する際には、仮想的な制御点について、冷却装置２０内の位置およびその制御点の温度をトラッキングする。現時点（時刻ｔとする）での制御点の位置は、時刻ｔまでの厚鋼板１の搬送速度の実績から求めることができ、時刻ｔよりも後の制御点の位置は、搬送速度の予測値を用いて予測する。同様に、現時点（時刻ｔ）での制御点の温度は、冷却装置２０内における時刻ｔまでの水冷実績に基づいて計算され、冷却装置２０の出口における厚鋼板１の温度（以下において、「出口温度」ということがある。）は、冷却装置２０の各冷却ゾーンの通過所要時間を予測する計算の結果と、現時点での制御点の温度とから、鋼板温度計算モデルに基づいて予測する。 When controlling the amount of cooling water supplied to the cooling device 20, the position in the cooling device 20 and the temperature of the control point are tracked with respect to virtual control points. The position of the control point at the present time (referred to as time t) can be obtained from the record of the conveyance speed of the steel plate 1 up to time t, and the position of the control point after time t is the predicted value of the conveyance speed. To predict. Similarly, the temperature of the control point at the present time (time t) is calculated based on the water cooling performance up to time t in the cooling device 20, and the temperature of the thick steel plate 1 at the outlet of the cooling device 20 (hereinafter referred to as “outlet”). The temperature is sometimes referred to as “temperature”.) Is predicted based on the steel plate temperature calculation model from the calculation result for predicting the time required to pass through each cooling zone of the cooling device 20 and the temperature of the control point at the present time.
このようにして算出された出口温度の予測値と目標温度である水冷停止温度とが一致するように、冷却装置２０へと供給される冷却水の最適水量を求め、冷却装置２０の冷却ゾーン毎に流量指令を出す。この流量指令の制御は、冷却装置２０の入側に配置された温度計２の直下で制御点を一定間隔で生成し、この制御点をトラッキングしながら、制御点の出口温度が目標温度となるように、冷却装置２０へと供給される冷却水の水量をダイナミックに設定する（厚鋼板１の冷却中に冷却水の水量を変動させる）ので、ダイナミック制御と呼ぶ。 The optimum amount of cooling water supplied to the cooling device 20 is determined so that the predicted value of the outlet temperature calculated in this way matches the water cooling stop temperature that is the target temperature, and each cooling zone of the cooling device 20 is determined. A flow rate command is issued. In the control of the flow rate command, control points are generated at regular intervals directly below the thermometer 2 arranged on the entry side of the cooling device 20, and the outlet temperature of the control point becomes the target temperature while tracking the control points. As described above, the amount of cooling water supplied to the cooling device 20 is dynamically set (the amount of cooling water is varied during the cooling of the thick steel plate 1), and is therefore referred to as dynamic control.
図３は、ダイナミック制御を実施した際の、厚鋼板１の各制御点の温度変化を示す図である。図３に示したように、冷却装置２０の入口では高温だった厚鋼板１は、その先端（Ｐ１側）から、冷却装置２０の出口で目標温度になるように冷却されて、鋼板温度が低下する。 FIG. 3 is a diagram illustrating a temperature change at each control point of the thick steel plate 1 when the dynamic control is performed. As shown in FIG. 3, the thick steel plate 1 that was hot at the inlet of the cooling device 20 is cooled from its front end (P1 side) to the target temperature at the outlet of the cooling device 20, and the steel plate temperature decreases. To do.
図４に、ダイナミック制御を行った場合と、ダイナミック制御を行わずに予め与えられた厚鋼板１の冷却条件から冷却装置２０による水冷条件を事前に決定して制御した場合との比較を示す。図４は、冷却装置２０の入口における温度変動を±１５℃、変動ピッチを１０ｍとして、数値実験にて求めた冷却装置２０の出口における長手方向温度変動（長手方向の温度むら）を比較した図である。図４（ａ）の縦軸は冷却装置２０の出口における厚鋼板１の表面温度、横軸は厚鋼板の位置［ｍ］であり、図４（ｂ）の縦軸は、ダイナミック制御を実施した場合の温度変動とダイナミック制御を実施しない場合の温度変動との比、横軸は外乱周波数［Ｈｚ］である。図４（ａ）および図４（ｂ）に示したように、ダイナミック制御を実施した場合には、温度変動を半分に抑制することができる。 FIG. 4 shows a comparison between the case where the dynamic control is performed and the case where the water cooling condition by the cooling device 20 is determined in advance from the cooling condition of the thick steel plate 1 given in advance without performing the dynamic control. FIG. 4 is a graph comparing longitudinal temperature fluctuations (longitudinal temperature unevenness) at the outlet of the cooling device 20 obtained by numerical experiments with a temperature fluctuation of ± 15 ° C. and a fluctuation pitch of 10 m at the inlet of the cooling device 20. It is. The vertical axis in FIG. 4A is the surface temperature of the thick steel plate 1 at the outlet of the cooling device 20, the horizontal axis is the position [m] of the thick steel plate, and the vertical axis in FIG. The ratio between the temperature fluctuation in this case and the temperature fluctuation in the case where dynamic control is not performed, the horizontal axis is the disturbance frequency [Hz]. As shown in FIGS. 4A and 4B, when dynamic control is performed, temperature fluctuations can be suppressed to half.
冷却装置２０は、厚鋼板１の上面側に配置された上面ヘッダー群２１、および、厚鋼板１の下面側に配置された下面ヘッダー群２２を有しており、冷却装置２０へと供給された冷却水は、上面ヘッダー群２１および下面ヘッダー群２２へと配分される。このときの配分は、上下水量比ＲＴＢ（＝上面ヘッダー群２１へと供給される冷却水の水量α／下面ヘッダー群２２へと供給される冷却水の水量β）に基づいて決定される。 The cooling device 20 has an upper surface header group 21 disposed on the upper surface side of the thick steel plate 1 and a lower surface header group 22 disposed on the lower surface side of the thick steel plate 1 and is supplied to the cooling device 20. The cooling water is distributed to the upper header group 21 and the lower header group 22. The distribution at this time is determined based on the upper and lower water amount ratio R TB (= water amount α of cooling water supplied to the upper surface header group 21 / water amount β of cooling water supplied to the lower surface header group 22).
上面ヘッダー群２１は、製造ラインの進行方向に複数の冷却ゾーンＡ、Ｂ、Ｃ、Ｄに分かれ、さらに各冷却ゾーンＡ、Ｂ、Ｃ、Ｄには、複数の上面ヘッダー２１ａ、２１ａ、…が厚鋼板１の進行方向に並列されている。図５は、上面ヘッダー２１ａを下方（厚鋼板１側）から見た図である。図５では、水が流れる方向を矢印で示している。 The upper surface header group 21 is divided into a plurality of cooling zones A, B, C, and D in the traveling direction of the production line, and each of the cooling zones A, B, C, and D has a plurality of upper surface headers 21a, 21a,. Parallel to the traveling direction of the thick steel plate 1. FIG. 5 is a view of the top header 21a as viewed from below (from the thick steel plate 1 side). In FIG. 5, the direction in which water flows is indicated by arrows.
上面ヘッダー２１ａは、図５に示したように、厚鋼板１の板幅方向（図１の紙面奥／手前方向）に長く形成された横断面が矩形（大径）の管状部材であり、その下面にはノズル２１ｂ、２１ｂ、…が配置されている。また、上面ヘッダー２１ａの内側には仕切り板２１ｃ、２１ｃが設けられ、仕切られた各部位に枝給水管２１ｄ、２１ｄ、２１ｄが接続されている。枝給水管２１ｄ、２１ｄ、２１ｄへの水量の調整をバルブ２１ｅによって行うことにより、図５のグラフに示したように、厚鋼板１の幅方向の冷却水の流量分布を調整可能なように構成されている。 As shown in FIG. 5, the upper surface header 21 a is a tubular member having a rectangular (large diameter) cross section formed long in the plate width direction of the thick steel plate 1 (backward / frontward direction in FIG. 1). Nozzles 21b, 21b,... Are arranged on the lower surface. Moreover, the partition plates 21c and 21c are provided inside the upper surface header 21a, and branch water supply pipes 21d, 21d, and 21d are connected to the partitioned portions. The flow rate distribution of the cooling water in the width direction of the thick steel plate 1 can be adjusted as shown in the graph of FIG. 5 by adjusting the amount of water to the branch water supply pipes 21d, 21d, 21d by the valve 21e. Has been.
一方、下面ヘッダー群２２も、上面ヘッダー群２１と同様に、厚鋼板１の進行方向に複数の冷却ゾーンＡ、Ｂ、Ｃ、Ｄに分かれ、さらに各冷却ゾーンＡ、Ｂ、Ｃ、Ｄには、複数の下面ヘッダー２２ａ、２２ａ、…が厚鋼板１の進行方向に並列されている。ここで、厚鋼板１の下面は、上面ほど幅方向の温度むらが大きくない。そのため、下面ヘッダー群２２には、基本的に上面ヘッダー群２１のような冷却水の流量分布を調整する機能を付加しなくても良い。 On the other hand, the lower surface header group 22 is also divided into a plurality of cooling zones A, B, C, and D in the traveling direction of the thick steel plate 1, as in the upper surface header group 21. A plurality of lower surface headers 22 a, 22 a,... Are arranged in parallel in the traveling direction of the thick steel plate 1. Here, the lower surface of the thick steel plate 1 is not as uneven in temperature in the width direction as the upper surface. Therefore, it is not necessary to add the function of adjusting the flow rate distribution of the cooling water to the lower surface header group 22 basically like the upper surface header group 21.
＜幅方向温度分布改善＞
上記のダイナミック制御により、厚鋼板１の長手方向の温度むらを抑制することが可能になるが、温度むらには幅方向の温度むらも存在する。そのため、厚鋼板１の全長および全幅に亘る温度の均一性を確保するには、厚鋼板１の幅方向の温度むらも抑制する必要がある。そこで、冷却装置２０は、図５にも示したように、幅方向の冷却水の流量分布を調整可能なように構成された上面ヘッダー群２１が備えられる形態としている。このような形態とすることにより、冷却装置２０から厚鋼板１へ向けて供給された冷却水の、厚鋼板１の幅方向における流量分布（流量クラウン量）を適切に設定することが可能になり、これによって、幅方向の温度むらが所定値以下となるように制御することが可能になる。
<Improve width direction temperature distribution>
Although the temperature control in the longitudinal direction of the thick steel plate 1 can be suppressed by the above dynamic control, the temperature unevenness also includes temperature unevenness in the width direction. Therefore, in order to ensure the uniformity of the temperature over the entire length and the entire width of the thick steel plate 1, it is necessary to suppress the temperature unevenness in the width direction of the thick steel plate 1. Therefore, as shown in FIG. 5, the cooling device 20 is configured to include an upper surface header group 21 configured to be able to adjust the flow rate distribution of the cooling water in the width direction. By setting it as such a form, it becomes possible to set appropriately the flow distribution (flow crown amount) in the width direction of the thick steel plate 1 of the cooling water supplied toward the thick steel plate 1 from the cooling device 20. Thus, it becomes possible to control the temperature unevenness in the width direction to be a predetermined value or less.
厚鋼板１の幅方向中央部の温度は、下記式（１）に示す板厚方向１次元熱伝導方程式により表すことができる。 The temperature at the center in the width direction of the thick steel plate 1 can be expressed by a one-dimensional heat conduction equation in the plate thickness direction shown in the following formula (1).
厚鋼板１の上表面および下表面における境界条件は、下記式（２）（３）により与える。 The boundary conditions on the upper surface and the lower surface of the thick steel plate 1 are given by the following formulas (2) and (3).
ここで、Ｔは温度［℃］、ｔは時間［ｓ］、ｘは板厚方向の座標［ｍ］、ｃは比熱［Ｊ／ｋｇ・ｓ］、ρは密度［ｋｇ／ｍ３］、λは熱伝導率［Ｗ／ｍ・℃］、ｑｗは水冷による熱流束［Ｗ／ｍ２］、ｑｅは対流による熱流束［Ｗ／ｍ２］、ｑｒは輻射による熱流束［Ｗ／ｍ２］を表し、ｕは上面を表す添字、ｄは下面を表す添字である。 Here, T is the temperature [° C.], t is the time [s], x is the coordinate [m] in the thickness direction, c is the specific heat [J / kg · s], ρ is the density [kg / m 3 ], λ Is the thermal conductivity [W / m · ° C.], q w is the heat flux [W / m 2 ] by water cooling, q e is the heat flux [W / m 2 ] by convection, and q r is the heat flux [W / m 2 by radiation. m 2 ], u is a subscript representing the upper surface, and d is a subscript representing the lower surface.
水冷による熱流束ｑｗ、および、対流による熱流束ｑｅは、それぞれ、熱伝達率を用いて以下のように書くことができる。 The heat flux q w by water cooling and the heat flux q e by convection can be written as follows using the heat transfer coefficient.
ここで、Ｔｓは厚鋼板１の表面温度［℃］、Ｔｗは冷却水の温度［℃］、Ｔａは雰囲気の温度［℃］であり、Ｈｗは水冷熱伝達率、Ｈａは対流熱伝達率である。 Here, T s is the surface temperature of the steel plate 1 [° C.], T w is the temperature of the cooling water [° C.], Ta is the temperature of the atmosphere [° C.], H w is the water cooling heat transfer coefficient, and H a is Convective heat transfer coefficient.
また、輻射による熱流束ｑｒは、放射率εとステファン・ボルツマン定数σとを用いて以下にように書くことができる。 The heat flux qr due to radiation can be written as follows using the emissivity ε and the Stefan-Boltzmann constant σ.
上記の式（１）を、各冷却ゾーンでの水冷条件を反映した境界条件の式（２）〜（６）の下で、有限差分法を用いて、オンラインで解くことにより、厚鋼板１の制御点に対する
温度を計算することができる。
By solving the above equation (1) online using the finite difference method under the boundary condition equations (2) to (6) reflecting the water cooling conditions in each cooling zone, The temperature for the control point can be calculated.
ここで、水冷の熱伝達率Ｈｗは、下記式（７）に示されるように、冷却装置２０の水冷条件である各因子（冷却水の流量Ｗ、厚鋼板１の移動速度Ｖ、冷却水の水温Ｔｗ、厚鋼板１の表面温度Ｔｓ、冷却水の粘性係数μ等）の複雑な関数となっている。 Here, the water-cooling heat transfer coefficient H w is expressed by the following factors (water flow conditions W, moving speed V of the steel plate 1, cooling water, cooling water), as shown in the following formula (7). Water temperature T w , surface temperature T s of thick steel plate 1, viscosity coefficient μ of cooling water, etc.).
厚鋼板の水冷に際しては、鋼板上面での水冷状態が幅方向で異なる。例えば、幅方向の滞留水（板上水）の高さや滞留水（板上水）の幅方向流速が異なっているので、幅方向に温度むらが発生する。そこで、図６に示すように、幅方向冷却特性モデルを用いて、幅方向温度むらを予測し、予測した温度むらが所定の値以下となるように、幅方向の流量クラウン量の設定値を求める。 When water-cooling a thick steel plate, the water-cooled state on the upper surface of the steel plate differs in the width direction. For example, since the height of the stagnant water in the width direction (board water) and the width direction flow velocity of the stagnant water (plate water) are different, temperature unevenness occurs in the width direction. Accordingly, as shown in FIG. 6, the width direction cooling characteristic model is used to predict the width direction temperature unevenness, and the set value of the flow direction crown amount in the width direction is set so that the predicted temperature unevenness becomes a predetermined value or less. Ask.
図６に示したモデルでは、上面ヘッダーおよび下面ヘッダー（以下において、「上下ヘッダー」という。）に挟まれた厚鋼板１の部位の熱伝達率を計算する際に、１組の上下ノズル（上面ヘッダーに配置されたノズルおよび下面ヘッダーに配置されたノズル）の噴流方向を中心に厚鋼板上の領域を同心円状のセルに分割している。このような同心円状のセルに分割したモデルを用いるのは、ノズルから噴出された冷却水は同心円状に厚鋼板上に広がるためである。同心円状に分割したセルは、その分割幅が狭いほど精度の高い予測が可能になるが、計算負荷が大きくなるため、一定の幅を持ったセルに分割すれば良い。より具体的には、並列されるノズル間の距離を考慮して、各ノズルにおけるモデル同士が一部重複する形で形成されるように、モデルの最大半径（モデルで想定するセルの最大半径）を決定し、このモデルを５つ程度のセルに分割すれば良い。図６に示した例では、並列されるノズル間の距離が５０ｍｍであったため、最大半径２５．７ｍｍのモデルを形成した。ここで、各セルは、５．７ｍｍの幅を持つ４つのリング状セルと、中心に半径２．９ｍｍの１つの円状セルと、に分割した。 In the model shown in FIG. 6, when calculating the heat transfer coefficient of the portion of the thick steel plate 1 sandwiched between the upper header and the lower header (hereinafter referred to as “upper and lower header”), The region on the thick steel plate is divided into concentric cells around the jet direction of the nozzle arranged in the header and the nozzle arranged in the lower header. The reason why the model divided into the concentric cells is used is that the cooling water ejected from the nozzle spreads concentrically on the thick steel plate. A cell divided into concentric circles can be predicted with higher accuracy as the division width becomes narrower. However, since the calculation load increases, the cell may be divided into cells having a certain width. More specifically, the maximum radius of the model (the maximum radius of the cell assumed by the model) so that the models at each nozzle partially overlap each other in consideration of the distance between the nozzles arranged in parallel. And the model may be divided into about five cells. In the example shown in FIG. 6, since the distance between the nozzles arranged in parallel is 50 mm, a model having a maximum radius of 25.7 mm was formed. Here, each cell was divided into four ring-shaped cells having a width of 5.7 mm and one circular cell having a radius of 2.9 mm at the center.
このようにして複数のセルに分割したら、セルごとに熱伝達率を算出する。熱伝達率を算出する際には、まず、各セルの水温を計算する。ノズル直下から離れるほど厚鋼板の温度の影響を受けて水温は上昇する。水温は、熱伝達計算で容易に求めることができる。
続いて、セルごとに核沸騰と膜沸騰との割合を求める。沸騰熱伝達現象は、膜沸騰の状態では熱伝達率が小さく、核沸騰の状態では熱伝達率が大きい。厚鋼板の温度が高いときは膜沸騰が主体であるが、低温になると核沸騰に遷移し、熱伝達率が急増する傾向がある。よって、この割合によって、熱伝達率が大きく異なる。極大熱流束点（核沸騰が起こる最高温度）と、極小熱流束点（膜沸騰が起こる最低温度）との関係は実験的に求めることができることが知られている。当該最高温度と当該最低温度との間の温度域は、核沸騰と膜沸騰とが同時に起こる遷移沸騰域と呼ばれる。厚鋼板の表面温度が、核沸騰が起こる最高温度以下であれば、核沸騰の割合が１００％、膜沸騰が起こる最低温度以上であれば膜沸騰の割合が１００％である。従って、厚鋼板の表面温度が遷移沸騰域にあれば、その割合に応じて核沸騰割合（膜沸騰割合）を決める。例えば、水温４０℃の時の当該最高温度が３５０℃、当該最低温度が６００℃であり、且つ、厚鋼板の表面温度が５００℃の場合、核沸騰割合は６０％（膜沸騰割合は４０％）である。この割合は計算により算出しても良いが、予めテーブルを作成し、そのテーブルを参照して割合を決定しても良い。
After dividing into a plurality of cells in this way, the heat transfer coefficient is calculated for each cell. When calculating the heat transfer coefficient, first, the water temperature of each cell is calculated. The water temperature rises under the influence of the temperature of the thick steel plate as it moves away from just below the nozzle. The water temperature can be easily obtained by heat transfer calculation.
Subsequently, the ratio of nucleate boiling and film boiling is determined for each cell. The boiling heat transfer phenomenon has a small heat transfer coefficient in the film boiling state and a large heat transfer coefficient in the nucleate boiling state. When the temperature of the thick steel plate is high, film boiling is the main component, but when the temperature is low, transition to nucleate boiling tends to cause a rapid increase in the heat transfer coefficient. Therefore, the heat transfer coefficient varies greatly depending on this ratio. It is known that the relationship between the maximum heat flux point (maximum temperature at which nucleate boiling occurs) and the minimum heat flux point (minimum temperature at which film boiling occurs) can be obtained experimentally. The temperature range between the maximum temperature and the minimum temperature is called a transition boiling range where nucleate boiling and film boiling occur simultaneously. If the surface temperature of the thick steel plate is below the maximum temperature at which nucleate boiling occurs, the ratio of nucleate boiling is 100%, and if it is above the minimum temperature at which film boiling occurs, the ratio of film boiling is 100%. Therefore, if the surface temperature of the thick steel plate is in the transition boiling region, the nucleate boiling ratio (film boiling ratio) is determined according to the ratio. For example, when the water temperature is 40 ° C., the maximum temperature is 350 ° C., the minimum temperature is 600 ° C., and the surface temperature of the thick steel plate is 500 ° C., the nucleate boiling rate is 60% (the film boiling rate is 40% ). This ratio may be calculated, or a table may be created in advance and the ratio may be determined with reference to the table.
そして、この割合を用いてセルごとに熱伝達率を算出する。算出は核沸騰の場合の熱伝
達率Ｈｎ、および、膜沸騰の場合の熱伝達率Ｈｆをそれぞれ計算し、その割合から各セルの熱伝達率Ｈを算出する。より具体的には、核沸騰、膜沸騰それぞれの場合の熱伝達率は下記式（８）、（９）で計算されるので、これらに沸騰状態の割合を加味し、式（１０）により熱伝達率Ｈを算出する。
Then, the heat transfer coefficient is calculated for each cell using this ratio. The calculation calculates the heat transfer coefficient H n in the case of nucleate boiling and the heat transfer coefficient H f in the case of film boiling, and calculates the heat transfer coefficient H of each cell from the ratio. More specifically, since the heat transfer coefficient in each of nucleate boiling and film boiling is calculated by the following formulas (8) and (9), the ratio of the boiling state is added to these, and the heat transfer coefficient is calculated by formula (10). A transmission rate H is calculated.
ここで、Ｎｕｎは核沸騰ヌッセルト数、Ｎｕｆは膜沸騰ヌッセルト数、λｗは水の熱伝導率［Ｗ／ｍ・℃］、Ｌは代表長さ［ｍ］、ΔＴｓａｔは過熱度［℃］、ΔＴｓｕｂはサブクール度［℃］、Ｔｓは鋼板の表面温度［℃］、Ｔｗは噴流水温［℃］、Ｂは核沸騰割合（０≦Ｂ≦１）をそれぞれ表す。 Here, Nu n is the nucleate boiling Nusselt number, Nu f is the film boiling Nusselt number, λ w is the thermal conductivity of water [W / m · ° C.], L is the representative length [m], and ΔT sat is the superheat degree [ [° C.], ΔT sub is the degree of subcooling [° C.], T s is the surface temperature of the steel sheet [° C.], T w is the jet water temperature [° C.], and B is the nucleate boiling rate (0 ≦ B ≦ 1).
最終的にセルごとに算出した熱伝達率Ｈについて平均値（平均熱伝達率）を計算し、これを上下ヘッダーに挟まれた厚鋼板１の部位の熱伝達率とする。ここで、平均値の計算は単純平均でもよいが、より正確な予測をするためにセルの幅を考慮して積分した平均値を取ることが好ましい。 Finally, an average value (average heat transfer coefficient) is calculated for the heat transfer coefficient H calculated for each cell, and this is used as the heat transfer coefficient of the portion of the thick steel plate 1 sandwiched between the upper and lower headers. Here, the calculation of the average value may be a simple average, but it is preferable to take an average value integrated in consideration of the cell width in order to make a more accurate prediction.
以上、１つのノズルのモデルに関して説明したが、すべてのノズルは同じように計算式により計算される。噴射される冷却水の水量密度が同じであれば、計算値を流用できるが、冷却水の水量密度が異なれば別途計算が必要になる。例えば、冷却水の幅方向流量分布の形状をクラウン状にする（厚鋼板の幅方向に冷却水の流量分布を設ける）場合には、厚鋼板の幅方向両端と中央部とでは水量密度が異なるので、当該水量密度にあわせた計算が必要である。 Although one nozzle model has been described above, all nozzles are calculated by the same calculation formula. If the water density of the injected cooling water is the same, the calculated value can be used, but if the water density of the cooling water is different, a separate calculation is required. For example, when the shape of the flow rate distribution of the cooling water in the width direction is made into a crown shape (the flow rate distribution of the cooling water is provided in the width direction of the thick steel plate), the water density is different at both ends in the width direction and the central portion of the thick steel plate. Therefore, calculation according to the water density is necessary.
一方、隣接する上下ヘッダー間に該当する厚鋼板の部位では、厚鋼板の板幅方向の位置における冷却水流速を加味して熱伝達率を計算する。例えば、厚鋼板の中央部を基準として幅方向にｘ軸を取ったと仮定し、板幅方向位置ｘにおける冷却水の流速νｐを下記式（１１）に示すようなｘの２次式で表したモデルを用いて計算すればよい。νｐはレイノルズ数Ｒｅのパラメータであるので、Ｒｅは下記式（１２）のようになる。このＲｅをヌッセルト数に反映させ、式（１０）〜式（１２）を用いて熱伝達率Ｈを計算することができる。 On the other hand, in the portion of the thick steel plate corresponding to the upper and lower headers adjacent to each other, the heat transfer coefficient is calculated in consideration of the cooling water flow velocity at the position in the plate width direction of the thick steel plate. For example, assuming that the x-axis is taken in the width direction with reference to the center portion of the thick steel plate, the flow rate ν p of the cooling water at the position x in the plate width direction is expressed by a quadratic expression of x as shown in the following formula (11). The calculation may be performed using the model. Since ν p is a parameter of the Reynolds number Re, Re is expressed by the following equation (12). This Re is reflected in the Nusselt number, and the heat transfer coefficient H can be calculated using the equations (10) to (12).
ここで、ａ１、ａ２、ａ３は係数を表す。また、Ｌは代表長さ［ｍ］、ρは冷却水密度［ｋｇ／ｍ３］、μは冷却水の粘性係数［ｍ・ｓ／ｋｇ］である。 Here, a 1 , a 2 , and a 3 represent coefficients. L is the representative length [m], ρ is the cooling water density [kg / m 3 ], and μ is the viscosity coefficient [m · s / kg] of the cooling water.
以上の２つのモデルを用いることにより、熱伝達率を計算することができ、幅方向表面温度むらを予測することができる。 By using the above two models, the heat transfer coefficient can be calculated, and the surface temperature unevenness in the width direction can be predicted.
図７に、幅方向温度むらを抑制するために、流量クラウン量を適正に設定した場合と、流量クラウン量を全く設定せずに幅方向流量を一定にした場合との比較を示す。図７（ａ）の縦軸は厚鋼板の上面温度［℃］であり、横軸は板幅中央から端部までの距離である。ここでは、冷却装置出側の厚鋼板の温度、冷却ゾーンＡ出側の厚鋼板の温度、および、冷却ゾーンＢ出側の厚鋼板の温度について、流量クラウン量を調整した場合を記号（■、◇、▲）で示し、流量クラウン量を調整しなかった場合を実線で示した。
図７（ｂ）は、流量クラウン量の調整形態を説明する図である。図７（ｂ）の縦軸は流量クラウン量を調整した時の水量密度［Ｌ／ｍ２・ｓ］であり、横軸は板幅中央からの距離［ｍ］である。
図７（ｃ）は、各冷却ゾーン（Ａ、Ｂ、Ｃ、Ｄ）および冷却装置の出側における厚鋼板端部の温度低下量［℃］を棒グラフで表した図である。
FIG. 7 shows a comparison between the case where the flow crown amount is set appropriately to suppress the width direction temperature unevenness and the case where the width direction flow rate is constant without setting the flow crown amount at all. The vertical axis | shaft of Fig.7 (a) is the upper surface temperature [degreeC] of a thick steel plate, and a horizontal axis is the distance from a plate width center to an edge part. Here, when the flow crown amount is adjusted with respect to the temperature of the steel plate on the outlet side of the cooling device, the temperature of the steel plate on the outlet side of the cooling zone A, and the temperature of the steel plate on the outlet side of the cooling zone B, symbols (■, ◇ and ▲) indicate the case where the flow crown amount was not adjusted.
FIG. 7B is a diagram for explaining a flow rate crown amount adjustment mode. The vertical axis of FIG. 7B is the water density [L / m 2 · s] when the flow crown amount is adjusted, and the horizontal axis is the distance [m] from the center of the plate width.
FIG.7 (c) is the figure which represented each cooling zone (A, B, C, D) and the temperature fall amount [degreeC] of the thick steel plate edge part in the exit side of a cooling device with the bar graph.
図７（ａ）〜（ｃ）に示したように、流量クラウン量の設定を行った場合には、板幅端部の温度降下が大幅に抑えられた。この結果から、流量クラウン量の調整は、幅方向温度むらの抑制に効果があることがわかる。 As shown in FIGS. 7A to 7C, when the flow crown amount was set, the temperature drop at the end of the plate width was greatly suppressed. From this result, it is understood that the adjustment of the flow amount crown amount is effective in suppressing the temperature direction temperature unevenness.
＜平坦度改善＞
厚鋼板の製造では平坦度制御が重要になる。一定以上の平坦度を確保できない場合には厚鋼板製造後に矯正作業が必要となり、工数および製造コストが増加する。
<Flatness improvement>
Flatness control is important in the manufacture of thick steel plates. When flatness of a certain level or more cannot be ensured, straightening work is required after manufacturing the thick steel plate, which increases the number of man-hours and manufacturing cost.
厚鋼板の平坦度は上下水量比に依存する。上下水量比の決定に際しては、過去の製造実績に基づいて決めれば良い。より具体的には、過去の製造実績が保存されている記憶部１１から、厚鋼板の操業条件に近い製造実績データを抽出し、製造実績データと平坦度合格率（矯正作業を行わなかった厚鋼板の割合）との関係を求め、この関係から上下水量比を決定すれば良い。上下水量比は、例えば、特願２０１１−１４９８３２に開示されている手順で決定することができる。 The flatness of the thick steel plate depends on the ratio of water quantity. What is necessary is just to determine based on the past manufacturing performance in the determination of water-and-water ratio. More specifically, manufacturing performance data close to the operating conditions of the thick steel plate is extracted from the storage unit 11 in which the past manufacturing performance is stored, and the manufacturing performance data and the flatness pass rate (thickness without correction work) What is necessary is just to obtain | require the relationship with the ratio of a steel plate, and to determine a water / water ratio from this relationship. The water / water ratio can be determined by, for example, the procedure disclosed in Japanese Patent Application No. 2011-149832.
ここで、操業条件に近い製造実績データの抽出では、操業条件として板厚、板幅、板長、冷却開始温度、冷却速度、冷却停止温度指示、カーボン当量、成分含有量、圧延ロール磨耗量、圧延デスケーリング回数などを用い、これらの条件値が近い過去の製造実績データをもって製造実績データとする。そして、抽出した製造実績データから、上下水量比、および、平坦度合格率の分布（ヒストグラムで良い）を求め、平坦度合格率が最も高くなる上下水量比を望ましい上下水量比とすれば良い。抽出する製造実績データ数は１００〜５００個程度が好ましい。これより多いと操業条件として近くない実績データをも抽出することになるため、適切な上下水量比を決定できなくなることがある。 Here, in the extraction of production performance data close to the operation conditions, the plate thickness, plate width, plate length, cooling start temperature, cooling rate, cooling stop temperature instruction, carbon equivalent, component content, rolling roll wear amount, Using the number of times of rolling descaling and the like, the past production record data having these condition values close to each other is used as the production record data. Then, from the extracted production performance data, the water and water ratio and the flatness pass rate distribution (which may be a histogram) are obtained, and the water and water ratio at which the flatness pass rate is the highest may be set as a desirable water and water ratio. The number of manufacturing performance data to be extracted is preferably about 100 to 500. If it is more than this, it will be impossible to determine an appropriate water and sewage ratio because it will also extract performance data that is not close as operating conditions.
図８に、特定の厚鋼板についての上下水量比ＲＴＢと平坦度との関係を示す。平坦度については平坦度合格率として、製造した厚鋼板の枚数に対する一定以上の平坦度を確保で
きた厚鋼板の枚数の割合を縦軸に示している。横軸は上下水量比ＲＴＢである。図８より、上下水量比ＲＴＢは０．７２近辺が望ましいことが分かる。
FIG. 8 shows the relationship between the water amount ratio R TB and the flatness for a specific thick steel plate. Regarding the flatness, the ratio of the number of thick steel plates that can secure a certain degree of flatness to the number of manufactured thick steel plates is shown on the vertical axis as the flatness acceptance rate. The horizontal axis is the water / water ratio R TB . FIG. 8 shows that the water / water ratio R TB is preferably around 0.72.
一般に、図９Ａに示すように、平坦度合格率は上下水量比ＲＴＢが１以下でピークを取り、高すぎても、低すぎても平坦度の合格率は悪化する。よって、製品ごとに適切な上下水量比ＲＴＢとすることが求められる。
図９Ｂに、厚鋼板の冷却に際して、前段冷却ゾーンの水量を少なくするとともに後段冷却ゾーンの水量を多くすることにより、前後段冷却比ＲＦＢを変更した場合の特定の厚鋼板についての、上下水量比ＲＴＢと平坦度合格率との関係を示す。図９Ａおよび図９Ｂの縦軸は平坦度合格率であり、図９Ａおよび図９Ｂの横軸は上下水量比である。図９Ｂより、上下水量比ＲＴＢは０．９５近辺が望ましいことが分かる。図９Ａおよび図９Ｂより、特定の厚鋼板でも前後段冷却比を変えると、冷却後平坦度が良好となる望ましい上下水量比は大きく変化することが分かる。
また、図９Ｃに、前後段冷却比を変えた２つの冷却パターン（パターン１の前後段冷却比ＲＦＢ１＜パターン２の前後段冷却比ＲＦＢ２）において、冷却後平坦度が良好であった上下水量比の実績データを示す。パターン２では、適正な上下水量比がパターン１よりも高いことが、図９Ｃに示されている。図９Ｃに示したように、前後段冷却比ＲＦＢが変わると、冷却後平坦度を良好にするための上下水量比が大きく変わる。そのため、前後段冷却比ＲＦＢを変える場合には、製造実績に関する情報として、前後段冷却比を抽出し、上下水量比を決定することが好ましいことが分かる。
In general, as shown in FIG. 9A, the flatness acceptance rate takes a peak when the water / water ratio R TB is 1 or less, and the flatness acceptance rate deteriorates even if it is too high or too low. Therefore, it is calculated | required to set it as appropriate water / water ratio RTB for every product.
In FIG. 9B, when cooling the thick steel plate, the amount of water in a specific thick steel plate when the front and rear cooling ratio RFB is changed by decreasing the amount of water in the preceding cooling zone and increasing the amount of water in the subsequent cooling zone. The relationship between ratio R TB and flatness pass rate is shown. The vertical axis in FIGS. 9A and 9B is the flatness pass rate, and the horizontal axis in FIGS. 9A and 9B is the water amount ratio. From FIG. 9B, it can be seen that the upper and lower water amount ratio R TB is preferably around 0.95. From FIG. 9A and FIG. 9B, it can be seen that when the front / rear cooling ratio is changed even for a specific thick steel plate, the desirable water / water ratio that provides good flatness after cooling varies greatly.
9C shows two cooling patterns with different front-rear cooling ratios (front-rear cooling ratio R FB1 of pattern 1 <front-rear cooling ratio R FB2 of pattern 2). The actual data of water volume ratio is shown. FIG. 9C shows that the appropriate water / water ratio is higher in pattern 2 than in pattern 1. As shown in FIG. 9C, when the front / rear cooling ratio RFB changes, the water / water ratio for improving the flatness after cooling greatly changes. Therefore, when changing front-and-back stage cooling ratio RFB , it turns out that it is preferable to extract a front-and-back stage cooling ratio and to determine water-and-water ratio, as information regarding a manufacturing performance.
＜温度むらと平坦度との相関関係＞
以上、長手方向温度むら、幅方向温度むら、および、平坦度についてそれぞれ述べたが、お互い相関関係があり、それぞれ独立して実施した場合には適切な冷却制御が行えない。このため、以下のように水冷制御を行う必要がある。
<Correlation between temperature unevenness and flatness>
As described above, the longitudinal temperature unevenness, the widthwise temperature unevenness, and the flatness have been described. However, there is a correlation between them, and appropriate cooling control cannot be performed when implemented independently. For this reason, it is necessary to perform water cooling control as follows.
図１０に、冷却制御の概要図を示す。
過去の製造実績データを用いて上下水量比を求める際には、記憶部１１から、当該冷却対象材の操業条件に近い過去実績データを抽出し、その抽出された過去実績データの上下水量比と平坦度合格率との関係を求め、この関係から上下水量比を決定（算出）する。
FIG. 10 shows a schematic diagram of the cooling control.
When obtaining the water and water ratio using the past production performance data, the past performance data close to the operating conditions of the material to be cooled is extracted from the storage unit 11, and the water and water ratio of the extracted past performance data and The relationship with the flatness pass rate is obtained, and the water / water ratio is determined (calculated) from this relationship.
上下水量比の決定に続き、流量クラウン量を決定する。流量クラウン量を決定する際には、先に決定した上下水量比を用いる。上下水量比をパラメータとして流量クラウン量を決定することで、平坦度の悪化を回避することができる。そして、最後に、上下水量比および流量クラウン量を用いて、冷却装置にてダイナミック制御を行う。 Following the determination of the water / water ratio, the flow crown is determined. When determining the flow crown amount, the previously determined water / water ratio is used. By determining the flow crown amount using the water / water ratio as a parameter, deterioration of flatness can be avoided. And finally, dynamic control is performed by the cooling device using the water / water ratio and the flow crown amount.
以上のような工程を通して、平坦度が良好であり、温度むらが低減され、均一な品質を有する厚鋼板を製造することができる。図１１は、本発明の厚鋼板の製造方法を説明する図である。図１１に示したように、本発明の厚鋼板の製造方法は、厚鋼板を仕上圧延する工程Ｓ２１と、工程Ｓ２１で仕上圧延された厚鋼板を冷却する工程Ｓ２２と、を有し、当該工程Ｓ２２で、上記本発明の厚鋼板の冷却制御方法が適用される。
なお、冷却後の厚鋼板は平坦度を測定し、製造条件等と平坦度とを紐付けしてデータベースに保存する。データを蓄積することにより、次以降の厚鋼板の製造時に、より最適な上下水量比を算出できるようになる。
Through the steps as described above, it is possible to produce a thick steel plate having good flatness, reduced temperature unevenness, and uniform quality. FIG. 11 is a diagram for explaining a method of manufacturing a thick steel plate according to the present invention. As shown in FIG. 11, the manufacturing method of the thick steel plate of the present invention includes a step S21 for finish rolling the thick steel plate, and a step S22 for cooling the thick steel plate finish-rolled in the step S21. In S22, the cooling control method for the thick steel plate of the present invention is applied.
The flat steel plate after cooling is measured for flatness, and the manufacturing conditions and the flatness are linked and stored in a database. By accumulating data, it becomes possible to calculate a more optimal water and sewage ratio at the time of manufacturing subsequent thick steel plates.
図１２は、本発明の厚鋼板の製造装置１００を説明する図である。図１２では、厚鋼板の製造装置１００に備えられる各装置を簡略化して示しており、図１と同様に構成されるものには、図１で使用した符号と同一の符号を付している。
図１２に示したように、本発明の厚鋼板の製造装置１００は、厚鋼板を仕上圧延する圧延機３０と、圧延機３０で圧延された厚鋼板の温度を測定する温度計２と、圧延機３０で圧延された厚鋼板を冷却する冷却装置２０と、該冷却装置２０の動作を制御する冷却制御装置１０と、冷却装置２０で冷却された厚鋼板の温度を測定する温度計３と、を備えている。厚鋼板の製造装置１００は、本発明の厚鋼板の冷却制御装置１０によって動作を制御される冷却装置２０を用いて厚鋼板を冷却するので、平坦度が良好であり、温度むらが低減され、均一な品質を有する厚鋼板を製造することができる。
FIG. 12 is a diagram for explaining a thick steel plate manufacturing apparatus 100 according to the present invention. In FIG. 12, each apparatus with which the thick steel plate manufacturing apparatus 100 is provided is shown in a simplified manner, and components similar to those in FIG. 1 are denoted by the same reference numerals as those used in FIG. .
As shown in FIG. 12, the thick steel plate manufacturing apparatus 100 of the present invention includes a rolling mill 30 that finish-rolls the thick steel plate, a thermometer 2 that measures the temperature of the thick steel plate rolled by the rolling mill 30, and a rolling A cooling device 20 for cooling the thick steel plate rolled by the machine 30, a cooling control device 10 for controlling the operation of the cooling device 20, a thermometer 3 for measuring the temperature of the thick steel plate cooled by the cooling device 20, It has. Since the thick steel plate manufacturing apparatus 100 cools the thick steel plate using the cooling device 20 whose operation is controlled by the thick steel plate cooling control device 10 of the present invention, the flatness is good, the temperature unevenness is reduced, A thick steel plate having uniform quality can be manufactured.
本発明に関する上記説明では、上下水量比決定部１２、厚鋼板移動速度予測部１４、冷却ゾーン通過所要時間計算部１５、現在温度計算部１６、温度分布予測部１７、流量分布決定部１８、および、制御部１９を別々に示したが、本発明の厚鋼板の冷却制御装置は当該形態に限定されず、これらすべての機能を兼ね備えた１つの制御部が備えられる形態とすることも可能である。 In the above description regarding the present invention, the water / water ratio determination unit 12, the steel plate moving speed prediction unit 14, the cooling zone passage required time calculation unit 15, the current temperature calculation unit 16, the temperature distribution prediction unit 17, the flow rate distribution determination unit 18, and Although the control unit 19 is shown separately, the thick steel plate cooling control device of the present invention is not limited to this form, and it is possible to adopt a form in which one control unit having all these functions is provided. .
１…厚鋼板
２、３…温度計
１０…厚鋼板の冷却制御装置
１１…記憶部（記憶手段）
１２…上下水量比決定部
１３…トラッキング部
１４…厚鋼板移動速度予測部
１５…冷却ゾーン通過所要時間計算部
１６…現在温度計算部
１７…温度分布予測部
１８…流量分布決定部
１９…制御部
２０…冷却装置
２１…上面ヘッダー群
２１ａ…上面ヘッダー
２１ｂ…ノズル
２１ｃ…仕切り板
２１ｄ…枝給水管
２１ｅ…バルブ
２２…下面ヘッダー群
２２ａ…下面ヘッダー
３０…圧延機
１００…厚鋼板の製造装置
DESCRIPTION OF SYMBOLS 1 ... Thick steel plate 2, 3 ... Thermometer 10 ... Thick steel plate cooling control apparatus 11 ... Memory | storage part (memory | storage means)
DESCRIPTION OF SYMBOLS 12 ... Vertical water amount ratio determination part 13 ... Tracking part 14 ... Thick steel plate moving speed prediction part 15 ... Cooling zone passage required time calculation part 16 ... Current temperature calculation part 17 ... Temperature distribution prediction part 18 ... Flow rate distribution determination part 19 ... Control part DESCRIPTION OF SYMBOLS 20 ... Cooling device 21 ... Upper surface header group 21a ... Upper surface header 21b ... Nozzle 21c ... Partition plate 21d ... Branch water supply pipe 21e ... Valve 22 ... Lower surface header group 22a ... Lower surface header 30 ... Rolling mill 100 ... Manufacturing apparatus of thick steel plate
Claims (8)
過去の製造実績から、冷却される前記厚鋼板の平坦度合格率が所定値以上になる前記冷却装置の上下水量比を決定する工程と、
決定された前記上下水量比、および、これ以外の製造条件から、前記厚鋼板の幅方向における冷却後の温度分布を予測する工程と、
予測した前記冷却後の温度分布の幅が一定値以下になる、前記厚鋼板の幅方向における冷却水の流量分布を決定する工程と、
決定された前記上下水量比、および、決定された前記冷却水の流量分布となるように、前記冷却装置へと供給される冷却水の水量を、前記厚鋼板の冷却中に変動させるように制御する工程と、
を有する、厚鋼板の冷却制御方法。 A method of controlling cooling of a thick steel plate that passes through a water cooling zone of a cooling device,
From the past production results, the step of determining the water and water ratio of the cooling device in which the flatness pass rate of the thick steel plate to be cooled is equal to or higher than a predetermined value;
From the determined water and water ratio, and other manufacturing conditions, predicting the temperature distribution after cooling in the width direction of the thick steel plate,
The step of determining the flow rate distribution of the cooling water in the width direction of the thick steel plate, the predicted width of the temperature distribution after cooling becomes a certain value or less,
Control is performed so that the amount of cooling water supplied to the cooling device is varied during cooling of the thick steel plate so that the determined ratio of the amount of water to water and the flow rate distribution of the determined cooling water are obtained. And a process of
A method for controlling cooling of a thick steel plate.
前記仕上圧延する工程の後に前記厚鋼板を冷却する工程と、を有し、
前記冷却する工程で、請求項１〜３のいずれか１項に記載の厚鋼板の冷却制御方法が適用されることを特徴とする、厚鋼板の製造方法。 A step of finish rolling the steel plate;
And a step of cooling the thick steel plate after the step of finish rolling,
The method for manufacturing a thick steel plate according to any one of claims 1 to 3, wherein the cooling control method for the thick steel plate according to any one of claims 1 to 3 is applied in the cooling step.
過去の製造実績に関する情報を保存する記憶部と、
前記記憶部に保存されている過去の製造実績から、冷却される前記厚鋼板の平坦度合格率が所定値以上になる前記冷却装置の上下水量比を決定する上下水量比決定部と、
決定した前記上下水量比、および、これ以外の製造条件から、前記厚鋼板の幅方向における冷却後の予測温度の分布を求める温度分布予測部と、
前記温度分布予測部で求めた前記冷却後の予測温度の分布幅が一定値以下になる、前記厚鋼板の幅方向における冷却水の流量分布を決定する流量分布決定部と、
前記上下水量比決定部で決定された前記上下水量比、および、前記流量分布決定部で決定された前記冷却水の流量分布となるように、前記冷却装置へと供給される冷却水の水量を、前記厚鋼板の冷却中に変動させるように制御する制御部と、
を有する、厚鋼板の冷却制御装置。 A cooling control device for controlling the amount of cooling water supplied to a cooling device for cooling the finish-rolled thick steel plate,
A storage unit for storing information on past manufacturing results;
From the past production results stored in the storage unit, the water / water ratio determination unit for determining the water / water ratio of the cooling device in which the flatness pass rate of the thick steel plate to be cooled is equal to or higher than a predetermined value;
From the determined water and water ratio, and other production conditions, a temperature distribution prediction unit for obtaining a predicted temperature distribution after cooling in the width direction of the thick steel plate,
A flow rate distribution determining unit that determines a flow rate distribution of the cooling water in the width direction of the thick steel plate, wherein the distribution range of the predicted temperature after cooling obtained by the temperature distribution predicting unit is a certain value or less;
The amount of cooling water supplied to the cooling device is adjusted so that the water / water flow ratio determined by the water / water ratio determination unit and the flow rate distribution of the cooling water determined by the flow distribution determination unit are obtained. A control unit that controls the steel plate to change during cooling of the thick steel plate;
A thick steel plate cooling control device.
前記冷却制御装置が、請求項５〜７のいずれか１項に記載の厚鋼板の冷却制御装置である、厚鋼板の製造装置。 A rolling mill for finish rolling the thick steel plate, a cooling device for cooling the thick steel plate rolled by the rolling mill, and a cooling control device for controlling the operation of the cooling device,
An apparatus for manufacturing a thick steel plate, wherein the cooling control device is the cooling control device for a thick steel plate according to any one of claims 5 to 7.
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