JP2017001085A - Thick steel plate cooling control method, cooling control device, manufacturing method, and manufacturing device - Google Patents

Abstract

To provide a cooling control method for a thick steel plate capable of controlling the cooling stop temperature with high accuracy. The temperature of the thick steel plate is measured with a thermometer on the cooling device inlet side, and the temperature of the thick steel plate is predicted using the steel plate temperature prediction model starting from this measured temperature. Set the cooling water amount of the entire cooling device to lower the predicted temperature to the target temperature, blow the cooling water of the set water amount onto the thick steel plate to cool the thick steel plate, and the temperature installed in the cooling device Measure the temperature of the thick steel plate as it passes through the thermometer using a meter so that the predicted temperature of the thick steel plate at the thermometer position in the cooling device matches the measured value of the temperature of the thick steel plate in the cooling device Next, adjust the steel plate temperature prediction model, and use the adjusted steel plate temperature prediction model to reset the amount of cooling water downstream from the thermometer position in the cooling device and cool the cooling water of the reset amount of water. To a thick steel plate downstream of the thermometer position in the equipment Sprayed, the cooling control method for steel plate. [Selection] Figure 1

Description

  The present invention relates to a cooling control method for controlling the cooling mode of a thick steel plate, a method for manufacturing a thick steel plate using the same, a cooling control device for controlling the cooling mode of the thick steel plate, and a manufacturing apparatus for the thick steel plate using the same.

  In temperature control in the cooling process of thick steel plates, the steel plate temperature change due to water cooling is estimated by heat transfer calculation before cooling starts, and the amount of cooling water and the steel plate conveyance speed in the cooling device are determined so as to obtain the target cooling stop temperature Then, cooling is performed under the determined conditions. Therefore, the estimation accuracy of the steel plate temperature change by water cooling influences the control accuracy of the cooling stop temperature. If the actual cooling stop temperature is far from the target value, the mechanical characteristics required for the product cannot be obtained, so that it is required to control the steel plate temperature after cooling (cooling stop temperature) with high accuracy. Moreover, in order to improve production efficiency, the length of a thick steel plate tends to be long, and it is required to control the cooling stop temperature with high accuracy over the longitudinal direction of the steel plate.

  In the cooling of thick steel plates, appropriate operating conditions (such as the amount of cooling water and the steel plate conveyance speed) are derived using a steel plate temperature prediction model before cooling the steel plates, and cooling is performed under these conditions. In general, a thick steel plate has a short steel plate length and a long distance from the cooling device to the cooling stop thermometer. Therefore, even if feedback control is applied to operate the cooling device so as to suppress the control deviation of the stop temperature during cooling of the steel plate, it is possible to control the cooling stop temperature with high accuracy over the entire length in the longitudinal direction of the steel plate. Can not.

  Technologies for improving the control of the cooling stop temperature include (1) increasing the accuracy of the steel plate temperature prediction model, and (2) learning to offset the error of the steel plate temperature prediction model after cooling the steel plate, A combination of the two can be considered.

  However, since it is difficult to consider all changes in the cooling state due to scale and surface properties on the steel plate before cooling the steel plate, there is a limit to increasing the accuracy of the steel plate temperature prediction model. Learning to supplement this is effective for cooling the thick steel plate that is cooled next to the thick steel plate that is currently being cooled, so that the cooling stop temperature of the thick steel plate that is currently being cooled can be made highly accurate. I can't.

Several techniques related to steel sheet cooling control have been disclosed so far. For example, in Patent Document 1, the surface temperature measurement value of a thick steel plate after cooling is stopped and before completion of double heat is used to estimate the plate thickness direction temperature distribution of the thick steel plate, and the estimated plate thickness direction temperature distribution is used. A technique is disclosed in which the cooling water amount of the cooling device is feedback-controlled so that the cooling stop temperature matches the cooling stop temperature target value.
Further, in Patent Document 2, the cooling stop temperature on the cooling device exit side is predicted from the steel plate temperature measurement value on the cooling device entrance side, and the predicted cooling stop temperature matches the target value of the cooling stop temperature. A dynamic control technique for sequentially operating the cooling water amount of the cooling device is disclosed.
Patent Document 3 discloses a method in which cooling water is supplied to a steel plate from a nozzle arranged up and down while the hot-rolled steel plate is transferred in the longitudinal direction of the steel plate, and then cooled in the longitudinal direction of the cooling device. For each cooling zone in which the vertical water injection amount can be controlled, the temperature difference between the upper and lower surfaces of the steel sheet is detected at the entry side of each cooling zone. A method for cooling a hot-rolled steel sheet to be controlled is disclosed.
Further, in Patent Document 4, a prediction error is estimated using a database in which past performance data is accumulated, a correction value of the cooling stop temperature is calculated using the estimated prediction error, and this correction value is the cooling stop temperature. A cooling control method for a thick steel plate is disclosed in which the amount of cooling water and the steel plate conveyance speed are determined so as to achieve the target value.
Further, in Patent Document 5, in the course of hot rolling, when the hot rolling is continued by changing to another hot rolling condition different from the predetermined hot rolling condition, the other hot Based on the rolling conditions and the temperature measurement value of the steel plate on the inlet side of the water cooling device located on the most upstream side of the plurality of water cooling devices, the coiling temperature of the steel plate can be set as a target value. The set values of the cooling conditions for all the water cooling devices are obtained, and the other hot rolling conditions and the input of one or more water cooling devices other than the water cooling device located on the most upstream side among the plurality of water cooling devices. Based on the temperature measurement value of the steel plate on the side, at least one of the above cooling conditions set for the one or more water cooling devices is corrected and set, and the water cooling device can be controlled independently. Multiple water amounts to adjust the amount of cooling water injected Together with an integer valve, the cooling condition is a degree of opening of the water control valve, a manufacturing method of hot-rolled steel sheet is disclosed.

Japanese Patent No. 5493993 Japanese Patent No. 5392143 Japanese Patent No. 1980092 JP 2012-81518 A Japanese Patent No. 4894686

  In the technique described in Patent Document 1, since the cooling water amount is fed back by using the surface temperature measurement value of the thick steel plate after the cooling stop and before the completion of the double heat, the portion that has passed through the cooling device before the feedback control is reflected. The control accuracy of the cooling stop temperature cannot be increased. Moreover, in the technique described in Patent Document 2, the amount of cooling water is manipulated according to the temperature prediction result calculated from the steel plate temperature measurement value on the cooling device entry side. Therefore, the prediction accuracy of the steel plate temperature prediction model affects the control accuracy. However, the prediction error may increase during cooling inside the cooling device due to factors that are difficult to predict, such as the remaining scale on the surface of the steel sheet, so this technology has room to increase the control accuracy of the cooling stop temperature. It was left. In addition, the technique described in Patent Document 3 suppresses the occurrence of a steel sheet shape defect due to a thermal shrinkage difference by controlling the amount of water injection so that the temperature difference between the upper and lower surfaces of the thick steel sheet is reduced. This is not a technique aimed at increasing the control accuracy of the cooling stop temperature of the steel sheet. Further, the technique described in Patent Document 4 relies on past performance data, and therefore cannot cope with any change that occurs in the steel sheet that is currently being cooled. Moreover, the technique described in Patent Document 5 is a technique for a hot-rolled steel sheet having a thin plate thickness. When temperature prediction is performed based on the measurement value, it is necessary to give a temperature distribution in the thickness direction at the measurement position, but this document does not describe the temperature distribution. Therefore, this technique cannot be directly applied to the plate thickness direction temperature distribution of the thick steel plate. If the steel plate is thin, the temperature distribution in the plate thickness direction is small even during cooling, so there is almost no effect on the accuracy even if this is not taken into consideration. However, in the case of a thick steel plate, the temperature difference between the surface in the plate thickness direction and the central portion during cooling is as high as several hundred degrees C. Therefore, the temperature distribution in the plate thickness direction cannot be ignored. In order to control the cooling stop temperature of the thick steel plate with high accuracy, it is necessary to accurately predict the temperature distribution in the thickness direction.

  The present invention has been made in view of the above-described problems, and is capable of controlling the cooling stop temperature with high accuracy, and a cooling control method and a cooling control device for a thick steel plate, and a manufacturing method for the thick steel plate and It is an object to provide a manufacturing apparatus.

As a result of intensive studies, the inventors measured the steel plate temperature during cooling by installing a thermometer in the cooling device in order to prevent the prediction error from expanding during cooling due to factors that are difficult to predict. The cooling stop temperature was predicted from the thermometer position. Thereby, since it becomes possible to shorten a prediction area conventionally, it becomes possible to suppress the fall of the prediction precision based on the factor which is difficult to predict. Furthermore, the steel plate temperature prediction model is adjusted in real time so that the predicted value and the measured value of the steel plate temperature at the thermometer position in the cooling device match, and the amount of cooling water in the cooling section downstream from the thermometer position is fed. We decided to control forward. Thereby, it becomes possible to raise the control precision of steel plate temperature in the cooling zone downstream from the said thermometer position.
The present invention has been completed based on such findings. The present invention will be described below.

  1st aspect of this invention cools by spraying a cooling water to the thick steel plate conveyed after hot rolling, and manipulates the amount of cooling water so that the temperature of the thick steel plate after cooling may become predetermined | prescribed temperature Using a possible cooling device, predict the temperature of the thick steel plate after cooling using the steel plate temperature prediction model, derive the amount of cooling water at which the predicted steel plate temperature becomes the specified temperature, and cool the thick steel plate with the derived cooling water amount A method for controlling cooling of a thick steel plate, the first temperature measuring step of measuring the temperature of the thick steel plate when passing through the thermometer using a thermometer installed on the inlet side of the cooling device; The first temperature prediction step of predicting the temperature of the thick steel plate using the steel plate temperature prediction model starting from the temperature measured in the first temperature measurement step, and the cooling device predicted in the first temperature prediction step The temperature of the thick steel plate on the delivery side is lowered to the target cooling stop temperature. A cooling water amount setting step for setting the cooling water amount of the entire cooling device, and cooling the thick steel plate by blowing the cooling water of the cooling water amount set in the first cooling water amount setting step onto the thick steel plate The first cooling step, the second temperature measuring step for measuring the temperature of the thick steel plate when passing through the thermometer using the thermometer installed in the cooling device, and the first temperature prediction step. Further, the steel plate temperature prediction model is adjusted so that the predicted value of the temperature of the thick steel plate at the thermometer position in the cooling device matches the measured value of the temperature of the thick steel plate measured in the second temperature measurement step. An adjustment step, a second temperature prediction step of predicting the temperature of the thick steel plate in the region downstream of the thermometer position in the cooling device using the steel plate temperature prediction model adjusted in the adjustment step, and the second The cooling device output predicted in the temperature prediction process A second cooling water amount setting step for resetting the cooling water amount of the cooling device in the region downstream of the thermometer position in the cooling device for lowering the temperature of the thick steel plate to the cooling stop target temperature; A second cooling step of cooling the thick steel plate by spraying the cooling water of the cooling water amount set in the cooling water amount setting step onto the thick steel plate downstream of the thermometer position in the cooling device, It is a cooling control method of a steel plate.

  In the present invention, the calculation result of the steel plate temperature prediction model includes the plate thickness direction temperature distribution of the thick steel plate. In the present invention, the “incoming side” refers to the upstream side in the conveying direction of the thick steel plate, and the “outside” refers to the downstream side in the conveying direction of the thick steel plate. In the first aspect of the present invention, the temperature of the thick steel plate is measured by the thermometer in the cooling device, and the amount of cooling water downstream from the thermometer in the cooling device is determined using this measured value. The thick steel plate is cooled by spraying a sufficient amount of cooling water onto the thick steel plate downstream of the thermometer in the cooling device. By setting it as such a form, since the area which estimates a steel plate temperature using a steel plate temperature prediction model in a 2nd temperature prediction process can be shortened conventionally, the disturbance factor which deteriorates the prediction precision of a steel plate temperature is produced. It is possible to reduce the accuracy of the prediction of the steel plate temperature. Furthermore, in the first aspect of the present invention, the temperature measurement value by the thermometer in the cooling device matches the predicted value of the temperature at the thermometer position in the cooling device predicted from the temperature on the cooling device entry side. The steel plate temperature prediction model is adjusted so that the cooling water amount of the cooling device in the region downstream from the thermometer position in the cooling device is reset using the adjusted steel plate temperature prediction model. Thereby, it becomes possible to raise the control precision of steel plate temperature in the cooling section downstream from the thermometer position in the cooling device. Therefore, according to the 1st aspect of this invention, the cooling control method of a thick steel plate which can control cooling stop temperature with high precision can be provided.

  Further, in the first aspect of the present invention, the steel sheet temperature prediction model includes a heat transfer coefficient in a nucleate boiling region, a heat transfer coefficient in a transition boiling region, and film boiling on a thick steel plate surface cooled by cooling water. A heat transfer coefficient calculation unit for calculating the heat transfer coefficient of the region, a transition temperature between the nucleate boiling region and the transition boiling region (hereinafter sometimes referred to as “CHF point”), and a transition boiling region and film boiling. A transition temperature calculation unit for calculating a transition temperature with the region (hereinafter, sometimes referred to as “MHF point”), and the adjustment of the steel sheet temperature prediction model in the adjustment step is performed with the transition from the nucleate boiling region. It is performed by correcting the transition temperature (CHF point) with the boiling region, the transition temperature (MHF point) between the transition boiling region and the film boiling region, the heat transfer coefficient of the nucleate boiling region, and the heat transfer coefficient of the transition boiling region. It is preferable. By adopting such a form, it becomes easy to control the cooling stop temperature with high accuracy.

  In the second aspect of the present invention, cooling is performed by spraying cooling water onto the transported thick steel plate after hot rolling, and the amount of cooling water is manipulated so that the temperature of the thick steel plate after cooling becomes a predetermined temperature. Using a possible cooling device, predict the temperature of the thick steel plate after cooling using the steel plate temperature prediction model, derive the amount of cooling water at which the predicted steel plate temperature becomes the specified temperature, and cool the thick steel plate with the derived cooling water amount This is a method for controlling the cooling of a thick steel plate, and considers the thick steel plate as an aggregate of a plurality of cut plates virtually divided in the longitudinal direction, and uses a thermometer installed on the inlet side of the cooling device. Then, using the steel sheet temperature prediction model, starting from the first cut plate temperature measurement step for measuring the temperature of each cut plate when passing through the thermometer, and the temperature measured in the first cut plate temperature measurement step, A first cutting plate temperature prediction step for predicting the temperature of each cutting plate, A first cooling water amount setting step for setting a cooling water amount of the entire cooling device for reducing the temperature of each cutting plate on the outlet side of the cooling device predicted in the cutting plate temperature prediction step to a cooling stop target temperature; Using a first cooling step that cools each of the cutting plates by blowing the cooling water of the amount of cooling water set in the one cooling water amount setting step onto each of the cutting plates, and a thermometer installed in the cooling device The second cut plate temperature measuring step for measuring the temperature of each cut plate when passing through the thermometer and the first cut plate temperature predicting step predicted for each cut plate at the thermometer position in the cooling device. An adjustment step of adjusting the steel plate temperature prediction model for each cut plate so that the predicted value of the temperature matches the measured value of the temperature of each cut plate measured in the second cut plate temperature measurement step; The steel sheet temperature prediction model adjusted in the adjustment process A second cutting plate temperature prediction step for predicting the temperature of each cutting plate in a region downstream of the thermometer position in the cooling device, and the outlet side of the cooling device predicted in the second cutting plate temperature prediction step The second cooling water amount setting step for resetting the cooling water amount of the cooling device for each cutting plate in the region downstream of the thermometer position in the cooling device for lowering the temperature of each cutting plate to the cooling stop target temperature And by blowing the cooling water of the amount of cooling water set in the second cooling water amount setting step to each of the cutting plates on the downstream side of the thermometer position in the cooling device, A cooling control method for a thick steel plate.

  In the second aspect of the present invention, the temperature of each cut plate is measured by the thermometer in the cooling device, and the amount of cooling water on the downstream side of the thermometer in the cooling device is determined and determined using this measured value. The thick steel plate, which is an aggregate of the cut plates, is cooled by spraying the cooling water of the amount of water that has been applied to the cut plates on the downstream side of the thermometer in the cooling device. By adopting such a configuration, the section for predicting the steel plate temperature using the steel plate temperature prediction model in the second cut plate temperature prediction step can be shortened as compared with the conventional case, so that the disturbance that deteriorates the prediction accuracy of the steel plate temperature. The factor is reduced, and the accuracy of predicting the steel sheet temperature can be increased. Furthermore, in the second aspect of the present invention, the temperature measurement value by the thermometer in the cooling device matches the predicted value of the temperature at the thermometer position in the cooling device predicted from the temperature on the cooling device entry side. The steel plate temperature prediction model is adjusted so that the cooling water amount of the cooling device in the region downstream from the thermometer position in the cooling device is reset using the adjusted steel plate temperature prediction model. Thereby, it becomes possible to raise the control precision of steel plate temperature in the cooling section downstream from the thermometer position in the cooling device. Furthermore, in the 2nd aspect of this invention, since cooling control with respect to all the cut plates is performed, it becomes possible to raise the control precision of steel plate temperature over the longitudinal direction full length of a thick steel plate. Therefore, according to the 2nd aspect of this invention, the cooling control method of a thick steel plate which can control a cooling stop temperature with high precision can be provided.

  Also, in the second aspect of the present invention, the steel sheet temperature prediction model includes a heat transfer coefficient of a nucleate boiling region, a heat transfer coefficient of a transition boiling region, and a film on each cut plate surface cooled by cooling water. A heat transfer coefficient calculation unit for calculating a heat transfer coefficient of the boiling region, a transition temperature (CHF point) between the nucleate boiling region and the transition boiling region, and a transition temperature (MHF point) between the transition boiling region and the film boiling region The adjustment of the steel sheet temperature prediction model in the adjustment step includes the transition temperature (CHF point) between the nucleate boiling region and the transition boiling region, the transition boiling region and the film boiling region. This is preferably performed by correcting the transition temperature (MHF point), the heat transfer coefficient of the nucleate boiling region, and the heat transfer coefficient of the transition boiling region. By adopting such a form, it becomes easy to control the cooling stop temperature with high accuracy.

  A third aspect of the present invention includes a step of hot rolling a thick steel plate, and a step of cooling the thick steel plate after the hot rolling step. It is a manufacturing method of a thick steel plate using the cooling control method of the thick steel plate concerning 1 aspect or the said 2nd aspect of this invention.

  In the third aspect of the present invention, when the thick steel plate is cooled, the thick steel plate cooling control method according to the first aspect of the present invention or the second aspect of the present invention is used. Since the cooling control method for a thick steel plate according to the present invention can control the cooling stop temperature with high accuracy, it is possible to control the cooling stop temperature with high accuracy by adopting such a configuration. The manufacturing method of can be provided.

  4th aspect of this invention is a cooling control apparatus which controls the operating condition of the cooling device which cools the hot-rolled thick steel plate, Comprising: It installs in each in the inlet side and outlet side of a cooling device, and in a cooling device The thickness when passing through the thermometer measured using a thermometer installed on the inlet side of the cooling device (hereinafter sometimes referred to as “entry-side thermometer”). A first temperature prediction unit that predicts the temperature of the thick steel plate in a region downstream from the position of the entry-side thermometer, using the steel plate temperature prediction model, with the temperature of the steel plate as a starting point, and prediction by the first temperature prediction unit Cooling device for reducing the temperature of the thick steel plate at the position of a thermometer (hereinafter sometimes referred to as "exit-side thermometer") installed on the outlet side of the cooled cooling device to the cooling stop target temperature A first cooling water amount setting unit for setting the entire cooling water amount; 1 Estimated value of the temperature of the thick steel plate at the position of the thermometer installed in the cooling device (hereinafter sometimes referred to as “cooling device thermometer”) predicted by the temperature prediction unit, and the cooling device Using the adjustment unit that adjusts the steel plate temperature prediction model so that the measured value of the temperature of the thick steel plate measured using the internal thermometer matches, and the steel plate temperature prediction model adjusted by the adjustment unit A second temperature predicting unit that predicts the temperature of the thick steel plate in a region downstream of the position of the thermometer in the cooling device, and the temperature of the thick steel plate at the position of the exit side thermometer predicted by the second temperature predicting unit A second cooling water amount setting unit for resetting the cooling water amount of the cooling device in the region downstream of the position of the thermometer in the cooling device for reducing the cooling water to the target temperature for cooling stop. Device.

  In the fourth aspect of the present invention, the amount of cooling water on the downstream side of the position of the thermometer in the cooling device is determined using the temperature measurement value of the thick steel plate measured by the thermometer in the cooling device. By setting it as such a form, since the area which estimates a steel plate temperature using a steel plate temperature prediction model in a 2nd temperature prediction part can be shortened rather than before, the disturbance factor which deteriorates the prediction precision of a steel plate temperature is produced. It is possible to reduce the accuracy of the prediction of the steel plate temperature. Furthermore, in the fourth aspect of the present invention, the temperature measurement value by the cooling device thermometer matches the predicted temperature value at the position of the cooling device thermometer predicted from the temperature on the cooling device entry side. In this manner, the steel plate temperature prediction model is adjusted, and the cooling water amount of the cooling device in the region downstream of the position of the cooling device thermometer is reset using the adjusted steel plate temperature prediction model. Thereby, it becomes possible to raise the control precision of steel plate temperature in the cooling section downstream from the position of the thermometer in the cooling device. Therefore, according to the 4th aspect of this invention, the cooling control apparatus of a thick steel plate which can control a cooling stop temperature with high precision can be provided.

  Further, in the fourth aspect of the present invention, the steel sheet temperature prediction model includes a heat transfer coefficient in a nucleate boiling region, a heat transfer coefficient in a transition boiling region, and film boiling on a thick steel plate surface cooled by cooling water. Heat transfer coefficient calculation unit for calculating the heat transfer coefficient of the region, the transition temperature (CHF point) between the nucleate boiling region and the transition boiling region, and the transition temperature (MHF point) between the transition boiling region and the film boiling region The adjustment of the steel sheet temperature prediction model in the adjustment unit includes the transition temperature (CHF point) between the nucleate boiling region and the transition boiling region, and the transition temperature between the transition boiling region and the film boiling region. This is preferably performed by correcting the (MHF point), the heat transfer coefficient of the nucleate boiling region, and the heat transfer coefficient of the transition boiling region. By adopting such a form, it becomes easy to control the cooling stop temperature with high accuracy.

  According to a fifth aspect of the present invention, there is provided a cooling control device for controlling operating conditions of a cooling device for cooling a hot-rolled thick steel plate, wherein the thick steel plate is virtually divided into a plurality of cuts in the longitudinal direction. It is regarded as an assembly of plates, and thermometers installed on the inlet side and outlet side of the cooling device and on the inside of the cooling device, respectively, measured using the inlet side thermometer, and each when passing through the thermometer A first cut plate temperature prediction unit that predicts the temperature of each cut plate in a region downstream from the position of the entry side thermometer using the steel plate temperature prediction model, starting from the cut plate temperature, and the first cut A first cooling water amount setting unit for setting the cooling water amount of the entire cooling device for lowering the temperature of each cut plate at the position of the outlet thermometer predicted by the plate temperature prediction unit to the cooling stop target temperature; At the position of the thermometer in the cooling device predicted by the cutting plate temperature prediction unit An adjustment unit that adjusts the steel sheet temperature prediction model so that the predicted value of the temperature of each cut plate matches the measured value of the temperature of each cut plate measured using the thermometer in the cooling device; A second cutting plate temperature prediction unit that predicts the temperature of each cutting plate in a region downstream of the position of the thermometer in the cooling device using the steel plate temperature prediction model adjusted by the adjustment unit; Cooling for each cut plate in the region downstream of the position of the thermometer in the cooling device for lowering the temperature of each cut plate at the position of the outgoing thermometer predicted by the plate temperature prediction unit to the cooling stop target temperature It is a cooling control apparatus of a thick steel plate which has a 2nd cooling water amount setting part which resets the cooling water amount of an apparatus.

  In the fifth aspect of the present invention, the amount of cooling water downstream from the position of the cooling device thermometer is determined using the temperature measurement value of each cut plate measured by the cooling device thermometer. By adopting such a configuration, the section for predicting the steel plate temperature using the steel plate temperature prediction model in the second cut plate temperature prediction unit can be shortened as compared with the conventional case, so that the disturbance that deteriorates the prediction accuracy of the steel plate temperature. The factor is reduced, and the accuracy of predicting the steel sheet temperature can be increased. Furthermore, in the fifth aspect of the present invention, the temperature measurement value by the cooling device thermometer matches the predicted temperature value at the position of the cooling device thermometer predicted from the temperature on the cooling device entry side. In this manner, the steel plate temperature prediction model is adjusted, and the cooling water amount of the cooling device in the region downstream of the position of the cooling device thermometer is reset using the adjusted steel plate temperature prediction model. Thereby, it becomes possible to raise the control precision of steel plate temperature in the cooling section downstream from the position of the thermometer in the cooling device. Furthermore, in the fifth aspect of the present invention, since cooling control is performed on all the cut plates, it is possible to increase the control accuracy of the steel plate temperature over the entire length in the longitudinal direction of the thick steel plate. Therefore, according to the fifth aspect of the present invention, it is possible to provide a thick steel plate cooling control apparatus capable of controlling the cooling stop temperature with high accuracy.

  Further, in the fifth aspect of the present invention, the steel sheet temperature prediction model includes a heat transfer coefficient of a nucleate boiling region, a heat transfer coefficient of a transition boiling region, and a film on each cut plate surface cooled by cooling water. A heat transfer coefficient calculation unit for calculating a heat transfer coefficient of the boiling region, a transition temperature (CHF point) between the nucleate boiling region and the transition boiling region, and a transition temperature (MHF point) between the transition boiling region and the film boiling region The adjustment of the steel sheet temperature prediction model in the adjustment unit includes the transition temperature (CHF point) between the nucleate boiling region and the transition boiling region, the transition boiling region and the film boiling region. This is preferably performed by correcting the transition temperature (MHF point), the heat transfer coefficient of the nucleate boiling region, and the heat transfer coefficient of the transition boiling region. By adopting such a form, it becomes easy to control the cooling stop temperature with high accuracy.

  A sixth aspect of the present invention includes a rolling mill for hot rolling a thick steel plate, a cooling device for cooling the thick steel plate hot rolled by the rolling mill, and a cooling control device for controlling the operation of the cooling device, , And the cooling control apparatus is a thick steel sheet manufacturing apparatus according to the fourth aspect of the present invention or the thick steel sheet cooling control apparatus according to the fifth aspect of the present invention.

  In the sixth aspect of the present invention, the operation of the cooling device for cooling the thick steel plate is performed using the cooling control device for the thick steel plate according to the fourth aspect of the present invention or the fifth aspect of the present invention. Be controlled. The thick steel plate cooling control apparatus according to the present invention can control the cooling stop temperature with high accuracy. By adopting such a configuration, the thick steel plate can control the cooling stop temperature with high accuracy. The manufacturing apparatus can be provided.

  ADVANTAGE OF THE INVENTION According to this invention, the cooling control method and cooling control apparatus of a thick steel plate which can control a cooling stop temperature with high precision, and the manufacturing method and manufacturing apparatus of a thick steel plate can be provided.

It is a flowchart explaining the cooling control method of the thick steel plate of this invention. It is a figure explaining the cooling control method of the thick steel plate of this invention. It is a figure which shows a boiling curve. It is a figure explaining a steel plate temperature prediction model. It is a figure which shows a boiling curve. It is a flowchart explaining the cooling control method of the thick steel plate of this invention. It is a figure explaining the cooling control method of the thick steel plate of this invention. It is a figure explaining the manufacturing method of the thick steel plate of this invention. It is a figure explaining the cooling control apparatus 30 of a thick steel plate, and the manufacturing apparatus 100 of a thick steel plate. It is a figure explaining the cooling control apparatus 40 of a thick steel plate, and the manufacturing apparatus 200 of a thick steel plate. It is a figure explaining an example of a temperature fall simulation result.

  Embodiments of the present invention will be described below. In addition, the following forms are illustrations of the present invention, and the present invention is not limited to the forms described below.

1. Thick Steel Plate Cooling Control Method The thick steel plate cooling control method of the present invention (hereinafter sometimes referred to as “control method of the present invention”) is a thermometer installed in the cooling device (cooling device thermometer). The feedforward control technology that predicts the cooling stop temperature of the thick steel plate after cooling using the steel plate temperature prediction model, starting from the measured value of, and sets the operation amount (cooling water amount) of the cooling device based on this prediction result It is. The thick steel plate cooled by the cooling device is guided to the cooling device by being conveyed at a predetermined speed after hot rolling. The cooling device cools the thick steel plate by spraying cooling water toward the thick steel plate moving at a predetermined conveyance speed. In order to control the cooling stop temperature of the thick steel plate with high accuracy, it is necessary to predict with high accuracy the temperature change of the thick steel plate until the cooling stop using the measurement value of the thermometer as a starting point. In the control method of the present invention, the form in which the thick steel plate is considered as an aggregate of a plurality of cut plates virtually divided in the longitudinal direction (first embodiment) and the form not considered as an aggregate of a plurality of cut plates (first) 2 embodiment).

1.1. 1st Embodiment FIG.1 and FIG.2 is a figure explaining the control method of this invention concerning 1st Embodiment. The control method of the present invention according to the first embodiment will be described below with reference to FIGS. 1 and 2 as appropriate.
The control method of the present invention according to the first embodiment shown in FIG. 1 includes a first cutting plate temperature measurement step S11, a first cutting plate temperature prediction step S12, a first cooling water amount setting step S13, and a first cooling. It has process S14, 2nd cutting board temperature measurement process S15, adjustment process S16, 2nd cutting board temperature prediction process S17, 2nd cooling water amount setting process S18, and 2nd cooling process S19. .

1.1.1. First cut plate temperature measurement step S11
The first cut plate temperature measurement step S <b> 11 (hereinafter sometimes referred to as “S <b> 11”) passes through the entry-side thermometer 11 using the entry-side thermometer 11 installed on the entry side of the cooling device 20. It is the process of measuring the temperature of each cutting board when doing.

1.1.2. First cut plate temperature prediction step S12
In the first cut plate temperature prediction step S12 (hereinafter sometimes referred to as “S12”), a steel plate temperature prediction model (plate thickness direction multi-division model) is started from the temperature of each cut plate measured in S11. By using the calculated temperature drop of each cut plate, it was installed at the position of each of the cooling device thermometers 12, 13, 14 installed in the cooling device 20 and on the outlet side of the cooling device 20. This is a step of predicting the temperature (plate thickness direction temperature distribution) of each cut plate at the position of the delivery-side thermometer 15.

  The thick steel plate 1 cooled by spraying cooling water from the cooling device 20 is cooled through different boiling states. A boiling curve for explaining the relationship between the surface temperature of the thick steel plate and the heat flux is shown in FIG. As shown in FIG. 3, when the surface temperature of the thick steel plate is high, it is in a state of film boiling where a water vapor film is formed, and the boiling state changes from transition boiling to nucleate boiling as the surface temperature decreases. And the change of a heat flux becomes large with the temperature (MHF point) which changes from a film | membrane boiling region to a transition boiling region, and the temperature (CHF point) which changes from a transition boiling region to a nucleate boiling region. In S12, the temperature of each cut plate is predicted using the heat transfer coefficient of the film boiling area, the heat transfer coefficient of the transition boiling area, the heat transfer coefficient of the nucleate boiling area, the MHF point, and the CHF point.

  The temperature of the thick steel plate can be represented by a one-dimensional heat conduction equation in the plate thickness direction shown in the following formula (1).

  The boundary conditions on the upper and lower surfaces of the thick steel plate are given by the following formulas (2) and (3).

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.

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.

Here, T _s is the surface temperature of the steel plate [° 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 the convection. Heat transfer coefficient.

The heat flux _qr due to radiation can be written as follows using the emissivity ε and the Stefan-Boltzmann constant σ.

  Control of thick steel sheet 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 point can be calculated.

  Here, the heat transfer coefficient Hw of water cooling is calculated by a method disclosed in, for example, Japanese Patent Application Laid-Open No. 2011-167754.

  FIG. 4 is a diagram for explaining a steel plate temperature prediction model. In the model shown in FIG. 4, when calculating the heat transfer coefficient of the portion of the thick steel plate sandwiched between the upper header and the lower header (hereinafter referred to as “upper and lower header”), a set of upper and lower nozzles (upper header) The region on the thick steel plate is divided into concentric cells centering on the jet direction of the nozzles arranged in the nozzle 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. 4, 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.

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 CHF point and the MHF point can be obtained by experiments or the like. The temperature region between the CHF point and the MHF point is called a transition boiling region where nucleate boiling and film boiling occur simultaneously, as shown in FIG. If the surface temperature of the thick steel plate is below the CHF point, the nucleate boiling rate is 100%, and if it is above the MHF point, the film boiling rate 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.

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 (7) and (8), the ratio of the boiling state is added to these, and the heat transfer coefficient is calculated by formula (9). A transmission rate H is calculated.

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 subcool degree [° C.], T _s is the surface temperature [° C.] of the thick steel plate, T _w is the jet water temperature [° C.], and B is the nucleate boiling rate (0 ≦ B ≦ 1).

  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 thick steel plate 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.

  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.

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 respect to the central portion of the thick steel plate, the flow rate ν _p of the cooling water at the plate width direction position x is expressed by a quadratic expression of x as shown in the following formula (10). The calculation may be performed using the model. Since ν _p is a parameter of the Reynolds number Re, Re is represented by the following formula (11). This Re is reflected in the Nusselt number, and the heat transfer coefficient H can be calculated using the equations (9) to (11).

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.

  By using the above two models, the heat transfer coefficient can be calculated and the temperature of the thick steel plate can be predicted.

1.1.3. First cooling water amount setting step S13
In the first cooling water amount setting step S13 (hereinafter may be referred to as “S13”), the temperature of each cut plate at the position of the delivery-side thermometer 15 predicted in S12 is reduced to the cooling stop target temperature. This is a step of setting the cooling water amount of the entire cooling device 20 for the purpose. In S13, the amount of cooling water in all the cooling zones of the cooling device 20 necessary for cooling each cut plate whose plate thickness direction temperature distribution is predicted in S12 to the cooling stop target temperature is set for each cut plate.

1.1.4. 1st cooling process S14
The first cooling step S14 (hereinafter may be referred to as “S14”) is a step of cooling each cut plate by spraying the amount of cooling water set in S13 onto each cut plate. It is. More specifically, it is a step of cooling each cutting plate while controlling the operation of the cooling device 20 so that the cooling water of the cooling water amount set in S13 is sprayed to each cutting plate.

1.1.5. Second cut plate temperature measurement step S15
The second cut plate temperature measurement step S15 (hereinafter sometimes referred to as “S15”) is performed at the position of the thermometers 12, 13, and 14 in the cooling device between the start and the end of S14. This is a step of measuring the reached temperature of each cut plate using the thermometers 12, 13, and 14 in the cooling device. That is, S15 is a step of measuring the temperature of each cut plate being cooled by the cooling device 20.

1.1.6. Adjustment process S16
The adjustment step S16 (hereinafter may be referred to as “S16”) is a predicted value of the temperature of each cutting plate at each position of the cooling device thermometers 12, 13, and 14 predicted in S12. In the process of adjusting the steel sheet temperature prediction model for each cut plate so that the measured values of the temperature of each cut plate at the respective positions of the thermometers 12, 13, and 14 measured in S15 coincide. is there. The adjustment of the steel plate temperature prediction model in S16 is not particularly limited as long as the steel plate temperature prediction model is adjusted so that the temperature prediction value in S12 matches the temperature measurement value in S15. However, from the viewpoint of making the cooling stop temperature easy to control with high accuracy, the steel plate temperature prediction model used in the control method of the present invention is the heat transfer in the nucleate boiling region of each cut plate surface cooled by the cooling water. It is preferable to have a heat transfer coefficient calculation unit that calculates the heat transfer coefficient of the rate, the transition boiling region, and the film transfer region, and a transition temperature calculation unit that calculates the CHF point and the MHF point. S16 is preferably a step of correcting the CHF point, MHF point, nucleate boiling region heat transfer coefficient, and transition boiling region heat transfer coefficient in such a steel sheet temperature prediction model.

For the correction of the CHF point and the MHF point, for example, the CHF point and the MHF point are moved in the same direction (high temperature side or low temperature side; the same applies hereinafter) so that the predicted temperature value of S12 matches the measured temperature value of S15. It can be implemented by correcting the same amount and performing convergence calculation. When the CHF point and the MHF point are corrected by the same amount in the same direction, the heat transfer coefficient of the nucleate boiling region is corrected by multiplying the heat transfer coefficient before correction by a correction coefficient Xn expressed by the following equation. be able to. In the following formula, ΔT is a correction amount (° C.) of the CHF point and the MHF point.
Xn = 1.0 + 0.02 · ΔT
Moreover, the heat transfer coefficient of the transition boiling region after correction can be represented by, for example, a straight line connecting the heat transfer coefficient of the nucleate boiling region after correction at the CHF point and the heat transfer coefficient of the film boiling region at the MHF point. . An example of the boiling curve used in the steel sheet temperature prediction model adjusted in S16 is shown in FIG. In FIG. 5, the boiling curve before adjustment, the CHF point and the MHF point are corrected to 38.1 ° C. on the high temperature side, and the heat transfer coefficient correction coefficient Xn in the nucleate boiling region is adjusted to 1.76. A boiling curve was shown.

1.1.7. Second cut plate temperature prediction step S17
The second cut plate temperature prediction step S17 (hereinafter, sometimes referred to as “S17”) includes the position of the exit side thermometer 15 using the steel plate temperature prediction model adjusted in S16. This is a step of predicting the temperature of each cut plate (plate thickness direction temperature distribution) at a position downstream of the positions of the thermometers 12, 13, and 14. The temperature prediction calculation in S17 can be performed in the same manner as S12 except that the steel plate temperature prediction model adjusted in S16 is used.

1.1.8. Second cooling water amount setting step S18
The second cooling water amount setting step S18 (hereinafter may be referred to as “S18”) is the temperature of each cut plate predicted at S17 on the outlet side of the cooling device 20 (the position of the outlet thermometer 15). Is a step of resetting the cooling water amount of the cooling device 20 for each cut plate in the region downstream of the position where the temperature is measured in S15 for lowering the cooling stop target temperature. The resetting of the cooling water amount in S18 can be performed in the same manner as in S13, except that the result predicted in S17 is used as the plate thickness direction temperature distribution that is the starting point used when determining the cooling water amount.

1.1.9. Second cooling step S19
In the second cooling step S19 (hereinafter, sometimes referred to as “S19”), the amount of the cooling water set in S18 is transferred to each of the cutting plates on the downstream side of the position where the temperature is measured in S15. This is a step of cooling each cut plate by spraying. More specifically, it is a step of cooling each cutting plate while controlling the operation of the cooling device 20 so that the cooling water amount reset in S18 is sprayed onto each cutting plate.

  As described above, in the control method of the present invention according to the first embodiment, the temperature of each cut plate is measured by the thermometers 12, 13, and 14 in the cooling device in S15, and the cooling device is used in S18 using this measured value. The amount of cooling water on the downstream side of the inner thermometers 12, 13, and 14 is determined, and the cooling water of the determined amount is sprayed onto each cut plate, thereby cooling the thick steel plate 1 that is an aggregate of the cut plates. By adopting such a form, the steel plate temperature prediction model is used in S17 using the steel plate temperature prediction model in S17 as compared with the conventional case where the steel plate temperature on the downstream side is predicted based on the temperature measurement result by the inlet side thermometer 11. Since the section for predicting the temperature can be shortened, disturbance factors that deteriorate the prediction accuracy of the steel plate temperature are reduced, and the prediction accuracy of the steel plate temperature can be increased. Furthermore, in the control method of the present invention according to the first embodiment, the steel plate temperature prediction model is adjusted and adjusted in S16 so that the temperature measurement value measured in S15 and the temperature prediction value predicted in S12 coincide. In step S18, the cooling water amount of the cooling device is reset using the steel plate temperature prediction model. Thereby, it becomes possible to raise the control precision of steel plate temperature in the cooling section downstream from the position of the thermometers 12, 13, and 14 in the cooling device. Furthermore, in the control method of the present invention according to the first embodiment, since cooling control is performed on all the cut plates, it is possible to increase the control accuracy of the steel plate temperature over the entire length in the longitudinal direction of the thick steel plate 1. Therefore, by adopting such a form, it is possible to provide a thick steel plate cooling control method capable of controlling the cooling stop temperature with high accuracy.

1.2. Second Embodiment FIGS. 6 and 7 are diagrams for explaining a control method of the present invention according to a second embodiment. The control method of the present invention according to the second embodiment will be described below with reference to FIGS. 6 and 7 as appropriate. In addition, although 1st Embodiment tracks each cutting board which passes a cooling device, it is embodiment targeted at the cooling device which can spray the cooling water of the required amount of water with respect to each cutting plate. The second embodiment is an embodiment directed to a cooling device that does not have such a function.
The control method of the present invention according to the second embodiment shown in FIG. 6 includes a first temperature measurement step S21, a first temperature prediction step S22, a first cooling water amount setting step S23, a first cooling step S24, It has 2nd temperature measurement process S25, adjustment process S26, 2nd temperature prediction process S27, 2nd cooling water amount setting process S28, and 2nd cooling process S29.

1.2.1. First temperature measurement step S21
The first temperature measurement step S <b> 21 (hereinafter may be referred to as “S <b> 21”) uses the entry-side thermometer 11 installed on the entry side of the cooling device 20 to pass through the entry-side thermometer 11. It is the process of measuring the temperature of the front-end | tip part which is a control object point of this thick steel plate 1. FIG.

1.2.2. First temperature prediction step S22
The first temperature prediction step S22 (hereinafter sometimes referred to as “S22”) uses a steel plate temperature prediction model (plate thickness direction multi-division model) starting from the temperature of the thick steel plate 1 measured in S21. By calculating the temperature drop of the thick steel plate 1, the respective positions of the cooling device thermometers 12, 13, 14 installed in the cooling device 20 and the outlet side installed on the outlet side of the cooling device 20 This is a step of predicting the temperature (thickness direction temperature distribution) of the thick steel plate 1 at the position of the thermometer 15. Except that the thick steel plate 1 is not regarded as an aggregate of a plurality of cut plates, S22 is a process similar to S12, and thus detailed description thereof is omitted here.

1.2.3. First cooling water amount setting step S23
In the first cooling water amount setting step S23 (hereinafter may be referred to as “S23”), the temperature of the thick steel plate 1 at the position of the outlet thermometer 15 predicted in S22 is lowered to the cooling stop target temperature. This is a step of setting the cooling water amount of the entire cooling device 20 for the purpose. In S23, the cooling water amount in all the cooling zones of the cooling device 20 necessary for cooling the thick steel plate 1 whose plate thickness direction temperature distribution is predicted in S22 to the cooling stop target temperature is set.

1.2.4. 1st cooling process S24
The first cooling step S24 (hereinafter may be referred to as “S24”) is a step of cooling the thick steel plate 1 by spraying the amount of cooling water set in S23 onto the thick steel plate 1. . More specifically, it is a step of cooling the thick steel plate 1 while controlling the operation of the cooling device 20 so that the amount of cooling water set in S23 is sprayed onto the thick steel plate 1.

1.2.5. Second temperature measurement step S25
The second temperature measurement step S25 (hereinafter sometimes referred to as “S25”) has reached the positions of the thermometers 12, 13, and 14 in the cooling device between the start and the end of S24. This is a step of measuring the temperature at the tip, which is the point to be controlled, of the thick steel plate 1 using the cooling device thermometers 12, 13, and 14. That is, S25 is a step of measuring the temperature of the thick steel plate 1 being cooled by the cooling device 20.

1.2.6. Adjustment process S26
The adjustment step S26 (hereinafter may be referred to as “S26”) is a predicted value of the temperature of the thick steel plate 1 at each position of the cooling device thermometers 12, 13, and 14 predicted in S22. This is a step of adjusting the steel plate temperature prediction model so that the measured values of the temperature of the thick steel plate 1 at the positions of the cooling device thermometers 12, 13, and 14 measured in S25 coincide. The adjustment of the steel plate temperature prediction model in S26 is not particularly limited as long as the steel plate temperature prediction model is adjusted so that the temperature prediction value in S22 matches the temperature measurement value in S25. However, from the viewpoint of making the cooling stop temperature easy to control with high accuracy, the steel plate temperature prediction model used in the control method of the present invention is the heat transfer coefficient of the nucleate boiling region on the surface of the thick steel plate cooled by the cooling water. It is preferable to have a heat transfer coefficient calculator that calculates the heat transfer coefficient of the transition boiling region and the heat transfer coefficient of the film boiling region, and a transition temperature calculator that calculates the CHF point and the MHF point. And it is preferable that S26 is a process of correcting the CHF point, the MHF point, the heat transfer coefficient of the nucleate boiling region, and the heat transfer coefficient of the transition boiling region in such a steel sheet temperature prediction model. Except that the thick steel plate 1 is not regarded as an aggregate of a plurality of cut plates, S26 is a process similar to S16, and thus detailed description thereof is omitted here.

1.2.7. Second temperature prediction step S27
The second temperature prediction step S27 (hereinafter may be referred to as “S27”) includes the position of the outlet thermometer 15 using the steel plate temperature prediction model adjusted in S26, and includes a thermometer in the cooling device. This is a step of predicting the temperature (plate thickness direction temperature distribution) of the thick steel plate 1 at a position downstream of the positions 12, 13, and 14. The temperature prediction calculation in S27 can be performed in the same manner as S22 except that the steel plate temperature prediction model adjusted in S26 is used.

1.2.8. Second cooling water amount setting step S28
In the second cooling water amount setting step S28 (hereinafter sometimes referred to as “S28”), the temperature of the thick steel plate 1 on the outlet side of the cooling device 20 (position of the outlet thermometer 15) predicted in S27. Is a step of resetting the cooling water amount of the cooling device 20 in the region downstream of the position at which the temperature is measured in S25 for reducing the temperature to the cooling stop target temperature. The resetting of the cooling water amount in S28 can be performed in the same manner as in S23, except that the result predicted in S27 is used as the plate thickness direction temperature distribution that is the starting point used when determining the cooling water amount.

1.2.9. Second cooling step S29
In the second cooling step S29 (hereinafter sometimes referred to as “S29”), the amount of cooling water set in S28 is transferred to the thick steel plate 1 on the downstream side of the position where the temperature is measured in S25. This is a step of cooling the thick steel plate 1 by spraying. More specifically, it is a step of cooling the thick steel plate 1 while controlling the operation of the cooling device 20 so that the cooling water amount reset in S28 is sprayed onto the thick steel plate 1.

  Thus, in the control method of the present invention according to the second embodiment, the temperature of the thick steel plate 1 is measured by the thermometers 12, 13, and 14 in the cooling device in S25, and the cooling device is used in S28 using this measured value. The thickness of the thick steel plate 1 is cooled by determining the amount of cooling water downstream of the inner thermometers 12, 13, and 14 and spraying the determined amount of cooling water onto the thick steel plate 1. By adopting such a form, the steel plate temperature prediction model is used in S27 using a steel plate temperature prediction model in S27 as compared with the conventional case where the steel plate temperature on the downstream side is predicted based on the temperature measurement result by the inlet side thermometer 11. Since the section for predicting the temperature can be shortened, disturbance factors that deteriorate the prediction accuracy of the steel plate temperature are reduced, and the prediction accuracy of the steel plate temperature can be increased. Furthermore, in the control method of the present invention according to the second embodiment, the steel plate temperature prediction model is adjusted in S26 so that the temperature measurement value measured in S25 matches the temperature prediction value predicted in S22. In step S28, the cooling water amount of the cooling device is reset using the steel plate temperature prediction model. Thereby, it becomes possible to raise the control precision of steel plate temperature in the cooling section downstream from the position of the thermometers 12, 13, and 14 in the cooling device. Therefore, by adopting such a form, it is possible to provide a thick steel plate cooling control method capable of controlling the cooling stop temperature with high accuracy.

2. Manufacturing Method of Thick Steel Plate FIG. 8 is a diagram for explaining a manufacturing method of a thick steel plate according to the present invention. As shown in FIG. 8, the manufacturing method of the thick steel plate of the present invention includes a hot rolling step S31 for hot rolling the thick steel plate, a cooling step S32 for cooling the thick steel plate after the hot rolling step S31, In the cooling step S32, the control method of the present invention according to the first embodiment or the second embodiment is used. As described above, according to the control method of the present invention, the cooling stop temperature can be controlled with high accuracy. By having such cooling process S32, in the manufacturing method of the thick steel plate of this invention, the cooling stop temperature of a thick steel plate is controlled with high precision. Thereby, since it becomes possible to stabilize the mechanical characteristic of a thick steel plate, the manufacturing method of a thick steel plate which can reduce an additive element and can reduce manufacturing cost can be provided.

3. Thick steel plate cooling control device and thick steel plate manufacturing device 3.1. First Embodiment FIG. 9 is a view for explaining an example of a thick steel plate manufacturing apparatus 100 according to the first embodiment, which includes the thick steel plate cooling control apparatus 30 according to the first embodiment. is there. The manufacturing apparatus 100 shown in FIG. 9 controls the rolling mill 10 that hot-rolls thick steel plates, the cooling device 20 that cools the thick steel plates hot-rolled by the rolling mill 10, and the operating conditions of the cooling device 20. The cooling control device 30, the inlet-side thermometer 11 installed on the inlet side of the cooling device 20, the cooling-device thermometers 12, 13, 14 installed in the cooling device 20, and the outlet side of the cooling device 20 And an exit-side thermometer 15 installed. The cooling control device 30 is a device capable of executing the control method of the present invention according to the first embodiment.

  The cooling control device 30 shown in FIG. 9 includes an inlet-side thermometer 11, cooling-device thermometers 12, 13, and 14, an outlet-side thermometer 15, a first cut plate temperature prediction unit 31, and a first cooling A water amount setting unit 32, an adjustment unit 33, a second cut plate temperature prediction unit 34, and a second cooling water amount setting unit 35 are included. The first cut plate temperature prediction unit 31 is a part where S12 is performed, and the steel plate is started from the temperature of each cut plate when passing through the input side thermometer 11 measured using the input side thermometer 11. The temperature of each cut plate after cooling is predicted using a temperature prediction model. The first cut plate temperature prediction unit 31 predicts the plate thickness direction temperature distribution of each cut plate. Information regarding the thickness distribution in the thickness direction of each cut plate thus predicted is sent to the first cooling water amount setting unit 32 and the adjustment unit 33, and S13 is performed in the first cooling water amount setting unit 32. Specifically, in the first cooling water amount setting unit 32, the temperature of each cutting plate at the position of the outlet thermometer 15 predicted by the first cutting plate temperature prediction unit 31 is decreased to the cooling stop target temperature. The amount of cooling water for the entire cooling device 20 is calculated. Information regarding the amount of cooling water calculated in this way is sent to the cooling device 20. Then, by blowing the cooling water of the cooling water amount calculated by the first cooling water amount setting unit 32 toward each of the cutting plates conveyed at a predetermined conveying speed in the cooling device 20, each cutting plate is cooled every moment. Is done. In the manufacturing apparatus 100, the temperature of each cut plate in the cooling device 20 is measured using the cooling device thermometers 12, 13, and 14 while each cut plate is being cooled by the cooling device 20. . Information about the temperature of each cut plate measured using the thermometers 12, 13, and 14 in the cooling device is sent to the adjustment unit 33 and the second cut plate temperature prediction unit 34. And the predicted value of the temperature of each cutting board in the position of the thermometer 12 in a cooling device, 13, 14 estimated by the 1st cutting plate temperature prediction part 31 and the thermometer 12 in a cooling device 12, 13, 14 are used. The steel plate temperature prediction model is adjusted by the adjustment unit 33 so that the measured temperature values of the respective cut plates coincide with each other. The adjustment unit 33 is a part where S16 is performed. For example, the steel plate temperature prediction model is adjusted by correcting the CHF point, the MHF point, the heat transfer coefficient of the nucleate boiling area, and the heat transfer coefficient of the transition boiling area. Is done. When the steel plate temperature prediction model is adjusted in this way, the second cut plate temperature prediction unit 34 in which S17 is performed is measured using the adjusted steel plate temperature prediction model and the cooling device thermometers 12, 13, and 14. Using the measured value of the temperature of each cut plate, the temperature of each cut plate (plate thickness direction temperature distribution) in the region downstream of the position of the thermometer 12, 13, 14 in the cooling device is predicted. . Information about the temperature of each cut plate predicted by the second cut plate temperature prediction unit 34 is sent to the second cooling water amount setting unit 35 in which S18 is performed. And in the area | region downstream from the position of the thermometer 12 in a cooling device, 13, 14 for reducing the temperature of each cutting board sent from the 2nd cutting board temperature prediction part 34 to cooling stop target temperature The cooling water amount of the cooling device 20 for each cut plate is calculated by the second cooling water amount setting unit 35. Information regarding the amount of cooling water calculated in this way is sent to the cooling device 20. And it calculates with the 2nd cooling water amount setting part 35 toward each cutting board conveyed downstream from the position of the thermometer 12 in a cooling device 20, 13, 13 and 14 with a predetermined conveyance speed. By blowing the cooling water of the amount of the cooling water, each cut plate is cooled every moment.

  Thus, the cooling control apparatus 30 can implement the control method of the present invention according to the first embodiment. According to the control method of the present invention according to the first embodiment, the cooling stop temperature can be controlled with high accuracy. Therefore, according to the present invention, the cooling stop temperature can be controlled with high accuracy. A control device 30 can be provided. The thick steel plate manufacturing apparatus 100 includes such a cooling control device 30. Therefore, according to this invention, the manufacturing apparatus 100 of a thick steel plate which can control a cooling stop temperature with high precision can be provided. In addition, since it becomes possible to stabilize the mechanical characteristics of the thick steel plate by controlling the cooling stop temperature with high accuracy, the manufacturing apparatus 100 for the thick steel plate reduces the manufacturing cost by reducing the additive elements. It is also possible to reduce it.

3.2. Second Embodiment FIG. 10 is a diagram for explaining an example of a thick steel plate manufacturing apparatus 200 according to a second embodiment, which includes the thick steel plate cooling control apparatus 40 according to the second embodiment. is there. The manufacturing apparatus 200 shown in FIG. 10 controls the rolling mill 10 that hot-rolls thick steel plates, the cooling device 20 that cools the thick steel plates hot-rolled by the rolling mill 10, and the operating conditions of the cooling device 20. The cooling control device 40, the inlet-side thermometer 11 installed on the inlet side of the cooling device 20, the cooling-device thermometers 12, 13, 14 installed in the cooling device 20, and the outlet side of the cooling device 20 And an exit-side thermometer 15 installed. The cooling control device 40 is a device capable of executing the control method of the present invention according to the second embodiment.

  The cooling control device 40 shown in FIG. 10 includes an inlet-side thermometer 11, cooling-device thermometers 12, 13, and 14, an outlet-side thermometer 15, a first temperature prediction unit 41, and a first cooling water amount setting. A unit 42, an adjustment unit 43, a second temperature prediction unit 44, and a second cooling water amount setting unit 45. The first temperature prediction unit 41 is a part where S22 is performed, and is measured using the entry-side thermometer 11, and the temperature of the tip that is the control target point of the thick steel plate when passing through the entry-side thermometer 11 Is used to predict the temperature of the thick steel plate after cooling using a steel plate temperature prediction model. In the 1st temperature prediction part 41, the plate thickness direction temperature distribution of a thick steel plate is estimated. Information on the temperature distribution in the thickness direction of the thick steel plate thus predicted is sent to the first cooling water amount setting unit 42 and the adjusting unit 43, and S23 is performed in the first cooling water amount setting unit 42. Specifically, in the first cooling water amount setting unit 42, cooling for reducing the temperature of the thick steel plate at the position of the delivery-side thermometer 15 predicted by the first temperature prediction unit 41 to the cooling stop target temperature. The amount of cooling water for the entire apparatus 20 is calculated. Information regarding the amount of cooling water calculated in this way is sent to the cooling device 20. And a thick steel plate is cooled by spraying the cooling water of the amount of cooling water calculated in the 1st cooling water amount setting part 42 toward the thick steel plate conveyed in the cooling device 20 at a predetermined conveyance speed. In the manufacturing apparatus 200, while the thick steel plate is being cooled by the cooling device 20, the temperature of the tip part, which is the control target point of the thick steel plate in the cooling device 20, uses the thermometers 12, 13, 14 in the cooling device. Measured. Information related to the temperature of the thick steel plate measured using the thermometers 12, 13, and 14 in the cooling device is sent to the adjustment unit 43 and the second temperature prediction unit 44. And it measures using the predicted value of the temperature of the thick steel plate in the position of the thermometer 12 in a cooling device 12,13,14 predicted by the 1st temperature prediction part 41, and the thermometer 12 in a cooling device 12,13,14. The steel plate temperature prediction model is adjusted by the adjustment unit 43 so that the measured value of the temperature of the thick steel plate matches. The adjustment unit 43 is a part where S26 is performed. For example, the steel plate temperature prediction model is adjusted by correcting the CHF point, the MHF point, the heat transfer coefficient of the nucleate boiling area, and the heat transfer coefficient of the transition boiling area. Is done. When the steel plate temperature prediction model is adjusted in this way, the second temperature prediction unit 44 in which S27 is performed is measured using the adjusted steel plate temperature prediction model and the cooling device thermometers 12, 13, and 14. Using the measured value of the temperature of the thick steel plate, the temperature (thickness direction temperature distribution) of the thick steel plate in the region downstream from the position of the thermometers 12, 13, and 14 in the cooling device is predicted. Information about the temperature of the thick steel plate predicted by the second temperature prediction unit 44 is sent to the second cooling water amount setting unit 45 in which S28 is performed. And the cooling device 20 in the area | region downstream from the position of the thermometer in a cooling device 12,13,14 for reducing the temperature of the thick steel plate sent from the 2nd temperature prediction part 44 to cooling stop target temperature. Is calculated by the second cooling water amount setting unit 45. Information regarding the amount of cooling water calculated in this way is sent to the cooling device 20. Then, the cooling water amount calculated by the second cooling water amount setting unit 45 is directed toward the steel plate that is transported at a predetermined transport speed on the downstream side of the thermometers 12, 13, and 14 in the cooling device 20. The thick steel plate is cooled by spraying the cooling water.

  Thus, the cooling control apparatus 40 can implement the control method of the present invention according to the second embodiment. According to the control method of the present invention relating to the second embodiment, the cooling stop temperature can be controlled with high accuracy. Therefore, according to the present invention, the cooling stop temperature can be controlled with high accuracy. A control device 40 can be provided. The thick steel plate manufacturing apparatus 200 includes such a cooling control apparatus 40. Therefore, according to this invention, the manufacturing apparatus 200 of a thick steel plate which can control cooling stop temperature with high precision can be provided. In addition, since it becomes possible to stabilize the mechanical characteristics of the thick steel plate by controlling the cooling stop temperature with high accuracy, the manufacturing apparatus 200 for the thick steel plate reduces the manufacturing cost by reducing the additive elements. It is also possible to reduce it.

  In the above description related to the present invention, the mode in which the thermometer in the cooling device is installed between the plurality of cooling zones (ABCD) provided in the cooling device (between AB, BC, and CD) is exemplified. The installation location of the thermometer in the cooling device is not limited to this. When the amount of cooling water in the cooling zone can be controlled by a plurality of valves, a cooling device thermometer is installed in the cooling zone, and cooling of the thick steel plate can be controlled using this cooling device thermometer. Is possible.

  Moreover, in the said description regarding this invention, although the form which uses the measurement result by all the thermometers 12, 13, and 14 in a cooling device was illustrated, this invention is not limited to the said form. In the present invention, at least one of the thermometers installed in the cooling device may be used. In addition, since the one where the prediction area is shorter is more accurate as the prediction accuracy of the steel plate temperature, it is preferable to control the cooling of the thick steel plate using a thermometer on the downstream side in the cooling device.

  The present invention will be further described with reference to simulation examples.

  Results of temperature drop simulation (present invention) performed on the assumption that the control method of the present invention according to the first embodiment was applied to the thick steel plate manufacturing apparatus 100 for steel type A having a plate thickness of 22 mm, and a cooling device FIG. 11 shows the result of a temperature drop simulation (comparative example) according to a conventional method in which the temperature of the thick steel plate is not measured during cooling by 20. Moreover, the boiling curve before and behind adjusted with the control method of this invention is shown in FIG.

  As shown in FIG. 5, in the boiling curve, since the transition temperature of the boiling state is + 38.1 ° C., the heat flux increases from the higher temperature side. In addition, the heat transfer coefficient of the nucleate boiling region was corrected to 1.76 (= 1.0 + 0.02 × 38.1) times, and the heat transfer coefficient of the transition boiling region was corrected accordingly. The heat transfer coefficient was not changed.

As a result of performing a temperature drop simulation until the cooling stop using the boiling curve shown in FIG. 5, as shown in FIG. 11, in the present invention, the temperature prediction accuracy can be improved by adjusting the temperature prediction model, The predicted value and the measured value of the cooling stop temperature almost coincided. Using this adjusted temperature prediction model, the cooling water amount of the cooling device 20 on the downstream side of the thermometer 14 is reset, and the cooling water amount sprayed on each cut plate in the cooling device 20 on the downstream side of the thermometer 14 is set. The cooling stop temperature can be controlled with high accuracy by changing to the reset one.
On the other hand, in the comparative example, the error between the predicted value of the cooling stop temperature and the measured value was 50 ° C. From this result, it can be seen that according to the present invention, the cooling stop temperature can be controlled with high accuracy.

  Furthermore, the above-described processing was performed on a plurality of thick steel plates, and the prediction accuracy of the cooling stop temperature (difference between the predicted value of the cooling stop temperature and the measured value = stop temperature prediction error) was compared. Table 1 shows the results when the cooling stop target temperature is 500 ° C. or higher and the results when the cooling stop target temperature is expanded to 400 ° C. or higher.

As shown in Table 1, when the cooling stop target temperature was set to 500 ° C. or higher, the standard deviation σ was 16.4 ° C. in the comparative example, and the average value of the stop temperature prediction error was −4.6 ° C. However, in the present invention, the standard deviation σ is 11.6 ° C., and the average value of the stop temperature prediction error is improved to 2.2 ° C. Further, as shown in Table 1, when the cooling stop target temperature is expanded to 400 ° C. or higher, the standard deviation σ is 18.9 ° C. in the comparative example, and the average value of the stop temperature prediction error is −2.1. In the present invention, the standard deviation σ was 14.8 ° C., and the average value of the stop temperature prediction error was improved to 1.3 ° C.
From these results, it was found that according to the present invention, the cooling stop temperature can be controlled with high accuracy for a thick steel plate having a wide range of cooling stop temperatures.

DESCRIPTION OF SYMBOLS 1 ... Thick steel plate 10 ... Rolling mill 11 ... Incoming thermometer 12, 13, 14 ... Thermometer in cooling device 15 ... Outlet thermometer 20 ... Cooling device 30, 40 ... Cooling control device for thick steel plate 31 ... First cut Plate temperature prediction unit 32, 42 ... first cooling water amount setting unit 33, 43 ... adjustment unit 34 ... second cut plate temperature prediction unit 35, 45 ... second cooling water amount setting unit 41 ... first temperature prediction unit 44 ... second Temperature prediction unit 100, 200 ... Thick steel plate manufacturing apparatus

Claims (10)

Cooling is performed by spraying cooling water on the transported thick steel plate after hot rolling, and a cooling device capable of operating the cooling water amount so that the temperature of the thick steel plate after cooling becomes a predetermined temperature,
Predicting the temperature of the thick steel plate after cooling using a steel plate temperature prediction model, deriving a cooling water amount at which the predicted steel plate temperature becomes a predetermined temperature, and cooling the thick steel plate with the derived cooling water amount, A method for controlling cooling comprising:
Using a thermometer installed on the inlet side of the cooling device, measuring the temperature of the thick steel plate when passing through the thermometer, a first temperature measurement step,
First temperature prediction step of predicting the temperature of the thick steel plate using the steel plate temperature prediction model, starting from the temperature measured in the first temperature measurement step,
A first cooling water amount that sets the cooling water amount of the entire cooling device for lowering the temperature of the thick steel plate on the outlet side of the cooling device, predicted in the first temperature prediction step, to a cooling stop target temperature. A setting process;
A first cooling step of cooling the thick steel plate by blowing the cooling water of the cooling water amount set in the first cooling water amount setting step onto the thick steel plate;
Using a thermometer installed in the cooling device, measuring the temperature of the thick steel plate when passing through the thermometer, a second temperature measurement step;
The predicted value of the temperature of the thick steel plate at the thermometer position in the cooling device predicted in the first temperature prediction step and the measured value of the temperature of the thick steel plate measured in the second temperature measurement step are An adjustment step of adjusting the steel sheet temperature prediction model to match,
A second temperature prediction step of predicting the temperature of the thick steel plate in a region downstream of the thermometer position in the cooling device using the steel plate temperature prediction model adjusted in the adjustment step;
A region downstream of the thermometer position in the cooling device for reducing the temperature of the steel plate on the outlet side of the cooling device to the cooling stop target temperature predicted in the second temperature prediction step A second cooling water amount setting step of resetting the cooling water amount of the cooling device in
2nd cooling which cools the said thick steel plate by spraying the cooling water of the amount of cooling water set at the said 2nd cooling water amount setting process to the said thick steel plate downstream from the thermometer position in the said cooling device. Process,
A method for controlling cooling of a thick steel plate. The steel sheet temperature prediction model is:
A heat transfer coefficient calculator that calculates the heat transfer coefficient of the nucleate boiling region, the heat transfer coefficient of the transition boiling region, and the heat transfer coefficient of the film boiling region of the thick steel plate surface cooled by the cooling water;
A transition temperature between the nucleate boiling region and the transition boiling region, and a transition temperature calculating unit that calculates a transition temperature between the transition boiling region and the film boiling region,
The adjustment of the steel sheet temperature prediction model in the adjustment step includes the transition temperature between the nucleate boiling region and the transition boiling region, the transition temperature between the transition boiling region and the film boiling region, the heat transfer coefficient of the nucleate boiling region, And the cooling control method of the thick steel plate of Claim 1 performed by correcting the heat transfer rate of the said transition boiling area | region. Cooling is performed by spraying cooling water on the transported thick steel plate after hot rolling, and a cooling device capable of operating the cooling water amount so that the temperature of the thick steel plate after cooling becomes a predetermined temperature,
Predicting the temperature of the thick steel plate after cooling using a steel plate temperature prediction model, deriving a cooling water amount at which the predicted steel plate temperature becomes a predetermined temperature, and cooling the thick steel plate with the derived cooling water amount, A method for controlling cooling comprising:
Considering the thick steel plate as an aggregate of a plurality of cut plates virtually divided in the longitudinal direction,
Using a thermometer installed on the inlet side of the cooling device, measuring the temperature of each cut plate when passing through the thermometer, a first cut plate temperature measuring step;
Starting from the temperature measured in the first cut plate temperature measurement step, predicting the temperature of each cut plate using the steel plate temperature prediction model, a first cut plate temperature prediction step;
Setting the cooling water amount of the entire cooling device for reducing the temperature of each cutting plate on the outlet side of the cooling device predicted in the first cutting plate temperature prediction step to a cooling stop target temperature; 1 cooling water amount setting step;
A first cooling step of cooling each of the cut plates by blowing the cooling water of the amount of cooling water set in the first cooling water amount setting step onto each of the cut plates;
Using a thermometer installed in the cooling device, measuring the temperature of each of the cutting plates when passing through the thermometer, a second cutting plate temperature measurement step;
The predicted value of the temperature of each cutting plate at the thermometer position in the cooling device predicted in the first cutting plate temperature prediction step, and each cutting plate measured in the second cutting plate temperature measurement step. An adjustment step of adjusting the steel sheet temperature prediction model for each of the cut plates so that the measured value of the temperature matches,
Using the steel plate temperature prediction model adjusted in the adjustment step, a second cut plate temperature prediction step of predicting the temperature of each cut plate in a region downstream from the thermometer position in the cooling device;
Downstream of the thermometer position in the cooling device for reducing the temperature of each cutting plate on the outlet side of the cooling device, predicted in the second cutting plate temperature prediction step, to the cooling stop target temperature. A second cooling water amount setting step for resetting the cooling water amount of the cooling device for each of the cut plates in the region on the side;
By blowing the cooling water of the cooling water amount set in the second cooling water amount setting step onto the respective cutting plates on the downstream side of the thermometer position in the cooling device, the respective cutting plates are cooled every moment. A second cooling step;
A method for controlling cooling of a thick steel plate. The steel sheet temperature prediction model is:
A heat transfer coefficient calculator for calculating the heat transfer coefficient of the nucleate boiling area, the heat transfer coefficient of the transition boiling area, and the heat transfer coefficient of the film boiling area of each of the cut plate surfaces cooled by the cooling water;
A transition temperature between the nucleate boiling region and the transition boiling region, and a transition temperature calculating unit that calculates a transition temperature between the transition boiling region and the film boiling region,
The adjustment of the steel sheet temperature prediction model in the adjustment step includes the transition temperature between the nucleate boiling region and the transition boiling region, the transition temperature between the transition boiling region and the film boiling region, the heat transfer coefficient of the nucleate boiling region, And the cooling control method of the thick steel plate of Claim 3 performed by correcting the heat transfer rate of the said transition boiling area | region. Hot rolling a thick steel plate;
Cooling the thick steel plate after the hot rolling step,
The manufacturing method of a thick steel plate in which the cooling control method of the thick steel plate according to any one of claims 1 to 4 is used in the cooling step. A cooling control device for controlling operating conditions of a cooling device for cooling hot-rolled thick steel plates,
Thermometers installed on the inlet side and the outlet side of the cooling device and in the cooling device, and
Measured using a thermometer installed on the inlet side of the cooling device, starting from the temperature of the thick steel plate when passing through the thermometer, using a steel plate temperature prediction model, the inlet side of the cooling device A first temperature prediction unit that predicts the temperature of the thick steel plate in a region downstream of the position of the thermometer installed in
The amount of cooling water in the entire cooling device for reducing the temperature of the steel plate at the position of the thermometer installed on the outlet side of the cooling device predicted by the first temperature prediction unit to the cooling stop target temperature A first cooling water amount setting unit,
Measured using the predicted value of the temperature of the steel plate at the position of the thermometer installed in the cooling device, predicted by the first temperature prediction unit, and the thermometer installed in the cooling device. Adjusting the steel sheet temperature prediction model so that the measured value of the temperature of the thick steel sheet matches, an adjustment unit;
A second temperature prediction unit that predicts a temperature of the thick steel plate in a region downstream of a position of a thermometer installed in the cooling device, using the steel plate temperature prediction model adjusted by the adjustment unit;
Installed in the cooling device for reducing the temperature of the thick steel plate at the position of the thermometer installed on the outlet side of the cooling device, predicted by the second temperature prediction unit, to the cooling stop target temperature. A second cooling water amount setting unit for resetting the cooling water amount of the cooling device in a region downstream of the position of the thermometer,
A thick steel plate cooling control device. The steel sheet temperature prediction model is:
A heat transfer coefficient calculator that calculates the heat transfer coefficient of the nucleate boiling region, the heat transfer coefficient of the transition boiling region, and the heat transfer coefficient of the film boiling region of the thick steel plate surface cooled by the cooling water;
A transition temperature between the nucleate boiling region and the transition boiling region, and a transition temperature calculating unit that calculates a transition temperature between the transition boiling region and the film boiling region,
The adjustment of the steel sheet temperature prediction model in the adjustment unit includes the transition temperature between the nucleate boiling region and the transition boiling region, the transition temperature between the transition boiling region and the film boiling region, the heat transfer coefficient of the nucleate boiling region, And the cooling control apparatus of the thick steel plate of Claim 6 performed by correcting the heat transfer rate of the said transition boiling area | region. A cooling control device for controlling operating conditions of a cooling device for cooling hot-rolled thick steel plates,
The thick steel plate is regarded as an assembly of a plurality of cut plates virtually divided in the longitudinal direction,
Thermometers installed on the inlet side and the outlet side of the cooling device and in the cooling device, and
Measured using a thermometer installed on the inlet side of the cooling device, starting from the temperature of each cut plate when passing through the thermometer, using a steel plate temperature prediction model, the inlet side of the cooling device A first cut plate temperature prediction unit that predicts the temperature of each cut plate in a region downstream of the position of the thermometer installed in
The entire cooling device for reducing the temperature of each cutting plate at the position of the thermometer installed on the outlet side of the cooling device, predicted by the first cutting plate temperature prediction unit, to the cooling stop target temperature A first cooling water amount setting unit for setting the cooling water amount of
Using the predicted value of the temperature of each cut plate at the position of the thermometer installed in the cooling device, predicted by the first cut plate temperature prediction unit, and the thermometer installed in the cooling device An adjustment unit that adjusts the steel sheet temperature prediction model so that the measured value of the temperature of each cut plate matches the measured value,
Using the steel plate temperature prediction model adjusted by the adjustment unit, a second cut plate temperature prediction that predicts the temperature of each cut plate in a region downstream from the position of the thermometer installed in the cooling device. And
In the cooling device for reducing the temperature of each cutting plate at the position of the thermometer installed on the outlet side of the cooling device predicted by the second cutting plate temperature prediction unit to the cooling stop target temperature A second cooling water amount setting unit for resetting the cooling water amount of the cooling device for each of the cut plates in a region downstream of the position of the thermometer installed in
A thick steel plate cooling control device. The steel sheet temperature prediction model is:
A heat transfer coefficient calculator for calculating the heat transfer coefficient of the nucleate boiling area, the heat transfer coefficient of the transition boiling area, and the heat transfer coefficient of the film boiling area of each of the cut plate surfaces cooled by the cooling water;
A transition temperature between the nucleate boiling region and the transition boiling region, and a transition temperature calculating unit that calculates a transition temperature between the transition boiling region and the film boiling region,
The adjustment of the steel sheet temperature prediction model in the adjustment unit includes the transition temperature between the nucleate boiling region and the transition boiling region, the transition temperature between the transition boiling region and the film boiling region, the heat transfer coefficient of the nucleate boiling region, And the cooling control apparatus of the thick steel plate of Claim 8 performed by correcting the heat transfer coefficient of the said transition boiling area | region. A rolling mill for hot rolling the thick steel plate, a cooling device for cooling the thick steel plate hot rolled by the rolling mill, and a cooling control device for controlling the operation of the cooling device,
The 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 6 to 9.