JP7201126B2 - Hot rolling line controller - Google Patents

Description

The present disclosure relates to a controller for a hot rolling line.

Patent Literature 1 discloses a control device for a hot rolling line. According to the control device, it is possible to suppress destabilization of cooling in the transition boiling region.

Japanese Patent No. 4894686

However, in the control device described in Patent Document 1, the feedback bank close to the winding thermometer is removed. As a result, the response performance of feedback control of the winding temperature is degraded.

The present disclosure has been made to solve the above problems. An object of the present disclosure is to provide a control device for a hot rolling line that can suppress destabilization of cooling in the transition boiling region while maintaining response performance of feedback control of the coiling temperature.

A control device for a hot rolling line according to the present disclosure is a hot rolling line in which a rolled material rolled by a finishing mill is cooled by pouring water with an ROT cooling device and then wound with a winding coiler. a feedforward correction value calculation unit that calculates a correction value based on the deviation between the target value and the actual measurement value of the coiling temperature of the rolled material with respect to the reference value of the target temperature of the rolled material in the feedforward control of the upstream bank; , a feedback correction value for calculating a correction value according to the correction value calculated by the feedforward correction value calculation unit with respect to the reference value of the cooling water amount to the rolled material in the feedback control of the downstream bank in the ROT cooling device and a calculation unit that corrects the reference value of the target temperature of the rolled material in the feedforward control of the upstream bank by the correction value calculated by the feedforward correction value calculation unit, and then corrects the target temperature of the rolled material by the upstream bank. After controlling the cooling and correcting the reference value of the amount of cooling water to the rolled material in the feedback control of the bank on the downstream side by the correction value calculated by the feedback correction value calculation unit, the feedback control of the bank on the downstream side is performed. and a control unit for controlling cooling of the rolled material.

According to the present disclosure, the control device controls the cooling of the rolled material by the upstream bank after correcting the reference value of the target temperature of the rolled material in the feedforward control of the upstream bank with the correction value. The control device corrects the reference value of the amount of cooling water to the rolled material in the feedback control of the bank on the downstream side by the correction value calculated by the feedback correction value calculation unit, and then corrects the amount of the rolled material by the feedback control of the bank on the downstream side. Control cooling. Therefore, it is possible to suppress destabilization of cooling in the transition boiling region while maintaining the response performance of feedback control of the winding temperature.

1 is a configuration diagram of a main part of a hot rolling line to which a hot rolling line control device according to Embodiment 1 is applied; FIG. FIG. 4 is a diagram showing a history of temperature drop of a rolled material in a hot rolling line to which the hot rolling line control device in Embodiment 1 is applied; FIG. 4 is a diagram for explaining a heat flux due to water cooling of a hot rolling line to which the hot rolling line control device according to the first embodiment is applied; 1 is a perspective view of a cut plate to which a control device for a hot rolling line according to Embodiment 1 is applied; FIG. FIG. 2 is a block diagram of main parts of the control device for the hot rolling line according to Embodiment 1. FIG. FIG. 4 is a diagram showing a predicted temperature value of a cut sheet calculated by the controller of the hot rolling line in Embodiment 1; FIG. 4 is a diagram for explaining non-interference between two feedback controls by the hot rolling line control device in Embodiment 1; FIG. 5 is a diagram for explaining a method of adding most of the cooling water amount of the most downstream bank to other bank groups by the control device for the hot rolling line in Embodiment 1; The operation of the hot rolling line control device according to the first embodiment will be described. 2 is a hardware configuration diagram of a control device for a hot rolling line according to Embodiment 1. FIG. FIG. 10 is a block diagram of main parts of a control device for a hot rolling line according to Embodiment 2;

Embodiments will be described with reference to the accompanying drawings. In addition, the same code|symbol is attached|subjected to the part which is the same or corresponds in each figure. Redundant description of the relevant part will be simplified or omitted as appropriate.

Embodiment 1.
FIG. 1 is a configuration diagram of a main part of a hot rolling line to which a hot rolling line control device according to Embodiment 1 is applied.

In the hot rolling line of FIG. 1, a finishing mill 1 is provided downstream of a roughing mill (not shown). The ROT cooling device 2 is provided downstream of the finishing mill 1 . A pinch roll 3 is provided downstream of the ROT cooling device 2 . The winding coiler 4 is provided downstream of the pinch rolls 3 .

The ROT cooling device 2 includes a water injection device. In the ROT cooling device 2, the water injection device is divided into a plurality of banks in the cooling water supply system. A plurality of banks are arranged in the length direction of the hot rolling line. Each of the multiple banks includes multiple water injection valves. A plurality of water injection valves are aligned along the length of the hot rolling line. A plurality of nozzles are provided for each of the plurality of water injection valves. A plurality of nozzles are arranged in the width direction of the hot rolling line.

A finishing mill delivery side thermometer 5 is provided between the finishing mill 1 and the ROT cooling device 2 . A winding thermometer 6 is provided between the ROT cooling device 2 and the pinch rolls 3 .

The finish rolling mill 1 finish-rolls a rolled material. After that, the finishing mill delivery side thermometer 5 measures the initial temperature of the entire length of the rolled material before cooling as the FDT actual value. Thereafter, the ROT cooling device 2 cools the rolled material by injecting water at a constant pressure. After that, the winding thermometer 6 measures the initial temperature of the entire length of the rolled material as a CT actual value. After that, the winding coiler 4 winds up the rolled material. The position of the rolled stock is tracked based on the peripheral speed v _FM7 of the final stand of the finishing mill 1 and the peripheral speed v _pc of the winding coiler 4 which determine the line speed.

The control device 7 includes a storage section 7a, a feedforward correction value calculation section 7b, a feedback correction value calculation section 7c, and a control section 7d.

The control unit 7 controls the ROT cooling device 2 for each cut plate using the temperature model so that the final CT prediction value reaches the target value with the FDT actual value of the cut plate k as a starting point by the control unit 7d. Calculate the predicted value of the temperature at the input and output sides of each bank. At this time, half of the water injection valves are opened in advance in the bag on the most downstream side.

When the final CT prediction value does not match the target value, the control device 7 updates the setting value of the cooling water amount in each upstream bank other than the most downstream bank, and then updates the ROT cooling device 2 for each cutting plate. Calculate the predicted value of the temperature at the input and output sides of each bank.

When the final CT prediction value matches the target value, the control device 7 sets the set value of the cooling water amount in each bank on the upstream side other than the most downstream bank as the reference value V _k ^FF_ref .

On the upstream side, except for the most downstream bank, each bank cools each cutting plate by determining the number of water injection valves to open so that the amount of cooling water meets the reference value V _k ^FF_ref .

In FIG. 1, the first to fifth upstream banks are used for cutting plate k. In this case, the control device 7 causes the feedforward correction value calculation unit 7b to calculate the target value CT ^cmd of the winding temperature and the measured value CT _A correction value ΔCT _k ^aim based on the deviation from ka ^act is calculated. The controller 7 calculates the target value CT _k ^aim of the temperature model using the following equation (1).

For the cutting plate kb, the control device 7 causes the feedback correction value calculation unit 7c to calculate the feedforward correction value for the reference value V ^{kb 2nd_ref} _of the cooling water amount to the rolled material in the feedback control of the bank on the downstream side. A correction value ΔV _k−b ^2nd_ref is calculated according to the correction value ΔCT _k ^aim calculated by the calculator 7b.

Each time the cut sheet passing directly under the winding thermometer 6 changes, the correction value ^ΔCT _k ^aim and the correction value ΔV _{kb 2nd_ref} change based on the actual measurement value CT ka ^act of the winding temperature.

The control device 7 stores the information of the actual value V _k ^1st_act of the cooling water amount of the bank that is the most downstream among the banks used in the banks other than the most downstream in the storage unit 7a.

The control device 7 causes the control unit 7d to correct the reference value of the target temperature in the feedforward control of the upstream bank by the correction value ΔCT _k ^aim calculated by the feedforward correction value calculation unit 7b, and then corrects the target temperature reference value to the upstream bank. controls the cooling of each cut plate by

When each cut plate reaches the bank on the downstream side, the control device 7 calculates the reference value V _k−b ^2nd_ref of the cooling water amount to the cut plate in the feedback control of the most downstream bank as a feedback correction value by the control unit 7d. The reference value V _k−b ^2nd_ref_mod corrected according to the correction value ΔV _k−b ^2nd_ref calculated by the unit 7c controls the cooling of each cut plate by feedback control of the most downstream bank. At this time, as the correction value ΔV _k−b ^2nd_ref , the actual value V _k ^1st_act of the amount of cooling water for each cut plate may be adopted.

Next, the history of the temperature drop of the rolled material will be described with reference to FIG.
FIG. 2 is a diagram showing the history of temperature drop of the rolled strip in the hot rolling line to which the hot rolling line control device in the first embodiment is applied.

As shown in FIG. 2, for each bank, the interval of the water injection valve that opens is adjusted so as to satisfy the preset cooling rate set value in consideration of the material of the rolled material.

Next, the heat flux due to water cooling will be described with reference to FIG.
FIG. 3 is a diagram for explaining the heat flux due to water cooling of the hot rolling line to which the hot rolling line control device according to the first embodiment is applied.

As shown in FIG. 3, when the surface of the rolled material is film boiling, water vapor exists between the surface of the rolled material and the cooling water. When the temperature of the surface of the rolled material decreases, the surface of the rolled material shifts from the film boiling state to the transition boiling state. When the temperature of the surface of the rolled material is further lowered, the surface of the rolled material shifts from the state of transition boiling to the state of nucleate boiling. In the state of nucleate boiling on the surface of the rolled material, the entire upper surface of the rolled material is in contact with the cooling water. As a result, vapor bubbles are generated locally.

When the surface of the rolled material is in a state of transition boiling, the heat flux is smaller in the portion where the temperature is high at the start of cooling than in the portion where the temperature is low. This delays cooling. On the other hand, the low temperature portion has a large heat flux. This facilitates cooling. As a result, the temperature difference increases between the high-temperature portion and the low-temperature portion at the start of cooling.

As long as the surface of the rolled material is cooled in the state of transition boiling, the local temperature unevenness is accumulated and enlarged. As a result, in the steel sheet after cooling, material unevenness such as poor flatness, residual stress, hardness distribution, and strength distribution may occur.

Next, the concept of the temperature model will be explained using FIG.
FIG. 4 is a perspective view of a cut sheet to which the hot rolling line control device in Embodiment 1 is applied.

As shown in FIG. 4, when the rolled material is conveyed directly under the ROT cooling device 2, heat input/output is calculated after virtually dividing the rolled material into cut plates of a certain length. For example, the fixed length is set between 3m and 5m.

Factors for heat input/output include water cooling heat transfer, radiation, heat generation due to phase transformation, and the like. For example, when water-cooling heat transfer is the only factor, the amount of heat removed by water-cooling Q _water (W) is expressed by the following equation (2).

In equation (2), hw is the water cooling heat transfer coefficient ( _W /mm ² /°C). _Aw is the area (mm ² ) of the top and bottom surfaces of the cutting plate that come into contact with the cooling water. _Aw varies with the number of water injection valves open in each bank. T _surf is the surface temperature of the cut plate (°C). _Tw is the temperature of the cooling water (°C).

Under the present circumstances, the temperature change of each cut plate is represented by following (3) Formula.

In equation (3), ΔT _i is the temperature drop (°C) of cut plate k in bank i. i is the bank number. Δt is the transit time (s) of cutting plate k in bank i. _lk is the length (mm) of the cut plate k in the traveling direction. Hk is the plate thickness (mm) of the cut plate _k . Bk is the width (mm) of the cut plate _k . ρ is the density of the cut plate k (kg/mm ³ ). CP is the specific heat (J/kg/°C) of the _cut plate k.

Next, a method of calculating the correction value ΔCT _k ^aim and the post-correction reference value V _k−b ^2nd_ref_mod will be described with reference to FIG.
FIG. 5 is a block diagram of the essential parts of the control device for the hot rolling line according to the first embodiment.

On the left side of FIG. 5, the PID gain of the first PID controller is set taking into account the transport dead time to the winding thermometer 6 . The first PID controller receives an input of deviation information between the target value CT ^cmd and the measured value CT _ka ^act of the winding temperature. The first PID controller calculates the correction value _{ΔCT k aim} ^by multiplying the deviation between the target value CT ^cmd and the measured value CT ka ^act of the winding temperature by the PID gain.

On the right side of FIG. 5, the PID gain of the second PID controller is set taking into account the transfer dead time to the winding thermometer 6 . The second PID controller receives an input of information of _a value obtained by inverting the sign of the difference between the winding temperature target value CT ^cmd and the actual measurement value CT ka ^act . The second PID controller multiplies the value obtained by inverting the sign of the deviation between the target value CT ^cmd and the actual measurement value CT _k-a ^act of the winding temperature by the PID gain, thereby calculating the reference value V _k-b of the cooling water amount. ^2nd_ref is calculated. The corrected reference value V _k−b ^2nd_ref_mod is calculated by subtracting the actual value V _k ^1st_act from V _k−b ^2nd_ref_mod .

Next, with reference to FIG. 6, predicted values of the temperature of the cut plate in the ROT cooling device 2 will be described.
FIG. 6 is a diagram showing predicted values of the temperature of the cut sheet calculated by the control device for the hot rolling line according to the first embodiment.

FIG. 6 shows the predicted values of the temperature of the cut plate when it is assumed that the speed of passage of the cut plate is constant in one bank. Before the cut plate is cooled, the control device 7 calculates predicted values of the temperature of each cut plate at the entry and exit sides of each bank using equations (2) and (3).

When the FDT performance value changes, the number of banks used in banks other than the most downstream bank changes for each cutting plate. As a result, among the banks used in banks other than the most downstream bank, the most downstream bank also changes.

As shown in FIG. 6, when the correction value ΔCT ^aim is smaller than 0, the set value CT ^aim of the target temperature of the temperature model is smaller than the target value CT ^cmd of the winding temperature. In this case, among the banks used in the banks other than the most downstream bank, the most downstream bank is the bank further downstream.

For example, among the banks other than the most downstream bank, if the current most downstream bank is the fourth bank from the upstream side, opening the water injection valve of the fifth bank from the upstream side, The amount of cooling water increases in banks other than the most downstream bank.

Next, the decoupling of two feedback controls will be described with reference to FIG.
FIG. 7 is a diagram for explaining non-interference between two feedback controls by the hot rolling line control device according to the first embodiment.

When the cutting plate k reaches the entrance side of the bank on the most downstream side, the control device 7 subtracts the actual value V _k ^1st_act from the reference value V _k ^2nd_ref of the amount of cooling water in the bank on the most downstream side.

Next, with reference to FIG. 8, a method of adding most of the cooling water amount of the most downstream bank to other bank groups will be described.
FIG. 8 is a diagram for explaining a method of adding most of the cooling water amount of the most downstream bank to other bank groups by the control device for the hot rolling line in the first embodiment.

After a certain period of time has passed since the start of cooling, _if the reference value V kb _{2nd_ref_mod} of the cooling water amount for the ^{cut plate kb} does not become smaller than a preset threshold in the bank on the most downstream side, the control device 7 sets the cooling water amount A certain percentage (for example, 80%) of the reference value V _k−b ^2nd_ref_mod of is converted into the correction value ΔCT _k−b ^2nd of the target temperature by the temperature model. At this time, the target temperature correction value _ΔCT kb ^2nd is smaller than zero.

The controller 7 corrects the target value CT _k ^aim of the temperature model for the cut plate k using the equation (4).

As a result, the amount of cooling water supplied to the cut plate k in banks other than the most downstream bank increases.

Next, the operation of the control device 7 will be described with reference to FIG.
FIG. 9 explains the operation of the control device for the hot rolling line in the first embodiment.

In step S1, the control device 7 calculates _a correction value ΔCT _k ^aim based on the deviation between the target value CT _cmd of the winding temperature of the cut sheet k and the actual measurement value CT ka ^act . After that, the control device 7 performs the operation of step S2. In step S2, the control device determines whether or not the correction value ΔCT _k ^aim is smaller than zero.

If the correction value is smaller than 0 in step S2, the control device performs the operation of step S3. In step S3, the control device determines the correction value ΔCT _k ^aim .

If the correction value is not less than 0 in step S2, the control device performs the operation of step S4. In step S4, the control device determines whether or not the reference value V _k−b ^2nd_ref of the cooling water amount is zero.

If the reference value of the cooling water amount is not 0 in step S4, the control device performs the operation of step S5. In step S5, the control device sets the correction value ΔCT _k ^aim to zero. After that, the control device determines the correction value in step S3.

If the reference value of the cooling water amount is 0 in step S4, the control device determines the correction value in step S3.

According to the first embodiment described above, the control device 7 corrects the reference value of the target temperature of the rolled material in the feedforward control of the upstream bank with the correction value, and then corrects the target temperature of the rolled material by the upstream bank. Control cooling. The control device 7 corrects the reference value of the amount of cooling water to the rolled material in the feedback control of the bank on the downstream side by the correction value calculated by the feedback correction value calculation unit, and then corrects the rolled material by the feedback control of the bank on the downstream side. control the cooling of the Therefore, it is possible to suppress destabilization of cooling in the transition boiling region while maintaining the response performance of feedback control of the winding temperature.

Further, the control device 7 performs the above control for each of the plurality of cut plates. Therefore, it is possible to more reliably suppress destabilization of cooling in the transition boiling region.

Further, the control device 7 calculates a correction value of the cooling water amount according to the reference value of the target temperature of the rolled material in the feedforward control of the upstream bank from the reference value of the cooling water amount in the feedback control of the bank on the downstream side. Feedback control of the bank on the downstream side is performed so as to obtain the amount of cooling water that has been subtracted. Therefore, it is possible to realize non-interference between the two feedback controls.

Further, when the correction value for the reference value of the target temperature of the rolled material in the feedforward control of the upstream bank is 0 or more, and when the deviation between the target value and the measured value of the coiling temperature of the rolled material is 0 or less, the control device 7 does not correct each reference value. Therefore, it is possible to preferentially reduce the amount of cooling water in the downstream bank used for feedback control.

Further, when the reference value of the cooling water amount does not become smaller than the preset threshold value after a certain period of time has elapsed since the start of cooling, the control device 7 converts a certain percentage of the reference value into a corrected value of the target temperature using the temperature model. . Therefore, the amount of cooling water in the bank on the downstream side used for feedback control can be reduced.

Next, an example of the control device 7 will be described with reference to FIG.
FIG. 10 is a hardware configuration diagram of the control device for the hot rolling line according to the first embodiment.

Each function of the control device 7 can be realized by a processing circuit. For example, the processing circuitry comprises at least one processor 100a and at least one memory 100b. For example, the processing circuitry comprises at least one piece of dedicated hardware 200 .

When the processing circuit comprises at least one processor 100a and at least one memory 100b, each function of the control device 7 is implemented by software, firmware, or a combination of software and firmware. At least one of software and firmware is written as a program. At least one of software and firmware is stored in at least one memory 100b. At least one processor 100a realizes each function of the control device 7 by reading and executing a program stored in at least one memory 100b. The at least one processor 100a is also referred to as a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, DSP. For example, the at least one memory 100b is a nonvolatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, EEPROM, magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD, or the like.

Where the processing circuitry comprises at least one piece of dedicated hardware 200, the processing circuitry may be implemented, for example, in single circuits, multiple circuits, programmed processors, parallel programmed processors, ASICs, FPGAs, or combinations thereof. be. For example, each function of the control device 7 is implemented by a processing circuit. For example, each function of the control device 7 is collectively realized by a processing circuit.

A part of each function of the control device 7 may be realized by dedicated hardware 200 and the other part may be realized by software or firmware. For example, the functions of the control unit 7d are realized by a processing circuit as dedicated hardware 200, and the functions other than the functions of the control unit 7d are read by at least one processor 100a reading a program stored in at least one memory 100b. It may be realized by executing

Thus, the processing circuitry implements each function of the controller 7 in hardware 200, software, firmware, or a combination thereof.

Embodiment 2.
FIG. 11 is a block diagram of main parts of a control device for a hot rolling line according to Embodiment 2. As shown in FIG. The same reference numerals are given to the same or corresponding parts as those of the first embodiment. Description of this part is omitted.

The Smith method is applied in the second embodiment.

In FIG. 11, CT _k ^{pre — 1st} is the predicted value of the current coiling temperature of the cut strip k directly below the finishing mill delivery side thermometer 5 . CT _k ^pre — 1st is a predicted value of the coiling temperature calculated when the cut strip ka is directly below the finishing mill delivery side thermometer 5 . CT ^{kb pre} _— 2nd is the predicted value of the winding temperature of the cut plate kb when the cut plate kb reaches the entry side of the bank on the most downstream side. CT ka pre _— ^2nd is a predicted value of the winding temperature of the cut sheet ka calculated when the cut sheet ka reaches the entry side of the bank on the most downstream side. Information on these predicted values is stored in the storage unit 7 a of the control device 7 .

As shown on the left side of FIG. 11, CT _k ^{pre — 1st} without dead time is input in the inner feedback loop. In the outer feedback loop, the deviation between CT ^{ka act} and CT _{ka pre_1st} is input as the model prediction error. A correction value ΔCT _k ^aim is calculated based on these inputs.

As shown on the right side of FIG. 11, in the inner feedback loop, CT _k−b ^pre — 2nd without dead time is input. In the outer feedback loop, the deviation between CT ^{ka act} and CT _{ka pre_2nd} is input as the model prediction error. A reference value V _k−b ^2nd_ref is calculated based on these inputs.

According to the second embodiment described above, the Smith method is applied. Therefore, the control gain can be increased.

As described above, the hot rolling line control device of the present disclosure can be used in a hot rolling line.

1 finishing rolling mill, 2 ROT cooling device, 3 pinch rolls, 4 winding coiler, 5 finishing rolling mill outlet thermometer, 6 winding thermometer, 7 control device, 7a storage unit, 7b feedforward correction value calculation unit, 7c feedback correction value calculator 7d controller 100a processor 100b memory 200 hardware

Claims (6)

In a hot rolling line in which a rolled material rolled by a finishing mill is cooled by water injection by an ROT cooling device and then wound by a winding coiler, the target of the rolled material in the feedforward control of the upstream bank in the ROT cooling device a feedforward correction value calculation unit that calculates a correction value based on a deviation between a target value and an actual measurement value of the coiling temperature of the rolled material with respect to the reference value of the temperature;
Feedback correction value calculation for calculating a correction value according to the correction value calculated by the feedforward correction value calculation unit with respect to the reference value of the cooling water amount to the rolled material in the feedback control of the bank on the downstream side in the ROT cooling device Department and
After correcting the reference value of the target temperature of the rolled material in the feedforward control of the upstream bank with the correction value calculated by the feedforward correction value calculation unit, the cooling of the rolled material by the upstream bank is controlled. Cooling of the rolled material by feedback control of the downstream bank after correcting the reference value of the amount of cooling water to the rolled material in the feedback control of the downstream bank by the correction value calculated by the feedback correction value calculation unit. a control unit that controls
A control device for a hot rolling line with The feedforward correction value calculation unit calculates a correction value based on the deviation between the target value and the actual measurement value of the coiling temperature with respect to the reference value of the target temperature of each of a plurality of cut plates obtained by virtually dividing the rolled material. calculate,
The feedback correction value calculation unit calculates a correction value corresponding to the correction value calculated by the feedforward correction value calculation unit with respect to the reference value of the amount of cooling water for each of the plurality of cut plates,
For each of the plurality of cut plates, the control unit corrects the reference value of the target temperature in the feedforward control of the upstream bank by the correction value calculated by the feedforward correction value calculation unit, and After controlling the cooling by the upstream bank and correcting the reference value of the cooling water amount in the feedback control of the downstream bank according to the correction value calculated by the feedback correction value calculation unit, 2. The control device for a hot rolling line according to claim 1, wherein the cooling is controlled by feedback control. The control unit subtracts the correction value of the cooling water amount according to the correction value calculated by the feedforward correction value calculating unit from the reference value of the cooling water amount in the feedback control of the downstream bank so that the cooling water amount is obtained. 3. The control device for a hot rolling line according to claim 1 or 2, wherein the downstream bank is feedback-controlled. When the correction value calculated by the feedforward correction value calculation unit is 0 or more and when the deviation between the target value and the measured value of the coiling temperature of the rolled material is 0 or less, the control unit controls the upstream bank Control the cooling by the upstream bank without correcting the reference value of the target temperature of the rolled material in the feedforward control by the correction value calculated by the feedforward correction value calculation unit, and feedback the downstream bank Controlling the cooling of the bank on the downstream side by feedback control without correcting the reference value of the amount of cooling water to the rolled material in the control according to the correction value calculated by the feedback correction value calculating section. 4. The hot rolling line control device according to any one of 3. When the reference value of the amount of cooling water does not become smaller than a preset threshold value after a certain period of time has passed since the start of cooling, the control unit converts a certain percentage of the reference value into a correction value of the target temperature using a temperature model, 5. The cooling of the rolled material by the upstream bank is controlled after correcting a reference value of the target temperature of the rolled material in the feedforward control of the upstream bank with the correction value. 1. A control device for a hot rolling line according to item 1. The feedforward correction value calculation unit receives an input of a predicted value of the winding temperature that does not include dead time in the inner feedback loop, and receives an input of the deviation between the actual value and the predicted value of the winding temperature in the outer feedback loop. Receive, based on these inputs, calculate a correction value for the reference value of the target temperature of the rolled material in the feedforward control of the upstream bank,
The feedback correction value calculation unit receives an input of a predicted winding temperature value that does not include dead time in the inner feedback loop, and receives an input of the deviation between the actual winding temperature value and the predicted value in the outer feedback loop. 6. The control device for a hot rolling line according to any one of claims 1 to 5, which calculates a reference value for the amount of cooling water to be supplied to the rolling material in the feedback control of the bank on the downstream side based on these inputs. .

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