JP2006272395A - Method and apparatus for controlling cooling and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform high-accuracy dynamic control and to reduce effect to impartation of required quality to the product. <P>SOLUTION: The cooling control apparatus 100 controls a cooling apparatus 4 which cools a steel sheet 1 with the volume of cooling water so that cooling strength is fixed during cooling and threading while conveying the steel sheet after finish rolling. A sheet passing speed is calculated in accordance with the target cooling finish temperature information and used by the cooling apparatus 4 and also this apparatus is provided with a predetermined cooling history obtaining part 101 for obtaining the predetermined cooling history of the steel sheet 1 with the cooling apparatus 4, an actual intermediate temperature information obtaining part 102 for obtaining an actual intermediate temperature information in a prescribed portion in the longitudinal direction of the steel sheet in the actual intermediate position M of the cooling apparatus 4 and, on the basis of the predetermined cooling history obtained by the predetermined cooling history obtaining part 101 and the actual intermediate temperature information obtained by the actual intermediate temperature information obtaining part 102 and a sheet passing speed correcting part 103 for correcting the sheet passing speed which is used by the cooling apparatus 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cooling control method, apparatus, and computer program for controlling a cooling device for cooling a hot-rolled steel sheet.

  A steel plate production line is operating in which hot rolled steel plates are accelerated and cooled by water cooling to obtain a quenching effect. This cooling of hot-rolled steel sheet is one of the important processes in building the material of the steel sheet, and the parameters that determine its characteristics are mainly “cooling start temperature of steel sheet”, “cooling strength”, “ Cooling end temperature ".

  By the way, among the parameters described above, the “cooling start temperature of the steel sheet” is determined by the finishing temperature of the finish rolling process, and the “cooling strength” is determined as a precondition for building a desired material. In the cooling control, the “cooling end temperature of the steel sheet” is the most important.

  Conventionally, the temperature of the steel plate in the cooling plate is measured, and the cooling error amount is corrected by changing the amount of cooling water sprayed on the upper and lower surfaces of the steel plate so that the cooling end temperature becomes the desired temperature. Control has been proposed (for example, Patent Document 1).

Japanese Patent Publication No. 7-41303 JP 2003-138318 A JP-A-6-71315

  However, since a large amount of cooling water is used in the cooling device, there is a problem that if the amount of cooling water is varied in the cooling plate, the response is inferior and high-precision dynamic control is difficult.

  In addition, changing the amount of cooling water in the cooling plate changes the “cooling strength”, which is one of the important parameters, and there is a concern about the influence on the material build-up.

  The present invention has been made in view of the above points, and an object of the present invention is to enable high-precision dynamic control and to reduce the influence on material fabrication.

The cooling control method of the present invention is a cooling control method for controlling a cooling device that cools with a cooling water amount such that the cooling strength is substantially constant during cooling through plate while conveying the steel sheet after finish rolling, It is characterized in that the sheet passing speed of the steel sheet is controlled based on the actual intermediate temperature information of the steel sheet at the intermediate position of the cooling device.
The cooling control device of the present invention is a cooling control device that controls a cooling device that cools with a cooling water amount such that the cooling strength is substantially constant during cooling through plate while conveying the steel plate after finish rolling, It is characterized in that a means for controlling the sheet passing speed of the steel sheet is provided based on the actual intermediate temperature information of the steel sheet at the intermediate position of the cooling device.
The computer program of the present invention is a computer program for controlling a cooling device that cools with a cooling water amount such that the cooling strength is substantially constant during cooling through plate while conveying the steel sheet after finish rolling. Based on the actual intermediate temperature information of the steel sheet at the intermediate position of the cooling device, the present invention is characterized in that a process for controlling the sheet passing speed of the steel sheet is executed by a computer.

  According to the present invention, the amount of cooling water is controlled so that the cooling strength is constant during the cooling plate, and the plate passing speed is controlled so that the cooling end temperature of the steel plate becomes the target cooling end temperature. High-precision dynamic control with excellent responsiveness is possible, and the influence on material fabrication can be reduced.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an example of a steel sheet production line to which the present invention is applied. As shown in the figure, a finishing mill 2 that rolls a steel plate 1 that is roughly formed through a heating furnace or a roughing mill (not shown) to a target plate thickness, and a straightening machine that corrects the shape of the steel plate 1 after finish rolling. 3 and a cooling device 4 for accelerating and cooling the straightened steel plate 1 are sequentially disposed, and the steel plate 1 after the accelerated cooling becomes a product having a desired shape and material.

  A finish front surface thermometer 5 and a finish rear surface thermometer 6 are respectively disposed at the front surface position and the rear surface position of the finish rolling mill 2. An intermediate position thermometer 7 is disposed at the intermediate position M of the cooling device 4. In the present embodiment, an example in which each thermometer measures the surface temperature on the upper surface of the steel plate 1 will be described. However, for example, the surface temperature may be measured on both the upper surface and the lower surface of the steel plate 1.

  FIG. 2 is a diagram illustrating an internal configuration example of the cooling device 4. Inside the cooling device 4, many roller groups 41 which convey the steel plate 1 are arranged, and many nozzle groups (not shown) which inject cooling water to the upper surface and the lower surface of the steel plate 1 are arranged in each of the cooling zones 1Z to 19Z. Is done. The cooling water injection from these nozzle groups is controlled by flow control valves, respectively, and the number of use zones and the injection amount from each nozzle can be adjusted according to various conditions such as the plate thickness and plate length of the steel plate. In the illustrated example, the intermediate position thermometer 7 is disposed between the cooling zones 1Z to 7Z and the cooling zones 8Z to 11Z (intermediate position M).

  FIG. 3 is a diagram illustrating a schematic configuration of a control system including the cooling control device 100 of the present embodiment. The cooling control device 100 includes a rolling control device 200 that performs overall control of each rolling mill including the finish rolling mill 2, a production management device 300 that mainly performs production management, and various types of output that are output from the cooling control device 100. A data input / output device 400 that displays data or outputs an input from an operator to the cooling control device 100 and the intermediate position thermometer 7 are connected.

  Further, the cooling control device 100 is driven when the steel sheet 1 is conveyed, and the cooling water amount control device 500 that controls the flow rate control valve 501 of each cooling zone 1Z to 19Z of the cooling device 4 to control the cooling water amount. A plate feed speed controller 600 that controls the plate feed speed by controlling the steel plate feed motor 601 of the cooling device 4 is connected.

  That is, the cooling control device 100 is based on data input from the intermediate position thermometer 7, the rolling control device 200, the production management device 300, the data input / output device 400, etc. The amount of cooling water and the plate passing speed are controlled via the device 600.

  In particular, the cooling control device 100 of the present embodiment controls the water injection amount of the cooling device by transmitting the required cooling water amount to the cooling water amount control device 500 while conveying the steel sheet 1 after finish rolling, and the cooling device 4, the sheet passing speed is controlled via the sheet passing speed control device 600 based on the actual intermediate temperature information of the steel sheet 1 at the intermediate position M.

  More specifically, the cooling control device 100 according to the present embodiment calculates the plate passing speed according to the target cooling end temperature information and reflects it in the cooling device 4, and acquires the scheduled cooling history of the steel plate 1 by the cooling device 4. Scheduled cooling history acquisition unit 101, actual intermediate temperature information acquisition unit 102 that acquires actual intermediate temperature information at a predetermined portion in the longitudinal direction of the steel sheet 1 at the intermediate position M of the cooling device 4, and planned cooling history acquisition unit 101 A through-plate speed correcting unit 103 that corrects the through-plate speed reflected in the cooling device 4 based on the planned cooling history acquired by the above and the actual intermediate temperature information acquired by the actual intermediate temperature information acquiring unit 102. .

  FIG. 4 is a flowchart for explaining a cooling control process by the cooling control apparatus 100 of the present embodiment. FIG. 5 is a characteristic diagram showing the relationship between the time from the start of cooling and the temperature of the steel plate 1 (average thickness in the plate thickness direction).

  In step S100, the plate passing speed is calculated according to the target cooling end temperature information and reflected in the cooling device 4, and the scheduled cooling history of the steel plate 1 by the cooling device 4 is acquired. Hereinafter, the process for acquiring the scheduled cooling history in step S100 will be described with reference to FIG.

  First, the cooling start temperature information in each segment in the longitudinal direction of the steel sheet 1 on the entry side (cooling start position) of the cooling device 4 is calculated (step S101).

Specifically, the surface temperature of the steel sheet 1 measured by the finishing back surface thermometer 6 is acquired from the rolling control device 200, and the temperature distribution in the sheet thickness direction in each segment at the end of finishing rolling is obtained. As a method for obtaining the temperature distribution in the plate thickness direction from the surface temperature, the temperature distribution in the plate thickness direction is known to be a parabolic shape having the highest temperature at an intermediate position in the plate thickness direction. What is necessary is just to determine the temperature distribution of the plate | board thickness direction 11 points | pieces using the method (refer FIG. 7). In brief, the upper surface temperature _TF is a measured temperature. The temperature difference ΔT between the upper surface and the plate temperature maximum is expressed by the following equation (1)
ΔT = 33.8−3.63h (−0.0371 + 0.00528h) · T _F (1)
Where ΔT: temperature difference between the upper surface and the plate temperature maximum point, and h: plate thickness. The lower surface temperature T _L is expressed by the following formula (2)
T _L = T _F + K ₁ ξ (ΔT _S con + ΔT _S class) + K ₂ (2)
Where ξ: temperature conversion coefficient obtained by learning, ΔT _S : entrance side temperature upper / lower surface temperature difference obtained by learning, K ₁ , K ₂ : determined by adjustment factors. A radial temperature distribution satisfying the above conditions is determined, and a temperature distribution in the thickness direction is determined. In addition, although a detailed description is omitted, methods for obtaining the temperature distribution in the thickness direction from the surface temperature are disclosed in Patent Documents 2 and 3 and the like, and any method may be used.

And the temperature distribution in the plate thickness direction in each segment at the end of finish rolling is set as an initial value, the above-described 11 points in the plate thickness direction are set as calculation target points, and the temperature transition to the cooling start position of the cooling device 4 is the heat transfer difference. By solving the equation, the plate thickness direction average temperature T0 (hereinafter referred to as “cooling start temperature T0”) at each segment at the cooling start position of the cooling device 4 is calculated as cooling start temperature information. As for the technique for analyzing the temperature transition by solving the differential equation of heat conduction, for example, as disclosed in Patent Document 1, the outline will be described based on the initial temperature distribution state in the thickness direction. Using 11 representative points as calculation target points, the one-dimensional heat conduction difference equation Q (i) _t + Δ _t shown in the following equation (3)
_{= Q (i) t + Δt} · (λ i + 1 -2λ i + λ i-1) / ρ · Δx 2 (i = 1~11)
ΔQ _s
= 4.88 [{(Tg + 273) / 100} ⁴ − {(T (i) +273) / 100} ⁴ ] (i = 1, 11)
= 0 (i = 2 to 10) (3)
Where Q (i) _t : heat content of element i at time t, T (i) _t : same temperature display, Δt: difference calculation step time (= const, 150 msec), ρ: density, λ: element i , Tg: temperature, ΔQ _s : boundary condition, Δx: plate thickness division thickness. In this case, the conversion from the plate temperature T to the heat content Q is
If T> 880, Q = 3.333 + 0.16T
If T ≦ 880, Q = −149.05 + 0.481 · T−1.68 × 10 ⁻⁴ · T ²
And conversion from heat content Q to temperature T (heat content: value obtained by integrating specific heat from 0 ° C. to T),
If Q> 144.13, T = -20.8 + 6.25 × Q
If 0 <Q ≦ 144.13, T = 1431.5−√ (1.162 × 10 ₆ −5.95 × 10 ³ × Q)
And

  In this embodiment, the cooling start temperature T0 is obtained by solving the one-dimensional heat conduction difference equation with the temperature distribution in the thickness direction in each segment at the end of finish rolling as an initial value. A thermometer may be arranged on the entrance side of the slab, and the temperature may be obtained from the temperature measured by the thermometer.

Next, the cooling start temperature T0 obtained in step S101, the amount of cooling water in each of the cooling zones 1Z to 19Z set by the production management device 300 or the like as the manufacturing standard value, and the production management device 300 or the like as the manufacturing standard value. Based on the set target thickness direction average temperature TE ^{* at the} end of cooling (hereinafter referred to as “target cooling end temperature TE ^* ”), the total length of the use zone of the cooling device 4, and the like, The calculation is reflected in the cooling device 4 as the initial plate speed (step S102). In the present embodiment, as a premise of the cooling process, the amount of cooling water in each of the cooling zones 1Z to 19Z, that is, the number of used zones and the amount of injection from each nozzle is controlled so that the cooling intensity is substantially constant during the cooling plate. The

Next, the planned total cooling time te _i ^* (i: segment number) in each segment of the steel sheet 1 is calculated based on the sheet passing speed set in step S102 (step S103).

Next, the scheduled cooling time tcb _i ^* until each segment of the steel sheet 1 reaches the intermediate position M (hereinafter referred to as “scheduled pre-stage cooling time tcb _i ^* ”) based on the sheet passing speed set in step S102. (I: segment number) is calculated (step S104).

Next, the planned sheet thickness direction average temperature TI _i ^* (i: segment number) (hereinafter referred to as “scheduled intermediate temperature TI _i ^* ”) at the intermediate position M in each segment of the steel sheet 1 is used as the planned intermediate temperature information. Calculate (step S105). Also in this case, for example, the temperature transition may be analyzed by solving the heat conduction difference equation in the same manner as calculating the cooling start temperature T0 in step S101 with the cooling start temperature T0 as an initial value.

Next, a planned cooling time tcf _i ^* (hereinafter referred to as “scheduled post-stage cooling time tcf _i ^* ”) until each segment of the steel sheet 1 reaches the cooling end position from the intermediate position M is calculated (i: segment number). (Step S106). The scheduled post-stage cooling time tcf _i ^* can be calculated by subtracting the planned pre-stage cooling time tcb _i ^* calculated in step S104 from the planned total cooling time te _i ^* calculated in step S103.

Then, based on the target cooling end temperature TE ^* , the planned intermediate temperature TI _i ^* , and the planned post-stage cooling time tcf _i ^* , the planned cooling in the period until each segment of the steel sheet 1 reaches the cooling end position from the intermediate position M Intensity (scheduled cold speed) Vcf _i ^* (i: segment number) is calculated (step S107). As described above, the amount of cooling water in each of the cooling zones 1Z to 19Z is controlled so that the cooling strength is constant during the cooling plate, so that the planned cooling strength Vcf _i ^* from the intermediate position M to the cooling end position is almost equal. It can be treated as a linear change, and the following formula (4)
Vcf _i ^* = (TI _i ^* −TE ^* ) / tcf _i ^* (4)
Can be calculated as

  Returning to FIG. 4, in step S <b> 200, actual intermediate temperature information at a predetermined portion in the longitudinal direction of the steel sheet 1 at the intermediate position M of the cooling device 4 is acquired. Hereinafter, with reference to FIG. 8, the process of acquiring the actual intermediate temperature information in step S200 will be described.

First, the surface temperature of the steel plate 1 measured by the intermediate position thermometer 7 is read at regular intervals (each segment), and the plate thickness direction average temperature TI _i ^R is calculated (step S201). The method for obtaining the temperature distribution in the thickness direction from the surface temperature is as described above.

Then, the sheet passing state of the steel plate 1 is monitored by the tracking function, and in other words, every time the specified distance advances, in other words, for the plurality of segments of the steel plate 1, the plate thickness direction average temperature TI _i ^R calculated in step S201. The average value TI ^{R for the} specified distance (hereinafter referred to as “actual intermediate temperature TI ^R ”) is expressed by the following equation (5)
TI ^R = Ave (TI _i ^R : i = the number of samplings for the specified distance) (5)
To calculate the actual intermediate temperature information (step S202). In addition, what is necessary is just to determine the length which has a significant effect in correction control of a boarding speed from the past performance etc. how many segments a designated distance is made into.

Returning to FIG. 4, in step S300, the plate speed reflected in the cooling device 4 is corrected based on the planned cooling history acquired in step S100 and the actual intermediate temperature TI ^R acquired in step S200. (Step S300). Hereinafter, with reference to FIG. 9, the correction process of the sheet feeding speed in step S300 will be described.

First, each time the steel sheet 1 advances by a specified distance, the planned cooling intensity average Vcf ^* until the specified length reaches the cooling end position from the intermediate position M is calculated as the planned cooling intensity Vcf _i ^* calculated in step S107 ^. Using the following formula (6)
Vcf ^* = Ave (Vcf _i ^* : i = the number of samplings for the specified distance) (6)
(Step S301).

Next, based on the target cooling end temperature TE ^* , the actual intermediate temperature TI ^R calculated in step S202, and the planned cooling intensity average Vcf ^* calculated in step S301, the specified length of the steel sheet 1 is set at the intermediate position M. The cooling time tcf ^R (hereinafter referred to as “necessary post-stage cooling time tcf ^R ”) from the time until the cooling end position is reached to the following expression (7)
tcf ^R = (TI ^R −TE ^* ) / Vcf ^* (7)
(Step S302). That is, the necessary post-stage cooling time tcf ^R until the plate thickness direction average temperature for the specified length of the steel plate 1 reaches the target cooling end temperature TE ^* is calculated.

Next, the cooling time tcb _i ^R until each segment of the steel plate 1 reaches the intermediate position M is obtained by tracking measurement, and the actual pre-stage cooling time average tcb ^R for the specified length of the steel plate 1 is expressed by the following equation (8).
tcb ^R = Ave (Tcb _i ^R : i = sampling number for the specified distance) (8)
(Step S303).

Next, using the required post-stage cooling time tcf ^R calculated in step S302 and the actual pre-stage cooling time average tcb ^R calculated in step S303, the necessary total cooling time te _i ′ for the specified length of the steel sheet 1 is obtained. (9)
te _i '= tcb ^R + tcf ^R (9)
(Step S304).

Next, using the correction gain Gv _I , the correction total cooling time te _i ′ s is expressed by the following equation (10)
te _i ′ s = te _i ^* − (te _i ^* −te _i ′) · Gv _I (10)
(Step S305). Here, the correction gain Gv _I adjusts the response and convergence of the control, and is normally set to a value of 0.8 to 1.0, but is appropriately adjusted according to the magnitude and fluctuation of the actual temperature error. do it.

Next, the rear stage cooling time correction rate KvI _j is calculated from the following equation (11) with the ratio between the required rear stage cooling time and the planned rear stage cooling time.
KvI _j = (te ^* −tcb ^* ) / (te _i ′ s−tcb ^R ) (11)
However, te ^* : the average of the planned total cooling time for the specified length, tcb ^* : the average of the pre-planned cooling time for the specified length, j: calculated by the control frequency index (step S306).

And the correction coefficient ΔVI _j of the sheet feeding speed is expressed by the following equation (12)
ΔVI _j = KvI _j / KvI _(j-1) (12)
And the correction setting output of the sheet feeding speed is performed (step S307). In this example, the correction coefficient ΔVI _j for the current sheet feeding speed is calculated. However, the correction coefficient for the initial set speed may be calculated.

Thereby, the plate passing speed can be corrected so as to satisfy the target cooling end temperature TE ^* when the specified length of the steel plate 1 reaches the cooling end position.

  Returning to FIG. 4, the processes in steps S200 and S300 are repeatedly executed a predetermined number of times J until the entire length of the steel plate 1 passes (step S400).

  As described above, the amount of cooling water is controlled so that the cooling strength becomes substantially constant during cooling passage, and the passage speed is controlled so that the cooling end temperature of the steel plate becomes the target cooling end temperature. As a result, highly accurate dynamic control with excellent responsiveness is possible, and the influence on material fabrication can be reduced.

In the above embodiment, as the various temperature information such as the cooling start temperature T0, the planned intermediate temperature TI _i ^* , the actual intermediate temperature TI ^R, etc., instead of the surface temperature of the steel plate 1, the plate thickness direction average temperature is used. The reason is as follows. That is, (1) the target cooling end temperature TE ^* is given by the plate thickness direction average temperature, and (2) the temperature change on the surface of the steel plate 1 is very severe, and a large error may occur and the successive corrections may diverge. (3) Although the intermediate position thermometer 7 is disposed in the draining zone between the cooling zones, the surface temperature is in a rapid recuperation state, and accurate information cannot be obtained only by the surface temperature. .

(Example)
As shown in FIG. 10, under the same cooling conditions, the results were compared between when the cooling control according to the present invention was applied and when it was not applied. The cooling conditions are as follows: the thickness of the steel plate after finish rolling is 20 [mm], the plate length is 37 [m], the cooling start temperature is T0 = 750 [° C.], the target cooling end temperature is TE ^* = 435 [° C.], The initial sheet passing speed is 59.4 [m / min], and the correction gain is Gv _I = 0.9.

  As shown in FIG. 10, when the present invention is not applied, the actual cooling end temperature varies greatly at each position in the plate length direction, and moves away from the target cooling end temperature 435 [° C.] as it approaches the rear end of the steel plate (higher). There was a tendency.

  On the other hand, when the present invention is applied, the actual cooling end temperature does not change so much at each position in the plate length direction, and is near the target cooling end temperature 435 [° C.] even near the rear end of the steel plate. Results were obtained.

  Specifically, the cooling control apparatus 100 according to the above-described embodiment is configured by a computer apparatus or a computer system including a CPU, a RAM, a ROM, and the like. Accordingly, the present invention includes a computer program itself installed in a computer in order to realize each function processing of the present invention.

  Moreover, the said embodiment is only what showed the specific example in implementing this invention, and the technical scope of this invention should not be limitedly interpreted by these. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

It is a figure which shows an example of the steel plate manufacturing line to which this invention is applied. It is a figure which shows the internal structural example of a cooling device. It is a figure which shows schematic structure of the control system containing the cooling control apparatus of this embodiment. It is a flowchart for demonstrating the cooling control process by the cooling control apparatus of this embodiment. It is a characteristic view which shows the relationship between the time from the start of cooling, and the temperature change of a steel plate. It is a flowchart for demonstrating the acquisition process of a scheduled cooling history. It is a figure for demonstrating the temperature distribution of a plate | board thickness direction. It is a flowchart for demonstrating the acquisition process of track record intermediate temperature information. It is a flowchart for demonstrating the correction process of a boarding speed. It is a characteristic view which shows the result in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel plate 2 Finishing rolling mill 3 Straightening machine 4 Cooling device 5 Finishing front surface thermometer 6 Finishing rear surface thermometer 7 Intermediate position thermometer 100 Cooling control device 101 Planned cooling history acquisition part 102 Actual intermediate temperature information acquisition part 103 Passing plate speed correction part

Claims (10)

A cooling control method for controlling a cooling device that cools with a cooling water amount so that the cooling strength is substantially constant during cooling through plate while conveying the steel plate after finish rolling,
The cooling control method characterized by controlling the sheet passing speed of the said steel plate based on the performance intermediate temperature information of the said steel plate in the intermediate position of the said cooling device. A plan cooling history acquisition procedure for calculating a sheet passing speed according to target cooling end temperature information and reflecting it in the cooling device, and acquiring a scheduled cooling history of the steel sheet by the cooling device;
Actual intermediate temperature information acquisition procedure for acquiring actual intermediate temperature information at a predetermined portion in the longitudinal direction of the steel sheet at an intermediate position of the cooling device;
Based on the planned cooling history acquired by the scheduled cooling history acquisition procedure and the actual intermediate temperature information acquired by the actual intermediate temperature information acquisition procedure, the plate speed that corrects the plate speed reflected in the cooling device The cooling control method according to claim 1, further comprising a correction procedure.   In the scheduled cooling history acquisition procedure, a procedure for calculating scheduled intermediate temperature information at the intermediate position at each part in the longitudinal direction of the steel sheet based on cooling start temperature information at each part in the longitudinal direction of the steel sheet; Based on the procedure for calculating the planned post-stage cooling time until each part in the longitudinal direction reaches the cooling end position from the intermediate position, the target cooling end temperature information, the planned intermediate temperature information, and the planned post-stage cooling time, The cooling control method according to claim 2, further comprising: a procedure for obtaining a planned cooling strength in a period until each portion in the longitudinal direction of the steel plate reaches the cooling end position from the intermediate position.   In the sheet feeding speed correction procedure, the temperature of a predetermined part of the steel sheet based on the planned cooling strength obtained by the planned cooling history acquisition procedure and the actual intermediate temperature information acquired by the actual intermediate temperature information acquisition procedure. The cooling control method according to claim 3, further comprising: calculating a necessary post-stage cooling time for satisfying the target cooling end temperature information, and correcting the plate passing speed based on the necessary post-stage cooling time.   The cooling control method according to any one of claims 2 to 4, wherein the target cooling end temperature information is given by a plate thickness direction average temperature of the steel plate.   In the actual intermediate temperature information acquisition procedure, a plate thickness direction average temperature is calculated from a surface temperature of the steel plate measured by a thermometer arranged at an intermediate position of the cooling device, and each plate thickness direction at the predetermined portion The cooling control method according to any one of claims 2 to 5, wherein an average value of average temperatures is obtained as the actual intermediate temperature information. A cooling control device that controls a cooling device that cools with a cooling water amount such that the cooling strength is substantially constant during cooling through plate while conveying the steel plate after finish rolling,
A cooling control apparatus comprising means for controlling a sheet passing speed of the steel sheet based on the actual intermediate temperature information of the steel sheet at an intermediate position of the cooling apparatus. A scheduled cooling history acquisition means for calculating a sheet passing speed according to target cooling end temperature information and reflecting the calculated speed on the cooling device, and acquiring a scheduled cooling history of the steel sheet by the cooling device;
Actual intermediate temperature information acquisition means for acquiring actual intermediate temperature information at a predetermined portion in the longitudinal direction of the steel sheet at an intermediate position of the cooling device;
Based on the planned cooling history acquired by the planned cooling history acquisition means and the actual intermediate temperature information acquired by the actual intermediate temperature information acquisition means, the plate speed that corrects the plate speed reflected in the cooling device The cooling control device according to claim 7, further comprising a correction unit. A computer program for controlling a cooling device that cools with a cooling water amount such that the cooling strength in the cooling plate is substantially constant while conveying the steel plate after finish rolling,
A computer program that causes a computer to execute a process of controlling a sheet passing speed of the steel sheet based on actual intermediate temperature information of the steel sheet at an intermediate position of the cooling device. Actual intermediate temperature information acquisition processing for acquiring actual intermediate temperature information at a predetermined portion in the longitudinal direction of the steel sheet at an intermediate position of the cooling device;
Based on the planned cooling history acquired by the scheduled cooling history acquisition process and the actual intermediate temperature information acquired by the actual intermediate temperature information acquisition process, the plate speed that corrects the plate speed reflected in the cooling device The computer program according to claim 9, wherein the computer executes the correction process.

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