JP2021154367A - Controlled cooling method and controlled cooling device of steel plate - Google Patents

Abstract

To provide a controlled cooling method and a controlled cooling device of a steel plate capable of cooling a temperature of the steel plate to a target temperature accurately without requiring much labor even when a set flow rate of cooling water used in a temperature estimation model and an actual flow rate do not correspond to each other.SOLUTION: A controlled cooling method of a steel plate includes a measurement step of measuring a temperature of the steel plate on the inlet side and the outlet side of a cooling device at every cut sheet as a virtual control unit of the steel plate produced continuously in a longitudinal direction of the steel plate, an estimation step of estimating the temperature of the steel plate on the outlet side of the cooling device at every cut sheet according to a temperature estimation model by using the measured temperature of the cut sheet on the inlet side of the cooling device and a flow rate set value of cooling water when the cut sheet passes through the cooling device, and a correction step of correcting the flow rate set value of cooling water in a temperature estimation model so that the measured temperature of the steel plate on the outlet side of the cooling device and the estimated temperature of the steel plate on the outlet side of the cooling device in the estimation step correspond to each other over all cut sheets.SELECTED DRAWING: Figure 2

Description

The present invention relates to a controlled cooling method and a controlled cooling device for a steel sheet.

In the cooling temperature control of steel sheets represented by hot-rolled steel sheets and thick steel sheets, the temperature change of the steel sheet due to water cooling is predicted using a temperature prediction model before the start of cooling, and the temperature of the steel sheet is targeted at the completion of cooling based on the prediction result. Cooling is performed after calculating the usage pattern of the cooling water valve, the amount of cooling water, and the steel plate transport speed so that the temperature is reached. Therefore, the accuracy of predicting the temperature change of the steel sheet due to water cooling affects the accuracy of the temperature control of the steel sheet. If the temperature of the steel sheet at the completion of cooling is far from the target temperature, the material properties required for the product cannot be obtained. Therefore, it is required to control the temperature of the steel sheet at the completion of cooling with high accuracy. Further, in recent years, the length of the steel sheet tends to be long in order to improve the production efficiency, and it is required to control the temperature at the completion of cooling with high accuracy in the longitudinal direction of the steel sheet. Against this background, in general steel sheet cooling temperature control, feedback control is applied in which the cooling device is operated so as to suppress the control deviation, which is the deviation between the actual temperature of the steel sheet and the predicted temperature during cooling. .. However, in reality, there is a time delay until the temperature of the steel sheet is measured after the cooling water is applied, a time delay due to the calculation time of the feedback control, a response delay of the cooling water valve, etc. It cannot be carried out. Further, in general, since the delay time is set in the feedback control so that the fluctuation of the control amount does not become steep, if the control deviation is large, it takes a long time to sufficiently suppress the control deviation.

Therefore, by modifying the parameters of the temperature prediction model based on the deviation between the actual temperature of the steel plate and the predicted temperature and reflecting it in the subsequent temperature prediction calculation, it is possible to suppress the temperature prediction deviation in the section to which feedback control is not applied. It is done. In particular, the temperature change of the steel sheet due to water cooling is predicted using the actual data such as the temperature of the steel sheet measured before the start of cooling, the actual amount of cooling water, and the actual transfer speed of the steel sheet, and the deviation from the actual temperature of the steel sheet measured after the completion of cooling is calculated. Several techniques have been proposed to modify the parameters of the temperature prediction model to suppress them. Specifically, in Patent Document 1, the correction parameter of the heat transfer coefficient in the temperature prediction model is expressed by a nonlinear equation according to the rolling state, and the parameter of the nonlinear equation is suppressed so as to suppress the deviation between the actual temperature of the steel plate and the predicted temperature. The technique to correct is described. Further, in Patent Document 2, the correction coefficient of the total heat flux is calculated so as to suppress the temperature prediction deviation with respect to the actual temperature of the steel plate, and the operation conditions and the correction coefficient are linked and stored in the database. The technology that searches the operating conditions in the database and reflects the correction coefficient searched in the database when calculating the temperature prediction is described. Further, in Patent Document 3, the transformation calorific value of the steel sheet is calculated so as to suppress the temperature prediction deviation, and the transformation rate of the steel sheet is calculated and calculated by comparing with the transformation calorific value when the steel sheet is 100% transformed. A technique for modifying the parameters of the transformation rate equation using the transformed transformation rate is described.

JP-A-2007-44715 Japanese Unexamined Patent Publication No. 2011-200914 Japanese Unexamined Patent Publication No. 2013-766

However, in the technique described in Patent Document 1-3, the parameters of the temperature prediction model are modified so as to suppress the temperature prediction deviation, but the set flow rate of the cooling water used in the temperature prediction model and the actual flow rate match. It does not disclose or suggest measures to be taken if it does not. The set flow rate and actual flow rate of the cooling water used in the temperature prediction model are as follows: the flow rate decreases due to impurities contained in the cooling water sticking to the inner wall of the pipe and the cooling water valve, the flow rate decreases due to aging of the water supply pump, and the cooling water valve. It does not always match due to factors such as changes in flow rate due to deformation. If the cooling water flow rate of each cooling water valve changes uniformly, the deviation of the cooling water flow rate can be suppressed by the technique described in Patent Document 1-3, but the change in the actual flow rate due to the above-mentioned factors is the cooling water. Not uniform between valves. Further, although the discrepancy between the set flow rate of the cooling water and the actual flow rate can be suppressed by the feedback control described above, the feedback control cannot be executed over the entire length of the steel sheet for the reason described above. Therefore, it is common practice to adjust the set flow rate and the actual flow rate of the cooling water in the temperature prediction model so that the set flow rate of the cooling water and the actual flow rate match with each other using a flow meter before the start of cooling. Adjustment work cannot be performed frequently in terms of human cost and time cost. Therefore, even if the set flow rate of the cooling water used in the temperature prediction model and the actual flow rate do not match, the technology that can accurately cool the temperature of the steel sheet to the target temperature without much labor is required. It was expected to be provided.

The present invention has been made in view of the above problems, and an object of the present invention is to put a lot of effort even when the set flow rate of the cooling water used in the temperature prediction model and the actual flow rate do not match. It is an object of the present invention to provide a controlled cooling method and a controlled cooling device for a steel sheet capable of accurately cooling the temperature of the steel sheet to a target temperature without needing to do so.

In the controlled cooling method of the steel plate according to the present invention, the temperature of the steel plate on the outlet side of the cooling device is predicted by using the temperature prediction model, and the temperature of the steel plate on the outlet side of the cooling device is targeted based on the predicted temperature of the steel plate. It is a control cooling method of a steel plate that controls the flow rate of cooling water injected from a cooling device so as to reach a temperature, and continuously generates the temperature of the steel plate on the inlet side and the exit side of the cooling device in the longitudinal direction of the steel plate. The measurement step measured for each cut plate, which is the control unit of the virtual steel plate, the temperature of the cut plate on the entrance side of the cooling device measured in the measurement step, and the cooling when the cut plate passes through the cooling device. A prediction step of predicting the temperature of the steel plate on the outlet side of the cooling device for each cutting plate by the temperature prediction model using the water flow rate set value, and a steel plate on the outlet side of the cooling device measured in the measurement step. The correction step of correcting the flow rate set value of the cooling water in the temperature prediction model so that the temperature of the above and the temperature of the steel plate on the outlet side of the cooling device predicted in the prediction step match over all the cutting plates. It is characterized by including.

In the control cooling method of the steel plate according to the present invention, in the above invention, the correction step is the temperature of the steel plate on the exit side of the cooling device measured in the measurement step and the output of the cooling device predicted in the prediction step. It is characterized by including a step of calculating the deviation from the temperature of the steel plate on the side for each cut plate and correcting the flow rate set value of the cooling water in the temperature prediction model based on the correlation between the deviation and the flow rate set value.

In the control cooling method of the steel plate according to the present invention, in the above invention, the correction step is the temperature of the steel plate on the exit side of the cooling device measured in the measurement step and the output of the cooling device predicted in the prediction step. The deviation from the temperature of the steel plate on the side is calculated for each cut plate, the total value of the deviations of all the cut plates is calculated as the total deviation, and the flow rate setting value of the cooling water in the temperature prediction model is calculated based on the calculated total deviation. It is characterized by including a step of correction.

In the control cooling method of the steel plate according to the present invention, in the above invention, the correction step is the temperature of the steel plate on the exit side of the cooling device measured in the measurement step and the output of the cooling device predicted in the prediction step. The deviation from the temperature of the steel plate on the side is calculated for each cut plate, the total value of the deviations of all the cut plates is calculated as the total deviation, and the calculated total deviation and the total deviation calculated for the most recently cooled steel plate It is characterized by including a step of calculating the sum of the above and correcting the flow rate set value of the cooling water in the temperature prediction model based on the calculated sum.

The steel plate control cooling device according to the present invention predicts the temperature of the steel plate on the exit side of the cooling device using a temperature prediction model, and targets the temperature of the steel plate on the exit side of the cooling device based on the predicted temperature of the steel plate. A steel plate control cooling device that controls the flow rate of cooling water injected from the cooling device so as to reach a temperature, and continuously generates the temperature of the steel plate on the inlet side and the exit side of the cooling device in the longitudinal direction of the steel plate. The measuring means that measures each cut plate, which is the control unit of the virtual steel plate, the temperature of the cut plate on the entrance side of the cooling device measured by the measuring means, and the cooling when the cut plate passes through the cooling device. Using the water flow rate set value, the temperature of the steel plate on the outlet side of the cooling device is predicted for each cut plate by the temperature prediction model, and the temperature of the steel plate on the outlet side of the cooling device measured by the measuring means is used. It is characterized by comprising a control means for correcting the flow rate set value of the cooling water in the temperature prediction model so that the predicted temperature of the steel plate on the outlet side of the cooling device matches over all the cut plates. ..

According to the controlled cooling method and the controlled cooling device for the steel sheet according to the present invention, even if the set flow rate of the cooling water used in the temperature prediction model and the actual flow rate do not match, a lot of labor is not required. The temperature of the steel sheet can be accurately cooled to the target temperature.

FIG. 1 is a schematic view showing a configuration of a cooling line for a hot-rolled steel sheet to which a controlled cooling method for a steel sheet according to an embodiment of the present invention is applied. FIG. 2 is a flowchart showing the flow of the controlled cooling process according to the embodiment of the present invention. FIG. 3 is a diagram showing the actual temperature, the conventional example, and the invention examples 1 to 4 in the section from the calculation start to the cutting plate number 500. FIG. 4 is a diagram showing the actual temperature, the conventional example, and the invention examples 1 to 4 in a section from the cutting plate number 3000 to the cutting plate number 3500. FIG. 5 is a diagram showing the actual temperature, the conventional example, and the invention examples 1 to 4 in a section from the cutting plate number 4500 to the cutting plate number 5000.

Hereinafter, a controlled cooling method for a steel sheet according to an embodiment of the present invention will be described with reference to the drawings.

[Composition of cooling line for hot-rolled steel sheet]
First, with reference to FIG. 1, the configuration of a cooling line for a hot-rolled steel sheet to which the controlled cooling method for a steel sheet according to the embodiment of the present invention is applied will be described.

FIG. 1 is a schematic view showing a configuration of a cooling line for a hot-rolled steel sheet to which a controlled cooling method for a steel sheet according to an embodiment of the present invention is applied. As shown in FIG. 1, the cooling line 1 (hereinafter, abbreviated as cooling line 1) of the hot-rolled steel sheet to which the controlled cooling method of the steel sheet according to the embodiment of the present invention is applied is transported in the transport direction indicated by the arrow. It is a line that cools the temperature of the steel sheet to the target temperature by injecting cooling water onto the steel sheet, and includes cooling water valves 2a to 2o, thermometers 3a and 3b, a computer 4, and a control panel 5.

The cooling water valves 2a to 2o are arranged to face each other on the front surface and the back surface of the steel sheet, and cool the steel sheet by injecting cooling water toward the front surface and the back surface of the steel sheet according to a control signal from the control panel 5.

The thermometers 3a and 3b are arranged on the inlet side and the outlet side of the cooling line 1, respectively, and measure the temperature of the steel plate on the inlet side and the outlet side of the cooling line 1 in a cycle equal to or less than the control cycle of the cooling water valves 2a to 2o, respectively. .. The thermometers 3a and 3b each output an electric signal indicating the measured temperature of the steel plate to the computer 4.

The computer 4 is composed of an information processing device such as a computer. The computer 4 cools the temperature of the steel sheet to the target temperature by executing the control cooling process described later. Specifically, the computer 4 is injected from the cooling water valves 2a to 2o via the control panel 5 based on the temperature of the steel plate on the inlet side and the outlet side of the cooling line 1 measured by the thermometers 3a and 3b. The temperature of the steel plate is cooled to the target temperature by controlling the flow rate of the cooling water.

In the cooling line 1 of the hot-rolled steel sheet having such a configuration, the set flow rate of the cooling water used in the temperature prediction model and the actual flow rate do not match because the computer 4 executes the control cooling process shown below. Even in this case, the temperature of the steel sheet is accurately cooled to the target temperature without requiring a lot of labor. Hereinafter, the operation of the computer 4 when executing the controlled cooling process according to the embodiment of the present invention will be described with reference to FIG.

In the present specification, the temperature prediction model means a mathematical model that describes heat exchange between cooling water, air, rolls, etc. and a steel plate. The input variables of the temperature prediction model include the initial temperature of the steel plate and the flow rate (flow rate set value) of the cooling water injected from the cooling water valves 2a to 2o, and the output variable of the temperature prediction model is the output of the cooling line 1. The temperature of the steel plate on the side.

[Control cooling process]
FIG. 2 is a flowchart showing the flow of the controlled cooling process according to the embodiment of the present invention. The flowchart shown in FIG. 2 starts at the timing when the cut plate of the steel plate (the control unit of the virtual steel plate continuously generated in the longitudinal direction of the steel plate) passes through the thermometer 3a, and the control cooling process is the process of step S1. Proceed to.

In the process of step S1, the computer 4 measures the temperature of each cutting plate i on the inlet side and the outlet side of the cooling line 1 by using the thermometers 3a and 3b and a well-known tracking technique. Note that i indicates unique identification information assigned to each cutting plate. As a result, the process of step S1 is completed, and the control cooling process proceeds to the process of step S2.

In the process of step S2, the computer 4 obtains the flow setpoint Q _i ^k of each cooling water valve k at which each Setsuban i passes through the cooling water valve 2A～2o. Note that k indicates unique identification information assigned to each cooling water valve. As a result, the process of step S2 is completed, and the control cooling process proceeds to the process of step S3.

In the process of step S3, the computer 4 uses the temperature prediction model to obtain the temperature of each cutting plate i on the entry side of the cooling line 1 acquired in the processing of step S1 and each cutting plate i acquired in the processing of step S2. There predicts the temperature of each switching plate i in the outlet side of the cooling line 1 and a flow setpoint Q _i ^k of the cooling water valve k at the time of passing. In this process, assuming that the heat flux due to the cooling water is represented by a function of the set flow rate f (V) of the cooling water, the flow rate correction coefficient W _k that corrects the flow rate of the cooling water injected from the cooling water valve k is set. The temperature of each cutting plate i is predicted by using the heat flux due to the cooling water as f (V, W _k). In the first controlled cooling process, the flow rate correction coefficient W _k is set to the initial value. As a result, the process of step S3 is completed, and the control cooling process proceeds to the process of step S4.

In the process of step S4, the steel plate is cooled in order for the computer 4 to reflect the fluctuation of the flow rate of the cooling water injected from each cooling water valve k in the temperature prediction calculation of each cutting plate i on the exit side of the cooling line 1. After passing through 1, the flow rate correction coefficient W _k of each cooling water valve k is corrected. Specifically, first, the computer 4 first determines the temperature of each cutting plate i on the exit side of the cooling line 1 measured in the process of step S1 and each cut on the exit side of the cooling line 1 calculated in the process of step S3. _{The deviation ΔT i} from the temperature of the plate i is calculated for each cutting plate i. Then, the computer 4 calculates the correlation between the calculated deviation [Delta] T _i and the flow rate set value Q _i ^k of the cooling water valve k. Specifically, the computer 4 linearly regresses the deviation ΔT _{i with the flow rate set value Q i} ^k by the least squares method for the cooling water valve k, and constructs the mathematical formula (1) shown below. The computer 4, when the inclination _{A k} of the formula (1) is equal to or greater than the predetermined value x, correcting the flow rate correction coefficient _{W k} in the flow rate correction coefficient _{W k '(= W k -α} ), formula (1) When the inclination _{Ak of} is less than the predetermined value x, the flow rate correction coefficient W _k is corrected to the flow rate correction coefficient W _k '(= W _k + α). However, α indicates a predetermined constant. Note that the cooling water valve k which flow setpoint Q _i ^k is not changed, the processing of step S4 shall not be executed. As a result, the process of step S4 is completed, and the control cooling process proceeds to the process of step S5.

In the process of step S5, the computer 4 cools the hot-rolled steel plate so that the short-term fluctuation of the total flow rate of the cooling water is reflected in the temperature prediction calculation of each cutting plate i on the exit side of the cooling line 1. _{The flow rate correction coefficient Wk} is uniformly corrected for all cooling water valves that inject water. Specifically, first, the computer 4 calculates the total value of the deviation ΔT _i of all the cutting plates as the _{total deviation ΣΔT i by using the deviation ΔT i calculated in the process of step S4. Next, when the total deviation ΣΔT i} is equal to or greater than a predetermined value y for the cooling water valve in which the computer 4 injects cooling water while cooling the hot-rolled steel plate _{, the flow rate correction coefficient W k is set} to the flow rate correction coefficient W _k '(. = W _k × (1 + β)), and if the total deviation ΣΔT _i is less than the predetermined value y, the flow rate correction coefficient W _{k is changed} to the flow rate correction coefficient W _k ′ (= W _k × (1-β)). Correct to. However, β indicates a predetermined constant. As a result, the process of step S5 is completed, and the control cooling process proceeds to the process of step S6.

In the process of step S6, the computer 4 _{determines whether or not the correction process of the flow rate correction coefficient W k} in the processes of steps S4 and S5 has the same tendency as the correction process _{of the flow rate correction coefficient W k} in the other hot-rolled steel plate. _{The determination is made, and the flow rate correction coefficient Wk} is corrected so as to suppress or promote the correction processing in steps S4 and S5 based on the determination result. Specifically, first, the computer 4 calculates the total deviation ShigumashigumaderutaT _i combined with ShigumaderutaT _i for a plurality of hot-rolled steel sheet total deviation ShigumaderutaT _i calculated cooled in recent in the process of step S5. _{Next, the computer 4 sets the flow rate correction coefficient W k} to the flow rate correction coefficient W _k ′ _{when the total deviation ΣΣΔT i} is equal to or greater than the predetermined value z for the cooling water valves in which the cooling water is injected onto the plurality of hot-rolled steel plates. Corrected to (= W _k × (1 + γ)), and when the total deviation ΣΣΔT _i is equal to or greater than the predetermined value z, the flow rate correction coefficient W _{k is changed} to the flow rate correction coefficient W _k '(= W _k × (1-γ)). to correct. However, γ indicates a predetermined constant. As a result, the process of step S6 is completed, and the control cooling process proceeds to the process of step S7.

〔Example〕
In this example, a temperature prediction simulation of a hot-rolled steel sheet was performed. Specifically, in this simulation, for the cooling results of 5000 cut plates of a predetermined length (cut plate numbers 1 to 5000 in order from the tip) generated continuously from the tips of the 92 connected coils. , Conventional temperature prediction calculation (conventional example), temperature prediction calculation in which the processes of steps S4, S5, and S6 shown in FIG. 2 are performed independently (Invention Examples 1 to 3), and the processes of steps S4 to S6 shown in FIG. The temperature prediction calculation (Invention Example 4) in which all of the above were carried out was performed. The constants in each calculation of steps S4 to S6 were x = 10 ° C., α = 0.050, y = 10 ° C., β = 0.02, z = 10 ° C., and γ = 0.0. The initial values of the flow rate correction coefficients were all set to 1.

FIG. 3 shows the actual temperature (line L1), the conventional example (line L2), the invention example 1 (line L3), the invention example 2 (line L4), the invention example 3 (line L5), and the invention example 4 (line L6). Is illustrated in the section from the start of calculation to the cutting plate number 500. As shown in FIG. 3, since the initial value of the flow rate correction coefficient is 1, the conventional example and the invention examples 1 to 4 initially match. Further, in the section up to the cutting plate number 200, since the actual temperature and the magnitude of Invention Examples 1 to 4 appear alternately, the correction direction of the flow rate correction coefficient also alternates, and the conventional example and Invention Examples 1 to 4 are not so different. No.

However, in the section of the cutting plate number 200 to 480, the hot-rolled steel plate whose actual temperature is about 20 ° C. higher than that of Invention Examples 1 to 4 continues, so that the predicted temperature is increased in the process of step S5. It can be seen from Invention Example 2 (line L4) in this section that the flow rate correction coefficient is continuously corrected in the negative direction. On the other hand, since there is not much tendency for the temperature prediction error due to the difference in the set flow rate of each cooling water valve, the correction by the process of step S4 is not performed so much (Invention Example 1 (line L3)). Further, in the vicinity of the cut plate number 430, since the deviation of the same code continues over the latest plurality of hot-rolled steel sheets, the correction by the process of step S6 is performed (Invention Example 3 (L5)).

FIG. 4 shows the actual temperature (line L1), the conventional example (line L2), the invention example 1 (line L3), the invention example 2 (line L4), the invention example 3 (line L5), and the invention example 4 (line L6). Is illustrated in the section from the cutting plate number 3000 to the cutting plate number 3500. As shown in FIG. 4, the correction by each process of steps S4 to S6 is progressing, and it can be seen that Invention Examples 1 to 3 are more accurate than the conventional examples. Further, FIG. 5 shows the actual temperature (line L1), the conventional example (line L2), the invention example 1 (line L3), the invention example 2 (line L4), the invention example 3 (line L5), and the invention example 4 (line L5). L6) is shown in the section from the cutting plate number 4500 to the cutting plate number 5000. The correction by the processing of steps S5 and S6 works effectively, and while Invention Examples 2 and 3 follow the actual temperature, the change in the flow rate of the valve is small and the correction by the processing of step S4 is not performed. Example 1 cannot follow the change in the actual temperature. The above results are summarized in Table 1 below, and it can be seen that Invention Examples 1 to 3 also have improved accuracy as compared with the conventional examples, but Invention Example 4 has the highest accuracy. From the above results, the effect of improving the temperature prediction accuracy by implementing the present invention was confirmed.

Although the embodiment to which the invention made by the present inventors has been applied has been described above, the present invention is not limited by the description and the drawings which form a part of the disclosure of the present invention according to the present embodiment. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

1 Cooling line of hot-rolled steel sheet 2a to 2o Cooling water valve 3a, 3b Thermometer 4 Computer 5 Control panel

Claims (5)

The temperature of the steel plate on the outlet side of the cooling device is predicted using the temperature prediction model, and the temperature of the steel plate on the outlet side of the cooling device is injected from the cooling device so as to reach the target temperature based on the predicted temperature of the steel plate. A controlled cooling method for steel sheets that controls the flow rate of cooling water.
A measurement step of measuring the temperature of the steel plate on the entrance side and the exit side of the cooling device for each cut plate, which is a control unit of a virtual steel plate continuously generated in the longitudinal direction of the steel plate.
Using the temperature of the cutting plate on the entrance side of the cooling device measured in the measurement step and the flow rate setting value of the cooling water when the cutting plate passes through the cooling device, the exit side of the cooling device according to the temperature prediction model. Prediction step for predicting the temperature of the steel plate for each cutting plate in
The temperature is predicted so that the temperature of the steel plate on the outlet side of the cooling device measured in the measurement step and the temperature of the steel plate on the outlet side of the cooling device predicted in the prediction step coincide with each other over the entire cutting plate. A correction step that corrects the cooling water flow setting value in the model, and
A controlled cooling method for a steel sheet, which comprises. In the correction step, the deviation between the temperature of the steel plate on the outlet side of the cooling device measured in the measurement step and the temperature of the steel plate on the outlet side of the cooling device predicted in the prediction step is calculated for each cut plate. The controlled cooling method for a steel sheet according to claim 1, further comprising a step of correcting the flow rate set value of the cooling water in the temperature prediction model based on the correlation between the deviation and the flow rate set value. In the correction step, the deviation between the temperature of the steel plate on the outlet side of the cooling device measured in the measurement step and the temperature of the steel plate on the outlet side of the cooling device predicted in the prediction step is calculated for each cut plate. 1 or 2, wherein the total value of the deviations of all the cutting plates is calculated as the total deviation, and the step of correcting the flow rate set value of the cooling water in the temperature prediction model based on the calculated total deviation is included. A controlled cooling method for a steel plate according to. In the correction step, the deviation between the temperature of the steel plate on the outlet side of the cooling device measured in the measurement step and the temperature of the steel plate on the outlet side of the cooling device predicted in the prediction step is calculated for each cut plate. , The total value of the deviations of all the cutting plates is calculated as the total deviation, the sum of the calculated total deviation and the total deviation calculated for the most recently cooled steel plate is calculated, and the temperature is predicted based on the calculated sum. The controlled cooling method for a steel plate according to any one of claims 1 to 3, further comprising a step of correcting a cooling water flow rate set value in the model. The temperature of the steel plate on the outlet side of the cooling device is predicted using the temperature prediction model, and the temperature of the steel plate on the outlet side of the cooling device is injected from the cooling device so as to reach the target temperature based on the predicted temperature of the steel plate. A steel plate control cooling device that controls the flow rate of cooling water.
A measuring means for measuring the temperature of the steel plate on the entrance side and the exit side of the cooling device for each cut plate,
Using the temperature of the cutting plate on the entrance side of the cooling device measured by the measuring means and the flow rate setting value of the cooling water when the cutting plate passes through the cooling device, the exit side of the cooling device according to the temperature prediction model. The temperature of the steel plate in the above is predicted for each cut plate, which is a virtual steel plate control unit continuously generated in the longitudinal direction of the steel plate, and is predicted as the temperature of the steel plate on the outlet side of the cooling device measured by the measuring means. A control means for correcting the flow rate set value of the cooling water in the temperature prediction model so that the temperature of the steel plate on the outlet side of the cooling device matches the entire cut plate.
A controlled cooling device for a steel plate, which comprises.

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