JP7251533B2 - Method for calculating water cooling heat transfer coefficient of steel plate, method for cooling steel plate, and method for manufacturing steel plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for calculating a water cooling heat transfer coefficient of a steel plate, a method for cooling a steel plate, and a method for manufacturing a steel plate.

In a cooling device that cools a steel plate hot-rolled by a rolling mill, generally, when determining the conveying speed of the steel plate, a cooling calculation using heat flux is performed to reach the target cooling stop temperature. method is done.

In addition, conventionally, when calculating the heat flux, a table partitioned by steel type, plate thickness, cooling start temperature and cooling stop temperature is used, and the heat flux calculation formula A method of securing cooling accuracy by multiplying the water-cooling heat transfer coefficient, which is an internal term of , by a gain (learning value) is used. However, the method using this table value has limitations in improving the cooling accuracy.

Therefore, in order to solve such problems, for example, in Patent Documents 1 and 2, past data such as the composition of the steel sheet, the thickness, the water temperature, the steel sheet conveying speed, the cooling start temperature and the cooling stop temperature are used to determine the water cooling heat transfer coefficient A method of calculating the learning value (correction value) of is proposed.

JP 2014-108446 A JP 2012-101235 A

In the methods proposed in Patent Documents 1 and 2, the accuracy of calculating the learned value of the water-cooling heat transfer coefficient is higher than in the conventional method using table values. However, there is room for improvement from the viewpoint of further improving the cooling accuracy.

The present invention has been made in view of the above, and a method for calculating a water cooling heat transfer coefficient of a steel plate that can improve the cooling accuracy of the steel plate by increasing the calculation accuracy of the learned value of the water cooling heat transfer coefficient. An object of the present invention is to provide a steel plate cooling method and a steel plate manufacturing method.

In order to solve the above-described problems and achieve the object, a method for calculating a water-cooling heat transfer coefficient of a steel sheet according to the present invention provides a method for calculating the water-cooling heat transfer coefficient of a steel sheet when the steel sheet rolled by a rolling mill is cooled by a cooling device while being transported. A method for calculating a cold heat transfer coefficient, wherein a parameter including at least one physical quantity directly or indirectly related to the temperature distribution, the degree of temperature decrease, or the degree of reheating of the steel plate after cooling is used as an input variable, and the steel plate By inputting the parameters of the steel sheet to be rolled to a prediction model generated from past operation data of the cooling device including the past physical quantities, with the relevant value of the water cooling heat transfer coefficient as an output variable, The relevant value is predicted for the steel sheet to be rolled, and the water cooling heat transfer coefficient is determined from the predicted relevant value.

Further, in the method for calculating the water cooling heat transfer coefficient of a steel plate according to the present invention, in the above invention, the related value is a correction value for correcting the water cooling heat transfer coefficient, and the water cooling coefficient is calculated by the predicted correction value. Correct the heat transfer coefficient.

Further, in the method for calculating a water cooling heat transfer coefficient of a steel plate according to the present invention, in the above invention, the related value is a corrected water cooling heat transfer coefficient.

Further, a method for calculating a water cooling heat transfer coefficient of a steel plate according to the present invention is the above invention, wherein the cooling device is provided in a plurality of cooling zones provided along the conveying direction of the steel plate and in each cooling zone, nozzles for discharging cooling water to the upper and lower surfaces of the steel plate, respectively, and the physical quantity includes a cooling zone control pattern indicating a cooling zone used for cooling the steel plate among the plurality of cooling zones.

Further, a method for calculating a water cooling heat transfer coefficient of a steel plate according to the present invention is the above invention, wherein the cooling device is provided in a plurality of cooling zones provided along the conveying direction of the steel plate and in each cooling zone, Of the nozzles for discharging cooling water to the upper and lower surfaces of the steel plate and the nozzles for discharging cooling water to the lower surface of the steel plate, the nozzle provided on the most upstream side in the conveying direction of the steel plate is provided with cooling water by the nozzle. and a masking device that adjusts the amount of discharge of cooling water, wherein the physical quantity includes the amount of cooling water discharged by the most upstream nozzle adjusted by the masking device.

Further, the method for calculating the water-cooling heat transfer coefficient of a steel plate according to the present invention is, in the above-described invention, the steel plate before cooling is rolled down to the upstream side of the conveying direction of the steel plate in the cooling device to correct the distortion of the steel plate. The physical quantity includes a load applied to the leveler.

Further, in the method for calculating the water-cooling heat transfer coefficient of a steel sheet according to the present invention, in the above-described invention, the physical quantity includes the temperature of cooling water for cooling the steel sheet and the time at which the cooling water is discharged.

In order to solve the above-described problems and achieve the object, a steel plate cooling method according to the present invention calculates a heat flux using the water-cooling heat transfer coefficient calculated by the above-described method for calculating a water-cooling heat transfer coefficient of a steel plate. and determining the conveying speed of the steel sheet based on the heat flux.

In order to solve the above-described problems and achieve the object, a method for manufacturing a steel sheet according to the present invention includes a step of cooling a hot-rolled steel sheet using the steel sheet cooling method described above.

According to the method for calculating the water cooling heat transfer coefficient of a steel plate, the method for cooling a steel plate, and the method for manufacturing a steel plate according to the present invention, the temperature distribution, the degree of temperature decrease, or the degree of reheating of the steel plate after cooling, which were not considered in the past, In addition, by using a prediction model that has learned at least one directly or indirectly related physical quantity as an input variable, it is possible to improve the calculation accuracy of the learned value of the water cooling heat transfer coefficient, and improve the cooling accuracy of the steel plate. can be made

FIG. 1 is a diagram showing a schematic configuration of a steel plate manufacturing facility according to an embodiment of the present invention. FIG. 2 is a diagram showing a schematic configuration of a steel plate cooling apparatus according to an embodiment of the present invention. FIG. 3 is a diagram showing a schematic configuration of a water-cooling heat transfer coefficient calculation device according to an embodiment of the present invention. FIG. 4 is an embodiment of the present invention, and is a graph showing the result of comparing the accuracy of the learning values of the conventional method and the present invention using the back calculation learning values. FIG. 5 is an example of the present invention, and is a graph showing the result of comparing cold stop accuracy between the conventional method and the present invention.

A method for calculating a water cooling heat transfer coefficient of a steel plate, a method for cooling a steel plate, and a method for manufacturing a steel plate according to an embodiment of the present invention will be described with reference to the drawings.

[Manufacturing equipment for steel sheets]
First, the configuration of a steel plate manufacturing facility according to an embodiment of the present invention will be described with reference to FIG. The manufacturing facility 1 includes a heating furnace 10 , a rolling mill 20 , a leveler 30 , a cooling device 40 , a thermometer 50 and a conveying device 60 . As shown in the figure, the heating furnace 10, the rolling mill 20, the leveler 30, the cooling device 40, and the thermometer 50 are arranged in order from upstream to downstream in the direction in which the steel sheet S is conveyed.

The heating furnace 10 heats the steel sheet S being conveyed to a predetermined temperature. The rolling mill 20 performs rough hot rolling and finish rolling on the steel sheet S after heating. The leveler 30 rolls down the steel plate S before cooling to correct the distortion of the steel plate S. The cooling device 40 cools the steel sheet S after hot rolling and strain correction. The thermometer 50 measures the surface temperature of the steel sheet S after cooling and acquires the cooling stop temperature of the steel sheet S. The conveying device 60 conveys the steel plate S in a predetermined direction.

[Cooling device for steel plate]
Next, a specific configuration of the steel plate cooling device 40 according to the embodiment of the present invention will be described with reference to FIG.

The cooling device 40 is provided with a plurality of cooling zones along the direction in which the steel plate S is conveyed. The steel sheet S after hot rolling is cooled in each cooling zone in the cooling device 40 and carried out from the cooling device 40 . Each cooling zone of the cooling device 40 includes a draining roll 41 , a table roll 42 , an upper header 43 , an upper nozzle 44 , a lower header 45 , a lower nozzle 46 and a masking device 47 . Although only three cooling zones are shown in the figure, 14 cooling zones are actually provided, for example.

The drain roll 41 is a roll for cutting the cooling water discharged from the upper nozzle 44 so that it does not flow into the next cooling zone. The draining roll 41 is arranged directly above the table roll 42 . As a result, the steel sheet S is sandwiched between the draining roll 41 and the table roll 42 . In this way, the cooling zone is configured by the space where the draining rolls 41 and the table rolls 42 face each other.

The table roll 42 is a roll for transporting the steel plate S in the transport direction. The upper nozzle 44 is installed in the upper header 43 and discharges cooling water onto the upper surface of the steel plate S. As shown in FIG. The lower nozzle 46 is installed in the lower header 45 and discharges cooling water to the lower surface of the steel plate S. As shown in FIG. In addition, a plurality of lower nozzles 46 are arranged in the width direction and the length direction of the steel plate S. As shown in FIG.

The masking device 47 is for adjusting the amount of cooling water discharged by the lower nozzle 46 . The masking device 47 is provided in the lower nozzle 46 on the most upstream side in the conveying direction of the steel plate S among the lower nozzles 46 . In addition, the masking device 47 is operable perpendicularly to the conveying direction of the steel plate S. By changing the position of masking by the masking device 47, the opening degree of the outlet of the lower nozzle 46 changes, and the lower nozzle The amount of cooling water discharged by 46 changes.

In the steel plate cooling device 40 having the above configuration, the heat flux is calculated using the water-cooled heat transfer coefficient calculated by the method for calculating the water-cooled heat transfer coefficient of the steel plate described later, and based on the heat flux, the cooling A conveying speed determination step is performed to determine the conveying speed when the steel sheet S is cooled by the device 40 .

In the transport speed determination step, for example, the heat fluxes of the front and back surfaces of the steel plate water-cooled section are calculated by the following equation (1).

Also, the water-cooling heat transfer coefficient of the above formula (1) can be calculated, for example, by the following formula (2).

In the conveying speed determination step, the heat flux of the steel sheet S is calculated by the above equation (1) using the water cooling heat transfer coefficient calculated by the above equation (2) in the water cooling heat transfer coefficient calculation method described later. Then, the conveying speed of the steel sheet S is determined so that the actual cooling stop temperature of the steel sheet S matches the cooling stop temperature target.

[Configuration of Water Cooling Heat Transfer Coefficient Calculator]
Next, the configuration of the apparatus for calculating the water-cooling heat transfer coefficient of steel sheets according to the embodiment of the present invention will be described with reference to FIG. The computing device 100 includes an information processing device 101 , an input device 102 and an output device 103 .

The information processing device 101 is configured by a general-purpose device such as a personal computer or workstation, and includes a RAM 111, a ROM 112 and a CPU 113. FIG. The RAM 111 temporarily stores processing programs and processing data related to processing executed by the CPU 113 and functions as a working area for the CPU 113 .

The ROM 112 stores a control program 112a for calculating the water-cooling heat transfer coefficient of the steel plate according to the embodiment of the present invention, and a processing program and processing data for controlling the operation of the information processing apparatus 101 as a whole.

The CPU 113 controls the overall operation of the information processing apparatus 101 according to the control program 112 a and processing programs stored in the ROM 112 .

The input device 102 is composed of devices such as a keyboard, mouse pointer, numeric keypad, and the like, and is operated when inputting various information to the information processing device 101 . The output device 103 includes a display device, a printing device, and the like, and outputs various processing information of the information processing device 101 .

[Calculation method of water cooling heat transfer coefficient]
Next, a method of calculating the water-cooling heat transfer coefficient of the steel plate by the calculation device 100 will be described. In this method of calculating the water-cooling heat transfer coefficient, the water-cooling heat transfer coefficient of the steel sheet S when the steel sheet S rolled by the rolling mill 20 is cooled by the cooling device 40 while being conveyed is determined.

In the water-cooling heat transfer coefficient calculation method, a learning value prediction step and a water-cooling heat transfer coefficient calculation step are performed. In the learning value prediction step, by inputting the parameters of the steel sheet S to be rolled into the prediction model generated from the past operation data of the cooling device 40, the water cooling heat transfer coefficient of the steel sheet S to be rolled is calculated. Predict relevant values. This related value is, for example, the learning value (correction value) _K0 used when calculating the water-cooling heat transfer coefficient (see formula (2) above).

Here, the above prediction model uses, as an input variable, a parameter including at least one physical quantity directly or indirectly related to the temperature distribution, the degree of temperature decrease, or the degree of reheating of the steel sheet S after cooling. It is generated from the past operation data of the cooling device 40 including the past physical quantity, with the learning value _K0 for correcting the water cooling heat transfer coefficient as an output variable. Note that the prediction model is created in advance before executing the learning value prediction step and the water-cooling heat transfer coefficient calculation step.

Parameters input to the prediction model include, for example, the chemical composition of the steel sheet S (Si, C, Mn, Cr, Nb, N, Ti, Mo, V, Ni, B, Cu), thickness, width, length , slab weight, conveying speed, cooling start temperature target value, cooling stop temperature target value, finishing temperature actual value, heating furnace name, and the like.

Among the parameters input to the prediction model, physical quantities directly or indirectly related to the temperature distribution of the steel sheet S after cooling, the degree of temperature decrease, or the degree of reheating include, for example, the control pattern of the cooling zone, masking The amount of cooling water discharged by the lower nozzle 46 on the most upstream side adjusted by the device 47, the load of the leveler 30, the temperature of the cooling water for cooling the steel plate S, and the time of discharging the cooling water are listed. The reason for using each physical quantity will be described below.

(Control pattern of cooling zone)
Specifically, the control pattern of the cooling zone indicates the number indicating the cooling zone used for cooling the steel plate S among the plurality of cooling zones in the cooling device 40 . As shown in FIG. 2, the cooling device 40 is provided with a plurality of cooling zones along the conveying direction of the steel plate S. For example, there are cooling zones Nos. 1 to 14 in order from the upstream side. The conveying speed of the steel sheet S conveyed in each cooling zone can be adjusted (controlled), and the control pattern of the cooling zones, that is, which cooling zone is used for cooling, is determined based on the manufacturing instructions. It is determined.

A thermometer 50 (see FIG. 1) that acquires the cooling stop temperature of the steel plate S is installed, for example, 30 m downstream from the rear surface of the cooling device 40, and the steel plate S recovers heat during that 30 m distance. Then, when cooling, for example, when cooling zones 1 to 10 are used, when cooling zones 1 and 2 are used, when cooling zones 3 and 5 are used, and when cooling zones 6 and Since the cooling history of the steel plate S is different from the case of using the No. 10 cooling zone, the degree of heat recovery after the rear surface of the cooling device 40 is also different. Therefore, the cooling zone control pattern (differences in the cooling zones used during cooling) directly affects the degree of reheating of the steel sheet S after the completion of cooling, and greatly affects the cooling accuracy.

In this way, the degree of reheating after the completion of cooling is also considered by using the control pattern of the cooling zone, which directly affects the degree of reheating of the steel sheet S after the completion of cooling, as an input variable of the prediction model. A prediction model can be used, and the accuracy of calculation (prediction) of the learning value _K0 can be improved.

(Discharge amount of lower nozzle provided with masking device)
As shown in FIG. 2, below each cooling zone of the cooling device 40, for example, five rows of lower nozzles 46 are provided in the conveying direction of the steel plate S. A masking device 47 is provided to cover the outlet of the lower nozzle 46 . As the masking position of the masking device 47 changes, the opening of the outlet of the lower nozzle 46 changes, and the amount of cooling water discharged from the lower nozzle 46 changes.

Then, when the steel plate S starts to enter each cooling zone, the masking position is adjusted to adjust the temperature difference between the front and back surfaces of the steel plate S, thereby adjusting the strain of the steel plate S. The degree of opening of the outlet of the lower nozzle 46 by masking, that is, the amount of cooling water discharged from the lower nozzle 46 affects the distortion of the steel plate S. In addition, since the strain of the steel sheet S affects the temperature distribution and the degree of temperature decrease of the steel sheet S, the degree of influence on the cooling accuracy is large.

In this way, the amount of cooling water discharged from the lower nozzle 46 provided with the masking device 47, which indirectly affects the temperature distribution and the degree of temperature decrease of the steel sheet S after cooling is completed, can be used as an input variable of the prediction model. As a result, a prediction model that takes into consideration the temperature distribution and the degree of temperature decrease after the completion of cooling can be made, and the calculation (prediction) accuracy of the learning value _K0 can be improved.

(Load of leveler)
As shown in FIG. 1, a leveler 30 is provided upstream of the cooling device 40 (between the rolling mill 20 and the cooling device 40). This leveler 30 is for correcting the distortion of the steel sheet S by rolling down the steel sheet S before cooling. Therefore, the load applied to the leveler 30 affects the distortion of the steel plate S. In addition, since the strain of the steel sheet S affects the temperature distribution and the degree of temperature decrease of the steel sheet S, the degree of influence on the cooling accuracy is large.

In this way, by using the load of the leveler 30, which indirectly affects the temperature distribution and the degree of temperature drop of the steel sheet S after the completion of cooling, as an input variable of the prediction model, the temperature distribution and the degree of temperature drop after the completion of cooling can be obtained. can also be considered as a prediction model, and the calculation (prediction) accuracy of the learning value _K0 can be improved.

(Cooling water temperature and discharge time)
The water temperature of the cooling water discharged from the upper nozzle 44 and the lower nozzle 46 of the cooling device 40 changes depending on the time (and season) when the steel plate S is cooled. Therefore, by considering not only the water temperature of the cooling water supplied to the upper nozzle 44 and the lower nozzle 46 but also the time (and season) of cooling, an accurate temperature of the water discharged to the steel plate S is calculated. As a result, the cooling accuracy is improved.

In this way, by using the water temperature and the discharge time of the cooling water, which directly affect the temperature distribution and the degree of temperature decrease of the steel sheet S after the completion of cooling, as input variables of the prediction model, the temperature distribution and the temperature distribution after the completion of cooling can be obtained. A prediction model that also considers the degree of temperature decrease can be used, and the calculation (prediction) accuracy of the learning value _K0 can be improved.

In addition to the physical quantities directly or indirectly related to the temperature distribution of the steel sheet S after cooling, the degree of temperature decrease, or the degree of reheating, the prediction model includes the steel type, the weight of the slab, the size, the alloy Parameters such as component amounts, cooling start temperature, cooling stop temperature, and heating furnace name are also input. Prediction models can also be used, for example, Extreme Gradient Boosted Trees Regressor with early stopping, AVG Blender with gradient boosted regression trees, Random Forest, Elastic Net Regression, Neural Networks, Regression Trees, Gradient Boosting, etc. It can be generated by machine learning.

In the water-cooled heat transfer coefficient calculation step, the learned value _K0 predicted in the learned value prediction step is used to correct the reference heat transfer coefficient, as shown in the above equation (2). Calculate the coefficient.

〔Example〕
FIG. 4 is an embodiment of the present invention, and is a graph showing the result of comparing the accuracy of the learning value of the conventional method and the present invention using the back calculation learning value, and the vertical axis is the learning value predicted in the learning value prediction step. (correction value), and the horizontal axis is the back calculation learning value. In this embodiment, the learning value predicted in the learning value prediction step and the back calculation learning value are calculated using the back calculation learning value calculated back from the actual cooling stop temperature of the steel sheet S by the cooling calculation model formula, the least square error (RMSE : Root Mean Square Error) was evaluated.

The least square error between the learned value predicted by the conventional method and the inversely calculated learned value was "18.2". On the other hand, the least square error between the learned value predicted by the present invention and the inversely calculated learned value was "15.2". Therefore, it can be seen that the calculation (prediction) accuracy of the learning value _K0 is improved by using the present invention.

FIG. 5 is a graph showing the result of comparing the cooling stop accuracy (cooling stop temperature accuracy) of the conventional method and the present invention, and the vertical axis is the cooling stop temperature accuracy (cooling stop temperature accuracy = cooling stop temperature actual value - cooling stop temperature target value), and the horizontal axis is the actual cooling start temperature.

By using the method of calculating the water cooling heat transfer coefficient according to the present invention, the phenomenon that the cooling stop temperature deviates greatly (for example, ± 15 ° C. or more) as shown in part A of FIG. It can be seen that the cold stop accuracy is improved.

Table 1 shows changes in cold stop accuracy between the conventional method and the present invention. As shown in Table 1, there is no change in the average cold stop accuracy (Ave) between the conventional method and the present invention, but the standard deviation (σ) of the cold stop accuracy increased from 7.5°C to 6.9°C. It can be seen that the cold stop accuracy is improved compared to the conventional one.

Table 2 is a table showing the degree of influence (relative usefulness) of each physical quantity directly or indirectly related to the temperature distribution, the degree of temperature decrease, or the degree of reheating of the steel sheet S after cooling. This degree of influence relatively represents the degree of influence of each physical quantity when "chemical component (Si)", which has the greatest degree of influence on the prediction model, is taken as 100%.

As shown in Table 2, the cooling water discharge time, the control pattern of the cooling zone, the leveler load, and the discharge amount at the masking position (the discharge amount of the lower nozzle 46 provided with the masking device 47) are in order of influence on the prediction model. becomes larger. Therefore, among the physical quantities directly or indirectly related to the temperature distribution, the degree of temperature decrease, or the degree of reheating of the steel sheet S after cooling, the discharge amount at the masking position is preferentially input to the prediction model. Therefore, it is possible to further improve the accuracy of calculation of the learning value.

According to the method for calculating the water-cooling heat transfer coefficient of the steel plate, the method for cooling the steel plate, and the method for manufacturing the steel plate according to the embodiments described above, the temperature distribution of the steel plate S after cooling and the degree of temperature decrease Alternatively, the physical quantity directly or indirectly related to the degree of reheating (control pattern of the cooling zone, discharge amount of cooling water from the lower nozzle 46 on the most upstream side adjusted by the masking device 47, load of the leveler 30, steel plate S By using a prediction model learned using the temperature of the cooling water for cooling and the time of discharging the cooling water as input variables, it is possible to increase the accuracy of calculating the learned value _K0 of the water-cooling heat transfer coefficient. Then, the water-cooling heat transfer coefficient and the heat flux of the steel plate S are obtained using the calculated learning value _K0 , and the conveying speed of the steel plate S is determined, whereby the cooling accuracy of the steel plate S can be improved.

As described above, the method for calculating the water-cooling heat transfer coefficient of a steel plate, the method for cooling a steel plate, and the method for manufacturing a steel plate according to the present invention have been specifically described by way of embodiments and examples for carrying out the invention. It should not be limited to these descriptions and should be broadly interpreted based on the description of the claims. Further, it goes without saying that various changes and alterations based on these descriptions are also included in the gist of the present invention.

For example, in the steel plate cooling device 40 according to the embodiment, the conveying speed when the steel plate S is cooled by the cooling device 40 is determined based on the water cooling heat transfer coefficient calculated by the method for calculating the water cooling heat transfer coefficient of the steel plate. However, instead of the conveying speed of the steel plate S, for example, the flow rate of the cooling water by the upper nozzle 44 and the lower nozzle 46 or the opening degree of the upper nozzle 44 and the lower nozzle 46 when controlling the flow rate of the cooling water may be determined. good. As described above, even when the cooling water flow rate and the nozzle opening are determined instead of the conveying speed of the steel plate S, the cooling accuracy of the steel plate S can be improved.

Further, in the method of calculating the water-cooling heat transfer coefficient according to the embodiment, the correction value of the water-cooling heat transfer coefficient of the steel plate S is predicted, and the predicted correction value is used to correct the water-cooling heat transfer coefficient. Instead of, for example, a configuration may be adopted in which the water-cooling heat transfer coefficient corrected by the correction value is directly predicted.

1 Manufacturing Equipment 10 Heating Furnace 20 Rolling Mill 30 Leveler 40 Cooling Device 41 Draining Roll 42 Table Roll 43 Upper Header 44 Upper Nozzle 45 Lower Header 46 Lower Nozzle 47 Masking Device 50 Thermometer 60 Conveying Device 100 Calculating Device 101 Information Processing Device 102 Input Device 103 Output device 111 RAM
112 ROMs
112a control program 113 CPU
S steel plate

Claims (8)

A method for calculating a water-cooled heat transfer coefficient of a steel plate when cooling the steel plate with a cooling device while conveying the steel plate rolled by a rolling mill,
A parameter including at least one physical quantity directly or indirectly related to the temperature distribution, the degree of temperature decrease, or the degree of reheating of the steel plate after cooling is used as an input variable, and the related value of the water-cooling heat transfer coefficient of the steel plate is output. Predicting the relevant values for the steel sheet to be rolled by inputting the parameters of the steel sheet to be rolled into a prediction model generated from past operation data of the cooling device including the past physical quantity as a variable. and determining the water cooling heat transfer coefficient from the predicted associated value ;
A leveler is provided on the upstream side of the cooling device in the conveying direction of the steel sheet for correcting distortion of the steel sheet by rolling down the steel sheet before cooling,
The physical quantity includes a load applied to the leveler,
Calculation method of water cooling heat transfer coefficient of steel plate. The related value is a correction value for correcting the water cooling heat transfer coefficient, and the water cooling heat transfer coefficient is corrected by the predicted correction value.
A method for calculating a water cooling heat transfer coefficient of the steel plate according to claim 1. the associated value is a corrected water cooling heat transfer coefficient;
A method for calculating a water cooling heat transfer coefficient of the steel plate according to claim 1. The cooling device
a plurality of cooling zones provided along the conveying direction of the steel plate;
a nozzle provided in each cooling zone for discharging cooling water to the upper surface and the lower surface of the steel plate, respectively;
with
The physical quantity includes a cooling zone control pattern indicating a cooling zone used for cooling the steel sheet among the plurality of cooling zones,
A method for calculating a water-cooling heat transfer coefficient of the steel plate according to any one of claims 1 to 3. The cooling device
a plurality of cooling zones provided along the conveying direction of the steel plate;
a nozzle provided in each cooling zone for discharging cooling water to the upper surface and the lower surface of the steel plate, respectively;
A masking device that is provided in the most upstream nozzle in the conveying direction of the steel plate among the nozzles that discharge cooling water to the lower surface of the steel plate and adjusts the amount of cooling water discharged by the nozzle;
with
The physical quantity includes the amount of cooling water discharged by the nozzle on the most upstream side adjusted by the masking device,
A method for calculating a water-cooling heat transfer coefficient of the steel plate according to any one of claims 1 to 4. The physical quantity includes the temperature of cooling water for cooling the steel plate and the time at which the cooling water is discharged,
A method for calculating a water-cooling heat transfer coefficient of the steel plate according to any one of claims 1 to 5 . A heat flux is calculated using the water-cooling heat transfer coefficient calculated by the method for calculating a water-cooling heat transfer coefficient of a steel plate according to any one of claims 1 to 6 , and the steel plate is conveyed based on the heat flux. A method of cooling a steel plate, including the step of determining a rate. A method for producing a steel sheet, comprising the step of cooling a hot-rolled steel sheet using the steel sheet cooling method according to claim 7 .

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