METHOD FOR CONTROLLING THE WARPAGE OF METAL STRIP, METAL STRIP MANUFACTURING METHOD, AND METAL STRIP WARPAGE CONTROL DEVICE

Abstract

To provide a metal strip warpage shape control method which can control the warpage shape in which the cross-sectional shape in the plate width direction becomes a W shape and the warpage shape which is approximated by a high-order function and reduce the warpage height of a metal strip on the downstream side of a temper rolling mill.SOLUTION: There is provided a metal strip warpage shape control method for controlling the outlet side warpage shape being the warpage shape of a metal strip on the downstream side of a temper rolling mill in a metal strip manufacturing facility including: the temper rolling mill which corrects the shapes of the metal strips that are continuously conveyed; and an inlet side warpage shape measurement device which measures the inlet side warpage shape of the metal strip on the upstream side of the temper rolling mill. The metal strip warpage shape control method includes: calculating the approximation curve of the inlet side warpage shape measured by the inlet side warpage shape measurement device by using the approximation method selected from the parabolic approximation, the circular arc approximation and the envelope approximation; and setting an operational parameter of the temper rolling mill which can reduce the warpage height of the outlet side warpage shape on the basis of the calculated approximation curve.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for controlling the warpage shape of a metal strip, a method for manufacturing a metal strip, and an apparatus for controlling the warpage shape of a metal strip. [Background technology]

[0002] In continuous annealing equipment for metal strips, control of heat treatment conditions such as heating and cooling is important in order to impart required mechanical properties to the metal strip being treated. In the production of high-strength steel sheets, heat treatment conditions are often controlled by increasing the cooling rate of the metal strip and by performing a tempering treatment in which the cooled metal strip is reheated in order to improve press formability.

[0003] Continuous annealing equipment for producing high-strength steel sheets includes a heating zone, a soaking zone, and a cooling zone. Cooling methods in the cooling zone include liquid quenching, roll cooling, air-water mixture (mist) cooling, and gas jet cooling, and an appropriate cooling method is selected to control the properties of the metal strip. For example, when producing high-strength steel sheets with high tensile strength, it is effective to increase the cooling rate of the metal strip in the cooling zone. However, increasing the cooling rate of the metal strip presents a problem in that the shape of the metal strip is easily deformed due to thermal contraction of the metal strip and volume expansion associated with phase transformation of the metal structure.

[0004] In order to flatten the shape of the metal strip, shape correction is performed using a temper rolling mill located downstream of the continuous annealing facility. However, when the yield stress of the metal strip is high, it may be difficult to sufficiently flatten the shape of the metal strip even if shape correction is performed using the temper rolling mill.

[0005] Patent Document 1 discloses a temper rolling method for such high-strength steel plates, in which work rolls having an average surface roughness of more than 10.0 μm are applied to a temper rolling mill. Patent Document 2 discloses measuring the shape of a metal strip and operating a shape control actuator of the rolling mill based on the deviation between the measured shape and a target shape. Patent Document 2 also discloses using a contact-type shape meter with multiple load cells embedded in a shape measurement roll to estimate the distribution of elongation in the metal strip width direction from the distribution of contact load in the strip width direction.

[0006] Patent Document 3 discloses a method in which a shape measuring device that optically measures the shape of a steel plate is provided between a temper rolling mill and a tension leveler, and the operating conditions of the temper rolling mill and tension leveler are adjusted so that the shape of the steel plate appears flat. In Patent Document 3, a periodic pattern of light projected onto the steel plate is captured by an imaging device, and the elongation distribution (elongation difference) in the plate width direction of the steel plate is measured using an image analyzer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-176802 [Patent Document 2] Patent No. 6673285 [Patent Document 3] Japanese Patent Application Laid-Open No. 2018-65190 Summary of the Invention [Problem to be solved by the invention]

[0008] The method disclosed in Patent Document 1 performs temper rolling using work rolls having a specific surface roughness, and does not take into consideration the shape of the metal strip at the entry side of the temper rolling mill. Therefore, when the warpage height of the metal strip at the entry side of the temper rolling mill increases, the method is unable to sufficiently suppress the warpage shape by following the shape, and the warpage height of the metal strip may remain high even after temper rolling.

[0009] The method disclosed in Patent Document 2 dynamically controls the shape of a metal strip based on the shape of the metal strip measured at the delivery side of a temper rolling mill, and can stabilize the shape of the metal strip in the longitudinal direction. However, the shape meter used in Patent Document 2 estimates the distribution of elongation in the width direction of the metal strip, i.e., estimates the wave shape of the metal strip. Therefore, it is difficult to control a warpage shape that has a W-shaped cross section in the width direction, which may occur in a high-strength steel sheet after quenching, or a warpage shape that is approximated by a higher-order function.

[0010] The shape meter used in the method disclosed in Patent Document 3 also measures the distribution of elongation in the width direction of a metal strip, i.e., estimates the wave shape of the metal strip. Therefore, as with the method disclosed in Patent Document 2, it is difficult to control a warpage shape in which the cross section in the width direction of a high-strength steel sheet after quenching has a W-shape, or a warpage shape approximated by a higher-order function.

[0011] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a metal strip warpage shape control method that can control a warpage shape having a W-shaped cross section in the strip width direction or a warpage shape approximated by a higher-order function in a metal strip manufacturing facility including a temper rolling mill, and can reduce the warpage height of the metal strip downstream of the temper rolling mill, a metal strip manufacturing method using the warpage shape control method, and a metal strip warpage shape control device. [Means for solving the problem]

[0012] The means for solving the above problems are as follows. [1] A method for controlling the warpage shape of a metal strip in a metal strip manufacturing facility including a temper rolling mill for correcting the shape of a continuously transported metal strip and an inlet warpage measuring device for measuring the inlet warpage shape of the metal strip upstream of the temper rolling mill, the method comprising: calculating an approximation curve of the inlet warpage shape measured by the inlet warpage measuring device using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation; and setting operation parameters of the temper rolling mill that can reduce the warpage height of the outlet warpage shape based on the calculated approximation curve. [2] A method for controlling the warpage shape of a metal strip in a metal strip manufacturing facility including a temper rolling mill for correcting the shape of a continuously transported metal strip and an outlet warpage shape measuring device for measuring the outlet warpage shape of the metal strip downstream of the temper rolling mill, the method comprising: calculating an approximation curve of the outlet warpage shape measured by the outlet warpage shape measuring device using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation; and setting operation parameters of the temper rolling mill that can reduce the warpage height of the outlet warpage shape based on the calculated approximation curve. [3] A method for controlling the warpage shape of a metal strip in a metal strip manufacturing facility including a temper rolling mill for correcting the shape of a continuously transported metal strip and an inlet warpage measuring device for measuring the inlet warpage shape of the metal strip upstream of the temper rolling mill, the method comprising the steps of: inputting input data including the inlet warpage shape measured by the inlet warpage measuring device and at least one of operation parameters of the temper rolling mill; predicting the outlet warpage shape using a warpage shape prediction model having the outlet warpage shape as an output; calculating an approximation curve of the predicted outlet warpage shape using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation; and setting operation parameters of the temper rolling mill that can reduce the warpage height of the outlet warpage shape based on the calculated approximation curve. [4] The method for controlling the warpage shape of a metal strip according to any one of [1] to [3], wherein the manufacturing facility is a continuous annealing facility for performing heat treatment on the metal strip, and the temper rolling mill is arranged downstream of a heating zone for heating the metal strip and a cooling zone for cooling the metal strip heated in the heating zone. [5] A method for manufacturing a metal strip, comprising using the method for controlling the warpage shape of a metal strip according to any one of [1] to [3] to manufacture a metal strip having a tensile strength of 980 MPa or more. [6] A method for manufacturing a metal strip, comprising using the method for controlling the warpage shape of a metal strip according to [4] to manufacture a metal strip having a tensile strength of 980 MPa or more. [7] A metal strip warpage shape control device for controlling an outlet warpage shape, which is a warpage shape of the metal strip downstream of the temper rolling mill, in a metal strip manufacturing facility including a temper rolling mill that corrects the shape of a continuously transported metal strip and an inlet warpage shape measuring device that measures an inlet warpage shape of the metal strip upstream of the temper rolling mill, the metal strip warpage shape control device comprising: an acquiring unit that acquires the inlet warpage shape measured by the inlet warpage shape measuring device; an approximation curve calculating unit that calculates an approximation curve of the inlet warpage shape using an approximation method selected from parabolic approximation, circular arc approximation, and envelope approximation; and an operation parameter specifying unit that specifies operation parameters of the temper rolling mill based on the approximation curve so as to reduce the warpage height of the outlet warpage shape. [8] A metal strip warpage shape control device for controlling the delivery side warpage shape in a metal strip manufacturing facility including a temper rolling mill that corrects the shape of a continuously transported metal strip and an outlet warpage shape measuring device that measures the delivery side warpage shape of the metal strip downstream of the temper rolling mill, the metal strip warpage shape control device comprising: an acquisition unit that acquires the delivery side warpage shape measured by the outlet side warpage shape measuring device; an approximation curve calculation unit that calculates an approximation curve of the delivery side warpage shape using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation; and an operation parameter identification unit that identifies operation parameters of the temper rolling mill based on the approximation curve so as to reduce the warpage height of the delivery side warpage shape. [9] In a metal strip manufacturing facility including a temper rolling mill for correcting the shape of a continuously transported metal strip, and an inlet warpage shape measuring device for measuring the inlet warpage shape of the metal strip upstream of the temper rolling mill, a metal strip warpage shape control device for controlling the outlet warpage shape, which is the warpage shape of the metal strip downstream of the temper rolling mill, includes an acquisition unit for acquiring the inlet warpage shape measured by the inlet warpage shape measuring device, and an input unit including the inlet warpage shape measured by the inlet warpage shape measuring device and at least one of the operation parameters of the temper rolling mill. a warpage shape prediction unit that predicts the delivery-side warpage shape by using a warpage shape prediction model that receives data as an input and outputs the delivery-side warpage shape; an approximation curve calculation unit that calculates an approximation curve of the delivery-side warpage shape predicted by the warpage shape prediction unit by using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation; and an operation parameter identification unit that identifies operation parameters of the skin pass rolling mill that can reduce the warpage height of the delivery-side warpage shape based on the approximation curve calculated by the approximation curve calculation unit.

[10] The manufacturing facility is a continuous annealing facility that performs heat treatment on the metal strip, The warpage shape control device for a metal strip according to any one of [7] to [9], wherein the temper rolling mill is arranged downstream of a heating zone that heats the metal strip and a cooling zone that cools the metal strip heated in the heating zone. [Effects of the Invention]

[0013] By implementing the method for controlling the warpage shape of a metal strip according to the present invention, it is possible to control a warpage shape whose cross section in the strip width direction is W-shaped or a warpage shape approximated by a higher-order function, thereby reducing the warpage height of the metal strip downstream of the temper rolling mill. Furthermore, by using the method for controlling the warpage shape of a metal strip, it is possible to manufacture a metal strip with a reduced warpage height. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing a temper rolling facility as an example of a metal strip manufacturing facility in which the method for controlling the warpage shape of a metal strip according to the first embodiment can be implemented. [Figure 2] FIG. 2 is a schematic diagram of a temper rolling mill. [Figure 3] FIG. 3 is a schematic diagram showing an example of a warpage shape in the width direction of a metal strip. [Figure 4] FIG. 4 is a schematic diagram showing a state in which the warpage shape of the metal strip 1 is measured using a laser scanning type laser distance meter. [Figure 5] FIG. 5 is a schematic diagram showing how the warpage shape is measured using a plurality of laser scanning type laser distance meters. [Figure 6] FIG. 6 is a schematic diagram showing a configuration example of a warp shape control device. [Figure 7] FIG. 7 is a graph showing an approximation curve that approximates the distribution of warpage height in the sheet width direction of a metal strip. [Figure 8] FIG. 8 is a schematic diagram showing how warpage in the width direction of a metal strip is corrected by temper rolling. [Figure 9] FIG. 9 is a diagram for explaining a method for setting the setting value of the bender force of the work roll bender of the temper rolling mill. [Figure 10] FIG. 10 is a schematic diagram showing a temper rolling facility as an example of a metal strip manufacturing facility in which the method for controlling the warpage shape of a metal strip according to the second embodiment can be implemented. [Figure 11] FIG. 11 is a schematic diagram showing the configuration of a warp shape control device. [Figure 12] FIG. 12 is a schematic diagram showing a temper rolling facility as an example of a metal strip manufacturing facility in which the method for controlling the warpage shape of a metal strip according to the third embodiment can be implemented. [Figure 13] FIG. 13 is a schematic diagram showing the configuration of a warp shape control device. [Figure 14] FIG. 14 is a diagram illustrating an example of a machine learning model using a neural network. [Figure 15] FIG. 15 is a schematic diagram showing an example of continuous annealing equipment for producing cold-rolled steel sheets. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be specifically described below through embodiments of the present invention. The following embodiments are preferred examples of the present invention, and the present invention is not limited to these examples.

[0016] The method for controlling the warpage shape of a metal strip according to the embodiment of the present invention can be carried out using a metal strip manufacturing facility including a temper rolling mill that corrects the shape of a continuously transported metal strip. This metal strip manufacturing facility may be a dedicated facility (temper rolling facility) that performs temper rolling of a metal strip, or may be a manufacturing facility configured with a plurality of devices including the temper rolling mill.

[0017] For example, a continuous annealing facility that performs heat treatment on a metal strip is provided with a temper rolling mill that performs temper rolling on the heat-treated metal strip. Such a continuous annealing facility is also a metal strip manufacturing facility that can implement the warp shape control method according to this embodiment. The metal strip manufacturing facility that can implement the warp shape control method according to this embodiment is a manufacturing facility that mainly manufactures steel strips. The typical dimensions (thickness / width / length) of the steel strip are a thickness of 0.4 to 3.2 mm, a width of 700 to 1800 mm, and a length of 600 to 4000 m.

[0018] First Embodiment Fig. 1 is a schematic diagram showing a temper rolling facility 30, which is an example of a metal strip manufacturing facility in which the method for controlling the warpage shape of a metal strip according to the first embodiment can be implemented. The temper rolling facility 30 shown in Fig. 1 includes a temper rolling mill 31. The temper rolling mill 31 is a device that imparts an elongation of about 0.1 to 3.0% to the metal strip 1 to flatten the shape of the metal strip 1.

[0019] FIG. 2 is a schematic diagram of a temper rolling mill 31. FIG. 2(a) shows a side view of the temper rolling mill. FIG. 2(b) shows a front view of the temper rolling mill. A temper rolling facility 30 including the temper rolling mill 31 will be described with reference to FIGS. 1 and 2. The temper rolling facility 30 includes the temper rolling mill 31, an entry-side bridle roll 36, an entry-side tension meter 37, an exit-side tension meter 38, an exit-side bridle roll 39, an entry-side warp shape measuring device 40, a warp shape control device 50, a control computer 17, and a control controller 18.

[0020] The temper rolling mill 31 has a pair of work rolls 32a, 32b that directly contact and reduce the metal strip 1 being rolled, and backup rolls 33a, 33b that support the pair of work rolls 32a, 32b from above and below and suppress deflection of the work rolls 32a, 32b. At least one of the work rolls 32a, 32b and the backup rolls 33a, 33b is connected at one end to a drive motor via a coupling or a reducer, and the roll is rotated by the drive motor. The backup roll 33a is supported by a bearing housing (backup roll chock) 35 at the end of the shaft. A reduction device 34 adjusts the roll gap, which is the gap between the work rolls 32a and 32b, by displacing the bearing housing 35 up and down. A load detector 42 detects the rolling load of the temper rolling mill 31.

[0021] The work rolls 32a, 32b are supported by bearing boxes (work roll chocks) 43a, 43b provided at both ends of the rolls, respectively. A hydraulic device (not shown) is provided to apply force between the upper work roll chock 43a and the lower work roll chock 43b. The hydraulic system applies a bending force to the work rolls 32a, 32b by applying a force between the upper and lower work roll chocks 43a, 43b, thereby deflecting the work rolls 32a, 32b. The mechanism that deflects the work rolls 32a, 32b in this way is called a work roll bender, and the force applied between the upper and lower work roll chocks 43a, 43b is called the bender force. A mechanism that applies a force in the direction that moves the upper and lower work roll chocks 43a, 43b apart is called an increase bender, and a mechanism that applies a force in the direction that moves the upper and lower work roll chocks 43a, 43b closer together is called a decrease bender. The temper rolling mill 31 may be equipped with both an increase bender and a decrease bender mechanism. In this case, the bender force is expressed as positive or negative; for example, the increase bender force is positive, and the decrease bender force is negative.

[0022] An entry-side bridle roll 36, an entry-side tension meter 37, an exit-side tension meter 38, and an exit-side bridle roll 39 are arranged before and after the temper rolling mill 31. The entry-side bridle roll 36 and the exit-side bridle roll 39 apply an appropriate tension to the metal strip 1. The entry-side tension meter 37 and the exit-side tension meter 38 are provided between the temper rolling mill 31 and the entry-side bridle roll 36, and between the temper rolling mill 31 and the exit-side bridle roll 39, respectively. The entry-side tension meter 37 and the exit-side tension meter 38 measure the tension of the metal strip 1 on the entry side and the exit side of the temper rolling mill 31.

[0023] The temper rolling mill 31 rolls the metal strip 1 at a predetermined elongation rate. The elongation rate is the elongation rate of the metal strip 1 before and after temper rolling, and is defined as the rate of increase in the length of the metal strip 1 before and after temper rolling. The elongation rate is measured by the difference in peripheral speed between the entry bridle roll 36 and the exit bridle roll 39.

[0024] An entry-side warpage measuring device 40 for measuring the warpage shape of the metal strip 1 (hereinafter, this warpage shape will be referred to as "entry-side warpage shape") is provided upstream of the temper rolling mill 31. The entry-side warpage measuring device 40 may be provided at any position upstream of the temper rolling mill 31. However, it is preferable not to provide any equipment that significantly changes the warpage shape of the metal strip 1 between the entry-side warpage measuring device 40 and the temper rolling mill 31. For example, an annealing furnace, a cooling facility, and a rolling facility significantly change the warpage shape of the metal strip 1. For this reason, it is preferable to provide the entry-side warpage measuring device 40 between these facilities and the temper rolling mill 31.

[0025] The inlet-side warpage measuring device 40 measures the inlet-side warpage shape of the metal strip 1 to obtain information specifying the distribution of warpage height in the strip width direction of the metal strip 1. The inlet-side warpage measuring device 40 outputs the information specifying the distribution of warpage height in the strip width direction of the metal strip 1 to the warpage shape control device 50.

[0026] When the warpage shape control device 50 acquires information specifying the distribution of the warpage height in the strip width direction of the metal strip 1 from the inlet warpage shape measuring device 40, the warpage shape control device 50 calculates an approximation curve of the inlet warpage shape using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation. Then, based on the calculated approximation curve, the warpage shape control device 50 specifies operation parameters of the temper pass mill 31 that can reduce the warpage height of the warpage shape of the metal strip 1 downstream of the temper pass mill 31 (hereinafter, this warpage shape will be referred to as "delivery warpage shape"). The warpage shape control device 50 outputs the specified operation parameters of the temper pass mill 31 to the control controller 18.

[0027] The control controller 18 is a dedicated computer for executing sequence control, such as a PLC (Programmable Logic Controller). The control controller 18 sets the operating conditions of the temper rolling equipment 30 including the temper rolling mill 31, and acquires sensor information from various sensors provided in the temper rolling equipment 30. The control controller 18 sets the operating conditions of the reduction device 34 of the temper rolling mill 31 so that the elongation rate of the metal strip 1 after temper rolling coincides with a target elongation rate. Furthermore, when the control controller 18 acquires operating parameters of the temper rolling mill 31 from the warp shape control device 50, the control controller 18 sets the operating conditions of the temper rolling mill 31 based on the operating parameters.

[0028] The control computer 17 is, for example, a general-purpose computer such as a workstation or a personal computer. The control computer 17 determines various operational parameters in the temper rolling facility 30, collects sensor information from the control controller 18, and acquires and stores various information related to the operational performance of the metal strip 1. The control computer 17 also tracks the weld between the preceding metal strip and the succeeding metal strip, which are joined by a welding machine or the like on the upstream side of the temper rolling facility 30, and determines the current position of the weld.

[0029] Next, the warpage shape controlled by the method for controlling the warpage shape of a metal strip according to this embodiment will be described. Known warpage shapes of a metal strip 1 include L-warpage (warpage in the longitudinal direction of the metal strip 1) and C-warpage (warpage in the width direction of the metal strip 1). Of these, C-warpage is included in the warpage shapes controlled by the method for controlling the warpage shape of a metal strip according to this embodiment, but L-warpage is not. This is because L-warpage is constrained by the line tension when the metal strip 1 is continuously transported, making it difficult to measure L-warpage online. The C-warpage controlled by the method for controlling the warpage shape of a metal strip according to this embodiment includes not only C-warpage in which the cross-sectional shape of the metal strip 1 in the width direction is approximated by a quadratic function or a circular arc, but also warpage in which the cross-sectional shape in the width direction is W-shaped and warpage approximated by a higher-order function of third or higher order.

[0030] Warpage of the metal strip 1 in the width direction occurs when the in-plane stress generated in the width direction of the metal strip 1 due to the cooling process or the like cannot be maintained in-plane, and is displaced out-of-plane due to buckling. In contrast, a corrugated shape defect occurs when the longitudinal elongation of the metal strip 1 is distributed in the width direction, and the in-plane stress generated in the longitudinal direction of the metal strip 1 cannot be maintained in-plane, and is displaced out-of-plane due to buckling. Although both width-direction warpage and corrugation are similar in that they are out-of-plane deformations caused by buckling, the difference is that the direction of the stress that causes buckling is the width direction or the longitudinal direction.

[0031] Therefore, in the case of a corrugated shape, if tension is applied in the longitudinal direction of the metal strip 1, the difference in elongation in the width direction of the strip is absorbed, and the shape defect of the metal strip 1 becomes latent (the strip appears to change to a flat shape). On the other hand, in the case of a warped shape in the width direction, applying tension in the longitudinal direction of the metal strip 1 does not have a significant effect on the stress in the width direction. Therefore, applying tension in the longitudinal direction of the metal strip 1 does not change the warped shape of the metal strip 1 in the width direction.

[0032] The contact-type shape meter disclosed in Patent Document 2 applies a large tension (e.g., 100 to 200 MPa) between the temper rolling mill and the exit bridle roll to make any shape defects of the metal strip latent, and measures the contact load distribution in the strip width direction. That is, this contact-type shape meter measures the corrugation of the metal strip 1, but not the warpage in the strip width direction. Furthermore, the difference between the corrugation and warpage is that the displacement in the height direction of the metal strip 1 changes periodically relative to the longitudinal direction of the metal strip 1, whereas the warpage does not exhibit any periodic displacement relative to the longitudinal direction of the metal strip 1. The period of the corrugation of the metal strip 1 is often a pitch of about 0.5 to 5 m in the longitudinal direction of the metal strip.

[0033] FIG. 3 is a schematic diagram showing an example of the warpage shape in the width direction of a metal strip 1. The warpage shape shown in FIG. 3 is an example of the warpage shape measured for a metal strip made of a high-strength steel plate with a thickness of 1.2 mm and a width of 1200 mm after a cooling process by water quenching and rolling by a temper rolling mill. However, the warpage shape shown in FIG. 3 is normalized by the maximum height in the width direction. As shown in FIG. 3, when a metal strip made of a high-strength steel plate is rapidly cooled by water quenching, the warpage shape in the width direction becomes a warpage shape that is approximated by a higher-order function.

[0034] The inlet-side warpage measuring device 40 measures the inlet-side warpage shape of the metal strip 1 to obtain information for identifying the distribution of warpage heights in the width direction of the metal strip 1. The information for identifying the distribution of warpage heights in the width direction of the metal strip 1 is, for example, information showing the distribution of warpage heights at each position in the width direction of the metal strip 1, as shown in FIG. 3 . Alternatively, the inlet-side warpage measuring device 40 may approximate a curve showing the distribution of warpage heights in the width direction of the metal strip 1 using an arbitrary function and obtain coefficients for identifying the approximated function, as information for identifying the distribution of warpage heights in the width direction of the metal strip 1. The inlet-side warpage measuring device 40 may also obtain the distribution of warpage heights at each position in the width direction of the metal strip 1 by averaging the distribution of warpage heights over a range of approximately 1 to 5 m in the longitudinal direction of the metal strip 1. By averaging the warpage heights over a range of approximately 1 to 5 m in the longitudinal direction of the metal strip 1 in this way, even if the metal strip 1 includes both a warped shape and a corrugated shape, the warpage shape can be identified without including the corrugated shape.

[0035] The inlet warpage shape measuring device 40 capable of acquiring information for identifying the distribution of warpage heights at each position in the width direction of the metal strip 1 is, for example, a laser distance meter. A plurality of non-contact laser distance meters may be arranged at different positions in the width direction of the transported metal strip 1, and the warpage height at each position may be measured using the laser distance meter. For example, when measuring the warpage height of a metal strip 1 having a width of 800 to 1900 mm using laser distance meter, the number of laser distance meters arranged at different positions in the width direction is preferably 3 to 100, more preferably 10 to 20. Using fewer than three laser distance meters is undesirable because it makes it difficult to identify the warpage shape of the metal strip 1 in the width direction. Furthermore, using more than 100 laser distance meter is undesirable because it does not improve the measurement accuracy of the warpage shape and increases the equipment cost.

[0036] Fig. 4 is a schematic diagram showing a state in which the warpage shape of a metal strip 1 is measured using a laser scanning type laser distance meter. As shown in Fig. 4, a laser scanning type laser distance meter 44 may be used as the inlet warpage shape measuring device 40. By using the laser scanning type laser distance meter 44, a laser beam is scanned from above the transported metal strip 1 in the strip width direction, and the warpage height of the metal strip 1 in the strip width direction can be measured.

[0037] Fig. 5 is a schematic diagram showing a state in which a warpage shape is measured using a plurality of laser scanning type laser distance meters. As shown in Fig. 5, a plurality of laser scanning type laser distance meters 44 may be used as an inlet side warpage shape measuring device 40. In this case, a plurality of laser scanning type laser distance meters 44 are arranged in the strip width direction of the metal strip 1 to measure the warpage height in the strip width direction of the metal strip 1. This allows the inlet side warpage shape to be measured in a shorter time than with the device shown in Fig. 4.

[0038] Alternatively, a device for measuring the inlet warpage shape by a light-section method may be used as the inlet warpage shape measuring device 40. In the light-section method, a laser beam that spreads in a fan shape in the sheet width direction is irradiated from above the metal strip 1, and the light reflected from the metal strip 1 is received. The received reflected light is imaged by an image sensor to measure the warpage height of the metal strip 1. Examples of devices for measuring the inlet warpage shape by the light-section method include the LJ-X8000 series manufactured by Keyence Corporation and the Gocator manufactured by LMT Technologies.

[0039] The measurement accuracy of the warpage height of the metal strip 1 by the inlet warpage shape measuring device 40 is preferably 1 mm or less, and more preferably 0.5 mm or less. By using the inlet warpage shape measuring device 40 having a measurement accuracy of 1 mm or less, even if the upper limit of the warpage height of the metal strip 1 is set to a range of 5 to 10 mm, the warpage height of the metal strip 1 can be controlled within this range.

[0040] The measurement of the warpage height of the metal strip 1 by the inlet warpage shape measuring device 40 is preferably performed at a pitch of 1 m or less in the longitudinal direction of the metal strip 1. The measurement frequency of the warpage height for the continuously transported metal strip 1 is preferably 10 Hz or more, and more preferably 20 Hz or more. For example, in the outlet equipment of a continuous annealing line, the metal strip 1 may be transported at a speed of 600 m / min or more. Even if the metal strip 1 is transported at this transport speed, the warpage shape can be measured at a pitch of 1 m or less in the longitudinal direction of the metal strip 1 as long as the measurement frequency of the warpage shape is 10 Hz or more.

[0041] Next, the warp shape control device 50 will be described. Fig. 6 is a schematic diagram showing a configuration example of the warp shape control device 50. The warp shape control device 50 is, for example, a general-purpose computer such as a workstation or a personal computer. The warp shape control device 50 has a control unit 52, an input unit 54, an output unit 56, and a storage unit 58. The control unit 52 is, for example, a CPU, and executes a program read from the storage unit 58, causing the control unit 52 to function as an acquisition unit 60, an approximation curve calculation unit 62, and an operation parameter identification unit 64.

[0042] The input unit 54 is, for example, a keyboard, a touch panel integrated with a display, etc. The output unit 56 is, for example, an LCD or CRT display, etc. The storage unit 58 is, for example, an updatable flash memory, a built-in hard disk or a hard disk connected via a data communication terminal, an information recording medium such as a memory card, and a read / write device for the same. The storage unit 58 stores programs for the control unit 52 to execute each function, data used by the programs, etc.

[0043] Next, a description will be given of the processing executed by the acquiring unit 60, the approximation curve calculating unit 62, and the operation parameter specifying unit 64. The acquiring unit 60 acquires information specifying the distribution of warpage height in the strip width direction of the metal strip 1 as the inlet warpage shape of the metal strip 1 from the inlet warpage shape measuring device 40. The acquiring unit 60 outputs the acquired information to the approximation curve calculating unit 62.

[0044] When the approximation curve calculation unit 62 acquires information specifying the distribution of warpage height in the plate width direction of the metal strip 1, it approximates the distribution of warpage height in the plate width direction of the metal strip 1 using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation.

[0045] By using parabolic approximation, arc approximation, or envelope approximation, the approximation curve calculation unit 62 can approximate the distribution of warpage height in the width direction of the metal strip 1 to a monotonic curve having one inflection point relative to the position in the width direction of the metal strip 1. This makes it possible to obtain an approximation curve that represents the overall tendency of the warpage shape in the width direction of the metal strip 1. The approximation curve does not need to be symmetrical with respect to the center position in the width direction of the metal strip 1, but it is preferable that the approximation curve be a monotonic curve having an inflection point at the center position in the width direction of the metal strip 1.

[0046] FIG. 7 is a graph showing an approximation curve that approximates the distribution of warpage height in the width direction of the metal strip 1. In FIGS. 7(a) to 7(c), the distribution of warpage height in the width direction of the metal strip 1 is shown by a solid line, and the approximation curve that approximates this distribution is shown by a dashed line. In FIG. 7, to make the explanation of the approximation curve easier to understand, the width direction position on the horizontal axis is an actual dimension that is compressed in the horizontal direction, and the warpage height on the vertical axis is an actual dimension that is expanded in the vertical direction. Therefore, FIG. 7 does not show the actual distribution of warpage height in the width direction of the metal strip 1, but shows a distribution of warpage height that is exaggerated and higher than the actual warpage height.

[0047] 7(a) is a graph showing an approximation curve obtained by approximating the distribution of warpage height in the sheet width direction of the metal strip 1 using a parabolic (quadratic curve) approximation. Parabolic approximation is an approximation method in which the distribution of warpage height is approximated by a quadratic curve in a coordinate system formed by the position in the sheet width direction of the metal strip 1 and the warpage height. The approximation curve obtained by parabolic approximation can be obtained by applying a known method such as the least squares method.

[0048] 7(b) is a graph showing an approximation curve obtained by approximating the distribution of warpage height in the sheet width direction of the metal strip 1 with a circular arc. The circular arc approximation is an approximation method in which the distribution of warpage height is approximated by a circular arc in a coordinate system formed by the position in the sheet width direction of the metal strip 1 and the warpage height. The approximation curve obtained by the circular arc approximation can also be obtained by applying a known method such as the least squares method.

[0049] FIG. 7(c) is a graph showing an approximation curve obtained by envelope approximation of the distribution of warpage height in the sheet width direction of the metal strip 1. An envelope generally refers to a curve that is tangent to all of a family of curves. The warpage shape controlled by the method for controlling warpage shape of a metal strip according to this embodiment includes a plurality of curves that can be approximated by higher-order functions for the distribution of warpage height of the metal strip 1, and therefore the envelope is a curve that is tangent to all of these curves. Specifically, the envelope approximation curve is a curve that is tangent to all of the peaks that indicate the warpage height in the sheet width direction of the metal strip 1.

[0050] As shown in Figures 7(a) to 7(c), whether the approximation method, i.e., parabolic approximation, arc approximation, or envelope approximation, is used, the approximated curve is a monotonic curve that represents the overall tendency of the warpage shape in the width direction of the metal strip 1. Therefore, even if the distribution of the warpage height in the width direction of the metal strip 1 is a higher-order curve, such as a W-shape, it is possible to easily distinguish between areas of high warpage height and areas of low warpage height in the metal strip 1 by calculating the approximated curve. That is, when the approximated curve has a downward convex shape, it indicates that the warpage height at the widthwise end portion is relatively high compared to the widthwise center portion, and when the approximated curve has an upward convex shape, it indicates that the warpage height at the widthwise end portion is relatively low compared to the widthwise center portion. Since the overall tendency of the warpage shape can be easily determined by calculating the approximated curve, it is possible to easily identify the operation parameters of the temper pass mill 31 that can reduce the delivery side warpage shape of the metal strip 1 downstream of the temper pass mill 31 by using the approximated curve.

[0051] Referring again to Fig. 6, after calculating the approximate curve by the above-mentioned method, the approximate curve calculation unit 62 outputs the approximate curve to the operation parameter specification unit 64. The operation parameter specification unit 64 specifies the operation parameters of the temper rolling mill 31 that can reduce the warpage height of the delivery side warpage shape. The operation parameters of the temper rolling mill 31 are set values ​​of the operation conditions that affect the warpage shape of the metal strip 1 among the operation conditions of the temper rolling mill 31.

[0052] The operation parameter specifying unit 64 specifies, as an operation parameter of the temper rolling mill 31, for example, a set value of the bender force of the work roll bender, which is a shape control actuator of the temper rolling mill 31. The work roll bender is a shape control actuator that applies a bending force to the work rolls 32a, 32b to adjust the deflection of the work rolls 32a, 32b. By adjusting the deflection of the work rolls 32a, 32b using the work roll bender, a distribution of rolling load is formed on the work rolls 32a, 32b in the strip width direction of the metal strip 1. By temper rolling the metal strip 1 with the work rolls 32a, 32b on which this rolling load distribution has been formed, the corrugation of the metal strip 1 after temper rolling is corrected.

[0053] The inventors have found that, similar to the corrugation, the warpage shape in the width direction of the metal strip 1 can also be corrected by temper rolling the metal strip 1 with the work rolls 32a, 32b having a rolling load distribution formed thereon. Specifically, the inventors have found that the warpage height in the width direction of the metal strip 1 can be reduced by adjusting the bender force of the work roll bender so that the rolling load is increased at positions where the warpage height in the width direction of the metal strip 1 is large.

[0054] FIG. 8 is a schematic diagram showing how warpage in the width direction of a metal strip 1 is corrected by temper rolling. In FIG. 8, the height of the warpage in the width direction of the metal strip 1 is shown higher than the actual height of the warpage to explain the effect of the work roll bender. FIG. 8(a) is a schematic diagram showing the state of a metal strip 1 in which warpage of a generally uniform amplitude has been formed in the width direction before temper rolling. When a specific bender force is set and deflection occurs in the work roll 32a, a distribution of unit width load (rolling load applied per unit width of the metal strip 1) occurs in the width direction of the metal strip 1 on the work roll 32a. For example, in the work roll 32a shown in FIG. 8(a), the unit width load near the width ends of the metal strip 1 is smaller than that at the width center.

[0055] Figure 8(b) is a schematic diagram showing the state of a metal strip 1 having a warp of approximately uniform amplitude in the strip width direction after being temper rolled. When temper rolling the metal strip 1 with work rolls having such a distribution of unit width load, as shown in Figure 8(b), the warp height can be reduced in the strip width center where the unit width load is large, but the warp height cannot be reduced near the strip width edges where the unit width load is small. This is thought to be because, within the roll bite, the curvature in the strip width direction is restrained by the work rolls, and bending stress is generated inside the metal strip 1 so as to flatten the curvature in the strip width direction. However, the magnitude of the bending stress generated inside is affected by the magnitude of the unit width load, so the bending stress near the strip width edges is relatively reduced, and as a result, the warp height near the strip width edges does not decrease.

[0056] 9A and 9B are diagrams illustrating a method for setting the setting value of the bender force of the work roll bender of the temper rolling mill 31. FIG. 9A is a schematic diagram showing the distribution of the warpage height in the strip width direction of the metal strip 1 obtained from the inlet warpage shape measuring device 40. FIG. 9B is an envelope approximation curve of the inlet warpage shape calculated by the approximation curve calculation unit 62.

[0057] The approximation curve calculation unit 62 converts the warpage shape in the sheet width direction, which is represented by a high-order curve as shown in Fig. 9(a), into a smooth approximation curve as shown in Fig. 9(b). As a result, it can be seen that the warpage shape in the sheet width direction shown in Fig. 9(a) is higher in the vicinity of the sheet width ends than in the sheet width center as a whole.

[0058] The operational parameter specifying unit 64 specifies a set value of the bender force of the work roll bender based on the approximation curve calculated by the approximation curve calculation unit 62. Specifically, the operational parameter specifying unit 64 specifies a set value of the bender force of the work roll bender that increases the rolling load of the work roll near the strip width ends where the camber height is high and decreases the rolling load of the work roll at the strip width center where the camber height is low. In this way, the operational parameter specifying unit 64 specifies a set value of the bender force of the work roll bender in association with the overall tendency of the camber shape specified by the approximation curve.

[0059] 9(c) is a schematic diagram showing the shape of the warpage in the width direction of the metal strip 1 that has been temper rolled by the temper rolling mill after the setting value of the bender force set by the operation parameter specifying unit 64 has been reflected. As shown in FIG. 9(c), by temper rolling the metal strip 1 by the temper rolling mill 31 in which the setting value of the bender force of the work rolls has been reflected, temper rolling can be performed with a rolling load according to the warpage height in the width direction of the metal strip 1, and the warpage height near both ends where the warpage height is high can be significantly reduced.

[0060] However, the operational parameters identified by the operational parameter identifying unit 64 are not limited to the bender force of the work roll bender, and the operational parameters of other shape control actuators capable of controlling the deflection deformation of the work rolls and the distribution of the roll gap in the strip width direction may be identified. For example, operational parameters of shape control actuators capable of changing the distribution of the roll gap in the strip width direction of the metal strip in a gentle curve may be identified, such as the hydraulic pressure of a variable crown roll that can adjust the roll crown with hydraulic pressure, the roll shift amount that shifts the work rolls or intermediate rolls in the axial direction, and the pushing force of each segment of the divided backup roll.

[0061] The operation parameter specifying unit 64 outputs the specified operation parameters to the control controller 18. The control controller 18 sets the acquired operation parameters as the operation conditions of the temper rolling mill 31. In this way, the operation parameters specified by the operation parameter specifying unit 64 are set in the temper rolling mill 31. Then, by temper rolling the metal strip 1 using the temper rolling mill 31 in which the parameters are set as the operation conditions, it is possible to control the warpage shape in the width direction of the metal strip 1, and it is possible to manufacture a metal strip 1 in which the warpage height in the width direction is reduced downstream of the temper rolling mill 31.

[0062] The method for controlling the warpage shape of a metal strip according to the first embodiment performs feedforward control using the inlet warpage shape. By performing feedforward control, it is possible to quickly control the warpage height of the outlet warpage shape of the metal strip 1 so as to be low.

[0063] Although the entry-side warpage shape of the metal strip 1 changes due to the temper rolling by the temper rolling mill 31, when the elongation rate imparted to the metal strip 1 by the temper rolling mill 31 is small, the warpage shape of the metal strip 1 does not change significantly before and after the temper rolling. In such a case, even if the metal strip 1 is temper rolled, the overall warpage tendency of the entry-side warpage shape of the metal strip 1 does not change. Therefore, it is possible to identify operation parameters of the temper rolling mill 31 that can reduce the warpage height of the delivery-side warpage shape based on the approximation curve of the entry-side warpage shape. For this reason, the first embodiment, in which the operation parameters of the temper rolling mill are set based on the entry-side warpage shape, is not preferably applied when the elongation rate imparted to the metal strip 1 by the temper rolling mill 31 is large. The first embodiment is preferably applied when the elongation rate imparted to the metal strip 1 by the temper rolling mill 31 is 0.3% or less.

[0064] Furthermore, it is preferable that the control controller 18 can set the operation parameters of the temper rolling mill 31 during the production of the metal strip 1. Specifically, during the production of the metal strip 1, the entry-side warpage shape measuring device 40 measures the warpage shape of the metal strip 1 at any time, the warpage shape control device 50 calculates an approximation curve of the entry-side warpage shape, and the set values ​​of the operation parameters of the temper rolling equipment 30 that can reduce the warpage height of the delivery-side warpage shape are output to the control controller 18, and the set values ​​can be set and updated as needed. In this case, the control controller 18 calculates the time at which the position of the warpage shape measured by the entry-side warpage shape measuring device 40 reaches the temper rolling mill 31, using the tracking information of the weld generated by the control computer 17 and the transport speed of the metal strip 1. Then, at the timing when the position of the warpage shape measured by the entry-side warpage shape measuring device 40 reaches the temper rolling mill 31, the control controller 18 changes the production conditions to the operation parameters of the temper rolling equipment 30 set by the operation parameter specifying unit 55. This makes it possible to reduce the height of the warp on the delivery side of the metal strip 1 across the length of the metal strip 1.

[0065] <Second embodiment> Fig. 10 is a schematic diagram showing a temper rolling facility 70, which is an example of a metal strip manufacturing facility in which the method for controlling a warpage shape of a metal strip according to the second embodiment can be implemented. In the temper rolling facility 70 shown in Fig. 10, the same components as those in the temper rolling facility 30 shown in Fig. 1 are denoted by the same reference numerals, and their description will be omitted. The temper rolling facility 70 differs from the temper rolling facility 30 shown in Fig. 1 in that it has an outlet warpage shape measuring device 41 instead of the entry warpage shape measuring device 40 and a warpage shape control device 51 instead of the warpage shape control device 50.

[0066] An outlet warpage measuring device 41 for measuring the outlet warpage shape of the metal strip 1 is provided downstream of the temper rolling mill 31. The outlet warpage measuring device 41 measures the outlet warpage shape of the metal strip 1 to obtain information for specifying the distribution of warpage height in the strip width direction of the metal strip 1. The outlet warpage measuring device 41 may be the same as the inlet warpage measuring device 40, and is, for example, a laser distance meter, a laser scanning type laser distance meter, or a warpage measuring device using a light cutting method. The outlet warpage measuring device 41 outputs information for specifying the distribution of warpage height in the strip width direction of the metal strip 1 to a warpage shape control device 51.

[0067] The warpage shape control device 51, upon receiving information specifying the distribution of the warpage height in the strip width direction of the metal strip 1 from the delivery warpage shape measuring device 41, calculates an approximation curve of the delivery warpage shape. Based on the calculated approximation curve, the warpage shape control device 51 specifies operation parameters of the temper rolling mill 31 that can reduce the warpage height of the delivery warpage shape. The warpage shape control device 51 outputs the specified operation parameters of the temper rolling mill 31 to the control controller 18.

[0068] Fig. 11 is a schematic diagram showing the configuration of a warp shape control device 51. In the warp shape control device 51 shown in Fig. 11, the same components as those in the warp shape control device 50 shown in Fig. 6 are denoted by the same reference numerals, and the description thereof will be omitted.

[0069] The warp shape control device 51 is also a general-purpose computer such as a workstation or a personal computer, and includes a control unit 53, an input unit 54, an output unit 56, and a storage unit 58. The control unit 53 is, for example, a CPU, and executes a program read from the storage unit 58, thereby causing the control unit 53 to function as an acquisition unit 61, an approximation curve calculation unit 62, and an operation parameter specification unit 64.

[0070] Next, a description will be given of the processing executed by the acquisition unit 61. The acquisition unit 61 acquires information specifying the distribution of warpage height in the strip width direction of the metal strip 1 as the delivery-side warpage shape of the metal strip 1 from the delivery-side warpage shape measuring device 41. The acquisition unit 61 outputs the acquired information to the approximation curve calculation unit 62. The processing executed by the approximation curve calculation unit 62 and the operation parameter identification unit 64 is the same as in the first embodiment.

[0071] The operation parameter specifying unit 64 outputs the specified operation parameters to the control controller 18. The control controller 18 sets the acquired operation parameters as the operation conditions of the temper rolling mill 31. In this way, the operation parameters specified by the operation parameter specifying unit 64 are set in the temper rolling mill 31. Then, by temper rolling the metal strip 1 using the temper rolling mill 31 in which the parameters have been set, the warpage shape in the strip width direction can be controlled, and a metal strip 1 with a reduced warpage height in the strip width direction downstream of the temper rolling mill 31 can be manufactured.

[0072] The method for controlling the warpage shape of a metal strip according to the second embodiment performs feedback control using the delivery warpage shape. In the feedback control, a dead time occurs between measuring the warpage shape of the metal strip 1 and setting the operating conditions of the temper pass mill 31. Therefore, the responsiveness of the method for controlling the warpage shape of a metal strip according to the second embodiment is inferior to that of the first embodiment. On the other hand, in the feedback control, the delivery warpage shape, which is the control target, is measured using the delivery warpage shape measuring device 41. Therefore, the method for controlling the warpage shape of a metal strip according to the second embodiment can be applied to a manufacturing facility for a metal strip 1 including the temper pass mill 31, regardless of the elongation rate imparted by the temper pass mill 31.

[0073] <Third embodiment> Fig. 12 is a schematic diagram showing a temper rolling facility 72, which is an example of a metal strip manufacturing facility in which the method for controlling the warpage shape of a metal strip according to the third embodiment can be implemented. In the temper rolling facility 72 shown in Fig. 12, the same components as those in the temper rolling facility 30 shown in Fig. 1 or the temper rolling facility 70 shown in Fig. 10 are denoted by the same reference numerals, and their description will be omitted.

[0074] The temper rolling facility 72 shown in Fig. 12 differs from the temper rolling facility 30 shown in Fig. 1 in that it has a delivery side warpage shape measuring device 41 and a warpage shape control device 80 instead of the warpage shape control device 50. The delivery side warpage shape measuring device 41 is the same as the delivery side warpage shape measuring device 41 of the temper rolling facility 70 shown in Fig. 10.

[0075] An entry-side warpage measuring device 40 for measuring the entry-side warpage shape of the metal strip 1 is provided upstream of the temper rolling mill 31, and an exit-side warpage measuring device 41 for measuring the exit-side warpage shape of the metal strip 1 is provided downstream of the temper rolling mill 31. The entry-side warpage measuring device 40 measures the entry-side warpage shape of the metal strip 1 to obtain information for specifying the distribution of warpage height in the strip width direction of the metal strip 1. The entry-side warpage measuring device 40 outputs the obtained information for specifying the distribution of warpage height in the strip width direction of the metal strip 1 to the warpage shape control device 80 and the controller 18.

[0076] The delivery-side warpage measuring device 41 measures the delivery-side warpage shape of the metal strip 1 to obtain information specifying the distribution of warpage height in the strip width direction of the metal strip 1. The delivery-side warpage measuring device 41 outputs information specifying the distribution of warpage height in the strip width direction of the metal strip 1 to the control controller 18. The control computer 17 obtains and stores the sensor information including the entry-side warpage shape and the delivery-side warpage shape obtained by the control controller 18 as information on the operational performance of the metal strip 1.

[0077] The warpage shape control device 80 acquires information specifying the distribution of warpage heights in the strip width direction of the metal strip 1 from the entry warpage shape measuring device 40. The warpage shape control device 80 also acquires at least one of the operation parameters of the temper rolling mill 31 from the control computer 17 via the control controller 18. The operation parameters of the temper rolling mill 31 are set values ​​of operation conditions that affect the warpage shape of the metal strip 1 among the operation conditions of the temper rolling mill 31. The warpage shape control device 80 receives input data including the entry warpage shape and at least one of the operation parameters, and predicts the delivery warpage shape using a warpage shape prediction model that outputs the delivery warpage shape.

[0078] The warp shape control device 80 calculates an approximation curve of the predicted delivery side warp shape. Based on the calculated approximation curve, the warp shape control device 80 specifies operation parameters of the temper rolling mill 31 that can reduce the warp height of the delivery side warp shape. The warp shape control device 80 outputs the set operation parameters of the temper rolling mill 31 to the control controller 18.

[0079] Fig. 13 is a schematic diagram showing the configuration of a warp shape control device 80. In the warp shape control device 80, the same components as those in the warp shape control device 50 shown in Fig. 6 are given the same reference numerals, and the description thereof will be omitted.

[0080] The warpage shape control device 80 is also a general-purpose computer such as a workstation or a personal computer. The warpage shape control device 80 includes a control unit 82, an input unit 54, an output unit 56, and a memory unit 84. The control unit 82 is, for example, a CPU, and executes a program read from the memory unit 84 to cause the control unit 82 to function as an acquisition unit 86, a warpage shape prediction unit 88, a determination unit 90, an approximate curve calculation unit 92, an operation parameter identification unit 94, and a warpage shape prediction model generation unit 96. The memory unit 84 is, for example, an updatable flash memory, a built-in hard disk or a hard disk connected via a data communication terminal, a memory card, or other information recording medium and a read / write device for the information recording medium. The memory unit 84 stores programs for the control unit 82 to execute various functions, data used by the programs, and the like.

[0081] The storage unit 84 further stores a database 98 and a warpage shape prediction model 99. The database 98 stores a data set, each set including at least one of the measured values ​​of the inlet-side warpage shape, the measured values ​​of the outlet-side warpage shape, and the operation parameters of the metal strip 1 previously produced in the temper rolling facility 72. These measured values ​​and operation parameters are collected and stored in the control computer 17, and are acquired from the control computer 17 via the control controller 18. The warpage shape prediction model 99 is created in advance by the warpage shape prediction model generation unit 96 and stored in the storage unit 84.

[0082] The warpage shape prediction model 99 is a trained machine learning model that receives input data including, for example, at least one of an inlet warpage shape and an operation parameter, and outputs an outlet warpage shape. When the inlet warpage shape is information specifying the distribution of warpage height in the strip width direction of the metal strip 1, the input data input to the learning model includes values ​​of warpage height at each position in the strip width direction and at least one operation parameter. When the inlet warpage shape is a function approximating the distribution of warpage height in the strip width direction of the metal strip 1, the input data input to the learning model includes coefficients specifying the function and at least one operation parameter.

[0083] When outputting information specifying the distribution of warpage heights in the strip width direction of the metal strip 1 as the delivery side warpage shape, a warpage shape prediction model that outputs the warpage heights at each position in the strip width direction is prepared in advance. When outputting a function approximating the warpage heights in the strip width direction of the metal strip 1 as the delivery side warpage shape, a warpage shape prediction model that outputs each coefficient that specifies the function is prepared in advance.

[0084] Next, the processes executed by the acquiring unit 86, the warpage shape predicting unit 88, the determining unit 90, the approximation curve calculating unit 92, the operation parameter specifying unit 94, and the warpage shape predictive model generating unit 96 will be described. The acquiring unit 86 acquires information specifying the distribution of warpage heights in the strip width direction of the entry-side warpage shape as the entry-side warpage shape of the metal strip 1 from the entry-side warpage shape measuring device 40. The acquiring unit 86 also acquires at least one of the operation parameters of the temper rolling mill 31 from the control computer 17 via the control controller 18. The acquiring unit 86 outputs at least one of the entry-side warpage shape and the operation parameter to the warpage shape predicting unit 88.

[0085] When the warpage shape prediction unit 88 acquires at least one of the inlet-side warpage shape and the operation parameters, it reads out a warpage shape prediction model from the storage unit 84, inputs the inlet-side warpage shape and at least one of the operation parameters into the warpage shape prediction model, and outputs the delivery-side warpage shape. In this way, the warpage shape prediction unit 88 predicts the delivery-side warpage shape.

[0086] The warpage shape prediction unit 88 outputs the predicted delivery-side warpage shape to the determination unit 90. The determination unit 90 determines whether the predicted delivery-side warpage shape is equal to or smaller than a preset reference value (target warpage value). The reference value may be acquired from the control computer 17 via the acquisition unit 86 and the control controller 18, or may be stored in advance in the storage unit 84 and read out from the storage unit 84. When the determination unit 90 determines that the delivery-side warpage shape predicted by the warpage shape prediction unit 88 exceeds the reference value, the determination unit 90 outputs the predicted delivery-side warpage shape to the approximation curve calculation unit 92.

[0087] On the other hand, when it is determined that the delivery warpage shape predicted by the warpage shape prediction unit 88 does not exceed the reference value, the determination unit 90 discards the predicted delivery warpage shape without outputting it to the approximation curve calculation unit 92. By the determination unit 90 thus discarding the delivery warpage shape, the current operating conditions of the skin pass rolling mill 31 are maintained.

[0088] When the approximation curve calculation unit 92 acquires the predicted delivery side warpage shape from the determination unit 90, it calculates an approximation curve that approximates the predicted delivery side warpage shape using parabolic approximation, arc approximation, or envelope approximation. The approximation curve calculation unit 92 outputs the calculated approximation curve to the operation parameter specification unit 94. The operation parameter specification unit 94 specifies operation parameters of the temper rolling mill 31 that can reduce the warpage height of the predicted delivery side warpage shape. The method of calculating the approximation curve by the approximation curve calculation unit 92 and the method of specifying the operation parameters of the temper rolling mill 31 by the operation parameter specification unit 94 are the same as those in the first embodiment.

[0089] The operation parameter specifying unit 94 outputs the specified operation parameters to the control controller 18. The control controller 18 changes the operation conditions of the temper rolling mill 31 using the acquired operation parameters. In this way, the operation parameters specified by the operation parameter specifying unit 94 are reflected in the operation conditions of the temper rolling mill 31. Then, by temper rolling the metal strip 1 using the temper rolling mill 31, the warpage shape in the strip width direction of the metal strip 1 is controlled, and a metal strip with a reduced warpage height in the strip width direction downstream of the temper rolling mill 31 can be manufactured.

[0090] In the method for controlling the warpage shape of a metal strip according to the third embodiment, the delivery side warpage shape, which is the target of control, is predicted using the entry side warpage shape, and set values ​​of the operation parameters of the temper pass mill 31 that can reduce the warpage height in the delivery side warpage shape are identified. Therefore, the method for controlling the warpage shape of a metal strip according to the third embodiment can be applied to a manufacturing facility for a metal strip 1 including the temper pass mill 31, regardless of the elongation rate imparted by the temper pass mill 31. Furthermore, since set values ​​of the operation parameters of the temper pass mill 31 are identified at the timing when at least one of the entry side warpage shape and the operation parameters of the temper pass mill 31 is acquired, there is no dead time as occurs in the second embodiment. Therefore, the region of the metal strip 1 where the delivery side warpage shape is not controlled and becomes inappropriate is shorter than in the second embodiment.

[0091] In the third embodiment, the warp shape control device 80 includes the determining unit 90. However, the warp shape control device 80 does not necessarily need to include the determining unit 90. In this case, the warp shape prediction unit 88 outputs the predicted delivery warp shape to the approximation curve calculation unit 92. The approximation curve calculation unit 92 calculates an approximation curve of the delivery warp shape, and the operation parameter specification unit 94 specifies operation parameters that can reduce the warp height based on the calculated approximation curve. By changing the operation conditions of the temper pass mill 31 using the specified operation parameters, a metal strip with a reduced warp height in the strip width direction can be manufactured downstream of the temper pass mill 31. As described above, even without the determining unit 90, a metal strip with a reduced warp height in the strip width direction can be manufactured downstream of the temper pass mill 31, just like the case where the determining unit 90 is included.

[0092] Next, a method for generating a warpage shape prediction model by the warpage shape prediction model generating unit 96 will be described. In this embodiment, an entry-side warpage measuring device 40 for measuring the entry-side warpage shape of the metal strip upstream of the temper rolling mill 31 and an exit-side warpage measuring device 41 for measuring the exit-side warpage shape are used to obtain actual data on the entry-side warpage shape and the exit-side warpage shape. The control computer 17 generates tracking information on the welded portion of the metal strip 1. Therefore, by using the tracking information and information on the conveying speed of the metal strip 1, the control computer 17 obtains and stores the entry-side warpage shape and the exit-side warpage shape in association with the distance from the welded portion at the front end of the metal strip 1. In this case, since the temper rolling mill 31 applies elongation to the metal strip 1, it is preferable to correct the position from the welded portion at the front end measured by the exit warpage measuring device 41 in accordance with the elongation rate of the temper rolling mill 31. Furthermore, the control computer 17 acquires and stores the operation parameters of the temper rolling mill 31 in association with the distance from the leading end weld of the metal strip 1.

[0093] The acquiring unit 86 acquires data sets from the control computer 17 via the control controller 18, each set including measurement values ​​of the entry warpage shape and the delivery warpage shape at positions that are the same distance from the front end weld of the metal strip 1 and at least one of the operation parameters of the temper pass mill 31 when the positions pass through the temper pass mill 31. The acquiring unit 86 stores the acquired data sets in a database 98 of the storage unit 84. The database 98 preferably stores 200 or more data sets, and more preferably stores 1000 or more data sets.

[0094] Furthermore, it is preferable that the acquisition unit 86 acquires the above-mentioned data sets from the leading weld (e.g., within 20 m of the leading weld), the steady state portion, and the tail weld (e.g., within 20 m of the tail weld) of the metal strip 1. For metal products, whether or not a product can be shipped is conventionally determined by inspection of the leading, steady state, and tail weld portions. Therefore, it is preferable to acquire data sets from the leading weld, steady state, and tail weld, respectively, to accommodate these inspections.

[0095] Furthermore, it is preferable that the acquisition unit 86 acquires data sets covering the entire length of the metal strip 1 from the leading weld to the trailing weld of the metal strip 1 at a predetermined interval. The interval for acquiring the data sets is preferably set within a range of 5 m to 20 m. In this way, data sets covering the entire length of the metal strip 1 are stored in the database 98, and a warpage shape prediction model is created using the data sets, thereby making it possible to predict the delivery warpage shape with high accuracy. Furthermore, the acquisition unit 86 may set a certain number of data sets as an upper limit and appropriately update the data sets stored in the database 98 within this upper limit.

[0096] The warpage shape prediction model generating unit 96 uses the data set stored in the database 98 to input data including the inlet-side warpage shape and at least one of the operation parameters, and generates a warpage shape prediction model that outputs the outlet-side warpage shape. If the warpage shape prediction model is a trained machine learning model, the warpage shape prediction model generating unit 96 trains the machine learning model using the data set stored in the database 98 as training data, thereby generating a trained machine learning model. As the machine learning model, a commonly used neural network (including deep learning, convolutional neural network, etc.), decision tree learning, random forest, support vector regression, etc. may be used. Alternatively, an ensemble model combining multiple models may be used.

[0097] FIG. 14 is a diagram showing an example of a machine learning model using a neural network. A warpage shape prediction model can be generated, for example, using a machine learning model using a general neural network as shown in FIG. 14. L1, L2, and L3 in FIG. 14 are the input layer, middle layer, and output layer, respectively. In particular, deep learning using a multi-layered neural network eliminates the problem of multicollinearity and allows other operational parameters correlated with the warpage shape of the metal strip 1 to be freely selected as inputs, thereby improving the prediction accuracy of the outlet warpage shape of the metal strip 1. As shown in FIG. 14, the neural network can have two or three middle layers and 18 to 512 nodes, and a sigmoid function can be used as the activation function. The number of nodes in the output layer can be set to match the number of numerical values ​​to be output by the warpage shape prediction model. For example, if the warpage shape prediction model outputs the warpage height at each position in the strip width direction, the number of output layers can be set to the number of positions in the strip width direction at which the warpage height is specified. Furthermore, if the warpage shape prediction model outputs a function that approximates the warpage height, the number of output layers may be set to the number of coefficients for specifying the function.

[0098] Alternatively, machine learning may be performed by dividing the data set stored in the database 98 into training data and test data. By dividing the data set into training data and test data in this way, the warpage prediction model generation unit 96 can learn the weight coefficients of the neural network using the training data, and generate a warpage prediction model while changing the structure of the neural network (the number of intermediate layers and the number of nodes) so as to increase the accuracy rate of the exit warpage shape in the test data. By generating such a warpage prediction model, the accuracy of estimating the exit warpage shape by the warpage prediction model 99 can be improved.

[0099] Furthermore, the weighting coefficients of the warpage shape prediction model 99 may be updated, and the error propagation method may be used for updating the weighting coefficients. Furthermore, the warpage shape prediction model 99 may be updated to a new warpage shape prediction model by re-learning, for example, every six months or every year. By updating the warpage shape prediction model using a data set including the latest data, even if the condition of the skin pass rolling mill 31 changes over time, the latest condition can be reflected in the warpage shape prediction model.

[0100] In the first to third embodiments, the warp shape control device 50 (51, 80), the control controller 18, and the control computer 17 are each separate devices, but this is not limiting. The control controller 18 and the control computer 17 may be one device, or the control controller 18 and the warp shape control device 50 (51, 80) may be one device. Furthermore, the warp shape control device 50 (51, 80), the control controller 18, and the control computer 17 may be one device.

[0101] As described above, the method for controlling warpage of a metal strip according to this embodiment can reduce the warpage height of a metal strip having a W-shaped cross section in the width direction or a warpage shape approximated by a high-order function. A W-shaped cross section in the width direction or a warpage shape approximated by a high-order function tends to occur in a high-strength steel sheet after quenching. For this reason, the method for controlling warpage of a metal strip according to this embodiment is preferably applied to the production of a metal strip having a tensile strength of 980 MPa or more.

[0102] Next, a continuous annealing facility 100 in which the warpage shape control methods for a metal strip according to the first to third embodiments can be implemented will be described. Fig. 15 is a schematic diagram showing an example of a continuous annealing facility 100 for producing a cold-rolled steel sheet. The arrow in Fig. 15 indicates the traveling direction of a metal strip 1.

[0103] The continuous annealing facility 100 is roughly divided into an entry facility 20, a furnace facility 21, and an exit facility 24. The temper rolling facility 30 is provided in the exit facility 24. The continuous annealing facility 100 including the temper rolling facility 30 is another example of a manufacturing facility for a metal strip 1 in which the method for controlling the warpage shape of a metal strip 1 according to the first embodiment can be implemented. When the second embodiment is applied to the continuous annealing facility 100, the temper rolling facility 30 can be replaced with a temper rolling facility 70, and when the third embodiment is applied to the continuous annealing facility 100, the temper rolling facility 30 can be replaced with a temper rolling facility 72. The operation of the continuous annealing facility 100 is controlled by a control computer 17 and a control controller 18.

[0104] The entry-side equipment 20 has a payoff reel 2, a welding machine 3, and an entry-side looper 4. The furnace body equipment 21 is composed of an annealing equipment 22 and a reheating equipment 23. The annealing equipment 22 has a heating zone 6, a soaking zone 7, and a cooling zone 8, and may have a preheating zone 5 upstream of the heating zone 6. The reheating equipment 23 has a reheating zone 9, an overaging zone 10, and a final cooling zone 11, and an induction heating device is arranged in the reheating zone 9. The exit-side equipment 24 has an exit-side looper 12, an inspection table 14, and a tension reel 15.

[0105] Heating zone 6 is equipped with equipment for raising the temperature of metal zone 1, and heats it to a preset temperature in the range of approximately 600 to 900°C depending on the chemical composition of metal zone 1. Direct flame or radiant combustion burners are used in heating zone 6. Soaking zone 7 is equipped with equipment for maintaining metal zone 1 at a predetermined temperature. The equipment for maintaining metal zone 1 at a predetermined temperature has a heating capacity sufficient to compensate for the heat dissipated by the furnace body.

[0106] The cooling zone 8 is equipped with equipment for cooling the metal strip 1 to a predetermined temperature, and cooling methods used in this equipment include liquid cooling, gas jet cooling, roll cooling, and mist cooling (gas-liquid mixed cooling). Liquid cooling is often performed by water quenching. Water cooling is a cooling method in which the metal strip 1 is immersed in an immersion water tank installed downstream of the soaking zone 7. Gas jet cooling is a cooling method in which gas is sprayed from a nozzle onto the surface of the metal strip 1. Roll cooling is a cooling method in which the metal strip 1 is cooled by contacting it with a water-cooled roll. Mist cooling is a cooling method in which water is sprayed in a fine mist and the cooling is carried out by absorbing the heat of vaporization. In mist cooling, the size of the sprayed water droplets is often about 0.1 to 1 mm.

[0107] The reheating equipment 23 is disposed downstream of the cooling zone 8, and after the metal strip 1 is cooled to a predetermined temperature in the cooling zone 8, it is reheated to a temperature of about 300 to 400°C using an induction heating device or the like disposed in the reheating zone 9. The overaging zone 10 is equipment that performs overaging treatment by holding the reheated metal strip 1 for a predetermined time. The final cooling zone 11 is equipment that performs final cooling of the overaged metal strip 1 to near room temperature. However, some continuous annealing facilities do not have the reheating equipment 23.

[0108] The exit looper 12 is a facility for temporarily storing the metal strip 1 in order to adjust the transport speed of the metal strip 1 in the furnace equipment 21 and the processing speed in the exit equipment 24. The inspection table 14 inspects the dimensional accuracy and surface quality of the metal strip 1. The tension reel 15 is a facility for winding the metal strip 1 into a coil. After being wound into a coil by the tension reel 15, the metal strip 1 that passes the quality inspection on the inspection table may be shipped as a product coil or sent to a surface treatment facility where the metal strip 1 is plated for surface treatment. On the other hand, if the metal strip 1 fails or is held in place after the quality inspection on the inspection table, it may be sent to a recoil line where the dimensions and weight of the metal strip 1 may be adjusted, samples may be taken for quality assurance, shape and dimension inspections may be performed, and the coil may be rewound.

[0109] The temper rolling equipment 30 is disposed between the delivery looper 12 and the inspection table 14. The work rolls 32a, 32b used in the temper rolling mill 31 of the temper rolling equipment 30 need to be replaced at a predetermined timing. By disposing the temper rolling mill 31 downstream of the delivery looper 12, the delivery looper 12 can suppress a change in the speed of the metal strip 1 in the furnace body equipment 21 when the work rolls 32a, 32b are replaced.

[0110] In the continuous annealing line 100, the inlet warpage measuring device 40 may be disposed at any position downstream of the furnace line 21 and upstream of the temper rolling mill 31. This is because no equipment that significantly changes the warpage of the metal strip 1 is provided downstream of the furnace line 21. In the example shown in FIG. 15 , the inlet warpage measuring device 40 is provided downstream of the final cooling zone 11.

[0111] Furthermore, when the delivery warpage measuring device 41 is provided downstream of the temper rolling mill 31, it is preferable that the delivery warpage measuring device 41 be provided near the inspection table 14. Since the delivery warpage shape of the metal strip 1 is sometimes an inspection item for product quality, providing the device near the inspection table 14 makes it easy to correlate with other quality inspections. In this case, the transport distance of the metal strip 1 from the temper rolling mill 31 to the inspection table 14 is usually 20 to 100 m, and the transport time from the temper rolling mill 31 to the inspection table 14 is about 2 to 120 seconds.

[0112] The temper rolling mill 31 is preferably disposed downstream of the heating zone 6, which continuously heats the metal strip 1, and the cooling zone 8, which cools the metal strip 1 heated in the heating zone 6. Heating in the heating zone 6 and cooling in the cooling zone 8 cause warping of the metal strip 1 in the sheet width direction. Therefore, by disposing the temper rolling mill 31 downstream of the heating zone 6 and the cooling zone 8, the height of warping in the sheet width direction of the metal strip 1, which occurs due to cooling in the cooling zone 8, can be reduced.

[0113] As described above, the metal strip manufacturing equipment in which the method for controlling the warpage shape of a metal strip according to the embodiment can be implemented may be the temper rolling equipment 30, 70, 72 shown in FIGS. 1, 10, and 12, or the continuous annealing equipment 100 shown in FIG. 15. [Example]

[0114] Next, an example will be described in which the delivery warpage shape of a metal strip 1 was controlled using the continuous annealing equipment 100 shown in Fig. 15, in which the temper rolling equipment 30 was replaced with a temper rolling equipment 72. The metal strip 1 used in the example was a high-strength steel plate having a tensile strength TS standard of 1180 MPa, a thickness of 1.6 mm, and a width of 921 mm. The operating conditions of the temper rolling mill 31 were such that the entry-side tension and delivery-side tension applied to the metal strip 1 were set to 70 kN, and the elongation rate was changed within a range of 0.05 to 0.10% by changing the roll gap.

[0115] In the examples, a warpage shape prediction model 99 was generated in advance by the warpage shape prediction model generating unit 96, and the warpage shape of the metal strip 1 was controlled using the warpage shape prediction model 99. The delivery side warpage shape used to generate the warpage shape prediction model 99 was the distribution of warpage heights in the strip width direction measured by the delivery side warpage shape measuring device 41. Specifically, the warpage heights measured at each position obtained by dividing the metal strip 1 into sections at 5 mm pitches in the strip width direction were used. Similarly, the entry side warpage shape, which is an input of the warpage shape prediction model, was the distribution of entry side warpage heights measured at each position obtained by dividing the metal strip 1 into sections at 5 mm pitches in the strip width direction. The operation parameters of the temper rolling mill 31 used as input of the warpage shape prediction model were the elongation rate imparted to the metal strip 1 by the temper rolling mill 31 and the set value of the bender force of the work roll bender.

[0116] The warpage shape prediction model 99 was generated using a neural network technique, using these performance data stored in the database 98. The neural network used had three intermediate layers, each with 256 nodes, and used a sigmoid function as the activation function.

[0117] In the warpage shape control device 80, a target value (target warpage value) of the delivery side warpage shape set in the judgment unit 90 was compared with the delivery side warpage shape predicted by the warpage shape prediction model. The target warpage value was set to 5 mm, which is the maximum value of the warpage height in the sheet width direction of the metal strip 1. If the maximum value of the warpage height of the delivery side warpage shape output by the warpage shape prediction model was 5 mm or less, it was judged as OK, and if it exceeded 5 mm, it was judged as NG. If the judgment unit 90 judged the delivery side warpage shape to be NG, the predicted delivery side warpage shape was output to the approximation curve calculation unit 92.

[0118] The predicted delivery side warpage shape of the metal strip output from the warpage shape prediction model is the warpage height at each position divided at 5 mm intervals in the strip width direction, and the approximation curve calculation unit 92 calculates an approximation curve by approximating this with a quadratic curve. Specifically, the approximation curve calculation unit 92 calculates the approximation curve by approximating the predicted result of the delivery side warpage shape with the following formula.

[0119] H=a1×(xW / 2) 2 +a2···(1) where H is the warpage height (mm), x is the distance from the widthwise edge (mm), W is the width of the metal strip (mm), and coefficients a1 and a2 are parameters for specifying the approximation curve. Coefficients a1 and a2 were calculated using the least squares method from the conditions that minimize the error between the delivery warpage shape predicted by the warpage shape prediction model M and the function of equation (1).

[0120] The operation parameter specifying unit 94 specified operation parameters of the temper rolling mill 31 that can reduce the delivery side warpage shape based on the approximation curve of equation (1) calculated by the approximation curve calculating unit 92. Specifically, when the coefficient a1 of equation (1) is positive, the warpage height is greater in the vicinity of the widthwise ends than in the widthwise center, so the operation parameter specifying unit 94 specified a set value for the bender force of the work roll bender of the temper rolling mill 31 to be smaller than the current set value. On the other hand, when the coefficient a1 of equation (1) is negative, the warpage height is smaller in the vicinity of the widthwise ends than in the widthwise center, so the operation parameter specifying unit 94 specified a set value for the bender force of the work roll bender of the temper rolling mill 31 to be larger than the current set value. The warpage shape control device 80 output the set value for the bender force of the work roll bender specified by the operation parameter specifying unit 94 to the control controller 18. Then, the control controller 18 multiplied the set value of the bender force obtained from the warp shape control device 80 by a gain used in normal proportional-integral control and output the result to the temper rolling mill 31, thereby changing the operating conditions of the temper rolling mill 31.

[0121] The processing of the operational parameter specifying unit 94 was performed at intervals of 5 to 20 m in the longitudinal direction of the metal strip during the temper rolling of the metal strip 1 by the temper rolling mill 31. In this manner, the delivery warpage shape in the longitudinal direction of the metal strip 1 was controlled.

[0122] As a result, for the 20 metal strips 1 produced, the pass rate, in which the exit warpage shape was below the target warpage value over the entire longitudinal length, was 100%, which was a significant improvement in the warpage shape of the metal strip 1 compared to the conventional pass rate of 85% when the embodiment was not applied. [Explanation of symbols]

[0123] 1 metal strip 2 Payoff Reel 3. Welding machine 4 Inlet looper 5 Pre-tropical zone 6 Heating Zone 7. Equal Temperature 8 Cooling Zone 9 Reheating Zone 10 Overaged zone 11 Final cooling zone 12 Exit looper 14 Examination table 15 Tension reel 17 Control computer 18 Control Controller 21 Furnace equipment 22 Annealing equipment 23 Reheating equipment 24 Outlet equipment 30 Temper rolling equipment 31 Temper mill 32a work roll 32b work roll 33a Backup Roll 33b Backup Roll 34 Screw down device 35 Bearing box 36 Inlet bridle roll 37 Inlet tension meter 38 Outlet tension meter 39 Exit bridle roll 40. Inlet warpage measurement device 41 Exit warpage measuring device 42 Load detector 43a Work Roll Chock 43b Work Roll Chock 44 Laser scanning laser rangefinder 50 Warp shape control device 51 Warp shape control device 52 Control section 53 Control Unit 54 Input section 56 Output section 58 Memory section 60 Acquisition Department 62 Approximate curve calculation section 64 Operational parameter specification section 70 Temper rolling equipment 72 Temper rolling equipment 80 Warp shape control device 82 Control Unit 84 Memory section 86 Acquisition Department 88 Warpage shape prediction section 90 Judgment section 92 Approximate curve calculation section 94 Operational Parameter Identification Section 96 Warpage shape prediction model generation unit 98 databases 99 Warpage shape prediction model 100 Continuous annealing equipment

Claims

1. A method for controlling a warpage shape of a metal strip in a manufacturing facility for the metal strip, the method comprising: a temper rolling mill for correcting the shape of a continuously transported metal strip; and an inlet warpage measuring device for measuring an inlet warpage shape of the metal strip on the upstream side of the temper rolling mill; the method comprising: calculating an approximation curve of the inlet-side warpage shape measured by the inlet-side warpage shape measuring device using an approximation method selected from the group consisting of parabolic approximation, arc approximation, and envelope approximation; The method for controlling the warpage shape of a metal strip comprises setting operation parameters of the temper rolling mill that can reduce the warpage height of the delivery side warpage shape based on the calculated approximation curve.

2. A method for controlling a warpage shape of a metal strip in a manufacturing facility for the metal strip, the method comprising: a temper rolling mill for correcting the shape of a continuously transported metal strip; and an outlet warpage shape measuring device for measuring an outlet warpage shape of the metal strip downstream of the temper rolling mill, the method comprising: calculating an approximation curve of the exit warpage shape measured by the exit warpage shape measuring device using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation; and setting operation parameters of the temper rolling mill that can reduce the height of the delivery bow shape based on the calculated approximation curve.

3. A method for controlling a warpage shape of a metal strip in a manufacturing facility for the metal strip, the method comprising: a temper rolling mill for correcting the shape of a continuously transported metal strip; and an inlet warpage measuring device for measuring an inlet warpage shape of the metal strip on the upstream side of the temper rolling mill; the method comprising: predicting the delivery side warpage shape using a warpage shape prediction model that receives input data including the entry side warpage shape measured by the entry side warpage shape measuring device and at least one of operation parameters of the temper rolling mill and outputs the delivery side warpage shape; calculating an approximation curve of the predicted exit warpage shape using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation; The method for controlling the warpage shape of a metal strip comprises setting operation parameters of the temper rolling mill that can reduce the warpage height of the delivery side warpage shape based on the calculated approximation curve.

4. the manufacturing facility is a continuous annealing facility that performs heat treatment on the metal strip, the temper rolling mill is disposed downstream of a heating zone that heats the metal strip and a cooling zone that cools the metal strip heated in the heating zone. The method for controlling the warpage shape of a metal strip according to any one of claims 1 to 3.

5. A method for manufacturing a metal strip, comprising: manufacturing a metal strip having a tensile strength of 980 MPa or more by using the method for controlling the warpage shape of a metal strip according to any one of claims 1 to 3.

6. A method for manufacturing a metal strip, comprising the steps of: manufacturing a metal strip having a tensile strength of 980 MPa or more, using the method for controlling the warpage shape of a metal strip according to claim 4.

7. A metal strip warpage shape control device for controlling an outlet warpage shape, which is a warpage shape of the metal strip downstream of the temper rolling mill, in a metal strip manufacturing facility including a temper rolling mill for correcting the shape of a continuously transported metal strip and an inlet warpage shape measuring device for measuring an inlet warpage shape of the metal strip upstream of the temper rolling mill, comprising: an acquisition unit that acquires the inlet-side warpage shape measured by the inlet-side warpage shape measuring device; an approximation curve calculation unit that calculates an approximation curve of the inlet warpage shape using an approximation method selected from parabolic approximation, circular arc approximation, and envelope approximation; and an operation parameter specifying unit that specifies operation parameters of the temper rolling mill based on the approximation curve so as to reduce the warpage height of the delivery-side warpage shape.

8. A metal strip warpage shape control device for controlling the delivery side warpage shape in a metal strip manufacturing facility including a temper rolling mill for correcting the shape of a continuously transported metal strip and an outlet side warpage shape measuring device for measuring the delivery side warpage shape of the metal strip downstream of the temper rolling mill, comprising: an acquisition unit that acquires the delivery warpage shape measured by the delivery warpage shape measuring device; an approximation curve calculation unit that calculates an approximation curve of the delivery warpage shape using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation; and an operation parameter specifying unit that specifies operation parameters of the temper rolling mill based on the approximation curve so as to reduce the warpage height of the delivery-side warpage shape.

9. A metal strip warpage shape control device for controlling an outlet warpage shape, which is a warpage shape of the metal strip downstream of the temper rolling mill, in a metal strip manufacturing facility including a temper rolling mill for correcting the shape of a continuously transported metal strip and an inlet warpage shape measuring device for measuring an inlet warpage shape of the metal strip upstream of the temper rolling mill, comprising: an acquisition unit for acquiring the inlet warpage shape measured by the inlet warpage shape measuring device; a warpage shape prediction unit that receives input data including the inlet warpage shape measured by the inlet warpage shape measuring device and at least one of operation parameters of the temper rolling mill, and predicts the delivery warpage shape using a warpage shape prediction model that outputs the delivery warpage shape; an approximation curve calculation unit that calculates an approximation curve of the delivery-side warpage shape predicted by the warpage shape prediction unit using an approximation method selected from parabolic approximation, arc approximation, and envelope approximation; and an operation parameter specifying unit that specifies operation parameters of the temper rolling mill that can reduce the warpage height of the delivery-side warpage shape based on the approximation curve calculated by the approximation curve calculating unit.

10. the manufacturing facility is a continuous annealing facility that performs heat treatment on the metal strip, The device for controlling warpage shape of a metal strip according to any one of claims 7 to 9, wherein the temper rolling mill is arranged downstream of a heating zone that heats the metal strip and a cooling zone that cools the metal strip heated in the heating zone.

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