Method for controlling warpage shape of metal strip, method for manufacturing metal strip, and device for controlling warpage shape of metal strip

Abstract

Provided is a method for controlling the warpage shape of a metal strip, with which it is possible to control a warpage shape in which the cross-sectional shape in the width direction is W-shaped or a warpage shape approximated by a high-order function, and to reduce the warpage height of the metal strip on the downstream side of a surface finishing mill. Provided is a method for controlling the warpage shape of a metal strip in a metal strip manufacturing facility including a surface finishing mill (31) that corrects the shape of a continuously conveyed metal strip (1), and a warpage shape measuring device that measures the warpage shape of the metal strip. An output-side warpage shape, which is the warpage shape of a metal strip (1) on the downstream side of a surface finishing mill (31), is controlled by calculating an approximation curve of the warpage shape of the metal strip (1) using an approximation method selected from among parabolic approximation, arc approximation, and envelope approximation, and on the basis of the calculated approximation curve, controlling the output-side warpage shape of the metal strip (1) on the downstream side of the surface finishing mill (31). Operating parameters of the surface finishing mill (31) capable of reducing the warping height of the output-side warping shape are set.

Description

Technical Field

[0001] The present invention relates to a method for controlling the warping shape of a metal strip, a method for manufacturing a metal strip, and a device for controlling the warping shape of a metal strip. Background Art

[0002] In continuous annealing equipment for metal strips, it is important to control heat treatment conditions such as heating and cooling in order to give the metal strips to be treated the desired mechanical properties. In the manufacture of high-strength steel sheets, as a control of heat treatment conditions, tempering treatment is often performed on the metal strips after reheating and cooling in order to increase the cooling rate of the cooled metal strips and improve the stamping formability.

[0003] The continuous annealing equipment used to manufacture high-strength steel sheets is equipped with a heating zone, a soaking zone, and a cooling zone. The cooling methods in the cooling zone include liquid quenching, roller cooling, water-gas mixing (mist) cooling, gas jet cooling, etc., and an appropriate cooling method is appropriately selected to control the material of the metal strip. For example, in the case of manufacturing 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, if the cooling rate of the metal strip is increased, there is a problem that the shape of the metal strip is easily changed due to the influence of the volume expansion caused by the thermal contraction of the metal strip and the phase change of the metal structure.

[0004] In order to flatten the shape of the metal strip, a temper rolling mill arranged on the downstream side of the continuous annealing equipment is used to correct the shape. However, when the yield stress of the metal strip is large, it is sometimes difficult to fully flatten the shape of the metal strip even if a temper rolling mill is used for shape correction.

[0005] Patent Document 1 discloses a method for skin-pass rolling such a high-strength steel sheet by applying a work roll having a surface average roughness of more than 10.0 μm to a skin-pass rolling mill. Patent Document 2 discloses that the shape of a metal strip is measured, and a shape control actuator of a rolling mill is operated based on a deviation between the measured shape and a target shape. In Patent Document 2, the distribution of extension in the plate width direction of the metal strip is estimated based on the distribution of contact load in the plate width direction measured by a contact shape meter having a plurality of load cells embedded in the shape metering roll.

[0006] Patent Document 3 discloses a method in which a shape measuring device for optically measuring the shape of a steel plate is provided between a skin-pass rolling mill and a tension leveler, and the operating conditions of the skin-pass rolling mill and the tension leveler are adjusted so that the shape of the steel plate is flat in appearance. In Patent Document 3, a camera is used to capture light of a periodic pattern projected onto a steel plate, and an image analysis device is used to measure the elongation distribution (elongation difference) of the steel plate in the plate width direction.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2013-176802

[0010] Patent Document 2: Japanese Patent No. 6673285

[0011] Patent Document 3: Japanese Patent Application Publication No. 2018-65190 Summary of the invention

[0012] Problems to be solved by the invention

[0013] The method disclosed in Patent Document 1 is a method for performing skin-pass rolling using work rolls having a specific surface roughness, and does not take into account the shape of the metal strip on the input side of the skin-pass rolling mill. Therefore, when the warping height of the metal strip on the input side of the skin-pass rolling mill becomes high, the warping shape cannot be fully suppressed, and even after skin-pass rolling, the warping height of the metal strip may remain high.

[0014] The method disclosed in Patent Document 2 dynamically controls the shape of the metal strip based on the shape of the metal strip measured at the output side of the skin-pass 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 the extension in the plate width direction of the metal strip, that is, estimates the wave shape of the metal strip. Therefore, it is difficult to control the warping shape in which the cross-sectional shape in the plate width direction that may occur in the high-strength steel plate after rapid cooling becomes a W-shaped warping shape, and further difficult to control the warping shape approximated by a high-order function.

[0015] The shape meter used in the method disclosed in Patent Document 3 also measures the distribution of extension in the plate width direction of the metal strip, that is, estimates the wave shape of the metal strip. Therefore, similarly to the method disclosed in Patent Document 2, it is difficult to control the warping shape in which the cross-sectional shape in the plate width direction that may occur in the high-strength steel plate after rapid cooling becomes a W-shaped warping shape, and further difficult to control the warping shape approximated by a high-order function.

[0016] The present invention is completed to solve the above-mentioned problems, and its purpose is to provide a warping shape control method of a metal strip, a metal strip manufacturing method using the warping shape control method, and a metal strip warping shape control device. In a metal strip manufacturing equipment including a surface rolling mill, the cross-sectional shape in the width direction of the plate can be controlled to become a W-shaped warping shape, a warping shape approximated by a high-order function, and the warping height of the metal strip on the downstream side of the surface rolling mill can be reduced.

[0017] Means for solving problems

[0018] Means for solving the above-mentioned problems are as follows.

[0019] [1] A method for controlling the warping shape of a metal strip, in which, in a metal strip manufacturing device including a surface smooth rolling mill for correcting the shape of a continuously conveyed metal strip and a warping shape measuring device for measuring the warping shape of the metal strip, the warping shape of the metal strip on the downstream side of the surface smooth rolling mill, i.e., the warping shape on the output side, is controlled, wherein an approximate curve of the warping shape of the metal strip is calculated using an approximation method selected from parabola approximation, circular arc approximation, and envelope approximation, and based on the calculated approximate curve, operating parameters of the surface smooth rolling mill are set so as to reduce the warping height of the warping shape on the output side.

[0020] [2] A method for controlling the warping shape of a metal strip according to [1], wherein the warping shape measuring device is an input side warping shape measuring device for measuring the input side warping shape of the metal strip on the upstream side of the surface smooth rolling mill, and the method for controlling the warping shape of the metal strip calculates an approximate curve of the input side warping shape measured by the input side warping shape measuring device.

[0021] [3] According to the warping shape control method of the metal strip described in [1], the warping shape measuring device is an output side warping shape measuring device for measuring the output side warping shape of the metal strip on the downstream side of the surface smooth rolling mill, and the warping shape control method of the metal strip calculates an approximate curve of the output side warping shape measured by the output side warping shape measuring device.

[0022] [4] A method for controlling the warping shape of a metal strip according to [1], wherein the warping shape measuring device is an input side warping shape measuring device that measures the input side warping shape of the metal strip on the upstream side of the surface smooth rolling mill, and the method for controlling the warping shape of the metal strip uses a warping shape prediction model to predict the output side warping shape and calculates an approximate curve of the predicted output side warping shape, and the warping shape prediction model takes as input data including the input side warping shape measured by the input side warping shape measuring device and at least one of the operating parameters of the surface smooth rolling mill, and takes as output the output side warping shape.

[0023] [5] A method for controlling the warping shape of a metal strip according to any one of [1] to [4], wherein the manufacturing equipment is a continuous annealing equipment for performing heat treatment on the metal strip, and the surface finishing mill is arranged on the downstream side of a heating zone for heating the metal strip and a cooling zone for cooling the metal strip after being heated in the heating zone.

[0024] [6] A method for manufacturing a metal strip, wherein the method for controlling the warping shape of a metal strip described in any one of [1] to [5] is used to manufacture a metal strip having a tensile strength of 980 MPa or more.

[0025] [7] A device for controlling the warping shape of a metal strip, which controls the warping shape of the metal strip at the downstream side of the surface smooth rolling mill, i.e., the output side warping shape, in a metal strip manufacturing device including a surface smooth rolling mill for correcting the shape of a continuously conveyed metal strip and a warping shape measuring device for measuring the warping shape of the metal strip, wherein the device for controlling the warping shape of the metal strip comprises: an acquisition unit for acquiring the warping shape measured by the warping shape measuring device; an approximate curve calculation unit for calculating an approximate curve of the warping shape using an approximate method selected from parabola approximation, circular arc approximation, and envelope approximation; and an operating parameter determination unit for determining the operating parameters of the surface smooth rolling mill based on the approximate curve so as to reduce the warping height of the output side warping shape.

[0026] [8] A warping shape control device for a metal strip according to [7], wherein the warping shape measuring device is an input side warping shape measuring device for measuring the input side warping shape of the metal strip on the upstream side of the surface smooth rolling mill, the acquiring unit acquires the input side warping shape measured by the input side warping shape measuring device, and the approximate curve calculating unit calculates an approximate curve of the input side warping shape.

[0027] [9] A warping shape control device for a metal strip according to [7], wherein the warping shape measuring device is an output side warping shape measuring device for measuring the output side warping shape of the metal strip on the downstream side of the surface smooth rolling mill, the acquiring unit acquires the output side warping shape measured by the output side warping shape measuring device, and the approximate curve calculating unit calculates an approximate curve of the output side warping shape.

[0028]

[10] The warping shape control device for a metal strip according to [7], wherein the warping shape control device for the metal strip further comprises a warping shape prediction unit, the warping shape measuring device is an input side warping shape measuring device for measuring the input side warping shape of the metal strip on the upstream side of the surface smooth rolling mill, the acquisition unit acquires the input side warping shape measured by the input side warping shape measuring device, the warping shape prediction unit predicts the output side warping shape using a warping shape prediction model, the warping shape prediction model takes as input data including the input side warping shape and at least one of the operating parameters of the surface smooth rolling mill, and takes as output the output side warping shape, and the approximate curve calculation unit calculates an approximate curve of the predicted output side warping shape.

[0029]

[11] A warping shape control device for a metal strip according to any one of [7] to

[10] , wherein the manufacturing equipment is a continuous annealing device for performing heat treatment on the metal strip, and the surface finishing mill is arranged on the downstream side of a heating zone for heating the metal strip and a cooling zone for cooling the metal strip after being heated in the heating zone.

[0030] Effects of the Invention

[0031] By implementing the warping shape control method of the metal strip of the present invention, the cross-sectional shape in the width direction of the plate can be controlled to be a W-shaped warping shape or a warping shape approximated by a high-order function, thereby reducing the warping height of the metal strip on the downstream side of the skin-pass rolling mill. Furthermore, by using the warping shape control method of the metal strip, it is possible to manufacture a metal strip with a reduced warping height. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] [ Figure 1 ] Figure 1 It is a schematic diagram showing a temper rolling facility as an example of a metal strip manufacturing facility capable of implementing the warpage shape control method of the metal strip according to the first embodiment.

[0033] [ Figure 2 ] Figure 2 It is a schematic diagram of a surface polishing mill.

[0034] [ Figure 3 ] Figure 3 It is a schematic diagram showing an example of the warping shape of the metal strip in the plate width direction.

[0035] [ Figure 4 ] Figure 4 This is a schematic diagram showing a state in which the warping shape of the metal strip 1 is measured using a laser scanning laser range finder.

[0036] [ Figure 5 ] Figure 5 This is a schematic diagram showing a state where a warpage shape is measured using a plurality of laser scanning laser rangefinders.

[0037] [ Figure 6 ] Figure 6 It is a schematic diagram showing a structural example of a warping shape control device.

[0038] [ Figure 7 ] Figure 7 This is a graph showing an approximate curve that approximates the distribution of the warpage height in the sheet width direction of the metal strip.

[0039] [ Figure 8 ] Figure 8This is a schematic diagram showing a state in which warping in the width direction of a metal strip is corrected by temper rolling.

[0040] [ Fig. 9 ] Fig. 9 This is a diagram for explaining a method of setting a setting value of a bending force of a work roll bender of a skin-pass rolling mill.

[0041] [ Fig.10 ] Fig.10 It is a schematic diagram showing a temper rolling facility as an example of a metal strip manufacturing facility capable of implementing the warpage shape control method of the metal strip according to the second embodiment.

[0042] [ Fig.11 ] Fig.11 It is a schematic diagram showing the structure of the warping shape control device.

[0043] [ Fig.12 ] Fig.12 It is a schematic diagram showing a temper rolling facility as an example of a metal strip manufacturing facility capable of implementing the warpage shape control method of the metal strip according to the third embodiment.

[0044] [ Fig.13 ] Fig.13 It is a schematic diagram showing the structure of the warping shape control device.

[0045] [ Fig.14 ] Fig.14 is a diagram showing an example of a machine learning model using a neural network.

[0046] [ Fig.15 ] Fig.15 It is a schematic diagram showing an example of a facility of a continuous annealing facility for producing a cold-rolled steel sheet. DETAILED DESCRIPTION

[0047] Hereinafter, the present invention will be specifically described by way of the embodiment of the present invention. The following embodiment is a preferred example of the present invention, and the present invention is not limited to these embodiments at all.

[0048] The warpage shape control method of the metal strip according to the embodiment of the present invention can be implemented using a metal strip manufacturing equipment including a skin-pass rolling mill for correcting the shape of the continuously conveyed metal strip. The metal strip manufacturing equipment may be a dedicated equipment for skin-pass rolling of the metal strip (skin-pass rolling equipment) or a manufacturing equipment composed of a plurality of devices including a skin-pass rolling mill.

[0049] For example, in a continuous annealing device that performs heat treatment on a metal strip, a surface smooth rolling mill that performs surface smooth rolling on the heat-treated metal strip is configured. Such a continuous annealing device also becomes a manufacturing device for a metal strip that can implement the warping shape control method of the present embodiment. The manufacturing device for a metal strip that can implement the warping shape control method of the present embodiment is mainly a manufacturing device for manufacturing steel strips. The representative dimensions (plate thickness / plate width / length) of the steel strip are plate thickness: 0.4~3.2mm, plate width: 700~1800mm, and length: 600~4000m.

[0050] <First Embodiment>

[0051] Figure 1 1 is a schematic diagram showing a temper rolling facility 30 as an example of a metal strip manufacturing facility capable of implementing the warpage shape control method of the metal strip according to the first embodiment. Figure 1 The temper rolling equipment 30 shown includes a temper rolling mill 31. The temper rolling mill 31 is a device that provides a stretch of about 0.1 to 3.0% to the metal strip 1 to flatten the shape of the metal strip 1.

[0052] Figure 2 31 is a schematic diagram of a temper rolling mill. Figure 2 (a) shows a side view of a skin-pass rolling mill. Figure 2 (b) is a front view of a temper rolling mill. Figure 1 , Figure 2 , the skin-pass rolling equipment 30 including the skin-pass rolling mill 31 is described. The skin-pass rolling equipment 30 includes the skin-pass rolling mill 31, an input-side tension roller 36, an input-side tension meter 37, an output-side tension meter 38, an output-side tension roller 39, an input-side warp shape measuring device 40, a warp shape control device 50, a control computer 17, and a control controller 18.

[0053] The skin-pass rolling mill 31 has a pair of working rolls 32a and 32b that directly contact and press down the metal strip 1 as a rolled material, and support rolls 33a and 33b that support the pair of working rolls 32a and 32b from above and below and suppress the bending of the working rolls 32a and 32b. At least one of the working rolls 32a and 32b and the support rolls 33a and 33b is connected to a driving motor via a coupling and a speed reducer at one end, and the roller is rotated by the driving motor. The support roll 33a is supported by a bearing box (support roll holder) 35 at the end of the shaft. The press-down device 34 adjusts the gap between the working rolls 32a and 32b, that is, the roll gap, by shifting the bearing box 35 up and down. The load detector 42 detects the rolling load of the skin-pass rolling mill 31.

[0054] The work rolls 32a and 32b are supported by bearing boxes (work roll stands) 43a and 43b provided at both ends thereof. A hydraulic device (not shown) is provided to exert a force between the upper work roll stand 43a and the lower work roll stand 43b.

[0055] The hydraulic device applies bending force to the work rolls 32a and 32b by applying force between the upper and lower work roll supports 43a and 43b, thereby applying bending deformation to the work rolls 32a and 32b. The mechanism that applies bending deformation to the work rolls 32a and 32b in this way is called a work roll bender, and the force applied between the upper and lower work roll supports 43a and 43b is called a bending force. The mechanism that applies force in the direction of separating the upper and lower work roll supports 43a and 43b is sometimes called an enhancement bender, and the mechanism that applies force in the direction of approaching the upper and lower work roll supports 43a and 43b is sometimes called a weakening bender. The temper rolling mill 31 may include both an enhancement bender and a weakening bender. In this case, the bending force is expressed by positive and negative, for example, the bending force of the enhancement bender is set to positive, and the bending force of the weakening bender is set to negative, so as to distinguish them.

[0056] An input side tension roller 36, an input side tension meter 37, an output side tension meter 38, and an output side tension roller 39 are arranged before and after the skin-pass rolling mill 31. The input side tension roller 36 and the output side tension roller 39 apply appropriate tension to the metal strip 1. The input side tension meter 37 and the output side tension meter 38 are respectively arranged between the skin-pass rolling mill 31 and the input side tension roller 36 and between the skin-pass rolling mill 31 and the output side tension roller 39. The input side tension meter 37 and the output side tension meter 38 measure the tension of the metal strip 1 on the input side and the output side of the skin-pass rolling mill 31.

[0057] The skin-pass rolling mill 31 rolls the metal strip 1 at a predetermined elongation. The elongation refers to the extension of the metal strip 1 before and after skin-pass rolling, and is defined by the increase rate of the length of the metal strip 1 before and after skin-pass rolling. The elongation is measured by the difference in circumferential speed between the circumferential speed of the input-side tension roller 36 and the circumferential speed of the output-side tension roller 39.

[0058] An input-side warping shape measuring device 40 for measuring the warping shape of the metal strip 1 (hereinafter, this warping shape will be referred to as “input-side warping shape”) is provided on the upstream side of the skin-pass rolling mill 31. The input-side warping shape measuring device 40 may be provided at any position as long as it is on the upstream side of the skin-pass rolling mill 31. However, it is preferred that no equipment that greatly changes the warping shape of the metal strip 1 is provided between the input-side warping shape measuring device 40 and the skin-pass rolling mill 31. For example, an annealing furnace, a cooling device, and a rolling device greatly change the warping shape of the metal strip 1. Therefore, the input-side warping shape measuring device 40 is preferably provided between these devices and the skin-pass rolling mill 31.

[0059] The input-side warping shape measuring device 40 measures the input-side warping shape of the metal strip 1 and obtains information specifying the distribution of the warping height in the plate width direction of the metal strip 1. The input-side warping shape measuring device 40 outputs the information specifying the distribution of the warping height in the plate width direction of the metal strip 1 to the warping shape control device 50.

[0060] When the warp shape control device 50 obtains information for determining the distribution of the warp height in the plate width direction of the metal strip 1 from the input-side warp shape measuring device 40, it calculates an approximate curve of the input-side warp shape using an approximation method selected from parabola approximation, arc approximation, and envelope approximation. Then, based on the calculated approximation curve, the warp shape control device 50 determines the operating parameters of the skin-pass rolling mill 31 that can reduce the warp height of the warp shape of the metal strip 1 on the downstream side of the skin-pass rolling mill 31 (hereinafter, this warp shape is described as "output-side warp shape"). The warp shape control device 50 outputs the determined operating parameters of the skin-pass rolling mill 31 to the control controller 18.

[0061] The control controller 18 is, for example, a dedicated computer for executing sequential control such as a PLC (Programmable Logic Controller). The control controller 18 sets the operating conditions of the skin-pass rolling equipment 30 including the skin-pass rolling mill 31, and obtains sensor information from various sensors provided in the skin-pass rolling equipment 30. The control controller 18 sets the operating conditions of the pressing device 34 of the skin-pass rolling mill 31 so that the elongation of the metal strip 1 after skin-pass rolling coincides with the target elongation. Furthermore, if the control controller 18 obtains the operating parameters of the skin-pass rolling mill 31 from the warp shape control device 50, the operating conditions of the skin-pass rolling mill 31 are set based on the operating parameters.

[0062] The control computer 17 is a general-purpose computer such as a workstation or a personal computer. The control computer 17 determines various operating parameters in the skin-pass rolling equipment 30, collects sensor information from the control controller 18, and obtains and stores various information related to the operating performance of the metal strip 1. In addition, the control computer 17 tracks the welded portion between the preceding metal strip and the succeeding metal strip connected by a welder or the like on the upstream side of the skin-pass rolling equipment 30, and determines the current position of the welded portion.

[0063] Next, the warping shape controlled by the warping shape control method of the metal strip of the present embodiment is described. As the warping shape of the metal strip 1, L warping (warping in the length direction of the metal strip 1) or C warping (warping in the plate width direction of the metal strip 1) is known. Among them, C warping is included in the warping shape controlled by the warping shape control method of the metal strip of the present embodiment, but L warping is not included. This is because L warping is constrained by the line tension when the metal strip 1 is continuously conveyed, and it is difficult to measure L warping online. The C warping controlled by the warping shape control method of the metal strip of the present embodiment includes not only C warping in which the cross-sectional shape of the metal strip 1 in the plate width direction is approximated by a quadratic function or an arc, but also includes warping in which the cross-sectional shape in the plate width direction becomes a W-shape or warping approximated by a higher-order function of cubic or higher.

[0064] The warping of the metal strip 1 in the plate width direction is caused by the inability to maintain the in-plane stress generated in the plate width direction of the metal strip 1 due to the cooling process, etc., and it is displaced out of the plane due to buckling. In contrast, the wave-shaped shape defect is caused by the extension of the length direction of the metal strip 1 distributed in the plate width direction, and thus the in-plane stress generated in the length direction of the metal strip 1 cannot be maintained in the plane, and it is displaced out of the plane due to buckling. The warping shape in the plate width direction and the wave shape are the same in that they are out-of-plane deformations caused by buckling, but there is a difference in whether the direction of the stress that causes the buckling is the plate width direction or the length direction.

[0065] Therefore, in the case of a wavy shape, if tension is applied in the longitudinal direction of the metal strip 1, the difference in extension in the plate width direction (difference in extension in the plate width direction) is absorbed, and the shape defect of the metal strip 1 is latent (changes to a flat shape in appearance). On the other hand, in the case of a warped shape in the plate width direction, even if tension is applied in the longitudinal direction of the metal strip 1, it does not have a significant effect on the stress in the plate width direction. Therefore, even if tension is applied in the longitudinal direction of the metal strip 1, the warped shape of the metal strip 1 in the plate width direction does not change.

[0066] The contact shape meter disclosed in Patent Document 2 applies a large tension (e.g., 100 to 200 MPa) between the surface tempering mill and the tension roller on the output side to make the shape defects of the metal strip latent, and measures the contact load distribution in the plate width direction. That is, this contact shape meter is used to measure the wave shape of the metal strip 1, not to measure the warping shape in the plate width direction. In addition, the displacement of the wave shape in the height direction of the metal strip 1 relative to the length direction of the metal strip 1 changes periodically, while there is a difference in the warping shape in which the periodic displacement relative to the length direction of the metal strip 1 is not observed. The period of the wave shape of the metal strip 1 is mostly a pitch of about 0.5 to 5 m in the length direction of the metal strip.

[0067] Figure 3It is a schematic diagram showing an example of the warping shape of the metal strip 1 in the plate width direction. Figure 3 The warping shape shown is an example of the warping shape measured for a metal strip composed of a high-strength steel plate with a plate thickness of 1.2 mm and a plate width of 1200 mm after a cooling process using water quenching and surface rolling by a temper rolling mill. Figure 3 The warpage heights shown are normalized to the maximum height across the width of the board. Figure 3 As shown in FIG. 1 , when a metal strip composed of a high-strength steel plate is rapidly cooled by water quenching, the warping shape in the plate width direction becomes a warping shape approximated by a high-order function.

[0068] The input-side warpage shape measuring device 40 measures the input-side warpage shape of the metal strip 1 and obtains information for determining the distribution of the warpage height in the plate width direction of the metal strip 1. The information for determining the distribution of the warpage height in the plate width direction of the metal strip 1 is, for example, Figure 3 The input-side warping shape measuring device 40 may approximate the curve representing the distribution of the warping height in the plate width direction using an arbitrary function, and obtain the coefficient of the function that determines the approximation as information for determining the distribution of the warping height in the plate width direction of the metal strip 1. The input-side warping shape measuring device 40 may also average the distribution of the warping height at each position in the plate width direction of the metal strip 1 in a range of about 1 to 5 m in the length direction of the metal strip 1. In this way, by averaging the warping height in a range of about 1 to 5 m in the length direction of the metal strip 1, even if the metal strip 1 includes both a warping shape and a wavy shape, the wavy shape can be removed and the warping shape can be determined.

[0069] The input-side warping shape measuring device 40 that can obtain information on the distribution of the warping height at each position in the plate width direction of the metal strip 1 is, for example, a laser rangefinder. A plurality of laser rangefinders as non-contact rangefinders can be arranged at different positions in the plate width direction of the conveyed metal strip 1, and the laser rangefinders are used to measure the warping height at each position. For example, when a laser rangefinder is used to measure the warping height of a metal strip 1 having a plate width of 800 mm to 1900 mm, the number of laser rangefinders arranged at different positions in the plate width direction is preferably 3 or more and 100 or less. More preferably, it is 10 to 20. If the number of laser rangefinders is less than 3, it is difficult to determine the warping shape in the plate width direction of the metal strip 1, so it is not preferred. In addition, even if the number of laser rangefinders is more than 100, the measurement accuracy of the warping shape will not be improved, and the equipment cost will increase, so it is not preferred.

[0070] Figure 4 Schematic diagram showing the state of measuring the warping shape of the metal strip 1 using a laser scanning laser rangefinder. Figure 4As shown, a laser scanning laser rangefinder 44 may be used as the input-side warpage shape measuring device 40. The laser scanning laser rangefinder measures the distance to each position in the plate width direction of the metal strip 1 by scanning the laser in a fan shape, and calculates the height at each position in the plate width direction based on the measured distance. By using the laser scanning laser rangefinder 44, the warpage height in the plate width direction of the metal strip 1 can be measured by scanning the laser in the plate width direction from above the conveyed metal strip 1.

[0071] Figure 5 Schematic diagram showing the state of measuring the warpage shape using multiple laser scanning laser rangefinders. Figure 5 As shown in FIG. 1 , a plurality of laser scanning laser distance meters 44 may be used as the input-side warpage shape measuring device 40. In this case, a plurality of laser scanning laser distance meters 44 are arranged in the plate width direction of the metal strip 1 to measure the warpage height in the plate width direction of the metal strip 1. Figure 4 The device shown measures the input side warpage shape in a short time.

[0072] In addition, as the input-side warpage shape measuring device 40, a device that measures the input-side warpage shape by a light section method may also be used. In the light section method, a laser beam that expands in a fan shape relative to the plate width direction is irradiated from above the metal strip 1, and reflected light from the metal strip 1 is received, and the received reflected light is photographed by an image sensor, and the photographed image is processed to measure the warpage height of the metal strip 1. Devices that measure the input-side warpage shape by the light section method are, for example, the LJ-X8000 series manufactured by Keyence and the Gocator manufactured by LMT Technologies.

[0073] The input-side warping shape measuring device 40 preferably has a measurement accuracy of 1 mm or less, and more preferably has a measurement accuracy of 0.5 mm or less, for the warping height of the metal strip 1. By using the input-side warping shape measuring device 40 with a measurement accuracy of 1 mm or less, even if the upper limit of the warping height of the metal strip 1 is set to a range of 5 to 10 mm, the warping height of the metal strip 1 can be controlled within the range.

[0074] The measurement of the warpage height of the metal strip 1 by the input-side warpage shape measuring device 40 is preferably capable of being measured at intervals of 1 m or less in the length direction of the metal strip 1. The measurement frequency of the warpage height of the continuously conveyed metal strip 1 is preferably 10 Hz or more, and more preferably 20 Hz or more. For example, in the output-side equipment of the continuous annealing equipment, the metal strip 1 is sometimes conveyed at a speed of 600 m / min or more. Even if the metal strip 1 is conveyed at this conveying speed, the warpage shape can be measured at intervals of 1 m or less in the length direction of the metal strip 1 as long as the measurement frequency of the warpage shape is 10 Hz or more.

[0075] Next, the warp shape control device 50 will be described. Figure 6 : is a schematic diagram showing a configuration example of a warping shape control device 50. The warping shape control device 50 is, for example, a general-purpose computer such as a workstation or a personal computer. The warping shape control device 50 includes 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 by executing a program read from the storage unit 58, the control unit 52 functions as an acquisition unit 60, an approximate curve calculation unit 62, and an operation parameter determination unit 64.

[0076] 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 updateable flash memory, a hard disk built in or connected via a data communication terminal, a memory card, and other information recording media and their read / write devices. The storage unit 58 stores programs for the control unit 52 to execute various functions, data used by the programs, etc.

[0077] Next, the processing performed by the acquisition unit 60, the approximate curve calculation unit 62, and the operation parameter determination unit 64 is described. The acquisition unit 60 acquires the distribution of the warpage height in the plate width direction of the metal strip 1 as the information of the input-side warpage shape of the metal strip 1 from the input-side warpage shape measurement device 40. The acquisition unit 60 outputs the acquired information to the approximate curve calculation unit 62.

[0078] When acquiring information for determining the distribution of the warpage height in the plate width direction of the metal strip 1 , the approximate curve calculation unit 62 approximates the distribution of the warpage height in the plate width direction of the metal strip 1 using an approximation method selected from parabola approximation, arc approximation, and envelope approximation.

[0079] By using parabola approximation, arc approximation, or envelope approximation, the approximate curve calculation unit 62 can approximate the distribution of the warpage height in the plate width direction of the metal strip 1 to a monotonic curve having one inflection point with respect to the position in the plate width direction of the metal strip 1. Thus, an approximate curve is obtained that represents the overall tendency of the warpage shape in the plate width direction of the metal strip 1. The approximate curve does not need to be bilaterally symmetrical with respect to the position in the center of the plate width direction of the metal strip 1, but is preferably a monotonic curve having an inflection point at the center of the plate width direction of the metal strip 1.

[0080] Figure 7 : is a graph showing an approximate curve that approximates the distribution of the warpage height in the plate width direction of the metal strip 1. Figure 7 In (a) to (c), the distribution of the warpage height of the metal strip 1 in the plate width direction is indicated by a solid line, and the approximate curve approximating the distribution is indicated by a dotted line. Figure 7 In order to make the description of the approximate curve easier to understand, the plate width position on the horizontal axis compresses the actual size in the horizontal direction, and the warp height on the vertical axis magnifies the actual size in the vertical direction. Figure 7 The warping height distribution in the actual plate width direction of the metal strip 1 is not shown, but the warping height is exaggerated to show a distribution of warping heights larger than the actual warping heights.

[0081] Figure 7 (a) is a graph showing an approximate curve obtained by approximating the distribution of the warpage height in the plate width direction of the metal strip 1 by parabola (quadratic curve) approximation. Parabola approximation is an approximation method for approximating the distribution of the warpage height by a quadratic curve with respect to a coordinate system composed of the position in the plate width direction of the metal strip 1 and the warpage height. The approximate curve based on parabola approximation can be obtained by applying a known method such as the least squares method.

[0082] Figure 7 (b) is a graph showing an approximate curve obtained by performing arc approximation on the distribution of the warpage height in the plate width direction of the metal strip 1. Arc approximation is an approximation method of approximating the distribution of the warpage height by an arc with respect to a coordinate system composed of the position in the plate width direction of the metal strip 1 and the warpage height. The approximate curve based on the arc approximation can also be obtained by applying a known method such as the least squares method.

[0083] Figure 7(c) is a graph showing an approximate curve obtained by performing envelope approximation on the distribution of the warpage height in the plate width direction of the metal strip 1. An envelope generally refers to a curve that is tangent to all of the curve families. The warpage shape controlled by the warpage shape control method of the metal strip of the present embodiment includes a plurality of curves that can approximate the distribution of the warpage height of the metal strip 1 by a high-order function, so the envelope becomes a curve that is tangent to all of these plurality of curves. Specifically, a curve that is connected to all of the peaks representing the warpage height in the plate width direction of the metal strip 1 becomes an envelope approximation curve.

[0084] like Figure 7 As shown in (a) to (c) of FIG. 1 , no matter which approximation method is used among parabola approximation, arc approximation, and envelope approximation, the approximate approximation curve is a monotonous curve indicating the overall tendency of the warping shape in the plate width direction of the metal strip 1. Therefore, even when the distribution of the warping height in the plate width direction of the metal strip 1 is a high-order curve of three or more such as a W-shaped curve, by calculating the approximate curve, it is possible to easily distinguish between the region where the warping height of the metal strip 1 is high and the region where the warping height is low. That is, when the approximate curve is a downward convex shape, it indicates that the warping height at the plate width end portion is relatively high relative to the plate width center portion, and when the approximate curve is an upward convex shape, it indicates that the warping height at the plate width end portion is relatively low relative to the plate width center portion. By calculating the approximate curve in this way, it is possible to easily determine the overall tendency of the warping shape, and therefore, by using the approximate curve, it is possible to easily determine the operating parameters of the skin-pass rolling mill 31 that can reduce the warping shape of the metal strip 1 on the outlet side of the skin-pass rolling mill 31.

[0085] Refer again Figure 6 When the approximate curve is calculated by the above method, the approximate curve calculation unit 62 outputs the approximate curve to the operating parameter determination unit 64. The operating parameter determination unit 64 determines the operating parameters of the skin-pass rolling mill 31 that can reduce the warpage height of the output-side warpage shape. The operating parameters of the skin-pass rolling mill 31 are set values ​​of the operating conditions that affect the warpage shape of the metal strip 1 among the operating conditions of the skin-pass rolling mill 31.

[0086] The operation parameter determination unit 64 determines, for example, a setting value of a bending force of a work roll bender, which is a shape control actuator of the skin-pass rolling mill 31, as an operation parameter of the skin-pass rolling mill 31. The work roll bender is a shape control actuator that applies a bending force to the work rolls 32a and 32b to adjust the deflection of the work rolls 32a and 32b. By adjusting the deflection of the work rolls 32a and 32b using the work roll bender, a distribution of rolling loads is formed in the plate width direction of the metal strip 1 by the work rolls 32a and 32b. By skin-pass rolling the metal strip 1 using the work rolls 32a and 32b with the distribution of rolling loads, the wave shape of the metal strip 1 after skin-pass rolling is corrected.

[0087] The present inventors have found that, similar to the corrugated shape, the warping shape in the plate width direction of the metal strip 1 can be corrected by temper rolling the metal strip 1 using the work rolls 32a and 32b with a rolling load distribution. Specifically, the inventors have found that the warping height in the plate width direction of the metal strip 1 can be reduced by adjusting the bending force of the work roll bender so that the rolling load at the position where the warping height in the plate width direction of the metal strip 1 is large becomes large.

[0088] Figure 8 Schematic diagram showing the state in which the warping of the metal strip 1 in the plate width direction is corrected by skin pass rolling. Figure 8 In FIG. 1 , in order to explain the effect of the work roll bender, the warping height of the metal strip 1 in the plate width direction is also shown to be larger than the actual warping height. Figure 8 (a) is a schematic diagram showing the state of a metal strip 1 having a warp with a substantially uniform amplitude in the strip width direction before being subjected to skin pass rolling. When a specific bending force is set and the work roll 32a is deflected, the distribution of the unit width load (rolling load applied per unit width of the metal strip 1) generated on the work roll 32a along the strip width direction of the metal strip 1 is shown. For example, Figure 8 In the work roll 32 a shown in (a), the load per unit width is smaller near the strip width end portions than in the strip width center portion of the metal strip 1 .

[0089] Figure 8 (b) is a schematic diagram showing a state after skin-pass rolling of a metal strip 1 having a warp with a substantially uniform amplitude in the strip width direction. If the metal strip 1 is skin-pass rolled using work rolls that generate such a distribution of unit width load, Figure 8 As shown in (b), although the warping height can be reduced in the central part of the plate width where the unit width load is large, the warping height cannot be reduced near the plate width ends where the unit width load is small. This is considered to be because, in the roll gap, the bending portion in the plate width direction is constrained by the work rolls, and bending stress is generated inside the metal strip 1 to flatten the bending in the plate width direction, but the bending stress generated inside is affected by the unit width load, and the bending stress near the plate width ends is relatively reduced, so that the warping height near the plate width ends does not become lower.

[0090] Fig. 9 It is a diagram for explaining a method of setting a setting value of the bending force of the work roll bender of the skin temper rolling mill 31. Fig. 9 (a) is a schematic diagram showing the distribution of the warpage height in the plate width direction of the metal strip 1 obtained from the input-side warpage shape measuring device 40 . Fig. 9 (b) is a diagram showing an envelope approximate curve of the input-side warping shape calculated by the approximate curve calculation unit 62 .

[0091] The approximate curve calculation unit 62 calculates Fig. 9 The high-order curve shown in (a) shows that the warping shape in the width direction of the plate is converted into Fig. 9 The gentle approximate curve shown in (b) is shown in Fig. Fig. 9 In the warping shape in the plate width direction shown in (a), as a whole, the warping height near the plate width end portions is higher than the warping height in the plate width center portion.

[0092] The operating parameter determination unit 64 determines the setting value of the bending force of the work roll bender based on the approximate curve calculated by the approximate curve calculation unit 62. Specifically, the setting value of the bending force of the work roll bender is determined so that the rolling load of the work roll becomes larger near the width end portion where the warp height is high and the rolling load of the work roll becomes smaller in the width center portion where the warp height is low. In this way, the operating parameter determination unit 64 determines the setting value of the bending force of the work roll bender in accordance with the overall tendency of the warp shape determined by the approximate curve.

[0093] Fig. 9 (c) is a schematic diagram showing the warping shape in the plate width direction of the metal strip 1 after the skin temper rolling by the skin temper rolling mill after the setting value of the bending force set by the operation parameter determination unit 64 is reflected. Fig. 9 As shown in (c), by performing surface smooth rolling on the metal strip 1 using a surface smooth rolling mill 31 having a set value that reflects the bending force of the working roll, surface smooth rolling can be performed with a rolling load corresponding to the warping height in the plate width direction of the metal strip 1, and the warping height near the two end portions where the warping height is high can be significantly reduced.

[0094] However, the operating parameters determined by the operating parameter determination unit 64 are not limited to the bending force of the work roll bender, and the operating parameters of other shape control actuators that can control the flexural deformation of the work rolls and the distribution of the roll gap in the sheet width direction may be determined. For example, the operating parameters of the shape control actuator that can change the sheet width direction distribution of the roll gap in the sheet width direction of the metal strip 1 in a gentle curve shape, such as the hydraulic pressure of the variable crown roll that can adjust the roll crown by hydraulic pressure, the roll displacement amount that displaces the work roll or the intermediate roll in the axial direction, and the pressing force of each segment of the split backup roll, may be determined.

[0095] The operating parameter determination unit 64 outputs the determined operating parameters to the control controller 18. The control controller 18 sets the acquired operating parameters as operating conditions of the skin-pass rolling mill 31. In this way, the operating parameters determined by the operating parameter determination unit 64 are set in the skin-pass rolling mill 31. And, by skin-pass rolling the metal strip 1 using the skin-pass rolling mill 31 in which the parameters are set as operating conditions, the warping shape of the metal strip 1 in the plate width direction can be controlled, and the production of the metal strip 1 with the warping height in the plate width direction reduced on the downstream side of the skin-pass rolling mill 31 can be realized.

[0096] The warping shape control method of the metal strip of the first embodiment performs feedforward control using the input-side warping shape. By performing feedforward control, the warping height of the output-side warping shape of the metal strip 1 can be quickly controlled to be low.

[0097] The input-side warping shape of the metal strip 1 changes due to the temper rolling performed by the temper rolling mill 31. However, when the elongation given to the metal strip 1 by the temper rolling mill 31 is small, the warping 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 warping tendency of the input-side warping shape of the metal strip 1 does not change, so the operating parameters of the temper rolling mill 31 that can reduce the warping height of the output-side warping shape can be determined based on the approximate curve of the input-side warping shape.

[0098] On the other hand, when the elongation rate given to the metal strip 1 by the skin-pass rolling mill 31 is large, the overall warping tendency of the warping shape of the metal strip 1 may change before and after skin-pass rolling. Therefore, even if the operation parameters are determined based on the approximate curve of the input-side warping shape, and skin-pass rolling is performed using the skin-pass rolling mill 31 reflecting the operation parameters, the overall warping tendency of the warping shape of the metal strip 1 changes, and the warping shape may increase instead. Therefore, the first embodiment in which the operation parameters of the skin-pass rolling mill are set based on the input-side warping shape is not preferably applied to the case where the elongation rate given to the metal strip 1 by the skin-pass rolling mill 31 is large. The first embodiment is preferably applied to the case where the elongation rate given to the metal strip 1 by the skin-pass rolling mill 31 is 0.3% or less.

[0099] In addition, the control controller 18 is preferably capable of setting the operating parameters of the skin-pass rolling mill 31 during the manufacture of the metal strip 1. Specifically, it is preferred that during the manufacture of the metal strip 1, the warp shape of the metal strip 1 is measured at any time by the input-side warp shape measuring device 40, the approximate curve of the input-side warp shape is calculated by the warp shape control device 50, and the set value of the operating parameter of the skin-pass rolling equipment 30 that can reduce the warp height of the output-side warp shape is output to the control controller 18, so that it can be set and updated at any time. In this case, the control controller 18 calculates the time when the position of the warp shape measured by the input-side warp shape measuring device 40 reaches the skin-pass rolling mill 31 using the tracking information of the welded portion generated by the control computer 17 and the conveying speed of the metal strip 1. Then, at the time when the position of the warp shape measured by the input-side warp shape measuring device 40 reaches the skin-pass rolling mill 31, the control controller 18 changes the manufacturing conditions to the operating parameters of the skin-pass rolling equipment 30 set by the operating parameter determination unit 55. As a result, the warp height of the output-side warp of the metal strip 1 can be reduced in the longitudinal direction of the metal strip 1.

[0100] <Second Embodiment>

[0101] Fig.10 Schematic diagram showing a temper rolling facility 70 as an example of a metal strip manufacturing facility capable of implementing the warpage shape control method of the metal strip according to the second embodiment. Fig.10 In the surface temper rolling equipment 70 shown in FIG. Figure 1 The same components as those of the skin-pass rolling equipment 30 are denoted by the same reference numerals, and their description is omitted. Figure 1 The illustrated skin-pass rolling equipment 30 is different in that it has an output-side warp shape measuring device 41 instead of the input-side warp shape measuring device 40 , and has a warp shape controlling device 51 instead of the warp shape controlling device 50 .

[0102] An output-side warping shape measuring device 41 for measuring the output-side warping shape of the metal strip 1 is provided on the downstream side of the skin-pass rolling mill 31. The output-side warping shape measuring device 41 measures the output-side warping shape of the metal strip 1 and obtains information for determining the distribution of the warping height in the plate width direction of the metal strip 1. The output-side warping shape measuring device 41 may be the same as the input-side warping shape measuring device 40, for example, a laser rangefinder, a laser scanning laser rangefinder, or a warping shape measuring device using a light cutting method. The output-side warping shape measuring device 41 outputs the information for determining the distribution of the warping height in the plate width direction of the metal strip 1 to the warping shape control device 51.

[0103] The warp shape control device 51 calculates an approximate curve of the warp shape on the delivery side when acquiring information for determining the distribution of the warp height in the plate width direction of the metal strip 1 from the delivery side warp shape measuring device 41. The warp shape control device 51 determines the operating parameters of the skin-pass rolling mill 31 that can reduce the warp height of the delivery side warp shape based on the calculated approximate curve. The warp shape control device 51 outputs the determined operating parameters of the skin-pass rolling mill 31 to the control controller 18.

[0104] Fig.11 Schematic diagram showing the structure of the warping shape control device 51. Fig.11 In the warping shape control device 51 shown in FIG. Figure 6 The same components of the warping shape control device 50 are denoted by the same reference numerals, and description thereof will be omitted.

[0105] The warping shape control device 51 is also a general-purpose computer such as a workstation or a personal computer. The warping shape control device 51 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 by executing a program read from the storage unit 58, the control unit 53 functions as an acquisition unit 61, an approximate curve calculation unit 62, and an operation parameter determination unit 64.

[0106] Next, the processing performed by the acquisition unit 61 is described. The acquisition unit 61 acquires information that specifies the distribution of the warpage height in the plate width direction of the metal strip 1 as the output-side warpage shape of the metal strip 1 from the output-side warpage shape measurement device 41. The acquisition unit 61 outputs the acquired information to the approximate curve calculation unit 62. The processing performed by the approximate curve calculation unit 62 and the operation parameter determination unit 64 is the same as that of the first embodiment.

[0107] The operating parameter determination unit 64 outputs the determined operating parameters to the control controller 18. The control controller 18 sets the acquired operating parameters as operating conditions of the skin-pass rolling mill 31. In this way, the operating parameters determined by the operating parameter determination unit 64 are set in the skin-pass rolling mill 31. And, by skin-pass rolling the metal strip 1 using the skin-pass rolling mill 31 with the set parameters, the warping shape in the plate width direction can be controlled, and the production of the metal strip 1 with the warping height in the plate width direction reduced on the downstream side of the skin-pass rolling mill 31 can be realized.

[0108] The warping shape control method of the metal strip of the second embodiment performs feedback control using the output side warping shape. Feedback control generates dead time from measuring the warping shape of the metal strip 1 to setting the operating conditions of the skin-pass rolling mill 31. Therefore, the responsiveness of the warping shape control method of the metal strip of the second embodiment is inferior to that of the first embodiment. On the other hand, in the feedback control, the output side warping shape measuring device 41 is used to measure the output side warping shape as the control object, so the warping shape control method of the metal strip of the second embodiment can be applied to the manufacturing equipment of the metal strip 1 including the skin-pass rolling mill 31 regardless of the elongation given to the metal strip 1 by the skin-pass rolling mill 31.

[0109] <Third Embodiment>

[0110] Fig.12 FIG. 7 is a schematic diagram showing a temper rolling facility 72 as an example of a metal strip manufacturing facility capable of implementing the warpage shape control method of the metal strip according to the third embodiment. Fig.12 In the surface polishing equipment 72 shown, Figure 1 The surface polishing equipment 30 shown or Fig.10 In the illustrated skin-pass rolling equipment 70, the same structures are denoted by the same reference numerals, and description thereof will be omitted.

[0111] Fig.12 The surface polishing equipment 72 shown is Figure 1 The surface temper rolling equipment 30 shown in the figure is different in that it has an output-side warp shape measuring device 41 and a warp shape control device 80 instead of the warp shape control device 50. Fig.10 The output-side warpage shape measuring device 41 of the skin temper rolling equipment 70 shown is the same.

[0112] An input-side warping shape measuring device 40 for measuring the input-side warping shape of the metal strip 1 is provided on the upstream side of the skin-pass rolling mill 31, and an output-side warping shape measuring device 41 for measuring the output-side warping shape of the metal strip 1 is provided on the downstream side of the skin-pass rolling mill 31. The input-side warping shape measuring device 40 measures the input-side warping shape of the metal strip 1 and obtains information for determining the distribution of the warping height in the plate width direction of the metal strip 1. The input-side warping shape measuring device 40 outputs the obtained information for determining the distribution of the warping height in the plate width direction of the metal strip 1 to the warping shape control device 80 and the control controller 18.

[0113] The output-side warping shape measuring device 41 measures the output-side warping shape of the metal strip 1, and obtains information for determining the distribution of the warping height in the plate width direction of the metal strip 1. The output-side warping shape measuring device 41 outputs the information for determining the distribution of the warping height in the plate width direction of the metal strip 1 to the control controller 18. The control computer 17 obtains the sensor information including the input-side warping shape and the output-side warping shape obtained by the control controller 18 as information related to the operation performance of the metal strip 1, and stores it.

[0114] The warp shape control device 80 obtains information for determining the distribution of the warp height in the plate width direction of the metal strip 1 from the input-side warp shape measuring device 40. In addition, the warp shape control device 80 obtains at least one of the operating parameters of the skin-pass rolling mill 31 from the control computer 17 via the control controller 18. The operating parameter of the skin-pass rolling mill 31 is a set value of the operating condition that affects the warp shape of the metal strip 1 among the operating conditions of the skin-pass rolling mill 31. The warp shape control device 80 predicts the output-side warp shape using a warp shape prediction model that takes as input input data including at least one of the input-side warp shape and the operating parameter and takes as output the output-side warp shape.

[0115] The warp shape control device 80 calculates an approximate curve of the predicted output-side warp shape. The warp shape control device 80 determines the operating parameters of the skin-pass mill 31 that can reduce the warp height of the output-side warp shape based on the calculated approximate curve. The warp shape control device 80 outputs the set operating parameters of the skin-pass mill 31 to the control controller 18.

[0116] Fig.13 FIG. 8 is a schematic diagram showing the structure of the warping shape control device 80. In the warping shape control device 80, Figure 6 The same components of the warping shape control device 50 are denoted by the same reference numerals, and description thereof will be omitted.

[0117] The warping shape control device 80 is also a general-purpose computer such as a workstation or a personal computer. The warping shape control device 80 includes a control unit 82, an input unit 54, an output unit 56, and a storage unit 84. The control unit 82 is, for example, a CPU, and by executing a program read from the storage unit 84, the control unit 82 functions as an acquisition unit 86, a warping shape prediction unit 88, a determination unit 90, an approximate curve calculation unit 92, an operation parameter determination unit 94, and a warping shape prediction model generation unit 96. The storage unit 84 is, for example, an information recording medium such as a flash memory that can update records, a hard disk built in or connected via a data communication terminal, a memory card, and a read / write device thereof. The storage unit 84 stores programs for the control unit 82 to execute various functions, data used by the programs, and the like.

[0118] The storage unit 84 also stores a database 98 and a warp shape prediction model 99. The database 98 stores a data set of at least one of the measured values ​​of the input-side warp shape, the measured values ​​of the output-side warp shape, and the operation parameters of the metal strip 1 manufactured by the skin-pass rolling equipment 72 in the past. These measured values ​​and operation parameters are collected and stored in the control computer 17, and are obtained from the control computer 17 via the control controller 18. The warp shape prediction model 99 is prepared in advance by the warp shape prediction model generation unit 96 and stored in the storage unit 84.

[0119] The warping shape prediction model 99 is, for example, a machine learning model that has been learned and takes as input data including at least one of an input-side warping shape and an operating parameter, and takes as output an output-side warping shape. In the case where the input-side warping shape is information for determining the distribution of the warping height in the plate width direction of the metal strip 1, the input data input to the learning model includes at least one of the values ​​of the warping height at each position in the plate width direction and the operating parameter. In addition, in the case where the input-side warping shape is a function obtained by approximating the distribution of the warping height in the plate width direction of the metal strip 1, the input data input to the learning model includes at least one of the coefficients for determining the function and the operating parameter.

[0120] In addition, when information that determines the distribution of the warpage height in the plate width direction of the metal strip 1 is output as the output-side warpage shape, a warpage shape prediction model that outputs the warpage height at each position in the plate width direction is prepared in advance. In addition, when a function that approximates the warpage height in the plate width direction of the metal strip 1 is output as the output-side warpage shape, a shape prediction model that outputs each coefficient that determines the function is prepared in advance.

[0121] Next, the processing performed by the acquisition unit 86, the warp shape prediction unit 88, the determination unit 90, the approximate curve calculation unit 92, the operation parameter determination unit 94, and the warp shape prediction model generation unit 96 will be described. The acquisition unit 86 acquires information on the distribution of the warp height in the plate width direction for determining the input side warp shape from the input side warp shape measurement device 40 as the input side warp shape of the metal strip 1. In addition, the acquisition unit 86 acquires at least one of the operation parameters of the skin temper rolling mill 31 from the control computer 17 via the control controller 18. The acquisition unit 86 outputs at least one of the input side warp shape and the operation parameter to the warp shape prediction unit 88.

[0122] When the warping shape prediction unit 88 obtains at least one of the input-side warping shape and the operation parameter, it reads out the warping shape prediction model from the storage unit 84, inputs at least one of the input-side warping shape and the operation parameter into the warping shape prediction model, and outputs the output-side warping shape. In this way, the warping shape prediction unit 88 predicts the output-side warping shape.

[0123] The warping shape prediction unit 88 outputs the predicted output-side warping shape to the determination unit 90. The determination unit 90 determines whether the predicted output-side warping shape is less than a preset reference value (target value of warping). The reference value may be obtained from the control computer 17 via the acquisition unit 86 and the control controller 18, or the reference value may be stored in advance in the storage unit 84 and read from the storage unit 84. When it is determined that the output-side warping shape predicted by the warping shape prediction unit 88 exceeds the reference value, the determination unit 90 outputs the predicted output-side warping shape to the approximate curve calculation unit 92.

[0124] On the other hand, when it is determined that the output-side warping shape predicted by the warping shape prediction unit 88 does not exceed the reference value, the determination unit 90 discards the predicted output-side warping shape without outputting it to the approximate curve calculation unit 92. In this way, the determination unit 90 discards the output-side warping shape, and the current operating condition of the skin temper rolling mill 31 is maintained.

[0125] When the approximate curve calculation unit 92 obtains the predicted output-side warping shape from the determination unit 90, it calculates an approximate curve that approximates the predicted output-side warping shape using parabola approximation, arc approximation, or envelope approximation. The approximate curve calculation unit 92 outputs the calculated approximate curve to the operation parameter determination unit 94. The operation parameter determination unit 94 determines the operation parameters of the skin-pass rolling mill 31 that can reduce the warping height of the predicted output-side warping shape. The method of calculating the approximate curve by the approximate curve calculation unit 92 and the method of determining the operation parameters of the skin-pass rolling mill 31 by the operation parameter determination unit 94 are the same as those of the first embodiment.

[0126] The operating parameter determination unit 94 outputs the determined operating parameters to the control controller 18. The control controller 18 changes the operating conditions of the skin-pass rolling mill 31 using the acquired operating parameters. In this way, the operating parameters determined by the operating parameter determination unit 94 are reflected in the operating conditions of the skin-pass rolling mill 31. Furthermore, by skin-pass rolling the metal strip 1 using the skin-pass rolling mill 31, the warping shape of the metal strip 1 in the plate width direction can be controlled, and the production of the metal strip with the warping height in the plate width direction reduced on the downstream side of the skin-pass rolling mill 31 can be realized.

[0127] In the warp shape control method of the metal strip of the third embodiment, the warp shape of the output side as the control object is predicted using the input side warp shape, and the set value of the operating parameter of the skin-pass rolling mill 31 that can reduce the warp height of the output side warp shape is determined. Therefore, the warp shape control method of the metal strip of the third embodiment can be applied to the manufacturing equipment of the metal strip 1 including the skin-pass rolling mill 31 regardless of the elongation given by the skin-pass rolling mill 31. In addition, since the set value of the operating parameter of the skin-pass rolling mill 31 is determined at the time of obtaining at least one of the input side warp shape and the operating parameter of the skin-pass rolling mill 31, there is no waste time generated as in the second embodiment. Therefore, the region of the metal strip 1 that becomes inappropriate due to the uncontrolled output side warp shape is shorter than in the second embodiment.

[0128] In addition, in the third embodiment, an example is shown in which the warp shape control device 80 includes the determination unit 90, but the warp shape control device 80 may not include the determination unit 90. In this case, the warp shape prediction unit 88 outputs the predicted output-side warp shape to the approximate curve calculation unit 92. The approximate curve calculation unit 92 calculates the approximate curve of the output-side warp shape, and the operation parameter determination unit 94 determines the operation parameter that can reduce the warp height based on the calculated approximate curve. By changing the operation condition of the skin-pass rolling mill 31 using the determined operation parameter, it is possible to manufacture a metal strip whose warp height in the plate width direction is reduced on the downstream side of the skin-pass rolling mill 31. In this way, even in the case where the determination unit 90 is not provided, it is possible to manufacture a metal strip whose warp height in the plate width direction is reduced on the downstream side of the skin-pass rolling mill 31, similarly to the case where the determination unit 90 is provided.

[0129] Next, the method for generating the warp shape prediction model by the warp shape prediction model generating unit 96 will be described. In the present embodiment, the actual data of the warp shape of the input side and the warp shape of the output side are acquired by using the input side warp shape measuring device 40 for measuring the warp shape of the input side on the upstream side of the skin-pass rolling mill 31 and the warp shape of the output side measuring device 41 for measuring the warp shape of the output side on the downstream side of the skin-pass rolling mill 31. Since the control computer 17 generates the tracking information of the welded portion of the metal strip 1, the control computer 17 acquires the warp shape of the input side and the warp shape of the output side in correspondence with the distance from the front end welded portion of the metal strip 1 and stores them by using the information related to the conveying speed of the metal strip 1 and the tracking information. At this time, the metal strip 1 is extended in the skin-pass rolling mill 31, so it is preferable to correct the position from the front end welded portion measured by the warp shape measuring device 41 on the output side according to the elongation of the skin-pass rolling mill 31. Then, the control computer 17 obtains and stores the operating parameters of the skin temper mill 31 in correspondence with the distance from the front end weld portion of the metal strip 1 .

[0130] The acquisition unit 86 acquires a data set from the control computer 17 via the control controller 18, the data set including the measured values ​​of the input-side warpage shape and the output-side warpage shape at the position where the distance from the front end weld portion of the metal strip 1 is the same, and at least one of the operating parameters of the skin-pass rolling mill 31 when the position passes through the skin-pass rolling mill 31. The acquisition unit 86 stores the acquired data set in the database 98 of the storage unit 84. It is preferable to store 200 or more data sets in the database 98, and it is more preferable to store 1000 or more data sets in the database 98.

[0131] In addition, the acquisition unit 86 preferably acquires the above data groups from the front end (e.g., within 20 m from the front end welding part), the stable part, and the tail end (e.g., within 20 m from the tail end welding part) of the metal strip 1. In metal products, it is usually determined whether the product can be shipped by inspecting the front end, the stable part, and the tail end. Therefore, in order to cope with the inspection, it is preferred to acquire the data groups of the front end, the stable part, and the tail end.

[0132] Furthermore, the acquisition unit 86 preferably acquires a data set of the entire length of the metal strip 1 at a predetermined interval from the front end to the rear end of the metal strip 1. The interval for acquiring the data set is preferably set within a range of 5 m to 20 m. By storing the data set covering the entire length of the metal strip 1 in the database 98 and using the data set to create a warping shape prediction model, the output side warping shape can be predicted with high accuracy. In addition, the acquisition unit 86 may set a certain number of data sets as an upper limit and appropriately update the data set stored in the database 98 within the upper limit.

[0133] The warping shape prediction model generation unit 96 uses the data set stored in the database 98 to generate a warping shape prediction model that uses input data including at least one of the input-side warping shape and the operation parameter as input and outputs the output-side warping shape as output. In the case where the warping shape prediction model is a machine learning model that has been learned, the warping shape prediction model generation unit 96 uses the data set stored in the database 98 as training data to cause the machine learning model to perform machine learning and generates a machine learning model that has been learned. As a machine learning model, commonly used neural networks (including deep learning, convolutional neural networks, etc.), decision tree learning, random forests, support vector regression, etc. can be used. In addition, an integrated model combining multiple models can also be used.

[0134] Fig.14 is a diagram showing an example of a machine learning model using a neural network. The warpage shape prediction model can be used, for example, using Fig.14 It is generated by a general neural network machine learning model as shown. Fig.14 L1, L2, and L3 are the input layer, the intermediate layer, and the output layer, respectively. In particular, if deep learning using a neural network with a multi-layer structure is used, the problem of multicollinearity can be ignored, and other operating parameters that are correlated with the warping shape of the metal strip 1 can be freely selected as inputs, thereby improving the prediction accuracy of the warping shape of the output side of the metal strip 1. Fig.14As shown, as a neural network, a neural network with 2 to 3 intermediate layers and 18 to 512 nodes can be used, and as an activation function, a Sigmoid function can be used. The number of nodes in the output layer can be set in a manner consistent with the number of numerical values ​​output from the warping shape prediction model. For example, in the case where the warping shape prediction model is a model that outputs the warping height at each position in the board width direction, the number of output layers can be set to the number of positions in the board width direction that determine the warping height. In addition, in the case where the warping shape prediction model is a model that outputs a function that approximates the warping height, the number of output layers can be set to the number of coefficients used to determine the function.

[0135] In addition, the data set stored in the database 98 may be divided into training data and test data for machine learning. In this way, by dividing the data set into training data and test data, the warpage shape prediction model generation unit 96 can learn the weight coefficient of the neural network using the training data, and generate the warpage shape prediction model while changing the structure of the neural network (the number of intermediate layers, the number of nodes) so that the accuracy of the output side warpage shape in the test data becomes higher. By generating such a warpage shape prediction model, the prediction accuracy of the output side warpage shape based on the warpage shape prediction model 99 can be improved.

[0136] In addition, the weight coefficient of the warp shape prediction model 99 can be updated, and the update of the weight coefficient can also use the error propagation method. In addition, the warp shape prediction model 99 can be updated to a new warp shape prediction model by relearning, for example, every 6 months or every 1 year. By updating the warp shape prediction model using a data set containing the latest data, even if the state of the skin-pass rolling mill 31 changes over time, the latest state can be reflected in the warp shape prediction model.

[0137] In addition, in the first to third embodiments, the warping shape control device 50 (51, 80), the control controller 18, and the control computer 17 are shown as examples of different devices, but the present invention is not limited thereto. The control controller 18 and the control computer 17 may be one device, and the control controller 18 and the warping shape control device 50 (51, 80) may be one device. Furthermore, the warping shape control device 50 (51, 80), the control controller 18, and the control computer 17 may be one device.

[0138] In addition, as described above, the warping shape control method of the metal strip of the present embodiment can reduce the warping height of the warping shape in which the cross-sectional shape of the metal strip in the plate width direction becomes a W-shaped warping shape or a warping shape approximated by a high-order function. The warping shape in which the cross-sectional shape in the plate width direction becomes a W-shaped warping shape or a warping shape approximated by a high-order function tends to be generated in a high-strength steel plate after rapid cooling. Therefore, the warping shape control method of the metal strip of the present embodiment is preferably applied to the manufacture of a metal strip having a tensile strength of 980 MPa or more.

[0139] Next, a continuous annealing facility 100 capable of implementing the warpage shape control methods of a metal strip according to the first to third embodiments will be described. Fig.15 Schematic diagram showing an example of a continuous annealing facility 100 for manufacturing a cold-rolled steel sheet. Fig.15 The arrows indicate the travel direction of the metal strip 1 .

[0140] The continuous annealing equipment 100 is roughly divided into an input side equipment 20, a furnace body equipment 21, and an output side equipment 24. The surface temper rolling equipment 30 is provided in the output side equipment 24. The continuous annealing equipment 100 including the surface temper rolling equipment 30 is another example of a manufacturing equipment of the metal strip 1 capable of implementing the warpage shape control method of the metal strip 1 of the first embodiment. In addition, when the second embodiment is applied to the continuous annealing equipment 100, the surface temper rolling equipment 30 can be replaced by the surface temper rolling equipment 70, and when the third embodiment is applied to the continuous annealing equipment 100, the surface temper rolling equipment 30 can be replaced by the surface temper rolling equipment 72. The operation of the continuous annealing equipment 100 is controlled by the control computer 17 and the control controller 18.

[0141] The input side equipment 20 has an unwinder 2, a welding machine 3, and an input side looper 4. The furnace body equipment 21 is composed of an annealing device 22 and a reheating device 23. The annealing device 22 has a heating zone 6, a soaking zone 7, and a cooling zone 8, and sometimes has a preheating zone 5 on the upstream side of the heating zone 6. The reheating device 23 has a reheating zone 9, an over-aging zone 10, and a final cooling zone 11, and an induction heating device is arranged in the reheating zone 9. The output side equipment 24 has an output side looper 12, an inspection table 14, and a tension reel 15.

[0142] The heating zone 6 is provided with a device for heating the metal strip 1, and the metal strip 1 is heated to a preset temperature in the range of about 600 to 900°C according to the composition of the metal strip 1. In the heating zone 6, a direct fire or radiation burner is used. The uniform heating zone 7 is provided with a device for maintaining the metal strip 1 at a predetermined temperature. The device for maintaining the metal strip 1 at a predetermined temperature is a device for supplementing the heating capacity of the furnace body heat dissipation and the like.

[0143] The cooling zone 8 is provided with equipment for cooling the metal strip 1 to a predetermined temperature, and as cooling means in the equipment, liquid cooling, gas jet cooling, roller cooling, spray cooling (gas-liquid mixed cooling), etc. are used. Liquid cooling is mostly performed by water cooling (water quenching) using water. Water cooling is a cooling means for cooling the metal strip 1 by immersing it in an immersion water tank provided on the downstream side of the uniform heating zone 7. Gas jet cooling is a cooling means for blowing gas from a nozzle onto the surface of the metal strip 1. Roller cooling is a cooling means for cooling the metal strip 1 by contacting it with a water-cooled roller. Spray cooling is a cooling means for spraying water into a fine mist and cooling it by absorbing its vaporization heat. In spray cooling, the size of the sprayed water droplets is mostly about 0.1 to 1 mm.

[0144] The reheating device 23 is arranged on the downstream side of the cooling zone 8. 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 arranged in the reheating zone 9. The overaging zone 10 is a device for performing an overaging treatment by holding the reheated metal strip 1 for a predetermined time. The final cooling zone 11 is a device for finally cooling the overaged metal strip 1 to near room temperature. However, there are also devices in the continuous annealing equipment that do not have the reheating device 23.

[0145] The output side looper 12 is a device for temporarily storing the metal strip 1 in order to adjust the conveying speed of the metal strip 1 in the furnace body equipment 21 and the processing speed in the output side equipment 24. The dimensional accuracy, surface quality, etc. of the metal strip 1 are inspected at the inspection station 14. The tension reel 15 is a device for winding the metal strip 1 into a coil. The metal strip 1 that is wound into a coil by the tension reel 15 and judged to be qualified by the quality inspection of the inspection station may be shipped as a product coil or sent to a surface treatment equipment for plating the metal strip 1 and subjected to surface treatment. On the other hand, the metal strip 1 that is judged to be unqualified or retained by the quality inspection on the inspection station may be sent to a recoiling line to adjust the size or weight of the metal strip 1, collect samples for quality inspection, inspect the shape / size, rewind the coil, etc.

[0146] The skin-pass rolling equipment 30 is arranged between the delivery-side looper 12 and the inspection table 14. The work rolls 32a and 32b used in the skin-pass rolling mill 31 of the skin-pass rolling equipment 30 need to be replaced at a predetermined timing. By arranging the skin-pass rolling mill 31 on the downstream side of the delivery-side looper 12, the speed change of the metal strip 1 in the furnace equipment 21 when the work rolls 32a and 32b are replaced can be suppressed by the delivery-side looper 12.

[0147] In the continuous annealing equipment 100, the input side warpage shape measuring device 40 can be arranged at any position as long as it is on the downstream side of the furnace equipment 21 and the upstream side of the skin-pass rolling mill 31. This is because there is no equipment that greatly changes the warpage shape of the metal strip 1 on the downstream side of the furnace equipment 21. Fig.15 In the example shown, an input-side warpage shape measuring device 40 is provided on the downstream side of the final cooling zone 11 .

[0148] In addition, when the delivery-side warpage shape measuring device 41 is provided on the downstream side of the skin-pass rolling mill 31, the delivery-side warpage shape measuring device 41 is preferably provided near the inspection station 14. The delivery-side warpage shape of the metal strip 1 may be an inspection item of product quality, so by providing it near the inspection station 14, it is easy to establish correspondence with the results of other quality inspections. In this case, the conveyance distance of the metal strip 1 from the skin-pass rolling mill 31 to the inspection station 14 is usually 20 to 100 m, and the conveyance time from the skin-pass rolling mill 31 to the inspection station 14 is about 2 to 120 seconds.

[0149] The skin-pass rolling mill 31 is preferably arranged downstream of the heating zone 6 that continuously heats the metal strip 1 and the cooling zone 8 that cools the metal strip 1 heated by the heating zone 6. The warping in the plate width direction of the metal strip 1 is generated by the heating of the heating zone 6 and the cooling of the cooling zone 8. Therefore, by arranging the skin-pass rolling mill 31 downstream of the heating zone 6 and the cooling zone 8, the warping height in the plate width direction of the metal strip 1 generated by the cooling of the cooling zone 8 can be reduced.

[0150] Thus, a metal strip manufacturing apparatus capable of implementing the metal strip warping shape control method of the embodiment may be Figure 1 , Fig.10 , Fig.12 The surface polishing equipment 30, surface polishing equipment 70, and surface polishing equipment 72 shown in the figure may also be Fig.15 A continuous annealing apparatus 100 is shown.

[0151] Example

[0152] Next, use Fig.15 The continuous annealing equipment 100 shown is an equipment in which the surface temper rolling equipment 30 is replaced with the surface temper rolling equipment 72 to control the output side warping shape of the metal strip 1. The metal strip 1 used in the embodiment is a high-strength steel plate with a tensile strength TS of 1180 MPa, a plate thickness of 1.6 mm, and a plate width of 921 mm. The operating conditions of the surface temper rolling mill 31 are as follows: the input side tension and the output side tension applied to the metal strip 1 are set to 70 kN, and the elongation is changed in the range of 0.05 to 0.10% by changing the roll gap.

[0153] In the embodiment, a warp shape prediction model 99 is generated in advance by the warp shape prediction model generation unit 96 of the warp shape control device 80, and the warp shape of the metal strip 1 is controlled using the warp shape prediction model 99. The output-side warp shape used to generate the warp shape prediction model 99 is the distribution of the warp height in the plate width direction measured by the output-side warp shape measurement device 41. Specifically, the warp height measured at each position where the metal strip 1 is divided at a pitch of 5 mm in the plate width direction is used. Regarding the input-side warp shape that serves as the input of the warp shape prediction model, the distribution of the input-side warp height measured at each position where the metal strip 1 is divided at a pitch of 5 mm in the plate width direction is also used. As the operating parameters of the skin-pass rolling mill 31 used in the input of the warp shape prediction model, the elongation given to the metal strip 1 by the skin-pass rolling mill 31 and the setting value of the bending force of the work roll bender are used.

[0154] The warpage shape prediction model 99 is generated using a neural network method using the actual data stored in the database 98. As the neural network, a neural network with three intermediate layers and 256 nodes is used, and a sigmoid function is used as an activation function.

[0155] In the warp shape control device 80, the target value of the output-side warp shape set in the determination unit 90 (warp target value) is compared with the output-side warp shape predicted by the warp shape prediction model. With respect to the warp target value, the maximum value of the warp height in the plate width direction of the metal strip 1 is set to 5 mm, and the case where the maximum value of the warp height of the output-side warp shape output by the warp shape prediction model is 5 mm or less is determined as OK (affirmative), and the case where it exceeds 5 mm is determined as NG (negative). When the determination unit 90 determines that the output-side warp shape is NG, the predicted output-side warp shape is output to the approximate curve calculation unit 92.

[0156] The predicted output-side warping shape of the metal strip output from the warping shape prediction model is the warping height at each position divided at 5 mm intervals along the plate width direction, and the approximate curve calculation unit 92 calculates an approximate curve approximating the warping shape by a quadratic curve. Specifically, the approximate curve calculation unit 92 calculates the approximate curve by approximating the prediction result of the output-side warping shape using the following formula.

[0157] H=a1×(xW / 2) 2 +a2···(1)

[0158] Wherein, H is the warpage height (mm), x is the distance from the width end of the plate (mm), W is the plate width of the metal strip (mm), and coefficients a1 and a2 are parameters for determining the approximate curve. Coefficients a1 and a2 are calculated by the least squares method based on the condition that the error between the output side warpage shape predicted by the warpage shape prediction model M and the function of formula (1) is minimized.

[0159] The operating parameter determination unit 94 determines the operating parameters of the skin temper rolling mill 31 that can reduce the warping shape on the delivery side based on the approximate curve of the equation (1) calculated by the approximate curve calculation unit 92. Specifically, when the coefficient a1 of the equation (1) is positive, the warping height near the end of the plate width is larger than that in the middle of the plate width, and therefore the setting value is determined so that the bending force of the work roll bender of the skin temper rolling mill 31 is smaller than the current setting value. On the other hand, when the coefficient a1 of the equation (1) is negative, the warping height near the end of the plate width is smaller than that in the middle of the plate width, and therefore the setting value is determined so that the bending force of the work roll bender of the skin temper rolling mill 31 is larger than the current setting value. The warping shape control device 80 outputs the setting value of the bending force of the work roll bender determined by the operating parameter determination unit 94 to the control controller 18. The control controller 18 multiplies the setting value of the bending force obtained from the warping shape control device 80 by a gain used in normal proportional integral control and outputs the result to the skin temper rolling mill 31, thereby changing the operating conditions of the skin temper rolling mill 31.

[0160] The processing of the operating parameter determination unit 94 is 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 way, the output warping shape of the metal strip 1 in the longitudinal direction is controlled.

[0161] As a result, for the 20 metal strips 1 manufactured, the pass rate of the output side warping shape being below the warping target value over the entire length in the longitudinal direction was 100%, which was significantly improved compared with the previous pass rate of 85% when the embodiment was not applied.

[0162] Description of Reference Numerals

[0163] 1 Metal belt

[0164] 2 Unwinding machine

[0165] 3. Welding Machine

[0166] 4 Input side looper

[0167] 5 Preheating Zone

[0168] 6 Heating Zones

[0169] 7. Heat distribution area

[0170] 8 Cooling Zone

[0171] 9 Reheating Zone

[0172] 10 Expiration zone

[0173] 11 Final cooling zone

[0174] 12 Output side looper

[0175] 14. Examination Table

[0176] 15 Tension reel

[0177] 17 Control Computer

[0178] 18 Control Controller

[0179] 21 Furnace equipment

[0180] 22 Annealing equipment

[0181] 23 Reheating equipment

[0182] 24 Output side equipment

[0183] 30 Surface polishing equipment

[0184] 31. Surface polishing mill

[0185] 32a Working Roll

[0186] 32b working roll

[0187] 33a Support roller

[0188] 33b Support roller

[0189] 34 Pressing device

[0190] 35 Bearing box

[0191] 36 Input side tension roller

[0192] 37 Input side tension meter

[0193] 38 Output side tension meter

[0194] 39 Output side tension roller

[0195] 40 Input side warpage shape measurement device

[0196] 41 Output side warpage shape measurement device

[0197] 42 Load detector

[0198] 43a Working roll support

[0199] 43b Working roll support

[0200] 44 Laser scanning laser rangefinder

[0201] 50 Warp shape control device

[0202] 51 Warp shape control device

[0203] 52 Control Department

[0204] 53 Control Department

[0205] 54 Input section

[0206] 56 Output

[0207] 58 Storage

[0208] 60 Acquisition

[0209] 62 Approximate curve calculation unit

[0210] 64 Operation parameter determination unit

[0211] 70 Surface polishing equipment

[0212] 72 Surface polishing equipment

[0213] 80 Warp shape control device

[0214] 82 Control Department

[0215] 84 Storage

[0216] 86 Acquisition Department

[0217] 88 Warpage shape prediction department

[0218] 90 Judgment Department

[0219] 92 Approximate curve calculation unit

[0220] 94 Operation parameter determination unit

[0221] 96 Warpage shape prediction model generation unit

[0222] 98 Database

[0223] 99 Warpage Shape Prediction Model

[0224] 100 Continuous annealing equipment

Claims

1. A method for controlling the warping shape of a metal strip, in a metal strip manufacturing facility including a skin-pass rolling mill for correcting the shape of a continuously conveyed metal strip and a warping shape measuring device for measuring the warping shape of the metal strip, wherein the warping shape of the metal strip at the downstream side of the skin-pass rolling mill, i.e., the warping shape at the output side, is controlled, wherein: calculating an approximate curve of the warping shape of the metal strip using an approximation method selected from a parabola approximation, a circular arc approximation, and an envelope approximation, Based on the calculated approximate curve, operating parameters of the skin temper rolling mill are set that can reduce the warp height of the output-side warp shape.

2. The method for controlling the warping shape of a metal strip according to claim 1, wherein: The warping shape measuring device is an input side warping shape measuring device for measuring the input side warping shape of the metal strip on the upstream side of the skin-pass rolling mill. The warping shape control method of the metal strip calculates an approximate curve of the input-side warping shape measured by the input-side warping shape measuring device.

3. The method for controlling the warping shape of a metal strip according to claim 1, wherein: The warping shape measuring device is an output-side warping shape measuring device for measuring the output-side warping shape of the metal strip at the downstream side of the skin-pass rolling mill. The warping shape control method of the metal strip calculates an approximate curve of the output-side warping shape measured by the output-side warping shape measuring device.

4. The method for controlling the warping shape of a metal strip according to claim 1, wherein: The warping shape measuring device is an input side warping shape measuring device for measuring the input side warping shape of the metal strip on the upstream side of the skin-pass rolling mill. The warping shape control method of the metal strip uses a warping shape prediction model to predict the output side warping shape and calculates an approximate curve of the predicted output side warping shape. The warping shape prediction model takes as input data including the input side warping shape measured by the input side warping shape measuring device and at least one of the operating parameters of the surface smooth rolling mill, and takes as output the output side warping shape.

5. The method for controlling the warping shape of a metal strip according to any one of claims 1 to 4, wherein: The manufacturing equipment is a continuous annealing equipment for heat treatment of the metal strip, The temper rolling mill is arranged on the downstream side of a heating zone for heating the metal strip and a cooling zone for cooling the metal strip heated in the heating zone.

6. A method for manufacturing a metal strip, wherein: A metal strip having a tensile strength of 980 MPa or more is produced using the warpage shape control method for a metal strip according to any one of claims 1 to 4.

7. A method for manufacturing a metal strip, wherein: The warping shape control method of a metal strip according to claim 5 is used to produce a metal strip having a tensile strength of 980 MPa or more.

8. A warping shape control device for a metal strip, in a metal strip manufacturing facility including a skin-pass rolling mill for correcting the shape of a continuously conveyed metal strip and a warping shape measuring device for measuring the warping shape of the metal strip, wherein the warping shape of the metal strip at the downstream side of the skin-pass rolling mill, i.e., the warping shape at the output side, is controlled, wherein: The warping shape control device of the metal strip comprises: an acquisition unit that acquires the warpage shape measured by the warpage shape measuring device; an approximate curve calculation unit that calculates an approximate curve of the warped shape using an approximation method selected from parabola approximation, circular arc approximation, and envelope approximation; and An operating parameter determination section determines the operating parameters of the skin temper rolling mill based on the approximate curve so that the warp height of the output-side warp shape becomes small.

9. The warping shape control device of a metal strip according to claim 8, wherein: The warping shape measuring device is an input side warping shape measuring device for measuring the input side warping shape of the metal strip on the upstream side of the skin-pass rolling mill. The acquisition unit acquires the input-side warping shape measured by the input-side warping shape measuring device, and the approximate curve calculation unit calculates an approximate curve of the input-side warping shape.

10. The warping shape control device of a metal strip according to claim 8, wherein: The warping shape measuring device is an output-side warping shape measuring device for measuring the output-side warping shape of the metal strip at the downstream side of the skin-pass rolling mill. The acquisition unit acquires the output-side warping shape measured by the output-side warping shape measuring device, and the approximate curve calculation unit calculates an approximate curve of the output-side warping shape.

11. The warping shape control device of a metal strip according to claim 8, wherein: The warping shape control device of the metal strip further comprises a warping shape prediction unit, The warping shape measuring device is an input side warping shape measuring device for measuring the input side warping shape of the metal strip on the upstream side of the skin-pass rolling mill. The acquisition unit acquires the input side warping shape measured by the input side warping shape measuring device, the warping shape prediction unit predicts the output side warping shape using a warping shape prediction model, the warping shape prediction model takes as input input data including the input side warping shape and at least one of the operating parameters of the surface temper rolling mill, and takes as output the output side warping shape, and the approximate curve calculation unit calculates an approximate curve of the predicted output side warping shape.

12. The warping shape control device for a metal strip according to any one of claims 8 to 11, wherein: The manufacturing equipment is a continuous annealing equipment for heat treatment of the metal strip, The temper rolling mill is arranged on the downstream side of a heating zone for heating the metal strip and a cooling zone for cooling the metal strip heated in the heating zone.

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