Image display method for steel sheet, rolling control method for steel sheet, steel sheet manufacturing method, quality control method for steel sheet, image display system for steel sheet, rolling equipment for steel sheet, and steel sheet manufacturing equipment

Abstract

To provide an image display method for steel sheet easy to apply and capable of reducing generation of tail end drawing, a rolling control method for steel sheet, a steel sheet manufacturing method, a quality control method for steel sheet, an image display system for steel sheet, rolling equipment for steel sheet, and manufacturing equipment for steel sheet.SOLUTION: An image display method for displaying an image of a steel sheet rolled by a tandem rolling mill provided with a plurality of mill stands includes: an imaging step which captures an image of an end of a steel sheet going through a mill stand to be controlled, engaging a next mill stand, and tension control that is started by receiving a heat radiation light emitted by the steel sheet with an imaging device having an imaging frame rate 90 frames per second installed outside a path line of the steel sheet; and a display step generating an image obtained by the imaging step time serially with a display device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for displaying an image of a steel plate, a method for controlling rolling of a steel plate, a method for manufacturing a steel plate, a method for controlling the quality of a steel plate, an image display system for a steel plate, a steel plate rolling facility, and a steel plate manufacturing facility. [Background technology]

[0002] There is a high demand for shape control of steel materials in steelmaking processes from the perspective of operational stability, product quality assurance, etc. Shape measurement during hot rolling, which is used to create the desired shape of the product, is particularly important because it leads to improved product quality and operational stability by providing feedback for initial setting of rolling conditions and for rolling control during rolling.

[0003] A problem called tail end squeezing can occur in the finish rolling process of a hot-rolled steel sheet production line. Specifically, tail end squeezing occurs when the tail end of a hot-rolled steel sheet comes into contact with the steel sheet guide on the entry side of the rolling mill as it leaves the rolling mill, causing it to buckle and bend while being rolled. When this problem occurs, the shape of the tail end becomes unstable and there is a possibility that the rolling rolls may be damaged. For these reasons, the occurrence of tail end squeezing leads to a decrease in yield and productivity due to the need to inspect the rolling rolls.

[0004] Therefore, in order to reduce the above-mentioned tail end narrowing, for example, Patent Document 1 discloses a method of reducing meandering by installing a two-dimensional camera above between mill stands (rolling stands) and performing leveling feedback control by directly measuring the amount of meandering at the tail end of the steel plate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-141956 [Non-patent literature]

[0006] [Non-Patent Document 1] Kaneshige, "Heat Measurement Using a Radiation Thermometer", Molding and Processing, Society of Plastics Processing, 2020, Vol. 32, No. 4, pp. 121-124 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technology disclosed in Patent Document 1 requires extremely high responsiveness because it detects the tail end of the steel plate and implements control actions within less than one second from the time the tail end leaves the previous stand to the time it leaves the next stand, making it very difficult to apply the technology disclosed in Patent Document 1 to actual equipment.

[0008] The present invention has been made in view of the above, and aims to provide a method for displaying an image of a steel plate, a method for controlling the rolling of a steel plate, a method for manufacturing a steel plate, a method for controlling the quality of a steel plate, an image display system for a steel plate, a steel plate rolling facility, and a steel plate manufacturing facility that are easy to apply and can reduce the occurrence of tail end squeezing. [Means for solving the problem]

[0009] (1) The image display method of the present invention is an image display method for displaying an image of a steel sheet rolled by a tandem rolling mill having a plurality of mill stands, an imaging step in which an imaging device having an imaging frame rate of 90 frames per second or more is installed outside the pass line of the steel sheet and receives thermal radiation light emitted from the steel sheet, thereby imaging the leading edge of the steel sheet from when it leaves the mill stand to be controlled and is bitten into the next mill stand until tension control is started; a display step of reproducing the images obtained in the imaging step in time series by a display device; Includes.

[0010] (2) Furthermore, the method for displaying an image of a steel sheet according to the present invention is the method for displaying an image of a steel sheet according to the above (1), When a reference plane of the surface of the steel plate is defined as a plane α, an angle θ formed between the plane α and the optical axis of the imaging device is set in a range of 0° to 45°, The angle φ formed by the orthogonal projection of the optical axis of the imaging device onto the plane α and the conveying direction p of the steel plate is set in the range of 70° to 110°.

[0011] (3) Furthermore, the method for displaying an image of a steel sheet according to the present invention is the method for displaying an image of a steel sheet according to the above (1) or (2), A plurality of the imaging devices are installed so as to capture images of the steel plate between a plurality of consecutive mill stands.

[0012] (4) The method for controlling rolling of steel plate according to the present invention includes a control step of controlling the mill stand to be controlled by a control device while the steel plate is being rolled in the mill stand to be controlled, using an image obtained by the method for displaying an image of steel plate described in any one of (1) to (3) above.

[0013] (5) A method for producing a steel sheet according to the present invention produces the steel sheet while controlling the threading of the steel sheet by the method for controlling rolling of a steel sheet according to (4) above.

[0014] (6) The method for controlling the quality of a steel sheet according to the present invention controls the quality of the steel sheet while controlling the threading of the steel sheet by the method for controlling the rolling of a steel sheet described in (4) above.

[0015] (7) An image display system for a steel plate according to the present invention is an image display system for displaying an image of a steel plate rolled by a tandem rolling mill having a plurality of mill stands, an imaging device that is installed outside the pass line of the steel sheet, has an imaging frame rate of 90 frames per second or more, and receives thermal radiation light emitted from the steel sheet to capture images of the leading edge of the steel sheet from when it passes through the mill stand to be controlled and is bitten into the next mill stand until tension control is started; a display device that plays back images obtained by the imaging device in time series; Equipped with.

[0016] (8) A steel plate rolling facility according to the present invention includes the steel plate image display system described in (7) above.

[0017] (9) A steel plate manufacturing facility according to the present invention includes the steel plate image display system described in (7) above. [Effects of the Invention]

[0018] In the steel plate image display method, steel plate rolling control method, steel plate manufacturing method, steel plate quality control method, steel plate image display system, steel plate rolling equipment, and steel plate manufacturing equipment according to the present invention, an image of the leading edge of a steel plate passing between mill stands is captured by an imaging device from the side in the steel plate transport direction and displayed at any timing. This makes it possible to grasp the shape of the leading edge of the steel plate before rolling by the next mill stand. Then, by adjusting the leveling based on this shape tendency of the steel plate before rolling, it is possible to reduce the occurrence of tail end reduction. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a rolling facility for a steel plate equipped with an image display system for a steel plate according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing an example of the shape of the elongated steel sheet. [Figure 3] FIG. 3 is a diagram showing the positional relationship between the conveyance direction of the steel plate and the imaging device, as viewed from above, in the steel plate image display system according to the embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the positional relationship between the conveyance direction of the steel plate and the imaging device in the steel plate image display system according to the embodiment of the present invention, viewed from the same direction as the conveyance direction of the steel plate. [Figure 5] FIG. 5 is a flowchart showing the flow of a method for controlling rolling of a steel plate according to an embodiment of the present invention. [Figure 6]Figure 6 is a diagram showing images acquired by an imaging device of a steel plate image display system according to an embodiment of the present invention, where (a) is a diagram showing an image acquired when a steel plate is not present within the field of view, and (b) is a diagram showing an image when a steel plate is discharged from a controlled mill stand and its leading edge enters the steel plate detection area A. [Figure 7] Figure 7 shows an example of an image actually acquired by an imaging device of a steel plate image display system according to an embodiment of the present invention, where (a) is an image capturing the moment when the leading edge of the steel plate passes through the mill stand to be controlled and becomes engaged in the next mill stand, and (b) is an image capturing the moment when the leading edge of the steel plate becomes engaged in the next mill stand and tension control begins. DETAILED DESCRIPTION OF THE INVENTION

[0020] A method for displaying an image of a steel plate, a method for controlling rolling of a steel plate, a method for manufacturing a steel plate, a quality control method for a steel plate, an image display system for a steel plate, a rolling facility for a steel plate, and a manufacturing facility for a steel plate according to embodiments of the present invention will be described with reference to the drawings. Note that the components in the following embodiments include those that are easily replaceable by a person skilled in the art, or those that are substantially identical.

[0021] First, the premise of the present invention will be explained with reference to Fig. 1. Until now, in order to suppress tail end reduction of a steel plate, operators have visually checked the shape of the steel plate between the mill stands and adjusted the leveling of the tandem rolling mill (adjusting the reduction ratios of the work side and drive side) based on the results. However, the time it takes for the tail end of the steel plate to pass between the mill stands is less than one second, and considering the need to perform leveling adjustments, it has been extremely difficult to reduce tail end reduction using this method.

[0022] Therefore, the inventors have conducted research and found the following: First, drawing (rolling a steel sheet in a folded state) mostly occurs at the tail end. Therefore, as shown in Figure 1, it is sufficient to perform appropriate leveling adjustment before the tail end of the steel sheet S passes through the mill stand 1 to be controlled (hereinafter referred to as the "controlled mill stand")

[0023] Furthermore, in order to perform appropriate leveling adjustment, it is desirable to know the shape of the steel sheet S that appropriately reflects the rolling state of the mill stand. However, in reality, when the steel sheet S is sandwiched between the mill stand 1 to be controlled and the next mill stand (hereinafter referred to as the "next mill stand") 2, a control (tension control) is performed in which the looper rises from below to apply tension. Therefore, while the steel sheet S is between the mill stand 1 to be controlled and the next mill stand 2, it is not possible to know the state of the mill stand 1 to be controlled.

[0024] On the other hand, the inventors have found that the shape of the steel sheet S from "when the leading edge of the steel sheet S passes through the mill stand 1 to be controlled, bites into the next mill stand 2, and just before the looper comes into contact with the steel sheet S" reflects the rolling state of the mill stand 1 to be controlled. Therefore, in the present invention, images of this "when the leading edge of the steel sheet S passes through the mill stand 1 to be controlled, bites into the next mill stand 2, and just before the looper comes into contact with the steel sheet S" are taken in chronological order, and these chronological images are played back to an operator, for example.

[0025] As a result, for example, an operator can adjust the leveling of the mill stand 1 to be controlled as needed. If the leveling adjustment is completed just before the tail end of the steel sheet S passes through the mill stand 1 to be controlled, the steel sheet S will be properly leveled when the tail end passes through, and the possibility of tail end squeezing occurring will be extremely low. Taking these points into consideration, an embodiment of the present invention will be described below.

[0026] (Image display system) The configuration of the steel plate image display system according to the embodiment will be described with reference to Figures 1 to 4. Figure 1 shows a schematic configuration of a steel plate rolling facility equipped with the steel plate image display system according to the embodiment. Note that the image display system may be applied to steel plate manufacturing facilities in addition to the steel plate rolling facility shown in Figure 1.

[0027] The steel plate rolling equipment of the embodiment comprises a mill stand 1 to be controlled, a next mill stand 2, an imaging device 3, an image processing device 4, a display device 5, and a control device 6. The steel plate image display system of the embodiment is for displaying an image of a steel plate S being rolled by a tandem rolling mill having multiple mill stands (the mill stand 1 to be controlled, the next mill stand 2), and comprises the imaging device 3, the image processing device 4, and the display device 5.

[0028] The imaging device 3 is used to capture images (still images, video images) of the leading edge of the steel sheet S passing between the mill stand 1 to be controlled and the next mill stand 2. The imaging device 3 is installed outside the pass line of the steel sheet S. As will be described later, the imaging device 3 is composed of a camera having an imaging frame rate of 90 frames per second or more. Details of the imaging device 3 are described below.

[0029] <Frame rate of imaging device> The steel sheet S is transported at a maximum transport speed of, for example, 20 m / s. Therefore, even if an image of the leading edge of the steel sheet S is simply played back at the same frame rate as when the image was taken, it is obviously impossible to visually confirm the shape. Therefore, when displaying an image taken by the imaging device 3, it is desirable to lower the frame rate during playback.

[0030] Generally, the human eye is said to see images at about 30 fps, and at this display frame rate, it is possible to confirm the shape of the steel sheet S without any sense of incongruity. Furthermore, when a test was carried out by displaying images actually captured by the imaging device 3, it was found that reducing the display frame rate to about 1 / 3 to 1 / 5 was effective for visually confirming the shape.

[0031] Therefore, the imaging frame rate required for the imaging device 3 is in the range of 90 fps to 150 fps, and the imaging device 3 selected has an imaging frame rate of 90 fps or higher.

[0032] <Positional relationship between the imaging device and the steel plate> The shape of the leading edge of the steel sheet S that is to be visualized in the present invention is the state of elongation of each of the two edges in the width direction of the steel sheet S. For example, if the edge on the drive side (machine side) is elongated compared to the edge on the work side (operator side), the outline of the edge of the steel sheet S will be confirmed to have a wavy shape, as shown in Figure 2. By visualizing such a shape of the steel sheet S, it becomes possible to perform leveling adjustments to reduce tail end reduction.

[0033] 3 and 4 show an example of the positional relationship between the imaging device 3 and the steel sheet S. Fig. 3 shows the positional relationship between the imaging device 3 and the steel sheet S as seen from above. Fig. 4 shows the positional relationship between the imaging device 3 and the steel sheet S as seen from the same direction as the conveying direction p of the steel sheet S. In Figs. 3 and 4, the reference plane on the surface of the steel sheet S, i.e., the plane parallel to the conveying table of the steel sheet S, is defined as α (plane α), the angle between the optical axis of the imaging device 3 and the plane α is defined as θ (light-receiving angle θ), and the angle between the orthogonal projection of the optical axis of the imaging device 3 onto the plane α and the conveying direction p is defined as φ.

[0034] The purpose of this embodiment is to capture an image of the steel sheet S passing between the mill stands of a tandem rolling mill (between the mill stand 1 to be controlled and the next mill stand 2). Therefore, it is preferable that the angle φ be closer to 90°. The first reason is that the distance between the mill stands is only a few meters, and the mill stand itself is a large structure. Therefore, as the angle φ becomes farther from 90°, the width edge of the steel sheet S on the side farther from the imaging device 3 (the drive side) becomes less visible. The second reason is that if the angle φ is extremely small or large within the range of 0 to 180°, the mill stand will block the field of view of the imaging device 3, making it difficult to capture an image of the steel sheet S. Therefore, the angle φ is preferably in the range of 70 to 110°.

[0035] Furthermore, it is preferable that the light-receiving angle θ is close to 0° within the range in which the outlines of both edges in the width direction of the steel sheet S are captured within the field of view of the imaging device 3. This is because the shape of the leading edge of the steel sheet S that is to be visualized in the present invention is an elongated shape that appears like a wave on each of both edges in the width direction, as shown in Figure 2, and this is to make it possible to easily obtain the height component of the wave. Therefore, the closer the light-receiving angle θ is to 0°, the easier it is to confirm the wave shape. It is also preferable that the light-receiving angle θ is set in the range of 0° to 45°.

[0036] Furthermore, it is desirable to use a telephoto lens when capturing images, thereby increasing the distance as much as possible between the steel sheet S to be measured and the imaging device 3. The reason for this is that by placing the imaging device 3 as far away as possible from the production line, it is possible to reduce differences in optical conditions such as the light-receiving angle θ and the angle φ in the width direction of the steel sheet S, i.e., at both edge portions. Furthermore, by placing the imaging device 3 as far away as possible from the production line, it is possible to install the imaging device 3 in a good environment with less influence from high heat and dust, which has the advantage of allowing maintenance to be performed without stopping the equipment.

[0037] <Number of imaging devices installed> Basically, one imaging device 3 needs to be installed for each mill stand 1 to be controlled. However, if multiple mill stands 1 to be controlled are installed, it is preferable to install an imaging device 3 for each mill stand 1 to be controlled. The appropriate number of cameras to be installed will be explained below.

[0038] First, a hot rolling finishing line is made up of multiple mill stands, and the steel sheet S is rolled thinner from the first mill stand to the second mill stand. The thinner the steel sheet S, the more likely it is that meandering will occur due to elongation of the steel sheet S, so it is preferable that the mill stand 1 to be controlled is as late as possible.

[0039] On the other hand, tail end narrowing does not necessarily occur in the final mill stand, and may occur due in part to a misalignment in the leveling balance of each mill stand from the front to the rear. Therefore, it is preferable to install imaging devices 3 between multiple mill stands rather than limiting the monitoring target to a single mill stand. In other words, it is preferable to install multiple imaging devices 3 so as to capture images of the steel sheet S between multiple consecutive mill stands.

[0040] In this case, for example, a complete image display system as shown in Figure 1 may be prepared for each installation location, or an image processing device 4 with the performance to withstand the control and image processing of multiple imaging devices 3 may be prepared, and multiple imaging devices 3 may be connected to a single image processing device 4.

[0041] The image processing device 4 is realized by, for example, a general-purpose computer such as a workstation or a personal computer. The display device 5 is realized by, for example, a liquid crystal display (LCD), an organic light-emitting display (OLED), etc. The control device 6 is an operating device for adjusting the leveling of the mill stand 1 to be controlled.

[0042] (Rolling control method) The flow of a steel plate rolling control method executed by a steel plate rolling facility equipped with an image display system according to an embodiment of the present invention will be described with reference to Figures 5 to 7. The steel plate rolling control method includes an imaging step, a display step, and a control step. The image display method according to the embodiment performs steps S1 to S6 of steps S1 to S8 shown in Figure 5, excluding steps S7 and S8.

[0043] First, when the leading edge of the steel sheet S is discharged from the mill stand 1 to be controlled (step S1), an imaging step is initiated (step S2). In the imaging step, the imaging device 3 receives thermal radiation light emitted from the steel sheet S, thereby capturing images of the leading edge of the steel sheet S from when it leaves the mill stand 1 to be controlled and becomes engaged in the next mill stand 2 until tension control begins. After the imaging step begins, the leading edge of the steel sheet S becomes engaged in the next mill stand 2 (step S3), and tension control of the steel sheet S begins (step S4), and the imaging step ends (step S5).

[0044] Subsequently, a display step is carried out (step S6). In the display step, the images obtained in the imaging step are played back in time series by the display device 5.

[0045] Subsequently, a control step is carried out (step S7). In the control step, the image obtained in the imaging step is used by the control device 6 to control (leveling adjustment) the mill stand 1 to be controlled while the steel sheet S is being rolled in the mill stand 1 to be controlled. After the control step is started, when the tail end of the steel sheet S is discharged from the mill stand 1 to be controlled (step S8), this process is completed.

[0046] <Image acquisition timing> The timing of image acquisition in the imaging step (step S2) will be explained below. The timing of image acquisition is the period from immediately after the leading edge of the steel sheet S is discharged from the mill stand 1 to be controlled until the leading edge of the steel sheet S bites into the next mill stand 2 and tension control starts. The reason for this is that tension control by the looper starts immediately after the steel sheet S bites into the next mill stand 2, making the shape of the steel sheet S invisible.

[0047] Therefore, it is conceivable to control the imaging trigger or image acquisition timing of the imaging device 3 by using, for example, load information from the rolling of the controlled mill stand 1 and the next mill stand 2, or by using a separate detection sensor for the steel sheet S. However, these methods require coordination with existing systems and newly added sensors, and it is expected that construction work and cable extension will become a bottleneck. Therefore, if possible, it is preferable to use an independent system with the configuration shown in Figure 1, as this will simplify the system.

[0048] Therefore, in this embodiment, a method is used in which the image acquisition timing is automatically determined from the image by the image processing device 4 shown in Fig. 1. As described above, the image processing device 4 is realized by a general-purpose computer such as a workstation or a personal computer, and may be installed near the imaging device 3.

[0049] In this method, the imaging device 3 constantly captures images between the mill stands, and the state of the obtained images is monitored by the image processing device 4, which recognizes that the steel sheet S has entered the field of view (imaging field of view), i.e., that the brightness of the self-luminous component emitted from the steel sheet S has been detected. As a result, images are saved only while the leading edge of the steel sheet S passes between the mill stands.

[0050] Details of this method will be described with reference to Figure 6. Figure 6(a) shows an image acquired when a steel sheet S is not present within the field of view of the imaging device 3. A steel sheet detection area A is set on the pass line of the steel sheet S in this image and near the mill stand 1 to be controlled. The steel sheet detection area A is prepared to detect the brightness of the self-luminous component emitted by the steel sheet S and to monitor the brightness within the area. Here, to avoid errors in the timing of image storage due to the influence of ambient light, it is effective to set a threshold value for noise removal for the brightness detected within the steel sheet detection area A or to calculate and use the average brightness within the steel sheet detection area A.

[0051] Next, (b) of Figure 6 shows a state in which the leading edge of the steel sheet S enters the steel sheet detection area A immediately after it has been discharged from the mill stand 1 to be controlled. In this case, the steel sheet detection area A detects the brightness of the self-luminous component emitted by the steel sheet S, and therefore starts capturing and saving images (see step S2 in Figure 5). The timing to end capturing and saving images (see step S5 in Figure 5) may take into account the time until tension control between the mill stands begins, and may be, for example, after a specified time has elapsed since the start of image saving, or may be immediately after a specified number of images have been acquired.

[0052] <Ensuring sufficient light when capturing images> The following describes how to ensure the amount of light in the imaging step (step S2). It is necessary to ensure the amount of light to obtain a clear image. As mentioned above, the steel sheet S passes through the finishing mill stand at a maximum speed of 20 m / s, but in order to obtain a clear image of such a fast-moving object without blurring, the exposure time must be set short. For example, the exposure time to allow for a blurring of 2 mm is only 0.1 ms, and shortening the exposure time also results in a very small amount of received light.

[0053] Therefore, it is preferable to take advantage of the fact that the temperature of the steel sheet S at the delivery side of the hot finish rolling mill, which is the object of imaging, is approximately 900°C. For example, as shown in FIG. 5 of Non-Patent Document 1, the wavelength of thermal radiation light at approximately 900°C (1200K) shows a peak value in the infrared region. Therefore, since the sensitivity is low in the visible region (0.4 μm to 0.7 μm), it is preferable to select an imaging device 3 that has imaging sensitivity in the near-infrared region (0.8 μm to 1.0 μm). By using such an imaging device 3, even if the exposure time is set to 0.1 ms, a sufficient amount of light can be obtained to identify the shape of the steel sheet S, making it possible to acquire clear images without blur.

[0054] <Display step details> The display step (step S6) will be described in detail below. In the display step, the images captured by the imaging device 3 are stored in the image processing device 4, and then these images are processed for display and displayed as video on the display device 5. The display device 5 may be one that is capable of general display processing at about 30 fps. Furthermore, since the purpose is for the operator to adjust the leveling of the tandem rolling mill while checking the display device 5, it is preferable to install the display device 5 in a place where it can be easily seen near the control device 6, such as inside the cab.

[0055] Furthermore, with regard to the image display, the display frame rate is set to 30 fps, the imaging time is fixed at 1 second from when the leading edge of the steel sheet S enters the field of view of the imaging device 3, and the imaging frame rate is variably adjusted within a range of 90 fps to 150 fps. That is, during the 1 second it takes for the leading edge of the steel sheet S to pass between the mill stands, slow-motion images are displayed at a playback speed of about 1 / 3 to 1 / 5 of the actual speed, and furthermore, the slow-motion images are repeatedly displayed until the next steel sheet S enters the field of view. This allows the shape of the steel sheet S to be checked multiple times, so the operator will not miss anything.

[0056] Furthermore, since the brightness of the steel sheet S varies depending on the temperature, it is also effective to correct the brightness of the acquired image before displaying it. Specifically, for example, a method can be used in which the brightness of the entire image is multiplied by a fixed value so that a representative value such as the maximum value, average value, median value, or percentile of the brightness of the entire image becomes a target value. Furthermore, dark current correction may be performed before multiplying the brightness of the entire image by a fixed value.

[0057] Furthermore, the temperature value may be predicted and the exposure time may be adjusted in advance in the imaging step. Also, for example, by using a percentile method to adjust the brightness so that the top 2% of the brightness values ​​when all brightness values ​​in the image are sorted are 200, it becomes possible to display an image with stable brightness regardless of temperature changes of the steel sheet S.

[0058] Figure 7 shows an example of an image actually captured under the above conditions. Figure 7(a) is an image capturing the moment when the leading edge of the steel sheet S leaves the controlled mill stand 1 and becomes engaged with the next mill stand 2. Figure 7(b) is an image capturing the period from when the leading edge of the steel sheet S becomes engaged with the next mill stand 2 until tension control begins. In Figure 7(b), the edge profile of the drive side appears to be wavy compared to the edge profile of the work side, which indicates that the drive side of the steel sheet S is elongated compared to the work side.

[0059] In addition, although Fig. 7 only displays an image of the steel sheet S, it is also possible to calculate elongation indices of both edges, such as steepness and elongation rate, by image processing, and display this information together with the image and time as numerical values ​​or a graph chart. This makes it possible to more clearly show the shape of both edges of the steel sheet S to the operator.

[0060] <Details of control steps> The control step (step S7) will be described in detail below. In the control step, for example, an operator uses the control device 6 to adjust the leveling of the mill stand 1 to be controlled based on the information visualized in the imaging step and the display step.

[0061] Here, the shape tendency that appears at the front end of the steel sheet S will continue until the tail end is removed unless the rolling settings are adjusted. Therefore, if the shape of the front end of the steel sheet S can be grasped, appropriate leveling adjustment can be made to suppress tail end reduction until the tail end is removed.

[0062] For example, when the shape of the steel plate S is recognized as shown in Figure 7(b), the edge on the drive side is elongated, meaning that the load balance is biased toward the drive side, so the load balance is adjusted to the work side. By performing these controls, it is now possible to make appropriate leveling adjustments to the mill stand 1 being controlled according to the shape of the steel plate S being transported between mill stands, which was previously difficult, and it is expected that tail-end squeezing will be suppressed.

[0063] <When multiple mill stands to be controlled are installed> In the steel sheet rolling control method according to the embodiment, a case will be described in which a plurality of control target mill stands 1 are installed. In this case, each time the leading edge of the steel sheet S passes through each control target mill stand 1, the shape of the steel sheet S is displayed on the display device 5 by a display step.

[0064] The operator checks the displayed images between each mill stand and, based on the results of this check, determines the mill stand 1 to be controlled that requires leveling adjustment. Leveling adjustment operations are then performed on the determined mill stand 1 to be controlled. In this case, if there are multiple mill stands 1 to be controlled that require leveling adjustment operations, they may be operated sequentially from the upstream or downstream side of the row of mill stands, or operations may be performed by setting priorities based on the degree of shape. In either case, the condition is that the tail end has not been discharged from the mill stand 1 to be controlled.

[0065] <When the control steps are performed automatically> In the explanation so far, the operator checks the image displayed by the display step, determines whether or not leveling adjustment is necessary for the mill stand 1 to be controlled, and performs the leveling adjustment manually, but leveling adjustment can also be performed automatically without the intervention of the operator.

[0066] In this case, the image processing device 4 analyzes the image acquired in the imaging step to determine whether or not leveling adjustment is required for the mill stand 1 to be controlled, and transmits the determination result to the control device 6. Then, when the control device 6 receives a determination result from the image processing device 4 that leveling adjustment is required for the mill stand 1 to be controlled, it performs leveling adjustment for the mill stand 1 to be controlled. Note that the method for determining whether or not leveling adjustment is required in the image processing device 4 is not particularly limited, and machine learning techniques such as deep learning can be used, for example.

[0067] (Details of machine learning technology) Utilizing machine learning technology can be useful for improving the accuracy of leveling adjustments and for detecting signs of abnormalities such as rolling troubles. A major advantage of machine learning is that it can discover rules that humans cannot recognize, and it is expected to improve the accuracy of predictions that have previously relied on experience.

[0068] <Configuration> When applying machine learning technology to the steel plate rolling control method according to this embodiment, a trained machine learning model is stored, for example, in an image processing device 4. Then, the output obtained by the machine learning model is displayed on a display device 5 to present information to an operator. Furthermore, when an operation amount for a control device 6 can be obtained as the output of the machine learning model, leveling control is performed directly by inputting the operation amount into the control device 6. Each operation pattern will be described below.

[0069] <Operation Pattern 1> In operation pattern 1, before performing the image display method of the present invention, a machine learning model is generated in advance by performing machine learning using an image of the steel sheet S captured by the imaging device 3 as an input value and the actual result of whether or not the tail end has been drawn at that time as an output value. This image of the steel sheet S is an image taken from the time the leading edge of the steel sheet S leaves the mill stand 1 to be controlled and is bitten into the next mill stand 2 until tension control is started.

[0070] Thereafter, in the image display method or system according to the present invention, the image of the steel sheet S captured by the imaging device 3 in the imaging step (steps S2 to S5) is input into a trained machine learning model to output information regarding the occurrence or non-occurrence of tail end reduction, and the information is displayed on the display device 5. Subsequently, based on the information regarding the occurrence or non-occurrence of tail end reduction, for example, an operator uses the control device 6 to adjust the leveling of the mill stand 1 to be controlled. Note that in operation pattern 1, instead of the image of the steel sheet S, an edge elongation index obtained by processing the image of the steel sheet S may be input into the machine learning device to perform learning and prediction.

[0071] <Operation Pattern 2> In operation pattern 2, before performing the image display method of the present invention, machine learning is performed using an image of the steel sheet S captured by the imaging device 3 as an input value and the actual leveling operation amount performed by the operator at that time as an output value, thereby generating a machine learning model in advance. Thereafter, in the image display method or system of the present invention, the image of the steel sheet S captured by the imaging device 3 in the imaging step (steps S2 to S5) is input to the trained machine learning model, and an appropriate operation amount for preventing tail end squeezing is output to the display device 5 as an output from the machine learning model. Subsequently, based on the displayed operation amount, for example, an operator adjusts the leveling of the mill stand 1 to be controlled using the control device 6. Note that in operation pattern 2, the operation amount may be output directly to the control device 6, thereby performing direct rolling control without the intervention of an operator.

[0072] <Operation Pattern 3> In operation pattern 3, for example, in operation pattern 1, a machine learning model is generated so that one or more of the rolling parameters and steel sheet specification data (e.g., thickness, width, length, weight, material, temperature, etc. of the steel sheet) during rolling can be additionally input as input values ​​to the machine learning model. In the image display method or system according to the present invention, in addition to the image of the steel sheet S captured by the imaging device 3 in the imaging step (steps S2 to S5), one or more of the rolling parameters and steel sheet specification data (e.g., thickness, width, length, weight, material, temperature, etc. of the steel sheet) during rolling acquired from a predetermined memory area are input as input values ​​to the trained machine learning model, and information regarding the occurrence or non-occurrence of tail end reduction is displayed on the display device 5 as output from the machine learning model. Subsequently, based on the displayed information, for example, an operator uses the control device 6 to adjust the leveling of the mill stand 1 to be controlled.

[0073] Furthermore, in operation pattern 3, for example, in operation pattern 2, a machine learning model is generated so that one or more of the rolling parameters and steel sheet specification data (e.g., thickness, width, length, weight, material, temperature, etc.) during rolling can be additionally input as input values ​​to the machine learning model. In the image display method or system according to the present invention, in addition to the image of the steel sheet S captured by the imaging device 3 in the imaging step (steps S2 to S5), one or more of the rolling parameters and steel sheet specification data (e.g., thickness, width, length, weight, material, temperature, etc.) during rolling acquired from a predetermined storage area are input as input values ​​to the trained machine learning model, and appropriate manipulated variables are displayed on the display device 5 as outputs from the machine learning model. Subsequently, based on the displayed manipulated variables, for example, an operator uses the control device 6 to adjust the leveling of the mill stand 1 to be controlled. Alternatively, the manipulated variables may be output directly to the control device 6, thereby directly controlling the rolling without the intervention of an operator.

[0074] <How to collect teacher data> For example, image data or an edge elongation index (e.g., steepness or elongation rate) created by image processing of the image data is collected from the image processing device 4. Furthermore, operating conditions including one or more of rolling parameters during rolling and steel sheet specification data (e.g., thickness, width, length, weight, material, temperature, etc. of the steel sheet) can be collected from a process computer, which is a system that manages information required for operation (e.g., steel sheet data and control data).

[0075] Furthermore, the actual results of the leveling operation amount may be collected from the control device 6, or may be acquired from the process computer if the process computer holds such results. Furthermore, the presence or absence of tail end throttling may be acquired from the process computer if the process computer holds such results. Furthermore, the presence or absence of tail end throttling may be acquired from a storage area in which the operator inputs the results of whether tail end throttling has occurred.

[0076] <How to generate a machine learning model> A trained machine learning model is generated based on the training data collected as described above. By training a large amount of training data, the relationship between the image data or edge elongation index obtained from the image according to the present invention and the occurrence of tail end squeezing becomes clear, which is expected to lead to the output of patterns of tail end squeezing and operation amounts to prevent its occurrence.

[0077] For example, a machine learning model can be generated by a decision tree analysis model using image data of the steel plate S, the specifications and operation amounts of the steel plate, rolling parameters, the presence or absence of tail end reduction, and the actual operation amounts as training data. In this case, by performing learning using the presence or absence of tail end reduction and / or the actual operation amounts as dependent variables (output values) and other data as independent variables (input values), it is possible to classify patterns in which tail end reduction occurs. Furthermore, by using the machine learning model generated by the above method, it is possible to obtain, as output, the probability of tail end reduction occurring in a specific image pattern or rolling pattern and the operation amounts to prevent it.

[0078] (Steel plate manufacturing method) The method for controlling rolling of a steel sheet according to the embodiment can also be applied to a method for manufacturing a steel sheet. In this case, in the method for manufacturing a steel sheet, the steel sheet S is manufactured while controlling the threading of the steel sheet S by the method for controlling rolling of a steel sheet. That is, in the method for manufacturing a steel sheet, the control device 6 adjusts the leveling of the mill stand 1 to be controlled, thereby manufacturing a steel sheet S without tail end reduction.

[0079] (Quality control method for steel sheets) The method for controlling rolling of a steel sheet according to the embodiment can also be applied to a method for controlling the quality of a steel sheet. In this case, the quality control method for a steel sheet controls the quality of the steel sheet S while controlling the threading of the steel sheet S by the method for controlling rolling of a steel sheet. That is, in the quality control method for a steel sheet, the control device 6 adjusts the leveling of the mill stand 1 to be controlled, thereby controlling the quality of the steel sheet S so that tail-end squeezing does not occur.

[0080] In the steel plate image display method, steel plate rolling control method, steel plate manufacturing method, steel plate quality control method, steel plate image display system, steel plate rolling equipment, and steel plate manufacturing equipment according to the above-described embodiments, images of the moment when the leading edge of the steel plate S passes from the controlled mill stand 1 to the next mill stand 2 are continuously acquired and displayed to an operator, for example, to visualize the shape of the leading edge of the steel plate S. Furthermore, by making appropriate leveling adjustments based on the acquired images of the leading edge of the steel plate S until the tail end of the steel plate S passes through the controlled mill stand 1, it is possible to reduce the occurrence of tail end reduction.

[0081] That is, in the steel plate image display method, steel plate rolling control method, steel plate manufacturing method, steel plate quality control method, steel plate image display system, steel plate rolling equipment, and steel plate manufacturing equipment according to the embodiments, the moment when the leading edge of the steel plate S passes between mill stands is imaged by the imaging device 3 from the side in the conveying direction p of the steel plate S, and the image is displayed at any timing. This makes it possible to grasp the shape of the leading edge of the steel plate S before rolling by the next mill stand 2. Then, by adjusting the leveling based on this shape tendency of the steel plate S before rolling, it is possible to reduce the occurrence of tail end squeezing.

[0082] The image display method for a steel plate, the rolling control method for a steel plate, the manufacturing method for a steel plate, the quality control method for a steel plate, the image display system for a steel plate, the rolling equipment for a steel plate, and the manufacturing equipment for a steel plate according to the present invention have been specifically described above using the preferred embodiment and examples for carrying out the invention, but the gist of the present invention is not limited to these descriptions and must be broadly interpreted based on the claims. Furthermore, it goes without saying that various changes, modifications, etc. based on these descriptions are also included in the gist of the present invention. [Explanation of symbols]

[0083] 1 Mill stand to be controlled Secondary Mill Stand 3. Imaging device 4. Image processing device 5 Display device 6. Control device A, B, C steel plate inspection areas S steel plate p conveying direction alpha plane θ Acceptance angle

Claims

1. An image display method for displaying an image of a steel plate being rolled by a tandem rolling mill having a plurality of mill stands, comprising: an imaging step in which an imaging device having an imaging frame rate of 90 frames per second or more is installed outside the pass line of the steel sheet and receives thermal radiation light emitted from the steel sheet, thereby imaging the leading edge of the steel sheet from when it leaves the mill stand to be controlled and is bitten into the next mill stand until tension control is started; a display step of reproducing the images obtained in the imaging step in time series by a display device; A method for displaying an image of a steel plate, comprising:

2. When a reference plane of the surface of the steel plate is defined as a plane α, an angle θ formed between the plane α and the optical axis of the imaging device is set in a range of 0° to 45°, 2. The method for displaying an image of a steel plate according to claim 1, wherein an angle φ formed between an orthogonal projection of the optical axis of the imaging device onto the plane α and a conveying direction p of the steel plate is set in a range of 70° to 110°.

3. The method for displaying an image of a steel plate according to claim 1, wherein a plurality of the imaging devices are installed so as to capture images of the steel plate between a plurality of consecutive mill stands.

4. A method for controlling rolling of a steel plate, comprising a control step of controlling a mill stand to be controlled by a control device while the steel plate is being rolled in the mill stand to be controlled, using an image obtained by the method for displaying an image of a steel plate according to any one of claims 1 to 3.

5. A method for manufacturing a steel plate, comprising: manufacturing the steel plate while controlling the threading of the steel plate by the method for controlling rolling of the steel plate according to claim 4.

6. A method for controlling the quality of a steel sheet, comprising controlling the quality of the steel sheet while controlling the threading of the steel sheet by the method for controlling the rolling of a steel sheet according to claim 4.

7. An image display system for displaying an image of a steel plate being rolled by a tandem rolling mill having a plurality of mill stands, an imaging device that is installed outside the pass line of the steel sheet, has an imaging frame rate of 90 frames per second or more, and receives thermal radiation light emitted from the steel sheet to capture images of the leading edge of the steel sheet from when it passes through a mill stand to be controlled and is bitten into the next mill stand until tension control is started; a display device that plays back images obtained by the imaging device in time series; A steel plate image display system comprising:

8. A steel plate rolling facility comprising the steel plate image display system according to claim 7.

9. A steel plate manufacturing facility comprising the steel plate image display system according to claim 7.

Images