Rolled material meandering amount prediction device, meandering amount control device, meandering amount prediction method, meandering amount control method, and metal strip manufacturing method

Abstract

To provide a meandering amount predicting device and a meandering amount predicting method which can predict a meandering amount of a tail edge part of a rolled material.SOLUTION: A meandering amount predicting device for a rolled material according to the present invention, which predicts a meandering amount of a tail edge part of a rolled material in a rolling stand constituting a hot-finish rolling machine, comprises: an inlet-side wedge identifying part that identifies an amount of a wedge at a tip part of the rolled material at the inlet side of the rolling stand; an inlet-side camber identifying part that identifies an amount of a camber at the tip part of the rolled material at the inlet side of the rolling stand; an outlet-side camber identifying part that identifies an amount of a camber at the tip part of the rolled material at an outlet side of the rolling stand; and a tail edge meandering amount predicting part that predicts a meandering amount of the tail edge part of the rolled material in the rolling stand, using the amount of the wedge at the tip part of the rolled material identified by the inlet-side wedge identifying part, the amount of the camber at the tip part of the rolled material identified by the inlet-side camber identifying part and the amount of the camber at the tip part of the rolled material identified by the outlet-side camber identifying part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a device for predicting the amount of meandering of a rolled material, a device for controlling the amount of meandering, a method for predicting the amount of meandering, a method for controlling the amount of meandering, and a method for manufacturing a metal strip. [Background technology]

[0002] In hot finishing mills, the material to be rolled does not remain stable in the widthwise center of the rolls, and as rolling progresses, meandering can become a problem. This movement can cause the material to move toward the widthwise ends of the rolls. When meandering occurs, the material may collide with the side guides as the tail end of the material exits the rolling stand, resulting in an operational problem known as "squeezing." This causes the material to collide with the side guides, causing the widthwise ends of the material to be bent and rolled. When squeezing occurs, roll defects occur in the rolls, resulting in problems such as a decrease in operation rate due to sudden roll replacement, a deterioration in roll consumption rate, and a decrease in yield due to the formation of semi-finished material.

[0003] To address this issue, it is common to adjust the leveling of the rolling mill (the difference in the roll gap between the drive side and work side of the rolling mill) to control meandering of the rolled material. However, once meandering of the rolled material occurs, a difference in the rolling load (differential load) occurs between the drive side and work side of the rolling mill, resulting in a difference in the roll gap between the drive side and work side of the rolling rolls. This results in a difference in the amount of roll reduction of the rolled material between the drive side and work side, which increases the bending of the rolled material and further accelerates meandering. In other words, once meandering of the rolled material occurs, the amount of meandering of the rolled material becomes even greater, leading to squeezing. Against this background, a method has been proposed in which factors that may cause meandering of the rolled material are identified in advance and the leveling of the rolling mill is adjusted before rolling.

[0004] For example, Patent Document 1 describes a method for suppressing meandering of a rolled material in the early stage of rolling in a tandem rolling mill equipped with multiple rolling stands. Specifically, this method first detects the entry-side off-center amount of the rolled material in the first rolling stand, the delivery-side off-center amount of the rolled material in the final rolling stand, and the rolling load, differential load, and single-side reduction (leveling amount) in each rolling stand. Next, this method estimates the delivery-side off-center amount of the rolled material in each rolling stand based on the detected values. This method then calculates a single-side reduction correction amount (leveling correction amount) so that the estimated delivery-side off-center amount of the rolled material in each rolling stand becomes zero, and adjusts the leveling of each rolling stand according to the calculated single-side reduction correction amount before starting rolling of the next material.

[0005] Furthermore, Patent Document 2 describes a method for suppressing meandering of a rolled material in both cases where the rolled material is off-center overall but not cambered, and where the rolled material is cambered. Specifically, this method first measures the amount of off-center at the tip of the rolled material at the entry side of the first rolling stand of the finishing mill and the amount of camber (bending) at each longitudinal position of the rolled material after rough rolling. Next, this method sets the leveling of the first rolling stand based on the measured amount of off-center until the tip of the rolled material passes through the first rolling stand of the finishing mill. Then, this method adjusts the leveling of the first rolling stand according to the measured amount of camber after the tip of the rolled material has passed the first rolling stand. Furthermore, this method also adjusts the roll gap from the second rolling stand onwards of the finishing mill based on the rolling conditions and the difference in mill stiffness between the left and right sides of each rolling stand so that the roll gap is equal between the work side and the drive side. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 9-201613 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-157317 Summary of the Invention [Problem to be solved by the invention]

[0007] The method described in Patent Document 1 uses the entry-side off-center amount of the tip of the material being rolled in the first rolling stand of a tandem rolling mill and the exit-side off-center amount of the tip of the material being rolled in the final rolling stand to suppress the off-center amount of the next material being rolled. Therefore, if the rolling conditions, such as the material quality, thickness, and width, of the current and next rolled materials are the same, a certain degree of meandering suppression effect can be expected. However, if the rolling conditions of the current and next rolled materials are different, it may not be possible to suppress the off-center amount. Furthermore, it is difficult to suppress the off-center amount of the first rolled material after rearranging the roll rolls of a tandem rolling mill. On the other hand, the method described in Patent Document 2 can achieve a certain degree of effect when meandering of the rolled material occurring in the first rolling stand of the finishing mill is caused by the camber or off-center of the rolled material at the entry side of the finishing mill. However, sufficient effect cannot be obtained if the material being rolled has a wedge (deviation in thickness in the width direction) at the entrance of the finishing rolling mill or if the first rolling stand causes the material to meander.

[0008] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a device and method for predicting the meandering amount of a rolled material, which are capable of predicting the amount of meandering at the tail end of the rolled material. Another object of the present invention is to provide a device and method for controlling the meandering amount of a rolled material, which are capable of reducing the amount of meandering at the tail end of the rolled material. Still another object of the present invention is to provide a method for manufacturing a metal strip, which is capable of producing a metal strip with reduced camber (bending) at the tail end. [Means for solving the problem]

[0009] The meandering amount prediction device for rolled material according to the present invention is a device for predicting the amount of meandering of the tail end of the rolled material in a rolling stand that constitutes a hot finishing rolling mill, and comprises an entry wedge specifying unit that specifies the wedge amount of the tip end of the rolled material at the entry side of the rolling stand; an entry camber specifying unit that specifies the camber amount of the tip end of the rolled material at the entry side of the rolling stand; an exit camber specifying unit that specifies the camber amount of the tip end of the rolled material at the exit side of the rolling stand; and a tail end meandering amount prediction unit that predicts the amount of meandering of the tail end of the rolled material in the rolling stand using the wedge amount of the tip end of the rolled material specified by the entry wedge specifying unit, the camber amount of the tip end of the rolled material specified by the entry camber specifying unit, and the camber amount of the tip end of the rolled material specified by the exit camber specifying unit.

[0010] The device for controlling the amount of meandering of a rolled material according to the present invention comprises a leveling setting value calculation unit that calculates a leveling setting value of the rolling stand based on the amount of meandering of the tail end of the rolled material predicted by the device for predicting the amount of meandering of a rolled material according to the present invention, and a leveling setting unit that sets the leveling of the rolling stand based on the leveling setting value calculated by the leveling setting value calculation unit during rolling of the steady portion of the rolled material.

[0011] A method for predicting the amount of meandering of a rolled material according to the present invention is a method for predicting the amount of meandering of the tail end of the rolled material in a rolling stand that constitutes a hot finishing mill, and includes: an entry wedge specifying step for specifying a wedge amount of the tip end of the rolled material at the entry side of the rolling stand; an entry camber specifying step for specifying a camber amount of the tip end of the rolled material at the entry side of the rolling stand; an exit camber specifying step for specifying a camber amount of the tip end of the rolled material at the exit side of the rolling stand; and a tail end meandering amount prediction step for predicting the amount of meandering of the tail end of the rolled material in the rolling stand using the wedge amount of the tip end of the rolled material specified in the entry wedge specifying step, the camber amount of the tip end of the rolled material specified in the entry camber specifying step, and the camber amount of the tip end of the rolled material specified in the exit camber specifying step.

[0012] The tail end meandering amount prediction step preferably includes a step of predicting the amount of meandering of the tail end of the rolled material in the rolling stand using a tail end meandering amount prediction model learned by machine learning, which includes as inputs the wedge amount of the tip end of the rolled material identified in the entry wedge identification step, the camber amount of the tip end of the rolled material identified in the entry camber identification step, and the camber amount of the tip end of the rolled material identified in the exit camber identification step, and which outputs the amount of meandering of the tail end of the rolled material in the rolling stand.

[0013] The method for controlling the meandering amount of a material to be rolled according to the present invention includes a leveling setting value calculation step for calculating a leveling setting value of the rolling stand based on the meandering amount of the tail end of the material to be rolled predicted by the method for predicting the meandering amount of a material to be rolled according to the present invention, and a leveling setting step for setting the leveling of the rolling stand based on the leveling setting value calculated in the leveling setting value calculation step during rolling of the steady portion of the material to be rolled.

[0014] The method for manufacturing a metal strip according to the present invention includes a step of manufacturing a metal strip using the method for controlling the meandering amount of a rolled material according to the present invention. [Effects of the Invention]

[0015] The meandering amount prediction device and meandering amount prediction method for a rolled material according to the present invention can predict the meandering amount of the tail end of the rolled material. Also, the meandering amount control device and meandering amount control method for a rolled material according to the present invention can reduce the meandering amount of the tail end of the rolled material. Furthermore, the metal strip manufacturing method according to the present invention can manufacture a metal strip with reduced camber at the tail end. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of a hot rolling line including a hot finishing mill to which the present invention is applied. [Figure 2] FIG. 2 is a schematic diagram showing an example of the configuration of a hot finishing mill to which the present invention is applied. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of one rolling stand that constitutes a hot finishing mill. [Figure 4] FIG. 4 is a block diagram showing the configuration of a rolled material meandering amount prediction device according to one embodiment of the present invention. [Figure 5] FIG. 5 is a diagram for explaining the definition of the wedge amount. [Figure 6] FIG. 6 is a diagram for explaining the definition of the camber amount. [Figure 7] FIG. 7 is a diagram for explaining the definition of the amount of meandering. [Figure 8] FIG. 8 is a flowchart showing the flow of a method for predicting the meandering amount of a rolled material according to one embodiment of the present invention. [Figure 9] FIG. 9 is a block diagram showing the configuration of a device for controlling the amount of meandering of a material to be rolled, which is one embodiment of the present invention. [Figure 10] FIG. 10 is a flowchart showing the flow of a method for controlling the meandering amount of a rolled material according to one embodiment of the present invention. [Figure 11] FIG. 11 is a block diagram showing the configuration of a tail-end meandering amount prediction model generation unit according to one embodiment of the present invention. [Figure 12] FIG. 12 is a schematic diagram showing the configuration of a tail-tip meander amount prediction model using a neural network. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, with reference to the drawings, a rolled material meandering amount prediction device, meandering amount control device, meandering amount prediction method, meandering amount control method, and metal strip manufacturing method according to one embodiment of the present invention will be described in detail.

[0018] [Configuration of hot finishing rolling mill] First, with reference to Figs. 1 to 3, the configuration of a hot finishing mill (hereinafter sometimes simply referred to as a "finishing mill") to which the present invention is applied will be described.

[0019] FIG. 1 is a schematic diagram showing an example of the configuration of a hot rolling line including a hot finishing mill to which the present invention is applied. As shown in FIG. 1, the hot rolling line 1 includes a heating furnace 2, a descaling unit 3, a width reduction press unit 4, a roughing mill 5, a finishing mill 6, a cooling unit 7, and a coiler (winder) 8. A cast slab (not shown) is charged into the heating furnace 2, heated to a predetermined set temperature, and extracted from the heating furnace 2 as a hot slab. The hot slab extracted from the heating furnace 2 has primary scale formed on its surface removed by the descaling unit 3, and then its width is reduced to a predetermined set width by the width reduction press unit 4. The reduced width slab is then rolled to a predetermined thickness in the roughing mill 5 to form a rough bar (roughly rolled material), which is then transported to the finishing mill 6. In the finishing mill 6, the rough bar, which is the material to be rolled according to the present invention, is rolled to a product thickness by a continuous rolling mill equipped with five to seven rolling stands. Downstream of the finishing mill 6, a cooling device 7 is provided in a facility called a run-out table, and the material to be rolled is cooled to a predetermined temperature and then wound into a coil by a coiler 8.

[0020] FIG. 2 is a schematic diagram showing an example of the configuration of a hot finishing rolling mill to which the present invention is applied. As shown in FIG. 2, the finishing rolling mill 6 is equipped with seven rolling stands F1 to F7 (sometimes simply referred to as rolling mills). An entry transport roll 10 is arranged on the entry side of the finishing rolling mill 6 (upstream side in the direction of travel of the material S to be rolled), and a crop shear (not shown) is arranged further upstream of the entry transport roll 10 to cut and remove crops (irregularly shaped portions at the leading and trailing ends) of the material S to be rolled. The material S from which the crops at the leading and trailing ends have been removed by the crop shear is passed through the rolling stands F1 to F7 in sequence, and when the leading end of the material S passes through the final rolling stand (final rolling stand) F7, "steady-state rolling" is achieved in which the material S is being rolled in all of the rolling stands F1 to F7. The tail end of the rolled material S then passes through the rolling stands F1 to F7 in sequence, and the finish rolling of the rolled material S is completed when the tail end of the rolled material S passes through the final rolling stand F7. In this case, the process in which the front end of the rolled material S passes through the rolling stands F1 to F7 in sequence is called "threading," and the process in which the tail end of the rolled material S passes through the rolling stands F1 to F7 in sequence is called "tail removal." The present invention predicts and reduces the amount of meandering (off-center amount) of the rolled material S during the tail removal process in which the tail end of the rolled material S passes through each of the rolling stands F1 to F7 in sequence.

[0021] An exit transport roll 11 is disposed on the exit side of the finishing rolling mill 6 (downstream in the direction of travel of the rolled material S), and together with the entry transport roll 10, a pass line PL is set, which is the reference position in the height direction along which the rolled material S is transported. The pass line PL also serves as the reference position in the height direction when the rolled material S is rolled in each of the rolling stands F1 to F7. Meanwhile, an interstand looper 12 is disposed between the rolling stands of the finishing rolling mill 6 (between adjacent rolling stands). The interstand looper 12 is a device for adjusting the balance between the speed of the rolled material S being discharged from the upstream rolling stand and the speed of the rolled material S being charged into the downstream rolling stand. The height of the tip of the interstand looper 12 (looper roll) relative to the pass line PL is variable, and control is performed so that the tension applied to the rolled material S is maintained within a predetermined range during steady-state rolling of the rolled material S. However, during the process of threading the rolled material S, the looper rolls are already lowered to the height of the pass line PL, and control of the inter-stand looper 12 (looper control) is performed after the leading end of the rolled material S reaches the downstream rolling stand. Also, during the process of the rolled material S passing through the tail end of the rolled material S, looper control is performed so that the looper rolls are lowered to the height of the pass line PL at the time the tail end of the rolled material S passes through the upstream rolling stand.

[0022] In this embodiment, for each of the rolling stands F1 to F7, the upstream side in the traveling direction of the rolled material S is referred to as the "entrance side," and the downstream side in the traveling direction of the rolled material S is referred to as the "exit side." In this case, the entry side of rolling stand F3 refers to the range between rolling stand F2 and rolling stand F3, which are the rolling stands located upstream of it, and the exit side of rolling stand F3 refers to the range between rolling stand F4 and rolling stand F3, which are the rolling stands located downstream of it. Note that the entry side of rolling stand F1, which is the first rolling stand, refers to the range between rolling stand F1 and the crop shear located upstream of it. On the other hand, the exit side of rolling stand F7, which is the final rolling stand, refers to the range between rolling stand F7 and the run-out table located downstream of it.

[0023] The finishing rolling mill 6 is equipped with a programmable logic controller (PLC) 90 for controlling each device constituting the finishing rolling mill 6, and a control computer (process computer) 91 for giving control commands to the control controller 90. The hot rolling line 1 is also equipped with a host computer 92 for giving production instructions to each piece of equipment including the finishing rolling mill 6. Rolling control in the finishing rolling mill 6 is carried out by the control computer 91 setting operating conditions for the material S to be rolled based on the host computer 92 or production instructions from the host computer 92. The control controller 90 also has the function of collecting information obtained from various sensors (thickness gauge, width gauge, thermometer, etc.) installed in the finishing rolling mill 6 at a predetermined sampling period and outputting the information to the control computer 91.

[0024] FIG. 3 illustrates an example of the configuration of one rolling stand that constitutes a finishing rolling mill 6. As shown in FIGS. 3(a) and 3(b), the rolling stand is equipped with a pair of work rolls 61a, 61b arranged vertically across the pass line PL. The work rolls 61a, 61b are supported by backup rolls 62a, 62b, respectively. One end of each of the work rolls 61a, 61b is connected to a drive motor via a coupling or a reducer. The drive motor rotates the work rolls 61a, 61b. In this case, the side of the rolling stand on which the drive motor is located is sometimes called the drive side (DS), and the opposite side is sometimes called the work side (WS).

[0025] The backup rolls 62a, 62b are supported by bearing housings (backup roll chocks) 63a, 63b, which are arranged at the axial ends of the backup rolls 62a, 62b, respectively. The rolling load applied to the rolled material S is transmitted to housings 64a, 64b via the backup roll chocks 63a, 63b. Load cells 65a, 65b, which serve as load detectors, are arranged between the housings 64a, 64b and the backup roll chocks 63a, 63b, making it possible to measure the rolling load applied to the rolled material S. In this case, the sum of the measurement values ​​measured by the load cell 65a and the load cell 65b is sometimes called the rolling load or sum load, and the difference between the measurement values ​​measured by the load cell 65a and the load cell 65b is sometimes called the differential load.

[0026] Screw down devices 66a, 66b are arranged on the work side and drive side of the rolling stand. The screw down devices 66a, 66b adjust the gap (also called the roll gap or roll opening) between the work rolls 61a and 61b by vertically displacing the backup roll chocks 63a, 63b, respectively. The vertical positions of the backup roll chocks 63a, 63b are usually configured so that they can be measured by a displacement gauge (not shown). Because it is difficult to actually measure the gap between the work rolls 61a and 61b, the roll opening is conventionally set by the vertical positions of the backup roll chocks 63a, 63b.

[0027] The screw down devices 66a, 66b are equipped with electric or hydraulic screw down mechanisms. The hydraulic screw down mechanism (also called hydraulic screw down) displaces the backup roll chocks 63a, 63b in the up and down direction by controlling the hydraulic pressure of a hydraulic cylinder. The electric screw down device (also called electric screw down) displaces the backup roll chocks 63a, 63b in the up and down direction by rotating an electric motor for the screw down device and moving a screw down screw up and down via a gear. The screw down devices 66a, 66b are not limited to a type that displaces the backup roll 62a in the up and down direction from the upper part of the housing 64a, 64b, but may be a type that displaces the backup roll 62b in the up and down direction from the lower part of the housing 64a, 64b.

[0028] The screw down devices 66a, 66b usually set the vertical positions of the backup roll chocks 63a, 63b so that the gap between the work rolls 61a and 61b is the same on the work side and the drive side. However, the vertical positions of the backup roll chocks 63a, 63b may be set differently. Setting the vertical positions of the backup roll chocks 63a, 63b to be different is called leveling, and the difference in the vertical positions of the backup roll chock 63a on the work side and the backup roll chock 63b on the drive side is sometimes called the leveling amount. Leveling is intended to create a difference in the roll gap between the work side and the drive side work rolls, but in reality, it is performed by creating a difference in the vertical positions of the backup roll chocks 63a, 63b, as described above.

[0029] [Meandering amount prediction device] Next, the configuration of a device for predicting the meandering amount of a rolled material according to one embodiment of the present invention will be described with reference to FIGS.

[0030] Fig. 4 is a block diagram showing the configuration of a rolled material meandering amount prediction device according to one embodiment of the present invention. As shown in Fig. 4, a rolled material meandering amount prediction device 20 according to one embodiment of the present invention includes an entry-side wedge specifying unit 21, an entry-side camber specifying unit 22, an exit-side camber specifying unit 23, and a tail-end meandering amount prediction unit 24.

[0031] The entry wedge specifying unit 21 specifies the wedge amount of the tip of the rolled material S at the entry side of the rolling stand F constituting the finishing rolling mill 6. The wedge of the rolled material S refers to a state in which thickness deviation occurs in the width direction of the rolled material S, and the thickness deviation in the width direction of the rolled material S is called the wedge amount. Specifically, the wedge amount is defined as the difference between the thickness h1 of the rolled material S at a predetermined distance We from the width direction end of the work side and the thickness h2 of the rolled material S at the distance We from the width direction end of the drive side in the cross-sectional shape of the rolled material S shown in FIG. 5. In this case, a positive wedge amount may be defined as a case in which the thickness h1 at the width direction end of the work side is greater than the thickness h2 at the width direction end of the drive side, and a negative wedge amount may be defined as a case in which the thickness h1 at the width direction end of the work side is smaller than the thickness h2 at the width direction end of the drive side. The distance We from the width direction end, which serves as a reference for the wedge amount, is set, for example, in the range of 15 to 200 mm.

[0032] Returning to FIG. 4, the entry wedge identifying unit 21 may be configured to install a wedge meter 31 on the entry side of the rolling stand F and identify the wedge amount at the leading end of the rolled material S based on measurements by the wedge meter 31. The wedge meter 31 may be, for example, a plurality of thickness gauges using X-rays or gamma rays, installed in the width direction of the rolled material S, and measure the thickness h1 of the rolled material S at the width direction end of the work side and the thickness h2 of the rolled material S at the width direction end of the drive side. The wedge meter 31 may also be configured to scan the thickness gauge in the width direction of the rolled material S to measure the width direction thickness distribution of the rolled material S, and calculate the wedge amount from the measured thickness distribution. Furthermore, laser scanning distance meters may be installed on the front and back sides of the rolled material S, and the thickness of the rolled material S may be calculated from the difference between the distance information obtained on the front side and the distance information obtained on the back side using distance information measured by the distance meters at each position in the width direction of the rolled material S.

[0033] In this embodiment, the entry wedge specifying unit 21 specifies the wedge amount obtained at the leading end of the rolled material S. Here, the "leading end" of the rolled material S in this embodiment refers to the range of the rolled material S that exists between rolling stands from when the rolled material S passes through a rolling stand until it is caught in the next rolling stand during the sheet threading process of the finishing rolling mill 6. In this case, the range of the rolled material S that exists between rolling stands after the leading end of the rolled material S (the foremost part of the rolled material S) passes through rolling stand F-1 on the upstream side of rolling stand F and reaches the next rolling stand F is referred to as the leading end of the rolled material S on the entry side of rolling stand F. Also, the range of the rolled material S that exists between rolling stands after the leading end of the rolled material S passes through rolling stand F and reaches the next rolling stand F+1 is referred to as the leading end of the rolled material S on the exit side of rolling stand F.

[0034] On the other hand, in this embodiment, the "tail end" of the rolled material S refers to the range of the rolled material S that exists between rolling stands during the tail end process of the finishing rolling mill 6, from when the tail end (the tailmost part of the rolled material S) of the rolled material S leaves one rolling stand until the tail end of the rolled material S leaves the next rolling stand. In this case, the range of the rolled material S that exists between rolling stands from when the tail end of the rolled material S leaves the upstream rolling stand F-1 with respect to rolling stand F until it reaches rolling stand F is referred to as the tail end of the rolled material S on the entry side of rolling stand F. Also, the range of the rolled material S that exists between rolling stands from when the tail end of the rolled material S leaves rolling stand F until it leaves the downstream rolling stand F+1 is referred to as the tail end of the rolled material S on the exit side of rolling stand F.

[0035] The entry camber specifying unit 22 specifies the amount of camber at the tip of the material S to be rolled on the entry side of the rolling stand F. The exit camber specifying unit 23 specifies the amount of camber at the tip of the material S to be rolled on the exit side of the rolling stand F. The amount of camber (amount of curvature) at the tip of the material S to be rolled refers to the difference between the widthwise center position at the tip of the material S to be rolled and the widthwise center position at a position a predetermined distance away from the tip of the material S to be rolled. The amount of camber of the material S to be rolled is sometimes conventionally called the amount of lateral curvature.

[0036] As shown in Figure 6, the camber amount Cam at the tip of the rolled material S is expressed as the difference between the distance y1 and the distance y2, where y1 is the distance between the widthwise center position P0 of the rolling stand F and the widthwise center position of the tip of the rolled material S, and y2 is the distance between the widthwise center position P0 of the rolling stand F and the widthwise center position of the rolled material S at a position distance z from the tip of the rolled material S. In this case, positive and negative camber amounts may be defined depending on the direction of the bend of the rolled material S, with a positive camber amount being defined when the rolled material S is bent toward the work side and a negative camber amount being defined when the rolled material S is bent toward the drive side. The distance z from the tip of the rolled material S, which serves as the basis for the camber amount, may be set arbitrarily, with the distance between the rolling stands as an upper limit. Specifically, the distance z is set in the range of 500 to 6000 mm.

[0037] Returning to Figure 4, the entry camber specifying unit 22 and the exit camber specifying unit 23 can be measuring devices capable of measuring the leading edge of the rolled material S and the widthwise position of the rolled material S at a position a distance z from the leading edge. The entry camber specifying unit 22 and the exit camber specifying unit 23 can, for example, be provided with an entry camera 32 on the entry side of the rolling stand F that images the leading edge of the rolled material S from the top or bottom, and an exit camera 33 on the exit side of the rolling stand F that images the leading edge of the rolled material S from the top or bottom, and can identify the camber amount of the rolled material S by applying image processing to the images of the leading edge of the rolled material S taken by the entry camera 32 and the exit camera 33. In this case, it is advisable to position the entry camera 32 so that it can image the surface of the leading edge of the rolled material S from above between the rolling stands on the entry side of the rolling stand F. The exit camera 33 is preferably positioned so as to be able to photograph the surface of the leading edge of the rolled material S from above between the rolling stands on the exit side of the rolling stand F. This allows the entry camera 32 and the exit camera 33 to acquire an image of the leading edge of the rolled material S as shown in Figure 6.

[0038] Returning to Figure 4, the entry camber specifying unit 22 and the exit camber specifying unit 23 extract the contour shape of the rolled material S by image processing from the images of the leading end of the rolled material S acquired by the entry camera 32 and the exit camera 33, respectively, and specify the amount of camber of the rolled material S based on the extracted contour shape of the rolled material S. In this case, in order to convert the dimensions of the images acquired by the cameras to an actual scale, the correspondence between the distance between pixels and the actual distance is specified in advance.

[0039] The timing at which the wedge amount specified by the entry wedge specifying unit 21, the camber amount specified by the entry camber specifying unit 22, and the camber amount specified by the delivery camber specifying unit 23 are acquired differs depending on the locations at which the respective measuring instruments and imaging devices are installed. In this case, the control controller 90 constantly tracks the leading edge of the rolled material S in order to control the threading process of the rolled material S, so it is advisable to use the tracking information generated by the control controller 90 to adjust the timing at which the wedge amount of the rolled material S is measured by the wedge meter 31 and the timing at which the entry camera 32 and the delivery camera 33 capture images of the rolled material S.

[0040] The tail end meandering amount prediction unit 24 predicts the amount of meandering of the tail end of the rolled material S in the rolling stand F using the wedge amount specified by the entry wedge specifying unit 21, the camber amount specified by the entry camber specifying unit 22, and the camber amount specified by the delivery camber specifying unit 23. Meandering of the tail end of the rolled material S refers to the deviation of the widthwise center position of the rolled material S from the widthwise center position of the rolling stand F when the tail end of the rolled material S passes through the rolling stand F (also called off-center), and the amount of meandering means the amount of deviation (also called off-center amount). As shown in Figure 7(a), the amount of meandering of the tail end of the rolled material S is the difference y c The meandering amount of the tail end of the rolled material can be defined as follows: As shown in Fig. 7(b), the meandering amount of the tail end of the rolled material is determined by the distance z c The difference y between the widthwise center position of the tail end of the rolled material S and the widthwise center position P0 of the rolling stand F at a distance c Both of these are indicators that represent the meandering behavior of the tail end of the rolled material S. In this case, the distance z c can be set arbitrarily with the distance between the rolling stands as the upper limit. For example, the distance z cThe distance z in Fig. 7(b) may be set in the range of 0 to 6000 mm. As with the camber amount, the direction of the meandering may be defined as positive or negative depending on the direction in which the tail end of the material S is shifted, with a positive meandering amount being defined when the material S is shifted to the work side and a negative meandering amount being defined when the material S is shifted to the drive side. c The case where is set to zero corresponds to the state shown in FIG. 7(a).

[0041] The meandering of the rolled material S occurs when there is a difference in the amount or reduction rate of the rolled material S between the drive side and the work side, resulting in a distribution of the progressing speed in the width direction of the rolled material S. In particular, when the tail end of the rolled material S passes through rolling stand F, the rolled material S is constrained by the work rolls in the downstream rolling stand F+1, whereas the tail end of the rolled material S passes through the upstream rolling stand F-1 and is not constrained in its displacement in the width direction. For this reason, the tail end of the rolled material S passing through rolling stand F is more susceptible to meandering than in the steady state. As a result, meandering of the tail end of the rolled material S occurs at the entry side of rolling stand F, where the tail end is about to pass. The difference in the amount or rate of reduction between the drive side and the work side of the rolled material S can be caused by improper leveling of the rolling stand, or by the presence of a wedge in the rolled material S even if the leveling is generally correct, resulting in a difference in reduction between the work side and the drive side.

[0042] The tail end meandering amount prediction unit 24 estimates the actual leveling value of the rolling stand F based on the wedge at the front end of the rolled material S and the camber amounts at the entry and exit sides of the rolling stand F (leveling estimation step).The tail end meandering amount prediction unit 24 then predicts the amount of meandering of the tail end portion that occurs when the rolled material S bottoms out, if the estimated actual leveling value is maintained until the steady rolling and bottoming out process of the rolled material S (meandering amount prediction step).

[0043] As described above, rolling stand leveling refers to imparting a difference in roll gap between the work-side and drive-side work rolls. In practice, however, it is set by imparting a difference in the vertical positions of the backup roll chocks 63a, 63b on the work side and drive side (command leveling). However, due to the influence of thermal expansion and wear of the backup rolls 62a, 62b and work rolls 61a, 61b that constitute the rolling stand, the command leveling set by the screw down devices 66a, 66b does not necessarily coincide with the difference in the roll gap between the work rolls 61a, 61b on the work side and drive side. In this embodiment, the tail end meandering amount prediction unit 24 estimates the actual value of the difference in the roll gap between the work rolls 61a, 61b on the work side and drive side during the threading process of the leading edge of the rolled material S, and calculates the estimated actual value of leveling as the estimated leveling value. Then, the tail end meandering amount predicting unit 24 predicts the amount of meandering at the tail end of the material S to be rolled using the calculated estimated leveling value.

[0044] The leveling estimation value S estimated by the leveling estimation step d is the wedge amount H specified by the inlet wedge specifying unit 21 d (mm), the camber amount C determined by the entry camber determination unit 22 i (mm), and the camber amount C determined by the exit camber determination unit 23 o Using the distance (mm), it can be calculated using the function f shown in the following formula (1).

[0045]

number

[0046] Here, H is the thickness (mm) of the rolled material S at the entry side of the rolling stand F, h is the thickness (mm) of the rolled material S at the exit side of the rolling stand F, z is the distance (mm) from the tip of the rolled material S to determine the amount of camber, and K pis the parallel rigidity (kN / mm) of the rolling stand F, M is the plasticity coefficient (kN / mm), P is the rolling load (kN), λ is the elongation rate of the material S to be rolled by the rolling stand F (the elongation rate of the material length on the outlet side relative to the material length on the inlet side), b is the width of the material S to be rolled (mm), and L is the distance between the screw down devices 66a and 66b that screw down the backup roll chocks 63a and 63b on the work side and drive side (see Figure 3).

[0047] Parallel stiffness K p is an index showing how easily the work rolls 61a and 61b can be maintained in parallel when a differential load occurs between the work rolls 61a and 61b, and in the case of a four-high rolling mill, for example, it can be calculated by the following formula (2).

[0048]

number

[0049] where K is the Mill constant (kN / mm), k r is the spring constant (kN / mm) that represents the flattening deformation between the work roll and the backup roll, k s is the spring constant (kN / mm) that represents the flattening deformation of the work roll that occurs between the work roll and the rolled material S, L b is the barrel length of the work roll (m).

[0050] The plasticity coefficient M is an index that indicates the change in rolling load relative to the change in thickness of the rolled material S, and can be calculated by the following formula (3).

[0051]

number

[0052] In addition, the parallel plastic coefficient M is used as an index that represents the change in differential load relative to the change in the wedge amount at the entry side and the exit side of rolling stand F. p can be defined as the following equation (4).

[0053]

number

[0054] Here, the above function formula f will be specifically derived. For example, if it is assumed that the curvature (camber) of the tip of the rolled material S can be approximated by a parabola (quadratic equation) along the longitudinal direction of the rolled material S, and the distribution of the rolling load along the width direction of the rolled material S can be approximated by a straight line, the estimated leveling value S d can be calculated using the following formula (5).

[0055]

number

[0056] Here, a0, a1, and a2 are parameters that represent the shape of the camber when the camber (curvature) at the front end of the rolled material S is approximated by a parabola (quadratic equation) along the longitudinal direction of the rolled material S. Specifically, a0, a1, and a2 are determined by the relationship shown in the following equation (6) using the distances y1 and y2 shown in FIG.

[0057]

number

[0058] On the other hand, using numerical analysis methods such as the finite element method, the wedge amount H d , camber amount C i , and camber amount C o and the estimated leveling value S of rolling stand F. d Regarding the relationship between the parameters, multiple calculations may be performed by changing each parameter. Then, based on the results of the numerical calculations, the input variables are calculated by changing the wedge amount H d , camber amount C i , and camber amount C o The output variable is the estimated leveling value S of rolling stand F. d The regression equation is calculated, and the estimated leveling value S of the rolling stand F is calculated using the calculated regression equation. dIn this case, numerical analysis may be performed by changing rolling conditions such as the thickness H of the rolled material S at the entry side of the rolling stand F, the thickness h of the rolled material S at the exit side of the rolling stand F, the deformation resistance of the rolled material S, and the friction coefficient in the rolling stand F, and these may be included as input variables in the regression equation.

[0059] In this way, based on the information acquired during the threading process of the leading end of the rolled material S, the actual leveling value of the rolling stand F (estimated leveling value S d ) is estimated.

[0060] Next, the tail end meandering amount prediction unit 24 calculates the estimated leveling value S d The amount of meandering of the tail end of the rolled material S is estimated when the leveling is maintained until the tail end of the rolled material S is released. Specifically, the estimated leveling value S d is maintained during the tailing out process, and the wedge amount H d Assuming that the wedge amount h of the rolled material S at the exit side of the rolling stand F is the same at the head and tail ends of the rolled material S, d can be calculated using the following formula (7).

[0061]

number

[0062] The wedge amount h of the material S to be rolled at the delivery side of the rolling stand F is calculated in this way. d is used to calculate the wedge ratio change of the rolled material S that occurs in the rolling stand F. The wedge ratio change is an index that represents the change in the wedge amount of the rolled material S at the entry side and exit side of the rolling stand F. Specifically, the wedge ratio Ψ1 of the rolled material S at the entry side of the rolling stand F and the wedge ratio Ψ2 of the rolled material S at the exit side of the rolling stand are defined by the following formula (8), and the wedge ratio change ΔΨ is defined by the following formula (9).

[0063]

number

[0064]

number

[0065] From these, the wedge ratio change ΔΨ at the tail end portion that occurs when the rolled material S tails out can be calculated using the following formula (10).

[0066]

number

[0067] The change in wedge ratio ΔΨ at the tail end of the rolled material S when it reaches the bottom represents the in-plane rotation behavior of the rolled material S. Therefore, the amount of meandering y c is calculated by the following formula (11): However, formula (11) is calculated on the assumption that the meandering of the tail end portion of the rolled material S that occurs when the material S tails out occurs after the tail end of the rolled material S leaves the upstream rolling stand F-1, and that the rolled material S is constrained at the delivery side of the downstream rolling stand.

[0068]

number

[0069] Note that d is the distance between the rolling stand F and the upstream stand F-1. In this case, as shown in FIG. 7(a), the distance z c If is set to zero, the meandering amount y c is expressed by the following equation (12).

[0070]

number

[0071] [Meandering amount prediction method] Next, a method for predicting the meandering amount of a rolled material according to one embodiment of the present invention will be described with reference to FIG.

[0072] 8 is a flowchart showing the flow of a method for predicting the meandering amount of a rolled material according to one embodiment of the present invention. As shown in FIG. 8, in the method for predicting the meandering amount of a rolled material according to one embodiment of the present invention, first, an entry wedge specifying unit 21 determines the wedge amount H of the leading end of the rolled material S obtained at the entry side of the rolling stand F. d Next, the entry camber determining unit 22 determines the camber amount C of the tip of the material S to be rolled, which is obtained at the entry side of the rolling stand F. i Next, the delivery camber specifying unit 23 determines the camber amount C of the tip of the rolled material S obtained at the delivery side of the rolling stand F. o Next, based on the information determined during the threading process of the leading end of the material S to be rolled, the tail end meandering amount predicting unit 24 determines the estimated leveling value S of the rolling stand F. d (Step S4). Then, the tail end meandering amount predicting unit 24 calculates the estimated leveling value S d Using the amount of meandering y at the tail end of the rolled material S c is predicted (step S5).

[0073] [Meandering amount control device] Next, with reference to FIG. 9, the configuration of a device for controlling the amount of meandering of a material to be rolled, which is one embodiment of the present invention, will be described.

[0074] Fig. 9 is a block diagram showing the configuration of a meandering amount control device for a rolled material according to one embodiment of the present invention. As shown in Fig. 9, a meandering amount control device 40 for a rolled material according to one embodiment of the present invention includes a leveling set value calculation unit 41 and a leveling setting unit 42. The leveling set value calculation unit 41 calculates a leveling set value for reducing meandering of the tail end of the rolled material S, based on the amount of meandering of the tail end of the rolled material S in the rolling stand F predicted by the meandering amount prediction device 20. The leveling setting unit 42 sets the leveling of the rolling stand F based on the leveling set value calculated by the leveling set value calculation unit 41, while the rolling stand F is rolling the steady portion of the rolled material S.

[0075] [Meandering amount control method] Next, a method for controlling the meandering amount of a rolled material according to one embodiment of the present invention will be described with reference to FIG.

[0076] FIG. 10 is a flowchart showing the flow of a method for controlling the meandering amount of a rolled material according to one embodiment of the present invention. In the method for controlling the meandering amount of a rolled material according to one embodiment of the present invention, a limit value (limit meandering amount) for the meandering amount of the tail end of the rolled material S is set in advance in the leveling set value calculation unit 41. As shown in FIG. 10, in the method for controlling the meandering amount of a rolled material according to one embodiment of the present invention, first, the meandering amount prediction device 20 predicts the meandering amount (predicted meandering amount) of the tail end of the rolled material S at the inlet side of the rolling stand F (step S11). Next, the leveling set value calculation unit 41 determines whether the predicted meandering amount is equal to or less than the limit meandering amount (step S12). If the result of the determination is that the predicted meandering amount is equal to or less than the limit meandering amount (step S12: Yes), the leveling set value calculation unit 41 determines a leveling set value so as to maintain the current leveling setting (initial leveling setting) (step S13). On the other hand, if the predicted meandering amount exceeds the limit meandering amount (step S12: No), the leveling set value calculation unit 41 determines the leveling set value as follows (step S14).

[0077] First, the leveling set value calculation unit 41 identifies whether the predicted meandering amount is positive or negative, and determines whether the tail end of the rolled material S will meander toward the work side of the rolling stand F or toward the drive side. Then, if it is predicted that the tail end of the rolled material S will meander toward the work side, the leveling set value calculation unit 41 sets a new leveling set value so that the roll gap on the work side is narrower than the command leveling that is set in advance. On the other hand, if it is predicted that the tail end of the rolled material S will meander toward the drive side, the leveling set value calculation unit 41 sets a new leveling set value so that the roll gap on the drive side is narrower than the command leveling. For example, if a meandering amount of 10 to 100 mm is predicted, the leveling set value calculation unit 41 may set a new leveling set value so that the command leveling is changed by approximately 0.01 to 0.1 mm.

[0078] On the other hand, the leveling set value calculation unit 41 may determine the leveling set value so that the predicted meandering amount is 0. In this case, the leveling set value calculation unit 41 determines the wedge ratio change (target wedge ratio change) ΔΨ of the rolled material S to make the predicted meandering amount 0. aim is calculated by the following formula (13). The leveling set value calculation unit 41 then calculates the leveling estimated value S from the condition that satisfies the following formula (14). d Leveling correction amount ΔS d Calculate.

[0079]

number

[0080]

number

[0081] As a result, the leveling set value calculation unit 41 calculates the leveling correction amount ΔS for making the predicted meandering amount zero. d Then, the leveling set value calculation unit 41 calculates the leveling correction amount ΔS for the current leveling set value (command leveling). dThe leveling amount obtained by adding the above is determined as the new leveling set value. The limit meandering amount is determined as the limit meandering amount at which squeezing due to meandering of the rolled material S does not occur, and specifically, the relationship between the meandering amount of the tail end of the rolled material S at the inlet side of the rolling stand F and the occurrence rate of squeezing is investigated in advance, and the maximum meandering amount of the tail end at which squeezing does not occur can be set as the limit meandering amount. Alternatively, because squeezing occurs when the rolled material S collides with the side guides, the limit meandering amount may be determined based on the distance between the side guides.

[0082] Finally, the leveling setting unit 42 sets the leveling of the rolling stand F based on the leveling set value calculated by the leveling set value calculation unit 41 while the rolling stand F is rolling the steady portion of the rolled material S (step S15). The change to the new leveling set value is performed during steady rolling of the rolled material S. This updates the leveling setting to one suitable for the tail end of the rolled material S to be able to bottom out before the tail end of the rolled material S starts to bottom out, thereby reducing meandering when the tail end of the rolled material S bottoms out. Furthermore, even if the leveling setting for the rolled material S is performed during steady rolling, continuous rolling of the rolled material S is being performed in the rolling stands upstream and downstream of the rolling stand F. For this reason, the constraint of the rolled material S by each rolling stand is less likely to promote meandering of the rolled material S during steady rolling.

[0083] The leveling setting unit 42 receives tracking information relating to biting and tailing of each rolling stand generated by the control controller 90, and after the threading process of the rolled material S is completed and the steady rolling process begins, sends a command for a new leveling set value for the rolling stand F to the control controller 90. As a result, the control controller 90 sends a command to the screw down devices 66a, 66b of the rolling stand F to achieve the set leveling.

[0084] [Modification] The entry wedge specifying unit 21 may estimate the entry wedge amount of the rolling stand downstream of the first rolling stand, using the entry wedge amount of the first rolling stand specified using the wedge meter 31 and the estimated leveling value of the rolling stand specified in the leveling estimation step. In this case, the entry wedge specifying unit 21 utilizes the exit wedge amount of the rolling stand F to calculate the entry wedge amount H of the rolling stand F+1 using the following formula (15): d2 Calculate.

[0085]

number

[0086] The tail end meandering amount prediction unit 24 may predict the meandering amount of the tail end of the rolled material S using a tail end meandering amount prediction model that predicts the meandering amount of the tail end of the rolled material S through learning using machine learning. As the tail end meandering amount prediction model, one learned by machine learning can be applied, which includes as input the wedge amount specified by the entry wedge specifying unit 21, the camber amount specified by the entry camber specifying unit 22, and the camber amount specified by the delivery camber specifying unit 23, and outputs the meandering amount of the tail end of the rolled material S at the entry side of the rolling stand.

[0087] Here, with reference to Fig. 11, the configuration of a tail end meandering amount prediction model generation unit according to one embodiment of the present invention will be described. As shown in Fig. 11, a tail end meandering amount prediction model generation unit 100 according to one embodiment of the present invention includes a database unit 101 and a machine learning unit 102. The database unit 101 accumulates actual data on the wedge amount specified by the entry wedge specifying unit 21, actual data on the camber amount specified by the entry camber specifying unit 22, actual data on the camber amount specified by the delivery camber specifying unit 23, and actual data on the meandering amount of the tail end of the material S to be rolled at the entry side of the rolling stand F. The actual data on the meandering amount of the tail end of the material S to be rolled at the entry side of the rolling stand F can be obtained by acquiring the amount of deviation of the material S from the center position in the width direction of the rolling mill when the camber amount is specified using the entry camber specifying unit 22.

[0088] The database unit 101 may store one or more pieces of actual data selected from the rolling operation parameters of the rolling stand F as needed. The rolling operation parameters of the rolling stand F are operation parameters that specify the rolling conditions at the front end of the rolled material S in the rolling stand F, and may include, for example, the rolling load, differential load, entry thickness, exit thickness, interstand tension during steady rolling, deformation resistance and temperature of the rolled material. This is because the rolling load and differential load of the rolled material S affect the elastic deformation of each roll of the rolling stand F, which in turn affects the roll gap distribution in the width direction of the work rolls 61a, 61b. This is also because other operation parameters indirectly affect the rolling load. Furthermore, the database unit 101 may store one or more pieces of actual data selected from operation parameters related to the temperature change in the longitudinal direction of the rolled material S as needed. The operation parameters related to the temperature change in the longitudinal direction of the rolled material S are parameters that affect the temperature change from the front end to the tail end of the rolled material S. Specifically, these factors include the length, weight, rolling speed, and acceleration rate of the material S to be rolled. These affect the rolling time in the rolling stand F from when the material S is threaded until it reaches the bottom, and affect the temperature change from the front to the rear end of the material S to be rolled. The temperature change from the front to the rear end of the material S to be rolled affects the thermal expansion of the work rolls not only in the rolling stand F but also in the stands upstream of it. This causes fluctuations in the wedge amount from the front to the rear end of the material S to be rolled, which affects the amount of meandering at the rear end of the material S to be rolled.

[0089] Furthermore, the database unit 101 may store one or more pieces of actual data selected from the rolling operation parameters of the roughing mill 5 as needed. The rolling operation parameters of the roughing mill 5 refer to parameters that specify the rolling conditions in the roughing mill 5 before the rolled material S is loaded into the finishing mill 6. Specifically, these parameters include the number of rolling passes by the roughing mill 5, the rolling load, differential load, and off-center amount in each rolling pass of the roughing mill 5, and the width reduction amount by the edger installed in the roughing mill 5. The number of rolling passes, rolling load, differential load, and off-center amount by the roughing mill 5 affect the temperature distribution and wedge amount in the longitudinal direction of the rough bar transported to the finishing mill 6. Furthermore, the width reduction amount by the edger affects the change in the wedge amount in the longitudinal direction of the rough bar transported to the finishing mill 6 if the rolled material S is off-center during horizontal rolling by the roughing mill 5. Therefore, this causes fluctuations in the amount of wedge from the leading edge to the tail end of the material S to be rolled, which affects the amount of meandering at the tail end of the material S to be rolled.

[0090] The performance data stored in the database unit 101 may be acquired as appropriate from the host computer 92, the control computer 91, or the control controller 90. Alternatively, a data acquisition unit 103 may be provided to collect this performance data, and the performance data may be temporarily stored in the data acquisition unit 103, and a data set in which multiple types of performance data are associated may be generated and then stored in the database unit 101. Since the data stored in the database unit 101 may be acquired at different times, by associating multiple types of performance data in the data acquisition unit 103, it is possible to configure data sets in which the data correspond to each other.

[0091] The tail-end meandering amount prediction model generating unit 100 may be provided in the meandering amount prediction device 20. The tail-end meandering amount prediction model generating unit 100 may be provided in the control computer 91, or may be provided in an independent computer capable of communicating with other devices. The tail-end meandering amount prediction model generating unit 100 may be configured as a device separate from the database unit 101 using a device capable of receiving the data sets stored in the database unit 101. The database unit 101 stores 100 or more data sets. Preferably, the database unit 101 stores 1,000 or more data sets, and more preferably, 10,000 or more data sets. The data stored in the database unit 101 may be screened as necessary.

[0092] The machine learning unit 102 uses the data set accumulated in the database unit 101 to generate a tail end meandering amount prediction model M that predicts the amount of meandering of the tail end of the rolled material S on the entry side of the rolling stand F by machine learning using a plurality of learning data, the input data including actual data on the wedge amount specified by the entry wedge specifying unit 21, actual data on the camber amount specified by the entry camber specifying unit 22, and actual data on the camber amount specified by the delivery camber specifying unit 23, and the output data being the amount of meandering of the tail end of the rolled material S on the entry side of the rolling stand F. The tail end meandering amount prediction model M may also be generated using actual data on rolling operation parameters at the front end of the rolled material S, actual data on operation parameters related to temperature changes in the longitudinal direction of the rolled material S, and actual data on rolling operation parameters of the roughing mill 5 as input data.

[0093] The machine learning model used to generate the tail meandering amount prediction model M can be any machine learning model as long as it provides sufficient prediction accuracy for the amount of meandering at the tail end for practical use. For example, commonly used neural networks (including deep learning and convolutional neural networks), decision tree learning, random forests, support vector regression, etc. may be used. An ensemble model combining multiple models may also be used. For example, the tail meandering amount prediction model M can be generated by machine learning using a general neural network such as the one shown in Figure 12. In particular, deep learning does not take into account the problem of multicollinearity, and other operational parameters that are correlated with the amount of meandering at the tail end of the rolled material S can also be freely selected as inputs, thereby improving the prediction accuracy for the amount of meandering at the tail end. For example, a neural network with two to three hidden layers, three to five nodes, and a sigmoid function as the activation function can be used.

[0094] The machine learning unit 102 may improve the estimation accuracy of the tail end meandering amount by dividing the data set accumulated in the database unit 101 into training data and test data and performing learning. For example, the machine learning unit 102 may use the training data to learn weight coefficients of a neural network, and generate the tail end meandering amount prediction model M by appropriately changing the structure of the neural network (the number of intermediate layers or the number of nodes) so as to increase the accuracy rate of the tail end meandering amount in the test data. The weight coefficients can be updated using an error propagation method. Note that the tail end meandering amount prediction model M may be updated to a new model by re-learning, for example, every six months or every year. This is because the more data stored in the database unit 101, the more accurate the tail end meandering amount can be predicted. Therefore, by updating the tail end meandering amount prediction model M based on the latest data, a tail end meandering amount prediction model that reflects changes in the manufacturing conditions of a hot-rolled steel sheet manufactured using a hot rolling line can be generated. [Example]

[0095] As an embodiment of the present invention, an example in which the present invention is applied to a finishing rolling mill consisting of seven rolling stands arranged in a hot rolling line will be described. The purpose of this embodiment was to reduce the amount of meandering at the tail end of the rolled material S in the second rolling stand of the finishing rolling mill. Specifically, an entry wedge specifying unit 21 that specifies the wedge amount at the front end of the rolled material S at the entry side of the second rolling stand (rolling stand F2), an entry camber specifying unit 22 that specifies the camber amount at the front end of the rolled material S at the entry side of rolling stand F2, and an exit camber specifying unit 23 that specifies the camber amount at the front end of the rolled material S at the exit side of rolling stand F2 were arranged, and a meandering amount prediction device 20 having a tail end meandering amount predictor 24 was configured as shown in FIG. 4 . The entry wedge specifying unit 21 was equipped with thickness gauges arranged on the work side and drive side of the rolled material S, and the wedge amount at the front end of the rolled material S was determined from the thickness data obtained from the thickness gauges. In addition, the entry camber identification unit 22 and the exit camber identification unit 23 use an area camera to capture the planar shape of the tip of the rolled material S, and identify the widthwise end of the rolled material S by performing image processing on the captured image, thereby identifying the widthwise center position of the rolled material S.

[0096] In this example, a low-carbon steel plate with a width of 1250 mm was used as the material S to be rolled. The entry thickness of the material S in the rolling stand F2 of the finishing rolling mill was 20 mm, and the exit thickness was 13 mm. In this example, a zero point adjustment was performed in advance to ensure that the command leveling of the rolling stand F2 was set appropriately, and the material S was then rolled. The wedge amount and camber amount at the leading end of the material S were determined as the leading end of the material S passed through rolling stand F1 and reached rolling stand F2. The camber amount at the leading end of the material S was also determined as the leading end of the material S passed through rolling stand F2 and reached rolling stand F3. As a result, the wedge amount at the leading end of the material S at the entry side of rolling stand F2 was 0.05 mm. In addition, the camber amount at the tip of the rolled material S at the entry side of the rolling stand F2 was 0 mm, and the camber amount at the tip of the rolled material S at the exit side of the rolling stand F2 was -20 mm.

[0097] Then, the tail end meandering amount prediction unit 24 predicted the meandering amount of the tail end of the rolled material S in the rolling stand F2. In predicting the meandering amount of the tail end of the rolled material S, a leveling estimation step was performed to obtain an estimated leveling value S at the front end of the rolled material S using Equation (5). d As a result, the estimated leveling value S d Then, in the meandering amount estimation step, the meandering amount y of the tail end of the rolled material S was calculated using Equation (11). c As a result, the meandering amount y c was predicted to be -28 mm. On the other hand, by using the inlet camber specifying unit 22, it was possible to specify the widthwise center position of the tail end portion of the rolled material S as well, and the specified meandering amount of the tail end portion of the rolled material S was -25 mm. This confirmed that the meandering amount of the tail end portion of the rolled material S can be predicted with high accuracy by the meandering amount prediction device 20 of this embodiment.

[0098] Next, an example of a meandering amount control for reducing the meandering amount of the tail end of the rolled material S of the same size will be described. In this example, a meandering amount control device 40 is provided, and the meandering amount y of the tail end of the rolled material S predicted by the meandering amount prediction device 20 installed in the rolling stand F2 is used. c and sends the leveling set value to the control controller 90 as a command value for the screw down device of the rolling stand F2. In this case, the leveling set value calculation unit 41 calculates a leveling set value for reducing meandering of the tail end of the material S to be rolled, and the leveling setting unit 42 sends a control command to the control controller 90 to set the leveling set value while the steady portion of the material S is being rolled in the rolling stand F2.

[0099] Table 1 shows an example of controlling the amount of meandering at the tail end of the rolled material S according to this embodiment. In the example shown in Table 1, the wedge amount at the front end of the rolled material S at the entry side of rolling stand F2 was 0.05 mm, the entry-side camber amount at the front end of the rolled material S was 0 mm, and the exit-side camber amount was -21 mm. In this case, the meandering amount prediction device 20 predicted the amount of meandering at the tail end of the rolled material S to be -30 mm. However, the leveling set value calculation unit 41 had previously set the limit for the amount of meandering to 10 mm in absolute value, and since the predicted amount of meandering exceeded the limit, the leveling set value was determined to be 0.06 mm. Then, the leveling set value calculated while the steady portion of the rolled material S was being rolled in rolling stand F2 was set, and the tail end of the rolled material S was allowed to come out of the roll. The amount of meandering at the tail end of the rolled material S was a satisfactory -5 mm.

[0100] On the other hand, Table 1 shows, as a comparative example, an example in which control of the meandering amount of the tail end of the rolled material S is not performed. In the comparative example, the wedge amount of the front end of the rolled material S at the entry side of rolling stand F2 was 0.03 mm, the entry-side camber amount of the front end of the rolled material S was -1 mm, and the exit-side camber amount was -19 mm. In the comparative example, since control of the meandering amount of the tail end of the rolled material S was not performed, the leveling setting value was 0 mm, and rolling was performed with the command leveling set in advance. As a result, the meandering amount of the tail end of the rolled material S was -24 mm, which was larger than in the example. From the above, it was confirmed that the example can effectively reduce the meandering amount of the tail end of the rolled material S.

[0101] [Table 1]

[0102] Although the present invention has been described above as an embodiment, the present invention is not limited to the descriptions and drawings that form part of the disclosure of the present invention. In other words, other embodiments, examples, and operational techniques that can be made by those skilled in the art based on the present invention are all included in the scope of the present invention. [Explanation of symbols]

[0103] 1 Hot rolling line 2 Furnace 3 Descaling device 4 Width reduction press device 5 Roughing mill 6 Finishing rolling mill 7 Cooling device 8 Coiler (winding machine) 10 Inlet transport roll 11 Exit transport roll 12 Inter-stand looper 20. Meandering amount prediction device 21 Inlet wedge identification part 22 Entry camber specification part 23 Exit camber specification part 31 wedge meter 32 Incoming camera 33 Exit camera 40 Snake amount control device 41 Leveling setting value calculation unit 42 Leveling setting section 61a, 61b Work rolls 62a, 62b Backup roll 63, 63a, 63b Bearing box (backup roll chock) 64, 64a, 64b Housing 65, 65a, 65b Load Cell 66,66a,66b Reduction device 90 Control Controller 91 Control computer 92 Upper computer F, F1 to F7 rolling stands PL Pass Line S Rolled material

Claims

1. A meandering amount prediction device for a rolled material that predicts the meandering amount of a tail end portion of a rolled material in a rolling stand that constitutes a hot finishing rolling mill, comprising: an inlet wedge specifying unit that specifies a wedge amount of the tip end of the rolled material at the inlet side of the rolling stand; an entry camber specifying unit that specifies the amount of camber at the tip end of the rolled material at the entry side of the rolling stand; an outlet camber specifying unit that specifies the amount of camber at the tip end of the rolled material at the outlet side of the rolling stand; a tail end meandering amount prediction unit that predicts the amount of meandering of the tail end of the material to be rolled in the rolling stand, using the wedge amount of the front end of the material to be rolled specified by the entry-side wedge specifying unit, the camber amount of the front end of the material to be rolled specified by the entry-side camber specifying unit, and the camber amount of the front end of the material to be rolled specified by the delivery-side camber specifying unit; A device for predicting the meandering amount of a rolled material, comprising:

2. a leveling set value calculation unit that calculates a leveling set value of the rolling stand based on the meandering amount of the tail end portion of the rolled material predicted by the rolled material meandering amount prediction device according to claim 1; a leveling setting unit that sets the leveling of the rolling stand based on the leveling set value calculated by the leveling set value calculation unit during rolling of the steady portion of the rolled material; A meandering amount control device for a rolled material comprising:

3. A method for predicting the meandering amount of a rolled material, the method comprising: an inlet wedge specifying step of specifying a wedge amount of the tip end portion of the rolled material at the inlet side of the rolling stand; an entry camber specifying step of specifying a camber amount of a leading end portion of the rolled material at the entry side of the rolling stand; an outlet camber specifying step of specifying a camber amount of a leading end portion of the rolled material at the outlet side of the rolling stand; a tail end meandering amount prediction step of predicting a meandering amount of the tail end of the material to be rolled in the rolling stand using the wedge amount of the front end of the material to be rolled specified in the entry-side wedge specifying step, the camber amount of the front end of the material to be rolled specified in the entry-side camber specifying step, and the camber amount of the front end of the material to be rolled specified in the delivery-side camber specifying step; A method for predicting the amount of meandering of a rolled material, comprising:

4. 4. The method for predicting the amount of meandering of a rolled material according to claim 3, wherein the tail end meandering amount prediction step includes a step of predicting the amount of meandering of the tail end of the rolled material in the rolling stand using a tail end meandering amount prediction model learned by machine learning, the tail end meandering amount prediction model including as inputs the wedge amount of the tip end of the rolled material specified in the entry wedge specifying step, the camber amount of the tip end of the rolled material specified in the entry camber specifying step, and the camber amount of the tip end of the rolled material specified in the delivery camber specifying step, and outputting the amount of meandering of the tail end of the rolled material in the rolling stand.

5. a leveling set value calculation step of calculating a leveling set value of the rolling stand based on the meandering amount of the tail end portion of the rolled material predicted by the method for predicting the meandering amount of the rolled material according to claim 3 or 4; a leveling setting step of setting the leveling of the rolling stand based on the leveling set value calculated in the leveling set value calculation step while rolling the steady portion of the rolled material; A method for controlling the amount of meandering of a rolled material, comprising:

6. A method for manufacturing a metal strip, comprising the step of manufacturing a metal strip using the method for controlling the meandering amount of a rolled material according to claim 5.

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