Sheet width control device for a reversible rolling mill

Abstract

This sheet width control device is applicable to a reversing rolling mill that comprises: an edger that has a pair of edger rolls that perform edge rolling on a material being rolled; and a horizontal rolling mill that is disposed downstream of the edger and has a pair of horizontal rolls that perform horizontal rolling on the material being rolled. The sheet width control device comprises a reduction control device, a reduction position detector, a tracking device, and a sheet width actual value calculation device. The reduction control device is configured to cause the edger to operate such that the pair of edger rolls make contact with the material being rolled during reverse pass rolling. The reduction position detector is configured to detect the reduction position of the edger when the pair of edger rolls are in contact with the material being rolled during reverse pass rolling. The tracking device is configured to track the position in the longitudinal direction of the material being rolled during reverse pass rolling. The sheet width actual value calculation device is configured to calculate a sheet width actual value for the material being rolled at a plurality of positions in the longitudinal direction on the basis of the output of the reduction position detector and the output of the tracking device.

Description

Technical Field

[0001] The present disclosure relates to a plate width control device for a reversible rolling mill.

Background Art

[0002] In a hot rolling line, a material to be rolled is processed into a product size through a rough rolling process and a finish rolling process. The rough rolling process is performed by a reversible rolling mill including a horizontal rolling mill and an edger. The edger is installed upstream of the horizontal rolling mill. The edger has a pair of edger rolls for performing width rolling on the material to be rolled. The horizontal rolling mill has a pair of horizontal rolls for performing horizontal rolling on the material to be rolled. In the rough rolling process, a forward pass in which the material to be rolled flows in the forward direction and a reverse pass in which the material to be rolled flows in the reverse direction are alternately repeated. In the rough rolling process, while repeating the forward pass and the reverse pass, width rolling by the edger rolls and horizontal rolling by the horizontal rolls are repeated, and the material to be rolled is processed into a plate width suitable for the start of finish rolling. As prior arts related to reversible rolling mills, for example, Patent Document 1 and Patent Document 2 are disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the finish rolling process has a small plate width change ability, it is required to create a plate width in the rough rolling process. For this purpose, it is necessary to obtain the plate width of the material to be rolled during rough rolling over the entire length. In particular, in order to finish the plate width in the last forward pass rolling, it is necessary to obtain the plate width from the reverse pass rolling to before the last forward pass rolling.

[0005] However, width gauges capable of measuring the sheet width of the material to be rolled are often installed at positions far from the inlet side of the reversing mill in the hot rolling line. In order to measure the sheet width of the material to be rolled over its entire length using such a width gauge, the material to be rolled must be transported to the installation position of the width gauge after it has passed through the edger, resulting in a time loss. Depending on the position of the width gauge on the inlet side, the material to be rolled may reach the width gauge during reverse pass rolling. However, for productivity improvement, after the material to be rolled has passed through the edger, a reverse operation is promptly performed and rolling in the forward pass is started. For this reason, the sheet width can be measured only for a part of the rear end side of the material to be rolled, and the sheet width cannot be measured over the entire length.

[0006] One object of the present disclosure is to provide a sheet width control device for a reversing mill that can obtain the sheet width of the material to be rolled over its entire length while avoiding a decrease in productivity due to time loss.

Means for Solving the Problem

[0007] The sheet width control device of the present disclosure is applied to a reversing mill including an edger having a pair of edger rolls for performing width rolling on the material to be rolled, and a horizontal rolling mill disposed downstream of the edger and having a pair of horizontal rolls for performing horizontal rolling on the material to be rolled. The sheet width control device of the present disclosure includes a roll gap control device, a roll gap position detector, a tracking device, and a sheet width actual value calculator. The roll gap control device is configured to operate the edger so that a pair of edger rolls contact the material to be rolled during reverse pass rolling. The roll gap position detector is configured to detect the roll gap position of the edger when a pair of edger rolls are in contact with the material to be rolled during reverse pass rolling. The tracking device is configured to track the longitudinal position of the material to be rolled during reverse pass rolling. And the sheet width actual value calculator is configured to calculate the sheet width actual values at a plurality of positions in the longitudinal direction of the material to be rolled based on the output of the roll gap position detector and the output of the tracking device.

[0008] In the plate width control device of the present disclosure, the rolling reduction control device may be configured to apply constant load control to the edgers so that a state in which a pair of edger rolls are in contact with the material to be rolled is maintained during reverse-pass rolling. Alternatively, the rolling reduction control device may be configured to repeatedly execute the following processes during reverse-pass rolling. The first process is to operate the edgers so as to reduce the distance between the pair of edger rolls from a state where the pair of edger rolls are not in contact with the material to be rolled. The second process is to detect contact of the pair of edger rolls with the material to be rolled from the measured load of the edgers. And the third process is to operate the edgers so as to increase the distance between the pair of edger rolls when contact of the pair of edger rolls with the material to be rolled is detected.

[0009] The plate width control device of the present disclosure may further include a plate width meter arranged downstream of the edgers and configured to measure the plate width of the material to be rolled. In this case, the plate width actual value calculation device may be configured to correct the plate width actual value using the plate width predicted from the measured value of the plate width meter and the width increase amount due to horizontal rolling. Alternatively, the plate width control device of the present disclosure may further include a plate width meter arranged upstream of the edgers and configured to measure the plate width of the material to be rolled. In this case, the plate width actual value calculation device may be configured to correct the plate width actual value using the measured value of the plate width meter.

[0010] The plate width control device of the present disclosure may further include a rolling reduction position correction calculation device. The rolling reduction position correction calculation device may be configured to calculate a correction amount for the rolling reduction position of the edgers in the next forward-pass rolling based on the plate width actual value. More specifically, the correction amount for the rolling reduction position may be calculated for each position in the longitudinal direction in accordance with the distribution of the plate width actual value in the longitudinal direction, or the correction amount for the rolling reduction position as a whole in the longitudinal direction may be calculated based on the average value of the plate width actual value in the longitudinal direction.

Advantages of the Invention

[0011] According to the sheet width control device of the present disclosure, based on the rolling-down position of the edger roll when the edger roll is in contact with the material to be rolled during reverse-pass rolling and the position in the longitudinal direction of the material to be rolled that is tracked during reverse-pass rolling, the actual sheet width values at a plurality of positions in the longitudinal direction of the material to be rolled are calculated. According to this, since it is not necessary to convey the material to be rolled more than the distance required for reverse-pass rolling, it is possible to obtain the sheet width of the material to be rolled over the entire length while avoiding a decrease in productivity due to time loss.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0013] 1. First Embodiment 1-1. Configuration of Reversible Rolling Mill Hereinafter, with reference to FIG. 1, the configuration of the reversible rolling mill 10 according to the first embodiment of the present disclosure will be described.

[0014] The reversible rolling mill 10 is equipped with a roller table 80 for conveying the material to be rolled (slab) 90. The roller table 80 has a plurality of rollers capable of driving in the forward direction and the reverse direction. A speed detector 81 for detecting its conveying speed is attached to the roller table 80. The reversible rolling mill 10 is equipped with an edger 20 for width rolling and a horizontal rolling mill 30 for horizontal rolling on the conveying line of the material to be rolled 90 by the roller table 80. The horizontal rolling mill 30 is arranged downstream of the conveying line with respect to the edger 20.

[0015] The edger 20 is equipped with a pair of edger rolls 25 arranged to sandwich the material to be rolled 90 from the left and right. The edger rolls 25 are supported by roll chocks 26, that is, axle boxes equipped with bearings. The edger 20 is equipped with a rolling reduction device 22 for moving the edger rolls 25 supported by the roll chocks 26 in the width direction of the material to be rolled 90. The rolling reduction device 22 is equipped with a hydraulic cylinder and can perform a high-speed rolling reduction operation by the hydraulic cylinder.

[0016] The edger 20 is equipped with a load measuring device 24 for detecting the rolling load by the rolling reduction device 22. Specifically, the load measuring device 24 is a load cell provided on the roll chock 26. However, a hydraulic detector provided on the hydraulic cylinder of the rolling reduction device 22 can also be used as the load measuring device 24. Further, the edger 20 is equipped with a rolling reduction position detector 23 for detecting the rolling reduction position by the rolling reduction device 22. The rolling reduction position detector 23 outputs the oil column length of the hydraulic cylinder as the detected value of the rolling reduction position. Here, the rolling reduction position is a value indicating the gap between the pair of edger rolls 25 at no load (during non-rolling). The rolling reduction position detector 23 calculates and outputs the rolling reduction position based on the actually measured values of the oil column lengths of the hydraulic cylinders on both sides. For example, the gap of the actual edger rolls 25 is measured at a certain reference oil column length (this process is called zero adjustment), and a value obtained by subtracting the change amount of the oil column length from the zero adjustment time from the measured value (roll gap at zero adjustment time) is output as the detected value of the rolling reduction position.

[0017] The horizontal rolling mill 30 includes a pair of horizontal rolls 31 arranged to sandwich the material to be rolled 90 from above and below. A speed detector 32 for detecting the rotational speed of the horizontal roll 31 is attached to the horizontal roll 31. Further, a hot piece detector (HMD) 100 is arranged on the outlet side of the horizontal rolling mill 30. However, the hot piece detector 100 arranged in the reversing rolling mill 10 is not just one, but a plurality of hot piece detectors 100 are arranged at multiple locations on the conveyance line of the material to be rolled 90.

[0018] 1-2. Configuration of the sheet width control device Next, with continued reference to FIG. 1, the configuration of the sheet width control device 200 applied to the reversing rolling mill 10 configured as described above will be described.

[0019] The sheet width control device 200 is composed of a roll gap control device 21, a sheet width actual value calculation device 40, a setting calculation device 50, a roll gap position correction calculation device 60, and a tracking device 70. These devices 21, 40, 50, 60, 70 constituting the sheet width control device 200 may be application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), central processing units (CPUs), or other processing devices. One or more of the devices 21, 40, 50, 60, 70 may be a combination of two or more ASICs, FPGAs, CPUs, or other processing devices. The ASICs, FPGAs, CPUs, and other processing devices constituting the sheet width control device 200 include a series of executable instructions. When those instructions are executed, the corresponding ASICs, FPGAs, CPUs, and other processing devices are triggered to execute the functions of the respective devices 21, 40, 50, 60, 70 described later.

[0020] The setting calculation device 50 is configured to give various setting calculation values 51 to the roll gap control device 21. The setting calculation value 51 includes a sheet width target value 51a for the material to be rolled 90. The load target value 51a is a value predetermined within the range from the minimum load to the maximum load. The minimum load is the lower limit value at which the load can be measured stably, and the maximum load is the mechanical allowable upper limit value of the edger 20.

[0021] The rolling reduction control device 21 operates according to various set calculation values 51 provided by the set calculation device 50. Further, the rolling reduction load detected by the load measuring device 24 and the rolling reduction position detected by the rolling reduction position detector 23 are input to the rolling reduction control device 21. The rolling reduction control device 21 is configured to transmit the detected value of the rolling reduction position input from the rolling reduction position detector 23 during reverse pass rolling to the sheet width actual value calculation device 40 as the rolling reduction position actual value 21a.

[0022] The tracking device 70 acquires the rotational speed of the horizontal roll 31 detected by the speed detector 32, the conveyance speed of the roller table 80 detected by the speed detector 81, and the output of the hot sheet detector 100. The tracking device 70 is configured to generate tracking information 71 indicating the position of the material to be rolled 90 in the longitudinal direction using the information acquired during reverse pass rolling. The generated tracking information 71 is transmitted to the sheet width actual value calculation device 40.

[0023] The sheet width actual value calculation device 40 includes a storage device 41 and a full-length sheet width actual value calculation unit 42. The rolling reduction position actual value 21a transmitted from the rolling reduction control device 21 is stored in the storage device 41. Further, the tracking information 71 generated by the tracking device 70 is also stored in the storage device 41. Both the rolling reduction position actual value 21a and the tracking information 71 are information acquired during reverse pass rolling of the material to be rolled 90, and are linked to each other according to the acquired timing. The acquisition timing of this information is determined in advance by a fixed or variable sampling time interval or the position of the material to be rolled 90 in the longitudinal direction.

[0024] The full-length sheet width actual value calculation unit 42 is configured to calculate the actual values of the sheet width of the material to be rolled 90 at a plurality of positions in the longitudinal direction based on the information stored in the storage device 41. Details of the calculation method of the actual value of the sheet width will be described later. The actual value of the sheet width calculated by the full-length sheet width actual value calculation unit 42 is input to the rolling reduction position correction calculation device.

[0025] The reduction position correction calculation device 60 is configured to calculate the correction amount of the reduction position by the reduction device 22 based on the actual value of the plate width calculated by the full-length plate width actual value calculation unit 42. The correction amount of the reduction position calculated by the reduction position correction calculation device 60 is used for the control of the edger 20 by the reduction control device 21 in the next forward pass rolling after the reverse pass rolling in which the actual value of the plate width is calculated. Details of the calculation method of the correction amount of the reduction position will be described later.

[0026] 1-3. Processing of the Plate Width Control Device during Reverse Pass Rolling In reverse pass rolling, the material to be rolled 90 is conveyed in the direction of the arrow by the roller table 80, and during this time, the material to be rolled 90 is sandwiched from both left and right by a pair of edger rolls 25. During reverse pass rolling, constant load control is applied to the edger 20 by the reduction control device 21. In constant load control, the reduction device 22 is operated so that the rolling load detected by the load measuring instrument 24 matches the load target value 51a.

[0027] FIG. 2 is a diagram showing the operation of the edger roll 25 during reverse pass rolling. By performing constant load control, the gap 28 between the edger rolls 25 is controlled so that the state in which the left and right edger rolls 25 are in contact with the material to be rolled 90 is maintained over the entire length of the material to be rolled 90. Then, while the edger roll 25 is relatively moving along the side surface of the material to be rolled 90, the actual reduction position value 21a corresponding to the width direction position of the edger roll 25 is acquired by the reduction position detector 23.

[0028] After the completion of reverse pass rolling, the plate width actual value of the material to be rolled 90 is calculated by the plate width actual value calculation device 40. The calculation of the plate width actual value is performed by the full-length plate width actual value calculation unit 42. The full-length plate width actual value calculation unit 42 calculates the full-length plate width actual value by the following formula using the actual reduction position value 21a stored in the storage device 41.

Equation

Equation

Number

Number

Number

Number

[0029] The edge mill elongation is calculated from the rolling load using a mill curve represented by a quadratic equation or the like. The wear amount and thermal expansion amount of the edge roll are considered as the change amount from the edge roll diameter at zero adjustment. The wear amount is periodically calculated and integrated every few seconds from the predicted or measured rolling load, rolling length, etc. The thermal expansion amount is periodically calculated and integrated every few seconds from the predicted or measured roll temperature. The thermal expansion amount is periodically calculated and integrated every few seconds from the predicted or measured roll temperature. When the edge roll is worn, the wear amount becomes a positive value, and when it is thermally expanded, the thermal expansion amount becomes a positive value.

[0030] In this embodiment, during reverse pass rolling, the state where the edge roll 25 and the material to be rolled 90 are in contact is maintained by constant load control. Therefore, the actual rolling reduction value 21a can be obtained at any position in the longitudinal direction. In order to obtain the actual plate width value of the entire length with high precision, the larger the number of measurement points for obtaining the actual rolling reduction value 21a and the tracking information 71, the better.

[0031] Also, in this embodiment, the load target value 51a of the constant load control is set to a sufficiently small value within the range where the load can be measured stably. By doing so, the width reduction amount in reverse pass rolling can be kept small, and the generation of the dog bone of the material to be rolled 90 and the width fluctuation (plastic deformation) due to the width return can be made small enough to be ignored. As a result, the actual plate width value of the entire length, particularly the actual plate width value at the head and tail ends, can be obtained with high precision.

[0032] As described above, in this embodiment, based on the rolling reduction position of the edger 20 obtained by the constant load control during reverse-pass rolling and the position in the longitudinal direction of the material to be rolled 90 tracked during reverse-pass rolling, the actual plate width value of the entire length of the material to be rolled 90 is calculated. According to this, it is not necessary to convey the material to be rolled 90 over a distance longer than the distance required for reverse-pass rolling. Therefore, according to the plate width control device 200 according to this embodiment, it is possible to obtain the plate width of the material to be rolled 90 over the entire length while avoiding a decrease in productivity due to time loss.

[0033] 1-4. Processing of the Plate Width Control Device during Forward-Pass Rolling After reverse-pass rolling, forward-pass rolling is executed. FIG. 3 shows the processing during forward-pass rolling by the plate width control device 200. In forward-pass rolling, the material to be rolled 90 is conveyed in the direction of the arrow by the roller table 80, and during that time, the material to be rolled 90 is rolled from both the left and right by the edger 20. The rolling of the material to be rolled 90 by the edger 20 is performed so that the plate width at the end of forward-pass rolling becomes constant over the entire length.

[0034] Before the start of forward-pass rolling, the correction amount of the rolling reduction position of the edger 20 is calculated by the rolling reduction position correction calculation device 60. The correction amount of the rolling reduction position is calculated using the actual plate width value of the entire length calculated during reverse-pass rolling. The correction amount of the rolling reduction position may be calculated for each position in the longitudinal direction in accordance with the distribution of the actual plate width value in the longitudinal direction, or the correction amount of the rolling reduction position as a whole in the longitudinal direction may be calculated based on the average value of the actual plate width values in the longitudinal direction. The following formula is an example of a formula for calculating the correction amount of the rolling reduction position.

Equation

Equation

Equation

Equation

[0035] The edger reduction efficiency is expressed as a function of the thickness / width ratio of the plate and usually takes a value of about 0.2 to 0.8. As the reference value of the plate width for the reverse pass (the (i - 1)th pass), the average value of a predetermined range of the actual plate width values is used. However, the calculated plate width setting value may be used instead of the average value.

[0036] The reduction position correction calculator 60 inputs the edger reduction position correction amount 61 calculated by the above formula to the reduction controller 21. The edger reduction position correction amount 61 is calculated for each position in the longitudinal direction in accordance with the distribution of the actual plate width values in the longitudinal direction. Further, the setting calculator 50 inputs the load target value 51a to the reduction controller 21. The reduction controller 21 synchronizes the timing among the input information and the tracking information 71 input from the tracking device 70, and controls the gap between the edger rolls 25. Thereby, the width accuracy of the material to be rolled 90 sent to the downstream finish rolling process is improved, and the yield of the product is improved.

[0037] 1 - 5. Configuration of the First Modification Example of the Plate Width Controller and Correction Process of the Actual Plate Width Value FIG. 4 shows a first modification of the sheet width control device 200. In the first modification, the sheet width control device 200 includes a sheet width meter 110 downstream of the reversible rolling mill 10. Further, the sheet width actual value calculation device 40 of the sheet width control device 200 is composed of a storage device 41, a full-length sheet width actual value calculation unit 42, and a sheet width actual value correction unit 43.

[0038] In the first modification, during the forward pass rolling before the reverse pass rolling, the rolled material 90 that has passed through the horizontal rolling mill 30 reaches the sheet width meter 110, and its sheet width is measured. However, after it is confirmed that the rear end (the rear end in the advancing direction of the rolling line) of the rolled material 90 has passed through the horizontal rolling mill 30, the conveying direction of the roller table 80 is promptly switched from the forward pass to the reverse pass. Therefore, instead of measuring the sheet width over the entire length of the rolled material 90, only the sheet width of a part 91 on the front end side that has reached the sheet width meter 110 before the rear end of the rolled material 90 passes through the horizontal rolling mill 30 is measured. The sheet width measurement value 111 obtained by the sheet width meter 110 is transmitted to the sheet width actual value calculation device 40 and stored in the storage device 41.

[0039] In the first modification, the full-length sheet width actual value obtained by the full-length sheet width actual value calculation unit 42 is corrected by the sheet width actual value correction unit 43. The correction amount of the sheet width actual value is calculated by the following formula using the sheet width measurement value obtained by the sheet width meter 110 during the forward pass rolling.

Equation

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[0040] Generally, the plate width gauge 110 downstream of the reversible rolling mill 10 is often installed at a position more than about 5 m away from the reversible rolling mill 10 in order to avoid measurement disturbances caused by roll cooling water or the like. When reverse pass rolling is performed after forward pass rolling, it is quickly switched to reverse pass rolling after the end of forward pass rolling. For this reason, a section where measurement cannot be performed (corresponding to the distance from the horizontal rolling mill 30 to the plate width gauge 110) occurs in the plate width gauge 110 downstream of the reversible rolling mill 10. The plate width actual value correction amount can be calculated in an arbitrary section within the section where the plate width measurement value could be measured.

[0041] 1-6. Configuration of the Second Modification Example of the Sheet Width Control Device and Correction Process of the Sheet Width Actual Value FIG. 5 shows a second modification example of the sheet width control device 200. In the second modification example, the sheet width control device 200 includes a sheet width meter 110 upstream of the reversing rolling mill 10. Further, the sheet width actual value calculation device 40 of the sheet width control device 200 is composed of a storage device 41, a full-length sheet width actual value calculation unit 42, and a sheet width actual value correction unit 43.

[0042] In the second modification example, during reverse-pass rolling, the rolled material 90 that has passed through the edger 20 reaches the sheet width meter 110, and its sheet width is measured. However, after it is confirmed that the leading end of the rolled material 90 (the leading end in the advancing direction of the rolling line) has passed through the horizontal rolling mill 30, the conveyance direction of the roller table 80 is promptly switched from the reverse pass to the forward pass. Therefore, the sheet width is not measured over the entire length of the rolled material 90, but only the sheet width of a part 92 on the trailing end side that has reached the sheet width meter 110 before the leading end of the rolled material 90 passes through the edger 20 is measured. The sheet width measurement value 111 obtained by the sheet width meter 110 is transmitted to the sheet width actual value calculation device 40 and stored in the storage device 41.

[0043] In the second modification example, the sheet width actual value correction unit 43 corrects the full-length sheet width actual value obtained by the full-length sheet width actual value calculation unit 42. The correction amount of the sheet width actual value is calculated by the following formula using the sheet width measurement value obtained by the sheet width meter 110 during reverse-pass rolling.

Equation

Equation

Equation

[0044] Generally, the plate width meter 110 upstream of the reversible rolling mill 10 is installed near the outlet side of the upstream rolling mill. Since it is quickly switched to the forward pass rolling after the reverse pass rolling, there is a section that cannot be measured by the plate width meter 110 upstream of the reversible rolling mill 10 (corresponding to the distance from the plate width meter 110 to the edger 20). The plate width actual value correction amount can be calculated in any section within the section where the plate width measurement value can be measured.

[0045] In rolling facilities, in order to improve dimensional accuracy by calibrating mechanical wear and roll diameter changes that change over time, zero adjustment is performed every time the rolls are changed or the equipment is stopped. Since the horizontal rolling mill 30 can be measured by a method of bringing the rolls into contact with each other (kiss roll), zero adjustment can be performed under conditions (load) close to actual rolling. On the other hand, since the pair of edger rolls 25 are at a separated distance, zero adjustment by bringing the rolls into contact with each other cannot be performed. Therefore, conventionally, a method of indirectly measuring the edger roll gap, for example, a method of measuring the edger roll gap in a stopped state or a method of measuring by sandwiching a test material of a known dimension has been implemented. However, in the indirect method, measurement errors may occur, and zero adjustment of the edger roll gap may not be performed correctly.

[0046] Regarding this point, according to the above-described plate width control device, errors in the edger roll gap due to inaccurate zero adjustment or prediction errors of roll wear can be corrected, a highly accurate plate width actual value can be obtained, and the width rolling accuracy can be improved.

[0047] 2. Second Embodiment Next, a plate width control device according to the second embodiment of the present disclosure will be described. The plate width control device according to this embodiment has a basic configuration in common with the plate width control device according to the first embodiment. That is, the plate width control device according to this embodiment has the configuration shown in FIG. 1 in the same manner as the first embodiment. The difference between the plate width control device according to this embodiment and the plate width control device according to the first embodiment lies in the control of the edger 20 by the roll gap control device 21 performed during reverse pass rolling. Specifically, there is a difference in the operation of the edger roll 25 controlled by the roll gap control device 21.

[0048] FIG. 6 is a diagram showing the operation of the edger roll 25 during reverse-pass rolling according to the present embodiment. In FIG. 6, the moving line indicated by the broken line is the moving line showing the operation of the edger roll 25 relative to the material to be rolled 90, that is, the operation of the rolling-down position of the edger 20. In the second embodiment, a plurality of measurement points are predetermined in the longitudinal direction of the material to be rolled 90, and the actual plate width values are acquired for each measurement point. In the example shown in FIG. 6, the point where the moving line contacts the material to be rolled 90 is the measurement point at which the actual plate width value is acquired. The measurement points are determined by a constant or variable sampling time interval or length interval.

[0049] Before the start of reverse-pass rolling, the rolling-down position of the edger 20 is set to a position where the edger roll 25 does not contact the material to be rolled 90. Then, it is detected from the tracking information 71 that a predetermined measurement point of the material to be rolled 90 has reached the position of the edger roll 25 (time point t0).

[0050] Next, the edger 20 is operated in a direction to narrow the gap 28 between the edger rolls 25 (operation 1). The rolling-down speed of the edger 20 at this time is predetermined before the start of reverse-pass rolling in consideration of the response characteristics of the rolling-down device 22 and the load measuring device 24 and the control cycle of the rolling-down control device 21. Specifically, it is a constant speed or a speed determined by the rolling-down position.

[0051] During the control of the rolling-down speed, the rolling load and the change amount of the rolling load per unit time are monitored. Then, when the edger roll 25 contacts the material to be rolled 90 and the rolling load reaches the load target value (time point t1), the rolling-down position of the edger 20 and the longitudinal position of the material to be rolled 90 at that time are stored in the storage device 41. The load target value is a value predetermined within a range where the load can be measured stably and the width rolling-down amount or the dog-bone bulge amount does not exceed the allowable upper limit.

[0052] Thereafter, the edger 20 is operated to widen the gap 28 between the edger rolls 25 by a predetermined distance (operation 2). Then, the edger rolls 25 are made to wait while maintaining the gap 28 until the next measurement point of the material to be rolled 90 reaches the position of the edger rolls 25 (operation 3).

[0053] In the first embodiment, when constant load control is performed, the hydraulic cylinder of the rolling reduction device 22 is opened and closed, and each time, the direction of the sliding friction of the hydraulic cylinder changes. When a hydraulic pressure detector is used as the load measuring device 24, the change in the direction of the sliding friction becomes a disturbance in the constant load control and deteriorates the controllability of the constant load control. For this reason, in the first embodiment, there is a possibility that the contact state between the material to be rolled 90 and the edger rolls 25 cannot be kept equal over the entire length of the material to be rolled 90.

[0054] On the other hand, in the second embodiment, the direction of the operation of the hydraulic cylinder at the time of measuring the rolling reduction position always becomes the direction of closing the gap 28 between the edger rolls 25. For this reason, no change occurs in the direction of the sliding friction of the hydraulic cylinder, and the measurement conditions at the time of measuring the rolling reduction position are made uniform. Therefore, according to the second embodiment, the measurement accuracy of the plate width of the material to be rolled 90 can be further improved.

[0055] Note that the method for correcting the plate width actual value using the plate width measurement value described in the first and second modification examples of the first embodiment can also be applied to the plate width control device according to the second embodiment.

Explanation of Reference Numerals

[0056] 10 Reversing rolling mill 20 Edger 22 Rolling reduction device 21 Rolling reduction control device 23 Rolling reduction position detector 24 Load measuring device 25 Edger roll 30 Horizontal rolling mill 40 Plate width actual value calculation device 50 Setting calculation device 60 Reduction position correction calculation device 70 Tracking device 31 Horizontal roll 90 Material to be rolled 110 Plate width gauge 200 Plate width control device

Claims

1. In a plate width control device for a reversible rolling mill comprising an edger having a pair of edger rolls for performing width rolling on a material to be rolled, and a horizontal rolling mill disposed downstream of the edger and having a pair of horizontal rolls for performing horizontal rolling on the material to be rolled, a roll gap control device configured to operate the edger so that the pair of edger rolls come into contact with the material to be rolled during reverse pass rolling in which only the horizontal rolling by the horizontal rolling mill is performed without performing the width rolling by the edger; a roll gap position detector configured to detect the roll gap position of the edger when the pair of edger rolls are in contact with the material to be rolled during the reverse pass rolling; a tracking device configured to track the position in the longitudinal direction of the material to be rolled during the reverse pass rolling; a plate width actual value calculator configured to calculate plate width actual values at a plurality of positions in the longitudinal direction of the material to be rolled based on the output of the roll gap position detector and the output of the tracking device, and the roll gap control device, during the reverse pass rolling, operates the edger so as to reduce the distance between the pair of edger rolls from a state where the pair of edger rolls are not in contact with the material to be rolled; monitors the load measurement value of the edger, and detects that the load measurement value has reached a load target value as contact of the pair of edger rolls with the material to be rolled; and when contact of the pair of edger rolls with the material to be rolled is detected, operates the edger so as to increase the distance between the pair of edger rolls, and repeats the above operations. A plate width control device for a reversible rolling mill, characterized in the above.

2. In a plate width control device for a reversible rolling mill comprising an edger having a pair of edger rolls for performing width rolling on a material to be rolled, and a horizontal rolling mill disposed downstream of the edger and having a pair of horizontal rolls for performing horizontal rolling on the material to be rolled, a roll gap control device configured to operate the edger so that the pair of edger rolls come into contact with the material to be rolled during reverse pass rolling in which only the horizontal rolling by the horizontal rolling mill is performed without performing the width rolling by the edger; a roll gap position detector configured to detect the roll gap position of the edger when the pair of edger rolls are in contact with the material to be rolled during the reverse pass rolling; A tracking device configured to track the position of the material to be rolled in the longitudinal direction during the reverse-pass rolling; A measured plate width value calculator configured to calculate measured plate width values at a plurality of positions in the longitudinal direction of the material to be rolled based on the output of the roll gap position detector and the output of the tracking device; A plate width meter disposed downstream of the edger and configured to measure the plate width of the material to be rolled during forward-pass rolling before the reverse-pass rolling; and The measured plate width value calculator is configured to correct the measured plate width value using the plate width predicted from the measured value of the plate width meter and the amount of width spread due to the horizontal rolling. A plate width control device for a reversing rolling mill, characterized by the above.

3. In a plate width control device for a reversing rolling mill including an edger having a pair of edger rolls for performing width rolling on a material to be rolled and a horizontal rolling mill having a pair of horizontal rolls disposed downstream of the edger for performing horizontal rolling on the material to be rolled, A roll gap control device configured to operate the edger so that the pair of edger rolls contact the material to be rolled during reverse-pass rolling in which only the horizontal rolling by the horizontal rolling mill is performed without performing the width rolling by the edger; A roll gap position detector configured to detect the roll gap position of the edger when the pair of edger rolls are in contact with the material to be rolled during the reverse-pass rolling; A tracking device configured to track the position of the material to be rolled in the longitudinal direction during the reverse-pass rolling; A measured plate width value calculator configured to calculate measured plate width values at a plurality of positions in the longitudinal direction of the material to be rolled based on the output of the roll gap position detector and the output of the tracking device; A plate width meter disposed upstream of the edger and configured to measure the plate width of the material to be rolled during the reverse-pass rolling; and The measured plate width value calculator is configured to correct the measured plate width value using the measured value of the plate width meter. A plate width control device for a reversing rolling mill, characterized by the above.

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