STRIP WIDTH CONTROLLER FOR REVERSIBLE ROLLING MILL

Abstract

A strip width controller for a reversible rolling mill includes a rolling controller, a rolling position detector, a tracker, and a calculator. The rolling controller operates an edger so that a pair of edger rolls comes into contact with a strip to be rolled during reverse pass rolling. The rolling position detector detects a rolling position of the edger when the pair of edger rolls are in contact with the strip to be rolled during the reverse pass rolling. The tracker tracks a longitudinal position of the strip to be rolled during the reverse pass rolling. The calculator calculates strip width result values at a plurality of positions in the longitudinal direction of the strip to be rolled based on an output of the rolling position detector and an output of the tracker.

Claims

1. (canceled)

2. (canceled)

3. A strip width controller for a reversible rolling mill comprising an edger having a pair of edger rolls for width-rolling a strip to be rolled and a horizontal rolling mill having a pair of horizontal rolls disposed downstream of the edger for horizontal-rolling the strip to be rolled, the strip width controller comprising: a rolling controller configured to operate the edger so that the pair of edger rolls comes into contact with the strip to be rolled during reverse pass rolling; a rolling position detector configured to detect a rolling position of the edger when the pair of edger rolls are in contact with the strip to be rolled during the reverse pass rolling; a tracker configured to track a longitudinal position of the strip to be rolled during the reverse pass rolling; and a strip width result calculator configured to calculate strip width result values at a plurality of positions in a longitudinal direction of the strip to be rolled based on an output of the rolling position detector and an output of the tracker, wherein the rolling controller is configured to repeatedly execute: operating the edger so as to reduce a distance between the pair of edger rolls from a state in which the pair of edger rolls are not in contact with the strip to be rolled, monitoring a load measurement value of the edger to detect that the load measurement value reaches a load target value as contact of the pair of edger rolls with the strip to be rolled, and operating the edger to increase the distance between the pair of edger rolls when contact of the pair of edger rolls with the strip to be rolled is detected.

4. A strip width controller for a reversible rolling mill comprising an edger having a pair of edger rolls for width-rolling a strip to be rolled and a horizontal rolling mill having a pair of horizontal rolls disposed downstream of the edger for horizontal-rolling the strip to be rolled, the strip width controller comprising: a rolling controller configured to operate the edger so that the pair of edger rolls comes into contact with the strip to be rolled during reverse pass rolling; a rolling position detector configured to detect a rolling position of the edger when the pair of edger rolls are in contact with the strip to be rolled during the reverse pass rolling; a tracker configured to track a longitudinal position of the strip to be rolled during the reverse pass rolling; a strip width result calculator configured to calculate strip width result values at a plurality of positions in a longitudinal direction of the strip to be rolled based on an output of the rolling position detector and an output of the tracker; and a strip width meter disposed downstream of the edger and configured to measure a strip width of the strip to be rolled, wherein the strip width result calculator is configured to correct the strip width result value using a strip width predicted from a measured value of the strip width meter and a width spread amount by horizontal rolling.

5. A strip width controller for a reversible rolling mill comprising an edger having a pair of edger rolls for width-rolling a strip to be rolled and a horizontal rolling mill having a pair of horizontal rolls disposed downstream of the edger for horizontal-rolling the strip to be rolled, the strip width controller comprising: a rolling controller configured to operate the edger so that the pair of edger rolls comes into contact with the strip to be rolled during reverse pass rolling; a rolling position detector configured to detect a rolling position of the edger when the pair of edger rolls are in contact with the strip to be rolled during the reverse pass rolling; a tracker configured to track a longitudinal position of the strip to be rolled during the reverse pass rolling; a strip width result calculator configured to calculate strip width result values at a plurality of positions in a longitudinal direction of the strip to be rolled based on an output of the rolling position detector and an output of the tracker; and a strip width meter disposed upstream of the edger and configured to measure a strip width of the strip to be rolled, wherein the strip width result calculator is configured to correct the strip width result value using a measured value of the strip width meter.

6. The strip width controller for a reversible rolling mill according to claim 4, further comprising a rolling position correction calculator configured to calibrate an error of a gap between the pair of edger rolls based on the strip width result value corrected using the strip width predicted from the measured value of the strip width meter and the width spread amount by the horizontal rolling.

7. The strip width controller for a reversible rolling mill according to claim 5, further comprising a rolling position correction calculator configured to calibrate an error of a gap between the pair of edger rolls based on the strip width result value corrected using the measured value of the strip width meter.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0013] FIG. 1 is a diagram illustrating a configuration of a strip width controller according to a first embodiment of the present disclosure and a reversible rolling mill to which the strip width controller is applied, and processing during reverse pass rolling by the strip width controller.

[0014] FIG. 2 is a diagram showing operation of edger rolls during reverse pass rolling according to the first embodiment of the present disclosure.

[0015] FIG. 3 is a diagram illustrating the configuration of the strip width controller according to the first embodiment of the present disclosure and the reversible rolling mill to which the strip width controller is applied, and processing during forward pass rolling by the strip width controller.

[0016] FIG. 4 is a diagram illustrating a configuration of a first modification of the strip width controller according to the first embodiment of the present disclosure and a process during reverse pass rolling by the strip width controller.

[0017] FIG. 5 is a diagram illustrating a configuration of a second modification of the strip width controller according to the first embodiment of the present disclosure and a process during reverse pass rolling by the strip width controller.

[0018] FIG. 6 is a diagram showing operation of edger rolls during reverse pass rolling according to a second embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

1. First Embodiment

1-1. Configuration of Reversible Rolling Mill

[0019] Hereinafter, a configuration of a reversible rolling mill 10 according to a first embodiment of the present disclosure will be described with reference to FIG. 1.

[0020] The reversible rolling mill 10 includes a roller table 80 for conveying a strip to be rolled (slab) 90. The roller table 80 has a plurality of rollers which can be driven in a forward direction and a reverse direction. A speed detector 81 for detecting the conveying speed of the roller table 80 is attached to the roller table 80. The reversible rolling mill 10 is provided with an edger 20 for width rolling and a horizontal rolling mill 30 for horizontal rolling on a conveying line of the strip to be rolled 90 by a roller table 80. The horizontal rolling mill 30 is disposed downstream of the edger 20 on the conveying line.

[0021] The edger 20 includes a pair of edger rolls 25 arranged so as to sandwich the strip to be rolled 90 from the left and right. The edger rolls 25 are supported by roll chocks 26, i.e., axle boxes with bearings. The edger 20 includes a rolling apparatus 22 that moves edger rolls 25 supported by roll chocks 26 in the width direction of the strip to be rolled 90. The rolling apparatus 22 includes a hydraulic cylinder, and a high-speed rolling operation can be performed by the hydraulic cylinder.

[0022] The edger 20 is provided with a load indicator 24 for detecting the roll load by the rolling apparatus 22. The load indicator 24 is, in particular, a load cell provided on the roll chock 26. However, an oil pressure detector provided in the hydraulic cylinder of the rolling apparatus 22 can also be used as the load indicator 24. The edger 20 also includes a rolling position detector 23 that detects a rolling position by the rolling apparatus 22. The rolling position detector 23 outputs an oil column length of the hydraulic cylinder as a detected value of the rolling position. Here, the rolling position is a value indicating the gap between the pair of edger rolls 25 when no load is applied (when rolling is not performed). The rolling position detector 23 calculates and outputs a rolling position based on actual measurement values of the oil column lengths of the hydraulic cylinders on both sides. For example, the actual gap between the edger rolls 25 is measured in advance at a certain reference oil column length (this processing is called zero adjustment), and a value obtained by subtracting the amount of change in the oil column length from the time of zero adjustment from the measured value (zero adjustment roll gap) is output as the detected value of the rolling position.

[0023] The horizontal rolling mill 30 includes a pair of horizontal rolls 31 arranged so as to sandwich the strip 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. A hot metal detector (HMD) 100 is disposed on the exit side of the horizontal rolling mill 30. However, the number of the hot metal detector 100 disposed on the reversible rolling mill 10 is not one, but the hot metal detectors 100 are arranged at a plurality of positions on the conveying line of the strip to be rolled 90.

1-2. Configuration of Strip Width Controller

[0024] Next, a configuration of a strip width controller 200 applied to the reversible rolling mill 10 configured as described above will be described with reference to FIG. 1.

[0025] The strip width controller 200 is composed of a rolling controller 21, a strip width result calculator 40, a setting calculator 50, a rolling position correction calculator 60, and a tracker 70. These devices 21, 40, 50, 60, 70 that constitute the strip width controller 200 may be application specific integrated circuits (ASIC), field programmable gate arrays (FPGA), central processing unit (CPUs), or other processing devices. One or more of the devices 21, 40, 50, 60, 70 may be a combination of two or more ASIC, FPGA, CPU, or other processing devices. The ASIC, FPGA, CPUs, and other processing devices that constitute the strip width controller 200 include a series of executable instructions. When executed, these instructions trigger the corresponding ASIC, FPGA, CPU, and other processing devices to perform the functions of the respective devices 21, 40, 50, 60, 70.

[0026] The setting calculator 50 is configured to give various setting calculation values 51 to the rolling controller 21. The setting calculation value 51 includes a load target value 51a for the strip to be rolled 90. The load target value 51a is a value determined in advance in a range from the minimum load to the maximum load. The minimum load is a lower limit value at which the load can be stably measured, and the maximum load is a mechanical allowable upper limit value of the edger 20.

[0027] The rolling controller 21 operates in accordance with various setting calculation values 51 given from the setting calculator 50. Further, a roll load detected by the load indicator 24 and a roll position detected by the roll position detector 23 are input to the rolling controller 21. The rolling controller 21 is configured to transmit a detected value of the rolling position input from the rolling position detector 23 to the strip width result calculator 40 as a rolling position result value 21a.

[0028] The tracker 70 acquires a rotation speed of the horizontal roll 31 detected by the speed detector 32, a conveyance speed of the roller table 80 detected by the speed detector 81, and an output of the hot metal detector 100. The tracker 70 is configured to generate tracking information 71 indicating the position of the strip to be rolled 90 in the longitudinal direction using the information acquired during the reverse pass rolling. The generated tracking information 71 is transmitted to the strip width result calculator 40.

[0029] The strip width result calculator 40 includes a storage unit 41 and a full-length strip width result calculation unit 42. The rolling position result value 21a transmitted from the rolling controller 21 is stored in the storage unit 41. The tracking information 71 generated by the tracker 70 is also stored in the storage unit 41. Both the rolling position result value 21a and the tracking information 71 are information acquired during the reverse pass rolling of the strip to be rolled 90, and are associated with each other by the acquired timing. The timing of acquiring these pieces of information is determined in advance by a constant or variable sampling time interval or the position of the strip to be rolled 90 in the longitudinal direction.

[0030] The full-length strip width result calculation unit 42 is configured to calculate result values of the width of the strip to be rolled 90 at a plurality of positions in the longitudinal direction based on the information stored in the storage unit 41. The method of calculating the result value of the strip width will be described in detail later. The result value of the strip width calculated by the full-length strip width result calculation unit 42 is input to the rolling position correction calculator.

[0031] The rolling position correction calculator 60 is configured to calculate the amount of correction of the rolling position by the rolling apparatus 22 based on the result value of the strip width calculated by the full-length strip width result calculation unit 42. The amount of correction of the rolling position calculated by the rolling position correction calculator 60 is used for control of the edger 20 by the rolling controller 21 in the next forward pass rolling after the reverse pass rolling in which the result value of the strip width has been calculated. The method of calculating the amount of correction of the rolling position will be described later.

1-3. Processing During Reverse Pass Rolling of Strip Width Controller

[0032] In the reverse pass rolling, the strip to be rolled 90 is conveyed in the direction of the arrow by the roller table 80, and during this time, the strip to be rolled 90 is sandwiched from the left and right by the pair of edger rolls 25. During the reverse pass rolling, the constant load control is applied to the edger 20 by the rolling controller 21. In the constant load control, the rolling apparatus 22 is operated so that the roll load detected by the load indicator 24 coincides with the load target value 51a.

[0033] FIG. 2 is a view showing the operation of the edger rolls 25 during the reverse pass rolling. By performing the 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 and the strip to be rolled 90 are in contact with each other is maintained over the entire length of the strip to be rolled 90. Then, while the edger rolls 25 are relatively moving along the side surface of the strip to be rolled 90, the rolling position result value 21a corresponding to the width direction position of the edger rolls 25 is acquired by the rolling position detector 23.

[0034] After the reverse pass rolling is finished, the calculation of the strip width result value of the strip to be rolled 90 is performed by the strip width result calculator 40. The calculation of the strip width result value is performed by the full-length strip width result calculation unit 42. The full-length strip width result calculation unit 42 calculates the strip width result value over the full length by the following formula using the rolling position result value 21a stored in the storage unit 41.

[00001]$\begin{array}{cc}{B}_{i-1}^{\mathrm{CFR}}\left(j\right)=S_{\mathrm{Ei}-1}^{\mathrm{ACT}}\left(j\right)+S_{\mathrm{mEi}-1}+S_{\mathrm{weari}-1}-S_{\mathrm{thermi}-1}& \left[\mathrm{Formula}1\right]\end{array}$

The meanings of the parameters in the above formula are as follows.

[00002]$\begin{array}{cc}{B}_{i-1}^{\mathrm{CFR}}\left(j\right):\mathrm{Strip}\mathrm{width}\mathrm{result}\mathrm{value}\left[\mathrm{mm}\right]\mathrm{of}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)\mathrm{at}\mathrm{longitudinal}\mathrm{position}j& \left[\mathrm{Formula}2\right]\end{array}$$\begin{array}{cc}{S}_{\mathrm{Ei}-1}^{\mathrm{ACT}}\left(j\right):\mathrm{Rolling}\mathrm{position}\mathrm{result}\mathrm{value}\left[\mathrm{mm}\right]\mathrm{of}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)\mathrm{at}\mathrm{longitudinal}\mathrm{direction}\mathrm{position}j& \left[\mathrm{Formula}3\right]\end{array}$$\begin{array}{cc}{S}_{\mathrm{mEi}-1}:\mathrm{Edger}\mathrm{mill}\mathrm{elongation}\mathrm{amount}\left[\mathrm{mm}\right]\mathrm{of}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)& \left[\mathrm{Formula}4\right]\end{array}$$\begin{array}{cc}{S}_{\mathrm{weari}-1}:\mathrm{Edger}\mathrm{roll}\mathrm{wear}\mathrm{amount}\left[\mathrm{mm}\right]\mathrm{of}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)& \left[\mathrm{Formula}5\right]\end{array}$$\begin{array}{cc}{S}_{\mathrm{thermi}-1}:\mathrm{Edger}\mathrm{roll}\mathrm{thermal}\mathrm{expansion}\mathrm{amount}\left[\mathrm{mm}\right]\mathrm{of}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)& \left[\mathrm{Formula}6\right]\end{array}$

[0035] An edger mill elongation amount is calculated from the rolling load using a mill curve expressed as a quadratic formula or the like. A wear amount and a thermal expansion amount of the edger roll are considered as a change from the edger roll diameter at zero adjustment. The wear amount is periodically calculated and integrated at a cycle of several seconds from the rolling load, the rolling length, and the like which are predicted or measured. The thermal expansion amount is periodically calculated and integrated at a cycle of several seconds from the predicted or measured roll temperature. The thermal expansion amount is periodically calculated and integrated at a cycle of several seconds from the predicted or measured roll temperature. When the edger roll is worn, the wear amount is a positive value, and when the edger roll is thermally expanded, the thermal expansion amount is a positive value.

[0036] In the present embodiment, during the reverse pass rolling, the state in which the edger rolls 25 and the strip to be rolled 90 are in contact with each other is maintained by the constant load control. Therefore, the rolling position result value 21a can be acquired at any position in the longitudinal direction. In order to acquire the strip width result value over the full length with high accuracy, the number of measurement points for acquiring the rolling position result value 21a and the tracking information 71 is preferably as large as possible.

[0037] In the present embodiment, the load target value 51a of the constant load control is set to a sufficiently small value within a range in which the load can be stably measured. By doing so, the amount of width rolling in the reverse pass rolling can be kept small, and the occurrence of dog bones in the strip to be rolled 90 and the width variation (plastic deformation) due to the width return can be made negligibly small. As a result, the strip width result value over the full length, particularly the strip width result value at the leading and trailing end portions can be acquired with high accuracy.

[0038] As described above, in the present embodiment, the strip width result value over the full length of the strip to be rolled 90 is calculated based on the rolling position of the edger 20 acquired by the constant load control during the reverse pass rolling and the position in the longitudinal direction of the strip to be rolled 90 tracked during the reverse pass rolling. According to this, it is not necessary to convey the strip to be rolled 90 by a distance equal to or more than that required for reverse pass rolling. Therefore, according to the strip width controller 200 of the present embodiment, the strip width of the strip to be rolled 90 can be acquired over the full length while avoiding a decrease in production due to time loss.

1-4. Processing During Forward Pass Rolling of Strip Width Controller

[0039] The forward pass rolling is performed after the reverse pass rolling. FIG. 3 shows the processing during the forward pass rolling by the strip width controller 200. In the forward pass rolling, the strip to be rolled 90 is conveyed in the direction of the arrow by the roller table 80, and during this time, the strip to be rolled 90 is rolled from the left and right by the edger 20. The rolling of the strip to be rolled 90 by the edger 20 is performed so that the strip width at the end of the forward pass rolling is constant over the entire length.

[0040] Before the start of the forward pass rolling, the correction amount of the rolling position of the edger 20 is calculated by the rolling position correction calculator 60. The correction amount of the rolling position is calculated by using the strip width result value over the full length calculated at the time of reverse pass rolling. The correction amount of the rolling position may be calculated for each position in the longitudinal direction in accordance with the distribution of the strip width result value in the longitudinal direction, or the correction amount of the rolling position for the entire longitudinal direction may be calculated based on the average value of the strip width result value in the longitudinal direction. The following formula is an example of a formula for calculating the amount of correction of the rolling position.

[00003]$\begin{array}{cc}{S}_i\left(j\right)=-\frac{B_{i-1}\left(j\right)}{{}_i}.Math.G_i& \left[\mathrm{Formula}7\right]\end{array}$$\begin{array}{cc}{B}_{i-1}\left(j\right)-B_{i-1}^{\mathrm{CFR}}\left(j\right)-B_{i-1}^{\mathrm{ref}}& \left[\mathrm{Formula}8\right]\end{array}$$\begin{array}{cc}{B}_{i-1}^{\mathrm{ref}}=\frac{1}{L_{\mathrm{end}}-L_{\mathrm{start}}}{}_{j=L_{\mathrm{start}}}^{L_{\mathrm{end}}}{B}_{i-1}^{\mathrm{CFR}}\left(j\right)\mathrm{dj}& \left[\mathrm{Formula}9\right]\end{array}$

The meanings of the parameters in the above formula are as follows.

[00004]$\begin{array}{cc}{S}_i\left(j\right):\mathrm{Edger}\mathrm{rolling}\mathrm{position}\mathrm{correction}\mathrm{amount}\left[\mathrm{mm}\right]\mathrm{of}i\mathrm{pass}\mathrm{at}\mathrm{longitudinal}\mathrm{direction}\mathrm{position}j& \left[\mathrm{Formula}10\right]\end{array}$$\begin{array}{cc}{B}_{i-1}\left(j\right):\mathrm{Deviation}\left[\mathrm{mm}\right]\mathrm{from}\mathrm{reference}\mathrm{width}\mathrm{of}i-1\mathrm{pass}\mathrm{at}\mathrm{longitudinal}\mathrm{position}j& \left[\mathrm{Formula}11\right]\end{array}$$\begin{array}{cc}{}_i:\mathrm{Edger}\mathrm{rolling}\mathrm{efficiency}[-]\mathrm{in}i\mathrm{pass}& \left[\mathrm{Formula}12\right]\end{array}$$\begin{array}{cc}{G}_i:\mathrm{Rolling}\mathrm{position}\mathrm{correction}\mathrm{gain}[-]\mathrm{in}i\mathrm{pass}& \left[\mathrm{Formula}13\right]\end{array}$$\begin{array}{cc}{B}_{i-1}^{\mathrm{CFR}}\left(j\right):\mathrm{Strip}\mathrm{width}\mathrm{result}\mathrm{value}\left[\mathrm{mm}\right]\mathrm{of}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)\mathrm{at}\mathrm{longitudinal}\mathrm{position}j& \left[\mathrm{Formula}14\right]\end{array}$$\begin{array}{cc}{B}_{i-1}^{\mathrm{ref}}:\mathrm{Strip}\mathrm{width}\mathrm{reference}\mathrm{value}\left[\mathrm{mm}\right]\mathrm{of}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)& \left[\mathrm{Formula}15\right]\end{array}$$\begin{array}{cc}{L}_{\mathrm{start}}:\mathrm{Average}\mathrm{section}\mathrm{start}\mathrm{position}\left[m\right]& \left[\mathrm{Formula}16\right]\end{array}$$\begin{array}{cc}{L}_{\mathrm{end}}:\mathrm{Average}\mathrm{section}\mathrm{end}\mathrm{position}\left[m\right]& \left[\mathrm{Formula}17\right]\end{array}$

[0041] The edger rolling efficiency is expressed by a function of the strip thickness/strip width ratio, and usually takes a value of about 0.2 to 0.8. As the strip width reference value of the reverse pass (i1 pass), the average value of the strip width result value in a predetermined section is used. However, a calculated value for setting the strip width may be used instead of the average value.

[0042] The rolling position correction calculator 60 inputs the edger rolling position correction amount 61 calculated by the above formula to the rolling controller 21. The edger rolling position correction amount 61 is calculated for each position in the longitudinal direction in accordance with the distribution of the strip width result value in the longitudinal direction. The setting calculator 50 inputs the load target value 51a to the rolling controller 21. The rolling controller 21 controls the gap between the edger rolls 25 by matching the timing between the input information and the tracking information 71 input from the tracker 70. Thus, the width accuracy of the strip to be rolled 90 which is sent to the downstream finishing rolling process is improved, and the yield of the product is improved.

1-5. Configuration of First Modification of Strip Width Controller and Processing for Correcting Strip Width Result Value

[0043] FIG. 4 shows a first modification of the strip width controller 200. In the first modification, the strip width controller 200 includes a strip width meter 110 downstream of the reversible rolling mill 10. The strip width result calculator 40 of the strip width controller 200 is constituted by a storage unit 41, a full-length strip width result calculation unit 42, and a strip width result correction unit 43.

[0044] In the first modification, during forward pass rolling before reverse pass rolling, the strip to be rolled 90 which has passed through the horizontal rolling mill 30 reaches the strip width meter 110, and the strip width thereof is measured. However, after it is confirmed that the rear end of the strip to be rolled 90 (the rear end in the traveling direction of the rolling line) 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, the strip width is not measured over the full length of the strip to be rolled 90, but only the strip width of the leading end portion 91 which has reached the strip width meter 110 before the trailing end of the strip to be rolled 90 passes through the horizontal rolling mill 30 is measured. The measured value of strip width 111 obtained by the strip width meter 110 is transmitted to the strip width result calculator 40 and stored in the storage unit 41.

[0045] In the first modification, the strip width result value over the full length obtained by the full-length strip width result calculation unit 42 is corrected by the strip width result correction unit 43. The correction amount of the strip width result value is calculated by the following formula using the width measurement value obtained by the strip width meter 110 during the forward pass rolling.

[00005]$\begin{array}{cc}{B}_{i-1}^{\mathrm{corr},\mathrm{CFR}}\left(j\right)=B_{i-1}^{\mathrm{CFR}}\left(j\right)+B_{i-1}^{\mathrm{corr}}& \left[\mathrm{Formula}18\right]\end{array}$$\begin{array}{cc}{B}_{i-1}^{\mathrm{corr}}=\frac{1}{L_{\mathrm{end}}^{\mathrm{corr}}-L_{\mathrm{start}}^{\mathrm{corr}}}{}_{j=L_{\mathrm{start}}^{\mathrm{corr}}}^{L_{\mathrm{end}}^{\mathrm{corr}}}\left(B_{i-1}^{\mathrm{pre}}\left(j\right)-B_{i-1}^{\mathrm{CFR}}\left(j\right)\right)\mathrm{dj}& \left[\mathrm{Formula}19\right]\end{array}$$\begin{array}{cc}{B}_{i-1}^{\mathrm{pre}}\left(j^{}\right)=B_{i-2}^{\mathrm{RDW}}\left(j\right)+B_{i-1}^{\mathrm{spread}}& \left[\mathrm{Formula}20\right]\end{array}$$\begin{array}{cc}{j}^{}=j.Math.{}_{i-1}& \left[\mathrm{Formula}21\right]\end{array}$$\begin{array}{cc}{}_{i-1}\frac{h_{i-2}}{h_{i-1}}& \left[\mathrm{Formula}22\right]\end{array}$

The meanings of the parameters in the above formula are as follows.

[00006]$\begin{array}{cc}{B}_{i-1}^{{\mathrm{corr}}_{\mathrm{CFR}}}\left(j\right):\mathrm{Strip}\mathrm{width}\mathrm{result}\mathrm{value}\left[\mathrm{mm}\right]\mathrm{of}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)\mathrm{after}\mathrm{correction}\mathrm{at}\mathrm{longitudinal}\mathrm{direction}\mathrm{position}j& \left[\mathrm{Formula}23\right]\end{array}$$\begin{array}{cc}{B}_{i-1}^{\mathrm{corr}}:\mathrm{Strip}\mathrm{width}\mathrm{result}\mathrm{value}\mathrm{correction}\mathrm{amount}\left[\mathrm{mm}\right]& \left[\mathrm{Formula}24\right]\end{array}$$\begin{array}{cc}{L}_{\mathrm{start}}^{\mathrm{corr}}:\mathrm{Longitudinal}\mathrm{position}\left[m\right]\mathrm{of}\mathrm{strip}\mathrm{material}\mathrm{to}\mathrm{be}\mathrm{rolled}\mathrm{to}\mathrm{start}\mathrm{calculating}\mathrm{correction}\mathrm{amount}& \left[\mathrm{Formula}25\right]\end{array}$$\begin{array}{cc}{L}_{\mathrm{start}}^{\mathrm{means}}:\mathrm{Longitudinal}\mathrm{position}\left[m\right]\mathrm{of}\mathrm{start}\mathrm{point}\mathrm{of}\mathrm{section}\mathrm{in}\mathrm{which}\mathrm{sheet}\mathrm{width}\mathrm{was}\mathrm{measured}\left(L_{\mathrm{start}}^{\mathrm{corr}}{L}_{\mathrm{start}}^{\mathrm{meas}}\right)& \left[\mathrm{Formula}26\right]\end{array}$$\begin{array}{cc}{L}_{\mathrm{end}}^{\mathrm{corr}}:\mathrm{Longitudinal}\mathrm{position}\left[m\right]\mathrm{of}\mathrm{strip}\mathrm{material}\mathrm{to}\mathrm{be}\mathrm{rolled}\mathrm{to}\mathrm{end}\mathrm{calculating}\mathrm{correction}\mathrm{amount}& \left[\mathrm{Formula}27\right]\end{array}$$\begin{array}{cc}{L}_{\mathrm{end}}^{\mathrm{means}}:\mathrm{Longitudinal}\mathrm{position}\left[m\right]\mathrm{of}\mathrm{end}\mathrm{point}\mathrm{of}\mathrm{section}\mathrm{in}\mathrm{which}\mathrm{sheet}\mathrm{width}\mathrm{was}\mathrm{measured}\left(L_{\mathrm{end}}^{\mathrm{corr}}{L}_{\mathrm{end}}^{\mathrm{meas}}\right)& \left[\mathrm{Formula}28\right]\end{array}$$\begin{array}{cc}{B}_{i-1}^{\mathrm{pre}}\left(j\right):\mathrm{Strip}\mathrm{width}\left[\mathrm{mm}\right]\mathrm{after}\mathrm{end}\mathrm{of}\mathrm{reverse}\mathrm{pass}\mathrm{predicted}\mathrm{from}\mathrm{strip}\mathrm{width}\mathrm{meter}\mathrm{measurement}\mathrm{value}\mathrm{at}\mathrm{longitudinal}\mathrm{direction}\mathrm{position}j& \left[\mathrm{Formula}29\right]\end{array}$$\begin{array}{cc}{B}_{i-2}^{\mathrm{RDW}}\left(j\right):\mathrm{Strip}\mathrm{width}\mathrm{measurement}\mathrm{value}\left[m\right]\mathrm{on}\mathrm{exit}\mathrm{side}\mathrm{of}\mathrm{rolling}\mathrm{mill}\mathrm{of}\mathrm{forward}\mathrm{pass}\left(i-2\mathrm{pass}\right)\mathrm{at}\mathrm{longitudinal}\mathrm{position}j& \left[\mathrm{Formula}30\right]\end{array}$$\mathrm{Here},j\mathrm{satisfies}\mathrm{the}\mathrm{following}\mathrm{condition}.$$\begin{array}{cc}{L}_{\mathrm{start}}^{\mathrm{meas}}j{L}_{\mathrm{end}}^{\mathrm{meas}}& \left[\mathrm{Formula}31\right]\end{array}$$\begin{array}{cc}{B}_{i-1}^{\mathrm{spread}}:\mathrm{Predicted}\mathrm{value}\left[\mathrm{mm}\right]\mathrm{of}\mathrm{width}\mathrm{expansion}\mathrm{amount}\mathrm{by}\mathrm{horizontal}\mathrm{rolling}\mathrm{in}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)& \left[\mathrm{Formula}32\right]\end{array}$$\begin{array}{cc}{j}^{}:\mathrm{Position}\left[\mathrm{mm}\right]\mathrm{in}\mathrm{consideration}\mathrm{of}\mathrm{elongation}\mathrm{in}\mathrm{longitudinal}\mathrm{direction}\mathrm{by}\mathrm{horizontal}\mathrm{rolling}\mathrm{in}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{Pass}\right)& \left[\mathrm{Formula}33\right]\end{array}$$\begin{array}{cc}{}_{i-1}:\mathrm{Elongation}\mathrm{ratio}\left[m\right]\mathrm{in}\mathrm{longitudinal}\mathrm{direction}\mathrm{by}\mathrm{horizontal}\mathrm{rolling}\mathrm{in}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)& \left[\mathrm{Formula}34\right]\end{array}$$\begin{array}{cc}{h}_{i-2}:\mathrm{Strip}\mathrm{thickness}\left[\mathrm{mm}\right]\mathrm{on}\mathrm{exit}\mathrm{side}\mathrm{of}\mathrm{forward}\mathrm{pass}\left(i-2\mathrm{pass}\right)& \left[\mathrm{Formula}35\right]\end{array}$$\begin{array}{cc}{h}_{i-1}:\mathrm{Strip}\mathrm{thickness}\left[\mathrm{mm}\right]\mathrm{on}\mathrm{exit}\mathrm{side}\mathrm{of}\mathrm{reverse}\mathrm{pass}\left(i-1\mathrm{pass}\right)& \left[\mathrm{Formula}36\right]\end{array}$

[0046] In general, the strip width meter 110 downstream of the reversible rolling mill 10 is often installed at a position away from the reversible rolling mill 10 by about 5 m or more in order to avoid measurement disturbance due to roll cooling water or the like. When the reverse pass rolling is performed after the forward pass rolling, the rolling is quickly switched to the reverse pass rolling after the forward pass rolling is finished. Therefore, a section which cannot be measured by the strip width meter 110 downstream of the reversible rolling mill 10 (a section corresponding to the distance from the horizontal rolling mill 30 to the strip width meter 110) is generated. The correction amount of the strip width result value can be calculated in an arbitrary section within the section in which the strip width measurement value can be measured.

1-6. Configuration of Second Modification of Strip Width Controller and Processing for Correcting Strip Width Result Value

[0047] FIG. 5 shows a second modification of the strip width controller 200. In the second modification, the strip width controller 200 includes a strip width meter 110 upstream of the reversible rolling mill 10. The strip width result calculator 40 of the strip width controller 200 is constituted by a storage unit 41, a full-length strip width result calculation unit 42, and a strip width result correction unit 43.

[0048] In the second modification, during reverse pass rolling, the strip to be rolled 90 that has passed through the edger 20 reaches the strip width meter 110, and the strip width thereof is measured. However, after it is confirmed that the leading end of the strip to be rolled 90 (the leading end in the traveling direction of the rolling line) has passed through the horizontal rolling mill 30, the conveying direction of the roller table 80 is promptly switched from the reverse pass to the forward pass. Therefore, the strip width is not measured over the full length of the strip to be rolled 90, but only the strip width of the rear end portion 92 which has reached the strip width meter 110 before the front end of the strip to be rolled 90 passes through the edger 20 is measured. The measured value of strip width 111 obtained by the strip width meter 110 is transmitted to the strip width result calculator 40 and stored in the storage unit 41.

[0049] In the second modification, the strip width result value over the full length obtained by the full-length strip width result calculation unit 42 is corrected by the strip width result correction unit 43. The correction amount of the strip width result value is calculated by the following formula using the width measurement value obtained by the strip width meter 110 during the reverse pass rolling.

[00007]$\begin{array}{cc}{B}_{i-1}^{\mathrm{corr\_CFR}}\left(j\right)=B_{i-1}^{\mathrm{CFR}}\left(j\right)+B_{i-1}^{\mathrm{corr}}& \left[\mathrm{Formula}37\right]\end{array}$$\begin{array}{cc}{B}_{i-1}^{\mathrm{corr}}=\frac{1}{L_{\mathrm{end}}^{\mathrm{corr}}-L_{\mathrm{start}}^{\mathrm{corr}}}{}_{j=L_{\mathrm{start}}^{\mathrm{corr}}}^{L_{\mathrm{end}}^{\mathrm{corr}}}\left(B_{i-1}^{\mathrm{REW}}\left(j\right)-B_{i-1}^{\mathrm{CFR}}\left(j\right)\right)\mathrm{dj}& \left[\mathrm{Formula}38\right]\end{array}$

The meanings of the parameters in the above formula are as follows. However, the description of the parameters common to the parameters of the formula according to the first modification will be omitted.

[00008]$\begin{array}{cc}{B}_{i-1}^{\mathrm{REW}}\left(j\right):\mathrm{Strip}\mathrm{width}\mathrm{measurement}\mathrm{value}\left[m\right]\mathrm{on}\mathrm{exit}\mathrm{side}\mathrm{of}\mathrm{rolling}\mathrm{mill}\mathrm{of}\mathrm{forward}\mathrm{pass}\left(i-2\mathrm{pass}\right)\mathrm{at}\mathrm{longitudinal}\mathrm{position}j& \left[\mathrm{Formula}39\right]\end{array}$

[0050] Generally, the strip width meter 110 upstream of the reversible rolling mill 10 is installed near the exit side of the upstream rolling mill. Since the rolling is quickly switched to the forward pass rolling after the reverse pass rolling, a section which cannot be measured by the strip width meter 110 upstream of the reversible rolling mill 10 (a section corresponding to a distance from the strip width meter 110 to the edger 20) is generated. The correction amount of the strip width result value can be calculated in an arbitrary section within the section in which the strip width measurement value can be measured.

[0051] In rolling equipment, zero adjustment is performed each time a roll is replaced or the equipment is stopped in order to improve dimensional accuracy by calibrating mechanical wear and a change in roll diameter which change with time. The horizontal rolling mill 30 can perform measurement by a method of bringing rolls into contact with each other (kiss roll), and thus can perform zero adjustment under a condition (load) close to actual rolling. On the other hand, since the pair of edger rolls 25 are at a distance apart from each other, the zero adjustment in which the rolls are brought 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 the edger roll gap by sandwiching a test material having a known dimension has been performed. However, in the indirect method, there is a case where the zero adjustment of the edger roll gap is not correctly performed due to a measurement error.

[0052] In this regard, according to the above-described strip width controller, errors in the edger roll gap due to inaccurate zero adjustment and prediction errors in roll wear can be calibrated, and highly accurate strip width result values can be acquired, and also the strip width rolling accuracy can be improved.

2. Second Embodiment

[0053] Next, a strip width controller according to a second embodiment of the present disclosure will be described. The strip width controller according to the present embodiment has a basic configuration common to the strip width controller according to the first embodiment. That is, the strip width controller according to the present embodiment has the configuration shown in FIG. 1 as in the first embodiment. The difference between the strip width controller according to the present embodiment and the strip width controller according to the first embodiment is in the control of the edger 20 by the rolling controller 21 performed during reverse pass rolling. Specifically, the operation of the edger rolls 25 controlled by the rolling controller 21 is different.

[0054] FIG. 6 is a view showing the operation of the edger rolls 25 during reverse pass rolling according to the present embodiment. The flow line shown by the broken line in FIG. 6 is a flow line showing the operation of the edger rolls 25 relative to the strip to be rolled 90, that is, the operation of the rolling position of the edger 20. In the second embodiment, a plurality of measurement points is predetermined in the longitudinal direction of the strip to be rolled 90, and the strip width result value is acquired for each measurement point. In the example shown in FIG. 6, the point at which the movement line is in contact with the strip to be rolled 90 is the measurement point at which the strip width result value is acquired. The measurement points are defined by a fixed or variable sampling time interval or length interval.

[0055] The rolling position of the edger 20 before the start of reverse pass rolling is a position where the edger rolls 25 do not contact the strip to be rolled 90. Then, it is detected from the tracking information 71 that the predetermined measurement point of the strip to be rolled 90 has reached the position of the edger rolls 25 (time t0).

[0056] Next, the edger 20 is operated in a direction to narrow the gap 28 between the edger rolls 25 (Operation 1). A rolling speed of the edger 20 at this time is determined in advance before the start of reverse pass rolling, in consideration of the response characteristics of the rolling apparatus 22 and the load indicator 24 and the control cycle of the rolling controller 21. Specifically, the rolling speed is a constant speed or a speed determined by the rolling position.

[0057] During the control of the rolling speed, the rolling load and the amount of change in the rolling load per unit time are monitored. When the edger rolls 25 come into contact with the strip to be rolled 90 and the roll load reaches the load target value (time t1), the rolling position of the edger 20 and the position of the strip to be rolled 90 in the longitudinal direction at that time are stored in the storage unit 41. The target load value is a value that is determined in advance within a range in which the load can be stably measured and the width rolling amount or the dog-bone-type swelling amount does not exceed an allowable upper limit.

[0058] The edger 20 is then 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 strip to be rolled 90 reaches the position of the edger rolls 25 (Operation 3).

[0059] In the first embodiment, the hydraulic cylinder of the rolling apparatus 22 is opened and closed by performing the constant load control, and the direction of the sliding friction of the hydraulic cylinder changes each time. When the oil pressure detector is used as the load indicator 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. Therefore, in the first embodiment, there is a possibility that the contact state between the strip to be rolled 90 and the edger rolls 25 cannot be equally maintained over the full length of the strip to be rolled 90.

[0060] In contrast, in the second embodiment, the direction of the operation of the hydraulic cylinder at the time of measuring the rolling position is always the direction of closing the gap 28 between the edger rolls 25. Therefore, the direction of the sliding friction of the hydraulic cylinders does not change, and the measurement conditions for measuring the rolling position are made constant. Therefore, according to the second embodiment, the accuracy of measuring the strip width of the strip to be rolled 90 can be further improved.

[0061] The method of correcting the strip width result value using the strip width measurement value described in the first modification and the second modification of the first embodiment can also be applied to the strip width controller according to the second embodiment.

DESCRIPTION OF SYMBOLS

[0062] 10 Reversible rolling mill [0063] 20 Edger [0064] 22 Rolling apparatus [0065] 21 Rolling controller [0066] 23 Rolling position detector [0067] 24 Load indicator [0068] 25 Edger roll [0069] 30 Horizontal rolling mill [0070] 40 Strip width result calculator [0071] 50 Setting calculator [0072] 60 Rolling position correction calculator [0073] 70 Tracker [0074] 31 Horizontal roll [0075] 90 Strip to be rolled [0076] 110 Strip width meter [0077] 200 Strip width controller