JP2015037802A - Meandering control device and meandering control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the occurrence of a rolling trouble of a metallic strip by stably controlling meandering of the continuously rolled metallic strip.SOLUTION: A meandering control device includes: tension measurement means for measuring each tension at one end and the other end of a width direction of a metallic strip on each rolling machine outlet side of a tandem rolling machine; arithmetic processing means for performing arithmetic processing of tension; and control means of reduction leveling amount. The arithmetic processing means calculates differential tension of each tension at the one end and the other end and total tension and calculates a tension rate of the differential tension to the total tension. The control means corrects a target range of the tension ratio of the metallic strip in the rolling machine to be a control object according to reduction leveling amount of the next rolling machine arranged side by side with a rear stage of the rolling machine to be the control object, and controls the reduction leveling amount of the rolling machine to be the control object so that the tension ratio of the metallic strip on the rolling machine outlet side to be the control object may be in the target range after the correction.

Description

  The present invention relates to a meandering control device and a meandering control method for controlling meandering of a metal strip continuously rolled by a plurality of rolling mills.

  2. Description of the Related Art Conventionally, a tandem rolling mill for continuously rolling a metal strip is installed in a rolling line for a metal strip such as a cold rolled steel sheet. Generally, a tandem rolling mill is constituted by a plurality of rolling mills arranged side by side along a metal strip conveyance path. When the number of rolling mills constituting the tandem rolling mill (hereinafter referred to as the number of stands) is n (n is an integer of 2 or more), the most upstream rolling mill of the tandem rolling mills is the rolling of the first stand. The most downstream rolling mill is an n-th stand rolling mill. Between the rolling mill of the first stand and the rolling mill of the n-th stand, the second stand, the third stand,..., The n-2 stand toward the metal strip conveyance direction (forward direction), The rolling mills of the (n-1) th stand are juxtaposed. In such a tandem rolling mill, the metal strips are continuously rolled in the order of the stand numbers of the respective rolling mills by the rolling mills of the first stand to the nth stand.

  Further, in order to prevent the meandering of the metal strip continuously rolled by the tandem rolling mill as described above, the reduction leveling amount of each rolling mill in the tandem rolling mill is conventionally used by using the differential tension of the metal strip. Is controlled. The differential tension is the difference between the tension at one end and the tension at the other end in the width direction of the metal strip (hereinafter referred to as the material width direction as appropriate). The reduction leveling amount is a difference in roll gap between a pair of rolling rolls (two work rolls) sandwiching a metal strip from both the front and back surfaces in a rolling mill. Specifically, it is the difference between the roll gap at one end and the roll gap at the other end in the width direction of these two work rolls (hereinafter referred to as the roll width direction as appropriate).

  As a conventional technique of the meandering control of the metal strip in such a tandem rolling mill, for example, the differential tension of the metal strip on the exit side of each rolling mill of the i-th stand and the (i + 1) th stand of the tandem rolling mill, and each of these rolling mills The amount of shift in the width direction of the metal strip and the crown difference are detected, and the reduction leveling amount of the rolling mill of the i-th stand is controlled based on the detection results (see Patent Document 1). Further, the plate width and meandering amount of the metal strip are measured by an electromagnetic type position detector installed on the exit side of the rolling mill of the i-th stand, and the metal strip is measured by a tension meter installed on the exit side of the rolling mill of the i-th stand. Measuring the total tension and the differential tension, and controlling the rolling leveling amount of the rolling mill of the i-th stand based on these measured values, and the position detection of the electromagnetic type installed on the inlet side of the rolling mill of the first stand There is a meandering control method in which a meandering amount of a metal strip is measured by a device, and a step of controlling the position of an uncoiler based on the measured value is performed (see Patent Document 2). The total tension is the sum (sum tension) of the tension at one end and the tension at the other end in the width direction of the metal strip. On the other hand, the total tension and differential tension of the metal strip on the exit side of each rolling mill in the tandem rolling mill are obtained, and the ratio of the obtained differential tension to the total tension (hereinafter referred to as tension ratio) is within a predetermined target range. There is a meandering control method for controlling the rolling leveling amount of each rolling mill (see Patent Document 3).

JP-A 63-188415 Japanese Patent Laid-Open No. 11-151514 JP 2003-275811 A

  However, in the prior art described in Patent Document 1 described above, when detecting the amount of displacement in the width direction of the metal strip used for controlling the amount of reduction level between the rolling mills or on the outlet side, use of fumes, rolling coolant, etc. Due to the influence of the environment, it is often difficult to detect (measure) this deviation amount. Moreover, in the prior art described in Patent Document 1, the rolling leveling amount of the rolling mill is controlled by an evaluation formula (linear function) based on the differential tension of the metal strip, the amount of deviation in the material width direction, and the crown difference. However, because of the principle of the tension meter that detects the tension of the metal strip, the differential tension of the metal strip and the reduction leveling amount of the rolling mill do not have a linear relationship, so there is a problem in the accuracy of this evaluation formula. That is, it is difficult to control the reduction leveling amount suitable for preventing the meandering of the metal strip in the tandem rolling mill based on the above evaluation formula.

  On the other hand, in the prior art described in Patent Document 2 described above, the metal strip measured in this way can measure the width and meandering amount of the metal strip in the tandem rolling mill without being affected by the use environment such as fume and rolling coolant. The strip leveling amount of the rolling mill and the position of the decoiler are controlled by appropriately using the strip width and meandering amount of the strip and the total tension and differential tension of the metal strip. This control makes it possible to prevent the metal strip from meandering. However, high tension is applied to the metal strip during rolling on the entry side of the tandem rolling mill, and the metal strip is restrained during rolling by the tandem rolling mill. For this reason, when the center of the metal strip is performed by controlling the position of the uncoiler on the entry side of the tandem rolling mill, the metal strip (base material) on the entry side of the tandem rolling mill may be unintentionally deformed. Further, depending on the tension ratio of the metal strip, it may be difficult to prevent the metal strip from meandering in the tandem rolling mill. In this case, due to the meandering of the metal strip in the tandem rolling mill, there is a possibility of causing rolling troubles such as poor biting of the metal strip and drawing fracture.

  Moreover, in the prior art described in Patent Document 3 described above, the rolling leveling amount of each rolling mill is controlled so that the tension ratio of the metal strip on the outlet side of each rolling mill in the tandem rolling mill is within a predetermined target range, By this control, the problems in the prior art described in Patent Document 2 are solved. On the other hand, the target range described above, that is, the range of the tension ratio of the metal strip to prevent the metal strip from meandering in the tandem rolling mill changes with the continuous rolling operation of the metal strip by the tandem rolling mill. There is a case. However, in the prior art described in Patent Document 3, the reduction leveling amount of the rolling mill is controlled so that the tension ratio of the metal strip falls within the target range (a target range suitable for preventing meandering of the metal strip). It is difficult to do. For this reason, a malfunction may occur in the control of the reduction leveling amount for the purpose of preventing meandering of the metal strip. As a result, since the meandering of the metal strip in the tandem rolling mill increases, there is a problem in that rolling trouble such as drawing fracture of the metal strip is caused.

  The present invention has been made in view of the above circumstances, and is capable of stably controlling the meandering of a continuously stripped metal strip and reducing the occurrence of rolling troubles of the metal strip. It is an object to provide a control device and a meandering control method.

  In order to solve the above-mentioned problems and achieve the object, a meandering control device according to the present invention is a meandering control device for controlling meandering of a metal strip in a tandem rolling mill for rolling a metal strip. Tension measuring means for measuring the tension at one end and the other end in the width direction of the metal strip on the exit side of each rolling mill, and the tension at the one end and the other for each exit side of the rolling mill of the tandem rolling mill A tension that is a difference between the tension at the end and a total tension that is the sum of the tension at the one end and the tension at the other end, and a tension that is a ratio of the differential tension to the total tension. The processing means for calculating the ratio and the reduction leveling amount of the next rolling mill arranged in the subsequent stage of the rolling mill to be controlled among the tandem rolling mills, the metal strip of the rolling mill to be controlled Correct the target range of the tension ratio that is the target to prevent the line, so that the tension ratio calculated corresponding to the rolling mill output side of the control target is within the corrected target range, Control means for controlling the reduction leveling amount of the rolling mill to be controlled.

  In the meandering control device according to the present invention, in the above invention, the control means corrects a center value of the target range according to a reduction leveling amount of the next rolling mill, and centers the corrected center value. An upper limit value and a lower limit value of the target range after correction are set.

  Further, the meandering control device according to the present invention is the above invention, wherein the control means includes an influence coefficient indicating an influence of a reduction leveling amount of the next rolling mill on the tension ratio on the outlet side of the controlled rolling mill. The correction value of the target range is calculated by multiplying the rolling leveling amount of the next rolling mill, and the target range is corrected by adding the correction value to the center value, the upper limit value, and the lower limit value of the target range. It is characterized by that.

  Further, the meandering control method according to the present invention is a meandering control method for controlling meandering of the metal strip in a tandem rolling mill for rolling the metal strip, in the width direction of the metal strip on the rolling mill outlet side of the tandem rolling mill. A tension measurement step for measuring each tension at one end and the other end of the tandem rolling machine, and a differential tension that is a difference between the tension at the one end and the tension at the other end Calculating a total tension that is the sum of the tension at the one end and the tension at the other end, and calculating a tension ratio that is a ratio of the differential tension to the total tension; and the tandem rolling A target for preventing meandering of the metal strip in the controlled rolling mill according to the reduction leveling amount of the next rolling mill arranged in the subsequent stage of the controlled rolling mill of the mills A correction step for correcting the target range of the tension ratio, and the control target rolling mill so that the tension ratio calculated corresponding to the controlled rolling mill outlet side is within the corrected target range. And a control step for controlling the amount of reduction leveling.

  Further, in the meandering control method according to the present invention, in the above invention, the correction step corrects a center value of the target range in accordance with a reduction leveling amount of the next rolling mill, and centers the corrected center value. An upper limit value and a lower limit value of the target range after correction are set.

  Further, in the meandering control method according to the present invention, in the above invention, the correction step includes an influence coefficient indicating an influence of a reduction leveling amount of the next rolling mill on the tension ratio on the outlet side of the controlled rolling mill. The correction value of the target range is calculated by multiplying the rolling leveling amount of the next rolling mill, and the target range is corrected by adding the correction value to the center value, the upper limit value, and the lower limit value of the target range. It is characterized by that.

  According to the meandering control device and the meandering control method of the present invention, it is possible to stably control the meandering of the continuously stripped metal strip and reduce the occurrence of rolling troubles of the metal strip. .

FIG. 1 is a diagram illustrating a configuration example of a rolling line to which a meandering control device according to an embodiment of the present invention is applied. FIG. 2 is a diagram illustrating an example of a main configuration of the meandering control device according to the embodiment of the present invention. FIG. 3 is a diagram for explaining the influence of the reduction leveling amount of the next rolling mill on the target range of the steel strip tension ratio on the delivery side of the rolling mill. FIG. 4 is a diagram showing an example of the correlation between the tension ratio of the steel strip on the outlet side of the rolling mill to be controlled and the reduction leveling amount of the next rolling mill. FIG. 5 is a flowchart showing an example of the meandering control method according to the embodiment of the present invention.

  Exemplary embodiments of a meandering control device and a meandering control method according to the present invention will be explained below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiment. Moreover, in each drawing, the same code | symbol is attached | subjected to the same component.

(Rolling line)
First, the configuration of a rolling line to which the meander control of the present invention is applied will be described. FIG. 1 is a diagram illustrating a configuration example of a rolling line to which a meandering control device according to an embodiment of the present invention is applied. In FIG. 1, a part of the rolling line 1, that is, a line portion from the carry-in end of the steel strip 5 to the exit side of the tandem rolling mill 3 is illustrated.

  As shown in FIG. 1, the rolling line 1 in this Embodiment is a line which rolls continuously the steel strip 5 to be processed (for example, cold rolling). In the rolling line 1, an uncoiler 2 for delivering the steel strip 5 and a tandem rolling mill 3 for continuously rolling the delivered steel strip 5 are installed along the conveying path of the steel strip 5. Further, in the vicinity of the tandem rolling mill 3, a meandering control device 10 that controls the meandering of the steel strip 5 in the tandem rolling mill 3 is installed. Although not shown in FIG. 1, the rolling line 1 is arranged at a place where a plurality of transport rolls or the like for sequentially transporting the steel strip 5 in the transport direction (see thick line arrows shown in FIG. 1) is necessary.

  The uncoiler 2 pays out the steel strip 5 from the coil 6 into the rolling line 1 by its rotation. The coil 6 is obtained by winding a steel strip 5 in a coil shape, and is attached to the uncoiler 2 as shown in FIG. The steel strip 5 paid out from the uncoiler 2 is supplied to the tandem rolling mill 3.

  The tandem rolling mill 3 continuously rolls the steel strip 5 that is sequentially transported, and is configured by a plurality of rolling mills that are arranged along the transport path of the steel strip 5. Specifically, when the number of stands of the tandem rolling mill 3 is “n” (n: an integer equal to or greater than 2), as shown in FIG. The rolling mill F1 of the first stand is provided at the side end), and the rolling mill Fn of the nth stand is provided at the most downstream side (the exit end of the tandem rolling mill 3). Although not shown in FIG. 1, a second stand and a second stand are provided between the rolling mill F1 of the first stand of the tandem rolling mill 3 and the rolling mill Fn of the nth stand in the conveying direction of the steel strip 5. The rolling mills of 3 stands,..., N-2 stand and n-1 stand are juxtaposed. The tandem rolling mill 3 continuously rolls the steel strip 5 in the order of the stand numbers of the respective rolling mills by the rolling mills of the first stand to the nth stand. The tandem rolling mill 3 sends the steel strip 5 after the rolling to the delivery side of the tandem rolling mill 3 (the delivery side of the nth stand rolling mill Fn). Thereafter, the steel strip 5 after the completion of rolling is conveyed to the downstream side of the tandem rolling mill 3, subjected to necessary processing by various facilities (not shown) of the rolling line 1, and then wound into a coil shape. .

  The meandering control device 10 controls meandering of the steel strip 5 that is continuously rolled by the tandem rolling mill 3. The meandering control device 10 measures the tension of the steel strip 5 on each outlet side of a plurality of rolling mills (such as the rolling mills F1 and Fn shown in FIG. 1) constituting the tandem rolling mill 3, and based on the measured tension. The leveling level of each of these rolling mills is controlled. The meandering control device 10 controls the meandering of the steel strip 5 in the tandem rolling mill 3 through control of the reduction leveling amounts of the plurality of rolling mills. Thereby, the meandering control device 10 prevents rolling troubles such as drawing fracture of the steel strip 5 in the tandem rolling mill 3.

(Meander control device)
Next, the configuration of the meander control apparatus 10 according to the embodiment of the present invention will be described. FIG. 2 is a diagram illustrating an example of a main configuration of the meandering control device according to the embodiment of the present invention. Hereinafter, the configuration of the meandering control device 10 will be described in detail, focusing on the i-th rolling mill Fi and the (i + 1) -th rolling mill Fi + 1 among the plurality of rolling mills constituting the tandem rolling mill 3 described above. . In the present embodiment, the rolling mill Fi of the i-th stand is a controlled rolling mill of the tandem rolling mill 3. The i + 1 stand rolling mill Fi + 1 is the next rolling mill arranged in the subsequent stage of the rolling mill Fi to be controlled among the tandem rolling mills 3. “I” and “i + 1” are integers satisfying 1 ≦ i <i + 1 ≦ n.

  As shown in FIG. 2, the meandering control device 10 includes tension meters 11 a, 11 b, 12 a, 12 b that measure the tension of the steel strip 5 on each outlet side of the rolling mill Fi, Fi + 1, and an arithmetic process for each measured tension. Tension calculating units 13 and 14, leveling devices 15a, 15b, 16a and 16b for adjusting the respective leveling levels of the rolling mills Fi and Fi + 1, and a control unit 17 for controlling the respective leveling levels of the rolling mills Fi and Fi + 1. With.

  The tensiometers 11a, 11b, 12a, and 12b function as tension measuring means for measuring the tensions at one end and the other end in the width direction of the steel strip 5 on each outlet side of the rolling mills Fi and Fi + 1. Specifically, each of the tensiometers 11a, 11b, 12a, and 12b is realized by using a load cell or the like, measures (detects) the vertical load of the steel strip 5, and fixes the obtained vertical load and the steel strip 5 to each other. The tension of the steel strip 5 is measured based on the contact angle.

As shown in FIG. 2, the tension meters 11 a and 11 b are arranged on the exit side of the rolling mill Fi of the i-th stand. Specifically, the tensiometer 11a is disposed on the exit side of the rolling mill Fi and on the side where the operator is located on both sides in the width direction of the steel strip 5 (hereinafter referred to as the work side). The tension meter 11a measures the tension (hereinafter referred to as work-side tension) T _i ws at one end of the steel strip 5 in the width direction, specifically, the end on the work side, on the exit side of the rolling mill Fi. . On the other hand, the tensiometer 11b is arranged on the exit side of the rolling mill Fi and on the side where the drive device is located on both sides in the width direction of the steel strip 5 (hereinafter referred to as drive side). The tensiometer 11b measures the tension (hereinafter referred to as drive-side tension) T _i ds at the other end of the steel strip 5 in the width direction, specifically, the end on the drive side, on the exit side of the rolling mill Fi. To do. The tensiometers 11a and 11b respectively measure the working side tension T _i ws and the driving side tension T _i ds of the steel strip 5 sequentially rolled by the rolling mill Fi, and each time the working side tension T _i ws and the driving side tension are measured. Each measured value of T _i ds is transmitted to the tension calculator 13.

As shown in FIG. 2, the tensiometers 12 a and 12 b are arranged on the exit side of the rolling mill Fi + 1 of the (i + 1) th stand. Specifically, the tensiometer 12a is disposed on the working side of both sides in the width direction of the steel strip 5 on the exit side of the rolling mill Fi + 1. The tension meter 12a measures the work side tension T _{i + 1} ws of the steel strip 5 on the exit side of the rolling mill Fi + 1. On the other hand, the tensiometer 12b is arranged on the drive side of the both sides in the width direction of the steel strip 5 on the exit side of the rolling mill Fi + 1. The tension meter 12b measures the drive side tension T _{i + 1} ds of the steel strip 5 on the exit side of the rolling mill Fi + 1. The tensiometers 12a and 12b respectively measure the working side tension T _{i + 1} ws and the driving side tension T _{i + 1} ds of the steel strip 5 that is sequentially rolled by the rolling mill Fi + 1, and each time the working side tension T _{i + is} measured. Each measured value of ₁ ws and drive side tension T _{i + 1} ds is transmitted to the tension calculator 14.

The tension calculation units 13 and 14 function as calculation processing means for performing calculation processing based on the measured tension value of the steel strip 5 for each exit side of the rolling mills Fi and Fi + 1. Specifically, as shown in FIG. 2, the tension calculation unit 13 is connected to the tension meters 11a and 11b on the exit side of the rolling mill Fi, and the working-side tension of the steel strip 5 measured by the tension meters 11a and 11b. T _i ws and drive side tension T _i ds are obtained. In each case, the tension calculation unit 13 calculates the differential tension ΔT _i which is the difference between the work side tension T _i ws and the drive side tension T _i ds of the steel strip 5, and the work side tension T _i ws and the drive side tension T _i. to calculate the total tension T _i, which is the sum of the ds. Further, the tension calculator 13 calculates a tension ratio (ΔT _i / T _i ) that is a ratio of the calculated differential tension ΔT _{i to} the total tension T _i . The tension calculation unit 13 transmits the calculated tension ratio (ΔT _i / T _i ) to the control unit 17 each time such tension calculation processing is executed. On the other hand, as shown in FIG. 2, the tension calculator 14 is connected to the tension meters 12a and 12b on the exit side of the rolling mill Fi + 1, and the work side tension T _{i + of} the steel strip 5 measured by the tension meters 12a and 12b. ₁ ws and drive side tension T _{i + 1} ds are acquired. In each case, the tension calculation unit 14 calculates a differential tension ΔT _{i + 1} , which is a difference between the working side tension T _{i + 1} ws and the driving side tension T _{i + 1} ds of the steel strip 5, and these working side tensions T _{i +. A} total tension T _{i + 1} which is the sum of ₁ ws and drive side tension T _{i + 1} ds is calculated. Further, the tension calculator 14 calculates a tension ratio (ΔT _{i + 1} / T _{i + 1} ) that is a ratio of the calculated differential tension ΔT _{i + 1 to} the total tension T _{i + 1} . The tension calculation unit 14 transmits the calculated tension ratio (ΔT _{i + 1} / T _{i + 1} ) to the control unit 17 each time such tension calculation processing is executed.

The leveling devices 15a, 15b, 16a, and 16b are for adjusting the reduction leveling amount of the rolling mills Fi and Fi + 1. As shown in FIG. 2, the leveling devices 15a and 15b are arranged in a rolling mill Fi of the i-th stand. Specifically, the leveling device 15a is disposed on the working side of both sides of the rolling mill Fi in the roll width direction. Based on the control of the control unit 17, the leveling device 15a has a leveling amount (hereinafter referred to as a work-side leveling amount) ΔS at the work side end in the roll width direction of the pair of work rolls 3a and 3b provided in the rolling mill Fi. _i Adjust ws. On the other hand, the leveling device 15b is disposed on the drive side of both sides in the roll width direction of the rolling mill Fi. Based on the control of the control unit 17, the leveling device 15b adjusts a leveling amount ΔS _i ds at the driving side end in the roll width direction of the work rolls 3a and 3b of the rolling mill Fi (hereinafter referred to as driving side leveling amount). . The leveling devices 15a and 15b adjust the reduction leveling amount ΔS _i of the rolling mill Fi by adjusting the work side leveling amount ΔS _i ws and the driving side leveling amount ΔS _i ds of the work rolls 3a and 3b.

In the rolling mill Fi of the i-th stand, the work-side leveling amount ΔS _i ws is determined by the work-side end portions of the work rolls 3a and 3b that sandwich (bite) the steel strip 5 from both the front and back surfaces when the steel strip 5 is rolled. It is a roll gap. The driving side leveling amount ΔS _i ds is a roll gap at the driving side end of the work rolls 3a and 3b. The reduction leveling amount ΔS _i is a roll gap between the work rolls 3a and 3b, and is expressed by a difference between the above-described work-side leveling amount ΔS _i ws and the drive-side leveling amount ΔS _i ds.

As shown in FIG. 2, the leveling devices 16a and 16b are arranged in a rolling mill Fi + 1 of the (i + 1) th stand. Specifically, the leveling device 16a is arranged on the working side of both sides in the roll width direction of the rolling mill Fi + 1. The leveling device 16a adjusts the work-side leveling amount ΔS _{i + 1} ws of the pair of work rolls 3c and 3d provided in the rolling mill Fi + 1 based on the control of the control unit 17. On the other hand, the leveling device 16b is disposed on the drive side of both sides in the roll width direction of the rolling mill Fi + 1. The leveling device 16b adjusts the drive-side leveling amount ΔS _{i + 1} ds of the work rolls 3c and 3d in the rolling mill Fi + 1 based on the control of the control unit 17. The leveling devices 16a and 16b adjust the work-side leveling amount ΔS _{i + 1} ws and the drive-side leveling amount ΔS _{i + 1} ds of the work rolls 3c and 3d, thereby reducing the rolling leveling amount ΔS _{i + 1} of the rolling mill Fi + 1. adjust.

In the rolling mill Fi + 1 of the (i + 1) th stand, the work side leveling amount ΔS _{i + 1} ws is the work side end of the work rolls 3c, 3d that sandwiches (bits into) the steel strip 5 from both the front and back surfaces when the steel strip 5 is rolled. Part roll gap. The driving side leveling amount ΔS _{i + 1} ds is a roll gap at the driving side end of the work rolls 3c and 3d. The reduction leveling amount ΔS _{i + 1} is the roll gap between the work rolls 3c and 3d, and is expressed by the difference between the above-described work-side leveling amount ΔS _{i + 1} ws and the drive-side leveling amount ΔS _{i + 1} ds. .

The control unit 17 controls the reduction leveling amount of each of the plurality of rolling mills F1 to Fn constituting the tandem rolling mill 3 shown in FIG. 1, and through the control of the reduction leveling amounts of these rolling mills F1 to Fn, the tandem The meandering of the steel strip 5 in the rolling mill 3 is controlled. Specifically, as shown in FIG. 2, the control unit 17 is connected to the tension calculation units 13 and 14, and acquires the tension ratio (ΔT _i / T _i ) on the exit side of the rolling mill Fi from the tension calculation unit 13. Then, the tension ratio (ΔT _{i + 1} / T _{i + 1} ) on the exit side of the rolling mill Fi + 1 is acquired from the tension calculator 14. The control unit 17 acquires the reduction leveling amount ΔS _{i + 1} of the rolling mill Fi + 1 based on the tension ratio (ΔT _{i + 1} / T _{i + 1} ) or the like. Here, the rolling mill Fi is a controlled rolling mill of the tandem rolling mill 3. The rolling mill Fi + 1 is a next rolling mill arranged in the subsequent stage of the rolling mill Fi to be controlled among the tandem rolling mills 3. The control unit 17 corrects the target range of the tension ratio (ΔT _i / T _i ) in the rolling mill Fi to be controlled according to the rolling leveling amount ΔS _{i + 1} of the rolling mill Fi + 1. The target range is a range of tension ratio to target in order to prevent the meandering of the steel strip 5 in the rolling mill Fi of the control object (ΔT _i / T _i). Hereinafter, the target range means the target range of the tension ratio of the metal strip for the purpose of preventing meandering of the metal strip (steel strip 5 in the present embodiment) in the tandem rolling mill 3. The control unit 17 controls the control target so that the tension ratio (ΔT _i / T _i ) calculated by the tension calculation unit 13 corresponding to the exit side of the rolling mill Fi to be controlled is within the corrected target range. The rolling leveling amount ΔS _i of the rolling mill Fi is controlled. The control unit 17 controls the meandering of the steel strip 5 in the rolling mill Fi through such control of the reduction leveling amount ΔS _i . The control unit 17 performs the same control as the control of the reduction leveling amount ΔS _i for the rolling mill Fi described above on each rolling mill of the tandem rolling mill 3. Thereby, the control part 17 controls meandering of the steel strip 5 in each rolling mill of the tandem rolling mill 3.

Here, the reduction leveling amount ΔS _{i + 1} of the rolling mill Fi + 1 used for the correction processing of the target range of the tension ratio (ΔT _i / T _i ) described above is the tension ratio (ΔT _i + 1) on the outlet side of the rolling mill Fi _{+ 1.} / T _{i + 1} ) is controlled so as to be within the corrected target range. That is, the control unit 17 sets the target range of the tension ratio (ΔT _{i + 1} / T _{i + 1} ) in the rolling mill Fi + 1 according to the reduction leveling amount of the rolling mill of the i + 2 stand arranged in the subsequent stage of the rolling mill Fi + 1. Correct. The controller 17 has the tension ratio (ΔT _{i + 1} / T _{i + 1} ) calculated by the tension calculator 14 corresponding to the exit side of the rolling mill Fi + 1 within the corrected target range in the rolling mill Fi + 1. Thus, the reduction leveling amount ΔS _{i + 1} of the rolling mill Fi _{+ 1} is controlled. On the other hand, when the rolling mill Fi + 1 is the final stand of the tandem rolling mill 3, that is, the rolling mill Fn of the nth stand, the rolling mill of the tandem rolling mill 3 is not arranged in parallel to the subsequent stage of the rolling mill Fi + 1. In this case, the control unit 17 sets the tension ratio (ΔT _{i + 1} / T _{i + 1} ) calculated by the tension calculation unit 14 corresponding to the exit side of the rolling mill Fi + 1 to the rolling mill Fi + 1 (that is, the rolling mill Fn). On the other hand, the reduction leveling amount ΔS _{i + 1} of the rolling mill Fi _{+ 1} is controlled so as to be within a preset target range.

  The meandering control device 10 applied to the tandem rolling mill 5 shown in FIG. 1 includes a plurality of rolling mills constituting the tandem rolling mill 3 as exemplified by the tension meters 11a, 11b, 12a, and 12b shown in FIG. A plurality of work-side tension meters and drive-side tension meters are provided corresponding to F1 to Fn. The plurality of work-side tension meters and drive-side tension meters constitute tension measuring means for measuring the work-side tension and the drive-side tension of the steel strip 5 on the rolling mill output side of the tandem rolling mill 3. The plurality of work-side tension meters and the drive-side tension meters are provided to appropriately maintain the tension of the steel strip 5 between the rolling mills of the tandem rolling mill 3, but in the present invention, It is also used for meandering control of the steel strip 5.

  The meandering control device 10 includes a plurality of tension calculation units corresponding to the plurality of rolling mills F1 to Fn, as exemplified by the tension calculation units 13 and 14 shown in FIG. The plurality of tension calculation units calculate the differential tension and the total tension between the working side tension and the driving side tension of the steel strip 5 for each rolling mill exit side of the tandem rolling mill 3, and all the calculated differential tensions are calculated. An arithmetic processing means for calculating a tension ratio with respect to the tension is configured. Further, the meandering control device 10 includes a plurality of work-side leveling devices and drive-side leveling devices corresponding to the plurality of rolling mills F1 to Fn, as exemplified by the leveling devices 15a, 15b, 16a, and 16b shown in FIG. Is provided. The plurality of work side leveling devices and drive side leveling devices constitute leveling adjusting means for adjusting the reduction leveling amount of each rolling mill of the tandem rolling mill 3.

  In the meandering control apparatus 10 having the configuration as described above, the control unit 17 is connected to each of a plurality of tension calculation units arranged corresponding to the plurality of rolling mills F1 to Fn, and from the plurality of tension calculation units. The tension ratio of the steel strip 5 on each outlet side of the rolling mills F1 to Fn is acquired. Based on the acquired tension ratios, the control unit 17 performs centralized control of the rolling leveling amounts of the rolling mills F1 to Fn, as exemplified by the control for the rolling mill Fi described above. The meandering control device 10 includes a plurality of control units 17 corresponding to the plurality of rolling mills F1 to Fn, and the plurality of control units 17 may perform distributed control of the reduction leveling amounts of the rolling mills F1 to Fn. Good.

(Target range of tension ratio)
Next, the target range of the tension ratio on the rolling mill exit side of the steel strip 5 used for the meandering control of the steel strip 5 according to the present invention will be described. In the present invention, the meandering control of the steel strip 5 in the tandem rolling mill 3 is performed by controlling the rolling leveling amounts of the rolling mills F1 to Fn constituting the tandem rolling mill 3. Specifically, when meandering to the work side occurs in the steel strip 5 in the rolling mill Fi of the i-th stand of the tandem rolling mill 3, the work rolls of the work rolls 3a and 3b (see FIG. 2) of the rolling mill Fi. The reduction leveling amount ΔS _i is controlled so as to tighten the gap. Thereby, meandering of the steel strip 5 to this working side is suppressed. On the other hand, when meandering to the drive side occurs in the steel strip 5 in the rolling mill Fi, the reduction leveling amount ΔS _i is controlled so as to tighten the drive side roll gap of the work rolls 3a and 3b of the rolling mill Fi. Thereby, the meandering of the steel strip 5 to this drive side is suppressed. In such meandering control of the steel strip 5, the tension ratio (ΔT _i / T _i ) of the steel strip 5 on the exit side of the rolling mill Fi changes in accordance with the reduction leveling amount ΔS _i . That is, when the work side roll gap of the rolling mill Fi is tightened, the elongation of the work side portion of the steel strip 5 sent to the exit side of the rolling mill Fi is increased, and accordingly, the exit side of the rolling mill Fi. The working side tension T _i ws of the steel strip 5 decreases. On the other hand, when the drive side roll gap of the rolling mill Fi is tightened, the elongation of the drive side portion of the steel strip 5 sent to the exit side of the rolling mill Fi increases, and accordingly, the exit side of the rolling mill Fi. The drive-side tension T _i ds of the steel strip 5 at is reduced. Based on the change of the working side tension T _i ws or the driving side tension T _i ds, the tension ratio (ΔT _i / T _i ) of the steel strip 5 changes.

As described above, the tension ratio (ΔT _i / T _i ) of the steel strip 5 that changes in accordance with the reduction leveling amount ΔS _i is obtained by investigating the occurrence of drawing fracture in the past rolling results. It became clear that there was a range where breakage could be prevented. In the present invention, the range of the tension ratio (ΔT _i / T _i ) capable of preventing the drawing fracture is set to the target of the tension ratio (ΔT _i / T _i ) for preventing the steel strip 5 from meandering in the rolling mill Fi. The range is Rt. By controlling the rolling leveling amount ΔS _i of the rolling mill Fi so that the tension ratio (ΔT _i / T _i ) is within the target range Rt, rolling troubles such as drawing fracture due to meandering of the steel strip 5 can be prevented. can do. In addition, as this target range Rt, the range of -0.2 or more and 0.2 or less is mentioned, for example as disclosed by Unexamined-Japanese-Patent No. 2003-275811. Such a target range Rt can be appropriately set and changed in consideration of properties such as the material, material width, material thickness, and unit tension of the steel strip 5.

On the other hand, in the actual operation of the tandem rolling mill 3, the center value Rc of the target range Rt described above changes as the rolling continues, and as the center value Rc changes, the upper limit Ra and the lower limit of the target range Rt. The value Rb changes. Therefore, if the reduction leveling amount ΔS _i is controlled while continuing the operation of the tandem rolling mill 3 without considering the change of the target range Rt, a malfunction occurs in the control of the reduction leveling amount ΔS _i , and the steel strip 5 is meandered. As a result, it became clear that drawing fracture of the steel strip 5 occurred.

The inventors of the present invention have intensively investigated the relationship between each control factor of rolling by the tandem rolling mill 3 and the target range Rt of the tension ratio (ΔT _i / T _i ). As a result, the reduction leveling amount ΔS _{i + 1} of the rolling mill Fi + 1 of the (i + 1) th stand arranged in the subsequent stage of the rolling mill Fi of the i-th stand affects the tension ratio (ΔT _i / T _i ) on the outlet side of the rolling mill Fi. Was found to affect. FIG. 3 is a diagram for explaining the influence of the reduction leveling amount of the next rolling mill on the target range of the steel strip tension ratio on the delivery side of the rolling mill. FIG. 3 shows the change over time of the target range Rt of the tension ratio (ΔT _i / T _i ) accompanying the change over time of the reduction leveling amount ΔS _{i + 1} .

As shown in FIG. 3, the target range Rt of the tension ratio (ΔT _i / T _i ) changes corresponding to the change in the reduction leveling amount ΔS _{i + 1} (see the correlation line L1). Specifically, the center value Rc of the target range Rt is reduction leveling amount [Delta] S i _{+ 1} is constant period is constant, reduction leveling amount [Delta] S i _{+ period 1} is changed increases, has risen changed. Similar to the change in the center value Rc, the upper limit Ra and the lower limit Rb of the target range Rt are changed. Therefore, without causing a malfunction in the control of reduction leveling amount [Delta] S _i, to control stably the meandering of the steel strip 5 in the rolling mill Fi in accordance with the rolling mill Fi + 1 of reduction leveling amount [Delta] S i _{+ 1,} It is necessary to correct the target range Rt of the tension ratio (ΔT _i / T _i ) in the rolling mill Fi.

In the present invention, the correction of the target range Rt described above is performed by setting the influence coefficient α indicating the influence of the rolling leveling amount ΔS _{i + 1} of the rolling mill Fi _{+ 1} on the tension ratio (ΔT _i / T _i ) on the outlet side of the rolling mill Fi. Take it into consideration. Specifically, the control unit 17 (see FIG. 2) of the meandering control apparatus 10 according to the present embodiment multiplies the influence coefficient α and the reduction leveling amount ΔS _{i + 1} as shown in the following equation (1). A correction value H for the target range Rt is calculated. The controller 17 adds the correction value H to the center value Rc, the upper limit value Ra, and the lower limit value Rb of the target range Rt, thereby correcting the target range Rt. The control unit 17 prevents the malfunction of this control with high accuracy by controlling the reduction leveling amount ΔS _i of the rolling mill Fi so that the tension ratio (ΔT _i / T _i ) is within the corrected target range Rt. In addition, the meandering of the steel strip 5 in the rolling mill Fi can be stably controlled.

Correction value H = influence coefficient α × reduction leveling amount ΔS _{i + 1 of the} next rolling mill (1)

The influence coefficient α described above is determined by using the tandem rolling mill 3 and controlling the reduction leveling amount ΔS _{i + 1} with respect to the rolling mill Fi + 1 of the ( _{i + 1} ) th stand to the tension ratio of the steel strip 5 on the exit side of the rolling mill Fi of the ith stand ( It can be calculated by quantitatively evaluating the influence on ΔT _i / T _i ). FIG. 4 is a diagram showing an example of the correlation between the tension ratio of the steel strip on the outlet side of the rolling mill to be controlled and the reduction leveling amount of the next rolling mill. In the above evaluation, the rolling mill Fi + 1 with reduction leveling amount [Delta] S i _{+ 1,} the actual data for the reduction leveling amount [Delta] S i _{+ 1} tension ratio obtained corresponding to the control of the (ΔT _i / T _i) The regression analysis was performed using. As a result, as shown in FIG. 4, it was found that a linear correlation is established between the reduction leveling amount ΔS _{i + 1} and the tension ratio (ΔT _i / T _i ). For example, when the reduction leveling amount ΔS _{i + 1} is taken on the x-axis of the orthogonal biaxial coordinate system and the tension ratio (ΔT _i / T _i ) is taken on the y-axis, the reduction leveling amount ΔS _{i + 1} and the tension ratio (ΔT The correlation line L2 with _i / T _i ) can be expressed by the following equation (2). The coefficient of determination R ² when the regression analysis was performed to derive the formula (2) was “0.9858”.

y = 0.0047x−2.1522 (2)

Based on this equation (2), 4.4 [%] / 1000 [μm] was calculated as an example of the influence coefficient α. In the above regression analysis, the reduction leveling amount ΔS _{i + 1} is obtained by subtracting the driving side leveling amount ΔS _{i + 1} ds from the work side leveling amount ΔS _{i + 1} ws of the rolling mill Fi + 1 (= ΔS _{i + 1).} ws−ΔS _{i + 1} ds). The differential tension ΔT _i was obtained by subtracting the drive side tension T _i ds from the work side tension T _i ws of the steel strip 5 on the exit side of the rolling mill Fi (= T _i ws−T _i ds).

(Meander control method)
Next, the meander control method according to the embodiment of the present invention will be described. FIG. 5 is a flowchart showing an example of the meandering control method according to the embodiment of the present invention. In the meandering control method according to the present embodiment, the meandering control device 10 (see FIGS. 1 and 2) executes each processing step of steps S101 to S104 shown in FIG. 5 to continuously roll the steel strip 5. The meandering of the steel strip 5 in the tandem rolling mill 3 is controlled.

That is, as shown in FIG. 5, the meandering control device 10 measures the tension of the steel strip 5 on the exit side of each rolling mill of the tandem rolling mill 3 (Step S <b> 101). In step S101, the tensiometers 11a and 11b measure the work side tension T _i ws and the drive side tension T _i ds of the steel strip 5 on the exit side of the rolling mill Fi of the i-th stand, respectively. The tension meters 11 a and 11 b transmit the measured work-side tension T _i ws and drive-side tension T _i ds to the tension calculator 13. In parallel with this, the tensiometers 12a and 12b respectively measure the work side tension T _{i + 1} ws and the drive side tension T _{i + 1} ds of the steel strip 5 on the exit side of the rolling mill Fi + 1 of the (i + 1) th stand. The tension meters 12 a and 12 b transmit the measured work side tension T _{i + 1} ws and drive side tension T _{i + 1} ds to the tension calculation unit 14.

Next, the meandering control apparatus 10 performs the calculation process of the tension of the steel strip 5 measured in step S101 for each rolling mill exit side of the tandem rolling mill 3 (step S102). In step S102, the tension calculating unit 13 acquires the work side tension T _i ws and the drive side tension T _i ds from the tension meters 11a and 11b on the exit side of the rolling mill Fi. Next, the tension calculation unit 13 subtracts the drive side tension T _i ds from the work side tension T _i ws by subtracting the differential tension ΔT _i between the work side tension T _i ws and the drive side tension T _i ds, for example. calculate. Further, the tension calculation unit 13 calculates the total tension T _i by adding the work side tension T _i ws and the drive side tension T _i ds. Subsequently, the tension calculator 13 calculates a tension ratio (ΔT _i / T _i ) that is a ratio of the differential tension ΔT _i calculated as described above to the total tension T _i . The tension calculation unit 13 transmits the obtained tension ratio (ΔT _i / T _i ) to the control unit 17. In parallel with this, the tension calculation unit 14 acquires the work-side tension T _{i + 1} ws and the drive-side tension T _{i + 1} ds from the tension meters 12a and 12b on the exit side of the rolling mill Fi + 1. The tension calculation unit 14 performs the same calculation process as the above-described tension calculation unit 13 to calculate the differential tension ΔT _{i + 1} and the total tension T _{i + 1} , and the tension ratio (ΔT _{i + 1} / T _{i + 1} ) Calculate. The tension calculation unit 14 transmits the obtained tension ratio (ΔT _{i + 1} / T _{i + 1} ) to the control unit 17.

Subsequently, the meandering control device 10 sets the target of the tension ratio (ΔT _i / T _i ) of the steel strip 5 in the rolling mill Fi according to the reduction leveling amount of the next rolling mill arranged in the subsequent stage of the rolling mill Fi to be controlled. The range Rt is corrected (step S103). In step S <b> 103, the control unit 17 acquires the tension ratio (ΔT _i / T _i ) on the exit side of the rolling mill Fi of the i-th stand that is the control target of the tandem rolling mill 3 from the tension calculation unit 13. Subsequently, the control unit 17 determines the tension ratio (ΔT _i) in the rolling mill Fi according to the reduction leveling amount ΔS _{i + 1} of the rolling mill Fi + 1 that is the next rolling mill arranged in the subsequent stage of the rolling mill Fi to be controlled. / T _i ) target range Rt is corrected. As described above, the target range Rt is a target tension ratio (ΔT _i / T _i ) range for preventing the steel strip 5 from meandering in the rolling mill Fi to be controlled. Such a target range Rt is initially set in the control unit 17 in advance for each rolling mill of the tandem rolling mill 3, for example.

Here, the reduction leveling amount ΔS _{i + 1} was controlled such that the tension ratio (ΔT _{i + 1} / T _{i + 1} ) on the exit side of the rolling mill Fi + 1 was within the corrected target range of the rolling mill Fi + 1. Is. The controller 17 acquires the tension ratio (ΔT _{i + 1} / T _{i + 1} ) from the tension calculator 14. The controller 17 calculates the reduction leveling amount ΔS _{i + 1} so that the acquired tension ratio (ΔT _{i + 1} / T _{i + 1} ) is within the corrected target range in the rolling mill Fi + 1. The control unit 17 corrects the center value Rc of the target range Rt according to the reduction leveling amount ΔS _{i + 1} , and corrects the upper limit Ra and the lower limit of the target range Rt after correction with the corrected center value Rc as the center. Rb is set. Specifically, the control unit 17 calculates the correction value H by multiplying the influence coefficient α and the reduction leveling amount ΔS _{i + 1} based on the above-described equation (1). As described above, the influence coefficient α is a coefficient indicating the influence of the reduction leveling amount ΔS _{i + 1} of the next rolling mill on the tension ratio (ΔT _i / T _i ) on the outlet side of the rolling mill Fi to be controlled. . The control unit 17 adds the correction value H calculated in this way to the center value Rc, the upper limit value Ra, and the lower limit value Rb of the target range Rt. Accordingly, the control unit 17 corrects the center value Rc, the upper limit value Ra, and the lower limit value Rb of the target range Rt to values that take into account the reduction leveling amount ΔS _{i + 1} . The control unit 17 sets the range of the tension ratio (ΔT _i / T _i ) determined by the center value Rc, the upper limit value Ra, and the lower limit value Rb corrected in this way, after correction according to the reduction leveling amount ΔS _{i + 1} . Set as the target range Rt.

After executing step S103, the meandering control device 10 determines that the tension ratio (ΔT _i / T _i ) of the steel strip 5 calculated corresponding to the exit side of the rolling mill Fi to be controlled is the target range after the correction in step S103. The rolling leveling amount ΔS _i of the rolling mill Fi is controlled so as to be within Rt (step S104). In step S104, the control unit 17 sets the work-side leveling amount ΔS _i ws and the drive side so that the tension ratio (ΔT _i / T _i ) calculated by the tension calculation unit 13 falls within the corrected target range Rt. A leveling amount ΔS _i ds is calculated. Based on the calculated work-side leveling amount ΔS _i ws and drive-side leveling amount ΔS _i ds, the control unit 17 controls the adjustment of the reduction leveling amount ΔS _i by the leveling devices 15a and 15b, and this reduction leveling amount ΔS _i. Through this control, the meandering of the steel strip 5 in the rolling mill Fi is controlled.

Specifically, when the calculated tension ratio (ΔT _i / T _i ) exceeds the upper limit value Ra of the corrected target range Rt, the control unit 17 tightens the work side as the work side leveling amount ΔS _i ws. The quantity G _i ws is calculated. Further, the control unit 17 calculates a drive side tightening amount G _i ds (for example, G _i ds = 0) smaller than the work side tightening amount G _i ws as the drive side leveling amount ΔS _i ds. The control unit 17 transmits the work-side leveling amount ΔS _i ws (= G _i ws) and the drive-side leveling amount ΔS _i ds (= G _i ds <G _i ws) thus calculated to the leveling devices 15a and 15b, respectively. To do. The control unit 17 controls the leveling device 15a to adjust the roll gap of the transmitted work side tightening amount G _i ws and adjusts the roll gap of the transmitted drive side tightening amount G _i ds. The leveling device 15b is controlled. Thus, the control unit 17 controls the reduction leveling amount ΔS _i of the rolling mill Fi when the tension ratio (ΔT _i / T _i ) exceeds the corrected upper limit value Ra, and controls the reduction leveling amount ΔS _i . Through, the meandering of the steel strip 5 in the rolling mill Fi is controlled.

On the other hand, when the calculated tension ratio (ΔT _i / T _i ) is not more than the upper limit value Ra of the corrected target range Rt and not less than the lower limit value Rb, the control unit 17 sets the work side leveling amount ΔS _i ws. The work side tightening amount G _i ws (= 0) is calculated, and the driving side tightening amount G _i ds (= 0) is calculated as the driving side leveling amount ΔS _i ds. The control unit 17 transmits the work-side leveling amount ΔS _i ws (= 0) and the drive-side leveling amount ΔS _i ds (= 0) thus calculated to the leveling devices 15a and 15b, respectively. The control unit 17 performs control based on the transmitted work-side tightening amount G _i ws on the leveling device 15a, and performs control based on the transmitted drive-side tightening amount G _i ds on the leveling device 15b. Do. That is, when the tension ratio (ΔT _i / T _i ) described above is within the corrected target range Rt, the control unit 17 does not change the roll gap on both the working side and the driving side (does not change the reduction position). The leveling devices 15a and 15b are controlled. Accordingly, the control unit 17 controls the reduction leveling amount ΔS _i of the rolling mill Fi when the tension ratio (ΔT _i / T _i ) is within the corrected target range Rt, and the control of the reduction leveling amount ΔS _i is performed. Through, the meandering of the steel strip 5 in the rolling mill Fi is controlled.

On the other hand, when the tension ratio (ΔT _i / T _i ) described above is less than the lower limit value Rb of the corrected target range Rt, the control unit 17 uses the drive side tightening amount G _i as the work side leveling amount ΔS _i ws. A work-side tightening amount G _i ws (for example, G _i ws = 0) smaller than ds is calculated. Further, the control unit 17 calculates a drive side tightening amount G _i ds (> G _i ws) as the drive side leveling amount ΔS _i ds. The control unit 17 transmits the work side leveling amount ΔS _i ws (= G _i ws <G _i ds) and the drive side leveling amount ΔS _i ds (= G _i ds) thus calculated to the leveling devices 15a and 15b, respectively. To do. The control unit 17 controls the leveling device 15a to adjust the roll gap of the transmitted work side tightening amount G _i ws and adjusts the roll gap of the transmitted drive side tightening amount G _i ds. The leveling device 15b is controlled. Accordingly, the control unit 17 controls the reduction leveling amount ΔS _i of the rolling mill Fi when the tension ratio (ΔT _i / T _i ) is less than the corrected lower limit value Rb, and controls the reduction leveling amount ΔS _i . Through, the meandering of the steel strip 5 in the rolling mill Fi is controlled.

  The control part 17 performs each processing step of step S101-S104 mentioned above with respect to each rolling mill F1-Fn of the tandem rolling mill 3, respectively. After executing Step S104, the control unit 17 returns to Step S101 and repeats the processing steps after Step S101 as appropriate.

On the other hand, the control unit 17 performs meandering control of the steel strip 5 as described below with respect to the n-th rolling mill Fn of the tandem rolling mill 3. That is, the control unit 17 acquires the tension ratio of the steel strip 5 on the exit side of the rolling mill Fn from a tension calculation unit (not shown) disposed on the exit side of the rolling mill Fn. Next, the control unit 17 corrects the target range of the tension ratio of the steel strip 5 in the rolling mill Fn. In this target range correction process, since the rolling mill of the tandem rolling mill 3 is not provided in parallel to the subsequent stage of the rolling mill Fn, the parameter “the rolling reduction leveling amount ΔS _{i + 1 of the} next rolling mill” described above is used. "Is" 0 ". Therefore, the control unit 17 calculates “0” as the correction value H of the target range of the tension ratio in the rolling mill Fn. The control unit 17 corrects the target range based on the correction value H (= 0). That is, the target range of the tension ratio in the rolling mill Fn does not change before and after the correction, and is the same as the range that is preset in advance based on, for example, the properties of the steel strip 5, the rolling schedule, and the like. In the present invention, the target range including the correction value H (= 0) is set as a target range after correction by the correction value H. The control unit 17 controls the reduction leveling amount of the rolling mill Fn so that the tension ratio of the steel strip 5 on the exit side of the rolling mill Fn is within the corrected target range in the rolling mill Fn. Thereby, the control part 17 controls the meandering of the steel strip 5 in the rolling mill Fn.

  In addition, the meandering control apparatus 10 concerning this Embodiment repeatedly performs the process step of step S101-S104 mentioned above suitably, and, thereby, rolls the tension ratio of the steel strip 5 in each delivery side of the rolling mills F1-Fn. The rolling leveling amounts of the rolling mills F1 to Fn are controlled so as to be within the target range for each mill. As a result, the meandering control device 10 can stably suppress the meandering of the steel strip 5 in the tandem rolling mill 3 and reliably prevent rolling troubles such as drawing fracture of the steel strip 5. For this reason, the meandering correction amount of the steel strip 5 by the operation of the meandering correction roll (not shown) or the uncoiler 2 (see FIG. 1) arranged on the entry side of the tandem rolling mill 3 can be limited. For this reason, unintended deformation does not occur in the steel strip 5 as the base material on the entry side of the tandem rolling mill 3. However, the meandering correction of the steel strip 5 by the operation of the meandering correction roll or the uncoiler 2 arranged on the entry side of the tandem rolling mill 3 is possible within a range where the unintentional deformation of the steel strip 5 as the base material does not occur.

  As described above, in the embodiment of the present invention, the tension ratio of the differential tension with respect to the sum (total tension) of the working side tension and the driving side tension of the steel strip is determined for each rolling mill exit side of the tandem rolling mill. Calculate and correct the target range of the tension ratio to prevent meandering of the steel strip in the controlled rolling mill according to the rolling leveling amount of the next rolling mill arranged in the latter stage of the controlled rolling mill among the tandem rolling mills Then, the reduction leveling amount of the rolling mill to be controlled is controlled so that the tension ratio is within the corrected target range. For this reason, even if the target range of the tension ratio changes with the continuous rolling operation of the steel strip by the tandem rolling mill, the tension ratio of the steel strip on the rolling mill exit side is within the target range. In addition, the reduction leveling amount of each rolling mill can be reliably controlled. As a result, the control of the leveling level suitable for preventing the meandering of the steel strip can be performed on each rolling mill of the tandem rolling mill without causing the malfunction, and therefore, the cause of the malfunction of the meander control is eliminated. The steel strip meandering control can be executed for each rolling mill of the tandem rolling mill. As a result, it is possible to stably control the meandering of the steel strip that is continuously cold-rolled or hot-rolled by the tandem rolling mill, thereby suppressing the meandering increase of the steel strip in the tandem rolling mill and It is possible to prevent rolling troubles such as drawing rupture of the steel strip caused by.

  By using the meandering control device and meandering control method according to the present invention, unintentional deformation of the steel strip (base material) without being affected by the use environment of fume, rolling coolant, etc., and on the entry side of the tandem rolling mill The occurrence of rolling trouble can be reduced by suppressing the meandering of the steel strip in the tandem rolling mill. In addition, since the accuracy and reliability of meandering control in tandem rolling mills can be improved, it contains not only ordinary steel strips that are cold-rolled or hot-rolled, but also thin materials with relatively thin materials and a large amount of silicon components. It is possible to continuously roll a metal strip having a relatively high risk of breakage, such as a high Si material, without rolling trouble.

  In the above-described embodiment, as the tandem rolling mill to which the meandering control device and the meandering control method according to the present invention are applied, a plurality of six-stage rolling mills having a pair of work rolls and two pairs of backup rolls are provided. Although the tandem rolling mill is exemplified, the present invention is not limited to this. The meandering control device and meandering control method according to the present invention can be applied to a tandem rolling mill provided with a plurality of units other than a six-stage rolling mill such as a four-stage rolling mill. In this case, the plurality of rolling mills constituting the tandem rolling mill may be of the same number of roll stages, or may be a combination of rolling mills of different roll stages. Further, in the tandem rolling mill to which the meandering control device and the meandering control method according to the present invention are applied, the number of stands may be plural, and the number of roll stages of each rolling mill, the rolling method such as cold rolling or hot rolling, etc. There is no particular question.

  In the above-described embodiment, the differential tension of the steel strip on the exit side of the rolling mill has been exemplified by subtracting the drive side tension from the work side tension. However, the present invention is not limited to this, and the differential tension is determined from the drive side tension. The work side tension may be reduced. In this case, the reduction leveling amount of each rolling mill of the tandem rolling mill is controlled so that the driving side tightening amount becomes larger than the work side tightening amount if the differential tension exceeds the upper limit value of the target range. If the differential tension is less than the lower limit of the target range, the work side tightening amount may be controlled to be larger than the drive side tightening amount. When the differential tension is within the target range, the reduction leveling amount may be controlled as in the above-described embodiment.

  Furthermore, in the above-described embodiment, the correction value based on the above-described formula (1) is added to the center value, the upper limit value, and the lower limit value of the target range of the differential tension to correct the target range. However, the present invention is not limited to this. That is, the upper limit value and lower limit value of the target range of the tension ratio have a certain difference with respect to the center value, and by adding or subtracting a predetermined value to the center value, these upper limit value and lower limit value May be corrected.

  In the above-described embodiment, the steel strip is exemplified as the metal strip to be subjected to meandering control. However, the present invention is not limited thereto, and the metal strip that is meandering controlled by the meandering control device and meandering control method according to the present invention is other than steel. It may be a band of an iron alloy or a band other than an iron alloy such as copper or aluminum. That is, in the present invention, the metal strip to be subjected to meandering control may be any of a steel strip, an iron alloy strip other than the steel strip, and a metal strip other than the iron alloy strip, and the type of metal strip such as a steel type ( For example, strength and composition are not particularly limited.

  Further, the present invention is not limited by the above-described embodiment, and the present invention includes a configuration in which the above-described constituent elements are appropriately combined. In addition, all other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above-described embodiments are included in the present invention.

DESCRIPTION OF SYMBOLS 1 Rolling line 2 Uncoiler 3 Tandem rolling mill 3a, 3b, 3c, 3d Work roll 5 Steel strip 6 Coil 10 Meander control device 11a, 11b, 12a, 12b Tension meter 13, 14 Tension calculating part 15a, 15b, 16a, 16b Leveling Apparatus 17 Control part F1, Fi, Fi + 1, Fn Rolling mill L1, L2 Correlation line Rt Target range

Claims (6)

In a meandering control device for controlling meandering of the metal strip in a tandem rolling mill for rolling the metal strip,
Tension measuring means for measuring each tension at one end and the other end in the width direction of the metal strip on each rolling mill exit side of the tandem rolling mill,
It is the sum of the differential tension that is the difference between the tension at the one end and the tension at the other end, and the tension at the one end and the tension at the other end for each rolling mill exit side of the tandem rolling mill. An arithmetic processing means for calculating a total tension and calculating a tension ratio which is a ratio of the differential tension to the total tension;
The tension ratio targeted for preventing meandering of the metal strip in the rolling mill to be controlled according to the reduction leveling amount of the next rolling mill arranged in the subsequent stage of the rolling mill to be controlled among the tandem rolling mills And control the rolling leveling amount of the rolling mill to be controlled so that the tension ratio calculated corresponding to the outlet side of the controlled rolling mill is within the corrected target range. Control means for
A meandering control device comprising:   The control means corrects the center value of the target range according to the reduction leveling amount of the next rolling mill, and sets the upper limit value and the lower limit value of the target range after correction centered on the corrected center value. The meandering control apparatus according to claim 1, wherein:   The control means multiplies an influence coefficient indicating an influence of a reduction leveling amount of the next rolling mill on the tension ratio on the outlet side of the controlled rolling mill and a reduction leveling amount of the next rolling mill, and the target range. The meandering control device according to claim 1, wherein the correction value is calculated by adding the correction value to a center value, an upper limit value, and a lower limit value of the target range, and the target range is corrected. . In a meandering control method for controlling meandering of the metal strip in a tandem rolling mill for rolling the metal strip,
A tension measuring step for measuring each tension at one end and the other end in the width direction of the metal strip on the rolling mill exit side of the tandem rolling mill;
It is the sum of the differential tension that is the difference between the tension at the one end and the tension at the other end, and the tension at the one end and the tension at the other end for each rolling mill exit side of the tandem rolling mill. An arithmetic processing step for calculating a total tension and calculating a tension ratio that is a ratio of the differential tension to the total tension;
The tension ratio targeted for preventing meandering of the metal strip in the rolling mill to be controlled according to the reduction leveling amount of the next rolling mill arranged in the subsequent stage of the rolling mill to be controlled among the tandem rolling mills A correction step for correcting the target range of
A control step of controlling a reduction leveling amount of the rolling mill to be controlled so that the tension ratio calculated corresponding to the delivery side of the rolling mill to be controlled is within the corrected target range;
A meandering control method comprising:   The correction step corrects the center value of the target range according to the reduction leveling amount of the next rolling mill, and sets the upper limit value and the lower limit value of the target range after correction centered on the corrected center value. The meandering control method according to claim 4, wherein:   In the correction step, the target range is obtained by multiplying an influence coefficient indicating an influence of a reduction leveling amount of the next rolling mill on the tension ratio on the outlet side of the controlled rolling mill and a reduction leveling amount of the next rolling mill. 6. The meandering control method according to claim 4, wherein the correction value is calculated and the correction value is added to a center value, an upper limit value, and a lower limit value of the target range to correct the target range. .

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