JP4288888B2 - Strip meander control device and meander control method for tandem rolling mill - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a meandering control device and a meandering control method for preventing meandering of a strip in a tandem rolling mill.
[0002]
[Prior art]
Conventionally, in order to prevent strip meandering in a tandem rolling mill, a method of controlling the leveling of each stand according to the following equation (1) is known.
ΔT _{i, i + 1} = AΔS _li + BΔW + CΔC (1)
Where ΔT _{i, i + 1} : i-th stand forward differential tension, ΔS _li : i-th stand leveling amount, ΔW: plate displacement in the width direction, ΔC: plate width direction crown difference, A, B, C : Constant determined by rolling schedule An example of rolling a strip based on the formula (1) will be described with reference to FIG. In FIG. 4, 101 is a rolling mill, 102 is a strip, 103 is a rolling direction, 104 is a tension meter, 105 is a meandering correction device, 106 is a leveling device, 107 is a differential tension signal, and 108 is a biasing device.
[0003]
Here, the forward differential tension ΔT _{i, i + 1} is detected from the tensiometer 104 installed between the i-th stand and the i + 1-th stand. The differential tension is obtained by measuring the tensions at both ends of the strip (working side end and driving side end) in one stand and calculating the difference. Further, ΔW is detected by a CPC device (not shown) installed between the i-th stand and the i + 1-th stand, and a crown meter (not shown) installed between the i-th stand and the i + 1-th stand. To detect ΔC. BΔW + CΔC is used as an output of the bias signal device 108, ΔS _li is obtained by AΔS _li = ΔT _{i, i + 1} − (BΔW + CΔC), and this signal is sent to the meandering correction device 105. The meandering correction device 105 controls the leveling of the i-th stand by the leveling device 106 based on the ΔS _li signal.
[0004]
Japanese Patent Application Laid-Open No. 63-188415 discloses that in controlling the leveling of the i-th stand, not only the i-th stand but also the forward differential tension of the i + 1th stand, the amount of displacement in the width direction of the strip, and the width of the strip A technique for detecting the crown difference in the direction and controlling the leveling amount of the i-th stand based on these is disclosed.
[0005]
However, in these leveling control methods, it is necessary to measure the shift amount ΔW in the width direction of the plate between the rolling stands or on the exit side of the rolling stand. In measuring this ΔW, fume, rolling coolant, etc. In many cases, the measurement was difficult due to the influence of the usage environment.
In the leveling control method described above, leveling control is performed using an evaluation formula based on the differential tension, the displacement in the width direction of the plate, and the crown difference in the width direction of the plate. Since the relationship between the differential tension and the leveling is not a linear relationship, there is a problem in the accuracy of the evaluation formula, and the evaluation method of the optimum leveling value needs to be improved.
[0006]
Therefore, in the conventional meandering control method of the strip disclosed in Japanese Patent Application Laid-Open No. 11-151514, as shown in FIG. 5, the plate of the strip 202 is detected by an electromagnetic type position detector 205 installed on the i-th stand exit side. Measuring the width and meandering amount, and measuring the total tension and differential tension of the strip 202 by a tension meter 204 installed on the i-th stand exit side, and controlling the leveling of the i-th stand based on these measured values; And a step of measuring the amount of meandering of the strip 202 by the electromagnetic type position detector 205 installed on the entrance side of the first stand, and controlling the position of the uncoiler 208 based on this measured value. In FIG. 5, reference numeral 201 denotes a rolling mill, 203 denotes a rolling direction, 206 denotes a computing unit, and 207 denotes a leveling device. Note that the total tension is obtained by measuring the tensions at both ends of the strip (working side end and driving side end) on one stand and calculating the sum.
[0007]
Thus, by measuring the plate width and meandering amount of the strip 202 by the electromagnetic type position detector 205, it is possible to measure the plate width and meandering amount without being affected by the use environment such as fume and rolling coolant. In addition, the leveling of the i-th stand is controlled based on the plate width, the meandering amount, the total tension and the differential tension of the strip 202, and at the same time, the position of the uncoiler 208 is controlled at the rolling mill entrance side to center the strip 202. By doing so, meandering due to leveling setting failure can be prevented with high accuracy.
[0008]
[Problems to be solved by the invention]
However, the strip meandering control method disclosed in Japanese Patent Laid-Open No. 11-151514 shown in FIG. 5 has the following problems.
That is, on the entry side of the rolling mill, a high tension is applied to the strip 202 for rolling, and the strip 202 is restrained on the rolling mill side, so that the position of the uncoiler 208 is controlled on the entry side of the rolling mill. If the strip 202 is centered, the strip base material may be deformed.
[0009]
Further, although the leveling of the i-th stand is controlled based on the plate width of the strip 202, the amount of meandering, the total tension, and the differential tension, since the ratio of the differential tension to the total tension is not taken into consideration, the size of the ratio is large. Depending on the case, meandering of the strip may not be prevented, and in this case, it is not possible to prevent the biting failure of the strip stand or the rupture of the drawing.
[0010]
Therefore, the present invention has been made in view of the above-mentioned problems, the purpose thereof is not affected by the use environment such as fume, rolling coolant, and without causing deformation of the strip base material, An object of the present invention is to provide a meandering control device and a meandering control method for a strip in a tandem rolling mill that can effectively prevent the meandering of the strip.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the strip meandering control apparatus in the tandem rolling mill according to claim 1 of the present invention is a strip work on the rolling stand exit side of the tandem rolling mill having an uncoiler for winding the strip on the inlet side. A tension measuring means for measuring each of the side tension and the driving side tension; and a difference tension between the strip working side tension and the strip driving side tension based on each tension of the strip measured by the tension measuring means; A ratio calculation means for calculating a ratio of the differential tension to the total tension based on the differential tension and the total tension, and calculating a ratio of the differential tension to the total tension based on the differential tension and the total tension; level ratio relative to the total tension in said calculated difference tension before Ki圧 extending stand to be within a predetermined range It is characterized in that a leveling control means for performing ring control.
[0012]
According to a second aspect of the present invention, there is provided a strip meandering control method in a tandem rolling mill according to the present invention, wherein the work side tension and driving side of the strip on the rolling stand exit side of the tandem rolling mill provided with an uncoiler that winds the strip on the entry side. A differential tension between the strip working side tension and the strip driving side tension is obtained on the basis of the step of measuring each tension and each measured tension of the strip, and the total tension which is the sum of the strip working side tension and the strip driving side tension is obtained. Obtaining a tension, and calculating a ratio of the differential tension to the total tension based on the differential tension and the total tension; and a ratio of the calculated differential tension to the total tension being within a predetermined range. And a step of performing leveling control of the rolling stand.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram of a meander control apparatus according to the present invention. FIG. 2 is a graph showing the rate of occurrence of the ratio of the differential tension to the total tension when a plurality of strips are rolled and the state of drawing fracture. FIG. 3 shows a meandering correction operation by a meandering correction roll when the strip meanders, (A) is a schematic side view, (B) is a schematic plan view, and (C) is a schematic perspective view.
[0014]
In FIG. 1, a strip 2 is unwound from an uncoiler (not shown), conveyed in the direction of arrow A, and rolled by a tandem rolling mill including a plurality of rolling stands 1. Then, (in the case of FIG. 1, the delivery side of the i stand and the i + 1 stand) the exit side the rolling stand 1, the working side tensiometer 3a and the strip 2 for measuring the working side tension T _ws of the strip 2 a drive-side tensiometer 3b for measuring the driving-side tension T _DS is installed in. These work-side tension meter 3a and drive-side tension meter 3b constitute "tension measuring means" defined in claim 1. As each of the tension meters 3a and 3b, a conventionally known device is used that measures a vertical load by, for example, a load cell, and detects a strip tension based on a fixed contact angle of the strip 2.
[0015]
These tensiometers 3a and 3b are provided in order to keep the tension between the rolling stands 1 and 1 appropriately, but in the present invention, they are also used for the meandering control of the strip 2.
The working side tensiometer 3a and the drive-side tensiometer 3b, together with obtaining the difference between tension [Delta] T _i of the strip working side tension T _ws and strip driving side tension T _DS, strip working side tension T _ws and strip driving side tension T _DS calculated on the total tension T _i which is the sum of, further, a ratio calculator 4 for calculating the ratio [Delta] T _i / T _i for the total tension T _i of the differential tension [Delta] T _i is connected. The ratio calculator 4 constitutes “ratio calculator” defined in claim 1.
[0016]
Further, the ratio calculator 4 includes a work-side leveling amount ΔS _WS and a driving-side leveling amount in which the ratio ΔT _i / T _{i of} the differential tension ΔT _i calculated by the ratio calculator 4 to the total tension T _i falls within a predetermined range. A control leveling computing unit 5 for calculating ΔS _DS is connected. The control leveling computing unit 5 outputs the work side leveling amount ΔS _WS and the drive side leveling amount ΔS _DS to each of the work side reduction position controller 6a and the drive side reduction position controller 6b provided in the rolling stand 1, Leveling control of the rolling stand 1 is performed. This control leveling computing unit 5 constitutes “leveling control means” defined in claim 1.
[0017]
Next, a method for controlling the meandering of the strip 2 will be specifically described.
In FIG. 1, the work side tension T _ws and the drive side tension T _DS of the strip 2 measured by the work side tension meter 3 a and the drive side tension meter 3 b installed on the exit side of the i-th stand are supplied to the ratio calculator 4. Sent out. In the ratio calculator 4, the differential tension ΔT _i (= T _ws −T _DS ) is calculated based on the work side tension T _ws and the driving side tension T _DS , and the total tension T _i (= T _ws + T _DS ). Is calculated. Then, the ratio calculator 4 calculates a ratio ΔT _i / T _i of the differential tension ΔT _i with respect to the total tension T _i . Then, the ratio calculator 4 sends the ratio ΔT _i / T _i to the control leveling calculator 5.
[0018]
In the control leveling calculator 5, the work-side leveling amount ΔS _WS and the driving-side leveling amount ΔS that the ratio ΔT _i / T _{i of} the differential tension ΔT _{i to} the total tension T _i calculated by the ratio calculator 4 is within a predetermined range. Calculate _DS . Referring now to FIG. 2 is a graph showing the incidence and diaphragm rupture conditions of a ratio to the total tension difference tension in the case of rolling a plurality of strips, the ratio [Delta] T _i to the total tension T _i of the difference tension [Delta] T _i / T _i is the case when greater than 0.2 and -0.2 smaller, it can be seen that the diaphragm rupture occurs. Accordingly, if the leveling control of the rolling stand is performed so that the ratio ΔT _i / T _{i of} the differential tension ΔT _{i to} the total tension T _i is −0.2 or more and 0.2 or less, it is possible to prevent drawing breakage due to strip meandering. Understood. As described above, in the present invention, since the leveling control is performed in consideration of the ratio of the differential tension ΔT _{i to} the total tension T _i , the strip is compared with the case where the leveling control is simply performed based on the differential tension T _i . Meandering can be surely prevented, and inadequate biting at the stand of the strip and squeezing breakage can be prevented.
[0019]
That is, when the ratio ΔT _i / T _{i of} the differential tension ΔT _{i to} the total tension T _i calculated by the ratio calculator 4 is greater than 0.2, the control leveling calculator 5 calculates the work-side leveling amount ΔS _WS. calculating the working side tightening amount G _WS, calculate the 0 as the drive-side leveling amount [Delta] S _DS, work 0 as a working side tightening amount G _WS and drive side leveling amount [Delta] S _DS as a working side leveling amount [Delta] S _WS It outputs to each of the side pressure reduction position controller 6a and the drive side pressure reduction position controller 6b, and performs leveling control of the i-th stand. The control leveling calculator 5, when the ratio [Delta] T _i / T _i for all the tension T _i of the difference tension [Delta] T _i calculated by the ratio calculation unit 4 is -0.2 to 0.2, the working side The work side tightening amount 0 is calculated as the leveling amount ΔS _WS , 0 is calculated as the drive side leveling amount ΔS _DS , and the work side tightening amount 0 as the work side leveling amount ΔS _WS and the drive side leveling amount ΔS _DS are calculated. 0 is output to each of the work side reduction position controller 6a and the drive side reduction position controller 6b to perform leveling control of the i-th stand. Further, when the ratio ΔT _i / T _{i of} the differential tension ΔT _i with respect to the total tension T _i calculated by the ratio calculator 4 is smaller than −0.2, the control leveling calculator 5 calculates the work-side leveling amount ΔS _WS. calculating the working side tightening amount 0 as to calculate the G _DS as the drive-side leveling amount [Delta] S _DS, the G _DS as a working side leveling amount [Delta] S working side tightening amount 0 and the drive-side leveling amount [Delta] S _DS as _WS It outputs to each of the work side reduction position controller 6a and the drive side reduction position controller 6b to perform leveling control of the i-th stand.
[0020]
As described above, when the ratio ΔT _i / T _i of the differential tension ΔT _i with respect to the total tension T _i is larger than 0.2, the i th based on the work side tightening amount G _WS as the work side leveling amount ΔS _WS . leveling control of the stand is performed, if the ratio [Delta] T _i / T _i for all the tension T _i of the difference tension [Delta] T _i is -0.2 to 0.2, it is changed pressing position with the work side and drive side If the ratio ΔT _i / T _{i of} the differential tension ΔT _{i to} the total tension T _i is smaller than −0.2, level control of the i-th stand is performed based on G _DS as the drive side leveling amount ΔS _DS. Therefore, the leveling control of the rolling stand is performed so that the ratio ΔT _i / T _{i of} the differential tension ΔT _{i to} the total tension T _i becomes −0.2 or more and 0.2 or less. For this reason, it is possible to reliably prevent drawing breakage due to strip meandering.
[0021]
Here, also for the leveling control of the i + 1 stand, as in the leveling control of the i stands, the range ratio [Delta] T _i / T _i is -0.2 to 0.2 to the total tension T _i of the difference tension [Delta] T _i Leveling control is performed so that
In the conventional leveling control as shown in FIG. 5, when the strip 2 meanders with respect to the center of the rolling stand 1 as shown in FIG. 3, the uncoiler 208 shown in FIG. Of the strip 2 by tilting a meandering correction roll 7 (moving the steel sheet by tilting the axis with respect to the rolling surface) as shown in FIG. I was doing centering. When such a meandering control method for the strip 2 is adopted, a high tension is applied to the strip 2 for rolling on the entrance side of the rolling stand 1 and the strip 2 is restrained on the rolling stand 1 side. Deformation of the strip base material occurred, and there was a high possibility that rolling troubles such as drawing fracture would occur.
[0022]
However, as in the present invention, when the leveling control of the rolling stand 1 such that the ratio [Delta] T _i / T _i for all the tension T _i of the difference tension [Delta] T _i is -0.2 to 0.2, the strip meander Therefore, the amount of meandering correction due to the operation of the meandering correction roll 7 and the uncoiler 208 on the entrance side of the rolling mill can be limited. For this reason, deformation of the strip base material does not occur. However, the meandering correction by the operation of the meandering correction roll 7 and the uncoiler 208 on the entrance side of the rolling mill in a range where the deformation of the strip base material does not occur is possible.
[0023]
Further, since it is not necessary to measure the amount of displacement of the strip 2 in the width direction between the rolling stands 1 and 1 or on the exit side of the rolling stand 1, it is not affected by the use environment such as fume and rolling coolant.
As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change can be made.
[0024]
For example, the leveling control is performed so that the ratio ΔT _i / T _i of the differential tension ΔT _{i to} the total tension T _{i is in} the range of −0.2 or more and 0.2 or less. The range can be appropriately changed in consideration of the plate thickness, unit tension, and the like.
[0025]
【The invention's effect】
As described above, according to the meander control apparatus and meander control method for preventing meandering of the strip in the tandem rolling mill according to the present invention, the working side tension and driving side tension of the strip on the rolling stand exit side of the tandem rolling mill are reduced. Measure each, and based on each measured tension of the strip, obtain the differential tension between the strip working side tension and the strip driving side tension, and obtain the total tension that is the sum of the strip working side tension and the strip driving side tension, Based on the differential tension and the total tension, a ratio of the differential tension to the total tension is calculated, and the leveling of the rolling stand is performed so that the calculated ratio of the differential tension to the total tension is within a predetermined range. Because it is controlled, it is not affected by the use environment such as fume and rolling coolant, and the strip base material Without causing shape, it is possible to prevent meandering of the strip effectively.
[Brief description of the drawings]
FIG. 1 is a system diagram of a strip meandering control apparatus according to the present invention.
FIG. 2 is a graph showing the rate of occurrence of the ratio of the differential tension to the total tension when a plurality of strips are rolled and the state of drawing fracture.
FIG. 3 shows a meandering correction operation by a meandering correction roll when a strip meanders, (A) is a schematic side view, (B) is a schematic plan view, and (C) is a schematic perspective view.
FIG. 4 is a schematic diagram for explaining a strip meandering control method of a conventional example.
FIG. 5 is a schematic diagram for explaining another conventional example of strip meandering control method;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rolling stand 2 Strip 3a Work side tension meter 3b Drive side tension meter 4 Ratio calculator (ratio calculation means)
5 Control leveling computing unit (leveling control means)
6a Work side roll position controller 6b Drive side roll position controller 7 Meander correction roll

Claims (2)

Tension measuring means for measuring the working side tension and the driving side tension of the strip on the rolling stand exit side of the tandem rolling mill equipped with an uncoiler that winds the strip on the entry side;
Based on each tension of the strip measured by the tension measuring means, a differential tension between the strip working side tension and the strip driving side tension is obtained, and a total tension which is the sum of the strip working side tension and the strip driving side tension is obtained. A ratio calculating means for calculating a ratio of the differential tension to the total tension based on the differential tension and the total tension;
Tandem rolling mill ratio with respect to the total tension of the differential tension calculated by the ratio calculating means, characterized in that a leveling control means for leveling control before Ki圧 extending stand to be within a predetermined range Strip meander control device. Measuring the work side tension and the driving side tension of the strip on the rolling stand exit side of the tandem rolling mill equipped with an uncoiler that winds the strip on the entry side,
Based on each measured tension of the strip, a differential tension between the strip working side tension and the strip driving side tension is obtained, and a total tension which is a sum of the strip working side tension and the strip driving side tension is obtained. Calculating a ratio of the differential tension to the total tension based on the total tension;
A strip meandering control method for a tandem rolling mill, wherein the leveling control of the rolling stand is performed so that the calculated ratio of the differential tension to the total tension is within a predetermined range.

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