JP3545541B2 - Meandering control method in plate rolling - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a meandering control method for securing a stable threading property of a rolled material during rolling in a tandem rolling operation of a metal plate.
[0002]
[Prior art]
Tandem rolling of plate material is a process that can mass-produce high-precision thin plates.Tension can be applied to the rolled material between the rolling mills that constitute the tandem rolling mill row, enabling extremely stable rolling operation It is. When tension is applied to the rolled material, for example, even if there is a deviation from the optimum value to some extent in the difference between the set values of the pressing device on the working side and the driving side (hereinafter abbreviated as “rolling leveling”), it does not matter. The difference between the right and left elongation rates is not changed as is, but the right and left elongation differences are suppressed by the redistribution of the tension. However, since the forward and backward tensions cannot be applied to the leading and trailing ends of the rolled material, the stabilizing action due to the tension is reduced by half, and a passing-through accident is likely to occur. In particular, when the vehicle passes the rear end, a pass-through accident called butt squeezing often occurs, and a rolling-down control method called meandering control or squeezing squeeze control has been conventionally implemented.
[0003]
In the following description, the working side and the driving side are often simply represented by “left, right” in many cases. Therefore, for example, the "left-right difference of the rolling reduction value" means the difference between the working side and the driving side of the rolling reduction value. In the present invention, the passage of the rolled material shifted from the mill center in the width direction is referred to as “meandering”.
[0004]
Butt drawing is considered to be caused mainly by meandering of the material due to the difference in elongation between the working side and the drive side in the vicinity of the rear end of the rolled material. It is a conventional meandering control method to execute the control of the left-right difference of the rolling reduction value of the rolling mill, that is, the leveling control, from the time when the rolling machine comes out of the immediately preceding rolling mill. As the detection end at this time, a detection signal of the off-center amount of the plate by the meandering sensor or the left-right difference in the rolling load of the rolling mill is used.
[0005]
For example, Japanese Patent Application Laid-Open No. 59-191510 discloses a technique in which a meandering detector on the entry side of a rolling mill detects a meandering amount of a rolled material and performs leveling control. Also in the case of this technique, a technique of detecting a meandering amount and performing leveling control is disclosed. Also in the case of this technology, the meandering amount itself hardly shows a large change due to the tension acting on the rolled material during the tandem rolling as described above, so that it is possible to actually perform a significant rolling leveling control. , After the time when the rear end of the rolled material exits the immediately preceding rolling mill. As means for detecting the meandering of the rolled material, a meandering sensor (width direction passing position measuring device) as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 59-191510 or a difference in the rolling load of the rolling mill can be used. Are used.
[0006]
[Problems to be solved by the invention]
In the conventional meandering control method as described above, since the control is started from the time when the rear end of the rolled material comes out of the immediately preceding rolling mill, the operation time of the substantial control is short, and there are cases where it is not possible to prevent the tail drawing. is there. Also, when there is a deviation from the optimum value in the rolling leveling of the rolling mill, when the rear end of the rolled material exits the immediately preceding rolling mill, the backward tension that has been applied up to that point is lost, and the tension of the tension is lost. Since the compensation effect due to the left-right difference disappears, sudden meandering starts, and it is often too late to start the rolling leveling control after the phenomenon appears.
[0007]
In the present invention, instead of starting the control from the time when the rear end of the rolled material exits the immediately preceding rolling mill, in a steady rolling state before reaching the rear end of the rolled material, the reduction leveling of each rolling mill in the tandem rolling mill row is performed. A method to keep the optimal state.
[0008]
[Means for Solving the Problems]
The gist of the present invention is that a roll having a roll axis parallel to a roll axis of a rolling mill is provided between two or more rolling mills and at least one of the rolling mills, and is rotated by contact with a rolled material. A movably supported tension measuring roll is provided, and the vertical force applied to the tension measuring roll by the rolling direction tension acting on the rolled material can be independently detected on the working side and the drive side. Meandering of a tandem plate rolling mill provided with a measuring device having a structure capable of detecting a force in the roll axis direction acting on the tension measuring roll from the rolled material and a device for measuring a width direction passing position of the rolled material. In the control method, from the output of the width direction threading position measurement device, the width direction threading position of the rolled material at the position of the tension measurement roll between the rolling mills is directly detected or estimated, and this and the tension measurement roll are used. In the vertical direction From the detected values of the working side and the drive side of the force and the detected value of the force in the roll axis direction acting on the tension measuring roll from the rolled material, the roller truly acts on the rolled material at the position of the tension measuring roll. The difference between the working side and the driving side of the tension is calculated, and the difference in the tension falls within a predetermined allowable range. In addition, the force in the roll axis direction applied to the tension measuring roll is a predetermined allowable range. A meandering control method in sheet rolling, characterized in that a difference between a set value of a rolling reduction on a working side and a set value of a reduction on a driving side of each rolling mill is controlled so as to fall within a range.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The biggest change caused by the trailing end of the rolled material leaving the immediately preceding rolling mill is, of course, the absence of back tension. Therefore, if a sudden meandering starts at this time, it is presumed that the meandering has deviated from the optimum rolling leveling value of the rolling mill, and this has been compensated for by the left-right difference in the back tension. For this reason, during steady rolling before reaching the rear end of the rolled material, it is necessary to make the left-right difference in the tension acting on the rolled material on the entrance side and the exit side of each rolling mill as close to zero as possible. It is considered to be a decisive factor in accident prevention. For this purpose, an operation may be performed in which the difference between the left and right tensions acting on the rolled material on the entrance side and the exit side of each rolling mill is detected, and the difference is reduced to near zero.
[0010]
FIG. 1 shows an algorithm of a preferred embodiment of the meandering control method of the present invention. The algorithm of FIG. 1 is intended for a tandem rolling mill equipment row in which, for example, as shown in FIG. 2, tension measuring rolls 2a to 2c and width direction threading position measuring devices 3a to 3c are provided between stands. This is a meandering control method. From the outputs of the width direction passing position measuring devices 3a to 3c provided between the stands, the width direction passing position of the rolled material 4 at the positions of the tension measuring rolls 2a to 2c also provided between the stands is directly detected or presume. The tension measuring roll is configured to be capable of measuring right and left independent tension and a force in a roll axis direction (hereinafter, referred to as a thrust force). From the measured values of the left and right tension and the thrust force and the widthwise position of the rolled material in the width direction, a left-right difference in the tension truly acting on the rolled material is calculated.
[0011]
Now, any No. i rolling mill and No. The looper type tension measuring device as shown in FIG. 4 will be described in more detail by taking into account the interval between the i + 1 rolling mills. When the value obtained by converting the load cell load of the rolled material tension measuring device into a load in the vertical direction in consideration of the looper angle and extracting the difference between the working side and the drive side is R _dfi , R _dfi acts on the rolled material. _Not only the tension difference σ _dfi, but also the thrust force S _i acting on the tension measuring roll (positive when acting on the tension measuring roll from the rolled material toward the working side from the driving side), and the width direction of the rolled material The influence of the plate position, that is, the material off-center amount _xci is also included, and the following relational expression is established.
R _dfi = [{b ² / (6a _Li )} σ _dfi + (2 / a _Li ) σ _i bx _ci ]
_{× (sinθ fi + sinθ b (} i + 1)) h i + (2 / a Li) r Li S i
(1)
Here, b is the plate width of the rolled material, a _Li is the distance between the roll fulcrums for tension measurement, σ _i is the tension per unit cross-sectional area of the rolled material (hereinafter referred to as unit tension), θ _fi and θ _{b (i + 1) )} reference angle (Fig. 3 forming the first i delivery side of the rolling mill and the i + 1 the plate surface of the entry side of the rolling mill is a horizontal plane as a boundary tension measuring roll), h _i is the thickness of the side exits the i mill, r _Li is the roll radius for tension measurement.
[0012]
From equation (1), even if the R _dfi is measured, if the material off-center amount x _ci in the thrust force S _i and looper position acting on the tension measuring roll is unknown, acting exactly rolled material It turns out that it is impossible to determine the tension.
[0013]
Generally, the rolling operation is carried out with the aim of making _xci zero, but in reality there is an error of about 10 to 20 mm, which has a considerable effect on the estimation accuracy of the tension σ _dfi acting on the rolled material. Effect. FIG. 4 is a schematic plan view of the rolled material 4 during rolling existing between the roll axis position 6 of the upstream rolling mill and the roll axis position 7 of the downstream rolling mill as viewed in the width direction. However, as shown in the figure, for example, when the widthwise passing position of the rolled material between the stands is shifted in the opposite direction between the upstream side and the downstream side, the tension measuring roll applies the thrust force from the rolled material to the tension measuring roll. Acts. This means that while the velocity vector 13 of the rolled material 4 has a small but parallel component 15 to the roll axis in addition to the component in the direction perpendicular to the roll axis, the circumferential velocity vector 14 of the tension measuring roll is always Since there is only a component perpendicular to the roll axis, a slip speed corresponding to the roll axis direction speed component 15 of the rolled material is generated between the roll and the tension measurement roll, and a friction force generated in the slip direction is generated by the tension measurement roll. A thrust force acts from the rolled material.
[0014]
For example, when x _ci = 10 mm, a _Li = 2000 mm, and b = 1000 mm, the tension difference σ _dfi is estimated while ignoring the influence of x _ci from the evaluation of the term in [] on the right side of equation (1). , 12% of the unit tension σ _i . Further, the thrust force S _i which acts on tension measuring rolls is generally believed to be evaluated by the following formula obtained by multiplying the constants said thrust coefficient in the vertical direction of the resultant force acting on the tension measuring roll.
_{S i = γσ i bh i (} sinθ fi + sinθ b (i + 1)) (2)
Here, γ is a thrust coefficient. Substituting equation (2) into equation (1), when evaluated, when a 150mm tension measuring roll radius _{r Li} addition to the above condition, even if the thrust coefficient of 0.05, the unit tension ignoring thrust force _{S i} This results in an error of 9% of σ _i .
[0015]
If the reduction leveling control was performed to null the laterality sigma _dfi tension acting on the rolled material, it is common to change the material off-center amount x _ci and thrust force S _i, the change detection at all if executing the control without the case according to the above example, this control will contain the essential error of about ± 0.1σ _i with respect to the target value sigma _dfi, abolish butt aperture accident It is impossible to implement sufficient meandering control as much as possible. It is clear that it is not important to set R _dfi = 0, but to set σ _dfi = 0, in order to prevent the _passing -through accident.
[0016]
As described above, in _order to accurately detect σ _dfi and perform control for _setting σ _dfi = 0, a rolled material tension measuring device having a tension detector independently for each of the working side and the driving side is used. Detecting the left-right difference of the load applied to the tension measuring device, directly detecting or estimating the widthwise passing position of the rolled material at the position of the tension measuring device, and detecting the thrust force acting on the tension measuring device. Obviously, it is essential to detect even
[0017]
After the left-right difference of the tension acting on the rolled material is calculated as described above, the rolling leveling control of each rolling mill is performed with the target that the difference in tension becomes a predetermined value. As the predetermined target value at this time, in general, the target is a right-left difference of zero, but a predetermined target value near zero may be set according to the learning result of the operation results. Even if such control is performed, it is rare that the target value is completely coincident with the target value. Therefore, an allowable range of the right-left difference in tension is provided near the target value, and when the allowable value is exceeded, the draft leveling is performed. It is realistic to perform the control.
[0018]
Next, the thrust force acting on the tension measuring roll is detected, and the rolling leveling control of each rolling mill is performed so that the axial force becomes a predetermined value.
In the state as shown in FIG. 4 in which a thrust force is generated, the main shaft 12 of the tension acting on the rolled material between the stands is oblique to the rolled material between the stands as shown in FIG. In addition, even if the tension distribution 11 of the rolled material at the tension measurement roll position is uniform, the tension distribution 9 at the upstream rolling mill position and the tension distribution 10 at the downstream rolling mill position become non-uniform in the direction shown in the drawing. . Such an unbalance of the tension cannot be detected from the measurement of the vertical load applied to the tension measuring roll 2 described above, and the thrust force acting on the tension measuring roll is detected, and this is detected as zero. The detection and control can be performed for the first time by the method of the present invention in which the rolling leveling control as described above is simultaneously performed.
[0019]
By the way, the target value of the thrust force acting on the tension measuring roll is basically zero, but depending on the error of the parallelism between the tension measuring roll axis and the roll axis of the rolling mill, a predetermined value near zero is determined. It may be more stable to target the value of Even if such control is performed, it is rare that the target value is completely matched. Therefore, an allowable range of the thrust force is provided near the target value, and when the allowable value is exceeded, the rolling leveling control is performed. It is preferable to adopt a method of implementing.
[0020]
Further, in the algorithm of FIG. 1, a control loop for setting the thrust force acting on the tension measuring roll to a predetermined value is positioned outside the control loop for setting the left-right difference of the tension acting on the rolled material to a predetermined value. However, as a control method, the reverse may be performed, or a pressure leveling operation for simultaneously reducing the right-left difference in tension and the thrust force to zero may be performed at a stretch.
[0021]
【Example】
A 7-stand tandem mill as shown in FIG. 5, which has tension detectors independently between the working side and the driving side between all the stands 1a to 1g, and is capable of detecting a vertical load and a roll axial load. Detecting devices 3a to 3d which have the rolls 2a to 2f and which can measure the widthwise passing position of the rolled material between the four stands 1d to 1g in front of the rolling mill in a continuous manner from the most downstream rolling mill. The meandering control was carried out using the tandem rolling mill group that was used.
[0022]
Initially, the tension difference σ _dfi acting on the rolled material is estimated by assuming that the material off-center amount is always zero, using only the measured value of the vertical load of the tension measuring roll, and rolling down the target with σ _dfi = 0. Although leveling control was performed, the threading condition at the rear end of the rolled material did not reach complete stability.
[0023]
Therefore, an estimated value of the material off-center amount at the position of the tension measuring roll is calculated based on the output of the width direction passing-through position measuring devices 3a to 3d of the rolled material, and this value and the vertical and axial load of the tension measuring roll are calculated. From equation (1), the tension difference σ _dfi acting on the rolled material was estimated using equation (1), and the rolling leveling control of each rolling mill was performed with σ _dfi = 0 as a target. Furthermore, as a result of simultaneously executing the draft leveling control with the aim of reducing the measured value of the roll axial load acting on the tension measuring roll to zero, the passing of the rear end of the rolled material including the downstream rolling mill was substantially completed. It was completely stabilized.
[0024]
【The invention's effect】
By using the meandering control method of the present invention, it is possible to optimize the rolling leveling of each rolling mill in the tandem rolling mill row during the steady rolling, and as a result, at the time of threading, including at the time of rear end rolling of the rolled material. There are almost no accidents, and the working rate and yield can be greatly improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing an algorithm of a meandering control method according to the present invention.
FIG. 2 is a schematic view showing an example of a tandem plate rolling mill equipment row as a premise of the present invention.
FIG. 3 is a side view showing an angle between a rolling material between rolling mills and a horizontal plane.
FIG. 4 is a plan view illustrating a mechanism in which a roll axial load is applied to a tension measuring roll between arbitrary stands.
FIG. 5 is a schematic view showing a tandem plate rolling mill equipment row according to an embodiment of the present invention.
[Explanation of symbols]
1a to 1g Rolling mills 2a to 2f Rolled material tension measuring device 3a to 3d Width direction threading position measuring device 4 Rolled material 5 Rolling direction 6 Roll axis center position of upstream rolling mill between any rolling mills 7 Any rolling mill Roll axis position of downstream rolling mill between 8 Roll axis position of tension measuring roll between arbitrary rolling mills 9 Tension distribution of upstream rolling mill position 10 Tension distribution of downstream rolling mill position 11 Tension measuring roll position Tension distribution 12 in the rolling mill Main shaft 13 of the tension acting on the rolled material between the rolling mills 13 Speed vector 14 of the rolled material at the position of the roll for tension measurement Peripheral speed vector 15 of the roll for tension measurement Speed component in the roll axis direction of the rolled material

Claims (1)

Between two or more rolling mills and at least one of the rolling mills, the rolling mill has a roll axis parallel to the roll axis of the rolling mill, and is rotatably supported in contact with the rolled material. A tension measuring roll is provided, and a vertical force applied to the tension measuring roll by the rolling direction tension acting on the rolled material can be independently detected on the working side and the drive side, and further, the tension In a meandering control method of a tandem plate rolling mill provided with a measuring device having a structure capable of detecting a force in a roll axis direction acting on a measuring roll from a rolled material and a device for measuring a width direction threading position of a rolled material, From the output of the direction threading position measuring device, the width direction threading position of the rolled material at the position of the tension measuring roll between the rolling mills is directly detected or estimated, and this and the vertical direction loaded on the tension measuring roll. The working side of the power and the drive From the detected value of the side and the detected value of the force in the roll axis direction acting on the tension measuring roll from the rolled material, the working side and the drive of the tension truly acting on the rolled material at the position of the tension measuring roll The difference between the tensions is calculated so that the tension difference falls within a predetermined allowable range, and the force in the roll axis direction applied to the tension measuring roll also falls within a predetermined allowable range. A meandering control method in plate rolling, wherein a difference between a set value of a rolling reduction on a working side and a set value of a reduction on a driving side of each rolling mill is controlled.

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