JPH1034220A - Method for controlling meandering in sheet rolling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate accidents at the time of passing a sheet through the mill and to improve working rate and yield by calculating difference in tension which act on a rolled stock in the position of a tension measuring roll between the operation side and drive side and controlling each rolling mill so that the difference is fallen in the allowable range. SOLUTION: By the output of devices 3a-3d for measuring the sheet passing position in the width direction of the rolled stock, the estimated value of the off-center amount of a material in the position of the tension measuring roll is calculated. The tension difference σdfi acting on the rolled stock is estimated using an equation from the estimated value above and the vertical and axial direction loads of the tension measuring roll and reducing/levelling control of each rolling mill is executed targeting σdfi =0. Furthermore, by targeting that the measured value of the load in the axial direction of roll which acts on the tension measuring roll becomes zero, reducing/leveling control is simultaneously executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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]

2. Description of the Related Art Tandem rolling of a sheet material is a process capable of mass-producing a high-precision thin sheet. Since tension can be applied to a rolling material between rolling mills constituting a tandem rolling mill row, it is very stable. Rolling operation is possible. When tension is applied to the rolled material, for example, even if there is some deviation from the optimum value in the difference between the set values of the screw-down device on the working side and the drive side (hereinafter abbreviated as the screw-down leveling), it does not matter. The difference between the right and left elongation rates is not directly changed, but the right and left differences in the elongation rates are suppressed by the redistribution of the tension. However, since the forward or backward tension cannot be applied to the leading and trailing ends of the rolled material, the above stabilizing action due to the tension is halved, and a passing-through accident is likely to occur. In particular, when passing through the trailing edge, a pass-through accident called squeezing often occurs,
Conventionally, a rolling-down control method called meandering control or trailing-edge restriction control has been implemented.

In the following description, in many cases, the work side,
The driving side is simply represented by “left, right”. Therefore, for example, the “left-right difference of the rolling reduction value” means a 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”.

It is considered that the tail drawing is caused mainly by the meandering of the material caused by the difference in elongation between the working side and the driving side near the rear end of the rolled material. It is a conventional meandering control method to execute control of the left-right difference of the rolling reduction value of the rolling mill, that is, leveling control, from the time when the rear end exits 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 difference in the rolling load of the rolling mill is used.

For example, Japanese Patent Application Laid-Open No. Sho 59-191510 discloses a technique in which a meandering detector on the entrance to 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, and therefore, 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 between the right and left of the rolling load of the rolling mill is used. Are used.

[0006]

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 exits the immediately preceding rolling mill, the operation time of the control is substantially reduced. In some cases, it may not be possible to prevent squeezing. Further, 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 had been acting until then disappears, and the compensation effect due to the left-right difference in tension disappears, so sudden meandering starts, and it is often too late to start rolling leveling control after that phenomenon appears .

According to the present invention, the control is not started from the time when the rear end of the rolled material exits the immediately preceding rolling mill, but rather in a steady rolling state before reaching the rear end of the rolled material, each of the rolling mills in the tandem rolling mill train A method for keeping the rolling leveling of the steel in an optimum state is presented.

[0008]

The gist of the present invention is that a roll axis parallel to the roll axis of the rolling mill is provided between two or more rolling mills and at least one of the rolling mills. A tension measuring roll rotatably supported in contact with the rolled material is provided, and a vertical force applied to the tension measuring roll by a rolling direction tension acting on the rolled material is applied to the working side. The drive side can be detected independently of each other, furthermore, 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 the width direction threading position of the rolled material. In the meandering control method of the deployed tandem plate rolling mill, the width direction passing position of the rolled material at the position of the tension measuring roll between the rolling machines is directly detected or estimated from the output of the width direction passing position measuring device. And
From the detected values on the working side and the drive side of the vertical force applied to the tension measuring roll and the detected values of the force in the roll axis direction acting on the tension measuring roll from the rolled material, the tension measurement is performed. The difference between the working side and the driving side of the tension truly acting on the rolled material at the position of the roll is calculated, and the tension difference falls within a predetermined allowable range. Meandering control in plate rolling characterized by controlling the difference between the reduction value of the rolling side on the working side and the reduction value of the driving side of each rolling mill, with the goal that the force in the roll axis direction to be loaded falls within a predetermined allowable range. Is the way.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The greatest 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 it has deviated from the optimum value of the rolling reduction of the rolling mill, and this has been compensated for by the left-right difference in the rear tension. For this reason, during steady rolling before reaching the rear end of the rolled material, it is necessary to make the right-left 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 zero.

FIG. 1 shows an algorithm of a preferred embodiment of the meandering control method of the present invention. The algorithm of FIG. 1 is, for example, as shown in FIG. 2, between the stands, the tension measuring rolls 2 a to 2 c and the width direction threading position measuring device 3 a to
This is a meandering control method for a tandem rolling mill equipment row in which 3c is deployed. 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 position 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 left and right 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 thrust force and the widthwise passing position of the rolled material, the left and right difference of the tension truly acting on the rolled material is calculated.

Now, when an arbitrary No. i rolling mill and No. i + 1
In consideration of the interval between rolling mills, a looper type tension measuring device as shown in FIG. 4 will be described in more detail as an example. The rolling material tension value obtained by extracting the difference between the drive-side working side in terms of the vertical load of the load cell load in consideration of the looper angle measuring device when the R _dfi, the R _dfi acting 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 the rolled material acts on the tension measuring roll from the drive side to the working side from the rolled material), and the width direction of the rolled material Plate position, that is, material off-center amount x
_Including the effect of _ci , the following relational expression holds. ^{_{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) where 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 sectional area of the rolled material (hereinafter referred to as unit tension), θ _fi And θb _{(i + 1)} are the i-th rolling mill exit side and the i-th
+1 angle between plate surfaces horizontal plane of the rolling mill inlet side (see FIG. 3), the thickness of the h _i is the delivery side of the i-th rolling mill, r _Li is roll radius for tension measurement.

From the equation (1), even if R _dfi is measured, if the thrust force S _i acting on the tension measuring roll and the material off-center amount x _{ci at the} looper position are unknown, the force acts on the rolled material accurately. It turns out that it is impossible to determine the tension that is applied.

In general, the rolling operation is carried out with the aim of making x _ci become zero. However, there is an error of about 10 to 20 mm in actuality, and this error _affects the estimation accuracy of the tension σ _dfi acting on the rolled material. Has a non-negligible 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 width direction passing position of the rolled material between the stands is shifted in the opposite direction between the upstream side and the downstream side, the thrust force from the rolled material is applied to the tension measuring roll. Works. this is,
In addition to the component in the direction perpendicular to the roll axis, the velocity vector 13 of the material 4
5 and the peripheral velocity vector 14 of the tension measuring roll.
Always has 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 the tension measurement roll is generated as a frictional force generated in the slip direction. , A thrust force acts from the rolled material.

For example, x _ci = 10 mm, a _Li = 2000 m
When m and b = 1000 mm, the tension difference σ _dfi can be obtained while ignoring the influence of x _ci from the evaluation of the terms in [] on the right side of the equation (1).
Is estimated, an error of 12% of the unit tension σ _i occurs. 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 (sin θ _fi + sin θ _{b (i + 1)} ) (2) where γ is a thrust coefficient. Equation (2) is replaced by equation (1)
When the roll radius r _Li for tension measurement was set to 150 mm in addition to the above conditions, the thrust coefficient was 0.0
Even if the value is 5, if the thrust force S _i is ignored, an error of 9% of the unit tension σ _i occurs.

When roll-down leveling control is performed to _reduce the right-left difference σ _dfi of the tension acting on the rolled material to zero, the material off-center amount x _ci and the thrust force S _i usually change. If the and executing the control without detecting any, if 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, ass aperture It is impossible to implement sufficient meandering control to eliminate the accident. 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.

As described above, in _order to accurately detect σ _dfi and perform control for _setting σ _dfi = 0, it is necessary to use a rolled material tension having a tension detector independently for each of the working side and the driving side. The measuring device detects the left-right difference of the load applied to the tension measuring device, and directly detects or estimates the widthwise passing position of the rolled material at the position of the tension measuring device, and acts on the tension measuring device. It is clear that detecting the thrust force is also an essential requirement.

After the difference between the left and right tensions acting on the rolled material is calculated as described above, the rolling leveling control of each rolling mill is performed with the aim of making the tension difference a predetermined value. At this time, the predetermined target value is generally set to zero as the difference between the left and right sides.
A predetermined target value near zero may be set. Also,
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 rolling leveling control is performed. It is realistic to do it.

Next, a thrust force acting on the tension measuring roll is detected, and rolling reduction control of each rolling mill is performed so that the axial force becomes a predetermined value. In the state where the thrust force is generated as shown in FIG. 4, the main axis 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. First, the tension distribution 1 of the rolled material at the position of the tension measuring roll 1
Even if 1 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 figure. Such a tension imbalance 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 reduction leveling control as described above is simultaneously performed.

The target value of the thrust force acting on the tension measuring roll is basically zero. However, depending on the parallelism error between the tension measuring roll axis and the roll axis of the rolling mill, the target value may be zero. It may be more stable to target a predetermined value in the vicinity. 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 carrying out.

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 provided outside the control loop for setting the left-right difference of the tension acting on the rolled material to a predetermined value. Although it is positioned, the control method may be the reverse of this, or a rolling leveling operation may be performed at a stretch to make the left-right difference in tension and the thrust force simultaneously zero.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A seven-stand tandem mill as shown in FIG. 5 has tension detectors independently on the working side and the driving side between all stands 1a to 1g to detect a vertical load and a roll axial load. Roll 2a for tension measurement
~ 2f, 4 stands 1 continuously from the most downstream rolling mill
Meandering control was carried out using a group of tandem rolling mills in which detectors 3a to 3d capable of measuring the widthwise threading position of the rolled material were provided between stands on the front of the rolling mills of d to 1g.

[0022] Initially, using only the tension measured value of the measuring roll vertical direction load, assuming the material off-center amount is always zero and estimates the tension difference sigma _dfi acting on the rolled material, sigma _dfi
The rolling leveling control was performed with the target of = 0, but the threading condition at the rear end of the rolled material did not reach complete stability.

Therefore, an estimated value of the off-center amount of the material at the position of the tension measuring roll is calculated from the outputs of the rolled material width direction passing-through position measuring devices 3a to 3d, and the estimated value is calculated. The tension difference σ _dfi acting on the rolled material was estimated from the axial load using equation (1), and the rolling leveling control of each rolling mill was performed with σ _dfi = 0 as a target. Further, 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 substantially including the downstream rolling mill was performed. It could be completely stabilized.

[0024]

According to the meandering control method of the present invention, the rolling leveling of each rolling mill in the tandem rolling mill row can be optimized during the steady rolling, and as a result, it is possible to optimize the rolling level at the rear end of the rolled material. As a result, there is almost no accident at the time of threading, and the working rate and the yield can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an algorithm of a meandering control method of the present invention.

FIG. 2 is a schematic diagram 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 for explaining a mechanism in which a load in a roll axial direction is generated on 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-1g Rolling machine 2a-2f Rolled material tension measuring device 3a-3d Width direction threading position measuring device 4 Rolled material 5 Rolling direction 6 Roll axis center position of upstream rolling mill between arbitrary rolling mills 7 Optional rolling mill Roll center position of downstream rolling mill between 8 Roll center positions of tension measuring rolls between arbitrary rolling mills 9 Tension distribution at upstream rolling mill position 10 Tension distribution at downstream rolling mill position 11 Roll position for tension measurement 12 Main axis of tension acting on the rolled material between rolling mills 13 Speed vector of rolled material at the position of roll for tension measurement 14 Peripheral speed vector of roll for tension measurement 15 Speed component in roll axis direction of rolled material

Claims (1)

[Claims] A roll shaft parallel to a roll axis of a rolling mill is provided between two or more rolling mills and at least one rolling mill between the rolling mills, and is rotated in contact with a rolled material. A freely 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. Furthermore, a meandering control 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 the tension measuring roll from a rolled material and a device for measuring a width direction passing position of a rolled material. In the method, from the output of the width direction passing position measuring device, the width direction passing 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 tension measuring roll Vertical force applied From the detected values of the working side and the drive side and the detected value of the force in the roll axis direction acting on the tension measuring roll from the rolled material, the tension truly acting on the rolled material at the position of the tension measuring roll The difference between the working side and the driving side is calculated, and the tension difference falls within a predetermined allowable range, and the force in the roll axis direction applied to the tension measuring roll is also 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 in order to enter the rolling mill.