JPH05317942A - Method and device for controlling plate thickness in rolling mill - Google Patents

Abstract

PURPOSE:To prevent the fluctuation of plate thickness caused by the eccentricity of each of upper and lower backup rolls by adding a quantity of correction of a roll gap to cancel the eccentric quantity of a backup roll to the quantity of correction of the roll gap from a plate thickness controller. CONSTITUTION:A detecting device 7 of roll eccentricity stores an amount of displacement of a roll gap when a roll gap is adjusted so that a rolling load takes a prescribed value in accor dance with rotation angle of of each of upper and lower backup rolls. An eccentric quantity of one of upper and lower backup rolls is subtracted from the stored value, an eccentric quantity of the other unknown roll is calculated, which is stored according to the rotation angle of each of the upper and lower backup rolls. A roll eccentricity detecting device 7 is connected to an eccentric correcting device 8 via a signal. A roll gap correction quantity canceling the eccentric quantity of each roll corresponding to the rotation angle of each of the upper lower backup rolls 2a, 2b is added by the device 8 to the correcting quantity of the roll gap as an output signal from a plate thickness correcting device 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling mill sheet thickness control method and apparatus for preventing a variation in sheet thickness due to eccentricity of upper and lower backup rolls in the rolling mill.

[0002]

2. Description of the Related Art In hot rolling and cold rolling, a so-called quadruple rolling mill in which a set of work rolls and a set of backup rolls are combined is often used. However, in such a rolling mill that also uses a backup roll, eccentricity of the backup roll causes a plate thickness fluctuation in a constant period in the plate longitudinal direction, and this plate thickness fluctuation is prevented by a conventional gauge meter AGC. I can't.

That is, pressure such as hot rolling and cold rolling is applied.
In rolling work, gauges are used
Meter AGC is widely used, but this control
As is well known, the plate thickness deviation Δh shown in equation (1) becomes zero.
Since it controls the rolling reduction position S, Δh = ΔS + ΔP / M (1) ΔS = S-SL (2) ΔP = P-PL (3) Δh: Thickness deviation S: Rolling position SL: Lock
Rolling position when turned on M: Mill rigidity coefficient P: Rolling load PL: Lock
Rolling load when on According to this, the fluctuation of the rolling load P, that is, the skid
The plate thickness deviation Δh due to the characteristic changes of rolled materials such as marks is
Although it will be resolved, the
Thickness deviation due to eccentricity of roll is not taken into consideration
Therefore, it is said that plate thickness fluctuation will occur due to eccentricity of the roll.
There was a drawback.

Moreover, the combined eccentricity of the upper and lower backup rolls varies with the change in the relative rotational angle phase of the upper and lower backup rolls when the diameters of the upper and lower backup rolls are different or when there is a load disturbance on the rolling mill. Since it changes, it is necessary to be able to control the plate thickness by following the changing phase angle.

Therefore, according to the plate thickness control method disclosed in Japanese Patent Publication No. 3-62484, in a rolling mill in which upper and lower backup rolls are provided with a circumferential length difference, the load fluctuation amount in the kiss roll state is determined by the upper and lower backup rolls. The phase angle is measured for one cycle of 360 °, and the measured load fluctuation amount is divided by the mill rigidity coefficient to convert into the combined eccentricity amount of the upper and lower backup rolls. For a cycle of 360 °, the rotation phase angle of the roll and one of the upper and lower reference backup rolls are stored in correspondence, and the rolling phase angle of the roll and the reference backup roll rotation angle are continuously stored during rolling. That is, the sheet thickness control signal is corrected based on the stored combined eccentricity amount corresponding to the detected rotation phase angle and the reference roll rotation angle. By, the eccentricity of the upper and lower backup rolls, are with to prevent caused by thickness variation.

Further, according to the eccentricity detection method disclosed in Japanese Patent Laid-Open No. 59-150612, the rolling load of the upper and lower backup rolls at a constant rotation angle or at a constant time during the rotation of the rolling roll, and the upper and lower rolls. The rotation angle of the lower backup roll is detected and stored, and the storage value of the rolling load from a certain rotation angle and the storage value of the rolling load from an angle obtained by rotating one rotation of the upper and lower backup rolls from that rotation angle are stored. The eccentricity amounts of the upper and lower backup rolls are detected separately by calculating the difference between

[0007]

[Problems to be Solved by the Invention]
In the former conventional technique disclosed in Japanese Patent No. 62484, when the difference in diameter between the upper and lower backup rolls is small, for example, it is 1
In the case of%, the roll must be rotated 100 times in order to store the combined eccentricity amount of the backup roll, which requires a long time for storage.

Further, in the latter prior art disclosed in Japanese Patent Laid-Open No. 59-150612, the back-up roll eccentricity amount of one of the upper and lower rolls is changed to the other one without intervening an amount corresponding to the above-mentioned composite eccentricity amount. Since the backup roll eccentricity amount component is directly removed, there is a drawback that the convergence is not guaranteed against noise. In addition, all of these conventional techniques
Since it is a method of detecting the roll eccentricity using the rolling load, it is affected by the mill rigidity.

The present invention solves all of these problems of the prior art, and determines the roll eccentricity of each of the upper and lower backup rolls in a short time based on the roll gap displacement under a constant load. By controlling the roll gap to eliminate the roll eccentricity of the rolls, the influence of the roll eccentricity of the backup roll can be almost completely removed. And a device.

[0010]

According to the plate thickness control method for a rolling mill of the present invention, the roll gap is adjusted so that the rolling load has a predetermined value during the roll rotation in the kiss roll state prior to rolling. At the same time, the roll eccentricity of the upper and lower backup rolls is detected based on the roll gap displacement during the adjustment, and the roll gap correction amount that cancels the eccentricity of the backup rolls during rolling is controlled by the plate thickness control. It is added to the roll gap correction amount from the device.

More preferably, the roll is rotated in the kiss roll state, and the rolling load is based on the roll eccentricity and the roll gap displacement at the rotation angles of the upper and lower backup rolls at the time when the roll eccentricity detection is started. The roll gap displacement amount when the roll gap is adjusted to be a predetermined value is stored according to the rotation angle of each of the upper and lower backup rolls, and the eccentric amount of one of the upper and lower backup rolls is stored from the stored value. Is subtracted to obtain the roll eccentricity of the other backup roll, and during the rolling operation, the roll eccentricities corresponding to the rotation angles of the upper and lower backup rolls are removed to adjust the roll gap.

The strip thickness control device for a rolling mill according to the present invention comprises a rolling load detector, a roll gap adjuster, and respective rotation angle detectors for detecting the rotation angles of the upper and lower backup rolls. During roll rotation in the kiss roll state, the rolling load controller that adjusts the roll gap so that the rolling load becomes a predetermined value, and under the predetermined rolling load, based on the time when the eccentricity detection of the backup roll is started. , Roll gap displacement,
The roll eccentricity detection device stores the roll eccentricity according to the rotation angle of each of the upper and lower backup rolls, and calculates and stores each roll eccentricity amount of the upper and lower backup rolls based on the stored value. At this time, the roll eccentricity is adjusted by adding the roll gap correction amount that cancels each roll eccentricity amount corresponding to the rotation angle of each upper and lower backup roll to the roll gap correction amount from the plate thickness correction device. And a correction device.

[0013]

According to the plate thickness control method of the present invention, the roll eccentricity amount according to the rotation angle of each of the upper and lower backup rolls can be accurately determined in a short time from the roll gap displacement amount under a constant load condition. You can ask.

Since the other roll eccentricity is indirectly obtained from the roll gap displacement corresponding to the combined eccentricity of the backup roll, the roll eccentricity can be converged to noise. Can be fully assured. Moreover, in this method, the roll eccentricity of each of the upper and lower backup rolls is detected based on the displacement of the roll gap when the rolling load is maintained at a predetermined value. Can be effectively removed. Then, in the rolling work, the roll gap is adjusted by adding the roll gap correction amount for canceling each roll eccentricity amount corresponding to the rotation angle of each of the upper and lower backup rolls to the roll gap correction amount from the plate thickness control device. By doing so, it is possible to very effectively prevent the plate thickness variation due to the eccentricity of the backup roll.

Further, in the plate thickness control device of the present invention, during constant load rotation in the kiss roll state, the roll eccentricity detection device detects the roll eccentricity amount of each of the upper and lower backup rolls from the roll gap displacement amount detected in advance. By calculating and storing, the roll eccentricity according to the rotation angle of each backup roll can be accurately obtained in a short time, and the influence of noise and mill rigidity can be obtained from the roll eccentricity. Can be effectively removed. And
During rolling, by adjusting the roll gap based on the obtained roll eccentricity amount, the roll eccentricity compensating device is operated, so that the plate thickness variation caused by the eccentricity of the upper and lower backup rolls can be sufficiently adjusted. It is possible to perform the highly accurate plate thickness control that is prevented.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating a plate thickness control device of the present invention. In the figure, 1a and 1b are a pair of work rolls paired up and down, and 2a and 2b are also paired up and down. 3 shows a roll load detector, and 4 shows a roll gap adjuster. Further, 5a and 5b in the figure are backup rolls 2a and
2 shows the respective rotation angle detectors for 2b, 6 shows a rolling load controller that keeps the rolling load constant according to the set rolling load target value, and 7 shows a roll eccentricity detection device.

Here, each rotation angle detector 5a, 5b functions to detect the rotation angle from the reference position of each backup roll 2a, 2b, for example, the position at the time when the eccentricity detection of the roll is disclosed. The rolling load controller 6 keeps the rolling load detected by the rolling load detector 3 at a constant target value under the kiss-roll condition so that the roll gap adjuster 4 can keep the rolling load constant.
To adjust the roll gap. Then, the roll eccentricity detection device 7 calculates the roll gap displacement amount when the roll gap is adjusted so that the rolling load has a predetermined value under the kiss roll state as shown in the drawings, by the rotation angles of the upper and lower backup rolls. The roll eccentricity of one of the upper and lower backup rolls is subtracted from the stored value to calculate the unknown roll eccentricity of the other roll, and the roll eccentricity of each of them is calculated. Also functions to store according to the rotation angles of the upper and lower backup rolls.

The roll eccentricity detection device 7 is signal-connected to a roll eccentricity correction device 8 here, and the roll eccentricity correction device 8 outputs an output signal from the plate thickness correction device 9 in an actual rolling operation. The roll gap correction amount for canceling the roll eccentric amounts corresponding to the rotation angles of the upper and lower backup rolls 2a and 2b is added to the roll gap correction amount.

Therefore, by inputting the roll gap correction signal after finishing such calculation to the roll gap adjuster 4 through the signal switcher 10, the roll gap adjuster 4 is made to be the backup rolls 2a, 2b. The roll gap can be adjusted without being affected by the eccentricity of the rolls, and the plate thickness variation due to the roll eccentricity of those rolls can be effectively prevented.

The signal switch 10 here is
When detecting the amount of roll eccentricity of the backup rolls 2a, 2b, a signal connection between the rolling load controller 6 and the roll gap adjuster 4 is provided, and during rolling work, the roll eccentricity correction device 8 and the roll gap adjuster 4 are connected. Bring the connection of.

Next, the operation of the device of the present invention will be described with reference to FIGS.
Will be explained. FIG. 2 shows a two-dimensional array R (i, j) in which the upper backup roll angle is a column and the lower backup roll angle is a row. The loci of the upper and lower backup roll angles due to the rotation of the roll are shown as the upper backup roll angle. It is shown in sync with. In the figure, ● indicates the first rotation of the upper backup roll 2a, and ○ indicates the second rotation thereof. In the figure, the vertical and horizontal axes are divided into N, but the number of divisions can be arbitrarily selected.

With reference to the time when the roll eccentricity detection is started,
The roll gap displacement amount under the control of constant rolling load in the kiss roll state is substituted into the corresponding position of the two-dimensional array in accordance with the rotation of the upper and lower backup rolls. For example, noise can be removed by averaging data having the same combination of upper and lower backup roll angles.

The roll eccentricity storage unit has two one-dimensional arrays X and Y corresponding to the numbers of rows and columns of the above-mentioned two-dimensional array. Regarding the two-dimensional array R that stores the roll gap displacement amount from the start point of roll eccentricity estimation, of R (i, j) and R (i + 1, j) (j = 1 to N), both are up and down. For the element rows R (i, k) and R (i + 1, k) on the backup roll locus, the following equation (4);

[Equation 1] By calculating, the roll eccentricity difference T (i) at the angle step i + 1 of the lower backup roll and i can be obtained. Therefore, the eccentricity of the lower backup roll can be calculated by the following formula (5);

[Equation 2] Required by. Further, the upper backup roll eccentricity is calculated by using the element sequence R (l, j) located on the above locus among R (i, j) {i = 1 to N} and the following expression (6);

[Equation 3] Can be obtained by In this example, the lower backup roll is used for calculation, but the upper backup roll may be used for calculation.

FIG. 3 is a flow chart showing this. After obtaining the roll eccentricity amounts according to the rotation angles of the upper and lower backup rolls in accordance with this flow chart, the rolls are actually rolled. By correcting the roll gap correction amount with the correction amount corresponding to the eccentricity amount, it is possible to sufficiently eliminate the plate thickness variation caused by the roll eccentricity.

As described above, according to this method, it is not necessary to store data until the phase difference of the upper and lower backup rolls reaches 360 °, and even if the phase difference is small, the roll eccentricity can be efficiently determined. It turns out that detection is possible.

Thus, in the present invention, the amount of eccentricity of each of the upper and lower backup rolls 2a and 2b is detected based on the amount of roll gap displacement during constant load rotation in the kiss roll state.
The roll eccentricity amount according to the rotation angle of each of the upper and lower backup rolls can be accurately obtained in a short time. Moreover,
The amount of roll eccentricity can be sufficiently converged with respect to noise, and the influence of mill rigidity on the amount of roll eccentricity can be effectively removed.

FIG. 4 shows the test results of the method of the present invention when the eccentricity of the upper and lower backup rolls 2a and 2b is given by the same amount of sine wave and the roll rotation speed is changed by 1%. According to the graphs shown in the drawings, the amount of eccentricity of each of the upper and lower backup rolls is accurately detected in each test.

[0028]

As is apparent from the above description, according to the present invention, even when the rotation speeds of the upper and lower backup rolls are different, the roll eccentric amounts of the upper and lower backup rolls can be accurately separated in a short time. Therefore, it is possible to realize high plate thickness accuracy.
In addition, since the roll eccentricity is detected by using the physical quantity, which is the same dimension as the roll eccentricity, called the roll gap displacement, it is possible to detect the roll eccentricity and to control the plate thickness without being affected by the rolling load. is there.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a plate thickness control device of the present invention.

FIG. 2 is a diagram showing an example of a roll eccentricity amount detection work procedure in the present invention.

FIG. 3 is a diagram showing an example of a work procedure of the present invention.

FIG. 4 is a diagram illustrating a detection result of a roll eccentricity amount.

[Explanation of symbols]

 1a, 1b Work roll 2a, 2b Backup roll 3 Rolling load detector 4 Roll gap adjuster 5a, 5b Rotation angle detector 6 Rolling load controller 7 Roll eccentricity detector 8 Roll eccentricity compensator 9 Plate thickness corrector 10 Signal Switch

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Shiomi 1-chome, Mizushima Kawasaki-dori, Kurashiki City, Okayama Prefecture (no address) Inside Mizushima Works, Kawasaki Steel Co., Ltd. (72) Akira Urano Mizushima Kawasaki, Kurashiki City, Okayama Prefecture Dori 1 chome (no street number) Kawasaki Steel Co., Ltd. Mizushima Steel Works (72) Inventor Noboru Ozawa 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Kawasaki Steel Co., Ltd. Chiba Steel Works

Claims (2)

[Claims] 1. The roll is rotated in a kiss roll state so that the rolling load becomes a predetermined value based on the roll gap displacement amount at the rotation angle of each of the upper and lower backup rolls at the time when the roll eccentricity detection is started. The amount of roll gap displacement when the gap is adjusted is stored according to the rotation angle of each of the upper and lower backup rolls, and the roll eccentricity of each of the upper and lower backup rolls is calculated from the stored value. The method for controlling the plate thickness of a rolling mill is characterized by removing the roll eccentricity amount corresponding to the rotation angle of the roll and adjusting the roll gap. 2. A rolling load detector, a roll gap adjuster, and respective rotation angle detectors for detecting the rotation angles of the upper and lower backup rolls are provided, and the rolling load is predetermined when the roll is rotating in the kiss roll state. Rolling load controller that adjusts the roll gap to the value of, and the amount of roll gap displacement of the upper and lower backup rolls based on the time when the eccentricity detection of the backup roll is started under a predetermined rolling load. The roll eccentricity detection device stores the roll eccentricity according to the rotation angle and calculates and stores the roll eccentricity of each of the upper and lower backup rolls based on the stored value. For the roll gap correction amount from the correction device, the roll eccentric amount corresponding to the rotation angle of each of the upper and lower backup rolls is canceled. Rugyappu correction amount by adding the rolling mill of plate thickness control apparatus characterized by comprising a roll eccentricity compensation system for adjusting the roll gap amounts.