JPS6324764B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for correcting and controlling meandering of a rolled material rolled by a rolling mill.

[Conventional technology]

Conventionally, plate thickness control in rolling mills has only been controlled so that the average value of the left and right plate thicknesses is constant, and correction of the difference in plate thickness between the left and right sides is currently dependent on manual operation using visual inspection. It is. For this reason, particularly in tandem rolling mills, meandering tends to occur during sheet passing, which causes a reduction in the efficiency of rolling operations.

In response to this, a new method and device for preventing meandering was proposed in Japanese Patent Application Laid-Open No. 52-124453, and an outline of the method will be explained below.

Figure 1b is an equivalent representation of Figure 1a,
K indicates the spring constant on one side of the rolling mill. Since the outlet plate thickness is the sum of the elongation of the rolling mill due to the rolling load and the roll gap under no load, h _w and h _d can be expressed by the following equations.

h _w = S _w + P _w /K ……(1) h _d = S _d + P _d /K ……(2) From equations (1) and (2), the plate thickness difference on the operation side (h _w − h _d )
is, h _w − h _d = (S _{w −} S _d ) + (P _w + P _d )・1/K ... (3) Here, h _w − h _d = Δh _wd , P _{w −} P _d = ΔP _wd , S _w
-S _d = ΔS _wd , Δh _wd = ΔS _wd + ΔP _wd /K ...(4) The difference in roll gap at no load on the operation side and drive side, and the difference in rolling load are detected. This allows us to know the plate thickness difference Δh _wd between the operating side (WS) and the driving side (DS). This equation (4) shows a control method that controls the thickness of the rolled material 5 in the width direction, whereas the conventional gauge meter method controls the thickness of the rolled material 5 in the longitudinal direction. By controlling the roll gap difference ΔS _wd so that ΔS _wd +ΔP _wd /K=0 (5), the plate thickness difference Δh _wd between the operating side and the driving side can be made zero.

Furthermore, like the conventional gauge meter type plate thickness control method, the rolling load signal taken into the control is multiplied by a constant α to obtain ΔS _wd + ΔP _wd /K・α=0...(6) Always use equation (6). If the roll gap ΔS _wd is controlled according to changes in ΔP _wd to satisfy the requirements, the apparent stiffness in the width direction of the rolling mill can be changed by changing the value of α and the amount of ΔP _wd incorporated into the control. be able to. In other words, the apparent Mill constant under control to satisfy equation (6) is
Assuming K _c , at α=0, K _c =K,
As α approaches 1, K _c increases, and when α=1, K _c becomes infinite and Δh _wd =0.

Note that the amount of change in ΔS _wd per unit amount of ΔP _wd changes depending on the magnitude of α. In other words, the larger α is, the larger the amount of change in ΔS _wd is, and when α = 1, it is neither too large nor too small to cancel out the plate thickness difference Δh _wd between the operating side and the drive side, completely canceling it out. This is the optimal amount of change. When α is in the range of 0<α<1, the amount of change in ΔS _wd due to control is insufficient,
A state of insufficient control occurs in which Δh _wd is not completely canceled and remains, and conversely, when α > 1, a state of overcontrol occurs; for example, even if h _w > h _d when not controlled, this is not controlled. Then, h _w < h _d , and h _w
The magnitude relationship between h and _d is reversed.

As explained above, when controlled to satisfy equation (6), Δh _wd =0 at α=1, and α
>1, the plate thickness difference is reversed. Therefore, control is performed in the region of α≧1 to satisfy equation (6), and the rolled material 5
The purpose is to prevent the meandering of the road. In other words, when controlled with α=1, h _w −h _d =0
As can be seen from Fig. 2b, there is no difference ε _L in elongation between the operating side and the driving side, so the rolled material 5
will be held in place wherever it is across the width of the roll, usually in a bitten position. In the case of control with α>1, the result is as follows. For example, if we start the control at α>1 when the rolled material 5 is located at a position deviated from the _center ＞h _d to rolled material 5
Although it is in a position shifted toward the operating side, it is reversed as h _w < h _d . As a result, the elongation rate on the operation side becomes larger than that on the drive side, and a force is generated in the rolled material 5 in the direction of the drive side, forcing it to return toward the center X of the rolling mill. When the center Y of 5 reaches the center X of the rolling mill, ΔP _wd =0 and the rolled material 5 is held in the rolling mill.

FIG. 3 shows an embodiment of Japanese Patent Application Laid-Open No. 52-124453.

In the figure, the difference in thickness Δh _wd between the left and right sides of the rolled material 27 is calculated by the calculation amplifiers 28 to 31 and outputted from the calculation amplifier 31. The output of the thickness difference of the calculation amplifier 31 is input to the hydraulic pressure reduction control devices 12 and 13 in the direction in which the thickness difference Δh _wd becomes zero. The control method shown in FIG. 3 satisfies equation (6), making it possible to prevent meandering. In FIG. 3, the output of the operational widening device 31 is input to the hydraulic reduction devices 12 and 13 in the same magnitude and in opposite directions, so that the upper work roll 25 is symmetrically centered around the center of the rolling mill. Rolled material 2 in a controlled manner
7 so that the thickness in the longitudinal direction does not vary.

The lock-on servo 32 is for correcting the unbalance of the left and right rolling loads caused by the unbalance of the detected values of the rolling loads on the left and right sides, the temperature difference and thickness difference between the left and right sides of the rolled material 27, etc. Then, the relay contact 33 is closed to perform a zero-setting operation so that the output of the operational amplifier 31 becomes zero. The control opens relay contact 33 and closes relay contact 34 when this zero-set operation is completed.
When the relay contact 34 is closed, the meandering prevention control is started. Although the rolled material 27 was caught in the center of the rolling mill, this zero-set operation was carried out to prevent the rolled material 27 from being deviated from the center of the rolling mill in order to control the unbalance between the left and right rolling loads caused by the above-mentioned reasons. This is to correct the fact that erroneous control may be performed due to misidentification.

[Problem that the invention seeks to solve]

The outline of the new meandering prevention method and its device proposed in JP-A-52-124453 has been explained above. When applied to a rolling mill, the bending force for work rolls (hereinafter simply referred to as bending force) to further change the thickness distribution in the width direction of the plate (hereinafter referred to as crown) is applied to the work rolls on the operation side and drive side. When an equal value is applied to the bearing housing for the workpiece (hereinafter referred to as the workpiece chock), an unbalanced load is generally generated on the load cells for detecting the rolling load installed in the housing on the operation side and the drive side, depending on the position of the work roll. In order to detect the load difference ΔP _wd (b) as if the rolled material is meandering even though the rolled material is in the normal position, meandering correction control is activated according to equation (6), and the plate The problem was that it could not maintain its normal position and would meander.

An object of the present invention is to provide a control method and device in which the bending force does not disturb the meandering correction control device in a rolling mill that moves the work roll in the axial direction and applies bending force to the work roll. be.

[Means for solving problems]

The present invention calculates the load difference between the operating side and the driving side by detecting the rolling loads on the operating side and the driving side,
Furthermore, the position of the work roll and the bender pressure are detected, the unbalanced load due to the bender force is calculated, and the unbalanced load is subtracted from the load difference to eliminate the influence of the unbalanced load as a disturbance. .

[Effect]

Here, the mechanism by which the unbalanced load occurs and its value will be explained based on FIG. 4. First, P _w : Detection value of the load cell on the operating side P _d : Detection value of the load cell on the drive side P: Rolling load F: Bender force per 1 chock l: Distance from the center of the mill to the back-up roll bearing box l ₁ : Work roll bearing box 1/2 of the distance between e: Amount of deviation between work roll center and mill center (however,
(assuming that the state in Figure 4 is positive), then the following relationship exists between them due to the balance of force and moment.

Here, F _w = F _d = F, so P _w + P _d = P + 2F...(7) (P _w - P _d )・l=-2・F・e......(8) Equation (7), If (8) is combined to find P _w and P _d , P _w = P/2 + (1-e/l)・F...(9) P _d = P/2+ (1+e/l)・F... …(10) Therefore, the unbalanced load ΔP _wd (b) generated on the load cells on the operation side and drive side due to the bending force is ΔP _wd (b)≡P _w −P _d = −2e/l・F … (11) becomes.

In other words, from the load difference detected by the load cell, ΔP _wd
If the loads on the operating side and the driving side are adjusted so that the value subtracted by (b) becomes zero, meandering will not occur even if a bending force is applied.

〔Example〕

The present invention will be explained below based on an embodiment shown in FIG.

The position e of the work roll is detected by a position detector 35, while the pressure P _F of the bender device 38 is detected by a pressure detector 36. These two signals are then input to the operational amplifier 37, which performs calculation according to equation (11), and is input to the operational amplifier 28 with a negative sign attached. As a result, the output ΔP _wd of the operational amplifier 28 becomes one in which the disturbance to the meandering correction control due to the bending force is removed.

For operations other than those mentioned above, please refer to the above-mentioned Japanese Patent Application Publication No.
Since it is exactly the same as the general explanation of No. 52-124453,
For the sake of brevity, a description thereof will be omitted.

〔Effect of the invention〕

As explained above, according to this embodiment, even in a rolling mill in which work rolls move, the bending force on the operation side and the drive side remain the same, and
It becomes possible to adopt the meandering correction control device No. 124453.

Although not explained in the above embodiment,
To detect the bending force, a load cell that detects the force itself may be used instead of a pressure detector.

The preferred embodiments of the present invention have been described above, but according to the present invention, bending force does not become a disturbance in meandering correction control.

[Brief explanation of the drawing]

Figures 1 a to b are explanatory diagrams showing the behavior of rolled material during meandering, Figures 2 a and b are graphs quantitatively showing the differences in plate thickness, load and elongation, and Figure 3 is a conventional device. FIG. 4 is an explanatory diagram showing the mechanism of disturbance generation due to bender force, and FIG. 5 is a system diagram showing an example of the apparatus of the present invention. 12, 13... Rolling control device, 27... Rolling material, 28, 29, 30, 31, 37... Arithmetic amplifier, 35... Position detector, 36... Pressure detector.

Claims (1)

[Scope of Claims] 1. Operation of a rolling mill equipped with a pair of upper and lower work rolls movable in the axial direction and a roll bending device disposed at the end of the work rolls and applying bending force to the work rolls. By detecting the roll gap difference equivalent to the no-load state and the rolling load difference between the operating side and the driving side, the difference in thickness of the rolled material between the operating side and the driving side is found, and the thickness difference between the operating side and the driving side is determined according to this thickness difference. In the control method for preventing meandering of the rolled material during rolling by controlling the rolling loads on the operating side and the driving side in the direction of reducing the roll gap difference, the amount of movement and bending force of the work rolls are detected, and A meandering correction control method for a rolled material, characterized in that an unbalanced load generated on an operating side and a drive side due to work roll movement and bending force is calculated, and the unbalanced load is subtracted from the rolling load difference. . 2. A rolling mill equipped with a pair of upper and lower work rolls movable in the axial direction, and a roll bending device disposed at the end of the work roll and applying bending force to the work roll, provided on the operation side and the drive side, respectively. a no-load roll gap detector and a rolling load detector; a first calculation amplifier for comparing the no-load roll gap of the operating side and the driving side with respect to the detected values obtained by both the detectors; a second calculation amplifier that calculates the rolling load difference with the driving side; a third calculation amplifier that calculates the thickness difference of the rolled material based on the outputs from the first and second calculation amplifiers; 3. A meandering correction control device comprising two control devices that respectively control the lowering device on the operating side and the drive side using the output of the operational amplifier, a position detector for detecting the amount of work roll movement, and a position detector for detecting the amount of movement of the work roll. a pressure detector that detects bending force;
a fourth calculation amplification device that calculates an unbalanced load generated on the operation side and drive side load cells due to work roll movement and bender force from the signals of the position detector and the pressure detector, the fourth calculation amplification device; A meandering correction control device for a rolled material, characterized in that the unbalanced load is subtracted from the rolling load difference by inputting the output of the device to a second operational amplifier.