JPS63303611A - Method and apparatus for controlling shape of rolled stock - Google Patents

Abstract

PURPOSE:To improve shape control ability and correcting accuracy by shape controlling at an upstream stand by a signal having a larger time constant of time variation among shape detecting signals of the width direction of a rolled stock at the final stand of a tandem rolling mill. CONSTITUTION:The shape signal from a shape detector 16 disposed on an outlet side of the tandem rolling mill is transduced to a physical quantity to express a steepness or a difference of elongation percentage, etc., by a shape signal processor 1, then inputted into a shape parameter transducer 2. The shape parameter is outputted as a feedback so that a number of the detected values which are inputted are made recognizable as a shape distribution pattern suited to use for controlling. At a pending, a deflection between the feed back value and a target value of an target shape setting device 3 is inputted, and a pending force as a manipulated variable required for the shape correction is obtained to output to pending driving device 5. Based on a signal for manipulated variable the work roll pending device of a 3rd stand is driven to correct the shape of the rolled stock.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method and apparatus for controlling the shape of rolled material.

[Conventional technology]

In equipment for rolling strip-shaped materials such as steel plates, the shape of the rolled product is an important factor in terms of its quality and yield. Here, the shape of the rolled material indicates the flatness of the plate, and defects in shape include Figs.
As exemplified in c), there are one-sided elongation, edge elongation, and medium elongation. It is known that these shape defects are caused by non-uniform elongation in the width direction of the sheet during rolling. For example, steepness λ and elongation E1 are known as quantitative expressions of these shape defects. As shown in FIG. 3, the steepness λ is expressed by the following equation (1), where Q is the pitch of the corrugations of the rolled material 12 and δ is the height of the corrugations.

λ=δ/Q×100[%] ・(1) On the other hand, for the elongation rate ε wing, let QO be the actual length of the plate corresponding to the pitch Q (length measured along the wave), and the following Formula (2)
It is represented by

ε dew=(no-Q)/Q...(2
) Furthermore, it is known that the relationship between the steepness λ and the elongation rate E is expressed by the following equation (3).

E, = (πλ/200)” ... (3
) The above-mentioned uneven elongation of the rolled material occurs because the gap between the upper and lower rolling rolls is not uniform in the width direction of the sheet. The causes include non-uniform thickness distribution of the rolled material, deflection of the rolling rolls, thermal expansion of the rolling rolls, and the like.

As a control method to correct such shape defects.

Methods using leveling of a rolling down device or work roll bending in which work rolls are bent in the width direction of the sheet are known. In addition to the above-mentioned methods for six-high rolling mills having intermediate rolls, methods such as intermediate roll bending or intermediate roll shifting in which the intermediate roll is moved in the width direction of the sheet are known (Japanese Patent Laid-Open No. 54-151066, Japanese Patent Laid-Open No. 151066, 55-
42144, Japanese Unexamined Patent Publication No. 55-42164). In these control shift systems, a shape detector is installed on the exit side of the rolling mill, and based on the shape data detected by the shape detector, the shape control end of the bending device, etc. on the rolling mill immediately before the shape detector is adjusted. It is configured as a closed-loop system that drives and corrects the shape of the rolled material.

In order to detect shape defects in a rolled material, for example, as shown in Japanese Patent Laid-Open No. 54-151066, the shape distribution in the width direction of the strip is detected using several dozen shape sensors arranged in the width direction of the strip. This shape distribution is expressed by n shape parameters that are pattern-recognized in correspondence with the number n of shape operation terminals that can be operated independently. In other words,
In a rolling mill having four types of shape operation ends, four shape parameters are defined from the shape detection signal.

Here, the shape parameter Ci and the shape operation end F.

For example, if a model expressing the relationship between The shape of the rolled material is modified by determining a manipulated variable signal ΔF+ for modifying the shape of the rolled material, and driving the shape operating end of the rolling mill based on this. In addition, α1. is the influence coefficient.

[Problem that the invention seeks to solve]

By the way, in the above equation (4), if the shape parameter CI is the elongation rate ε at a certain point in the board width direction, and the manipulated variable signal F is the pending force (tons), then the influence coefficient α is approximately 5 x 10-4. . Since the heat crown changes by about 80 μm depending on the rolling conditions, when these are transferred to a thick rolled material with a plate thickness of 0.41, the elongation rate ε is calculated by the following formula (
As shown in 5), it becomes 0.2. In addition, H is the reduction amount, Δ
H indicates the amount of change.

If we attempt to correct this difference in elongation rate of 0.2 using the pending force, the difference will be approximately 400 tons. Since the maximum value of the pending force at the normal shape control end is about 200 tons, there is a problem that it exceeds the control capability of the conventional shape control system.

In other words, according to the conventional shape control device using a single rolling mill, there is a power limit to the shape correction ability, and when the shape deterioration factors such as the thickness distribution of the rolled material or the thermal expansion of the rolling rolls are large, the rolling There was a problem that the shape of the material could not be modified sufficiently.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, in other words to provide a shape control end device for individual rolling mills.

[Means for Solving the Problems] In order to achieve the above object, the control method of the present invention detects the shape of the rolled material in the width direction of the rolled material on the exit side of the final stand of the tandem rolling mill, and detects the shape of the rolled material in the width direction of the rolled material based on this. The shape control end of the final stand is driven to correct the shape of the rolled material, and the shape control end of the upstream stand is driven based on a shape detection signal with a large time constant of time change among the shape detection signals. It is characterized by modifying the shape of the rolled material.

Further, the control device of the present invention that directly implements the above control method includes a shape detector arranged on the exit side of the final stand of the tandem rolling mill to detect the shape distribution of the rolled material in the width direction, and an output from this detector. a manipulated variable calculation device that calculates a manipulated variable signal of a shape operating end in order to make the shape detection signal detected coincide with its target value; and a shape operating end drive device that drives the shape manipulated end of the final stand based on this manipulated variable signal. and a shape operation end drive device that drives the shape operation end of the upstream stand based on the operation amount signal with a large time constant obtained by passing the operation amount signal through a reduced pass filter. .

[Effect]

Because of this configuration, among the shape modification capabilities required of the final stand, the modification function for those with large change cycles such as those caused by heat crown, that is, those that change slowly, can be performed by the shape manipulation of the upstream stand. Since the power is distributed to the ends, the shape modification ability (power) as a whole is improved. This expands the shape modification limit and improves accuracy.

〔Example〕

Hereinafter, the present invention will be explained based on examples.

FIG. 1 shows an overall configuration diagram including a shape control device according to an embodiment of the present invention. This embodiment shows the present invention applied to a three-tandem rolling mill, and the inlet side of the tandem rolling mill is Rolled material 1 unwound from the installed payoff reel 10
2 is connected to the first stand 13 via the deflector roll 11
．． Second stand 14. It is rolled by the third stand 15, passes through a shape detector 16 which also serves as a deflector roll, and is wound onto a tension reel 17. Next, the shape control device will be explained.

The shape detection signal from the shape detector 16 disposed on the exit side of the tandem rolling mill is processed by the shape signal processing device 1 to determine the steepness λ.
and the elongation rate E, and are converted into physical quantities representing the shape, and input to the shape parameter conversion device 2. here,
The number of measurement points in the width direction of the rolled material 12 is approximately 40 points.

The shape parameter conversion device 2 recognizes a large number of input detected values as a shape distribution pattern suitable for use in control. That is, since the shape operation end used for shape modification has different correction ability depending on the position in the width direction, a pattern corresponding to the shape operation end provided in the rolling mill is recognized, and the shape parameter Cr expressed in this pattern is
n is output as a λ-dpuck.

The bending force calculation device 4 inputs the deviation between the shape parameter feedback value CFB and the shape parameter target value CR set by the target shape setting table [3,
4) Based on the shape model of equation 4, the pending force as the operation amount necessary for shape correction is determined and outputted to the bending drive device 5 as the operation amount signal for shape correction.

The bending drive device i5 drives the work roll bending device of the third stand based on the input operation amount signal to correct the shape of the rolled material.

Up to this point, this is the same as the shape control device disclosed in the above-mentioned publication.

Next, the characteristic parts according to the present invention will be explained.

The filter 6 is a low-pass filter that receives the operation amount signal of the closed-loop shape control in the final stand 15, and
The cutoff frequency is selected based on the time constant of the rolling thermal crown of the third stand 15, but does not have to be a dense value.

The manipulated variable signal that has passed through the filter 6 is compared with a reference bending value output from a reference bending setting device 7, and the deviation thereof is input to the bending drive device 9 through an integral (I) compensator 8. The above standard bending value is set so that the bending device of the Na2 stand can be controlled stably.For example, when the pending force is close to zero, there is a tendency for play to occur in control, so it is important to check whether there is play at the shape operation end, etc. Settings are adjusted based on. - Also, the integral time constant τ of the integral compensator 8 is determined to be larger than the dead time T until the bending change of the &2 stand is measured by the shape detector 16.

The operation of the embodiment configured as described above will be explained with reference to the signal waveform diagram of each part shown in FIG. 4. Note that FIG. 4 explains the shape correction operation by taking as an example a rolling phenomenon in which a heat crown occurs.

FIG. 4(a) shows the change in shape over time in a state where no shape control is performed.

Further, the vertical axis indicates the shape parameter C, and the horizontal axis indicates the time t. The changes in the shape parameters shown in Figure (a) indicate that the shape of the rolled material has a tendency of medium elongation.
Such medium elongation occurs when the thermal crown of the roll becomes large. Examples of cases in which the thermal crown of a roll increases include rolling immediately after the rolls are rearranged, or when the width of the rolled material changes from narrow to wide. Note that the larger the shape parameter becomes positive, the larger the medium elongation becomes. Further, in the case of a rolled material in which the crown of the base material gradually becomes larger, the same tendency as described above occurs. Figures 4 (b) and (Q) show changes when shape control is performed using the conventional method, and Figure 4 (Q) shows changes over time in the pending force at the final stand.
b) shows the change in shape parameters after correction. It can be seen that elongation occurs in these cases. Also, the same figure (b
), when the sign of the pending force changes from positive to negative or from negative to positive, the shape of the rolled material changes unstably due to the nonlinear characteristics of the operating end.

On the other hand, the shape parameters according to the embodiment in FIG.
Figures (d) to (f) show the temporal changes in the stand pending force and the second stand pending force.
As can be seen from d) to (f), the shape correction of the second stand serves to correct the slow change in shape defects, and also biases the reference value of the shape correction operation of the third stand. In order to fulfill the role of giving, the pending force of the third stand does not switch between positive and negative, making it possible to avoid a non-linear region.

Although the second stand pending force is saturated at tz shown in FIG. It can be seen that it is spreading.

As described above, according to this embodiment, among the operation amount signals based on the shape detection signal, those with a large time constant, that is, those with a large shape change period, are modified in shape by the shape operation end attached to the upstream stand. This reduces the shape modification ability required for the final stand.
This has the effect of increasing the shape correction ability as a whole, expanding the shape correction range and improving accuracy. Therefore, it is possible to sufficiently modify the shape of rolled material when the thickness distribution of the rolled material is large or when the thermal expansion of the rolling roll is large, which conventionally had limitations in terms of power.

In addition, since the shape correction operation applied to the stand plays the role of biasing the shape correction operation of the final stand, it is possible to avoid the change of positive and negative of the pending force of the final stand and avoid the correction operation in the nonlinear region. This has the effect of further improving the accuracy of shape correction.

In the embodiment shown in FIG. 1, the integral compensator 8 is provided to compensate for the bending operation, but the integral compensator 8 is not necessarily required.
Needless to say, it is not necessary to use a compensator that includes an integral function.

In addition, in the embodiment shown in FIG. 1, a shape control device was explained that uses the shape control end connected to the last stand and the stand one upstream side thereof, but by incorporating a further upstream rolling stand, the load distribution can be improved. If you proceed, you can further expand the shape correction range.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to improve shape correction ability and correction accuracy.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is an overall block configuration diagram of an embodiment of the device to which the present invention is applied, FIGS. 2(a) to (c) are diagrams showing examples of shape defects, and FIG. 3 4 is a side view for explaining the quantitative expression of shape defects, and FIG. 4 is a signal waveform diagram of each part for explaining the operation of the embodiment shown in FIG. DESCRIPTION OF SYMBOLS 1... Shape signal processing device, 2... Shape parameter conversion device, 3... Target shape setting device, 4... Bending calculation device, 5... Bending drive device, 6...
・Filter, 7...Reference bending setting device, 8.
... Integral compensator, 9... Bending drive device, 13
, 14° 15... Rolling stand, 16... Shape detector.

Claims (1)

[Claims] 1. The shape of the rolled material in the width direction of the rolled material is detected on the exit side of the final stand of the tandem rolling mill, and based on this, the shape control end of the final stand is driven to correct the shape of the rolled material. At the same time, the shape control of the rolled material is characterized in that the shape control end of the upstream stand is driven to correct the shape of the rolled material based on the shape detection signal having a large time constant of time change among the shape detection signals. Method. 2. Located on the exit side of the final stand of the tandem rolling mill,
a shape detector that detects the shape distribution in the width direction of the rolled material; a manipulated variable calculation device that calculates a manipulated variable signal of a shape operating end in order to match the shape detection signal output from the detector with its target value; A shape operation end drive device that drives the shape operation end of the final stand based on this manipulated variable signal, and a shape operation end drive device that drives the shape operation end of the final stand based on the manipulated variable signal with a large time constant obtained by passing the manipulated variable signal through a low-pass filter. A shape control device for a rolled material, comprising: a shape control end drive device for driving a shape control end of a stand;