JPH07323315A - Method for controlling feedback of plate crown and shape model - Google Patents

Abstract

PURPOSE:To provide a method for controlling feedback by separating the error of the plastic deformation of a plate, which is the largest factor of the predicted error of plate crown and shape in plate rolling, and the error of the change of a roll profile during rolling. CONSTITUTION:A mechanism is made as a method for controlling plate crown and shape in a continuous rolling mill controlling plate profile and plate shape on the outlet side of a last stand to target values by measuring the plate crown of a rolling stock in the outlet side of the last stand, and controlling feedback according to these measured values and calculated values of crowns. And, the error of the measured value of the plate crown in the outlet side of the last stand at a plate edge part to a calculated value, is separated to roll profile error and plastic deformation error. Respective roll profile and plastic deformation model constant are corrected, and the only roll profile error is corrected as a whole error at the non-edge part of a plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feedback control method for a crown / shape model of a rolled material in a continuous rolling mill.

[0002]

2. Description of the Related Art In general, accurate control of the crown and shape of a rolled material such as a steel plate in continuous rolling is important not only for maintaining the quality of the rolled material but also for avoiding troubles during rolling. For this reason, a roll bending device or a variable crown roll is provided in each stand of the continuous rolling mill, and in each stand, the operation amount of these is adjusted to control the crown and shape to target values.

For example, as shown in Japanese Examined Patent Publication No. 5-85245, a feasible roll bending force preset value is calculated to obtain a plate shape control method capable of obtaining an appropriate plate crown and a good plate shape. In order to achieve the target crown and shape based on the predicted rolling force, strip thickness, tension, etc. given by the schedule calculation, satisfy the hardware control of roll bending force and the shape constraint between each stand. Then, the sum of squares of the difference between the final stand target crown and shape and the crown and shape predicted by the mathematical model, the roll bending force preset value to be obtained, and the predetermined bending force. The roll bending force preset value of each stand is obtained by quadratic programming with and as evaluation functions. The have been disclosed.

[0004]

However, in the preset of the plate crown and shape control in this multi-high rolling mill, the accuracy of the prediction model of the plate crown and shape is important, but the maximum error factor in this prediction model is the plasticity of the plate. It is a roll profile change due to deformation and roll wear during rolling and thermal expansion, and there is a problem that it is difficult to control these effects separately from the plate crown and shape error. Therefore, conventionally, all the errors of the plastic deformation of the plate and the change of the roll profile during rolling have been attempted to be corrected by correcting the plastic deformation of the plate and the change of the roll profile during rolling. Therefore, during schedule-free rolling, the error between the two greatly changes from plate to plate, and the error in this feedback method becomes large.

On the other hand, in Japanese Patent Publication No. 5-85245, based on the plate crown model and the plate shape model, hardware control of the plate shape and roll bending force in each stand is used, and the quadratic programming method is used. Therefore, the roll bending force preset value, which is an unknown number, is to be determined, but the operation correction amount of the roll bending force by this method can be used when the rolling conditions such as strip thickness and strip width change. There is a problem that there is no.

[0006]

As a result of intensive studies conducted by the inventors in order to solve the above problems, the present invention has revealed that the plastic deformation of the sheet, which is the largest factor of the sheet crown / shape prediction error in sheet rolling, and The purpose of the invention is to provide a method of separating feedback error of roll profile change during rolling and performing feedback control. In the plate crown / shape control method for a continuous rolling mill, which controls the plate crown / shape on the final stand exit side to the target value by feedback control based on the calculated value and the mechanical crown calculated value, the plate on the final stand exit side at the plate edge part The error of the measured crown value from the calculated value is separated into roll profile error and plastic deformation error, and each roll profile error is calculated. Together to correct Lumpur and plastic deformation model constants, the plate non-edge portion in the feedback control process of strip crown and shape model, characterized in that to correct only the roll profile errors as total error.

[0007]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a system configuration diagram for explaining an embodiment according to the present invention. In FIG. 1, a hot rolling mill group 1
Is a continuous rolling mill for steel plates having 6 stands with quadruple rolls, and the rolling material 2 is composed of a work roll 3 to be directly rolled, and a backup roll 4 which contacts the work roll 3 and reinforces it. The work roll 3 is controlled by the controller 5 in the amount of reduction. Reference numeral 6 denotes an arithmetic unit of the control unit 5, which is a roll profile predicting unit 7
The shape change coefficient of the stand is calculated by the control amount calculation unit 10 from the rolling condition data of the plate deformation prediction unit 8 and the like, and the shape change coefficient is compared with the set index value. On the other hand, a crown detector 9 is provided on the exit side of the final stand, and a detection signal from this detector is input to the arithmetic unit 6 to perform arithmetic correction.

FIG. 2 is an explanatory view showing the plate crown error in the plate width direction according to the present invention. As shown in FIG. 2, the plate edge portion is three-dimensionally deformed, which causes a large plastic deformation error. Therefore, the plate crown error (actual result and calculation) is separated into a roll profile error (edge base point error) and a plastic deformation error (plate crown error and roll profile error), and each roll profile and plastic deformation model constant are corrected. On the other hand, in the non-edge portion of the plate, the change in the plastic deformation error of the plate is considered to be small, and all are treated as roll profile errors. That is, the feedback is also performed only on the roll profile error.

Therefore, the roll profile error ΔC _R in the non-edge portion corrects the roll profile as _{ΔC R} = C _aq -C _cal . However, C _aq : Actual value of crown C _cal : Calculated value of crown Also, roll profile error ΔC _{RP at the} edge part
Corrects the roll profile as _{ΔC RP} = (C _aq −C _cal ) × (width direction correction value).

Furthermore, the plastic deformation error △ C ^P _{R ^{is, △ C P R.New = C aq}} - △ C R △ C P R = α · △ C P R.New + (1-α) △ C P R _.Old However, △ C ^P _R.New: modify plastic deformation error △ C ^P _R.Old: modifying the plastic deformation model constants as before modification plastic deformation error. In this way, the error for the calculated value of the plate crown actual value on the exit side of the final stand at the plate edge part is separated into the roll profile error and the deformation error, and each roll profile corrects the plastic deformation model constant and the non-edge part. Then, only the roll profile error is corrected as the total error.

[0011]

As described above, according to the present invention, it is divided into a plate edge portion and a non-edge portion, and at the plate edge portion, the roll during rolling due to the plastic deformation error of the plate and the wear and thermal expansion of the roll. After the profile error is separated, each roll profile and plastic deformation model constant are modified, while the plate non-edge part uses the control method that modifies only the roll profile error. Can be reduced, the plate crown and shape control accuracy over the entire length of the rolled material can be greatly improved, and strips with good plate crown and shape quality can be manufactured.
It has an extremely excellent effect of improving the yield.

[Brief description of drawings]

FIG. 1 is a system configuration diagram for explaining an embodiment according to the present invention.

FIG. 2 is an explanatory diagram showing a plate crown error in a plate width direction according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hot rolling mill group 2 Rolled material 3 Work roll 4 Backup roll 5 Control device 6 Calculation device 7 Roll prophy prediction unit 8 Plate deformation prediction unit 9 Crown detector 10 Control amount calculation unit

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B21B 38/02 8315-4E B21B 37/00 116 M 37/12 BBM

Claims (1)

[Claims] 1. Continuous rolling in which the strip crown of the rolled material is measured on the exit side of the final stand, and the strip crown / shape on the exit side of the final stand is controlled to a target value by feedback control based on these measured values and crown calculation values. In the plate crown / shape control method of the machine, the error of the measured value of the plate crown at the exit side of the final stand at the plate edge is separated into roll profile error and plastic deformation error, and the roll profile and plastic deformation model constants are separated. In addition to the above, the feedback control method of the plate crown / shape model is characterized by correcting only the roll profile error as the total error in the plate non-edge portion.