JPH07251213A - Method for controlling crown/shape in rolling mill - Google Patents

Abstract

PURPOSE:To prevent the deterioration of flatness and to improve the accuracy of crown by measuring crowns on the inlet and outlet sides of a specified stand, calculating the flatness on the outlet side of the stand and operating a crown control actuator. CONSTITUTION:Crown measuring devices 4, 5 are provided on the inlet and outlet sides of a 5th stand and the crown and thickness of a material 10 to be rolled on the inlet and outlet sides of the 5th stand are continuously measured. In a flatness arithmetic unit 8 on the outlet side of the 5th stand, the elongation-percentage difference on the outlet side of the 5th stand is calculated using these measured values and the coefficient of shape change set with the control computer 9 and outputted to a 5th stand controller 7. In the controller 7, the changing amount of the bender force of a 5th stand is calculated, outputted to a controller 6 and the bender force of the 5th stand is changed. Further, in the controller 7, flatness is monitored and calculation is interrupted when the flatness reaches the boundary value of the allowable range. The allowable range of flatness used at this time is set to the controller 7 by retrieving the table which is classified by thickness, width and kinds of steel with the control computer 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crown / shape control method for a rolling mill for rolling a metal strip.

[0002]

2. Description of the Related Art Demands for improving dimensional accuracy in hot coils and the like have become increasingly severe in recent years. For dimensional accuracy,
In addition to the uniformity of the plate thickness and the plate width in the rolled material longitudinal direction, it is desired that the crown, which is the plate thickness distribution in the rolled material width direction, has a predetermined value. Corresponding to this, a crown measuring device is installed on the rolling mill exit side, centering on the finish rolling mill of the hot strip mill, and based on this measurement value, culan is controlled to a predetermined value. Control for operating the actuator is being performed.

In order to control the crown on the delivery side of the finishing rolling mill to a predetermined value in the longitudinal direction of the rolling mill under disturbance against crown control such as acceleration / deceleration of rolling mill and temperature fluctuation of rolled material, an intermediate stand of the finishing rolling mill is used. It is desirable that the crown on the delivery side is also controlled to be constant in the longitudinal direction of the rolled material. Correspondingly, install a crown measuring device on the exit side of the intermediate stand of the finish rolling mill, and operate the crown control actuator of the stand so as to control the crown to a predetermined value based on the measured value. Are believed to be effective.

[0004]

However, when the crown control actuator of the stand is operated,
The flatness on the exit side of the stand also changes. The flatness on the delivery side of the intermediate stand has an allowable operating range, and operating the crown control actuator beyond this range causes a problem in operating. As a method of preventing this, it is possible to install the stand output side flatness meter together and use the measured value to control the stand output side crown within the flatness allowable range.

However, since the flatness meter generally detects the flatness by an optical method, like the output side of the intermediate stand,
There are many restrictions on the installation space, and it is difficult to perform accurate measurements in an environment where roll coolant, strip coolant, etc. scatter.

The present invention has been made to solve the above-mentioned conventional problems, and is a method for controlling the crown and shape of a rolling mill, which enables crown control without deviating the flatness from the range desired in quality and operation. The purpose is to provide.

[0007]

DISCLOSURE OF THE INVENTION The present invention has a crown measuring device on the entrance side and the exit side of a single stand or a specific stand of a tandem rolling mill, and uses the measured values of the crown measuring devices on the entrance side and the exit side. The flatness of the stand is calculated, and the above object is achieved by operating the actuator for crown control of the stand based on the measurement value of the crown measuring device on the output side within the allowable operating range of the flatness. Is.

[0008]

According to the present invention, the crown measuring device is installed on the entrance side and the exit side of the single stand or the specific stand of the tandem rolling mill, and the flatness of the stand is determined from the measured values of the crown measuring device on the entrance side and the exit side. Calculate the degree.

The crown and flatness cannot be controlled simultaneously,
When the crown control actuator is operated, the output side flatness also changes. The flatness has a permissible range for operation, and operating a crown control actuator beyond this range causes operational problems.

Therefore, in the present invention, based on the flatness obtained above, when the flatness reaches the allowable range boundary value, the operation of the crown control actuator in the direction exceeding the allowable range boundary value is interrupted. As a result, the crown control can be performed without deviating the flatness from the range desired in quality and operation.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings.

In this embodiment, the control method of the present invention is applied to 5 stands of a 7-stand finishing rolling mill of a hot strip mill.

FIG. 1 is a block diagram showing the configuration of the control system of this embodiment.

In FIG. 1, 1 is a fourth stand, 2 is a 5th stand, 3 is a 6th stand, 4 is a 5th stand entrance side crown measuring device, and 5 is a 5th stand exit side crown measuring device. Further, 6 is a fifth stand vendor control device, 7
Is a fifth stand crown controller, 8 is a fifth stand flatness calculator, 9 is a control computer, and 10 is a material to be rolled.

This rolling mill has a work roll bending device as an actuator for crown control, and a crown measuring device 4 on the inlet side and the outlet side of the fifth stand.
And 5 are installed, and the fifth stand entry side and the exit side crowns Ch 4 and Ch 5 (mm) of the rolled material 10 and the fifth stand entry side and the exit side plate thickness h4 and h5 (mm) are continuously formed. To be measured.

The fifth stand exit side flatness computing device 8 uses these measured values and the shape change coefficient ξ5 of the fifth stand set by the control computer 9, and a known rolling theoretical formula (for example, Iron and Steel Institute of Japan "Theory and Practice of Sheet Rolling"
P. 99), the elongation difference at the 5th stand exit side is ε5 (m
m) is calculated by the following equation (1).

Ε5 = ξ5 × (Ch 4 / h4-Ch 5 / h5) (1)

Further, a known theoretical formula (P.96, ibid.).
5th stand outgoing side flatness (steepness) λ5 (%)
Is calculated by the following equation (2).

Λ5 = (2 / π) × √ (ε5) × 100 (2)

The calculated value is output to the fifth stand crown controller 7.

In the fifth stand controller 7, the fifth stand outlet crown Ch 5 (mm) input from the fifth stand outlet crown controller 5 is changed downward, and the fifth stand vendor is changed by the following equation (3). The amount ΔF5 (t) is calculated.

ΔF5 = 1 / (δCh 5 / δF5) × (Ch 5 -Ch 5 ^* ) (3)

However, δCh 5 / δF5 is the influence coefficient of the fifth stand bender on the fifth stand exit side crown,
Ch 5 ^* is the fifth stand output side crown target value (mm), which is calculated by the setting calculation function of the control computer 9 and is set in the fifth stand crown control device 7.

The calculated fifth stand vendor change amount is
It is output to the fifth stand bender control device 6 to change the fifth stand bender force.

Further, in the fifth stand crown controller 7, the fifth stand exit side flatness (steepness) λ during the above control.
5 (%) is monitored, and when this value reaches the allowable range boundary value, the calculation of the fifth stand-vendor change amount ΔF5 (t) in the direction exceeding the allowable range boundary value is interrupted.

The fifth flat stand-out side flatness allowable range used at this time is suitable for the material to be rolled 10 by searching the table similarly classified by the plate thickness, the plate width, and the steel grade by the control computer 9. The value is calculated and set in the fifth stand-crown controller 7.

Although the tandem rolling mill has been described as an example in the present embodiment, the present invention is not limited to this, and it is apparent that the present invention can be applied to a single stand.

[0028]

As described above, according to the present invention,
A crown measuring device is installed on the entrance side and exit side of a single stand or a specific stand of a tandem rolling mill, and the flatness of the stand is calculated from the measured values of the entrance and exit crown measuring devices, and the crown on the exit side is calculated. Based on the measured value of the measuring device, operate the crown control actuator of the stand and monitor the flatness of the stand. If this value reaches the allowable range boundary value, it exceeds the allowable range boundary value. Since the operation of the actuator for controlling the crown of the stand in the direction is interrupted, it is possible to control the crown without deviating the flatness from the range desired in quality and operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a control system according to this embodiment.

[Explanation of symbols]

 1 ... 4th stand 2 ... 5th stand 3 ... 6th stand 4 ... 5th stand 5th stand entrance side crown measuring device 5 ... 5th stand exit side crown measuring device 6 ... 5th stand vendor control device 7 ... 5th stand crown control Device 8 ... Fifth stand exit side flatness computing device 9 ... Control computer 10 ... Rolled material

Claims (1)

[Claims] 1. A single stand or a tandem rolling mill has a crown measuring device on the entrance side and the exit side of a specific stand, and calculates the flatness of the stand from the measured values of the crown measuring devices on the entrance side and the exit side, A crown / shape control method for a rolling mill, comprising operating an actuator for crown control of the stand on the basis of a measured value of a crown measuring device on the delivery side within an allowable operating range of flatness.