JPH07204722A - Method for controlling strip position by automatic level adjusting device - Google Patents

Abstract

PURPOSE:To improve accuracy in controlling a strip position by relatively increasing rolling reduction on the side where a strip position is shifted and thereby correcting the strip position. CONSTITUTION:A work roll 2 that comes in direct contact with a strip 1 is supported by a backup roll 3. A strip position detector 4 is installed on the entrance side of a cold rolling mill, and the position of the strip 1 is detected in the width direction. A signal from the strip position detector 4 is computed by a controller 6 with PID function. A screw down device 5 of an automatic level adjusting device in the rolling mill is controlled in driving based on the computed result, Thus, a rolling reduction on the side where the position of the strip 1 is shifted is relatively increased to correct the strip position. Consequently, the deviation of a strip position is reduced on the entrance side of the rolling mill.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strip position control method implemented on the entrance side of a cold rolling mill.

[0002]

2. Description of the Related Art Conventionally, position control in the width direction of a strip in a cold rolling mill has been performed by a steering roll installed on the inlet side of the cold rolling mill. This steering roll controls the position of the strip by changing the relative position with respect to the strip. Generally, automatic control is performed based on a signal from a strip position detecting device provided on the exit side of the steering roll. ing.

[0003]

However, when the distance between the steering roll and the frontmost stage of the rolling mill exceeds 10 m, if there is a disturbance such as camber of the strip, the steering roll alone will cause the roll to enter the rolling mill. However, the position of the strip cannot be controlled sufficiently, and the deviation of the strip in the width direction tends to increase.

The present invention was devised to solve the above-mentioned disadvantages of the prior art, and its main purpose is to control the widthwise position of the strip on the entrance side of the rolling mill with even higher precision. It is to provide a strip position control method.

[0005]

According to the present invention, a controller having a PID function calculates a signal from a strip position detecting device, and a rolling mill is operated based on the calculated value. This is achieved by drivingly controlling the reduction device of the automatic level adjusting device to relatively increase the reduction amount on the side where the strip position is deviated to correct the strip position.

[0006]

When the strip position is displaced to the work side, for example, the amount of reduction of the work side is increased and the amount of reduction of the drive side is decreased, so that a force in the drive side direction is applied to the strip. Is fixed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings.

In FIG. 1, a strip 1 which is a hot rolled steel sheet.
After passing through the pickling process to remove the scale, it is sent to a cold rolling mill.

Work rolls 2, which directly contact the front and back surfaces of the strip 1 at the frontmost stage of the cold rolling mill, are supported by backup rolls 3, respectively. At each end of the work side and the drive side of the backup roll 3, there is provided a rolling down device 5 including a hydraulic device for changing a rolling down position of the work roll 2 (gap dimension between two work rolls). ing.

On the entrance side of the cold rolling mill, a strip position detecting device 4 is installed, whereby the strip 1 is installed.
The position in the width direction of is detected. By inputting a signal from the strip position detecting device 4 to a controller 6 having a PID function and performing a calculation, a reduction command value is output to each of the two reduction devices 5.

Here, for example, when the strip position is shifted to the work side, the work side reduction amount is increased (the gap between the two work rolls 2 is reduced) and the drive side reduction amount is decreased (2 By increasing the gap between the two work rolls 2), a force in the drive side direction is applied to the strip 1 and the strip position is corrected. As a matter of course, regarding the deviation in the opposite direction, the reduction command values for the two reduction devices 5 have the opposite relationship to the above.

FIG. 2 shows a change with time of the strip position controlled by the present invention, and FIG. 3 shows a change with time of the reduction position difference. The speed at the cold rolling mill entrance side is 100 to 300 mpm.

The strip position deviation shown on the vertical axis of FIG.
This is the output of the strip position detecting device, and the case where the strip 1 is displaced to the work side is positive, and the opposite is negative.

The reduction position difference shown on the vertical axis in FIG. 3 is the difference between the command values for the two reduction devices of the controller 6, and is the work side reduction position minus the drive side reduction position.

The reduction position difference in FIG. 3 varies so that the strip position in FIG. 2 becomes zero. From FIG. 2, the maximum value of the strip position deviation is 20 mm.

FIG. 4 shows an example in which the automatic level control method of the present invention is not adopted. The maximum value of the strip position deviation in this case is 60 mm.

[0017]

As described above, according to the present invention, the deviation of the strip position on the entrance side of the rolling mill can be reduced to about 30% of that of the conventional method, which is great for improving the precision of strip position control. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus to which the present invention is applied.

FIG. 2 is a graph showing changes with time in strip position deviation according to the present invention.

FIG. 3 is a graph showing a time-dependent change in the reduction position difference according to the present invention.

FIG. 4 is a graph showing changes in strip position deviation over time according to a conventional technique.

[Explanation of symbols] 1 strip 2 work roll 3 backup roll 4 strip position detector 5 roll down device 6 controller

Claims (1)

[Claims] 1. A controller having a PID function calculates a signal from a strip position detecting device, and based on the calculated value, a stripping position is controlled by drivingly controlling a rolling down device of an automatic level adjusting device in a rolling mill. A strip position control method by an automatic level adjusting device, characterized in that the strip position is corrected by relatively increasing the amount of reduction on the side where the deviation occurs.