JP2001300617A - Method for controlling shape of strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for preventing troubles such as seizure of a roll in addition to improving the control capacity of a coolant and performing rolling of better shape in a method of shape control by the flow rate of a roll coolant in a cold rolling mill. SOLUTION: By this method for controlling the shape of a strip, when calculating the flow rate of the roll coolant in each zone which is divided in the width direction from the difference between the shape of the strip detected with a shape detector and the target shape, the ratio of the predetermined total amount of the roll coolant to the total sum of the flow rate of the roll coolant in every zone is determined and a value which is the calculated flow rate of the roll coolant in each zone multiplied by the determined ratio is used for shape control as a new set value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for controlling the shape of a cold rolling mill.

[0002]

2. Description of the Related Art In order to control the strip shape in cold rolling, usually, 1) the bending of the roll is changed by applying a bending force at both ends of the roll of a rolling mill or by using a shift mechanism. Method 2) Cooling control to adjust the amount of roll coolant in the width direction
There is a method of controlling the roll thermal crown, and the like.

FIG. 1 shows the configuration of a cold rolling mill. The control of the roll thermal crown is performed by detecting the shape of the strip by the detector 10 and adjusting the amount of roll coolant in each zone of the coolant devices 8 and 9 divided in the width direction based on the difference in the target shape.

As a control method using such a mechanism,
For example, in Japanese Patent Publication No. 23846/1993, the pattern P _i of the roll coolant flow rate in the i-th zone is represented by P _i = a · y _i + b · dy _i / dt + c (where y _i is the shape and a, b, c are (Constant) is disclosed.

[0005]

[Problems to be Solved by the Invention]
In the roll coolant flow control method disclosed in Japanese Patent Application Laid-Open Publication No. H10-163, the flow rate is independently calculated for each zone based on the difference between the shape of the strip detected by the detector and the target shape. However, when the deviation of the shape becomes extremely large, 1) in the zone where the roll coolant flow rate is increased, the flow rate becomes the maximum value and saturates and the control becomes impossible. 2) In the zone where the roll coolant flow rate is decreased. , The flow rate is too low and seizure occurs.
There has been a problem that the cooling of the roll itself is hindered.

An object of the present invention is to improve the flatness of a strip while stabilizing cooling by a roll coolant.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a shape of a cold rolling mill for calculating a roll coolant flow rate of each zone divided in a width direction from a difference between a shape of a strip detected by a shape detector and a target shape. In the control method, a ratio between a predetermined total amount of the roll coolant and a calculated total of the roll coolant flow rate for each zone is obtained, and a value obtained by multiplying the calculated roll coolant flow rate of each zone by the calculated ratio is obtained. This is a strip shape control method characterized in that it is used for shape control as a new set value of a zone.
Still further, there is provided a strip shape control method, wherein the total amount of the roll coolant is determined based on a strip passing speed or a roll temperature.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors considered the control of a thermal crown as follows. In each zone of the roll coolant, the absolute value of the thermal crown is not controlled, but the distribution of the thermal crown in the width direction may be controlled. From the viewpoint of rolling stability, it is preferable that the variation in the coolant amount is small. In the shape control based on the adjustment of the flow rate of the roll coolant for each zone, the shape is controlled not based on the absolute flow rate of the roll coolant in each zone but on the basis of a difference in the relative flow rate between the zones.
Therefore, the present inventors, for the flow rate of each zone calculated based on the detected value from the shape detector, by using a value obtained by multiplying the ratio of the total amount of roll coolant and the total of the calculated flow rate determined in advance. Remembering to keep the total amount constant.

In the method of the present invention, for example, when an attempt is made to decrease the flow rate in one zone, it means that the flow rates in all other zones are simultaneously increased. Thereby, the substantial adjustment range of each coolant device is expanded, and the case where the flow rate in each zone exceeds the upper limit or the case where the flow rate falls below the lower limit is greatly reduced. Therefore, the coolant control ability is improved, and seizure can be prevented. In addition, since the coolant flow rate is constant, the rolling state is more stable.

Although the total amount of the flow rate of the roll coolant may be fixed, it is desirable to adjust the flow rate based on the roll temperature from the original purpose of cooling the roll. Instead of detecting the temperature, the roll temperature may be estimated from the strip passing speed, and the total amount may be determined based on the estimated temperature.

[0011]

FIG. 2 shows the results of cold rolling according to the present invention and the conventional method. In the method of the present invention, the total amount of the roll coolant flow rate is set as a fixed value, and the value obtained by multiplying the ratio of the total value of the roll coolant flow rate value of each zone calculated from the detection data of the shape detector to the calculated value of each zone is finally set. Value. In the conventional method, the total amount of the roll clan and the flow rate is not specified, and the roll coolant flow rate value of each zone calculated from the detection data of the shape detector is used as it is as the set value. FIG. 2 shows the steepness in the plate width direction by both methods. Also, when the center in the strip width direction is 0 and the edge is 1, 1 /
FIG. 3 shows the transition of the steepness in the longitudinal direction at the point of # 2 and the edge portion. According to the method of the present invention, it was possible to perform rolling close to the steepness of 0, which is the target shape.

[0012]

As described above, according to the present invention, the controllability of the coolant is improved, and more favorable rolling can be performed. In addition, troubles such as roll seizure can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a rolling mill.

FIG. 2 is a diagram showing steepness in a plate width direction.

FIG. 3 is a diagram showing a transition of a steepness in a longitudinal direction.

[Explanation of symbols]

 1,7. Backup roll, 2,6. Intermediate roll 4,5. Work roll 3. Strip 8,9. Coolant device 10. Shape detector

Claims (2)

[Claims] 1. A shape control method for a cold rolling mill used for shape control by calculating a roll coolant flow rate of each zone divided in a width direction from a difference between a shape of a strip detected by a shape detector and a target shape. The ratio of the predetermined total amount of roll coolant to the calculated sum of the roll coolant flow rates for each zone is calculated, and the calculated value of the roll coolant flow rate for each zone multiplied by the calculated ratio is used as the new value for each zone. A strip shape control method, wherein the strip value is used for shape control as a set value. 2. The strip shape control method according to claim 1, wherein the total amount of the roll coolant is determined based on the roll temperature or the strip passing speed.