JPH04266413A - Method for controlling edge drop of rolling mill - Google Patents

Abstract

PURPOSE:To frexibly cope with fluctuation of width and the variation of edge drop of a base material and to enable imparting the target value of edge drop to a metal plate after rolling. CONSTITUTION:In a rolling mill 10 with mechanisms of a hydraulic cylinder 16 or the like with which tapered work rolls 12, 14 are shifted in the width direction of the metal plate 8, the thickness distribution in the end parts of the metal plate 8 is detected with a edge drop meter 20 and the work rolls 12, 14 are shifted in the width direction so as to minimize the square sum of difference between the detected thickness distribution and the target thickness distribution. In this way, the edge drop of the metal plate 8 is controlled on the target value with high accuracy. And, the deterioration of shape of the metal plate 8 accompanied to shifting the work rolls 12, 14 is prevented.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention uses a rolling mill having a mechanism for shifting work rolls with tapered end portions in the width direction of a sheet material to control the edge drop of a sheet material. Regarding control method.

0002

2. Description of the Related Art Plate materials such as steel plates are rolled to a predetermined size using a rolling mill. At this time, the rolled plate material is required to have a desired thickness accuracy.

[0003]Currently, demands for higher quality and higher precision of rolled products are becoming higher and higher, so the demand for plate thickness accuracy is not limited to strictly limiting plate thickness variation in the longitudinal direction. First, the thickness distribution in the width direction is also severely restricted.

[0004] A sudden change in thickness at the edge of a plate in the width direction is called edge drop, and in order to improve the thickness distribution in the width direction of the plate, it is necessary to reduce this edge drop (amount). be.

To reduce the amount of edge drop, there is a method in which a work roll with a tapered end is shifted in the width direction of the rolled plate according to the width of the rolled plate (roll shift method).
is commonly practiced.

In the conventional roll shift method, control is generally performed to change the shift position of the work roll when the target width of the plate changes.

[0007]

[Problems to be Solved by the Invention] However, in the conventional roll shift method, when a change in plate width occurs in a series of plates, for example, within a coil, or a change in edge drop amount occurs in a base material in a series of plates, However, there was a problem in that it was not possible to appropriately shift the roll in response to these fluctuations and changes and to precisely control the edge drop amount to the target value.

On the other hand, the shift amount of the work roll is controlled based on the difference between the edge drop of the plate material before rolling and its target value, and the difference between the edge drop of the plate material after rolling and its target value. There is a technology to
No. 507).

[0009] Also, the amount of shift of the work roll is calculated based on the rolling conditions of the plate material and the target value of the plate thickness deviation in the width direction of the plate, and the shift amount is corrected by the amount of movement of the taper start point where the work roll contacts the plate material. Therefore, there is a technique for setting the shift position of the work roll (disclosed in Japanese Patent Application Laid-Open No. 1-321007).

Therefore, all of these techniques focus on the difference (deviation) between the target value and the actual value of the plate edge drop amount, and are designed to reduce the deviation.

[0011] However, all of these techniques evaluate thickness deviations at individual measurement points and do not comprehensively consider the distribution of thickness deviations at the edge of the plate. thickness profile cannot be obtained. Furthermore, it cannot be said to be an effective means for deteriorating the shape of the ends in the width direction of the plate due to work roll shifts, and a newer technique is required to eliminate problems such as plate breakage.

The present invention was made in order to solve the above-mentioned conventional problems, and when a series of plate thickness variations occur or the amount of edge drop of the base material changes, it is possible to solve these variations and changes. It is an object of the present invention to provide an edge drop control method for a rolling mill that can appropriately perform roll shift control and accurately control the edge drop amount of a rolled plate material to a target value.

[0013]

[Means for Solving the Problems] The present invention provides a method for controlling the edge drop of a sheet material using a rolling mill having a mechanism for shifting a work roll having a tapered roll end in the width direction of the sheet material. An edge drop meter is installed on the exit side of the rolling mill, and the edge drop meter detects the thickness distribution in the width direction at the edge of the plate material, and calculates the sum of the squares of the differences between the detected plate thickness distribution and the target plate thickness distribution. The above problem is solved by determining the position in the width direction and shifting the tapered work roll in the width direction of the plate material so that the determined sum becomes the minimum.

[0014]

[Operation] In the present invention, when controlling the edge drop of a rolling mill, an edge drop meter is provided on the exit side of the rolling mill, and the edge drop meter detects the thickness distribution in the width direction at the edge of the plate material, and detects the detected plate thickness. 2 of the difference between the distribution and the target thickness distribution
The sum of the multiplication values is determined for each width direction position, and the roll is shifted in the board material width direction so that the sum becomes the minimum.

Here, the thickness distribution in the width direction at each position i of the edge of the plate measured by an edge drop meter is expressed as ht(
i ), and the target thickness distribution in the width direction at each position i is hr(i ). Difference ht(i)− between the detected plate thickness distribution and the target plate thickness distribution at each width direction position i
Work roll widthwise shift amount ΔWR that minimizes the sum of the squared value of hr(i) for each widthwise position i
Sδ (mm) can be determined using the formula shown in (1).

[0016]

[Math 1]

However, ht(i); actual plate thickness (mm) detected at the i-th detection position from the edge, hr(i
); Target plate thickness at the i-th detection position from the edge (
mm), dh(i)/dWRSδ: Ratio (referred to as influence coefficient) of the width direction shift amount ΔWRSδ to the plate thickness h(i) at the i-th measurement position.

Using this equation (1) as an evaluation function, the width direction shift amount ΔWRSδ that minimizes the evaluation function is set in the mechanism for shifting the roll in the width direction.

[0019] Therefore, when variations in plate width occur within a series of plate materials or when changes occur in the amount of edge drop in the base material, these variations and changes can be comprehensively evaluated using the evaluation function. Roll shift can be appropriately controlled in response to fluctuations and changes. Therefore, the edge drop amount of the rolled plate material can be set to the target value with high accuracy.

Furthermore, since the work roll shift amount is determined by the evaluation function, deterioration of the shape of the end of the plate due to the shift operation is prevented, and troubles such as plate breakage do not occur.

[0021]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0022] In this embodiment, for example, as shown in FIG.
The present invention is an edge drop control system that controls the edge drop amount of a plate material 8 to be rolled in a first stand rolling mill 10 of a continuous rolling mill.

As shown in FIG. 1, the rolling mill 10 includes:
Work roll 12, 1 with tapered roll end
4 is provided. These work rolls 12 and 14 are each made shiftable in the sheet width direction by, for example, a pair of hydraulic cylinders 16, and a pair of roll benders 1
8 allows bending.

[0024] Also, on the outlet side of the plate material 8 of the rolling mill 10, the actual plate thickness distribution (each position i) of the widthwise end of the rolled plate material 8 is
Edge drop meter 20 for detecting actual plate thickness
is provided. The widthwise plate thickness distribution detected by the edge drop meter 20 is input to the edge drop control section 22. Further, from the process calculator 24 for controlling the rolling process of the continuous rolling mill, the target value ht(i) of the thickness distribution in the width direction and the influence coefficient dh(i)/d WRS are obtained.
δ is input to the edge drop control section 22.

The edge drop control unit 22 calculates the shift amount Δ in the width direction of the work rolls 12 and 14 that minimizes the equation (1) above based on the input actual plate thickness hr(i).
It calculates WRSδ and outputs the shift amount ΔWRSδ to the work roll shift control section 26.

The work roll shift control section 26 operates the hydraulic cylinder 16 based on the input shift amount ΔWRSδ.

Therefore, in this embodiment, when a plate width variation occurs in the coil of the plate material 8 or a plate thickness variation occurs in the base material of the coil, measures are taken to cope with the plate width variation and plate thickness variation. The work rolls 12, 14 can be shifted appropriately. Therefore, it is possible to provide the rolled plate material 8 with the plate end thickness profile having the target value.

FIG. 2 shows an example of the detection results of the edge drop amount when the work rolls of a rolling mill are shifted by carrying out the method of the present invention. Also, for comparison, Figure 3
2 shows an example of the edge drop amount detection results when the present invention was not implemented (conventional method).

[0029] In this edge drop control, the edge drop amount is 50 mm from the edge in the width direction of the plate material.
The change within one coil is detected as the difference between the plate thickness at the position and the plate thickness at a position 10 mm from the end. Moreover, the rolling mill to which the method of the present invention and the conventional method are applied,
A first stand of a five-stand continuous cold rolling mill,
The first stand has a mechanism for shifting the tapered work roll in the width direction, and an edge drop meter is installed on the exit side of the first stand.

2(A) and 3(A) show the shift amount ΔWRSδ of the work roll, and FIG. 2(B) and FIG. 3(B) show the detected edge drop amount. It shows.

As shown in FIG. 3A, in the conventional method, the roll shift amount ΔWRSδ is set to a constant value depending on the set plate thickness. Therefore, as shown in FIG. 3B, the change in the edge drop amount becomes large due to changes in the edge drop amount of the base material, changes in the plate width, etc.

In contrast, in the method of the present invention, (
As shown in A), the roll shift amount ΔWRSδ is controlled in appropriate response to changes in the edge drop amount of the base material, plate thickness fluctuations, and the like. Therefore, as shown in FIG. 2B, it can be seen that the edge drop amount is accurately controlled to be close to the target value.

In the above embodiment, the present invention is applied to the first stand of a five-stand continuous cold rolling mill. However, the scope of application of the present invention is not limited thereto. For example, the invention can be implemented in rolling mills with other stand positions or other types of rolling mills.

[0034]

As explained above, according to the present invention, the edge drop of the plate can be reduced without being affected by disturbances such as changes in the thickness of a series of plates or changes in the amount of edge drop of the base material of the plate. It is possible to accurately set the amount to a target value. In addition, since the roll shift amount is determined so as to minimize the sum of the squares of the target thickness distribution and the detected thickness distribution at each position,
Not only can a predetermined plate edge thickness profile be obtained, but also excellent effects can be obtained, such as preventing deterioration of the shape of the plate edge and preventing problems such as plate breakage during roll shift operations.

[Brief explanation of the drawing]

FIG. 1 is a sectional view including a partial block diagram showing the overall configuration of an edge drop control system according to an embodiment of the present invention.

FIG. 2 is a diagram showing the results of implementing the present invention.
FIG. 7 is a diagram showing an example of change in edge drop amount.

FIG. 3 is a diagram showing an example of change in edge drop amount when the roll is shifted by the conventional method.

[Explanation of symbols]

8... Board material, 10...rolling mill, 12, 14...work roll, 16...Hydraulic cylinder, 20...edge drop meter, 22...edge drop control section, 24...process calculator, 26... Work roll shift control section.

Claims (1)

[Claims] 1. A method for controlling edge drop of a sheet material using a rolling mill having a mechanism for shifting a work roll having a tapered end portion in the width direction of the sheet material, comprising:
An edge drop meter is installed on the exit side of the rolling mill, and the edge drop meter detects the thickness distribution in the width direction at the edge of the plate material, and calculates the sum of the squares of the differences between the detected plate thickness distribution and the target plate thickness distribution. An edge drop control method for a rolling mill, characterized in that a tapered work roll is shifted in the width direction of a plate material so that the width direction position is determined and the determined sum is minimized.