JPH06154823A - Method for deciding shift amount of work roll - Google Patents

Abstract

PURPOSE:To obtain a method for preventing the uneven wear of a roll and to decide the shift amount by which stable rolling can be executed without remarkably changing an amount of shift. CONSTITUTION:The shift amount of the succeeding material is decided of the succeeding material is decided by the cyclic shift method, a tolerance for the optimum shift position calculating area is provided on a decided amount of shift, the roll profile of the succeeding material is estimated from the roll profile (wear profile) of the preceeding material and the optimum shift position of the succeeding material is enumerated in the tolerance so that an evaluation function about smoothness of the roll profile is minimized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of determining a shift amount in plate rolling for axially shifting a work roll.

[0002]

2. Description of the Related Art Conventionally, in plate rolling, the roll passes through the plate due to the contact between the plate and the roll, so that there is a restriction that if the narrow material is rolled to a certain extent or more, the wide material cannot be rolled. There is a problem that management becomes complicated, and in order to solve such a problem of plate width regulation,
A method of shifting the work roll in the axial direction to disperse the wear is adopted. As a method of determining the work roll shift amount at this time, a method of cyclically shifting the work roll by a predetermined shift amount (Japanese Patent Laid-Open No. 61-
No. 212416), or a method of predicting a roll profile due to roll wear or thermal expansion and determining the shift amount so as to obtain a target roll profile (JP-A-63-63).
-260615) has been proposed.

[0003]

However, in the cyclic shift method as disclosed in Japanese Patent Laid-Open No. 61-212416, since the change in plate width is not taken into consideration, the amount of change in plate width and the change in cyclic shift are considered. When the amount is the same, there is a problem that uneven wear of the roll occurs. on the other hand,
In the method of setting the evaluation function to obtain the target roll profile as in the above-mentioned JP-A-63-260615,
The shift position of the next material may be larger than the shift position of the previous material, which causes unstable striping of the material and uneven elongation of the material, resulting in undesirable rolling work results. To do.

The present invention has been made in order to solve the above problems, and its object is to employ an evaluation function method for a certain allowable range based on the cyclic shift method. Thus, it is possible to obtain a method for determining the shift amount without causing uneven wear of the roll and without significantly changing the shift position of the pre-rolled material.

[0005]

The present invention is a method for determining the work roll shift amount based on the cyclic shift method, which is characterized in that the work roll shift amount is determined by the following procedure. is there. (1) Calculate the work roll profile (wear profile) at the time of rolling the next material. (2) For the calculated work roll profile, the optimum shift position of the next material is determined by obtaining a value that minimizes the evaluation function relating to the smoothness of the work roll profile, or the next material calculated by the cyclic shift method. To set an allowable range for the shift amount and determine the optimum shift position within the allowable range.

[0006]

The basic structure of the present invention is as shown in FIG.
The processing procedure will be described below with reference to FIG.

Block 1: Calculation of shift amount based on cyclic shift method This is a procedure for determining the shift amount of the next material by the conventional cyclic shift method. As shown in FIG. 2, when the current shift amount is x _i ^c , the shift amount of the next material is x
It is determined as _{i + 1} ^c = x _i ^c + Δx ^c . However, when the shift amount reaches the maximum or minimum, x
give as ^{_{i + 1 c = x i c}} -Δx c.

Block 2: Calculation of optimum shift calculation range For the shift position x _{i + 1} ^{c of} the next material determined in block 1, an allowable range of x _{i + 1} ^c ± ΔS ^c is set, and The optimum shift position of the next material calculated in block 4 only for the range is to be calculated. Further, ΔS ^c is an empirical value, which is determined based on the rolling work situation and the like.

Block 3: Calculation of Work Roll Profile for Next Material This is a procedure for calculating the wear profile of the work roll during rolling of the next material. Here, as shown in FIG. 3A, the wear profile up to now is estimated by an empirical formula based on the work roll shift amount, rolling load, rolling length, and strip width of each rolled material, and these are estimated. It can be obtained by overlapping. When the roll profile function for each roll is f _i (x), the roll profiles g _n (x) up to the _nth roll are
It can be calculated from the following formula.

[0010]

[Equation 1]

Next, a predicted roll profile f _{n + 1} (x) when the shift amount of the next material is set to 0 is calculated based on the estimated rolling load and the estimated rolling length.

Block 4: Calculation of optimum shift position of next material If the shift position of the next material is S _{i + 1} , the roll profile g _{n + 1} (x) after rolling when shifted by S _{i + 1}
3 is obtained from FIG. 3B by g _{n + 1} (x) = f _{n + 1} (x−S _{i + 1} ) + g _n (x). Here, S _{i + 1} is a value within the range of the cyclic shift reference value x _{i + 1} ^c ± ΔS ^c calculated in block 2.

Within this range, the following evaluation function is provided to determine the optimum shift position of the next material.

[0014]

[Equation 2]

This evaluation function J evaluates the differential value of the roll wear profile g _{n + 1} (x), that is, the variance of the inclination of the profile, so that the roll profile after the next material is rolled becomes smooth. The amount of shift is given. Therefore, the shift amount S _{i + 1} that minimizes the evaluation function J is set as the optimum shift amount and is set as the shift amount of the next material. In addition, the optimum shift amount is obtained by moving S _{i + 1} at a certain step interval to obtain J, and the point at which it becomes the minimum is the optimum value.

According to the method of the present invention, ΔS ^c described in the block 2 is set to 0 to be equivalent to a cyclic shift, and if the constraint of ΔS ^c is eliminated, an optimum shift giving a smooth roll profile is obtained. However, Δ
If the restriction of S ^c is removed, uneven wear of the roll can be prevented, but the shift amount per one time becomes large, and the rolling operation may become unstable.

[0017]

EXAMPLE FIG. 4 shows roll profiles (measured) after rolling 60 rolls when the conventional cyclic shift method is applied and when the method of the present invention is applied. In addition, the width schedule showing changes in the board width is also shown.

FIG. 4A shows the case where the conventional cyclic shift method is applied, and the shift amount Δx ^c (see FIG. 2) is set to 25 mm. In this case, since there is a portion where the shift amount is the same as the change amount of the plate width, uneven wear occurred in the portion circled in the figure.

On the other hand, FIG. 4 (b) shows the case where the method of the present invention is applied and the restriction of ΔS ^c is eliminated. The smoothest roll profile is obtained from the character of the evaluation function J. If the purpose is to prevent uneven wear of the rolls, this optimal shift method may be used. However, if the constraint of ΔS ^c is eliminated, the shift amount per rotation becomes large as described above. The rolling operation becomes unstable because the material stretches on one side. Therefore, FIG. 4C shows the result of the roll profile obtained by finding the optimum shift position from the evaluation function J with the constraint of ΔS ^c . In this case, ΔS ^c = 50 mm.

As can be seen from FIG. 4 (c), the smoothness of the roll profile is somewhat inferior to that of (b),
There is no significant change in the shift amount, the rolling operation is stable, and the uneven wear as shown in (a) does not exist at all.

[0021]

As described above, the present invention is a method for determining the work roll shift amount, which is based on the cyclic shift method and has an allowable range for the shift amount. Therefore, a smooth roll that does not cause uneven wear of the roll is produced. A profile can be obtained, and further, there is an effect that a stable rolling operation can be performed without a large change in shift amount. as a result,
Regarding the strip rolling schedule, it is possible to eliminate the regulation of the strip reversal schedule and the regulation of the same width continuous rolling, and there is an effect that the roll unit is reduced because the rollable amount for one set of work rolls is increased.

[Brief description of drawings]

FIG. 1 is a procedure diagram for determining a shift amount showing a basic configuration of the present invention.

FIG. 2 is an explanatory diagram for calculating a shift amount by a cyclic shift method.

FIG. 3 is an explanatory diagram for calculating a predicted roll profile of a next material from a roll profile of a previous material.

FIG. 4 is a diagram showing results of roll profiles of Examples.

Claims (2)

[Claims] 1. In plate rolling in which a work roll is shifted in the axial direction, a work roll profile at the time of rolling the next material is calculated, and an evaluation function value relating to the smoothness of the work roll profile is calculated for the calculated work roll profile. A work roll shift amount determination method characterized by determining the optimum shift position of the next material based on the result. 2. The optimum shift position of the next material is provided with a permissible range for the next material shift amount calculated by the cyclic shift method, and the optimum shift position is determined within the permissible range. The work roll shift amount determination method described.