JP2002143915A - Apparatus for controlling rolling of thick plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the camber bend on the rolled stock of a thick plate which is in rolling at present as much as possible. SOLUTION: The distribution state of difference load in the width direction of the rolled stock in a rolling mill of one pass before the final mill, for example, is detected, the inclination angle (= the deviation of the center position of the thick plate) of a conveying table for suppressing the camber in the next pass is set from the distribution state of the difference load and rolling control is performed while feeding back the difference load in the actual next pass. Moreover, by setting a control starting point by which the camber is not promoted in the next pass and setting rolling conditions for suppressing the camber after this control starting point, the camber is suppressed as much as possible and the yield of products is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for rolling a thick plate as a rolled material in a plurality of passes, and is particularly suitable for suppressing camber of the thick plate.

[0002]

2. Description of the Related Art In the rolling of a sheet material, the rolling difference is caused by a difference in hardness at both ends in the width direction of the rolled material, a difference in elongation ratio (mill constant) to both ends in the width direction of the rolling material of a rolling mill, and other various factors. A difference occurs in the thickness of both ends in the width direction of the material, and the difference in the thickness may cause bending called camber. This camber of rolled material not only reduces the yield, but when the camber is large, the rolled material may damage the rolling rolls and side guides or damage these facilities.

As a device for suppressing such a camber, there is one described in, for example, JP-A-63-90309. This publication proposes performing feedback control of the roll opening difference based on the measured rolled material camber so that no camber occurs in the next rolled material.

[0004]

However, the above-described camber suppressing method has a problem that the camber can be suppressed only from the next rolled material. In other words, it is not possible to further suppress or prevent the camber of the currently rolled material. The present invention has been developed to solve the above-described problem, and has as its object to provide a thick plate rolling control device capable of suppressing camber of a thick plate being rolled as much as possible.

[0005]

In order to solve the above-mentioned problems, a plate rolling control device according to claim 1 of the present invention comprises:
A control device for rolling a plurality of passes using a thick plate as a rolled material, a differential load detecting means for detecting a rolling mill differential load in rolling at least one or more passes before a final pass, and a differential load detecting means A differential load distribution detecting means for detecting a state in which the differential load detected in the rolling direction is distributed in the rolling direction of the rolled material; and conveying at least a next pass from the distribution state of the differential load detected by the differential load distribution detecting means. Setting means for setting a tilt angle of the table.

According to a second aspect of the present invention, in the thick plate rolling control device according to the first aspect of the present invention, the setting means determines a control starting point that does not promote the camber of the rolled material in the next pass. Then, the inclination angle of the transfer table is set.

[0007]

Embodiments of the present invention will be described below. FIG. 1 is a schematic configuration diagram showing a first embodiment of a thick plate rolling control device according to the present embodiment, in a rolling process of a plurality of passes, a final pass and one pass before (hereinafter, also referred to as a last pass before). ). Here, the last pass and the last pass are performed by the same rolling mill. And
As shown in FIG. 1a, in rolling before the last one pass, a load detector 1 such as a load cell provided in a rolling mill
A difference value of loads at both ends in the width direction of the thick plate (rolled material) in the rolling mill before the final pass is detected, that is, a difference load. At the same time, by measuring the rotation pulse of the work roll WR by a pulse transmitter such as an encoder, the pressure elongation of the rolled material is measured, that is, the position information from the metal-in is obtained. Therefore, Calculator 2 reads these pieces of information,
By combining the detected value of the differential load and the length (positional information) of the rolled material, how the differential load is distributed in the rolling direction of the rolled material, in other words, how the differential load changes Information can be obtained.

The computer 2 sets the inclination angle of the transport table in the next pass, that is, the final pass according to the logic described later, from the difference load distribution information, as shown in FIG. introduce. That is, computer 2
While reading the difference load and length of the rolled material of the final pass, that is, the position information, feedback control is performed so as to reduce the difference load, and the inclination angle of the transfer table is set. The transport table 4 is controlled so that this inclination angle is achieved. That is, by adjusting the inclination angle of the transport table 4, the center position of the thick plate S is adjusted as shown in FIG. 1C. The center position is adjusted by the tilt angle because of the own weight of the thick plate S or the thick plate S due to the angle difference between the roll axis and the table tilt angle.
It is thought to be due to the effect of twisting. By adjusting the center position of the thick plate S in this manner, a camber correcting force acts on the thick plate S, and the camber amount can be reduced.

Next, control logic performed in the computer will be described with reference to the flowchart of FIG.
In this logic, first, in step S1, as described above, the differential load of the rolled material being rolled one pass before the final pass is measured, and the length of the rolled material, that is, position information is detected. Next, the process proceeds to step S2 to detect the distribution state of the differential load in the rolling direction of the rolled material based on the measured values such as the differential load and the position information.

Next, the process proceeds to step S3 to calculate, from the difference load distribution, a control start point at which rolling in the next pass, ie, the final pass, does not further promote the camber. Here, based on the difference load distribution, control may be performed under rolling conditions for suppressing camber from the leading end of the next pass. In this case, the leading end of the next pass is the control start point. Next, step S4
Then, the required time from the metal-in to the control start point when the predicted pressure is extended in the next pass, that is, the final pass, is calculated.

Then, the process proceeds to step S5. During the final pass rolling, from the time when the required time to the control start point has passed, while measuring the differential load on the left and right sides of the rolling mill, the conveyance is performed so that the differential load is reduced. Feedback control of the tilt angle of the table is performed. Next, the operation of the logic will be described.
FIG. 3A shows the difference load distribution before the final pass, and FIG. 3B shows the difference load distribution before the final pass. Specifically, in each figure, the horizontal axis indicates the length position / pressure extension, and the vertical axis indicates the differential load / maximum differential load. Shows how are distributed. As is clear from both figures, the difference load distribution has the same tendency between the last pass and the last pass, though the difference in the difference load varies to some extent. FIG. 3C shows the state of the camber of the rolled material on the exit side of the final pass. In FIG. 3c, the horizontal axis indicates the length position / pressure extension, and the vertical axis indicates the bending amount / maximum bending amount, but how the camber is in the horizontal axis direction, that is, the rolling direction of the rolled material. Is shown.
From FIG. 3c and FIGS. 3a and 3b, it can be seen that the differential load distribution and the camber of the rolled material have the same tendency. Therefore,
For example, the difference load distribution is detected in the pass just before the last pass,
In the next pass, the transfer table tilt angle may be set so as not to further promote the difference load distribution, that is, to suppress camber as much as possible. That is, the deviation of the center position of the thick plate caused by adjusting the inclination angle of the transport table is used, and when the inclination angle of the transport table is small, the inclination angle of the transport table is equal to the deviation amount of the center position of the thick plate. Since the camber straightening force has a linear relationship with the shift amount of the center position of the thick plate, it is possible to replace the camber amount by a control gain (or control coefficient) with the inclination angle of the transfer table. Become.

The control under the rolling condition for suppressing the camber (camber suppression control) can be started from the leading end of the next pass. However, since the tip end region, which is the biting end, is in an unsteady state, when the difference between the left and right plate thicknesses, the temperature difference, and the like are large, the camber may be promoted even if the camber suppression control is performed. In that case,
It is desirable to calculate a control start point that does not promote camber in the next pass from the difference load distribution, and to perform camber suppression control therefrom.

For example, when the camber is generated in the entire length in the rolling direction in the rolling before the final pass, that is, when the bending of the rolled material is in a state as shown in FIG. When this is done, this bending tendency may be further promoted, as shown in FIG. 4b.
In this case, before the final pass, the point where the amount of bending in the rolling direction is maximum, that is, the point where the differential load is maximum is the control start point that does not promote the camber. Also, in the case of FIG. 4C in which the camber occurs only at the front end portion before the last one pass, in the next pass, the camber exists at the rear end portion as shown in FIG. 4D. In this case, the boundary point between the portion where the camber has occurred and the portion where the camber has not occurred is a control start point at which the camber is not promoted.

Therefore, the control start point is obtained from the length position of the rolled material on the outgoing side of the last one pass, and is converted into the control start point when it is replaced with the predicted length after the last pass. Time required to start control (work roll WR
After the required time, by controlling the inclination angle of the transfer table that does not promote the differential load distribution, for example, as shown by the two-dot chain line in FIG. 4B or FIG. Even in the first half, the camber can be suppressed in the subsequent second half even if the shape is the same as in the non-control state. In the actual thick plate rolling process, considering that the leading and trailing ends of the rolled material are not removed and used, especially in the removed central portion, a little camber leads to an improvement in yield. .

FIG. 5 is a histogram of the camber amount (maximum bending amount) in the case where a thick plate having a roll thickness of 5 to 10 mm and a roll width of 3000 to 4000 mm is used as a rolled material and the above-described difference load distribution control is performed. Is shown in FIG. 5a, and a histogram of the camber amount when not performed is shown in FIG. 5b. As is clear from the figure, when the difference load distribution suppression control is performed, the variation of the camber is reduced, and the camber itself is also reduced. This indicates that this control is more effective.

[0016]

As described above, according to the thick plate rolling control device of the present invention, the difference in the rolling mill at the time of rolling is detected in at least one pass before the final pass. , Detecting the distribution state of the differential load in the rolling direction of the rolled material,
Since the inclination angle of the transfer table is set in the next pass based on the difference load distribution state, the inclination angle of the transfer table is set so as not to promote the camber of the thick plate. Can be suppressed as much as possible.

According to the plate rolling control device of the second aspect of the present invention, a control start point which does not promote the camber of the rolled material in the next pass is determined, and the inclination angle of the transfer table is set therefrom. Therefore, it is possible to most effectively suppress camber of a thick plate while performing necessary rolling.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a first embodiment of a plate rolling control device of the present invention, (a) is a state explanatory view before a final pass, (b) is a state explanatory view of a final pass, ( c) is an explanatory diagram of the operation when the inclination angle of the transport table is adjusted (the direction perpendicular to the paper surface is the rolling direction).

FIG. 2 is a flowchart of control logic performed by the computer of FIG.

FIG. 3 is an explanatory diagram of a difference load distribution and a bending amount distribution.

4A and 4B are explanatory diagrams of a camber of a rolled material, in which FIG. 4A is a plan view of a rolled material after a final previous pass, FIG. 4B is a plan view of the rolled material after a final pass, and FIG. FIG. 4D is a plan view of the individual rolled material after the last pass before the final pass, and FIG. 4D is a plan view of the rolled material after the final pass.

FIG. 5 is a histogram of a camber amount under control and non-control by the control logic of FIG. 2;

[Explanation of symbols]

 1 is a load detector 2 is a computer 3 is a transport table controller 4 is a transport table WR is a work roll BUR is a backup roll S is a thick plate

Claims (2)

[Claims] 1. A control device for rolling a thick plate as a rolled material in a plurality of passes, comprising a differential load detecting means for detecting a rolling mill differential load at the time of rolling at least one pass before a final pass, A difference load distribution detecting means for detecting a state in which the difference load detected by the difference load detecting means is distributed in the rolling direction of the rolled material, and a distribution state of the difference load detected by the difference load distribution detecting means, Setting means for setting the inclination angle of the transfer table at least in the next pass. 2. The apparatus according to claim 1, wherein said setting means obtains a control start point which does not promote the camber of the rolled material in the next pass, and sets the inclination angle of the transfer table from the control start point. Plate rolling control device.