JP2001105013A - Controlling device for rolling thick plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the camber bend in a rolled stock of a thick plate during rolling at present as much as possible. SOLUTION: A distribution state of difference load in the width direction of the rolled stock in a rolling mill one pass before the final pass, for example, is detected, rolling conditions of the opening degree between rolls, the position of the guide center or the like by which a camber is controlled at the next pass are set from the distribution state of the difference load at the next pass and rolling control is executed while feeding back the actual difference load at the next pass. By setting the starting point of control which does not promote the camber at the next pass and, on and after this starting point of control and setting the rolling conditions for restraining the camber, the camber is restrained 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 problems, and an object of the present invention is 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 Differential load distribution detecting means for detecting a state in which the differential load detected in the rolling direction of the rolled material is distributed in the rolling direction, and a differential load distribution state detected by the differential load distribution detecting means, at least in the next pass rolling Rolling condition setting means for setting rolling conditions for suppressing the camber of the material.

According to a second aspect of the present invention, in the thick plate rolling control apparatus according to the first aspect of the present invention, the rolling condition setting means determines a control starting point which does not promote the camber of the rolled material in the next pass. It is characterized in that rolling conditions for suppressing the camber of the rolled material are determined from the obtained rolling conditions. In the plate rolling control device according to a third aspect of the present invention, in the first or second aspect of the invention, the rolling condition is a roll opening difference.

According to a fourth aspect of the present invention, in the thick plate rolling control device according to the first or second aspect, the rolling condition is a side guide center position.

[0008]

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 (position 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.

As shown in FIG. 1b, the computer 2 sets the roll opening as a rolling condition in the next pass, that is, the final pass, based on the difference load distribution information, as shown in FIG. To communicate. That is, Calculator 2
While reading the differential load and the length of the rolled material in the final pass, that is, the position information, the roll opening is set by performing feedback control so as to reduce the differential load, and the rolling mill controller 3
Controls the rolling mill with reference to the roll opening.

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, and a control start point that does not further promote the camber in the next pass, that is, the rolling in the final pass, is calculated from the difference load distribution. 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.

Next, in step S5, during the final pass rolling, 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 rolls are so reduced as to reduce the differential load. Feedback control of the opening difference 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. This figure 3
From FIG. 3C and FIGS. 3A and 3B, it can be seen that the difference 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 immediately before the final pass, and in the next pass, the rolling conditions are set so as not to further promote the difference load distribution, that is, to suppress camber as much as possible. Just set it. When the roll opening is used as the rolling condition, since the bending amount and the difference load have a linear relationship, the difference load is multiplied by a control gain (or control coefficient) to replace the roll with the roll opening. It becomes possible.

The control under the rolling condition for suppressing the camber (camber suppression control) can be started from the front 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 last pass, that is, when the bending of the rolled material is 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
By performing a roll opening control that does not promote the differential load distribution after the required time, for example, as shown by a two-dot chain line in FIG. 4B or 4D,
Even in the first half of the last pass, the camber can be suppressed in the latter 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 a camber amount (maximum bending amount) when 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.

Next, a second embodiment of the present invention will be described. FIG. 6 is a schematic configuration diagram showing a second embodiment of the thick plate rolling control device of the present embodiment, which is applied to a final pass and one pass before the rolling pass in a plurality of rolling processes. Here, as in the first embodiment, the last pass and the last pass are performed by the same rolling mill. In this embodiment, as shown in FIG. 6A, in the rolling before the final pass, the load detector 1 such as a load cell provided in the rolling mill detects the thick plate (rolled material) in the rolling mill before the final pass. ), The difference load at the both ends in the width direction is detected, and at the same time, the rotation pulse of the work roll WR is measured by a pulse transmitter such as an encoder to obtain position information from the metal-in. By combining the read value and the detected value of the difference load with the length (position information) of the rolled material, the difference load distribution is calculated in the same manner as in the first embodiment. In this embodiment, the camber amount is measured by a camber amount detector 5 such as an off-center meter provided on the outlet side, and the camber amount is measured and stored in combination with the position information from the metal-in. .

Based on the difference load distribution information and the camber amount information, the computer 2 sets a side guide center position as a rolling condition in a next pass, that is, a final pass, according to a logic described later, as shown in FIG. The information is transmitted to the side guide control device 4. That is, the computer 2 sets the side guide center position by performing feedback control so as to reduce the camber amount while reading the difference load of the rolled material of the final pass, the camber amount, and the position information. Reference numeral 4 controls the side guide SG with reference to the side guide center position.

The side guide center position control means, for example, as shown in FIG. 7, the position of a side guide SG for regulating the position of both sides in the width direction of the thick plate, before and after the control start point, on the side of the entrance side and the exit side. It means shifting the guides at the same time.
Here, the side guide center position CL is an intermediate position between the side guides SG on both sides in the width direction. The camber straightening force is applied to the guided thick plate by shifting the side guide center position CL both before and after the control start point enters the rolling mill and on the incoming and outgoing sides, thereby reducing 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 S11, as described above, the differential load and the camber of the rolled material before the final pass are measured, and the length of the rolled material, that is, position information is detected. Next, the process proceeds to step S12 to calculate a distribution state of the differential load in the rolling direction of the rolled material and a transition state of the camber, that is, a camber profile, based on the differential load and the measured camber value and the positional information.

Then, the process proceeds to step S13 to calculate a control start point that does not further promote the camber in the next pass, that is, the rolling in the final pass, from the difference load distribution. Here, based on the difference load distribution, control may be performed under rolling conditions for suppressing camber from the tip of the next pass. In this case, the leading end of the next pass is set as the control start point. Next, the process proceeds to step S14 to calculate 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 last pass.

Next, in step S5, during the final pass rolling, the camber amount is reduced based on the camber profile of the previous pass from the time when the required time, that is, the required time to the control start point has passed. The feedback control of the side guide center position is performed as described above. The operation of the logic of FIG. 8 is the same as that of the first embodiment except that the control output is the side guide center position (substantially the correction amount of the side guide center position) from the roll opening difference. The description is omitted because it is the same.

FIG. 9 shows a histogram of the camber amount when a thick plate having a rolling thickness of 5 to 10 mm and a rolling width of 3000 to 4000 mm is used as the rolled material and the control for suppressing the camber profile is performed. A histogram of the camber amount (maximum bending amount) when there is no camber is shown in FIG. 9B. As can be seen from the figure, when the control for suppressing the camber profile is performed, the variation of the camber is reduced, and the camber itself is also reduced. Therefore, it can be seen that this control is more effective.

[0024]

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 rolling conditions for suppressing the camber of the rolled material in the next pass are set based on the difference load distribution state, the camber of the thick plate currently being rolled can be suppressed as much as possible.

Further, according to the thick plate rolling control device of the present invention, a control starting point which does not promote the camber of the rolled material in the next pass is determined, and the rolling condition for suppressing the camber of the rolled material is determined 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 according to the present invention, in which (a) is an explanatory view of a state before a final pass, and (b) is an explanatory view of a state of a final pass. .

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;

FIGS. 6A and 6B are schematic explanatory views showing a second embodiment of the thick plate rolling control device according to the present invention, wherein FIG. 6A is an explanatory view showing a state before a final pass, and FIG. .

FIG. 7 is an explanatory diagram of side guide center position control.

FIG. 8 is a flowchart of control logic performed by the computer of FIG. 6;

9 is a histogram of a camber amount under control and non-control by the control logic of FIG. 8;

[Explanation of symbols]

 1 is a load detector 2 is a computer 3 is a rolling mill control device 4 is a side guide control device 5 is a camber amount detector WR is a work roll BUR is a backup roll SG is a side guide CL is a side guide center position

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayuki Ohara 1-chome, Kawasaki-dori, Mizushima, Kurashiki-shi, Okayama Pref.

Claims (4)

[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, A rolling condition setting means for setting rolling conditions for suppressing a camber of the rolled material at least in a next pass. 2. The rolling condition setting means finds a control start point at which a camber of a rolled material is not promoted in the next pass, and sets a rolling condition for suppressing the camber of the rolled material based on the control start point. The plate rolling control device according to claim 1. 3. The thick plate rolling control device according to claim 1, wherein the rolling condition is a roll opening difference. 4. The thick plate rolling control device according to claim 1, wherein the rolling condition is a side guide center position.