JPH1029009A - Method for controlling plate thickness in width direction of plate material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute the rolling giving a good plate thickness distribution by correcting a crossing angle of work rolls based on a deviation between the plate thicknesses at the center of the plate width and at first evaluating points and correcting shifting quantity of the work rolls based on a deviation between the plate thicknesses at the first evaluating point and second evaluating points. SOLUTION: The first evaluating points are set to positions at a prescribed distance from the center of the plate width and further, the second evaluating points are set to positions on the edge part sides at a prescribed distance from the first evaluating points as the position contriving the effect of improvement to the deviation of the plate thicknesses (edge drop) caused by the roll shift. The first evaluating points are located at the positions correctable of the plate thickness profile with the roll crossing to contrive the improvement to the deviation between the plate thicknesses at the center of the plate width generally called as a body crown and at the positions of e.g. 100mm from the plate edges. On the other hand, the second evaluating points are located at the plate edge side from the first evaluating points and are located at the positions correctable of the plate thickness profile with the roll shift to contrive the improvement to the deviation between the plate thicknesses at the positions of e.g. 100mm from the plate edges and at the positions of 10mm to about 30mm from the plate edges.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a thickness of a sheet material in a width direction, and more particularly to a mechanism for shifting a work roll tapered to a roll end portion, which is suitable for use in cold rolling of a steel sheet. The present invention also relates to a width direction thickness control method capable of favorably rolling the width direction thickness distribution of a sheet material by a rolling mill having a crossing mechanism.

[0002]

2. Description of the Related Art Among the thickness deviations in the width direction of a sheet material during rolling, a sharp decrease in the thickness at both ends in the width direction is called an edge drop, and the thickness distribution in the width direction is improved. Therefore, it is necessary to reduce the edge drop amount.

In order to improve the edge drop, for example, in Japanese Patent Publication No. 2-4364, at least one end of each of a pair of work rolls is provided with a tapered portion having a tapered portion. The work roll is shifted in the width direction of the rolled material, and the geometric shape of the roll gap is improved to reduce the edge drop (so-called roll shift method). When this is applied to a row of cold tandem rolling mills, it is described that at least a first stand is provided with a rolling stand incorporating a work roll having the tapered portion.

As a method of adjusting the shift position of the work roll, Japanese Patent Application Laid-Open No. 60-12213 discloses a method in which a measured value of an edge drop amount measured by an edge drop meter installed on the exit side of a final stand is compared with a target value. A method of performing a work roll shift control based on a comparison operation value is described.

Japanese Patent Publication No. Hei 6-71611 discloses a difference between an edge drop of a base plate before rolling by an edge drop meter installed on the entrance side of the rolling mill and a target value thereof, and an edge installed on the exit side of the rolling mill. A method of adjusting a shift amount of a work roll based on a difference between an edge drop of a product after rolling by a drop meter and a target value thereof is described.

On the other hand, a paper entitled “Sheet Crown and Edge Drop Control Characteristics” (hereinafter referred to as “literature”) published on pages 403 to 406 of the 45th Preliminary Lectures on Plastic Working (1994), By crossing the upper and lower work rolls with the backup roll on each side, the radial roll gap generated between the upper and lower work rolls toward the plate edge at the center of the plate width improves the width direction thickness distribution. It describes that there is an effect (a so-called roll cloth method).

Further, as a method of combining a roll cloth and a roll shift, Japanese Patent Application Laid-Open No. 57-206503 discloses a method in which a roll cross type rolling mill consisting of an upper roll group and a lower roll group intersecting at a predetermined intersection angle is used. It describes that by moving the relative position of a middle work roll with respect to a rolled material in the roll axis direction, uniform wear of the work roll is achieved, the frequency of roll polishing is reduced, and the basic unit of the roll is improved.

Japanese Patent Application Laid-Open No. 5-185125, which is an improvement of Japanese Patent Application Laid-Open No. 57-206503, discloses a process for changing the roll cross angle when changing the running distance by passing a coil welding point (plate joint). A method of operating a roll shift and a work roll bend force in accordance with a change timing of a roll cross angle in order to reduce a defective area of a resulting plate shape is described. In this method, when the rolling conditions change greatly at the welding point of the coil, the shift amount of the work roll is changed in the transition state of the roll cross angle from the start of the setting change of the roll cross angle to the end of the setting change, and From the roll cross angle and the work roll bend force on the optimum curve indicating the relationship between the roll cross angle and the work roll bend force with respect to the preceding coil, the optimum curve indicating the relationship between the roll cross angle and the work roll bend force with respect to the succeeding coil is obtained. The work roll bend force is changed according to an optimum pattern so that the roll cross angle and the work roll bend force can be changed in the shortest time.

[0009]

The thickness deviation in the sheet width direction is caused by the deflection or flattening of the roll during rolling. The manner of occurrence of the sheet thickness deviation depends on the position in the sheet width direction, and the roll crown is different. In the case of rolling with a normal flat work roll (only called flat roll) to which only the steel sheet is applied, as shown in FIG. , The thickness gradually decreases, and further, the thickness rapidly decreases at the width end.

On the other hand, the roll shift method described in Japanese Patent Publication No. 2-4364 has an effect of improving the thickness at the plate edge side from the taper cutting start position (taper shoulder).
As shown in the figure, it is effective to prevent a sharp decrease in the thickness at the end of the width of the sheet, but there is no effect of improving the thickness of the sheet inside the tapered shoulder (in the direction of the center of the width of the sheet). There's a problem. In FIG. 2, a solid line B is a thickness profile when the plate 10 is rolled by a flat roll, and a solid line C is a thickness profile when the plate 10 is rolled by a tapered work roll 20.

Further, in the roll cloth method described in the above-mentioned document, the thickness deviation in the sheet width direction is corrected by a radial roll gap generated from the center of the sheet width to the end of the sheet. In addition, it is possible to correct the thickness deviation from a position near the center of the width of the sheet, but there is a problem that the effect of correcting the thickness deviation at the end of the width of the sheet is small. In FIG.
A solid line D is a thickness profile when the plate 10 is rolled by crossing the work roll 22.

Japanese Patent Application Laid-Open No. 57-206503 considers only the prevention of uneven wear of a work roll. Further, the method described in Japanese Patent Application Laid-Open No. 5-185125, which is an improved technique thereof, is directed to changing the cross angle. The roll shift is only used to prevent the deterioration of the plate shape during the transition period, and the roll shift only compensates for the deterioration of the roll cross capacity. Although it is possible to correct the thickness deviation from a position close to the center of the width of the sheet, the effect of correcting the thickness deviation at the end of the width of the sheet is small.

The present invention has been made in order to solve the above-mentioned conventional problems. The present invention is directed to a range from a gentle thickness deviation occurring from the center of the sheet width toward the edge of the sheet to a thickness deviation suddenly occurring at the edge of the sheet width. It is an object to obtain a good thickness distribution over the entire width of the plate.

[0014]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for controlling a thickness of a sheet material in a width direction by a rolling mill having a mechanism for shifting a work roll tapered at a roll end and a mechanism for crossing the work roll. As a position for evaluating the sheet thickness distribution in the sheet width direction, a first evaluation point separated by a predetermined distance from the center of the sheet width and a second evaluation point separated by a predetermined distance from the first evaluation point to the plate edge side were set and detected. From the thickness distribution in the width direction of the sheet, a thickness deviation between the sheet thickness center thickness and the first evaluation point and a sheet thickness deviation between the first evaluation point and the second evaluation point are calculated, and the sheet width center is calculated. Controlling the roll cloth based on the sheet thickness deviation between the sheet thickness and the first evaluation point,
The object has been solved by controlling a roll shift based on a sheet thickness deviation between the first evaluation point and the second evaluation point.

The thickness distribution in the width direction of the plate is determined by a distribution of thickness in the width direction detected after rolling, a distribution of thickness in the width direction detected before rolling, and a rolling stand provided with a shift mechanism and a cross mechanism for the work roll. Is any one of the width-direction thickness distributions detected immediately after or any combination thereof.

For example, the width direction thickness distribution of the sheet is detected before and after rolling, and in a steady state, feedback control is performed based on the width direction thickness distribution after rolling, and the connection point of the rolled material is determined. In a transient state during passing through a rolling mill, feedforward control is performed based on the thickness distribution in the width direction before rolling.

The thickness distribution in the width direction of the sheet is determined by rolling
Before rolling and immediately after a rolling stand provided with a work roll shift mechanism and a cross mechanism, each is detected, and the roll shift and the roll cross are controlled based on the detection results at these three locations. It is.

Further, when the control based on the detection results at the three locations conflicts, the control based on the detection results on the downstream side is prioritized.

In the work roll shift, as shown in FIG.
A gap is formed between the roll 10 and the plate 10 at the end of the roll. However, when the work roll 20 is actually rolled, the thickness profile becomes as shown by a solid line C, as shown by a solid line B.
A local thickness change occurs at the end of the plate with respect to the thickness profile generated by rolling with a flat roll having no taper. On the other hand, in the work roll cloth, as shown in FIG. 3, by crossing a work roll 22 which is provided with only a roll crown and which is flat as a whole,
Between the upper and lower work rolls, a roll gap that spreads radially from the center toward the roll end is formed between the upper and lower work rolls and the plate 10, and when rolling is performed in such a crossed state, the thickness profile becomes as shown by a solid line D. In other words, with respect to the thickness profile obtained by rolling with the flat roll indicated by the solid line B, a variation in the thickness occurs in a wide range from the relatively inner side (the center side of the width) to the end of the width.

As described above, when the effect of correcting the thickness profile by the work roll cloth is compared with the effect of correcting the thickness profile by the work roll shift, the amount and form are clearly different. In addition, the edge drop of the steel sheet after cold rolling is determined by both the edge drop of the base sheet generated by the hot rolling in the previous process and the edge drop of the cold rolled sheet generated by the cold rolling. Thus, the amount and form of the edge drop after cold rolling greatly differ.

Normally, an example of the thickness distribution of a sheet material after cold rolling with a flat roll on a hot-rolled base sheet is as shown in FIG. In the range up to around A, the plate thickness gradually decreases, but on the plate end side from position A, the plate thickness sharply decreases.

As described above, in order to eliminate the thickness deviation in the width direction of the plate having the edge drop due to the two factors of the hot-rolled edge drop and the cold-rolled edge drop, and to improve the thickness distribution, a rolling mill is required. It is considered effective to use a roll having a work roll having a tapered roll end, a work roll shift mechanism, and a work roll cross mechanism.

Therefore, in the present invention, as shown in FIG. 4, a first evaluation point is set at a position away from the center of the sheet width by a predetermined amount as a position where the effect of reducing the sheet thickness deviation is intended by the roll cloth. A second evaluation point is set at a position on the end side away from the first evaluation point by a predetermined amount as a position where the effect of improving the thickness deviation (edge drop) by the roll shift is intended.
The first evaluation point is a position at which the sheet thickness profile can be corrected by a roll cloth, and the sheet thickness deviation at the center of the sheet width, which is generally called a body crown, and at the position of the sheet edge 100 mm, for example, is to be improved. On the other hand, the second evaluation point is located closer to the plate edge than the first evaluation point, and is a position where the thickness profile can be corrected by roll shift, and is usually referred to as an edge drop.
The thickness deviation from the position of about mm is to be improved.

Any one of a width direction thickness distribution after rolling, a width direction thickness distribution before rolling, and a width direction thickness distribution immediately after a rolling stand provided with a work roll shift mechanism and a cross mechanism, or any one of them. An arbitrary combination is detected, and the cross angle of the work roll cross is corrected based on the thickness deviation between the center of the width in the width direction thickness distribution and the first evaluation point.
The shift amount of the work roll shift is corrected based on the sheet thickness deviation between the evaluation point and the second evaluation point.

In particular, the thickness distribution in the width direction of the sheet is detected before and after rolling, and in a steady state,
The feedback control based on the plate shape after rolling is performed, and in the transition state where the connection point of the rolled material is passing through the rolling mill, when the feedforward control based on the plate shape before rolling is performed, higher accuracy is achieved. Can be controlled.

The thickness distribution of the sheet in the width direction is calculated by:
Before rolling, and immediately after a rolling stand provided with a work roll shift mechanism and a cross mechanism, each is detected, and based on the detection results at these three locations, the roll cloth and the roll shift are controlled. , More precise control can be performed.

When the control based on the detection results at the three locations competes, the control based on the detection result on the downstream side is prioritized, and a problem due to the control conflict can be avoided.

As described above, in consideration of the difference in the ability to correct the thickness profile of the roll cloth and the roll shift, evaluation points suitable for the respective abilities are provided, and correction is performed based on the thickness deviation of the evaluation points. FIG. 5 also shows a complicated plate profile determined by the profile of the base sheet before rolling and the change in the profile caused by cold rolling.
As shown by the solid line E, a good plate thickness distribution can be obtained over the entire plate width from the plate width center to the plate end.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, a first stand is provided with a work roll having a tapered end on one side of a roll, a roll shift mechanism for shifting the work roll, and a roll cross mechanism for crossing the work roll. An embodiment of a width direction thickness control method according to the present invention will be described in detail by taking as an example a case where the present invention is applied to a 6-stand cold tandem rolling mill.

FIG. 6 is a schematic view of a six-stand cold tandem rolling mill 30 to which the present invention is applied. The first stand 31 of the tandem rolling mill 30 includes a work roll 20 having a tapered end on one side and a roll cross control device 4 for crossing the work roll 20.
0, and a roll shift control device 42 for shifting the work roll 20 is provided. The work roll 20 receives a command from the roll cross control device 40 and controls the work roll cross to perform the roll shift control. The work roll shift can be performed in response to a command from the device 42.

In the first embodiment of the present invention, as shown in FIG. 6, a delivery side (thickness) profile meter 50 for measuring the thickness distribution in the width direction of the rolled sheet is provided with a final sixth stand 36. The measurement is performed at, for example, a one-second cycle.

The first evaluation point of the thickness deviation in the width direction obtained from the output of the outlet profile meter 50 is set at 100
The second evaluation point is set at a position of 10 mm from the edge of the plate at a position of mm, and the actual thickness deviation value of the first evaluation point and the second evaluation point is defined as follows.

C100 (h6): Actual value of sheet thickness deviation at the position of 100 mm (first evaluation point) from the center of the sheet width and the sheet edge by the outlet profile meter 50 E10 (h6): 10 from the sheet edge by the outlet profile meter 50
Actual thickness deviation value at 0mm position and 10mm position (second evaluation point)

The target value of the thickness deviation at the first evaluation point and the second evaluation point is defined as follows.

C100 (t6): 100 from center of plate width and plate edge
Target thickness deviation value at mm position (first evaluation point) E10 (t6): target thickness deviation value at 100 mm position and 10 mm position (second evaluation point) from the plate edge

The roll cloth controller 40 calculates the sheet thickness deviation of the first evaluation point C100 (h6) measured by the delivery side profile meter 50 according to the following equation. Deviation ΔC10 from target value C100 (t6)
Find 0 (h6).

ΔC100 (h6) = C100 (h6) −C100 (t6) (1)

Next, the roll cross correction amount of the work roll 20 of the first stand 31 is calculated according to the obtained deviation ΔC100 (h6). Specifically, for example, the relationship between the deviation ΔC100 (h6) and the required correction amount C1 of the cross angle of the first stand with respect to the deviation is obtained as the influence coefficient a, and is calculated by the following model equation. Can be.

C1 = a · ΔC100 (h6) (2)

Further, the roll shift control device 42
With respect to the actual value E10 (h6) of the sheet thickness deviation at the second evaluation point measured by the outlet profile meter 50,
Deviation ΔE10 from the target value E10 (t6) of the thickness deviation at the first evaluation point
(H6).

ΔE10 (h6) = E10 (h6) −E10 (t6) (3)

Next, the roll shift correction amount S1 of the work roll 20 of the first stand 31 is calculated according to the obtained deviation ΔE10 (h6). More specifically, for example, the relationship between the deviation ΔE10 (h6) and the necessary correction amount S1 of the roll shift is determined in advance as the influence coefficient b, and can be calculated by the following model formula.

S1 = b · ΔE10 (h6) (4)

The method of calculating the correction amount of the roll cross angle and the roll shift amount is not limited to the above-described model formula. For example, a method of selecting a necessary correction amount using a table created based on actual results. Etc. can also be used.

Next, the entry side (plate thickness) profile meter 52 is
FIG. 7 shows a second embodiment of the present invention, which is provided on the entry side of the first stand 31 and controls the roll cross and the roll shift based on the width direction thickness distribution of the mother plate before rolling.

In the second embodiment, the center of the plate width detected by the entry-side profile meter 52 and the distance
Thickness deviation actual value at 0mm position (first evaluation point) is C100
(H0), the sheet thickness deviation at the position of 100 mm and the position of 10 mm (second evaluation point) from the plate edge similarly detected by the entry-side profile meter 52 is defined as E10 (h0), and the target values for these are set to C100, respectively. (T0) and E10 (t0).

In the second embodiment, the target values C100 (t0) and E10 (t0) of the sheet thickness deviation with respect to the base plate are required to obtain a desired sheet thickness distribution on the exit side of the final sixth stand 36. The thickness deviation is determined in advance according to the steel type, the thickness schedule, and the like based on the actual rolling performance of the actual machine.

The method of calculating the roll cross angle correction amount C1 and the roll shift correction amount S1 is the same as that in the first embodiment, and a detailed description thereof will be omitted.

The thickness distribution in the width direction of the base plate before rolling is as follows:
For example, in the case of cold rolling, it is possible to measure by installing a thickness profile meter on the inlet side of the cold rolling mill, the outlet side of the hot rolling mill, or between the hot rolling mill and the cold rolling mill, or offline. Can be measured.

Next, the outgoing profile meter 50 similar to the first embodiment and the incoming profile meter 5 similar to the second embodiment are used.
FIG. 8 shows a third embodiment of the present invention in which 2 is used in combination.

In the third embodiment, the roll cross controller 40 based on the output of the outlet profile meter 50 is used.
A switching device 60 for controlling the control of the roll shift control device 42 and the control of the roll cross control device 40 and the roll shift control device 42 based on the output of the entry-side profile meter 52 is provided. This switching device 60
According to the tracking state of the welding point where the preceding steel sheet and the succeeding steel sheet are connected, in a steady rolling state where there is no welding point, the output of the exit profile meter 50 controls the roll cross and the roll shift in a feedback manner, and the welding point Is changed from the feedback control based on the output of the outlet profile meter 50 to the feedforward control based on the output of the inlet profile meter 52 when the welding point has passed the position of the outlet profile meter 52. Is reached, the control is returned to the feedback control based on the output of the outlet profile meter 50 again.

According to the third embodiment, in the steady state, the thickness distribution on the exit side of the final sixth stand 36 can be reliably set to the target value by the output of the exit side profile meter 50. While the point is passing through the tandem rolling mill 30, appropriate feedforward control based on the output of the entry-side profile meter 52 can be performed.

Next, in addition to the outlet profile meter 50 and the inlet profile meter 52 as in the third embodiment, immediately after the first stand 31 where the roll shift and roll cross of the work roll 20 are enabled. An intermediate (plate thickness) profile meter 54 is provided, and the roll shift control device 40 and the roll cross control device 42 are controlled by the output of the output profile meter 50, the intermediate profile meter 54, and the input profile meter 52. FIG. 9 shows a fourth embodiment of the present invention.

In the fourth embodiment, first to third
Unlike the embodiment, a position 25 mm from the plate width is defined as a first evaluation point, and the thickness deviation at the first evaluation point is defined as follows.

C25 (h6): Actual value of sheet thickness deviation at the position 25 mm from the sheet width center and the sheet edge (first evaluation point) by the outlet profile meter 50 C25 (t6): Sheet width center and sheet at the exit side of the rolling mill 2 from the end
Sheet thickness deviation target value at 25 mm position (first evaluation point) C25 (h1): Actual sheet thickness deviation value at 25 mm position (first evaluation point) from the sheet width center and the sheet end by the intermediate profile meter 54 C25 (t1): Target thickness deviation value C25 (h0) at the position 25 mm from the center of the sheet width and the end of the sheet on the exit side of the first stand (first evaluation point): 25 mm from the center of the sheet width and the position 25 mm from the end of the sheet (first Actual value of sheet thickness deviation of evaluation point) C25 (t0): 2 from the sheet width center and the sheet edge on the rolling mill entry side
Target thickness deviation value at 5 mm position (first evaluation point)

In the fourth embodiment, when an error from the target value of the width direction thickness distribution occurs simultaneously at a plurality of locations, the roll cloth control device 40 and the roll cross The switching device 62 operates so as to control the shift control device 42.

More specifically, when an error from the target value of the thickness distribution in the width direction occurs in the product shape after rolling detected by the outlet profile meter 50, the intermediate profile meter 5 is used.
The roll cross controller 40 and the roll shift controller 42 are feedback-controlled exclusively by the output of the output profile meter 50 irrespective of the output of the output profile meter 50 and the output 4.

Also, no error from the target value of the thickness distribution in the width direction occurs in the product shape after rolling measured by the outlet profile meter 50, and immediately after the first stand measured by the intermediate profile meter 54. When an error occurs in the shape of the rolled material, the roll cross control device 40 and the roll shift control device 42 are feedback-controlled by the output of the intermediate profile meter 54 regardless of the output of the entry-side profile meter 52. .

In addition, both the product shape after rolling and the shape of the rolled material immediately after the first stand measured by the outlet profile meter 50 and the intermediate profile meter 54 have an error from the target value of the width direction thickness distribution. If not,
The roll cross controller 40 and the roll shift controller 42 are feed-forward controlled by the output of the entry-side profile meter 52.

In the fourth embodiment, an intermediate profile meter 54 is provided immediately after the first stand 31 where the roll shift and roll cross are performed.
Since the thickness distribution is controlled by the output of No. 4, quick and accurate control is possible.

In some applications, the outlet profile meter 50 and the inlet profile meter 52 may be omitted, and only the intermediate profile meter 54 may be used.

The fourth embodiment is particularly caused by both the edge drop generated by the hot rolling in the previous step and the edge drop generated by the cold rolling, and these edge drops are generated between and within the coils. This is effective in reducing the amount of edge drop on the exit side of a cold rolling mill with respect to edge drop accompanied by fluctuation.

[0063]

EXAMPLES A conventional example using only a work roll shift and a first example according to the first embodiment of the present invention when rolling a tinplate steel sheet having a width of 900 mm, which has been pickled after hot rolling, are respectively described. Rolling by 20 coils, and comparing the average of the ratios (thickness defect rate in the width direction) where the thickness distribution at the 100 mm end and 10 mm end in the longitudinal direction of the steel plate were out of the predetermined control range. As shown in FIG.
The size of the taper was such that the radius was reduced by 1 mm per 300 mm of length in the barrel direction.

According to the first embodiment of the present invention, it has been confirmed that the thickness distribution in the width direction of the sheet can be remarkably improved as compared with the conventional method. Also, it was confirmed that substantially the same results as in the first example were obtained in the case of the second embodiment.

Similarly, the second embodiment according to the fourth embodiment of the present invention
FIG. 10 also shows the result of averaging the percent defective in the width direction in the embodiment.
Shown inside. It is apparent that the thickness distribution in the plate width direction can be significantly improved also in the case of the fourth embodiment as compared with the conventional method.

In the above description, the present invention has been applied to the cold rolling of a steel sheet. However, the present invention is not limited to this, and the present invention is not limited to this. It is clear that the same applies to rolling. Also, the type of rolling mill is not limited to a four-high rolling mill,
The present invention is also applicable to a high rolling mill and a six high rolling mill. Further, the number of stands is not limited to six, and the present invention is applicable to any tandem rolling mill having two or more stands. A stand provided with a work roll shift / cross mechanism is not limited to the first stand, and It may be provided not only on a single stand but also on a plurality of stands.

[0067]

According to the present invention, the thickness of the sheet extends over the entire width of the sheet, from a gradual sheet thickness deviation occurring from the center of the sheet width toward the sheet end to a sheet thickness deviation occurring abruptly at the sheet width end. The distribution can be satisfactorily rolled, and in particular, the edge drop control defect can be far reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a thickness distribution of a sheet material after cold rolling with a normal flat roll.

FIG. 2 is a diagram showing an example of a change in a thickness profile at an end portion of a plate due to a work roll shift.

FIG. 3 is a diagram showing an example of a change in a thickness profile of a plate end portion caused by a work roll cloth.

FIG. 4 is a sectional view showing positions of a first evaluation point and a second evaluation point in the present invention.

FIG. 5 is a diagram showing an example of a change in a thickness profile of a plate edge according to the present invention.

FIG. 6 is a block diagram showing a configuration of a first embodiment of the present invention applied to a 6-stand cold tandem rolling mill.

FIG. 7 is a block diagram showing the configuration of the second embodiment.

FIG. 8 is a block diagram showing a configuration of the third embodiment.

FIG. 9 is a block diagram showing the configuration of the fourth embodiment.

FIG. 10 is a diagram showing a comparison of the average of the width direction defective thickness ratio between the conventional example and the first and second embodiments of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Plate 20 ... Work roll 30 ... 6 stand cold tandem rolling mill 31 ... 1st stand 36 ... 6th (final) stand 40 ... Roll cross controller 42 ... Roll shift controller 50 ... Out side profile meter 52 ... In Side profile meter 54 ... Intermediate profile meter 60,62 ... Switching device

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasuo Yarida 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture Inside the Technical Research Institute of Kawasaki Steel Co., Ltd. (72) Inventor Hisao Imai 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki (72) Inventor Tomohiro Kaneko 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Corporation Chiba Works

Claims (7)

[Claims] When a thickness control in a width direction of a sheet material is performed by a rolling mill provided with a mechanism for shifting a work roll having a tapered roll end and a mechanism for crossing the work roll, the thickness distribution in the sheet width direction is controlled. A first evaluation point that is a predetermined distance away from the center of the plate width and a second evaluation point that is a predetermined distance away from the first evaluation point on the plate edge side are set as positions to be evaluated. Calculating a sheet thickness deviation between the sheet width center sheet thickness and the first evaluation point and a sheet thickness deviation between the first evaluation point and the second evaluation point; A roll cloth is controlled based on the sheet thickness deviation of the sheet material, and a roll shift is controlled based on the sheet thickness deviation between the first evaluation point and the second evaluation point. 2. The method according to claim 1, wherein the width direction thickness distribution of the plate is a width direction thickness distribution detected after rolling. 3. The method according to claim 1, wherein the width direction thickness distribution of the plate is a width direction thickness distribution detected before rolling. 4. The method according to claim 1, wherein the width direction thickness distribution of the plate is detected before and after rolling, and in a steady state, feedback control based on the width direction thickness distribution after rolling is performed. In a transitional state in which a connection point of a rolled material is passing through a rolling mill, a feedforward control based on a widthwise thickness distribution before rolling is performed, and a width direction thickness control method for a plate material. 5. The sheet thickness distribution of a rolled material according to claim 1, wherein the sheet thickness distribution in a width direction of the plate is detected immediately after a rolling stand provided with a shift mechanism and a cross mechanism of the work roll. A method for controlling the thickness of a sheet in the width direction. 6. The method according to claim 1, wherein the thickness distribution of the sheet in the width direction is detected after rolling, before rolling, and immediately after a rolling stand provided with a work roll shift mechanism and a cross mechanism. A method for controlling the thickness of a sheet in the width direction, wherein the roll cross and the roll shift are controlled based on detection results at three points. 7. The method according to claim 6, wherein when control based on the detection results at the three locations conflicts, control based on the detection results on the downstream side is prioritized.