JP2000218314A - Cluster rolling mill and plate shape control method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In the case of an off-center of a rolled material, a shape detector cannot accurately detect the shape of a steel sheet. In addition, shape control of a steel sheet having a composite elongation shape caused by off-center cannot be performed. A rolled material that has passed through a cluster rolling mill body 11
Detecting the plate shape of 21 and showing the strain distribution in the rolled material 21 4
A second-order normalized orthogonal function is obtained, and a deviation between the actually measured value and the target value of the shape mode coefficients A ₁ and A ₃ of the fourth-order normalized orthogonal function and correction values α and β of the off-center amount x of the rolled material 21 are used. Then, the control amount of the leveler and the bender of the cluster rolling mill main body 11 is determined, and the plate shape of the rolled material 21 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a cluster rolling mill and a sheet shape control method.

[0002]

2. Description of the Related Art As is well known, a cluster rolling mill is a rolling mill in which a work roll is supported by one or more backup rolls or intermediate rolls. 2), a pair of work rolls are arranged so as to be surrounded by a backup roll and an intermediate roll.

[0003] By the way, not only work rolls but also rolled materials to be rolled by this cluster rolling mill are required.
Intermediate rolls and backup rolls also affect. Therefore, in the plate shape control using the cluster rolling mill, it is necessary to precisely control these various factors. For this reason, conventionally, various techniques for controlling the plate shape of a rolled material with high accuracy using a cluster rolling mill have been proposed.

For example, Japanese Patent Application Laid-Open No. 61-255710 proposes a shape control apparatus using a cluster rolling mill provided with a backup roll crown adjustment servo system, a roll bender servo system, and a reduction leveling servo system. . In this shape control device, before rolling, a control signal is output to a backup roll crown adjustment servo system to preset a backup roll crown. A control signal is output to the step-down leveling servo system based on the first-order shape mode coefficient A ₁ in the normalized orthogonal function (Legendre's normalized orthogonal function), and the shape mode coefficient A ₁
Is controlled to a target value, and a control signal is output to the roll bender servo system based on the secondary shape mode coefficient A ₂ so that the feedback control is performed so that the shape mode coefficient A ₂ becomes the target value. By performing the above, the plate shape of the rolled material is controlled with high accuracy.

However, a shape control device using a cluster rolling mill proposed in Japanese Patent Application Laid-Open No. 61-255710 discloses a
Although effective for rolling of rolled material made of carbon steel, the rolling of rolled material made of relatively hard stainless steel has a "composite elongation" in which the elongation is asymmetric with respect to the plate center during rolling.
Therefore, shape control with desired accuracy could not be performed.

Accordingly, the present inventors have previously disclosed in Japanese Patent Laid-Open No. 10-32
Japanese Patent Application Laid-Open No. 8712 proposes a cluster rolling mill capable of performing shape control with desired accuracy and a control method thereof.

FIG. 5 is an explanatory view showing an outline of a control method of a cluster rolling mill according to this proposal. In the cluster rolling mill 1 shown in FIG.
By using the shape detector 2 provided on the exit side of the above, a shape signal representing the shape elongation of each point obtained by dividing the shape of the steel plate 3 in the width direction of the steel plate 3 is detected. The shape detector 2 is made of a roll in which load cells are embedded vertically and horizontally at a constant pitch in the axial direction and the circumferential direction, and the steel sheet 3 is wound around a part of the outer peripheral surface of the shape detector 2. By measuring the tension of the steel plate 3 at the position where each load cell contacts, the shape elongation is detected.

In this ST01, a rolling process computer (not shown) that supervises the line prior to the determination of the rolling conditions is used to determine the type of steel, the thickness, the width, the rolling reduction, the temperature of the steel material at the inlet, etc. The conditions are inputted to the shape control controller 5, and the shape control controller 5 generates a backup roll crown control signal based on these.
Output 6a to preset the backup roll crown.

Next, in ST02, a normalization orthogonal function is constructed by substituting the detected shape signal (shape elongation rate) into a fourth-order normalization orthogonal function stored in the shape control controller 5. Shape mode coefficients A _{1 to} A
Calculate ₄ . Thus, the shape of the steel plate 3 is mathematically approximated by a fourth-order normalized orthogonal function. Here, an expression for calculating the shape mode coefficients A _{1 to} A ₄ based on the shape signal detected by using the shape detector 2 is obtained as follows.

That is, the normalized coordinates in the plate width direction are
Let x be the normalized orthogonal function φ ₀(i) ~ φ_Four(i)
Is φ₀(i) = a, φ₁(i) = b · x (i), φ_Two(i)
= Cx^Two (i) + d, φ_Three(i) = ex^Three (i) + f
X (i), φ_Four(i) = g x^Four (i) + hx^Two 
(i) expressed as + k and the shape mode coefficient A₁~ A_FourIs below
It is obtained by the above expression.

[0011]

(Equation 1)

Here, symbols a to k indicate normalized orthogonal function coefficients, symbol i indicates the channel number of shape detector 2, symbol n indicates the number of channels of shape detector 2, and symbol β _i is the shape signal detected by the shape detector 2
(Elongation rate of shape).

Next, in ST03, the shape mode controller A5 calculates the shape mode coefficients A ₁ to A1 obtained in ST02.
Deviations ΔA _{1 to} ΔA ₄ between A ₄ and respective target values
Are determined, and the obtained deviations ΔA _{1 to} ΔA ₄ are corrected by a correction formula to determine the control amount.

In ST04, the shape controller 5 outputs the rolling leveling signal 7a of the cluster rolling mill 1 and the symmetrical bender control signal 8a of the intermediate roll 8 so that the control amount determined in ST03 is obtained. The shape control of the steel plate 3 is performed, and the process ends.

Here, the contents of the control signals output from the shape controller 5 to the actuators of the leveling, the intermediate roll bender and the backup roll crown control mechanism of the cluster rolling mill 1 are as follows.

The rolling leveling signal 7a is effective for shape control when the shape of the steel sheet 3 is one-sided elongation, and the deviations ΔA ₁ and ΔA ₃ obtained based on the shape mode coefficients A ₁ and A ₃ are used as control target quantities. Is output to the actuator of the work roll leveler. If the control output value (deviation ΔA ₁ , ΔA ₃ ) is a positive value, the working side (O / S side) is rolled, while if the control output value is a negative value, the driving side is rolled. (D / S side) is rolled.

[0017] A is symmetric shape symmetrical intermediate roll bender control signal 8a steel plate 3, is effective for shape control of the steel plate 3 at the middle elongation or ear elongation, the intermediate roll bender actuator, shape modes factor A ₂ deviation .DELTA.A ₂ obtained based on the a ₄ respectively, it is outputted as the target amount of control .DELTA.A _4. Control output value (deviation ΔA ₂ ,
If ΔA ₄ ) is a positive value, control is performed to extend the edge of the steel sheet 3, while if the control output value is a negative value, control is performed to extend the center of the steel sheet 3 in the width direction. .

[0018] A shape of the split backup roll crown adjustment signal 6a steel plate 3 is symmetrical elongation medium end, it is effective to shape control of the steel plate 3 at the time quota elongation, the actuator of the split backup rolls, shape modes coefficient A ₄ outputs the deviation .DELTA.A ₄ by a target amount of control.

Asymmetric intermediate roll bender control signal 8b The shape of the steel plate 3 is asymmetrical to the left and right, which is effective for controlling the shape of the steel plate 3 during one-sided or combined elongation, and the shape mode coefficient A ₁ , A ₃
The deviations ΔA ₁ and ΔA ₃ obtained based on the respective values are output as control target amounts. And the value of the control output is
If (deviation ΔA ₁ : (−), deviation ΔA ₃ : (+)), the D / S side is lowered and the O / S side is opened, while the control output value is (deviation ΔA ₁ : (+), Deviation Δ
A _3: (-) if) is releases the D / S side as well as reduction of the O / S side.

According to the control method of the cluster rolling mill 1 proposed in Japanese Patent Application Laid-Open No. 10-328712, it is possible to satisfactorily roll the steel sheet 3 in which the composite elongation has occurred, and to greatly improve the finished quality of the steel sheet 3. Can be.

[0021]

However, the present inventors have conducted further studies in order to further improve the rolling quality. As a result, the inventors of the present invention disclosed a cluster rolling mill 1 disclosed in Japanese Patent Laid-Open No. 10-328712. It has been found that the desired finish quality of the steel sheet 3 may not be ensured depending on the control method.

That is, in the control method of the cluster rolling mill 1 proposed in Japanese Patent Application Laid-Open No. 10-328712, each control mode coefficient is determined on the assumption that the shape of the steel plate 3 is symmetric. Therefore, the center of the steel sheet 3 passing through the cluster rolling mill 1 in the sheet width direction is shifted from the center of the cluster rolling mill 1 in the sheet width direction due to, for example, meandering of the steel sheet 3. (In the present specification, such a shift phenomenon is referred to as "off-center.")
(1) The shape detector 2 erroneously detects the plate shape, and (2) it is not possible to control the steel plate 3 having an asymmetric shape. Hereinafter, these problems (1) and (2) will be described in detail.

Problem (1): Shape detector 2 erroneously detects the plate shape of steel plate 3 FIG. 6 shows a control method of cluster rolling mill 1 shown in FIG. 5 proposed in Japanese Patent Laid-Open No. 10-328712. Shape detector 2
FIG. 6A is an explanatory diagram showing an example of a result (shape signal) of detecting the plate shape of the steel plate 3, FIG. 6A shows a state where the steel plate 3 is passed through the center, and FIG. Indicates plate time. The vertical axis in FIGS. 6A and 6B indicates the detected value of the elongation of the steel sheet 3.

As described above, the control method of the cluster rolling mill proposed in Japanese Patent Application Laid-Open No. H10-328712, for example,
When the steel plate 3 has a simple ear extension shape, the steel plate 3 is corrected to have a symmetric shape with respect to the pass center of the steel plate 3. For this reason, as shown in FIG. 6A, in recognition of the plate shape of the steel plate 3 performed prior to the plate shape control, the pass center OO
The left and right detection distances l ₁ and l _{2 from} are both the same fixed value. Therefore, when the off-center of the steel plate 3 occurs as shown in FIG. 6 (b), the one end 3a of the steel plate 3 is shifted from the normal detection position, and the detected load is not detected.
For this reason, the shape detector 2 detects data in the same state as the state where the load is not detected due to the occurrence of elongation at the plate end 3a. On the other hand, at the other plate end 3b, since the load at a position inside the actual edge is detected, the detected load becomes large, and data in the same state as the “tensioned” state is detected as the shape. You. For this reason, when the steel plate 3 is off-center, the shape detector 2 erroneously detects that the steel plate 3 is in a partially stretched state and that the steel plate 3 is in a partially stretched state, as shown in the graph of FIG. I will.

Problem (2): It is not possible to control a rolled material having an asymmetric shape in the left-right direction. For example, in Japanese Patent Application Laid-Open No. 9-206812, a rolled material made of carbon steel, such as a quadruple or sixfold type, is rolled. In a conventional rolling mill, even if an off-center of the rolled material occurs, the distribution of the one-sided elongation shape is approximated by a substantially linear component of the linear equation, so that the left and right work rolls having the same shape control characteristics are opened. By performing the degree control, it is possible to relatively easily eliminate the defective shape of the rolled material.

However, as described above, not only the work roll 7 but also the intermediate roll 8 and the backup roll 6 affect the shape of the steel sheet 3 rolled by the cluster rolling mill 1 shown in FIG. For this reason, when an off center occurs in the steel sheet 3 rolled by the cluster rolling mill 1, the distribution of the shape of the rolled steel sheet 3 is not a one-sided elongation shape but a composite elongation. Approximation is no longer possible, and it is necessary to approximate using a higher-order approximation formula of a second-order component or higher.

However, in this Japanese Patent Application Laid-Open No. 9-206812, as a method of controlling the shape at the time of off-center occurrence, the off-center amount of the rolled material and the D / D of the work roll bending force are used.
The relationship with the difference between the S side and the O / S side is defined by the following equation.

[0028]

(Equation 2)

Here, each of the symbols a ₁ and a ₂ indicates a parameter determined for each coil and taper roll shape, the symbol ΔZ indicates the off-center amount of the rolled material, and the symbol ΔF indicates D / D The difference in roll bending force between the S side and the O / S side is shown.

In the control method of the cluster rolling mill proposed in Japanese Patent Application Laid-Open No. 10-328712, there is no shape mode coefficient for directly controlling the difference ΔF in roll bending force between the D / S side and the O / S side. Therefore, the equation disclosed in Japanese Patent Application Laid-Open No. 9-206812 cannot be applied to the control method of the cluster rolling mill proposed in Japanese Patent Application Laid-Open No. 10-328712, and the method disclosed in Japanese Patent Application Laid-Open No. 9-2068.
In the invention described in Japanese Patent Publication No. 12, no misrecognition of the shape of the steel plate 3 at the time of off-centering is taken into consideration at all, so that such misrecognition cannot be prevented.

Here, the object of the present invention is to
In order to solve the problem of the control method of the cluster rolling mill proposed by Japanese Patent Publication No. 12, specifically, in the case of the off-center of the rolled material, the shape detector can accurately detect the shape of the steel sheet, and the off-center An object of the present invention is to provide a cluster rolling mill and a sheet shape control method that can surely control the shape of a steel sheet having a composite elongation shape.

[0032]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, measured the off-center amount of the steel sheet at the exit side of the cluster rolling mill, and obtained the multi-order normalization obtained. Based on the deviation between the actually measured value and the target value of the odd-order shape mode coefficient in the orthogonal function and the measured off-center amount, the control amount of at least one of the leveler and the vendor of the cluster rolling mill is determined, and the determined control is determined. By controlling at least one of the leveler and the vendor so as to obtain the quantity, the inventors have found that the above-mentioned problem can be solved, and completed the present invention.

Here, the gist of the present invention is as follows.
(i) a cluster rolling mill main body, (ii) a plate shape detector provided on the output side of the cluster rolling mill main body to detect the plate shape of the rolled material, and (iii) provided on the output side of the cluster rolling mill main body. hand,
An off-center detector that detects an off-center amount which is a deviation between the center of the cluster rolling mill main body in the strip width direction of the rolled material and the center of the rolled material passing through the cluster rolling mill main body in the strip width direction; Obtain a multi-order normalized orthogonal function indicating the strain distribution in the rolled material based on the detection value of the detector,
Using the deviation between the measured value and the target value of the odd-order shape mode coefficient in the multiple-order normalized orthogonal function and the detection value of the off-center detector, the control amount of at least one of the leveler and the vendor of the cluster rolling mill is used. And a control device for determining the value.

From another aspect, the present invention detects a plate shape of a rolled material that has passed through a cluster rolling mill, and based on the detected value, generates a multi-order normalized orthogonal function indicating a strain distribution in the rolled material. Determine, using the deviation between the measured value and the target value of the odd-order shape mode coefficient in the multiple-order normalized orthogonal function, determine the control amount of at least one of the leveler and the bender of the cluster rolling mill, rolling material When controlling the sheet shape of, further, using the off-center amount that is the deviation between the center of the cluster rolling mill in the sheet width direction of the rolled material and the center in the sheet width direction of the rolled material that has passed through the cluster rolling mill, A plate shape control method characterized in that at least one of a leveler and a vendor is controlled.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a cluster rolling mill and a plate shape control method according to the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present embodiment, a case in which the shape of a steel sheet is controlled using a fourth-order normalized orthogonal function will be described as an example.

FIG. 1 is an explanatory view schematically showing a cluster rolling mill 10 according to the present embodiment. As shown in the figure, the cluster rolling mill 10 of the present embodiment includes a cluster rolling mill main body 11,
Plate shape detector 12, off-center detector 13, controller 14
And Hereinafter, these components will be sequentially described.

[Cluster rolling mill main body 11] As shown in the figure, the cluster rolling mill main body 11 of the present embodiment comprises a pair of upper and lower work rolls 15, 15 and a pair of upper and lower intermediate rolls 16, 16,
17, 17 and a pair of upper and lower large-diameter backup rolls 18, 18,
19, and a pair of upper and lower small-diameter backup rolls 20, 20. In the present embodiment, this cluster rolling mill body 11
As a result, the steel sheet 21, which is a rolled material conveyed rightward in the drawing, is rolled.

Although not shown, the cluster rolling mill main body 11 includes a leveler for controlling the rolling leveling of the cluster rolling mill main body 11 and symmetrically or asymmetrically controlling the bending of the intermediate rolls 16, 16, 17, and 17. The vendor and a crown control mechanism for controlling the crown of the backup rolls 18, 18, 19, 19, 20, 20 are incorporated.

The leveler, the bender, the crown control mechanism, the cluster rolling mill main body 11 and the like may be any known ones, and the existing ones are used in this embodiment. Therefore, description of the cluster rolling mill main body 11 having the leveler, bender, and crown control mechanisms will be omitted.

[Sheet Shape Detector 12] The plate shape detector 12 of the present embodiment is provided on the exit side of the cluster rolling mill main body 11, and detects the shape of the steel plate 21. In the present embodiment, the same one as the plate shape detector 2 in FIG. 5 described above was used. That is, the shape detector 12 is formed of a roll in which load cells are embedded vertically and horizontally at a constant pitch in the axial direction and the circumferential direction, and by winding the steel plate 21 around a part of the outer peripheral surface of the shape detector 12, The tension of the steel plate 21 at the position where each load cell contacts, that is, the shape elongation percentage of the steel plate 21 is measured. Thus, the shape signal 12A representing the shape elongation at each point obtained by dividing the shape of the steel plate 21 in the width direction is detected. The detected shape signal 12A is transmitted to a control device described later.
It is input to 14 and input to a shape corrector (not shown).

[Off-center detector 13] Cluster rolling mill body
On the output side of 12, an off-center detector 13 is provided. The off-center detector 13 detects a deviation between the center of the cluster rolling mill main body 11 in the strip width direction of the steel plate 21 and the center of the steel strip 21 passing through the cluster rolling mill main body 11 in the strip width direction as an off-center amount x. . At the same time, the width of the steel plate 21 is also measured.

Such an off-center detector 13 is not limited to a specific type, but an electromagnetic induction type measuring machine may be used in consideration of the surrounding environment of the cluster rolling mill 10 where fumes are generated. desirable. The detected off-center amount x is input to a control device 14 described later, and is corrected to correction values α and β by a rolling leveling influence coefficient corrector 23 and an asymmetric intermediate roll bender influence coefficient corrector 24 described later.

[Control Device 14] The control device 14 of the present embodiment comprises:
Based on the shape signal 12A input from the plate shape detector 12 and the off-center amount x input from the off-center detector 13, the following processing is performed.

(I) Calculation of Fourth-Order Normalized Orthogonal Function A fourth-order normalized orthogonal function indicating a strain distribution in the steel sheet 21 is obtained based on the shape signal 12A which is a detection value from the plate shape detector 12.

As described above, the shape signal 12A, which is a detection value from the plate shape detector 12, is input to a shape corrector (not shown) in the control device 14. And φ ₁ (i) = b ·
x (i), φ ₂ (i) = c · x ² (i) + d, φ ₃ (i) = e
X ³ (i) + f x (i), φ ₄ (i) = g x ⁴ (i) +
Substituted into a fourth-order normalized orthogonal function having h · x ² (i) + k. Thus, the first to fourth order shape mode coefficients A ₁
To A ₄ are obtained by the above-described equations.

[0046] (ii) a shape mode coefficient A ₁ to A ₄ of the measured value and the target value and the deviation ΔA ₁ ~ΔA calculation control unit 14 shapes mode coefficient A ₁ to A ₄ obtained by the ₄
Is an actually measured value based on the detected off-center amount x. Therefore, the deviation Δ between the actually measured values and the target values of the shape mode coefficients A _{1 to} A ₄ input in advance to the control device 14 is shown.
A _{1 to} ΔA ₄ are calculated based on the following equation.

[0047]

(Equation 3)

In the equation, the symbol A _i ^* indicates a target value of the shape mode coefficient, and the symbol A _i ^′ indicates an actually measured value of the shape mode coefficient. Where the symbol i = 0, 1, 2, 3, 4
It is. For example, assuming that the off-center amount is m channels, the correlation function f _i (x) between the off-center amount and the shape mode coefficient is as follows.

[0049]

(Equation 4)

Here,

[0051]

(Equation 5)

Χ _j (x) indicates the characteristic function of the j channel. (iii) Based on the deviations ΔA _{1 to} ΔA ₄ and the off-center amount x, the control amounts of the leveler and the bender of the cluster rolling mill 10 are determined.

That is, the present inventors investigated the influence coefficient of the generated off-center of the steel sheet on the actuators of the leveler, the intermediate roll bender, and the backup roll crown control mechanism of the cluster rolling mill body 11. As a result, it has been found that when an off-center occurs, the influence coefficient of each of the rolling leveler and the asymmetric intermediate roll bender changes temporarily according to the off-center amount.

FIG. 2A is a graph showing that the off-center amount affects the correction value α of the rolling leveling influence coefficient, and FIG. 2B is a graph showing that the off-center amount affects the correction value of the asymmetric intermediate roll bender influence coefficient. 6 is a graph showing that it affects β.

As shown in FIG. 2 (a), the correction value α of the rolling leveling influence coefficient is determined when the off-center amount is O / O from the D / S side.
As it goes to the S side, it increases monotonically, though non-linearly.
On the other hand, as shown in FIG. 2 (b), the correction value β of the asymmetric intermediate roll bender influence coefficient also shows that the off-center amount is O
It increases monotonically, though nonlinearly, toward the / S side.

That is, assuming that the actual measured value of the off-center amount is x and the correlation function between the off-center amount x and the correction value α of the rolling leveling influence coefficient is f (x), the correction value α of the rolling leveling influence coefficient is α = f (X). On the other hand, assuming that the correlation function between the off-center amount x and the correction value β of the asymmetric intermediate roll bender influence coefficient is g (x), the rolling leveling influence coefficient correction value β is obtained as β = g (x).

Therefore, in the present embodiment, the rolling leveling control amount Δ
S is obtained as ΔS = ΔA ₁ / {(1 + α) · δA ₁ / δS}. Here, the term (δA ₁ / δS) is (primary shape mode coefficient change amount) / (rolling leveling operation amount), and indicates the rolling leveling influence coefficient when the correction by the off-center amount x is not performed. . Therefore, in the present embodiment, the rolling leveling influence coefficient is changed from (δA ₁ / δS) to {(1 + α) · δA ₁ / δS} using the correction value α of the rolling leveling influence coefficient.

On the other hand, the asymmetric intermediate roll bender control coefficient ΔB is calculated by the asymmetric intermediate roll bender influence coefficient corrector 24.
ΔA ₃ / {(1 + β) · δA ₃ / δB}. Here, the term (δA ₃ / δB) is (the third-order shape mode coefficient change amount) / (asymmetric intermediate roll bender operation amount), and the asymmetric intermediate roll bender influence coefficient when the correction by the off-center amount x is not performed. Is shown. Therefore,
In the present embodiment, using the correction value β of the asymmetric intermediate roll vendor influence coefficient, the asymmetric intermediate roll vendor influence coefficient
This means that (δA ₃ / δB) has been changed to {(1 + β) · δA ₃ / δB}.

As described above, in the control device 14 according to the present embodiment, the off-center amount x is input to the rolling leveling influence coefficient corrector 23 and the asymmetric intermediate roll bender influence coefficient corrector 24 in the control device 14, respectively. Find values α and β,
When the steel plate 21 is off-centered, the control amounts corresponding to the first and third order shape mode coefficients A ₁ and A ₃ are corrected using these correction values α and β.

Therefore, in the present embodiment, the off-center amount of the steel plate 21 is detected by using the off-center detector (plate end detector) 13 provided on the exit side of the cluster rolling mill main body 11,
The deviation of the control amount due to the off-center is corrected. Therefore, according to the present embodiment, it is possible to correct the shape of the steel plate 21 with high accuracy without correcting the off-center of the steel plate 21 at all.

(Iv) Output of a control signal to a leveler or the like The cluster rolling mill body 11 is controlled so as to have the determined control amount.
A leveling signal is output to a leveler that controls the rolling leveling of the intermediate rolls, and a bending signal is output to a vendor that asymmetrically controls the bending of the intermediate rolls 16, 16, 17, and 17. Also, backup rolls 18, 18, 19, 1
A crown control signal is output to the crown control mechanism that controls the crowns 9, 20, and 20 so that ΔA ₄ is made zero. Thus, the cluster rolling mill 10 of the present embodiment
Thereby, the plate shape of the rolled material 21 is controlled.

As described above, according to the control device 14 of the present embodiment, (1) according to the rolling conditions inputted from a rolling process computer (not shown), the backup rolls 18, 19, and 20 suitable for the rolling conditions are prepared. Calculating and presetting the crown pattern and amount, (2) obtaining a fourth-order normalized orthogonal function corresponding to the strain distribution of the plate shape based on the detected value of the plate shape after rolling, (3) 4 the following measured values of the next shape mode coefficients a ₁ to a ₄ normalization orthogonal function and determining the deviation ΔA ₁ ~ΔA ₄ between the target value, the detected value x of (4) off-center detector 13, Based on the deviations ΔA ₁ and ΔA ₃ , the control amount ΔS of the leveler of the cluster rolling mill main body 11 and the asymmetric control amount ΔB of the bender are determined. (5) Rolling is performed so that the obtained control amounts ΔS and ΔB are obtained. Controls the leveling amount and intermediate roll bending amount. It, (6) the second-order coefficient A ₂ of the coefficient of normalization orthogonal function obtained is symmetrical controls bending of the intermediate rolls 16, 17 to match the target value, (7) determined normalized orthogonal the fourth order coefficient a ₄ among the coefficients of the function to control the split backup roll bearings to match the target value is carried out, respectively.

The cluster rolling mill 10 of the present embodiment is configured as described above. Next, the cluster rolling mill of the present embodiment
Operation 10 will be described. In FIG. 1, the steel plate 21 is engaged with the cluster rolling mill main body 11, and the rolling of the steel plate 21 is started. Then, the shape in the width direction of the steel plate 21 is detected by the shape detector 12 provided on the exit side of the cluster rolling mill main body 11. Further, the off-center amount of the steel plate 21 is detected by the off-center detector 13 provided on the exit side of the cluster rolling mill 11.

FIG. 3 shows the result of the shape detector 12 detecting the plate shape of the steel plate 21 by the cluster rolling mill 11 of this embodiment.
FIG. 3A is a diagram illustrating an example of (shape signal). FIG. 3A illustrates a state in which the steel plate 21 is passed through the center, and FIG.

In this embodiment, as in the conventional cluster rolling mill 1 shown in FIG.
Although there is no problem when passing through the center as shown in FIG. 3, when the center is off-center as shown in FIG.

However, in the present embodiment, the shape mode coefficients A ₁ , A ₂ , A A obtained by expanding the fourth-order normalized orthogonal function obtained based on the detected shape signal in the control device 14. ₃ , the deviation ΔA ₁ of the odd-order shape mode coefficients A ₁ and A _{3 from} the target value among A ₄ ,
ΔA ₃ and the off-center amount x are reduced by a rolling leveling influence coefficient corrector 23 and an asymmetric intermediate roll bender influence coefficient corrector 24
Using the correction values α and β corrected by the above, the control amounts of the reduction leveler and the benders of the intermediate rolls 16 and 17 are determined, and both the reduction leveling and the asymmetric control of the bending of the intermediate rolls 16 and 17 are performed. As a result, control for correcting an asymmetric shape that is erroneously recognized is performed. For this reason, FIG.
As shown in (b), after the correction by the off-center detector 13,
The shape of the steel plate 21 can be accurately recognized, and the shape of the steel plate 21 can be easily corrected to be left-right symmetric.

[0067]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A stainless steel strip is used by using a conventional cluster rolling mill 1 described with reference to FIGS. 5 and 6 and a cluster rolling mill 11 of the present embodiment described with reference to FIGS.
(Sheet thickness: 0.572 mm, board width: 1023 mm) were controlled.

FIG. 4A is a graph showing a control result obtained by using the cluster rolling mill 1, and FIG. 4B is a graph showing a control result obtained by using the cluster rolling mill 11. FIG.
(a) and FIG. 4 (b) show that the present invention was able to control the shape of the stainless steel strip symmetrically with high accuracy without any off-center correction.

(Modification) In the description of the embodiments and examples, the case where a fourth-order normalized orthogonal function is used is taken as an example. However, the present invention is not limited to such a form, and is similarly applied to a case where a second-order or higher-order normalization orthogonal function is used.

In the description of the embodiments and examples,
The control device controls both the leveler and the vendor of the cluster rolling mill body. However, the present invention is not limited to this mode, and one of the leveler and the bender of the cluster rolling mill main body may be controlled according to the control amount or the like.

Further, the cluster rolling mill used in the description of the embodiment and the examples is merely an example. As long as the cluster rolling mill performs control using a shape mode coefficient using a normalized orthogonal function as a shape approximation method of the plate shape, the same applies to a cluster rolling mill of a type other than those used in the embodiments and examples. You.

[0072]

As described above, according to the present invention, it is possible to accurately detect the shape of a steel sheet by the shape detector even when the rolled material is off center, and to control the shape of the steel sheet having a composite elongation shape caused by the off center. Could be done.

Therefore, according to the present invention, it is possible to prevent narrowing and camber at the time of rolling due to erroneous recognition of the shape of the rolled material due to the off-center, and to cope with the composite elongation of the steel sheet. Therefore, according to the present invention, it is possible to perform rolling while controlling the plate shape with high accuracy using a cluster rolling mill. The significance of the present invention having such an effect is extremely remarkable.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a cluster rolling mill according to an embodiment.

FIG. 2A is a graph showing that the off-center amount affects the correction value α of the rolling leveling influence coefficient, and FIG. 2B is a graph showing that the off-center amount corrects the asymmetric intermediate roll bender influence coefficient. 6 is a graph showing that the value β is affected.

FIG. 3 is an explanatory view showing an example of a result (shape signal) of a shape detector detecting a sheet shape of a steel sheet by the cluster rolling mill of the embodiment, and FIG. FIG. 3 (b) shows the state when the steel sheet is passed off center.

FIG. 4 (a) is a graph showing a control result when using a conventional cluster rolling mill, and FIG. 4 (b) is a control result when using a cluster rolling mill according to the present invention. FIG.

FIG. 5 is an explanatory diagram showing an outline of a control method of a cluster rolling mill proposed in Japanese Patent Application Laid-Open No. 10-328712.

FIG. 6 is an explanatory diagram showing an example of a result of a shape detector detecting a plate shape of a steel plate according to the control method of the cluster rolling mill shown in FIG. 5 proposed in Japanese Patent Application Laid-Open No. H10-328712. FIG. 6 (a) shows a state in which the steel sheet is passed through the center, and FIG.
(b) shows when the steel sheet is passed off center.

[Explanation of symbols]

 10 Cluster rolling mill 11 Cluster rolling mill body 12 Plate shape detector 13 Off-center detector 14 Control device 21 Steel plate

Claims (2)

[Claims] 1. A cluster rolling mill main body, a plate shape detector provided on an output side of the cluster rolling mill main body to detect a plate shape of a rolled material, provided on an output side of the cluster rolling mill main body, An off-center detector that detects an off-center amount that is a deviation between the center of the cluster rolling mill body in the strip width direction of the rolled material and the center of the rolled material that has passed through the cluster rolling mill body in the strip width direction; A multi-order normalized orthogonal function indicating the strain distribution in the rolled material is obtained based on the detection value of the shape detector, and the measured order value and the target value of the odd-order shape mode coefficient in the multi-order normalized orthogonal function are determined. And a control device for determining a control amount of a leveler and / or a vendor of the cluster rolling mill using a deviation of the cluster rolling mill and a detection value of the off-center detector. Rolling mill. 2. A plate shape of a rolled material that has passed through a cluster rolling mill is detected, and a multi-order normalized orthogonal function indicating a strain distribution in the rolled material is obtained based on the detected value of the plate shape. Using the deviation between the measured value and the target value of the odd-order shape mode coefficient in the normalized orthogonal function of, the control amount of the leveler and / or the bender of the cluster rolling mill is determined, and the plate shape of the rolled material is determined. When controlling, further, using the center of the cluster rolling mill in the strip width direction of the rolled material, using the off-center amount that is the deviation of the center in the strip width direction of the rolled material passed through the cluster rolling mill,
A plate shape control method, wherein the control amount is determined.