JPH07256320A - Presetting method for rolling mill - Google Patents

Abstract

PURPOSE:To execute shape control with high accuracy by setting the reference value of back up crown at a set value for the first pass and at the actual value when a target shape is obtd. in feedback control of the previous path for the second and subsequent passes. CONSTITUTION:The reference values of the back up crown, outlet side sheet crown, roll bender, etc., are obtd. from rolling conditions in a first path reference setting section 15. The respective reference values after the second path are set from the actual values when the target shape is obtd. in the previous pass in a reduction record collecting section 14. Respective estimated values are determined in a rolling load, outlet side sheet crown and roll bender setting section 16. The deviations between the respective reference values of a reference setting section 15 or the reduction record collecting section 14 and the respective estimated values of the setting section 16 are determined and the preset value of the back up crown is determined in a back up crown and roll bender preset calculating section 17. The shape obtd. by a shape detector 7 is converted to numerical values by a functioning calculating device 8. The target shape is determined in a target shape setting circuit 9 and the manipulated variable at which the good shape is obtainable is calculated in an optimum manipulated variable calculating device 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for presetting a shape control device for a rolling mill having a backup crown adjustment and a roll bender mechanism.

[0002]

2. Description of the Related Art Small diameter work roll cluster mills are widely used in cold rolling mills for hard and thin materials. The small-diameter work roll is effective for high-pressure rolling of a hard material, but since complicated plate shape defects occur, these rolling mills are generally equipped with a plurality of shape control devices. In order to effectively operate these shape control devices and obtain a target shape, shape feedback control that operates the control device so that the target shape is obtained based on the actual shape from the shape detector is effective and widely used. There is.

However, since feedback control cannot be applied until the rolling start point reaches the shape detector, the shape control device is initially set to an optimum value (preset) in order to obtain the target shape immediately after the start of rolling. There is a need to. The following has been disclosed as a preset method of the shape control device of the cluster mill up to now.

The technique disclosed in Japanese Patent Application Laid-Open No. 61-255710 is a shape control system in which feedback control is performed by a roll bender having a good response and a backup crown is preset before rolling. The preset value of is calculated by the calculation device based on the rolling conditions. This preset calculation device performs shape prediction based on rolling conditions, and at this time, the roll bender force is set to a predetermined preset value. The set-up value of the backup crown is determined by using the relational expression of the load condition and the optimum pattern of the backup crown value which are obtained in advance based on the preset value of the roll bender force. Therefore, the preset value of the backup crown is determined only by the rolling load estimated value of the pass.

Further, in the above-mentioned setup method, the shape prediction accuracy based on the rolling conditions is limited, so that an error occurs in the setup. As a method of solving this, Japanese Patent Laid-Open No. 61-255709 describes a method of obtaining a preset error from the actual rolling condition and correcting the preset value of the next pass or the next coil. This is a method of obtaining a setting error of the backup crown by setting the shape change due to the roll bender operation amount due to the shape feedback as a setup error of the backup crown, and correcting the value of this error as the learning value of the next pass or the next coil.

As a method for further improving the preset precision of the above-mentioned conventional backup crown, Mitsubishi Heavy Industries Technical Report Vol. 25 No. 4 describes a backup crown setting method using a shape prediction model in which factors that affect the shape are handled in detail. In this method, first, the shape is estimated using the following equation. ε = α ・ (C _h / h-C _H / H) (1)

[0007]

[Equation 1]

The meanings of the symbols are as follows. ε: Elongation (shape) α: Coefficient of shape change C _h : Crown value of outlet plate C _H : Crown value of inlet plate h: Thickness of outlet plate H: Thickness of inlet plate F _j : Rolling factors that affect the crown of outlet plate (load, roll) Vendor, roll crown, backup crown, incoming side plate crown) A _j : Influence coefficient of each rolling factor on the outgoing side plate crown

From equations (1) and (2), a shape estimation equation for rolling conditions is obtained. Next, the difference Λ ₂ and Λ ₄ in elongation between the edge portion and the quarter portion and the plate center portion are given by equations (3) and (4), respectively. Λ ₂ = ε (E) −ε (C) (3) Λ ₄ = ε (Q) −ε (C) (4) Here, the meanings of the symbols are as follows. ε (E): Elongation of edge end ε (Q): Elongation of quarter part ε (C): Elongation of center part Λ ₂ : Difference in expansion of edge end Λ ₄ : Difference of expansion in _quarter part

Introducing the evaluation function J shown in equation (5),
In this method, the backup crown value that minimizes J is used as the preset value. J = Λ ₂ ² + Λ ₄ ² (5)

[0011]

However, the above-mentioned prior art has the following problems. The plate shape is as described above
It is shown by the equation (1), where the output side plate crown C _h is
It is estimated based on each set value in equation (6). C _h = f (P, C _r , C _H , Y _j , P _j ) (6) Here, the meanings of the symbols are as follows. P: Rolling load C _r : Roll crown Y _j : Backup crown P _j : Roll bender force

In order to obtain a good target shape, the elongation in the plate width direction is uniform, that is, ε = 0 in the equation (1). Therefore, Y _j of the equation (6) is determined so that the output side plate crown C _h becomes the equation (7). C _h = hC _H / H (7) As can be seen from the formulas (6) and (7), the optimum backup crown setting needs to be determined based on the exit plate crown of the pass.

The conventional backup crown presetting method disclosed in Japanese Patent Laid-Open No. 61-255710 is a method of setting an optimum backup crown from the rolling load, and the change of the outgoing side plate crown is not taken into consideration. There is a problem with preset accuracy.

On the other hand, in the prior art as disclosed in Japanese Patent Laid-Open No. 61-255709, the preset error of the previous pass can be corrected by the preset error learning method, but the backup crown setting method of the next pass is disclosed. Sho 6
This is similar to the prior art as described in Japanese Patent Publication No. 1-255710, and a preset error corresponding to the shape change due to the change of the exit side plate crown of the next pass always occurs.

Further, Mitsubishi Heavy Industries Technical Report Vol. 25 No. Four
The conventional technology as described in is a method of calculating the preset value of the backup crown from the model for predicting the shape in consideration of the rolling factor to the exit side plate crown,
The shape prediction model can improve the preset accuracy of the conventional techniques as described in JP-A-61-255710 and JP-A-61-255709, but has the following problems.

As the rolling progresses, the initial roll profile of each roll changes due to the heat crown, but since the effect of the heat crown on the exit side plate crown is not taken into consideration in this estimation model, each pass is followed. Preset error occurs. To solve this, find the setting error of the backup crown based on the actual value of the previous pass,
A method of correcting the estimated value of the next pass can be considered, but in this case a learning calculation is required for each pass, and there is a problem that the rolling of the next pass cannot be started immediately after the end of the previous pass due to the learning calculation process between passes. .

In addition to the above, the backup crown control has a slower response than the roll bender and may not operate effectively during acceleration, but a backup crown and roll bender preset method in consideration of responsiveness is required. .

The present invention has been made to solve the above problems, and can compensate for shape change disturbances such as heat crowns, which are difficult to predict, without learning and calculating for each path, and also can respond to backup crowns. An object of the present invention is to provide a method for setting up a highly accurate shape control device of a cluster mill in consideration of the property.

[0019]

Means and Actions for Solving the Problems The above problems can be solved by the following means. The preset calculation of the backup crown in the present invention uses equation (8) as a basic equation.

[0020]

[Equation 2]

However, Δ ₁ P = P-P ^* Δ _{1 Ch} = C _h -C _h ^* Δ ₁ P _IMR = P _IMR -P _IMR ^* The meanings of the symbols are as follows. Y _j ^* : Backup crown reference value P ^* : Rolling load reference value _Ch ^* : Outgoing plate crown reference value P _IMR ^* : Intermediate roll bender force reference value P: Rolling load estimated value C _h : Outgoing plate crown estimated value P _IMR : Intermediate roll bender force setting value

[0022]

[Equation 3]

[0023]

[Equation 4]

[0024]

[Equation 5]

In equation (8), first set each reference value.
U Backup crown reference value Y _j ^*, Rolling load standard
Value P^*, Output plate crown reference value C_h ^*, And middle low
Rubender force reference value P_IMR ^*The optimum shape is obtained in the first pass.
Are classified according to rolling conditions such as strip width and roll size.
Set the calculated value. For each reference value after the second pass
The shape feedback control in the previous pass.
Set the actual value when the mark shape was obtained.

Next, each estimated value is obtained. Rolling load estimate P
Is calculated using the rolling load formula from the rolling conditions of the pass. The estimated value C _h of the outlet plate crown value is calculated from the above-mentioned formula (7) based on the inlet and outlet plate thickness and the inlet plate crown. Further, the intermediate roll bender force setting value P _IMR is a value set according to a predetermined rolling condition. The rolling load obtained above, the estimated value of the delivery side plate crown, and the deviation Δ between the set value and the reference value of the intermediate roll bender force Δ
₁ P, _{Δ 1} C _h, obtaining a delta ₁ P _IMR.

Here, the coefficient of influence of each backup crown is the coefficient of change of the backup crown that cancels out the shape change due to the changes of the rolling load, the outlet plate crown, and the roll bender force, and is determined by a roll deformation model or rolling experiment. And give.

According to the equation (8), the reference value Y _j ^* of the backup crown is used as a constant term, and the first order of the deviation with respect to the rolling load, the output side plate crown value and the roll bender force, which are respectively multiplied by the influence coefficient of the backup crown. By the formula, the preset value Y of the backup crown of the relevant path
_j can be determined.

In the preset method according to the present invention, the backup crown value obtained by correcting the unpredictable disturbance such as the heat crown change by the shape feedback control of the previous pass is used as the reference value of the next pass. It becomes possible to set up a backup crown that compensates for shape changes that are difficult to estimate. Further, the backup crown is corrected so as to compensate for deviations from the rolling load of the relevant pass, the output side plate crown value, the roll bender force and the actual value of the previous pass, so that the target shape after the shape feedback control of the previous pass is It is possible to set the optimum backup crown obtained immediately after the start of rolling on the next pass.

Next, a method of learning the backup crown reference value for the first pass will be described. The learning method of the backup crown reference value for the first pass uses equation (9) as a basic equation.

[0031]

[Equation 6]

However, Δ ₂ P = P ^**- P Δ ₂ P _IMR = P _IMR ^** -P _IMR Here, the meanings of the symbols are as follows. Y _j ^** : Actual value of backup crown P ^** : Actual value of rolling load P _IMR ^** : Actual value of intermediate roll bender force

First, the deviation Δ ₂ P between the rolling load actual value P ^** and the rolling load estimated value P, and the intermediate roll bender force actual value P
_IMR ^** and the deviation between the intermediate roll bender force estimate P _IMR delta _2
Find P _IMR . Next, backup crown actual value Y
_j ^** , backup crown preset value Y _j , and the deviation Δ ₂ P, Δ ₂ P _IMR regarding the rolling load and the intermediate roll bender force, which are multiplied by the influence coefficient of the backup crown, respectively.
The setting error ΔY _j ^* of the backup crown reference value is obtained by the linear expression (9) consisting of the respective terms.

The setting error ΔY _j ^* of the backup crown reference value obtained by the equation (9) is multiplied by the learning gain divided by the plate width and the plate thickness and added to the backup crown value of the first pass to obtain the backup crown. Learn the reference value.

As described above, the preset method of the cluster rolling mill is obtained, which is characterized in that the reference value of the backup crown of the first pass is learned from the rolling results of the previous pass or the previous coil based on the preset error. In the preset method according to the present invention, in the case of the first pass in which there is no reference record due to the feedback control of the previous pass, the setting error is calculated from the rolling record and the reference value is corrected based on the setting error. Therefore, as the number of rolling coils increases, the setting accuracy of the first pass improves.

Next, a roll bender setup calculation before and after acceleration will be described. The roll bender setup calculation before and after acceleration uses the following formula as a basic formula. P _IMR0 = P _IMR1 + ΔP _IMR (10)

[0037]

[Equation 7]

The meanings of the symbols are as follows. P _IMR0: intermediate roll bender force of preset value P _IMR1: after acceleration of the intermediate roll bender forces P _0: pre-acceleration of the rolling load estimate P _1: rolling load estimate after acceleration

[0039]

[Equation 8]

First, the rolling load estimated value P ₀ before acceleration and the rolling load estimated value P ₁ after acceleration are calculated using a rolling load formula according to rolling conditions. Next, the deviation between the rolling load estimated value P ₀ before acceleration and the rolling load estimated value P ₁ after acceleration is obtained, and this value is multiplied by the influence coefficient of the intermediate roll bender by the load obtained by the roll deformation model or the rolling experiment, _Calculate the preset correction value ΔP _IMR of the intermediate roll bender force. If the preset value P _IMR0 of the intermediate roll bender force before acceleration is added to the preset correction value ΔP _IMR of the intermediate roll bender force, the intermediate roll bender force P _IMR1 after acceleration is obtained. here,
The set value of the backup crown is calculated from the above equation (9) with the rolling load, strip crown and roll bender force, which are the standard values, after acceleration.

From the above, the preset value of the backup crown is determined by using the rolling load, the plate crown estimated value and the roll bender force setting value of the pass as values after acceleration,
A preset method for a cluster rolling mill is obtained which is characterized by setting the roll bender force based on the difference between the rolling load predicted values before and after acceleration. According to the preset method according to the present invention, even when the backup crown adjustment cannot follow the load change during acceleration due to low responsiveness, the backup crown is preset to set the backup crown by using the predicted load value after acceleration, and before and after acceleration. If the roll bender corrects the load change of, the preset can realize the feedback control effectively from the start of feedback control to after acceleration.

[0042]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of a shape control method according to the present invention. In FIG. 1, 1 is a rolling mill, 2 is a rolling plate, 3 is a work roll, 4 is an intermediate roll, 5 is a split backup roll, 6 is a small diameter backup roll, 7 is a shape detector,
8 is a functionalized arithmetic processing device, 9 is a target shape setting circuit, 10
Is an optimum manipulated variable computing device, 11 is a roll bending mechanism, 12 is a backup roll crown adjusting mechanism, 13
Is a reduction leveling mechanism, 14 is a reduction result collection unit, 15 is a reference setting unit for the first pass, 16 is the pass rolling load, output side plate crown, roll bender setting unit, 17 is a backup crown, roll bender preset calculation unit, 18 Is a preset setting unit.

In FIG. 1, a 12-high cluster rolling mill 1
Has a structure in which a pair of upper and lower work rolls 3, an intermediate roll 4, a backup roll 5, and a small diameter backup roll 6 are arranged in a cluster. The portion surrounded by the broken line is the preset setting unit 18 of the shape control device according to the present invention. Here, the reference setting unit 15 of the first pass
Then, the respective reference values of the first pass of the backup crown, rolling load, delivery side plate crown, and intermediate roll bender, which are obtained by classifying by the rolling conditions such as plate width and roll size, are obtained.

Further, in the rolling reduction result collecting unit 14, the respective reference values for the second and subsequent passes are set from the actual values obtained when the target shape was obtained by the shape feedback control in the previous pass. The estimated values are obtained by the pass rolling load, the exit side plate crown, and the roll bender setting unit 16, the rolling load is calculated from the rolling conditions of the pass using a rolling load formula, and the exit side plate crown value is the entering and exiting plate. The intermediate roll bender force is set according to the predetermined rolling conditions, which is calculated from Eq. (7) based on the thickness and the entry side plate crown.

In the backup crown / roll bender preset calculation unit 17, each reference value obtained in the reference setting unit 15 of the first pass or the reduction result collecting unit 14, the pass rolling load, the output side plate crown, and the roll bender setting unit. The deviation of each estimated value obtained in 16 is obtained, the backup crown is preset by the linear expression of each deviation obtained by multiplying the reference coefficient of the backup crown by a constant term and multiplying by the influence coefficient of the backup crown. The value has been determined.

Further, as a portion for performing feedback control during rolling, the shape obtained by the shape detector 7 is digitized by the function-ized arithmetic unit 8, the target shape is determined by the target shape setting circuit 9, and the optimum manipulated variable arithmetic unit is operated. At 10, the operation amount is calculated so that the shape becomes good, and the roll bending mechanism 11, the backup roll crown adjusting mechanism 12, and the reduction leveling mechanism 13 are operated during rolling.

FIG. 2 is a diagram showing the roll section of the rolling mill and the shape control device. 2, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 2, 19
Is a backup crown adjusting mechanism (a), 20 is a backup crown adjusting mechanism (b), 21 is a backup crown adjusting mechanism (c), and 22 is an intermediate roll bender. In FIG. 2, the backup roll is divided into seven, and other divided rolls can be independently eccentric in the direction of the intermediate roll with respect to the fixed center portion, and an arbitrary crown pattern can be set. ing.

FIG. 3 is a diagram comparing the shape control results from immediately after the start of rolling to after acceleration according to the present invention with the case of the prior art in which the correction by the estimation of the exit side plate crown is not performed. In FIG. 3, ○ indicates the shape actual result data after the present invention is implemented,
It can be seen that good presetting is achieved by concentrating in the vicinity of Λ ₂ = Λ ₄ = 0 where the difference between the edge end of the target shape and the elongation of the _quarter part and the plate center part is 0. On the other hand, Δ indicates the data in the case of the conventional technique in which the correction by the estimation of the exit side plate crown is not performed, and the end shape is obtained and the target shape cannot be achieved.

FIG. 4 is a diagram comparing the shape results immediately after the start of rolling of each pass according to the present invention with the prior art using the exit side plate crown prediction model. In the conventional technique, the deviation between the actual shape and the target shape increases each time the path is followed. On the other hand, according to the present invention, the target shape of each pass can be achieved without learning calculation in each pass.

[0050]

As described above, according to the present invention, the first pass is set as the reference value of the backup crown,
This is learned by the rolling results, and after the second pass, the actual value after the target shape is obtained by the feedback control of the previous pass is set as the reference value, and the rolling load of the pass and the estimated value of the exit side plate crown and the roll are set. Since the configuration is such that the vendor force is corrected, it is possible to set a highly accurate backup crown that does not require learning calculation processing for disturbance compensation between paths.

Further, since the backup crown and the roll bender are preset in consideration of correcting the load change before and after the acceleration with the roll bender having good responsiveness, a good shape from the start of rolling to the acceleration can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a shape control method according to the present invention.

FIG. 2 is a diagram showing a roll unit and a shape control device of a rolling mill according to the present invention.

FIG. 3 is a diagram comparing the shape control results from immediately after the start of rolling to after acceleration according to the present invention with the case of the prior art.

FIG. 4 is a diagram comparing the shape results of each pass immediately after the start of rolling according to the present invention with the case of the conventional technique.

[Explanation of symbols]

1 Rolling mill 5 Split backup roll 6 Small diameter backup roll 11 Roll bending mechanism 12 Backup roll crown adjusting mechanism 14 Rolling record collecting unit 15 Reference setting section for the first pass 16 Pass rolling load, exit plate crown, roll bender setting section 17 Backup Crown and roll bender Preset calculation unit 18 Preset setting unit 19 Backup crown adjusting mechanism (a) 20 Backup crown adjusting mechanism (b) 21 Backup crown adjusting mechanism (c) 22 Intermediate roll bender

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location B21B 37/00 BBN 37/38 G05B 13/02 L 7531-3H 8315-4E B21B 37/00 113 Z 8315-4E 117 B (72) Inventor Tomoyuki Hirakawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Inventor, Saiichi Murata 1-2-1, Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Nobutsugu Suzuki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (3)

[Claims] 1. In a method for presetting a rolling mill having a backup crown adjustment and roll bending mechanism, a backup crown value, a rolling load, a delivery side plate crown value and a roll bender force reference value are set in advance in a first pass based on rolling conditions. It is set to a fixed value, and after the second pass, it is set to the actual value when the target shape was obtained by the feedback control of the previous pass, and the rolling load estimated value determined from the rolling conditions of that pass, the plate of that pass The estimated value of the output side plate crown determined so that the crown ratio is constant and the preset value of the roll bender force of the pass, and the deviation between the rolling load, the reference value of the output side plate crown value and the roll bender force, and the backup Using the crown reference value as a constant term, the shape determined by the roll deformation model or rolling experiment The preset value of the backup crown for the pass is determined by a linear expression of the deviation related to the rolling load, the output side plate crown value, and the roll bender force, which are respectively multiplied by the influence coefficient of the backup crown that cancels the shape change. How to preset the rolling mill. 2. A presetting method for a rolling mill according to claim 1, wherein the reference value of the backup crown of the first pass is learned from the rolling results of the previous pass or the previous coil based on the preset error. 3. The preset method according to claim 1, wherein the preset value of the backup crown is determined by using the rolling load of the pass, the estimated value of the plate crown and the set value of the roll bender force after acceleration, and the rolling load before and after the acceleration is continued. A method of presetting a rolling mill, comprising setting a roll bender force based on a difference between predicted values.