JP2505989B2 - Edge-drop control method for strip rolling - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge drop control method for strip rolling by a multiple pass multi-rolling mill.

[0002]

2. Description of the Related Art In strip rolling for continuous cold rolling,
In order to perform high-speed rolling of rolled material and improvement of edge drop, multiple multiple rolling mills are installed on the rolling line to perform edge drop control.

In such equipment, a target edge drop of material at a predetermined position on the rolling line is set as a target value for edge drop control. That is, the edge drop control is a preset control for outputting a set value before rolling the material.

In this preset control, the roll barrel end of the rolling mill having a minimum number of passes is tapered (hereinafter referred to as "taper") as far as possible on the upstream side of the rolling pass of the multi-pass multi-rolling mill and within the range satisfying the constraint condition for control. It is optimum to adjust the shift in the plate width direction and roll the work roll that has become the “()” from both aspects of ensuring quality and reducing production costs.

Therefore, in the preset control, the shift amount of the work roll from the upstream of the rolling pass is calculated and preset so that the edge drop on the exit side of the final pass becomes the target edge drop and the above-mentioned constraints and optimum conditions are satisfied. Required to do so.

However, in the actual rolling, the optimum value of the work roll shift changes due to the influence of the rolling conditions such as the change of the taper portion of the work roll, the rolling load, the plate thickness or the plate width of the original plate.

Therefore, the inventors of the present invention previously proposed Japanese Patent Application No. 2-36.
As No. 211, the edge drop of the plate on the exit side of the final pass rolling mill is represented by a mathematical model using the above rolling conditions as parameters, and using this mathematical model, from the both aspects of quality assurance and production cost reduction, Has proposed a method of obtaining and presetting the work roll shift amount of the rolling mill from the upstream side such that the edge drop becomes the target value and the optimum conditions are satisfied by the constraint conditions.

[0008]

The above-mentioned Japanese Patent Application No. 2-36.
In the method of No. 211, the work roll shift amount that minimizes the evaluation function that evaluates the deviation from the target value of the edge drop is obtained by iterative calculation of the mathematical model, and depending on the rolling conditions and the initial value, the number of calculations is Can be huge.

In view of the above problems, the present invention obtains and sets the work roll shift amount of the rolling mill from the upstream side so that the edge drop on the exit side of the final pass satisfies the required accuracy without repeatedly calculating the mathematical model. An edge drop control method is provided.

[0010]

In order to achieve the above object, the present invention provides a multiple pass multiplex having a shift mechanism in the cylinder axial direction of a work roll in which the roll cylinder end is tapered during plate rolling. In a method of performing edge drop control of a plate using a rolling mill, a mathematical model of an edge drop of a rolled material expressed by a parameter including a work roll shift amount (hereinafter referred to as HCW) of each pass (hereinafter referred to as an edge drop prediction model) ) Is created in advance, and by using this edge drop prediction model, the edge drops on the exit side of the final pass rolling mill of one or more points are predicted so that they all fall within the target range set by the fuzzy set, An edge drop control for plate rolling characterized in that the relative position of the taper start point of the work roll and the end of the strip width side is set sequentially from the upstream pass rolling mill. It is a method.

[0011]

Embodiments of the present invention will now be described with reference to the drawings and the operation thereof.

An embodiment of a multi-pass multiple rolling mill to which the present invention is applied is shown in FIG. In FIG. 1, 7 is a multi-pass multiple rolling mill, and 1 is a steel plate rolled by the rolling mill. The starting point of the line is the S point, the ending point is the O point, 5 is an edge drop detector for measuring the strip thickness distribution on the rolling mill entrance side, and 8 is the strip width direction strip thickness distribution on the rolling mill exit side. Is an edge drop detector for measuring the strip width, and 6 is a strip width detector on the rolling mill entrance side.

The steel plate 1 at the point O is given a target value of edge drop. There is an n-pass (five passes in this embodiment) multiple rolling mill on the line, and each rolling mill has a work roll 2 and a backup roll 3 which are capable of shifting in the plate width direction in which the roll cylinder ends are tapered. Are equipped with.
The edge drop is improved by the shift operation of the work roll, and the operation amount is controlled by the control computer and the controller 4.

When the edge drop of the plate on the rolling mill entry side is large, the HCW of each rolling mill is set so that the contact length of the tapered portion of the work roll becomes larger on the upstream rolling mill in order to prevent the deterioration of the plate shape. Set. As a result, the reduction of the edge of the plate is reduced, so that the edge drop of the rolled plate is reduced and the plate has a uniform plate thickness in the width direction.

When setting the HCW, the magnitude of the bending force is also set at the same time so that the tension at the plate end does not become excessive.

The details of the edge drop prediction model and the edge drop control relating to the edge drop control method of the present invention will be described below.

In the present invention, the edge drop means the deviation between the plate thickness at the reference point and the plate thickness at the plate end point in the plate width direction. In that case, the reference point is an arbitrary point closer to the center of the plate than the plate end point, and the plate end point is one or more points closer to the plate side end portion than the reference point.

In this embodiment, the reference point is 10 from the end on the plate side.
An example in which the 0 mm point and the plate end point are 15 mm from the plate side end and 2
An example of 5 mm will be described. The edge drop is calculated by the following equations 1 and 2.

[0019]

[Equation 1] D ₁₅ = h ₁₀₀ −h ₁₅

[0020]

[Equation 2] D ₂₅ = h ₁₀₀ −h ₂₅

Here, D ₁₅ and D ₂₅ are 15 mm point and 25 m
Edge drop (μm) at m point, h ₁₀₀ , h ₁₅ , h ₂₅
Is 100 mm, 1 from the edge of the plate toward the center of the plate.
The plate thickness (μm) is a distance of 5 mm and 25 mm.

The edge drop prediction model is expressed by Equations 3 and 4
It is expressed by the structure shown in.

[0023]

(Equation 3)

[0024]

[Number 4] _{D 25 = a 25 · 1 *} P (HCW 1) + a 25 · 2 * P (HCW 2) + ... + a 25 · m * P (HCW m) + e 25

Here, HCW ₁ is HCW (m
_{m), a 15 · 1 ~a} 15 · n, a 25 · 1 ~a
_{25. m} is the influence coefficient, and e _{15 to} e ₅₀ are the influence terms of various rolling conditions such as the edge drop of the original plate, the material, the radius of the tapered portion, the rolling load and the plate radiation. The n and m are determined by selecting a stand that has a large influence on the edge drop of each point by the HCW. P () represents an arbitrary calculation process.

In this embodiment, an example in which the edge drop prediction model is set to the following equations 5 and 6 will be described.

[0027]

[Equation 5] D_Fifteen= A_{15 ・ 1}* HCW₁ ²+ A_{15 ・ 2}* HCW₂ ²+ A_15/3* HCW₃ ²  + C_Fifteen* Г_Fifteen+ E_Fifteen

[0028]

[6] _{D 25 = a 25 · 1 *} HCW 1 2 + a 25 · 2 * HCW 2 2 + a 25 · 3 * HCW 3 2 + C 25 * Г 15 + e 25

Here, Γ ₁₅ and Γ ₂₅ represent edge drops (μm) at 15 mm points and 25 mm points of the original plate, and C ₁₅ and C ₂₅ represent influence coefficients.

2 and 3 show examples in which the estimations by the equations 5 and 6 and the actual values are compared. It can be seen that Equations 5 and 6 accurately represent the edge drop.

Next, a method for setting the manipulated variable for edge drop control in strip rolling by a multi-pass multiple rolling mill will be described. This method sets the work roll shift amount so that the edge drop estimation value on the exit side of the final pass rolling mill by the edge drop prediction model falls within the target range, but in this embodiment, the number of edge drop prediction models is set. 5,
Since it is given by Equation 6 and the edge drop at the 15 mm point and the edge drop at the 25 mm point are respectively predicted, the work roll shift amount of the rolling mill from the first pass to the third pass so that the edge drop estimated values of these two points fall within the target range. An example of setting will be described.

The target upper limit values (μm) of the edge drop at the 15 mm point and the 25 mm point are defined by PDMAX ₁₅ and PD, respectively.
MAX _25, and the target edge drop lower limit values (μm) are PDMIN ₁₅ and PDMIN ₂₅ , respectively. 4, 5 and 6 show the procedure for obtaining the HCW. First, the edge drop estimation values D ₁₅ ^* , D ₂₅ ^* (μm) on the output side of the final path are obtained from the edge drop prediction models of Equations 5 and 6. At this time, HCW is an initial setting value (mm) given in advance.
To use.

Next, the edge drop target range TD for determining HCW ₁ is set using a fuzzy set. At this time, if the edge drop estimated value is larger than the edge drop upper limit value, that is, as shown in Equation 7,
Set it as the number 8.

[0034]

## EQU7 ## D _i ^* > PDMAX _i i = 15,25

[0035]

TD _i = Fuzzy [FMIN _i , FMAX _i ] = Fuzzy [PDMIN _i , (a _i.1 * PDMAX _i + (a _i.2 + a _i.3 ) * D _i ^* ) / (a _{i. 1} + a _i.2 + a _i.3 )] i = 15,25

Here, Fuzzy [a, b] represents a fuzzy set representing [approximately a or more and b or less], and FMIN _i (μ
m) is PDMIN _{i based on the} above edge drop target lower limit value.
And FMAX _i (μm) is the deviation (D _i ^* -PDMAX _i ) of the edge drop estimated value from the target upper limit value.
_Is divided according to the ratio of the influence coefficients a _i.1 , a _i.2 , a _i.3 to the edge drop of the HCW from the first pass to the third pass, and the deviation a _i.1 / (a _i.1 + a _i.2 + a _i.3 ) is 1
It is set in order to eliminate it by the work roll shift of the pass.

On the other hand, when the edge drop estimated value is smaller than the edge drop lower limit value, that is, in the case of the expression 9, the expression 10 is set for the same reason.

[0038]

## EQU9 ## D _i ^* <PDMIN _i i = 15,25

[0039]

TD _i = Fuzzy [FMIN _i , FMAX _i ] = Fuzzy [(a _i.1 * PDMIN _i + (a _i.2 + a _i.3 ) * D _i ^* / (a _i.1 + a _{i. 2} + a _i.3 ), PDMAX _i ] i = 15,25

If the edge drop estimated value is equal to or more than the edge drop lower limit value and equal to or less than the edge drop upper limit value, that is, as shown in the equation 11, the equation 12 is set.

[0041]

PDMIN _i ≦ D _i ^* ≦ PDMIN _i i = 15,25

[0042]

TD _i = Fuzzy [FMIN _i , FMAX _i ] = Fuzzy [PDMAX _i , PDMAX _i ] i = 15, 25

Next, for the configured edge drop target range by the number 8 or number 10 or number 12, obtaining the solution set of HCW ₁ by Equation 13.

[0044]

[Formula 13] HCW ₁ ⁱ = Fuzzy [HCW _{1, min} ⁱ , HC
W _{1, max} ⁱ ] i = 15, 25

Normally, the larger the W CH, the smaller the edge drop on the output side of the final path _{. mini} ⁱ is F
Obtained from MAX _i , HCW _{1. max} ⁱ is FMIN _i
Can be obtained from Specifically, in Equations 5 and 6, by substituting FMAX _i or FMIN _i for D ₁₅ and D ₂₅ , HC
It can be obtained by back-calculating W ₁ . HCW at this time
₂ and HCW ₃ use the default values.

From the solution set of Equation 13, 15 mm point and 25 m point
To satisfy the edge drop target range of m points, H
CW ₁ has to take a value in the range shown in the following Expression 14.

[0047]

[Equation 14]

Union {} represents a fuzzy set of intersections of fuzzy sets. H in consideration of stable operation
It is desirable that CW is as small as possible. HCW
Equation 15 is adopted as the set value of ₁ .

[0049]

(Equation 15)

However, if HCW ₁ ^F is an empty set, then H
The initial setting value of CW ₁ is used as it is. Where M
ax min {} represents the smallest element in the fuzzy set with the largest membership value. Ie HC
HCW with the highest membership value in W ₁ ^F
The minimum value among the above is adopted as HCW ₁ . Thus, the HCW for the first pass has been decided.

Next, let HCW _{1 be} the value obtained by the equation 15, and H
As CW ₂ and HCW _3, as initial setting values, estimated values D ₁₅ ^* and D ₂₅ ^* of the edge drop on the output side of the final path are obtained from the edge drop prediction models of Equations 5 and 6.

Next, the edge drop target range TD for determining HCW ₂ is set. Similar to the equations 7 and 8, the equation 17 is set in the case of the following equation 16.

[0053]

## EQU16 ## D _i ^* > PDMAX _i i = 15,25

[0054]

TD _i = Fuzzy [FMIN _i , FMAX _i ] = Fuzzy [PDMIN _i , (a _i.2 * PDMAX _i + a _i.3 * D _i ^* ) / (a _i.2 + a _i.3 )] i = 15,25

Here, FMAX _i (μm) is the deviation (D _i ^* -PDM) of the edge drop estimated value from the target upper limit value.
AX _i ) is divided according to the ratio of the influence coefficients a _i.2 and a _i.3 to the edge drop of the HCWs from the second pass to the third pass, and the deviation a _i.2 / (a _i.2 + a _i. It is set to eliminate ₃ ) by the work roll shift of the first pass.

On the other hand, similarly to the equations 9 and 10, the equation 19 is set in the case of the equation 18.

[0057]

[Equation 18] D _i ^* <PDMIN _i i = 15,25

[0058]

TD _i = Fuzzy [FMIN _i , FMAX _i ] = Fuzzy [(a _i.2 * PDMIN _i + a _i.3 * D _i ^* ) / (a _i.2 + a _i.3 ) _, PDMAX _i ] i = 15,25

Similar to the equations 11 and 12, the equation 21 is set in the case of the equation 20.

[0060]

[Number 20] ^{_{PDMIN i ≦ D i * ≦ PDMIN}} i i = 15,25

[0061]

TD _i = Fuzzy [FMIN _i , FMAX _i ] = Fuzzy [PDMAX _i , PDMAX _i ] i = 15,25

Next, the solution set of HCW ₂ is calculated as in the following expression 22 for the edge drop target range set in the expression 17 or the expression 19 or the expression 21.

[0063]

HCW ₂ ⁱ = Fuzzy [HCW _{2, min} ⁱ , HCW _{2, max} ⁱ )] i = 15, 25

Normally, the larger the HCW, the smaller the edge drop on the output side of the final path _{. min} ⁱ is calculated from FMAX _i , and HCW _{2. max} ⁱ is FMIN
It is obtained from _{i in} the same manner as in the case of Expression 13. HC at this time
W ₁ is a value determined by the number 15, HCW ₃ is the initial setting value. From the solution set of Equation 22, HCW _{2 to} satisfy all the edge drop target ranges of 15 mm point and 25 mm point
Must take a value in the range shown in the following equation 23.

[0065]

(Equation 23)

Then, as the set value of HCW _2, the equation 24 is adopted similarly to the equation 15.

[0067]

[Equation 24] HCW ₂ = Max min {HCW ₂ ^F }

However, if HCW ₂ ^F is an empty set, then H
The initial setting value of CW ₂ is used as it is. 2 above
The work roll shift amount of the pass is determined.

Next, the edge drop target range TD for determining HCW ₃ is set as shown in Expression 25.

[0070]

TD _i = Fuzzy [FMIN _i , FMAX _i ] = Fuzzy [PDMAX _i , PDMAX _i ] i = 15, 25

In the case of the third pass, since this is the last pass for setting the work roll shift amount, all deviations between the edge drop estimated value and the edge drop target upper and lower limits are eliminated by the work roll shift of the third pass. necessary. Therefore, the edge drop target range is uniformly determined as in Expression 25.

Next, the solution set of HCW ₃ for the edge drop target range of equation 25 is represented by equation 2 as in the case of equation 13.
Ask like 6.

[0073]

[Expression 26] HCW ₃ ⁱ = Fuzzy [HCW _{3, min} ⁱ , HCW _{3, max} ⁱ ] i = 15, 25

At this time, HCW ₁ is the value obtained by the equation 15, and HCW ₂ is the value obtained by the equation 24. From the solution set of Eq. 26, HCW ₃ must take the following values of Eq. 27 in order to satisfy all the edge drop target ranges of Eq.

[0075]

[Expression 27] HCW ₃ ^F = Union {HCW ₃ ⁱ } i = 15,25

Then, as the set value of HCW ₃ , Equation 28 is adopted.

[0077]

[Equation 28] HCW ₃ = Max min {HCW ₃ ^F }

However, in the case of the HCW ₃ ^F empty set, HC
The initial setting value of W ₃ is used as it is. With the above, the work roll shift amount of the third pass is determined.

By operating the work roll, the shape at the plate side end portion may become unstable. Therefore HC
The setting of W is from the 1st pass to the 3rd pass, and the shape (flatness) of the plate side end portion during this is determined by changing the setting of the work roll bender within the range where plate passing is possible or plate breaking does not occur. Although the deterioration of the shape is compensated, the setting range of the HCW is limited depending on the degree of the defective shape. Therefore, in the embodiment, the upper limit and the lower limit that can be set for each stand are set when calculating the HCW.

[0080]

As described above in detail, according to the present invention, in the edge drop control method in strip rolling, the HCW of each rolling mill is such that all edge drops of one or more points on the exit side of the final pass fall within the target range. Can be obtained and set and output without repeatedly calculating the edge drop estimation model, so that the following effects can be obtained. Highly accurate rolling can be reliably performed. Product yield is improved. Cost is reduced because the load on the computer is small. The product accuracy is kept high even with respect to the error of the edge drop estimation model.

[Brief description of drawings]

FIG. 1 is a drawing showing an example of a cold rolling mill in which the present invention is implemented.

FIG. 2 is an estimated value (D
₁₅ ) is a comparison diagram of the measured value (D ₁₅ ) and FIG.

FIG. 3 is an estimated value (D
₂₅ ) is a comparison diagram of the measured value (D ₂₅ ).

FIG. 4 is a diagram showing an HCW setting calculation procedure.

FIG. 5 is a diagram showing an HCW setting calculation procedure following FIG. 4;

FIG. 6 is a diagram showing an HCW setting calculation procedure following FIG. 5;

[Explanation of symbols]

 1 Steel plate 2 Work roll 3 Backup roll 4 Control computer and controller 5 Edge drop detector 6 Strip width detector 7 Multi-pass multiple rolling mill 8 Edge drop detector O point End point S point Start point

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G05B 13/04 8315-4E B21B 37/00 113Z

Claims (1)

(57) [Claims] 1. A method for edge-drop control of a plate using a multi-pass multi-rolling machine having a mechanism for shifting a work roll in which a roll cylinder end is tapered in a cylinder axis direction during plate rolling, A mathematical model of the edge drop of the rolled material expressed by a parameter including the work roll shift amount of each pass is created in advance, and the mathematical model is used to predict the edge drop on the exit side of one or more final-pass rolling mills. Then, the relative position of the work roll taper start point with the end of the width of the strip to be rolled is set sequentially from the upstream pass rolling mill so that they all fall within the target range set by the fuzzy set. Rolling edge drop control method.