JPS61238412A - Apparatus for determining set value of shape manipulated variable in rolling mill - Google Patents

Abstract

PURPOSE:To make the improvement in the quality of a product and stable operation possible by executing shape control with a specific key stand in accordance with the target plate crown ratio determined by calculation from rolling conditions such as plate thickness, width and rolling load. CONSTITUTION:The rolling conditions are inputted 1 and a model parameter is calculated 2. The max. plate crown ratio and min. plate crown ratio are calculated 3 from the model parameter, the rolling conditions and further the permissible range of the manipulated variable for the shape control and the permissible range of flatness. The target crown ratio is then determined 11 and in which stand or subsequent stands the specified plate crown ratio is possible is discriminated. The set value of the manipulated variable for the shape control is determined via such means. The skew angle, etc. of, for example, a skew roll rolling mill are used as the manipulated variable for the shape control Since the initial set value is automatically and easily determined in the above-mentioned manner, the improvement in the quality of the product an the stabilization of the operation are made possible.

Description

[Detailed Description of the Invention] [Industrial Applications] This invention provides a shape control operation in plate crown and flatness control of a continuous rolling mill or multi-pass rolling mill equipped with means for controlling the shape of a rolled material. [Prior art] This type of rolling mill is concerned with a device for determining the initial setting value of the quantity. It is important to keep the flatness between the buses within an acceptable range and to make υ as small as possible. To enable such shape control from the tip of the rolled material, it is necessary to initially set the shape control operation amount to an optimal value. In recent years, rolling mills with various shape control means have been proposed and put into practice, but in general, settings based on predetermined table values or settings by the operator have become mainstream, and it is difficult to respond to changes in rolling conditions. The current situation is that it is not easy to deal with this problem.

An example of an attempt at automation is the 859th Spring Lecture on Plastic Working (Naha, May 16-18, 1984), "Optimum Setting Control Method in Hot Strip Finishing Rolling (3) - Crown/Shape Control Setting - J (P33 ~P66).

This method uses the limit maximum plate crown and limit minimum plate crown that can be realized by each stand alone based on the flatness tolerance range and shape control operation amount tolerance range in each stand.
Calculate the maximum plate crown and minimum plate crown of each stand that can achieve the product target plate crown and product 1 target flatness,
The shape control operation amount is determined by using this intermediate value as the crown of each stand target plate.

[Problem that the invention seeks to solve]

According to the above conventional method, the plate crown co and flatness f0 on the entrance side of the first stand and the product target plate crown Cn and product target flatness fn on the exit side of the final stand are constrained, and the maximum plate crown and minimum plate Since the crown is calculated, complicated correction calculations are required after that calculation. In addition, by converting the maximum plate crown and minimum plate crown by this method into plate crown ratio, C6=Ofirm,
fo=0%, Cn”=50 a=T f n
The case where ``=0% (n=6) is shown in FIG. 3 by a dotted line 17.

This invention has been made with attention to this point, and it is an object of the present invention to provide a device that easily and automatically determines the optimum initial setting value of the shape control operation amount for any rolling condition. .

[Ninth way to solve the problem]

The maximum/minimum plate crown ratio calculation means according to the present invention is as follows:
Without restraining the product target plate crown C♂, the first
~Limiting condition (4) up to the i-th stand.

The maximum plate and minimum plate crown ratios of the first stand that can be achieved based on formula (5) are calculated from the first stand to the nth stand (
Based on the maximum and minimum plate crown ratios, the target plate crown ratio calculation means achieves the finished product target plate crown CK, the finished product target flatness f:, and the downstream The target plate crown ratio of each stand is determined so that the flatness between the stands is as small as possible in the stand, and the shape control operation amount determining means determines the set value of the shape control operation amount based on this target plate crown ratio. It is.

[Effect]

Before explaining the embodiments, the above-mentioned nine-plate crown, flatness, and shape control operation amount will be explained to help understand the present invention.
Furthermore, we will use a continuous rolling mill as an example to explain the model formula for determining the relationship between the strip crown ratio (the ratio of strip crown to strip thickness) and the method for determining the shape control operation amount, but the same applies to multi-pass rolling mills. be.

That is, the plate crown ratio K·, plate crown ci, and flatness fi on the exit side of the first stand of the continuous rolling mill are given by the following equations.

K1= (4/J (1)
= lkl (Xi) ・Ki −1+ ILi (P
i, CRi, Xi) (2) fH=b p (
Ki−Kl−1+ b□” fi−x ) (3
) However, in the above formulas (1) to (3), i is the stand number (l = 1 to n, H = final stand number), h is the outlet side plate thickness, X is the shape control operation amount, P is the rolling load, CB is the roll crown, the akr a tit plate crown ratio influence function, and b and bf are the flatness influence coefficients. Note that ak is a function of the model parameters determined by the rolling conditions such as sheet width and roll dimension, and the shape control operation amount X, and a is the model parameter determined by the above rolling conditions and the rolling conditions, that is, the model parameter for equation (2). Pe CRs and shape control operation amount
b, b(F'i) are model parameters determined by rolling conditions such as plate thickness, plate width, and roll dimension.

Therefore, if the above rolling conditions, the entrance plate crown Co of the continuous rolling mill, and the input side flatness f are given, the plate crown ratio Kit plate round Cie flatness f1 on the exit side of each stand
are (1) to (3) as a function of only the shape control manipulated variable x1.
) can be obtained from the formula. Conversely, once the plate crown ratio Ki is determined, the shape control operation amount x1 can be determined from equation (2).

The purpose of this invention is to calculate plate thickness, plate width, rolling load, roll crown and continuous rolling mill entrance side plate crown co, entrance side flatness f, etc. using the above-mentioned equations (1) to (3) as basic equations. By giving the rolling conditions, the product target plate crown CM and the product target flatness f♂ are secured, and the first to (n-1)th
The flatness of the stand exit side, that is, the flatness between the stands (~f
This is intended to obtain a shape control operation amount x1 that is within the n-1e allowable range.

For the above purpose, first, a method for determining the shape control operation amount Xl will be described in detail below.

First, input the rolling conditions such as plate thickness, plate width, rolling load, roll crown, etc., and second, enter (2) above.

Model parameters regarding plate crown ratio influence functions ak, & and flatness influence coefficients S, J in equation (3) are calculated.

Thirdly, the maximum plate crown ratio that can be achieved under the allowable range of shape control operation amount and allowable flatness range given by the following equations (4) to (5), m1″8. and the minimum plate clarification, m
The in' ratio K is calculated sequentially starting from the first stand.

Xl<Xi<11(4n, U L fi<;fl≦f1,'n='n min
(5) That is, on the right side of equations (2) and (3) above.

Kl-,=1-1"", 6"=Ko=Co/ho
(6) t 1-12fi-1, to = to
Considering (7)-, the maximum plate crown ratio K
Calculate smILX as follows. Note that the minimum plate crown ratio K1m1n can also be calculated in the same manner by replacing max with min, so a description thereof will be omitted.

First, by setting 1 to the maximum value of the plate crown ratio regarding the limit of the shape control operation amount, and considering the equation (4) to the equation (2), calculate the following equation (8). Nao, (8) formula vCsp itez
, maX1 is xio at which Ki becomes maximum, or the lower limit xiL, or the upper limit xiU. (In other words, ximtxt is the xio value that maximizes Ki within the limit set by equation (4), 9Kimaxi=,ki(x,
maXl) * Ki −t”x−+′ i (Pi,
CRi-“i”! ”) Also, the maximum value of the plate crown ratio regarding the flatness limit is mJLX2 @, (3) 2K
(5) Formula? It is calculated using the following equation (9).

K, maX2 = 1iU/b, + K, -, maX-
bf, , f, -, tnaX (g) Next, by setting 1 to the maximum plate crown ratio as the minimum value of 1 above and KimaX2, it is determined by the following formula (2).

K, rfla! == ml, (K, m1LX1,
K, m1LX2) (,,)'t7'?
, Kim & xfr: above, the flatness to the maximum plate crown ratio is 1. maX is determined from equation (3) using equation C1 below.

f, m&X=1. , , , (K, mJLX-K,
-1 m1 In the ratio, maX (1=1~n
) can be calculated. Similarly, to the minimum plate crown ratio, m
in (t = 1 to n) can also be calculated.

Fourth, the target plate crown ratio Ki'' is the maximum plate crown ratio K tm″8 calculated above and the minimum plate crown ratio H
Considering the limitations of K, min and the fact that fi-□ has a small effect on fi, the flatness fi should be as small as possible at the downstream stand, that is, as much as possible as can be seen from equation (3). Calculate as follows so that the stand has a constant plate crown ratio (Ki = Ki - □). − First, the target plate crown ratio Xn* (X♂=C♂/
hn) Find the most downstream stand k that does not satisfy InIn <Kn"< Kim & )Kt””), max(
t: ni < x, min)) Next, to find the target plate crown ratio x, 4k, the above key stand is k (n - 1, k = n - 1, ni = n The processing is divided depending on the case.

That is, k (Ki for n -1) "Kim&"(1<i<k):Kn"
) Kkrn&” Oto@==ni, im'n (1<K
;k) : Kn” (Kknl” Otlk=[c
(k+1≦1(n-1) =♂ (1=n) (to) Kc in the above equation (2) is a constant value, and the above (2).

In equation (3), where t=~n, Kk=Kkrn
1yc, fk=fkm88(Ki)Kl-” (D (
! :'f! )Kk=Kkm1'r', fk=fkm
'n (Kn<Kkm1nnotki)Kn==Kn'',
fn==f; 1=Kc (i=+1 to n-1)
Kc can be calculated by considering α◆ (note that this Kc
This will be referred to as t constant plate crown ratio. )ktomi-
1, K11I=K1”!('L=1~k): Kn
> When Kk”” = Ki”” (i = 1~k
): K, "(Kk"" (D (!: IJ=ni," (1=n) (to)k
= If n, then Kl"=Kirn1x (1=1~n); to:>KkIl
n&8notki=x, (i=t~n):ni:(Kk
”1n(D(!:l!in α peak, that is, in this case, it is not possible to secure the target board crown ratio of the finished product, so Ki should be set to Knm- or K
Change to nmin. Note that this change value can be expressed as Kmin (
The fact that Ki<KnnllLX becomes Kn4' is also q
ita, and in this case, the above (to) expression or (to)
1 can be calculated using the formula.

Fifth, the above formula (b) or #'i (to) formula or a
Calculated using the Q formula, the tiger mouth mark crown ratio Kl” (i=1~
By substituting n) into equation (2) and solving this with respect to xl, the shape control operation amount Xi that achieves the object of the present invention can be calculated as shown in the following equation.

x1=gi(Ki-K1-1", Pi, CR
i) ``[Embodiment of the invention] This BA related to the device for determining the optimal metal shape control operation amount for any rolling conditions described above is applied to a six-stand continuous pressure system having shape control means in the first to sixth stands. The following is a description of the ninth embodiment applied to the occasion.

In the K1 diagram, reference numeral 1 indicates a rolling condition input means for inputting rolling conditions such as plate thickness, plate width, rolling load, and roll crown; A model parameter calculation means for calculating model parameters of the flatness model; 6 a maximum/minimum plate crown calculation means for calculating a maximum plate crown ratio and a minimum plate crown ratio; 4 a target plate crown ratio determination unit for determining a target plate crown ratio The means 5 is a shape control operation amount determining means that calculates and determines the set value of the shape control operation amount. The target board/round ratio determining means 4Vi is comprised of means 6 to 12 enclosed by broken lines, and 6 is the ninth key stand number for determining from which stand onwards a constant board crown ratio is possible. 7 is a determining means for determining the target plate crown ratio calculation means based on the key stand number; 8 is a constant plate crown ratio calculating means for calculating the constant plate crown ratio; 9 is the total target plate crown ratio for the finished product; Product target board crown ratio changing means to be changed, 10
11 and 12 are target plate crown calculation means for calculating the target plate crown ratio.

The device for determining the set value of the shape control operation amount for a rolling mill according to the present invention is constituted by the above-mentioned means, in which the rolling conditions are input in the means 1, and the means 2 calculates the above (2) based on the rolling conditions. ), calculate the model parameters of equation (3).

Next, the model parameters calculated by means 6i and the above rolling conditions (rolling load, roll crown) and the above (4),
Using the allowable range of shape control operation amount and allowable flatness range determined by equation (5), the maximum plate crown ratio K, m & Calculate K 1m1 n. Next, the means 4 determines the target plate crown ratio to be 1'' within the limited range of [1nllX and K1m1m calculated above.

That is, first, the means 6 is the product target plate crown ratio Kn''
and the above-calculated Ki"" j Kim" (according to the size relationship of D, calculate the key stand number k for determining from which stand a constant plate crown ratio is possible, and use means 7 to determine the value of this k. If k(5, means 8, k=
5, means 11f:, if k=6, means 9 is activated. Means 8 calculates the constant plate round ratio Kc using the α◆ formula,
Means 1o is this Kc and the target curvature crown ratio Kn4)
, and in the above calculation, ml! Alternatively, using Ktmin, the target plate crown ratio x, 4k is calculated by the above equation (2).
Calculate. Alternatively, the means 11 is the target plate crown ratio K
i+ is calculated using the formula (g) above. Alternatively, the means 9 changes the finished product target plate crown ratio lx♂ to the above-calculated Knmlx or Knmln, and the means 12 changes the target plate crown ratio Kl'' to the α-formula for achieving this changed target plate crown ratio. Finally, the means 5 calculates the ninth shape control operation amount Xi that achieves - to the target plate crown ratio determined by the means 4 (that is, the means 10 or 11 or 12) K.
Calculate using the formula and use this as the shape control operation amount setting value.

Note that in the above Xi, the suffix l is 1 to 6.

FIG. 2 shows the results of the shape control operation amount set in the shape control operation amount setting value determining device of the present invention when the skew angle (horizontal angle formed by the upper and lower work rolls) of the skinny roll rolling mill is used. 2B shows the flatness, and FIG. 2C shows the target plate crown ratio. In the figure, the dotted line 13 indicates the finished product target plate crown CI”
= 50 μrlL (When the finished plate thickness hs = 2.34 m, the target plate crown ratio of the finished product is 41 = 2.14%) The broken line 14 is cs” = 80 μWL (ν = A42qb), and the dashed line 15 is C@” = 100 μm (K@”=4.27%)
The graph shows the stand transition of the skew angle, flatness, and plate crown ratio (i.e., target plate crown ratio) in the case of . Second
In the figure, when the one-dot line 13 (C-=50μ) indicates the finished product target plate crown CI is secured and the key stand number is 2.

By keeping the plate crown ratio of the 3rd to tX5 stands constant, the flatness is reduced in the later stands.

Moreover, when broken line 14 (cs''=soμ), the finished product target plate crown C: is secured, and the key stand number is 4, so the flatness on the exit side of the fifth stand is made small.

Furthermore, when the dashed line 15 (C" = 100 μn drop), the key stand number becomes 6, and the target plate crown C- cannot be secured, so Ca" == 86.7 μn (K
g" = 3.71%, ma" = 3.71%). It goes without saying that the stand transition of the target plate crown ratio at this time is the same as the transition of the maximum plate crown ratio.

In any of the above cases, the target flatness of the finished product V t:= O%
is ensured, and the skew angle tolerance is -0.2%.
satisfies fi≦0.2ch (l=1 to 5).

1+, the maximum plate crown ratio and minimum plate crown ratio due to the maximum plate obtained by means 6 in FIG. 3 depend on the product target plate crown C, 4) and the product target flatness f6',
The present invention does not rely on this. That is, the maximum and minimum plate crown ratios of the present invention and the conventional method have different definitions.

In addition, in the embodiment mentioned above, the case was described in which the first to sixth stands had shape control means. However, in the case where any stand has a shape control means, both the upper and lower limit values xlU and xiL of the allowable range of shape control operation amount in equation (4) may be set to 0 for a stand without a shape control means.

9. In the above-described embodiment, the roll crown is input as the rolling condition, but even if the roll crown is calculated based on the rolling conditions such as rolling load and rolling time, it departs from the essence of the present invention. It's not a thing.

Furthermore, in the above-mentioned implementation results, the case where the shape control operation amount is the skew angle of a skew roll rolling mill, but the shape control operation amount is also applicable to objects whose shape can be changed, such as a pending roller or an intermediate roll shift amount of a 6-high mill. Needless to say, anything is fine.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to automatically and easily determine the optimum initial setting value of the shape control operation amount for any rolling condition.

Furthermore, according to the present invention, the erf function not only ensures the product target values for plate crown and flatness immediately after the start of rolling, but also rolls to keep the flatness between stands or buses as small as possible within the allowable range. This has the effect of greatly contributing to improved product quality and stable operations.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating one embodiment of the present invention. FIG. 2 is a diagram showing the results of implementation of this invention.
Figure A shows the skew angle, Figure 2B shows the flatness, and Figure 2C shows the target plate crown ratio. FIG. 6 is a graph comparing the maximum and minimum plate crown ratios according to the present invention and the conventional example. In the figure, 2 is a model parameter calculation means, 6 is a maximum/minimum sheet crown ratio calculation means, 4 is a target sheet crown ratio determination means, and 5 is a shape control operation amount determination means.

Claims (3)

[Claims] (1) In a continuous rolling mill having shape control means for plate crown and flatness control of the rolling mill, a rolling condition input means for inputting rolling conditions such as plate thickness, plate width, rolling load, etc.; and the rolling condition input means. model parameter calculating means for calculating parameters of the plate crown and flatness model in response to an output from the means; and for calculating a maximum plate crown ratio and a minimum plate crown ratio in response to the output from the model parameter calculation means. maximum/minimum plate crown ratio calculating means; target plate crown ratio determining means for determining a target plate crown ratio in response to the output from the maximum/minimum plate crown ratio calculating means; and said target plate crown ratio determining means. A shape control operation amount determining device for determining a shape control operation amount setting value in a rolling mill, comprising: a shape control operation amount determining means for determining a shape control operation amount setting value in response to an output from the rolling mill. (2) In claim (1), the target plate crown ratio determining means receives the output from the maximum/minimum plate crown ratio calculating means and determines in which stand a constant plate crown ratio is possible. a keystand calculation means for calculating a keystand number for a keystand, a determination means for determining this keystand, and a constant plate crown ratio calculation for calculating a constant plate crown ratio activated by the determination result by the determination means. 1. An apparatus comprising: a means for changing a target plate crown ratio of a finished product; and a target plate crown ratio calculating means. (3) The apparatus according to claim (2), wherein the continuous rolling mill is a multi-pass rolling mill, and the key stand calculation means calculates a key pass number.