JPH0159046B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a plate thickness control device for a one-stand multi-pass rolling mill.

[Technical background of the invention and its problems]

Conventionally, most of what is called a rolling mill is a one-stand, one-pass rolling mill in which one stand has one rolling pass.

In this type of rolling mill, the rolling reduction per stand is about 40% at most, and when performing high reduction rolling, a tandem rolling mill with a large number of stands arranged side by side is used.

Since this tandem rolling mill has a large number of stands, it requires a large installation area and is expensive.

In recent years, in order to keep the installation area and price low, three or more work rolls are stacked between the upper and lower backing rolls to form a large number of rolling passes.
One-stand multi-pass rolling mills that continuously pass the material to be rolled through these rolling passes are attracting attention.

According to this one-stand multi-pass rolling mill, it is possible to perform high-reduction rolling with a reduction rate of as much as 70% per stand. However, in this one-stand multi-pass rolling mill, when the target rolling position value is corrected for the purpose of controlling the sheet thickness on the exit side of the final pass, not only the sheet thickness on the exit side of the final pass but also the thickness of the first pass,
The thickness of the plate on the exit side of the second pass also changes. In other words, in a one-stand multi-pass rolling mill, there is mutual interference between passes, which leads to a decrease in plate thickness control accuracy. At present, there is no suitable plate thickness control device that takes this mutual interference between paths into consideration.

[Purpose of the invention]

The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a plate thickness control device for a one-stand multi-pass rolling mill that can satisfactorily control the plate thickness accuracy at the exit side of the final rolling pass.

[Summary of the invention]

In order to achieve the above object, the present invention includes an entry tension control system that controls the entry tension of the rolled material based on an entry tension target value, and an exit tension control system that controls the exit tension of the rolled material based on the exit tension target value. 1 comprising: an exit side tension control system that controls side tension; and a plate thickness control system that controls the amount of reduction of the rolled material based on the target value of the reduction position.
In the plate thickness control device of stand multi-pass rolling mill,
Input the reduction position target value correction amount ΔS output from the plate thickness control system, calculate the input side tension target value correction amount and the output side tension target value correction amount, respectively, and set the input side tension target value correction amount before the input side tension target value correction amount. The input/output side tension is added to the input side tension target value and output to the input side tension control system, and the output side tension target value correction amount is added to the output side tension target value and output to the said output side tension control system. The present invention is characterized by the provision of a target value correction amount calculation device.

[Embodiments of the invention]

The present invention will be described in detail below based on examples. The figure is a block diagram showing a one-stand multi-pass rolling mill to be controlled and the configuration of a plate thickness control device according to an embodiment of the present invention.

In the following description, a one-stand three-pass rolling mill will be taken up as an example of a one-stand multi-pass rolling mill, but the generality of the plate thickness control device to which the present invention is applied is not lost.

In the figure, numerals 1 to 4 are first to fourth work rolls, respectively, and these first to fourth work rolls 1 to 4 are stacked up in a manner that they are sandwiched between a lower backing roll 5 and an upper backing roll 6. The hydraulic lowering device 22
The rolling position is changed by .

The material to be rolled 11 is rolled as it passes between the work rolls 1 to 4 in a meandering manner in the direction indicated by the arrow. If rolling is performed three times per stand in this way, they will be called 1st pass, 2nd pass, and 3rd pass in order. 1st pass and 2nd pass
A pull-out roll 7 is installed between each pass, and a pull-out roll 8 is installed between the second pass and the third pass, and serves to pull out the rolled material 11 between each pass.

Note that when there is no need to pull out the material 11 to be rolled between each pass, rolling is performed in the state shown by the broken line.

Further, on the input side of the first pass, an unwinding reel 12 for unwinding the material 11 to be rolled and a tension meter roll 9 for pressure detection are installed, and on the exit side of the third pass, a tension meter roll 10 and a tension meter roll 9 for unrolling the material 11 to be rolled are installed. Material 1
A take-up reel 13 for winding up 1 is installed. Further, the rewind reel 12 has an electric motor 1.
An inlet tension control device 20 is connected to the take-up reel 13 via an electric motor 15, and an outlet tension control device 21 is provided to the take-up reel 13 via an electric motor 15, so that the inlet tension and the outlet tension can be controlled respectively. It's summery.

The deviation between the target rolling position value and the actual rolling amount is determined by the automatic rolling down control device 2 as the rolling position target value correction amount ΔS.
3 to the reduction device 22, and this correction amount ΔS
The amount of reduction is controlled by the reduction device 22 so as to eliminate this.

Regarding the configuration of the automatic plate thickness control device 23,
Since it is not directly related to this invention, its details will be omitted. Furthermore, the input/output side tension target value correction is performed by inputting the reduction position target value correction amount ΔS output from the automatic plate thickness control device 23 and outputting the input side tension target value correction amount ΔT _b1 and the output side tension target value correction amount ΔT _f3 . A quantity calculation device 24 is provided, the output of each of which is added to the input tension setting value T _b1 ^* and the output tension setting value T _f3 ^* , respectively, and input to the input tension control device 20 and the output tension control device 21. It is becoming more and more like this.

Here, the inlet tension control device 20 and the outlet tension control device 21 are current control devices 16 and 17, respectively.
and current target value calculation devices 18 and 19.

Next, the operation of this plate thickness control device will be explained. First, in order to control the exit side plate thickness to the target value in the final pass (third pass), the reduction position target value correction amount ΔS output from the automatic plate thickness control device 23 is input to the input/output side tension target value correction amount calculation device 24. be done.

The calculation device 24 calculates the entry side tension target value correction amount ΔT _b1 and the exit side tension target value correction amount ΔT _f3 using the following formula so as to offset the influence of the correction amount ΔS on the exit side plate thickness in the first pass and the second pass. ΔT _b1 = α・ΔS, α: Input side tension target value correction amount calculation coefficient ……(1) ΔT _f3 = β・ΔS, β: Output side tension target value correction amount calculation coefficient ……(2) Calculate.

Note that the arithmetic unit 24 can be configured to perform the above-mentioned functions using a minicomputer, a programmable controller, or the like. The calculated entry tension target value correction amount ΔT _b1 is the entry tension set value
It is added to T _b1 ^* , and becomes the entry side tension target value T _b1ref , which is sent to the entry side tension control device 20.

In this input side tension control device 20, the inputted input side tension target value T _b1ref is converted into a current target value I _PRREF by the current target value calculation device 18, and this current target value
I _PRREF is input to the current control device 16 to control the rotational torque of the rewind reel drive motor 14 to change the input tension.

Similarly, the output tension target value correction amount ΔT _f3 is added to the output tension set value ΔT _f3 ^* , and the output tension target value T _f3ref
Then, it is sent to the outlet tension control device 21. In the output side tension control device 21, similarly to the input side tension control device 20, a current control device 17 controls the take-up reel drive motor 15 to change the output side tension.

Note that the hydraulic lowering device 22 and the entry side tension control device 2
0, the crossing angular frequency between the outlet tension control device 21 is about 100 (rad/sec), and the above-mentioned 1,
It can be said that the response speeds of the rolling down device 22, the input side tension control device 20, and the output side tension control device 21, which are required to cancel the interference with the two-pass outlet side plate thickness, are almost matched.

Here, an example of a method for calculating the input side tension target value correction amount calculation coefficient α and the output side tension target value correction amount calculation coefficient β will be explained.

First, the amount of variation in plate thickness on the exit side of each pass Δh _j (j=1 to 3)
is expressed as a first-order polynomial of the reduction position target value correction amount ΔS, the input side tension target value correction amount ΔT _b1 , and the output side tension target value correction amount ΔT _f3 as shown in the following equations (3), (4), and (5). Formulate.

Δh ₃ =A ₁₁・ΔS+A ₁₂・ΔT _b1 +A ₁₃・ΔT _f3 ……(3) Δh ₂ =A ₂₁・ΔS+A ₂₂・ΔT _b1 +A ₂₃・ΔT _f3 ……(4) Δh ₁ =A ₃₁・ΔS+A ₃₂・ΔT _b1 +A ₃₃・ΔT _f3 ...(5) Here, A _ij , (i = 1 to 3, j = 1 to 3): constant (influence coefficient) Now, the reduction position target value correction amount ΔS is given. If ΔT _b1 = ΔT _f3 = 0, this correction of ΔS will cause Δh ₁ and Δh ₂ to become A ₃₁・
Only ΔS and _A21・ΔS will fluctuate. In a one-stand three-pass rolling mill as shown in the figure, variations in the thickness of the exit side of the first and second passes adversely affect the thickness of the exit side of the third pass due to mutual interference.

Therefore, it is desirable that the outgoing plate thickness variation Δh ₁ of the first pass and the outgoing plate thickness variation Δh ₂ of the second pass be as close to zero as possible. Therefore, here, assuming that Δh ₁ and Δh ₂ in formulas (4) and (5) are zero, A ₂₁・ΔS+A ₂₂・ΔT _b1 +A ₂₃・ΔT _f3 = 0 ...(6) A ₃₁・ΔS+A ₃₂・ΔT _b1 +A ₃₃・ΔT _f3 = 0 ...(7) Renewing equations (4) and (5) as in equations (6) and (7), this (6),
When formula (7) is combined to find ΔT _b1 and ΔT _f3 , ΔT _b1 = A ₂₃・A ₃₁ −A ₂₁・A ₃₃ /A ₂₂・A ₃₃ −A ₂₃・A ₃₂・ΔS
...(8) becomes. Therefore, it can be expressed as α=A ₂₃・A ₃₁ −A ₂₁・A ₃₃ /A ₂₂・A ₃₃ −A ₂₃・A ₃₂ ……(9). Further, ΔT _f3 becomes T _f3 =−1/A ₂₃ (A ₂₁ +A ₂₂・α)・ΔS (10). Note that the value previously obtained using equation (9) is substituted for α in equation (10). Therefore, β=-1/A ₂₃ (A ₂₁ +A ₂₂・α)...(11). In this way, the coefficients α and β used in the input/output side tension target value correction amount calculating device 24 shown in the figure can be calculated.

Next, an example of calculation using measurement data obtained from an experimental rolling mill will be shown. Here, set the target value of the reduction position to 0.01
If you want to increase it by mm, that is, assume that the reduction position target value correction amount ΔS=0.01. From the measured data, the relationships expressed by Equations (12), (13), and (14) were obtained as specific numerical examples corresponding to Equations (3), (4), and (5) above.

Δh ₃ =0.160・ΔS+2.93×10 ^-5・ΔT _b1 −5.25×10 ^-5・ΔT _f3 ...(12) Δh ₂ =0.256・ΔS+2.93×10 ^-5・ΔT _b1 +1.90×10 ^{- 5}・ΔT _f3 ……(13) Δh ₁ =0.392・ΔS−4.28×10 ^-5・ΔT _b1 +2.17×10 ⁻⁵・ΔT _f3 ……(14) This (12), (13), (14 ), ΔS=0.01mm, Δh ₂
= Δh ₁ =0 is substituted for Δh ₃ , ΔT _b1 , ΔT _f3
Δh ₃ +0.00316 (mm) ……(15) ΔT _b1 +106.70(Kgf) ……(16) ΔT _f3 +29.81(Kgf) ……(17) In other words, if the target roll position value is increased by 0.01mm for the purpose of reducing the thickness of the third pass outlet side, the target tension value on the inlet side will be 106.70 (Kg
f), and the output tension target value is 29.81 (Kg
If the thickness is increased by f), the variation in the thickness of the outlet side of the first pass and the second pass will be suppressed to almost zero, and only the thickness of the outlet side of the third pass will exceed 0.00316 mm.

〔Effect of the invention〕

As described above in detail based on the embodiments, in the present invention, when the target value of the reduction position is corrected using the hydraulic reduction device in order to control the final pass outlet side plate thickness to the target value, this correction is the first correction. Since the entrance tension target value and the exit tension target value are modified to offset the influence of the pass and the second pass on the exit side plate thickness, the final pass exit side plate thickness accuracy can be well controlled. It has the advantage of being possible.

[Brief explanation of drawings]

The figure is a block diagram showing the configuration of a one-stand multi-pass rolling mill to which the present invention is applied and a plate thickness control device according to an embodiment of the present invention. 11... Material to be rolled, 20... Entry side tension control device, 21... Output side tension control device, 22... Hydraulic rolling device, 23... Automatic plate thickness control device, 24... Input/output side tension target value correction Quantity calculation device.

Claims (1)

[Scope of Claims] 1. An entry tension control system that controls the entry tension of the rolled material based on a target entry tension value, and an exit tension control system that controls the exit tension of the rolled material based on the exit tension target value. In the plate thickness control device for a one-stand multi-pass rolling mill, the plate thickness control system includes an exit tension control system for controlling the rolling force of the plate, and a plate thickness control system for controlling the rolling amount of the rolled material based on a target rolling position value. Input the reduction position target value correction amount ΔS output from the thickness control system, calculate the input side tension target value correction amount and the output side tension target value correction amount, respectively, and adjust the input side tension target value correction amount to the input side tension target value correction amount. an input/output tension target value that is added to the tension target value and output to the input tension control system, and an input/output tension target value that is added to the output tension target value and output to the output tension control system; A plate thickness control device for a one-stand multi-pass rolling mill, characterized in that a correction amount calculation device is provided. 2 The input/output side tension target value correction amount calculation device calculates the input side tension target value correction amount ΔT _b1 and the output side tension target value correction amount ΔT _f3 using the following formula ΔT _b1 = α・ΔS α: Input side tension target value correction A plate thickness control device for a one-stand multi-pass rolling mill according to claim 1, wherein the calculation is performed using an amount calculation coefficient ΔT _f3 =β·ΔS β: an output side tension target value correction amount calculation coefficient.