JPS6146311A - Sheet thickness control device of single stand multi-pass rolling mill - Google Patents

Abstract

PURPOSE:To control well the accuracy of sheet-thickness at the outlet side of a final rolling pass by inputting the correcting quantity of a rolling-down position target- value, outputted from a sheet-thickness control system, and calculating the correcting quantities of tension target-value at the inlet and outlet sides respsectively. CONSTITUTION:A correcting quantity DELTAS of rolling-dowon-position target-value, outputted from an automatic sheet-thickness control unit 23, is inputted to an inlet-outlet-side tension-target-value correcting-quantity arithmetic unit 24, and said correcting quantities are calculated so that the correcting quantity DELTAS offsets the effects on the outlet- side sheet-thicknesses of the 1st and 2nd passes to each other. The calculated correcting quantity is added to an inlet-side-tension target-value, and the result is sent to an inlet-side tension control unit 20 as a inlet-side-tension target-value. The tension target- value is converted into a current target-value by the unit 20 and is inputted to a current control unit 16, to change the inlet tension by controlling the rotating torque of an unwinding-reel driving motor 14. In the same manner, the outlet-tension target-value correcting quantity is added to a set tension-value and the result is sent to an outlet- tension control unit 21, and the outlet tension is changed by controlling a winding-reel driving motor 15.

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, what is called a rolling mill has one stand per stand.
Most of the mills were one-stand, one-pass rolling mills with two rolling passes.

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, with the aim of keeping 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, and the material to be rolled is continuously passed through these rolling passes. One-stand multi-pass rolling mills 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 The thickness of the exit side of the pass will also change. 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 still no suitable plate thickness side t11 device that takes into account this mutual interference between each path.

[Purpose of the invention]

This invention has been made in consideration of the above-mentioned circumstances, and its purpose 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. be.

(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 the entry tension target value, and an entry tension control system that controls the entry tension of the rolled material based on the exit tension target value. A one-stand multi-pass rolling mill comprising: an exit tension control system that controls the exit tension of the rolled material; and a plate thickness control system that controls the reduction m of the rolled material based on a target reduction position value. In the plate thickness control device, the reduction position target value correction amount ΔS output from the plate thickness control system is input, and the input side tension target value correction amount and the output side tension target value correction amount are respectively calculated. The input-side tension target value correction amount is added to the input-side tension target value and outputted 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 output side tension control system. It is characterized by being provided with an input/output side tension target value correction amount calculation device that outputs to the tension control system.

[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 explanation, a 1-stand 3-pass rolling mill will be taken as an example of a 1-stand multi-pass rolling mill.
This does not mean that the generality of the plate thickness control device to which the present invention is applied is lost.

In the figure, 1 to 4 are the first to M4 work rolls, respectively.
These first to fourth work rolls 1 to 4 are arranged in a stacked manner sandwiched between a lower backing roll 5 and an upper backing roll 6, and the rolling down position is changed by a hydraulic rolling down device 22. .

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 J3 rolling is performed three times per stand in this way, they will be called 1st pass, 2nd pass, and 3rd pass in order. A drawer roll 7 is provided between the first pass and the second pass.
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 first pass side there are a rewinding reel 12 for unwinding the material 11 to be rolled and a tension meter roll 9 for pressure detection, and on the third pass exit side there is also a tension meter roll 10 and a tension meter roll 12 for unwinding the material 11 to be rolled. 11 is installed. Further, an inlet tension control device 20 is connected to the rewinding reel 12 via an electric motor 14.
On the other hand, the take-up reel 13 is provided with an outlet tension control device 21 via an electric motor 115, and is configured to control the inlet tension and the outlet tension, respectively.

The deviation between the target rolling position value and the actual rolling amount is given as the rolling position target value correction amount ΔS from the automatic rolling control m device 23 to the rolling device 22, and the rolling device 22 adjusts the rolling ffi to eliminate this correction amount ΔS. #lControlled.

Note that the configuration of the automatic plate thickness control device 23 is not directly related to the present invention, so the details thereof will be omitted. Furthermore, the input side tension target value correction amount Δ”b is inputted with the reduction position target value correction amount ΔS output from the automatic plate thickness control device v:123.
An input/output side tension target value correction amount calculating device 24 is provided which outputs an input/output side tension target value correction amount ΔTf3 and an input/output side tension target value correction amount ΔTf3. They are each added and input to the inlet tension control device 20 and the outlet tension control device 21.

Here, the input side tension control device V! 120 and the outlet tension control device 21 each include a current control device @16.17 and a current target value calculation device 18.19.

Next, the operation of this plate thickness control device will be explained.

First, in the final pass (third pass), in order to control the exit side plate thickness to the target value, the rolling position target value correction amount ΔS output from the automatic plate thickness control device 23 is calculated by the input/output side tension target value correction amount calculation device 2.
4 is input.

The arithmetic unit 24 calculates the entry tension set value correction value ΔTb1 and the output tension target value correction amount ΔTf3 using the following formula so that the correction amount ΔS cancels out J[) which affects the exit side plate thickness in the first pass and the second pass. Calculate using the % formula %.

Note that the arithmetic unit 24 is a minicomputer, a programmable controller, or the like, and can perform the above-mentioned functions.
It can be configured as follows. Calculated input side tension target value; I positive amount ΔTb1 is input side tension set value Tbi”
is added to the input side tension target value "blref", which is sent to the input side tension control system 20.

In this input side tension control device 20, the inputted input side tension target value T is converted into a current target value I by 1ref to the Ti flow target value calculation device 18, and this current value RRE
F target value I is input to current control wJ device 16 and winding RR
EF The rotational torque of the return reel drive motor 1114 is controlled to change the entry tension.

Similarly, the output tension target value correction amount Δ”f3 is added to the output tension set value T, 3* to become the output tension target value T and is sent to the output tension control device 121.

3rer In this output side tension control device 21, a current control device @17 is operated similarly to the input side tension control device 20.
is controlled to change the exit tension.

Note that the intersection angular frequency between the hydraulic pressure lowering device 22, the inlet tension control device 20, and the outlet tension control device @21 are all 100 (
rad/sec), and the rolling down device 2 required to offset the interference with the 1° 2 pass outlet side plate thickness mentioned above.
2. Inlet tension control device @20 and outlet tension control device 21
It can be said that the matching of response speed is almost achieved.

Here, an example of a method of calculating the input side tension target value correction amount calculation coefficient α and the calculation coefficient β for the output side tension target value correction F1 will be explained.

First, for each pass, the outlet side plate thickness variation mΔhj (j-1 to 3) is the reduction position target value, the correction amount ΔS, and the input side tension target value correction amount Δ”
The following formulas (3), (4), and (5) are formulated as a first-order polynomial between bl and the output side tension target value correction amount ΔTf3.

Δh −A ・ΔS+A12・Δ”b1+A13・
ΔTr3 ・・・・・・(3) Δh −A
・ΔS+A22・ΔTb1・221 +A23・ΔTr3 ・・・・・・(4)Δ
h-A31°ΔS+A32°ΔTb1+A33・ΔTf
3 ・・・・・・(5) Here, A I J
, (i-1~3.j-1~3): Constant (influence coefficient) Now, assuming that the reduction position target value correction amount ΔS is given,
If ΔTb1-ΔT remains 3-0, Δh1 and Δh2 will change by A31·ΔS and A21·ΔS, respectively, due to the correction of ΔS. Not shown J: Eel 1
In stand three-pass rolling C1, due to mutual interference, variations in the exit side plate thickness in the M1 pass and the second pass also have an adverse effect on the exit side plate thickness in the third pass.

Therefore, it is desirable that the outgoing plate thickness variation mΔh1 of the first pass and the outgoing plate thickness variation amount Δh2 of the second pass be as close to zero as possible. Therefore, here is (4).

(5) Setting Δh and Δh2 in the formula to zero, A ・ΔS+
A22・ΔTb1+A23・ΔT f3-0...
...... (6) A31・ΔS+A32・ΔTb1+A33・ΔTf3−
0・・・・・・・・・・・・ (7) Rewrite equations (4) and (5) as in equations (6) and (7),
If we combine these equations (6) and (7) and find ΔTbi and Δ”f3, we get ・・・・・・・・・・−(8). Therefore, Ha22°A33 '23°Ha32 Also, Δdf3 becomes... (10).In addition, the value obtained earlier in equation (9) is substituted for α in equation (10).Therefore, it is as follows. It is possible to calculate the coefficients α and β used in the input/output side tension target value correction foot calculating device 24 shown in the figure.

Next, calculation examples using measurement data obtained from a practical rolling mill are not shown. Here, if you want to increase the target rolling position value by 0.01N+, that is, rolling down.

Assume that the position target value correction amount Δs-o, oi. (12) and (13) are specific numerical examples corresponding to the above formulas (3), (4), and (5) based on the measured data.

The relationship expressed by equation (14) was obtained.

Δh3-0.160・ΔS+2.93 ×10-5・ΔTb1-5.25×10 ・ΔTf3 ・・・・・・(12)Δ
h2-0.256・ΔS+2.93 X10'・ΔTb, +1.90 ×10・ΔTf3 ・・・・・・(13)Δ
h1=0.392・ΔS−4.28×10−5・ΔTb1+2.17×10・ΔTf3 (14) Add ΔS−0, 01a
++, Δh2-Δh1-0 respectively to obtain Δh3.
ΔTb1. When ΔTf3 is calculated, Δh 3+ O
, OO316 (shoes) ...... (15) ΔTb1+
106.70 (kgr) ・・・・・・(16
)ΔT f3 +29. 81 (kaf
n...----(17 n. That is, the third
When the rolling position target value is increased by 0.01 #II for the purpose of reducing the pass outlet side plate thickness, the input side tension target value is increased by 106, 70 < kQf ),
If the exit tension target value is increased by 29.81 (kaf), the fluctuations in the exit plate thickness in the first and second passes can be suppressed to almost zero, and only the third pass exit plate thickness will exceed 0.00316 twt. become.

〔Effect of the invention〕

As described above in detail based on the embodiments, in this invention, when correcting the target value of the reduction position in order to control the final pass exit side plate thickness to the target value using the hydraulic reduction device,
The entrance tension target value and the exit tension target value are modified to offset the influence of this modification on the exit side plate thickness in the first and second passes, resulting in good final pass exit side plate thickness accuracy. It has the advantage of being able to be controlled.

[Brief explanation of the drawing]

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... Entrance side tension control device,
21... Output side tension horn control device, 22... Hydraulic lowering device, 23... Automatic plate thickness control 611 equipment U, 24... Input/output side tension target value correction amount calculation device.

Claims (1)

[Scope of Claims] 1. An entry tension control system that controls the entry tension of the rolled material based on the entry tension target value, and an entry 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, and a plate thickness control system for controlling the rolling reduction amount of the rolled material based on the rolling position target value. 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 calculate the input side tension target value correction amount by the input side tension target value correction amount. an input/output side tension target that is added to the side tension target value and output to the input side tension control system; and an input/output side tension target that is added to the output side tension target value and output to the output side tension control system. A plate thickness control device for a one-stand multi-pass rolling mill, characterized in that a value 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_b_1 and the output side tension target value correction amount Δ
Claim 1, characterized in that T_f_3 is calculated by the following formula ΔT_b_1=α・ΔSα: input side tension target value correction amount calculation coefficient ΔT_f_3=β・ΔSβ: output side tension target value correction amount calculation coefficient Plate thickness control device for one-stand multi-pass rolling mill.