JPS59218209A - Device for controlling sheet thickness in single-stand multipass rolling mill - Google Patents

Abstract

PURPOSE:To improve the accuracy of sheet thickness by obtaining the deviation between an estimated value of sheet thickness at the outlet of a rolling pass and a target value of sheet thickness at the outlet and installing, by the number of rolling passes, devices for computing each the correcting quantity of a set value of an increase- bender-pressure between upper and lower work rolls. CONSTITUTION:A delay device 20 outputs an estimated value HIM of sheet thickness at the outlet of the 1st pass, obtained by using the generated number of pulses N1, to an arithmetic device 21 for computing the 1st-pass mass-flow sheet thickness, by delaying, by a prescribed time, the sheet thickness HIX detected by a thickness gauge located at the inlet side. The device 21 computes an estimated value hIM of the sheet thickness at the outlet of the 1st pass to give it to a delay device 22. In the same way, an arithmetic device 25 for the 3rd-pass mass-flow sheet thickness computes an estimated value h2M of sheet thickness at the outlet of the 3rd pass. Further, the estimated values hIM, hZM, h3M of the sheet thicknesses at the outlets of respective passes the 1st, 2nd, 3rd are given to respective, the 1st - the 3rd pass mass-flow automatic gain- controlling devices (AGC) 26, 27, 28, to correctingly control the increase-bender-pressures between the upper and lower work rolls of the 1st pass - the 3rd pass thereby controlling separately the sheet thickness at the outlet of each pass.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a multi-stand rolling mill that rolls a material to be rolled by stacking at least three or more work rolls and passing the material to be rolled continuously between each of the work rolls. -Relating to a plate thickness control device in a ZESS rolling mill.

[Technical background of the invention]

Conventionally, general rolling mills have been configured for one-stand, one-noses rolling. However, in this type of rolling mill, the reduction rate per stand is about 40% at most, so in tandem rolling mills, it is necessary to increase the number of stands to achieve high reduction rolling, which increases cost and space. someone said.

However, recently, attention has been paid to L-stand multi-pass rolling mills aimed at saving cost and saving space.

This is a method that enables stand multi-pass rolling by installing three or more work rolls, whereas there were only two in the past, and passing two rolls of material through each of the adjacent work rolls. -17105 (Japanese Patent Application No. Sho M-91478). This type of one-stand multi-pass rolling mill has the advantage that (1) it is possible to perform high reduction rolling with a rolling reduction ratio of 70% per stand.

[Problems with background technology]

However, the current situation is that no effective control device has yet been found for automatic plate thickness control in this type of l-stand multi-pass rolling.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a plate thickness control device for obtaining material having good plate thickness accuracy at the exit side of the final bus of an L-stand multi-pass rolling mill. purpose.

[Summary of the invention]

In order to achieve the above object, the present invention includes a thickness gauge that detects the thickness of the rolled material before rolling, and a plurality of speed detectors that detect the running speed of the rolled material on the entry and exit sides of each rolling pass. At the same time, the running time of the material to be rolled on the inlet side of the rolling bus is determined based on the detection signal of the speed detector installed on the inlet side of the rolling bus, and the running time of the material to be rolled at the inlet side of the rolling bus is determined by the detection signal of the thickness gauge or the rolling process described later. a delay device that delays a bus exit side plate thickness prediction value signal and outputs it as a rolling bus entrance side plate thickness prediction value; A predicted value calculating device for calculating a predicted value of plate thickness on the exit side of the rolling bus, and an increase 4 between the upper and lower work rolls of the rolling pass for determining the deviation value between the output value of this predicted value calculating device and the target value of the plate thickness on the outlet side of the rolling pass. The plate thickness control device is configured by providing the same number of correction amount calculation devices for calculating the correction amount of the under pressure setting value as the number of rolling passes.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention shown in FIGS. 1 to 3 will be described.

FIG. 1 is a side view of an l-stand multi-pass rolling mill to be controlled by the present invention, and FIG. 2 is a front view of FIG. 1. In addition,
For convenience of explanation, an L-stand three-pass rolling mill will be described below, but it goes without saying that the present invention is also applicable to rolling mills with four or more passes.

In FIG. 1, 1. Second. Four work rolls, third and fourth work rolls 1, 2, 3.4, are connected to a lower backing roll 5.
The material to be rolled (hereinafter referred to as "-material") A passes between each work roll in the direction shown by the arrow. For convenience of explanation hereinafter, the rolling pass performed between the first and second work rolls 1.2 will be referred to as the first pass, and the rolling pass ' performed between the second and third work rolls 2 and 3 will be referred to as the first pass. The rolling pass performed between the third and fourth work rolls 3 and 4 will be referred to as the third pass (or final pass). 1.Drawer roll 7 between 2nd pass
, between the second pass and the third pass, a pull-out roll 8 is provided between the second and third passes. In addition, when there is no need to draw out the material between each pass, the first and second drawing rolls 7.8 move and roll the material in the state shown by the broken line in FIG. 1. An entry side material speed detection roll 9 is provided on the entry side of the first pass, and an exit material speed detection roll 10 is provided on the exit side of the third pass (final pass). The pull-out roll 7.8 and the detection rolls 9, 10 each have a rotation speed detector, for example, a pulse generator 11,
12, 13, and 14 are connected. Further, an inlet thickness gauge 15 is provided on the inlet side of the first pass, and an outlet thickness gauge 16 is provided on the outlet side of the third pass (final pass).

In FIG. 2, a predetermined increase 2 under pressure is applied between each work roll by a bender pressure control device (not shown). And in Figure 2, FID + F2D +
F3D IFIW IF2W I F3W each work is 0
It represents the set value of the increase bender pressure applied between the two cylinders, and the subscript "R" indicates the drive side side, and the subscript "W" indicates the work side side.

FIG. 3 is a block diagram showing an embodiment of the automatic plate thickness control device according to the present invention. In Fig. 3, the rib is a delay device, and this delay device uses the number N1 of pulses generated by the pulse generator 130 to delay the board thickness MIX detected by the inlet thickness gauge by a predetermined time to predict the inlet board thickness. It is output as a value HIM and given to the first pass mass flow plate thickness calculation device R (predicted value calculation device) 2].

This arithmetic device 2j uses the pulse generator 130 generated pulse number N1 and the drawer roll 70 position R (distance between the center of the drawer roll 7 between the first and second noses and the center of the second work roll 2) D2'Y. Pass exit side plate thickness prediction value h1M
is calculated and given to the delay device. Similarly, the delay device n is set to the second and fourth positions using the drawer roll 70 ftD2 and the number of pulses N2'l generated by the pulse generator 11.
The input side plate thickness prediction value H2MY is outputted and given to the second pass mass flow plate thickness calculation unit 23.

This plate thickness calculating device is a pulse generator 11. ,1
Based on the number of generated pulses N2 r N3 of 2, a second pass output side plate thickness predicted value h2M is calculated and given to the delay device array. The delay device row is the position of the pull-out roll 8 (distance between the center of the pull-out roll 8 and the center of the third work roll 3 between the 2nd and M3 passes)
D3 and the number N of pulses generated by the pulse generator 12
25 il: Halsge generator 12 which outputs the third pass inlet thickness predicted value H3M based on 3, and into which this predicted value H3M is input.
, 14 generated pulse number N3. A third pass exit side plate thickness prediction value h3MY is calculated based on N4. Also each 1st. Second. The predicted value h1Mjh2M r h3M of the third pass outlet side plate thickness is calculated from each of the first and second passes. Second. 3rd bass mass flow automatic gain control device (A
GC) 26, 27, 28. Each 1st.
Second. 3rd bass mass flow AGC (correction amount calculation device)
26, 27, and 28 are the first pass, the second pass, and the third pass, respectively.
The increase two-under pressure between the upper and lower work rolls of the pass is corrected and calculated, and the plate thickness at the exit side of each pass is independently controlled via an under-pressure control device (not shown). That is, in the first bus mass flow AGC 26, the first pass outlet side plate thickness prediction value h1M
Through the PI controller 29, which performs proportional/integral operation (PI operation), the deviation between the target value hlR of the first pass outlet plate thickness and the force l/second work roll increase Runder pressure set value correction amount ΔFl is determined. Calculate the 1st drive between the 2nd and 2nd work rolls.
By adding to the initial set value FID"TFIV? of increase bender pressure on the buzzer and work side, the 1st Φ
The incremental pressure setting values FED and FIW for the drive side and work side between the second work rolls are calculated and output to the R turn pressure control device.

2nd pass mass flow AGC with PI 118 gauge blade etc.
27 and the third pass mass flow AGC 28 having the PI controller 31, etc., has almost the same function as the fJfr l no W mass 70-AGC 26 described above. Furthermore, in FIG. 3, 32 is a plate thickness monitor device, and this monitor device 32 has a function for correcting the prediction error of the third pass outlet side plate thickness prediction value h3M. 32 is the deviation between the third outlet side plate thickness target value h3R and the plate thickness detected by the outlet side thickness meter h3X and is transmitted to the third bus mass flow AGC 28 as the plate thickness monitor function output Δh3R through the controller. ing.

Next, the operation of the automatic plate thickness control device will be explained in detail with reference to FIGS. 1 to 3.

The board thickness HIX detected by the entrance thickness gauge 15 is inputted for each delay device. Then, each delay device delays the detected board thickness HIX of the inlet thickness gauge by the time required for the material A to travel between the inlet thickness gauge 15 and the first pass, and outputs it as the first pass inlet board thickness predicted value HIM. do. When performing this delay calculation, it is necessary to know the running distance of the material on the first pass entry side. The distance traveled is calculated by counting the number of pulses generated by the pulse generator (N1). The predicted value HIM of the board thickness on the entrance side of the pass is inputted to the first bus mass flow board thickness calculation device 2.

Here, in the first pass, the material inflow volume and the material outflow volume are equal for a certain period of time, that is, within the sampling pitch 9, so the following equation holds true.

HIM@B11Lo=hIM number B+1L1...(1)
However, B; Plate width Lo of material A; Material travel distance between sampling pitches on the first bus entry side Ll; Material travel distance between sampling pitches on the first bus exit side This travel distance LQ, For Ll, input side pulse It is given by the following equation using the number N1 of generator generated pulses and the number N2 of pulses generated by the generator between the first and second pulses. Both Nl l N2 indicate the number of pulses generated between sampling pitches.

Lo = 2 K Ro X (N1/NIR)
---(2) Ll=2πRt X (N2/N2
R) ...(3) However, Ro: Inlet side material speed detection roll radius R1: First-second bus pull-out roll radius NIR; Pulse generator 13 per revolution of the inlet side material speed detection roll 9 The number of pulses generated N2Ry between the first and second pulses The number of pulses generated by the pulse generator 11 per rotation of the pull-out roll 7 In the first bus mass flow board thickness calculation device 2J, the
, (21, (31), the predicted value h1M of the first to second outlet side plate thicknesses is calculated according to the following equation (4), and is output to the delay device n.

The delay device n calculates the first pass outlet side plate thickness prediction value h1M by the time required for the material A to travel between the first pass and the second bus.
'al' is delayed and output as the second pass entry side plate thickness prediction value H2M. When performing this delay calculation, it is necessary to know the traveling distance between the first and second buses to the material as described above. , the number of pulses generated by the pulse generator 11 connected to the pull-out roll 7 between the first and second buses (between the 1st and 2nd buses)! The traveling distance is calculated by counting the number of pulses generated by the energizer (Nz'Y). However, since the material travel time between the first and second buses depends on the position D2 of the first and second pull-out rolls 7, the delay device n uses the position D2 of the first and second pull-out rolls 7.
2 to correct the delay time and improve control accuracy.

Thereafter, in the same manner, the final predicted third pass outlet thickness value h3M is calculated via the second bass mass flow thickness calculation device B, the delay device and the third mass flow thickness calculation device 25.

And each 1st. Second. 3rd bus exit plate thickness prediction value hIM
l h2M l h3M Each given first . In the second and third bus mass flow AGCs 26, 27, and 28, the first and second . By correcting the increase Runder pressure between the upper and lower work rolls of the third bus, the plate thickness at the exit side of each pass'
It is controlled independently. That is, the first pass mass flow A
In GC26, the deviation (hIR-h3M) between the first pass outlet side plate thickness target value hlR and the first pass outlet side plate thickness predicted value h1M
By passing it through the YPI controller 4, the increase inner pressure setting value correction amount ΔF1 between the 1st and 2nd work rolls is calculated. Furthermore, the following formula is calculated, and the drive side increase inder pressure setting value F between the first and second work rolls is calculated.
ID and the work side increase R under pressure set value FIW between the first and second work rolls are output to an ingu pressure control device (not shown) to control the first pass outlet side plate thickness to a target value.

FiD=Fxn”tΔF1”(5
)F'tw=F"1V?+ΔFl-(6) However, FI
D"; Initial setting value of drive side increase R under pressure between 1st and 2nd work rolls F1v?s Initial setting value of work length increase R under pressure between 1st and 2nd work rolls, 2nd pass mass flow AGC27 , the same process is performed for the third mass flow AGC 28, and the drive side increase bender pressure set value F2D between the second and third work rolls, and the work side increase R under between the second and third work rolls, respectively. pressure setting value F2W and the third
・Outputs the drive side increase under pressure setting value F3D% between the 4th work roll and the work side increase R under pressure setting rmFsw between the 3rd and 4th work rolls,
The outlet plate thicknesses of the second pass and the third pass are independently controlled to target values through a four-under pressure control device.

In addition, M [1+2nd, i3 pass mass 7o-AGC2
Each Pl controller in 6, 27, 28 29, 30
.

31, the relationship between the j-th pass exit side plate thickness target value hjB and the 3rd/z pass exit side plate thickness prediction value h3R is hJR> hjM However, when j=1, 2.3, ) Change the work roll increase R under pressure setting value correction amount ΔFj'i in the increasing direction, and when Ji<JM, ΔFj'a? Change in the direction of decrease. this is,
When the increase R under pressure between the upper and lower work rolls of the jth pass increases, the thickness of the first pass outlet side increases, and the increase R
It utilizes the principle that as the under pressure decreases, the thickness of the first pass outlet side decreases.

Further, an output signal from a plate thickness monitor device 32 is given to the third pass mass flow AGC 28 . That is, the monitor device 32 compares the detected plate thickness h3x of the outlet side thickness actually detected by the outlet thickness gauge 16' with the predicted value h3R of the 3rd/ZE outlet side plate thickness, and calculates the deviation (h3R-hsx )YP
I Thickness monitor function output Δh3 of the thing passed through the controller
It is given to the third bus mass flow AGC 28 as R. As a result, the pre-processing difference of the third pass exit-side plate thickness predicted value h3H is corrected.

In the above embodiment, in one-stand multi-pass rolling, the plate thickness detected at the inlet side of the first nozzle is used to successively predict the plate thickness at each bus outlet side, and the plate thickness at each bus outlet side is predicted. Based on the value, increase the Runder pressure between the upper and lower work rolls of each bus FID + FIVF + F2D + F' seat tF3
Since D I FaW is corrected, the thickness of each bus outlet side plate can be independently controlled to a degree of tN. Furthermore, if the plate thickness delay calculation between each A space is corrected based on the pull-out roll position D21 D3, and the predicted value of the final pass outlet side plate thickness is corrected using the detected plate thickness of the outlet side, the plate thickness can be corrected. Thickness accuracy and responsiveness can be greatly improved.

[@The effect of light! F! ,, ] As explained above, in the present invention, in l-stand multi-pass rolling, the plate thickness 2 detected at the entrance side of the first rolling bus is used to successively predict the plate thickness at the exit side of the valley rolling pass, and Since the increase inder pressure between the upper and lower work rolls of the valley rolling and V-stripes is corrected based on the predicted value of the exit side plate thickness, the exit side plate thickness of each rolling pass can be controlled independently, which improves the plate thickness accuracy and responsiveness. can be improved.

[Brief explanation of drawings]

FIG. 1 is a side view of an l-stand multi-bus rolling mill to be controlled by the present invention, FIG. 2 is a front view of FIG. 1, and FIG. 3 is a configuration of a plate thickness control device according to an embodiment of the present invention. It is a diagram. 1.2, 3.4...Work roll, 5.6...Back row #, 7.8...Drawer roll, 9.10...To detection row 11, 12, 13, 14...・Pulse generator, 15, 16...Thickness gauge, 20, 22.2
4...delay device, 2], 23, 25...max
FR: r-Plate thickness calculation x device, 26, 27. 28... Mass flow AGC, 29, 30, 31... PI controller,
32... Plate thickness monitor device,... PI controller, A.
...Rolled material. Applicant's agent Kiyoshi Inomata Figure 1 6 Figure 2

Claims (1)

[Scope of Claims] 1. A method of stacking 13 or more work rolls to form at least two or more rolling passes, and rolling the material by continuously passing it through these rolling passes. In the stand tanos rolling mill, a thickness gauge detects the thickness of the material to be rolled before rolling, and a plurality of speed detectors detect the running speed of the material to be rolled on the entry side and exit side of each rolling pass. The traveling time of the material to be rolled on the entrance side of the first rolling pass is calculated based on the detection signal of the speed detector installed on the entrance side of the first rolling pass, and the detection signal of the thickness gauge is calculated for this traveling time. a delay device that delays and outputs the predicted value of the plate thickness at the entrance side of the first rolling pass; and a delay device that outputs the predicted value of the plate thickness at the entrance side of the first rolling pass; A predicted value calculation device that calculates a side plate thickness prediction value, and a deviation value between the output value of this predicted value calculation device and the exit side plate thickness target value of the first rolling pass is calculated and the upper and lower work rolls of the first rolling and dark strip are calculated. A correction amount calculation device is provided to calculate the correction amount of the increase inder pressure setting value between the two rolling passes, and the correction amount is calculated on the entry side of the other rolling pass based on the detection signal of the speed detector provided on the entry side of the other rolling pass. a delay device that calculates the running time of the material to be rolled, delays the output signal of the predicted value calculation device by the running time, and outputs it as a predicted value of plate thickness at the entrance side of another rolling pass; and an output value of this delay device and the above-mentioned others. a predicted value calculation device that calculates a predicted value of plate thickness at the exit side of another rolling pass based on the speed detection signals of the entrance and exit sides of the rolling pass; A correction amount calculation device that calculates the deviation value from the target side plate thickness value and calculates the correction amount of the increase inder pressure setting value between the upper and lower work rolls of other rolling passes is provided for the number of cylinders of the other rolling passes. A plate thickness control device for an L-stand multi-pass rolling mill, characterized in that: 2. The control device according to claim 1, wherein the correction amount calculation device calculates the predicted value of the rolling A-strip outlet side plate thickness and the rolling no.
The l-stand multi-pass rolling mill is designed to calculate the amount of correction of the increase R under pressure setting value between the upper and lower work rolls by calculating the amount of deviation from the target value of the plate thickness on the exit side and performing proportional integration on the amount of deviation. Plate thickness control device.