JPS59147710A - Method and device for controlling sheet thickness - Google Patents

Abstract

PURPOSE:To improve the sheet thickness accuracy of a rolling material by correcting the transferring time of the material basing on the difference between the time required for transferring a sheet thickness varying part from a thickness gauge to an objective stand of operation and the time required for changing the rotational speed of a preceding stand by a feed forward AGC. CONSTITUTION:A welding point detector 21 for detecting the welded point of a rolling material 2 is provided to the rear stage of a deflector roll 4 to output its signal to a feed forward (FF)AGC10, and the thickness of the material 2 after passing through the stand No.1 is measured by a thickness gauge 3 to output the thickness deviation to the FFAGC10. Further, a rolling pressure of the stand No.2 is detected by a load cell 22 to output it to a transferring-time calculating circuit 23. The difference DELTAS between the times S1, till the welded point of the material 2 reaches the No.2 stand after passing through the gauge 3, and the time S3, till the rotational speed of a work roll of the stand No.1 is changed by an utput of the FFAGC10 after the welded point asses through the gauge 3, is calculated, and the transferring time of material 2 is corrected by the difference DELTAS.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plate thickness control method and apparatus most suitable for feedforward control of a cold tandem mill or a lino-mill warehouse.

In recent years, feedforward (FF) AGC is often adopted in Tahari and Kusu mills in the front stage of cold tandem mills to improve ratio and capacity.
The basic configuration is to detect the plate thickness with a thickness gauge, and at the moment when the outside of the plate thickness correction section reaches the target of operation, directly under the next stand, the 18i1 arithmetic circuit and control unit control the plate thickness or speed during transfer. It is something that changes.

Methods for performing FFAGCi can be roughly divided into methods using reduction and methods using speed. Figure 1 shows FFAG due to pressure reduction.
This shows an example of C, where multiple stands 1 (Nol, No.
2. ...N+)ni and each stand H'7-consists of crawl 11 and backup roll 12)? In a machine that cold-rolls the rolled material 2 by sending it into a cold tandem mill, a thickness gauge 3 that reaches the thickness of the steel strip 2 is provided at a distance of Ll on the entry side of the Nol stand, and a thickness gauge 3 that reaches the thickness of the steel strip 2 is further installed.
A deflector roll 4 is provided at the front stage. A pulse transmitter 5 for detecting the transfer speed of the rolled material 2 is connected to the deflector roll 4 . Pulse transmitter 5 and thickness i
Each output signal of t3 is fed to a feedforward AGC device (
Based on these signals, the FFAGC device 6 controls the pressure T device 7 that adjusts the amount of reduction to the backup roll 12.

Figure 2 shows an example of FFAGC based on speed, and shows the distance between the No. 1 stand and the No. 2 stand (one distance before the No. ), and a Norculus transmitter 5 is connected to the work roll 11, and based on the output signals from these, the FF'AGC device 8 drives the mill motor 9 to drive the work roll 11. Control.

In the above configuration, in the configuration shown in Figure 1, the point directly below the Nol stand is the operating point to control the rolling ME', and in the configuration shown in Figure 2, the No. 2 stand is the operating point and the rolling roll of the Nol stand is controlled. Controls the rotation circuit. In either case, the transfer time is determined by inputting the speed of the sail material 2, the response delay of the thickness gauge, the response delay signal of the manipulated variable, etc.
There is a need to perform calculations on a C device.

However, it is actually difficult to actually measure the speed of the rolled material, and the speed of the rolled material is usually determined indirectly by detecting the rotational speed of a deflector roll or a work roll of a Nol stand. For this reason, when using deflector rolls, it is affected by roll slip, and when using work rolls, it is affected by fluctuations in the advance rate of the plate, so it is difficult to accurately calculate the total transfer time for all rolled materials. It's hard to do.

Therefore, in the past, it was not possible to sufficiently improve the AGC effect when controlling the plate nozzle.

The purpose of the present invention is to accurately estimate the transfer time of the rolled material and to
9- A method and apparatus for controlling plate thickness that improve corrosion are provided.

Unexploded EJJ is determined by the time S2 from the time when the rapid plate thickness variation part that passed through the thickness plate provided upstream of the stand to be operated passes through the thickness h until it reaches the stand to be operated, and the thickness. ! According to the output of FFAGC while passing through 1,! 1) The difference ΔS from the time S3 until the work roll rotational speed or rolling position of the NOI stand changes is calculated, and the transfer time Tof of the rolled material is corrected by this ΔS.

FIG. 3 is a block diagram showing one embodiment of the present invention, illustrating the case where it is applied to the FFAGC system with the speed shown in FIG. (Therefore, parts that are the same as those shown in FIG. 2 are given the same reference numerals.

Duplicate explanations will be omitted. ) In this embodiment, a part (welding point) where the plate thickness of the rolled material 2 suddenly changes is detected at the downstream stage of the deflector roll 4, and the FFAGC
A welding point detector 21 that sends out a signal to the No. 2 stand, a load cell 22 that detects the rolling pressure of the No. 2 stand, and a transfer correction circuit 23 that corrects the transfer time based on each output signal of the welding point detector 21 and load cell 22. This is an addition to the configuration shown in FIG.

In the above configuration, the thickness deviation of the rolled material 2 that has passed through the -Nol stand is detected by the thickness deviation 3, and the detected value is output to the FFAGC 10.

In realizing the present invention, it is important to change the speed of the Nol stand at the same time when the R deviation detection part moves by a distance L2 from the installation position of the thickness gauge 3 and reaches directly below the -NO2 stand. This operation is performed by the transfer time calculation circuit 23.

Distance from thickness gauge 3 to just below No. 2 stand 'e
L (tm) and the Nol stand of rolled material 2 ~
Movement speed between No. 2 stands k V (mys/se
c), then the above transfer time T(see) is.

L T=-・・・・・・・・・・・・・・・(1)■ In the control of 8 degrees, which can be controlled by ■, the thickness gauge, AGC control circuit, and motor? Each of the Ii control circuits has dead time, but if each dead time is '&T+-Tz-Ta,
The transfer time To is expressed by the following formula.

In equation (2), it is difficult to directly detect the transfer speed V online. Therefore, the rotation speed of the work roll of the -Nol stand is detected by the pulse transmitter 5 and used as a substitute. If the work roll rotation speed tr (rotations/5ecL) and the work roll diameter are /(im)-advanced rate of the rolled material in the Nol stand ef+, then the transfer speed V is expressed by the following equation.

■=πrl(1+f+) ・・・・・・・・・・・・
... (3) In general, the advance rate f changes by several degrees depending on the rolled material and rolling conditions, and it is said that it is very difficult to accurately calculate and examine this value. Since it is not possible to determine the value from a set table value, the value often deviates due to changes in the rolled material and rolling conditions.

Therefore, in the present invention, the optimum transfer time is always determined regardless of the change in the advance rate, and thereby the original effect of FFAGC is brought out.

Rolled materials have welds in order to carry out continuous rolling, where the thickness of the material changes rapidly. Furthermore-N.

When passing through the second stand, the rolling pressure signal also changes in a spiral pattern. Therefore, in the present invention, these two changes are detected and utilized for control. A sudden change in plate thickness is detected by a welding point detector 21, which is a sudden change in plate thickness detector, and a transfer time correction circuit 23 is activated based on this detection signal.

Plate thickness deviation signal when the welded part passes through all three thickness gauges, or
The time when it is detected that the amount of change in the differential value has exceeded the preset value is defined as Sl, and the rolling pressure value when the first bath contact part passes through the No. 2 stand or the amount of change in the differential value has exceeded the set value. The time point 'ts2' is defined as the point in time when the difference is detected, and the time point tss is defined as the time point in which the peak of the differential value of the work roll rotational speed in the Nol stand, which has changed due to the -FFAGC output, is detected. If all dead time on the rolling pressure side is ignored, the calculation of the transfer time has been performed correctly when -52=33. Deviation ΔS1ΔS between S2 and 83
= 82-83 (sec)' ・---------
--(4), and by constantly correcting (2) the transfer time T by this deviation. can always be performed correctly for all rolling materials and rolling conditions. It is desirable to obtain To each time the welding point passes through the thickness gauge 3. For example, + To is a rolled material.

The effect of FFAGC can be further improved by calculating the MTo' for each 118 conditions and using it from the first grain after changing the material to the actual MTo' at the time of the previous rolling.

Figure 4 is a flowchart showing the above-mentioned processing in the inter-portion correction circuit 23.

Dota. FIG. 5 is an explanatory diagram of conventional control.

FIG. 6 is an explanatory diagram of control in the present invention. That is.

Figure 5 shows the case where the transfer time is not adjusted.
FIG. 6 shows a case where the transfer time is adjusted correctly.

FIG. 5(a) shows the time when the welded portion is detected by the thickness section 3, and FIG. 5(1)) clearly shows when the welded portion has arrived at the stand 102. The overwhelming treatment at this point? Fig. 5 (c) shows the result of copying, but due to the speed change at the -Nol stand, the transfer time is delayed by ΔS, and there is a discrepancy between the transfer state and the reduction flt: control +:i''+7 Fig. (
There's a huge difference between the J and the final stand, just like in Al.

On the other hand, according to the present invention, FIG. 6 1(t) 1. (c
) As shown in No. 2 stand pressure 41L pressure differential I
n, (% where the welding part is directly under the No. 2 stand: ;if+
82 and the speed culture timing S3 of the Noh stand completely match, indicating that correct control is being performed. In this case, the h.3 final stand plate is as shown in Figure 7 (b), and it is painful to see irregularities in the plate thickness.

An example of FFAGC based on speed has been shown above, but an example of FFAGC based on reduction will be described next.

FIG. 8 shows another example of the present invention, and since the same reference numerals are used for the same parts as shown in FIGS. 1 and 3, the explanation will be omitted. .

R min 13 children - Move to the first stand (L+ distance) 1. = Move the rj-docel 22 to the first stand, remove the bath contact detection device 21, and set the deflation crawl to 40 revolutions? The configuration includes three pulse generators 24 that detect and send out pulses to the FFAGC device (j).

In the above configuration, when the sudden change in thickness of the rolled material (for example, the welding point) passes through the installation +f position of the thickness gauge 3,
Detection No. 16 detects the plate no. V, exceeding the set value by 7 degrees, and from this point of detection, the load cell 22 indicates that the sudden change in plate thickness has reached the stand to be operated (No. 2 stand).
What is the time s2 until the output signal level of the rolling pressure Kmr is detected and the number of revolutions of the deflector roll 4? Deviation ΔS from the transfer time s3 detected by the pulse generator 24 and calculated by calculation.

By constantly correcting equation (2) with ΔS252-s3, the transfer time is corrected.

In the above embodiment, an example is shown in which differential values are used for both the rolling pressure signal and the Nol stand speed change signal, but if the change group is large, a single signal tone may be used as is.

In addition, in the case of this example, the waste time rI+1 due to the rolling pressure can be ignored and the degree of rotation can be reduced to 6, but furthermore.

It is also possible to electrically correct this dead time.

As is clear from the above, according to the present invention, it is possible to improve the accuracy of the 7th plate thickness by accurately correcting the transfer time.

4. Simple explanation of F&I in FIG. 1 FIG. 1 is a diagram showing the configuration of an F A G C using a conventional rolling force, and FIG. 2 is a diagram showing a configuration of an F A G C using a conventional speed.

Fig. 3 is a block diagram showing an example of the present invention; Fig. 4 is a processing flowchart in the transfer time correction circuit according to the present invention; Fig. 5 is an explanatory diagram of control in a conventional configuration; Fig. 6:
71 is an explanatory diagram of the limitation 1 of the present invention, No. 71 is a deviation diagram of hanging material stand plates of the conventional and the present invention, and FIG. 8 is a configuration diagram showing another embodiment of the present invention.

4... Deflector row A1.5.24... Pulse transmission 6- Ri... Mill motor 10... Feed forward AGC-11... l/-7/Roll-12...
・Hack a la crawl, 2]...Welding point detector, 22
...Load cell L, 23, 23'... Gradual feed positive circuit.

Agent Tatsuyuki Unuma (2 others) Figure 5 Sl Figure 6 1 No. 7 [”a (b)---

Claims (2)

[Claims] (1) Feedforward A based on speed or reduction
Materials to be processed by rolling stand controlled by GC?
In rolling equipment that rolls sheets to the desired thickness. When the detected value of the thickness gauge that measures the plate thickness change on the upstream side of the operation target stand exceeds the set value, the timing at which this plate thickness variation point arrives at the operation target stand and the feedforward AGCV? ljD Correcting the transfer time of the rolled material based on the time difference between the timing when the pressure Fi of the stand to be operated is controlled to 1u or the timing when the same rotational speed of the rolling rolls in the rolling stand preceding the stand to be operated is controlled. A method for controlling plate thickness. (2) In a rolling equipment that rolls the material to be rolled to a desired thickness by a rolling stand controlled by a feedforward AGC with a speed or reduction based on a detected value of the thickness of the material to be rolled and a transfer speed, The pressure reduction amount detector of the stand to be operated with the pressure reduction amount detector. Thickness 81, which measures the plate thickness on the downstream side of the AGC control stand, and the thickness 81 measured at the stand to be operated from the thickness hole.
A transfer time for correcting the rolling material transfer time between the thickness gauge and the controlled stand based on the deviation between the first transfer time during which the rolled material is transferred and the second transfer time calculated by the feedforward AGC. A plate thickness control device comprising: a correction circuit.