JPS6186019A - Plate thickness controlling method in steel plate rolling - Google Patents

Abstract

PURPOSE:To reduce a plate thickness deviation by performing a rolling reduction control so as to make the tip, etc. of a strip in the target plate thickness shown by a specified gage meter method respectively until and after reaching the plate thickness gage at the stand outlet side. CONSTITUTION:A rolling reduction position detector 4 is provided on a rolling reduction device 2 and a rolling reaction force detector 3 is arranged on a rolling mill 1. An arithmetic control device 7 finds a rolling reduction position so that the plate thickness at the output side estimated by a gage meter equation (1) is made the target plate thickness when the detector 3 shows a plate biting and sets it to a rolling reduction position control device 8. When the tip of a strip 9 reaches a plate thickness gage 5 then, the surveyed plate thickness value hm of the plate thickness gage 5 is read, the deviation with the target plate thickness (h) is introduced to a gage meter equation (II) and the rolling reduction position is set up so as to make the estimated plate thickness the target plate thickness. In succession, further a monitor feedback AGC is performed. In this method the plate thickness deviation is reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to plate thickness control in steel plate rolling, and in particular, when the strip tip (or the plate thickness change point in the case of continuous rolling) reaches the rolling stand. Monitor feedback from A
The present invention relates to plate thickness control up to the start of GC (own plate thickness control) and the start timing of the AGC.

[Conventional technology]

Monitor feedback is required because the relationship between the target value and the actual thickness as the rolling result is unknown until the end of the strip is bit into the rolling mill and the actual thickness of the strip is obtained using the thickness gauge at the outlet of the stand. AGC cannot be performed. Conventionally, until the measured plate thickness is obtained, the rolling position is controlled so that the plate thickness estimated by the gauge meter type % formula becomes the target plate thickness. (after reaching the thickness gauge), the monitor feedback AG
Start C.

[Problem that the invention seeks to solve]

However, until the monitor feedback AGC is started, the reduction position control using the gauge meter type is a feedback control with extremely short dead time, so if the deviation between the actual plate thickness and the target value is large, the monitor feedback AGC will be started. When the monitor feedback A
When the GC gain is small, it takes a long time for the actual plate thickness to converge to the target plate thickness, and when the gain is large, hunting occurs and it takes a long time for the actual plate thickness to converge to the target plate thickness. The thickness of the plate that deviates from the deviation becomes longer, or the thickness of the plate with a large deviation increases.

The primary purpose of the present invention is to reduce the plate thickness deviation at the start of monitor feedback AGC, and also to shorten the time until the AGC stabilizes, and to reduce the plate thickness deviation until the monitor feedback AGC is started. This is the second purpose.

[Means for solving problems]

In order to achieve the above object, in the present invention, (A)
From the time the strip tip (or, in the case of continuous rolling, the thickness change point 2 and below) reaches the stand until it reaches the thickness gauge at the exit side of the stand, the thickness estimated by the gauge meter type % formula % is the target plate thickness. (B) After the tip of the strip reaches the thickness gauge on the outlet side of the stand, the difference between the thickness ho+ detected by the thickness gauge and the target thickness during rolling at the detection point is determined. The rolling position is controlled so that the plate thickness estimated by the gauge meter type % formula % corrected by ε = hm - h becomes the target plate thickness; (C) The rolling point when the strip tip reaches the plate thickness gauge is After reaching the plate thickness gauge, monitor feedback AGC is performed using the plate thickness detected by the plate thickness gauge.

Referring to FIG. 1, to explain the case where a divided strip is rolled in a rolling mill I, after the strip 9 is bitten into the rolling @l, the tip Top of the strip 9 is detected by the plate thickness meter 5 on the exit side. Up to [(A) in FIG. 1], the rolling position is controlled so that the plate thickness estimated from the gauge meter formula h=P/M+So+Sh becomes the target plate thickness. In addition, So is the pressure lower part of the roll 1. sh is heat crown.

When the tip Top of the strip 9 reaches the plate thickness gauge 5 and the actual plate thickness value can be obtained [(B) in Fig. 1], the actual plate thickness value hm and the target plate at the point where the measured value was obtained are obtained. Deviation from thickness ε
= Gauge meter formula h = P/M + S, corrected by hm - h
The rolling position is controlled so that the plate thickness estimated by +Sh+ε becomes the target plate thickness. 29, the plate thickness deviation becomes smaller.

Next, when the tip TOρ of the strip 9 is detected by the plate thickness gauge 5,
(C) in the figure], monitor feedback AG is started, and monitor feedback AGC is continued thereafter [first
(D') in the figure.

[Effect]

According to this, the reduction position control using the gauge meter method in (A) above until the start of monitor feedback AGC is feedback control with extremely short dead time, but there is a possibility that the gauge meter method contains errors. Therefore, the deviation between the actual plate thickness and the target value may be large.

However, due to (B) above, the deviation is reduced by a correction that reduces the deviation, and when the deviation is small at the start point of the monitor feedback AGC in CG) above and the monitor feedback AGC is started, the deviation is reduced. Regardless of the magnitude of the gain, the actual plate thickness converges to the target plate thickness smoothly and quickly.

As a result, the plate thickness deviation at the start of the monitor feedback AGC is small, and the time required for the AGC to stabilize is short. Furthermore, the plate thickness deviation before starting monitor feedback AGC is small.

〔Example〕

FIG. 2 shows an outline of the construction of an apparatus for carrying out one embodiment of the present invention. In this, 2 is a rolling down device, 3 is a rolling reaction force detector, 4 is a rolling position detector, 6 is a roll peripheral speed detector, 7 is an arithmetic control device including a monitor feedback AGC device,
8 is a lowering position control device. The roll circumferential speed detector 6 generates a speed detection pulse (plate speed signal) at a rate of 1 pulse per rotation of the work roll through a predetermined angle. The rolling reaction force detector 3 outputs the rolling reaction force signal, the rolling position detector 4 outputs the rolling position signal, the plate thickness meter 5 outputs the plate tip arrival signal and the measured plate thickness signal, and the roll peripheral speed detector 6 outputs the plate tip signal. A speed signal is given to the arithmetic and control unit 7.

The arithmetic control device 7 performs the above-mentioned plate thickness control based on these signals and target plate thickness data given from the host computer.

An outline of the plate thickness control by the arithmetic and control unit 7 is shown in FIG. To explain this, when the rolling reaction force signal from the rolling reaction force detector 3 indicates plate jamming (step l), the arithmetic and control unit 7 determines that the outlet side plate thickness estimated by the gauge meter type % formula % is Find the rolling position so that the target plate thickness is achieved, and set this in the rolling position control device 8 (
Step 2). Next, the tip of the strip 9 is rolled 81
Initialize (clear) the first counter and second counter for racking the movement position and movement amount from (step-3), and The second counter starts counting up (step 4).

Thereafter, refer to the count value of the first counter and the count value of the second counter (step 5.6).

The count value of the second counter is the predetermined movement amount ΔL (rolling mill 1
- When the value corresponds to the distance L1 between the plate thickness gauges 5), the rolling position setting (1) is performed in the same way as step 2 (step 7), and the second counter is initialized and starts counting again ( 8).

The lowering position setting (1) similar to step 2 is performed every time the strip 9 advances by a predetermined movement amount ΔL until the count value of the first counter reaches a value corresponding to Li.

When the count value of the first counter reaches a value corresponding to rolling mill l - plate thickness meter 5 distance a L 1 (when the tip Top of strip 9 reaches plate thickness meter 5), the plate of plate thickness meter 5 Read the actual thickness value h + m (step 9), introduce the deviation t = hm - h from the target plate thickness at this point into the gauge meter formula, and use the modified gauge meter formula h = P / M + S o +
The rolling position is set so that the plate thickness estimated by S h + ε becomes the target plate thickness (step 10). Then clear the first counter and the second counter (Step 11)
, the first counter and the second counter start counting (step 12).

Next, referring to the count values of the first counter and the second counter (step 13.14), when the count value of the second counter reaches a value corresponding to the predetermined movement amount ΔL, the actual plate thickness value hm is read ( Step 15), perform the lowering position setting (2) in the same way as step 10 (step 16), and
Initialize the counter and start counting again (17
). Every time the strip 9 moves a predetermined amount ΔL until the count value of the first counter reaches a value equivalent to Li, step 1
Perform the lowering position setting (2) similar to 0.

When the count value of the first counter reaches a value corresponding to 1, which is the distance between the rolling mill l and the plate thickness gauge 5 [when the rolling position A of the strip 9 (see Fig. 1) reaches the plate thickness gauge 5], Monitor feedback A using the actual plate thickness value ha of plate thickness gauge 5
Start GC18), and then monitor feedback A until detecting a plate failure based on the signal from detector 3.
Continue GC. When the board comes out (step 19), the board waits for the board to engage (step 1).

Note that in this embodiment, monitor feedback AGC
performs rolling feedback AGC to control the rolling force P according to the deviation Δh between the measured plate thickness and the target plate thickness at the measurement point.

During continuous rolling, the plate engagement in step 1 and the plate omission in step 19 of the control flow described above are interpreted as the arrival of the plate thickness change point.

〔Effect of the invention〕

As described above, according to the present invention, the plate thickness deviation at the start of monitor feedback AGC is small, and the time required for the AGC to stabilize is short. Furthermore, the plate thickness deviation before starting monitor feedback AGC is small.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the control switching timing of plate thickness control of the present invention, FIG. 2 is a block diagram showing an overview of the configuration of a device that implements the present invention in one embodiment, and FIG. 3 is a control operation of the arithmetic and control unit 7. It is a flowchart showing an outline.

Claims (1)

[Claims] From the time the strip tip or the point of change in thickness reaches the stand until it reaches the thickness gauge at the outlet side of the stand, the thickness estimated by the gauge meter formula h=P/M+S_0+Sh is set as the target thickness. After the tip of the strip or the thickness change point reaches the thickness gauge on the outlet side of the stand, the difference ε between the thickness hm detected by the thickness gauge and the target thickness during rolling at the detection point is ε= The rolling position is controlled so that the plate thickness estimated by the gauge meter formula h=P/M+S_0+Sh+ε corrected by hm-h becomes the target plate thickness; Rolling when the strip tip or the thickness change point reaches the plate thickness gauge After the point reaches the plate thickness gauge, monitor feedback AGC is performed using the plate thickness detected by the plate thickness gauge; plate thickness control method in steel plate rolling.