JPS61180607A - Control method for sheet thickness in rolling made for changing sheet-thickness during rolling - Google Patents

Abstract

PURPOSE:To prevent the off-gauge of an outlet-side sheet-thickness at a sheet thickness changing point and to reduce the length of a sheet-thickness varying part, by stopping AGC used for controlling a draft position by a gauge meter system, and starting the AGC when a changing point comes in rolling made for changing a sheet-thickness during rolling. CONSTITUTION:AGC for controlling a draft position so that an outlet-side sheet thickness estimated by a gauge meter system at the time t0 of starting the changing of a draft position coincides with a target sheet-thickness is stopped, and is started at the time t1 (a draft position is approximate to an intermediate value between S1 and S2) when a sheet-thickness changing point comes. At that time, as the draft position is approximate to the intermediate value, a draft-position changing, which successively changes the draft position toward S2 even by the AGC, is continued as well as the draft position adjustment corresponding to the deviation of an inlet-side sheet thickness is added to the draft position changing at the same time, and as the AGC is stabilized when the draft position is stabilized at S2 or in its vicinity, an off-gauge is not produced in the outlet-side sheet thickness at an sheet-thickness changing point and the length of a sheet-thickness varying part is reduced.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to plate thickness control in the rolling of continuously rolled materials having different thicknesses, and in particular to AG control before and after the thickness inflection point i of the rolled material.
Regarding C (automatic plate thickness control).

[Conventional technology]

Various methods of rolling with varying plate thickness during running are known, such as Japanese Patent Application No. 19211/1972 and Japanese Patent Application No. 15646/1982.

For example, as shown in FIG. 4, the entrance side plate thickness is 4. .

ll11 to 3. 'AGC at the change in plate thickness to 7mm
If you continue as is, that is, AG at the entrance side plate thickness change point.
If C is performed, the thickness of the exit side plate changes greatly at the change point, resulting in off-gauge.

Therefore, in the past, as shown in FIG. 5, the rolling position was changed just before the entry side plate thickness change point arrived.

Start changing from the rolling position s1 corresponding to the front entry side plate thickness H1t to the rolling position ws2 corresponding to the succeeding entry side plate thickness H2, stop AGC at this start time, set the rolling position to 82, and then start AGC ( For example, patent application No. 57-20957
No. 0).

In this case, in order to match the time center point of the speed change accompanying the plate thickness change with the time point center point of the rolling position change (change from Sz to 82), the time point before the plate thickness change point arrives. Start changing the rolling position.

This is because the rolling position change speed is slower than the rolling speed change speed.

[Problem that the invention seeks to solve]

In such rolling while changing plate thickness, the AGC is stopped while the rolling position is changed (from 31 to S1), so during that time, the initial setting error of the rolling position of the next rolled material (H2) and the off-gauge of the entrance side plate thickness are etc., resulting in an unsteady part of the outlet plate thickness, such as off-gauge.

An object of the present invention is to shorten the unsteady portion when changing the rolling position.

c Means for Solving Problem] In order to achieve the above object, in the present invention, before the plate thickness changing point arrives, the rolling position is changed to a rolling position corresponding to the thickness of the rolled material after the plate thickness changing point. When the plate thickness change point arrives, the rolling position corresponding to the plate thickness of the rolled material before the change point and the rolling position corresponding to the plate thickness of the rolled material after the change point, or the rolling position before and after the change point. In running strip thickness change rolling, in which the rolling position is changed in accordance with the thickness change point at a timing and speed of The AGC that controls the lowering position is stopped so that the position is changed, and the AGC is started when a change point arrives.

That is, as shown in FIG. 1, when starting to change the rolling position, 1.
), the AGC is stopped, and the AGC is started at 1+ when the plate thickness change point arrives (the rolling position is approximately at the midpoint between Sl and Sl).

[Effect]

According to this, when AGC is started (tl) to control the rolling position so that the outlet side plate thickness estimated by the gauge meter type % formula becomes the target plate thickness, the rolling position is approximately at the intermediate value. The AGC continues to change the rolling position to 82, and at the same time, the rolling position adjustment corresponding to the deviation in the entrance side plate thickness is added to the rolling position change, so that the rolling position is changed to 82 as before.
When the value stabilized by the AGC action is reached at or around that value, the AGC is stable, and approximately, the time until stabilization as in the conventional method m t. -t for t3 (Fig. 5)
o to ta (Fig. 1), which significantly shortens the off-gauge length.

For example, when the entry side plate thickness H1 before the change point is 4.0 mm and the entry side plate thickness H2 after the change point is 3.7 mm, by controlling 800 on and off as described above, the exit side plate thickness will be as shown in Fig. 2. However, there is no off-gauge in the exit side plate thickness at the plate thickness change point, and the length of the plate thickness variation part is short.

〔Example〕

FIG. 3a schematically shows the configuration of an apparatus for carrying out one embodiment of the present invention.

Figure 3a shows the rolling control system and speed control system of a 5-stand tandem rolling mill, where 1 indicates a rolled material.

2 is a rolling mill, 3 is a rolling device, and 4 is a rolling control device.

5 is an electric motor, 6 is a speed control device, 7 is a size change point detection device, 8 is a pulse oscillator synchronized with the roll rotation speed, 9
10 is a tracking device that tracks the plate thickness change point using a detection device 7 and a pulse oscillator 8 and outputs an output timing signal of the reduction and speed each time the stand passes; 10 is a reduction change device that changes the reduction position based on the reduction output timing signal;
11 is a speed changing device that changes the speed based on a speed output timing signal, and 12 is a running schedule changing device that calculates a formula for changing the rolling reduction and speed when the plate thickness changing point passes each stand.

An example of the change timing of the reduction and speed when changing the running schedule is shown in FIG. 3b. In FIG. 3b, vl, v2.
・・v5 is the speed before plate thickness change, Vt', V2', ・・
vs' is the speed after changing the plate thickness, 51tS2t...
S5 is the rolling position before plate thickness change, S1'*S2'* ・
・Ss+ indicates the rolling position after changing the plate thickness.

Here, taking as an example the point at which the plate thickness change point passes through the second stand, when the change point passes through the second stand, the speed of the first stand is changed to the next schedule, so that Between the 1st stand and the 2nd stand,
The speed ratio of the next coil is changed. The tension between the first stand and the second stand fluctuates as the first stand speed changes, but the lowering position of the second stand is changed to absorb this one tension fluctuation. Generally, the rate of change in speed is faster than the rate of change in the rolling position, and if you change the speed and rolling position of the first stand at the same time as in the past, the difference between the speed and the changing time of rolling will cause the first stand to change faster than the rolling position. The tension between the stand and the second stand will vary.

Therefore, the speed change formula for each stand (ΔVi=Vi−Vi
') Find the speed and reduction change time from the reduction change allowance (ASi=Si-5i'), and make sure that half of the speed change of the first stand is completed when the plate thickness change point passes the second stand, and Change the speed and pressure when the stand pressure change is half completed, and
This suppresses tension fluctuations between stands.

Thereafter, the timing of changing the speed and reduction is controlled so that the temporal center point of the speed change and the temporal center point of the reduction change coincide even when the plate thickness change point passes through the rear stage stand.

In this example, the invention is implemented in the first stand.

In the figure, 21 is a rolling reaction force detector, 22 is a rolling position detector, and 23 is an arithmetic and control device that executes AGC.

The arithmetic and control device 23 includes a pressure change device 10 at a time point 1 (1).
The target pressure reduction position is given by the tracking device.
A reduction change instruction signal is given at time Q, a change point signal is given from the tracking device at time 11, and target thickness data is given from the running schedule change device 12 when setting and changing the exit side thickness.

The arithmetic and control device 23 performs AGC and its on/off control as shown in FIG. 3c based on these signals and data, the rolling reaction force P detected by the detector 21, and the rolling position detected by the detector 22. That is, when the schedule change point does not arrive.

AGC is executed to instruct the reduction control device 4 to adjust the reduction position in a direction in which the calculated value obtained by substituting the detected value P into the gauge meter type % expression % becomes the target plate thickness.

When the target reduction position 31T is given by the reduction change device 10 and the reduction change instruction signal is given from the tracking device (TO), the above-mentioned AGC is stopped and the next target reduction position data Sl' is sent to the reduction control device 4. give an instruction to change the position of pressure. In response to this, the reduction control device 4 changes the reduction position at a speed set for itself. After that, when a change point signal is given from the tracking device 9 (the entrance side plate thickness change point has arrived), the above-mentioned gauge meter type %
The reduction control device adjusts the reduction position in the direction where the calculated value obtained by substituting the detected value P into the formula % becomes the target plate thickness! ! 4. Start AGC as instructed in step 4.

〔Effect of the invention〕

As described above with reference to FIG. 2, according to the present invention, off-gauge does not occur in the outlet side plate thickness at the plate thickness change point. Furthermore, the length of the exit side plate thickness variation portion at the plate thickness change point is shortened.

[Brief explanation of drawings]

FIG. 1 shows plate thickness control according to the present invention. A time chart showing the rolling position change timing and AGC on/off timing, and FIG. 2 is a time chart showing similar timing in the plate thickness control of the present invention at a predetermined plate thickness. FIG. 3a is a block diagram showing an overview of the configuration of an apparatus for carrying out one aspect of the present invention, and FIG. 3b is a block diagram showing the first to fifth devices shown in FIG.
FIG. 3C is a time chart showing the timing of changing the rolling position of the stand and changing the rolling speed. FIG. 3C is a flowchart showing an outline of the control operation of the arithmetic and control unit 23 shown in FIG. 3A. 1: Rolled material 2: Rolling machine 3: Reduction device 4: Reduction control device 5: Electric motor 6: Speed control device 7: Plate thickness change point detector 8: Pulse oscillator 9 Ni-tracking device 10:
Rolling change device 11: Speed changing device 12: Running schedule changing device 21: Rolling reaction force detector 22: Rolling position detector 23:
Arithmetic control unit 躬 4 国 郎 11 tOt, 14 No. 5 Ajo 2 Procedural Amendment (Method) March 5, 1985 Director General of the Patent Office Uga Michibe 1, Indication of Case Patent Application No. 206742 of 1988 issue
, →26 Title of the invention Plate thickness control method 3 during rolling plate thickness change during running, relationship to the case of the person making the amendment Patent applicant address 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name (665) New Japan Takeshi, Representative of Steel Corporation 1
) Yutaka 4, Agent 103 Telephone 0.3-864-6
052 Address 2-27-6 Higashi Nihonbashi, Chuo-ku, Tokyo
No. 53, date 7 of the correction order, the following sentence is inserted between lines 12 and 13 on page 10 of the statement of contents of the amendment. "Figure 4 is a time chart showing the rolling position change timing in conventional plate thickness control, and Figure 5 is the rolling position change timing and AGC on, in conventional plate thickness control.
It is a time chart showing off timing. "that's all

Claims (1)

[Claims] Before the plate thickness change point arrives, the rolling position change is started to a rolling position corresponding to the thickness of the rolled material after the change point, and when the plate thickness change point arrives, the rolling before the change point is started. The rolling position corresponding to the plate thickness of the material and the rolling position corresponding to the plate thickness of the rolled material after the change point Change the rolling position corresponding to the plate thickness change point at the timing and speed that the rolling position becomes the intermediate value or the rolling position before and after that. In rolling while changing plate thickness: At the start of the change in rolling position, the gauge meter type h=P/
During strip thickness change rolling during running, the AGC that controls the rolling position is stopped so that the outlet thickness estimated by M+50+Sh becomes the target thickness, and the AGC is started when the change point arrives. Plate thickness control method.