JPS5837368B2 - Slab position adaptive control method - Google Patents

Description

Detailed Description of the Invention A heating furnace is a facility that reheats a slabbed slab rolled at a blooming factory or a continuous cast slab continuously cast to the target temperature for rolling in the hot rolling process. The slab is transported to the front of the heating furnace using a full-throttle and loaded into the furnace using a pusher or walking beam.

After that, the movable skid repeatedly moves in a rectangular motion to transport the slab to the extraction port and heat it up to the target extraction temperature.At this time, the temperature of the part of the slab in contact with the fixed skid is lower than that of other parts, and this is the reason why the material is rolled after extraction. It also influences the process.

This is called a skid mark, and because the temperature is low, the deformation resistance increases, causing plate thickness fluctuations.

Naturally, this skid mark is determined by the position of the slab when charging it into the heating section, but the conventional method of charging slabs into the heating furnace was determined solely from an operational standpoint. , the length from the tip of the slab to the fixed skid is not actively considered.

Therefore, the position from the tip of the strip where skid marks appear after rough mill rolling or finish mill rolling varies, and it is impossible to achieve a constant length using conventional charging methods.

This actually has the following negative effects.

1) During the so-called threading process in which the leading edge of the material is bitten by the first stand and then bitten by the last stand in the finishing mill, skid marks may appear along the way, and this is simply due to the deformation resistance of the skid mark part. This causes not only the adverse effect of plate thickness errors due to the large thickness, but also an even worse effect.

In other words, during sheet threading, it is an unstable state even during finish rolling, and the inter-stand tension control device such as a looper is activated every time each stand board is engaged, and the tension control is performed to establish the target tension. At this time, if there is a part that causes thickness disturbance such as skid marks, it is usually called Visla (
The plate thickness control system (BISRA) type AGC also operates aggressively, causing interference with the tension control system mentioned above, resulting in lower control performance for plate thickness accuracy, plate shape, etc. compared to the case without skid marks. It is unavoidable to do so.

2) In recent years, process computers have been introduced in most of the hotspot l-IJ mill controls, and setup calculations are performed using mathematical models, but this mathematical model is usually adapted and modified by collecting actual rolling performance data. is being applied.

The timing of this data collection is usually a point at a certain length from the tip of the finished plate, or at the tip, center, rear end, etc.
Since the data is collected at pre-specified points and the data is not particularly actively avoided in the skid mark area, or conversely data is collected in the skid mark area, the abnormal data causes adaptive corrections to be made and the setup will be changed from next time. There were cases where it affected the

The object of the present invention is to perform slab position control that is effective in solving these problems, and specifically, to control the stop position of the slab so that skid marks appear at a predetermined position from the tip of the slab. An object of the present invention is to provide a position adaptive control method.

If the point at which the skid mark appears can be controlled to a fixed position from the tip of the slab, then the adverse effect 1) caused by the conventional charging method described above can be avoided by loading the slab at a position where the skid mark does not reach when passing through the finishing rolling mill. It is also possible to enter

In addition, regarding the negative effect 2) due to the charging of the conventional method, if the position where the skid marks appear can be controlled,
It is possible to check in advance where the skid mark is located from the tip of the board in terms of finished length, and it is also possible to actively collect data on the skid mark area.
It is also possible to collect data that avoids the skid marks.

In this invention, when setting the stopping position of the slab at which position to stop the slab with respect to the fixed skid position, in order to make this setting more accurate, the actual skid marks of the slab extracted from the heating furnace are used. Find the position that has appeared, find the adaptive correction amount for the stopping position of the slab charged into the heating furnace based on this actual value, and use this adaptive correction amount to set the stopping position of the new slab charged into the heating furnace. Let's do it.

Hereinafter, the present invention will be explained in detail based on specific examples.

FIG. 1 shows an embodiment of the present invention.

In this figure, 1 indicates a heating furnace and 2 indicates a slab.

The slab 2 transported by the transport table 14 is loaded into the heating furnace 1, heated there, and then extracted from the heating furnace.

A material position detector (MD) 3 outputs a detection signal when the tip of the slab 2 reaches the installation position of the detector 3.

A thermometer 4 detects the surface temperature of the slab 2' extracted from the heating furnace 1 and being transferred.

5 is a material position detector ( }TMD), which detects the slab 2
When the tip of ' reaches the installation position of the detector 5, a detection signal is output.

6 is a rough rolling mill.

7 is a speed detector that detects the speed of the transport table 14.

11 is a speed detector that detects the slab speed.

Reference numeral 9 denotes a conveyance table control device, into which the slab stop position set value LX is input, and the slab 2 is moved to the set position (L x
) and stop it.

Reference numeral 8 denotes a slab stop position calculation device, which calculates the slab stop position set value LX, and uses the detection signal (timing) of the material position detector 3 to convert the set value LX to the conveyance table control device 9.
Output to.

10 indicates a calculation device, which calculates the length i from the tip of the strip to the position where the skid mark should appear in terms of target length.
t, slab thickness Ho, and slab width b.

, target plate thickness hF, target plate width bF to slab conversion length,
{Calculate L.

This AL is the target length from the tip of the slab to the skid mark generation position.

12 is the actual skid mark position (actual value of the length from the tip of the slab to the point where the skid mark appears) JLA
This is a skid mark position detection device that detects skid marks.

13 is an exponential smoothing calculator.

15 is a storage device. 17 indicates a subtractor.

The slab stop position calculation device 8 in the conventional method requires the slab length L to calculate the slab stop position set value Lx.

The distance between the fixed skid and the tip of the slab is α (=
The length from the tip of the slab to the point where skid marks appear) was arbitrary.

In the present invention, the slab position is controlled so that this distance α becomes a predetermined value.

In the embodiment shown in FIG. 1, the above-mentioned At, Ho, bo, hF,
The target length JL is obtained using bF.

In this embodiment, <JL is determined so that the length it from the tip of the rolled material (strip) to the skid mark occurrence position is kept constant after rolling.

That is, it is determined by the following formula. , {E=hF' bF.
i”Z ・・・・・・・・・・・・・・・・・・
(1) Ho-bo The calculation of equation (1) is performed by the calculation device 10.

The arithmetic device 10 that has received the setting input data 16 (data necessary for the calculation of equation (1)) performs the calculation of equation (1) and provides this {L to the arithmetic device 8.

Note that this JL is stored in the storage device 15.

The slab stop position calculation device 8 calculates this target value, {L
is used to calculate the slab stop position setting position LX, and the Lx is given to the conveyance table control device 9 at the timing from the material position detector 3.

The conveyance table control device 9 forms a minor loop automatic control system with the table speed detector 7, and stops the slab loaded into the heating furnace at the set value LX according to the command from the slab stop position calculation device 8.

The slab charged into the heating furnace is heated and eventually extracted from the heating furnace 1.

The skid mark position of the slab extracted from the heating furnace is confirmed by a skid mark position detection device.

Here, the skid mark detection device utilizes the property of the temperature drop of the slab at the skid mark position (1) direct measurement with a thermometer, (2) taking into account the increased deformation resistance of the slab. Although there are methods such as indirect measurement using a load meter, in the embodiment, as an example, a device using a thermometer 4, an HMD 5, and a detection signal from a material speed detector 11 is shown.

A concrete explanation of this is as follows.

That is, when the tip of the slab 2' reaches the installation position of the HMD 5, the HMD 5 outputs a signal.

When the skid mark position detection device 12 inputs this,
The speed detection signal of the material speed detector 11 is input and integrated.

This integration is continued until the detection signal of the thermometer 4 has significantly decreased.

The integrated value at that point is the detected value of the actual skid mark position.

In this manner, the skid mark position detection device 12 measures the skid mark position, that is, the actual position ALA of the skid mark from the tip of the slab.

In that case, the search range LsR is JL-ε<LsR<JL+ε...
...(2) ε: minute length, which facilitates measurement and confirmation of ALA.

The subtracter 17 calculates the actual skid mark position detection value ALA.
and the JL set by the arithmetic device 10 is stored in the storage device 15.
The deviation is calculated as follows.

δA2AL−, {LA ・・・・・・・・・・・・
(3) Furthermore, the exponential smoothing calculator 13 calculates the correction amount δ from the deviation δA in equation (3) using the well-known method shown below.

This is fed back to the calculation device 10 for position control of the next slab.

In other words, when calculating [, for the next slab, its δ
Perform adaptive correction using .

This allows a better slab stopping position to be determined.

In FIG. 1, the embodiment of the present invention has been described based on an apparatus, but a part of this embodiment can be implemented using a computer.

FIG. 2 shows a flowchart of arithmetic processing when the portion indicated by the two-dot chain line in FIG. 1 is executed by the computer 100.

This FIG. 2 will be explained next.

When the slab 2 is placed on the transport table 1, the data for the JL calculation for the slab 1 is transmitted from the host computer (not shown) to the computer 100 and stored in the internal memory.

In FIG. 2, the processing up to this point is not shown.

After this storage, the computer 100 starts the process shown in FIG.

That is, in step F1, the above-mentioned equation (1) is calculated, and the result JL is stored in the internal memory (
Processing of step F2).

Subsequently, the computer 100 calculates the slab stop position setting value LX (processing of step F3).

After this calculation, when the tip of the slab 2 reaches the position where the detector 3 is installed (step F4), the set value LX is output to the control device 9 (processing of step F5).

When the slab 2' extracted from the heating furnace reaches the installation position of the HMD 5 (step F6), the skid mark position detection operation is started (step F7).

When the skid mark position is detected in step F7, the process proceeds to step F8, where the error δA between the actual value and the set value is determined.
is calculated.

In step F9, except when this error is very small, the correction amount δ is calculated using this error δA (step FI
O) L, store this result in the internal memory (processing of step F11).

This stored correction amount δ is used in the next calculation (step F
3 processing) (This is used.

In this way, the adaptive correction amount δ is calculated and stored in each calculation, and this is used in the next calculation to obtain a more accurate set value Lx, thereby achieving highly accurate slab position control. can be realized.

As described above in detail, according to the present invention, the slab stopping position can be controlled with high precision so that the skid mark appears at a predetermined position from the tip of the slab.

[Brief explanation of the drawing]

1 and 2 are drawings showing one embodiment of the present invention. 1...Heating furnace, 2...Slab, 3...
...Material position detector, 4...Thermometer, 5.
...HMD, 6...Roughing mill, 7...
...Speed detector, 8...Slab stop position calculation device, 9...Transport table information {] control device, 10
... Arithmetic device, 11... Speed detector,
12... skid mark position detection device, 13.
...Exponential smoothing calculator, 14...Transfer table, 15...Storage device, 16...Setting input, 17...Subtractor.

Claims (1)

[Claims] 1 Set the length from the fixed skid position of the slab heated in the heating furnace to the tip of the slab in the rolling direction at the time of charging the furnace,
Load the slabs into the furnace so that they are at the set positions, store the set values for each slab, and after extracting the slabs, detect the length from the tip of the slab to the position where skid marks occur. . A slab position adaptive crushing method characterized in that an adaptive correction amount is obtained using the difference between the detected length and the stored setting value, and the adaptive correction amount is used in calculation for the setting.