JPH0585251B2 - - Google Patents

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention relates to a tension correction automatic plate thickness control device,
More specifically, the present invention relates to a tension correction automatic plate thickness control device that corrects rolling load by paying attention to changes in tension on the front side and rear side of a rolled material during rolling.

(Conventional technology) Conventionally, in rolling equipment, in order to control the thickness of rolled material to a target thickness, absolute value
AGC (Automatic Gauge Control) has been used. The absolute value AGC is a control that predicts and calculates the steady-state rolling load in the rolling mill, sets the target plate thickness based on this, and controls the plate thickness to eliminate the difference between the target plate thickness and the actual plate thickness of the rolled material. It is.

FIG. 4 shows such a conventional automatic plate thickness control device. As shown in the figure, a rolling material 1 is rolled by a rolling mill 2. As shown in FIG. The rolling device 3 adjusts the gap between the upper and lower rolls 2a, 2a of the rolling mill 2. The roll gap S of the rolling mill 2 is delivered from the rolling device 3 to the automatic plate thickness control device 4. on the other hand,
The rolling load P is sent from the rolling load detector 5 to the automatic plate thickness control device 4. Upper and lower rolls 2 of rolling mill 2
The gap S between a and 2a is determined by the automatic plate thickness control device 4.
It is controlled by the rolling down device 3 in accordance with the control output ΔS from the plate thickness deviation Δh (see FIG. 5), which is the difference between the target plate thickness and the actual plate thickness. Gap adjustment of the rolling device 3 during rolling is performed by hydraulic pressure in view of high speed response and power.

Now, as mentioned earlier, the automatic plate thickness control device 4 receives the roll gap S from the rolling device 3 and the rolling load P from the rolling load detector 5, and its output is the control output ΔS (plate thickness The deviation Δh) is sent to the rolling down device 3 to perform plate thickness control using absolute value AGC. Here, the principle of absolute value AGC will be explained.

First, the exit plate thickness h of the rolling mill 2 can be determined by the following equation.

h=S+(P/M)(mm)...(1) S: Roll gap (mm) P: Rolling load (ton) M: Mill constant which is a constant specific to rolling mill 2 Second right side of equation (1) The term P/M is the amount of deflection due to the load of the rolling mill 2, and is a term called mill elongation.
For absolute value AGC, use equation (1) to calculate absolute value AGC.
Set the target plate thickness h _AB using equation (2).

h _AB = S _p + (P _AB /M) (mm) ...(2) S _p : Initial setting value of roll gap P _AB : Absolute value load (ton) For rolling load formula P _CAL , for example, (3) There is something like a formula.

P _CAL = B・K _p・(1−α・t _b + (1−α)・t _f /K _p )
_X√ ^′ _・( ⁻ )・Q _p Rear plate tension (Kg/mm ² ) t _f : Front plate tension (Kg/mm ² ) R′: Flat roll radius (mm) H: Inlet side plate thickness (mm) h: Compression side plate thickness (mm) Q _p : Thickness Lower force function Here, find the absolute value load P _AB from equation (3). From the rolling schedule, the rolling material width setting value B, material deformation resistance K _p , rear tension reference t _REF(i-1) , front tension reference
Since t _REFi , flattened roll radius R', entry side plate thickness reference H _REF , exit side plate thickness reference h _REF , and rolling force function Q _p are set, predictive calculation can be performed using these as shown in equation (4).

P _AB =B・K _P・(1−α・t _REF(i-1) +(1−α)・t _REF
i /K _P )X√′・(H _REF −h _REF )・Q _P X10 ^-3 (ton)…
...(4) h _REF = h _AB (mm) ...(5) Absolute value AGC performs plate thickness control to achieve the target plate thickness h _AB . Therefore, the plate thickness deviation Δh from the actual exit plate thickness h during rolling is calculated from equations (1) and (2) as follows: Δh=h _AB −h = {S _p + (P _AB /M)} − {S + ( P/M)} = (S _p - S) + {(P _AB - P)/M} = Δ _p + (ΔP/M) (mm) ...(6) ΔS _p = S _p - S (mm) ...(7) ΔP=P _AB −P(ton) ...(8) So that this plate thickness deviation Δh is "0",
By controlling the rolling down device 3, the target plate thickness is
h _AB can be obtained.

FIG. 5 shows a block diagram of the absolute value AGC section of the automatic plate thickness control device 4 shown in FIG. In the figure, a comparator 11 receives a roll gap S and a roll gap initial setting value S _p and outputs a roll gap deviation ΔS _p . On the other hand, comparator 12
inputs rolling load P and absolute value load P _AB , and sends out rolling load deviation ΔP. Mill elongation calculator 1
3 is calculated by multiplying the rolling load deviation ΔP by 1/M to obtain ΔP/
Send M. The adder 14 adds the output ΔP/M of the mill elongation calculator 13 and the output ΔS _p of the comparator 11 to obtain the plate thickness deviation Δh, and sends the result to the plate thickness control regulator 15. The plate thickness control regulator 15 multiplies the plate thickness deviation Δh by a gain (proportional integral gain) C for conversion to a gap and thickness control, and outputs the control output ΔS via a switch A that closes during rolling.
Sent as .

In this configuration, when the current roll gap S and rolling load P are input, the initial roll gap value S _p and the current roll gap S are input to the comparator 1 in order to obtain the roll gap deviation ΔS _p .
1 is compared. On the other hand, the absolute value load P _AB and the rolling load P are input to the comparator 12 in order to obtain the rolling load deviation ΔP. The mill elongation calculator 13 receives the rolling load deviation ΔP from the comparator 12 and outputs the mill elongation deviation ΔP/M. The elongation deviation ΔP/M of the mill is input to the adder 14 together with the roll gap deviation ΔS _p , and is added to obtain the plate thickness deviation Δh.
It is input to the plate thickness control adjuster 15 as follows. Here, the plate thickness deviation Δh is multiplied by a proportional integral gain G and output as a control output ΔS (mm). The effective period of this control output ΔS is the period during which contact A is closed during material rolling.

(Problems to be Solved by the Invention) FIG. 3 is an explanatory diagram of the rolling process, and the figure shows the (+1) stand ST ₊₁ of the tip 1a of the rolled material 1.
The figure shows the tip 1a of the rolled material 1 before it is bitten into the
After being bitten by (+1) stand ST ₊₁ ,
In the figure, the rear end 1b of the rolled material 1 is still (-1).
The figure shows a state where the rear end 1b of the rolled material 1 is stuck in the stand ST _-1 (-1).
Each shows the state after exiting ST _-1 .

In the state shown in Figure 3, the stand for the rolled material is
The forward tension t between ST and (+1) stand ST ₊₁ is zero. Next, proceeding to the state shown in the figure,
A front tension t is generated, but since tension control is being performed, the front tension t is near the front tension reference t _REFi . In other words, since there is a state transition between Fig. 3 and absolute value AGC, since the absolute value load P _AB in equation (4) is a constant value in the rolling steady state,
At the tip of the rolled material 1, an error occurs in the direction in which the plate thickness increases.

Similarly, the rear end of rolled material 1 is (-1) stand
In the state transition from FIG. 3 to ST _-1 , the rear tension t _-1 fluctuates, causing an error in the direction of increasing the thickness of the rear end portion 1b of the rolled material 1.

As described above, variations in the front and rear tensions at the leading and trailing ends of the rolled material 1 have a large effect on the plate thickness accuracy. On the other hand, even in the steady rolling section, even if rolling is performed near the tension standard due to tension control, the tension may deviate significantly from the tension standard due to changes in the properties of the rolled material 1, so in this case as well, the absolute value AGC The plate thickness accuracy will be reduced.

In recent years, the control plate thickness accuracy of rolling equipment is strict, ranging from a dozen microns to several microns, and moreover, this accuracy must be maintained over the entire length of the rolled material 1. Therefore, deterioration in plate thickness accuracy due to such tension fluctuations is fatal for equipment operation.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tension correction automatic plate thickness control device that can prevent deterioration in plate thickness accuracy caused by tension fluctuations at the front and rear ends of a rolled material during rolling.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a plurality of stands for rolling a rolled material by applying a rolling load, an arbitrary stand among the stands, and an upstream side adjacent to the upstream position and downstream position of the stand, respectively. tension detection means for respectively detecting the front inter-stand tension and the rear inter-stand tension of the rolled material between the stand and the downstream stand; and a predictive calculation of the front and rear inter-stand tension detected by the tension detection means. and rolling load correction means for correcting the rolling load of the arbitrary stand based on the deviation from the front and rear stand tension standards.

(Operation) The rolled material is rolled on an arbitrary stand. At that time, the tension between the front stands and the tension between the rear stands of the rolled material are detected by the tension detection means.
On the other hand, the tension reference between the front and rear stands is predictively calculated. The above tension between the front and rear stands,
The deviation from the tension standard between the front and rear stands is determined. The rolling load of the arbitrary stand is corrected based on the deviation. Thereby, the rolled plate thickness of the rolled material is adjusted.

(Example) Before describing the example of the present invention, the theoretical background will be explained.

The problem with conventional absolute value AGC is that since the absolute value load P _AB is a predicted calculated value in a steady state of rolling, an error occurs with respect to actual tension fluctuations. Therefore, instead of the absolute value load P _AB , it is sufficient to use the tension-corrected absolute value load P _AB ′ corrected by the tension variation.

The tension correction absolute value load P _AB ′ is determined as follows.

First, by differentiating equation (3) with respect to the front and rear tensions, an influence coefficient representing the degree of influence of each tension on the rolling load is formulated.

(∂P/∂t _b ) _i = −B√ _i ′・( _i − _i )・Q
_pi ^{_ _} _{_ _ _ _ _
pi} X10 ^-3 (ton/Kg/mm ² )...(10) Using these equations (9) and (10), correct the absolute value load P _AB of i-stand ST _i by the tension, and calculate the tension correction absolute Find the value load P _AB ′ using the following formula.

P _AB ′＝P _AB −(∂P／∂t _b )i・Δt _i-1 −(∂P／∂t _f )・Δt _i (ton) ...(11) t _i-1 = t _i-1 t _REF(i-1) (Kg/mm ² ) ……(12) Δt _i = t _i −t _REFi (Kg/mm ² ) ……(13) Equation (12) is the rear of i stand ST _i rear tension It is the deviation Δt ( _{i-1) from the tension standard (tension standard between rear stands) t REF(i -1)} , and equation (13) is the front tension standard (tension standard between front stands) of the front tension of i stand ST _i . The deviation from t _REFi is Δt _i .

By using the tension-corrected absolute value load P _AB ′ obtained by equation (11) instead of the absolute value load P _AB , for example,
(i+1) Since the forward tension t _i =0 at the tip 1a of the rolled material 1 until it is bitten by the stand ST _i+1 , (13)
The formula is Δt _i =−t _REFi (14). In addition, in (i-1) stand ST _i-1 , when the rear end 1b comes out, the rear tension t _i-1 = 0, so equation (12) is as follows: Δt _i-1 = -t _{REF(i- 1)} ……(15) and then make corrections due to tension fluctuations.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of a tension correction automatic plate thickness control device according to an embodiment of the present invention. The configuration in this figure is different from that in Figure 4. (i-1) A rear plate tension (tension between rear stands) detector 8 is installed between stand ST _{i-1 and} i stand
A front plate tension (tension between front stands) detector 7 is provided between ST _i and (i+1) stand ST _i+1 , and the detected value (rear tension) t _i-1 and the detection point (front tension) t _i The present invention is configured such that the tension correction automatic plate pressure control section 6 sends the information to the tension correction automatic plate pressure control section 6.

Figure 2 shows the tension correction automatic plate pressure control section 6 in Figure 1.
This is a block diagram showing the details of
This is the thigh showing the AGC section. In the same figure, the target load tension corrector 16 receives the detected values t _{i and} t _i-1 of the front plate tension detector 7 and the rear plate tension detector 8, and compares the tension correction absolute value load P _AB ′. The signal is sent to the device 12. The comparator 12 receives the tension correction absolute value load P _AB ' and the rolling load P, and outputs the rolling load deviation ΔP. The rest of the configuration is the same as in FIG. 5, and the same components as in FIG. 5 are given the same reference numerals.

1 and 2, the current roll gap S, rolling load P, front tension t _i and rear tension t _i-1 are input to the tension correction automatic plate pressure control section 6. . In order to obtain the roll gap deviation ΔS _p , a comparator 11 compares the roll gap initial setting value S _p with the current roll gap S, as shown in FIG. On the other hand, in order to obtain the rolling load deviation ΔP, the front tension t _i and the rear tension t _i-1 are input to the target load tension corrector 16, and the tension correction absolute value load P _AB ′ obtained by equation (11) is calculated. and output. Next, this tension correction absolute value load P _AB ' and the rolling load P are compared by the comparator 12, and the rolling load deviation ΔP is input to the elongation calculator 13 of the mill. The mill elongation calculator 13, which receives the rolling load deviation ΔP, outputs the mill elongation deviation ΔP/M to the adder 14, where it calculates the roll load deviation ΔP/M.
Add it to the gap deviation ΔS _p . As a result, the plate thickness deviation Δh is calculated and input to the plate thickness control adjuster 15. Here, the plate thickness deviation Δh is multiplied by a gain (proportional integral gain) for conversion to a gap and plate thickness control to obtain a control output ΔS. Note that the valid period of this output ΔS is while the contact A is closed.

Therefore, since the tension variation can be found using equations (12) and (13), by correcting the absolute value load P _AB and using it as the tension correction absolute value load P _AB ′ as shown in equation (11), A standard with few errors can be obtained. As a result, the control accuracy of the plate thickness h _i at the exit side of the i-stand ST _i is improved in the absolute value AGC, and it becomes possible to roll the plate material with high precision and high quality over the entire length of the rolled material 1.

〔Effect of the invention〕

According to the present invention, since the tension-corrected absolute value load corrected by the tension fluctuation is used instead of the absolute value load, the tension-corrected automatic sheet thickness makes it possible to improve the precision of sheet thickness control using absolute value AGC. A control device can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a tension correction automatic plate thickness control device according to an embodiment of the present invention, Fig. 2 is a block diagram of a tension correction automatic plate thickness control section in the apparatus of Fig. 1, and Figs. An explanatory diagram of the rolling process, FIG. 4 is an overall configuration diagram of a conventional automatic plate thickness control device, and FIG. 5 is a block diagram of an absolute value AGC section of the automatic plate thickness control device of FIG. 4. 1... Rolled material, 2... Rolling machine, 3... Rolling device, 5... Rolling load detector, 6... Tension correction automatic plate pressure control section, 7... Front plate tension detector, 8... Rear Plate tension detector, 11, 12... Comparator, 13...
...Mill's extension calculator, 14... Adder, 15...
Plate thickness control adjuster, 16...Target load tension corrector.

Claims (1)

[Claims] 1. A plurality of stands that apply a rolling load to roll the rolled material, and an arbitrary stand among the stands and an upstream stand and a downstream stand adjacent to the upstream and downstream positions thereof, respectively. Tension detection means that detects the tension between the front stands and the tension between the rear stands, respectively, and the deviation between the tension between the front and rear stands detected by the tension detection means and the tension reference between the front and rear stands that is predicted and calculated. A tension correction automatic plate thickness control device comprising: rolling load correction means for correcting the rolling load of the arbitrary stand.