JPS62156012A - Method and apparatus for controlling sheet tension in single stand multi-pass rolling mill - Google Patents

Abstract

PURPOSE:To exactly control the tension fluctuation of a strip at two points different with respect to the winding part or drawing out part of work rolls by determining the speed difference of the strip at said points. CONSTITUTION:The speeds at the respectively different two points of the strip S wound on the work rolls 2, 3 are detected by speedometers 7, 8, 10, 11 and speed signals V1, V2, V3, V4 are outputted to arithmetic units 9, 12 for tension. The deviations V2-V1, V1-V3 of the speed signals are determined and the tension fluctuation of the strip S is calculated in the units 9, 12. The tension value in the measurement stage is calculated by adding the tension fluctuation to the tension value in a reference state. The tension fluctuation of the strip S at every specified time interval is proportional to the speed difference of the strip S at the respective points of the time between the two points in this case. The output differences of the detectors 7, 8, 10, 11 are, therefore, determined without calculating the tension fluctuation in order to stabilize the tension of the strip S wound on the rolls 2, 3. The speeds of the rolls 2, 3 are then controlled in accordance with the signals thereof, by which the tension fluctuation is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for controlling plate tension in a one-stand multi-pass rolling mill.

[Prior Art] Recently, as shown in FIG. 4, R D (R
ol l ing drawing) rolling method was developed, which made it possible to significantly reduce the rolling load, making it possible to downsize the rolling mill, reduce roll wear, roll hard materials such as high-strength steel, and reduce edge drop. ing.

Furthermore, as an improvement to the RD rolling method, as shown in Fig. 5, strips S are wound around work rolls a, b, c, and d arranged in multiple stages, and each work roll a, b is rolled.

A rolling mill has been proposed in which rolls c and d are rotated at different circumferential speeds and rolled down by backup rolls e and f, thereby performing multi-pass rolling in one stand. This rolling mill has the advantage that high reduction rolling is possible with a low rolling load and that the rolling mill can be further downsized.

However, in the above-mentioned rolling mill, the tension of the strip S on the exit or entry side of each pass may change during rolling, and if the tension becomes abnormally high, the strip S may break and cause damage to the work rolls a, b, c, and d. If the strip S is scratched or the tension on the entry side is low, the strip S will meander, and if the tension on the winding part is low, the plate thickness will change or the strip S will fold and get caught in the roll gap and rolled. This causes so-called narrowing down. Conventionally, rolling mill entry side (first pass rear tension)
Although there was a method to measure the output side (third pass forward tension),
There was no way to measure the tension in the winding of the strip S on the work rolls b and c in FIG. 5.

[Problems to be Solved by the Invention] Therefore, conventionally, the above-mentioned winding of the strip S cannot accurately control the tension of the part, and as described above, the roll cap of the work roll gap and the roll of the work roll gap Plate breakage and squeezing occurred frequently in the gap.

In view of the above-mentioned circumstances, it is an object of the present invention to provide a means for detecting tension fluctuations in a strip wound on a work roll, so that accurate control of the strip tension in the work roll winding section can be carried out. This makes it possible to prevent plate breakage, constriction, etc.

[Means for Solving the Problems] In the present invention, three or more work rolls are provided, and a strip is passed between opposing work roll gaps, and the strip is fed from one work roll gap to another work roll gap. In a one-stand multi-pass rolling mill in which the strip is wound around a work roll or pulled out before and after the work roll, the speed of the strip is measured at two different points at the work roll winding section or at the drawing section, and the The speed difference of the strip at the work roll winding section or the pull-out section is determined from the speed, and control is performed so that this speed difference becomes zero based on the state where stable rolling is being performed.

[Function] Therefore, in the present invention, the speed of the strip is measured at two different points with respect to the work roll winding section or the drawing section, and
By determining the speed difference, it is possible to control strip tension fluctuations in that area.

[Example] Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention, in which a one-stand three-pass rolling mill is used. In the figure, 1.2 and 3.4 are work rolls, 5 is a lower backing roll, and 6 is an upper backing roll, and the strip S passes through the roll gap between the work rolls 1.2 and 2. wrapped around the work roll 2,
It is wound around the work roll 3 through the roll gap between the work rolls 3 and 4, and is sent to the downstream side of the rolling mill through the roll cap between the work rolls 3 and 4.

A non-contact speed detector 7.8 is provided on the front surface of the work roll 2 to measure the speed at two different points of the strip S wound around the work roll 2. Based on the speed signals @Vl and V2 detected at 8, the tension calculation device 9 calculates the strip S wound around the work roll 2.
The tension can be calculated. Further, a non-contact speed detector 10.11 is disposed on the rear surface of the work roll 3 to measure the speed at two different points of the strip S wound around the work roll 3. .1
Based on the speed signals V3 and V4 detected in 1, the tension calculation device 12 calculates the strip S wound around the work roll 3.
The tension can be calculated.

As the non-contact type speed detectors 7, 8, 10.11, for example, there are those that utilize the laser Doppler effect, and it is possible to measure the strip speed with high accuracy.

During rolling, after the strip S is passed as shown in FIG. 1, presets such as predetermined roll gap settings and tension settings are performed, and then rolling is started.

The speeds at two different points of the strip S wound around the work rolls 2 and 3 are detected by the speedometers 7,8,10°11, and the speed signals V+, V2, V3 are obtained.

V4 is output to tension calculation devices 9 and 12.

Now, the tension fluctuation of the strip S when it is wound around the work roll 2 is ff1T+ = + f (V2-Vl > d↑
...(i), the tension fluctuation aT2 of the strip S at the part where it is wrapped around the work roll 3 is
1 = to 2 f (V4-V3) d t...(i
Since it can be obtained by i), the tension calculation devices 9 and 12
Then, find the deviation V2 Vl, V4-V3 of the speed signal,
(i) The tension fluctuation aTi of the strip S is determined by equation (ii)
, Al1 are calculated. (i) (n) + in formula, 2
is a constant determined by the cross-sectional area of the strip S, Young's modulus, etc.

By the way, this winter, the output from the speed detector 7, 8, 10, 11 was sampled at a fixed time interval At, and (i) (-)
When calculating the equation, the tension fluctuation AT+, Al1 becomes +' Akane for AT+ =, (V2H-VB>ff1t= +'ffl ti!, 1(V2HVll) - (m7
1IT2=2',%1(V4HV3H) IJ t=
2'Ath1(V41-V31)...Ov). Then, the tension variation of the strip S at each point in time is ``1i,''
Looking at T2i, A TH = K 1' (V2HVB) A t = A
+ (V2HVH) =A1Av11...(v)A T
21=K2' (V4HV3H) A t=A 2
(V 4 + V 3 H>=A2AV21
...It becomes 6/D. That is, the tension variation AT1 of the strip S at regular time intervals. ．． aT2. is found to be proportional to the difference in velocity of the strip S at each point in time between the two points. Therefore, in order to stabilize the tension of the strip S wound around the work roll 2.3, (+) (r+)
Tension fluctuations AT+ and aT2 can be eliminated by calculating the output difference of the speed detectors 7, 8, 10, and 11 and controlling the speed of the work roll based on the signal without calculating the tension fluctuations AT+ and Al1 using the formula. Is possible.

This is possible, for example, by utilizing the fact that the intermediate tension changes as shown in FIG. 2 when the speed of each work roll is changed. In addition, A+, A2, +'# K2
' is a constant.

FIG. 3 shows a further embodiment of the present invention based on the above principle. In the figure, 13.15 is the electric motor that drives the work roll 1.4, 14.16 is the electric @13.15 speed detector, 1
7.19 is a comparison calculator for calculating the speed deviation of the strip S detected by the speed detector 7, 8.10.11, 18.2
0 is a speed control device that controls the rotational speed of the electric motors 13.15 based on the speed deviation signal from the comparator 17.19 and the speed signals of the electric motors 13 and 15 from the speed detector 14.16. Further, although the work rolls 2 and 3 are not shown, they are driven by an electric motor.

Comparison calculators 17, 1.9, speed detectors 7, 8.10
The work roll with 2.3 windings detected at ゜11 is based on the speed signal of ゜11=V21-V11,
AV2i-v4i"3i is determined, and the speed deviation signal AV1..AV2H is outputted to the speed control device 18.20. Based on this, the speed deviation signal AV1..AV2H is output to the speed control device 18.
A command signal is output to electric @13.15, and a speed deviation signal ff1V1. , AV2. The rotational speed of the electric motor 13, 15 is controlled so that the rotational speed becomes zero. Electric motor 13°15
The rotational speed of is detected by a speed detector 14.16, compared with a predetermined value by a speed control 1aTI device 18.20, and feedback control is performed to reach that value.

Speed deviation signal AV1. ．． '13V2. In the case of zero, the tension at the part where the strip S is wrapped around the work roll 2 and 3 is kept constant and there is no tension fluctuation.

In the embodiments of the present invention, the case where the strip is wound around the work roll has been described, but the so-called so-called case where the strip is pulled out before and after the work roll without being wound around the work roll and rolling is performed between the work roll gaps is described. It goes without saying that the present invention can be applied to draw rolling, that any number of passes can be performed in one stand, and that various changes can be made without departing from the gist of the present invention.

[Effects of the Invention] According to the method and device for controlling plate tension in a one-stand multi-pass rolling mill of the present invention, the speed of the strip is measured at two points at the strip winding section or the pull-out section. It is possible to easily determine the variation in strip tension in the section, and therefore, by controlling the variation in strip tension, troubles such as plate breakage and narrowing can be easily prevented.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention, and FIG. 2 is a graph showing that the intermediate tension changes when the different speed rate of each pass is changed.
FIG. 3 is an explanatory diagram of another embodiment of the present invention, FIG. 4 is an explanatory diagram of the RD rolling method, and FIG. 5 is an explanatory diagram of the conventional one-stand multi-pass rolling technique. In the figure, 1.2, 3.4 are work rolls, 7, 8, 10.1
1 is a speed detector, 9 and 12 are tension calculation devices, 13.15
17.19 is a comparator, and 18.20 is a speed control device. Figure 2 2 Ba Z-eye trap Liaoyu ×2 Figure 1 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1) Three or more work rolls are provided, the strip is passed between opposing work roll gaps, and the strip sent from one work roll gap to another work roll is wound around the work roll. In a one-stand multi-pass rolling mill in which the strip is attached or pulled out before and after the work roll, the speed of the strip is measured at two different points with respect to the work roll winding part or the pull-out part, and the work roll winding part is determined from the speed. Alternatively, a plate tension control method comprising determining the speed difference of the strip at the pull-out section, and controlling the strip tension variation amount at the strip winding section or the pull-out section to be small based on the speed difference. 2) Three or more work rolls are provided, and the strip is passed between opposing work roll gaps, and the strip sent from one work roll gap to another work roll is wound around the work roll or A non-contact speed detector for detecting the speed of a strip at two different points relative to a work roll winding section or a pull-out section in a one-stand multi-pass rolling mill that is pulled out back and forth, and the speed detector A device is provided for determining the speed difference of the strip at the strip winding section or the pull-out section based on a signal from the strip winding section or the pull-out section, and controlling the strip tension fluctuation amount at the strip winding section or the pull-out section to be smaller based on the speed difference. Plate tension control device.