JPH04100623A - Method for slowing down automatically on cold reversing roll mill - Google Patents

Abstract

PURPOSE:To improve the yield for the sheet by caluculating the slowdown command value of the inlet side sheet speed due to the remaining lapped amount of the rewinding reel, and correcting the slowdown command value for the mill with the difference of the actual measurement value of the inlet side sheet speed. CONSTITUTION:The lapped number of the sheet on the reel 2 is caluculated with the lapped number calculator 12 by detecting the rotating speed of the motor 6 for the rewinding reel of the rewinding reel 2 with the speed detector 11. When the lapped number reaches the prescribed number, the output of the comparator 21 is inputted to the speed command caluculator 13 and the slowdown command is outputted to the mill motor 5 of the mill 1. Because if the mill 1 is slowed down, the backward slip is changed, so in order to correct this, the correcting signal is given to the speed command caluculator 13 for the mill by actually measuring the inlet side sheet speed with the speed detector 9 of the deflecter roll 4, and outputting the difference through the subtractor 35 with the inlet side speed slowdown controller 34. The accuracy of the remainder coil length on the reel is improved, and the yield for the sheet is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic deceleration method for a reversible cold rolling mill to which lap count automatic deceleration is applied.

[Conventional technology]

FIG. 4 is a block diagram showing the drive system and control system of a conventional cold rolling mill. In the figure, 1 is a rolling mill, 2 is an unwinding reel, 3 is a take-up reel, 4 is a deflation crawl,
5 is a mill motor, and 6 is a rewinding reel motor. The rotational speed of the mill motor 5 is detected by a speed detector 7 such as a pulse generator, and converted into a mill speed υ by an F/υ converter 8. The rotational speed of the deflation crawl 4 is also detected by a speed detector 9 such as a pulse generator, and the inlet plate speed υ is detected by an F/v converter 10.
Converted to In. Furthermore, the rotational speed of the rewinding reel motor 6 is determined by a speed detector 1 such as a pulse generator.
1, and the wrap number N of the plate on the rewind reel 2 is calculated by the wrap number calculator 12. In addition, 1
3 is a speed command calculator, 14 is a mill speed controller, and 15 is a drive device for the mill motor 5.

Next, a conventional method will be explained.

When the number of wraps on rewind reel 2 is N, the length of the coil remaining on reel 2 is, , is obtained by (1) formula % formula % (
1) Here, Do: Coil inner diameter (rewind reel outer diameter) a: Inlet side plate thickness This calculation is performed by the coil length calculator 16 in FIG. 4.

n when deceleration is completed. If we calculate the remaining strip length until the deceleration is completed assuming that only the turn is left on the reel, Lpo = (πD(lnO+πano)) ・・
...=(2). This calculation is performed by the subtracter 18 in FIG. 4, and the calculation of the second term on the right side of equation (2) is performed by the calculator 17.

Next, find the distance β that the IJ knob travels while being decelerated from IJlh to v1□0. v In ”””(3)(“,
°α,. =α −−mu) However, α1. : Entry side deceleration α : Mill deceleration V : Mill speed. This calculation is performed by the mileage calculator 19 shown in FIG.

When performing automatic deceleration, remaining strip length until deceleration is completed ≦ Length of traveling during deceleration l ・・・・・・・・・・・・(4
) is satisfied, deceleration can be started. therefore(
From equations 2), (3), and (4), the deceleration start time is:
Lpoi (πDono +7r ano2)
≦ ,, (v,, : )・・・・・・・・・
(5) is established. This is done by calculating the difference between the spear and L by the subtractor 20 in FIG. 4 and by comparing the difference by the comparator 21. , and generates a deceleration command signal to be given to the mill motor 5.

In the cold rolling mill, since rolling is performed by the mill 1, the speed of the mill 1 is faster than the entrance plate speed. Therefore, when decelerating, the inlet side starts decelerating from a speed lower than the mill speed, as shown in FIG. During deceleration, the mill speed V and the entrance plate speed V
1. ．． The ratio of the difference in to the mill speed (reverse rate: (v-v
When V)/V) is always constant, when the mill in the speed mask is decelerated in a straight line as shown in ■ to the deceleration completion point a, the speed on the inlet side is also decelerated in a straight line as shown in ■.

In conventional rolling mills, automatic deceleration is started when the remaining length of the coil on the unwinding reel becomes shorter than the plate length of the coil running during entry side deceleration, assuming that there is no change in the backward movement rate during deceleration. The speed of the mill was reduced in a straight line as shown in ■.

[Problem to be solved by the invention]

However, when the mill is decelerated in a straight line, the backward rate is not kept constant, and as shown in Figure 3, the actual speed at the entrance of the mill is
The speed changes as follows, and there is a speed difference from the straight line (■) when the reverse rate is constant. This is because the rolling conditions such as the friction coefficient of the mill change when deceleration starts, and the backward movement rate changes.

As a result, when the mill deceleration is completed, a plate running length error shown by diagonal lines in FIG. 3 occurs, and the accuracy of the remaining length after deceleration is degraded. In the case of a rolling mill with a high rolling speed, this error becomes especially large, and if the remaining length after deceleration is set short, the tail end of the plate may come off the unwinding reel during deceleration, or
On the other hand, when deceleration is complete, too much plate remains, which sometimes lengthens the time required for low-speed driving to stop.

Therefore, an object of the present invention is to improve the accuracy of the remaining length of the coil on the rewinding reel at the time of completion of deceleration.

[Means to solve the problem]

The automatic deceleration method for a reversible cold rolling mill of the present invention is based on the calculation result of the remaining wrap amount of the unwinding reel and the deceleration on the entrance side from the start of automatic deceleration in the lap count automatic deceleration method of the cold rolling mill. It calculates the speed deceleration command value, inputs the difference signal between the measured value of the entrance plate speed and the input side deceleration speed controller, and uses the output to correct the mill deceleration command value of the mill speed command calculator. shall be.

[Effect]

By the above means, it is possible to improve the accuracy of the length of the remaining coil on the unwinding reel at the end of deceleration, and prevent the tail end of the plate from coming off the reel during deceleration, or the length of the remaining tail end being too long, resulting in longer rolling time. Prevents stretching.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples.

FIG. 1 is a block diagram showing a configuration for implementing the method according to the present invention.

In the same figure, those having the same functions as the conventional blocks shown in FIG. 4 are given the same reference numerals, and the explanation thereof will be omitted.

The difference between the present invention and the conventional method is that the entry side deceleration calculator 31. Entry side slow speed command calculator 32. Closed contact during deceleration 33. An inlet side deceleration speed controller 34 and a subtractor 35 are provided to correct the mill deceleration command value.

In other words, at the start of deceleration, equations (2) and (3)
From the formula, ......(6) holds true. If the relationship expressed by equation (6) is maintained at all times during deceleration, no turns will remain as desired at the end of deceleration. The entrance speed at this time is v in from equation (6).
=2αill LPOR−(πDOnO+πano
')+1'lno''/2α1...(7
). Here, αl, , is calculated from the previous sampling value IJiゎ, -1 of the speed detector 9 attached to the deflector roll 4 to detect the entrance speed and Δ from the subsequent current sampling value V8 using the following formula. .

υ −V −・・・・・・・・・(8〕α1.=
A speed standard for the entrance plate speed is created by the entry side deceleration calculator 31 and the entry side board speed command calculator 32 that calculate the equations Δt (7) and (8). In order to reduce the speed according to this speed standard,
The subtractor 35 calculates the difference between the input plate speed actually measured by the speed detector 9 and sends a correction signal to the mill's speed command calculator 13 via the deceleration gate contact 33 and the output of the input deceleration speed controller 34. give. The entry side deceleration speed controller 34 is constituted by a proportional controller or a proportional/integral controller.

By the above correction, the deceleration rate of the plate speed on the entrance side of the mill is kept constant despite changes in the backward movement rate, and the accuracy of the remaining coil length on the unwinding reel 2 at the time of completion of deceleration is improved.

〔Effect of the invention〕

As described above, according to the present invention, even if the backward movement rate of the plate changes during deceleration, the length of the remaining coil on the unwinding IJ-ru when deceleration is completed can be controlled to be constant, This prevents the tail end of the reel from coming off the reel during deceleration, damaging the board or machine, or conversely, preventing too much board from remaining at the end of deceleration, prolonging the low-speed running time until it stops. Furthermore, since the deceleration completion length can be set short, the start timing of deceleration, which is a major factor in increasing plate thickness deviation, can be delayed, which also contributes to improving the yield of plates.

In addition, in the case of a reversible rolling mill, in order to prevent the unrolled part at the end of the plate surface from being rolled when the rolling is stopped in the subsequent pass and the plate breaks, etc., the stopping position is shifted little by little, and the unrolled part is stepped up. However, by applying the present invention to a deceleration method from a gradual speed, that is, a deceleration completion speed to a stop, stopping accuracy can also be improved. This shortens the unrolled portion and improves yield.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment to which the method according to the present invention is applied, Fig. 2 is a time chart explaining the entry side deceleration pattern, and Fig. 3 shows the error between the actual entry side deceleration curve and the deceleration length. The time chart and FIG. 4 are block diagrams for explaining the conventional automatic deceleration method. 1: Mill 2: Rewind reel 3: Take-up reel 4: Deflation crawl 5: Mill motor
6: Motor 7. 9, 11: Speed detector 8, 10: F/v converter 12 Niratub computing unit 13: Speed command computing unit 14:
Mill speed controller 15: Drive device 16: Coil length calculator 17: Arithmetic unit 18, 20.35: Subtractor
19: Travel distance calculator 21: Comparator 31: Entrance side deceleration calculator 32: Entrance plate speed command calculator 33: Deceleration middle gate contact 34: Entrance side deceleration speed controller

Claims (1)

[Claims] 1. In the lap count automatic deceleration method of a cold rolling mill, from the start of automatic deceleration, a deceleration command value for the inlet plate speed is calculated from the calculation results of the remaining lap amount of the unwinding reel and the inlet deceleration, and the inlet plate speed is calculated. An automatic deceleration method for a reversible cold rolling mill, characterized in that a difference signal between the measured value of