JPH04305305A - Method for controlling elongation percentage of skinpass rolling mill - Google Patents

Abstract

PURPOSE:To make the length of poor elongation percentage part at the unsteady time of acceleration or deceleration time as shorter as possible. CONSTITUTION:When the elongation percentage is in a set range, tension is fixed and elongation percentage control by rolling load of skinpass rolling mill 3 is executed. When the elongation percentage is out of the set range, rolling load is fixed and also the elongation percentage control is executed by changing the speed of bridle rolls on the inlet and outlet sides.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to elongation control during temper rolling of strips such as cold-rolled steel sheets, and particularly during acceleration/deceleration or when changing the elongation setting value after rolling. The present invention relates to an elongation rate control method that allows the elongation rate to be obtained with high accuracy.

0002

[Prior art] The elongation rate of cold-rolled steel sheets etc. by a temper rolling mill is usually controlled by tension control with bridle rolls installed on the entry and exit sides of the temper rolling mill, and by the rolling load of the temper rolling mill. Control is also carried out. For example, in order to keep the elongation rate constant even during unsteady conditions such as acceleration and deceleration,
A technique as shown in Japanese Patent No. 275514 has been developed.

[0003] The technique disclosed in JP-A No. 62-275514 determines in advance the amount of rolling load correction corresponding to the speed change, corrects the rolling load at the same time as the speed change occurs, and This is to keep the elongation rate constant while keeping the tension on the exit side stable.

0004

[Problems to be Solved by the Invention] However, in the case of temper rolling mills, the rolling speed is generally slow, and the reaction to normal rolling load is about 1 to 2 seconds/100 tons, and the effect of rolling load on elongation is low. Because it is small, the elongation rate often deviates from the set value during unsteady conditions. On the other hand, control using tension has the problem of affecting surface quality and deterioration of shape due to narrowing, etc., and it has been considered that it cannot be changed too much.

[0005] Therefore, with the above-mentioned conventional technique of correcting the rolling load while keeping the tension stable, the elongation control by changing the rolling conditions may not be able to follow the change in the elongation, resulting in a problem in that the portion with poor elongation becomes long. It became. This problem is especially serious during unsteady conditions such as acceleration and deceleration. The present invention has been made in order to solve the above-mentioned problems in the conventional technology, and it is an object of the present invention to provide a method for controlling the elongation rate of a temper rolling mill with high accuracy even during non-stationary conditions such as during acceleration and deceleration. .

[0006]

[Means for Solving the Problems] The present invention is a method for controlling the elongation rate of a temper rolling mill in which bridle rolls are arranged on the inlet and outlet sides, and is applicable when the elongation rate after rolling is within a set range. The tension is kept constant and the elongation rate is controlled by the rolling load of the temper rolling mill, and when the elongation rate is out of the set range, the rolling load of the temper rolling mill is kept constant and the bridle roll is controlled. The speed is changed to control the elongation rate, thereby solving the above-mentioned problems in the conventional technology.

[0007]

[Operation] First, when the elongation rate after rolling is within a set range, the tension is kept constant and the elongation rate is controlled by the temper rolling mill. When the elongation rate control is stable in this way, the rolling operation is also relatively stable, and even if the rolling speed is a little slow, there is no problem, and the elongation rate of the rolling load is If the influence of

Next, when the elongation rate is out of the set range, the elongation rate is controlled by keeping the rolling load constant and changing the speed of the bridle roll. In the case of temper rolling, since the reduction ratio is small, there is some leeway in the effect of the above-mentioned tension change on the surface quality and shape. Therefore, in the present invention, when the elongation rate is out of the set range, the speed of the bridle roll is changed so that the tension that immediately responds to the elongation rate is controlled to quickly return the elongation rate to within the set range.

In the present invention, when the elongation rate control is stable as described above, the stable state is maintained as much as possible, and conversely, when the elongation rate becomes an abnormal value, the stable state is promptly returned. Can be done.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a control device for implementing the present invention, and FIG. 2 shows an example of control divisions for changes in elongation rate. In FIG. 1, the strip 6 is fed into a skin pass rolling mill 3 by an inlet bridle 1 and delivered by an outlet bridle roll 2. During that time, the elongation is caused by the rolling by the skin-pass rolling mill 3, the tension between the exit bridle roll 1 and the skin-pass rolling mill 3, and the tension between the skin-pass rolling mill 3 and the exit bridle roll 2. . 7 and 8 are the entry side, respectively.
Electric motors for driving the exit bridle rolls 1, 2 are controlled via bridle roll controllers 13, 14 and speed controllers 17, 18, respectively. Similarly, 9 is an electric motor for driving the temper rolling mill 3, which is controlled via a temper rolling mill control device 15 and a speed controller 19. 28 is a speed setting device that outputs set speeds to these control systems.

Tension detectors 4 and 5 are installed at the entrance and exit sides of the temper rolling mill 3, respectively, and detect the tension generated in the strip 6. Further, reference numerals 11 and 12 are pulse generators that detect the rotational speeds of the bridle rolls 1 and 2 on the entry and exit sides. The outputs of the pulse generators 11 and 12 are taken into an elongation factor calculator 21, and the elongation factor of the strip 6 is calculated. The elongation rate controller 22 is a controller for proportional and integral control elements, and is responsive to a deviation signal Δε obtained by subtracting the measured elongation rate ε10 of the strip by the elongation rate calculator 21 from the elongation rate set value ε11 by the elongation rate setting device 33. and outputs a control signal ΔP11.

[0012] When the elongation deviation Δε is within the set range,
The elongation rate controller 22 is connected to the signal P11 of the rolling load setter 34.
This load command value P1 is obtained by adding the control signal ΔP11 from
The rolling load P10 actually measured by the load cell 29 is subtracted from 2, and this value is set as a target value. The elongation rate is controlled by

When the elongation rate is out of the set range, the elongation rate is controlled by changing the speed of the bridle rolls 1 and 2. In this case, the elongation rate control ON/OFF logic circuit 23 according to the speed,
The elongation rate deviation Δε is the upper limit value Δε2 of the elongation rate deviation shown in FIG.
(or -Δε2), the elongation rate control is started, and then this control is stopped. The intermediate value Δε1 (or -
Δε1 ), the speed control output ΔV11 is output to the control gain calculation circuits 24 and 25 based on the control signal ΔP11 of the expansion rate controller 22. The control gain calculation circuits 24 and 25 calculate the control gain of the output ΔV11 in order to determine the speed correction values ΔV12 and ΔV13 of the inlet and outlet bridle rolls 1 and 2, respectively.

The inlet tension controller 26 is composed of proportional and integral control elements, and inputs an output signal obtained by subtracting the output T10 of the inlet tension detector 4 from the output T11 of the inlet tension setting device 31, and generates a tension control signal. It is output to the speed controller 17 of the entry side bridle roll 1. On the outlet side, the outlet tension controller 27 and the outlet tension setter 32 have the same functions as on the input side. Furthermore, although the above description has been made regarding the case where the skin pass rolling mill 3 is used as the speed master, the present invention is not limited to this, and even if the entry side bridle roll 1 and the exit side bridle roll 2 are used as the speed master. Similarly controllable.

[0015] In this way, the bridle rolls 1 and 2
While the elongation rate is controlled by the speed of , the rolling load of the temper rolling mill 3 is maintained constant by locking the hydraulic pressure to the rolling-up hydraulic cylinder 36 by a control valve (not illustrated) in the hydraulic circuit. The above explanation was based on the case where there is one skin-pass rolling mill and the entry and exit bridle rolls are driven individually, but even if there are multiple skin-pass rolling mills, side,
This can be implemented even when the exit bridle rolls are mechanically connected by a planetary gear mechanism.

When the present invention was applied to temper rolling of cold-rolled steel sheets, the length of the portion with poor elongation could be halved compared to when conventional elongation control was performed, and this effect was confirmed. Ta.

[0017]

Effects of the Invention When the elongation rate control method for a temper rolling mill according to the present invention is applied, the elongation rate is controlled by tension only when the elongation rate is out of the set range, so the elongation rate can be expanded without damaging the surface quality or shape. It becomes possible to quickly return the rate to the set range,
This is especially advantageous when the elongation rate fluctuates rapidly, such as during acceleration/deceleration or when passing through a welding point, and the length of the portion with poor elongation can be made as short as possible.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of a control device for implementing the present invention.

FIG. 2 is an explanatory diagram showing an example of control divisions for changes in elongation rate.

[Explanation of symbols]

1 Entry side bridle roll 2　Outside bridle roll 3 Temper rolling mill 4 Inlet tension detector 5 Output tension detector 6 Strip 7 Bridle roll drive motor 8 Bridle roll drive motor 9 Temper rolling mill drive motor 10 Hydraulic pressure reduction servo amplifier 11 Pulse generator 12 Pulse generator 13 Bridle roll control device 14 Bridle roll control device 15 Temper rolling mill control device 16 Temper rolling mill reduction control device 17 Bridle roll speed controller 18 Bridle roll speed controller 19 Temper rolling mill speed controller 21 Stretch rate calculator 22 Stretch rate controller 23 Elongation rate control on/off logic circuit 24 Control gain calculation circuit 25 Control gain calculation circuit 26 Inlet tension controller 27 Outlet tension controller 28 Speed setting device 29 Load cell 31 Inlet tension setting device 32 Output tension setting device 33 Elongation rate setting device 34 Rolling load setting device 36 Hydraulic cylinder for lifting

Claims (1)

[Claims] [Claim 1] A method for controlling the elongation rate of a temper rolling mill having bridle rolls disposed on the entry side and the exit side, wherein the tension is kept constant when the elongation rate after rolling is within a set range. The elongation rate is controlled by the rolling load of the temper rolling mill, and when the elongation rate is out of the set range, the rolling load of the temper rolling mill is kept constant and the speed of the bridle roll is changed to elongate. A method for controlling the elongation rate of a temper rolling mill, characterized by controlling the elongation rate.