JPH10328721A - Speed control method of rolling mill when stripping steel plate - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To control the rotation drive motor of a rolling mill roll at the time of stripping of a steel sheet in hot reversible rolling of a thick plate, etc., by using a relatively simple configuration, the rotation drive motor at the time of stripping of the strip of steel. The production speed will be improved by reducing the time outside the mill. In A rolling mill rotation drive motor 4 of the rolling mill rolls are speed control based on the speed reference value V _S, detects Shirinuke of the rolled material by the load meter 6 installed in the rolling mill, When this is compared with the actual speed V and the speed reference value V _S of the rolled material during Shirinuke, actual speed V becomes lower than the reference speed V _S at such heavy load rolling, at the moment of the Shirinuke a speed command instead of the actual speed V to the speed reference value V _S, then decelerates and reverse rotation drive motor 4 at a constant deceleration rate alpha, by suppressing the speed increasing during Shirinuke, Shirinuke The time from reversal to reversal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the speed of a roll rotation drive motor in a reversible rolling mill, and more particularly, to preventing the speed of a rotation drive motor from jumping when a steel plate bottom comes off in a hot reversible rolling mill for thick plates. And a speed control method for controlling the speed.

[0002]

2. Description of the Related Art For example, in hot rolling of a thick plate, as shown in FIG. 4 (a), a quadruple reversible rolling mill comprising a pair of upper and lower work rolls WR and a backup roll BR is used, and a heating furnace is used. After the heated material to be rolled is rolled in the forward direction, the roll gap is immediately narrowed and rolled in the reverse direction, and this is repeated a plurality of times to obtain a steel plate having a predetermined thickness. In such a quadruple reversible rolling mill, a pair of upper and lower work rolls WR are driven to rotate by a rotary drive motor 4, and the speed of the rotary drive motor 4 is controlled by a speed reference generator 1, a speed controller 2, and a motor drive 3. Control.

[0003] speed reference generator 1 outputs a speed reference value V _S as shown in FIG. 4 (b) to the speed control unit 2, in the speed control device 2, and the speed reference value V _S, the rotary drive The motor 4 is compared with the actual speed value V from the speed detector 5 and the deviation is output to the motor driving device 3. The motor driving device 3 controls the motor current of the rotary driving motor 4 so that the deviation disappears. ing. Further, when the tail end of the material to be rolled comes off from the rolling mill, in order to prevent an increase in the speed of the rotary drive motor 4 due to the absence of the load,
The load meter 6 load change in which is provided to the pressing device of the rolling mill to detect a Shirinuke, lowering the speed reference value V _S at a constant deceleration rate α by Shirinuke detection signal from Shirinuke detecting device 7, the rotary drive motor 4 to prevent the speed increase, and decelerate the rotation drive motor 4.
By reversing the time, the time outside the mill (time other than rolling) of the steel sheet is reduced.

[0004]

However, in the above-described conventional speed control method, since the speed is controlled based on the speed reference value V _S , as shown in FIG. During heavy load rolling in rolling, the speed of the rotary drive motor 4 cannot be increased (because rolling torque> motor generated torque (rolling torque + motor rotation torque)), for example, 100
% When the actual speed value V is 70% with respect to the speed reference value V _S , and when the steel sheet falls out of the rolling mill in this state, the speed reference value V _S is higher than the actual speed value V. instantaneous velocity actual value V is trying to follow the speed reference value V _S (which tries to increase the speed actual value V to 100% from 70%). As a result, a large speed-up portion is formed in the actual speed value V after the trailing edge, and the increase in the speed of the rotary drive motor 4 increases the time from the trailing edge to the reverse rotation. However, there is a problem that it becomes long.

[0005] Regarding the speed control method of the rolling mill,
Japanese Patent Application Laid-Open No. 63-72415 proposes a speed control method for preventing a trouble caused by an instantaneous speed increase when a material to be rolled passes through a tail end in a wire rod rolling mill. In this speed control method, the tail end of the wire is detected by a tail end detector installed upstream of the finishing mill for the wire, and the tail end of the wire is tracked. When the wire reaches a predetermined position in the finishing mill, a speed change (deceleration) is applied to the drive motor of the rolling mill to offset the speed increase of the wire rod, thereby decreasing the speed of the wire rod tail end and causing trouble caused by an instantaneous loop. After that, the tail end is detected by the tail end detector installed downstream of the finishing mill, and the speed of the drive motor is returned to the original speed.

However, this speed control method is a speed control in the rolling of a wire rod, and cannot be applied to a reversible rolling of a thick plate in which rolling is performed in forward and reverse directions. In addition, since this speed control method uses a detector outside the rolling mill,
There are many malfunctions of the tail end detector due to external factors such as water and water vapor, the tail end tracking accuracy is poor, and the speed of the drive motor during rolling is reduced. There is also a problem of increasing the speed increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a relatively simple configuration to reliably increase the speed of a rotary drive motor of a rolling mill roll when a steel plate is pulled out. It is an object of the present invention to provide a method for controlling the speed of a rolling mill at the time of steel plate bottom removal, which can reduce the time outside the mill and improve the production efficiency.

[0008]

To achieve the above object, according to an aspect of, the present invention, as shown in FIG. 1, a rolling mill rotation drive motor 4 of the rolling mill rolls are speed control based on the speed reference value V _S in, the load meter 6 installed in the rolling mill to detect a Shirinuke of the rolled material, compares the actual speed V and the speed reference value V _S of the rolled material at the time of Shirinuke, the deviation ( = | V _S | − | V |, | V _S |> | V |) exceeds a predetermined value, the actual speed value V is used as a speed command instead of the speed reference value V _S at the moment of the above-mentioned loss of hips. The rotational drive motor 4 is decelerated and reversed at a constant acceleration / deceleration rate α.

In the above configuration, a roll load (load) is detected by a load meter installed in a rolling mill,
When the detected load becomes equal to or less than a preset value, it is detected as a bottom loss of the steel plate. Since the load cell is used, the bottom of the steel plate can be reliably detected without being affected by the environment such as water or water vapor. The speed reference value V _S at the time of detection of the trailing edge loss is compared with the actual speed value V. For example, if the actual speed value V drops significantly from the speed reference value V _S during heavy load rolling, the speed reference value V _S becomes the actual speed value. Is replaced by the value V. Only at the moment of the detection of the missing part, the lower speed actual value V becomes a speed command. From this actual speed value V, deceleration at a constant acceleration / deceleration rate α is started, and the rotation is reversed. Therefore,
Since the speed command at the time of missing the hips is lower than before, the speed-up portion of the actual speed V is significantly smaller than before,
The time from assault to reverse is greatly reduced as compared with the conventional case. (See FIG. 2).

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. This is an example applied to hot rolling of a thick plate by a quadruple reversible rolling mill. FIG. 1 is a block diagram of a control device for implementing the speed control method of the present invention, and shows a graph of a time change of a speed reference value and a speed actual value in the control device. 2 and 3 show graphs comparing speed control between the present invention and the conventional one.

In FIG. 1 (a), a pair of upper and lower work rolls WR of a quadruple reversible rolling mill are driven to rotate by a rotary drive motor 4 as in the prior art. Controlled. A speed detector 3 is coaxially mounted on the rotary drive motor 4 and detects the actual speed value V of the rotary drive motor 4. A load cell (load cell) 6 for detecting the roll load is installed in the rolling device of the rolling mill, and the detected load value of the load cell 6 is output to the trailing edge detection device 7. The back loss detection device 7 compares the load detection value from the load meter 6 with a preset load set value. If the load detection value is smaller than the load set value, it is determined that the back loss has occurred and the back loss signal is output. Is output.

In such a configuration, in the present invention, the speed control device is changed to the speed reference replacement device 2 by changing a processing program in the conventional speed control device. In the speed reference replacement device 2, the speed reference value V _S output from the speed reference generation device 1 and the speed reference value from the speed detector 5 are output at the timing when the bottom loss detection signal is output from the bottom loss detection device 7. The actual value V is compared with the deviation (| V _S |
- | V |> 0) exceeds a predetermined value, replacing the reference speed V _S of the speed actual value V. The predetermined value is set such that the substitutions are made when the actual speed V relative to the speed reference value V _S by heavy load rolling is greatly reduced. It is also possible to set such that the substitutions are made even if the speed reference value V relative to the speed reference value V _S is decreased smaller. After this replacement, the speed reference value V _S at a constant acceleration / deceleration rate α is set as in the conventional case.

Only at the moment when the bottom missing detection signal is input to the speed reference replacement device 2, the actual speed value V lower than the speed reference value V _S is used as a speed command, and thereafter, the speed actual value V is replaced by a constant value. The rotational drive motor 4 is decelerated at the acceleration / deceleration rate α, and then reversely rotated. As shown in FIG. 2 and FIG. 3, in the case of the present invention, the speed command at the time
Since by 0% of the reference speed V _S is replaced by for example, 70% of the actual speed V, it is possible to considerably smaller than the speed increasing peak velocity actual value V during Shirinuke to conventional butt It is possible to reduce the time from the slippage to the reverse rotation, and it is possible to immediately shift to the next rolling. For example, as shown in FIG.
Seconds can be shortened, and time outside the mill can be shortened to improve production efficiency.

Although the above description has been given of hot rolling of a thick plate, the present invention is not limited to this, and the present invention can be applied to other reversible rolling.

[0015]

As described above, according to the present invention, the run-out of the material to be rolled is detected by the load meter installed in the rolling mill, and the actual speed value and the speed reference value of the material to be rolled at the time of the break-through are detected. When the deviation exceeds a predetermined value, the actual speed value is replaced with the speed reference value at the moment of the loss of the hips, and the speed command is used as the speed command.Then, the rotational drive motor is decelerated and reversed at a constant acceleration / deceleration rate. Therefore, the following effects can be obtained.

(1) It is possible to suppress an increase in the speed of the rotary drive motor of the rolling mill roll that occurs when the steel plate comes out of the tail, and to shorten the time outside the mill, thereby improving the production efficiency.

(2) Since the load cell installed in the rolling mill is used as the tail end detector, the tail end can be reliably detected without being influenced by the environment. Since the speed reference value is replaced with the actual speed value, the speed increase of the rotary drive motor can be reliably suppressed. Further, since it is only necessary to replace the speed reference value with the actual speed value, the object can be achieved by a relatively simple and inexpensive device.

[Brief description of the drawings]

FIG. 1 (a) is a block diagram of a control device for implementing a speed control method of the present invention, and FIG. 1 (b) is a graph showing a time change of a speed reference value and a speed actual value in the control device.

FIG. 2 is a graph comparing the time change of a speed reference value and a speed actual value of a rotary drive motor with the present invention and a conventional one.

FIG. 3 is a graph comparing the actual speed value of a rotary drive motor and the change over time in torque current between the present invention and a conventional motor.

FIG. 4A is a block diagram of a control device for implementing a conventional speed control method, and FIG. 4B is a graph showing a time change of a speed reference value in the control device.

[Description of Signs] 1 ... Speed Reference Generator 2 ... Speed Reference Replacement Device (Speed Control Device) 3 ... Motor Drive Device 4 ... Rotary Drive Motor 5 ... Speed Detector 6 ... Load Gauge 7 ... Assault Detection Device

Claims (1)

[Claims] In a rolling mill in which a rotation drive motor of a rolling mill roll is speed-controlled based on a speed reference value V _S , a trailing edge of a material to be rolled is detected by a load meter installed in the rolling mill. comparing the actual speed V and the speed reference value V _S of the rolled material during Shirinuke, when the deviation exceeds a predetermined value, instead of the actual speed V to the speed reference value V _S at the moment of the Shirinuke A speed control method for a rolling mill at the time of steel plate bottom removal, wherein a speed command is set as a speed command, and thereafter, the rotation drive motor is decelerated and reversed at a constant acceleration / deceleration rate α.