JP2632893B2 - Apparatus and method for controlling transfer of slab under significant pressure reduction of hot slab - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a slab conveyance control device and a conveyance control method under a large pressure of a hot slab.

[Prior art] In a width reduction device of a type in which the width is reduced by moving a hot slab between dies that are opened and closed periodically, one width reduction is completed, and the dies are opened and the slab is opened. It is necessary to move the slab to the position where the next width reduction is performed while not in contact. In this case, high-speed and accurate conveyance of the slab is important for improving the rolling efficiency and the width accuracy.

For this reason, a method has been proposed in which pinch rolls capable of firmly sandwiching a slab are arranged before and after a mold, and the pinch rolls are driven by electric motors capable of controlling the rotation speed of each (Japanese Patent Application No. 58-226907). JP-A-60-12
1001).

When performing slab conveyance in such a way, the front pinch roll performs slab conveyance alone until the slab reaches the rear pinch roll, and when the slab reaches the rear pinch roll, sandwiches the slab with the rear pinch roll, Transport is performed using both front and rear pinch rolls.

[Problems to be solved by the invention]

When the slab is conveyed by a single driving device, it is advantageous that the rotational speed controllability of the driving device is as high as possible in order to improve the rolling efficiency.However, when both pinch rolls are used together, the front and rear driving devices are independent. When rotation speed control is performed
A difference occurs in the roll peripheral speed of the front and rear pinch rolls due to differences in load torque and roll diameter. As a result, the surface of the slab may be scratched, or a horizontal force exceeding the design allowable value may be applied to the pinch roll.

An object of the present invention is to provide a slab conveyance control device and a conveyance control method which have improved such a drawback. The slab is simultaneously conveyed by the front and rear pinch rolls. Provided is a technique for performing high-efficiency width reduction without applying an unacceptable horizontal force in between and without flaws on the slab surface.

[Means for solving the problem]

The apparatus of the present invention is a method for controlling the transfer of a slab under a hot slab under a significant pressure, and a pair of dies that open and close periodically,
A hot slab width reduction having pinch rolls respectively disposed on the front and rear surfaces of the mold with respect to the traveling direction of the slab, and sequentially reducing the width of the slab by moving the slab intermittently between the dies. The device has the following features.

(1) Each of the pinch rolls is provided with a drive device capable of independently controlling the rotation speed and switching control characteristics for rotation speed fluctuation between two stages of high speed and gentle response.

(2) Means for confirming that the rear pinch roll has sandwiched the slab.

(3) A plant controller for judging the switching timing of each rotation control characteristic of the front and rear pinch roll driving devices and outputting a switching command.

The method of the present invention is characterized in that, in the process of reducing the width of one slab in the hot slab width reduction method, [I] the rotation of the front pinch roll driving device is performed while only the front pinch roll of the reduction device holds the slab. Set the speed control characteristic to high and set the rear pinch roll drive to a gradual characteristic with respect to the rotation speed fluctuation. (II) After confirming that the rear pinch roll pinched the slab, The rotation speed control characteristic is set to be high, and the front pinch roll driving device is set to have a gentle characteristic with respect to the rotation speed fluctuation.

A method for controlling the transfer of a slab under a significant pressure reduction of a hot slab.

[Action]

 FIG. 1 is a block diagram showing a specific configuration of the present invention.

On the front side of the pair of dies 1, a front pinch roll 2, a driving motor 3 for driving the pinch roll 2, and a speed detector 4 are provided. As means for controlling the speed and easing the speed control response,
It has a drive device 5 that can be turned on and off using a doop loop control by electric feedback.

As similar elements on the rear side of the mold 1, a rear pinch roll 6, a motor 7 for driving the same, and a speed detector 8 are provided. The speed can be controlled, and the dow loop control can be turned on and off by current feedback. It has a driving device 9. Further, the rear pinch roll 6 is provided with a pulse generator 12 for confirming slab sandwiching, and a slab detector 11 is provided immediately near the rear surface of the rear pinch roll 6.

These drive devices 5 and 9 are provided with a plant controller 10 capable of outputting a speed reference, a dow loop on / off command, and a pinch roll pinching command.

The plant controller 10 controls the front pinch roll to the maximum capacity when only the front pinch roll is holding the slab, and controls the rear pinch roll to the maximum capacity when both the front and rear pinch rolls hold the slab. At the same time, the front pinch roll has a gradual characteristic with respect to a change in speed, and a horizontal force generated on the pinch roll due to a difference in rotation speed between the pinch rolls is reduced.

〔Example〕

The slab extracted from the heating furnace and advancing in the direction of arrow 13 is sandwiched by the front pinch rolls 2 and starts to be reduced in width by the mold 1. The plant controller 10 outputs the same speed reference v * corresponding to the slab movement target amount to the front and rear pinch roll driving devices 5 and 9, and outputs a draw loop command to the rear pinch roll driving device 9.

When the slab detector 11 detects the slab, the plant controller 10 clamps the slab by the rear pinch roll, confirms the completion of the clamping by the pulse generator 12, and then aborts the droop command to the rear drive unit, and replaces the droop command to the front drive unit. Is output. According to this method, even when the roll peripheral speed corresponding to the speed reference is different between the front and rear pinch rolls, the pinch roll on which the dough loop control is added follows the roll peripheral speed of the other pinch roll.

In the present embodiment, as a means for slowing down the speed control response, the down loop control by the current feedback is adopted. However, another method (for example, switching to voltage control) may be adopted.

Also, the dough loop control may be performed on the plant controller side.

Further, it has been described that the slab detector 11 is installed on the exit side of the rear pinch roll 6.
A slab detector for detecting the rear end of the slab may be installed on the entry side of the slab, and the pinch roll for performing the drooping control based on this detection may be switched. In other words, the object of the present invention can be achieved if any one of the pinch rolls controls the speed control response slowly only while both the front and rear pinch rolls are simultaneously holding the slab. .

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the first half (slab conveyance with a front pinch roll) and the second half (slab conveyance with a rear pinch roll) of a slab without flawing a slab surface or applying an unacceptable horizontal force to a pinch roll. ) Can be continuously switched, so that efficient rolling work is possible.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing the configuration of the width reduction press and its drive control system. 1 ... Die 2,6 ... Pinch roll 3,7 ... Driving motor 4,8 ... Speed detector 5,9 ... Driving device 10 ... Controller 11 ... Slab detector 12 ... Pulse generator

Claims (2)

(57) [Claims] A slab is provided between a pair of molds which are periodically opened and closed, and pinch rolls respectively provided on a front surface and a rear surface of the mold in a traveling direction of the slab. In a hot slab width reduction device for sequentially reducing the width of a slab by sequentially moving the slab, the pinch rolls each have independently controllable rotational speeds, and have two-stage control characteristics of high-speed and gentle response to rotational speed fluctuation. And a means for confirming that the rear pinch roll has pinched the slab, and determine a switching timing of each rotation control characteristic of the front and rear pinch roll drive and issue a switch command. A slab conveyance control device under a large pressure of a hot slab characterized by having a controller for outputting. 2. In the process of reducing the width of one slab in the hot slab width reduction method, the rotational speed control characteristics of the front pinch roll driving device while only the front pinch roll of the reduction device holds the slab. After setting the rear pinch roll drive to moderate characteristics with respect to the rotation speed fluctuation, and confirming that the rear pinch roll has pinched the slab, increase the rotation speed control characteristics of the rear pinch roll drive. A method for controlling the transfer of a slab under a significant pressure of a hot slab, wherein the setting is performed and the front pinch roll drive device is set to have a gentle characteristic with respect to the rotation speed fluctuation.