JP2000326055A - Slab loop control method, slab loop control device, and recording medium - Google Patents

Abstract

(57) [Problem] To accurately and stably control the loop amount under a drum of a strip-shaped slab sent from a twin drum for cooling. SOLUTION: This is a method for controlling a state of a slab loop under a twin drum 1 in a twin-drum type continuous casting facility, wherein a slack amount of the slab loop is detected by a non-contact type detecting means 20 for the slab. By detecting and controlling the amount of slack of the slab to a predetermined value according to the detection result, it is possible to prevent the slab from breaking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loop control method, a control device and a recording medium for a slab obtained from a continuous casting facility, and more particularly to a slack amount of a slab sent from a twin drum of a twin-drum continuous casting facility. The present invention relates to an improvement in an apparatus and a method for detecting and appropriately controlling the detection.

[0002]

2. Description of the Related Art Twin-drum continuous casting (STC continuous casting)
In FIG. 5, as shown in FIG. 5, a pair of cooling drums 1 arranged in parallel with each other at a predetermined interval, and a pair of side surfaces arranged in a state pressed against both end surfaces of these cooling drums 1 The weir 52 constitutes a continuous casting mold.

[0003] A molten metal 54 stored in a preheating layer called a tundish 53 is continuously injected to form a pool 55 in the continuous casting mold. The contacting metal melt 54 is solidified thinly on the surface of the cooling drum 1.

[0004] By rotating the pair of cooling drums 1 whose surfaces are solidified with metal as shown by arrows, a strip-shaped slab 56 is formed of the thinly solidified metal and sent downward. A predetermined amount of molten metal 54 is always supplied to the tundish 53 from a molten steel pot 57 called a ladle while the supply amount is adjusted by a hydraulic cylinder 58.

[0005] The strip-shaped cast piece 56 immediately after being sent out from the cooling drum 1 is cooled and solidified to such an extent that the strip-shaped cast piece is maintained, but the temperature is still high and there is a possibility that the cast strip 56 will be broken if an excessive external force is applied. is there. Therefore, the cooling drum 1
The strip-shaped slab 56 is set to a free tension immediately below the slab, and the slab-shaped slab 56 is further horizontally pulled by a pinch roll 59 downstream to carry the slab. With such a configuration, a loop (slack) 60 is generated in the vicinity of the curve of the strip slab 56 according to the rotation speed of the pinch roll 59.

[0006]

In order to stably feed the strip-shaped slab 56 formed by the pair of cooling drums 1 to downstream equipment, a loop 60 of the slab formed below the cooling drum 1 is required. It is necessary to keep the size constant. Therefore, in the twin-drum continuous casting facility, a loop state detecting device called a looper 61 detects a loop amount (slack amount) of a slab under the cooling drum 1 and pinch rolls so that the loop amount becomes constant. 59 speed is controlled.

However, the conventional loop state detecting device called the looper 61 mechanically contacts the strip 56 under the cooling drum 1 to detect the loop amount. For this reason, the looper may not be able to follow the behavior of the strip-shaped slab 56, and the slab loop amount may not be accurately measured. Further, the looper 61 applying unnecessary external force to the strip-shaped slab 56 may cause slab rupture.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to make it possible to accurately and stably control a loop amount of a belt-shaped slab fed from a cooling twin drum under a drum.

[0009]

A method of controlling a slab loop according to the present invention is a method of controlling a state of a slab loop below a twin drum in a twin-drum continuous casting facility, wherein the slack of the slab loop is controlled. The amount is detected by a non-contact type slack detecting means, and the feed speed of the slab is controlled according to the result of the detection.

In one embodiment of the method of controlling a slab loop according to the present invention, the detection of the slack amount is performed by using a displacement meter using optical means including image processing, a displacement meter using ultrasonic waves, or a radio wave. This is performed using a displacement meter.

In one embodiment of the method for controlling a slab loop according to the present invention, the casting loop located downstream of the position of the slab loop with respect to the advancing direction of the slab based on the detection result of the slack amount. The feed speed of the slab in the one-sided conveying device is varied.

A slab loop control device according to the present invention is a device for controlling a state of a slab loop below a twin drum in a twin-drum type continuous casting facility, and is a slab transport disposed downstream of the twin drum. Means, a slack amount detecting means disposed between the twin drum and the slab conveying means, for detecting the slack amount of the slab loop in a non-contact manner with the slab, and a detection result of the slack amount detecting means. Speed changing means for changing the feed speed of the slab by the slab conveying means based on the

In one embodiment of the apparatus for controlling a slab loop according to the present invention, the slack amount detecting means uses a displacement meter using optical means including image processing, a displacement meter using ultrasonic waves, or a radio wave. Consists of a displacement gauge.

The recording medium of the present invention is a computer-readable recording medium in which a program for causing a computer to execute the above-described procedure of the slab loop control method is recorded.

A recording medium according to the present invention is a computer-readable recording medium which records a program for causing a computer to execute the procedure as each means of the slab loop control device.

[0016]

According to the present invention constructed as described above, since the slack amount of the slab is detected by the detecting means which is not in contact with the slab, it is possible to prevent an excessive external force from being applied to the slab. Can be. Further, since the non-contact detection means does not have a mechanical mechanism like the conventional looper 61, it is possible to suppress poor follow-up to the cast slab due to inertia or the like of the mechanical structure.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus and a method for controlling a slab loop under a twin drum in a twin drum type continuous casting facility according to an embodiment of the present invention will be described below with reference to the drawings.

First, the configuration of an apparatus for controlling the state of a slab loop will be described with reference to FIG. FIG. 1 is a schematic diagram showing a control device that varies the feed speed of the strip slab 2 based on the result of detecting the slab loop amount by the detection device 20. The configuration itself of the twin-drum continuous casting facility is the same as that described in FIG.

In FIG. 1, a cooling drum 1 cools a pool 55 of a molten metal 54 as shown in FIG.
It is sent out downward as a strip slab 2. Reference numeral 5 denotes a drive device capable of performing variable speed control. In this embodiment, an AC motor serves to rotate the cooling drum 1 in a direction indicated by an arrow. 7 is a speed control unit (Automatic Speed Regula
The rotation speed of the cooling drum 1 is controlled by making the speed of the AC motor 5 variable. By controlling the rotation speed of the cooling drum 1, the cooling speed of the molten metal 54 is controlled.

The pinch roll 3 provided downstream of the loop position of the strip 2 under the cooling drum 1 is
It plays a role of sending out the belt-shaped cast piece 2 bent at the loop position in the horizontal direction. Reference numeral 6 denotes a drive device capable of performing variable speed control. In this embodiment, an AC motor serves to rotate the pinch roll 3 in the direction of the arrow. Reference numeral 8 denotes a speed control unit (ASR) which controls the rotation speed of the pinch roll 3 by varying the speed of the AC motor 6.

In the twin-drum continuous casting equipment, the thickness of the strip 2 is determined by controlling the rotation speed of the cooling drum 1 and the gap between the drums.
Is the master speed of the line. On the other hand, the slab loop amount under the cooling drum 1 is determined because the rotation speed of the cooling drum 1 is the master speed.
Is the rotation speed of the pinch roll 3 disposed behind the line. That is, if the speed of the pinch roll 3 is higher than the master speed of the cooling drum 1, the loop amount of the slab under the drum decreases (the loop rises). The volume increases (the loop goes down).

In the present embodiment, a detecting device 20 is installed near a slab loop formed between the cooling drum 1 and the pinch roll 3, and the detecting device 20 and the like make the strip-shaped slab 2 non- The speed of the pinch roll 3 is controlled so that the loop amount is constant according to the cast slab loop amount detected by the contact.

FIG. 2 is an enlarged schematic view showing the positional relationship between the detecting device 20 and the strip-shaped slab 2 in the slab loop.
As shown in FIG. 2, in the twin-drum continuous casting facility according to the present embodiment, the detection of the slab loop amount below the twin-drum is performed by detecting a hanging state (slack state) of the strip-shaped slab 2 from the back surface. Then, the state of the slab loop is recognized. Specifically, the hanging state of the strip slab 2 can be recognized by measuring the distance between the detection device 20 and the strip slab 2 in the slab loop.

As the detection device 20, for example, a displacement meter using optical means represented by image processing or a laser beam, a displacement meter using ultrasonic waves, or a displacement meter using radio waves can be used. For example, when using a displacement meter using optical means using a laser beam or the like, a beam such as a laser beam is applied to the strip-shaped slab 2 in the slab loop to detect reflected light. Similarly, when a displacement meter using ultrasonic waves or radio waves is used, the strip-shaped slab 2 is irradiated with ultrasonic waves or radio waves to detect reflected waves. By detecting the time from when these laser beams, ultrasonic waves, etc. are emitted until the reflections return, and calculated by the slack amount detection arithmetic unit 4, from the detecting device 20 to the strip-shaped slab 2 in the slab loop. Can be measured. Further, the distance may be obtained by detecting the position of the reflected wave in the same manner as in a normal distance measuring device using infrared light.

The slack detection calculating device 4 shown in FIG.
The loop amount (slack amount) of the strip-shaped slab 2 is calculated from the distance data between the strip-shaped slab 2 and the detection device 20 detected by 0. Therefore, the detecting device 20 and the slack detection calculating device 4 constitute a slack amount detecting means. Specifically, as described above, when measuring the distance from the detection device 20 to the strip 2 based on the time until the reflected wave returns, an operation of converting the time to the distance is performed, and the distance data is further calculated. Calculate the slack amount from The calculation from the distance data to the slack amount is such that the loop amount is large when the distance data from the detection device 20 to the strip 2 is small, and the loop amount is small when the distance data is large. This is the calculation to be adjusted. Then, the calculation result is transmitted to a PI (Proportional and Integral) control unit 1 in the master control device 9.
Sent to 2.

The master control device 9 is a casting speed master 1
0, a plate thickness correcting means 11 and a PI control unit 12. The master rotation speed of the cooling drum 1 is set in the casting speed master 10. In the twin-drum continuous casting equipment as shown in the present embodiment, control is performed so that the thickness of the outlet side of the cooling drum 1 is constant, and the thickness depends on the rotation speed of the cooling drum 1. Since the cooling speed is determined by the cooling speed, the speed of the cooling drum 1 becomes the master speed of the line. Therefore, the cooling drum 1 defined in advance
Based on the mutual distance, the speed of the cooling drum 1 for obtaining a desired plate thickness is set in the casting speed master 10.

When the rotational speed of the cooling drum 1 per unit time is set to be large in setting the rotational speed in the casting speed master 10, the strip-shaped slab 2 at the drum exit side is formed to be thin. When the number of rotations per unit time of the cooling drum 1 is set to be small, the strip-shaped slab 2 on the drum exit side is formed to be thick.

The rotation speed of the cooling drum 1 set by the casting speed master 10 is corrected by the thickness correcting means 11 as necessary. That is, the cooling drum 1 is provided with a reaction force meter (not shown) for detecting a reaction force that fluctuates in accordance with the sheet thickness. Input as correction data. The rotation speed of the cooling drum 1 is corrected when the reaction force of the strip 2 against the cooling drum 1 input from a reaction force meter (not shown) is different from a desired value.

The master controller 9 combines the rotation speed of the cooling drum 1 set by the slab speed master 10 and the thickness correcting means 11 with the slack amount information of the strip slab 2 obtained from the slack detection arithmetic unit 4. By sending the signal to the speed control unit 8, the rotation speed of the AC motor 6 is controlled by the speed control unit 8. Thereby, the rotation speed of the pinch roll 3 with respect to the rotation speed of the cooling drum 1 can be controlled, and the slack amount of the strip-shaped slab 2 in the slab loop can be controlled to be constant.

Next, a method of controlling the slack amount of the slab loop using the slab loop control device shown in FIG. 1 will be described. FIG. 3 is a flowchart illustrating a processing procedure of a method of controlling a slab loop in the twin-drum continuous casting facility of the present invention.

The number of rotations of the cooling drum 1 per unit time is set in the casting speed master 10 in accordance with the thickness of the strip 2 to be rolled. When the information on the rotation speed of the cooling drum 1 is corrected by the thickness correction means 11, the information is corrected according to the thickness correction data.
Is transmitted to the speed control unit 7 for controlling the rotation of the motor. The speed control unit 7 drives the AC motor 5 according to the given speed information to rotate the cooling drum 1.

The rotation of the cooling drum 1 causes the pool 5
The molten metal 54 in 5 is cooled and sent out downward as a strip-shaped slab 2. In FIG. 1, a strip-shaped slab 2 sent out from a cooling drum 1 is sent out by a pinch roll 3 passing in front of a detection device 20. Then, the distance between the detection device 20 and the strip-shaped slab 2 is detected by the detection device 20 provided corresponding to the position of the slab loop.

In the first step S41 shown in FIG. 3, the distance between the detecting device 20 which fluctuates according to the amount of slack of the strip 2 located below the cooling drum 1 and the strip 2 is determined. To detect.

The distance data from the detection device 20 is calculated by the slack detection calculation device 4 in step 42,
A looseness detection signal is generated. This detection signal is sent to the master control device 9 and sent to the speed control unit 8 via the PI control unit 12 together with the signal of the rotation speed of the cooling drum 1 from the casting speed master 10 and the thickness correction means 11.

Next, proceeding to step S43, the speed controller 8 determines whether or not the slack amount in the slab loop exceeds a predetermined value based on the result of the calculated slack amount detection signal. If the slack amount exceeds the predetermined value, the process proceeds to step S44, where the speed control unit 8 rotates the pinch roll 3 with respect to the rotation speed of the cooling drum 1 set by the casting speed master 10 and the thickness correction unit 11. Increase speed. Specifically, when the slack amount of the slab loop is large and the distance between the strip-shaped slab 2 and the detection device 20 is short, the rotation speed of the pinch roll 3 is increased. On the other hand, if the amount of slack does not exceed the predetermined value in step S43, that is, if the amount of slack in the slab loop is small and the distance between the strip-shaped slab 2 and the detection device 20 is large, step S43 is performed. Proceeding to 45, the rotation speed of the pinch roll 3 is reduced.

It should be noted that the predetermined value in step S43 may have a predetermined range of width, and when the width exceeds this range, the speed of the pinch roll 3 may be changed. In this case, when the loop amount exceeds the width, the speed of the pinch roll 3 is increased, and when the loop amount decreases beyond the width, the speed of the pinch roll 3 is decreased.
Then, when the slack amount is within the range, the strip-shaped slab 2 is fed at the current speed without changing the speed of the pinch roll 3.

In the above-described steps, the detection of the distance by the detection device 20 may be performed at all times, or may be performed at predetermined time intervals.

FIG. 4 is a characteristic diagram showing a state where the slab loop is controlled by the slab loop control method according to the present embodiment. As shown in FIG. 4, according to the method of controlling the slab loop in the present embodiment, the loop amount of the strip-shaped slab 2 is obtained based on the distance information detected by the detection means 20, and the loop amount is determined according to the loop amount. Since the feed speed of the strip-shaped slab 2 by the pinch roll 3 is varied, the variation of the loop amount of the slab loop can be suppressed within a minute range d shown by a dotted line in FIG.

As described above, according to the present embodiment, the non-contact type detecting device 2 in which the slack amount of the strip-shaped slab 2 in the slab loop is arranged at an appropriate position with respect to the strip-shaped slab 2 is provided.
0, and the rotation speed of the pinch roll 3 is made variable based on the detection result to control the slack amount of the cast slab loop. The measurement can be performed accurately without applying any external force to the slab 2, and the loop control using the pinch roll 3 can be performed with high accuracy and stability. That is, by using the non-contact type detection device 20, unlike a conventional contact type detection device such as a looper, it is possible to avoid breaking of the cast slab under the cooling drum 1. In addition, since the non-contact type slack detection device does not have a mechanical mechanism, there is no poor follow-up to the slab due to inertia or mechanical deterioration of the mechanical structure, and the slack amount can be accurately measured. Further, there is also an advantage that the operation of the slackness detection arithmetic unit 4 is excellent in flexibility such as removing a component of high frequency fluctuation of the cast slab.

In the above-described embodiment, an example is shown in which the loop state is detected by the detecting means 20 from the back surface of the strip-shaped slab 2, so that the slack amount of the strip-shaped slab 2 is reliably detected. be able to. However, strip slab 2
Is not necessarily detected from the back, and may be detected, for example, diagonally backward or from the side. Further, as the detection device 20, a device that captures an image of the slab 2 in the slab loop and detects the distance from the slab 2 by image processing may be used.

In the above embodiment, the slack amount is converted from the distance between the detecting device 20 and the strip slab 2, and the speed of the pinch roll 3 is controlled based on the slack amount. The speed may be controlled by adjusting the speed. Alternatively, the speed control may be performed by directly using the distance data or the time data measured by the detection device 20.

(Other Embodiments of the Present Invention) The present invention is directed to an apparatus connected to the various devices or a computer in a system so as to operate various devices so as to realize the functions of the above-described embodiments. The scope of the present invention also includes a case where the present invention is implemented by supplying a program code of software for realizing the functions of the above-described embodiment and operating the above-described various devices according to a program stored in a computer of the system or the apparatus. It is.

In this case, the program code itself of the software realizes the functions of the above-described embodiment, and the program code itself and means for supplying the program code to the computer,
For example, a storage medium storing such a program code constitutes the present invention. As a storage medium for storing such a program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM,
A magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the supplied program code, not only the functions of the above-described embodiment are realized, but also the OS (operating system) or other operating system running on the computer. Needless to say, even when the functions of the above-described embodiments are realized in cooperation with application software or the like, such program codes are included in the embodiments of the present invention.

Further, after the supplied program code is stored in a memory provided in a function expansion board of the computer or a function expansion unit connected to the computer, the function expansion board or the function expansion unit is specified based on the instruction of the program code. It is needless to say that the present invention also includes a case where the CPU or the like provided in the first embodiment performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0046]

According to the present invention, it is possible to accurately measure the slack amount of a slab without applying any external force to the slab under the twin drum. Therefore, it is possible to reliably and stably feed the slab, avoiding inconveniences such as the slab breaking or the detection means being unable to follow the behavior of the slab, and to improve the reliability of the slab manufacturing process. It can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a control device for a slab loop according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a slab loop detection device according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a method for controlling a slab loop according to an embodiment of the present invention.

FIG. 4 is a characteristic diagram illustrating a state in which a slab loop is controlled by a slab loop control device according to an embodiment of the present invention.

FIG. 5 is a schematic diagram showing a partial configuration of a twin-drum continuous casting facility according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cooling drum 2 Strip cast piece 3 Pinch roll 4 Looseness detection arithmetic unit 5, 6 AC motor 7, 8 Speed control unit 9 Main control unit 10 Casting speed master 11 Sheet thickness correction means 12 PI control unit 20 Non-contact type detection device

Claims (7)

[Claims] 1. A method for controlling a state of a slab loop under a twin drum in a twin-drum continuous casting facility, wherein a slack amount of the slab loop is detected by a non-contact slack detecting means, and the detection is performed. A method for controlling a slab loop, comprising controlling a slab feed speed in accordance with the result of (1). 2. The displacement meter according to claim 1, wherein the detection of the slack amount is performed by a displacement meter using optical means including image processing, a displacement meter using ultrasonic waves, or a displacement meter using radio waves. Control method of slab loop. 3. A feed speed of the slab in a slab transport device downstream of a position of the slab loop with respect to a traveling direction of the slab based on a detection result of the slack amount. The method for controlling a slab loop according to claim 1 or 2, wherein: 4. A device for controlling a state of a slab loop under a twin drum in a twin-drum continuous casting facility, comprising: a slab conveying means disposed downstream of the twin drum; A slack amount detecting unit disposed between the slab loop and the slack amount of the slab loop, the slack amount detecting unit detecting the slack amount of the slab loop in a non-contact manner with the slab, And a speed varying means for varying a feed speed of the slab by means of a slab loop. 5. A displacement meter using optical means including image processing, a displacement meter using ultrasonic waves, or a displacement meter using radio waves, wherein said slack amount detecting means is provided.
2. The control device for a slab loop according to claim 1. 6. A computer-readable recording medium in which a program for causing a computer to execute the procedure of the method for controlling a slab loop according to claim 1 is recorded. 7. A computer-readable recording medium in which a program for causing a computer to function as each unit of the slab loop control device according to claim 4 or 5 is recorded.