JP2003053490A - Method and controller for controlling change of mold width in slab continuous casting facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a controller for controlling change of a mold width in a slab continuous casting facility which enable, even in the slab continuous casting facility performing fluid state adjustment of molten steel with impression of magnetic field, accurate measurement of inclination angles of short side walls of the mold during changing the width, and adjustment of the inclination angles by using the measurement information in real time. SOLUTION: In the method for controlling the change of the mold width in the slab continuous casting facility in which the moving quantity and the inclination angles in the short side walls of the mold are adjusted to change the mold width, the adjustment of the inclination angle in the short side walls of the mold is performed by using an optical fiber-loop type angle velocity sensor disposed at the short side walls.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold width change control method and control device for slab continuous casting equipment, and more specifically, to apply electromagnetic force to a mold having a rectangular cross section,
The present invention relates to a technique for smoothly and stably performing so-called "mold width change" in which a short side wall of a mold is moved along the long side wall during operation in a continuous casting machine capable of adjusting the flow state of the poured molten steel.

[0002]

2. Description of the Related Art Continuous casting of molten steel is generally performed as follows.

Molten steel that has been refined and melted into predetermined components in a refining vessel (eg, converter, electric furnace, etc.) is tapped into a ladle. Then, as shown in FIG. 3, the molten steel 2 held in the ladle 1
Is an intermediate container called a tundish 3 (a container for making molten steel uniform or rectifying the molten steel before it is poured into the mold) through a dipping nozzle provided at the bottom of the mold 4 whose outer wall is a cooling system. Is injected into. In the mold 4, since the molten steel in contact with the water-cooled outer wall forms a solidified shell, the solidified shell is continuously drawn out to the cooling zone (water spray etc.) 6 provided below by using the roller group 7, The molten steel is gradually cooled to obtain a long solidified body 5 which is completely solidified inside. Finally, the solidified body 5 is cut with a gas or the like into a predetermined length to form a steel slab such as a so-called slab or bloom, which is sent to a downstream rolling step and processed into a steel plate, a shaped steel material or the like. Then shipped to the customer.

By the way, in order to manufacture a steel slab (hereinafter referred to as a slab) having a flat rectangular cross-sectional shape by such continuous casting, two short side walls and a long side wall facing each other are used. The formed mold is used. The short side wall of the mold is movable by a drive device in a direction perpendicular to the surface of the mold so that the size of the slab can be quickly changed. Is set to be larger than the flat cross section of the lower part. This inclination takes into consideration that the solidified body contracts when the molten steel solidifies. If the inclination is not proper, normal heat generation of the solidified shell is hindered due to poor heat removal of the mold or excessive stress on the solidified shell, resulting in breakout (melting loss of the solidified shell or mold wall, This is because it causes a destruction phenomenon and causes the operation to stop.

Generally, as shown in FIG. 1, the drive unit (mold width changing unit) has two drive shafts 15 above and below the short side wall 13, and the two drive shafts 1 are provided.
By sequentially adjusting the positions of the upper end and the lower end of the short side wall 13 by pushing and pulling 5, the position of the short side wall 13 during the width change (the drive device is operating) is determined and the inclination is also controlled. is doing. At that time, the position and the inclination angle of the short side wall are indirectly measured by the displacement amount of the drive shaft 15. The drive shaft 15 is formed of a motor 16, a hydraulic cylinder, etc. For example, in the case of motor drive, the positional displacement of the drive shaft 15 is measured by a pulse generator 17 attached to the motor shaft. However, the driving device and the short side wall 13 are
Since it is mechanically connected via a reducer, gear, etc.,
Due to mechanical backlash, the measured value of the position and inclination angle of the short side wall indirectly measured from the displacement amount of the drive shaft and the actual value do not necessarily match. Of these, since the width of the cast slab has an allowable range, the position of the short side wall (particularly the position of the lower end) itself that determines the width of the mold does not pose a big problem.

However, the inclination angle of the short side wall 13 during the width change must be strictly adjusted in accordance with the shape of the slab, which changes in order, in order to avoid operational troubles such as breakout. It must be adjusted more properly even during normal casting without width change. For that purpose, it is necessary to correctly measure the actual inclination angle of the short side wall 13. However, the mold itself vibrates up and down called oscillation during normal casting, and since it is unitized so that it can be replaced in a relatively short time, the mounting space for the tilt angle measuring device is extremely small. Be constrained to. It should be noted that the conventionally used online inclination angle measuring instrument uses a torque motor called a servo balance type.

However, the recent continuous casting machine for slab production is
A magnetic field may be applied to the mold in order to adjust the flow state of the molten steel in the mold. In that case, the conventional tilt angle measuring instrument described above is often affected by the magnetic field and measurement becomes impossible. In addition, the conventional tilt angle measuring instrument considers the influence of mold vibration on the measured value, encloses highly viscous insulating oil etc. in the movable part, increases the time constant of the measurement system, and influences the vibration frequency. Hold down. Therefore, the real-time property of measurement is lacking, and the obtained measurement value cannot be used for the inclination adjustment of the short side wall, and it is used only for the inclination monitoring in the steady state (when the width is not changed). The current situation is not.

[0008]

In view of the above circumstances, the present invention provides an accurate inclination angle of the short side wall of the mold during width change even in a slab continuous casting facility for adjusting the flow state of molten steel by applying a magnetic field. It is an object of the present invention to provide a mold width change control method and a control device for a slab continuous casting equipment, which can not only measure the measurement angle but also use the measurement information in real time to adjust the inclination angle.

[0009]

Means for Solving the Problems The inventor has conducted extensive studies in order to achieve the above object, and realized the results in the present invention.

That is, according to the present invention, in the mold width change control method of the slab continuous casting equipment, which adjusts the moving amount and the tilt angle of the mold short side wall to change the mold width, the tilt angle of the mold short side wall is adjusted. Is performed by using an optical fiber loop type angular velocity sensor provided on the short side wall.

Further, the present invention is mounted on a molten steel continuous casting machine equipped with a mold consisting of two short side walls and a long side wall facing each other, and the positions of the upper and lower parts of the short side walls are movable respectively. A driving mechanism, measuring means for measuring the position and inclination angle of the short side wall by the number of rotations of the motor, and an operation indicator for instructing the driving mechanism the movement amount of the short side wall based on the measured value. In the mold width change control device of the slab continuous casting equipment, a sensor unit composed of an optical fiber loop attached to the short side wall as a means for measuring the inclination angle, and a light emitting unit for sending light to the optical fiber loop. And an amplifier unit incorporating a light receiving unit that receives light that has passed through the optical fiber loop and outputs the information to the operation instructing unit,
A mold width change control device for a slab continuous casting facility, which is provided with an optical path formed of an optical fiber that conveys light between them.

According to the present invention, even if there is a magnetic field in the vicinity of the position where the inclination of the short side wall is measured, the inclination angle of the moving short side wall can be measured more accurately and more stably than before. . As a result, the breakout frequency of the solidified shell and the mold wall due to the abnormal inclination of the short side wall is reduced, the operation is stabilized, and the productivity of the steel slab is improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

First, the overall structure of an example of a conventional mold width change control device for a slab continuous casting facility is shown. It is composed of two short side walls and a long side wall facing each other and injected molten steel. And a magnetic field generator for adjusting the flow state of the molten steel. And
As shown in FIG. 1, the upper and lower ends of the short side wall 13 are moved along the long side wall (not shown) by the drive shaft 15 and the motor 16 to change the position of the short side wall. Then, while changing the width of the mold, the rotation speed of the motor 16 is measured through the upper and lower two pulse generators 17, the width direction position of the short side wall is obtained, and the difference between the two is input to the calculator 14. Thus, the vertical tilt angle of the short side wall 13 is obtained.

In the present invention, as shown in FIG. 1, in the width change control device having such a structure, the sensor section 8 for detecting the inclination angle of the short side wall 13 and the entrance and exit of light to and from the sensor section 8 are provided. The amplifier section 9 for performing the above, and the optical fiber 10 for carrying the light between the sensor section and the amplifier section are added.

The added important part of the present invention is, as schematically shown in FIG. 2, a light emitting section 11, an optical path (outgoing path) 10 by an optical fiber, a sensor section 8 in which the optical fiber is looped, an optical path (return path). ) 10 'and the light receiving portion 12. Here, the light emitting unit 11 and the light receiving unit 12 are incorporated in the amplifier unit 9 shown in FIG. 1, and are installed in a place sufficiently away from the angular velocity detection position of the short side wall and not affected by the magnetic field,
The optical fiber 10 connects the sensor unit 8. The sensor portion 8 is the back surface of the short side wall 13 (the side not in contact with the molten steel).
It is fixed to and moves together with the short side wall. The sensor unit 8 has the same principle as a so-called “optical fiber gyro” that detects the angular velocity of an object by the Sagnac effect. In the present invention, the sensor unit 8 is made of only an optical fiber, The conversion of the signal from electricity to electricity is performed by the amplifier unit 9, and the amplifier unit 9 detects the angular velocity of the short side wall 13 by the sensor unit 8 and outputs it as an electric signal to the calculator 14 shown in FIG. In this computing unit 14, the inclination angle of the short side wall is calculated by integrating the above angular velocity with time. Here, the Sagnac effect (Sagn
The term “ac effect” means that there is a difference between the time taken for the light to make one turn along the rotation direction and the time taken for the light to make one turn in the opposite direction in the rotating coordinate system. For example, the optical fiber
In the loop, if A is a light emitting portion and B is a light receiving portion, the loop-shaped fiber lengths a and b are the same length. When the sensor (= optical fiber loop) is stationary under such a condition (see FIG. 4), the light emitted by A follows the respective routes of a and b and arrives at B at the same time. On the other hand, when the sensor is rotating in the direction of the arrow as shown in FIG.
The light emitted in 2 passes through two optical paths a and b and arrives at B at the same time. However, when the optical path itself is rotating, the actual light receiving section moves to B '. Regardless of this rotation of the optical path, the two lights reach B in FIG. 5B at the same time (Sagnac effect), so that in the actual light-receiving section B ′, the light passing through the optical path of a is Compared to the light passing through the optical path, it will be sent and arrive. Since this time difference is determined by the rotation angle, the rotation speed can be known by measuring the time difference, and the rotation angle can be known by integrating this with time.

As described above, in the width change control method and control device for the slab continuous casting equipment according to the present invention, it becomes possible to monitor the movement status and inclination of the short side wall 13 during the width change in real time. It becomes possible to immediately take emergency measures against the operation (forced termination of width change, deceleration of molten steel casting speed) before the breakout of the solidified shell and the mold wall.

As described above, according to the present invention, since the signal system in the vicinity of the mold is made entirely of light, even in a mold with a magnetic field, it is stable without being affected by the magnetic field, and the short side wall is stable. The inclination of can be measured accurately. Further, since light is used, there is no mechanically movable part, and even if a mold vibrating device is used, the response speed can be increased without being affected by vibration. Further, it becomes possible to constantly monitor the inclination angle of the short side wall during the width change, and it is possible to prevent the occurrence of breakout of the solidified shell or the mold wall due to the poor inclination angle. In addition, since the work of measuring the inclination of the short side wall in the preparation period for casting is unnecessary, the facility operating rate can be improved.

[0019]

EXAMPLE A mold width changing control device according to the present invention was applied to a continuous casting facility of a steelmaking plant having two 235 ton bottom blowing converters. The same device as that shown in FIG. 1 was used for the device. The continuous casting facility is a 2-strand vertical bending type continuous casting machine, and the casting speed is 0.3 to 2.0 m.
/ Min. In addition, a static magnetic field of 0.1 T is applied to the mold at the height position of the meniscus (surface of molten steel in the mold) and the position below the lower end of the dipping nozzle to control the flow of molten steel. went.

As a result, the behavior of the short side wall during the width change can be constantly monitored, and the casting during the width change can be remarkably stabilized. In addition, the breakout frequency of solidified shells and mold walls during width change was significantly reduced compared to the past. Furthermore, it is possible to eliminate the work of manually measuring the inclination of the short side wall between the operations (casting preparation period), and the time between castings and the load on the operator can be reduced.

More specifically, the frequency of breakouts due to the abnormal inclination of the short side wall is 0.5 per year as compared with the conventional case.
%, The work load of the operator between operations was reduced by 5%, and the time between castings was shortened by an average of 0.5 minutes.

[0022]

As described above, according to the present invention, even if there is a magnetic field in the vicinity of the position where the inclination angle of the short side wall is measured, the inclination of the short side wall during movement is more accurate and stable than before. The angle can be measured. As a result, the breakout frequency of the solidified shell and the mold wall due to the abnormal inclination of the short side wall is reduced, the operation is stabilized, and the productivity of the steel slab is improved.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the entire width change control device for a continuous casting mold according to the present invention.

FIG. 2 is a diagram showing means for measuring an angular velocity of a short side wall adopted in a width change control device for a continuous casting mold according to the present invention.

FIG. 3 is a transverse sectional view for explaining a general continuous casting machine.

FIG. 4 is a schematic diagram showing that the optical fiber loop is in a stationary state.

5A and 5B are schematic diagrams for explaining a difference in traveling of light during rotation of an optical fiber loop, where FIG. 5A is a stationary state and FIG.
Represents the rotation state.

[Explanation of symbols]

1 ladle 2 Molten steel 3 tundish 4 molds 5 solidified bodies 6 cooling zones 7 roller group 8 sensor section 9 Amplifier section 10 optical fibers 11 Light emitting part 12 Light receiving part 13 Short side wall 14 Operation indicator 15 drive shaft 16 motor 17 pulse generator

Claims (2)

[Claims] 1. A mold width change control method for a slab continuous casting facility in which a moving amount and a tilt angle of a short side wall of a mold are adjusted to change a mold width, wherein the tilt angle of the short side wall of the mold is adjusted. A mold width change control method for a slab continuous casting facility, characterized by using an optical fiber loop type angular velocity sensor provided on a side wall. 2. A drive mechanism which is attached to a molten steel continuous casting machine equipped with a mold comprising two short side walls and a long side wall facing each other, and which makes the upper and lower positions of the short side walls movable. Slab continuous casting formed by a measuring means for measuring the position and the inclination angle of the short side wall by the number of rotations of the motor, and an operation indicator for instructing the drive mechanism to move the short side wall based on the measured value. In a mold width change control device for equipment, as a means for measuring the tilt angle, a sensor unit including an optical fiber loop attached to the short side wall, a light emitting unit for sending light to the optical fiber loop, and the optical fiber A slab characterized by being provided with an amplifier unit incorporating a light-receiving unit for receiving light that has passed through the loop and outputting the information to the operation indicator, and an optical path formed of an optical fiber for carrying light between them. Communicating Casting equipment for mold width change control device.