KR20120045313A - Apparatus and method for measuring level of mouldflux - Google Patents

Abstract

PURPOSE: A device and a method for measuring a mold flux level are provided to stably measure a mold level without a performance degradation by maintaining a fixed distance in the circumstance of high temperature, the dust etc. and to reduce error by manually measuring the mold level. CONSTITUTION: A device and a method for measuring a mold flux level comprises a laser driving unit(110) a mold level measuring unit(100). The laser driving unit irradiates a line laser. The mold level measuring unit is arranged to be adjacent to the laser driving unit, thereby photographing the liner laser on real time basis. The mold level measuring unit comprises an angel adjusting unit and support stand(140).

Description

Mold Flux Level Measuring Apparatus and Mold Flux Level Measuring Method {APPARATUS AND METHOD FOR MEASURING LEVEL OF MOULDFLUX}

The present invention relates to a mold flux level measuring apparatus and a mold flux level measuring method, and more particularly, to a method for measuring the level of the melt surface by measuring the flow of the melt surface in real time and measuring the thickness of the molten mold flux therefrom. will be.

In general, cast steel (generally slabs, billets, blooms, beam blanks, etc.) manufactured in a continuous casting apparatus is supplied with a molten steel in a liquid state from a ladle, and then molded through a tundish for storing the molten steel. While passing through, the solidification shell in the solid state is formed by the cooling action in the mold. The solidified shell in which the molten steel is cooled is solidified by the secondary cooling water sprayed from the spray nozzle while being guided by the guide roll installed in the lower portion thereof, and appears in the form of a cast iron in a completely solid state.

In the continuous casting operation of such steel, when molten steel is supplied into the mold, not only molten steel but also a subsidiary mold flux is introduced. Moldflux is a material that controls heat transfer between molten steel and mold and improves lubrication ability. Conventionally, the mold flux is introduced into a solid state such as powder or granules, melted by heat generated from molten steel supplied into the mold, and then forms a liquid layer. The liquid layer flows between the mold and the solidification shell and solidifies at the mold inner wall. A solid slag film was formed, and on the molten steel side, a liquid slag film was formed to control heat transfer between the molten steel and the mold and to improve lubrication ability. At this time, the molten slag is introduced between the solid slag film and the solidification shell, the mold flux attached to the mold is formed in a form protruding into the mold, which is called slag bear. The slag bearing prevented the molten slag from flowing between the mold flux film and the solidification shell, thereby reducing the lubrication ability between the slab and the mold, and increasing the break-out occurrence in which the solidification shell was broken by friction with the mold. As the thickness of the liquid mold flux becomes uneven due to the slag bearing, the shape of the solidification shell in the mold becomes uneven, which causes surface cracks, which also causes serious problems as the casting speed is increased.

In order to solve this problem, a continuous casting apparatus and a method capable of injecting a molten mold flux into a mold over the entire duration of the continuous casting process have been proposed. The molten mold flux is almost transparent to wavelengths between 500 and 4,000 nm, and radiant heat transfer is increased to radiate molten steel because the radiation waves emitted from molten steel pass easily. For this reason, when the casting process progresses and a predetermined time elapses, a problem arises in that the molten steel of the molten steel solidifies, and thus, the continuous continuous casting process cannot be performed. A certain amount of free carbon is applied onto the molten mold flux from time to time during the casting operation to keep the surface warm.

It is important to know the level (thickness) of the mold flux layer because the supply amount of the mold flux is determined in accordance with the operating conditions such as the casting speed and the hot water temperature during the casting process. If the thickness of the molten mold flux layer is taken thinly during operation, breakout occurs due to the mixing of the mold flux, and if the thickness of the mold flux layer is too thick, the consumption is reduced and the operation becomes unstable. Conventionally, ultrasonic measurement, direct probe, and microwave methods have been used to measure the thickness of the mold flux. However, problems with performance and durability, such as malfunction or damage of the device in high temperature, dust and vibration environments around the mold, there was. In addition, there was a problem that the operator has to approach the mold for a long time measurement.

The present invention provides a mold flux level measuring apparatus and a measuring method which can measure the mold flux thickness by stably measuring the level of the hot water level without maintaining a certain distance in an operating environment such as high temperature and dust and without degrading performance such as error and malfunction. .

The present invention provides a mold flux level measuring apparatus and a measuring method which can accurately measure the mold flux without the operator directly probe the mold flux, and can reduce the error caused by manual measurement.

The present invention also provides a mold flux level measuring apparatus and a mold flux level measuring method capable of detecting the level of the mold flux by measuring the level of the hot water surface in real time.

The mold flux level measuring apparatus according to the present invention includes a water level measurement unit including a laser driver for irradiating a line laser and a photographing unit for photographing a line laser irradiated adjacent to the laser driver in real time.

It is preferable that the water level measurement unit further includes an angle adjusting unit for mounting the laser driver and the photographing unit to adjust the vertical angle, and a support for supporting the angle adjusting unit.

In the mold flux level measuring apparatus according to the present invention, a measuring unit for converting the length of the line laser photographed by the photographing unit to a pixel value, and measuring the actual length in accordance with the pixel value.

In the mold flux level measuring apparatus according to the present invention, a display unit for displaying in real time the image taken by the photographing unit, the pixel value and the measured actual length converted in the measurement unit.

Method for measuring the thickness of the mold flux supplied to the molten steel charged in the mold according to the present invention comprises the steps of measuring the length (A) from the reference line displayed on the upper surface of the mold to the hot water surface; Measuring the length B from the baseline to the upper surface of the molten steel; And subtracting the actual length A of the measured predetermined section from the length B from the baseline to the upper surface of the molten steel to measure the mold flux level.

In the mold flux level measuring apparatus according to the present invention, the step of measuring the length (A) from the reference line to the tap surface is irradiated with a line laser on the tap surface in the mold; Photographing the irradiated line laser; Converting the line laser length of the predetermined section photographed by the photographing unit to a pixel value; It is preferable to further include a step of converting the pixel value to the actual length (A) to measure the surface level.

In the mold flux level measuring apparatus according to the present invention, when the free carbon is applied to the upper surface of the mold flux, measuring the thickness (C) of the free carbon coating layer; further comprising, in the step of measuring the mold flux level It is preferable to further subtract by the thickness (C) of the carbon coating layer measured from the length (B) from the baseline to the upper surface of the molten steel to measure the mold flux level.

In the mold flux level measuring apparatus according to the present invention, the step of measuring the length (A) from the reference line displayed on the upper end of the mold inner surface to the water surface is preferably measured in real time.

According to embodiments of the present invention, the present invention can stably measure the water level without maintaining a certain distance in an operating environment such as high temperature and dust, without degrading an error or malfunction. In addition, by maintaining a certain distance in the operating environment, such as high temperature, dust, it is possible to improve the durability of the device.

 The operator can accurately measure the mold flux without directly probing the mold flux and can reduce the errors caused by manual measurement of the floor height.

By measuring the level of the hot water surface in real time, the level of the mold flux can be detected throughout the process.

In addition, the operator does not need to approach the mold for a long time to measure the operation time can be shortened, and safe operation can prevent the operation accident and industrial accidents.

1 is a conceptual diagram illustrating a surface level measuring unit of a mold flux level measuring apparatus according to an exemplary embodiment of the present invention.
2 is a conceptual diagram schematically showing a mold flux level measuring apparatus according to an embodiment of the present invention.
FIG. 3 is a conceptual diagram illustrating measuring the surface of a water level through a mold flux level measuring apparatus according to an exemplary embodiment of the present invention.
Figure 4 is an enlarged photograph of measuring the level of the hot water through the mold flux level measuring apparatus according to an embodiment of the present invention.
5 is a conceptual diagram illustrating a method of measuring the surface level of a mold flux level measuring apparatus according to an exemplary embodiment of the present invention.
FIG. 6 is a graph relating to the surface level of water measured by a mold flux level measuring device according to an exemplary embodiment of the present invention. FIG.
FIG. 7 is a graph comparing the measured level of the tap level measured by the mold flux level measuring device according to an embodiment of the present invention.

Hereinafter, a mold flux level measuring apparatus and a mold flux level measuring method using the same will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Like numbers refer to like elements in the figures.

1 is a conceptual diagram illustrating a water level level measuring unit of a mold flux level measuring apparatus according to an exemplary embodiment of the present invention, and FIG. 2 is a conceptual diagram schematically illustrating a mold flux level measuring apparatus according to an exemplary embodiment of the present invention. 3 is a conceptual diagram illustrating measurement of the tap surface level through the mold flux level measuring apparatus according to an embodiment of the present invention, and FIG. 4 is a level diagram of the tap surface level through the mold flux level measuring apparatus according to an embodiment of the present invention. It is an enlarged photograph of measuring.

First, the mold 10 will be described. In the continuous casting process, solidification of the cast steel is started first in the mold 10. The mold 10 is an apparatus for initially solidifying molten steel by receiving molten steel from a tundish (not shown) serving as a buffer in a continuous casting process. The mold 10 has a cupper for sidewalls to cool the molten steel. ) And a water jacket inserted into the coolant. The mold 10 is open at the top and has a space for accommodating molten steel. The mold 10 is composed of a plurality of side walls extending upwardly from the bottom surface, and generally consists of side walls of the long side portion and the short side portion, and the horizontal cross section has a rectangular shape. The mold shape is not limited thereto and is determined according to the size and shape of the product to be manufactured. In the embodiment of the present invention, the mold 10 as described above is illustrated.

In the initial solidification of molten steel, a subsidiary mold flux is added to control heat transfer between the molten steel and the mold and to improve lubrication ability. For smooth operation and surface quality of cast steel, it is necessary to know the injection amount of the mold flux, that is, the thickness of the mold flux layer. In the present invention, the molten metal level of the molten metal charged into the mold is first measured, and then the thickness of the mold flux layer is Measure it. A reference line 15 (refer to FIG. 3) is formed in the horizontal direction at the upper end of the inner wall surface of the mold 10 to determine the height of the water surface.

Referring to FIG. 1, a mold flux level measuring apparatus according to an exemplary embodiment of the present disclosure may photograph a laser driver 110 for irradiating a line laser and a line laser irradiated adjacent to the laser driver 110 in real time. It is configured to include a water level measurement unit 100 having a photographing unit 120.

In the mold flux level measuring apparatus according to the present invention, the surface level is measured using a laser and an imaging apparatus, and the thickness of the mold flux layer is measured by using a difference between the measured surface level (height) and the height of the molten steel. The apparatus for measuring the water level is the measuring unit 100.

The laser driving unit 110 is a device for irradiating a line laser. The laser driving unit 110 measures a shape of the tap surface by irradiating a line-shaped laser onto the tap surface in the mold 10 so that a line corresponding to the shape appears on the tap surface. When the laser in the form of a line is irradiated on the hot water surface (see FIG. 3), a shape corresponding to the surface on which the laser is formed is revealed. That is, as shown in FIG. 3, when the line lasers 5 and 6 are irradiated to the tap surface at a predetermined angle, the line laser is formed along the shape of the tap surface, and is folded at the point where the tap surface meets the inner wall of the mold 10. ) To form along the inner wall. At this time, it is preferable that the line laser 5 is irradiated at an inclined angle, not perpendicular to the hot water surface, and irradiated so that the line laser formed on the inner wall of the mold 10 is perpendicular to the ground. This is because the line laser 6 formed between the reference line 15 and the hot water surface should be perpendicular to the ground to easily grasp the height. The laser driver 110 may further include an intensity controller (not shown) for adjusting the intensity of the line laser to obtain an optimal image.

The photographing unit 120 is a device for photographing the irradiated line laser in real time, and is disposed adjacent to the laser driver 110. The photographing unit 120 photographs an area to which the line laser is irradiated so that the measurement unit 200, which will be described later, converts the length of the line laser into a pixel value. The photographing unit 120 detects the tandem and the line laser irradiated along the mold to obtain an image of the tandem and the mold. Acquisition of such an image may be implemented using a charge coupled device (CCD) camera. The CCD is composed of a circuit in which a plurality of capacitors are interconnected in pairs, and each capacitor in the circuit transfers the charge charged to the battery around the capacitor. A CCD is a chip in which photodiodes are gathered. When light shines on each photodiode, electrons are generated according to the amount of photons, which are grains of light. Image information that forms the screen is created. When the light of the line lasers 5 and 6 as shown in FIG. 4 is shined on the photographing unit 120, the photographing unit 120 reconstructs this information and sends the information to the measuring unit 200 and the display unit 300. The photographing unit 120 is not limited to a CCD camera, and any device capable of reconstructing an image by dividing a line laser can be variously selected. The photographing unit 120 is installed to form a predetermined angle (α) up and down with the laser driver 110 as shown in FIG. 1 to photograph the area irradiated with the line laser, and the photographing direction of the photographing unit 120 is laser It is not to be parallel to the laser irradiation direction of the drive unit 110, so that the line laser is photographed obliquely from the side so as to clearly photograph the point (M) where the line laser meets the inner wall of the mold 10.

An angle adjusting unit 130 may be further provided while allowing the laser driving unit 110 and the photographing unit 120 to adjust angles up and down. As shown in FIG. 3, the angle adjuster 130 tilts downward to easily irradiate the laser.

A support unit 140 may be further provided to support the angle adjuster 130 so that the water level measurement unit 100 is fixed to stably irradiate and photograph the laser. The support 140 is formed to extend in the longitudinal direction so that even if the surface level measurement unit 100 is installed at a distance spaced from the mold 10, the laser surface can be irradiated and photographed smoothly. The support 140 may be fixed to a tundish car for moving the tundish to a predetermined casting position, but is not limited thereto, and other structures spaced apart from the mold 10 may be considered.

The mold flux level measuring apparatus according to the present invention may further include a measuring unit 200. The measurement unit 200 converts the length of the line laser photographed by the photographing unit 120 into pixel values and measures the actual length according to the pixel values. When the photographing unit 120 images the line laser through the brightness of the light based on the captured image, the measurement unit 200 converts the imaged line laser into pixels. The number of pixels of the image formed by the section is determined with respect to the desired section length on the line laser. The length of the desired section is measured using the actual length of one pixel. For example, in this embodiment, the section to be actually obtained is the length A from the point M where the line laser meets the mold on the surface of the water to the reference line 15, so that the length A is 20 pixels. If the actual length per pixel is 1 mm, the actual length A to be obtained will be measured to 20 mm. A more detailed measuring method will be described later.

The mold flux level measuring apparatus according to the present invention may further include a display unit 300. The display unit 300 is a device which displays the image photographed by the photographing unit 120, the pixel value converted by the measurement unit 200, and the measured actual length in real time. To help you understand.

Referring to the drawings, the operation of the mold flux level measuring apparatus according to a preferred embodiment of the present invention and a method for measuring the mold flux level using the same will be described.

The molten steel 20 is charged into the mold 10, the molten mold flux 30 is introduced onto the molten steel 20, and, in some cases, the free carbon 40 for the mold flux to insulate the mold flux 30. The powder can be applied. In order to measure the thickness X of the mold flux 30 layer introduced during the playing process, as shown in FIG. 3, the length from the reference line 15 displayed on the upper surface of the mold 10 to the upper surface of the molten steel 20 ( B) and the thickness C of the free carbon layer 40 and the length A from the reference line 15 to the bath surface are measured. Then, from the length (B) from the reference line 15 displayed on the upper side of the mold 10 to the upper surface of the molten steel 20 to the thickness C of the free carbon layer 40 and from the reference line 15 to the hot water surface. By subtracting the length A, the thickness X of the layer of mold flux 30 can be obtained (ie, X = B-A-C).

 In order to measure the length A from the reference line 15 to the tap surface, the line laser is irradiated onto the tap surface in the mold 10 through the laser driver 110. As described above, the angle adjusting unit 130 tilts downward at a predetermined angle so that the line laser forms a predetermined angle not perpendicular to the water surface, and the line laser 6 formed on the inner wall is irradiated perpendicular to the ground. The line laser 5 advances in the laser advancing direction after meeting the hot water surface, and advances along the inner wall while crossing the mold line 10 to cross the reference line 15.

Photograph the line laser. In particular, the irradiated line laser is photographed centering on the line laser from the portion M to the reference line 15 which is bent while meeting the inner wall of the mold 10. FIG. 5 is a screen image of an area where a line laser is photographed and appears on the display unit 300, 5a is a line laser formed on a hot water surface, 6a is a line laser formed on an inner wall surface of a mold 10, and 15 is a reference line. . The line represented by the line laser 5a formed on the surface of the water is relatively smooth and minute bending due to impurities, bubbles, and free carbon powder present on the surface of the water, and the line laser 6a formed on the inner wall of the mold 10. The line shown by) is smooth. The line laser 5 draws an imaginary extension line 5b with respect to the unsmooth line, that is, a line laser 5a formed on the surface of the water so as to clearly expose the bent portion M while meeting the inner wall of the mold 10, and the line formed on the mold. An imaginary extension line 6b of a laser 5b, that is, a smooth line, is drawn to mark the intersection M of the two lines 5 and 6. Determine the number of pixels that make up the distance A from the intersection point M to the baseline 15, and use the number of pixels and the length per pixel to find the actual length A from the intersection point M to the baseline 15 Obtain At this time, the trajectory of the intersection point M may be identified to determine a change in the distance A from the intersection point M to the reference line 15, and thus the actual length A may be measured in real time.

The length B from the reference line 15 to the upper surface portion of the molten steel 20 is measured. In order to maintain the molten steel 20 charged in the mold 10 at a predetermined level, a device for grasping the height of the molten steel and controlling the input amount of the molten steel through the identified height is provided, thereby measuring the height of the molten steel. have. Specifically, the tumbled bottom for supplying molten steel to the mold 10 is provided with an immersion nozzle, and the molten steel is charged from the tundish into the molten steel through the immersion nozzle. A stopper is provided between the tundish and the immersion nozzle to control the tundish outlet opening to adjust the amount of molten steel charged into the mold. In order to detect the amount of molten steel charged into the mold 10, a molten steel detector is disposed above the mold, and the amount of molten steel introduced into the mold is controlled by controlling the stopper according to the signal detected by the molten steel detector. In this case, the molten steel detection device may be selected from various devices such as gamma ray (γ-ray) or Eddy Current Level Meter (ECLM) using Eddy current. The height of the uppermost surface of the molten steel can be known from the molten steel detector, and through this, the length B from the reference line 15 to the upper surface of the molten steel 20 can be obtained.

Then, the thickness of the free carbon layer 40 coated on the mold flux 30 is measured. The thickness of the free carbon layer 40 may be determined by inserting a manual probe into the mold 10, but the volume, that is, the thickness of the free carbon layer 40 applied on the mold flux through the weight and density of the injected free carbon. It can be seen. In addition, the height of the free carbon layer 40 may change due to the slight decarburization, and the approximate change in the thickness of the free carbon layer 40 is calculated through a calculation formula. For example, when 1.2 kg of free carbon is charged into a mold 10 having a rectangular cross section of 2000 mm long and 200 mm short, the free carbon layer is applied to a thickness of 10 mm, and the height is increased at a speed of 0.41 mm / min during continuous casting. Decreases. Through this calculation, the thickness of the free carbon layer 40 coated on the mold flux can be obtained.

Measuring the length from the baseline 15 to the bath surface (A), measuring the length (B) from the baseline 15 to the molten steel upper surface portion, and measuring the thickness (C) of the free carbon layer in order It is irrelevant and any step can be measured first.

Length (B) from the reference line 15 displayed on the upper side of the mold 10 to the upper surface of the molten steel 20, the thickness C of the free carbon layer 40, and the length from the reference line 15 to the bath surface A ), The thickness (X) of the layer of mold flux 30 can be obtained by calculation (X = B-A-C).

FIG. 6 is a graph of a tap surface level measured by a mold flux level measuring apparatus according to an embodiment of the present invention, and FIG. 7 is a tap surface level measured by a mold flux level measuring apparatus according to an embodiment of the present invention; This is a graph comparing the measured water level.

The x-axis is the operating time (unit: minute), the y-axis is the thickness of the mold flux (unit: mm), a is the thickness of the mold flux measured in units of 1 minute according to this embodiment, and b is 5 minutes according to this embodiment. The thickness of the mold flux measured in units, c is the thickness of the mold flux measured in units of 10 minutes according to the present embodiment, and d represents the thickness of the mold flux actually measured.

As can be seen in Figure 6, there is no significant difference between the results measured in units of 1 minute and the results measured in units of 10 minutes, it is more efficient to measure the thickness of the mold flux in units of 10 minutes. As can be seen in Figure 7, according to the present embodiment there is no significant difference between the thickness of the mold flux and the thickness of the mold flux actually measured in units of 10 minutes. Thus, according to the present invention, it is possible to accurately measure the thickness of the mold flux.

The embodiments and drawings attached to this specification are merely to clearly show some of the technical ideas included in the present invention, and those skilled in the art can easily infer within the scope of the technical ideas included in the specification and drawings of the present invention. Modifications that can be made and specific embodiments will be apparent that both are included in the scope of the invention.

5, 6: line laser 10: mold
15: reference line 20: molten steel
30: mold flux 40: free carbon
100: water level measurement unit 110: laser driving unit
120: photographing unit 130: angle adjustment unit
140: support

Claims (8)

Mold flux level measuring device comprising a; and a laser driving unit for irradiating a line laser and a photographing unit for photographing the line laser irradiated adjacent to the laser driver in real time.
The method according to claim 1,
The water level measurement unit
Mold flux level measuring device further comprises an angle adjusting unit for adjusting the vertical angle and the laser driving unit and the photographing unit, and a support for supporting the angle adjusting unit.
The method according to claim 1,
A measuring unit converting the length of the line laser photographed by the photographing unit into a pixel value and measuring an actual length according to the pixel value;
Mold flux level measuring apparatus comprising a.
The method according to claim 3,
A display unit displaying the image photographed by the photographing unit, the pixel value converted by the measuring unit, and the measured actual length in real time;
Mold flux level measuring apparatus comprising a.
In the method for measuring the thickness of the mold flux supplied to the molten steel charged in the mold,
Measuring a length A from the reference line displayed on the upper side of the mold inner surface to the tap surface;
Measuring a length B from the baseline to the upper surface of the molten steel; And
Measuring a mold flux level by subtracting the actual length A of the measured predetermined section from the length B from the reference line to the molten steel upper surface portion;
Mold flux level measurement method comprising a.
The method according to claim 5,
Measuring the length (A) from the baseline to the water surface
Irradiating the line laser on the surface of the mold;
Photographing the irradiated line laser;
Converting a line laser length of a predetermined section photographed by the photographing unit to a pixel value;
Measuring the surface level by converting the pixel value into an actual length A;
Mold flux level measurement method comprising a.
The method according to claim 5,
When the free carbon is applied to the upper surface of the mold flux, measuring the thickness (C) of the free carbon coating layer;
In the step of measuring the mold flux level
The mold flux level measuring method for measuring the mold flux level by further subtracting by the thickness (C) of the carbon coating layer measured from the length (B) from the reference line to the upper surface of the molten steel.
The method according to claim 5,
Measuring the length (A) from the reference line displayed on the top of the mold inner surface to the tap surface is measured in real time mold flux level.

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