KR20180006727A - Apparatus for measuring bending amount of continuous casting slab - Google Patents

Abstract

Disclosed is a device for measuring a bending amount of continuous casting slab, accurately measuring a bending amount in the longitudinal direction regardless of a change of the length and a position of the slab which is finished to be continuously casted. According to the disclosed present invention, the device for measuring a bending amount of continuous casting slab comprises: a laser radiation unit installed in an upper portion of a roller table where the slab is placed to be moved to visually display the bending amount in the longitudinal direction of the slab to radiate laser in the longitudinal direction of the slab; a detection unit capturing an image of the slab where the laser is radiated from the laser radiation unit to be transmitted; and a calculation unit converting the bending amount in the longitudinal direction of the slab based on the laser image of the slab transmitted from the detection unit.

Description

[0001] Apparatus for measuring bending amount of continuous casting slab [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending amount measuring apparatus for a performance slab, and more particularly, to a bending amount measuring apparatus for a bending amount measuring apparatus of a performance slab capable of accurately measuring a bending amount in the longitudinal direction, .

As is well known, the molten steel introduced in the steel making furnace is made of slab or the like through a continuous casting (hereinafter, referred to as 'performance') facility, and then rolled to form a steel plate coil .

At this time, a scale, that is, a defect is generated on the surface of the slab obtained through the continuous casting, and the scale of the surface of the slab obtained through the casting process is usually removed using a heating furnace and a scarfing machine.

However, when the slab is charged into the heating furnace and the scarping machine, scratches on the slab and breakage of the equipment may be caused due to interference between the slab and the peripheral equipment. This is due to the bending of the slab, because the amount of bending is large enough to cause interference with the heating furnace and the gate of the scarifying machine. Therefore, in the ordinary continuous casting step, the process of controlling the amount of bending is performed without advancing the slab directly to the next step.

Here, as a applicable technique, a method of measuring the amount of bending of the slab in the longitudinal direction by installing a laser array in the longitudinal direction on the slab / upper portion may be most common. However, this method is practically difficult to apply because the slab conveying crane always moves on the slab upper / upper part.

Therefore, as shown in Fig. 1, one laser distance meter 1 is installed so as not to interfere with peripheral equipment, and the amount of bending of the slab S is measured.

However, according to this method, as shown in Fig. 2A, as the length of the slab S changes, the portion of the slab S without bending is measured, or as shown in Fig. 2B, There is a problem in that the accuracy of the measured value is deteriorated by measuring the portion of the roll table 2 which is not provided.

On the other hand, in order to accurately measure the amount of slab bending, a method of calculating the bending amount of the slab by measuring the slab image on the side of the roller table and calculating the height of the slab image on the basis thereof is proposed in Korean Patent Publication No. 10-0920566 .

However, since this method also requires the image measuring device to be installed near the roller table, it may cause interference with other operations, and measurement time is increased because it is measured while moving.

(Patent 001) Korean Patent Publication No. 10-0920566 (Patent 002) Korean Patent Application Laid-Open No. 10-2014-0065106

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method of accurately measuring the amount of bending of a slab in a short time And it is an object of the present invention to provide a bending amount measuring device for a performance slab.

According to another aspect of the present invention, there is provided an apparatus for measuring a bending amount of a performance slab for measuring a bending amount in a longitudinal direction of a finished slab, A laser irradiating unit installed on an upper portion of a roller table on which the slab is moved to visually display an amount of the slab; A laser beam irradiating unit for irradiating a laser beam onto the slab; And a calculation unit for converting the amount of bending in the longitudinal direction of the slab based on the laser image of the slab transferred from the tacking unit.

In the apparatus for measuring the amount of bending of a performance slab according to the present invention, the laser irradiation unit may include a line laser irradiated with a green laser over a half of the entire length of the roller table, At an angle of 90 DEG or less with respect to the slab surface.

In the apparatus for measuring a bending amount of a performance slab according to the present invention, the tacking portion may include an area CCD camera, and the area CCD camera may be installed on a side surface of the roller table.

In the apparatus for measuring bending amount of a performance slab according to the present invention, the tacking unit may further include a filter installed in the area CCD camera and transmitting only a green color band.

According to the present invention, the amount of bending of the slab can be accurately measured within a short time without being influenced by the change in length of the slab, as well as the position of the slab.

Therefore, the present invention can prevent scratching of the slab due to interference with equipment in the subsequent slab scarfing process, thereby improving the quality of the slab and also protecting the facility by preventing the interference between the slab and the equipment . In particular, in recent years, as the production of high-grade steels increases, the scarfing process is increasingly applied to improve the surface quality, and it is possible to secure the quality of slabs as well as the facility protection effect through accurate measurement of the slab bending amount.

1 is a sectional view for explaining a bending amount measuring apparatus of a conventional performance slab;
FIGS. 2A and 2B are cross-sectional views for explaining a problem of a bending amount measuring method of a conventional performance slab;
3 is a perspective view illustrating a bending amount measuring apparatus for a performance slab according to an embodiment of the present invention.
FIGS. 4A to 4C are diagrams illustrating a method of measuring a bending amount of a performance slab according to an embodiment of the present invention, And line laser image after image processing of high temperature hot slab image.
FIG. 5B is an image of a slab image inspected by an area CCD camera of an apparatus for measuring a bending amount of a performance slab according to an embodiment of the present invention. FIG.
FIG. 5B is a line laser image in which the image of FIG. 5A is image-processed. FIG.
6A to 6D are views for explaining a method of extracting a laser line of an apparatus for measuring the amount of bending of a performance slab according to an embodiment of the present invention.
7A and 7B are schematic views for explaining a method of calculating a slab bending amount using a bending amount measuring apparatus for a performance slab according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Here, the shapes and thicknesses of the components in the respective drawings may be exaggerated for clarity of description of the present invention, and the same members in the drawings are given the same reference numerals. It should also be noted that while the description of the present invention has been made publicly known, it is not described herein to avoid confusion in the description of the present invention. In addition, although the target facility is described as a performance facility in the embodiment of the present invention, the present invention is not limited thereto, and it is also possible to apply the device of the present invention to facilities other than the performance facility.

3 is a cross-sectional view illustrating a bending amount measuring apparatus for a performance slab according to an embodiment of the present invention.

As shown in the figure, the apparatus 100 for measuring the bending amount of the performance slab according to the embodiment of the present invention may include a laser irradiation unit 10, a flaw inspection unit 20, and a calculation unit 30.

The laser irradiation unit 10 is provided to visually display the amount of slab bending in the longitudinal direction and may include a line laser 12 capable of irradiating a laser in the longitudinal direction of the slab S. [ This line laser 12 is laser-irradiated in the form of a line. For example, when the slab S is placed on a portion of the roller table 2 located at the front end of the scarfing machine, the longitudinal direction of the slab S is defined as So that the laser beam is irradiated at the central portion in the width direction.

An interference facility such as a crane (not shown) for moving the slab S to the roller table 2 may be installed on the upper portion of the roller table 2, (2). In addition, the line laser 12 is installed at a position at an angle of 90 DEG or less with respect to the slab surface. Although not shown, the line laser 12 can be installed above the leading edge of the roller table 2 by using a support and a bracket.

In addition, the line laser 12 can be configured to be irradiated over half the length of the entire roller table 2 so as to be able to irradiate the slabs S of all lengths. This is made in view of the fact that the bending of the slab S by heat is performed by back and forth symmetry.

In addition, in the slab S to be charged into the scarping machine, there may be a hot slab having a high temperature, and in such a hot slab with a high temperature there may be a problem in detecting a laser irradiated with red light, A green laser is used to prevent the line laser 12 from being affected by red light.

The laser irradiation unit 10 may include a first controller 14 and a cable 16 for applying an operation signal to the line laser 12. Here, although not shown, the first controller 14 may be connected to the main control system for controlling the overall driving of the bending amount measuring apparatus 100 of the performance slab by wired or wireless. Alternatively, the first controller 14 may not be provided, and in this case, the line laser 12 may be directly or wirelessly connected to the main control system.

The tacking unit 20 is provided to detect a longitudinal bending image of the slab S visually displayed by the line laser 12 of the laser irradiating unit 10. The area CCD camera 22). Particularly, in the embodiment of the present invention, since the tacking portion 20 must always be able to detect the front half of the slab S, the area caddy camera 22 of the tacking portion 20 is located on the side of the roller table 2 Respectively. Also, the area CCD camera 12 in the embodiment of the present invention preferably has a high resolution because the minute bending amount of the slab S can be measured.

In addition, in the embodiment of the present invention, the green CCD 24, which transmits only the green color band, is applied to the area CCD camera 22 of the inspection unit 20 so that laser scanning can be performed on all the slabs S .

Specifically, FIG. 4A shows that a high-temperature hot slab image picked up from an area CCD camera in the case where a green filter is not used can not grasp a line laser irradiated on the hot slab S1 at high temperature can see.

On the other hand, FIGS. 4B and 4C show a high-temperature hot slab image taken from an area CCD camera in the case where a green filter is used and a laser line image obtained by image processing, It can be seen that the laser L is irradiated to the central portion in the width direction along the direction of the hot slab S1 and the laser line L / L after the image processing is obtained from the image of the hot slab S1.

Although not shown, the inspection unit 20 according to the embodiment of the present invention may further include a second controller 26 and a cable 28 for controlling the operation of the area CCD camera 22 , The second controller 26 may be connected to the calculation unit 30 to be described later by wire or wireless. Alternatively, the second controller 26 may not be provided, and in this case, the area CCD camera 22 may be directly connected to the calculation unit 30 by wire / wireless.

The calculation unit 30 is provided to calculate the amount of bending of the slab S based on the image transmitted from the area CCD camera 22 of the tacking unit 20. [ The calculation unit 30 may include an arithmetic unit and a display unit. The calculation unit 30 may extract the bending peak and the lowest point from the image transmitted by the area CCD camera 22, Is converted.

Particularly, since the calibrating operation for the slab S to be sent to the scarifying step is performed based on the bending amount of the slab S converted by the calculating part 30, interference with the equipment in the subsequent scarping step causes the slab S S) can be protected as well as scratches.

Hereinafter, a method of measuring the amount of slab bending using the apparatus 100 for measuring a bending amount of a performance slab according to an embodiment of the present invention will be briefly described.

First, when the slab is put on the roller table and stopped, the line laser of the laser irradiation unit is turned on to irradiate the laser along the slab length direction at the center in the slab width direction. At this time, the line laser irradiates from the slab head, that is, from the slab start point to the center portion of the slab substantially.

In this state, an image of the slab irradiated with the line laser is obtained by imaging the slab irradiated with the line laser with the area CCD camera of the flaw area. At this time, a line of the line laser irradiated to the slab should be extracted from the slab image. Since the laser line always irradiates the fixed portion, in order to perform efficient image processing, as shown in FIG. 5A, Only a certain region in which the line is always located is concentrated and extracted. This is set in consideration of the fact that the normal amount of slab bending is less than a certain amount. In Fig. 5A, reference numeral I / A denotes an image processing area.

Here, in order to measure the amount of bending of the slab, it is necessary to accurately extract the line of the irradiated laser. Since the laser line is not clearly expressed due to the slab surface condition, surrounding illumination condition, There may be cases where it does not. Therefore, image processing is required for accurate laser line extraction, which can be obtained by image conversion of the area CCD camera.

Specifically, the first important thing is to accurately detect the head part of the slab, that is, the starting part, and start extracting the line from that part. The head detection is performed such that a threshold value indicated by white of a monochrome image is lowered so that many gray levels are displayed in white so that most bright portions are displayed in white as shown in FIG. 6A. Then, set the rectangle area at the roll center position and calculate the white level ratio in the area from left to right. At this time, when the white level ratio becomes 80% or more, the movement of the level calculation area is stopped, and the black and white boundary in the level calculation area is set as the head of the slab.

Next, as shown in FIG. 6B, a laser line is extracted from an image processing area I / A previously set in consideration of a preset bending measurement area, that is, the maximum size at which normal bending occurs, / A from the slab head to the right side and the number of pixels less than 10 is removed as a discontinuous point, the shape of the line L as shown in FIG. 6C is left, and the remaining lines are moved from left to right If the end points are connected to each other, only the laser line L / L by bending is left as shown in FIG. 6D, and the bending amount of the slab can be calculated according to the degree of deformation of the laser line L / L.

Next, when the image scanned from the CCD image sensor of the inspection unit is transmitted to the calculation unit, the calculation unit extracts the highest point and the lowest point from the image-processed line laser (L / L) as shown in FIG. 5B.

As a result of the extraction of the highest point and the lowest point, it is recognized that upward bending occurs when the order is formed from a high point to a low point as shown in FIG. 7A, and when it is formed from a low point to a high point as shown in FIG. 7B, And the bending amount is converted. At this time, the conversion of the bending amount can be performed by varying a predetermined height by using a test plate determined in advance at the measurement position and finding the relationship between the height and the position where the line laser is scanned in the area CCD camera area Do.

Thereafter, the slab to be sent to the scarifying process is calibrated using water cooling based on the measured bending amount of the slab, and when the bending amount of the slab subjected to the calibrating process is again measured, This slab is sent to the scarfing process.

Here, in the calibration work, for example, when the lower cooling water injection nozzle and the upper cooling water injection nozzle are provided on the lower and upper portions of the roll table on which the slab is to be placed, the bending amount of the slab calculated from the calculation section A signal is sent to the cooling water valve control device to open the valve, and cooling water is supplied from the lower cooling water injection nozzle or the upper cooling water injection nozzle to the slab.

That is, when the upward bending occurs, the valve of the lower cooling water injection nozzle is opened. When the downward bending occurs, the valve of the upper cooling water injection nozzle is opened. Since all the slabs are at a higher temperature than the cooling water, , And the bending is corrected by the top-bottom temperature unevenness shape of the slab. In addition, the amount of bending is continuously measured while the cooling water stock is progressing. When the amount of bending is within the control range, a signal is sent to the cooling water valve control device to close the valve and complete the calibration work.

By controlling the amount of bending of the slab in this way, the slab charged in the scarfing process is prevented from coming into contact with the scarfing nozzle, thereby preventing scratches on the slab surface and also protecting the equipment.

In other words, when the apparatus for measuring the amount of bending amount of the performance slab according to the embodiment of the present invention is used, the longitudinal bending amount of the slab can be accurately measured irrespective of the position and length variation of the slab, , For example, interference between the scarfing nozzle and the slab is prevented, thereby securing the quality of the scabbed slab and protecting the facility.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it is to be understood that the invention is not to be limited to the disclosed embodiments, but, on the contrary, And can be modified by those skilled in the art.

2: roller table 10: laser irradiation part
12: line laser 14: first controller
16, 28: cable 20:
22: Area CCDD camera 24: Green filter
26: second controller 30: calculating section
S: Slab S1: High temperature hot slab
L: Laser L / L: Line laser
100: Measuring device of the bending amount of the performance slab

Claims (6)

An apparatus for measuring a bending amount of a performance slab for measuring a bending amount in a longitudinal direction of a finished slab,
A laser irradiation unit installed on an upper portion of a roller table on which the slab is moved so as to visually display a longitudinal bending amount of the slab and irradiating a laser in a longitudinal direction of the slab;
A laser beam irradiating unit for irradiating a laser beam onto the slab; And
A calculation unit for converting the amount of bending in the longitudinal direction of the slab based on the laser image of the slab transferred from the tacking unit;
And a bending amount measuring device for measuring the bending amount of the performance slab.
The method according to claim 1,
Wherein the laser irradiating unit includes a line laser irradiated with a green laser over a half length of the entire length of the roller table.
3. The method of claim 2,
Wherein the line laser of the laser irradiating unit is installed at a position above the entrance end of the roller table at an angle of 90 DEG or less with respect to the slab surface.
The method according to claim 1,
Wherein the bending amount measuring unit includes an area CCD camera.
5. The method of claim 4,
Wherein the area CCD camera is installed on a side surface of the roller table.
5. The method of claim 4,
Wherein the inspection unit further comprises a filter installed in the area CCD camera and transmitting only a green color band.

Images