JPH10277912A - Surface flaw treatment method for steel piece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce mistake rate of a symbol mark and provide highly accurate surface flaw data by extracting the surface flaw data constituted of a flaw classification of the symbol mark and its position from image data. SOLUTION: When an inspector detects a surface flaw by examining the presence/absence of the surface flaw of a steel piece 10 by using a surface flaw detector or an inspection, the flaw classification is collated with a correspondence table so as to mark a detected position on the steel piece 10 by a corresponding symbol mark 11. Secondly, a television camera 12 is moved along the surface of the mounted steel piece 10 so as to photograph the steel piece 10 and the image data across its whole length is inputted in a controller 13. The controller 13 analyzes the image data and the position data so as to calculate the classification and the position of the symbol mark 11 on the image data so that the surface flaw data of the steel piece 10 composed of the position of the symbol mark 11, the flaw classification and an area of a part supported by the symbol mark 11 can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface flaw treatment for a steel slab which can accurately detect a sign indicating a surface flaw marked on the steel slab and efficiently treat the surface flaw portion. About the method.

[0002]

2. Description of the Related Art In many cases, cast steel pieces such as slabs, blooms and billets have surface defects (surface defects) such as cracks and pinholes on the surface thereof. Since such surface defects remain without being removed even by rolling of a steel slab, they cause a reduction in the yield of the final product. Therefore, since it is desirable to remove surface defects at the stage of the billet, by detecting the surface defects of the billet,
For example, the following methods (1) to (4) have been proposed as methods for performing a care treatment. JP-A-59-52735 discloses a method of irradiating a hot slab with visible light and detecting a surface defect of the slab from an image composed of self-emission from the slab and reflected light of illumination. . JP-A-59-154312 discloses an illuminating device for detecting a hot slab surface flaw, comprising a halogen lamp for illuminating the surface of a hot continuous casting slab, a reflecting mirror having an elliptical surface, and a cooling device. I have. JP-A-63-18255 discloses a method of detecting a surface flaw from an image of a slab surface at the time of scarfing. Japanese Patent Application Laid-Open No. H6-129995 discloses an illuminating device for illuminating a material to be inspected, a diffusion device for diffusing illumination light of the illuminating device, a photographing device for photographing an illuminated portion of the material to be inspected, and a photographed image or processed image An optical surface defect inspection apparatus provided with an image display device for displaying an image is described.

[0003]

However, the above-mentioned methods have the following problems. In the method described in JP-A-59-52735 for detecting a surface defect of a slab from an image of self-emission from a slab and reflected light of illumination, the uniformity of illumination light and the intensity ratio of self-emission and reflected light are appropriate. Otherwise, clear images cannot be obtained and defects cannot be detected. In the lighting device for detecting a hot slab surface flaw described in JP-A-59-154312, the illuminating light is reflected by a reflector to irradiate parallel light. Since the light is irradiated, a shadowed portion is formed due to the unevenness of the slab surface, and it becomes difficult to detect the surface flaw. In the method of detecting a surface flaw from the image of the slab surface at the time of scarfing described in JP-A-63-18255, a clear image of a defective portion cannot be obtained due to dust or high temperature generated at the time of scarfing, Further, it is necessary to protect the photographing device from high-temperature gas, dust and the like generated at the time of scarfing, and there is a problem in cost and maintenance. In an optical surface defect inspection apparatus having an illuminating light diffusing device described in Japanese Patent Application Laid-Open No. 6-129995, there is a case where a striped pattern due to poor cutting and adhesion of scale during a scarfing process is present on a slab. In this case, the actual surface flaws are mixed in the scale and the stripe pattern, and the difference in luminance between the actual surface flaw detected as a dark part and the surrounding area becomes small, so that the surface flaw cannot be detected. In addition, even if flaws do not actually exist in the scales and stripes, they are erroneously recognized as point-like flaws and linear flaws because dark portions exist in points and lines at these scales and stripes. Is detected. The grinding device also grinds such a misidentified portion, reducing the weight of the finally obtained slab and reducing the yield of the slab. Further, since the grinding amount is increased more than necessary, there is a problem that a required number of steel slabs (slabs and the like) cannot be processed within a predetermined time using a grinding device. The present invention has been made in view of such circumstances, and by accurately and efficiently discriminating the type and position of surface flaws on a billet, the amount of care required for the billet can be reduced, and the billet can be used as a product. It is an object of the present invention to provide a method for treating a surface defect of a steel slab which can improve the yield at the time of finishing and can further increase the number of processed steel slabs per fixed time of a grinding device.

[0004]

According to the present invention, there is provided a semiconductor device comprising:
The method for treating a surface flaw of a slab described above includes marking the slab using a sign symbol designating a flaw type of the surface flaw and its position, and then capturing the slab with an imaging device and including an imaging position. Image data is acquired, and surface flaw data including the flaw type and the position of the mark is extracted from the image data. The type of surface flaw is, for example, a vertical crack, a horizontal crack, a crack, an edge crack,
And defects such as pinholes. The sign symbol is a group of identification symbols defined for each type of the surface flaw. When assigning these identification symbols to the steel slab, drawing using paint, chalk, etc., directly around the surface flaw or the position of the surface flaw on the steel slab determined by the inspector or the surface flaw detection device. Alternatively, a sticker having a predetermined shape printed in advance may be attached. Furthermore, the identification symbol group is described with oil paint such as carbon or black on the surface of the sheet-shaped magnet (magic seal) or the surface of the magic seal formed by sticking a flake that totally reflects light such as stainless steel or aluminum foil. Then, these magic seals or the like may be attached to necessary portions on the surface of the steel piece. The imaging device refers to a device such as a film-mounted camera, a television camera, and a digital camera that can scan the surface of a billet and record an image for each field of view as image data.

[0005] A method for treating a surface flaw of a billet according to claim 2 is as follows.
In the method for treating a surface flaw of a steel slab according to claim 1, a correspondence table for designating a degree of processing of the steel slab for each flaw type of the sign symbol is set in advance, and the surface flaw data and the correspondence table are set. Based on the information, the position of the sign is cleaned. The degree of maintenance processing refers to a processing instruction item that specifies the type of maintenance processing such as grinder grinding and gas heat melting processing, whether or not it is necessary, the degree of maintenance processing, and the like.

[0006] A method for treating a surface flaw of a billet according to claim 3 is as follows.
The method for treating surface flaws on a billet according to claim 1 or 2,
The sign consists of a combination of a vertical line along the casting direction of the slab and a horizontal line perpendicular to the vertical line.
The method for treating surface flaws on a billet according to claim 4 is described in claims 1 to 3.
In the method for treating surface flaws on a steel slab according to any one of the above, the steel slab is a polished steel slab obtained by removing a surface layer portion such as an oxide layer.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIGS. 1 (a), (b), (c)
Inspection process, an image recording step in the surface flaws treatment method of steel pieces according to the first embodiment of the present invention, respectively, illustrating the cleaning process, FIG. 2 (a), (b) each flaw type k ₁ , and illustrates an example of the arrangement of beacon symbols corresponding to the defect type k _2, illustrates an example of the arrangement of FIG. 3 (a), (b) each flaw type k _3, and labeling symbol corresponding to the flaw type k ₄ , FIG.
FIG. 4 is an explanatory view of a surface flaw treating apparatus to which a method for treating surface flaws on a billet according to a second embodiment of the present invention is applied.

Hereinafter, a method for treating a surface flaw of a billet according to a first embodiment of the present invention will be described. As shown in FIG. 1, the method for treating a surface flaw of a slab
Inspection step (a) of inspecting the surface flaw of No. 0 to mark the steel slab 10 with the sign symbol 11 and photographing the marked steel slab 10 using a television camera 12 which is an example of an imaging device. An image recording step (b) of recording the image data in the control device 13;
And a maintenance processing step (c) of performing the maintenance processing of the billet 10 by driving the maintenance processing device 14 and performing the maintenance processing. Hereinafter, each process (a)-of the said surface flaw treatment method
(C) will be described in more detail.

In the inspection step shown in FIG. 1A, a length of 5500 mm, a width of 1000 mm,
The steel slab 10 having a thickness of 250 mm is placed on the mounting member 15 and the steel slab 10 is inspected. Here, the steel slab 10 is obtained by removing the surface layer by fusing with a gas burner or the like, and then removing the surface-adhered oxide layer after the fusing by polishing with a brush or the like. At the time of surface flaw inspection, the surface flaws are classified into n flaw types based on past steel slab inspection results. Next, a correspondence table between the flaw type k and the sign symbol 11 is created in advance as shown in Table 1. Then, the inspector uses a surface flaw detection device (not shown) or inspects the presence or absence of the surface flaw of the steel slab 10 by inspection, and when the surface flaw is detected, the flaw type is compared with the correspondence table, A corresponding marker 11 is used to mark a detection point on the billet 10.

[0010]

[Table 1]

In this marking, a sign symbol 11 is applied to a portion having a surface flaw using a paint, a seal, a chalk, a magic seal, or the like, desirably having a color tone different from that of the billet, for example, yellow, white, or red. Mark. In particular, when the magic seal having a high light reflectance is used, the recognition rate of the type of the sign is improved, and the magic seal can be easily attached and can be reused, which is preferable. Vertical line (refers to the line segment along the billet casting direction) and horizontal line (refers to the line segment perpendicular to the vertical line)
2 and FIG. 3, assuming that a specific type of surface flaw k exists in the hatched portion indicated by each of the sign symbols 11. Defined. Since the sign symbol 11 is configured by combining vertical and horizontal line segments in this manner, detection of the sign symbol 11 and calculation of image data in subsequent image processing are easy, and there is an advantage that misidentification can be eliminated. . Beacon symbol 11 shown in FIG. 2 (a), for example, grinding is an identification symbol indicating that a minor surface flaws k ₁ is not necessary, in the care processes after, that processing of the hatched portion is omitted Is shown. 2 (b) and FIG.
3 (a) and 3 (b) indicate surface flaws k ₂ (cracked), k ₃ (pinhole), and k ₄ (vertical,
This is an identification symbol corresponding to (lateral cracking). Here, the crack means a set of small cracks extending in an unspecified direction. The pinhole is a point-like defect made of irregularities or deposits, and the vertical crack and the horizontal crack are cracks in the length direction and the width direction of the slab, respectively.

In the image recording step shown in FIG. 1B, the television camera 12 is moved along the surface of the placed billet 10.
Is moved to photograph the steel slab 10, and image data over the entire length is input to the control device 13. At the time of this photographing, a position detection sensor (not shown) is attached to the television camera 12 to acquire position data including an image pickup position, and position data corresponding to the image data is added to make the position of the sign 11 more accurate. Can also be grasped. The control device 13 analyzes the image data and the position data, calculates the type and position of the sign symbol 11 on the image data, and calculates the position of the sign symbol as shown in Table 2 (average of the sign symbol 11). Position flaw data k, flaw type k, and surface flaw data of a billet consisting of the area S of the portion indicated by the sign 11 can be obtained.

[0013]

[Table 2]

The positions X and Y of the sign 11 are the billet 1
With one of the four corners of 0 as a reference point (0, 0), position coordinates are set with the length and width directions as X and Y axes, respectively.
The X-axis and Y-axis values are displayed. At this time,
Since the sign 11 is composed of a combination of vertical and horizontal lines that are orthogonal to each other, the sign 11 can be extracted from the image data by simple image processing, and high-speed processing can be performed. That is, a set of pixels (x, y) constituting a vertical line and a horizontal line is a series of pixel groups (x _k ,
y ₁ ), (x _k , y ₂ ), (x _k , y ₃ )..., etc. The algorithm can be simplified, and the recognition rate of the sign 11 can be improved. Also,
Usually, a striped pattern, streak-like unevenness or the like extending in the length direction is present on the billet, which may be an obstacle in reading the sign symbol 11, but may be an obstruction when reading the sign symbol 11. Therefore, it is possible to improve the recognition rate of the sign 11 even for such a disturbance.

In the maintenance processing step shown in FIG. 1C, the flaw type k in the surface flaw data recorded for each billet 10 is represented by the correspondence between the flaw type k and the degree of maintenance M as shown in Table 1. As compared with the table, the controller 13 can be used to determine any one of the _j maintenance degrees M _{1 to} M _j set for each of the _n flaw types k _{1 to} k _n . For example, if a flaw type of the first steel plate, as shown in Table 3 is k _1, when cleaning the working ratio is M ₁ (maintenance free), and the defect type of the second steel plate is k ₂ is The maintenance degree is set to M ₂ (grinding to a predetermined thickness) or the like.

[0016]

[Table 3]

Then, based on the surface flaw data to which the degree of maintenance M is added, the maintenance processing device 14 is driven, so that only the necessary portions of the billet 10 can be efficiently processed. Thereby, it is possible to mechanically perform the care treatment while avoiding excessive grinding of the steel slab 10 as in the related art, and to efficiently process the steel slab 10.

Next, a description will be given of a method for treating surface flaws on a billet according to a second embodiment of the present invention. As shown in FIG. 4, the surface flaw processing equipment 20 includes a CCD camera 23 for continuously photographing the surface of the billet 21, a position sensor 24 for detecting the photographing position, and image data from the CCD camera 23. And a grinding device 26 for the steel slab 21 whose grinding position, grinding amount and the like are controlled by the computer 25. Surface flaw treatment equipment 2
In the method for treating surface flaws on a slab, the pretreatment is performed on the slab 21 after continuous casting by using a polishing device (not shown) that rotates a metal brush roll or the like, so that the scale adheres to the surface. Etc. are removed. As a result, the work of identifying the surface flaw portion can be facilitated, and the effect of recognizing the mark 22 to be marked can be increased. Next, the polished steel piece 21
Is inspected by an inspector in accordance with an inspection guideline set in advance, and a sign 22 composed of a vertical line and a horizontal line set for each type of surface flaw is detected on the steel piece 21. Mark the corresponding point of the flaw. Next, the steel slab 21 with the sign 22 is transferred to the surface flaw treatment equipment 20.
At a predetermined transfer speed, the steel piece 21 is photographed by the CCD camera 23, and this image data is
5 to obtain the flaw type k of the sign 22 and its position (X, Y). Then, using the surface flaw data composed of the flaw type k of the marker symbol 22 and its position (X, Y), a maintenance degree M corresponding to a predetermined flaw type k is determined, and these surface flaw portions are ground. When the position of the apparatus 26 is reached, the grinding apparatus 26 can be operated based on the degree of the above-mentioned care processing to continuously perform the desired grinding processing.

The embodiments of the present invention have been described above.
The present invention is not limited to these embodiments, and all changes in conditions without departing from the gist are within the scope of the present invention. For example, in the present embodiment, the corresponding sign symbols are set as the flaw types k of the surface flaws are only four types, but these settings are not fixed.
The combination method can be changed according to the form of the surface flaw and the type of procedure to be processed in the following, or the flaw type of the surface flaw can be added.

[0020]

In the method for treating the surface flaw of a steel slab according to claims 1 to 4, since the marking of the steel slab is performed using a sign symbol designating the position of the surface flaw and the type of the surface flaw, it is distinguished sharply. The flaw type and position of the surface flaw can be clearly grasped. Then, the billet is photographed by the imaging device to obtain image data including the imaging position, and the flaw type of the sign symbol and the surface flaw data including the position are extracted from the image data, so that the sign symbol misrecognition rate is low. And highly accurate surface flaw data can be obtained. Therefore, based on the surface flaw data, an efficient care treatment can be performed, and the production yield when rolling a steel slab to obtain a product can be improved.

In particular, in the method for treating the surface flaw of a billet according to the present invention, a correspondence table for designating the degree of care processing of the billet for each flaw type of the sign symbol is set in advance, and the surface flaw data and the corresponding correspondence are set. Since the care processing of the positions of the sign symbols is performed based on the table, the care processing of the billet can be performed accurately and efficiently. In the method for treating surface flaws on a slab according to the third aspect, the sign symbol is a symbol obtained by combining a vertical line along the casting direction of the slab and a horizontal line perpendicular to the vertical line. In the process, the identification process of the sign symbol can be performed extremely easily, the marking work by the inspector has little variation, and the marking work can be easily performed. In the method for treating a surface flaw of a steel slab according to claim 4, since the steel slab is a polished steel slab obtained by peeling a surface layer portion such as an oxide layer, the type of the surface flaw and the position of the surface flaw are determined. Detection can be facilitated, and generation of defects during the subsequent rolling process can be suppressed.

[Brief description of the drawings]

FIGS. 1 (a), 1 (b), and 1 (c) are explanatory views of an inspection step, an image recording step, and a care processing step in a method for treating a surface slab of a billet according to a first embodiment of the present invention. is there.

FIGS. 2A and 2B are diagrams showing examples of arrangement of marker symbols corresponding to flaw types k ₁ and k ₂ , respectively.

FIGS. 3A and 3B are diagrams showing examples of arrangement of marker symbols corresponding to flaw types k ₃ and k ₄ , respectively.

FIG. 4 is an explanatory diagram of a surface flaw treatment facility to which a method for treating surface flaws on a billet according to a second embodiment of the present invention is applied.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 billet 11 sign symbol 12 television camera (image pickup device) 13 control device 14 care processing device 15 mounting member 20 surface flaw treatment equipment 21 billet 22 sign symbol 23 CCD camera 24 position sensor 25 computer 26 grinding device

Continued on the front page (72) Munehiro Tsuchida 1-1, Tobata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Prefecture Inside Nippon Steel Corporation Yawata Works (72) Inventor Tomohiro Furuta 1, Tobihata-cho, Tobata-ku, Kitakyushu, Fukuoka Prefecture No. 1 New Nippon Steel Corporation Yawata Works

Claims (4)

[Claims] 1. After marking a billet using a mark symbol designating a flaw type and a position of a surface flaw, the billet is photographed by an imaging device to obtain image data including a photographing position, A method for treating the surface flaw of a billet, wherein surface flaw data comprising the flaw type of the sign symbol and its position is extracted from the image data. 2. A correspondence table designating the degree of maintenance of the billet for each type of flaw of the sign is set in advance, and the position of the sign is maintained based on the surface flaw data and the correspondence table. The method according to claim 1, wherein the treatment is performed. 3. The steel according to claim 1, wherein the sign comprises a combination of a vertical line along a casting direction of the slab and a horizontal line perpendicular to the vertical line. Surface flaw treatment method for pieces. 4. The steel slab according to claim 1, wherein the steel slab is a polished steel slab obtained by removing a surface layer such as an oxide layer. Surface flaw treatment method.