JP2001108635A - Apparatus for correcting transverse oscillation of billet at magnetic particle testing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for correcting transverse oscillation of billets of a magnetic particle testing apparatus which can specify a correct flaw position. SOLUTION: Two laser distance sensors 15A and 15B are set opposite to A and B planes with projection axes kept parallel to plane cameras 9A and 9B respectively. A shift-measuring means for detecting a distance between an angular billet 1 and the A, B plane and a coordinates-converting means are set in relation to a control system. The coordinates-converting means calculates a shift of the angular billet 1 when a distance signal is introduced from the shift-measuring means, and converts coordinates of an edge part corresponding to an upper corner of the angular billet 1 obtained on an image taken by an image pre-processing device 13 based on the calculation image, thereby correcting a flaw position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic particle flaw detector for detecting flaws on a surface of a square billet. More specifically, the present invention relates to a billet capable of accurately detecting the position of a surface flaw portion when the square billet traverses in the width direction. The present invention relates to a lateral shake correction device.

[0002]

2. Description of the Related Art When detecting surface flaws of a square billet using a magnetic particle flaw detector, it is not possible to avoid occurrence of lateral deflection, that is, lateral deflection, during the horizontal transport of the square billet. Cannot be fixed in a straight line, the edge of the angular billet image captured by the imaging device cannot be fixed. Therefore, it is necessary to correct and specify the flaw position based on the edge to detect surface flaws. This is an indispensable means.

In the prior art, as shown in FIG. 6, an edge detecting light source 32 irradiates an edge 1E of a square billet 1 with a light source, and a reflected light of the edge 1E is reflected by an imaging device 31 such as an industrial television camera. There is one that detects an edge portion 1E by imaging (for example, Japanese Patent Publication No. 58-47015).
Reference). Further, as another conventional technique, as shown in FIG. 7, the magnetic particle flaw detection device 33 is supported by a follow-up device 34 in order to minimize the vibration (lateral vibration) between the magnetic particle flaw detection device and the angular billet 1. Some have been made. The tracking device 34 includes, as constituent members, an eddy current sensor 35 that detects a gap between the angular billet 1 and a fluid pressure cylinder 36 that supports the magnetic particle flaw detection device 33 so that the position thereof can be adjusted. The fluid pressure cylinder 36 keeps a fixed distance between the angle billet 35 and the square billet 1 so that the imaging apparatus can capture an image while always keeping a fixed distance with respect to the square billet 1.

[0004]

In the former prior art shown in FIG. 6, an edge detecting light source 32 is provided from below the angular billet 1.
Is irradiated on the edge portion 1E to enhance the brightness of the edge portion 1E, thereby detecting the edge portion 1E on the image.
Is not suitable as a magnetic particle flaw detector due to the poor surrounding environment below the square billet 1 and inconvenience in terms of maintenance management.

On the other hand, in the case of the latter equipped with the follow-up device 34, there is no problem in terms of performance and it is suitable for a magnetic particle flaw detection device, but it is difficult to take a large cost as a device, and it is not popular. Is the problem.

[0006] The present invention has been made to solve such problems, and an object of the present invention is to provide:
By combining a laser distance sensor with a simple structure and a control system with a simple circuit design, a high-accuracy flaw position detection function can be achieved, so that inexpensive equipment can be used to accurately identify flaw positions. It is an object of the present invention to provide a billet lateral vibration correcting device in a magnetic particle flaw detector.

[0007]

The present invention has the following configuration to achieve the above object. In other words, the invention of claim 1 according to the present invention is characterized in that a fluorescent magnetic powder is magnetically attached to a surface flaw portion to form a fluorescent magnetic powder pattern, and the two horizontal upper billets in horizontal conveyance are provided. The fluorescent magnetic powder pattern is formed by an imaging device including two flat cameras provided so as to face each other and an upper corner camera provided so as to face an upper corner which is a boundary between upper corners of the upper edges of the two planes. After detecting a surface flaw of the square billet by a control system including a surface flaw detection device including an image pre-processing device and a general control device, marking was performed on the surface flaw portion. In the magnetic particle flaw detector, the two flat cameras are provided with two laser distance sensors installed so as to be respectively opposed to the two planes so that the light projecting axes are parallel to each other. A displacement measuring means for detecting a distance from the plane of the square billet, and calculating a displacement of the angular billet with reference to a horizontal conveyance center line by introducing a distance signal from the displacement measuring means, and calculating the displacement of the image billet based on the calculation result. Coordinate conversion means for correcting the position of the flaw by converting the coordinates of the edge corresponding to the upper corner of the angular billet obtained on the image captured by the processing device, in relation to the control system. A billet lateral shake correcting device in a magnetic particle flaw detection device, characterized in that:

The invention according to claim 2 according to the present invention is characterized in that, in a preceding step, a square billet during horizontal conveyance in which a fluorescent magnetic powder pattern is formed by magnetically attaching fluorescent magnetic powder to a surface flaw portion, An A-plane camera and a B-plane camera provided opposite to the upper A-plane and the B-plane adjacent to the square billet, respectively;
A which is a boundary between upper corners A and B of upper edges of planes A and B
An AB corner camera provided to face the B corner, a DA corner camera provided to face the A horizontal corner surface on the lower edge of the A plane, and a DA corner camera provided to face the B horizontal corner surface of the lower edge of the B plane. A first control system configured to include a first surface flaw detection device including a first image pre-processing device and a first general control device by capturing the fluorescent magnetic powder pattern with a first imaging device including a BC corner camera. By detecting the surface flaws of the square billet, in the subsequent step, immediately after passing through the preceding step, by rotating 180 ° around the longitudinal axis, the adjacent upper and lower C-plane and the D-plane of the square billet are respectively inverted. A second imaging device including a C-plane camera and a D-plane camera provided to face each other, and a CD corner camera provided to face a CD corner serving as a boundary between upper and lower corners of the C and D planes. Fluorescent magnetic powder pattern Imaging, detecting a surface flaw of the angular billet by a second control system including a second surface flaw detection device including a second image pre-processing device and a second general control device, and thereafter detecting the surface flaw A magnetic particle flaw detection device for marking a portion, comprising two laser distance sensors installed so as to be parallel to the A and B plane cameras, respectively, and to be opposed to the A and B planes, respectively. Displacement measuring means for detecting the distance between the square billet and the opposing planes A and B, and the displacement of the square billet with respect to the horizontal transport center line is calculated by introducing a distance signal from the displacement measuring means. Correction of a flaw position by converting coordinates of each edge corresponding to an AB corner, a BC corner and a DA corner of a square billet obtained on an image captured by the first image preprocessing device based on the result And a coordinate conversion means for performing the above operations are provided in relation to the first control system, and the light projecting axes are respectively set in parallel with the C and D plane cameras so as to face the C and D planes. A displacement measuring means comprising two laser distance sensors for detecting the distance between the square billet and the opposing C and D planes; and introducing the distance signal from the displacement measuring means to a position with respect to the horizontal transport center line. The displacement of the angular billet is calculated, and based on the calculation result, the CD corner, the BC corner, and the D corner of the angular billet obtained on the image captured by the second image preprocessing device.
A coordinate conversion means for correcting the position of the flaw by converting the coordinates of each edge portion corresponding to the A corner;
A billet lateral shake correction device in a magnetic particle flaw detection device, which is provided in connection with a control system.

According to a third aspect of the present invention, there is provided the billet lateral deflection correcting device in the magnetic particle flaw detector according to the first or second aspect, wherein the coordinate conversion means converts the coordinates of the edge portion. Calculate the sum Z of the displacement vectors obtained from the distance signals of the two laser distance sensors installed opposite to the two planes adjacent to each other on both sides of the edge, and calculate the sum Z of the vector sum Z on the horizontal axis. It is characterized by being obtained by obtaining the projection X.

According to a fourth aspect of the present invention, there is provided a magnetic particle inspection apparatus according to the third aspect, wherein the billet lateral deflection correcting device includes a surface flaw detecting device and a general control device. The system divides the angular billet sequentially and horizontally conveyed into a predetermined number of unit blocks, collects the image captured by the image preprocessing device into blocks corresponding to the unit blocks, collects flaw data for each block, and generates a billet. At the time of flaw detection, the distance signals of the two laser distance sensors are read at regular time intervals, and the average displacement is obtained from the distance signals of the two laser distance sensors within the block for each block,
It is characterized in that a flaw position in a block is corrected for each block.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

FIG. 1 is a line configuration diagram of a magnetic particle flaw detection apparatus according to an embodiment of the present invention, and FIG. 2 is a control system configuration diagram of the magnetic particle flaw detection apparatus. FIG. 3 shows a layout diagram of a camera and a distance sensor in a previous process of the magnetic particle flaw detector, and FIG. 3B shows a layout diagram of a camera and a distance sensor in a subsequent process.

Referring to FIG. 1, reference numeral 1 denotes a square billet;
For example, the side length is one hundred and several tens mm, and the length in the longitudinal axis direction is 8 to 13.
m, which is made of a square pillar-shaped piece of steel, passes through a shot blast (not shown), and after the fluorescent magnetic powder solution is sprayed on the surface, the magnetic magnetic powder adheres to the surface flaws due to the magnetization of the billet main body and the fluorescent light is applied. The square billet 1 on which the magnetic powder pattern is formed is composed of four planes A, B, C, and D, which are adjacent to each other.
A drum-shaped transport roller 2 (see FIG. 3) and a pinch roller (not shown) are arranged so that the plane faces obliquely upward and upward.
It is transported horizontally at a speed of about several m / min to 30 m / min in the direction of the arrow. The A-plane, B-plane, upper (AB) corner, and both lateral (DA, BC) corners of the angular billet 1 are inspected for flaws in the pre-process E including the pinch roller 3. Thereafter, the square billet 1 is rotated around the longitudinal axis by 180 ° by the reversing machine F to be reversed, and a post-process G including the pinch roller 3 is provided.
At C plane, D plane, upper (CD) corner and both sides (D
A, BC) Inspect corners.

The corner billet 1 thus inspected for flaws
In the post-processing step H, after further internal flaw detection, the pre-processing step E
In the marking step I, marking is performed on the surface flaws based on the flaw detection results obtained in the following step G. It is known that the surface flaw in this case includes a linear flaw (a crack flaw substantially parallel to the longitudinal direction) and an irregular flaw (mainly a scab-like splinter flaw).

Referring to FIG. 1 to FIG. 3 in such a magnetic particle flaw detection apparatus, in a pre-process E, a first camera constituted by disposing five cameras such as an industrial television camera around the square billet 1 is provided. An imaging device, a displacement measuring unit configured by arranging two laser distance sensors close to the camera, and a first system that processes output signals from the first imaging device and the displacement measuring unit to control system of flaw detection. A control system 5 is provided,
In post-process G, the camera is also moved around
A second imaging device configured by arranging two laser distance sensors close to the camera; a displacement measurement unit configured by arranging two laser distance sensors in close proximity to the camera; and a processor configured to process output signals from the second imaging device and the displacement measurement unit. And a second control system 6 for controlling the flaw detection system. In FIG. 2, reference numeral 4 denotes a process computer for comprehensive management for exchanging information with the first and second control systems 5 and 6, 7 a monitor such as a CRT, 8 a marking control device, and 10 a square billet. 1 shows an ultraviolet light source for irradiating the surface of No. 1 respectively.

The first imaging device in the pre-process E is a square billet 1
An A-plane camera 9A which is opposed to the A-plane at a fixed distance above the A-plane at a fixed distance, and whose light-receiving axis is aligned with a vertical line passing through the longitudinal center line of the billet 1 in the front-rear direction and orthogonal to the A-plane.
And the same as above with the B plane at a certain distance,
A B-plane camera 9B fixed with its light receiving axis aligned with a vertical line passing through the longitudinal center line of the billet 1 in the front-rear direction and orthogonal to the B plane, and the upper and lower edges of the A and B planes on the A and B corner surfaces. An AB corner camera 9AB fixed to the AB corner, which is a boundary, at a certain distance above and with the light receiving axis aligned with a vertical line passing through the AB corner, and a boundary between the A, D horizontal corner planes of the A, D plane. And a DA corner camera 9DA having a light receiving axis fixed to the DA corner at right angles to the DA corner, and a B, C plane B, C plane.
The camera is provided with five cameras including a BC corner camera 9BC which is opposed to a BC corner which is a boundary of a horizontal corner surface at a predetermined horizontal distance horizontally, and which has a light receiving axis perpendicular to the BC corner. The video signals of the four cameras excluding the BC corner camera 9BC among the five cameras are transmitted to the first image preprocessing device 13 of the first surface flaw detection device 12 in the first control system 5. In this case, the A-plane cameras 9A and B
The flat camera 9B, the DA corner camera 9DA, and the BC corner camera 9BC are preferably provided at respective symmetrical positions with respect to the horizontal transport center line (a reference line for transport) of the square billet 1 in the preceding step E. .

In the present specification, the surface covered by the flat camera is referred to as a "plane", and the flaw-detected data is referred to as a "plane (plane)" in order to facilitate understanding of the relationship between the camera and the surface of the square billet. Flaw detection) data ”. The area covered by the corner camera is called “corner”, and the detected data is called “corner (flaw detection) data”. (The same applies to the upper and horizontal corners.)
Divide the "corner" into two at the boundary, and each "corner (side)"
Surface ". A combination of the "plane", "upper corner surface", and "lateral corner surface" is referred to as a "combined surface", and the detected data is also referred to as "combined surface data".

The displacement measuring means in the preceding step E is arranged at a position close to the A-plane camera 9A, preferably at a position immediately before the A-plane camera 9A, to face the A-plane of the angular billet 1 at a predetermined distance above, and At the position close to the B-plane camera 9B, preferably at the position immediately before the B-plane camera 9B, a square billet is provided at a position close to the B-plane camera 9B, preferably at a position close to the B-plane camera 9B. And a laser distance sensor 15B for the B plane fixed so that the light projecting axis is parallel to the light receiving axis of the B plane camera 9B. The distance signals 15A and 15B are transmitted to the first general control device 11 in the first control system 5. In this case, it is preferable that the laser distance sensor 15A and the laser distance sensor 15B are respectively provided at symmetrical positions with respect to the horizontal transport center line.

The second image pickup device in the post-process G is a square billet 1
C-plane camera 9C which is opposed to the C-plane at a predetermined distance above the C-plane, and whose light-receiving axis is aligned with a vertical line passing through the longitudinal center line of the billet 1 in the front-rear direction and orthogonal to the C-plane.
And the same as above with a certain distance above the D plane,
A D-plane camera 9D fixed with its light-receiving axis aligned with a vertical line passing through the longitudinal center line of the billet 1 in the front-rear direction and orthogonal to the D-plane, and a C- and D-top corner surface at an upper edge of the C- and D-planes; The camera is provided with three cameras: a CD corner camera 9CD, which is opposed to a CD corner serving as a boundary at a certain distance above and fixed by aligning a light receiving axis with a vertical line passing through the CD corner. The video signal of the camera and the video signal of the BC corner camera 9BC in the pre-process E are transmitted to the second image preprocessing device 13 of the second surface flaw detection device 12 in the second control system 6. In this case, C-plane cameras 9C and D
It is preferable that the flat cameras 9D are provided at symmetrical positions with respect to the horizontal transport center line of the square billet 1 in the post-process G. Meanwhile, CD corner camera 9CD
Is preferably provided at a position jointly related to the AB corner camera 9AB with respect to the horizontal transport center line.

The displacement measuring means in the post-process G is arranged at a position close to the C-plane camera 9C, preferably at a position immediately before the C-plane camera 9C, so as to face the C-plane of the angular billet 1 with a certain distance above, At the position close to the C-plane camera 9D and preferably at the position close to the D-plane camera 9D, preferably at the position immediately before the D-plane camera 9D, the angular billet is fixed at a position where the projection axis is fixed in parallel with the light receiving axis of the C-plane camera 9C. A laser distance sensor 15D for the D plane, which is fixed to the D plane 1 at a predetermined distance above and parallel to the light receiving axis of the D plane camera 9D. The distance signals 15C and 15D are transmitted to the second general control device 11 in the second control system 6. In this case, the laser distance sensor 15C and the laser distance sensor 15D
Is preferably provided at a position symmetrical with respect to the horizontal transport center line.

The first and second surface flaw detection devices 12 have the same structure and will be described together. In the image preprocessing device 13 corresponding to eight cameras, each of which is a set of four, the image capturing, shading-luminance unevenness correction, filtering, labeling / feature amount are provided for each image capturing processing board. Each process of extraction is performed in real time.

Since the linear flaw has a component parallel to the longitudinal direction of the billet, it is considered that the linear flaw can be detected by taking a difference in the width direction of the billet. On the other hand, the irregular shaped flaw is a flaw having a component parallel to the width direction in addition to the longitudinal direction, so that it is necessary to take a difference in the longitudinal direction of the billet. The label obtained by the difference contains noise having a very small area of, for example, about 1 mm ² , which causes erroneous detection. Although detailed description is omitted here, noise can be reduced by extracting a label having an area smaller than 1 mm ² and removing the label.

As described above, the image preprocessing device 13 requires a filtering process. Therefore, three image capture processing boards are required for each of the eight cameras that capture each surface, and the processing is performed in parallel.

Image pre-processing device 1 for performing such pre-processing
The surface flaw detection device 12 provided with the image 3 performs image capturing, shading-luminance unevenness correction, filtering, and labeling, and obtains a label that is considered to be a flaw and a label that is considered to be point-like noise among the obtained labels. After a certain period of time, the label is transferred and the measurement of the next block is started at the same time (“filtering process” and “label transfer” in the uppermost stream on the left end side in FIG. 4). Step).

The first and second general control units 11 which perform so-called general control for causing the image pre-processing unit 13 to perform processing such as image capture and transfer of the processing result, transmit information from the process computer 4. The flaw detection operation control in the pre-process E and the post-process G is performed based on. In other words, the billet insertion is started, the billet leading end is detected, the flaw detection is started, the block is switched, and the billet trailing end is detected in this order. After the flaw detection is completed, a label table (list) is created. In this case, the position of the received label is coordinate-converted in units of mm, a label table is created, and the correction of the speed change, the correction of the length of the flaw, and the correction of the lateral shake (described in detail later) are performed.
Next, based on the coordinates of the label received from the image preprocessing device 13, the flaws at close distances are integrated into one large flaw, and the flaws are arranged and integrated.

Subsequently, surface synthesis is performed based on the preprocessing results of the pre-process E and the post-process G. For example, DA corner, A side,
The preprocessing results of each camera in the AB corner are combined to combine the flaw information of the entire A surface. Next, while detecting flaws from the surface synthesis result, the type classification and rank determination of each flaw are performed, the flaws of each synthesized surface are rearranged in the longitudinal start position order, the number of flaws per surface, the flaw length are obtained. Flaw information is created, marking is performed in accordance with the processing specifications of the marking step I based on the flaw information, and the flaw detection result for each billet is transmitted to the process computer 4.

FIG. 4 shows a flow of image processing in the first and second general control devices 11. In FIG. 4, after the filtering process, a process is performed on the transferred label, and a comparison between the normal label and the corrected label is performed.
Eliminates point noise and performs flaw arrangement / integration processing.

Hereinafter, an outline of the image processing will be described for each flow order with reference to FIG. (21) Label sorting: Label sorting for storing labels in a table for each required process. (22) Speed correction: Speed correction is performed for each sub-block. In this case, the sub-block length, the speed correction rate, and the number of correction lines up to the head of the sub-block are calculated and stored in an array. (23) Boundary label sorting: Among the label data after speed correction, those that are in contact with the block boundaries are additionally stored in the boundary label table. (24) Merge boundary labels: Y at the starting point
A label whose (relative) coordinate is 0 is set as a head label, and a label whose Y (relative) coordinate of the end point is the number of block lines (after correction) is set as a tail label. (25) Label table integration: Add the label of the boundary label table to the speed correction label table. (26) Re-detection of flaws / re-detection of noise: Calculate the area of the labels in the speed correction label table, and separate the labels above the threshold value (area, diameter) from the labels within the threshold value range, and Add to each image capture processing board. (27) Table integration / sorting: If there is data with the same block number, they are put together. The labels are sorted by starting point Y and starting point X. (28) Removal of point noise: The point label is extracted by comparing the flaw label extracted by the flaw redetection / noise redetection in step (26) with the point noise label to remove the point noise. (29) Coordinate transformation: coordinate transformation means (coordinate transformation device) as a component that characterizes the present invention
In the coordinate conversion algorithm according to the present invention, it is unavoidable that the billet undergoes side-to-side vibration during transport. Therefore, considering the positional relationship with a camera that photographs in a fixed state, label coordinates (the image preprocessing device 13) It is absolutely necessary to correct in the width direction (coordinates on the image captured by). Although a specific mode of billet lateral shake correction will be described later, correction for each plane and each corner is performed. (30) Flaw arrangement / integration: Based on the coordinates of the label received from the image preprocessing device 13, the flaws at close distances are integrated into one large flaw. Then, based on the preprocessing results of the pre-process E and the post-process G, the surface synthesis is performed.

FIGS. 5A and 5B are explanatory diagrams for setting the width position of the flat camera based on the layout shown in FIG. 3, FIG. 5B is a diagram for explaining the width position setting of the corner camera, and FIG. An explanatory diagram of the width position setting near the corner edge of the corner camera is shown in FIG. With reference to FIG. 5 and FIG. 3 (a), the mode of billet lateral shake correction (correction of label coordinates in the width direction) in the preceding process E will be described below. The description of the post-process G is omitted because it has the same contents. It should be noted that there is no need to correct the longitudinal position setting. Therefore, the control unit switches the block to the image preprocessing device for each prescribed pulse, and records the head position of each block. Things.

(3) Position setting of the flat camera in the width direction (FIG. 3)
(A) and FIG. 5 (a)]: A flat camera (for example, a camera using a charge-coupled device CCD as an element member) is moved downward from the upper corner position (point 0) of the flat camera in parallel to the A plane of the billet 1. Set the X coordinate in the direction. The coordinates at the top and bottom of the flaw width position are obtained by converting the distance to the corner position (set value) on the flat camera into mm. That is, (label coordinates−corner position on flat camera) × view field width (mm) per image element of camera. This is the same for the B plane.

(4) Position setting of the corner camera in the width direction: (A) Setting of the width position [FIG. 3 (A) and FIG. 5 (B)] An upper corner camera will be described as an example. The coordinates are divided into two on the left and right sides of the corner position (set value) of the corner camera, and each is converted into the coordinates of the flat camera. That is, FIG.
In this case, [corner position on flat camera + (label coordinate−corner camera corner position) × √2] × view width (mm) per image element of camera. Similarly, the horizontal corner camera performs the coordinate conversion, but converts the coordinates of the upper corner of each plane to zero. (B) Setting of the width position near the corner edge [FIGS. 3 (A) and 5 (C)] It is assumed that the edge vicinity is rounded and the radius R is rounded, and the flat camera near the edge detected by the corner camera is determined. Is projected as shown in FIG. Therefore, the projection a ′ of the origin a of the corner camera onto the flat camera is a ′ = R−
(R / √2) The projection b ′ of the position b of the corner camera R / √2 onto the plane camera is b ′ = R. Thus, the projection x ′ of the position of the corner camera x on the plane camera is x '= √2 · x + R− (R / √2), and the position is set based on so-called vector calculation.

The above-mentioned correction of the lateral vibration of the billet is performed after obtaining the position of the flaw width converted into the coordinates of the plane camera. Specifically, the correction is performed as follows. Laser distance sensors 15A and 15B are installed so as to face the plane A and plane B of the square billet 1, respectively, and the image taken in by the image preprocessing device 13 is divided into blocks to collect flaw data. At this time, the values of the laser distance sensors 15A and 15B are read at predetermined time intervals during billet flaw detection. After calculating the average displacement of the laser distance sensors 15A and 15B in each block, the position of the flaw in the block is corrected for each block.

In this case, the flaw position correction on the A plane is performed by performing coordinate conversion based on the amount of movement of the laser distance sensor 15B facing the B plane. The coordinate conversion is performed based on the amount of movement of the laser distance sensor 15A facing the plane. On the other hand, AB
The correction of the flaw position near the corner is performed by the laser distance sensor 15B.
And the sum Z of the movement amount vectors of the laser distance sensor 15A.
Is calculated, and then the coordinates of the corner camera, that is, the projection on the horizontal X-axis are obtained to perform the coordinate conversion. The flaw position correction for the C plane and the D plane is the same as that for the A plane and the B plane, and the flaw position correction for the BC corner, the DA corner, and the CD corner is A
Same as for the B corner.

[0034]

The present invention is embodied in the form described above and has the following effects. That is, according to the present invention, the position correction of the surface flaw portion with respect to the lateral runout in the width direction of the square billet can be reliably performed with a simple configuration in which a pair of laser distance sensors is installed above the conveyance path of the square billet. The flaw detection of the surface flaw can be realized with extremely high accuracy.

Further, according to the present invention, the mechanism for detecting flaws on the surface is provided at a position above and apart from the corner billet in a severe environment in operation and maintenance. In addition, it is extremely superior in both performance and maintenance as compared with the prior art, and can be provided at low cost, which is extremely advantageous in terms of economy.

[Brief description of the drawings]

FIG. 1 is a line configuration diagram of a magnetic particle flaw detector according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a control system of the magnetic particle flaw detector shown in FIG.

3A is a layout diagram of a camera and a distance sensor in a pre-process E in the magnetic particle flaw detector illustrated in FIG. 1;
(B) is a layout diagram of the camera and the distance sensor in the post-process G as well.

FIG. 4 is a flowchart of image processing in the control system shown in FIG. 2;

5A is an explanatory diagram of setting the width position of a flat camera based on the layout of FIG. 3, FIG. 5B is an explanatory diagram of setting the width position of a corner camera, and FIG. It is explanatory drawing of the width position setting in the vicinity of a corner edge.

FIG. 6 is a schematic side view of a first example of a conventional magnetic particle flaw detector.

FIG. 7A is a schematic side view of a second example of the conventional magnetic particle flaw detector, and FIG. 7B is an enlarged view of the vicinity of the billet in FIG.

[Explanation of symbols]

1: Square billet 2: Transport roller
3. Pinch roller 4. Process computer 5. First control system
6 second control system 7 monitor 8 marking control device
9A ... A plane camera 9B ... B plane camera 9C ... C plane camera
9D… D plane camera 9AB… AB corner camera 9BC… BC corner camera
9CD: CD corner camera 9DA: DA corner camera 10: Ultraviolet light source
11: Overall control device 12: Surface flaw control device 13: Image pre-processing device
14 ... Coordinate conversion device 15A to 15D ... Laser distance sensor
E: Pre-process F: Reversing machine G: Post-process
H: Post-processing step I: Marking step

Continued on the front page F term (reference) 2G051 AA01 AB02 AB07 BA05 BA10 CA04 CA07 CB01 DA06 DA09 DA15 EA08 EA14 EA23 EB01 EC03 EC10 ED23 2G053 AA11 AB21 BA03 BA13 BB03 BB05 BB08 CB27 CC07 DC03 DC20

Claims (4)

[Claims] 1. A square billet which is formed by forming a fluorescent magnetic powder pattern by magnetically attaching fluorescent magnetic powder to a surface flaw portion, and which is provided in opposition to two adjacent upper planes during horizontal conveyance. The fluorescent magnetic powder pattern is imaged by an imaging device including two flat cameras and an upper corner camera provided opposite to an upper corner which is a boundary between upper corner surfaces of upper edges of the two planes, and image preprocessing is performed. After detecting the surface flaws of the square billet by a control system including a surface flaw detection device and a general control device provided with a device, the magnetic particle flaw detection device that is configured to perform marking on the surface flaw portion, A flat camera is provided with two laser distance sensors installed so as to be respectively opposed to the two planes so that the light projecting axes are parallel to each other, and detects a distance between the square billet and the two opposed planes. Calculating the displacement of the angular billet with respect to the horizontal transport center line by introducing a distance signal from the displacement measuring means, and calculating the displacement of the square billet based on the calculation result. Magnetic particle flaw detection, wherein a coordinate conversion means for correcting the position of the flaw by converting the coordinates of the edge portion corresponding to the upper corner of the obtained square billet is provided in association with the control system. Billet lateral shake correction device in the device. 2. A method according to claim 1, wherein the magnetic billet is magnetically adhered to the surface flaws to form a fluorescent magnetic powder pattern.
An A-plane camera and a B-plane camera provided to face the plane and the B-plane, respectively, an AB corner camera provided to face an AB-corner which is a boundary between upper-side edges A and B of the A- and B-planes, A The fluorescent magnetic powder is obtained by a first image pickup device including a DA corner camera provided to face an A horizontal corner surface at a lower edge of a plane and a BC corner camera provided to face a B horizontal corner surface at a lower edge of a B plane. A pattern is imaged, and a first control system including a first surface flaw detection device including a first image preprocessing device and a first general control device detects a surface flaw of the square billet, and a post-process. In the C-plane camera and the D-plane camera provided opposite to the upper C-plane and the D-plane, respectively, adjacent to the square billet obtained by rotating by 180 ° around the longitudinal axis immediately after the previous process,
C which is the upper edge of the C and D planes and which is the boundary of the upper corner surface of C and D
The fluorescent magnetic powder pattern is imaged by a second imaging device having a CD corner camera provided to face the D corner,
A second control system including a second surface flaw detection device including an image pre-processing device and a second general control device detects a surface flaw of the square billet, and thereafter performs marking on the surface flaw portion. In the magnetic particle flaw detection apparatus described above, the light projecting axes are made parallel to the A and B plane cameras, respectively, so that the A, B
Displacement measuring means for detecting the distance between the square billet and the opposing A and B planes provided with two laser distance sensors installed opposite to each other on a plane, and a horizontal signal by introducing a distance signal from the displacement measuring means. Calculate the displacement of the angular billet with reference to the transport center line, and based on the calculation result, correspond to the AB, BC, and DA corners of the angular billet obtained on the image captured by the first image preprocessing device. Coordinate conversion means for correcting the flaw position by converting the coordinates of each edge portion to be formed is provided in relation to the first control system, and the light projecting axes are respectively provided to the C and D plane cameras. Displacement measuring means for detecting the distance between the square billet and the opposing C and D planes, comprising two laser distance sensors installed in parallel to the C and D planes, respectively; The displacement of the angular billet with respect to the horizontal transport center line is calculated by introducing the distance signal from the measuring means, and the angular billet obtained on the image captured by the second image preprocessing device is calculated based on the calculation result. CD corner, B
A magnetic particle flaw detection apparatus comprising: a coordinate conversion means for correcting a flaw position by converting coordinates of each edge portion corresponding to a C corner and a DA corner in relation to the second control system. Billet shake correction device. 3. The conversion of the coordinates of the edge portion in the coordinate conversion means is obtained from the distance signals of two laser distance sensors respectively installed opposite to two planes adjacent on both sides of the edge portion. 3. The billet lateral vibration correcting device in the magnetic particle flaw detection apparatus according to claim 1, wherein a sum Z of displacement vectors is calculated, and a projection X of the vector sum Z onto the horizontal axis is obtained. 4. A control system including a surface flaw detection device and an overall control device divides the angular billet sequentially and horizontally conveyed into a predetermined number of unit blocks and captures an image taken by an image preprocessing device. Is divided into blocks corresponding to the unit block, flaw data is collected for each block, and distance signals of two laser distance sensors are read at regular time intervals during billet inspection, and two laser distances within the block are read for each block. 4. The billet lateral vibration correcting device in the magnetic particle flaw detector according to claim 3, wherein an average displacement is obtained from a distance signal of the sensor, and a flaw position in the block is corrected for each block.