JPH0650941A - Magnetic particle crack detection type surface flaw - Google Patents

Abstract

PURPOSE:To obtain an apparatus, which can positively detect the surface flaw expressed as a magnetic particle pattern without missing and can perform the surface-flaw detecting work efficiently. CONSTITUTION:On a moving truck 1, which can move on a material under inspection S, a magnetizing device 2 for magnetic-particle crack detection, a lighting device 3 for lighting the place of the magnetic-particle pattern expressing a surface flaw, a CCD camera 4, which picks up the image of the magnetic-powder pattern, and a 6-inch type liquid-crystal color display 11, which displays the image signal from the camera 4, are provided. The camera 4 is provided so that the optical angle formed by the optical axis and the surface of the material under inspection becomes 60-90 degrees and the magnification of the image of the size of the magnetic-particle pattern on the screen of the display with respect to the actual size of the magnetic-particle pattern on the material under inspection becomes 0.9-1.2. In this way, the image of the magnetic-particle pattern expressing the surface flaw can be sensed with naked eyes by observing the screen even under the state wherein the moving truck 1 is moved on the material under inspection.

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 detection type surface flaw detection device used for detecting surface flaws in a steel slab by magnetic particle flaw detection, for example, in the steel industry, and more particularly to a surface flaw expressed as a magnetic powder pattern. The present invention relates to a novel magnetic particle flaw detection type surface flaw detection device capable of surely detecting without overlooking and capable of efficiently performing surface flaw detection work.

[0002]

2. Description of the Related Art Conventionally, in order to detect surface flaws such as cracks existing on the surface of a material to be inspected made of a ferromagnetic material, a magnetic device for magnetic particle flaw detection has been used to pass a magnetic flux through the material to be inspected. By adsorbing the supplied magnetic powder to the surface flaw part by the magnetic field generated by the magnetic flux leaking at that part,
The surface flaws are expressed as a magnetic powder pattern (indicating pattern with magnetic powder),
As a result, it is possible to visually observe surface flaws that are difficult to recognize with the naked eye, and the surface flaws are detected by allowing the observer to visually recognize the presence or absence of this magnetic powder pattern, its position, size, etc. .

In visually observing the magnetic powder pattern, the surface of the material to be inspected is irradiated with visible light or near-ultraviolet light to illuminate the portion of the magnetic powder pattern that indicates a surface flaw, and the observer sits down on the waist. The eyes are approached to several tens of centimeters from the surface of the material to be inspected, and the presence, absence, position, size, etc. of the magnetic powder pattern are visually observed. It should be noted that the magnetic powder pattern has a length of, for example, a dozen mm.
Hereafter, the width is a few mm or less.

[0004]

In the surface flaw detection method based on the magnetic particle flaw detection method described above, the surface flaw is detected for a material to be inspected having a flat surface and a large surface area, such as a billet or a thick steel plate in the steel industry. In this case, the observer places his / her eyes directly on the surface of the material to be inspected and visually observes the presence or absence of the magnetic powder pattern. However, there is a problem that it takes time to detect the surface flaw. Further, there is a problem that the surface flaw is easily overlooked due to the fatigue of the observer coming from an unreasonable posture.

Therefore, an object of the present invention is to provide a novel magnetic particle flaw detection type surface flaw detection apparatus capable of surely detecting a surface flaw expressed as a magnetic powder pattern without overlooking it and efficiently performing a surface flaw detection work. To do.

[0006]

In order to achieve the above object, a magnetic particle flaw detection type surface flaw detection device according to the present invention is provided with a movable carriage that is movable on a material to be inspected, and a movable carriage provided on the movable carriage. Magnetic flux that passes magnetic flux through the inspection material and attracts the magnetic powder scattered and supplied from the outside to the surface flaw portion of the inspection material by the magnetic field generated by the magnetic flux leaked at that portion, thereby expressing the surface flaw of the inspection material as a magnetic powder pattern A magnetizing device for flaw detection, an illumination light source that is provided on the movable carriage and that irradiates a surface of a material to be inspected with light obliquely from above in order to illuminate a magnetic powder pattern portion indicating a surface flaw, and the movable carriage that has surface defects An image pickup device for picking up an image of the surface of a material to be inspected to pick up an image of a magnetic powder pattern showing the image, and displaying an image by receiving a video signal from the image pickup device, and visually observing the image to show a magnetic powder pattern image showing a surface flaw. Perceive Whereby an image display device for detecting a surface flaw of the test material, the imaging device,
The optical axis forms an angle of 60 to 90 degrees with the surface of the material to be inspected, and the magnification of the image size of the magnetic powder pattern on the screen of the image display device is 0.9 to the actual size of the magnetic powder pattern on the material to be inspected. It is characterized in that it is provided so as to be 1.2.

[0007]

In the magnetic particle flaw detection type surface flaw detecting device according to the present invention, while the moving carriage is moved over the material to be inspected, the magnetic flux for magnetic particle flaw detection is provided by the magnetizing device for magnetic particle flaw detection provided in the moving carriage. . As a result, the magnetic powder scattered and supplied from the outside is adsorbed to the surface flaw portion by the magnetic field generated by the magnetic flux leaking at that portion, and the surface flaw present on the surface of the material to be inspected is expressed as a magnetic powder pattern. Then, the illumination light source provided on the moving carriage illuminates the surface of the material to be inspected obliquely from above to illuminate the magnetic powder pattern portion indicating the surface flaw, and the imaging device provided on the moving carriage makes The surface of the inspection material is imaged, and an image of a magnetic powder pattern representing surface flaws is captured. The image signal from this image pickup device is displayed on the image display device, and the image displayed on the screen of the image display device is displayed without the observer's eyes approaching the surface of the material to be inspected in an unreasonable posture. By visually observing and perceiving the magnetic powder pattern image showing the surface flaw, the surface flaw of the material to be inspected is detected.

As described above, the surface flaw detection apparatus according to the present invention illuminates the surface of the material to be inspected obliquely from above while moving the movable carriage on the material to be inspected, while moving it. The surface of the material to be inspected is imaged by the imaging device provided on the dolly, a magnetic powder pattern image showing surface flaws is taken, and the video signal from the imaging device is displayed on the image display device. It is designed so that a magnetic powder pattern image showing a flaw is perceived.

For this reason, the image pickup device is displayed on the screen of the image display device so that the optical axis forms an angle of 60 to 90 degrees with the surface of the material to be inspected and the actual size of the magnetic powder pattern on the material to be inspected. Magnification of magnetic powder image size is 0.9 to 1.
By disposing so that even if the moving carriage is moving on the material to be inspected, the magnetic powder pattern image showing a small and slight surface flaw can be seen from the image of the magnetic powder pattern even when the moving carriage is moving on the inspected material. Even a magnetic powder pattern image showing is perceptible to the naked eye. Hereinafter, this point will be described.

First, in a stationary state, an angle α formed by the optical axis of the illumination light source with the surface of the material to be inspected (hereinafter referred to as an optical axis angle of the illumination light source) and an angle β formed by the optical axis of the image pickup device with the surface of the material to be inspected. (Hereinafter, referred to as an optical axis angle of the image pickup device) and the influence on the perceptibility of the magnetic powder pattern image on the screen of the image display device by the naked eye were investigated. In this investigation, a magnetic powder pattern showing small and slight surface flaws, a magnetic powder pattern showing medium-sized surface flaws, and a magnetic powder showing large and serious surface flaws on the surface of an inspected material having a flat surface and a large surface area. A large number of three types of magnetic powder patterns are formed, and an image of the magnetic powder pattern is taken by changing the optical axis angle α of the illumination light source and the optical axis angle β of the imaging device, and at that time, on the screen of the image display device. It was carried out by visually observing the displayed image. here,
The field of view of the imaging device is 70 in the longitudinal direction (horizontal scanning line direction).
The magnification of the magnetic powder pattern image size on the screen of the image display device with respect to the actual size of the magnetic powder pattern on the inspected material was set to 1 × (1.0). In addition, CC as an imaging device
A 6-inch liquid crystal color display (liquid crystal color monitor) was used as a D color camera and an image display device.
The results are shown in Table 1.

[0011]

[Table 1]

From Table 1, even when the optical axis angle α of the illumination light source is set over a wide range, by providing the image pickup device so that the optical axis angle β is 60 to 90 degrees, Looking at the screen, it can be seen that the magnetic powder pattern image showing a small and slight surface flaw to the magnetic powder pattern image showing a large and serious surface flaw can be perceived by the naked eye. As can be seen from Table 1, the optical axis angle β of the imaging device and the optical axis angle α of the illumination light source may be set to different values in order to prevent halation and the like due to specular reflection light. preferable.

Next, when the movable carriage is being moved on the material to be inspected, the magnification of the image size of the magnetic powder pattern on the screen of the image display device with respect to the actual size of the magnetic powder pattern on the material to be inspected is the image display device screen. The effect of the above magnetic powder pattern image on the perceptibility by the naked eye was investigated.

In this investigation, the moving carriage is in a stationary (stopped) state,
In addition, while the moving carriage was moved at a speed of about 150 mm / sec, the above three types of magnetic powder pattern images were taken, and the image displayed on the screen at that time was visually observed. Here, the optical axis angle β of the imaging device is 75 degrees, the optical axis angle α of the illumination light source is 70 degrees, and the visual field size of the imaging device is
The length (horizontal scanning line direction) was set to 70 mm or more. The results are shown in Table 2.

[0015]

[Table 2]

The results are shown in Table 2. As can be understood from Table 2, the distance between the imaging device and the surface of the material to be inspected, or the camera lens thereof is appropriately selected, and the magnetic powder on the screen of the image display device is compared with the actual size of the magnetic powder pattern on the material to be inspected. By providing the pattern image with a magnification of 0.9 to 1.2, the magnetic powder showing small and slight surface flaws can be seen by looking at the screen of the image display device even when the moving carriage is moving on the material to be inspected. It is possible to visually perceive from a pattern image to a magnetic particle pattern image showing a large and serious surface flaw. In this way, it is possible to surely detect the surface flaw represented by the magnetic powder pattern without overlooking, and it is possible to efficiently perform the surface flaw detection work.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below. FIG. 1 is a diagram showing the structure of a magnetic particle flaw detection type surface flaw detection apparatus according to an embodiment of the present invention, and FIG. 2 is a side view of the magnetic particle flaw detection type surface flaw detection apparatus shown in FIG.

In FIGS. 1 and 2, reference numeral 1 denotes a moving carriage which is moved manually on an inspected material S whose surface flaw is to be detected by an observer. In this embodiment, the movable carriage 1 has a pipe-assembled structure as a whole. Wheels 1a are attached to the four corners of the bottom portion, and a box-shaped frame portion that is open except for the ceiling plate portion is provided at the top end portion. U-shaped grip arm 1b
The rod-shaped arm 1c to which is attached is fixed. Inside the box-shaped frame portion of the moving carriage 1, as shown in the figure, a magnetizing device for magnetic particle flaw detection is provided with a pair of rollers 2a (not shown in FIG. 2) rolling on the material S to be inspected. 2, an illumination light source 3, and a CCD color camera 4 as an imaging device are provided in a state of being attached to a box-shaped frame portion.

The magnetizing device 2 for magnetic particle flaw detection provided with a pair of rollers 2a passes magnetic flux through the material S to be inspected, and the magnetic particles scattered and supplied from the outside are leaked to the surface flaw portion of the material to be inspected. Is a device for expressing the surface flaw of the material to be inspected as a magnetic powder pattern by being attracted by the magnetic field generated by the. It is a light source that emits light at the optical axis angle α described above. These are attached to the box-shaped frame portion of the movable carriage 1 by a support member (not shown). The CCD color camera 4 is for capturing the surface of the material to be inspected so as to capture an image of a magnetic powder pattern that represents surface defects.

Reference numeral 5 is a first mounting plate, and 6 is a second mounting plate, which support the CCD color camera 4 so that its optical axis angle β and its distance to the inspection object S can be adjusted. It is for doing. As shown in FIG. 1, the first mounting plate 5 having a wide arc shape and having a circular arc shape is provided with two camera optical axis angle adjusting holes 5a extending in a circular arc shape and penetrating the plate. The rectangular second mounting plate 6 fixed to the first mounting plate 5 is provided with a hole 6a for adjusting the distance between inspection materials, which penetrates the plate and extends in the vertical direction in the drawing. Reference numeral 7 denotes a third mounting plate fixed to the upper pipe 1d, which is one of the constituent members of the box-shaped frame portion of the movable carriage 1.

The second mounting plate 6 fixed to the first mounting plate 5 is passed through the fixing bolt 9 through the hole 6a for adjusting the distance between the materials to be inspected, and screwed into the female screw engraved on the third mounting plate 7. By doing so, it is fixed to the upper pipe 1d of the movable carriage 1. Then, in the CCD color camera 4, the four fixing bolts 8 are passed through the camera optical axis angle adjusting holes 5a of the first mounting plate 5, and C
The CD color camera 4 is fixed to the first mounting plate 5 by being screwed into a female screw engraved in the housing of the CD color camera 4. Therefore, the adjustment of the optical axis angle β of the CCD color camera 4 is
This is done by tightening the fixing bolts 8 after moving the camera 4 to a predetermined position along the camera optical axis angle adjusting hole 5a with the four fixing bolts 8 loosened. The distance between the CCD color camera 4 and the material S to be inspected is adjusted by moving the camera 4 up and down together with the integrated mounting plates 5 and 6 to a predetermined position with the fixing bolt 9 loosened. This is done by tightening 9.

On the ceiling plate of the box-shaped frame portion of the movable carriage 1, C
A camera controller 10 for amplifying a video signal from the CD color camera 4 is provided. In this embodiment, the amplified video signal, sync signal and the like from the camera controller 10 are given to a 6-inch liquid crystal color display 11 as an image display device attached to the arm 1c of the moving carriage 1, A video signal from the CCD color camera 4 is displayed as an image on the 6-inch liquid crystal color display 11,
The image is visually observed by an observer.

Using the magnetic particle flaw detection type surface flaw detection apparatus of this embodiment having the above-described structure, the surface flaw detection on the steel piece as the material S to be inspected was carried out under the following set conditions. The setting conditions are: the field of view of the CCD color camera 4: 70 mm or more in the longitudinal direction (horizontal scanning line direction), the moving speed of the moving carriage 1:
Approximately 150 mm / sec, the optical axis angle α of the illumination light source 3 at a pitch of 5 degrees
50 to 80 degrees, the optical axis angle β of the CCD color camera 4 is 60 to 90 degrees at a pitch of 5 degrees, and the magnetic powder pattern image size on the screen of the 6-inch liquid crystal color display 11 with respect to the actual size of the magnetic powder pattern on the inspected material S Magnification: 0.9 to 0.1 pitch
1.2. In this case, the magnification is changed by the distance between the CCD color camera 4 and the surface of the material to be inspected or by appropriately selecting the camera lens. Further, in order to prevent halation and the like due to specular reflection light, a combination in which the optical axis angle β of the CCD color camera 4 and the optical axis angle α of the illumination light source 3 are the same is avoided.

As a result, even when the moving carriage 1 is moved at a speed of about 150 mm / sec, the screen of the 6-inch type liquid crystal color display 11 is seen, and the surface is small and small without being confused with the pseudo pattern. From the magnetic powder pattern image showing a flaw to the magnetic powder pattern image showing a large and serious surface flaw can be perceived by the naked eye, which enables reliable detection without overlooking the surface flaw expressed as a magnetic powder pattern and the surface flaw detection work. I was able to do it efficiently.

[0025]

As described above, according to the magnetic particle flaw detection type surface flaw detection apparatus of the present invention, the surface flaw formed by the magnetic particle flaw detection magnetizing apparatus and the magnetic particle flaw detection magnetizing apparatus is provided on the movable carriage that can move on the material to be inspected. Is provided with an illuminating light source for illuminating a magnetic powder pattern portion that represents a magnetic powder pattern, and an image pickup device for picking up an image of a magnetic powder pattern showing a surface flaw, and an image display device for displaying a video signal from the image pickup device. In addition, the image pickup device has a magnetic powder pattern image on the screen of the image display device with respect to the actual size of the magnetic powder pattern on the inspection material such that the angle formed by the optical axis of the imaging device and the surface of the inspection material is 60 to 90 degrees. Since the dimensional magnification is set to 0.9 to 1.2, even when the moving carriage is moving on the material to be inspected, the small and slight surface flaws can be seen by looking at the screen of the image display device. Porcelain From the pattern image to the magnetic powder image that shows large and serious surface flaws can be perceived by the naked eye, which enables reliable detection without overlooking the surface flaws that are expressed as magnetic powder flaws, and efficient surface flaw detection work. You can

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of a magnetic particle flaw detection type surface flaw detection apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of the magnetic particle flaw detection type surface flaw detection device shown in FIG.

[Explanation of symbols]

1 ... Mobile trolley 1a ... Wheel 1b ... Grip arm 1c ... Arm
1d ... Upper pipe 2 ... Magnetizer for magnetic particle flaw detection 2a ... Roller 3 ... Illumination light source 4 ... CCD color camera 5 ... First mounting plate 5a ... Camera optical axis angle adjusting hole 6 ... Second mounting plate 6a ... Between inspected materials Distance adjusting hole 7 ... Third mounting plate
8, 9 ... Fixing bolt 10 ... Camera controller 11 ... 6 inch type liquid crystal color display S ... Inspected material

Claims (1)

[Claims] 1. A movable carriage capable of moving on a material to be inspected, and a magnetic powder which is provided on the movable carriage and allows magnetic flux to pass through the material to be inspected and which is sprayed and supplied from the outside to a surface flaw portion of the material to be inspected. In order to illuminate the magnetic flaw detection magnetizing device that shows the surface flaws of the material to be inspected as a magnetic powder pattern and the moving carriage that is provided with the magnetic powder generated by the magnetic flux generated by the magnetic flux leaked at An illumination light source that irradiates the surface of the material to be inspected with light obliquely from above, an imaging device that is provided on the movable carriage and that images the surface of the material to be inspected to capture an image of a magnetic powder pattern that represents surface defects, and from this imaging device Image display in response to the image signal of, to perceive a magnetic powder pattern image representing surface flaws by visually observing the image, thereby comprising an image display device for detecting surface flaws of the material to be inspected,
The angle between the optical axis of the image pickup device and the surface of the material to be inspected is
It is provided such that the magnification of the magnetic powder pattern image size on the screen of the image display device with respect to the actual size of the magnetic powder pattern on the inspected material is 0.9 to 1.2 so as to be 60 to 90 degrees. Magnetic particle flaw detection type surface flaw detector.