JP2009075098A - Apparatus and method for measuring magnetic powder concentration - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To instantly and quantitatively determine magnetic powder concentration of fluorescent magnetic powder liquid. <P>SOLUTION: This apparatus for measuring magnetic powder concentration includes a standard test body 2 having, on its whole surface, a false defect section 4a to which the fluorescent magnetic powder of a fluorescent magnetic powder liquid adheres by magnetic pole. This measuring apparatus further includes an ultraviolet irradiation section 5 for irradiating the standard test body 2, to which the fluorescent magnetic powder adheres, with ultraviolet light and causing fluorescent magnetic powder to emit light, an imaging device 6 for photographing the standard test body 2 and obtaining an image signal, and a processing unit 7b for calculating a brightness value of the light of the fluorescent magnetic powder from this image signal and converting the brightness value into magnetic powder concentration. Thus, the magnetic powder concentration of the fluorescent magnetic powder liquid can be instantly and quantitatively recognized, and accurate concentration of the fluorescent magnetic powder can be measured without causing difference between inspecting persons. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic powder concentration measuring apparatus and a magnetic powder concentration measuring method for measuring the concentration of fluorescent magnetic powder dispersed in a fluorescent magnetic powder liquid for magnetic particle flaw detection of inspection objects such as steel materials and steel parts.

  In general, wet fluorescent magnetic particle testing is used to inspect defects such as scratches on inspected objects such as steel materials and steel parts.

  The wet fluorescent magnetic particle flaw detection test method is a flaw detection test method in which a defect is detected by magnetizing an object to be inspected and using magnetic poles attached to the defect by a magnetic pole generated in the defect.

  In this wet fluorescent magnetic particle flaw detection test method, a defective portion of an inspection object is detected as follows. First, an object to be inspected such as a steel material or steel part is magnetized. Then, the defective part of the object to be inspected has leakage magnetic flux and has a magnetic pole. Next, a fluorescent magnetic powder is sprayed on the magnetized test object. Thereby, the fluorescent magnetic powder dispersed in the fluorescent magnetic powder liquid adheres to the defect portion of the inspection object by the magnetic pole. Then, in the dark room, the inspection object sprayed with the fluorescent magnetic powder liquid is irradiated with ultraviolet light to cause the fluorescent magnetic powder to emit light. As a result, the defective part of the object to be inspected can be detected visually by the fluorescent magnetic powder adhering to the defective part emitting light. This wet fluorescent magnetic particle flaw detection test method has an effect that even a fine defect can be easily found because of high fluorescence luminance.

  This fluorescent magnetic powder liquid is composed of fluorescent magnetic powder of about 2 to 10 μm (iron powder to which a phosphor is attached), water or white kerosene, and a predetermined amount of dispersant.

  In addition, the dispersion concentration (magnetic powder concentration) of the fluorescent magnetic powder in the fluorescent magnetic powder liquid is the accuracy of visual detection of the fluorescent luminance at the defective portion of the inspection object, that is, the fluorescent luminance pattern obtained from the inspection object and the information obtained from it. It is a big factor that influences.

  As a conventional magnetic powder concentration (fluorescent magnetic powder) magnetic powder concentration measuring method, there are the following methods. In this conventional magnetic powder concentration measurement method, first, the magnetic powder liquid in which the magnetic powder is dispersed is well stirred. Next, a prescribed amount (100 ml) of the magnetic powder is collected in a sedimentation tube, and this sedimentation tube is placed on a stand. Then, after 30 minutes have elapsed, the amount of magnetic powder precipitated on the bottom of the settling tube is visually measured.

  Further, as another example of the magnetic powder concentration measuring method of the magnetic powder liquid, there is one described in Patent Document 1. The magnetic powder concentration measuring method described in Patent Document 1 is performed as follows. First, several kinds of magnetic powder liquids having known magnetic powder concentrations are applied to a standard test piece in advance to form several kinds of comparative magnetic powder patterns. Next, a magnetic powder solution to be measured, that is, a magnetic powder solution whose magnetic powder concentration is unknown, is applied to this standard test piece to form a magnetic powder pattern for measurement. And several types of magnetic powder patterns for comparison and magnetic powder patterns for measurement are visually compared to measure the magnetic powder concentration of the magnetic powder liquid whose magnetic powder concentration is unknown.

JP-A-7-113787

  However, in the conventional magnetic powder concentration measurement method, when the particle size of the fluorescent magnetic powder is about 2 to 10 μm, the fluorescent magnetic powder is light even if 30 minutes elapses after standing the settling tube into which the fluorescent magnetic powder liquid is injected. Only a part of the fluorescent magnetic powder was deposited on the bottom of the settling tube. Therefore, the conventional magnetic powder concentration measurement method has a problem that the amount of fluorescent magnetic powder cannot be measured accurately. Furthermore, there is a disadvantage that it takes too much time to measure the magnetic powder concentration.

  Moreover, since the method disclosed in Patent Document 1 is a visual measurement, a difference occurs depending on the person to be inspected. As a result, with the magnetic powder concentration measurement method disclosed in Patent Document 1, it was difficult to accurately measure the magnetic powder concentration.

  In view of the above-described problems, an object of the present invention is to make it possible to instantaneously quantitatively confirm and evaluate the magnetic powder concentration of a fluorescent magnetic powder liquid.

  In order to solve the above problems and achieve the object of the present invention, the magnetic powder concentration measuring apparatus of the present invention is provided with a standard test body having a pseudo defect portion on one side to which the fluorescent magnetic powder of the fluorescent magnetic powder liquid adheres by magnetic poles. Further, an ultraviolet irradiation unit for irradiating the standard test body to which the fluorescent magnetic powder adheres with ultraviolet light to emit the fluorescent magnetic powder, and an imaging device for photographing the standard test body irradiated with ultraviolet light and obtaining an image signal are provided. . And the processing part which calculates the luminance value of the fluorescent magnetic powder light-emitted from this image signal, and converts a luminance value into a magnetic powder density | concentration was provided.

  In addition, the magnetic powder concentration measuring method of the present invention includes a step of attaching fluorescent magnetic powder of fluorescent magnetic powder liquid to a pseudo-defect portion provided on one surface of a standard test specimen with a magnetic pole. Next, the method includes a step of irradiating the standard test specimen to which the fluorescent magnetic powder is adhered with ultraviolet light to emit the fluorescent magnetic powder, and a step of photographing the standard test specimen irradiated with the ultraviolet light to obtain an image signal. And calculating a luminance value of the fluorescent magnetic powder emitted from the image signal and converting the calculated luminance value into a magnetic powder concentration.

  According to the present invention, the fluorescent magnetic powder of the fluorescent magnetic powder is emitted to obtain an image signal, and a luminance value is calculated from the image signal. Then, by converting this luminance value into a magnetic powder concentration, the magnetic powder concentration of the fluorescent magnetic powder liquid can be instantaneously and quantitatively confirmed. Furthermore, there is no difference depending on the person to be inspected, and an accurate concentration of the fluorescent magnetic powder can be measured.

  Hereinafter, an example of an embodiment (hereinafter referred to as “this example”) for carrying out the magnetic powder concentration measuring apparatus and the magnetic powder concentration measuring method of the present invention will be described with reference to the drawings.

1. Configuration of Magnetic Powder Concentration Measuring Device First, the magnetic powder concentration measuring device in this example will be described with reference to FIGS. FIG. 1 shows a configuration of a magnetic powder concentration measuring apparatus in this example. FIG. 2 is a perspective view showing a first embodiment of a standard test specimen according to the magnetic powder concentration measuring apparatus of the present invention. FIG. 3 is a block diagram showing a schematic configuration of the magnetic powder concentration measuring apparatus in this example.

  As shown in FIG. 1, a magnetic particle concentration measuring apparatus 100 includes a standard test specimen 2 arranged at a predetermined position in a dark room 1, a black light 5 as an ultraviolet irradiation unit, a CCD camera 6, and a measurement unit. A personal computer 7 showing a specific example and a memory 8 are included.

[Standard specimen]
As shown in FIG. 2, the standard test body 2 includes a substantially cylindrical outer casing 2 a, a magnet 3, and a substantially circular iron plate 4. The outer casing 2a is formed in a substantially cylindrical shape, and one end in the axial direction is opened and the other end in the axial direction is closed. The outer casing 2a is made of, for example, a synthetic resin. A magnet 3 is accommodated in the outer casing 2a. Furthermore, a substantially circular iron plate 4 is attached so as to close the opening of the outer casing 2a. On one surface of the iron plate 4, for example, a pseudo defect portion 4 a formed in a circular shape is disposed. In the pseudo defect portion 4a, a defect portion is intentionally formed by grinding or stress corrosion. And this pseudo defect part 4a is magnetized by the magnet 3 accommodated in the outer casing 2a.

  In addition, although the example which formed the shape of the standard test body 2 in the substantially cylindrical shape was demonstrated in this example, it is not limited to this. For example, the standard specimen 2 may be formed in a prismatic shape, and the iron plate 4 may be formed in a substantially square shape.

[Ultraviolet irradiation unit and imaging device]
Further, as shown in FIG. 1, in the dark room 1, above the standard specimen 2, a black light 5 indicating the ultraviolet irradiation section of the present invention and a CCD camera 6 showing a specific example of the imaging apparatus of the present invention are provided. Is provided. The black light 5 irradiates one surface (pseudo defect portion 4 a) of the iron plate 4 provided on the standard specimen 2 in the dark room 1 with ultraviolet light. The CCD camera 6 captures the pseudo defect 4a irradiated with the ultraviolet light by the black light 5 to obtain an image signal. The CCD camera 6 is connected to a personal computer 7 and supplies the captured image signal to the personal computer 7. Needless to say, not only the CCD camera but also a COMS camera or the like may be applied to the imaging device.

[Measurement section]
As shown in FIG. 3, the personal computer 7 includes a display unit 7a and a processing unit 7b. The processing unit 7b includes a luminance value calculation unit 71, a magnetic powder concentration conversion unit 72, and the like. The luminance value calculation unit 71 performs processing for calculating a luminance value from an image signal photographed by the CCD camera 6. The luminance value calculation unit 71 is connected to the magnetic powder concentration conversion unit 72. The magnetic powder concentration conversion unit 72 performs a process of converting the magnetic powder concentration from the luminance value calculated by the luminance value calculation unit 71. And the luminance value calculating part 71 and the magnetic powder density | concentration conversion part 72 are connected to the display part 7a.

  The display unit 7 a displays an image of the standard specimen 2 taken by the CCD camera 6, the luminance value calculated by the luminance value calculation unit 71, the magnetic powder concentration converted by the magnetic powder concentration conversion unit 72, and the like. Further, the personal computer 7 is connected to a memory 8 showing a specific example of the storage unit of the present invention so as to be able to transmit and receive. The personal computer 7 has an input unit such as a keyboard and a mouse. From this input unit, data such as the type of fluorescent magnetic powder, the type of standard test specimen, and the concentration of known fluorescent magnetic powder for creating luminance value-magnetic powder concentration conversion data 81 to be described later are input.

[Storage unit]
The memory 8 stores luminance value-magnetic powder concentration conversion data 81 indicating the relationship between the magnetic powder concentration and the luminance value. Then, based on the luminance value-magnetic powder concentration conversion data 81 stored in the memory 8, the magnetic powder concentration conversion unit 72 of the personal computer 7 converts the luminance value into the magnetic powder concentration, so that the magnetic powder concentration of the fluorescent magnetic powder liquid. Is measured.

  The personal computer 7 and the memory 8 may be connected via a network such as a public communication line, a dedicated line, and the Internet.

2. Method for Creating Brightness Value-Magnetic Powder Concentration Conversion Data Next, a method for creating the luminance value-magnetic powder concentration conversion data stored in the memory 8 will be described. Here, an example in which LY-10 manufactured by Martech Co., Ltd. is used as the fluorescent magnetic powder will be described. This LY-10 has a particle size of 3 to 7 μm and is exclusively for water dispersion.
First, a plurality of fluorescent magnetic powders 10a having known magnetic powder concentrations having different concentrations are prepared. In this example, the fluorescent magnetic powder liquid has a magnetic powder concentration of 0.1 g / l, 0.2 g / l, 0.3 g / l, 0.4 g / l, 0.5 g / l, 1 g / l, 1.5 g / l. Prepare.

  FIG. 4 is a view showing a state in which a standard test specimen is immersed in a fluorescent magnetic powder solution. Next, as shown in FIG. 4, these fluorescent magnetic powder liquids 10 a are respectively injected into the magnetic powder liquid tank 10. And the standard test body 2 is immersed in the magnetic powder liquid tank 10 in which the fluorescent magnetic powder liquid 10a is injected for a predetermined time. Here, the pseudo defect portion 4 a provided in the standard test body 2 is magnetized by the magnet 3. Therefore, a magnetic pole is generated in the pseudo defect portion 4a. As a result, the fluorescent magnetic powder of the fluorescent magnetic powder liquid adheres to the pseudo defect portion 4a by the magnetic pole generated in the pseudo defect portion 4a of the standard specimen 2. The fluorescent magnetic powder may be applied to one surface of the iron plate 4 of the standard specimen 2 so that the fluorescent magnetic powder of the fluorescent magnetic powder is attached to the pseudo defect portion 4a.

  Next, as shown in FIG. 1, the standard test body 2 to which the fluorescent magnetic powder is attached is disposed at a predetermined position in the dark room 1. Then, the black defect 5 is used to irradiate the pseudo-defect portion 4 a of the standard specimen 2 with ultraviolet light. Thereby, the fluorescent magnetic powder adhering to the pseudo defect part 4a emits light. Next, the pseudo defect portion 4 a irradiated with the ultraviolet light is photographed by the CCD camera 6. Then, the image signal photographed by the CCD camera 6 is supplied to the personal computer 7.

  Next, the processing unit 7 b of the personal computer 7 obtains a luminance value from the image signal by the luminance value calculation unit 71. That is, the luminance value calculation unit 71 first obtains an actually measured luminance value by measuring the brightness (brightness value) of each location in the fluorescent magnetic powder that is attached to the pseudo defect portion 4a and emits light. Then, an average luminance value is calculated from the actually measured luminance value, and this average luminance value is set as the luminance value. In this example, for each magnetic powder concentration of the fluorescent magnetic powder, “12” at 0.1 g / l, “18” at 0.2 g / l, “23” at 0.3 g / l, “23” at 0.4 g / l. A luminance value of “47” is obtained at 28 ”, 0.5 g / l“ 35 ”, 1 g / l“ 47 ”, and 1.5 g / l.

  And FIG. 5 is a graph which shows the relationship between the luminance value obtained by the method mentioned above, and a magnetic-powder density | concentration. As shown in FIG. 5, it can be seen that the higher the magnetic powder concentration of the fluorescent magnetic powder liquid is, the more fluorescent magnetic powder is attached to the pseudo-defect portion 4a, and the luminance value (light emission luminance value) is higher.

  Thereby, the luminance value-magnetic particle concentration conversion data 81 indicating the relationship between the magnetic particle concentration and the luminance value can be created. As shown in FIG. 3, the luminance value calculated by the luminance value calculation unit 71 is stored in the memory 8 as luminance value-magnetic particle concentration conversion data 81 together with a known magnetic particle concentration input from an input unit (not shown). .

3. Next, a method for measuring the magnetic powder concentration of an unknown fluorescent magnetic powder liquid will be described with reference to FIGS. 1, 3, and 6. FIG. FIG. 6 is a flowchart showing a method for measuring the magnetic powder concentration. In addition, the fluorescent magnetic powder of the fluorescent magnetic powder liquid measured here uses LY-10 which is the same as the fluorescent magnetic powder used when the brightness value-magnetic powder concentration conversion data 81 described above is created.

  First, as shown in FIG. 4, a fluorescent magnetic powder with an unknown magnetic powder concentration is injected into the magnetic powder tank 10. Next, the standard test body 2 is immersed in the magnetic powder solution tank 10 into which the fluorescent magnetic powder solution has been injected for a predetermined time. As a result, the fluorescent magnetic powder of the fluorescent magnetic powder liquid adheres to the pseudo defect portion 4a by the magnetic pole generated in the pseudo defect portion 4a of the standard specimen 2 as in the case of the above-described method of creating the luminance value-magnetic powder concentration conversion data. (Step S1). In addition, you may adhere the fluorescent magnetic powder of a fluorescent magnetic powder liquid to the pseudo defect part 4a by apply | coating a fluorescent magnetic powder liquid to the pseudo defect part 4a of the standard test body 2. FIG.

  Next, the standard test body 2 to which the fluorescent magnetic powder of the fluorescent magnetic powder is adhered is placed at a predetermined position in the dark room 1. Then, the standard specimen 2 is irradiated with ultraviolet light using the black light 5 (step S2). Then, the fluorescent magnetic powder adhering to the pseudo defect portion 4a emits light. Here, when the ultraviolet irradiation intensity of the black light 5 changes, the luminance value, which is the brightness of light emission of the fluorescent magnetic powder, also changes. Therefore, it is preferable to make the irradiation intensity of the black light 5 constant with the irradiation intensity at the time of creating the luminance value-magnetic powder concentration conversion data 81 described above. Next, the pseudo defect portion 4a irradiated with the ultraviolet light is photographed by the CCD camera 6 (step S3). The image signal captured by the CCD camera 6 is supplied to the personal computer 7.

  Next, the processing unit 7b of the personal computer 7 calculates the luminance value from the image signal by the luminance value calculating unit 71 (step S4). And the process part 7b of the personal computer 7 converts the acquired luminance value into a magnetic powder density | concentration by the magnetic powder density | concentration conversion part 72 (step S5). That is, the processing unit 7 b calls the brightness value-magnetic powder concentration conversion data 81 stored in the memory 8. And the process part 7b is collated with the brightness | luminance value-magnetic powder density | concentration conversion data 81 by the magnetic powder density | concentration conversion part 72, and converts it into the magnetic powder density | concentration of a fluorescent magnetic powder liquid. Thereby, the measurement of the magnetic powder concentration of the fluorescent magnetic powder liquid whose magnetic powder concentration is unknown is completed.

  FIG. 7 shows an example of a screen displayed on the display unit 7a. As shown in FIG. 7, the display unit 7 a of the personal computer 7 includes an image 73 of the standard specimen 2 taken by the CCD camera 6, a luminance value calculated by the luminance value calculation unit 71, and a magnetic powder concentration conversion unit 72. The converted magnetic powder concentration 74 or the like is displayed.

  Thereby, according to the magnetic powder density | concentration measuring method of this invention, the density | concentration of fluorescent magnetic powder liquid can be quantitatively measured from a luminance value by collating with luminance value-concentration conversion data. Therefore, the magnetic powder concentration can be measured accurately and instantaneously without causing a difference depending on the person to be inspected.

FIG. 8 is a graph showing the relationship between the luminance value and the magnetic powder concentration in a plurality of different types of fluorescent magnetic powder.
A curve b shown in FIG. 8 is a graph showing the relationship between the luminance value and the magnetic powder concentration when LY-20P manufactured by Martech is used as the fluorescent magnetic powder. This LY-20P has a particle size of 3 to 7 μm and is dedicated to high-luminance water dispersion. A curve c shown in FIG. 8 is a graph showing the relationship between the luminance value and the magnetic powder concentration in the case where LY-50 manufactured by Martec is used as the fluorescent magnetic powder. This LY-50 has a particle size of 3 to 7 [mu] m, similar to LY-20P, and is exclusively used for general purpose oil dispersion.

  Moreover, the curve d shown in FIG. 8 is a graph which shows the relationship between the luminance value and magnetic powder density | concentration which show the case where LY-30 by Martech Co., Ltd. is used for fluorescent magnetic powder. This LY-30 has a particle size of 1 to 4 μm and is for ultra-precision inspection. The curve a shown in FIG. 8 is the same as the graph shown in FIG. 5 and shows the case where LY-10 manufactured by Martec is used as the fluorescent magnetic powder.

  Data indicating the relationship between the luminance value and the magnetic particle concentration in the plurality of fluorescent magnetic particles shown in FIG. 8 is stored in the memory 8 as luminance value-magnetic particle concentration conversion data 81. In this way, the luminance value-magnetic powder concentration conversion data 81 of a plurality of different fluorescent magnetic powders is stored in the memory 8 respectively. In this case, before measuring the magnetic powder concentration, the type of fluorescent magnetic powder to be measured is input to the personal computer 7 through the input unit. And the process part 7b calls the luminance value-magnetic powder density | concentration conversion data of the same fluorescent magnetic powder as the fluorescent magnetic powder input from the memory 8, and converts a luminance value into magnetic powder density. As a result, it is possible to measure the magnetic powder concentration of not only one type of fluorescent magnetic powder but also a plurality of different types of fluorescent magnetic powder.

4). Second Embodiment FIG. 9 and FIG. 10 show a second embodiment of the standard specimen. FIG. 9 is a perspective view showing a second embodiment of the standard specimen, and FIG. 10 is a plan view showing the second embodiment of the standard specimen.

  The standard test specimens shown in FIGS. 9 and 10 are those defined by JIS standards, and specifically, are type 1 test specimens defined by JIS Z 2320-2. As shown in FIGS. 9 and 10, the standard test body 20 is formed in a substantially disc shape, and has a through hole 21 at a substantially center. The standard test body 20 has two types of cracks on one surface which is a pseudo defect portion. Of the two types of cracks 24a and 24b that act as defective portions, the relatively coarse crack 24a is formed by grinding. Of the two types of cracks 24a and 24b, the fine crack 24b is formed by stress corrosion. The fluorescent magnetic powder of the fluorescent magnetic powder liquid adheres to one surface of the standard test body 20 provided with the two types of cracks 24a and 24b.

  Further, the standard specimen 20 is permanently magnetized by the current penetration method. Thereby, since the trouble of separately preparing a magnet can be saved, the number of parts can be reduced as compared with the standard test body 2 according to the above-described first embodiment.

  In addition, the standard test body 20 is formed as follows, for example. First, using a steel (grade 90 MnCrV8), grind it flatly until the surface is 9.80 mm ± 0.05 mm. Then, after the grindered steel is held at 860 ° C. ± 10 ° C. for 2 hours, it is quenched in the middle so that the surface hardness is 63 to 70 HRC. Further, the surface of the steel subjected to the quenching treatment is grindered with a target of 20 mm, for example, at a speed of 35 m / s and with a cutting allowance of 0.05 mm per surface. And black oxidation is processed at 145 degreeC-150 degreeC for 1.5 hours. Furthermore, it is magnetized at DC10000A (peak value) by the current penetration method. Thereby, manufacture of the standard test body 20 is completed.

  Further, the method of creating the brightness value-magnetic powder concentration conversion data and the method of measuring the concentration of the fluorescent magnetic powder liquid are the same as those of the standard specimen 2 according to the above-described first embodiment, and thus the description thereof is omitted. Further, even when the standard test specimen 20 having such a configuration is used, the same effects as those obtained when the standard test specimen 2 according to the first embodiment described above is used can be obtained.

  FIG. 11 is a diagram illustrating an image obtained by photographing the state in which the magnetic powder concentration attached to the second standard test specimen emits light with the imaging device. 11A shows a magnetic powder concentration of 0.1 g / l, FIG. 11B shows a magnetic powder concentration of 0.3 g / l, FIG. 11C shows a magnetic powder concentration of 0.5 g / l, FIG. 11D shows a magnetic powder concentration of 1 g / l, and FIG. It is the image which image | photographed the state which the fluorescent magnetic powder liquid in magnetic powder density | concentration 1.5g / l light-emitted with the CCD camera 6. FIG. As shown in FIGS. 11A to 11E, it can be seen that as the concentration of the fluorescent magnetic powder increases, the brightness of the defective portion of the standard specimen 20 becomes brighter.

5). Third Embodiment Next, a case in which a standard specimen according to a third embodiment is used will be described with reference to FIGS.
FIG. 12 shows a third embodiment of the standard specimen. Moreover, FIG. 13 is a figure which shows the image which image | photographed the state which the fluorescent magnetic powder adhering to the 3rd standard test body light-emitted with the imaging device. FIG. 14 is a block diagram showing a schematic configuration of a magnetic powder concentration measuring apparatus when it is desired to use the standard specimen according to the third embodiment. FIG. 15 is a flowchart showing a method of measuring the magnetic powder concentration when it is desired to use the standard test specimen according to the third embodiment.

  The third standard test body 30 shown in FIG. 12 is defined by the JIS standard in the same manner as the standard test body 20 according to the second embodiment described above, and specifically, JIS Z 2320. -2 test body defined by -2. The third standard test body 30 is formed in a substantially rectangular parallelepiped shape. Magnets 33 are provided at both ends of the third standard specimen 30 in the longitudinal direction. A gap 34 and a scale 35 that are defective portions are provided on one surface of the third standard specimen 30 that acts as a pseudo-defect portion.

  The gap 34 is a groove formed in a straight line along the longitudinal direction of one surface of the third standard specimen 30. This gap 34 is provided between two magnets 33, 33 on one surface of the third standard specimen 30. The fluorescent magnetic powder of the fluorescent magnetic powder liquid starts to adhere to the gap 34 from both ends of the gap 34, and the amount of the fluorescent magnetic powder attached decreases toward the center.

  Here, FIG. 13A shows a magnetic powder concentration of 0.1 g / l, FIG. 13B shows a magnetic powder concentration of 0.3 g / l, FIG. 13C shows a magnetic powder concentration of 0.5 g / l, and FIG. 13D shows a magnetic powder concentration of 1 g / l. FIG. 13E is an image taken by the CCD camera 6 of the state in which the fluorescent magnetic powder at a magnetic powder concentration of 1.5 g / l emits light. As shown in FIG. 13, it can be seen that the longer the concentration of the fluorescent magnetic powder, the longer the length of the fluorescent magnetic powder attached to the gap 34.

  As shown in FIG. 14, the processing unit 7bA of the personal computer 7A when using the standard specimen according to the third embodiment includes a luminance value calculation unit 71A, a length measurement unit 75A, and a magnetic powder concentration conversion. It has a portion 72A. The length measuring unit 75A performs a process of measuring the length of the fluorescent magnetic powder attached to the gap 34 based on the luminance value calculated by the luminance value calculating unit 71A. Specifically, a threshold value is set in advance for the luminance value (brightness and darkness), and a place that is brighter than this threshold value is detected. Then, the length from one end of the gap 34 to the place where the fluorescent magnetic powder is interrupted (a place darker than the threshold value) is measured. The magnetic powder concentration conversion unit 72A performs a process of converting the magnetic powder concentration from the length side-aided by the length measurement unit 75A.

  The memory 8A stores length-magnetic particle concentration conversion data 81A indicating the relationship between the magnetic particle concentration and the length. Then, based on the length-magnetic particle concentration conversion data 81A stored in the memory 8A, the magnetic particle concentration conversion unit 72A of the personal computer 7A converts the length into the magnetic particle concentration, whereby the magnetic particle concentration of the fluorescent magnetic powder liquid is converted. Is measured.

  Next, with reference to FIG. 14 and FIG. 15, a method for measuring the magnetic powder concentration when the third standard specimen 30 is desired to be described.

  First, the fluorescent magnetic powder is applied to one surface of the standard test body 30, and the fluorescent magnetic powder is adhered to the gap (pseudo defect portion) 34 (step S1A). At this time, the standard test body 30 is installed to be inclined in a direction of a predetermined angle (for example, about 45 degrees) from the horizontal plane so that the surface on which the scale 35 of the standard test body 30 is provided is vertical. And the fluorescent magnetic powder liquid is apply | coated to the standard test body 30 in the inclined state. Thereby, the excess fluorescent magnetic powder liquid flows down from one surface of the standard test body 30.

  Here, the inclination angle of the standard specimen 30 is set to the same angle as when the length-magnetic particle concentration conversion data 81A is created. In the first and second standard test bodies 2 and 20 described above, one surface of the standard test body may be inclined with respect to the horizontal plane in order to remove excess fluorescent magnetic powder liquid. Needless to say.

  Next, the standard test body 30 to which the fluorescent magnetic powder of the fluorescent magnetic powder is attached is placed at a predetermined position in the dark room 1. Then, the standard test body 30 is irradiated with ultraviolet light using the black light 5 (step S2A). Then, the fluorescent magnetic powder adhering to the gap 34 emits light. Next, the gap 34 irradiated with the ultraviolet light is photographed by the CCD camera 6 (step S3A). The image signal captured by the CCD camera 6 is supplied to the personal computer 7A.

  Next, the processing unit 7bA of the personal computer 7A calculates the luminance value from the image signal by the luminance value calculating unit 71A (step S4A). Then, the processing unit 7b of the personal computer 7 measures the length of the fluorescent magnetic powder from the luminance value by the length measuring unit 75A (step S5A).

  Next, the processing unit 7bA of the personal computer 7A converts the measured length into the magnetic powder concentration by the magnetic powder concentration conversion unit 72A (step S6A). That is, the processing unit 7bA calls the length-magnetic particle concentration conversion data 81A stored in the memory 8A. Then, the processing unit 7bA uses the magnetic particle concentration conversion unit 72A to check the length with the length-magnetic particle concentration conversion data 81A and convert the length into the magnetic particle concentration of the fluorescent magnetic powder liquid. Thereby, the measurement of the magnetic powder concentration of the fluorescent magnetic powder liquid whose magnetic powder concentration is unknown is completed.

  Other configurations are the same as those in the case where the standard specimen 2 according to the first embodiment is used, and thus description thereof is omitted. Even when the standard test specimen 30 having such a configuration is used, the same effects as those obtained when the standard test specimen 30 according to the first embodiment described above is used can be obtained.

  According to the magnetic powder concentration measuring apparatus and the magnetic powder concentration measuring method of the present invention, the magnetic powder concentration is determined from the luminance value by measuring the luminance value or the data indicating the relationship between the length of the fluorescent magnetic powder attached to the test body and the magnetic powder concentration in advance. It can be measured quantitatively. Thereby, a magnetic powder density | concentration can be measured correctly and rapidly, without producing a difference by the person who test | inspects.

  The present invention is not limited to the embodiment described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention described in the claims.

  In the above-described embodiment, the example in which the ultraviolet irradiation intensity of the black light that is the ultraviolet irradiation unit is controlled to be constant has been described. However, as the black light continues to be used, the ultraviolet irradiation intensity deteriorates. Therefore, when the black light deteriorates, the light source may be exchanged in order to keep the ultraviolet irradiation intensity constant. Further, the ultraviolet irradiation intensity of the black light is measured before measuring the magnetic powder concentration. Then, it goes without saying that the processing unit may calculate the luminance value of the fluorescent magnetic powder in accordance with the deterioration of the ultraviolet irradiation intensity.

1 shows a configuration of a magnetic powder concentration measuring apparatus according to an embodiment of the present invention. It is a perspective view which shows the 1st Embodiment of the standard test body which concerns on the magnetic powder density | concentration measuring apparatus of this invention. It is a block diagram which shows schematic structure of the magnetic powder density | concentration measuring apparatus of this invention. It is a figure which shows the state which immersed the standard test body in the fluorescent magnetic powder liquid. It is a graph which shows the relationship between a luminance value and a magnetic powder density | concentration. It is a flowchart which shows the magnetic powder density | concentration measuring method of this invention. The example of the screen displayed on the display part in the measurement part which concerns on the magnetic powder density | concentration measuring apparatus of this invention is shown. It is a graph which shows the relationship between the luminance value and magnetic powder density | concentration in several fluorescent magnetic powder from which a kind differs. It is a perspective view which shows the 2nd Embodiment of the standard test body which concerns on the magnetic powder density | concentration measuring apparatus of this invention. It is a top view which shows 2nd Embodiment of the standard test body which concerns on the magnetic-particle density | concentration measuring apparatus of this invention. It is a figure which shows the image which image | photographed the state which the fluorescent magnetic powder adhering to the 2nd standard test body light-emitted with the imaging device. It is a perspective view which shows the 3rd Embodiment of the standard test body which concerns on the magnetic powder density | concentration measuring apparatus of this invention. It is a figure which shows the image which image | photographed the state which the fluorescent magnetic powder adhering to the 2nd standard test body light-emitted with the imaging device. It is a block diagram which shows schematic structure of the magnetic-particle density | concentration measuring apparatus in the case of using the standard test body which concerns on the example of 3rd Embodiment. It is a flowchart which shows the measuring method of the magnetic-powder density | concentration in the case of using the standard test body which concerns on the example of 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Dark room, 2, 20, 30 ... Standard test body, 3,33 ... Magnet, 4a ... Pseudo defect part, 5 ... Black light (ultraviolet irradiation part), 6 ... CCD camera (imaging device), 7, 7A ... Personal Computer (measurement unit), 7a ... display unit, 7b, 7bA ... processing unit, 8 ... memory (storage unit), 10 ... magnetic powder bath, 34 ... gap, 71, 71A ... luminance value calculation unit, 72, 72A DESCRIPTION OF SYMBOLS ... Magnetic powder density | concentration conversion part, 75 ... Length measurement part, 81 ... Luminance value-magnetic powder density | concentration conversion data, 81A ... Length-magnetic powder density | concentration conversion data, 100 ... Magnetic powder density | concentration measuring apparatus

Claims (7)

A standard test specimen having a pseudo-defect portion on one side where the fluorescent magnetic powder of the fluorescent magnetic powder adheres by the magnetic pole;
Irradiating the standard test specimen to which the fluorescent magnetic powder is attached with ultraviolet light, and an ultraviolet irradiation section for emitting the fluorescent magnetic powder;
An imaging device for capturing an image signal by imaging the standard specimen irradiated with ultraviolet rays;
A processing unit that calculates a luminance value of the fluorescent magnetic powder emitted from the image signal and converts the luminance value into a magnetic powder concentration;
A magnetic powder concentration measuring apparatus comprising: A storage unit connected to the processing unit so as to be able to transmit and receive, and storing data indicating a relationship between the magnetic powder concentration and the luminance value;
The magnetic particle concentration measuring apparatus according to claim 1, wherein the processing unit converts the luminance value into a magnetic particle concentration based on the data stored in the storage unit. The processor is
The magnetic powder concentration measuring device according to claim 1, wherein the length of the fluorescent magnetic powder adhering to the pseudo defect portion is measured from the luminance value, and the length of the fluorescent magnetic powder is converted into a magnetic powder concentration. . A dark room in which the standard specimen, the ultraviolet irradiation unit, and the imaging device are disposed;
The magnetic particle concentration measuring apparatus according to claim 1, wherein the standard specimen is irradiated with ultraviolet light in the dark room and the standard specimen is photographed. The said standard test body is a test body defined by JISZ2320-2 of JIS specification. The magnetic particle concentration measuring apparatus in any one of Claims 1-4 characterized by the above-mentioned. It has a display part which displays the measured said magnetic-powder density | concentration. The magnetic-powder density | concentration measuring apparatus in any one of Claims 1-5 characterized by the above-mentioned. A step of attaching the fluorescent magnetic powder of the fluorescent magnetic powder liquid to the pseudo-defect portion provided on one surface of the standard specimen by a magnetic pole;
Irradiating the standard specimen to which the fluorescent magnetic powder is adhered with ultraviolet light, and causing the fluorescent magnetic powder to emit light;
Photographing the standard specimen irradiated with the ultraviolet light to obtain an image signal;
Calculating the luminance value of the fluorescent magnetic powder emitted from the image signal and converting the calculated luminance value into a magnetic powder concentration;
A magnetic powder concentration measuring method comprising: