JP2009168517A - Magnetic field visualizing apparatus, inspecting apparatus, visualizing method and defect detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visualizing apparatus capable of displaying a magnetic field distribution so as to be able to easily find a defect. <P>SOLUTION: The visualizing apparatus comprises a screen 21 having a first plane 1 and a second plane 2 comprising fluorescent materials 20 of a plurality of colors arranged in a certain order of colors; an electron beam irradiating means 23 irradiating an electron beam 22 to one of the fluorescent materials 20; a deflecting means 24 deflecting the electron beam 22; and a signal supplying means 26 providing a signal with the electron beam irradiating means 23 and the deflecting means 24, deflecting the electron beam 22 so as to irradiate only fluorescent materials 20 of one color among those of a polarity of colors, and displaying a color image only having that color on the screen 21. A color image having a plurality of colors that are corresponding with the magnetic field distribution is formed on the second plane by bringing the first plane close to the material while displaying the color image of that color and subjecting the electron beam 22 to Lorenz force. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a visualization device and a visualization method for a magnetic field distribution of a magnetic leaking material, and further relates to an inspection device and a defect detection method using the visualization device and the visualization method.

  Steel materials are used in power generation facilities and gas supply pipelines. If the steel materials are damaged or deteriorated, electricity and gas cannot be supplied, which has a serious impact on society. For example, in the medical field, if the supply of electricity or gas is stopped for a long time, there is even a life danger. For this reason, in order to prevent damage and deterioration of steel materials, quality inspection at the manufacturing stage and periodic inspection after installation are performed.

  In these inspections, nondestructive evaluation such as ultrasonic flaw detection is performed in order to detect a damaged part or a deteriorated part. This method is a method for evaluating damage and deterioration by cutting an internal state of an object by applying an ultrasonic wave to the object and visualizing the echo.

  Stainless steel is the most frequently used material among steel materials. This stainless steel exhibits paramagnetism, but martensite is generated and magnetized as the residual stress inside the material increases. Such a change from the initial condition of the material and deterioration of the material, that is, an increase in the lattice defect density from the solid material can be regarded as a change in magnetic properties.

  For example, changes in discontinuous magnetization (magnetic noise) that occur in the magnetization process and changes in the amount of local magnetization due to residual local lattice distortion can be detected as non-uniform magnetization distributions. It can be detected by nondestructive magnetic property evaluation.

  These magnetic noise changes and local changes in the amount of magnetization are measured using a magnetic sensor (Hall element) for measuring the strength and direction of the magnetic field (magnetic field), and measuring magnetic noise and magnetic flux density. Can be captured. In addition, the distance from the device to the sample surface can be obtained by a distance meter using a laser CCD, or the surface shape changes in the x, y, and z directions of the sample surface can be taken into the CCD by an interference reference mirror. A change in shape can also be captured (see Non-Patent Document 1).

  The magnetic field strength distribution can be visualized and displayed with high sensitivity by measuring the leakage magnetic flux density using a Hall element and measuring the surface shape using a laser CCD or interference reference mirror. Since it can be compared with the distribution after the passage, the change in the magnetization distribution and the change in the surface shape can be captured easily and with high sensitivity. From this, this method can easily evaluate damage and deterioration of a material with high sensitivity.

In addition, an apparatus capable of accurately and continuously visualizing and displaying the state of electromagnetic field radiation of the entire object to be measured has been proposed (see Patent Document 1). This device includes an antenna that detects an electric field or a magnetic field, a band filter that extracts a high-frequency voltage or high-frequency current induced in the antenna as an electric or magnetic field detection signal, and a signal level of the detection signal that is extracted by the band filter. A plurality of detection display units including display elements for visual display are arranged on a sheet. Specifically, the amount of heat corresponding to the signal level of the detection signal extracted by the bandpass filter is visualized by an infrared camera so that the spatial distribution state of the electric field can be observed. By installing this apparatus so as to cover the object to be measured, it is possible to accurately measure the electromagnetic field and directly display the state of the electromagnetic field at the position to be observed at that position.
Koji Yamada, Hitoshi Hirobe, “Non-destructive inspection of iron-based structural materials using magnetic sensors and surface shape measurement”, [online], 2000, [Searched on December 21, 2007], Internet <URL: http: //www.saitama-u.ac.jp/crc/professor/kiyo/h12/21.pdf> JP 2001-663337 A

  In leakage magnetic flux density measurement using a Hall element, the measurement accuracy is improved with a large number of samples by taking it into the CPU with a spatial resolution of 12 bits. In order to obtain an image of magnetic distribution, it takes a long time from several tens of minutes to several hours. Is needed.

  The apparatus using the antenna detects a magnetic field with the antenna, processes the detection signal, and displays an image. For this reason, it takes time to detect a magnetic field with an antenna, generate a detection signal, process the detection signal, and display an image, and a change in the magnetic field during that time cannot be observed. Even when a defect is discovered by magnetic field distribution, it takes time to detect the magnetic field with the antenna, generate a detection signal, process the detection signal, and display the image. I can't do it.

  In order to perform quality inspections in a flow operation and shorten the inspection time to improve the work efficiency, it is necessary to detect the presence or absence of defects in a short time. Also, in medical practice, there are cases where medical devices or damaged medical devices are left behind in the human body, and immediately detect whether the medical devices are left behind and whether or not the medical devices are damaged. It is hoped that it can be done.

  Therefore, it has been desired to provide a visualization apparatus and method that can immediately display the magnetic field distribution so that these defects can be easily found.

  As a result of intensive studies, the present inventor uses a cathode ray tube used in a color television, and displays the screen in one color of RGB while bringing the screen close to a material such as a metal that is magnetized and magnetically leaks. The charged particle of the electron beam receives the Lorentz force acting in the direction perpendicular to the traveling direction of the particle, hits the fluorescent material next to the target fluorescent material and further adjacent to the fluorescent material, and emits the electron beam From the electron gun side, the magnetic field distribution was clearly and immediately displayed in RGB. Since this magnetic field distribution is immediately displayed when the screen is brought close to the magnetic leaking material, the presence or absence of defects can be detected easily and in a short time.

  This invention is made | formed by discovering the above, The said subject can be solved by providing the visualization apparatus and visualization method of this invention.

According to the present invention, an apparatus for visualizing a magnetic field distribution of a magnetic leaking material,
A screen having a first surface disposed adjacent to the material, and a second surface comprising a plurality of color phosphors arranged in a certain color order on the back surface of the first surface;
An electron beam irradiation means for irradiating one of the fluorescent materials with an electron beam;
Deflection means for deflecting the electron beam irradiated from the electron beam irradiation means;
A signal is given to the electron beam irradiating means and the deflecting means, the deflecting is performed so that only the fluorescent material of one of the plurality of colors is irradiated with the electron beam, and the screen is made of only the color. Signal supply means for displaying a color image,
The first surface is brought close to the material while displaying the color image consisting only of the color, and the electron beam receives a Lorentz force according to the strength and direction of the magnetic field, thereby causing the second surface to A visualization device is provided that forms a color image composed of a plurality of colors corresponding to a magnetic field distribution.

  This visualization device includes a hollow body having an opening expanded on one side, and a screen is arranged at one end of the hollow body having the expanded opening so that the first surface faces outward and the second surface faces inside. The electron beam irradiation means is disposed at the other end, the deflection means is provided around the outer surface of the hollow body, and a window for visualizing the second surface is provided in a part of the hollow body. Can be. Thus, by covering with a hollow body, external light can be blocked, a clear color image can be displayed on the second surface, and the color image can be observed through a window.

  The visualization apparatus includes an imaging unit that is provided in the window and that captures the second surface, and a display unit that is connected to the imaging unit and displays a color image of the captured second surface. Can do. By displaying on the display means, the color image projected on the second surface can be appropriately enlarged and displayed, and a fine portion of the magnetic field distribution can be observed.

  In the present invention, the above-described visualization device, storage means for storing a color image corresponding to the magnetic field distribution of a material having no defect as reference data, and whether or not the color image obtained by the visualization device is different from the reference data are determined. It is also possible to provide an inspection apparatus for inspecting the quality of a material, which includes an image determination means for determining whether or not the image has a defect when different from the reference data.

  The defect is a flaw formed on the surface of the material, a cavity existing inside the material, or deformation due to stress, and the position and size of the defect are determined from the position and size of a portion different from the reference data.

  Furthermore, the present invention can provide a method for visualizing the magnetic field distribution of a magnetic leaking material and a method for detecting a defect in the material from the magnetic field distribution of the magnetic leaking material.

  By providing the magnetic field distribution visualization device of the present invention, the magnetic field distribution can be visually observed, and by providing an inspection device including the visualization device, defects such as steel materials can be removed without cutting or the like. It can be easily discovered destructively.

  Since this visualization device can clearly display the magnetic field distribution and easily understand the magnetic field distribution, it can be used as educational equipment for schools.

  Since this inspection apparatus and the method for detecting defects can be easily inspected non-destructively, the cost for quality inspection can be reduced and the inspection time can be shortened.

  In order to visualize the magnetic field distribution, that is, the strength and direction of the magnetic field, the material to be observed must be magnetized. Therefore, this material needs to be a substance that can be magnetized, and is a magnetic substance. The magnetic substance here is a ferromagnetic substance which is a substance that has the property of being extremely strongly magnetized in a magnetic field and leaving residual magnetization even when the magnetic field is removed. Examples of the ferromagnetic material include iron, cobalt, nickel, and the like.

  There are many products using iron, which is a ferromagnetic material, such as nuclear reactors, ships, gas pipes, water pipes, bolts and nuts. These products are easily magnetized, and there are coils, magnets, etc. through which current flows nearby. It is easily magnetized. Stainless steel, which is used in many cases as a steel material, is martensitic and magnetized as the internal residual stress increases. These magnetized materials leak magnetically and generate a magnetic field around them.

  In the manufacturing stage, these materials may have defects such as holes and scratches on the surface. This defect is also caused by using these materials. When such a defect occurs, the magnetic field generated around the defect also changes. Description will be made with reference to an iron rod 10 as shown in FIG. FIG. 1A shows magnetic lines of force when there is no flaw, and FIG. 1B shows magnetic lines of force when a flaw such as the groove 11 is formed at the center. When magnetized, a magnetic pole is generated. In FIG. 1, the N pole and the S pole are shown for easy understanding. As shown in FIG. 1 (a), when there is no flaw, the magnetic field lines are directed from the N pole at one end to the S pole at the other end. However, when the groove 11 exists as shown in FIG. A magnetic pole is generated at 11 and magnetic lines of force appearing from the N pole to the S pole generated at both ends of the groove 11 as shown in FIG. From this, it can be seen that the presence of a flaw changes the magnetic field distribution. This is not limited to scratches formed on the surface, and the same applies to defects such as holes existing inside. For this reason, the presence of a defect can be detected by acquiring a magnetic field distribution without defects in advance and detecting a different magnetic field distribution.

  If the presence or absence of this defect can be detected immediately, this quality inspection can be performed in a short time, and the cost can be reduced. In order to determine the presence or absence of defects in a short time, it is most efficient if the magnetic field distribution can be visualized.

  Therefore, the present invention provides a visualization device that can visually recognize the magnetic field distribution. This visualization device is a device that can instantly display the magnetic field distribution in a visible form simply by placing it in the vicinity of the magnetic leaking material. Since the magnetic field distribution is displayed immediately only by approaching the magnetic leaking material, the presence or absence of defects can be detected immediately. In addition, since it is possible to visually recognize the magnetic field distribution, it can be used as educational material for schools that are learning about magnetic fields. Can be given.

  With reference to FIG. 2, the structure of a visualization apparatus is demonstrated. The visualization device includes a screen 21 having a first surface and a second surface including a plurality of colors of fluorescent materials 20 arranged in a certain color order on the back surface of the first surface. Further, an electron beam irradiation unit 23 that irradiates one of the fluorescent materials 20 with an electron beam 22 and a deflection unit 24 that deflects the electron beam 22 irradiated from the electron beam irradiation unit 23 and displays a color image on the screen 21. With. Further, a mask 25 having a plurality of holes or a plurality of vertically long slits provided corresponding to each fluorescent material 20 is provided in order to accurately apply the electron beam 22 to the target fluorescent material 20. Further, a signal supply means 26 is provided for supplying a signal instructing the electron beam irradiation means 23 and the deflection means 24 to which color and in which position the fluorescent material 20 is to be irradiated with the electron beam 22.

  The second surface is coated with fluorescent materials 20 of respective colors in a matrix so as to be arranged in the order of red (R), green (G), blue (B), red, green, blue,. In the vertical line, fluorescent substances 20 of the same red, the same green, and the same blue are arranged at a predetermined interval, and adjacent colors are different, that is, red, green, and blue. For example, three electron beam irradiation means 23 can be provided for red, green, and blue, and the deflection means 24 deflects the electron beam 22 emitted from the electron beam irradiation means 23 and is applied to the second surface. Move the place to display one still image per tens of seconds. Although the location irradiated by the electron beam irradiation means 23 is one point at each moment, the irradiation time at each point is short, and it seems that each point of the entire screen 21 is irradiated simultaneously by the afterimage. Such a still image can be displayed.

  In this visualization apparatus, the deflecting unit 24 deflects the electron beam 22 so that only one of the RGB colors, for example, the blue fluorescent material 20 is irradiated, and causes the screen 21 to display a color image composed of only blue. After that, the first surface is brought close to the magnetic leaking material while displaying a color image consisting only of blue, and the electron beam 22 receives the Lorentz force, whereby a color image composed of RGB corresponding to the magnetic field distribution is formed on the second surface. Let it form. The color image formed on the second surface corresponds to the magnetic field distribution, and the magnetic field distribution of leakage magnetism generated around the material can be grasped only by looking at it.

  The magnetically leaking material is a ferromagnetic material such as a magnetized steel material, and a magnetic field is generated around it to form a magnetic field environment. When a magnetized ferromagnet is brought close to a charged particle flowing at a certain speed in a certain direction and the charged particle is placed in a magnetic field, the traveling direction is changed by receiving a force from the magnetic field. A force acting perpendicularly to the traveling direction that changes the traveling direction of the charged particles is a Lorentz force, and the charged particles receive the Lorentz force in a magnetic field. A charged particle is a charged particle, and includes ionized atoms, helium nuclei generated by nuclear decay, that is, alpha particles and electrons.

  The Lorentz force will be described in detail with reference to FIG. Prior to approaching the magnetized material, the electron beam 22 is not in a magnetic field environment and Lorentz force does not act. However, when the magnetized material is approached, the electron beam 22 is placed in the magnetic field environment by the magnetic field generated around the material, and the charged particles constituting the electron beam 22 are subjected to Lorentz force.

  When the direction in which the electron beam 22 travels is the direction of the arrow A toward the second surface 30 of the screen 21, and the N pole of the magnet 32 approaches the first surface 31 of the screen 21 facing the electron beam 22, The magnetic field is generated in the four directions of the screen 21. For example, the Lorentz force for the magnetic field indicated by the arrow B1 pointing upward in the vertical direction follows the Fleming's law, and the Lorentz force for the magnetic field indicated by the arrow C1 in the horizontal direction and the arrow B2 pointing downward is indicated by the arrow C2. As shown, it acts in the opposite direction to the arrow C1. Further, the Lorentz force with respect to the magnetic field directed in the horizontal direction acts upward or downward in the vertical direction.

  The fluorescent materials 20 are arranged in the order of red, green, blue,... In the horizontal direction on the side irradiated with the electron beam 22, and are the same red, the same green, or the same blue in the vertical direction. When the Lorentz force acts, it strikes the fluorescent material 20 of the adjacent color and develops that color against the magnetic field oriented in the vertical direction. On the other hand, since the Lorentz force acting in the vertical direction is the same color as that originally hit, the color does not change with respect to the magnetic field directed in the horizontal direction.

  For this reason, when the screen 21 is displayed in blue on the entire surface and the N pole of the magnet 32 is brought close to the first surface 31, the vertically upward magnetic field, that is, the upper side of the magnet 32, as shown in FIG. In response to the force, the electron beam 22 strikes the red fluorescent material 20 arranged on the right side of the blue as viewed from the side irradiated with the electron beam, and develops a red color indicated by R. Below the magnet 32, the electron beam 22 hits the green fluorescent material 20 arranged on the opposite side and develops a green color indicated by G. Since the left and right screens 21 with respect to the magnet 32 do not change in color, the left and right screens 21 develop blue in the same color as the original color. In FIG. 4, in addition to these colors, a vortex pattern is shown, which is a display of a vertically long slit of a shadow mask used as the mask 25.

  When the south pole of the magnet 32 is brought close to the screen 21, the upper side becomes green and the lower side becomes red, as shown in FIG. 4 (b). This is because the direction in which the Lorentz force acts is opposite.

  When the U-shaped magnet is brought closer, the direction of the magnetic field is one direction from the N pole to the S pole of the U-shaped magnet. For example, when the S pole is placed on the upper side and the N pole is placed on the lower side, a magnetic field is generated upward, and the portion between the S pole and the N pole is colored red as shown in FIG. On the other hand, when the N pole is placed on the upper side and the S pole is placed on the lower side, a magnetic field is generated downward, and the portion between the N and S poles is green as shown in FIG. Color develops.

Before receiving the Lorentz force, the electron beam 22 is applied only to the blue fluorescent material 20, but by receiving the Lorentz force, the red fluorescent material adjacent to the blue fluorescent material and the red fluorescent material adjacent to the red fluorescent material. Hits the green fluorescent material in This changes depending on the magnitude of the Lorentz force, and changes as shown in FIGS. 5A to 5C as the magnitude increases. 5A shows a weak magnetic field of less than 10 ⁻³ Tesla (10 Gauss), FIG. 5B shows a magnetic field of 0.6 Tesla, and FIG. 5C shows a magnetic field of 1.2 Tesla. Show the case. In FIG. 5, a current is passed through the coil to generate a magnetic field of each strength.

  In either case, the electron beam 22 is irradiated toward the blue fluorescent material. However, in FIG. 5A, the electron beam 22 placed in the magnetic field environment hits the red fluorescent material and is colored red. In FIG. 5B, since the magnetic field is stronger than in the case shown in FIG. 5A, a large Lorentz force acts. Since the Lorentz force is large on the side close to the magnetic leaking material on the screen 21 and decreases with distance from the material, a color image composed of RGB is displayed according to the size of the fluorescent material of red, green, and blue. The This color image expresses the strength and direction by the number and spacing of colors repeated in RGB, and the magnetic field is directed in the direction where the spacing is narrow like a contour line, and the strength of the magnetic field increases as the number of colors increases. Represents.

  Therefore, in FIG. 5C, since the magnetic field is stronger than in the case shown in FIG. 5B, a larger Lorentz force acts, and RGB in comparison with the case shown in FIG. The interval between is narrow and is expressed in many colors.

  As an apparatus including the screen 21, the electron beam irradiation means 23, the deflection means 24, and the mask 25, a cathode ray tube used in a color television can be exemplified. Most of these CRTs have a resolution of 640 x 480, take out the color signals of the three primary colors red, green, and blue from radio waves, and respond to the intensity of each color from the three electron guns of red, green, and blue The screen shines by emitting an electron beam and applying it to a screen that is finely coated with fluorescent materials that glow in red, green, and blue. On this screen, only one point is shining at each moment, and a stationary image is drawn in about 1/30 second by moving the place where the electron beam is applied. The color is changed depending on the intensity of the electron beam, and a magnetic field generated by two sets of coils is used to move the place where the electron beam is applied.

  A shadow mask is placed between the screen and the electron gun to shine one point accurately at each moment. The shadow mask is a metal plate having a large number of fine holes formed in a honeycomb shape, and an electron beam emitted from an electron gun is applied to a screen of a desired color applied to the screen through the many holes of the metal plate. A desired color is developed by applying to a fluorescent material. As the two sets of coils, electromagnetic coils called deflection yokes are used so that the electron beam emitted from the electron gun can be bent and applied to the fluorescent material of each color of the screen. The cathode ray tube is covered with a hollow body having one end expanded to block outside light and display a clear color image on the second surface.

  Instead of a cathode ray tube, an aperture grill tube that uses a shadow mask having a vertically long slit instead of a round hole shadow mask may be employed.

  In the visualization apparatus of the present invention, for example, the signal supply unit 26 outputs a signal so that only the blue fluorescent material 20 is irradiated with the electron beam 22, and the electron beam irradiation unit 23 and the deflection unit 24 receive the signal, Only the fluorescent material 20 is irradiated with the electron beam 22, and the screen 21 is displayed in blue, and close to the magnetically leaking material. When the hollow body 60 formed of the insulating material shown in FIG. 6A is provided to block outside light, a window 61 is formed in a part of the hollow body 60 as shown in FIG. The color image displayed on the second surface facing the inside of the hollow body 60 through the window 61 can be observed.

  The signal supply means 26 receives an input of a color preset by the user or a color selected by the user, generates a signal so that the color of the entire screen 21 becomes the input color, and outputs the signal to the electronic It supplies to the beam irradiation means 23 and the deflection means 24. When an electron beam irradiation means for each color is provided, the signal is supplied only to the electron beam irradiation means for that color. In order to generate the signal, it may be configured to include a memory in which a program for generating the signal is recorded, and a processor that reads the program from the memory and executes the program.

  Moreover, the window 61 provided in the hollow body 60 can be formed at a position and a size where the entire magnetic field distribution can be seen. The window 61 may be simply cut into a rectangle or a circle, but a door that can be opened and closed may be attached, or a transparent glass or the like may be fitted.

  Further, the window 61 may be provided with an imaging unit, and a display unit may be connected to the imaging unit. As the imaging means, a CCD camera can be mentioned, and as the display means, a monitor can be mentioned. As a result, the color image formed on the second surface can be enlarged and the color image can be displayed more clearly and clearly.

In addition, the imaging unit and the display unit can include a wireless communication unit that enables wireless communication, and the color image can be displayed even when the imaging unit and the display unit are separated by wireless communication. . The output from the imaging means is image data, and a storage means for storing the image data can be provided. The magnetic field sensitivity of the visualization device depends on the size of the fluorescent material 20 applied to the screen 21 and the hole diameter and pitch of the shadow mask used correspondingly, but a general cathode ray tube is used as the visualization device. Even in such a case, the magnetic field can be detected with a high sensitivity of about 2 × 10 ⁻⁶ Tesla (0.02 Gauss). Incidentally, the geomagnetism is about 0.3 to 0.5 gauss, and the leakage magnetism generated by the electronic equipment is 0.1 gauss or more.

  The present invention can also provide a magnetic field visualization method. This visualization method can be performed using the above-described visualization apparatus, and includes a first surface and a second surface including a plurality of colors of fluorescent materials arranged in a predetermined color order on the back surface of the first surface. A step of deflecting an electron beam so that only one fluorescent substance of a color of the screen is irradiated with an electron beam, and displaying a color image consisting only of the color on the screen, and displaying the color image consisting only of the color. Forming a color image composed of a plurality of colors corresponding to the magnetic field distribution on the second surface by causing one surface to approach the material and the electron beam receiving a Lorentz force according to the strength and direction of the magnetic field.

  Furthermore, in this invention, the quality inspection apparatus containing said visualization apparatus can be provided. This device includes the above-described visualization device, storage means for storing a color image corresponding to the magnetic field distribution of a material having no defect as reference data, and whether or not the color image obtained by the visualization device is different from the reference data. Image determining means for determining. The image determination unit determines that there is a defect when the reference data is different from the reference data stored in the storage unit.

  As a storage means, as long as data can be stored, in addition to memory and HDD, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-R, DVD-RW, DVD-RAM SD card etc. can be mentioned. A processor configured as the signal supply means 26 can be used to store the data. Note that a memory configured as the signal supply means 26 can also be used as the storage means.

  The image determination unit reads the reference data from the storage unit, executes a program for determination, and determines whether the image data of the obtained color image is different from the reference data. If it is determined that they are different, it is determined that they have a defect, and if they are determined to be the same, it is determined that there is no defect. Similar to the signal supply unit 26, the image determination unit realizes its function by executing a program, and therefore includes a memory for storing the program and a processor for reading and executing the program. it can.

  Defects are scratches formed on the surface of the material, cavities existing inside the material, deformation due to stress due to use, etc. The position and size of the defect from the position and size of the part different from the reference data Can be judged. Further, it can be seen from the magnetic field distribution whether the magnetic field gradient is steep or gentle, and it can be determined whether the damage is deep or shallow. In addition, when there is no damage | wound on the surface, it turns out that a cavity exists inside.

  In the above, image data of a material having no defect is stored in advance, and the image judging means compares it with the image data. However, the inspector can judge the presence or absence of a defect, and the image can be viewed. If the type and size of the defect can be determined simply by using only the above-described visualization device, the storage unit and the image determination unit may not be provided.

  Here, as a material, an image obtained by observing the leakage magnetism when a bar-shaped steel material magnetized with a magnetic field strength of 1 kOe (Oersted) is applied many times with a Hall element as a magnetic sensor, and 7 and 8 show images observed with the visualization apparatus having the above-described configuration. Note that 1 Oe is the strength of the magnetic field at a location 1 cm away from the unit magnetic pole in vacuum. FIG. 7 is an image when observed with a Hall element, and FIG. 8 is an image when observed with a visualization device. FIG. 7A shows the magnetic flux distribution of leakage magnetism, and FIG. 7B shows the leakage flux first derivative distribution obtained by differentiating the magnetic flux Φ by the distance x. FIG. 8A shows the magnetic flux distribution of leakage magnetism as in FIG. 7A, and FIG. 8B shows the first derivative distribution of leakage magnetic flux as in FIG. 7B.

  The image shown in FIG. 7 is an image acquired by the Hall element, and it took about 1 hour to acquire this image. Referring to the image shown in FIG. 7 (a), one end is magnetized to, for example, the N pole and the other end is magnetized to the S pole and is shown in red and blue, and both ends having a high magnetic flux density are dark and the magnetic flux density is low. As they go to the center, their colors fade. Referring to the image shown in FIG. 7 (b), most of the steel material is shown in blue, and there are a plurality of spots shown in red in it, and the lattice defect density generated by applying stress repeatedly many times. The distribution could be observed by the spots.

  The image shown in FIG. 8 is an image acquired in a few seconds by the visualization apparatus shown in FIG. In this case, the image shown in FIG. 8A is almost the same as the image shown in FIG. 7A, and one end is magnetized to, for example, the N pole and the other end is magnetized to the S pole. Both ends of the high density are dark in color, and the colors become lighter toward the central part where the magnetic flux density is low. In FIG. 8B, the steel material is shown in black, and the lattice defect density distribution shown in a mosaic pattern in red and blue can be clearly observed therein. From this, it was found that a high-sensitivity image can be acquired in a short time and defects can be detected with high accuracy compared to the case of using a Hall element.

  FIG. 9 is a diagram showing the thickness (mm) in the length direction of the steel material and the noise peak position (rel). The thickness is reduced at a position of about 20 to 40 mm and a position of about 80 mm, and the noise peak position is correspondingly increased. This corresponds to the portion where the spots shown in FIG. 7B are dense, and the portion shown in mosaic in red and blue shown in FIG. 8B. From this, it was found that a portion where the material thickness is thin due to deformation due to stress can be detected with high accuracy.

  A Kocher hemostatic forceps is a medical instrument that stops blood flow during surgery. The Kochel hemostatic forceps is shown in FIG. This Kochel hemostatic forceps is manufactured from stainless steel, and includes a high-rigidity portion 110 having a grip portion 100 in which peaks and valleys are continuous, a flexible portion 120 continuous with the high-rigidity portion 110, and a flexible portion 120, Two forceps members having an insertion part 130 for inserting a finger are rotatably supported by a support part 140 attached between the high-rigidity part 110 and the flexible part 120. Like the scissors, this is used by putting a finger in each of the two insertion portions 130 and opening and closing the two fingers.

  In the finishing process of the Kochel hemostatic forceps, the grip portion 100 forms the surface by forging. Forging refers to forming a metal by hitting it with a hammer. For this reason, when the grip portion 100 is formed, a large stress is applied to the material, and the portion is magnetized. FIG. 11 shows a state in which the tip of the high-rigidity portion 110 including the grip portion 100 is brought close to the screen 21 of the visualization device and the magnetic field distribution is displayed on the screen 21. Since the tip is magnetized to the north pole, the upper side of the forceps is displayed in red and the lower side is displayed in green, as shown in FIG. Thus, in stainless steel, it is magnetized by applying stress, and the magnetic field distribution is displayed in the visualization device.

  The Kocher hemostatic forceps concentrates stress on the grip 100 even when used. For this reason, the grip portion 100 is easily damaged, and the fragments may be left behind in the human body during the operation. In order to prevent this from happening, it can be proposed to form the grip portion 100 by welding or the like so that stress is not applied as much as possible in the finishing stage. This proposal can be made by detecting a magnetized portion of the stainless steel that is stressed by a visualization device. For this reason, the visualization device is also useful for detecting a portion to which such stress is applied.

  So far, the magnetic field visualization device, visualization method, quality inspection device, and defect detection method of the present invention have been described with reference to the drawings, but the present invention is limited to the embodiments shown in the drawings. However, other embodiments, additions, changes, deletions, and the like can be changed within a range that can be conceived by those skilled in the art, and as long as the operations and effects of the present invention are exhibited in any aspect, the present invention It is included in the range.

  As described above, the magnetic field visualization apparatus and visualization method of the present invention are useful as teaching materials for understanding magnetic fields in school education. In other words, it has a great impact in the physical education field, and the relationship between the Lorentz force and the electron current, the absolute evaluation of the N pole and S pole of the magnet, etc. can be intuitively understood with RGB color sense. . In addition, the inspection device and the defect detection method enable the quality inspection of parts and products manufactured from magnetic materials to be performed in a flow operation, and can be performed at any location, so that mounting Useful for inspections in the back and in narrow places. Furthermore, by making the shadow mask finer and more sensitive, it becomes possible to find further minute defects.

  As shown in FIG. 5, this visualization device changes the displayed image according to the strength of the magnetic field, so that it can measure the strength of the magnetic field and can be applied to a non-contact ammeter. is there. This is because when a current is passed through an electric wire, a magnetic field is generated around the current, and the current and the strength of the magnetic field are in a proportional relationship, so that the current value can be measured if the visualization can measure the magnetic strength.

The figure which showed the magnetic force line of the magnetic field which generate | occur | produces around the magnetized iron rod. The figure which showed embodiment of the visualization apparatus of this invention. The figure which showed direction of the Lorentz force which an electron beam receives. The figure which made the screen the whole surface blue, and showed the place which brought the magnet close to the 1st surface. The figure which showed magnetic field distribution which changes with the magnitude | size of Lorentz force. The figure which illustrated the hollow body used for a visualization device. The figure which showed the image at the time of observing the leakage magnetism of the magnetized rod-shaped steel material with the Hall element which is a magnetic sensor. The figure which showed the image at the time of observing the leakage magnetism of the magnetized rod-shaped steel material with the visualization apparatus shown in FIG. The figure which showed the relationship between the length of steel materials, thickness, and a noise peak position. The figure which showed Kochel hemostatic forceps. The figure which showed the magnetic field distribution of the holding part of Kochel hemostatic forceps.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Rod, 11 ... Groove, 20 ... Fluorescent substance, 21 ... Screen, 22 ... Electron beam, 23 ... Electron beam irradiation means, 24 ... Deflection means, 25 ... Mask, 26 ... Signal supply means, 30 ... Second surface, DESCRIPTION OF SYMBOLS 31 ... 1st surface, 32 ... Magnet, 60 ... Hollow body, 61 ... Window, 100 ... Grab part, 110 ... High rigidity part, 120 ... Flexible part, 130 ... Insertion part, 140 ... Support part

Claims (9)

A device for visualizing the magnetic field distribution of magnetically leaking material,
A screen having a first surface disposed adjacent to the material, and a second surface comprising a plurality of color phosphors arranged in a certain color order on the back surface of the first surface;
An electron beam irradiation means for irradiating one of the fluorescent materials with an electron beam;
Deflection means for deflecting the electron beam irradiated from the electron beam irradiation means;
A signal that gives a signal to the electron beam irradiation means and the deflection means, deflects the electron beam so that only the fluorescent material of one of the plurality of colors is irradiated with the electron beam, and makes the screen include only the color. Signal supply means for displaying an image,
The first surface is brought close to the material while displaying the color image composed only of the color, and the electron beam receives a Lorentz force according to the strength and direction of the magnetic field, thereby causing the second surface to A visualization device for forming a color image composed of a plurality of colors corresponding to a magnetic field distribution.   One end of the hollow body includes an expanded hollow body, and the screen is disposed at one end of the hollow body having the expanded opening so that the first surface faces outward and the second surface faces internal. A window for visualizing the second surface in a part of the hollow body, wherein the electron beam irradiation means is disposed at the other end, and the deflecting means is provided around the outer surface of the hollow body. The visualization device according to claim 1, further comprising:   3. An imaging unit provided in the window and configured to image the second surface; and a display unit connected to the imaging unit and configured to display a captured color image of the second surface. The visualization device described in 1.   The visualization apparatus according to any one of claims 1 to 3, storage means for storing the color image corresponding to the magnetic field distribution of the material having no defect as reference data, and a color obtained by the visualization apparatus An inspection apparatus for inspecting the quality of the material, including image determining means for determining whether an image is different from the reference data, and determining that the image has a defect when different from the reference data.   The defect is a flaw formed on the surface of the material, a cavity existing inside the material, or deformation due to stress, and the position and size of the defect are determined from the position and size of a portion different from the reference data. The inspection apparatus according to claim 4. A method for visualizing a magnetic field distribution of a magnetic leaking material,
An electron beam is irradiated only to the fluorescent material of one color of a screen having a first surface and a second surface having a plurality of fluorescent materials arranged in a predetermined color order on the back surface of the first surface. And displaying a color image consisting only of the color on the screen;
The first surface is brought close to the material while displaying the color image composed only of the color, and the electron beam receives a Lorentz force according to the strength and direction of the magnetic field, thereby causing the second surface to Forming a color image composed of the plurality of colors corresponding to the magnetic field distribution.   The visualization method according to claim 6, further comprising: imaging the second surface; and displaying a captured color image of the second surface. A method for detecting defects in a material from a magnetic field distribution of the material that leaks magnetically,
An electron beam is irradiated only to the fluorescent material of one color of a screen having a first surface and a second surface having a plurality of fluorescent materials arranged in a predetermined color order on the back surface of the first surface. And displaying a color image consisting only of the color on the screen;
The first surface is brought close to the material while displaying the color image composed only of the color, and the electron beam receives a Lorentz force according to the strength and direction of the magnetic field, thereby causing the second surface to Forming a color image composed of the plurality of colors corresponding to a magnetic field distribution;
Reading the color image corresponding to the magnetic field distribution of the material free of defects stored as reference data in storage means;
And a step of determining whether or not the formed color image is different from the reference data, and determining a defect when the color image is different from the reference data. The defect is a flaw formed on the surface of the material, a cavity existing inside the material, or deformation due to stress, and the position and size of the defect are determined from the position and size of a portion different from the reference data. The defect detection method according to claim 8, further comprising a step of:

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