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WO2008072508A1 - Instrument d'essai non destructif et procédé d'essai non destructif - Google Patents

Instrument d'essai non destructif et procédé d'essai non destructif Download PDF

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Publication number
WO2008072508A1
WO2008072508A1 PCT/JP2007/073441 JP2007073441W WO2008072508A1 WO 2008072508 A1 WO2008072508 A1 WO 2008072508A1 JP 2007073441 W JP2007073441 W JP 2007073441W WO 2008072508 A1 WO2008072508 A1 WO 2008072508A1
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WIPO (PCT)
Prior art keywords
subject
magnetic
potential difference
nondestructive inspection
magnetic field
Prior art date
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Ceased
Application number
PCT/JP2007/073441
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English (en)
Japanese (ja)
Inventor
Kiyoshi Hashimoto
Yasumitsu Tomita
Naoki Osawa
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University of Osaka NUC
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Osaka University NUC
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Publication of WO2008072508A1 publication Critical patent/WO2008072508A1/fr
Anticipated expiration legal-status Critical
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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
    • G01N27/83—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws by investigating stray magnetic fields

Definitions

  • the present invention relates to a nondestructive inspection apparatus and a nondestructive inspection method using a magnetic potential difference.
  • a non-destructive testing apparatus that uses electrical characteristics that in principle requires an electric current to flow through a subject
  • a non-destructive testing apparatus that uses the magnetic characteristics of a subject uses a magnetic field. There is no need to bring the destructive inspection device into contact with the subject.
  • the magnetic properties of this specimen including measurement of residual stress due to magnetostriction, diagnosis of fatigue damage due to Barkhausen noise, and detection of flaws due to leakage magnetic flux.
  • a patent There is a magnetic flaw detector disclosed in Reference 1.
  • This magnetic flaw detector uses two magnetic sensors provided at the center position of the magnetizer and at a position away from the center position to detect leakage magnetic flux under strong magnetization conditions, and from these two magnetic sensors. By calculating these two signals, the noise component that is included in both of them is canceled, enabling defect detection with a good S / N ratio.
  • the cracks of the specimen include a surface crack and an internal crack, and the surface crack is divided into a near side crack existing on the inspection surface and a far side crack existing on the back surface.
  • the internal flaw and the far-side crack cannot be evaluated in the magnetic flaw inspection using the FEM.
  • Patent Document 1 Japanese Published Patent Publication “JP 2000-227419” (published on August 15, 2000)
  • Non-Patent Document 1 Hashimoto Seishi, Yasutaka Hamada, Naoki Osawa et al., “Study on non-destructive crack detection system using magnetic properties”, Proc. Of the Japan Shipbuilding Society, No. 4, pl31 — 132, November 25, 26, 2004
  • Non-Patent Document 2 Hashimoto Seishi, Yasuda Hamada, Naoki Osawa and others, “Study on crack damage detection system using non-destructive inspection using magnetic properties, Part 2 Application to welded joints”, Japan Marine Proceedings of Engineering Society Lecture, No. 1, November 24, 25, 2005
  • the present invention has been made in view of the above-described conventional problems. It is possible to detect a subject in a non-contact manner, remove the influence of lift-off, and remove a near side crack.
  • An object is to provide a nondestructive inspection apparatus that can stably evaluate a far-side crack and an internal crack at a relatively low cost in a short time, and can be reduced in size and weight.
  • a nondestructive inspection apparatus according to the present invention is a nondestructive inspection apparatus for inspecting a defect inside a subject to solve the above-described problem, and a transmission magnetic flux that passes through the inside of the subject.
  • the magnetic potential difference measuring means for measuring the magnetic potential difference between the two points from the outside of the subject and the subject and the magnetic potential difference measuring means are relatively moved, the magnetic field difference is measured. It is characterized by comprising defect detecting means for detecting the presence of a defect inside the subject by detecting a change in magnetic potential difference measured by the potential difference measuring means.
  • the nondestructive inspection method of the present invention is a nondestructive inspection method for inspecting a defect inside a subject using a nondestructive inspection apparatus in order to solve the above-mentioned problem.
  • a defect detection means provided in a nondestructive inspection apparatus detects a change in magnetic potential difference measured by the magnetic potential difference measurement means when the subject and the magnetic potential difference measurement means are relatively moved.
  • a defect detecting step for detecting the presence of a defect inside the subject.
  • the magnetic potential difference measuring unit measures the magnetic potential difference between two points of the transmitted magnetic flux transmitted through the inside of the subject from the outside of the subject. Then, when the specimen and the magnetic potential difference measuring means are relatively moved, a change in the magnetic potential difference measured by the magnetic potential difference measuring means is detected, whereby a defect inside the specimen is detected. Detect the presence of.
  • defects present at various positions inside the subject include various cracks such as surface cracks and internal cracks as well as various singularities of the specimen. Also, Surface cracks can be classified as so-called near-side cracks and far-side cracks.
  • any of near-side cracks, far-side cracks and internal cracks can be used. It is possible to evaluate.
  • the “near side crack” is a surface crack on the measurement surface side of the subject
  • the “far side crack” is a surface crack on the back side of the measurement surface of the subject.
  • An “internal crack” is a crack inside the subject.
  • the magnetic potential difference measuring means when the subject and the magnetic potential difference measuring means are relatively moved, only the change in the magnetic potential difference measured by the magnetic potential difference measuring means is detected. Since the presence of internal defects can be detected, it can be evaluated in a short time. In addition, in order to detect changes in the magnetic potential difference, it is not necessary to magnetically saturate the measurement site of the subject, and the device can be reduced in size and weight. In addition, the simple method of using the magnetic potential difference makes the circuit configuration simple and enables the creation of a non-destructive inspection device at low cost.
  • FIG. 1 is a block diagram showing a configuration of a nondestructive inspection apparatus according to the present invention.
  • FIG. 2 is a diagram showing a plurality of embodiments of the nondestructive inspection device, (a) shows an embodiment of the nondestructive inspection device, and (b) is a diagram of the nondestructive inspection device. Another embodiment is shown, and (c) shows still another embodiment of the nondestructive inspection apparatus.
  • FIG. 3 is a schematic diagram showing the state of magnetic flux flowing through the nondestructive inspection apparatus, (a) showing the state of magnetic flux flowing through the nondestructive inspection apparatus when there is no defect in the subject, and (b) The state of the magnetic flux which flows into the said nondestructive inspection apparatus when a subject has a defect is shown.
  • FIG. 4 is a diagram showing the measurement results when there is no defect in the specimen, (a) is the pickup core (B) shows the measurement result with the excitation core.
  • FIG. 5 is a diagram showing measurement results when there is a defect in the specimen.
  • (A) shows the measurement results with the pickup core, and (b) shows the measurement results with the excitation core.
  • FIG. 6 is a diagram showing a state when the magnetic flux of the exciting core is controlled to take a constant value.
  • FIG. 7 is a diagram showing the sensitivity of the nondestructive detection device when an alternating current is passed through the first coil and its frequency is changed.
  • FIG. 1 is a block diagram showing the configuration of the nondestructive inspection apparatus 20.
  • the nondestructive inspection apparatus 20 is an apparatus for inspecting a defect inside a subject. As shown in FIG.
  • the subject 7 is an object to be inspected by the nondestructive inspection apparatus 20, and is usually made of a magnetic material, but is not limited thereto, and is made of a material containing a magnetic material. If it is, it may be acceptable.
  • the microcomputer 1 controls the magnitude of the current or voltage generated by the signal generator 2 and the frequency in the case of AC in accordance with an instruction of an input unit (not shown), and is sent from the ⁇ / D converter 13. Various processes are performed, such as processing the incoming digital data and displaying the processing results on a display unit (not shown).
  • the microcomputer 1 may be anything as long as it includes a control unit, a calculation unit, and a memory, and is provided either inside or outside the nondestructive inspection apparatus 20. It may be a thing.
  • the signal generator 2 determines the type of direct current or alternating current, the magnitude of the current or voltage, the amplitude, frequency, waveform, etc. in the case of alternating current according to the instructions of the microcomputer 1, and determines the preamplifier. A current is passed through 3 or a voltage is applied.
  • the preamplifier 3 adds the current or voltage sent from the signal generator 2 and the first integrator 15, and amplifies the added current or voltage and sends it to the first power amplifier 4. is there.
  • the first power amplifier 4 amplifies the current or voltage sent from the preamplifier 3 and applies it to or flows through the first coil 5.
  • the first power amplifier 4 sends analog data of a voltage value given to the first coil 5 or a flowing current value to the A / D converter 13.
  • the first coil 5 generates a magnetic field inside the first coil 5 according to the current supplied from the first power amplifier 4 or flowing.
  • the exciting core 6 is for increasing the magnetic permeability inside the first coil 5 and strengthening the magnetic field generated inside the first coil 5 so as to be applied to the subject 7 as an external magnetic field.
  • a high magnetic permeability material such as amorphous ferrite or high magnetic permeability steel is preferable.
  • the pickup core 8 is for forming a magnetic path provided outside the subject by connecting two points of the transmitted magnetic flux that passes through the subject.
  • the fourth coil 9 gives an induced electromotive force to the second integrator 10 according to the change of the magnetic flux in the pick-up core 8.
  • the second integrator 10 sends the result of integrating the induced electromotive force given by the fourth coil 9 to the second power amplifier 11 as a current value or a voltage value.
  • the second power amplifier 11 amplifies the current or voltage sent from the second integrator 10 and sends it to the third coil 12 and the A / D converter 13.
  • the third coin 12 is a magnetic field opposite to the external magnetic field applied to the subject according to the current or voltage sent from the second power amplifier 11 (hereinafter referred to as "reverse magnetic field"). Is applied to prevent a part of the transmitted magnetic field from passing through the pickup core 8.
  • the A / D converter 13 converts the analog current value or voltage value obtained from the first power amplifier 4 and the second power amplifier 11 into digital data, and outputs it to the microcomputer 1 as a measured value. To send.
  • the second coil 14 provides the first integrator 15 with an induced conductive pressure corresponding to a change in the magnetic flux in the exciting core 6.
  • the first integrator 15 sends the result of integrating the induced electromotive force given by the second coil 14 to the preamplifier 3.
  • the amplification factors of the preamplifier 3, the first power amplifier 4, and the second partial amplifier 11 are the material, number of turns, and number of turns of the first coil 5, the second coinor 14, the third coinor 12, and the fourth coil 9, respectively.
  • an appropriate value may be set in advance according to the purpose.
  • the shape of the exciting core 6 is a donut shape.
  • the figure shows the case where the shape is divided into 1/2 and 1/4. Note that the shape of one of the parts divided into the shape force m / n (m ⁇ n, where m and n are integers equal to or greater than 1) of the exciting core 6 is adopted, without being limited to such a case. Is possible.
  • Fig. 2 (a) is an example of a configuration of the nondestructive inspection apparatus 20 used when the measurement site of the subject is planar.
  • the exciting core 6 has a donut shape that is cut in half along the axis of symmetry (divided in half).
  • Two parts of a substantially rectangular shape shown in the lower part of (a) of FIG. 2 are a part corresponding to a cut face of a doughnut-shaped shape. Since these two surfaces ⁇ and ⁇ are substantially on the same plane, when the subject 7 is planar, the excitation core 6 is easily brought into contact with the subject 7.
  • FIG. 2 (b) shows another example of the configuration of the nondestructive inspection apparatus 20 used for inspecting a defect when the subject has a shape bent at a right angle.
  • the excitation core 6 has a shape obtained by dividing a donut shape into quarters.
  • Two plane C 'D forces corresponding to the donut-shaped cut shown in the lower part of Fig. 2 (b) Compared to Fig. 2 (a), the plane is inclined obliquely.
  • the right side D is inclined 45 degrees upward as compared to the case of Fig. 2 (a).
  • Left face C is tilted 45 degrees to the left.
  • the angle between the planes including the left side C and the right side D is approximately 90 degrees, so the shape of the subject 7 is 90 degrees with respect to the flat plate.
  • the exciting core 6 can be easily brought into contact with the subject 7! /, And the structure becomes! /.
  • FIG. 2 (c) shows still another example of the configuration of the nondestructive inspection apparatus 20, and the shape thereof is the measuring section E force S and the roundness on the subject 7 in the excitation core 6. It has the characteristic of being tinged. Therefore, the measurement part E for the subject 7 in the excitation core 6 is rounded! /, So that the measurement of the excitation core can be performed on the subject 7 having various shapes without changing the shape of the nondestructive inspection device 20. The site can be contacted.
  • FIG. 1, FIG. 3 (a), FIG. 3 (b), FIG. 4 (a), FIG. 4 (b), FIG. 5 (a), FIG. 5 (b) Based on FIGS.
  • FIG. 3 (a) is a schematic diagram showing the state of magnetic flux flowing through the nondestructive inspection apparatus 20 when the subject 7 has no defect
  • Fig. 3 (b) shows the case where the subject 7 has a defect
  • 6 is a schematic view showing a state of magnetic flux flowing through the non-destructive inspection device 20 of a combination.
  • FIG. 3 (a) when there is no defect in the subject 7, there are a total of eight magnetic fluxes generated inside the subject 7 by the exciting core 6, and two of these are the pickup cores 8. It is transparent.
  • FIG. 3 (b) when the subject 7 has a defect, there are a total of eight magnetic fluxes generated in the subject 7 by the exciting core 6, and three of them are the pickup core 8. It is transparent.
  • the force that the excitation core 6 reduces the number of magnetic fluxes generated inside the object 7 by one and the number of magnetic fluxes that pass through the pickup core 8 increases by one. This shows that the magnetic resistance of the subject 7 has increased.
  • the magnetic potential difference between the two points of the transmitted magnetic flux passing through the inside of the subject 7 is present when there is a defect in the measurement site of the subject 7! N / A, it can be seen that the situation is different.
  • the nondestructive inspection apparatus 20 applies this principle.
  • the signal generator 2 supplies current or voltage to the preamplifier 3 according to the instruction from the micro computer 1.
  • This current or voltage may be direct current or alternating current.
  • the frequency of alternating current or voltage can be changed to use the skin effect (adjusting the depth of transmitted magnetic flux from the surface of the subject). It is possible to measure the crack depth from the surface of the test object 7. For example, for the skin effect, the depth s from the surface on the measurement surface side of the subject 7 where the magnetic flux density is approximately 37% of the surface portion is a function of the frequency ⁇ and is given by the following equation: ing.
  • p is the resistivity of the subject, and is the magnetic permeability of the subject.
  • the force S can be increased by increasing the frequency ⁇ to reduce the depth s and decreasing the frequency ⁇ to increase the depth s.
  • the amplitude of the alternating current or voltage is gradually increased after being gradually increased. Then, by applying a strong external magnetic field, the magnetization generated in the subject 7 can be removed, and the influence of the magnetization of the subject 7 can be reduced in the next measurement.
  • the current or voltage sent from the signal generator 2 is amplified by the preamplifier 3 and the first power amplifier 4 and sent to the first coil 5.
  • a magnetic field is generated in the first coil 5 in response to this current or voltage. That is, the strength of the generated magnetic field can be changed according to the current or voltage of the first coil 5.
  • the magnetic field generated in the first coil 5 is applied to the subject 7 as an external magnetic field because the magnetic permeability inside the first coil 5 is increased by the exciting core 6 and the strength thereof is increased.
  • the excitation core 6 is preferably configured using a material that increases the magnetic permeability inside the first coil 5, for example, a high permeability material such as amorphous ferrite or high permeability steel.
  • the magnetic flux inside the fourth coil 9 changes, and therefore an induced electromotive force is generated in the fourth coil 9 by electromagnetic induction.
  • the second integrator 10 integrates the induced electromotive force.
  • the result of the integration is amplified by the second power amplifier 11 and fed back to the third coil 12.
  • the third coil 12 generates a magnetic field (reverse magnetic field) opposite to the external magnetic field by this current or voltage.
  • the amplification factor of the second power amplifier 11 is set to an appropriate value, a reverse magnetic field can be applied so that part of the transmitted magnetic flux does not pass through the pickup core 8. At this time, the magnetic flux in the pickup core 8 becomes zero.
  • the magnitude of the current flowing through the third coil 12 when the magnetic flux in the pickup core 8 is 0 is two points of the transmitted magnetic flux that passes through the inside of the subject. It corresponds to the magnitude of the magnetic potential difference between the two.
  • the transmitted magnetic flux that passes through the inside of the subject is measured between two points.
  • the result is equivalent to measuring the magnetic potential difference.
  • the current value or voltage value of the analog data is converted into digital data by the A / D converter 13 and sent to the microcomputer 1 as a measured value.
  • the current value or voltage value is in accordance with the strength of the magnetic field of the reverse magnetic field, measuring the potential difference or voltage value between the two points of the transmitted magnetic flux passing through the inside of the subject. It is possible to measure the amount corresponding to the magnetic potential difference. Therefore, it is equivalent to detecting the magnetic potential difference between two points of the transmitted magnetic flux passing through the inside of the subject. Further, when the subject 7 and the magnetic potential difference measuring means are relatively moved, by detecting a change in the magnetic potential difference measured by the magnetic potential difference measuring means, defects inside the subject 7 can be detected. Can detect presence
  • the external magnetic field applied to the subject 7 by the excitation core 6 decreases as the distance between the excitation core 6 and the subject 7 increases. In other words, if more accurate measurements are to be made, it is necessary to remove the effects of lift-off as much as possible.
  • the second coil 14 and the first integrator 15 are provided to eliminate the influence of the lift-off as much as possible. As the distance between the excitation core 6 and the subject 7 increases, the magnetic flux of the excitation core 6 changes accordingly. Then, an induced electromotive force is generated in the second coil 14 due to the change of the magnetic flux. This induced electromotive force is integrated by the first integrator 15 and sent to the preamplifier 3. According to the law of electromagnetic induction, the second coil 14 is induced according to the change of magnetic flux in the exciting core 6. An electromotive force is generated.
  • the magnetic flux in the exciting core 6 can be kept constant. That is, the external magnetic field that generates the transmitted magnetic flux from the outside of the subject 7 can be kept constant. Therefore, in the nondestructive inspection apparatus 20, the influence of lift-off due to the change in the distance between the nondestructive inspection apparatus 20 and the subject 7 can be removed.
  • the nondestructive inspection apparatus 20 uses the magnetic field property to inspect using the magnetic field difference between two points of the transmitted magnetic flux that passes through the inside of the subject 7, and thus is nondestructive. There is no need to bring the inspection device 20 into contact with the subject 7. Also, when inspecting using a magnetic potential difference, it is only necessary to consider the magnetic resistance between two points of the transmitted magnetic flux that passes through the inside of the subject 7, so that the distance between the nondestructive inspection device 20 and the subject 7 is small. It is possible to remove the effects of lift-off caused by changes. For this reason, it is possible to stably evaluate defects existing in the specimen 7.
  • near-side cracks, far-side cracks and internal cracks can be evaluated by transmitting the transmitted magnetic flux deep from the surface of the subject 7.
  • the “near-side crack” is a surface crack on the measurement surface side of the subject 7
  • the “far-side crack” is a surface crack on the back side of the measurement surface of the subject 7.
  • the “internal crack” is a crack inside the subject 7.
  • the inside of the subject 7 is detected only by detecting a change in the magnetic potential difference measured by the magnetic potential difference measuring means. Because the presence of defects can be detected, the specimen can be evaluated in a short time. Then, in order to detect a change in magnetic potential difference, it is not necessary to magnetically saturate the measurement site of the subject 7, and the nondestructive inspection apparatus 20 can be reduced in size and weight. Furthermore, since the simple method of using the magnetic potential difference is used, the circuit configuration is simple, and the nondestructive inspection apparatus 20 can be created at low cost.
  • FIG. 4 (a) is a diagram showing the measurement result of the pickup core 8 when the subject 7 has no defect
  • Fig. 4 (b) shows the excitation when the subject 7 has no defect
  • FIG. 6 is a diagram showing the measurement results of core 6.
  • (a) in FIG. 5 is a diagram showing the measurement results of the pickup core when there is a defect in the object
  • (b) in FIG. 5 is the excitation core when there is a defect in the object.
  • FIG. 5 is the excitation core when there is a defect in the object.
  • FIG. 5 is the excitation core when there is a defect in the object.
  • FIG. 5 is the excitation core when there is a defect in the object.
  • FIG. 5 It is a figure which shows a measurement result.
  • these figures are graphed as changes in magnetic flux in the excitation core 6 and the pickup core 8 rather than changes in the magnetic potential difference. Time on the horizontal axis indicates time, and Flax on the vertical axis indicates magnetic flux.
  • FIG. 4 (a) and FIG. 5 (a) are compared, there is a marked difference in the measurement results of the pickup core 8.
  • FIG. 4 (a) the absolute value of the change in magnetic flux in the pickup core 8 when there is no defect (Crack) is on the order of two digits.
  • Fig. 5 (a) the change in magnetic flux when there is a defect is on the order of three digits. This indicates that it is possible to detect a defect in the subject 7 by detecting a change in magnetic flux in the pickup core 8, that is, a corresponding change in magnetic potential difference.
  • the non-destructive inspection apparatus 20 includes the second coil 14 and the first integrator 15 (hereinafter, sometimes referred to as “external magnetic field correction unit” for simplicity).
  • the second coil 14 includes the second coil 14 and the first integrator 15 (hereinafter, sometimes referred to as “external magnetic field correction unit” for simplicity).
  • the horizontal axis is the distance (gap) between the exciting core 6 and the subject 7, and the vertical axis is the ratio of the core magnetic flux to the change in the gap of the exciting core 6.
  • a solid line indicates a case where it is controlled by the external magnetic field correction unit, and a broken line indicates a case where it is not controlled by the external magnetic field correction unit.
  • the horizontal axis is the frequency of the alternating current applied to the exciting core 6, and the vertical axis is the magnetic flux density when the frequency is changed! /, NA! /, And the magnetic flux when the frequency is changed.
  • the nondestructive inspection apparatus of the present invention prevents a part of the transmitted magnetic flux from passing through a magnetic path provided between the two points and provided outside the subject.
  • a reverse magnetic field applying means for applying a reverse magnetic field is provided, and the magnetic potential difference measuring means measures the magnetic potential difference between the two points from the strength of the magnetic field of the reverse magnetic field.
  • the reverse magnetic field applying means applies a reverse magnetic field so that a part of the transmitted magnetic flux does not pass through a magnetic path provided outside the subject by connecting the two points.
  • the magnetic potential difference measuring means measures a magnetic potential difference between the two points from the strength of the reverse magnetic field.
  • the nondestructive inspection apparatus of the present invention includes an external magnetic field applying unit that applies an external magnetic field that generates the transmitted magnetic flux from the outside of the subject, and the transmitted magnetic flux is constant. It is preferable to provide an external magnetic field correcting means for correcting the strength of the external magnetic field.
  • the transmitted magnetic flux inside the subject is constant even when the distance between the external magnetic field applying means and the subject is increased. Therefore, in the nondestructive inspection apparatus, a nondestructive inspection device is provided. The effect of lift-off due to the change in the distance between the device and the subject can be removed. Further, the nondestructive inspection apparatus of the present invention, in addition to the above configuration, the external magnetic field applying means increases the magnetic permeability inside the coil, the coil generating a magnetic field according to the flowing current, and the external magnetic field It is preferable to include an excitation core for applying to the subject.
  • the excitation core is made of a material that increases the magnetic permeability inside the coil, for example, a high permeability material such as amorphous ferrite or high permeability steel, so that the strength of the external magnetic field applied to the subject is increased.
  • the force S is used to concentrate on the measurement site of the subject.
  • the current is preferably an alternating current.
  • the characteristics of the transmitted magnetic field can be changed by changing the AC characteristics. For example, by changing the amplitude, frequency, or waveform of the alternating current or voltage, the transmitted magnetic field can be changed according to each change.
  • the nondestructive inspection apparatus of the present invention preferably includes frequency adjusting means for adjusting the frequency of the alternating current.
  • the skin effect is used by changing the frequency of the alternating current (adjusting the depth of the transmitted magnetic flux from the subject surface), the crack depth from the subject surface on the measurement side, etc. Can be measured.
  • the depth s from the surface on the measurement surface side of the subject where the magnetic flux density is approximately 37% of the surface portion is a function of the frequency ⁇ of the alternating current and is given by the following equation: I understand! /
  • ⁇ is the resistivity of the subject
  • 11 is the magnetic permeability of the subject. Therefore, the depth S is reduced by increasing the AC frequency ⁇ , and the depth S is increased by reducing the frequency ⁇ by the force S.
  • the nondestructive inspection device of the present invention preferably increases the amplitude of the alternating current gradually and then decreases it gradually.
  • the shape of the exciting core is a donut-shaped shape m / n (m ⁇ n, where m and n are integers of 1 or more It is preferable that it is a shape of one piece of those divided.
  • the excitation core adopts the shape of one of the donut-shaped shapes divided into m / n (m ⁇ n, where m and n are integers greater than or equal to 1) is doing. Therefore, it is possible to appropriately adjust the angle formed by the plane including each of the one end face and the other end face that are the measurement parts for the subject of the excitation core. For this reason, even when the object has a shape that can be obtained when the flat plate is bent at an angle that is the same as the angle formed by the flat surface, the nondestructive inspection apparatus can be used.
  • the measurement unit for the subject in the excitation core is rounded.
  • the measurement unit for the subject in the excitation core is rounded, the measurement portion of the excitation core can be applied to the subject having various shapes without changing the shape of the nondestructive inspection apparatus. Can be contacted.
  • the present invention detects crack damage in welded steel structures such as ships and bridges, and detection of crack damage in pipes made of steel and martensitic stainless steel in power plants and chemical plants.
  • the present invention can be widely applied to an inspection apparatus that detects crack damage or the like of an object made of a magnetic material.

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Abstract

Instrument d'essai non destructif ayant une dimension réduite et un poids léger et utilisé pour évaluer de façon stable une fissure rapprochée, une fissure éloignée et une fissure interne à un coût relativement faible dans un laps de temps court tout en évitant l'influence du retrait à l'aide d'un procédé de potentiomètre magnétique. Un instrument d'essai non destructif comprend un noyau de capteur (8) pour mesurer le potentiel magnétique entre deux points dans le flux magnétique transmis à travers l'intérieur de l'objet soumis à l'essai depuis l'extérieur de l'objet, une quatrième bobine (9), un second intégrateur (10), un second amplificateur de puissance (11), une troisième bobine (12), une deuxième bobine (14) et un premier intégrateur (15), ces deux derniers étant destinés à corriger l'intensité du champ magnétique externe, et un convertisseur A/N (13) et un microordinateur (1) pour détecter un défaut, si existant, à l'intérieur de l'objet en détectant une variation de la différence de potentiel magnétique mesuré lorsque le noyau de capteur est déplacé par rapport à l'objet.
PCT/JP2007/073441 2006-12-14 2007-12-05 Instrument d'essai non destructif et procédé d'essai non destructif Ceased WO2008072508A1 (fr)

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JP2006-337383 2006-12-14
JP2006337383A JP2010048552A (ja) 2006-12-14 2006-12-14 非破壊検査装置及び非破壊検査方法

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Cited By (5)

* Cited by examiner, † Cited by third party
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WO2010050155A1 (fr) * 2008-10-28 2010-05-06 Ntn株式会社 Appareil de contrôle par effet de bruit barkhausen et procédé de contrôle associé
CN103760223A (zh) * 2014-02-19 2014-04-30 华中科技大学 一种基于体表反向场的内外伤漏磁检测区分方法与装置
CN103776897A (zh) * 2014-02-18 2014-05-07 华中科技大学 一种基于缺陷磁泄漏域反向场的漏磁检测方法与装置
CN106225924A (zh) * 2016-09-30 2016-12-14 京东方科技集团股份有限公司 一种光强检测单元、光强检测器及其检测方法、显示装置
CN106248210A (zh) * 2016-07-29 2016-12-21 中国科学院西安光学精密机械研究所 一种准实体横向剪切干涉仪

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JP6740077B2 (ja) 2016-10-05 2020-08-12 大日機械工業株式会社 非破壊検査測定システムの較正装置および非破壊検査測定方法

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WO2010050155A1 (fr) * 2008-10-28 2010-05-06 Ntn株式会社 Appareil de contrôle par effet de bruit barkhausen et procédé de contrôle associé
JP2010107229A (ja) * 2008-10-28 2010-05-13 Ntn Corp バルクハウゼンノイズ検査装置および検査方法
CN103776897A (zh) * 2014-02-18 2014-05-07 华中科技大学 一种基于缺陷磁泄漏域反向场的漏磁检测方法与装置
CN103776897B (zh) * 2014-02-18 2015-05-06 华中科技大学 一种基于缺陷磁泄漏域反向场的漏磁检测方法与装置
CN103760223A (zh) * 2014-02-19 2014-04-30 华中科技大学 一种基于体表反向场的内外伤漏磁检测区分方法与装置
CN103760223B (zh) * 2014-02-19 2015-04-15 华中科技大学 一种基于体表反向场的内外伤漏磁检测区分方法与装置
CN106248210A (zh) * 2016-07-29 2016-12-21 中国科学院西安光学精密机械研究所 一种准实体横向剪切干涉仪
CN106225924A (zh) * 2016-09-30 2016-12-14 京东方科技集团股份有限公司 一种光强检测单元、光强检测器及其检测方法、显示装置

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