JP5297791B2 - Nondestructive inspection apparatus and nondestructive inspection method - Google Patents

Description

  The present invention performs a nondestructive inspection using a guide wave on a pipe body such as a pipe, and evaluates a long distance at once for the presence or absence of defects such as thinning that are supposed to occur in the pipe material. The present invention relates to an inspection apparatus and a nondestructive inspection method.

  In piping that constitutes a power plant, chemical plant, or the like, the piping may deteriorate due to corrosion or erosion of the inner surface of the piping due to liquid or gas flowing inside the piping during long-term operation. Therefore, regular monitoring and inspection or appropriate repair is necessary. If neglected, the pipe may be thinned, and the thinning may further progress to form a through hole. In this case, the fluid inside the pipe such as liquid or steam leaks, and normal operation of the plant cannot be ensured, so the operation must be stopped for a long time. For this reason, it is necessary to evaluate the soundness of the pipe by a nondestructive inspection method for managing the thickness and material state of the pipe, and to take measures such as replacement and repair of the pipe as necessary.

  As a typical nondestructive inspection method, there is a thickness measurement method by an ultrasonic pulse reflection method defined in JIS Z 2355: 2005 (see Non-Patent Document 1). In general, a method using an ultrasonic thickness meter including an ultrasonic probe and a transmitter / receiver is used. The ultrasonic thickness meter transmits ultrasonic waves in the plate thickness direction of the pipe to be inspected, and the ultrasonic propagation time when the ultrasonic wave reflected by the pipe bottom surface is received by the ultrasonic probe and in the known material. The pipe thickness of the pipe can be measured with high accuracy by the principle of obtaining the board thickness using the ultrasonic velocity, but the effective inspection range is limited to the contact area between the ultrasonic probe and the pipe.

  However, if the inspection range is wide, such as pipes with large pipe diameters or lengths ranging from several meters to several tens of meters, the number of measurement points by the ultrasonic thickness gauge increases, which increases the inspection time. There is. In addition, for pipes that are difficult to access by inspectors and inspection equipment, such as pipes with insulation material, underground pipes buried in concrete or concrete, rising pipes installed at high places, etc. The time required for preparation and tidying up also increases.

  In view of this, an inspection technique using a guide wave, which is a kind of ultrasonic wave, is being introduced. Guided wave inspection can inspect long distances at a time, and only when a significant difference is found in this inspection, if the true meaning is confirmed by measurement using the ultrasonic thickness gauge, etc. Work time can be shortened.

  In general, in the inspection using a guide wave, a fundamental mode (order is expressed by 0 or 1) having low dispersibility and capable of long-distance propagation is used. However, when the transmitter of the ultrasonic probe 2 is distributed in the circumferential direction, or when a discontinuous portion such as a thinned portion or a support exists in a part of the pipe circumferential direction, a higher-order mode is generated. . Since the high-order mode has a complicated vibration form, it is difficult to evaluate the waveform received by the probe. As the pipe diameter increases, the group velocity difference decreases, making it difficult to separate the fundamental mode and the higher order mode. Further, the guide wave propagating through the pipe generates a reflected wave on the upstream side of the transmission wave when there is a change in the thickness of the thinned portion or the like. The defect can be detected by receiving the reflected wave.

  As a conventional inspection method using a guide wave, it consists of a transmission sensor and a reception sensor that inject ultrasonic waves into a pipe, and the guide wave is separated into modes with different circumferential distributions, which are theoretically required for each mode. There is known an apparatus that obtains an evaluation image of a pipe using a spatial wave after calculating a spatial wave at an arbitrary time by adding dispersion curve data (see, for example, Patent Document 1). In this method, it is an important condition for correctly identifying a defect image and increasing the inspection accuracy that a highly accurate dispersion curve and different modes can be separated in the circumferential direction.

JP 2006-53134 A Japanese Industrial Standards JIS Z 2355: 2005

  In the method described in Patent Document 1, when the pipe diameter is small, a difference in group velocity is likely to occur between the basic mode and the higher-order mode, so that it is possible to improve defect identification. However, when the pipe diameter is large, the difference between the group velocities of the basic mode and the higher-order mode is small, so that it is difficult to separate different modes in the circumferential direction, and it is difficult to improve visualization.

  Here, there is an upper limit to the number of reception channels of the guide wave inspection apparatus. In this case, only the upper limit number of reception channels of the guide wave inspection device can be arranged as signal measurement points in the circumferential direction of the pipe. Even when a large number of probes are placed in the pipe circumferential direction, multiple probes are connected so that the number of measurement points becomes the upper limit of the number of reception channels of the guide wave inspection device, and the received signal is sent to the guide wave inspection device. Need to be entered as In this case, if the guide wave inspection result is visualized, a virtual image may be generated separately from the signal image from the defect, and it is difficult to distinguish the defect signal from the virtual image.

  As described above, when the number of measurement points is limited, a defect signal and a virtual image are mixed, but a method for correctly identifying them is necessary. By making this identification correct, the detection accuracy of the thinned portion can be improved, and appropriate soundness evaluation, management, repair, and replacement can be performed.

  An object of the present invention is to provide a nondestructive inspection apparatus and method using a guide wave that can identify a thinned portion signal generated in a pipe as a virtual image and improve detection accuracy of the thinned portion in a nondestructive inspection using a guide wave. Is to provide.

(1) In order to achieve the above object, the present invention provides a guide wave flaw detector that transmits a guide wave to a tube body, receives a guide wave from the tube body, and obtains reception information based on the received signal; A flaw detection waveform storage device for storing the received information, a flaw detection result imaging device for visualizing a flaw detection result based on the reception information, and a plurality of guide waves for different frequencies visualized by the flaw detection result imaging device A flaw detection result diagnosis device that performs a calculation process for identifying a defect signal and a virtual image signal by correlating inspection images, and the guide wave flaw detection device includes a plurality of transmission / reception circuits and a plurality of ultrasonic probes. the predetermined number to one of said transmitting and receiving circuit ultrasonic probe is obtained by the so that is wired.
With such a configuration, in the nondestructive inspection using the guide wave, the thinned portion signal generated in the pipe can be identified as a virtual image, and the detection accuracy of the thinned portion can be improved.

  (2) In the above (1), preferably, the flaw detection result diagnosis apparatus correlates a plurality of guided wave inspection images for different frequencies, and identifies the defect signal when the correlation value exceeds a threshold value. It is what I did.

  (3) In the above (1), preferably, the guided wave flaw detector performs a guided wave inspection by individually transmitting and receiving guide waves of a plurality of frequencies to the tubular body, and the flaw detection result imaging device includes: Imaging based on received waves for a plurality of frequencies obtained in the guide wave inspection is performed for each frequency.

  (4) In the above (1), preferably, the guide wave flaw detector performs a guide wave inspection by transmitting and receiving a guide wave including a plurality of frequencies to the tube body, and the flaw detection result imaging device includes The received waves corresponding to a plurality of frequencies obtained in the guide wave inspection are discriminated by a filter that transmits each frequency and then imaged.

(5) In the above (1), preferably, the guided wave flaw detector has 2 to 4 transmission / reception circuits, and the tube body is an inspection object.
( 6 ) Further, in order to achieve the above object, the present invention is a nondestructive inspection method for performing inspection by transmitting and receiving a guide wave to a tubular body, comprising a plurality of transmission / reception circuits and a plurality of ultrasonic probes. A guide wave inspection using a plurality of frequencies is performed by a guide wave flaw detector in which a predetermined number of the ultrasonic probes are connected to one of the transmission / reception circuits , and obtained in the guide wave inspection. The imaging based on the received wave is performed at each frequency, and the correlation value of the signal intensity with respect to the imaging is calculated, so that the defect signal and the virtual image signal are identified.
By this method, in the nondestructive inspection using the guide wave, the thinned portion signal generated in the pipe can be identified as a virtual image, and the detection accuracy of the thinned portion can be improved.

  According to the present invention, in a nondestructive inspection using a guide wave, a thinned portion signal generated in a pipe can be identified as a virtual image, and the detection accuracy of the thinned portion can be improved.

Hereinafter, the configuration and operation of the nondestructive inspection apparatus using the guide wave according to the first embodiment of the present invention will be described with reference to FIGS.
First, the overall configuration of the nondestructive inspection apparatus using the guide wave according to the present embodiment will be described with reference to FIG.
FIG. 1 is an explanatory diagram of the overall configuration of a nondestructive inspection apparatus using a guide wave according to the first embodiment of the present invention.

  The guide wave flaw detector 4 is a device that propagates a guide wave into and receives a guide wave from the tube. The main components are a trigger signal generator 5 and a plurality of transmission / reception circuits 61, 62, 63, 64 and the digital signal converter 10.

  The transmission / reception circuits 61,..., 64 have the same configuration and function and perform the same operation. The ultrasonic probes 21, 22, 23, and 24 installed in the pipe 1 have the same configuration and performance and perform the same operation. The ultrasonic probes 21, 22, 23, 24 are arranged at equal intervals with a 90 ° interval in the circumferential direction of the pipe 1. The ultrasonic probe 24 is disposed on the opposite side of the circumferential direction 180 ° with respect to the ultrasonic probe 22. The transmission / reception circuits 61, ..., 64 and the ultrasonic probes 21, ..., 24 are connected by the electric wires 11 so as to correspond one-to-one.

  In the following description, a circuit related to the transmission / reception circuit 61 and the ultrasonic probe 21 will be described, but the same applies to other transmission / reception circuits and the ultrasonic probe.

  The trigger signal transmitted from the trigger signal generator 5 is sent to the transmission / reception circuit 61. The transmission signal is transmitted from the arbitrary waveform generator 7 in response to the trigger signal, and is sent to the ultrasonic probe 21 after the signal amplitude is enhanced by the amplification amplifier 8.

  The ultrasonic probe 21 that has received the transmission signal transmits an ultrasonic wave into the pipe and induces a guide wave to propagate in the pipe. When there is a discontinuous portion such as thinning in the pipe, a reflected wave is generated toward the upstream direction (propagation origin) of the guide wave that is a transmission wave, which is received by the ultrasonic probe 21.

  The reception signal from the ultrasonic probe 21 is amplified in amplitude by the reception amplifier 9 of the transmission / reception circuit 61, sent to the digital signal converter 10, converted into a digital signal, and stored in the flaw detection waveform storage device 12. The Here, since the ultrasonic probes 21,..., 24 are connected to the individual transmission / reception circuits 61,..., 64 by the electric wires 11, the reception signals of the respective ultrasonic probes can be individually recorded and stored.

Here, the inspection principle by the nondestructive inspection apparatus using the guide wave according to the present embodiment will be described with reference to FIGS.
FIG. 2 is an explanatory diagram of an inspection principle by a nondestructive inspection apparatus using a guide wave according to the first embodiment of the present invention. FIG. 3 is an explanatory diagram of a dispersion curve of a guide wave propagating through a pipe by the nondestructive inspection apparatus using the guide wave according to the first embodiment of the present invention.

  As shown in FIG. 2, a plurality (four in the illustrated example) of ultrasonic probes 21, 22, 23 and 24 are arranged in the pipe circumferential direction of the pipe 1. When ultrasonic waves are transmitted from the ultrasonic probes 21, ..., 24 to the pipe 1, a guide wave GW is generated in the pipe 1, and this guide wave propagates in the pipe axis direction. If there is a thinned portion (defect portion) DP in the pipe 1, the guide wave is reflected there, propagates through the pipe 1 as a reflected wave RW, and is received by the ultrasonic probes 21, 22, 23, and 24. At this time, it is common to use an ultrasonic frequency in the range of several tens kHz to several hundreds kHz. A magnetostrictive sensor may be used instead of the ultrasonic probe.

  The guide wave has a specific vibration mode and is expressed using a dispersion curve.

  FIG. 3 shows a part of a dispersion curve in a carbon steel pipe having a diameter of 318 mm and a plate thickness of 10.3 mm. The horizontal axis is the guide wave frequency, the vertical axis is the group velocity which is the propagation sound velocity of each vibration mode, and one vibration mode is represented by one line. That is, even in the same mode, the group velocity differs depending on the frequency at the time of propagation. The vibration modes of the guide wave can be broadly divided into longitudinal vibration mode (L), bending vibration mode (F), and torsional vibration mode (T). The numbers in parentheses in the figure are the thickness or the order of the pipe circumferential mode. The higher the order, the more complicated the vibration form and the higher order mode propagates.

Next, the configuration of the guide wave sensor 3 used in the nondestructive inspection apparatus using the guide wave according to the present embodiment will be described with reference to FIGS. 4 and 5.
FIG. 4 is a first configuration diagram of the guide wave sensor used in the nondestructive inspection apparatus using the guide wave according to the first embodiment of the present invention. FIG. 5 is a second block diagram of the guide wave sensor used in the nondestructive inspection apparatus using the guide wave according to the first embodiment of the present invention.

  As shown in FIG. 4, the guide wave sensor 3 installed in the straight pipe portion of the pipe 1 includes guide wave sensor rings 3 a and 3 b having half cracks, a plurality of ultrasonic probes 21,. And a wave sensor fixture 3c. The ultrasonic probes 21,..., 24 are installed on the guide wave sensor rings 3 a, 3 b, the guide wave sensor rings 3 a, 3 b are combined on the outer surface of the pipe, and the pipe 1 and the guide wave sensor ring are connected by the guide wave sensor fixture 3 c. Fix so that 3a and 3b do not shift. As a result, the ultrasonic probes 21,..., 24 can stably contact the pipe, and can transmit and receive ultrasonic waves into the pipe.

  The guide wave sensor 3 replaces the guide wave sensor rings 3a and 3b according to the pipe diameter, but the basic configuration is the same.

  FIG. 5 shows a case where the pipe diameter is large. When the pipe diameter is large, a large number of ultrasonic probes 2 can be arranged in the circumferential direction. However, since there is an upper limit in the transmission / reception circuits 61,..., 64 constituting the guide wave flaw detector 4, it is necessary to connect a plurality of ultrasonic probes and handle them as the same system. For example, as shown in FIG. 1, when there are four transmission / reception circuits, three ultrasonic probes are connected and handled as the same system in order to treat the circumferential direction 90 ° as one segment.

  The flaw detection result imaging apparatus 13 shown in FIG. 1 obtains and displays a plane development view of the flaw detection result by calculation based on the received wave stored in the flaw detection waveform storage device 12. In this imaging method, processing based on the aperture synthesis method is generally performed. In this method, at any evaluation point within the flaw detection range, the propagation time of the ultrasonic wave is calculated based on the distance between the evaluation point and each ultrasonic probe or measurement point position and the group velocity that is the sound velocity of the guide wave. .

  Next, the signal value at the evaluation point is obtained, and the signal value at the propagation time calculated above in the reception wave of each ultrasonic probe is added. The evaluation point is moved to calculate the signal value in the entire evaluation range, and the result is displayed as a plan development view. Further, information necessary for imaging (pipe dimensions, probe arrangement, material sound speed, etc.) is input to the flaw detection result imaging apparatus 13 in advance.

  Further, the flaw detection result imaging device 13 and a display device 15 are connected to the flaw detection result diagnostic device 14.

Next, the inspection method by the nondestructive inspection apparatus using the guide wave according to the present embodiment will be described with reference to FIGS.
FIG. 6 is a flowchart showing the contents of the inspection method by the nondestructive inspection apparatus using the guide wave according to the first embodiment of the present invention. FIGS. 7 to 9 are explanatory views of a flat developed image obtained by the inspection method by the nondestructive inspection apparatus using the guide wave according to the first embodiment of the present invention.

  In the present embodiment, the guided wave flaw detector 4 performs a guided wave inspection at a plurality of frequencies.

  First, in step 101, the guide wave flaw detector 4 executes an inspection in which a guide wave is transmitted and received at a frequency αHz. Next, in step 103, the guided wave flaw detector 4 stores the obtained inspection result in the flaw detection waveform storage device 12. Next, in step 105, the received wave in step 103 is output to the flaw detection result imaging apparatus 13, and imaging is performed with the received wave having a frequency of α Hz.

  Further, in step 102, the guide wave flaw detector 4 performs an inspection in which a guide wave is transmitted and received at a frequency βHz. Next, in step 104, the guide wave flaw detector 4 stores the obtained inspection result in the flaw detection waveform storage device 12. Next, in step 106, the received wave of step 104 is output to the flaw detection result imaging apparatus 13, and imaging is performed with the received wave having a frequency of βHz.

  Next, in step 107, the flaw detection result diagnosis apparatus 14 calculates a correlation value for the imaging result obtained in steps 105 and 106 and performs correlation evaluation. Further, in step 108, the flaw detection result diagnosis device 14 identifies a defect when the correlation value in both results exceeds the threshold value. The threshold value depends on the size of the defect to be detected and can be determined and input by the user.

  Next, the results of evaluation by the method shown in FIG. 6 will be described with reference to FIGS. Here, a case where four ultrasonic probes are arranged in the circumferential direction in a pipe having a diameter of 318 mm and a guided wave inspection is performed will be described as an example.

  FIG. 7 is a planar development image of the guide wave inspection result at a frequency of 40 kHz, which is obtained by step 105 in FIG.

  In FIG. 7, the horizontal axis represents the position in the pipe axis direction, and the vertical axis represents the position in the circumferential direction. Further, the shade of the color in the figure indicates the strength of the sound source of the reflected signal, and the dark portion has a high signal intensity. Moreover, since it is piping, the upper and lower of the circumferential direction position become the same coordinate.

  In the example shown in FIG. 7, four ultrasonic probes 2 are arranged in the circumferential direction with a pipe having a diameter of 318 mm (indicated by □ in the figure), and the reflected wave from the thinning after 3 m is virtually calculated, Based on this reflected wave, a plane development view is obtained by aperture synthesis processing.

  In this figure, the position indicated by ◯ is the position assuming the thinned portion, and it can be seen that a strong signal can be detected at that position and the thinned portion can be identified. However, although an image with a strong signal level is generated even at the position indicated by Δ, since there is no reflected signal sound source here, the signal at the position indicated by Δ is a calculated virtual image.

  One of the reasons why a virtual image is generated is that there are insufficient measurement points in the circumferential direction. For this reason, if about 16 ultrasonic probes are placed in the circumferential direction and received waves can be obtained individually, and the imaging process is performed, the generation of virtual images can be suppressed. However, as described above, since there is an upper limit number of reception channels of the guide wave inspection apparatus, it is not always possible to increase the number of ultrasonic probes and increase the number of measurement points.

  Next, FIG. 8 is a planar development image of a guide wave inspection result at a frequency of 60 kHz, which is obtained by step 106 in FIG. In the example shown in FIG. 8, since the frequency is higher than in the example shown in FIG. 7, both the defect signal indicated by ◯ and the virtual image indicated by Δ are somewhat smaller. Further, the position of the virtual image changes.

  FIG. 9 shows the result of evaluating the correlation between the flat developed image at a frequency of 40 kHz in FIG. 7 and the flat developed image at a frequency of 60 kHz in FIG. It is obtained.

  In FIG. 9, color shading indicates a correlation value, and the correlation value is high in a dark portion. By correlating both figures, the defect images in the two figures are generated at the same position, so the correlation value is high. However, since the position of the image of the virtual image is changed by changing the frequency, the correlation value is low, and only the defective portion of the image has a high signal intensity. Here, by setting an appropriate threshold value as shown in step 108 of FIG. 6, the portion surrounded by ◯ can be identified as a defect.

  In FIG. 1, the flaw detection waveform storage device 12, the flaw detection result imaging device 13, the flaw detection result diagnostic device 14, and the display device 15 are drawn as individual devices, but these devices and functions are mounted in one device. It is also possible to do.

  Here, in this embodiment, the case where two frequencies are used is described. However, it is desirable to use three or more frequencies in order to improve the visualization and correlation and perform reliable evaluation, and the procedure is as follows. This is the same as the processing content of FIG.

  According to the present embodiment, in the nondestructive inspection using the guide wave, the thinned portion signal generated in the pipe can be identified as a virtual image, and the detection accuracy of the thinned portion can be improved. In particular, piping having a large diameter is effective because a possibility that a virtual image is generated is high.

  Next, the configuration and operation of a nondestructive inspection apparatus using a guide wave according to the second embodiment of the present invention will be described with reference to FIG. The overall configuration of the nondestructive inspection apparatus using the guide wave according to this embodiment is the same as that shown in FIG. That is, the configurations of the guide wave sensor 3, the guide wave flaw detector 4, the flaw detection waveform storage device 12, and the display device 15 are the same as those in the first embodiment. However, the functions of the flaw detection result imaging apparatus 13 and the flaw detection result diagnostic apparatus 14 are different.

  FIG. 10 is a flowchart showing the contents of the inspection method by the nondestructive inspection apparatus using the guide wave according to the second embodiment of the present invention.

  In the first embodiment, a plurality of guided wave inspections are necessary, but in this embodiment, a guided wave inspection using incident waves including two or more frequency bands is performed. For this reason, the guide wave inspection is performed only once, and the inspection time can be shortened.

  In step 110 of FIG. 10, the guided wave flaw detector 4 performs a guided wave inspection using incident waves including two or more frequency bands.

  Next, in step 111, the guide wave flaw detector 4 stores the received wave in the flaw detection waveform storage device 12. In order to evaluate the received wave, the received wave is output to the flaw detection result imaging apparatus 13 in step 112.

  Here, in step 113, the flaw detection result imaging apparatus 13 applies a frequency filter that can extract only a specific frequency band component to the received wave. For example, it can be evaluated as a received wave having a frequency of α Hz by using an α Hz band filter. Then, using this received wave, in step 115, the flaw detection result imaging apparatus 13 performs imaging using the received wave having the frequency αHz.

  In step 114, the flaw detection result imaging apparatus 13 applies a frequency filter that can extract only a specific frequency band component to the received wave. For example, it can be evaluated as a received wave having a frequency of β Hz using a β Hz band filter. Then, using this received wave, in step 116, the flaw detection result imaging apparatus 13 performs imaging using the received wave having a frequency of β Hz.

  Next, in step 107, the flaw detection result diagnosis apparatus 14 calculates a correlation value for the imaging results obtained in steps 115 and 116 and performs correlation evaluation. Further, in step 108, the flaw detection result diagnosis device 14 identifies a defect when the correlation value in both results exceeds the threshold value. The threshold value depends on the size of the defect to be detected and can be determined and input by the user.

  According to the present embodiment, in the nondestructive inspection using the guide wave, the thinned portion signal generated in the pipe can be identified as a virtual image, and the detection accuracy of the thinned portion can be improved. In particular, piping having a large diameter is effective because a possibility that a virtual image is generated is high.

Further, the guide wave inspection is performed only once, and the inspection time can be shortened.

It is explanatory drawing of the whole structure of the nondestructive inspection apparatus using the guide wave by the 1st Embodiment of this invention. It is explanatory drawing of the test | inspection principle by the nondestructive test | inspection apparatus using the guide wave by the 1st Embodiment of this invention. It is explanatory drawing of the dispersion | distribution curve of the guide wave which propagates piping by the nondestructive inspection apparatus using the guide wave by the 1st Embodiment of this invention. It is a 1st block diagram of the guide wave sensor used for the nondestructive inspection apparatus using the guide wave by the 1st Embodiment of this invention. It is a 2nd block diagram of the guide wave sensor used for the nondestructive inspection apparatus using the guide wave by the 1st Embodiment of this invention. It is a flowchart which shows the content of the inspection method by the nondestructive inspection apparatus using the guide wave by the 1st Embodiment of this invention. It is explanatory drawing of the planar expansion | deployment image | video obtained by the inspection method by the nondestructive inspection apparatus using the guide wave by the 1st Embodiment of this invention. It is explanatory drawing of the planar expansion | deployment image | video obtained by the inspection method by the nondestructive inspection apparatus using the guide wave by the 1st Embodiment of this invention. It is explanatory drawing of the planar expansion | deployment image | video obtained by the inspection method by the nondestructive inspection apparatus using the guide wave by the 1st Embodiment of this invention. It is a flowchart which shows the content of the inspection method by the nondestructive inspection apparatus using the guide wave by the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pipe 2, 21, 22, 23, 24 ... Ultrasonic probe 3 ... Guide wave sensor 3a, 3b ... Guide wave sensor ring 3c ... Guide wave sensor ring fixing tool 4 ... Guide wave flaw detector 5 ... Transmission trigger generation Devices 6, 61, 62, 63, 64 ... Transmission / reception circuit 7 ... Arbitrary waveform generator 8 ... Amplification amplifier 9 ... Reception amplifier 10 ... Digital signal converter 11 ... Wire 12 ... Flaw detection result storage device 13 ... Flaw detection result imaging device 14 ... flaw detection result diagnosis device 15 ... display device GW ... guide wave DP ... thinning part RW ... reflected wave

Claims (6)

A guide wave flaw detector for transmitting a guide wave to the tube and receiving a guide wave from the tube, and obtaining received information based on the received signal;
A flaw detection waveform storage device for storing the received information;
A flaw detection result imaging apparatus for visualizing flaw detection results based on the received information;
A flaw detection result diagnosis device that performs an arithmetic process for identifying a defect signal and a virtual image signal by correlating a plurality of guided wave inspection images for different frequencies imaged by the flaw detection result imaging device ,
Nondestructive said guided wave inspection apparatus includes a plurality of transmitting and receiving circuits and a plurality of ultrasonic probes, the predetermined number to one of said transmitting and receiving circuit ultrasonic probe characterized by Rukoto is connected Inspection device. The nondestructive inspection apparatus according to claim 1,
The non-destructive inspection apparatus characterized in that the flaw detection result diagnosis apparatus correlates a plurality of guide wave inspection images for different frequencies, and identifies the defect signal when the correlation value exceeds a threshold value. The nondestructive inspection apparatus according to claim 1,
The guided wave flaw detector performs a guided wave inspection by separately transmitting and receiving guide waves of a plurality of frequencies to the tube body,
The flaw detection result imaging apparatus performs imaging based on received waves for a plurality of frequencies obtained in the guide wave inspection for each frequency. The nondestructive inspection apparatus according to claim 1,
The guided wave flaw detector performs a guided wave inspection by transmitting and receiving a guide wave including a plurality of frequencies to the tubular body,
The non-destructive inspection apparatus characterized in that the flaw detection result imaging apparatus visualizes a received wave with respect to a plurality of frequencies obtained in the guide wave inspection after discrimination by a filter that transmits each frequency.   The nondestructive inspection apparatus according to claim 1,
  The non-destructive inspection apparatus according to claim 1, wherein the guided wave flaw detection apparatus includes 2 to 4 transmission / reception circuits, and the tube body is an inspection target. A nondestructive inspection method in which a guide wave is transmitted to and received from a tubular body for inspection,
Guide wave inspection using a plurality of frequencies in a guide wave flaw detector having a plurality of transmission / reception circuits and a plurality of ultrasonic probes, wherein a predetermined number of the ultrasonic probes are connected to one transmission / reception circuit. Carried out
The imaging based on the received wave obtained in the guided wave inspection is performed at each frequency,
A non-destructive inspection method, wherein a defect value and a virtual image signal are identified by calculating a correlation value of signal intensity with respect to the imaging.

Images