JP6298371B2 - Ultrasonic flaw detection apparatus and ultrasonic flaw detection method - Google Patents

Description

  The present invention relates to an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method for inspecting piping.

  Pipes of power plants, chemical / petroleum plants, etc. may have crack defects (specifically, crevice corrosion, stress corrosion cracking, etc.) on the inner surface depending on the operating environment. Therefore, it is necessary to inspect the piping by ultrasonic flaw detection and the like to evaluate the soundness of the piping.

  As described in Patent Literature 1 and the like, the phased array type ultrasonic flaw detection method uses an array sensor having a plurality of piezoelectric elements. Then, a driving signal is transmitted to each piezoelectric element, and an ultrasonic wave is transmitted from each piezoelectric element to the inside of the pipe. At this time, by delaying the drive signal transmitted to each piezoelectric element based on the delay pattern, the ultrasonic beam transmission timing of each piezoelectric element is shifted to focus the ultrasonic beam. Therefore, it is possible to change the focal position, transmission angle, etc. of the ultrasonic beam by the delay pattern.

JP 2010-276465 A

  When flaw detection is performed for cracks that have developed in the circumferential direction of the pipe, ultrasonic waves are transmitted and received in the axial direction of the pipe. For this reason, it is preferable to perform sector electronic scanning in which a plurality of piezoelectric elements are arranged in the axial direction of the pipe and the beam transmission angle in the axial cross section of the pipe is changed.

  On the other hand, when flaw detection is performed on a crack that has developed in the axial direction of the pipe, ultrasonic waves are transmitted and received in the circumferential direction of the pipe. Therefore, it is preferable to perform sector electronic scanning in which a plurality of piezoelectric elements are arranged in the circumferential direction of the pipe and the beam transmission angle in the circumferential cross section of the pipe is changed. Further, in order to efficiently make the ultrasonic beam enter the pipe, it is preferable to provide a shoe (wedge material) between the array sensor and the pipe, and to bring the curved surface of the shoe into contact with the outer peripheral surface of the pipe. However, if the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is not good (specifically, for example, the circumferential edge of the curved surface of the shoe and the outer peripheral surface of the pipe are in contact with each other) If the other side edge of the curved surface of the curved surface does not contact the outer peripheral surface of the pipe and a gap is formed), a deviation occurs in the refraction angle of the ultrasonic wave and the path length, and the detection accuracy and reliability decrease. .

  The present invention has been made in view of the above-described matters, and an object of the present invention is to provide an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method that can improve detection accuracy and reliability.

  In order to achieve the above object, an ultrasonic flaw detector of the present invention includes a shoe having a curved surface in contact with an outer peripheral surface of a pipe, and an array sensor having a plurality of piezoelectric elements arranged in the circumferential direction of the pipe, An ultrasonic flaw detection probe that transmits an ultrasonic beam toward the circumferential direction of the pipe through the shoe from the array sensor and receives a reflected wave; the probe is movable in the circumferential direction of the pipe; and the shoe A probe scanning mechanism capable of adjusting the contact state between the curved surface of the pipe and the outer peripheral surface of the pipe, and sector electronic scanning for changing the beam transmission angle at an arbitrary probe position, and the waveform of the reflected wave for each beam transmission angle Extracts waveform data of multiple reflected waves at at least two beam transmission angles from waveform data acquired at any probe position and transmission / reception unit that acquires data A contact state determination unit that determines whether or not the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is good by comparing the extracted waveform data with each other; When it is determined that the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is good, the waveform data acquired at an arbitrary probe position is stored in a data storage unit, while the curved surface of the shoe and the pipe The probe scanning mechanism adjusts the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe, and then the sector electronic scanning is performed again by the transmitting / receiving unit. Let it run.

  In order to achieve the above object, the present invention provides an ultrasonic flaw detector comprising a shoe having a curved surface in contact with the outer peripheral surface of a pipe, and an array sensor having a plurality of piezoelectric elements arranged in the circumferential direction of the pipe. An ultrasonic flaw detection method that uses a probe to transmit an ultrasonic beam from the array sensor toward the circumferential direction of the pipe through the shoe and receive a reflected wave, wherein a beam transmission angle is set at an arbitrary probe position. By executing sector electronic scanning to change, waveform data of reflected waves is acquired for each beam transmission angle, and among waveform data acquired at arbitrary probe positions, waveform data of multiple reflected waves at at least two beam transmission angles is obtained. By extracting and comparing the extracted waveform data with each other, it is determined whether the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is good, When it is determined that the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is good, the waveform data acquired at an arbitrary probe position is stored in the data storage unit, while the curved surface of the shoe and the pipe When it is determined that the contact state with the outer peripheral surface is not good, the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is adjusted, and then the sector electronic scanning is performed again.

  According to the present invention, detection accuracy and reliability can be improved.

It is a block diagram showing the structure of the ultrasonic flaw detector in one Embodiment of this invention. It is the top view showing schematic structure of the ultrasonic flaw detection probe and probe scanning mechanism in one embodiment of the present invention, and an arrow line view by section AA. It is the schematic showing the contact state of the curved surface of the shoe | hook of the probe in one Embodiment of this invention, and the outer peripheral surface of piping, and shows the case where a contact state is favorable and the case where it is not favorable. It is a flowchart for demonstrating the procedure of the ultrasonic flaw detection method in one Embodiment of this invention. It is a figure showing the flaw detection image and waveform data as a specific example in case the contact state of the curved surface of the shoe | hook of the probe in one Embodiment of this invention and the outer peripheral surface of piping is favorable. It is a figure showing the flaw detection image and waveform data as a specific example in case the contact state of the curved surface of the shoe | hook of the probe and outer peripheral surface of piping in one Embodiment of this invention is not favorable.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the ultrasonic flaw detector according to this embodiment. Fig.2 (a) is a top view showing schematic structure of the ultrasonic flaw detection probe and probe scanning mechanism in this embodiment, FIG.2 (b) is the arrow by sectional arrow AA in Fig.2 (a). FIG.

  The ultrasonic flaw detector of this embodiment is generated on the inner peripheral surface 2 of the pipe 1 and in the axial direction of the pipe 1 (the vertical direction in FIG. 2A and the direction perpendicular to the paper surface in FIG. 2B). The purpose is to detect the crack 3 that has progressed, and includes an ultrasonic flaw detection probe 4, a probe scanning mechanism 5, a transmission / reception unit 6, a calculator 7, an input unit 8, and a display unit 9. The input unit 8 is composed of, for example, a keyboard and a mouse.

  The ultrasonic flaw detection probe 4 includes an array sensor 10 and a shoe (wedge material) 11 provided on the ultrasonic transmission / reception side (the lower side in FIGS. 1 and 2B) of the array sensor 10. The shoe 11 has a curved surface 12, and the curved surface 12 comes into contact with the outer peripheral surface 13 of the pipe 1. Note that the radius of curvature of the curved surface 12 of the shoe 11 is substantially the same as the radius of curvature of the outer peripheral surface 13 of the pipe 1 (in practice, the outer peripheral surface 13 of the pipe 1 is considered in consideration of tolerances at the time of manufacturing the pipe 1. Slightly larger than the radius of curvature). The curved surface 12 of the shoe 11 is coated with an ultrasonic contact medium.

  The probe scanning mechanism 5 is provided so as to be movable along an annular rail 15 attached to the outer peripheral side of the pipe 1 via a plurality of (three in this embodiment) fixing jigs 14. A moving body 16, a moving mechanism (not shown, configured by a motor or the like) that moves the moving body 16 along the rail 15, and an encoder (not shown) that detects the amount of movement of the moving body 16 It has.

  In addition, the probe scanning mechanism 5 is rotatably provided on the moving body 16 and supports a support shaft 17 that supports the probe 4 and a rotation mechanism that rotates the support shaft 17 (not shown, but configured by a motor or the like). And. The axis (rotation axis) of the support shaft 17 extends in the axial direction of the pipe 1 and is aligned with the center point C of the ultrasonic transmission / reception surface of the array sensor 10.

  The moving body 16 moves along the rail 15 so that the probe 4 can be moved in the circumferential direction of the pipe 1. Further, by rotating the support shaft 17, the inclination of the probe 4 with respect to the outer peripheral surface 13 of the pipe 1 is adjusted, and the contact state between the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 can be adjusted.

  The array sensor 10 has a plurality of piezoelectric elements 18 arranged in the circumferential direction of the pipe 1. The piezoelectric element 18 oscillates by a drive signal (pulse voltage) from the pulsar 19 of the transmission / reception unit 6 and transmits ultrasonic waves through the shoe 11 in the circumferential direction of the pipe 1. At this time, based on a delay pattern to be described later, the pulse signal 19 of the transmission / reception unit 6 delays the drive signal transmitted to each piezoelectric element 18, thereby shifting the transmission timing of the ultrasonic wave of each piezoelectric element 18 and focusing the ultrasonic wave. (See the middle dotted line in FIG. 2B). Therefore, the transmission angle of the ultrasonic beam (specifically, the transmission angle based on the center point C of the array sensor 10) is changed by the delay pattern. Then, for example, multiple reflected waves (details will be described later) from the inner peripheral surface 2 of the pipe 1 and reflected waves from the crack 3 are received, converted into electrical signals, and output to the receiver 20 of the transceiver 6. Yes.

  In this embodiment, the array sensor 10 is provided on the inclined surface of the shoe 11, and the main sound axis of the array sensor 10 is normal to the curved surface 12 of the shoe 11 passing through the center point C of the array sensor 10 (FIG. 2). (B) It inclines with respect to a middle up-down direction line and the Y-axis shown in FIG. 3 (a) and FIG. Accordingly, the ultrasonic beam transmitted along the main sound axis of the array sensor 10 is incident on the crack 3 at about 45 degrees.

  The transmission / reception unit 6 includes a pulser 19, a receiver 20, a delay time control unit 21, and a data recording unit 22. The delay time control unit 21 performs sector electronic scanning that changes the beam transmission angle in the circumferential section of the pipe 1 in response to an electronic scanning command from the computer 7. More specifically, the delay time control unit 21 outputs a delay pattern set in advance corresponding to each beam transmission angle to the pulser 19 and the receiver 20. The pulser 19 delays the drive signal transmitted to each piezoelectric element 18 based on the delay pattern, and shifts the transmission timing of the ultrasonic wave of each piezoelectric element 18 to focus the ultrasonic wave. The receiver 20 delays the electrical signal received from each piezoelectric element 18 based on the delay pattern, and synthesizes them to generate waveform data. The data recording unit 22 temporarily records the waveform data generated by the receiver 20 in association with the probe position and the beam transmission angle.

  The computer 7 performs control processing, data processing, and the like in accordance with a program, and has a position control unit 23 and a calculation / analysis unit 24 as its functional configuration.

The position control unit 23 outputs a movement command of the moving body 16 to the probe scanning mechanism 5 to move the moving body 16 and inputs the amount of movement of the moving body 16 from the probe scanning mechanism 5. Control the position. That is, the position of the probe 4 is controlled. Further, for each position of the probe 4 , the above-described electronic scanning command is output to the delay time control unit 21, and information on the probe position is output to the data recording unit 22.

  The calculation / analysis unit 24 reads the waveform data acquired at the same probe position from the data recording unit 22, and based on this, the flaw detection image showing the flaw detection result in the circumferential cross section of the pipe 1 (FIG. 5A described later). And FIG. 5B). More specifically, first, interpolation processing is performed on the waveform data for each beam transmission angle. Then, the path of the waveform data is shown on the circumferential cross section of the pipe 1 (specifically, the XY coordinate system of the probe 4 shown in FIGS. To the position of the coordinate system moved by the thickness d of the central portion of. Further, the intensity of the waveform data is converted into a pixel value. And a flaw detection image is produced | generated by the position on the circumferential cross section of the piping 1, and the pixel value corresponding to this.

  The display unit 9 displays the flaw detection image generated by the calculation / analysis unit 24 and also displays waveform data at an arbitrary beam transmission angle.

  By the way, delay pattern setting, flaw detection image generation, and the like are performed assuming that the contact state between the curved surface 12 of the shoe 11 of the probe 4 and the outer peripheral surface 13 of the pipe 1 is good. That is, as shown in FIG. 3A, when the normal line of the curved surface 12 of the shoe 11 passing through the center point C of the array sensor 10 is used as the Y axis as the XY coordinate system of the probe 4 in the circumferential section of the pipe 1. Furthermore, it is assumed that the Y axis coincides with the normal line of the outer peripheral surface 13 of the pipe 1 passing through the center point C of the array sensor 10 and the center point O of the pipe 1. As shown in FIG. 3A, if the contact state between the curved surface 12 of the shoe 11 of the probe 4 and the outer peripheral surface 13 of the pipe 1 is good, the detection accuracy and reliability can be improved.

  However, the contact state between the curved surface 12 of the shoe 11 of the probe 4 and the outer peripheral surface 13 of the pipe 1 is not good as shown in FIG. The right edge of the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 are in contact with each other, but the left edge of the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 are not in contact with each other. If this is formed, a deviation occurs in the refraction angle and path length of the ultrasonic wave, and the detection accuracy and reliability are lowered.

Therefore, in the present embodiment, the computer 7 includes a contact state determination unit 25 and a contact state control unit 26. The contact state determination unit 25 reads part of the waveform data acquired at the same probe position from the data recording unit 22 of the transmission / reception unit 6, and based on this, the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1. It is determined whether the contact state is good (details will be described later). For example, when it is determined that the contact state is good, the waveform data acquired at the same probe position including the waveform data that is the determination material is finally stored in the data storage unit 27. Yes.

On the other hand, for example, when it is determined that the contact state is not good, a contact state adjustment command is output. In response to this command, the contact state control unit 26 outputs a rotation command for the support shaft 17 to the probe scanning mechanism 5 to rotate the support shaft 17. Thereby, the inclination of the probe 4 with respect to the outer peripheral surface 13 of the pipe 1 is adjusted, and the contact state between the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 is adjusted. Thereafter, the contact state control unit 26 outputs the above-described electronic scanning command to the delay time control unit 21. That is, sector electronic scanning is re-executed.

  Next, the ultrasonic flaw detection method of this embodiment will be described with reference to FIG. FIG. 4 is a flowchart for explaining the procedure of the ultrasonic flaw detection method in the present embodiment.

  In step S101, the inspector installs the probe scanning mechanism 5 and the probe 4. Specifically, first, the rail 15 constituting the probe scanning mechanism 5 is attached to the outer peripheral side of the pipe 1 using the fixing jig 14. At this time, the rail 15 is attached so that the center thereof is the same as the center O of the pipe 1. Thereafter, the probe 4 is attached together with other components constituting the probe scanning mechanism 5. At this time, preferably, the probe 4 is attached at an arbitrary position while visually checking the contact state between the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1. If necessary, the contact shaft 17 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 are adjusted by rotating the support shaft 17 of the probe scanning mechanism 5.

  In step S102, the inspector displays a setting input screen (not shown) on the display unit 9, and the flaw detection conditions (for example, flaw detection sensitivity, pulse voltage, probe moving pitch, etc.) and the inspection conditions. (For example, the dimensions of the pipe, the inspection region for focusing the ultrasonic beam, the control range of the beam transmission angle, etc.) are input by the input unit 8. Then, the computer 7 calculates and sets a delay pattern corresponding to each beam transmission angle based on the inspection condition and the like.

  Proceeding to step S103, the inspection of the pipe 1 is started. First, the position control unit 23 of the computer 7 outputs an electronic scanning command to the transmission / reception unit 6. The transmission / reception unit 6 performs sector electronic scanning that changes the beam transmission angle using the delay pattern described above, acquires waveform data for each beam transmission angle, and records the waveform data in the data recording unit 22. Then, the calculation / analysis unit 24 of the computer 7 generates a flaw detection image based on the waveform data acquired by the transmission / reception unit 6. The display unit 9 displays flaw detection images and waveform data at an arbitrary beam transmission angle.

  In step S <b> 104, the contact state determination unit 25 of the computer 7 extracts a part of the waveform data acquired by the transmission / reception unit 6. Specifically, when the beam transmission angle in the Y-axis direction is set to 0 degree, a positive beam transmission angle and a negative beam transmission angle having the same absolute value are set in advance, and these positive beam transmission angle and Waveform data of multiple reflected waves from the inner peripheral surface 2 of the pipe 1 at a negative beam transmission angle is extracted.

  For easy understanding, a flaw detection image (see FIG. 5A) when the contact state between the curved surface 12 of the shoe 11 of the probe 4 and the outer peripheral surface 13 of the pipe 1 is good (see FIG. 3A). ), The waveform data (see FIG. 5B) at the virtual refraction angle θm (specifically, for example, −5 degrees) corresponding to the negative beam transmission angle and the positive beam transmission angle. Waveform data (see FIG. 5B) at the virtual refraction angle θn (specifically, for example, +5 degrees) is extracted. Further, a description will be given using a flaw detection image (see FIG. 6A) when the contact state between the curved surface 12 of the shoe 11 of the probe 4 and the outer peripheral surface 13 of the pipe 1 is not good (see FIG. 3B). Similarly, waveform data at a virtual refraction angle θm corresponding to a negative beam transmission angle (see FIG. 6B) and waveform data at a virtual refraction angle θn corresponding to a positive beam transmission angle (see FIG. 6B). ).

  The waveform data shown in FIG. 5 (b) and FIG. 6 (b) are the first reflected wave (in other words, the reflected wave reflected only once by the inner peripheral surface 2 of the pipe 1), the second reflected wave ( In other words, the inner peripheral surface 2 of the pipe 1 → the outer peripheral surface 13 → the reflected wave reflected by the inner peripheral surface 2, and the third reflected wave (in other words, the inner peripheral surface 2 of the pipe 1 → the outer peripheral surface 13 → the inner periphery) Surface 2 → outer peripheral surface 13 → reflected wave reflected on inner peripheral surface 2), fourth reflected wave (in other words, inner peripheral surface 2 → outer peripheral surface 13 → inner peripheral surface 2 → outer peripheral surface 13 → inner of pipe 1) (Reflected wave reflected by peripheral surface 2 → outer peripheral surface 13 → inner peripheral surface 2).

  Proceeding to steps S105 and S106, the contact state determination unit 25 determines whether the contact state between the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 is good by comparing the extracted waveform data with each other. To do.

  In the case shown in FIG. 5B, the intensity M1 of the first reflected wave (specifically, the intensity in the corresponding path range) with respect to the waveform data at the negative beam transmission angle (that is, the corresponding virtual refraction angle θm). The same is applied to the following. The second reflected wave intensity M2, the third reflected wave intensity M3, and the fourth reflected wave intensity M4 are extracted. For the waveform data at the positive beam transmission angle (ie, the corresponding virtual refraction angle θn), the first reflected wave intensity N1, the second reflected wave intensity N2, the third reflected wave intensity N3, And the intensity N4 of the fourth reflected wave is extracted. And among the combinations (M1, N1), (M2, N2), (M3, N4), (M4, N4) of the corresponding reflected wave intensities, the one that does not reach the upper limit and is relatively large is selected. . In this case, since the strengths M1 and N1 reach the upper limit value, a combination of strengths (M2, N2) is selected. Then, by calculating the intensity difference | M2-N2 | and determining whether this difference | M2-N2 | is smaller than a predetermined threshold (specifically, for example, 10% of the intensity M2 or N2). It is determined whether or not the contact state between the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 is good.

  In this case, since the difference in intensity | M2-N2 | is smaller than a predetermined threshold value, it is determined that the contact state between the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 is good. Thereby, determination of step S106 is satisfy | filled and it moves to step S107. In step S <b> 107, the waveform data acquired by the transmission / reception unit 6 is stored in the data storage unit 27.

  On the other hand, in the case of FIG. 6B, the intensity of the first reflected wave M1 ′ and the intensity of the second reflected wave with respect to the waveform data at the negative beam transmission angle (that is, the corresponding virtual refraction angle θm). M2 ′, the intensity M3 ′ of the third reflected wave, and the intensity M4 ′ of the fourth reflected wave are extracted. For the waveform data at the positive beam transmission angle (that is, the corresponding virtual refraction angle θn), the first reflected wave intensity N1 ′, the second reflected wave intensity N2 ′, and the third reflected wave intensity. N3 ′ and the intensity N4 ′ of the fourth reflected wave are extracted. And among the combinations (M1 ′, N1 ′), (M2 ′, N2 ′), (M3 ′, N4 ′), (M4 ′, N4 ′) of the corresponding reflected wave intensities, the upper limit value has not been reached. And select a relatively large one. In this case, since the intensity N1 'has reached the upper limit value, a combination of intensity (M2', N2 ') is selected. Then, the intensity difference | M2′−N2 ′ | is calculated, and it is determined whether or not the difference | M2′−N2 ′ | is smaller than a predetermined threshold (for example, 10% of the intensity M2 ′ or N2 ′). Thus, it is determined whether or not the contact state between the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 is good.

In this case, since the intensity difference | M2′−N2 ′ | is larger than a predetermined threshold value, it is determined that the contact state between the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 is not good. Thereby, determination of step S106 is not satisfy | filled but it moves to step S108. In step S108, the contact state determination unit 25 outputs a contact state adjustment command according to the magnitude relationship between the intensity difference | M2′−N2 ′ | and the intensities M2 ′ and N2 ′. In response to this command, the contact state control unit 26 outputs a rotation command for the support shaft 17 to the probe scanning mechanism 5 to rotate the support shaft 17. Thereby, the inclination of the probe 4 with respect to the outer peripheral surface 13 of the pipe 1 is adjusted, and the contact state between the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 is adjusted.

  Thereafter, the process proceeds to step S <b> 103, and the contact state control unit 26 outputs an electronic scanning command to the transmission / reception unit 6. As a result, the transmission / reception unit 6 re-executes sector electronic scanning, re-acquires waveform data for each beam transmission angle, and rewrites the data recording unit 22.

  Then, after the above-described steps S104 and S105, if the determination in step S106 is satisfied, the process proceeds to step S107. In step S <b> 107, the waveform data reacquired by the transmission / reception unit 6 is stored in the data storage unit 27.

  After the completion of step S107, the process proceeds to step S109, and the position control unit 23 determines whether or not the inspection of all inspection points has been completed. If the inspection of all the inspection locations has not been completed, the determination at step S109 is not satisfied, and the routine goes to step S110. In step 110, the position control unit 23 outputs a movement command for the moving body 16 to the probe scanning mechanism 5 to move the moving body 16. That is, the probe 4 is moved to change the inspection location.

  Thereafter, the process proceeds to step S <b> 103, and the position control unit 23 outputs an electronic scanning command to the transmission / reception unit 6. As a result, the transmission / reception unit 6 performs sector electronic scanning, acquires waveform data for each beam transmission angle, and records the waveform data in the data recording unit 22. Thereafter, the same procedure as above is repeated.

  Then, when the inspection of all the inspection points is completed, the determination in step S109 is satisfied and the inspection ends.

  In the present embodiment as described above, it is determined whether or not the contact state between the curved surface 12 of the shoe 11 and the outer peripheral surface 13 of the pipe 1 is good, and the waveform is determined when the contact state is determined to be good. Save the data. On the other hand, when it is determined that the contact state is not good, the contact state is adjusted and sector electronic scanning is performed again. Therefore, detection accuracy and reliability can be improved.

  In the above-described embodiment, the waveform data of the multiple reflected waves at the negative beam transmission angle and the positive transmission angle are extracted, and the extracted waveform data is compared with each other, whereby the curved surface 12 of the shoe 11 and the pipe 1 are compared. The case of determining whether or not the contact state with the outer peripheral surface 13 is good has been described as an example. However, the present invention is not limited to this, and can be modified without departing from the spirit and technical idea of the present invention. . That is, not only waveform data at a negative beam transmission angle (ie, corresponding to the virtual refraction angle θm) and a positive beam transmission angle (ie, the virtual refraction angle θm), but also a beam transmission angle of 0 degree (ie, a virtual refraction angle of 0). Waveform data (see FIG. 5B and FIG. 6B) may also be extracted. Then, by comparing the waveform data at the negative beam transmission angle and the beam transmission angle of 0 degrees, and comparing the waveform data at the negative beam transmission angle and the beam transmission angle of 0 degrees, the curved surface 12 of the shoe 11 and the pipe 1 are compared. You may determine whether a contact state with the outer peripheral surface 13 is favorable. In this case, the same effect as described above can be obtained.

  In the above embodiment, the case where the plurality of piezoelectric elements 18 are arranged only in the circumferential direction of the pipe 1 has been described as an example. However, the present invention is not limited to this, and the scope and spirit of the present invention are not deviated. It can be deformed. That is, a plurality of rows of piezoelectric elements 18 may be arranged not only in the circumferential direction of the pipe 1 but also in the axial direction of the pipe 1. The beam transmission angle may be changed not only in the circumferential direction of the pipe 1 but also in the axial direction of the pipe 1. In such a case, the same effect as described above can be obtained.

DESCRIPTION OF SYMBOLS 1 Piping 4 Ultrasonic flaw detection probe 5 Probe scanning mechanism 6 Transmission / reception part 10 Array sensor 11 Shoe 12 Curved surface 13 Outer peripheral surface 18 Piezoelectric element 25 Contact state determination part 27 Data storage part

Claims (6)

A shoe having a curved surface in contact with the outer peripheral surface of the pipe, and an array sensor having a plurality of piezoelectric elements arranged in the circumferential direction of the pipe, and extending from the array sensor through the shoe toward the circumferential direction of the pipe. An ultrasonic flaw detection probe that transmits a sound wave beam and receives a reflected wave; and
A probe scanning mechanism capable of moving the probe in the circumferential direction of the pipe and adjusting the contact state between the curved surface of the shoe and the outer circumferential surface of the pipe;
A transmission / reception unit that performs sector electronic scanning that changes the beam transmission angle at an arbitrary probe position, and acquires waveform data of a reflected wave for each beam transmission angle;
By extracting waveform data of multiple reflected waves at at least two beam transmission angles from waveform data acquired at an arbitrary probe position, and comparing the extracted waveform data with each other, the curved surface of the shoe and the outer peripheral surface of the pipe A contact state determination unit that determines whether or not the contact state is good,
The contact state determination unit
When it is determined that the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is good, the waveform data acquired at an arbitrary probe position is stored in the data storage unit,
On the other hand, if it is determined that the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is not good, the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is adjusted by the probe scanning mechanism, An ultrasonic flaw detection apparatus wherein sector electronic scanning is re-executed by the transmission / reception unit. The ultrasonic flaw detector according to claim 1,
When the beam transmission angle for transmitting ultrasonic waves in the normal direction of the curved surface of the shoe passing through the center point of the array sensor is set to 0 degrees, the contact state determination unit is a positive value having an equal preset absolute value. Extracting the waveform data of multiple reflected waves at the beam transmission angle and the negative beam transmission angle, calculating the difference in the intensity of the reflected waves corresponding to each other, and determining whether this difference is smaller than a predetermined threshold Thus, it is determined whether or not the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is good. The ultrasonic flaw detector according to claim 2,
The probe scanning mechanism adjusts the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe by adjusting the inclination of the probe with respect to the outer peripheral surface of the pipe according to the difference. Sonic flaw detector. Using an ultrasonic flaw detection probe comprising a shoe having a curved surface in contact with the outer peripheral surface of a pipe and an array sensor having a plurality of piezoelectric elements arranged in the circumferential direction of the pipe, the pipe from the array sensor through the shoe An ultrasonic flaw detection method for transmitting an ultrasonic beam toward the circumferential direction and receiving a reflected wave,
Execute sector electronic scanning to change the beam transmission angle at an arbitrary probe position, acquire waveform data of reflected waves for each beam transmission angle,
By extracting waveform data of multiple reflected waves at at least two beam transmission angles from waveform data acquired at an arbitrary probe position, and comparing the extracted waveform data with each other, the curved surface of the shoe and the outer peripheral surface of the pipe Whether or not the contact state is good,
When it is determined that the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is good, the waveform data acquired at an arbitrary probe position is stored in the data storage unit,
On the other hand, when it is determined that the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is not good, the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe is adjusted, and then the sector electronic scan is performed again. An ultrasonic flaw detection method characterized by performing. The ultrasonic flaw detection method according to claim 4,
A positive beam transmission angle and a negative beam having a preset absolute value equal to each other when a beam transmission angle for transmitting ultrasonic waves in the normal direction of the curved surface of the shoe passing through the center point of the array sensor is 0 degree. By extracting the waveform data of the multiple reflected waves at the transmission angle, calculating the difference in the intensity of the reflected waves corresponding to each other, and determining whether this difference is smaller than a predetermined threshold, the curved surface of the shoe The ultrasonic flaw detection method characterized by determining whether the contact state with the outer peripheral surface of the said piping is favorable. The ultrasonic flaw detection method according to claim 5,
The ultrasonic flaw detection method characterized by adjusting the contact state between the curved surface of the shoe and the outer peripheral surface of the pipe by adjusting the inclination of the probe with respect to the outer peripheral surface of the pipe according to the difference.

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