Ultrasonic flaw-detection device and ultrasonic flaw-detection method

Abstract

This ultrasonic flaw-detection device performs ultrasonic flaw-detection from the inside of an annular inner peripheral surface of a flaw-detection target object having the whole circumference or a part of the annular inner peripheral surface. The ultrasonic flaw-detection device comprises: a probe unit having a first ultrasonic probe and a second ultrasonic probe; and a rotary unit for relatively rotating the flaw-detection target object with respect to the probe unit around the central axis of the inner peripheral surface of the flaw-detection target object. The first ultrasonic probe has a first ultrasonic vibrator that radiates ultrasonic waves from the central axis toward the inner peripheral surface, and the second ultrasonic probe has a second ultrasonic vibrator that radiates ultrasonic waves in a direction different from that of the first ultrasonic vibrator from the central axis toward the inner peripheral surface. When viewed from the direction of the central axis, the probe unit is configured such that the static first irradiation range angle of the first ultrasonic vibrator is different from the static second irradiation range angle of the second ultrasonic vibrator.

Description

Ultrasonic flaw detection device and ultrasonic flaw detection method

[0001] The present disclosure relates to an ultrasonic inspection apparatus and an ultrasonic inspection method.

[0002] A known flaw detector is an ultrasonic flaw detector, such as that disclosed in Patent Document 1. The ultrasonic flaw detector is a non-destructive testing device that uses ultrasonic waves to detect defects inside an object.

[0003] Japanese Patent Application Laid-Open No. 2002-22714

[0004] Flaw detection in objects with complex shapes can be difficult due to interference from reflected ultrasonic waves. For this reason, CT inspection using X-rays is performed on objects with complex shapes. When CT inspection is performed on large parts made of metal with a high X-ray attenuation coefficient, the area to be inspected is so thick that the X-rays do not penetrate sufficiently, making it impossible to perform the inspection. In such cases, CT inspection using high-energy X-rays is required. However, the introduction costs of CT devices using high-energy X-rays are enormous, making them difficult to introduce.

[0005] An object of the present disclosure is to provide an ultrasonic flaw detection device and an ultrasonic flaw detection method that can perform ultrasonic flaw detection even on a thick object to be detected.

[0006] An ultrasonic flaw detection device according to the present disclosure performs ultrasonic flaw detection from inside the inner circumferential surface of an object to be detected, the object having an entire or partial annular inner circumferential surface. The ultrasonic flaw detection device includes a probe unit having a first ultrasonic probe and a second ultrasonic probe, and a rotation unit that rotates the object to be detected relative to the probe unit around the central axis of the inner circumferential surface of the object to be detected. The first ultrasonic probe has a first ultrasonic vibrator that irradiates ultrasonic waves from the central axis toward the inner circumferential surface, and the second ultrasonic probe has a second ultrasonic vibrator that irradiates ultrasonic waves from the central axis toward the inner circumferential surface in a direction different from that of the first ultrasonic vibrator. The probe unit is configured such that, when viewed from the direction of the central axis, a static first irradiation range angle of the first ultrasonic vibrator is different from a static second irradiation range angle of the second ultrasonic vibrator.

[0007] The probe unit may be configured such that the first irradiation range angle and the second irradiation range angle are different from each other by making the curvature of a first vibration surface on which the first ultrasonic vibrator is provided different from the curvature of a second vibration surface on which the second ultrasonic vibrator is provided.

[0008] An ultrasonic flaw detection method according to the present disclosure uses the ultrasonic flaw detection device described above. In the ultrasonic flaw detection method, the probe unit is disposed on the central axis of the inner circumferential surface, and the inspection object is rotated around the central axis relative to the probe unit by the rotation unit, while ultrasonic waves are irradiated onto the inner circumferential surface from the first ultrasonic probe and the second ultrasonic probe to perform flaw detection.

[0009] Ultrasonic waves may be simultaneously emitted from the first ultrasonic probe and the second ultrasonic probe toward the inner surface of the object to be inspected, which has an annular inner surface around the entire circumference, while the object to be inspected is rotated around the central axis relative to the probe unit to perform inspection.

[0010] The object to be inspected may be a product manufactured by a metal additive manufacturing method.

[0011] According to the ultrasonic flaw detection device or ultrasonic flaw detection method of the present disclosure, ultrasonic flaw detection can be performed even on a thick object to be detected.

[0012] Fig. 1 is a schematic perspective view showing the configuration of an ultrasonic flaw detection device according to an embodiment. Fig. 2 is a schematic plan view of the device. Fig. 3 is a schematic perspective view of a first ultrasonic probe of the device. Fig. 4 is a schematic perspective view of a second ultrasonic probe of the device.

[0013] Hereinafter, an ultrasonic flaw detection device according to an embodiment will be described with reference to the drawings.

[0014] As shown in FIG. 1 , an ultrasonic testing device (hereinafter simply referred to as the "device") tests an annular object W to be tested. A hole H is formed in the center of the object W to be tested, and ultrasonic waves are irradiated from the inside of the hole H toward an inner peripheral surface P to test the flaws. In this embodiment, the object W to be tested has a completely annular shape, and ultrasonic testing is performed along the entire circumference of the inner peripheral surface P. However, the object W to be tested may also have a partial annular shape, for example, a semi-annular shape. In this case, the inner peripheral surface P only has a portion of the entire circumference, i.e., half the circumference, and ultrasonic testing may be performed along only this half circumference. The object W to be tested is placed in a couplant, i.e., a water tank (not shown) filled with water as a contact medium.

[0015] The flaw detection target W in this embodiment is a product manufactured by metal additive manufacturing (MAM). MAM is a manufacturing method capable of producing products with complex shapes. However, in FIGS. 1 and 2, only the annular shape is shown for simplicity. Products manufactured by MAM may have defects specific to MAM, such as incomplete fusion of the metal powder. Such incompletely fused portions are also subject to flaw detection. Since incompletely fused portions are formed by voids filled with metal powder, the volume of the voids is small and the intensity of the ultrasonic echo is low, making them difficult to detect using ultrasonic testing. MAM is performed, for example, using a 3D printer, and includes the powder bed fusion (PBF) method using the metal powder described above, as well as direct energy deposition (DED) and fused deposition modeling (FDM).

[0016] The device includes a probe unit 1 that transmits ultrasonic waves and receives their reflected waves. The probe unit 1 has a pair of a first ultrasonic probe 11 and a second ultrasonic probe 12. The first ultrasonic probe 11 and the second ultrasonic probe 12 each transmit ultrasonic waves and receive their reflected waves. The first ultrasonic probe 11 and the second ultrasonic probe 12 are attached to the tip of a rod 2 and are oriented in opposite directions. During flaw detection, the rod 2 is positioned so as to coincide with the central axis X of the inner circumferential surface P, and is rotated around the central axis X by a rotation unit 3, which will be described later. The rotation of the rod 2 rotates the probe unit 1 around the central axis X inside the object W to be detected. That is, the first ultrasonic probe 11 and the second ultrasonic probe 12 are simultaneously rotated around the central axis X.

[0017] The rotation unit 3 described above includes a motor 31, which is a drive source for rotating the rod 2, and a control unit 32 that controls the motor 31. The motor 31 is connected to the control unit 32. The rotation of the motor 31, i.e., the rotation of the probe unit 1, is controlled by the control unit 32. The control unit 32 also controls the entire device. The control unit 32 is a computer, and includes a central processing unit (CPU) that performs calculations, storage that stores an operation system, a flaw detection program, etc., memory used during calculations, a signal input / output device, a monitor, etc.

[0018] The probe unit 1, i.e., the first ultrasonic probe 11 and the second ultrasonic probe 12, are also connected to the control unit 32 via the connection line 4. Power is supplied to the first ultrasonic probe 11 and the second ultrasonic probe 12 from the control unit 32 via the connection line 4. The control unit 32 also transmits and receives signals to and from the first ultrasonic probe 11 and the second ultrasonic probe 12 via the connection line 4. That is, the control unit 32 controls the ultrasonic transmission of the first ultrasonic probe 11 and the second ultrasonic probe 12, and receives detection results from the first ultrasonic probe 11 and the second ultrasonic probe 12. Furthermore, the control unit 32 post-processes the received detection results to generate data for flaw detection and displays the generated data on a monitor or the like. The control unit 32 may itself determine the presence or absence of a flaw and output the determination result.

[0019] As indicated by the dotted arrow in FIG. 2 , the first ultrasonic probe 11 has a first ultrasonic vibrator 11A on a first vibration surface 11P that radiates ultrasonic waves from the central axis X toward the inner circumferential surface P. Similarly, the second ultrasonic probe 12 has a second ultrasonic vibrator 12A on a second vibration surface 12P that radiates ultrasonic waves from the central axis X toward the inner circumferential surface P. As described above, the first ultrasonic probe 11 and the second ultrasonic probe 12 are oriented in opposite directions. That is, the first vibration surface 11P (see FIG. 3 ) on which the first ultrasonic vibrator 11A is provided and the second vibration surface 12P (see FIG. 4 ) on which the second ultrasonic vibrator 12A is provided are oriented in opposite directions. Therefore, the second ultrasonic vibrator 12A emits ultrasonic waves in a direction different from the direction in which the first ultrasonic vibrator 11A emits ultrasonic waves, that is, in this embodiment, in a direction 180 degrees different about the central axis X.

[0020] As shown in FIG. 2 , the probe unit 1 is configured so that the static first irradiation range angle of the first ultrasonic transducer 11A and the static second irradiation range angle of the second ultrasonic transducer 12A are different when observed from the direction of the central axis X. In this embodiment, the first irradiation range angle is set so that the ultrasonic waves emitted from the first vibration surface 11P are diffused. On the other hand, the second irradiation range angle is set so that the ultrasonic waves emitted from the second vibration surface 12P are converged. In this embodiment, as shown in FIGS. 3 and 4 , these irradiation range angles are mechanically made different by making the curvatures of the vibration surfaces 11P and 12P different. As shown in FIG. 3 , the first vibration surface 11P of the first ultrasonic probe 11 is convexly curved, and the second vibration surface 12P of the second ultrasonic probe 12 is concavely curved.

[0021] The "static" irradiation range angle here refers to the irradiation angle of ultrasonic waves from the first ultrasonic probe 11 and the second ultrasonic probe 12 when they are not rotated, and is one of the values ​​related to the directional characteristics of the ultrasonic sensor. The "static" irradiation range angle may be, for example, the so-called "sound pressure half-angle." During flaw detection, the first ultrasonic probe 11 and the second ultrasonic probe 12 are rotated to irradiate ultrasonic waves toward the inner circumferential surface P. The "static" irradiation range angle differs from the "dynamic" irradiation angle during this rotational scanning. When an ultrasonic probe having a "static" irradiation range angle is rotated, the "static" irradiation range angle also moves in the rotational direction, thereby expanding the irradiation range. The "dynamic" irradiation range angle refers to the irradiation range angle including the range expansion due to the rotational movement of the "static" irradiation range angle.

[0022] In this embodiment, the first irradiation range angle of the first ultrasonic probe 11 is set to diffuse ultrasonic waves, and as shown in FIG. 2, the first ultrasonic probe 11 detects a defect S1 located deep from the inner circumferential surface P. That is, the inspection range of the first ultrasonic probe 11 is a deep position from the inner circumferential surface P. On the other hand, the second irradiation range angle of the second ultrasonic probe 12 is set to converge ultrasonic waves, and as shown in FIG. 2, the second ultrasonic probe 12 detects a defect S2 located shallow from the inner circumferential surface P. That is, the inspection range of the second ultrasonic probe 12 is a shallow position from the inner circumferential surface P. The ultrasonic waves are refracted even on the surface of the inner circumferential surface P to reach the targeted inspection depth. In this way, because the inspection depths of the first ultrasonic probe 11 and the second ultrasonic probe 12 are different, inspection can be performed even if the inspection target W is thick in the ultrasonic wave transmission direction.

[0023] In this embodiment, as shown in Fig. 3, a plurality of first ultrasonic transducers 11A are provided along the central axis X on the first vibration surface 11P of the first ultrasonic probe 11. Similarly, as shown in Fig. 4, a plurality of second ultrasonic transducers 12A are provided along the central axis X on the second vibration surface 12P of the second ultrasonic probe 12. In other words, each of the ultrasonic probes 11 and 12 is a linear array probe. By arranging the plurality of ultrasonic transducers 11A and 12A side by side in this manner, flaw detection can be performed using the aperture synthesis method described below.

[0024] In this embodiment, the probe unit 1 is rotated around the central axis X inside the object to be detected W by the rotation unit 3, but the object to be detected W may also be rotated around the probe unit 1, i.e., around the central axis X. In this case, the rotation unit 3 rotates the object to be detected W. For example, the object to be detected W is placed on a turntable, and the rotation unit 3 rotates the turntable. That is, the rotation unit 3 rotates the object to be detected W "relatively" to the probe unit 1. In this case, only the object to be detected W may be rotated, or only the probe unit 1 may be rotated. Alternatively, the object to be detected W may be rotated "relatively" to the probe unit 1 by rotating both the object to be detected W and the probe unit 1 around the central axis X at different rotational speeds.

[0025] Prior to flaw detection, calibration is performed in advance using a calibration block in place of the test object W. Examples of the calibration block include a block with drilled holes simulating normal defects or a block manufactured by metal additive manufacturing with intentionally formed incompletely melted portions. Furthermore, during flaw detection of the test object W, the probe unit 1 is positioned on the central axis X of the inner circumferential surface P. Here, before rotational scanning of the probe unit 1, fine adjustments are also made to the distances between the first ultrasonic probe 11 and the second ultrasonic probe 12 and the inner circumferential surface P. Although not shown, a mechanism for finely adjusting the distance between the first vibration surface 11P of the first ultrasonic probe 11 and the inner circumferential surface P is provided between the first ultrasonic probe 11 and the rod 2 or inside the first ultrasonic probe 11. A similar fine adjustment mechanism is also provided in the second ultrasonic probe 12.

[0026] Thereafter, the object W to be detected is rotated about the central axis X by the rotation unit 3 relative to the probe unit 1, and ultrasonic waves are irradiated onto the inner peripheral surface P from the first ultrasonic probe 11 and the second ultrasonic probe 12 to perform flaw detection, i.e., rotational scanning. The first ultrasonic probe 11 acquires data for flaw detection in a deep portion from the inner peripheral surface P by the ultrasonic waves transmitted from the first ultrasonic probe 11. The second ultrasonic probe 12 acquires data for flaw detection in a shallow portion from the inner peripheral surface P by the ultrasonic waves transmitted from the second ultrasonic probe 12.

[0027] In this embodiment, the first ultrasonic probe 11 and the second ultrasonic probe 12 face in opposite directions, and are therefore less susceptible to the influence of the ultrasonic waves emitted by each probe and the ultrasonic echoes that are the reflected waves. Furthermore, in this embodiment, the object W to be detected has a completely annular shape. Ultrasonic waves are simultaneously irradiated from the rotating first ultrasonic probe 11 and the second ultrasonic probe 12 toward the entire circumference of the annular inner peripheral surface P. Therefore, by rotating the object W to be detected once around the central axis X relative to the probe unit 1, inspection of the entire circumference of the inner peripheral surface P is completed by both the first ultrasonic probe 11 and the second ultrasonic probe 12.

[0028] When scanning continues along the direction of the central axis X, the object W to be detected is moved by one pass in the direction of the central axis X relative to the probe unit 1, and then rotational scanning is performed. Thereafter, axial feeding and rotational scanning are performed alternately. Data acquired by the probe unit 1, i.e., the first ultrasonic probe 11 and the second ultrasonic probe 12, is post-processed by the control unit 32. As described above, the ultrasonic probes 11 and 12 of this embodiment are linear array probes having multiple ultrasonic transducers 11A and 12A, respectively, along the central axis X. In rotational scanning, the ultrasonic transducers 11A and 12A, which are linear array probes, are effectively utilized. Specifically, detection and data processing are performed using an aperture synthesis method.

[0029] Although the aperture synthesis method itself is a known technique, flaw detection can be performed suitably by using it in this embodiment. For example, flaw detection can be performed using the FMC / TFM algorithm or the PWI algorithm, which are aperture synthesis methods. By correcting the sensitivity of data acquired using the aperture synthesis method using these algorithms, more accurate flaw detection can be performed, and in particular, flaw detection of insufficient fusion in products manufactured by metal additive manufacturing can be performed very suitably. Calibration using the calibration block described above is effective for flaw detection using this aperture synthesis method.

[0030] In the ultrasonic flaw detection device according to the above embodiment, ultrasonic flaw detection is performed from inside the inner circumferential surface P of the annular object W to be detected. The device includes a probe unit 1 having a first ultrasonic probe 11 and a second ultrasonic probe 12. The device also includes a rotation unit 3 that rotates the object W to be detected relative to the probe unit 1 about the central axis X of the inner circumferential surface P of the object W to be detected. The first ultrasonic probe 11 has a first ultrasonic vibrator 11A that irradiates ultrasonic waves from the central axis X toward the inner circumferential surface P. The second ultrasonic probe 12 has a second ultrasonic vibrator 12A that irradiates ultrasonic waves from the central axis X toward the inner circumferential surface P in a direction different from that of the first ultrasonic vibrator 11A. When viewed from the direction of the central axis X, the probe unit 1 is configured such that the static first irradiation range angle of the first ultrasonic vibrator 11A is different from the static second irradiation range angle of the second ultrasonic vibrator 12A, as shown in FIG. 2 .

[0031] Therefore, while the rotation unit 3 rotates the test object W relative to the probe unit 1, the first ultrasonic probe 11 and the second ultrasonic probe 12 can simultaneously perform flaw detection. Here, the static first irradiation range angle of the first ultrasonic probe 11 and the static second irradiation range angle of the second ultrasonic probe 12 are different. Therefore, the ultrasonic probes 11 and 12 can detect flaws at different depths from the inner circumferential surface P, and can detect flaws over a wide range in the depth direction relative to the inner circumferential surface P, i.e., in the radial direction of the annular test object W. Furthermore, since the first ultrasonic probe 11 and the second ultrasonic probe 12 are simultaneously rotated to perform flaw detection at different depths, flaw detection can be completed in a short time. Therefore, the device according to the above embodiment can suitably perform ultrasonic flaw detection on a test object having a thick portion.

[0032] In the above embodiment, the probe unit 1 is configured such that the first irradiation range angle and the second irradiation range angle are different by differentiating the curvature of the first vibration surface 11P from the curvature of the second vibration surface 12P. Mechanically varying the irradiation range angle based on the curvature in this manner allows for efficient control of ultrasonic waves and stable transmission and reception of ultrasonic waves. To vary the irradiation range angle, ultrasonic transducers 11A and 12A may be arranged on the vibration surfaces 11P and 12P in a direction perpendicular to the central axis X to form a matrix probe, and the static irradiation range angle of the ultrasonic waves may be controlled by controlling the transmission of ultrasonic waves. However, this would complicate the control of the ultrasonic waves, so mechanically varying the irradiation range angle as in the above embodiment allows for the desired flaw detection to be achieved more inexpensively.

[0033] Furthermore, in the ultrasonic flaw detection method using the device of the above embodiment, the probe unit 1 is disposed on the central axis X of the annular inner peripheral surface P. Then, flaw detection is performed by irradiating ultrasonic waves from the first ultrasonic probe 11 and the second ultrasonic probe 12 onto the inner peripheral surface P while rotating the object W to be flaw detected about the central axis X relative to the probe unit 1 by the rotation unit 3. Therefore, as described above, flaw detection can be performed efficiently and in a short time on the entire circumference or part of the inner peripheral surface P of the annular object W to be flaw detected.

[0034] In particular, in the method of the above embodiment, flaws are detected along the entire circumference of the inner peripheral surface P of a completely annular object W to be detected, which has the entire circumference of the inner peripheral surface P. In this case, ultrasonic waves are simultaneously irradiated from the first ultrasonic probe 11 and the second ultrasonic probe 12 toward the inner peripheral surface P, while the object W to be detected is rotated once around the central axis X relative to the probe unit 1. Therefore, flaws can be efficiently detected at different depths along the entire circumference with just one rotation.

[0035] Furthermore, the flaw detection target W in the above embodiment was a product manufactured by metal additive manufacturing. As described above, products manufactured by metal additive manufacturing can have specific defects, such as incomplete fusion, that are difficult to detect. According to the method of the above embodiment, such defects can also be detected by flaw detection using the first ultrasonic probe 11 and the second ultrasonic probe 12.

[0036] Although several embodiments have been described, the embodiments can be modified or varied based on the above disclosure. All components of the above embodiments and all features described in the claims may be individually extracted and combined, unless they contradict each other.

[0037] For example, although the device of the above embodiment has two ultrasonic probes 11 and 12, it is not always necessary to simultaneously perform flaw detection using both ultrasonic probes 11 and 12. The control unit 32 may control the device so that flaw detection can be performed using only one of the two ultrasonic probes 11 and 12.

[0038] In the above embodiment, the ultrasonic probes 11 and 12 are oriented in opposite directions by 180 degrees. This is preferable because the ultrasonic waves emitted by each probe and the reflected ultrasonic echoes from each probe are less likely to be affected by each other. However, the angle between the ultrasonic probes 11 and 12 does not have to be 180 degrees as long as they are oriented in different directions.

[0039] In the above embodiment, the static first irradiation range angle of the first ultrasonic probe 11 is set to diverge ultrasonic waves, and the static second irradiation range of the second ultrasonic probe 12 is set to converge ultrasonic waves. However, this is not limited to this, and it is sufficient that the irradiation range angles are different. If the irradiation range angles are different, both may be divergent or both may be convergent. Alternatively, the irradiation range angle of one of the two may be divergent or convergent, and the irradiation range angle of the other may be parallel, neither divergent nor convergent. The irradiation ranges can be made parallel by making the first vibration surface 11P or the second vibration surface 12P a flat surface rather than a curved surface. If the irradiation range angles are different, different flaw detection depths can be achieved by the first ultrasonic probe 11 and the second ultrasonic probe 12.

[0040] The entire contents of Japanese Patent Application No. 2024-109052 (filed July 5, 2024) are incorporated herein by reference.

[0041] REFERENCE SIGNS LIST 1 probe unit 11 first ultrasonic probe 11A first ultrasonic vibrator 11P first vibration surface 12 second ultrasonic probe 12A second ultrasonic vibrator 12P second vibration surface 3 rotation unit W object to be inspected P inner peripheral surface X central axis

Claims

1. An ultrasonic flaw detection device for performing ultrasonic flaw detection from inside the inner surface of an object to be detected having an annular inner surface having a partial or entire circumference thereof, comprising: a probe unit having a first ultrasonic probe and a second ultrasonic probe; and a rotation unit for rotating the object to be detected relative to the probe unit around the central axis of the inner surface of the object to be detected, wherein the first ultrasonic probe has a first ultrasonic vibrator that irradiates ultrasonic waves from the central axis toward the inner surface, and the second ultrasonic probe has a second ultrasonic vibrator that irradiates ultrasonic waves from the central axis toward the inner surface in a direction different from that of the first ultrasonic vibrator, and the ultrasonic flaw detection device is configured such that, when viewed from the direction of the central axis, a static first irradiation range angle of the first ultrasonic vibrator is different from a static second irradiation range angle of the second ultrasonic vibrator.

2. An ultrasonic flaw detection device as described in claim 1, wherein the probe unit is configured so that the first irradiation range angle and the second irradiation range angle are different by making the curvature of the first vibration surface on which the first ultrasonic vibrator is provided different from the curvature of the second vibration surface on which the second ultrasonic vibrator is provided.

3. An ultrasonic flaw detection method using the ultrasonic flaw detection device described in claim 1, comprising: placing the probe unit on the central axis of the inner peripheral surface; rotating the object to be detected about the central axis relative to the probe unit using the rotation unit; and irradiating the inner peripheral surface with ultrasonic waves from the first ultrasonic probe and the second ultrasonic probe to perform flaw detection.

4. An ultrasonic flaw detection method as described in claim 3, wherein ultrasonic waves are simultaneously emitted from the first ultrasonic probe and the second ultrasonic probe toward the inner peripheral surface of the object to be detected, which has an annular inner peripheral surface having an entire circumference, while the object to be detected is rotated once around the central axis relative to the probe unit to perform flaw detection.

5. The ultrasonic flaw detection method according to claim 3 or 4, wherein the object to be detected is a product manufactured by a metal additive manufacturing method.

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