Ultrasonic flaw detector apparatus and ultrasonic flaw-detection method

• US 6,092,420 A
• Filed: 06/17/1997
• Issued: 07/25/2000
• Est. Priority Date: 03/28/1996
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kimura, Tomonori, Koike, Mitsuhiro, Kameyama, Shumpei, Wadaka, Shusou, Manome, Yuuichi
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): Kwok, Helen C.
• Application Number:
  US08/860,277
• Time in Patent Office: 1,134 Days
• Field of Search: 73/599, 73/602, 73/618, 73/619, 73/620, 73/624, 73/627, 73/628, 73/1.82
• US Class Current: 73/620
• CPC Class Codes: G01N 2291/015 Attenuation, scattering
• CPC Class Codes: G01N 2291/0421 Longitudinal waves
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/056 Angular incidence, angular propagation
• CPC Class Codes: G01N 2291/101 one transducer
• CPC Class Codes: G01N 2291/2675 Seam, butt welding
• CPC Class Codes: G01N 29/043 in the interior, e.g. by shear waves
• CPC Class Codes: G01N 29/069 Defect imaging, localisation and sizing using, e.g. time of flight diffraction [TOFD], synthetic aperture focusing technique [SAFT], Amplituden-Laufzeit-Ortskurven [ALOK] technique
• CPC Class Codes: G01N 29/2487 Directing probes, e.g. angle probes directing arrangements G01N29/221
• CPC Class Codes: G01N 29/265 by moving the sensor relative to a stationary material
• CPC Class Codes: G01N 29/38 by time filtering, e.g. using time gates
• CPC Class Codes: G01N 29/48 by amplitude comparison
• CPC Class Codes: G01S 15/8906 Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques

Abstract

An ultrasonic flaw detection apparatus is equipped with a probe which is driven by a transmission signal and which transmits an ultrasonic pulse at an angle with respect to a surface of a test object. The probe receives an ultrasonic pulse, which has been reflected by a defect in the test object, as an echo. The apparatus further includes a scanner for scanning the probe over a predetermined scanning zone on the test object and for outputting a spatial position of the probe. The apparatus is further equipped with a transmitter-receiver which has a transmitter for generating a transmission signal and outputting the transmission signal to the probe, a position detector for receiving a spatial position of the probe from the scanner, and a signal processor for detecting the defect according to the stored spatial position of the probe and the stored echo, taking the spread of an ultrasonic beam attributable to diffraction into account. The apparatus makes it possible to improve the accuracy of an examination based on an ultrasonic wave through a test object, and also to improve the capability of detection and the accuracy of measurement of the shape, size, position, etc. of an acoustically disconnected portion (defect).

Claims

1. An ultrasonic flaw detection apparatus comprising:

a probe which transmits an ultrasonic pulse at an angle with respect to a test surface of a test object and receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

scanning means for scanning said probe over a predetermined scanning zone on said test object and outputting a spatial position of said probe; and

detecting means which

accepts and stores said echo from said probe, and accepts and stores a spatial position of said probe from said scanning means, and

detects said acoustically discontinued portion according to the spatial position of said probe and said echo, considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued portion,

wherein said probe is driven by a transmission signal to transmit said ultrasonic pulse at a transmitting angle with respect to a test surface of a test object, and receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo at a receiving angle, which is different from said transmitting angle, with respect to said test surface.

2. An ultrasonic flaw detection apparatus comprising:

a probe which transmits an ultrasonic pulse at an angle with respect to a test surface of a test object and receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

scanning means for scanning said probe over a predetermined scanning zone on said test object and outputting a spatial position of said probe; and

detecting means which

accepts and stores said echo from said probe, and accepts and stores a spatial position of said probe from said scanning means, and

detects said acoustically discontinued portion according to the spatial position of said probe and said echo, considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued portion,

wherein said probe is driven by a transmission signal to transmit said ultrasonic pulse at a transmitting angle with respect to a test surface of a test object, and receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo at a receiving angle, which is identical to said transmitting angle, with respect to said test surface.

3. An ultrasonic flaw detection apparatus comprising:

a probe which transmits an ultrasonic pulse at an angle with respect to a test surface of a test object and receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

scanning means for scanning said probe over a predetermined scanning zone on said test object and outputting a spatial position of said probe; and

detecting means which

accepts and stores said echo from said probe, and accepts and stores a spatial position of said probe from said scanning means, and

detects said acoustically discontinued portion according to the spatial position of said probe and said echo, considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued portion

wherein said detecting means includes;

transmitting means for generating a transmission signal and outputting said transmission signal to said probe;

receiving means for accepting said received echo from said probe;

position detecting means for receiving a spatial position of said probe from said scanning means; and

signal processing means for detecting said acoustically discontinued portion according to said stored spatial position of the probe and said stored echo, taking the spread of an ultrasonic beam attributable to diffraction into account.

4. An ultrasonic flaw detection apparatus according to claim 3, wherein said signal processing means includes:

raw data storing means for storing an echo received when said probe was scanned over a predetermined scanning zone, and coordinates of said probe corresponding to when said ultrasonic pulse was transmitted and when said echo was received;

candidate path identifying means for identifying a candidate of a transmitting and receiving round trip beam propagation path, which lies in an effective beam width of said probe, according to a fixed reconstruction point in a fixed image reconstruction zone of said test object and the coordinates of said probe stored in said raw data storing means;

amplitude adding means for determining the time at which an echo is to be received, obtaining the amplitude of an echo corresponding to said time from said raw data storing means, and adding each obtained echo amplitude on each candidate of said transmitting and receiving round trip beam propagation path; and

image reconstruction means for outputting a value, which is obtained by adding said echo amplitudes over a fixed scanning zone of said probe, as a reconstructed image at said fixed reconstruction point.

5. An ultrasonic flaw detection apparatus according to claim 4, wherein said signal processing means outputs a reconstructed image at a fixed reconstruction point in said image reconstruction zone as a three-dimensional image.

6. An ultrasonic flaw detection apparatus according to claim 4 wherein, when the amplitude of the echo corresponding to said determined time has a significant value, said amplitude adding means adds said amplitude.

7. An ultrasonic flaw detection apparatus according to claim 4, wherein said effective beam width is a beam width of -3 dB.

8. An ultrasonic flaw detection apparatus according to claim 3, wherein

said probe comprises a transmitting probe connected to said transmitting means and a receiving probe connected to said receiving means, and

said scanning means comprises a transmission scanner provided for said transmitting probe and a reception scanner provided for said receiving probe.

9. An ultrasonic flaw detection apparatus comprising:

a probe which transmits an ultrasonic pulse at an angle with respect to a test surface of a test object and receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

a scanning means for scanning said probe over a predetermined scanning zone on said test object and outputting a spatial position of said probe; and

detecting means for

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe from said scanning means, and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo, considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstructed point are combined to indicate said acoustically discontinued portion, and further considering a mode conversion from a longitudinal wave to a transverse wave and a mode conversion from a transverse wave to a longitudinal wave when said ultrasonic pulse is reflected,

wherein said probe is driven by a transmission signal to transmit said ultrasonic pulse at a transmitting angle with respect to a test surface of a test object, and receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo at a receiving angle, which is different from said transmitting angle, with respect to said test surface.

10. An ultrasonic flaw detection apparatus comprising:

a probe which transmits an ultrasonic pulse at an angle with respect to a test surface of a test object and receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

a scanning means for scanning said probe over a predetermined scanning zone on said test object and outputting a spatial position of said probe; and

detecting means for

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe from said scanning means, and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo, considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstructed point are combined to indicate said acoustically discontinued portion, and further considering a mode conversion from a longitudinal wave to a transverse wave and a mode conversion from a transverse wave to a longitudinal wave when said ultrasonic pulse is reflected,

wherein said probe is driven by a transmission signal to transmit an ultrasonic pulse at a transmitting angle with respect to a test surface of a test object, and receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo at a receiving angle, which is identical to said transmitting angle, with respect to said test surface.

11. An ultrasonic flaw detection apparatus comprising:

a probe which transmits an ultrasonic pulse at an angle with respect to a test surface of a test object and receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

a scanning means for scanning said probe over a predetermined scanning zone on said test object and outputting a spatial position of said probe; and

detecting means for

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe from said scanning means, and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo, considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstructed point are combined to indicate said acoustically discontinued portion, and further considering a mode conversion from a longitudinal wave to a transverse wave and a mode conversion from a transverse wave to a longitudinal wave when said ultrasonic pulse is reflected,

wherein said detecting means includes;

transmitting means for generating a transmission signal and outputting said transmission signal to said probe,

receiving means for accepting said received echo from said probe;

position detecting means for receiving a spatial position of said probe from said scanning means; and

signal processing means for detecting said acoustically discontinued portion according to said stored spatial position of the probe and said stored echo, considering the spread of an ultrasonic beam due to diffraction and a mode conversion from a longitudinal wave to a transverse wave and a mode conversion from a transverse wave to a longitudinal wave when said ultrasonic pulse is reflected.

12. An ultrasonic flaw detection apparatus according to claim 11, wherein said signal processing means includes:

raw data storing means for storing an echo received when said probe was scanned over a predetermined scanning zone, and the coordinates of said probe when said ultrasonic pulse was transmitted and when said echo was received;

candidate path identifying means for identifying a candidate of a transmitting and receiving round trip beam propagation path, which lies in an effective beam width of said probe, according to a fixed reconstruction point in a fixed image reconstruction zone of said test object and the coordinates of said probe stored in said raw data storing means;

amplitude adding means for determining the time at which an echo is to be received, obtaining the amplitude of an echo corresponding to said time from said raw data storing means, and adding each obtained echo amplitude on each candidate of said transmitting and receiving round trip beam propagation path; and

image reconstruction means for outputting a value, which is obtained by adding said echo amplitudes over a fixed scanning zone of said probe, as a reconstructed image at said fixed reconstruction point.

13. An ultrasonic flaw detection apparatus according to claim 12, wherein said signal processing means outputs a reconstructed image at a fixed reconstruction point in said image reconstruction zone as a three-dimensional image.

14. An ultrasonic flaw detection apparatus according to claim 12 wherein, when the amplitude of the echo corresponding to said determined time has a significant value, said amplitude adding means adds said amplitude.

15. An ultrasonic flaw detection apparatus according to claim 12, wherein said effective beam width is a beam width of -3 dB of an ultrasonic beam related to a transverse wave.

16. An ultrasonic flaw detection apparatus according to claim 12, wherein said effective beam width is a beam width of -3 dB of an ultrasonic beam related to a longitudinal wave.

17. An ultrasonic flaw detection apparatus according to claim 11, wherein

said probe comprises a transmitting probe connected to said transmitting means and a receiving probe connected to said receiving means, and

said scanning means comprises a transmission scanner provided for said transmitting probe and a reception scanner provided for said receiving probe.

18. An ultrasonic flaw detection method comprising:

scanning a probe over a predetermined scanning zone on a test object;

transmitting an ultrasonic pulse from said probe at an angle with respect to a test surface of said test object;

receiving, at said probe, said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe; and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued portion, wherein

said transmitting step generates a transmission signal and outputs said transmission signal to said probe, then transmits an ultrasonic pulse at a transmitting angle with respect to a test surface of said test object, and

said receiving step receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo at a receiving angle, which is different from said transmitting angle, with respect to said test surface.

19. An ultrasonic flaw detection method comprising:

scanning a probe over a predetermined scanning zone on a test object;

transmitting an ultrasonic pulse from said probe at an angle with respect to a test surface of said test object;

receiving, at said probe, said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe; and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued portion, wherein

said transmitting step generates a transmission signal and outputs said transmission signal to said probe, then transmits an ultrasonic pulse at a transmitting angle with respect to a test surface of said test object, and

said receiving step receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo at a receiving angle, which is identical to said transmitting angle, with respect to said test surface.

20. An ultrasonic flaw detection method comprising:

scanning a probe over a predetermined scanning zone on a test object;

transmitting an ultrasonic pulse from said probe at an angle with respect to a test surface of said test object;

receiving, at said probe, said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe; and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued portion,

wherein said storing step stores an echo received when said probe was scanned over a predetermined scanning zone, and the coordinates of said probe when said ultrasonic pulse was transmitted and when said echo was received; and

said detecting step includes the steps of;

identifying a candidate of a transmitting and receiving round trip beam propagation path which lies in an effective beam width of said probe according to a fixed reconstruction point in a fixed image reconstruction zone of said test object and said stored coordinates of said probe,

determining the time at which an echo is to be received, obtaining the amplitude of an echo corresponding to said time, and adding each obtained echo amplitude on each candidate of said transmitting and receiving round trip beam propagation path; and

outputting a value, which is obtained by adding said echo amplitude over a fixed scanning zone of said probe, as a reconstructed image at said fixed reconstruction point.

21. An ultrasonic flaw detection method according to claim 20, wherein said detecting step outputs a reconstructed image at a fixed reconstruction point in said image reconstruction zone as a three-dimensional image.

22. An ultrasonic flaw detection method according to claim 20 wherein, when the amplitude of the echo corresponding to said determined time has a significant value, said amplitude adding step adds said amplitude.

23. An ultrasonic flaw detection method according to claim 20, wherein said effective beam width is a beam width of -3 dB.

24. An ultrasonic flaw detection method comprising:

scanning a probe over a predetermined scanning zone on a test object;

transmitting an ultrasonic pulse from said probe at an angle with respect to a test surface of said test object;

receiving, at said probe, said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe; and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued portion, wherein

said probe comprises a transmitting probe and a receiving probe,

said scanning step is performed by a scanning means which comprises a transmission scanner provided for said transmitting probe and a reception scanner provided for said receiving probe, and

the spatial position of said ultrasonic pulse transmitted by said transmitting probe is different from the spatial position of said echo received by said receiving probe.

25. An ultrasonic flaw detection method comprising:

scanning a probe over a predetermined scanning zone on a test object;

transmitting an ultrasonic pulse from said probe at an angle with respect to a test surface of said test object;

receiving said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe when said ultrasonic pulse was transmitted and when said echo was received; and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo, considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued point, and further considering a mode conversion from a longitudinal wave to a transverse wave and a mode conversion from a transverse wave to a longitudinal wave which take place when said ultrasonic pulse is reflected, wherein

said transmitting step generates a transmission signal and outputs said transmission signal to said probe, then transmits an ultrasonic pulse at a transmitting angle with respect to a test surface of said test object, and

said receiving step receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo at a receiving angle, which is different from said transmitting angle, with respect to said test surface.

26. An ultrasonic flaw detection method comprising:

scanning a probe over a predetermined scanning zone on a test object;

transmitting an ultrasonic pulse from said probe at an angle with respect to a test surface of said test object;

receiving said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe when said ultrasonic pulse was transmitted and when said echo was received; and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo, considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued point, and further considering a mode conversion from a longitudinal wave to a transverse wave and a mode conversion from a transverse wave to a longitudinal wave which take place when said ultrasonic pulse is reflected, wherein

said transmitting step generates a transmission signal and outputs said transmission signal to said probe, then transmits an ultrasonic pulse at a transmitting angle with respect to a test surface of said test object, and

said receiving step receives said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo at a receiving angle, which is identical to said transmitting angle, with respect to said test surface.

27. An ultrasonic flaw detection method comprising:

scanning a probe over a predetermined scanning zone on a test object;

transmitting an ultrasonic pulse from said probe at an angle with respect to a test surface of said test object;

receiving said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe when said ultrasonic pulse was transmitted and when said echo was received; and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo, considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued point, and further considering a mode conversion from a longitudinal wave to a transverse wave and a mode conversion from a transverse wave to a longitudinal wave which take place when said ultrasonic pulse is reflected,

wherein said storing step stores an echo received when said probe was scanned over a predetermined scanning zone, and the coordinates of said probe when said ultrasonic pulse was transmitted and when said echo was received; and

said detecting step includes the steps of;

identifying a candidate of a transmitting and receiving round trip beam propagation path which lies in an effective beam width of said probe according to a fixed reconstruction point in a fixed image reconstruction zone of said test object and said stored coordinates of said probe,

determining the time at which an echo is to be received, obtaining the amplitude of an echo corresponding to said time, and adding each obtained echo amplitude on each candidate of said transmitting and receiving round trip beam path; and

outputting a value, which is obtained by adding said echo amplitude over a fixed scanning zone of said probe, as a reconstructed image at said fixed reconstruction point.

28. An ultrasonic flaw detection method according to claim 27, wherein said detecting step outputs a reconstructed image at a fixed reconstruction point in said image reconstruction zone as a three-dimensional image.

29. An ultrasonic flaw detection method according to claim 27 wherein, when the amplitude of the echo corresponding to said determined time has a significant value, said amplitude adding step adds said amplitude.

30. An ultrasonic flaw detection method according to claim 27, wherein said effective beam width is a beam width of -3 dB of an ultrasonic beam related to a transverse wave.

31. An ultrasonic flaw detection method according to claim 27, wherein said effective beam width is a beam width of -3 dB of an ultrasonic beam related to a longitudinal wave.

32. An ultrasonic flaw detection method comprising:

scanning a probe over a predetermined scanning zone on a test object;

transmitting an ultrasonic pulse from said probe at an angle with respect to a test surface of said test object;

receiving said ultrasonic pulse, which has been reflected by an acoustically discontinued portion in said test object, as an echo;

accepting and storing said received echo from said probe, and receiving and storing the spatial position of said probe when said ultrasonic pulse was transmitted and when said echo was received; and

detecting said acoustically discontinued portion according to the spatial position of said probe and said echo, considering the spread of an ultrasonic beam attributable to diffraction so that values for multiple propagation paths between an origin and a reconstruction point are combined to indicate said acoustically discontinued point, and further considering a mode conversion from a longitudinal wave to a transverse wave and a mode conversion from a transverse wave to a longitudinal wave which take place when said ultrasonic pulse is reflected, wherein

said probe comprises a transmitting probe and a receiving probe, and said scanning step is performed by a scanning means which comprises a transmitting scanner provided for said transmitting probe and a reception scanner provided for said receiving probe, and

the spatial position of said ultrasonic pulse transmitted by said transmitting probe is different from the spatial position of said echo received by said receiving probe.