Non-destructive testing device, method and program

Abstract

To provide a nondestructive inspection technology capable of easily detecting an internal flaw of a resin coating part by an ultrasonic wave flaw detection test.SOLUTION: A nondestructive inspection device 10 includes: a transmission unit 17 that oscillates an oscillator 25 provided in a probe 27 to transmit an ultrasonic beam 26; a reception unit 18 that receives an echo waveform 20 of the ultrasonic beam 26 made incident to a resin layer 30 coated on a regular uneven structure 31; a first authentication unit 11 that authenticates, as first reference signals 21, those derived from an incidence surface 32 of the resin layer 30, of the echo waveforms 20; a second authentication unit 12 that authenticates, as second reference signals 22 derived from the uneven structure 31, those being at a depth position common to each other in the resin layer 30 and regularly received in a surface direction, of the echo waveforms 20; and an extraction unit 13 that extracts, as a flaw signals 23, those received in a beam path length 28 held between the first reference signal 21 and the second reference signal 22, of the echo waveforms 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a non-destructive inspection technique using ultrasonic flaw detection testing. [Background technology]

[0002] To reduce friction, the metal surfaces of axle sliding surfaces in power plants are coated with materials such as white metal, PEEK (polyether ether ketone), and PTFE (polytetrafluoroethylene).Anomalies in these axle sliding surfaces are typically detected by detecting the presence or absence of abnormal noises that occur due to shaft vibration.

[0003] If an abnormality occurs in the axle sliding surface, the plant will only be shut down and action taken once an abnormal noise or other problem is detected. For this reason, in order to improve the reliability and availability of power plants, it is important to inspect the coating parts regularly to ensure their integrity.

[0004] Currently, inspection of coatings on axle sliding surfaces is limited to surface observation, and internal observation is not generally performed. This is because the probability of defects occurring inside the coating is considered low. On the other hand, a known technique for observing coatings is disclosed, which uses a scanning ultrasonic probe to predict wear at the joint surface between a boss and a bush of large rotating equipment from the reflection of ultrasonic waves before an abnormal condition occurs. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-227935 Summary of the Invention [Problem to be solved by the invention]

[0006] Ultrasonic testing or radiographic testing can be considered to inspect the entire coating on the axle sliding surface. However, due to structural constraints and the shape, it is difficult to apply radiographic testing, so the application of ultrasonic testing is being considered.

[0007] However, when applying ultrasonic flaw detection testing to coated parts, the following problems arise: (1) The thickness of the coated part is only a few millimeters, so the influence of multiple echoes is significant; (2) When applying angle beam testing, the sound speed of resin materials is slower than that of metal materials, making flaw detection testing difficult; and (3) The coated part has a complex structure because it is bonded to the metal surface.

[0008] The above-mentioned known technology using a scanning ultrasonic probe determines the state of separation at the joining surface between the boss and bushing from the reflected strength of ultrasonic waves. However, this known technology only determines the state of the contact surface of the coating portion, and it is difficult to detect internal defects.

[0009] The embodiments of the present invention have been made in consideration of the above circumstances, and aim to provide a non-destructive testing technique that can easily detect internal defects in resin-coated portions using ultrasonic flaw detection testing. [Means for solving the problem]

[0010] In the non-destructive inspection device according to the embodiment, the device comprises a transmitting unit that causes a vibrator provided on a probe to oscillate and transmit an ultrasonic beam; a receiving unit that receives an echo waveform of the ultrasonic beam incident on a resin layer coated with a regular uneven structure; a first identification unit that identifies, among the echo waveforms, those originating from the incident surface of the resin layer as first reference signals; a second identification unit that identifies, among the echo waveforms, those that are received regularly in the surface direction at a common depth position in the resin layer as second reference signals originating from the uneven structure; and an extraction unit that extracts, among the echo waveforms, those received in a beam path sandwiched between the first reference signal and the second reference signal as defect signals. [Effects of the Invention]

[0011] According to an embodiment of the present invention, a non-destructive testing technique is provided that can easily detect internal defects in a resin-coated portion by ultrasonic flaw detection testing. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram of a non-destructive testing device that performs ultrasonic flaw detection testing on a resin layer coated with a regular uneven structure in a first embodiment of the present invention. [Figure 2] Cross-sectional image showing the results of ultrasonic testing of a resin layer. [Figure 3] 1 is a graph showing the echo waveform of an ultrasonic beam, with the horizontal axis representing the propagation time of the beam path and the vertical axis representing the intensity. [Figure 4] FIG. 1 is a perspective view of a punched metal that forms a regular uneven structure on the axle sliding surface. [Figure 5] FIG. 10 is a block diagram of a non-destructive testing device for performing ultrasonic flaw detection testing on a resin layer coated with a regular uneven structure in a second embodiment. [Figure 6] 3 is a flowchart illustrating the steps of a nondestructive inspection method according to an embodiment and an algorithm of a nondestructive inspection program. DETAILED DESCRIPTION OF THE INVENTION

[0013] (First embodiment) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a block diagram of a non-destructive testing device 10A (10) according to a first embodiment of the present invention, which performs ultrasonic testing on a resin layer 30 coated with a regular uneven structure 31. Fig. 2 is a cross-sectional image showing the results of ultrasonic testing on the resin layer 30. Fig. 3 is a graph showing an echo waveform 20 of an ultrasonic beam 26, with the horizontal axis representing the propagation time of the beam path 35(A) to (I) and the vertical axis representing intensity.

[0014] As shown in Figure 1, the non-destructive testing device 10 includes a transmitting unit 17 that oscillates a vibrator 25 provided on a probe 27 to transmit an ultrasonic beam 26, a receiving unit 18 that receives an echo waveform 20 of the ultrasonic beam 26 incident on a resin layer 30 coated with a regular uneven structure 31, a first identification unit 11 that identifies the echo waveform 20 originating from the incident surface 32 of the resin layer 30 as a first reference signal 21, a second identification unit 12 that identifies the echo waveform 20 that has a common depth position in the resin layer 30 and is received regularly in the surface direction as a second reference signal 22 originating from the uneven structure 31, and an extraction unit 13 that extracts the echo waveform 20 received on a beam path 28 sandwiched between the first reference signal 21 and the second reference signal 22 as a defect signal 23.

[0015] Non-destructive testing using an ultrasonic beam 26 is widely used to evaluate defects, voids, peeling at joints, and other conditions within structures or parts being inspected. The echo waveform 20, which is the reflection of the ultrasonic beam 26 incident on the resin layer 30 being inspected, originates from three sources: the surface (incident surface 32) of the resin layer 30, the defect 33, and the interface (uneven structure 31). Detecting the defect 33 requires processing to focus on and extract the defect signal 23 from the echo waveform 20. Then, by detecting the intensity and timing of the defect signal 23 originating from this defect, information such as the position and size of the defect 33 in the resin layer 30 being inspected is visualized.

[0016] The probe 27 is made up of a vibrator 25 made of a piezoelectric element and a wedge-shaped shoe 29, and is placed in close contact with the surface (incident surface 32) of the resin layer 30 to be inspected, via an acoustic couplant (not shown), which is a liquid acoustic medium. The propagation speed of the ultrasonic beam 26 in the resin layer 30 is slower than that of general metals. For this reason, the material constituting the wedge-shaped shoe 29 is preferably a case in which a liquid or gel-like acoustic medium is sealed, or a resin molded body (whether or not it is made of the same material as the resin layer 30).

[0017] High-precision nondestructive testing using angle beam testing can be achieved by using a material for the wedge-shaped shoe 29 that has a sound velocity similar to that of the resin layer 30. When PTFE (polytetrafluoroethylene; longitudinal wave sound velocity: 1490 m / s) is used for the resin layer 30, it is preferable to use a gel-like acoustic medium (sound velocity: 1410 m / s) for the shoe 29. In addition, in the first embodiment, the probe 27 is designed to perform flaw detection over a wide area of ​​the resin layer 30 by manually scanning the incident surface 32.

[0018] The transmitter 17 oscillates the transducer 25 provided on the probe 27 to transmit an ultrasonic beam 26. When the ultrasonic beam 26 is incident on the resin layer 30 in this manner, the first reference signal 21 is reflected by the incident surface 32, and the second reference signal 22 is reflected by the uneven structure 31. If a defect 33 exists in the beam path 35, the beam is reflected there and detected by the transducer 25 as a defect signal 23.

[0019] The receiving unit 18 (FIG. 1) receives the echo waveform 20 that is output by the transducer 25 after detecting the reflection of the ultrasonic beam 26. The echo waveform 20 that is output as a weak analog signal from the transducer 25 is received by the receiving unit 18, amplified, and then converted into a digital signal.

[0020] The first identification unit 11 identifies the echo waveform 20 that originates from the incident surface 32 of the resin layer 30 as the first reference signal 21. Specifically, after the oscillator 25 is oscillated, the first signal detected in the echo waveform 20 is identified as the first reference signal 21.

[0021] The second identification unit 12 identifies, among the echo waveforms 20, those that are received regularly in the surface direction at a common depth position in the resin layer 30 as second reference signals 22 originating from the concave-convex structure 31. The second reference signal 22 observed in the concave-convex structure 31 such as a perforated metal (FIG. 4) has double peaks in the echo waveform 20 as shown in the figure due to a slight time lag between reflections from the corners of the upper surface and reflections from the corners of the lower surface. The second reference signal 22 can also be identified based on such double peaks.

[0022] The extraction unit 13 sets the boundary of the first reference signal 21 of the echo waveform 20 to the incident surface 32 of the resin layer 30, and sets the boundary of the second reference signal 22 to the interface with the concave-convex structure 31. Then, it extracts a defect signal 23 detected in a region sandwiched between both ends of the boundary set in the beam path 28. This makes it possible to detect defects 33 in the resin layer 30 with high sensitivity without being affected by noise such as reflection from the concave-convex structure 31.

[0023] The imaging unit 19 generates a cross-sectional image along the depth direction of the resin layer 30 or a perspective image from the incident surface 32 based on the defect signal 23. That is, it displays an echo waveform 20 (FIG. 3) generally called an A-scope, a cross-sectional image of the resin layer 30 called a B-scope (FIG. 2), and a planar perspective image of the resin layer 30 called a C-scope (not shown). To obtain the images of FIGS. 2 and 3, a scanning means (not shown) for the probe 27 and a position recognition means (not shown) for identifying the starting points of each beam path 35(A) to (I) are required.

[0024] 4 is a perspective view of a perforated metal that forms a regular uneven structure 31 on the axle sliding surface. On the axle sliding surface, perforated metal or wire is bonded onto a steel material, and a resin layer 30 is further coated on top of that. By coating on such a regular uneven structure 31, peeling of the resin layer 30 due to sliding, etc. is suppressed.

[0025] Although punched metal is used as an example of the regular uneven structure 31 for coating the resin layer 30, the present invention is not limited to this. As long as the surface to be bonded to the coating material has a regular uneven shape, structures such as regularly arranged wires are also applicable. Furthermore, examples of materials for the resin layer 30 include PTFE (polytetrafluoroethylene), but this is not particularly limited.

[0026] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is a block diagram of a nondestructive testing device 10B(10) that performs ultrasonic flaw detection testing on a resin layer 30 coated with a regular uneven structure 31 in the second embodiment.

[0027] The non-destructive inspection device 10B of the second embodiment has a configuration in which at least one of an electronic scanning unit 16 and a mechanical scanning unit 14 is further added to the configuration of the first embodiment described above. In the second embodiment, the probe 27 automatically performs flaw detection over a wide area of ​​the resin layer 30 by electronically and mechanically scanning the incident surface 32. In Fig. 5, parts having the same configuration or function as those in Fig. 1 are indicated by the same reference numerals, and duplicated explanations will be omitted.

[0028] The probe 27 of the second embodiment has a plurality of transducers 25 arranged in a linear or matrix array. By adjusting the delay time of the oscillation timing of adjacent transducers 25, the incident direction and focal length of the ultrasonic beam 26 can be set arbitrarily. Then, the setting unit 15 sets the scanning conditions such as the incident direction.

[0029] The electronic scanning unit 16 adjusts such oscillation timing to scan the ultrasonic beam 26 emitted from the array of transducers 25. The electronic scanning unit 16 also calculates a delay time for the oscillation timing of the transducers 25 based on input from the setting unit 15. The transmitting unit 17 transmits a pulse signal 36 to each transducer 25 based on the delay time calculated by the electronic scanning unit 16 to cause it to oscillate.

[0030] The mechanical scanning unit 14 scans the ultrasonic beam 26 by mechanically moving the probe 27. The probe 27 is connected to a driving unit 37 that mechanically moves along the incident surface 32. The driving unit 37 scans the probe 27 on the incident surface 32 based on a driving signal 38 transmitted from the mechanical scanning unit 14. Although the probe 27 is shown moving only one-dimensionally in the figure, it can also be moved two-dimensionally.

[0031] In the second embodiment, the ultrasonic beam 26 can be scanned by mechanically moving a probe 27 provided with a single transducer 25 instead of an array.

[0032] The steps of the nondestructive inspection method according to the embodiment and the algorithm of the nondestructive inspection program will be described with reference to the flowchart in Fig. 6 (see Figs. 1 and 5 as appropriate). First, the transducer 25 provided on the probe 27 in contact with the incident surface 32 is oscillated (S11), and an ultrasonic beam 26 is transmitted (S12). Then, the echo waveform 20 reflected by the ultrasonic beam 26 incident on the resin layer 30 is received (S13).

[0033] Next, among the echo waveforms 20, those originating from the incident surface 32 of the resin layer 30 are recognized as first reference signals 21 (S14). Then, among the echo waveforms 20, those received at a common depth position in the resin layer 30 and regularly in the surface direction are recognized as second reference signals 22 originating from the uneven structure 31 (S15). Furthermore, among the echo waveforms 20, those received in a beam path 28 sandwiched between the first reference signal 21 and the second reference signal 22 are extracted as defect signals 23 (S16). Then, a longitudinal cross-sectional image or a planar perspective image of the resin layer 30 is imaged based on the defect signals 23 (S17, END).

[0034] According to at least one of the embodiments of the non-destructive testing device described above, by recognizing that signals received regularly in the surface direction at a common depth position among the echo waveforms obtained by ultrasonic flaw detection testing originate from the uneven structure of the interface, it becomes possible to easily detect internal defects in the resin coating portion.

[0035] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as the inventions described in the claims and their equivalents.

[0036] The non-destructive testing device described above includes a control device with a highly integrated processor such as a dedicated chip, FPGA (Field Programmable Gate Array), GPU (Graphics Processing Unit), or CPU (Central Processing Unit), a storage device such as ROM (Read Only Memory) or RAM (Random Access Memory), an external storage device such as HDD (Hard Disk Drive) or SSD (Solid State Drive), a display device such as a monitor, input devices such as a mouse and keyboard, and a communication I / F, and can be realized with a hardware configuration using a normal computer. Therefore, the components of the non-destructive testing device can also be realized by a computer processor and can be operated by a non-destructive testing program.

[0037] The non-destructive testing program may be provided by being pre-installed in a ROM, etc. Alternatively, the program may be provided by being stored in an installable or executable file format on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD, or flexible disk (FD).

[0038] The nondestructive inspection program according to this embodiment may be stored on a computer connected to a network such as the Internet and provided by downloading it via the network. The nondestructive inspection device may also be configured by combining separate modules that independently perform the functions of the components and are interconnected via a network or dedicated lines. [Explanation of symbols]

[0039] 10...Non-destructive testing device, 11...First certification unit, 12...Second certification unit, 13...Extraction unit, 14...Mechanical scanning unit, 15...Setting unit, 16...Electronic scanning unit, 17...Transmitting unit, 18...Receiving unit, 19...Imaging unit, 20...Echo waveform, 21...First reference signal, 22...Second reference signal, 23...Defect signal, 25...Transducer, 26...Ultrasonic beam, 27...Probe, 28...Beam path, 29...Shoe, 30...Resin layer, 31...Uneven structure, 32...Incident surface, 33...Defect, 35...Beam path, 36...Pulse signal, 37...Drive unit, 38...Drive signal.

Claims

1. a transmitter that oscillates a transducer provided in the probe to transmit an ultrasonic beam; a receiving unit that receives an echo waveform of the ultrasonic beam that is incident on a resin layer coated with a regular uneven structure; a first determination unit that determines, among the echo waveforms, a waveform originating from the incident surface of the resin layer as a first reference signal; a second identification unit that identifies, among the echo waveforms, those that are received at a common depth position in the resin layer and are regularly received in a surface direction as second reference signals derived from the uneven structure; an extractor that extracts, from the echo waveform, one received in a beam path between the first reference signal and the second reference signal as a defect signal.

2. 2. The non-destructive inspection device according to claim 1, A non-destructive testing device comprising an electronic scanning unit that scans the ultrasonic beam by adjusting the oscillation timing of each of the plurality of transducers arranged in an array.

3. 3. The non-destructive inspection device according to claim 1 or 2, A non-destructive testing device comprising a mechanical scanning unit that moves the probe to scan the ultrasonic beam.

4. 4. The non-destructive inspection device according to claim 3, A non-destructive inspection device including an imaging unit that generates a cross-sectional image along the depth direction of the resin layer or a perspective image from the incident surface based on the defect signal.

5. a step of oscillating a transducer provided in the probe to transmit an ultrasonic beam; receiving an echo waveform of the ultrasonic beam incident on a resin layer coated with a regular uneven structure; identifying, among the echo waveforms, one originating from the incident surface of the resin layer as a first reference signal; a step of identifying, among the echo waveforms, those received regularly in a surface direction at a common depth position in the resin layer as second reference signals derived from the concavo-convex structure; and extracting, from the echo waveforms, those received in a beam path between the first reference signal and the second reference signal as defect signals.

6. 6. The non-destructive inspection method according to claim 5, A non-destructive inspection method in which the regular uneven structure is formed on the sliding surface of an axle.

7. On the computer, a step of oscillating a transducer provided in the probe to transmit an ultrasonic beam; receiving an echo waveform of the ultrasonic beam incident on a resin layer coated with a regular uneven structure; identifying, among the echo waveforms, one originating from the incident surface of the resin layer as a first reference signal; a step of identifying, among the echo waveforms, those received regularly in a surface direction at a common depth position in the resin layer as second reference signals derived from the concavo-convex structure; extracting, from the echo waveforms, those received in a beam path between the first reference signal and the second reference signal as defect signals.

Images