Ultrasonic flaw detector

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to an ultrasonic flaw detector, and is particularly useful when using a diffracted wave at a crack end to detect a flaw based on the propagation time of the diffracted wave.

【0002】

[Conventional technology]

The TOFD (Time of Flight Diffraction) method is known as a method for detecting defects such as cracks inside a subject such as a steel plate using diffracted waves. This TOFD method will be described with reference to FIG. As shown in the figure, the transmitting side ultrasonic probe 1 has one ultrasonic probe 2, and the ultrasonic probe 2 is fixed to the shoe 3 to have a predetermined incident angle. The ultrasonic waves are sent out toward the inside of the subject 4. The receiving side ultrasonic probe 5 has one ultrasonic probe 6 like the transmitting side ultrasonic probe 1, and the ultrasonic probe 6 is fixed to the shoe 7. , The ultrasonic waves propagating inside the subject 4 are received. The ultrasonic waves transmitted from the ultrasonic probe 2 diffuse and propagate in the subject 4, but when there is a defect 8 inside the subject 4, diffracted waves are generated corresponding to the upper and lower ends thereof.

【0003】

That is, the waveform of the ultrasonic wave received by the receiving side ultrasonic probe 5 at this time is the waveform shown in FIG. In Fig. 4, the horizontal axis is time, the vertical axis is the amplitude of the ultrasonic signal, and P.₁Surface wave (straight wave) propagated along the surface of subject 4, P₂Is the bottom reflected wave reflected from the bottom of subject 4, P₃Corresponds to the top edge of defect 8 in the diffracted wave and P₄Is the reflected wave corresponding to the lower end of defect 8.

【0004】

Therefore, the defect depth D shown in FIG. 3 is the defect upper end d.₁And the lower end of the defect d₂It can be obtained by the following equation (1) based on the position of.

【0005】

[Number 1]

<img file="JP2001228126A_D0001.tif" />【0006】

In the above TOFD method, as shown in FIG. 3, placing ultrasonic probes 2 and 6 on both sides of the defect 8 is an essential condition for the flaw detection, but the upper end of the defect 8 and the upper end of the defect 8 and Diffracted wave P at the bottom₃And diffracted wave P₄The propagation time of the defect 8 enables highly accurate detection of the defect depth D without being affected by the shape and inclination of the defect 8.

【0007】

[Problems to be Solved by the Invention]

However, in the above TOFD method, the diffracted wave P₃, P₄While the defect 8 is detected using the above, since the diffused wave is used for the transmission of the ultrasonic wave, the ultrasonic wave can be applied to the entire defect 8 at once, but the diffracted wave is correspondingly increased. P₃, P₄The amplitude of is small. Therefore, the diffracted wave P₃, P₄May be difficult to detect well.

【0008】

In view of the above prior art, the present invention provides an ultrasonic flaw detector capable of obtaining a diffracted wave having a large amplitude in ultrasonic flaw detection for detecting the defect depth by utilizing the diffracted waves at the upper and lower ends of the defect. The purpose.

【0009】

[Means for solving problems]

The configuration of the present invention that achieves the above object is characterized by the following points.

【0010】

1) The ultrasonic wave transmitted from the transmitting side ultrasonic probe is received by the receiving side ultrasonic probe via the subject, and the defect inside the subject is detected based on the waveform of the received ultrasonic wave. In the ultrasonic flaw detector, the transmitting side ultrasonic probe is composed of an aggregate of ultrasonic probes having an array structure in which a plurality of elements are arranged, and each ultrasonic probe of the transmitting side ultrasonic probe is composed of each ultrasonic probe. By sequentially delaying the transmission timing of the output ultrasonic waves, the ultrasonic beam transmitted from the transmitting side ultrasonic probe is converged and scanned. According to the present invention, the amplitude of the diffracted wave at the upper and lower ends of the internal defect of the subject can be increased, and the ultrasonic beam can be oscillated over the entire depth direction of the subject.

【0011】

2) The ultrasonic wave transmitted from the transmitting side ultrasonic probe is received by the receiving side ultrasonic probe via the subject, and the defect inside the subject is detected based on the waveform of the received ultrasonic wave. In the ultrasonic flaw detector, the receiving side ultrasonic probe is composed of an aggregate of ultrasonic probes in an array structure in which a plurality of elements are arranged, and each ultrasonic probe of the transmitting side ultrasonic probe constitutes the ultrasonic probe. By sequentially delaying the reception timing of ultrasonic waves, the ultrasonic beam transmitted and diffused by the transmitting side ultrasonic probe is effectively converged and scanned by each ultrasonic probe to be received. thing. According to the present invention, the amplitude of the diffracted wave at the upper and lower ends of the internal defect of the subject can be increased, and the ultrasonic beam can be oscillated over the entire depth direction of the subject.

【0012】

3) The ultrasonic wave transmitted from the transmitting side ultrasonic probe is received by the receiving side ultrasonic probe via the subject, and the flaw inside the subject is detected based on the waveform of the received ultrasonic wave. In the device, the transmitting side ultrasonic probe is composed of an aggregate of ultrasonic probes having an array structure in which a plurality of elements are arranged, and each ultrasonic probe of the transmitting side ultrasonic probe outputs. By sequentially delaying the transmission timing of ultrasonic waves, the ultrasonic beam transmitted from the transmitting side ultrasonic probe is converged and scanned, and an aggregate of ultrasonic probes having an array structure similar to that of the transmitting side. The receiving side ultrasonic probe is configured with, and the timing of receiving ultrasonic waves by each ultrasonic probe of this ultrasonic probe is synchronized with the transmitting side ultrasonic probe and transmitted by sequentially delaying. The ultrasonic beam transmitted by the side ultrasonic probe is effectively converged and scanned by each ultrasonic probe to be received. According to the present invention, the amplitude of the diffracted wave at the upper and lower ends of the internal defect of the subject can be increased, and the ultrasonic beam can be oscillated over the entire depth direction of the subject. Here, since the diffracted wave generated by the converged ultrasonic beam is received by effectively converging it, the diffraction having a larger amplitude than that of the inventions described in the above [Claim 1] and [Claim 2]. Can receive waves.

【0013】

4) In any one of the ultrasonic flaw detectors described in 1) to 3) above, a part of the ultrasonic probes constituting the ultrasonic probe is used for transmitting and / or receiving surface waves. In addition, the tip of the shoe of the ultrasonic probe is made of a material different from the surrounding members so that surface waves propagating on the surface of the subject can be transmitted and / or received. According to the present invention, it is possible to obtain a good surface wave as a reference when specifying the depth of the defect.

【0014】

5) The ultrasonic wave transmitted from the transmitting side ultrasonic probe is received by the receiving side ultrasonic probe via the subject, and the defect inside the subject is detected based on the waveform of the received ultrasonic wave. In the ultrasonic flaw detection method, the transmitting side ultrasonic probe is composed of an aggregate of ultrasonic probes having an array structure in which a plurality of elements are arranged, and each ultrasonic probe of the transmitting side ultrasonic probe is formed. By sequentially delaying the transmission timing of the output ultrasonic waves, the ultrasonic beam transmitted from the transmitting side ultrasonic probe is converged, and the incident angle of the center of the ultrasonic beam with respect to the subject is always 45 °. The ultrasonic probe was selected to send an ultrasonic beam. According to the present invention, it is possible to irradiate each position in the depth direction of the subject with an ultrasonic beam incident at 45 °.

【0015】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

【0016】

FIG. 1 is an explanatory diagram conceptually showing an ultrasonic probe according to an embodiment of the present invention. In addition, in the figure, the same part as FIG. As shown in FIG. 1, the transmitting side ultrasonic probe 11 is formed by supporting an aggregate of ultrasonic probes 12 having an array structure in which a plurality of elements are arranged by a shoe 13. Similar to the transmitting side ultrasonic probe 11, the receiving side ultrasonic probe 15 also has a shoe 17 supporting an aggregate of ultrasonic probes 16 having an array structure in which a plurality of elements are arranged. Here, the transmitting side ultrasonic probe 11 converges the ultrasonic beam B transmitted from the ultrasonic probe by sequentially delaying the transmission timing of the ultrasonic waves output by each ultrasonic probe 12. Let it scan as well as let it. That is, B in the figure₁, B₂, B₃Converge as shown in, and B₁From B₃Direction, also B₃From B₁It is designed to scan in the direction of. On the other hand, the receiving side ultrasonic probe 15 synchronizes the timing of receiving the ultrasonic beam B by each ultrasonic probe 16 with the corresponding ultrasonic probe 12 on the transmitting side and sequentially delays it. The ultrasonic beam B transmitted by the transmitting side ultrasonic probe 11 is effectively converged and scanned for reception. Thus, the diffracted wave P based on the ultrasonic beam B converged from the upper and lower ends of the defect 8.₃, P₄Is obtained. Such diffracted wave P₃, P₄Is diffused, but the ultrasonic probe 15 on the receiving side can effectively converge the ultrasonic beam at this time and scan it for reception. This is because each ultrasonic probe 16 is synchronized with the corresponding ultrasonic probe 12 on the transmitting side, and the reception timing of the ultrasonic beam B by each ultrasonic probe 16 is sequentially delayed for reception. is there.

【0017】

A reference position is needed to identify the depth of defect 8. The surface of subject 4 is usually used for this reference position. Therefore, the surface wave P propagating along the surface of the subject 4₁I need to make it. In this embodiment, a part of the ultrasonic probes 12 and 16 constituting the transmitting side and receiving side ultrasonic probe units 11 and 15 is surface wave P.₁The tips of the shoes 13 and 17 of the ultrasonic wave detectors 11 and 15 for transmission and reception, and for transmission and reception, are made of a material different from the surrounding members. More specifically, the opposing tips 13a and 17a of the shoes 13 and 17 are made of a material whose sound velocity is faster than the surrounding material, and a part of the ultrasonic beam B has a critical incident angle. Beyond surface wave P₁And this surface wave P₁Is input.

【0018】

Thus, according to the ultrasonic probe according to the present embodiment, the defect depth D can be detected by the same principle as the TOFD method according to the prior art. At this time, in this embodiment, the ultrasonic beam transmitted from the transmitting side ultrasonic probe 11 is converged, so that the diffracted wave P based on the upper and lower ends of the defect 8 is correspondingly converged.₃, P₄A large amplitude can be obtained. Moreover, this diffracted wave P₃, P₄Is detected by converging with the receiving side ultrasonic probe 15, so that the amplitude of the detected ultrasonic beam is also large. On the other hand, since the ultrasonic beam transmitted from the transmitting side ultrasonic probe 11 can be sequentially moved, it can be scanned in the thickness direction of the subject 8. Further, since the ultrasonic beam received by the receiving side ultrasonic probe 15 can be scanned in synchronization with this, the defect 8 can be detected over the entire area of the subject 4 in the thickness direction.

【0019】

In the above embodiment, both the transmitting side ultrasonic probe 12 and the receiving side ultrasonic probe 16 transmit and receive ultrasonic waves so that the ultrasonic beam B converges, and both of them send and receive ultrasonic waves. It was formed to scan, but it is not limited to this. Diffracted wave P obtained on the receiving side₃, P₄Although the amplitude of is slightly smaller, only the ultrasonic probe 12 on the transmitting side may be sent and scanned so that the ultrasonic beam B converges. At this time, the receiving side receives the diffused wave. Further, only the ultrasonic probe 16 on the receiving side may be received and scanned by converging the ultrasonic beam B. At this time, the transmitting side transmits a diffused wave.

【0020】

FIG. 2 is an explanatory diagram conceptually showing another embodiment of the present invention. As shown in the figure, in this embodiment, the transmitting side ultrasonic probe 21 is composed of an aggregate of ultrasonic probes 22 having an array structure in which a plurality of elements are arranged, and a similar ultrasonic probe is formed. The receiving side ultrasonic probe 25 is composed of 26 aggregates. Similar to the ultrasonic probe 12 in the embodiment shown in FIG. 1, these ultrasonic probes 22 converge and scan the ultrasonic beam B by sequentially delaying the ultrasonic wave transmission timing. At the same time, the ultrasonic probe 26 is also configured as described above, and at the same time, the ultrasonic beam B is formed by sequentially delaying the reception timing of the ultrasonic waves, similarly to the ultrasonic probe 16 in the above embodiment shown in FIG. Is configured to be converged and scanned and received. In this embodiment, the ultrasonic probes 22 and 26 that further transmit and receive the ultrasonic beam B are selectively operated. By selectively operating the ultrasonic probes 22 and 26, the incident angle of the center of the ultrasonic beam B with respect to the subject 4 is always 45 °. That is, the ultrasonic beam B transmitted by the plurality of ultrasonic probes 22.₁, B₂, B₃, B₄, B₅Is converged by sequentially delaying the transmission timing of the ultrasonic waves by the plurality of ultrasonic probes 22. At this time, each ultrasonic beam B₁To B₅Center line L₁, L₂, L₃, L₄, L₅Selects a group of ultrasonic probes 22 that operate to incident on the surface of subject 4 at an incident angle of 45 °. This group is uniquely determined by the depth of the subject 4 to be irradiated with the ultrasonic beam B, that is, by the path of the ultrasonic beam B. Therefore, by sequentially switching the ultrasonic probe 22 that sends out ultrasonic waves according to the path, the ultrasonic beam B in the depth direction of the subject 4₁To B₅It is possible to send an ultrasonic wave whose incident angle is always 45 ° with respect to this depth direction while moving. Therefore, if a defect 8 as shown in FIG. 2, for example, is present in the subject 4, the ultrasonic beam B is in the longitudinal direction of the defect 8.₁To B₅It is possible to constantly irradiate the defect 8 with an ultrasonic beam B having an incident angle of 45 ° while moving the defect 8. By the way, the ultrasonic beam B incident at 45 ° in this way is the most efficient. That is, the diffracted wave P at the upper and lower ends of the defect 8.₃, P₄The amplitude of is the largest.

【0021】

In the above embodiment, first, the approximate depth (upper and lower ends) of the defect 8 is obtained by the same method as that of the embodiment shown in FIG. 1, and then the ultrasonic beam incident on this depth portion at 45 °. If you select a group of ultrasonic probes 22 that drive to send B, the diffracted wave P generated at the upper and lower ends of defect 8.₃, P₄The amplitude of can be maximized.

【0022】

[Effect of the invention]

As described in detail with the above-described embodiment, in the invention described in [Claim 1], the ultrasonic wave transmitted from the transmitting side ultrasonic probe is received by the receiving side ultrasonic probe via the subject. In an ultrasonic flaw detector that detects defects inside the subject based on the waveform of the received ultrasonic wave, the transmitting side ultrasonic probe unit is an aggregate of ultrasonic probes in which a plurality of elements are arranged to form an array structure. By sequentially delaying the transmission timing of the ultrasonic waves output by each ultrasonic probe of the transmitting side ultrasonic probe, the ultrasonic beam transmitted from the transmitting side ultrasonic probe is converged. Since scanning is performed together with the ultrasonic beam, the amplitude of the diffracted wave at the upper and lower ends of the internal defect of the subject can be increased, and the ultrasonic beam can be oscillated over the entire depth direction of the subject. As a result, the depth of the defect detected based on the diffracted wave can be detected with higher accuracy.

【0023】

In the invention described in [claim 2], the ultrasonic waves transmitted from the transmitting side ultrasonic probe are received by the receiving side ultrasonic probe via the subject, and the ultrasonic waves are received based on the waveform of the received ultrasonic waves. In an ultrasonic flaw detector that detects defects inside a sample, the receiving side ultrasonic probe is composed of an aggregate of ultrasonic probes in which a plurality of elements are arranged to form an array structure, and the transmitting side ultrasonic probe is formed. By sequentially delaying the reception timing of ultrasonic waves by each ultrasonic probe of the unit, the ultrasonic beam transmitted and diffused by the transmitting side ultrasonic probe is effectively converged by each ultrasonic probe. Moreover, since the ultrasonic beam is scanned and received, the amplitude of the diffracted wave at the upper and lower ends of the internal defect of the subject can be increased, and the ultrasonic beam can be oscillated over the entire depth direction of the subject. it can. As a result, the depth of the defect detected based on the diffracted wave can be detected with higher accuracy.

【0024】

In the invention described in [claim 3], the ultrasonic waves transmitted from the transmitting side ultrasonic probe are received by the receiving side ultrasonic probe via the subject, and the ultrasonic waves are received based on the waveform of the received ultrasonic waves. In an ultrasonic flaw detector that detects defects inside a sample, the transmitting side ultrasonic probe is composed of an aggregate of ultrasonic probes in which a plurality of elements are arranged to form an array structure, and the transmitting side ultrasonic probe is formed. By sequentially delaying the transmission timing of the ultrasonic waves output by each ultrasonic probe of the unit, the ultrasonic beam transmitted from the ultrasonic probe on the transmitting side is converged and scanned, and the same array as that of the transmitting side. The receiving side ultrasonic probe is composed of a set of structured ultrasonic probes, and the timing of receiving ultrasonic waves by each ultrasonic probe of this ultrasonic probe is determined by the transmitting side ultrasonic probe. By synchronizing with the unit and sequentially delaying, the ultrasonic beam transmitted by the transmitting side ultrasonic probe is effectively converged and scanned by each ultrasonic probe, so that the subject can be received. The amplitude of the diffracted wave at the upper and lower ends of the internal defect can be increased, and the ultrasonic beam can be oscillated over the entire depth direction of the subject. Here, since the diffracted wave generated by the converged ultrasonic beam is received by effectively converging it, the amplitude of the diffracted wave is larger than that of the inventions described in the above [Claim 1] and [Claim 2]. Diffracted waves can be received. As a result, the depth of the defect detected based on the diffracted wave can be detected with the highest accuracy.

【0025】

The invention described in [claim 4] is one of the ultrasonic probes constituting the ultrasonic probe portion in any one of the ultrasonic flaw detectors described in [claim 1] to [claim 3]. The surface wave is transmitted and / or received, and the tip of the shoe of the ultrasonic probe is made of a material different from the surrounding members to transmit and / or receive the surface wave propagating on the surface of the subject. / Or because it is received, it is possible to obtain a good surface wave as a reference when specifying the depth of the defect. As a result, it is useful to satisfactorily identify the depth of the defect to be detected based on the diffracted wave.

【0026】

In the invention described in [Claim 5], the ultrasonic waves transmitted from the transmitting side ultrasonic probe are received by the receiving side ultrasonic probe via the subject, and the ultrasonic waves are received based on the waveform of the received ultrasonic waves. In the ultrasonic flaw detection method for detecting defects inside a sample, the transmitting side ultrasonic probe is composed of an aggregate of ultrasonic probes having an array structure in which a plurality of elements are arranged, and the transmitting side ultrasonic probe is formed. By sequentially delaying the transmission timing of the ultrasonic waves output by each ultrasonic probe of the unit, the ultrasonic beam transmitted from the transmitting side ultrasonic probe is converged, and the center of the ultrasonic beam with respect to the subject. Since the ultrasonic probe was selected so that the incident angle was always 45 ° and the ultrasonic beam was sent out, the ultrasonic beam incident at 45 ° was irradiated to each position in the depth direction of the subject. can do. Thus, the upper and lower ends of the defect can also be irradiated with an ultrasonic beam incident at 45 °, and a diffracted wave having the largest amplitude can be obtained. As a result, the depth of the defect detected based on the diffracted wave can be detected with high accuracy.

[Simple explanation of drawings]

[Figure 1]

It is explanatory drawing which conceptually shows the ultrasonic flaw detector which concerns on embodiment of this invention.

[Figure 2]

It is explanatory drawing which conceptually shows the ultrasonic flaw detection apparatus which concerns on other embodiment of this invention.

[Fig. 3]

It is explanatory drawing for demonstrating the TOFD method which concerns on the prior art.

[Fig. 4]

It is a waveform diagram which shows the relationship between the ultrasonic signal and the depth of a defect in the TOFD method shown in FIG.

[Explanation of symbols]

4 Subject 8 defects 11 Transmitter ultrasonic probe 12 Ultrasonic probe 13 shoe 13a tip 15 Receiving side ultrasonic probe 16 Ultrasonic probe 17 shoe 17a tip 21 Transmitter ultrasonic probe 22 Ultrasonic probe 25 Receiving side ultrasonic probe 26 Ultrasonic probe