JPH0412456Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultrasonic probe used for quantitative measurement of object defect height, size, etc. in ultrasonic angle flaw detection tests.

In recent years, various methods for quantitatively measuring the height of a defect in an object using ultrasound have been proposed, one of which is the edge peak echo method. This edge peak echo method uses one probe (e.g.
Ultrasonic flaw detection is performed using a single probe with a refraction angle (ultrasonic transmission direction angle) of approximately 45°.
Object 2 (overlay 4 on the surface of base material 3 in the figure)
For the defect Df, from the surface of
Ultrasonic beam is generated by scanning the probe 1 back and forth.
In this method, the defect height is estimated by transmitting and receiving UB, thereby capturing echoes from the upper and lower ends of the defect Df, and geometrically calculating their positions. Specifically, in Fig. 1, the defect Df is detected by scanning the probe 1 back and forth with respect to the defect Df.
An echo is captured from the lower end 5 of the beam, and the defect height d is calculated geometrically from the beam path w. The calculation formula is shown by the first formula from the geometrical relationship.

d=w cosθ (1) Such an edge peak echo method is currently the most accurate and practical. however,
In this edge peak echo method, the signal level is lower than that of the echo from the defective surface, and the range in which it appears is narrow, as shown by UB2 in Figure 2, so it is not always easy to confirm. Here, in Figure 2, the position of the probe 1 is taken as the horizontal axis, and the detected echo level is taken as the vertical axis. This figure shows how the echo level changes at the child position. In the figure, UB1 shows the change in peak echo level from the defect Df surface 6 in Figure 1, and UB2
is the output obtained from the lower end 5 of the defect Df.
Moreover, θ is the refraction angle of the probe used. As can be seen from the figure, the edge peak echo has a lower signal level than the echo from the defective surface, and its appearance range is narrower.

Therefore, for example, when applying the edge peak echo method to a pressure vessel such as a nuclear reactor vessel that has an austenitic stainless steel overlay installed, the overlay significantly attenuates the ultrasonic waves and noise occurs due to scattering. This makes it even more difficult to confirm edge peak echoes.

Figure 3 shows the edge peak echo (flaw detection angle, longitudinal wave) of an artificial defect opened on the surface of the overlay material.
45°), and the S/N (signal-to-noise ratio) is extremely poor when compared with the scanning graph of the echo from the defect surface (detection angle: 90° longitudinal wave) De shown in Figure 5, which will be described later. It can be seen that when performing flaw detection using only the flaw detection angle (longitudinal wave 45°), it is difficult to confirm the edge peak echo. In addition, the third
In Fig. 5, D _FP is the defect position of the object to be inspected,
OV indicates the overlapped part of the overlay, NZ indicates the noise, and PE indicates the peak echo.

This idea was created in view of the above circumstances.
A probe for measuring defects in a specimen using the edge peak echo method using ultrasonic waves includes a first probe having a predetermined refraction angle, and a probe located in front of the first probe in the scanning direction. a second probe arranged at a predetermined distance from the first probe and having a larger refraction angle than the first probe; The second probe, which is set larger than the probe, can detect echoes from defects at a farther position than the first probe, which has a smaller refraction angle, and can detect echoes from defects at a farther position than the first probe, which has a smaller refraction angle. By taking advantage of the fact that the defect is less susceptible to the influence of
It is an object of the present invention to provide an ultrasonic wave probe whose end peak echo can be easily identified and detected.

An embodiment of the present invention will be described below with reference to FIGS. 4 and 5.

FIG. 4 is a schematic diagram showing the configuration of this device, and 1
is the first probe. This probe 1 is, for example, a single probe with a refraction angle of 45°. Also, 2
1 is a second probe for detecting echoes from the defective Df surface of the object 2; A probe is used.

Both probes 1 and 21 are connected and held by a connecting member 22, with the ultrasonic transmission direction facing forward, and separated from each other by a distance l with probe 21 in front. Therefore, the probes 1 and 21 are moved integrally apart from each other at the predetermined interval.

In such a configuration, when the probes 1 and 21 are moved while transmitting and receiving ultrasonic waves, the refraction angle of the first probe 1 is 45°, so the refraction angle is 60° to 90°.
Since the second probe 21 can detect the echo from the defect Df at a farther position, the second probe 21 is first used to confirm the defect Df, and then the first probe 1 is used to confirm the defect Df. This allows the echo of the defective part to be detected. Furthermore, due to the refraction angle of the first probe 1, if the defect extends from the top to the inside, the first probe 1 will first detect the bottom end of the defect, so the probe 21 for detecting defect surface echoes will be used. Defect due to
After confirming Df, if an echo of the defect is detected by the first probe 1, check the defect
This means that the lower end of Df has been detected. this is,
Since this is done as the probes 1 and 21 move, the defect position and its lower end can be easily detected.

As explained in Figure 3, when a single probe is used for flaw detection, the peak echo at the edge of an artificial defect opened on the surface of an object such as an overlay material is noise from the overlapping part of the overlay, etc. Therefore, with a conventional single probe with a longitudinal wave of 45°, the S/N ratio was extremely poor as shown in the figure, making it difficult to confirm the end peak echo, but with this device, the second
For example, by using a single probe with a 90° longitudinal wave as the probe 21, the noise of the overlay material disappears as shown in Fig. 5, making it possible to clearly detect echoes from the defective part. become. In this way, by detecting the vicinity of the confirmed defect using the first probe 1 of the device of the present invention, the end peak echo can be easily identified.
can be detected.

Note that if the probe spacing is too far apart, the result will be the same as when one probe is used, and it will be difficult to identify the end peak echo, so the probe spacing should be 0 to 30 mm. It is desirable to do so.

As described in detail above, the present invention is a probe for measuring defects in an object using the edge peak echo method using ultrasonic waves.
a probe disposed at a predetermined distance from the first probe on the front side in the scanning direction of the first probe, and a refraction angle larger than that of the first probe. The second probe, which has a larger refraction angle than the first probe, detects defects at a position farther away than the first probe, which has a smaller refraction angle. The defect can be detected using the second probe first, and then the defect can be detected using the second probe. Since the echoes of the defect are detected using the probe, it is now possible to easily identify the peak echo at the edge of the defect, which allows inspection of defect height etc. to be performed with high accuracy. It is possible to provide an ultrasonic wave probe that can perform

It goes without saying that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with appropriate modifications within the scope of the invention without changing its gist.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the conventional device, Figure 2
The figure shows the relationship between the probe position and the detected echo height in a conventional device. Figure 3 shows the detected waveform of a defective surface echo in the conventional device. Figure 4 is a schematic diagram showing an embodiment of the present invention. FIG. 5 is a diagram showing a detection waveform of a defective surface echo by the defective surface echo detection probe in the apparatus of the present invention. 1... Probe for edge peak echo detection, 2...
...Object to be inspected, 21... Probe for detecting defective surface echoes.

Claims (1)

[Scope of utility model registration request] A probe for measuring defects in a specimen using the edge peak echo method using ultrasonic waves includes a first probe having a predetermined refraction angle, and a probe located in front of the first probe in the scanning direction. An ultrasonic probe comprising: a second probe arranged at a predetermined distance from the first probe and having a larger refraction angle than the first probe.