JPH1164300A - Ultrasonic probe and ultrasonic flaw detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To check coupling stably with high reliability and check attenuation of a test material at the same time. SOLUTION: This apparatus comprises an ultrasonic probe main body 12, an ultrasonic flaw detector 21 which is connected to the ultrasonic probe main body 12, and makes instructions to transmit ultrasonic waves to the main body 12 and processing of waveforms received by the main body 12, etc., a coupling- checking acoustic mirror 13 set at a position where ultrasonic waves projected from the main body 12 are reflected at a front face of a pipe 16 to run forward, and an attenuation checking acoustic mirror 14 set at a position where the ultrasonic waves projected from the main body enter the pipe 16, are reflected at a rear face of the pipe 16 and further refracted at the front face of the pipe 16 to advance. A coupling material 17 is filled in the gap of the main body 12, the acoustic mirrors 13, 14 and the pipe 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe and an ultrasonic flaw detector for non-destructively inspecting defects in pipes, heat exchanger tubes and the like of various plants, and more particularly to an ultrasonic probe for performing a coupling check. The present invention relates to a probe and an ultrasonic flaw detector.

[0002]

2. Description of the Related Art In ultrasonic flaw detection, it is confirmed whether or not acoustic coupling between an ultrasonic probe and a test material is reliably performed, that is, whether or not ultrasonic waves are reliably incident on the test material. Therefore, it is necessary to check the coupling between the probe and the test material. As a conventional coupling check method, there are (1) a bottom echo method and (2) a surface reflection method as disclosed in JP-A-54-43087. These two methods will be described with reference to FIGS.

FIG. 8 is a cross-sectional view of an ultrasonic probe for performing a coupling check by a bottom echo method. An oblique probe 3 and a vertical probe 4 are provided in the ultrasonic probe block 1 with the acoustic division surface 2 interposed therebetween. The ultrasonic wave generated from the vertical probe 4 propagates in the test material 6 in a direction perpendicular to the surface thereof, is reflected by the rear surface of the test material 6, passes through the same beam path 7, and is detected by the vertical probe 4. Is done. A coupling check is performed by comparing the detected bottom surface echo level with a reference value, that is, a previously detected bottom surface echo level when the coupling is good.

FIG. 9 is a cross-sectional view of an ultrasonic probe for performing a coupling check by a surface reflection method. A reflector 8 is provided in the ultrasonic probe block 1 via an oblique probe 3 and a delay member / wedge 9 with the acoustic division surface 2 interposed therebetween. The reflecting plate 8 reflects the ultrasonic waves generated from the oblique probe 3 on the surface of the test material 6 and is mounted perpendicular to the traveling direction of the reflected ultrasonic waves.

The waveform received by the ultrasonic probe includes a surface echo, and when a defect exists within a distance of 1S in the test material 6, a defect echo appears in the target flaw detection range. By setting the time at which the surface echo reflected on the surface of the test material 6 is detected to be slightly later than the gate time range set as the target flaw detection range, the discrimination between the defect echo and the surface echo is facilitated and the direct coupling check is performed. Do.

[0006]

The following problems occur in the coupling check using the above-mentioned conventional ultrasonic probe.

In the case of the bottom surface echo method, since the oblique probe 3 is used for actual flaw detection and the vertical probe 4 is used for the coupling check, to be precise, the oblique probe 3 itself is used. It does not mean that a coupling check is being performed. In addition, the angle probe 3 and the vertical probe 4 and two probes are required, and the acoustic division surface 2 that partitions these two probes 3 and 4 is required.
The production of the ultrasonic probe block 1 is difficult and expensive. Furthermore, since the level of the ultrasonic wave transmitted through and reflected by the test material 6 is compared, there is a possibility that a coupling failure may occur even if there is a factor causing attenuation inside the test material 6.

On the other hand, in the case of the surface reflection method, the delay member 7 is required to set the detection position of the surface echo in the received waveform slightly after the target flaw detection range. Here, as the thickness of the test material 6 increases, the propagation distance of the ultrasonic wave propagating in the flaw detection range increases, and it is necessary to increase the thickness of the delay material 7 in order to increase the delay amount. Further, since the oblique probe 3 and the reflection plate 8 are incorporated in the wedge or the delay member 7, there is a difficulty in manufacturing the ultrasonic probe block 1.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an ultrasonic probe capable of performing a stable and highly reliable coupling check and at the same time an attenuation check of a test material. An object of the present invention is to provide a probe and an ultrasonic flaw detector.

[0010]

An ultrasonic probe according to a first aspect of the present invention includes an ultrasonic probe main body for transmitting and receiving ultrasonic waves, and an ultrasonic probe emitted from the ultrasonic probe main body. Of the sound waves, provided on the path of the ultrasonic wave reflected on the surface of the test material, a reflection plate for coupling check whose surface is arranged perpendicular to the path, and an ultrasonic wave emitted from the ultrasonic probe main body. Among the sound waves, the incident wave refracted into the test material is provided at a position where the incident wave is reflected on the back surface of the test material, further proceeds and refracted on the surface of the test material, and the surface is arranged perpendicular to the ultrasonic wave path. And a reflection plate for checking attenuation.

According to a second aspect of the present invention, in the ultrasonic probe according to the first aspect, the reflecting surfaces of the coupling check reflection plate and the attenuation check reflection plate are wedges. It is a structure that is not embedded in a material or a delay material.

The ultrasonic probe according to a third aspect of the present invention is the ultrasonic probe according to the first aspect, wherein the ultrasonic probe main body, the reflection plate for coupling check, and the reflection plate for attenuation check are provided. An ultrasonic probe comprising water filled between a plate and a plate. An ultrasonic flaw detector according to claim 4 of the present invention uses the ultrasonic probe according to claim 1 and the reflection plate for coupling check among the ultrasonic waves emitted from the ultrasonic probe. A coupling check electric circuit for performing a coupling check based on the reflected ultrasonic waves; and a meat of the test material based on the ultrasonic waves reflected by the coupling check reflector and the ultrasonic waves reflected by the attenuation check reflector. And a thickness measurement electric circuit for performing thickness measurement.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1A is a view showing the overall configuration of a small-diameter pipe insertion type ultrasonic flaw detector according to a first embodiment of the present invention, and FIG. It is the figure which showed the mode of ultrasonic wave propagation by a flaw detector in detail. The present ultrasonic flaw detector includes an ultrasonic probe 11 and an ultrasonic flaw detector 21.

The ultrasonic probe 11 is an ultrasonic probe main body 1
2, an acoustic mirror 13 serving as a coupling check reflector, and an acoustic mirror 14 serving as an attenuation check reflector
And the ultrasonic probe body 12 and the acoustic mirror 13,
A probe case 15 enclosing the probe case 14 is provided. A coupling material 17 is filled between the tube 16 as a test material and the probe case 15.

The coupling material 17 is generally called a couplant, which makes the ultrasonic probe 11 and the surface of the tube 16 adhere to each other to facilitate the propagation of ultrasonic waves to the tube 16.
Water, glycerin and the like are used.

The ultrasonic probe main body 12 transmits and receives ultrasonic waves, and is enclosed in a probe case 15. The ultrasonic wave emitting surface of the ultrasonic probe main body 12 is exposed from the probe case 15 into the coupling material 17, and the ultrasonic waves a are emitted toward the tube 16 as the test material. ing. The ultrasonic waves a emitted from the ultrasonic probe main body 12 are incident on the surface of the tube 16 at an incident angle ψ _{1 as} shown in FIG.
Incident. The incident angle ψ ₁ is such that the ultrasonic wave a propagates through the coupling material 17, refracts at the inner surface of the tube 16 at a refraction angle θ ₁ , and enters the tube 16. The angle is set so as to reach the outer surface of No. 16.

The acoustic mirror 13 is provided on the ultrasonic probe main body 12.
The ultrasonic waves a emitted from the tube 16 are provided at positions where the ultrasonic waves are reflected on the inner surface of the tube 16 and travel. That is, as shown in FIG. 1B, when the center point of the circular probe case 15 is O and the center axis of the tube 16 overlaps the point O, the ultrasonic probe main body 12 and the acoustic mirror 13 Are located symmetrically with respect to a straight line connecting the point where the ultrasonic wave a emitted from the ultrasonic probe main body 12 hits the inner surface of the tube 16 and the center point O.

The angle of the mirror surface of the acoustic mirror 13 is set perpendicular to the direction of incidence of the reflected wave c on the surface of the ultrasonic tube 16. Therefore, the acoustic mirror 13
Is reflected by the mirror 13 and can be received by the ultrasonic probe body 12 following the same path.

On the other hand, an ultrasonic wave a emitted from the ultrasonic probe main body 12 refracts and enters the tube 16, and the refracted wave b is reflected on the outer surface of the tube 16, and this reflected wave is further reflected on the inner surface of the tube 16. In the position where the light is refracted and travels through the coupling material 17,
An acoustic mirror 14 is provided. That is, as shown in FIG. 1B, the ultrasonic probe main body 12 and the acoustic mirror 14
Means that the ultrasonic waves emitted from the ultrasonic probe body 12
The position is symmetrical with respect to a straight line connecting a point O and a point which is refracted on the six surfaces and hits the outer surface of the tube 16.

The angle of the mirror surface of the acoustic mirror 14 is set to be perpendicular to the direction in which the ultrasonic wave d refracted from the tube 16 and incident on the coupling member 17 is incident. Therefore, the ultrasonic wave d incident on the acoustic mirror 14 is reflected on the surface of the mirror 14 and can be received by the ultrasonic probe main body 12 along the same path.

Further, an ultrasonic flaw detector 21 for controlling the transmission and reception of ultrasonic waves performed by the ultrasonic probe main body 12 is connected to the ultrasonic probe main body 12, and Processing such as a transmission command of a sound wave and a reception waveform received by the ultrasonic probe main body 12 is performed. Further, since the ultrasonic flaw detector 21 observes the received waveform, a display device for displaying the received waveform is built in.

The operation of the ultrasonic flaw detector according to the above embodiment will be described.

When an ultrasonic transmission command is issued from the ultrasonic flaw detector 21 connected to the ultrasonic probe main body 12, the ultrasonic probe main body 12 emits an ultrasonic wave a. The emitted ultrasonic wave a propagates through the coupling material 17 and the incident angle ψ ₁
At the inner surface of the tube 16. On the inner surface of the tube 16, part of the ultrasonic waves a enters the inside of the tube 16 at a refraction angle θ ₁ , and the remaining ultrasonic waves c are reflected at a reflection angle ψ ₂ and travel through the coupling material 17. The reflected ultrasonic wave c reaches the acoustic mirror 13, propagates along a path c → a opposite to the forward path a → c, and is received by the ultrasonic probe 11.

On the other hand, the ultrasonic wave b refracted and incident on the inside of the tube 16 propagates inside the tube 16 and is reflected on the outer surface of the tube 16. Then, the light propagates through the inside of the tube 16 and reaches the inner surface of the tube 16 again. Ultrasonic b reaching the inner surface of the tube 16 is refracted progress in the coupling member 17 at a refraction angle [psi _3, reaches the acoustic mirror 14.

The ultrasonic wave d arriving at the acoustic mirror 14 is reflected by the mirror surface, and the path d → b → a is reverse to the outward path a → b → d.
Are received by the ultrasonic probe main body 12. And
The received ultrasonic wave is converted into an electric signal, and each echo is displayed on the display device of the ultrasonic flaw detector 21 as shown in FIG. 2A and 2B, the horizontal axis represents time,
The vertical axis is the wave height. Here, the surface echo is caused by the ultrasonic wave that has traveled only along the path a, is reflected by the inner surface of the tube 16, and is received along the same path as the incident ultrasonic wave a.

Since the reflection point on the outer surface of the tube 16 is set on the intersection of the axis of symmetry of the transducer surface of the ultrasonic probe 11 and the mirror surface of the acoustic mirror 14, ψ ₁ = ψ It becomes ₃ . When a defect 18 exists inside the tube 16, the ultrasonic wave b is reflected by the defect 18 and a path b opposite to the outward path a → b
→ The signal is received by the ultrasonic probe main body 12 following a. The received ultrasonic waves are converted into electric signals, and the ultrasonic flaw detector 21
Is displayed by the display device. This defect echo is shown in FIG.
As shown in (b), the acoustic mirror 1 starts immediately after the surface echo.
Appears during the echo from # 3.

These various echoes are captured by the gate function of the ultrasonic flaw detector 21. That is, the ultrasonic flaw detector 21 is provided with three types of gates: a flaw detection gate, a coupling check gate, and an attenuation check gate.
Echoes 3 and 14 are taken in as analog signals.

The flaw detection gate is provided between the surface echo and the echo from the mirror 13, and flaw detection is performed depending on whether or not a defect echo appears in the flaw detection gate area. The coupling check gate is provided in accordance with the echo from the acoustic mirror 13. The attenuation check gate is provided in accordance with the echo from the acoustic mirror 14.

When a defect, a coupling failure or the like is detected by these gate functions, an alarm function of the ultrasonic flaw detector 21 gives a warning to the observer about the coupling failure or the defect detection. Signals indicating these defects, coupling failures, and the like are displayed and recorded by a pen recorder or the like as shown in FIG. Thus, by providing three types of gates, defect detection between the acoustic mirror 13 echoes from the surface echo, coupling check with the acoustic mirror 14 echo, and attenuation check with the acoustic mirror 14 echo can be performed simultaneously with the same ultrasonic wave. it can.

When the pipe 16 is made of steel, by using water as the coupling material 17 (couplant),
Approximately 3200m / s shear wave velocity in steel and 1500m underwater sound velocity
/ S, the same effect as when the delay member is provided can be obtained. That is, when a defect exists in the tube 16, the defect signal can be displayed before the coupling check signal and the attenuation check signal.

As described above, the ultrasonic waves a for flaw detection emitted from the ultrasonic probe main body 12 propagate through the coupling material 17, are reflected on the inner surface of the tube 16, are reflected on the acoustic mirror 13,
Ultrasound probe body 12 for both transmission and reception following the reverse path
Then, a direct type coupling check can be performed at the same time and with the same ultrasonic wave. Also, this ultrasonic wave is applied to the tube 16.
Since it does not propagate inside, it is not affected by a factor that causes attenuation inside the tube 16. The acoustic mirror 14 refracts the flaw detection ultrasonic waves a emitted from the ultrasonic probe main body 12 into the tube 16, reflects on the outer surface of the tube 16, and enters the coupling material 17. d is reflected and returned to the ultrasonic probe main body 12 in a reverse path, so that the
Can be checked.

Further, the coupling material 17 is filled between the acoustic mirrors 13 and 14 and the surface of the tube 16 and is not embedded in the wedge material or the delay material. Does not need to be considered, and the entire ultrasonic probe can be downsized.

(Second Embodiment) FIG. 5 is a diagram showing an overall configuration of an ultrasonic flaw detector according to a second embodiment of the present invention, and FIG. 6 is a diagram showing a reception waveform of the ultrasonic probe in the same embodiment. It is. The ultrasonic test equipment according to the present embodiment has substantially the same configuration as the ultrasonic test equipment according to the first embodiment.
The difference lies in that the thickness-measuring electric circuit section 22 is connected to the ultrasonic probe of the embodiment.

The propagation distance b of the ultrasonic wave b inside the tube 16 shown in FIG. 5 is equal to the acoustic mirror 1 as shown in the received waveform of FIG.
From the propagation distance 2 (a + 2b + d) of the echoes from the acoustic mirrors 13 and 14, the propagation distance 2 (a
+ C). Here, from a = c = d, the difference in propagation distance = 2 (a + 2b + d) −2 (a + c) = 4
b. Here, the distance between the echoes of the acoustic mirrors 13 and 14 shown in the waveform of FIG. 6 indicates the propagation time T, and between the propagation time T and the propagation distance 4b, T = 4b / (the sound velocity in the tube 16) ) Holds. Further, the refraction angle θ ₁ is determined by Snell's law, that is, sin θ ₁ / sinψ ₁ = (sound velocity in pipe) / (sound velocity in coupling material).

Further, in FIG. 5, the inner diameter of the tube 16 is R, and the angle formed by the tube axis between the inner surface of the tube 16 and the outer surface of the tube 16 of the ultrasonic wave a from the ultrasonic probe main body 12 is θ. Then, θ is known, and the following relational expression holds. Here, t is the thickness of the tube 16.

B / sin θ = R + t / sin (π−
θ ₁ ) = R / sin (θ ₁ −θ) Accordingly, the thickness t is obtained as t = b / sin θ {sin θ ₁ −sin (θ ₁ −θ)}.

As described above, the electric circuit section 22 for measuring the thickness shown in FIG. 5 detects the propagation time T from the attenuation check signal waveform received by the ultrasonic probe main body 12, and calculates the above relational expression from the propagation time T. The thickness t can be calculated more. Therefore, only by arranging the electric circuit unit 22 for thickness measurement in the ultrasonic flaw detector according to the first embodiment, not only the coupling check, flaw detection and attenuation check but also the flesh of the pipe 16 by the same ultrasonic wave at the same time. Thickness measurement becomes possible.

The clock section incorporated in the general ultrasonic thickness gauge is incorporated in the electric circuit section 22 for measuring the thickness, and the thickness t is calculated from the clock pulse count as shown in FIG. It is also possible to digitally display the determined thickness value t.

(Third Embodiment) FIG. 7 is a cross-sectional view showing a case where ultrasonic flaw detection is performed using an ultrasonic probe according to a third embodiment of the present invention. As shown in FIG. 7, the test piece 19 is immersed in a water tank or the like containing the coupling material 17 and is subjected to flaw detection by a water immersion method. Ultrasonic probe body 12 and acoustic mirror 1
The reference numerals 3 and 14 are rotatably mounted on rails or the like movable in three orthogonal axes, and move in the x, y, and z directions according to the shape of the test body 19.

The operation procedure is the same as that of the first embodiment,
In the ultrasonic probe according to the present embodiment, since the erection angle and the distance between the ultrasonic probe main body 12 and the acoustic mirrors 13 and 14 can be set to arbitrary values, the case where the shape of the test piece 19 is complicated. Even in the same manner as in the first embodiment, flaw detection, coupling check, and attenuation check can be simultaneously performed with the same ultrasonic wave.

The erection angle and the distance between the ultrasonic probe main body 12 and the acoustic mirrors 13 and 14 are set so that the mutual relationship shown in the first embodiment is similarly established.

[0043]

As described above, according to the ultrasonic probe and the ultrasonic flaw detector of the present invention, the ultrasonic wave emitted from the ultrasonic probe main body is reflected at the surface of the test material and advances to the position where the ultrasonic wave travels. The provided reflection plate for coupling check and the ultrasonic wave emitted from the ultrasonic probe main body are incident on the test material, and this incident wave is reflected on the back surface of the test material, and further proceeds on the surface of the test material. Since it is provided with an attenuating check reflector provided at a position where it is refracted and travels, (1) flaw detection is performed using only one ultrasonic probe,
A stable and reliable coupling check can be performed without being affected by the test material, and a test material can also be checked for attenuation. A minute defect can be detected by measuring the attenuation.

When the reflection surfaces of the coupling check reflection plate and the attenuation check reflection plate are not embedded in the wedge material or the delay material, the following effects are obtained in addition to the effect of the above (1). .

(2) There is no need to consider the occurrence of echoes in the wedge, and there is no need to consider the amount of delay, so that the probe as a whole can be downsized.

When the ultrasonic flaw detection is performed by filling the space between the ultrasonic probe main body and the reflection plate for coupling check and the reflection plate for attenuation check, the effects of the above (1) and (2) are obtained. In addition to the above, the following effects are obtained.

(3) Flaw detection, coupling check, and attenuation measurement can be performed with a single ultrasonic probe by a water immersion method even for a test material having a complicated shape.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the overall configuration of an ultrasonic flaw detector according to one embodiment of the present invention.

FIG. 2 is a view showing a reception waveform of the ultrasonic probe in the embodiment.

FIG. 3 is a diagram showing a reception waveform and various gates of the ultrasonic probe according to the embodiment.

FIG. 4 is an exemplary view showing a display example of a received waveform by a pen recorder in the embodiment.

FIG. 5 is a cross-sectional view illustrating an overall configuration of an ultrasonic inspection device according to a second embodiment of the present invention.

FIG. 6 is a view showing a reception waveform and signal processing of the ultrasonic probe according to the embodiment.

FIG. 7 is a cross-sectional view illustrating the entire configuration of an ultrasonic probe according to a third embodiment of the present invention.

FIG. 8 is a diagram showing an entire configuration of an ultrasonic probe that performs a coupling check by a conventional bottom echo method.

FIG. 9 is a diagram showing an entire configuration of an ultrasonic probe that performs a coupling check by a conventional surface reflection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Ultrasonic probe 12 Ultrasonic probe main body 13, 14 Acoustic mirror 15 Probe case 16 Tube 17 Coupling material 18 Defect 19 Test piece 21 Ultrasonic flaw detector 22 Electric circuit part for wall thickness measurement

Claims (4)

[Claims] An ultrasonic probe main body for transmitting and receiving ultrasonic waves, and an ultrasonic wave emitted from the ultrasonic probe main body is provided on a path of an ultrasonic wave reflected on a surface of a test material. A reflection plate for coupling check whose surface is arranged perpendicular to the course, and of the ultrasonic waves emitted from the ultrasonic probe body, incident waves refracted into the test material are reflected on the back surface of the test material. It is provided at a position where it further advances and refracts on the test material surface,
An ultrasonic probe characterized by comprising an attenuation check reflector whose surface is arranged perpendicular to the path of ultrasonic waves. 2. The ultrasonic probe according to claim 1, wherein
An ultrasonic probe, wherein the reflecting surfaces of the coupling check reflection plate and the attenuation check reflection plate are not embedded in a wedge material or a delay material. 3. The ultrasonic probe according to claim 1, wherein
An ultrasonic probe, wherein water is filled between an ultrasonic probe main body and a reflection plate for coupling check and a reflection plate for attenuation check. 4. An ultrasonic probe according to claim 1, wherein a coupling check is performed based on an ultrasonic wave reflected by a coupling check reflecting plate among ultrasonic waves emitted from the ultrasonic probe. An electrical circuit for performing a coupling check, and an electrical circuit for measuring the thickness of the test material based on the ultrasonic wave reflected by the reflection plate for coupling check and the ultrasonic wave reflected by the reflection plate for attenuation check. An ultrasonic flaw detector comprising: