JPH04198859A - Ultrasonic probe and ultrasonic flaw detector - Google Patents

Abstract

PURPOSE:To lower the amplitude of the surface echo reflected from the surface of an object to be inspected by providing at least a pair of means converting received ultrasonic waves to electric signals mutually reverse in phase. CONSTITUTION:An ultrasonic probe 3 has piezoelectric vibrators 4a, 4b, 5a, 5b as electric signal conversion means. Two vibrators 4a, 4b and two vibrators 5a, 5b are connected by wiring so that the directions of electric polarization generated by strain become reverse. Therefore, the reflected waves respectively received by the vibrators are converted to electric signals mutually reverse in phase. The pulse signal from a transmitter is received only by the vibrators 4a, 4b and ultrasonic waves are transmitted to a material 7 to be inspected. These ultrasonic waves are reflected from the surface of the material 7 to be inspected and the reflected waves are received by the vibrators 4a - 5b to be transmitted to an adder 9. Two electric signals reverse in phase are added by the adder 9 and mutually negated to become almost zero. Therefore, the waveform of the reflected wave from the surface of the material to be inspected is almost not observed by the display of a receiver 10.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to ultrasonic flaw detection technology for detecting defects such as flaking and voids in a material to be inspected, and in particular to detecting defects near the surface of a material to be inspected. This invention relates to ultrasonic flaw detection technology suitable for

[Prior Art] A conventional technique for detecting defects in a material to be inspected using ultrasonic waves will be explained with reference to FIGS. 6A, 6B, and 6C.

FIG. 6A is an explanatory diagram when performing ultrasonic flaw detection using one ultrasonic probe, and the ultrasonic probe 20 is shown in a cross-sectional view.

The ultrasonic transducer 11 transmits and receives ultrasonic waves.

The ultrasonic transducer 11 is housed in a case 14 equipped with a connector 15 for exchanging signals with an external pulse transmitter/receiver, etc., and a back plate 13 for attenuating ultrasonic waves is provided on the back of the ultrasonic transducer 11. It is being

A pulse signal from an external transmitter (not shown) is converted into ultrasonic waves by the ultrasonic transducer 11, and the waves are transmitted to the test material 7 immersed in water in the water tank 18 via the front plate 12. do. The reflected waves from the surface or defects of the test material 7 are received by the same ultrasonic transducer 11 and converted into electrical signals, and the reflected waveform is observed with a CRT or the like of an external receiver (not shown). Defects inside the inspection material 7 are detected.

Next, the reflected waveform displayed on the CRT of the receiver will be explained using FIGS. 6B and 6C.

FIG. 6B schematically shows the reflected waveform of the ultrasonic wave when there is no defect in the test material 7, and FIG. 6C schematically shows the reflected waveform when there is a defect.

In FIGS. 6B and 6C, the horizontal axis shows time and the vertical axis shows amplitude.

T is the amplitude of the transmitted pulse, and S is the amplitude of the transmitted ultrasonic wave on the test material 7.
, B is the amplitude of the bottom echo reflected from the bottom surface of the test material 7, and F is the amplitude of the defect echo reflected from the defect in the test material 7.

On the CRT, the presence or absence of a defect can be detected based on the presence or absence of a defect echo F, and furthermore, the distance to the defect can be determined from the time between SF and the sound velocity in the material to be inspected.

[Problems to be Solved by the Invention] However, depending on the ultrasonic flaw detection device using the conventional ultrasonic probe described above, there is a problem that defects near the surface, particularly minute defects, cannot be detected accurately. .

The cause of this will be explained using FIGS. 6 and 7.

FIG. 7 shows the actual waveform of the ultrasonic waves generated when one pulse signal is applied to the ultrasonic transducer. The vertical axis shows amplitude and the horizontal axis shows time.

As shown in the figure, for one pulse signal, an ultrasonic wave having a plurality of waves is generated instead of an ultrasonic wave having one wave. For this reason, for example, as shown in FIG. 6A, when the test material 7 is a composite material consisting of a first member 16 and a second member 17, the first member 16 is made of stainless steel and its thickness is When it is thin (about several mm), the ultrasonic propagation time within the first member 16 is short, and the surface echo (S) and defect echo (F) appear close to each other, making it difficult to distinguish them from each other. The presence or absence of defects cannot be detected accurately, and flaw detection cannot be performed accurately.

Furthermore, when the first member 16 of the test material 7 immersed in water in the water tank 18 is made of steel, the acoustic impedances of the water and the steel material are significantly different from each other, so that the reflected waves of the ultrasonic waves from the interface between them are (Surface echo S) becomes extremely large. For this reason, when the surface echo S exceeds the maximum range of the amplifier used in the ultrasonic flaw detector, the amplifier saturates, causing abnormal operation immediately after a large signal, and further causing the problem of noise generation. be.

Moreover, when the surface echo (S) level fluctuates, defect echoes (F) generated in the vicinity thereof are affected, and defect detection cannot be performed correctly. Since the surface echo also has a shape as shown in FIG. 7, the surface echo and the defect echo overlap, making it impossible to easily detect minute defects.

Also, since the speed of sound in water is approximately 174 times that in steel, if there is a recess on the surface of the test material 7, which is a steel material, the surface echo (S
) on the time axis on the CRT in the receiver approaches the waveform of the defect echo (F) when there is no recess, making it difficult to distinguish between the two, and S
There is a problem that /N decreases.

Furthermore, in order to detect defects near the surface, increasing the frequency of the transmitted ultrasonic waves increases the amount of attenuation, resulting in a problem of decreased sensitivity.

A first object of the present invention is to provide an ultrasonic probe that reduces the amplitude of surface echoes (S) reflected from the surface of a test material.

A second object of the present invention is to improve the S/N ratio in detecting defects such as peeling and voids near the surface of a test material by using the above-mentioned ultrasonic probe, and to provide ultrasonic flaw detection that can easily identify minute defects. The goal is to provide technology.

[Means for Solving the Problems] The first object is to provide an ultrasonic probe comprising at least one pair of electro-acoustic converting means for converting received ultrasonic waves into electrical signals having mutually opposite phases. It can be achieved.

The second object is achieved by using an ultrasonic flaw detection apparatus comprising the ultrasonic probe and an adding means for adding electrical signals from the ultrasonic probe and outputting the result. It can be achieved.

A piezoelectric vibrator, a magnetostrictive vibrator, or the like is used as the electroacoustic transducer.

[Function] Next, the function of the present invention will be described in the case of an ultrasonic flaw detection device equipped with an ultrasonic probe having a pair of electroacoustic converting means that convert received ultrasonic waves into electrical signals having mutually opposite phases. will be explained as an example.

In order to detect defects in the test material, the ultrasonic probe is moved relative to the test material.

At this time, a signal pulse for ultrasonic wave transmission is transmitted to only one of the two electroacoustic transducers.

The electroacoustic transducer that receives this signal pulse transmits ultrasonic waves toward the material to be inspected.

The transmitted ultrasonic waves are first reflected by the surface of the material being tested,
The reflected waves are received by two electroacoustic transducers.

The received reflected waves from the surface are converted into electrical signals in each electroacoustic conversion means.

However, since the two electroacoustic conversion means convert the reflected waves received by each into electrical signals with opposite phases,
By adding the two electrical signals, they cancel each other out and become zero. That is, by using two electro-acoustic converting means that convert into electrical signals having mutually opposite phases, the waveform of the reflected wave from the surface is hardly observed on a display device such as a receiver.

The same applies to the reflected waves from the bottom surface of the test material.

When both electroacoustic transducers are located on a defect during flaw detection of a material to be inspected, reflected waves from the defect are rarely observed for the same reason as above.

Next, consider a case where only one electroacoustic transducer comes over a defect during flaw detection.

In this case, the reflected wave from the surface is
is rarely observed. However, the reflected waves from defects are
Since only one of the electroacoustic transducers receives the wave, even if the electrical signals from the two electroacoustic transducers are added, they are not canceled and can be observed as a reflected waveform on the display device.

In other words, even if a defect exists near the surface but the amplitude of the reflected wave from the surface is large, the presence or absence of the defect cannot be clearly detected using conventional techniques, the present invention can detect the defect. For example, since the reflected waveform from the surface can be almost completely canceled out on the display device, it is possible to reliably detect the presence or absence of defects near the surface.

[Example] A first embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows a water tank 1 using the ultrasonic flaw detection device of this embodiment.
FIG. 8 is an explanatory diagram of the situation when ultrasonic flaw detection is performed on the test material 7 in the test piece 8 when viewed from above.

Figure 2 shows a water tank 1 using the ultrasonic flaw detection device of this embodiment.
FIG. 8 is an explanatory diagram of the situation when ultrasonic flaw detection is performed on the test material 7 in the test piece 8 when viewed from the side.

A broken line 8 indicates a defect in the material 7 to be inspected.

First, the configuration of the ultrasonic flaw detection apparatus of this embodiment will be explained using FIGS. 1 and 2.

As shown in the figure, this ultrasonic flaw detection device includes transmitting means such as a transmitter 1 that transmits a pulse signal for transmitting ultrasonic waves, and an ultrasonic test device that transmits ultrasonic waves according to the pulse signals from the transmitter 1. Piezoelectric vibrators 4a and 4b transmit waves to the material 7, receive reflected waves from the material 7, convert them into electrical signals, and output them.
, 5a, 5b, an adding means such as an adder 9 that adds and outputs the received signals from the ultrasound probe 3, and a pulse signal output from the transmitter 1. It is configured to include signal switching means such as a signal switching device 2 that prevents input from being input to the adder 9.

Further, the ultrasonic probe 3 includes 4 as an electroacoustic transducer.
comprising four piezoelectric vibrators 4a, 4b, 5a, 5b,
Among these four piezoelectric vibrators, two piezoelectric vibrators 4a,
4b and the other two piezoelectric vibrators 5a and 5b are wired so that the directions of electric polarization caused by strain are opposite to each other. 4a in Figure 1 that this polarization direction is opposite.
, 4b.

In 5a and 5b, it is represented by the symbol 10 and -.

Furthermore, these four piezoelectric vibrators are arranged at approximately equal intervals, with 4a and 4b placed in the center, and 5a and 5b placed at both ends.

Further, the pulse signal from the transmitter 1 is transmitted to the piezoelectric vibrator 4a,
4b only.

Furthermore, the reflected wave from the test material 7 is transmitted to the four piezoelectric vibrators 4a.
, 4b, 5a, and 5b, and transmitted to the adder 9 as an electrical signal.

Note that in the above example, it is assumed that one ultrasound probe is equipped with four piezoelectric transducers, but it is assumed that one ultrasound probe is equipped with four piezoelectric transducers. It's okay.

Further, the adder 9 may be simply connected to an electric wire.

Next, the case of ultrasonic flaw detection of a test material using the above-mentioned ultrasonic flaw detection apparatus will be explained with reference to FIGS. 1 to 3.

FIG. 3 shows an ultrasonic waveform, with the horizontal axis representing time and the vertical axis representing amplitude.

In the same figure, ■ indicates the signal of the reflected wave from the surface of the test material (surface echo S) received by the piezoelectric vibrators 4a and 4b, and the signal of the reflected wave from the defect in the test material (defect echo S). F).

(3) is the signal of the reflected wave from the surface of the test material (surface echo S) received by the piezoelectric vibrators 5a and 5b, and the signal of the reflected wave from the defect in the test material (defect echo F). represent. ■ is,
It represents the waveform of the sum of the above-mentioned (■) and (2) added by the adder 9.

When actually performing ultrasonic flaw detection on a test material, the test material and the ultrasonic flaw detector are moved relative to each other. Suppose it is stopped.

Moreover, as shown in FIG. 1.2, the defect 8 in the test material 7 transmits the reflected wave from the defect 8 to the three piezoelectric sensors 4a and 4.
It is assumed that the signals b and 5b exist at the position where the waves are received.

A process in which a pulse signal from the transmitter 1 is converted into an ultrasonic wave, reflected in a material to be inspected, and is represented as a reflected waveform at the receiver 1o will be described.

The pulse signal transmitted from the transmitter 1 passes through the signal switch 2 and is input only to the piezoelectric vibrators 4a and 4b, where it is converted into an ultrasonic wave, and the ultrasonic pulse is transmitted into the water via the front plate 6. Ru.

Surface echo reflected from the surface of the test material 7 (S, arrow 21
) and the defect echo reflected from the defect 8 in the test material 7 (
F) means piezoelectric vibrators 4a and 4b with a time difference corresponding to the distance between the surface and the defect.

The signal is received at 5b, converted into an electrical signal, and transmitted to the adder 9 via the signal switch 2.

In addition, the piezoelectric vibrator 5a receives a surface echo (
S) is received, converted into an electrical signal, and transmitted to the adder 9.

In the adder 9, these signals are added each time,
The result is sent to receiver 1o.

FIG. 3 shows the reflected waveforms received by each piezoelectric vibrator as described above, and the waveform obtained by adding them together.

A signal representing the waveform of the ultrasonic wave reflected on the surface of the test material 7 will be explained.

The reflected waveform signal from the surface of the test material that is received by the piezoelectric vibrators 4a and 4b has the waveform shown by the circle in FIG. The reflected waveform signal has a waveform with the same absolute value of amplitude and opposite phase compared to the signal (■) in FIG. 3, as shown in (■).

This happens with the piezoelectric vibrators 4a and 4b.

This is because the polarization directions of the piezoelectric elements 5a and 5b are opposite to each other, so that the phases of the respective received signals differ by 180°. As a result, when the two reflected waveforms are added together in the adder 9, the two reflected waves cancel each other out,
Its value becomes almost zero.

Such a state is shown as surface echo S in FIG.

Next, the waveform of the ultrasonic wave reflected by the defect 8 in the test material 7 will be explained.

The reflected wave from this defect 8 is transmitted to the piezoelectric vibrator 4a.

The waves are received by 4b and 5b. The piezoelectric vibrator 5a does not receive the wave.

The results are shown in ■■ in Figure 3. As mentioned above, the directions of F in FIG. 3 and F in FIG.

This is because the polarization directions of the piezoelectric elements 5a and 5b are opposite to each other, so that the phases of the respective received signals differ by 180°.

Also, regarding the absolute value of the amplitude of F, ■ in Figure 3 is approximately 2
The reason why the reflected wave from the defect 8 is doubled is that the reflected wave from the piezoelectric vibrator 5a
This is because in some cases the waves are not received. As a result, when the above two reflected waveforms are added in the adder 9, the two reflected waves become as shown in Figure 3 (■), and the ratio of the reflected waves from the surface, which is added in the same way, is existence becomes clear.

In Fig. 3, the surface echo and the defect echo are shown separated in time for the sake of explanation, but when a defect exists near the surface, the two echoes are not separated in time and cannot be distinguished. Have difficulty.

Therefore, when a test material is tested using the above-mentioned ultrasonic flaw detection device, defects near the surface can be clearly detected.

Note that when the piezoelectric vibrators are arranged in an arbitrary polarization direction, respective vector addition outputs are obtained from the adder 9, and the amplitude of the surface echo (S) decreases in the same manner as above.

Next, when detecting a defect in a material to be inspected using the ultrasonic flaw detection device of this embodiment described above, two piezoelectric vibrators receive the reflected wave from the defect in the material to be inspected. An example of detecting a defect when the defect exists in a wave position will be explained with reference to FIGS. 4A-E.

This example is an example where the ultrasonic probe and the specimen are moving relatively.

In FIGS. 4A to 4E, description will be made assuming that the specimen 7 is moving from the right side to the left side.

In each case, (a) shows the arrangement and polarization direction of the piezoelectric vibrators. (b) shows how the material to be inspected moves and, as a result, the position of the defect changes. (c) shows the output signal of the adder 9, S represents a surface echo, and F represents a defect echo.

FIG. 4A shows that the position of the defect 8 in the material 7 to be inspected is
The case is shown in which only the piezoelectric vibrator 5b is located at a position where it receives reflected waves from the piezoelectric vibrator 5b.

In this case, the amplitude of the surface echo (S) decreases because it is the addition of signals with different phases from the piezoelectric vibrators 4a, 4b and 5a, 5b, but on the other hand, the amplitude of the surface echo (S) decreases.
The amplitude of F) does not decrease because it is only the signal from the piezoelectric vibrator 5b.

FIG. 4B shows that the position of the defect 8 in the material 7 to be inspected is
The case is shown in which the piezoelectric vibrators 4b and 5b are located at positions where they receive reflected waves from.

In this case, the surface echo (S) and the defect echo (
Since the amplitudes of F) and F) are the addition of signals having different phases, both of them decrease.

FIG. 4C shows that the position of the defect M8 in the test material 7 is
The case is shown in which piezoelectric vibrators 4a and 4b are located at positions where they receive reflected waves from.

In this case, the amplitude of the surface echo (S) decreases because it is an addition of signals with different phases, but -4, the amplitude of the defect echo (F) is the sum of the signals from the piezoelectric vibrators 4a and 4b. Although the phase is opposite to that in FIG. 4A, the amplitude of the signal does not decrease.

The case of FIG. 4D is the same as the case of FIG. 4B, and the same amplitude of the 8-force signal as in FIG. 4A is obtained in the case of FIG. 4E.

As mentioned above, the surface echo (
The amplitude of S) is always kept low, but the defect echo (F) can be detected depending on the position of the defect 8 without reducing the amplitude of the received signal, so with a good S/N, Defect echoes (F) can be detected.

Next, when detecting a defect in a material to be inspected using the ultrasonic flaw detection device of this embodiment described above, the size of the defect in the material to be inspected is determined by the reflection from the defect by the four piezoelectric vibrators. An example of defect detection when the size is large enough to receive waves is shown in Section 5A.
- This will be explained using diagram F.

This example is an example in which the ultrasonic probe and the specimen are moving relative to each other, as in the above example.

In FIGS. 5A to 5F, description will be made assuming that the specimen 7 is moving from the right side to the left side.

In each figure, (a) shows the arrangement and polarization direction of the piezoelectric vibrators. (b) shows how the material to be inspected moves, and as a result, the position of the defect 8 changes. (c) shows the output signal of the adder 9.

S represents a surface echo and F represents a defect echo.

FIG. 5A shows that the position of the defect 8 in the specimen 7 is
The case is shown in which only the piezoelectric vibrator 5b is located at a position where it can receive reflected waves from.

In this case, the amplitude of the surface echo (S) decreases because it is the addition of signals with different phases from the piezoelectric vibrators 4a, 4b and 5a, 5b, but on the other hand, the amplitude of the surface echo (S) decreases.
The amplitude of F) does not decrease because it is only the received signal from the piezoelectric vibrator 5b.

As a result, the output signal of the adder as shown in the lower row is obtained, and the existence of the defect 8 becomes clear.

FIG. 5B shows that the position of the defect 8 in the material 7 to be inspected is
The case is shown in which the piezoelectric vibrators 4b and 5b are located at positions where they receive reflected waves from.

In this case, the surface echo (S) and the defect echo (
Since the amplitudes of F) and F) are the addition of signals having different phases, both of them decrease.

FIG. 5C shows that the position of the defect 8 in the material 7 to be inspected is
The reflected waves from the piezoelectric vibrators 4a and 4b.

5b is located at the position where the waves are received.

In this case, the amplitude of the surface echo (S) decreases because it is an addition of signals with different phases.

On the other hand, the amplitude of the defect echo (F) is
The signal from either piezoelectric vibrator 4a or 4b and the signal from 5b cancel each other out, but the signal from either 4a or 4b is sent to the receiver as an output waveform. appear.

As a result, the output signal of the adder as shown in the lower row is obtained, and the existence of the defect 8 becomes clear.

In the case of Figure 5D, one surface echo (S) and a defect echo (F
) are canceled together.

In the case of FIG. 5E, the same amplitude of the output signal is obtained as in the case of FIG. 5C.

Moreover, in the case of FIG. 5F, the same amplitude of the output signal as in the case of FIG. 5A is obtained.

As mentioned above, by using the ultrasonic flaw detection device of this embodiment, even if the size of the defect 8 in the test material 7 changes,
The amplitude of the surface echo (S) output from the adder 9 is always kept low, while the defect echo (F) can be detected in certain cases, making it easy to identify the defect echo (F) and Defects such as delamination and voids can be detected in the test material 7 such as or dissimilar metal welding materials.

Furthermore, when detecting only small-sized defects 8 in the test material 7, a pair of piezoelectric vibrators with mutually different polarization directions may be used.

When the defect 8 is large, it can be easily dealt with by changing the spacing between the piezoelectric vibrators.

In this example, flaw detection of a test material under water was explained as an example, but the ultrasonic flaw detection device of this embodiment can be used not only for flaw detection of a test material under water, but also for flaw detection methods using wedges, etc. Can be used for various flaw detection methods.

(Hereinafter referred to as margins) Next, a second embodiment of the present invention will be described using FIG.

FIG. 8 is an explanatory diagram, viewed from the side, of how a test material is subjected to ultrasonic flaw detection using the ultrasonic flaw detection apparatus of the second embodiment.

As shown in the figure, the ultrasonic flaw detection device of this embodiment has piezoelectric vibrators 80a, 80b, 82a, 82b having mutually opposite phases.
is arranged.

The two central piezoelectric vibrators 80a and 80b are equipped with a transmitter 1.
Give the excitation signal directly from the On the other hand, the signal from the transmitter is applied to the phase inverter 81 to provide excitation signals with opposite phases to the piezoelectric vibrators 82a and 82b at both ends.

As a result, the ultrasonic waves transmitted from both piezoelectric vibrators become waves with the same phase. The reason for this configuration is that when waves with opposite phases are transmitted, the power may decrease due to cancellation of the waves.

Next, the reception will be explained.

The ultrasonic waves reflected from the surface of the test material 7 are transmitted through a piezoelectric vibrator 80a,
80b, 82a, and 82b. Due to this ultrasonic wave, the signals output from the two piezoelectric vibrators 80a and 80b in the center and the signals output from the piezoelectric vibrators 82a and 82b at both ends are opposite in polarity to each other. The result is a signal with an opposite phase. When these two signals are added by the adder 9, due to the cancellation of the opposite phase signals,
The addition output becomes zero.

According to the ultrasonic flaw detection apparatus of this embodiment, during transmission, the piezoelectric vibrators having mutually opposite phases are excited with signals having mutually opposite phases, so that the transmission power is doubled. As a result, the power of the received signal also doubles, making it possible to increase the S/N ratio and making it possible to apply this method to test materials with large attenuation.

In addition, when transmitting only with the piezoelectric vibrators 80a and 80b in the center, the reflected signal from the test material is strongly incident on the piezoelectric vibrators 80a and 80b in the center, and the piezoelectric vibrators 80a and 80b at both ends
The signals incident on a and 82b are transmitted to the central piezoelectric vibrator 80a.
, 80b, the signal levels output from the positive-phase and negative-phase piezoelectric vibrators 80a, 80b, 82a, and 82b become unbalanced, and a sufficient cancellation effect cannot be expected.

On the other hand, according to the ultrasonic flaw detection apparatus of this embodiment, since ultrasonic waves are emitted from all the piezoelectric vibrators, the output from each of the positive phase and negative phase piezoelectric vibrators 00a, 80b, 82a, and 82b is The signal is balanced and a sufficient cancellation effect can be expected.

[Effects of the Invention] As explained above, the present invention includes a pair of electroacoustic transducers that convert received ultrasonic waves into electrical signals having mutually opposite phases, and an addition method that adds the received signals from each electroacoustic transducer. Due to the structure in which the detector is provided, the amplitude of the surface echo reflected from the surface of the material to be inspected is always reduced, while the amplitude of the defect echo reflected from the defect can be detected as a signal that is not canceled out, so the S/N of the defect echo can be reduced. It will improve.

As a result, it has become possible to easily perform high-performance inspections for detecting defects such as delamination and voids on materials to be inspected, such as clad materials and dissimilar metal welding materials, and is particularly effective in detecting defects near the surface. be.

[Brief explanation of the drawing]

Fig. 1 is an explanatory view from above showing the state of ultrasonic flaw detection of a test material using the ultrasonic flaw detection device of the first embodiment, and Fig. 2 shows the situation when the ultrasonic flaw detection device of the first embodiment is used An explanatory diagram showing the situation when ultrasonic flaw detection is performed on a test material when viewed from the side, Fig. 3 is an illustration of the ultrasonic waveform, Fig. 4 is an explanatory diagram showing an example of defect detection, and Fig. 5 is an example of defect detection. FIG. 6 is an explanatory diagram showing the prior art, FIG. 7 is an explanatory diagram showing the actual waveform of the ultrasonic wave generated when one pulse signal is applied to a piezoelectric vibrator, and FIG. FIG. 6 is an explanatory side view of a state in which a test material is subjected to ultrasonic flaw detection using the ultrasonic flaw detection apparatus of the second embodiment. 1... Transmitter, 2... Signal switch, 3... Ultrasonic probe, 4a, 4b, 5a, 5b, 80a, 8
0b. 82a, 82b...Piezoelectric vibrator, 7...Test material, 8
...Defect, 9...Adder, 10...Receiver, 81...
Phase inverter. Figure 1 6, Front plate 9: Adder Figure 2 Figure 3 Figure 4A Figure 148 Figure 4C Figure 4D Figure 5A Figure 5B Figure 5C Figure 5D rv)

Claims (1)

[Scope of Claims] 1. In an ultrasonic probe equipped with electroacoustic conversion means for transmitting and receiving ultrasonic waves, the electroacoustic conversion means converts received ultrasonic waves into electrical signals having mutually opposite phases. An ultrasonic probe comprising at least one pair of. 2. The ultrasonic probe according to claim 1, wherein the electroacoustic converting means are arranged on the same plane. 3. An ultrasonic probe equipped with a piezoelectric vibrator that transmits and receives ultrasonic waves, characterized in that it is configured with at least one pair of piezoelectric vibrators with mutually different polarization directions. Child. 4. The ultrasonic probe according to claim 3, wherein the piezoelectric vibrators are arranged on the same plane. 5. In an ultrasonic flaw detection device that transmits and receives ultrasonic waves to detect defects in a test material, the ultrasonic probe according to claim 1, 2, 3, or 4, and this ultrasonic probe. 1. An ultrasonic flaw detection device comprising: an adding means for adding electrical signals from the probes and outputting the result. 6. A transmitting means for transmitting a pulse signal for transmitting ultrasonic waves, and transmitting ultrasonic waves to a specimen material according to the pulse signal from the transmitting means, and transmitting ultrasonic waves reflected from a reflective surface in the specimen material. At least one pair of piezoelectric vibrators is provided, one for receiving sound waves and the other for receiving only the ultrasonic waves reflected from the reflective surface in the test material, and the phase of each piezoelectric vibrator when receiving waves is an ultrasonic probe having an opposite phase; an adding means for adding the received signals from the piezoelectric vibrator and outputting the result; and a pulse signal output from the transmitting means being input to the adding means. An ultrasonic flaw detection device comprising: signal switching means for preventing 7. Sending ultrasonic waves to the material to be inspected, receiving the ultrasonic waves reflected by the reflective surfaces in the material, and detecting the reflected waves from defects, determines the presence or absence of defects in the material to be inspected. In the ultrasonic flaw detection method for examining Ultrasonic waves are transmitted into the material, the reflected waves from the reflective surface of the material to be tested are converted into electrical signals by both electroacoustic conversion means, and the electrical signals are added together to generate the reflected waves from the surface of the material to be tested. An ultrasonic flaw detection method characterized by detecting defects in a material to be inspected by observing electrical signals from defects in the material to be inspected while canceling electrical signals from the defect in the material to be inspected. 8. A transmitting means for transmitting a pulse signal for transmitting ultrasonic waves, a phase inverting means for inverting the phase of this pulse signal, and transmitting ultrasonic waves to a specimen in accordance with the pulse signal via the phase inverting means. A piezoelectric vibrator receives the ultrasonic wave that waves and is reflected from a reflective surface in the material to be tested, and transmits the ultrasonic wave to the material to be tested in accordance with a pulse signal that does not go through the phase inverting means. a piezoelectric vibrator that receives ultrasonic waves reflected from a reflecting surface of the ultrasonic transducer; addition means for adding the received signals from and outputting the result; and signal switching means for preventing the pulse signal output from the transmission means from being input to the addition means. Features of ultrasonic flaw detection equipment. 9. When transmitting ultrasonic waves to the material to be tested and receiving the waves reflected from the surface of the material to be tested, the ultrasound waves reflected from the surface of the material to be tested are converted into electrical signals with mutually opposite phases. Ultrasonic waves are transmitted from one electroacoustic transducer of a pair of electroacoustic transducers to the specimen material, and reflected waves from the surface of the specimen material are converted into electrical signals by both electroacoustic transducers. , a surface reflected wave suppression method characterized by adding these electrical signals and canceling the electrical signals of the reflected waves from the surface of the material to be inspected.