JPS63256847A - Ultrasonic contactor - Google Patents

Abstract

PURPOSE:To prevent a noise echo from being generated in a material to be inspected by a vertical ultrasonic wave and to form a flaw detector with good S/N by providing an ultrasonic wave reflector at a specific position on the surface where the wedge of a probe contacts an acoustic coupler. CONSTITUTION:The reflector 9 made of a cork material is provided over the entire surface which is the surface behind the point where the sound pressure is maximum on the surface where the plastic wedge 3 of the ultrasonic probe 1 contacts the acoustic coupler 4 and <=-10dB in sound pressure from the point where the sound pressure is maximum. The main lobe 5 of the strong sound pressure is propagated to the surface of the material 7 to be inspected, but the side lobe 6 of small sound pressure reaches the reflector 9 and is reflected into the wedge 3. Consequently, the noise echo is prevented from being generated in the material to be inspected by the vertical ultrasonic wave and the probe with good S/N is obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides an ultrasonic probe for detecting defects, inclusions, etc. existing under the skin of bars, wires, etc. using ultrasonic angle flaw detection. It is related to.

[Conventional technology]

FIG. 2 is a diagram of a conventional ultrasonic probe device shown in, for example, Ultrasonic Flaw Detection Method (published by Nikkan Kogyo Shimbun in 1972).

2(8)(a) is a cross-sectional view of the ultrasonic probe, FIG. 2(b)
) is a flaw detection waveform chart using a conventional ultrasonic probe.

In the figure, (1) is an ultrasonic probe, (2) is a transducer that transmits and receives all ultrasonic waves, (3) is a plastic wedge, and (4) is water.

Acoustic coupling material made of oil etc. (5) is main rope with strong sound pressure strength, +61H main rope with weak sound pressure strength.

(7) is the material to be tested, α is the incident angle of the ultrasonic wave to the material to be tested (7), C is the center of the material to be tested (7), (8) is the flaw detection gate, and B is the main rope with weak sound pressure intensity. Bottom echo according to (6), gap between GVi ultrasonic probe (1) and test material (7).

T is the transmit pulse.

The conventional ultrasonic probe device is configured as described above, in order to perform flaw detection in the subepidermal area of the material to be inspected (7) while minimizing the unexplored area.

The angle angle flaw detection method is generally used. In the angle angle flaw detection method, when an ultrasonic wave is incident at a predetermined angle α to the normal line passing through the center c1 of the test material (7), a refraction angle corresponding to the incident angle α is given according to Snell's law. be.

The ultrasonic beam emitted from the transducer (2) has a main lobe (5) with a strong sound pressure intensity and a main lobe (6) with a weak sound pressure intensity.

In particular, when the material to be inspected (7) is a nine-piece material, the vibrator (2)
Main lobe (6) with weak sound pressure intensity generated from the end of
However, since the point of incidence on the material to be tested (7) is shifted from the center of the material to be tested (7), the angle of incidence of the ultrasonic wave becomes significantly smaller, especially behind the point of maximum sound pressure intensity, and the longitudinal wave ultrasound It can be seen that the signal propagates near the center C of the test material (7).

The above conditions become more pronounced as the outer dimensions of the test material (7) become smaller.

[Problem that the invention seeks to solve]

As shown above, when the main lobe (6) component with low sound pressure intensity is incident almost perpendicularly toward the center C of the test material (7), it propagates through the test material (7) as a longitudinal ultrasonic wave. It turns out. On the other hand, in an ultrasonic probe in which the incident angle α is set so that the main lobe (5) with strong sound pressure intensity propagates through the test material (7) as a transverse wave, The propagation time of the ultrasonic wave is set or calculated based on the transverse sound velocity of the test material (7), so the longitudinal ultrasonic wave due to the main lobe (6) component with weak sound pressure intensity becomes the bottom echo B and the sound Because the main lobe (51) with strong compressive strength is generated in a slightly shorter time than the time it takes for one pound of transverse ultrasonic waves to hit the side of the material to be inspected (7), it is always read into the flaw detection gate (8) as a noise component, and the S/ There was a problem of deteriorating the N ratio.

This invention was made to solve all of the above problems, and its purpose is to obtain an ultrasonic probe device with a good S/N ratio without allowing the main lobe, which has a weak sound pressure intensity, to enter the test material. do.

[Means for solving problems]

The ultrasonic probe according to the present invention has a sound pressure of 10 dB or less from the maximum point of the sound pressure intensity over the entire surface on the surface of the wedge in contact with the acoustic coupler, on the rear side of the point where the sound pressure intensity is maximum. , which is equipped with an ultrasonic reflector.

[For production]

In this invention, on the surface of the wedge in contact with the acoustic coupler, on the rear surface from the point where the sound pressure intensity is maximum, an ultrasonic reflector is provided over the entire surface of the sound pressure of 10 dB or less from the maximum point of the sound pressure intensity. , the main lobe of low sound pressure intensity generated from the end of the vibrator does not enter the specimen. Therefore, even in the flaw detection waveform diagram, it is possible to obtain an ultrasonic probe in which no noise component due to longitudinal ultrasonic waves is generated during the flaw detection gate.

〔Example〕

FIG. 1 is a diagram showing an ultrasonic probe showing an embodiment of the present invention.

FIG. 1(a) is a cross-sectional view of an ultrasonic probe, and FIG. 1(b) is a flaw detection waveform diagram by the ultrasonic probe of the present invention.

In the figure, fil Vi ultrasonic probe, (2) is the transducer, (3) is the wedge, (4) is the acoustic coupling material, (5) is the main lobe with strong sound pressure intensity, and f61H is the main lobe with weak sound pressure intensity. Lobe, (7) is the material to be tested, (8) is the flaw detection game 1-. (9
1 is a reflector made of cork material or the like according to the present invention, α is the angle of incidence of ultrasonic waves on the test material (7), C is the center of the test material (7), T is the transmission pulse, and G is the ultrasonic probe. This is the gap between the child (1) and the material to be tested (7).

In the ultrasonic probe configured as described above, the ultrasonic waves emitted from the transducer (2) have a main lobe (5) with a strong sound pressure intensity, and a main lobe (6) with a weak sound pressure intensity.
) is propagated through the wedge (3), and the main lobe (5) with high sound pressure intensity is propagated to the surface of the test material (7).

On the other hand, the main lobe (6) with low sound pressure intensity reaches the reflector (9) provided on the wedge (3) and is reflected into the detector (3).

In addition, the main lobe (5) with strong sound pressure intensity propagated to the surface of the test material (7) enters the test material (7) at a predetermined angle and can be determined simply by propagating as a transverse ultrasonic wave. Therefore, the material to be tested (
7) The longitudinal ultrasonic wave propagating toward the center 6C no longer exists. As a result, in the flaw detection waveform diagram, no noise echoes due to longitudinal ultrasonic waves are generated within the flaw detection gate (8) after the transmission pulse T.

The reason why the reflector (9) is provided in its entirety is the entire range of 10 dB or less from the maximum point of sound pressure intensity.

This is because a range of about -6 to -8 dB has the disadvantage that the intensity of transverse ultrasonic waves propagating through the test material (7) becomes weak. Also, in the range closer than -10dB, 9 reflectors (9)
Since this effect does not appear much, the entire sound pressure range is set to be lower than -10 dB in consideration of the balance between the two.

〔Effect of the invention〕

As explained above, the present invention is directed to an ultrasonic probe for a test material having a cylindrical external shape, in which ultrasonic waves are incident obliquely in the circumferential direction of the test material.

On the surface of the wedge in contact with the acoustic coupler, an ultrasonic reflector is provided on the rear surface of the point where the sound pressure intensity is maximum, covering the entire surface with a sound pressure of 10 dB or less from the point where the sound pressure intensity is maximum. By doing so, it is possible to prevent the main rope, which has a weak sound pressure strength, from entering perpendicularly toward the center of the test material.

As a result, no longitudinal ultrasonic waves are generated in the test phase, so no echoes that become noise components are generated within the flaw detection gate after the transmitted pulse, making it possible to supply an ultrasonic probe with a good S/N ratio. There is.

[Brief explanation of drawings]

Figure 1 (a) ij is a sectional view of the ultrasonic probe according to the present invention, Figure 1 (b) vi is a detection waveform diagram of the ultrasonic probe according to the present invention, and Figure 2 (a) is a cross-sectional view of the ultrasonic probe according to the present invention. The cross-sectional view of the sonic probe, FIG. 2(b), is a flaw detection waveform diagram by a conventional ultrasonic probe. In the figure, +11 is an ultrasound probe, (2) is an imager, (
3) is] the beginning (4) is the acoustic coupling material, (5) is the main rope with strong sound pressure strength, (6) is the side rope with low sound pressure strength, (7) is the test material, and (9) is the reflective material. It is the body. In addition, the same reference numerals (1 and - or equivalent parts are shown in each figure).

Claims (1)

[Claims] The outer shape of the test material is cylindrical, the ultrasonic wave is incident obliquely in the circumferential direction of the test material, and the gap between the test material and the ultrasonic probe is 2 to 3 mm or less. In ultrasonic probes used in
It has a wedge made of plastic such as acrylic resin, and on the surface of the wedge in contact with the acoustic coupler, the entire surface of the sound pressure is -10 dB or less from the point of maximum sound pressure intensity on the rear side from the point of maximum sound pressure intensity. An ultrasonic probe characterized by being equipped with an ultrasonic reflector.