JP2001083123A - Local immersion type ultrasonic probe and ultrasonic inspection device equipped with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a local immersion type ultrasonic probe which is more reduced in size and can execute high-accuracy ultrasonic inspections and an ultrasonic inspection device which is small sized and with high versatility and can evaluate the soundness of the surface layer of an object to be inspected with high accuracy to the end section of the object regardless of the thickness and kind of the base material, state of the bottom face, etc. SOLUTION: An ultrasonic probe 1 is constituted in such a way that a through hole 3C is made from the upper surface of a vibrator 2 to the surface surface of an acoustic lens 3 at the central parts of the vibrator 2 and lens 3 and an ultrasonic medium supplying pipe 4 is set up in the hole 3C. An ultrasonic inspection device is constituted of an ultrasonic scanning section equipped with a local immersion type ultrasonic probe 1, the driving section of the scanning section, and an arithmetic processing section which controls the scanning section through the driving section and executes inspections on a coating film formed on the surface of a base material which is an object to be inspected for defects.

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 inspection apparatus provided with the same, and more particularly, to a configuration of an ultrasonic medium supply path in a local immersion type ultrasonic probe and the local immersion ultrasonic probe. The present invention relates to a configuration of an ultrasonic inspection apparatus that evaluates the soundness of a surface of a subject using an ultrasonic probe of a type.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open Publication No.
As described in, for example, Japanese Patent Application Laid-Open No. 5 (1993) -2005, there is known a technique for non-destructively evaluating the adhesion of a thermal spray coating formed on the surface of a metal material using ultrasonic waves.

[0003] In general, in order to evaluate the adhesion of the interface between two materials, a focusing type ultrasonic probe is arranged to face a subject, and the focal point of ultrasonic waves transmitted from the ultrasonic probe is set to two. A method is adopted that matches the interface between two materials and detects the echo intensity from the interface. However, when the test object is a thermal spray coating formed on the surface of the base material, since the thermal spray coating is a thin film of about 0.1 to 0.3 mm, ultrasonic waves are transmitted from the thermal spray coating to the test subject. In this case, it is practically impossible to separate the echo from the surface of the thermal spray coating from the echo from the interface, and it is impossible to evaluate the adhesion of the thermal spray coating to the base material. For example, considering a WC-based thermal spray coating having a thickness of 0.1 mm formed on the surface of the base material, the thermal spray coating has a large high-frequency attenuation, and the surface has irregularities of several μm to several tens μm. Is an ultrasonic wave of 5 to 20 MHz (200
５０50 ns), the longitudinal wave velocity of the sprayed coating is about 4200 m / s, and the time difference between the echo from the coating surface and the echo from the interface is 47.6 ns.
Since it is only s, it can be seen that both echoes cannot be separated.

Therefore, in the thermal spray coating evaluation method described in the above-mentioned known example, as shown in FIG. 9, a test object 100 having a thermal spray coating 102 formed on the surface of a base material 101 and a focused ultrasonic probe 200 Are arranged facing each other in water (the symbol W in the figure indicates water as an ultrasonic medium), and the ultrasonic probe 200 is focused on the bottom surface of the base material 101 so that the ultrasonic wave 201 from the sprayed coating 102 side. Is transmitted to the subject 100, and the degree of adhesion of the thermal spray coating 102 to the base material 101 is determined from the intensity of the bottom surface echo. According to this method, when the adhesion at the interface is poor, the amount of reflected ultrasonic waves at the interface is large, and the echo from the base material bottom is reduced. When the adhesion at the interface is good, the mother Since the ultrasonic waves passing through the material 101 increase and the echo from the base material bottom surface increases, the adhesion at the interface can be determined. Further, the ultrasonic probe 200 is two-dimensionally scanned along the surface of the subject 100, the bottom surface echo level is captured at an appropriate scanning pitch, and the C-scope image is formed.
Can be obtained.

[0005] In the thermal spray coating evaluation method described in the above-mentioned known example, the test object 100 and the focusing type ultrasonic probe 200 are arranged to face each other in water, but the ultrasonic test is performed between the test object and the ultrasonic probe. As means for interposing water as a sonic medium, other than this, for example, JP-A-53-9308
As described in Japanese Unexamined Patent Application Publication No. 4 (1999) -2004, a water supply hole penetrating up to the lens curvature surface of the acoustic lens is opened inside the ultrasonic probe, and the water supply hole is provided between the lens curvature surface of the acoustic lens and the subject. There is also a method of supplying water locally.
An ultrasonic probe having such a water supply hole is referred to as a “local water immersion ultrasonic probe” in this specification.

When a local water immersion type ultrasonic probe is used,
The need for a water tank for placing the subject and the ultrasonic probe is eliminated, so the ultrasonic inspection device can be downsized, and large members that could not be ultrasonically inspected because they could not fit in the water tank. Ultrasonography is also possible. In addition, since it is possible to work while holding the ultrasonic probe in a hand, it becomes possible to perform an operation in a narrow space or to perform an ultrasonic inspection on a curved surface, and to expand an object of the ultrasonic inspection.

[0007]

The method for evaluating a sprayed coating described in the above-mentioned known example is based on the ultrasonic wave 201 from the sprayed coating 102 side.
Is transmitted to the subject 100, and the bottom surface echo level of the base material 101 is detected. Therefore, as shown in FIG. 10A, as the thickness h of the base material 101 increases, the intensity of the ultrasonic beam on the surface of the thermal spray coating 102 increases. The irradiation diameter d increases, and the ability to detect defects decreases.

For the same reason as described above, the thermal spray coating evaluation method described in the above-mentioned known example shows a case where the ultrasonic probe 200 is two-dimensionally scanned along the surface of the subject 100, as shown in FIG. As shown, a relatively large area where the irradiation range of the ultrasonic beam deviates from the end e of the subject 100 produces a defect inspection impossible area. The end e of the subject 100
Is a location where defects in the thermal sprayed coating 102 are likely to occur, and is particularly important as an inspection location. Therefore, having such a large defect-inhibitable area is particularly problematic in improving the reliability of the defect inspection.

The thermal spray coating evaluation method described in the above-mentioned known example is a method for indirectly evaluating the adhesion between the base material 101 and the thermal spray coating 102 from the bottom surface echo level of the base material 101. In the bottom echo of the thermal spray coating 10
In addition to the information indicating the adhesiveness of No. 2, various information indicating the state of the inside and the bottom surface of the base material 101, for example, information on irregularities on the bottom surface, rust attached to the bottom surface, and defect information inside the base material are included. Therefore, such information cannot be separated from the information on the adhesion of the thermal spray coating 102, and there is a problem that the thermal spray coating cannot be accurately evaluated.

For the same reason as described above, the method for evaluating a thermal sprayed coating described in the above-mentioned known example is sufficient when the base material 101 is made of a material having a large attenuation of ultrasonic waves, such as a nickel-based superalloy. A complete or no bottom echo is obtained, and a practically sufficient defect inspection of the sprayed coating cannot be performed.

In the above description, the defect inspection of the thermal sprayed coating has been described as an example. However, the presence or absence of cracks in the surface layer of the test object, the stress distribution, the fracture toughness value, the thermal embrittlement or the grain boundary corrosion of the test object surface layer are examined. Similar inconveniences arise when assessing other health aspects of the subject surface, such as detection.

Further, the thermal spray coating evaluation method described in the above-mentioned known example is characterized in that the test object 100 and the focused ultrasonic probe 200
The ultrasonic inspection device needs to be equipped with a water tank because it is placed opposite to the underwater, and the ultrasonic inspection device becomes large, and the ultrasonic inspection is performed only for a subject large enough to be stored in the water tank. There is an inconvenience that it cannot be performed, and the versatility is poor.

On the other hand, in the local water immersion type ultrasonic probe according to the above-mentioned known example, since the water supply hole is opened outside the setting portion of the vibrator, the ultrasonic probe becomes larger in size than the case without the water supply hole, It is not said that it has sufficient handling easiness for practical use, and it has a cylindrical acoustic lens with a large curvature of the lens curvature surface as well as limited application places such as restricted use in a narrow space. When applied to a conventional ultrasonic probe, it is difficult to stably supply an ultrasonic medium between the lens curvature surface and the subject, and it is difficult to perform a good ultrasonic inspection.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the deficiencies of the prior art, and has as its object to provide a local water immersion type ultrasonic probe capable of performing a more accurate ultrasonic inspection with a smaller size. And to evaluate the soundness of the surface of the subject with high accuracy up to the end of the subject regardless of the thickness of the base material, the bottom surface condition, and the type of the material, etc. An object of the present invention is to provide a possible ultrasonic inspection apparatus.

[0015]

According to the present invention, there is provided an ultrasonic probe comprising: a vibrator;
An acoustic lens that focuses the ultrasonic waves transmitted from the transducer and enters the subject, and an ultrasonic medium supply path that supplies an ultrasonic medium between the lens curvature surface of the acoustic lens and the subject. In the provided local water immersion ultrasonic probe,
At the center of the vibrator and the acoustic lens, a through-hole is formed that penetrates from the upper surface of the vibrator to the lens curvature surface of the acoustic lens, and an ultrasonic medium supply path is set in the through-hole. .

Thus, a through hole is formed in the center of the vibrator and the acoustic lens from the upper surface of the vibrator to the lens curvature surface of the acoustic lens, and an ultrasonic medium supply path is formed in the through hole. When set, there is no need to provide a special space for forming an ultrasonic medium supply path in the ultrasonic probe, so that the ultrasonic probe can be miniaturized. The ease of use in space can be improved.

On the other hand, with respect to an ultrasonic inspection apparatus, the present invention provides an ultrasonic scanning section for scanning an ultrasonic wave on the surface of a subject via an ultrasonic medium, a driving section for the ultrasonic scanning section, and a driving section for the ultrasonic scanning section. The ultrasonic scanning unit is controlled via, and an ultrasonic inspection apparatus having an arithmetic processing unit that performs a defect inspection of the surface layer of the subject, comprising a local immersion ultrasonic probe in the ultrasonic scanning unit, An ultrasonic medium introduced from the outside into the ultrasonic medium supply path of the local water immersion ultrasonic probe is supplied between the lens curvature surface of the acoustic lens and the object, and the ultrasonic medium is supplied from the ultrasonic probe to the object. The transmission of the oblique incident wave for exciting the leaky surface acoustic wave to the sample and the reception of the leaky wave from the subject by the ultrasonic probe, and the reception level of the leaky wave received by the ultrasonic probe From the subject surface layer The soundness and the configuration of evaluating by said arithmetic processing section.

[0018] As shown in FIG. 6 (b), of the ultrasonic waves transmitted from the ultrasonic probe 1, through the bevel path A → B → C on the surface of the sprayed coating S ₂ in Rayleigh critical angle theta _L oblique incident wave incident is converted into LSAW, travels along the surface of the sprayed coating S _2. The leaky surface wave, leaky wave leaked by Rayleigh critical angle theta _L, leaked in point D of the object surface while propagating the surface of the thermal spray coating S ₂ from the incident point C, the route D → E → F Vibrator 2 through
Is received. Incidentally, leaky surface acoustic wave, the surface of the object S (in the case of this example, the surface of the sprayed coating S ₂₎ 1 wavelength order of, are to penetrate into the subject S.

[0019] When adhesion of the thermal sprayed coating S ₂ against the base material S ₁ is a good, since the amount of penetration into the base material S ₁ of the leaky surface acoustic wave has penetrated into the subject S is increased, the vibration The level of the leaky wave received by the child 2 becomes lower. On the other hand, the thermal spray coating S _{2 on the} base material S ₁
If adhesion is poor, the base material S ₁ and a thermal spray coating S ₂
Air layer caused by the separation between the penetration amount of the base material S ₁ of LSAW to LSAW at the interface is reflected between the air layer and the sprayed coating S ₂ becomes small,
The level of the leakage wave received by the vibrator 2 becomes relatively large. Therefore, it is possible to determine the adhesion of the quality of the thermal spray coating S ₂ against the base material S ₁ by the arithmetic processing unit than the receiving level of the leaky waves in the ultrasonic probe 1.

On the other hand, in the case of a test object having no coating such as a thermal spray coating, if a defect such as a crack exists in the surface layer of the test object S, the propagation of the leaky surface acoustic wave in the surface layer of the test object S is reversed. Is hindered by cracks or the like, so that the level of the leaky wave received by the vibrator 2 decreases. On the other hand, when there is no defect such as a crack on the surface of the subject S, the propagation of the leaky surface acoustic wave on the surface of the subject S is not hindered by the crack or the like. The level of leaked waves increases. Therefore, also in this case, the soundness of the subject S can be determined by the arithmetic processing unit from the reception level of the leaky wave in the ultrasonic probe 1.

If the ultrasonic scanning unit is provided with the local water immersion type ultrasonic probe 1, a water tank for accommodating the ultrasonic medium is not required, so that the ultrasonic inspection apparatus can be miniaturized and the ultrasonic inspection apparatus can be miniaturized. Since there are no restrictions on the size and shape of the specimen, the versatility of this type of ultrasonic inspection apparatus is greatly improved.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of an ultrasonic probe according to the present invention will be described with reference to FIGS.
FIG. 1 is a sectional view of an ultrasonic probe according to an embodiment, and FIG.
Is a bottom view of the ultrasonic probe according to the embodiment, and FIG. 3 is a partial cross-sectional view showing the effect of the ultrasonic probe according to the embodiment.

As shown in FIGS. 1 and 2, an ultrasonic probe 1 of this embodiment comprises a vibrator 2, an acoustic lens 3, and an ultrasonic medium disposed at the center of the vibrator 2 and the acoustic lens 3. A supply pipe 4 and an upper electrode 2U provided on the vibrator 2
And a connection connector 6 electrically connected to the lower electrode 2L via a cable 5, a case 7 for integrally holding the components, and a filler 8 filled in the case 7. I have.

The vibrator 2 has an upper electrode 2U and a lower electrode 2L formed on an upper surface and a lower surface of a piezoelectric thin film 2P, respectively, and has a ring shape in plan view. The upper electrode 2U and the lower electrode 2L are connected to a pulser / receiver of an ultrasonic inspection apparatus via a cable 5, a connection connector 6, and an external connector (not shown) connected to the connection connector 6 (FIG. 4).

The acoustic lens 3 has a vibrator setting surface 3a formed in a flat shape and a lens curvature surface 3b formed in a spherical shape, and a through hole penetrating from the vibrator setting surface 3a to the lens curvature surface 3b in the center thereof. 3c is opened, and the planar shape is a ring shape. The diameter of the through hole 3 c is adjusted to a diameter substantially equal to the inner diameter of the vibrator 2, and the vibrator setting surface 3
The vibrator 2 is set concentrically on a by means such as bonding. The acoustic lens 3 is made of a material having a high ultrasonic wave propagation speed, such as aluminum.
The inner diameter of the vibrator 2 and the diameter of the through hole 3c are
Although it can be set arbitrarily in consideration of the required diameter of the ultrasonic medium supply pipe 4 as well, a required oblique incident wave is selectively transmitted from the ultrasonic probe 1 to the subject, and When a leaky surface acoustic wave is generated and the soundness of the surface layer of the subject is evaluated based on the reception level of the leaky wave leaking from the subject, transmission of a normal incident wave from the ultrasonic probe 1 to the subject and transmission from the subject are performed. In order to minimize reception of a vertically reflected wave to the ultrasonic probe 1 and obtain an echo signal with a high S / N ratio, it is preferable to maximize the transmission of oblique incident waves and leaky waves within a range that does not hinder the propagation. Is preferred. In this example, the plane shape of the vibrator 2 is formed in a ring shape, and a through hole 3c is formed in the acoustic lens 3 to eliminate the generation of a vertical wave. Further, the through hole of the vibrator 2 and the acoustic lens 3 The ultrasonic medium supply pipe 4 is set using the through hole 3c.

The ultrasonic medium supply pipe 4 has an outer diameter substantially equal to the inner diameter of the vibrator 2 and the diameter of the through hole 3c formed in the acoustic lens 3, and its tip is 2 and the acoustic lens 3, the lens curvature surface 3 b
Is set within. As shown in FIG. 1, the inner peripheral surface of the distal end portion of the ultrasonic medium supply pipe 4 can be chamfered to make the flow of the ultrasonic medium smooth. On the other hand, a tube 9 such as a rubber tube is connected to the other end of the ultrasonic medium supply pipe 4, and the tube 9 is connected to an ultrasonic medium (eg, water) not shown via a pump not shown.
Connected to a storage tank.

The case 7 is composed of a cylindrical housing 7a and a ring-shaped cap 7b. The acoustic lens 3 is provided at the lower end of the housing 7a, and is provided at the center of the cap 7b. The upper end of the ultrasonic medium supply pipe 4 penetrates the hole. The contact portion between the housing 7a and the cap 7b and the contact portion between the ultrasonic medium supply pipe 4 and the cap 7b are welded all around by laser beam welding or the like. The symbols B1 and B2 in FIG.
These welds are shown.

The filler 8 has a role as a damper material for suppressing the vibration of the vibrator 2 more than necessary and a role for fixing the vibrator 2, the acoustic lens 3 and the ultrasonic medium supply pipe 4 to the housing 7a. And a resin material or the like is used.

When an ultrasonic inspection of a subject is performed by using the ultrasonic probe 1 configured as described above, as shown in FIG.
Are arranged to face each other, and a pump (not shown) is driven,
The ultrasonic medium stored in the tank is introduced into the tube 9 and the ultrasonic medium supply pipe 4, and is constituted by the lens curvature surface 3 b of the acoustic lens 3 and the subject S from the tip of the ultrasonic medium supply pipe 4. Supply in space. The surplus ultrasonic medium W flows out through a gap G provided between the ultrasonic probe 1 and the subject S. When the flow of the ultrasonic medium in the space is stabilized, the vibrator 2 is activated by a signal from a pulser / receiver (not shown) to execute a required ultrasonic inspection. A specific ultrasonic inspection method will be described later in detail.

The ultrasonic probe 1 according to the present invention comprises an ultrasonic medium W from the center of the vibrator 2 and the acoustic lens 3 in the space.
3, the water pressure of the ultrasonic medium W filled in the space uniformly acts on the entire surface of the lens curvature surface 3b, as schematically shown by an arrow in FIG. Therefore, the air layer does not remain on a part of the lens curvature surface 3b, and the ultrasonic beam transmitted to the subject S and the ultrasonic beam returning to the ultrasonic probe are not blocked by the air layer. Therefore, a highly accurate ultrasonic inspection result can be obtained.

Hereinafter, an embodiment of an ultrasonic inspection apparatus provided with the ultrasonic probe 1 having the above-described configuration and an example of an ultrasonic inspection method using the ultrasonic inspection apparatus will be described with reference to FIGS. I do. Here, FIG. 4 is a block diagram of the ultrasonic inspection apparatus, FIG. 5 is a perspective view showing a part of the ultrasonic scanning section, and FIG.
FIG. 7 is an explanatory diagram showing a method for positioning the ultrasonic probe in the Z direction, FIG. 7 is a flowchart showing the procedure of the ultrasonic inspection method, and FIG. 8 is a diagram showing an example of a C-scope image obtained by the ultrasonic inspection device.

As shown in FIGS. 4 and 5, the ultrasonic inspection apparatus according to the present embodiment includes an ultrasonic scanning unit 10 for two-dimensionally scanning ultrasonic waves along the surface of the subject S, and the drive unit 20, via the drive unit 20 controls the ultrasonic scanning unit 10, the adhesion distribution of the thermal spray coating S ₂ a reception level of incorporated at a suitable scanning pitch leaky wave and C scope images of It mainly comprises an arithmetic processing unit 30 for obtaining the soundness of the subject surface layer such as the presence or absence of cracks, and a display unit 40 for displaying a C scope image as an ultrasonic inspection result.

As shown in FIG. 5, the ultrasonic scanning unit 10
The ultrasonic probe 1, a gantry 11, a mechanical scanner 12 held by the gantry 11 and driving the ultrasonic probe 1 in a three-dimensional direction, and an ultrasonic medium for supplying the ultrasonic probe 1 are stored. The tank T and the tank T
And a pump P for supplying the ultrasonic medium stored in the ultrasonic probe to the ultrasonic probe 1. The mechanical scanner 12 includes the gantry 1
A pair of Y-axis guides 13 held in the Y-direction and held in the Y-direction, a Y-axis slider 14 guided by the Y-axis guide 13 in the Y-Y direction, and both ends fixed to the Y-axis slider 14 X-axis guide 1 arranged in the XX direction
5, an X-axis slider 16 guided in the X-X direction by the X-axis guide 15, a Z-axis guide 17 fixed vertically to the X-axis slider 16, and the ultrasonic probe 1
And a Z-axis slider 18 guided by the Z-axis guide 17 in the Z-Z direction. The sliders 14, 16, 18 are driven by three motors M1 to M3. Each of these motors is provided with a position signal output device such as a rotary encoder, and the arithmetic processing unit 30 can detect coordinate signals of the sliders 14, 16, and 18.

The ultrasonic probe 1 includes the vibrator 2
The oblique incident wave that causes the surface acoustic wave to leak to the subject S and the reception of the leaky wave from the subject S are increased by increasing the inner diameter of the lens and the diameter of the through hole 3c formed in the acoustic lens 3 to some extent. It is possible to use the one adjusted so as to suppress transmission of the vertically incident wave to the subject S and reception of the vertically reflected wave from the subject S as much as possible.

The driving section 20 includes a pulsar / receiver 21 for transmitting an ultrasonic wave from the ultrasonic probe 1 and receiving an ultrasonic wave by the ultrasonic probe 1, and digitally converts a signal received by the pulsar / receiver 21. An A / D converter 22 and a motor driver 23 for driving three motors M1 to M3 provided in the mechanical scanner 12 are provided.

The arithmetic processing unit 30 includes a CPU 31
And input means 32 such as a keyboard and a mouse, a trigger 33 and a motor controller 34 driven by a command from the input means 32, and an A / D-converted received signal to a motor via the motor driver 23 and the motor controller 34. A first memory 35 that stores together with the coordinate signals fetched from M1 to M3, a timer 36 that is activated by a signal from the trigger 33 and sets a gate for signal processing by the CPU 31, and a second memory that stores a signal processing procedure by the CPU 31. And two memories 37.

Hereinafter, an example of an ultrasonic inspection method using the ultrasonic inspection apparatus configured as described above will be described with reference to FIGS.

First, the input means 32 is operated to drive the motors M1 and M2 provided in the mechanical scanner 12, so that the ultrasonic probe 1 with respect to the subject S in the X-X direction and the Y-
Positioning in the Y direction is performed (procedure S1 in FIG. 7). The XX coordinates and the YY coordinates of the ultrasonic probe 1 at this time are taken into the first memory 35 via the motor driver 23 and the motor controller 34, and the current position of the ultrasonic probe 1 is specified.

Next, the input means 32 is operated to drive the motor M3 provided in the mechanical scanner 12 to move the ultrasonic probe 1 attached to the Z-axis slider 18 of the mechanical scanner 12 in the Z direction. As a result, FIG.
As shown in FIG. 7B, the focal point of the acoustic lens 3 is adjusted to be lower than the surface of the subject S by a required defocus amount ΔZ (step S2 in FIG. 7). That is, as shown in FIG. 6A, when the focal point of the acoustic lens 3 coincides with the surface of the subject S, the echo level of the leaked wave becomes maximum. , The focus of the acoustic lens 3 can be made to coincide with the surface of the subject S by lowering the ultrasonic probe 1 from the position by a required defocus amount ΔZ. The focus of the acoustic lens 3 can be matched to a predetermined position. This operation is performed by the arithmetic processing unit 30
Automatically on the basis of the program stored in the second memory 37 provided in the program. Since the defocus amount [Delta] Z is too large thermal spray coating S ₂ by LSAW attenuation is large is by leaky wave level decreases, when the thickness of the thermal spray coating of 0.1 mm, the defocus amount [Delta] Z 0 It is preferably about 0.2 mm.

Further, the input means 32 is operated to drive the pump P, and the ultrasonic medium stored in the tank T is passed through the tube 9 and the ultrasonic medium supply pipe 4 to the lens curvature surface 3b of the acoustic lens 3. And the subject S (step S3 in FIG. 7).

When the flow of the ultrasonic medium in the space is stabilized, the input means 32 is operated and the pulsar / receiver 2 is operated.
A signal is transmitted from the device 1 to drive the vibrator 2 (step S4 in FIG. 7). As shown in FIG. 6 (b), of the ultrasonic wave transmitted from the transducer 2, beveled incident at Rayleigh critical angle theta _L on the surface of the sprayed coating S ₂ through the bevel path A → B → C The incident wave is converted into a leaky surface acoustic wave, and the sprayed coating S
₂ along the surface. This leaky surface acoustic wave is
Leaks in Rayleigh critical angle theta _L while the incident point C propagating surface of the thermally sprayed coating S _2, leaky waves leaking at point D of the object surface, the transducer 2 via path D → E → F Received.

After the vibrator is activated, the input means 32 is operated to scan the ultrasonic probe 1 two-dimensionally in the X and Y directions within a required range, and at the same time, the ultrasonic probe 1 produces echo images of leaked waves at a required scanning pitch. Are taken into the first memory 35 provided in the arithmetic processing unit 30 together with the coordinate signal (step S5 in FIG. 7). This operation is also performed by the second memory 3 provided in the arithmetic processing unit 30.
7 can be performed automatically based on the program stored in.

Finally, the data stored in the first memory 35 is sequentially taken into the CPU 31 and converted into a C-scope image, and the result is displayed on the display unit 40 (procedure S in FIG. 7).
6). This operation can also be automatically performed based on a program stored in the second memory 37 provided in the arithmetic processing unit 30.

FIG. 8 shows a C-scope image of a leaky wave obtained by the apparatus according to the embodiment. FIG. 8 (a)
C of leaky waves obtained from subjects blasting sprayed coating S ₂ without being subject only to the central portion is formed as a pretreatment before the formation of the thermal spray coating S ₂ should be appreciated applied to the base material S ₁ an image, FIG. 8 (b), is normally sprayed coating S ₂ on the surface of the base S ₁ is formed, after the formation of the thermal spray coating S ₂ bending stress of leaky waves obtained from a subject loaded It is a C image.

[0045] In the example of FIG. 8 (a), and the echo level of the leaky wave in the central portion of the preform S ₁ which blasting was not performed becomes clearly higher than the normal portion around the embodiments it can be seen that can clearly visualize the peeling or adhesion deficiency of the thermal spray coating S ₂ at device according to an example.
Further, in the example of FIG. 8 (b), the echo level of the leaky wave in the central portion of the preform S ₁ is has appeared clearly lower striped echogram in comparison to the normal portion around, can not be observed with the naked eye minute It can be seen that cracks (width 2-5 μm) can be clearly imaged. In each case, the defect inspection could be performed up to the end e (see FIG. 6) of the subject S.

As described above, the ultrasonic inspection apparatus according to the present embodiment transmits the oblique incident wave for exciting the leaky surface acoustic wave to the subject S, receives the leaky wave from the subject S, Since the soundness of the surface of the subject is evaluated based on the reception level of the leaked wave, the soundness of the surface of the subject is highly accurately evaluated regardless of the thickness of the subject, the state of the bottom surface of the subject, and the internal state of the subject. can do. In addition, since the ultrasonic beam is focused on the surface layer of the subject S, it is possible to execute a required ultrasonic inspection up to the end of the subject. Further, since the ultrasonic inspection apparatus according to the present embodiment includes the local water immersion type ultrasonic probe, a water tank filled with an ultrasonic medium is not required, and the ultrasonic inspection apparatus can be downsized. Since the size and shape of the subject are not so limited, the applicable range of the ultrasonic inspection can be greatly expanded.

In the ultrasonic inspection apparatus according to the embodiment, a through hole 3c is formed in the center of the vibrator 2 and the acoustic lens 3 from the upper surface of the vibrator 3 to the lens curvature surface 3b of the acoustic lens 3. Was opened and provided with a local water immersion type ultrasonic probe in which the ultrasonic medium supply pipe 4 was disposed in the through hole 3c, but the gist of the present invention is not limited to this.
In addition, a local water immersion type ultrasonic probe having an arbitrary configuration can be provided.

In the ultrasonic inspection apparatus according to the embodiment, the ultrasonic probe 1 is used as a mechanical scanner.
Although the mechanical scanner 12 for transporting in the dimensional direction is provided, the gist of the present invention is not limited to this, and the configuration of the mechanical scanner is further simplified, for example, the ultrasonic probe 1 is transported in only one direction. Those can also be used.
Further, the mechanical scanner may be omitted, and the ultrasonic probe may be operated while being held in a hand. By omitting the mechanical scanner and operating the ultrasonic probe by hand, the configuration of the ultrasonic inspection apparatus can be greatly simplified, and the ultrasonic probe 1 can be arranged along a narrow space or along a curved surface.
Can be operated, so that the applicable range of the ultrasonic inspection can be further expanded.

The ultrasonic inspection apparatus according to the embodiment uses an ultrasonic probe having the vibrator 2 and the acoustic lens 3 having a ring-shaped planar shape, but the gist of the present invention is as follows. The present invention is not limited to this, and an ultrasonic probe having an array type or a single type of vibrator in a cylindrical lens type acoustic lens can also be used.

In the above-described embodiment, the ultrasonic inspection method has been described by taking the defect inspection of the thermal sprayed coating as an example.
Other soundness evaluations of the subject surface layer, such as stress distribution of the subject surface layer, fracture toughness, detection of thermal embrittlement or intergranular corrosion, can be performed in the same manner.

In addition, the ultrasonic probe 1 according to the above embodiment can be applied to the evaluation of the soundness of the surface of the subject using the leaky surface acoustic waves excited on the surface of the subject S.
The present invention can be applied to other ultrasonic examinations using longitudinal waves and transverse waves propagating in the subject S.

[0052]

According to the first aspect of the present invention, the ultrasonic medium is supplied from the center of the vibrator and the acoustic lens into the space formed between the lens curvature surface of the acoustic lens and the subject. Therefore, the ultrasonic probe can be reduced in size as compared with the case where the setting section of the transducer and the supply path of the ultrasonic medium are separately arranged, and the handling becomes easy,
Use in a narrower space becomes possible. In addition, since the pressure of the ultrasonic medium supplied into the space can be uniformly applied to the entire surface of the lens curvature surface, the air layer does not remain on a part of the lens curvature surface, and Since the transmitted ultrasonic beam and the ultrasonic beam returning to the ultrasonic probe are not interrupted by the air layer, a highly accurate ultrasonic inspection result can be obtained.

According to the invention of claim 2 of the present application, the vibrator and the acoustic lens can transmit an oblique incident wave for exciting a leaky surface acoustic wave to the subject and receive a leaky wave from the subject. Since it is configured, it has the same effect as the invention according to claim 1 of the present application, and is applied to an ultrasonic inspection for evaluating the soundness of the surface of a subject using a leaky surface acoustic wave excited on the surface of the subject. be able to.

According to a third aspect of the present invention, an oblique incident wave for exciting a leaky surface acoustic wave is transmitted to a subject, a leaky wave from the subject is received, and the subject is detected based on a reception level of the leaky wave. Since the soundness of the surface layer is evaluated, the soundness of the surface layer of the object can be evaluated with high accuracy regardless of the thickness of the object, the state of the bottom surface of the object, the internal state of the object, and the like. In addition, since the ultrasonic beam is focused on the surface layer of the subject, it is possible to execute a required ultrasonic test up to the end of the subject. Furthermore, since a local water immersion type ultrasonic probe is provided as an ultrasonic probe for transmitting an ultrasonic beam to a subject, a water tank filled with an ultrasonic medium is not required, and the ultrasonic inspection apparatus can be downsized. At the same time, the size and shape of the subject are not so limited, so that the applicable range of the ultrasonic inspection can be greatly expanded.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an ultrasonic probe according to an embodiment.

FIG. 2 is a bottom view of the ultrasonic probe according to the embodiment.

FIG. 3 is a partial cross-sectional view illustrating an effect of the ultrasonic probe according to the embodiment.

FIG. 4 is a block diagram of the ultrasonic inspection apparatus according to the embodiment.

FIG. 5 is a perspective view, partly in section, of an ultrasonic scanning unit provided in the ultrasonic inspection apparatus according to the embodiment.

FIG. 6 is an explanatory diagram showing a method of positioning the ultrasonic probe in the Z direction.

FIG. 7 is a flowchart illustrating an example of a procedure of an ultrasonic inspection method using the ultrasonic inspection apparatus according to the embodiment.

FIG. 8 shows C obtained by the ultrasonic inspection apparatus according to the embodiment.
It is a figure showing an example of a scope image.

FIG. 9 is an explanatory view showing a conventionally known ultrasonic inspection method for a thermal sprayed coating.

FIG. 10 is an explanatory diagram showing deficiencies of the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Transducer 3 Acoustic lens 3a Transducer setting surface 3b Lens curvature surface 3c Through hole 4 Ultrasonic medium supply pipe 5 Cable 6 Connector 7 Case 8 Filling material 9 Tube 10 Ultrasonic scanning unit 11 Mount 12 Mechanical Scanner 13 Y-axis guide 14 Y-axis slider 15 X-axis guide 16 X-axis slider 17 Z-axis guide 18 Z-axis slider 20 Drive unit 21 Pulser / receiver 22 A / D converter 23 Motor driver 30 Arithmetic processing unit 31 CPU 32 Input means 33 Trigger 34 Motor controller 35 First memory 36 Timer 37 Second memory 40 Display unit S Subject S ₁ Base material S ₂ Thermal spray coating

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G047 AA07 AB07 BB02 BB05 BC00 CB03 DA03 DB14 EA08 EA10 EA12 EA15 GB11 GB25 GG01 GG09 GG19

Claims (3)

[Claims] 1. An oscillator, an acoustic lens that focuses ultrasonic waves transmitted from the oscillator and enters an object, and an ultrasonic medium between a lens curvature surface of the acoustic lens and the object. In the local water immersion type ultrasonic probe having an ultrasonic medium supply path to be supplied, a through hole penetrating from the upper surface of the vibrator to the lens curvature surface of the acoustic lens is provided at the center of the vibrator and the acoustic lens. A local water immersion type ultrasonic probe, which is opened and an ultrasonic medium supply path is set in the through hole. 2. The local water immersion ultrasonic probe according to claim 1, wherein the vibrator and the acoustic lens transmit an oblique incident wave for exciting a leaky surface acoustic wave to the subject and the subject. A local immersion ultrasonic probe characterized in that it is capable of receiving leaky waves from a computer. 3. An ultrasonic scanning unit that scans an ultrasonic wave on the surface of a subject via an ultrasonic medium, a driving unit of the ultrasonic scanning unit, and controlling the ultrasonic scanning unit via the driving unit. And
An ultrasonic inspection apparatus comprising: an arithmetic processing unit that performs a defect inspection of a surface of an object; an ultrasonic inspection unit that includes a local immersion ultrasonic probe in the ultrasonic scanning unit; An oblique angle that excites a leaky surface acoustic wave from the ultrasonic probe to the subject while supplying the ultrasonic medium introduced into the acoustic medium supply path between the lens curvature surface of the acoustic lens and the subject. Performs transmission of an incident wave and reception of a leaky wave from the subject by the ultrasonic probe, and calculates the soundness of the subject surface layer from the reception level of the leaky wave received by the ultrasonic probe. An ultrasonic inspection device characterized in that it is evaluated by a section.