JP2010107488A - Ultrasonograph - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonograph which uses ultrasonic wave to nondestructively detect and image any detached area present on the surface of an measuring object, interfacial surface between film and base material, etc. <P>SOLUTION: In this ultrasonograph, signal generated by an ultrasonic signal generator 2 is amplified by an ultrasonic signal amplifier 3 to be entered into the measuring object 30 from an ultrasonic transmission probe 4 and an ultrasonic transceiver probe 6. The probe 6 receives surface vertical reflected wave, while an ultrasonic receiving probe 5 receives surface wave propagated through surface layer, these received waves are recorded in a receiving amplifier 8 and a waveform memory section 10. A waveform processor 12 calculates time difference in between surface vertical reflected wave and surface propagation wave to contrast the calculated result with guide wave dispersion curve computed by a guide wave rate dispersion curve calculation software 11 built in a personal computer 9, changing any propagation time difference beyond predefined threshold range into color tone. Then an image display section 13 displays it to distinguish any detached area from healthy one on interfacial surface between film and base material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention uses ultrasonic waves propagating in a surface layer or a thin plate-like object to detect defects and gaps existing on the surface of the object to be measured, the film / substrate interface, and the laminated thin plate interface through non-contact or water. The present invention relates to a diagnostic apparatus that detects and images nondestructively.

  Coating materials such as coatings on the surface of metal materials, plating layers on the surface, heat-resistant plasma sprayed ceramic coatings, wear-resistant ceramics deposited films on the surface of press dies, clad plates made of dissimilar metals, and wood plywood are widely used in the industry. Yes.

In order to evaluate the properties of the films, the integrity of the formed films and the interface between the laminated boards, and the degree of adhesion, Japanese Industrial Standards define various peeling, scratching, and scratch test methods (Non-Patent Documents 1-4). .
About JIS K5600-5-4 scratch hardness (pencil method). JIS K5600-5-5 General test methods for paints-Part 5: Mechanical properties of paint film-Section 5: Scratch hardness (load needle method). JIS H 8504 Plating adhesion test method. JIS K7312 Physical testing method for thermosetting polyurethane elastomer moldings.

  However, any of the above test methods is a destructive test method that breaks the film, and therefore cannot be applied to plant components, products, molds, and tools.

In order to evaluate the characteristics or soundness without destroying the film, for example, an ultrasonic method (Patent Document 1), an eddy current method (Patent Document 2), and a microwave method (Patent Document 3) have been filed.
Japanese Patent Laid-Open No. 6-11868 JP 2005-208061 A Japanese Patent Laid-Open No. 2007-303956

  However, since the method of Patent Document 1 directly presses the ultrasonic sensor against the surface to be measured and sweeps the transmission frequency to measure the resonance frequency, the method is easily influenced by the surface unevenness state and the acoustic coupling material. However, it is only possible to detect delamination of a considerably large area. On the other hand, the methods using eddy currents or microwaves disclosed in Patent Document 2 and Patent Document 3 that are non-contact measurement are easily affected by lift-off (distance between the surface of the object to be measured and the sensor), and are difficult to measure in the field. Has the problem.

  Furthermore, each of the above methods can be applied when the object to be measured is planar, but for a surface having a curvature, such as the surface of a circular tube or the inner surface of a cylinder, the variation in measurement results increases due to the effect of lift-off. Has a problem.

  In view of the above circumstances, the present invention provides a coating film on a metal material surface, a plating layer on the surface, a plasma sprayed ceramic coating, a wear-resistant ceramic vapor deposition film on the surface of a press mold, a clad plate of a dissimilar metal, a wood plywood, and the like. It is an object of the present invention to provide an ultrasonic diagnostic apparatus capable of evaluating the soundness of a substrate interface using an air propagation ultrasonic method or a water immersion ultrasonic method.

  In order to achieve the above object, the solution adopted by the present invention includes an ultrasonic signal generating unit and an ultrasonic signal amplifying unit for electrically amplifying an electric signal generated by the generating unit and applying the electric signal to the ultrasonic transmitting unit. An ultrasonic transmission unit for injecting an electric signal amplified by the amplification unit into the object to be measured to excite a surface wave and a surface vertical reflected wave, and a surface wave wave and a surface propagating near the surface of the object to be measured. An ultrasonic receiving unit for detecting vertical reflected waves; a reception amplifying unit for amplifying a received signal received by the ultrasonic receiving unit; and a waveform storage unit for digitally converting the signal amplified by the receiving amplifying unit and recording it digitally A scanning mechanism that moves both of the ultrasonic transmitter and the ultrasonic receiver relative to the object to be measured based on an output signal from a scanning mechanism drive signal generator built in the personal computer, personal A waveform processing unit and an image display unit built in the computer, and guide wave velocity dispersion curve calculation software, and the electrical signal generated by the ultrasonic signal generation unit based on a command from the personal computer A surface that is amplified by an ultrasonic signal amplifying unit, excites the ultrasonic transmitting unit by the amplified electric signal, and enters a surface wave and a surface vertical reflected wave on the object to be measured, and propagates in the vicinity of the surface of the object to be measured. The wave wave and the surface vertical reflected wave are received by the ultrasonic wave receiving unit, the received signal is amplified by the receiving amplification unit, and then digitally converted by a high-speed A / D conversion board, and the digital waveform is converted into the digital waveform. The difference between the surface vertical reflected wave arrival time and the surface wave propagation time is calculated by the waveform processing unit from the recorded waveform, and the difference is calculated from the recorded waveform. The image display unit uses different colors depending on whether it deviates from the threshold range of the propagation time calculated in advance from the theoretical surface wave velocity or guide wave velocity using the wave velocity dispersion curve calculation software. In addition, it is possible to identify the presence or absence of a defect by imaging at a high speed a peeling portion that exists immediately below the surface of the object to be measured by color mapping each scanning position scanned by the scanning mechanism. And

  The ultrasonic transmission unit includes a planar ultrasonic probe, a focused ultrasonic probe, an air ultrasonic probe, an array ultrasonic sensor, a YAG laser, an air jet, or a giant magnetostrictive probe. By selecting, it is possible to cope with the diagnosis of various coating / substrate combinations.

  Diagnosis of various coating / substrate combinations by selecting one of a piezoelectric ceramic element, a piezoelectric polymer element, an air ultrasonic probe, an array sensor, or a laser Doppler displacement meter as the ultrasonic receiver. It can correspond to.

  Since the scanning mechanism can move along one-dimensional, two-dimensional, cylindrical inner surface, cylindrical inner / outer surface, and truncated cone inner / outer surface, it can cope with diagnosis of coating / substrate combinations of these various shapes.

  According to the present invention, ultrasonic waves are transmitted and received at a distance of several tens of millimeters from an object to be measured using an air ultrasonic probe, a water immersion surface wave probe, etc. Means for detecting and imaging have been established.

  For a deposited coating film having a thickness of several microns, the soundness of the coating film and the substrate interface can be evaluated nondestructively using a water immersion surface wave probe having a frequency of several tens of MHz.

  For plating layers and coating films with a thickness of several tens of microns, non-destructive evaluation of the integrity of the coating film / substrate interface is performed using a water immersion surface wave probe or air ultrasonic probe with a frequency of several MHz. it can.

  For thermal sprayed ceramic coatings with thicknesses of several hundred microns, resin linings with thicknesses of the order of millimeters, and clad plates, using an air ultrasonic probe with a frequency of several tens to several hundreds of kHz, the integrity of the coating and substrate interface Can be evaluated nondestructively.

  When air ultrasonic waves with a frequency of several hundred kHz are used, even if the surface of the object to be measured has an unevenness of the order of 0.1 mm, ultrasonic waves can be sent and received as it is, so the ultrasonic incident surface is grindered as in the conventional ultrasonic flaw detection method. There is no need for smoothing.

  When an air ultrasonic probe is used, it can excite surface waves or guide waves of CFRP, plastic materials, wood, etc., which have a propagation velocity slower than underwater sound velocity and faster than airborne sound velocity, which cannot be measured by contact-type or water-immersion ultrasonic methods. be able to.

  A best mode for detecting an internal defect in a non-contact manner using the present invention will be described below based on an embodiment with reference to the drawings.

  FIG. 4 is a diagram for explaining an air ultrasonic diagnostic apparatus using an air ultrasonic probe. The air ultrasonic diagnostic apparatus 1 includes a surface wave air ultrasonic wave transmission probe 4, a surface wave air ultrasonic wave reception probe 5, and a surface vertical reflected wave air ultrasonic wave transmission / reception integrated probe for transmitting and receiving surface vertical reflected waves. The probe 6, the ultrasonic signal generator 2 that sends electrical signals to them, the ultrasonic signal amplifier 3 that amplifies the signals, and the air ultrasonic probes 4 to 6 are relative to the object to be measured 30. An ultrasonic probe scanning mechanism 7 that performs positioning while moving to the position, a reception amplifying unit 8 that amplifies signals received by the air ultrasonic reception probes 5 and 6, and a supercomputer built in the personal computer 9. Waveform storage for storing waveforms using a scanning mechanism drive signal generator 14 for generating a signal for driving the acoustic probe scanning mechanism 7 and a high-speed A / D conversion board for converting the amplified analog signal into a digital signal. Part 10, guide wave velocity dispersion curve It is configured to include a calculation software 11 and the waveform processing section 12, and the image display unit 13.

  FIG. 5 is a diagram illustrating a water immersion ultrasonic diagnostic apparatus using a water immersion surface wave probe. The water-immersion ultrasonic diagnostic apparatus 1A is immersed in a water tank 50 together with the object to be measured 30, and integrates a surface wave ultrasonic transmission probe, a surface wave ultrasonic reception probe, and a surface vertical reflected wave transmission / reception function. The immersion surface wave probe 40, the ultrasonic signal generation unit 2 that sends an electrical signal thereto, the ultrasonic signal amplification unit 3 that amplifies the signal, and the immersion surface wave probe 40 are attached to the object to be measured 30. An ultrasonic probe scanning mechanism 7 that performs positioning while relatively moving, a reception amplifying unit 8 that amplifies a signal received by the water immersion surface wave probe 40, and an ultrasonic wave incorporated in the personal computer 9. A scanning mechanism drive signal generator 14 that generates a signal for driving the probe scanning mechanism 7 and a waveform storage unit that stores a waveform using a high-speed A / D conversion board that converts the amplified analog signal into a digital signal. 10. Guide wave velocity dispersion curve calculation Futouea 11, and includes a waveform processing section 12 and the image display unit 13 is constituted.

  In the immersion ultrasonic diagnostic apparatus 1A shown in FIG. 5, the immersion surface wave probe 40 shown in FIG. 3 is used, so that the longitudinal wave reflected wave perpendicular to the object to be measured 30 is automatically excited and received. Therefore, three probes as shown in FIG. 4 are not required. In addition, as an ultrasonic transmission probe, a plane ultrasonic probe, a focused ultrasonic probe, an air ultrasonic probe, an array ultrasonic sensor, a YAG laser, an air jet, or a giant magnetostrictive probe Any of these can be selected, and a piezoelectric ceramic element, a piezoelectric polymer element, an air ultrasonic probe, an array sensor, or a laser Doppler displacement meter can be selected as the ultrasonic receiving probe. can do.

  By the way, in the ultrasonic diagnostic apparatus shown in FIG. 4 and FIG. 5, the physical property value and the plate thickness (when healthy) or the film of the film and the base material are calculated by the guide wave velocity dispersion curve calculation software 11 built in the personal computer 9. When the thickness (when there is a peeling portion) is input, guide wave velocity dispersion curves in various modes are displayed as a function of frequency × plate thickness / film thickness as shown in FIG.

  As shown in FIG. 2A, when the film 32 and the base material 31 of the object to be measured 30 are joined firmly, the surface wave velocity that propagates the plate thickness of the object to be measured 30 is as shown in each curve of FIG. Asymptotic value (given in the right end square box W1 in FIG. 1).

As shown in FIG. 2 (B), when the separation part 33 exists between the film 32 and the base material 31 in the object to be measured 30, the film thickness of the separation part is soundly coupled. Since the thickness of the object to be measured 30 is one tenth or less of the thickness, the value of the frequency × film thickness becomes small, and as shown in the left end square frame W2 in FIG. A low-speed A ₀ mode wave accompanied with a ₀ mode and bending deformation propagates in the separated film thickness.

Whether the A ₀ mode or S ₀ mode guide wave propagating through the peeling portion 33 is measured in the measurement state of FIG. 2B is defined by the physical properties of the film, the thickness, and the outline of the peeling portion. Depends on amplitude.

The propagation time of the surface wave when there is no separation shown in FIG. 2 (A) is the sum of the air propagation time that does not depend on the presence or absence of separation and the time for propagation through the healthy part at the surface wave velocity. The propagation time of the surface wave / guide wave shown in FIG. 2 (B) including the separation part is the air propagation time that does not depend on the presence or absence of separation, the time to propagate the healthy part at the surface wave velocity (V _R ), and the separation part. This is the sum of the propagation times at the speed (V _G ) of the S ₀ or A ₀ mode.

The difference between the above two propagation times is expressed by the following equation.
Formula (1) ··· t = (L−d) / V _R + d / V _G

For example, the separation portion 33 having the length “d” is ½ of the propagation distance L of the surface wave / guide wave, and the velocity V _G (5400 m / s) of the S ₀ mode is the surface wave as shown in FIG. When the velocity V _R (3000 m / s) is 1.8 times, the ratio of the propagation time including the separation portion 33 of FIG. 2B to the healthy portion propagation time of FIG. 2A is about 0.78 (78 %). If the current digital waveform processing apparatus is used, a propagation time difference of about 1% can be easily calculated.

  In equation (1), the ultrasonic transmission is assumed as one line as shown in FIG. 2, but when an air ultrasonic probe of several hundred kHz is used, for example, the surface wave wavelength of steel is 7 mm. Therefore, in order to efficiently excite surface waves, an ultrasonic probe having a larger aperture is used. For this reason, it is difficult to accurately evaluate the distance L in Expression (1) before measurement.

In order to avoid this problem, a probe 6 for receiving the surface vertical reflected wave is provided, and the difference between the surface wave / guide wave reception time (t0 or t1 in FIG. 6) with respect to the surface vertical reflected wave is measured. 6 for each scanning position by color mapping with different colors within and outside the range of the “time threshold” calculated from the “speed threshold” shown in FIG. A relative propagation velocity difference image (peeling region image 60) as shown is obtained. The range of the “velocity threshold value” shown in FIG. 1 is set as a range of about ± 10% of the surface wave velocity (V _R ) of the healthy part in consideration of measurement errors and the like.

  In this method, the time of the surface vertical reflected wave received by the central surface vertical reflected wave air ultrasonic wave transmitting / receiving integrated probe 6 in FIGS. 2 (A) and 2 (B) is the surface wave measuring probe 4. , 5 is different from the sum of the propagation time in the air and the time for propagating the healthy part at the surface wave velocity by a certain value, so that the latter (the time for propagating the healthy part at the surface wave velocity) can be used instead of the latter.

  The ultrasonic diagnostic apparatus shown in FIGS. 4 and 5 shows an optimum measurement form, but as a simple form, the surface wave with respect to the surface vertical reflected wave (left wave packet) shown in FIG. The ultrasonic diagnostic apparatus may generate an alarm when the propagation time difference of (right wave packet) is out of a preset time difference range.

It is a conceptual diagram which shows a surface wave and guide wave velocity dispersion | distribution. It is a conceptual diagram of surface wave / guide wave measurement using an air ultrasonic probe. It is a conceptual diagram of surface wave / guide wave measurement using a water immersion surface wave probe. 1 is an explanatory diagram of the overall configuration of an air ultrasonic diagnostic apparatus using an air ultrasonic probe according to an embodiment. 1 is an explanatory diagram of the overall configuration of a water immersion ultrasonic diagnostic apparatus using a water immersion ultrasonic probe according to an embodiment. It is an example of the peeling area | region image by a propagation time difference map.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air ultrasonic diagnostic apparatus 1A Water immersion ultrasonic diagnostic apparatus 2 Ultrasonic signal generation part 3 Ultrasonic signal amplification part 4 Surface wave air ultrasonic transmission probe 5 Surface wave air ultrasonic reception probe 6 Surface vertical reflected wave Air ultrasonic transmission / reception integrated probe 7 Scanning mechanism 8 Reception amplification unit 9 Personal computer 10 Waveform storage unit 11 Guide wave velocity dispersion curve calculation software 12 Waveform processing unit 13 Image display unit 14 Scanning mechanism drive signal generation unit 30 Measured Object 31 Base material 32 Coating 33 Peeling part 40 Water immersion surface wave probe 50 Water tank 60 Peeling area image

Claims (3)

Ultrasonic signal generator, ultrasonic signal amplifier that electrically amplifies the electrical signal generated by the generator and applies it to the ultrasonic transmitter, and the electrical signal amplified by the amplifier enters the device under test An ultrasonic transmitter for exciting the surface wave and the surface vertical reflected wave respectively, an ultrasonic receiver for detecting the surface wave wave and the surface vertical reflected wave propagated near the surface of the object to be measured, and the ultrasonic wave A reception amplification unit that amplifies the reception signal received by the reception unit, a waveform storage unit that digitally converts the signal amplified by the reception amplification unit, and digital recording, and a scanning mechanism drive signal generation unit built in the personal computer A scanning mechanism that moves both the ultrasonic transmission unit and the ultrasonic reception unit relative to the object to be measured based on an output signal, and a waveform processing unit and an image display unit built in the personal computer. Comprising a guided wave velocity dispersion curve computation software, to,
The electrical signal generated by the ultrasonic signal generator based on a command from the personal computer is amplified by the ultrasonic signal amplifier, and the ultrasonic transmitter is excited by the amplified electrical signal to generate surface waves and The surface vertical reflected wave is incident on the object to be measured, the surface wave wave and the surface vertical reflected wave propagated in the vicinity of the surface of the object to be measured are received by the ultrasonic wave reception unit, and the received signal is received by the reception amplification unit. After each amplification, digital conversion is performed with a high-speed A / D conversion board, and the digital waveform is recorded in the digital waveform storage unit, and the difference between the surface reflected wave arrival time and the surface wave propagation time is calculated from the recorded waveform. The propagation time threshold calculated by the waveform processing unit and the difference is calculated in advance from the theoretical surface wave velocity or guide wave velocity using the guide wave velocity dispersion curve calculation software. Different colors are displayed depending on whether the value is out of the range or not, and displayed on the image display unit, and color mapping is performed for each scanning position scanned by the scanning mechanism so that it is directly below the surface of the object to be measured. An ultrasonic diagnostic apparatus characterized by identifying the presence or absence of a defect by imaging an existing peeling part at high speed.   The ultrasonic transmission unit may be any one of a plane ultrasonic probe, a focused ultrasonic probe, an air ultrasonic probe, an array ultrasonic sensor, a YAG laser, an air jet, or a giant magnetostrictive probe. The ultrasonic diagnostic apparatus according to claim 1, wherein:   3. The ultrasonic wave receiving unit is any one of a piezoelectric ceramic element, a piezoelectric polymer element, an air ultrasonic probe, an array sensor, and a laser Doppler displacement meter. The ultrasonic diagnostic apparatus as described.

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