JP6248183B2 - Ultrasonic inspection apparatus and ultrasonic inspection method - Google Patents

Description

  The present invention relates to an ultrasonic inspection apparatus and an ultrasonic inspection method.

  As a background art in this technical field, there is JP-A-2001-83125 (Patent Document 1). By superposing piezoelectric materials that vibrate in two orthogonal directions, applying a voltage to these piezoelectric materials to generate vibrations, and superimposing polarized waves orthogonal to the two directions, a super Generate sound waves. A method for measuring acoustic anisotropy of a material having acoustic anisotropy using transverse wave ultrasonic waves having an arbitrary polarization state and a material deterioration diagnostic apparatus using the method for measuring the acoustic anisotropy are described. Yes.

  Japanese Patent Application Laid-Open No. 2008-139325 (Patent Document 2) discloses that an ultrasonic probe having an ultrasonic transducer for longitudinal waves, which has been conventionally used, is used in the vertical direction, obliquely in the inspection object. Transverse waves oscillating in the same direction without mode conversion in the direction along the flaw detection surface or the direction along the flaw detection surface are transmitted from the two ultrasonic probes, respectively, and the reception time of each horizontal polarization transverse wave is determined by referring to the time delay value. It describes an ultrasonic flaw detector capable of performing flaw detection or plate thickness measurement of a material to be inspected with low-frequency ultrasonic waves by performing addition and analysis after correction.

JP 2001-83125 A JP 2008-139325 A

  The material described in Patent Document 1 is that material deterioration occurs by simultaneously generating two ultrasonic waves having orthogonal polarizations, measuring acoustic anisotropy, and measuring the transverse wave velocity from the bottom echo and the thickness of the DUT. Although it performs diagnosis, it does not have a focus function for detecting reflectors such as minute defects or inclusions. In order to detect a reflected wave from a minute defect or an inclusion, a focus function is required because it is necessary to be able to distinguish from a noise from an ultrasonic reflector existing in other surroundings. The thing of patent document 1 has a subject in using for a test | inspection with a good S / N (signal-to-noise ratio) by the point that a focus is not considered.

  In addition, the device described in Patent Document 2 arranges a plurality of longitudinal wave probes on a flaw detection surface to generate longitudinal wave ultrasonic waves, and also generates transverse wave ultrasonic waves as delayed echoes to strengthen waves by interference. However, there is no effect of focusing the transverse wave ultrasonic wave, and it is difficult to detect flaws by improving the S / N in distinction from noise from the ultrasonic reflector existing around the target minute defect or inclusion. There is. In addition, since the acoustic anisotropy is not taken into consideration, the sound speed varies depending on the generated ultrasonic vibration direction, and there is a problem that the accuracy of specifying the reflector position by the propagation time measurement is lowered.

  Accordingly, the present invention has been made in view of the above problems, and provides an ultrasonic inspection apparatus and an ultrasonic inspection method capable of detecting minute defects or inclusions present in a metal material with high accuracy. The purpose is to do.

To achieve the above object, the present invention provides a polarization control probe for generating a transverse wave ultrasonic wave having a first vibration direction and a transverse wave ultrasonic wave having a second vibration direction, a transverse wave ultrasonic wave having a first vibration direction, From the waveform generator that controls the phase difference of each transverse wave ultrasonic wave having the second vibration direction and the received waveform of the polarization control probe, the transverse wave ultrasonic wave having the first vibration direction and the transverse wave ultrasonic wave having the second vibration direction And a display for displaying the interference waveform obtained by the waveform analysis unit.

  ADVANTAGE OF THE INVENTION According to this invention, the ultrasonic inspection apparatus and ultrasonic inspection method which can detect the internal defect or inclusion of a to-be-inspected object with high precision can be provided.

1 is a block diagram illustrating an overall configuration of an ultrasonic inspection apparatus according to Embodiment 1. FIG. It is a conceptual diagram which shows the principle of the ultrasonic inspection used by a present Example. It is a conceptual diagram which shows the principle of the ultrasonic inspection used by a present Example. It is a graph of an example of the waveform which shows the principle of the ultrasonic inspection used by a present Example. It is a conceptual diagram which shows the effect of the frequency of the longitudinal wave ultrasonic inspection used by a present Example. It is a conceptual diagram which shows the effect of the frequency of the transverse wave ultrasonic inspection used by a present Example. It is a conceptual diagram which shows the effect of the acoustic anisotropy of the ultrasonic test | inspection used by a present Example. It is a graph of an example of the waveform which shows the effect of the acoustic anisotropy of the ultrasonic inspection used in a present Example. It is a conceptual diagram of propagation of the transverse wave ultrasonic wave in the material which has the acoustic anisotropy used in a present Example. It is a perspective view of the test | inspection form by Example 1. FIG. 3 is a flowchart illustrating an operation procedure according to the first exemplary embodiment. 1 is a perspective view of a polarization control probe in Example 1. FIG. It is detail drawing of the waveform generator contained in the waveform generation part of a present Example. It is a figure of an example of the polarization state which the polarization control probe used by a present Example produces | generates. It is a graph of an example of the probe output waveform and synthetic | combination waveform of a present Example. It is a graph of an example of the probe output waveform and synthetic | combination waveform of a present Example. It is a detailed view of a computing unit included in the waveform analysis unit of the present embodiment. FIG. 6 is a block diagram illustrating an overall configuration of an ultrasonic inspection apparatus according to a second embodiment. 6 is a perspective view of a polarization control probe according to Embodiment 2. FIG. FIG. 10 is a block diagram illustrating an overall configuration of an ultrasonic inspection apparatus according to a third embodiment. It is a perspective view of the test | inspection form by Example 3. FIG. 10 is a flowchart illustrating an operation procedure according to the third embodiment. FIG. 10 is a block diagram illustrating an overall configuration of an ultrasonic inspection apparatus according to a fourth embodiment. It is a perspective view of the test | inspection form by Example 4. FIG.

  Ultrasonic flaw detection is used to nondestructively inspect internal defects or inclusions in metal materials. In a conventional ultrasonic flaw detection inspection that generates ultrasonic waves (longitudinal wave ultrasonic waves) that travel in a direction perpendicular to the flaw detection surface of the material to be inspected, the S / of reflected waves from the internal defects or inclusions to be inspected. In order to improve N (signal-to-noise ratio), flaw detection is performed on a test object submerged in water by focusing a higher-frequency longitudinal wave ultrasonic wave by mechanical scanning.

  However, in such a high-frequency ultrasonic inspection using longitudinal ultrasonic waves, if the ultrasonic frequency increases, the cost of the oscillator increases and the attenuation of longitudinal ultrasonic waves in the material to be inspected increases. There is a problem that the S / N of the signal is lowered or it is difficult to improve the accuracy of mechanical scanning for focusing on a defect or an inclusion.

  In order to solve this problem, it is conceivable to use transverse wave ultrasonic waves. If the transverse wave ultrasonic wave is used, the sound speed of the transverse wave ultrasonic wave is about half that of the longitudinal wave ultrasonic wave. Therefore, it is advantageous to obtain the same measurement accuracy at about half the frequency of the longitudinal wave ultrasonic wave.

  However, for example, when shear wave ultrasonic waves are used in a metal material having acoustic anisotropy, the metal material having acoustic anisotropy has a transverse wave sound velocity in the vibration direction (polarization: the polarization direction here is the vibration direction and This indicates that the phase is a transverse ultrasonic wave.) It is difficult to pinpoint the position of an intrinsic defect or inclusion without considering the acoustic anisotropy. . As an example, in roll-formed carbon steel, structure anisotropy and stress anisotropy occur in the rolling direction. When the propagation time of the transverse wave is measured with such a steel material, the propagation time that varies depending on the vibration direction of the ultrasonic wave is measured. Therefore, in order to detect minute defects or inclusions in a metal material having acoustic anisotropy, a flaw detection inspection considering the speed of sound depending on the vibration direction of the transverse wave polarization is required.

  In Patent Document 1 and Patent Document 2 described in the background art, although flaw detection using a transverse wave ultrasonic wave is described, the focus function is not described. Here, the focus function refers to a predetermined position to be detected by transmitting and receiving polarized waves, which are transverse wave ultrasonic waves having vibration direction components in two directions, so that the polarized waves interfere with each other at predetermined positions inside the inspection target. The control is performed so that the ultrasonic signals are strengthened and unnecessary signals at other positions are weakened.

  First, the ultrasonic inspection method used in the present invention will be briefly described with reference to FIGS.

  FIG. 2 is a conceptual diagram of the ultrasonic inspection method. In the ultrasonic inspection method, the longitudinal wave probe 110 or the transverse wave probe 111 that converts a voltage into a physical force causes the force to propagate to the inspected object 7 as a sound wave vibration. In the ultrasonic mode, a longitudinal wave 112 that vibrates in the same direction as the propagation direction and a transverse wave 113 that vibrates in a direction perpendicular to the propagation direction are both used (FIG. 2A). At this time, when a reflector 72 such as a defect or an inclusion is present in a sound path propagating through the inspection object 7, the reflector echo 101b reflected by the reflector is detected. If there is no reflector inside the inspection object 7, only the bottom surface echo 101c is detected by the bottom surface 71 of the inspection object (FIG. 2B). The position of the reflector is measured by the time interval 102 between the transmission wave 101a and the reflector echo 101b and the ultrasonic sound velocity in the specimen. The specimen thickness is measured by the time interval 103 between the transmission wave 101a and the bottom surface echo 101c and the ultrasonic sound velocity in the specimen. In some cases, a multiple reflection signal that is repeatedly reflected in the inspection object 7 is detected. For example, the reflector echo 101d is a reflection of the bottom echo on the surface and reflected again by the reflector 72, and the second bottom echo 101e is an echo in which the first bottom echo is reflected on the surface and reflected again on the bottom. It is. Similarly, the third and subsequent bottom echoes are detected (FIG. 2 (c)).

  FIG. 3 is a conceptual diagram showing the effect of frequency in ultrasonic inspection. When the frequency is high, the attenuation of the ultrasonic wave 113 in the material 7 to be inspected increases, and further, the echo 114 attenuates while propagating to the probe 111, and the S / N of the signal decreases (FIG. 3A). Therefore, if transverse wave ultrasonic waves are used, the sound velocity of the transverse wave ultrasonic waves is about half that of the longitudinal wave ultrasonic waves. Therefore, it is advantageous to obtain the same measurement accuracy at about half the frequency of the longitudinal wave ultrasonic waves. is there. However, since the low-frequency transverse wave ultrasonic wave 115 has a low reflectivity with respect to the minute reflector 72, only the reflection echo 116 having a small amplitude can be obtained, and the S / N of the signal is lowered (FIG. 3B). Therefore, in order to detect minute defects or inclusions present in the metal material with high accuracy, when using the transverse wave ultrasonic wave, the focus function can be used to catch the defects or inclusions more clearly. it can.

  FIG. 4A is a conceptual diagram of inspection in ultrasonic flaw detection using a transverse wave when the object to be inspected has acoustic anisotropy. When the transverse wave probe 111 is used and the inspection object 7 has acoustic anisotropy, the ultrasonic wave 113 vibrates in two principal axes depending on the transmitted ultrasonic wave 113 and the direction of the acoustic anisotropy of the inspection object 7. Therefore, the received waveform becomes a reflector echo 101b obtained by superimposing these two polarized waves, and the accuracy of reflector position identification by propagation time measurement is reduced. . FIG. 4B shows a graph of an example of a waveform showing the effect of acoustic anisotropy. In FIG. 4B, when the transmission wave 101a is transmitted from the transverse wave probe 111, the device under test 7 is divided into a polarized wave 113a and a polarized wave 113b due to acoustic anisotropy. Since the polarization 113a and the polarization 113b have different propagation speeds, a phase shift 104 occurs. This shift causes the reception waveform of the reflector echo 101b to be stretched when the polarization 113a and the polarization 113b are superimposed, and the reception waveform synthesized by the interference effect becomes weak. Since the phase shift 105 becomes larger in the bottom surface echo 101c, this influence becomes larger.

  FIG. 4C shows an outline of the propagation of the transverse wave ultrasonic wave in the material having acoustic anisotropy (the case where the transverse wave ultrasonic wave is transmitted in the direction from the front side to the back side of the sheet) is shown. When transmitting the ultrasonic wave 113 in a direction parallel to the principal axis of the material having acoustic anisotropy, only a single polarized wave is transmitted, so that no phase difference occurs in the received ultrasonic signal. The main axis shown here refers to the axial direction within the body to be inspected with the speed at which the transverse wave ultrasonic wave propagates the fastest or the axial direction within the body to be examined with the speed at which the transverse wave ultrasonic wave propagates the slowest. When transmitting the ultrasonic wave 113 in a direction inclined by 45 degrees with respect to the principal axis direction of the material having acoustic anisotropy, the ultrasonic wave is separated into the polarized wave 113a and the polarized wave 113b, and the propagation speed of the transverse wave in each axial direction is Because of the difference, the received waveform is synthesized with a phase difference between the polarized wave 113a and the polarized wave 113b. When the phase difference is shifted, the waveform is weakened and synthesized. Therefore, even if the same ultrasonic wave is transmitted, the intensity of the received waveform differs depending on the crystal axis direction of the inspected object 7 and the ultrasonic wave transmission direction. become. Therefore, if this principle is used, the direction (main axis direction) of the acoustic anisotropy of the inspection object 7 can be obtained. Further, if the phase difference between the polarization 113a and the polarization 113b is controlled using the principle that the propagation speed of the transverse wave is different in each axial direction, the combined waveform can be strengthened only at a predetermined location, and the focus function is improved. realizable.

  The present invention provides an inspection apparatus using a polarization-controllable probe in order to perform detection of a minute reflector having a good S / N in ultrasonic inspection using a transverse wave, using the principle described above.

  The overall configuration of the inspection apparatus according to the present embodiment will be described with reference to FIGS. 1 and 5 to 11.

  FIG. 1 is a block diagram showing the configuration of a system using a polarization control probe and an ultrasonic flaw detector according to this embodiment. FIG. 5 is an explanatory view of an ultrasonic flaw detector according to an embodiment of the present invention and a measurement form of defects or inclusions by a polarization control probe. 1 and 5, the same reference numerals indicate the same parts. However, the example shown in FIG. 5 does not limit the embodiment of the present invention.

  A phase difference 31, an amplitude 3 a, and an amplitude 3 b are input to the flaw detector 1 using the input unit 2. The waveform generator 32 provided in the waveform generator 3 generates a voltage waveform a and a voltage waveform b based on the phase difference, the amplitude a, and the amplitude b. The voltage waveform at this time may be a pulse wave or a burst wave. However, the pulse width and burst width are set appropriately according to the purpose. Moreover, the phase difference of the two-directional vibration component of the transverse wave ultrasonic wave can be specified by a time difference at each transmission timing, for example. Here, the input unit 2 inputs data to the flaw detection apparatus 1 by operating, for example, a keyboard of a personal computer, a slider displayed on the tablet, and a knob provided in the flaw detection apparatus 1.

  The voltage waveform a and the voltage waveform b are respectively applied to the first piezoelectric element 4a and the second piezoelectric element 4b provided in the polarization control probe, and are superposed on the inspection object 7 to generate ultrasonic waves. After that, the polarization control probe 4 receives an echo from the inspected object 7, and the received waveform a and the received waveform b are input to the waveform analysis unit 5 provided in the flaw detection apparatus 1. Here, the first piezoelectric element 4a or the second piezoelectric element 4b is, for example, PZT (lead zirconate titanate) or the like, and can convert an electric signal into vibration and conversely convert vibration into an electric signal. is there.

  Next, the operation procedure of the waveform analysis unit 5 of the present embodiment will be described using the flowcharts of FIGS. The waveform analysis unit includes a reception waveform transmission path 50 that captures two reception waveforms acquired by the polarization control probe, a calculator 52 that calculates the two reception waveforms, a memory 51, a comparator 53, and a waveform generation unit. 3 includes a control signal generator 54 that generates a phase 31 for transmitting a feedback signal, an amplitude 3a, and an amplitude 3b. The control signal generation unit 54 can be implemented by software on a personal computer, for example.

  First, the main axis direction in which the sound speed is maximized or minimized is measured using the waveform analysis unit 5. In this process, first, in step S101, the polarization control probe 4 is brought into contact with the device under test 7 with an appropriate weight. Next, in step S102, appropriate initial values are set for the amplitude 1 and the amplitude 2, and a position where a specific echo from the subject 7 occurs is input to the flaw detection apparatus 1 by the input unit 2. This echo is preferably the first bottom echo 101c in order to improve S / N. However, the second bottom echo 101e and subsequent multiple reflected echoes may be designated from the input unit 2 so that the amplitude can be easily compared in the subsequent steps.

  In step S103, the initial phase difference 31 is set to 0, and the waveform analysis unit 5 stores the combined amplitude of the received waveform a and the received waveform b in the memory 51. In step S104, the arithmetic unit 52 adds the reception waveform a and the reception waveform b weighted by the amplitude 3a and the amplitude 3b, respectively, and stores the amplitude of the composite waveform of the echo in the memory 51 in the comparator 53 in step S105. Compare with the value obtained. If the maximum value of the amplitude of the composite waveform of the echo is obtained, the process proceeds to step S107. If not, the process proceeds to step S106, and the second and subsequent steps are executed. In the second and subsequent steps, in step S106, the control signal generation unit 54 changes the ratio of the amplitude 3a and the amplitude 3b under the condition that the total amplitude is constant, and transmits the ratio to the waveform generation unit 3. Similarly, the comparison is repeated, and the ratio of the amplitude 3a and the amplitude 3b that maximizes the amplitude of the composite waveform of the echo is calculated. That is, by changing the ratio of the amplitude 3a and the amplitude 3b, it is possible to transmit a polarized wave whose vibration direction is controlled. The polarization here can be referred to as linear polarization. Θ calculated as Amplitude 3a / Amplitude 3b = tan θ is an angle formed by one shear vibration direction of the polarization control probe 4 and one of the principal axis directions of the inspection object 7. Further, the ratio of the amplitude 3a and the amplitude 3b that minimizes the combined echo amplitude, θ calculated as amplitude 3a / amplitude 3b = tan θ is one shear vibration direction of the polarization control probe 4 and the main axis of the object 7 to be inspected. The angle formed by the direction of 45 degrees. The control signal generation unit 54 transmits the measurement result in the main axis direction to the display device 6, and the display device 6 displays the measurement result. In addition, the to-be-inspected object in a present Example has shown the case where the anisotropic material with an angle of 90 degree | times is object.

  Here, when the amplitude of the composite waveform of the echo is the maximum value, the transmitted ultrasonic wave coincides with the principal axis direction of the material, so the ultrasonic wave becomes a single waveform. A waveform is received that is weakened by an amount that attenuates in the material. This is the largest echo received. However, when the transmission direction of the ultrasonic wave does not coincide with the main axis direction, the transmission waveform is separated into two polarized waves, and a phase difference is generated, so that a weakened composite waveform is received. By using this principle, the principal axis direction of the acoustic anisotropic material can be obtained.

Next, the initial phase difference is determined using the echo from the inspection object 7 used in the measurement in the principal axis direction. At this time, preferably, in step S107, the polarization control probe 4 is rotated, and the axis of the polarization control probe 4 and the main axis of the device under test 7 are made to coincide. In step S108, the amplitude 3a and the amplitude 3b are set to be equal, the phase difference 31 is set to 0, and the combined amplitude is stored in the memory 51. In step S109, ultrasonic waves are transmitted and received, and a composite echo amplitude is calculated. In step S110, the amplitude of the composite waveform of the echo is compared with the value stored in the memory 51 by the comparator 53. If the maximum value of the amplitude of the composite waveform of the echo is obtained, the process proceeds to step S112. If not, the process proceeds to step S111 and the second and subsequent steps are executed. In step S111, the phase difference 31 is sequentially changed, and step S109 is executed again. In step S110, the phase difference 31 that maximizes the amplitude of the composite waveform of the echo is obtained. The condition for maximizing the amplitude of the composite waveform of the echo is given by the following (Equation 1) when the axis of the polarization control probe 4 and the main axis of the inspection object 7 coincide.
v ₁ tv ₂ t = nλ + (φ / 2π) λ (Expression 1)
v ₁ and v ₂ are the sound speeds of the polarized waves in the directions of the two principal axes, and (φ / 2π) is the phase difference between the polarized waves, and is maximized when (Equation 1) is satisfied. Replacing each value in this equation yields (Equation 2).
ΔV / V ₀ ² = (n + φ / 2π) / fz (Expression 2)
Here, V ₀ is the average sound velocity of the polarized waves in the directions of the two principal axes, ΔV (= v ₁ −v ₂ ) is the difference in sound velocity of the polarized waves in the directions of the two principal axes, and f (= V ₀ / λ). Is the ultrasonic frequency, z is twice the distance from the inspection surface to the reflector producing the specific echo, φ is the initial phase, and n is the interference order. Although n is 0, other integer values may be used as necessary.

  As described above, since preparations for flaw detection are completed, flaw detection is started in step S112. Here, preparations are made in advance so that the interference is maximized on the bottom surface of the subject. However, this position may be appropriately changed depending on the measurement target.

  Describe flaw detection. When the phase difference 31 is changed from the amplitude 3a, the amplitude 3b, and the phase difference 31 set in the above procedure, the waveforms interfere with each other at the position where the condition of (Equation 2) is satisfied, and the signals are strengthened. When a reflector exists at this position, a combined waveform strengthened by interference is observed. It should be noted that echoes that are ambient noise interfere and weaken each other, so that the composite waveform becomes weak, and the strengthened composite waveform is displayed with emphasis. That is, since the position of z changes in (Expression 2), the waveform interferes and strengthens at this position on z, and weakens at other positions. By reducing the phase difference, when the interference position z moves inward from the bottom surface of the subject and there is a defect or inclusion at that position, the defect or inclusion can be captured more clearly. it can. The interference waveform is sent from the calculator 52 to the display 6 and displayed.

  As described above, the flaw detection focused on the designated position is possible.

  The polarization control probe 4 will be described with reference to FIG. The polarization control probe 4 has a structure in which a first piezoelectric element 4a and a second piezoelectric element 4b having different shear vibration directions of 90 degrees are laminated. Each piezoelectric element includes a first input / output transmission path 41a and a second input / output transmission path 41b for applying or reading a voltage waveform.

  Next, the waveform generation unit 3 will be described with reference to FIGS. FIG. 8 is a detailed configuration diagram of the waveform generator 32. The trigger 321 is input to the delay pulse generator, and generates two trigger pulses having a time difference in transmission timing by a designated phase difference. The arbitrary waveform generator 323a and the arbitrary waveform generator 323b generate the same waveform based on the input amplitude 3a and amplitude 3b, and the voltage waveform a and voltage are synchronized with the trigger pulse sent from the delay pulse generator, respectively. The waveform b is output. As a result, a voltage waveform having an arbitrary polarization state for controlling the polarization control probe can be generated. The voltage waveform a and the voltage waveform b are amplified as necessary via the amplifiers 321a and 321b, and transmitted from the first voltage waveform terminal 324a and the second voltage waveform terminal 324b, respectively.

  FIG. 9 shows the state of the polarization state generated by the polarization control probe 4. The polarization control probe 4 generates polarized waves that vibrate in two orthogonal axes, and displays the amplitude 3a, amplitude 3b, and phase difference 31 in the respective axial directions on the display 6 as polarization states. Such polarization is called elliptical polarization. This process is performed by the waveform analysis unit.

  The phase difference 31 is φ where the ratio of the axial length 3c and the axial length 3d of the displayed ellipse is tan (φ / 2). An arrow 3e indicates the rotation direction of the polarization, and is counterclockwise when 0 <φ <π and clockwise when π <φ <2π.

  Next, the waveform analysis unit 5 will be described with reference to FIGS. FIG. 10 shows an example of the received waveform of the designated echo. The reflected waves from the object to be inspected 7 are received by the first piezoelectric element 4a and the second piezoelectric element 4b, respectively, sent to the calculator 52 and calculated to generate a composite waveform.

  As shown in FIG. 10 (a), the received waveform 7a and the received waveform 7b of the ultrasonic wave that has passed through the test object having ultrasonic anisotropy change the phase difference 81, and the phase difference 81 is just an ultrasonic wave. The received waveform 7a and the combined waveform 7b of the received waveform 7b strengthen each other. On the other hand, as shown in FIG. 10B, when the phase difference 81 between the received waveform 8a and the received waveform 8b is exactly a half integer multiple, the combined waveform 8c of these received waveforms weakens. By controlling the initial phase difference 31, it is possible to control the ultrasonic path through which a combined waveform that causes constructive interference is obtained. The synthesized waveform is transmitted to the display 6 and displayed.

  FIG. 11 shows the detailed configuration of the computing unit 52. The received waveform is calculated by weighted addition 521. The composite waveform is calculated by weighting and adding the wave heights of the same reception time by the calculator 52. The weight 52a and the weight 52b can be calculated as the amplitude 3a and the amplitude 3b input to the waveform generator 3, respectively, so that the amount of change in the received polarization relative to the transmission polarization can be calculated. By using the value as a weight, a projection of the received waveform in an arbitrary direction can be obtained.

  Using the main axis direction, the polarization state, and the combined waveform displayed on the display device 6 in this way, the inspector can evaluate the minute reflector in the inspected object based on the difference from the healthy part. .

  Next, the ultrasonic flaw detection according to the second embodiment of the present invention will be described with reference to FIGS.

  FIG. 12 is a block diagram showing the overall configuration of an inspection apparatus according to Embodiment 2 of the present invention. In this embodiment, a polarization control probe using a first coil 14a, a second coil 14b and a permanent magnet 14c is used instead of the polarization control probe using the piezoelectric element shown in FIG. 1 in the first embodiment. It is what you do. In the inspection apparatus shown in FIG. 12, the description of the components having the same functions as those already described with reference to FIG. 1 is omitted.

  FIG. 13 is a perspective view showing the internal structure of a polarization control probe according to an embodiment of the present invention. An ultrasonic probe consisting of a permanent magnet and a single coil is commonly known as EMAT. In the present embodiment, the first coil 14a and the second coil 14b having a current direction different by 90 degrees are laminated immediately below the permanent magnet 14c so that polarization control is possible. Each coil includes an input / output transmission line 141a and an input / output terminal 141b for applying or reading a current waveform.

  By using the polarization control probe in the present embodiment, non-contact flaw detection that does not require a contact medium is possible. 12 to 13, the same reference numerals indicate the same parts. However, the example shown in FIG. 13 does not limit the embodiment of the present invention.

  Next, ultrasonic flaw detection according to Example 3 of the present invention will be described with reference to FIGS.

  FIG. 14 is a block diagram showing the overall configuration of an inspection apparatus according to Embodiment 3 of the present invention. FIG. 15 is an explanatory view of an ultrasonic flaw detector according to one embodiment of the present invention and a measurement mode of defects or inclusions by a polarization control probe. However, the example shown in FIG. 15 does not limit the embodiment of the present invention.

  This embodiment is a two-probe that uses the transmission polarization control probe 24 and the reception polarization control probe 34 in place of the polarization control probe 4 in FIG. Has a flaw detection function. FIG. 14 shows a block diagram using a polarization control probe using a piezoelectric element. However, instead of the polarization control probe using a piezoelectric element, the polarization control probe 14 using EMAT is used. Also good. In the inspection apparatus of FIG. 14, the description of the components having the same functions as those already described with reference to FIG. 1 is omitted.

  Next, the operation procedure of the waveform analysis unit 5 of the present embodiment will be described with reference to the flowchart of FIG.

  First, the direction of the main axis where the sound speed is maximum or minimum is measured. In this process, first, in step S201, the transmission polarization control probe 24 and the reception polarization control probe 34 are brought into contact with the device under test 7 with an appropriate weight. Next, in step S <b> 202, the position where a specific echo from the subject 7 occurs is input to the flaw detection apparatus 1 by the input unit 2. In order to improve the S / N, this echo is preferably the first bottom echo. However, the second and subsequent bottom echoes may be designated so that the amplitudes can be easily compared in subsequent steps.

  In step S203, the initial phase difference 31 is set to 0, and the amplitudes 3a and 3b are set to appropriate values. In the waveform analysis unit 5, the memory 51 stores the combined amplitude of the received waveform a and the received waveform b. In S204, the arithmetic unit 52 adds the received waveform a and the received waveform b with appropriate weights 52a and 52b, and adds the echo amplitude to the value stored in the memory 51 by the comparator 53 in step S205. Compare. When the maximum value of the amplitude of the composite waveform of the echo is obtained, the process proceeds to step S207. Otherwise, the process proceeds to step S206, and the second and subsequent steps are executed. In the second and subsequent steps, in step S206, the ratio of the amplitude 3a and the amplitude 3b is changed under the condition that the total amplitude is constant, and the ratio of the weight 52a and the weight 52b is changed under the condition that the total weight is constant. The comparison is repeated in the same manner as in the first step, and the ratio of the amplitude 3a and the amplitude 3b and the ratio of the weight 52a and the weight 52b are calculated by using an extreme value search algorithm such as a hill-climbing method. Θ calculated as amplitude 3a / amplitude 3b = tan θ is an angle formed by one shear vibration direction of the transmission polarization control probe 24 and one of the principal axis directions of the inspected object 7. Further, ψ where weight 52a / weight 52b = tan ψ is an angle formed by the reception polarization control probe 34 and one of the main axis directions of the device under test 7. The measurement result in the main axis direction is transmitted to the display 6 and displayed.

  Next, the initial phase difference is determined using the echo from the inspection object 7 used in the measurement in the principal axis direction. At this time, preferably, in step S207, the transmission polarization control probe 24 and the reception polarization control probe 34 are rotated so that the axes of the probes are aligned with the main axis of the device under test 7. Under the conditions of weight 52a = amplitude 3a and weight 52b = amplitude 3b, amplitude 3a and amplitude 3b that minimize the combined echo amplitude are set in step S208, the phase difference 31 is set to 0, and the combined amplitude is stored in the memory 51. Remember. In step S209, ultrasonic waves are transmitted and received, and a composite echo amplitude is calculated. If the maximum value of the amplitude of the composite waveform of the echo is obtained, the process proceeds to step S212. If not, the process proceeds to step S211 and the second and subsequent steps are executed. In step S211, the phase difference 31 is sequentially changed, and the phase difference 31 at which the amplitude of the composite waveform of the echo is maximized is measured. The condition that the amplitude of the composite waveform of the echo becomes maximum is given by (Equation 2) when the axes of the transmission polarization control probe 24 and the reception polarization control probe 34 coincide with the main axis of the device under test 7. However, z represents the path from the transmission polarization control probe 24 to the reception polarization control probe 34, and other symbols are the same as those described in the first embodiment. As described above, since preparations for flaw detection are completed, flaw detection is started in step S212.

  By using the configuration in the present embodiment, flaw detection by the two-probe transmission method can be performed.

  Next, ultrasonic flaw detection according to Example 4 of the present invention will be described with reference to FIGS.

  FIG. 17 is a block diagram showing the overall configuration of an inspection apparatus according to Embodiment 4 of the present invention. FIG. 18 is an explanatory diagram of a measurement mode of defects or inclusions by the ultrasonic flaw detector according to one embodiment of the present invention and the polarization control probe 4. However, the example shown in FIG. 18 does not limit the embodiment of the present invention. The present embodiment includes a scanning mechanism 9 that automatically scans the probe with respect to the inspection surface. The scanning mechanism 9 includes a position designator 91 that outputs a signal that designates the position of the probe, and a memory 92 that stores a waveform for each measurement position. The waveform received according to the position designator 91 is stored in the memory 92 together with the designated position. The stored waveform is sent to the display 16 and displayed. The display 16 has a function of displaying a two-dimensional flaw detection image based on the designated position and the waveform stored in the memory.

  As described above, a wide range of flaws can be detected at high speed, and the results are displayed by a method generally called a B scope or C scope, so that an inspector can easily find defects or inclusions.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the polarization control probe 4 may be composed of a piezoelectric element having a single vibration direction, and this piezoelectric element may be moved (rotated) in accordance with the direction in which it is desired to vibrate. In this case, since the probe can be constituted by a single piezoelectric element, the cost is reduced. The above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Flaw detector 2 ... Input part 3 ... Waveform production | generation part 3a, 3b ... Amplitude 4 ... Polarization control probe 4a ... 1st piezoelectric device 4b ... 2nd piezoelectric element 5 ... Waveform analysis part 6 ... Display device 7 ... Test object 7a, 7b, 8a, 8b ... received waveform 8c ... composite waveform 31 ... phase difference 32 ... waveform generator 51 ... memory 52 ... calculator 53 ... comparator 54 ... control signal generator

Claims (16)

A polarization control probe for generating a transverse wave ultrasonic wave having a first vibration direction and a transverse wave ultrasonic wave having a second vibration direction;
A waveform generator that controls the phase difference between the transverse wave ultrasonic wave having the first vibration direction and the transverse wave ultrasonic wave having the second vibration direction;
From the received waveform of the polarization control probe, a waveform analysis unit that calculates an interference waveform from a transverse wave ultrasonic wave having the first vibration direction and a transverse wave ultrasonic wave having the second vibration direction;
A display for displaying the interference waveform obtained by the waveform analyzer;
An ultrasonic inspection apparatus characterized by comprising: The ultrasonic inspection apparatus according to claim 1,
The waveform generator
A phase difference terminal for inputting an initial phase difference between a transverse wave ultrasonic wave having the first vibration direction and a transverse wave ultrasonic wave having the second vibration direction;
A first amplitude terminal for inputting an amplitude of a transverse wave ultrasonic wave having the first vibration direction;
A second amplitude terminal for inputting the amplitude of the transverse ultrasonic wave having the second vibration direction;
A first voltage waveform terminal that outputs a waveform generated based on the phase difference and the amplitude of the first transverse wave ultrasonic wave;
A second voltage waveform terminal that outputs a waveform generated based on the phase difference and the amplitude of the second transverse ultrasonic wave;
An ultrasonic inspection apparatus characterized by comprising: The ultrasonic inspection apparatus according to claim 2,
A display for displaying the anisotropic principal axis direction of the object to be obtained obtained from the combined amplitude of the transverse ultrasonic wave having the first vibration direction and the transverse ultrasonic wave having the second vibration direction obtained by the waveform analysis unit. When,
An ultrasonic inspection apparatus characterized by comprising: The ultrasonic inspection apparatus according to claim 1,
The waveform analysis unit calculates a polarization state of the ultrasonic wave at at least one depth in the inspection object,
A display for displaying the polarization state;
An ultrasonic inspection apparatus characterized by comprising: The ultrasonic inspection apparatus according to claim 1,
The waveform analysis unit
A reception waveform transmission line for capturing a reception waveform of the transverse wave ultrasonic wave having the first vibration direction and the transverse wave ultrasonic wave having the second vibration direction;
A computing unit for computing the two received waveforms;
A memory for holding a calculation result of the calculator;
A comparator for comparing the calculation result of the calculator and the amplitude held in the memory;
A control signal generator for generating a phase and amplitude to be transmitted to the waveform generator based on the result of the comparator;
An ultrasonic inspection apparatus characterized by comprising: The ultrasonic inspection apparatus according to claim 1,
The polarization control probe is
A first piezoelectric element that generates a transverse wave ultrasonic wave propagating perpendicularly to the inspection surface of the inspection object;
A second piezoelectric element that generates a transverse ultrasonic wave that is laminated on the first piezoelectric element and vibrates in a direction orthogonal to the vibration direction of the first piezoelectric element;
A first output terminal for output the voltage waveform to the first piezoelectric element,
A second output terminal for output the voltage waveform to the second piezoelectric element,
An ultrasonic inspection apparatus characterized by comprising: The ultrasonic inspection apparatus according to claim 1,
The polarization control probe is
A permanent magnet for applying a magnetic field perpendicular to the inspection surface at the surface layer of the inspection surface of the inspection object;
A first coil through which a current for generating an eddy current in a direction parallel to the inspection surface flows on a surface layer of the inspection surface;
A second coil through which a current that generates an eddy current flowing in a direction orthogonal to an eddy current generated by the first coil is parallel to the inspection surface on a surface layer of the inspection surface;
A first input terminal for inputting a current waveform to the first coil;
A second input terminal for inputting a current waveform to the second coil;
An ultrasonic inspection apparatus characterized by comprising: The ultrasonic inspection apparatus according to claim 1,
The polarization control probe includes a transmission polarization control probe and a reception polarization control probe for ultrasonic transmission / reception. The ultrasonic inspection apparatus according to claim 1,
A scanning mechanism for scanning the polarization control probe and a position designator for designating a position;
The ultrasonic display apparatus, wherein the indicator displays position information of the polarization control probe. A waveform generator for generating transverse wave ultrasonic waves having a first vibration direction and transverse wave ultrasonic waves having a second vibration direction;
A waveform generator that controls the phase difference between the transverse wave ultrasonic wave having the first vibration direction and the transverse wave ultrasonic wave having the second vibration direction;
A reception waveform transmission line for capturing a reception waveform of the transverse wave ultrasonic wave having the first vibration direction and the transverse wave ultrasonic wave having the second vibration direction;
A waveform analysis unit that calculates an interference waveform from the transverse wave ultrasonic wave having the first vibration direction and the transverse wave ultrasonic wave having the second vibration direction;
An ultrasonic flaw detector characterized by comprising: The ultrasonic flaw detector according to claim 10 ,
The waveform analysis unit obtains the anisotropic principal axis direction of the object to be inspected from the combined amplitude of the transverse wave ultrasonic wave having the first vibration direction and the transverse wave ultrasonic wave having the second vibration direction. Flaw detection equipment. The ultrasonic flaw detector according to claim 10 ,
The waveform analysis unit calculates a polarization state of ultrasonic waves at at least one depth in the object to be inspected. Transmits the polarized wave in which the phase difference between the transverse wave ultrasonic wave having the first vibration direction and the transverse wave ultrasonic wave having the second vibration direction is controlled into the inspected object,
Receiving the polarization echo that has passed through the inspected body;
Create an interferometric polarization echo from the received polarization echo,
The ultrasonic inspection method, wherein the interference polarization echo is displayed. The ultrasonic inspection method according to claim 13 ,
Compare the amplitude of the echo from the test object by changing the vibration direction of the transverse wave ultrasonic wave, and measure the main axis direction of the test object,
An ultrasonic inspection method characterized by displaying the main axis direction. The ultrasonic inspection method according to claim 13 ,
The first vibration in which the phase difference is controlled after fixing the respective transmission angles for transmitting the transverse wave ultrasonic wave having the first vibration direction and the transverse wave ultrasonic wave having the second vibration direction with respect to the principal axis direction. An ultrasonic inspection method comprising transmitting a transverse wave ultrasonic wave having a direction and a transverse wave ultrasonic wave having the second vibration direction into the object to be inspected. The ultrasonic inspection method according to claim 13 ,
Scan the ultrasonic wave transmission position on the flaw detection surface of the inspection object,
Conduct the inspection while recording the position information transmitted by the ultrasonic,
An ultrasonic inspection method comprising: synthesizing and displaying the interference polarization echo based on the position information.

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