JP2007085949A - Method and device for detecting texture change by ultrasonic wave - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for detecting a texture change by an ultrasonic wave, capable of detecting reliably and clearly, for example, the texture change in a welded part, and the texture change by heat treatment, surface modification or the like. <P>SOLUTION: The texture change is detected by transmitting the ultrasonic wave from a probe to a testing body and by receiving a back-scattered wave. A reference wave f1'(t) including the back-scattered wave is received in a reference part of the testing body. An inspecting wave g1(t) received in the inspection part of the testing body is normalized by dividing it with the reference wave f1'(t) or by finding a difference between the inspecting wave and the reference wave. The reference wave and the inspecting wave may be a function of a time and a frequency characteristic value other than a function of the time and an amplitude. Normalized display may serve as B-scope display of a cross section. The method/detector detects the texture change in the welded part, and the texture change by the heat treatment, the surface modification or the like. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tissue change detection method and detection apparatus using ultrasonic waves. More specifically, the present invention relates to a detection method and a detection apparatus for tissue change by ultrasonic waves that detect a tissue change by transmitting ultrasonic waves from a probe to a test body and receiving backscattered waves.

For example, the following are known as a detection method and a detection apparatus for tissue change by ultrasonic waves.
Tanaka Yasuaki et al., Development of non-destructive measurement technique of ultrasonic hardening depth, Toyota Technical Review, May 1998, Vol. 1, pages 94-99 Mihara, et al., Hardened layer depth evaluation by tissue scattering echo, sound field and material evaluation 3, published by the Nondestructive Inspection Association, 1994 Fall Meeting Summary, 1994, pages 315-322

All of these documents are intended to measure the quenching depth by scattering echo.
However, even if a metal structure change is detected by a backscattered wave, a clear signal cannot be detected because the signal is very small. In addition, when the probe, test arrangement, and material of the test specimen were changed, the analysis results differed and the reliability was insufficient.

  In view of such a conventional situation, the present invention is, for example, a method for detecting a tissue change by ultrasonic waves capable of clearly and reliably detecting a structure change such as a structure change, heat treatment, and surface modification of a welded portion. And it aims at providing a detection apparatus.

In order to achieve the above object, the feature of the tissue change detection method using ultrasonic waves according to the present invention is a method for detecting tissue changes by transmitting ultrasonic waves from a probe to a test body and receiving backscattered waves. Because
A reference wave including a backscattered wave is received at the reference part of the specimen, and the inspection wave received at the inspection part of the specimen is divided by the reference wave, or a reference is obtained by obtaining a difference between the inspection wave and the reference wave. It is to become.

  Usually, due to differences in probe convergence type and flat type, probe characteristics such as frequency, transducer diameter, attenuation, test placement such as distance between probe and test specimen, and differences in test specimen material The signal is buried in the base noise. However, by standardizing the test wave by dividing it by the reference wave, the influence of these base noises can be removed, and the reliability of the reception result can be improved and the signal can be clearly distinguished. Become. Instead of dividing the inspection wave by the reference wave, a difference between the inspection wave and the reference wave may be obtained. Whether to divide or obtain the difference may be selected depending on whether the base noise can be substantially removed.

  The reference wave and the inspection wave can use a function of time and amplitude, and can also use a function of time and a frequency characteristic value. For example, a first moment or the like can be used as the frequency characteristic value.

  The standardized display can be a B-scope display of a certain cross section. Further, by making the standardized display an average of a B-scope display of a certain cross section or a plurality of cross sections, it becomes possible to distinguish the display more clearly.

  The inspection section can detect a change in the structure of the weld. Moreover, the said test | inspection part may be heat-processed or surface-modified, and these depths can be detected.

As the test body, any material capable of generating a backscattered wave, such as ceramics, can be used in addition to a metal material.
Further, by using the oblique angle method, the influence of surface echo can be reduced, and the measurement result becomes clearer.

  On the other hand, the feature of the tissue change detection apparatus using ultrasound used in the method for detecting tissue change using ultrasound described in any of the above features is that the probe transmits ultrasonic waves to the specimen and receives backscattered waves. And receiving a reference wave including a backscattered wave at the reference portion of the specimen, and standardizing the inspection wave received by the inspection portion of the specimen by dividing the reference wave by the reference wave.

  As described above, according to the feature of the tissue change detection method and detection apparatus using ultrasonic waves according to the present invention, it is possible to eliminate the influence of base noise, and to clearly detect the tissue change with high reliability. It has become possible.

  Other objects, configurations, and effects of the present invention will become apparent from the following embodiments of the present invention.

Next, the present invention will be described in more detail with reference to the accompanying drawings as appropriate.
As shown in FIGS. 1 and 2, an ultrasonic tissue change detection apparatus 1 according to the present invention scans a test body 100 with a scanner driver 5, a scanner 6, and a probe 7 and processes an inspection result. 2, a pulsar receiver 4 that transmits and receives ultrasonic waves, and a monitor 3 that displays inspection results. In the case of the water immersion method, the test body 100 and the probe 7 are disposed in the water filled in the water tank 10. The test body 100 of the present embodiment is a steel material provided with a reference portion 110 and a welded portion 120. In the illustrated case, ultrasonic waves are transmitted and received from the probe 7 to the surface of the test body 100 vertically.

  FIG. 3 shows a received waveform, where (a) is an original waveform, (b) is a rectified waveform, and (c) is an envelope waveform that has been subjected to envelope processing. In both cases, a backscattered wave is confirmed between the surface echo and the bottom echo. The main object of the present invention is to remove the base noise of this backscattered wave. The backscattered wave amplitude is different from each other because the crystal grains are non-uniform and the metal structure is non-uniform, and it is difficult to standardize both amplitude waveforms. Therefore, by using the envelope detection waveform converted to the instantaneous amplitude (intensity), the parent portion and the welded portion are compared and standardized. The envelope processing is an envelope detection waveform estimated analytically using the Hilbert transform. The envelope detection may be directly converted using an analog circuit.

  FIG. 4 shows a schematic diagram of an envelope waveform expressed as a function of time and amplitude. FIG. 5 also shows a similar envelope waveform and shows the type of base noise Ec between the surface echo Ea and the bottom echo Eb1. FIG. 5A shows a case where a focusing probe is used, and the shape of the base noise Ec1 changes depending on the probe and test arrangement. FIG. 5B shows a case where a flat probe having a low frequency characteristic or a low attenuation coefficient is used. The base noise Ec2 has a gentle attenuation curve. FIG. 5C shows a case where a flat probe having a high frequency characteristic or a high attenuation coefficient is used. The base noise Ec3 has a steeper attenuation curve than the base noise Ec2. From these considerations, it is understood that the surface noise Ea and the bottom surface echo Eb1 are further added to the base noise, and in particular, the base noise excluding the influence of the bottom surface echo Eb1 becomes a curve obtained by short-circuiting the portion of the bottom surface echo Eb1.

  FIG. 4A shows the reference wave f1 (t), and the waveform of the reference wave f1 ′ (t) corrected by short-circuiting the bottom echo Eb1 portion expresses the base noise. . On the other hand, FIG. 4B shows the waveform of the inspection wave g1 (t). FIG. 4C shows a normalized waveform f2 (t) obtained by dividing the reference wave f1 (t) by the modified reference wave f1 ′ (t), and the normalized amplitude is 1 except for base noise. I can ask. Similarly, as shown in FIG. 4D, the influence of the base noise is obtained by dividing the inspection wave g1 (t) by the corrected reference wave f1 ′ (t) to obtain the normalized waveform g2 (t). It is the removed backscattered wave. In this way, the normalized backscattered wave Ed is clearly obtained. The normalized waveform g2 (t) may be obtained by obtaining the difference between the inspection wave g1 (t) and the corrected reference wave f1 ′ (t), which is substantially different from the form of superficial addition / subtraction / division / division. Division or subtraction may be performed.

  FIG. 6 shows a macrostructure and a microstructure of a cross section of the welded portion in the test body. Since the metal structure of the welded part is affected by heat at the time of welding, the metal structure (the size of crystal grains, the structure form, etc.) is not uniform up to the weld metal, the heat affected part (HAZ), and the base material. The result of FIG. 4 is based on scanning from the back surface of FIG. 6, and the normalized backscattered wave Ed corresponds to three areas of HAZ fine grain Ed1, HAZ coarse grain Ed2, and weld metal Ed3. It became clear that the tissue change can be detected by the fluctuation from the reference value 1 by the wave. In general, when the crystal grains are large, the back scattered wave tends to be large, and when the crystal grains are small, the back scattered wave tends to be small.

  Visualization is possible by performing line scanning and displaying a B-scan image. FIG. 7A is a B-scan image of a certain section, and FIG. 7B is a B-scan image obtained by averaging a plurality of signals of a certain section. In (b), B-scan scanning is performed on a plurality of cross-sections in a range where it is considered that there is no change in the welding state, and by performing spatial averaging of these data, data with further improved S / N is obtained, which is clear. .

Next, other embodiments of the present invention will be described. In addition, the same sign is attached | subjected to the member similar to the said embodiment.
8A and 8B are cross-sectional views showing variations of oblique flaw detection, where FIG. 8A shows a water immersion method, FIG. 8B shows a local water immersion method using a water bag 20, and FIG. 8C shows a position detected by an encoder 30. Possible direct contact methods, (d) respectively show a phased array method using a probe 7 capable of changing the incident angle. The same applies to oblique flaw detection in that a reference wave including a backscattered wave is received at the reference portion of the specimen and the inspection wave received at the inspection portion of the specimen is used.

  FIG. 9 is a diagram showing an example of the oblique flaw detection method, and FIG. 10 is a B-scan image of FIG. It will be understood that the use of the oblique angle probe makes it possible to detect the weld metal structure immediately below the irregularities such as extras.

  In order to image the portion immediately below the surplus portion of the welded portion 120, inspection may be performed from both sides of the welded portion 120 as shown in FIG. 11, or the refraction angle of the probe 7 may be increased as shown in FIG. When the test body 100 is a thin plate, ultrasonic waves may be reflected a plurality of times as shown in FIG. As shown in FIG. 14, it is also possible to detect a penetration defect portion 130 in butt welding. Furthermore, in order to carry out the vertical flaw detection method from the side of the extra portion, more accurate measurement is possible by processing the surface of the extra portion horizontally.

  In the said embodiment, the test body was limited to the metal material. However, the test body only needs to generate an ultrasonic backscattered wave, and the present invention can be used for, for example, measuring a change in structure of ceramics or the like. Moreover, it can be applied not only to the welded portion, but also to detection of heat treatment depth and surface modification depth.

  In the above embodiment, the influence of the base noise is removed by dividing the inspection wave g1 (t) by the corrected reference wave f1 '(t) to obtain the standardized waveform g2 (t). However, if the analysis of the bottom echo Eb1 is not performed, the normalized waveform g2 (t) may be obtained by dividing the inspection wave g1 (t) by the uncorrected reference wave f1 (t). The process of obtaining the corrected reference wave f1 '(t) by short-circuiting the reference wave f1 (t) at the bottom echo Eb1 and / or the surface echo as described above is referred to as a short-circuit process. In the present invention, the reference wave used for the standardization process may be short-circuited as necessary.

  In the above embodiment, a function of time and amplitude is used, but a function of time and frequency characteristic value can also be used. Here, the frequency characteristic value (shape parameter) means a value displayed by the following equations (1) to (6) in the frequency spectrum at each time. Expressions (1) to (4) are examples of typical frequency characteristic values ((1) is a primary moment). Equations (5) and (6) are the nth order moment (moment) around the origin and the nth order moment (moment) around the arithmetic mean, respectively.

  INDUSTRIAL APPLICABILITY The present invention can be used as a tissue change detection method and detection apparatus using ultrasonic waves. According to the present invention, it is possible to clearly detect a structural change such as a structural change of a welded portion, a heat treatment, and a surface modification with high reliability.

It is the schematic of the detection apparatus of the tissue change by the ultrasonic wave which concerns on this invention. It is a figure which shows the relationship between the cross section of the test body which is welding steel materials, and a probe. The waveform of a received wave is shown, (a) is an original waveform, (b) is a rectified waveform, and (c) is an envelope waveform subjected to envelope processing. FIG. 5 shows a schematic diagram of an envelope waveform expressed as a function of time and amplitude, where (a) shows the waveform of the reference wave f1 (t) and the corrected reference wave f1 ′ (t), and (b) shows the inspection wave g1 ( t), (c) is a normalized waveform f2 (t) obtained by dividing the reference wave f1 (t) by a modified reference wave f1 ′ (t), and (d) is a modified inspection wave g1 (t). The normalized waveform g2 (t) divided by the reference wave f1 ′ (t). It is a figure which shows the kind of base noise between the surface echo Ea and the bottom face echo Eb1. It is a figure which shows the cross section in the welding part of the steel materials which are welding test pieces, and the microscope picture of each site | part. (A) is a B-scan image of a certain section, and (b) is a B-scan image obtained by averaging a plurality of signals of a certain section. It is sectional drawing which shows the variation of oblique flaw detection, Comprising: (a) shows a water immersion method, (b) shows a local water immersion method, (c) shows a direct contact method, (d) shows a phased array method, respectively. It is a figure which shows an example of an oblique inspection method. 10 is a B-scan image of FIG. It is a figure which shows the other example of a path | route diagram of the bevel flaw detection method. It is a figure which shows the further another path | route diagram example of the bevel flaw detection method. It is a figure which shows the further another path | route diagram example of the bevel flaw detection method. It is a figure which shows the example of a detection of a penetration defect part. It is a figure which shows an example of the vertical flaw detection method.

Explanation of symbols

1: inspection device, 2: processing device, 3: monitor, 4: pulser receiver, 5: scanner driver, 6: scanner, 7: probe, 100: specimen, 110: reference part, 120: welded part (inspection) Part)

Claims (11)

A method for detecting a tissue change by ultrasonic waves in which a tissue change is detected by transmitting an ultrasonic wave from a probe to the test body and receiving a backscattered wave,
A reference wave including a backscattered wave is received at the reference part of the specimen, and the inspection wave received at the inspection part of the specimen is divided by the reference wave, or a reference is obtained by obtaining a difference between the inspection wave and the reference wave. A method for detecting a tissue change by ultrasonic waves, characterized by comprising: The method of detecting tissue change by ultrasonic waves according to claim 1, wherein the reference wave and the inspection wave are functions of time and amplitude. 2. The method for detecting a tissue change by ultrasonic waves according to claim 1, wherein the reference wave and the inspection wave are functions of time and a frequency characteristic value. The method for detecting a tissue change by ultrasonic waves according to any one of claims 1 to 3, wherein the normalized display is a B-scope display of a section. The method for detecting a tissue change by ultrasonic waves according to any one of claims 1 to 3, wherein the normalized display is an average of a B scope display of a cross section or a plurality of cross sections. The method for detecting a tissue change by ultrasonic waves according to claim 1, wherein the inspection part is a welded part. The method for detecting a tissue change by ultrasonic waves according to any one of claims 1 to 5, wherein the inspection section is heat-treated. The method for detecting a tissue change by ultrasonic waves according to any one of claims 1 to 5, wherein the inspection section is surface-modified. The method for detecting a tissue change by ultrasonic waves according to any one of claims 1 to 8, wherein the test body is a metal material. The method for detecting a tissue change by ultrasonic waves according to any one of claims 1 to 9, wherein an oblique angle method is used. 11. An apparatus for detecting tissue change using ultrasonic waves used in the method for detecting tissue change using ultrasonic waves according to claim 1, wherein the probe transmits ultrasonic waves to a specimen and receives backscattered waves. Set up a child,
A reference wave including a backscattered wave is received at the reference part of the test body, and the inspection wave received at the inspection part of the test body is normalized by dividing the reference wave by the reference wave. Detection device.

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