JPH1062395A - Ultrasoinc flaw detecting method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the S/N ratio of a received echo signal and perform a highly precise flaw detection to a concrete building by B scope image of high quality. SOLUTION: This device is constituted so as to have from a subject 10 to a personal computer 19, and the first to the m-th of N-pieces of reflected echo data obtained by changing the space of transmitting and receiving positions for emitting an ultrasonic wave to the subject 10 are added to form one data. Further, the second to the m+1-th of the data are added to form the next data, and m-pieces each are successively added while shifting one by one to form N-m+1 pieces of data in total, t-z transformation is performed to convert the reflected echo data in which amplitude is changed according to time into a data in which amplitude is changed according to distance, and these data are added together to form one reflected echo data. The addition number (m) is determined so that the multiplied value of the pitch for changing the space of transmitting and receiving positions of ultrasonic wave to the addition number (m) is the integer times the surface wave, so that the surface wave is canceled and reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting apparatus for performing nondestructive inspection of a test object, particularly a concrete structure having a complicated structure including an aggregate, using a pair of ultrasonic transducers having variable intervals. The present invention relates to a method and apparatus for flaw detection.

[0002]

2. Description of the Related Art Conventionally, in a nondestructive inspection of a concrete building of this type, an ultrasonic flaw detector using a pair of ultrasonic transducers with variable intervals has been used. FIG. 7 is a cross-sectional view illustrating a state of flaw detection by a conventional ultrasonic transducer, and FIG. 8 is a cross-sectional view illustrating a surface configuration of a concrete building of an inspection object. In FIG. 7, in this conventional example, a concrete building 1 as an object to be inspected is shown.
A pair of ultrasonic wave transducers 2a and 2b are arranged on the surface of. Contact catalysts 3a, 3b such as grease between the ultrasonic transducers 2a, 2b and the surface of the concrete building 1.
And pressed directly against this surface. Ultrasonic waves are radiated from one ultrasonic transducer 2a to the concrete building 1, and the radiated ultrasonic waves propagate in the concrete building 1 and are reflected at the defect portion 1a and the bottom surface 1b.

[0003] The reflected echo at the defective portion 1a and the bottom surface 1
The bottom echo reflected by b propagates to the surface of the concrete building 1, is received by the other ultrasonic transducer 2b, and receives an echo signal from the ultrasonic transducer 2b. The apparatus performs flaw detection measurement for the defective portion 1a. Thus, concrete building 1
In the flaw detection for, the radiated ultrasonic wave is not incident if an air layer exists between the ultrasonic wave transducers 2a and 2b and the surface of the concrete building 1, so that the couplant 3 such as grease is used.
a, 3b are applied. The thinner the couplants 3a and 3b, the more easily the ultrasonic waves from the ultrasonic transducers 2a and 2b are transmitted. In other words, the receiving sensitivity of the ultrasonic transducer 2b increases.

Therefore, it is ideal that the couplants 3a and 3b are applied uniformly and thinly. However, as shown in FIG. 8, the couplants 3a and 3b are actually rough and uneven, as shown in FIG. The thicknesses of 3a and 3b become non-uniform, and the area between the ultrasonic radiation surfaces of the ultrasonic transducers 2a and 2b and the surface of the concrete building 1 deteriorates. For this reason, the thickness of the couplants 3a and 3b is not uniform, so that the receiving sensitivity of the ultrasonic transducer 2b fluctuates, and the sensitivity generally tends to be low.

Further, the concrete building 1 has a complicated structure including aggregates such as stones, and radiated ultrasonic waves propagating in the inside, reflection echoes and bottom echoes due to the defective portion 1a are scattered, and the attenuation is increased. . For this reason, a relatively low frequency ultrasonic wave having a wavelength sufficiently longer than the width of the aggregate is emitted to reduce scattering attenuation. The size of the ultrasonic transducers 2a and 2b used in this case is approximately the same as the wavelength of the ultrasonic wave, and the surface wave shown in FIG. 7 is easily generated. In 2b, it is received together with the bottom surface echo.

FIG. 9 is a waveform diagram showing a surface wave and a bottom echo received by the ultrasonic transducer 2b. In FIG. 9, the received echo signal received by the ultrasonic transducer 2b has a waveform when no defect echo exists.
The surface wave in the received echo signal is unnecessary for observation of flaw detection measurement. In particular, when the thickness of the concrete building 1 to be inspected is small, the surface wave is superimposed, the waveform rise of the bottom surface echo becomes unclear, and high-precision flaw detection measurement cannot be performed.

[0009] In FIG. 9, the surface wave and the bottom echo are partially overlapped, and it is difficult to clearly identify the rise of the bottom echo. Further, when the reflected echo from the defective portion 1a is superimposed on the surface wave and the bottom echo, the spectrum of the received echo signal is complicated. This is because the frequency of the radiated ultrasonic wave is low and the concrete building 1
This is an essential problem when the thickness of the thin film is small. That is, the attenuation in the member is small, and the noise / signal (S / N) ratio of the reception echo signal output from the ultrasonic transducer 2b is deteriorated by the high-intensity bottom echo.

[0008]

As described above, in the above conventional example, the surface wave is superimposed on the bottom echo and the reflection echo from the defective portion, and the S / N ratio of the reception echo signal output from the ultrasonic transducer 2b is increased. The ratio tends to deteriorate. Further, in particular, there is a drawback that the level of surface noise, which is unnecessary noise, is high, and as a result, highly accurate flaw detection measurement cannot be performed.

SUMMARY OF THE INVENTION The present invention solves such problems in the prior art, and improves the S / N ratio of a received echo signal. In particular, a surface which is unnecessary noise in a flaw detection measurement of a concrete building. Provided is an ultrasonic flaw detection method and apparatus capable of performing high-precision flaw detection measurement using a high-quality B-scope image with a reduced wave level.

[0010]

In order to achieve this object, the present invention changes the interval between the transmitting and receiving positions of ultrasonic waves,
This is an ultrasonic flaw detection method for detecting flaws in an inspected object by irradiating the inspected object and receiving reflected echoes of reflected ultrasonic waves, and changing the interval between ultrasonic wave transmitting and receiving positions to obtain N reflections. In addition to obtaining the echo data, the first m-th reflected echo data is added to create one data, and then the second to the (m + 1) th data is added to create the next data. Further, by sequentially shifting every one data and adding m data, a total of N-m + 1 data is generated, and a tz conversion is performed on the N-m + 1 data. The reflected echo data whose amplitude has changed with time is converted into data whose amplitude changes with distance,
One reflection echo data is generated by adding Nm + 1 data obtained by performing the tz conversion.

Further, the ultrasonic flaw detector according to the present invention comprises a pair of ultrasonic transducers that move independently, a moving mechanism that varies the distance between the ultrasonic transducers, and the distance between the ultrasonic transducers. A relative interval measuring unit for measuring, an ultrasonic signal transmitting unit for transmitting an ultrasonic signal for radiating the ultrasonic wave from one of the ultrasonic transducers to the object to be inspected, and an arithmetic unit; A storage unit for storing the reflected echo data received by the other of the sound wave transducers, and adding up to the first m-th of the N reflected echo data read from the storage unit to create one data,
Next, the next data is created by adding the (m + 1) -th data from the second, and further, data is added by shifting the data one by one and added by m each, so that a total of N-m + 1 data Is created, and tz is applied to the N-m + 1 pieces of data.
By performing the conversion, the reflected echo data whose amplitude has changed with time is converted into data whose amplitude changes with distance, and one piece of reflected echo data obtained by adding the tz-converted N-m + 1 data is obtained. Has been generated.

Further, in the ultrasonic flaw detection method or apparatus according to the present invention, the above-mentioned tz conversion is performed by √ (L1 ² + Z ² ) + (√L2 ² + Z ² ) = Ct. Here, L1: the distance between the scanning line position and one of the ultrasonic transmission / reception waves, L2: the distance between the scanning line position and the other of the ultrasonic transmission / reception waves, Z: the assumed depth of the reflection source, C: the inspection target The speed of sound of an ultrasonic wave propagating through the body, t: a time parameter of a reflected echo whose amplitude changes with time.

Further, in the ultrasonic flaw detection method or apparatus according to the present invention, the above-mentioned tz conversion is performed by {L ² + (2Z) ² } = Ct. Here, L: interval between ultrasonic transmission / reception waves, Z: assumed depth of the reflection source, C: sound velocity of the ultrasonic wave propagating through the test object, t: time parameter of a reflected echo whose amplitude changes with time. is there.

Further, in the ultrasonic flaw detection method or apparatus according to the present invention, the multiplication value of the pitch for changing the interval between the ultrasonic wave transmitting and receiving positions and the addition number m is an integral multiple of the surface wave. m is determined. Further, in the ultrasonic flaw detection method or apparatus according to the present invention, the respective positions of the pair of ultrasonic transducers are equally moved from the scanning line position to obtain N data, and at the same time, tz conversion is performed to obtain the symmetry. Is generated.

Further, the ultrasonic flaw detector according to the present invention, in the above configuration, includes a display processing section for performing processing for displaying a single piece of reflected echo data calculated and generated by the calculation section on a screen, and a display processing section. And a screen display for displaying a display signal from the PC on a screen. Further, the ultrasonic flaw detector of the present invention,
This ultrasonic flaw detector is mounted on a carriage that can move on the inspection object.

The ultrasonic flaw detection method and apparatus of the present invention vary the distance between a pair of ultrasonic transducers to radiate ultrasonic waves to an object to be inspected and to reflect reflected ultrasonic waves. Is received, and N pieces of reflected echo data are obtained.
One data is created by adding up to the first m-th reflection echo data. Further, the next data is created by adding the (m + 1) th data from the second data, and
Create data that is shifted m by m and added by m
A total of N-m + 1 pieces of data are created, and tz conversion is performed to convert reflected echo data whose amplitude changes with time into data whose amplitude changes with distance. This t
N-m + 1 pieces of -z-converted data are added to generate one piece of reflected echo data.

In this case, the waveform phases when the reflection source is truly located at the position of the scanning line become substantially equal, and the amplitude is added and emphasized. If the reflection source is shifted from the position of the scanning line, a phase shift occurs. The result of this addition becomes smaller due to the cancellation of the amplitude. That is, the S / N ratio of the received echo signal is improved. Further, in the ultrasonic flaw detection method and apparatus of the present invention, the addition number m is determined so that the multiplication value of the pitch for changing the interval between the ultrasonic wave transmission and reception positions and the addition number m is an integral multiple of the surface wave. ing. Therefore, the surface wave is
The negative phase waveform cancels out and is attenuated, and the bottom echo is emphasized because there is no negative phase waveform.

Further, in the ultrasonic flaw detection method and apparatus according to the present invention, the respective positions of the pair of ultrasonic transducers are equally moved to obtain N data, and the tz conversion is performed by √ ｛L ² + (2Z) ² ｝ = Ct. As a result, a B-scope image having symmetry that facilitates flaw detection analysis is generated.

As described above, according to the present invention, a noise-to-signal (S / N) ratio of a received echo signal is improved, and in particular, a surface wave is offset and reduced, and a B-scope image having symmetry is generated. By doing so, even in the measurement of concrete buildings that were considered difficult to detect with high precision,
High-precision flaw detection measurement becomes possible.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the ultrasonic flaw detection method and apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment of the ultrasonic flaw detector of the present invention. In FIG. 1, this ultrasonic flaw detector includes a moving mechanism 11 on which tires 11b, 11c and the like rotate and move on the surface of a test object 10 such as concrete.
Ultrasonic transducers 12a, 12 placed in contact with each other through
2b. The ultrasonic transducers 12a and 12b may be configured to directly contact the surface of the test object 10 and move without providing the tires 11b and 11c.

An ultrasonic transducer 12 is provided in the moving mechanism 11.
A slide mechanism 11a for moving a in parallel with the surface of the test object 10 and a stepping motor 11d for driving the slide mechanism 11a are provided. The ultrasonic pulse signal generated by the pulse generator 14 under the control of the system controller 13 is supplied to the ultrasonic transducer 12a after being amplified by the amplifier 15.

An ultrasonic pulse radiated from the ultrasonic transducer 12a to the device under test 10 propagates through the member and is reflected at a defective portion or a bottom surface. The wave is received by the device 12b. Here, the electrical converted reception echo signal is amplified by the amplifier 16 and input to the A / D converter 17, quantized and sampled, and input to the system control unit 13. The received echo data converted into a digital signal by the
3a, and the measurement control unit 13b controls the generation of the ultrasonic pulse signal by the pulse generator 14. Further, the movement control unit 13c controls the rotation of the stepping motor 11d.

The system control unit 13 is connected to the personal computer 19 through an interface such as RS232C. The personal computer 19 includes a display 19a such as a cathode ray tube, a printer 19b, and an operation unit 1.
9c is connected. This personal computer 1
Numeral 9 is for performing flaw detection analysis from a B scope image generated from the received echo data stored in the waveform storage device 13a.

The personal computer 19 includes a main control section 21a for controlling each section, an arithmetic section 21b for performing an arithmetic operation for analysis, display on a display 19a and a printer 19b,
A display signal processing unit 21c for outputting a print signal; and a main control unit 21 which fetches an input operation signal from the operation unit 19c.
The input signal processing unit 21d sends the signal to the input signal processing unit 21a.
Next, the operation in the configuration of the first embodiment will be described.

When an operation instruction for flaw detection measurement is performed on the operation unit 19c, the operation instruction signal is transmitted to the personal computer 1
9 is taken in by the main control section 21a through the input signal processing section 21d, and the sequence control of the flaw detection measurement is started.
First, the main control unit 21a controls transmission to the measurement control unit 13b in the system control unit 13, and the measurement control unit 13b
, The pulse generator 14 generates an ultrasonic pulse signal, amplifies it with the amplifier 15, and sends it to the ultrasonic transducer 12a. The ultrasonic transducer 12a emits an ultrasonic pulse to the device under test 10, and the reflected echo or surface wave is received by the ultrasonic transducer 12b.

The main controller 21a in the personal computer 19 is connected to the movement controller 1 in the system controller 13.
3c is controlled. The movement control unit 13c controls the stepping motor 11d of the movement mechanism unit 11, and the slide mechanism 11a is driven by the step rotation under the control, and the ultrasonic transducer 12a is finely stepped, and the ultrasonic transducer 12b is moved. Is varied.

Along with the change of the interval L, the surface wave on the device under test 10 received by the ultrasonic transducer 12b is converted into an electric signal, and the received signal is amplified by the amplifier 16 to be converted into an A / D converter 17 To enter. Here, the signal is converted into a digital signal and stored in the waveform storage device 13a in the system control unit 13. After this storage, the personal computer 19 captures the received echo data stored in the waveform storage device 13a, and performs mutual processing of the received echo data by arithmetic processing with the arithmetic unit 21b and performs processing such as tz conversion. Final A
A scope waveform and a signal of a B scope image are generated. This image signal is displayed on the display unit 19a through the display signal processing unit 21c.
And displays it on the screen here. Further, printing is performed by the printer 19b as necessary, and the recording paper is output.

Hereinafter, the flaw detection measurement will be described in detail. FIG. 2 is a diagram for explaining a variable state and an ultrasonic propagation state of the ultrasonic transducers 12a and 12b in the flaw detection measurement of the first embodiment. FIG. 3 shows a data processing state in the flaw detection measurement. It is a figure for explaining. FIG.
In FIG. 3 and FIG.
The d rotates stepwise to drive the slide mechanism 11a, and the ultrasonic transducer 12a moves. This ultrasonic transducer 1
For each step movement position 2a, the received echo signal is processed, and data processing for obtaining one scan line data for generating a B scope image is performed. In order to obtain this one scan line data, the N received echo data is stored in the waveform storage device 13 at each step movement position N of the ultrasonic transducer 12a.
Remember with a.

As shown in FIG. 3, the received echo data stored in the waveform storage device 13a is first converted from the N pieces of reflected echo data by the control and arithmetic processing of the main control section 21a and the arithmetic section 21b in the personal computer 19, as shown in FIG. Is created by adding up to m pieces of data.
Next, the (m + 1) th data from the second data is added to create the next data, and data is added by shifting the data one by one in order in order to create m data. In this process, a total of N−m + 1 data is created. Create data for This treatment reduces surface waves.

Hereinafter, the reduction of the surface wave will be described. FIG. 4 is a diagram for explaining reduction of surface waves.
FIG. 5 is a waveform diagram showing a received echo when the surface wave is reduced. In FIG. 4, the ultrasonic transducer 12a is finely moved in steps, the ultrasonic transducer 12b is fixed, and the ultrasonic transducers 12a and 12b are sequentially changed so as to be separated. In this case, the ultrasonic transducer 12
In a and 12b, since the interval at which the reflected echo propagates is longer than the interval at which the surface wave propagates, the surface wave is received at a time earlier than the reflected echo.

The surface wave and the reflected echo are received by the ultrasonic wave transmitter / receiver 12b in accordance with the step movement of the ultrasonic wave transmitter / receiver 12a, and the surface waves are shown in FIGS. 5A, 5B, 5C, and 5D. )
As shown in the figure, every time the interval between the ultrasonic transducers 12a and 12b is increased, the delay from the first reception time t1 of the surface wave is caused. The reflected echoes are shown in FIGS.
(C) As shown in (d), from the first reception time t2,
Very little delay. In particular, when the test object 10 is thick, the delay from the reception time t2 is so small that the delay cannot be determined.

Therefore, FIGS. 5 (a), 5 (b), and 5 (c)
When the received echo data shown in (d) is added, FIG.
As shown in (e), the surface wave is attenuated by canceling the opposite phase waveform. In addition, the bottom surface echo is emphasized because there is no reverse phase waveform. Note that the ultrasonic transducer 12
When the addition number m is determined such that the total movement amount of the ultrasonic transducer 12a becomes an integral multiple of the wavelength of the surface wave, the multiplication value of the step movement interval between the a and 12b and the addition number m, Since the opposite-phase waveforms whose axes match each other cancel each other, the surface wave is extremely reduced. In this case, the S / N ratio of the received echo signal is further improved.

Further, creation of one scan line data based on FIG. 2 will be described. In FIG. 2, in order to obtain scanning line data, first, by performing tz conversion on all of the created N-m + 1 data, reflected echo data whose amplitude has fluctuated with time can be obtained by distance measurement. Is also converted into data whose amplitude varies. This tz conversion is performed by the following equation (1).

√ (L1 ² + Z ² ) + √ (L2 ² + Z ² ) = Ct (1) L1: Distance between scanning line position and one of ultrasonic transducers 12a, 12b L2: Scanning line position and super Distance between the other one of the sound wave transducers 12a and 12b Z: assumed depth of the reflection source C: sound speed of the ultrasonic wave propagating through the test object 10 t: time parameter of the reflected echo whose amplitude changes with time The received echo shown in (a) of FIG. 2 by the tz conversion is generated in the waveform after the tz conversion shown in (b). This is represented assuming that the reflection sources of the received echo shown in (a) all exist on the positions of the scanning lines and are converted into distance axis data, so that the positions of the reflection sources are linear. Will be found out.

This tz conversion is performed on all N-m + 1 data, and as a result of adding these data, the waveform phase when the reflection source is truly located at the position of the scanning line becomes substantially equal. The amplitudes are added and emphasized. On the other hand, if the position of the reflection source is shifted from the position of the scanning line, a phase shift occurs, and as a result of the addition, the amplitude is canceled out and becomes smaller. Therefore, the S / N ratio of the received echo signal is improved,
Flaw detection analysis is easily performed from a high-quality B-scope image displayed on the screen of the display 19a.

Next, a second embodiment will be described. In the second embodiment, t is expressed by the following equation (2) with respect to (Equation 1).
-Z conversion is performed. {L ² + (2Z) ² } = Ct (2) L: distance between a pair of ultrasonic transducers 12a and 12b Z: assumed depth of reflection source (bottom surface) C: test object The sound velocity of the ultrasonic wave propagating through t: the time parameter of the reflected echo whose amplitude changes with time. The tz transform of the second embodiment is based on the assumption that the reflection source is a bottom echo or a horizontal defect, such as a separation. This is effective when assuming the case, and is mainly used when obtaining the plate thickness.
Further, it is effective to use the present invention also when obtaining the propagation speed of the ultrasonic wave propagating inside the test object 10.

Next, a third embodiment will be described. FIG. 6 is a diagram for explaining the third embodiment. 6, in the third embodiment, the ultrasonic transducers 12a, 12a,
Both of them are separated from each other at an equal step movement interval with respect to the scanning line position. In this case, the moving mechanism 11 shown in FIG. 1 is also arranged on the ultrasonic transducer 12b and driven by the stepping motor 11d, and the moving direction of the moving mechanism 11 is opposite to that of the ultrasonic transducer 12a. It may be configured as follows.

As shown in FIG. 6, both ultrasonic transducers 12a and 12b are moved away from or closer to the scanning line position at equal step movement intervals La and Lb. The process of obtaining the N data is performed for each movement. In this case, the tz transform uses (Equation 2) in the second embodiment. As a result, the B scope image is always targeted, and the image analysis of the flaw detection measurement becomes easier.

[0039]

As is apparent from the above description, according to the ultrasonic flaw detection method and apparatus of the present invention, N pieces of reflected echo data obtained by changing the interval between a pair of ultrasonic transducers are obtained. One data is created by adding up to the first m-th data. Further, the (m + 1) th data from the second data is added,
Data is sequentially shifted one by one and m data is added to create N-m + 1 data in total, and tz conversion is performed.

That is, the reflected echo data whose amplitude changes with time is converted into data whose amplitude changes with distance. The tm-converted N-m + 1 pieces of data are added to generate one piece of reflected echo data. Therefore, depending on the positions of the reflection source and the scanning line, the amplitudes are added and emphasized, and the amplitudes are canceled out to be small, so that the S / N ratio of the received echo signal is improved, and it is difficult to perform high-accuracy flaw detection. It will be possible to perform high-precision flaw detection measurement even in the measurement of concrete buildings that have been done.

Further, in the ultrasonic flaw detection method and apparatus of the present invention, the multiplication value of the pitch for changing the interval between the ultrasonic wave transmitting and receiving positions and the addition number m is an integral multiple of the surface wave so that the addition number m Is determined, the surface wave cancels and attenuates the opposite-phase waveform. Also in this case, highly accurate flaw detection measurement can be performed on a concrete building. Furthermore, in the ultrasonic flaw detection method and apparatus of the present invention, the position of each of the pair of ultrasonic transducers is moved equally to obtain N data, and the tz conversion is performed. A B-scope image having a symmetry that facilitates the inspection is generated, and high-precision flaw detection measurement can be performed on a concrete building.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of an ultrasonic flaw detector according to the present invention.

FIG. 2 is a diagram for explaining a variable state and an ultrasonic propagation state of the ultrasonic transducer in the flaw detection measurement of the first embodiment.

FIG. 3 is a diagram for explaining a data processing state in flaw detection measurement according to the first embodiment;

FIG. 4 is a diagram for explaining reduction of a surface wave in the first embodiment.

FIG. 5 is a waveform diagram showing a reception echo when the surface wave is reduced in the first embodiment.

FIG. 6 is a diagram for explaining a third embodiment;

FIG. 7 is a cross-sectional view for explaining a state of flaw detection by an ultrasonic transducer in a conventional example.

FIG. 8 is a cross-sectional view for explaining a surface configuration of a concrete structure of an inspection object in a conventional example.

FIG. 9 is a waveform diagram showing a surface wave and a bottom surface echo in a conventional example.

[Explanation of symbols]

 10: Inspection object 11: Moving mechanism unit 11a: Slide mechanism 11b: Stepping motor 12a, 12b: Ultrasonic transducer 13: System control unit 13a: Waveform storage device 13b: Measurement control unit 13c: Movement control unit 14: Pulse Generators 15 and 16: Amplifier 17: A / D converter 19: Personal computer 19a: Display 19b: Printer 19c: Operation unit 21a: Main control unit 21b: Operation unit 21c: Display signal processing unit 21d: Input signal processing unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Noriko Nomura 2-16-46 Minami Kamata, Ota-ku, Tokyo Inside Tokimec Co., Ltd.

Claims (8)

[Claims] 1. The method according to claim 1, wherein the interval between the transmitting and receiving positions of the ultrasonic waves is changed,
In an ultrasonic flaw detection method for detecting a flaw of an inspected object by receiving a reflected echo of an ultrasonic wave radiated and reflected by the inspected object, the number of ultrasonic waves transmitted and received is changed by changing an interval between ultrasonic waves. , And add up to the first m-th reflection echo data to create one data.
The next data is created by adding the (m + 1) th data from the (m) th data, and further, the data is sequentially shifted by one and m data is added, thereby creating a total of N−m + 1 data, The tz conversion is performed on the N-m + 1 pieces of data, and the reflected echo data whose amplitude has changed with time is converted into data whose amplitude changes with distance. An ultrasonic flaw detection method characterized by generating one reflection echo data by adding -m + 1 data. 2. A pair of ultrasonic transducers that move independently, a moving mechanism that varies an interval between the ultrasonic transducers, and a relative interval measuring unit that measures an interval between the ultrasonic transducers. An ultrasonic signal transmitting unit that transmits an ultrasonic signal for radiating an ultrasonic wave from one of the ultrasonic transducers to an object to be inspected; and a storage unit that stores reflected echo data received by the other of the ultrasonic transducers. And the first m pieces of the N pieces of reflected echo data read out from the storage unit are added to create one data, and then the second to the (m + 1) th data are added to obtain the next The data is created, and data is further created by adding m data by shifting the data one by one, and a total of Nm + 1 data is created. The tz conversion is performed on the Nm + 1 data. And the reflection eco was changed in amplitude with time. An arithmetic unit that converts data into data whose amplitude changes with distance, and generates one piece of reflected echo data by adding Nm + 1 data obtained by performing the tz conversion. Flaw detector. 3. The ultrasonic flaw detection method or apparatus according to claim 1 or 2, wherein the tz conversion is performed as follows: √ (L1 ² + Z ² ) + √ (L2 ² + Z ² ) = Ct L1: Scanning line L2: Distance between the scanning line position and the other of the ultrasonic wave transmission and reception Z: Depth of assumed reflection source C: Sound velocity of ultrasonic wave propagating through the inspection object t An ultrasonic flaw detection method or apparatus, which is performed using a time parameter of a reflected echo whose amplitude changes with time. 4. The ultrasonic flaw detection method or apparatus according to claim 1 or 2, wherein the tz conversion is performed by: {L ² + (2Z) ² } = Ct L: interval Z between ultrasonic transmission and reception waves. : Depth of assumed reflection source C: Sound velocity of ultrasonic wave propagating through the inspected object t: Ultrasonic flaw detection method or apparatus characterized by performing with a time parameter of a reflected echo whose amplitude changes with time. 5. The ultrasonic flaw detection method or apparatus according to claim 1, wherein the multiplication value of the pitch for changing the interval between the transmitting and receiving positions of the ultrasonic wave and the addition number m is an integer of the surface wave. An ultrasonic flaw detection method or apparatus, wherein the addition number m is determined so as to be doubled. 6. An ultrasonic flaw detection method or apparatus according to claim 1 or 2, wherein the respective positions of the pair of ultrasonic transducers are moved equally from the scanning line position to obtain N data. , Ts conversion, and generating a B-scope image having symmetry, an ultrasonic inspection method or apparatus. 7. The ultrasonic flaw detector according to claim 2, further comprising: a display processing unit that performs processing for displaying a single piece of reflected echo data calculated and generated by the calculation unit on a screen; and the display processing unit. An ultrasonic flaw detector comprising: a screen display for displaying the display signal of the above on a screen. 8. An ultrasonic flaw detector, wherein the ultrasonic flaw detector according to claim 2 is mounted on a carriage movable on an object to be inspected.