JP2001013114A - Ultrasonic inspection method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic inspection method and a device capable of detecting, easily and highly accurately, the position of a defect in the plate surface direction and the position thereof in the plate thickness direction. SOLUTION: This device has a reflected-echo detecting means 10 for irradiating an ultrasonic wave into a test object 2 and for detecting reflected echo of the ultrasonic wave reflected by a discontinuous part of the test object 2, and a diffracted-wave detecting means 11 for irradiating an ultrasonic wave into the test object 2 and for detecting the ultrasonic wave diffracted by the discontinuous part. And, the reflected-echo detecting means 10 and the diffracted- wave detecting means 11 are composed integrally and moved simultaneously along the same inspection part 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic inspection method and apparatus suitable for inspecting defects in welds such as pipes.

[0002]

2. Description of the Related Art Conventionally, for example, inspection of a welded portion of a pipe has often been performed by an X-ray transmission test. X-ray transmission tests are based on the relationship between the test results and the strength of the weld, and have a proven track record of assuring the safety of structures over a long period of time. Because of its recordability, it was frequently used for inspection of welds.

[0003] On the other hand, ultrasonic inspection has been regarded as a voluntary inspection performed by a business operator as necessary in the inspection of welded parts, but recently, a manual or automatic probe has been provided. Ultrasonic flaw detectors have been developed and many practical examples have been introduced. Furthermore, some of these ultrasonic flaw detectors can record inspection results.

[0004]

However, in the conventional ultrasonic flaw detector, it was difficult to accurately detect the position of the defect in the thickness direction. This is because the ultrasonic flaw detection method uses ultrasonic waves having a spread. If the position of the defect in the thickness direction can be accurately detected, more advanced welding design can be expected by feeding back to the design of the welded portion.

Therefore, as a method of detecting the position of a defect in the thickness direction, TOFD (Timeof Flight) is used.
Difference) method has been developed. This T
In the OFD method, when an ultrasonic wave is radiated to a weld or the like, if there is a discontinuous portion such as a defect, the ultrasonic wave is diffracted at the discontinuous portion. However, the position of the discontinuous portion is detected by calculating the time difference from the ultrasonic wave that has passed linearly, and the position of the discontinuous portion in the thickness direction can be accurately detected.
However, in the TOFD method, a defect detection state is not high in a qualitative inspection method, and there is a problem in applying only this method. Also, the screen was difficult to see, and it was difficult to identify the defect.

An object of the present invention is to solve such problems, and it is possible to easily and accurately detect the position of a defect in the plate surface direction and the position of the defect in the plate thickness direction.
It is another object of the present invention to provide an ultrasonic inspection method and apparatus capable of easily determining a result.

[0007]

SUMMARY OF THE INVENTION The present invention is an ultrasonic inspection method, and is configured as follows to solve the above-mentioned technical problems. That is, the ultrasonic inspection method of the present invention comprises: a reflection echo detecting step of irradiating an ultrasonic wave to an inspection object and detecting a reflection echo of the ultrasonic wave reflected at a discontinuous portion of the inspection object; And a diffracted wave detecting step of detecting a diffracted wave from the discontinuous portion of the inspection object by irradiating an ultrasonic wave to the object, wherein the reflected echo detecting step and the diffracted wave detecting step are performed simultaneously. And

Further, the probe in the reflection echo detection step and the probe in the diffraction wave detection step are integrally moved, and the reflection echo detection step and the diffraction wave detection step have the same defect. It is characterized in that an image for detection is created.

Further, the ultrasonic inspection apparatus according to the present invention is characterized in that reflected ultrasonic wave detecting means for irradiating an ultrasonic wave to an inspection object and detecting a reflection echo of the ultrasonic wave reflected at a discontinuous portion of the inspection object; Having a diffracted wave detecting means for irradiating an ultrasonic wave to the inspected object and detecting a diffracted wave from the discontinuous portion, wherein the reflected echo detecting means and the diffracted wave detecting means are integrally formed. Are moved simultaneously along the same inspection part.

(Action) According to the ultrasonic inspection method of the present invention, the position of the welding defect in the plate surface direction is detected by the reflected echo detection step, and the position of the welding defect in the plate thickness direction is detected by the diffraction wave detection step. It can be detected accurately.

Further, since the position of the defect detected in the reflected echo detecting step and the position of the defect detected in the diffracted wave detecting step can be easily adjusted, the position of the defect in the three-time direction can be accurately detected. In the case where the same defect detection image is created in the reflection echo detection step and the diffraction wave detection step, both steps can be processed at one time, so that the automation of the determination is facilitated. .

Further, according to the ultrasonic inspection apparatus of the present invention, the movement between the reflected echo detecting means and the diffracted wave detecting means becomes easy.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ultrasonic inspection method and apparatus according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows functional blocks of an ultrasonic inspection apparatus 1 according to the present invention. The ultrasonic inspection apparatus 1 includes a discontinuous portion 3 that is different from a regular material, such as a space, a foreign substance, and a fusion defect existing inside and outside a welded portion 3 of a pipe 2, which is an inspection object.
1 (FIG. 5), a reflected echo detecting means 10 for detecting the position in the plate surface direction, a diffracted wave detecting means 11 for detecting the position of the discontinuous portion 31 in the plate pressure direction, and these reflected echo detecting means 1
Scanning means 12 for moving the zero and diffracted wave detecting means 11 along the welded portion 3 and control means 1 for controlling the scanning means 12
3 is provided.

The ultrasonic inspection apparatus 1 includes a defect identification support device 14 for determining whether or not the discontinuous portion 31 detected by the reflected echo detecting means 10 and the diffracted wave detecting means 11 is a defect. A defect classification unit 15 for classifying defects determined by the identification support device 14 according to a predetermined standard; and an output unit 16 for outputting a classification result of the defect classification unit 15
And a storage unit 17 for storing processing data in the defect identification support device 14 and the defect classification unit 15.

When an ultrasonic wave is incident on the inspection object 2 and there is a defect, that is, a discontinuous portion 31 (FIG. 5), the reflected echo detecting means 10 changes the sound velocity at the discontinuous portion 31 to a normal material around the discontinuous portion 31. In this case, ultrasonic waves are incident on the welded portion 3 and reflected echoes reflected from the discontinuous portion 31 are detected. By analyzing this reflected echo by another means, the position of the discontinuous portion 31 in the plate surface direction can be identified. As the reflected echo detecting means 10, the one used in the conventional ultrasonic flaw detector can be used, and a detailed description is omitted here.

The diffraction wave detecting means 11 is a well-known TOF.
D (Time Of FlightDiffraction)
on) method. In this TOFD method,
As shown in FIG. 2, an ultrasonic oscillation probe 11 a and a reception probe 11 b are arranged on the inspection portion of the inspection object 2, here, on both sides of the welded portion 3. And the oscillation probe 11a
The ultrasonic wave is radiated at an angle capable of covering the entire thickness of the welded portion 3.

Then, in the receiving probe 11b, the lateral wave Sa passing through the shortest distance and the discontinuous portion 31
, A diffracted wave Sc diffracted at the lower end of the discontinuous portion 31, and a reflected echo Sd reflected at the bottom of the inspection object 2. FIG. 3 shows the reception waveform. Here, the reception time difference between the lateral wave Sa and the diffracted waves Sb and Sc corresponds to the distance between the upper end and the lower end of the discontinuous portion 31 from the surface of the inspection object 2. Therefore, by analyzing this time difference, the position of the discontinuous portion 31 in the plate thickness direction can be accurately detected.

The diffracted wave detected in this way is
As shown in FIG.
Can be easily identified. In FIG. 4, the horizontal axis indicates the depth, and the vertical axis indicates the distance of the measurement point from the reference point.
This diffracted wave detecting means 11 and the above-mentioned reflected echo detecting means 1
“0” is integrally formed and moves at the same time.

In FIG. 1, a scanning unit 12 uses, for example, a rail 4 used for moving a welding rod at the time of welding of a welding portion 3 and uses a reflected echo detecting means 10 and a diffracted wave detecting means 1.
1 is moved along the weld 3. The control unit 13 controls a driving unit (not shown) such as a motor of the scanning unit 12 so that the reflected echo detecting unit 10 and the diffracted wave detecting unit 11 are at least two in the axial direction and the circumferential direction of the pipe 2. The vehicle is driven in a zigzag manner at various pitches.

The defect identification support device 14 includes a reflected echo cell creating unit 20 for creating a cell described later from the reflected echo detected by the reflected echo detecting unit 10, and a cell based on the diffracted wave detected by the diffracted wave detecting unit 11. , A defect existence area setting means 22, a defect identification means 23, a display means 24, and a correction means 25.

In the reflection echo cell creating means 20, FIG.
As shown in the figure, all the discontinuous portions 31 detected by the reflection echo detecting means 10 are converted into a flat surface 32 corresponding to the surface of the welded portion 3.
Create a figure projected on. Then, the projection is displayed on the display means 24.

At this time, the waveform of the reflected pulse from the discontinuous portion 31 detected as shown in FIG. 6 is also displayed as an A scope. Also, as shown in FIG. 7, a diagram in which all the detected discontinuous portions 31 are projected on a plane 150 corresponding to a cross section in the longitudinal direction of the welded portion 3 and a plane 151 corresponding to a cross section in the width direction of the welded portion. Is displayed as a B scope. And the figure which projected all the discontinuous parts 31 on the above-mentioned plane 32 is displayed as a C scope as shown in FIG.

As shown in FIG. 9, the diffraction wave cell forming means 21 converts all the discontinuous portions 31 detected by the diffraction wave detecting means 11 into a plane 1 corresponding to a longitudinal section of the welded portion 3.
52 and a diagram projected on a plane 153 corresponding to a cross section of the welded portion 3 in the width direction are created, and are displayed on the display means 24 as a D scope.

When a reflected echo is displayed as the above-mentioned A scope, as shown in FIG.
20 is divided into cubic blocks 121 each having a predetermined size, for example, each side having a size of 1 mm, and the discontinuous portion 31 detected in each block 121, that is, the size of the reflected echo is recorded. The reflected echo is recorded for each block 121 in a total of four types of direct and reflected in the right and left flaw detection directions. In the defect inspection range 120, a heat affected zone in which a defect may be generated by welding can be appropriately specified.

In this manner, the discontinuous portion 31 is formed on the surface 32
After that, as shown in FIG. 11, the area where the discontinuous portion 31 is continuous on the surface 32 is defined as cells 33a, 33b,.
Create as That is, a plurality of discontinuous portions 31 of the welded portion 3 exist in the three-dimensional direction. When the plurality of discontinuous portions 31 are projected onto the surface 32 of the welded portion 3 in the two-dimensional direction, in this example, The continuous range is the cells 33a, 33b
・ ・

The defect-existing area setting means 22 determines a defect-existing area 34a, which is determined to have a possibility that a defect exists, based on the distribution of the cells 33a, 33b,. 34b ... are set. That is, in the defect existing area setting means 22, the discontinuous portion 3
The reflected echo from 1 is detected at a specified detection level, for example, -6d.
Cut with B Next, the incident direction and reflection position of the ultrasonic wave with respect to the extracted reflected echo are analyzed, and the range in which the possibility of a defect is recognized is determined as the defect existing areas 34a, 34
b ...

In the defect identification means 23, the cells 33 in the defect existing areas 34a, 34b.
.. are identified as defect echoes or shape echoes representing the surface of the pipe. That is, in the defect identification means 23, first, as shown in FIG. 12, the approach limit distances a and b to the bead of the welded portion 3 of the reflected echo detection probe 10 during inspection, the standard bead width C, the flaw detection plate thickness, Based on D and the incident angle θ of the ultrasonic waves 35 and 37 at the closest position of the reflection echo detection probe 10, the setting of the defect detection section and the area division are performed as follows.

In setting the defect inspection cross section, first, the center axis 4 of the weld bead 3 is placed inside the cell display ranges X1 and X2.
Lines 42 and 43 parallel to the central axis 41 are drawn at positions separated by a predetermined distance in the directions A and B from 1, and a defect extraction range Y 1, Y 2 is defined between the central axis 41 and the lines 42 and 43.
And The defect extraction ranges Y1 and Y2 correspond to the welding beads 3
And the heat-affected zone by welding, which is the minimum necessary range in which there is a possibility that a defect may occur.

Next, a straight line 44 separated by a distance L from the back surface of the pipe 2 and a predetermined distance Z 1 in the direction A or B from the center axis 41 of the weld bead 3 are located within the cross section of the defect extraction ranges Y 1 and Y 2. Straight lines 45 and 46 separated by two and a straight line 47 connecting the upper surface of the pipe 2 are drawn. These distances L, Z1,
For Z2, an optimum value is set by changing the welding method and the thickness of the pipe 2 in advance by experiments, and this is stored in a database, and the most effective value is obtained from the database according to the welding method and the thickness of the pipe 2 during actual welding. Typical values are selected. The straight line 36 corresponds to the back surface of the pipe 2.

Thereafter, as shown in FIG.
The range surrounded by 7, 46, 36 is defined as three areas H1, M
1 and L1. Area H1 is straight line 35, 46, 4
The area surrounded by 7 and the area M1 are straight lines 46, 35, 4
The area surrounded by 7, 42, and 44, the area L1 is a straight line 4
6, 44, 42, and 36.

Similarly, the range surrounded by the straight lines 45, 47, 43 and 36 is divided into three areas H2, M2 and L2.
Here, area H2 is a range surrounded by straight lines 47, 45, and 37, and area M2 is straight lines 45, 37, 47, 43, and 44.
, The area L2 is defined by straight lines 45, 44, 43,
The area is surrounded by 36.

Next, each area H1, H2, M1, M2,
It is determined whether the reflected echo detected for each of L1 and L2 is a defect echo or a shape echo. In this case, the detected reflected echoes are first divided into four groups as follows. That is, as shown in FIG. 14, the grouping is performed based on the incident directions of the ultrasonic waves 35 and 37 and the incident ultrasonic waves 3 and 37.
In this example, the incident direction is divided into the A direction on the left side of the welded portion 3 in the drawing and the B direction on the right side in the drawing. The reflection condition is divided into direct reflection and single reflection. The direct irradiation means that the ultrasonic waves 35 and 37 incident from the ultrasonic
In this case, the light is not reflected by the back surface 36 and is directly incident on the discontinuous portion 31 (solid line in the figure).

The single reflection is a case where the ultrasonic waves 35 and 37 incident from the ultrasonic detecting means 11 are reflected once by the back surface 36 and enter the discontinuous portion 31 (broken line in the figure). That is, here, the detected reflected echo is caused by the ultrasonic wave 35 (solid line) directly radiated from the A direction, the ultrasonic wave 35 reflected once by the A direction (broken line), and the ultrasonic wave directly radiated from the B direction. The sound wave 37 (solid line) and the ultrasonic wave 37 (broken line) reflected once from the direction B are divided into four groups.

Next, from the grouped reflection echoes, reflection echoes of a predetermined level or less, that is, reflection echoes considered to be caused by noise are identified. FIG. 15 shows an example of the noise filter 130 used here. The noise filter 130 removes echoes other than reflected echoes from the defect and echoes that can be ignored in the determination. For example, when a direct echo in the A direction is input (step 131), the echo is identified by the filter echo level (step 131). Step 132). Here, a difference between a predetermined value or less and a value exceeding the predetermined value is distinguished.

Next, a grouping process for echoes exceeding a predetermined value is performed (step 133). Here, the connection and the break of the data at the detection level (determined by the standard) are read from the three-dimensional data which is a set of cell images, and 1
Seeking the range of one echo. In addition, here is still 4
Each type of three-dimensional data is used. It is step 140 described later that the determination process is performed by combining the four types of results.

After performing the grouping process in step 133, identification based on the filter size is performed (step 13).
4). Here, if the grouping process performed in step 133 results in a group having an extremely small size, the group is not created from an echo from a defect, but is likely to be noise. Is small so that it does not affect the judgment, and is therefore distinguished from the defect. In addition, processing is performed by determining how many pieces of data are formed into one group in the grouping processing.

Next, the maximum echo position of each group is detected (step 135), and then the maximum echo position classification processing is performed (step 136). Here, the maximum echo position of each group is determined, and the position is determined by the six areas H described above.
1, H2, M1, M2, L1, L2. If there are two maximum echoes in the group, the one closer to the center of the group is adopted. Then, the maximum reflected echoes of each group are put together (step 137),
Whether or not the largest reflected echo of each group is defective is identified by its position (step 138).

Next, the maximum reflected echo of each group is checked against the identification criterion stored in the database to determine whether or not this is a defective echo (step 139).
This discrimination criterion is obtained by experiment, and
Each of the areas H1, H2, M1, M2, L1, and L2 can be separately defined.

That is, the identification criterion is, for example, as shown in FIG.
In the following description, the M2 area will be described. Once reflection of the ultrasonic wave 35 incident from the A direction by the discontinuous portion 31a (broken line)
When the maximum reflection echo by the group is detected as the direct reflection (solid line) group of the ultrasonic wave 37 incident from the B direction or the maximum reflection echo by the single reflection (dashed line) group, this is regarded as a defect echo, The discontinuous portion 31a corresponding to the defect echo is defined as a defect.

On the other hand, when the single reflection group in the direction A detects the reflection echo as the maximum reflection echo but the direct reflection group or the single reflection group from the direction B does not detect the reflection echo as the reflection echo, the reflection echo is detected. It is specified that the echo is a shape echo and not a defect echo, that is, the discontinuous portion 31a detected here is not a defect.

The above identification criteria are valid for the M2 area, but give different results, for example, in the opposite M1 area. That is, the discontinuous portion 31b of the M1 area is
The maximum reflection echo is detected in the single reflection group from the direction, and the maximum reflection echo is not detected in the direct reflection group or the single reflection group from the B direction. However, since the discontinuous portion 31b is defective, it is a defective echo in this case. Must be identified. Therefore, the identification criterion for the M1 area is M
This is different from the identification criteria for the two areas. The same applies to other areas, and the identification criterion is set for each area as described above. This defect echo identification processing
All cells 3 in the defect existing areas 34a, 34b,...
3a, 33b,...

After the defect is identified by comparison with the identification criterion in step 139 of FIG. 15, a grouping process is performed (step 140). Here, four types of data of the group identified as a defect in step 138 are
The maximum echo height and the area of the group are obtained as one group. Next, an identification process based on the final echo level and size is performed (step 141). Here, when the sensitivity is lowered to the level described in the standard, the plane size is obtained from the group area. Then, this is compared with the standard to finally determine whether or not it is a defect. In order to accurately identify defects, flaw detection and processing can be performed with a sensitivity higher than a specified sensitivity. This process is performed by a technician. Finally, the reflected echoes other than the defect are distinguished from the defect (step 14).
2).

Although the above description has been made with respect to the direct echo in the direction A, the same applies to the single reflection echo in the direction A, the direct echo in the direction B, and the single reflection echo in the direction B. The description is omitted.

In FIG. 1, a display means 24 is an arbitrary one of the outputs of the reflected echo cell creating means 20 and the diffracted wave cell creating means 21, the output of the defect existing area setting means 22 and the output of the defect identifying means 23. Are displayed simultaneously or separately. As the output means 24, a CRT (cathode ray tube), an LCD (liquid crystal display), or the like can be used.

The correcting means 25 is for correcting the output of the reflected echo cell generating means 20, the diffracted wave cell generating means 21, the defect area setting means 22 or the defect identifying means 23. Can be used. The operation of the correction unit 25 is performed by the display unit 24.
You can do it while watching.

The classifying unit 15 classifies the defect output from the defect identifying unit 23 of the defect identification supporting device 14 according to a predetermined standard. The output means 16 outputs the defect classification of the classification means 15, and a printer or the like can be used. The storage means 17 stores at least the outputs of the reflected echo cell creating means 20, the diffracted wave cell creating means 21, the defect existing area setting means 22, the defect identifying means 23, or the classifying means 15. You can also remember.

As described above, in the ultrasonic inspection apparatus 1, the grouping is performed without deleting all the discontinuous portions 31 having the possibility of a defect, and the defect detection range Y1,
Y2 is divided into six areas H1, H2, M1, M2, L1, L
Since each of the areas is divided into two areas, a total of four groups of reflected echoes of direct and single reflections in two directions A and B are detected, and a defective echo is detected by comparing each reflected echo with an identification standard. Data processing can be performed automatically, and defects can be accurately detected in a short time.

Further, the cell, the defect existing area, and the defect echo are displayed, and the inspection technician determines whether or not the correction is necessary by looking at the cell, and inputs the correction data when the correction is necessary, and corrects the correction. As a result, the flexibility of the system can be increased and the reliability can be increased. Further, since the processed data can be recorded in the recording means 17, the reproducibility of the data is excellent.

FIG. 16 shows the configuration of the ultrasonic inspection apparatus 1. The ultrasonic inspection apparatus 1 includes a general control unit 51 that performs overall control and data processing, an ultrasonic pulsar receiver unit 52 that transmits and receives ultrasonic waves, a scanner control unit 53 that controls a probe, And a scanner 54 as a child.

The general control unit 51 includes a CPU 61 for controlling each unit and performing data processing, a timing circuit 62 for managing operation timing of each unit, and an A / D converter 63.
, A monitor 64, a hard disk 65 for storing detection data, a PD 66 for storing waveforms, and a keyboard 67 and a mouse 68 for data input.

The CPU 61 includes the above-described cell creation means 21,
It functions as a defect area setting unit 22, a defect identification unit 23, and a classification unit 15. The monitor 64 is a display unit 2
4 and the hard disk 65 and the PD 66 function as the storage unit 17. The keyboard 67 and the mouse 68 function as the correction unit 25. The ultrasonic pulsar receiver unit 52 includes a 4ch main amplifier 71,
A 2ch main amplifier 72 and a 6ch remote pulser receiver 73 are provided.

The scanner control unit 53 includes a probe scanning controller 75 and an I / F 76 for outputting a position signal.
CPU 77 for scanning control and R for storing control software.
OM78. Probe scanning controller 7
5. The CPU 77 and the ROM 78 correspond to the control unit 13 described above.
Function as

The scanner 54 includes a probe scanning mechanism 81
And a reflection echo detection probe 10 and a diffraction wave detection probe 11, a sound anisotropy measurement probe 83, and a bead position detection unit 84. The probe scanning mechanism section 81 functions as the above-described scanning means 12, and includes a probe 10 for detecting a reflected echo, a probe 11 for detecting a diffracted wave, a probe 83 for measuring sound anisotropy, and a bead position detecting section. 84 is moved along the rail 4 (FIG. 1).

The reflection echo detecting probe 10 is
An ultrasonic wave is incident on the device and the reflected echo is detected. The probe 11 for detecting a diffracted wave detects an diffracted wave diffracted at the discontinuous portion 31 by applying ultrasonic waves to the welded portion 3. Further, the bead position detecting section 84 detects the position of the welded portion 3. The probe scanning mechanism 81 is controlled based on the detection result of the bead position detector 84. Table 1 shows the specifications of each unit described above.

[0056]

[Table 1]

Next, an example of the defect inspection processing by the ultrasonic inspection apparatus 1 will be described in detail with reference to FIG. FIG. 17 shows a procedure of the defect inspection processing 100 by the ultrasonic inspection apparatus 1. In the defect inspection processing 100, first, the primary inspection of the welded portion 3 is performed (step 101).

In this primary flaw detection, as shown in FIG. 18, the reflected echo detecting probe 10 of the scanner 54 (FIG. 16) is used.
And a diffraction wave detecting probe 11 (FIG. 16 shows a receiving probe 1).
1b only, the oscillation probe 11a scans the opposite side of the weld 3 at the same pitch as the reception probe 11b).
The probe 83 for sound anisotropy measurement is scanned at a relatively coarse pitch, for example, in a reciprocating motion of 5 mm pitch in the axial direction of the pipe 2 and at a pitch of 5 mm in the circumferential direction. A reflected echo and a diffracted wave are detected. The probe 10 for detecting the reflected echo, the probe 11 for detecting the diffracted wave, and the probe 83 for measuring the sound anisotropy are scanned while maintaining a predetermined interval. The bead position detector 84 (not shown) scans only in the circumferential direction of the pipe 2.

Next, as shown in FIG. 17, in the CPU 61 of the general control unit 51 (FIG. 16), the discontinuous portion 31 corresponding to the detected reflected echo and diffracted wave is projected on the same surface, and Cells 33a, 33b ...
(FIG. 11), and a cell (not shown) based on the diffracted wave is created (step 102), and subsequently the defect existing area 34
are set (step 103). Cells 33a, 33b,...
34b are displayed on the monitor 64 (FIG. 16).

Next, the defect existing areas 34a, 34b... Displayed on the monitor 64 are corrected.
Is displayed on the monitor 64 (FIG. 16). Next, the defect existing areas 34a and 34b displayed on the monitor 64
Are required to be corrected by the inspection technician (step 104). If it is determined that correction is necessary, the keyboard 67
(FIG. 16) or correction data is input from the mouse 68 to correct the defect existing areas 34a, 34b,... (Step 105).

Next, secondary flaw detection is performed (step 10).
6). As shown in FIG. 11, the secondary flaw detection includes a defect existing area 34a, 34b.
The probe for detecting the reflected echo 10, the probe for detecting the diffracted wave 11, and the probe 83 for measuring the anisotropy of the scanner 54 have a finer pitch than the primary flaw, for example, 1 in the axial direction and circumferential direction of pipe 2
The reflected echo is detected by scanning at a pitch of mm.

Next, as shown in FIG. 17, cells 40a to 40g of the discontinuous portion 31 corresponding to the detected reflected echo are created (step 107). Subsequently, cells 40a-4
It is determined whether or not the reflected echo within 0 g is a defective echo (step 108). The cells 40a to 40g are displayed on the monitor 64. For example, when the cell 40b is a defect echo, this is identified by, for example, color coding. Thereafter, the depth of the defect is determined by the TOFD method described above (step 109).

Next, the inspection technician determines whether or not the defect echo 40b displayed on the monitor 64 needs to be corrected (step 110). If it is determined that the correction is necessary, the keyboard 67 or the mouse is used. Correction is input by inputting the correction data from step 68 (step 111). Next, the defect echo is classified according to a predetermined standard (step 112), the classification result is printed out (step 113), and the defect inspection processing 100 ends.

In this flaw detection processing 100, the primary flaw detection (step 101) performs the defect existence areas 34a, 3a.
4b is set (step 103), and the defect echo is identified (step 108) by performing a secondary flaw detection (step 106) on a portion wider than the defect existing areas 34a and 34b by a predetermined range 2W (step 108). The flaw detection time can be greatly reduced as compared with the case where flaw detection is performed at a fine pitch. Further, since the depth of the defect is determined by the TOFD method (step 109), the position of the defect can be accurately detected.

In the above-described embodiment, a case has been described in which primary flaw detection is performed at a coarse pitch and secondary flaw detection is performed at a fine pitch. However, flaw detection can be performed at a fine pitch from the beginning. The data processing time is shortened by using a part of the reflected echo detected by the reflected echo detecting probe 10 and the diffracted wave detected by the diffracted wave detecting probe 11 for data processing. be able to.

For example, as shown in FIG. 20A, when the horizontal axis represents time and the vertical axis represents the height of a reflected echo, for example, 5
In the case of sampling at 100 MHz at an ultrasonic frequency of MHz, there are 20 pieces of detection data in one ultrasonic wave.
The highest value of every 10 data is detected from these 20 data,
When the waveform of the reflected echo is formed, the number of data used for data processing is 10% of that when the data is sampled at 100 MHz, as shown in FIG. 4B, and the data processing time can be greatly reduced. In this case, the most important echo height in reflected echo detection can be accurately detected without change. Further, the change in the position on the time axis is extremely small, and does not affect the inspection result. The same processing is performed for the diffracted wave.

The data to be used is not limited to the maximum height, but a plurality of data from the maximum value to a predetermined rank can be used. The reflected echo and the diffracted wave formed by the maximum wave height extracted here are recorded and left.

At the ultrasonic frequency of 5 MHz, the results shown in FIG. 21 were obtained as a result of measuring the sampling frequency of data collection, the accuracy of data processing, and the time required for data processing. As can be seen from this result, the transfer time becomes shorter as the sampling frequency is smaller,
Data accuracy decreases. Conversely, the higher the sampling frequency, the longer the transfer time and the higher the data accuracy.

In order to make both the data transfer rate and the data accuracy practicable, the sampling frequency for data collection is preferably selected from 50 MHz to 300 MHz, and particularly preferably from 100 MHz to 300 MHz.
In this method, the maximum echo is not produced even if the extraction frequency is lowered, but the extraction frequency needs to be 5 MHz or more in order to improve the positional accuracy, and particularly preferably 10 MHz or more. With an ultrasonic frequency of 2 MHz, the extraction frequency can also be reduced.

In the above-described embodiment, the probe 10 for detecting the reflected echo and the probe 11 for detecting the diffracted wave are separately provided as shown in FIG. It can be used as a common probe and electrically switched. Further, in the above embodiment, the case where the present invention is applied to the inspection of the welded portion of the pipe has been described, but the present invention can be applied to the inspection of the welded portion of various materials.

[0071]

As described above, according to the ultrasonic inspection method of the present invention, the position of the welding defect in the plate surface direction is detected by the reflection echo detecting step, and the thickness of the welding defect is detected by the diffraction wave detecting step. Since the position in the direction can be detected, the position of the defect can be accurately detected, and can be effectively used for welding design and the like.

When the reflected echo detecting step and the diffracted wave detecting step are continuously performed along the same inspection portion, the defect detected in the reflected echo detecting step and the defect detected in the diffracted wave detecting step are detected. Since the alignment with the defect becomes easy, the processing time can be reduced. Further, when the same defect judgment image is created in the reflection echo detection step and the diffraction wave detection step, the efficiency of the defect identification work is improved.

Further, according to the ultrasonic inspection apparatus of the present invention, the movement between the reflected echo detecting means and the diffracted wave detecting means becomes easy, so that the configuration can be simplified.

[Brief description of the drawings]

FIG. 1 is a diagram showing functional blocks of an ultrasonic inspection apparatus according to the present invention.

FIG. 2 is a diagram illustrating a method of detecting a position of a defect in a thickness direction of the ultrasonic inspection apparatus according to the present invention.

FIG. 3 is a diagram illustrating a method of detecting a position of a defect in a thickness direction of the ultrasonic inspection apparatus according to the present invention.

FIG. 4 is a diagram illustrating a method for detecting the position of a defect in the thickness direction of the ultrasonic inspection apparatus according to the present invention.

FIG. 5 is a sectional view taken along line AA of FIG. 1;

FIG. 6 is a diagram showing a waveform of a reflected echo.

FIG. 7 is a projection view of a reflection echo.

FIG. 8 is a projection view of a reflection echo.

FIG. 9 is a projection view of a diffracted wave.

FIG. 10 is a diagram showing a block for cell creation.

FIG. 11 is a diagram showing a distribution state of cells.

FIG. 12 is a diagram illustrating a method of dividing a defect detection area into areas.

FIG. 13 is a diagram showing an area of a defect detection range.

FIG. 14 is a diagram showing an incident direction and a reflection condition of an ultrasonic wave.

FIG. 15 is a diagram illustrating a noise filter.

FIG. 16 is a diagram showing a configuration of an ultrasonic inspection apparatus according to the present invention.

FIG. 17 is a diagram showing a procedure of defect processing.

FIG. 18 is a diagram showing a scanning method of the probe.

FIG. 19 is a diagram showing a distribution state of cells in secondary flaw detection.

FIG. 20 is a diagram showing detection data of a reflected echo.

FIG. 21 is a diagram illustrating a relationship among a sampling frequency, data transfer time, and data processing accuracy.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultrasonic inspection apparatus 2 Piping (inspected object) 10 Probe for reflection echo detection 11 Probe for diffraction wave detection 31 Discontinuous part

Claims (4)

[Claims] A reflection echo detecting step of irradiating an ultrasonic wave to the inspection object and detecting a reflection echo of the ultrasonic wave reflected at a discontinuous portion of the inspection object; and irradiating the ultrasonic wave to the inspection object. And a diffracted wave detecting step of detecting a diffracted wave from the discontinuous portion, wherein the reflected echo detecting step and the diffracted wave detecting step are performed simultaneously. 2. The ultrasonic inspection method according to claim 1, wherein the reflection echo detection step and the diffraction wave detection step are performed continuously along the same inspection part. 3. The ultrasonic inspection method according to claim 1, wherein the reflection echo detection step and the diffracted wave detection step create the same defect detection image. 4. A reflection echo detecting means for irradiating an ultrasonic wave on the inspection object and detecting a reflection echo of the ultrasonic wave reflected on a discontinuous portion of the inspection object, and irradiating the ultrasonic wave on the inspection object. And a diffracted wave detecting means for detecting a diffracted wave from the discontinuous portion, wherein the reflected echo detecting means and the diffracted wave detecting means are integrally formed and simultaneously moved along the same inspection portion. An ultrasonic inspection apparatus characterized in that the inspection is performed.