JP2002195988A - Ultrasonic testing device and ultrasonic testing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic testing device and an ultrasonic testing method enabling a high-precision identification as to whether to be a defect or not. SOLUTION: In this testing device, a peak detecting means 51 calculates the height and location of an echo for each peak based on a reflection echo received by a probe 10, and a back wave echo detecting means 52 uses the result obtained by the peak detecting means 51 to calculate the peak of maximum echo height for each cross section perpendicular to a weld line, identifying the back wave echo location on the cross section based on the obtained peak echo location. Further a defect identifying means 53 defines a reference frame with the back wave echo location as its origin for each cross section perpendicular to a weld line and indicates each echo location as an position coordinate on the reference frame. Then the echo is identified as a defective echo if the echo location shown by using the reference frame is contained in a specified range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic inspection apparatus and an ultrasonic inspection method for non-destructively inspecting a welded portion of a steel material using ultrasonic waves.

[0002]

2. Description of the Related Art Conventionally, an ultrasonic flaw detector has been known as a device for non-destructively inspecting a defect which may occur in a welded portion of a steel material. Such an ultrasonic flaw detector uses a probe to inspect a defect in a body to be inspected. A guide rail is attached to the object to be inspected in parallel with the welding line of the welding portion, and the probe can move in a direction parallel to and perpendicular to the guide rail. The probe makes an ultrasonic wave incident on the object to be inspected and receives the ultrasonic wave (reflected echo) reflected by a reflection source in the object to be inspected. When an ultrasonic wave is propagated through an object to be inspected, if there is a non-uniform portion such as a defect or a welded portion, the ultrasonic wave is reflected using the non-uniform portion as a reflection source. For this reason, the reflected echo received by the probe includes not only the defect echo reflected by the defect, but also the shape echo reflected by the excess of the welded portion.

[0003] The ultrasonic flaw detection apparatus specifies the echo height and the position of the reflection source based on the reflection echo received by the probe. At this time, the position of the reflection source is determined in a coordinate system whose origin is a predetermined position on the welding line. Specifically, first, after determining the position of the reflection source with respect to the probe, the position of the probe with respect to a predetermined position on the guide rail, the distance between the guide rail and the welding line, and the width of the extra welded portion Based on the above, the position of the reflection source in the coordinate system is calculated. The ultrasonic flaw detector identifies whether each reflection source is a defect or not by examining the positional relationship between each reflection source and the weld.
Then, a flaw detection image in which the echo height is plotted at the position of each defect is created and displayed on the screen of the display device.

[0004]

However, since the guide rail is usually attached to the test object by a magnet, the mounting accuracy of the guide rail is not very good.
In addition, the margin of the welded portion does not always have a constant width, and there is some variation. Furthermore, the sound speed inside the test object may not be uniform depending on the test object, and in this case, the refraction angle of the flaw detection may change during the flaw detection. As described above, in the conventional ultrasonic flaw detector, since the position of the reflection source is specified in the coordinate system having the origin at a predetermined position on the welding line, the mounting error of the guide rail, the variation of the width of the excess, the refraction If there is an angle shift or the like, the position of the reflection source in the coordinate system cannot be obtained accurately. For this reason, for example, there is a problem that it is not possible to judge a defect with high accuracy by judging a defect echo as a shape echo or conversely, judging a shape echo as a defect echo.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method capable of accurately determining whether or not a defect exists. is there.

[0006]

An ultrasonic flaw detector according to the present invention for achieving the above-mentioned object irradiates an ultrasonic wave into an object to be inspected, and is reflected by a reflection source in the object to be returned. A probe for receiving a reflected echo, scanning means for scanning the probe at a predetermined pitch in a direction orthogonal to the welding line at each position along the welding line of the test object, and the scanning means Based on the reflected echo received by the probe during scanning by the first processing means for obtaining the echo height of each peak and the position of the reflection source corresponding to each peak, obtained by the first processing means Using the result, in each cross section perpendicular to the welding line, the peak at which the echo height is the maximum,
Second processing means for specifying the position of the shape echo from the weld in the cross section based on the position of the reflection source corresponding to the obtained peak, and output means for outputting the result obtained by the second processing means , Are provided.

An ultrasonic flaw detector according to the present invention for achieving the above object receives an ultrasonic wave incident on an object to be inspected, and receives a reflected echo reflected by a reflection source in the object to be inspected and returned. Probe, scanning means for scanning the probe at a predetermined pitch in a direction perpendicular to the welding line at each position along the welding line of the object to be inspected, and Based on the reflected echo received by the probe, the first processing means to determine the echo height of each peak and the position of the reflection source corresponding to each peak, using the result obtained in the first processing means Determining the peak at which the echo height is maximum in each cross section perpendicular to the welding line, and specifying the position of the shape echo from the weld in the cross section based on the position of the reflection source corresponding to the obtained peak. Two processing means and the welding A coordinate system is set with the origin of the position of the shape echo specified by the second processing means for each cross section perpendicular to the position, and the position of each reflection source determined by the first processing means is represented by position coordinates in the coordinate system. A defect identification unit that identifies the reflection source as a defect when the position of the reflection source is represented and is included within a predetermined range using the coordinate system. And an output unit for outputting the obtained result.

In order to achieve the above object, an ultrasonic flaw detection method according to the present invention is characterized in that a probe is provided at a predetermined pitch in a direction orthogonal to the welding line at each position along the welding line of the test object. A first step of irradiating an ultrasonic wave from the probe into the object to be inspected while scanning, and receiving a reflected echo reflected by a reflection source in the object to be returned by the probe; Based on the reflected echo received by the stylus, the second step of determining the echo height of each peak and the position of the reflection source corresponding to each peak, using the result obtained in the second step,
A third for determining the peak having the maximum echo height in each cross section perpendicular to the welding line, and specifying the position of the shape echo from the weld in the cross section based on the position of the reflection source corresponding to the obtained peak. And a fourth step of outputting the result obtained in the third step to an output means.

According to another aspect of the present invention, there is provided an ultrasonic flaw detection method for detecting an object at a predetermined pitch in a direction orthogonal to the welding line at each position along the welding line of the inspection object. While scanning the probe, a first step of irradiating an ultrasonic wave from the probe into the object to be inspected, and receiving, by the probe, a reflected echo that returns after being reflected by a reflection source in the object to be inspected, Based on the reflected echo received by the probe, the second step of determining the echo height of each peak and the position of the reflection source corresponding to each peak, using the result obtained in the second step, A third for determining the peak having the maximum echo height in each cross section perpendicular to the welding line, and specifying the position of the shape echo from the weld in the cross section based on the position of the reflection source corresponding to the obtained peak. Process and for each section perpendicular to the weld line The coordinate system is set with the position of the shape echo specified in the third step as the origin, the position of each reflection source determined in the second step is represented by position coordinates in the coordinate system, and using the coordinate system. A fourth step of identifying the reflection source as a defect when the position of the reflection source represented by is included in a predetermined range, and a fifth step of outputting a result obtained in the fourth step And characterized in that:

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram of an ultrasonic flaw detector according to one embodiment of the present invention, FIG. 2 is a schematic plan view of a scanning device in the ultrasonic flaw detector, and FIG.
FIG. 4 is a diagram for explaining how to scan the probe in the ultrasonic flaw detector, and FIG. 4 is a diagram for explaining a recording range of data received by the probe.

As shown in FIGS. 1, 2 and 3, the ultrasonic flaw detector comprises two probes 10, 10, a scanning device 20 provided for each probe, and an AD converter. 30,3
0, a storage unit 40, a control unit 50, and a display device 60.

This ultrasonic flaw detector is for detecting a defect in the welded portion 4 of the test object 2. In particular,
In the present embodiment, the inspection object 2 is formed by providing a V-shaped groove between two plate-shaped steel materials and butt-welding them. At this time, a surplus in which the weld metal rises from the surface is formed at the groove. For example, FIG.
As shown in FIG. 5, a wide margin is formed on the upper side of the steel material, and a narrow margin is formed on the lower side.

In the following, a direction parallel to the welding line of the weld 4 is defined as an X direction, a direction parallel to the surface of the test object 2 and orthogonal to the X direction is defined as a Y direction, and an X direction. The depth direction of the test object 4 orthogonal to the Y direction is defined as a Z direction.
Here, the welding line is a virtual line when the welded portion is represented as one line.

The probe 10 receives an ultrasonic wave (reflected echo) that enters an ultrasonic wave into the inspection object 2 and is reflected by a reflection source in the inspection object 2 and returned. Since a known probe can be used as the probe 10, a detailed description of the structure of the probe 10 is omitted here.

The scanning device 20 connects the probe 10 to the object 2 to be inspected.
It scans on the upper side, and has a guide rail 21 and an arm 22 as shown in FIG. The scanning device 20 is installed on the inspection object 2 such that the guide rail 21 is parallel to the welding line of the welding portion 4. Here, the guide rail 21
The distance between the welding line and the welding line of the welding portion 4 is set to a predetermined distance in advance.

The arm 22 extends in a direction (Y direction) orthogonal to the guide rail 21 and can move along the guide rail 21. The probe 10 is attached to the arm 22 and can move on the arm 22. Therefore, the probe 10 moves along the X direction by controlling the movement of the arm 22, and moves along the Y direction by controlling the movement of the probe 10 itself. The movement of the arm 22 and the probe 10 is as follows.
It is controlled by the control unit 50. Therefore, the control unit 50
Can easily calculate the X direction position of the arm 22 (probe 10) with respect to a predetermined reference position on the guide rail 21, and the Y direction position of the probe 10 with respect to the reference position.

In this embodiment, as shown in FIG. 3, the scanning device 20, that is, the probe 10 is arranged on the side where the wide margin is formed. Here, the side of the test object 2 that is the same as the side on which the probe 10 is disposed is referred to as “front side”, and the side of the test object 2 opposite to the side on which the probe 10 is disposed is referred to as “back side”. I will say. In addition, the surplus on the back side is also referred to as “uranami”.

The two probes 10, 10 are arranged on both sides of the weld 4, as shown in FIG. Generally, weld 4
The shape of the surplus is wavy, and the irregularities are severe. For this reason, if an ultrasonic wave propagating substantially perpendicularly to the surface of the surplus is used to check for a defect in the welded portion 4, the ultrasonic wave does not enter the welded portion 4 well. On the other hand, the base material of the test object 2 has a substantially constant shape. For this reason, defects of the welded portion 4 are to be examined using ultrasonic waves that proceed obliquely with respect to the surface of the base material. This is a so-called bevel flaw detection.

Each probe 10 is moved by a so-called vertical scanning. That is, the probe 10 moves at a predetermined scanning interval along the X direction as shown by a thick arrow in FIG. 3, and moves at a predetermined pitch along the Y direction at the position in the X direction. Then, the probe 10 performs a flaw detection operation every time it moves by a predetermined pitch along the Y direction.

When the flaw detection operation is started, first, the probe 10
Generates ultrasonic waves. Ultrasonic waves generated from the probe 10 are refracted at the interface between the probe 10 and the object 4 and enter the object 4. Here, the flaw detection refraction angle at the boundary surface is obtained from Snell's law based on the angle of incidence on the boundary surface and the speed of sound of the ultrasonic wave propagating in the test object 4. The ultrasonic wave that has entered the test object 4 propagates toward the weld 4. Then, the probe 10 receives the reflected echo returned by the ultrasonic wave being reflected by the reflection source.

Since the flaw detection angle is constant, the probe 10
Can be detected at a shallow position of the welded portion 4 when the probe 10 is located near the welded portion 4, and can be detected at a deep position of the welded portion 4 when the probe 10 is located far from the welded portion 4. it can. In particular, when flaw detection is performed on the front surface of the welded portion 4, the probe 10 is located far away from the welded portion 4, and the ultrasonic wave reflected once on the back surface of the test object 2 is used. Will be used. Thus, the probe 1
By scanning 0 at a certain pitch in the X direction at a certain position in the Y direction and performing flaw detection, a defect can be inspected in the depth direction of the welded portion 4 at the X direction position. In the present embodiment, such a flaw detection operation is performed for each probe 10 using the two probes 10.

FIG. 5A is a diagram showing an example of waveform data obtained when the probe 10 is located at a certain X-direction position and a certain Y-direction position. In FIG. 5A, the vertical axis represents the echo height, and the horizontal axis represents the beam path. The beam path is the distance that the ultrasonic wave has passed through the inspection object 2 from the incident point to the reflection source. Since the speed of sound of the ultrasonic wave propagating in the test object 2 is substantially constant, it can be said that the beam path represents the time required to propagate the distance.

The reflected echo received by the probe 10 includes a defect echo, a shape echo and a delayed echo. The defect echo is an echo that is reflected by a defect such as a flaw and returned to the probe 10. The shape echo means that the ultrasonic wave is reflected by
Is the echo that has returned. This is referred to as a “shape” echo due to the shape of the weld 4. In particular, when the ultrasonic wave emitted from the probe 10 does not reflect on the back surface of the test object 2 but directly enters the narrow margin on the back side, the ultrasonic wave is reflected there and probed as a large echo. Child 1
Returns to 0. In the following, the shape echo from the backside margin is also referred to as “backside echo”. Normally, the echo height of the shape echo is higher than the echo height of the defect echo, but the echo height of the defect echo may be higher depending on the degree of the defect.

Next, the delayed echo will be described. FIG.
FIG. 6 is a diagram for explaining a delayed echo. Now, FIG.
As shown in (a), a case is considered in which an ultrasonic wave is directly incident from the probe 10 to the backside extra. At this time, FIG.
As shown in FIG. 7, not only the large shape echo E10 but also typically two echoes E11 and E12 return to the probe 10 a little later than the shape echo E10 from the backside prosthesis. come. These echoes E11 and E12 are "lag echoes". The delayed echoes E11 and E12 are generated as follows. Transverse waves are used as ultrasonic waves generated by the probe 10. A transverse wave which is reflected in the opposite direction and returns to the probe 10 when it is incident on the backside bank is a shape echo E10. Further, when the ultrasonic wave is incident on the backside, longitudinal waves and transverse waves reflected in various directions are generated. Among the longitudinal waves generated here, for example, it propagates toward the front side swell, reflects there and returns to the back side swell as a longitudinal wave, and then reflects at the back side swell to become a transverse wave. Some return to the probe 10. What returned on this route is the delayed echo E11. Also, among the transverse waves generated at the backside, for example, it propagates toward the front side, reflects there, returns to the backside, and then reflects at the backside, and Something returns to child 10. What returned on this route is the delayed echo E12.

As described above, the reflection echo includes a defect echo, a shape echo, a delayed echo, and the like. When inspecting the welded portion 4, it is necessary to accurately identify the defect echo from the reflection echo. .

The AD converter 30 converts the flaw detection waveform data of the reflected echo received by the probe 10 into digital waveform data. For example, the echo height is 1-byte data and takes a value from 0 to 255. The digital waveform data is stored in the storage unit 40.

Incidentally, the flaw detection waveform data received by the probe 10 includes data on the reflected echo reflected far away from the weld 4. It is desirable to save all the flaw detection waveform data in the storage unit 40, but this would result in a very large amount of data. Therefore, in the present embodiment, as shown in FIG. 4, to be stored only data for the echo returned from a predetermined data recording range R within ₁ including a weld 4 in the storage unit 40. Data recording range R over which reflected echo is applied
Whether or not it has returned from within ₁ can be determined based on the position of the probe 10 and the beam path.

The control unit 50 controls scanning of the probe 10 and processes data obtained by the probe 10. As shown in FIG. 1, the control unit 50 includes a peak detection unit (first processing unit) 51, a flaw detection image data creation unit 52, a back wave echo detection unit (second processing unit) 53,
It has a defect identification unit 54 and a flaw detection image creation unit 55.

The peak detecting means 51 determines the echo height of each peak and the position of the reflection source (echo position) corresponding to each peak based on the reflected echo received by the probe 10. The flaw detection image data creation means 52 creates flaw detection image data using each echo position and echo height obtained by the peak detection means 51. Using the flaw detection image data, the back-wave echo detection means 53
The peak at which the echo height is maximum on the YZ plane at the direction position is determined, and the position of the back wave echo in the YZ plane is specified based on the determined echo position of the peak. Further, the defect identification means 54 sets an XYZ reference coordinate system having the origin of the position of the back-wave echo specified by the back-wave echo detection means 53 for each YZ plane at each X-direction position. XYZ for each determined echo position
When the echo position represented by the position coordinate in the reference coordinate system and the echo position represented by the XYZ reference coordinate system is included in a predetermined defect identification range, the echo is identified as a defect echo. The flaw detection image creation means 55 creates a flaw detection image in which the echo height is plotted at the echo position for each of the defect echoes, shape echoes, delayed echoes, etc. identified by the defect identification means 54.

The display device 60 includes a back-wave echo detecting means 53.
And the result obtained by the defect detection means 54 and the flaw detection image created by the flaw detection image creation means 55 are displayed.

Next, a procedure for processing data obtained by the probe 10 in the ultrasonic flaw detector of the present embodiment will be described.
FIG. 7 is a flowchart for explaining the processing procedure of the waveform data in the ultrasonic inspection equipment of the present embodiment. FIG. 8 is a diagram for explaining a method of detecting a back wave echo position, FIG. 9 is a diagram for explaining a defect identification range, and FIG. 10 is a diagram for explaining a method of creating a flaw detection image.

After the scanning and flaw detection operations of the probe 10 have been completed and the waveform data has been stored in the storage unit 40, the control unit 50 executes processing according to the flow of FIG. First, the peak detecting means 51 of the control unit 50 calculates the echo height and the echo position of each peak based on the waveform data (S
1). Specifically, the peak detecting means 51 first
Each peak is found from the waveform data as shown in (a), and the echo height and beam path are extracted for each peak. For example, for the peak P0, the echo height is E0 and the beam path is W0. The peak P1 has an echo height of E1 and a beam path of W1. Next, the peak detecting means 51 uses the extracted beam path and the flaw detection refraction angle for each peak,
Calculate the echo position. The echo position calculated here is
It is represented in an XYZ coordinate system with the reference position on the guide rail 21 as the origin, and is not represented in the XYZ reference coordinate system described above. For example, when the flaw detection angle is θ,
As shown in FIG. 5B, for the peak P0, the distance in the Y direction from the point of incidence of the ultrasonic wave to the reflection source is Y = W0 × sin.
and the distance in the Z direction is given by Z = W0 × cos θ. Since the position of the probe 10 in the XYZ coordinate system is known, the echo position for the peak P0 can be obtained. After that, the echo height is made to correspond to the echo position thus obtained,
Store to 0. The peak detecting means 51 performs the same processing for all the peaks of the waveform data as shown in FIG.

Next, the flaw detection image data creating means 52 creates flaw detection image data (S2). First, flaw detection image data creating unit 52 divides the data Coverage R ₁ as shown in FIG. 10 in a cell of a predetermined size. Where the cell is
It is basically a cube with a side length of 1 mm,
It can be set arbitrarily. Next, the flaw detection image data creating means 52 sets the echo height of each peak stored in the storage unit 40 by the peak detecting means 51 in a cell corresponding to an echo position represented by coordinates in the XYZ coordinate system. Thus, flaw detection image data is created. At this time, if it is necessary to set the peaks of the waveform data at different flaw detection points in the same cell, the data with the higher echo height is set. The flaw detection image data thus created is stored in the storage unit 40.

Next, the back wave echo detecting means 53 obtains the position of the back wave echo on the YZ plane at each X direction position using the flaw detection image data (S3). The process of obtaining the back wave echo position is performed as follows. The approximate location of the Uranami is known in advance. Penetration echo detection means 53, as shown in FIG. 8 (a), on the YZ plane at each X-direction position, the back wave echo detection range R ₂ so as to include the position P of the approximate to the presence of the back waves Set. For example, the approximate position P where the Uranami exists may be the lower part of the groove in the base material on the opposite side of the probe 10. In fact, the position of the Uranami fluctuates slightly due to the widening margin, but this need not be considered very strictly. The penetration echo detection range R ₂ is because it corresponds by setting some extent. Also, the penetration echo detection range R _2, for example, is set in the range of a square of length 6mm one side around the position P of the approximate to the presence of the back waves. This back wave echo detection range R
₂ can be set arbitrarily. Penetration echo detection unit 53, on the YZ plane at each X-direction position, the echo height penetration echo within the detection range R ₂ is Find the highest position (maximum echo position). Usually, the echo height of the back-wave echo is larger than the echo height of the defect echo, and thus the maximum echo position thus obtained is considered to be the back-wave echo position.

By the way, when or there is a large defect in the penetration echo within the detection range R _2, echo height of the defect echo is sometimes greater than the echo height of the penetration echo.
In this case, if the maximum echo position is simply set as the back-wave echo position, the defect echo position is set as the back-wave echo position.
Normally, the back wave echo position falls within a certain range when viewed from the X direction, and an echo position not included in this range cannot be considered as a back wave echo position. In the present embodiment, the maximum back-wave echo skip distance r is set, and the inside of a circle whose radius is the maximum back-wave echo skip distance r around a predetermined position on the YZ plane is defined as the range in which the back-wave echo position exists. And The maximum back wave echo skip distance r can be set arbitrarily.

The back-wave echo detection means 53 is
Position X_nMaximum echo position in the YZ plane at
(X_n, Y_n', Z_n′) When asked
Maximum echo position (X_n, Y_n', Z_n') And the X direction
Direction position X_nIn the X direction adjacent to the YZ plane at_n-1
Back wave echo specified in the previous scan on the YZ plane
Position (X_n-1, Y_n-1, Z_n-1) In the X direction X
_nAt the position projected on the YZ plane (X_n, Y_n-1, Z
_n-1)_nIs calculated. That is, D _n
= ｛(Y_n-1-Y_n′)²+ (Z_n-1−
Z_n′)²｝^1/2It is. This distance D_nIs the biggest Uranami d
When the distance is less than the co-skip distance r, the maximum echo
Position (X_n, Y_n', Z_n′) At the X direction position X_nAt
The back wave echo position on the YZ plane (X_n, Y_n, Z_n)
Is determined to be. On the other hand, the distance D_nIs the largest Uranami e-course
When the distance is larger than the kip distance r, the maximum echo position
(X_n, Y_n', Z_n′) Is the defect echo position
Judge, X direction position X_nUranami Eco on the YZ plane in Japan
-Position (X_n, Y_n, Z_n)
Set back wave echo position (X_n-1, Y_n-1,
Z_n-1) In the X direction X_nProjected on the YZ plane at
Position (X_n, Y_n-1, Z_n-1). Like this
Connecting the back wave echo positions in each YZ plane obtained by
As a result, a back wavy line is obtained. For each channel,
That is, the back wave echo position is different for each of the left and right probes 10.
You.

Next, on the YZ plane at each X-direction position, the defect identification means 54 sets the X-axis with the back-wave echo position as the origin.
Using the YZ reference coordinate system, the echo position of each echo obtained by the peak detecting means 51 is represented by position coordinates in the XYZ reference coordinate system (S4). Thereafter, the defect identification means 54
Identifies whether each echo obtained by the peak detecting means 51 is a defective echo (S5). This is performed as follows. In the present embodiment, as shown in FIG. 9, it is set to identify the range R ₃ in advance the defect. The defect identification range R ₃ is a range considered a defect exists is determined according to the shape of the groove. For example, V
In the case of shape groove, as shown in FIG. 9, it has a range of spread across the groove by a predetermined distance and defect identification area R _3.
Thus the defect identification range R _3, What was somewhat leeway so as to include a groove is, failing to precisely identify the location of the groove. XYZ
Each echo position represented in the reference coordinate system is a defect identification range R
₃ is determined. When the echo position is included in the defect identification range R ₃ determines the echo and a defect echo. On the other hand, when said echo is not included in the defect identification range R ₃ determines the echo is not a defect echo.

In the XYZ reference coordinate system, a range in which the Z-direction position is between the origin and a fixed height position above the origin and the Y-direction position is on the opposite side of the probe 10 from the origin, that is, FIG. range R ₀ in the echo included in the _(range hatched), even when it is contained even in the defect identification area R _3, is not determined that a defect echo. This is because such a range _R0 is a range in which a backwash is considered to exist. Thus, the defect identification area R _3, strictly speaking, a range excluding the common parts of the range hatched in FIG. 9, the range and the range R ₀ having been subjected to the shading.

Further, it is not necessary to make a strict judgment on a defect in the vicinity of a backwash. This is because a defect in the vicinity of the Uranami can be accurately determined by flaw detection by the probe 10 on the opposite side to the probe 10.

Next, the flaw detection image creation means 55
A flaw detection image is created based on the flaw detection image data and the defect identification result stored in the storage unit 0 (S6). Here, as the flaw detection image data, data obtained by setting the echo height in a cell corresponding to the echo position represented by coordinates in the XYZ reference coordinate system is used. Specifically, for example, plotting is performed by color-coding the flaw detection image data according to the echo height. This is performed for each peak echo. Thus, a flaw detection image is created. still,
The flaw detection image creating means 55 may plot only the peak echo whose echo height is equal to or more than a predetermined value (threshold). As a result, it is possible to remove echoes that are considered to be caused by noise. This threshold can be set arbitrarily.

When a three-dimensional view as shown in FIG. 10 is used as a flaw detection image, it may be difficult for an operator to evaluate a defect. Therefore, each echo height is set to the XY plane,
It is also possible to create three images created by projecting onto the YZ plane and the ZX plane, respectively. Further, flaw detection image creating means 5
Reference numeral 5 may be such that only the defect is plotted based on the defect identification result.

The flaw detection image created in this way is displayed on the display device 60 (S7). The operator operates the display device 6
While checking the flaw detection image displayed at 0, it is checked whether or not there is a defect, and if a defect has occurred, whether or not the defect is acceptable. Then, the operator finally determines whether or not the inspection object 2 is acceptable. Thus, the processing flow of FIG. 7 ends.

By the way, the present inventor produced a plurality of test specimens, and conducted an experiment for detecting defects using the ultrasonic test equipment of the present embodiment and the conventional ultrasonic test equipment for these test specimens. . FIG. 11A is a diagram showing an experimental result when using the conventional ultrasonic flaw detector, and FIG. 11B is a diagram showing an experimental result when using the ultrasonic flaw detector of the present embodiment. In FIGS. 11 (a) and 11 (b), a dotted line indicates a groove.

In FIGS. 11A and 11B, the vertical axis represents depth (Z-direction position), and the horizontal axis represents axis position (Y-direction position). However, the position of the origin of the coordinate system differs between FIGS. 11A and 11B. When a conventional ultrasonic flaw detector is used, the position of the welding line estimated from a predetermined reference position on the guide rail 21 is set as the origin of the Y direction position, and the reference position on the guide rail 21 is set as the origin of the Z direction position. YZ coordinate system is used. Therefore, in the conventional ultrasonic flaw detector, the position of the welding line is assumed, and the detected echo position is
A flaw detection image is created by plotting the position relative to the welding line. On the other hand, when the ultrasonic flaw detector of the present embodiment is used, as described above, the back wave echo position is obtained from the waveform data, and the YZ reference coordinate system having the back wave echo position as the origin is adopted.

In this experiment, each test piece having one large defect was manufactured. That is, in the test body used here, the echo height of the defect echo is larger than the echo height of the back-wave echo. Further, the positions of the defects in each specimen are different from each other.

The present inventors conducted experiments as follows. First, flaw detection of a weld is performed on each specimen to detect an echo position. The area of the defect candidate can be known from the information of the echo position. Next, among the plurality of echoes in the region of the defect candidate having the spread, the one having the maximum echo height is specified. In practice, it is desirable to directly specify a defect as a region. However, in this case, the position of the echo having the maximum echo height (maximum echo position) is included in the test object in order to simplify the processing. The defect candidate is specified as a representative position. Then, the maximum echo position is plotted in a predetermined YZ coordinate system. Therefore, one point is plotted for each specimen. By performing this for all the specimens, a graph as shown in FIG. 11 is obtained. In FIG. 11,
For the sake of simplicity, the echo reflected once is ignored, and only the direct echo is shown.

According to the experimental results shown in FIG. 11, the distribution of the maximum echo position distribution is greater when the ultrasonic inspection device of this embodiment is used than when the conventional ultrasonic inspection device is used. It can be seen that the size is small, and almost all of them are contained in the welded portion 4. Specifically, the distribution of the maximum echo position in the depth direction does not change much between FIG. 11A and FIG. 11B. However, the distribution of the maximum echo position in the axial direction is from −8 mm to +3 in FIG.
In contrast to FIG. 11B, the range extends from 0 mm to 8 mm. As described above, when the conventional ultrasonic flaw detector is used, the distribution of the maximum echo position greatly varies in the Y direction.

The ultrasonic flaw detector performs flaw identification of each specimen based on the result.
In the case of (a), it is very difficult to judge the acceptability of the test object because the maximum echo position varies greatly. For example, the ultrasonic flaw detector is based on the assumed position of the back wave as shown in FIG. 11, since the back wave also has a certain width,
A range of, for example, 3 mm vertically, horizontally, and centering on the assumed position of the back wave is considered as a range where the back wave exists. At this time, the echo within the range where the back wave exists is determined to be the back wave echo, and only the echo outside the range where the back wave exists and existing in the welded portion 4 is determined to be the defect echo. By judging, a significant number of test specimens are non-defective and good. As described above, when the conventional ultrasonic flaw detector is used, defects cannot be accurately identified.

On the other hand, in the case of FIG. 11B, almost all test specimens are determined by determining that the echo present on the probe 10 side from the assumed back wave position is a defective echo. Can be determined to be defective. Therefore, the ultrasonic flaw detector according to the present embodiment can identify defects with higher accuracy than the conventional one.

When identifying a defect, information on the absolute position of the defect is not very important. This is because even if the absolute position of the defect can be known, the accuracy of the defect determination cannot be improved unless the presence or absence of the defect as a premise is accurately determined.

In the ultrasonic flaw detector of this embodiment, the back wave echo detecting means uses the result obtained by the peak detecting means to determine the peak having the maximum echo height on the YZ plane at each X-direction position. Is determined, and based on the echo position corresponding to the determined peak, the back-wave echo position in the cross section is specified.
A reference coordinate system having the origin at the back wave echo position is set for each plane, and each echo position obtained by the peak detecting means is represented by position coordinates in the reference coordinate system, and the echo position represented using the reference coordinate system Is included in a predetermined range, the echo is identified as a defective echo. Thus, even if there is a mounting error of the guide rail, a variation in the width of the extra bank, a deviation in the refraction angle, and the like, it is possible to identify with high accuracy whether or not the defect is a defect.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the invention.

In the above embodiment, a case will be described in which the probe is arranged on the side of the wide margin in the V-shaped groove, and the back-wave echo detecting means detects the position of the shape echo in the narrow margin. However, conversely, the probe may be arranged on the side of the narrow margin to detect the position of the shape echo in the wide margin. In general, the back-wave echo detection means may detect the position of the shape echo in the excess of the welded portion regardless of the shape of the groove. Therefore, the defect is detected by using the ultrasonic testing device of the present embodiment not only for the inspection object having the V-shaped groove but also for the inspection object having the X-shaped groove and the I-shaped groove, for example. be able to.

In the above-described embodiment, the case where a flat inspection object is used has been described. For example, even if a cylindrical inspection object is used, the ultrasonic inspection apparatus of the present embodiment can be used to detect defects. Can be detected.

In the above embodiment, the case where the probe position, the echo position, and the like are specified in the rectangular coordinate system has been described. For example, the probe position, the echo position, and the like are specified in the cylindrical coordinate system. You may do so.

Further, the ultrasonic flaw detector according to the present invention is also applicable to a case where the position of a shape echo in an extra bank is detected to determine the quality of welding based on the presence or absence of the extra bank, the shape of the extra bank, and the like. can do. For example, in the above-described embodiment, the presence or absence of a margin can be known by finding a back squiggly line with the back squash echo detection means and examining the echo height at each position in the X direction of the back squiggle line. If it is required that the overfill is formed firmly in order to ensure the strength of the welded portion, the quality of the welding can be determined by examining the presence or absence of such overfill. Further, the shape of the back squiggly line is checked, and for example, when the back squiggly line meanders, it can be determined that the welding is defective.

[0057]

As described above, according to the ultrasonic flaw detector of the present invention, the second processing means uses the result obtained by the first processing means to measure the echo height in each section perpendicular to the welding line. Is determined, the position of the shape echo from the welded portion in the cross section is specified based on the position of the reflection source corresponding to the obtained peak, and the defect identification means determines each cross section perpendicular to the welding line. A coordinate system with the origin of the position of the shape echo specified by the second processing means is set for each, the position of each reflection source determined by the first processing means is represented by position coordinates in the coordinate system, and the coordinate system When the position of the reflection source represented by using is included within a predetermined range, the reflection source is identified as a defect. Thus, even if there is a mounting error of the scanning unit, a variation in the width of the extra bank, a deviation in the refraction angle, etc., it is possible to identify with high accuracy whether or not the defect is a defect.

Further, in the ultrasonic flaw detector according to the present invention, the second processing means specifies the position of the shape echo from the welded portion to check for the presence or absence of a margin and the shape of the back wavy line, and to perform welding based on this. Can be determined.

[Brief description of the drawings]

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

FIG. 2 is a schematic plan view of a scanning device in the ultrasonic flaw detector.

FIG. 3 is a diagram for explaining how to scan a probe in the ultrasonic flaw detector.

FIG. 4 is a diagram for explaining a recording range of data received by the probe.

5A is a diagram showing an example of waveform data, and FIG. 5B is a diagram for explaining a process of obtaining an echo position from the waveform data.

FIG. 6 is a diagram for explaining a delayed echo.

FIG. 7 is a flowchart for explaining a processing procedure of waveform data in the ultrasonic inspection equipment of the present embodiment.

FIG. 8 is a diagram for explaining a method of detecting a back wave echo position.

FIG. 9 is a diagram for explaining a defect identification range.

FIG. 10 is a diagram for explaining a method of creating a flaw detection image.

FIG. 11A is a diagram showing an experimental result when a conventional ultrasonic flaw detector is used, and FIG. 11B is a diagram showing an experimental result when the ultrasonic flaw detector of the present embodiment is used.

[Explanation of symbols]

 2 Inspection object 4 Welded part 10 Probe 20 Scanning device 21 Guide rail 22 Arm part 30 A / D conversion part 40 Storage part 50 Control part 51 Peak detection means 52 Flaw detection image data creation means 53 Uranami echo detection means 54 Defect identification means 55 flaw detection image creation means 60 display device

Claims (10)

[Claims] A probe that receives an ultrasonic wave incident on the test object and receives a reflected echo reflected back from a reflection source in the test object; and a probe along a welding line of the test object. Scanning means for scanning the probe at a predetermined pitch in a direction orthogonal to the welding line at a position, and an echo height of each peak based on a reflected echo received by the probe at the time of scanning by the scanning means. And the first processing means for determining the position of the reflection source corresponding to each peak, using the result obtained in the first processing means, the peak echo height is maximum in each cross section perpendicular to the welding line And a second processing unit for specifying the position of the shape echo from the weld in the cross section based on the position of the reflection source corresponding to the obtained peak, and outputting the result obtained by the second processing unit Output means; Ultrasonic flaw detector according to claim. 2. A probe that receives an ultrasonic wave incident on an object to be inspected and receives a reflected echo reflected back from a reflection source in the object to be inspected, and a probe along a welding line of the object to be inspected. Scanning means for scanning the probe at a predetermined pitch in a direction orthogonal to the welding line at a position, and an echo height of each peak based on a reflected echo received by the probe at the time of scanning by the scanning means. And the first processing means for determining the position of the reflection source corresponding to each peak, using the result obtained in the first processing means, the peak echo height is maximum in each cross section perpendicular to the welding line Second processing means for determining the position of the shape echo from the weld in the cross section based on the position of the reflection source corresponding to the obtained peak, and the second processing means for each cross section perpendicular to the welding line Of the shape echo specified by the processing means A coordinate system with the position as the origin, the position of each reflection source determined by the first processing means is represented by position coordinates in the coordinate system, and the position of the reflection source represented using the coordinate system is A defect identification unit that identifies the reflection source as a defect when the reflection source is included in a predetermined range; and an output unit that outputs a result obtained by the defect identification unit. Ultrasonic flaw detector. 3. When the second processing means finds a peak having a maximum echo height in a cross section perpendicular to the welding line, the position of the reflection source corresponding to the found peak and the position of the reflection source adjacent to the cross section are determined. Calculate the distance between the position of the shape echo specified in the previous scan and the position projected on the cross-section at the matching cross-section, and when the calculated distance is equal to or smaller than a predetermined reference value, the position of the reflection source. Is specified as the position of the shape echo in the cross section, while, when the calculated distance is larger than the reference value, the position of the position of the shape echo specified in the previous scan is projected on the cross section, The ultrasonic flaw detector according to claim 1 or 2, wherein the position is specified as a position of the shape echo. 4. The position of the shape echo specified by the second processing means is a position of an extra welded portion formed on a side opposite to a side on which the probe scans. 4. The ultrasonic flaw detector according to 1, 2, or 3. 5. The apparatus according to claim 1, wherein a pair of said probes are arranged on both sides of said welding line.
The ultrasonic flaw detector according to 3 or 4. 6. While scanning the probe at a predetermined pitch in a direction perpendicular to the welding line at each position along the welding line of the object to be inspected, the probe moves from the probe into the object to be inspected. A first step in which a sound wave is incident, and a reflected echo reflected back from a reflection source in the object to be inspected is received by the probe, based on the reflected echo received by the probe, an echo of each peak. The second step of determining the height and the position of the reflection source corresponding to each peak, using the result obtained in the second step, the peak having the maximum echo height in each cross section perpendicular to the welding line. A third step of determining the position of the shape echo from the weld in the cross section based on the position of the reflection source corresponding to the determined peak, and outputting the result obtained in the third step to output means. A fourth step, comprising: Wave testing method. 7. While scanning the probe at a predetermined pitch in a direction orthogonal to the welding line at each position along the welding line of the object to be inspected, the probe moves from the probe into the object to be inspected. A first step in which a sound wave is incident, and a reflected echo reflected back from a reflection source in the object to be inspected is received by the probe, based on the reflected echo received by the probe, an echo of each peak. The second step of determining the height and the position of the reflection source corresponding to each peak, using the result obtained in the second step, the peak having the maximum echo height in each cross section perpendicular to the welding line. A third step of determining the position of the shape echo from the weld in the cross section based on the position of the reflection source corresponding to the obtained peak, and in the third step for each cross section perpendicular to the welding line. Set the coordinate system with the specified shape echo position as the origin. The position of each reflection source determined in the second step is represented by position coordinates in the coordinate system, and the position of the reflection source represented using the coordinate system is included in a predetermined range. An ultrasonic flaw detection method, comprising: a fourth step of sometimes identifying the reflection source as a defect; and a fifth step of outputting a result obtained in the fourth step. 8. In the third step, when a peak having a maximum echo height is obtained in a cross section perpendicular to the welding line, the position of the reflection source corresponding to the obtained peak is adjacent to the cross section. Calculate the distance between the position of the shape echo specified in the previous scan on the cross section and the position projected on the cross section, and when the calculated distance is equal to or less than a predetermined reference value, the position of the reflection source is calculated. When the calculated distance is larger than the reference value, the position where the position of the shape echo specified in the previous scan is projected on the cross section is specified as the position of the shape echo in the cross section. 8. The ultrasonic inspection method according to claim 6, wherein the position is specified as an echo position. 9. The position of the shape echo specified in the third step is a position of a margin of a welded portion formed on a side opposite to a side on which the probe scans. , 7
Or the ultrasonic flaw detection method according to 8. 10. The apparatus according to claim 6, wherein a pair of said probes are arranged on both sides of said welding line.
The ultrasonic inspection method according to 7, 8, or 9.