JP2013156166A - Ultrasonic flaw detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic flaw detection method capable of surely detecting a flaw (including penetration and excess metal) position generated on a welding portion without moving a probe by arranging the probe for oscillating an SH wave in the vicinity of the welding portion.SOLUTION: The ultrasonic flaw detection method includes the steps of: oscillating an ultrasonic wave to a cross section of a predetermined area crossing a welding portion B1 at a predetermined angle/focal depth and detecting a reflected wave; oscillating an ultrasonic wave at an angle/focal depth different from the predetermined angle/focal depth and detecting a reflected wave; and identifying a position of a flaw F by collating ultrasonic wave detection results of respectively different angle/focal depth values each other.

Description

  The present invention relates to an ultrasonic flaw detection method used for nondestructive inspection of containers, pipes and the like of plants, ships, vehicles and the like.

  Conventionally, nondestructive inspection using a transverse wave oblique angle (hereinafter referred to as an SV wave) and a longitudinal wave oblique angle has been performed for flaw detection near the weld metal portion. However, in such a flaw detection method, the weld metal part generates crystal grains of the welded portion, the bending of sound waves due to the boundary, and so on, (1) the influence of noise generated from the crystal grains, and (2) the sound wave due to the weld boundary. Due to factors such as (3) the influence of the shape (back wave, etc.), (4) the generation of mode-converted waves and secondary creeping waves caused by defects during longitudinal wave flaw detection, There was a problem that it was difficult to accurately detect and identify the defective part.

For example, as shown in FIG. 11, when a probe serving as the probe 1 is scanned by a flaw detection method using a transverse wave oblique angle (SV wave), a sound wave (indicated by the symbol W) is welded (indicated by the plate B). It is easy to bend in the growth direction of the welded portion (indicated by reference numeral B1), and is easily influenced by the shape of a back wave or the like and a pseudo signal due to welding.
In addition, as shown in FIG. 12, when scanning is performed by the probe (probe) 2 by a flaw detection method using a longitudinal wave oblique angle, a generated sound wave is a pseudo signal (indicated by this signal). It is difficult to identify the defect position by superimposing it on the defect position.

In order to solve such a problem, a flaw detection apparatus using a shear horizontal wave (horizontal wave, hereinafter referred to as SH wave) as shown in Patent Documents 1 to 3 is used.
For example, in the ultrasonic flaw detection apparatus disclosed in Patent Document 1, adhesion and contact medium film uniformity are achieved by using a sensor in which a plurality of transducers that generate shear waves of transverse waves are connected to each other by an elastic body. Improve and read adjacent transducer relative position information by strain gauge, calculate transducer drive timing using ultrasonic beam incident angle and adjacent transducer relative position information, and drive transducer by sensor deformation Timing errors are prevented.

JP 2001-305115 A JP 2009-42173 A JP 2000-146922 A

By the way, since the ultrasonic flaw detection method using SH waves is excellent in the straightness of sound waves, the influence of bending due to acoustic anisotropy is small and the reflection efficiency at the defect corner is high, but the viscosity is high. Since it is necessary to use a contact medium, there has been a problem to be solved, such as inability to measure while scanning the sensor back and forth.
Further, even in an ultrasonic flaw detection sensor with improved adhesion and uniformity of the contact medium film as shown in the cited document 1, as shown in FIG. 13, the probe 3 and the coplant 4 (contact medium) Due to the poor adhesion, there is still a problem that the scanning performance is not improved and proper flaw detection cannot be performed.

  The present invention has been made in view of the above-described circumstances, and a probe that oscillates an SH wave is arranged in the vicinity of a welded portion, and defects and backs that have occurred in the welded portion without moving the probe. An object of the present invention is to provide an ultrasonic flaw detection method capable of reliably detecting a wave and an extra-spot position over a wide range.

In order to solve the above problems, the present invention proposes the following means.
In the ultrasonic flaw detection method of the present invention, a step of oscillating ultrasonic waves at a predetermined angle with respect to a cross section of a predetermined region across the weld and detecting a reflected wave, and oscillating ultrasonic waves at an angle different from the angle. And a step of detecting a reflected wave and a step of discriminating a defect position by collating ultrasonic detection results at the different angles.

  Further, in the ultrasonic flaw detection method of the present invention, a step of oscillating ultrasonic waves at a predetermined focal depth with respect to a cross section of a predetermined region across the weld and detecting a reflected wave, and a focal depth different from the focal depth. Then, the method includes a step of oscillating an ultrasonic wave and detecting a reflected wave, and a step of discriminating a defect position by collating ultrasonic detection results at the different focal depths.

  In the ultrasonic flaw detection method of the present invention, an ultrasonic wave is oscillated at a predetermined angle and a focal depth with respect to a cross section of a predetermined region across the welded portion, and a reflected wave is detected, and the angle and the focal depth are detected. Oscillating ultrasonic waves at different angles and focal depths to detect reflected waves, and identifying defect positions by collating ultrasonic detection results at the different angles and focal depths. It is characterized by having.

  In the ultrasonic flaw detection method described above, an ultrasonic wave is oscillated at a predetermined angle / focus depth with respect to a cross section of a predetermined region straddling the welded portion, and a reflected wave is detected, and is different from these angles / focus depths. After oscillating ultrasonic waves at an angle / focus depth and detecting a reflected wave, the defect position is determined by collating the ultrasonic detection results at different angles / focus depths. As a result, it is possible to reliably detect defects, back waves, and surplus positions that occur in the welded part without moving the probe that oscillates the SH wave, as in the past. It can be carried out.

In the ultrasonic flaw detection method of the present invention, the probe that oscillates the ultrasonic wave is a phased array ultrasonic flaw detection probe in which a plurality of transducers that emit SH waves are arranged.
In the ultrasonic flaw detection method of the present invention, the probe that oscillates the ultrasonic wave performs a linear scan that oscillates the ultrasonic wave in a row at a constant interval.

  In the ultrasonic flaw detection method of the present invention, the probe that oscillates the ultrasonic wave performs sector scan that oscillates the ultrasonic wave in a fan-like manner at regular intervals.

  In the ultrasonic flaw detection method described above, the probe that oscillates the ultrasonic wave is a phased array ultrasonic flaw detection probe in which a plurality of transducers are arranged, and the probe is arranged at regular intervals. By performing a linear scan that oscillates an ultrasonic wave in a shape or by performing a sector scan that oscillates an ultrasonic wave at a certain interval, a defect can be detected over a certain wide range of a weld.

  In the ultrasonic flaw detection method of the present invention, in the step of determining the defect position, the scan data obtained by the scan is analyzed by superimposing the shape image of the welded portion.

  In the ultrasonic flaw detection method of the present invention, the defect range is specified together with the position of the defect based on the result of the analysis.

  Then, in the ultrasonic flaw detection method described above, in the step of determining the defect position, the scan data obtained by a plurality of scans are analyzed by superimposing the shape image of the weld, so that the defect of the weld is detected. The length and range of the defect can be specified together with the position, and the subsequent maintenance can be performed efficiently.

  According to the ultrasonic flaw detection method according to the present invention, an ultrasonic wave is oscillated at a predetermined angle / focus depth with respect to a cross section of a predetermined region straddling the welded portion, a reflected wave is detected, and these angles / focus depths are detected. After detecting ultrasonic waves at different angles / focus depths and detecting reflected waves, the defect positions are determined by comparing the ultrasonic detection results at different angles / focus depths. As a result, it is possible to reliably detect defects, back waves, and surplus positions that occur in the welded part without moving the probe that oscillates the SH wave, as in the past. It can be carried out.

It is a flowchart about the ultrasonic flaw detection method (identification of a back wave shape and a defect) which concerns on 1st Embodiment. It is explanatory drawing which concerns on the linear scan flaw detection based on the flowchart of FIG. It is a flowchart about the ultrasonic flaw detection method (surface shape and defect identification) which concerns on 1st Embodiment. It is explanatory drawing which concerns on the linear scan flaw detection which concerns on the flowchart of FIG. It is a figure which shows the example at the time of setting the focal depth to the back surface of a welding part regarding the ultrasonic flaw detection method which concerns on 2nd Embodiment, Comprising: (A) is a figure which shows the scanning state for every sector, (B) FIG. 4 is a diagram showing a scan state of the entire sector. It is a figure which shows the example at the time of setting the focal depth to the surface of a welding part regarding the ultrasonic flaw detection method which concerns on 2nd Embodiment, Comprising: (A) is a figure which shows the scanning state for every sector, (B) FIG. 4 is a diagram showing a scan state of the entire sector. It is a flowchart about the ultrasonic flaw detection method which concerns on 3rd Embodiment. It is explanatory drawing which concerns on the linear scan flaw detection which concerns on the flowchart of FIG. It is a flowchart about the ultrasonic flaw detection method which concerns on 4th Embodiment. It is explanatory drawing which concerns on the linear scan flaw detection which concerns on the flowchart of FIG. It is explanatory drawing which shows the conventional ultrasonic testing method (1). It is explanatory drawing which shows the ultrasonic flaw detection method (2) based on the past. It is explanatory drawing which shows the ultrasonic flaw detection method (3) based on the past.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a flowchart related to “identification of back wave shape and defect”, and FIG. 2 is an explanatory diagram related to linear scan flaw detection according to the flowchart of FIG. 1. FIG. 3 is a flowchart related to “identification of surface shape and defect”, and FIG. 4 is an explanatory diagram related to linear scan flaw detection according to the flowchart of FIG. 3.

In the first embodiment, using a phased array ultrasonic flaw detector in which a plurality of probes that oscillate ultrasonic waves are arranged, a cross section of a region straddling the welded portion B1 and welded portion B of the plate B to be inspected Flaw detection by linear scanning at a predetermined angle.
At this time, in the phased array ultrasonic flaw detector, the defect inspection of the welded portion B1 is performed using the transverse wave flaw detection (SV) and the longitudinal wave flaw detection as a previous step. Then, utilizing the characteristics of the transverse wave SH wave (the influence of bending due to acoustic anisotropy is small and the reflection efficiency at the defect corner is high) at the position where the abnormal signal is detected by transverse wave flaw detection (SV) or longitudinal wave flaw detection. Using the SH wave phased array, electronic scanning (linear scanning, sector scanning) is performed without moving the probe, thereby carrying out more precise flaw detection.

  Further, in the flaw detection using the SH wave according to the first embodiment, after electronic scanning is performed at a plurality of refraction angles (for example, α = 45 ° and 60 °), electronic scan data that is a scan result, and the groove of the welded portion By combining the shape with the shape on the screen, the reflection source indicating the defect position is specified. In addition, although the SH wave is excellent in straightness and has few pseudo signals, the 45 ° refraction angle is easily affected by the shape of the back wave and the surplus, and is easily detected as a pseudo signal. Further, the refraction angle of 60 ° is not easily affected by the shape of the back wave and the surplus. By utilizing the characteristics of these angles, it is possible to confirm the relative positional relationship between the back wave / excess position and the defect position.

Hereinafter, the step (SP) of the flowchart according to “Identification of Back Wave Shape and Defect” in FIG. 1 will be described with reference to FIG.
[Steps 1-2]
A transverse wave flaw (SV) and a longitudinal wave flaw detection are performed on the welded part B1 to be inspected, and detection signals thereof are received.
[Step 3]
45 ° and 60 ° outputted from the probe 10 (see FIG. 2) of the phased array ultrasonic flaw detector for the lower region and the back surface of the weld B1 in which defects are suspected based on the flaw detection result in Step 1. A linear scan is performed by each SH-PA wave, and the reflected wave reflected by the flaw detection (indicated by the symbol WA) is received by the probe 10. Note that the linear scan here is pre-adjusted so that the focal depth matches the back surface of the weld B1.

[Step 4]
It is determined whether or not the ultrasonic signal subjected to the linear scan by the SH wave in step 3 is reflected by the defect or the back wave and returned as the reflected wave WA. (Step 4A), the process proceeds to the next Step 5 if the reflected wave is YES.

[Step 5]
As shown in FIG. 2, the position of the defect or the back wave is obtained by superimposing the linear scan data by the SH-PA wave at 45 ° or 60 ° performed in step 3 and the shape data indicating the weld B1. Identify.
Specifically, in the upper left side of FIG. 2, when a linear scan is performed with a 45 ° SH wave, there is a convex back wave (indicated by symbol M) on the back surface, and a defect (reference symbol) is present in the weld B1. A detection example of the presence of F) is shown. Further, the upper right side of FIG. 2 shows that when linear scanning is performed with a 60 ° SH wave, the convex back wave on the back surface is not detected, and the weld B1 has a defect (indicated by reference numeral F). An example of detection is shown.
In Step 5, it is determined whether a reflected wave of 45 ° SH wave or a reflected wave of 60 ° SH wave is detected, and only a reflected wave of 45 ° SH wave is detected. If the reflected wave of both 45 ° and 60 ° SH waves is detected, the flow proceeds to steps 8-9.

[Steps 6-7]
As shown in the upper left side of FIG. 2, by overlapping the linear scan data by the SH wave at 45 ° and the shape data indicating the welded portion B1, a convex backwave M on the back surface of the welded portion B1, and It can be detected that there is a defect F in the weld B1.

[Steps 8-9]
As shown in the lower part of FIG. 2, the linear scan data by the SH waves at 45 ° and 60 ° and the shape data indicating the welded portion B1 are overlapped to form a convex backwave M on the back surface of the welded portion B1. It can be clearly identified that there is a defect F in the weld B1.

  Then, by sequentially performing the steps shown in FIG. 1 and FIG. 2, it becomes possible to detect the defect F and the back wave M, respectively, with respect to the lower region and the surface of the weld B1 in which the existence of the defect is suspected. .

Hereinafter, steps of the flowchart according to “Identification of Surface Shape and Defect” in FIG. 3 will be described with reference to FIG.
The identification processing of FIGS. 3 and 4 shares most of the processing contents with FIGS. 1 and 2, and the difference (step 3 ′) will be described below.

  1 and 2, the output of the ultrasonic wave is adjusted so that the SH wave has the focal depth coincident with the back surface of the welded part B1 of the plate body B, thereby causing defects in the welded part B1 (mainly the lower region). Alternatively, the position of the back wave is specified. On the other hand, in FIGS. 3 and 4, the output of the ultrasonic wave is adjusted so that the SH wave is reflected on the back surface of the welded portion B1 of the plate body B and the focal depth matches the surface of the welded portion B1. Thus, the position of the defect (mainly the upper region) or the surplus of the surface (indicated by the symbol N) of the weld B1 is specified.

[Step 3 ']
45 ° and 60 ° output from the probe 10 of the phased array ultrasonic flaw detector (see FIG. 4) with respect to the upper region and surface of the weld B1 suspected of the presence of defects based on the flaw detection results in Step 1. A linear scan is performed by each SH-PA wave, and the probe 10 receives a reflected signal from the flaw detection. The linear scan here is adjusted so that the focal depth matches the surface of the weld B1. Thereafter, in step 4, it is determined whether or not the ultrasonic signal that has been linearly scanned by the SH wave in step 3 ′ is reflected on the upper region or surface of the weld B1 and returned as a reflected wave. If NO, there is no reflected wave, it is determined as “sound”, and if YES, the process proceeds to the next step 5.

  Then, by sequentially performing the steps shown in FIGS. 3 and 4, it becomes possible to detect the defect F and the surplus N, respectively, with respect to the upper region and the surface of the welded portion B1 where the existence of the defect is suspected. .

  As described in detail above, in the ultrasonic flaw detection method shown in the first embodiment, linear at a predetermined angle (45 ° in this example) with respect to a cross section of a predetermined region straddling the welded portion B1 of the plate body B. An ultrasonic wave for scanning is oscillated to detect a reflected wave. Further, after detecting an reflected wave by oscillating an ultrasonic wave for performing linear scanning at an angle different from the angle (60 ° in this example), the ultrasonic detection results at these different angles (45 ° and 60 °). The defect F (including the back wave N and the surplus M) is discriminated by comparing the reflected wave of the ultrasonic wave. As a result, the position of the defect F (including the back wave N and the surplus M) generated in the welded portion B1 can be reliably detected without moving the probe that oscillates the SH wave as in the prior art. .

In the above embodiment, the ultrasonic oscillation angles from the probe 10 of the phased array ultrasonic flaw detector are 45 ° and 60 °, but the present invention is not limited to this. Further, instead of two kinds of ultrasonic oscillation angles, ultrasonic waves may be oscillated at three or more kinds of angles, and each reflected wave may be collated with the shape of the welded portion B1 of the plate B.
Further, Steps 6 and 7 in FIGS. 2 and 4 may be omitted as appropriate for speeding up the processing, and all defects F, back waves N, and surplus M may be determined only in Steps 8 and 9.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS.
In the second embodiment shown in FIGS. 5 and 6, a phased array ultrasonic flaw detector in which a plurality of probes that oscillate ultrasonic waves are arranged, a welded portion B1 of a plate B to be inspected, and Flaw detection is performed on the region straddling the welded portion B by a sector scan at a predetermined angle.
In the second embodiment, basically the same processing as the flowchart of the first embodiment is performed, except that the form of the ultrasonic wave output from the transducer of the phased array ultrasonic flaw detector is different.

  In the sector scan of the second embodiment, in FIG. 5, the output angles of the SH-PA waves from the respective transducers are all 45 °, and ultrasonic waves are output at regular intervals. By such sector scan, as shown in FIGS. 5A and 5B, a larger scan area than the linear scan shown in FIGS. 1 and 2 can be secured.

  Further, the sector scan in FIG. 5 is adjusted so that the focal depth coincides with the back surface of the welded portion B1, thereby identifying the position of the defect F (mainly the lower region) of the welded portion B1. Yes. Note that the position of the defect F in the welded portion B1 here is the same as the processing described in step 5 of the flowchart of FIG. 2, sector scan data by SH-PA waves at an output angle of 45 °, and the welded portion B1. The position of the defect F (mainly the lower region) is specified by superimposing the shape data indicating the above.

  On the other hand, in the sector-like sector scan shown in FIG. 6, the output angles of the SH-PA waves from each transducer are all set to 60 ° so that the angles are different from those in FIG. Output sound waves. By such sector scanning, as shown in FIGS. 6A and 6B, a larger scanning area than the linear scanning shown in FIGS. 1 and 2 can be similarly secured.

On the other hand, the sector scan shown in FIG. 6 is adjusted so that the focal depth coincides with the surface of the welded portion B1, thereby identifying the position of the defect F (mainly the upper region) of the welded portion B1. ing.
Note that the position of the defect F in the welded part B1 here is the same as the process described in step 5 of the flowchart of FIG. 2 by using sector scan data by SH-PA waves at an output angle of 60 ° and the welded part B1. By superimposing the shape data shown, the position of the defect F (mainly the lower region) is specified.

  Furthermore, if the sector scan data by the SH waves at 45 ° and 60 ° and the shape data indicating the welded portion B1 are overlapped, whether or not there is a defect F in the entire vertical range of the welded portion B1. Judgment can be made.

  As described above in detail, in the ultrasonic flaw detection method shown in the third embodiment, a sector is formed at a predetermined angle (45 ° in this example) with respect to a cross section of a predetermined region straddling the welded portion B1 of the plate body B. An ultrasonic wave for scanning is oscillated to detect a reflected wave. Further, after detecting the reflected wave by oscillating an ultrasonic wave for performing sector scanning at an angle different from the angle (60 ° in this example), the ultrasonic detection results (45 ° and 60 ° at these different angles) are detected. The defect F of the weld B1 is discriminated by checking the reflected wave of the ultrasonic wave at °. Thereby, the defect F generated in the welded portion B1 can be reliably detected in a wide range without moving the probe that oscillates the SH wave as in the conventional case.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIGS.
FIG. 7 is a flowchart relating to “identification of defects on the back side of the welded portion B1”, and FIG. 8 is an explanatory diagram relating to scan flaw detection according to the flowchart of FIG.
In the third embodiment shown in FIGS. 7 and 8, using a phased array ultrasonic flaw detector in which a plurality of probes that oscillate ultrasonic waves are arranged, a welded portion B1 of a plate B to be inspected and The flaw detection is performed by linear scanning at a plurality of focal depths on the cross section of the region straddling the weld B.

Hereinafter, the flowchart of FIG. 7 will be described for each step (SP).
[Step 10]
A transverse wave flaw (SV) and a longitudinal wave flaw detection are performed on the welded part B1 to be inspected, and detection signals thereof are received.

[Step 11]
Based on the flaw detection result in step 10, the focal depth output from the probe 10 of the phased array ultrasonic flaw detector (see FIG. 8A) for the lower region and the back surface of the weld B1 where the existence of a defect is suspected. A linear scan is performed by a plurality of SH-PA waves whose phases are changed in stages, and the reflected wave WA due to the flaw detection is received by the probe 10. The linear scan here can detect the range of the defect F of the weld B1 by sequentially changing the focal depth of the ultrasonic signals output from the plurality of probes 10 for each scan. To do. Further, in FIG. 7, the linear scan here sets the refraction angle from the probe 10 to the welded portion B1 at 45 °, but this can be changed stepwise.

[Step 12]
It is determined whether or not the ultrasonic signal that has been linearly scanned by the plurality of SH waves in step 11 is reflected by a defect or a back wave and returned as a reflected wave. Based on the reflected wave of the depth, the position of the defect F is specified as shown in FIG.

[Step 13]
As shown in FIG. 8C, the position of the defect F on the weld B1 is specified by superimposing the scan data obtained in Step 12 and the shape data indicating the weld B1.

As described above in detail, in the ultrasonic flaw detection method shown in the third embodiment, ultrasonic waves having various focal depths are oscillated with respect to a cross section of a predetermined region straddling the welded portion B1 of the plate body B. A linear scan was performed, and the position of the defect F on the weld B1 was specified by superimposing the scan result with the shape data indicating the weld B1. As a result, the position of the defect F generated in the welded portion B1 can be reliably detected without moving the probe that oscillates the SH wave as in the prior art, and the data and the groove with variable focal depth can be detected. The end position (indicated by reference numeral F1) and the range of the defect F can be evaluated by matching the shape, and the sizing accuracy of the defect height can be improved.
In the linear scan, the defect F generated in the weld B1 can be detected with higher accuracy by changing the refraction angle from the probe 10 to the weld B1 stepwise.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIGS.
FIG. 9 is a flowchart relating to “identification of defects on the back side of the welded portion B1”, and FIG. 10 is an explanatory diagram relating to scan flaw detection according to the flowchart of FIG.
In the third embodiment shown in FIG. 9 and FIG. 10, a phased array ultrasonic flaw detector in which a plurality of transducers are arranged as a probe that oscillates an ultrasonic wave is used to detect the plate B to be inspected. A flaw detection is performed by a sector scan at a predetermined angle with respect to the welded portion B1 and the region straddling the welded portion B.

The flowchart of FIG. 9 will be described below for each step (SP).
[Step 20]
A transverse wave flaw (SV) and a longitudinal wave flaw detection are performed on the welded part B1 to be inspected, and detection signals thereof are received.

[Step 21]
Based on the flaw detection result in step 20, the depth of focus output from the probe 10 of the phased array ultrasonic flaw detector (see FIG. 10A) for the lower region and the back surface of the weld B1 suspected of having a defect. A sector-like sector scan is performed using a plurality of SH-PA waves whose phases are changed in stages, and the reflected wave WA due to these flaws is received by the probe 10. By such sector scan, as shown in FIG. 10B, a larger scan area than the linear scan of the third embodiment can be secured.

  The sector scan here can detect the defect F of the welded portion B1 in a wide range by sequentially changing the focal depth of the ultrasonic signals output from the plurality of probes 10 for each scan. To do. In FIG. 9, the sector scan here sets the refraction angle from the probe 10 to the welded portion B1 at 45 °, but this can be changed stepwise.

[Step 22]
It is determined whether or not the ultrasonic signal that has been sector-scanned by the plurality of SH waves in step 21 is reflected by a defect or a back wave and returned as a reflected wave. Based on the reflected wave of the depth, the position of the defect F is specified as shown in FIG.

[Step 23]
As shown in FIG. 10C, the position of the defect F on the welded portion B1 is specified by superimposing the scan data obtained in step 22 and the shape data indicating the welded portion B1.

As described above in detail, in the ultrasonic flaw detection method shown in the third embodiment, ultrasonic waves having various focal depths are oscillated with respect to a cross section of a predetermined region straddling the welded portion B1 of the plate body B. Then, a sector-like sector scan was performed, and the position of the defect F on the welded part B1 was specified by superimposing the scan result on the shape data indicating the welded part B1. As a result, the position of the defect F generated in the welded portion B1 can be reliably detected without moving the probe that oscillates the SH wave as in the prior art, and the data and the groove with variable focal depth can be detected. The end position (indicated by reference numeral F1) and the range of the defect F can be evaluated by matching the shape, and the sizing accuracy of the defect height can be improved.
Moreover, in the fan-shaped sector scan, the defect F generated in the welded portion B1 can be detected with higher accuracy by changing the refraction angle from the probe 10 to the welded portion B1 stepwise.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

The present invention relates to an ultrasonic flaw detection method used for nondestructive inspection of containers, pipes and the like of plants, ships, vehicles and the like.

10 Probe B1 Weld F Defect M Back wave (Defect)
N extra (defect)

Claims (8)

Oscillating an ultrasonic wave at a predetermined angle with respect to a cross section of a predetermined region straddling the weld, and detecting a reflected wave;
Oscillating ultrasonic waves at an angle different from the angle and detecting reflected waves; and
A step of discriminating a defect position by collating ultrasonic detection results at the different angles. Oscillating an ultrasonic wave at a predetermined focal depth with respect to a cross section of a predetermined region across the weld, and detecting a reflected wave;
Oscillating ultrasonic waves at a focal depth different from the focal depth and detecting reflected waves;
And a step of discriminating a defect position by collating ultrasonic detection results at the different focal depths. Oscillating ultrasonic waves at a predetermined angle and depth of focus with respect to a cross section of a predetermined region across the weld, and detecting reflected waves;
Oscillating an ultrasonic wave at an angle and a focal depth different from the angle and the focal depth, and detecting a reflected wave;
A step of discriminating a defect position by collating ultrasonic detection results at different angles and focal depths.   The ultrasonic wave according to any one of claims 1 to 3, wherein the probe that oscillates the ultrasonic wave is a phased array ultrasonic flaw detection probe in which a plurality of transducers that emit SH waves are arranged. Flaw detection method.   5. The ultrasonic flaw detection according to claim 1, wherein the probe that oscillates ultrasonic waves performs a linear scan that oscillates ultrasonic waves in rows at regular intervals. 6. Method.   5. The ultrasonic flaw detection method according to claim 1, wherein the probe that oscillates the ultrasonic wave performs sector scan that oscillates the ultrasonic wave in a fan-like manner at regular intervals. .   7. The analysis according to claim 1, wherein in the step of determining the defect position, analysis is performed by superimposing scan data obtained by the scan with a shape image of the weld. Ultrasonic flaw detection method.   The ultrasonic flaw detection method according to claim 7, wherein a range of the defect is specified together with a position of the defect based on a result of the analysis.

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