JP4527216B2 - Ultrasonic flaw detection method and ultrasonic flaw detection apparatus - Google Patents

Description

【００４９】
６４個のエレメントの内、ＰＡ法として使用するのは６２エレメントであり、残り２個のエレメント（番号６３、６４）は、ダミーとする。これは番号６３、６４のエレメント用のチャンネルをＴＯＦＤ−１、ＴＯＦＤ−２用に利用するためである。
【００５０】
表１に示されるように、ＰＡ法用の探触部の６４エレメント中、６２エレメントにチャンネル番号として図３の左端のエレメントより１〜６２の番号を割り当てる。
【００５１】
ＣＯＮＦＩＧＵＲＡＴＩＯＮ Ｎｏ．１〜３３の内１ケースと、ＣＯＮＦＩＧＵＲＡＴＩＯＮ Ｎｏ．３４、３５（ＴＯＦＤ−１、ＴＯＦＤ−２）を同時励振可能とする。ＣＯＮＦＩＧＵＲＡＴＩＯＮ Ｎｏ．１〜３３の切り替えは、電子的に瞬時（１ナノ秒の単位）に行われる。
【００５２】
以上のようにして、本形態においては、ＰＡ法によりアレイプローブ２１を用いて肉盛り溶接部１１に対する超音波探傷が行われ、ＴＯＦＤ法により２対の送信探触子３１Ｔ、３２Ｔ及び受信探触子３１Ｒ、３２Ｒを用いて母材溶接部１２に対する超音波探傷が肉盛り溶接部１１の超音波探傷と同時に行われる。
【００５３】
なお、上記の形態においては、アレイプローブ２１におけるエレメント数が６４個の場合について説明したが、エレメントの数は６４に限定されないことは言うまでもない。
【００５４】
以上の点をまとめると、上記実施例の効果としては、以下のような点があげられる。
１．ＴＯＦＤ法とＰＡ法を併用（同時深傷）した自動超音波深傷装置により、クラッド鋼製圧力容器、及びステンレス／インコネル等の内面肉盛り溶接仕様の圧力容器の溶接継ぎ手部の傷検出／合否判定検査が、母材溶接部に限らず、肉盛り溶接部も可能となった。
【００５５】
２．ＴＯＦＤ法とＰＡ法の併用（同時深傷）により、傷の検出／サイジングのみならず、傷の性状判別も含めた精度の高い探傷が可能となった。
【００５６】
３．ＴＯＦＤ法／ＰＡ法の併用システムのデータ入手に要する検査時間は、ＴＯＦＤ法のみのシステムと同じであり極めて速い。放射線検査（ＲＴ）に比較すると検査費用の大幅なコストダウンにつながる。
【００５７】
４．圧力容器の溶接後熱処理（ＰＷＨＴ）後のステージで放射線検査（ＲＴ）要という要求が多くなってきている。このような要求に対して、板厚４インチ以下の場合、コード上放射線検査（ＲＴ）をＰＷＨＴ後に実施しなければならない。従来はＰＷＨＴ前後に品質確認のため、放射線検査（ＲＴ）を計２回実施していた。これに対し、ＰＷＨＴ前は、上記実施例による自動超音波深傷装置にて、母材溶接部／肉盛り溶接部の健全性を確認し、放射線検査（ＲＴ）は、ＰＷＨＴ後のみ実施することが可能となる。これにより検査費用の大幅なコストダウンにつながる。
【００５８】
【発明の効果】
以上説明してきたように、本発明によれば、ＴＯＦＤ法とＰＡ法という異なる二種類の超音波深傷を、単一の超音波深傷スキャナを用いて、一回の探傷時に同時に行うことにより、検査時間の短縮された精度の高い超音波探傷が可能となった。
【図面の簡単な説明】
【図１】本発明において用いられるＰｈａｓｅｄ Ａｒｒａｙ法による超音波探傷を説明するための図である。
【図２】図１におけるＰｈａｓｅｄ Ａｒｒａｙ法において用いられる超音波探傷用のアレイプローブとＴＯＦＤ法において用いられる第２の探触部の関係を上方から見て示した図である。
【図３】図１におけるアレイプローブの動作を説明するための図である。
【図４】図３のアレイプローブにより実現される電子レンズの機能を模式的に示した図である。
【符号の説明】
１０ 溶接継ぎ手部
１１ 肉盛り溶接部
１２ 母材溶接部
２０ 第１の探触部
２１ アレイプローブ
２２ 励振パルス遅延回路
３０ 第２の探触部
３１Ｔ、３２Ｔ 送信探触子
３１Ｒ、３２Ｒ 受信探触子[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic flaw detection method and an ultrasonic flaw detection apparatus for a welded joint portion of a pressure vessel made of clad steel and a pressure vessel such as stainless steel / Inconel with an internal overlay welding specification.
[0002]
[Prior art]
The ASME code that prescribes the design, manufacture, and inspection of pressure vessels, as well as other national and international regulations / codes, were premised on radiation inspection (RT). However, as ultrasonic inspection (UT) is widely used in nuclear power equipment, an exception has been introduced that automatic ultrasonic inspection (AUT) may be used as an alternative to radiation inspection (RT) around 1994. There was a move to enact.
[0003]
Later, after the deliberation of the ASME Standards Committee, on December 23, 1996, an exception rule was approved as ASME CODE CASE 2235, and it was possible to perform pass / fail judgment inspection of pressure vessels with a thickness of 4 inches or more using an automatic ultrasonic flaw detector. became.
[0004]
The basic requirements of ASME CODE CASE 2235 include:
[0005]
1. Applies to plate thickness of 4 inches or more.
2. Detect the 2 inch area on either side of the weld line.
3. Performs automatic data processing by computer.
4). The inspection result also saves the original data as a file.
5. Prepare a test specimen for accreditation containing a flaw including a flaw having a size not exceeding 0.06 t.
6). 6. Inspector certification Evaluation approval by demonstration of inspection method 8. 8. Measurement of scratch dimensions (S: depth position, L: length, A or 2A: height) Submission of inspection records10. Pass / Fail Judgment Criteria The ASME CODE CASE 2235 pass / fail judgment criteria determine the aspect ratio by measuring the depth (A or 2A) and length (L) of the flaw, and the allowable flaw length determined according to the aspect ratio. The pass / fail is determined by (L). Therefore, in order to apply ASMECODE CASE 2235, accurate measurement of the depth position, length and height of the wound is required.
[0006]
In response to such demands, among the ultrasonic flaw detection methods, in particular, TOFD (Time of Flight Diffraction) that can measure the height of the flaws more accurately than other ultrasonic nondestructive inspection methods. Method) is adopted.
[0007]
Applying the TOFD method throughout inspection, installation, and maintenance during the production of the pressure vessel can help to monitor and maintain the integrity of the pressure vessel. With the spread of Risk Based Inspection, in-use inspection and remaining life diagnosis by the TOFD method are performed.
[0008]
The TOFD method is disclosed, for example, as “TOFD New Ultrasonic Flaw Detection Method and Its Utilization” in a separate volume of the September 1998 issue of “Welding Technology”. In simple terms, the TOFD method arranges a transmitting probe and a receiving probe facing each other, propagates longitudinal waves from the transmitting probe, and generates diffracted waves generated at the upper and lower ends of the existing flaws. Is received and analyzed by the receiving probe.
[0009]
The depth and height of the flaw can be accurately measured by the relationship between the arrival time difference of the lateral wave, the diffracted wave from the flaw, and the bottom echo along the flaw detection surface and the sound velocity. In the initial rough inspection, two probes are arranged around the weld line and scanned in parallel with the weld line (referred to as D-scan). Then, only for the flaw detection location, two probes are arranged around the flaw detection location, and are scanned at right angles to the weld line (referred to as B-scan).
[0010]
[Problems to be solved by the invention]
Recently, the following requirements have been raised.
[0011]
1. In the stage after the post-weld heat treatment (PWHT) of the pressure vessel, there is a great demand for performing a radiological inspection (RT) of the weld joint or an alternative automatic ultrasonic inspection (AUT). In such a case, in a pressure vessel made of clad steel and a pressure vessel of an internal build-up welding specification such as stainless steel / Inconel, a pass / fail judgment inspection must be performed including the build-up weld portion of the weld joint.
[0012]
2. Even in a pressure vessel made of clad steel (base material), clad steel pressure vessel whose thickness is determined by including a build-up weld in the strength member, and a pressure vessel with internal build-up welding specifications such as stainless steel / Inconel, Pass / fail judgment inspection must be performed including the weld overlay.
[0013]
However, it is very difficult to detect a flaw inherent in the build-up weld by the TOFD method, and pass / fail judgment is impossible. At present, the flaw detection / pass / fail judgment by the TOFD method is performed only in the base metal welded portion.
[0014]
In view of the above problems, and an object thereof is to provide the possibility ultrasonic flaw detector you simultaneous testing of base metal weld and overlay clad.
[0015]
Another object of the present invention is an ultrasonic flaw detection apparatus for a welded joint portion of a pressure vessel made of clad steel and a pressure vessel of an inner surface overlay welding specification such as stainless steel / Inconel. by performing the flaw detection by overlay clad simultaneous testing is to provide an ultrasonic flaw detector you permit alternative to acceptance judgment inspection radiation inspection (RT) method.
[0016]
The present invention also provides an ultrasonic flaw detection method suitable for the above-described system.
[0017]
[Means for Solving the Problems]
According to the present invention, there is provided an ultrasonic flaw detection method for performing ultrasonic flaw detection by a PA method and ultrasonic flaw detection by a TOFD method on a welded joint portion using a single ultrasonic flaw detection scanner. An ultrasonic flaw detection method characterized in that at the time of excitation of any ultrasonic transducer group in electronic scanning by the method, a probe used in the TOFD method is excited to perform the two types of ultrasonic flaw detection simultaneously. Provided.
[0018]
According to this ultrasonic flaw detection method, the single ultrasonic flaw detection scanner uses an array probe in which a large number of strip-shaped ultrasonic transducers are linearly arranged so as to extend in the width direction of the weld joint. In addition to performing an ultrasonic flaw detection by the PA method, an ultrasonic flaw detection by the TOFD method is performed using a transmission probe and a reception probe that are adjacent to the array probe and straddle the weld joint. It is characterized by that.
[0019]
According to the present invention, a first feeler means for performing ultrasonic flaw detection by PA method with respect to the weld joint portion, the welded joint portion and the second for performing ultrasonic flaw detection by TOFD method against Probe means, a single ultrasonic flaw scanner equipped with the first probe means and the second probe means, and operations of the first probe means and the second probe means An ultrasonic flaw detector comprising: a probe for use in a TOFD method at the time of excitation of any ultrasonic transducer group in an electronic scan by a PA method; There is provided an ultrasonic flaw detector characterized by controlling the operation timing so as to excite the vibration .
[0020]
In the ultrasonic flaw detection apparatus, the first probe means has an array probe in which a large number of strip-shaped ultrasonic transmission / reception transducers are linearly arranged so as to extend in the width direction of the weld joint, The second probe means includes a transmission probe and a reception probe provided adjacent to the array probe and straddling the weld joint .
[0021]
Further in this ultrasonic flaw detector, before Symbol second feeler means, wherein the ultrasonic transmitting oscillator in two different pairs of span between the receiving transducer and the transmitting transducer and ultrasonic receiving transducer It is characterized by having .
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. The present invention is characterized in that the PHASED ARRAY method (hereinafter referred to as PA method) is used in combination with the TOFD method for the purpose of defect detection / pass / fail judgment of the weld overlay. That is, the present invention provides an automatic ultrasonic flaw detector that performs simultaneous flaw detection of “base metal welded portion: TOFD method” + “build-up welded portion and base material welded portion: PA method”.
[0023]
The PA method itself is well known as disclosed in, for example, Japanese Patent Laid-Open No. 57-6377, and is also called an electronic scanning ultrasonic system. In simple terms, the PA method uses an array probe in which a large number of strip-shaped transducers for ultrasonic transmission / reception are linearly arranged, and by sequentially switching the transducer group to be excited simultaneously, the electronic scan is used to scan the data. It is a system that can record. Moreover, mechanical Y scanning at the time of carrying out the hand flaw detection (pulse echo method) is not required, and scanning (D-scan) is performed in parallel with the weld line. Further, in the PA method, the focal point can be freely converted by giving a desired delay time to the pulse to each transducer. In this embodiment, the focus of the ultrasonic beam by the PA method is adjusted to the build-up weld.
[0024]
Like the TOFD method, the PA method does not require a mechanical Y-scan of the probe (scanning in the direction perpendicular to the weld line), so the inspection time required to obtain the data for the TOFD / PA method combined system is TOFD. It is the same as a legal-only system and is extremely fast.
[0025]
The scratch detection capability of the PA method has already been verified by using a test piece in which various linear and spherical scratches are inherent in the build-up weld.
[0026]
In addition to pressure vessels made of solid materials such as carbon steel / Cr-Mo steel, we have developed a pressure vessel made of clad steel, and a pressure vessel made of stainless steel / Inconel, such as an internal overlay welding specification. An outline of the introduced automatic ultrasonic flaw detector: “Focus 32/64” (64-channel specification) will be described.
[0027]
Even in a pressure vessel having a base metal plate thickness of about 1.50 to 100 mm, the TOFD data can be obtained by simultaneous flaw detection. Therefore, among 64 channels, the 63rd and 64th channels are for TOFD (TOFD-1 / Used as TOFD-2).
[0028]
2. The first channel to the 62nd channel are used for the PA method. The maximum number of channels that can be excited simultaneously is 30 ({(64/2) -2}), and within that range, an appropriate simultaneous excitation transducer is selected to create a focal law (a group with a certain focal point and angle). Electronic scanning is performed between 62 channels (64-2).
[0029]
3. The TOFD method is effective for sizing the flaw depth / flaw length in the scanning direction, and the PA method can specify the flaw position / size with considerable accuracy. Although it is difficult to determine the nature of the flaw only with the TOFD method, as a feature of the combination of both types, a highly accurate flaw detection including the nature of the flaw becomes possible.
[0030]
4). Regarding computer image display, in addition to the TOFD image (D-scan), images such as C-scan (same view as RT film) and B-scan in the PA method can be displayed on the same screen.
[0031]
5). A TOFD-1 / TOFD-2 transmission probe, reception probe (4 in total) and one PA method probe (5 MHz, 64 elements) are attached to the same scanner. This scanner is used to move the TOFD-1 / TOFD-2 transmission probe, the reception probe, and the PA method probe in a direction along the weld line and a direction perpendicular thereto. .
[0032]
6). The flaw detection of the joint of the pressure vessel is performed by fixing the scanner with the five probes to the flaw detection surface with a stand and utilizing the rotation of the pressure vessel main body by the turning roller.
[0033]
With reference to FIGS. 1-3, the outline | summary of the automatic ultrasonic flaw detector by this invention is demonstrated. The automatic ultrasonic flaw detector includes a first probe 20 for performing ultrasonic flaw detection by the PA method on the build-up weld 11 and the base metal weld 12 in the weld joint 10, and a mother in the weld joint. Reception from the first probe unit 20 by controlling the operation timing of the second probe unit 30 for performing ultrasonic flaw detection on the material welding unit 12 by the TOFD method and the first probe unit 20 The signal is processed to detect the presence or absence of flaws in the build-up weld 11 and the base metal weld 12, and the operation timing of the second probe 30 is controlled to receive a signal received from the second probe 30. A control device (not shown) for processing and detecting the presence or absence of scratches in the base metal welded portion 12.
[0034]
The first probe 20 has an array probe 21 in which 64 strip ultrasonic transducers are linearly arranged so as to extend in the width direction of the weld joint 10. On the other hand, the second probe unit 30 is adjacent to the array probe 21 and is provided with two pairs of transmission probes 31T and 32T and reception probes 31R and 32R (TOFD-1) provided so as to straddle the weld beads. And TOFD-2). The two pairs of transmission probes 31T and 32T and the reception probes 31R and 32R are arranged before or after the array probe 21 with respect to the extending direction (D scan direction) of the welding joint portion 10. In particular, the first probe unit 20 and the second probe unit 30 are mounted on a scanner 40 that is movable in the extending direction of the weld joint 10 and in a direction perpendicular thereto. In FIG. 2, the arrows with arrows at both ends indicate that the two pairs of transmission probes 31T and 32T and the reception probes 31R and 32R can adjust the span between them according to the thickness of the base material. It means that there is.
[0035]
In this automatic ultrasonic flaw detector, the array probe 21 has first to 64th ultrasonic transducers for transmitting and receiving ultrasonic waves (hereinafter referred to as elements), of which the first to 62nd 62 are included. Each element is used for ultrasonic testing by the PA method.
[0036]
The control device has a function of controlling the operation timing for the first to 64th 64 elements. In particular, in this embodiment, the control device can be simultaneously excited element group consisting of 30, yet by switching sequentially the element group of simultaneously excited, so as to be able to speak performed electronically scanned Yes. That is, the control device first excites the first to thirty element groups at the same time to focus and irradiate ultrasonic waves from the thirty elements to a certain point on the build-up weld 11. The irradiation focused on one point can be realized by shifting the irradiation of the ultrasonic beam from each element using the excitation pulse delay circuit 22, and such a function is called an electron lens.
[0037]
FIG. 4 schematically shows the function of the electron lens. By controlling the excitation pulse delay circuit 22, a plurality of types of apparent electron lenses shown on the left in FIG. 4 can be realized. The position in the depth direction of the focusing point changes according to the apparent focal length of the electron lens.
[0038]
As a result of the irradiation as described above, the first to thirty elements receive the reflected ultrasonic waves irradiated from the respective elements and transmit them to the control device. Next, the control device simultaneously excites the 30 elements from the 2nd to the 31st to focus and radiate the ultrasonic waves from the 30 element group to one point shifted in the width direction of the build-up weld 11. . By performing this 33 times, scanning in the width direction of the welded joint portion 10 can be performed.
[0039]
The control device also operates the two pairs of transmission probes 31T and 32T and the reception probes 31R and 32R using the function of controlling the operation timing for the two elements of the 63rd and 64th elements, and The base material welded portion 12 is irradiated with ultrasonic waves every 33 times.
[0040]
The control device further focuses the ultrasonic waves from the 30 elements from the first to the thirty to a certain point of the build-up weld, and uses the received signal thereof to build the weld 11 and the base metal weld 12. Next, a process shifted in the width direction of the build-up welded part 11 and the base metal welded part 12 is performed using received signals from the 30th element from the 2nd to the 31st, and this is performed 33 times. By performing, the presence or absence of the damage | wound in the width direction of the build-up welding part 11 and the base material welding part 12 is detected.
[0041]
The control device also processes the received signals from the two receiving probes 31R and 32R by using the processing function for the received signals from the 63th and 64th two elements, thereby allowing the base metal welded part 12 to Detect scratches.
[0042]
In summary, the “Focus 32/64” 64 means the number of flaw detection information amounts (number of channels) that can be controlled independently. On the other hand, 32 means the number of channels that can be excited simultaneously (can transmit ultrasonic beams simultaneously). Note that flaw detection using only the TOFD method can be handled with one channel.
[0043]
TOFD-1 and TOFD-2 are employed in the automatic ultrasonic flaw detector in order to obtain TOFD data with different flaw detection conditions in simultaneous flaw detection. That is, the TOFD method is a flaw detection method using two transmission probes 31T and 32T and two reception probes 31R and 32R.
[0044]
Two pairs of transmission probes and reception probes are used for the following reason.
[0045]
For example, for a specimen having a thickness of 50 mm or more, in order to obtain flaw detection data of the entire plate thickness, it is necessary to perform flaw detection twice or more by changing the span between the transmission probe and the reception probe. .
[0046]
With this automatic ultrasonic flaw detector, independent flaw detection conditions differ for test specimens of 50 mm or more and 100 mm or less at the same time so that all flaw detection data can be obtained (by changing the span between the probes). E) TOFD-1 and TOFD-2. For this reason, two channels are required for TOFD-1 and TOFD-2. Therefore, the number of channels that can be used for the PA method is 64-2 = 62 channels, and as the PA method, it is 32-2 = 30 channels that can transmit an ultrasonic beam simultaneously with the TOFD method.
[0047]
On the other hand, the array probe 21 for the PA method is composed of 64 elements as shown in Table 1 below. That is, it can be considered that it is composed of 64 independent probes. The array probe 21 is physically one, and if the width of each element is 1 mm, the total width is about 64 mm.
[0048]
[Table 1]

[0049]
Of the 64 elements, 62 elements are used as the PA method, and the remaining 2 elements (numbers 63 and 64) are dummy. This is because the channels for elements 63 and 64 are used for TOFD-1 and TOFD-2.
[0050]
As shown in Table 1, among 64 elements of the probe for the PA method, 62 elements are assigned numbers 1 to 62 as channel numbers from the leftmost element in FIG.
[0051]
CONFIGURATION No. 1 to 33 and CONFIGURATION No. 34 and 35 (TOFD-1, TOFD-2) can be simultaneously excited. CONFIGURATION No. Switching from 1 to 33 is performed electronically (in units of 1 nanosecond) instantaneously.
[0052]
As described above, in the present embodiment, ultrasonic flaw detection is performed on the build-up weld 11 using the array probe 21 by the PA method, and two pairs of the transmission probes 31T and 32T and the reception probe are performed by the TOFD method. Ultrasonic flaw detection for the base metal welded portion 12 is performed simultaneously with the ultrasonic flaw detection for the build-up welded portion 11 using the sub-elements 31R and 32R.
[0053]
In the above embodiment, the case where the number of elements in the array probe 21 is 64 has been described, but it goes without saying that the number of elements is not limited to 64.
[0054]
Summarizing the above points, the effects of the above embodiment include the following points.
1. Detection and acceptance of welded joint parts of clad steel pressure vessels and pressure vessels with internal overlay welding specifications such as stainless steel / Inconel, etc. using an automatic ultrasonic deep wound device that uses the TOFD method and PA method (simultaneous deep wounds) Judgment inspection became possible not only for the base metal weld but also for the weld overlay.
[0055]
2. The combined use of the TOFD method and the PA method (simultaneous deep flaws) enables high-accuracy flaw detection including not only flaw detection / sizing but also flaw characterization.
[0056]
3. The inspection time required for obtaining the data of the combined system of TOFD method / PA method is the same as that of the system using only the TOFD method and is extremely fast. Compared with radiation inspection (RT), the inspection cost is greatly reduced.
[0057]
4). There is an increasing demand for radiation inspection (RT) at the stage after the post-weld heat treatment (PWHT) of the pressure vessel. In response to such a requirement, if the thickness is 4 inches or less, an on-code radiation inspection (RT) must be performed after PWHT. Conventionally, radiation inspection (RT) has been performed twice in total for quality confirmation before and after PWHT. On the other hand, before the PWHT, the soundness of the base metal welded portion / the build-up welded portion is confirmed by the automatic ultrasonic deep flaw device according to the above embodiment , and the radiation inspection (RT) is performed only after the PWHT. Is possible. This leads to a significant reduction in inspection costs.
[0058]
【The invention's effect】
As described above, according to the present invention, two different types of ultrasonic deep flaws, the TOFD method and the PA method, are simultaneously performed at the time of a single flaw detection using a single ultrasonic deep flaw scanner. High-accuracy ultrasonic testing with reduced inspection time is now possible.
[Brief description of the drawings]
FIG. 1 is a view for explaining ultrasonic flaw detection by a phased array method used in the present invention.
2 is a diagram showing a relationship between an ultrasonic flaw detection array probe used in the Phased Array method shown in FIG. 1 and a second probe used in the TOFD method as viewed from above. FIG.
3 is a diagram for explaining the operation of the array probe in FIG. 1; FIG.
4 is a diagram schematically showing a function of an electron lens realized by the array probe of FIG. 3. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Welding joint part 11 Overlay welding part 12 Base material welding part 20 1st probe part 21 Array probe 22 Excitation pulse delay circuit 30 2nd probe part 31T, 32T Transmission probe 31R, 32R Reception probe

Claims (5)

An ultrasonic flaw detection method for performing ultrasonic flaw detection by a PA method and ultrasonic flaw detection by a TOFD method on a weld joint using a single ultrasonic flaw detection scanner,
An ultrasonic flaw detection method characterized by exciting the probe used in the TOFD method at the time of excitation of any ultrasonic transducer group in electronic scanning by the PA method and simultaneously performing the two types of ultrasonic flaw detection. . The ultrasonic flaw detection method according to claim 1,
The single ultrasonic flaw detection scanner performs ultrasonic flaw detection by the PA method using an array probe in which a large number of strip-shaped ultrasonic transmission / reception transducers are linearly arranged so as to extend in the width direction of the weld joint. With
An ultrasonic flaw detection method comprising performing ultrasonic flaw detection by a TOFD method using a transmission probe and a reception probe provided adjacent to the array probe and straddling the weld joint . A first probe means for performing ultrasonic flaw detection by the PA method on the weld joint;
A second probe means for performing ultrasonic flaw detection by the TOFD method on the weld joint;
A single ultrasonic flaw scanner equipped with the first probe means and the second probe means;
A control device that controls the operation timing of the first probe means and the second probe means, and an ultrasonic flaw detector comprising :
The ultrasonic flaw detector is characterized in that the control device controls the operation timing so as to excite a probe used in the TOFD method when any of the ultrasonic transducer groups is excited in an electronic scan by the PA method . The ultrasonic flaw detector according to claim 3,
The first probe means has an array probe in which a large number of strip-shaped ultrasonic transmission / reception transducers are linearly arranged so as to extend in the width direction of the weld joint,
2. The ultrasonic flaw detector according to claim 1, wherein the second probe means includes a transmission probe and a reception probe provided adjacent to the array probe and straddling the weld joint . The ultrasonic flaw detector according to claim 4,
Before Stories second feeler means, ultrasonic waves and having a span of two different pairs of transducers and ultrasonic receiving transducer for ultrasonic wave transmission between the receiving transducers and the transmitting oscillator Flaw detection equipment.

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