JPH11142375A - Method for detecting minute defect of butt welded joint - Google Patents
Method for detecting minute defect of butt welded jointInfo
- Publication number
- JPH11142375A JPH11142375A JP9322005A JP32200597A JPH11142375A JP H11142375 A JPH11142375 A JP H11142375A JP 9322005 A JP9322005 A JP 9322005A JP 32200597 A JP32200597 A JP 32200597A JP H11142375 A JPH11142375 A JP H11142375A
- Authority
- JP
- Japan
- Prior art keywords
- power spectrum
- flaw detection
- welded joint
- frequency band
- defect
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/12—Analysing solids by measuring frequency or resonance of acoustic waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/04—Wave modes and trajectories
- G01N2291/044—Internal reflections (echoes), e.g. on walls or defects
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/26—Scanned objects
- G01N2291/269—Various geometry objects
- G01N2291/2695—Bottles, containers
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は主として、陸用ボイ
ラ耐圧部における小口管の突合せ溶接継手を超音波探傷
して内部に存在する微小欠陥を検出するための微小欠陥
検出方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a minute defect existing in a butt welding joint of a small mouth pipe in a land boiler pressure-resistant part by ultrasonically detecting a small defect inside the butt weld joint.
【０００２】[0002]
【従来の技術】超音波法による配管溶接部のような内部
の欠陥検出法として、超音波探傷波形のエコー高さ及び
伝搬時間などから欠陥の有無を判断する手法が従来より
知られている。2. Description of the Related Art As a method of detecting an internal defect such as a pipe weld by an ultrasonic method, a method of judging the presence or absence of a defect from the echo height and propagation time of an ultrasonic inspection waveform has been conventionally known.
【０００３】しかし、陸用ボイラ耐圧部小口管のうち、
炭素鋼及びオーステナイト系ステンレス鋼、炭素鋼とオ
ーステナイト系ステンレス鋼の異材で管肉厚が３．５mm
未満の突合せ溶接継手については、検査コストや作業性
の面で有利な超音波探傷試験を行うことができないの
で、現在では、放射線試験により検査が行われている。
これは、オーステナイト系ステンレス鋼や異材継手の場
合、溶接部の柱状晶の音響異方性によって欠陥検出が困
難となり、又、管肉厚３．５mm未満の薄肉管では、通常
の斜角探傷の適用が困難であるという理由からである。[0003] However, in the small-bore pipe of the pressure-resistant part of the land boiler,
Tube thickness of 3.5mm made of carbon steel and austenitic stainless steel, and different materials of carbon steel and austenitic stainless steel
Butt-welded joints with less than a butt-welded joint cannot be subjected to an ultrasonic flaw detection test that is advantageous in terms of inspection cost and workability.
This is because, in the case of austenitic stainless steel or dissimilar material joints, it is difficult to detect defects due to the acoustic anisotropy of the columnar crystals in the welded portion. This is because it is difficult to apply.
【０００４】因に、薄肉管の超音波探傷試験に適してい
るものとしては、クリーピング波探触子が知られてい
る。[0004] A creeping wave probe is known as one suitable for an ultrasonic inspection test of a thin-walled tube.
【０００５】[0005]
【発明が解決しようとする課題】ところが、クリーピン
グ波探触子を用いて超音波探傷を行った場合でも、図４
に示す如き探傷波形データのピークエコーの大きさで評
価することになるため、たとえば、φ０．８mmとかφ
１．０mmの如き微小なブローホールは、ＳＮ比が悪くて
検出が困難である。特に、オーステナイト系ステンレス
鋼の溶接部はノイズエコーが非常に多いため、探傷波形
上のピークエコーで評価しようとしてもＳＮ比が悪過ぎ
て検出できないのが実情である。However, even when ultrasonic testing is performed using a creeping wave probe, FIG.
In order to evaluate with the magnitude of the peak echo of the flaw detection waveform data as shown in FIG.
A fine blowhole as small as 1.0 mm has a poor SN ratio and is difficult to detect. In particular, the welded part of austenitic stainless steel has a very large number of noise echoes, and in fact, even when trying to evaluate with a peak echo on a flaw detection waveform, the SN ratio is too bad to detect.
【０００６】そこで、本発明は、炭素鋼及びオーステナ
イト系ステンレス鋼、炭素鋼とオーステナイト系ステン
レス鋼の異材で管肉厚が３．５mm未満の突合せ溶接継手
に適用できて、ＳＮ比が悪くノイズエコーが多くても微
小ブローホールの如き微小欠陥を精度よく検出すること
ができるような突合せ溶接継手の微小欠陥検出方法を提
供しようとするものである。Therefore, the present invention can be applied to butt-welded joints made of carbon steel and austenitic stainless steel, and different materials of carbon steel and austenitic stainless steel and having a pipe wall thickness of less than 3.5 mm. It is an object of the present invention to provide a method for detecting a small defect of a butt-welded joint which can accurately detect a small defect such as a small blowhole even if the number of the small defects is large.
【０００７】[0007]
【課題を解決するための手段】本発明は、上記課題を解
決するために、突合せ溶接継手の超音波探傷波形データ
をとり、次に、該超音波探傷波形データのゲート部分を
ＦＦＴ演算してパワースペクトルを求め、しかる後、該
パワースペクトルが無欠陥部から変化している特定周波
数帯域のみを解析して、解析値の大小により微小欠陥を
検出する突合せ溶接継手の微小欠陥検出方法とする。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention obtains ultrasonic flaw detection waveform data of a butt-welded joint, and then performs an FFT operation on a gate portion of the ultrasonic flaw detection waveform data. A power spectrum is obtained, and thereafter, only a specific frequency band in which the power spectrum is changed from the defect-free portion is analyzed, and a micro defect detection method for a butt welded joint for detecting a micro defect according to the magnitude of the analysis value is provided.
【０００８】超音波探傷波形データのゲート部分のパワ
ースペクトルを基に、特定周波数帯域の解析値から微小
欠陥が検出されるので、ＳＮ比が悪くノイズエコーが多
くて欠陥検出が困難であった異材継手等の欠陥検出を容
易に行うことができるようになる。[0008] Since a minute defect is detected from an analysis value in a specific frequency band based on the power spectrum of the gate portion of the ultrasonic flaw detection waveform data, a different material having a poor S / N ratio and many noise echoes making defect detection difficult. It becomes possible to easily detect defects such as joints.
【０００９】又、特定周波数帯域の解析として、該特定
周波数帯域の範囲を積分して面積を算出することによ
り、精度よく微小欠陥を検出することができるようにな
る。Further, as an analysis of a specific frequency band, a minute defect can be detected with high accuracy by integrating the range of the specific frequency band and calculating the area.
【００１０】[0010]
【発明の実施の形態】以下、本発明の実施の形態を図面
を参照して説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００１１】図１は本発明の突合せ溶接継手の微小欠陥
検出方法のフローチャートを示すもので、先ず、一対一
組とした送信用斜角探触子と受信用斜角探触子を組み付
けたスキャナーにより、検査対象となる小径管の突合せ
溶接継手を超音波探傷して、図４に示す如き超音波探傷
波形データをとる。次に、超音波探傷波形データ中のゲ
ート部分ＧをＦＦＴ（高速フーリエ変換）演算して、図
２に示す如きパワースペクトルを求める。しかる後、上
記パワースペクトルの所要の特定周波数帯域のみを解析
し、解析値の大小により微小欠陥を検出する。FIG. 1 is a flow chart of a method for detecting a micro defect in a butt-welded joint according to the present invention. First, a scanner in which a transmission bevel probe and a reception bevel probe are assembled in a one-to-one pair. Thereby, the butt-welded joint of the small-diameter pipe to be inspected is subjected to ultrasonic flaw detection, and ultrasonic flaw detection waveform data as shown in FIG. 4 is obtained. Next, the gate portion G in the ultrasonic flaw detection waveform data is subjected to FFT (Fast Fourier Transform) to obtain a power spectrum as shown in FIG. Thereafter, only the required specific frequency band of the power spectrum is analyzed, and a minute defect is detected based on the magnitude of the analysis value.
【００１２】上記において、解析すべき特定周波数帯域
は、本実施の形態では、Ｂ１〜Ｂ５のうちのＢ２として
ある。因に、各種供試体を用いた試験によると、ＳＮ比
が悪くノイズエコーが多くても、欠陥の情報が含まれて
いれば、無欠陥部との比較によりパワースペクトルが変
化することが確認されている。したがって、この特定周
波数帯域Ｂ２の範囲を積分して面積を算出すると、図３
に一例を示す如くなり、解析値の大きさで欠陥の有無を
判断することができる。すなわち、図３において、周波
数解析値が２５０以下の部分がノイズエコー（欠陥とは
ならないφ０．５mm以下の微小ブローホールを含む）に
相当し、ノイズエコーの部分よりも上方に浮き出た部分
が微小欠陥となるφ０．８mmとかφ１．０mmオーダーの
微小ブローホールＢＨとなる。この場合、１３５度付近
と３１５度付近の位置に微小ブローホールＢＨが存在し
ていることになる。In the above, the specific frequency band to be analyzed is B2 among B1 to B5 in the present embodiment. However, according to tests using various specimens, it was confirmed that even if the SN ratio was poor and there were many noise echoes, if the defect information was included, the power spectrum changed by comparison with the non-defective part. ing. Therefore, when the area is calculated by integrating the range of the specific frequency band B2, FIG.
An example is shown below, and the presence or absence of a defect can be determined based on the magnitude of the analysis value. That is, in FIG. 3, a portion having a frequency analysis value of 250 or less corresponds to a noise echo (including a minute blowhole having a diameter of 0.5 mm or less which is not a defect), and a portion protruding above the noise echo portion is a minute echo. A minute blow hole BH of the order of φ0.8 mm or φ1.0 mm serving as a defect is formed. In this case, the minute blow holes BH exist at positions around 135 degrees and around 315 degrees.
【００１３】このように、本発明では、欠陥情報が含ま
れていればパワースペクトルの或る特定周波数帯域が最
も変化することに着目し、この範囲を解析して解析値の
大きさで微小欠陥の有無を判断するようにしたので、炭
素鋼及びオーステナイト系ステンレス鋼、炭素鋼とオー
ステナイト系ステンレス鋼の異材で管肉厚が３．５mm未
満の突合せ溶接継手についても、微小欠陥を精度よく検
出することができる。As described above, in the present invention, attention is paid to the fact that a certain frequency band of the power spectrum changes most if defect information is included, and this range is analyzed. The presence or absence of a small defect is accurately detected even for butt-welded joints of carbon steel and austenitic stainless steel, and different materials of carbon steel and austenitic stainless steel with a pipe wall thickness of less than 3.5 mm. be able to.
【００１４】なお、本発明は上記実施の形態にのみ限定
されるものではなく、本発明の要旨を逸脱しない範囲内
において種々変更を加え得ることは勿論である。It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the scope of the present invention.
【００１５】[0015]
【発明の効果】以上述べた如く、本発明の突合せ溶接継
手の微小欠陥検出方法によれば、突合せ溶接継手の超音
波探傷波形データをとり、次に、該超音波探傷波形デー
タのゲート部分をＦＦＴ演算してパワースペクトルを求
め、しかる後、該パワースペクトルが無欠陥部から変化
している特定周波数帯域のみを解析して、解析値の大小
により微小欠陥を検出するようにさせるので、従来、Ｓ
Ｎ比が悪くノイズエコーが多くて超音波探傷検査を行う
ことができなかった炭素鋼及びオーステナイト系ステン
レス鋼、炭素鋼とオーステナイト系ステンレス鋼の異材
で管肉厚が３．５mm未満の突合せ溶接部についても、超
音波探傷波形データを基に微小欠陥を検出することがで
き、放射線試験による場合に比して、検査コストや作業
性の面で有利となり、又、特定周波数帯域の解析とし
て、その範囲を積分して面積を算出するようにすること
によって、微小欠陥をノイズと分けて精度よく検出する
ことができる、等の優れた効果を発揮する。As described above, according to the method for detecting micro defects of a butt welded joint according to the present invention, the ultrasonic flaw detection waveform data of the butt welded joint is obtained, and then the gate portion of the ultrasonic flaw detection waveform data is obtained. Since a power spectrum is obtained by performing an FFT operation, and only a specific frequency band in which the power spectrum is changed from a defect-free portion is analyzed, and a minute defect is detected based on the magnitude of the analysis value. S
Butt welds with a pipe wall thickness of less than 3.5 mm made of carbon steel and austenitic stainless steel, and carbon steel and austenitic stainless steel that were not able to be subjected to ultrasonic inspection because of poor N ratio and many noise echoes Can also detect minute defects based on ultrasonic flaw detection waveform data, which is advantageous in terms of inspection cost and workability as compared with the case of radiation testing, and also as an analysis of a specific frequency band. By calculating the area by integrating the range, it is possible to obtain an excellent effect such that a minute defect can be detected with high accuracy separately from noise.
【図１】本発明の突合せ溶接継手の微小欠陥検出方法を
示すフローチャートである。FIG. 1 is a flowchart showing a method for detecting a small defect in a butt-welded joint according to the present invention.
【図２】超音波探傷波形データのゲート部分をＦＦＴ演
算して得られたパワースペクトルの一例を示す図であ
る。FIG. 2 is a diagram illustrating an example of a power spectrum obtained by performing an FFT operation on a gate portion of ultrasonic inspection waveform data.
【図３】パワースペクトルの特定周波数帯域を解析した
結果の一例を示す図である。FIG. 3 is a diagram illustrating an example of a result of analyzing a specific frequency band of a power spectrum.
【図４】超音波探傷波形データの一例を示す図である。FIG. 4 is a diagram showing an example of ultrasonic flaw detection waveform data.
Ｇ ゲート部分 Ｂ１，Ｂ２，Ｂ３，Ｂ４，Ｂ５ 周波数帯域 ＢＨ 微小ブローホール（微小欠陥） G Gate part B1, B2, B3, B4, B5 Frequency band BH Micro blow hole (micro defect)
Claims (2)
をとり、次に、該超音波探傷波形データのゲート部分を
ＦＦＴ演算してパワースペクトルを求め、しかる後、該
パワースペクトルが無欠陥部から変化している特定周波
数帯域のみを解析して、解析値の大小により微小欠陥を
検出することを特徴とする突合せ溶接継手の微小欠陥検
出方法。1. An ultrasonic flaw detection waveform data of a butt-welded joint is obtained, and then a power spectrum is obtained by performing an FFT operation on a gate portion of the ultrasonic flaw detection waveform data. A method for detecting a small defect in a butt-welded joint, wherein only a changing specific frequency band is analyzed, and a small defect is detected based on a magnitude of the analysis value.
波数帯域の範囲を積分して面積を算出するようにした請
求項１記載の突合せ溶接継手の微小欠陥検出方法。2. The method according to claim 1, wherein, as the analysis of the specific frequency band, the area of the specific frequency band is integrated to calculate the area.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9322005A JPH11142375A (en) | 1997-11-10 | 1997-11-10 | Method for detecting minute defect of butt welded joint |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9322005A JPH11142375A (en) | 1997-11-10 | 1997-11-10 | Method for detecting minute defect of butt welded joint |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11142375A true JPH11142375A (en) | 1999-05-28 |
Family
ID=18138865
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9322005A Pending JPH11142375A (en) | 1997-11-10 | 1997-11-10 | Method for detecting minute defect of butt welded joint |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11142375A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007017300A (en) * | 2005-07-07 | 2007-01-25 | Toshiba Corp | Surface inspection device and surface inspection method |
| KR100830107B1 (en) | 2005-07-07 | 2008-05-20 | 가부시끼가이샤 도시바 | Laser-based maintenance apparatus |
| CN103018331A (en) * | 2011-09-22 | 2013-04-03 | 北京理工大学 | Frequency domain imaging method of ultrasonic scanning microscope |
-
1997
- 1997-11-10 JP JP9322005A patent/JPH11142375A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007017300A (en) * | 2005-07-07 | 2007-01-25 | Toshiba Corp | Surface inspection device and surface inspection method |
| KR100830107B1 (en) | 2005-07-07 | 2008-05-20 | 가부시끼가이샤 도시바 | Laser-based maintenance apparatus |
| JP4746365B2 (en) * | 2005-07-07 | 2011-08-10 | 株式会社東芝 | Surface inspection method |
| US8094297B2 (en) | 2005-07-07 | 2012-01-10 | Kabushiki Kaisha Toshiba | Laser-based maintenance apparatus for inspecting flaws |
| US8248595B2 (en) | 2005-07-07 | 2012-08-21 | Kabushiki Kaisha Toshiba | Laser-based maintenance apparatus for inspecting flaws based on a generated surface wave |
| CN103018331A (en) * | 2011-09-22 | 2013-04-03 | 北京理工大学 | Frequency domain imaging method of ultrasonic scanning microscope |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108562647B (en) | PA-TOFD combined ultrasonic detection device and method for polyethylene pipeline hot-melt butt joint | |
| JP4910770B2 (en) | Tubular ultrasonic inspection apparatus and ultrasonic inspection method | |
| JP4910769B2 (en) | Pipe quality control method and manufacturing method | |
| US9074927B2 (en) | Methods for non-destructively evaluating a joined component | |
| JP2008209356A (en) | Method of calibrating ultrasonic flaw detection, and quality control method and manufacturing method of tube | |
| JP2007163470A (en) | Apparatus and method for ultrasonically detecting flaw of tube | |
| CN101694484A (en) | Method for ultrasonic locating defect in austenitic stainless steel weld joint | |
| JPS61111461A (en) | Ultrasonic flaw detecting method of welded part of seam welded pipe | |
| CA2258913C (en) | Ultrasonic technique for inspection of weld and heat-affected zone for localized high temperature hydrogen attack | |
| JP2007322350A (en) | Ultrasonic flaw detector and method | |
| JPH11142375A (en) | Method for detecting minute defect of butt welded joint | |
| JP4364031B2 (en) | Ultrasonic flaw detection image processing apparatus and processing method thereof | |
| JP4120360B2 (en) | Ultrasonic spot weld evaluation method and apparatus | |
| JP2007178186A (en) | Ultrasonic flaw detection method and ultrasonic flaw detection apparatus | |
| CN205691552U (en) | A kind of heat exchanger tube sheet angle welding ultrasound wave automatic detection device | |
| CN112326798B (en) | Ultrasonic detection method for crane T-shaped weld joint region defects | |
| JP2002214204A (en) | Ultrasonic flaw detector and method using the same | |
| CN114019024A (en) | Method and system for measuring penetration depth of lower layer of weld joint in lap welding | |
| JP2005083907A (en) | Defect inspection method | |
| JPH01223342A (en) | Manufacture of reference test object for non-destructive inspection | |
| Long et al. | Further development of a conformable phased array device for inspection over irregular surfaces | |
| JP2008111742A (en) | Method and apparatus for non-destructive inspection of wheel welded part | |
| JP3754669B2 (en) | Ultrasonic flaw detection apparatus and ultrasonic flaw detection method | |
| JP2007132770A (en) | Plate member inspection method and device | |
| JP2009097876A (en) | Ultrasonic flaw detection method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20040628 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20050824 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20050913 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20060124 |