JP2002062281A - Flaw depth measuring method and its device - Google Patents

Flaw depth measuring method and its device

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Publication number
JP2002062281A
JP2002062281A JP2000246386A JP2000246386A JP2002062281A JP 2002062281 A JP2002062281 A JP 2002062281A JP 2000246386 A JP2000246386 A JP 2000246386A JP 2000246386 A JP2000246386 A JP 2000246386A JP 2002062281 A JP2002062281 A JP 2002062281A
Authority
JP
Japan
Prior art keywords
defect
ultrasonic
defect depth
depth
surface layer
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
Application number
JP2000246386A
Other languages
Japanese (ja)
Inventor
Koji Murakami
功治 村上
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
Original Assignee
Toshiba Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Toshiba Corp filed Critical Toshiba Corp
Priority to JP2000246386A priority Critical patent/JP2002062281A/en
Publication of JP2002062281A publication Critical patent/JP2002062281A/en
Pending legal-status Critical Current

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  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

PROBLEM TO BE SOLVED: To accurately measure a flaw depth in an initial stage so as to evaluate safety, flaw development based on initial flaw detection, and a remaining lifetime of a pressure vessel, a structural body, and the like in an operation plant. SOLUTION: Scanning by an ultrasonic probe 20, in which a plurality of ultrasonic flaw detecting vibrators 21a, 21b are adjacently arranged while separated from each other by means of an acoustic separation material 23, is carried out in a surface layer part of the structural body as a specimen or carried out above the structural body having a thin cross section. Ultrasonic beams are focused on the vicinity of the surface layer part of the specimen from the vibrators for generating vibration, and diffracted waves or scattered waves from the tip part of a minute shallow flaw part are received. On the basis of a measured ultrasonic propagation time and a distance between ultrasonic incident points in emission and receipt of the vibration, the flaw depth in the structural body surface layer part or the structural body as the specimen having a thin cross section is measured.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は非破壊検査等により
発見された構造物の割れ等の欠陥に対し、余寿命評価を
行う上で必要となる欠陥の大きさ(深さ情報)を測定す
るための欠陥深さ測定方法に係り、特に従来困難であっ
た構造物表層部または薄い断面を有する構造物の欠陥深
さの測定を可能とした欠陥深さ測定方法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures the size (depth information) of a defect necessary for evaluating the remaining life of a defect such as a crack of a structure found by a nondestructive inspection or the like. And a defect depth measuring method for measuring the defect depth of a structure having a surface layer portion or a thin cross section, which has been conventionally difficult.

【0002】[0002]

【従来の技術】構造物の非破壊検査においては、強度上
許容されるサイズのモデル欠陥と比較して欠陥の検出感
度を決定し、合否を判定するのが一般的である。しか
し、発電プラント等における損傷時の影響の大きい構造
物においては、破壊力学的手法からその余寿命を決定す
るために、欠陥発生初期の段階(微小欠陥)から、その
大きさ(深さ情報)を把握することが望ましい。
2. Description of the Related Art In a nondestructive inspection of a structure, it is general to determine a defect detection sensitivity by comparing the defect detection sensitivity with a model defect having an allowable size in terms of strength, and to judge pass / fail. However, in the case of a structure that is greatly affected by damage at a power plant or the like, its size (depth information) starts from the initial stage of defect generation (micro defects) in order to determine its remaining life from fracture mechanics. It is desirable to grasp.

【0003】このような発電プラントにおける初期欠陥
は一般に、供用中検査(ISI)において目視検査や超
音波探傷等の非破壊検査により検出されるが、欠陥深さ
測定においては、構造物の配置や形状の関係から超音波
探触子の望ましいアクセスが制限され、計画した探傷を
行えないことがある。
[0003] Initial defects in such a power plant are generally detected by a non-destructive inspection such as a visual inspection or an ultrasonic flaw detection in an in-service inspection (ISI). Desirable access of the ultrasonic probe is restricted due to the shape, and the planned flaw detection may not be performed.

【0004】以下に、超音波探傷を利用した欠陥深さ測
定の従来技術について述べる。
A conventional technique for measuring the depth of a defect using ultrasonic flaw detection will be described below.

【0005】図13は、従来技術による欠陥深さ検出
(端部エコー法)の一例として、厚肉構造物の裏面(探
傷面と反対側の面)にある欠陥の検出を行なう場合を例
示した説明図である。また、図14は同じく端部エコー
法により構造物表面(探傷面)の欠陥の検出を行なう場
合を例示した説明図である。
FIG. 13 shows an example of a conventional technique for detecting a defect depth (edge echo method) in which a defect is detected on the back surface (the surface opposite to the flaw detection surface) of a thick structure. FIG. FIG. 14 is an explanatory view exemplifying a case where a defect on the surface of a structure (flaw detection surface) is similarly detected by the edge echo method.

【0006】これらの図13および図14に示すよう
に、端部エコー法においては、構造物1の探傷面側およ
び探傷面と反対側から内部に向って発生した欠陥2a,
2bの深さHを精度良く測定できる手法として良く知ら
れている。本手法では、割れ等の面状の欠陥2a,2b
に対して斜めに超音波を入射させると、図13および図
14にグラフ表示したように、欠陥の端部からエコー1
0,11,12が得られる。これらエコーのピークが得
られた時のビーム路程Wと、使用した探触子3の屈折角
θとに基づいて、欠陥寸法Hを得るものである。
As shown in FIGS. 13 and 14, in the edge echo method, defects 2a, 2a, 2a,
It is well known as a method capable of measuring the depth H of 2b with high accuracy. In this method, planar defects 2a and 2b such as cracks
When an ultrasonic wave is made obliquely incident on the defect, as shown in the graphs of FIGS.
0, 11, and 12 are obtained. The defect dimension H is obtained based on the beam path W when these echo peaks are obtained and the refraction angle θ of the probe 3 used.

【0007】しかし一般に、このような端部エコーは欠
陥先端部での散乱波のため微弱であり、オーステナイト
系等の超音波散乱減衰が著しい材料においては、ノイズ
の発生等から端部エコーを見分けるのが困難な場合があ
る。さらに図14に示したように、欠陥が探傷面側の浅
い欠陥(表面から5mm以内程度)である場合について
は、その領域が探傷不能領域となり、欠陥端部からの信
号を検出することが困難であった。
However, such edge echoes are generally weak due to scattered waves at the tip of the defect, and in materials such as austenitic materials which have a significant attenuation of ultrasonic scattering, the edge echoes can be distinguished from noise generation. Can be difficult. Further, as shown in FIG. 14, when the defect is a shallow defect on the inspection surface side (within about 5 mm from the surface), the area becomes an undetectable area, and it is difficult to detect a signal from the edge of the defect. Met.

【0008】次に、図15〜図18によって、別の従来
技術による欠陥深さ検出として、英国のSilkによっ
て開発された欠陥深さの測定精度が高いTOFD法(T
ime−Of−Flight Diffraction
Technique)による場合(裏面検出)を説明
する。
Next, referring to FIGS. 15 to 18, as another conventional defect depth detection, TOFD method (T
im-Of-Flight Diffraction
(Technique) (backside detection) will be described.

【0009】図15は裏面側の欠陥検出例を示してお
り、図16〜図18は表面側の欠陥検出例を示している
(図18の場合は、薄肉材)。
FIG. 15 shows an example of defect detection on the back side, and FIGS. 16 to 18 show examples of defect detection on the front side (in the case of FIG. 18, a thin material).

【0010】この手法では、図15〜図18に示すよう
に、斜角探傷用の超音波探触子3a,3bを互いに向か
い合わせに配置し、一方を送信用、他方を受信用として
設定する。送信用探触子3aおよび受信用探触子3bを
入射点間距離一定として欠陥を横断して走査させると、
超音波の拡散により、材料表面を直接伝搬してくる表面
波(Lateral Wave)4、欠陥先端部を経由
して伝搬してくる回折波または散乱波5(Diffra
cted Wave)、および裏面で反射して伝搬して
くる底面反射波(Back−wall Echo)6が
受信される。このうち、欠陥2a,2bの先端部からの
回折波または散乱波5を検出し、その伝搬時間と入射点
間距離とに基づいて幾何学的に欠陥2a,2bの深さを
測定する。
In this method, as shown in FIGS. 15 to 18, the ultrasonic probes 3a and 3b for oblique flaw detection are arranged to face each other, and one is set for transmission and the other is set for reception. . When the transmission probe 3a and the reception probe 3b are scanned across the defect with the distance between incident points constant,
Due to the diffusion of the ultrasonic wave, a surface wave (Lateral Wave) 4 directly propagating on the surface of the material, a diffracted or scattered wave 5 (Diffra) propagating through the tip of the defect.
cted Wave) and a bottom-surface reflected wave (Back-wall Echo) 6 that is reflected and propagated on the back surface. Among them, the diffracted or scattered waves 5 from the tips of the defects 2a and 2b are detected, and the depths of the defects 2a and 2b are geometrically measured based on the propagation time and the distance between the incident points.

【0011】しかし、この手法においても、探触子3
a,3bの大きさによって決まる探触子同士の接近距離
の限界によって、図16および図17に示した表層部近
傍の欠陥2bについては探傷が不能となり、欠陥側から
の探傷においては欠陥深さが評価できない。また、図1
8に示した板厚が薄い構造物1においては、市販の探触
子によってはビームの太さにより音場が複雑になり、探
傷不能となることがある。
However, even in this method, the probe 3
Due to the limit of the approach distance between the probes determined by the sizes of a and 3b, flaw detection becomes impossible for the defect 2b near the surface layer shown in FIGS. 16 and 17, and the flaw depth in the flaw detection from the defect side. Cannot be evaluated. FIG.
In the structure 1 having a small plate thickness as shown in FIG. 8, the sound field becomes complicated due to the thickness of the beam depending on a commercially available probe, so that flaw detection may not be possible.

【0012】以上の2例に対し、さらに他の方法も知ら
れている。すなわち、欠陥側から探傷し、その深さを測
定できる表面波法である。図19(a),(b)は、こ
の表面波法による欠陥深さ検出の一例(厚肉材検出例)
を示す説明図であり、図20(a),(b)は表面波法
を薄肉材に適用した場合を示す説明図である。表面波と
は、表層部(表面から1波長程度の深さ)に集中し、表
面に沿って伝搬する超音波である。
Still other methods are known for the above two examples. That is, it is a surface wave method that can detect a flaw from the defect side and measure its depth. FIGS. 19A and 19B show an example of a defect depth detection by the surface wave method (example of detecting a thick material).
20 (a) and (b) are explanatory diagrams showing a case where the surface wave method is applied to a thin material. The surface wave is an ultrasonic wave that is concentrated on a surface layer (a depth of about one wavelength from the surface) and propagates along the surface.

【0013】図19の例は、一探触子法である。この方
法においては、同図(a)に示すように、超音波探触子
3からの表面波が構造物1の表面開口欠陥2の開口部
A,Cおよび欠陥の先端部Bで反射するので、同図
(b)に示すように、これらエコーのビーム路程差から
欠陥深さHを求める。
The example shown in FIG. 19 is a one probe method. In this method, as shown in FIG. 1A, the surface waves from the ultrasonic probe 3 are reflected at the openings A and C of the surface opening defect 2 of the structure 1 and the tip B of the defect. As shown in FIG. 3B, the defect depth H is obtained from the difference in beam path between these echoes.

【0014】また、図20の例は、二探触子法である。
この方法においては、同図(a)に示すように、探触子
3a,3b間の距離を一定値に固定して、健全部の受信
信号Dのビーム路程を読み取り、次に欠陥をまたいで探
触子3bを配置した時に欠陥先端を経由してくる受信信
号Eのビーム路程を読み取る。そして、同図(b)に示
すように、これらのビーム路程の差から欠陥深さを測定
するものである。
The example in FIG. 20 is a two-probe method.
In this method, as shown in FIG. 2A, the distance between the probes 3a and 3b is fixed to a constant value, the beam path of the received signal D of the sound portion is read, and then the defect is straddled. The beam path of the reception signal E passing through the tip of the defect when the probe 3b is arranged is read. Then, as shown in FIG. 3B, the depth of the defect is measured from the difference between these beam paths.

【0015】しかし、これらのいずれの方法において
も、欠陥内部に液体が入っていたり、欠陥が閉じている
場合、さらには表面の付着物により測定精度が悪くなる
か、もしくは、測定不能となる。
However, in any of these methods, when a liquid is contained in the defect or when the defect is closed, the measurement accuracy is deteriorated due to the adhered substance on the surface, or the measurement becomes impossible.

【0016】[0016]

【発明が解決しようとする課題】以上のように、従来技
術によっては、液体で満たされた環境下でかつ欠陥側に
しか探触子がアクセスできない場合において、欠陥深さ
を測定できる有効な方法がなく、発生した欠陥を初期の
段階から評価することができないものであった。
As described above, depending on the prior art, an effective method for measuring the depth of a defect in an environment filled with liquid and when the probe can access only the defect side. Thus, the generated defects could not be evaluated from an early stage.

【0017】なお、ここで断っておかなければならない
ことは、現在産業界において使用されている二振動子形
垂直探触子との相違点である。すなわち、二振動子形探
触子は表層部欠陥の検出を目的として考案された探触子
である。しかし、二振動子形探触子における振動子分割
の目的は、ある深さの表層部に超音波の交軸がくるよう
に設計され、不感帯を減少させるためであり、欠陥深さ
の測定は不可能である。
What must be noted here is the difference from the dual element vertical probe currently used in the industrial world. That is, the dual element probe is a probe designed for the purpose of detecting a surface layer defect. However, the purpose of the transducer division in the dual transducer type probe is to reduce the dead zone because the cross axis of the ultrasonic wave is designed to come to the surface layer at a certain depth. Impossible.

【0018】本発明はこのような事情に鑑みてなされた
ものであり、上述した従来の超音波探傷技術(端部エコ
ー法、TOFD法、表面波法)において評価することが
困難であった表層部、または薄肉材における欠陥の検出
および深さ測定を確実に行うことができ、このように発
生した欠陥をできるだけ初期の段階でその寸法(深さ)
を測定することにより、余寿命評価に有効に貢献できる
欠陥深さ測定方法を提供することを目的とする。
The present invention has been made in view of such circumstances, and the surface layer which has been difficult to evaluate in the above-described conventional ultrasonic flaw detection techniques (edge echo method, TOFD method, surface wave method). Defect detection and depth measurement in a part or thin-walled material can be performed reliably, and the defect generated in this way can be measured in its dimensions (depth) as early as possible.
It is an object of the present invention to provide a method for measuring the depth of a defect, which can effectively contribute to the evaluation of the remaining life by measuring the defect depth.

【0019】[0019]

【課題を解決するための手段】前記の目的を達成するた
めに、請求項1の発明では、複数の超音波探傷用振動子
を音響隔離材によって隔離した状態で隣接配置した超音
波探触子を、被検査体としての構造物表層部または薄い
断面を有する構造物上で走査させるとともに、前記振動
子から前記被検査体の表層部周辺に超音波ビームを集中
させて発振し、微小な浅い欠陥先端部からの回折波また
は散乱波を受信して、計測される超音波の伝搬時間と、
発振および受信における超音波入射点間の距離とに基づ
き、前記構造物表層部または薄い断面を有する前記被検
査体である構造物の欠陥深さを測定することを特徴とす
る欠陥深さ測定方法を提供する。
According to the first aspect of the present invention, there is provided an ultrasonic probe in which a plurality of ultrasonic flaw detecting transducers are arranged adjacent to each other while being separated by an acoustic isolating material. Is scanned on the surface of the structure as a test object or on a structure having a thin cross section, and the ultrasonic beam is oscillated by concentrating an ultrasonic beam around the surface layer of the test object from the vibrator to generate a small shallow Receiving a diffracted or scattered wave from the defect tip, and the propagation time of the measured ultrasonic wave,
A defect depth measuring method, comprising: measuring a defect depth of a structure which is the inspection object having a surface layer portion or a thin section of the structure based on a distance between ultrasonic incidence points in oscillation and reception. I will provide a.

【0020】請求項2の発明では、請求項1記載の欠陥
深さ測定方法において、超音波探触子の音響隔離材によ
って隔離された一方の振動子を発振側、他方を受信側と
して使用することを特徴とする欠陥深さ測定方法を提供
する。
According to a second aspect of the present invention, in the defect depth measuring method according to the first aspect, one vibrator isolated by the acoustic isolator of the ultrasonic probe is used as an oscillation side, and the other is used as a reception side. A method of measuring a depth of a defect is provided.

【0021】請求項3の発明では、請求項1または2記
載の欠陥深さ測定方法において、超音波入射点間距離を
被検査体の板厚変化に応じて補正し、その補正値を欠陥
深さ測定の計算式に反映させることを特徴とする欠陥深
さ測定方法を提供する。
According to a third aspect of the present invention, in the defect depth measuring method according to the first or second aspect, the distance between the ultrasonic wave incident points is corrected in accordance with a change in the thickness of the inspection object, and the correction value is determined. The present invention provides a method for measuring the depth of a defect, which is reflected in a calculation formula for measuring the depth.

【0022】請求項4の発明では、請求項2又は3記載
の欠陥深さ測定方法において、振動子としてそれぞれ複
数の振動子要素を集合させたものを使用するとともに、
それぞれその要素に遅延回路を接続し、前記各要素の電
子的走査により屈折角を微調整して欠陥深さ測定を行な
うことを特徴とする欠陥深さ測定方法を提供する。
According to a fourth aspect of the present invention, in the defect depth measuring method of the second or third aspect, a plurality of vibrator elements are used as a vibrator.
A defect depth measuring method is provided, wherein a delay circuit is connected to each element, and the refraction angle is finely adjusted by electronic scanning of each element to measure the defect depth.

【0023】請求項5の発明では、請求項1,3または
4のいずれかに記載の欠陥深さ測定方法において、音響
隔離材によって隔離された各振動子をそれぞれ独立的に
使用し、励起のタイミングをそれぞれずらすことによ
り、斜角探傷を同時に行なうことを特徴とする欠陥深さ
測定方法を提供する。
According to a fifth aspect of the present invention, in the defect depth measuring method according to any one of the first to third aspects, each of the vibrators isolated by the acoustic isolating material is used independently, and the excitation Provided is a method for measuring a depth of a defect, characterized in that oblique flaw detection is simultaneously performed by shifting timings.

【0024】請求項6の発明では、同一ケース内に超音
波探傷用振動子を互いに一定の角度で対向する状態で収
納し、これらの振動子間を音響隔離材によって隔離して
構成した超音波探触子と、この超音波探触子を支持する
複数の走査軸を有する走査機構と、前記振動子から被検
査体の表層部周辺に超音波ビームを集中させて発振した
際に計測される超音波の伝搬時間と、発振および受信に
おける超音波入射点間の距離とに基づいて欠陥深さの計
算を行なう演算装置とを備えたことを特徴とする欠陥深
さ測定装置を提供する。
According to the sixth aspect of the present invention, the ultrasonic flaw detecting transducers are housed in the same case so as to face each other at a predetermined angle, and these vibrators are separated from each other by an acoustic isolating material. A probe, a scanning mechanism having a plurality of scanning axes for supporting the ultrasonic probe, and measuring when the ultrasonic beam is concentrated and oscillated from the transducer to the periphery of the surface layer of the test object. Provided is a defect depth measuring device, comprising: a calculating device that calculates a defect depth based on a propagation time of ultrasonic waves and a distance between ultrasonic incident points in oscillation and reception.

【0025】以上の本発明においては、音響隔離材を挟
んで隣接する超音波探触子による超音波入射点を限りな
く接近させ、欠陥先端部からの散乱波または回折波を得
る。そして、入射点間距離、得られた信号の伝搬時間か
ら欠陥深さを測定する。これにより、従来の二振動形探
触子、斜角探触子では為し得なかった表層部および厚さ
の薄い材料の欠陥深さの測定を可能とする。
In the present invention described above, the points of incidence of the ultrasonic waves by the adjacent ultrasonic probes are made as close as possible with the acoustic isolating material interposed therebetween, and scattered or diffracted waves from the tip of the defect are obtained. Then, the defect depth is measured from the distance between the incident points and the propagation time of the obtained signal. As a result, it is possible to measure the depth of a defect in a surface layer portion and a material having a small thickness, which cannot be performed by the conventional dual-vibration probe and the oblique probe.

【0026】なお、本発明においては、欠陥を有する被
検査体の欠陥の深さを測定する超音波探傷法において、
欠陥上に位置した超音波の伝搬径路を、表面から約5m
m以内の領域に設定することが望ましい。すなわち、送
信用超音波探触子および受信用超音波探触子の屈折角が
作る超音波径路の交軸点を表面から5mm以内の領域に
設計する。そして、斜角探触子の場合にはこれらを互い
に向かい合せて斜めに配置し、かつそれらを1つの収納
ケース内に収納し、これにより1mm程度の欠陥につい
ても深さの測定を可能とする。
In the present invention, in the ultrasonic flaw detection method for measuring the depth of a defect in a test object having a defect,
The propagation path of the ultrasonic wave located on the defect is approximately 5 m from the surface.
It is desirable to set the area within m. That is, the intersecting point of the ultrasonic paths formed by the refraction angles of the transmitting ultrasonic probe and the receiving ultrasonic probe is designed in a region within 5 mm from the surface. In the case of the oblique probe, these are arranged obliquely facing each other, and they are stored in one storage case, so that the depth of about 1 mm defect can be measured. .

【0027】ここで、探触子の入射点間距離を短くする
ために、水浸法の適用が考えられるが、水浸法において
は、材料表面からの多重反射等により材料表面から受け
る影響が大きく、初期欠陥の発生する表層部においては
評価できない。
Here, in order to shorten the distance between the incident points of the probe, application of a water immersion method can be considered. It is large and cannot be evaluated in the surface layer where initial defects occur.

【0028】このような理由から水浸法ではなく、接触
法において、超音波の入射点間距離をできるだけ接近さ
せるため、ある角度に傾けた2個の振動子を音響隔離面
で仕切り、一つのケースに納め、超音波主ビームの交軸
点の深さが5mm程度になるように前記探触子間距離を
設計するのである。送信側の超音波探触子から出射され
た超音波は入射後、板厚中に拡散する。表層部に超音波
のエネルギが集中しているため、狙った深さの欠陥を捉
えることができる。ここで、表面波は表面開口欠陥の存
在により遮断されるため、伝搬時間および走査距離の情
報から、欠陥の有無が視覚的に認識でき、非常に有力な
判断基準となる。水浸法では評価ができなかった表層部
に探傷を限定したことにより、欠陥先端部からの信号を
確実に受信することが可能となる。
For this reason, in the contact method instead of the water immersion method, two vibrators inclined at a certain angle are separated by an acoustic isolation surface in order to make the distance between the incident points of ultrasonic waves as close as possible. The distance between the probes is designed so that the probe is housed in a case and the depth of the intersection of the ultrasonic main beam is about 5 mm. The ultrasonic wave emitted from the ultrasonic probe on the transmitting side is diffused into the plate thickness after being incident. Since the energy of the ultrasonic wave is concentrated on the surface layer, a defect at a targeted depth can be captured. Here, since the surface wave is cut off by the presence of the surface aperture defect, the presence or absence of the defect can be visually recognized from the information on the propagation time and the scanning distance, which is a very effective criterion. By limiting the flaw detection to the surface layer that could not be evaluated by the water immersion method, it is possible to reliably receive the signal from the tip of the defect.

【0029】実験的には、1mm深さの欠陥を検出する
ことに成功しており、1mm、2mm、3mm、4m
m、5mmの欠陥に対し、それらの深さを測定した。結
果は、全ての欠陥をすべて検出できる分解能を有し、深
さの測定においてはそれぞれ1mm以下の精度で評価可
能の知見を得た。これにより、初期欠陥の評価を行うこ
とができる。
Experimentally, a defect having a depth of 1 mm has been successfully detected, and 1 mm, 2 mm, 3 mm, 4 m
For m and 5 mm defects, their depth was measured. The results have a resolution capable of detecting all the defects, and have obtained knowledge that can be evaluated with an accuracy of 1 mm or less in depth measurement. Thereby, the initial defect can be evaluated.

【0030】[0030]

【発明の実施の形態】以下、本発明の実施形態につい
て、図1〜図12を参照して説明する。
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

【0031】まず、図2および図3によって、本実施形
態で適用するTOFD法の原理について詳しく説明す
る。図2はTOFD法を実施する場合の概念を示し、図
3は図2に対応した探傷によって得られる典型的な画像
を示している。
First, the principle of the TOFD method applied in the present embodiment will be described in detail with reference to FIGS. FIG. 2 shows the concept of implementing the TOFD method, and FIG. 3 shows a typical image obtained by flaw detection corresponding to FIG.

【0032】図3に示す画像は、信号波形の振幅値を示
すAスコープ表示と、多数のAスコープ表示の信号波形
の振幅値を色の濃淡で表すBスコープ表示とからなる。
送信用超音波探触子3aと受信用超音波探触子3bとの
走査により、入射点間距離を一定として欠陥2を横断さ
せると、送信用超音波探触子3aから出射された超音波
の拡散により、図2に示すように、材料表面を直接伝搬
してくる表面波4、欠陥2の先端部を経由して伝搬して
くる回折波又は散乱波5、および裏面で反射して伝搬し
てくる底面反射波6が、受信用超音波探触子3bによっ
て受信される。ここで、回折波または散乱波5は、欠陥
2の先端部からの超音波伝搬径路の変化により、図3の
Bスコープ表示で示されるように、弓形の画像を形成す
る。欠陥2の先端部では、この回折または散乱現象が発
生しており、欠陥2の先端部が球面波の発生源となり、
受信側へと伝搬してゆくのである。
The image shown in FIG. 3 is composed of an A scope display showing the amplitude values of the signal waveforms, and a B scope display showing the amplitude values of the signal waveforms of many A scope displays by shading of colors.
By scanning the ultrasonic probe for transmission 3a and the ultrasonic probe for reception 3b while keeping the distance between the incident points constant, the ultrasonic wave emitted from the ultrasonic probe for transmission 3a is obtained. As shown in FIG. 2, the surface wave 4 directly propagates on the surface of the material, the diffracted or scattered wave 5 propagated through the tip of the defect 2, and the light reflected and propagated on the back surface. The incoming bottom surface reflected wave 6 is received by the receiving ultrasonic probe 3b. Here, the diffracted wave or the scattered wave 5 forms an arcuate image as shown by the B-scope display in FIG. 3 due to a change in the ultrasonic wave propagation path from the tip of the defect 2. At the tip of the defect 2, this diffraction or scattering phenomenon occurs, and the tip of the defect 2 becomes a generation source of a spherical wave,
It propagates to the receiving side.

【0033】この弓形の頂点が、最短径路で受信された
欠陥先端部からの信号であり、深さ測定の計算に使われ
る。計算式(裏面開口欠陥の場合)は下記の(1)で示
される。
The apex of the bow is the signal from the tip of the defect received on the shortest path and is used for calculating the depth measurement. The calculation formula (in the case of the back surface opening defect) is shown by the following (1).

【0034】[0034]

【数1】 (Equation 1)

【0035】上記の(1)式において、音速c、全伝搬
時間t10+t20および入射点間距離Lが既知である
ので、得られた画像から全伝搬時間tを例えば図3に示
したBスコープのカーソルで計測すれば、欠陥寸法d
が測定可能であることがわかる。図3中のAスコープ表
示はBスコープのカーソル上の波形データを示してお
り、カーソルおよびにより、欠陥先端部および底面
からの信号の伝搬時間を計測することができる。
In the above equation (1), since the sound velocity c, the total propagation time t10 + t20, and the distance L between the incident points are known, the total propagation time t can be calculated from the obtained image using, for example, the cursor of the B scope shown in FIG. Defect size d
Can be measured. The A scope display in FIG. 3 shows waveform data on the cursor of the B scope, and the propagation time of a signal from the tip and the bottom of the defect can be measured using the cursor.

【0036】本実施形態においては、主として以上で説
明したTOFD法を用いる。
In this embodiment, the TOFD method described above is mainly used.

【0037】図1は、本実施形態の方法を実施するため
の装置構成を示す説明図であり、斜角探傷用の超音波探
触子を使用する。
FIG. 1 is an explanatory view showing the structure of an apparatus for carrying out the method of the present embodiment, and uses an ultrasonic probe for oblique flaw detection.

【0038】図1に示すように、本実施形態の超音波探
触子20は、超音波発振用の振動子21aおよび受信用
の振動子21bを互いに一定の角度で対向する状態で、
同一ケース19内に隣接させて収納し、これらの振動子
21a,21b間を音響隔離材23によって隔離して構
成される。
As shown in FIG. 1, an ultrasonic probe 20 according to the present embodiment is configured such that an ultrasonic oscillator 21a and a receiving oscillator 21b face each other at a fixed angle.
The vibrators 21a and 21b are housed adjacent to each other in the same case 19 and are separated by an acoustic isolator 23.

【0039】各振動子21a,21bは、その構成材料
中で表層部近傍に縦波または横波の音波が集中するよう
に適当な角度でくさび24a,24bに密着するように
設計され、それにより各入射点間距離が決定される。各
振動子21a,21bにはコネクタ22a,22bを介
してケーブル26a,26bが接続されている。
Each of the vibrators 21a and 21b is designed so as to be in close contact with the wedges 24a and 24b at an appropriate angle so that longitudinal or transverse acoustic waves are concentrated near the surface layer in the constituent material. The distance between the incident points is determined. Cables 26a and 26b are connected to the transducers 21a and 21b via connectors 22a and 22b.

【0040】また、超音波探触子20を走査する走査機
構31およびその位置を検出する位置検出機構32と、
各振動子21a,21bによる送受信信号の信号処理を
行なう演算装置33と、この演算装置33に連結された
入力装置34および出力装置35とを備える。
Further, a scanning mechanism 31 for scanning the ultrasonic probe 20 and a position detecting mechanism 32 for detecting its position,
An arithmetic unit 33 for performing signal processing of transmission / reception signals by the vibrators 21a and 21b, and an input device 34 and an output device 35 connected to the arithmetic unit 33 are provided.

【0041】そして、超音波探触子20を被検査体とし
ての構造物表層部または薄い断面を有する構造物上で走
査させるとともに、各振動子21a,21bから被検査
体の表層部周辺に超音波ビームを集中させて発振し、微
小な浅い欠陥先端部からの回折波または散乱波を受信し
て、計測される超音波の伝搬時間と発振および受信にお
ける超音波入射点間の距離との関係に基づいて、構造物
表層部または薄い断面を有する構造物の欠陥深さを測定
する。
Then, the ultrasonic probe 20 is scanned on the surface layer of the structure as the object to be inspected or on a structure having a thin section, and the ultrasonic probe 20 is moved from each of the transducers 21a and 21b to the vicinity of the surface layer of the object to be inspected. The relationship between the propagation time of the measured ultrasonic wave and the distance between the ultrasonic wave incident point in oscillation and reception by receiving the diffracted or scattered wave from the tip of the minute shallow defect, oscillating the sound beam and oscillating it. The defect depth of a structure having a surface layer portion or a thin cross section is measured based on the following formula.

【0042】次に、図2〜図8で示した作用説明図によ
り、欠陥深さ測定方法について、詳細に説明する。
Next, the method of measuring the depth of a defect will be described in detail with reference to the operation explanatory views shown in FIGS.

【0043】図4および図5に示すように、音響隔離面
23により仕切られたケース内に送信用と受信用の振動
子21a,21bが組込まれており、各振動子21a,
21bは材料中で表層部近傍に縦波または横波の音波が
集中するように適当な角度でくさび24に密着するよう
に設計され、各入射点間距離が決定される。
As shown in FIGS. 4 and 5, transmitting and receiving vibrators 21a and 21b are incorporated in a case separated by an acoustic isolation surface 23.
Reference numeral 21b is designed so that longitudinal or transverse acoustic waves concentrate on the wedge 24 at an appropriate angle in the material so as to be concentrated near the surface layer, and the distance between the incident points is determined.

【0044】なお、通常では表層部の音波は近距離音場
内にあり、互いに強め合う部分や弱め合う部分が混在し
ており、超音波探傷においては欠陥評価の対象外であっ
た。
Normally, the sound waves in the surface layer are in a near-field sound field, and there are portions that are mutually strengthened and portions that are weakened together, and are not subject to defect evaluation in ultrasonic flaw detection.

【0045】これに対し、本実施形態においては、表面
開口微小欠陥2の存在により、欠陥先端部以外の送信波
は、欠陥で反射されるか、または当たらずにそのまま直
進してしまうかのいずれかであり、欠陥先端部からの回
折波または散乱波5と底面反射波のみ受信される特徴が
ある。
On the other hand, in the present embodiment, due to the presence of the surface opening minute defect 2, the transmitted wave other than the defect tip portion is either reflected by the defect or goes straight without hitting it. In this case, only the diffracted or scattered wave 5 and the bottom reflected wave from the tip of the defect are received.

【0046】欠陥2が存在すれば、欠陥以外の要素たと
えば材料の結晶粒からの疑似エコーや溶接組織等による
疑似エコーがあろうとも必ず、最短時間で帰ってくるの
は欠陥先端部からの信号5であるといえる。これにより
近距離音場内での複雑な領域のほとんどを無視できるの
で、散乱波または回折波5を明瞭に検出することが可能
となるのである。
If the defect 2 is present, even if there is an element other than the defect, for example, a pseudo echo from a crystal grain of a material or a pseudo echo due to a welded structure, the signal returned from the tip of the defect is always returned in the shortest time. It can be said that it is 5. As a result, most of the complicated area in the near field can be ignored, so that the scattered wave or the diffracted wave 5 can be detected clearly.

【0047】欠陥2を横断するように探触子20全体を
走査させると、入射点間距離は一定のままであるので、
欠陥2が入射点間の中央に位置する時に最も振幅が大き
くかつ最短時間で帰ってきた信号である。入射点間の中
央の前後では伝搬径路が長くなり、結局前図のように画
像にすると弓形の画像になる。
When the entire probe 20 is scanned so as to cross the defect 2, the distance between the incident points remains constant.
This signal has the largest amplitude and returns in the shortest time when the defect 2 is located at the center between the incident points. The propagation path becomes long before and after the center between the incident points, so that an image as shown in the previous figure becomes an arcuate image.

【0048】通常のTOFD法においては、超音波の伝
搬距離が長い。しかし、本実施形態の表層部および薄板
材の探傷においては、超音波の伝搬距離が短く、欠陥深
さ測定における計算に誤差を生じ易い。
In the ordinary TOFD method, the propagation distance of the ultrasonic wave is long. However, in the flaw detection of the surface layer portion and the thin plate material according to the present embodiment, the propagation distance of the ultrasonic wave is short, and an error easily occurs in the calculation in the defect depth measurement.

【0049】図7および図8に示すように、振動子21
aから出た超音波は幅を持っており、それぞれ入射点が
異なる。意図した欠陥深さよりも深い場合には、設計点
よりも遠方に入射点はシフトするため、便宜的に振動子
の端部に換算して計算すると、測定精度は向上すること
が後述の図9および図10に示すように、実験により明
確に認められた。これにより、欠陥深さ測定誤差を小さ
く抑えることが可能であり、初期欠陥寸法のモデル化に
貢献することができる。
As shown in FIG. 7 and FIG.
The ultrasonic wave emitted from a has a width and each has a different incident point. When the depth is deeper than the intended defect depth, the incident point shifts farther than the design point. Therefore, if the calculation is performed by converting the value into the end of the vibrator for convenience, the measurement accuracy is improved. As shown in FIG. 10 and FIG. 10, it was clearly recognized by the experiment. As a result, it is possible to reduce the defect depth measurement error and contribute to modeling of the initial defect size.

【0050】以上述べた本実施形態の欠陥深さ測定装置
においては、探触子21a,21bの接近限界距離を小
さくするため、振動子サイズを小さく設計している。そ
のため、下記の(2)式の如く、音波の拡散が大きくな
り、TOFD法として欠陥が捉えやすくなるうえ、材料
表層部においては入射時のビーム幅が狭いため、精度も
向上する。
In the defect depth measuring apparatus of the present embodiment described above, the transducer size is designed to be small in order to reduce the approach limit distance of the probes 21a and 21b. For this reason, as shown in the following equation (2), the diffusion of the sound wave becomes large, so that defects can be easily detected by the TOFD method, and the beam width upon incidence on the surface layer of the material is narrow, so that the accuracy is also improved.

【0051】[0051]

【数2】 (Equation 2)

【0052】図9および図10に本実施形態により得ら
れた欠陥深さ測定結果を示している。図9は厚肉材(厚
さ40mm)における表面開口欠陥(微小欠陥)の寸法
測定結果を示したものである。縦軸に測定結果を示し、
横軸に実際の欠陥深さを示している。本実施形態の結果
では実際の欠陥深さに測定結果が高精度で一致している
ことが分かる。
FIGS. 9 and 10 show the results of measuring the defect depth obtained by the present embodiment. FIG. 9 shows the results of dimensional measurement of surface opening defects (micro defects) in a thick material (thickness: 40 mm). The vertical axis shows the measurement results,
The horizontal axis shows the actual defect depth. It can be seen from the results of the present embodiment that the measurement results match the actual defect depth with high accuracy.

【0053】図10は薄肉材(厚さ10mm)における
表裏面開口欠陥(黒丸印が表面、白丸印が裏面の微小欠
陥)の寸法測定結果を示したものである。前記同様に、
縦軸に測定結果を示し、横軸に実際の欠陥深さを示して
いる。本実施形態の結果においても、実際の欠陥深さに
測定結果が高精度で一致していることが分かる。
FIG. 10 shows the results of measurement of the size of the opening defect on the front and back surfaces (black circles indicate the front surface, white circles indicate the minute defects on the rear surface) of a thin material (thickness: 10 mm). As before,
The vertical axis shows the measurement results, and the horizontal axis shows the actual defect depth. It can also be seen from the results of this embodiment that the measurement results match the actual defect depth with high accuracy.

【0054】なお以上の実施形態においては、振動子2
1をある角度に固定し、設計した入射角で欠陥2の深さ
を測定する手法について説明したが、本発明はそのよう
なものに限られない。
In the above embodiment, the vibrator 2
Although the method of fixing the depth 1 to a certain angle and measuring the depth of the defect 2 at the designed incident angle has been described, the present invention is not limited to such a method.

【0055】すなわち、2組の振動子としてそれぞれ複
数の振動子を集合させたものを使用するとともに、それ
ぞれその要素に遅延回路を接続し、各要素の電子的走査
により屈折角を微調整して欠陥深さ測定を行なうように
してもよい。
That is, a set of a plurality of vibrators is used as two sets of vibrators, and a delay circuit is connected to each element, and the refraction angle is finely adjusted by electronic scanning of each element. Defect depth measurement may be performed.

【0056】例えば図11には、微小な振動子要素を配
列した振動子群により発振側振動子21aおよび受信側
振動子21bを構成した電子走査形の例を示す説明図で
あり、図12は、その作用を示す説明図である。
For example, FIG. 11 is an explanatory diagram showing an example of an electronic scanning type in which the oscillation-side vibrator 21a and the reception-side vibrator 21b are constituted by a vibrator group in which minute vibrator elements are arranged, and FIG. It is explanatory drawing which shows the effect | action.

【0057】本例においては、入射角を固定することな
く、遅延回路25による振動子21a,21bの励起の
タイミングを徐々にずらしていくことにより、超音波の
進行方向を制御するものである。
In this embodiment, the traveling direction of the ultrasonic wave is controlled by gradually shifting the timing of exciting the vibrators 21a and 21b by the delay circuit 25 without fixing the incident angle.

【0058】このように、音響隔離面23に対し、発振
と受信の遅延回路25を対称にし、入射角の変化に伴う
入射点の変化、すなわち入射点間距離を計算すること
で、前述の手法と同様な測定が可能となる。ここで、中
央の音響隔離面23は送信超音波が受信に影響を与えな
いために設けたものである。
As described above, the delay circuit 25 for oscillation and reception is symmetrical with respect to the acoustic isolation surface 23, and the change of the incident point due to the change of the incident angle, that is, the distance between the incident points is calculated. The same measurement as described above can be performed. Here, the central acoustic isolation surface 23 is provided to prevent transmission ultrasonic waves from affecting reception.

【0059】また、上記の遅延回路によるタイミングの
ずれを利用し、それぞれの振動子を別々に使用すること
も可能である。すなわち、TOFD法における送信、受
信の一対の関係ではなく、単独に斜角探触子として使用
するものである。それぞれの振動子が一直線上にきてい
るため、同時の振動子の励起では互いに音波が干渉して
しまう。しかし、励起のタイミングをある間隔だけずら
すことにより、単独の斜角探傷が同時に2方向で行え
る。つまり、音響隔離材によって隔離された各組の振動
子をそれぞれ独立的に使用し、励起のタイミングをそれ
ぞれずらすことにより、斜角探傷を2方向で同時に行な
うようにしてもよい。
Further, it is also possible to use the respective vibrators separately by utilizing the timing shift caused by the delay circuit. That is, instead of a pair of transmission and reception in the TOFD method, it is used independently as an oblique probe. Since the respective vibrators are on a straight line, the sound waves interfere with each other in the simultaneous excitation of the vibrators. However, by shifting the excitation timing by a certain interval, single angle beam inspection can be performed simultaneously in two directions. That is, oblique flaw detection may be performed simultaneously in two directions by independently using each set of transducers isolated by the acoustic isolation material and shifting the excitation timing.

【0060】このような方法によっても、斜角探傷によ
り得られた情報を基に、欠陥の深さ測定モードに切り替
えることにより、より効率の良い探傷を行うことが可能
となる。
According to such a method as well, more efficient flaw detection can be performed by switching to the defect depth measurement mode based on information obtained by oblique flaw detection.

【0061】なお、以上の実施形態では超音波探触子の
振動子を2組に分けた構成としたが、2以上の複数の振
動子を音響隔離材によって隔離配置して構成することも
可能である。
In the above embodiment, the transducers of the ultrasonic probe are divided into two sets. However, two or more transducers may be separated from each other by an acoustic isolation member. It is.

【0062】[0062]

【発明の効果】以上で詳述したように、本発明によれ
ば、欠陥深さを初期の段階で精度良く測定することがで
き、運転プラントにおける圧力容器や構造物等の健全性
の評価、初期欠陥検出による欠陥の進展評価、残存寿命
の推定を行うことができる等、その産業界の品質管理に
与える効果は多大である。
As described in detail above, according to the present invention, it is possible to accurately measure the depth of a defect at an early stage, and to evaluate the soundness of pressure vessels and structures in an operating plant. The effect on the quality control in the industry is enormous, for example, the progress of the defect by the initial defect detection and the estimation of the remaining life can be performed.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明に係る欠陥深さ測定装置の一実施形態に
よるプローブ構成を示す斜視図。
FIG. 1 is a perspective view showing a probe configuration according to an embodiment of a defect depth measuring apparatus according to the present invention.

【図2】前記実施形態に応用するTOFD法の原理を示
す構成および作用説明図。
FIG. 2 is a configuration diagram and operation explanatory diagram showing the principle of the TOFD method applied to the embodiment.

【図3】前記第1実施形態に対応するTOFD法の原理
を示すデータ説明図。
FIG. 3 is a data explanatory view showing the principle of the TOFD method corresponding to the first embodiment.

【図4】前記実施形態による検査状態を示す説明図。FIG. 4 is an explanatory diagram showing an inspection state according to the embodiment.

【図5】図4に示した検査状態における作用を説明する
ための要部拡大図。
FIG. 5 is an enlarged view of a main part for explaining the operation in the inspection state shown in FIG. 4;

【図6】図5に示した検査状態における超音波波形を示
す説明図。
FIG. 6 is an explanatory diagram showing an ultrasonic waveform in the inspection state shown in FIG.

【図7】前記実施形態における超音波の入射点間距離を
示す説明図。
FIG. 7 is an explanatory diagram showing a distance between incident points of ultrasonic waves in the embodiment.

【図8】前記実施形態における補正された超音波入射点
間距離を示す説明図。
FIG. 8 is an explanatory view showing a corrected distance between ultrasonic incident points in the embodiment.

【図9】前記実施形態における一例として厚肉材表面欠
陥の寸法測定結果を示すグラフ。
FIG. 9 is a graph showing a result of measuring a dimension of a surface defect of a thick material as an example in the embodiment.

【図10】前記実施形態による他の例として薄肉材表裏
面欠陥の寸法測定結果を示すグラフ。
FIG. 10 is a graph showing a measurement result of a dimension of a front and back surface defect of a thin material as another example according to the embodiment.

【図11】本発明の他の実施形態による欠陥深さ検出装
置を示す説明図。
FIG. 11 is an explanatory diagram showing a defect depth detection device according to another embodiment of the present invention.

【図12】図11の実施形態による欠陥深さ検出作用を
示す説明図。
FIG. 12 is an explanatory diagram showing a defect depth detecting operation according to the embodiment of FIG. 11;

【図13】従来技術による欠陥深さ検出(端部エコー
法)の一例(裏面検出例)を示す説明図。
FIG. 13 is an explanatory diagram showing an example (backside detection example) of defect depth detection (edge echo method) according to the related art.

【図14】従来技術による欠陥深さ検出(端部エコー
法)の他の例(表面検出例)を示す説明図。
FIG. 14 is an explanatory view showing another example (surface detection example) of the conventional technique for detecting the depth of a defect (edge echo method).

【図15】従来技術による欠陥深さ検出(TOFD法)
の一例(裏面検出例)を示す説明図。
FIG. 15: Defect depth detection (TOFD method) according to the prior art
FIG. 5 is an explanatory diagram showing an example (backside detection example) of FIG.

【図16】従来技術による欠陥深さ検出(TOFD法)
の他の例(厚肉材裏面検出例)を示す説明図。
FIG. 16: Depth depth detection (TOFD method) according to the prior art
Explanatory drawing which shows the other example (example of detection of a thick material rear surface).

【図17】従来技術による欠陥深さ検出(TOFD法)
の一例(厚肉材検出例)を示す説明図。
FIG. 17: Defect depth detection (TOFD method) according to a conventional technique
Explanatory drawing which shows an example (example of detection of thick material).

【図18】従来技術による欠陥深さ検出(TOFD法)
の他の例(薄肉材検出例)を示す説明図。
FIG. 18: Defect depth detection according to the prior art (TOFD method)
Explanatory drawing which shows the other example (example of thin material detection).

【図19】(a),(b)は従来技術による欠陥深さ検
出(表面波法)の一例(厚肉材検出例)原理を示す図。
FIGS. 19A and 19B are diagrams illustrating the principle of an example (example of detecting a thick material) of defect depth detection (surface wave method) according to the related art.

【図20】(a),(b)は従来技術による欠陥深さ検
出(表面波法)の他の例(薄肉材検出例)原理を示す
図。
FIGS. 20A and 20B are diagrams showing the principle of another example (thin material detection example) of defect depth detection (surface wave method) according to the related art.

【符号の説明】[Explanation of symbols]

1 構造物 2 欠陥 3 超音波探触子 4 表面波 5 回折波または散乱波 6 底面反射波 10 欠陥上端からのエコー 11 欠陥コーナーからのエコー 12 欠陥下端からのエコー 19 ケース 20 超音波探触子 21(21a,21b) 振動子 22 コネクタ 23 音響隔離面 24 クサビ 25 遅延回路群 26 ケーブル 31 走査機構 32 位置検出機構 33 演算装置 34 入力装置 35 出力装置 DESCRIPTION OF SYMBOLS 1 Structure 2 Defect 3 Ultrasonic probe 4 Surface wave 5 Diffracted or scattered wave 6 Bottom reflected wave 10 Echo from defect upper end 11 Echo from defect corner 12 Echo from defect lower end 19 Case 20 Ultrasonic probe 21 (21a, 21b) Transducer 22 Connector 23 Acoustic isolation surface 24 Wedge 25 Delay circuit group 26 Cable 31 Scanning mechanism 32 Position detection mechanism 33 Arithmetic unit 34 Input device 35 Output device

Claims (6)

【特許請求の範囲】[Claims] 【請求項1】 複数の超音波探傷用振動子を音響隔離材
によって隔離した状態で隣接配置した超音波探触子を、
被検査体としての構造物表層部または薄い断面を有する
構造物上で走査させるとともに、前記振動子から前記被
検査体の表層部周辺に超音波ビームを集中させて発振
し、微小な浅い欠陥先端部からの回折波または散乱波を
受信して、計測される超音波の伝搬時間と、発振および
受信における超音波入射点間の距離とに基づき、前記構
造物表層部または薄い断面を有する前記被検査体である
構造物の欠陥深さを測定することを特徴とする欠陥深さ
測定方法。
1. An ultrasonic probe which is arranged adjacent to a plurality of ultrasonic test transducers in a state of being separated by an acoustic isolation material,
Scanning is performed on the surface of a structure as a test object or a structure having a thin cross section, and an ultrasonic beam is oscillated from the vibrator around the surface of the test object, oscillating, and the tip of a minute shallow defect Receiving the diffracted or scattered wave from the part, and based on the measured propagation time of the ultrasonic wave and the distance between the ultrasonic incidence points in oscillation and reception, the surface layer of the structure or the object having a thin section. A defect depth measuring method, comprising measuring a defect depth of a structure as an inspection object.
【請求項2】 請求項1記載の欠陥深さ測定方法におい
て、超音波探触子の音響隔離材によって隔離された一方
の振動子を発振側、他方を受信側として使用することを
特徴とする欠陥深さ測定方法。
2. The defect depth measuring method according to claim 1, wherein one of the transducers separated by an acoustic isolator of the ultrasonic probe is used as an oscillation side and the other is used as a reception side. Defect depth measurement method.
【請求項3】 請求項1または2記載の欠陥深さ測定方
法において、超音波入射点間距離を被検査体の板厚変化
に応じて補正し、その補正値を欠陥深さ測定の計算式に
反映させることを特徴とする欠陥深さ測定方法。
3. The defect depth measuring method according to claim 1, wherein the distance between the ultrasonic wave incident points is corrected according to a change in the thickness of the inspection object, and the correction value is used as a calculation formula for measuring the defect depth. A defect depth measurement method characterized by reflecting the defect depth on a defect.
【請求項4】 請求項2又は3記載の欠陥深さ測定方法
において、振動子としてそれぞれ複数の振動子要素を集
合させたものを使用するとともに、それぞれその要素に
遅延回路を接続し、前記各要素の電子的走査により屈折
角を微調整して欠陥深さ測定を行なうことを特徴とする
欠陥深さ測定方法。
4. The defect depth measuring method according to claim 2, wherein a plurality of transducer elements are assembled as a transducer, and a delay circuit is connected to each of the transducer elements. A defect depth measuring method, wherein a refraction angle is finely adjusted by electronic scanning of an element to measure a defect depth.
【請求項5】 請求項1,3または4のいずれかに記載
の欠陥深さ測定方法において、音響隔離材によって隔離
された各振動子をそれぞれ独立的に使用し、励起のタイ
ミングをそれぞれずらすことにより、斜角探傷を同時に
行なうことを特徴とする欠陥深さ測定方法。
5. The defect depth measuring method according to claim 1, wherein each of the vibrators isolated by the acoustic isolator is used independently, and the excitation timing is shifted. Defect depth measurement method characterized by performing angle beam flaw detection at the same time.
【請求項6】 同一ケース内に超音波探傷用振動子を互
いに一定の角度で対向する状態で収納し、これらの振動
子間を音響隔離材によって隔離して構成した超音波探触
子と、この超音波探触子を支持する複数の走査軸を有す
る走査機構と、前記振動子から被検査体の表層部周辺に
超音波ビームを集中させて発振した際に計測される超音
波の伝搬時間と、発振および受信における超音波入射点
間の距離とに基づいて欠陥深さの計算を行なう演算装置
とを備えたことを特徴とする欠陥深さ測定装置。
6. An ultrasonic probe in which ultrasonic transducers for ultrasonic flaw detection are housed in the same case so as to face each other at a certain angle, and these transducers are separated by an acoustic isolation material. A scanning mechanism having a plurality of scanning axes supporting the ultrasonic probe, and a propagation time of ultrasonic waves measured when the ultrasonic beam is concentrated and oscillated from the transducer to the periphery of the surface layer of the object to be inspected. And a calculation device for calculating a defect depth based on a distance between ultrasonic incidence points in oscillation and reception.
JP2000246386A 2000-08-15 2000-08-15 Flaw depth measuring method and its device Pending JP2002062281A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
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Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2000246386A JP2002062281A (en) 2000-08-15 2000-08-15 Flaw depth measuring method and its device

Publications (1)

Publication Number Publication Date
JP2002062281A true JP2002062281A (en) 2002-02-28

Family

ID=18736710

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Country Status (1)

Country Link
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JP2013234886A (en) * 2012-05-08 2013-11-21 Ihi Inspection & Instrumentation Co Ltd Ultrasonic flaw detection method and device by tofd method
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