JP2006138784A - Eddy current flaw detection probe and eddy current flaw detection system - Google Patents

Eddy current flaw detection probe and eddy current flaw detection system Download PDF

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JP2006138784A
JP2006138784A JP2004329970A JP2004329970A JP2006138784A JP 2006138784 A JP2006138784 A JP 2006138784A JP 2004329970 A JP2004329970 A JP 2004329970A JP 2004329970 A JP2004329970 A JP 2004329970A JP 2006138784 A JP2006138784 A JP 2006138784A
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eddy current
flaw detection
current flaw
coil
distance
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Hisashi Endo
久 遠藤
Toshihiko Abe
利彦 阿部
Tetsuya Uchikazu
哲哉 内一
Toshiyuki Takagi
敏行 高木
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Tohoku University NUC
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<P>PROBLEM TO BE SOLVED: To provide an eddy current flaw detection probe for correcting eddy current flaw detection signals caused by the distance and inclination angle between a specimen and a coil by putting noncontact and nonmagnetic distance sensors side by side with the eddy current flaw detection measurement coil and measuring the eddy current flaw detection signals and distance sensor signals simultaneously. <P>SOLUTION: The noncontact and nonmagnetic distance sensors 2 for transmitting and receiving light 3 to and from the eddy current flaw detection coil 1 are put side by side, measure a signal obtained from the distance sensor 2 simultaneously with the eddy current flaw detection signals, correct the eddy current flaw detection signal caused by lift-off, and separate the eddy current flaw detection signal caused by marks and a change 4 in quality. When a plurality of distance sensors 2 are put side by side with the eddy current flaw detection coil 1, the inclination 7 of the coil is calculated by computing a signal obtained by each distance sensor 2, thus correcting the eddy current flaw detection signals precisely. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、原子力発電プラントなどの表面・表層欠陥の検査技術として、非接触で高速な検査が実施できる渦電流探傷試験に用いられる渦電流探傷システムに関し、特に渦電流探傷プローブに関する。   The present invention relates to an eddy current flaw detection system used for an eddy current flaw detection test capable of performing a high-speed inspection without contact as a technique for inspecting surface / surface defects in a nuclear power plant, and more particularly to an eddy current flaw detection probe.

原子力発電プラントなどの表面・表層欠陥の検査技術として、渦電流探傷試験は、非接触で高速な検査が実施できる有力な手法である。加圧水型原子力発電プラントの蒸気発生器伝熱管の検査では、近年の渦電流探傷試験に関する数値シミュレーション技術の大幅な進展を背景に、数値非破壊評価により検査の迅速化・高精度化が達成されている。 As an inspection technique for surface / surface defects in nuclear power plants and the like, the eddy current flaw detection test is a powerful technique that enables high-speed inspection without contact. In the inspection of steam generator tubes in pressurized water nuclear power plants, rapid non-destructive evaluation has achieved rapid and high-precision inspections against the background of significant progress in numerical simulation technology related to eddy current flaw testing in recent years. Yes.

渦電流探傷信号を入力データとして、渦電流場の支配方程式をベースに欠陥形状を計算機上で再現し、欠陥のサイジングをする際、試験対象物−渦電流探傷センサ間の距離、すなわちリフトオフは既知情報である。試験対象の電磁的特性が一定であることを前提に、渦電流探傷信号から直接リフトオフ情報と欠陥情報を分離する方法が提案されている。しかし、検出性と欠陥サイジング評価精度が問題となっている溶接部における応力腐食割れでは、試験対象の電磁的特性が空間的に変化する場合があり、渦電流探傷試験とは異なる方法でリフトオフ計測を実施する必要がある。 Using the eddy current flaw detection signal as input data, the defect shape is reproduced on the computer based on the governing equation of the eddy current field, and when sizing the defect, the distance between the test object and the eddy current flaw detection sensor, that is, the lift-off is known. Information. A method for separating lift-off information and defect information directly from eddy current flaw detection signals has been proposed on the premise that the electromagnetic characteristics of the test object are constant. However, in stress corrosion cracking in welds where detectability and defect sizing evaluation accuracy are problems, the electromagnetic characteristics of the test object may vary spatially, and lift-off measurement is performed using a method different from eddy current testing. It is necessary to carry out.

従来、渦電流探傷プローブは1個ないしは数個を組み合わせたコイルから構成されていた。渦電流探傷法は表面近傍の金属のきずや材質に応じた渦電流探傷信号を検出する方法なので、被検体の表面形状のためにコイルが傾いて信号出力が変化するという問題があった。 Conventionally, eddy current flaw detection probes have been composed of one or a combination of several coils. The eddy current flaw detection method is a method for detecting an eddy current flaw detection signal corresponding to a metal flaw or material in the vicinity of the surface. Therefore, there has been a problem that the signal output changes because the coil is inclined due to the surface shape of the subject.

このような技術は、例えば非特許文献1に開示されている。非特許文献1に開示された方法は、あらかじめ数値解析で求めたデータベースを用いて渦電流探傷信号の信号強度と位相情報からプローブと被検体間の距離を推定可能であるが、被検体の材質の変化ときずが混在したときの問題を解決できていない。   Such a technique is disclosed in Non-Patent Document 1, for example. The method disclosed in Non-Patent Document 1 can estimate the distance between the probe and the subject from the signal intensity and phase information of the eddy current flaw detection signal using a database obtained in advance by numerical analysis. The problem of mixed changes of time cannot be solved.

上記のように従来の技術では、被検体に対してコイルが傾いたり被検体に凹凸があると信号出力が減少或いは増大するという問題があった。換言すれば、渦電流探傷法は表面近傍の金属のきずや材質に応じた渦電流探傷信号を検出する方法なので、被検体の表面形状のためにコイルが傾いて信号出力が変化すると、きずによって生じる信号の変化と区別が困難であるという問題を有している。 As described above, the conventional technique has a problem that the signal output decreases or increases when the coil is inclined with respect to the subject or the subject has irregularities. In other words, the eddy current flaw detection method is a method for detecting eddy current flaw detection signals according to metal flaws and materials in the vicinity of the surface. It has the problem that it is difficult to distinguish from the change in the signal that occurs.

また、特許文献1および2には、渦電流探傷試験においてリフトオフ信号を除去する方法について記載されているが、本発明のようにリフトオフ情報そのものを積極的に利用して検査精度、信頼性の向上を図るものではない。 Patent Documents 1 and 2 describe a method for removing a lift-off signal in an eddy current flaw test. However, as in the present invention, the lift-off information itself is actively used to improve inspection accuracy and reliability. Is not intended.

International Journal of Fatigue、第23巻(2001年)、S477−S485頁International Journal of Fatage, Vol. 23 (2001), S477-S485 特開平10−197493号公報JP-A-10-197493 特開平10−111279号公報Japanese Patent Laid-Open No. 10-111279

本発明は、非接触かつ非磁性の距離センサを渦電流探傷測定コイルに併設し、渦電流探傷信号と距離センサ信号を同時に計測することで被検体とコイルとの距離および傾斜角に起因する渦電流探傷信号を補正する渦電流探傷プローブを提供することを課題としている。   In the present invention, a non-contact and non-magnetic distance sensor is provided in an eddy current flaw measuring coil, and an eddy current caused by the distance and inclination angle between the subject and the coil is measured by simultaneously measuring the eddy current flaw detection signal and the distance sensor signal. An object of the present invention is to provide an eddy current flaw detection probe that corrects a current flaw detection signal.

上記課題を解決するための手段として、本発明は以下の特徴を有している。
請求項1に記載の渦電流探傷プローブでは、前記渦電流プローブは、光を送受信する非磁性の距離センサを渦電流探傷測定コイルに併設し、前記距離センサが受信する被検体との距離信号によって渦電流探傷信号を補正することを特徴とする。
請求項2に記載の渦電流探傷プローブでは、さらに、前記渦電流探傷プローブは、複数個の前記距離センサによって被検体とコイルとの傾斜角を補正することを特徴とする。
請求項3に記載の渦電流探傷プローブでは、さらに、前記渦電流探傷プローブは、光センサの信号を光ファイバーによって送受信することを特徴とする渦電流探傷プローブ。
請求項4に記載の渦電流計測システムでは、表面・表層欠陥の検査技術として、渦電流探傷プローブを用いた数値非破壊評価により非接触で高速な検査を行う渦電流計測システムにおいて、前記計測システムは、請求項1ないし3のいずれかに記載の渦電流探傷プローブを用いることを特徴とする。
As means for solving the above problems, the present invention has the following features.
The eddy current flaw detection probe according to claim 1, wherein the eddy current probe includes a nonmagnetic distance sensor that transmits and receives light in an eddy current flaw measurement coil, and the distance signal from the object received by the distance sensor The eddy current flaw detection signal is corrected.
The eddy current flaw detection probe according to claim 2 is characterized in that the eddy current flaw detection probe corrects an inclination angle between the subject and the coil by the plurality of distance sensors.
4. The eddy current flaw probe according to claim 3, wherein the eddy current flaw probe further transmits and receives a signal of an optical sensor through an optical fiber.
5. The eddy current measurement system according to claim 4, wherein as the surface / surface layer defect inspection technique, the non-contact high-speed inspection is performed by numerical nondestructive evaluation using an eddy current flaw probe, the measurement system Is characterized in that the eddy current flaw detection probe according to any one of claims 1 to 3 is used.

本発明によれば、渦電流探傷法において常に問題となる被検体と渦電流コイルとの距離変化、及びコイルの傾きを光センサによって検知して、補正したので渦電流探傷法による非破壊検査の精度、信頼性を向上できるという効果が得られる。 According to the present invention, the change in the distance between the subject and the eddy current coil, which is always a problem in the eddy current flaw detection method, and the inclination of the coil are detected and corrected by the optical sensor. The effect that accuracy and reliability can be improved is obtained.

本発明の実施の形態は、光ファイバーによって被検体表面を照明し、その反射光強度を測定する光センサ1個ないし数個を渦電流探傷測定用のコイルとを一体化した渦電流探傷プローブである。以下、図面を参照しながら説明する。 The embodiment of the present invention is an eddy current flaw detection probe in which one or several optical sensors that illuminate the surface of a subject with an optical fiber and measure the intensity of reflected light are integrated with a coil for eddy current flaw measurement. . Hereinafter, description will be given with reference to the drawings.

図1は本発明の実施の形態による渦電流探傷プローブの概略図で、(a)は本発明による渦電流探傷プローブの実施イメージ、(b)は渦電流探傷コイル1と被検体5との距離が変化時の図、(c)は、渦電流探傷コイル1と被検体5との間に傾斜ができたときの図である。渦電流探傷コイル1に光3を送受信する非接触かつ非磁性の距離センサ2を併設し、距離センサ2より得られる信号を渦電流探傷信号と同時計測することにより、リフトオフに起因する渦電流探傷信号を補正し、きずや材質の変化4に起因する渦電流探傷信号とを分離する。   1A and 1B are schematic views of an eddy current flaw detection probe according to an embodiment of the present invention. FIG. 1A is an image of an eddy current flaw detection probe according to the present invention, and FIG. 1B is a distance between an eddy current flaw detection coil 1 and a subject 5. (C) is a view when an inclination is made between the eddy current flaw detection coil 1 and the subject 5. The eddy current flaw detection coil 1 is provided with a non-contact and non-magnetic distance sensor 2 that transmits and receives light 3, and the signal obtained from the distance sensor 2 is simultaneously measured with the eddy current flaw detection signal, so that the eddy current flaw caused by lift-off is detected. The signal is corrected, and the eddy current flaw detection signal caused by the flaw or material change 4 is separated.

ここで、リフトオフ6とは、渦電流探傷コイル1と被検体5との距離を意味し、従来の渦電流探傷試験ではコイルの傾き7もリフトオフ6として表現されていた。 Here, the lift-off 6 means the distance between the eddy current flaw detection coil 1 and the subject 5, and the inclination 7 of the coil is also expressed as the lift-off 6 in the conventional eddy current flaw detection test.

図1(b)、(c)を参照すると、渦電流探傷コイル1に併設する距離センサ2を複数にした場合、各距離センサ2で得られる信号の演算でコイルの傾き7を算出することができ、高精度な渦電流探傷信号の補正が可能である。 Referring to FIGS. 1B and 1C, when a plurality of distance sensors 2 are provided adjacent to the eddy current flaw detection coil 1, the coil inclination 7 can be calculated by calculating a signal obtained from each distance sensor 2. It is possible to correct the eddy current flaw detection signal with high accuracy.

図2は距離センサ2として用いる光センサの概略図である。光源11から発せられた光は、光ファイバー通じて送信され、ハーフミラー9で反射し、レンズ10によって光を集束すると、光スポットの面積が最小となる焦点12の位置において光スポット単位面積当たりの明るさは最大となる。また、焦点12からの距離が増すにつれて単位面積当たりの明るさは減少する。従って、集束された光スポットの明るさを測定することによりレンズと被検体の距離を測定できる。スポットの明るさは反射光13としてハーフミラー9を透過し、光ファイバーを通して受光体8で受信され、渦電流探傷コイル1と被検体5との距離の信号に変換され、渦電流探傷信号の補正に用いられる。 FIG. 2 is a schematic view of an optical sensor used as the distance sensor 2. The light emitted from the light source 11 is transmitted through the optical fiber, reflected by the half mirror 9, and when the light is focused by the lens 10, the brightness per unit area of the light spot at the position of the focal point 12 where the area of the light spot is minimized. The maximum is. Further, the brightness per unit area decreases as the distance from the focal point 12 increases. Therefore, the distance between the lens and the subject can be measured by measuring the brightness of the focused light spot. The brightness of the spot passes through the half mirror 9 as reflected light 13, is received by the photoreceptor 8 through the optical fiber, is converted into a signal of the distance between the eddy current flaw detection coil 1 and the subject 5, and is used to correct the eddy current flaw detection signal. Used.

ここでハーフミラー9、レンズ10、光源11は、必要とされるリフトオフ計測範囲に応じて適宜選択することで焦点12の位置、反射光13の強度を変更できるとことはいうまでもない。 Here, it goes without saying that the position of the focal point 12 and the intensity of the reflected light 13 can be changed by appropriately selecting the half mirror 9, the lens 10, and the light source 11 according to the required lift-off measurement range.

本発明に係る渦電流探傷プローブは、金属構造物欠陥の非破壊検査や金属材料特性測定等の様々な分野に適用できる。   The eddy current flaw detection probe according to the present invention can be applied to various fields such as nondestructive inspection of metal structure defects and measurement of metal material characteristics.

本発明の渦電流探傷システムの概念図を図3に示す。本発明に係る距離センサ組み込み型渦電流探傷プローブを用いたリフトオフ同時計測により得られた渦電流探傷信号とリフトオフ信号をパラメータにした評価により、欠陥サイジング精度向上が可能となる。 A conceptual diagram of the eddy current flaw detection system of the present invention is shown in FIG. Defect sizing accuracy can be improved by evaluation using the eddy current flaw detection signal and liftoff signal obtained by simultaneous lift-off measurement using the eddy current flaw detection probe incorporating the distance sensor according to the present invention as parameters.

本発明の実施の形態による渦電流探傷プローブの概略図である。It is the schematic of the eddy current test probe by embodiment of this invention. 距離センサとして用いる光センサの距離計測の概略図である。It is the schematic of distance measurement of the optical sensor used as a distance sensor. 本発明の渦電流探傷システムの概念図である。It is a conceptual diagram of the eddy current flaw detection system of this invention.

符号の説明Explanation of symbols

1 渦電流探傷コイル
2 距離センサ
3 光
4 きずや材質の変化
5 被検体
6 リフトオフ
7 コイルの傾き
8 受光体
9 ハーフミラー
10 レンズ
11 光源
12 焦点
13 反射光
DESCRIPTION OF SYMBOLS 1 Eddy current flaw detection coil 2 Distance sensor 3 Light 4 Scratch and material change 5 Subject 6 Lift-off 7 Coil inclination 8 Photoreceptor 9 Half mirror 10 Lens 11 Light source 12 Focus 13 Reflected light

Claims (4)

光を送受信する非磁性の距離センサを渦電流探傷測定コイルに併設し、前記距離センサが受信する被検体との距離信号によって渦電流探傷信号を補正する
ことを特徴とする渦電流探傷プローブ。
An eddy current flaw detection probe comprising: a non-magnetic distance sensor that transmits and receives light; and an eddy current flaw detection measurement coil that corrects an eddy current flaw detection signal based on a distance signal from a subject received by the distance sensor.
請求項1に記載の渦電流探傷プローブにおいて、
前記渦電流探傷プローブは、複数個の前記距離センサによって被検体とコイルとの傾斜角を補正する
ことを特徴とする渦電流探傷プローブ。
The eddy current flaw detection probe according to claim 1,
The eddy current flaw detection probe corrects an inclination angle between a subject and a coil by a plurality of the distance sensors.
請求項1または2に記載の渦電流探傷プローブにおいて、
前記渦電流探傷プローブは、光センサの信号を光ファイバーによって送受信する
ことを特徴とする渦電流探傷プローブ。
The eddy current flaw detection probe according to claim 1 or 2,
The eddy current flaw detection probe transmits and receives an optical sensor signal through an optical fiber.
表面・表層欠陥の検査技術として、渦電流探傷プローブを用いた数値非破壊評価により非接触で高速な検査を行う渦電流計測システムにおいて、
前記計測システムは、請求項1ないし3のいずれかに記載の渦電流探傷プローブを用いる
ことを特徴とする渦電流計測システム。
As an inspection technology for surface / surface defects, in an eddy current measurement system that performs non-contact high-speed inspection by numerical nondestructive evaluation using an eddy current flaw probe,
The eddy current measurement system using the eddy current flaw detection probe according to any one of claims 1 to 3.
JP2004329970A 2004-11-15 2004-11-15 Eddy current flaw detection probe and eddy current flaw detection system Pending JP2006138784A (en)

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CN103076390A (en) * 2012-12-27 2013-05-01 佛山市斯派利管业科技有限公司 Positioning method and device applied to eddy current flaw detection, and eddy current flaw detector
JP2017194404A (en) * 2016-04-22 2017-10-26 横河電機株式会社 Thickness reduction detection system, and thickness reduction detection method
KR20190024986A (en) * 2016-07-01 2019-03-08 일리노이즈 툴 워크스 인코포레이티드 Integrated system and method for in-situ 3-axis scanning and detection of defects in objects subject to static and periodic testing
JP2019527820A (en) * 2016-07-01 2019-10-03 イリノイ トゥール ワークス インコーポレイティド Integrated system and method for in-situ three-axis scanning and detection of defects in an object under static and repeated tests
KR102353788B1 (en) 2016-07-01 2022-01-19 일리노이즈 툴 워크스 인코포레이티드 Integrated system and method for in situ 3-axis scanning and detection of defects in objects subjected to static and periodic testing

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