JPS59166859A - Eddy current flaw detector for pipe provided with interpolating coil - Google Patents

Abstract

PURPOSE:To output a signal having a good correlativity against a phase of a defect signal by providing a signal converting circuit for indicating a defect and operating cos theta or sin theta/2 basing on an (x) component and a (y) component of a vector signal of phase theta. CONSTITUTION:An amplitude A of a defect signal by an (x) component and a (y) component of a defect signal is derived by an expression I . Also, costheta and sintheta/2 are derived by an expression II and an expression III, respectively. A defect detecting part 1 consists of a detecting coil 2 inserted into a pipe P to be tested, an oscillating circuit, a bridge circuit, and amplifier, etc., and a variation of the impedance of the detecting coil, which is varied in accordance with size of a defect is outputted as a defect signal. A signal converting part 11 derives the amplitude A, costheta and sintheta/2 by operating and processing a signal (x) and (y) from the defect detecting part 1. An output part 21 consists of gate circuits 22, 23 and indicating devices 24, 25 and 26, and when the amplitude A becomes a prescribed value (a value above a noise level), a signal costheta and a signal sintheta/2 are outputted to the indicating devices 25, 26. According to this system, costheta or sintheta/2 is operated, therefore, the flaw detecting work is executed efficiently, and also automated easily.

Description

【発明の詳細な説明】 この発明は内挿コイルを備えた管用渦流探傷装置に関す
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an eddy current flaw detection device for pipes equipped with an interpolated coil.

渦流探傷法では一般に材料中の欠陥は検出コイルのイン
ピーダンス変化として検出される。渦流探傷器は抵抗分
および誘導分よりなるベクトルの欠陥信号を出力する。In the eddy current flaw detection method, defects in the material are generally detected as changes in the impedance of the detection coil. An eddy current flaw detector outputs a vector defect signal consisting of a resistive component and an inductive component.

内挿コイルを用いた管の渦流探傷法では、欠陥信号の振
幅は欠陥の深さだけではなく、欠陥の断面積にも依存す
るので、浅い欠陥でも開口面積が太きいときには振幅も
大きくなる。したがって、１チヤンネル式記録の信号光
示、すなわち振幅のみ全表示する方法では正確に欠陥の
深さを知ることはできない。In tube eddy current testing using an interpolated coil, the amplitude of the defect signal depends not only on the depth of the defect but also on the cross-sectional area of the defect, so even if the defect is shallow, the amplitude will be large when the opening area is large. Therefore, the depth of the defect cannot be accurately determined by the signal light display of one channel recording, that is, by displaying only the amplitude in its entirety.

一方、欠陥の深さは欠陥信号の位相によく対応すること
が知られている。Ｊまた、ＡＳＭＥ　（米国機械学会）
の規格には欠陥信号の位相によって欠陥の深さを検出す
ることが規定されている。欠陥信号の位相は試験周波数
によって大きく変化するが、上記規定ではリフトオフな
どによる雑音信号の位相を０、すなわち雑音信号はＸ軸
上に現われるようにしたとき、標準試験片の貫通ドリル
穴に対する位相が１３５度となるように試験周波数を選
定することになっている。この場合、欠陥信号の位相は
０〜１８０度の範囲内で変化する。On the other hand, it is known that the depth of a defect corresponds well to the phase of the defect signal. JAlso, ASME (American Society of Mechanical Engineers)
The standard stipulates that the depth of a defect is detected based on the phase of the defect signal. The phase of the defect signal varies greatly depending on the test frequency, but in the above regulations, when the phase of the noise signal due to lift-off etc. is set to 0, that is, the noise signal appears on the X axis, the phase with respect to the through drill hole of the standard test piece is The test frequency is to be selected so that the angle is 135 degrees. In this case, the phase of the defect signal varies within a range of 0 to 180 degrees.

従来、２チャンネル式渦流探傷器の二つの出力信号（振
幅Ｘおよびｙ）をＸ−ＹレコーダのチャートあるいはＣ
ＲＴの画面から読み取り、これに基づいて欠陥信号の位
相θの一〇を計算していた。Conventionally, the two output signals (amplitudes X and y) of a two-channel eddy current flaw detector were recorded on the chart of an
The phase θ of the defect signal was calculated based on the reading from the RT screen.

そして、位相θの代りにこの一〇により欠陥の深さを求
めていた。しかし、この方法では振幅Ｘおよびｙの読取
り、−θの計算などに多くの手間を要し、探傷作業の能
率低下の一因となっていた。Then, instead of the phase θ, the depth of the defect was determined using this 10. However, this method requires a lot of time and effort to read the amplitudes X and y, calculate -θ, etc., which is one of the causes of a decrease in the efficiency of flaw detection work.

１だ、−θは９０度近くで非常に大きな値となるので、
これにより欠陥の深さを求めることは困難であった。1, since -θ becomes a very large value near 90 degrees,
This made it difficult to determine the depth of the defect.

この発明は内挿コイルを用いた管の渦流探傷における上
記のような問題を解決するためになされたもので、欠陥
信号の位相に対し良好な相関性をもった信号を出力する
渦流探傷装置を提供しようさするものである。This invention was made in order to solve the above-mentioned problems in eddy current flaw detection of tubes using an interpolation coil, and it is an eddy current flaw detection device that outputs a signal that has good correlation with the phase of a defect signal. This is what we are trying to provide.

この発明の管用渦流探傷装置は欠陥を指示する、位相θ
のベクトル信号のＸ成分およびＸ成分（こ基づいて所θ
またはｓｉｎθ／／２を演算する信号変換回路を備えて
いる。The eddy current flaw detection device for pipes of this invention indicates a defect, and the phase θ
The X component and the X component of the vector signal (based on this, θ
Alternatively, it is provided with a signal conversion circuit that calculates sin θ//2.

この発明では瀉θ捷たはｓｉｎθ／／２を演算し、これ
を出力するので、従来のようにＸ−Ｙレコーダあるいは
ＣＲＴから欠陥信号のＸ成分およびＸ成分を読み取る必
要はなく、丑だ読み取ったＸ成分およＱｙＸ成分ら一〇
を求める計算も不要である。したがって、探傷作業は能
率的となり、自動化も容易となる。゛さらに、邸θまた
はＳ石θ／２は位相θの変域内（０〜１８０度）で連続
的に変化するので、房θまたはｍθ／２から欠陥の深さ
を正確に求めることができる。In this invention, since the θ value or sin θ//2 is calculated and outputted, there is no need to read the X component and the X component of the defective signal from an X-Y recorder or CRT as in the past. There is no need to calculate the X component, QyX component, etc. Therefore, flaw detection work becomes efficient and automation becomes easy. Furthermore, since the height θ or the S-stone θ/2 changes continuously within the range of the phase θ (0 to 180 degrees), the depth of the defect can be accurately determined from the cluster θ or mθ/2.

以下、この発明を実施例に基づき詳細に説明する。Hereinafter, this invention will be explained in detail based on examples.

欠陥信号のＸ成分およびＸ成分により欠陥信号の振幅Ａ
は次の式（１）によって求められる。The amplitude A of the defect signal is determined by the X and X components of the defect signal.
is determined by the following equation (1).

Ａ　＝　Ａ乙閣　　　　・・（１） また、邸θおよびｓｉｎθ／２はそれぞれ邸θ−ｘ／ｆ
ｉ　　　・・・・・・・（２）ＳＬｎ０／２−Ｘ７司「
］）／　２２　、、、、、、　（３）によって求められ
る。A = Aokaku ... (1) Also, residence θ and sin θ/2 are respectively residence θ-x/f
i ・・・・・・(2) SLn0/2-X7 Tsukasa
])/22 , , , , It is obtained by (3).

第１図は上記式（１１〜（３）の演算を実行する回路を
含むこの発明の装置の一例を示すもので、装置のブロッ
ク図である。FIG. 1 is a block diagram showing an example of the device of the present invention including a circuit that executes the calculations of the above equations (11 to (3)).

管用渦流探傷装置は欠陥検出部１．信号変換部１１およ
び出力部２１よりなっている。Eddy current flaw detection equipment for pipes has a defect detection section 1. It consists of a signal conversion section 11 and an output section 21.

欠陥検出部１は被試験管Ｐ内に挿入される検出コイル２
、発振回路、ブリッジ回路、増幅器等（いずれも図示し
ない）からなり、公知の渦流探傷装置の本体と同様の構
成である。欠陥検出部１は欠陥の大きさにより変化する
検出コイル２のインピーダンスの変化を欠陥信号として
出力する。欠陥信号はＸ成分およびＸ成分とからなるベ
クトル信号である。The defect detection section 1 includes a detection coil 2 inserted into the test tube P.
, an oscillation circuit, a bridge circuit, an amplifier, etc. (all not shown), and has the same structure as the main body of a known eddy current flaw detection device. The defect detection section 1 outputs a change in the impedance of the detection coil 2, which changes depending on the size of the defect, as a defect signal. The defect signal is a vector signal consisting of an X component and an X component.

信号変換部１１は欠陥検出部１からの信号Ｘおよびｙを
演算処理して振幅Ａ、ＣＯＳθおよび癲θ／２を求める
。すなわち、信号変換部１１は２乗口路１２゜１３を備
えており、欠陥検出部１からの信号Ｘおよびｙを２乗す
る。２乗口路１２　、　、１３には加算回路１４および
平方根回路１５が順次接続されており、平方根回路１５
から振幅Ａが出力される。また、信号変換部１１は欠陥
検出部１から信号ｘ５上記平方根回路１５から振幅Ａが
入力される除算回路１６ヲ備えている。除算回路１６は
除算ＸＡを行い、房θを求める。信号変換部１１はまた
減算回路１７を有している。The signal conversion section 11 performs arithmetic processing on the signals X and y from the defect detection section 1 to obtain amplitude A, COS θ, and amplitude θ/2. That is, the signal converter 11 is provided with a square path 12.degree. 13, and squares the signals X and y from the defect detector 1. An adder circuit 14 and a square root circuit 15 are sequentially connected to the square root circuits 12 , , 13 .
An amplitude A is output from. The signal conversion section 11 also includes a division circuit 16 into which the signal x from the defect detection section 1 and the amplitude A from the square root circuit 15 are input. The division circuit 16 performs division XA to obtain the tuft θ. The signal conversion section 11 also has a subtraction circuit 17.

減算回路１７には欠陥検出部１からの信号Ｘ５平方根回
路１５からの振幅Ａが入力され、両者の差（Ａ−ｘ）が
求められる。減算回路１７には除算回路１８が接続され
ており、除算回路１８は平方根回路１９がら振幅Ａが入
力され、商（Ａ−Ｘ）／Ａを求める。・除算回路１８に
続いて平方根回路１９および定数倍回路加が順次設けら
れている。平方根回路１９はＶイに悪Σ臥を求め、定数
倍回路加はこれを１冷σ倍してｓｉｎ　’１２を出力す
る。The signal X5 from the defect detection section 1 and the amplitude A from the square root circuit 15 are input to the subtraction circuit 17, and the difference (A-x) between the two is determined. A division circuit 18 is connected to the subtraction circuit 17, and the division circuit 18 receives the amplitude A from the square root circuit 19 and calculates the quotient (A-X)/A. - Following the division circuit 18, a square root circuit 19 and a constant multiplication circuit are sequentially provided. The square root circuit 19 obtains the negative ΣΣ for V, and the constant multiplier adds this by 1 cold σ and outputs sin '12.

出力部２１はゲート回路２２．２３および指示装置２４
゜５．２６よりなっている。ゲート回路２２．２３はゲ
ート信号として前記平方根回路１５がら振幅Ａが入力さ
れ、振幅Ａが所定の値（雑音レベル以上の値）となった
とき除算回路１６からの信号部θおよび定数倍回路２０
からの信号部θ／２を指示装置５，２６に出力する。指
示装置２４は振幅Ａを表示する。The output section 21 includes gate circuits 22, 23 and an indicating device 24.
It is from ゜5.26. The gate circuits 22 and 23 receive the amplitude A from the square root circuit 15 as a gate signal, and when the amplitude A reaches a predetermined value (a value higher than the noise level), the signal section θ from the division circuit 16 and the constant multiplier circuit 20 are input.
The signal portion θ/2 from the input signal θ/2 is outputted to the indicating device 5, 26. The indicating device 24 displays the amplitude A.

つぎに、上記装置による実験例について説明する。Next, an experimental example using the above device will be explained.

実験に用いた試験品は外径３２ｍｍ、　　肉厚１５間の
アルミニウム管に人工欠陥（平底ドリル穴および円周溝
）７ｉ−ＡＳＭＥの規格に基づき加工したものである。The test piece used in the experiment was an aluminum tube with an outer diameter of 32 mm and a wall thickness of 15 mm, which was machined with artificial defects (flat bottom drill hole and circumferential groove) according to the 7i-ASME standard.

検出コイルは外径２４■１幅２圏の円周溝に０．１圏φ
のエナメル線を１１０タ一ン巻いたもので、２個の検出
コイルを中心間隔６門をおいて配置した。試験周波数は
８ＫＪ−１ｚで、貫通ドリル穴に対する信号の位相は１
３３度であった。検出コイルは管内を０．２１６　’Ｉ
’！／Ｓの速度で移動した。The detection coil has an outer diameter of 24 mm, a width of 2 circles, and a circumferential groove with a diameter of 0.1 mm.
Enameled wire was wound with 110 turns, and two detection coils were arranged with a center spacing of 6 gates. The test frequency is 8KJ-1z and the signal phase for the through drill hole is 1
It was 33 degrees. The detection coil moves inside the tube at 0.216'I
'! Moved at a speed of /S.

第２図は実験結果を示すもので、曲線ａは信号部θを、
曲線すは信号ｓｉｎθ／２を示している。、信号部θお
よびｓｉｎθ／２はそれぞれ欠陥の深さに対応し連続的
に変化しており、これらの信号から欠陥の深さを知るこ
とができる。両凸Ｈａおよびｂを比較すると明らかなよ
うに、出力信号部θは出力信号ｓｉｎθ／２よりも欠陥
の深さに対し大きく変化するので、前者による方が高い
精度で欠陥の深さを求めることができる。一方、雑音信
号の位相が０となるように試験周波数を選んだ場合、出
力信号ｓｉｎθ／２は雑音信号のとき０（！：なり、欠
陥とリフトオフなどとを弁別することができる。Figure 2 shows the experimental results, where curve a represents the signal part θ,
The curve shows the signal sin θ/2. , signal portion θ and sin θ/2 change continuously corresponding to the depth of the defect, and the depth of the defect can be known from these signals. As is clear from comparing the biconvex Ha and b, the output signal part θ changes more with respect to the depth of the defect than the output signal sin θ/2, so the former allows determining the depth of the defect with higher accuracy. I can do it. On the other hand, if the test frequency is selected so that the phase of the noise signal is 0, the output signal sin θ/2 becomes 0 (!:) when it is a noise signal, and it is possible to discriminate between defects and lift-off.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図はこの発明の装置の一例を示すブロック図、およ
び第２図は上記装置による実験例を示すもので、欠陥の
深さと信号幅θおよびｓｉｎθ／２との関係を示すグラ
フである。 １・・・欠陥検出部、２・・・検出コイ／し、１１・・
・信号変換部、１２．１．３・・・２乗回路、工４・・
・力ロ算回路、１５．１９・・・平方根回路、１６．１
８・・・除算回路、１７・・・減算回路、２０・・・定
数倍回路、２１・・・出力部、２２．２３・・・ゲート
回路、２４．２５．２６・・・指示装置、Ｐ・・・被試
験管。 特許出願人　代理人 弁理士　矢　葺　知　之 （ほか１名）FIG. 1 is a block diagram showing an example of the apparatus of the present invention, and FIG. 2 shows an experimental example using the above apparatus, and is a graph showing the relationship between the depth of a defect and the signal width θ and sin θ/2. DESCRIPTION OF SYMBOLS 1... Defect detection part, 2... Detection coil/shi, 11...
・Signal converter, 12.1.3... Square circuit, Engineering 4...
・Power rho arithmetic circuit, 15.19...Square root circuit, 16.1
8... Division circuit, 17... Subtraction circuit, 20... Constant multiplier circuit, 21... Output section, 22.23... Gate circuit, 24.25.26... Indication device, P ...Test tube. Patent applicant Representative patent attorney Tomoyuki Yafuki (and 1 other person)

Claims (1)

【特許請求の範囲】[Claims] 欠陥を指示する、位相θのベクトル信号のＸ成分および
Ｘ成分に基づいて邸θまたはｓＩｎθ／２を演算する信
号変換回路を有することを特徴とする内挿コイルを備え
た管用渦流探傷装置。What is claimed is: 1. An eddy current flaw detection device for pipes equipped with an interpolation coil, characterized by having a signal conversion circuit that calculates θ or sInθ/2 based on the X component and the X component of a vector signal of phase θ, which indicates a defect.