JPH0125019B2 - - Google Patents
Info
- Publication number
- JPH0125019B2 JPH0125019B2 JP56118540A JP11854081A JPH0125019B2 JP H0125019 B2 JPH0125019 B2 JP H0125019B2 JP 56118540 A JP56118540 A JP 56118540A JP 11854081 A JP11854081 A JP 11854081A JP H0125019 B2 JPH0125019 B2 JP H0125019B2
- Authority
- JP
- Japan
- Prior art keywords
- primary coil
- inspected
- frequency
- flaw detection
- signal
- 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.)
- Expired
Links
- 238000001514 detection method Methods 0.000 claims description 41
- 239000000463 material Substances 0.000 claims description 32
- 230000007547 defect Effects 0.000 claims description 9
- 239000000523 sample Substances 0.000 claims description 4
- 230000003111 delayed effect Effects 0.000 claims 2
- 230000001360 synchronised effect Effects 0.000 description 13
- 238000005070 sampling Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 6
- 230000035945 sensitivity Effects 0.000 description 3
- 230000004907 flux Effects 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 239000011162 core material Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000006249 magnetic particle Substances 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
- G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
- G01N27/90—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents
- G01N27/9046—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents by analysing electrical signals
Description
【発明の詳細な説明】
この発明は、渦流探傷法、特に、大面積の被検
査材の探傷を容易に行うことができる渦流探傷法
に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an eddy current flaw detection method, and particularly to an eddy current flaw detection method that can easily perform flaw detection on a large area of a material to be inspected.
従来から行われている渦流探傷法としては、磁
紛探傷法や渦電流を利用した渦流探傷法がある。 Conventional eddy current flaw detection methods include magnetic particle flaw detection and eddy current flaw detection using eddy current.
図面を参照しながら、従来の渦流探傷法につい
て説明する。 A conventional eddy current flaw detection method will be explained with reference to the drawings.
第１図は、従来の渦流探傷法の基本構成図であ
る。 FIG. 1 is a basic configuration diagram of the conventional eddy current flaw detection method.
第１図において、１は、被検査材、２は、発振
器、３は、被検査材１に接近して配置した１対の
探傷コイルC1，C2を有する交流ブリツジ、４は、
交流ブリツジ３の出力を増巾、検波および信号処
理する回路を備えた電子回路、そして、５は記録
計を示す。 In FIG. 1, 1 is a material to be inspected, 2 is an oscillator, 3 is an AC bridge having a pair of flaw detection coils C 1 and C 2 arranged close to the material to be inspected 1, and 4 is:
An electronic circuit includes circuits for amplifying, detecting, and signal processing the output of the AC bridge 3, and 5 indicates a recorder.
１対の探傷コイルC1，C2を含む交流ブリツジ
３に、発振器２から交流電圧を印加すると、１対
の探傷コイルC1，C2による交流磁界が発生し、
磁束が被検査材１と交差する。これによつて被検
査材１には渦電流が発生する。今、１対の探傷コ
イルC1，C2を第１図中Ａ方向に移動させて、コ
イルC1，C2が疵６上に来たとすると、前記渦電
流の大きさが変化し、この反作用として１対の探
傷コイルC1，C2のインピーダンスが時系列的に
変化する。この結果、交流ブリツジ３が不平衡と
なり、疵６による疵信号が交流ブリツジ３の出力
端子から得られる。この信号は、電子回路４によ
つて、増巾、検波および信号処理され、この結果
が記録計５に記録され、疵６の検出が行える。 When an AC voltage is applied from the oscillator 2 to the AC bridge 3 including a pair of flaw detection coils C 1 and C 2 , an AC magnetic field is generated by the pair of flaw detection coils C 1 and C 2 .
The magnetic flux intersects the material 1 to be inspected. As a result, an eddy current is generated in the material 1 to be inspected. Now, if the pair of flaw detection coils C 1 and C 2 are moved in the direction A in Fig. 1 and the coils C 1 and C 2 come over the flaw 6, the magnitude of the eddy current changes and this As a reaction, the impedance of the pair of flaw detection coils C 1 and C 2 changes over time. As a result, the AC bridge 3 becomes unbalanced, and a flaw signal due to the flaw 6 is obtained from the output terminal of the AC bridge 3. This signal is amplified, detected, and processed by the electronic circuit 4, and the results are recorded in the recorder 5, so that the flaw 6 can be detected.
しかし、上述した従来の渦流探傷法は、次のよ
うな種々の問題を有する。 However, the conventional eddy current flaw detection method described above has the following various problems.
(1) 被検査材１が大面積のものである場合には、
１対の探傷コイルC1，C2を高速度で走査しな
ければならず、この走査は極めて困難である。(1) If the material to be inspected 1 has a large area,
The pair of flaw detection coils C 1 and C 2 must be scanned at high speed, and this scanning is extremely difficult.
(2) １対の探傷コイルC1，C2の形状および配置
方法によつては探傷できない疵がある。この問
題を解決する方法として回転プローブ型渦流法
がある。この方法は、１対の探傷コイルC1，
C2を高速度で円回転させることによつて、１
対の探傷コイルC1，C2により発生する磁界を
360゜に拡散して疵の方向性（横疵、縦疵）によ
る検出感度差を小さくする方法であるが、１対
の探傷コイルC1，C2を回転させる必要がある
ので、信号の伝達に回転トランスやスリツプリ
ングを使用する必要があり、耐久性に乏しくノ
イズ発生等の問題がある。(2) Depending on the shape and arrangement of the pair of flaw detection coils C 1 and C 2 , there may be flaws that cannot be detected. A rotating probe eddy current method is a method to solve this problem. This method uses a pair of flaw detection coils C 1 ,
By rotating C 2 in a circle at high speed, 1
The magnetic field generated by the pair of flaw detection coils C 1 and C 2 is
This method uses 360° diffusion to reduce the difference in detection sensitivity due to the directionality of flaws (horizontal flaws, vertical flaws), but since it is necessary to rotate the pair of flaw detection coils C 1 and C 2 , it is difficult to transmit signals. It is necessary to use a rotating transformer or a slip ring, which has problems such as poor durability and noise generation.
(3) 被検査材１の表面性状が悪いとＳ／Ｎ比が悪
く、所期の性能を得ることができず、しかも、
表層下に存在する疵の検出は行えない。(3) If the surface quality of the material to be inspected 1 is poor, the S/N ratio will be poor, making it impossible to obtain the desired performance, and furthermore,
It is not possible to detect flaws that exist below the surface layer.
この発明は、上述した(1)から(3)の問題点を解決
するためになされたものであつて、
円筒型をなす１次コイルと、前記１次コイルに
設けられた複数個の２次コイルとからなる探傷ヘ
ツドを、被検査材に接近させて配置し、前記１次
コイルに交流電圧を印加して交流磁界を形成し、
前記交流磁界によつて被検査材に生じた渦電流に
より前記２次コイルに誘起された信号を時系列的
に抽出し、前記抽出した信号を同期検波すること
によつて、被検査材に存在する欠陥を検出するこ
とに特徴を有する。 This invention was made to solve the problems (1) to (3) above, and includes a cylindrical primary coil and a plurality of secondary coils provided on the primary coil. A flaw detection head consisting of a coil is placed close to the material to be inspected, and an alternating current voltage is applied to the primary coil to form an alternating magnetic field;
By extracting in time series the signals induced in the secondary coil by eddy currents generated in the material to be inspected by the alternating magnetic field, and synchronously detecting the extracted signals, it is possible to detect the presence in the material to be inspected. It is characterized by detecting defects.
この発明の方法を図面を参照しながら説明す
る。 The method of this invention will be explained with reference to the drawings.
第２図は、この発明の方法の基本構成図であ
る。 FIG. 2 is a basic configuration diagram of the method of this invention.
第２図において、７は、発振器、８は、電力増
巾器、９は、移相器、１０は、マルチプレクサ、
１１は、信号増巾器、１２は、同期検波器、１３
は、分周器、１４は、サンプリングパルス発生
器、そして、１５は、第３図に示されるように、
円筒型をなす１個の１次コイル１６と、マルチプ
レクサ１０に各々接続され、１次コイル１６の内
周にそつて配置された複数個（ｎ個）の２次コイ
ル１７とから構成される探傷ヘツドを示す。探傷
ヘツド１５において、２次コイル１７は、筒状の
芯材にコイルを巻回したプローブ型コイルからな
り、円筒型の１次コイル１６の内側に、１次コイ
ル１６の周方向に沿つて軸線を１次コイル１６の
軸線と平行にしてそれぞれ配設されている。１次
コイル１６と２次コイル１７とは、１次コイル１
６の交流磁界によつて被検査材１に発生する渦電
流が、疵によつて変化することを２次コイル１７
によつて検知できる程度に接近している。１８
は、アナログ遅延回路、１９は、差動増巾器であ
る。アナログ遅延回路１８は、同期検波器１２に
より得られた出力電圧を、各２次コイル１７に誘
起される電圧のサンプリング周期Ｔだけ遅延させ
る作用をする。 In FIG. 2, 7 is an oscillator, 8 is a power amplifier, 9 is a phase shifter, 10 is a multiplexer,
11 is a signal amplifier, 12 is a synchronous detector, 13
is a frequency divider, 14 is a sampling pulse generator, and 15 is, as shown in FIG.
A flaw detection system consisting of one cylindrical primary coil 16 and a plurality of (n) secondary coils 17 each connected to a multiplexer 10 and arranged along the inner circumference of the primary coil 16. Shows the head. In the flaw detection head 15, the secondary coil 17 is a probe-type coil in which the coil is wound around a cylindrical core material, and the axis line is arranged inside the cylindrical primary coil 16 along the circumferential direction of the primary coil 16. are arranged parallel to the axis of the primary coil 16, respectively. The primary coil 16 and the secondary coil 17 are the primary coil 1
The secondary coil 17 shows that the eddy current generated in the inspected material 1 by the alternating current magnetic field 6 changes due to flaws.
close enough to be detected by 18
is an analog delay circuit, and 19 is a differential amplifier. The analog delay circuit 18 functions to delay the output voltage obtained by the synchronous detector 12 by the sampling period T of the voltage induced in each secondary coil 17.
被検査材１に接近させて配置した探傷ヘツド１
５の１次コイル１６に、発振器７から固定発振周
波数の交流電圧を電力増巾器８を介して印加する
と、１次コイル１６による交流磁界が発生し、磁
束が被検査材１と交差する。これによつて、被検
査材１に渦電流が発生し、被検査材１に疵が存在
すると前記渦電流の値が変化する。渦電流の値に
対応して反磁界が発生し、このため疵に近接して
いる２次コイル１７には、疵に対応した電圧が誘
起される。発振器７からの出力電圧の周波数は、
分周器１３によつて所定の周波数に分周され、こ
の分周された周波数の出力電圧に基き、サンプリ
ングパルス発生器１４によつて、サンプリングパ
ルスが作られ、このサンプリングパルスに基き、
マルチプレクサ１０に入力された２次コイル１７
の出力電圧が時系列的にマルチプレクサ１０から
出力される。（第４図参照）。マルチプレクサ１０
からの出力電圧は、信号増巾器１１によつて所定
の大きさに増巾された後、同期検波器１２に印加
されて直流電圧に変換される。同期検波器１２か
らの出力電圧がアナログ遅延回路１８と差動増巾
器１９とに加えられ、疵がない場合には、差動増
巾器１９に加えられる前記２つの電圧は等しいの
で、差動増巾器１９から電圧は出力されない。こ
れに対して、疵が存在する場合、差動増巾器１９
には、同期検波器１２からの、疵による誘起電圧
に対応した電圧と、アナログ遅延回路１８から
の、１周期前の疵が存在しない場合の電圧とが加
えられるので、結局、差動増巾器１９からは、疵
による電圧のみが出力される。従つて、被検査材
の表面性状にかかわらず、確実に疵の検出を行う
ことができる。 Flaw detection head 1 placed close to inspected material 1
When an alternating current voltage with a fixed oscillation frequency is applied from the oscillator 7 to the primary coil 16 of No. 5 via the power amplifier 8, an alternating magnetic field is generated by the primary coil 16, and the magnetic flux intersects with the material to be inspected 1. As a result, an eddy current is generated in the material 1 to be inspected, and if a flaw exists in the material 1 to be inspected, the value of the eddy current changes. A demagnetizing field is generated corresponding to the value of the eddy current, and therefore a voltage corresponding to the flaw is induced in the secondary coil 17 that is close to the flaw. The frequency of the output voltage from the oscillator 7 is
The frequency is divided into a predetermined frequency by the frequency divider 13, and based on the output voltage of this divided frequency, a sampling pulse is generated by the sampling pulse generator 14, and based on this sampling pulse,
Secondary coil 17 input to multiplexer 10
The output voltages are output from the multiplexer 10 in time series. (See Figure 4). multiplexer 10
The output voltage is amplified to a predetermined magnitude by a signal amplifier 11, and then applied to a synchronous detector 12 and converted into a DC voltage. The output voltage from the synchronous detector 12 is applied to the analog delay circuit 18 and the differential amplifier 19, and if there is no flaw, the two voltages applied to the differential amplifier 19 are equal, so the difference is No voltage is output from the dynamic amplifier 19. On the other hand, if a flaw exists, the differential amplifier 19
Since the voltage corresponding to the induced voltage due to the flaw from the synchronous detector 12 and the voltage from the analog delay circuit 18 when the flaw does not exist one cycle before are added to , the differential amplification Only the voltage due to the flaw is output from the device 19. Therefore, flaws can be reliably detected regardless of the surface properties of the inspected material.
以上の説明から明らかなように、この発明の探
傷法によれば、探傷ヘツドの複数個の２次コイル
に誘起される電圧をサンプリングパルスによつて
時系列的にマルチプレクサから出力させる場合、
各２次コイルに誘起される電圧のサンプリング周
期をＴとすると、プローブコイル型渦流探傷法に
おいて、周期Ｔでプローブコイルを回転させた場
合と同じ探傷面積を得ることができる。また、探
傷ヘツドの１次コイルを円筒型としたので、被検
査材に生じる渦電流も円電流となり、このため、
疵の方向（横疵、縦疵）に無関係に同じ検出感度
を得ることができる。しかも、上述したように、
被検査材の表面性状が悪くても、即ち、被検査材
の表面にゆがみ等が生じていても、確実に疵の検
出が行なえる。 As is clear from the above description, according to the flaw detection method of the present invention, when the voltages induced in the plurality of secondary coils of the flaw detection head are output from the multiplexer in time series using sampling pulses,
If the sampling period of the voltage induced in each secondary coil is T, then in the probe coil type eddy current flaw detection method, it is possible to obtain the same flaw detection area as when the probe coil is rotated at the period T. In addition, since the primary coil of the flaw detection head is cylindrical, the eddy current generated in the material to be inspected becomes a circular current.
The same detection sensitivity can be obtained regardless of the direction of the flaw (horizontal flaw, vertical flaw). Moreover, as mentioned above,
Even if the surface quality of the material to be inspected is poor, that is, even if the surface of the material to be inspected is distorted, flaws can be reliably detected.
この発明の更に別の実施例について第５図を参
照しながら説明する。 Still another embodiment of the invention will be described with reference to FIG.
被検査材中に発生する渦電流の浸透深さは、被
検査材の電気的特性、磁気的特性および探傷周波
数によつて決定され、探傷周波数、すなわち、１
次コイルに流す電流の周波数を低くするほど浸透
深さが深くなる。 The penetration depth of the eddy current generated in the material to be inspected is determined by the electrical and magnetic properties of the material to be inspected and the flaw detection frequency.
The lower the frequency of the current flowing through the next coil, the deeper the penetration depth.
この実施例は、上述した特性を応用して、探傷
ヘツド中の１次コイルに周波数の異る２種類の交
流電流を供給し、被検査材の表層下に存在する欠
陥を探傷する方法である。 This example applies the above-mentioned characteristics to supply two types of alternating currents with different frequencies to the primary coil in the flaw detection head, and detects defects existing under the surface layer of the material to be inspected. .
第５図において、８，１０，１１，１３，１
４，１５は、第２図に示したものと同様のもので
ある。２０は、高周波発振器、２１は、低周波発
振器、２２は、発振器２０と２１からの交流電圧
を加算するための加算器、２３は、高周波用バン
ドパスフイルタ、２４は、低周波用バンドパスフ
イルタ、２５は、高周波用同期検波器、２６は、
低周波用同期検波器、２７は、高周波用移相器、
２８は、低周波用移相器、そして、２９は、高周
波用同期検波器２５と低周波用同期検波器２６か
らの出力電圧の差分をとる差動増巾器である。 In Figure 5, 8, 10, 11, 13, 1
4 and 15 are similar to those shown in FIG. 20 is a high frequency oscillator, 21 is a low frequency oscillator, 22 is an adder for adding the AC voltages from the oscillators 20 and 21, 23 is a high frequency band pass filter, and 24 is a low frequency band pass filter. , 25 is a high frequency synchronous detector, 26 is
27 is a synchronous detector for low frequencies; 27 is a phase shifter for high frequencies;
28 is a phase shifter for low frequencies, and 29 is a differential amplifier that takes the difference between the output voltages from the synchronous detector 25 for high frequencies and the synchronous detector 26 for low frequencies.
１対の高周波および低周波発振器２０および２
１からの交流電圧は加算器２２によつて加算さ
れ、電力増巾器８によつて所定の大きさに増巾さ
れた後、探傷ヘツド１５の１次コイル１６に加え
られる。これにより、１次コイル１６からは高周
波と低周波の交流磁界が生じ、被検査材には高周
波と低周波の渦電流が発生する。この渦電流によ
つて２次コイル１７に誘起された高周波と低周波
成分を有する電圧は、前述した場合と同様にマル
チプレクサ１０によつて時系列的に抽出された
後、信号増巾器１１で所定の大きさに増巾され
る。この増巾された信号は、１対の高周波用およ
び低周波用バンドパスフイルタ２３および２４に
よつて、高周波および低周波の２種類の周波数の
信号に弁別される。この後、これらの信号は、１
対の高周波用および低周波用同期検波器２７およ
び２８によつて夫々直流電圧に変換される。これ
らの直流電圧は、夫々差動増巾器２９に加えら
れ、両者の差分がとられる。この差分が被検査材
の表面下に存在する欠陥を示す信号となり、内部
欠陥の検出が行える。 A pair of high frequency and low frequency oscillators 20 and 2
The AC voltages from the flaw detection head 15 are added by an adder 22, amplified to a predetermined magnitude by a power amplifier 8, and then applied to the primary coil 16 of the flaw detection head 15. As a result, high-frequency and low-frequency alternating magnetic fields are generated from the primary coil 16, and high-frequency and low-frequency eddy currents are generated in the material to be inspected. The voltage having high frequency and low frequency components induced in the secondary coil 17 by this eddy current is extracted in time series by the multiplexer 10 as in the case described above, and then is extracted by the signal amplifier 11. The width is increased to a predetermined size. This amplified signal is discriminated into two types of frequency signals, high frequency and low frequency, by a pair of high frequency and low frequency band pass filters 23 and 24. After this, these signals become 1
The signals are converted into DC voltages by a pair of high-frequency and low-frequency synchronous detectors 27 and 28, respectively. These DC voltages are respectively applied to a differential amplifier 29, and the difference between the two is calculated. This difference becomes a signal indicating defects existing under the surface of the material to be inspected, and internal defects can be detected.
以上説明したように、この発明によれば、大面
積の被検査材の表面および内部に存在する欠陥
を、欠陥の方向に無関係に高感度で検出すること
ができ、しかも、探傷コイルを機械的に円回転さ
せる必要もないので、故障の発生もきわめて少な
い等種々の有用な効果がもたらされる。 As explained above, according to the present invention, defects existing on the surface and inside of a large area of a material to be inspected can be detected with high sensitivity regardless of the direction of the defect. Since there is no need for continuous circular rotation, various useful effects such as extremely low occurrence of failures are brought about.
第１図は、従来の渦流探傷法の基本構成図、第
２図は、この発明の実施例の基本構成図、第３図
は、この発明に使用される探傷ヘツドの説明図、
第４図は、マルチプレクサからの各２次コイルの
出力信号を示す図、第５図は、この発明の他の実
施例の基本構成図である。図面において、
１……被検査材、２……発振器、３……交流ブ
リツジ、４……電子回路、５……記録計、６……
疵、７……発振器、８……電力増巾器、９……移
相器、１０……マルチプレクサ、１１……信号増
巾器、１２……同期検波器、１３……分周器、１
４……サンプリングパルス発生器、１５……探傷
ヘツド、１６……１次コイル、１７……２次コイ
ル、１８……アナログ遅延回路、１９……差動増
巾器、２０……高周波発振器、２１……低周波発
振器、２２……加算器、２３……高周波用バンド
パスフイルタ、２４……低周波用バンドパスフイ
ルタ、２５……高周波用同期検波器、２６……低
周波用同期検波器、２７……高周波用移相器、２
８……低周波用移相器、２９……差動増巾器。
FIG. 1 is a basic configuration diagram of a conventional eddy current flaw detection method, FIG. 2 is a basic configuration diagram of an embodiment of this invention, and FIG. 3 is an explanatory diagram of a flaw detection head used in this invention.
FIG. 4 is a diagram showing the output signal of each secondary coil from the multiplexer, and FIG. 5 is a basic configuration diagram of another embodiment of the present invention. In the drawings, 1... Material to be inspected, 2... Oscillator, 3... AC bridge, 4... Electronic circuit, 5... Recorder, 6...
Defect, 7... Oscillator, 8... Power amplifier, 9... Phase shifter, 10... Multiplexer, 11... Signal amplifier, 12... Synchronous detector, 13... Frequency divider, 1
4... Sampling pulse generator, 15... Flaw detection head, 16... Primary coil, 17... Secondary coil, 18... Analog delay circuit, 19... Differential amplifier, 20... High frequency oscillator, 21...Low frequency oscillator, 22...Adder, 23...High frequency band pass filter, 24...Low frequency band pass filter, 25...High frequency synchronous detector, 26...Low frequency synchronous detector , 27...High frequency phase shifter, 2
8...Low frequency phase shifter, 29...Differential amplifier.
Claims (1)
の近傍に前記１次コイル沿つて配設された、軸線
が前記１次コイルの軸線と平行な複数個のプロー
ブ型２次コイルとからなる探傷ヘツドを、被検査
材に接近させて配置し、前記１次コイルに交流電
圧を印加して交流磁界を形成し、前記交流磁界に
よつて被検査材に生じた渦電流により前記２次コ
イルに誘起された信号を時系列的に抽出し、前記
抽出した信号を同期検波し、前記検波した信号を
一定時間遅延させ、前記遅延させた信号と、前記
検波した信号との差分を取ることによつて、被検
査材表面に存在する欠陥を検出することを特徴と
する渦流探傷法。 ２ 円筒型をなす１次コイルと、前記１次コイル
の近傍に前記１次コイルに沿つて配設された、軸
線が前記１次コイルの軸線と平行な複数個のプロ
ーブ型２次コイルとからなる探傷ヘツドを、被検
査材に接近させて配置し、前記１次コイルに高周
波の交流電圧と低周波の交流電圧とを印加して高
周波と低周波の交流磁界を形成し、前記交流磁界
によつて被検査材に生じた高周波と低周波の渦電
流により前記２次コイルに誘起された高周波と低
周波の成分を有する信号を時系列的に抽出し、前
記抽出した信号を高周波と低周波との信号に弁別
し、これらの信号を同期検波し、同期検波した高
周波成分を有する電圧と低周波成分を有する電圧
との差分をとることによつて、被検査材内部に存
在する欠陥を検出することを特徴とする渦流探傷
法。[Scope of Claims] 1. A cylindrical primary coil, and a plurality of probe types disposed near the primary coil along the primary coil, the axis of which is parallel to the axis of the primary coil. A flaw detection head consisting of a secondary coil is placed close to the material to be inspected, an alternating voltage is applied to the primary coil to form an alternating magnetic field, and the vortices generated in the material to be inspected by the alternating magnetic field are A signal induced in the secondary coil by a current is extracted in time series, the extracted signal is synchronously detected, the detected signal is delayed for a certain period of time, and the delayed signal and the detected signal are combined. An eddy current flaw detection method that detects defects on the surface of the material being inspected by taking the difference between the 2. A cylindrical primary coil, and a plurality of probe-type secondary coils arranged near the primary coil along the primary coil, the axis of which is parallel to the axis of the primary coil. A flaw detection head is placed close to the material to be inspected, and a high frequency alternating current voltage and a low frequency alternating current voltage are applied to the primary coil to form high frequency and low frequency alternating magnetic fields. Therefore, a signal having high-frequency and low-frequency components induced in the secondary coil by high-frequency and low-frequency eddy currents generated in the material to be inspected is extracted in time series, and the extracted signal is divided into high-frequency and low-frequency components. Detects defects inside the material to be inspected by discriminating these signals into signals, synchronously detecting these signals, and taking the difference between the synchronously detected voltage with high frequency components and the voltage with low frequency components. Eddy current flaw detection method is characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56118540A JPS5821159A (en) | 1981-07-30 | 1981-07-30 | Eddy current flaw detecting method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56118540A JPS5821159A (en) | 1981-07-30 | 1981-07-30 | Eddy current flaw detecting method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5821159A JPS5821159A (en) | 1983-02-07 |
| JPH0125019B2 true JPH0125019B2 (en) | 1989-05-16 |
Family
ID=14739117
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56118540A Granted JPS5821159A (en) | 1981-07-30 | 1981-07-30 | Eddy current flaw detecting method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5821159A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003149212A (en) * | 2001-11-09 | 2003-05-21 | Japan Science & Technology Corp | Nondestructive inspecting apparatus |
| JP2010048723A (en) * | 2008-08-22 | 2010-03-04 | Kobe Steel Ltd | Reinforcing bar corrosion inspection method and reinforcing bar corrosion inspection apparatus |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20030092970A (en) * | 2002-05-31 | 2003-12-06 | 박관수 | Apparatus detecting a foreign substance by magnetic non-contact sensor and method thereof |
| JP5727894B2 (en) * | 2011-08-23 | 2015-06-03 | マークテック株式会社 | Eddy current flaw detection method |
| JP6601599B1 (en) * | 2017-12-15 | 2019-11-06 | 日本精工株式会社 | Rolling part inspection method and rolling part inspection apparatus |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56163451A (en) * | 1980-05-21 | 1981-12-16 | Hitachi Ltd | Probing coil for detecting crack by utilizing eddy current |
-
1981
- 1981-07-30 JP JP56118540A patent/JPS5821159A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56163451A (en) * | 1980-05-21 | 1981-12-16 | Hitachi Ltd | Probing coil for detecting crack by utilizing eddy current |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003149212A (en) * | 2001-11-09 | 2003-05-21 | Japan Science & Technology Corp | Nondestructive inspecting apparatus |
| JP2010048723A (en) * | 2008-08-22 | 2010-03-04 | Kobe Steel Ltd | Reinforcing bar corrosion inspection method and reinforcing bar corrosion inspection apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5821159A (en) | 1983-02-07 |
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