JP3307220B2 - Method and apparatus for flaw detection of magnetic metal body - Google Patents
Method and apparatus for flaw detection of magnetic metal bodyInfo
- Publication number
- JP3307220B2 JP3307220B2 JP08350696A JP8350696A JP3307220B2 JP 3307220 B2 JP3307220 B2 JP 3307220B2 JP 08350696 A JP08350696 A JP 08350696A JP 8350696 A JP8350696 A JP 8350696A JP 3307220 B2 JP3307220 B2 JP 3307220B2
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- JP
- Japan
- Prior art keywords
- signal
- eddy current
- detection signal
- flaw detection
- metal body
- 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.)
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- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、磁性金属の内面あ
るいは表面に存在する介在物等の微小な欠陥を検出する
方法および装置、特に、漏洩磁束探傷法と渦流探傷法を
併用した磁性金属体の探傷方法および装置に関するもの
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting minute defects such as inclusions present on the inner surface or surface of a magnetic metal, and more particularly, to a magnetic metal body using both a leakage magnetic flux inspection method and an eddy current inspection method. Flaw detection method and apparatus.
【０００２】[0002]
【従来の技術】金属材料などでは、内部、表面に欠陥が
あると強度などその品質に問題が生じる可能性があるた
め、品質管理上あるいは品質保証上、Ｘ線透過法、超音
波探傷法など様々な非破壊的な検査が行われている。た
とえば、鋼管溶接部の割れなどの検出には、Ｘ線透過
法、超音波探傷法が用いられている。一方、表面近傍の
欠陥の検出や薄い帯状材料の表面及び内部欠陥の検出に
関しては、特にオンラインでは、電磁気的な方法、すな
わち漏洩磁束探傷法や渦流探傷法がよく用いられる。2. Description of the Related Art In a metal material, if there is a defect in the inside or the surface, a problem such as strength may occur. Therefore, in quality control or quality assurance, an X-ray transmission method, an ultrasonic inspection method, and the like. Various non-destructive tests have been performed. For example, an X-ray transmission method and an ultrasonic flaw detection method are used to detect a crack in a welded portion of a steel pipe. On the other hand, regarding the detection of a defect near the surface and the detection of a surface and an internal defect of a thin band-shaped material, an electromagnetic method, that is, a magnetic flux leakage inspection method or an eddy current inspection method is often used particularly online.
【０００３】製缶材料用の極薄鋼板では、介在物などの
欠陥があると、製缶時にフランジクラックが発生するな
どの問題が生じる可能性がある。このような欠陥を検出
する方法として、漏洩磁束法などを用いたオンライン高
速欠陥検出器が開発されてきた。たとえば、特開平３ー
１７５３５２号公報には、図４に示すように、鋼板２１
を挟んで、一方の側に鋼板を磁化するための磁化器２２
を、他方の側に欠陥により生じる漏洩磁束を検出する磁
気センサアレイ２３を幅方向に配し、それぞれを非磁性
ロール２４、２５の中に入れて探傷する方法が提案され
ている。このような方法によれば、センサ２３と被検査
体である鋼板２１の距離を小さく安定に保つことがで
き、鋼板２１中の微小な欠陥が、感度良く高速に検出で
きる。[0003] In ultra-thin steel plates for can-making materials, if there are defects such as inclusions, problems such as generation of flange cracks during can-making may occur. As a method of detecting such a defect, an on-line high-speed defect detector using a leakage magnetic flux method or the like has been developed. For example, Japanese Patent Application Laid-Open No. 3-175352 discloses a steel plate 21 as shown in FIG.
Magnetizer 22 for magnetizing a steel plate on one side
On the other side, a magnetic sensor array 23 for detecting a leakage magnetic flux caused by a defect is arranged in the width direction, and each of the magnetic sensor arrays 23 is inserted into non-magnetic rolls 24 and 25 to perform flaw detection. According to such a method, the distance between the sensor 23 and the steel plate 21 to be inspected can be kept small and stable, and minute defects in the steel plate 21 can be detected at high speed with high sensitivity.
【０００４】また、特開平５ー１６４７４５号公報に
は、鋼板などの表面に存在する孔食などを差分型プロー
ブを用いた渦流法により探傷する方法が提案されてい
る。これは、図５に示すようなＥ型のコアを用い、真中
の磁極３２ｂに巻いたコイル３２ｅを励磁用に、両端の
磁極３２ａ，３２ｃに巻いたコイル３２ｄ，３２ｆを検
出用に使用し、コイル３２ｄと３２ｆの出力の差分信号
を処理することにより欠陥を検出するものである。差分
信号を処理することにより欠陥による渦流信号の微小な
変化を感度良く検出することができるので、欠陥が小さ
い場合、板が厚い場合等においても、欠陥を精度良く検
出することができる。Japanese Patent Application Laid-Open No. Hei 5-164745 proposes a method of detecting pits and the like existing on the surface of a steel plate or the like by an eddy current method using a differential probe. This involves using an E-shaped core as shown in FIG. 5, using a coil 32e wound around a middle magnetic pole 32b for excitation, and coils 32d and 32f wound around magnetic poles 32a and 32c at both ends for detection. A defect is detected by processing a difference signal between the outputs of the coils 32d and 32f. By processing the difference signal, a minute change in the eddy current signal due to the defect can be detected with high sensitivity, so that the defect can be detected with high accuracy even when the defect is small or the plate is thick.
【０００５】また、特開平５ー１６４７４５号公報に
は、一つのセンサで渦流信号に加え漏洩磁束信号を検出
する方法についても述べられている。それは、検出コイ
ルによって得られた信号から、適当なローパスフィルタ
を用いることで漏洩磁束信号を得るというものである。
その方法を使うと、渦流探傷法、あるいは漏洩磁束探傷
法のうち少なくともどちらかで一方で欠陥が検出できる
場合には、その検出できる方の信号から欠陥の有無など
を判断すればよいので、渦流探傷法、漏洩磁束探傷法の
どちらか一方だけで検出する場合よりも検出能は高くな
ることが期待できる。Japanese Patent Laid-Open Publication No. Hei 5-164745 also discloses a method for detecting a leakage magnetic flux signal in addition to an eddy current signal with one sensor. That is, a leakage magnetic flux signal is obtained from a signal obtained by a detection coil by using an appropriate low-pass filter.
If a defect can be detected by at least one of the eddy current flaw detection method and the leakage magnetic flux flaw detection method, it is sufficient to judge the presence or absence of a defect from the signal of the detectable one. It can be expected that the detectability will be higher than in the case where only one of the flaw detection method and the leakage magnetic flux detection method is used for detection.
【０００６】更に、渦流探傷法と漏洩磁束探傷法の両者
を使って検出能を上げるという方法としては、鋼管、ス
ラブなどの磁性体表面の欠陥を検出する方法として、特
開昭６３ー２３５８５４号公報に、複合磁場を用いた方
法が提案されている。これは、漏洩磁束探傷法は割れ状
欠陥に強く、また渦流探傷法はピット状欠陥に強いこと
を利用して、この２つの方法により同時に探傷できるよ
うに計測器を工夫することで、２つのタイプの欠陥を検
出できるようにしたものである。[0006] Further, as a method of improving the detection performance by using both the eddy current flaw detection method and the leakage magnetic flux flaw detection method, a method of detecting a defect on the surface of a magnetic material such as a steel pipe or a slab is disclosed in JP-A-63-235854. In the gazette, a method using a composite magnetic field is proposed. This is based on the fact that the magnetic flux leakage inspection method is resistant to crack-like defects and the eddy current inspection method is resistant to pit-like defects. It is intended to be able to detect type defects.
【０００７】即ち、図６に示されるように、隣接するコ
イル４１とコイル４２が同方向に励磁され、隣接するコ
イル４２とコイル４３は逆方向に励磁される。そして、
コイル４１とコイル４２からなる第１のコイル対により
被検査対象４６の表面に平行な磁場４７ａが発生し、欠
陥により発生する磁場４７ａの漏洩磁束信号が磁気セン
サ４４により検出される。一方、コイル４２とコイル４
３からなる第２のコイル対より被検査対象４６の表面に
垂直な磁場４７ｂが発生し、この磁場４７ｂにより発生
する渦電流が欠陥により妨げられることに起因する磁束
の変化が磁気センサ４５により検出されるのである。こ
れも、特開平５ー１６４７４５号公報に記載されている
方法同様、少なくともどちらか一つで欠陥が検出できる
場合には、その検出できる方法の信号から欠陥の有無を
判断すればよいので、どれか一つだけの方法で検出する
場合よりも検出能は高くなることが期待できる。That is, as shown in FIG. 6, adjacent coils 41 and 42 are excited in the same direction, and adjacent coils 42 and 43 are excited in opposite directions. And
A magnetic field 47 a parallel to the surface of the inspection object 46 is generated by the first coil pair including the coil 41 and the coil 42, and a leakage magnetic flux signal of the magnetic field 47 a generated by the defect is detected by the magnetic sensor 44. On the other hand, coil 42 and coil 4
A magnetic field 47b perpendicular to the surface of the inspection object 46 is generated from the second coil pair composed of the magnetic field 47, and a change in magnetic flux due to the eddy current generated by the magnetic field 47b being hindered by a defect is detected by the magnetic sensor 45. It is done. Similarly to the method described in Japanese Patent Application Laid-Open No. 5-164745, when a defect can be detected by at least one of the methods, the presence or absence of a defect can be determined from a signal of the detectable method. It can be expected that the detection ability will be higher than in the case of detecting by only one method.
【０００８】[0008]
【発明が解決しようとする課題】前記いずれの方法にお
いても、検出すべき欠陥が小さい場合や厚い金属帯の内
部欠陥を検出する場合には、欠陥信号が弱くなり、相対
的にＳ／Ｎ比が劣化して欠陥が検出しにくくなる。ノイ
ズとしては特に、被検査体に起因する地合ノイズが問題
になることが多い。地合ノイズは漏洩磁束探傷法や渦流
探傷法それぞれの測定条件を最適化することで小さくす
ることはできるが、信号が小さくなってくるにつれて地
合ノイズと信号は区別しにくくなり、欠陥の検出が困難
になってくる。また、漏洩磁束探傷法と渦流探傷法を併
用し、それぞれの検出しやすい欠陥を検出することでシ
ステム全体として検出能を上げる方法でも、両方の探傷
法において共にＳ／Ｎ比が悪くなるため十分な検出能が
得られない。In any of the above methods, when the defect to be detected is small or when an internal defect in a thick metal band is detected, the defect signal becomes weak and the S / N ratio becomes relatively small. Deteriorates, making it difficult to detect defects. In particular, formation noise caused by the test object often becomes a problem. The formation noise can be reduced by optimizing the measurement conditions for each of the leakage magnetic flux inspection method and the eddy current inspection method.However, as the signal becomes smaller, it becomes more difficult to distinguish between the formation noise and the signal. Becomes difficult. In addition, even if the leakage flux inspection method and the eddy current inspection method are used in combination to increase the detectability of the entire system by detecting each easily detectable defect, the S / N ratio is deteriorated in both the inspection methods, so that it is sufficient. High detectability cannot be obtained.
【０００９】本発明はこのような問題点を解決するため
になされたもので、渦流探傷法単独や漏洩磁束探傷法単
独、あるいは、それらの単なる併用だけでは十分に検出
できなかった微小欠陥の検出ができるようにすることを
目的とする。SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is intended to detect a small defect which cannot be sufficiently detected by the eddy current flaw detection method alone, the leakage magnetic flux flaw detection method alone, or a combination thereof. The purpose is to be able to.
【００１０】[0010]
【課題を解決するための手段】前記課題は、(1) 被検査
磁性金属体の検査部を磁化すると共に検査部に渦電流を
発生させる工程、(2) 磁性金属体の欠陥から発生する漏
洩磁束を磁気センサにより検出して漏洩磁束探傷信号を
得る工程、(3) 渦電流が磁性金属体の欠陥により乱れる
ことにより生ずる磁場を磁気センサで検出して渦流検出
信号を得て、これを位相検波して渦流探傷信号を得る工
程、(4) 少なくとも一つの測定条件における漏洩磁束探
傷信号と少なくとも一つの測定条件における渦流探傷信
号の、実質的に同一の検査部位から得られた信号波形同
士に対し、当該複数の信号波形中に共通して存在する欠
陥信号をノイズ信号に対して相対的に強調するような演
算を含む信号処理を行って得られる複合探傷信号を用い
て磁性金属体の欠陥を検出する工程、を備えたことを特
徴とする磁性金属体の探傷方法により解決される。The object of the present invention is to provide: (1) a step of magnetizing an inspection part of a magnetic metal body to be inspected and generating an eddy current in the inspection part; (2) a leakage caused by a defect of the magnetic metal body. (3) a magnetic sensor that detects the magnetic flux generated by the eddy current being disturbed by a defect in the magnetic metal body to obtain a eddy current detection signal, and obtains an eddy current detection signal. A step of detecting and obtaining an eddy current flaw detection signal, (4) a signal waveform obtained from substantially the same inspection site between the leakage magnetic flux flaw detection signal under at least one measurement condition and the eddy current flaw detection signal under at least one measurement condition; On the other hand, a defect of the magnetic metal body is obtained by using a composite flaw detection signal obtained by performing a signal processing including an operation of emphasizing a defect signal commonly present in the plurality of signal waveforms relatively to a noise signal. Detect And a step of ejecting the magnetic metal member.
【００１１】また、この方法は、(1) 被検査磁性金属体
を磁化する磁化装置、(2) Ｅ型形状の強磁性体で作られ
Ｅ型を成す３個の磁極の列が磁性金属体との相対的運動
方向に沿うように配置されたＥ型コア、およびＥ型コア
の３個の磁極にそれぞれ巻いた３個のコイルとを有して
なるＥ型磁気センサ、(3) 前記Ｅ型コアの３個のコイル
の内の両端のコイルに交流の励磁信号を印加するための
少なくとも一つの励磁信号発生装置、(4) 前記Ｅ型コア
の中央のコイルから検出信号を取り出し、この検出信号
から励磁信号と同じ周波数成分を除去して漏洩磁束探傷
信号を得るための漏洩磁束探傷信号用フィルタ、(5) 前
記Ｅ型コアの中央のコイルからの検出信号を位相検波し
て渦流探傷信号を得るための少なくとも一つの位相検波
器、(6) 実質的に同一の検査部位から得られた前記漏洩
磁束探傷信号と前記渦流探傷信号の波形中に共通して存
在する欠陥信号をノイズ信号に対して相対的に強調する
ような演算を含む信号処理を行って総合探傷信号を得る
ための総合探傷信号演算器、(7) 総合探傷信号演算器の
出力に基づいて磁性金属体の欠陥の有無または欠陥の等
級を判断するための判定回路、とを有してなる磁性金属
体探傷装置により実施することができる。In addition, this method includes: (1) a magnetizing device for magnetizing a magnetic metal body to be inspected; and (2) a row of three E-shaped magnetic poles made of an E-shaped ferromagnetic material. (3) an E-type magnetic sensor comprising: an E-type core arranged along the direction of relative movement with the E-type core; and three coils respectively wound around three magnetic poles of the E-type core. At least one excitation signal generator for applying an AC excitation signal to the coils at both ends of the three coils of the mold core; (4) detecting a detection signal from the center coil of the E-shaped core, A filter for detecting a magnetic flux leakage signal by removing the same frequency component as the excitation signal from the signal, and (5) an eddy current detection signal by phase-detecting a detection signal from a center coil of the E-shaped core. At least one phase detector to obtain (6) substantially identical A signal processing including an operation of emphasizing a defect signal commonly present in the waveforms of the leakage magnetic flux detection signal and the eddy current detection signal obtained from a portion relative to a noise signal is performed to perform a comprehensive flaw detection signal. And a determination circuit for determining the presence or absence of a defect in the magnetic metal body based on the output of the comprehensive flaw detection signal arithmetic unit, and (7) a magnetic circuit comprising: It can be performed by a body flaw detector.
【００１２】複数の信号波形中に共通して存在する欠陥
信号をノイズ信号に対して相対的に強調するような演算
を行って得られる複合探傷信号を用いて磁性金属体の欠
陥を検出するので、Ｓ／Ｎ比が改善され、微小な欠陥を
感度良く検出することができる。Since a defect of a magnetic metal body is detected by using a composite flaw detection signal obtained by performing an operation for emphasizing a defect signal commonly present in a plurality of signal waveforms relative to a noise signal. , S / N ratio is improved, and a minute defect can be detected with high sensitivity.
【００１３】[0013]
【発明の実施の形態】渦流検出信号としては、位相検波
における位相、励磁信号の周波数、探傷面（被検査磁性
金属帯の表裏面）の３つの測定条件のうち少なくとも１
条件が異なる複数の渦流探傷信号を組み合わせて用いる
ことができる。測定条件の異なる信号を使用して、その
出力を演算することにより、信号成分をノイズ成分に対
して相対的に強調することが可能になる。BEST MODE FOR CARRYING OUT THE INVENTION As an eddy current detection signal, at least one of three measurement conditions of a phase in phase detection, a frequency of an excitation signal, and a flaw detection surface (front and back surfaces of a magnetic metal band to be inspected) is used.
A plurality of eddy current flaw detection signals having different conditions can be used in combination. By calculating the output using signals having different measurement conditions, it becomes possible to emphasize the signal component relatively to the noise component.
【００１４】演算が行われる漏洩磁束探傷信号の周波数
帯域と渦流探傷信号の周波数帯域をほぼ一致させるよう
にすれば、両信号の欠陥部での形が似たものとなり、欠
陥信号が強調されやすく、Ｓ／Ｎ比を改善しやすくな
る。If the frequency band of the leakage magnetic flux detection signal on which the calculation is performed and the frequency band of the eddy current detection signal are substantially matched, the shapes of the defect portions of the two signals are similar, and the defect signal is easily emphasized. , And the S / N ratio can be easily improved.
【００１５】一つの磁気センサで漏洩磁束探傷信号と渦
流検出信号の一組を得るようにすれば、構成が簡単にな
ると共に、同一の部位から漏洩磁束探傷信号と渦流検出
信号を同時に得ることができ、信号処理が簡単になる。If one set of the magnetic flux sensor is used to obtain a set of the leakage magnetic flux detection signal and the eddy current detection signal, the configuration is simplified, and the leakage magnetic flux detection signal and the eddy current detection signal can be simultaneously obtained from the same portion. And signal processing is simplified.
【００１６】本発明で「実質的に同一の場所」というの
は、２次元的（被検査磁性金属板の平面）な意味で同一
の場所をいい、漏洩磁束探傷を金属体のある面から行
い、渦流探傷をそれと反対の面から行う場合をも含むも
のである。このような探傷方法を採用することにより、
表面性状等に起因するノイズが表裏面で相殺されるの
で、Ｓ／Ｎ比を向上させることができる。In the present invention, "substantially the same place" means the same place in a two-dimensional sense (the plane of the magnetic metal plate to be inspected). This includes the case where eddy current testing is performed from the opposite surface. By adopting such a flaw detection method,
Since noise caused by surface properties and the like is offset on the front and back surfaces, the S / N ratio can be improved.
【００１７】「複数の信号波形中に共通して存在する欠
陥信号をノイズ信号に対して相対的に強調するような演
算」として、少なくとも一つの漏洩磁束探傷信号Ｍ(x)
と少なくとも一つの渦流探傷信号Ｅ(x) （ｘは被検査磁
性金属板上の位置）との間で Ａ(x) ＝Ｍ(x) ＊Ｅ(x) ……（１） なる演算を行わせる。ここで、＊は、例えば乗算、自乗
和、Ｍ(x) とＥ(x) それぞれの絶対値の和、Ｍ(x) とＥ
(x) それぞれの絶対値の小さい方の値等を示す演算子で
ある。At least one leakage magnetic flux detection signal M (x) is used as “an operation for emphasizing a defect signal commonly present in a plurality of signal waveforms relatively to a noise signal”.
A (x) = M (x) * E (x) (1) is performed between the signal and at least one eddy current detection signal E (x) (x is a position on the magnetic metal plate to be inspected). Let Here, * represents, for example, multiplication, sum of squares, sum of absolute values of M (x) and E (x), and M (x) and E (x).
(x) This operator indicates the smaller value of each absolute value.
【００１８】欠陥による信号の変化は、渦流探傷法と漏
洩磁束探傷法で同じ位置にでることが期待されるが、ノ
イズについては両者が異なる現象を利用していること、
厚み方向のノイズ源の位置に関して両者の感度が異なる
ことなどから、両者におけるノイズは異なった波形とな
る。よって、乗算、自乗和、Ｍ(x) とＥ(x) それぞれの
絶対値の和の演算を行うことにより、信号成分は強調さ
れ、ノイズ成分は相殺されて、Ｓ／Ｎ比が向上する。ま
た、Ｍ(x) とＥ(x) のそれぞれの絶対値のうち小さい方
を取る演算では、欠陥部では渦流信号、漏洩信号とも大
きな値をとるため、小さい方を取るという演算の結果も
さほど小さくならないのに対し、ノイズ部はどちらか一
方が小さくなること場合があり、小さい方を取ること
で、演算結果はかなり小さくなる可能性がある。そのた
め、相対的には欠陥部がノイズ部に比べて強調される。Signal changes due to defects are expected to be at the same position in the eddy current flaw detection method and the leakage magnetic flux flaw detection method, but for noise, the two use different phenomena.
Due to the difference in sensitivity between the two with respect to the position of the noise source in the thickness direction, the noise in both has different waveforms. Therefore, by performing the multiplication, the sum of squares, and the operation of the sum of the absolute values of M (x) and E (x), the signal component is emphasized, the noise component is canceled, and the S / N ratio is improved. In addition, in the calculation that takes the smaller one of the absolute values of M (x) and E (x), both the eddy current signal and the leakage signal take a larger value at the defective portion, so the calculation result that the smaller one is taken is also very large. While the noise portion does not decrease, there is a case where one of the noise portions becomes smaller. By taking the smaller one, the calculation result may be considerably smaller. Therefore, the defective portion is relatively emphasized as compared with the noise portion.
【００１９】演算の方式については、渦流探傷法、漏洩
磁束探傷法の両者で似通った欠陥信号が強められ、一方
両者で必ずしも同じ位置、あるいは同じ波形として現れ
ないノイズが相対的に弱められる演算であればよい。演
算の方式については、ノイズや欠陥信号の性質に応じ
て、また、装置化する上での制約などに応じて、適宜選
択することが可能である。The method of calculation is such that the defect signal similar in both the eddy current flaw detection method and the leakage magnetic flux flaw detection method is strengthened, while the noise which does not necessarily appear in the same position or the same waveform is relatively weakened in both methods. I just need. The calculation method can be appropriately selected according to the nature of the noise and the defect signal, and according to the restrictions in realizing the device.
【００２０】また、前記説明においては、１種類の渦流
探傷信号と１種類の漏洩磁束探傷信号間の演算を例に取
り説明したが、１種類に限る必要はない。多くの、測定
条件の異なる信号を使用することで、信号は強調され、
ノイズは相対的に強調の程度が少なくなるという効果
が、増すことが期待できる。渦流法の場合には、測定条
件として、励磁周波数、位相検波の際の位相、薄い金属
帯の場合どちらの面から探傷するかなどがあり、測定条
件を変えることで信号とノイズの出方を変化させること
が可能である。漏洩磁束探傷法に関しても同様で、リフ
トオフ、どちらの面から探傷するかなど、測定条件を変
えたデータを使うことができる。たとえば、Ｍ１(x) 、
Ｍ２(x) を異なる条件でとった漏洩磁束探傷信号データ
とし、Ｅ１(x) 、Ｅ２(x) を異なる条件でとった渦流探
傷信号とすると、以下の（２）式に示すＢ(x) を、欠陥
の有無の判定に使用できる。 Ｂ(x) ＝abs[Ｍ１(x) ×Ｅ１(x) ×Ｅ２(x)]＋abs[Ｍ２(x)] …… （２） ここで、abs[x]はx の絶対値をとる関数である。In the above description, the calculation between one kind of eddy current flaw detection signal and one kind of leakage magnetic flux flaw detection signal has been described as an example, but it is not limited to one kind. By using many signals with different measurement conditions, the signal is emphasized,
It can be expected that the effect that the degree of emphasis of noise becomes relatively small increases. In the case of the eddy current method, the measurement conditions include the excitation frequency, phase during phase detection, and from which surface to detect flaws in the case of a thin metal band, etc. It is possible to change. The same applies to the magnetic flux leakage inspection method, and data obtained by changing measurement conditions such as lift-off and from which surface to inspect can be used. For example, M1 (x),
Assuming that M2 (x) is leak magnetic flux inspection signal data obtained under different conditions and E1 (x) and E2 (x) are eddy current inspection signals obtained under different conditions, B (x) shown in the following equation (2) is obtained. Can be used to determine the presence or absence of a defect. B (x) = abs [M1 (x) × E1 (x) × E2 (x)] + abs [M2 (x)] (2) where abs [x] is a function that takes the absolute value of x. is there.
【００２１】また、ここでは渦流探傷信号、漏洩磁束探
傷信号のある一種類の演算結果を欠陥の有無の判定に使
用する場合について述べているが、これは一つに限ら
ず、２つ以上を使うことも可能である。たとえば、上記
Ａ(x) とＢ(x) それぞれの判定結果を組み合わせて最終
的な判定をくだすことも可能である。また、従来の渦流
探傷信号単体and/or漏洩磁束探傷信号単体での判定をも
加えることができる。In this case, a case where one kind of calculation result of the eddy current flaw detection signal and the leakage magnetic flux flaw detection signal is used to determine the presence or absence of a defect is described. It is also possible to use. For example, a final determination can be made by combining the determination results of A (x) and B (x). In addition, it is possible to add a judgment based on a conventional eddy current flaw detection signal alone and / or a leakage magnetic flux flaw detection signal alone.
【００２２】[0022]
【実施例】以下、本発明の実施例を図を用いて説明す
る。図１は、本発明にかかる装置の１例を示す図であ
る。図１において、１１は鋼板、１２はＥ型コアを用い
たセンサ（Ｅ型センサ）、１２ａ、１２ｂ、１２ｃはＥ
型センサの足（磁極）、１２ｄ、１２ｅ、１２ｆは各足
に巻かれたコイル、１３は直流磁化装置、１４は励磁信
号発生装置、１５は位相検波装置、１６、１７はバンド
パスフィルタ、１８は総合探傷信号演算器である乗算
器、１９は判定回路である。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an example of an apparatus according to the present invention. In FIG. 1, 11 is a steel plate, 12 is a sensor using an E-type core (E-type sensor), 12a, 12b, and 12c are E-type sensors.
The feet (magnetic poles) of the type sensor, 12d, 12e and 12f are coils wound around each foot, 13 is a DC magnetizing device, 14 is an excitation signal generator, 15 is a phase detector, 16 and 17 are bandpass filters, 18 Is a multiplier which is an integrated flaw detection signal calculator, and 19 is a judgment circuit.
【００２３】鋼板１１を挟んで、一方の側にＥ型センサ
１２を、もう一方の側に直流磁化装置１３を配置する。
この直流磁化装置１３により、鋼板１１の被検査部位は
飽和域まで磁化される。鋼板１１は、Ｅ型センサ１２と
磁化器１３の間を移動するが、その移動方向に沿ってセ
ンサコアの３本の足１２ａ，１２ｂ，１２ｃが並んでい
る。その３本のうち、Ｅ型センサの中心の足１２ｂに巻
いてあるコイル１２ｅは磁気検出部として使用されてお
り、そのコイルに鎖交する磁束の時間微分値が計測され
ることにより、漏洩磁束信号、および渦流信号が検出さ
れる。コアがＥ型であるという構造上の特徴から、その
コイルに鎖交する磁束は、一方の端部の足１２ａと真中
の足１２ｂを含む磁気的なループを通る磁束と、もう一
方の端部の足１２ｃと真中の足１２ｂを含む磁気的なル
ープを通る磁束との差分となる。そのため、両ループに
共通のノイズ成分などはキャンセルされ、両ループで共
通でない欠陥信号成分が選択的に検出されることにな
る。With the steel plate 11 interposed, an E-type sensor 12 is arranged on one side, and a DC magnetizing device 13 is arranged on the other side.
The DC magnetizing device 13 magnetizes the inspected portion of the steel plate 11 to the saturation region. The steel plate 11 moves between the E-type sensor 12 and the magnetizer 13, and the three legs 12a, 12b, and 12c of the sensor core are arranged along the moving direction. Of these three coils, the coil 12e wound on the center foot 12b of the E-type sensor is used as a magnetic detection unit, and the time differential value of the magnetic flux interlinking the coil is measured, so that the leakage magnetic flux is measured. A signal and an eddy current signal are detected. Due to the structural feature that the core is E-shaped, the magnetic flux linked to the coil is divided into a magnetic flux passing through a magnetic loop including the foot 12a and the middle foot 12b at one end and a magnetic flux linked to the other end. And the magnetic flux passing through the magnetic loop including the middle foot 12b. Therefore, a noise component common to both loops is canceled, and a defective signal component not common to both loops is selectively detected.
【００２４】一方、両端の２本の足に巻かれたコイル１
２ｄ，１２ｆは、励磁信号発生装置１４により励磁さ
れ、渦流励磁用として使用される。両者の励磁の位相差
は様々なものを選択可能であるが、ここでは、一方の足
から出た磁束がもう一方の足に戻るような位相差（位相
差１８０度）を用いて、両者の足１２ａ，１２ｃから出
る磁束が作り出す渦電流がちょうど真ん中の検出用のコ
イル１２ｅの真下で強められるようにしている。コイル
１２ｅの出力を位相検波装置１５およびバンドパスフィ
ルタ１６に通すことで、渦流探傷信号を得ることができ
る。また、コイル１２ｅの出力を、適当なバンドパスフ
ィルタ１７に通すことで、漏洩磁束探傷信号（微分値）
を得ることができる。On the other hand, a coil 1 wound on two legs at both ends
2d and 12f are excited by the excitation signal generator 14 and used for eddy current excitation. Various phase differences can be selected for the excitation between the two legs. Here, a phase difference (a phase difference of 180 degrees) in which the magnetic flux from one leg returns to the other leg is used. The eddy current generated by the magnetic flux from the legs 12a and 12c is strengthened just below the detection coil 12e in the middle. By passing the output of the coil 12e through the phase detector 15 and the bandpass filter 16, an eddy current flaw detection signal can be obtained. Further, by passing the output of the coil 12e through an appropriate band-pass filter 17, the leakage magnetic flux detection signal (differential value) is obtained.
Can be obtained.
【００２５】バンドパスフィルタ１６、１７の出力は、
乗算器１８で掛算される。判定回路１９は、掛算器１８
の出力の大きさに応じて欠陥の有無と程度を判定する。The outputs of the band pass filters 16 and 17 are
The multiplication is performed by the multiplier 18. The judgment circuit 19 includes a multiplier 18
The presence / absence and degree of a defect are determined according to the magnitude of the output.
【００２６】図２に、図１の装置によって得られる信号
の波形の例を示す。図２において、(a) は渦流探傷信号
Ｅ(x) 、(b) は漏洩磁束探傷信号Ｍ(x) 、(c) はＥ(x)
×Ｍ(x) の波形を示す。横軸は、鋼板上の位置ｘを示
す。FIG. 2 shows an example of the waveform of a signal obtained by the apparatus shown in FIG. In FIG. 2, (a) is an eddy current flaw detection signal E (x), (b) is a leakage magnetic flux flaw detection signal M (x), and (c) is E (x)
The waveform of × M (x) is shown. The horizontal axis indicates the position x on the steel plate.
【００２７】渦流探傷信号Ｅ(x) においては、欠陥部で
信号が大きくなっているだけでなく、検査体に起因する
地合ノイズが大きく出ているため、Ｓ／Ｎ比は1.5程度
である。漏洩磁束探傷信号Ｍ(x) も、渦流探傷信号と同
じ位置に欠陥信号が出ているが、検査体に起因する地合
ノイズがあるため、Ｓ／Ｎ比はやはり1.5程度である。In the eddy current flaw detection signal E (x), not only the signal is large at the defective part but also the formation noise caused by the inspection object is large, so that the S / N ratio is about 1.5. . The leakage magnetic flux detection signal M (x) also has a defect signal at the same position as the eddy current detection signal, but the S / N ratio is still about 1.5 due to formation noise caused by the inspection object.
【００２８】Ｅ(x) ×Ｍ(x) においては、欠陥信号は、
両信号で現れる位置がほぼ同じであるため、かけ算をす
ることで、演算後の信号は大きくなる。一方、地合ノイ
ズの出方は、渦流探傷信号、漏洩磁束探傷信号で異なる
ため、両者の信号が、必ずしも同じ位置で大きくなると
は限らず、かけ算をしたとしても、演算後の信号は、欠
陥信号部同士の場合に比べて大きくならない。つまり、
欠陥信号部は、地合ノイズ部に比べ強調されるので、Ｓ
／Ｎ比は3.5 に向上している。In E (x) × M (x), the defect signal is
Since the positions appearing in both signals are substantially the same, the signal after the operation becomes large by performing the multiplication. On the other hand, the formation noise is different between the eddy current flaw detection signal and the leakage magnetic flux flaw detection signal.Therefore, both signals do not always increase at the same position. It does not become larger than in the case of signal parts. That is,
Since the defective signal portion is emphasized compared to the formation noise portion, S
The / N ratio has improved to 3.5.
【００２９】この例では、渦流励磁用コイルを持ったＥ
型センサを、渦流探傷用、漏洩磁束探傷用兼用のセンサ
として用いたが、兼用する必要は必ずしもなく、これら
は別々に設けることが可能である。ただし、同じ検査部
位からの信号同士が演算に使用されるように、信号相互
の時間差を考慮する必要がある。In this example, an E with an eddy current exciting coil
Although the type sensor was used as a sensor for eddy current flaw detection and a sensor for leak magnetic flux flaw detection, it is not always necessary to use the same type of sensor, and these can be provided separately. However, it is necessary to consider the time difference between the signals so that the signals from the same inspection part are used for the calculation.
【００３０】また、渦流探傷法と漏洩磁束探傷法で、実
質的に同じ位置からの信号同士の演算を行うわけである
が、この位置というのは探傷面から見た場合の２次元的
な位置であり、たとえば薄い金属帯の場合で、表裏どち
ら側からでも探傷できる場合には、２次元的な位置が対
応していれば、図３に示すようにそれぞれのセンサ１２
ｇ，１２ｈの置かれる側が鋼板１１に対して表裏逆であ
ってもかまわない。欠陥信号が表裏から多少なりとも検
出できる場合には、渦流法と漏洩磁束法両者の計測原理
の違いによるノイズの出方の差に加えて、深さ方向の探
傷範囲の差による効果も加味されるため、渦流、漏洩両
信号のノイズの性質の違いをさらに強調することも可能
である。In addition, in the eddy current flaw detection method and the leakage magnetic flux flaw detection method, the calculation of signals from substantially the same position is performed, and this position is a two-dimensional position as viewed from the flaw detection surface. For example, in the case of a thin metal band and flaw detection can be performed from both the front and back sides, if the two-dimensional positions correspond to each other, as shown in FIG.
The side where g and 12h are placed may be upside down with respect to the steel plate 11. If any defect signal can be detected from the front and back, the effect due to the difference in the flaw detection range in the depth direction is taken into account in addition to the difference in the way noise is generated due to the difference in the measurement principle between the eddy current method and the leakage magnetic flux method. Therefore, it is possible to further emphasize the difference in the noise characteristics between the eddy current and the leaked signal.
【００３１】また、演算をする際には、渦流探傷信号、
漏洩磁束探傷信号それぞれにバンドパスフィルタをかけ
ることが、Ｓ／Ｎ比向上の観点から効果的である。どの
周波数帯域を選択するかは、渦流探傷信号、漏洩磁束探
傷信号それぞれに独立に選ぶことが可能であるが、両者
で実質的に同じバンドパスフィルタを選択することで、
信号がよく強調されることがある。それは、同じバンド
パスフィルタを選ぶことで、欠陥部での渦流探傷信号と
漏洩磁束探傷信号の形が似たものとなり、欠陥信号が強
調されやすくなるからである。When performing the calculation, an eddy current detection signal,
It is effective to apply a band-pass filter to each of the leakage magnetic flux detection signals from the viewpoint of improving the S / N ratio. Which frequency band to select can be selected independently for each of the eddy current flaw detection signal and the leakage magnetic flux flaw detection signal, but by selecting substantially the same bandpass filter for both,
Sometimes the signal is well emphasized. This is because, by selecting the same bandpass filter, the shape of the eddy current flaw detection signal and the shape of the leakage magnetic flux flaw detection signal at the defect portion become similar, and the defect signal is easily emphasized.
【００３２】ここでＥ型センサを使用したのは、Ｅ型セ
ンサが欠陥検出能力が高いだけでなく、渦流探傷信号と
漏洩磁束探傷信号両者を一つのセンサで計測できるとい
うメリットがあるからである。渦流、漏洩磁束両方の信
号を必要とする本発明においては、システムの簡略化が
図れるわけである。また、検査体の実質的に同じ位置か
らの信号は時間的に同時に得られるため、時間的をずら
すことなく、検査体の同じ位置からの信号同士を使った
演算が容易である。The reason why the E-type sensor is used here is that the E-type sensor has a merit that not only the defect detection ability is high but also that the eddy current flaw detection signal and the leakage magnetic flux flaw detection signal can be measured by one sensor. . In the present invention which requires signals of both the eddy current and the leakage magnetic flux, the system can be simplified. Further, since signals from substantially the same position on the test object are obtained at the same time in time, calculation using signals from the same position on the test object can be easily performed without shifting the time.
【００３３】[0033]
【発明の効果】本発明においては、１種類以上の漏洩探
傷信号と１種類以上の渦流探傷信号の、実質的に同一の
検査部位から得られた信号波形同士を演算して得られる
複合探傷信号を用いて欠陥の有無や有害度を判定してい
るので、従来の方法ではＳ／Ｎ比が十分取れず検出しに
くい欠陥を、Ｓ／Ｎよく検出することができる。According to the present invention, a composite flaw detection signal obtained by calculating signal waveforms obtained from substantially the same inspection site of one or more kinds of leakage flaw detection signals and one or more kinds of eddy current flaw detection signals. Is used to determine the presence / absence and harmfulness of a defect. Therefore, it is possible to detect a defect having a sufficient S / N ratio and difficult to be detected by the conventional method with a good S / N ratio.
【図１】 本発明の装置の１実施例を示す図である。FIG. 1 is a diagram showing one embodiment of the apparatus of the present invention.
【図２】 渦流信号と漏洩磁束信号、及びその積信号の
波形の例をを示す図である。FIG. 2 is a diagram illustrating an example of waveforms of an eddy current signal, a leakage magnetic flux signal, and a product signal thereof.
【図３】 薄い磁性金属帯を、渦流法、漏洩磁束法別々
のセンサで、表裏反対側から探傷する場合のセンサ配置
例を示す図である。FIG. 3 is a diagram showing an example of sensor arrangement in the case where a thin magnetic metal band is flaw-detected from the front and back opposite sides using separate sensors for an eddy current method and a leakage magnetic flux method.
【図４】 従来技術の例を示す図である。FIG. 4 is a diagram showing an example of the related art.
【図５】 従来技術の例を示す図である。FIG. 5 is a diagram showing an example of the related art.
【図６】 従来技術の例を示す図である。FIG. 6 is a diagram showing an example of the related art.
１１ 鋼板 １２ Ｅ型センサ １３ 直流磁化装置 １４ 励磁信号発生装置 １５ 位相検波装置 １６、１７ バンドパスフィルタ １８ 乗算器 １９ 判定回路 DESCRIPTION OF SYMBOLS 11 Steel plate 12 E type sensor 13 DC magnetizing device 14 Excitation signal generator 15 Phase detector 16 and 17 Band pass filter 18 Multiplier 19 Judgment circuit
フロントページの続き (56)参考文献 特開 平８−83507（ＪＰ，Ａ) 特開 平５−164745（ＪＰ，Ａ) 特開 昭63−235854（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01N 27/72 - 27/90 特許ファイル（ＰＡＴＯＬＩＳ)(56) References JP-A-8-83507 (JP, A) JP-A-5-164745 (JP, A) JP-A-63-235854 (JP, A) (58) Fields studied (Int .Cl. 7 , DB name) G01N 27/72-27/90 Patent file (PATOLIS)
Claims (10)
に検査部に渦電流を発生させる工程、(2) 磁性金属体の
欠陥から発生する漏洩磁束を磁気センサにより検出して
漏洩磁束探傷信号を得る工程、(3) 渦電流が磁性金属体
の欠陥により乱れることにより生ずる磁場を磁気センサ
により検出して渦流検出信号を得、これを位相検波して
渦流探傷信号を得る工程、(4) 少なくとも一つの測定条
件における漏洩磁束探傷信号と少なくとも一つの測定条
件における渦流探傷信号の、実質的に同一の検査部位か
ら得られた信号波形同士に対し、当該複数の信号波形中
に共通して存在する欠陥信号をノイズ信号に対して相対
的に強調するような演算を含む信号処理を行って得られ
る複合探傷信号を用いて、磁性金属体の欠陥を検出する
工程、を備えたことを特徴とする磁性金属体の探傷方
法。(1) a step of magnetizing an inspection part of a magnetic metal body and generating an eddy current in the inspection part; and (2) a leakage magnetic flux generated by detecting a leakage magnetic flux generated from a defect of the magnetic metal body by a magnetic sensor. A step of obtaining a flaw detection signal, (3) a step of detecting a magnetic field generated by the eddy current being disturbed by a defect of the magnetic metal body by a magnetic sensor to obtain an eddy current detection signal, and phase-detecting this to obtain an eddy current flaw detection signal, 4) For the signal waveforms obtained from substantially the same inspection site, the leakage magnetic flux inspection signal under at least one measurement condition and the eddy current inspection signal under at least one measurement condition are common to the plurality of signal waveforms. Detecting a defect in the magnetic metal body using a composite flaw detection signal obtained by performing a signal processing including an operation of relatively emphasizing the existing defect signal with respect to the noise signal. Special Testing method of magnetic metal body to be.
相、励磁信号の周波数、探傷面の３つの測定条件のうち
少なくとも１条件が異なる複数の渦流探傷信号であるこ
とを特徴とする請求項１に記載の磁性金属体の探傷方
法。2. The eddy current detection signal according to claim 1, wherein the eddy current detection signal is a plurality of eddy current flaw detection signals different in at least one of three measurement conditions of a phase in phase detection, a frequency of an excitation signal, and a flaw detection surface. The flaw detection method for a magnetic metal body according to the above.
数帯域と渦流探傷信号の周波数帯域をほぼ一致させるよ
うにしたことを特徴とする請求項１又は請求項２に記載
の磁性金属体の探傷方法。3. The flaw detection of a magnetic metal body according to claim 1, wherein the frequency band of the leakage magnetic flux flaw detection signal on which the calculation is performed and the frequency band of the eddy current flaw detection signal are made to substantially coincide with each other. Method.
渦流検出信号の一組を得ることを特徴とする請求項１な
いし請求項３のいずれか１項に記載の磁性金属体の探傷
方法。4. The flaw detection method for a magnetic metal body according to claim 1, wherein one set of a magnetic flux detection signal and a eddy current detection signal are obtained by one magnetic sensor.
い、渦流探傷をそれと反対の面から行うことを特徴とす
る請求項１ないし請求項３のいずれか１項に記載の磁性
金属体の探傷方法。5. The magnetic metal body according to claim 1, wherein the magnetic flux leakage inspection is performed from one surface of the metal body, and the eddy current inspection is performed from the opposite surface. Flaw detection method.
号を強調するような演算が、少なくとも一つの漏洩磁束
探傷信号と少なくとも一つの渦流探傷信号との乗算を含
むことを特徴とする請求項１ないし請求項５のうちいず
れか１項に記載の磁性金属体の探傷方法。6. The method according to claim 1, wherein the operation of enhancing a signal commonly present in a plurality of signal waveforms includes a multiplication of at least one leakage magnetic flux detection signal and at least one eddy current detection signal. 6. The flaw detection method for a magnetic metal body according to claim 1.
陥信号をノイズ信号に対して相対的に強調するような演
算が、少なくとも一つの漏洩磁束探傷信号の絶対値と少
なくとも一つの渦流探傷信号の絶対値との加算を含むこ
とを特徴とする請求項１ないし請求項５のうちいずれか
１項に記載の磁性金属体の探傷方法。7. An operation for emphasizing a defect signal which is present in common among a plurality of signal waveforms relative to a noise signal is performed by using an absolute value of at least one leakage magnetic flux detection signal and at least one eddy current inspection. The flaw detection method for a magnetic metal body according to any one of claims 1 to 5 , further comprising adding an absolute value of the signal.
陥信号をノイズ信号に対して相対的に強調するような演
算が、少なくとも一つの漏洩磁束探傷信号の自乗値と少
なくとも一つの渦流探傷信号の自乗値との加算を含むこ
とを特徴とする請求項１ないし請求項５のうちいずれか
１項に記載の磁性金属体の探傷方法。8. A calculation for emphasizing a defect signal commonly present in a plurality of signal waveforms relative to a noise signal includes calculating a square value of at least one leakage magnetic flux detection signal and at least one eddy current inspection. testing method of a magnetic metal body according to any one of claims 1 to claim 5, characterized in that it comprises the addition of the square value of the signal.
陥信号をノイズ信号に対して相対的に強調するような演
算が、少なくとも一つの漏洩磁束探傷信号の絶対値と少
なくとも一つの渦流探傷信号の絶対値のうち最も小さい
ものを選択するものであることを特徴とする請求項１な
いし請求項５のうちいずれか１項に記載の磁性金属体の
探傷方法。9. An operation for emphasizing a defect signal commonly present in a plurality of signal waveforms relative to a noise signal is performed by an absolute value of at least one leakage magnetic flux inspection signal and at least one eddy current inspection. The smallest of the absolute values of the signal
Testing method of a magnetic metal body according to any one of claims 1 to claim 5, characterized in that it is used to select one.
装置、(2) Ｅ型形状の強磁性体で作られＥ型を成す３個
の磁極の列が磁性金属体との相対的運動方向に沿うよう
に配置されたＥ型コア、およびＥ型コアの３個の磁極に
それぞれ巻いた３個のコイルとを有してなるＥ型磁気セ
ンサ、(3) 前記Ｅ型コアの３個のコイルの内の両端のコ
イルに交流の励磁信号を印加するための少なくとも一つ
の励磁信号発生装置、(4) 前記Ｅ型コアの中央のコイル
から検出信号を取り出し、この検出信号から励磁信号と
同じ周波数成分を除去して漏洩磁束探傷信号を得るため
の漏洩磁束探傷信号用フィルタ、(5) 前記Ｅ型コアの中
央のコイルからの検出信号を位相検波して渦流探傷信号
を得るための少なくとも一つの位相検波器、(6) 実質的
に同一の検査部位から得られた前記漏洩磁束探傷信号と
前記渦流探傷信号の波形中に共通して存在する欠陥信号
をノイズ信号に対して相対的に強調するような演算を含
む信号処理を行って総合探傷信号を得るための総合探傷
信号演算器、(7) 総合探傷信号演算器の出力に基づいて
磁性金属体の欠陥の有無または欠陥の等級を判断するた
めの判定回路、とを有してなる磁性金属体探傷装置。10. A magnetizing device for magnetizing a magnetic metal body to be inspected, and (2) a row of three E-shaped magnetic poles made of an E-shaped ferromagnetic material and having a row relative to the magnetic metal body. (3) an E-shaped magnetic sensor comprising: an E-shaped core arranged along the direction of movement; and three coils respectively wound around three magnetic poles of the E-shaped core. At least one excitation signal generator for applying an AC excitation signal to the coils at both ends of the plurality of coils, (4) extracting a detection signal from a central coil of the E-shaped core, and extracting an excitation signal from the detection signal. (5) a filter for a leakage magnetic flux detection signal for obtaining a leakage magnetic flux detection signal by removing the same frequency component as that described above, and (5) for detecting an eddy current detection signal by performing phase detection on a detection signal from a center coil of the E-shaped core. At least one phase detector, (6) obtained from substantially the same To perform a signal processing including an operation of emphasizing a defect signal which is present in the waveforms of the leakage magnetic flux detection signal and the eddy current detection signal relative to a noise signal to obtain a total flaw detection signal. A magnetic metal inspection apparatus comprising: a general flaw detection signal arithmetic unit; and (7) a determination circuit for determining the presence or absence of a defect in the magnetic metal body or the grade of the defect based on the output of the general flaw detection signal arithmetic unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP08350696A JP3307220B2 (en) | 1996-04-05 | 1996-04-05 | Method and apparatus for flaw detection of magnetic metal body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP08350696A JP3307220B2 (en) | 1996-04-05 | 1996-04-05 | Method and apparatus for flaw detection of magnetic metal body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09274018A JPH09274018A (en) | 1997-10-21 |
| JP3307220B2 true JP3307220B2 (en) | 2002-07-24 |
Family
ID=13804375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP08350696A Expired - Fee Related JP3307220B2 (en) | 1996-04-05 | 1996-04-05 | Method and apparatus for flaw detection of magnetic metal body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3307220B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005016566A1 (en) * | 2003-08-13 | 2005-02-24 | Jfe Steel Corporation | Method of manufacturing steel strip or surface-treated steel strip |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4552680B2 (en) * | 2005-02-10 | 2010-09-29 | Ｊｆｅスチール株式会社 | Metal strip manufacturing method and marking metal strip |
| CN101978261B (en) * | 2008-04-14 | 2012-06-13 | 三菱电机株式会社 | Wire rope flaw detector |
| JP5373665B2 (en) * | 2010-03-02 | 2013-12-18 | 株式会社Ｉｈｉ検査計測 | Nondestructive inspection equipment |
| CN110308200B (en) * | 2019-07-16 | 2022-11-04 | 南京航空航天大学 | Differential magnetic leakage and eddy current composite high-speed rail flaw detection method |
| CN113532255B (en) * | 2021-07-27 | 2024-01-12 | 爱德森（厦门）电子有限公司 | Method and device for detecting thickness of magnetic leakage and eddy current |
-
1996
- 1996-04-05 JP JP08350696A patent/JP3307220B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005016566A1 (en) * | 2003-08-13 | 2005-02-24 | Jfe Steel Corporation | Method of manufacturing steel strip or surface-treated steel strip |
| CN1311235C (en) * | 2003-08-13 | 2007-04-18 | 杰富意钢铁株式会社 | Method of manufacturing steel strip or surface-treated steel strip |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09274018A (en) | 1997-10-21 |
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