JPH01119757A - Magnetic method of flaw detection - Google Patents
Magnetic method of flaw detectionInfo
- Publication number
- JPH01119757A JPH01119757A JP27866787A JP27866787A JPH01119757A JP H01119757 A JPH01119757 A JP H01119757A JP 27866787 A JP27866787 A JP 27866787A JP 27866787 A JP27866787 A JP 27866787A JP H01119757 A JPH01119757 A JP H01119757A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- flaw detection
- inspected
- defect
- voltage
- 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.)
- Granted
Links
- 238000001514 detection method Methods 0.000 title claims abstract description 39
- 238000000034 method Methods 0.000 title claims abstract description 11
- 230000007547 defect Effects 0.000 claims abstract description 44
- 239000000463 material Substances 0.000 claims abstract description 44
- 230000004907 flux Effects 0.000 claims abstract description 24
- 230000005415 magnetization Effects 0.000 claims abstract description 18
- 238000004458 analytical method Methods 0.000 claims abstract description 6
- 230000002950 deficient Effects 0.000 claims description 19
- 239000000284 extract Substances 0.000 claims 1
- 230000001360 synchronised effect Effects 0.000 description 18
- 238000010586 diagram Methods 0.000 description 12
- 229910000831 Steel Inorganic materials 0.000 description 5
- 238000003754 machining Methods 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 238000012360 testing method Methods 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 2
- 238000009659 non-destructive testing Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 229920000742 Cotton Polymers 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は被検査材、例えば鋼管の内外面に発生する欠陥
を高精度で検出し得るようにした磁気探傷法に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic flaw detection method that allows defects occurring on the inner and outer surfaces of a material to be inspected, such as a steel pipe, to be detected with high precision.
（従来の技術）
従来から、被検査材例えば鋼管の内外面に発生する欠陥
を探傷する方法としては、超音波を用いた超音波探傷法
、電磁誘導法を適用した渦電流探傷法、鋼管を磁化して
欠陥部から漏洩する磁束を検知する磁気探傷法、あるい
は鋼管にＸ線を照射してその透過量の変化から欠陥を検
出するＸ線探傷法等の方法がある。(Prior art) Traditionally, methods for detecting defects that occur on the inner and outer surfaces of materials to be inspected, such as steel pipes, include ultrasonic flaw detection using ultrasonic waves, eddy current flaw detection using electromagnetic induction, and flaw detection for steel pipes. There are methods such as magnetic flaw detection, which detects magnetic flux that is magnetized and leaks from defective parts, and X-ray flaw detection, which irradiates a steel pipe with X-rays and detects defects from changes in the amount of X-rays transmitted.
第８図は、磁気探傷法の原理を示す概要構成図である。FIG. 8 is a schematic diagram showing the principle of magnetic flaw detection.
第８図において、１は電磁石、２は鋼管等の被検査材、
３は被検査材２に存在子る欠陥部、４は磁気センサー、
５は直流磁化電源、６は電磁石ヨーク、７は欠陥部３か
ら発生する漏洩磁束を夫々示すものである。In Fig. 8, 1 is an electromagnet, 2 is a material to be inspected such as a steel pipe,
3 is a defect existing in the material to be inspected 2; 4 is a magnetic sensor;
Reference numeral 5 indicates a DC magnetization power supply, 6 indicates an electromagnetic yoke, and 7 indicates leakage magnetic flux generated from the defective portion 3, respectively.
第８図を用いて、磁気探傷法の原理を説明する。The principle of magnetic flaw detection will be explained using FIG.
すなわち、電磁石１の電磁石ヨーク６の上側に被検査材
２をセットし、直流磁化電源５から直流電流を供給して
被検査材２を磁化すると、欠陥部３は健全部と比較して
磁気抵抗が大きいため、欠陥部３から漏洩磁束７が発生
する。この漏洩磁束７の一部は、被検査材２の上側にも
漏洩する。そこで、磁気センサー４を図示矢印方向に移
動して欠陥部３上を通過させると、欠陥部３から発生す
る漏洩磁束７に比例した信号電圧が磁気センサー４にて
得られる。そして、この磁気センサー４にて得られた信
号電圧を、メーターあるいは記録計等で計測することに
より、被検査材２に存在する欠陥を間接的に検出するこ
とができる。なお、この磁気探傷法の公知技術の詳細な
内容については、例えば“非破壊検査便覧（非破壊検査
協会綿）の第■編（５７３頁〜６４４頁）“に開示され
ている。That is, when the inspected material 2 is set above the electromagnet yoke 6 of the electromagnet 1 and the inspected material 2 is magnetized by supplying DC current from the DC magnetization power source 5, the defective part 3 has a lower magnetic resistance than the healthy part. Since this is large, leakage magnetic flux 7 is generated from the defective portion 3. A part of this leakage magnetic flux 7 also leaks to the upper side of the material 2 to be inspected. Therefore, when the magnetic sensor 4 is moved in the direction of the arrow shown in the figure and passes over the defective portion 3, a signal voltage proportional to the leakage magnetic flux 7 generated from the defective portion 3 is obtained at the magnetic sensor 4. By measuring the signal voltage obtained by the magnetic sensor 4 with a meter or recorder, defects existing in the material to be inspected 2 can be indirectly detected. The detailed contents of the known technology of this magnetic flaw detection method are disclosed, for example, in "Nondestructive Testing Handbook (Nondestructive Testing Association Cotton), Volume 2 (pages 573 to 644)".
（発明が解決しようとする問題点）
しかしながら、上述したような従来の磁気探傷法では、
次に述べるような問題がある。すなわち、被検査材２に
仮に欠陥部３が存在していなくとも、機械加工歪みや熱
歪みが存在すると、これらの歪みにより磁気抵抗が健全
部と比較して増減することから、ノイズ電圧が発生して
Ｓ／Ｎ比を低下させる。このため、高精度の探傷を行な
うことが不可能となってしまう。(Problems to be solved by the invention) However, in the conventional magnetic flaw detection method as described above,
There are problems as described below. In other words, even if there is no defective part 3 in the inspected material 2, if machining distortion or thermal distortion exists, the magnetic resistance increases or decreases due to these distortions compared to a healthy part, and a noise voltage is generated. to reduce the S/N ratio. This makes it impossible to perform highly accurate flaw detection.
本発明は上記のような問題を解決するために成されたも
ので、機械加工歪みや熱歪みによるノイズ電圧を除去し
極めて高精度の探傷を行なうことが可能な磁気探傷法を
提供することを目的とする。The present invention was made in order to solve the above-mentioned problems, and aims to provide a magnetic flaw detection method that can remove noise voltages caused by machining distortion and thermal distortion and perform flaw detection with extremely high precision. purpose.
（問題点を解決するための手段）
上記の目的を達成するために本発明では、被検査材を磁
化し、欠陥部から発生する漏洩磁束を磁気センサーで検
知して欠陥を検出する磁気探傷法において、磁化方法と
して交流磁化を使用し、磁気センサーからの出力信号を
位相解析して欠陥信号を抽出するようにしている。(Means for Solving the Problems) In order to achieve the above object, the present invention uses a magnetic flaw detection method in which defects are detected by magnetizing the inspected material and detecting leakage magnetic flux generated from the defective part with a magnetic sensor. In this method, alternating current magnetization is used as the magnetization method, and defect signals are extracted by phase analysis of the output signal from the magnetic sensor.
（作用）
本発明においては、被検査材を交流磁化し、これによっ
て欠陥部から発生する漏洩磁束を磁気センサーで検知し
、その出力信号を位相解析することにより、ノイズ電圧
を分離除去して欠陥信号のみを抽出するようにしている
。従って、Ｓ／Ｎ比を向上させて、被検査材の欠陥を高
感度で検出することが可能となる。(Function) In the present invention, the material to be inspected is magnetized with alternating current, the leakage magnetic flux generated from the defective part is detected by a magnetic sensor, and the output signal is phase-analyzed to separate and remove the noise voltage and detect the defect. I am trying to extract only the signal. Therefore, it is possible to improve the S/N ratio and detect defects in the inspected material with high sensitivity.
本発明は、被検査材の磁気探傷法を行なう際に、被検査
材を磁化する時に交流磁界を用い、交流磁束の被検査材
への浸透深さによって磁束の位相が変化することに着目
して、欠陥による欠陥信号の電圧と擬似ノイズの電圧と
の位相差を解析し、擬似ノイズを分離除去するものであ
る。The present invention uses an alternating magnetic field to magnetize the inspected material when performing magnetic flaw detection on the inspected material, and focuses on the fact that the phase of the magnetic flux changes depending on the penetration depth of the alternating current magnetic flux into the inspected material. This method analyzes the phase difference between the voltage of the defect signal and the voltage of pseudo-noise caused by the defect, and separates and removes the pseudo-noise.
第１図は、本発明による磁気探傷法の基本原理を示す構
成図である。第１図に示すように、電磁石８の電磁石ヨ
ーク９の上側に被検査材１０をセットし、交流磁化電源
１１から交流電流を供給して被検査材１０を磁化する。FIG. 1 is a block diagram showing the basic principle of the magnetic flaw detection method according to the present invention. As shown in FIG. 1, a material to be inspected 10 is set above the electromagnet yoke 9 of an electromagnet 8, and an alternating current is supplied from an AC magnetization power source 11 to magnetize the material to be inspected.
この条件の下で、磁気センサー１２を図示矢印方向に移
動して欠陥部１３を通過させると、欠陥部１３による漏
洩磁束１４が磁気センサー１２と交差して欠陥信号が得
られる。次に、磁気センサー１２をさらに移動して機械
歪み部１５下を通過させると、機械歪みによる漏洩磁束
が発生しているので、磁気センサー１２にノイズ電圧が
発生する。これらの欠陥信号。Under this condition, when the magnetic sensor 12 is moved in the direction of the arrow shown in the figure and passes through the defective part 13, the leakage magnetic flux 14 due to the defective part 13 intersects with the magnetic sensor 12, and a defect signal is obtained. Next, when the magnetic sensor 12 is further moved to pass under the mechanical distortion section 15, a noise voltage is generated in the magnetic sensor 12 because leakage magnetic flux is generated due to the mechanical distortion. These defective signals.
ノイズ電圧は、信号増幅器１６で所期値に増幅される。The noise voltage is amplified to a desired value by the signal amplifier 16.
そして、この信号増幅器１６からの出力電圧は信号電圧
ベクトル解析器１７に入力され、交流磁化電源１１の基
準電圧と比較することにより、信号電圧ベクトル解析器
１７の出力端子に、Ｘ成分（ｅ ｓ ｃｏｓθ）とＹ成
分（ｅｓｓｌｎθ）の両成分に分解して出力される。The output voltage from the signal amplifier 16 is input to the signal voltage vector analyzer 17, and by comparing it with the reference voltage of the AC magnetizing power supply 11, the output terminal of the signal voltage vector analyzer 17 receives the X component (e s cos θ) and Y component (esslnθ) and output.
第２図は、欠陥と局部的な機械歪みによるノイズ電圧の
位相特性を示すものである。第２図に示すように、欠陥
信号の電圧と機械歪みによるノイズ電圧の振幅値の絶対
値を比較すると、ノイズ電圧の方が欠陥信号の約１．４
倍も大きい。しかし、位相特性を考慮すると、基準電圧
信号と同参目時。FIG. 2 shows the phase characteristics of noise voltage due to defects and local mechanical distortion. As shown in Figure 2, when comparing the absolute value of the amplitude value of the voltage of the defect signal and the noise voltage due to mechanical distortion, the noise voltage is approximately 1.4 times larger than that of the defect signal.
It's twice as big. However, when considering the phase characteristics, it is the same as the reference voltage signal.
欠陥信号はノイズ電圧と比較して２倍も大きい値である
。従って、信号増幅器１６からの出力電圧を位を目解析
することにより、Ｓ／Ｎ比の向上を図ることが可能とな
る。すなわち、割れや孔欠陥における磁気抵抗と電気抵
抗が、被検査材の健全部と比較して極端に大きいために
、漏洩磁束の位相は変化しないと考えられる。The defect signal is twice as large as the noise voltage. Therefore, by visually analyzing the output voltage from the signal amplifier 16, it is possible to improve the S/N ratio. That is, it is considered that the phase of the leakage magnetic flux does not change because the magnetic resistance and electrical resistance in cracks and hole defects are extremely large compared to the healthy parts of the inspected material.
（実施例）
以下、上述のような考え方に基づく本発明の一実施例に
ついて図面を参照して説明する。(Example) Hereinafter, an example of the present invention based on the above-mentioned idea will be described with reference to the drawings.
第３図は、本発明による磁気探傷法を実現するための一
実施例を示す構成図である。第３図において、１８は電
磁石、１９は電磁石ヨーク、２０は被検査材、２１は磁
気センサー、２２は信号増幅器、２３は同期検波器、２
４は交流磁化電源、２５は移相器を夫々示すものである
。FIG. 3 is a configuration diagram showing an embodiment for realizing the magnetic flaw detection method according to the present invention. In FIG. 3, 18 is an electromagnet, 19 is an electromagnet yoke, 20 is a material to be inspected, 21 is a magnetic sensor, 22 is a signal amplifier, 23 is a synchronous detector, 2
Reference numeral 4 indicates an AC magnetizing power supply, and reference numeral 25 indicates a phase shifter.
第３図を用いて磁気探傷法を説明する。すなわち、電磁
石１８の電磁石ヨーク１９の上側に被検査材２０をセッ
トし、交流磁化電源２４から交流電流を供給して被検査
材２０を磁化する。ここで、もし被検査材２０に欠陥が
存在すると、当該欠陥部から交流の漏洩磁束が発生する
。この漏洩磁束を、磁気センサー２１で電気信号に変換
する。この電気信号に変換された出力電圧は、信号増幅
器２２に入力されて所期値に増幅された後、同期検波器
２３に入力される。一方、同期検波器２３には交流磁化
電源２４の電圧が、移相器２５を介し基準電圧として入
力されている。そして同期検波器２３で、信号増幅器２
２からの出力電圧と、交流磁化電源１１の基準電圧とを
比較することによって、同期検波器２３の出力端子には
、両信号電圧の位相差θと、信号増幅器２２の出力電圧
ｅｓに対応した出力（ｅ ｓ ｃｏｓθ）が得られる。The magnetic flaw detection method will be explained using FIG. That is, the material to be inspected 20 is set above the electromagnet yoke 19 of the electromagnet 18, and the material to be inspected 20 is magnetized by supplying alternating current from the AC magnetization power source 24. Here, if a defect exists in the inspected material 20, an alternating current leakage magnetic flux is generated from the defective portion. This leakage magnetic flux is converted into an electrical signal by the magnetic sensor 21. The output voltage converted into an electrical signal is input to the signal amplifier 22 and amplified to a desired value, and then input to the synchronous detector 23. On the other hand, the voltage of the AC magnetizing power source 24 is inputted to the synchronous detector 23 via a phase shifter 25 as a reference voltage. Then, in the synchronous detector 23, the signal amplifier 2
By comparing the output voltage from 2 and the reference voltage of the AC magnetizing power supply 11, the output terminal of the synchronous detector 23 receives a signal corresponding to the phase difference θ between both signal voltages and the output voltage es of the signal amplifier 22. An output (es cos θ) is obtained.
従って、移相器２５の基準電圧の位相をノイズ電圧の位
相と９０度差に調整することにより、ノイズ電圧は除去
され、欠陥信号のみを高いＳ／Ｎ比で検出することがで
きる。Therefore, by adjusting the phase of the reference voltage of the phase shifter 25 to be 90 degrees different from the phase of the noise voltage, the noise voltage is removed and only the defective signal can be detected with a high S/N ratio.
上述したように本実施例では、被検査材２０を磁化し、
欠陥部から発生する漏洩磁束を磁気センサー２１で検知
して欠陥を検出する場合に、磁化方法として交流磁化電
源２４による交流磁花を使用し、磁気センサー２１で得
られた信号電圧を信号増幅器２２を介して、同期検波器
２５で位相解析して欠陥信号を抽出するようにしたもの
である。As described above, in this example, the material to be inspected 20 is magnetized,
When detecting a defect by detecting the leakage magnetic flux generated from the defective part with the magnetic sensor 21, an AC magnetic field produced by the AC magnetizing power supply 24 is used as the magnetization method, and the signal voltage obtained by the magnetic sensor 21 is sent to the signal amplifier 22. A synchronous detector 25 performs phase analysis to extract a defective signal.
従って、欠陥信号電圧とノイズ電圧との位相差により、
欠陥信号を分離して検出できるため、機械加工歪みや熱
歪みによるノイズ電圧を除去し、Ｓ／Ｎ比を向上させて
極めて高精度に欠陥の探傷を行なうことが可能となる。Therefore, due to the phase difference between the defect signal voltage and the noise voltage,
Since defect signals can be detected separately, noise voltages due to machining distortion and thermal distortion can be removed, the S/N ratio can be improved, and defects can be detected with extremely high precision.
因みに、本実施例の方法では従来方法に比較して、・Ｓ
／Ｎ比を５倍以上向上させることができる。Incidentally, in the method of this embodiment, compared to the conventional method, ・S
/N ratio can be improved by 5 times or more.
第４図は、ボイラチューブ等に使用するシームレスパイ
プの探傷法に適用した場合の具体的な構成例を示すもの
である。すなわち第４図において、被検査材（シームレ
スパイプ）２６に電極Ｐ １ ＋Ｐ２を介して、交流磁
化電源２７から交流電流を供給する。また、被検査材２
６の中空部内に磁気センサー２８を挿入して、被検査材
２６の中空部内を走行させる。ここで、もし被検査材２
６に欠陥、あるいは機械歪みや熱歪みが存在すると、被
検査材２６の中空部内に交流の漏洩磁束が発生する。こ
の漏洩磁束を、磁気センサー２８で電気信号に変換し、
信号増幅器２９に入力する。そして、この信号増幅器２
９で約１００倍〜１０００倍に増幅した後、同期検波器
３０に入力する。一方、同期検波器３０には交流磁化電
源２７の電圧を、移相器３１を介し基準電圧として入力
している。FIG. 4 shows a specific configuration example when applied to a flaw detection method for seamless pipes used for boiler tubes and the like. That is, in FIG. 4, an alternating current is supplied from an alternating current magnetization power source 27 to a material to be inspected (seamless pipe) 26 via electrodes P 1 +P2. In addition, the material to be inspected 2
The magnetic sensor 28 is inserted into the hollow part of the material 26 to be inspected and is made to travel within the hollow part of the material 26 to be inspected. Here, if the material to be inspected 2
If there is a defect, mechanical strain, or thermal strain in the test material 6 , an alternating current leakage magnetic flux is generated within the hollow portion of the test material 26 . This leakage magnetic flux is converted into an electric signal by the magnetic sensor 28,
The signal is input to the signal amplifier 29. And this signal amplifier 2
After the signal is amplified approximately 100 to 1000 times in step 9, it is input to the synchronous detector 30. On the other hand, the voltage of the AC magnetizing power source 27 is inputted to the synchronous detector 30 as a reference voltage via the phase shifter 31.
そして同期検波器３０で、信号増幅器２９からの出力電
圧と、交流磁化電源２７の基準電圧とを比較することに
よって、同期検波器３０の出力端子には、両信号電圧の
位相差θと、信号増幅器２９の出力電圧ｅｓに対応した
出力（ｅ ｓ ｃｏｓθ）が得られる。従って、移相器
３１の基準電圧の位相をノイズ電圧の位相と９０度差に
調整することによってノイズ電圧が除去されるため、同
期検波器３０の出力電圧を図示しない記録計等で記録す
ることにより、被検査材２６であるシームレスパイプの
欠陥を、高いＳ／Ｎ比で探傷することが可能である。The synchronous detector 30 compares the output voltage from the signal amplifier 29 with the reference voltage of the AC magnetizing power supply 27, and the output terminal of the synchronous detector 30 receives the phase difference θ between the two signal voltages and the signal. An output (es cos θ) corresponding to the output voltage es of the amplifier 29 is obtained. Therefore, since the noise voltage is removed by adjusting the phase of the reference voltage of the phase shifter 31 to be 90 degrees different from the phase of the noise voltage, the output voltage of the synchronous detector 30 can be recorded with a recorder or the like (not shown). This makes it possible to detect defects in the seamless pipe, which is the material to be inspected 26, with a high S/N ratio.
第５図は、シームレスパイプを探傷し、基準電圧（移相
器３１の出力電圧）の位相に対するＳ／Ｎ比をプロット
した特性を示すものである。第５図に示すように、基準
電圧の位相を０度または１８０度に設定すると、Ｓ／Ｎ
比が向上する。因みに、前述した従来の方法による信号
電圧の振幅値でのＳ／Ｎ比は約０．４である。従って、
本磁気探傷法を適用することにより、Ｓ／Ｎ比を約５倍
向上することが実証できた。FIG. 5 shows the characteristics obtained by testing a seamless pipe and plotting the S/N ratio against the phase of the reference voltage (output voltage of the phase shifter 31). As shown in Figure 5, when the phase of the reference voltage is set to 0 degrees or 180 degrees, the S/N
ratio is improved. Incidentally, the S/N ratio in the amplitude value of the signal voltage according to the conventional method described above is about 0.4. Therefore,
By applying this magnetic flaw detection method, we were able to demonstrate that the S/N ratio could be improved by about 5 times.
尚、本発明は上記実施例に限定されるものではなく、次
のようにしても同様に実施することができるものである
。It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be similarly implemented in the following manner.
第６図は、本発明による磁気探傷法を実現するためのそ
の他の構成例を示すものである。第６図において、Ｃ１
，Ｃ２，Ｃ３１Ｃ４は円環状の鉄心に、その円周方向に
４個に分割して夫々巻回されたトロイダルコイルで、こ
れらにより磁気センサーを構成している。また、３２
ａ、 ３２ ｂｒ３２ｃ、３２ｄは各々のトロイダル
コイルＣ１゜ｃ２＋ Ｃ３＋ Ｃ４からの信号電圧を所
期値に増幅する信号増幅器、３３は図示しない交流磁化
電源の電圧を入力とする移相器、３４ａ、３４ｂ。FIG. 6 shows another configuration example for realizing the magnetic flaw detection method according to the present invention. In Figure 6, C1
, C2, C31C4 are toroidal coils that are divided into four pieces and wound around an annular iron core in the circumferential direction, respectively, and constitute a magnetic sensor. Also, 32
a, 32 br32c, 32d are signal amplifiers that amplify the signal voltage from each toroidal coil C1゜c2+C3+C4 to a desired value; 33 is a phase shifter that inputs the voltage of an AC magnetizing power source (not shown); 34a, 34b .
３４ｃ、３４ｄは各々の信号増幅器３２ａ。34c and 34d are respective signal amplifiers 32a.
３２ｂ、３２ｃ、３２ｄからの出力電圧と、移相器３３
からの基準電圧とを比較して移相解析を行なう同期検波
器である。Output voltages from 32b, 32c, 32d and phase shifter 33
This is a synchronous detector that performs phase shift analysis by comparing the reference voltage from the
さて、かかる構成のトロイダルコイル型の磁気センサー
を、前述した第４図の被検査材２６の中空部内に、第７
図（ａ）に示すように挿入して当該中空部内を走行させ
る。ここで、もし被検査材２６に欠陥が存在すると、被
検査材２６の中空部内に円周漏洩磁束が発生するので、
この円周漏洩磁束がトロイダルコイルＣ１，Ｃ２，Ｃ３
，Ｃ４からなる磁気センサーと交叉し、欠陥に近いトロ
イダルコイルにより大振幅の欠陥信号が誘起される。そ
して、当該トロイダルコイルからの欠陥信号が、これに
対応した信号増幅器に人力される。Now, the toroidal coil type magnetic sensor having such a configuration is installed in the hollow part of the inspected material 26 shown in FIG.
It is inserted as shown in Figure (a) and made to travel within the hollow section. Here, if there is a defect in the material to be inspected 26, circumferential leakage magnetic flux will occur within the hollow part of the material to be inspected.
This circumferential leakage magnetic flux is the toroidal coil C1, C2, C3
, C4, and a large-amplitude defect signal is induced by the toroidal coil close to the defect. Then, the defect signal from the toroidal coil is input to a corresponding signal amplifier.
この欠陥信号は信号増幅器で増幅した後、これに対応し
た同期検波器に入力される。一方、この同期検波器には
移相器３３からの基準電圧も入力されている。そして、
当該同期検波器で対応した信号増幅器からの出力電圧と
、移相器３３からの基準電圧とを比較することによって
、同期検波器の出力端子には、両信号電圧の位相差と、
信号増幅器の出力電圧に対応した出力が得られる。This defective signal is amplified by a signal amplifier and then input to a corresponding synchronous detector. On the other hand, the reference voltage from the phase shifter 33 is also input to this synchronous detector. and,
By comparing the output voltage from the signal amplifier corresponding to the synchronous detector with the reference voltage from the phase shifter 33, the output terminal of the synchronous detector receives the phase difference between the two signal voltages,
An output corresponding to the output voltage of the signal amplifier is obtained.
この場合、欠陥と４個のトロイダルコイルＣ１＋Ｃ２ｒ
Ｃ３、Ｃ４との被検査材との円周方向との相対角度
αに対する検出感度は、第７図（ｂ）に示すような特性
となる。従って、被検査材の円周方向のどの部分に欠陥
が存在していても、４個のトロイダルコイルＣＩ ＊
Ｃ２ｒ Ｃ３、Ｃ４の誘起電圧を計測することによ
り、当該部分の欠陥を確実に検出することができる。In this case, the defect and the four toroidal coils C1+C2r
The detection sensitivity with respect to the relative angle α between C3 and C4 and the circumferential direction of the material to be inspected has a characteristic as shown in FIG. 7(b). Therefore, no matter where a defect exists in the circumferential direction of the inspected material, the four toroidal coils CI *
By measuring the induced voltages of C2r, C3, and C4, defects in the relevant portions can be reliably detected.
以上のように本実施例では、前述の実施例と同様に、機
械加工歪みや熱歪みによるノイズ電圧を除去し、Ｓ／Ｎ
比を向上させて極めて高精度に欠陥の探傷を行なうこと
が可能である。また、磁気センサーを、円周方向に４個
に分割されたトロイダルコイルから構成しているので、
被検査材の軸方向への厚みが１〜２ ｍｍと極めて小さ
く、シームレスバイブ等の曲管の探傷への適用も可能で
ある。As described above, in this embodiment, noise voltage due to machining distortion and thermal distortion is removed, and S/N
It is possible to improve the ratio and perform defect detection with extremely high precision. In addition, since the magnetic sensor is composed of a toroidal coil divided into four pieces in the circumferential direction,
The thickness of the material to be inspected in the axial direction is extremely small, 1 to 2 mm, and it can also be applied to flaw detection of curved pipes such as seamless vibes.
さらに、磁気センサーをコイル方式としているので、温
度変化等による出力電圧のドリフトが無く、経時変化特
性が良好でかつ耐久性も優れている。Furthermore, since the magnetic sensor is of a coil type, there is no drift in the output voltage due to temperature changes, etc., and the sensor has good aging characteristics and excellent durability.
（発明の効果）
以上説明したように本発明によれば、被検査材を磁化し
、欠陥部から発生する漏洩磁束を磁気センサーで検知し
て欠陥を検出する場合に、磁化方法として交流磁化を使
用し、磁気センサーからの出力信号を位相解析して欠陥
信号を抽出するようにしたので、機械加工歪みや熱歪み
によるノイズ電圧を除去し極めて高精度の探傷を行なう
ことが可能な磁気探傷法が提供できる。(Effects of the Invention) As explained above, according to the present invention, AC magnetization is used as a magnetization method when a defect is detected by magnetizing a material to be inspected and detecting leakage magnetic flux generated from a defective part with a magnetic sensor. The magnetic flaw detection method enables extremely high-precision flaw detection by eliminating noise voltage caused by machining distortion and thermal distortion. can be provided.
第１図は本発明による磁気探傷法の基本原理を示す構成
図、第２図は第１図における欠陥と局部的な機械歪みに
よるノイズ電圧の位相特性を示す図、第３図は本発明に
よる磁気探傷法を実現するための一実施例を示す構成図
、第４図はシームレスバイブの探傷法に適用した場合の
具体的な構成例を示す図、第５図は第４図における基準
電圧の位相に対するＳ／Ｎ比の特性を示す図、第６図は
本発明による磁気探傷法を実現するための他の実施例を
示す構成図、第７図（ａ）（ｂ）は第６図における磁気
探傷法を夫々説明するための図、第８図は従来の磁気探
傷法の原理を示す概要構成図である。
８・・・電磁石、９・・・電磁石ヨーク、１０・・・被
検査材、１１・・・交流磁化電源、１２・・・磁気セン
サー、１３・・・欠陥部、１４・・・漏洩磁束、１５・
・・機械歪み部、１６・・・信号増幅器、１７・・・信
号電圧ベクトル解析器、１８・・・電磁石、１９・・・
電磁石ヨーク、２０・・・被検査材、２１・・・磁気セ
ンサー、２２・・・信号増幅器、２３・・・同期検波器
、２４・・・交流磁化電源、２５・・・移相器、２６・
・・被検査材（シームレスバイブ） 、Ｐ １＊ Ｐ
２・・・電極、２７・・・交流磁化電源、２８・・・
磁気センサー、２９・・・信号増幅器、３０・・・同期
検波器、３１・・・移相器、Ｃ１＊ ｃ２１ｃ３．Ｃ４
−）−０イダルコイル、３２ ａ、 ３２ ｂ。
３２ｃ、３２ｄ・・・信号増幅器、３３・・・移相器、
３４ａ、３４ｂ、３４ｃ、３４ｄ−・・同期検波器。
出願人代理人 弁理士 鈴江武彦
第３図
♂
冗・ ： 〜
詔択Fig. 1 is a block diagram showing the basic principle of the magnetic flaw detection method according to the present invention, Fig. 2 is a diagram showing the phase characteristics of noise voltage due to defects and local mechanical distortion in Fig. 1, and Fig. 3 is a diagram according to the present invention. A configuration diagram showing an example of implementing the magnetic flaw detection method, FIG. 4 is a diagram showing a specific configuration example when applied to the seamless vibrator flaw detection method, and FIG. 5 is an illustration of the reference voltage in FIG. A diagram showing the characteristics of the S/N ratio with respect to the phase, FIG. 6 is a block diagram showing another embodiment for realizing the magnetic flaw detection method according to the present invention, and FIGS. 7(a) and (b) are the same as in FIG. 6. FIG. 8 is a diagram for explaining the magnetic flaw detection method, and is a schematic configuration diagram showing the principle of the conventional magnetic flaw detection method. 8... Electromagnet, 9... Electromagnetic yoke, 10... Material to be inspected, 11... AC magnetization power supply, 12... Magnetic sensor, 13... Defect part, 14... Leakage magnetic flux, 15.
... Mechanical distortion section, 16... Signal amplifier, 17... Signal voltage vector analyzer, 18... Electromagnet, 19...
Electromagnetic yoke, 20... Material to be inspected, 21... Magnetic sensor, 22... Signal amplifier, 23... Synchronous detector, 24... AC magnetization power supply, 25... Phase shifter, 26・
・・Inspected material (seamless vibe), P 1* P
2... Electrode, 27... AC magnetization power supply, 28...
Magnetic sensor, 29... Signal amplifier, 30... Synchronous detector, 31... Phase shifter, C1* c21c3. C4
-) -0 Idalcoil, 32 a, 32 b. 32c, 32d...signal amplifier, 33...phase shifter,
34a, 34b, 34c, 34d--synchronous detectors. Applicant's agent Patent attorney Takehiko Suzue Figure 3
Claims (4)
を磁気センサーで検知して欠陥を検出する磁気探傷法に
おいて、磁化方法として交流磁化を使用し、磁気センサ
ーからの出力信号を位相解析して欠陥信号を抽出するよ
うにしたことを特徴とする磁気探傷法。(1) In the magnetic flaw detection method, which detects defects by magnetizing the material to be inspected and detecting the leakage magnetic flux generated from the defective part using a magnetic sensor, alternating current magnetization is used as the magnetization method, and the output signal from the magnetic sensor is phased. A magnetic flaw detection method characterized by analyzing and extracting defect signals.
求の範囲第（１）項記載の磁気探傷法。(2) The magnetic flaw detection method according to claim (1), wherein the magnetic sensor is a toroidal coil.
各々のコイルからの出力信号について位相解析して欠陥
信号を抽出するようにした特許請求の範囲第（２）項記
載の磁気探傷法。(3) Divide the toroidal coil into multiple pieces in the circumferential direction,
The magnetic flaw detection method according to claim (2), wherein the defect signal is extracted by phase analysis of the output signal from each coil.
を欠陥信号として取出すようにした特許請求の範囲第（
１）項乃至第（３）項のいずれか１項に記載の磁気探傷
法。(4) The phase analysis method extracts a component orthogonal to the phase of the pseudo signal as a defect signal.
The magnetic flaw detection method according to any one of items 1) to (3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62278667A JP2666301B2 (en) | 1987-11-04 | 1987-11-04 | Magnetic flaw detection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62278667A JP2666301B2 (en) | 1987-11-04 | 1987-11-04 | Magnetic flaw detection |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01119757A true JPH01119757A (en) | 1989-05-11 |
| JP2666301B2 JP2666301B2 (en) | 1997-10-22 |
Family
ID=17600482
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62278667A Expired - Fee Related JP2666301B2 (en) | 1987-11-04 | 1987-11-04 | Magnetic flaw detection |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2666301B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10307124A (en) * | 1997-05-08 | 1998-11-17 | Kajima Corp | Method and device for non-destructive inspection for body steel frame |
| JP2006220526A (en) * | 2005-02-10 | 2006-08-24 | Jfe Steel Kk | Surface layer part property measuring method, surface layer defect determination method using the same, and metallic band manufacturing method |
| JP2007256274A (en) * | 2006-02-24 | 2007-10-04 | Jfe Steel Kk | Method and device for detecting small surface irregularity defect |
| JP2009052997A (en) * | 2007-08-27 | 2009-03-12 | Maeda:Kk | Metal fatigue discrimination device and metal fatigue discrimination method |
| JP2012032249A (en) * | 2010-07-30 | 2012-02-16 | Hitachi-Ge Nuclear Energy Ltd | Eddy current detection method and eddy current detection system |
| JP2018071983A (en) * | 2016-10-24 | 2018-05-10 | 国立大学法人 岡山大学 | Magnetic nondestructive inspection method and magnetic nondestructive inspection device |
| CN115047060A (en) * | 2022-05-23 | 2022-09-13 | 中国矿业大学 | Stripping method for pipeline weld defect magnetic leakage signal |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5437979B2 (en) * | 2010-11-12 | 2014-03-12 | 三菱電機株式会社 | Wire rope flaw detector |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60192252A (en) * | 1984-03-13 | 1985-09-30 | Sumitomo Metal Ind Ltd | Flaw detecting method |
| JPS63221239A (en) * | 1987-03-10 | 1988-09-14 | Sumitomo Metal Ind Ltd | Leak magnetic flux flaw detecting method |
-
1987
- 1987-11-04 JP JP62278667A patent/JP2666301B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60192252A (en) * | 1984-03-13 | 1985-09-30 | Sumitomo Metal Ind Ltd | Flaw detecting method |
| JPS63221239A (en) * | 1987-03-10 | 1988-09-14 | Sumitomo Metal Ind Ltd | Leak magnetic flux flaw detecting method |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10307124A (en) * | 1997-05-08 | 1998-11-17 | Kajima Corp | Method and device for non-destructive inspection for body steel frame |
| JP2006220526A (en) * | 2005-02-10 | 2006-08-24 | Jfe Steel Kk | Surface layer part property measuring method, surface layer defect determination method using the same, and metallic band manufacturing method |
| JP4586556B2 (en) * | 2005-02-10 | 2010-11-24 | Ｊｆｅスチール株式会社 | Surface layer property measurement method, surface layer defect determination method using the same, and metal strip manufacturing method |
| JP2007256274A (en) * | 2006-02-24 | 2007-10-04 | Jfe Steel Kk | Method and device for detecting small surface irregularity defect |
| JP2009052997A (en) * | 2007-08-27 | 2009-03-12 | Maeda:Kk | Metal fatigue discrimination device and metal fatigue discrimination method |
| JP2012032249A (en) * | 2010-07-30 | 2012-02-16 | Hitachi-Ge Nuclear Energy Ltd | Eddy current detection method and eddy current detection system |
| JP2018071983A (en) * | 2016-10-24 | 2018-05-10 | 国立大学法人 岡山大学 | Magnetic nondestructive inspection method and magnetic nondestructive inspection device |
| CN115047060A (en) * | 2022-05-23 | 2022-09-13 | 中国矿业大学 | Stripping method for pipeline weld defect magnetic leakage signal |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2666301B2 (en) | 1997-10-22 |
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