JP2855186B2 - Non-destructive measurement method of surface flaw by multi-frequency magnetization - Google Patents
Non-destructive measurement method of surface flaw by multi-frequency magnetizationInfo
- Publication number
- JP2855186B2 JP2855186B2 JP6659196A JP6659196A JP2855186B2 JP 2855186 B2 JP2855186 B2 JP 2855186B2 JP 6659196 A JP6659196 A JP 6659196A JP 6659196 A JP6659196 A JP 6659196A JP 2855186 B2 JP2855186 B2 JP 2855186B2
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- flaw
- frequencies
- magnetization
- present
- 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 - Lifetime
Links
Landscapes
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、複数周波数磁化
による表面傷の非破壊計測方法に関するものである。さ
らに詳しくは、この発明は、鋼、鉄等の強磁性材料の表
面の傷を迅速、かつ、高精度に測定することのできる複
数周波数磁化による表面傷の非破壊計測方法に関するも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for non-destructively measuring surface flaws caused by multiple frequency magnetization. More specifically, the present invention relates to a non-destructive method for measuring surface flaws by multi-frequency magnetization, which can quickly and accurately measure flaws on the surface of ferromagnetic materials such as steel and iron.
【０００２】[0002]
【従来の技術とその課題】鋼、鉄等の金属材料において
は、管状、棒状、板状等の加工品の製造ライン等でその
表面に存在する傷を正確に検出し、その大きさを高精度
で迅速に計測することは、材料の品質と信頼性向上にと
って極めて重要である。従来より、このような材料表面
の傷の検出のための方法として漏洩磁束探傷法がその代
表例として知られており、この方法では、直流または単
一周波数による交流により、強磁性金属材料を磁化さ
せ、その表面に存在する傷によって生じる漏洩磁束を磁
気センサー等によって検知し、その信号出力から傷の大
きさを測定している。2. Description of the Related Art In the case of metal materials such as steel and iron, a flaw existing on the surface of a tubular, rod-like, plate-like, or other processed product is accurately detected and its size is increased. Quick and accurate measurement is extremely important for improving material quality and reliability. Conventionally, as a method for detecting such a flaw on a material surface, a magnetic flux leakage inspection method is known as a typical example. In this method, a ferromagnetic metal material is magnetized by a direct current or an alternating current of a single frequency. Then, the magnetic flux leaked due to the scratches present on the surface is detected by a magnetic sensor or the like, and the size of the scratches is measured from the signal output.
【０００３】しかしながら、この従来の漏洩磁束探傷法
では、検出した信号出力の振幅から材料表面の傷の評価
を行っていることから、計測途中であっても数時間おき
に計測装置における増幅率を確認し、その増幅率が時間
とともに許容範囲以上に変化していないことを確かめた
上で、探傷を継続しなければならないという問題があっ
た。However, in this conventional magnetic flux leakage inspection method, since the flaw on the material surface is evaluated from the amplitude of the detected signal output, the amplification factor in the measuring device is changed every few hours even during the measurement. After confirming and confirming that the amplification factor did not change beyond the allowable range with time, there was a problem that the flaw detection had to be continued.
【０００４】また、日本工業規格（ＪＩＳ Ｚ ３２１
９）において規定されているように、鋼材料の表面傷を
検知する場合には、漏洩磁束探傷計測装置の安定性を確
認するために、あえて対比試験片を用いて適時それらの
信号出力を確認し、漏洩磁束探傷計測装置が正しく作動
しているかどうか確かめることが義務づけられている。In addition, Japanese Industrial Standards (JIS Z 321)
As specified in 9), when detecting surface flaws on steel materials, the signal output of these devices is timely checked using a comparative test piece in order to check the stability of the magnetic flux leakage measuring device. However, it is mandatory to check whether the leakage magnetic flux detection measuring device is operating properly.
【０００５】このように従来の漏洩磁束探傷法において
は、計測装置の増幅率が時間とともに変動するためその
影響を避けることができず、計測装置の増幅率の確認の
ために製造ラインを止めなければならないため、製造ラ
インの作業効率の向上にとって大きな制約となってい
た。この発明は、以上の通りの事情に鑑みてなされたも
のであり、従来の材料表面傷の計測法の欠点を解消し、
計測装置の増幅率の確認作業を省略することができ、し
かも材料表面の傷を迅速、かつ精度良く測定することが
できる新しい材料表面傷の非破壊計測方法を提供するこ
とを目的としている。As described above, in the conventional magnetic flux leakage inspection method, since the amplification factor of the measuring device fluctuates with time, the influence cannot be avoided, and the production line must be stopped to check the amplification factor of the measuring device. This has been a major constraint on improving the efficiency of the production line. The present invention has been made in view of the above circumstances, and eliminates the drawbacks of the conventional method of measuring a material surface flaw,
An object of the present invention is to provide a new non-destructive method for measuring material surface flaws, which can omit the operation of checking the amplification factor of a measuring device and can quickly and accurately measure flaws on a material surface.
【０００６】[0006]
【課題を解決するための手段】この発明は、上記の課題
を解決するために、複数の周波数による交流磁界を用い
て材料の表面に沿う方向の水平磁界を作用させて材料を
磁化させ、材料表面に存在する傷によって生じる漏洩磁
束を検知し、信号出力を複数の周波数成分に分離して信
号の出力比を求めて傷を評価することを特徴とする複数
周波数磁化による表面傷の非破壊計測方法を提供する。According to the present invention, in order to solve the above-mentioned problems, a horizontal magnetic field in a direction along a surface of a material is applied by using an alternating magnetic field having a plurality of frequencies to change the material. Surface flaws due to multi-frequency magnetization characterized by magnetizing, detecting leakage magnetic flux caused by flaws present on the material surface, separating the signal output into a plurality of frequency components, determining the signal output ratio and evaluating the flaws To provide a non-destructive measurement method.
【０００７】[0007]
【発明の実施の形態】従来の漏洩磁束探傷法が、直流ま
たは単一周波数による交流磁化を用いていたこととは異
って、この発明の方法においては、上記のとおり、複数
の周波数による交流磁界を用いて金属材料の表面に沿う
方向の水平磁界を作用させて材料を磁化させる。すなわ
ち、たとえば図１に示したように、材料表面（１０）に
存在する傷（１１）を、材料の表面に沿う長手方向の水
平磁界の印加により発生する漏洩磁束（１２）の磁気セ
ンサ（１３）等による検知として確認し、その検知信号
を複数の磁化周波数に同期する信号成分にそれぞれ分離
して、各信号の出力比から傷を評価する。DETAILED DESCRIPTION OF THE INVENTION Conventional leakage flux flaw detection method, different to what has been using alternating current magnetization by the DC or single frequency
What, in the method of the present invention, as described above, along the surface of the metal material using an alternating magnetic field by a plurality of frequencies
By acting direction of the horizontal magnetic field Ru magnetizes the material. Sand
That is, as shown in FIG. 1 , for example, a scratch (11) present on the material surface (10) is removed by a longitudinal water along the surface of the material.
The leakage magnetic flux (12) generated by the application of the flat magnetic field is confirmed as detection by the magnetic sensor (13) or the like, and the detection signal is separated into signal components synchronized with a plurality of magnetization frequencies, and the output ratio of each signal is determined. Evaluate the wound.
【０００８】複数周波数の信号成分による出力比を取る
場合には、計測装置の増幅率が変動しても、同一の傷で
あれば常に一定の信号出力比が得られるため、従来法の
ように、計測の途中で増幅率変動の確認を行う必要が一
切なく、効率的に精度の良い探傷が可能となる。このよ
うな優れた特徴のあるこの発明の方法では、たとえば、
図２に示した装置の構成がひとつの態様として採用され
る。When an output ratio based on signal components of a plurality of frequencies is obtained, a constant signal output ratio is always obtained with the same flaw even if the amplification factor of the measuring device fluctuates. In addition, there is no need to confirm the fluctuation of the amplification factor during the measurement, and flaw detection can be performed efficiently and accurately. In the method of the present invention having such excellent characteristics, for example,
The configuration of the device shown in FIG. 2 is adopted as one embodiment.
【０００９】すなわち、この装置は、磁化回路と信号検
出回路とで構成することができ、磁化回路は、適用する
磁化周波数を発振する発振器（１）、複数の発振周波数
出力を混合するミキサ（２）、そのミキサ（２）の出力
を増幅して磁化電流を供給する電力増幅器（３）と、磁
化器（４）を備えている。また検出回路は、材料（５）
からの漏洩磁束を検出する磁気センサ等の磁電素子
（６）と、磁電素子（６）からの信号出力を磁化周波数
に同期した信号成分に分離・増幅させるためのロックイ
ンアンプ（７）、そして得られた信号出力を信号処理す
るための計算機（８）およびその周辺機器（９）を備え
ている。That is, this device can be composed of a magnetizing circuit and a signal detecting circuit, and the magnetizing circuit includes an oscillator (1) for oscillating an applied magnetizing frequency and a mixer (2) for mixing a plurality of oscillating frequency outputs. ), A power amplifier (3) for amplifying the output of the mixer (2) and supplying a magnetizing current, and a magnetizer (4). The detection circuit is made of a material (5)
Element (6) such as a magnetic sensor for detecting magnetic flux leakage from the magnetic field, a lock-in amplifier (7) for separating and amplifying a signal output from the magnetoelectric element (6) into a signal component synchronized with a magnetization frequency, and A computer (8) for processing the obtained signal output and a peripheral device (9) are provided.
【００１０】なお、たとえば以上の装置を用いるこの発
明の方法では、複数の周波数による水平磁界で材料を磁
化し、それぞれの周波数による信号成分の比を取って材
料表面に存在する傷を評価するため、その適用周波数の
差が小さいと出力の差も小さくなり、傷の大きさに対す
る出力比の変化の勾配が小さくなる。つまり、磁化周波
数の差が小さいと、傷寸法の評価精度が低下する傾向に
ある。In the method of the present invention using the above-described apparatus, for example, the material is magnetized by a horizontal magnetic field at a plurality of frequencies, and the ratio of signal components at each frequency is taken to evaluate the flaw present on the material surface. When the difference between the applied frequencies is small, the difference in output is also small, and the gradient of the change in the output ratio with respect to the size of the flaw is small. That is, when the difference between the magnetization frequencies is small, the evaluation accuracy of the flaw size tends to decrease.
【００１１】このため、この発明の方法においては、適
用周波数の差はある程度大きい方が傷寸法の評価に効果
的であり、たとえば、その２つの周波数の差はおよそ１
０倍程度が望ましい。またその適用周波数については、
最低でも２種類の周波数が必要であり、もちろん、さら
に多種類の周波数を用いることもできる。Therefore, in the method of the present invention, it is more effective to evaluate the flaw size if the difference between the applied frequencies is somewhat large. For example, the difference between the two frequencies is about 1
About 0 times is desirable. For the applicable frequency,
At least two types of frequencies are required, and of course, more types of frequencies can be used.
【００１２】さらにこの発明の方法の実施に際しては、
材料表面の傷が、その長手方向と磁化方向とで角度をも
って、つまり交差角度をもって存在する場合が多い。す
なわち、図１に示したように、漏洩磁束探傷では通常は
法線成分（Ｂｚ）または接線成分（Ｂｘ）を測定する。
しかし、図３の模式平面図に示したように、傷の長さ方
向と磁化方向とが交差して交差角度（θｃ）を持つこと
が多い。このような場合には、この交差角度（θｃ）の
大きさそのものを評価することや、この交差角度（θ
ｃ）の影響を考慮することが必要となる。Further, in carrying out the method of the present invention,
In many cases, flaws on the material surface exist at an angle between the longitudinal direction and the magnetization direction, that is, at an intersection angle. That is, as shown in FIG. 1, normally, the normal component (Bz) or the tangential component (Bx) is measured in the magnetic flux leakage inspection.
However, as shown in the schematic plan view of FIG. 3 , the length direction of the flaw and the magnetization direction intersect and often have an intersection angle (θc). In such a case, the magnitude of the intersection angle (θc) itself is evaluated, or the intersection angle (θc) is evaluated.
It is necessary to consider the effect of c).
【００１３】磁束の測定成分を接線成分（Ｂｘ）とする
と、この接線成分（Ｂｘ）の分解成分は、図３のように
傷端面に直交する成分（Ｂｘｒ）、磁化方向に直角な成
分（Ｂｘｘ）と磁化方向に平行な成分（Ｂｘｙ）とな
り、交差角度（θｃ）が図３（ｂ）のように９０°の場
合、漏洩磁束は最大値Ｂｘｍとなる。そしてＢｘｘ＝０
である。Assuming that the measured component of the magnetic flux is a tangential component (Bx), a decomposition component of the tangential component (Bx) is a component (Bxxr) orthogonal to the wound end face and a component (Bxx) perpendicular to the magnetization direction as shown in FIG. ) And a component (Bxy) parallel to the magnetization direction, and when the intersection angle (θc) is 90 ° as shown in FIG. 3B, the leakage flux has a maximum value Bxm. And Bxx = 0
It is.
【００１４】また、ＢｘｘとＢｘｙを検出することによ
り、交差角度θｃが求められる。なお、図４に例示した
ように、ホール素子を用い、これを直交配置させたセン
サを構成し、一つの素子面が磁化方向を向くように置い
て、このセンサを磁化方向に平行に走査すると、Ｂｘ
ｘ、Ｂｘｙが同時に得られる。以上のことを考慮して、
この発明の方法はより具体的に適用されることになる。Further, by detecting Bxx and Bxy, the intersection angle θc is obtained. As illustrated in FIG. 4, a sensor in which Hall elements are used and arranged orthogonal to each other is configured, and one element surface is placed so as to face the magnetization direction, and this sensor is scanned in parallel to the magnetization direction. , Bx
x and Bxy are obtained at the same time. With the above in mind,
The method of the present invention will be more specifically applied.
【００１５】以下実施例を示し、さらに詳しくこの発明
の実施の形態について説明する。もちろん、この発明
は、以下の実施例によって何ら限定されるものではな
い。Hereinafter, examples will be shown, and embodiments of the present invention will be described in more detail. Of course, this invention is not limited at all by the following Examples.
【００１６】[0016]
【実施例】長さ２２０ｍｍ×幅５０ｍｍ×高さ１０ｍｍ
のＳＭ５０Ａ鋼の表面にワイヤカットにより長さ５０ｍ
ｍ、幅０．２９ｍｍ、深さ各々０．２１ｍｍ，０．３５
ｍｍ，０．９５ｍｍ，１．８ｍｍの人工溝を加工して試
料とした。図２に例示した装置を用い、２台の発振器
（１）の周波数をそれぞれｆ1 ＝０．１ｋＨｚとｆ2 ＝
１．０ｋＨｚとした。さらに比較のために、ｆ2 ＝１．
０ｋＨｚのままで、ｆ1 ＝０．２ｋＨｚとｆ1 ＝０．５
ｋＨｚの場合についても試験を行った。[Example] Length 220 mm x width 50 mm x height 10 mm
50m length by wire cutting on the surface of SM50A steel
m, width 0.29mm, depth 0.21mm, 0.35 each
mm, 0.95 mm and 1.8 mm artificial grooves were machined to obtain samples. Using the apparatus illustrated in FIG. 2, the frequencies of the two oscillators (1) are set to f 1 = 0.1 kHz and f 2 =
1.0 kHz. For further comparison, f 2 = 1.
It remains 0kHz, f 1 = 0.2kHz and f 1 = 0.5
The test was also performed for the case of kHz.
【００１７】発振器（１）の出力はミキサ（２）で混合
した後、電力増幅して磁化器（４）に供給した。磁電素
子としてコイルを用い、漏洩磁束によるコイル信号出力
は、２台のロックインアンプ（７）に入力し、各発振周
波数に同期した信号成分は、各々のロックインアンプ
（７）より取り出し、データを計算機（８）に入力し
た。The output of the oscillator (1) was mixed in the mixer (2), and then power-amplified and supplied to the magnetizer (4). Using a coil as a magneto-electric element, a coil signal output due to a leakage magnetic flux is input to two lock-in amplifiers (7), and a signal component synchronized with each oscillation frequency is taken out from each lock-in amplifier (7). Was input to the calculator (8).
【００１８】計算機（８）に取り込まれた２つの周波数
の信号成分に対して、計算機内部で次の処理を行なっ
た。まず、各同期周波数に対応する材料表面磁界を用い
て、それぞれの周波数に対応する信号成分を基準化し、
次に２つの磁化周波数のうち高い方の周波数による傷信
号出力値に対する比（Ａf1／Ａf2）を算出した。The following processing was performed inside the computer for the signal components of the two frequencies taken into the computer (8). First, using the material surface magnetic field corresponding to each synchronization frequency, standardize the signal components corresponding to each frequency,
Next, the ratio (A f1 / A f2 ) to the flaw signal output value at the higher frequency of the two magnetization frequencies was calculated.
【００１９】以上の方法により、交差角度（θｃ）＝９
０°の場合の、ｆ2 ＝１．０ｋＨｚに対するｆ1 ＝０．
１ｋＨｚ，０．２ｋＨｚ，０．５ｋＨｚの場合の、傷深
さと各ピーク・ピーク出力比との関係を求めた。その結
果を示したものが図５である。この図５を較正曲線とし
て、未知の傷深さを求めることができる。このとき、ｆ
1 ＝０．１ｋＨｚの方が、ｆ1 ＝０．２ｋＨｚ，０．５
ｋＨｚの場合よりも、曲線の勾配が急であり、ｆ1 ＝
０．１ｋＨｚを用いた方が、高精度な計測が可能である
ことが確認された。According to the above method, the intersection angle (θc) = 9
In the case of 0 °, f 1 = 0.0 for f 2 = 1.0 kHz.
The relationship between the flaw depth and each peak-to-peak output ratio at 1 kHz, 0.2 kHz, and 0.5 kHz was determined. FIG. 5 shows the result. Using this FIG. 5 as a calibration curve, the unknown flaw depth can be determined. At this time, f
1 = 0.1 kHz, f 1 = 0.2 kHz, 0.5
The slope of the curve is steeper than in the case of kHz, and f 1 =
It was confirmed that the use of 0.1 kHz enables more accurate measurement.
【００２０】ここで計測装置の増幅率が変化した場合で
も、Ａf1とＡf2はともに比例的に変化するため、これら
の比は増幅率の変動に影響されず常に安定な値を示す。
各周波数における出力比から傷深さを高精度に評価する
ことができる。Here, even when the amplification factor of the measuring device changes, both A f1 and A f2 change proportionally, and therefore these ratios always show a stable value without being affected by the fluctuation of the amplification factor.
The flaw depth can be evaluated with high accuracy from the output ratio at each frequency.
【００２１】[0021]
【発明の効果】以上詳しく説明したように、この発明に
おいては、複数の周波数による交流磁界を用いて金属材
料の表面に沿う方向の水平磁界を作用させて材料を磁化
させ、それを複数の磁化周波数に同期する信号成分にそ
れぞれ分離して、各信号の出力比を取って傷を評価する
ので、計測装置の増幅率が変動しても、常に一定の信号
出力比が得られ、計測の途中で増幅率変動の確認を行う
必要が一切なく、迅速で高精度な探傷が可能となる。As described in detail above, in the present invention, a horizontal magnetic field in the direction along the surface of a metal material is actuated using an alternating magnetic field at a plurality of frequencies to magnetize the material , which is then magnetized by a plurality of magnets. Each component is separated into frequency-synchronized signal components, and the flaw is evaluated by taking the output ratio of each signal.Thus, even if the amplification factor of the measuring device fluctuates, a constant signal output ratio is always obtained, and during the measurement, There is no need to confirm the change in the amplification factor at all, and quick and highly accurate flaw detection can be performed.
【図１】この発明の方法の原理を示した模式図である。FIG. 1 is a schematic view showing the principle of the method of the present invention.
【図２】この発明を実現するための計測装置の構成を例
示したブロック図である。FIG. 2 is a block diagram illustrating a configuration of a measuring device for realizing the present invention.
【図３】（ａ）（ｂ）は、交差角度（θｃ）と磁束成分
との関係を示した模式平面図である。FIGS. 3A and 3B are schematic plan views showing a relationship between an intersection angle (θc) and a magnetic flux component.
【図４】直交するホール素子を磁気センサとした場合を
例示した模式斜視図である。FIG. 4 is a schematic perspective view illustrating a case where a perpendicular Hall element is a magnetic sensor.
【図５】この発明の実施例として、傷深さとピーク・ピ
ーク出力比との関係を示した図である。FIG. 5 is a diagram showing a relationship between a flaw depth and a peak-to-peak output ratio as an embodiment of the present invention.
１ 発振器 ２ ミキサ ３ 電力増幅器 ４ 磁化器 ５ 金属材料 ６ 磁電素子 ７ ロックインアンプ ８ 計算機 ９ 周辺機器 １０ 金属材料表面 １１ 傷 １２ 漏洩磁束 １３ 磁気センサ DESCRIPTION OF SYMBOLS 1 Oscillator 2 Mixer 3 Power amplifier 4 Magnetizer 5 Metal material 6 Magnetoelectric element 7 Lock-in amplifier 8 Computer 9 Peripheral equipment 10 Metal material surface 11 Scratches 12 Leakage magnetic flux 13 Magnetic sensor
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) G01N 27/72 - 27/90──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 6 , DB name) G01N 27/72-27/90
Claims (1)
料の表面に沿う方向の水平磁界を作用させて材料を磁化
させ、材料表面に存在する傷によって生じる漏洩磁束を
検知し、信号出力を複数の周波数成分に分離してその出
力比を求めて傷を評価することを特徴とする複数周波数
磁化による表面傷の非破壊計測方法。An AC magnetic field having a plurality of frequencies is used to apply a horizontal magnetic field in a direction along a surface of a material to magnetize the material, to detect a leakage magnetic flux caused by a flaw present on the material surface, and to output a plurality of signal outputs. A non-destructive measurement method for surface flaws by multi-frequency magnetization, wherein the flaws are evaluated by obtaining an output ratio of the frequency components.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6659196A JP2855186B2 (en) | 1996-03-22 | 1996-03-22 | Non-destructive measurement method of surface flaw by multi-frequency magnetization |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6659196A JP2855186B2 (en) | 1996-03-22 | 1996-03-22 | Non-destructive measurement method of surface flaw by multi-frequency magnetization |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09257753A JPH09257753A (en) | 1997-10-03 |
| JP2855186B2 true JP2855186B2 (en) | 1999-02-10 |
Family
ID=13320338
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6659196A Expired - Lifetime JP2855186B2 (en) | 1996-03-22 | 1996-03-22 | Non-destructive measurement method of surface flaw by multi-frequency magnetization |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2855186B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4568128B2 (en) * | 2005-01-28 | 2010-10-27 | 新日本製鐵株式会社 | Steel plate butt weld inspection device and inspection method using this device |
| CN108982652B (en) * | 2018-08-15 | 2022-05-20 | 东北大学 | Method for electromagnetic nondestructive detection of metal surface cracks through multi-frequency excitation field array |
-
1996
- 1996-03-22 JP JP6659196A patent/JP2855186B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09257753A (en) | 1997-10-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4107605A (en) | Eddy current flaw detector utilizing plural sets of four planar coils, with the plural sets disposed in a common bridge | |
| WO2010050155A1 (en) | Barkhausen noise inspection apparatus and inspection method | |
| JP4804006B2 (en) | Flaw detection probe and flaw detection apparatus | |
| US3582772A (en) | Method of calibrating eddy current flaw detection equipment utilizing attachable slugs to simulate flaws | |
| JP2841153B2 (en) | Weak magnetism measurement method and device, and nondestructive inspection method using the same | |
| JP2855186B2 (en) | Non-destructive measurement method of surface flaw by multi-frequency magnetization | |
| JPS58218644A (en) | Method and apparatus for testing surface flaw of metallic material | |
| US3588683A (en) | Method and apparatus for nondestructive testing of ferromagnetic articles,to determine the location,orientation and depth of defects in such articles utilizing the barkhausen effect | |
| KR101999945B1 (en) | Apparatus For Measuring Stess of ferromagnetic substance | |
| CA1156311A (en) | Sorting device for tubular goods | |
| JPH07128295A (en) | Method for measuring crystal grain size of steel plate | |
| RU2493561C1 (en) | Eddy current magnetic method of failure detection of ferrous objects | |
| JPS62273447A (en) | Method and apparatus for measuring deterioration degree of material | |
| JPH0628690Y2 (en) | Metal plate defect detector | |
| JPH0612358B2 (en) | Nondestructive measurement method for surface defects | |
| EP0650028A2 (en) | Method and apparatus for measurement of thickness of specimens | |
| JP4349012B2 (en) | Magnetic flaw detection method for ferromagnetic materials | |
| JPH08145952A (en) | Magnetic leakage flux testing method | |
| CN113608154B (en) | In-situ magnetic permeability detection probe, equipment and detection method | |
| JP2001059836A (en) | Method and apparatus for eddy-current flaw detection | |
| JP2010243175A (en) | Barkhausen noise inspecting device | |
| JP6624099B2 (en) | Magnetic measuring method and magnetic measuring device | |
| JPH0439031B2 (en) | ||
| RU2034235C1 (en) | Method for m depth of flaw in ferromagnetic object and device for implementation of said method | |
| JPH03135780A (en) | Method and device for magnetism measurement |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| EXPY | Cancellation because of completion of term |