JP2697467B2 - Leakage magnetic flux detection method - Google Patents
Leakage magnetic flux detection methodInfo
- Publication number
- JP2697467B2 JP2697467B2 JP7514792A JP7514792A JP2697467B2 JP 2697467 B2 JP2697467 B2 JP 2697467B2 JP 7514792 A JP7514792 A JP 7514792A JP 7514792 A JP7514792 A JP 7514792A JP 2697467 B2 JP2697467 B2 JP 2697467B2
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- JP
- Japan
- Prior art keywords
- defect
- magnetic flux
- detected
- phase angle
- steel material
- 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
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【産業上の利用分野】本発明は鋼材欠陥を検出する漏洩
磁束探傷法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic flux leakage detection method for detecting a defect in a steel material.
【０００２】[0002]
【従来の技術】一般的に、鋼材の表面欠陥検出には、表
面肌の影響を受けにくい漏洩磁束探傷法が広く利用され
ている。鋼材を磁化した場合、鋼材にワレ欠陥がある部
分、または局部的な組織変化がある部分では、透磁率が
異なり漏洩磁場が発生する。局部的な組織変化中でも、
特に炭素含有量が多い鋼材では表層部に局部的に発生す
る脱炭部があり、脱炭部はワレ欠陥発生の原因となるこ
とが多い。漏洩磁束探傷法は透磁率の違いを利用し、発
生した漏洩磁場を電磁変換素子を備えたセンサによって
電気信号として検出する方法である。2. Description of the Related Art Generally, a magnetic flux leakage inspection method, which is hardly affected by surface skin, is widely used for detecting a surface defect of a steel material. When a steel material is magnetized, a portion having a crack in the steel material or a portion having a local structural change has a different magnetic permeability and generates a leakage magnetic field. Even during a local organizational change,
Particularly, in a steel material having a high carbon content, there is a decarburized portion locally generated in the surface layer, and the decarburized portion often causes cracking defects. The leakage magnetic flux detection method is a method of detecting a generated leakage magnetic field as an electric signal using a sensor having an electromagnetic conversion element by utilizing a difference in magnetic permeability.
【０００３】図４は鋼材表面にその表面と平行な磁場を
印加したときの漏洩磁束分布図である。図４(a) は、欠
陥による磁束変化を示し、磁束が欠陥部分で鋼材の外側
に洩れ、盛り上がった磁束分布となっている。図４(b)
は、局部的脱炭部による磁束変化を示し、磁束が図４
(a) とは逆に脱炭部で鋼材の内側に入り込むような磁束
分布となっている。FIG. 4 is a leakage magnetic flux distribution diagram when a magnetic field parallel to the surface of a steel material is applied. FIG. 4 (a) shows a change in magnetic flux due to a defect. The magnetic flux leaks out of the steel material at the defective portion, resulting in a raised magnetic flux distribution. Fig. 4 (b)
Fig. 4 shows the change in magnetic flux due to the local decarburization section.
Contrary to (a), the magnetic flux distribution is such that it enters the inside of the steel material at the decarburized part.
【０００４】図５は図４の磁束分布において漏洩磁束の
鋼材表面に対して垂直な方向の成分(以下垂直成分とい
う) をセンサ出力の電気信号の大きさとして表したもの
である。図５(a) は欠陥による漏洩磁束のセンサによっ
て検出された垂直成分分布であり、欠陥中央部の一方側
で磁力線の傾きが最大となる所の垂直成分がプラスピー
クとなる。中央部に達すると傾きがゼロとなり、中央部
に対して他方側で傾きが逆になり、逆方向で最大となる
所の垂直成分がマイナスピークとなる。FIG. 5 shows the component of the leakage magnetic flux in the direction perpendicular to the steel surface (hereinafter referred to as the vertical component) in the magnetic flux distribution of FIG. 4 as the magnitude of the electric signal output from the sensor. FIG. 5A is a vertical component distribution detected by the sensor of the magnetic flux leakage due to the defect, and the vertical component where the gradient of the line of magnetic force is maximum on one side of the defect center has a positive peak. When the central part is reached, the inclination becomes zero, the inclination is reversed on the other side with respect to the central part, and the vertical component at the maximum in the opposite direction becomes a negative peak.
【０００５】図５(b) は局部的脱炭部による漏洩磁場の
センサによって検出された垂直成分分布であり、欠陥に
よる場合とは逆の分布となっている。図６(a),(b) はこ
の欠陥と局部的脱炭部とが同じ場所に重なって存在した
場合の漏洩磁束分布(a) とその磁場のセンサによって検
出された垂直成分分布(b) とを示している。脱炭部に欠
陥がある場合、欠陥の漏洩磁束分布と、その欠陥付近の
脱炭部の漏洩磁束分布とが干渉して、緩やかな漏洩磁束
の垂直成分分布となる。よって、漏洩磁場の検出によっ
て欠陥探傷を行う漏洩磁束探傷法では、脱炭部内欠陥の
検出は不可能とされていた。しかし、高炭素鋼において
前述したようにワレ欠陥の原因となりやすい多数の局部
的脱炭部が鋼材に存在する。FIG. 5 (b) shows a vertical component distribution detected by a sensor of a leakage magnetic field due to a local decarburization portion, and the distribution is reverse to that of a defect. 6 (a) and 6 (b) show the leakage magnetic flux distribution (a) and the vertical component distribution (b) detected by a sensor of the magnetic field when this defect and the local decarburized portion overlap at the same place. Are shown. When there is a defect in the decarburized portion, the leakage magnetic flux distribution of the defect and the leakage magnetic flux distribution of the decarburized portion near the defect interfere with each other to form a gentle vertical component of the leakage magnetic flux. Therefore, it has been considered impossible to detect a defect in a decarburized portion by the leakage magnetic flux inspection method in which defect inspection is performed by detecting a leakage magnetic field. However, as described above, in a high carbon steel, there are a large number of local decarburized portions that are likely to cause cracking defects in the steel material.
【０００６】この問題の解決策としてその鋼材表面に対
して平行方向の磁場と鋼材表面に対して垂直方向の磁場
とを印加し、それぞれ印加した場合に発生する漏洩磁束
分布を鋼材表面に垂直な成分と鋼材表面に平行な成分と
に分離し、センサ検出の２種の信号振幅比を求めること
によってS/N 比を上げて欠陥検出の能力を上げる提案が
ある（特開昭63-221239 号) 。As a solution to this problem, a magnetic field in a direction parallel to the surface of the steel material and a magnetic field in a direction perpendicular to the surface of the steel material are applied. There is a proposal to increase the S / N ratio by separating the component and the component parallel to the steel material surface and determine the two signal amplitude ratios of the sensor detection to improve the capability of defect detection (JP-A-63-221239). ).
【０００７】[0007]
【発明が解決しようとする課題】前述した提案により脱
炭部内欠陥を探傷することが可能となった。しかし、こ
の方法では水平磁場印加装置と垂直磁場印加装置とを必
要とし、装置として大がかりなものとなりコストも高く
なる。本発明はかかる事情に鑑みてなされたものであ
り、上記のような２つの磁場印加装置を必要とせず、セ
ンサ検出信号の処理方法を変化させることで脱炭部内欠
陥の検出を可能とした漏洩磁束探傷法を提供することを
目的とする。SUMMARY OF THE INVENTION The above-mentioned proposal makes it possible to detect a defect in a decarburized portion. However, in this method, a horizontal magnetic field applying device and a vertical magnetic field applying device are required, so that the device becomes large and the cost increases. The present invention has been made in view of the above circumstances, and does not require the two magnetic field applying devices as described above, and is capable of detecting a defect in a decarburized portion by changing a processing method of a sensor detection signal. An object of the present invention is to provide a magnetic flux inspection method.
【０００８】[0008]
【課題を解決するための手段】本発明に係る漏洩磁束探
傷法は、鋼材表層部を表面と平行な方向に磁化し、表面
近傍に生じた漏洩磁場の鋼材表面に垂直な方向の成分を
磁場検出センサにより電気信号として検出し、検出した
電気信号を同期検波器によって検波し、該鋼材の表面欠
陥を検出する漏洩磁束探傷法において、探傷対象鋼材と
同材質からなり、脱炭部に人工欠陥を有する試料に対し
てその表層部を表面と平行な方向に磁化し、人工欠陥で
の漏洩磁束の表面に垂直な方向の成分を磁場検出センサ
により電気信号として検出し、検出した電気信号を同期
検波して出力レベルが最大となる位相角を検出してお
き、探傷対象鋼材について得た電気信号を検波する際の
位相角を試材について求めた位相角に設定することを特
徴とする。According to the leakage magnetic flux detection method of the present invention, a surface layer of a steel material is magnetized in a direction parallel to the surface, and a component of a leakage magnetic field generated in the vicinity of the surface in a direction perpendicular to the surface of the steel material is used as a magnetic field. Detected as an electric signal by a detection sensor, the detected electric signal is detected by a synchronous detector, and in the magnetic flux leakage detection method for detecting a surface defect of the steel material, a steel material to be inspected is detected.
For samples made of the same material and having artificial defects in the decarburized area
Magnetize the surface layer in a direction parallel to the surface,
Sensor that detects the component of the magnetic flux leakage in the direction perpendicular to the surface
As an electrical signal and synchronize the detected electrical signal
Detect and detect the phase angle at which the output level is maximum.
In this case, the phase angle at the time of detecting the electric signal obtained for the flaw detection target steel material is set to the phase angle obtained for the test material .
【０００９】[0009]
【作用】本発明の漏洩磁束探傷法では、予め検査対象と
同じ材質で局部的脱炭部及び脱炭部内欠陥を人工的に作
成しておいた鋼材に磁場をかけて磁化させ、発生した漏
洩磁場の検出をセンサによって行う。検出した電気信号
の検波を同期検波器で行い、このとき移相器の調節によ
って検波位相を種々に変化させ、位相の相違による出力
信号レベルの相違を調べ、脱炭部内欠陥の出力信号レベ
ルが最大となる位相角を見つけだす。見つけだした位相
角に移相器を使用して設定した上で、検査鋼材の漏洩磁
場探傷を行うことによって脱炭部内欠陥をS/N 比を上げ
て検出することが可能となる。According to the leakage magnetic flux inspection method of the present invention, a magnetic field is applied to a steel material in which a local decarburized portion and a defect in the decarburized portion are made of the same material as the inspection object in advance and magnetized by applying a magnetic field. The magnetic field is detected by a sensor. The detection of the detected electric signal is performed by the synchronous detector, and at this time, the detection phase is variously changed by adjusting the phase shifter, and the difference in the output signal level due to the difference in the phase is examined. Find the maximum phase angle. After setting the detected phase angle using a phase shifter, and performing a leakage magnetic field inspection of the inspection steel material, it is possible to detect defects in the decarburized area by increasing the S / N ratio.
【００１０】[0010]
【実施例】以下本発明をその実施例を示す図面に基づき
具体的に説明する。図１は本発明の漏洩磁束探傷装置の
信号処理系の構成を示すブロック図である。磁化器２
は、コの字型のヨーク2bにコイル2aを巻装したものであ
る。磁化器２はコの字の対辺が検査する鋼材３表面に対
して垂直な方向になるように設置されている。交流電源
１より電流をコイル2aへ通流すると鋼材３表面に対して
平行な方向の水平磁場が発生する。この水平磁場が鋼材
３に印加され、鋼材３表層部は磁化される。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a block diagram showing a configuration of a signal processing system of the magnetic flux leakage inspection apparatus of the present invention. Magnetizer 2
Is formed by winding a coil 2a around a U-shaped yoke 2b. The magnetizer 2 is installed so that the opposite side of the U-shape is in a direction perpendicular to the surface of the steel material 3 to be inspected. When a current is passed from the AC power supply 1 to the coil 2a, a horizontal magnetic field in a direction parallel to the surface of the steel material 3 is generated. This horizontal magnetic field is applied to the steel 3 and the surface layer of the steel 3 is magnetized.
【００１１】鋼材３の表層部近傍には、検出磁場の垂直
成分を電気信号に変換する電磁変換素子を備えたセンサ
４が設置されている。センサ４で検出された電気信号は
同期検波器５へ入力される。同期検波器５は移相器６に
よって検波位相を設定されるように接続されており、移
相器６には基準電圧として電源１の電圧が与えられてい
る。A sensor 4 having an electromagnetic conversion element for converting a vertical component of a detected magnetic field into an electric signal is provided near the surface of the steel material 3. The electric signal detected by the sensor 4 is input to the synchronous detector 5. The synchronous detector 5 is connected so that the detection phase is set by the phase shifter 6, and the phase shifter 6 is supplied with the voltage of the power supply 1 as a reference voltage.
【００１２】図２は検波器５による位相角の変化に対す
る脱炭部内欠陥及び局部的脱炭部のセンサ出力信号レベ
ルの変化を示したものである。横軸は位相角度、縦軸は
出力信号レベルを表している。●印は脱炭部内欠陥があ
る場合の出力、○印は局部的脱炭部がある場合の出力を
それぞれ示している。これらの出力結果は脱炭部内欠陥
がある場合と局部的脱炭部がある場合とでは、位相角度
の相違によって出力信号レベルがそれぞれ異なった値に
なることを表している。FIG. 2 shows a defect in the decarburization section and a change in the sensor output signal level of the local decarburization section with respect to a change in the phase angle by the detector 5. The horizontal axis represents the phase angle, and the vertical axis represents the output signal level. The mark ● indicates the output when there is a defect in the decarburized part, and the mark ○ indicates the output when there is a local decarburized part. These output results show that the output signal level differs depending on the phase angle between the case where there is a defect in the decarburized portion and the case where there is a local decarburized portion.
【００１３】例えば位相角が０°の場合、局部的脱炭部
の出力信号レベルは最大であり、位相角が20°付近では
脱炭部内欠陥の出力信号レベルは最大となる。よって位
相角を20°に設定することにより脱炭部内欠陥の検出能
力は向上する。また、位相角を90°に設定した場合に局
部的脱炭部の出力信号はゼロとなる。よって位相角を90
°に設定すると、脱炭部内欠陥の出力信号だけを検出す
ることができることになるが、出力信号レベルが小さい
ので検出感度を上げる必要がある。For example, when the phase angle is 0 °, the output signal level of the local decarburization unit is maximum, and when the phase angle is around 20 °, the output signal level of a defect in the decarburization unit is maximum. Therefore, by setting the phase angle to 20 °, the ability to detect a defect in the decarburized portion is improved. When the phase angle is set to 90 °, the output signal of the local decarburization unit becomes zero. Therefore, the phase angle is 90
When set to °, it is possible to detect only the output signal of the defect in the decarburized section, but it is necessary to increase the detection sensitivity because the output signal level is low.
【００１４】従って、検査前に予め検査対象と同じ材質
で脱炭部内欠陥及び局部的脱炭部を人工的に作成してお
いた鋼材の漏洩磁場をセンサ４で検出し、検出された電
気信号を同期検波器５により検出し出力させる。このと
き同期検波を移相器６により位相角を種々に変化させて
出力しておく。この出力信号レベルと位相角の関係を図
２の様にグラフ化し、脱炭部内欠陥及び局部的脱炭部の
出力信号がそれぞれ最大となる位相角、また脱炭部内欠
陥の出力信号のみとなる位相角を調べる。その結果より
脱炭部内欠陥の出力信号が最大となる位相角に移相器６
を使用して設定し、その位相角で検査鋼材の漏洩磁場探
傷を行うことによって脱炭部内欠陥をS/N 比を上げて検
出ができる。Therefore, before the inspection, the sensor 4 detects the leakage magnetic field of the steel material in which the defect in the decarburized portion and the local decarburized portion are artificially made of the same material as the object to be inspected beforehand, and the detected electric signal Is detected by the synchronous detector 5 and output. At this time, the synchronous detection is output with the phase angle changed variously by the phase shifter 6. The relationship between the output signal level and the phase angle is graphed as shown in FIG. 2, and only the phase angle at which the output signal of the defect in the decarburization section and the output signal of the local decarburization section become the maximum, and only the output signal of the defect in the decarburization section are obtained. Check the phase angle. Based on the result, the phase shifter 6 sets the phase angle at which the output signal of the defect in the decarburized section becomes maximum.
By setting the phase angle and using a magnetic field leakage inspection of the inspection steel at the phase angle, it is possible to detect defects in the decarburized zone by increasing the S / N ratio.
【００１５】また、上記より図１の装置を使用し、先ず
位相角を脱炭部内欠陥の出力が最大となる位相角に設定
した上で検査鋼材の漏洩磁場探傷を行い、次に位相角を
脱炭部内欠陥のみの出力となる位相角に設定した上でそ
の探傷を行うことにより、脱炭部内欠陥を局部的脱炭部
と弁別して検出可能となる。Further, using the apparatus shown in FIG. 1, the phase angle is first set to the phase angle at which the output of the defect in the decarburized section is maximized, and then the leakage magnetic field flaw detection of the inspection steel material is performed. By performing the flaw detection after setting the phase angle at which only the defect in the decarburized portion is output, the defect in the decarburized portion can be detected and discriminated from the local decarburized portion.
【００１６】図６は信号処理系統を２系統もつ漏洩磁束
探傷装置の構成を示すブロック図である。センサ４で検
出された電気信号は同期検波器５，７へ入力される。同
期検波器５，７はそれぞれ移相器６，８によって検波位
相を設定されるように接続されており、移相器６，８に
は基準電圧として電源１の電圧が与えられている。その
他同一部分には同一符号を付してその説明を省略する。FIG. 6 is a block diagram showing a configuration of a magnetic flux leakage inspection apparatus having two signal processing systems. The electric signal detected by the sensor 4 is input to the synchronous detectors 5, 7. The synchronous detectors 5 and 7 are connected so that the detection phase is set by the phase shifters 6 and 8, respectively, and the voltage of the power supply 1 is given to the phase shifters 6 and 8 as a reference voltage. Other parts that are the same are given the same reference numerals, and description thereof is omitted.
【００１７】このような装置で例えば脱炭部内欠陥の検
出を行う場合、移相器６の調節によって位相角を、脱炭
部内欠陥を最大出力で検出可能な例えば、20°に設定
し、センサ４出力信号の検波を同期検波器５で行い、脱
炭部内欠陥のセンサ出力信号をS/N 比を上げて出力させ
る。そして移相器８の調節によって位相角を脱炭部内欠
陥のみの出力となる90°に設定し、センサ４出力信号の
検波を同期検波器７によって行い、脱炭部内欠陥のみの
センサ出力信号を出力させる。When detecting a defect in the decarburized portion, for example, with such a device, the phase angle is set to, for example, 20 ° at which the defect in the decarburized portion can be detected at the maximum output by adjusting the phase shifter 6, and a sensor is set. The detection of the four output signals is performed by the synchronous detector 5, and the sensor output signal of the defect in the decarburized portion is output with an increased S / N ratio. By adjusting the phase shifter 8, the phase angle is set to 90 °, which is the output of only the defect in the decarburizing section. The output signal of the sensor 4 is detected by the synchronous detector 7, and the sensor output signal of only the defect in the decarburizing section is obtained. Output.
【００１８】また、位相角をそれぞれ20°と90°とに設
定した場合に、20°のときに出力信号が検出され、90°
のときに出力信号が検出されないときには、この検出信
号を局部的脱炭部のみの出力信号と断定できる。そして
移相器、同期検波器を２個ずつ備えることにより、同時
に局部的脱炭部、脱炭部内欠陥を分別して検出可能とな
る。When the phase angles are set to 20 ° and 90 °, respectively, an output signal is detected at 20 °, and
When the output signal is not detected at the time of, the detected signal can be determined as an output signal of only the local decarburization unit. By providing two phase shifters and two synchronous detectors, it is possible to simultaneously detect and detect local decarburized portions and defects in the decarburized portion.
【００１９】[0019]
【発明の効果】以上のように本発明の漏洩磁束探傷法に
あっては、予め移相器を使用して位相角を種々に変化さ
せた上で、脱炭部内欠陥の出力信号が最大となる位相角
を調べ、その位相角に調節することによって高炭素鋼等
で見られる脱炭部内欠陥をS/N比を上げて検出できる。
また、脱炭部内欠陥の出力信号のみとなる位相角を調
べ、その位相角に調節し、検出感度を上げることによっ
て脱炭部内欠陥のみを検出できる。従って、２つの相異
なる位相角で同期検波を行うことにより、同時に局部的
脱炭部と脱炭部内欠陥とを分別して検出可能とする等、
本発明は優れた効果を奏するものである。As described above, according to the leakage magnetic flux detection method of the present invention, after the phase angle is variously changed by using a phase shifter in advance, the output signal of the defect in the decarburized portion is maximized. By examining the phase angle and adjusting it to the phase angle, it is possible to detect defects in the decarburized portion found in high carbon steel etc. by increasing the S / N ratio.
In addition, only the phase angle at which only the output signal of the defect in the decarburized portion is examined, and the phase angle is adjusted to increase the detection sensitivity, whereby only the defect in the decarburized portion can be detected. Therefore, by performing synchronous detection at two different phase angles, it is possible to simultaneously detect a local decarburized portion and a defect in the decarburized portion separately, and so on.
The present invention has excellent effects.
【図１】本発明方法を実施するための信号処理系の構成
を示すブロック図である。FIG. 1 is a block diagram showing a configuration of a signal processing system for implementing a method of the present invention.
【図２】位相角の相違による出力信号レベルの変化を表
すグラフである。FIG. 2 is a graph showing a change in output signal level due to a difference in phase angle.
【図３】本発明方法を実施するための２信号処理系の構
成を示すブロック図である。FIG. 3 is a block diagram showing a configuration of a two-signal processing system for implementing the method of the present invention.
【図４】鋼材表面を磁化させたときの漏洩磁束分布図で
ある。FIG. 4 is a leakage flux distribution diagram when a steel material surface is magnetized.
【図５】欠陥または局部的脱炭部による漏洩磁束の垂直
方向成分分布図である。FIG. 5 is a vertical component distribution diagram of a leakage magnetic flux due to a defect or a local decarburization unit.
【図６】局部的脱炭部内欠陥の漏洩磁束分布と垂直方向
成分分布図である。FIG. 6 is a diagram showing a magnetic flux leakage distribution and a vertical component distribution of a defect in a local decarburization unit.
２ 磁化器 2a コイル 2b ヨーク ３ 鋼材 2 Magnetizer 2a Coil 2b Yoke 3 Steel
Claims (1)
し、表面近傍に生じた漏洩磁場の鋼材表面に垂直な方向
の成分を磁場検出センサにより電気信号として検出し、
検出した電気信号を同期検波器によって検波し、該鋼材
の表面欠陥を検出する漏洩磁束探傷法において、探傷対象鋼材と同材質からなり、脱炭部に人工欠陥を有
する試料に対してその表層部を表面と平行な方向に磁化
し、人工欠陥での漏洩磁束の表面に垂直な方向の成分を
磁場検出センサにより電気信号として検出し、検出した
電気信号を同期検波して出力レベルが最大となる位相角
を検出しておき、探傷対象鋼材について得た電気信号を
検波する際の位相角を試材について求めた位相角に設定
することを特徴とする漏洩磁束探傷法。1. A steel surface layer is magnetized in a direction parallel to a surface, and a component of a leakage magnetic field generated near the surface in a direction perpendicular to the steel surface is detected as an electric signal by a magnetic field detection sensor,
In the magnetic flux leakage detection method in which the detected electric signal is detected by a synchronous detector to detect a surface defect of the steel material, the steel material is made of the same material as the steel material to be inspected, and the decarburized portion has an artificial defect.
Magnetization of the surface layer in a direction parallel to the surface
And the component of the magnetic flux leakage at the artificial defect in the direction perpendicular to the surface
Detected as an electric signal by the magnetic field detection sensor and detected
Phase angle at which output level is maximized by synchronous detection of electrical signal
A magnetic flux leakage detection method, wherein a phase angle at the time of detecting an electric signal obtained from a test target steel material is set to the phase angle obtained for the test material .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7514792A JP2697467B2 (en) | 1992-02-24 | 1992-02-24 | Leakage magnetic flux detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7514792A JP2697467B2 (en) | 1992-02-24 | 1992-02-24 | Leakage magnetic flux detection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05232088A JPH05232088A (en) | 1993-09-07 |
| JP2697467B2 true JP2697467B2 (en) | 1998-01-14 |
Family
ID=13567804
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7514792A Expired - Lifetime JP2697467B2 (en) | 1992-02-24 | 1992-02-24 | Leakage magnetic flux detection method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2697467B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| JP5299800B2 (en) * | 2011-10-25 | 2013-09-25 | 新日鐵住金株式会社 | Carburization detection method |
| CN108562640B (en) * | 2018-03-29 | 2021-05-11 | 南京航空航天大学 | Magnetic leakage signal enhancement structure |
-
1992
- 1992-02-24 JP JP7514792A patent/JP2697467B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05232088A (en) | 1993-09-07 |
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