JP2006064529A - Non-linear electromagnetic ultrasonic sensor, minute flaw detector using it and minute flaw detecting method - Google Patents

Non-linear electromagnetic ultrasonic sensor, minute flaw detector using it and minute flaw detecting method Download PDF

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JP2006064529A
JP2006064529A JP2004247299A JP2004247299A JP2006064529A JP 2006064529 A JP2006064529 A JP 2006064529A JP 2004247299 A JP2004247299 A JP 2004247299A JP 2004247299 A JP2004247299 A JP 2004247299A JP 2006064529 A JP2006064529 A JP 2006064529A
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JP4500895B2 (en
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Riichi Murayama
理一 村山
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Fukuoka Institute of Technology
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-linear electromagnetic ultrasonic sensor capable of detecting a minute flaw of 100 μm or below of a material to be inspected without using a contact medium, a minute flaw detector using it and a minute flaw detecting method. <P>SOLUTION: The non-linear electromagnetic ultrasonic sensor is constituted of the ultrasonic transmitter 1 arranged just above the material P to be inspected to respectively excite surface waves and SH waves using electromagnetic force and a plurality of ultrasonic receivers 2a and 2b having receiving characteristics one and real number multiples with respect to the drive frequency of the ultrasonic transmitter 1. When ultrasonic waves are vertically incident on the slitlike flaw of the material P to be inspected by exciting the surface waves and SH waves from the ultrasonic transmitter 1, the surface waves closely bonds a flaw opening part but the SH waves do not closely bond the flaw opening part. At this time, since the width of the flaw is expanded at the time of tensile vibration of the surface waves, the surface waves do not pass and, since the width of the flaw is narrowed at the time of compression vibration, the surface waves pass. By this constitution, a higher harmonic component is generated and non-linear ultrasonic waves can be detected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、非線形超音波を利用して固体中の１００μｍ以下の微小傷を検出する非線形電磁超音波センサおよびこれを用いた微小傷検出装置並びに微小傷検出方法に関する。   The present invention relates to a non-linear electromagnetic ultrasonic sensor that detects a micro flaw of 100 μm or less in a solid using non-linear ultrasonic waves, a micro flaw detection apparatus using the same, and a micro flaw detection method.

構造材料表面は、応力、腐食環境、高温などにより最も損傷劣化を受けやすい。この劣化損傷を初期段階で検出できれば、主き裂伝播による大規模な事故を避けることができ、また供用条件の調整などにより構造の寿命を延長させることが可能となる。従来の非破壊検査法としては、線形超音波を利用した超音波探傷法が一般的に知られている。   Structural material surfaces are most susceptible to damage and degradation due to stress, corrosive environment, high temperature, and the like. If this deterioration damage can be detected at an early stage, a large-scale accident due to main crack propagation can be avoided, and the life of the structure can be extended by adjusting the service conditions. As a conventional nondestructive inspection method, an ultrasonic flaw detection method using linear ultrasonic waves is generally known.

ところが、線形超音波を利用した超音波探傷法では、開口き裂の検出、評価は可能であるが、初期疲労き裂のようにほとんど閉じたき裂（擬閉口き裂）の検出は極めて困難である。すなわち、擬閉口き裂では入射超音波の一部がき裂面を部分的に通過するため、明瞭な反射波が得られない。また、溶接部介在物のように、見かけ上結合しているが、ほとんど結合強度のない部分、いわゆるキッシングボンド部の場合にも、同様の理由により反射波が得られない。線形超音波による傷検出限界は波長の１／１０程度と言われている。   However, ultrasonic flaw detection using linear ultrasonic waves can detect and evaluate open cracks, but it is extremely difficult to detect almost closed cracks (pseudo-closed cracks) such as initial fatigue cracks. is there. That is, in the quasi-closed crack, a part of the incident ultrasonic wave partially passes through the crack surface, so that a clear reflected wave cannot be obtained. In addition, in the case of a portion that is apparently coupled, such as a welded portion inclusion, but has almost no coupling strength, that is, a so-called kissing bond portion, a reflected wave cannot be obtained for the same reason. It is said that the limit of flaw detection by linear ultrasonic waves is about 1/10 of the wavelength.

ところで、近年では、従来の線形超音波では全く検知できなかった微小クラックに対するセンシングが可能になるという非線形超音波の利点が注目され、検討され始めている。非線形超音波とは、発生した超音波の波形が伝播の前後で歪む現象をいう。非線形超音波ではこの歪み現象の結果、発生した超音波を特徴付ける周波数と音速が変化する（図１３参照。）。   By the way, in recent years, the advantage of nonlinear ultrasonic waves, which enables sensing of microcracks that could not be detected at all by conventional linear ultrasonic waves, has attracted attention and has been studied. Nonlinear ultrasound refers to a phenomenon in which the waveform of the generated ultrasound is distorted before and after propagation. In the nonlinear ultrasonic wave, the frequency and sound speed characterizing the generated ultrasonic wave change as a result of this distortion phenomenon (see FIG. 13).

このような非線形超音波が発生する原因としての構造物は、図１４および図１５に示すように、この構造物を構成する粒子５０とそれらをつなぐばね５１の連続体として考えられる。すなわち、図１４に示すように、超音波が線形に伝播する場合は、超音波の振幅が比較的小さく、ばね５１の弾性限度内のため、入射した超音波の振動の様子がそのまま伝達される。これに対し、図１５に示すように、大振幅の超音波を入射させた場合、ばね５１が弾性限度を超えて伸び縮みするため、入射した超音波の振動の様子が、そのまま伝えられないことになる。   As shown in FIGS. 14 and 15, the structure that causes such nonlinear ultrasonic waves is considered as a continuum of particles 50 constituting the structure and a spring 51 that connects them. That is, as shown in FIG. 14, when the ultrasonic wave propagates linearly, the amplitude of the ultrasonic wave is relatively small and is within the elastic limit of the spring 51, so that the state of vibration of the incident ultrasonic wave is transmitted as it is. . On the other hand, as shown in FIG. 15, when a large-amplitude ultrasonic wave is incident, the spring 51 extends and contracts beyond the elastic limit, so that the vibration state of the incident ultrasonic wave cannot be transmitted as it is. become.

なお、このような非線形超音波現象は、結合力の高い物質では起こりにくいとされており、気体、液体、固体の順番でより起こりにくくなっている。したがって、現状、非線形超音波の利用は医療分野に限られており、人体（実質、水と考えられる）の診断装置として普及しているだけである。一方、工業分野では、扱う対象が主に固体（金属）であるため、非線形現象が起こりにくく、利用されることはなかった。   Note that such a nonlinear ultrasonic phenomenon is less likely to occur in a substance having a high binding force, and is less likely to occur in the order of gas, liquid, and solid. Therefore, at present, the use of nonlinear ultrasonic waves is limited to the medical field and is only widespread as a diagnostic apparatus for the human body (substantially considered to be water). On the other hand, in the industrial field, since the object to be handled is mainly solid (metal), non-linear phenomenon is unlikely to occur and it has not been used.

近年、固体材料で非線形超音波を発生する理由として、上記の原因と異なるものが提案され、検討されている。この非線形超音波現象は、接触型非線形超音波と呼ばれている。すなわち、超音波が、傷部（内部に空孔のある状態）に到達した場合、超音波の反射率は（Ｚ物質−Ｚ空気）／（Ｚ物質＋Ｚ空気）で与えられる。Ｚは音響インピーダンスと言われ、音速×密度で定義される。空気の場合、Ｚ空気＝０．０００４２８（Ｐａ・ｓ／ｍ）、鋼の場合、Ｚ物質＝４６．４（Ｐａ・ｓ／ｍ）となり、代入するとほぼ１００％反射されることになる。一般の超音波による非破壊検査はこの原理を利用して、反射される超音波の大きさを判断し、傷の有無を検出している。 In recent years, the reason why nonlinear ultrasonic waves are generated in a solid material has been proposed and studied differently from the above-mentioned causes. This nonlinear ultrasonic phenomenon is called contact-type nonlinear ultrasonic waves. That is, when an ultrasonic wave reaches a scratched part (a state where there is a void inside), the reflectance of the ultrasonic wave is given by (Z substance- Z air ) / (Z substance + Z air ). Z is said to be acoustic impedance and is defined as sound speed × density. In the case of air , Z air = 0.000428 (Pa · s / m), and in the case of steel, Z substance = 46.4 (Pa · s / m), and when substituted, almost 100% is reflected. General non-destructive inspection using ultrasonic waves uses this principle to determine the size of reflected ultrasonic waves and detect the presence or absence of scratches.

しかしながら、超音波が傷部に到着して、傷部を押したり引いたりした場合に、もし超音波振幅が傷部の空隙の幅よりも大きければ、傷部が押されたときに傷部の空隙がなくなる可能性が考えられる。このような場合、超音波は傷部を通過することになる。したがって、図１６に示すように、入射超音波と波形の異なる超音波が伝播することになる。但し、通常、非破壊検査で用いられる超音波振幅は、ｎｍからサブｎｍ程度と言われており、傷部の空隙の幅がこの値より大きければ、上記の現象は発生しない。   However, when the ultrasonic wave arrives at the wound and is pushed or pulled, if the ultrasonic amplitude is larger than the width of the gap of the wound, There is a possibility that voids disappear. In such a case, the ultrasonic wave passes through the wound. Therefore, as shown in FIG. 16, an ultrasonic wave having a waveform different from that of the incident ultrasonic wave propagates. However, it is generally said that the ultrasonic amplitude used in the nondestructive inspection is about nm to sub-nm, and the above phenomenon does not occur if the width of the void of the scratch is larger than this value.

非線形超音波を用いたき裂検出システムとしては、例えば特許文献１に記載のものが知られている。図１７は非線形超音波の一般的な検出システムとして、２種類の材料の拡散接合部を評価する場合のセンサの配置図である。送信用超音波センサ５２から、一定周波数の超音波を、接触媒質５３を介して材料５４，５５中に入射し、拡散接合部５６を通過した超音波を接触媒質５７を介して反対側面の受信用超音波センサ５８で受信している。受信側超音波センサ５８は、非線形超音波が発生している場合、その主超音波成分は入射した超音波の主超音波成分とは大きく異なる場合が多いので、広い周波数帯域の超音波成分を受信できるように広帯域型を用いる場合が多い。これを用いれば、一定範囲の材料・接合条件のとき、２次高調波振幅を測定して接合強度の予測が可能になると言われている。   As a crack detection system using nonlinear ultrasonic waves, for example, the one described in Patent Document 1 is known. FIG. 17 is a sensor layout diagram for evaluating a diffusion bonding portion of two kinds of materials as a general detection system for nonlinear ultrasonic waves. An ultrasonic wave having a constant frequency is incident on the materials 54 and 55 via the contact medium 53 from the transmission ultrasonic sensor 52, and the ultrasonic wave that has passed through the diffusion bonding portion 56 is received on the opposite side surface via the contact medium 57. It is received by the ultrasonic sensor 58 for use. In the case where nonlinear ultrasonic waves are generated, the reception-side ultrasonic sensor 58 often has a main ultrasonic component that is significantly different from the main ultrasonic component of the incident ultrasonic wave. In many cases, a broadband type is used for reception. If this is used, it is said that the joint strength can be predicted by measuring the second harmonic amplitude when the material and joining conditions are in a certain range.

なお、これらの従来の非線形超音波による非破壊検査評価では、超音波センサとして圧電振動子を用いている。また、この他の超音波センサとしては、例えば、特許文献２に記載のように電磁超音波センサも知られているが、電磁超音波センサは送信効率が悪く、発生する超音波強度（振幅）が小さいので、大強度の振幅が必要な非線形超音波検出は無理であるという常識がある。また、本発明者が開示した電磁超音波センサに関する文献として、例えば非特許文献１，２がある。   In these conventional nondestructive inspection evaluations using nonlinear ultrasonic waves, a piezoelectric vibrator is used as an ultrasonic sensor. As another ultrasonic sensor, for example, an electromagnetic ultrasonic sensor is also known as described in Patent Document 2, but the electromagnetic ultrasonic sensor has poor transmission efficiency and generates ultrasonic intensity (amplitude). Therefore, there is a common sense that nonlinear ultrasonic detection that requires high-intensity amplitude is impossible. Further, for example, there are Non-Patent Documents 1 and 2 as documents relating to the electromagnetic ultrasonic sensor disclosed by the present inventors.

特開２００１−３０５１０９号公報JP 2001-305109 A 特開２００１−１３１１８号公報JP 2001-13118 A 村山理一，「電磁超音波センサの基礎」，非破壊検査，社団法人日本非破壊検査協会，平成１４年２月，第５１巻，第２号，ｐ．６２−６７Riichi Murayama, “Basics of Electromagnetic Ultrasonic Sensors”, Nondestructive Inspection, Japan Nondestructive Inspection Association, February 2002, Vol. 51, No. 2, p. 62-67 村山理一、星原弘征、福重友紀，「ラム波、ＳＨ板波交互励振型電磁超音波探触子の開発」，第２３回超音波エレクトロニクスの基礎と応用に関するシンポジウム講演予稿集，超音波シンポジウム運営委員会，平成１４年１１月７日，ｐ．１７３−１７４Riichi Murayama, Hiroyuki Hoshihara, Yuki Fukushige, “Development of Lamb Wave, SH Plate Wave Alternate Excitation Electromagnetic Ultrasonic Probe”, 23rd Symposium on Basics and Applications of Ultrasonic Electronics, Ultrasonic Symposium Steering Committee, November 7, 2002, p. 173-174

圧電振動子型超音波センサでは、図１８に示すように、センサ５９の前面６０から超音波ビームが発生するため、空中を伝播してから固体材料６１に入射する必要がある（固体材料６１表面はミクロな目で見ればμｍ程度の凹凸が存在するため、その面にセンサ５９を置けば、空気層が必ずできる。）。しかし、前述のように、空気と固体の境界部では、超音波は１００％反射するため、そのままでは超音波ビームが固体材料６１に入射しない。そこで、水や油等の接触媒質６２をセンサ５９の前面６０に塗布することが必須となる。   In the piezoelectric vibrator type ultrasonic sensor, as shown in FIG. 18, since an ultrasonic beam is generated from the front surface 60 of the sensor 59, it is necessary to enter the solid material 61 after propagating through the air (the surface of the solid material 61). Since there are irregularities on the order of μm from the microscopic viewpoint, an air layer is always formed if the sensor 59 is placed on the surface. However, as described above, since the ultrasonic wave is reflected 100% at the boundary between air and solid, the ultrasonic beam does not enter the solid material 61 as it is. Therefore, it is essential to apply a contact medium 62 such as water or oil to the front surface 60 of the sensor 59.

しかし、接触媒質６２を介して超音波ビームを固体材料６１中に入射させた場合、接触媒質６２の非線形性を考慮する必要がある。しかも、接触媒質６２の非線形性は固体材料６１に比べてはるかに大きい。したがって、得られた結果に対し、接触媒質６２の非線形性を排除して固体材料６１のみの非線形性を評価することは極めて困難である。また、接触媒質６２の塗りむらによって誤差も生じる。   However, when the ultrasonic beam is incident on the solid material 61 through the contact medium 62, it is necessary to consider the nonlinearity of the contact medium 62. Moreover, the nonlinearity of the contact medium 62 is much greater than that of the solid material 61. Therefore, it is extremely difficult to evaluate the nonlinearity of only the solid material 61 by eliminating the nonlinearity of the contact medium 62 from the obtained result. An error also occurs due to uneven coating of the contact medium 62.

そこで、本発明においては、接触媒質を使用することなく、非検査材の１００μｍ以下の微小傷を検出することが可能な非線形電磁超音波センサおよびこれを用いた微小傷検出装置並びに微小傷検出方法を提供することを目的とする。   Accordingly, in the present invention, a non-linear electromagnetic ultrasonic sensor capable of detecting a fine flaw of 100 μm or less of a non-inspection material without using a contact medium, a fine flaw detection apparatus using the same, and a flaw detection method The purpose is to provide.

本発明者は、電磁超音波センサによる非線形超音波の検出は無理であるという常識について、塑性歪みに対する非線形超音波を議論する場合は正しいが、接触型で非線形超音波の検出を行う場合、非線形超音波が出るかどうかは傷の隙間と超音波振幅との相対関係で決まるということを見出した。したがって、より微小な１００μｍ以下のクラックに限定されるが、傷の隙間より超音波振幅が大きければ、非線形超音波を検出することが可能となる。   The present inventor is correct when discussing non-linear ultrasonic waves for plastic strain with respect to the common sense that non-linear ultrasonic waves cannot be detected by an electromagnetic ultrasonic sensor. It was found that whether or not ultrasonic waves are emitted is determined by the relative relationship between the scratch gap and the ultrasonic amplitude. Therefore, it is limited to a finer crack of 100 μm or less, but nonlinear ultrasonic waves can be detected if the ultrasonic amplitude is larger than the gap between the scratches.

本発明の非線形電磁超音波センサは、被検査材の直上に配置され電磁力を利用して表面波およびＳＨ（Share Horizontal）波をそれぞれ励振する超音波送信子と、この超音波送信子の駆動周波数に対して１倍および実数倍の受信特性を有する被検査材の直上に配置された複数の超音波受信子とから構成される。   The nonlinear electromagnetic ultrasonic sensor according to the present invention includes an ultrasonic transmitter that is disposed immediately above a material to be inspected and excites surface waves and SH (Share Horizontal) waves using electromagnetic force, and driving of the ultrasonic transmitter. It is composed of a plurality of ultrasonic receivers arranged immediately above a material to be inspected having reception characteristics that are 1 time and real number times the frequency.

ここで、ＳＨ波とは、表面波の中で特に進行方向に対して面内で垂直方向（ＳＨ方向）に振動する成分を持つ波をいう。なお、ＳＨ波は、正式にはＳＨ表面波であるが、一般的にこれを略してＳＨ波という。また、通常、表面波という場合は、このＳＨ波を除外したものをいう。すなわち、表面波とＳＨ波とは、図１の（ａ），（ｂ）に示すように超音波の進行方向に対して振動方向が９０°異なる。なお、被検査材の板厚が超音波長と同程度あるいは波長の数倍程度の薄い板状の固体の場合には、表面波は板波（ラム波）、ＳＨ波はＳＨ板波という。   Here, the SH wave refers to a wave having a component that vibrates in a vertical direction (SH direction) in a plane with respect to a traveling direction among surface waves. The SH wave is formally an SH surface wave, but is generally abbreviated as an SH wave. Further, in general, a surface wave refers to a wave that excludes the SH wave. That is, as shown in FIGS. 1A and 1B, the vibration direction of the surface wave and the SH wave is 90 ° different from the traveling direction of the ultrasonic wave. When the plate thickness of the material to be inspected is a thin plate-like solid having the same thickness as the ultrasonic length or several times the wavelength, the surface wave is called a plate wave (Lamb wave), and the SH wave is called an SH plate wave.

本発明の非線形電磁超音波センサでは、この表面波およびＳＨ波をそれぞれ超音波送信子から励振することで、被検査材のスリット状の傷に対して超音波が垂直に入射する場合、表面波は傷開口部を密着させる作用があるが、ＳＨ波にはこのような作用はない。このとき、表面波の引っ張り振動時には傷の幅が拡がるので表面波は通過しないが、圧縮振動時には傷の幅が狭まるので表面波は通過する。これにより、高調波成分が発生し、非線形超音波を検出することができる。なお、ＳＨ波は、振動方向が傷の幅方向と垂直なため、傷の幅は不変であり、高調波成分の発生はない。一方、このスリット状の傷に対して平行に入射する場合は逆の作用がある。また、斜めに入射する場合は、中間的な作用がある。すなわち、本発明の非線形電磁超音波センサによれば、スリット状の傷の方向に対応した情報が得られる。   In the nonlinear electromagnetic ultrasonic sensor according to the present invention, when the surface wave and the SH wave are respectively excited from the ultrasonic transmitter, the ultrasonic wave is vertically incident on the slit-shaped flaw of the material to be inspected. Has the effect of closely contacting the wound opening, but the SH wave has no such effect. At this time, the surface wave does not pass because the width of the scratch is widened when the surface wave is pulled, but the surface wave passes because the width of the scratch is narrowed when the vibration is compressed. Thereby, a harmonic component is generated and nonlinear ultrasonic waves can be detected. In addition, since the vibration direction of the SH wave is perpendicular to the width direction of the flaw, the width of the flaw is unchanged, and no harmonic component is generated. On the other hand, when the light is incident in parallel to the slit-shaped scratch, there is an opposite effect. Moreover, when it injects diagonally, there exists an intermediate effect | action. That is, according to the nonlinear electromagnetic ultrasonic sensor of the present invention, information corresponding to the direction of the slit-shaped flaw can be obtained.

本発明の電磁力を利用した非線形電磁超音波センサでは、スリット状の傷の長さより超音波振幅が大きくなる１００μｍ以下の長さの微小な傷に限定されるが、非接触でも被検査材に超音波を励振することができることから非検査材と超音波送信子および超音波受信子との間に接触媒質が不要であるため、むしろ正確に微小クラックの有無の判定を行うことが可能となる。また、この非線形電磁超音波センサでは、接触媒質が不要なため、被検査材との間の姿勢さえ水平に一定になるようにすれば、自動走査を行うことは極めて簡単である。   The nonlinear electromagnetic ultrasonic sensor using electromagnetic force according to the present invention is limited to a minute scratch having a length of 100 μm or less in which the ultrasonic amplitude is larger than the length of the slit-like scratch. Since ultrasonic waves can be excited, no contact medium is required between the non-inspection material, the ultrasonic transmitter and the ultrasonic receiver, so it is possible to accurately determine the presence or absence of microcracks. . Further, since this non-linear electromagnetic ultrasonic sensor does not require a contact medium, automatic scanning is extremely simple as long as the posture with respect to the material to be inspected is made to be constant horizontally.

また、電磁超音波センサの場合、その駆動原理から一般的には超音波送信子から左右対称に超音波ビームが発生する。そこで、この特性を逆に利用し、超音波送信子に対して左右対称に複数の超音波受信子（以下、「超音波受信子群」と称す。）を配置することが望ましい。これにより、左右どちらかに傷が存在した場合、左右の超音波受信子群の受信信号特性が大きく変化することになり、傷の有無の判定が容易となる。このような傷の有無の判定方法は、圧電振動子型超音波センサでは実現不可能である。   In the case of an electromagnetic ultrasonic sensor, an ultrasonic beam is generally generated symmetrically from an ultrasonic transmitter due to its driving principle. Therefore, it is desirable to reversely use this characteristic and arrange a plurality of ultrasonic receivers (hereinafter referred to as “ultrasonic receiver group”) symmetrically with respect to the ultrasonic transmitter. As a result, when there is a flaw on either the left or right side, the received signal characteristics of the left and right ultrasonic wave receiver groups greatly change, and it becomes easy to determine whether or not there is a flaw. Such a method for determining the presence or absence of scratches is not feasible with a piezoelectric vibrator type ultrasonic sensor.

また、超音波送信子は、表面波およびＳＨ波をそれぞれ別途励振可能な構成でも良いが、表面波およびＳＨ波を交互に励振可能なものとするのが望ましい。表面波およびＳＨ波を交互に励振可能であることにより、励振する超音波を切り替えるだけで、傷の有無の判定および傷の方向の判定を行うことが可能となる。   The ultrasonic transmitter may be configured to separately excite the surface wave and the SH wave, but it is desirable that the ultrasonic wave transmitter can alternately excite the surface wave and the SH wave. By being able to excite surface waves and SH waves alternately, it is possible to determine the presence / absence of a flaw and the direction of the flaw only by switching the ultrasonic wave to be excited.

被検査材の直上に配置され電磁力を利用して表面波およびＳＨ波をそれぞれ励振する超音波送信子と、この超音波送信子の駆動周波数に対して１倍および実数倍の受信特性を有する被検査材の直上に配置された複数の超音波受信子とから構成される非線形電磁超音波センサによれば、非接触でも被検査材に超音波を励振することができることから接触媒質は不要であり、従来全く不可能であったμｍからサブμｍ領域の微小傷の有無およびその方向を検出することが可能となる。また、これにより、従来の線形超音波では実質破壊直前でしかできなかった余寿命評価を十分事前に予測することが可能となり、真の意味での構造物の安全保障を行うことが可能となる。   An ultrasonic transmitter that is disposed directly above the material to be inspected to excite surface waves and SH waves using electromagnetic force, and has a reception characteristic that is 1 time and real number times the drive frequency of the ultrasonic transmitter. According to the nonlinear electromagnetic ultrasonic sensor composed of a plurality of ultrasonic receivers arranged immediately above the material to be inspected, it is possible to excite ultrasonic waves on the material to be inspected even without contact, so that no contact medium is required. In addition, it is possible to detect the presence or absence and direction of micro-scratches in the μm to sub-μm region, which was impossible in the past. In addition, this makes it possible to predict in advance the remaining life evaluation that could only be performed immediately before substantial destruction with conventional linear ultrasonic waves, and to ensure the security of the structure in a true sense. .

（実施の形態１）
図２は本発明の第１実施形態における微小傷検出装置の概略構成図である。
図２において、本発明の第１実施形態における微小傷検出装置は、被検査材としての薄板Ｐの直上に配置された非線形電磁超音波センサを備える。非線形電磁超音波センサは、超音波送信子１および複数の超音波受信子２ａ，２ｂから構成される。超音波送信子１および複数の超音波受信子２ａ，２ｂは、導線をくし形状に巻いたコイルである。超音波受信子２ａ，２ｂは、超音波送信子１の駆動周波数ｆ0を基本として、それぞれｆ0，２ｆ0の周波数成分を受信する受信特性を有するものである。なお、超音波受信子は、超音波送信子１の駆動周波数ｆ0に対して１倍および実数倍の受信特性を有するものであればよく、上記超音波受信子２ａ，２ｂに加えて、３ｆ0，４ｆ0・・・の周波数成分を受信する超音波受信子（図示せず。）を追加することも可能である。なお、これらの超音波受信子２ａ，２ｂ等は、超音波送信子１を中心として左右対称に配置する。 (Embodiment 1)
FIG. 2 is a schematic configuration diagram of the minute flaw detection apparatus according to the first embodiment of the present invention.
In FIG. 2, the minute flaw detection apparatus according to the first embodiment of the present invention includes a nonlinear electromagnetic ultrasonic sensor arranged immediately above a thin plate P as a material to be inspected. The nonlinear electromagnetic ultrasonic sensor includes an ultrasonic transmitter 1 and a plurality of ultrasonic receivers 2a and 2b. The ultrasonic transmitter 1 and the plural ultrasonic receivers 2a and 2b are coils in which conductive wires are wound in a comb shape. The ultrasonic receivers 2a and 2b have reception characteristics for receiving the frequency components of f 0 and 2f 0 based on the drive frequency f 0 of the ultrasonic transmitter 1 respectively. The ultrasonic receiver only needs to have a reception characteristic that is 1 time and real number times the drive frequency f 0 of the ultrasonic transmitter 1, and in addition to the ultrasonic receivers 2a and 2b, 3f It is also possible to add an ultrasonic receiver (not shown) that receives frequency components of 0 , 4f 0 . The ultrasonic receivers 2a, 2b and the like are arranged symmetrically with respect to the ultrasonic transmitter 1 as a center.

図３の（ａ）、（ｂ）はそれぞれＳＨ板波（ＳＨ波）およびラム波（表面波）の発生メカニズムを示す説明図である。
ＳＨ板波の場合、図３（ａ）に示すように超音波の伝播方向と垂直方向に静磁場をかけ、超音波送信子１のコイル電流による誘導磁場との複合磁場の方向を左右斜め方向に交互に切り替える。薄板Ｐが磁性材料の場合、この複合磁場の方向に磁歪（材料の伸び縮み）が発生し、その結果、超音波の伝播方向に対して垂直で面内の力が発生し、ＳＨ板波の駆動源となる。一方、ラム波の場合は、図３（ｂ）に示すように超音波の伝播方向に印加された静磁場と同方向で一定間隔ごとに発生する誘導磁場による複合磁場変化が発生し、超音波の伝播方向の磁歪振動を起こし、ラム波に変換される。 (A), (b) of FIG. 3 is explanatory drawing which shows the generation | occurrence | production mechanism of SH plate wave (SH wave) and Lamb wave (surface wave), respectively.
In the case of an SH plate wave, as shown in FIG. 3A, a static magnetic field is applied in a direction perpendicular to the propagation direction of the ultrasonic wave, and the direction of the composite magnetic field with the induction magnetic field generated by the coil current of the ultrasonic transmitter 1 is set obliquely to the left and right. Switch alternately. When the thin plate P is a magnetic material, magnetostriction (stretching / shrinking of the material) occurs in the direction of the composite magnetic field. As a result, an in-plane force is generated perpendicular to the propagation direction of the ultrasonic wave, and the SH plate wave It becomes a driving source. On the other hand, in the case of a Lamb wave, as shown in FIG. 3B, a composite magnetic field change is generated by an induced magnetic field generated at regular intervals in the same direction as the static magnetic field applied in the ultrasonic wave propagation direction. This causes magnetostrictive vibration in the propagation direction of, and is converted to Lamb waves.

図２に示す本実施形態における微小傷検出装置では、この両モードの波の励振を１つの非線形電磁超音波センサで実現できるように、超音波送信子１および超音波受信子２ａ，２ｂの配置方向に対して、平行方向および垂直方向にそれぞれ静磁場が負荷できる構造となっている。すなわち、超音波送信子１および複数の超音波受信子２ａ，２ｂの上下左右にそれぞれ一対の電磁石３ａ，３ｂ，４ａ，４ｂが配置され、電源５から供給する電力の切り替えスイッチ６により上下左右の電磁石３ａ，３ｂ，４ａ，４ｂの駆動を切り替える。   In the microflaw detection apparatus according to the present embodiment shown in FIG. 2, the arrangement of the ultrasonic transmitter 1 and the ultrasonic receivers 2a and 2b so that the excitation of the waves in both modes can be realized by one nonlinear electromagnetic ultrasonic sensor. It has a structure in which a static magnetic field can be loaded in each of a parallel direction and a vertical direction with respect to the direction. That is, a pair of electromagnets 3 a, 3 b, 4 a, 4 b are respectively arranged on the top, bottom, left and right of the ultrasonic transmitter 1 and the plurality of ultrasonic receivers 2 a, 2 b, The driving of the electromagnets 3a, 3b, 4a, 4b is switched.

これにより、ラム波を発生させる場合は、切り替えスイッチ６によって左右の電磁石３ａ，３ｂが駆動され、超音波送信子１のコイル対して水平に静磁場が発生する。また、これと同時に、超音波送信子１に基本周波数ｆ0の周波数成分を持つ高周波のパルス電気信号がパルサー７より与えられる。この両者の相互作用により薄板Ｐにラム波が発生する。この原理の場合、超音波送信子１に対して左右の区別はないため、左右対称にラム波が発生する。発生したラム波は、左右の超音波受信子２ａ，２ｂを通過したときに、それぞれ電気信号に変換される。 As a result, when a Lamb wave is generated, the left and right electromagnets 3 a and 3 b are driven by the changeover switch 6, and a static magnetic field is generated horizontally with respect to the coil of the ultrasonic transmitter 1. At the same time, a high-frequency pulse electric signal having a frequency component of the fundamental frequency f 0 is supplied from the pulsar 7 to the ultrasonic transmitter 1. A lamb wave is generated in the thin plate P by the interaction between the two. In the case of this principle, since there is no distinction between right and left with respect to the ultrasonic transmitter 1, Lamb waves are generated symmetrically. The generated Lamb waves are converted into electrical signals when passing through the left and right ultrasonic receivers 2a and 2b.

超音波受信子２ａ，２ｂによって変換された電気信号は、切り替えスイッチ８を経て増幅器９により増幅され、周波数解析器１０により周波数解析が行われる。もし、上記ラム波の伝播過程に傷があり、前述の非線形超音波発生条件に合致していれば、波形に歪みが発生することになり、周波数解析器１０によりその情報が獲得できる。   The electrical signals converted by the ultrasonic receivers 2a and 2b are amplified by the amplifier 9 via the changeover switch 8, and the frequency analysis is performed by the frequency analyzer 10. If there is a flaw in the propagation process of the Lamb wave and the above-mentioned nonlinear ultrasonic wave generation conditions are met, the waveform is distorted, and the information can be acquired by the frequency analyzer 10.

次に、ＳＨ板波を発生させる場合は、切り替えスイッチ６によって上下の電磁石４ａ，４ｂが駆動される。超音波送信子１は上述と同様に駆動されており、両者の相互作用によりＳＨ板波が発生する。以下の過程は同じである。   Next, when the SH plate wave is generated, the upper and lower electromagnets 4 a and 4 b are driven by the changeover switch 6. The ultrasonic transmitter 1 is driven in the same manner as described above, and an SH plate wave is generated by the interaction between the two. The following process is the same.

図４は図２の微小傷検出装置による微小クラックの評価手順を示している。   FIG. 4 shows a procedure for evaluating microcracks by the microscratch detection apparatus of FIG.

（Ｓ１０１）
切り替えスイッチ６により左右の電磁石３ａ，３ｂを駆動し、ラム波モードで超音波送信子１より超音波（ラム波ｆ0）を送信する。
（Ｓ１０２）
左右の超音波受信子２ａ，２ｂ群によりこのラム波ｆ0を検出する。
（Ｓ１０３）
超音波送信子１と超音波受信子２ａ，２ｂの各組み合わせで受信信号の周波数成分を解析する。基本周波数ｆ0の１倍および実数倍２ｆ0，３ｆ0，・・・の周波数成分比を左側と右側それぞれで算出する。
（Ｓ１０４）
左右両側の算出値が同じであれば傷はどちら側にもないことになり、左右両側の算出値が異なれば超音波の伝播方向に対して垂直方向の微小傷が存在することになる。 (S101)
The left and right electromagnets 3a and 3b are driven by the changeover switch 6, and an ultrasonic wave (Lamb wave f 0 ) is transmitted from the ultrasonic transmitter 1 in the Lamb wave mode.
(S102)
The Lamb wave f 0 is detected by the left and right ultrasonic receivers 2a and 2b.
(S103)
The frequency component of the received signal is analyzed by each combination of the ultrasonic transmitter 1 and the ultrasonic receivers 2a and 2b. The frequency component ratio of 1 times the fundamental frequency f 0 and real numbers 2f 0 , 3f 0 ,... Is calculated on the left side and the right side, respectively.
(S104)
If the calculated values on the left and right sides are the same, there will be no scratch on either side, and if the calculated values on the left and right sides are different, there will be a minute flaw in the direction perpendicular to the propagation direction of the ultrasonic waves.

（Ｓ１０５）
切り替えスイッチ６により上下の電磁石４ａ，４ｂを駆動し、ＳＨ板波モードで超音波送信子１より超音波（ＳＨ板波ｆ0）を送信する。
（Ｓ１０６）
左右の超音波受信子２ａ，２ｂ群によりこのＳＨ板波ｆ0を検出する。
（Ｓ１０７）
超音波送信子１と超音波受信子２ａ，２ｂの各組み合わせで受信信号の周波数成分を解析する。基本周波数ｆ0の１倍および実数倍２ｆ0，３ｆ0，・・・の周波数成分比を左側と右側それぞれで算出する。
（Ｓ１０８）
左右両側の算出値が同じであれば傷はどちら側にもないことになり、左右両側の算出値が異なれば超音波の伝播方向に対して平行方向の微小傷が存在することになる。 (S105)
The changeover switch 6 drives the upper and lower electromagnets 4a and 4b, and transmits ultrasonic waves (SH plate wave f 0 ) from the ultrasonic transmitter 1 in the SH plate wave mode.
(S106)
The SH plate wave f 0 is detected by the left and right ultrasonic receivers 2a and 2b.
(S107)
The frequency component of the received signal is analyzed by each combination of the ultrasonic transmitter 1 and the ultrasonic receivers 2a and 2b. The frequency component ratio of 1 times the fundamental frequency f 0 and real numbers 2f 0 , 3f 0 ,... Is calculated on the left side and the right side, respectively.
(S108)
If the calculated values on the left and right sides are the same, there will be no scratch on either side, and if the calculated values on the left and right sides are different, there will be a minute flaw parallel to the ultrasonic propagation direction.

このように、薄板Ｐ内に微小クラックが存在した場合、左側の超音波受信子２ａ，２ｂ群と右側の超音波受信子２ａ，２ｂ群とで、評価結果が大きく異なることになるので、信頼度の高いデータが得られる。   As described above, when there are micro cracks in the thin plate P, the evaluation results greatly differ between the left ultrasonic receivers 2a and 2b and the right ultrasonic receivers 2a and 2b. High degree of data can be obtained.

（実施の形態２）
図５および図６は本発明の第２実施形態における微小傷検出装置の概略構成図である。
本発明の第２実施形態における微小傷検出装置では、非線形電磁超音波センサによりＳＨ板波およびラム波をそれぞれ別々に発生させるため、図５に示すように電磁石３ａ，３ｂと図６に示すように電磁石４ａ，４ｂとをそれぞれ別構成としたものである。その他の構成については第１実施形態と同様である。 (Embodiment 2)
FIG. 5 and FIG. 6 are schematic configuration diagrams of a minute flaw detection apparatus according to the second embodiment of the present invention.
In the microflaw detection apparatus according to the second embodiment of the present invention, the SH plate wave and the Lamb wave are separately generated by the nonlinear electromagnetic ultrasonic sensor, so that the electromagnets 3a and 3b and the electromagnet 3a and 3b as shown in FIG. The electromagnets 4a and 4b are separately configured. Other configurations are the same as those in the first embodiment.

このような構成であっても、第１実施形態と同様に、図５に示す電磁石３ａ，３ｂを駆動することでラム波を送信し、左右両側の超音波受信子２ａ，２ｂにより受信した信号の周波数成分を解析することで、超音波の伝播方向に対して垂直方向の傷の有無を検出することが可能である。また、図６に示す電磁石４ａ，４ｂを駆動することでＳＨ板波を送信し、左右両側の超音波受信子２ａ，２ｂにより受信した信号の周波数成分を解析することで、超音波の伝播方向に対して平行方向の傷の有無を検出することが可能である。   Even in such a configuration, similarly to the first embodiment, the Lamb waves are transmitted by driving the electromagnets 3a and 3b shown in FIG. 5, and the signals received by the left and right ultrasonic receivers 2a and 2b are transmitted. By analyzing the frequency component, it is possible to detect the presence or absence of a flaw in the direction perpendicular to the propagation direction of the ultrasonic wave. Further, by driving the electromagnets 4a and 4b shown in FIG. 6, SH plate waves are transmitted, and by analyzing the frequency components of the signals received by the left and right ultrasonic receivers 2a and 2b, the propagation direction of the ultrasonic waves It is possible to detect the presence or absence of scratches in the parallel direction.

（実施の形態３）
図７および図８は本発明の第３実施形態における微小傷検出装置の概略構成図である。
本発明の第３実施形態における微小傷検出装置では、超音波送信子１の左右一方だけに超音波受信子２ａ，２ｂを配置したものである。その他の構成については第２実施形態と同様である。 (Embodiment 3)
7 and 8 are schematic configuration diagrams of a micro-scratch detection device according to the third embodiment of the present invention.
In the microflaw detection apparatus according to the third embodiment of the present invention, the ultrasonic receivers 2a and 2b are arranged only on the left and right sides of the ultrasonic transmitter 1. Other configurations are the same as those of the second embodiment.

このような構成であっても、図７に示す電磁石３ａ，３ｂを駆動することでラム波を送信し、左右一方の超音波受信子２ａ，２ｂにより受信した信号の周波数成分を解析することで、超音波の伝播方向に対して垂直方向の傷の有無を検出することが可能である。また、図８に示す電磁石４ａ，４ｂを駆動することでＳＨ板波を送信し、左右一方の超音波受信子２ａ，２ｂにより受信した信号の周波数成分を解析することで、超音波の伝播方向に対して平行方向の傷の有無を検出することが可能である。   Even in such a configuration, the electromagnets 3a and 3b shown in FIG. 7 are driven to transmit Lamb waves, and the frequency components of the signals received by the left and right ultrasonic receivers 2a and 2b are analyzed. It is possible to detect the presence or absence of a flaw in the direction perpendicular to the ultrasonic wave propagation direction. Further, by transmitting the SH plate wave by driving the electromagnets 4a and 4b shown in FIG. 8 and analyzing the frequency components of the signals received by the left and right ultrasonic receivers 2a and 2b, the propagation direction of the ultrasonic waves It is possible to detect the presence or absence of scratches in the parallel direction.

図９は超音波送信子１の駆動周波数を１ＭＨｚ、超音波受信子２ａ，２ｂの受信特性を１ＭＨｚ、２ＭＨｚとした場合のラム波モードによる評価結果を示している。本実施例では、薄板（鋼板）Ｐに微小スリットＳを加工して評価した。ラム波は図９（ａ）に示すようにスリットＳに対して垂直に入射した。なお、本発明の微小傷検出装置の適用範囲は本来さらにスリット幅の狭い範囲を狙ったものであるが、機械加工で可能な限り小さく加工した。また、表記しているスリット幅は開口部の幅であり、底部は極めて細くなっていることが予想される。   FIG. 9 shows the evaluation results in the Lamb wave mode when the drive frequency of the ultrasonic transmitter 1 is 1 MHz and the reception characteristics of the ultrasonic receivers 2a and 2b are 1 MHz and 2 MHz. In this example, evaluation was made by processing the micro slits S in the thin plate (steel plate) P. The Lamb wave entered perpendicularly to the slit S as shown in FIG. In addition, although the application range of the micro flaw detection apparatus of the present invention is originally aimed at a range where the slit width is narrower, it was processed as small as possible by machining. In addition, the indicated slit width is the width of the opening, and the bottom is expected to be extremely thin.

図９（ｂ）および（ｃ）はスリット幅２０μｍの場合の受信信号を周波数解析した結果であり、それぞれの主周波数成分の強度比について、スリット幅ごとにプロットしたものが同図（ｄ）である。この図から、スリット幅２０〜３０μｍの場合のスリット底部の幅が超音波振動の振幅と同程度となり、主周波数成分の強度比すなわち送信超音波の主周波数成分１ＭＨｚに対して主周波数成分２ＭＨｚが強く発生していることが分かる。   FIGS. 9B and 9C show the results of frequency analysis of the received signal when the slit width is 20 μm. The intensity ratio of each main frequency component is plotted for each slit width in FIG. is there. From this figure, the width of the slit bottom when the slit width is 20 to 30 μm is approximately the same as the amplitude of the ultrasonic vibration, and the main frequency component 2 MHz with respect to the intensity ratio of the main frequency component, that is, the main frequency component 1 MHz of the transmitted ultrasonic wave It can be seen that it occurs strongly.

図１０はＳＨ板波をスリットに対して垂直に入射した場合を示している。この場合は前述のように、ＳＨ板波がスリット幅を狭める効果がないため、有意差が生じていない。   FIG. 10 shows a case where an SH plate wave is incident perpendicular to the slit. In this case, as described above, since the SH plate wave has no effect of narrowing the slit width, no significant difference occurs.

図１１はラム波およびＳＨ板波をスリットに対して平行に入射した場合の例である。この場合、前述のように、ＳＨ板波にスリット幅を狭める効果が生じるため、有意差が生じている。   FIG. 11 shows an example in which a Lamb wave and an SH plate wave are incident in parallel to the slit. In this case, as described above, the effect of narrowing the slit width is generated in the SH plate wave, so that a significant difference is generated.

図１２は本発明の非線形電磁超音波センサを用いた微小傷検出装置と従来の線形超音波センサを用いた微小傷検出装置とを比較した図である。
以上のように、本発明の非線形電磁超音波センサを用いた微小傷検出装置によれば、従来全く不可能であったμｍ〜サブμｍ領域の微小傷を検出することが可能となる。その結果、例えば、図１２に示すように従来の線形超音波センサを用いた場合の余寿命評価が実質破壊直前でしかできず、効果がなかったのに対し、本発明の非線形電磁超音波センサを用いた場合、充分に事前の予測が可能となり、真の意味での構造物の安全保障を行うことが可能となる。 FIG. 12 is a diagram comparing a micro-scratch detection apparatus using the nonlinear electromagnetic ultrasonic sensor of the present invention and a micro-scratch detection apparatus using a conventional linear ultrasonic sensor.
As described above, according to the minute flaw detection apparatus using the nonlinear electromagnetic ultrasonic sensor of the present invention, it is possible to detect a minute flaw in the μm to sub-μm region which has never been possible in the past. As a result, for example, as shown in FIG. 12, when the conventional linear ultrasonic sensor is used, the remaining life evaluation can be performed only immediately before the substantial destruction, and the nonlinear electromagnetic ultrasonic sensor of the present invention is not effective. When is used, it is possible to make a prediction in advance, and it is possible to ensure the security of the structure in a true sense.

本発明の非線形電磁超音波センサおよびこれを用いた微小傷検出装置並びに微小傷検出方法は、従来の線形超音波を用いた超音波試験で検出できない初期の疲労、クリープ損傷の検出、キッシングボンド、微小クラックを検出することで原子力発電所や火力発電所の安全確保のため極めて厳しい検査レベルを必要とする構造物の検査、燃料タンクやガス配管などの余寿命評価等に有用である。   Non-linear electromagnetic ultrasonic sensor of the present invention, a micro-scratch detection apparatus and a micro-scratch detection method using the same, initial fatigue that cannot be detected by an ultrasonic test using conventional linear ultrasonic waves, detection of creep damage, kissing bond, Detecting microcracks is useful for inspection of structures that require extremely strict inspection levels to ensure the safety of nuclear power plants and thermal power plants, and evaluation of remaining life of fuel tanks and gas pipes.

表面波とＳＨ波による非線形超音波発生のメカニズムの違いを示す説明図である。It is explanatory drawing which shows the difference in the mechanism of the nonlinear ultrasonic wave generation by a surface wave and SH wave. 本発明の第１実施形態における微小傷検出装置の概略構成図である。It is a schematic block diagram of the micro flaw detection apparatus in 1st Embodiment of this invention. （ａ）はＳＨ板波（ＳＨ波）の発生メカニズムを示す説明図、（ｂ）はラム波（表面波）の発生メカニズムを示す説明図である。(A) is explanatory drawing which shows the generation mechanism of SH plate wave (SH wave), (b) is explanatory drawing which shows the generation mechanism of Lamb wave (surface wave). 図２の微小傷検出装置による微小クラックの評価手順を示すフロー図である。It is a flowchart which shows the evaluation procedure of the micro crack by the micro flaw detection apparatus of FIG. 本発明の第２実施形態における微小傷検出装置の概略構成図である。It is a schematic block diagram of the micro flaw detection apparatus in 2nd Embodiment of this invention. 本発明の第２実施形態における微小傷検出装置の概略構成図である。It is a schematic block diagram of the micro flaw detection apparatus in 2nd Embodiment of this invention. 本発明の第３実施形態における微小傷検出装置の概略構成図である。It is a schematic block diagram of the micro flaw detection apparatus in 3rd Embodiment of this invention. 本発明の第３実施形態における微小傷検出装置の概略構成図である。It is a schematic block diagram of the micro flaw detection apparatus in 3rd Embodiment of this invention. ラム波モードによる評価結果を示す図である。It is a figure which shows the evaluation result by Lamb wave mode. ＳＨ板波をスリットに対して垂直に入射した場合の評価結果を示す図である。It is a figure which shows the evaluation result at the time of entering SH plate wave perpendicularly | vertically with respect to a slit. ラム波およびＳＨ板波をスリットに対して平行に入射した場合の評価結果を示す図である。It is a figure which shows the evaluation result at the time of entering a Lamb wave and SH plate wave in parallel with respect to a slit. 本発明の非線形電磁超音波センサを用いた微小傷検出装置と従来の線形超音波センサを用いた微小傷検出装置とを比較した図である。It is the figure which compared the micro flaw detection apparatus using the nonlinear electromagnetic ultrasonic sensor of this invention, and the micro flaw detection apparatus using the conventional linear ultrasonic sensor. 非線形超音波の説明図である。It is explanatory drawing of a nonlinear ultrasonic wave. ばねの弾性限度内で超音波が伝播する様子を示す図である。It is a figure which shows a mode that an ultrasonic wave propagates within the elastic limit of a spring. ばねの弾性限度を超えて超音波が伝播する様子を示す図である。It is a figure which shows a mode that an ultrasonic wave propagates exceeding the elastic limit of a spring. 超音波振幅が傷の空隙の幅よりも狭い場合の超音波伝播の様子を示す図である。It is a figure which shows the mode of ultrasonic propagation in case an ultrasonic amplitude is narrower than the width | variety of the space | gap of a crack. 非線形超音波の一般的な検出システムとして、２種類の材料の拡散接合部を評価する場合のセンサの配置図である。It is a sensor layout in the case of evaluating diffusion junctions of two kinds of materials as a general detection system for nonlinear ultrasonic waves. 圧電振動子型超音波センサによる超音波伝播の様子を示す図である。It is a figure which shows the mode of the ultrasonic wave propagation by a piezoelectric vibrator type ultrasonic sensor.

符号の説明Explanation of symbols

１ 超音波送信子
２ａ，２ｂ 超音波受信子
３ａ，３ｂ，４ａ，４ｂ 電磁石
５ 電源
６，８ 切り替えスイッチ
７ パルサー
９ 増幅器
１０ 周波数解析器 DESCRIPTION OF SYMBOLS 1 Ultrasonic transmitter 2a, 2b Ultrasonic receiver 3a, 3b, 4a, 4b Electromagnet 5 Power supply 6, 8 Changeover switch 7 Pulsar 9 Amplifier 10 Frequency analyzer

Claims (5)

被検査材の直上に配置され電磁力を利用して表面波およびＳＨ波をそれぞれ励振する超音波送信子と、この超音波送信子の駆動周波数に対して１倍および実数倍の受信特性を有する前記被検査材の直上に配置された複数の超音波受信子とから構成される非線形電磁超音波センサ。   An ultrasonic transmitter that is disposed directly above the material to be inspected to excite surface waves and SH waves using electromagnetic force, and has a reception characteristic that is 1 time and real number times the drive frequency of the ultrasonic transmitter. A non-linear electromagnetic ultrasonic sensor comprising a plurality of ultrasonic receivers arranged immediately above the material to be inspected. 前記複数の超音波受信子は、前記超音波送信子に対して左右対称に配置したものである請求項１記載の非線形電磁超音波センサ。   The nonlinear electromagnetic ultrasonic sensor according to claim 1, wherein the plurality of ultrasonic receivers are arranged symmetrically with respect to the ultrasonic transmitter. 前記超音波送信子は、前記表面波およびＳＨ波を交互に励振可能なものである請求項１または２に記載の非線形電磁超音波センサ。   The nonlinear electromagnetic ultrasonic sensor according to claim 1, wherein the ultrasonic transmitter is capable of alternately exciting the surface wave and the SH wave. 請求項１から３のいずれかに記載の非線形電磁超音波センサと、この非線形電磁超音波センサにより受信した電気信号を増幅する増幅器と、この増幅器による増幅後の電気信号に基づいて周波数解析を行う解析器とを有する微小傷検出装置。   The nonlinear electromagnetic ultrasonic sensor according to any one of claims 1 to 3, an amplifier for amplifying an electric signal received by the nonlinear electromagnetic ultrasonic sensor, and frequency analysis based on the electric signal amplified by the amplifier A micro-scratch detection device having an analyzer. 被検査材の直上に配置され電磁力を利用して超音波送信子から表面波およびＳＨ波をそれぞれ送信し、
前記超音波送信子の駆動周波数に対して１倍および実数倍の受信特性を有する前記被検査材の直上に配置された複数の超音波受信子により前記被検査材を伝播した超音波信号をそれぞれ受信し、
前記複数の超音波受信子により受信した電気信号を増幅し、
この増幅後の電気信号に基づいて周波数解析を行う
微小傷検出方法。 The surface wave and the SH wave are respectively transmitted from the ultrasonic transmitter by using the electromagnetic force arranged immediately above the material to be inspected.
Ultrasonic signals propagated through the inspection object by a plurality of ultrasonic receivers arranged immediately above the inspection object having reception characteristics of 1 and real number times the driving frequency of the ultrasonic transmitter, respectively. Receive
Amplifying electrical signals received by the plurality of ultrasonic receivers;
A micro-scratch detection method that performs frequency analysis based on the amplified electrical signal.
JP2004247299A 2004-08-26 2004-08-26 Non-linear electromagnetic ultrasonic sensor, micro-scratch detection apparatus using the same, and micro-scratch detection method Expired - Fee Related JP4500895B2 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007285893A (en) * 2006-04-17 2007-11-01 Kobe Steel Ltd Device for electromagnetic ultrasonic inspection and inspection method of material to be inspected
KR101053422B1 (en) 2008-12-22 2011-08-01 주식회사 포스코 Inner defect detection system and detection method of steel plate using nonlinear ultrasonic generation
CN107064296A (en) * 2017-01-18 2017-08-18 中国特种设备检测研究院 Type multimode electromagnetic ultrasonic testing system and electromagnetic ultrasonic transducer

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007285893A (en) * 2006-04-17 2007-11-01 Kobe Steel Ltd Device for electromagnetic ultrasonic inspection and inspection method of material to be inspected
KR101053422B1 (en) 2008-12-22 2011-08-01 주식회사 포스코 Inner defect detection system and detection method of steel plate using nonlinear ultrasonic generation
CN107064296A (en) * 2017-01-18 2017-08-18 中国特种设备检测研究院 Type multimode electromagnetic ultrasonic testing system and electromagnetic ultrasonic transducer
CN107064296B (en) * 2017-01-18 2024-04-05 中国特种设备检测研究院 Multi-mode electromagnetic ultrasonic detection system and electromagnetic ultrasonic sensor

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