JP3754669B2

JP3754669B2 - Ultrasonic flaw detection apparatus and ultrasonic flaw detection method

Info

Publication number: JP3754669B2
Application number: JP2002300638A
Authority: JP
Inventors: 憲一郎土屋
Original assignee: Ｊｆｅ工建株式会社
Priority date: 2002-10-15
Filing date: 2002-10-15
Publication date: 2006-03-15
Anticipated expiration: 2022-10-15
Also published as: JP2004138392A

Description

【０００１】
【発明の属する技術分野】
本発明は、入射探触子で検査対象に超音波を入射し、検査対象を伝達した超音波を受信探触子で受信する超音波探傷装置及び超音波探傷方法に関する。
【０００２】
【従来の技術】
従来から、検査対象を破壊することなく、検査対象に内在する欠陥を検査する超音波探傷として、ＴＯＦＤ（ＴｉｍｅＯｆＦｌｉｇｈｔＤｉｆｆｒａｃｔｉｏｎ）法が知られている。このＴＯＦＤ法は、図９に示すように、超音波を検査対象に入射させる入射探触子１１０と、超音波を受信する受信探触子１１１とを対向させて検査対象１１２の表面に接触させ、入射探触子１１０から縦波超音波を検査対象１１２に入射させて、内在する欠陥１１３の上端１１４および下端１１５で発生した回折波を受信探触子１１１で受信することで欠陥１１３を探傷する方法である。かかるＴＯＦＤ法では、検査対象１１２の表面に沿って伝播するラテラル波、欠陥１１３の上端１１４及び下端１１５で発生する回折波１２１，１２２、並びに検査対象１１２の底面で反射するエコー波１２３の、入射探触子１１０から受信探触子１１１へ伝播する時間差と音速との関係により欠陥の位置と大きさを正確に検査することができる。
【０００３】
具体的には、図１０に示すようにオシロスコープ等の波形を映し出すことができるモニタ装置に、ラテラル波１２０、欠陥の上端で発生する回折波１２１、欠陥の下端で発生する回折波１２２、並びにエコー波１２３を映し出す。そして、各波形の伝播時間を分析することで欠陥の位置と欠陥の大きさを特定している。
【０００４】
このようなＴＯＦＤ法による非破壊検査方法は既に複数の先行技術が開示されている（例えば、特許文献１参照）。
【０００５】
【特許文献１】
特開２００２−１３９４７９号公報（段落番号００１２〜００１３、図１、段落番号０００３、図６）。
【０００６】
【発明が解決しようとする課題】
しかしながら、このＴＯＦＤ法は、検査対象が平面状に形成され、入射探触子と受信探触子とがともに同一平面上に配置されている必要がある。このため、橋桁などの複雑な形状を有する構造物に対しては、ＴＯＦＤ法によって内部欠陥を探傷することが不可能である。近年、橋桁等の複雑な形状を有する構造物について、検査対象を破壊することなく検査できる新たな非破壊検査方法が社会的に望まれている。
【０００７】
本発明は、かかる要請に応えるためになされたものであり、複雑な形状を有する検査対象を破壊することなく、内在する欠陥をきわめて容易に探傷することができる超音波探傷装置及び超音波探傷方法を提供することを目的とする。
【０００８】
【課題を解決するための手段】
本発明では、上記課題を解決するために、互いの表面が交差するように接合された部材の接合部を検査部位とする超音波探傷装置において、接合された一方の部材の表面に配置され、前記検査部位に向けて超音波を入射せしめる入射探触子と、他方の部材の表面に配置され、前記入射探触子が入射せしめた超音波を受信する受信探触子とを備え、前記入射探触子は、前記検査部位との結ぶ線と一方の前記部材の表面とが所定の傾斜角をなすよう配されると共に、前記受信探触子は、前記検査部位との結ぶ線と他方の前記部材の表面とが所定の傾斜角をなすよう配され、前記入射探触子は、発信面が前記検査部位側に向けられてなり、超音波を発信する発信素子から所定の広がり角度の発信角で前記検査部位に向けて超音波を入射し、前記受信探触子は、受信面が前記検査部位側に向けられてなり、前記入射探触子から入射されて前記検査部位を伝達した超音波を受信する受信素子を内蔵し、所定の広がり角度である受信可能角内の超音波のみを受信し、前記受信面と他方の前記部材の表面とのなす傾斜角が、前記発信面と一方の前記部材の表面とのなす傾斜角より大きく形成されて、前記受信面が前記発信面より相対的に前記検査部位側に大きく傾けられていると共に、前記受信可能角が、前記発信角より小さく形成されている超音波探傷装置を採用した。
【０００９】
また、互いの表面が交差するように接合された部材の接合部を検査部位とし、接合された一方の部材の表面に、前記検査部位に向けて超音波を入射せしめる入射探触子を配置すると共に、他方の部材の表面に前記入射探触子が入射せしめた超音波を受信する受信探触子を配置し、前記入射探触子から一方の前記部材の表面と所定の角度をなし、かつ、所定の広がり角の発信角で超音波を前記検査部位に向けて入射させ、前記受信探触子によって受信する前記検査部位から伝達された超音波の方向と他方の前記部材とのなす角が、前記入射探触子が入射した超音波と一方の前記部材の表面とがなす角度より小さな角度となるようにすると共に、前記受信探触子を基準とする広がり角である受信可能角が、前記発信角より小さな広がり角である受信可能角の範囲内に前記検査部位から伝達された超音波のみを受信することを特徴とする超音波探傷方法により検査対象を探傷する。
【００１０】
本発明によれば、入射探触子から検査部位へ相対的に広い範囲に超音波が入射され、探傷しようとする部位に漏れなく超音波が到達される。その一方で、受信探触子は、接触させた他方の部材の表面に相対的に近い方向で、かつ、より小さな角度の範囲内の超音波のみを受信する。これにより、複雑な形状を有する検査対象に関しても、入射探触子から入射され、検査部位を伝達した超音波を受信探触子が確実に受信する。しかも、受信探触子が、探傷しようとする、限られた範囲から伝達された超音波のみを受信するため、余分なエコー波や回折波を受信せず、高い信頼性を実現する。
【００１１】
また、一方の前記部材の表面と他方の前記部材の表面とがなす角に応じて、少なくとも一方の前記部材の表面とのなす角又は前記発信角のいずれか一方を変化させて前記入射探触子から超音波を入射すると共に、一方の前記部材の表面と他方の前記部材の表面とがなす角に応じて、少なくとも他方の前記部材の表面とのなす角又は前記受信可能角のいずれか一方を変化させて、前記入射探触子から入射され、前記検査部位から伝達した超音波を前記受信探触子で受信する。
【００１２】
さらに、互いの表面が交差するように溶接された部材の溶接部を検査部位とし、
これら部材を溶接している溶接ビードの表面に、前記検査部位に向けて超音波を入射せしめる入射探触子を配置すると共に、前記部材のいずれか一方の部材の表面に、前記入射探触子が入射せしめた超音波を受信する受信探触子を配置し、前記入射探触子から前記溶接ビードの表面と所定の角度をなし、かつ、所定の広がり角の発信角で超音波を前記検査部位に向けて入射させ、前記受信探触子によって受信する前記検査部位から伝達された超音波の方向と前記部材とのなす角が、前記入射探触子が入射した超音波と前記溶接ビードの表面とがなす角度より小さな角度となるようにすると共に、前記受信探触子を基準とする広がり角である受信可能角が、前記発信角より小さな広がり角である受信可能角の範囲内に前記検査部位から伝達された超音波のみを受信する。上述の発明で不感帯が形成されることを防止することに加え、ビード表面から超音波を入射することで、より効率的に探傷を行うことができる。すなわち、溶接部に内在する欠陥部からの回折波は、部材の裏面から反射するエコー波より確実に先に受信探触子により受信される。このため、片側からの測定で欠陥の有無を判断することができる。
【００１３】
このようして超音波探傷を行うことで、検査対象の形状や探傷しようとする範囲の広さに適応した入射探触子及び受信探触子を適宜選択し、信頼性の高い超音波探傷を行うことができる。
【００１４】
【発明の実施の形態】
以下、本発明の実施の形態について図面を参照しながら説明する。
【００１５】
図１は、本発明の一実施形態にかかる超音波探傷装置を使用して、構造物を構成する２つの部材Ａ，Ｂの溶接部３０を探傷している様子を示している。この図１に示すように、溶接されている一方の部材は水平に延びる梁材Ａであり、他方の部材は、一端から他端に向けて末広がりに形成された斜面を有する台形状部材Ｂである。この実施形態では、超音波探傷装置を使用して、梁材Ａの軸方向の端面と台形状部材Ｂの上底面とが突き合わせ溶接されている溶接部３０の溶け込み不良を探傷している。
【００１６】
この超音波探傷装置は、検査対象である構造物に超音波を入射する入射探触子１と、この入射探触子１から入射され、構造物を伝達してきた超音波を受信する受信探触子１０とを備えている。入射探触子１は梁材Ａの上面に接触されている一方、受信探触子１０は、溶接部３０を入射探触子１と受信探触子１０との間に位置させて、台形状部材Ｂの傾斜面に接触されている。入射探触子１には、この入射探触子１に所定の電圧を印加して入射探触子１から超音波を発信させる発信機２０がケーブルを介して接続されている。一方、受信探触子１０には、この受信探触子１０が発信する、受信した超音波に対応した電気信号を受信する受信機２１がケーブルを介して接続されている。さらに、受信機２１には、受信機２１が受信した電気信号に対応する波形を映し出すモニタ装置２２が接続されている。
【００１７】
この超音波探傷装置では、入射探触子１から縦波の超音波を梁材Ａに入射させ、構造物の表面Ｃに沿って伝達するラテラル波、溶け込み不良３１の上端３２及び下端３３で発生する回折波、並びに梁材Ａの下面Ｄで反射するエコー波を、台形状部材Ｂに接触させている受信探触子１０で受信して、溶け込み不良３１の有無、位置、大きさを検査している。この超音波探傷装置では、入射探触子１が、内蔵された発信素子から所定の広がり角度の発信角αで超音波を梁材Ａに入射すると共に、受信探触子１０が、所定の広がり角を有する受信可能角βの範囲内に伝達されてきた超音波のみを受信するように構成されている。
【００１８】
入射探触子１は梁材Ａの上面に配置されるため、溶接部３０の全域に超音波を伝達させるには、入射探触子１から広い角度で超音波を発信させる必要がある。このため、この入射探触子１では、発信素子が超音波を比較的大きな発信角αで発信しており、溶接部３０の全範囲に漏れなく超音波を到達させている。これに対し、受信探触子１０は、溶接部３０に内在する欠陥のみを検査する必要がある。このため、受信探触子１０は、超音波を受信する範囲を溶接部３０の範囲のみに限定するように、受信可能角βが入射探触子１の発信角αより小さく設定されている。
【００１９】
また、入射探触子１は、その側方に位置する溶接部３０の全域に超音波を到達させる必要があるので、相対的に下方に向けて超音波を入射している。一方、受信探触子１０は、傾斜面に配置されているので、受信探触子１０と溶接部３０を結ぶ線と傾斜面とがなす角度は、入射探触子１と溶接部３０とを結ぶ線と梁材Ａの上面とがなす角より遙かに小さくなる。このため、この受信探触子１０は、接触させている傾斜面に、より近い方向から超音波を受信できるように、受信可能角βの設定される方向をより傾斜斜面側に大きく屈折させるように構成されている。
【００２０】
図２は、入射探触子１及び受信探触子１０の内部構造を示している。これら入射探触子１及び受信探触子１０は、その外殻をなす箱状のケーシング２，１１を有し、ケーシング２，１１の内部には、介在部材であるクサビ部材３，１２と、このクサビ部材３，１２の上面４，１３に取り付けられた発信素子６、受信素子１５が内蔵されている。ケーシング２，１１は、アルミニウム、銅、その他の導電金属によって、その上面が密閉され、下面が開放されるように形成されている。また、クサビ部材３，１２は、アクリル樹脂、ポリイミド樹脂等の樹脂で形成され、超音波を透過させている。クサビ部材３，１２の下面５，１４は検査対象の表面と密接に接触するように平坦にそれぞれ形成されている一方、その上面４，１３は、入射探触子１又は受信探触子１０の後部側が下側に向けて傾く傾斜面として形成されている。
【００２１】
入射探触子１に内蔵されたクサビ部材３の上面４は、水平線に対して形成される傾斜角θ１が比較的になだらかに形成されている一方で、受信探触子１０に内蔵されたクサビ部材１２の上面１３は、その傾斜角θ２が入射探触子１に比べ大きく形成されている。このため、受信素子１５の受信面１６は、発信素子６の発信面７に比べ前方に向けられている。
【００２２】
また、発信素子６及び受信素子１５は、水晶，圧電セラミックス材料等により形成されている。発信素子６は所定の軸方向に正負の電圧が印加されると伸縮により超音波を発生する逆圧電効果を奏する一方で、受信素子１５は、超音波を受信することで電圧を発生させる圧電効果を奏している。これらの作用によって、発信素子６は超音波を発生させ、また受信素子１５は電気信号を発信している。なお、受信素子１５の受信面１６の面積は、発信素子６の発信面７の面積より大きく形成されている。
【００２３】
以上のように入射探触子１及び受信探触子１０が構成されているので、超音波探傷装置は次のように作用する。
【００２４】
入射探触子１の超音波の発信方向及び受信探触子１０の受信方向は、各クサビ部材３，１２の上面４，１３の水平面に対する傾斜角θ１，θ２により設定される。傾斜角θ１，θ２が小さく形成されていれば検査対象の表面で超音波が屈折した場合、相対的に鉛直下方に向けて入射され、又は鉛直下方からの超音波を受信し、表面とのなす角度φ１，φ２が大きくなる。一方、上面４，１３の傾斜角θ１，θ２が大きく形成されていれば、検査対象の表面で超音波が屈折した際、相対的に表面により近い位置へ超音波を入射させ、又は表面により近い位置の超音波を受信でき、表面とのなす角度φ１，φ２が小さくなる。この超音波探傷装置では、入射探触子１に内蔵されたクサビ部材３の上面４の傾斜角θ１を小さく形成し、検査対象の表面とのなす角φ１を相対的に大きくして超音波を入射させている。一方、受信探触子１０に内蔵されたクサビ部材１２の上面１３の傾斜角θ２を大きく形成し、検査対象の表面とのなす角φ２が相対的に小さい方向からの超音波を取り込むようにしている。
【００２５】
また、入射探触子１の発信角αと受信探触子１０の受信可能角βとは、内蔵された発信素子６及び受信素子１５の大きさ、並びに超音波の波長により決定される。発信角α及び受信可能角βは、発信素子６及び受信素子１５が大きいほど小さくなり、超音波の波長が長いほど大きくなる。この超音波探傷装置では、入射探触子１が発した超音波を受信探触子１０で受信するため、超音波の波長によって入射探触子１と受信探触子１０の広がり角に差を設けることはできない。このため、入射探触子１に発信面７の面積の小さな発信素子６を内蔵させる一方で、受信探触子１０に、発信面７の面積より大きく形成された受信面１６を有する受信素子１５を内蔵させている。
【００２６】
このような入射探触子１と受信探触子１０との組み合わせにより、梁材Ａと台形状部材Ｂとの溶接部３０の欠陥は以下のようにして探傷される。
【００２７】
入射探触子１を溶接部３０の側方にて梁材Ａの上面に接触させる。この際、入射探触子１の先端側を溶接部３０に向けて配置する。一方、受信探触子１０を台形状部材Ｂの傾斜面に接触させる。受信探触子１０についてもその先端側を溶接部３０に向けて配置する。
【００２８】
両探触子１，１０をこのように配置した状態で、発信機２０を作動から入射探触子１に所定の電圧を印加して、内蔵された発信素子６から超音波を発信させる。この発信素子６は、受信素子１５に比し小さく形成されているため、この発信素子６からは、相対的に大きな発信角αの超音波が発信される。また、傾斜角θ１の小さく形成された上面４を有するクサビ部材３の上面に発信素子６が取り付けられているので、梁材Ａの表面となす角φ１が相対的に大きな方向に向けて超音波は入射される。これにより、溶接部３０の全域に超音波を伝達させることができる。
【００２９】
そして、受信探触子１０で、構造物の表面Ｃを伝達するラテラル波、溶け込み不良３１の上端３２で発生する回折波、溶け込み不良３１の下端３３で発生する回折波、並びに梁材Ａの下面Ｄで反射されるエコー波を受信する。上述のように、受信探触子１０に内蔵された受信素子１５は、傾斜角θ２の大きく形成された上面１３を有するクサビ部材１２に取り付けられて、受信面１６が受信探触子１０の前方へ向けられている。また、受信面１６の面積が発信面７の面積に比し、大きく形成されている。このため、受信探触子１０は、斜面部とのなす角φ２が小さい表面に近い方向で、しかも受信可能角βが小さい範囲の超音波のみを受信する。これにより、溶接部３０からの超音波のみを受信し、溶接部３０以外で発生する回折波やエコー波を取り込むことがない。
【００３０】
受信探触子１０で受信したラテラル波、回折波及びエコー波は受信素子１５で電気信号に変化され、受信機２１に送信される。この電気信号を受信した受信機２１は、この信号に対して所定の変換を行って、その下流に接続されたモニタ装置２２に送信し、対応する超音波の波形を映し出させている。
【００３１】
図３は、モニタ装置２２に映し出された波形を示している。図３の最も左側に現れている波形４０は、ラテラル波によるもので、左から２番目に現れている波形４１は、溶け込み不良３１の上端３２で発生した回折波によるものである。溶け込み不良３１の上端３２で発生した回折波による波形４１の右側直近に現れている波形４２は、溶け込み不良３１の下端３３で発生した回折波に対応している。そして、右端に現れている波形４３は、梁材Ａの下面Ｄで反射したエコー波に対応する波形である。このグラフにおいて、ラテラル波に対応する波形４０と、溶け込み不良３１の上端３２で発生した回折波に対応する波形４１の間隔５０は、梁材Ａの上面から溶け込み不良３１の上端３２までの深さを表している。また、２つの回折波に対応する波形４１，４２同士の間隔５１は、溶け込み不良３１の長さを表している。そして、溶け込み不良３１の下端３３で発生した回折波に対応する波形４２と、エコー波に対応する波形４３との間隔５２は溶け込み不良３１の下端３３から梁材Ａの下面Ｄまでの距離を表している。このように、当該超音波探傷装置を使用すれば、単に溶接部３０に欠陥があるか否かを検査するだけで無く、欠陥の位置と大きさをも特定することができる。図１に示す例であれば、溶け込み不良３１の長さＬ、梁材Ａの上面から溶け込み不良３１の上端３２までの距離Ｌ１、下端３３までの距離Ｌ２を正確に把握することができる。
【００３２】
図４は、この超音波探傷装置を使用して、他の構造物の溶接部を探傷している実施形態を示している。
【００３３】
この実施形態における検査対象である構造物は、鉛直に延びる平板Ｅの一面側に、水平に延びる他の平板Ｆの端面を突き合わせ、両部材Ｅ，Ｆが直角をなすようにして溶接された構造物である。この実施形態では、入射探触子６０を水平に配された平板Ｆの下面に接触させると共に、受信探触子６１を鉛直に延びる平板Ｅの一面側であって、水平に延びる平板Ｆの下方に接触させている。なお、この場合も入射探触子６０の先端を溶接部６５側へ向けて接触させると共に、受信探触子６１の先端も溶接部６５側へ向けて接触させる。
【００３４】
かかる構造物を探傷する場合に関しても、入射探触子６０から相対的に大きな発信角α２で超音波を構造物水平に延びる平板Ｆに入射させる一方、受信探触子６１は、発信角α２に比べて小さな受信可能角β２の範囲内で超音波を受信している。また、入射探触子６０から水平に延びる平板Ｆへは、接触させた下面とのなす角φ３が相対的に大きくなる方向へ超音波が入射される一方で、受信探触子６１へは、水平に延びる平板との接合面である一面側とのなす角φ４が小さく相対的にその表面に近い方向からの超音波を受信する。
【００３５】
なお、この実施形態にかかる構造物を探傷する場合、図１と図４との比較から明らかなように、受信探触子６１は、垂直に延びる平板Ｅの表面により近い方向から超音波を受信すると共に、受信可能角β２をより小さく形成しなければ、溶接部６５のみから超音波を受信することができなくなる。このため、この受信探触子６１では内蔵されたクサビ部材（不図示）の上面の傾斜角が、図１に示す受信探触子１０に内蔵されクサビ部材１２の上面１３の傾斜角より大きく形成され、受信面がより前方に大きく傾くように構成されている。また、受信可能角β２をより小さく形成するために、この受信探触子６１では、受信素子（不図示）の受信面の面積が、図１に示す受信探触子１０の受信面の面積より大きく形成されている。
【００３６】
なお、この実施形態では、受信探触子６１についてのみ、受信可能角β２、検査対象の表面とのなす角φ４が異なる探触子を選択したが、検査対象によっては、入射探触子６０を適宜選択し、又は入射探触子及び、受信探触子６１の双方を選択して使用してもよい。この際、発信角と受信可能角のみ、あるいは超音波を入射させる方向と受信する方向の双方のみが異なる探触子を選択してもよく、これらのいずれもが異なる探触子を選択してもよい。
【００３７】
このように、この超音波探傷装置では、互いに異なる発信角で、異なる方向に超音波を発信する入射探触子と、互いに異なる受信可能角で、異なる方向から超音波を受信する受信探触子をそれぞれ複数備えている。かかる入射探触子及び受信探触子の中から、検査対象に最も適した超音波を入射させる入射探触子及び超音波を受信する受信探触子を適宜選択して超音波探傷が行われる。
【００３８】
図５は、本発明の別の実施形態にかかる方法で、検査対象の超音波探傷を行う態様を示している。この実施の形態にかかる探傷方法では、部材同士が互いに直角に交差された状態で溶接された溶接部を検査対象としている。垂直に配置された縦板７０の一面側には、水平に配された横板７１の端面が溶接されている。これら両板材７０，７１の溶接部が検査対象である。この探傷方法では、入射探触子７２を横板７１の上側に位置する溶接ビード７５の表面に接触させ、溶接ビード７５から超音波を入射させている一方、受信探触子７３を横板７１の上方にて縦板７０の表面に接触させて、縦板７０を伝達した超音波を受信している。この実施形態においても、検査対象の表面である溶接ビード７５の表面と入射探触子７２から入射された超音波のなす角より、受信探触子７３により受信される超音波の方向と検査対象の表面がなす角が小さくなる探触子同士が組み合わせされている。
【００３９】
そして、この探傷方法に関しても、溶接ビード７５の表面及び縦板７０の表面を伝達するラテラル波、欠陥７７の上端で回折された回折波、欠陥７７の下端で回折された回折波（図５中、二点鎖線で示した矢印）、及び横板の下面で反射されたエコー波（図５中、実線で示した矢印）を解析して欠陥７７の位置及び長さが特定される。ここで、入射探触子７２は溶け込み不良等の欠陥７７と比較的接近した位置である溶接ビード７５の表面に接触されており、溶け込み不良等の欠陥７７と入射探触子７２との距離は、入射探触子と横板の下面との距離に比し相対的に短い。このため、欠陥７７の下端を回折する回折波が、横板の下面を反射するエコー波より先に受信され、図６に示すように、モニタには回折波８０がエコー波８１より確実に先に現れる。したがって、横板の上側からのみ探傷を行えば、欠陥７７の探傷を行うことができる。
【００４０】
このメリットに関し、図７及び図８に示す探傷方法と対比して説明する。
【００４１】
図７に示す探傷方法も、直角に交わるように縦板９０の片面に横板９１の端面を突き合わせて溶接した溶接部を探傷している。この探傷方法にあっては、入射探触子９２が溶接部からやや離れた位置にて横板９１の上面に接触されており、欠陥９７と入射探触子９２との距離が比較的離れている。このように配置された状態では、内在する欠陥９７が大きくその長さが長い場合、入射探触子９２−横板９１の下面−受信探触子９３の経路の距離（図７の実線で示した矢印）より、入射探触子９２−欠陥９７の下端−受信探触子９３の経路（図７の二点鎖線で示した矢印）の距離の方が長くなることもある。この場合、エコー波の方が回折波より先に受信探触子に受信される。このため、モニタには、図８に示すように、エコー波１００が回折波１０１より先に表示される。このような波形が測定されることがあると、波形１００，１０１のどの部分がエコー波１００で、どの部分が回折波１０１であるのか不明となり、正確な解析を行うことができない。
【００４２】
このため、横板９１の下側からの探傷も必要となる。すなわち、入射探触子９２を横板９１の下面に接触させると共に、この横板９１よりやや下方の位置にて、受信探触子９３を縦板９０の片面に接触させて、再び探傷を行う。そして、上側からの探傷において、モニタの画面の３番目に現れる波形及び４番目に現れる波形、並びに下側からの探傷において、モニタの画面の第２番目に現れる波形を総合的に分析することで、欠陥の位置、大きさを特定する。
【００４３】
このように、図７に示す探傷方法では、欠陥を特定するのに手間と時間を要するが、図５に示すように入射探触子７２を溶接ビード７５の表面に接触させて、溶接ビード７５の表面から超音波を入射させて探傷を行うことで、片側からの探傷のみで欠陥の位置大きさを正確に把握することができる。
【００４４】
なお、図５では、二つの部材が直角をなして溶接された溶接部を探傷する様子を示しているが、二つの部材が所定の角度をなして交差していれば、部材同士がなす角度は直角をなすものには限定されない。
【００４５】
【発明の効果】
以上、本発明によれば、超音波を入射させる方向及び発信角、並びに超音波を受信する方向と受信可能角を所定の範囲に特定しているので、平面形状の検査対象に限定されることなく複雑な形状を有する構造物について、きわめて容易に超音波探傷することができる。また、入射探触子及び受信探触子を検査対象に適応させて適宜選択可能としているので、種々の形状の構造物について超音波探傷を行える。
【００４６】
特に、所定の角度で交わる部材同士の溶接部を探傷する場合に、入射探触子を溶接ビードの表面に接触させて、超音波をこの溶接ビードの表面から入射すれば、一度の探傷で欠陥の位置大きさを正確に把握することができる。
【図面の簡単な説明】
【図１】本発明の一実施形態にかかる超音波探傷装置を使用して構造物を探傷している一態様を示す図。
【図２】図１に示す超音波探傷装置に使用されている入射探触子及び受信探触子の内部構造を示す図。
【図３】図１に示す超音波探傷装置のモニタ装置に現れる波形の説明図。
【図４】図１に示す構造物とは別の構造物について超音波探傷を行う態様を示す図。
【図５】本発明の別の実施形態にかかる超音波探傷方法の態様を示す図。
【図６】図５に示す超音波探傷方法で探傷を行った場合のモニタに現れる波形の説明図。
【図７】図５に示す超音波探傷と別の態様で超音波探傷を行う態様を示す図。
【図８】図７に示す超音波探傷方法で探傷を行った場合のモニタに現れる波形の説明図。
【図９】従来から行われているＴＯＦＤ法で超音波探傷を行う態様を示す図。
【図１０】図９に示すＴＯＦＤ法で超音波探傷を行った場合のモニタに現れる波形の説明図。
【符号の説明】
１，６０，７２，９２入射探触子
２，１１ケーシング
３，１２クサビ部材
４，１３上面
６発信素子
７発信面
１０，６０，７３，９３受信探触子
１５受信素子
１６受信面
２０発信機
２１受信機
２２モニタ装置
３０，６５溶接部（検査部位）
α，α２発信角
β，β２受信可能角
θ１，θ２傾斜角
φ１，φ３超音波が入射された方向と検査対象の表面がなす角
φ２，φ４受信される超音波の方向と検査対象の表面がなす角[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method in which an ultrasonic wave is incident on an inspection object with an incident probe, and an ultrasonic wave transmitted through the inspection object is received with a reception probe.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a TOFD (Time Of Flight Diffraction) method is known as ultrasonic flaw detection for inspecting a defect inherent in an inspection target without destroying the inspection target. In the TOFD method, as shown in FIG. 9, an incident probe 110 that makes an ultrasonic wave incident on an inspection object and a reception probe 111 that receives the ultrasonic wave face each other and contact the surface of the inspection object 112. A longitudinal wave ultrasonic wave is incident on the inspection object 112 from the incident probe 110 and is generated at the upper end 114 and the lower end 115 of the inherent defect 113. Diffraction wave Is received by the reception probe 111, and the defect 113 is detected. In such a TOFD method, a lateral wave propagating along the surface of the inspection object 112 is generated at the upper end 114 and the lower end 115 of the defect 113. Diffraction wave 121,122 In addition, the position and size of the defect can be accurately inspected based on the relationship between the time difference of the echo wave 123 reflected from the bottom surface of the inspection object 112 and the sound velocity from the incident probe 110 to the reception probe 111. .
[0003]
In particular, FIG. As shown in the figure, a lateral wave 120 is generated at the upper end of the defect on the monitor device that can display a waveform such as an oscilloscope. Diffraction wave 121 Occurs at the bottom of the defect Diffraction wave 122 , And the echo wave 123 is displayed. Then, the position of the defect and the size of the defect are specified by analyzing the propagation time of each waveform.
[0004]
A plurality of prior arts have already been disclosed for such a non-destructive inspection method using the TOFD method (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
JP 2002-139479 A (paragraph numbers 0012 to 0013, FIG. 1, paragraph number 0003, FIG. 6).
[0006]
[Problems to be solved by the invention]
However, this TOFD method requires that the inspection target is formed in a planar shape, and that both the incident probe and the receiving probe are arranged on the same plane. For this reason, it is impossible to detect internal defects by a TOFD method for a structure having a complicated shape such as a bridge girder. In recent years, a new non-destructive inspection method capable of inspecting a structure having a complicated shape such as a bridge girder without destroying an inspection object is socially desired.
[0007]
The present invention has been made in order to meet such a demand, and an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method capable of flaw detection of existing defects without destroying an inspection object having a complicated shape. The purpose is to provide.
[0008]
[Means for Solving the Problems]
In the present invention, in order to solve the above problems, So that the surfaces of each other intersect In an ultrasonic flaw detector using a bonded portion of a bonded member as an inspection site, an incident probe arranged on the surface of one of the bonded members and allowing ultrasonic waves to enter the inspection site, and the other member A receiving probe that receives the ultrasonic wave incident by the incident probe, and the incident probe includes a line connecting to the inspection site and a surface of one of the members. Are arranged so as to form a predetermined inclination angle. In addition, The receiving probe is connected to the line to be inspected and The other The incident probe is arranged so as to form a predetermined inclination angle, and the incident probe has a transmitting surface directed toward the inspection site, and transmits a predetermined spread angle from a transmitting element that transmits ultrasonic waves. An ultrasonic wave is incident on the examination site at a corner, and the reception probe has a reception surface directed toward the examination site side, and is input from the incidence probe and transmitted to the examination site. A receiving element for receiving a sound wave is built in, and only an ultrasonic wave within a receivable angle that is a predetermined spread angle is received, and an inclination angle formed between the receiving surface and the surface of the other member is set to one side of the transmitting surface. The receiving surface is formed to be larger than the angle of inclination formed with the surface of the member, and the receiving surface is relatively inclined to the inspection site side relative to the transmitting surface, and the receivable angle is smaller than the transmitting angle. Adopted the formed ultrasonic flaw detector
[0009]
Also, So that the surfaces of each other intersect The joining portion of the joined member is used as an inspection site, and an incident probe that allows ultrasonic waves to enter the inspection site is disposed on the surface of one of the joined members, and the incident on the surface of the other member. A receiving probe that receives ultrasonic waves incident on the probe is disposed, and a predetermined angle is formed with the surface of one of the members from the incident probe, and the transmission angle is a predetermined spread angle. A sound wave is incident on the inspection site, and the receiving probe Before receiving Ultrasound transmitted from the test site Direction The angle formed by the other member is smaller than the angle formed by the ultrasonic wave incident on the incident probe and the surface of the one member. And the above The receivable angle, which is a spread angle with respect to the reception probe, is smaller than the transmission angle. Of the receivable angle which is the spread angle The inspection object is flawed by an ultrasonic flaw detection method characterized by receiving only the ultrasonic waves transmitted from the inspection region within the range.
[0010]
According to the present invention, from the incident probe Inspection site Ultrasonic waves are incident on a relatively wide area, and the ultrasonic waves reach the site to be flawed without leakage. On the other hand, the receiving probe made contact The other member Only ultrasonic waves in a direction relatively close to the surface and within a smaller angle range are received. This For inspection objects with complex shapes , Incident from the incident probe, Inspection site The receiving probe reliably receives the ultrasonic wave transmitted. In addition, since the receiving probe receives only the ultrasonic waves transmitted from a limited range to be flawed, extra echo waves and Diffraction wave To achieve high reliability.
[0011]
One of the members Surface of And the other member Surface In accordance with the angle formed, at least one of the angle formed with the surface of the member or the transmission angle is changed and ultrasonic waves are incident from the incident probe, and one of the members Surface of And the other member Surface In accordance with the angle formed, at least one of the angle formed with the surface of the other member or the receivable angle is changed, and the ultrasonic wave incident from the incident probe and transmitted from the inspection site is transmitted. Receive with the receiving probe.
[0012]
further, So that the surfaces of each other intersect The welded part of the welded member is used as the inspection site,
An incident probe that allows ultrasonic waves to be incident on the inspection site is disposed on the surface of a weld bead that welds these members, and the incident probe is disposed on the surface of one of the members. A receiving probe for receiving ultrasonic waves incident on the surface of the welding bead, forming a predetermined angle with the surface of the weld bead from the incident probe, and detecting the ultrasonic waves at a transmission angle of a predetermined spread angle. Incident on the part, and by the receiving probe Before receiving Ultrasound transmitted from the test site Direction The angle formed by the member and the member is smaller than the angle formed by the ultrasonic wave incident on the incident probe and the surface of the weld bead. And before The receivable angle, which is a spread angle based on the receiving probe, is smaller than the transmission angle. Of the receivable angle which is the spread angle Only the ultrasonic waves transmitted from the examination site within the range are received. In addition to preventing the formation of dead zones in the above-described invention, flaw detection can be performed more efficiently by making ultrasonic waves incident from the bead surface. That is, the diffracted wave from the defective part existing in the welded part is reliably received by the receiving probe before the echo wave reflected from the back surface of the member. For this reason, the presence or absence of a defect can be determined by measurement from one side.
[0013]
By performing ultrasonic flaw detection in this way, an incident probe and a reception probe that are suitable for the shape of the inspection target and the size of the range to be flaw-detected are appropriately selected to perform highly reliable ultrasonic flaw detection. It can be carried out.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 shows a state where a welded portion 30 of two members A and B constituting a structure is flawed using an ultrasonic flaw detector according to an embodiment of the present invention. As shown in FIG. 1, one member that is welded is a beam member A that extends horizontally, and the other member is a trapezoidal member B that has an inclined surface that extends from one end to the other end. is there. In this embodiment, an ultrasonic flaw detector is used to detect flaws in the welded portion 30 in which the end face in the axial direction of the beam A and the upper bottom surface of the trapezoidal member B are butt welded.
[0016]
The ultrasonic flaw detection apparatus includes an incident probe 1 that makes an ultrasonic wave incident on a structure to be inspected, and a reception probe that receives the ultrasonic wave that has been incident from the incident probe 1 and transmitted through the structure. The child 10 is provided. While the incident probe 1 is in contact with the upper surface of the beam A, the receiving probe 10 has a trapezoidal shape with the welded portion 30 positioned between the incident probe 1 and the receiving probe 10. The inclined surface of the member B is contacted. A transmitter 20 is connected to the incident probe 1 via a cable to apply a predetermined voltage to the incident probe 1 to transmit ultrasonic waves from the incident probe 1. On the other hand, a receiver 21 that receives an electrical signal corresponding to the received ultrasonic wave transmitted from the receiving probe 10 is connected to the receiving probe 10 via a cable. Furthermore, a monitor device 22 that displays a waveform corresponding to the electrical signal received by the receiver 21 is connected to the receiver 21.
[0017]
In this ultrasonic flaw detector, a longitudinal wave is incident on the beam A from the incident probe 1 and is transmitted along the surface C of the structure, and is generated at the upper end 32 and the lower end 33 of the poor penetration 31. Do Diffraction wave The echo wave reflected from the lower surface D of the beam A is received by the receiving probe 10 in contact with the trapezoidal member B, and the presence, position, and size of the penetration defect 31 are inspected. In this ultrasonic flaw detector, the incident probe 1 makes an ultrasonic wave incident on the beam A at a transmission angle α having a predetermined spread angle from a built-in transmission element, and the reception probe 10 has a predetermined spread. Only the ultrasonic wave transmitted within the range of the receivable angle β having an angle is received.
[0018]
Since the incident probe 1 is disposed on the upper surface of the beam A, it is necessary to transmit ultrasonic waves from the incident probe 1 at a wide angle in order to transmit ultrasonic waves to the entire area of the welded portion 30. For this reason, in this incident probe 1, the transmitting element transmits ultrasonic waves at a relatively large transmission angle α, and the ultrasonic waves reach the entire range of the welded portion 30 without leaking. On the other hand, the receiving probe 10 needs to inspect only the defects inherent in the welded portion 30. For this reason, the reception probe 10 is set so that the receivable angle β is smaller than the transmission angle α of the incident probe 1 so as to limit the ultrasonic wave reception range to the range of the welded portion 30.
[0019]
Moreover, since it is necessary for the incident probe 1 to reach the entire area of the welded portion 30 located on the side of the incident probe 1, the ultrasonic wave is incident relatively downward. On the other hand, since the receiving probe 10 is arranged on an inclined surface, the angle formed between the line connecting the receiving probe 10 and the welded portion 30 and the inclined surface is determined by the incident probe 1 and the welded portion 30. It is much smaller than the angle formed by the connecting line and the upper surface of the beam A. For this reason, the receiving probe 10 refracts the direction in which the receivable angle β is set to the inclined slope side so that the ultrasonic wave can be received from a direction closer to the inclined surface that is in contact. It is configured.
[0020]
FIG. 2 shows the internal structure of the incident probe 1 and the receiving probe 10. The incident probe 1 and the receiving probe 10 have box-shaped casings 2 and 11 that form outer shells thereof, and inside the casings 2 and 11 are wedge members 3 and 12 that are interposed members, The transmitting element 6 and the receiving element 15 attached to the upper surfaces 4 and 13 of the wedge members 3 and 12 are incorporated. The casings 2 and 11 are formed so that the upper surface is sealed and the lower surface is opened with aluminum, copper, or other conductive metal. The wedge members 3 and 12 are made of resin such as acrylic resin or polyimide resin, and transmit ultrasonic waves. The lower surfaces 5 and 14 of the wedge members 3 and 12 are formed flat so as to be in close contact with the surface to be inspected, while the upper surfaces 4 and 13 are formed on the incident probe 1 or the receiving probe 10. The rear portion side is formed as an inclined surface inclined toward the lower side.
[0021]
The upper surface 4 of the wedge member 3 incorporated in the incident probe 1 has a relatively gentle inclination angle θ1 formed with respect to the horizontal line, while the wedge incorporated in the reception probe 10. The upper surface 13 of the member 12 is formed with a larger inclination angle θ2 than the incident probe 1. For this reason, the receiving surface 16 of the receiving element 15 is directed forward relative to the transmitting surface 7 of the transmitting element 6.
[0022]
The transmitting element 6 and the receiving element 15 are made of quartz, a piezoelectric ceramic material, or the like. The transmitting element 6 exhibits an inverse piezoelectric effect that generates ultrasonic waves by expansion and contraction when positive and negative voltages are applied in a predetermined axial direction, while the receiving element 15 generates a voltage by receiving ultrasonic waves. I play. By these actions, the transmitting element 6 generates ultrasonic waves, and the receiving element 15 transmits electric signals. The area of the receiving surface 16 of the receiving element 15 is formed larger than the area of the transmitting surface 7 of the transmitting element 6.
[0023]
Since the incident probe 1 and the reception probe 10 are configured as described above, the ultrasonic flaw detector operates as follows.
[0024]
The ultrasonic wave transmission direction of the incident probe 1 and the reception direction of the reception probe 10 are set by inclination angles θ1 and θ2 of the upper surfaces 4 and 13 of the wedge members 3 and 12 with respect to the horizontal plane. If the inclination angles θ1 and θ2 are formed small, when the ultrasonic wave is refracted on the surface to be inspected, it is incident relatively vertically downward or receives the ultrasonic wave from vertically below and forms with the surface. Angles φ1 and φ2 increase. On the other hand, if the inclination angles θ1 and θ2 of the upper surfaces 4 and 13 are formed large, when the ultrasonic waves are refracted on the surface to be inspected, the ultrasonic waves are incident on a position relatively closer to the surface or closer to the surface. The ultrasonic waves at the position can be received, and the angles φ1 and φ2 made with the surface become small. In this ultrasonic flaw detector, the inclination angle θ1 of the upper surface 4 of the wedge member 3 built in the incident probe 1 is formed to be small, and the angle φ1 formed with the surface to be inspected is relatively increased to generate ultrasonic waves. Incident. On the other hand, the inclination angle θ2 of the upper surface 13 of the wedge member 12 incorporated in the reception probe 10 is formed large, and ultrasonic waves from a direction where the angle φ2 formed with the surface of the inspection object is relatively small are captured. Yes.
[0025]
The transmission angle α of the incident probe 1 and the receivable angle β of the reception probe 10 are determined by the sizes of the built-in transmission element 6 and reception element 15 and the wavelength of the ultrasonic wave. The transmission angle α and the receivable angle β decrease as the transmission element 6 and the reception element 15 increase, and increase as the wavelength of the ultrasonic wave increases. In this ultrasonic flaw detector, since the ultrasonic wave emitted from the incident probe 1 is received by the reception probe 10, the difference in the spread angle between the incident probe 1 and the reception probe 10 is varied depending on the wavelength of the ultrasonic wave. It cannot be provided. For this reason, while the transmitting element 6 having a small area of the transmitting surface 7 is built in the incident probe 1, the receiving element 15 having the receiving surface 16 formed larger than the area of the transmitting surface 7 in the receiving probe 10. Is built in.
[0026]
By such a combination of the incident probe 1 and the receiving probe 10, defects in the welded portion 30 between the beam member A and the trapezoidal member B are detected as follows.
[0027]
The incident probe 1 is brought into contact with the upper surface of the beam A at the side of the welded portion 30. At this time, the distal end side of the incident probe 1 is arranged toward the welded portion 30. On the other hand, the receiving probe 10 is brought into contact with the inclined surface of the trapezoidal member B. The receiving probe 10 is also arranged with its tip side facing the welded portion 30.
[0028]
In a state where both the probes 1 and 10 are arranged in this way, a predetermined voltage is applied to the incident probe 1 from the operation of the transmitter 20 to transmit ultrasonic waves from the built-in transmitter element 6. Since the transmitting element 6 is formed smaller than the receiving element 15, an ultrasonic wave having a relatively large transmitting angle α is transmitted from the transmitting element 6. Further, since the transmitting element 6 is attached to the upper surface of the wedge member 3 having the upper surface 4 formed with a small inclination angle θ1, the ultrasonic wave is directed toward the direction in which the angle φ1 formed with the surface of the beam A is relatively large. Is incident. Thereby, ultrasonic waves can be transmitted to the entire area of the welded portion 30.
[0029]
Then, in the receiving probe 10, a lateral wave that transmits the surface C of the structure is generated at the upper end 32 of the poor penetration 31. Diffraction wave Occurs at the lower end 33 of the poor penetration 31 Diffraction wave The echo wave reflected by the lower surface D of the beam material A is received. As described above, the receiving element 15 incorporated in the receiving probe 10 is attached to the wedge member 12 having the upper surface 13 formed with a large inclination angle θ2, and the receiving surface 16 is in front of the receiving probe 10. Is directed to. Further, the area of the receiving surface 16 is formed larger than the area of the transmitting surface 7. For this reason, the receiving probe 10 receives only the ultrasonic waves in the direction close to the surface where the angle φ2 formed with the inclined surface portion is small and the receivable angle β is small. As a result, only the ultrasonic waves from the welded portion 30 are received and generated outside the welded portion 30. Diffraction wave And does not capture echo waves.
[0030]
Lateral waves received by the receiving probe 10, Diffraction wave The echo wave is converted into an electrical signal by the receiving element 15 and transmitted to the receiver 21. The receiver 21 that has received the electrical signal performs predetermined conversion on the signal and transmits the signal to the monitor device 22 connected downstream thereof to display a corresponding ultrasonic waveform.
[0031]
FIG. 3 shows a waveform projected on the monitor device 22. The waveform 40 appearing on the leftmost side in FIG. 3 is due to a lateral wave, and the waveform 41 appearing second from the left is generated at the upper end 32 of the poor penetration 31. Diffraction wave Is due to. Occurred at the upper end 32 of the poor penetration 31 Diffraction wave The waveform 42 that appears immediately on the right side of the waveform 41 is generated at the lower end 33 of the poor penetration 31. Diffraction wave It corresponds to. The waveform 43 appearing at the right end is a waveform corresponding to the echo wave reflected by the lower surface D of the beam A. In this graph, the waveform 40 corresponding to the lateral wave and the upper end 32 of the poor penetration 31 occurred. Diffraction wave The interval 50 of the waveform 41 corresponding to 表し represents the depth from the upper surface of the beam A to the upper end 32 of the poor penetration 31. Also two Diffraction wave An interval 51 between the waveforms 41, 42 corresponding to 1 represents the length of the penetration defect 31. And it occurred at the lower end 33 of the poor penetration 31 Diffraction wave And a waveform 43 corresponding to an echo wave. The interval 52 is The distance from the lower end 33 of the poor penetration 31 to the lower surface D of the beam material A is shown. Thus, if the ultrasonic flaw detector is used, it is possible not only to inspect whether or not the welded portion 30 has a defect, but also to specify the position and size of the defect. In the example shown in FIG. 1, the length L of the penetration defect 31, the distance L 1 from the upper surface of the beam A to the upper end 32 of the penetration defect 31, and the distance L 2 to the lower end 33 can be accurately grasped.
[0032]
FIG. 4 shows an embodiment in which this ultrasonic flaw detector is used to flaw welds in other structures.
[0033]
The structure to be inspected in this embodiment has a structure in which the end surface of another horizontally extending flat plate F is abutted against one surface side of a vertically extending flat plate E and welded so that both members E and F form a right angle. It is a thing. In this embodiment, the incident probe 60 is brought into contact with the lower surface of the horizontally arranged flat plate F, and the receiving probe 61 is on one surface side of the vertically extending flat plate E and below the horizontally extending flat plate F. Is in contact with In this case as well, the tip of the incident probe 60 is brought into contact with the welded portion 65 side, and the tip of the receiving probe 61 is also brought into contact with the welded portion 65 side.
[0034]
Also when flaw detection is performed on such a structure, ultrasonic waves are incident on the flat plate F extending horizontally from the structure at a relatively large transmission angle α2 from the incident probe 60, while the reception probe 61 is at the transmission angle α2. The ultrasonic waves are received within a range of a receivable angle β2 that is smaller than that. In addition, an ultrasonic wave is incident on the flat plate F extending horizontally from the incident probe 60 in a direction in which the angle φ3 formed with the lower surface in contact with the flat surface F becomes relatively large. An ultrasonic wave is received from a direction relatively close to the surface with a small angle φ4 formed with one surface side which is a joint surface with a horizontally extending flat plate.
[0035]
When flaw detection is performed on the structure according to this embodiment, the receiving probe 61 receives ultrasonic waves from a direction closer to the surface of the vertically extending flat plate E, as is apparent from a comparison between FIG. 1 and FIG. In addition, unless the receivable angle β2 is made smaller, it is impossible to receive ultrasonic waves only from the welded portion 65. Therefore, in the receiving probe 61, the inclination angle of the upper surface of the wedge member (not shown) built in is larger than the inclination angle of the upper surface 13 of the wedge member 12 incorporated in the receiving probe 10 shown in FIG. The reception surface is configured to be greatly inclined forward. Further, in order to make the receivable angle β2 smaller, in this reception probe 61, the area of the reception surface of the reception element (not shown) is larger than the area of the reception surface of the reception probe 10 shown in FIG. Largely formed.
[0036]
In this embodiment, a probe having a receivable angle β2 and an angle φ4 formed with the surface to be inspected is selected only for the reception probe 61. However, depending on the inspection object, the incident probe 60 may be changed. You may select suitably, or you may select and use both the incident probe and the receiving probe 61. FIG. At this time, it is possible to select a probe that differs only in the transmission angle and the receivable angle, or only in the direction in which the ultrasonic wave is incident and the direction in which the ultrasonic wave is incident. Also good.
[0037]
Thus, in this ultrasonic flaw detector, an incident probe that transmits ultrasonic waves in different directions at different transmission angles and a reception probe that receives ultrasonic waves from different directions at different receivable angles. There are a plurality of each. Ultrasonic flaw detection is performed by appropriately selecting an incident probe for receiving an ultrasonic wave most suitable for an inspection target and a receiving probe for receiving the ultrasonic wave from among the incident probe and the receiving probe. .
[0038]
FIG. 5 shows a mode in which ultrasonic inspection of an inspection object is performed by the method according to another embodiment of the present invention. In the flaw detection method according to this embodiment, a welded portion welded in a state where members are crossed at right angles to each other is an inspection target. On one surface side of the vertical plate 70 arranged vertically, the end surface of the horizontal plate 71 arranged horizontally is welded. The welded portion of both plate members 70 and 71 is an inspection target. In this flaw detection method, the incident probe 72 is brought into contact with the surface of the weld bead 75 located on the upper side of the horizontal plate 71 and ultrasonic waves are incident from the weld bead 75, while the reception probe 73 is moved to the horizontal plate 71. The ultrasonic waves transmitted through the vertical plate 70 are received in contact with the surface of the vertical plate 70 above. Also in this embodiment, the direction of the ultrasonic wave received by the receiving probe 73 and the inspection target are determined from the angle formed by the surface of the weld bead 75 that is the surface of the inspection target and the ultrasonic wave incident from the incident probe 72. Probes with a small angle formed by the surface of each other are combined.
[0039]
In this flaw detection method as well, the lateral wave that transmits the surface of the weld bead 75 and the surface of the vertical plate 70, the upper end of the defect 77, diffraction Was Diffraction wave At the bottom of the defect 77 diffraction Was Diffraction wave (The arrow shown by the two-dot chain line in FIG. 5) and the echo wave reflected by the lower surface of the horizontal plate (the arrow shown by the solid line in FIG. 5) are analyzed to identify the position and length of the defect 77. The Here, the incident probe 72 is in contact with the surface of the weld bead 75 at a position relatively close to a defect 77 such as a poor penetration, and the distance between the defect 77 such as a poor penetration and the incident probe 72 is The distance is relatively shorter than the distance between the incident probe and the lower surface of the horizontal plate. For this reason, the lower end of the defect 77 is diffraction Do Diffraction wave Is received prior to the echo wave reflected from the lower surface of the horizontal plate, as shown in FIG. Diffraction wave 80 Appears reliably before the echo wave 81. Therefore, if the flaw detection is performed only from the upper side of the horizontal plate, the flaw 77 can be detected.
[0040]
This advantage will be described in comparison with the flaw detection method shown in FIGS.
[0041]
In the flaw detection method shown in FIG. 7 as well, a welded portion in which the end surface of the horizontal plate 91 is butted against one side of the vertical plate 90 so as to intersect at right angles is welded. In this flaw detection method, the incident probe 92 is in contact with the upper surface of the horizontal plate 91 at a position slightly away from the weld, and the distance between the defect 97 and the incident probe 92 is relatively large. Yes. In this arrangement, when the existing defect 97 is large and its length is long, the distance between the incident probe 92-the lower surface of the horizontal plate 91 and the path of the reception probe 93 (shown by the solid line in FIG. 7). The distance of the path of the incident probe 92 -the lower end of the defect 97 -the path of the reception probe 93 (the arrow indicated by the two-dot chain line in FIG. 7) may be longer than the arrow). In this case, the echo wave is better Diffraction wave It is received by the receiving probe earlier. Therefore, the echo wave 100 is displayed on the monitor as shown in FIG. Diffraction wave 101 Displayed earlier. When such a waveform is measured, which part of the waveforms 100 and 101 is the echo wave 100 and which part is Diffraction wave 101 It is unclear whether this is true, and accurate analysis cannot be performed.
[0042]
For this reason, flaw detection from the lower side of the horizontal plate 91 is also required. That is, the incident probe 92 is brought into contact with the lower surface of the horizontal plate 91, and the receiving probe 93 is brought into contact with one surface of the vertical plate 90 at a position slightly below the horizontal plate 91 to perform flaw detection again. . In the flaw detection from the upper side, the third and fourth waveforms appearing on the monitor screen and the second appearing waveform on the monitor screen in the flaw detection from the lower side are comprehensively analyzed. Identify the position and size of the defect.
[0043]
As described above, in the flaw detection method shown in FIG. 7, it takes time and effort to identify the defect. However, the incident probe 72 is brought into contact with the surface of the weld bead 75 as shown in FIG. By performing the flaw detection by making the ultrasonic wave incident from the surface of the surface, the position size of the defect can be accurately grasped only by the flaw detection from one side.
[0044]
In addition, in FIG. 5, although a mode that two members are flaw-detected and the welding part welded by making a right angle is shown, if two members make | form the predetermined angle and cross | intersect, the angle which members make Is not limited to a right angle.
[0045]
【The invention's effect】
As described above, according to the present invention, the direction in which the ultrasonic wave is incident and the transmission angle, and the direction in which the ultrasonic wave is received and the receivable angle are specified within a predetermined range. In addition, the ultrasonic flaw detection can be very easily performed on a structure having a complicated shape. In addition, since the incident probe and the reception probe can be appropriately selected according to the inspection object, ultrasonic flaw detection can be performed on structures having various shapes.
[0046]
In particular, when flaw detection is performed on a welded part between members that intersect at a predetermined angle, if an incident probe is brought into contact with the surface of the weld bead and ultrasonic waves are incident from the surface of the weld bead, a single flaw is detected. Can be accurately grasped.
[Brief description of the drawings]
FIG. 1 is a diagram showing an aspect in which a structure is flawed using an ultrasonic flaw detector according to an embodiment of the present invention.
FIG. 2 is a diagram showing the internal structure of an incident probe and a receiving probe used in the ultrasonic flaw detector shown in FIG.
3 is an explanatory diagram of a waveform appearing on a monitor device of the ultrasonic flaw detector shown in FIG. 1. FIG.
FIG. 4 is a diagram showing an aspect in which ultrasonic flaw detection is performed on a structure different from the structure shown in FIG.
FIG. 5 is a diagram showing an aspect of an ultrasonic flaw detection method according to another embodiment of the present invention.
6 is an explanatory diagram of waveforms appearing on a monitor when flaw detection is performed by the ultrasonic flaw detection method shown in FIG.
FIG. 7 is a diagram showing a mode in which ultrasonic flaw detection is performed in a mode different from the ultrasonic flaw detection shown in FIG. 5;
FIG. 8 is an explanatory diagram of waveforms appearing on a monitor when flaw detection is performed by the ultrasonic flaw detection method shown in FIG.
FIG. 9 is a diagram showing a mode in which ultrasonic flaw detection is performed by a conventional TOFD method.
10 is an explanatory diagram of waveforms appearing on a monitor when ultrasonic flaw detection is performed by the TOFD method shown in FIG. 9. FIG.
[Explanation of symbols]
1,60,72,92 Incident probe
2,11 casing
3,12 Wedge material
4,13 Top surface
6 Transmitting elements
7 Outgoing surface
10, 60, 73, 93 Reception probe
15 Receiving element
16 Reception surface
20 Transmitter
21 Receiver
22 Monitor device
30,65 Welded part (inspection part)
α, α2 transmission angle
β, β2 Receivable angle
θ1, θ2 tilt angle
φ1, φ3 Angle formed by the direction in which ultrasonic waves are incident and the surface of the inspection object
φ2, φ4 Angle between the direction of the received ultrasonic wave and the surface to be inspected

Claims

In the ultrasonic flaw detection apparatus using the joint portion of the members joined so that the surfaces of each other intersect ,
An incident probe that is arranged on the surface of one of the joined members and makes an ultrasonic wave incident toward the inspection site, and an ultrasonic wave that is arranged on the surface of the other member and made incident by the incident probe. A receiving probe for receiving,
Said incident probe is a co-when the surface of the line and one of the members connecting with the test sites are arranged so as to form a predetermined inclination angle, said receiving probe is connecting with the test site The line and the surface of the other member are arranged to form a predetermined inclination angle,
The incident probe is configured such that a transmission surface is directed to the inspection site side, and ultrasonic waves are incident on the inspection site at a transmission angle of a predetermined spread angle from a transmission element that transmits ultrasonic waves,
The receiving probe includes a receiving element for receiving an ultrasonic wave incident from the incident probe and transmitted through the inspection site, with a receiving surface directed toward the inspection site, and has a predetermined spread angle. Only receive ultrasound within the receivable angle,
An inclination angle formed between the receiving surface and the surface of the other member is formed larger than an inclination angle formed between the transmitting surface and the surface of the one member, and the receiving surface is relatively positioned relative to the transmitting surface. It is greatly tilted toward the examination site,
The ultrasonic flaw detector characterized in that the receivable angle is smaller than the transmission angle.

At least one of the inclination angle or the transmission angle is formed to be different from each other,
Provided with a plurality of incident probe surface of one of said members and the other surface of the member is selected in accordance with the angle,
At least one of the tilt angle and the receivable angle is formed so as to be different from each other,
Ultrasonic flaw detector according to claim 1, characterized in that it comprises a plurality of receiving probe and the surface of the surface and the other of said members of one of said members is selected in accordance with the angle.

The joint part of the members joined so that the surfaces of each other intersect is the inspection site,
An incident probe that allows an ultrasonic wave to be incident on the surface to be inspected is disposed on the surface of one of the joined members, and the ultrasonic wave that is incident on the surface of the other member is received by the incident probe. Place the receiving probe,
A predetermined angle is formed with the surface of one of the members from the incident probe, and an ultrasonic wave is incident on the inspection site at a transmission angle of a predetermined spread angle,
The angle between the ultrasonic direction and the other of said members that are transmitted from the previous SL test sites received by the receiving probe is the incident probe there is a surface of the ultrasonic waves and one of said members having entered together so that the angle becomes smaller angle Nasu, receivable angle a divergence angle relative to the said receiving probe is from the test sites within the scope of the outgoing angle from the coverage angle is small divergence angle An ultrasonic flaw detection method characterized by receiving only transmitted ultrasonic waves.

One of the in accordance with the angle between the surface of the surface and the other of said members of the member, from the incident probe by either changing the one angle or the outgoing angle of the surface of at least one of said members with incident ultrasonic waves, in accordance with the angle between the surface of the surface and the other of said members of one of said members, changing either the angle or the receivable angle of the surface of at least the other of said members The ultrasonic flaw detection method according to claim 3, wherein the ultrasonic wave incident from the incident probe and transmitted from the inspection site is received by the reception probe.

The welded part of the members welded so that the surfaces of each other intersect ,
An incident probe that allows ultrasonic waves to be incident on the inspection site is disposed on the surface of a weld bead that welds these members, and the incident probe is disposed on the surface of one of the members. Place a receiving probe to receive the ultrasonic wave that is incident,
A predetermined angle is formed with the surface of the weld bead from the incident probe, and an ultrasonic wave is incident toward the inspection site at a transmission angle of a predetermined spread angle,
The angle between the ultrasound of the the direction members transferred from the previous SL test sites received by the receiving probe is from the angle that the incident probe is an ultrasonic wave incident and the weld bead surface forms while such a small angle, prior Symbol receiving probe receivable angle a spread angle referenced to is transmitted from the test sites within the scope of the outgoing angle smaller spread angle at which the receivable angle An ultrasonic flaw detection method characterized by receiving only ultrasonic waves.