JP7455056B2 - Eddy current flaw detection system and eddy current flaw detection method - Google Patents

Eddy current flaw detection system and eddy current flaw detection method Download PDF

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JP7455056B2
JP7455056B2 JP2020211708A JP2020211708A JP7455056B2 JP 7455056 B2 JP7455056 B2 JP 7455056B2 JP 2020211708 A JP2020211708 A JP 2020211708A JP 2020211708 A JP2020211708 A JP 2020211708A JP 7455056 B2 JP7455056 B2 JP 7455056B2
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将史 成重
将裕 三木
潤一郎 長沼
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Hitachi GE Nuclear Energy Ltd
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本発明は、検査対象物の探傷検査を行う渦電流探傷システム及び渦電流探傷方法に関する。 The present invention relates to an eddy current flaw detection system and an eddy current flaw detection method for flaw detection of an object to be inspected.

特許文献１は、検査対象物の探傷検査を行う渦電流検査装置を開示する。この渦電流検査装置は、２列で配列されたコイル群を有する渦電流プローブと、渦電流プローブに接続された検査制御装置とを備える。 Patent Document 1 discloses an eddy current inspection device that performs flaw detection on an object to be inspected. This eddy current inspection device includes an eddy current probe having coil groups arranged in two rows, and an inspection control device connected to the eddy current probe.

検査制御装置は、渦電流プローブのコイル群のうちの励磁コイルと検出コイルの組み合わせを順次切り替える制御を行う。詳細には、１列目のコイルのうちの一のコイルを励磁コイルとして選択し、励磁コイルに励磁信号を印加する。これにより、検査対象物に渦電流を発生させる。また、１列目のコイルのうちの他のコイル（言い換えれば、励磁コイルに対し一方側に配置されたコイル）を第１検出コイルとして選択し、その検出信号（詳細には、検査対象物のきずによって生じる渦電流の乱れに相当する信号）を取得する。また、２列目のコイルのうちの一のコイル（言い換えれば、励磁コイルに対し他方側に配置されたコイル）を第２検出コイルとして選択し、その検出信号を取得する。 The inspection control device performs control to sequentially switch combinations of excitation coils and detection coils in the coil group of the eddy current probe. Specifically, one of the coils in the first row is selected as the excitation coil, and an excitation signal is applied to the excitation coil. This causes eddy currents to be generated in the object to be inspected. In addition, another coil among the coils in the first row (in other words, a coil placed on one side with respect to the excitation coil) is selected as the first detection coil, and its detection signal (in detail, A signal corresponding to the eddy current disturbance caused by the flaw) is acquired. Further, one of the coils in the second row (in other words, the coil arranged on the other side with respect to the excitation coil) is selected as the second detection coil, and its detection signal is acquired.

検査制御装置は、第１検出コイルの検出信号からＸ成分（詳細には、励磁信号の位相と同じ成分）とＹ成分（詳細には、励磁信号の位相と９０度異なる成分）を取得し、それらに基づいて第１検出コイルの検出信号の位相角を演算する。同様に、第２検出コイルの検出信号からＸ成分とＹ成分を取得し、それらに基づいて第２検出コイルの検出信号の位相角を演算する。 The inspection control device obtains an X component (specifically, a component that is the same as the phase of the excitation signal) and a Y component (specifically, a component that is 90 degrees different from the phase of the excitation signal) from the detection signal of the first detection coil, Based on these, the phase angle of the detection signal of the first detection coil is calculated. Similarly, the X component and Y component are obtained from the detection signal of the second detection coil, and the phase angle of the detection signal of the second detection coil is calculated based on them.

検査制御装置は、第１検出コイルの検出信号の位相角及び第２検出コイルの検出信号の位相角を座標とする座標系にて予め設定された基準範囲を記憶する。そして、演算された第１検出コイルの検出信号の位相角及び第２検出コイルの検出信号の位相角が基準範囲内にあるか否かにより、検出信号がきず信号に相当するか否かを判定する。そして、検査対象物の表面上の検出位置を示す座標系にて、きず信号に相当すると判定された検出信号の範囲を示す探傷画像を生成し、探傷画像を表示器に表示させる。 The inspection control device stores a reference range preset in a coordinate system whose coordinates are the phase angle of the detection signal of the first detection coil and the phase angle of the detection signal of the second detection coil. Then, it is determined whether the detection signal corresponds to a flaw signal based on whether the calculated phase angle of the detection signal of the first detection coil and the phase angle of the detection signal of the second detection coil are within the reference range. do. Then, a flaw detection image indicating the range of the detection signal determined to correspond to the flaw signal is generated in the coordinate system indicating the detection position on the surface of the inspection object, and the flaw detection image is displayed on the display.

特許第５１３８７１３号公報Patent No. 5138713

特許文献１では、渦電流プローブを検査対象物の表面側に配置して、検査対象物の表面きず（言い換えれば、検査対象物の表面に開口したきず）を検出する。ここで、渦電流プローブを検査対象物の表面側に配置したまま、検査対象物の表面きずだけでなく、裏面きず（言い換えれば、検査対象物の裏面に開口したきず）も検出すれば、検査時間の短縮を図ることが可能である。しかし、検査対象物の表面きずと裏面きずを識別できなければ、その後の対応を判断することが困難である。 In Patent Document 1, an eddy current probe is placed on the surface side of the object to be inspected to detect surface flaws on the object to be inspected (in other words, flaws opened on the surface of the object to be inspected). Here, if the eddy current probe is placed on the front side of the object to be inspected and detects not only the flaws on the surface of the object to be inspected, but also the flaws on the back side (in other words, the flaws that open on the back side of the object to be inspected), the inspection can be completed. It is possible to reduce the time. However, unless it is possible to distinguish between flaws on the front and back surfaces of the object to be inspected, it is difficult to determine what to do next.

本発明の目的は、検査対象物の表面きずと裏面きずを識別して検出することができる渦電流探傷システム及び渦電流探傷方法を提供することにある。 An object of the present invention is to provide an eddy current flaw detection system and an eddy current flaw detection method that can distinguish and detect front and back flaws of an object to be inspected.

上記目的を達成するために、本発明は、少なくとも１つの励磁コイル、前記励磁コイルに対し一方側に配置された第１検出コイル、及び前記励磁コイルに対し他方側に配置された第２検出コイルを有する渦電流プローブと、前記励磁コイルに励磁信号を印加すると共に、前記第１検出コイルの検出信号及び前記第２コイルの検出信号を取得する探傷装置と、コンピュータとを備え、検査対象物の表面きず及び裏面きずを検出する渦電流探傷システムであって、前記コンピュータは、前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角を座標とする座標系にて予め設定された第１基準範囲及び第２基準範囲を記憶し、前記探傷装置で取得された前記第１検出コイルの検出信号に対して位相角を演算すると共に、前記探傷装置で取得された前記第２検出コイルの検出信号に対して位相角を演算し、演算された前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角が前記第１基準範囲内にあるか否かにより、前記検出信号が表面きず信号に相当するか否かを判定すると共に、演算された前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角が前記第２基準範囲内にあるか否かにより、前記検出信号が裏面きず信号に相当するか否かを判定し、その判定結果を出力する。 In order to achieve the above object, the present invention provides at least one excitation coil, a first detection coil disposed on one side with respect to the excitation coil, and a second detection coil disposed on the other side with respect to the excitation coil. an eddy current probe having an eddy current probe; a flaw detection device that applies an excitation signal to the excitation coil and acquires a detection signal of the first detection coil and a detection signal of the second coil; and a computer; An eddy current flaw detection system for detecting surface flaws and back surface flaws, wherein the computer creates a coordinate system in which the phase angle of the detection signal of the first detection coil and the phase angle of the detection signal of the second detection coil are used as coordinates. A first reference range and a second reference range set in advance are stored, and a phase angle is calculated for the detection signal of the first detection coil acquired by the flaw detection device, and a phase angle is calculated for the detection signal of the first detection coil acquired by the flaw detection device. A phase angle is calculated for the detection signal of the second detection coil, and the calculated phase angle of the detection signal of the first detection coil and the phase angle of the detection signal of the second detection coil are within the first reference range. It is determined whether the detection signal corresponds to a surface flaw signal based on whether or not the detection signal corresponds to a surface flaw signal, and the calculated phase angle of the detection signal of the first detection coil and the phase of the detection signal of the second detection coil are determined. Depending on whether the corner is within the second reference range, it is determined whether the detection signal corresponds to a back surface flaw signal, and the determination result is output.

本発明によれば、検査対象物の表面きずと裏面きずを識別して検出することができる。 According to the present invention, it is possible to distinguish and detect flaws on the front surface and flaws on the back surface of an object to be inspected.

本発明の第１の実施形態における渦電流探傷システムの構成を検査対象物と共に表す概略図である。1 is a schematic diagram showing the configuration of an eddy current flaw detection system in a first embodiment of the present invention together with an object to be inspected. 本発明の第１の実施形態における渦電流プローブの構造を表す側面図及び断面図である。1 is a side view and a sectional view showing the structure of an eddy current probe according to a first embodiment of the present invention. FIG. 本発明の第１の実施形態における識別マップを表す図である。It is a figure showing the identification map in the 1st embodiment of the present invention. 本発明の第１の実施形態における表面きず信号が検出された場合の位相角の具体例を説明するための図である。FIG. 6 is a diagram for explaining a specific example of a phase angle when a surface flaw signal is detected in the first embodiment of the present invention. 本発明の第１の実施形態における裏面きず信号が検出された場合の位相角の具体例を説明するための図である。FIG. 7 is a diagram for explaining a specific example of a phase angle when a back surface flaw signal is detected in the first embodiment of the present invention. 本発明の第２の実施形態における位相角マップを表す図である。It is a figure showing the phase angle map in the 2nd embodiment of the present invention.

本発明の第１の実施形態を、図面を参照しつつ説明する。 A first embodiment of the present invention will be described with reference to the drawings.

図１は、本実施形態における渦電流探傷システムの構成を検査対象物と共に表す概略図である。図２（ａ）は、本実施形態における渦電流プローブの構造を表す側面図であり、図２（ｂ）は、図２（ａ）の断面Ｂ－Ｂによる断面図である。 FIG. 1 is a schematic diagram showing the configuration of an eddy current flaw detection system in this embodiment together with an object to be inspected. FIG. 2(a) is a side view showing the structure of the eddy current probe in this embodiment, and FIG. 2(b) is a sectional view taken along section BB in FIG. 2(a).

本実施形態の検査対象物は、圧力容器１の貫通穴に挿入されて溶接された円管２であり、検査部位は、円管２において溶接部３と隣接する部分である。なお、円管２の材質は、ステンレス鋼（非磁性材）であり、圧力容器１の材質は、低合金鋼（磁性材）である。 The object to be inspected in this embodiment is a circular tube 2 inserted into a through hole of a pressure vessel 1 and welded, and the inspection site is a portion of the circular tube 2 adjacent to a welded portion 3. The material of the circular tube 2 is stainless steel (non-magnetic material), and the material of the pressure vessel 1 is low-alloy steel (magnetic material).

本実施形態の渦電流探傷システムは、円管２の表面きず４（言い換えれば、円管２の内面に開口したきず）及び裏面きず５（言い換えれば、円管２の外面に開口したきず）を検出するためのものである。この渦電流探傷システムは、円管２内に配置されてコイル群を有する渦電流プローブ１１と、円管２の軸方向（図１の上下方向）における渦電流プローブ１１の位置を調整するプローブ位置調整装置１２と、渦電流プローブ１１のコイル群を制御する探傷装置１３と、プローブ位置調整装置１２及び探傷装置１３に接続されたコンピュータ１４と、コンピュータ１４に接続された表示器（モニタ）１５とを備える。 The eddy current flaw detection system of this embodiment detects surface flaws 4 of the circular tube 2 (in other words, flaws opening on the inner surface of the circular tube 2) and back surface flaws 5 (in other words, flaws opening on the outer surface of the circular tube 2). It is for detection. This eddy current flaw detection system includes an eddy current probe 11 that is placed inside a circular tube 2 and has a group of coils, and a probe position that adjusts the position of the eddy current probe 11 in the axial direction of the circular tube 2 (vertical direction in FIG. 1). An adjustment device 12, a flaw detection device 13 that controls the coil group of the eddy current probe 11, a computer 14 connected to the probe position adjustment device 12 and the flaw detection device 13, and a display (monitor) 15 connected to the computer 14. Equipped with

渦電流プローブ１１は、円柱形の筐体２１と、筐体２１の外周側に２列で千鳥配列されたコイル群とを有する。軸方向一方側（図１及び図２の上側）に配置された１列目のコイルは、互いに間隔ｄで離間され、軸方向他方側（図１及び図２の下側）に配置された２列目のコイルは、互いに間隔ｄで離間されている。１列目のコイルのうちの一のコイルとこれに隣り合う２列目のコイルのうちの一のコイルは、互いに間隔（ｄ×２）で離間されている。各コイルは、その中心に磁性コアが挿入されており、その中心軸が筐体２１の断面中心に向けられている（図２（ｂ）参照）。なお、筐体２１の材質は、例えば非導電性の樹脂材である。 The eddy current probe 11 has a cylindrical housing 21 and a group of coils arranged in two rows in a staggered manner on the outer circumferential side of the housing 21. The first row of coils arranged on one side in the axial direction (upper side in FIGS. 1 and 2) are spaced apart from each other by a distance d, and the two coils arranged on the other side in the axial direction (lower side in FIGS. 1 and 2) The coils in the row are spaced apart from each other by a distance d. One of the coils in the first row and one of the coils in the second row adjacent thereto are spaced apart from each other by an interval (d×2). A magnetic core is inserted into the center of each coil, and its central axis is directed toward the center of the cross section of the housing 21 (see FIG. 2(b)). Note that the material of the housing 21 is, for example, a non-conductive resin material.

探傷装置１３は、図示しないものの、渦電流プローブ１１のコイル群のうちの励磁コイルと検出コイルの組み合わせを選択するマルチプレクサ回路と、マルチプレクサ回路を介し励磁コイルに励磁信号を印加する発信器と、円管２にきずが無い場合の検出コイルの検出信号がゼロとなるように設定され、マルチプレクサ回路を介し検出コイルの検出信号を取得するブリッジ回路と、検出コイルの検出信号からＸ成分（詳細には、励磁信号の位相と同じ成分）を取得する同期検波回路と、検出コイルの検出信号からＹ成分（詳細には、励磁信号の位相と９０度異なる成分）を取得する同期検波回路とを有する。 Although not shown, the flaw detection device 13 includes a multiplexer circuit that selects a combination of an excitation coil and a detection coil from among the coil groups of the eddy current probe 11, a transmitter that applies an excitation signal to the excitation coil via the multiplexer circuit, and a circuit. The detection signal of the detection coil is set to zero when there is no flaw in the tube 2, and the bridge circuit acquires the detection signal of the detection coil via the multiplexer circuit, and the X component (in detail , the same component as the phase of the excitation signal), and a synchronous detection circuit that acquires the Y component (specifically, a component that differs by 90 degrees from the phase of the excitation signal) from the detection signal of the detection coil.

探傷装置１３は、コンピュータ１４からの指令に応じて、渦電流プローブ１１のコイル群のうちの励磁コイルと検出コイル（詳細には、後述する第１検出コイル又は／及び第２検出コイル）の組み合わせを順次切り替える制御を行う。 The flaw detection device 13 detects a combination of an excitation coil and a detection coil (specifically, a first detection coil and/or a second detection coil, which will be described later) in the coil group of the eddy current probe 11 in accordance with a command from the computer 14. Performs control to switch sequentially.

詳しく説明すると、探傷装置１３は、１列目のコイルのうちの一のコイルを励磁コイル２２として選択し、励磁コイル２２に励磁信号を印加する。これにより、円管２に渦電流を発生させる。なお、本実施形態では、１００ｋHz以上の高周波数（例えば１００kHz）の励磁信号を励磁コイル２２に印加するように設定されている。これにより、１００ｋHz未満の低周波数の励磁信号を励磁コイル２２に印加する場合と比べ、円管２の内面側における渦電流を大きくする。 To explain in detail, the flaw detection device 13 selects one of the coils in the first row as the excitation coil 22 and applies an excitation signal to the excitation coil 22 . This causes an eddy current to be generated in the circular tube 2. Note that in this embodiment, an excitation signal of a high frequency of 100 kHz or higher (for example, 100 kHz) is applied to the excitation coil 22. This increases the eddy current on the inner surface of the circular tube 2 compared to the case where a low frequency excitation signal of less than 100 kHz is applied to the excitation coil 22.

また、探傷装置１３は、１列目のコイルのうちの他のコイル（言い換えれば、励磁コイル２２に対し一方側に配置され、間隔（ｄ×２）だけ離れたコイル）を第１検出コイル２３Ａとして選択し、その検出信号を取得する。そして、第１検出コイル２３Ａの検出信号からＸ成分とＹ成分を取得し、コンピュータ１４に出力する。 In addition, the flaw detection device 13 detects the other coils among the coils in the first row (in other words, the coils arranged on one side with respect to the excitation coil 22 and separated by the interval (d×2)) from the first detection coil 23A. and obtain its detection signal. Then, the X component and Y component are acquired from the detection signal of the first detection coil 23A and output to the computer 14.

また、探傷装置１３は、２列目のコイルのうちの一のコイル（言い換えれば、励磁コイル２２に対し他方側に配置され、間隔（ｄ×２）だけ離れたコイル）を第２検出コイル２３Ｂとして選択し、その検出信号を取得する。そして、第２検出コイル２３Ｂの検出信号からＸ成分とＹ成分を取得し、コンピュータ１４に出力する。 The flaw detector 13 also selects one of the coils in the second row (in other words, the coil that is arranged on the other side of the excitation coil 22 and is spaced apart by a distance (d x 2)) as the second detection coil 23B and acquires its detection signal. Then, it acquires the X component and the Y component from the detection signal of the second detection coil 23B and outputs them to the computer 14.

コンピュータ１４は、プローブ位置調整装置１２を制御して、円管２の軸方向における渦電流プローブ１１の位置を調整する。そして、渦電流プローブ１１の位置と励磁コイル２２の選択位置に基づいて、円管２の内面上の検出位置を演算する。 The computer 14 controls the probe position adjustment device 12 to adjust the position of the eddy current probe 11 in the axial direction of the circular tube 2. Then, a detection position on the inner surface of the circular tube 2 is calculated based on the position of the eddy current probe 11 and the selected position of the excitation coil 22.

コンピュータ１４は、第１検出コイル２３Ａの検出信号におけるＸ成分とＹ成分に基づいて、第１検出コイル２３Ａの検出信号の位相角θ１を演算する。また、第２検出コイル２３Ｂの検出信号におけるＸ成分とＹ成分に基づいて、第２検出コイル２３Ｂの検出信号の位相角θ２を演算する。 The computer 14 calculates the phase angle θ1 of the detection signal of the first detection coil 23A based on the X component and Y component of the detection signal of the first detection coil 23A. Furthermore, the phase angle θ2 of the detection signal of the second detection coil 23B is calculated based on the X component and Y component of the detection signal of the second detection coil 23B.

コンピュータ１４は、第１検出コイル２３Ａの検出信号の位相角を横軸、第２検出コイル２３Ｂの検出信号の位相角を縦軸とする座標系にて、予め設定された基準範囲ＡＢＣＤ、基準範囲ＧＨＩＪ、基準範囲ＡＢＣＥＦ、及び基準範囲ＧＨＩＫＬを示す、識別マップ（図３参照）を記憶している。そして、演算された第１検出コイル２３Ａの検出信号の位相角θ１及び第２検出コイル２３Ｂの検出信号の位相角が基準範囲ＡＢＣＤ又は基準範囲ＧＨＩＪに含まれるか否かにより、検出信号が表面きず信号に相当するか否かを判定する。また、演算された第１検出コイル２３Ａの検出信号の位相角θ１及び第２検出コイル２３Ｂの検出信号の位相角θ２が基準範囲ＡＢＣＥＦ又は基準範囲ＧＨＩＫＬに含まれるか否かにより、検出信号が裏面きず信号に相当するか否かを判定する。以下、その詳細を説明する。 The computer 14 uses a coordinate system in which the horizontal axis is the phase angle of the detection signal of the first detection coil 23A and the vertical axis is the phase angle of the detection signal of the second detection coil 23B. It stores an identification map (see FIG. 3) showing GHIJ, reference range ABCEF, and reference range GHIKL. Then, depending on whether the calculated phase angle θ1 of the detection signal of the first detection coil 23A and the phase angle of the detection signal of the second detection coil 23B are included in the reference range ABCD or the reference range GHIJ, the detection signal is detected as a surface flaw. Determine whether it corresponds to a signal. Also, depending on whether the calculated phase angle θ1 of the detection signal of the first detection coil 23A and phase angle θ2 of the detection signal of the second detection coil 23B are included in the reference range ABCEF or the reference range GHIKL, the detection signal is It is determined whether the signal corresponds to a flaw signal. The details will be explained below.

図４（ａ）で示すように、円管２の表面きず４が円管２の周方向に延在する場合、渦電流プローブ１１の励磁コイル２２と第１検出コイル２３Ａの配置方向は、表面きず４の長さ方向に対しほぼ平行となる。そのため、図４（ｂ）で示すように、第１検出コイル２３Ａの検出信号をリサージュ図にプロットすると、リサージュ波形３１が現れ、例えば位相角θ１＝９０°が得られる。渦電流プローブ１１の励磁コイル２２と第２検出コイル２３Ｂの配置方向は、表面きず４の長さ方向に対しほぼ垂直となる。そのため、第２検出コイル２３Ｂの検出信号をリサージュ図にプロットすると、リサージュ波形３２が現れ、例えば位相角θ２＝２５０°が得られる。したがって、表面きず信号は、識別マップの基準範囲ＡＢＣＤ、詳細には、点Ａ（座標（（θ１ａ－Δθ），（θ２ａ＋Δθ）））、点Ｂ（座標（（θ１ａ－Δθ），（θ２ａ－θ）））、点Ｃ（座標（（θ１ａ＋Δθ），（θ２ａ－Δθ）））、及び点Ｄ（座標（（θ１ａ＋Δθ），（θ２ａ＋Δθ）））で囲まれる領域に含まれる（但し、例えばθ１ａ＝９０°、θ２ａ＝２５０°、Δθ＝２０°）。 As shown in FIG. 4(a), when the surface flaw 4 of the circular tube 2 extends in the circumferential direction of the circular tube 2, the arrangement direction of the excitation coil 22 and the first detection coil 23A of the eddy current probe 11 is It is almost parallel to the length direction of the flaw 4. Therefore, as shown in FIG. 4(b), when the detection signal of the first detection coil 23A is plotted on a Lissajous diagram, a Lissajous waveform 31 appears and, for example, a phase angle θ1=90° is obtained. The arrangement direction of the excitation coil 22 and the second detection coil 23B of the eddy current probe 11 is substantially perpendicular to the length direction of the surface flaw 4. Therefore, when the detection signal of the second detection coil 23B is plotted on a Lissajous diagram, a Lissajous waveform 32 appears, and, for example, a phase angle θ2=250° is obtained. Therefore, the surface flaw signal corresponds to the reference range ABCD of the identification map, specifically, point A (coordinates ((θ1a - Δθ), (θ2a + Δθ))), point B (coordinates ((θ1a - Δθ), (θ2a - θ ))), point C (coordinates ((θ1a+Δθ), (θ2a−Δθ)))), and point D (coordinates ((θ1a+Δθ), (θ2a+Δθ)))) (However, for example, θ1a=90 °, θ2a=250°, Δθ=20°).

図示しないが、円管２の表面きず４が円管２の軸方向に延在する場合は、反対に、励磁コイル２２と第１検出コイル２３Ａの配置方向が表面きず４の長さ方向に対しほぼ垂直となり、励磁コイル２２と第２検出コイル２３Ｂの配置方向が表面きず４の長さ方向に対しほぼ平行となる。そのため、第１検出コイル２３Ａの検出信号の位相角θ１＝２５０°、第２検出コイル２３Ｂの検出信号の位相角θ２＝９０°が得られる。したがって、表面きず信号は、識別マップの基準範囲ＧＨＩＪ、詳細には、点Ｇ（座標（（θ１ｂ－Δθ），（θ２ｂ＋Δθ）））、点Ｈ（座標（（θ１ｂ－Δθ），（θ２ｂ－Δθ）））、点Ｉ（座標（（θ１ｂ＋Δθ），（θ２ｂ－Δθ）））、及び点Ｊ（座標（（θ１ｂ＋Δθ），（θ２ｂ＋Δθ）））で囲まれる領域に含まれる（但し、例えばθ１ｂ＝２５０°、θ２ｂ＝９０°、Δθ＝２０°）。 Although not shown, when the surface flaw 4 of the circular tube 2 extends in the axial direction of the circular tube 2, on the contrary, the arrangement direction of the excitation coil 22 and the first detection coil 23A is relative to the length direction of the surface flaw 4. The arrangement direction of the excitation coil 22 and the second detection coil 23B is substantially parallel to the length direction of the surface flaw 4. Therefore, the phase angle θ1 of the detection signal of the first detection coil 23A is 250°, and the phase angle θ2 of the detection signal of the second detection coil 23B is 90°. Therefore, the surface flaw signal corresponds to the reference range GHIJ of the identification map, specifically, point G (coordinates ((θ1b - Δθ), (θ2b + Δθ))), point H (coordinates ((θ1b - Δθ), (θ2b - Δθ) )))), point I (coordinates ((θ1b + Δθ), (θ2b - Δθ)))), and point J (coordinates ((θ1b + Δθ), (θ2b + Δθ)))) (However, for example, θ1b = 250 °, θ2b=90°, Δθ=20°).

図５（ａ）で示すように、円管２の裏面きず５が円管２の周方向に延在する場合、渦電流プローブ１１の励磁コイル２２と第１検出コイル２３Ａの配置方向は、裏面きず５の長さ方向に対しほぼ平行となる。そのため、円管２の内面と裏面きず５の間における残肉の厚さが０．３ｍｍである場合は、図５（ｂ）で示すように、第１検出コイル２３Ａの検出信号をリサージュ図にプロットすると、リサージュ波形３３が現れ、例えば位相角θ１＝１５°が得られる。渦電流プローブ１１の励磁コイル２２と第２検出コイル２３Ｂの配置方向は、裏面きず５の長さ方向に対しほぼ垂直となる。そのため、図５（ｃ）で示すように、第２検出コイル２３Ｂの検出信号をリサージュ図にプロットすると、リサージュ波形３４が現れ、例えば位相角θ２＝１７５°が得られる。なお、残肉の厚さが０．６ｍｍである場合は、例えば第１検出コイル２３Ａの検出信号の位相角θ１＝０°、第２検出コイル２３Ｂの検出信号の位相角θ２＝１６０°が得られる。すなわち、座標は、残肉の厚さに応じて、図中の一点鎖線に沿って変化する。したがって、裏面きず信号は、識別マップの基準範囲ＡＢＣＥＦ、詳細には、点Ａ、点Ｂ、点Ｃ、点Ｅ（座標（０，（θ２ａ－θ）－（θ１ａ＋Δθ）））、及び点Ｆ（座標（０，（θ２ａ＋Δθ）－（θ１ａ－Δθ）））で囲まれる領域に含まれる。 As shown in FIG. 5(a), when the back surface flaw 5 of the circular tube 2 extends in the circumferential direction of the circular tube 2, the arrangement direction of the excitation coil 22 and the first detection coil 23A of the eddy current probe 11 is It is almost parallel to the length direction of the flaw 5. Therefore, when the thickness of the remaining wall between the inner surface of the circular tube 2 and the back surface flaw 5 is 0.3 mm, the detection signal of the first detection coil 23A is expressed in the Lissajous diagram as shown in FIG. 5(b). When plotted, a Lissajous waveform 33 appears and, for example, a phase angle θ1=15° is obtained. The arrangement direction of the excitation coil 22 and the second detection coil 23B of the eddy current probe 11 is substantially perpendicular to the length direction of the back surface flaw 5. Therefore, as shown in FIG. 5C, when the detection signal of the second detection coil 23B is plotted on a Lissajous diagram, a Lissajous waveform 34 appears, and, for example, a phase angle θ2=175° is obtained. Note that when the thickness of the remaining thickness is 0.6 mm, for example, the phase angle θ1 of the detection signal of the first detection coil 23A is 0°, and the phase angle θ2 of the detection signal of the second detection coil 23B is 160°. It will be done. That is, the coordinates change along the dashed line in the figure depending on the thickness of the remaining thickness. Therefore, the back side flaw signal corresponds to the reference range ABCEF of the identification map, specifically, point A, point B, point C, point E (coordinates (0, (θ2a-θ)-(θ1a+Δθ))), and point F ( It is included in the area surrounded by the coordinates (0, (θ2a+Δθ)−(θ1a−Δθ))).

図示しないが、円管２の裏面きず５が円管２の軸方向に延在する場合は、反対に、励磁コイル２２と第１検出コイル２３Ａの配置方向が裏面きず５の長さ方向に対しほぼ垂直となり、励磁コイル２２と第２検出コイル２３Ｂの配置方向が裏面きず５の長さ方向に対しほぼ平行となる。そのため、残肉の厚さが０．３ｍｍである場合は、例えば第１検出コイル２３Ａの検出信号の位相角θ１＝１７５°、第２検出コイル２３Ｂの検出信号の位相角θ２＝１５°が得られる。また、残肉の厚さが０．６ｍｍである場合は、例えば第１検出コイル２３Ａの検出信号の位相角θ１＝１６０°、第２検出コイル２３Ｂの検出信号の位相角θ２＝０°が得られる。したがって、裏面きず信号は、識別マップの基準範囲ＧＨＩＫＬ、詳細には、点Ｇ、点Ｈ、点Ｉ、点Ｋ（座標（（θ１ｂ＋Δθ）－（θ２ｂ－Δθ），０）））、及び点Ｌ（座標（（θ１ｂ－Δθ）－（θ２ｂ＋Δθ），０）））で囲まれる領域に含まれる。 Although not shown, when the back surface flaw 5 of the circular tube 2 extends in the axial direction of the circular tube 2, on the contrary, the arrangement direction of the excitation coil 22 and the first detection coil 23A is relative to the length direction of the back surface flaw 5. The arrangement direction of the excitation coil 22 and the second detection coil 23B is substantially parallel to the length direction of the back surface flaw 5. Therefore, if the remaining thickness is 0.3 mm, for example, the phase angle θ1 of the detection signal of the first detection coil 23A is 175°, and the phase angle θ2 of the detection signal of the second detection coil 23B is 15°. It will be done. Further, when the thickness of the remaining thickness is 0.6 mm, for example, the phase angle θ1 of the detection signal of the first detection coil 23A is 160°, and the phase angle θ2 of the detection signal of the second detection coil 23B is 0°. It will be done. Therefore, the back side flaw signal is based on the reference range GHIKL of the identification map, specifically, point G, point H, point I, point K (coordinates ((θ1b + Δθ) - (θ2b - Δθ), 0))), and point L It is included in the area surrounded by (coordinates ((θ1b−Δθ)−(θ2b+Δθ), 0))).

なお、渦電流プローブ１１が円管２の内面から浮いた場合に、リフトオフ信号が検出される。リフトオフ信号は、｜θ２－θ１｜≦Δθの範囲に含まれ、上述した基準範囲ＡＢＣＤ、基準範囲ＧＨＩＪ、基準範囲ＡＢＣＥＦ、及び基準範囲ＧＨＩＫＬに含まれない。 Note that when the eddy current probe 11 floats from the inner surface of the circular tube 2, a lift-off signal is detected. The lift-off signal is included in the range of |θ2−θ1|≦Δθ, and is not included in the above-mentioned reference range ABCD, reference range GHIJ, reference range ABCEF, and reference range GHIKL.

上述した観点により、コンピュータ１４は、第１検出コイル２３Ａの検出信号の位相角θ１及び第２検出コイル２３Ｂの検出信号の位相角θ２が基準範囲ＡＢＣＤ又は基準範囲ＧＨＩＪに含まれるか否かにより、検出信号が表面きず信号に相当するか否かを判定することが可能である。また、第１検出コイル２３Ａの検出信号の位相角θ１及び第２検出コイル２３Ｂの検出信号の位相角θ２が基準範囲ＡＢＣＥＦ又は基準範囲ＧＨＩＫＬに含まれるか否かにより、検出信号が裏面きず信号に相当するか否かを判定することが可能である。 From the above-mentioned viewpoint, the computer 14 determines whether the phase angle θ1 of the detection signal of the first detection coil 23A and the phase angle θ2 of the detection signal of the second detection coil 23B are included in the reference range ABCD or the reference range GHIJ. It is possible to determine whether the detection signal corresponds to a surface flaw signal. Also, depending on whether the phase angle θ1 of the detection signal of the first detection coil 23A and the phase angle θ2 of the detection signal of the second detection coil 23B are included in the reference range ABCEF or the reference range GHIKL, the detection signal becomes the back side flaw signal. It is possible to determine whether they correspond.

コンピュータ１４は、円管２の周方向及び軸方向における検出位置を示す座標系にて、表面きず信号に相当すると判定された検出信号の範囲を示す第１の探傷画像を生成し、第１の探傷画像を表示器１５に出力して表示させる。これにより、作業者は、円管２の表面きず４を確認することができ、その後の対応として、例えば表面きず４のサイジングを実施する。 The computer 14 generates a first flaw detection image indicating the range of the detection signal determined to correspond to the surface flaw signal in a coordinate system indicating the detection position in the circumferential direction and the axial direction of the circular tube 2, and The flaw detection image is output to the display 15 and displayed. Thereby, the operator can confirm the surface flaw 4 of the circular pipe 2, and as a subsequent countermeasure, for example, performs sizing of the surface flaw 4.

また、コンピュータ１４は、円管２の周方向及び軸方向における検出位置を示す座標系にて、裏面きず信号に相当すると判定された検出信号の範囲を示す第２の探傷画像を生成し、第２の探傷画像を表示器１５に出力して表示させる。これにより、作業者は、円管２の裏面きず５を確認することができ、その後の対応として、例えば超音波探傷又は目視検査を実施する。 Further, the computer 14 generates a second flaw detection image indicating the range of the detection signal determined to correspond to the backside flaw signal in the coordinate system indicating the detection position in the circumferential direction and the axial direction of the circular tube 2, and The flaw detection image No. 2 is output to the display 15 and displayed. This allows the operator to check the flaws 5 on the back surface of the circular tube 2, and then performs, for example, ultrasonic flaw detection or visual inspection.

以上のように本実施形態においては、円管２内に配置された渦電流プローブ１１を用いて、円管２の表面きず４だけでなく、円管２の裏面きず５を検出することができる。そのため、検査時間の短縮を図ることができる。また、円管２の表面きず４と裏面きず５を識別することができる。そのため、その後の対応を容易に判断することができる。 As described above, in this embodiment, not only the surface flaw 4 of the circular tube 2 but also the back surface flaw 5 of the circular tube 2 can be detected using the eddy current probe 11 placed inside the circular tube 2. . Therefore, the inspection time can be shortened. Moreover, the surface flaw 4 and the back surface flaw 5 of the circular tube 2 can be distinguished. Therefore, subsequent actions can be easily determined.

また、本実施形態においては、渦電流プローブ１１の励磁コイル２２に印加する励磁信号の周波数を高くすることにより、円管２の内面側における渦電流を大きくして、表面きずの検出精度を高めることができる。 In addition, in this embodiment, by increasing the frequency of the excitation signal applied to the excitation coil 22 of the eddy current probe 11, the eddy current on the inner surface side of the circular tube 2 is increased, thereby increasing the detection accuracy of surface flaws. be able to.

本実施形態の第２の実施形態を説明する。なお、本実施形態において、第１の実施形態と同等の部分は同一の符号を付し、適宜、説明を省略する。 A second embodiment of this embodiment will be described. In addition, in this embodiment, parts equivalent to those in the first embodiment are given the same reference numerals, and description thereof will be omitted as appropriate.

本実施形態では、１００ｋHz未満の低周波数（例えば２５kHz）の励磁信号を励磁コイルに印加するように設定されている。これにより、１００ｋHz以上の高周波数の励磁信号を励磁コイル２２に印加する場合と比べ、円管２における渦電流の浸透深さを深くする。 In this embodiment, an excitation signal with a low frequency of less than 100 kHz (for example, 25 kHz) is applied to the excitation coil. Thereby, the penetration depth of the eddy current in the circular tube 2 is increased compared to the case where a high frequency excitation signal of 100 kHz or more is applied to the excitation coil 22.

コンピュータ１４は、第１検出コイル２３Ａの検出信号の位相角を横軸、第２検出コイル２３Ｂの検出信号の位相角を縦軸とする座標系にて、予め設定された基準範囲ＡＢＣＤ、基準範囲ＧＨＩＪ、基準範囲ＡＢＣＥ’Ｆ’、及び基準範囲ＧＨＩＫ’Ｌ’を示す、識別マップ（図６参照）を記憶している。そして、演算された第１検出コイル２３Ａの検出信号の位相角θ１及び第２検出コイル２３Ｂの検出信号の位相角θ２が基準範囲ＡＢＣＤ又は基準範囲ＧＨＩＪに含まれるか否かにより、検出信号が表面きず信号に相当するか否かを判定する。また、演算された第１検出コイル２３Ａの検出信号の位相角θ１及び第２検出コイル２３Ｂの検出信号の位相角θ２が基準範囲ＡＢＣＥ’Ｆ’又は基準範囲ＧＨＩＫ’Ｌ’に含まれるか否かにより、検出信号が裏面きず信号に相当するか否かを判定する。 The computer 14 stores an identification map (see FIG. 6) showing preset reference ranges ABCD, GHIJ, ABCE'F', and GHIK'L' in a coordinate system with the phase angle of the detection signal of the first detection coil 23A as the horizontal axis and the phase angle of the detection signal of the second detection coil 23B as the vertical axis. Then, depending on whether the calculated phase angle θ1 of the detection signal of the first detection coil 23A and the phase angle θ2 of the detection signal of the second detection coil 23B are included in the reference range ABCD or the reference range GHIJ, it is determined whether the detection signal corresponds to a surface flaw signal. Also, depending on whether the calculated phase angle θ1 of the detection signal of the first detection coil 23A and the phase angle θ2 of the detection signal of the second detection coil 23B are included in the reference range ABCD or the reference range GHIK'L, it is determined whether the detection signal corresponds to a back flaw signal.

ここで、表面きず信号の判定に用いる基準範囲ＡＢＣＤ及び基準範囲ＧＨＩＪは、第１の実施形態と同じであるものの、裏面きず信号の判定に用いる基準範囲ＡＢＣＥ’Ｆ’及び基準範囲ＧＨＩＫ’Ｌ’は、第１の実施形態と異なる理由について説明する。一般的に、円管２の表面側の渦電流が裏面側の渦電流より大きいことから、探傷装置１３は、円管２の表面側の渦電流を基準として校正されている。そのため、表面きず信号に相当する第１検出コイル２３Ａの検出信号及び第２検出コイル２３Ｂの検出信号に関し、それらの位相角は、励磁コイル２２に印加する励磁信号の周波数が変化しても、ほとんど変化しない。 Here, the reference range ABCD and the reference range GHIJ used for determining the front surface flaw signal are the same as in the first embodiment, but the reference range ABCE'F' and the reference range GHIK'L' used for determining the back surface flaw signal are the same as in the first embodiment. will explain the reason why this embodiment differs from the first embodiment. Generally, the eddy current on the front side of the circular tube 2 is larger than the eddy current on the back side, so the flaw detection device 13 is calibrated using the eddy current on the front side of the circular tube 2 as a reference. Therefore, regarding the detection signal of the first detection coil 23A and the detection signal of the second detection coil 23B, which correspond to the surface flaw signal, their phase angles are almost constant even if the frequency of the excitation signal applied to the excitation coil 22 changes. It does not change.

一方、裏面きず信号に相当する第１検出コイル２３Ａの検出信号及び第２検出コイル２３Ｂの検出信号に関し、それらの位相角は、表面きず信号に相当する第１検出コイル２３Ａの検出信号及び第２検出コイル２３Ｂの検出信号のものより変化しており、それらの変化量は、励磁コイル２２に印加する励磁信号の周波数が低くなるほど、小さくなる。 On the other hand, regarding the detection signal of the first detection coil 23A and the detection signal of the second detection coil 23B, which correspond to the back surface flaw signal, their phase angles are It changes from that of the detection signal of the detection coil 23B, and the amount of change becomes smaller as the frequency of the excitation signal applied to the excitation coil 22 becomes lower.

具体例として、円管２の裏面きず５が円管２の周方向に延在し、残肉の厚さが０．３ｍｍである場合は、例えば第１検出コイル２３Ａの検出信号の位相角θ１＝４５°、第２検出コイル２３Ｂの検出信号の位相角θ２＝２０５°が得られる。円管２の裏面きず５が円管２の周方向に延在し、残肉の厚さが０．６ｍｍである場合は、例えば第１検出コイル２３Ａの検出信号の位相角θ１＝３０°、第２検出コイルの検出信号の位相角θ２＝１９０°が得られる。円管２の裏面きず５が円管２の軸方向に延在し、残肉の厚さが０．３ｍｍである場合は、例えば第１検出コイル２３Ａの検出信号の位相角θ１＝２０５°、第２検出コイル２３Ｂの検出信号の位相角θ２＝４５°が得られる。円管２の裏面きず５が円管２の軸方向に延在し、残肉の厚さが０．６ｍｍである場合は、例えば第１検出コイル２３Ａの検出信号の位相角θ１＝１９０°、第２検出コイル２３Ｂの検出信号の位相角θ２＝３０°が得られる。 As a specific example, if the back surface flaw 5 of the circular tube 2 extends in the circumferential direction of the circular tube 2 and the thickness of the remaining wall is 0.3 mm, for example, the phase angle θ1 of the detection signal of the first detection coil 23A =45°, and the phase angle θ2 of the detection signal of the second detection coil 23B is obtained =205°. When the back surface flaw 5 of the circular tube 2 extends in the circumferential direction of the circular tube 2 and the thickness of the remaining wall is 0.6 mm, for example, the phase angle θ1 of the detection signal of the first detection coil 23A is 30°, A phase angle θ2=190° of the detection signal of the second detection coil is obtained. When the back surface flaw 5 of the circular tube 2 extends in the axial direction of the circular tube 2 and the thickness of the remaining wall is 0.3 mm, for example, the phase angle θ1 of the detection signal of the first detection coil 23A is 205°, A phase angle θ2=45° of the detection signal of the second detection coil 23B is obtained. When the back surface flaw 5 of the circular tube 2 extends in the axial direction of the circular tube 2 and the thickness of the remaining wall is 0.6 mm, for example, the phase angle θ1 of the detection signal of the first detection coil 23A is 190°, A phase angle θ2=30° of the detection signal of the second detection coil 23B is obtained.

上述した本実施形態においても、第１の実施形態と同様、円管２内に配置された渦電流プローブ１１を用いて、円管２の表面きず４だけでなく、円管２の裏面きず５を検出することができる。そのため、検査時間の短縮を図ることができる。また、円管２の表面きず４と裏面きず５を識別することができる。そのため、その後の対応を容易に判断することができる。 In the present embodiment described above, as in the first embodiment, the eddy current probe 11 placed inside the circular tube 2 is used to detect not only the surface flaws 4 of the circular tube 2 but also the back surface flaws 5 of the circular tube 2. can be detected. Therefore, the inspection time can be shortened. Moreover, the surface flaw 4 and the back surface flaw 5 of the circular tube 2 can be distinguished. Therefore, subsequent actions can be easily determined.

また、本実施形態においては、渦電流プローブ１１の励磁コイル２２に印加する励磁信号の周波数を低くすることにより、円管２における渦電流の浸透深さを深くして、裏面きず５の検出精度を高めることができる。 In addition, in this embodiment, by lowering the frequency of the excitation signal applied to the excitation coil 22 of the eddy current probe 11, the penetration depth of the eddy current in the circular tube 2 is increased, and the detection accuracy of the back surface flaw 5 is increased. can be increased.

なお、第１の実施形態においては、高周波数の励磁信号を用いる場合を例にとり、第２の実施形態においては、低周波数の励磁信号を用いる場合を例にとって説明したが、それらを組み合わせてもよい。この変形例について説明する。 Note that in the first embodiment, the case where a high-frequency excitation signal is used is used as an example, and in the second embodiment, the case is explained using a low-frequency excitation signal, but they can also be combined. good. This modification will be explained.

本変形例の探傷装置１３は、高周波数（例えば１００kHz）の励磁信号と低周波数（例えば２５kHz）の励磁信号を励磁コイル２２に選択的に印加する。これにより、高周波数の励磁信号を励磁コイル２２に印加した場合の第１検出コイル２３Ａの検出信号及び第２検出コイル２３Ｂの検出信号と、低周波数の励磁信号を励磁コイル２２に印加した場合の第１検出コイル２３Ａの検出信号及び第２検出コイル２３Ｂの検出信号を取得する。 The flaw detection device 13 of this modification selectively applies a high frequency (for example, 100 kHz) excitation signal and a low frequency (for example, 25 kHz) excitation signal to the excitation coil 22. As a result, the detection signal of the first detection coil 23A and the detection signal of the second detection coil 23B when a high frequency excitation signal is applied to the excitation coil 22, and the detection signal of the second detection coil 23B when a low frequency excitation signal is applied to the excitation coil 22, are determined. A detection signal of the first detection coil 23A and a detection signal of the second detection coil 23B are acquired.

本変形例のコンピュータ１４は、第１の実施形態と同様、高周波数の励磁信号を励磁コイル２２に印加した場合の第１検出コイル２３Ａの検出信号の位相角及び第２検出コイル２３Ｂの検出信号の位相角が基準範囲内にあるか否かにより、検出信号が表面きず信号に相当するか否かを判定する。また、第２の実施形態と同様、低周波数の交流信号を励磁コイル２２に印加した場合の第１検出コイル２３Ａの検出信号の位相角及び第２検出コイル２３Ｂの検出信号の位相角が基準範囲内にあるか否かにより、検出信号が裏面きず信号に相当するか否かを判定する。 Similarly to the first embodiment, the computer 14 of this modification has the phase angle of the detection signal of the first detection coil 23A and the detection signal of the second detection coil 23B when a high frequency excitation signal is applied to the excitation coil 22. It is determined whether the detection signal corresponds to a surface flaw signal based on whether the phase angle of is within the reference range. Further, similarly to the second embodiment, when a low-frequency AC signal is applied to the excitation coil 22, the phase angle of the detection signal of the first detection coil 23A and the phase angle of the detection signal of the second detection coil 23B are within the reference range. It is determined whether the detection signal corresponds to the back surface flaw signal based on whether or not the detection signal is within the range.

上述した本変形例においても、第１及び第２の実施形態と同様の効果を得ることができる。また、本変形例においては、表面きず４の検出精度と裏面きず５の検出精度を両方とも高めることができる。 Also in this modification described above, the same effects as in the first and second embodiments can be obtained. Moreover, in this modification, both the detection accuracy of the front surface flaw 4 and the detection accuracy of the back surface flaw 5 can be improved.

なお、第１及び第２の実施形態並びに変形例において、特に説明しなかったが、コンピュータ１４は、検出信号が裏面きず信号に相当すると判定した場合に、第１検出コイル２３Ａの検出信号の位相角及び第２検出コイル２３Ｂの検出信号の位相角のうちの少なくとも一方に基づき、円管２の内面（検査対象物の表面）と裏面きず５の間の残肉の厚さを推定してもよい。すなわち、コンピュータ１４は、第１検出コイル２３Ａの検出信号の位相角及び第２検出コイル２３Ｂの検出信号の位相角のうちの少なくとも一方と残肉の厚さとの関係を予め記憶しており、これを用いて残肉の厚さを推定してもよい。 Although not particularly described in the first and second embodiments and modifications, when the computer 14 determines that the detection signal corresponds to the back surface flaw signal, the computer 14 adjusts the phase of the detection signal of the first detection coil 23A. The thickness of the remaining wall between the inner surface of the circular tube 2 (the surface of the object to be inspected) and the back surface flaw 5 can be estimated based on at least one of the angle and the phase angle of the detection signal of the second detection coil 23B. good. That is, the computer 14 stores in advance the relationship between the thickness of the remaining thickness and at least one of the phase angle of the detection signal of the first detection coil 23A and the phase angle of the detection signal of the second detection coil 23B. The remaining thickness may be estimated using

また、第１及び第２の実施形態並びに変形例において、検査対象物が円管２であり、渦電流プローブ１１は、円管２に対応するように円柱状に構成された場合を例にとって説明したが、これに限られない。検査対象物が平板であり、渦電流探傷プローブは、平板に対応するように平板状に構成されてもよい。 In addition, in the first and second embodiments and modified examples, the case where the object to be inspected is a circular tube 2 and the eddy current probe 11 is configured in a cylindrical shape to correspond to the circular tube 2 will be explained as an example. However, it is not limited to this. The object to be inspected may be a flat plate, and the eddy current flaw detection probe may be configured to have a flat plate shape so as to correspond to the flat plate.

また、第１及び第２の実施形態並びに変形例において、渦電流プローブ１１は、２列で配列されたコイル群を有する場合を例にとって説明したが、これに限られず、３列以上で配列されたコイル群を有してもよい。 In addition, in the first and second embodiments and modifications, the eddy current probe 11 has been described with reference to the case where the coil group is arranged in two rows, but the eddy current probe 11 is not limited to this, and the eddy current probe 11 has a coil group arranged in three or more rows. It may also have a coil group.

また、第１及び第２の実施形態並びに変形例において、コンピュータ１４は、探傷画像を表示器１５に出力して表示させる場合を例にとって説明したが、これに限られず、例えば、印刷機に出力して印刷させてもよいし、あるいは、記憶媒体に出力して記憶させてもよい。 Furthermore, in the first and second embodiments and modifications, the case where the computer 14 outputs the flaw detection image to the display 15 for display has been explained as an example, but the invention is not limited to this, and for example, the computer 14 outputs the flaw detection image to the printing machine. It may be printed out, or it may be output and stored on a storage medium.

２ 円管
１１ 渦電流プローブ
１３ 探傷装置
１４ コンピュータ
２２ 励磁コイル
２３Ａ 第１検出コイル
２３Ｂ 第２検出コイル 2 Circular tube 11 Eddy current probe 13 Flaw detection device 14 Computer 22 Excitation coil 23A First detection coil 23B Second detection coil

Claims (6)

少なくとも１つの励磁コイル、前記励磁コイルに対し一方側に配置された第１検出コイル、及び前記励磁コイルに対し他方側に配置された第２検出コイルを有する渦電流プローブと、
前記励磁コイルに励磁信号を印加すると共に、前記第１検出コイルの検出信号及び前記第２検出コイルの検出信号を取得する探傷装置と、
コンピュータとを備え、
検査対象物の表面きず及び裏面きずを検出する渦電流探傷システムであって、
前記コンピュータは、
前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角を座標とする座標系にて予め設定された第１基準範囲及び第２基準範囲を記憶し、
前記探傷装置で取得された前記第１検出コイルの検出信号に対して位相角を演算すると共に、前記探傷装置で取得された前記第２検出コイルの検出信号に対して位相角を演算し、
演算された前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角が前記第１基準範囲内にあるか否かにより、前記検出信号が表面きず信号に相当するか否かを判定すると共に、演算された前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角が前記第２基準範囲内にあるか否かにより、前記検出信号が裏面きず信号に相当するか否かを判定し、
その判定結果を出力することを特徴とする渦電流探傷システム。 an eddy current probe having at least one excitation coil, a first detection coil disposed on one side with respect to the excitation coil, and a second detection coil disposed on the other side with respect to the excitation coil;
a flaw detection device that applies an excitation signal to the excitation coil and acquires a detection signal of the first detection coil and a detection signal of the second detection coil;
Equipped with a computer,
An eddy current flaw detection system that detects surface flaws and back surface flaws of an object to be inspected,
The computer includes:
storing a first reference range and a second reference range preset in a coordinate system whose coordinates are the phase angle of the detection signal of the first detection coil and the phase angle of the detection signal of the second detection coil;
Calculating a phase angle for the detection signal of the first detection coil acquired by the flaw detection device, and calculating a phase angle for the detection signal of the second detection coil acquired by the flaw detection device,
Depending on whether the calculated phase angle of the detection signal of the first detection coil and the phase angle of the detection signal of the second detection coil are within the first reference range, the detection signal corresponds to a surface flaw signal. The detection method is determined based on whether the phase angle of the detection signal of the first detection coil and the phase angle of the detection signal of the second detection coil that are calculated are within the second reference range. Determine whether the signal corresponds to a backside flaw signal,
An eddy current flaw detection system characterized by outputting the determination results. 請求項１に記載の渦電流探傷システムにおいて、
前記コンピュータは、高周波数の交流信号を前記励磁コイルに印加した場合の前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角が前記第１基準範囲内にあるか否かにより、前記検出信号が表面きず信号に相当するか否かを判定すると共に、低周波数の交流信号を前記励磁コイルに印加した場合の前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角が前記第２基準範囲内にあるか否かにより、前記検出信号が裏面きず信号に相当するか否かを判定することを特徴とする渦電流探傷システム。 The eddy current flaw detection system according to claim 1,
The computer is configured such that when a high-frequency AC signal is applied to the excitation coil, a phase angle of a detection signal of the first detection coil and a phase angle of a detection signal of the second detection coil are within the first reference range. Whether or not the detection signal corresponds to a surface flaw signal is determined, and the phase angle of the detection signal of the first detection coil when a low frequency AC signal is applied to the excitation coil and the An eddy current flaw detection system, characterized in that it is determined whether the detection signal corresponds to a backside flaw signal based on whether a phase angle of the detection signal of the second detection coil is within the second reference range. 請求項１に記載の渦電流探傷システムにおいて、
前記コンピュータは、前記検出信号が裏面きず信号に相当すると判定した場合に、演算された前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角のうちの少なくとも一方に基づき、前記渦電流プローブに対向する前記検査対象物の表面と前記裏面きずの間の残肉の厚さを推定することを特徴とする渦電流探傷システム。 The eddy current flaw detection system according to claim 1,
When the computer determines that the detection signal corresponds to a backside flaw signal, the computer calculates at least one of the calculated phase angle of the detection signal of the first detection coil and the calculated phase angle of the detection signal of the second detection coil. An eddy current flaw detection system for estimating the thickness of remaining thickness between the front surface of the object to be inspected facing the eddy current probe and the flaw on the back surface based on the above. 少なくとも１つの励磁コイル、前記励磁コイルに対し一方側に配置された第１検出コイル、及び前記励磁コイルに対し他方側に配置された第２検出コイルを有する渦電流プローブと、
前記励磁コイルに励磁信号を印加すると共に、前記第１検出コイルの検出信号及び前記第２検出コイルの検出信号を取得する探傷装置とを用いて、
検査対象物の表面きず及び裏面きずを検出する渦電流探傷方法であって、
前記探傷装置で取得された前記第１検出コイルの検出信号に対して位相角を演算すると共に、前記探傷装置で取得された前記第２検出コイルの検出信号に対して位相角を演算し、
前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角を座標とする座標系にて予め設定された第１基準範囲内に、演算された前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角があるか否かにより、前記検出信号が表面きず信号に相当するか否かを判定すると共に、前記座標系にて予め設定された第２基準範囲内に、演算された前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角があるか否かにより、前記検出信号が裏面きず信号に相当するか否かを判定することを特徴とする渦電流探傷方法。 an eddy current probe having at least one excitation coil, a first detection coil disposed on one side with respect to the excitation coil, and a second detection coil disposed on the other side with respect to the excitation coil;
Using a flaw detection device that applies an excitation signal to the excitation coil and acquires a detection signal of the first detection coil and a detection signal of the second detection coil,
An eddy current flaw detection method for detecting surface flaws and back flaws of an object to be inspected,
Calculating a phase angle for the detection signal of the first detection coil acquired by the flaw detection device, and calculating a phase angle for the detection signal of the second detection coil acquired by the flaw detection device,
The first detection coil is calculated within a first reference range preset in a coordinate system whose coordinates are the phase angle of the detection signal of the first detection coil and the phase angle of the detection signal of the second detection coil. It is determined whether or not the detection signal corresponds to a surface flaw signal based on the phase angle of the detection signal of the second detection coil and the phase angle of the detection signal of the second detection coil. Depending on whether the calculated phase angle of the detection signal of the first detection coil and the phase angle of the detection signal of the second detection coil are within the calculated second reference range, the detection signal becomes a backside flaw signal. An eddy current flaw detection method characterized by determining whether or not they correspond. 請求項４に記載の渦電流探傷方法において、
高周波数の交流信号を前記励磁コイルに印加した場合の前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角が前記第１基準範囲内にあるか否かにより、前記検出信号が表面きず信号に相当するか否かを判定すると共に、低周波数の交流信号を前記励磁コイルに印加した場合の前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角が前記第２基準範囲内にあるか否かにより、前記検出信号が裏面きず信号に相当するか否かを判定することを特徴とする渦電流探傷方法。 In the eddy current flaw detection method according to claim 4,
Depending on whether the phase angle of the detection signal of the first detection coil and the phase angle of the detection signal of the second detection coil are within the first reference range when a high frequency AC signal is applied to the excitation coil. , determining whether or not the detection signal corresponds to a surface flaw signal, and determining the phase angle of the detection signal of the first detection coil and the second detection coil when a low frequency AC signal is applied to the excitation coil. An eddy current flaw detection method, characterized in that it is determined whether the detection signal corresponds to a backside flaw signal based on whether a phase angle of the detection signal is within the second reference range. 請求項４に記載の渦電流探傷方法において、
前記検出信号が裏面きず信号に相当すると判定した場合に、演算された前記第１検出コイルの検出信号の位相角及び前記第２検出コイルの検出信号の位相角のうちの少なくとも一方に基づき、前記渦電流プローブに対向する前記検査対象物の表面と前記裏面きずの間の残肉の厚さを推定することを特徴とする渦電流探傷方法。 In the eddy current flaw detection method according to claim 4,
When it is determined that the detection signal corresponds to a backside flaw signal, the calculated An eddy current flaw detection method characterized by estimating the thickness of remaining thickness between the surface of the inspection object facing an eddy current probe and the flaw on the back surface.
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