JP2020079747A - Eddy current flaw detection system and eddy current flaw detection method - Google Patents

Abstract

To provide an eddy current flaw detection system and an eddy current flaw detection method that can discriminate a defect signal without reference to an extending direction of a defect.SOLUTION: An eddy current flaw detection system comprises a flaw detection probe 1, an eddy current flaw detection device 3, and a control device 4. The flaw detection probe 1 has first coils 8a to 8k which are arranged in a first array and second coils 9a - 9j which are arranged in a second array parallel with the first array. The eddy current flaw detection device 3 selectively controls the first coils 8a to 8k and the second coils 9a to 9j to execute a first mutual induction type flaw detection mode, a second mutual induction type flaw detection mode, and a self-induction type flaw detection mode. The control device 4 determines whether or not a detection signal is a defect signal based upon a detection signal obtained by the eddy current flaw detection device 3.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an eddy current flaw detection system and an eddy current flaw detection method using a multi-coil probe.

  Patent Document 1 discloses an eddy current flaw detection system including a flaw detection probe (multi-coil probe), an eddy current flaw detection device, and a computer. The flaw detection probe has a plurality of first coils arranged in a first row and a plurality of second coils arranged in a second row parallel to the first row.

  The eddy current flaw detector has a first mutual induction flaw detection mode (X scan) in which two first coils are selected and controlled as an excitation coil and a detection coil, and one first excitation coil and a detection coil. A second mutual induction type flaw detection mode (Y scan) in which one coil and one second coil are selected and controlled is executed. In each flaw detection mode, the eddy current flaw detection apparatus causes an excitation current to flow through the excitation coil to generate a magnetic field and induce an eddy current in the subject. Since the eddy current changes if the subject has a defect (scratch), the change in the impedance of the detection coil due to the change in the eddy current is acquired as a detection signal.

  The computer detects the detection signal based on the phase angle of the first detection signal obtained in the first mutual induction type flaw detection mode and the phase angle of the second detection signal obtained in the second mutual induction type flaw detection mode. Is a defect signal (a flaw signal). More specifically, if the difference between the phase angle of the first detection signal and the phase angle of the second detection signal is a predetermined value (for example, 20 degrees) or less, the detection signal is a lift-off signal (specifically, the flaw detection probe It is determined that the signal is a signal generated by being separated from the surface of the subject. On the other hand, if the difference between the phase angle of the first detection signal and the phase angle of the second detection signal exceeds a predetermined value, it is determined that the detection signal is a defect signal.

JP, 2009-0199009, A

  In the conventional technique described in Patent Document 1, if the amplitude of the first detection signal and the amplitude of the second detection signal are equal to or higher than the level, whether the detection signal is a defect signal based on the difference between their phase angles. Determine whether However, the amplitude of the first detection signal or the amplitude of the second detection signal may be less than the level depending on the extending direction of the defect. More specifically, for example, the defect extends so as to be perpendicular to the direction in which the exciting coil and the detection coil selected in the first mutual induction flaw detection mode are arranged (that is, the direction in which the two first coils are arranged). If so, the change in the eddy current is small, so that the amplitude of the first detection signal may be less than the level. Further, for example, it is perpendicular to the arrangement direction of the exciting coil and the detection coil selected in the second mutual induction flaw detection mode (that is, the arrangement direction of one first coil and one second coil). As described above, when the defect extends, the change of the eddy current becomes small, so that the amplitude of the second detection signal may be less than the level. In such a case, it becomes difficult to identify the defective signal.

  The present invention has been made in view of the above matters, and an object thereof is to provide an eddy current flaw detection system and an eddy current flaw detection method capable of identifying a defect signal regardless of the extending direction of the defect. is there.

  To achieve the above object, the present invention has a plurality of first coils arranged in a first row and a plurality of second coils arranged in a second row parallel to the first row. The flaw detection probe, the eddy current flaw detector for selectively controlling the plurality of first coils and the plurality of second coils, and the detection signal based on the detection signal obtained by the eddy current flaw detector An eddy current flaw detection system including a control device for determining whether or not the first eddy current flaw detection apparatus selects two first coils or two second coils as an excitation coil and a detection coil. At least a first mutual induction type flaw detection mode controlled by the following: a second mutual induction type flaw detection mode in which one first coil and one second coil are selected and controlled as an exciting coil and a detection coil; A self-guided flaw detection mode in which any one of the plurality of first coils and the plurality of second coils is selected and controlled as one excitation/detection coil is executed.

  According to the present invention, a defect signal can be identified regardless of the extending direction of the defect.

It is a block diagram showing the composition of the eddy current flaw detection system in one embodiment of the present invention. It is a schematic diagram showing the structure of the flaw detection probe in one embodiment of the present invention. It is a top view showing the structure of the scanning device in one Embodiment of this invention. It is the side view seen from the arrow IV direction of FIG. It is a flow chart showing the procedure of flaw detection control of the eddy current flaw detection system in one embodiment of the present invention. It is a figure for demonstrating the 1st mutual induction type flaw detection mode in one Embodiment of this invention. It is a figure for demonstrating the 2nd mutual induction type flaw detection mode in one Embodiment of this invention. It is a figure for explaining the self-guided flaw detection mode in one embodiment of the present invention. It is a flow chart showing a procedure of signal discriminating processing of a control device in one embodiment of the present invention. It is a figure for demonstrating the self-guided flaw detection mode in the modification of this invention.

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of an eddy current flaw detection system according to this embodiment. FIG. 2 is a schematic diagram showing the structure of the flaw detection probe in the present embodiment. FIG. 3 is a top view showing the structure of the scanning device according to the present embodiment, and FIG. 4 is a side view seen from the direction of arrow IV in FIG. Note that, in FIG. 4, the rails and the encoder are not shown for convenience.

  The eddy current flaw detection system of the present embodiment includes a flaw detection probe 1 (multi-coil probe), a scanning device 2 that moves the flaw detection probe 1 along the surface of the subject S, and a coil of the flaw detection probe 1 (details will be described later). An eddy current flaw detector 3 that selectively controls, a controller 2 (for example, a computer) that controls the scanning device 2 and the eddy current flaw detector 3, and processes a detection signal obtained by the eddy current flaw detector 3. A storage device 5 (for example, a hard disk) and a display device 6 (for example, a display) connected to the device 4 are provided.

  The flaw detection probe 1 includes a flexible substrate 7 and a plurality of (11 in the present embodiment) first coils 8a to 8k arranged in a first row in the longitudinal direction of the substrate 7 (vertical direction in FIG. 2). , A plurality of (10 in the present embodiment) second coils 9a to 9j arranged as a second row parallel to the first row, and the first coils 8a to 8h and the second coils 9a to 9j. Are arranged in a staggered pattern (triangular grid). The axial directions of the first coils 8a to 8h and the second coils 9a to 9j are perpendicular to the substrate 7.

  The scanning device 2 holds a pedestal 10 on which the subject S is placed, a rail 11 provided on the pedestal 10, the flaw detection probe 1, and a moving unit 12 that moves along the rail 11 and a moving unit 12. And a wire-type encoder 13 for measuring the movement amount (that is, the movement amount of the flaw detection probe 1). The moving unit 12 includes traveling wheels (not shown) arranged on the rails 11, an electric motor (not shown) for rotating the traveling wheels, and an arm 15 for holding the flaw detection probe 1 via a cushioning material 14. , A mechanism (not shown) for adjusting the position of the arm 15 in the vertical direction of FIG. By adjusting the position of the arm 15, the pressing force of the flaw detection probe 1 against the surface of the subject S can be adjusted.

  The scanning device 2 drives the electric motor of the moving unit 12 according to the movement command from the control device 4 to move the flaw detection probe 1. In addition, the movement amount of the flaw detection probe 1 measured by the encoder 13 is output to the control device 4.

  The eddy current flaw detector 3 sequentially executes a first mutual guidance flaw detection mode, a second mutual guidance flaw detection mode, and a self guidance flaw detection mode (details will be described later) in response to a flaw detection command from the control device 4. It is supposed to do. More specifically, the eddy current flaw detector 3 has a multiplexer circuit, an excitation controller, and a detection controller. The eddy current flaw detector 3 controls the multiplexer circuit, the excitation controller, and the detection controller according to each flaw detection mode. The multiplexer circuit selects any one of the first coils 8a to 8h and the second coils 9a to 9j to connect to the excitation control unit, and also selects one of the first coils 8a to 8h and the second coils 9a to 9j. Select one of them and connect to the detection controller. The excitation control unit applies an excitation voltage to the coils connected via the multiplexer circuit and causes an excitation current to flow. The detection control unit acquires, as a detection signal, the impedance change of the coil connected via the multiplexer circuit.

  Next, flaw detection control of the eddy current flaw detection system in the present embodiment will be described. FIG. 5 is a flowchart showing the procedure of flaw detection control of the eddy current flaw detection system in the present embodiment. FIG. 6 is a diagram for explaining the first mutual induction type flaw detection mode in this embodiment. FIG. 7 is a diagram for explaining the second mutual induction type flaw detection mode in this embodiment. FIG. 8 is a diagram for explaining the self-guided flaw detection mode in this embodiment.

  In step S101, the control device 4 outputs a flaw detection command to the eddy current flaw detection device 3. As a result, the eddy current flaw detection apparatus 3 executes the first mutual induction flaw detection mode in which the two first coils are selected and controlled as the excitation coil and the detection coil. More specifically, the multiplexer circuit of the eddy current flaw detector 3 first selects the first coil 8a as an excitation coil and connects it to the excitation controller, and selects the first coil 8c as a detection coil and connects it to the detection controller. To do. The excitation control unit applies an excitation voltage to the first coil 8a connected via the multiplexer circuit to flow an excitation current. The detection control unit acquires the impedance change of the first coil 8c connected via the multiplexer circuit as a detection signal (hereinafter, referred to as a first detection signal). Then, the eddy current flaw detector 3 outputs the first detection signal acquired by the detection controller together with the selection information of the coil (excitation coil as a representative here) to the controller 4.

  After that, the eddy current flaw detector 3 selects the first coil 8b as the exciting coil and the first coil 8d as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8c as the exciting coil and the first coil 8e as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8d as the exciting coil and the first coil 8f as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8e as the exciting coil and the first coil 8g as the detecting coil, and performs the same control.

  After that, the eddy current flaw detector 3 selects the first coil 8f as the exciting coil and the first coil 8h as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8g as the exciting coil and the first coil 8i as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8h as the exciting coil and the first coil 8j as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8i as the exciting coil and the first coil 8k as the detecting coil, and performs the same control.

  In step S102, the control device 4 stores the first detection signal obtained in the first mutual induction flaw detection mode in the storage device 5 in association with the position information of the flaw detection probe 1 and the coil selection information. ..

  In step S103, the eddy current flaw detector 3 executes the second mutual induction flaw detection mode in which one first coil and one second coil are selected and controlled as the excitation coil and the detection coil. More specifically, the multiplexer circuit of the eddy current flaw detector 3 first selects the first coil 8a as an excitation coil and connects it to the excitation controller, and selects the second coil 9a as a detection coil and connects it to the detection controller. To do. The excitation control unit applies an excitation voltage to the first coil 8a connected via the multiplexer circuit to flow an excitation current. The detection control unit acquires the impedance change of the second coil 9a connected via the multiplexer circuit as a detection signal (hereinafter, referred to as a second detection signal). Then, the eddy current flaw detector 3 outputs the second detection signal acquired by the detection controller together with the selection information of the coil (excitation coil as a representative here) to the controller 4.

  After that, the eddy current flaw detector 3 selects the first coil 8b as the exciting coil and the second coil 9a as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8b as the exciting coil and the second coil 9b as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8c as the exciting coil and the second coil 9b as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8c as the exciting coil and the second coil 9c as the detecting coil, and performs the same control.

  After that, the eddy current flaw detector 3 selects the first coil 8d as the exciting coil and the second coil 9c as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8d as the exciting coil and the second coil 9d as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8e as the exciting coil and the second coil 9d as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8e as the exciting coil and the second coil 9e as the detecting coil, and performs the same control.

  After that, the eddy current flaw detector 3 selects the first coil 8f as the exciting coil and the second coil 9e as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8f as the exciting coil and the second coil 9f as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8g as the exciting coil and the second coil 9f as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8g as the exciting coil and the second coil 9g as the detecting coil, and performs the same control.

  After that, the eddy current flaw detector 3 selects the first coil 8h as the exciting coil and the second coil 9g as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8h as the exciting coil and the second coil 9h as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8i as the exciting coil and the second coil 9h as the detecting coil, and performs the same control.

  After that, the eddy current flaw detector 3 selects the first coil 8i as the exciting coil and the second coil 9i as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8j as the exciting coil and the second coil 9i as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8j as the exciting coil and the second coil 9j as the detecting coil, and performs the same control. After that, the eddy current flaw detector 3 selects the first coil 8k as the exciting coil and the second coil 9j as the detecting coil, and performs the same control.

  In step S104, the control device 4 stores the second detection signal obtained in the second mutual induction type flaw detection mode in the storage device 5 in association with the position information of the flaw detection probe 1 and the coil selection information. ..

  In step S105, the eddy current flaw detector 3 executes the self-induction flaw detection mode in which two adjacent first coils are selected and controlled as the two excitation/detection coils. More specifically, the multiplexer circuit of the eddy current flaw detector 3 first selects the first coils 8a and 8b as excitation/detection coils and connects them to the excitation controller and the detection controller. The excitation control unit applies an excitation voltage to the first coils 8a and 8b connected via a multiplexer circuit to flow an excitation current. The detection control unit acquires a change in impedance of the first coils 8a and 8b connected via a multiplexer circuit as a detection signal (hereinafter, referred to as a third detection signal). Then, the eddy current flaw detector 3 outputs the third detection signal acquired by the detection controller together with the selection information of the coil (here, two excitation/detection coils) to the controller 4.

  After that, the eddy current flaw detector 3 selects the first coils 8b and 8c as the excitation/detection coils and performs the same control. After that, the eddy current flaw detector 3 selects the first coils 8c and 8d as the excitation/detection coils and performs the same control. After that, the first coils 8d and 8e are selected as the excitation/detection coils, and the same control is performed. After that, the eddy current flaw detector 3 selects the first coils 8e and 8f as the excitation/detection coils and performs the same control. After that, the eddy current flaw detector 3 selects the first coils 8f and 8g as the excitation/detection coils and performs the same control.

  After that, the eddy current flaw detector 3 selects the first coils 8g and 8h as the excitation/detection coils and performs the same control. After that, the first coils 8h and 8i are selected as the excitation/detection coils, and the same control is performed. After that, the eddy current flaw detector 3 selects the first coils 8i and 8j as the excitation/detection coils and performs the same control. After that, the eddy current flaw detector 3 selects the first coils 8j and 8k as the excitation/detection coils and performs the same control.

  In step S106, the control device 4 stores the third detection signal obtained in the self-guided flaw detection mode in the storage device 5 in association with the position information of the flaw detection probe 1 and the coil selection information.

  In step S107, the control device 4 determines whether the flaw detection is completed. For example, it is determined that the flaw detection is completed when the end signal is input by the operation of the inspector or when the movement amount of the flaw detection probe 1 measured by the encoder reaches the set value. If it is not determined that the flaw detection is completed, the process proceeds to step S108.

  In step S108, the control device 4 outputs a movement command to the scanning device 2. As a result, the scanning device 2 drives the electric motor of the moving unit 12 to move the flaw detection probe 1. Then, it returns to step S101 and repeats the above-mentioned procedure.

  The control device 4 performs the signal identification processing based on the first detection signal, the second detection signal, and the third signal stored in the storage device 5 as described above. The details will be described with reference to FIG. FIG. 9 is a flowchart showing the procedure of the signal identification processing of the control device in this embodiment.

  The control device 4 performs the following processing on the first detection signal, the second detection signal, and the third detection signal, which have the same position information of the flaw detection probe 1 and selection information of the coil.

  In step S201, control device 4 determines whether or not the amplitude of the first detection signal is equal to or higher than a preset level. When the amplitude of the first detection signal is equal to or higher than the level, the determination in step S201 is YES, and the process proceeds to step S202. In step S202, the control device 4 determines whether or not the amplitude of the second detection signal (however, if there are two second detection signals, the larger one of those amplitudes) is equal to or higher than the level. To do. When the amplitude of the second detection signal is equal to or higher than the level, the determination in step S202 becomes YES and the process proceeds to step S203.

  In step S203, the control device 4 calculates the difference between the phase angle of the first detection signal and the phase angle of the second detection signal, and the calculated difference (however, there are two second detection signals, When both the amplitudes are equal to or higher than the level, it is determined whether or not the larger one of the calculated two differences) is equal to or less than a predetermined value. When the difference is equal to or less than the predetermined value (for example, 20 degrees), the determination in step S203 is YES and the process proceeds to step S204. In step S204, control device 4 determines that the detection signal is the lift-off signal. Then, the determination result described above is stored in the storage device 5 in association with the position information of the flaw detection probe 1 and the coil selection information (or the flaw detection position information calculated from these pieces of information).

  If the difference exceeds the predetermined value, the determination in step S203 is NO, and the process proceeds to step S205. In step S205, the control device 4 determines that the detection signal is a defect signal (flaw signal). Then, the determination result described above is stored in the storage device 5 in association with the position information of the flaw detection probe 1 and the coil selection information (or the flaw detection position information calculated from these pieces of information).

  When the amplitude of the first detection signal is less than the level, the determination in step S201 becomes NO and the process proceeds to step S206. Alternatively, when the amplitude of the second detection signal is less than the level, the determination in step S202 becomes NO and the process proceeds to step S206. In step S206, control device 4 determines whether or not the amplitude of the third detection signal is equal to or higher than the level. When the amplitude of the third detection signal is equal to or higher than the level, the determination in step S206 is YES and the process proceeds to step S205. In step S205, control device 4 determines that the detection signal is a defect signal. Then, the determination result described above is stored in the storage device 5 in association with the position information of the flaw detection probe 1 and the coil selection information (or the flaw detection position information calculated from these pieces of information).

  The display device 6 performs flaw detection based on the defect signal stored in the storage device 5 and the position information of the flaw detection probe 1 and the coil selection information associated with the defect signal (or flaw detection position information calculated from these information). It is designed to display the results.

  Next, the function and effect of this embodiment will be described.

  It is assumed that the inspection body S has a defect. Although the amplitude of the third detection signal obtained in the self-guided flaw detection mode is large irrespective of the extending direction of the defect, the amplitude of the first detection signal and the first detection signal obtained in the first mutual-guided flaw detection mode are the same as those of the first detection signal. The amplitude of the second detection signal obtained in the two mutual induction type flaw detection mode becomes significantly smaller depending on the extending direction of the defect.

  More specifically, for example, when the defect extends so as to be perpendicular to the arrangement direction of the two first coils selected in the first mutual induction flaw detection mode, the change in eddy current is small. Therefore, the amplitude of the first detection signal may be less than the level. Further, for example, when the defect extends at right angles to the arrangement direction of the one first coil and the one second coil selected in the second mutual induction type flaw detection mode, the eddy current , The amplitude of the second detection signal may be less than the level.

  In such a case, it is not possible to determine whether the detection signal is a defect signal or a lift-off signal only with the first detection signal or the second detection signal. Moreover, it is not possible to determine whether the detection signal is the defect signal or the lift-off signal only with the third detection signal.

  Therefore, the control device 4 of the present embodiment determines whether the detection signal is a defect signal or a lift-off signal based on the first detection signal, the second detection signal, and the third detection signal. Specifically, when the amplitude of the first detection signal and the amplitude of the second detection signal are equal to or higher than the level, the detection signal is detected based on the phase angle of the first detection signal and the phase angle of the second detection signal. It is determined whether the signal is a defect signal. Even if at least one of the amplitude of the first detection signal and the amplitude of the second detection signal is less than the level, if the amplitude of the third detection signal is at least the level, the detection signal is a defective signal. judge. Therefore, the defect signal can be identified regardless of the extending direction of the defect.

  In the above embodiment, the control device 4 determines that the detection signal is a defect signal when the difference between the phase angle of the first detection signal and the phase angle of the second detection signal exceeds a predetermined value. Although the case has been described as an example, the present invention is not limited to this, and modifications can be made without departing from the spirit and technical idea of the present invention. That is, the control device 4 is, for example, in the first range (specifically, a predetermined range including 90 degrees) in which the phase angle of the first detection signal is set in advance, and Of the first detection signal is in the second range (specifically, a predetermined range including, for example, 230 degrees), or the phase angle of the first detection signal is in the second range, and If the phase angle of the second detection signal is in the first range, it may be determined that the detection signal is a defect signal.

  Further, in the above-described one embodiment, the first mutual induction flaw detection mode has been described by taking as an example the case where two first coils are selected and controlled as the exciting coil and the detecting coil, but the present invention is not limited to this. Modifications can be made without departing from the spirit and technical idea of the present invention. That is, in the first mutual induction flaw detection mode, two second coils may be selected and controlled as the excitation coil and the detection coil.

  Further, in the above-described one embodiment, the self-induction flaw detection mode has been described by taking as an example the case where two adjacent first coils are selected and controlled as the two excitation/detection coils, but the present invention is not limited to this. Modifications are possible without departing from the spirit and technical idea of the present invention. That is, in the self-guided flaw detection mode, two adjacent second coils may be selected and controlled as the two excitation/detection coils, or one adjacent first coil and one adjacent first coil may be controlled. Two coils may be selected and controlled. Further, in the self-guided flaw detection mode, for example, one first coil or one second coil may be selected and controlled as one excitation/detection coil (see FIG. 10). Further, in the self-guided flaw detection mode, even if three or more exciting/detecting coils are selected and controlled, for example, three or more coils of the first coils 8a to 8k and the second coils 9a to 9j are selected and controlled. Good.

  Further, in the above-described one embodiment, the flaw detection probe 1 has been described by taking as an example the case where the first coils 8a to 8k and the second coils 9a to 9j are arranged in a staggered pattern (triangular lattice pattern), but the present invention is not limited thereto. Without departing from the spirit and technical idea of the present invention, modifications can be made. That is, in the flaw detection probe 1, the first coils 8a to 8k and the second coils 9a to 9j may be arranged in a square lattice shape.

  Further, in the above-described one embodiment, the eddy current flaw detection system has been described by taking the case where the flaw detection probe 1 is provided with the scanning device 2 that moves along the surface of the subject as an example. Also, modifications can be made without departing from the technical idea. That is, for example, an inspector may grasp the flaw detection probe 1 and arrange it on the surface of the subject.

1 flaw detection probe 3 eddy current flaw detection device 4 control device 8a to 8k first coil 9a to 9j second coil

Claims (6)

A flaw detection probe having a plurality of first coils arranged in a first row and a plurality of second coils arranged in a second row parallel to the first row,
An eddy current flaw detector for selectively controlling the plurality of first coils and the plurality of second coils;
Based on the detection signal obtained by the eddy current flaw detection device, an eddy current flaw detection system comprising a control device for determining whether the detection signal is a defect signal,
The eddy current flaw detector is
A first mutual induction type flaw detection mode in which two first coils or two second coils are selected and controlled as the excitation coil and the detection coil;
A second mutual induction type flaw detection mode in which one first coil and one second coil are selected and controlled as the excitation coil and the detection coil;
An eddy current that executes a self-induction flaw detection mode in which any one of the plurality of first coils and the plurality of second coils is selected and controlled as at least one excitation/detection coil. Flaw detection system. The eddy current flaw detection system according to claim 1,
The control device is
The amplitude of the first detection signal obtained in the first mutual induction flaw detection mode and the amplitude of the second detection signal obtained in the second mutual induction flaw detection mode are equal to or higher than a preset level. In this case, it is determined whether the detection signal is a defect signal based on the phase angle of the first detection signal and the phase angle of the second detection signal,
At least one of the amplitude of the first detection signal obtained in the first mutual induction flaw detection mode and the amplitude of the second detection signal obtained in the second mutual induction flaw detection mode is less than the level. And when the amplitude of the third detection signal obtained in the self-guided flaw detection mode is equal to or higher than the level, it is determined that the detection signal is a defect signal. system. The eddy current flaw detection system according to claim 1,
In the self-induction flaw detection mode, two excitation/detection coils are used as two adjacent first coils, two adjacent second coils, or one adjacent first coil and one first coil. An eddy current flaw detection system characterized by selecting and controlling two coils. A flaw detection probe having a plurality of first coils arranged in a first row and a plurality of second coils arranged in a second row parallel to the first row is used,
Selectively controlling the plurality of first coils and the plurality of second coils,
Based on the obtained detection signal, an eddy current flaw detection method for determining whether the detection signal is a defect signal,
A first mutual induction type flaw detection mode in which two first coils or two second coils are selected and controlled as the excitation coil and the detection coil;
A second mutual induction type flaw detection mode in which one first coil and one second coil are selected and controlled as the excitation coil and the detection coil;
Eddy current characterized by executing a self-induced flaw detection mode in which any one of the plurality of first coils and the plurality of second coils is selected and controlled as at least one excitation/detection coil. Method of flaw detection. The eddy current flaw detection method according to claim 4,
The amplitude of the first detection signal obtained in the first mutual induction flaw detection mode and the amplitude of the second detection signal obtained in the second mutual induction flaw detection mode are equal to or higher than a preset level. In this case, it is determined whether the detection signal is a defect signal based on the phase angle of the first detection signal and the phase angle of the second detection signal,
At least one of the amplitude of the first detection signal obtained in the first mutual induction flaw detection mode and the amplitude of the second detection signal obtained in the second mutual induction flaw detection mode is less than the level. And when the amplitude of the third detection signal obtained in the self-guided flaw detection mode is equal to or higher than the level, it is determined that the detection signal is a defect signal. Method. The eddy current flaw detection method according to claim 4,
In the self-induction flaw detection mode, two excitation/detection coils are used as two adjacent first coils, two adjacent second coils, or one adjacent first coil and one first coil. An eddy current flaw detection method characterized by selecting and controlling two coils.

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