JP7174600B2 - Eddy current flaw detection system and eddy current flaw detection method - Google Patents

Description

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

Patent Document 1 discloses an eddy current flaw detection system that includes 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 the excitation coil and the detection coil, and one second as the excitation coil and the detection coil. A second mutual induction flaw detection mode (Y scan) in which one coil and one second coil are selected and controlled is executed. The eddy current flaw detector applies an excitation current to an excitation coil to generate a magnetic field in each flaw detection mode, thereby inducing eddy currents in the object. If there is a defect (flaw) in the object, the eddy current changes, so the change in the impedance of the detection coil caused by the change in the eddy current is acquired as a detection signal.

The computer calculates the detection signal based on the phase angle of the first detection signal obtained in the first mutual induction flaw detection mode and the phase angle of the second detection signal obtained in the second mutual induction flaw detection mode. is a defect signal (flaw signal). 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 A signal generated by leaving 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 2009-019909 A

In the prior art 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 defective signal is determined based on the difference in phase angle between them. determine what However, depending on the extending direction of the defect, the amplitude of the first detection signal or the amplitude of the second detection signal may be below the level. More specifically, for example, the defect extends so as to be perpendicular to the alignment direction of the excitation coil and the detection coil selected in the first mutual induction flaw detection mode (that is, the alignment direction of the two first coils). If present, the amplitude of the first detection signal may be less than the level because the change in eddy currents is small. Also, for example, it is perpendicular to the alignment direction of the excitation coils and detection coils selected in the second mutual induction flaw detection mode (that is, the alignment direction of one first coil and one second coil). If the defect extends like this, the amplitude of the second detection signal may be less than the level because the change in eddy current is small. In such cases, it becomes difficult to identify the defective signal.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to provide an eddy current flaw detection system and an eddy current flaw detection method that can identify a flaw signal regardless of the extension direction of the flaw. be.

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. a flaw detection probe, an eddy current flaw detector that selectively controls the plurality of first coils and the plurality of second coils, and the detection signal is a defect signal based on a detection signal obtained by the eddy current flaw detector An eddy current flaw detection system comprising a control device for determining whether the eddy current flaw detection device selects two first coils or two second coils as an excitation coil and a detection coil and a second mutual induction testing mode for selecting and controlling one first coil and one second coil as excitation coils and detection coils, and at least A self-inductive flaw detection mode in which either 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.

1 is a block diagram showing the configuration of an eddy current flaw detection system in one embodiment of the present invention; FIG. 1 is a schematic diagram showing the structure of a flaw detection probe in one embodiment of the present invention; FIG. 1 is a top view showing the structure of a scanning device in one embodiment of the present invention; FIG. FIG. 4 is a side view seen from the direction of arrow IV in FIG. 3; 4 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. FIG. 4 is a diagram for explaining a first mutual induction flaw detection mode in one embodiment of the present invention; FIG. 5 is a diagram for explaining a second mutual induction flaw detection mode in one embodiment of the present invention; FIG. 4 is a diagram for explaining a self-guided flaw detection mode in one embodiment of the present invention; 4 is a flow chart showing the procedure of signal identification processing of the control device in one embodiment of the present invention. FIG. 10 is a diagram for explaining a self-guided flaw detection mode in a modified example of the present invention;

One 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 this embodiment. 3 is a top view showing the structure of the scanning device in this embodiment, and FIG. 4 is a side view seen from the direction of arrow IV in FIG. Note that illustration of rails and encoders is omitted in FIG. 4 for the sake of 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 a test object 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 4 (for example, a computer) that controls the scanning device 2 and the eddy current flaw detector 3 and processes detection signals obtained by the eddy current flaw detector 3; It comprises a storage device 5 (eg a hard disk) connected to the device 4 and a display device 6 (eg a display).

The flaw detection probe 1 includes a flexible substrate 7, and a plurality of (eleven in this embodiment) first coils 8a to 8k arranged in a first row in the longitudinal direction of the substrate 7 (vertical direction in FIG. 2). , and a plurality of (ten in this embodiment) second coils 9a to 9j arranged in a second row parallel to the first row, the first coils 8a to 8h and the second coils 9a to 9j are arranged in a zigzag pattern (triangular lattice pattern). The axial directions of the first coils 8a to 8h and the second coils 9a to 9j are perpendicular to the substrate .

The scanning device 2 includes a pedestal 10 on which a subject S is placed, rails 11 provided on the pedestal 10, a moving unit 12 that holds the flaw detection probe 1 and moves along the rails 11, and a moving unit 12. (that is, the movement amount of the flaw detection probe 1). The moving unit 12 includes a running wheel (not shown) arranged on the rail 11, an electric motor (not shown) that rotates the running wheel, and an arm 15 that holds the flaw detection probe 1 via a cushioning material 14. , and a mechanism (not shown) for adjusting the position of the arm 15 in the vertical direction in FIG. By adjusting the position of the arm 15, the pressing force of the flaw detection probe 1 against the surface of the test object S can be adjusted.

The scanning device 2 drives the electric motor of the moving unit 12 according to a movement command from the control device 4 to move the flaw detection probe 1 . Also, 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 induction flaw detection mode, a second mutual induction flaw detection mode, and a self-induced flaw detection mode (details will be described later) in response to a flaw detection command from the control device 4. It is designed to 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 one of the first coils 8a to 8h and the second coils 9a to 9j to connect to the excitation control unit, and selects one of the first coils 8a to 8h and the second coils 9a to 9j. Either one is selected and connected to the detection control section. The excitation control section applies an excitation voltage to the coils connected via the multiplexer circuit to flow an excitation current. The detection control unit acquires impedance changes of the coils connected via the multiplexer circuit as detection signals.

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

In step S<b>101 , the control device 4 outputs a flaw detection command to the eddy current flaw detector 3 . Thereby, the eddy current flaw detector 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 the excitation coil and connects it to the excitation control section, and selects the first coil 8c as the detection coil and connects it to the detection control section. do. The excitation control section 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 through 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 control unit to the control device 4 together with selection information of the coil (here, the excitation coil as a representative).

After that, the eddy current flaw detector 3 selects the first coil 8b as the excitation coil, selects the first coil 8d as the detection coil, and performs similar control. After that, the eddy current flaw detector 3 selects the first coil 8c as the excitation coil, selects the first coil 8e as the detection coil, and performs similar control. After that, the eddy current flaw detector 3 selects the first coil 8d as the excitation coil, selects the first coil 8f as the detection coil, and performs similar control. Thereafter, the eddy current flaw detector 3 selects the first coil 8e as the excitation coil, selects the first coil 8g as the detection coil, and performs similar control.

After that, the eddy current flaw detector 3 selects the first coil 8f as the excitation coil, selects the first coil 8h as the detection coil, and performs similar control. After that, the eddy current flaw detector 3 selects the first coil 8g as the excitation coil, selects the first coil 8i as the detection coil, and performs similar control. Thereafter, the eddy current flaw detector 3 selects the first coil 8h as the excitation coil, selects the first coil 8j as the detection coil, and performs similar control. After that, the eddy current flaw detector 3 selects the first coil 8i as the excitation coil, selects the first coil 8k as the detection coil, and performs similar control.

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

Proceeding to 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 excitation coils and detection coils. More specifically, the multiplexer circuit of the eddy current flaw detector 3 first selects the first coil 8a as the excitation coil and connects it to the excitation control unit, and selects the second coil 9a as the detection coil and connects it to the detection control unit. do. The excitation control section 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 through 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 control unit to the control device 4 together with the selection information of the coil (excitation coil as a representative here).

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

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

After that, the eddy current flaw detector 3 selects the first coil 8f as the excitation coil, selects the second coil 9e as the detection coil, and performs similar control. After that, the eddy current flaw detector 3 selects the first coil 8f as the excitation coil, selects the second coil 9f as the detection coil, and performs similar control. Thereafter, the eddy current flaw detector 3 selects the first coil 8g as the excitation coil, selects the second coil 9f as the detection coil, and performs similar control. Thereafter, the eddy current flaw detector 3 selects the first coil 8g as the excitation coil, selects the second coil 9g as the detection coil, and performs similar control.

Thereafter, the eddy current flaw detector 3 selects the first coil 8h as the excitation coil, selects the second coil 9g as the detection coil, and performs similar control. Thereafter, the eddy current flaw detector 3 selects the first coil 8h as the excitation coil, selects the second coil 9h as the detection coil, and performs similar control. Thereafter, the eddy current flaw detector 3 selects the first coil 8i as the excitation coil, selects the second coil 9h as the detection coil, and performs similar control.

Thereafter, the eddy current flaw detector 3 selects the first coil 8i as the excitation coil, selects the second coil 9i as the detection coil, and performs similar control. After that, the eddy current flaw detector 3 selects the first coil 8j as the excitation coil, selects the second coil 9i as the detection coil, and performs similar control. After that, the eddy current flaw detector 3 selects the first coil 8j as the excitation coil, selects the second coil 9j as the detection coil, and performs similar control. After that, the eddy current flaw detector 3 selects the first coil 8k as the excitation coil, selects the second coil 9j as the detection coil, and performs similar control.

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

Proceeding to step S105, the eddy current flaw detector 3 executes a self-induction flaw detection mode in which two adjacent first coils are selected and controlled as 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 control section and the detection control section. The excitation control section 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 the impedance change of the first coils 8a and 8b connected through the 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 control unit to the control device 4 together with selection information of the coils (here, two excitation/detection coils).

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

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

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

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

At step S<b>108 , the control device 4 outputs a movement command to the scanning device 2 . Thereby, the scanning device 2 drives the electric motor of the moving unit 12 to move the flaw detection probe 1 . After that, the process returns to step S101 and repeats the above procedure.

The control device 4 performs 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. Details thereof will be described with reference to FIG. FIG. 9 is a flowchart showing the procedure of 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 having the same position information of the flaw detection probe 1 and the same coil selection information.

In step S201, the control device 4 determines whether or not the amplitude of the first detection signal is equal to or greater than a preset level. If the amplitude of the first detection signal is equal to or higher than the level, the determination in step S201 becomes YES, and the process proceeds to step S202. In step S202, the control device 4 determines whether 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 do. If 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 (where there are two second detection signals, If both of those amplitudes are equal to or higher than the level, it is determined whether or not the larger one of the two calculated differences is equal to or less than a predetermined value. If the aforementioned difference is equal to or less than a predetermined value (for example, 20 degrees), the determination in step S203 is YES, and the process proceeds to step S204. At step S204, the 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 flaw detection position information calculated from these information).

When the difference mentioned above exceeds a predetermined value, determination of step S203 becomes NO and moves 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 flaw detection position information calculated from these information).

If the amplitude of the first detection signal is less than the level, the determination in step S201 is NO, and the process proceeds to step S206. Alternatively, if the amplitude of the second detection signal is less than the level, the determination in step S202 is NO, and the process proceeds to step S206. In step S206, the control device 4 determines whether or not the amplitude of the third detection signal is equal to or higher than the level. If the amplitude of the third detection signal is equal to or higher than the level, the determination in step S206 becomes YES, and the process proceeds to step S205. In step S205, the control device 4 determines that the detection signal is the 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 flaw detection position information calculated from these information).

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

Next, the effects of this embodiment will be described.

Assume that the object to be inspected S has a defect. Although the amplitude of the third detection signal obtained in the self-induced flaw detection mode is large regardless of the extension direction of the defect, the amplitude of the first detection signal obtained in the first mutual induction flaw detection mode and the first detection signal The amplitude of the second detection signal obtained in the two mutual induction flaw detection modes becomes significantly smaller depending on the extending direction of the defect.

More specifically, for example, if the defect extends perpendicular to the direction in which the two first coils are arranged 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 below the level. Further, for example, when a defect extends perpendicular to the direction in which one first coil and one second coil are arranged in the second mutual induction flaw detection mode, 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 the defect signal or the lift-off signal only with the first detection signal or the second detection signal. Further, 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 this embodiment determines whether the detection signal is the defect signal or the 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 or not it is a defective signal. Even if at least one of the amplitude of the first detection signal and the amplitude of the second detection signal is below the level, if the amplitude of the third detection signal is above the level, the detection signal is determined to be a defect 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 defective 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, it is not limited to this, and modifications can be made without departing from the gist and technical idea of the present invention. That is, the control device 4, for example, determines that the phase angle of the first detection signal is in a preset first range (specifically, a predetermined range including, for example, 90 degrees), and the second detection signal is in a preset second range (specifically, for example, a predetermined range including 230 degrees), or the phase angle of the first detection signal is in the second range and the 2, the detection signal may be determined to be a defect signal when the phase angle of the detection signal is within the first range.

Further, in the above-described embodiment, the first mutual induction flaw detection mode is described as an example in which two first coils are selected and controlled as the excitation coil and the detection coil, but the present invention is not limited to this. Modifications are possible without departing from the gist and technical idea of the present invention. That is, the first mutual induction flaw detection mode may be controlled by selecting two second coils as the excitation coil and the detection coil.

In the above-described embodiment, the self-induction flaw detection mode has been described by taking as an example a case in which two adjacent first coils are selected and controlled as two excitation/detection coils, but the present invention is not limited to this. , modifications are possible without departing from the gist and technical idea of the present invention. That is, in the self-induction flaw detection mode, two adjacent second coils may be selected and controlled as two excitation/detection coils, or one adjacent first coil and one first coil may be controlled. 2 coils may be selected and controlled. Also, the self-induction flaw detection mode may be controlled by selecting, for example, one first coil or one second coil as one excitation/detection coil (see FIG. 10). In the self-induction flaw detection mode, as three or more excitation/detection coils, for example, three or more of the first coils 8a to 8k and the second coils 9a to 9j may be selected and controlled. good.

Further, in the above-described embodiment, the flaw detection probe 1 has been described as an example in which the first coils 8a to 8k and the second coils 9a to 9j are arranged in a zigzag pattern (triangular lattice pattern). Modifications are possible without departing from the gist and technical idea of the present invention. That is, the flaw detection probe 1 may have the first coils 8a to 8k and the second coils 9a to 9j arranged in a square lattice.

In the above embodiment, the eddy current flaw detection system has been described as an example in which the scanning device 2 moves the flaw detection probe 1 along the surface of the object. And modifications are possible within a range not deviating from the technical idea. That is, for example, the inspector may hold the flaw detection probe 1 and place it on the surface of the subject.

1 flaw detection probe 3 eddy current flaw detector 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 that selectively controls the plurality of first coils and the plurality of second coils;
An eddy current flaw detection system comprising a control device for determining whether the detection signal is a defect signal based on the detection signal obtained by the eddy current flaw detection device,
The eddy current flaw detector,
A first mutual induction 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 flaw detection mode in which one first coil and one second coil are selected and controlled as the excitation coil and the detection coil;
and a self-induction flaw detection mode for selecting and controlling any one of the plurality of first coils and the plurality of second coils as at least one excitation/detection coil. flaw detection system. In 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 greater than a preset level. determining 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 determining that the detection signal is a defect signal when the amplitude of the third detection signal obtained in the self-induced flaw detection mode is equal to or greater than the level. system. In the eddy current flaw detection system according to claim 1,
The self-induction flaw detection mode includes two excitation/detection coils, two adjacent first coils, two adjacent second coils, or one adjacent first coil and one second coil. An eddy current flaw detection system characterized by selecting and controlling two coils. Using 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,
selectively controlling the plurality of first coils and the plurality of second coils;
An eddy current flaw detection method for determining whether the detection signal is a defect signal based on the obtained detection signal,
A first mutual induction 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 flaw detection mode in which one first coil and one second coil are selected and controlled as the excitation coil and the detection coil;
and a self-induction flaw detection mode for selecting and controlling any one of the plurality of first coils and the plurality of second coils as at least one excitation/detection coil. flaw detection method. In 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 greater than a preset level. determining 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 determining that the detection signal is a defect signal when the amplitude of the third detection signal obtained in the self-induced flaw detection mode is equal to or greater than the level. Method. In the eddy current flaw detection method according to claim 4,
The self-induction flaw detection mode includes two excitation/detection coils, two adjacent first coils, two adjacent second coils, or one adjacent first coil and one second coil. An eddy current flaw detection method characterized by selecting and controlling two coils.

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