Eddy current testing apparatus and eddy current testing method

Abstract

An eddy-current flaw detection device (1) comprises: a probe (10) that detects a change of eddy current in the component surface (41) of an object (40) to be examined; and a control unit (23) that causes the probe (10) to scan the component surface (41) along a scanning path (P) crossing edges (45) of the component surface (41). The scanning path (P) includes a first scanning path (P1a) along which scanning is executed in a first direction from a first region (47) adjacent to an edge region (46) existing along the edges (45) of the component surface (41), crossing the edge region (46), to a region (50) outside the edges (45). The probe (10) executes scanning along the first scanning path (P1a), and detects a change of eddy current in the edge region (46).

Description

Technical Field

[0001] The present disclosure relates to an eddy current flaw detection device and an eddy current flaw detection method.

Background Art

[0002] The eddy current inspection system disclosed in Patent Document 1 below includes an eddy current probe and a computer coupled to the eddy current probe. The computer generates an original image of a component during a test, decomposes the original image into a plurality of images each including different spatial frequency components, and stores spatial frequency data including spatial frequency components corresponding to known eddy current flaw signals. Further, the computer selects from the plurality of images a plurality of images including a plurality of different spatial frequency components corresponding to known eddy current flaw signals based on the stored spatial frequency data. Further, the computer is configured to reconstruct at least one final image of the component using the selected plurality of images.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, eddy current testing has been used to detect scratches on the surface of metal parts. In eddy current testing, the surface of the part to be inspected is scanned with a probe, and changes in the eddy currents generated on that surface are detected. This makes it possible to detect scratches on the surface of the part. Here, it is known that an edge effect occurs, where the eddy currents generated on the surface of the part change when the magnetic field generated from the probe's coil crosses the edge of the part to be inspected, and an edge signal is detected. In addition, defect signals indicating defects such as cracks located near the edge were sometimes masked by the edge signal, making it difficult to detect those defects. For this reason, eddy current testing was sometimes performed by separating the inspection process for the surface near the edge from the inspection process for the surface other than the surface near the edge. In other words, there was a risk that the eddy current testing process would become complicated due to the edge effect. [Means for solving the problem]

[0005] The eddy current flaw detection apparatus according to this disclosure comprises a probe for detecting changes in eddy currents on the surface of a part to be inspected, and a control unit for causing the probe to scan the surface of the part along a scanning path that crosses the edge of the surface of the part, wherein the scanning path includes a first scanning path that scans the surface of the part from a first region adjacent to an edge region extending along the edge toward a region outside the edge, and the probe scans along the first scanning path and detects changes in the eddy currents in the edge region.

[0006] In the eddy current flaw detection apparatus described above, the scanning path may include a second scanning path that scans from a region outside the edge, across the edge, and toward the first region in a second direction, and the probe may scan along the second scanning path to detect changes in the eddy current in the first region.

[0007] The eddy current flaw detection apparatus described above includes a determination unit that determines a first region signal indicating a change in the eddy current in the first region, the first region signal including a first signal detected by scanning along the first scanning path and a second signal detected by scanning along the second scanning path, and the determination unit may determine the one with the higher intensity of the first signal and the second signal as the first region signal.

[0008] The eddy current testing method according to this disclosure involves scanning the surface of a part of an object to be inspected with a probe that detects changes in eddy currents on the part surface along a scanning path that crosses the edge of the part surface, the scanning path including a first scanning path that scans in a first direction from a first region adjacent to an edge region extending along the edge of the part surface toward a region outside the edge, and scanning along the first scanning path with the probe to detect changes in eddy currents in the edge region. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide an eddy current testing apparatus and an eddy current testing method that can perform eddy current testing more easily. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic perspective view showing an example of the overall configuration of an eddy current flaw detection apparatus according to an embodiment. [Figure 2] Figure 2 is a schematic perspective view showing an object to be inspected by the eddy current flaw detection apparatus according to the embodiment. [Figure 3] Figure 3 is a block diagram showing an example of the overall configuration of an eddy current flaw detection apparatus according to this embodiment. [Figure 4] Figure 4 is a schematic diagram showing the probe of the eddy current flaw detection apparatus according to the embodiment. [Figure 5] Figure 5 is a diagram illustrating the inspection process performed by the eddy current testing apparatus according to the embodiment, and is a schematic perspective view showing the positional relationship between the surface to be inspected by the eddy current testing and the probe. [Figure 6] Figure 6 is a diagram illustrating the first step of the edge inspection process performed in the eddy current flaw detection apparatus according to the embodiment, and is a schematic side view showing the positional relationship between the surface to be inspected for the eddy current flaw detection test and the probe. [Figure 7] Figure 7 is a diagram illustrating the second step of the edge inspection process performed in the eddy current flaw detection apparatus according to the embodiment, and is a schematic side view showing the positional relationship between the surface to be inspected for the eddy current flaw detection test and the probe. [Figure 8] Figure 8 is a diagram illustrating the third step of the edge inspection process performed in the eddy current flaw detection apparatus according to the embodiment, and is a schematic side view showing the positional relationship between the surface to be inspected for the eddy current flaw detection test and the probe. [Modes for carrying out the invention]

[0011] Several exemplary embodiments will be described below with reference to the drawings. Elements having the same function will be denoted by the same reference numerals, and redundant descriptions will be omitted.

[0012] In each figure, the X-axis direction is the direction in which the first slider 4a, described later, can move, and the positive and negative X-axis directions are collectively referred to simply as the "X-axis direction". The Y-axis direction is the direction in which the second slider 4b, described later, can move, and the positive and negative Y-axis directions are collectively referred to simply as the "Y-axis direction". The Z-axis direction is the direction in which the third slider 4c, described later, can move, and the positive and negative Z-axis directions are collectively referred to simply as the "Z-axis direction". Note that the positive Z-axis direction corresponds to upward, and the negative Z-axis direction corresponds to downward. Also, the X-axis direction, Y-axis direction, and Z-axis direction intersect with each other, or for example, they may be approximately orthogonal to each other. The θ-axis direction is the direction of rotation around axis A1, described later, and the positive and negative θ-axis directions are collectively referred to simply as the "θ-axis direction". The P-axis direction is the direction of rotation around the extension direction of the probe shaft 7, described later, and the positive and negative P-axis directions are collectively referred to simply as the "P-axis direction". The R-axis direction is the rotational direction around axis A2 of stage 6, which will be described later, and the positive R-axis direction and the negative R-axis direction together are simply referred to as the "R-axis direction".

[0013] The eddy current testing apparatus and method according to the embodiment can be used for eddy current testing. Eddy current testing can be used to inspect conductive objects for defects such as cracks. Eddy current testing is also called ET (Eddy current testing).

[0014] In eddy current testing, an excitation coil creates a magnetic field on the surface of the object being inspected, thereby generating eddy currents on that surface. The magnetic field induced by these eddy currents is then detected by a detection coil. If a defect exists on the surface of the object being inspected, the path of the eddy current changes due to the influence of the defect. As a result, the magnetic field induced by the eddy current changes. By detecting this change in the magnetic field with the detection coil, it is possible to determine whether or not a defect exists on the surface of the object being inspected. In other words, by detecting the change in eddy currents caused by the presence or absence of defects, the condition of the surface of the object being inspected can be examined.

[0015] First, an example of the inspection device 1 and the object to be inspected will be described with reference to Figures 1 and 2. The inspection device 1 is an eddy current flaw detection device for inspecting the surface 41 of a component. The component surface 41 is the surface of the component 40, which is the object to be inspected, and is the surface that is subject to eddy current flaw detection testing. The component surface 41 may be a part of the entire surface of the component 40. The inspection device 1 performs eddy current flaw detection testing to determine whether or not a defect exists on the component surface 41. Note that the structure of the inspection device 1 is not limited to the configuration exemplified in the figures, and the structure can be appropriately changed according to the shape, dimensions, installation location, type of component 40, etc.

[0016] As illustrated in Figure 1, the inspection device 1 comprises a frame 2 and a drive mechanism 3. The frame 2 is constructed, for example, by combining metal columns and beams. An upper surface 2a is formed on the upper part of the frame 2. Parts 40 (see Figure 2) can be placed on the upper surface 2a. The upper surface 2a may extend substantially parallel to the XY plane.

[0017] The component 40 illustrated in FIGS. 1 and 2 has a generally cylindrical shape as a whole. The component 40 is made of, for example, metal. When the component 40 is placed on the upper surface 2a, the central axis of the cylindrical shape may extend substantially parallel to the Z-axis direction. The component 40 has, for example, a body portion 42, a convex portion 43, and a slot 44.

[0018] The body portion 42 forms a part of the component 40 from the inner peripheral side to the outer peripheral side of the component 40. The convex portion 43 is disposed on the outer peripheral side portion of the body portion 42. That is, on the outer peripheral portion of the component 40, a plurality of convex portions 43 and a plurality of slots 44 are formed. The convex portion 43 is formed to extend radially outward from the body portion 42, and may extend in the vertical direction when the component 40 is placed on the upper surface 2a. Each of the plurality of convex portions 43 may be located on the circumference of the same circle centered on the axis A2 in a plan view, and each of the plurality of convex portions 43 may be formed to be spaced apart at a predetermined interval in the R-axis direction. A slot 44 is formed between two adjacent ones of the plurality of convex portions 43. The slot 44 is a groove that extends in the vertical direction when the component 40 is placed on the upper surface 2a. A plurality of slots 44 may be formed at a predetermined interval in the R-axis direction on the outer peripheral portion of the component 40. Note that the shape, dimensions, or posture of the component 40 is not limited to the example shown in the figure.

[0019] The slot 44 is defined by the outer peripheral surface 42a of the body portion 42 and the side surface 43a of the convex portion 43. The outer peripheral surface 42a is a surface that forms a part of the outer peripheral portion of the body portion 42. The side surface 43a is a surface that forms the portion of the convex portion 43 on the R-axis direction side.

[0020] The drive mechanism 3 is a mechanism that controls the position or posture of the probe 10 or the component 40 described later. The drive mechanism 3 may be disposed at a predetermined position on the upper surface 2a. Also, the drive mechanism 3 may have at least one of, for example, a first slider 4a, a second slider 4b, a third slider 4c, a holding member 5, and a stage 6.

[0021] The first slider 4a is a member that is movable in the X-axis direction in the region above the upper surface 2a. The first slider 4a may be a long, metal member that extends in the Y-axis direction. The first slider 4a may be configured to be movable in the X-axis direction by sliding along a rail that extends in the X-axis direction and is disposed on the upper surface 2a, for example.

[0022] The second slider 4b is a member that is movable in the Y-axis direction in the region above the upper surface 2a. The second slider 4b may be a long, metal member that extends in the Z-axis direction. The second slider 4b may be configured to move in the Y-axis direction on the first slider 4a by sliding along a rail that extends in the Y-axis direction and is disposed on the upper surface of the first slider 4a.

[0023] The third slider 4c is a member that is movable in the Z-axis direction in the region above the upper surface 2a. The third slider 4c may also be a member that extends in the X-axis direction. The third slider 4c may be configured to be movable in the Z-axis direction by sliding along a rail that extends in the Z-axis direction and is disposed on the second slider 4b. The third slider 4c is attached to the second slider 4b so as to protrude toward the positive X-axis direction from the X-axis positive side surface of the second slider 4b. A retaining member 5 may also be fixed to the X-axis positive end of the third slider 4c.

[0024] The holding member 5 holds the end of the probe shaft 7, and in the configuration illustrated in Figure 1, the probe shaft 7 extends from the holding member 5 in the negative Z-axis direction. A probe 10 (see Figure 4) is attached to the tip of the probe shaft 7 on the negative Z-axis side. In other words, the probe shaft 7 is a member that connects the holding member 5 and the probe 10. The holding member 5 may hold the probe shaft 7 so that it can rotate around its extending direction. This allows the holding member 5 to rotate the probe 10 in the P-axis direction. Alternatively, the holding member 5 may be fixed to the third slider 4c so that it can rotate around axis A1. This allows the holding member 5 to rotate in the θ-axis direction with axis A1 as the central axis. Axis A1 is an axis that extends in the X-axis direction.

[0025] Stage 6 is a member capable of supporting the component 40 and is disposed in a predetermined area of ​​the upper surface 2a. Stage 6 may also be rotatable about axis A2 as its central axis. That is, Stage 6 may support the component 40 so that it can rotate around axis A2. The axis A2 illustrated in Figure 1 is an axis extending in the Z-axis direction, but is not limited to this. For example, axis A2 may be inclined with respect to the Z-axis.

[0026] This drive mechanism 3 allows the position of the probe 10 in the X, Y, and Z axes to be adjusted, for example, by adjusting the positions of the first slider 4a, the second slider 4b, and the third slider 4c. Furthermore, the orientation of the coil 11 of the probe 10 (described later) can be adjusted by adjusting the rotation of the probe shaft 7 in the P axis direction. That is, the P axis direction corresponds to the rotational direction around the central axis of rotation of the probe 10. Additionally, the angle of the probe 10 with respect to the Z axis can be adjusted by adjusting the rotation of the holding member 5 in the θ axis direction. Moreover, with the component 40 fixed to the stage 6, the position of each part of the component 40 in the R axis direction can be adjusted by adjusting the rotation of the stage 6 around axis A2. In other words, the drive mechanism 3 allows the position or orientation of the probe 10 or each part of the component 40 to be set to any desired state. This enables more accurate eddy current testing to be performed in accordance with the shape of the component 40.

[0027] The structure of the drive mechanism 3 is not limited to the illustrated example. The structure of the drive mechanism 3 can be appropriately modified according to the shape, dimensions, installation location of the inspection device 1, the type of part 40, etc. Furthermore, the drive mechanism 3 can be adjusted in the X-axis, Y-axis, Z-axis, P-axis, θ-axis, and R-axis directions, but is not limited to these. The number of adjustable axes of the drive mechanism 3 can be appropriately changed according to the shape, dimensions, installation location of the inspection device 1, the type of part 40, etc.

[0028] Next, an example of the configuration of the inspection device 1 will be further described with reference to Figures 3 and 4. The inspection device 1 illustrated in Figure 3 comprises a probe 10 and a control unit 23. The control unit 23 constitutes part of the controller 20, which will be described later. The controller 20 may also include a determination unit 21.

[0029] First, let's describe the probe 10. The probe 10 is a module that scans the surface of an object to be inspected along a predetermined scanning path and detects changes in eddy currents on the surface along that scanning path. The probe 10 is connected to the drive mechanism 3 via the probe shaft 7. The probe 10 illustrated in the figure detects changes in eddy currents on the surface 41 of a part 40.

[0030] As illustrated in Figure 4, the probe 10 has a substantially cylindrical shape that extends in a direction parallel to the extending direction of the probe shaft 7. A coil 11 is disposed on the side of the probe 10. The coil 11 may also include an excitation coil 11a and a detection coil 11b. The excitation coil 11a is a coil for generating eddy currents on the surface of the object to be inspected. The detection coil 11b is a coil for detecting the magnetic field induced by the eddy currents.

[0031] In eddy current testing, the probe 10 scans a predetermined scanning path. At this time, an excitation coil 11a through which alternating current flows generates eddy currents on the surface of the object being inspected. If a defect such as a crack is present in the object being inspected, the eddy currents will change as a result. Consequently, the magnetic field induced by these eddy currents changes. By detecting this change in the magnetic field with the detection coil 11b, a signal indicating the change in eddy currents can be obtained.

[0032] In the example shown in Figure 4, the excitation coil 11a and the detection coil 11b are directly adjacent in the extending direction of the probe 10, and the detection coil 11b is located on the probe shaft 7 side of the excitation coil 11a. However, the position of the excitation coil 11a or the detection coil 11b on the probe 10 is not limited to the position shown in Figure 4, and may be changed as appropriate, for example, depending on the shape of the object to be inspected.

[0033] Next, the controller 20 will be described. The controller 20 illustrated in Figure 3 includes a control unit 23. The controller 20 is a unit that performs the processing necessary for eddy current testing. The controller 20 may be a general-purpose microcomputer equipped with, for example, a CPU (Central Processing Unit), memory, input / output unit, etc. A computer program containing default rules, commands, etc. for processing eddy current testing is installed in the memory of the microcomputer. By executing this computer program, the microcomputer can perform eddy current testing. The controller 20 may be installed, for example, in the inspection device 1.

[0034] The controller 20 controls the position or orientation of the probe 10 when performing eddy current testing with the inspection device 1. The controller 20 may also acquire a signal indicating the change in eddy current detected by the probe 10 and output information related to this signal to the display unit 26, which will be described later.

[0035] The control unit 23 can control the position or orientation of the probe 10 or the part 40. A drive mechanism 3 is connected to the control unit 23. The drive mechanism 3 sets the position or orientation of the probe 10 or the part 40 based on commands output from the control unit 23. For example, the control unit 23 outputs various control values ​​to the drive mechanism 3. The control values ​​output to the drive mechanism 3 are, for example, values ​​(signals) for controlling the position, orientation, or rotation of the first slider 4a, the second slider 4b, the third slider 4c, the holding member 5, or the stage 6. In an eddy current flaw detection test using the inspection device 1, the control unit 23 controls the movement of the probe 10 so as to scan the part surface 41 along the scanning path P (see Figure 5). The scanning path P is a path that crosses the edges 45 of the part surface 41.

[0036] The controller 20 may include a determination unit 21. The determination unit 21 determines a first region signal that indicates the change in eddy currents in the first region 47. In the edge inspection process described later, a first signal and a second signal, described later, which are associated with the same part of the first region 47, may be obtained. In such cases, the determination unit 21 may determine the first region signal from among the first signal and the second signal. Alternatively, the determination unit 21 may determine the signal with the higher intensity from among the first signal and the second signal as the first region signal.

[0037] A display unit 26 may be connected to the controller 20. The display unit 26 is, for example, a liquid crystal display or a touch panel display. The display unit 26 illustrated in Figure 3 displays information related to the signal obtained by the eddy current testing output by the controller 20. The information displayed on the display unit 26 is not particularly limited and may display measurement conditions when performing the eddy current testing, information about the component 40, or other arbitrary information.

[0038] Next, an example of the operation of the inspection device 1 will be described with reference to Figures 5 to 8. In the eddy current testing illustrated in Figure 5, the probe 10 scans the part surface 41 along the scanning path P to detect a signal indicating a change in eddy currents, and an inspection is performed to determine whether or not a defect exists on the part surface 41. In the following explanation, the inspection process using the inspection device 1 will be described using the case where eddy current testing is performed on the outer circumferential surface 42a of the part surface 41 as an example. In addition, the edge inspection process described later will be performed in this inspection process. Note that the part surface 41 on which eddy current testing is performed is not limited to the outer circumferential surface 42a; eddy current testing may be performed on other surfaces of the part surface 41.

[0039] [Inspection Process] In the inspection process, the control unit 23 controls the position or orientation of the probe 10 while performing eddy current testing on the outer surface 42a. That is, in the inspection process, the control unit 23 controls the movement of the probe 10 so that it scans the outer surface 42a along the scanning path P. The probe 10 then detects changes in eddy currents on the outer surface 42a. The outer surface 42a illustrated in Figure 5 has an edge 45, an edge region 46, and a first region 47.

[0040] Edge 45 is the edge that constitutes both ends of the outer peripheral surface 42a in the scanning direction of the probe 10. Edge 45 may include edge 45a which constitutes the end on the positive Z-axis side of the outer peripheral surface 42a and edge 45b which constitutes the end on the negative Z-axis side.

[0041] The edge region 46 is the region of the outer circumferential surface 42a that extends along the edge 45. The edge region 46 may include edge region 46a and edge region 46b. Edge region 46a extends along edge 45a on the negative Z-axis side of edge 45a for a predetermined range. Edge region 46b extends along edge 45b on the positive Z-axis side of edge 45b for a predetermined range. The dimensions of edge regions 46a and 46b in the Z-axis direction are, for example, 1 mm to 5 mm.

[0042] The first region 47 is the region of the outer surface 42a that is directly adjacent to the edge region 46. The first region 47 illustrated in the figure extends between the edge region 46a and the edge region 46b.

[0043] A region 50 is formed outside the edge 45 in the Z-axis direction. Region 50 may include a region 50a located on the positive Z-axis side of edge 45a and a region 50b located on the negative Z-axis side of edge 45b. Region 50a is a space located above the outer circumferential surface 42a and is located outside the edge 45a in the Z-axis direction. Region 50b is a space located below the outer circumferential surface 42a and is located outside the edge 45b in the Z-axis direction.

[0044] The scanning path P illustrated in Figure 5 is the path set when scanning the outer surface 42a. The probe 10 scans the outer surface 42a along the scanning path P. The scanning path P may include multiple paths. For example, the scanning path P includes path P1 and path P2.

[0045] Each of the paths P1 and P2 is a scanning path set on the outer surface 42a. These paths extend, for example, in the Z-axis direction. The overall scanning direction of the probe 10 may be in the negative Z-axis direction for path P1 and in the positive Z-axis direction for path P2. The scanning direction is the direction in which the probe 10 moves when performing a scan.

[0046] Furthermore, as shown in the edge inspection process described later, the probe 10 may be moved in the opposite direction to the overall scanning direction when scanning along paths P1 and P2. For example, when scanning the outer circumferential surface 42a along path P1, the probe 10 may be moved in the positive Z-axis direction while scanning a portion of the outer circumferential surface 42a. Also, the extension direction of the scanning path P is not limited to the illustrated example, and may be set appropriately depending on the shape, dimensions, or position on the part 40 of the surface to be subjected to eddy current testing. For example, paths P1 and P2 may extend in directions that intersect with the Z-axis direction.

[0047] Path P1 is a path from region 50a to region 50b. When scanning along path P1, probe 10 scans region 50a, edge region 46a, first region 47, edge region 46b, and region 50b in that order. Path P2 is a path from region 50b to region 50a. When scanning along path P2, probe 10 scans region 50b, edge region 46b, first region 47, edge region 46a, and region 50a in that order. In this way, each of paths P1 and P2 extends across the edge 45. That is, scanning path P is a path that crosses the edge 45 of the part surface 41. Note that paths P1 and P2 may be set to be separated by a predetermined distance in a direction perpendicular to the Z-axis direction.

[0048] Note that the scanning direction is not limited to the illustrated example; for example, the scanning direction in paths P1 and P2 may be opposite to that in the example shown in Figure 5. Also, the scanning direction in path P1 and the scanning direction in path P2 may be the same.

[0049] {Edge inspection process} Next, the edge inspection process will be explained with reference to Figures 5 to 8. The edge inspection process checks for defects in the area near the edge of the part surface 41. The edge inspection process will be explained below using the case where the probe 10 scans along path P1 as an example.

[0050] In the example shown in Figure 5, when performing eddy current testing on the outer surface 42a along path P1, the control unit 23 moves the probe 10 located in region 50a in the negative Z-axis direction. During this time, the probe 10 detects changes in eddy currents. Here, when crossing edge 45a, the probe 10 scans near point 51. Point 51 is the intersection of edge 45a and path P1. When scanning near point 51, an edge signal, which is a signal caused by the edge effect, is detected. The edge effect refers to the phenomenon in eddy current testing where, when scanning near the edge of part 40, the flow path of eddy currents on the surface of part 40 changes due to the presence of the edge, and a relatively strong signal indicating this change is detected.

[0051] In the edge inspection process, defect signals in the edge region 46 are detected by the probe 10 scanning the edge region 46 along the first scanning path P1a (see Figure 7). The first scanning path P1a is a path that scans in a first direction from the first region 47, across the edge region 46, toward region 50. That is, the scanning path P includes the first scanning path P1a. In the example shown in Figure 7, the positive Z-axis direction corresponds to the first direction. The scanning path P may also include a second scanning path P1b (see Figure 8), which will be described later.

[0052] Referring to Figures 6 to 8, the edge inspection process will be further explained using the case of scanning the edge region 46a as an example. The edge inspection process may include a first step, a second step, and a third step.

[0053] In the first step illustrated in Figure 6, the probe 10, positioned at position 52a in region 50a, scans to an arbitrary position 52b in the first region 47 while moving in the negative Z-axis direction, as indicated by arrow A in the figure. At this time, the probe 10 scans the edge region 46a by crossing the edge 45a in the negative Z-axis direction. In this case, the edge signal is detected from the region on the positive Z-axis side of point 51 to the region on the negative Z-axis side of point 51. Therefore, the signal indicating the change in eddy current detected in the edge region 46a is affected by the edge signal. As a result, for example, even if a defect exists in the edge region 46a, there is a possibility that the defect signal, which is a signal caused by that defect, may be hidden by the edge signal. Thus, in the first step, there is a possibility that it will be difficult to detect defects in the edge region 46a due to the effect of the edge effect. For this reason, the controller 20 may exclude the data related to the signal acquired in the first step from the data related to the signal indicating the change in eddy current on the outer surface 42a.

[0054] Following the first step, the second step is performed. In the second step, the probe 10 scans along the first scanning path P1a. In the second step illustrated in Figure 7, the probe 10 moves in the positive Z-axis direction from position 52b to position 52a, detecting changes in eddy currents. At this time, the probe 10 may scan at least a part of the first region 47 in the positive Z-axis direction while moving from position 52b to position 52c. That is, the probe 10 may detect a first region signal indicating changes in eddy currents in the first region 47. Position 52c may be, for example, the position of the probe 10 when scanning the area around the boundary between the edge region 46a and the first region 47.

[0055] Next, the probe 10 detects changes in eddy currents while moving in the positive Z-axis direction from position 52c to position 52a. That is, it scans in the positive Z-axis direction from edge region 46a to region 50a and detects changes in eddy currents in edge region 46a. At this time, the probe 10 scans along the first scanning path P1a, traversing from edge region 46a to edge 45a. In such cases, the edge signal is mainly detected in the region on the positive Z-axis side of point 51. That is, the signal indicating the change in eddy currents detected when scanning edge region 46a can be suppressed from being affected by the edge signal. Therefore, for example, even if a defect exists in edge region 46a, the defect signal caused by the defect can be suppressed from being hidden by the edge signal, and the defect signal can be detected more reliably. Thus, in the second step, the probe 10 scans along the first scanning path P1a and detects changes in eddy currents in edge region 46a. Therefore, the inspection device 1 can more reliably detect defects present in edge region 46a.

[0056] Following the second step, the third step is performed. In the third step, the probe 10 scans along the second scanning path P1b. The second scanning path P1b is a path that scans in a second direction from the region 50 outside the edge 45, across the edge 45, toward the first region 47. In the example shown in Figure 8, the negative Z-axis direction corresponds to the second direction.

[0057] In the third step illustrated in Figure 8, the probe 10 detects changes in eddy currents as it moves from position 52a in the negative Z-axis direction. At this time, the probe 10 scans the edge region 46a by crossing the edge 45a in the negative Z-axis direction. Therefore, the controller 20 may exclude data related to the signal detected by the probe 10 when it moved from position 52a to position 52c from the data related to the signal indicating changes in eddy currents on the outer surface 42a.

[0058] After scanning from position 52a to position 52c, the probe 10 may scan the first region 47 while moving in the negative Z-axis direction from position 52c to position 52b. That is, the probe 10 may scan along the second scanning path P1b and detect a first region signal indicating a change in eddy currents in the first region 47.

[0059] By performing these first to third steps, if a defect exists in the edge region 46a, the defect signal caused by that defect can be detected more reliably. Note that the edge inspection process is not limited to the examples shown in Figures 6 to 8. For example, if the scanning by the probe 10 starts from position 52b, the second and third steps may be performed without performing the first step.

[0060] In eddy current testing along path P1, after the third step, the probe 10 may be moved from the first region 47 across the edge region 46b to the region 50b (see Figure 5) outside the edge 45b while scanning the outer surface 42a. In this case, the probe 10 scans in the negative Z-axis direction from the edge region 46b to region 50b. Therefore, the signal detected in the edge region 46b can be suppressed from being affected by the edge signal originating from the edge 45b. Consequently, even if a defect exists in the edge region 46b, for example, the defect signal originating from that defect can be detected more reliably. Note that when scanning the edge region 46b in eddy current testing along path P1, the negative Z-axis direction corresponds to the first direction.

[0061] Thus, the inspection process using the inspection device 1 includes an edge inspection process in which the edge regions 46a and 46b are scanned along the first scanning path P1a, making it possible to more reliably detect changes in eddy currents in the edge regions 46a and 46b.

[0062] Furthermore, in the examples shown in Figures 6 to 8, the first region signal may be detected by scanning the first region 47 in the positive Z-axis direction (see Figure 7) and scanning the first region 47 in the negative Z-axis direction (see Figure 8). That is, the first region signal may include a first signal detected by scanning along the first scanning path P1a and a second signal detected by scanning along the second scanning path P1b. In that case, there will be duplicate data for the first region signal associated with the same part of the first region 47. Therefore, the determination unit 21 may determine the first region signal corresponding to the region from among the first signal and the second signal. Alternatively, the determination unit 21 may determine the signal with the higher intensity from among the first signal and the second signal as the first region signal. Note that in the inspection device 1, the intensity of the signal indicating the change in eddy current may be detected as a positive or negative voltage (V). For example, the determination unit 21 may determine the signal with the larger absolute value of voltage from among the first signal and the second signal as the first region signal.

[0063] In the inspection process illustrated in Figure 5, eddy current testing is performed on the outer surface 42a along path P1, and then eddy current testing is performed on the outer surface 42a along path P2. In this case, scanning along path P2 may be performed using the same process as when performing eddy current testing along path P1.

[0064] In the path P2 illustrated in Figure 5, the probe 10 positioned in region 50b scans the outer surface 42a while moving as a whole in the positive Z-axis direction. Therefore, changes in eddy currents in the edge region 46b may be detected by the probe 10 scanning from the first region 47, across the edge region 46b, and toward region 50b. In this case, the negative Z-axis direction corresponds to the first direction. Alternatively, changes in eddy currents in the first region 47 may be detected by the probe 10 scanning from region 50b, across the edge 45b, and toward the first region 47. In this case, the positive Z-axis direction corresponds to the second direction.

[0065] Note that the scanning path P is not limited to paths P1 and P2 shown in Figure 5. That is, the scanning path P may be set appropriately according to the shape or dimensions of the surface to be subjected to eddy current testing. In addition to paths P1 and P2, the scanning path P may also include further scanning paths. For example, after scanning along paths P1 and P2, the probe 10 may be moved to the side and the outer circumferential surface 42a may be scanned in the same manner as scanning along path P1. Alternatively, after scanning the outer circumferential surface 42a, eddy current testing may be performed on the side surface 43a.

[0066] Next, the effects and advantages of the eddy current testing apparatus and eddy current testing method according to the embodiment will be described.

[0067] (1) The eddy current flaw detection apparatus 1 according to this embodiment includes a probe 10 that detects changes in eddy currents on the surface 41 of a part to be inspected 40, and a control unit 23 that causes the probe 10 to scan the part surface 41 along a scanning path P that crosses the edge 45 of the part surface 41. The scanning path P includes a first scanning path P1a that scans in a first direction from a first region 47 adjacent to an edge region 46 extending along the edge 45 of the part surface 41, across the edge region 46, toward a region 50 outside the edge 45. The probe 10 scans along the first scanning path P1a and detects changes in eddy currents in the edge region 46.

[0068] In the inspection device 1 according to this embodiment, when detecting changes in eddy currents in the edge region 46, the device scans from the edge region 46 across the edge 45 toward the region 50. Therefore, the signal indicating the change in eddy currents detected when scanning the edge region 46 can be suppressed from being affected by the edge effect. As a result, even if a defect exists in the edge region 46, for example, the defect signal is suppressed from being hidden by the edge signal, and the defect signal can be detected more reliably. Thus, the inspection device 1 can more reliably detect defects present in the edge region 46. In other words, eddy current testing can be performed more easily with the inspection device 1.

[0069] (2) The scanning path P includes a second scanning path P1b that scans in a second direction from a region 50 outside the edge 45, across the edge 45, toward the first region 47, and the probe 10 may scan along the second scanning path P1b to detect changes in eddy currents in the first region 47.

[0070] This allows, for example, scanning of the edge region 46 along the first scanning path P1a, followed by scanning of the first region 47 along the second scanning path P1b. Therefore, scanning of both the edge region 46 and the first region 47 can be performed along the scanning path P. Thus, eddy current testing can be performed more easily.

[0071] (3) The eddy current flaw detection apparatus 1 may include a determination unit 21 that determines a first region signal indicating a change in eddy currents in the first region 47. The first region signal may include a first signal detected by scanning along a first scanning path P1a and a second signal detected by scanning along a second scanning path P1b. The determination unit 21 may determine the first region signal to be the one with the higher intensity of the first signal and the second signal.

[0072] As a result, even if data related to the first region signal is obtained redundantly through scanning along the first scanning path P1a and scanning along the second scanning path P1b, the signal with the higher intensity can be determined as the first region signal. Therefore, defect signals in the first region 47 can be detected more reliably.

[0073] (4) In the eddy current testing method according to the embodiment, the part surface 41 of the object to be inspected 40 is scanned with a probe 10 that detects changes in eddy currents on the part surface 41 along a scanning path P that crosses the edge 45 of the part surface 41. In this method, the scanning path P includes a first scanning path P1a that scans in a first direction from a first region 47 adjacent to an edge region 46 extending along the edge 45 of the part surface 41, across the edge region 46, toward a region 50 outside the edge 45. In this method, the probe 10 scans along the first scanning path P1a and detects changes in eddy currents in the edge region 46.

[0074] In the eddy current testing method according to this embodiment, when detecting changes in eddy currents in the edge region 46, the scanner is performed from the edge region 46 across the edge 45 towards the region 50. Therefore, the signal indicating changes in eddy currents detected when scanning the edge region 46 can be suppressed from being affected by the edge effect. As a result, even if a defect exists in the edge region 46, for example, the defect signal will not be obscured by the edge signal, and the defect signal can be detected more reliably. Thus, defects present in the edge region 46 can be detected more reliably. In other words, eddy current testing can be performed more easily.

[0075] This disclosure can contribute, for example, to Sustainable Development Goal (SDG) 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation."

[0076] Although several embodiments have been described above, it is possible to modify or transform the embodiments based on the above disclosure. All components of the above embodiments and all features described in the claims may be individually selected and combined, provided that they do not contradict each other.

Claims

1. The system includes an excitation coil that generates eddy currents on the surface of a component to be inspected, and a detection coil that detects the magnetic field induced by the eddy currents, and a probe that detects changes in the eddy currents. A control unit that causes the probe to scan the surface of the part along a scanning path that crosses the edge of the surface of the part, The decision part, Equipped with, The scanning path includes a first scanning path that scans in a first direction from a first region adjacent to an edge region extending along the edge on the surface of the part, across the edge region, toward a region outside the edge, and a second scanning path that scans in a second direction from the region outside the edge, across the edge, toward the first region. The probe scans across the edge along the first scanning path and detects the change in the eddy current in the edge region, and further scans across the edge along the second scanning path and detects the change in the eddy current in the first region. The determination unit determines a first region signal that indicates the change in the eddy current in the first region, The first region signal includes a first signal detected by scanning along the first scanning path and a second signal detected by scanning along the second scanning path. The determination unit determines the signal with the higher intensity of the first signal and the second signal as the first region signal, in an eddy current flaw detection apparatus.

2. The probe includes an excitation coil that generates eddy currents on the surface of the part to be inspected, and a detection coil that detects the magnetic field induced by the eddy currents, and scans the surface of the part along a scanning path that crosses the edge of the part surface, The scanning path includes a first scanning path that scans in a first direction from a first region adjacent to an edge region extending along the edge on the surface of the part, across the edge region, toward a region outside the edge, and a second scanning path that scans in a second direction from the region outside the edge, across the edge, toward the first region. The probe is used to scan across the edge along the first scanning path and detect changes in the eddy currents in the edge region, and to scan across the edge along the second scanning path and detect changes in the eddy currents in the first region. A first region signal indicating the change in the eddy current in the first region is determined, The first region signal includes a first signal detected by scanning along the first scanning path and a second signal detected by scanning along the second scanning path. Of the first signal and the second signal, the one with the higher intensity is determined to be the first region signal. Eddy current testing method.

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