JP2016205902A - Eddy current flaw detection device and eddy current flaw detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eddy current flaw detection device and an eddy current flaw detection method which are capable of sufficiently reducing striped noise in an image obtained as a flaw detection result.SOLUTION: An eddy current flaw detection device 1 comprises: input means A2 for inputting axial direction information; flaw detection means A1 for sequentially measuring an electromotive force in each measurement position while switching a channel; division means A3 for dividing measured electromotive forces into a plurality of data groups each of which corresponds to the same axial direction; arithmetic processing means A4 for performing arithmetic processing on the divided data groups independently from one another by using operators for correcting sensitivity depending on their respective axial directions; rearraying means A5 for rearraying results of the arithmetic processing on the data groups so that they correspond to their respective measured positions; and display means A6 for displaying the results of the arithmetic processing in association with their respective measurement positions.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an eddy current flaw detector and an eddy current flaw detection method.

  Eddy current flaw detectors are widely used for defect inspection of structures formed of conductive materials. This eddy current flaw detection apparatus detects an eddy current in a structure to be inspected using an exciting coil and detects a change in the eddy current in the vicinity of the defect by a detection coil.

  As such an eddy current flaw detector, for example, a multi-coil probe that scans a plurality of coils arranged in two rows in a staggered pattern is used, and a set of excitation coil and detection coil among the plurality of coils is used. Are assigned to form a set of channels, and the channels are sequentially switched so that a wide range is flaw-detected (see, for example, Non-Patent Document 1).

  In the above apparatus, an X scan that scans coils arranged in a direction perpendicular to the scanning direction of the probe as an excitation coil and a detection coil, and coils that are arranged obliquely in the horizontal direction with respect to the scanning direction are detected as an excitation coil. Flaw detection is performed in combination with a Y-scan that scans as a coil. Such a combination (channel) of the excitation coil and the detection coil has high detection sensitivity with respect to the axial direction of the channel axis passing through the central portion of the excitation coil and the central portion of the detection coil. By combining the scans, it is possible to detect defects in the measurement region with a single scan even for defects whose position and orientation are indefinite.

Ryo Nishimizu and 10 others, “Development of an eddy current flaw detection system for inspecting complex shapes”, Japanese Atomic Energy Society of Japan, 2008, Vol. 7, no. 2, p. 142-151

  However, when the conventional eddy current flaw detector as described above is used, for example, as shown in FIG. 12, in the image obtained as a flaw detection result, striped noise may occur between adjacent channels. This is due to the sensitivity characteristics of eddy current detection that depends on the direction of the channel axis. Even when measuring the same defect, the sensitivity characteristics differ between adjacent channels with different axial directions. This is considered to be because striped noise is generated as a result.

  The present invention has been made based on the above circumstances, and an object of the present invention is to provide an eddy current flaw detection apparatus and an eddy current flaw detection method capable of sufficiently reducing stripe noise in an image obtained as a result of flaw detection. It is to provide.

The present invention
(1) An axis of a channel axis having a plurality of channels obtained by combining a pair of excitation coils and detection coils, and passing through the central portion of the excitation coil and the central portion of the detection coil in at least a part of the channels An eddy current flaw detector comprising a multi-coil probe whose direction intersects obliquely with respect to a scanning direction and at least two or more intersecting angles between the axial direction and the scanning direction are set,
Input means for inputting information in the axial direction corresponding to each channel;
Flaw detection means for sequentially measuring the electromotive force at each measurement position while switching the channel;
A dividing means for dividing the measured value of the electromotive force measured by the flaw detection means into a plurality of data groups having the same axial direction;
Arithmetic processing means for independently processing each data group divided by the dividing means using an operator for correcting sensitivity in the axial direction;
Rearrangement means for rearranging the calculation results of the data groups calculated by the calculation processing means so as to correspond to the measurement positions;
An eddy current flaw detector comprising: display means for displaying the calculation result rearranged by the rearrangement means in association with the measurement position;
(2) In the above (1), the input of axial information in the input means is performed by designating individual channels or by collectively performing a plurality of channels based on regularity. The eddy current flaw detector as described,
(3) The eddy current flaw detector according to (1) or (2), wherein the channel switching in the flaw detector is performed by a multiplexer.
(4) The eddy current flaw detector according to any one of (1) to (3), wherein the arithmetic processing in the arithmetic processing means is processing by a digital filter.
(5) The eddy current flaw detector according to any one of (1) to (4), wherein the array rearranged by the rearrangement means is a two-dimensional array.
(6) The eddy current flaw detector according to any one of (1) to (5), wherein the display of the calculation result in the display means is a color tone display or a gradation display corresponding to the calculation result,
(7) An axis of a channel axis having a plurality of channels in which a pair of excitation coils and detection coils are combined, and passing through the central portion of the excitation coil and the central portion of the detection coil in at least a part of the channels An eddy current flaw detector comprising a multi-coil probe whose direction intersects obliquely with respect to a scanning direction and at least two or more intersecting angles between the axial direction and the scanning direction are set,
Flaw detection means for sequentially measuring the electromotive force at each measurement position while switching the channel;
Arithmetic processing means for collectively calculating the measured value of the electromotive force measured by the flaw detection means using an operator for correcting sensitivity in the axial direction;
An eddy current flaw detector comprising: display means for displaying a calculation result calculated by the calculation processing means in association with the measurement position and displaying a color tone or gradation corresponding to the calculation result. ,
(8) A channel axis that has a plurality of channels in which a pair of excitation coils and detection coils are combined, and passes through the central portion of the excitation coil and the central portion of the detection coil in at least a part of the channels. An eddy current flaw detection method using a eddy current flaw detector provided with a multi-coil probe whose direction intersects obliquely with respect to the scanning direction and at least two crossing angles between the axial direction and the scanning direction are set. Because
Inputting the axial information corresponding to each channel;
Sequentially measuring the electromotive force at each measurement position while switching the channel by scanning on the subject using the multi-coil probe;
Dividing the measurement value of the electromotive force into a plurality of data groups having the same axial direction;
A step of independently performing arithmetic processing on the divided data group using an operator for correcting sensitivity in the axial direction;
Rearranging the computation results of the data groups that have undergone the computation processing so as to correspond to the measurement positions;
And a step of displaying the rearranged calculation results in association with the measurement positions, and (9) a plurality of channels in which a pair of excitation coils and detection coils are combined. In at least a part of the channels, the axial direction of the channel axis passing through the central portion of the exciting coil and the central portion of the detecting coil crosses obliquely with respect to the scanning direction, and the axial direction and the scanning An eddy current flaw detection method for flaw detection using an eddy current flaw detector provided with a multi-coil probe in which at least two crossing angles with a direction are set,
Sequentially measuring the electromotive force at each measurement position while switching the channel by scanning on the subject using the multi-coil probe;
A step of collectively calculating the measured value of the electromotive force using an operator for correcting the sensitivity in the axial direction;
And a step of displaying the calculated calculation result in association with the measurement position in correspondence with the calculation result.

  In this specification, “excitation coil” means a coil for generating high frequency for generating eddy current in a subject, and “detection coil” measures eddy current generated by the excitation coil. Means a coil for. Further, in this specification, “channel” means a measurement range including a combination of a pair of excitation coils and a detection coil, and “channel axis” means a central portion of the excitation coil and a central portion of the detection coil. Means the axis of the channel through

  The present invention can provide an eddy current flaw detector and an eddy current flaw detection method that can sufficiently reduce stripe noise in an image obtained as a result of flaw detection.

It is a schematic block diagram which shows 1st Embodiment of the eddy current flaw detector of this invention. It is a schematic plan view for demonstrating the X scan in the multi-coil probe of the eddy current flaw detector of FIG. 1, Comprising: (a) is a general view, (b) shows the one part enlarged view of (a), respectively. It is a schematic plan view for demonstrating Y scan in the multi-coil probe of the eddy current flaw detector of FIG. 1, Comprising: (a) is a general view, (b) shows the one part enlarged view of (a), respectively. It is a schematic perspective view of the flaw detection means in the eddy current flaw detection apparatus of FIG. It is the schematic which expands and shows a part of multi coil probe of FIG. It is a schematic block diagram for demonstrating operation | movement of the eddy current flaw detector of FIG. It is a figure which shows an example of the electromotive force measurement value array stored in the flaw detection data recording part of FIG. FIG. 8 is an example of an array of data groups obtained by dividing the electromotive force measurement value array of FIG. 7, where (a) is an array of odd-numbered channel data groups, and (b) is an array of even-numbered channel data groups. Each is shown. It is a two-dimensional image which shows an example of the defect measured using the eddy current flaw detector of FIG. It is a schematic block diagram which shows 2nd Embodiment of the eddy current flaw detector of this invention. It is a schematic block diagram for demonstrating operation | movement of the eddy current flaw detector of FIG. It is a two-dimensional image which shows an example of the defect measured using the conventional eddy current flaw detector.

<Eddy current flaw detector>
The eddy current flaw detector of the present invention has a plurality of channels in which a pair of excitation coils and detection coils are combined, and at least a part of the channels includes a central portion of the excitation coils and a central portion of the detection coils. An eddy current flaw detector comprising a multi-coil probe in which the axial direction of the channel axis passing through the crossing is obliquely intersecting the scanning direction and at least two or more intersecting angles between the axial direction and the scanning direction are set. , Input means for inputting information in the axial direction corresponding to each channel, flaw detection means for sequentially measuring the electromotive force at each measurement position while switching the channel, and measurement of the electromotive force measured by the flaw detection means Dividing means for dividing the value into a plurality of data groups having the same axial direction, and for each data group divided by the dividing means, An arithmetic processing unit that performs arithmetic processing independently using an operator for correcting sensitivity according to direction, and an arithmetic result of each data group that has been arithmetically processed by the arithmetic processing unit is regenerated so as to correspond to the measurement position. It is characterized by comprising rearranging means for arranging and display means for displaying the calculation results rearranged by the rearranging means in association with the measurement positions.

  As described above, the eddy current flaw detector according to the present invention includes the dividing unit, the arithmetic processing unit, and the rearrangement unit. Therefore, it is possible to sufficiently reduce the stripe noise in the image obtained as a result of the flaw detection. As a result, defects such as scratches can be reliably detected.

  In addition, the present invention has a plurality of channels in which a pair of excitation coils and detection coils are combined, and at least a part of the channels passes through the central portion of the excitation coil and the central portion of the detection coil. An eddy current flaw detector comprising a multi-coil probe in which an axial direction of an axis obliquely intersects a scanning direction and at least two or more intersecting angles between the axial direction and the scanning direction are set. Flaw detection means for sequentially measuring the electromotive force at each measurement position while switching, and the measured value of the electromotive force measured by the flaw detection means are collectively collected using an operator for correcting the sensitivity in the axial direction. An arithmetic processing means for performing arithmetic processing and an arithmetic result processed by the arithmetic processing means are associated with the measurement position and color corresponding to the arithmetic result. Including an eddy current flaw detection apparatus characterized by comprising display means for displaying or gradation display.

  As described above, since the eddy current flaw detection apparatus of the present invention includes the above arithmetic processing means, it is possible to sufficiently reduce the stripe noise in the image obtained as a flaw detection result. Defects can be detected reliably.

  Hereinafter, although the 1st and 2nd embodiment of the said eddy current flaw detector is described with reference to FIGS. 1-11, this invention is not limited only to embodiment described in the said drawing.

[First Embodiment]
FIG. 1 is a schematic block diagram showing a first embodiment of an eddy current flaw detector according to the present invention. As shown in FIG. 1, the eddy current flaw detection apparatus 1 schematically includes flaw detection means A1, input means A2, division means A3, arithmetic processing means A4, rearrangement means A5, and display means A6. It is comprised by.

  The flaw detection means A1 is means for sequentially measuring the electromotive force at each measurement position while switching channels. As shown in FIG. 1, the flaw detection means A1 includes a multi-coil probe 110, a multiplexer 120, a multi-flaw detector 130, and a movement control mechanism 140.

  The multi-coil probe 110 has a plurality of channels in which a pair of excitation coils and detection coils are combined, and at least a part of the channels passes through the central portion of the excitation coil and the central portion of the detection coil. The axial direction of the axis crosses obliquely with respect to the scanning direction, and at least two or more intersection angles between the axial direction and the scanning direction are set. Specifically, in the first embodiment, as shown in FIGS. 2 (a) and 3 (a), 51 coils in two rows of rows A and B on a flexible substrate 111 are provided. 112 (A row: 26 pieces, B row: 25 pieces) are arranged in a staggered pattern. Here, the pair of excitation coils and detection coils are appropriately selected from a plurality of coils using a multiplexer 120 described later. For example, as shown in FIG. 2B and FIG. An excitation coil E and a detection coil D can be selected. Further, the crossing angle in the axial direction of the channel axis obliquely intersecting the scanning direction is two settings, + γ and −γ, as shown in FIG.

  As described above, by arranging the coils 112 in a staggered manner, the axial directions of adjacent channel axes can be arranged in two oblique directions with respect to the scanning direction, and the detection ability changes with respect to the direction of the scratch. Can be suppressed.

  The multiplexer 120 performs channel switching in the flaw detection means A1. Specifically, the multiplexer 120 selects two coils 112 from the plurality of coils 112, and functions one of the selected two coils as an excitation coil E and the other as a detection coil D. A measurement range (channel, also referred to as “ch” in the drawing) composed of a combination of the pair of excitation coil E and detection coil D, and a channel number 1 (1 ch) etc. with a number assigned to distinguish each channel. Are sequentially switched electronically. By using the multiplexer 120 in this way, the excitation coil E and the detection coil D can be easily assigned and the channel can be easily switched.

  Here, the mode in which the combination of the pair of excitation coil E and detection coil D is selected from the coils 112 arranged in the direction orthogonal to the scanning direction of the multi-coil probe 110 is the first mode. A mode in which the combination of the pair of excitation coil E and detection coil D is selected from the coils 112 arranged in the diagonally horizontal direction with respect to the scanning direction is referred to as a second mode.

  As shown in FIG. 2A, the first mode is, for example, the first coil 112 in row A (the coil at the upper end of the page is the first coil, and the second coil, Channel 1 (1ch) in which the coil, etc., the same applies hereinafter) is selected as the excitation coil E, the third coil in the A row is the detection coil D, the second coil in the A row is the excitation coil E, and the fourth coil in the A row is The channel 2 (2ch) selected as the detection coil D and the channels 3 (3ch) to 24 (24ch) selected in the same manner are configured.

  On the other hand, in the second mode, as shown in FIG. 3A, for example, the channel 25 (25ch) in which the second coil in the A row is selected as the excitation coil E and the second coil in the B row is selected as the detection coil D. The channel 26 (26ch) selected with the third coil in the A row as the exciting coil E and the second coil in the B row as the detection coil D, and the channels 27 (27ch) to 72 (72ch) selected in the same manner. It is comprised by.

  The first mode channel 1 (1ch) to channel 24 (24ch) are mainly for defect detection in the direction orthogonal to the scanning direction of the multi-coil probe 110, and the second mode channels 25 (25ch) to The channel 72 (72ch) mainly targets defect detection in the same direction as the scanning direction of the multi-coil probe 110.

  Therefore, the multi-coil probe 110 is scanned once along the surface of the subject s (various surfaces such as a flat surface and a curved surface) (scanning in the directions indicated by arrows in FIGS. 2A and 3A). Thus, the flaws oriented in all directions can be detected by the channels 1 to 72 of the multi-coil probe 110.

  The multi-flaw detector 130 inputs an electromotive force measurement value measured by a detection coil of a selected channel, acquires a flaw detection signal from the electromotive force measurement value, and digitally transmits the signal through an A / D converter. Output as a signal. Similar to a general eddy current flaw detector, the multi-flaw detector 130 compares the measured value of the electromotive force with a predetermined reference voltage, and outputs a signal having the same phase component as the reference voltage from the measured value. And a function of extracting a signal having a different phase component whose phase is delayed by 90 degrees. These in-phase component signals and out-of-phase component signals are output to a personal computer 150, which will be described later, at regular intervals by sequentially switching channels using the multiplexer 120.

  The movement control mechanism 140 is a mechanism that scans the multi-coil probe 110. As shown in FIG. 4, the movement control mechanism 140 is roughly configured by a rotary stage 141, a traveling arm 142, and a traveling rail 143.

  The rotary stage 141 holds the multi-coil probe 110 via an elastic body 146 such as a sponge and adjusts the angle of the multi-coil probe 110 with respect to the scanning direction (shown by an arrow in FIG. 4). Normally, the multi-coil probe 110 is adjusted by the rotary stage 141 so that the arrangement direction (longitudinal direction) of the coils 112 is orthogonal to the scanning direction.

  The scanning arm 142 holds the rotary stage 141 and scans the multi-coil probe 110 along the scanning direction. The scanning arm 142 is a jig assembled in an L shape by connecting linear stages that can expand and contract, and can move the multi-coil probe 110 in the vertical direction and the horizontal direction. By operating the scanning arm 142, the multi-coil probe 110 can be adjusted to the measurement position of the subject s.

  An encoder 144 that outputs horizontal position information of the multi-coil probe 110 is attached to the scanning arm 142. The horizontal position information from the encoder 144, the angle information of the rotary stage 141, and the multi-coil probe. By obtaining information on the measurement position on the subject s using the 110 channel information, the information on the measurement position can be associated with the measured value of the electromotive force. Instead of the information from the encoder 144, horizontal position information calculated from the relationship between the scanning speed and the scanning time may be used, or the scanning time based on the scanning speed may be used instead of the horizontal position information. .

  The scanning rail 143 supports the scanning arm 142 slidably. The scanning rail 143 is fixed on a base 145 on which the subject s is placed. By moving the scanning arm 142 back and forth on the scanning rail 143, the measurement position on the subject s can be adjusted.

  The input means A2 is a means for inputting information in the axial direction corresponding to each channel. According to this input means A2, an operator for correcting sensitivity in the axial direction can also be input. As the input device 160 that constitutes the input means A2, for example, a mouse, a keyboard, or the like can be employed.

  Here, the axial direction of the channel axis input by the input means A2 will be described in detail. The axial direction is roughly classified into an axial direction according to the first mode and an axial direction according to the second mode. Among these modes, in order to reduce striped noise, it is important to specify the axial direction according to the second mode that switches alternately according to the channel order. This is because the sensitivity characteristics of eddy current detection differ depending on the angle of the channel axis in the axial direction.

  Specifically, as shown in FIG. 5, a measurement range consisting of a combination of a pair of excitation coils 1121 and a detection coil 1122 is a channel 25, and a measurement range consisting of a combination of a pair of excitation coils 1123 and a detection coil 1122 is a channel. 26, the axial direction of the channel 25 has an angle −γ with respect to the scanning direction, and the axial direction of the channel 26 has an angle + γ with respect to the scanning direction. Similarly, the axial direction of the odd-numbered channel has an angle −γ with respect to the scanning direction, and the axial direction of the even-numbered channel has an angle + γ with respect to the scanning direction. Therefore, for the purpose of correcting the sensitivity characteristics of eddy current detection that varies depending on the angle in the axial direction, the odd-numbered channel and the even-numbered channel are input so as to be distinguished.

  In addition, it is preferable that the input of the information in the axial direction in the input unit A2 is performed by designating individual channels or performing a plurality of channels collectively based on regularity. Specific examples of applying such a configuration include, for example, input performed by specifying individual channels when there is no regularity in the axial direction of the channel axis, and all axial directions (A direction) of odd-numbered channel axes. When the axis directions of the even-numbered channel axes (the B direction different from the A direction) are all the same direction, the odd-numbered channel axis is based on the regularity of whether it is odd-numbered or even-numbered. The input etc. which perform a channel and an even-numbered channel all together are mentioned. Thereby, the axial information of each channel can be input efficiently.

  The dividing unit A3 divides the electromotive force measurement value measured by the flaw detection unit A1 into a plurality of data groups having the same axial direction. As shown in FIG. 6, the dividing means A3 is roughly constituted by a flaw detection data recording unit 151, a channel recording unit 152, a data division processing unit 153, and a data division recording unit 154.

  The flaw detection data recording unit 151 records the measurement value of the electromotive force measured by the flaw detection means A1 and arranged in accordance with the measurement position. Here, FIG. 7 is a diagram showing an example of an electromotive force measurement value array stored in the flaw detection data recording unit 151 of FIG. The measured value of the electromotive force is associated with the measurement position (the position specified by the channel and the distance scanned in the scanning direction) and is recorded as a numerical matrix.

  The channel recording unit 152 records the channel input by the input device 160 of the input unit A2 described above. The data division processing unit 153 divides the measurement value recorded in the flaw detection data recording unit 151 for each channel designated by the input unit A2. 8 is an example of an array of each data group obtained by dividing the array of measured electromotive force values in FIG. 7. FIG. 8A is an array of data groups of odd-numbered channels, and FIG. ) Shows an array of data groups of even-numbered channels. The data division recording unit 154 records the measurement value of the electromotive force separately for each data group.

  In addition, it is preferable that the measured value of the electromotive force in the data group is arranged corresponding to the measurement position as shown in FIGS. 8 (a) and 8 (b). Thereby, a measurement position and the measured value of an electromotive force can be matched easily and reliably.

  The arithmetic processing means A4 independently performs arithmetic processing on each data group divided by the dividing means A3 using an operator for correcting sensitivity in the axial direction. The arithmetic processing means A4 is roughly composed of an operator recording unit 155, a filter arithmetic unit 156, and an arithmetic data recording unit 157.

  The operator recording unit 155 records the operator input by the input unit A2. The filter calculation unit 156 uses the operator recorded in the operator recording unit 155 to perform calculation processing for correcting the sensitivity in the axial direction for each data group recorded in the data division recording unit 154. The calculation data recording unit 157 records the calculation result processed by the filter calculation unit 156.

  Here, as an operator used in the filter calculation unit 156, for example, a matrix operator as a sharpening filter (a filter that emphasizes the outline of a defect) represented by the following formula (1) can be exemplified. This operator performs a process of replacing the value with the median by taking the product-sum of each data group recorded in the data division recording unit 154 and the operator.

  Note that the arithmetic processing in the arithmetic processing means A4 is preferably processing by a digital filter. In the present invention, for example, a digital filter that functions as the sharpening filter can be used. As described above, since the calculation process is a process using a digital filter, a desired calculation (calculation for emphasizing a defect at each measurement position) can be easily performed, and a defect in the subject s can be reliably detected. Can do.

  The rearrangement means A5 rearranges the calculation results of each data group calculated by the calculation processing means A4 so as to correspond to the measurement positions. The rearrangement means A5 is roughly constituted by a rearrangement processing unit 158 and a rearrangement data recording unit 159.

  The rearrangement processing unit 158 rearranges the calculation results for each data group so as to correspond to the measurement positions. Specifically, for example, when the dividing unit A3 divides into odd-numbered channels and even-numbered channels as described above, the obtained calculation results are rearranged in the order of channels and integrated into one. The mode of rearrangement is not particularly limited, and for example, a two-dimensional array corresponding to a two-dimensional measurement position, a one-dimensional array limited to a specific region of the subject s, or the like can be employed. However, the array rearranged by the rearrangement means A5 is preferably a two-dimensional array. Thereby, a measurement position and the correction value of the measured value of an electromotive force can be matched easily and reliably. The rearrangement data recording unit 159 records the operation result rearranged by the rearrangement processing unit 158.

  The dividing means A3, the arithmetic processing means A4, and the rearranging means A5 are not particularly limited as long as the above-described processing can be performed. However, from the viewpoint of mobility, operability, etc., these means are combined. One processing apparatus is preferable, and from the viewpoint of availability, the personal computer 150 satisfying desired processing performance is more preferable.

  The display unit A6 displays the calculation result rearranged by the rearrangement unit A5 as an image in association with the measurement position. As the display means A6, for example, a monitor 170 such as a two-dimensional display can be employed. The calculation result display in the display means A6 is preferably color tone display or gradation display corresponding to the calculation result, and more preferably color tone display. Thereby, the magnitude | size, shape, etc. of the detected defect can be visually recognized easily and reliably.

Next, a flaw detection method using the eddy current flaw detection apparatus 1 will be described. However, the flaw detection method using the eddy current flaw detection apparatus 1 is not limited to the following modes.
(Step a1) First, information on the axial direction corresponding to each channel and an operator for correcting sensitivity in the axial direction are input. When the operator is input in advance, the input of the operator can be omitted.
(Step a2) Next, the electromotive force at each measurement position is sequentially measured while switching channels by scanning on the subject using the multi-coil probe. Specifically, in the flaw detection means A1, the subject s is placed and fixed on the base 145 of the eddy current flaw detector 1, and the movement control mechanism 140 is operated to measure the multi-coil probe 110 on the subject s. Place it at the start position. After the arrangement of the multi-coil probe 110 is completed, the channel to be measured by the multiplexer 120 is switched, the electromotive force is measured for the channels 1 to 72 using the multi-coil probe 110, and the measured value of the electromotive force is balanced (zero calibration). ) After this measurement is completed, the multi-coil probe 110 is moved in the scanning direction by the movement control mechanism 140 to sequentially measure, and the series of operations is repeated thereafter to measure the entire measurement range.

(Step a3) Next, the measured value of the electromotive force is divided into a plurality of data groups having the same axial direction. Specifically, prior to this division, a flaw detection signal is first acquired from the measured values of electromotive force, and this flaw detection signal is A / D converted. Acquisition of the flaw detection signal from the measurement value of the electromotive force and A / D conversion of the flaw detection signal are performed by the multi-flaw detector 130, and the A / D converted signal is transmitted from the encoder 144 connected to the scanning arm 142. Are transmitted to the dividing means A3 together with the information of the measurement positions. The signal received by the dividing unit A3 is recorded in the flaw detection data recording unit 151, and is divided into a plurality of data groups by the data division processing unit 153 based on the axial information of each channel input by the input unit A2. The divided data group is divided for each data group and recorded in the data division recording unit 154 and transmitted to the arithmetic processing means A4.

(Step a4) Next, the divided data group is independently processed using an operator for correcting the sensitivity in the axial direction. Specifically, using the operator input by the input unit A2, the filter arithmetic unit 156 performs arithmetic processing on the signal (signal divided into data groups) received by the arithmetic processing unit A4. As said operator, the matrix etc. which are represented by said Formula (1) are applicable, for example. The calculation result obtained by the calculation process is recorded in the calculation data recording unit 157 and transmitted to the rearrangement unit A5.
(Step a5) Next, the calculation results of the data groups subjected to the calculation process are rearranged so as to correspond to the measurement positions. Specifically, the signal (calculation result) received by the rearrangement unit A5 is rearranged by the rearrangement processing unit 158, and the rearranged data is recorded in the rearrangement data recording unit 159 and transmitted to the display unit A6. Is done.
(Step a6) Next, the rearranged calculation results are displayed in association with the measurement positions. The display method is not particularly limited. For example, the received calculation result is displayed as a two-dimensional image on the monitor 170 of the display unit A6 in association with the measurement position.

  The images obtained as described above are shown below. First, FIG. 12 is a two-dimensional image showing an example of a defect DF measured using a conventional eddy current flaw detector. This image is obtained by flaw detection on a specimen s of 150 mm × 150 mm × 25 mm to which a fatigue crack is applied. As can be seen from FIG. 12, striped noise is observed between adjacent channels (odd-numbered channel and even-numbered channel). On the other hand, FIG. 9 is a two-dimensional image showing an example of the defect DF measured using the eddy current flaw detector 1 of FIG. The subject s in this image is the same as the one provided with the fatigue crack. As can be seen from FIG. 9, the stripe noise between adjacent channels is reduced compared to that of FIG. 12, and the flaw detection signal related to the crack is detected with a high SN ratio. As described above, since the determination accuracy is improved by improving the SN ratio, a detailed inspection is unnecessary as a result, and the time in the entire inspection process can be shortened.

[Second Embodiment]
FIG. 10 is a schematic block diagram showing a second embodiment of the eddy current flaw detector according to the present invention. As shown in FIG. 10, the eddy current flaw detection apparatus 2 is roughly constituted by flaw detection means A1, input means B2, arithmetic processing means B4, and display means A6. The second embodiment is different particularly in that the dividing unit A3 and the rearrangement unit A5 of the first embodiment are not provided. Since the flaw detection means A1 and the display means A6 have the same configuration as that of the first embodiment, the same parts are denoted by the same reference numerals, and detailed description thereof is omitted.

  The input means B2 is a means for inputting an operator used for correcting the sensitivity in the axial direction. As the input device 260 constituting the input unit B2, for example, a keyboard or the like can be adopted as in the first embodiment. In this embodiment, since the electromotive force measurement value is collectively calculated based on the predetermined axial information of each channel, it is not necessary to input the axial information in the input means B2. .

  The arithmetic processing means B4 collectively calculates the measured electromotive force values measured by the flaw detection means A1 using an operator for correcting the sensitivity in the axial direction. As shown in FIG. 11, the arithmetic processing means B4 is roughly configured by a flaw detection data recording unit 251, an operator recording unit 255, a filter calculation unit 256, and a calculation data recording unit 257.

  The flaw detection data recording unit 251 records the measurement value of the electromotive force measured by the flaw detection means A1 and arranged in accordance with the measurement position. Since this flaw detection data recording unit 251 is the same as that of the first embodiment, its detailed description is omitted. The operator recording unit 255 records the operator input by the input unit B2. The filter calculation unit 256 uses the operator recorded in the operator recording unit 255 to perform processing for correcting the sensitivity in the axial direction for each data group recorded in the flaw detection data recording unit 251. The calculation data recording unit 257 records the calculation result processed by the filter calculation unit 256.

  Here, as an operator used in the filter calculation unit 256, for example, a matrix operator as a sharpening filter represented by the following formula (2) can be exemplified. According to this operator (matrix), the coefficient with the adjacent channel is 0 (zero), and has a coefficient at a position related to either the odd-numbered channel or the even-numbered channel. Channels can be processed independently and collectively.

  Next, a flaw detection method using the eddy current flaw detection apparatus 2 will be described, but the flaw detection method using the eddy current flaw detection apparatus 2 is not limited to the following modes. The eddy current flaw detection apparatus 2 is different from the flaw detection method of the eddy current flaw detection apparatus 1 described above in that the signal division by the dividing means A3 and the rearrangement by the rearrangement means A5 described in the first embodiment are not performed. . Further, in the eddy current flaw detector 2, information on the axial direction of each channel is recorded in advance in the arithmetic processing means B4. In the present embodiment, it is assumed that an operator for correcting the sensitivity in the axial direction is input in advance.

(Step b1) First, the electromotive force at each measurement position is sequentially measured while switching channels by scanning on the subject s using the multi-coil probe 110. Note that the specific operation of (step b1) is the same as that of (step a2) described above, and is therefore omitted.
(Step b2) Next, the measured value of the electromotive force is collectively calculated using an operator for correcting the sensitivity in the axial direction. Specifically, a flaw detection signal is acquired from the measured electromotive force signal, and this flaw detection signal is A / D converted. Acquisition of the flaw detection signal from the electromotive force measurement value and A / D conversion of the flaw detection signal are performed by the multi-flaw detector 130, and the A / D converted flaw detection signal is used to correct the sensitivity in the axial direction. Arithmetic processing is performed collectively using the child. As said operator, the matrix etc. which are represented by said Formula (2) are applicable, for example.
(Step b3) Next, the calculated calculation result is displayed in association with the measurement position in association with the measurement position. Since the specific operation in (step b3) is the same as that in (step a6) above, a description thereof will be omitted.

<Eddy current flaw detection method>
The eddy current flaw detection method of the present invention is
A plurality of channels in which a pair of excitation coils and detection coils are combined, and the axial direction of the channel axis passing through the central portion of the excitation coil and the central portion of the detection coil is scanned in at least a part of the channels. An eddy current flaw detection method for flaw detection using an eddy current flaw detector provided with a multi-coil probe that intersects at an angle with respect to the direction and at least two crossing angles between the axial direction and the scanning direction are set. ,
Inputting the axial information corresponding to each channel;
Sequentially measuring the electromotive force at each measurement position while switching the channel by scanning on the subject using the multi-coil probe;
Dividing the measured value of the electromotive force into a plurality of data groups having the same axial direction;
A step of independently processing each of the divided data groups using an operator for correcting the sensitivity in the axial direction;
Rearranging the calculation results of the data groups subjected to the calculation processing so as to correspond to the measurement positions;
And displaying the rearranged calculation results in association with the measurement positions.

  As described above, since the eddy current flaw detection method includes the above-described steps, the stripe noise in the image obtained as a flaw detection result can be sufficiently reduced, and the defect can be reliably identified.

  The description of the eddy current flaw detection method is the same as the description of the flaw detection method using the eddy current flaw detection device 1 in the first embodiment of the <eddy current flaw detection device> described above, and thus the first embodiment. The description of is omitted here.

In addition, the present invention has a plurality of channels in which a pair of excitation coils and detection coils are combined, and at least a part of the channels passes through the central portion of the excitation coil and the central portion of the detection coil. Vortex for flaw detection using an eddy current flaw detector provided with a multi-coil probe in which the axial direction of the axis crosses obliquely with respect to the scanning direction and the crossing angle between the axial direction and the scanning direction is set to at least two or more. A current flaw detection method,
Sequentially measuring the electromotive force at each measurement position while switching the channel by scanning on the subject using the multi-coil probe;
A step of collectively calculating the measured value of the electromotive force using an operator for correcting the sensitivity in the axial direction;
An eddy current flaw detection method, comprising: displaying the calculation result obtained by the calculation process in association with the measurement position and corresponding to the calculation result.

  As described above, since the eddy current flaw detection method includes the above-described steps, the stripe noise in the image obtained as a flaw detection result can be sufficiently reduced, and the defect can be reliably identified.

  The description of the eddy current flaw detection method is the same as the description of the flaw detection method using the eddy current flaw detection device 2 in the second embodiment of the above <eddy current flaw detection apparatus>. The description is incorporated and omitted.

  In addition, this invention is not limited to the structure of embodiment mentioned above, is shown by the claim, and intends that all the changes within the meaning and range equivalent to a claim are included. Is done.

  For example, in the first and second embodiments described above, the eddy current flaw detectors 1 and 2 having input means for directly inputting an operator have been described. However, the calculation used from a plurality of already input operators. An eddy current flaw detector provided with an input means for selecting a child and an eddy current flaw detector that applies a predetermined operator as it is without inputting information on the operator are also within the intended scope of the present invention.

  In the above-described embodiment, the multiplexer 120 is exemplified as the means for selecting the excitation coil E and the detection coil D and the channel switching in the flaw detection means A1, but the multiplexer 120 is not particularly limited as long as it has such a function. Eddy current flaw detectors using means other than 120 are also within the intended scope of the present invention.

s object DF defect E exciting coil D detecting coil 1, 2 eddy current flaw detector A1 flaw detector A2 input means A3 dividing means A4 arithmetic processing means A5 rearrangement means A6 display means 110 multicoil probe 112 coil 120 multiplexer 130 multi flaw detector 140 Movement control mechanism 150 Personal computer 160 Input device 170 Monitor

Claims (9)

A plurality of channels in which a pair of excitation coils and detection coils are combined, and the axial direction of the channel axis passing through the central portion of the excitation coil and the central portion of the detection coil is scanned in at least a part of the channels. An eddy current flaw detector comprising a multi-coil probe that intersects at an angle with respect to the direction and at least two intersection angles between the axial direction and the scanning direction are set,
Input means for inputting information in the axial direction corresponding to each channel;
Flaw detection means for sequentially measuring the electromotive force at each measurement position while switching the channel;
A dividing means for dividing the measured value of the electromotive force measured by the flaw detection means into a plurality of data groups having the same axial direction;
Arithmetic processing means for independently processing each data group divided by the dividing means using an operator for correcting sensitivity in the axial direction;
Rearrangement means for rearranging the calculation results of the data groups calculated by the calculation processing means so as to correspond to the measurement positions;
An eddy current flaw detector comprising: display means for displaying the calculation result rearranged by the rearrangement means in association with the measurement position.   2. The eddy current according to claim 1, wherein the input of information in the axial direction in the input means is performed by designating individual channels or by performing a plurality of channels collectively based on regularity. Flaw detection equipment.   3. The eddy current flaw detector according to claim 1, wherein the channel switching in the flaw detection means is performed by a multiplexer.   The eddy current flaw detector according to any one of claims 1 to 3, wherein the arithmetic processing in the arithmetic processing means is processing by a digital filter.   The eddy current flaw detector according to any one of claims 1 to 4, wherein the array rearranged by the rearranging means is a two-dimensional array.   6. The eddy current flaw detector according to claim 1, wherein the display of the calculation result in the display means is a color tone display or a gradation display corresponding to the calculation result. A plurality of channels in which a pair of excitation coils and detection coils are combined, and the axial direction of the channel axis passing through the central portion of the excitation coil and the central portion of the detection coil is scanned in at least a part of the channels. An eddy current flaw detector comprising a multi-coil probe that intersects at an angle with respect to the direction and at least two intersection angles between the axial direction and the scanning direction are set,
Flaw detection means for sequentially measuring the electromotive force at each measurement position while switching the channel;
Arithmetic processing means for collectively calculating the measured value of the electromotive force measured by the flaw detection means using an operator for correcting sensitivity in the axial direction;
An eddy current flaw detector comprising: display means for displaying a calculation result calculated by the calculation processing means in association with the measurement position and displaying a color tone or gradation corresponding to the calculation result. . A plurality of channels combining a pair of excitation coils and detection coils are provided, and at least a part of the channels scans the axial direction of the channel axis passing through the central portion of the excitation coil and the central portion of the detection coil. An eddy current flaw detection method for flaw detection using an eddy current flaw detector provided with a multi-coil probe that intersects at an angle with respect to the direction and at least two crossing angles between the axial direction and the scanning direction are set. ,
Inputting the axial information corresponding to each channel;
Sequentially measuring the electromotive force at each measurement position while switching the channel by scanning on the subject using the multi-coil probe;
Dividing the measurement value of the electromotive force into a plurality of data groups having the same axial direction;
A step of independently performing arithmetic processing on the divided data group using an operator for correcting sensitivity in the axial direction;
Rearranging the computation results of the data groups that have undergone the computation processing so as to correspond to the measurement positions;
An eddy current flaw detection method comprising: displaying the rearranged calculation results in association with the measurement positions. A plurality of channels combining a pair of excitation coils and detection coils are provided, and at least a part of the channels scans the axial direction of the channel axis passing through the central portion of the excitation coil and the central portion of the detection coil. An eddy current flaw detection method for flaw detection using an eddy current flaw detector provided with a multi-coil probe that intersects at an angle with respect to the direction and at least two crossing angles between the axial direction and the scanning direction are set. ,
Sequentially measuring the electromotive force at each measurement position while switching the channel by scanning on the subject using the multi-coil probe;
A step of collectively calculating the measured value of the electromotive force using an operator for correcting the sensitivity in the axial direction;
An eddy current flaw detection method comprising the step of displaying the calculated calculation result in association with the measurement position and corresponding to the calculation result.