JP2019078558A - Reference test piece and supersonic phased array flaw testing method - Google Patents

Abstract

To provide a reference test piece and a supersonic phased array flaw testing method, capable of finely adjusting sensitivity of a supersonic flaw test device having a matrix array probe and checking performances of the matrix array probe.SOLUTION: A reference test piece 10 is for sensitivity adjustment of a supersonic flaw test device used for supersonic flaw test including a matrix array probe 3 formed by two-dimensionally arraying a plurality of ultrasonic elements 3a, and comprises: a flaw detection surface 11 on which the matrix array probe 3 is arranged; and a plurality of flat-bottomed holes 15 formed radially in the test piece with, as centre, ultrasonic wave incident point O of the matrix array probe 3 arranged on the flaw detection surface 11. Respective flat bottom surfaces 15b of the plurality of flat-bottomed holes 15 are arranged facing each other to reflect supersonic wave incident from the matrix array probe 3 through the ultrasonic wave incident point O toward the ultrasonic wave incident point O.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a contrast test strip used for calibration of sensitivity adjustment of an ultrasonic flaw detection test apparatus having a matrix array probe used for ultrasonic phased array flaw detection test and creation of a distance amplitude characteristic curve (DAC line) diagram, etc. The present invention relates to an ultrasonic phased array flaw detection test method.

  The matrix array probe is a probe in which a plurality of ultrasonic elements are two-dimensionally arranged, and a simple grid-like probe in which a plurality of ultrasonic elements are vertically and horizontally arranged is known Besides, an annular array probe in which a plurality of ultrasonic elements are arranged concentrically, a circular array probe in which annular elements are arranged, and the like are known.

  When performing an ultrasonic phased array flaw test using an ultrasonic flaw detector having such a matrix array probe, the matrix array probe is set on the test object, and the matrix array probe is used. By shifting the excitation timing of the plurality of ultrasonic elements, ultrasonic waves are scanned in a plane orthogonal to the measurement line set in the test object, and reflection is reflected back by instructions such as flaws inherent in the test object The waves are received by a plurality of ultrasonic elements, and images are used to evaluate the presence or absence of instructions inside the test object. Such flaw detection tests are widely used to inspect welds in structures such as boilers and nuclear power plants.

  The contrast test pieces used for calibration of sensitivity adjustment of the ultrasonic testing equipment and creation of the distance-amplitude characteristic curve diagram have the overall shape and dimensions determined according to the purpose, and the type, position and dimensions of the introduced flaws And is made of the same or equivalent material as the material of the test object.

  For example, Patent Document 1 describes a standard test piece (STB-A2 defined in JIS standard) similar to the comparison test piece. In this standard test piece, a large number of large and small circular holes are formed in the direction passing through the plate thickness, and some of the circular holes are used to adjust the flaw detection sensitivity.

  A test piece having a circular hole for flaw detection sensitivity adjustment such as this standard test piece, when performing sensitivity adjustment of an ultrasonic flaw detection test device having a matrix array probe, for flaw detection sensitivity adjustment in this test piece A matrix array probe is placed on a flaw detection surface parallel to a circular hole, and each excitation timing of a plurality of ultrasonic elements in the matrix array probe is controlled to be late at the center and to be fast at both sides, The phases of the ultrasonic waves from the ultrasonic elements are aligned (focused) at one point of a circular hole for flaw detection sensitivity adjustment.

  Then, the sensitivity of the flaw detection tester is adjusted so that the reflection amplitude value obtained at this time becomes, for example, 80% on the display of the ultrasonic flaw detection tester, and this is used as the reference sensitivity.

Japanese Patent Application Publication No. 06-138106

  However, in the test piece described above, as shown in FIG. 7, even if the phases of the ultrasonic waves from the respective ultrasonic elements 103a are aligned at one point 115p in the circular hole 115 for flaw detection sensitivity adjustment As the echoes reflected by the surface orthogonal to the traveling direction of the ultrasonic waves emitted from each are most strongly returned to each ultrasonic element 103a, so the phases of the ultrasonic waves from each ultrasonic element 103a are largely shifted As a result, there is a problem that precise sensitivity adjustment of the ultrasonic testing apparatus and performance confirmation of the matrix array probe 103 can not be performed, and solving the problem has been a conventional problem.

  The present invention has been made focusing on the above-mentioned problems, and can perform precise sensitivity adjustment of an ultrasonic flaw detection test apparatus having a matrix array probe, and confirm the performance of the matrix array probe. It is an object of the present invention to provide a contrast test strip and an ultrasonic phased array flaw test method that can be performed.

  In order to achieve the above object, a first aspect of the present invention is a contrast test strip for calibration of an ultrasonic flaw detector having a matrix array probe in which a plurality of ultrasonic elements are two-dimensionally arranged. Inside the test piece centering on the flaw detection surface on which the matrix array probe of the ultrasonic flaw testing apparatus is installed, and the ultrasonic wave incident point of the matrix array probe disposed on the flaw detection surface The flat bottom holes are formed radially, and the flat bottom of each of the plurality of flat bottom holes directs ultrasonic waves from the matrix array probe incident through the ultrasonic incident point toward the ultrasonic incident point In order to reflect, it is set as the structure arrange | positioned facing each other.

  In the second aspect of the present invention, the plurality of flat bottom holes are arranged on the same plane.

  In the third aspect of the present invention, flat bottoms of the plurality of flat bottom holes are arranged on the same line.

  A fourth aspect of the present invention is an ultrasonic phased array flaw detection test method using an ultrasonic flaw detection test device having a matrix array probe, wherein the comparison test piece according to any one of claims 1 to 3 is used. It is configured to include a calibration process of the sonic flaw detection apparatus.

  In the comparison test piece according to the present invention, the matrix array probe of the ultrasonic flaw detector is set on the flaw detection surface, and the respective excitation timings of the plurality of ultrasonic elements in this matrix array probe are controlled, When the phases of the ultrasonic waves from the ultrasonic elements are aligned on the flat bottom of the flat bottom hole, the flat bottom of the flat bottom hole is positive to reflect the ultrasonic waves from the matrix array probe toward the ultrasonic incident point. Since they are arranged with respect to each other, that is, arranged so as to be orthogonal to the traveling direction of the ultrasonic waves, the ultrasonic waves reflected on the flat bottom will return to the matrix array probe with almost no phase shift, Therefore, the sensitivity adjustment of the ultrasonic testing apparatus and the performance confirmation of the matrix array probe can be performed.

  According to the comparison test piece according to the present invention, the sensitivity adjustment of the ultrasonic flaw detection test apparatus having the matrix array probe can be performed, and the performance of the matrix array probe can be confirmed. Effects are brought about.

BRIEF DESCRIPTION OF THE DRAWINGS It is schematic structure explanatory drawing of the ultrasonic flaw detection test apparatus with which the contrast test piece which concerns on this invention is applied at the time of sensitivity adjustment. It is whole perspective explanatory drawing of the contrast test piece which concerns on one Embodiment of this invention. It is an image figure which shows the effect | action of the contrast test piece of FIG. It is partial side view explanatory drawing of the contrast test piece of FIG. It is a distance amplitude characteristic curve (DAC line) figure created based on the standard sensitivity of the ultrasonic flaw detector obtained using the contrast test piece of FIG. It is plane explanatory drawing (a) and cross-sectional explanatory drawing (b) which show the condition which is carrying out the ultrasonic flaw detection test with respect to a welding part by the matrix array probe of ultrasonic flaw detection test equipment. It is an image figure which shows the phase shift of the ultrasonic wave in, when performing sensitivity adjustment with the conventional test piece.

Hereinafter, a comparison test piece according to the present invention will be described based on the drawings.
FIGS. 1 to 5 show an embodiment of a comparative test piece according to the present invention, in which the test object of the ultrasonic flaw testing apparatus to be calibrated with the comparative test piece according to the present invention is shown. The case of a welded portion will be described by way of example.

  As shown in FIG. 1, the ultrasonic testing apparatus 1 has a pulsar receiver 2 having a function of exciting an ultrasonic pulse signal and a receiving function, a matrix array probe 3, and an analog / digital converter (hereinafter referred to as A). A pulse circuit to generate pulse signals to be applied to each of the plurality of ultrasonic elements 3a at a desired timing, and the pulser receiver 2 includes A synchronization circuit is provided which synthesizes each received signal from the ultrasonic element 3a at a desired timing.

  The matrix array probe 3 has a plurality of ultrasonic elements 3a arranged in a matrix in the longitudinal and lateral directions, performs mode conversion of longitudinal waves into transverse waves and performs oblique flaw detection, and is generated by the pulsar receiver 2. The ultrasonic wave generated by the pulse signal is emitted to be incident on the welding portion W and the reflected wave from the inside of the welding portion W is received.

  The reflected waves respectively received by the plurality of ultrasonic elements 3a of the matrix array probe 3 are converted into electric signals, and the reflected waves converted into the electric signals are input in synchronization with the pulsar receiver 2 and synthesized. The synthesized analog signal is converted into a digital signal by the A / D converter 4 and signal processed by the arithmetic unit 5.

  The arithmetic unit 5 includes various processing circuits such as a control circuit and an image processing circuit. In the arithmetic unit 5, the above-mentioned circuits determine the presence or absence of an instruction and evaluate the instruction height and the like.

  The monitor 6 as an output device displays the visualized image of the received waveform acquired by processing the reflected wave in the operation unit 5, and the presence or absence of the instruction F in the welding portion W and the instruction F in the welding portion W Indication information such as properties including the position and height (the length in the depth direction of the welding portion W) in the case of being displayed is displayed.

  In this ultrasonic testing apparatus 1, the delay timing of the pulser receiver 2 controls the excitation timing of the ultrasonic elements 3a adjacent to each other in the matrix array probe 3 to be slightly delayed from one end side to the other end side. The propagation direction of the ultrasonic wave is inclined with respect to the flaw detection surface Sa of the base material S. The control of changing the excitation timing of the adjacent ultrasonic element 3a little by little to change the direction of propagation of the ultrasonic wave to a direction (desired direction) to be assumed is scan angle control, so-called steering control. At this time, if the delay time is changed stepwise, that is, if the propagation direction of the ultrasonic wave is changed stepwise, the sector scan is performed.

  On the other hand, when the excitation timings of the plurality of ultrasonic elements 3a arranged in a lattice of the matrix array probe 3 are controlled to be quick at the both ends and delayed at the center by the delay circuit of the pulsar receiver 2, each ultrasonic element The phases of the ultrasonic waves from 3a are aligned at the focusing point. The control of focusing at a (desired) focusing point assuming this ultrasonic wave is focusing point control, so-called focusing control of focusing, and by arbitrarily setting the excitation timing of the ultrasonic element 3a, the distance to the focusing point The sector scan can be performed by swinging the assumed focusing point to the left and right.

  As shown in FIG. 2, the comparison test piece 10 used for calibration such as adjustment of sensitivity of the ultrasonic testing apparatus 1 and creation of a distance-amplitude characteristic curve is a welding object to be tested by the ultrasonic testing apparatus 1. It is made of the same material as the part W.

The comparison test piece 10 includes a flaw detection surface 11 on which the matrix array probe 3 is installed, a bottom surface 12 opposite to the flaw detection surface 11, and an arc surface 13 of radius R located between the flaw detection surface 11 and the bottom surface 12 The center of the circular arc surface 13 is set as the ultrasonic wave incident point O of the matrix array probe 3 on the flaw detection surface 11.
The surface located between the flaw detection surface 11 and the bottom surface 12 is not limited to the arc surface 13, and may be a spherical surface (a part of a spherical surface) or a plane with a radius R. May be

  Further, the comparison test piece 10 is positioned radially on the same surface A from the ultrasonic incident point O of the matrix array probe 3 disposed on the flaw detection surface 11 toward the circular arc surface 13. A plurality of formed flat bottom holes 15 are provided. One end of each of the flat bottom holes 15 is formed as an opening 15a in the arc surface 13, and the other end is formed as a flat bottom surface 15b.

  The flat bottom hole 15 is a circular hole having a diameter of a few mm, and for example, a hole is drilled from the side of the arc surface 13 toward the ultrasonic incident point O, and then the flat bottom surface 15b is finished by an end mill.

  In this case, the flat bottom surfaces 15b of the plurality of flat bottom holes 15 are arranged on the same line B, and reflect the ultrasonic waves from the ultrasonic wave incident point O toward the ultrasonic wave incident point O. It is formed to be orthogonal to the traveling direction of the ultrasonic wave. That is, as shown in FIG. 3, the flat bottom surface 15b of the flat bottom hole 15 has a plurality of supersonic waves so that the ultrasonic waves whose phases are aligned from the plurality of ultrasonic elements 3a of the matrix array probe 3 are strongly reflected. It is formed to face the acoustic wave element 3a.

  The distance Y between the line B on which each flat bottom surface 15b of the plurality of flat bottom holes 15 is positioned and the ultrasonic incident point O is the distance between the welding portion W and the matrix array probe 3 in the actual ultrasonic flaw detection test. It is determined in consideration of the distance and the dimensions of the matrix array probe 3.

  Next, the procedure of the ultrasonic phased array flaw detection test method for the welded portion W using the above-described ultrasonic flaw detection apparatus 1 will be described.

  First, prior to the ultrasonic flaw detection test on the weld portion W, sensitivity adjustment of the ultrasonic flaw detection apparatus 1 and creation of a distance amplitude characteristic curve diagram are performed using the above-mentioned comparison test piece 10 (calibration step).

  That is, as shown in FIG. 4, the matrix array probe 3 is set on the ultrasonic wave incident point O set on the flaw detection surface 11 of the comparison test piece 10, and a plurality of lattice array probes 3 are arrayed in the matrix array probe 3. In the flat bottom holes 15 (15h1 to 15h5) arranged in the depth direction in the inside of the comparison test piece 10 by controlling the excitation timing of the ultrasonic element 3a to be quick at the both ends and to be late at the center. The phases of the ultrasonic waves from the ultrasonic elements 3a are aligned (focused) on the flat bottom surfaces 15b.

  Then, the sensitivity of the apparatus is adjusted so that the reflection amplitude value from any flat bottom 15b of the flat bottoms 15b in the flat bottom holes 15 (15h1 to 15h5) becomes, for example, 80% on the monitor 6, It is sensitivity.

  Next, based on the reference sensitivity, each of the reflected waves that are reflected and returned by each flat bottom surface 15b in the flat bottom holes 15 (15h1 to 15h5) are received by the plurality of ultrasonic elements 3a and synthesized to obtain reception waveforms respectively And measure each reflection amplitude value.

  Subsequently, as shown in FIG. 5, the relationship between the depths of the flat bottom surface 15b of the flat bottom holes 15 (15h1 to 15h5) and the reflection amplitude value from each flat bottom surface 15b is graphed to show each flat bottom surface 15b. A line connecting reflection amplitude values for each depth is defined as the H line, and a line 6 dB below (1/2 reflection amplitude value) from the H line is defined as the M line, and 6 dB below the M line. A line is defined as an L line. That is, a distance amplitude characteristic curve diagram is created.

Thus, after creating the distance-amplitude characteristic curve diagram, an ultrasonic flaw test is performed on the weld portion W to be tested.
That is, as shown in FIG. 6, the matrix array probe 3 is set at a position separated by a distance Y from the weld line L of the weld portion W on the flaw detection surface Sa of the base material S. At this time, a contact medium (not shown) such as glycerin paste or machine oil is applied to the flaw detection surface Sa to prevent the formation of an air layer between the matrix array probe 3 and the flaw detection surface Sa.

  In this state, flaw detection is started, and in the plane orthogonal to the weld line L along the weld portion W, the delay circuit of the pulsar receiver 2 excites the plurality of ultrasonic elements 3a arranged in a grid of the matrix array probe 3 The timing is controlled so as to be fast at both end sides and late at the center, and in order to move the focusing point in the depth direction of the welding portion W, the ultrasonic wave is subjected to three-dimensional sector scan.

  Then, for each scanning angle within the sector scanning range of the ultrasonic waves, the reflected waves that are reflected back in the welding portion W are received and synthesized by the plurality of ultrasonic elements 3a, thereby acquiring reception waveforms.

  Three-dimensional sector scan of this ultrasonic wave is carried out each time the matrix array probe 3 is moved along the welding line L in the left direction (the direction of the arrow in FIG. The ultrasonic flaw detection test on the weld W is performed on both the + side and the-side with the weld W in between.

  In the reception waveform of the reflected wave acquired by the sector scan of the ultrasonic wave, the instruction Fa of the reflection amplitude value exceeding the instruction presence / absence determination threshold (the instruction presence / absence determination threshold according to the depth inside the welded portion W) set in advance , Fb, and Fc, the depths and reflection amplitude values of these instructions Fa, Fb, and Fc are applied to the distance amplitude characteristic curve diagram of FIG. 5 and compared.

  In the distance-amplitude characteristic curve of FIG. 5, for example, when the determination criterion is L line or more, it is determined that all the instructions Fa, Fb, and Fc are rejection defects, and the determination criterion is M line or more In this case, it is determined that only the instruction Fa is a failure defect, and it is determined that the instructions Fb and Fc are pass defects.

  Then, if the three-dimensional sector scan of ultrasonic waves is performed by stepping along the welding line L at a constant interval, the entire volume of the instruction F can be grasped, and the monitor 6 intersects with the welding line L The indicated length obtained by integrating the results of the three-dimensional sector scanning performed on each cross section is displayed.

  As described above, in the comparison test piece 10 according to the present embodiment, the matrix array probe 3 is set on the flaw detection surface 11, and the phases of the ultrasonic waves from the respective ultrasonic elements 3a of the matrix array probe 3 Are aligned on the flat bottom surface 15b of the flat bottom hole 15, this flat bottom surface 15b is disposed to face the ultrasound incident point O so as to reflect the ultrasound from the matrix array probe 3 Therefore, since the ultrasonic waves reflected by the flat bottom surface 15b return to the matrix array probe 3 with almost no phase shift since they are arranged to be orthogonal to the traveling direction of the ultrasonic waves, as a result, The sensitivity adjustment of the sonic testing apparatus 1 and the performance confirmation of the matrix array probe 3 can be performed.

  Further, in the comparison test piece 10 according to the present embodiment, a plurality of flat bottom holes 15 radially formed from the ultrasonic wave incident point O of the matrix array probe 3 toward the arc surface 13 are positioned on the same surface A In addition, since the flat bottoms 15b of the flat bottom holes 15 are positioned on the same line B, molding of the plurality of flat bottom holes 15 becomes easy, and calculation is performed. The calculation relating to the calibration of part 5 is simplified.

  On the other hand, in the ultrasonic phased array flaw detection test method according to the present embodiment, the sensitivity adjustment of the ultrasonic flaw detection apparatus 1 and the performance confirmation of the matrix array probe 3 are performed prior to the flaw detection test of the welded portion W. Thus, the determination of the presence or absence of the instruction F can be accurately made.

  In the above embodiment, the plurality of flat bottom holes 15 of the comparison test piece 10 are positioned on the same surface A, but the present invention is not limited to this. It may be arranged with an angle.

  Moreover, in the said embodiment, although each flat bottom face 15b of several flat bottom holes 15 in the comparison test piece 10 is mutually located on the same line B, it is not limited to this, Several flat bottoms The flat bottom surfaces 15b of the holes 15 may be formed apart from the line B.

  Furthermore, although the case where the test object of the ultrasonic phased array flaw detection test method according to the present invention is the welded portion W is shown in the above embodiment, the present invention is not limited to this. You may use for the flaw detection test of large sized structures, such as a plant.

  The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

1 ultrasonic flaw testing apparatus 3 matrix array probe 3a ultrasonic element 10 contrast test piece 11 flaw detection surface 15 flat bottom hole 15b flat bottom surface O ultrasonic wave incident point of matrix array probe

Claims (4)

A contrast test strip for calibration of an ultrasonic flaw detector having a matrix array probe in which a plurality of ultrasonic elements are arranged two-dimensionally.
A flaw detection surface on which the matrix array probe of the ultrasonic flaw detection test device is installed;
It has a plurality of flat bottom holes formed radially inside a test piece around an ultrasonic wave incident point of the matrix array probe arranged on the flaw detection surface,
Each flat bottom surface of the plurality of flat bottom holes is arranged to face each other so as to reflect ultrasonic waves from the matrix array probe incident through the ultrasonic incident point toward the ultrasonic incident point. Test pieces.   The contrast test strip according to claim 1, wherein the plurality of flat bottom holes are located on the same plane as each other.   The contrast test strip according to claim 2, wherein flat bottoms of the plurality of flat bottom holes are located on the same line with each other. In an ultrasonic phased array flaw test method using an ultrasonic flaw tester having a matrix array probe,
The ultrasonic phased array flaw test method including the calibration process of the said ultrasonic flaw tester by the contrast test piece in any one of Claims 1-3.

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