JP4699242B2 - Ultrasonic probe coupling check method and computer program - Google Patents

Description

  The present invention relates to an automatic ultrasonic flaw detector and a method for processing ultrasonic flaw detection data, and in particular, a cup between an ultrasonic probe and an object of an automatic ultrasonic flaw detector that automatically scans an ultrasonic probe. It relates to the technology for checking the ring.

  When performing an inspection of an object (for example, a bridge) with an ultrasonic probe, it is necessary to check the coupling between the ultrasonic probe and the object. If ultrasonic flaw detection is performed in a state where the coupling is not correctly taken, incidence of ultrasonic waves on the subject and detection of reflected waves from the subject are not performed correctly, and therefore correct flaw detection data cannot be obtained.

  One method for confirming the coupling between the ultrasound probe and the subject is to adjust the contact state between the ultrasound probe and the subject while confirming the reflected wave waveform by visual inspection by an engineer. is there. An engineer with sufficient experience can confirm that the ultrasonic probe and the subject are correctly coupled by visually confirming the waveform of the reflected wave.

  However, when the flaw detection data is acquired by automatically scanning the ultrasonic probe, it is not preferable to visually confirm the coupling between the ultrasonic probe and the subject. When scanning the ultrasound probe automatically, the coupling may be improper during scanning for any reason, so the ultrasound at each scan position (ie, in each cross section perpendicular to the scan direction). It is necessary to confirm the coupling between the probe and the subject. However, it takes a lot of labor to visually confirm the coupling between the ultrasonic probe and the subject at all scanning positions (that is, all cross sections).

  Japanese Industrial Standard JIS Z 3070 discloses an automatic ultrasonic flaw detection method for checking coupling using forest echoes (pages 6 to 7 and FIG. 10). However, the relevant part of the Japanese Industrial Standard JIS Z 3070 only describes that “the average echo height in the echo recording gate is used as a coupling monitoring signal”. Japanese Industrial Standard JIS Z 3070 does not specifically describe how to determine the coupling monitoring signal, and also provides a specific criterion for determining whether or not the coupling is correctly taken. Not a thing.

From such a background, when automatically scanning an ultrasonic probe to acquire flaw detection data, a technique for confirming that the ultrasonic probe and the subject are correctly coupled is known. Offer is desired.
JIS Z 3070 Method for automatic ultrasonic testing of steel welds June 30, 1998, first printing Japan Standards Association

  An object of the present invention is to provide a technique for confirming that an ultrasonic probe and a subject are correctly coupled when automatically scanning the ultrasonic probe to acquire flaw detection data. It is to provide.

  In order to achieve the above object, the present invention employs the means described below. In the description of technical matters constituting the means, in order to clarify the correspondence between the description of [Claims] and the description of [Best Mode for Carrying Out the Invention] Number / symbol used in the best mode for doing this is added. However, the added number / symbol should not be used to limit the technical scope of the invention described in [Claims].

The ultrasonic probe coupling check method according to the present invention includes:
(A) In a state where the coupling between the probe (6) and the control structure is obtained, ultrasonic waves are incident on the control structure by the probe (6), and the control is performed. Obtaining an echo height at each position of a predetermined healthy portion (21) of the structural body;
(B) determining a threshold from the echo height at each position of the healthy part (21);
(C) An ultrasonic wave is incident on the subject (2) by the probe (6) while automatically scanning the probe (6), and within the predetermined monitoring range (22) of the subject (2). Obtaining an echo height at each position of
(D) By comparing the echo height and the threshold value at each position within the predetermined monitoring range (22) with the probe (6) while being automatically scanned, Determining whether or not the coupling with the specimen (2) has been correctly maintained. In one embodiment, by automatically scanning the probe (6), the echo height is acquired for each of the plurality of cross sections of the subject (2), and the coupling is correctly determined from the acquired echo height. It is determined whether or not it has been maintained.

  In this case, it is preferable that the average value of the echo height at each position of the healthy part (21) is determined as the threshold value.

  The control structure and the subject (2) are preferably the same, that is, the subject (2) itself is preferably used to determine the threshold value. In this case, it is preferable that the monitoring range (22) defined in each of the plurality of cross sections and the healthy part (21) are determined to be at the same position.

  The control structure and the subject (2) can be different structures. In this case, it is preferable that the control structure is formed of the same material as that of the subject or in the same manufacturing process.

A computer program according to the present invention provides:
(E) Control obtained by injecting ultrasonic waves into the control structure by the probe (6) in a state where the coupling between the probe (6) and the control structure is obtained. From the flaw detection data for obtaining the echo height at each position of the predetermined healthy portion (21) of the reference structure;
(F) determining a threshold from the echo height at each position of the healthy part (21);
(G) From the flaw detection data obtained by applying ultrasonic waves to the subject (2) by the probe (6) while automatically scanning the probe (6), a predetermined value of the subject (2) is obtained. Obtaining an echo height at each position within the monitoring range (22);
(H) While automatically scanning the probe (6), the probe (6) is compared with the threshold value by comparing the echo height at each position within the predetermined monitoring range (22). And a step of determining whether or not the coupling with the subject (2) is correctly maintained.

  The present invention provides a technique for confirming that the ultrasonic probe and the subject are correctly coupled when the ultrasonic probe is automatically scanned to acquire flaw detection data. The Furthermore, the coupling confirmation operation can be made efficient by automatically confirming the coupling by the arithmetic unit.

  FIG. 1 is a diagram showing an example of the configuration of an automatic ultrasonic flaw detector 1 to which the ultrasonic probe coupling check method of the present invention is applied. In the present embodiment, the automatic ultrasonic flaw detector 1 using a probe having a predetermined number of parallel ultrasonic transducers electronically scans the oscillation position of the ultrasonic wave at a fixed flaw detection refraction angle. 2 flaw detection is performed. The subject 2 to be flawed is two steel plates 3 and 4 which are butt welded. In the following, a description will be given of a case where flaw detection is performed on the welded portion 5 of the steel plates 3 and 4 and the periphery thereof, but it will be obvious to those skilled in the art that the subject 2 is not limited to such a structure.

  The automatic ultrasonic flaw detector 1 according to this embodiment includes a probe 6, a scanning device 7 that scans the probe 6 in a desired scanning direction, a calculation device 8, and a display device 9. In the present embodiment, the scanning direction is determined in the direction along the weld line of the steel plates 3 and 4. In the following description, it should be noted that an xyz orthogonal coordinate system is used in which the scanning direction is the z-axis direction, the direction perpendicular to the scanning direction and parallel to the surface of the steel plate 3 is the x-axis direction.

  The probe 6 makes an ultrasonic wave incident on the subject 2, receives a reflected wave from the subject 2, and generates an electrical signal corresponding to the reflected wave. A wedge-shaped spacer 10 is joined to the surface of the probe 6, and the probe 6 is supported obliquely with respect to the surface of the steel plate 3 by the wedge-shaped spacer 10. The ultrasonic beam generated by the probe 6 is incident on the steel plate 3 through the spacer 10, and the reflected wave of the ultrasonic beam reaches the probe 6 from the steel plate 3 through the spacer 10.

  The probe 6 is composed of a plurality of ultrasonic transducers arranged in a line in the xy cross section, and the probe 6 can function as a phased array by itself. That is, the probe 6 can make an ultrasonic beam incident from a desired position on the contact surface between the probe 6 and the spacer 10 in a desired direction in a cross section parallel to the xy plane of the subject 2. It is configured. The path of an ultrasonic beam in a cross section of the subject 2 is a position where the ultrasonic beam is emitted from the probe 6 (that is, the oscillation of ultrasonic waves formed by a predetermined number of selected ultrasonic transducers) The ultrasonic oscillation source formed by the selected predetermined number of ultrasonic transducers is determined by the source (virtual probe) and the incident direction of the ultrasonic beam.

  The scanning device 7 includes a rail 11 and a probe holding mechanism 12. The rail 11 extends in the scanning direction, that is, the direction of the weld line of the subject 2. The probe holding mechanism 12 holds the probe 6. The probe holding mechanism 12 is placed on the rail 11 so as to be movable in the flaw detection direction, and the probe 6 is scanned by moving the probe holding mechanism 12 on the rail 11. Is called. The position in the scanning direction of the probe 6 can be detected by an encoder (not shown) provided on the rail 11.

  The calculation device 8 controls the probe 6 and performs various calculations for performing a flaw detection on the subject 2. Specifically, the arithmetic unit 8 supplies an electric signal to the probe 6 to cause the probe 6 to generate an ultrasonic beam. Furthermore, the arithmetic unit 8 stores flaw detection data, which is data indicating the waveform of the reflected wave received by the probe 6, in a storage device (not shown). The flaw detection data includes A scope data (that is, reflected wave waveform data) for each focal row of each cross section of the subject 2, and is used to detect a defect existing in the subject 2. The arithmetic device 8 further has a function of generating various ultrasonic images from the flaw detection data, that is, an A scope image, a B scope image, a C scope image, and a D scope image, and displaying them on the display device 9.

  The configuration of the automatic ultrasonic flaw detector 1 is not limited to the one described above, and a square scanning automatic ultrasonic flaw detector as described in JIS Z3070 is used as the automatic ultrasonic flaw detector 1. It will be obvious to those skilled in the art.

  As described above, in order to correctly perform the flaw detection of the subject 2, the coupling between the probe 6 and the subject 2 is properly maintained while the probe 6 is automatically scanned. It is necessary to confirm that. For this reason, in this embodiment, a coupling check is performed according to the following procedure.

  Referring to FIG. 2, in the coupling check method of the present embodiment, control flaw detection data is acquired before performing automatic flaw detection on subject 2 (step S01). The control flaw detection data is flaw detection data used for determining a threshold value for the coupling check, and it is a technique that the coupling between the probe 6 and the subject 2 is correctly maintained. It is acquired in a state confirmed by visual inspection. When the control flaw detection data is collected, an ultrasonic image is displayed on the display device 9, and the engineer correctly maintains the coupling between the probe 6 and the subject 2 from the displayed ultrasonic image. Make sure that you are leaning.

  As shown in FIG. 3, the flaw detection data for control is collected for a certain section of the subject 2 and at least for a range including the healthy portion 21 defined in advance in the section. The focal range scanning range and the ultrasonic beam path from which the control flaw detection data are collected are determined so as to cover at least the whole healthy portion 21. As the healthy part 21, a part that is considered to have no flaw is selected. It is empirically possible to consider a part where no flaw exists from the shape of the subject 2. The healthy portion 21 is selected so as to be separated from the front surface 2 a, the back surface 2 b, and the welded portion 5 of the subject 2. Since the healthy part 21 is a part that does not include any flaws, the echoes obtained from each position of the healthy part 21 are all forest echoes.

  As shown in FIG. 2, after collecting the control flaw detection data, a threshold value is determined from the control flaw detection data (step S02). More specifically, the arithmetic unit 8 extracts the echo height of the echo obtained from each position of the healthy part 21 from the control flaw detection data, and calculates the average value of the echo heights. The average value is determined as a threshold value.

  Subsequently, automatic inspection of the subject 2 is performed (step S03). The probe 6 is automatically scanned in a scanning direction defined in parallel to the weld line, whereby flaw detection data is acquired for a plurality of cross sections of the subject 2.

  After the automatic flaw detection is performed, a coupling check is performed using the threshold value determined in step S02 (step S04). As shown in FIG. 4, a monitoring range 22 is set in advance for the subject 2, and the arithmetic unit 8 performs automatic flaw detection on data indicating the echo height at each position in the monitoring range 22. Extract from the obtained flaw detection data. Furthermore, the arithmetic unit 8 compares the data indicating the echo height at each position in the monitoring range 22 with the threshold value obtained in step S02, and performs a coupling check based on the comparison result.

  Specifically, whether or not the coupling between the probe 6 and the subject 2 has been correctly maintained when acquiring flaw detection data for a focal law with a certain cross section is determined within the monitoring range 22 of the focal law. This is based on the number of positions where the echo height exceeds the threshold. When there are a predetermined number or more of positions where the echo height exceeds a threshold value within the focal range monitoring range 22 having a certain cross section, the arithmetic unit 8 can acquire the focal range of the probe 6 when acquiring the flaw detection data of the focal row. It is determined that the coupling between the ultrasonic incident position by the low and the subject 2 is correctly maintained. Otherwise, the arithmetic unit 8 determines that a coupling failure has occurred.

  For example, as shown in FIG. 5A, when a predetermined number or more of positions where the echo height exceeds the threshold value appear in the focal scope A scope data having a certain cross section, the arithmetic unit 8 Judge that the ring was kept correctly. On the other hand, as shown in FIG. 5B, when the number of positions where the echo height exceeds the threshold value is less than the predetermined number (in FIG. 5B, the number of positions where the echo height exceeds the threshold value is 0), The arithmetic unit 8 determines that a coupling failure has occurred when acquiring the flaw detection data of the focal law.

  The monitoring range 22 of each cross section is allowed to be determined at a position different from the sound portion 21 of the cross section from which the control flaw detection data is collected. However, it is preferable that the monitoring range 22 and the healthy part 21 of each cross section are determined at the same position. That is, the projection of the monitoring range 22 of each cross section onto the xy plane is preferably the same range as the projection of the sound portion 21 onto the xy plane. By determining the monitoring range 22 in this way, the height of the forest echoes appearing in the flaw detection data obtained during the automatic flaw detection with the coupling properly maintained, and the forest echoes appearing at the control flaw detection data positions. Can be made the same height. This is suitable for checking the coupling reliably.

  The control flaw detection data can be acquired not from the subject 2 but from a structure formed of the same material as the subject 2 or a structure manufactured in the same manufacturing process as the subject 2. . Since the forest echo is generally determined by the material, the flaw detection data is acquired from another structure formed of the same material as the subject 2 or another structure manufactured in the same manufacturing process. However, it is possible to determine a generally appropriate threshold value. However, obtaining the flaw detection data using the subject 2 itself to be examined is preferable in that the threshold value can be determined even if there are variations in materials and manufacturing processes.

  In this embodiment, the coupling check is performed after the automatic flaw detection is completed. However, the coupling check can be performed for each cross section and each focal row while the automatic flaw detection is performed. is there.

  The coupling check can also be performed off-line. In other words, the flaw detection data obtained in step S01 and the flaw detection data obtained by automatic flaw detection in step S03 can be transferred to another arithmetic device, and the coupling check can be performed by the other arithmetic device. is there. In this case, a program for executing steps S02 and S04 is installed in the other arithmetic device, and a coupling check is performed by this program.

FIG. 1 is a diagram showing a configuration of an automatic ultrasonic flaw detector used in an embodiment of the present invention. FIG. 2 is a flowchart showing a coupling check procedure performed in the present embodiment. FIG. 3 is a cross-sectional view showing a procedure for collecting control flaw detection data. FIG. 4 is a cross-sectional view showing a procedure for collecting flaw detection data by automatic flaw detection. FIG. 5A is a graph showing an example of A scope data when the coupling is good. FIG. 5B is a graph showing an example of A scope data when the coupling is bad.

Explanation of symbols

1: Automatic ultrasonic flaw detector 2: Subject 3, 4: Steel plate 5: Welded part 6: Probe 7: Scanning device 8: Arithmetic device 9: Display device 10: Spacer 11: Rail 12: Probe holding mechanism 21: Healthy part 22: Monitoring range

Claims (6)

(A) In a state where the coupling between the probe and the control structure is obtained, ultrasonic waves are incident on the control structure by the probe, and a predetermined structure of the control structure is obtained. Obtaining an echo height at each position of the healthy part;
(B) determining a threshold value from the echo height at each position of the healthy part;
(C) obtaining an echo height at each position within a predetermined monitoring range of the subject by causing an ultrasonic wave to be incident on the subject by the probe while automatically scanning the probe; ,
(D) By comparing the echo height and the threshold value at each position within the predetermined monitoring range, the probe and the subject are scanned while the probe is automatically scanned. Determining whether or not the coupling between the two has been maintained correctly ,
In the step (C), the echo height is acquired for each of the plurality of cross sections of the subject, and the monitoring range and the healthy portion defined in each of the plurality of cross sections are at the same position. The ultrasonic probe coupling check method is specified as follows . The ultrasonic probe coupling check method according to claim 1,
The ultrasonic probe coupling check method, wherein the threshold value is determined to coincide with an average value of the echo height at each position of the healthy part. The coupling check method according to claim 1,
The method for checking coupling of an ultrasonic probe, wherein the control structure and the subject are the same. The ultrasonic probe coupling check method according to claim 1,
The method for checking coupling of an ultrasonic probe, wherein the control structure is made of the same material as the subject. The ultrasonic probe coupling check method according to claim 1,
The control structure is an ultrasonic probe coupling check method in which the control structure is formed in the same manufacturing process as the subject. (E) From the flaw detection data for comparison obtained by injecting ultrasonic waves to the reference structure by the probe in a state where the coupling between the probe and the reference structure is obtained, Obtaining an echo height at each position of a predetermined healthy portion of the control structure;
(F) determining a threshold from the echo height at each position of the healthy part;
(G) Echo at each position within a predetermined monitoring range of the subject from flaw detection data obtained by making the probe impinge on the subject while automatically scanning the probe. Obtaining the height; and
(H) By comparing the echo height and the threshold value at each position within the predetermined monitoring range, the probe and the object are scanned while the probe is automatically scanned. Determining whether or not the coupling between the two was correctly maintained ,
In the step (G), the echo height is acquired for each of the plurality of cross sections of the subject, and the monitoring range and the healthy portion defined in each of the plurality of cross sections are at the same position. A computer program that is prescribed as follows .

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