JP2016027321A - Ultrasonic inspection method and probe installation jig - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic inspection method and a probe installation fixture capable of improving accuracy for consistency in correlation processing and ensuring more improved inspection accuracy.SOLUTION: An ultrasonic inspection method includes: an SH guide wave transmission step of transmitting an SH guide wave W1 toward a pipe P2 by a first transmission-reception probe 2 and a second transmission-reception probe 3; a reference wave reception step of receiving the SH guide wave W1 transmitted from the first transmission-reception probe 2 and the second transmission-reception probe 3 as a reference wave W3 by a reception probe 4; a reflection wave reception step of receiving a reflection wave W2 from an inspection object by the first transmission-reception probe 2 and the second transmission-reception probe 3; a correlation processing step of performing correlation processing on the basis of the reference wave W3 received by the reception probe 4 and the reflection wave W1 received by the first transmission-reception probe 2 and the second transmission-reception probe 3; and an output step of outputting a correlation wave W4 obtained in the correlation processing step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultrasonic inspection method and a probe installation jig.

  2. Description of the Related Art Conventionally, in the inspection of corrosion of a portion that is difficult to visually recognize, such as an embedded object or a shield, it is known to transmit an ultrasonic wave to an inspection object and receive a reflected wave to inspect the corrosion. In order to improve inspection accuracy, a method to improve the output level (energy) and directivity of ultrasonic waves so that ultrasonic waves of sufficient intensity propagate, and signal identification by appropriately removing noise from reflected waves, etc. There are ways to improve the performance.

  As a method for improving the output level and directivity of ultrasonic waves, it is conceivable to increase the size of a transmission / reception probe that transmits and receives ultrasonic waves.

  As a method for improving signal discrimination, a pulse compression method based on correlation processing is known. In the ultrasonic diagnostic apparatus disclosed in Patent Document 1, a compression process is performed on the generated chirp wave to output a chirp wave compression signal, and an SH wave is generated based on the chirp wave compression signal and propagated in the subject. Techniques for making them disclosed are disclosed. In this technique, the chirp wave is subjected to a Hamming window function process before the compression process in order to reduce noise.

JP 2011-047763 A

  By the way, when transmitting an ultrasonic wave to a test object, there is a difference between an electric signal waveform controlled by a waveform generator or the like and instructed to be transmitted to the probe, and a propagation waveform that actually propagates through the test object. Therefore, there is room for improvement in the accuracy of consistency when correlation processing with a measurement waveform is performed using an electric signal waveform different from the actual propagation waveform as a reference waveform.

  The present invention has been made in view of the above, and an object of the present invention is to propose an ultrasonic inspection method and a probe installation jig in which the accuracy of consistency in correlation processing is improved and the inspection accuracy is further improved. And

In order to solve the above-mentioned problems and achieve the object, in the ultrasonic inspection method according to the present invention,
(1) An SH guide wave transmission step for transmitting an SH guide wave toward an inspection object by the measurement transmission / reception probe, and the SH guide wave transmitted from the measurement transmission / reception probe by the reception probe. A reference wave receiving step for receiving a reflected wave from the inspection object by the measurement transmission / reception probe, the reference waveform received by the reception probe, A correlation processing step of performing a correlation process based on the reflected wave received by the measurement transmission / reception probe; and an output step of outputting a correlation waveform obtained by the correlation processing step. .

  (2) In the ultrasonic inspection method of (1) above, it is preferable that a plurality of the transmission / reception probes for measurement are arranged in parallel in the propagation direction of the SH guide wave.

  (3) Further, in the ultrasonic inspection method according to (1) or (2), the transmission / reception probe for measurement and the reception probe are placed in a direction different from a propagation direction of the SH guide wave to be inspected. A moving step that moves, wherein the inspection object is a pipe, and a propagation direction of the SH guide wave coincides with an axial direction of the pipe, and the SH at a predetermined location on the outer peripheral surface of the inspection object After performing the guide wave transmitting step, the reference wave receiving step, and the reflected wave receiving step, repeating the moving step to move the outer peripheral surface of the inspection object in the circumferential direction, the inspection object Is preferably inspected over the entire circumference.

  (4) A probe installation jig according to the present invention is used in the ultrasonic inspection method according to any one of (1) to (3), and the transmission / reception probe for measurement and the reception probe are A probe installation jig that is detachably installed on an inspection target, the first support frame that supports the measurement transmission / reception probe in a state of being pressed against the inspection target, and the reception probe, A second support frame that supports the SH guide wave transmitted from the measurement transmission / reception probe in a state of being pressed against the inspection object, and the second support frame is the first support frame. The measurement transmitting / receiving probe supported by the first support frame that has received the reflected wave from the inspection object, and the second support frame that has received the SH guide wave as a reference waveform Supported by the receiving probe The spacing a predetermined distance, characterized in that.

  (5) In the probe installation jig according to (4), the first support frame supports a plurality of the transmission / reception probes for measurement in parallel in the propagation direction of the SH guide wave, The second support frame preferably supports the reception probe positioned on the center line of the plurality of measurement transmission / reception probes.

  (6) In the probe installation jig according to (4) or (5), it is preferable that the second support frame is slidably disposed with respect to the first support frame. .

  In the ultrasonic inspection method according to the present invention, the SH transmission / reception probe transmits the SH guide wave toward the inspection target, and the reference waveform received by the reception probe and the measurement transmission / reception probe receive the reference waveform. Correlation processing is performed based on the reflected wave. As a result, the correlation processing is performed based on the reference waveform that is actually propagated through the inspection target and received by the reception probe, so that the accuracy of consistency in the correlation processing is improved, the signal identification is improved, and the inspection accuracy is further improved. There is an effect of improving.

  Further, the probe installation jig is a measurement probe supported by a first support frame in which a measurement transmission / reception probe and a reception probe are detachably installed on an inspection target and a reflected wave from the inspection target is received. The interval between the transmission / reception probe and the reception probe supported by the second support frame that receives the SH guide wave as a reference waveform is a predetermined distance. Therefore, in the ultrasonic inspection method, there is an effect that the transmission / reception probe for measurement and the reception probe can be easily attached to and detached from the inspection target.

FIG. 1 is a schematic diagram illustrating a state in which corrosion of abutment pipes is inspected by the ultrasonic inspection method according to the first embodiment. FIG. 2 is a block diagram showing the ultrasonic inspection apparatus. FIG. 3 is a side view of the probe installation jig. FIG. 4 is a plan view of the probe installation jig. FIG. 5 is a cross-sectional view of the probe installation jig. FIG. 6 is a flowchart showing signal processing in the ultrasonic inspection method. FIG. 7 is a flowchart showing an ultrasonic inspection method. FIG. 8 is a flowchart showing a measurement processing procedure of the ultrasonic inspection method. FIG. 9 is a flowchart showing the evaluation processing procedure of the ultrasonic inspection method. FIG. 10 is a diagram for explaining an output result obtained by the ultrasonic inspection method. FIG. 11 is a diagram illustrating an output result obtained by the ultrasonic inspection method. FIG. 12 is a schematic diagram illustrating signal processing in the ultrasonic inspection method. FIG. 13 is a schematic view showing a test body used for confirming the effect of the ultrasonic inspection method. FIG. 14 is a diagram for explaining signal discrimination in a conventional ultrasonic inspection method. FIG. 15 is a diagram for explaining signal discrimination in the ultrasonic inspection method. FIG. 16 is a diagram for explaining the directivity in the ultrasonic inspection method and the directivity in the conventional ultrasonic inspection method.

  Hereinafter, embodiments of an ultrasonic inspection method and a probe installation jig according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment.

[First Embodiment]
The first embodiment will be described with reference to FIGS. This embodiment relates to an ultrasonic inspection method and a probe installation jig 5. In the ultrasonic inspection method, a part that is difficult to visually recognize, such as an embedded object or a shield, for example, as shown in FIG. 1, a pipe P as an inspection object is installed below the bridge beam B1 of the bridge B (pipe P1), This is a method for inspecting the corrosion X in the pipe P2 when it is buried in the ground G through the abutment B2 (the pipe P2). In the pipe P, the pipe P1 installed below the bridge girder B1 is exposed to the outside, so that it is visually confirmed, and the part embedded in the ground G is not subject to the current inspection. Therefore, in this ultrasonic inspection method, the pipe P2, which is difficult to visually recognize in the pipe P, is inspected using the ultrasonic inspection apparatus 1 and the probe installation jig 5.

  The ultrasonic inspection apparatus 1 is attached to the pipe P, transmits the SH guide wave W1, receives the reflected wave W2, and inspects the corrosion X. Specifically, the ultrasonic inspection apparatus 1 is attached to the pipe P1 exposed to the outside, transmits the SH guide wave W1 from the pipe P1 toward the pipe P2, reflects from the corrosion X, and is reflected from the pipe P2. The reflected wave W2 propagating to the pipe P1 is received. As shown in FIGS. 1 and 2, the ultrasonic inspection apparatus 1 mainly includes a first transmission / reception probe 2 and a second transmission / reception probe 3 as a measurement transmission / reception probe, and a reception probe 4. A transmission / reception device 6 and a storage / evaluation PC (PC) 8 are provided.

  As shown in FIG. 1, the first transmission / reception probe 2 is attached to the outer peripheral surface of the pipe P1, transmits the SH guide wave W1 in the axial direction of the pipe P2, and transmits the reflected wave W2 from the pipe P2. A sensor having a vibrator to receive. The first transmission / reception probe 2 is formed in a rectangular parallelepiped box shape. The size of the vibrator is, for example, about several tens mm × several tens mm. Further, the first transmission / reception probe 2 generates a vibration by applying a high-frequency pulse voltage to the vibrator, and generates and transmits an SH guide wave W1. Information on the high-frequency pulse voltage applied to the vibrator is included in the transmission signal for the first transmission / reception probe 2 generated by the transmission / reception device 6 described later. Further, the first transmission / reception probe 2 receives the vibration generated by the vibration of the transducer by converting it into an electric signal. The first transmission / reception probe 2 is controlled by a transmission / reception device 6 described later. The SH guide wave W1 transmitted from the first transmission / reception probe 2 propagates through the peripheral surfaces of the pipes P1 and P2 and is reflected by the corrosion X to become a reflected wave W2. The reflected wave W2 is reflected on the first transmission / reception probe. Child 2 receives.

  Here, the SH guide wave W1 is a non-dispersion mode chirp wave or burst wave. Thus, the SH guide wave W1 transmitted from the first transmission / reception probe 2 propagates in the axial direction through a portion of the pipe P2 in the circumferential direction.

  The second transmission / reception probe 3 is attached to the outer peripheral surface of the pipe P1 in parallel with the first transmission / reception probe 2 and the propagation direction of the SH guide wave W1, that is, in parallel with the axial direction of the pipe P1. That is, the first transmission / reception probe 2 and the second transmission / reception probe 3 are attached at the same position in the axial direction of the pipe P1 and on the outer peripheral surface of the pipe P1 with a gap in the circumferential direction. The second transmission / reception probe 3 is a sensor having a configuration equivalent to that of the first transmission / reception probe 2, and is the same (same frequency, same intensity) as the SH guide wave W1 transmitted by the first transmission / reception probe 2. Control is performed by a transmitter / receiver 6 described later so that the SH guide wave W1 is transmitted simultaneously.

  Here, the first transmission / reception probe 2 and the second transmission / reception probe 3 constitute an “apparent transmission / reception probe”. The first transmission / reception probe 2 and the second transmission / reception probe 3 constituting the apparent transmission / reception probe are arranged in parallel and simultaneously transmit the same SH guide wave W1. For this reason, in the apparent transmission / reception probe, since the two SH guide waves W1 are combined, the SH guide wave W1 output from each of the first transmission / reception probe 2 and the second transmission / reception probe 3 The output level increases compared to the reflected wave W2. Further, the apparent transmission / reception probe has a circumferential width of the pipe P1 between the left end of the first transmission / reception probe 2 in FIG. 5 and the right end of the second transmission / reception probe 3 in FIG. " The apparent width is larger than the width in the circumferential direction of each pipe P1 of the first transmission / reception probe 2 and the second transmission / reception probe 3. For this reason, the directivity of the apparent transmission / reception probe is improved as compared with each of the first transmission / reception probe 2 and the second transmission / reception probe 3.

  When a single transmitter / receiver probe having a wider width is attached to the outer peripheral surface of the pipe P1 without arranging the transmitter / receiver probes in parallel, the single transmitter / receiver probe having a wider width is inspected. There is a possibility that the output level and directivity of the ultrasonic wave may be lowered due to the influence of the outer peripheral surface of the object.

  The reception probe 4 is attached to the pipe P1, and the reference wave W3 (see FIG. 5) is obtained by transmitting the SH guide wave W1 transmitted from the first transmission / reception probe 2 and the second transmission / reception probe 3 through the pipe P1. 6), the sensor having a vibrator to receive. The size of the vibrator is, for example, about several tens mm × several tens mm. The receiving probe 4 receives the vibration generated by the vibration of the vibrator by converting it into an electric signal. The reception probe 4 is controlled by a transmitter / receiver 6 described later.

  The first transmission / reception probe 2, the second transmission / reception probe 3, and the reception probe 4 are supported by a probe installation jig 5 (see FIG. 1). The probe installation jig 5 is used for an ultrasonic inspection method, and detachably installs the first transmission / reception probe 2, the second transmission / reception probe 3, and the reception probe 4 on the pipe P1. is there. As shown in FIGS. 3 and 4, the probe installation jig 5 mainly includes a first support frame 51, a second support frame 52, and a handle 53.

  As shown in FIG. 5, the first support frame 51 supports the first transmission / reception probe 2 and the second transmission / reception probe 3 in parallel and pressed against the pipe P <b> 1. As shown in FIGS. 3 and 4, the first support frame 51 is formed in a box shape that can accommodate the first transmission / reception probe 2 and the second transmission / reception probe 3 (see FIG. 4). As shown in FIG. 5, the first transmission / reception probe 2 and the second transmission / reception probe 3 housed in the first support frame 51 are brought into close contact with the bottom surface portion of the pipe P1. As shown in FIGS. 3 and 4, the first support frame 51 has a connecting arm 512 that connects the opposing side plates 511 to each other. Specifically, as illustrated in FIG. 5, the end portions of the opposing side plates 511 configured by a substantially fan-shaped thin plate are connected by four connecting arms 512. One side (the bottom side in the figure) of the side plate 511 is curved along the outer peripheral surface of the pipe P1.

  A magnet 513 (see FIGS. 3 and 5) is disposed below the lower connection arm 512 (on the pipe P1 side). When the magnet 513 is in close contact with the pipe P1, the first support frame 51 is It adheres in a state where it is pressed against the pipe P1. Thereby, the 1st transmission / reception probe 2 and the 2nd transmission / reception probe 3 accommodated in the 1st support frame 51 are also closely_contact | adhered in the state pressed against the piping P1.

  As shown in FIGS. 3 and 4, the second support frame 52 transmits the reception probe 4 to the propagation direction of the SH guide wave W <b> 1 transmitted from the first transmission / reception probe 2 and the second transmission / reception probe 3. Furthermore, it supports in the state pressed against the piping P1. The second support frame 52 is formed in a box shape that can accommodate the reception probe 4. The receiving probe 4 housed in the second support frame 52 is brought into close contact with the bottom surface portion pressed against the pipe P1. As shown in FIG. 4, the reception probe 4 accommodated in the second support frame 52 is positioned on the center line of the first transmission / reception probe 2 and the second transmission / reception probe 3 by the arm 52A. Supported. As shown in FIG. 3, the arm 52 </ b> A has a second support frame 52 slidably disposed with respect to the first support frame 51.

  More specifically, the arm 52A is slidable with respect to the first support frame 51 by a pin 52a. For this reason, when the arm 52A is slid and the second support frame 52 is lifted, the reception probe 4 accommodated in the second support frame 52 is separated from the pipe P1. Further, the second support frame 52 is slidable with respect to the arm 52A by the pin 52b. Therefore, the inclination of the reception probe 4 accommodated in the second support frame 52 with respect to the pipe P1 can be adjusted.

  Thus, the second support frame 52 is disposed on the first support frame 51 via the arm 52A, and the first transmission / reception probe supported by the first support frame 51 that has received the reflected wave W2 from the pipe P1. The distance between the probe 2 and the second transmission / reception probe 3 and the reception probe 4 supported by the second support frame 52 that has received the reference wave W3 is a predetermined distance.

  A magnet 521 (see FIG. 3) is disposed below the second support frame 52, and the second support frame 52 is in close contact with the pipe P1. Thereby, the receiving probe 4 accommodated in the second support frame 52 is also brought into close contact with the pipe P1 in a pressed state.

  The handle 53 is disposed on the first support frame 51 and facilitates handling during transportation or inspection of the probe installation jig 5.

  When the probe installation jig 5 having such a configuration is attached to the pipe P1, when the side plate 511 is attached in a state of facing the propagation direction of the SH guide wave W1, it is accommodated in the first support frame 51. The first transmission / reception probe 2 and the second transmission / reception probe 3 are arranged in parallel in the propagation direction of the SH guide wave W1.

  The transmission / reception device 6 applies a high-frequency pulse voltage to each transducer of the first transmission / reception probe 2 and the second transmission / reception probe 3 in order to generate chirp waves and burst waves based on preset parameters. In addition, control is performed to generate the SH guide wave W1 by generating vibration. The transmission / reception device 6 controls to receive the vibrations generated by the vibrations of the transducers of the first transmission / reception probe 2, the second transmission / reception probe 3, and the reception probe 4 by converting them into electric signals. The transmission / reception device 6 is connected to the first transmission / reception probe 2 and the second transmission / reception probe 3 by signal lines.

  The PC 8 is a terminal device for storing or evaluating the reflected wave W2 and the reference wave W3. As shown in FIG. 1, the PC 8 is connected to the transmission / reception device 6 via a communication line, and can communicate with each other. As shown in FIG. 2, the PC 8 mainly includes a storage unit 81, a correlation processing unit 82, an evaluation processing unit 83, an image generation processing unit 84, a display unit 85, and a control unit 80 for controlling these. It has.

  The storage unit 81 stores the waveform information of the reflected wave W2 transmitted from the transmission / reception device 6 and the waveform information of the reference wave W3, the program of the correlation processing unit 82, the evaluation processing unit 83, and the image generation processing unit 84, Stores tasks and data necessary for information processing. In addition to the waveform information of the reflected wave W2, the reference wave W3, and the correlation wave W4 (see FIG. 6), the storage unit 81 includes the first transmission / reception probe 2, the second transmission / reception probe 3, and the reception probe at the time of measurement. Measurement condition information including the circumferential position of the pipe P1 of the contact 4 is stored. Furthermore, the storage unit 81 stores pipe information including the pipe diameter, plate thickness, length, and embedment condition of the pipe P.

  The correlation processing unit 82 has a function of improving signal discrimination. More specifically, as shown in FIGS. 6 and 12, the correlation processing unit 82 includes waveform information of the reference wave W3 received by the reception probe 4, the first transmission / reception probe 2, and the second transmission / reception probe. 3 is a program or task having a function of performing correlation processing based on the received waveform information of the reflected wave W2 and calculating the waveform information of the correlated wave W4. For example, the control unit 80 controls the correlation processing unit 82 so as to start at the timing when the measurement processing in step S1 in the flowchart shown in FIG. 7 to be described later ends or at any timing designated by the user. Here, whether or not the measurement process is finished depends on the measurement of the reflected wave W2 by the first transmission / reception probe 2 and the second transmission / reception probe 3 and the measurement of the reference wave W3 by the reception probe 4 on the pipe P1. It is determined by whether or not the process has been completed over the entire circumference.

The correlation processing in the correlation processing unit 82 outputs, as a high value, a signal having a frequency component similar to that of the reference wave W3 in the reflected wave W2. Specifically, when the waveform information of the reference wave W3 is h (t) and the waveform information of the reflected wave W2 is x (t + τ), the waveform information z (τ) of the correlation wave W4 is calculated by the following equation.
z (τ) = ∫h (t) x (t + τ) dt
The waveform information of the correlation wave W4 calculated by the correlation processing unit 82 in this way is stored in the storage unit 81. Further, the waveform information of the correlation wave W4 calculated by the correlation processing unit 82 is obtained by removing noise mixed in the reflected wave W2.

  The evaluation processing unit 83 calculates (1) the position of the corrosion X (axial distance, circumferential position) in the pipe P2 based on the waveform information of the correlation wave W4 calculated by the correlation processing unit 82, (2) A program and a task having a function of performing a process of estimating the corrosion X by estimating the depth of the corrosion X. For example, as shown in FIG. 6, the evaluation processing unit 83 is controlled by the control unit 80 so as to be started following the end of the processing in the correlation processing unit 82.

(1) Calculation of the position of the corrosion X The distance in the axial direction of the pipe P2 of the corrosion X can be calculated based on the difference between the transmission time of the SH guide wave W1 and the reception time of the reflected wave W2. Further, the circumferential position of the corrosion X pipe P2 is calculated based on the circumferential position of the pipe P1 of the first transmission / reception probe 2 and the second transmission / reception probe 3 that have received the reflected wave W2. Specifically, when the corrosion X is located on the center line of the first transmission / reception probe 2 and the second transmission / reception probe 3, the propagation path of the SH guide wave W1 is the shortest, and the calculated axial distance is also It will be the shortest. The farther the corrosion X is from the center line of the first transmission / reception probe 2 and the second transmission / reception probe 3, the longer the propagation path of the SH guide wave W1, and the longer the axial distance to be calculated. For this reason, the circumferential direction of the pipe P2 of corrosion X is compared by comparing a plurality of data with different circumferential positions of the pipe P1 of the first transmission / reception probe 2 and the second transmission / reception probe 3 that have received the reflected wave W2. The position can be calculated. That is, by comparing the transition of the reflected wave W2 according to the circumferential position of the pipe P1 of the first transmission / reception probe 2 and the second transmission / reception probe 3 that have received the reflected wave W2, the corrosion X of the pipe P2 of the corrosion X is compared. A circumferential position can be obtained. In this way, the position of the corrosion X (axial distance, circumferential position) is calculated.

(2) Estimation of depth of corrosion X The depth of corrosion X can be estimated based on the signal intensity of the reflected wave W2. Specifically, evaluation reference data serving as a threshold value for estimating the depth of corrosion X is stored in advance for each tube diameter and plate thickness, and the evaluation reference data and the signal intensity of the received reflected wave W2 are determined. To estimate the depth of the corrosion X. As the evaluation standard data, test pipes having different pipe diameters and plate thicknesses are prepared, and artificial corrosion with different depths is formed in a shape close to the actual shape of the corrosion X. Then, the measurement position is changed on the test pipe, and the waveform information of the reflected wave W2 caused by the artificial corrosion is stored as transition information of the signal value corresponding to the distance. Thus, the depth of the corrosion X is estimated by acquiring data corresponding to the pipe P2 and corresponding to the received reflected wave W2, the measurement position, and the like from the evaluation reference data stored in advance.

  The image generation processing unit 84 is a program or task having a function of performing processing to generate the position and depth of the corrosion X calculated by the evaluation processing unit 83 as an image. For example, as shown in FIG. 6, the image generation processing unit 84 is controlled by the control unit 80 so as to be started following the end of the processing in the evaluation processing unit 83. In this embodiment, data for outputting the images shown in FIGS. 10 and 11 to the display unit 85 is generated. FIG. 10 shows the signal intensity of the waveform information of the correlation wave W4 at each position in contrast, with the vertical axis representing the circumferential position and the horizontal axis representing the axial position. Here, corrosion X can be confirmed at a position indicated by an arrow in the figure. From FIG. 10, it can be confirmed that the closer the circumferential position is to zero, the smaller the axial distance is calculated, and the greater the absolute value of the circumferential position is, the greater the axial distance is calculated.

  FIG. 11 shows the signal intensity of the waveform information of the correlation wave W4 at the axial position, where the vertical axis is the signal value and the horizontal axis is the axial position, and the threshold value of the evaluation reference data is indicated by a curve. ing. Accordingly, the depth of the corrosion X can be estimated depending on which height the signal value shown in FIG. 11 corresponds to the two-stage threshold value. Here, corrosion X can be confirmed at a position indicated by an arrow in the figure. This corrosion X exceeds the higher threshold value, and can be estimated to be a depth of a predetermined value or more.

  The display unit 85 is a display device such as a liquid crystal display that displays the image generated by the image generation processing unit 84.

  The control unit 80 controls the correlation processing unit 82, the evaluation processing unit 83, and the image generation processing unit 84 to be activated in the order shown in FIG.

  The ultrasonic inspection apparatus 1 and the probe installation jig 5 according to this embodiment are configured as described above. Hereinafter, an ultrasonic inspection method using these and an operation thereof will be described. In this embodiment, as shown in FIG. 1, when the pipe P is installed below the bridge beam B1 of the bridge B (pipe P1) and penetrates the abutment B2 (pipe P2), the pipe P as an inspection target. The case of inspecting corrosion X will be described. In this embodiment, as shown in FIG. 7, first, using the ultrasonic inspection apparatus 1 and the probe installation jig 5, the SH guide wave W1 is transmitted, and the reflected wave W2 and the reference wave W3 are measured. (Step S1), and thereafter, evaluation is performed based on the stored reflected wave W2 and reference wave W3 (Step S2).

  First, the installation position of the ultrasonic inspection apparatus 1 is marked on the outer peripheral surface of the pipe P1 on the pipe P2 side. This crease line can be measured over the entire circumference of the pipe P1 in the circumferential direction so that it can be measured over the entire circumference of the pipe P1 when the ultrasonic inspection apparatus 1 is repeatedly arranged and measured on each crease line. To divide.

  Next, the SH guide wave W1 is transmitted and the reflected wave W2 and the reference wave W3 are measured according to step S1 shown in FIG. 7, that is, a flowchart showing the measurement processing procedure of the ultrasonic inspection method shown in FIG. Processing will be described. First, the ultrasonic inspection apparatus 1 is installed on the ruled line of the pipe P1 by the operator (step S11). At this time, the side plate 511 of the first support frame 51 is disposed in a state along the circumferential direction of the pipe P1, that is, the side plate 511 is disposed in a state of facing the propagation direction of the SH guide wave W1. Further, the first transmission / reception probe 2 and the second transmission / reception probe 3 supported by the first support frame 51 are pressed against the pipe P1 by the magnet 513 and the magnet 521 and are in close contact with each other. Further, the second support frame 52 is slid and lifted with respect to the first support frame 51, and the reception probe 4 accommodated in the second support frame 52 is separated from the pipe P1. ing.

  Then, the SH guide wave W1 is transmitted by the first transmission / reception probe 2 and the second transmission / reception probe 3 of the ultrasonic inspection apparatus 1 (step S12), and the first transmission / reception probe 2 and the second transmission / reception probe. The reflected wave W2 is received by the child 3 (step S13). The waveform information of the reflected wave W2 received by the first transmission / reception probe 2 and the second transmission / reception probe 3 is digitized by the transmission / reception device 6, and the first transmission / reception probe 2 and the second transmission / reception probe. Measurement information including the circumferential position of the three pipes P1 is stored in the storage unit 81 by the control unit 80 of the PC 8.

  Then, the operator lowers the second support frame 52 until the reception probe 4 comes into close contact with the pipe P1 (step S14). Then, the reference wave W3 is received by the reception probe 4 of the ultrasonic inspection apparatus 1 (step S15). The waveform information of the reference wave W3 received by the reception probe 4 is digitized by the transmission / reception device 6 and stored in the storage unit 81 by the control unit 80 of the PC 8 together with the circumferential position of the pipe P1 of the reception probe 4. Remembered.

  Then, it is confirmed by the operator whether or not the measurement at all positions on the ruled line of the pipe P1 has been completed (step S16). If the measurement has not been completed (in the case of “No”), the operator As a result, the handle 53 of the probe installation jig 5 is gripped, and the probe installation jig 5 is removed from the pipe P1 and moved onto the adjacent ruled line (step S17). Then, the processing of steps S11 to S16 is repeated, and the measurement information of the reflected wave W2 and the waveform information of the reference wave W3 are stored in the storage unit 81 by the control unit 80 of the PC 8. Such processing is repeated until measurement at all positions on the ruled line of the pipe P1 is completed (until “Yes” is determined in step S16).

  In this manner, when the probe installation jig 5 moves in the circumferential direction of the pipe P1 and the process of measuring the reflected wave W2 and the reference wave W3 is repeated, the ultrasonic inspection apparatus is provided over the entire circumference of the pipe P2. 1, the reflected wave W 2 and the reference wave W 3 are measured, and the measurement information of the reflected wave W 2 and the waveform information of the reference wave W 3 are stored in the storage unit 81 by the control unit 80 of the PC 8.

  Subsequently, evaluation is performed based on the stored measurement information of the reflected wave W2 and the waveform information of the reference wave W3 in accordance with step S2 shown in FIG. 7, that is, the flowchart showing the evaluation processing procedure of the ultrasonic inspection method of FIG. The process of performing will be described. First, based on the measurement information of the reflected wave W2 and the waveform information of the reference wave W3 stored in the storage unit 81 of the PC 8 by the correlation processing unit 82 of the ultrasonic inspection apparatus 1, the reference wave W3 in the reflected wave W2 is displayed. Is output as a high value, and the waveform information of the correlation wave W4 is output (step S21). Then, based on the waveform information of the correlation wave W4 output from the correlation processing unit 82, the evaluation processing unit 83 calculates the position of the corrosion X and the depth of the corrosion X from the signal intensity (step S22). Then, the image generation processing unit 84 generates an image based on the position and depth of the corrosion X calculated by the evaluation processing unit 83 (step S23), and displays the image shown in FIG. 10 and FIG. 11 on the display unit 85. Is output (step S24).

  Then, the operator confirms the images of FIG. 10 and FIG. 11 displayed on the display unit 85 of the PC 8, and confirms the presence / absence of the corrosion X, the position, and the depth over the entire circumference of the pipe P2.

  With the above ultrasonic inspection method, the reference wave W3 received by the receiving probe 4 is transmitted by transmitting the SH guide wave W1 toward the pipe P2 using the ultrasonic inspection apparatus 1 and the probe installation jig 5. The correlation processing unit 82 performs correlation processing based on the reflected wave W2 received by the first transmission / reception probe 2 and the second transmission / reception probe 3. Thereby, since the correlation process is performed based on the reference wave W3 actually propagated through the pipe P2 and received by the reception probe 4, the accuracy of consistency in the correlation process is improved, the signal discrimination is improved, and the inspection accuracy is improved. Can be further improved.

  In the ultrasonic inspection apparatus 1, the first transmission / reception probe 2 and the second transmission / reception probe 3 are arranged in parallel in the propagation direction of the SH guide wave W1. For this reason, in the apparent transmission / reception probe described above, the two SH guide waves W1 are combined, so the SH guide waves output from the first transmission / reception probe 2 and the second transmission / reception probe 3, respectively. The output level can be increased compared to W1 and the reflected wave W2. Further, the apparent transmission / reception probe can improve the directivity as compared with each of the first transmission / reception probe 2 and the second transmission / reception probe 3. As a result, the ultrasonic inspection apparatus 1 has an increased output level and improved directivity compared to the SH guide wave W1 and the reflected wave W2, so that the inspection accuracy can be further improved.

  Here, the ultrasonic inspection method using the ultrasonic inspection apparatus 1 and the probe installation jig 5 (hereinafter, “ultrasonic inspection method according to this embodiment”) and the conventional ultrasonic inspection apparatus 10 are used. In order to compare the effect with the conventional ultrasonic inspection method (hereinafter referred to as “conventional ultrasonic inspection method”), an ultrasonic inspection apparatus using the same specimen Q shown in FIG. 1 and an ultrasonic inspection using the probe installation jig 5 were performed. Specifically, 200 A of SGP (carbon steel pipe for piping) is used as the test body Q. In the test body Q, a simulated corrosion X1 is formed on the outer peripheral surface. The simulated corrosion X1 has two mortar-shaped grooves having a diameter of 5 mm and a depth (1.9 mm) of one third of the thickness (5.8 mm) of the test specimen Q in the axial direction of the test specimen Q. Four are formed adjacent to each other in the direction. The first transmission / reception probe 2 and the second transmission / reception probe 3 of the ultrasonic inspection apparatus 1 or the transmission / reception probe of the conventional ultrasonic inspection apparatus 10 are arranged 1000 mm apart from the simulated corrosion X1 in the axial direction. . The conventional ultrasonic inspection apparatus 10 measures a reflected wave using one transmission / reception probe having the same configuration as the first transmission / reception probe 2 and the second transmission / reception probe 3. The conventional ultrasonic inspection apparatus 10 does not include the reception probe 4, the probe installation jig 5, and the PC 8 of the ultrasonic inspection apparatus 1.

  FIG. 14 is a diagram for explaining signal discrimination in the conventional ultrasonic inspection method, and FIG. 15 is a diagram for explaining signal discrimination in the ultrasonic inspection method according to this embodiment. In FIG. 15, the ratio of the signal value indicating the simulated corrosion X1 to the noise level is about 10, and the difference from the noise level is clear. On the other hand, in FIG. 14, the ratio of the signal value indicating the simulated corrosion X1 to the noise level is about 2, and the difference from the noise level is small. Accordingly, it can be confirmed that the signal discrimination of the simulated corrosion X1 is improved in the ultrasonic inspection method according to this embodiment as compared with the conventional ultrasonic inspection method. This is because, in the ultrasonic inspection method according to this embodiment, the first transmission / reception probe 2 and the second transmission / reception probe 3 are arranged in parallel. This is because the output level of the wave W2 has increased and the signal value has increased. Further, in the ultrasonic inspection method according to this embodiment, the correlation wave W4 in which the noise level of the reflected wave W2 is reduced is obtained by the correlation processing in the correlation processing unit 82.

  FIG. 16 is a diagram for explaining the directivity in the ultrasonic inspection method according to this embodiment and the directivity in the conventional ultrasonic inspection method. This is because the test body Q is used to correct the first transmission / reception probe 2 and the second transmission / reception probe 3 of the ultrasonic inspection apparatus 1 or the transmission / reception probe of the conventional ultrasonic inspection apparatus 10 as simulated corrosion X1. It shows the transition of the signal value indicating the simulated corrosion X1 when measurement is performed by shifting the position (circumferential position (position in the circumferential direction) 0 mm) from the position (circumferential position (circumferential position) 0 mm) by about 50 mm in the circumferential direction. According to the ultrasonic inspection method according to this embodiment, the first transmission / reception probe 2 and the second transmission / reception probe 3 are separated from the position facing the simulated corrosion X1 (as the absolute value of the circumferential position increases). The signal value indicating the simulated corrosion X1 is reduced. More specifically, the signal value indicating the simulated corrosion X1 has a maximum value at about 72 mV when the circumferential position is 0 mm, and has a minimum value at about 19 mV when the circumferential position is −150 mm (about 21 mV when the circumferential position is 150 mm). . On the other hand, according to the conventional ultrasonic inspection method, the signal value indicating the simulated corrosion X1 has a maximum value of about 24 mV when the circumferential position is 0 mm, and about 11 mV when the circumferential position is 150 mm (the circumferential position is −150 mm). In this case, the minimum value is about 14 mV) and the difference between the maximum value and the minimum value is small. Thereby, compared with the conventional ultrasonic inspection method, in the ultrasonic inspection method according to this embodiment, it can be confirmed that the difference in signal value depending on the circumferential position is clear and the directivity is improved. This is because, in the ultrasonic inspection method according to this embodiment, the directivity of the apparent transmission / reception probe described above is improved compared to the first transmission / reception probe 2 and the second transmission / reception probe 3. It is.

  Further, the first transmission / reception probe 2, the second transmission / reception probe 3, and the reception probe 4 are detachably installed on the pipe P1 by the probe installation jig 5, and the reflected wave from the pipe P2 is provided. The distance between the first transmission / reception probe 2 and the second transmission / reception probe 3 that have received W2 and the reception probe 4 supported by the second support frame 52 that has received the SH guide wave W1 as the reference wave W3 is as follows: It is a predetermined distance. For this reason, in the ultrasonic inspection method, the first transmission / reception probe 2, the second transmission / reception probe 3, and the reception probe 4 can be easily attached to and detached from the pipe P1. For this reason, labor and time required for the inspection can be reduced.

[Second Embodiment]
The ultrasonic inspection method according to the second embodiment is different from the first embodiment in that the reference wave W3 is measured in advance by a test pipe using the ultrasonic inspection apparatus 1 and the probe installation jig 5. Different. In addition, with respect to configurations, operations, and effects that are common to the above-described embodiments, redundant description is omitted as much as possible, and for a schematic configuration, refer to FIG. 1 and the like as appropriate. The same or corresponding reference numerals are assigned to components that are common to and correspond to those of the above-described embodiments.

  First, a test pipe that is made of the same material as the pipe P to be inspected and has the same pipe diameter, plate thickness, and length and is installed in the same environment as the pipe P is prepared. The operator marks the test pipe in the same manner as the pipe P. Then, the first transmission / reception probe 2, the second transmission / reception probe 3, and the reception probe 4 are installed in the test pipe via the probe installation jig 5. Then, the operator moves the probe installation jig 5 in the circumferential direction of the test pipe, repeats the process of measuring only the reference wave W3 by the ultrasonic inspection apparatus 1, and makes the entire circumference of the test pipe. The reference wave W3 is measured over a period of time, and the waveform information of the reference wave W3 is stored in the storage unit 81 by the control unit 80 of the PC 8. Further, the reference wave W3 under different measurement conditions is measured by changing the temperature and humidity, and stored as prior measurement data.

  Then, at the site where the measurement is performed, the operator moves the probe installation jig 5 in the circumferential direction of the pipe P1 and repeats the process of measuring only the reflected wave W2 by the ultrasonic inspection apparatus 1, thereby The reflected wave W2 is measured over the entire circumference of P2, and the measurement information of the reflected wave W2 is stored in the storage unit 81 by the control unit 80 of the PC 8.

  And the pre-measurement data of the reference wave W3 corresponding to measurement conditions, such as temperature at the time of field work, humidity, etc. are acquired from the memory | storage part 81, and based on the stored pre-measurement data of the reflected wave W2 and the acquired reference wave W3 To evaluate (step S2 shown in FIG. 7).

  In the ultrasonic inspection method described above, since the reference wave W3 is measured in advance using test pipes and stored in advance as measurement data, only the reflected wave W2 needs to be measured during field work. For this reason, the field work in the piping P can be reduced.

  The ultrasonic inspection method and the probe installation jig 5 according to the above-described embodiment of the present invention are not limited to the above-described embodiment, and various modifications are possible within the scope described in the claims. is there. The ultrasonic inspection method and the probe installation jig 5 according to this embodiment may be configured by appropriately combining the components of the embodiments and modifications described above.

  For example, the PC 8 may be configured as an information processing apparatus such as a known personal computer or workstation, or may be configured by connecting an arbitrary peripheral device to the information processing apparatus. Further, the PC 8 may be realized by installing software (including programs, data, and the like) that causes the information processing apparatus to realize the method of the present invention.

  The PC 8 and the transmission / reception device 6 are connected via a communication line, but may be capable of communicating with each other via wireless communication.

  Furthermore, a slide mechanism such as a rail that makes the probe installation jig 5 slidable along the circumferential direction of the pipe P may be provided.

DESCRIPTION OF SYMBOLS 1 Ultrasonic inspection apparatus 2 1st transmission / reception probe (transmission / reception probe for measurement)
3 Second transmitter / receiver probe (transmission / reception probe for measurement)
4 Reception Probe 5 Probe Installation Jig 51 First Support Frame 52 Second Support Frame 53 Handle 6 Transmitter / Receiver 8 PC
81 Storage Unit 82 Correlation Processing Unit 83 Evaluation Processing Unit 84 Image Generation Processing Unit 85 Display Unit W1 SH Guide Wave W2 Reflected Wave W3 Reference Wave W4 Correlation Wave B Bridge B1 Bridge Girder B2 Abutment P Piping (Inspection Object)
P1 piping P2 piping X Corrosion

Claims (6)

An SH guide wave transmitting step of transmitting an SH guide wave toward the inspection object by the measurement transmission / reception probe;
A reference wave receiving step of receiving, as a reference waveform, the SH guide wave transmitted from the transmission / reception probe for measurement by a reception probe;
A reflected wave receiving step of receiving a reflected wave from the inspection object by the measurement transmission / reception probe;
A correlation processing step for performing correlation processing based on the reference waveform received by the reception probe and the reflected wave received by the transmission / reception probe for measurement;
An output step of outputting a correlation waveform obtained by the correlation processing step;
An ultrasonic inspection method comprising: A plurality of the transmission / reception probes for measurement are arranged in parallel in the propagation direction of the SH guide wave.
The ultrasonic inspection method according to claim 1. A moving step of moving the transmission / reception probe for measurement and the reception probe in a direction different from a propagation direction of the SH guide wave to be inspected;
With
The inspection object is piping,
The propagation direction of the SH guide wave coincides with the axial direction of the pipe,
After performing the SH guide wave transmitting step, the reference wave receiving step, and the reflected wave receiving step at a predetermined location on the outer peripheral surface of the inspection target, the moving step is performed to perform the outer peripheral surface of the inspection target. Is repeatedly moved in the circumferential direction, and the inspection object is inspected over the entire circumference.
The ultrasonic inspection method according to claim 1 or 2. A probe installation jig used in the ultrasonic inspection method according to any one of claims 1 to 3, wherein the transmission / reception probe for measurement and the reception probe are detachably installed on the inspection target. Because
A first support frame for supporting the measurement transmission / reception probe in a state of being pressed against the inspection target;
A second support frame for supporting the reception probe in a state in which the reception probe is pressed against the inspection target in the propagation direction of the SH guide wave transmitted from the measurement transmission / reception probe;
With
The second support frame is disposed on the first support frame, and the transmission / reception probe for measurement supported by the first support frame that has received the reflected wave from the inspection object, and the SH guide wave. The distance from the reception probe supported by the second support frame received as a reference waveform is a predetermined distance.
A probe installation jig characterized by that. The first support frame supports a plurality of the transmission / reception probes for measurement in parallel in the propagation direction of the SH guide wave,
The second support frame supports the reception probe while being positioned on a center line of the plurality of transmission / reception probes for measurement,
The probe installation jig according to claim 4, wherein: The second support frame is slidably disposed with respect to the first support frame;
The probe installation jig according to claim 4 or 5, characterized in that

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