JP6124191B1 - Corrosion evaluation method - Google Patents

Abstract

The present invention provides a corroded portion evaluation method capable of identifying only a corrugated portion reflected by a corroded portion and evaluating the corrugated portion. When a transmitter 2 is moved on the surface of a metal tube 60 to change the distance between the corroded portion 5 and the transmitter 2, only the waveform portion A of the ultrasonic wave reflected by the corroded portion 5 is along the X axis. Since only the intensity of the noise waveform portion B included in the received wave changes in the vertical direction along the Y axis, the waveform portion A of the longitudinal wave surface wave reflected by the corroded portion 5 and noise The waveform portion B can be separated and the waveform portion A can be evaluated in detail. [Selection] Figure 2

Description

  The present invention relates to a corroded portion evaluation method for evaluating a corroded portion included in a metal member using ultrasonic waves.

  Conventionally, a method for identifying a corroded portion contained in a metal member using ultrasonic waves is well known. For example, Patent Document 1 discloses a configuration for evaluating defects of a metal cylinder using SH waves. Patent Document 2 discloses a configuration for investigating a strut road surface boundary using an SH wave or an SV wave. Both are methods for evaluation based on echoes of corroded portions.

JP 2004-361321 A Utility Model Registration No. 3198840

  However, the waveform diagram of the received wave displayed on the display unit contains noise, and since no method for removing the noise has been established, the waveform diagram is currently evaluated in a state including noise. is there. For this reason, there is a limit to improving the evaluation accuracy, and it is desired that a method capable of solving such a problem is proposed. For example, Patent Documents 1 and 2 do not disclose a method for dealing with such a problem.

  Accordingly, an object of the present invention is to provide a corroded portion evaluation method that can specify only a waveform portion reflected by a corroded portion and evaluate it in a waveform diagram of a received wave displayed on a display portion.

The present invention is a two-probe using a transmitter and a receiver , and transmits ultrasonic waves from a transmitter disposed on the surface of the metal member in order to evaluate a corroded part included in the metal member as a pillar. Then, the ultrasonic wave reflected by the corroded part is received by a receiving part arranged on the surface of the metal member, and a waveform diagram of the received wave is received by a predetermined echo display part with a time axis and the intensity of the received wave. The corrosion part evaluation method for displaying based on the intensity axis indicating the reception, with the passage of time, while changing the separation distance between at least one of the transmission part and the reception part and the corrosion part A change in the waveform diagram of the wave is dynamically displayed on the echo display unit, and the received wave is changed while changing a separation distance between at least one of the transmission unit and the reception unit and the corrosion unit. In the waveform diagram of And moving only the waveform portion of the ultrasonic wave along the time axis, and changing only the intensity of the noise waveform portion received by the receiving unit in a manner in which the intensity increases or decreases in a predetermined cycle along the intensity axis. Then, by displaying the change mode, the waveform portion of the ultrasonic wave reflected from the corrosion portion and the noise waveform portion are separated, and the echo display portion has the time axis as a horizontal axis, The intensity axis is a vertical axis, and the ultrasonic wave is a longitudinal surface wave of 1 MHz or less, and the waveform diagram is an AC wave having both a positive wave part and a negative wave part that are not rectified of the received wave. It is a corroded part evaluation method characterized by being a waveform diagram .

  Here, in the configuration described above, the reflected wave is reflected by the corroded portion in the waveform diagram of the received wave while changing the distance between at least one of the transmitting portion and the receiving portion and the corroded portion. Only the waveform portion of the ultrasonic wave can be moved along the time axis.

  In this way, only the waveform portion of the ultrasonic wave reflected by the corroded portion moves along the time axis, so that the waveform reflected from the corroded portion can be obtained from the waveform diagram including both the waveform portion to be evaluated and the noise portion. Only the waveform portion of the sound wave can be separated and the waveform portion can be evaluated in detail.

  Further, in the above configuration, the noise waveform portion received by the receiving unit in the waveform diagram of the received wave is changed while changing the separation distance between at least one of the transmitting unit and the receiving unit and the corroded unit. Only the intensity can be varied along the intensity axis.

  In this way, only the intensity of the noise waveform portion received by the receiving unit changes along the intensity axis, so that a waveform diagram that includes both the waveform portion to be evaluated and the noise portion is reflected from the corroded portion. Only the waveform portion of the sound wave can be separated and the waveform portion can be evaluated in detail.

  In the echo display unit, it is desirable that the time axis is a horizontal axis and the intensity axis is a vertical axis.

  With this configuration, it is possible to display the waveform diagram of the received wave, for example, with XY coordinates.

  Moreover, it is desirable that the ultrasonic wave is a longitudinal surface wave of 1 MHz or less.

  With such a configuration, it is possible to reduce noise caused by restraint.

  Since the corroded part evaluation method of the present invention can separate and discriminate the noise part of the received wave from the waveform part of the ultrasonic wave reflected from the corroded part, it is possible to evaluate the corroded part with high accuracy.

It is explanatory drawing which shows an evaluation apparatus. It is explanatory drawing which shows an echo display part.

  The case where the corroded portion evaluation method of the present invention is applied to a metal tube (metal member) 60 such as a signal column, a marker column, or an illumination column will be described with reference to the accompanying drawings. In the following description, for the sake of convenience, there may be cases where the front / rear / left / right and up / down directions are defined, which indicates that the present invention is limited to the directions described in the following description. It is not a thing.

  As shown in FIG. 1, the evaluation device 1 used for detecting the corroded portion 5 included in the metal tube 60 includes a transmitter 2 that transmits a longitudinal surface wave (ultrasonic wave) of 1 MHz or less, A receiving unit 3 as a sensor for receiving ultrasonic waves and a waveform display device 4 including an echo display unit 41 shown in FIG. 2 for displaying a waveform diagram of the received received wave are provided.

  As shown in FIG. 2, the echo display unit 41 uses the X axis (horizontal axis) as the time axis and the Y axis (vertical axis) as the intensity axis indicating the intensity of the received wave. Is displayed in two dimensions. The echo display unit 41 can display the received waveform diagram as a moving image, and can dynamically grasp a change in the waveform with time.

Next, a procedure for detecting the corroded portion 5 included in the metal pipe 60 will be described.
First, the transmitter 2 and the receiver 3 are disposed at a required portion of the surface of the metal tube 60. And the longitudinal wave surface wave is transmitted from the transmission part 2, the reception wave is received by the reception part 3, and the position of the corrosion part 5 is specified using the reflected wave. The waveform diagram of the received wave received at this time can be confirmed on the echo display unit 41 (see FIG. 2A).

  Here, when the receiving unit 3 is moved on the surface of the metal tube 60 to change the separation distance between the corroded unit 5 and the receiving unit 3, as shown in FIGS. 2B and 2C in the waveform diagram of the received wave. Only the waveform portion A of the ultrasonic wave reflected by the corroded portion 5 moves in the left-right direction along the X axis. Specifically, when the receiving unit 3 is brought close to the corroded unit 5, the waveform portion A moves to the left as shown in FIG. On the other hand, when the receiving unit 3 is moved away from the corroded unit 5, the waveform portion A moves to the right as shown in FIG.

  Further, when the receiving unit 3 is moved on the surface of the metal tube 60 to change the separation distance between the corroded unit 5 and the receiving unit 3, only the intensity of the noise waveform portion B included in the received wave is vertically changed along the Y axis. To change. Specifically, when the receiving unit 3 is moved closer to or away from the corroded unit 5, the intensity of the waveform portion B increases or decreases at a predetermined cycle, as shown in FIGS.

  Thus, only the waveform portion A of the ultrasonic wave reflected by the corroded portion 5 moves along the X axis, so that the waveform portion A of the longitudinal surface wave reflected by the corroded portion 5 and the noise waveform portion B are obtained. It is possible to separate and evaluate the waveform portion A quantitatively.

  Similarly, only the intensity of the noise waveform portion B of the received wave received by the receiver 3 changes along the Y axis, so that the longitudinal wave surface wave waveform portion A reflected by the corroded portion 5 and the noise waveform Part B can be separated and the waveform part A can be evaluated quantitatively.

  Note that the echo display unit 41 does not necessarily have a moving image display function, and has a function of dynamically grasping a change mode of a waveform diagram of a received wave with a lapse of time at a predetermined time interval. It only has to be. On the other hand, the present invention is different from a technique for evaluating a received wave by a waveform diagram based on a still image.

  Further, the distance from the corroded portion 5 may be changed by changing the position of the transmitting portion 2 instead of the receiving portion 3. Moreover, you may make it change the said separation distance by changing the position of both the transmission part 2 and the receiving part 3. FIG.

  The reason for using the longitudinal wave is as follows. First, there are few restraint noises. Secondly, since the sound speed is the fastest, even if there is a mode conversion due to reflection or the like and it changes to a transverse wave, it can be identified by looking at the fastest reflected wave. Third, there is little change in echo height and it is stable. For example, there is an advantage that there is little change in the echo height regardless of variations in how the sensor is pressed against the measurement surface. Therefore, the echo height is stable even if the sensor is moved. Specifically, the height error is generally ± 2 dB (about 1.3 to 0.8 times), and the echo can be observed while moving the sensor.

  Further, as an advantage of the range of the transmission frequency (1 MHz), firstly, noise can be reduced, and secondly, reflection directivity can be reduced.

  Also, as described above, the advantage of using the so-called two probes is that, first, there is no influence of the transmission pulse, and second, the position where the echo returns most often is not necessarily the transmission position. It is possible to cope with the case where the directionality is unknown, and it is possible to perform flaw detection from multiple directions.

  Moreover, the said Example makes the measurement support | pillar transmission pulse the reference | standard of echo height. Advantages include firstly not being affected by the surface condition, secondly being not affected by temperature changes because of the same point, and thirdly not being affected by curved surfaces. The above configuration is most suitable for sensitivity adjustment.

  In the above configuration, the echo height of the ultrasonic wave is an object to be evaluated, but the height is only a ratio, and “high” or “low” is evaluated with respect to a predetermined echo height (reference). desirable. In general, a so-called bottom surface echo or a reference scratch (standard test piece) can be used as a reference, but in this embodiment, the bottom surface echo often does not appear, and the effect of the surface condition, temperature, or curvature is the reference scratch. May be too large to make sensitivity correction very difficult. Therefore, by adopting the transmitted wave, the disadvantages in the case of the reference flaw can be solved if measurement is performed individually. In addition, since the surface of the corroded part 5 generally has unevenness and is represented by a plurality of reflected waves, it can be evaluated in consideration of not only the echo height but also the area.

2 Transmitter 3 Receiver 5 Corrosion 41 Echo Display 60 Metal Tube (Metal Member)

Claims (1)

In order to evaluate the corroded part included in the metal member that is a pillar, the ultrasonic wave is transmitted from the transmitter disposed on the surface of the metal member with the two probes using the transmitter and the receiver. The ultrasonic wave reflected by the part is received by the receiving part arranged on the surface of the metal member, and a waveform diagram of the received received wave is displayed on the predetermined echo display part on the time axis and the intensity axis indicating the intensity of the received wave. Corrosion part evaluation method to display based on
Those wherein while transmitting unit and the at least one of said receiving portion to change the distance between the corrosion portion, dynamically displaying the change in the waveform diagram of the received wave with time in the echo display unit And
While changing the separation distance between at least one of the transmitter and the receiver and the corroded portion, in the waveform diagram of the received wave, only the waveform portion of the ultrasonic wave reflected by the corroded portion is the time axis. And move along
Only the intensity of the noise waveform portion received by the receiving unit is changed in a mode in which the intensity increases or decreases in a predetermined cycle along the intensity axis, and the change mode is displayed, thereby super Separate the waveform portion of the sound wave from the noise waveform portion,
In the echo display unit, the time axis is a horizontal axis, the intensity axis is a vertical axis,
The ultrasonic wave is a longitudinal surface wave of 1 MHz or less,
The corroded portion evaluation method , wherein the waveform diagram is a waveform diagram of an AC wave having both a positive wave portion and a negative wave portion, in which the received wave is not rectified .

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