JP2013231681A - Non-destructive test device and non-destructive test method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-destructive test device and a non-destructive test method capable of efficiently testing a weld part of piping.SOLUTION: The non-destructive test device includes a non-contact type ultrasonic sensor, a moving mechanism, and a data processing system. The non-contact type ultrasonic sensor is arranged away from a surface of a part welded along a circumferential direction of the piping, and receives transmission waves for which ultrasonic waves transmitted to the surface are transmitted through the inside of the piping. The moving mechanism moves the ultrasonic sensor while measuring a moving position in the circumferential direction of the piping. The data processing system outputs the transmission waves obtained by the non-contact type ultrasonic sensor and position data of the circumferential direction of the piping measured by the moving mechanism.

Description

  Embodiments described herein relate generally to a nondestructive inspection apparatus and a nondestructive inspection method for inspecting a welded portion of a pipe.

  In construction sites where metal pipes are handled in large quantities, there is an urgent need for improvement because of the long waiting time for inspection of welded parts of pipes.

  For example, VT (appearance inspection), PT (penetration inspection), MT (magnetic particle inspection), UT (ultrasonic inspection), RT (radiation transmission test) can be used for nondestructive inspection of welded parts of metal pipes. Etc.

  Among these, UT (ultrasonic flaw detection test) includes three flaw detection inspection methods (pulse reflection method, transmission method, resonance method) and four reflection methods (vertical flaw detection method, oblique flaw detection method, surface wave flaw detection method, plate) There are wave flaw detection methods), but these are methods that are performed after the probe is brought into contact with the pipe.

  For example, at construction sites such as plant facilities and renovation sites, metal pipes of a predetermined length are connected and used by welding.

  However, since the welded portion where the pipes are connected is at a high temperature, it is necessary to wait about half a day until the welded portion is cooled in order to inspect with the above technique.

  In addition, it is necessary to apply a solvent such as oil or jelly to the surface of the piping that contacts the probe so that the probe is brought into close contact with the contact surface so that stable data can be collected. I need it.

JP 2009-271004 A

  In the case of conventional non-destructive inspection, since the probe is brought into direct contact with the part to be inspected, in order to inspect a part that becomes hot like the welded part of the pipe, a waiting time until cooling is required. In addition, the inspection also requires additional work such as solvent application, which is not efficient.

  The problem to be solved by the present invention is to provide a nondestructive inspection apparatus and a nondestructive inspection method capable of efficiently inspecting a welded portion of a pipe.

  The nondestructive inspection apparatus of the embodiment includes a non-contact ultrasonic sensor, a moving mechanism, and a data processing system. The non-contact type ultrasonic sensor is disposed away from the surface of the welded portion along the circumferential direction of the pipe, and the transmitted ultrasonic wave transmitted to the surface transmits the transmitted wave transmitted through the pipe. Receive. The moving mechanism moves the non-contact ultrasonic sensor while measuring a moving position in a circumferential direction of the pipe. The data processing system outputs the transmitted wave obtained by the ultrasonic sensor and the position data in the circumferential direction of the pipe measured by the moving mechanism.

It is a figure which shows the structure of the nondestructive inspection apparatus of embodiment. It is a figure which shows the structure of a nondestructive inspection apparatus. It is a figure which shows the principle of an ultrasonic flaw detection test. It is a figure which shows the reflective echo when a crack etc. do not exist in a welding site | part. It is a figure which shows the reflective echo when a crack etc. exist in a welding site | part.

Hereinafter, embodiments will be described in detail with reference to the drawings.
(First Embodiment) FIG. 1 is a diagram showing a configuration of a nondestructive inspection apparatus according to an embodiment.

  As shown in FIGS. 1 and 2, the nondestructive inspection apparatus of this embodiment includes a non-contact type ultrasonic sensor 1, a moving mechanism 10, and a data processing system 2.

  The moving mechanism 10 includes a rail 20 with a hole fixed along a circumferential direction of a metal pipe 21 as a test body, a carriage unit 17 that moves while being guided by the rail with a hole, and a non-contact ultrasonic wave. It has a stay 15 for supporting the probes 13 and 14 of the sensor 1 and is provided so as to move on the rail 20 with a hole. For example, 210 holes (pitch of about 4 mm) were provided on the entire circumference of the welded portion of the rail 20 with holes.

  The cart unit 17 is provided with a rotary encoder 11. The rotary encoder 11 counts the distance traveled by the carriage unit 17 in the moving direction P around the pipe from the initial position by rotating through the holes of the rail 20 with holes while the teeth of the gears 12 and 16 are engaged. An auxiliary cart 18 for assisting the movement of the cart unit 17 is connected to the rear portion of the cart unit 17. The carriage unit 17 and the auxiliary carriage 18 are provided with wheels 17a and 18a for movement.

  That is, the moving mechanism 10 moves the non-contact ultrasonic sensor 1 from the starting point while measuring the distance moved in the moving direction P around the pipe 21. By measuring the distance from the starting point, the circumferential position on the surface of the pipe 21 can be specified.

  The pipe 21 is a pipe steel pipe using, for example, austenitic stainless steel. In this example, a pipe having a diameter of 250 A × Sch80 and a wall thickness of 15.1 mm (about 20 mm) is used.

  The rail 20 with a hole is arranged at a position spaced apart from the part X welded along the circumferential direction of the pipe 21 (hereinafter referred to as “welded part X”) by a certain distance in the longitudinal direction of the pipe 21.

  The non-contact type ultrasonic sensor 1 is placed on the moving mechanism 10. The non-contact type ultrasonic sensor 1 has two probes 13 and 14. A probe 13a as a first probe for transmission is provided at the tip of the probe 13. At the tip of the probe 14, a probe 14a as a second probe for reception is provided. The probe 13 a and the probe 14 a are arranged apart from the surface of the pipe 21.

  The probe 13a generates (transmits) ultrasonic waves (pulse waves). The probe 14 a receives a transmitted wave in which the ultrasonic wave generated (transmitted) by the probe 13 a has passed through the inner layer of the pipe 21. The probes 13 and 14 are arranged substantially parallel to the surface of the pipe 21 at a predetermined inclination angle θ. In the example of FIG. 3, for example, the inclination angle θ is set to 7 ° to 9 ° with respect to a line segment orthogonal to the surface of the pipe 21.

  That is, it can be said that the ultrasonic wave transmission direction of the probe 13 a and the transmission wave reception direction of the probe 14 a are substantially parallel and inclined with respect to the surface of the pipe 21.

  The pipe 21 is provided with a welded portion X welded to connect the pipes 21 together. The welding range 32 is about 2 cm before and after the center position of the welding site X (welding center position 31).

  The probe 14a of the non-contact ultrasonic sensor 1 is located at a position separated from the welding center position 31 by a predetermined distance 33 (for example, about 10 cm) in the longitudinal direction of the pipe 21 (left side in the drawing). The devices of the moving mechanism 10 including the rail 20 with a hole and the carriage unit 17 are set so as to be spaced apart from each other. That is, the two probes 13a and 14a are not arranged with the welded part X interposed therebetween, but the ultrasonic wave transmission / reception directions are obliquely parallel to each other at positions shifted laterally from the welded part X in the longitudinal direction of the pipe 21. It is arranged toward.

  The data processing system 2 has a display device 6 such as a pulse generator 3, a preamplifier 4, a computer 5, and a monitor. The pulse generator 3 outputs one pulse of the burst wave, and generates an ultrasonic wave (pulse wave) from the probe 13 a through the probe 13.

  The preamplifier 4 functions as a signal amplification unit that amplifies the transmitted wave (analog signal) obtained by the non-contact ultrasonic sensor 1. In this example, the preamplifier 4 uses an 80 dB preamplifier with a frequency filter.

  The computer 5 is a general-purpose computer including a CPU, a memory, a hard disk device, a communication interface, and the like. In addition to the operating system (OS), the hard disk device is installed with software that samples the signal of the transmitted wave amplified by the preamplifier 4, performs graphic processing, visualizes it as a waveform, and outputs the waveform to the display device 6.

  In addition, in order to visualize the signal of the transmitted wave, for example, an oscilloscope or an oscillograph may be connected in addition to the computer.

  The software reads the data of the movement position of the moving mechanism 10 in the circumferential direction of the pipe 21 counted by the rotary encoder 11 and associates the waveform of the transmitted wave and the data of the movement position inputted at that time into the memory. It has a function to memorize. The display device 6 displays the waveform of the transmitted wave signal input from the computer 5 on the screen.

  The data processing system 2 outputs (visualizes) the transmitted wave obtained by the non-contact ultrasonic sensor 1 and the position data in the circumferential direction of the pipe 21 moved by the moving mechanism 10.

Here, the operation principle of the nondestructive inspection apparatus will be described with reference to FIG.
In this embodiment, as shown in FIG. 3, ultrasonic waves are transmitted and received obliquely with respect to the flaw detection surface 21 a of the pipe 21. The welded part X of the pipe 21 has substantially the same acoustic characteristics as the steel plate that is the base material of the pipe 21 with respect to the ultrasonic wave, and therefore the influence of the reflection of the welded part X itself hardly occurs.

  On the other hand, when the scratch 51 exists in the inner layer of the steel plate, the ultrasonic wave emitted from the probe 13a is reflected by the scratch 51 and an echo 52 (reflected wave) appears. In this case, the echo 52 (reflected wave) and a transmitted wave (not shown) that has passed through the inner layer of the steel sheet are received by the probe 14a.

  The types of ultrasonic waves include a longitudinal wave 53, a transverse wave 54, and a secondary creeping wave 55. The longitudinal wave 53 has a higher sound speed than the transverse wave 54 and is suitable for detecting deep defects. The secondary creeping wave 55 is a converted wave generated when the transverse wave 54 is reflected by the bottom surface 21b (lower surface) of the inner layer of the steel sheet, and is suitable for detecting shallow defects on the bottom surface 21b side.

  The position of the scratch 51 can be obtained from the incident angle of the beam and the path length. The shape of the scratch 51 can be inferred from the height and spread of the echo 52.

  Therefore, by using the longitudinal wave, the transverse wave, and the secondary creeping wave in combination, it is possible to perform an approximate sizing of the scratch 51 location. Further, when the waveform of the echo 52 appears, from the position where the non-contact ultrasonic sensor 1 moves from the starting point on the rail 20 with a hole around the pipe 21, the flaw 51 in the band of the welded part X of the pipe 21. The position (location) can be pinpointed.

Next, the operation of the nondestructive inspection apparatus of this embodiment will be described.
The inspection conditions are shown below.
The beam angle was 6.5 ° to 7 °, the voltage was 200 V, the transmission frequency of the pulse wave output from the probe 13a was 700 KHz to 900 KHz (in increments of 100 KHz), and the gain on the receiving side was 40.8 dB.

  Under this inspection condition, the moving mechanism 10 is moved to the starting point (moving position 0). By this movement, position data is sent from the rotary encoder 11 to the computer 5 and stored in the memory.

  When one pulse of the burst wave is output from the pulse generator 3 in accordance with an instruction from the computer 5, the burst wave is transmitted to the probe 13a through the probe 13 and an ultrasonic wave (pulse wave) is transmitted from the probe 13a. .

  This ultrasonic wave (pulse wave) is transmitted obliquely to the flaw detection surface 21 a of the pipe 21, travels through the inner layer of the pipe 21, and the transmitted wave that has passed through the inner layer of the steel sheet is received by the probe 14 a and output to the preamplifier 4. Is done.

  The preamplifier 4 amplifies the input transmitted wave signal and outputs the amplified signal to the computer 5. The computer 5 samples the transmitted wave signal amplified by the preamplifier 4, performs graphic processing, visualizes it as a waveform, outputs it to the display device 6, and displays the transmitted wave waveform on the screen of the display device 6. At this time, the computer 5 stores the waveform data of the transmitted wave and the data of the movement distance from the starting point in correspondence with each other.

  Normally, if there is no abnormality in the welded part or other part, as shown in FIG. 4, a vibration waveform 41 corresponding to one transmitted pulse appears. In the figure, the numerical value below the waveform is time.

  The operator visually confirms the waveform displayed on the display device 6 and confirms that there is no abnormality in the waveform. Subsequently, the moving mechanism 10 is moved by one hole of the rail 20 and the next pulse is transmitted. . This operation is repeated in order, and the circumference of the pipe 21 is measured and checked over the entire circumference.

  Then, when a waveform 42 other than the vibration waveform 41 of the normal transmitted wave appears at a certain position as shown in FIG. 5, the waveform 42 is generated when the transmitted wave is reflected by a defect site in the layer. The position of the defect can be pinpointed from the position of the welded part X and the moving position around the pipe 21.

As described above, according to this embodiment, since the welded part X of the pipe 21 can be inspected in a non-contact manner, the welded part X of the pipe 21 can be inspected even in a heated state, waiting for cooling as in the conventional contact type. It is possible to provide a nondestructive inspection apparatus and a nondestructive inspection method that can shorten the time and efficiently inspect the welded part X of the pipe 21.
Further, it is not necessary to apply oil or a jelly-like solvent to the surface of the pipe 21 as in the prior art, and the work time can be reduced accordingly.

  Although the embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  The software (program) installed in the hard disk device of the computer shown in the above embodiment may be stored in a computer-readable electronic medium: electronic media so that the computer can read the program from the electronic medium.

  Examples of the electronic medium include a recording medium such as a CD-ROM, flash memory, and removable media. Further, the configuration may be realized by distributing and storing components in different computers connected via a network, and communicating between computers in which the components are functioning.

  DESCRIPTION OF SYMBOLS 1 ... Non-contact type ultrasonic sensor, 2 ... Data processing system, 3 ... Pulse generator, 4 ... Preamplifier, 5 ... Computer, 6 ... Display apparatus, 10 ... Moving mechanism, 11 ... Rotary encoder, 12, 16 ... Gear , 13, 14 ... probes, 13a, 14a ... probes, 15 ... stays, 17 ... bogie parts, 20 ... rails with holes, 21 ... pipes, 21a ... flaw detection surfaces, 21b ... bottom surfaces.

Claims (5)

An ultrasonic sensor that is disposed apart from the surface of the part welded along the circumferential direction of the pipe, and receives a transmitted wave that has been transmitted through the pipe to the surface of the ultrasonic wave;
A moving mechanism for moving the ultrasonic sensor while measuring a moving position in a circumferential direction of the pipe;
A nondestructive inspection apparatus comprising: a data processing system that outputs a transmitted wave obtained by the ultrasonic sensor and circumferential position data of the pipe measured by the moving mechanism. The ultrasonic sensor is
A first probe for transmission that generates the ultrasonic wave, and a second probe for reception that receives a transmitted wave through which the ultrasonic wave generated by the first probe has passed through the inside of the pipe; The first probe and the second probe are arranged such that the transmission direction of the ultrasonic wave and the reception direction of the transmitted wave are substantially parallel and inclined with respect to the surface of the pipe. Item 1. The nondestructive inspection apparatus according to Item 1. The ultrasonic sensor is
The nondestructive inspection apparatus according to claim 1, wherein the nondestructive inspection apparatus is disposed at a position spaced apart from the portion by a predetermined distance in the longitudinal direction of the pipe. The data processing system includes:
The nondestructive inspection apparatus according to claim 1, further comprising means for visualizing a transmitted wave obtained by the ultrasonic sensor. An ultrasonic sensor disposed apart from the surface of the part welded along the circumferential direction of the pipe receives the transmitted wave transmitted through the pipe by the ultrasonic wave transmitted to the surface; ,
A step of moving the ultrasonic sensor while a moving mechanism measures a moving position in a circumferential direction of the pipe;
A non-destructive inspection method, comprising: outputting a transmitted wave obtained by the ultrasonic sensor and position data in the circumferential direction of the pipe measured by the moving mechanism.

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