JP2005106600A - Laser ultrasonic flaw detector and laser ultrasonic flaw detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform non-contact ultrasonic flaw detection at a narrow section, by using a laser ultrasonic method. <P>SOLUTION: The laser ultrasonic flaw detector comprises: a pulse ray emitting means 2; a pulse ray transmitting means 3; a pulse ray irradiating means 4; a ray emitting means 5 for emitting rays for inspecting ultrasonic waves generated in a body 1 to be inspected by pulse rays; a ray transmitting means 6; a ray transmission/reception means 7 for irradiating the body 1 to be inspected with rays and for receiving reflection rays modulated by ultrasonic waves, or the like for reflecting from defects; a moving means 8 for moving the pulse beam irradiating means 4 and the ray transmission/reception means 7; a travel mechanism controlling means 9 for determining an inspection part by controlling a travel direction and a travel speed; a reflection ray intensity measuring means 10 for separating reflection rays that are received by the ray transmission/reception means 7 and are transmitted by the ray transmitting means 6 into two portions and for measuring one reflection ray intensity; an ultrasonic detection means 11 for detecting ultrasonic waves from other reflection rays optically; a waveform recording means 12 for recording the waveform of ultrasonic waves; and a defect analysis display means 13 for analyzing and displaying defects from the waveform of the ultrasonic waves. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser ultrasonic flaw detection apparatus and a laser ultrasonic flaw detection method, and more particularly to a laser ultrasonic flaw detection apparatus and a laser ultrasonic flaw detection method that can be applied to an inspection object in a narrow place.

As a conventional ultrasonic flaw detector that detects a minute defect, an ultrasonic flaw detector using an array probe is known. This technique is described in Non-Patent Document 1, for example. A conventional ultrasonic flaw detector using an array probe, for example, combines ultrasonic waves transmitted from a plurality of probes that transmit ultrasonic waves for flaw detection of a defect to be inspected. 1 transmits an ultrasonic beam and scans the ultrasonic beam for flaw detection. The ultrasonic waves that have reflected the defect by scanning flaw detection are received by a plurality of probes, subjected to signal processing, and the flaw detection results are displayed and recorded. Since the ultrasonic flaw detector using such an array probe can scan an ultrasonic beam, a wide range of inspection is possible.
JP 2003-185639 A Ultrasonic Handbook Editing Committee, “Ultrasonic Handbook” August 30, 1999, published by Maruzen Co., Ltd., 430-435

  While the conventional ultrasonic flaw detector can perform a wide range of inspections, it is difficult to apply when the inspection object is in a narrow part because the size is large because it is composed of a plurality of probes. In particular, it is difficult to apply to inspection of narrow portions in water, radiation environment, high place, vacuum, corrosive environment and the like.

  On the other hand, Patent Document 1 discloses a flaw detection apparatus using a laser ultrasonic method. However, there is no disclosure as to how this can be applied to inspection of narrow areas in water, radiation environment, high place, vacuum, corrosive environment, and the like.

  Therefore, the object of the present invention is a non-contact method that can be applied to the inspection of a narrow portion that is difficult to inspect with a conventional apparatus in a water, a radiation environment, a high place, a vacuum, a corrosive environment, etc. using a laser ultrasonic method. It is an object to provide an ultrasonic flaw detection apparatus.

  The present invention achieves the above object, and the invention according to claim 1 comprises a pulse beam emitting means for emitting a pulse beam for generating an ultrasonic wave on an object to be inspected, and the pulse beam emitting means. A pulse light beam transmission means for transmitting the emitted pulse light beam, a pulse light beam irradiation means for irradiating the object with the pulse light beam transmitted by the pulse light beam transmission means, and a pulse light beam emitted from the pulse light beam irradiation means. A light beam emitting means for emitting a light beam for detecting an ultrasonic wave generated on the object to be inspected, a light beam transmission means for transmitting a light beam emitted from the light beam output means, and a light beam transmitted by the light beam transmission means. A light transmitting / receiving means for irradiating the object to be inspected and receiving reflected light modulated by an ultrasonic wave reflected, transmitted or diffracted by the defect; and the object to be inspected A moving means for changing the relative positional relationship between the pulsed light irradiation means and the light transmitting / receiving means and the object to be inspected according to the shape; and a moving mechanism control means for determining the examination site by controlling the moving direction and moving speed of the moving means. And reflected light intensity measuring means for separating the reflected light beam received by the light transmitting / receiving means at the examination site and transmitted by the light beam transmitting means, and measuring the reflected light intensity of one of the reflected light rays, and the reflected light intensity Ultrasonic detection means for optically detecting ultrasonic waves from the other reflected light beam separated by the measurement means; waveform recording means for recording the waveform of the ultrasonic waves detected by the ultrasonic detection means; and A laser ultrasonic flaw detector having defect analysis display means for analyzing and displaying defects from a waveform.

  Further, the invention according to claim 8 is a pulse light beam emitting step for emitting a pulse light beam for generating an ultrasonic wave on the object to be inspected, and a pulse light beam transmitting step for transmitting the pulse light beam emitted in the pulse light beam emitting step. And a pulse beam irradiation step for irradiating the object to be inspected with the pulse beam transmitted in the pulse beam transmission step, and detecting an ultrasonic wave generated in the object by the pulse beam irradiated in the pulse beam irradiation step. A light beam emitting step for emitting a light beam for performing, a light beam transmitting step for transmitting the light beam emitted from the light beam emitting step, and irradiating the object to be inspected with the light beam transmitted by the light beam transmitting step to reflect a defect or A beam transmitting / receiving step of receiving a reflected beam modulated by transmitted or diffracted ultrasonic waves; A moving step for changing the relative positional relationship between the position of pulsed light irradiation and light beam transmission / reception and the object to be inspected according to the shape of the object, and a movement for controlling the moving direction and moving speed of the moving step to determine the inspection site A reflected light intensity measurement step for measuring the reflected light intensity of one of the mechanism control step, the reflected light beam received by the light beam transmission / reception step at the examination site and separated by the light transmission step; An ultrasonic detection step for optically detecting an ultrasonic wave from the other reflected light beam separated in the reflected light intensity measurement step, a waveform recording step for recording the waveform of the ultrasonic wave detected in the ultrasonic wave detection step, and A defect analysis display step for analyzing and displaying defects from an ultrasonic waveform, and a laser ultrasonic flaw detection method. .

  According to the present invention, the pulse beam irradiation means for transmitting the pulse beam emitted from the pulse beam emission means to the pulse beam irradiation means can be constituted by a lens or a mirror. For this reason, a pulsed light irradiation means can be reduced in size. Similarly, the light emitted from the light emitting means can be transmitted to the light transmitting / receiving means by the light transmitting means, and the light transmitting / receiving means can be constituted by a lens or a mirror, so that the light transmitting / receiving means can be downsized. Since the pulse beam irradiation unit and the beam transmission / reception unit do not need to be in contact with the object to be inspected, the pulse beam irradiation unit and the beam transmission / reception unit are formed into the shape of the object to be inspected by controlling the movement unit by the movement mechanism control unit. Scanning can be performed together, and scanning flaw detection can be performed on the narrow portion.

First, a first embodiment of a laser ultrasonic flaw detector according to the present invention will be described with reference to FIG.
This laser ultrasonic flaw detector includes a pulsed beam emitting unit 2 that emits a pulsed beam for generating an ultrasonic wave on the object 1 and a pulsed beam transmitting unit 3 that transmits a pulsed beam emitted from the pulsed beam emitting unit 2. And pulsed light irradiation means 4 for irradiating the object 1 with the pulsed light transmitted by the pulsed light transmission means 3.

  Furthermore, this laser ultrasonic flaw detector transmits a light beam emitting means 5 for emitting a light beam for detecting an ultrasonic wave generated in the inspection object 1 by the irradiated pulse light beam, and a light beam emitted from the light beam emitting means 5. A light transmission means 6; and a light transmission / reception means 7 for irradiating the inspection object 1 with the light transmitted by the light transmission means 6 and receiving the reflected light modulated by the ultrasonic wave reflected, transmitted or diffracted by the defect. . Further, this laser ultrasonic flaw detector is inspected by controlling the moving direction and moving speed of the moving means 8 and the moving means 8 for moving the pulsed light irradiation means 4 and the light transmitting / receiving means 7 in accordance with the shape of the inspection object 1. And moving mechanism control means 9 for determining a part.

  Further, this laser ultrasonic flaw detector separates the reflected light received by the light transmitting / receiving means 7 at the inspection site and transmitted by the light transmitting means 6, and measures the reflected light intensity of one of them. Means 10, ultrasonic detection means 11 for optically detecting ultrasonic waves from the other reflected light beam, waveform recording means 12 for recording the waveform of the detected ultrasonic waves, and analysis and display of defects from the waveform of the ultrasonic waves And defect analysis display means 13 for performing.

The pulse beam emitting means 2 that emits a pulse beam for generating an ultrasonic wave on the inspection object 1 is composed of a pulse light source that instantaneously irradiates high-intensity pulse light. Examples of such light sources include solid-state pulse lasers such as Nd: YAG laser, Nd: YLF laser, Nd: YVO ₄ laser, Ti: Sapphire laser, and glass laser, and gas pulses such as XeCl, KrF, and ArF excimer lasers. A laser etc. are mentioned.

  The pulse beam transmission means 3 for transmitting the pulse beam emitted from the pulse beam emission means 2 includes an optical fiber and an optical element such as a lens or a mirror for causing the pulse beam emitted from the pulse beam emission means 2 to enter the optical fiber. And a housing for protecting the optical fiber. In addition, it can replace with an optical fiber and can also use the optical fiber bundle which bundled the optical fiber. In addition, a hollow tube can be used to spatially transmit pulsed light.

  FIG. 2 shows a configuration example of the pulse beam irradiation unit 4 that irradiates the test object 1 with the pulse beam transmitted by the pulse beam transmission unit 3. The pulsed light irradiation means 4 includes a lens 14 for collimating the light emitted from the optical fiber, a mirror 15 for reflecting the light, a lens 16 for collecting the light, and the inside and outside of the pulsed light irradiation means 4. And a window 17 for isolating.

  In FIG. 1, a light beam emitting means 5 that emits a light beam for detecting an ultrasonic wave generated on an object 1 to be inspected by an irradiated pulse light beam is composed of a light source that continuously emits light of a single wavelength. . Examples of such a light source include a solid-state laser excited by a semiconductor and a lamp, a gas laser such as an Ar laser and a He—Ne laser, and a semiconductor laser.

The light beam transmitting means 6 for transmitting the light beam emitted from the light beam emitting means 5 is composed of an optical fiber. In addition, a hollow tube can be used to spatially transmit light.
FIG. 3 shows a configuration example of the light transmitting / receiving means 7 that irradiates the inspection object 1 with the light transmitted by the light transmitting means 6 and receives the reflected light modulated by the ultrasonic wave reflected, transmitted, or diffracted by the defect. The light beam transmission / reception means 7 is composed of a lens 18 for collimating the light emitted from the optical fiber, a lens 19 for condensing the light, and a window 20 for isolating the inside and the outside of the light transmission / reception means 7. Is done.

  FIG. 4 shows a configuration example of the moving means 8 that moves the pulsed light irradiation means 4 and the light beam transmitting / receiving means 7 in accordance with the shape of the object 1 to be inspected. The moving means 8 includes a fixed plate 21 for fixing the pulse light beam irradiation means 4 and the light beam transmitting / receiving means 7, a rail 22 that holds the fixed plate 21, and a drive shaft 23 that drives the fixed plate 21 along the rail 22. And a motor 24 for driving the drive shaft 23.

  The moving mechanism control means 9 (FIG. 1) that determines the examination site by controlling the moving direction and moving speed of the moving means 8 includes an output circuit that outputs a voltage or current for rotating the motor 24, and a voltage or current. It is composed of a control circuit for controlling. The control circuit can also be configured by a computer.

  FIG. 5 shows an example of the configuration of the reflected light intensity measuring means 10 that separates the reflected light that is received by the light transmitting / receiving means 7 and transmitted by the light transmitting means 6 at the inspection site and measures the intensity of one reflected light. Show. The reflected light intensity measuring means 10 includes a lens 25 for making the light emitted from the light transmitting means 6 into parallel light, beam splitters 26 and 27 for separating the light into transmitted light and reflected light, and for detecting the light. And a photodetector 28.

  In FIG. 1, the ultrasonic detection means 11 for optically detecting ultrasonic waves from the other reflected light is composed of an optical detection device such as a Fabry-Perot interferometer or a photorefractive interferometer. For example, a Fabry-Perot interferometer acts as an optical bandpass filter. The reflected light modulated by the ultrasonic wave has its frequency changed by the Doppler effect. For this reason, by acting as an optical bandpass filter, it is possible to detect ultrasonic waves by measuring the frequency change of the reflected light as a change in the amount of transmitted light with a photodetector.

  The waveform recording means 12 for recording the detected ultrasonic waveform is composed of a device for converting the ultrasonic waveform signal output from the photodetector into digital data and recording it. Examples of such a device include a digital or analog oscilloscope, a general-purpose computer equipped with an AD converter (analog / digital converter), an AD converter equipped with a storage device, and the like.

  The defect analysis display means 13 for analyzing and displaying defects from the ultrasonic waveform is constituted by a device for converting the ultrasonic waveform signal output from the photodetector into digital data and analyzing it. Examples of such a device include a general-purpose computer equipped with an AD converter, a dedicated analysis device, and the like.

Next, the operation of the laser ultrasonic flaw detector according to the first embodiment configured as described above will be described.
The pulsed beam emitted from the pulsed beam emitting unit 2 enters the pulsed beam transmission unit 3 and is transmitted to the pulsed beam irradiation unit 4 with high efficiency. The pulse light beam transmitted to the pulse light beam irradiation means 4 is emitted from the pulse light beam transmission means 3 and converted into parallel light by the lens 14 shown in FIG. Then, after being reflected at right angles by the lens 15, it is condensed by the lens 16, passes through the window 17, and is irradiated onto the device under test 1. Note that the window 17 transmits the pulsed light and acts to isolate the lens 14, the mirror 15, and the lens 16 from the outside.

  Ultrasound is generated at the point of irradiation of the pulsed light beam of the object 1 due to the thermoelastic effect or ablation. When the pulse light beam on the inspection object 1 is circular, the ultrasonic wave isotropically propagates concentrically around the irradiation point of the pulse light beam. On the other hand, when it is desired to propagate the ultrasonic wave with directivity, the shape of the pulse light beam on the object 1 is made linear or rectangular.

  On the other hand, the light beam emitted from the light beam emitting means 5 for detecting the ultrasonic wave is transmitted to the reflected light intensity measuring means 10. The reflected light intensity measuring means 10 is reflected by the beam splitter 27 shown in FIG. Then, the light is condensed by the lens 25 and enters the light beam transmission means 6. The light beam incident on the light beam transmission means 6 is transmitted to the light beam transmission / reception means 7.

  In the light transmitting / receiving means 7, after being converted into parallel light by the lens 18 shown in FIG. 3, the light is condensed by the lens 19, passes through the window 20, and is irradiated onto the object 1. The window 20 has a function of transmitting light rays and isolating the lenses 18 and 19 from the outside, like the window 17.

  Here, when the ultrasonic wave passes through the irradiation point of the light beam of the inspection object 1, the frequency of the reflected light beam is modulated by the amplitude fluctuation of the ultrasonic wave. The modulated reflected light beam travels in a path opposite to the light beam, passes through the window 20, is collimated by the lens 19, is collected by the lens 18, and enters the light transmission means 6. The reflected light beam transmitted by the light beam transmission means 6 enters the reflected light intensity measurement means 10.

  In the reflected light intensity measuring means 10, as shown in FIG. 5, the reflected light is collimated by the lens 25 and then divided into a reflected component and a transmitted component by the beam splitter 26. The transmitted component passes through the beam splitter 27 and is detected by the photodetector 28. On the other hand, the reflection component is detected by the ultrasonic detection means 11. The ultrasonic detector 11 detects a change in the frequency of the reflected component as a change in the amount of transmitted light and outputs an electrical signal.

  This electric signal is transmitted to the waveform recording means 12. When the defect reflection ultrasonic waves are detected, the waveform recording means 12 can obtain an ultrasonic waveform as shown in FIG. 6, for example. In FIG. 6, the waveform positioned at time: 17 μs is the ultrasonic signal 29 for defect reflection. The waveform of time: 10 μs is an ultrasonic signal 30 that reaches the irradiation point of the light beam by the shortest path from the irradiation point of the pulsed light beam. Each ultrasonic waveform measured for each irradiation of the pulsed beam is appropriately recorded in the waveform recording means 12 as digital data.

  On the other hand, the moving mechanism control means 9 moves the moving means 8 in three directions of up and down, left and right, and front and rear based on the inputted moving direction and moving speed. A position signal indicating each position in the three directions is transmitted to the defect analysis display means 13.

  The defect analysis display unit 13 measures the ultrasonic waveform output from the ultrasonic detection unit 11 in synchronization with the trigger signal output from the pulsed beam emission unit 2. In this case, since there is a time delay between the pulse beam emitting means 2 emitting the pulse beam and measuring the ultrasonic waveform, the ultrasonic waveform is measured after a certain delay time. Further, depending on the part of the object 1 to be inspected, the surface state is different, and the sensitivity of the ultrasonic detection means 11 changes. For this reason, the intensity signal of the reflected light beam detected by the photodetector 28 is transmitted to the defect analysis display means 13 so as to correct the amplitude intensity of the ultrasonic waveform measured at each part. As a result, the defect analysis display means 13 measures and corrects the ultrasonic waveform measured and corrected in each part, based on the position signal output from the movement mechanism control means 9, for example, as shown in FIG. The visualized image 31 can be obtained.

As a result of the operation described above, the pulsed light emitted from the pulsed light emitting means 2 can be transmitted to the pulsed light irradiation means 4 by the pulsed light transmission means 3, and the pulsed light irradiation means 4 can be constituted by the lenses 14 and 16 and the mirror 15. Therefore, the pulse beam irradiation means 4 can be reduced in size. Similarly, the light emitted from the light emitting means 5 can be transmitted to the light transmitting / receiving means 7 by the light transmitting means 6, and the light transmitting / receiving means 7 can be constituted by the lenses 18 and 19, so that the light transmitting / receiving means 7 can be downsized. Can do. Since the pulse beam irradiation means 4 and the light beam transmission / reception means 7 do not need to be in contact with the object to be inspected, the movement mechanism control means 9 controls the movement means 8 so that the small pulse beam irradiation means 4 and the light beam transmission / reception means are provided. 7 can be scanned in accordance with the shape of the object to be inspected, and scanning flaw detection can be performed on the narrow portion.
As a result, it becomes possible to perform non-contact flaw detection of the narrow portion in accordance with the shape of the object 1 to be inspected in water, in a radiation environment, in a high place, in a vacuum, or in a corrosive environment.

  Subsequently, another operation of the laser ultrasonic flaw detector according to the first embodiment will be described.

  In the defect analysis display means 13, for example, an image shown in FIG. 8 may be obtained. Here, it can be estimated that the progress direction of the defect 32 extends in the upper right direction in FIG. This estimation may be automatically performed based on the defect database and empirical rules so far, or may be manually performed at the discretion of the inspector. In addition, estimation may be performed for each irradiation of a pulsed light beam, or estimation may be performed for each fixed number of irradiations. Then, the movement distance in the horizontal direction and the vertical direction is determined so as to move in the upper right direction in which the defect 32 extends from the estimation result, a movement command signal is transmitted to the movement mechanism control means 9, and the movement means 8 is moved. Measure the sound wave meter. As a result, a visualized image of the defect can be obtained as in FIG.

As a result of the action described above, the shape of the defect 32 can be grasped from the output image result of the defect analysis display means 13, and the progress direction can be estimated automatically or manually. Then, the scanning distance is determined in accordance with the shape of the defect 32 by determining the movement distance in the horizontal direction and the vertical direction so as to move in the direction in which the defect 32 advances, and moving the moving means 8 by the moving mechanism control means 9. Is possible.
As a result, it is possible to perform efficient non-contact flaw detection of the narrow portion in accordance with the shape of the object to be inspected 1 in water, in a radiation environment, in a high place, in a vacuum, or in a corrosive environment.

Subsequently, still another operation of the laser ultrasonic flaw detector according to the first embodiment will be described.
In the defect analysis display means 13, for example, an image shown in FIG. 9 may be obtained. Here, the linear image 33 extending in the lower right direction in FIG. 9 can be estimated as a reflected ultrasonic wave from the concavo-convex portion, corner portion, or the like of the device under test 1 for reasons such as a mechanical shape. This estimation may be performed automatically based on the drawings stored in the defect analysis display means 13, or may be performed manually at the discretion of the inspector. In the case of FIG. 9, it can be estimated that the structure is closer as it scans in the horizontal direction.

  Further, the distance to the structure can be obtained from the measurement time of the linear image 33, and as a result, the current examination site can be identified from the drawing of the examination site. Further, by referring to the information of the past movement direction, distance, and speed stored in the movement mechanism control means 9, the examination site so far can be identified. Identification may be performed automatically based on the drawings stored in the defect analysis display means 13, or may be performed manually at the discretion of the inspector. The present and past inspection sites can be displayed as images on the defect analysis display means 13 as necessary.

As a result of the above-described operation, the current examination site can be determined from the distance and direction to the linear image 33 by comparing the drawing of the examination site with the linear image 33 that is reflected from the uneven part and the corner part and visualized. Can be identified. Further, by referring to the information on the current examination site and the past movement direction, distance, and speed stored in the moving mechanism control means 9, the previous examination site can be identified.
As a result, it is possible to perform efficient non-contact flaw detection of the narrow portion in accordance with the shape of the object to be inspected 1 in water, in a radiation environment, in a high place, in a vacuum, or in a corrosive environment.

  Next, a second embodiment of the laser ultrasonic flaw detector according to the present invention will be described with reference to FIG. However, in each of the following embodiments, the same or similar parts as those in the first embodiment are denoted by common reference numerals, and redundant description is omitted.

  In this laser ultrasonic flaw detector, the object to be inspected 1 is output by an output signal of the moving mechanism control means 9 or an external signal in place of the pulse beam emitting means 2 of the laser ultrasonic flaw detector (FIG. 1) of the first embodiment. Has an externally synchronized pulse beam emitting means 34 for emitting a pulse beam for generating an ultrasonic wave. Further, the laser ultrasonic flaw detector has an ultrasonic waveform holding means 35 for controlling the temporary holding of the ultrasonic waveform detected by the ultrasonic detection means 11 and the transmission to the defect visualization display means 13.

  An externally synchronized pulse beam emitting unit 34 that emits a pulse beam for generating ultrasonic waves in the object 1 to be inspected by an output signal of the moving mechanism control unit 9 or an external signal operates in response to the external input signal and emits a pulse beam. It consists of a pulsed light source. Examples of such a light source include a solid-state laser such as a flash lamp excitation Nd: YAG laser. In a flash lamp-pumped solid-state laser, the flash lamp is turned on to excite the laser medium, and a pulse beam is emitted by a method such as a Q switch. For this reason, the emission of the pulsed light beam can be controlled by controlling the lighting of the flash lamp by the external input signal.

  The ultrasonic waveform holding means 35 for controlling the temporary holding of the ultrasonic waveform detected by the ultrasonic detection means 11 and the transmission to the defect visualization display means 13 is an AD converter for converting an electric signal into digital data. A memory or a hard disk for holding the digital data, a control device for controlling the holding and transmission of the held digital data, and a DA converter for returning the digital data to analog data. The DA converter may not be provided.

The operation of the laser ultrasonic flaw detector according to the second embodiment configured as described above will be described.
There are cases where it is desired to change the inspection accuracy and the inspection interval according to the inspection site. In this case, first, the inspection pitch at each inspection site and the number of inspections at each point are determined. The number of inspections is the number of times the ultrasonic waveform is measured at each point. By averaging the ultrasonic waveform by the number of times of measurement, the signal noise ratio (S / N ratio) of the ultrasonic waveform can be improved to improve the inspection accuracy. it can.

  Next, the movement amount of the moving means 8 is set from the inspection pitch, the emission timing and frequency of the externally synchronized pulse beam emitting means 34 are set from the number of inspections, and in addition to this, the moving direction and moving speed of the moving means 8 are set. Input to means 9. These inputs can be input all at once before the flaw detection, or can be performed during the flaw detection. Based on these input values, the moving mechanism control means 9 moves the moving means 8 while emitting pulsed light from the externally synchronized pulsed light emitting means 34 to perform scanning flaw detection. As a result, scanning flaw detection can be performed while changing the inspection accuracy and the inspection interval according to the inspection site.

As a result of the operation described above, the inspection accuracy and the inspection interval are set according to the shape of the inspection site by controlling the output of the pulse light of the externally synchronized pulse light emission means 34 by the output signal of the moving mechanism control means 9. It becomes possible to do.
As a result, it becomes possible to perform non-contact flaw detection of the narrow portion in accordance with the shape of the object 1 to be inspected in water, in a radiation environment, in a high place, in a vacuum, or in a corrosive environment.

Subsequently, another operation of the laser ultrasonic flaw detector according to the second embodiment will be described.
In some cases, it is desired to display the inspection result of the inspection site after scanning each inspection site. In this case, the moving mechanism control unit 9 transmits a scanning start signal to the ultrasonic waveform holding unit 35 simultaneously with the start of scanning of the examination site. The ultrasonic waveform holding means 35 starts holding the ultrasonic waveform based on this signal. On the other hand, the moving mechanism control means 9 moves the moving means 8 to emit a pulsed light from the externally synchronized pulsed light emitting means 34 to scan and inspect the inspection site.

  Subsequently, a scanning end signal is transmitted from the moving mechanism control unit 9 to the ultrasonic waveform holding unit 35 when scanning of the examination site is completed. The ultrasonic waveform holding means 35 transmits the temporarily held ultrasonic waveform to the defect visualization display means 13 based on this signal. The defect visualization display unit 13 displays and records a visualized image and an inspection result as shown in FIG. 7, for example, before a scanning start signal for the next inspection site is output. As a result, the ultrasonic waveform and the inspection result can be displayed on the defect visualization display unit 13 for each inspection site. Further, since the operation / control work of the moving mechanism control means 9 and the defect evaluation / consideration work using the defect visualization display means 13 can be separated, it is possible to reduce work mistakes of the inspector.

As a result of the operation described above, the ultrasonic waveform holding means 35 can control the holding and transmission of the ultrasonic waveform output from the ultrasonic detection means 11 by the output signal of the moving mechanism control means 9. For this reason, it becomes possible to display the ultrasonic waveform and the inspection result on the defect visualization display means 13 for each inspection region in accordance with the shape of the inspection region.
As a result, it becomes possible to perform non-contact flaw detection of the narrow portion in accordance with the shape of the object 1 to be inspected in water, in a radiation environment, in a high place, in a vacuum, or in a corrosive environment.

  Further, since the operation / control work of the moving mechanism control means 9 and the defect evaluation / consideration work using the defect visualization display means 13 can be separated, it is possible to reduce the work mistakes of the inspector.

Next, a third embodiment of the laser ultrasonic flaw detector according to the present invention will be described with reference to FIGS.
In the present embodiment, the cylindrical tube 36 is an inspection object, and the circumferential opening defect 37 is detected. In addition to the linear opening defect 37, the cylindrical tube 36 has an edge 38 formed by processing in the circumferential direction.

  This laser ultrasonic flaw detector includes a pulse beam emitting unit 2 that emits a pulse beam for generating an ultrasonic wave in the cylindrical tube 36, and a pulse beam transmission unit 3 that transmits the pulse beam emitted from the pulse beam emitting unit 2. And a pulse beam irradiation unit 4 for irradiating the cylindrical tube 36 with the pulse beam transmitted by the pulse beam transmission unit 3.

  The laser ultrasonic flaw detector further includes a light beam emitting means 5 for emitting a light beam for detecting an ultrasonic wave generated in the cylindrical tube 36 by the irradiated pulse light beam, and a light beam for transmitting the light beam emitted from the light beam emitting means 5. The transmission means 6 and the light transmission / reception means 7 for irradiating the cylindrical tube 36 with the light transmitted by the light transmission means 6 and receiving the reflected light modulated by the ultrasonic wave reflected, transmitted or diffracted by the defect.

  Further, this laser ultrasonic flaw detector is attached to the fixing means 39 and the fixing means 39 fixed to the cylindrical tube 36 in order to move the pulsed light irradiation means 4 and the light transmitting / receiving means 7 in accordance with the shape of the cylindrical tube 36. The driving means 40 for driving in accordance with the shape of the cylindrical tube 36, the angle adjusting means 41 for adjusting the vertical and horizontal angles of the pulse light irradiation means 4 and the light transmitting / receiving means 7, and the vertical length adjustment. Length adjusting means 42, distance adjusting means 43 for adjusting the distance in the front-rear direction, arrangement adjusting means 44 for adjusting the arrangement relationship, and the moving direction and moving speed of the driving means 40 to control the examination site And moving mechanism control means 9 for determining.

The fixing means 39 can be fixed to and removed from the cylindrical tube 36. The fixing method includes a mechanical fixing method such as a hydraulic method or an air method, or an electromagnetic fixing method.
The driving means 40 is rotated in the circumferential direction of the cylindrical tube 36 by a motor such as a stepping motor, a servo motor, or an ultrasonic motor. The rotation direction, rotation speed, rotation / stop, etc. of the drive means 40 are controlled by the movement mechanism control means 9.

  In the angle adjusting means 41, the length adjusting means 42, and the distance adjusting means 43, the angle, length, and distance can be manually adjusted in advance and fixed. Further, the position can be adjusted by a motor such as a stepping motor, a servo motor, or an ultrasonic motor. Position adjustment by the motor can be performed by the moving mechanism control means 9 even during scanning flaw detection.

  The arrangement relationship between the pulse beam irradiation unit 4 and the beam transmission / reception unit 7 includes the arrangement shown in FIGS. 12 and 13 and the arrangement rotated by a certain angle, and can be manually adjusted and fixed in advance. The arrangement adjusting unit 44 adjusts the arrangement relationship between the pulsed beam irradiation unit 4 and the beam transmitting / receiving unit 7. Further, the arrangement of the pulse light beam irradiation means 4 and the light beam transmission / reception means 7 can be appropriately adjusted by a motor such as a stepping motor, a servo motor, or an ultrasonic motor. The placement adjustment by the motor can be performed by the moving mechanism control means 9 even during scanning flaw detection.

The operation of the laser ultrasonic flaw detector according to the third embodiment configured as described above will be described.
When inspecting a specific part of the cylindrical tube 36, the laser ultrasonic flaw detector is fixed to the cylindrical tube 36 by the fixing means 39. Then, the angle adjusting means 41, the length adjusting means 42, and the distance adjusting means 43 are adjusted manually or automatically so that the target inspection site can be scanned, and the positions of the pulsed light irradiation means 4 and the light transmitting / receiving means 7 are adjusted. Thereafter, the driving mechanism 40 is driven by the moving mechanism control means 9 to scan and inspect the target inspection site. The operation procedure and the operation amount of the angle adjusting unit 41, the length adjusting unit 42, and the distance adjusting unit 43 are input in advance to the moving mechanism control unit 9, and the target inspection site is automatically scanned by the moving mechanism control unit 9. You can also detect flaws. In addition, the angle adjusting means 41, the length adjusting means 42, and the distance adjusting means 43 can be adjusted at any time, and the positions of the pulsed light irradiating means 4 and the light transmitting / receiving means 7 can be adjusted at any time to perform scanning flaw detection.

  As a result of the scanning flaw detection, the defect analysis display means 13 can obtain, for example, a visualized image shown in FIG. The defect image 45 is an image of a linear opening defect 37, and the linear image 46 is an image of an edge 38 formed by processing.

As a result of the operation described above, the positions of the pulse beam irradiation unit 4 and the beam transmission / reception unit 7 are adjusted by the angle adjustment unit 41, the length adjustment unit 42, and the distance adjustment unit 43, and moved by the drive unit 40, whereby the pulse The light beam irradiation means 4 and the light beam transmission / reception means 7 can be moved in accordance with the shape of the cylindrical tube 36, and scanning flaw detection is possible in the narrow portion.
As a result, it is possible to perform efficient non-contact flaw detection of the narrow portion matching the shape of the cylindrical tube 36 in water, radiation environment, high place, vacuum, corrosive environment, and the like.

  Subsequently, another operation of the laser ultrasonic flaw detector according to the third embodiment will be described.

  There are cases where the ultrasonic waves generated by the pulsed light irradiation means 4 have directivity. In this case, the moving mechanism control means 9 controls the arrangement adjusting means 44 manually or by a motor to adjust the arrangement relationship between the pulse light beam irradiation means 4 and the light beam transmitting / receiving means 7, and controls the directivity of the ultrasonic wave to perform scanning flaw detection. To do. As a result, the defect analysis display means 13 can obtain, for example, a visualized image of the defect shown in FIG.

As a result of the operation described above, the propagation direction of the ultrasonic waves can be adjusted by adjusting the arrangement relationship between the pulse beam irradiation unit 4 and the beam transmitting / receiving unit 7 by the arrangement adjustment unit 44, and defects extending in each direction can be detected. It becomes possible to detect flaws efficiently.
As a result, it is possible to perform efficient non-contact flaw detection of the narrow portion matching the shape of the cylindrical tube 36 in water, radiation environment, high place, vacuum, corrosive environment, and the like.

  In each of the embodiments described above, the device under test 1 is fixed, and the pulse light beam irradiation means 4 and the light beam transmission / reception means 7 are moved by the movement means 8. However, in the present invention, since the pulse beam irradiation means 4 and the beam transmission / reception means 7 need only move relative to the object 1 to be inspected, the pulse beam irradiation means 4 and the beam transmission / reception means 7 are fixed, It is also possible to move the inspection body 1.

1 is a block diagram showing a first embodiment of a laser ultrasonic inspection device according to the present invention. The typical longitudinal cross-sectional view which shows the structural example of the pulse beam irradiation means in FIG. The typical longitudinal cross-sectional view which shows the structural example of the light beam transmission-and-reception means in FIG. The typical longitudinal section showing the example of composition of the movement means in Drawing 1. The typical longitudinal section showing the example of composition of the reflected light intensity measurement means in Drawing 1. The graph which shows the example of the ultrasonic waveform obtained by the 1st Embodiment of this invention. The figure which shows the example of the visualization image of the defect obtained by the 1st Embodiment of this invention. The figure which shows the example of the image which the defect analysis display means in the 1st Embodiment of this invention outputs. The figure which shows the example of the visualization image in the 1st Embodiment of this invention. The block diagram which shows 2nd Embodiment of the laser ultrasonic flaw detector which concerns on this invention. The elevational view which shows 3rd Embodiment of the laser ultrasonic flaw detector which concerns on this invention. FIG. 12 is an elevational sectional view showing an example of the arrangement relationship between the pulse beam irradiation unit and the beam transmission / reception unit in FIG. FIG. 12 is an elevational sectional view illustrating another example of the arrangement relationship between the pulsed beam irradiation unit and the beam transmitting / receiving unit in FIG. 11. The figure which shows the example of the visualization image of the defect obtained by the 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Test object, 2 ... Pulse light beam emission means, 3 ... Pulse light beam transmission means, 4 ... Pulse light beam irradiation means, 5 ... Light beam emission means, 6 ... Light beam transmission means, 7 ... Light beam transmission / reception means, 8 ... Movement means, DESCRIPTION OF SYMBOLS 9 ... Movement mechanism control means, 10 ... Reflected light intensity measurement means, 11 ... Ultrasonic detection means, 12 ... Waveform recording means, 13 ... Defect analysis display means, 14 ... Lens, 15 ... Mirror, 16 ... Lens, 17 ... Window , 18 ... lens, 19 ... lens, 20 ... window, 21 ... fixed plate, 22 ... rail, 23 ... drive shaft, 24 ... motor, 25 ... lens, 26 ... beam splitter, 27 ... beam splitter, 28 ... photodetector 29 ... Ultrasonic signal of defect reflection, 30 ... Ultrasonic signal, 31 ... Visualized image of defect, 32 ... Defect, 33 ... Linear image, 34 ... External sync pulse beam emitting means, 35 ... Preservation of ultrasonic waveform Step: 36 ... Cylindrical tube, 37 ... Linear opening defect, 38 ... Edge, 39 ... Fixing means, 40 ... Driving means, 41 ... Angle adjusting means, 42 ... Length adjusting means, 43 ... Distance adjusting means, 44 ... Arrangement adjusting means, 45... Defect image, 46.

Claims (8)

A pulse beam emitting means for emitting a pulse beam for generating ultrasonic waves on the object to be inspected;
Pulse light transmission means for transmitting the pulse light emitted from the pulse light emission means;
Pulse light beam irradiation means for irradiating the object with the pulse light beam transmitted by the pulse light beam transmission means;
A light beam emitting means for emitting a light beam for detecting an ultrasonic wave generated on the object by the pulse light beam irradiated from the pulse light beam irradiation means;
A light beam transmitting means for transmitting a light beam emitted from the light beam emitting means;
A light transmitting / receiving means for irradiating the inspection object with a light beam transmitted by the light beam transmitting means and receiving a reflected light beam modulated by an ultrasonic wave reflected, transmitted or diffracted by a defect;
A moving means for changing the relative positional relationship between the pulsed light irradiation means and the light transmitting / receiving means and the test object in accordance with the shape of the test object;
A moving mechanism control means for determining an examination site by controlling a moving direction and a moving speed of the moving means;
Reflected light intensity measuring means for separating the reflected light beam received by the light beam transmitting / receiving means at the inspection site and transmitted by the light beam transmitting means, and measuring the reflected light intensity of one of the two,
Ultrasonic detection means for optically detecting ultrasonic waves from the other reflected light beam separated by the reflected light intensity measurement means;
Waveform recording means for recording the waveform of the ultrasonic wave detected by the ultrasonic wave detection means;
Defect analysis display means for analyzing and displaying defects from the ultrasonic waveform;
A laser ultrasonic flaw detector characterized by comprising:   2. The laser ultrasonic flaw detector according to claim 1, wherein the pulse beam emitting means is configured to control the emission of the pulse beam by an output signal of the moving mechanism control means or an external signal. Laser ultrasonic flaw detector.   3. The laser ultrasonic flaw detector according to claim 1, wherein the ultrasonic waveform detected by the ultrasonic detection unit is temporarily stored and transmitted to the defect visualization display unit based on an output signal of the moving mechanism control unit. A laser ultrasonic flaw detector characterized by further comprising an ultrasonic waveform holding means for controlling.   The laser ultrasonic flaw detector according to any one of claims 1 to 3, wherein the moving mechanism control means determines a next inspection site based on an output result of the defect analysis display means. Laser ultrasonic flaw detector.   5. The laser ultrasonic flaw detector according to claim 1, wherein the defect analysis display means compares the detected ultrasonic waveform with a pre-stored drawing of the inspection site, and compares the past and present. A laser ultrasonic flaw detector characterized by being configured to display an examination site.   6. The laser ultrasonic flaw detector according to claim 1, wherein the moving means includes a fixing means for fixing the moving means to the object to be inspected, and a shape of the object to be inspected attached to the fixing means. A laser ultrasonic flaw detector characterized by comprising: drive means for driving together; and position adjusting means attached to the drive means for adjusting the position by attaching the pulse light beam irradiating means and the light beam transmitting / receiving means.   7. The laser ultrasonic flaw detector according to claim 6, wherein the position adjusting means includes an arrangement adjusting means for adjusting an arrangement relationship between the pulse light beam irradiating means and the light beam transmitting / receiving means. . A pulse beam emitting step for emitting a pulse beam for generating ultrasonic waves on the object to be inspected;
A pulse beam transmission step for transmitting the pulse beam emitted in the pulse beam emission step;
A pulsed light irradiation step of irradiating the object with the pulsed light transmitted by the pulsed light transmission step;
A light beam emitting step of emitting a light beam for detecting an ultrasonic wave generated in the inspection object by the pulse light beam irradiated in the pulse light beam irradiation step;
A light beam transmitting step for transmitting the light beam emitted from the light beam emitting step;
A light beam transmitting / receiving step of irradiating the inspection object with the light beam transmitted by the light beam transmission step and receiving a reflected light beam modulated by an ultrasonic wave reflected, transmitted or diffracted by a defect;
A moving step of changing a relative positional relationship between the position of the pulsed light irradiation and light beam transmission / reception and the test object in accordance with the shape of the test object;
A moving mechanism control step for determining the examination site by controlling the moving direction and moving speed of the moving step;
A reflected light intensity measuring step for receiving the light at the inspection site by a light transmitting / receiving step and separating the reflected light transmitted by the light transmitting step into two, and measuring one of the reflected light intensities;
An ultrasonic detection step for optically detecting ultrasonic waves from the other reflected light beam separated in the reflected light intensity measurement step;
A waveform recording step for recording the waveform of the ultrasonic wave detected in the ultrasonic wave detection step;
A defect analysis display step for analyzing and displaying defects from the ultrasonic waveform;
A laser ultrasonic flaw detection method comprising:

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