JP7427745B1 - Ultrasonic testing device and method - Google Patents

Abstract

The present invention provides an ultrasonic inspection technique that can improve the measurement accuracy and measurement speed of ultrasonic inspection for quality assurance of welded parts. [Solution] An ultrasonic inspection device 1 is configured to generate ultrasonic waves by irradiating a measurement object 2 having at least two base materials 3 joined to each other by welding and a welded joint construction part 4. A transmitting light source 10 that oscillates a transmitting laser beam Lt, a receiving light source 11 that oscillates a receiving laser beam Lr for irradiating the measurement object 2 to perform measurement with ultrasonic waves, and measuring the receiving laser beam Lr. an interference measuring section 12 that interferometrically measures the return light reflected when the object 2 is irradiated and extracts an ultrasonic signal; and an evaluation section 29 that evaluates at least the size of the joining construction section 4 based on the ultrasonic signal. , and at least one of the respective irradiation areas irradiated with the transmitting laser beam Lt and the receiving laser beam Lr is expanded to include the boundary 5 between the base material 3 and the joining part 4. [Selection diagram] Figure 1

Description

Embodiments of the present invention relate to ultrasonic inspection techniques.

BACKGROUND ART Ultrasonic measurement methods using laser light, so-called laser ultrasound methods, are useful for inspecting narrow areas or high-temperature areas because they enable non-contact and non-destructive ultrasonic inspection. On the other hand, local joining techniques such as laser welding or spot welding play an important role among manufacturing techniques. However, there is a need for quality assurance, especially technology for accurately measuring the health of joints at high speed without affecting the process. The laser ultrasound method is considered to be effective for high-speed joint measurement because of its non-contact inspection feature.

In the automobile industry, bonding technology is widely used, and various techniques related to quality assurance have been reported. For example, spot welds are measured using airborne ultrasound, which allows non-contact measurement. Similar to laser ultrasound, this aerial ultrasound enables non-contact measurement and does not require irradiation of light onto the target surface, so high-speed and stable measurement results are expected. However, as the frequency increases, the attenuation rate in the air increases, so high frequencies cannot be used. For this reason, there is a problem that it cannot be used to measure a small object with a welding amount of several mm in diameter.

As a similar measurement method using this laser ultrasound method, there is a known technology in which a laser beam for transmitting ultrasonic waves and a laser beam for receiving ultrasonic waves are placed opposite each other across the welded part to transmit and receive ultrasonic waves. ing. For example, fix the irradiation position of the receiving laser beam on the edge of the weld, scan the transmitting laser beam across the weld, and observe the change trend of the ultrasonic waves obtained at each transmitting position. Measure the weld width. This laser ultrasound does not cause the problems caused by the air ultrasound described above, but the irradiation position of the receiving laser beam is limited to the edge of the weld, and in cases where the weld changes slightly every time, Difficult to make stable measurements. Furthermore, a mechanism for highly accurate measurement and positioning is required for stable measurement. Furthermore, there is a problem that it takes time to measure one welded part because the transmitting laser beam is scanned.

Japanese Patent Application Publication No. 2012-112851 Japanese Patent Application Publication No. 2012-21918

C. B. Scruby and L. E. Drain, Laser Ultrasonic: Techniques and Applications (Adam Hilger, Bristol, 1990).

The problem to be solved by the present invention is to provide an ultrasonic inspection technique that can improve the measurement accuracy and measurement speed of ultrasonic inspection for quality assurance of welded parts.

An ultrasonic inspection apparatus according to an embodiment of the present invention includes at least two base materials joined to each other by welding, and for generating ultrasonic waves by irradiating a measurement object having a welded joint construction part. a transmitting light source that oscillates a transmitting laser beam; a receiving light source that oscillates a receiving laser beam that irradiates the measuring object to perform measurement with the ultrasonic wave; and a receiving laser beam that radiates the receiving laser beam to the measuring object. An interference measurement unit that extracts an ultrasonic signal by interferometrically measuring the return light reflected when irradiated, and an evaluation unit that evaluates the shape and size of the bonded portion based on the ultrasonic signal. , at least one of the respective irradiation areas irradiated with the transmitting laser light and the receiving laser light is expanded to include the boundary between the base material and the joining construction part, and the evaluation unit is configured to By measuring transmitted ultrasonic waves or reflected ultrasonic waves using a receiving light source and the interference measurement unit and analyzing the intensity, the actual bonding area, which is the size of the bonding area, is estimated, and the bonding area is estimated. The shape of the part is estimated, and it is evaluated whether the joined part is sound or not.

Embodiments of the present invention provide an ultrasonic inspection technique that can improve measurement accuracy and measurement speed of ultrasonic inspection for quality assurance of welded parts.

FIG. 1 is a configuration diagram showing an ultrasonic testing apparatus according to a first embodiment. FIG. 3 is a block diagram showing a control computer. FIG. 3 is a cross-sectional view showing how incident ultrasound waves and transmitted ultrasound waves are transmitted. FIG. 3 is a cross-sectional view showing how reflected ultrasound waves are transmitted. Flowchart showing ultrasonic inspection processing. FIG. 7 is a perspective view showing a laser beam irradiation mode of Modification 1. FIG. 7 is a cross-sectional view showing a laser beam irradiation mode of Modification 2. FIG. 7 is a cross-sectional view showing a laser beam irradiation mode of Modification 3. FIG. 2 is a configuration diagram showing an ultrasonic testing apparatus according to a second embodiment. FIG. 7 is a configuration diagram showing an ultrasonic testing apparatus according to a third embodiment.

(First embodiment)
Hereinafter, embodiments of an ultrasonic inspection apparatus and an ultrasonic inspection method will be described in detail with reference to the drawings. First, a first embodiment will be described using FIGS. 1 to 5.

Reference numeral 1 in FIG. 1 is an ultrasonic inspection apparatus according to the first embodiment. This ultrasonic inspection apparatus 1 inspects a welded part using a laser ultrasonic method. Spot welding is an example of welding that is subject to inspection. Note that this ultrasonic inspection device 1 can be used not only for spot welding but also for inspection of other welding such as gas welding, arc welding, laser welding, electron beam welding, and friction stir welding.

An example of the measurement object 2 for ultrasonic testing is a metal material in which two plate-shaped base materials 3 are joined to each other by spot welding and have a welded joint 4. The joining portion 4 is a portion where a portion of the base material 3 is once melted when the base material 3 is welded, and then hardened again after welding. This joint construction part 4 is a part of the base material 3, but in the following explanation, in order to facilitate understanding, the once melted part of the base material 3 will be referred to as the joint construction part 4, and the melted part of the base material 3 will be referred to as the joint construction part 4. I will explain it separately from the parts that are not included. In addition, the part where this joining construction part 4 (melted part) and the base material 3 (unmelted part) are in contact will be called a boundary 5.

In addition, dents 6 are formed on the surface of each base material 3, which are depressions caused by spot welding.

The ultrasonic inspection apparatus 1 includes a transmitting light source 10, a receiving light source 11, an interference measuring section 12, a transmitting incidence section 13, a receiving incidence section 14, a transmitting and emitting section 15, a receiving and emitting section 16, a transmitting and transmitting section 17, and a receiving and transmitting section. 18, a return light transmission section 19, and a control computer 20.

The transmission light source 10 is a device that oscillates a transmission laser beam Lt for irradiating the measurement object 2 to generate an ultrasonic wave Ui.

The receiving light source 11 is a device that oscillates a receiving laser beam Lr to irradiate the measurement object 2 and perform measurement using an ultrasonic wave Ur (FIG. 4).

The types of lasers used in the transmitting light source 10 and the receiving light source 11 include, for example, Nd:YAG laser, CO2 laser, Er:YAG laser, titanium sapphire laser, alexandrite laser, ruby laser, dye laser, excimer laser, etc. can be mentioned. Of course, other lasers are also possible.

Furthermore, the lasers used in the transmitting light source 10 and the receiving light source 11 are either continuous waves or pulsed waves. Each of the transmitting light source 10 and the receiving light source 11 may be composed of not only one unit but also two or more units. For example, when each of the transmitting light source 10 and the receiving light source 11 is configured with a plurality of units, the number of other functions required to measure the ultrasonic waves Ui and Ur will also be plural as required.

The interference measurement unit 12 is a device that performs interference measurement on the return light that is reflected when the measurement object 2 is irradiated with the receiving laser beam Lr to extract an ultrasonic signal.

Examples of the interference measurement unit 12 include a Michelson interferometer, a homodyne interferometer, a heterodyne interferometer, a Fizeau interferometer, a Mach-Zehnder interferometer, a Fabry-Perot interferometer, and a photorefractive interferometer. Of course, other laser interferometers are also possible. Furthermore, a knife edge method is also considered as a method other than interference measurement. Any of the interferometers may be used in two or more units.

The transmission laser beam Lt emitted from the transmission light source 10 is incident on the transmission incidence section 13 and is transmitted to the transmission emission section 15 by the transmission transmission section 17 . The transmitting laser beam Lt is emitted from the transmitting emitter 15 and irradiated onto the measurement object 2.

The reception laser beam Lr emitted from the reception light source 11 is incident on the reception incidence section 14 and is transmitted to the reception and emission section 16 by the reception transmission section 18 . The receiving laser beam Lr is emitted from this receiving/emitting section 16 and is irradiated onto the measurement object 2 .

Further, the return light reflected from the measurement object 2 is received by the reception/emission section 16 and transmitted to the interference measurement section 12 by the return light transmission section 19 .

The transmission transmission section 17, the reception transmission section 18, and the return light transmission section 19 are composed of predetermined optical devices such as optical fibers, lenses, mirrors, and prisms that transmit light.

Note that the transmission entrance section 13 and the transmission emission section 15 may be equipped with a uniformization section (not shown) that can uniformize the beam profiles of the laser beams Lt and Lr, if necessary. Furthermore, the transmission entrance section 13 and the transmission emission section 15 may be equipped with a spot diameter adjustment section (not shown) that controls the spot diameters Dt and Dr (FIG. 3) of the laser beams Lt and Lr.

Note that the uniformizing section (not shown) and the spot diameter adjusting section (not shown) are composed of predetermined optical devices such as optical fibers, lenses, mirrors, and prisms that transmit light. In addition to these, the spot diameter adjustment section may be a combination of a fine adjustment mechanism such as a microstage that changes the distance between the lenses or between the measurement object 2 and the optical system.

Further, the spot diameters Dt, Dr (FIG. 3) of the laser beams Lt, Lr adjusted by the spot diameter adjustment section may be circular, elliptical, or quadrangular. An optical device for obtaining a predetermined spot shape, such as a cylindrical lens or an aspherical lens, may be used as the objective lens.

This spot diameter adjustment section serves as an enlarging optical device for enlarging the laser beams Lt and Lr. In this way, without scanning the laser beams Lt and Lr, it is possible to enlarge the laser beams Lt and Lr using an optical magnifying device such as a lens or mirror to extend the irradiation area. This enlarging optical device is a mechanism for adjusting at least the spot diameters Dt, Dr (FIG. 3) of the laser beams Lt, Lr. Note that the enlarging optical device may be a mechanism that changes the shape of the irradiation area of the laser beams Lt and Lr in plan view.

Furthermore, by passing the multimode fiber through the uniformizing section, it can be expected that the profiles of the laser beams Lt and Lr will become uniform as a result. Further, a homogenizer may be used as necessary. Further, the uniformizing section may be composed of an aspherical lens, an array lens, or the like.

The control computer 20 is connected to a transmitting light source 10 , a receiving light source 11 , an interference measuring section 12 , a transmitting input section 13 , a receiving input section 14 , a transmitting and emitting section 15 , and a receiving and emitting section 16 . The control computer 20 controls these devices.

Next, the system configuration of the control computer 20 will be explained with reference to the block diagram shown in FIG. 2. Note that the configuration of the control computer 20 shown in FIG. 2 is an example, and each function may be divided into separate devices or may be integrated. The operation of the ultrasonic testing apparatus 1 is basically performed using the control computer 20, but each device of the ultrasonic testing apparatus 1 may be provided with a separate operating section and operated individually.

The control computer 20 has hardware resources such as a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and HDD (Hard Disk Drive), and the CPU executes various programs. It consists of a computer in which information processing by software is realized using hardware resources. Furthermore, the ultrasonic inspection method of this embodiment is realized by causing a computer to execute various programs.

Note that each component of the control computer 20 does not necessarily need to be provided in one computer. For example, the configuration of one control computer 20 may be realized by multiple computers connected to each other via a network.

The control computer 20 includes an input section 21 , an output section 22 , a communication section 23 , a storage section 24 , a device connection section 25 , and a processing circuit 26 .

The input unit 21 inputs predetermined information. Predetermined information is input to this input unit 21 in response to an operation by a user using the control computer 20. This input unit 21 includes an input device such as a mouse or a keyboard. That is, predetermined information is input to the input unit 21 in response to operations on these input devices.

The output unit 22 outputs predetermined information. For example, the output unit 22 is a display. That is, the control computer 20 includes a device that displays images, such as a display that outputs analysis results and evaluation results. Note that the display may be separate from the computer main body or may be integrated with it.

Note that in this embodiment, a display is exemplified as a device for displaying images, but other modes may be used. For example, a printer that prints information on a paper medium may be used in place of the display.

The communication unit 23 communicates with other computers via communication lines such as the Internet. Note that in this embodiment, the control computer 20 and other computers are connected to each other via the Internet, but other embodiments may be used. For example, the control computer 20 and another computer may be connected to each other via a LAN (Local Area Network), a WAN (Wide Area Network), or a mobile communication network.

The storage unit 24 stores various information necessary when performing an ultrasonic examination. For example, the storage unit 24 stores various programs executed by the processing circuit 26 during the ultrasonic examination, threshold values necessary for determination, evaluation results obtained in the ultrasonic examination, and the like.

Various devices included in the ultrasonic testing apparatus 1 are connected to the device connection section 25 . For example, the transmitting light source 10 , the receiving light source 11 , the interference measuring section 12 , the transmitting incidence section 13 , the receiving incidence section 14 , the transmitting and emitting section 15 , and the receiving and emitting section 16 are connected to the device connecting section 25 . The control computer 20 controls various devices and sends and receives information via the device connection section 25 . That is, the control computer 20 controls the entire ultrasonic testing apparatus 1 . Note that the connection between this device connection section 25 and various devices may be a wired connection or a wireless connection.

The processing circuit 26 of this embodiment is, for example, a circuit including a CPU, a dedicated processor, or a general-purpose processor. This processor implements various functions by executing various programs stored in the storage unit 24. Furthermore, the processing circuit 26 may be configured with hardware such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). Various functions can also be realized by these hardware. Further, the processing circuit 26 can also realize various functions by combining software processing using a processor and a program, and hardware processing.

Further, the processing circuit 26 includes an irradiation area control section 27, an analysis section 28, an evaluation section 29, and a warning control section 30. These are realized by the CPU executing programs stored in the memory or HDD.

The irradiation area control unit 27 controls the irradiation area so that at least one of the irradiation areas irradiated with the transmitting laser beam Lt and the receiving laser beam Lr includes the boundary 5 between the base material 3 and the joining part 4 in plan view. Extend control.

The analysis unit 28 analyzes the intensity and frequency of the ultrasonic wave Ur from the ultrasonic signal obtained by the interference measurement unit 12. Note that part or all of the analysis results of the analysis section 28 may be outputted by the output section 22.

The analysis section 28 has a recording function of the ultrasonic signal obtained by the interference measurement section 12, the intensity of the returned light, and the positional relationship between the measurement object 2 and the irradiation positions of the laser beams Lt and Lr. Furthermore, the analysis unit 28 has signal processing functions such as intensity extraction of ultrasonic signals, frequency analysis, filtering, and averaging.

The evaluation section 29 evaluates the shape and size of the joint construction section 4 based on the analysis results of the analysis section 28. Note that part or all of the evaluation results of the evaluation section 29 may be outputted by the output section 22.

The evaluation section 29 has a function of outputting, from the analysis results obtained by the analysis section 28, those that meet a predetermined standard as passed, and those that do not meet a predetermined standard as rejected. Note that the predetermined standard is based on the strength of the ultrasound signal, and the strength includes not only raw signals but also those processed by signal processing such as filtering and frequency analysis.

The warning control unit 30 controls the output unit 22 to output a predetermined warning when it is determined that there is an abnormality in the joining construction unit 4 based on the analysis result of the analysis unit 28 or the evaluation result of the evaluation unit 29. conduct.

The output unit 22 has a function of displaying part or all of the results processed by the analysis unit 28 and the evaluation unit 29. The output unit 22 may be a general PC display, a television screen, or the like, but it may also be a touch panel or other device with an input function, if necessary. Furthermore, the output unit 22 may be configured by combining a plurality of these or several types. Furthermore, an alarm mechanism capable of issuing a warning may be added as necessary. This warning may be displayed as an image on a display, may be emitted by a lamp, or may be a warning sound output from a speaker. For example, the output unit 22 may be a patrol light (registered trademark), a siren, or a combination thereof.

As shown in FIG. 3, in the first embodiment, both the spot diameter Dt, which is the irradiation area of the transmission laser beam Lt, and the spot diameter Dr, which is the irradiation area of the reception laser beam Lr, are It is expanded to include the boundary 5 between the material 3 and the joint construction part 4. That is, the spot diameters Dt and Dr are expanded so as to be equal to or larger than the size Cf of the uneven portion (construction surface portion) produced on the surface of the measurement object 2 by welding.

Here, in the case of spot welding, the size Cf of the uneven portion is the diameter of the dent 6 (dot point) at the time of spot welding. In the case of butt welding or uranami welding, the size Cf of the uneven portion is the width of the bead.

Here, the size Cw such as the diameter and width of the joining portion 4 is smaller than the size Cf of the dent 6 in most cases. Therefore, if the spot diameters Dt, Dr are expanded so as to be larger than the size Cf of the dents 6, the boundary 5 between the base material 3 and the joint construction part 4 will be included in the range of the spot diameters Dt, Dr. You will be able to do it.

Note that either the spot diameter Dt of the transmitting laser beam Lt or the spot diameter Dr of the receiving laser beam Lr may be smaller than the size Cf of the uneven portion.

Further, either the spot diameter Dt of the transmitting laser beam Lt or the spot diameter Dr of the receiving laser beam Lr may be expanded.

The transmission laser beam Lt emitted from the transmission emission section 15 is irradiated onto the surface of the measurement object 2. Here, an incident ultrasonic wave Ui is generated due to thermal strain or a reaction force caused by ablation of the surface layer. At this time, the spot diameter Dt of the transmitting laser beam Lt is adjusted from approximately φ0.1 mm to the size Cf of the dent 6 or more by a spot diameter adjusting unit (not shown) mounted on the transmitting input section 13 or the transmitting output section 15. Adjusted within the range.

This spot diameter adjustment section consists of several optical devices such as lenses and mirrors. By changing the distance between these parts and the distance to the measurement object 2, the spot diameter Dt can be adjusted. Further, by combining a cylindrical lens and an aspherical lens, a spot other than a circle can be formed, so that the generated incident ultrasonic wave Ui can be given arbitrary directivity, if necessary.

Note that if the transmission entrance section 13 or the transmission exit section 15 is equipped with an equalization section (not shown), the energy distribution of the transmission laser beam Lt over the entire spot diameter Dt becomes uniform, and stable incident superposition is achieved. Transmission of the sound wave Ui becomes possible.

Here, various modes such as longitudinal waves, transverse waves, and surface waves are excited in the incident ultrasonic wave Ui, but waves of any mode are collectively referred to as the incident ultrasonic wave Ui. This incident ultrasonic wave Ui propagates through one of the base materials 3 irradiated with the transmitting laser beam Lt, and reaches the joining section 4 . Here, the ultrasonic wave passes through the portion where the base materials 3 are joined to the other base material 3 that is not irradiated with the transmitting laser beam Lt. This transmitted ultrasonic wave is referred to as a transmitted ultrasonic wave Ut. This transmitted ultrasonic wave Ut is also assumed to have various modes, but waves in any mode are collectively referred to as the transmitted ultrasonic wave Ut.

As shown in FIG. 4, the transmitted ultrasonic wave Ut passes through the joining construction part 4, and reflection of the ultrasonic wave occurs from the end of the other base material 3. The generated reflected waves are referred to as reflected ultrasonic waves Ur. This reflected ultrasonic wave Ur is also assumed to have various modes, but waves in any mode are collectively referred to as reflected ultrasonic wave Ur.

The incident ultrasonic wave Ui, the transmitted ultrasonic wave Ut, and the reflected ultrasonic wave Ur follow the propagation path in the opposite direction, and finally reach the surface of the base material 3 that was first irradiated with the transmitting laser beam Lt. do. Here, the total amount of energy of the transmitted ultrasonic wave Ut and the reflected ultrasonic wave Ur changes depending on the actual bonding area Ja (not shown), which is the area of the bonding part 4 through which the ultrasonic waves have passed. That is, the transmitted ultrasonic wave Ut and the reflected ultrasonic wave Ur have sufficient intensity if the actual bonding area Ja is large, but the intensity decreases if the actual bonding area Ja is small. It is also assumed that the frequency components that each pass through will also change. Therefore, the actual bonding area Ja can be estimated by measuring the transmitted ultrasonic wave Ut or the reflected ultrasonic wave Ur and analyzing its intensity. Furthermore, the shape of the joint construction part 4 can be estimated.

A reception light source 11 and an interference measurement unit 12 are used to measure the transmitted ultrasound Ut and the reflected ultrasound Ur (FIG. 1). For example, the receiving laser beam Lr emitted from the receiving and emitting section 16 is irradiated onto the surface of the measurement object 2. At this time, the spot diameter Dr of the reception laser beam Lr is adjusted from approximately φ0.1 mm to the size Cf of the dent 6 or more by a spot diameter adjustment section (not shown) mounted on the reception entrance section 14 or the reception output section 16. Adjusted within the range.

This spot diameter adjustment section consists of several optical devices such as lenses and mirrors. By changing the distance between these parts and the distance to the measurement object 2, the spot diameter Dr can be adjusted.

The irradiated reception laser beam Lr is reflected by the surface of the measurement object 2. Here, if the surface of the measurement object 2 is vibrating under the influence of the incident ultrasonic wave Ui, the transmitted ultrasonic wave Ut, and the reflected ultrasonic wave Ur, then the ultrasonic wave affected by amplitude modulation, phase modulation, change in reflection angle, etc. The returned light contains sound wave signal components. This return light is again collected by the reception/emission section 16, passes through the return light transmission section 19, and is transmitted to the interference measurement section 12.

The returned light is interferometrically measured by the interferometric measuring section 12, and a voltage signal whose amplitude changes depending on the waveform of the ultrasonic wave Ur is obtained. This voltage signal is recorded as an ultrasonic signal by the analysis section 28 of the control computer 20. The analysis unit 28 can also perform averaging processing, moving average, filtering, fast Fourier transform (FFT), wavelet transform, and other types of signal processing on the obtained ultrasound signal. be.

The evaluation unit 29 of the control computer 20 evaluates the signal strength of the ultrasonic signal with respect to the actual bonding area Ja (not shown). Here, the evaluation section 29 determines whether or not this signal strength satisfies a predetermined reference strength, and evaluates whether or not the joint construction section 4 is sound.

The warning control unit 30 of the control computer 20 has a function of notifying the user that an evaluation result that does not meet predetermined standards has been obtained by displaying on the screen, outputting a warning sound, emitting light, or the like.

Note that the control computer 20 has a function of controlling all or part of the system configuration described in the first embodiment. Note that the control computer 20 can control various devices from a remote location via a LAN or the like. At this time, the content output by the output unit 22, for example, the output of a warning, can be referenced by the user at a remote location.

Next, the ultrasonic inspection process executed by the control computer 20 will be explained using the flowchart of FIG. Note that the above-mentioned drawings will be referred to as appropriate. The following steps are at least some included in the ultrasonic inspection process, and other steps may be included in the ultrasonic inspection process.

First, in step S1, the control computer 20 (FIG. 1) controls the transmission light source 10 to start oscillating the transmission laser beam Lt. Here, the irradiation area control unit 27 (FIG. 2) controls a spot diameter adjustment unit (not shown) to adjust the spot diameter Dt (irradiation area) of the transmitting laser beam Lt for bonding to the base material 3 in plan view. It is expanded to include the boundary 5 of the construction section 4 (Fig. 3).

In the next step S2, the control computer 20 (FIG. 1) controls the reception light source 11 to start oscillating the reception laser beam Lr. Here, the irradiation area control unit 27 (FIG. 2) controls a spot diameter adjustment unit (not shown) to adjust the spot diameter Dr (irradiation area) of the reception laser beam Lr to the base material 3 in a plan view. It is expanded to include the boundary 5 of the construction section 4 (Fig. 3).

Note that the irradiation area control unit 27 expands the irradiation area of the transmitting laser beam Lt and the receiving laser beam Lr to be larger than the area (range) where the joining construction unit 4 is predicted (estimated) to be present. . Note that the entire area where the joint construction part 4 is present does not have to be included in the irradiation area, and at least a part of the area where the joint construction part 4 is present is included in the irradiation area, and the boundary 5 is included in the irradiation area. All you have to do is stay there.

In the next step S3, the control computer 20 (FIG. 1) controls the interference measurement section 12 to start receiving the returned light.

In the next step S4, the interference measurement unit 12 (FIG. 1) performs interference measurement on the return light reflected when the measurement object 2 is irradiated with the receiving laser beam Lr, and extracts an ultrasonic signal. The extracted ultrasonic signals are sent to the control computer 20.

In the next step S5, the analysis section 28 (FIG. 2) of the control computer 20 analyzes the intensity and frequency of the ultrasonic wave Ur from the ultrasonic signal obtained by the interference measurement section 12.

In the next step S6, the evaluation section 29 (FIG. 2) of the control computer 20 evaluates the shape and size of the joint construction section 4 from the analysis result of the analysis section 28.

In the next step S7, the output section 22 (FIG. 2) of the control computer 20 outputs at least one of the analysis result of the analysis section 28 or the evaluation result of the evaluation section 29. For example, a display displays these results.

Note that a part or all of the results of each of the analysis section 28 and the evaluation section 29 are displayed on the display, but the presence or absence of these displays may be switched as appropriate. Further, information such as intensity conditions used for evaluation, outputs of the irradiated laser beams Lt and Lr, and spot diameters Dt and Dr (FIG. 3) can also be displayed on the display.

In the next step S8, the warning control section 30 (FIG. 2) of the control computer 20 determines whether or not there is an abnormality in the joining construction section 4 based on the analysis result of the analysis section 28 or the evaluation result of the evaluation section 29. judge. Here, if there is no abnormality in the joining construction section 4 (NO in step S8), the control computer 20 ends the ultrasonic inspection process. On the other hand, if there is an abnormality in the joining construction section 4 (YES in step S8), the process advances to step S9.

In step S9, the warning control unit 30 controls the output unit 22 to output a predetermined warning. Then, the control computer 20 ends the ultrasonic inspection process.

Note that although the flowchart of this embodiment shows an example in which each step is executed in series, the sequential relationship of each step is not necessarily fixed, and even if the sequential relationship of some steps is swapped. good. Also, some steps may be executed in parallel with other steps.

In the first embodiment, by expanding the irradiation area of the laser beams Lt and Lr, it is possible to achieve both measurement accuracy and speed and to guarantee the quality of welding.

Next, Modification 1 will be explained using FIG. 6. Incidentally, with appropriate reference to the above-mentioned drawings, the same reference numerals are given to the same constituent parts as those shown in the above-described embodiment, and redundant explanation will be omitted.

In modification 1, the irradiation area of one of the transmitting laser beam Lt and the receiving laser beam Lr is an unexpanded dot-shaped irradiation spot P, and the ultrasonic inspection apparatus 1 moves this irradiation spot P. A scanning section 40 is provided for scanning.

For example, as shown in FIG. 6, a scanning section 40 is provided in the reception/emission section 16. The receiving laser beam Lr is emitted from the receiving and emitting unit 16, and the portion irradiated onto the measurement object 2 is an irradiation spot P. The irradiation position of the irradiation spot P is moved by the scanning unit 40. In this modification 1, the irradiation spot P is irradiated to the range where the joining construction part 4 is present.

To explain in more detail, the transmitting laser beam Lt is irradiated onto the measurement object 2 such that the spot diameter Dt of the transmitting laser beam Lt is equal to or larger than the diameter of the size Cf of the dent 6. Here, the receiving laser beam Lr is irradiated onto the measurement object 2 as an irradiation spot P with a diameter of about 0.1 mm. Then, the scanning unit 40 sequentially irradiates the irradiation spots P of the receiving laser beam Lr in a two-dimensional grid pattern.

The scanning unit 40 is assumed to scan the irradiation spot P by a method of mechanically adjusting the angle of an optical mirror such as a galvano scanner. Further, the scanning unit 40 may be a combination of a drive stage.

Note that it is also possible to extend and irradiate the receiving laser beam Lr, make the transmitting laser beam Lt into a dot (irradiation spot P), and scan it with the scanning unit 40.

Further, in the case of Modification 1, the size Cw (FIG. 3) such as the diameter and width of the joining portion 4 can be determined from the ultrasonic signal obtained at each irradiation spot P of the receiving laser beam Lr. Furthermore, it is also possible to predetermine a standard strength for passing the size Cw and perform a pass/fail determination. Furthermore, these pass/fail results can be displayed, recorded, and recalled as a history.

In modification example 1, various parts of the measurement object 2 are irradiated with the laser beams Lt and Lr while the irradiation spot P is moved by the scanning unit 40, so that information such as the shape of the joint construction part 4 can be obtained. Become.

Next, modification 2 will be explained using FIG. 7. Incidentally, with appropriate reference to the above-mentioned drawings, the same reference numerals are given to the same constituent parts as those shown in the above-described embodiment, and redundant explanation will be omitted.

In Modified Example 2, the transmitting laser beam Lt and the receiving laser beam Lr are irradiated to positions facing each other with the bonding section 4 interposed therebetween.

As shown in FIG. 7, the transmitting and emitting section 15 and the receiving and emitting section 16 are provided at opposing positions with the measurement object 2 in between. Then, one surface of the measurement object 2 is irradiated with the transmission laser beam Lt from the transmission emission section 15 . Furthermore, the receiving laser beam Lr is irradiated onto the other surface of the measurement object 2 from the receiving and emitting section 16 . Thereby, only the transmitted ultrasonic wave Ut can be measured.

In the second modification, the size of the joint construction section 4 can be evaluated only by the transmitted ultrasonic wave Ut that has passed through the joint construction section 4, so that measurement accuracy and measurement speed can be improved.

Next, modification 3 will be explained using FIG. 8. Incidentally, with appropriate reference to the above-mentioned drawings, the same reference numerals are given to the same constituent parts as those shown in the above-described embodiment, and redundant explanation will be omitted.

In the above-described embodiment, the case of spot welding is illustrated, but the object to be inspected by the ultrasonic inspection apparatus 1 may also be a joined part 4 welded by a method other than spot welding.

For example, as shown in FIG. 8, the ends of two base materials 3A may be welded together using Uranami welding as the measurement object 2A. This Uranami welding is, for example, a construction in which welding is performed from the outside of the pipe toward the inside, and the joint construction portion 4, which is a weld bead, protrudes also from the inside of the base material 3A. However, since the weld bead that appears on the back side of the base material 3A is located inside the pipe, it is difficult to grasp its shape. Here, with the ultrasonic inspection apparatus 1 of this embodiment, the shape of the weld bead on the back side of the base material 3A can be grasped using the ultrasonic waves Ui and Ut, so the quality of the construction of Uranami welding can be improved. Useful for collateral.

(Second embodiment)
Next, a second embodiment will be described using FIG. 9. Incidentally, with appropriate reference to the above-mentioned drawings, the same reference numerals are given to the same constituent parts as those shown in the above-described embodiment, and redundant explanation will be omitted.

The ultrasonic inspection apparatus 1A of the second embodiment includes a surface reading section 50 in addition to the configuration of the first embodiment described above. This surface reading section 50 is connected to the control computer 20.

The surface reading unit 50 is a device that reads the range of the uneven portion formed on the surface of the measurement object 2 by welding, before the measurement object 2 is irradiated with the transmission laser beam Lt and the reception laser beam Lr.

The irradiation area control unit 27 (FIG. 2) of the control computer 20 of the second embodiment also controls the spot diameters Dt and Dr (FIG. 3) of at least one of the transmitting laser beam Lt and the receiving laser beam Lr on the surface. Control is performed to make the range larger than the range read by the reading unit 50. In this way, the uneven portion (for example, the dents 6) generated on the surface of the measurement object 2 can be used as a reference for estimating the range of the joining portion 4. Then, based on this criterion, the spot diameters Dt and Dr of the transmitting laser beam Lt and the receiving laser beam Lr can be expanded to include the boundary 5 between the joining part 4 and the base material 3.

Here, the surface reading section 50 is configured with devices such as a camera, a stereo camera, and a pattern type laser. Note that the surface reading section 50 may be configured by a plurality of these devices or a combination of these devices. At this time, a shutter or the like may be provided in the front surface reading section 50 so that the transmitting laser beam Lt or the receiving laser beam Lr does not enter as stray light.

The step of reading the surface of the measurement object 2 by the surface reading section 50 is basically provided before step S1 in the above-mentioned flowchart (FIG. 5), but in some cases, it may be provided after step S1 or after step S1. It may be executed simultaneously with S1.

The surface reading unit 50 estimates the size Cf of the uneven portion formed on the surface of the measurement object 2. The estimation method may be one that performs threshold processing by pattern extraction from the camera image obtained by the surface reading unit 50, or may be a three-dimensional shape measurement using a combination of a stereo camera and a laser pattern.

The reading result of the surface of the measurement object 2 obtained by the surface reading section 50 is sent to the evaluation section 29 (FIG. 2) of the control computer 20. Based on this reading result, if the size Cf of the uneven portion is within the specified manufacturing range, it will be judged as first pass; if it is larger or smaller than that, it will be judged as first pass, and the judgment result will be displayed on the display ( The information is displayed on the output section 22), etc. In addition, if it is possible to measure not only the size Cf of the uneven portion but also the degree of surface unevenness, that value may also be displayed on the display, or if a standard surface roughness is provided, The standard may be used for pass/fail determination.

In the second embodiment, when irradiating the transmitting laser beam Lt and the receiving laser beam Lr, it is possible to perform irradiation according to the state of the surface of the measurement object 2. In addition, it becomes possible to predict the range in which the joint construction part 4 is located, and at least one of the respective irradiation areas irradiated with the transmitting laser light Lt and the reception laser light Lr is set to the boundary between the base material 3 and the joint construction part 4. It can be expanded to include 5.

(Third embodiment)
Next, a third embodiment will be described using FIG. 10. Incidentally, with appropriate reference to the above-mentioned drawings, the same reference numerals are given to the same constituent parts as those shown in the above-described embodiment, and redundant explanation will be omitted.

The ultrasonic inspection apparatus 1B of the third embodiment includes a surface modification section 60 and an oxidation suppression section 61 in addition to the configuration of the first embodiment described above. These surface modification section 60 and oxidation suppression section 61 are connected to the control computer 20. In addition, the ultrasonic inspection apparatus 1B may be configured to include either the surface modification section 60 or the oxidation suppression section 61.

The surface modification unit 60 is a device that homogenizes the surface of the measurement object 2 that is irradiated with the transmitting laser beam Lt and the receiving laser beam Lr.

For example, the surface modification unit 60 may be a cutting mechanism such as a grinder or a wire brush for grinding the surface of the measurement object 2. Further, the surface modification unit 60 may be a shot blast type processing mechanism such as laser, sandblasting, or dry ice blasting that can process the surface of the measurement object 2 in a non-contact manner using a predetermined medium 62. Further, the surface modification unit 60 may be a mechanism for applying high temperature resistant ink, paint, or a thin metal film to the surface of the measurement object 2.

Here, the material applied to the surface of the measurement object 2 is a material that can withstand grinding by other grinding devices, can withstand high temperatures, and can be ablated by the transmitting laser beam Lt, or a material that is compatible with the wavelength of the receiving laser beam Lr. On the other hand, a coating material with a high reflectance may be used. Note that this coating material is not only applied by the surface modification section 60, but also may be applied by an inspector or a welding worker before or during the inspection.

The modification of the surface of the measurement object 2 by the surface modification section 60 may be performed on at least one of the irradiation areas of the transmitting laser beam Lt and the receiving laser beam Lr. Here, it is necessary to modify the surface of the measurement object 2 before transmitting and receiving ultrasonic waves.

The oxidation suppressing unit 61 is a device that suppresses oxidation of the surface of the measurement object 2 by covering at least one of the respective irradiation areas irradiated with the transmitting laser beam Lt and the receiving laser beam Lr with an atmosphere of an inert gas 63. be.

For example, the oxidation suppressing unit 61 is a mechanism that sprays an inert gas 63 onto a surface that is irradiated with the transmitting laser beam Lt and the receiving laser beam Lr. In order to efficiently fill the blown inert gas 63, the measurement object 2 may be provided in a simple chamber.

The inert gas 63 used here may be commonly used rare gases such as helium, neon, and argon, nitrogen, or any other chemically stable gas.

In addition, although FIG. 10 illustrates a form in which irradiation is applied to one side of the measurement object 2, the surface modification section 60 and the oxidation suppression section 61 may be arranged on both sides sandwiching the measurement object 2. In this way, it becomes possible to cope with a mode in which the transmitting laser light Lt and the receiving laser light Lr are respectively irradiated onto both the front and back surfaces of the measurement object 2.

In the third embodiment, by providing the surface modification portion 60, the surface of the measurement target 2 becomes constant regardless of individual differences. Therefore, the excitation of the ultrasonic wave Ui on the surface of the measurement object 2 and the reflection of the returned light are performed under constant conditions, and the transmission and reception efficiency of the ultrasonic wave Ui can be improved.

Further, it is known that the transmission and reception efficiency of the ultrasonic waves Ui and Ur differs depending on the surface roughness and color on both the transmitting side and the receiving side of the ultrasonic waves Ui and Ur. In the third embodiment, by providing the surface modification section 60, the color or roughness of the surface of the measurement object 2 is kept constant, which affects the transmission and reception efficiency of the ultrasonic waves Ui and Ur. 2 individual differences can be eliminated. This enables stable measurement regardless of individual differences in the measurement object 2.

Further, by providing the oxidation suppressing section 61, oxidation of the surface of the measurement object 2 can be suppressed, and discoloration or deformation of the surface can be prevented, so that stable measurement can be performed.

In addition, by spraying the inert gas 63 on the surface irradiated with the laser beams Lt and Lr, when the surface of the measurement object 2 momentarily becomes high temperature due to heating by the laser beams Lt and Lr, oxygen in the air It can prevent discoloration and deformation due to oxidation.

Although the ultrasonic inspection apparatuses 1, 1A, 1B and the ultrasonic inspection method are described based on the first embodiment (variations 1 to 3) to the third embodiment, the configuration applied in any of the embodiments is may be applied to other embodiments, or configurations applied in each embodiment may be combined.

The control computer 20 described above includes a control device with highly integrated processors such as FPGA, GPU (Graphics Processing Unit), CPU, and dedicated chips, storage devices such as ROM and RAM, and HDD and SSD (Solid State Drive). A display device such as a display, an input device such as a mouse and a keyboard, and a communication interface. This control computer 20 can be realized with a hardware configuration using a normal computer.

Note that the program executed by the control computer 20 is provided by being pre-installed in a ROM or the like. Additionally or alternatively, this program may be installed as a file in installable or executable format on a computer-readable non-temporary computer such as a CD-ROM, CD-R, memory card, DVD, or floppy disk (FD). It is stored on a storage medium and provided.

Further, the program executed by the control computer 20 may be stored in a computer connected to a network such as the Internet, and may be downloaded and provided via the network. Further, the control computer 20 can also be configured by combining separate modules that independently perform the functions of the constituent elements by interconnecting them via a network or a dedicated line.

According to at least one embodiment described above, at least one of the respective irradiation areas irradiated with the transmitting laser beam Lt and the receiving laser beam Lr includes the boundary 5 between the base material 3 and the joining part 4. The measurement accuracy and speed of ultrasonic inspection for quality assurance of welded parts can be improved.

Although several embodiments of the invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, changes, and combinations can be made without departing from the gist of the invention. These embodiments or modifications thereof are within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

1, 1A, 1B...Ultrasonic inspection device, 2, 2A...Measurement object, 3, 3A...Base material, 4...Joining area, 5...Boundary, 6...Damage, 10...Light source for transmission, 11...For reception Light source, 12... Interference measurement section, 13... Transmission incidence section, 14... Reception incidence section, 15... Transmission emission section, 16... Reception emission section, 17... Transmission transmission section, 18... Reception transmission section, 19... Return light transmission section , 20... Control computer, 21... Input section, 22... Output section, 23... Communication section, 24... Storage section, 25... Equipment connection section, 26... Processing circuit, 27... Irradiation area control section, 28... Analysis section, 29...Evaluation section, 30...Warning control section, 40...Scanning section, 50...Surface reading section, 60...Surface modification section, 61...Oxidation suppression section, 62...Medium, 63...Inert gas.

Claims (9)

a transmitting light source that oscillates a transmitting laser beam for generating ultrasonic waves by irradiating it onto a measurement target having at least two base materials joined to each other by welding and the welded joint construction section;
a reception light source that oscillates a reception laser beam for irradiating the measurement target to perform measurement with the ultrasonic wave;
an interference measurement unit that extracts an ultrasonic signal by interferometrically measuring returned light reflected when the receiving laser beam is irradiated to the measurement target;
an evaluation unit that evaluates the shape and size of the joint construction part based on the ultrasonic signal;
Equipped with
At least one of the respective irradiation areas irradiated with the transmitting laser light and the receiving laser light is expanded to include a boundary between the base material and the joining construction part,
The evaluation unit measures transmitted ultrasound or reflected ultrasound using the reception light source and the interference measurement unit, and analyzes the intensity to determine the actual bonding area, which is the size of the bonding area. estimating the shape of the joint construction part, and evaluating whether the joint construction part is sound.
Ultrasonic inspection equipment. An enlarging optical device for enlarging the transmitting laser light or the receiving laser light is provided on at least one of the respective emission parts that emit the transmitting laser light and the receiving laser light.
The ultrasonic testing device according to claim 1. The transmitting laser light and the receiving laser light are irradiated to opposing positions with the joining construction part in between.
The ultrasonic testing device according to claim 1 or claim 2. Before irradiating the transmitting laser beam and the receiving laser beam, a surface reading unit is provided that reads a range of a portion forming an uneven portion formed on the surface of the measurement target by the welding.
The ultrasonic testing device according to claim 1 or claim 2. comprising an irradiation area control unit that makes a spot diameter of at least one of the transmitting laser beam and the receiving laser beam larger than the range read by the surface reading unit;
The ultrasonic testing device according to claim 4. The irradiation area of one of the transmitting laser beam and the receiving laser beam is an unexpanded irradiation spot, and includes a scanning unit for moving the irradiation spot.
The ultrasonic testing device according to claim 1 or claim 2. comprising a surface modification unit that homogenizes the surface of the measurement target that is irradiated with the transmitting laser light and the receiving laser light;
The ultrasonic testing device according to claim 1 or claim 2. an oxidation suppressing unit that covers at least one of the respective irradiation regions irradiated with the transmitting laser light and the receiving laser light with an inert gas atmosphere and suppresses oxidation of the surface of the measurement target;
The ultrasonic testing device according to claim 1 or claim 2. At least two base materials are joined to each other by welding, and a transmitting light source oscillates a transmitting laser beam for irradiating a measuring object having a welded joint portion to generate an ultrasonic wave. ,
a step in which a receiving light source oscillates a receiving laser beam for irradiating the measurement target to perform measurement with the ultrasonic wave;
an interference measuring unit interferometrically measuring return light reflected when the receiving laser beam is irradiated to the measurement target to extract an ultrasonic signal;
an evaluation unit evaluating the shape and size of the joint construction part based on the ultrasonic signal;
including;
At least one of the respective irradiation areas irradiated with the transmitting laser light and the receiving laser light is expanded to include a boundary between the base material and the joining construction part,
In the evaluating step, the transmitted ultrasound or reflected ultrasound is measured using the receiving light source and the interference measurement unit, and the intensity thereof is analyzed to determine the actual bonding area, which is the size of the bonding area. estimating the shape of the joint construction part, and evaluating whether the joint construction part is sound.
Ultrasonic testing method.

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