JPH0291562A - Ultrasonic flaw detector - Google Patents

Abstract

PURPOSE:To apply detection to a container, tubular object to be inspected, etc., by providing a magnetizing coil by which a magnetic flux is generated in an object to be inspected in the vicinity of the surface irradiated with a laser beam and a detecting coil to detect a current generated by an echo signal coming from the object. CONSTITUTION:When a defect 5 is existed in the object 3, an ultrasonic wave beam 4 is partly reflected and returned as the echo signal 6 to the surface of the object 3. The magnetizing coil 7 is arranged over the surface of the object 3, and the generated magnetic flux 8 is existed around the surface of the object 3. Therefore, the current 10 is made to flow in the neighbourhood of the crossing pint of the echo signal 6 and the magnetic flux 8, while intersecting orthogonally with both of them. The magnetic flux is generated around the place where the current 10 is made to flow, and an induced voltage is generated in the detecting coil 8 due to the magnetic flux is crossed with the detecting coil 9, then by means of detecting this voltage, the echo signal 8 corresponding to the induced voltage can be detected. The detection is thereby applicable for the container and the tubular object to be inspected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a non-contact type ultrasonic flaw detection device, and in particular uses a laser beam for transmission and an electromagnetic ultrasonic contact for reception. The present invention relates to an ultrasonic flaw detection device suitable for performing ultrasonic flaw detection from one side of a probe without contacting the probe.

[Conventional technology]

Conventional devices of this type, as described in Japanese Patent Publication No. 60-36019, scan a laser beam on one surface of the object to transmit an ultrasound beam, and transmit an electromagnetic ultrasound beam on the other surface. The ultrasonic beam was received by scanning the object and detecting flaws in the object.

[Problem to be solved by the invention]

However, the above-mentioned conventional technology takes into account the case where containers and tubular objects can be approached only from the outside, that is, from the ultrasonic beam transmitting side, and the electromagnetic ultrasonic contactor used for detecting echoes. No consideration was given to improving detection ability.

For this reason, there were problems in that it was impossible to detect flaws from only one side of the object, and the detection ability was also insufficient.

The present invention was made based on the above circumstances, and its purpose is to enable a detector to be placed on the beam transmitting side, to be able to target, for example, containers, tubular objects, etc., and to be small in size with high detection capability. An object of the present invention is to provide an ultrasonic flaw detection device that can improve the flaw detection.

[Means to solve the problem]

In order to achieve such an objective, the present invention.

a laser beam generator that irradiates one surface of a subject with a laser beam; a magnetization coil that is arranged around the laser beam and generates a magnetic flux in the subject near the laser beam irradiation surface; and a detection coil that detects a current generated by an echo signal from the subject.

Further, the magnetizing coil has a magnetic core provided in the path of the magnetic flux.

[Effect]

In this way, the object to be inspected and
Excitation coils and detection coils required for flaw detection can be placed. Therefore, even if the object to be inspected is, for example, a cylindrical container, the contents of the object can be detected.

Furthermore, since the excitation coil and the detection coil are arranged around the laser beam, the amount of echo signals extracted by the excitation coil can be increased, and the amount of conversion of the echo signal into an electric signal by the detection coil can be increased. Therefore, the detection ability can be improved.

〔Example〕

Hereinafter, a first embodiment of the ultrasonic flaw detection device according to the present invention will be described.
1! This will be explained using FIGS. 1 to 11.

First, FIG. 1 is a diagram showing a first embodiment of a laser and electromagnetic ultrasonic flaw detection apparatus according to the present invention, which uses a laser beam for transmission and uses an electromagnetic ultrasonic contactor for reception. Here, 1 is a laser beam and 2 is a lens.

3 is the object surface, 4 is the ultrasonic beam inside the object 3, 5 is a defect inside the object 3, 6 is an echo signal inside the object 3, 7 is a magnetizing coil, 8 is a magnetic flux, 9 is a detection coil, 10 is a current generated from the echo signal 6. Here, the magnetization coil 7 and the detection coil 9 are both air-centered and coaxially arranged, and the laser beam 1 is incident along the central axis thereof so that the object 3 is irradiated with the laser beam 1. It has become.

With this configuration, now the pulsed laser beam 1
When the liquid is placed on the three surfaces of the object, the three surfaces of the object are rapidly heated and expand, producing stress waves on the three surfaces of the object. This applied wave becomes an ultrasonic beam 4 and propagates into the subject 3.

If there is a defect 5 within the object 3, a portion of the ultrasound beam 4 is reflected and returns to the surface of the object 3 as an echo signal 6. A magnetization coil 7 is located on the surface of the subject 3 and generates a magnetic flux 8, and the magnetic flux 8 exists near the surface of the subject 3. Therefore, near the intersection of the echo signal 6 and the magnetic flux 8, a current 10 flows perpendicularly to the echo signal 6 and the magnetic flux 8. When the current 10 flows, a magnetic flux (not shown) is generated around this, and this magnetic flux intersects with the detection coil 9, so an induced voltage is generated in the detection coil 8, and by detecting this, it corresponds to this induced voltage. Echo signal 8 can be detected.

FIG. 2 shows a second embodiment of the present invention, which is based on the configuration shown in FIG. 1, in which a cup-shaped magnetic core 11 is provided outside the magnetizing coil 7 and the detection coil 9. This magnetic core 11
By providing this, the amount of magnetic flux 8 can be increased, and detection sensitivity can be improved.

FIG. 3 shows a third embodiment of the present invention, in which the direction of the magnetic flux 14 formed by the magnetizing coil is configured to be parallel to the surface of the object 3. Here, 12 is one magnetization coil, 13 is the other magnetization coil, 14 is a magnetic flux, and 15 is a current. Since the magnetizing coils 12 and 13 are arranged on the left and right sides of the laser beam 1, the direction of the magnetic flux 14 can be changed from the direction of the magnetic flux 8 in FIG. In this way, in FIG. 1, the laser beam 1 is injected near the magnetic flux 8 perpendicular to the 3 surfaces of the object to be examined, whereas in FIG. The laser beam 1 will be injected into the vicinity of . Therefore, the distribution of the current 15 is also different. Therefore, in this embodiment, a current of 1 is applied near the input of the laser beam 1.
5 will start flowing.

FIG. 4 shows a fourth embodiment of the present invention, which is based on the configuration shown in FIG. 3, but in which a U-shaped magnetic core 16 is provided in the magnetic flux 14 path. By providing this magnetic core 16, the magnetic flux 14
can be increased in size, and detection sensitivity can be improved. In this case, the magnetic core 16 is provided with holes 16A through which the laser beam 1 passes, so as not to interfere with the laser beam 1.

FIG. 5 shows a fifth embodiment of the present invention, in which the magnetizing coil 13 is removed from the configuration shown in FIG. 4, leaving only one magnetizing coil 12. It can be miniaturized and the accessibility to the subject 3 can be improved without interfering with other parts (not shown).

FIG. 6 shows a sixth embodiment of the present invention, which corresponds to the configuration shown in FIG. 1 and uses a superconducting magnetizing coil as the magnetizing coil. Here, 20 is a superconducting magnetizing coil made of a high-temperature superconducting material such as yttrium, 21 is a coolant such as liquid nitrogen that cools the superconducting magnetizing coil 2o, and 22 is a cooling material 21-holding material made of a heat insulating material or the like. It is a container. Other signals 1 to 9 use the same members as in FIG. Since the superconducting magnetizing coil 20 is used as the magnetizing coil, a larger magnetic flux 8 can be supplied than when using a normal magnetizing coil, and detection sensitivity can be improved.

FIG. 7 shows a seventh embodiment of the present invention, which is based on the configuration using the superconducting magnetizing coil 20 shown in FIG. 6, and a cup-shaped magnetic core 11 is provided on the outside of the superconducting magnetizing coil 20. This magnetic core 1
1 allows the magnitude of the magnetic flux 8 to be increased.

FIG. 8 shows an eighth embodiment of the present invention, which corresponds to the configuration shown in FIG. 3 and uses a superconducting magnetizing coil as the magnetizing coil. Here, in Figure 1, 23 is one superconducting magnetizing coil, and 23 is one superconducting magnetizing coil.
4 is the other superconducting magnetizing coil, and both coils supply magnetic flux 14.

25.26 is the coolant for the superconducting magnetization coil 23.24, 2
7.28 is a container for holding the coolant 23.24. 6 Other symbols 1 to 9 are the same as in FIG. 3. 23.24 to the superconducting magnetization coil, it is possible to supply a larger magnetic flux 14.

FIG. 9 shows a ninth embodiment of the present invention, which corresponds to the configuration shown in FIG. 4 and uses a superconducting magnetizing coil as the magnetizing coil. That is, a U-shaped magnetic core 16 is provided as shown in FIG. Symbols 1 to 14 and 23 to 28 are the same as in FIG. By providing the magnetic core 11, an even larger magnetic flux 14 can be supplied.

FIG. 10 shows a tenth embodiment of the present invention, which corresponds to the configuration shown in FIG. 5 and uses a superconducting magnetizing coil as the magnetizing coil. Symbols 1 to 27 are the same as in FIG. It is designed to be smaller.

FIG. 11 is an eleventh embodiment of the present invention, and shows the configuration of a typical laser and electromagnetic ultrasonic flaw detection device.
30 is a pulse laser beam generator, 31 is a synchronization circuit, 3
2 is a magnetization power supply device, 33 is a received signal amplifier, 34 is a received signal display device, and 35 is a coolant supply device.

A pulsed laser beam generator 30 generates a laser beam 1 in response to a synchronization signal from a synchronization circuit 32 . Prior to this,
The magnetization power supply device 32 supplies current to the magnetization coils 23 and 24 to magnetize them.

By laser beam 1 applied to 3 surfaces of the object.

Since the three surfaces of the subject are rapidly heated, stress waves are generated due to thermal expansion of the three surfaces of the subject. This stress wave propagates within the object 3 as an ultrasonic beam 4, and returns as an echo signal if there is a discontinuity such as a defect. The echo signal is magnetic flux 14
A current is generated in the subject 3 due to the interaction with the current, and a voltage is induced in the detection coil 9 due to the action of the magnetic flux of this current. Therefore, this induced voltage is amplified by the amplifier 33, and the display device 3
4, it becomes possible to identify defects, etc.

As explained above, this embodiment has the effect of solving many problems such as detection sensitivity, dead zone, directivity, miniaturization, detection method, etc., which were difficult points of conventional non-contact ultrasonic flaw detection methods. . In detail, (1) Detection sensitivity It is possible to improve the detection sensitivity and the S/N ratio by making the pulsed laser beam more powerful and increasing the magnetic flux.

(2) Dead zone Since it is excited with a short pulsed laser beam, it is possible to shorten the dead zone.

(3) Directivity It is possible to change the directivity by changing the size, shape, etc. of the laser beam.

(4) Miniaturization Since the laser beam can be incident point-wise, the detection section can be miniaturized.

(5) Laser and electromagnetic ultrasonic flaw detection methods become possible.

(6) Output waveform Since the vibration caused by the laser beam is detected using the eddy current effect, it can be measured in wt as a waveform.

(7) Mode The stress wave mode during pulse transmission by a laser beam is due to thermal expansion, so it is a simpler mode than the stress wave transmitted by a magnetic field and thin current. 6 (8) To detect structural vibration by electromagnetic method, Signals can be converted using only magnetization and detection coils, resulting in a simple structure.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the detection section can be placed on the beam transmitting side, and can be used to target, for example, containers, tubular objects, etc., and the detection ability can be improved with a small size. It is possible to provide an ultrasonic flaw detection device that can perform

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of an ultrasonic flaw detection device according to the present invention, and FIGS. 2 to 11 are block diagrams showing other embodiments of the ultrasonic flaw detection device according to the present invention. . 1 is a laser beam, 2 is a lens, 4 is an ultrasonic beam, 7
is a magnetizing coil, 8 is a magnetic flux, 9 is a detection coil, 11 is a magnetic core, 12 and 13 are magnetizing coils, 14 is a magnetic flux, 16 is a magnetic core,
20 is a superconducting magnetization coil, 21 is a coolant, 22 is a container,
23.24 is a superconducting magnetizing coil, 25.26 is a coolant,
27 and 28 are containers, 30 is a pulsed laser beam generator, 31 is a synchronous circuit, 32 is a magnetization power supply device, and 33 is an amplifier. 34 is a display device, and 35 is a coolant supply device. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A laser beam generator that irradiates one surface of a subject with a laser beam; a magnetization coil that is arranged around the laser beam and generates magnetic flux in the subject near the laser beam irradiation surface; An ultrasonic flaw detection detection device comprising: a detection coil arranged around the laser beam and detecting a current generated by an echo signal from the object to be inspected. 2. The ultrasonic flaw detection apparatus according to claim 1, wherein a magnetizing coil and a detection coil are provided on the surface of the object to be inspected and are wound in parallel directions, and a laser beam is introduced into the space between these coils. 3. The ultrasonic flaw detection device according to claim 2, wherein a magnetic core is provided in the magnetic flux path. 4. Ultrasonic flaw detection according to claim 1, comprising: a plurality of magnetization coils wound in a plane perpendicular to the surface of the object to be inspected, and a detection coil wound in a direction parallel to the surface. Device. 5. The ultrasonic flaw detection device according to claim 4, wherein a magnetic core is provided in the magnetic flux path. 6. An ultrasonic flaw detection device according to any one of claims 1 to 5, wherein the magnetizing coil is a superconducting magnetizing coil.