JPS629269A - Liquid tank for ultrasonic inspection - Google Patents

Abstract

PURPOSE:To enable the flaw detectionof good accuracy by forming the bottom face of a liquid with the film fixing its periphery of the outer periphery of the liquid tank in the state having the value approximate to the sound inpedance of the liquid inside the liquid tank and having the slack deformable in an optional uneven shape. CONSTITUTION:The bottom face of a liquid tank A is formed by a film 2, for which those which are in extremely thin film thickness, several mu- scores mu, for instance, are used, although it varies according to the size of the liquid tank A and the shape of the flaw detection face of the body 4 to be inspected with which the external face of the film 2 comes in contact. The periphery of the film 2 is fixed to the circumference of the liquid tank A so as to leak no liquid 3 inside the liquid tank A, but in such case, the film 2 is fixed with a slack so that it can be closely fitted by deforming in the optional uneven face shape of the flaw detecting face of the body 4 to be inspected. For the material of the film 2 that which has the same or approximate value as or to the sound impedance of the liquid 3 and yet the strength to bear the tare weight of the liquid 3 in the film thickness is used. And in the liquid tank A an ulrasonic wave is emitted on the flaw detecting face of the body 4 to be inspected which is set outside the liquid tank A by the probe 5 dipped inside the liquid 3 and is received to the probe 5 almost as it is and the flaw detection can be performed with good accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a liquid tank used when testing a specimen using ultrasonic waves. [Background of the Invention] There are various methods for detecting defects in industrial products and materials using ultrasonic waves.
Dimensions 1 Surface roughness, estimated defect position 9 Dimensions, shape 9
They are used differently depending on the type. Among the various flaw detection methods, the most widely used is the pulse reflection method, but these methods are classified into the direct contact method and the immersion method, and each method has its own characteristics and has been popular for a long time. The direct contact method is a method in which flaws are detected by directly contacting the probe to the test surface of the test object through a couplant such as oil, and has the great advantage of being extremely easy to detect flaws in real time. Couplant thickness.

Not only is the efficiency of transmitting and receiving ultrasonic waves fluctuating depending on the type, and the waveform of the reflected wave is fluctuating, but the method of abutting the probe also has the above-mentioned effects. Therefore, in such cases, it is necessary not to require highly accurate flaw detection, or if high accuracy is required, it is necessary to process the flaw detection surface to reduce roughness. A liquid immersion method (usually called a water immersion method because water is usually used as the liquid) is used to overcome these disadvantages of the direct contact method. In addition to the general immersion method, in which the subject and probe are immersed in liquid, there is also a local immersion method, in which only the area between the test part of the subject and the probe is locally filled with liquid. In addition to water, the liquid used to immerse the specimen and probe is oil, freon, or trichlene.

Methanol etc. are used. In the liquid immersion method, since there is no direct contact between the specimen and the probe, ultrasonic waves can be transmitted and received stably, and the drawbacks of the direct contact method have been solved, and the method is widely used for automatic flaw detection.

However, there are many types of objects to be tested, such as electronic parts and precision mechanical parts, that must be protected against liquid intrusion, rust, contamination, etc. The water immersion method.

There is a drawback that it is necessary to remove the adverse effects on the object after the flaw detection, so that it cannot be used as is. For this reason, some liquid immersion methods that use preon or trichlene as liquids have been put into practical use to eliminate the above-mentioned disadvantages of the water immersion method, but these liquids have negative effects such as rusting and contamination on the specimen. However, the attenuation of the ultrasonic waves in the liquid is large and the accuracy of flaw detection is reduced accordingly, which poses a major practical problem.

[Purpose of the invention]

The present invention solves the above-mentioned problems of the conventional technology, and is not affected by the type, shape, dimensions, surface roughness, etc. of the specimen, and prevents liquid from entering the specimen and causing rust.

easily and accurately without any negative effects such as contamination.
Moreover, it is an object of the present invention to provide a liquid tank for ultrasonic inspection that can perform flaw detection in real time.

[Summary of the invention]

The present invention provides a liquid tank for ultrasonic inspection in which the bottom surface of the liquid tank is
It has a value that is the same as or approximates the acoustic impedance of the liquid in the liquid tank, and is formed of a membrane that is fixed to the outer periphery of the liquid tank in a sagging state so that it can be deformed into any uneven surface shape. It is possible to detect flaws by touching the bottom of the liquid tank to the flaw detection surface of a test object placed outside the tank, depending on the type of test object.

This is a liquid tank for ultrasonic testing that allows flaw detection to be performed easily, accurately, and in real time without being affected by shape, dimensions, etc., and without having any adverse effects such as rust on the test object.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to the drawings. 1 is the peripheral wall of the liquid tank A, and its shape and dimensions are similar to that of the object 4 and the probe 5.
It can be arbitrarily determined depending on the type, shape, dimensions, etc. Liquid tank A
The bottom surface of is formed by membrane 2.

[2 indicates the dimensions of the liquid tank A and the specimen 4 to which the outer surface of the membrane 2 comes into contact.
Although it varies depending on the shape and surface roughness of the flaw detection surface, a very thin film with a thickness of, for example, several microns to several tens of microns is used. If the size of the liquid tank A is large, the weight of the liquid 3 in the liquid tank A is large and strength is required to support the weight, so the film thickness is relatively thick, several tens of microns or O.L.
On the other hand, if the dimensions of the liquid tank A are small, the film thickness may be thin in terms of strength. On the other hand, when the surface of the test object 4 has large irregularities, corners are detected, or the surface is rough, even if the film thickness is relatively thick, from several tens of microns to 0.1 am, the shape of the surface However, if the surface roughness is small, the thinner the film, the easier it will be to adapt to the roughness and adhere to the surface. The periphery of the membrane 2 is fixed around the liquid tank A so that the liquid 3 in the liquid tank A does not leak out, but the removed membrane 2 deforms into the arbitrary uneven surface shape of the test surface of the test object 4 and adheres tightly. It is fixed with some slack so that it can be fixed. Therefore, when the liquid 3 is placed in the liquid tank A, the membrane 2 bulges downward by the amount of slack, and in this state, the test surface of the test object 4 is brought into contact with the bulged outer surface of the membrane 2 by pushing it upward. or liquid tank A
When the probe is gently lowered onto the flaw detection surface of the object 4 installed on the outside of the test object 4 and comes into contact with the flaw detection surface, it comes into close contact with the flaw detection surface as shown in FIG. - As shown in the figure, a flange la is provided at the lower end of the peripheral wall 1 to fix the membrane 2 to the liquid tank A, and a stand 7 is provided with an adjuster 6 for adjusting the height of the liquid tank A below the flange la. Although the case where the periphery of the membrane 2 is sandwiched between the membranes 1 and 2 is shown, it may be attached to the inner or outer periphery of the peripheral wall 1. The amount of sagging of the membrane 2 described above is determined as appropriate depending on the size of the unevenness of the test surface of the test object 4. The material of membrane 2 is liquid 3
has a value that is the same as or similar to the acoustic impedance of
In addition, a material having the above-mentioned film thickness and strength enough to withstand the weight of the liquid 3 is used. For example, when the liquid 3 is water, a membrane made of polyethylene neoprene rubber, silicone rubber, etc. is used.

In the liquid tank A having the above-described configuration, when ultrasonic waves are emitted from the probe 5 immersed in the liquid 3 to the test surface of the test object 4 set outside the liquid tank A, the bottom surface of the liquid tank A is formed. This is because the membrane 2 conforms to the shape of the flaw detection surface and is in close contact with it, and the acoustic impedances of the liquid 3 and the membrane 2 are the same or have similar values.

The emitted ultrasonic beam 8 has very little attenuation due to reflection and transmission through the membrane 2, as if the membrane 2 did not exist, and enters the subject 4 as it is, causing reflected waves from the subject 4. Similarly, the signal is received by the probe 5 almost unchanged. This is a state where the specimen 4 is set outside the liquid tank A and is immersed in the liquid 3 for flaw detection.
3. Intrusion of liquid 9. Rust caused by being immersed in the interior.

It completely eliminates the negative effects of contamination and other processing steps to remove the negative effects, and allows highly accurate flaw detection without being affected by surface roughness, like the conventional t-immersion method. In addition, the liquid to be used is usually water, which is the cheapest and easiest to obtain, but it is not limited to water; if you use oil, acetone, alcohol, etc. with a low specific gravity, the thickness of the membrane 2 can be reduced accordingly. be able to.

In addition, when setting the test object 4, it is necessary that its flaw detection surface is in close contact with the membrane 2 as much as possible, so the adjuster 6 provided on the stand 7 is operated to ensure that the weight of the liquid 3 is sufficiently transmitted to the flaw detection surface via the membrane 2. Adjust the height of liquid tank A. Further, in order to promote the close contact between the flaw detection surface and the membrane 2, a coupling material such as water, oil, or glycerin is applied to the flaw detection surface.

The flaw detection method is similar to the conventional immersion method, in which ultrasonic waves are applied to the flaw detection surface of the object 4, and when the entire area is to be detected, the probe 5 is used.
In addition to scanning, it is also possible to scan by moving the base 9 on which the liquid tank A and the subject 4 are placed relative to the probe 5. Because of the configuration in which it is placed, flaw detection can be performed with ease similar to the direct contact method without being restricted by the type, shape, or dimensions of the object.

Furthermore, since the liquid tank can be made freely portable, flaw detection can be performed in real time.

[Effects of the Invention] As explained above, the liquid tank for ultrasonic inspection of the present invention has the following advantages:
The bottom surface of the liquid tank has a value that is the same as or approximates the acoustic impedance of the liquid in the liquid tank, and is made of a membrane that is fixed to the outer periphery of the liquid tank with a sag that can be deformed into any uneven surface shape. This makes it possible to perform flaw detection by touching the bottom of the liquid tank to the test surface of the test object installed outside the liquid tank.
To easily and precisely detect flaws in real time, without being affected by the type of specimen, shape, dimensions, surface roughness, etc., and without causing any adverse effects such as rust or contamination due to liquid intrusion into the specimen. It has excellent practical effects.

[Brief explanation of drawings]

The figure is a side sectional view showing one embodiment of the liquid tank for ultrasonic testing of the present invention. DESCRIPTION OF SYMBOLS 1... Peripheral wall, 2... Membrane, 3... Liquid, 4... Test object, 5... Probe, 6... Adjuster, 7... Stand, 8... Super Sound wave beam, 9...base, A...liquid tank.

Claims (1)

[Claims] 1. In a liquid tank for ultrasonic testing in which an immersion liquid is placed and a probe is immersed in the liquid, the bottom surface of the liquid tank is
It has a value that is the same as or approximates the acoustic impedance of the liquid in the liquid tank, and is formed of a membrane that is fixed to the outer periphery of the liquid tank in a sagging state so that it can be deformed into any uneven surface shape. Characteristic liquid tank for ultrasonic testing. 2. The liquid tank is configured such that the liquid tank can be vertically displaced from outside the tank while the bottom surface of the liquid tank is in contact with the flaw detection surface of the test object installed outside the tank. A liquid tank for ultrasonic testing according to claim 1.