JPH04122854A - Divided type ultrasonic probe - Google Patents

Abstract

PURPOSE:To enhance the detection accuracy of the internal flaw of an object to be inspected by a method wherein respective metal plates are arranged on the sides of both delay blocks as shield plates and a soft non-metal plate is arranged between both metal plates to be bonded to said plates and an uneven surface for irregular reflection is formed to the arbitrary bonding surfaces of the plates. CONSTITUTION:A sandwich structure part is interposed between delay blocks 2, 5 and the sonic wave from the delay block 2 on the side of a detection element 1 is attenuated by a metal plate 7A and, next, the residual sonic wave is shielded and sharply attenuated by a soft non-metal plate 7C excellent in softness and, subsequently, a minute amount of the residual sonic wave is attenuated and erased by the metal plate 7B present on the side of the delay block 5 of the detection element. In order to further enhance this effect, unevenness is provided to the bonding surfaces of the metal plates 7A, 7B and the soft non-metal plate 7C to accelerate the irregular reflection of a sonic wave and the passing quantity due to secular deterioration is more reduced. Since the soft non-metal plate 7C is held between the metal plates 7A, 7B, the degree of the damage due to the uneven surface of an object 8 to be inspected becomes slight at the time of flaw detection in such a state that a probe is set to the surface of the object 8 to be inspected and the flaw in the object 8 to be inspected can be stably and accurately detected over a long period of time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an improvement in a shielding plate that prevents direct propagation of sound waves from the transmitting side to the receiving side between the delay blocks of a split-type ultrasonic probe. be.

[Prior art] Conventional split-type ultrasonic probes are widely introduced in Figure 3.13, page 61 of "Ultrasonic Flaw Detection Test A," published by the Japan Nondestructive Inspection Association, 557.10.25. It has been adopted. As shown in FIG. 2, this consists of a transmitting element 3 consisting of a transmitting transducer 1 and a delay block 2, a receiving element 6 consisting of a receiving transducer 4 and a delay block 5, and a delay block 2 of each of these elements 3.6. The shielding plate 7 is made of cork (0.8 m) that does not transmit sound waves from the transmitting element 3 side.
A soft non-metallic plate such as +o thick) is used.

To set this split-type ultrasonic probe on a subject, the lower end face of the delay block 2.5 is set close to the surface of the subject 8 via the liquid film 9, and the lower end face of the shielding plate 7 is placed close to the surface of the subject 8. 8 to prevent surface waves reflected from the surface of the transmitting element 3 side of the object 8 from entering the receiving transducer 4 side, and while maintaining this state, shift the entire element parallel to the object 8. This is to detect defects within 8.

[Problems to be Solved by the Invention] Since the lower end surface of the shielding plate 7 is in contact with the surface of the subject 8 as described above, it is not directly affected by the unevenness of the surface properties of the subject, such as waves and surface scratches. is damaged.

If the shielding plate 7 is damaged, not only will the surface waves directly pass through the damaged part, but the cork will deteriorate and absorb liquid, causing the sound waves from the delay block 2 on the transmitting element 3 side to be transmitted to the delay block 5 side on the receiving element 6 side. This results in a direct propagation of the defects, resulting in a significant impediment to the accuracy of detecting internal defects in the test object.

The present invention has been made to solve this problem.

[Means for Solving the Problems] The features of the present invention for solving the above problems are as shown in one embodiment shown in FIGS. 3, a receiving element 6 consisting of a receiving transducer 4 and a delay block 5, and each of these elements 3.6
In a split-type ultrasonic probe consisting of a shielding plate 7 interposed between delay blocks 2.5, metal plates 7A and 7B are provided on both delay blocks 2.5 sides as the shielding plate 7, and each metal plate is The split-type ultrasonic probe is characterized in that a soft non-metallic plate 7C is bonded between 7A and 7B, and an uneven reflection surface 7D is formed on any arbitrary surface of these bonded surfaces.

[Function] [Example] That is, conventional shielding plates have simply adopted soft non-metallic plates such as cork that are difficult to transmit sound waves, such as sound absorbing materials, but the present invention uses metal plates 7A that transmit sound waves, Soft non-metallic plate 7 between 7B
It has a sandwich structure in which C is joined.

Normally, a portion of ultrasound is reflected at an interface between an object through which the ultrasound is traveling and another object, and the rest passes through. Also, the ratio is determined by the sound speed and density of the two objects touching at the interface.

The present invention makes use of this principle and uses the delay block 2 as described above.
．． The sandwich structure is interposed between the transmitting element 1 and the transmitting element 1.
The sound waves from the delay block 2 on the side are attenuated by the metal plate 7A,
Next, the remaining sound waves are attenuated by a shielding part 7C made of a soft non-metallic plate made of rubber, vinyl, etc. with excellent flexibility, and then a minute amount of residual sound waves is attenuated and eliminated by a metal plate 7B on the delay block 5 side of the receiving element 6. That's what I do.

Furthermore, in order to enhance this effect, unevenness is provided on the joining surfaces of the metal plates 7A, 7B, the soft non-metallic plate 70, etc., thereby promoting scattering and reflection of sound waves and further reducing the amount of sound waves passing through due to aging.

Furthermore, in the present invention, since the soft non-metallic plate 7C is sandwiched between the strong metal plates 7A and 7B, when the soft non-metallic plate 7C is placed on the surface of the specimen 8 for flaw detection, the degree of damage due to surface irregularities of the specimen 8 can be reduced. This makes it possible to detect defects inside the object 8 stably and accurately over a long period of time.

In FIG. 1, 8 indicates a water film, and 9 indicates a steel plate, which is the material to be tested.

The metal plates 7A and 7B are made of copper, stainless steel, or the like, and have a thickness of 0.1 to 13 mm.

As the soft non-metallic plate 7C, rubber, cork, vinyl,
Teflon or the like is used to make the thickness 01 to 0.2+w■.

The irregular reflection surface 7D may have a Δ shape, a double wave shape, or the like.

The delay blocks 2 and 5, the metal plates 7A and 7B, and the soft non-metal plate 7C may be bonded using an appropriate adhesive.

[Effect of the invention] The propagation of sound waves between the delay blocks and the sound wave short circuit between the delay block, the surface of the test material and the delay block are almost completely blocked by the metal plate and the soft non-metallic plate, thereby eliminating internal defects in the test object. This greatly improves detection accuracy.

In addition, a soft non-metallic plate with excellent sound wave shielding function, especially the lower end that comes into contact with the surface of the test material, is held between the metal plate to prevent damage caused by contact with the surface of the test material, which is advantageous in extending its life. It was shown that it is possible.

Since the joint surface between the lower end of the soft non-metallic plate and the metal plate is not stripped and damaged due to stiffness, it is possible to reliably prevent the deterioration of the sound wave shielding function of the soft non-metallic material due to water seepage from the joint surface.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing an embodiment of the present invention, FIG. 2 is an enlarged view of the main part within circle S in FIG. 1, and FIG. 3 is an explanatory cross-sectional view showing a conventional example. 1...Oscillation resonator, 2.5-Delay block, 3-Oscillation element, 4-Reception resonator, 6-Reception element, 7-Shielding plate, 7A, 7B-Metal plate, 7C-Nonmetal Plate, 7p-uneven surface, 8-・Subject

Claims (1)

[Claims] 1. A transmitting element (3) consisting of a transmitting transducer (1) and a delay block (2), a receiving transducer (4) and a delay block (5);
), and each of these elements (3), (
In the split-type ultrasonic probe consisting of a shielding plate (7) interposed between the delay blocks (2) and (5), both delay blocks (2) and (5) are used as the shielding plate (7). )
metal plates (7A) and (7B) on each side;
) and (7B), a soft non-metallic plate (7C) is bonded and arranged, and an uneven reflection surface (7D) is formed on any surface of these bonded surfaces. Child.