JPS5857708B2 - Hot ultrasonic probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a probe used for ultrasonic flaw detection of high temperature conductive materials.

Ultrasonic flaw detection is very useful as a technique for detecting internal defects in materials, but commonly used ultrasonic probes using piezoelectric elements are difficult to apply to high-temperature materials.

Therefore, the present inventors invented an electromagnetic ultrasonic probe suitable for flaw detection of high-temperature materials and filed an application for the same.

(Japanese Patent Application No. 1983-101836, Patent Application No. 51-6755
issue).

Electromagnetic ultrasonic probes are in principle resistant to heat and are suitable for flaw detection in high-temperature materials, but the above-mentioned prior invention uses heat-resistant nonmetallic materials or nonmagnetic metal materials to further improve heat resistance. It has a configuration in which part or all of the electromagnet and coil are built into the cooling case.

Although the ultrasonic probe of this prior invention is excellent in terms of heat resistance, it has the following drawbacks.

When a heat-resistant non-metallic material is used for the cooling case, there are problems with the workability and strength of the case, and when a non-magnetic metal material is used, it is difficult to apply high-frequency pulsed current to the flat transmitting/receiving coil. The changing magnetic field generated during this process induces an induced current on the surface of the cooling case, which significantly reduces the efficiency of transmitting and receiving ultrasonic waves to the specimen, resulting in a decrease in flaw detection sensitivity. When a pulsed current is used as the magnetizing current of the electromagnet, there are problems such as being susceptible to the influence of a reverse magnetic field due to an induced current induced on the side surface of the case.

The present invention aims to compensate for the above-mentioned drawbacks and to provide an ultrasonic probe for high temperatures that is excellent in terms of durability and sensitivity. In the tentacle, a protective plate-like body formed by folding a non-magnetic metal tube through which a cooling medium can flow in a plane to form a single spiral, a double spiral, or a folded double spiral is attached to the test object of the flat transmitting/receiving coil. In addition, the above-mentioned protective plate-like body and a protective cylindrical body formed by winding a non-magnetic metal tube through which a cooling medium can flow in a single spiral, double spiral, or folded spiral shape are provided on opposing surfaces. The electromagnet and the flat transmitting/receiving coil are built into the constructed protective box.

The present invention will be described in detail below based on the illustrated embodiments.

FIGS. 1 to 4 are plan views showing examples of the shapes of the protective plate bodies made of non-magnetic metal tubes according to the present invention, in which FIG. 1 shows a folded shape, FIG. 2 shows a single spiral shape, and FIG. Figure 3 shows a double spiral shape.
FIG. 4 shows a non-magnetic metal tube formed in a folded double spiral shape.

By adopting such a shape, the protective plate 1 becomes non-inductive to changes in magnetic flux in the direction perpendicular to the plane of the paper, suppressing the generation of eddy currents, and the presence of the protective plate 1 prevents electromagnetic waves. It will no longer be an obstacle to passage.

Furthermore, by flowing a cooling medium such as water, oil, or air from the injection hole 11 toward the outlet hole 12, high cooling performance and heat resistance are achieved.

FIG. 5, FIG. 6, and FIG. 7 are perspective views showing examples of the shape of a protective box made of a non-magnetic metal tube according to the present invention.

The protective cylindrical body of the protective box 1' is made of a non-magnetic metal tube wound in a folded spiral shape as shown in FIG. 5, or in a single spiral shape as shown in FIG. Form.

Although the bottom of the protective box 1' is not shown, it can be seen in the above-mentioned figures 1~
One of the protective plates shown in FIG. 4 is used.

By forming the protective box 1' in this manner, no induced current is generated even when the magnetic flux passing through the protective box 1' changes.

Injection hole 11. The fact that the cooling medium can flow through the outflow holes 12 is the same as in the case of the protective plate shown in FIGS. 1 to 4.

FIG. 8 is a sectional view showing an example of the configuration of an ultrasonic probe according to the present invention, in which an ultrasonic probe in which an electromagnet 2 and a flat transmitting/receiving coil 3 are built into a protective box 1' is brought close to a subject 4. This figure shows the state in which they are arranged.

The electromagnet 2 is energized to generate magnetic flux on the surface layer of the subject 4,
When a high-frequency pulse current is applied to the transmitting/receiving coil 3, electromagnetic waves are transmitted and propagated through the bottom surface of the protective box 1', and an induced current flows on the surface of the subject 4.

Ultrasonic waves are generated within the object 4 due to the interaction between the magnetic flux and the induced current, and ultrasonic flaw detection is performed.

In addition to the cooling effect, the cylindrical body of the protective box 1' in the present invention plays an important role depending on the excitation method of the electromagnet.

In other words, when magnetizing the electromagnet 2 with a current that changes over time, such as alternating current, pulsating current, or pulse current, the electromagnet 2
The magnetic field generated by this changes, causing the protective cylinder of the protective box to
If a metal body is wound into a cylindrical shape as shown in 5 in the figure, there is a drawback that eddy currents are generated and the magnetic field is weakened. A strong magnetic field is obtained without generating any current.

However, when the electromagnet 2 is magnetized by direct current, even the structure of the protective cylinder as shown in FIG. 9 can be sufficiently used because the magnetic field does not weaken.

Fig. 10 shows another embodiment of the present invention, which is an ultrasonic probe that transmits and receives ultrasonic waves of different modes by changing the arrangement of the electromagnet 2 from Figs. 8 and 9, and magnetization by pulsed current, alternating current, etc. The configuration is such that it is also possible.

Finally, the protective plate-like bodies in the folded, double spiral, and folded double spiral shapes described in the embodiments, the double spiral, and folded spiral protective box-tubes, and the single spiral shape shown in FIG. The differences between this protective plate-like body and the single-spiral protective box-tube body shown in Fig. 6 will be described below.

In a single-spiral protective plate or single-spiral protective tube, electric and magnetic induction occurs due to changes in magnetic flux in the direction perpendicular to the surface of the protective plate or protective tube. Since it is not completed, no current will flow.

However, since there is an electromotive force, there will be a large potential difference between adjacent tubes, and care must be taken to ensure that the insulation between the tubes has a fairly high insulation voltage.
Care must be taken to ensure that 2 does not short-circuit in, for example, a once-through pump.

On the other hand, when non-magnetic metal tubes are wound in a folded, double spiral, folded double spiral, double spiral, or folded spiral shape, the directions of adjacent tubes are different, so electromagnetic waves are generated due to changes in magnetic flux. Since no induction occurs and almost no potential difference occurs between the tubes, the insulation can be of a relatively low grade, and the injection hole 11
, it has the advantage that there is no problem even if there is a short circuit at the outflow hole 12.

Therefore, in the present invention, the winding shape of the non-magnetic metal tube of the protective plate-like body or the protective box-tube body is as shown in FIGS. 3 and 7.
It is preferable to have a double spiral shape, a double spiral shape, a folded spiral shape as shown in FIGS. 1 and 5, a folded spiral shape, or a folded double spiral shape as shown in FIG. 4.

However, single spiral or single spiral protective plates and protective box cylinders as shown in Figures 2 and 6 also have the advantage of being easy to process, and can be applied if sufficient insulation is provided. It is possible.

The outer diameter of the non-magnetic metal tube used in the various embodiments described above is
In order to prevent the occurrence of eddy currents, it is desirable to limit the time to about 4 hours or less.

As described above, the present invention provides a highly sensitive and durable electromagnetic ultrasonic probe for ultrasonic flaw detection of high-temperature materials, and has high industrial value.

[Brief explanation of drawings]

FIGS. 1, 2, 3, and 4 are plan views showing examples of the shape of the protective plate in the embodiment of the present invention, and FIGS. 5 and 6 are
7 are perspective views showing examples of the shape of the protective box-tube body in the embodiment of the present invention, and FIGS. 8, 9, and 10 are device configurations of the ultrasonic probe in the embodiment of the present invention. It is a sectional view showing an example. 1: Protective plate, 1': Protective box, 11: Cooling medium injection hole, 12: Cooling medium outflow hole, 2: Electromagnet, 3: Transmitting/receiving coil, 4: Test object, 5: Metal plate protective cylinder .

Claims (1)

[Scope of Claims] 1. In an electromagnetic ultrasonic probe having an electromagnet and a plate-shaped transmitting/receiving coil, a cooling medium can flow freely, which is formed into a plane folded shape, a single spiral shape, a folded double spiral shape, etc. 1. A hot ultrasonic probe, characterized in that a protective plate-like magnetic metal tube is disposed between the coil and the subject. 2. For the protection of non-magnetic metal tubes that are folded flat, formed in a single spiral, folded double spiral, etc. in an electromagnetic ultrasonic probe that has an electromagnet and a flat transmitting/receiving coil, and are capable of free flow of cooling medium. A protective cylindrical body composed of a plate-like body and a protective cylindrical body made of a non-magnetic metal tube formed in a single spiral, double spiral, double spiral, folded spiral shape, etc. through which a cooling medium can flow is connected to the electromagnet and A hot ultrasonic probe characterized by a built-in coil.