JPH01142456A - Ultrasonic medium - Google Patents

Abstract

PURPOSE:To achieve an ultrasonic flaw detection at a weld part very efficiently, by coating the weld part with an ultrasonic medium having iron powder mixed with an adhesive or a rubber-like material to finish the surface thereof flat. CONSTITUTION:Iron powder is added and mixed at a rate of 80% per 20% of an epoxy resin to form an ultrasonic medium 3. The weld part 2 is coated with the medium 3 and the surface thereof is finished flat with a trowel. This enables the obtaining of a smooth surface in a relatively simple manner to make a uniform ultrasonic wave incident into the weld part from a vibrator 4 thereby achieving an ultrasonic flaw detection at the weld part 2 very efficiently.

Description

[Detailed Description of the Invention] [Prior Art] For example, as shown in Fig. 2, when the ends of a large diameter steel pipe 1 are butt welded at a construction site and the welded portion 2 is subjected to ultrasonic flaw detection. , the surface of the welding part 2 is not smooth, and the ultrasonic waves cannot be made uniformly incident on the welding part from the vibrator.

Therefore, conventionally, the outer circumferential surface of the welded portion 2 was smoothed using a hand grinder or the like before ultrasonic flaw detection was performed.

[Problem to be solved by the invention J However, grinding the entire circumference of a butt-welded joint of a large-diameter steel pipe requires a large number of man-hours and is an extremely inefficient operation. . For example, in the case of a butt welded part of a steel pipe with a diameter of 1 m, it took about 2 hours to finish it with a grinder.

The object of the present invention is to provide an ultrasonic medium that can solve the above-mentioned problems.

[Means for solving problems]

The ultrasonic medium of this invention has a surface that is not smooth.
It is used to coat iron powder to obtain a smooth surface, and is made by mixing iron powder with an adhesive or a rubber-like substance.

[Effect] Ultrasonic medium consisting of iron powder mixed with adhesive or rubber-like substance,
By coating the welding part and finishing the surface flat with a spatula, trowel, etc., it is possible to easily obtain a smooth surface for uniformly incident ultrasonic waves, and it also adheres closely to the uneven surface of the welding part. be able to. Since this ultrasonic medium contains iron powder, it has the same acoustic impedance to the ultrasonic waves as welded parts and steel pipes, so it is possible to perform flaw detection without reflection at the boundary surface. can.

[Embodiment 1] Hereinafter, a case will be described in which an embodiment of the present invention is applied to a butt welded portion of a large diameter steel pipe shown in FIG.

As the iron powder, we used iron powder for magnetic particle flaw detection as it has extremely fine particles that can be easily and uniformly mixed into adhesives and the like. Epoxy resin was used as the adhesive because it adheres closely to the welded parts and steel pipes and hardens in a short time. An ultrasonic medium was prepared by adding and mixing 80% iron powder to 20% of this resin.

This ultrasonic medium 3 is applied to the welded part 2 as shown in FIG. 1, and the surface is finished flat using a trowel. In this way, a smooth surface for making uniform ultrasonic waves incident on the welding part 2 from the vibrator 4 can be obtained relatively easily, and the medium 3
can be brought into close contact with the welded part 2. In this state, stable ultrasonic flaw detection could be performed.

For example, in the case of a butt weld of a steel pipe with a diameter of 1 TrL,
The working time to obtain a smooth surface was approximately 30 minutes, which was significantly shorter than the two hours required for conventional grinder finishing.

Note that the mixing ratio of iron powder to resin needs to be 60% or more with respect to 20% resin in order to perform stable flaw detection work.

The ultrasonic medium may also be made by mixing iron powder with a rubber-like substance. As the rubbery substance, for example, polyballon is used.

Although the above embodiment has been described with reference to the case where it is applied to a butt welded portion of steel pipes, it goes without saying that it can be widely applied to other welded portions and to corrosion, etc.

[Effects of the Invention] The ultrasonic medium of the present invention is as described above, and by using this ultrasonic medium, ultrasonic flaw detection of welded parts can be performed.
This can be done extremely efficiently compared to conventional methods.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of the usage state of the ultrasonic medium of the present invention, and FIG. 2 is an explanatory diagram of a butt welded portion of a steel pipe. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] This ultrasonic medium is made by mixing iron powder with adhesive or rubber-like material, and is used to coat the surface of a flaw detection area with an uneven surface to obtain a smooth surface.