JPH0142035Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention reduces the amount of weld build-up for ultrasonic waves when detecting flaws in weld build-up parts of pressure vessels etc. using ultrasonic waves. The present invention relates to an ultrasonic probe for weld build-up parts that is suitable for performing ultrasonic flaw detection with high precision even on parts such as weld build-up parts that have curvature.

[Conventional technology]

Figures 1 and 2 show the structure of a weld overlay for conventional ultrasonic flaw detection. Such a shape of the weld overlay is used when a small-diameter cylindrical object is attached to a thick-walled pressure vessel or for an irregularly shaped joint. Such weld overlays are often inspected and repaired after joining cylindrical objects and the like.

In both FIGS. 1 and 2, the overlay thickness is relatively thin, so a separate type probe with a short focal length in the steel is used for flaw detection.

[The problem that the idea aims to solve]

However, in this case, the focal length is short.
4.5 to 6 mm, and at close distances of 2 mm or less, there is a third
As shown by line A in the figure, the echo height was extremely reduced, defects were not detected sufficiently, and the size of the defects could not be evaluated, so the reliability was considered to be low.

Furthermore, since the curvature of such a built-up portion has a small diameter, the distance between the split type probe and the surface to be inspected becomes large, making it easy for the couplant to flow and making it difficult for ultrasonic waves to enter the probe.

In any case, in order to perform ultrasonic flaw detection after overlaying, it is necessary to have a thickness that does not cause any problem even if the sound waves are attenuated, or a thickness that is necessary for sound wave incidence (extra thickness part 1), as shown in Figures 1 and 2. The method used was to remove the excess thickness 1 after providing a flaw and detecting the flaw, which was extremely uneconomical.

The purpose of the present invention is to solve the above-mentioned problems of the conventional technology and to accurately detect flaws even when the defect depth is shallow while reducing weld build-up areas on small-diameter cylindrical objects and irregularly shaped joints. An object of the present invention is to provide an ultrasonic probe for weld build-up parts that can perform

[Means to solve the problem]

The above-mentioned purpose is to form a cone in which the cross-sectional area of the part that contacts the overlay welding material is smaller than the cross-sectional area of the cylindrical part that accommodates the split-type probe and the part that contacts the split-type probe. This is achieved by providing a wedge which is trapezoidal and consists of a truncated cone section with an acoustic dividing wall in the center.

[Effect]

By using a wedge with a truncated conical part where the cross-sectional area of the part that contacts the overlay welding material is smaller than the cross-sectional area of the part that contacts the split type probe, it can be used for overlay parts with curvature. In order to ensure sound wave propagation and stable flaw detection, the cross-sectional area of the part that contacts the overlay welding material is made small to prevent the formation of gaps, and even when the defect depth is shallow, the propagation path within the wedge is minimized. is long,
This prevents the accuracy of flaw detection from decreasing.

In addition, by providing an acoustic dividing wall, interference between emitted and received waves is prevented, and the diameter of the split type probe and wedge can be reduced, making it easier to handle overlay welded materials with small curvature. Become.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 4 is a longitudinal sectional view showing one embodiment of the ultrasonic probe for the weld build-up portion of the present invention.

In FIG. 4, a wedge 3 is detachably attached to a cylindrical split probe 2. The wedge 3 consists of a cylindrical portion that accommodates the split type probe 2 and a truncated cone portion. As shown in the figure, the truncated cone portion is formed into a truncated cone shape in which the cross-sectional area of the portion that contacts the overlay welding test material 7 is smaller than that of the portion that contacts the split type probe 2 .

Further, an acoustic dividing wall 5 is provided in a diametrical direction passing through the center of each of the cylindrical portion and the truncated conical portion of the wedge 3. A transmitting transducer 6 and a receiving transducer 9 are installed in the split type probe 2 with an acoustic dividing wall 5 in between. Cables 10 are connected to the transmitting vibrator 6 and the receiving vibrator 9, respectively.

Next, the operation of the ultrasonic probe for the weld overlay constructed as described above will be explained.

The ultrasonic beam 4 emitted from the transmitting transducer 6 in the split type probe 2 passes through the truncated cone of the wedge 3,
The ultrasonic beam 4 is focused on the surface layer of the overlay welding test material 7, is reflected by a defect 8 in the overlay welding test material 7, passes through the truncated cone of the wedge 3 again, and reaches the receiving transducer 9. will be received.

Figure 6 is a comparison of the focal length l of the split type probe 2 that does not use the wedge 3 of the present invention and the focal length l' of the ultrasonic probe that uses the wedge 3 of the present invention. .

In FIG. 6, in the case of the split type probe 2 that does not use the wedge 3, it has a structure in which the focal length is connected to a depth of 4.5 to 6 mm, but by attaching the wedge 3 as in the present invention, The focal length l' of the split type probe 2 moves toward the surface layer of the material 7 to be overlay welded by an amount corresponding to the height h of the wedge 3 converted to the intermediate distance of the steel.

Therefore, it is effective in detecting the defect 8 existing in the surface layer, but even in the deep part, there is almost no attenuation of the sound wave as shown by curve B in FIG. 3, making it easy to detect defects in the deep part. In addition, since it has an acoustic dividing wall 5, interference between transmitted waves and received waves is prevented, and the diameters of the divided type probe 2 and wedge 3 are made small, making it compatible with overlay welding specimens 7 with small curvature. be able to.

Furthermore, since the wedge 3 is detachable, even if the wedge 3 wears out, it can be easily replaced.

FIG. 7 is a sectional view showing another embodiment of the present invention;
FIG. 8 shows a side view of FIG. 7, and the same parts as in FIG. 4 are designated by the same reference numerals. 7 and 8, the difference from the one shown in FIG.
1 was established. As a result, the acoustic partition walls 5 of the split type probe 2 and the wedge 3 are always aligned, the rotation of the split type probe 2 and the wedge 3 is prevented, and stable flaw detection is always possible.

[Effect of idea]

As described above, according to the present invention, ultrasonic flaw detection can be performed from the surface layer to the deep part of the test material, and test materials with small curvature can be detected in their finished shape.
There is no need for extra overlay of the material to be tested, which is very effective.

[Brief explanation of the drawing]

Figures 1 and 2 are longitudinal cross-sectional views showing conventional overlay structures for ultrasonic flaw detection, Figure 3 is a diagram showing attenuation of defect echoes with respect to defect depth, and Figure 4 is a weld overlay of the present invention. 5 is a plan view of FIG. 4, and FIG. 6 is a split-type probe that does not use a wedge in the present invention and a wedge-based probe in the present invention. FIG. 7 is a diagram comparing the focal lengths of the split type probes, and FIG.
FIG. 1... Excess flesh part, 2... Split type probe, 3...
Wedge, 4... Ultrasonic beam, 5... Acoustic dividing wall, 6
...Transmission transducer, 7... Material to be overlay welded, 8...
...defect, 9...receiving transducer, 10...cable, 11...groove, A...wedgeless attenuation curve, B...
Wedge attenuation curve, l, l'... focal length, h... wedge height.

Claims (1)

[Scope of utility model registration request] In an ultrasonic probe for a weld build-up part having a split type probe for ultrasonic flaw detection of a material to be overlay welded, the split type probe includes a cylindrical part for housing the split type probe; a truncated conical part in which the cross-sectional area of the part that contacts the overlay welding material is smaller than the cross-sectional area of the part that contacts the split type probe, and has an acoustic dividing wall in the center; An ultrasonic probe for a weld build-up part, which is characterized by having a wedge.