JPS61159153A - Probe holder for ultrasonic flaw detection - Google Patents

Abstract

PURPOSE:To reduce the air bubble generation of a contact medium on a bottom surface facing the surface of the material to be detected and the surface of the material to be detected as much as possible and to improve the precision of flow detection by providing a supply path for the contact medium which spreads gradually toward the bottom surface. CONSTITUTION:A gap 24 is formed of a seal material 19 between the reverse surface 12a of a holder 10 and the peripheral surface of a pipe 12a. The supply path 13 spreads gradually from a mandrel 15 to the holder bottom surface 12a. When water as the contact medium is supplied from the mandrel 15 continuously, the water is pooled in the gap 24 at any time and overflows from its upper part. Then, an ultrasonic wave transmitted by an oblique probe 20 for transmission at a specific angle is propagated in the pipe 22 through the water in the gap 24, so that an oblique probe 21 for reception receives an echo attenuated by a defect when there is the defect in the middle or an unaffected echo through the water when not. When the water is supplied to the gap 24 through the supply path 13 in this state, the generation of air bubbles is reduced greatly and an excellent flow detection result is obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to ultrasonic flaw detection of a test material using a pair of transmitting angle probe and receiving probe. The present invention relates to a probe holder.

[Conventional technology]

In order to perform ultrasonic flaw detection on welded parts of centrifugally cast pipes, etc., a pair of transmitting and receiving angle probes held by a probe holder are moved along the longitudinal direction of the weld line or Conventionally, a flaw detection method has been practiced in which the holder is positioned so as to sandwich the weld line, and the holder is moved along the weld line in this state.

[Problem that the invention seeks to solve]

By the way, conventionally, a couplant supply pipe was opened in the space formed between the bottom surface of the probe holder and the surface of the test material, and the couplant was discharged into the space from the opening. A large number of bubbles are generated within the space, which causes a problem in that the ultrasonic waves are scattered by the bubbles.

[Means for solving problems]

In view of such conventional problems, the present invention has a shape that gradually spreads toward the surface of the material to be inspected (the opposing bottom surface [effect]). When the couplant is supplied to the space formed between the bottom surface and the test material, bubble generation in the medium is suppressed.

〔Example〕

1, 2, and 3 are a front view, a top view, and a bottom view showing one embodiment of the probe holder according to the present invention, respectively, and FIG. 4 is a point A in FIG. 1. FIG.

This probe holder 10 has a probe guide groove 1 into which a transmitting bevel probe and a receiving probe, which will be described later, are respectively fitted and inserted.
1, and its bottom 12 is formed in an arc shape so as to be along the surface of the material to be tested (centrifugally cast tube), which will be described later.

A couplant supply channel 13 is formed in this holder 10 and has a shape that gradually widens toward the bottom portion 12, as shown by the dotted line in FIG. As shown in FIG.
4, its upper portion communicates with the base 15 screwed onto the side wall 141c, and its lower portion opens to the lower surface 12a of the bottom portion 12, as shown in FIG.

The outer surface of the side wall 14 is marked with a scale 1 along the groove.
6 is attached, and a slit 17 is formed in the bottom portion 12 in such a manner as to divide the bottom portion into left and right halves. An arm portion 18 is protruded from the center of the upper part of the holder 10, and a fifth arm portion 18 is provided.
As shown in the figure, the bottom surface 12L excluding the lower part of the front side wall L4
A sealing material 19 made of nylon sponge or the like is adhered around the periphery.

Note that the holder 10 of this embodiment is made of the same material (for example, acrylic) as the material of the wedge of the probe, which will be described later.

As shown in FIG. υ, a transmitting bevel probe 21 and a receiving bevel probe 21 are respectively mounted in the groove Ll. Each of the probes 21 is slidable within the groove 11, and their position and spacing are known by the scale 16.

The holder 10 to which the probe 21 is attached is used for flaw detection of a specimen placed directly on the pin. That is, the sixth
As shown in the figure, the holder 10 is arranged in such a manner that the lower surface 12a is located on the welding line n of the circular-centered cast pipe B, which is the test material, and the holder 10 is placed along the welding line O, that is, in the local direction of the pipe n. is moved along. The holder 10 is supported and moved by a rotating jig (not shown), and the upper end of the arm 18 is pressed by a spring (not shown), so that its lower surface 12a is pressed against the circumferential surface of the tube. Forced to the side.

By the way, as shown in FIG. 6, the holder lower surface 12a and the pipe n
A gap μ is formed by the sealing material 19 between the circumferential surfaces, and a couplant such as water is pooled in this gap during flaw detection.

In the holder 10 of this embodiment, water as the couplant is supplied from the base 15, and the supplied water flows into the gap through the supply path 13. As described above, the supply path 13 has a shape that gradually widens from the base 15 toward the holder bottom surface 12a. According to experiments, when water is supplied into the void row through the supply channel 13 having such a shape, the generation of air bubbles is significantly greater than when water is directly supplied into the void row through a pipe. This made it possible to obtain extremely good flaw detection results.

Water is continuously supplied from the cap 15, so that water is always pooled within the row of voids, and water overflows from above the voids. As shown in FIG. 7, the ultrasonic wave (transverse wave) sent out at a predetermined angle from the transmitting angle probe propagates through the tube n through the water in the gap row, and its propagation path If there is a defect in the middle, echoes are attenuated by the defect, and if there are no defects, echoes that are unaffected by the defect are received by the receiving angle probe ZHC through water. be done.

In addition, the slit 17 formed in the bottom part of the holder is
This serves to prevent the ultrasonic waves sent out from the probe from directly going around to the probe 21 side.

The flaw detection using the probes 20 and 21 is first performed in such a manner that their centers are located on one of the 7-age line 23a of the weld line A, as shown in FIG. 8, and then as shown in FIG. This is done in such a manner that their centers are located on the other 7-generation line 23b as shown in FIG.

By the way, there are two types of defects such as creep cracks: those along the axial direction of the test material 22 and those along the circumferential direction.

The holder 10 of the above embodiment is applied to detect the former defect, and the holder I as shown in FIGS. 10 to 13 is applied to the latter defect detection.

This holder I, like the holder 10, has a groove 31 into which a probe is fitted, and has a scale engraved on the surface of the front side wall 32F. Then, on the right side wall thereof, there is a bent couplant supply path I having one end opening to the right side of the side wall and the other end opening to that one end side of the bottom surface of the holder.
is formed, and a cap 37 is attached to one end of the supply path I.

In the groove 31 of this holder 10, as shown in FIG. 13, a transmitting bevel probe and a receiving bevel probe 39 are arranged. This holder 10 is rotated by a rotating jig (not shown) along the longitudinal direction of the circular-centered cast tube, which is the test material, and between the front side wall 32F and the rear side wall 32F, as shown in the figure.
The convex strip of welding line n is positioned in such a manner that it fits into the arcuate recess 40 formed at the center of the lower end of R, and is moved along the welding wire device. .

Of course, during flaw detection, couplant filter water is supplied from the mouthpiece 37, and this water passes between the supply channels to the lower ends of the front and rear side walls 32F and 32R, the bottom surface of the holder, and the pipe n.
It is pooled in a space 41 formed by the circumferential surface of.

The holder I is also made of the same material (for example, acrylic) as the wedge 39 between the probes.

〔Effect of the invention〕

Since the holder according to the present invention is equipped with a couplant supply path having a shape that gradually widens toward the bottom surface facing the surface of the specimen, it is possible to generate bubbles of the couplant on the bottom surface and the surface of the specimen. It is possible to improve the accuracy of flaw detection by reducing the number of defects.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are a front view, a top view, and a bottom view showing one embodiment of the probe holder according to the present invention, respectively, and Figure 4 is taken along line A-A in Figure 1. 5 is a cross-sectional view, FIG. 5 is a diagram showing how the sealing material is arranged, FIG. 6 is a perspective view showing how the holder shown in FIG. 1 is arranged with respect to the specimen, and FIG.
The figure is a cross-sectional view showing the arrangement of the probe, Figures 8 and 9 are conceptual diagrams showing the manner of flaw detection, and Figures 10 and 11 show defects along the circumferential direction of the test material. A front view and a plan view showing an example of a holder applied in the case of detection,
FIG. 12 is a sectional view taken along line BB in FIG. 10, and FIG. 13 is a diagram showing how the holder shown in FIG. 10 is arranged with respect to the specimen. 10, 30... probe holder, 11, 31...
Groove, 12...bottom, 12a...bottom, 13, 36
... Supply path, 14.32F... Front side wall, 15,
37...cap, 16, 33...scale, 17-...
Slit, 18...Arm, 19...Seal material, beauty, 3
8...Bevel probe for transmission, 21, 39...Bevel probe for reception, n...Central cast tube, n...Welding line, U
...Void. Figure 1 Figure 2 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12

Claims (1)

[Claims] A probe holder that holds a transmitting angle probe and a receiving angle probe at a predetermined interval has a shape that gradually widens toward the bottom surface facing the surface of the material to be tested, and 1. A probe holder for ultrasonic flaw detection, comprising a couplant supply channel that opens at the bottom.