JPS6042415B2 - Adapter for ultrasonic flaw detection of pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to an adapter used in a water immersion angle 2 transmission type ultrasonic flaw detection method developed by the present inventors for aging deterioration inspection of austenitic cast steel heating pipes, and particularly relates to a radial Fischer etc. Provides an adapter for axial defect detection.

Conventionally, it has been almost impossible to perform ultrasonic flaw detection on austenitic heat-resistant cast steel heating tubes such as steam catalytic reforming heating tubes, but the present inventor has developed a water immersion method that can effectively inspect such heating tubes. We have developed an ultrasonic flaw detection method using a two-angle transmission method.

The new ultrasonic flaw detection method is shown in Fig. 1 and briefly explained. A transmitting probe 3 and a receiving probe are placed at a predetermined angle and interval on the same circumference along the outer circumference of a pipe to be inspected 1 such as a heating pipe. The ultrasonic wave 5 is transmitted from the transmitting probe 3 through the wall thickness of the tube to be inspected in a straight line connecting two points A and B on the outer periphery of the tube to be inspected, and the receiving probe 4 collects transmitted echoes. By receiving this signal, it is possible to detect axial defects (radial fissure) within the wall thickness of the pipe to be inspected. In this case, the transmission and reception of the ultrasonic waves 5 between the tube 1 to be inspected and each of the contacts 3 and 4 is carried out by the water immersion method so as not to be affected by the surface properties of the tube 1 to be inspected. According to the method, the ultrasonic wave 5 is incident at an incident angle such that the ultrasonic wave 5 is transmitted in a straight line through the inner circumferential surface of the tube to be inspected and the thickness of the tube reflected from the bottom surface. Therefore, the ultrasonic wave 5 that is incident on the tube 1 to be inspected from the transmitting probe 3 at an angle of incidence i using the water immersion method is refracted at the refraction angle θ at the point of incidence A, and is refracted in the tangential direction within the wall thickness of the tube to be inspected. It passes through at a depth of d, and the incident point B
It is refracted at a refraction angle i with respect to the incident angle θ, and then received by the receiving probe 4. If there is an axial defect indicated by the symbol 6, an attenuated transmitted echo is transmitted to the receiving probe 4. Therefore, the existence of the defect 6 can be detected.
The outline of the equipment used in such water immersion angle 2 transmission type ultrasonic flaw detection method is shown and explained in Fig. 2. 1 is a pipe to be inspected, 2
is an adapter that houses a transmitting probe 3 and a receiving probe 4 and is disposed along the pipe 1 to be inspected.

In order to use the water immersion method, water is supplied from a water tank 7 via a pump 8 to a portion of the adapter 2 corresponding to the ultrasonic path between the probes 3 and 4 and the tube 1 to be inspected. As will be described later, water leaking through the pipe to be inspected 1 flows into the water receiver 9 disposed below the pipe to be inspected 1 and is discharged to the outside.
Even if the tube 1 to be inspected is installed in the heating furnace, there is no risk of water flowing into the heating furnace. The probes 3 and 4 for transmitting and receiving ultrasonic waves built into the adapter 2 are each mounted on a flaw detector 1.
0, and as shown in FIG. 11, the height of the transmitted echo is recorded. The present invention relates to an adapter for the above-mentioned device, and provides an adapter that has an excellent function particularly as an adapter for detecting defects in the axial direction. The adapter has a built-in probe and a receiving probe, and the transmitting probe and the receiving probe are attached along the outer circumferential surface of the tube to be inspected so that the angle is always fixed according to changes in the outer diameter of the tube to be inspected. It is located at a configured point that is attached so that it can be tracked.

The embodiment shown in FIGS. 3 to 5 will be described below.

The figure shows the adapter 2 attached to the pipe to be inspected 1. In the figure, the adapter 2 is pivotable via a pivot 15 such as a pin that intersects a pair of left and right angles 13 and 14 formed in an arc shape. The upper and lower pairs are flexible and angular. Reference numeral 16 denotes a pair of left and right probe built-in blocks into which the transmitting probe 3 or the receiving probe 4 is fitted and attached from the outside at a predetermined angle, and the above-mentioned flexible It is clamped and fixed between the angles 12.

The inner surface of the block 16 that comes into contact with the tube to be inspected 1 is formed into a concave surface with a desired curvature so that it can be easily fitted to the tube to be inspected 1 even if the outer diameter of the tube to be inspected 1 changes. In addition, a hollow part 18 is formed that opens from the surface of each of the built-in probes 3 and 4 facing the tube to be inspected to the inner surface of the block to perform the water immersion method, and a water supply port 19 that communicates with the hollow part 18. Water is injected as described above, and the inner surface of the block and the pipe to be inspected 1 are
Even if water leaks from the gap, the hollow portion 18 is constantly filled with water. Water leaking from inside the block 16 is discharged by the water receiver 9 as described above. Here, reference numeral 20 in the figure indicates a member for preventing the probes 3 and 4 from coming off.
In the adapter 2 with the above configuration, each probe 3 and 4 is connected to the block 1.
6, and by fitting the inner surface of the block to the tube 1 to be inspected and attaching the adapter 2 to the tube 1 to be inspected, each probe 3, 4 will always be connected to the tube 1 to be inspected, depending on the outer diameter of the tube 1 to be inspected. It has a fixed angle with respect to the test tube 1.

That is, as shown in FIG. 6, since the probe built-in block 16 is connected by the flexible angle 12, it can be swung around the pivot point C according to the outer diameter of the tube 1 to be inspected. Furthermore, if necessary, the inner surface of the block can be fitted to the tube 1 to be inspected by performing the same swinging operation centering on the block pivot 17, thereby attaching the probes 3 and 4 to the tube 1 to be inspected. It is possible to follow a fixed angle along the line. This is the 6th
In comparison with other adapters indicated by the reference numeral 2'' in the figure, in this case, the probe built-in block 16'' is fixed between a pair of upper and lower angles 12'' formed in a constant arc shape, so that the tube to be inspected and the tube to be inspected 1 do not fit together, and a large gap is created between the inner surface of the block and the tube to be inspected 1, resulting in a significant outflow of water, and the transmitting probe 3'' and receiving probe 4'' are covered. Since the angle relative to the test tube 1 varies and the distance between the probes 3'' and 4'' is constant, the receiving probe 4'' cannot receive the transmitted echo of the ultrasonic wave 5. On the other hand, in the above embodiment, if the angle of incidence of the ultrasonic wave 5 with respect to the tube 1 of each probe 3, 4 is selected in advance at a predetermined interval, the angle of incidence of the ultrasonic wave 5 can be set to 1. Regardless of the diameter, the incident angle 1 and the refraction angle 0 determined by this are kept constant, and as a result, even if the outer diameter of the tube 1 to be inspected changes, the ultrasonic wave 5 that passes through the wall thickness of the tube 1 to be inspected changes. The transmitted echo can be received by the receiving probe 4. However, if the outer diameter of the tube 1 to be inspected changes significantly, the inner surface of the block will no longer fit the tube 1 to be inspected, so the block must be replaced. As described above, the adapter of the present invention is used for detecting defects in the axial direction used in the water immersion angle two-angle transmission ultrasonic flaw detection method of pipes, and the transmitting probe and the receiving probe It is possible to follow the outer circumferential surface of the pipe to be inspected so that the angle is always fixed according to changes in the angle, so even if the outer diameter of the pipe to be inspected changes due to welds,
In addition, it is possible to perform ultrasonic flaw detection on pipes to be inspected with different outer diameters without changing blocks, and if the adapter of the present invention is used to perform ultrasonic flaw detection on pipes such as austenitic cast copper heating pipes, Pipes can be inspected more easily and quickly than conventional destructive inspections, and its industrial effects are significant.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the principle of the present invention, Figure 2 is a schematic diagram showing an example of a device used in the present invention, Figures 3 and 4 are front and plan views of the adapter according to the present invention, and Figure 5. is A in Figure 4.
-A sectional view and FIG. 6 are action explanatory diagrams of the adapter according to the present invention and the comparative adapter. 1...Tube to be inspected, 2...Adapter,
3... Sending probe, 4... Receiving probe.

Claims (1)

[Claims] 1. An adapter that incorporates a transmitting probe and a receiving probe on the same circumference along the pipe to be inspected, and the transmitting probe and the receiving probe are constantly adjusted according to changes in the outside diameter of the pipe to be inspected. An adapter for ultrasonic flaw detection of a tube, characterized in that it is configured to be attached so as to be able to follow the outer peripheral surface of the tube to be inspected so as to have a fixed angle.