JPS58166257A - Flaw detecting method internally ribbed pipe - Google Patents

Abstract

PURPOSE:To enable the detection of a defect such as seizure falw along spiral groove, by moving a means which is inserted loosely into an internally ribbed pipe and holds a suitable number of probe for flaw detection in the longitudinal direction of said pipe while rotating the same with respect to the pipe. CONSTITUTION:A holder 4 is inserted loosely into an internally ribbed pipe 1, and for example, eight pieces of probe 5 for eddy current flaw detection are held to said holder. Said holder 4 is moved in either forward or backward direction by the distance corresponding to the overall length of the pipe 1, by which the respective corners of forward and backward spiral groove 1b can be defected of flaw over the entire length by one time of scanning. Since the probe for flaw detection are scanned along the spiral groove in the above-mentioned way, the defect such as seizure flaw along the spiral groove formed on the inside surface of the internally ribbed pipe is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for exploring the interior of a tube with an inner ribbed surface having one or more spiral ribs on the inner surface of the tube.

In the case of evaporation/a used in the heat exchanger of Boi 2, the pipe has one or more spiral-shaped brim formed on the inner surface of the pipe.
In this case, a so-called 15R internal lipped tube is used, which is formed with a single thread or a spiral rib. As shown in the perspective view in Fig. 1 and the vertical-section view in Fig. 2, there is a
Monument 1b with a row or multiple rows (the one shown is to the fourth power), I say n
An inward lipped tube 1 is used which is formed with a lip (a protrusion formed between matching eyelid grooves) la. In addition, in order to facilitate the connection by welding of the inner ribbed pipe 1 l/j shown in the figure, grooves of appropriate width and thickness extending in the longitudinal direction of the pipe are formed at opposite positions in the outward direction of the pipe. I'm here.

The reason for using such a tube 1 with internal ribs is that the design requirements for boilers tend to become more and more severe in order to improve thermal efficiency and downsize. This is to prevent the film boiling phenomenon in the steam pipe that causes burnout.

The above-mentioned line defects on the outer surface of a tube with internal ribs and defects parallel to the longitudinal direction of the tube on the inner surface can be detected by performing ultrasonic flaw detection or current flaw detection from the outer surface of the tube. Although it is possible, there is no proper flaw detection method for defects such as seizure flaws caused by the die during the formation of the spiral grooves along the NFC spiral grooves formed on the inner surface of the tube, and only visual inspection is performed. I'm doing f.

The present invention was created in consideration of the above circumstances, and is a particularly useful method for removing defects such as seizure defects along the inner surface of the inner ribbed tube. The purpose is to provide

Exploration of inward ribbed tube according to the present invention 114') j ih i
l. In a method for inspecting the inside of a pipe with an internal lip formed by one or more spiral #4# southward inward,
By rotating the means for holding the rope hold IA in the longitudinal direction of the pipe with inward ribs while rotating it, It is characterized by scanning the probe along a spiral screen.

The present Ql will be specifically explained below with reference to drawings showing embodiments thereof. FIG. 3 is a schematic vertical cross-sectional view showing the real axis state of the method of the present invention, and FIG. 4 is a schematic cross-sectional view along the IV-rating line of the third factor. Reference numeral 1 is a tube with internal ribs as described above, and the inward VC of the tube is a four-striped piece spiral-shaped 1t), in other words, the rib 1a is formed on the outside of the tube rII11. There are n. The inside lip 4-r is stretched freely inside the body 1.
A mandrel 2 that supports a glove 5 for shallow water exploration, which will be described later.
is rotatably supported by a holder number at its rear end fi2a. On the other hand, the tip part 2bIICr of the mandrel 2
L, eight flow flaw detection probes 5 are mounted radially so that their tips are pressed substantially perpendicularly to each corner of the spiral 141b. By moving the mandrel 2 in the longitudinal direction of the tube 1 with an inward lip, a mandrel for guiding the eddy current flaw detection probe 5 along the spiral core 1b can be created.

FIG. 5 shows a partially enlarged schematic cross-sectional view (cross-sectional view taken along the marma line in FIG. 3) of the part to which the eddy current flaw detection probe 5 is attached, and as shown in the figure, The eddy current flaw detection glove 5 has a structure in which a detection coil 6a is embedded in the tip inside thereof, and a coil 5b is embedded in a position separated by an appropriate distance from the detection coil 5a. is connected to the bridge circuit, and eddy current flaw detection is performed using the self-comparison method.In addition, the five eddy current flaw detection probes shown in the figure are connected to the bridge circuit, and the positive phase spring 6 is connected to the tip 2b of the mandrel 2. The tip of the jib is pressed against the corner of the spiral jib.
As a result, the *: end of the eddy current flaw detection glove 5 and the corner of the spiral groove 1b are not separated from each other, and the tip of the eddy current flaw detection probe 5 is This makes it possible to significantly reduce wear and tear.

When arranging the eddy current flaw detection probe 5 as described above to detect the surface and inside of the spiral groove of the inner ribbed tube 1, the holder 4 is moved in a direction parallel to the bone length direction of the inner ribbed Irt1. Third
By moving the chair in the direction of the arrow (in the direction of the arrow shown in the figure), turn the tube in the mandrel 2r in the forward and reverse directions, and attach it to the tip 2b. The helical shape F' of the inner ribbed tube 1 is
scan along the corner of l b. Therefore, the eddy current flaw detection on the surface and inside (in the vicinity of the corners) of the spiral groove of the inner ribbed part 1 is performed over its entire length =rne. In addition, the eddy current flaw detection probe 5 has a spiral groove 1b of 4-sakae.
Since eight pieces are arranged to scan the corners, by moving the holder 4 in either direction V (backward or forwardward) by a distance corresponding to the entire length of the circular lipped tube 1, the spiral shape N1b can be moved. It is possible to detect flaws over the entire length of each corner in one scan.
It goes without saying that four eddy current flaw detection probes 5 may be arranged to scan one corner of the holder 4t, and the entire length of each corner may be scanned by reciprocating the holder 4t. It is also possible to improve accuracy by comparing two suitable probes 5 at a time and differentially amplifying the signals emitted by them.

In this embodiment, the spiral #11 of the inner ribbed tube 1 is
Considering that defects such as seizure flaws are likely to occur at each corner of b, a hook current flaw detection probe 5 is placed at each corner, and the spiral groove lb is used to detect flaws in parts other than the corners. If necessary, a guide member 51 is arranged at each corner as shown in FIG. 6, and the probe 52 is moved from the inside of the strip fhvr 51 to the inner surface in order to position the tip of the eddy current flaw detection probe 52 at the part to be detected. The ribbed tubes 1 may be disposed at intervals along their length in the circumferential direction. In addition, unless the probe feeling is a problem, the rope b or 5 for the hook flow probe uIk is used.
The tip of the tip of 2 may have an appropriate width.In addition, an inner lip may be provided at the corner (if the lip 1a of 1 is replaced with a spiral groove lb as shown in Figure 7). A guide member 51 is disposed, and the probe 53 is separated from the guide member 51 by an appropriate distance in the circumferential direction of the circumferential lip seal tube 1 in order to position the tip of the glove 53 for detecting the III-minute VC damage current to be detected. It is also possible to perform a whirlpool stock exchange by placing the

In this example, there are four spiral #llll on the inner surface of the tube.
1b, the inner ribbed tube 1 has been mentioned;
It goes without saying that the method of the present invention can also be applied to a tube with an inner ribbed surface having 1 to 3 or 5 or more ml markings m on the inner surface of the tube.

The present invention also relates to hot water sampling methods other than the above-mentioned current hot water exploration method,
For example, it can be applied to magnetic flaw detection, etc. 1. As described in detail above, the present invention can be used for internal sound flaw detection of internal ribbed parts, and the 7t can be loosely inserted into a pipe with an inward lip.

The means for holding the number of flaw detection gloves to be pressed against the surface of the helical brocade is moved in the longitudinal direction of the internally ribbed tube while rotating 7', thereby causing the flaw detection gloves to spirally move. Since it scans along the spiral groove, it is possible to detect defects such as seizure defects along the spiral groove formed on the inner surface of the inner ribbed tube. Therefore, the present invention provides an effective means for quality control of internally ribbed tubes.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a tube with internal ribs, FIG. 2 is a longitudinal cross-sectional view, FIG. 3 is a schematic longitudinal cross-sectional view showing the implementation state of the method of the present invention, and FIG. 4 is a W-- A schematic cross-sectional view taken by the N-line; FIG. 5 is a partially enlarged schematic cross-sectional view of a portion where an eddy current flaw detection probe is attached; and FIGS. 6 and 7 are cross-sectional views taken using the method of the present invention. FIG. 2 is a schematic cross-sectional view showing an example. l...Tube with internal ribs 1a...Rip 1b...Spiral groove 2...Mandrel 4...Holder 5...
Eddy current flaw detection probe 6...Compression splash patent applicant Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] 1. The inside of the pipe with internal ribs is loosely inserted into the pipe with internal ribs, and the number of flaws is detected. The inner ribbed surface is configured to scan the hot water sampling probe along the spiral groove by rotating the means for holding the inner ribbed tube in the lengthwise direction of the inner ribbed tube. Flaw detection method for attached pipes.