JP3023641B2 - Composite longitudinal wave bevel probe for ultrasonic flaw detection of pipe welds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite longitudinal wave oblique probe for ultrasonic inspection of a welded portion of a pipe.
It is possible to discriminate between the penetration of the weld and defects with poor penetration, and it is possible to perform flaw detection inspection over the entire area of the weld. In addition, the present invention relates to a composite longitudinal wave oblique probe for ultrasonic inspection of a welded portion of a pipe capable of estimating a defect height.

[0002]

2. Description of the Related Art In the piping of a nuclear or thermal power plant,
If the weld has a defect, the contents may leak out of the defective portion and cause a serious accident, so that careful inspection is performed. That is, the surface of the weld is inspected for appearance,
The inside of the weld is subjected to a nondestructive inspection by a radiation or ultrasonic inspection test. In the ultrasonic inspection of pipes, there is a margin at the welded portion, so that the oblique inspection is generally applied. As a probe to be used, a single element type shear wave bevel probe or a dual element type shear wave bevel probe is generally used. Next, with reference to FIGS. 5 and 6, a conventional two-element transverse wave oblique angle probe will be described.

[0003] As shown in FIG.
In a casing 101, a transmitting unit 103 and a receiving unit 104 of ultrasonic waves separated by a sound absorbing material 102 are arranged side by side with respect to a flaw detection direction. The transmitting unit 103 is provided with a transmitting wedge 105 and a flat transmitting oscillator 106 attached to the transmitting wedge 105. The receiving unit 104 is provided with a receiving wedge 107 and a receiving wedge 107. A flat receiving oscillator 108 is provided. The transmitting oscillator 106 and the receiving oscillator 108 are provided at a slight angle in a mountain shape so that the focal point a of the transmission and reception of the ultrasonic wave is at a certain depth obliquely forward from the flaw detection surface of the pipe 109. The lower surfaces of the transmitting and receiving wedges 105 and 107 are flat. For example, a cylindrical pipe 109 as shown in FIG.
When the butt weld 110 is subjected to ultrasonic inspection, a couplant such as grease is applied to the end of the pipe 109 on the side of the butt weld 110, and the lower surface of the angle beam probe 100 is applied to this applied portion. By moving the oblique probe 100 back and forth while moving it in the direction of the arrow in the figure, an ultrasonic flaw inspection of the butt weld 110 is performed. That is, an ultrasonic wave is generated from the transmitting oscillator 106 to which the pulse voltage is applied, and the ultrasonic wave penetrates the transmitting side wedge 105, enters the pipe 109 from the flaw detection surface of the pipe 109, and is emitted obliquely forward. Is done. If the butt weld 110 has a defect of poor penetration, the defect echo reflected on the defect 111 passes through the receiving wedge 107 from the pipe 109 and vibrates the receiving oscillator 108. As a result, a defective echo is detected.

[0004]

However, the conventional angle beam probe for ultrasonic flaw detection 100 is temporarily provided with a pipe 109.
Even if good butt welding is performed, if an inner surface of the pipe 109 has a backside wave that is a protrusion of the weld metal, the ultrasonic wave from the transmitter 103 is reflected on the backside surface, This reflected echo was sometimes mistaken for a defective echo, and therefore the backwash and the defective portion 111 having poor penetration could not be distinguished well. Also, the conventional angle beam probe 100
As described above, the transmitting unit 103 and the receiving unit 104 are arranged side by side in the lateral direction of the oblique probe 100, and the lower surfaces of the transmitting and receiving wedges 105 and 107 are flat. In contact with the surface of the pipe 109 is the sound absorbing material 102 at the center of the lower surface of the bevel probe 100 which does not contribute to the transmission and reception of the ultrasonic wave at all. For this reason, ultrasonic waves are transmitted and received with ineffective effects through the thick couplant layer such as the grease, so that the S / N ratio of the oblique probe 100 is reduced. The present invention has been made in view of such circumstances, it is possible to distinguish between the penetration of the weld and the defect of poor penetration, and also can perform flaw detection inspection over the entire area of the weld,
Moreover, it is an object of the present invention to provide a composite longitudinal wave oblique probe for ultrasonic flaw detection of a welded portion of a pipe capable of estimating a defect height.

[0005]

According to the present invention, there is provided a semiconductor device comprising:
The combined longitudinal wave bevel probe for ultrasonic flaw detection of a pipe weld described in the description is a transmitting section having a flat transmitting transducer attached to a transmitting wedge, and a flat plate attached to a receiving wedge. A receiving unit having a receiving vibrator, and a transmitting / receiving unit having a flat transmitting / receiving vibrator in which the transmitting unit and the receiving unit are arranged in a flaw detection direction and attached to a transmitting / receiving wedge. The receiving section and the transmitting / receiving section are each partitioned by a sound absorbing material, and the transmitting / receiving section is arranged on the front side in the flaw detection direction from the transmitting section and the receiving section, and these are integrally housed in a casing.

[0006]

In the ultrasonic flaw detection using the composite longitudinal wave oblique probe for ultrasonic flaw detection of a pipe weld according to the first aspect, for example, a flaw detection surface near a butt weld of an inspection object is used. If necessary, apply a couplant such as grease, and apply ultrasonic inspection for the welded part while applying the lower surface of the compound angle beam probe to this coated part. When an ultrasonic wave is emitted and a defect having poor penetration is reflected, the defect is reflected from the defect and returns to the receiving unit of the probe as a defect echo. On the other hand, ultrasonic waves are also emitted into the inspection object from the transmission / reception unit on the front row in the flaw detection direction, and similarly, ultrasonic waves hitting the defective part with poor penetration are reflected and received by the transmission / reception unit. Since the ultrasonic waves that hit the waves escape to the outside and hardly return to the transmitting and receiving unit,
If both the transmitting and receiving unit receives a large reflected echo, it is recognized as a defective part with poor penetration, and if only the receiving unit receives a large echo and the transmitting and receiving unit rarely receives It is recognized as Uranami.
In particular, in the composite longitudinal wave oblique probe for ultrasonic flaw detection of a pipe welded part according to claim 2, the receiving part and the transmitting part are arranged before and after the flaw detection direction, for example, behind the probe. The ultrasonic wave emitted from the transmitting unit disposed at the position becomes a defect echo and returns from the defective portion to a receiving unit disposed, for example, in front of the probe. In this case, since the ultrasonic wave is directly transmitted to and received from the inspection object from the combined angle beam probe, the flaw detection sensitivity is improved, and the transmission transducer and the reception transducer can be brought closer. This makes it possible to reduce the angle of transmission and reception with respect to the focal point of transmission and reception, thereby increasing the flaw detection depth. The effect is promoted by shortening the transmitting / receiving vibrator in the flaw detection direction and lengthening the vibrator in the direction perpendicular thereto.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is an enlarged sectional view in the flaw detection direction showing a use state of a combined longitudinal wave oblique probe for ultrasonic flaw detection of a pipe welded portion according to one embodiment of the present invention, and FIG. FIG. 3
Is a side view showing the same use state, and FIG. 4 is an enlarged sectional view in the flaw detection direction showing the other use state.

As shown in FIG. 3, a composite longitudinal wave oblique probe 10 for ultrasonic inspection of a welded portion of a pipe according to an embodiment of the present invention is a butt of pipes 11 as an example of an inspection object. A flaw detection inspection of the welded portion 11a is performed. Figures 1 and 2
As shown in the figure, a composite longitudinal wave bevel probe 10 for ultrasonic flaw detection of a pipe welded portion is provided in a casing 12 made of stainless steel having a long front and rear direction and a pair of front and rear parts inclined obliquely forward and downward. The transmitting / receiving unit 14, transmitting unit 15, and receiving unit 16 of the ultrasonic wave partitioned by the sound absorbing material 13
In front of the angle beam probe 10 and the transmission section 15 with the angle beam probe 10
, The receiving unit 16 is arranged at the center of the oblique probe 10. These sound absorbing material 13 and transmitting / receiving unit 1
4. The transmission unit 15 and the reception unit 16
It has a total length of two lateral widths.

The transmitting / receiving section 14 includes a transmitting / receiving wedge 17 made of a synthetic resin such as an acrylic resin, and a flat transmitting / receiving vibrator 18 attached to a rear inclined surface 17a of the transmitting / receiving wedge 17 which is inclined downward. The receiving unit 16 has a receiving wedge 19 made of the same synthetic resin as above.
And the rear inclined surface 1 that is inclined downward of the receiving side wedge 19.
The transmitting unit 15 includes a transmitting wedge 21 made of the same synthetic resin as described above, and a rear inclined surface 21a that is inclined downward from the transmitting wedge 21. Transmission oscillator 2 mounted on the plate
Two. Transmitting / receiving vibrator 18, receiving vibrator 20,
The transmitting vibrator 22 is a known vibrator in which electrodes are fixed to both surfaces of a vibration plate made of, for example, lead zircon titanate. In addition, the lower surfaces of the transmitting and receiving wedges 17, the receiving wedges 19, and the transmitting wedges 21 are flat surfaces, but are not limited thereto, and may be curved surfaces along the outer peripheral surface of the pipe 11, for example.

Here, as shown in FIG. 1, the inclination angles of the rear inclined surfaces 17a, 19a, and 21a correspond to the angles of emission of the ultrasonic waves emitted from the transmission / reception oscillator 18 and the transmission oscillator 22, respectively. The angle of inclination of the reflected echo of the ultrasonic wave becomes the angle θ1, and the focal point of each transmission / reception is inclined so that it can be located slightly in front of the flaw detection part or the flaw detection part. Specifically, the inclination angle θ1 is 20 to 30 degrees, preferably 21 to 27 degrees, and the longitudinal waves of ultrasonic waves emitted from the transmitting / receiving vibrator 18 and the transmitting vibrator 22 (see the solid line in FIG. The incident angle θ2 entering the inside is 70 to 80 degrees,
Preferably, the angle is 72 to 78 degrees.
The incident angle θ3 at which the transverse wave (see the chain line in the figure) of the ultrasonic wave emitted from 2 enters the pipe 11 is 30 to 40 degrees, preferably 32 to 38 degrees.

Next, the operation of the composite longitudinal wave oblique angle probe 10 for ultrasonic inspection of a pipe weld according to the present invention will be described. When an ultrasonic inspection is performed on the butt-welded portion 11a of the cylindrical pipe 11 as shown in FIG. 3, a couplant such as grease is applied to the butt-welded portion 11a of the pipe 11.
The end portion on the a side is applied, and the oblique probe 10 is moved in the direction indicated by the arrow in FIG. Perform ultrasonic flaw inspection.

That is, as shown in FIG. 1, an ultrasonic wave is periodically generated from a transmission oscillator 22 to which a pulse voltage is applied, and the ultrasonic wave passes through a transmission-side wedge 21 and passes through a pipe 1.
1 and enters into the pipe 11 from the flaw detection surface, and is fired toward a flaw detection portion obliquely forward. If there is a defect of poor penetration in the butt weld portion 11a, the defect echo reflected on the defect portion 11b is transmitted from the pipe 11 through the receiving wedge 19 to the receiving vibrator 20, and is converted into an electric signal. Is detected. At this time, there are three main paths of the ultrasonic wave: first and second paths A and B, which are longitudinal wave paths, and a third path C, which is a transverse wave path. First route A
Is a path extending from the ultrasonic wave incident position a of the pipe 11 to the position b of the defective portion 11b, the position c of the inner surface of the pipe 11, and the position d at which the ultrasonic wave is taken into the receiving unit 16, and the second path B
Is a path leading to the incident position a, the position b of the defective part 11b, and the position d to be taken into the receiving unit 16, and the third path C
Are the incident position a, the position e of the inner peripheral surface of the pipe 11, the position f of the butt welded portion 11a, and the position d to be taken into the receiving portion 16.
It is a route to reach. As described above, solid arrows in the drawing indicate longitudinal waves and dashed arrows indicate transverse waves, and longitudinal waves and transverse waves are mutually mode-converted at predetermined positions shown in the figure.

On the other hand, as shown in FIG. 1, an ultrasonic wave is also emitted into the pipe 11 from the transmission / reception unit 14 on the front row side in the flaw detection direction, and similarly, the ultrasonic wave hitting the defective portion 11b with poor penetration is reflected. Received by the transmission / reception unit 14. At this time, a transverse wave is used for flaw detection, and the other longitudinal wave escapes outward as shown in FIG. The specific path D of the transverse wave is defined by
Is the path to the position h of the inner surface, the position i of the defective portion 11b, and the incident position g.

Next, referring to FIG. 4, a description will be given of a path of an ultrasonic wave in the pipe 11 which has a back seam 11c and is subjected to good butt welding by using the composite angle beam probe 10 of the embodiment. In this case, the path E and F of the longitudinal wave are illustrated in the path description of the ultrasonic wave of the transmission unit 15, and the path of the ultrasonic wave in the transmission / reception unit 14 is described as described above because the longitudinal wave escapes outward as described above. Only the path G of the shear wave is shown. The path E of the longitudinal wave in the transmission unit 15 is a path from the incident position a of the ultrasonic wave on the pipe 11 to the position j in the front part of the back wave 11c, which is reflected in the opposite direction and reaches the capture position d in the transmission unit 16. , And the path of longitudinal wave F is
This is a path leading to an incident position a, a position j at the front of the back wave 11c, a position k at the rear of the back wave 11c, and an incident position g. On the other hand, the path G of the shear wave in the transmission / reception unit 14 is a path that escapes outward through the incident position g and the position m of the rear end of the back wave 11c. That is, when the butt welding portion 11a has a backside wave 11c, the ultrasonic waves emitted from the transmitting unit 15
6, the ultrasonic waves emitted from the transmission / reception unit 14 escape to the outside and are not received by the transmission / reception unit 14.

From the above, according to the conventional means, the piping 11
Even if welding is performed well, if a backwash 11c is generated on the inner surface of the pipe 11, the transmission unit 15
There is a possibility that the ultrasonic wave from the target is reflected and this reflected echo is mistaken for a defective echo. However, according to the present means, when both the transmitting / receiving unit 14 and the receiving unit 16 receive a large reflected echo,
It can be recognized as a defective portion 11b with poor penetration, and if only the receiving unit 16 receives a large echo and the transmitting / receiving unit 14 receives little, it can be recognized as a back wave 11c. Further, in the compound angle beam probe 10, since the transmitting unit 15 and the receiving unit 16 are arranged before and after in the flaw detection direction, the ultrasonic waves emitted from the transmitting unit 15 in the rear row become defect echoes and become defective echoes. 11b returns to the receiving unit 16 in the front row. In this case, since the ultrasonic wave is directly transmitted to and received from the pipe 11 from the compound-type oblique probe 10, the flaw detection sensitivity is improved, and the transmission transducer 22 and the reception transducer 20 can be brought closer. Thereby, the angle of transmission / reception with respect to the focal point of transmission / reception can be reduced, so that the flaw detection depth effective range in the plate thickness direction can be expanded. Then, the transmitting and receiving vibrators 20, 2
By shortening 2 in the flaw detection direction and lengthening it in a direction perpendicular to the flaw detection direction, the above-described action is promoted.

The present invention is not limited to this embodiment, and includes any design changes within the scope of the present invention. For example, in the embodiment, the transmission unit and the reception unit arranged behind the transmission / reception unit in the flaw detection direction are arranged before and after the flaw detection direction. However, the present invention is not limited to this. Parts may be arranged on the left and right in the flaw detection direction. In addition, the arrangement of the receiving part and the transmitting part of the compound angle beam probe may be reversed, and in order to improve the flaw detection sensitivity, the mounting surface of the receiving wedge of the receiving side wedge is provided on the receiving side. It may be slightly inclined.

[0017]

According to the first aspect of the present invention, there is provided a composite longitudinal wave oblique probe for ultrasonic inspection of a welded portion of a pipe, wherein the transmission and reception units have transmission and reception transducers in the inspection direction from the transmission unit and the reception unit. Therefore, when both the transmitting and receiving unit and the receiving unit receive a large reflected echo, it can be recognized as a defective part with poor penetration, and only the receiving unit receives a large echo, and the transmitting and receiving unit is almost If not received, it can be recognized as a backwash, which makes it possible to discriminate between a backwash of a welded portion and a defect of poor penetration. In particular, in the composite longitudinal wave bevel probe for ultrasonic flaw detection of a welded portion of a pipe according to the second aspect, the flaw detection in the welded portion is performed from the transmitter disposed behind the bevel probe, for example. The ultrasonic wave is emitted toward the part, and if there is a defect, it returns as a defect echo and returns to the receiver, for example, placed in front of the angle beam probe, so the flaw detection effective range is widened and the Defects can be detected without moving the child back and forth. In addition, since the receiver and transmitter are arranged before and after the oblique probe, even if the inspection object has a curvature, the center part of the wedge of the probe can directly contact the inspection object to perform the inspection. Thereby, the SN ratio can be improved.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view in a flaw detection direction showing a use state of a combined longitudinal wave oblique probe for ultrasonic flaw detection of a pipe welded portion according to one embodiment of the present invention.

FIG. 2 is a sectional view in the same width direction.

FIG. 3 is a side view showing the same use state.

FIG. 4 is an enlarged sectional view in a flaw detection direction showing another usage state.

FIG. 5 is a schematic enlarged front view showing a use state of a composite longitudinal wave oblique angle probe for ultrasonic flaw detection of a pipe weld according to conventional means.

FIG. 6 is a side view showing the same use state.

[Explanation of symbols]

10: Composite longitudinal wave oblique probe for ultrasonic inspection of pipe welds, 11: pipe, 11a: butt weld, 11
b: defective part, 11c: Uranami, 12: Casing, 13:
Sound absorbing material, 14: transmitting / receiving unit, 15: transmitting unit, 16: receiving unit, 17: transmitting / receiving side wedge, 17a: rear inclined surface, 1
8: transmission / reception vibrator, 19: reception side wedge, 19a: rear inclined surface, 20: reception vibrator, 21: transmission side wedge, 21
a: rear inclined plane, 22: transmitting oscillator

Continued on the front page (72) Inventor Masayuki Imahashi 4-10-13, Ibori, Kokurakita-ku, Kitakyushu-shi, Fukuoka Prefecture Inside of New Japan Non-Destructive Inspection Co., Ltd. (72) Inventor Kunichi Watanabe 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Address Toshiba Corporation Yokohama Office (72) Inventor Kunio Kawamata 3-7-1 Nishi-Shimbashi, Minato-ku, Tokyo Toshiba Plant Construction Corporation (56) References JP-A-51-7987 (JP, A) 1986-54266 (JP, U) JP-A 3-80362 (JP, U) JP-A 62-44255 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 29 / 00-29/28

Claims (2)

(57) [Claims] 1. A transmitting section having a flat transmitting oscillator attached to a transmitting wedge, a receiving section having a flat receiving oscillator attached to a receiving wedge, the transmitting section and the receiving section. And a transmission / reception unit having a plate-shaped transmission / reception vibrator attached to the transmission / reception-side wedge, the transmission unit, the reception unit, and the transmission / reception unit being partitioned by a sound absorbing material. The unit is disposed on the front side in the flaw detection direction from the transmission unit and the reception unit,
A combined longitudinal wave angle beam probe for ultrasonic flaw detection of pipe welds, wherein these are housed integrally in a casing. 2. The combined longitudinal wave oblique probe for ultrasonic flaw detection of a pipe weld according to claim 1, wherein the receiving section and the transmitting section are arranged before and after in the flaw detection direction.