JPH0798303A - Ultrasonic automatic crack detector - Google Patents

Abstract

PURPOSE:To accurately inspect by automatically turning around a steel pipe without handling an ultrasonic probe. CONSTITUTION:Rotors 3, 4 are installed in brackets 1, 2 fixed on the circumference of a steel pipe P1 so as to be able to concentrically rotate with the steel pipe P1, and gears 7, 8 capable of rotating in the direction of circumference of the steel pipe P1 are fixed to the rotors 3, 4. Ultrasonic proves 22, 23 having a plurality of probe main bodies are installed in an air 15 fixed to the gear 7 so as to interpose a butt welding part W1 of the steel pipe P1 from the direction parallel to a steel pipe line L.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic ultrasonic flaw detector.

[0002]

2. Description of the Related Art Conventionally, ultrasonic flaw detection has been performed on a butt welded portion of a small-diameter thin-walled steel pipe of a boiler tube and a welded portion of a tube plate of a heat exchanger and a heat transfer tube.

Conventionally, for example, in the case of ultrasonic flaw detection of a butt welded portion of a steel pipe, an operator holds the ultrasonic probe in his / her hand and contacts the outer periphery of the steel pipe, and at the same time, the ultrasonic probe is used. Is moved in the circumferential and longitudinal directions, the ultrasonic waves transmitted from the ultrasonic transmitter / receiver are transmitted from the ultrasonic probe to the welded part, and the echoes reflected by the defects or the welding beads are returned to the ultrasonic probe. For example, it is transmitted from a tentacle to a signal processing device through an ultrasonic transmission / reception device and processed, and the processed result is displayed on a monitor or recorded on recording paper and printed out.

Also, when performing ultrasonic flaw detection on the welded portion between the tube plate and the tube of the heat exchanger, the operator holds the ultrasonic probe in his or her hand to make contact with the inner circumference of the tube and The flaw detection is carried out in the same manner as in the case where the butt welded portion of the steel pipe is flaw-detected by moving in the longitudinal direction.

[0005]

However, in the conventional ultrasonic flaw detection, the operator uses the ultrasonic probe to detect the butt welded portion of the steel pipe and the welded portion of the tube sheet and the pipe. Therefore, there is a problem that the inspection is difficult and time-consuming because the work must be carried out and the accuracy of the flaw detection result is not so good.

In view of the above situation, the present invention can automatically perform ultrasonic flaw detection without having to hold the ultrasonic probe in the hand, and can perform the ultrasonic flaw detection quickly and accurately. The purpose is to do so.

[0007]

A first means is a bracket which can be assembled on the outer circumference of a pipe so as to hold the pipe, and a rotating body which is fitted onto the bracket so as to be substantially concentric with the pipe. And a power transmission body attached to the rotating body so as to be substantially concentric with the pipe, and a support member attached to the power transmission body in the longitudinal direction of the pipe with reference to the butt welded portion on the outer circumference of the pipe. A plurality of ultrasonic probes that are mounted so as to be located in the probe main body and have a built-in probe main body, and drive means for rotating the rotating body in the circumferential direction of the tube via the power transmission body. is there.

In the probe body of the first means, the contact surface of the probe body for detecting a defect in the butt welded portion of the pipe and the contact surface of the ultrasonic probe with respect to the outer circumference of the pipe are closely attached to the outer circumference of the pipe. It may be configured by a probe main body for detecting whether or not there is.

A second means is a rotation which is formed so that it can be inserted into the inside of a pipe welded to a tube plate and can be adhered to the inner circumference of the tube and a packing that can be adhered to the front surface of the tube plate on the outer circumference. Body, an ultrasonic probe attached to the rotating body so as to be located between the packings, having a built-in probe body, and capable of contacting the inner circumference of the pipe, and a housing for rotatably supporting the rotating body Position adjustment mechanism installed between the frame and the housing to move the rotor forward and backward in the longitudinal direction of the rotor, drive means for rotating the rotor in the circumferential direction of the tube, and inserting the rotor into the tube. And a means for supplying a medium to the space formed between both packings.

The probe main body in the second means is a refocusing oblique-angle transducer type probe main body for detecting a defect having an inclination and two divisions for detecting a defect having no inclination. It may be configured by a vertical oscillator type probe body.

[0011]

In the first means, the drive means is driven to rotate the support body via the power transmission body, and the ultrasonic probe comes into contact with the outer circumference of the tube to rotate the outer circumference of the tube. For,
Ultrasonic flaw detection of butt welds of pipes is automatically performed, and because multiple ultrasonic probes are provided before and after the welds,
Accurate ultrasonic flaw detection is performed.

The probe body is used to detect whether or not the contact surfaces of the probe body and the ultrasonic probe for detecting defects in the butt welding portion of the pipe are in close contact with the pipe outer periphery. If the probe main body is used for this purpose, it is possible to detect the butt-welded portion with higher accuracy.

In the second means, the rotating body is rotated by driving the driving means, and the ultrasonic probe rotates the inner circumference of the tube. Therefore, the welding portion between the tube and the tube plate is automatically rotated. Ultrasonic flaw detection is performed, and by supplying a medium to the space formed between the packings and adjusting the position of the ultrasonic probe in the longitudinal direction of the rotor with the position adjustment mechanism, accurate ultrasonic flaw detection can be performed. Done.

A probe main body is a refocusing oblique-angle transducer type probe for detecting a tilted defect, and a two-divided vertical oscillator type probe for detecting a non-tilt defect. When the tentacle body is used, the welded portion can be detected with higher accuracy.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 3 show an embodiment of the present invention for ultrasonically flaw-detecting a butt welded portion of a steel pipe. In the drawings, reference numerals 1 and 2 denote radially outward at one end portion in a direction parallel to the axis L of the steel pipe. flange 1a which projects toward, 2a can fitted on and the outer circumference of the steel pipe P ₁ mounted bracket, 3 and 4 are fitted to the bracket 2 so as to be substantially concentric with respect to the steel pipe P ₁ and the steel pipe P
₁ is a rotating body that can rotate in the circumferential direction, 5 and 6 are rotating bodies 3,
Housings attached to the flanges 1a and 2a so as to be fitted onto the outer periphery of the rotor 4, and 7 and 8 are parallel to the steel pipe axis L at the ends of the rotating bodies 3 and 4 opposite to the flanges 1a and 2a. Is a gear mounted via pins 9 and 10 extending to
6a is fitted in annular grooves 3a and 4a provided on the outer circumferences of the rotating bodies 3 and 4, so that the rotating bodies 3 and 4 can be pressed so as not to move in the longitudinal direction of the steel pipe.

Brackets 1, 2, rotating bodies 3, 4, housing
The gears 5, 6 and the gears 7, 8 are steel pipes P. ₁When attached to
Is a semi-circular shape that is divided into two in the circumferential direction so that it has a cylindrical shape
Are formed on the brackets 1, 2 and the housing
1 division of 5 and 6 is parallel to the steel pipe axis L
They are connected by an extending pin 11. And then
The pins 1, 2 and the housings 5, 6 are centered on the pin 11.
Steel that can be opened and closed in the circumferential direction and should be flaw-detected.
Tube P₁When attaching to brackets 1, 2 and housing
Bolting the divided part of the ring 5 and 6 opposite to the pin 11
Is ready to go.

A motor 13 is attached to a bracket 12 attached to the housing 5, and a gear 14 attached to an output shaft of the motor 13 can mesh with the gears 7 and 8. Further, an arm 15 extending parallel to the steel pipe axis L in a direction away from the gears 7 and 8 is attached to a side end portion of the gear 7 opposite to the rotating body 3, and is attached to the arm 15 slidably and fixedly. Attached to the brackets 16 and 17 are rods 18 and 19 that extend in the steel pipe radial direction as viewed from the side and are movable back and forth in the steel pipe radial direction. At the ends of the rods 18 and 19 on the steel pipe side, an axis line is formed. Ultrasonic probes 22 and 23 are swingably attached via pins 20 and 21 that intersect the axis of 19 and extend in the radial direction of the steel pipe P ₁ . 1 and 2, 24 and 25 are ultrasonic probes 2.
The springs 2 and 23 are for pressing the surface of the steel pipe P _{1 with} a constant force.

[0019] Each ultrasonic feeler with ultrasound probe 22 is placed at a predetermined distance to the steel pipe axis L direction parallel to opposite sides of the butt weld W ₁ of the steel pipe P ₁ The contact surfaces of the children 22, 23 facing the steel pipe P ₁ are the steel pipe P ₁
Each of the ultrasonic probes 22 and 23 is formed in an arc shape following the outer circumference of the ultrasonic probe 22, and each of the ultrasonic probes 22 and 23 has three probe main bodies 22a, 22b, 22c, 23a, 23b, which transmit and receive ultrasonic waves.
22c. Each probe body 22a, 22b, 2
3a and 23b have their transmitting and receiving surfaces facing toward the center of the steel pipe P ₁ when viewed from the side and facing the probe bodies 23a, 23b and 2
2a, 22b are arranged in an inclined state with respect to the steel pipe axis L, and the transmitting and receiving surfaces of the probe bodies 22c, 23c are arranged so as to be parallel to the steel pipe axis L so as to face the center of the steel pipe P ₁ . . Matasagu scratches during probe body 22a located on the butt welded portion W ₁ side in, 23a inclination angle of the probe body 22b located away from the welded portion W ₁ butt during testing,
It is formed smaller than the inclination angle of 23b.

Ultrasonic waves are applied to the respective ultrasonic probes 22 and 23 by the respective probe bodies 22a, 22b, 22c, 23a and 23.
b, 23c, and is reflected by a defect or a welding bead, and each ultrasonic probe main body 22a, 22b, 23c, 23a, 23
b, 23c is electrically connected to an ultrasonic transmitter / receiver 26 for receiving the echoes returned, and the echo signal from the ultrasonic transmitter / receiver 26 and the signal from the motor controller 27 are signals provided with a monitor 28a. It can be transmitted to the processing device 28. Further, a drive command signal can be given to the motor 13 from the motor controller 27. In the figure, 29 is a handle and 30 is a signal processing device 28, for example.
It is a recording sheet printed out from a printer provided in the section.

[0021] When testing the butt weld W ₁ of the steel pipe P ₁ is the rotating body 3 is located between the bracket 1 and the housing 5, the rotary body 4 is located between the bracket 2 and the housing 6 Brackets 1, 2 and housing 5,
6 to open the pin 11 as a reference, probe ultrasonic waves from the outer peripheral side of the steel pipe P ₁ bracket 2 on the outer periphery of the steel pipe P ₁ probe 2
2 and 23 are installed so as to face each other with the butt welded portion W ₁ sandwiched therebetween, the brackets 1 and 2 and the housings 5 and 6 are closed around the pin 11, and bolted to fix the brackets 1 and 2 and the housings 5 and 6. the assembled to the outer periphery of the steel pipe P _1, it is contacted with a surface facing the steel pipe P ₁ the outer circumference of the ultrasonic probe 22 to the steel pipe P ₁ circumference.

Next, a drive command signal is output from the motor controller 27 to drive the motor 13 in the normal or reverse direction, and the ultrasonic wave is transmitted from the ultrasonic wave transmitting / receiving device 26 to the ultrasonic probe 22,
23, and ultrasonic flaw detection is started.

Therefore, the motor 13 is driven and the gear 1
The arm 15 rotates normally or reversely via 4, 7, and 8, and the ultrasonic probes 22 and 23 rotate normally or reversely along the outer circumference of the steel pipe P ₁ . When the ultrasonic probes 22 and 23 rotate, ultrasonic waves are transmitted to the probe main bodies 22a, 22b, 23a and 23.
originating from b, bent at the outer peripheral portion of the steel pipe P _1, directed to a directly or steel pipe weld W ₁ butt is reflected by the inner peripheral portion of the P _1.
The ultrasonic waves are reflected by the defect or the welding bead, and are transmitted as echoes from the probe main bodies 22a, 22b, 23a, 23b to the signal processing device 28 via the ultrasonic transmission / reception device 26 and processed. The ultrasonic waves transmitted from the probe main bodies 22c and 23c are reflected by the inner circumference of the steel pipe P ₁ and transmitted as echoes from the probe main bodies 22c and 23c to the signal processing device 28 via the ultrasonic transmission / reception device 26. ,It is processed.

Further, the motor controller 27 gives a drive command signal to the motor 13 and also gives a signal to the signal processing device 28. Therefore, the ultrasonic probe 2 is provided on the monitor 28a.
The circumferential positions and echo heights of the steel pipes 2 and 23 with respect to the steel pipe P ₁ are projected as a waveform, and based on this, the butt welding portion W ₁
The presence or absence and the position of the defect are determined. When there is a defect, a large peak appears in the waveform.

The echoes from the probe main bodies 22c and 23c are projected on the monitor 28a as a linear image as shown by CC1 and CC2, whereby the ultrasonic probes 22 and 23 are displayed on the outer circumference of the steel pipe P ₁ . It is determined whether or not they are in close contact with each other and that ultrasonic waves are being transmitted and received properly. That is,
When the ultrasonic probes 22 and 23 are in close contact with the outer circumference of the steel pipe P ₁ to transmit and receive ultrasonic waves favorably, CC1,
The line of CC2 is a continuous straight line, but if the ultrasonic waves are not well transmitted and received without contact, CC1 and C1
The line C2 is an intermittent line at the portion where the ultrasonic probes 22 and 23 are not in close contact with each other. This is the ultrasonic probe 22,2
This is because the echo of ultrasonic waves does not return in the part where 3 is not in close contact.

The flaw detection result may be displayed on the monitor 28a, or may be read by a floppy disk inserted in the signal processing device 28 or printed out on the recording paper 30 as required.

The gears 7 and 8 rotate to rotate the ultrasonic probe 22,
When 23 makes one round in the normal direction and the reverse direction around the steel pipe P _1, the ultrasonic flaw detection of the butt weld W ₁ at that position is completed.

The ultrasonic probes 22 and 23 are automatically connected to the steel pipe P.
_Since the outer periphery of ₁ is rotated, ultrasonic flaw detection can be performed quickly, and ultrasonic waves can be transmitted and received by the ultrasonic probes 22 and 23 arranged so as to sandwich the butt welded portion W ₁ , and the probe main body 22c , 23c, it is also possible to detect whether or not ultrasonic waves are being transmitted and received satisfactorily by the echoes of the ultrasonic waves. Therefore, ultrasonic flaw detection can be performed with high accuracy.

4 to 6 show another embodiment of the present invention in which the welded portion between the tube plate of the heat exchanger and the heat transfer tube is subjected to ultrasonic flaw detection.

The bearing 34 fitted in the housing 33 includes:
A rotating body 35 having an outer diameter that can be inserted into the heat transfer tube P ₂ welded to the tube plate B is rotatably supported, and a rotating body 3 is supported by a spring 36 in a recess 35 a provided on the outer periphery of the rotating body 35.
5, the ultrasonic probe 3 is urged outward in the radial direction.
7 is inserted so as to be able to advance and retreat in the radial direction of the rotating body 35, so that the outer periphery of the rotating body 35 may be in close contact with the inner periphery of the heat transfer tube P ₂ on the outer periphery on the tip side of the ultrasonic probe 37. The packing 38 made of soft rubber is attached, and the outer periphery of the rotary body 35 on the rear end side of the ultrasonic probe 37 is formed in a U-shape in cross section so that the tip closely contacts the front surface of the tube sheet B. A soft rubber packing 39 is attached.

A gear 40 is integrally provided behind the packing 39 attachment portion of the rotary body 35, and a gear 42 attached to the output shaft of a motor 41 installed in the housing 33 meshes with the gear 40.

A screw shaft 45 is rotatably supported by a bearing 44 fitted in a frame 43 having a handle 43a at the bottom, and a screw portion 45a formed at the tip of the screw shaft 45 is
The housing bracket 46, which is integrally attached to the housing 33, is screwed into a female screw portion 46 a of the housing bracket 46 so as to be parallel to the rotating body 35. A worm wheel 47 provided at the rear end of the screw shaft 45 meshes with a worm 48, and a shaft 49 fitted with the worm 48 is rotatably supported by a bracket 50 attached to the frame 43. An operating knob 51 is attached to one end of the.

A guide rod 52 is attached to the frame 43 in parallel with the screw shaft 45, and the tip end side of the guide rod 52 penetrates the guide hole 46b of the housing bracket 46.

The ultrasonic probe 37, as shown in FIG.
As shown in FIG. 6 and the arc-shaped probe main body 37a of the refocusing oblique-angle transducer type, which makes it possible to detect the defect 53 having the inclination of the welded portion W ₂ by narrowing the ultrasonic beam at the time of forward rotation. Defect 54 that does not have the inclination of the weld W ₂ at the time of reverse rotation
Of the two-divided vertical vibrator type flat plate-shaped probe main bodies 37b, 37c, and the probe main bodies 37b, 37
Probe bodies 37b and 37c so that c do not affect each other
The probe main body 37a is provided with an acrylic resin shielding member 37d interposed therebetween, and the probe main body 37a is arranged such that the concave surface faces the outer circumference of the rotating body 35 and the sound wave axis faces diagonally forward of the outer circumference of the rotating body 35. In the tentacle bodies 37b and 37c, the sonic axis is the welded portion W ₂
They are arranged so as to be diagonally forward or rearward of the rotating body 35 so as to intersect with each other.

To the ultrasonic probe 37, ultrasonic waves are transmitted to the respective probe bodies 37a and 37b, reflected by the defects 53 and 54 and welding beads, and returned via the probe bodies 37a and 37c. The ultrasonic transmission / reception device 55 for receiving the echo is electrically connected, and the echo signal from the ultrasonic transmission / reception device 55 and the signal from the motor controller 56 are transmitted to the signal processing device 57 having the monitor 57a. I'm supposed to get it. Further, the motor controller 56 can supply a drive command signal to the motor 13.

In the figure, reference numeral 58 indicates, for example, the signal processing device 5.
A recording paper printed out from a printer provided at the 7th part, 59 supplies water as an ultrasonic medium to a space 60 surrounded by the packings 38 and 39, the inner circumference of the heat transfer tube P _{2 and the} front surface of the tube plate B at the time of flaw detection. It is a pump for.

[0037] When testing the welded portion W ₂ of the tube plate B and the heat transfer tubes P ₂ is inserted from the front end side of the rotating body 35 with the hand grip 43a of the frame 43 into the heat transfer tube P _2, Position the ultrasonic probe 37 in the vicinity of the welded portion W ₂ and set the packing 38
To the inner circumference of the heat transfer tube P ₂ and the packing 39 to the front surface of the tube sheet B. Further, by rotating the operating knob 51, the worm 48, the worm wheel 47
The screw shaft 45 is rotated via. Then, the housing 33 and the rotating body 35 are integrally moved forward and backward, and the position of the ultrasonic probe 37 in the longitudinal direction of the heat transfer tube P ₂ is finely adjusted.

Next, the pump 59 is driven to move the water into the space 60.
To drive the motor 41 in the normal or reverse direction, and at the same time, the ultrasonic wave is transmitted from the ultrasonic wave transmitting / receiving device 55 to the ultrasonic probe 37.
To start ultrasonic flaw detection.

Therefore, the motor 41 is driven to drive the gear 4
The rotating body 35 is normally or reversely rotated in the circumferential direction of the heat transfer tube P ₂ via 2, 40, and the ultrasonic probe 37 is normally or reversely rotated along the inner circumference of the heat transfer tube P ₂ . Further, when the ultrasonic probe 37 rotates, ultrasonic waves are transmitted from the probe main bodies 37a and 37b, but at the time of forward rotation, the presence or absence of the defect 53 tilted by the ultrasonic waves transmitted from the probe main body 37a. It is inspected, and at the time of reverse rotation, the presence or absence of the non-tilted defect 54 is inspected.

That is, the ultrasonic waves transmitted from the probe main bodies 37a, 37b are reflected by the defects 53, 54 or the welding beads, and are processed as signals from the probe main bodies 37a, 37c via the ultrasonic wave transmitting / receiving device 55. It is transmitted to the device 57 and processed.

Further, the motor controller 56 provides a drive command signal to the motor 41 and also a signal to the signal processing device 57, so that the monitor 57a has a heat transfer tube P _{2 for the} ultrasonic probe 37. The position in the circumferential direction and the echo height are projected as a waveform, and the presence or absence and the position of a defect in the welded portion W ₂ are judged based on this.

The flaw detection result may be displayed on the monitor 57a, or may be read by a floppy disk inserted into the signal processing device 57 or printed out on the recording paper 58 as required.

When the rotating body 35 rotates and the ultrasonic probe 37 makes one revolution in the inner circumference of the heat transfer tube P _{2 in} the forward rotation direction and the reverse rotation direction, the ultrasonic flaw detection of the welded portion W ₂ at that position is completed. Therefore, if necessary, the operation knob 51 is rotated to move the ultrasonic probe 37 forward and backward together with the rotating body 35, and the inspection is performed again according to the above-described procedure.

The ultrasonic probe 37 automatically adjusts the heat transfer tube P ₂
Since the inner circumference of the ultrasonic probe rotates, ultrasonic flaw detection can be performed quickly. If the ultrasonic probe 37 is not in close contact with the inner circumference of the heat transfer tube P ₂ , water will penetrate into that portion. In addition to acting as a medium for propagating ultrasonic waves, the probe main bodies 37a, 37b, 37c to be used are different depending on the shape of the defect, so that accurate ultrasonic flaw detection can be performed.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0046]

According to the ultrasonic automatic flaw detector of the present invention,
In the case of claims 1 and 3, ultrasonic flaw detection can be performed automatically and quickly, and it is possible to perform accurate ultrasonic flaw detection, and in the cases of claims 2 and 4, much higher precision is achieved. It is possible to achieve various excellent effects such as enabling good ultrasonic flaw detection.

[Brief description of drawings]

FIG. 1 is a vertical side view of an embodiment of an automatic ultrasonic flaw detector of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a conceptual diagram including an ultrasonic wave transmission / reception system of the automatic ultrasonic flaw detector shown in FIG.

FIG. 4 is a vertical sectional side view of another embodiment of the automatic ultrasonic flaw detector according to the present invention.

5 is an enlarged view of a portion of an ultrasonic probe used in the automatic ultrasonic flaw detector of FIG. 4, which is a side view showing a state where a tilted defect is detected by a probe body of a lie focus oblique-angle transducer type. It is a figure.

FIG. 6 is an enlarged view of an ultrasonic probe used in the automatic ultrasonic flaw detector of FIG. 4, which is a side view showing a state in which a two-divided vertical transducer type probe body detects a non-tilted defect. Is.

[Explanation of symbols]

1, 2 Bracket 3, 4 Rotating body 7, 8 Gear (power transmission body) 13 Motor (driving means) 14 Gear (driving means) 15 Arm (supporting member) 22, 23 Ultrasonic probe 22a, 22b, 22c, 23a, 23b, 23c
Probe body 33 Housing 35 Rotating body 37 Ultrasonic probe 37a, 37b, 37c Probe body 38, 39 Packing 40 Gear (driving means) 41 Motor (driving means) 42 Gear (driving means) 43 Frame 45 screw Axis (position adjustment mechanism) 46a Female thread (position adjustment mechanism) 47 Worm wheel (position adjustment mechanism) 48 Worm (position adjustment mechanism) 49 Axis (position adjustment mechanism) 51 Knob for operation (position adjustment mechanism) 53, 54 Defect 59 Pump (Means for supplying medium) 60 Space P ₁ Steel tube (tube) P ₂ Heat transfer tube (tube) W ₁ Butt welded portion W ₂ Welded portion (welded) B Tube plate

Claims (4)

[Claims] 1. A bracket that can be attached to the outer circumference of a pipe so as to grip the pipe, a rotating body fitted on the bracket so as to be substantially concentric with the pipe, and substantially concentric with the pipe. As described above, the power transmission body attached to the rotary body and the support member attached to the power transmission body are mounted so as to be positioned in the longitudinal direction of the pipe with respect to the butt welded portion of the outer circumference of the pipe as a reference, and the probe main body. 2. An automatic ultrasonic flaw detector, comprising: a plurality of ultrasonic probes having a plurality of embedded therein; and driving means for rotating the rotating body in the circumferential direction of the tube via the power transmission body. 2. A probe main body for detecting a defect in a butt-welding portion of a pipe and an ultrasonic probe, wherein whether the contact surface of the probe main body with respect to the outer circumference of the probe is in close contact with the outer circumference of the pipe or not. The automatic ultrasonic flaw detector according to claim 1, wherein the ultrasonic flaw detector is constituted by a probe main body for detection. 3. A rotating body, which is formed so that it can be inserted into the inside of a pipe welded to a pipe sheet and can be tightly adhered to the inner circumference of the pipe, and a packing which is tightly adhered to the front face of the pipe sheet on the outer periphery, and the rotating body. An ultrasonic probe that is attached to the body so as to be positioned between the packings and has a built-in probe body, and that can contact the inner circumference of the pipe, and a housing that rotatably supports the rotating body, A position adjusting mechanism installed between the frame and the housing so as to move back and forth in the longitudinal direction, a drive means for rotating the rotating body in the circumferential direction of the pipe, and both packings when the rotating body is inserted into the pipe. An automatic ultrasonic flaw detector, comprising: a means for supplying a medium to a space formed therebetween. 4. A probe main body of an ultrasonic probe for detecting a defect having an inclination, a probe main body of a refocusing oblique-angle transducer type for detecting a defect having an inclination, and a defect main body for detecting a defect having no inclination. Two
4. A divided vertical vibrator type probe main body.
The ultrasonic flaw detector described in.