JP2003057215A - Automatic ultrasonic flaw detection method and apparatus of welded section - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an automatic ultrasonic flaw detection method and an automatic ultrasonic flaw detection apparatus of welded sections for surely detecting flaws and reducing the flaw detection time by combining a pulse reflection method and a TOFD method. SOLUTION: In the automatic ultrasonic flaw detection method of a welded section, the pulse reflection method for performing the vertical square scanning of a probe, in a direction along a welded line and a direction at right angles to the welded line, and the TOFD system for scanning the probe in a direction along the welded line are combined so as to be compound flaw detection. In the automatic ultrasonic flaw detection apparatus of the welded section, a rail is installed in parallel with the welded line, a body that can drive while being guided by the rail is installed, a movable shaft that can slide at right angles to the driving direction of the body, a fixed shaft that is extended in the same direction are provided, a probe for pulse reflection is fitted to the movable shaft, and the probe for TOFD is fitted to the fixed shaft.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pulse reflection method and a TOFD method (Time Of Flight Diff).
The invention relates to an automatic ultrasonic flaw detection method and apparatus for a welded portion in combination with a traction.

[0002]

2. Description of the Related Art In recent years, in the case of installing a steel bridge, in-situ welding of bridge steel members including an extremely thick plate is frequently used in order to rationalize the installation and reduce the cost. On the other hand, it is required to improve the on-site quality control system for civil engineering structures, and in particular, it is necessary to develop appropriate and reliable on-site inspection technology for steel welded parts.

Conventionally, non-destructive inspection techniques for steel materials have been
X-ray inspections performed on steel welded structures have been the mainstream.
However, X-ray inspection has many inconveniences when used for in-situ welding inspection, in that there are many restrictions in terms of equipment and handling, and the detection capability of thick plate welds is extremely reduced due to the problem of penetrating power. .

On the other hand, the automatic ultrasonic flaw detection technique can be easily used in the field because it can be inspected with a simple facility, and has a high flaw detection capability even for thick plates. The application is expanding as an inspection technology. Several methods have been proposed for this automatic ultrasonic flaw detection technique, and among them, the pulse reflection method, which has high recording property and high reliability, is often used for bridge inspection.

The pulse reflection method is a method in which an ultrasonic beam is applied to the welded portion to detect a bounce echo, and it is determined that the strongest echo that exceeds the darkness value is due to a defect and the position thereof is determined. There are a one-echo method of recording, a two-echo method of recording two peak echoes exceeding a darkness value, and an all-echo method of determining and recording a defect position from all echoes exceeding a darkness value.

In the full echo method, although echo data is recorded and analyzed over the entire welded portion, it takes time to make a decision, but the decision accuracy is high, and the result can be checked easily and the reliability is high. However, it is generally difficult for the pulse reflection method to accurately confirm the defect size due to the influence of the spread of the ultrasonic beam. Further, although the determination result shows the distribution of echoes exceeding the darkness value, this distribution appearing in the output image is easily misunderstood as the shape of the defect.

Further, in this flaw detection method, in order to specify the position in the width direction of the welding line when scanning along the welding line, the basic method is parallel scanning (vertical rectangular scanning) which also scans in the direction perpendicular to the welding line. Therefore, it takes time to detect flaws in the entire welded portion. Further, the pulse reflection method cannot accurately obtain defect height information, and thus cannot evaluate fatigue life, and has a drawback that it is difficult to evaluate damage degree when applied to inspection of an existing bridge.

In contrast to this pulse reflection method, a TOFD flaw detection method (diffraction wave time-of-flight analysis method) in which an ultrasonic beam is transmitted to a welded portion so as to be transmitted and a diffraction wave of ultrasonic waves at a defective portion is received and detected ). This TOFD method has a feature that the position and height of the defect in the depth direction can be determined because the ultrasonic wave diffracted at the defect is detected, and the flaw detection can be performed only by scanning parallel to the welding line. Therefore, the flaw detection time can be shortened.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain an automatic ultrasonic flaw detection method and apparatus which can be applied to non-destructive inspection of in-situ welding, have high flaw detection accuracy and can shorten flaw detection time.

[0010]

An automatic ultrasonic flaw detection method for a welded portion, which is a pulse reflection method in which a probe can be scanned in a rectangular shape in a direction along a welding line and a direction perpendicular to the welding line, TO that allows the probe to scan in the direction along the welding line
Combined with the FD method, the composite flaw detection is performed. Also, T
Rough flaw detection was performed by the OFD method, and the defect portion detected by the TOFD method was narrowed down to perform the flaw detection by the pulse reflection method.

In an automatic ultrasonic flaw detector for a welded part, a rail is laid along a welding line, and a main body is provided which is guided by the rail and can run parallel to the welding line.
A movable shaft slidable in the direction perpendicular to the traveling direction and a fixed shaft projecting in the same direction are provided, a pulse reflection probe is attached to the movable shaft, and a TOFD probe is mounted on the fixed shaft. I put it on.

Further, the movable shaft and the fixed shaft can be provided so as to project to the left side and the right side of the main body, and the pulse reflection probe and the TOFD probe are arranged on the left side or the right side in the traveling direction of the main body. I was allowed to do it. Further, a rail is laid along the welding line, a main body that is guided by the rail and that can run parallel to the welding line is provided, and a movable shaft that is slidable in a direction perpendicular to the running direction is provided on the main body. It is also characterized in that a probe for pulse reflection and a probe for TOFD are mounted on the movable shaft.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a schematic plan view of an automatic ultrasonic flaw detector for welding parts according to the present invention, FIG. 2 is a side view taken along the arrow Y1 in FIG. 1, and FIG. 3 is a side view taken along the arrow Y2 in FIG.
FIG. 4 is a front view taken along the arrow X in FIG. Further, FIG. 5 is an explanatory diagram showing a scanning state of the probe.

First, the device will be described. 1 shows the welding line on the welded steel plate. Reference numeral 2 denotes a traveling rail that is installed on the welded steel plate in parallel along the welding line 1.
Is held by a rail frame 4 attached to a magnet 3 installed on a welded steel plate. The traveling rail 2 is mounted on the rail frame 4 in the field through a fitting type rail, and fixed by pinning at a predetermined position.

On the upper surface of the traveling rail 2, a traveling rack 5 is provided.
Are provided so as to extend in the length direction of the traveling rail 2, and traveling guide bars 6 are provided on the left and right side surfaces of the traveling rail 2 so as to extend in the longitudinal direction of the traveling rail 2. . Reference numeral 7 denotes a main body, which is mounted on the traveling rail 2 so as to be capable of traveling.

The main body 7 has a pinion 8 that meshes with the traveling rack 5 provided on the upper surface of the traveling rail 2 and a guide roller 9 that engages with the traveling guide bars 6 provided on the left and right side surfaces of the traveling rail 2. Have Therefore, when the pinion 8 is driven, the guide roller 9 causes the traveling guide bar 6 to move.
The main body 7 travels on the traveling rail 2 in parallel with the welding line 1 in a state of being guided by. Reference numeral 10 is a traveling motor.

A movable shaft 11 is provided with sliding guide bars 12 on both side surfaces in the lengthwise direction. The sliding guide bars 12 are engaged with sliding guide rollers 13 provided on the main body 7. The sliding guide roller 13 is held in a state of being inserted from the width direction of the main body 7 in a combined state.
It is slidable in the same direction, that is, in the direction perpendicular to the welding line 1 by being guided by the.

Numeral 14 is a sliding rope for the movable shaft 11, which is wound around a wheel 15 mounted on the main body 7 and has both ends attached to both ends of the movable shaft 11. Therefore, when the wheel 15 is rotated in the normal or reverse direction at the set rotational speed, the sliding rope 14 causes the movable shaft 11 to move to the welding line 1.
It can be slid for a predetermined stroke in a direction perpendicular to. Reference numeral 16 is a sliding motor, and 17 is a guide sheave of the sliding rope 14.

Reference numeral 19 denotes a fixed vertical axis, and a fitting type rail is formed on the lower surface thereof, and is fixed to a holding portion 18 mounted at the tip of the movable shaft 11 with a screw at a predetermined position. 20
Is a probe frame, and includes a probe guide rail 21 slidably held on the fixed longitudinal axis 19, and a probe arm 23 slidably held on the probe guide rail 21. It is composed of

The probe guide rail 21 has a fixed vertical axis 19
It is fitted and held in the fitting type rail of No. 1, is slidable parallel to the welding line 1 while being guided by the fixed vertical axis 19, and is fixed by screwing at a predetermined position. A guide bar 22 is provided on the lower surface of the probe guide rail 21. The probe arm 23 is attached through the guide bar 22, and the welding line 1
It is slidable in a direction at right angles to and is fixed by adjusting the mounting position.

Reference numeral 24 is a pulse reflection probe. The pulse-reflecting probe 24 is held by the probe arm 23 via a probe holder axially connected to the probe arm 23 so that the probe height is adjusted and fixed. It should be noted that the two probe arms 23 mounted can be made to cooperate with each other by using a rope mechanism or a screw shaft mechanism so as to be brought closer to each other by a handle operation or the like, and brought into contact with or separated from each other.

A caster is attached to the bottom surface of the pulse reflection probe 24, and when set, the height of the caster is adjusted so as to contact the welded steel plate, and the probe is fixed to the probe arm 23. To be done. Therefore, the pulse reflection probe 24 moves smoothly along with the movement of the probe arm 23.

The configuration including the above-described pulse reflection flaw detector 24 is well known in the art. In the present invention, a TOFD probe is added to this structure, and the added structure will be described below. Reference numeral 25 denotes a fixed shaft having a fitting type rail 26 on the lower surface, which is hung on the main body 7,
It is fixed in a state that it projects from the main body 7 in the direction at a right angle. The overhang length can be adjusted, and when the overhang length is adjusted, it is fixed by screws.

Reference numeral 27 denotes a probe arm, which has a fixed shaft 25.
The fitting type rail 26 is fitted and slidably mounted, and the mounting position is adjusted and screwed and fixed. 28 is TO
It is a probe for FD. The TOFD probe 28 is held on the probe arm 27 via a probe holder axially connected to the probe arm 27 so as to be fixed by adjusting the mounting height.

When the transmitting and receiving probes of the TOFD probe 28 are positioned at a predetermined flaw detection position with the welding line 1 in between, the probe arm 27 is fixed to the fixed shaft 25. ing. A caster is attached to the bottom surface of the TOFD probe 28, and the height of the caster is adjusted so that the caster comes into contact with the welded steel plate and the caster arm 27 is fixed to the probe arm 27. Therefore, the TOFD probe 28 moves smoothly along with the movement of the probe arm 27.

Incidentally, the holding portion 18 of the movable shaft 11 described above.
Can be fixed to the other end side of the movable shaft 11, that is, to the left end in the drawing. In this case, the fixed vertical axis 19, the probe guide rail 21, the probe arm 23, and the pulse reflection probe 24.
Will be arranged on the left side of the main body 7 in the drawing. Similarly, the fixed shaft 25 can also be fixed by protruding to the left of the main body 7,
In this case, the probe arm 27 and the TOFD probe 28
Is also arranged on the left side of the main body 7 in the drawing.

That is, in the illustrated example, the traveling rail 2 is laid on the left side of the welding line 1, the main body 7 is mounted on the rail 2, and the movable shaft 11 and the fixed shaft 25 project to the right side of the main body 7 for flaw detection. It is supposed to do. On the other hand, depending on the position of the welding line 1 on the welded steel plate, the traveling rail 2 is laid on the right side of the welding line 1, the main body 7 is mounted on this, and the movable shaft 11 and the fixed shaft 25 are projected to the left side of the main body 7. It is also possible to detect flaws. Incidentally, reference numeral 29 in the drawing denotes a cover of the main body 7.

The configuration of the present invention is as described above. Next, the flaw detection operation will be described. First, the magnet 3 is installed along the flaw detection position, and the traveling rail 2 is laid on the magnet 3 via the rail frame 4 in parallel with the welding line 1. Then, the main body 7 is mounted on the traveling rail 2. The main body 7 can travel by meshing between the pinion 8 and the traveling rack 5, and is guided along the traveling rail 2 by the engagement of the traveling guide bar 6 and the guide roller 9.

When the main body 7 is mounted, the movable shaft 11 is inserted from the side of the main body 7 so that the sliding guide bar 12 fits into the guide roller 13, and the movable shaft 11 is set. And fix it on the main body 7. Fixed shaft 25
In this case, the probe arms 27 are fitted to the fitting type rails 26 and arranged on both sides of the welding line 1, and the positions thereof are adjusted and fixed. A holder holding a TOFD probe 28 is axially attached to the probe arm 27, and the height is adjusted and fixed.

A holding portion 18 is attached to the movable shaft 11, and a fixed vertical axis 19 is fixed. Then, on the fixed vertical axis 19,
The probe frame 2 is fitted to the fitting type rail on the lower surface thereof.
Wear 0. The probe frame 20 is located at a position corresponding to the flaw detection direction, for example, in FIG. 1, the upper end of the fixed vertical axis 19 is used for the upper flaw detection, and the lower end of the fixed vertical axis 19 is used for the lower flaw detection. Position and fix.

Then, the probe arm 23 is mounted through the guide bar 22 of the probe guide rail 21, and the position is adjusted and fixed. A holder holding a pulse reflection probe 24 is axially attached to the probe arm 23, and the height is adjusted and fixed. In this state, preparation for flaw detection is completed, and flaw detection operation is performed from an operation panel (not shown). Also,
The flaw detection result is transmitted to the operation panel by the flaw detection cable and displayed on the same screen on the panel.

Since the pulse reflection method and the TOFD method are combined, the flaw detection modes include pulse reflection alone, TOFD alone, and composite of pulse reflection and TOFD.
You can detect flaws in the mode. FIG. 5 shows the scanning method.
In the pulse reflection method, parallel scanning is performed in the direction along the welding line 1 and the direction perpendicular to the welding line 1.

Therefore, the traveling motor 10 is intermittently driven, and the main body 7 is intermittently driven. Then, every time the main body 7 is stopped, the drive motor 16 of the sliding rope 14 is alternately rotated in the forward and reverse directions to move the movable shaft 11 in and out by a predetermined stroke. As a result, as shown in FIG.
4 is to perform parallel scanning. When the TOFD is used alone, it is not necessary to perform parallel scanning, so the main body 7 is made to continuously run.

When the flaw detection is performed in the combined mode of pulse reflection and TOFD, the flaw detection result is displayed on the same screen.
You can see both data side by side. For example, TOFD corresponding to a flaw detected by the pulse reflection method
By checking the data of the method, it is possible to confirm the depth of scratches and to detect welding defects more accurately.

Further, since the height of the flaw in the depth direction can be accurately confirmed by the TOFD method, the degree of fatigue damage of the flaw can be evaluated and it can be applied to the inspection of the existing bridge. Further, if the TOFD method is used to perform the rough flaw detection rapidly and the flaw detection range of the pulse reflection method is narrowed according to the result, that is, the flaw detection is performed to the defect portion detected by the TOFD method, the flaw detection is performed by the pulse reflection method. The flaw detection time can be shortened.

In the TOFD type flaw detection, T
The parallel scanning of the OFD probe 28 does not cause any inconvenience to the detection function. Therefore, it is possible to mount the TOFD probe 28 together with the movable shaft 11.

For example, in the illustrated apparatus, the movable shaft 1
The TOFD probe frame similar to the pulse reflection probe frame 20 is fitted to the fitting type rail of the fixed vertical axis 19 fixed to 1, and the pulse reflection probe 24 and the TOFD probe are fitted. Be sure to attach it together with 28.

Even in this case, since it is not necessary to perform parallel scanning when detecting flaws in the TOFD only mode, the movable shaft 11 is not moved in and out, and the main body 7 is allowed to continuously run.

[0039]

According to the present invention, the pulse reflection method is combined with the TOFD method to perform automatic ultrasonic flaw detection. Therefore, depth information can be obtained in addition to the position information of the welding defect, and the welding defect can be further detected. It became possible to evaluate accurately. Further, it has become possible to shorten the time required for flaw detection of welding defects.

[Brief description of drawings]

FIG. 1 is a plan view of an ultrasonic flaw detector according to the present invention.

FIG. 2 is a side view taken along the arrow Y1 of FIG.

FIG. 3 is a side view taken along the arrow Y2 of FIG.

FIG. 4 is a front view taken along arrow X in FIG.

FIG. 5 is a diagram showing a scanning method.

[Explanation of symbols]

1 Welding line 2 Traveling rail 3 Magnet 4 Rail frame 5 Traveling rack 6 Traveling guide bar 7 Main body 8 Pinion 9 Guide roller 10 Traveling motor 11 Movable shaft 12 Sliding guide bar 13 Sliding guide roller 14 Sliding rope 15 Wheel 16 Drive Motor 17 Guide Sheave 18 Holding Section 19 Fixed Vertical Axis 20 Probe Frame 21 Probe Guide Rail 22 Guide Bar 23 Probe Arm 24 Pulse Reflecting Probe 25 Fixed Axis 26 Fitting Rail 27 Probe Child arm 28 TOF
Probe for D 29 Body cover

Claims (5)

[Claims] 1. A pulse reflection method capable of scanning a probe in a direction along a welding line and a direction perpendicular to the welding line, and a TOFD method capable of scanning a probe in a direction along a welding line. An automatic ultrasonic flaw detection method for welds, which is characterized by combining and performing flaw detection. 2. A TOF method is used for rough flaw detection to obtain TOF.
2. The automatic ultrasonic flaw detection method for a welded portion according to claim 1, wherein the flaw detection is performed by the pulse reflection method by focusing on the welding defect portion detected by the D method. 3. A rail is laid along a welding line, and a main body which is guided by the rail and can run parallel to the welding line is provided. The main body is slidable in a direction perpendicular to the running direction. A welded portion characterized in that a shaft and a fixed shaft projecting in the same direction are provided, a pulse reflection probe is mounted on the movable shaft, and a TOFD probe is mounted on the fixed shaft. Automatic ultrasonic flaw detector. 4. A movable shaft and a fixed shaft can be provided so as to project to the left and right sides of the main body, and the pulse reflection probe and the TOFD probe are arranged on the left side or the right side in the main body traveling direction. The method according to claim 1, characterized in that
An automatic ultrasonic flaw detector for the welds described. 5. A rail is laid along a welding line, and a main body is provided which is guided by the rail and can run parallel to the welding line. The main body is slidable in a direction perpendicular to the running direction. A shaft, and a pulse reflection probe and a TOF on the movable shaft.
An automatic ultrasonic flaw detector for welds, characterized in that a D probe is attached.