JPS6310783B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for detecting minute defects at the bottom of a penetration weld.

Conventionally, when it comes to partial penetration welding, emphasis is placed primarily on shear strength, and as long as the throat thickness is secured, the shape of the penetration line at the bottom (root) and the presence or absence of minute defects in that area can be completely ignored. Since they were not seen as a problem, there was no established method for properly detecting them. However, recently, fatigue test results for steel structures such as bridges have shown that cracks occur at locations where the penetration line at the bottom of corner joint welds has changed significantly, or at micro-defects in these locations, reducing fatigue strength. In addition to the conventional quality, two items have been added: smooth bottom shape and no micro defects.

The difficulty in detecting micro defects at the bottom of the penetration zone using ultrasonic flaw detection technology is that the micro defects must be detected at the weld metal part, which is always 1 to 2 mm from the penetration line, which does not fluctuate. The point is that the beam for the purpose must be incident.

The present invention provides a sensor for detecting a penetration line in addition to a probe for detecting minute defects, and causes the probe holder to move in accordance with the penetration line. By mounting at specified intervals based on the installation position of the welding line, no matter how the welding line changes, the beam for micro defect detection will always be incident on the inspection point within 1 to 2 mm from the welding line. The details of the present invention will be described below with reference to the embodiments shown in the drawings.

In the figure, reference numeral 1 denotes a traveling frame connected to a traveling trolley 4 that travels at a constant speed on guide rails 2 by means of a trolley traveling controller 3, and is capable of moving straight on the surface of one of the materials along the penetration welding location. As shown in FIGS. 3 and 4, two guide rods 7, 7 are passed to a square frame member 6 having three wheels 5, and the probe holder 8 is slid in the left and right directions. A protruding rack 9 that is movable and has one end fixed to the probe holder 8 is engaged with a pinion 11 fixed to the output shaft of a servo motor 10 attached to the frame member 6.

A vertical ultrasonic probe 12, which is a sensor for detecting the penetration line, is attached to the probe holder 8. The ultrasonic waves incident with this vertical ultrasonic probe 12 are transmitted through the welded part in the change detection range, and are reflected outside of the welded part, and the reflected echoes are transmitted through the probe 12.
and changes its output voltage. In other words, a change in the output voltage of the probe 12 corresponds to a change in the ultrasonic reflectance. The drive circuit of the servo motor 10 includes a balance controller 14 to which the output voltage of the probe 12 is sent via an ultrasonic receiver 13.
has been established. This balance controller 14 detects the difference between the input voltage and the set reference voltage, and issues a signal to the servo motor 10 to rotate clockwise, counterclockwise, or stop so as to make the difference zero. The fact that the difference from the set reference voltage that occurs when the penetration line changes is zero means that the probe holder 8 is moved left and right by the servo motor 10 so that the probe 12 follows the penetration line. be.

In the present invention, the ultrasonic probes 15, 15' for detecting minute defects are attached to the probe holder 8, which moves to follow the penetration line. Generally, in order to detect minute defects of about 0.5 to 1 mmφ, it is necessary to use a focusing type probe that has a high frequency of 5 to 10 MHz and narrows the beam width to obtain high resolution. Beam 15 is probe 1 for detecting the penetration line.
For the reasons mentioned above, the beam spacing is, for example, 1.
Probe 1 so that it can be about 2 mm
5 uses an oblique focusing type. Similarly, the other probes 15' are of the oblique focusing type, and in this case, they are mounted so that the beam distance from the probe 15 is appropriately spaced. As shown, both probes 15, 15'
If they are attached at the front and rear positions with respect to the probe 12, they can be attached without interfering with each other. Both probes 15,
The output signals from 15' are recorded on pen recorder 17 or magnetic recorder 18 through ultrasonic transceivers 16 and 16', respectively. The pen recorder 17 or the magnetic recorder 18 may also record the marker signal from the traveling position detector 19 of the traveling carriage 4 at the same time.

As is clear from the above description, the present invention has a probe that is movable left and right by a servo motor 10 on a traveling frame 1 that can move straight on the surface of one material along a penetration welding location. Holder 8
The servo motor drive circuit is equipped with a vertical ultrasonic probe 1, which is a sensor for detecting the penetration line at the bottom of the penetration welding location, which is attached to the probe holder 8.
A balance controller 14 is provided to send a signal to the servo motor 10 so as to make the difference between the input voltage proportional to the output voltage of the probe 2 and the set reference voltage zero, and the probe holder 8 is provided with a balance controller 14 that outputs a signal to the servo motor 10 so as to make the difference between the input voltage proportional to the output voltage of the probe 2 and the set reference voltage zero. At least one oblique focusing type ultrasonic probe 15 for detecting minute defects at the bottom of the penetration welding part is attached at appropriate intervals and the output change is recorded. No matter how the line changes, micro defects at the bottom of the penetration weld can be detected accurately and reliably.

[Brief explanation of the drawing]

1 and 2 are a plan view and a side view showing the apparatus of the present invention, and FIGS. 3 and 4 are a plan view and a side view of the traveling frame. 1... Traveling frame body, 8... Probe holder, 1
0... Servo motor, 12... Vertical ultrasonic probe, 14... Balance controller, 15... Oblique focusing type probe.

Claims (1)

[Claims] 1 A servo motor 10 is attached to a traveling frame 1 that can move straight on the surface of one of the materials along the penetration welding location.
A probe holder 8 is provided which is movable in the left and right directions, and its servo motor drive circuit includes a vertical ultrasonic detector which is a sensor for detecting the penetration line at the bottom of the penetration welding point attached to the probe holder 8. A balance controller 14 is provided to send a signal to the servo motor 10 so as to make the difference between the input voltage proportional to the output voltage of the probe 12 and the set reference voltage zero, and the probe holder 8 is provided with a balance controller 14 that outputs a signal to the servo motor 10 so as to make the difference between the input voltage proportional to the output voltage of the probe 12 and the set reference voltage zero. An oblique focusing type ultrasonic probe 1 for detecting minute defects at the bottom of the penetration welding part is placed at an appropriate distance from the beam.
A device for detecting minute defects at the bottom of a penetration welding part, which is configured to record changes in output by attaching at least one unit 5.