JPS59782B2 - On-pattern training - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an automatic ultrasonic flaw detector mainly used for flaw detection of circumferential welded joints of steel pipes.

As is well known, for circumferentially welded joints of steel pipes, a probe is brought into direct contact with the surface of the steel pipe across the weld, and moved circumferentially while maintaining a fixed distance from the weld, to detect the inside of the weld. The defect echo reflected from the defect is determined.

Therefore, in this type of ultrasonic flaw detection, it is important to always maintain the position of each probe at a constant distance from the weld bead. The conventional method is to first mark a reference line on the pipe to be inspected at a certain distance from the circumferential weld, apply couplant, and then have one of the inspectors move the probe along the reference line. A method is adopted in which the defect position within the weld is estimated from the height of the echo and the rising position of the echo on the time axis (horizontal axis) by carefully observing the determination device (cathode ray tube) that displays the echo while moving. It is being However, with this manual flaw detection, the inspector's posture becomes unstable as the probe moves, making it difficult to maintain the correct position of the probe, and the contact pressure of the probe tends to change. It is necessary to change the direction of the judgment (CRT) device one by one so that the inspector can clearly confirm the change in the echo height and the position of the rise of the echo, and the inspector must change the direction of the judgment (CRT) device in advance. The automatic method is particularly effective in detecting flaws in circumferential welded joints. The purpose is to provide an ultrasonic flaw detector. A feature of this invention is that in the case of circumferentially welded joints of steel pipes, the main body of the flaw detector can detect flaws while automatically moving in the circumferential direction over the pipe to be inspected. Inspection preparation work can be omitted, flaw detection work and echo discrimination work can be performed remotely, records can be easily recorded, and flaw detection accuracy can be improved and inspection time can be significantly shortened.

The specific structure of the present invention will be explained below with reference to the drawings of one embodiment. Fig. 1 is a partially cutaway plan view of the device of the present invention, Fig. 2 is a cutaway side view of the same essential parts, Fig. 3 is a longitudinal sectional front view taken on the line l of Fig. 2, and Fig. 4 is taken on the line of Fig. 1. Longitudinal front view of, No. 5
The figure is a longitudinal sectional front view taken along the line of FIG. 1.

FIG. 6 shows an example of the use of the apparatus of the present invention for flaw detection of a circumferential weld of a tube T to be inspected.

In this example, the flaw detector and the like mounted on the trolley 1 are attached to the tube T to be inspected by a spring arm 35 and rotate freely in the circumferential direction along the weld bead. In FIGS. 1 and 2, a bogie 1 has a convex central portion 2, and running wheels 3 are provided at the four corners. This wheel is preferably a magnetic wheel to ensure contact with the tube T to be inspected. A drive motor 4 is mounted on the upper surface of the trolley 1, one of rotation transmission shafts 5 disposed at both ends of the frame is connected to the drive motor shaft via reduction gears 61 to 64, and one of the rotation transmission shafts 5 attached to both ends of the transmission shaft is connected to the drive motor shaft through reduction gears 61 to 64. A chain belt 9 is connected between the sprockets S1 to R4, and the opposing sprockets S', , S are connected to the other sprockets S2 to S6 and attached to the shaft of the wheel 3.
'3, S'5, and S'6 are connected by a chain belt 10, and four traveling wheels 3 are driven simultaneously. The probe device, which is the main body of the flaw detection device, is equipped with two rollers 13 on both side plates 12, one on top and one on top, so that it can slide smoothly in the direction perpendicular to the weld bead 16, sandwiching rails 27 provided on the main frame 26. on the frame 11 each provided at a fixed position,
Four transmitting and receiving probes 151, 153, 152, 154 are attached to the weld bead 16 in a space created by a plurality of partition plates 14.
Built-in probe box 171 that can freely slide in the direction perpendicular to the
174 is inserted vertically movably, the guide bolt 18 protruding from the top surface of the box is loosely passed through the nut 19 attached to the frame 11 with a buffer spring 20 interposed, and the upper part is fixed with the nut 21. The probe boxes 171 to 174 are fixed. As shown in FIG. 4, the flaw probes 151 to 154 built into each probe box are connected to a support bolt 22 installed at one end of the flaw probes 151 to 154.
The nut 2 is inserted through the side of the box through the buffer spring 23, and the upper part of the bolt is inserted into the notch 24 provided in the bulkhead plate.
5, and the other end faces the window hole 24' provided in the opposing partition plate 14, and the lower part thereof is fixed with a bolt 22'.

As shown in FIGS. 1 and 4, the probe box frame 11
The two upper and lower rollers 13 provided on both side plates 12 form a weld bead 16 on the rails 27 provided on the left and right inner walls of the main frame 26.
It is mounted so that it can be suspended and run horizontally and at right angles to the main frame, and is fitted into the recess 28 of the trolley 1, and the support shaft 29 protruding from the upper surface of the main frame is loosely passed through the trolley 1, with a plurality of washers interposed. Then, secure the upper part of the bolt with nut 30. That is, the main frame 26 can swing freely in the horizontal direction about the support shaft 29 and can also move horizontally in a direction perpendicular to the weld bead, and the right and left limits of its movement are provided at the ends of the rails 27. It is assumed that the stopper is up to 31. Needless to say, the reason why the device is made movable is to maintain a constant distance between the weld bead and the probe even when the weld bead bends or meandering when the truck travels. As shown in FIGS. 1, 2, and 5, a pair of distance-maintaining magnets 32 are attached to the frame 11 of the probe box in order to maintain a constant distance between the probe and the bead. .

This spacing maintaining magnet is made by integrally holding a magnet 32 between two steel plates 33, and two spacer shafts 34 are installed horizontally at both ends of each of the front and rear, and one of the spacer shafts 34 is probed. It loosely penetrates both side plates 12 of the slave box fixing frame and is freely rotatable in the vertical direction. In the figure, numeral 39 is a handle to be grasped when moving or transporting the device. FIG. 6 shows the state of use when applied to flaw detection of circumferential welded joints of steel pipes. In this case, a spring arm 35 is used so that the main body of the apparatus can run in contact with the pipe to be inspected at a constant pressure.

This spring arm has a detachable lever device 36 for the arm main body at one end, the front end of which can be attached to and detached from the cart 1 of the flaw detection device, and a rubber roller 37 attached to the other end for smooth rotation. , the arm body opens outward by firmly grasping the two main levers 38. When the above-mentioned ultrasonic flaw detection device is placed on the pipe to be inspected across the weld bead 16, and the front and rear pairs of magnets are brought into contact with both sides of the weld bead, the distance between the weld bead and the probe is set accurately. Start the drive motor 4.

At the same time as the motor is driven, the flaw detector moves circumferentially along the weld bead and performs continuous flaw detection. In this ultrasonic flaw detection, as described above, it is most important for inspection accuracy to always maintain a constant distance between the weld bead and the probe. FIG. 5 shows a cross-sectional view taken along the - line in FIG. The distance between the probe and the probe can be kept constant at all times.

Furthermore, since the probe has a buffer mechanism, it can always slide smoothly under a constant pressure even if the surface of the tube to be inspected is uneven. As described above, in the case of circumferentially welded joints of steel pipes, the present invention allows the flaw detector to detect flaws while automatically moving over the pipe to be inspected, eliminating the need for work such as marking reference lines. In addition to saving labor, flaw detector control and judgment work can be done remotely, and records can be easily recorded.

In addition, maintaining the distance between the probe and the weld bead, which is the most important factor in ultrasonic flaw detection, is extremely stable due to the action of the magnet, which has the effect of improving flaw detection accuracy. Furthermore, while conventional manual flaw detection required approximately 2 hours for inspection, the present invention significantly shortened the time to 30 minutes.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway plan view of the present invention, Fig. 2 is a cutaway side view of the same essential parts, Fig. 3 is a longitudinal sectional front view taken along the line I-I in Fig. 2,
Figure 4 is a longitudinal sectional front view on the line of Figure 1, and Figure 5 is Figure 1.
FIG. 6 is a side view showing this embodiment.

Claims (1)

[Claims] 1. A truck equipped with wheels and a drive device for the wheels that run along the weld bead of the pipe to be inspected, a frame mounted on the truck and movable in a direction perpendicular to the traveling direction of the truck, and a frame attached to the lower part of the frame. At the front and back of the above-mentioned frame are four probes that also transmit and receive signals, and a pair of magnets that abut on both sides of the weld bead to maintain a constant distance between the probes and the weld bead of the tube to be inspected. An automatic ultrasonic flaw detector for circumferential welds of metal pipes, comprising one set of each set and a carriage mounting mechanism for mounting the carriages so that the carriages can smoothly run around the pipe to be inspected.