JPH0584864B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic ultrasonic flaw detection device that accurately detects welding defects using ultrasonic waves.

(Prior art and its problems) In a conventional ultrasonic flaw detection device, as shown in the plan view of Fig. 4, a so-called bevel probe (hereinafter simply referred to as a probe) 1 having a certain refraction angle is welded. line 2
However, in this case, the ultrasonic wave 3 will not return to the welding defect F that is inclined with respect to the weld line 2, or in this case, the reflected echo will likely be low. There is a risk of overlooking or underestimating welding defect F.

Incidentally, FIG. 7 shows the relationship between the incident angle of ultrasonic waves and the reflected echo height with respect to a welding defect. According to this, welding defect F in a direction almost perpendicular to the direction of incidence of ultrasonic waves
It can be seen that the echo is the highest in the case of , and the echo drops sharply for defects with angles greater than this.

Therefore, in order to compensate for this drawback, as shown in the plan view of FIG. 5A and the cross-sectional view of FIG. If the amount of movement is extremely small, the effect will be similar to the vertical rectangular scan 4 shown by the dotted line in Figure 4.However, this scan is extremely inefficient industrially. JISZ3060-1983 stipulates that scanning should be performed at 15°), but unless the speed of oscillating scanning is extremely faster than the speed of zigzag scanning, the diagonal line in the enlarged cross-sectional view of the weld in Figure 6 There is an undetectable area as shown by section 6. Furthermore, it is difficult to perform swing scanning at extremely high speeds.

Therefore, according to conventional ultrasonic flaw detection equipment,
There is a problem that the detection probability and detection accuracy of welding defects are low.

(Means for Solving the Problems) An automatic ultrasonic flaw detection device according to the present invention includes ultrasonic angle probes that are arranged on both sides of a weld line and have various horizontal angles with respect to the weld line. A plurality of individually built-in holders are connected to the connecting members as a set on each side, and the connecting members on both sides are configured to be movable in the vertical direction at the same time while keeping the relative distance constant, and each connecting member can be moved in the horizontal direction. The probe is held in a movable holding frame, and the connecting member is automatically moved vertically and the holding frame is moved horizontally over the surface of the object to be inspected to simultaneously scan the probes on both sides. .

(Function) In the ultrasonic flaw detection device according to the present invention, probes having various horizontal angles with respect to the weld line are arranged on both sides of the weld line so that simultaneous scanning can be performed. It is possible to accurately detect defects having Defects can be detected and displayed almost as they actually are, eliminating the risk of underestimating defects.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

As shown in the conceptual diagram (A plan view, B cross-sectional view) in FIG. In this case, three probes 1a to 1f are arranged on each side of the weld line. These probes are bevel probes with a constant refraction angle θ, and are connected as a pair on one side by a connecting member 31, and this connecting member 31 is attached to one holding frame 29 perpendicularly to the welding line 2. The holding frame 29 is held movably in a direction (hereinafter referred to as the vertical direction), and is configured to be movable in a direction parallel to the welding line 2 (hereinafter referred to as the lateral direction). That is, by automatically moving the connecting member 31 in the vertical direction and moving the holding frame 29 in the horizontal direction, these probes placed on both sides of the welding line 2 are moved simultaneously and relative to each other as shown in FIG. 3, which will be described later. It is designed to be able to scan vertically while maintaining a constant distance.

The probe 1a on the left side of the welding line 2 is at an angle of α1 clockwise with respect to the perpendicular to the welding line 2, and the probe 1b is at a right angle to the welding line 2 (in this example, it is at a right angle, but it does not necessarily have to be at a right angle. (may be set at any angle), 1c is arranged counterclockwise at an angle α2.

On the other hand, similarly, the probe 1d on the right side is arranged at an angle of β1, the probe 1e is at a right angle, and the probe 1f is arranged at an angle of β2.
The number of probes is not limited to three on each side; for example, n probes having angles of α1 to αn and β1 to βn may be arranged. As the number increases, the defect detection probability and accuracy improve accordingly.

It should be noted that the image display of such flaw detection results through computer processing is the same as in the past, and therefore will not be described here.

As shown in Figure 1, when multiple probes 1a to 1f are placed on both sides of the welding line 2 and scanning is performed simultaneously, each probe is placed at a different angle to the welding line 2. Because of this, it is possible to detect defects with various inclinations, and if the flaw detection results can be displayed for each channel corresponding to each probe, it is possible to detect the probe in the channel with the maximum echo height. Since it is possible to know the inclination of the welding defect from the arrangement angle of the probe.

Furthermore, if the probes on both sides are simultaneously scanned and the flaw detection results of each channel on both sides can be displayed in a composite manner as in the present invention, there is no risk of underestimating defects. In other words, if you scan each side of the weld line and display the detection results, for example, when the actual defect is 20 mm, it may be displayed separately as a 5 mm defect and a 15 mm defect. As shown in 3, by simultaneously scanning the probes on both sides while keeping the relative distance constant, and displaying the results in a composite manner, it is possible to detect an almost actual 20 mm defect. In this case, a 20 mm defect is much more dangerous, so it is significant to scan both probes simultaneously.

Next, the structure of the probe section used to carry out the present invention will be described in detail.

In FIG. 2, A shows a front view of the entire structure of the probe section, B shows a plan view, C shows a right side view, D shows a sectional view taken along line X to B, and E shows a bottom view.

In FIGS. 2A to 2E, a probe 1 having an inverted U-shaped cross section and containing a transducer 9 having a fixed refraction angle is housed in a cylindrical recess C of a holder 7. On one side below this holder 7, a cable terminal 18 provided corresponding to the vibrator 9 is connected at a horizontal angle of ±15°.
An elliptical hole 19 is provided and communicates with the recess C so that it will not come into contact even if touched. By attaching the cable terminal 18 of the probe 1 diagonally upward and enlarging the elliptical hole 19 of the holder 7, the horizontal angle can be increased not only to ±15°.

An angle setting shaft 8 is fixed to the upper part of the probe 1 by passing through the upper part of the holder 7, and a gear-shaped rotation piece 13 having this shaft as an axis is provided on the upper surface of the holder 7. This rotating piece 13 is connected to the holder 7
The screw shaft 1 engages with a screw shaft 11 rotatably mounted between rectangular vertical walls 10 arranged on both sides of the upper surface.
It is designed to rotate by rotation of 1. This rotation is transmitted to the angle setting shaft 8 and causes the probe 1 to rotate. This operation allows the angle of the probe 1 to be set. If the angle setting screw shaft 11
If it is located above instead of on the side like in this structure, it will interfere with the gimbal mechanism attached to the top.

Note that the angle indicator plate 14a conforms to JISZ3060-1983.
Numbers in the range of ±10° to 15° are displayed for the swing angle of the swing scan specified by . And rotating piece 13
An indicator needle 14 fixed to the top of the probe 1 by a clasp 15 hangs down to an angle indicator plate 14a, so that the set angle of the probe 1 can be determined. A groove 11a carved in the head of the screw shaft 11 is formed in the probe 1.
When setting the setting angle of the screw to the specified horizontal angle, insert the tip of a screwdriver etc. into this groove and
It is for rotating.

Recesses are provided at the four corners of the lower end of the holder 7, and a rolling wheel 16 is disposed therein, which is fixed by a shaft 17 so as to be able to move smoothly on the surface of the object to be inspected 5. Note that a shaft hole 20a is provided in the side wall of the holder 7 for pivotally mounting a first gimbal 20, which will be described later.

Next, an automatic scanning device for simultaneously scanning a plurality of probes 1 will be explained with reference to FIG.

FIG. 3A shows a plan view of a case where a plurality of probes 1 are arranged at a predetermined angle on both sides of the weld line 2, and FIG. 3B is a front view thereof.

In FIGS. 3A and 3B, a first gimbal 20 with a rectangular frame is fitted loosely into the holder 7 and pivoted to the shaft hole 20a so as to be able to swing laterally; An inverted U-shaped second gimbal 21 connects to the first gimbal with a shaft 21a near its lower end.
It is pivotally mounted to be able to swing vertically.

The first gimbal 20 and the second gimbal 21
Since both are configured to be swingable, the holder 7 can move smoothly even if the surface of the object to be inspected 5 is warped.

Two vertical rods 22 are planted on the top surface of the second gimbal, and a connecting member 31a is disposed so as to span horizontally between the vertical members 29a of the holding frame 29 formed in the shape of a square frame.
The holders 7 are loosely inserted into the holders 7 to 31b, and connect the holders 7 arranged on the same side. The above two vertical rods 22 are
Its upper end is fixed to a horizontal plate 24 with a stopper 25, so that they are connected to each other via the horizontal plate 24.

Note that the top surface of the second gimbal 21 and the connecting member 31
A spring 23 is loosely fitted into the vertical rod 22 between a and 31b, and presses the spring 23 downward against the up and down movement of the holder 7 due to the unevenness of the 5 surface of the object to be inspected, so that it always remains on the 5 surface of the object to be inspected. It acts like a contact. On the other hand, running wheels 37 are provided on both side legs of the cross member 29b of the holding frame 29 to facilitate smooth movement in the lateral direction. Further, a standing member 29c is erected near the center of one side of the horizontal member 29b, and the stepping motor 3 is connected to this standing member 29c.
3 is attached. And pulleys 34, 3 for transmitting the rotation of the motor to the back side of the upright member 29c.
5 is provided, and a belt 36 is stretched between them.

The rotation shaft 26 coaxial with the pulley 35 is the connecting member 3
It is threadedly inserted into the central boss portion 32 of 1a, and then the connecting member 31b is loosely inserted, and is constructed between the cross members 29b.

Note that the fixed shaft 27, which is symmetrically arranged parallel to the rotation shaft 26 at a constant interval, connects the connecting members 31a,
The connecting members 31a and 31b are loosely inserted into the connecting member 31b and are mounted between the horizontal members 29b, and the connecting members 31a and 31b are regulated by the fixed shaft 27 to move in the vertical direction.

Further, between the connecting members 31a and 31b, a distance adjusting plate 30 is fixed to the connecting member 31a at one end with a stopper 30a, and a distance adjusting plate 30 for setting the vertical distance of the probe 1 is attached to the rotating shaft 26. and the fixed shaft 25. Further, an adjustment fitting 30b is loosely inserted into the long hole H of this interval adjustment plate 30, and is screwed onto the connecting member 31b.

Next, to briefly explain the operation of the above device, the rotation of the stepping motor 33 is controlled by the pulley 3.
4, 35 and the belt 36 to rotate the rotating shaft 26, and the connecting member 31a screwed thereto is driven in the vertical direction, and in conjunction with this, the interval adjusting plate 30
The connecting member 31b connected via the connecting member 31b also moves vertically while keeping the relative distance between the connecting members 31a and 31b constant, and when it moves a certain distance and stops, the holding frame 29 moves to another driving means (not shown). The vehicle then moves sideways for a short distance and then stops. Then, the stepping motor rotates in the opposite direction and the rotating shaft 26 also rotates in the opposite direction, so that the connecting members 31a and 31b simultaneously move in the opposite vertical direction to that described above without changing the relative distance. Then, repeat the above operation again. As a result, vertical rectangular scanning of the probe 1 is automatically performed.

The above series of operations is controlled by a separately provided controller (not shown).

In addition, although the above embodiment shows the case of flaw detection of a butt weld, the present invention is not limited to this, and the present invention is not limited to this. It can also be applied to flaw detection (more scanning).

(Effects of the Invention) According to the automatic ultrasonic flaw detection device according to the present invention, a plurality of probes having various horizontal angles with respect to the weld line are arranged on both sides of the weld line to perform simultaneous scanning. Therefore, the probability of detecting welding defects having various angles with respect to the incident angle of the ultrasonic wave can be significantly increased, and the probes on both sides can be scanned simultaneously while keeping the relative distance constant as in the present invention. In such cases, if the flaw detection results of each channel on both sides can be displayed in a composite manner, it is possible to detect defects almost as they actually are with high accuracy, and there is no risk of underestimating defects.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the present invention, FIG. 2 is a structure of an angle probe used in the present invention, and FIG.
The figure shows an automatic scanning device for implementing the invention. 4 to 6 show the prior art. FIG. 7 shows the relationship between the incident angle of ultrasonic waves and the height of reflected echoes with respect to welding defects. 1... (beveled angle) probe, 2... welding line, 3...
Ultrasonic wave, 5... object to be inspected, 7... holder, 8...
... Angle setting axis, 11 ... Screw shaft, 13 ... Rotating piece, 20 ... First gimbal, 21 ... Second gimbal, 22 ... Vertical rod, 26 ... Rotating axis, 27 ... Fixed axis , 29... Holding frame, 30... Spacing adjustment plate, 3
1, 31a, 31b...Connection material, 33...Stepping motor.

Claims (1)

[Claims] 1. A plurality of holders arranged on both sides of the welding line and each containing ultrasonic angle probes having various horizontal angles with respect to the welding line are connected to the connecting member as a set on each side. The connecting members on both sides are configured to be movable in the vertical direction at the same time while maintaining a constant relative distance, and each connecting member is held in a holding frame that is movable in the horizontal direction, and the connecting members are held in the vertical direction and in the holding frame. An automatic ultrasonic flaw detection apparatus characterized in that the probes are automatically moved laterally over the surface of the object to be inspected to perform simultaneous scanning of the probes on both sides.