JPS6241343B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a rotating probe type ultrasonic flaw detector.
The present invention relates to a rotary probe holder that can rotate to follow a material to be inspected even if the axial center position of the material to be inspected is changed in the axial direction.

In order to perform ultrasonic flaw detection on long rolled products with circular cross-sections, such as pipes and round bars, the probe is rotated at high speed along the outer circumference of the material to be inspected, and the material to be inspected is moved straight in the axial direction. A so-called rotating probe type flaw detector is often used, which scans the outer circumference of the material to be inspected with a spiral probe to detect flaws over the entire length of the surface. This type of ultrasonic flaw detection equipment rotates a rotary probe holder equipped with multi-channel probes at high speed, so the flaw detection speed is fast and inspection can be performed with extremely high efficiency, making it suitable for use in steel pipe manufacturing factories, steel bar manufacturing factories, etc. It is used as an important non-destructive testing device.

Although this flaw detection device is suitable for highly efficient flaw detection, on the other hand, if the straightness of the inspected material is poor, problems such as those described below may occur, making flaw detection unstable or even impossible. Conventionally, there was a drawback in that strict limits were set on the straightness of the material to be inspected, and it had to be used within the limits.

In order to eliminate such drawbacks, the present invention makes the rotary probe holder attached to the rotor of a flaw detector a double cylinder consisting of an outer cylinder and an inner cylinder containing the probe. The inner cylinder is held in a floating state by a bellows attached to both end faces thereof or by an elastic body such as a spring provided between the bellows and the outer wall of the inner cylinder and the inner wall of the outer cylinder. Spiral flaw detection can be performed by following the eccentricity of the transferred material to be inspected and by rotating the inner cylinder at high speed along the outer periphery of the material to be inspected while holding it in an ideal relative position.
It is an object of the present invention to provide a probe holder for a rotating probe type ultrasonic flaw detector that can detect flaws at high speed and with high efficiency even on a highly curved inspected material.

Figure 1 is a schematic diagram showing the overall appearance of a rotating probe type ultrasonic flaw detector.
is mounted on a lifting frame 2, 3 is a two-tiered pinch roll stand on the input side of the inspected material, and 4 is a two-tiered pinch roll stand on the outlet side, and these are assembled on a common base 5. . A material to be inspected 6 passes through the main body 1 and is conveyed in the direction of the arrow in the figure while its movement is restricted by the pinch roll stands 3 and 4 on the entry and exit sides. Although not shown in FIG. 1, a rotary probe holder built into the main body 1 rotates around the outer circumference of the material to be inspected 6 at high speed to perform flaw detection in a spiral manner.

FIG. 2 is an explanatory axial cross-sectional view of a conventional rotary probe holder, in which the inspected material 6 is mounted on a bearing 15 in the main body 1.
A rotor 12 supported by a and 15b and a rotating probe holder 1 attached to an end surface 13 of the rotor
4 and is conveyed in the direction of the arrow. Further, the rotor 12 is connected to an external drive source and rotationally driven by a timing belt 17 and a timing pulley 16 meshing with the timing belt 17. Note that the cylindrical portion of the rotor 12 is generally provided with slip rings and other elements for signal transmission. Furthermore, even if the fixed guide 18 deeply inserted into the hole inside the rotor 12 swings due to the bending of the inspected material 6 entering the rotor 12, it is covered by the tapered guides 18a and 18b provided on the entry side and the exit side. It works to forcibly guide the inspection material 6 and stably introduce it into the inner hole of the rotary probe holder 14.

On the other hand, the rotating probe holder 14 has a required number of probes 20, a spout 19, and a water channel 21, and water as a couplant is supplied through a tapered surface 22 from a fixed supply element 23 that is always pressed against the tapered surface. The space 24 between the outer surface of the object 6 to be inspected and the inner surface of the rotary probe holder is always filled with water as a couplant.

FIG. 3 is a diagram illustrating the relationship between the positions and functions of the rotating probe 14 and the material to be inspected 6, where A indicates the distance when the rotating probe holder 14 and the material to be inspected 6 are concentric, and B indicates the distance. This shows the case where it is eccentric by d. In the concentric case, the void 24 is uniform along the entire circumference, the couplant water is sheared uniformly, and the flow state is stable, but
In the case of eccentricity, the air gap 24 is not uniform, and the flow of water in the circumferential direction due to high-speed rotation of the rotating probe holder 14 becomes unstable, and in particular, water flows into the inner wall surface of the rotating probe holder due to centrifugal force. If the amount of eccentricity is large, air bubbles will be drawn into the area with the largest gap, making flaw detection impossible. On the other hand, for example, in the case of angle inspection of steel pipes, the ultrasonic beam emitted from the probe 20 attached to the rotating probe holder 14 enters the surface of the material 6 to be inspected through the water column 25 as shown in the figure. However, when the rotating probe holder 14 and the material to be inspected 6 are concentric, the refraction angle is uniform regardless of the rotational position, and ideal flaw detection can be performed. On the other hand, in the case of eccentricity, the rotating probe holder 14 rotates, so the refraction angle varies depending on the rotational position.

In this case, according to a flaw detection experiment using a groove-shaped artificial defect provided in the axial direction of the inspected material, when the amount of eccentricity was 1.5% of the outer diameter of the inspected material, a defect echo height fluctuation of approximately 3 dB was observed. Since it is necessary to suppress the echo height variation for the same defect to about 3 dB, it can be seen that the allowable limit for eccentricity should be about 1.5% of the outer diameter of the material to be inspected.

Such a rotating probe holder 14 and the material to be inspected 6
Due to the allowable eccentricity limit of Means for ensuring retention are arranged, and a common base 5 is provided as shown in FIG.
Assemble the pinch roll and main body 1 on top to improve vertical and horizontal centering accuracy, or if the inspected material 6 has a small diameter and thin wall and can be elastically bent by external force, insert the fixed guide 18 shown in Fig. 2. Side and exit side guide 18
A means for increasing the concentricity of the rotary probe holder 14 and the material to be inspected 6 is implemented by narrowing the inner diameters of A and 18B, that is, by making the gap with the material to be inspected 6 as small as possible.

In addition, if the material to be inspected 6 has a large diameter and thick wall and cannot be bent by external force, the main body 1 is supported floatingly on the elevating frame 2 with springs or the like as shown in FIG. There is an idea that the main body 1 is made to follow the tapered guides 18a and 18b of the fixed guide 18 in Fig. 2, but the mass of the main body 1 is large and the rotational inertia of the rotor 12 is also large. A large perturbation couple occurs when angular deviation occurs, making it difficult to implement in practice.

In view of the above points, conventionally, it has been common practice to inspect bent materials 6 for defects upstream of transportation so that only those that are as straight as possible are inspected for flaws, and to remove the bent materials. However, steel pipes have relatively little bending due to the manufacturing process, but round steel bars generally have more bends than steel pipes, but even if they are straightened, the cost will only increase and the value will not be recognized in terms of quality. Therefore, no correction is performed, and in this sense, there are currently fewer examples of application of rotating probe type flaw detectors to round steel bars than to steel pipes.

The present invention makes it possible to detect even thick curved materials with large diameters by rotating only the rotary probe holder, which has a small mass, and making it follow the material to be inspected when the position of the material to be inspected changes. . The gist of the present invention will be explained in detail below with reference to the figures.

FIG. 4 is an axial cross-sectional explanatory diagram of an embodiment of a probe holder for a rotating probe type ultrasonic flaw detector of the present invention, FIG. 5 is a sectional view of FIG. 4, and the probe is shown in FIG. , a mounting spacer, and an exploded perspective view of the mounting hole portion will be explained. In the explanation, the parts having the same reference numerals as those explained before FIG. 3 have the same names and the same parts, so the explanation will be omitted.

The rotating probe holder attached to the end face 13 of the rotor 12 has a double cylindrical structure. That is, there is an inner cylinder 32 inside the outer cylinder 31, and the outer cylinder 31 is attached to the end surface 13 of the rotor. The inner cylinder 32 is supported in a floating state within the outer cylinder 31 by a large number of coil springs 33 installed in the radial direction in the gap between the inner cylinder 32 and bellows 34 and 35 on the inlet and outlet sides of the inner cylinder 32, respectively. is connected to the outer cylinder 31. Since the bellows 34 and 35 are flexible, the inner cylinder 32 can be eccentric with respect to the outer cylinder 31 and transmit the rotation of the outer cylinder 31 to the inner cylinder 32. In order to prevent the bellows from being excessively displaced in the axial direction due to contact between the inspected material 6 and the inner surface of the inner tube 32, the inner tube 32 is pulled toward the exit side and the bellows is not displaced excessively in the axial direction. At least one of the protrusions 37 is provided on the outer surface of the cylindrical member 32 over the entire circumference, thereby bringing the protrusions into contact with each other to form a stopper for axial displacement. On the entry side of the inner cylinder 32, a lapper guide 32a having a conical surface is provided to guide the tip of the inspected material 6 when it enters.

The inner diameter of the inner cylinder 32 is 3% larger than the outer diameter of the material to be inspected 6.
The dimensions are relatively large, so that the eccentricity of the inspected material 6 with respect to the inner cylinder 32 is within 1.5% of the outer diameter of the inspected material, and the dimensions are such that there is no problem in passing the inspected material 6 through the inner tube 32. .

Also, as explained in FIG. 2, there is a means for supplying couplant water to the outer cylinder 31 of the rotary probe holder, and the water supplied to the outer cylinder 31 is distributed between the inner wall of the outer cylinder 31 and the outer wall of the inner cylinder 32. It is guided into a waterway space 21' created by bellows 34,35. That is, the fifth
As shown in the figure and FIG. 6, the water introduced into this space is formed between the protrusion 39a of the mounting spacer 39 and the mounting hole 41 for mounting the required number of probes 20 mounted on the inner cylinder 32. The water is ejected through the sector-shaped space 40 into the gap 24 between the inner tube 32 and the material to be inspected 6, filling the gap 24 with couplant water. This couplant water allows the ultrasonic beam emitted from the probe 20 to be incident on the inspected material 6, and the reflected echo can be received by the probe.

Note that in the above description of the present invention, the outer cylinder 31 and the inner cylinder 3 are
In addition to the bellows 34 and 35, a coil spring 33 was provided between the bellows 34 and 2, but since the bellows is flexible and has a rotation transmission function and a center return function, the coil spring 33 is not necessary. Depending on the conditions, a design that achieves the object of the present invention is possible. However, since the above-mentioned center return function is generally weak, it is easier to design and operate more reliably if the coil spring 33 is provided with a center return function.

As described above, according to the present invention, even if the inspected material 6 is eccentric, the inner cylinder 32 to which the probe 20 is mounted follows the eccentricity of the inspected material 6, and the inner cylinder 32 is moved along the outer circumference of the inspected material 6. can be rotated at high speed, and rotational flaw detection can be performed while holding the probe 20 at an ideal relative position to the material 6 to be inspected. Therefore, even if the material to be inspected is thick with a large diameter and has a large bend, it is almost unrestricted by the bend and can be used for a versatile rotating probe type ultrasonic flaw detector that can detect flaws at high speed and high efficiency. A feeler holder can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the overall appearance of a rotating probe type ultrasonic flaw detector. FIG. 2 is an explanatory axial cross-sectional view of a conventional rotating probe holder section. Figure 3 is an explanatory diagram of the relationship between the position and function of the rotating probe and the material to be inspected. In A, the rotating probe and the material to be inspected are concentric, and in B, the center distance is d.
This is the case when the position is eccentric. FIG. 4 is an explanatory axial cross-sectional view of an embodiment of a probe holder for a probe rotating type ultrasonic flaw detector according to the present invention, and FIG.
The sectional view and FIG. 6 are exploded perspective views of the probe, mounting spacer, and mounting hole. DESCRIPTION OF SYMBOLS 1... Main body, 6... Material to be inspected, 12... Rotor, 14... Rotating probe holder, 17... Timing belt, 18, 38... Fixed guide, 19...
...Ejection port, 20...Probe, 22...Tapered surface,
23...Fixed supply element, 24...Gap, 31...Outer cylinder, 32...Inner cylinder, 33...Coil spring, 34,
35... bellows, 36, 37... change, 39...
...Mounting spacer.

Claims (1)

[Scope of Claims] 1. In a rotating probe holder attached to a rotating probe type flaw detector, the structure of the holder is a double layer consisting of an outer cylinder and an inner cylinder that are attached to the rotor of the flaw detector and rotate. The inner cylinder is connected to the outer cylinder by a bellows that surrounds the material to be inspected at the entrance and exit sides of the material to be inspected being conveyed in the axial direction, and the inner cylinder is connected to the outer cylinder. water is supplied and filled into the gap formed by the inner wall of the outer cylinder, the outer wall of the inner cylinder, and the bellows, and is further jetted from a passage passing through the inner surface of the inner cylinder. Possibly, a gap between the inner surface of the inner tube and the material to be inspected is filled with water, and a gap between the probe attached to the inner tube facing the inner surface of the inner tube and the material to be inspected is filled. A probe holder for a probe rotating type ultrasonic flaw detector, which is capable of transmitting and receiving ultrasonic waves. 2. In a rotary probe holder attached to a probe rotating type flaw detector, the structure of the holder is a double cylinder consisting of an outer cylinder and an inner cylinder that are attached to the rotor of the flaw detector and rotate, and the outer cylinder The inner tube is connected to the outer tube by a bellows that surrounds the inspected material at the entrance and exit sides of the inspected material being conveyed in the axial direction, and the inner tube is connected to the outer tube by a spring or the like. water is maintained in a floating state by an elastic body, and water is supplied to fill the gap formed by the inner wall of the outer cylinder, the outer wall of the inner cylinder, and the bellows, and is further jetted from a passage passing through the inner surface of the inner cylinder. The space between the inner surface of the inner cylinder and the material to be inspected is filled with water by A probe holder for a probe rotating type ultrasonic flaw detector, which is capable of transmitting and receiving ultrasonic waves.