JPS6326864B2 - - 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 the 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 provides a structure of a rotating probe holder attached to the rotor of a flaw detector by providing an arm that swings around a rotating shaft supported by a holding frame, and an arm that swings around a rotating shaft supported by a holding frame. A rod with a spherical bearing at the tip is attached facing the material to be inspected, and a probe head having a cylindrical surface that covers less than half the circumference of the material to be inspected and with the required number of probes attached is mounted using the spherical bearing. By holding the probe in a floating state and attaching a balance weight to the other end of the arm, the probe head can be made to follow the eccentricity of the inspected material being conveyed in the axial direction, and at high speed along the outer periphery of the inspected material. We provide a probe holder for a rotating probe-type ultrasonic flaw detector that can perform spiral flaw detection by holding the probe in an ideal relative position while rotating, allowing high-speed, high-efficiency flaw detection even on highly curved test materials. This is what I am trying to do.

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 at high speed around the outer circumference of the material to be inspected 6 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 rotary 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 water 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 accompanying the high-speed rotation of the rotating probe holder 14 becomes unstable, especially when water flows inside the rotating probe holder due to centrifugal force. Since it tends to stick to the wall surface, if the amount of eccentricity is large, air bubbles will be drawn into the area of the largest gap, making flaw detection impossible. On the other hand, for example, in the case of oblique flaw detection of steel pipes, the ultrasonic beam emitted from the probe 20 attached to the rotating probe holder 14 as shown in the figure
However, if the rotary 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 is 1.5% of the outer diameter of the inspected material, a 3 dB defect echo height variation was observed, and in normal flaw detection, Since it is necessary to suppress the echo height variation for the same defect to about 3 dB, it is clear 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
As shown in Fig. 1, due to the allowable limit of eccentricity of In addition, as shown in Fig. 1, the pinch roll and main body 1 are assembled on a common base 5 to improve vertical and horizontal centering accuracy. If the fixed guide 18 can be elastically bent by
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 the rotary probe holder 14 and the material to be inspected 6, that is, by making the gap between the rotary probe holder 14 and the material to be inspected 6 as small as possible.

In addition, if the material to be inspected 6 has a large diameter and a thick wall and cannot be bent by external force at all, 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 main body 1 has a large mass and the rotor 12 has a large rotational inertial mass. A large perturbation couple occurs when angular deviation occurs, making it difficult to implement in practice.

In view of the above, conventional measures have been taken to inspect only the specimen 6 that is as straight as possible, such as inspecting bent specimens for bends upstream of the conveyance and pushing them out. 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.

In the present invention, when the position of the inspected material changes, even thick curved materials with large diameters can be detected by rotating only the probe head of the rotating probe holder, which has a small mass, and making it follow the inspected material. This is what I did. The gist of the present invention will be explained in detail below with reference to the figures.

The axial cross-sectional explanatory view of one embodiment of the probe holder for a probe rotating type ultrasonic flaw detector of the present invention shown in FIG. 4 will be explained. In the following explanation, 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.

Two holding frames 32 _-1 and 32 _-2 integrally protrude from the mounting disk 31 of the rotary probe holder attached to the end face 13 of the rotor 12, and the rotating shaft 33 fixed to the holding frames An arm 34 is provided which is pivotally supported so as to be able to swing freely in the direction toward and away from the material to be inspected, and a rod 36 having a spherical bearing 35 at the tip is attached to one end toward the material to be inspected. The probe 20 has a cylindrical surface 37a covering half the circumference or less of
The probe head 37 with the spherical bearing 35 attached thereto is
The probe head 37 is held at the other end of the arm 34 so as to be able to contact the material 6 to be inspected.
A balance weight 39 is attached that is heavy enough to press the inspected material 6 with an appropriate force. It also covers the rod 36 and the arm 34 and probe head 37.
A bellows 40 is installed between the bellows 40 and a water pipe 41 introduced into the arm 34 side of the bellows 40.
Further, the probe head 37 side of the bellows 40 is opened at the upper end of the spherical bearing 35, and water, which is a rotating couplant, flows from a passage 42 into a water column chamber 43 extending from the tip of the probe 20 to the cylindrical surface 37 _-a . guide.

In addition, as shown in FIG. 4, the holding frames 32 _-1 , 32
In addition to the rotating shaft 33, a rotating shaft 33' is fixed to _-2 , and parts similar to those described above are installed symmetrically to the cylindrical surface 37' _-a of the probe head 37' and the cylindrical surface 37'.
_-a sandwich the material 6 to be inspected, but since it would complicate the diagram, the leader lines and symbols have been omitted.

Further, a rotary water supply element 44 having a water channel 44a connected to the water pipe 41 and a tapered surface 44b is attached to the tips of the holding frames 32 _-1 and 32 _-2 , and the rotating water supply element 44 is always connected to the tapered surface 44b through the tapered surface 44b.
Water, which is a couplant, is supplied from a fixed water supply element 45 that is pressed against the fixed water supply element 45 and has a tapered surface and a water supply piping port 45a.

With the structure as described above, when the inspected material 6 comes in the direction of the arrow, the probe head rotating together with the mounting disk 31 runs over and becomes cylindrical due to the action of the shoe 37b, the spherical bearing 35, and the rotating shaft 33. Face 37
a and 37'a follow the cylindrical surface of the material 6 to be inspected and are pressed against it with an appropriate force by the function of the balance weight 39 while relatively spirally sliding. At this time, the center C of the inspected material 6 may be bent due to the bending of the inspected material 6.
It is easy to understand that if the holding frames _{32 -1} and 32 -2 are eccentric in the axial direction, the cylindrical surface 37a follows the cylindrical surface of the inspected material 6 due to the action of the spherical bearing 35 and the rotating shaft ₃₃ . When the probe is eccentric by d in the direction perpendicular to the surface, the probe head 37 is tilted by the action of the spherical bearing 35, the rotary shaft 33, and the deflection of the bellows 40, as shown in FIG. It can be made to follow the cylindrical surface of. In addition, the material to be inspected 6
In response to the tilting of the cylindrical surface of the material to be inspected 6 during the process in which the center C moves eccentrically in various directions with respect to the probe holder due to the bending of the cylindrical surface 37a It is easy to understand that it can be imitated. In reality, the eccentric direction due to bending of the inspected material 6 is often a combination of the individual cases as described above, but the above movements are combined to ensure that the cylindrical surfaces 37a, 37'
a can be made to follow and imitate the cylindrical surface of the inspected material 6.

On the other hand, water is supplied from the piping port 45a, passes through the waterway 44a, the water pipe 41, the inner surface of the bellows 40, and the waterway 42 through the tapered surface 44b, and fills the water column chamber 43 with couplant water, and the cylindrical surface 37a and the material to be inspected 6. Probe 2 comes out from the gap between the outer cylindrical surface and the outer cylindrical surface.
The ultrasonic beam emitted from zero can be incident on the inspected material 6, and the reflected echo can be received by the probe 20.

As described above, according to the present invention, even if the inspected material 6 has a large bend, the probe heads 37, 37' rotate at high speed and reliably align the cylindrical surfaces 37a, 37'a with the outer cylindrical surface of the inspected material 6. Since it can be traced and traced, there is almost no change in the thickness of the couplant water, and therefore stable spiral flaw detection with almost no echo height fluctuation can be performed quickly and efficiently, and it is also possible to It is possible to provide a probe holder for a probe rotating type ultrasonic flaw detector that is versatile and capable of detecting flaws even in thick and curved bars that cannot be corrected with pinch rolls or fixed guides.

In addition, in FIG. 4, before the material to be inspected 6 enters the probe holder, the probe heads 37 and 37' are in contact with each other due to the function of the balance weight and are pressed against each other or are oriented in an unfavorable direction. If the probe head 37,3
Stopper protrusions 37C and 37'C protrude from both sides of the probe head 7', and the probe heads 37 _{and 37 are placed on the inclined surfaces 32-1aa and 32-2a} at the tips of the holding frames 32-1 and _32-2 . ′ is kept ideal. In addition, the probe head 37 and the stopper protrusions 37C and 37'C are properly guided and placed on the inclined surfaces _32-1a and _32-2a when the inspected material 6 is completely removed from the probe holder.
37' is provided with guide slopes 37d and 37'd.

In the embodiment of the present invention shown in FIGS. 4 and 5, there are two probe heads 37, 37' supported in a floating state on two rotating shafts 33, 33', respectively. The number of probe heads is not necessarily limited to two, and may be one or three or more, in accordance with the technical idea of the present invention.

[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 rotary probe holder section. Figure 3 is an explanatory diagram of the relationship between the position and function of the rotating probe and the inspected material.
This is the case when the position is eccentric. FIG. 4 is an explanatory axial cross-sectional view of an embodiment of the probe holder for a probe rotating type ultrasonic flaw detector of the present invention, and FIG. 5 is a partially cutaway view of the probe holder shown in FIG. 4. The perspective view and FIG. 6 are explanatory diagrams showing the following state of the probe head when the center of the inspected material moves. 1... Main body, 6... Material to be inspected, 12... Rotor, 14
...Rotating probe holder, 17...Timing belt,
18... Fixed guide, 19... Spout, 20... Probe, 22, 44b... Tapered surface, 23, 45... Fixed water supply element, 24... Gap, 25... Water column, 32 _-1 , 32
_-2 ...Holding frame, 33, 33'...Rotating shaft, 34
... Arm, 35... Spherical bearing, 37, 37'... Probe head, 39... Balance weight, 40... Bellows, 43... Water column chamber, 44... Rotating water supply element.

Claims (1)

[Scope of Claims] 1. In a rotary probe holder attached to a probe rotating type flaw detector, the rotary probe holder is mounted on a rotating probe rotor with a rotation axis provided on a rotating holding frame attached to the rotor of the flaw detector as the central axis. An arm is provided that swings toward and from the inspection material, and one end of the arm is provided with a rod having a spherical bearing at the tip, and the other end is provided with a balance weight, so that less than half the circumference of the inspection material is covered. The probe head, which has a covering cylindrical surface and has a required number of probes attached facing the material to be inspected, is engaged with the spherical bearing and opens in the shape of a flap in the direction in which the material to be inspected enters. and the probe head is pressed against the material to be inspected by the centrifugal force generated in the balance weight as the rotor of the flaw detector rotates when the material to be inspected enters the probe. Probe holder for rotating ultrasonic flaw detector.