JP7315345B2 - Anchor bolt ultrasonic flaw detection device and anchor bolt ultrasonic flaw detection method - Google Patents

Description

The present invention relates to an ultrasonic probe, an ultrasonic flaw detection apparatus for anchor bolts, and an ultrasonic flaw detection method for anchor bolts, and more particularly to an ultrasonic probe, an ultrasonic flaw detection apparatus for anchor bolts, and an ultrasonic flaw detection method for anchor bolts, which can inspect deterioration of bolts in invisible portions of anchor bolts without destroying concrete embedded portions.

A conventional anchor bolt ultrasonic inspection method is described, for example, in Japanese Patent No. 6088088 (Patent Document 1). According to the publication, the anchor bolt ultrasonic inspection apparatus inspects the corroded portion of the anchor bolt 27 using an ultrasonic probe (hereinafter sometimes referred to as "probe", "vertical probe", etc.). The anchor bolt ultrasonic inspection apparatus includes a cylindrical probe mounting portion that can be attached to the head of the anchor bolt and has a cylindrical inclined surface on which an ultrasonic probe can be mounted, a probe rotating jig that rotatably holds the probe mounting portion, and a digital ultrasonic flaw detector that receives a reflected echo of an ultrasonic flaw detection signal from the ultrasonic probe and determines deterioration of the anchor bolt.

Japanese Patent No. 6088088

A conventional anchor bolt ultrasonic inspection has been performed as described above. Although this method can sufficiently determine deterioration, the inspection range of the probe used was limited, so if the dimension in the flaw detection direction was large, it was sometimes necessary to replace the probe between the shallow range (short range) and the deep range (long range) for inspection.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems described above, and it is an object of the present invention to provide an ultrasonic probe, an ultrasonic testing apparatus for anchor bolts, and an ultrasonic testing method for anchor bolts, which are capable of inspecting deterioration of bolts without exchanging the probe even when the dimension in the testing direction is large.

The anchor bolt ultrasonic inspection apparatus according to the present invention uses an ultrasonic probe to inspect corroded portions of anchor bolts. An anchor bolt ultrasonic inspection apparatus is attachable to the head of an anchor bolt, and includes a cylindrical probe mounting portion having a sloped surface on which an ultrasonic probe can be attached to the top thereof, and deterioration determination means for receiving a reflected echo of an ultrasonic flaw detection signal from the probe and determining deterioration of the anchor bolt. A curved transducer having a second curvature.

Preferably, the curved transducer has a first angle of refraction and a second angle of refraction different from the first in the first direction.

More preferably, the curved transducer has a smoothly continuous refraction angle from the first refraction angle to the second refraction angle.

The curved transducer may be circular when viewed from a third direction different from the first and second directions.

An embodiment of the present invention includes a probe rotating jig that rotatably holds a probe mounting portion. The probe rotating jig includes a cylindrical rotating portion having a helical groove on its outer periphery, and a cylindrical pushing portion provided movably downward along the outer periphery of the rotating portion. , thereby rotating the probe, and the probe rotating jig is urged upward in the axial direction by a spring.

In another curved aspect of the present invention, an ultrasonic probe used in an anchor bolt ultrasonic testing apparatus for inspecting corroded portions of anchor bolts has a curved vibrator having a first curvature that changes a refraction angle in a first direction in which ultrasonic waves are emitted and a second curvature for line focusing in a second direction that intersects the first direction.

In still another curved aspect of the present invention, an anchor bolt ultrasonic testing method for inspecting a corroded portion of an anchor bolt using an ultrasonic probe is provided with a probe rotating jig having a probe mounting portion in which a line-focusing ultrasonic probe is attached at an angle with respect to the axis of the anchor bolt to the head of the anchor bolt, the probe rotating jig being capable of rotating the probe mounting portion around the axis of the anchor bolt when pushed in the axial direction of the anchor bolt. is pushed in the axial direction of the anchor bolt, and the probe mounting portion is rotated around the axis of the anchor bolt to receive ultrasonic flaw detection signals from the probe and determine deterioration of the anchor bolt.

According to this invention, a curved surface transducer having a curvature that changes the refraction angle in the incident direction of the ultrasonic wave is used as the transducer to detect flaws in the flaw detection portion. As a result, it is possible to provide an anchor bolt ultrasonic flaw detection method and apparatus capable of inspecting deterioration of a bolt without exchanging the probe even if the dimension in the depth direction is large.

FIG. 5 is a diagram showing a method of inspecting a shallow inspection range and a deep inspection range using a conventional focused probe; It is a schematic diagram which shows the whole structure of an anchor bolt ultrasonic testing apparatus. FIG. 4 is a diagram showing an inspection range of a line-focusing probe; FIG. 2 is a diagram showing the configuration of a probe including curved transducers according to this embodiment; FIG. 10 is a diagram showing flaw detection waveforms when a shallow range and a deep range are separately inspected for an M42 anchor bolt. FIG. 10 is a diagram showing a waveform of a flaw detection when an M42 anchor bolt is inspected using the probe of this embodiment; FIG. 10 is a diagram showing flaw detection waveforms when a shallow range and a deep range are separately inspected for an M36 anchor bolt. FIG. 10 is a diagram showing a waveform of a flaw detection when an M36 anchor bolt is inspected using the probe of this embodiment; It is a figure which shows the outline|summary of the rotation jig which concerns on this embodiment.

An embodiment of the present invention will be described below with reference to the drawings. First, a method for inspecting a shallow inspection range (inspection range (shallow) in the figure) and a deep inspection range (inspection range (deep) in the figure) of the anchor bolt 27 using an anchor bolt ultrasonic inspection apparatus as disclosed in the conventional patent document 1 will be described. FIG. 1A is a diagram showing a method of inspecting a shallow inspection range and a deep inspection range using a conventional focused probe 16. FIG.

It is a figure for demonstrating this range. FIG. 1A is a diagram showing the embedded state of the anchor bolt 27 and the mounting position of the probe 16. FIG.

Referring to FIG. 1(A), anchor bolts 27 are embedded in base concrete 31 here. As shown in FIG. 1A, level-adjusting mortar 33 may be applied between foundation concrete 31 and base plate 32 . Corrosion may cause thread loss at these locations. In a conventional device, a shallow range A such as the range above the base plate 32 and a deep range B such as the range below the base plate 32 cannot be inspected with one ultrasonic probe, and it was necessary to replace the probe. FIG. 1(B) shows the distances from the top of the bolt head in the shallow range A and the deep range B as inspection ranges, and the corresponding inspection ranges made possible in this embodiment for each anchor bolt size.

Here, FIG. 1B is a diagram showing the inspection range (distance (mm) from the top of the bolt) for each size of the anchor bolt 27. As shown in FIG. That is, for example, in the case of an M30 bolt, inspection is performed by exchanging probes in a range of up to 110 mm from the top of the bolt head and in a range of more than that, and for M33 to M42, inspection is performed by exchanging probes in a shallow range and a deep range shown in FIG.

That is, in this embodiment, it becomes possible to inspect the shallow range A and the deep range B, which were conventionally required, with one probe 16 .

Next, the configuration of the anchor bolt ultrasonic inspection apparatus 10 according to this embodiment will be described. FIG. 2 is a schematic diagram showing the configuration of an anchor bolt ultrasonic inspection apparatus 10 according to this embodiment. Referring to FIG. 2, the configuration of the anchor bolt ultrasonic inspection apparatus 10 is basically the same as that of the inspection apparatus disclosed in Patent Document 1, and the configuration of the probe used is different. Referring to FIG. 2, anchor bolt ultrasonic testing apparatus 10 according to this embodiment uses a probe for extensive inspection as probe 16 .

An angle wedge 17 is attached to the probe 16, and ultrasonic waves are obliquely incident. In this state, the probe 16 and the probe rotating jig 11 are used to inspect the anchor bolt 27 once in the circumferential direction.

The probe rotating jig 11 includes a rotating mechanism 12 consisting of a pushing portion 12a and a rotating portion 12b for rotating the vertical probe 16, a cylindrical vertical probe accommodating portion 13 having a circular upper end fixed to the lower end portion of the rotating mechanism 12 and accommodating the vertical probe 16 therein, and a guide portion 14 attached to the head of the anchor bolt 27 and guiding the vertical probe accommodating portion 13 in the axial direction.

The vertical probe housing portion 13 includes an upper end portion 13a, a cylindrical portion 13b extending downward from the upper end portion 13a and housing the vertical probe 16 therein, and an outer peripheral ring 13c provided on the outer periphery of the lower end portion of the cylindrical portion 13b.

The guide portion 14 includes an upper end portion 14a having a through hole in the center through which the cylindrical portion 13b penetrates, and a cylindrical portion 14b extending downward from the upper end portion 14a and surrounding the head of the anchor bolt from the outside.

A digital ultrasonic flaw detector 20, which is connected to the vertical probe 16 and analyzes data therefrom, is equipped with anchor bolt corrosion investigation application software 21, and is capable of setting flaw detection conditions, displaying flaw detection results, and the like.

A digital ultrasonic flaw detector 20 that is connected to the vertical probe 16 and analyzes data therefrom is equipped with anchor bolt corrosion investigation application software 21, and is capable of setting flaw detection conditions and displaying flaw detection results, as in Patent Document 1.

Also, the vertical probe 16 was fixed to the upper end surface of the angle wedge 17 . Here, the angle wedge 17 has a cylindrical shape having an inclined surface inclined at a predetermined angle at its upper end, and has a shape that can be attached to the upper end of the anchor bolt 27 . Here, the tilt angle is selected to be the optimum angle for inspecting a wide range of inspection target portions at once. Since the optimum angle varies depending on the diameter of the anchor bolt and the pitch shape and dimensions of the screw thread, a plurality of angle wedges 17 are prepared in advance and can be replaced as necessary.

Further, conventionally, as described above, two types, one for the shallow range A and the other for the deep range B, were required for each size of the anchor bolt.

Next, the probe used in this embodiment will be explained. FIG. 3 is a diagram for explaining the sound pressure level difference of an ultrasonic beam when using a line-focusing probe according to an embodiment of the present invention.

3(A) is a view showing the spread of an ultrasonic beam when using a line-focusing probe according to an embodiment of the present invention, FIG. 3(B) is an arrow view of a portion indicated by arrows IIIB-IIIB in FIG. It is a figure which shows. In FIG. 3(C), the X-axis is the sound pressure, the right direction is higher, and the Y-axis is the depth of the anchor bolt. Note that the corresponding range is indicated by a dotted line.

In this embodiment, since the line-focusing probe 16 is used, as shown in FIG. 3(B), there is a focal point c of the ultrasonic wave at a predetermined position from the top of the anchor bolt 27, and the range of flaw detection is the range of depths d to e below this position, and the sound pressure level is in the range of d1 to e1.

As shown in the figure, the range of flaw detection is depth d to e, and the position is deeper than the position shown in the conventional patent document 1. FIG. This is possible because the line-focusing probe 16 is used, so at the focusing point c, a higher sound pressure than in the conventional case is obtained, and the same level as the conventional sound pressure level is obtained in the deep range from d1 to e1 as shown in FIG. 3 (C).

Next, details of the probe of the flaw detector according to this embodiment will be described. In this embodiment, a line-focusing probe 16 with a frequency of 5 MHz is used to inspect deeper locations. A line-focusing probe is usually used by bending the transducer in a direction orthogonal to the propagation direction of the ultrasonic wave to focus the beam. In this embodiment, the transducer is curved in a direction parallel to the propagation direction of the ultrasonic wave (indicated by f in the figure) (as shown in the figure, the bending makes it possible to focus the direction of the sound wave so that it coincides with f), making it possible to enter the ultrasonic beam with high sound pressure deep into the anchor bolt. By increasing the size from 4 mm to 20 mm or more, the inspection range was expanded.

A line-focusing probe is originally used for the purpose of focusing an ultrasonic beam on the spot to be inspected and improving the detectability (S/N ratio), but this time, as explained in Fig. 3, a beam deeper than the focus point of the line-focusing probe is used to inspect the area corresponding to the level adjustment mortar construction site of the anchor bolt.

In addition, the direction of the ultrasonic beam to be focused is the direction perpendicular to the axial direction of the anchor bolt, and the ultrasonic beam with high sound pressure is applied to the depth below the focus point.

Next, a specific shape of the probe will be described. FIG. 4 is a diagram showing a specific configuration of the probe 16 according to this embodiment. 4A is a plan view of the curved transducer 18 that constitutes the probe 16, FIG. 4B is an elevational view showing specific dimensions including a cross-sectional view of the curved transducer 18 in the portion indicated by arrow IVB-IVB in FIG. 4A, FIG. 4C is a cross-sectional view of the portion indicated by arrow IVC-IVC in FIG. 4A, and FIG.

An ultrasonic probe according to the present invention has a curved transducer having a first curvature that changes a refraction angle in a first direction in which ultrasonic waves are emitted.

A conventional vibrator has a planar shape with a specific refraction angle, but in this embodiment, the vibrator is a curved vibrator 18 having a curved surface, as shown in FIGS. 4(A) to 4(C). The curved transducer 18 has an upwardly convex circular shape, and has a curvature R1 centered on a center 19 that changes the angle of refraction in a first direction, which is the direction of incidence of ultrasonic waves (flaw detection direction), and a curvature R2 for line focusing in a second direction that intersects with the first direction.

As shown in FIG. 4(B), in this example, the curvature R1 of the curved transducer 18 is set to 365 mm, and d is set to 20 mm from the position c=12 mm away from the center of curvature. Therefore, the angle e in the figure is 3.4 degrees, and as shown in FIG. 11 degrees is the angle for detecting shallow areas and 4 degrees is the angle for detecting deep areas.

In this embodiment, an example in which the refraction angle varies from 4 degrees to 11 degrees is shown, but the angle is not limited to this and may be set within a desired angle range.

Next, a flaw detection waveform obtained by a specific probe will be described. FIG. 5 is a diagram showing a shallow-range flaw detection waveform (A) (inspection range 70 mm to 150 mm) and a deep-range flaw detection waveform (B) (inspection range 100 mm to 250 mm) obtained with a conventional ultrasonic probe in an M42 anchor bolt, and FIG. In the figure, the X-axis is the depth direction distance of the anchor bolt, and the Y-axis is the amplitude of the echo obtained. Comparing FIGS. 5A and 5B with FIG. 6, it can be seen that the flaw detection waveform of FIG. 6 covers both the ranges of FIGS. 5A and 5B.

Next, another example will be described. FIG. 7 is a diagram showing a shallow-range flaw detection waveform (A) (inspection range 60 mm to 130 mm) and a deep-range flaw detection waveform (B) (inspection range 100 mm to 210 mm) obtained with a conventional ultrasonic probe in an M36 anchor bolt, and FIG. In the figure, the X-axis is the depth direction distance of the anchor bolt, and the Y-axis is the amplitude of the echo obtained. Comparing FIGS. 7A and 7B with FIG. 8, it can be seen that the flaw detection waveform in FIG. 8 covers the range of both FIGS. 7A and 7B.

As described above, in this embodiment, inspection from a shallow range to a deep range can be performed with a single probe without switching between a shallow range probe and a deep range probe, which has been necessary in the past.

Next, the rotary jig in this embodiment will be explained. In the system of Patent Document 1, the push-in portion of the rotary jig is manually pushed in, and the cylindrical cam inside the rotary jig rotates once in accordance with the movement of the push-in portion. As an issue during inspection, there were cases where stable flaw detection data could not be acquired due to shaking of the rotating jig when pushing it in manually. Therefore, in this embodiment, the structure is improved so that the rotary jig is not touched during data acquisition.

FIG. 9 is a diagram showing the configuration of the pushing portion of the inspection jig. 9A, the rotating jig 11 attached to the anchor bolt 27 includes a pushing portion 12a, a spring 41 attached to the jig 11, an air damper 43, an ultrasonic probe cable 44, a bolt tightening portion component (fixing jig) 46, an air adjustment nozzle 47, and a cylindrical cam 48. The anchor bolt 27 is fixed to the base plate 32 with a nut 45. Here, when the push-in portion 12a is pushed, the probe 16 rotates once.

In this embodiment, a spring 41 is provided inside the rotating jig 11, the spring 41 is pushed by the pushing portion 12a, and when the hand is released, the pushing portion 12a is lifted by the returning force of the spring 41, causing the internal cylindrical cam 48 to make one turn. In addition, after the flaw detection data is acquired when the probe 16 rotates once, the system performs the following processing within the system in order to display the acquired flaw detection data as a 0 to 360 degree developed view.

The number of acquired flaw detection data for one round is divided by the time required for the probe to make one round. For this reason, it is necessary to return the indentation at a constant speed. Therefore, an air damper 43 is incorporated in the rotary jig 11, and adjustment is made so that the force of the spring 41 causes the push-in portion 12a to return at a constant speed.
As described above, there is no need to touch the rotating jig when acquiring flaw detection data (no need to apply extra force), and stable data acquisition is possible. In addition, even if different inspectors operate the probe, the probe makes one revolution at a constant speed, eliminating variations in data acquisition by inspectors.

Although embodiments of the invention have been described with reference to the drawings, the invention is not limited to the illustrated embodiments. Various modifications can be made to the illustrated embodiment within the same scope as the present invention or within an equivalent scope.

According to the present invention, since the vibrator is curved to have different angles of refraction to detect flaws in the flaw detection portion, it is possible to provide an anchor bolt ultrasonic flaw detection method and device capable of inspecting deterioration of bolts without exchanging the probe by changing the refraction angle used by the transducer, even if the dimension in the depth direction is large.

10 Anchor bolt inspection device 11 Probe rotating jig 12 Rotating mechanism 12a Pushing part 12b Rotating part 13 Vertical probe housing part 13a Upper end part 13b Cylindrical part 13c Peripheral ring 14 Guide part 15 Inspection part 16 Vertical probe 17 Angle wedge 18 Curved transducer 19 Center 20 Digital ultrasonic flaw detector 21 Anchor bolt corrosion investigation application software, 25 concrete, 26 base plate, 27 anchor bolt.

Claims (5)

An anchor bolt ultrasonic inspection apparatus for inspecting corroded parts of anchor bolts using an ultrasonic probe,
A probe mounting portion that can be mounted on the head of the anchor bolt and has a cylindrical shape with an inclined surface on which the ultrasonic probe can be mounted at the top;
Deterioration determination means for determining deterioration of the anchor bolt by receiving a reflected echo of an ultrasonic flaw detection signal from the ultrasonic probe, the ultrasonic probe having a curved transducer having a first curvature that changes a refraction angle in a first direction in which the ultrasonic wave is emitted and a second curvature for line focusing in a second direction that intersects the first direction,
The ultrasonic inspection apparatus for anchor bolts, wherein the curved transducer has a circular shape when viewed from a third direction, which is an axial direction of the anchor bolt, different from the first and second directions. 2. The anchor bolt ultrasonic testing apparatus according to claim 1, wherein said curved transducer has a first angle of refraction and a second angle of refraction different from the first angle in said first direction. 3. The anchor bolt ultrasonic inspection apparatus according to claim 2, wherein said curved transducer has a smoothly continuous refraction angle from said first refraction angle to said second refraction angle. Including a probe rotating jig that rotatably holds the probe mounting part,
The probe rotating jig includes a cylindrical rotating portion having a spiral groove on its outer periphery,
a cylindrical push-in portion provided movably downward along the outer circumference of the rotating portion;
The pushing part has an engaging part on the inner circumference that can be engaged with the spiral groove of the rotating part, and when pushed downward, the engaging part moves downward while rotating along the groove, thereby rotating the ultrasonic probe,
4. The anchor bolt ultrasonic testing apparatus according to claim 1, wherein said probe rotating jig is biased upward in the axial direction by a spring. An anchor bolt ultrasonic flaw detection method for inspecting a corroded portion of an anchor bolt using an ultrasonic probe,
Attaching to the head of the anchor bolt a probe rotating jig having a probe mounting portion in which a line-focusing ultrasonic probe is attached at an angle with respect to the axis of the anchor bolt,
The probe rotating jig is capable of rotating the probe mounting portion around the axis of the anchor bolt when pushed in the axial direction of the anchor bolt,
By pushing the probe rotating jig in the axial direction of the anchor bolt and rotating the probe mounting portion around the axis of the anchor bolt, ultrasonic flaw detection signals from the probe are received to determine deterioration of the anchor bolt,
The ultrasonic probe has a curved transducer having a first curvature that changes the refraction angle in a first direction in which ultrasonic waves are emitted and a second curvature for line focusing in a second direction that intersects the first direction,
A method for ultrasonic inspection of anchor bolts, wherein the curved transducer is circular when viewed from a third direction, which is the axial direction of the anchor bolt, different from the first and second directions.

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