JP2004020549A - Method and device for bolt flaw detection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bolt flaw detecting method capable of more accurately detecting cracks on a bolt in a flaw examination test of serving bolt. <P>SOLUTION: This bolt flaw detecting method includes a step for filling a hole (5) axially-opened on a bolt (1) with a liquid (4), a step for inserting probes (2, 3) into the hole (5), and a step for conducting an ultrasonic test of the bolt (1) from inner surface of the hole (5). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a bolt flaw detection method and a flaw detection apparatus, and more particularly to a bolt flaw detection method and a flaw detection apparatus used in a turbine casing.
[0002]
[Prior art]
In many cases, a bolt inspection test is performed from the outer surface of the bolt after the bolt is pulled out. However, in order to pull out the bolt, the device in which the bolt is used must be stopped. If the device cannot be shut down, a flaw detection test of the bolt in use may be performed.
[0003]
A conventional ultrasonic flaw detection method for a bolt in use will be described with reference to FIG. FIG. 6 shows a cross section of a portion where the members 131a and 131b are fixed by the bolts 101 and the nuts 130a and 130b.
[0004]
A tensile stress is applied to the bolt 101 in the axial direction, and a crack 106 may be generated. Further, in the bolt 101 used for a turbine or the like, a crack 106 may be generated due to vibration or the like. In order to detect such a crack 106, an ultrasonic flaw detector using ultrasonic waves may be used.
[0005]
A conventional ultrasonic flaw detector includes a flaw detector main body 120 and a probe 107. The probe 107 used in this inspection generates an ultrasonic wave substantially perpendicular to the flaw detection surface. The probe 107 has an ultrasonic generating unit and a receiving unit integrated with each other.
[0006]
In this ultrasonic flaw detector, an ultrasonic wave is transmitted from a probe 107 applied to one end of a bolt 101 to a contact surface, and the ultrasonic wave reflected by a crack 106 or the like is received by the probe 107. Thus, the crack 106 is detected. Specifically, the ultrasonic wave transmitted from the probe 107 to the end of the bolt 101 in the axial direction is reflected by the crack 106 rather than reflected by the other end and received by the probe 107. Since the reception at 107 is earlier, the presence or absence of the crack 106 is detected. Further, since the speed of the ultrasonic wave in the bolt is known, the position of the crack 106 is detected by the time at which the ultrasonic wave reflected by the crack 106 is received. The length of the crack is detected by moving the probe 107 on the end face of the bolt 101 and measuring at each point.
[0007]
Such a conventional ultrasonic flaw detection method may not be able to detect a small crack 106 when affected by the shape of the bolt side surface. It is also difficult to detect the depth (length) of the crack 106.
[0008]
Japanese Patent Application Laid-Open No. 2000-121609 discloses an invention in which a probe 107 is applied to an end of a bolt 101 to detect a crack 106.
[0009]
A bolt fixing the casing roof to the turbine casing main body may be provided with a hole in the longitudinal direction at the center of the bolt axis for the following reason.
Bolts attached to the turbine casing main body have a large diameter and are tightened with a large force, so that it is difficult to loosen them. In order to loosen such a bolt, the bolt may be heated and loosened with the bolt stretched. In order to uniformly heat the entire bolt, a heater inserted into the center axis of the bolt is used. A center hole is made in the longitudinal direction of the bolt about the axis of the bolt to insert the heater. Normally, this center hole is not used except when the heater is inserted.
[0010]
In a flaw detection inspection of a bolt in use, there is a demand for an ultrasonic flaw detector capable of detecting a crack of a bolt with higher accuracy by using a center hole of the bolt.
An ultrasonic flaw detector capable of accurately detecting the size of a bolt crack is desired.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to provide an ultrasonic flaw detection method or a flaw detection method device capable of detecting a crack of a bolt with higher accuracy in a flaw detection inspection of a bolt in use.
[0012]
[Means for Solving the Problems]
The means for solving the problem will be described below using the numbers and symbols used in [Embodiments of the Invention]. These numbers and symbols are added to clarify the correspondence between the description of [Claims] and the description of [Embodiments of the Invention]. It should not be used to interpret the technical scope of the described invention.
[0013]
The bolt inspection method according to the present invention includes a step of inserting a probe (2, 3) into a hole (5) formed in an axial direction of a bolt (1), and a step of inserting a bolt (1) from an inner surface of the hole (5). Performing a test of
[0014]
A bolt flaw detection method according to the present invention comprises the steps of: filling a hole (5) formed in an axial direction of a bolt (1) with a liquid (4); and inserting probes (2, 3) into the hole (5). Performing the ultrasonic inspection of the bolt (1) from the inner surface of the hole (5).
[0015]
Further, the probe (2, 3) of the bolt flaw detection method according to the present invention includes a separated reception probe (3) and a transmission probe (2), and the ultrasonic flaw detection is performed by a TOFD method. Flaw detection inspection.
[0016]
Further, the step of inserting the probe (2, 3) of the bolt flaw detection method according to the present invention includes the step of mounting the receiving probe (3) and the transmitting probe (2) at a known interval. And inserting the inspection jig (10) into the hole (5).
[0017]
A jig for bolt ultrasonic inspection (10) of the present invention comprises a jig body (16), a receiving probe (13) and a transmitting probe attached to the jig body (16) at known intervals. (12).
[0018]
A jig for bolt ultrasonic inspection (10) of the present invention comprises a jig body (16), a receiving probe (13) and a transmitting probe attached to the jig body (16) at known intervals. Probe (12), a sound wave transmitting surface of the transmitting probe (12), a sound wave receiving surface of the receiving probe (13), and an inner surface of a hole (5) formed in the axial direction of the bolt (1). Wedges (14a, 14b) installed between the bolts (1) and alignment jigs (14) mounted along the inner surfaces of the holes (5) formed in the axial direction of the bolt (1). 15a, 15b).
[0019]
A bolt flaw detector of the present invention includes any one of the bolt ultrasonic flaw detection jigs (10) described above.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a flaw detector according to the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows an outline of the bolt flaw detection method of the present invention.
[0021]
Bolts 1 fix the casing roof to the turbine casing body. The bolt 1 has a center hole 5 in the longitudinal direction of the bolt centered on the bolt axis. Originally, the center hole 5 is a hole for inserting a heater for warming and extending the bolt when the bolt is loosened.
[0022]
In the present invention, a flaw detection test of the bolt 1 in use is performed using the center hole 5.
[0023]
As a flaw detection method, a so-called TOFD (Time of Flight Diffraction) method is used.
In the TOFD method, a transmitting probe 2 and a receiving probe 3 are used. The transmitting probe 2 and the receiving probe 3 are installed at intervals determined by the thickness of the object to be measured and the angle at which the ultrasonic waves are transmitted. The transmitting probe 2 transmits an ultrasonic wave, and the receiving probe 3 receives the ultrasonic wave reflected or diffracted by a defect or a flaw. The position and size of the defect can be measured based on the time when the reflected or diffracted ultrasonic wave is received.
[0024]
The center hole 5 is filled with water 4 for ultrasonic wave propagation as a couplant. The substance to be filled as the couplant is not limited to water, and liquids and fluids that transmit ultrasonic waves can be used.
[0025]
The transmitting probe 2 and the receiving probe 3 are separated from each other by the distance determined by the refraction angle and the distance between the inner surface of the center hole 5 and the outer surface of the bolt 1 (hereinafter referred to as bolt thickness). It is inserted in the center hole 5 while being separated in the axial direction.
The angle (hereinafter referred to as the refraction angle) between the ultrasonic wave transmitted from the transmitting probe 2 and the inner surface of the center hole 5 is not perpendicular, and the ultrasonic wave is transmitted obliquely from the transmitting probe 2 to the inner surface.
[0026]
Ultrasonic waves are transmitted from the transmitting probe 2 to the bolt 1, and the ultrasonic waves reflected or diffracted by the outer surface of the bolt and the tip of the crack 6 are received by the receiving probe 3. Since the center hole 5 is filled with the water 4, ultrasonic waves can be transmitted even when the transmitting probe 2 and the receiving probe 3 do not contact the inner surface of the center hole 5.
When the ultrasonic wave reflected or diffracted at the tip of the crack 6 is received, the position of the crack 6 is detected by the position of the jig (10) for bolt flaw detection, and reflected or diffracted by the crack 6 and the outer surface of the bolt 1 or the like. The size of the crack 6 is detected based on the difference in time at which the ultrasonic waves are received.
[0027]
FIG. 2 shows an example of an ultrasonic wave received by the receiving probe 3. The horizontal axis indicates the reception time t, and the vertical axis indicates the level of the sound wave (echo) to be received.
Ultrasonic waves are transmitted from the transmitting probe 2 to the inner surface of the center hole 5 at a certain refraction angle.
The receiving probe 3 first receives the echo P1 from the inner surface of the center hole 5. Next, an echo P3 from the tip of the crack 6 is received. Further, an echo P2 from the outer surface of the bolt 1 is received. Since the velocity of the ultrasonic wave in the bolt (determined from the material of the bolt) and the distance between the transmitting probe 2 and the receiving probe 3 are known, the time difference between the echo P3 and the echo P2 indicates that the crack 6 Length is required.
[0028]
In the TOFD method, it is possible to detect even smaller cracks 6 as compared with the conventional method of transmitting ultrasonic waves vertically from the end face of the bolt. Further, the length of the crack 6 can be detected with higher accuracy than the conventional method.
[0029]
(Embodiment 1)
Referring to FIGS. 3 and 4, there is shown an example in which the above-described flaw detection method is used to perform flaw detection inspection of a bolt used in a turbine casing main body.
FIG. 3 shows an outline in which a bolt 1 for fixing the casing roof 31a to the turbine casing main body 32 is flaw-detected. FIG. 4 shows an outline of a jig with a probe 10 used for flaw detection.
A casing roof 31a is fixed to the turbine casing main body 32 by bolts 1. The bolt 1 is provided with a center hole 5 for inserting a heater for heating in the longitudinal direction about the bolt axis. The center hole 5 may be opened to the tip of the bolt 1 and penetrate the bolt 1, or may be partially opened.
The center hole 5 is filled with water 4 for ultrasonic wave propagation.
[0030]
The ultrasonic flaw detector includes a flaw detector main body 20 and a jig 10 with a probe.
The flaw detector main body 20 includes a display unit, an input unit, and a calculation unit. The display unit displays a processing result of the received sound wave and displays input conditions. The input unit includes keys and switches for inputting the distance between the probes, the material of the member to be measured, the speed of sound waves, and the like. The arithmetic unit controls the transmission of ultrasonic waves, calculates the presence or absence and position of the crack 6 from the condition input from the input unit and the signal of the received sound wave received from the receiving probe 13, It is possible to control to display a waveform or the like received by the touch element 13 on the display unit.
[0031]
The details of the jig 10 with a probe are shown in FIG.
FIG. 4A is a side view of the jig 10 with a probe. FIG. 4B is a cross section taken along the line AA ′ of the jig 10 with the probe.
[0032]
The jig with probe 10 includes a transmitting probe 12, a receiving probe 13, wedges 14a and 14b, alignment jigs 15a and 15b, a jig main body 16, and alignment members 17a and 17b.
[0033]
The transmitting probe 12 includes a vibrator, and generates an ultrasonic wave with a specific pulse under the control of the flaw detector main body 20. The transmitting probe 12 is selected and used according to the refraction angle of the transmitted ultrasonic wave.
The receiving probe 13 receives the reflected ultrasonic waves and transmits the ultrasonic waves to the flaw detector main body 20.
The transmitting probe 12 and the receiving probe 13 are attached to the jig main body 16 so as to be separated from each other in the axial direction of the bolt 1 by a distance determined by the refraction angle and the bolt thickness. The transmitting probe 12 and the receiving probe 13 are removable, and the interval between the transmitting probe 12 and the receiving probe 13 is adjustable. The transmitting probe 12 and the receiving probe 13 are connected to the flaw detector main body 20 by a cable or the like.
[0034]
The wedges 14a and 14b are made of a material such as acrylic, which transmits ultrasonic waves more easily than water. The wedges 14a and 14b fill the space between the transmitting surface of the transmitting probe 12, the receiving surface of the receiving probe 13 and the inner surface of the center hole 5, and transmit the transmitting probe 12 and the receiving probe. It is attached to the contact 13.
By reducing the path of ultrasonic waves passing through the water by the wedges 14a and 14b, or by bringing the wedges 14a and 14b into contact with the inner surface of the center hole 5, diffusion of ultrasonic waves in water and inner surface of the center hole 5 The spread of the ultrasonic wave can be suppressed, and the echo can be received with high accuracy. It is preferable that the wedges 14a and 14b have a convex curved surface at a portion facing the inner surface of the center hole 5 so as to contact the inner surface of the center hole 5 or reduce the interval between the inner surfaces of the center hole 5. Alternatively, the portions of the wedges 14a and 14b that contact the inner surface of the center hole 5 preferably have a curved surface or a spherical surface having a radius slightly smaller than the radius of the center hole 5. Further, it is preferable that the wedges 14a and 14b can be replaced according to the diameter of the center hole 5.
[0035]
The alignment jigs 15a and 15b are used to adjust the jig body 16 so as to be located at the center of the center hole 5, and to adjust the wedges 14a and 14b to contact or approach the inner surface of the center hole 5. It is a jig. In the jig 10 with a probe of this example, the alignment jigs 15 a and 15 b are attached to the jig main body 16 on the surface opposite to the wedges 14 a and 14 b with respect to the center axis of the jig main body 16. The alignment jigs 15a and 15b preferably have a curved surface or a spherical surface having a radius slightly smaller than the radius of the center hole 5. Further, it is preferable that the alignment jigs 15a and 15b can be adjusted in position with screws or the like or can be replaced according to the diameter of the center hole 5.
Alternatively, the centering jigs 15a and 15b are made of a deformable elastic body, and are attached so as to be elastically deformed between the jig main body 16 and the inner surface of the center hole 5, so that the wedges 14a and 14b are connected to the center holes 5a and 15b. It can also be mounted so that it can be pressed against the inner surface.
[0036]
On the jig body 16, the transmitting probe 12, the receiving probe 13, the wedges 14a and 14b, the alignment jigs 15a and 15b, and the alignment members 17a and 17b are attached.
[0037]
The alignment members 17a and 17b are respectively attached to both ends of the jig body 16 in the longitudinal direction. The centering members 17a and 17b are made of an elastic body or are made to be elastically deformed. When the jig 10 with the probe is inserted into the center hole 5, it is elastically deformed. It can be adjusted so that the center of the jig body 16 is inserted substantially straight into the center of the center hole 5. It is preferable that the portions of the alignment members 17a and 17b that come into contact with the inner surface of the center hole 5 have low sliding resistance for the movement of the jig 10 with the probe.
[0038]
It is preferable that a string or a rod be attached to the jig with probe 10 so that the measurer can change the position or direction of the jig with probe 10 in the center hole 5.
[0039]
The inspector inserts the jig 10 with the probe into the center hole 5 of the bolt 1 and moves it in the axial direction, or rotates around the center axis to detect the crack 6 of the bolt 1. be able to.
[0040]
(Embodiment 2)
As Embodiment 2, another embodiment of a jig 50 with a self-propelled probe will be described.
FIG. 5 shows an outer shape of the jig 50 with a self-propelled probe. 5A shows a view from one direction of a jig 50 with a self-propelled probe, and FIG. 5B shows a jig 50 with a self-propelled probe viewed from a B direction. c) shows the self-propelled jig with probe 50 viewed from the C direction.
[0041]
The self-propelled jig with a probe 50 can be self-propelled. The jig 50 with a self-propelled probe is inserted into the center hole 5 at the time of inspection. The self-propelled jig with a probe 50 is connected to the flaw detector main body 20 by a cable as in the jig with a probe 10 of the first embodiment. Power for power may be supplied from the flaw detection device main body 20 to the jig 50 with the self-propelled probe by a cable.
The self-propelled jig with probe 50 includes a transmitting probe 51a, a receiving probe 51b, wedges 52a and 52b, alignment jigs 55a and 55b, motors 54a and 54b, rotating bodies 53a and 53b, 53c, 53d, tracks 56a, 56b, and a jig main body 58 are provided.
[0042]
The transmitting probe 51a includes a vibrator, and generates an ultrasonic wave with a specific pulse under the control of the flaw detector main body 20. The transmitting probe 51a is selected and used according to the refraction angle of the transmitted ultrasonic wave.
The receiving probe 51b receives the reflected ultrasonic waves and transmits the ultrasonic waves to the flaw detector main body 20.
The transmission probe 51a and the reception probe 51b are attached to the jig main body 58 at an interval determined by the refraction angle and the bolt thickness in the axial direction of the bolt 1. The transmitting probe 51a and the receiving probe 51b are detachable, and the distance between the transmitting probe 51a and the receiving probe 51b is adjustable.
[0043]
Further, the transmitting probe 51a and the receiving probe 51b are configured to rotate around the longitudinal axis in accordance with the speed at which the jig 50 with the self-propelled probe advances. preferable. The transmission probe 51a and the reception probe 51b rotate by rotating a gear meshed with a gear that transmits rotation from the motors 54a and 54b to the rotating bodies 53a, 53b, 53c, and 53d. This is performed by transmitting the signals to the probe 51a and the receiving probe 51b.
The inspection range is dense by rotating the transmission probe 51a and the reception probe 51b faster with respect to the traveling speed of the jig 50 with the self-propelled probe, and the inspection range is reduced by rotating the probe 51a and the reception probe 51b slowly. It can be. The transmitting probe 51a and the receiving probe 51b are configured to rotate at the same speed in accordance with the moving speed of the jig 50 with the self-propelled probe. Since the rotation speed of each probe has a limit in performing the inspection, the moving speed of the jig 50 with the self-propelled probe is determined by the density of the inspection.
[0044]
The wedges 52a and 52b are made of a material such as acrylic, which transmits ultrasonic waves more easily than water. The wedges 52a and 52b are attached to the transmission probe 51a and the reception probe 51b so as to fill between the transmission probe 51a or the reception probe 51b and the inner surface of the center hole 5.
The wedges 52a and 52b reduce the path through which the ultrasonic waves pass through the water, or the wedges 52a and 52b come into contact with the inner surface of the center hole 5 to diffuse the ultrasonic waves in the water and to reduce the inner surface of the center hole 5. Can suppress the diffusion of the ultrasonic wave, and can receive the ultrasonic wave with high accuracy. It is preferable that the wedges 52a and 52b have a convex curved surface facing the inner surface of the center hole 5 so as to contact the inner surface of the center hole 5 or reduce the interval between the inner surfaces of the center hole 5. Alternatively, the surfaces of the wedges 52a and 52b facing the inner surface of the center hole 5 preferably have a curved surface or a spherical surface having a diameter slightly smaller than the inner diameter of the center hole 5. Further, it is preferable that the wedges 52a and 52b can be replaced according to the inner diameter of the center hole 5.
[0045]
The alignment jigs 55a and 55b are used to adjust the jig body 58 so as to be located at the center of the center hole 5 and to allow the wedges 52a and 52b to contact or approach the inner surface of the center hole 5. It is a jig. In the jig 50 with a self-propelled probe of the present example, the alignment jigs 55a and 55b are attached to the transmitting probe 51a and the receiving probe 51b at positions opposite to the wedges 52a and 52b. . The alignment jigs 55a and 55b preferably have a curved surface or a spherical surface having a radius slightly smaller than the radius of the center hole 5. Further, it is preferable that the alignment jigs 55a and 55b can be adjusted in position with screws or the like in accordance with the diameter of the center hole 5, or can be replaced.
Alternatively, the centering jigs 55a and 55b are made of a deformable elastic body, and are attached so as to be elastically deformed between the jig body 58 and the inner surface of the center hole 5, so that the wedges 52a and 52b are connected to the center holes 5a and 55b. Preferably, it can be pressed against the inner surface.
[0046]
The motors 54a and 54b generate rotational motion by rotation of the shaft. The rotating motion is transmitted to the rotating bodies 53a, 53b, 53c, 53d. The rotation is transmitted from the motors 54a, 54b to the rotating bodies 53a, 53b, 53c, 53d by gears (not shown). The transmission probe 51a and the reception probe 51b can be configured to rotate by meshing a gear that rotates the transmission probe 51a and the reception probe 51b with this gear. The motors 54a and 54b are small electric motors and are driven by batteries (not shown) mounted on the self-propelled jig with probe 50 or by supply of electricity from cables. Although two motors are used in this embodiment, one motor may be used.
[0047]
The rotating bodies 53a, 53b, 53c, 53d are rotated by the power of motors 54a, 54b. The rotating bodies 53a and 53b, the rotating bodies 53c and the rotating bodies 53d are respectively attached in the same direction from the axis of the jig main body 58, and the rotating bodies 53a and 53c, and the rotating bodies 53b and 53d are Each of the jigs 50 with a self-propelled probe is attached to two rotation axes which are orthogonal to the longitudinal axis and are substantially parallel to each other. The caterpillars 56a, 56b are attached to the two rotating bodies 53a, 53b, 53c, 53d in the same direction.
Each of the rotating bodies 53a, 53b, 53c and 53d has the same size, and two points on the circumference of each of the rotating bodies are connected to the center hole 5 via the caterpillars 56a and 56b when the caterpillars 56a and 56b are attached. It is preferable that the size or the position is determined so as to be in contact with the inner surface of the.
The rotating bodies 53a, 53b, 53c, and 53d can be replaced according to the inner diameter of the center hole 5, or a jig with a self-propelled probe so that each of the tracks 56a and 56b fits the inner surface of the center hole 5. Preferably, the length from 50 longitudinal axes can be adjusted.
[0048]
Each of the caterpillars 56a, 56b is attached to two rotating bodies 53a, 53b, 53c, 53d in the same direction from the axis of the jig main body 58. As the rotating bodies 53a, 53b, 53c, 53d rotate, the tracks 56a, 56b rotate. By rotating the tracks 56a and 56b, the jig 50 with the self-propelled probe can move in the axial direction of the center hole 5.
[0049]
The jig body 58 includes a transmitting probe 51a, a receiving probe 51b, wedges 52a and 52b, alignment jigs 55a and 55b, motors 54a and 54b, rotating bodies 53a, 53b, 53c, 53d, and caterpillars. 56a, 56b are attached.
[0050]
It is preferable that the moving speed of the jig 50 with a self-propelled probe and the rotation speed of the transmitting probe 51a and the receiving probe 51b can be controlled by inputting a command to the flaw detector main body 20. When the crack 6 is detected, it is preferably programmed to automatically and closely inspect the periphery (reduce the moving speed).
The self-propelled jig with a probe 50 is preferably applied to a bolt 1 having a shaft mounted in a horizontal direction.
[0051]
In the above embodiment, the example in which the flaw detection inspection of the present invention is applied to the bolt of the turbine casing body in which the center hole 5 for the heater is opened has been described. Inspection can also be performed by opening a center hole 5 for inspection.
[0052]
Although the flaw detection test of the bolt 1 has been described in the above embodiment, the thickness inspection (corrosion test) of the bolt 1 is performed by measuring from the center hole 5 of the bolt 1 using a vertical ultrasonic probe. It can also be implemented.
[0053]
【The invention's effect】
ADVANTAGE OF THE INVENTION The ultrasonic flaw detection method and ultrasonic flaw detection method apparatus of this invention can detect a crack of a bolt more accurately in the flaw detection inspection of the bolt in use.
[Brief description of the drawings]
FIG. 1 shows an outline of a flaw detection method for a bolt according to the present invention by the TFDO method.
FIG. 2 shows an example of an ultrasonic wave received by a receiving probe 3;
FIG. 3 shows an outline in which a bolt 1 for fixing a casing roof 31a to a turbine casing main body 32 is inspected for flaws.
FIG. 4 shows an outline of a jig with a probe 10 used for flaw detection.
FIG. 5 shows an outline of a jig 50 with a self-propelled probe.
FIG. 6 shows an outline of a conventional bolt flaw detection method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bolt 2 Transmitting probe 3 Receiving probe 4 Water 5 Center hole 6 Crack 10 Jig with probe 12 Transmitting probe 13 Receiving probe 14a, 14b Wedge 15a, 15b Alignment Jig 16 Jig main body 17a, 17b Alignment member 20 Flaw detector main unit 31a (turbine) casing roof 32 (turbine) casing main body 50 Self-propelled probe-attached jig 51a Transmitting probe 51b Receiving probe Touch elements 52a, 52b Wedges 55a, 55b Alignment jigs 54a, 54b Motors 53a, 53b, 53c, 53d Rotating bodies 56a, 56b Caterpillar 58 Jig bodies P1, P2, P3, P4 Echo

Claims (7)

Inserting the probe into a hole drilled in the axial direction of the bolt;
Inspecting the bolt from the inner surface of the hole.
Bolt inspection method. Filling the bore in the axial direction of the bolt with liquid;
Inserting a probe into the hole;
Performing an ultrasonic inspection of the bolt from the inner surface of the hole.
Bolt inspection method. The probe includes a separated receiving probe and a transmitting probe,
The ultrasonic inspection is an inspection based on the TOFD method.
The method for detecting a bolt according to claim 2. The step of inserting the probe, the receiving probe and the transmitting probe, is a step of inserting an inspection jig mounted at a known interval, into the hole,
The bolt inspection method according to claim 3. Jig body,
A receiving probe and a transmitting probe attached to the jig body at known intervals,
Jig for ultrasonic inspection of bolts. Jig body,
The jig body, a receiving probe and a transmitting probe attached at known intervals,
A wedge attached between the sound wave transmitting surface of the transmitting probe and the sound wave receiving surface of the receiving probe, and an inner surface of a hole formed in the axial direction of the bolt,
A centering jig, wherein the wedge is mounted along the inner surface of a hole formed in the axial direction of the bolt,
Jig for ultrasonic inspection of bolts. A bolt ultrasonic flaw detection jig according to claim 5 or 6,
Bolt inspection equipment.

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