JP2009186446A - Method and system for flaw detection of turbine rotor blade groove portion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system used for the flaw detection of a turbine rotor blade groove portion which can be simplified and easily operated for shortening the time required for flaw detection. <P>SOLUTION: A flaw detection method of the turbine rotor blade groove portion is to detect the stress corrosion defects of rotor disk wing groove portion 2, containing a turbine blade root section 5 by using an ultrasonic detector probe 12. In this method, the rotor disk peripheral side shoulder 3 is set, facing the rotor disk wing groove portion 2 as a reference plane and contact the support 11 for supporting the ultrasonic detector probe 12 with this reference plane; then by making the ultrasonic detector probe 12 move circumferentially on the peripheral surface of the rotor disk 1, while contacting the support 11 with the reference plane, to detect stress corrosion defects of the rotor disk wing groove portion 2, by using the ultrasonic detector probe 12 with this ultrasonic detector probe 12 kept in the position facing the rotor disk wing groove portion 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flaw detection method and apparatus for a steam turbine rotor blade groove, which is applied to diagnosis of a deterioration state of a rotor of a high / medium pressure steam turbine in a power plant or the like.

  Since the rotor of a high / medium pressure steam turbine in a power plant is operated under a high temperature condition, stress corrosion cracking may occur in a portion subjected to stress when used for a long period of time. As a part which receives this stress, there are many shoulders of the turbine rotor blade groove in which the moving blade is implanted, and this part is an important part in evaluating the remaining life of the turbine rotor. However, since the blade is implanted in the blade groove and the blade root of the blade is fitted, it cannot be seen from the surface.

  8 and 9 are conceptual diagrams of a general steam turbine rotor. 8 and 9, a plurality of rotor disks 03 are integrally formed on the shaft 02 of the turbine rotor 01 so as to be concentric with the shaft 02, and a large number of blades 04 are arranged on the outer periphery of each rotor disk 03. It is attached to the shape. On the outer periphery of the rotor disk 03, there is provided a blade implantation portion 05 in which a blade groove for fitting the blade 04 is formed, and a large number of blades 04 are implanted in the blade implantation portion 05. As shown in FIG. 9, the rotor disk 03 rotates in the direction of arrow a.

  As a method for diagnosing such a blade groove part, a nondestructive defect detection method using ultrasonic waves has been conventionally employed. When performing hand flaw detection (manual scanning) using an ultrasonic flaw detection probe, it is necessary to detect the defect by fixing the flaw detection probe at a position where the ultrasonic wave reflected from the defect portion is maximum. At that time, a jig for holding the ultrasonic flaw detection probe in this position is required.

  Patent Document 1 (Japanese Patent No. 3808513) discloses a direction and apparatus for flaw detection by ultrasonic waves in a blade implantation groove of a disk of a steam turbine rotor. Hereinafter, the apparatus disclosed in Patent Document 1 will be described with reference to FIGS. 10 and 11.

  FIG. 10 is a front view of the ultrasonic flaw detector, and FIG. 11 is a side view thereof, showing a state in which the ultrasonic flaw detector is attached to the turbine rotor 01 to be inspected. 10 and 11, a grooved roller that engages with a guide rail 021 that is laid in the circumferential direction on the outer periphery of the rotor shaft 02 and rolls along the guide rail 021 is provided below the ultrasonic probe holder 020. 022 and a roller 023 are provided.

  A groove 022a that engages with the unevenness of the guide rail 021 is formed on the outer periphery of the grooved roller 022, and a gear 024 is formed integrally with the grooved roller 022. The gear 024 is meshed with a gear 025 a connected to the rotary encoder 025, and the rotation of the grooved roller 022 is transmitted to the rotary encoder 025. The output of the rotary encoder 025 is displayed on a position reading device (not shown).

  A long hole 026 extending in the radial direction of the shaft 02 is formed in the ultrasonic flaw detector holder 020, and a holding mechanism 028 for holding the ultrasonic flaw detection probe 027 is slidably mounted in the long hole 026. By moving the holding mechanism 028 along the long hole 026, the position Lp in the radial direction with respect to the rotor disk 03 is adjusted while the ultrasonic flaw detection probe 027 is in close contact with the rotor disk 03. Further, the ultrasonic flaw detection probe 027 is held so as to be swingable with respect to the holding mechanism 028, and the direction of the ultrasonic beam γ transmitted from the ultrasonic flaw detection probe 027 is changed so that the swing angle A is suitable for the inspection. It can be set.

  With this configuration, ultrasonic flaw detectors are arranged on both sides of the rotor disk 03 to be inspected, and one ultrasonic flaw detector is applied to the blade implantation groove 05 of the turbine rotor 01 while moving the ultrasonic flaw detector on the die rail 021. An ultrasonic beam γ is incident on the rotor disk 03 from the machine, and the reflected ultrasonic beam is received by the other ultrasonic flaw detector, thereby detecting a defect in the blade implantation part 05. Note that a hand grip 029 for manually moving the ultrasonic flaw detector holder 020 is attached to the ultrasonic flaw detector holder 020.

Japanese Patent No. 3808513

In the ultrasonic flaw detector disclosed in Patent Document 1, a guide rail 021 with a groove must be provided on the outer periphery of the rotor shaft 02, and the ultrasonic flaw detector holder 020 itself is also implanted into the blade from the rotor shaft 02. Since it is necessary to make it the magnitude | size which straddles the groove part 05, it enlarges and it becomes high cost. When the diameter of the rotor disk 03 is increased to 2 to 3 m, the ultrasonic flaw detector holder 020 has a length of 1 m or more.
For this reason, it takes time to operate the ultrasonic flaw detector, and there is a problem that it takes a long time to detect a defect in the turbine rotor blade groove.

  Further, since the ultrasonic flaw detector does not have a jig for holding the ultrasonic flaw detection probe at a position where the ultrasonic wave reflected from the defective portion is maximum, it takes time for flaw detection.

  In view of the problems of the prior art, the present invention makes it possible to reduce the time required for defect detection and reduce the cost by simplifying the apparatus used for detecting defects in the turbine rotor blade groove and facilitating the operation thereof. Objective.

In order to achieve the above object, a method for flaw detection in a turbine rotor blade groove of the present invention is as follows.
In a turbine rotor blade groove flaw detection method for detecting stress corrosion defects in a rotor disk blade groove portion containing a turbine blade blade root using an ultrasonic flaw detection probe,
With the shoulder on the outer periphery of the rotor disk facing the rotor disk blade groove as a reference plane, a support base that supports the ultrasonic flaw detection probe is brought into contact with the reference plane,
Stress corrosion of the rotor disk blade groove part while holding the support base in contact with the reference surface and holding the ultrasonic flaw detection probe in a circumferential direction on the outer surface of the rotor disk so as to face the rotor disk blade groove part. A defect is detected.

  In the method of the present invention, using a shoulder portion (inclined surface or stepped portion) existing on the outer peripheral surface of the rotor disk, using the shoulder portion as a reference surface, the support for the ultrasonic flaw detection probe is brought into contact with the reference surface, The ultrasonic flaw detection probe is moved on the outer circumferential surface of the rotor disk while being held at a position facing the rotor disk blade groove. These operations can be performed by a worker's hand, and no special jig is required. During this movement, ultrasonic waves are incident from the ultrasonic flaw detection probe toward the rotor disk blade groove.

  The ultrasonic wave incident on the rotor disk blade groove is reflected by a defect such as a crack caused by stress corrosion cracking. By receiving this reflected ultrasonic wave with the ultrasonic flaw detection probe, a defect in the rotor disk blade groove is detected.

  According to the method of the present invention, the ultrasonic flaw detection probe support is slidably brought into contact with the shoulder portion present on the outer peripheral surface of the rotor disk, so that positioning of the ultrasonic flaw detection probe can be performed without requiring a separate positioning jig. Is possible. Therefore, the flaw detection apparatus can be simplified and the cost can be reduced. Then, by placing the ultrasonic flaw detection probe along the shoulder, the ultrasonic flaw detection probe can be held at a position facing the rotor disk blade groove portion, so that the ultrasonic wave reflected from the defective portion of the rotor disk blade groove portion is maximized. The ultrasonic flaw detection probe can be positioned at the position.

  Further, since the shoulder portion exists over the entire circumference of the rotor disk, by placing an ultrasonic flaw detection probe along the shoulder section, defects in the entire blade groove portion provided over the entire circumference at the outer edge of the rotor disk. Enable detection.

  In the method of the present invention, not only the reflection echo method for detecting the defect part by receiving the ultrasonic wave reflected from the defect part generated in the blade groove part, the ultrasonic wave is concentrated and irradiated on both ends of the crack, and the end echo is emitted. Phased phase that makes it possible to visualize the defect by transmitting the ultrasonic waves from the end echo method and multiple ultrasonic transmitters, which can determine the length of the crack more accurately from the time (distance) difference received. An array method or the like can be performed.

  In the method of the present invention, if a magnetic attraction force is applied to the ultrasonic flaw detection probe support base and the reference surface, and the support base is held on the reference surface by the magnetic attraction force, the support surface is It can be slidably contacted with the reference surface, and manual scanning can be further stabilized.

  Further, when the shroud for connecting the outer ends of the plurality of turbine blades is provided, the ultrasonic test probe support base is supported at two points on at least one side surface of the shroud connecting the reference surface and the outer end of the turbine rotor blade. It is good to do so. Accordingly, the support base of the ultrasonic flaw detection probe can be further stably held, and the support base can be supported by the shroud, so that it is not necessary for an operator to support the support base. Therefore, manual scanning of ultrasonic flaw detection is further stabilized.

A flaw detector for a turbine rotor blade groove of the present invention for carrying out the method of the present invention comprises:
In a turbine rotor blade groove flaw detection apparatus for detecting stress corrosion defects in a rotor disk blade groove portion storing a turbine blade blade root portion using an ultrasonic flaw detection probe,
An ultrasonic flaw detection probe, and a support base for the ultrasonic flaw detection probe that slidably contacts the reference surface with the shoulder surface on the outer periphery of the rotor disk facing the rotor disk blade groove as a reference surface,
While maintaining the ultrasonic flaw detection probe in a position facing the rotor disk blade groove by moving the ultrasonic flaw detection probe in the circumferential direction on the outer peripheral surface of the rotor disk while the support base is in contact with the reference surface, the rotor disk It is configured to detect stress corrosion defects in blade grooves.

In the apparatus according to the present invention, it is preferable that a roller whose surface is in contact with the reference surface is provided on an ultrasonic flaw detection probe support table, and the support table is slidably contacted with the reference surface via the roller. This facilitates the movement of the support base and facilitates manual scanning.
Further, in addition to the above configuration, if the magnetic attraction force is applied to the roller, the support base can be stably brought into sliding contact with the reference surface.

  In addition, when there is a shroud connecting the outer end sides of a plurality of turbine blades, a locking member that is movable in the two-dimensional coordinate direction is provided on the ultrasonic flaw detection probe support base via a bracket, and the support base is attached to the shroud. The support base may be configured to be supported by the turbine rotor at two points by locking the locking member to at least one side surface of the shroud connecting the outer ends of the turbine blades while being in sliding contact with the reference surface. .

  Accordingly, the ultrasonic flaw detection probe support base can be supported by the shroud, and the support base can be positioned at a desired position by the shroud. Therefore, the positioning and movement of the support base are further facilitated.

Furthermore, in the apparatus of the present invention, it is preferable that the ultrasonic flaw detection probe is attached to the support base so as to be swingable in the inner surface of the rotor disk. As a result, the angle of the ultrasonic flaw detection probe within the circumferential surface of the rotor disk can be freely changed, so that an ultrasonic wave can be incident on the crack generated in the rotor disk blade groove part while changing the angle.
In a crack generated in the rotor disk blade groove, a reflected echo may not be generated for an ultrasonic wave irradiated from a certain direction. However, by adopting the above-described configuration, it becomes possible to generate a reflection echo with respect to a crack generated in an arbitrary direction, and it is possible to eliminate a detection omission of a defective portion.

  In addition, if the ultrasonic flaw detection probe is attached to the support base so as to be movable in the radial direction of the rotor disk, the ultrasonic wave reflected from the generated crack is detected at the position where the maximum string can be captured. A flaw detection probe can be arranged, thereby improving the detection accuracy of the defective portion.

  According to the method of the present invention, in a turbine rotor blade groove flaw detection method for detecting stress corrosion defects in a rotor disk blade groove portion containing a turbine blade blade root using an ultrasonic flaw detection probe, the rotor disk facing the rotor disk blade groove portion is provided. A support base that supports the ultrasonic flaw detection probe is brought into contact with the reference surface with the outer shoulder as a reference plane, and the ultrasonic flaw detection probe is rotated around the outer peripheral surface of the rotor disk while the support base is in contact with the reference plane. By moving in the direction, the ultrasonic flaw detection probe is held at a position facing the rotor disk blade groove part, and stress corrosion defects in the rotor disk blade groove part are detected, so that the shoulder existing on the outer peripheral surface of the rotor disk is detected. Because the ultrasonic flaw detection probe support is placed along the surface, the ultrasonic sound is not required without requiring a large positioning jig. Positioning a testing probe to the optimum position capable of capturing reflected echo is possible. Therefore, manual scanning of ultrasonic waves becomes easy, the time required for flaw detection can be shortened, the flaw detection apparatus can be simplified, and the cost can be reduced.

  In addition, according to the present invention apparatus, an ultrasonic flaw detection probe, and a support base for the ultrasonic flaw detection probe that slidably contacts the reference plane with the rotor disk outer peripheral shoulder facing the rotor disk blade groove as a reference plane, While maintaining the ultrasonic flaw detection probe in a position facing the rotor disk blade groove by moving the ultrasonic flaw detection probe in the circumferential direction on the outer peripheral surface of the rotor disk while the support base is in contact with the reference surface, the rotor disk Since it is configured to detect stress corrosion defects in the blade grooves, the method of the present invention can be implemented with a simple and low-cost apparatus. Therefore, manual scanning of ultrasonic flaw detection is facilitated, and the time required for flaw detection can be shortened.

  Further, unlike the ultrasonic flaw detector disclosed in Patent Document 1, no guide rail is required, and it is possible to cope with various rotor shapes and operability and versatility are improved, so that inspection efficiency can be improved.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the present invention to that only, unless otherwise specified.

(Embodiment 1)
1st Embodiment which concerns on the flaw detection apparatus of this invention is described based on FIGS. FIG. 1 shows part of a rotor of a high / medium pressure steam turbine in a power plant. In FIG. 1, a blade implantation groove 2 that opens outward is formed in the outer peripheral end of the rotor disk 1 over the entire circumference. A blade root portion 5 is integrally formed at a lower portion of the blade 4, and the blade root portion 5 of the blade 4 is fitted into the blade implantation groove 2, so that a large number of blades 4 extend over the entire outer periphery of the rotor disk 1. Planted.

  A shroud 6 is provided at the outer peripheral end of the blade 4 to connect the blades 4 every predetermined number. Further, the rotor disk 1 is formed with a shoulder portion 3 formed of an inclined surface formed over the entire circumferential direction of the rotor disk 1 at a position facing the blade implantation groove 2. The blade implantation groove 2 shown in FIG. 1 is T-shaped, but as shown in FIG. 2, a blade implantation groove 2 ′ having a double T shape is formed, and the blade root portion 5 is also formed in the blade implantation groove 2. It may be formed in a double T shape to match the shape of '.

  Since a rotor of a high / medium pressure steam turbine in a power plant is operated under a high temperature condition, stress corrosion cracking c occurs at a portion subjected to stress as shown in FIG. 1 when used for a long time. Sometimes.

  FIG. 3 is a perspective view showing the ultrasonic flaw detector 10 according to the present embodiment, and FIG. 4 is a front view of the same. 3 and 4, a long hole 11a is formed in the support base 11 in the longitudinal direction, and an ultrasonic flaw detection probe 12 is attached to the long hole 11a. As shown in FIG. 4, the ultrasonic flaw detection probe 12 is connected to a moving table 13 attached to the support table 11 via a spring structure 15. The moving table 13 is fastened and fixed to the support table 11 with screws 14, but the fixing position of the moving table 13 can be changed by loosening the screws 14, so the fixing position of the ultrasonic flaw detection probe 12 is Adjustment is possible in the direction of arrow b.

  In this way, the ultrasonic flaw detection probe 12 is disposed so as to be in close contact with the outer peripheral surface 1 a of the rotor disk 1, and is in close contact with the outer peripheral surface 1 a of the rotor disk 1 by the spring structure 15. It can swing in the direction of arrow d in the plane of 1a. Further, a support surface 11 b formed so as to abut on the shoulder portion (inclined surface) 3 is provided on the upper portion of the support base 11.

  In this embodiment having such a configuration, when the periphery of the blade implantation groove 2 of the rotor disk 1 is inspected, the operator picks up the support base 11 on which the ultrasonic flaw detection probe 12 is mounted, and the shoulder portion (inclined surface) 3. The support table 11 is positioned on the rotor disk 1 so that the support surface 11 b of the support table 11 is brought into contact with the rotor disk 1. In this state, the ultrasonic flaw detection probe 12 is in close contact with the outer peripheral surface 1 a of the rotor disk 1 and faces the radial direction of the rotor disk 1. Then, the defect detection of the blade implantation groove 2 is performed by the ultrasonic flaw detection probe 12 over the entire circumference of the rotor disk 1 while moving the support base 11 in the circumferential direction of the rotor disk 1 with the shoulder portion (inclined surface) 3 as a reference plane. To do.

  According to the present embodiment, since the shoulder portion (inclined surface) 3 of the rotor disk 1 is used as a reference surface, ultrasonic flaw detection is performed while the support surface 11b of the support base 11 is in sliding contact with the shoulder portion (inclined surface) 3. The size of the ultrasonic flaw detector 10 is not affected by the size of the rotor disk 1. Therefore, even if the diameter of the rotor disk 1 is increased, it is not necessary to increase the size of the ultrasonic flaw detector 10. Further, unlike the ultrasonic flaw detector disclosed in Patent Document 1, no guide rail is required. Therefore, the configuration of the ultrasonic flaw detector 10 can be simplified and the cost can be reduced.

  Further, since the ultrasonic flaw detection probe 12 is held at a position facing the blade implantation groove 2 by contacting the support surface 11b with the shoulder portion (inclined surface) 3, it is reflected from a defect portion around the blade implantation groove 2. This makes it easier to capture the ultrasonic waves. Furthermore, since the support base 11 is moved in a state where the support base 11 is placed on the shoulder portion (inclined surface) 3, workability is improved and inspection work can be made efficient.

Further, since the ultrasonic flaw detection probe 12 can be fixed so as to be movable in the longitudinal direction of the support base 11, it can be fixed at a position where the reflected echo from the stress corrosion crack c generated in the blade implantation groove 2 can be received to the maximum. Therefore, the flaw detection accuracy can be improved.
Further, since the shoulder portion (inclined surface) 3 is positioned as the reference surface, positioning becomes easy, the apparatus configuration can be simplified, and the cost can be reduced.

  It is unclear what the three-dimensional shape of the defect generated around the wing implantation groove 2 is. Therefore, an operation such as directing the ultrasonic flaw detection probe 12 at an angle is also required to some extent. In the present embodiment, the ultrasonic flaw detection probe 12 is basically directed in the radial direction of the rotor disk 1 in order to point the ultrasonic flaw detection probe 12 at an angle that can be detected best.

  In addition, since the ultrasonic flaw detection probe 12 is mounted so as to be swingable in the direction of the arrow d via the spring structure 15 and is swingable within the outer peripheral surface 1a of the rotor disk 1, the operator manually operates the ultrasonic wave. By performing the ultrasonic flaw detection while changing the angle of the flaw detection probe 12, it is possible to detect all the cracks c that cannot be detected with the ultrasonic flaw detection probe 12 left in the radial direction of the rotor disk 1.

  According to the present embodiment, for example, when performing ultrasonic flaw detection of a turbine rotor having a 10-stage rotor disk 1, conventionally, manual scanning by an operator required 3 to 4 days. It became possible to carry out in one day by applying.

(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to FIGS. 5 and 6, in the present embodiment, an example in which a suspending portion 20 configured so that the support pedestal 11 is locked to the shroud 6 and suspended from the shroud 6 is formed integrally with the upper portion of the support pedestal 11. is there. Other configurations are the same as those of the first embodiment.

  5 and 6, the suspending portion 20 is movable in the radial direction of the rotor disk 1 with respect to the column 21 formed integrally with the upper part of the support base 11 in the radial direction of the rotor disk 1 and the column 21. And a locking member 23 slidably fitted to the bracket 22 in the longitudinal direction of the bracket 22.

  The support column 21 has a quadrangular cross section, and rails 21 a are integrally disposed on both side surfaces of the support column 21 that engage with the bracket 22. On the other hand, the bracket 22 is provided with a recess (not shown) that is loosely fitted to the rail 21 a, and the bracket 22 is movable in the radial direction (arrow e direction) of the rotor disk 1 with respect to the column 21.

  Further, rails 22 a are integrally formed on both side surfaces of the bracket 22, and recesses (not shown) provided in the locking member 23 are loosely fitted to the rail 22 a, whereby the locking member 23 is attached to the bracket 22. It is slidable in the direction of arrow f on the tip side. The bracket 22 is fastened and fixed to the support column 21 with a screw 24 at a desired position. The locking member 23 is fastened and fixed to the bracket 22 by a screw 25 at a desired position.

  The locking member 23 is L-shaped in cross section, and the lower end is locked to one end surface 6 a of the shroud 6, whereby the support base 11 is suspended by the shroud 6.

In this embodiment having such a configuration, the position of the bracket 22 with respect to the support base 11 and the position of the locking member 23 with respect to the bracket 22 are adjusted according to the size of the blade 4. Then, when the support surface 11 b of the support base 11 is brought into contact with the shoulder portion (inclined surface) 3, the locking member 23 is disposed so as to be locked to the end surface 6 a of the shroud 6.
Thereby, as shown in FIG. 6, the support base 11 can be supported at two points by the shoulder portion (inclined surface) 3 and the end surface 6 a of the shroud 6. In this state, the support base 11 is moved in the circumferential direction of the rotor disk 1 on the outer peripheral surface 1 a of the rotor disk 1 to perform ultrasonic flaw detection around the blade implantation groove 2.

  According to the present embodiment, in addition to the operational effects obtained in the first embodiment, the following operational effects can be obtained. That is, since the support base 11 is supported at two points by the shroud 6 and the shoulder portion (inclined surface) 3, the worker mainly supports the support base 11 while placing the support surface 11 b of the support base 11 against the shoulder portion (inclined surface) 3. Therefore, the operation becomes easy and the positioning of the support base 11 can be further stabilized.

Moreover, since the fixing position of the bracket 22 and the locking member 23 of the hanging part 20 can be changed in accordance with the size of the blade 4, the blade 4 can be applied to various shapes or sizes.
Furthermore, since the size of the hanging portion 20 is changed by the rails 21a and 22a and is fixed by the screws 24 and 25, it can be simplified and reduced in cost.

  As described above, according to the present embodiment, the operability can be improved and various turbine rotor shapes can be coped with, so that the versatility can be improved, thereby further improving the efficiency of the inspection work. it can.

(Embodiment 3)
Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 7, in this embodiment, a roller 30 is interposed between the support surface 11 b of the support base 11 and the shoulder portion (inclined surface) 3 of the rotor disk 1. Other configurations are the same as those of the second embodiment. As shown in FIG. 7B, the roller 30 is rotatably mounted on the support surface 11b, and the tip 30a of the roller 30 is formed in an arcuate cross section (R shape) as shown. ing. Further, by using the roller 30 as a magnet, a magnetic attractive force is applied between the support surface 11 b and the shoulder portion (inclined surface) 3.

  According to the present embodiment, in addition to the second embodiment, by providing the support surface 11b with the roller 30, the support surface 11b of the support base 11 is lifted from the shoulder (inclined surface) 3, and the support surface 11b and the shoulder Since the portion (inclined surface) 3 is brought into contact with only the roller 30, the ultrasonic flaw detection probe 12 can be easily scanned. Further, since the magnetic force is applied between the support surface 11b and the shoulder portion (inclined surface) 3 using the roller 30 as a magnet, the support table 11 can be held more stably.

  Furthermore, since the cross section of the front end portion 30a of the roller 30 is rounded to have an arc shape, the support base 11 can be smoothly moved in the range where the inclination angle α of the shoulder portion (inclined surface) 3 is close to 0 to 90 °. Can be implemented.

  In the first to third embodiments, the shoulder 3 of the rotor disk 1 is an inclined surface. However, the present invention can be applied even if the shoulder 3 is a stepped portion that forms a horizontal direction.

  ADVANTAGE OF THE INVENTION According to this invention, a defect detection can be performed at low cost for a short time using the ultrasonic flaw detector of a simple structure for the blade groove part of a steam turbine rotor disk.

It is a perspective view of the blade implantation groove 2 of the rotor disk 1 to which the present invention is applied. It is a perspective view of another example of the blade implantation groove 2 of the rotor disk 1 to which the present invention is applied. 1 is a perspective view of an ultrasonic flaw detector 10 according to a first embodiment of the present invention. It is a front view of the ultrasonic flaw detector 10 which concerns on the said 1st Embodiment. It is a perspective view of ultrasonic testing equipment 10 concerning a 2nd embodiment of the present invention. It is a side view of the second embodiment. It is related with the ultrasonic flaw detector 10 which concerns on 3rd Embodiment of this invention, (a) is a side view, (b) is the partially expanded sectional view. It is a perspective view of the conventional steam turbine rotor. It is a perspective view of the conventional rotor disk. It is a front view of the conventional ultrasonic flaw detector. It is a side view of the conventional ultrasonic flaw detector.

Explanation of symbols

1 Turbine rotor disk 2 Rotor disk blade implantation groove 3 Shoulder (inclined surface)
4 Blade 5 Turbine Blade Blade Root 6 Shroud 6a Shroud End Surface 11 Support Base 11b Support Surface 12 Ultrasonic Flaw Detection Probe 13 Moving Base 14, 24, 25 Fixing Screw 15 Spring Structure 22 Bracket 23 Locking Member 30 Roller 30a Roller Tip

Claims (9)

In a turbine rotor blade groove flaw detection method for detecting stress corrosion defects in a rotor disk blade groove portion containing a turbine blade blade root using an ultrasonic flaw detection probe,
With the shoulder on the outer periphery of the rotor disk facing the rotor disk blade groove as a reference plane, a support base that supports the ultrasonic flaw detection probe is brought into contact with the reference plane,
While maintaining the ultrasonic flaw detection probe in a position facing the rotor disk blade groove by moving the ultrasonic flaw detection probe in the circumferential direction on the outer peripheral surface of the rotor disk while the support base is in contact with the reference surface, the rotor disk A method for flaw detection in a turbine rotor blade groove characterized by detecting a stress corrosion defect in the blade groove.   2. The turbine rotor blade according to claim 1, wherein the support base is slidably contacted with the reference plane using a magnetic attraction force applied between the support base and the reference plane. 3. How to detect the groove.   2. The turbine rotor according to claim 1, wherein the support base is moved while the support base is supported at two points by the reference surface and at least one side surface of the shroud connecting the outer end of the turbine blade. A method for flaw detection in the blade groove. In a turbine rotor blade groove flaw detection apparatus for detecting stress corrosion defects in a rotor disk blade groove portion storing a turbine blade blade root portion using an ultrasonic flaw detection probe,
An ultrasonic flaw detection probe, and a support base for the ultrasonic flaw detection probe that slidably contacts the reference surface with the shoulder surface on the outer periphery of the rotor disk facing the rotor disk blade groove as a reference surface,
While maintaining the ultrasonic flaw detection probe in a position facing the rotor disk blade groove by moving the ultrasonic flaw detection probe in the circumferential direction on the outer peripheral surface of the rotor disk while the support base is in contact with the reference surface, the rotor disk A flaw detector for a turbine rotor blade groove, characterized by detecting stress corrosion defects in the blade groove.   The turbine rotor blade groove part according to claim 4, wherein a roller whose roller surface is in contact with the reference surface is provided on the support table, and the support table is slidably contacted with the reference surface via the roller. Flaw detection equipment.   The flaw detection apparatus for a turbine rotor blade groove part according to claim 5, wherein a magnetic attraction force is applied to the roller. A locking member that is relatively movable in a two-dimensional coordinate direction is provided on the support base via a bracket, and the locking member is connected to the outer end of the turbine blade in a state where the support base is in sliding contact with the reference plane. By locking on at least one side of the shroud,
The flaw detection apparatus for a turbine rotor blade groove part according to claim 4, wherein the support base is configured to be supported by the turbine rotor at two points.   The turbine rotor blade groove flaw detection apparatus according to claim 4, wherein an ultrasonic flaw detection probe is attached to the support base so as to be swingable in an inner circumferential surface of the rotor disk.   The turbine rotor blade groove part flaw detection apparatus according to claim 4, wherein an ultrasonic flaw detection probe is attached to the support base so as to be movable in a radial direction of the rotor disk.

Images