JPH0581711U - Brittleness measuring device - Google Patents

Abstract

(57) [Abstract] [Purpose] When measuring the embrittlement of a specimen, it is automated to enhance the measurement data. [Structure] A drive shaft that moves back and forth in a center hole formed in a rotary shaft, and has a drive operation unit at one end of the drive shaft, and a removable polishing unit and an etching unit at the other end. At least one or more of the measurement center units including the cleaning unit, the cleaning unit, and the transfer unit are provided, and the control unit controls the advance / retreat of the measurement center units.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to, for example, an improvement of an embrittlement measuring device for measuring the degree of embrittlement of a rotating shaft from the inner surface of a central hole formed in the center of the rotating shaft.

[0002]

[Prior Art]

 For example, a rotating shaft (turbine rotor) used in a steam turbine or the like is subject to a change in its material structure because it is constantly exposed to ultra-high temperature and ultra-high pressure steam, and its material is likely to deteriorate. The so-called temper embrittlement is a particular problem in material deterioration.

Tempering embrittlement is that impurity elements such as P, Sn, As, and Sb contained in the rotating shaft segregate at the crystal grain boundaries to weaken the grain boundary strength. Tempering embrittlement causes fracture toughness, and there is a risk of causing material destruction starting from small defects. Therefore, from the viewpoint of preventing accidents, various techniques have been proposed for measuring the degree of embrittlement of rotating shafts caused over time.

A Charpy impact test is one of the widely known techniques for measuring the embrittlement of a rotating shaft. In this test, the degree of decrease in the absorbed energy value when the test piece is destroyed by impact, or the shift of the data in the master curve due to the impact value-temperature to the high temperature side, that is, the amount of increase in the transition temperature of the impact value, or the impact The ratio of the ductile fracture surface area of the fracture surface of the fractured test piece to the total fracture surface area was measured, and the ductile fracture surface ratio was calculated based on this ratio. The degree of embrittlement is evaluated by the amount of increase in the fracture surface transition temperature FATT (ΔFATT) defined at a temperature corresponding to a ductile fracture surface ratio of 50%.

However, in this test, the test piece has to be taken out from the actual machine, and considering the restoration of the taken out site after the test, it is not realistic at all even at the laboratory level.

Therefore, as a technique for measuring the degree of embrittlement of a rotating shaft without removing the test piece from the actual machine, the publication of Japanese Patent Laid-Open No. 1-110259 is being considered. As shown in FIG. 7, this technique only brings the cell 33 into contact with the subject 34, and the surface of the subject 34 is etched by the intergranular corrosive liquid 36 absorbed by the hygroscopic material 35 in the cell 33. After etching, the grain boundaries of the sample are corroded, and subsequently the corrugated corrugation of the corroded corrosive grooves is transferred by a replica film, etc., and the data of the intergranular corrosion groove depth after transfer is created in advance. Then, it is plotted on a master curve (this master curve is the relationship between intergranular corrosion groove depth and embrittlement obtained in advance by experiments), and the degree of embrittlement progress of the material is known by plotting. ..

[0007]

[Problems to be solved by the device]

 However, in such a technique, it is somewhat impossible to apply it to the central hole formed in the steam turbine shaft for the following reason.

Generally, a central hole is bored in a steam turbine shaft because many impurity elements such as P, Sn, As and Sb are contained in the shaft, and these impurity elements are formed in the central portion of the shaft during rotation of the shaft. This is because they gather and cause deterioration of the material. Therefore, a hole with a diameter of about 10 mm is preliminarily formed in the center of the shaft so that the above-mentioned impurity element does not collect in the center of the shaft.

Against this background, it is impossible to apply the above-mentioned technique to the axial center hole due to its size. In addition, this kind of rotating shaft has a diameter of 1 m or more, and the temperature transmission is different between the surface of the shaft diameter and the surface of the central hole, and the susceptibility to temper embrittlement is naturally different. Brittle fracture occurs at the center of the shaft where the stress is the most severe, and if the susceptibility to temper embrittlement is different, I feel a little anxiety about the reliability of the measured data itself. Furthermore, with the above-mentioned technique, since the intergranular corrosive liquid is impregnated into the absorber, there is a problem in that there is a bias in the density, making it difficult to obtain accurate measurement data for intergranular corrosion.

In view of the current problems, the present invention discloses a brittleness measuring device that automates each measuring unit so that accurate data can be obtained regardless of the size and shape of the device. The purpose is to do.

[0011]

[Means for Solving the Problems]

 The embrittlement measuring device according to the present invention has first to sixth configurations. First configuration;

A drive shaft that moves back and forth in a central hole formed in the rotary shaft, and has a drive operation part at one end of the drive shaft, and a removable and replaceable polishing part at the other end. It is characterized in that at least one or more of the measurement central units including the etching unit, the cleaning unit, and the transfer unit are provided, and the control unit controls the advance / retreat of the measurement central units. Second configuration;

The polishing unit of the measurement center unit is characterized in that a motor for driving a polishing wheel and a camera for projecting a polishing region of a subject through a prism are integrally incorporated. Third configuration;

In the etching unit of the measurement center unit, a cell and a liquid tank are integrally incorporated, and a pump is interposed between the cell and the liquid tank to circulate a liquid that corrodes the surface of the subject. It is characterized in that a packing is attached to the cell contacting portion of the cell, and a cylinder portion is provided so that the cell can move back and forth with respect to the cell. Fourth configuration: The packing is provided with an exhaust passage. Fifth configuration: The liquid tank is characterized in that a heating element is additionally provided. Sixth configuration;

Of the measurement center unit, the cleaning unit, the transfer unit, and the etching unit are connected to each other so that they can be fitted together, while the cleaning unit incorporates a motor for driving the cleaning wheel and a cleaning liquid tank as a unit. The transfer section is equipped with a camera that takes a picture of a grain boundary corrosion groove generated by a corrosive liquid applied to the subject from the etching section and projected by a replica through a prism.

[0016]

[Action]

 In the above configuration, in the embrittlement measurement of the subject, first, the polishing section is positioned at the measurement site, and the motor is driven to polish the site by the polishing wheel. The polishing status is stored in the camera through the prism.

When the polishing is completed, an etching unit is attached to the drive shaft, and the drive shaft is moved to a measurement position by an instruction of the drive operation unit. Here, the cell is brought into contact with the test object by driving the cylinder unit. A liquid is supplied from the cell to the specimen, which corrodes the grain boundaries of the crystal structure of the specimen. During this corrosion, the liquid is circulated between the cell and the liquid tank by the pump and heated.

When the intergranular corrosion groove is created in the subject, the cleaning unit and the transfer unit are also attached to the drive shaft, and the motor of the cleaning unit rotates the cleaning wheel under the command of the drive operation unit to clean the cleaning liquid. The residual liquid of the sample is removed by the cleaning liquid from the bath. Subsequently, the intergranular corrosion groove of the object is imaged by the replica of the transfer part, and the image is imaged on the camera through the prism.

As described above, in the embrittlement measuring device according to the present invention, even if the measurement position of the object is difficult to measure, polishing of the object, generation of corrosion of grain boundaries, cleaning, and images of intergranular corrosion can be performed. Since a series of work steps for production can be continuously and automatically operated, brittleness measurement data with less error measurement can be obtained.

[0020]

【Example】

 An embodiment of an embrittlement measuring device according to the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is a subject, for example, a turbine rotor, and a central portion of the turbine rotor 1 is provided with a central hole 2 along its axis.

The center hole 2 has a drive operating portion 5 at one end thereof so that the drive shaft 4 can move back and forth. Further, the other end of the drive shaft 4 is provided with a measuring central part 3 including a polishing part 3a which can be detached and exchanged, an etching part 3b, a cleaning part 3c, and a transfer part 3d.

A control unit 6 is connected to the measurement central unit 3 via a lead wire, and the measurement central unit 3 is operated by a command from the control unit 6. The behavior of the measurement central unit 3 is displayed on the television monitor 7. By the way, in measuring the embrittlement of the subject 2a using the center hole 2 as an example, first, as shown in FIG. 2, polishing of the subject 2a is started.

In this case, the polishing portion 3 a is attached to the drive shaft 4. The polishing unit 3a is a combination of a motor 8 for rotating the polishing oil 9 and a camera (CCD camera) 10 for recording through the prism 20a after polishing the subject 3a. After that, it can be separated from the drive rod 4. After the polishing of the object 2a is completed, the etching of the object 2a is started. The etching part 3b is attached to the drive shaft 4, and the etching part 3b is moved to the measurement site of the subject 2a according to a command from the driving operation part 5.

As shown in FIG. 3, the etching section 3 b has a cell 11 and a liquid tank 12, and they are connected to each other via a pump 28. Further, the cell 11 can be moved up and down by the cylinder portion 21. These are integrally incorporated as the etching portion 3b. The etching part 3b will be described in a little more detail with reference to FIG.

In the figure, reference numeral 11 indicates a cell, and reference numeral 12 indicates a liquid tank. The cell 11 and the liquid tank 12 are connected to each other through a pump 28 and a valve 31 through a forward path 29 and a return path 30, whereby the liquid 27 is circulated between the cell 11 and the liquid tank 12. There is. A heater 26 is attached to the liquid tank 12, and the liquid 27 is heated by the heater 26.

On the other hand, a packing 24 is attached to the bottom of the cell 11, and the packing 24 is provided with a suction port 25 for drawing out the air stagnated by the subject 2a. Further, a cylinder portion 21 that can move the cell 11 up and down is provided on the side portion of the cell 11, and the force of the cylinder portion 21 adjusts the degree of contact with the subject 2a of the cell 11.

When the etching part 3b is arranged at the position of the measuring part of the test object 2a, the liquid 27 from the cell 11 is applied to the test object 2a, which causes intergranular corrosion between the crystal structures of the test object 2a. To be done. Thus, when the intergranular corrosion of the subject 2a is generated, the drive shaft 4 is attached with the cleaning unit 3c and the transfer unit 3d shown in FIG. 4 at the tip of the etching unit 3b.

FIG. 4 is a schematic view in which the cleaning unit 3c and the transfer unit 3d are attached to the drive shaft 4, and the cleaning unit 3c has a motor 15 for rotating the cleaning wheel 16 and a cleaning liquid tank 17 integrated therein. Therefore, the residual corrosive liquid of the object 2a is supplied to the residual liquid through the cleaning wheel 16 of the cleaning liquid discharged from the cleaning liquid tank 17, thus removing the residual corrosive liquid.

When the intergranular corrosion groove is formed in the crystal grain boundary of the test object 2a by the corrosive liquid, the transfer portion 3d is moved to the corresponding portion by the drive shaft 4, and here the intergranular corrosion groove is imaged by the replica 10a. The image is recorded on the camera (CCD camera) 10 through the prism 20b.

When the intergranular corrosion groove of the subject 2a is recorded in this manner, the data is obtained by comparing the previously created master curve of FIG. 6, that is, the embrittlement degree ΔFATT and the intergranular corrosion groove depth d. The relationship is plotted on a characteristic graph, the embrittlement degree line H is drawn with the plot, and the embrittlement degree of the subject is evaluated from the embrittlement degree line H.

The embrittlement of the subject 2a evaluated in this way is not always accurate due to the addition of a manual element, and the measurement is all automated as compared with the conventional method which was only a standard evaluation. The reliability of data can be further increased.

[0032]

[Effect of the device]

 As is clear from the above description, in the embrittlement measuring device according to the present invention, polishing, etching, cleaning, and transfer of the sample are all automated, so it is more reliable than the conventional embrittlement measurement. Furthermore, it is possible to achieve industrially excellent effects such as faster measurement speed.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a brittleness measuring device according to the present invention.

FIG. 2 is a conceptual diagram in which a polishing portion is attached to a center hole of a turbine rotor that is an example of a subject.

FIG. 3 is a conceptual diagram in which an etching portion is attached to a center hole of a turbine rotor that is an example of a subject.

FIG. 4 is a conceptual diagram in which a cleaning unit, a transfer unit, and an etching unit are attached to a central hole of a turbine rotor that is an example of a subject.

FIG. 5 is an enlarged conceptual diagram showing a structure of an etching part.

FIG. 6 is a graph showing the relationship between the intergranular corrosion groove depth and the degree of embrittlement of a test object.

FIG. 7 is a conceptual diagram showing a conventional embrittlement measuring device.

[Explanation of symbols]

 1 Turbine rotor 2 Center hole 2a Subject 3 Measuring central part 3a Polishing part 3b Etching part 3c Cleaning part 3d Transfer part 4 Drive shaft 5 Drive operating part 7 Control part 8,15 Motor 9 Polishing wheel 10 Camera 10a Replica 11 Cell 12 Liquid tank 16 Cleaning wheel 17 Cleaning liquid tank 21 Cylinder part 24 Packing 25 Exhaust passage 26 Heating element 28 Pump

Claims (6)

[Scope of utility model registration request] 1. A drive shaft that moves back and forth in a center hole formed in a rotary shaft, wherein a drive operating portion is provided at one end of the drive shaft, and the other end of the drive shaft is removable and replaceable. An embrittlement measuring apparatus, comprising at least one of a measuring central part including an etching part, an etching part, a cleaning part, and a transferring part, and controlling the advance / retreat of the measuring central part by a control part. 2. The embrittlement measuring device, wherein the polishing unit of the measurement center unit integrally incorporates a motor for driving a polishing wheel and a camera for projecting a polished portion of a subject through a prism. .. 3. A cell and a liquid tank are integrally incorporated in the etching unit of the measurement central unit, and a pump is interposed between the cell and the liquid tank to circulate a liquid that corrodes the surface of the subject. On the other hand, the embrittlement measuring device is characterized in that a packing is attached to a subject contact portion of the cell and a cylinder portion is provided so that the cell can move back and forth with respect to the subject. 4. The embrittlement measuring device according to claim 3, wherein the packing is provided with an exhaust passage. 5. The embrittlement measuring device according to claim 4, wherein a heating element is attached to the liquid tank. 6. A cleaning unit, a transfer unit, and an etching unit of the measurement central unit are connected to each other so that they can be fitted to each other, while a motor for driving a cleaning wheel and a cleaning liquid tank are integrally incorporated in the cleaning unit. At the same time, the transfer unit is provided with a camera that images the image of the intergranular corrosion grooves generated by the corrosive liquid given to the subject from the etching unit by the replica, through the prism. ..