Metal fatigue evaluation device, method and program

Abstract

To provide a metal fatigue evaluation device capable of evaluating more properly evaluating a degree of metal fatigue, a metal fatigue evaluation method, and a metal fatigue evaluation program.SOLUTION: A disclosed metal fatigue evaluation device D is a device for finding an evaluation index representing a degree of metal fatigue in an evaluation object. The metal fatigue evaluation device includes: a data acquisition unit 1 that acquires diffraction ring data representing the formed diffraction ring by illuminating the object with a beam that has a diffracting property; and an index processing unit 22 that calculates a uniformity index that represents a degree of uniformity of peak intensity in the diffraction ring as the evaluation index on the basis of, the diffraction ring data acquired by the data acquisition unit 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a metal fatigue evaluation device, a metal fatigue evaluation method, and a metal fatigue evaluation program for evaluating the degree of metal fatigue using a diffraction ring. [Background technology]

[0002] Damage to equipment due to metal fatigue may lead to abrupt process stoppage, accidents, etc., so it is important and desirable to evaluate the degree of metal fatigue. A technique for evaluating the degree of metal fatigue is disclosed in, for example, Patent Document 1.

[0003] In this patent document, X-ray diffraction is performed on fatigued areas identified by observation of corroded areas due to structural change to martensite, and the change in half-width of martensite and the change in retained austenite are measured, and the degree of fatigue is calculated from the measurement results.

[0004] Generally, when the periodicity of a crystal is high, strong diffracted waves (Bragg reflected waves) are generated in a direction defined by the periodic interval and periodic direction. On the other hand, metal fatigue generates dislocations in the metal crystal, disrupting the periodicity of the metal crystal lattice. This causes the Bragg reflected waves to spread in the reflection direction, resulting in a change in the half-width of the diffracted waves (spread from the peak position). Therefore, it is presumed that the degree of metal fatigue can be evaluated by evaluating the half-width of the diffracted waves due to Bragg reflection at the crystal lattice, as in Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-41993 A Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, X-ray diffraction was performed on each sample with fatigue damage of 0[%], 10[%], 30[%], 50[%], and 100[%] by CrKα X-rays at an incident angle of 0 degrees, and the half-width of each diffraction ring was measured. As a result, the half-width of each diffraction ring was almost constant from the damage degree of 0[%] to 100[%]. This was considered to be due to the presence of a processing damage layer on the surface of each sample. For this reason, in order to expose the crystal of the base material, samples were created in which the processing damage layer on the surface was removed by electrolytic polishing (EP), and the half-width of the diffraction ring was measured in the same way. As a result, it was confirmed that the half-width increased with the increase in the damage degree from 0[%] to 100[%]. Therefore, it was confirmed that the half-width of the diffraction ring contains information on fatigue damage.

[0007] However, the amount of change was approximately 11% from the initial value (half width at a damage level of 0%) to the final value (half width at a damage level of 100%). It is presumed that the electrolytic polishing process was able to capture the change in half width due to fatigue damage, but in a situation where measurement errors due to the measurement location are also expected, a change of approximately 11% cannot be said to be a significant difference that allows for accurate identification of the degree of fatigue damage, and there is room for improvement in the evaluation method for evaluating the degree of metal fatigue using X-ray diffraction.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a metal fatigue evaluation device, a metal fatigue evaluation method, and a metal fatigue evaluation program that can more appropriately evaluate the degree of metal fatigue. [Means for solving the problem]

[0009] The inventors of the present invention have conducted various studies and found that the above object can be achieved by the present invention described below. That is, a metal fatigue evaluation device according to one aspect of the present invention is a device for obtaining an evaluation index representing the degree of metal fatigue in a metal evaluation object, and the device includes a diffraction ring formed by irradiating the evaluation object with a beam having a diffracting property. wholea data acquisition unit for acquiring diffraction ring data representing the diffraction ring represented by the diffraction ring data acquired by the data acquisition unit; whole and an index processing unit that determines, as the evaluation index, a uniformity index that represents the degree of uniformity of peak intensities in the region. Preferably, in the above-mentioned metal fatigue evaluation device, the data acquisition unit is an interface circuit that inputs and outputs data to and from an external device, and the external device is a storage medium that stores the diffraction ring data. Preferably, in the above-mentioned metal fatigue evaluation device, the data acquisition unit is an interface circuit that inputs and outputs data to and from an external device, and the external device is a drive device that reads data from a storage medium that stores the diffraction ring data. Preferably, in the above-mentioned metal fatigue evaluation device, the data acquisition unit is a communication interface circuit that transmits and receives communication signals to and from an external device, and the external device is a server device that is connected to the communication interface circuit via a network and manages the diffraction ring data.

[0010] When the metal to be evaluated is in an initial state, the number of crystal grains in the X-ray irradiated area is insufficient, so the diffraction ring has a spotty shape, but as metal fatigue progresses, the number of crystal grains increases due to the refinement of crystal grains (cell organization) accompanying dislocation proliferation, and it is believed that the diffraction ring becomes uniform. In fact, as metal fatigue progresses, as described below, the diffraction ring becomes uniform. The metal fatigue evaluation device obtains a uniformity index that represents the degree of uniformity of peak intensity in the diffraction ring based on the diffraction ring data as an evaluation index that represents the degree of metal fatigue, so that the degree of metal fatigue can be evaluated more appropriately.

[0011] In another aspect, in the metal fatigue evaluation device, finger The alignment processor determines the standard deviation in the intensity distribution of the diffraction ring with respect to the azimuth angle as the uniformity index.

[0012] This makes it possible to provide a metal fatigue evaluation device that determines the standard deviation in the intensity distribution of the diffraction ring with respect to the azimuth angle as the uniformity index, i.e., the evaluation index.

[0013] In another aspect, in the above-mentioned metal fatigue evaluation device, the data acquisition unit includes an irradiation unit that irradiates the beam, and a diffraction ring formed by irradiating the evaluation object with the beam by the irradiation unit. whole The diffraction ring whole and an imaging unit that generates diffraction ring data representing the diffraction ring. Preferably, in the metal fatigue evaluation device, the imaging unit includes an imaging plate.

[0014] Such a metal fatigue evaluation device generates and acquires diffraction ring data by the data acquisition unit, so that metal fatigue can be evaluated at the site of the evaluation target.

[0015] A metal fatigue evaluation method according to another aspect of the present invention is a method for obtaining an evaluation index that represents a degree of metal fatigue in a metal evaluation object, the method comprising: irradiating the evaluation object with a beam having a diffractive property to form a diffraction ring; whole a data acquisition step of acquiring diffraction ring data representing the diffraction ring; whole and an index processing step of determining, as the evaluation index, a uniformity index that indicates the degree of uniformity of peak intensity in the sample.

[0016] A metal fatigue evaluation program according to another aspect of the present invention is a program for obtaining an evaluation index that represents a degree of metal fatigue in a metal evaluation object, the program including causing a computer to display a diffraction ring formed by irradiating the evaluation object with a beam having a diffractive property. whole a data acquisition step of acquiring diffraction ring data representing the diffraction ring; whole and an index processing step of obtaining, as the evaluation index, a uniformity index that indicates the degree of uniformity of peak intensity in the sample.

[0017] Such metal fatigue evaluation method and metal fatigue evaluation program calculate a uniformity index indicating the degree of uniformity of peak intensity in the diffraction ring based on diffraction ring data as an evaluation index indicating the degree of metal fatigue, thereby enabling a more appropriate evaluation of the degree of metal fatigue. Effect of the Invention

[0018] The metal fatigue evaluation device, the metal fatigue evaluation method, and the metal fatigue evaluation program according to the present invention can more appropriately evaluate the degree of metal fatigue. [Brief description of the drawings]

[0019] [Figure 1] 1 is a block diagram showing a configuration of a metal fatigue evaluation device in an embodiment. [Diagram 2] FIG. 2 is a block diagram showing a configuration of an example of a data acquisition unit in the metal fatigue evaluation device. [Diagram 3] 10 is a diagram for explaining the state of change in the diffraction ring accompanying the progression of metal fatigue. FIG. [Figure 4] FIG. 2 shows, as an example, a diffraction ring, the intensity distribution of said diffraction ring versus azimuthal angle, its mean value and its standard deviation. [Diagram 5] 4 is a flowchart showing an operation of the metal fatigue evaluation device. [Figure 6] FIG. 1 is a diagram for explaining, as an example, the relationship between the degree of metal fatigue and the standard deviation of the strength distribution. [Figure 7] FIG. 13 is a diagram for explaining the relationship between the degree of metal fatigue and the half-value width of a diffraction ring, as an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments. In addition, configurations with the same reference numerals in each drawing indicate that they are the same configurations, and their description will be omitted as appropriate. In this specification, when referring to a general term, a reference numeral without a subscript is used, and when referring to an individual configuration, a reference numeral with a subscript is used.

[0021] The metal fatigue evaluation device in the embodiment is a device for obtaining an evaluation index representing the degree of metal fatigue in a metal evaluation object. The metal fatigue evaluation device includes a data acquisition unit that obtains diffraction ring data representing a diffraction ring formed by irradiating the evaluation object with a beam having a diffracting property, and an index processing unit that obtains, as the evaluation index, a uniformity index representing the degree of uniformity of peak intensity in the diffraction ring based on the diffraction ring data obtained by the data acquisition unit. Such a metal fatigue evaluation device will be described in more detail below.

[0022] Fig. 1 is a block diagram showing the configuration of a metal fatigue evaluation device in an embodiment. Fig. 2 is a block diagram showing the configuration of an example of a data acquisition unit in the metal fatigue evaluation device. Fig. 3 is a diagram for explaining the state of change in a diffraction ring with the progression of metal fatigue. Fig. 4 is a diagram showing, as an example, a diffraction ring, an intensity distribution with respect to the azimuth angle of the diffraction ring, its average value, and its standard deviation.

[0023] A metal fatigue evaluation device D in the embodiment includes a data acquisition unit 1, a control processing unit 2, a storage unit 3, an input unit 4, an output unit 5, and an interface unit (IF unit) 6, as shown in FIG.

[0024] The data acquisition unit 1 is connected to the control processing unit 2, and is a device that acquires diffraction ring data representing a diffraction ring formed by irradiating a metal (including alloy) evaluation target with a beam having a diffracting property according to the control of the control processing unit 2. The data acquisition unit 1 is, for example, an interface circuit that inputs and outputs data between an external device, and the external device is a storage medium such as a USB (Universal Serial Bus) memory and an SD card (registered trademark) that stores the diffraction ring data. Alternatively, for example, the data acquisition unit 1 is an interface circuit that inputs and outputs data between an external device, and the external device is a drive device that reads data from a storage medium such as a CD-ROM (Compact Disc Read Only Memory), a CD-R (Compact Disc Recordable), a DVD-ROM (Digital Versatile Disc Read Only Memory), and a DVD-R (Digital Versatile Disc Recordable) that records the diffraction ring data. Alternatively, for example, the data acquisition unit 1 may be a communication interface circuit that transmits and receives communication signals to and from an external device, and the external device may be a server device that is connected to the communication interface circuit via a network (WAN (Wide Area Network, including a public communication network)) or LAN (Local Area Network) and manages the diffraction ring data. When the data acquisition unit 1 is an interface circuit or a communication interface circuit, the data acquisition unit 1 may also serve as the IF unit 6 (i.e., the IF unit 6 may be used as the data acquisition unit 1).

[0025] In this embodiment, the data acquisition unit 1 includes an irradiation unit that irradiates the beam, and an imaging unit that images a diffraction ring formed by irradiating the evaluation object with the beam by the irradiation unit, and generates diffraction ring data representing the diffraction ring.

[0026] More specifically, the data acquisition unit 1 includes a high-voltage power supply 11, a cooling unit 12, a control unit 13, an X-ray irradiation unit 14, and an imaging unit 15, as shown in FIG.

[0027] The high-voltage power supply 11 is a device that supplies a high voltage for accelerating the electron beam to the X-ray irradiation unit 14. The cooling unit 12 is a device that cools the X-ray irradiation unit 14. The control unit 13 is a device that controls the operation of the entire data acquisition unit 1. The control unit 13 may also be used as a control unit 21, which is functionally configured in the control processing unit 2 and will be described later.

[0028] The X-ray irradiation unit 14 includes an X-ray generator that generates X-rays by colliding an electron beam with a target, and an X-ray irradiation tube that irradiates the generated X-rays as a thin X-ray beam to the evaluation object Ob. The X-ray generator is, for example, an X-ray tube (vacuum tube) that accelerates an electron beam with a high voltage and causes it to collide with an anode to generate CrKα characteristic X-rays. The X-ray irradiation tube is, for example, a pinhole collimator that narrows the generated X-rays into a thin parallel beam for irradiation.

[0029] The angle (irradiation angle) between the surface of the evaluation object Ob and the X-ray beam can be set in the range of more than 0° and less than 180°, but for example, 30° to 45° (or -30° to -45°) is preferable. An irradiation angle of 90° has a special meaning and is suitable for determining the so-called shear stresses τxz and τyz. An irradiation angle of -30° to -45° is suitable for determining the so-called stress σz.

[0030] The diameter of the irradiated X-ray beam may be smaller than 1 to 2 mm, for example, may be smaller than several hundreds of μm.

[0031] Note that, here, an example will be described in which X-rays are used as a beam (diffracted light) that has the property of diffracting toward the evaluation object Ob; however, beams that have the property of diffraction are not limited to X-rays, but also include electromagnetic waves (including visible light, ultraviolet rays, and gamma rays), neutron beams, electron beams, etc.

[0032] The imaging unit 15 is a device that images a diffraction ring formed by irradiating the evaluation object Ob with a beam by the X-ray irradiation unit 14, and generates diffraction ring data representing the diffraction ring. The imaging unit 15 is configured, for example, with a so-called imaging plate. This imaging plate utilizes the phenomenon of photostimulable fluorescence. In general, a film coated with a photostimulable phosphor is exposed to X-rays, and the amount of fluorescence generated by irradiating the exposed film with laser light is measured. The fluorescence emits light with an amount of light corresponding to the amount of exposure to X-rays, so an X-ray image can be obtained by measuring the amount of light emission.

[0033] Returning to Fig. 1, the input unit 4 is connected to the control processing unit 2 and is a device for inputting various commands, such as a command to start evaluation, and various data required for operating the metal fatigue evaluation device D, such as the name of an evaluation target to be evaluated by the metal fatigue evaluation device D (e.g., serial number, etc.), to the metal fatigue evaluation device D, and is, for example, a plurality of input switches, a keyboard, a mouse, etc., to which predetermined functions are assigned. The output unit 5 is connected to the control processing unit 2 and is a device for outputting commands and data input from the input unit 4, diffraction rings represented by the diffraction ring data acquired by the data acquisition unit 1, evaluation indices determined by the metal fatigue evaluation device D, etc., under the control of the control processing unit 2, and is, for example, a display device such as a CRT display, an LCD (liquid crystal display device), or an organic EL display, or a printing device such as a printer.

[0034] The IF unit 6 is connected to the control processing unit 2 and is a circuit that inputs and outputs data to and from, for example, an external device under the control of the control processing unit 2, such as an interface circuit for RS-232C, which is a serial communication method, an interface circuit using the Bluetooth (registered trademark) standard, and an interface circuit using the USB standard. The IF unit 6 may also be a communication interface circuit that transmits and receives communication signals to and from an external device, such as a data communication card or a communication interface circuit conforming to the IEEE802.11 standard.

[0035] The storage unit 3 is connected to the control processing unit 2 and is a circuit that stores various predetermined programs and various predetermined data under the control of the control processing unit 2. The various predetermined programs include, for example, a control processing program, which includes a control program that controls each of the units 1, 3 to 6 of the metal fatigue evaluation device D according to the function of each unit, and an index processing program that obtains a uniformity index that indicates the degree of uniformity of peak intensity in the diffraction ring as an evaluation index based on the diffraction ring data acquired by the data acquisition unit 1. The various predetermined data include data required to execute each of these programs, such as the diffraction ring data. The storage unit 3 includes, for example, a ROM (Read Only Memory) that is a nonvolatile storage element and an EEPROM (Electrically Erasable Programmable Read Only Memory) that is a rewritable nonvolatile storage element. The storage unit 3 includes a RAM (Random Access Memory) that serves as a so-called working memory of the control processing unit 2 that stores data generated during the execution of the predetermined programs. The storage unit 3 may include a hard disk device that can store a large capacity in order to store learning data that is relatively large in capacity.

[0036] The control processing unit 2 is a circuit for controlling each of the units 1, 3 to 6 of the metal fatigue evaluation device D in accordance with the function of each unit, and for determining an evaluation index that represents the degree of metal fatigue in the evaluation target. The control processing unit 2 is configured to include, for example, a CPU (Central Processing Unit) and its peripheral circuits. In the control processing unit 2, a control unit 21 and an index processing unit 22 are functionally configured by executing the control processing program.

[0037] The control unit 21 controls each of the units 1, 3 to 6 of the metal fatigue evaluation device D in accordance with the function of each unit, and is responsible for controlling the metal fatigue evaluation device D as a whole.

[0038] The index processing unit 22 determines, as an evaluation index, a uniformity index that indicates the degree of uniformity of the peak intensity in the diffraction ring based on the diffraction ring data acquired by the data acquisition unit 1.

[0039] FIG. 3 shows, as an example, the change in the diffraction ring with the progression of metal fatigue. FIG. 3 shows the diffraction ring images obtained by performing X-ray diffraction with CrKα X-rays incident at an incident angle of 0 degrees on each sample that was given fatigue damage of 0[%], 10[%], 30[%], 50[%], and 100[%] by tensile testing. A fatigue testing machine with a normal vibration load was used for the tensile test, and the number of cycles at the time of breakage was set as the damage degree of 100[%], and the damage degrees of 0[%], 10[%], 30[%], and 50[%] are the ratios of the number of cycles to this. As an example, the sample is a steel pipe material of a general standard used for boiler pipes. The upper row of FIG. 3 shows the diffraction ring images of each sample that was not subjected to electrolytic polishing, and the lower row shows the diffraction ring images of each sample that was subjected to electrolytic polishing. From left to right, the diffraction ring images are of samples with damage levels of 0[%], 10[%], 30[%], 50[%], and 100[%] in plan view.

[0040] 3 from left to right, it can be seen that the diffraction rings change from an initial spotty shape in which the peak intensity varies at each circumferential position to a shape in which the peak intensity becomes approximately uniform at each circumferential position as metal fatigue increases. Comparing this change with the results of TEM (transmission electron microscope) observations (not shown), it is inferred that the process in which a large number of fine cellular structures are formed by dislocation proliferation due to the accumulation of fatigue damage is related to the change in the diffraction rings to be uniform.

[0041] In general, when there are a sufficient number of crystal grains in the X-ray irradiation area, a uniform diffraction ring is obtained. The results shown in Figure 3 are inferred to be due to the fact that the number of crystal grains in the X-ray irradiation area was insufficient in the initial state, resulting in a spotty diffraction ring shape, but the number of crystal grains increased due to the refinement of the crystal grains (cell organization) associated with dislocation proliferation, which contributed to the uniformity of the diffraction ring. In evaluation methods using X-ray diffraction, including residual stress measurement, it is recommended that the average crystal grain size of the sample be 30 [μm] or less to avoid a decrease in measurement accuracy. Compared to this guideline, the ferrite grain size in the initial state of the sample in Figure 3 is about 50 to 60 [μm] at the largest, which is in the coarse category in terms of X-ray diffraction measurement, and is consistent with the above consideration.

[0042] From the above, it can be concluded that the phenomenon of the uniformity of diffraction rings due to the accumulation of fatigue damage is due to two factors: first, microstructural refinement due to dislocation multiplication (cell structure formation), and second, a change in the orientation of the microstructural structure.The unevenness of the diffraction ring is considered to be a physical quantity that succinctly represents the change in the microstructural structure, and the uniformity index, which indicates the degree of uniformity of the peak intensity in the diffraction ring, can be used as a new evaluation index to represent the degree of metal fatigue.

[0043] The uniformity index (=evaluation index) may be, for example, the difference between the maximum peak intensity and the minimum peak intensity with respect to the azimuth angle of the diffraction ring, the change in the half-width of the peak, or the like. In this embodiment, the standard deviation of the intensity of the peak of the diffraction ring with respect to the azimuth angle is used as the uniformity index. An example is shown in FIG. 4. FIG. 4A shows a diffraction ring, and FIG. 4B shows the intensity distribution (peak intensity at each position in the circumferential direction of the diffraction ring) with respect to the azimuth angle α in the diffraction ring shown in FIG. 4A, its average value μ, and its standard deviation σ. The horizontal axis of FIG. 4B is the azimuth angle α [deg] from 0° to 360°, and the vertical axis is the diffraction intensity (Diffraction Intensity [counts]). As shown in FIG. 4A, the azimuth angle α is the angle from the baseline in the circumferential direction of the diffraction ring in a clockwise direction, when the baseline (Baseline) passing through the center position O of the diffraction ring is set as the reference 0°. When the standard deviation σ as the uniformity index (=evaluation index) is relatively large, the peak intensity at each position in the circumferential direction of the diffraction ring varies, and metal fatigue is relatively small. On the other hand, when the standard deviation σ is relatively small, the peak intensity at each position in the circumferential direction of the diffraction ring is approximately uniform (the variation is small), and metal fatigue is relatively large.

[0044] The control processing unit 2, memory unit 3, input unit 4, output unit 5 and IF unit 6 can be configured by, for example, a desktop computer, a notebook computer, a tablet computer, etc. If the data acquisition unit 1 is an interface circuit or a communication interface circuit, the IF unit 6 can also be used as the data acquisition unit 1, so the metal fatigue evaluation device D, including the data acquisition unit 1, can be configured by a computer.

[0045] Next, the operation of this embodiment will be described with reference to a flowchart shown in Fig. 5.

[0046] When the power is turned on, the metal fatigue evaluation device D having such a configuration initializes each required part and starts its operation. In the control processing part 2, a control part 21 and an index processing part 22 are functionally configured by executing a control processing program.

[0047] 5, when a command to start evaluation is input, first, the metal fatigue evaluation device D acquires and stores diffraction ring data from the data acquisition unit 1 (S1). More specifically, in this embodiment, the data acquisition unit 1 irradiates the evaluation object Ob with an X-ray beam from the X-ray irradiation unit 14 under the control of the control unit 13, images the diffraction ring with the imaging unit 15 under the control of the control unit 13, and generates diffraction ring data representing the diffraction ring. The data acquisition unit 1 then outputs this diffraction ring data to the control processing unit 2.

[0048] Next, the metal fatigue evaluation device D uses the index processing unit 22 of the control processing unit 2 to determine and store the uniformity index as an evaluation index for the evaluation object Ob (S2). More specifically, in this embodiment, the index processing unit 22 determines the standard deviation σ in the intensity distribution of the diffraction ring with respect to the azimuth angle α as the uniformity index, i.e., the evaluation index.

[0049] Then, the metal fatigue evaluation device D causes the control processing unit 2 to output the determined standard deviation σ as an evaluation index from the output unit 5, and ends this process (S3). Note that, if necessary, the evaluation index may be output from the IF unit 6 to an external device.

[0050] FIG. 6 is a diagram for explaining, as an example, the relationship between the degree of metal fatigue and the standard deviation of strength distribution. The horizontal axis of FIG. 6 is the degree of fatigue damage (Fatigue damage N / Nr [%]), and the vertical axis is the standard deviation (non-uniformity [counts]). FIG. 7 is a diagram for explaining, as an example, the relationship between the degree of metal fatigue and the half-width of the diffraction ring. The horizontal axis of FIG. 7 is the degree of fatigue damage (Fatigue damage N / Nr [%]), and the vertical axis is the half-width (Averaged FWHM [deg]).

[0051] As a comparative example, the half-widths of the diffraction rings obtained by X-ray diffraction with CrKα X-rays incident at an angle of incidence of 0 degrees for each sample (untreated sample) with fatigue damage of 0[%], 10[%], 30[%], 50[%], and 100[%] were almost constant from 0[%] to 100[%] as shown by ● in FIG. 7. This is considered to be due to the influence of the presence of a processing damage layer on the surface of each sample, as described above. The half-widths of the diffraction rings obtained by similar X-ray diffraction for each sample (treated sample) with each damage degree in which the processing damage layer on the surface was removed by electrolytic polishing (EP) were confirmed to increase with the increase in the damage degree from 0[%] to 100[%] as shown by ■ in FIG. 7. Therefore, it was confirmed that the half-widths of the diffraction rings contain information on fatigue damage. However, as described above, the amount of change was about 11[%] from the initial value to the final value. It is assumed that the electrolytic polishing process captures the change in half-width due to fatigue damage, but given that measurement errors may occur depending on the measurement location, a change of approximately 11% cannot be said to be a significant difference that allows for accurate identification of the extent of fatigue damage.

[0052] In contrast, FIG. 6 shows the standard deviation as the evaluation index obtained by the metal fatigue evaluation device D in this embodiment for each sample with each damage level similar to the comparative example described above. In FIG. 6, ● indicates each result of each non-electrolytically polished sample, and ■ indicates each result of each electrolytically polished sample. From FIG. 6, it can be confirmed that the standard deviation σ becomes smaller and the non-uniformity decreases (the uniformity increases) as the damage level increases for both the non-electrolytically polished sample and the electrolytically polished sample. The rate of decrease is a maximum of -71[%] from the initial value for the non-electrolytically polished sample, and a maximum of -83[%] from the initial value for the electrolytically polished sample, and therefore is sufficiently large compared to the change range when the half-width of the comparative example is used as the evaluation index. The variation due to the measurement position is a maximum of 21[%] at a damage level of 0[%] for the electrolytically polished sample, and although there is room for improvement, even in light of this variation, the change in the evaluation index due to fatigue damage can be identified. The rate of change in the evaluation index due to fatigue damage is approximately 70 to 90%, making it a useful evaluation index for evaluating metal fatigue.

[0053] As described above, the metal fatigue evaluation device D in the embodiment and the metal fatigue evaluation method and metal fatigue evaluation program implemented therein calculate a uniformity index indicating the degree of uniformity of peak intensity in the diffraction ring based on the diffraction ring data as an evaluation index indicating the degree of metal fatigue, thereby enabling a more appropriate evaluation of the degree of metal fatigue.

[0054] The metal fatigue evaluation device D, the metal fatigue evaluation method, and the metal fatigue evaluation program generate and acquire diffraction ring data by the data acquisition unit 1, so that metal fatigue can be evaluated at the site of the evaluation target.

[0055] According to this embodiment, it is possible to provide a metal fatigue evaluation device D that determines the standard deviation σ in the intensity distribution of the diffraction ring with respect to the azimuth angle α as the uniformity index, that is, the evaluation index.

[0056] In order to express the present invention, the present invention has been described adequately and sufficiently through the embodiments with reference to the drawings in the above description, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that departs from the scope of the claims described in the claims, the changes or improvements are interpreted as being included in the scope of the claims. [Explanation of symbols]

[0057] D Metal fatigue evaluation device 1 Data Acquisition Section 2. Control processing section 11 High voltage power supply 12 Cooling section 13, 21 Control section 14 X-ray irradiation section 15 Imaging unit 22 Index Processing Section

Claims

1. A metal fatigue evaluation device that calculates an evaluation index that represents a degree of metal fatigue in a metal evaluation object, comprising: a data acquisition unit that acquires diffraction ring data representing an entire diffraction ring formed by irradiating the evaluation object with a beam having a diffractive property; and an index processing unit that calculates, as the evaluation index, a uniformity index that indicates a degree of uniformity of peak intensity over the entire diffraction ring based on the diffraction ring data acquired by the data acquisition unit. Metal fatigue evaluation device.

2. The index processing unit calculates a standard deviation in the intensity distribution of the diffraction ring with respect to the azimuth angle as the uniformity index. The metal fatigue evaluation device according to claim 1 .

3. The data acquisition unit is an irradiation unit that irradiates the beam; an imaging unit that captures an image of an entire diffraction ring formed by irradiating the evaluation object with the beam by the irradiation unit, and generates diffraction ring data representing the entire diffraction ring; The metal fatigue evaluation device according to claim 1 or 2.

4. A metal fatigue evaluation method for determining an evaluation index representing a degree of metal fatigue in a metal evaluation object, comprising the steps of: a data acquisition step of acquiring diffraction ring data representing an entire diffraction ring formed by irradiating the evaluation object with a beam having a diffractive property; and an index processing step of determining, as the evaluation index, a uniformity index representing a degree of uniformity of peak intensity over the entire diffraction ring based on the diffraction ring data acquired in the data acquisition step. Metal fatigue evaluation method.

5. A metal fatigue evaluation program for determining an evaluation index representing a degree of metal fatigue in a metal evaluation object, comprising: On the computer, a data acquisition step of acquiring diffraction ring data representing an entire diffraction ring formed by irradiating the evaluation object with a beam having a diffractive property; an index processing step of determining, as the evaluation index, a uniformity index representing the degree of uniformity of peak intensity over the entire diffraction ring based on the diffraction ring data acquired in the data acquisition step; A metal fatigue evaluation program to carry out the above.

Images