Method and system for estimating remaining life of austenitic stainless steel materials

Abstract

To provide a method for estimating a residual life that can estimate a residual life at an arbitrary point of time on the basis of the tissue degradation index of an evaluation target.SOLUTION: In a residual life database constructing step, a residual life database that can extract a tissue / residual life master curve corresponding to an arbitrary load stress is constructed. In a tissue degradation index specification step, the tissue degradation index of an evaluation target at the time of estimation of the residual life is specified. In a stress estimation step, a load stress that acts on the evaluation target after the estimation of the residual life is estimated. In a temperature estimation step, the temperature of the estimation target after the estimation of the residual life is estimated. In a residual life estimation step, the tissue / residual life master curve corresponding to the load stress estimated in the stress estimation step is extracted from the residual life database, and the residual life of the evaluation target is estimated on the basis of the extracted tissue / residual life master curve, the tissue degradation index specified in the tissue degradation index specification step, and the temperature estimated in the temperature estimation step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a remaining life estimation method and a remaining life estimation system for estimating the time from the estimated remaining life after the start of use to creep rupture of an evaluation object made of austenitic stainless steel and used in a creep environment, at the time of remaining life estimation. [Background technology]

[0002] Power generation boilers, various heat exchangers, coal gasification plants, and other equipment use components made of austenitic stainless steel, which has excellent corrosion and heat resistance. For example, in thermal power generation boilers, there is a trend toward higher temperature and pressure steam conditions to improve plant efficiency, and many heat transfer tubes (superheaters, reheaters) made of austenitic stainless steel are used. When austenitic stainless steel is left in a high-temperature, high-pressure environment for a long period of time, creep progresses gradually, and the stainless steel breaks when it reaches its creep life. For this reason, there is a demand for an accurate prediction of the remaining life against creep.

[0003] As a method for predicting the remaining life of a member made of austenitic stainless steel, Patent Document 1 describes a remaining life prediction process including a temperature estimation step of estimating an equivalent temperature equivalent to the use temperature of the evaluation target material based on the σ-phase area ratio and use time of the evaluation target material in a creep environment, and a remaining life estimation step of estimating the remaining life until the evaluation target material creep ruptures based on the estimated equivalent temperature. In the temperature estimation step, the σ-phase area ratio of the evaluation target material is obtained, and the equivalent temperature of the evaluation target material is estimated based on this σ-phase area ratio, the use time of the evaluation target material, and a first relationship graph that has been created. In the remaining life estimation step, a test remaining life is obtained based on the load stress of the evaluation target material, the σ-phase area ratio σ, the equivalent temperature, and a second relationship graph that has been created, and this test remaining life is estimated as the remaining life of the evaluation target material.

[0004] To create the first relationship graph, creep interruption tests and heat aging tests are performed at multiple different test temperatures T using test materials of the same type as the material to be evaluated, sampling is performed every test time t to measure the σ phase area fraction σ of each material used, and data on the σ phase area fraction σ of the test materials, the test temperature T, and the test time t is collected. The Larson-Miller parameter (LMP=T(C+logt): C is a physical constant) is calculated from the collected test temperature T and test time t, and the calculated LMP is used as the X-coordinate and the σ phase area fraction σ of the corresponding test material is used as the Y-coordinate to create the first relationship graph (a curve showing the relationship between LMP and σ phase area fraction σ).

[0005] In creating the second relationship graph, creep rupture tests are performed on multiple test materials with different σ phase area fractions σ at the time creep was interrupted (three types of σ phase area fractions: σ1, σ2, and σ3), the time from creep interruption to rupture for each test material (remaining test life tr) is measured, and data on the applied stress P, σ phase area fractions σ1, σ2, and σ3, test temperature T, and remaining test life tr for each test material is collected. For each of the σ phase area fractions σ1, σ2, and σ3, the LMP is calculated from the test temperature T and remaining test life tr, and a second relationship graph (a curve showing the relationship between LMP and applied stress P) is created with the calculated LMP as the X coordinate and the applied stress P of the test material as the Y coordinate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-35597 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the method of Patent Document 1, the remaining life of an object to be evaluated is estimated based on the applied stress P of the object to be evaluated, the σ phase area fraction σ (an index showing the deterioration of the structure due to aging use: a structure deterioration index), the equivalent temperature T, and a second relationship graph created in advance. The second relationship graph is a graph in which creep rupture tests are performed on test materials having different structure deterioration indexes (σ phase area fractions are σ1, σ2, and σ3), and the test results are approximated to a curve showing the correlation between the LMP (calculated from the test temperature T and the test remaining life tr) and the applied stress P.

[0008] For this reason, remaining life can be estimated only when the microstructural degradation index of the evaluation object at the time of estimating the life (remaining life estimation) matches the tested microstructural degradation index (any of the σ phase area ratios σ1, σ2, or σ3 in the above example), and remaining life cannot be estimated if the microstructural degradation index of the evaluation object at the time of estimating the remaining life does not match the tested microstructural degradation index. In other words, since the microstructural degradation index at the time of estimating the remaining life of the evaluation object is limited, it is not possible to estimate the remaining life based on the microstructural degradation index at any time.

[0009] Therefore, an object of the present invention is to provide a remaining life estimation method and a remaining life estimation system that are capable of estimating the remaining life based on the tissue deterioration index of the evaluation target at any time. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, a first aspect of the method of the present invention is a method for estimating remaining life of an austenitic stainless steel material, which involves using an evaluation object made of austenitic stainless steel in a high-temperature and stress-loaded creep environment, and estimating the remaining life after the evaluation object has started to be used, from the remaining life estimation time until the evaluation object creep rupture, as the remaining life, and includes a remaining life database construction step, a microstructural degradation index identification step, a stress estimation step, a temperature estimation step, and a remaining life estimation step.

[0011] In the remaining life database construction process, the relationship between the microstructural degradation index at an arbitrary point in time in a creep environment for a reference steel material of the same material as the evaluation target, and the remaining life parameters defined by the temperature and remaining life of the reference steel material from the arbitrary point in time until creep rupture, is quantified and formulated as a microstructural / remaining life master curve for each load stress acting on the reference steel material from the arbitrary point in time until creep rupture, thereby constructing a remaining life database from which a microstructural / remaining life master curve corresponding to any load stress can be extracted.

[0012] In the structural deterioration index identifying step, a structural deterioration index of the evaluation object at the time of remaining life estimation is identified. In the stress estimating step, a load stress acting on the evaluation object after the time of remaining life estimation is estimated. In the temperature estimating step, a temperature of the evaluation object after the time of remaining life estimation is estimated. The stress estimation step estimates and identifies a stress representative of a stress history including a maximum stress and an average stress among the stresses acting on the evaluation target during operation as a load stress of the evaluation target. The temperature estimation step estimates and specifies, as the temperature of the evaluation object, a temperature that represents a temperature history including a maximum temperature and an average temperature among the temperatures of the evaluation object during operation up to the time of remaining life estimation.

[0013] In the remaining life estimation step, a microstructure / remaining life master curve corresponding to the applied stress estimated in the stress estimation step is extracted from the remaining life database, and the remaining life of the evaluation object is estimated based on the extracted microstructure / remaining life master curve, the microstructure degradation index identified in the microstructure degradation index identifying step, and the temperature estimated in the temperature estimation step.

[0014] In the remaining life database construction step, the remaining life database can be constructed by the following method. For example, a remaining life evaluation step of a test material that is made of the same material as the evaluation target and that has been subjected to structural degradation under a creep environment is performed in a plurality of steps under test conditions with different structural degradation indices and / or creep environments. In each remaining life evaluation step, the structural degradation index of the test material is quantified based on structural observation of the test material, and then a creep rupture test is performed to measure the rupture time and evaluate the remaining life of the test material. A remaining life parameter calculated from the temperature of the test material from the start of the creep rupture test to creep rupture and the rupture time is obtained for each of the plurality of remaining life evaluation steps. The relationship between the load stress acting on the test material from the start of the creep test to creep rupture and the remaining life parameter is quantified for each structural degradation index as a stress / remaining life master curve. Based on the plurality of stress / remaining life master curves quantified for each structural degradation index, the relationship between the structural degradation index and the remaining life parameter is quantified for each load stress as a structural / remaining life master curve.

[0015] The apparatus of a first aspect of the present invention is a system for estimating remaining life of an austenitic stainless steel material, which uses an evaluation object made of austenitic stainless steel in a high-temperature and stress-loaded creep environment, and, when estimating the remaining life after the start of use of the evaluation object, estimates the time from the remaining life estimation time until the evaluation object creep rupture as the remaining life, and is equipped with a remaining life database, a microstructural degradation index identifying unit, a stress estimation unit, a temperature estimation unit, and a remaining life estimation unit.

[0016] The remaining life database is a database constructed by quantifying and formulating the relationship between the microstructural degradation index at an arbitrary point in time in a creep environment of a reference steel material of the same material as the evaluation target, and the remaining life parameters defined by the temperature and remaining life of the reference steel material from the arbitrary point in time until creep rupture, for each load stress acting on the reference steel material from the arbitrary point in time until creep rupture, as a microstructural / remaining life master curve, and is a database from which a microstructural / remaining life master curve corresponding to any load stress can be extracted.

[0017] The microstructural deterioration index identifying unit identifies a microstructural deterioration index of the evaluation object at the time of remaining life estimation. The stress estimating unit estimates a load stress acting on the evaluation object after the time of remaining life estimation. The temperature estimating unit estimates a temperature of the evaluation object after the time of remaining life estimation. The stress estimation unit estimates and identifies a stress representative of a stress history including a maximum stress and an average stress among the stresses acting on the evaluation object during operation as a load stress of the evaluation object. The temperature estimation unit estimates and specifies, as the temperature of the evaluation object, a temperature that represents a temperature history including a maximum temperature and an average temperature among the temperatures of the evaluation object during operation up to the time of remaining life estimation.

[0018] The remaining life estimation unit extracts a microstructure / remaining life master curve corresponding to the load stress estimated by the stress estimation unit from the remaining life database, and estimates the remaining life of the evaluation object based on the extracted microstructure / remaining life master curve, the microstructure degradation index identified by the microstructure degradation index identifying unit, and the temperature estimated by the temperature estimation unit.

[0019] A method according to a second aspect of the present invention is the remaining life estimation method according to the first aspect, and includes a structure change database construction step and a timing step.

[0020] In the microstructural change database construction step, the relationship between the microstructural deterioration index at any time point in the creep environment of the reference steel and the temperature / time parameter defined by the temperature of the reference steel in the creep environment and the elapsed time up to the any time point is quantified as a microstructural change master curve, thereby constructing the microstructural change database. In the timing step, the elapsed time up to the estimated remaining life of the evaluation target in the creep environment is measured.

[0021] In the microstructural deterioration index identifying step, the microstructural deterioration index of the evaluation object at the time of remaining life estimation is quantified and identified based on the microstructural observation of the evaluation object. In the temperature estimating step, the temperature of the evaluation object before the time of remaining life estimation is estimated based on the microstructural deterioration master curve established in the microstructural change database, the microstructural deterioration index identified in the microstructural deterioration index identifying step, and the time measured in the timing step, and the temperature of the evaluation object after the time of remaining life estimation is estimated based on the estimated temperature before the time of remaining life estimation.

[0022] The device according to a second aspect of the present invention is the remaining life estimation system according to the first aspect, and includes a tissue change database and a timing unit.

[0023] The microstructural change database is a database constructed by quantifying and formulating, as a microstructural change master curve, the relationship between the microstructural deterioration index at any time point in a creep environment of a reference steel material and the temperature / time parameter defined by the temperature of the reference steel material in a creep environment and the elapsed time up to the any time point. The timing unit measures the elapsed time up to the estimated remaining life of the evaluation target in a creep environment.

[0024] The microstructural deterioration index identifying unit quantifies and identifies the microstructural deterioration index of the evaluation object at the time of remaining life estimation based on the microstructural observation of the evaluation object. The temperature estimating unit estimates the temperature of the evaluation object before the time of remaining life estimation based on the microstructural deterioration master curve established in the microstructural change database, the microstructural deterioration index identified by the microstructural deterioration index identifying unit, and the time measured by the timing unit, and estimates the temperature of the evaluation object after the time of remaining life estimation based on the estimated temperature before the time of remaining life estimation.

[0025] A method according to a third aspect of the present invention is the remaining life estimation method according to the first aspect, and includes a microstructural change database construction step, a timing step, and a temperature measurement step.

[0026] In the microstructural change database construction process, the relationship between the microstructural degradation index at any time in a creep environment of the reference steel and the temperature / time parameter defined by the temperature of the reference steel in the creep environment and the elapsed time up to the any time is quantified as a microstructural change master curve, thereby constructing the microstructural change database. In the timing process, the elapsed time up to the estimated remaining life of the evaluation object in the creep environment is measured. In the temperature measurement process, the temperature of the evaluation object in the creep environment up to the estimated remaining life is measured.

[0027] In the microstructural deterioration index identifying step, a microstructural deterioration index of the evaluation object at the time of remaining life estimation is identified based on the microstructural change master curve established in the microstructural change database, the time measured in the timing step, and the temperature measured in the temperature measuring step. In the temperature estimating step, the temperature of the evaluation object after the remaining life estimation is estimated based on the temperature measured in the temperature measuring step.

[0028] The device according to a third aspect of the present invention is the remaining life estimation system according to the first aspect, and includes a microstructural change database, a timing unit, and a temperature measuring unit.

[0029] The microstructural change database is a database constructed by quantifying and formulating, as a microstructural change master curve, the relationship between the microstructural degradation index at any time in a creep environment of a reference steel and the temperature / time parameter defined by the temperature of the reference steel in the creep environment and the elapsed time up to the any time. The timing unit measures the elapsed time up to the remaining life estimation of the evaluation object in the creep environment. The temperature measurement unit measures the temperature of the evaluation object in the creep environment up to the remaining life estimation.

[0030] The microstructural deterioration index identifying unit identifies a microstructural deterioration index of the evaluation object at the time of remaining life estimation based on the microstructural change master curve established in the microstructural change database, the time measured by the timing unit, and the temperature measured by the temperature measuring unit. The temperature estimating unit estimates the temperature of the evaluation object after the remaining life estimation based on the temperature measured by the temperature measuring unit. Effect of the Invention

[0031] According to the present invention, the remaining life can be estimated at any time based on the tissue deterioration index of the evaluation target. [Brief description of the drawings]

[0032] [Figure 1] 1 is a diagram showing an outline of a remaining life estimation method according to an embodiment of the present invention; [Diagram 2] FIG. 13 is a diagram showing an actual equipment temperature evaluation process. [Diagram 3] FIG. 1 is a diagram showing an example of a microstructural change master curve formulated in a database for predicting aging microstructural changes. [Figure 4] This is an image of an actual equipment temperature map (actual measurement) and an actual equipment structural deterioration map (estimated). [Diagram 5] FIG. 1 is a diagram showing an evaluation process for microstructural deterioration of an actual equipment. [Figure 6] This is an image of the actual material structure deterioration map (actual measurement) and the actual equipment temperature map (estimated). [Figure 7] FIG. 1 is a diagram showing the actual equipment damage and remaining life assessment process. [Figure 8] FIG. 1 is a diagram showing an example of a structure / remaining life master curve formulated in an aged structure remaining life prediction database. [Figure 9] 1 is an image diagram of an actual equipment temperature map, an actual equipment structural deterioration map, and an actual equipment remaining life map. FIG. [Figure 10] FIG. 1 is a diagram for explaining a method for formulating a structure / remaining life master curve. [Figure 11] 1 is a block diagram showing a schematic configuration of a remaining life estimation system; [Figure 12] 13 is a flowchart showing a remaining life estimation process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the present invention, the remaining life of an evaluation object made of austenitic stainless steel material and used in a creep environment at high temperature and under stress is estimated (predicted) at the time of estimating the remaining life after the start of use. The time of estimating the remaining life is any time point between the start of use of the evaluation object and creep rupture, and the remaining life is the time from the time of estimating the remaining life to creep rupture. The evaluation object is, for example, any member used in a boiler of a thermal power plant, and in this embodiment, an example will be described in which a heat transfer tube panel of a boiler is the evaluation object. The heat transfer tube panel is a structure in which multiple rows of heat transfer tubes are arranged in the left-right direction of the can and multiple rows in the front-rear direction of the can, and the remaining life of each of the multiple heat transfer tubes is estimated.

[0034] In the following explanation, "actual equipment" refers to the heat transfer tube being evaluated, "in operation" refers to the state in a creep environment, "operating time" refers to the total time the evaluation object was in a creep environment up to the time of remaining life estimation, "acting stress" refers to the load stress acting on the evaluation object during operation, "estimated temperature" refers to the temperature of the evaluation object assumed in a creep environment after the time of remaining life estimation, and "estimated stress" refers to the load stress assumed to act on the evaluation object in a creep environment after the time of remaining life estimation.In the following, an overview of the remaining life estimation method will be given first, followed by details of each process.

[0035] (Outline of remaining life estimation method) As shown in Fig. 1, the remaining life estimation method of this embodiment includes an actual equipment temperature evaluation process P1, an actual equipment microstructural deterioration evaluation process P2, and an actual equipment damage / remaining life evaluation process P3. In the actual equipment temperature evaluation process P1, an actual measured temperature T1 based on temperature measurement (measurement of operating temperature) of the actual equipment during operation and a microstructural deterioration index (estimated microstructural deterioration M2) of the actual equipment at the time of remaining life estimation estimated from the actual measured temperature T1 and the operating time with reference to an aging microstructural change prediction database (microstructural change database) D1 are provided to the actual equipment damage / remaining life evaluation process P3. In the actual equipment microstructural deterioration evaluation process P2, a microstructural deterioration index (actual measured microstructural deterioration M1) of the actual equipment at the time of remaining life estimation quantified based on a microstructural investigation of the actual equipment and a temperature of the actual equipment during operation estimated from the actual measured microstructural deterioration M1 and the operating time with reference to the aging microstructural change prediction database D1 (estimated temperature T2) are provided to the actual equipment damage / remaining life evaluation process P3. Both the actual equipment temperature evaluation process P1 and the actual equipment microstructural deterioration evaluation process P2 may be executed, or only one of them may be executed.

[0036] In the actual equipment damage and remaining life assessment process P3, when estimating the remaining life, the assumed stress and assumed temperature are identified based on the acting stress and temperature during operation of the actual equipment, and the remaining life of the actual equipment is estimated (predicted) from the assumed stress, assumed temperature, and the structural deterioration index at the time of estimating the remaining life, referring to the aging structural remaining life prediction database (remaining life database) D2. When the actual equipment temperature assessment process P1 is executed (when the actual measured temperature T1 and estimated structural M2 are provided), the remaining life is estimated using the actual measured temperature T1 for the temperature during operation of the actual equipment, and the estimated structural M2 for the structural deterioration index at the time of estimating the remaining life. Also, when the actual equipment structural deterioration assessment process P2 is executed (when the estimated temperature T2 and actual measured structural M1 are provided), the remaining life is estimated using the estimated temperature T2 for the temperature during operation of the actual equipment, and the actual measured structural M1 for the structural deterioration index at the time of estimating the remaining life. Since the remaining life is highly correlated with the microstructural deterioration index at the time of estimating the remaining life, in this embodiment, when the measured microstructure M1 is specified (when the actual equipment microstructural deterioration evaluation process P2 is executed), the remaining life is estimated using the estimated temperature T2 and the measured microstructure M1 regardless of whether the actual equipment evaluation process P1 is executed. Note that when both the actual equipment temperature evaluation process P1 and the actual equipment microstructural deterioration evaluation process P2 are executed, the remaining life based on the actual equipment temperature evaluation process P1 and the remaining life based on the actual equipment microstructural deterioration evaluation process P2 may be estimated separately, and the remaining life of the actual equipment may be estimated by taking both into consideration.

[0037] When the remaining life is estimated by the actual equipment damage / remaining life evaluation process P3, it is determined whether there is sufficient remaining life until the next inspection (S10). If there is sufficient remaining life (S10: Yes), a recommendation is made for the actual equipment to be replaced (S11). On the other hand, if there is not enough remaining life (S10: No), a recommendation is made for the immediate replacement of the actual equipment (S12).

[0038] (Actual equipment temperature evaluation process P1) In the above-mentioned actual equipment temperature evaluation process P1, as shown in Fig. 2, the temperature of the actual equipment during operation is measured. In this embodiment, the temperature of a part of heat transfer tubes (measurement target tubes) selected in advance from among the multiple heat transfer tubes constituting the heat transfer tube panel is measured, and the temperatures of the heat transfer tubes other than the measurement target tubes are calculated by thermal calculation from the temperatures of the measurement target tubes. It is also possible to measure the temperatures of all the heat transfer tubes constituting the heat transfer tube panel. Furthermore, the temperature measurement may be performed continuously or intermittently during operation.

[0039] The temperature (actual temperature T1) determined by the measurement and thermal calculation is stored as an actual equipment temperature map (actual measurement) that represents the temperature distribution of the heat transfer tube panel. In the actual equipment temperature map (actual measurement) of the illustrated example, the horizontal axis is set to the row number in the can left-right direction, and the vertical axis is set to the row number in the can front-back direction, and the actual temperature T1 of each heat transfer tube is stored in the corresponding column of the map. In FIG. 4, the state in which the actual temperatures T1 of nine heat transfer tubes, which have row numbers 30 to 32 in the can left-right direction and row numbers 22 to 24 in the can front-back direction, among all the heat transfer tubes, are stored is illustrated as an image diagram of the temperature distribution T. For example, the actual temperature T1 of the heat transfer tube in the 31st row in the can left-right direction and the 23rd row in the can front-back direction is 648°C. Note that the temperature of the actual equipment during operation changes over time, so a temperature representative of the temperature history (for example, the maximum temperature or the average temperature) is determined as the actual temperature T1.

[0040] Next, as shown in Figure 2, the microstructural deterioration index of the actual equipment at the time of remaining life estimation is estimated (aging microstructural deterioration prediction) based on the actual measured temperature T1, the operating time, and the aging microstructural change prediction database D1, and the actual measured temperature T1 and the estimated microstructural deterioration index (estimated microstructural deterioration M2) are provided to the actual equipment damage / remaining life assessment process P3.

[0041] The aging microstructural change prediction database D1 is a database that is constructed in advance by quantifying and formulating, as a microstructural change master curve, the relationship between the microstructural deterioration index (aging microstructural deterioration index) of a reference steel material at an arbitrary time point in a creep environment and a temperature / time parameter defined by the temperature (operating temperature) of the reference steel material in a creep environment and the elapsed time up to the arbitrary time point. The reference steel material is any steel material that is required to be made of the same material as the evaluation target. The microstructural deterioration index is a precipitate property parameter that quantifies the generation state of precipitates (e.g., σ phase (an intermetallic compound composed of Fe and Cr) and carbides) that indicate the degree of aging microstructural deterioration when the reference steel material is used in a creep environment, and is, for example, the area ratio, number density, size, interparticle distance, etc. of the above precipitates. In this embodiment, of these precipitate property parameters, the σ phase area ratio (%) is used as the microstructural deterioration index. In addition, the temperature / time parameter, which is defined by the operating temperature of the reference steel and the elapsed time up to an arbitrary point in time, is a function dependent on time and temperature, and in this embodiment, the Larson-Miller parameter (LMP=T(C+logt): T is temperature, t is time, and C is a physical constant) is used.

[0042] The microstructural change master curve of this embodiment is a curve (an estimated curve of aging microstructural change) showing the correlation between the microstructural deterioration index (σ phase area ratio) and the LMP, as shown in FIG. 3. In estimating the microstructural deterioration index of the actual equipment during remaining life estimation, the LMP (evaluation target LMP) is calculated from the actual measured temperature T1 and the operating time, and the microstructural deterioration index (estimated microstructural change M2) corresponding to the evaluation target LMP is obtained from the microstructural change master curve. The estimated microstructural change M2 is estimated for each heat transfer tube, and is stored as an actual equipment microstructural deterioration map (estimated) showing the deterioration distribution of the heat transfer tube microstructural change, as shown in FIG. 2. The actual equipment microstructural deterioration map (estimated) of the illustrated example is configured in the same manner as the actual equipment temperature map (actual measurement), with the horizontal axis representing the row number in the left-right direction of the can and the vertical axis representing the row number in the front-rear direction of the can, and the estimated microstructural change M2 of each heat transfer tube is stored in the corresponding column of the map. 4 illustrates an example of a state in which the estimated structures M2 of nine heat transfer tubes, of which the row numbers in the can left-right direction are 30 to 32 and the row numbers in the can front-rear direction are 22 to 24, are stored, as an image of structure distribution M. For example, in the case of a heat transfer tube with 31 rows in the can left-right direction and 23 rows in the can front-rear direction, the measured temperature T1 is 648°C (temperature distribution T: image), and the estimated structure M2 (σ phase area ratio) obtained by referring to the aging structure change prediction database D1 (structure change master curve) is 3.6% (structure distribution M: image).

[0043] (Actual equipment structural deterioration evaluation process P2) In the above-mentioned actual equipment microstructural degradation evaluation process P2, as shown in Fig. 5, the structure of the heat transfer tube at the time of estimating the remaining life is investigated (microstructural observation), and the microstructural degradation index of the heat transfer tube is quantified and specified based on the microstructural observation (quantification of aging microstructural degradation). In this embodiment, for example, a sample is taken by removing the tube (cutting out a part of the heat transfer tube), and after etching is performed as necessary, the microstructure of the surface is photographed, and the photographed image is binarized to calculate the σ-phase area ratio (%). Alternatively, the σ-phase area ratio is calculated by the so-called replica method (surface transfer of the heat transfer tube). Note that the method of quantifying the microstructural degradation index based on the microstructural observation is not limited to the above-mentioned method.

[0044] The microstructural deterioration index (measured microstructural M1) specified by the microstructural observation is stored as an actual equipment microstructural deterioration map (measured) showing the deterioration distribution of the heat transfer tube microstructural structure, as shown in FIG. 5. The actual equipment microstructural deterioration map (measured) in the illustrated example is configured similarly to the actual equipment microstructural deterioration map (estimated) shown in FIG. 2, with the horizontal axis being the row number in the can left-right direction and the vertical axis being the row number in the can front-back direction, and the measured microstructural M1 of each heat transfer tube is stored in the corresponding column of the map. FIG. 6 illustrates, as an image diagram of microstructural distribution M, a state in which the measured microstructural M1 of nine heat transfer tubes, of which the row numbers in the can left-right direction are 30 to 32 and the row numbers in the can front-back direction are 22 to 24, among all the heat transfer tubes. For example, the microstructural distribution M1 of a heat transfer tube with 31 rows in the can left-right direction and 23 rows in the can front-back direction is 3.6%.

[0045] Next, as shown in Figure 4, the temperature of the actual equipment during operation is estimated (actual equipment temperature prediction) based on the measured structure M1, operating time, and the aging structure change prediction database D1, and the measured structure M1 and the estimated temperature (estimated temperature T2) are provided to the actual equipment damage / remaining life assessment process P3.

[0046] In estimating the temperature during operation of the actual equipment, the LMP (evaluation target LMP) corresponding to the measured structure M1 is obtained from the structure change master curve (see FIG. 3), and the temperature (estimated temperature T2) is calculated from the obtained evaluation target LMP and the operation time. The estimated temperature T2 is estimated for each heat transfer tube, and is stored as an actual equipment temperature map (estimated) showing the temperature distribution of the heat transfer tube panel, as shown in FIG. 5. The actual equipment temperature map (estimated) in the illustrated example is configured in the same manner as the actual equipment temperature map (actual measurement) shown in FIG. 2, with the row number in the can left-right direction set on the horizontal axis and the row number in the can front-back direction set on the vertical axis, and the estimated temperature T2 of each heat transfer tube is stored in the corresponding column of the map. In FIG. 6, the state in which the estimated temperatures T2 of nine heat transfer tubes with row numbers 30 to 32 in the can left-right direction and row numbers 22 to 24 in the can front-back direction are stored among all the heat transfer tubes is illustrated as an image diagram of the temperature distribution T. For example, in the case of a heat transfer tube with 31 rows in the left-right direction of the can and 23 rows in the front-rear direction of the can, the measured structure M1 (σ phase area ratio) is 3.6% (structure distribution M: image), and the estimated temperature T2 obtained by referring to the aging structure change prediction database D1 (structure change master curve) is 648°C (temperature distribution M: image).

[0047] (Actual equipment damage and remaining life assessment process P3) In the above-mentioned actual equipment damage and remaining life evaluation process P3, as shown in Fig. 7, the remaining life evaluation (estimation of remaining life) is performed using the aging microstructural degradation index based on the acting stress of the actual equipment, the temperature during operation of the actual equipment, the microstructural degradation index of the actual equipment at the time of remaining life judgment, and the aging microstructural remaining life prediction database D2. As described above, when the actual equipment temperature evaluation process P1 is executed and the actual measured temperature T1 and estimated microstructural M2 are provided, the remaining life is estimated using the actual measured temperature T1 for the temperature during operation of the actual equipment and the estimated microstructural M2 for the microstructural degradation index at the time of remaining life estimation. Also, when the actual measured temperature T1 and estimated microstructural M2 are not provided and the actual equipment microstructural degradation evaluation process P2 is executed and the estimated temperature T2 and actual measured microstructural M1 are provided, the remaining life is estimated using the estimated temperature T2 for the temperature during operation of the actual equipment and the actual measured microstructural M1 for the microstructural degradation index at the time of remaining life estimation.

[0048] As shown in Figure 8, the aged structure remaining life prediction database D2 is a database that has been constructed in advance by quantifying and formulating the relationship between the structure degradation index (in this embodiment, the σ phase area ratio) at an arbitrary time point in a creep environment of a reference steel material and the remaining life parameter (in this embodiment, LMP (remaining life LMP)) defined by the temperature (operating temperature) and remaining life of the reference steel material from the arbitrary time point until creep rupture, as a structure / remaining life master curve for each load stress acting on the reference steel material from the arbitrary time point until creep rupture, and is a database from which a structure / remaining life master curve corresponding to an arbitrary load stress (evaluation stress) can be extracted.

[0049] In estimating the remaining life of an actual equipment, as shown in FIG. 7, an assumed stress (a load stress assumed to act on the actual equipment in a creep environment after the remaining life estimation) is estimated and specified based on an acting stress (a load stress acting on the actual equipment during operation). In addition, an assumed temperature (a temperature of the actual equipment assumed in a creep environment after the remaining life estimation) is estimated and specified based on the temperature (actual temperature T1 or estimated temperature T2) of the actual equipment during operation until the remaining life estimation. In this embodiment, the acting stress is specified as the assumed stress, and the actual temperature T1 or estimated temperature T2 is specified as the assumed temperature. Note that an assumed stress different from the acting stress may be specified, and an assumed temperature different from the actual temperature T1 or estimated temperature T2 may be specified. In addition, the actual structure M1 or estimated structure M2 is specified as a structural deterioration index of the actual equipment at the time of the remaining life estimation.

[0050] Next, a structure / remaining life master curve corresponding to the assumed stress is extracted from the remaining life database, a remaining life LMP corresponding to a structure degradation index (actual structure M1 or estimated structure M2) is obtained from the extracted structure / remaining life master curve, and the remaining life (time from remaining life estimation to creep rupture) is calculated from the obtained remaining life LMP and the assumed temperature (actual temperature T1 or estimated temperature T2). For example, when the assumed stress is S4MPa, the structure degradation index (σ phase area ratio) is PX%, and the assumed temperature is TX°C, a structure / remaining life master curve corresponding to S4MPa is extracted, a remaining life LMP corresponding to PX% is obtained from the extracted structure / remaining life master curve, and the remaining life is calculated from the obtained remaining life LMP and TX°C (see Figure 8).

[0051] The calculated remaining life is stored as an actual equipment remaining life map (RL) that shows the remaining life distribution of the heat transfer tubes. In the actual equipment remaining life map (RL) of the illustrated example, the horizontal axis is set to the row number in the left-right direction of the can, and the vertical axis is set to the row number in the front-rear direction of the can, and the remaining life of each heat transfer tube is stored in the corresponding column of the map. Fig. 9 shows an image of the remaining life distribution RL in which the remaining lives of nine heat transfer tubes, of which the row numbers in the left-right direction of the can are 30 to 32 and the row numbers in the front-rear direction of the can are 22 to 24, are stored. For example, in the case of a heat transfer tube with 31 rows in the left-right direction of the can and 23 rows in the front-rear direction of the can, the measured temperature T1 or estimated temperature T2 is 648°C (temperature distribution T: image), the measured structure M1 or estimated structure M2 is 3.6% (structure distribution M: image), and the remaining life obtained by referring to the aging structure remaining life prediction database D2 (structure / remaining life master curve) is 124,021 hours (remaining life distribution RL: image).

[0052] In this way, the aged tissue remaining life prediction database D2 is configured so as to be able to extract a tissue / remaining life master curve (a correlation curve between the tissue deterioration index and the remaining life LMP (a function with operating time and remaining life as variables)) corresponding to any load stress (evaluation stress), so that the remaining life can be estimated at any time based on the tissue deterioration index of the evaluation target.

[0053] (Method of constructing aged tissue remaining life prediction database D2) In this embodiment, the remaining life database is constructed by the following method. First, a remaining life evaluation process of a test material that is made of the same material as the evaluation target and has been subjected to structural degradation under a creep environment is performed in a plurality of steps under test conditions with different structural degradation indices (σ phase area ratio) and / or creep environments (temperature and / or stress). In each remaining life evaluation process, the structural degradation indices of the test material are quantified based on structural observation of the test material, and then a creep rupture test is performed to evaluate the remaining life of the test material (measure the rupture time). Next, a remaining life parameter (remaining life LMP) calculated from the temperature and rupture time of the test material from the start of the creep rupture test to creep rupture is obtained for each of the plurality of remaining life evaluation processes. Next, the relationship between the load stress acting on the test material from the start of the creep test to creep rupture and the remaining life parameter is quantified for each structural degradation index as a stress / remaining life master curve. Finally, based on the plurality of stress / remaining life master curves quantified for each structural degradation index, the relationship between the structural degradation index and the remaining life parameter is quantified for each load stress as a structural / remaining life master curve.

[0054] Figure 10 shows an example of the correspondence between the stress / remaining life master curve and the structure / remaining life master curve. The left side of Figure 10 is a diagram showing the relationship between the applied stress and the remaining life parameters (stress-remaining life correlation diagram). Steel A (σ phase area ratio: a%), Steel B (σ phase area ratio: b%), and Steel C (σ phase area ratio: c%) are all test materials. Creep rupture tests were performed on each of steels A to C under different test stresses (four types, S1, S2, S3, and S4, in the illustrated example), and the results of calculating the remaining life LMP were plotted as test data on the stress-remaining life correlation diagram, and the stress / remaining life master curve for each σ phase area ratio was found by the least squares method.

[0055] The right side of Fig. 10 is a diagram showing the relationship between the microstructural degradation index and the remaining life parameters (stress-remaining life correlation diagram). In this diagram, the stress / remaining life master curve corresponding to the evaluation stress Se is shown. The evaluation stress Se is not the test stress used in the creep rupture test, and the remaining life LMP cannot be calculated directly from the test data. For this reason, the remaining life LMP for each of the σ phase area fractions a%, b%, and c% is obtained from the stress / remaining life master curve for the evaluation stress Se, and the remaining life LMP (evaluation stress Se) corresponding to each σ phase area fraction (a%, b%, c%) is plotted on the microstructural-remaining life correlation diagram, and the microstructural / remaining life master curve for the evaluation stress Se is obtained by the least squares method. By changing the evaluation stress Se, the microstructural / remaining life master curve can be quantified and formulated for each applied stress.

[0056] (Remaining life estimation system) As shown in FIG. 11, the remaining life estimation system of this embodiment is generally composed of a remaining life estimation device 1, a timer 2, a stress measurement unit 3, a temperature measurement unit 4, and a tissue imaging unit 5. The timer 2 measures the operating time of the actual equipment and provides it to the remaining life estimation device 1. The stress measurement unit 3 measures the acting stress of the actual equipment and / or calculates it by FEM calculation or the like and provides it to the remaining life estimation device 1. The temperature measurement unit 4 measures the temperature (actual measured temperature T1) during operation of the actual equipment and provides it to the remaining life estimation device 1. The tissue imaging unit 5 photographs the microstructure of the surface of the actual equipment and provides the image data (tissue precipitation data) to the remaining life estimation device 1. The timer 2 may be an external timer provided outside the remaining life estimation device 1 as shown in FIG. 11, or may be an internal timer of the remaining life estimation device 1.

[0057] The remaining life estimation device 1 is configured, for example, by a computer, and includes an arithmetic processing unit 6 and a storage unit 7. An aging microstructural change prediction database D1 and an aging microstructural remaining life prediction database D2 are constructed and stored in advance in the storage unit 7. Furthermore, each map (actual equipment temperature map, actual equipment microstructural deterioration map, actual equipment remaining life map) with blank data is set in advance in the storage unit 7, and the arithmetic processing unit 6 creates each map by appropriately storing corresponding data in each map.

[0058] The calculation processing unit 6 executes the actual equipment temperature evaluation process P1, the processing after photography in the actual equipment microstructural degradation evaluation process P2, and the actual equipment damage / remaining life evaluation process P3. That is, the calculation processing unit 6 functions as a microstructural degradation index identifying unit that identifies the microstructural degradation index of the actual equipment at the time of remaining life estimation, a stress estimation unit that estimates the load stress acting on the actual equipment after the time of remaining life estimation, a temperature estimation unit that estimates the temperature of the actual equipment after the time of remaining life estimation, and a remaining life estimation unit that extracts a microstructural / remaining life master curve corresponding to the load stress estimated by the stress estimation unit from the aged microstructural remaining life prediction database D1, and estimates the remaining life of the actual equipment based on the extracted microstructural / remaining life master curve, the microstructural degradation index identified by the microstructural degradation index identifying unit, and the temperature estimated by the temperature estimation unit. In addition, since the load stress acting on the actual equipment during operation (stress measured by the stress measurement unit 3) and the temperature of the actual equipment (stress measured by the temperature measurement unit 4) vary over time, the calculation processing unit 6 identifies the stress that represents the stress history (maximum stress, average stress, etc.) as the acting stress, and identifies the temperature that represents the temperature history (maximum temperature, average temperature, etc.) as the actual measured temperature T1.

[0059] (Remaining life estimation process) The remaining life estimation process executed by the remaining life estimation device 1 will be described with reference to FIGS.

[0060] The remaining life estimation process is started by determining an evaluation object (S20). In this embodiment, a heat transfer tube (heat transfer tube panel) is the evaluation object, and the evaluation object is determined by an instruction input from an evaluator or the like to the remaining life estimation device 1. The evaluation object can be determined at any time from the start of operation of the evaluation object to the time of remaining life evaluation, but considering the timing of operation time and measurement of acting stress, it is preferable to determine the evaluation object before the start of operation.

[0061] When the evaluation target is determined, the operation time of the evaluation target is acquired and the acting stress is identified (S21). The operation time is acquired from the timer unit 2 at the time of evaluation judgment. The acting stress is identified based on the stress provided from the stress measurement unit 3 at the time of a preset measurement during operation (the stress measured by the stress measurement unit 3 and / or the stress calculated by FEM calculation or the like). Although not shown, if the temperature of the evaluation target during operation can be measured, the temperature is acquired from the temperature measurement unit 4 as necessary and stored in the memory unit 7. In addition, when the evaluation target is determined after the start of operation (for example, when the remaining life is estimated) (when the determination in S20 is made after the start of operation), the stress and temperature during operation of the components that may be the evaluation target are acquired and stored in the memory unit 7.

[0062] When judging the remaining life, the structure / remaining life master curve corresponding to the acting stress identified in S21 is read out from the aged structure remaining life prediction database D2 (S22).

[0063] In addition, when judging the remaining life, it is judged whether or not a structural investigation has been performed (whether or not the structural deterioration index of the evaluation target has been quantified) (S23). If a structural investigation has been performed (S23: Yes), the process proceeds to CASE1, and the actual equipment structural deterioration evaluation process P2 and the actual equipment damage / remaining life evaluation process P3 are executed.

[0064] In CASE 1, the microstructural degradation index of the heat transfer tube is quantified based on the microstructural observation, and an actual equipment microstructural degradation map (actual measurement) (microstructural degradation distribution map (actual measurement: σ phase quantification)) is created (S24).

[0065] Next, the microstructure change master curve is read from the aging microstructure change prediction database D1, the evaluation target LMP corresponding to each measured structure M1 of the microstructure deterioration distribution map created in S24 is obtained from the microstructure change master curve, and the temperature during operation of the evaluation target is calculated from each evaluation target LMP and the operating time to create an actual equipment temperature map (estimated) (temperature distribution map (estimated)) (S26). In addition, an assumed stress is specified based on the acting stress, a microstructure / remaining life master curve corresponding to the assumed stress is read from the remaining life database, and the remaining life LMP corresponding to each measured structure M1 of the microstructure deterioration distribution map created in S24 is obtained from the microstructure / remaining life master curve to create a remaining life LMP distribution map (estimated) (S25). The remaining life LMP distribution map (estimated) is configured in the same manner as the actual equipment temperature map, the actual equipment microstructure deterioration map, etc., and represents the distribution of the remaining life LMP.

[0066] Finally, an assumed temperature is identified from each estimated temperature T2 in the temperature distribution map (estimated) created in S26, and the remaining life is calculated from each remaining life LMP and the assumed temperature in the remaining life LMP distribution map created in S25, to create an actual equipment remaining life map (RL) (remaining life tr distribution map) (S27), and the replacement timing and replacement scope are determined based on the created remaining life tr distribution map (S28).

[0067] If a structural investigation has not been performed (S23: No), it is determined whether or not an actual temperature measurement has been performed (whether or not the temperature of the evaluation target during operation has been acquired) (S29). If an actual temperature measurement has been performed (S29: Yes), the process proceeds to CASE 2, and actual equipment temperature evaluation process P1 and actual equipment damage / remaining life evaluation process P3 are executed.

[0068] In CASE 2, the temperature of the evaluation target during operation is identified through measurement and thermal calculation, and an actual equipment temperature map (actual measurement) (temperature distribution map (actual measurement and thermal calculation)) is created (S30).

[0069] Next, a microstructural change master curve is read from the aging microstructural change prediction database D1, an evaluation target LMP is calculated from each measured temperature T1 and operation time of the temperature distribution map created in S30, a microstructural deterioration index (estimated microstructural M2) corresponding to the evaluation target LMP is obtained from the microstructural change master curve, and an actual equipment microstructural deterioration map (estimated) (microstructural deterioration distribution map (estimated)) is created (S31). In addition, an assumed stress is specified based on the acting stress, a microstructural / remaining life master curve corresponding to the assumed stress is read from the remaining life database, and a remaining life LMP corresponding to each estimated microstructural M2 of the microstructural deterioration distribution map created in S31 is obtained from the microstructural / remaining life master curve, thereby creating a remaining life LMP distribution map (estimated) (S25).

[0070] Finally, an expected temperature is identified from each measured temperature T1 in the temperature distribution map created in S30, and the remaining life is calculated from each remaining life LMP and the expected temperature in the remaining life LMP distribution map created in S25 to create an actual equipment remaining life map (RL) (remaining life tr distribution map) (S27), and the replacement timing and replacement scope are determined based on the created remaining life tr distribution map (S28).

[0071] If neither the structure investigation nor the temperature measurement has been performed (S29: No), the process proceeds to CASE3.

[0072] In CASE 3, the temperature during operation of the design evaluation target of the plant etc. (in this embodiment, a boiler) in which the evaluation target is installed is identified as a temperature (design temperature) in place of the actual measured temperature T1 and the estimated temperature T2, and a temperature distribution map (design / operation / thermal calculation) is created in the same way as in the case of the actual measured temperature T1 and the estimated temperature T2 (S32).

[0073] Next, a microstructural change master curve is read from the aging microstructural change prediction database D1, an evaluation target LMP is calculated from each test temperature T3 and operation time of the temperature distribution map created in S32, a microstructural deterioration index (estimated microstructural M3) corresponding to the evaluation target LMP is obtained from the microstructural change master curve, and a microstructural deterioration map (estimated) is created in the same manner as in the case of the estimated microstructural M2 (S33). In addition, an assumed stress is specified based on the acting stress, a microstructural / remaining life master curve corresponding to the assumed stress is read from the remaining life database, and a remaining life LMP corresponding to each estimated microstructural M2 of the microstructural deterioration distribution map created in S33 is obtained from the microstructural / remaining life master curve, thereby creating a remaining life LMP distribution map (estimated) (S25).

[0074] Finally, an assumed temperature is identified from each design temperature T3 in the temperature distribution map created in S33, and the remaining life is calculated from each remaining life LMP and the assumed temperature in the remaining life LMP distribution map created in S25 to create an actual equipment remaining life map (RL) (remaining life tr distribution map) (S27), and the replacement timing and replacement scope are determined based on the created remaining life tr distribution map (S28).

[0075] The present invention is not limited to the above-described embodiments and modified examples which have been described as examples, and various modifications may be made depending on the design, etc., other than the above-described embodiments, etc., as long as they do not deviate from the technical idea of ​​the present invention. [Explanation of symbols]

[0076] 1:Remaining life estimation device 2: Timing section 3: Stress measurement section 4: Temperature measurement section 5: Histology Department 6: Calculation processing unit (structural deterioration index identification unit, stress estimation unit, temperature estimation unit, remaining life estimation unit) 7: Storage part D1: Database of predictions of aging structural changes (structural change database) D2: Aging organization remaining life prediction database (remaining life database)

Claims

1. A method for estimating remaining life of an austenitic stainless steel material, comprising using an evaluation object made of austenitic stainless steel in a creep environment at high temperature and under stress, and estimating a remaining life of the evaluation object after the start of use of the evaluation object from the estimated remaining life to a time until the evaluation object creep rupture, comprising: a remaining life database construction process for constructing a remaining life database from which a structure / remaining life master curve corresponding to any load stress can be extracted by quantifying and formulating a relationship between a structure degradation index at any time point in a creep environment for a reference steel material of the same material as the evaluation target and a remaining life parameter defined by the temperature and remaining life of the reference steel material from the any time point until creep rupture for each load stress acting on the reference steel material from the any time point until creep rupture, as a structure / remaining life master curve; a microstructural deterioration index identifying step of identifying a microstructural deterioration index of the evaluation target at the time of estimating the remaining life; a stress estimating step of estimating a load stress acting on the evaluation object after the remaining life estimation; a temperature estimation step of estimating a temperature of the evaluation object after the remaining life estimation time; a remaining life estimation step of extracting from the remaining life database a structure / remaining life master curve corresponding to the applied stress estimated in the stress estimation step, and estimating a remaining life of the evaluation object based on the extracted structure / remaining life master curve, the structure deterioration index identified in the structure deterioration index identification step, and the temperature estimated in the temperature estimation step, The stress estimation step estimates and identifies a stress representative of a stress history including a maximum stress and an average stress among stresses acting on the evaluation target during operation as a load stress of the evaluation target; The temperature estimation step estimates and specifies, as the temperature of the evaluation object, a temperature representative of a temperature history including a maximum temperature and an average temperature among the temperatures of the evaluation object during operation up to the remaining life estimation time. A method for estimating remaining life of an austenitic stainless steel material, comprising:

2. 2. A remaining life estimation method according to claim 1, comprising the steps of: In the remaining life database construction step, a microstructural degradation index of a test material that is made of the same material as the evaluation target and that has been microstructurally degraded under a creep environment is quantified based on a microstructural observation of the test material, and then a remaining life evaluation step of conducting a creep rupture test to evaluate the remaining life of the test material is performed in a plurality of steps under test conditions with different microstructural degradation indexes and / or creep environments, a remaining life parameter calculated from the temperature of the test material from the start of the creep rupture test to creep rupture and the rupture time is obtained for each of the plurality of remaining life evaluation steps, a relationship between the load stress acting on the test material from the start of the creep test to creep rupture and the remaining life parameter is quantified for each microstructural degradation index as a stress / remaining life master curve, and the relationship between the microstructural degradation index and the remaining life parameter is quantified for each load stress as a microstructural / remaining life master curve based on the plurality of stress / remaining life master curves quantified for each microstructural degradation index, thereby constructing the remaining life database. A method for estimating remaining life of an austenitic stainless steel material, comprising:

3. 3. A remaining life estimation method according to claim 1 or 2, comprising: a microstructural change database construction step of constructing a microstructural change database by quantifying and formulating a relationship between a microstructural deterioration index at an arbitrary time point in a creep environment of the reference steel material and a temperature / time parameter defined by the temperature of the reference steel material in a creep environment and the elapsed time up to the arbitrary time point as a microstructural change master curve; and a timing step of measuring an elapsed time until the remaining life of the evaluation object is estimated under a creep environment, In the step of identifying a microstructural deterioration index, a microstructural deterioration index of the evaluation object at the time of estimating the remaining life is quantified and identified based on a microstructural observation of the evaluation object, In the temperature estimation step, a temperature of the evaluation object before the remaining life estimation time is estimated based on a microstructural deterioration master curve established in the microstructural change database, a microstructural deterioration index identified in the microstructural deterioration index identification step, and a time measured in the timing step, and a temperature of the evaluation object after the remaining life estimation time is estimated based on the estimated temperature before the remaining life estimation time. A method for estimating remaining life of an austenitic stainless steel material, comprising:

4. 3. A remaining life estimation method according to claim 1 or 2, comprising: a microstructural change database construction step of constructing a microstructural change database by quantifying and formulating a relationship between a microstructural deterioration index at an arbitrary time point in a creep environment of the reference steel material and a temperature / time parameter defined by the temperature of the reference steel material in a creep environment and the elapsed time up to the arbitrary time point as a microstructural change master curve; a timing step of measuring an elapsed time until the remaining life of the evaluation object is estimated under a creep environment; and a temperature measuring step of measuring a temperature of the evaluation object in a creep environment until the remaining life estimation time, In the microstructural deterioration index identifying step, a microstructural deterioration index of the evaluation target at the time of estimating the remaining life is identified based on a microstructural change master curve established in the microstructural change database, the time measured in the timing step, and the temperature measured in the temperature measuring step; In the temperature estimation step, a temperature of the evaluation object after the remaining life estimation time is estimated based on the temperature measured in the temperature measurement step. A method for estimating remaining life of an austenitic stainless steel material, comprising:

5. A system for estimating remaining life of an austenitic stainless steel material, comprising: an evaluation object made of an austenitic stainless steel, which is used in a creep environment at high temperature and under stress; and, when estimating remaining life after starting use of the evaluation object, estimating a time from the remaining life estimation to creep rupture of the evaluation object as remaining life, comprising: a remaining life database that is constructed by quantifying and formulating the relationship between a microstructural degradation index at an arbitrary time point in a creep environment for a reference steel material of the same material as the evaluation target, and a remaining life parameter defined by the temperature and remaining life of the reference steel material from the arbitrary time point until creep rupture, for each load stress acting on the reference steel material from the arbitrary time point until creep rupture, as a microstructural / remaining life master curve, and from which a microstructural / remaining life master curve corresponding to an arbitrary load stress can be extracted; a microstructural deterioration index identifying unit that identifies a microstructural deterioration index of the evaluation target at the time of estimating the remaining life; a stress estimation unit that estimates a load stress acting on the evaluation target after the remaining life estimation; a temperature estimation unit that estimates a temperature of the evaluation object after the remaining life estimation time; a remaining life estimation unit that extracts a microstructure / remaining life master curve corresponding to the load stress estimated by the stress estimation unit from the remaining life database, and estimates a remaining life of the evaluation object based on the extracted microstructure / remaining life master curve, the microstructure deterioration index identified by the microstructure deterioration index identification unit, and the temperature estimated by the temperature estimation unit, the stress estimation unit estimates and identifies a stress representative of a stress history including a maximum stress and an average stress among stresses acting on the evaluation object during operation as a load stress of the evaluation object; The temperature estimation unit estimates and specifies, as the temperature of the evaluation object, a temperature representative of a temperature history including a maximum temperature and an average temperature among temperatures of the evaluation object during operation up to a remaining life estimation time. A system for estimating remaining life of an austenitic stainless steel material, comprising:

6. The remaining life estimation system according to claim 5, A microstructural change database constructed by quantifying and formulating a relationship between a microstructural deterioration index at an arbitrary time point in a creep environment of the reference steel material and a temperature / time parameter defined by the temperature of the reference steel material in a creep environment and the elapsed time up to the arbitrary time point as a microstructural change master curve; a timing unit that measures an elapsed time until the remaining life of the evaluation object under a creep environment is estimated, the microstructural deterioration index identifying unit quantifies and identifies a microstructural deterioration index of the evaluation object at the time of the remaining life estimation based on a microstructural observation of the evaluation object, The temperature estimation unit estimates a temperature of the evaluation object before the remaining life estimation time based on a microstructural deterioration master curve established in the microstructural change database, a microstructural deterioration index identified by the microstructural deterioration index identification unit, and a time measured by the timing unit, and estimates a temperature of the evaluation object after the remaining life estimation time based on the estimated temperature before the remaining life estimation time. A system for estimating remaining life of an austenitic stainless steel material, comprising:

7. The remaining life estimation system according to claim 5, a microstructural change database constructed by quantifying and formulating a relationship between a microstructural deterioration index at an arbitrary time point in a creep environment of the reference steel material and a temperature / time parameter defined by a temperature of the reference steel material in a creep environment and an elapsed time up to the arbitrary time point as a microstructural change master curve; a timing unit that measures an elapsed time until the remaining life of the evaluation object under a creep environment is estimated; and a temperature measuring unit that measures a temperature of the evaluation object in a creep environment until the remaining life estimation time, the microstructural deterioration index identifying unit identifies a microstructural deterioration index of the evaluation object at the time of estimating the remaining life based on a microstructural change master curve established in the microstructural change database, the time measured by the timing unit, and the temperature measured by the temperature measuring unit; The temperature estimation unit estimates a temperature of the evaluation object after the remaining life estimation time based on the temperature measured by the temperature measurement unit. A system for estimating remaining life of an austenitic stainless steel material, comprising:

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