JP2023035256A - Lifespan evaluation system, and lifespan evaluation method - Google Patents

Abstract

To provide a lifespan evaluation system capable of relatively accurately evaluating lifespan evaluation of a nozzle in a short time.SOLUTION: A lifespan evaluation system in at least an embodiment of the disclosure includes: a first stress calculation unit that handles at least one of a nozzle welded portion of a header or piping or a base material around the nozzle hole of the header or the piping in a thermal power plant as a first evaluation portion, which is the object of life evaluation, calculates the stress-lifespan evaluation used in lifespan evaluation for the first evaluation portion based on nozzle type, header size, nozzle size, rated pressure, rated temperature, and steel type relevant to the first evaluation portion; and a first lifespan evaluation unit that evaluates the lifespan of the first evaluation portion based on the stress-lifespan evaluation.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a lifespan evaluation system and a lifespan evaluation method.

High-chromium steel, which is classified as high-strength heat-resistant steel, is used in boiler and piping equipment installed in thermal power plants as the operating temperature rises. The vicinity of the joint with the pipe that is connected to the nozzle is under a severe stress environment where bending stress due to thermal stress, internal pressure, and self-weight is added, so evaluation of creep damage is essential. Conventionally, nozzle creep analysis has been carried out by creep damage evaluation by non-destructive inspection and creep damage evaluation using the finite element method (see Patent Document 1, for example).

Japanese Patent No. 5848224

However, nozzles come in various shapes and sizes, and tendencies of generated stress differ for each shape and size. Therefore, in order to evaluate life appropriately, evaluation by FEM elastic creep analysis is necessary. However, because of the wide variety of nozzle shapes used in thermal power plants, evaluation by FEM elastic creep analysis requires a great deal of time and labor.

In view of the circumstances described above, at least one embodiment of the present disclosure aims to evaluate the service life of a nozzle in a short period of time with relatively high accuracy.

(1) A lifespan evaluation system according to at least one embodiment of the present disclosure,
At least one of a header or a nozzle welded portion of a pipe in a thermal power plant, or a base metal portion around a nozzle hole of the header or the pipe, is defined as a first evaluation portion to be evaluated for life, and the first Based on the nozzle type, main pipe dimensions, nozzle dimensions, evaluation pressure, evaluation temperature, and steel material type related to the evaluation part, the life evaluation stress used to evaluate the life of the first evaluation part is calculated. 1 stress calculation unit;
and a first life evaluation unit that evaluates the life of the first evaluation portion based on the life evaluation stress.

(2) A lifespan evaluation method according to at least one embodiment of the present disclosure,
At least one of a header or a nozzle welded portion of a pipe in a thermal power plant, or a base metal portion around a nozzle hole of the header or the pipe, is defined as a first evaluation portion to be evaluated for life, and the first A step of calculating a life evaluation stress used to evaluate the life of the first evaluation portion based on the nozzle type, main pipe dimensions, nozzle dimensions, evaluation pressure, evaluation temperature, and steel material type related to the evaluation portion. and,
and evaluating the life of the first evaluation portion based on the life evaluation stress.

According to at least one embodiment of the present disclosure, it is possible to evaluate the service life of a nozzle in a short period of time with relatively high accuracy.

1 is a block diagram showing the configuration of a lifespan evaluation system according to this embodiment; FIG. 4 is a flowchart schematically showing a lifespan evaluation procedure for a first evaluation portion of the lifespan evaluation system according to the present embodiment; It is an example of sectional drawing in the vicinity of the nozzle welding part of piping. It is a figure which shows the example of a nozzle type. It is a figure which shows the example of a nozzle type. It is a figure which shows the example of a nozzle type. It is a figure which shows the example of a nozzle type. It is a figure which shows the example of a nozzle type. It is a figure which shows the example of a nozzle type. It is an example of a graph showing the relationship between stress coefficient β and variable βx. It is an example of the table|surface showing the result of life evaluation of the 1st evaluation site|part displayed on an output part. 4 is a flowchart schematically showing a lifespan evaluation procedure for a second evaluation portion of the lifespan evaluation system according to the present embodiment; It is an example of a graph showing the time history of the life evaluation stress σ and the change over time of the cumulative life consumption rate. It is an example of the table|surface showing the result of life evaluation of the 2nd evaluation site|part displayed on an output part.

Several embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as the embodiment or shown in the drawings are not meant to limit the scope of the present disclosure, but are merely illustrative examples. do not have.
For example, expressions denoting relative or absolute arrangements such as "in a direction", "along a direction", "parallel", "perpendicular", "center", "concentric" or "coaxial" are strictly not only represents such an arrangement, but also represents a state of relative displacement with a tolerance or an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "identical", "equal", and "homogeneous", which express that things are in the same state, not only express the state of being strictly equal, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
For example, expressions that express shapes such as squares and cylinders do not only represent shapes such as squares and cylinders in a geometrically strict sense, but also include irregularities and chamfers to the extent that the same effect can be obtained. The shape including the part etc. shall also be represented.
On the other hand, the expressions "comprising", "comprising", "having", "including", or "having" one component are not exclusive expressions excluding the presence of other components.

(Overall configuration of life evaluation system 100)
FIG. 1 is a block diagram showing the configuration of the life evaluation system according to this embodiment.
A life evaluation system according to the present embodiment is a system for evaluating the life of piping in a thermal power plant.
A lifespan evaluation system 100 according to this embodiment includes a processing unit 101 , an input unit 103 , a storage unit 105 and an output unit 107 .
The processing unit 101 is a computer system provided with an input unit 103 , a storage unit 105 and an output unit 107 . Note that the lifespan evaluation system 100 may be a server provided on a network and having the functions of the processing unit 101 . If the processing unit 101 is a server provided on the network, the storage unit 105 may be a database provided on the network, and the input unit 103 and the output unit 107 are terminals connected via the network. may be part of

The input unit 103 is an input device such as a so-called keyboard, mouse, etc., and is used for inputting various data necessary for lifetime evaluation of piping in a thermal power plant.

The processing unit 101 includes a CPU and the like, and executes various programs stored in the storage unit 105 to perform various processes necessary for the life evaluation system 100 . In this embodiment, the processing unit 101 functions as a first stress calculation unit 111, a first life evaluation unit 113, a second stress calculation unit 121, a time history calculation unit 122, and a second life evaluation unit 123. Have as a block. Details of the first stress calculator 111, the first life evaluation unit 113, the second stress calculator 121, the time history calculator 122, and the second life evaluation unit 123 will be described later.

The storage unit 105 stores various programs used for processing in the processing unit 101 and various data necessary for executing the programs.

The output unit 107 is a notification device such as a so-called monitor, and outputs the life evaluation result of the piping of the thermal power plant calculated by the processing unit 101 as output data.

(Concerning life evaluation of piping in thermal power plants)
High-chromium steel, which is classified as high-strength heat-resistant steel, is used in boiler and piping equipment installed in thermal power plants as the operating temperature rises. The vicinity of the joint with the pipe that is connected to the nozzle is under a severe stress environment where bending stress due to thermal stress, internal pressure, and self-weight is added, so evaluation of creep damage is essential.
Nozzles come in various shapes and sizes, and tendencies of generated stress differ for each shape and size. Therefore, in order to evaluate life appropriately, evaluation by FEM elastic creep analysis is necessary. However, because of the wide variety of nozzle shapes used in thermal power plants, evaluation by FEM elastic creep analysis requires a great deal of time and labor.

As a result of diligent studies by the inventors, it was found that FEM elastic creep analysis was performed in advance on a plurality of patterns with different nozzle types and dimensions of each part of the nozzle, and based on the analysis results, the life evaluation stress was parameterized. found that the life evaluation stress can be easily calculated from the nozzle type, header pipe size, nozzle size, evaluated pressure, evaluated temperature, and steel material type. As a result, when evaluating the life of the first evaluation portion, the life of the nozzle can be evaluated with relatively high accuracy without newly performing the FEM elastic creep analysis.

(Regarding Lifetime Evaluation of First Evaluation Portion in Lifetime Evaluation System 100)
Lifespan evaluation in the lifespan evaluation system 100 according to the present embodiment will be described below.
FIG. 2 is a flowchart schematically showing the lifespan evaluation procedure for the first evaluation portion of the lifespan evaluation system 100 according to the present embodiment.
The lifespan evaluation method using the lifespan evaluation system 100 according to the present embodiment comprises step S1 of inputting data on a first evaluation site, step S3 of calculating lifespan evaluation stress, step S5 of lifespan evaluation, and lifespan evaluation. and a step S7 of outputting the result of

(Step S1 of inputting data on the first evaluation site)
The step S<b>1 of inputting data on the first evaluation site according to the present embodiment is a step of inputting various data on the first evaluation site to the processing unit 101 .
Here, the first evaluation part according to the present embodiment is a header of a thermal power plant or a welded part of a nozzle of a pipe of a thermal power plant, and a base metal part around the nozzle hole of the header or the pipe of the thermal power plant. . The first evaluation part may be either a header of a thermal power plant or a welded part of a nozzle of a pipe of a thermal power plant, or a base material part around the nozzle hole of the header or the pipe of the thermal power plant. .
In the following description, the header and piping of the thermal power plant may be simply referred to as piping.

FIG. 3 is an example of a cross-sectional view in the vicinity of a nozzle welded portion of a pipe. In the example of FIG. 3, the first evaluation portion 5 according to the present embodiment includes the nozzle welded portion 41 and the base material portion (nozzle hole surrounding base material portion) 23 .
The nozzle welded portion 41 of the piping of the thermal power plant may be, for example, the nozzle welded portion of the boiler header, or may be the nozzle welded portion of the thermal power plant piping other than the boiler header. The base material portion 23 around the nozzle hole of the piping of the thermal power plant may be, for example, a part where the nozzle hole 21 is formed in the header 20 of the boiler header. It may be a part forming the nozzle hole 21 in .

In step S1 of inputting data about the first evaluation site 5, various data about the first evaluation site 5 may be input from the input unit 103, and the data stored in the storage unit 105 are read out and input to the processing unit 101. may be made.

Various data related to the first evaluation portion 5 to be input to the processing unit 101 in step S1 for inputting data related to the first evaluation portion 5 include data related to the nozzle 30 related to the first evaluation portion 5 to be subjected to life evaluation, Includes evaluation pressure, evaluation temperature, steel type, etc.
The data on the nozzle 30 related to the first evaluation portion 5 includes the nozzle type, main pipe dimensions, and nozzle dimensions, which will be described later.
Here, the evaluation pressure is the internal pressure of the pipe 10 related to the first evaluation portion 5 and the evaluation temperature is the temperature of the pipe 10 related to the first evaluation portion 5 .
The steel material type is the type of material of the pipe 10 related to the first evaluation portion, such as improved 2Cr steel, improved 9Cr steel, and 12Cr steel, which are classified as high-strength heat-resistant steel.

(About nozzle type)
The nozzle type included in the data about the nozzle 30 related to the first evaluation part 5 is the positional relationship between the main pipe 20 and the connection pipe (nozzle) 30, and whether the connection pipe 30 penetrates the main pipe 20. or not, or information indicating which type classified from at least one aspect of the shape of the nozzle stub welded portion 41 .
FIGS. 4A to 4F are diagrams showing examples of nozzle types classified according to the above viewpoints.
The nozzle 30 (nozzle 31) as shown in FIG. 4A is called an A type, the nozzle 30 (nozzle 32) as shown in FIG. 4B is called a B type, and the nozzle 30 (nozzle 32) as shown in FIG. The nozzle 33) is called a C type. The nozzle 30 (nozzle 34) as shown in FIG. 4D is called E type, the nozzle 30 (nozzle 35) as shown in FIG. 4E is called F type, and the nozzle 30 (nozzle 34) as shown in FIG. The nozzle 36) is called a G type.

In the present embodiment, classification is performed based on, for example, the positional relationship between the main pipe 20 and the connection pipe (nozzle 30) as the nozzle type classification axis. In this case, the nozzle type is classified according to whether it is a set-on nozzle or a set-in nozzle. The set-on nozzle is a type of nozzle in which a connection pipe (nozzle 30) is mounted on the mother pipe 20, such as an A-type nozzle 31 shown in FIG. 4A. The set-in nozzle is, for example, a type of nozzle in which the main pipe 20 is counterbored and a connecting pipe is inserted into the counterbored hole, like the B-type nozzle 32 shown in FIG. 4B.

In the present embodiment, as the nozzle type classification axis, for example, classification is performed based on whether or not the connection pipe penetrates the main pipe. For example, in the F-type nozzle 35 shown in FIG. 4E, the connecting pipe (nozzle 35) penetrates the main pipe 20, and in the other types of nozzles 30 shown in FIGS. 4A to 4D and 4F, The connecting pipe (nozzle 30) does not penetrate the mother pipe 20. - 特許庁

In the present embodiment, the nozzle type classification axis may be classified according to, for example, the shape of the welded part of the nozzle or the shape of the groove.
In the present embodiment, as the nozzle type classification axis, for example, the set-in nozzle may be classified according to the depth of the counterbored hole, the taper angle, or the like. For example, the B-type nozzle 32 shown in FIG. 4B has a relatively shallow counterbore, and the G-type nozzle 36 shown in FIG. 4F has a relatively deep counterbore.

(Step S3 for calculating life evaluation stress)
The step S3 of calculating the life evaluation stress according to the present embodiment is used to evaluate the life of the first evaluation portion 5 based on the various data input in the step S1 of inputting the data regarding the first evaluation portion. This is the step of calculating the life evaluation stress σ.

As a result of intensive studies by the inventors, for example, the outer surface hoop stress σθ surface of the header pipe 20, etc., for the stress that is the reference for the life evaluation stress σ, nozzle type, header dimension, nozzle dimension, evaluation pressure, and It was found that the life evaluation stress can be easily calculated by multiplying the stress coefficient β, which is predetermined based on the evaluation temperature and will be described later.

FIG. 5 is an example of a graph showing the relationship between stress coefficient β and variable βx.
The stress coefficient β according to this embodiment is obtained as a value proportional to the variable βx described below.
The variable βx is, for example, in the following equation (1), the outer diameter D of the header 20, the outer diameter d of the nozzle 30, the thickness T of the header 20, the thickness t of the nozzle, and the depth of the counterbore. It is represented by a function with variables such as the width z, the groove angle h, the weld leg length b0, and the like. Note that these variables are the data input in step S1 for inputting data regarding the first evaluation site 5 .
βx=f(D, d, T, t, z, h, b0) (1)

The function for obtaining the variable βx is predetermined for each nozzle type and for each portion of the first evaluation portion (nozzle welded portion 41 and nozzle hole-surrounding base material portion 23). 105. Also, the relationship between the stress coefficient β and the variable βx as shown in FIG. It is stored in the storage unit 105 .
For the first evaluation portion (the base material portion 23 around the nozzle hole), stress coefficients and variables corresponding to the outer diameter wall thickness of the header pipe and the nozzle are determined in advance and stored in the storage unit 105. ing.
In step S3 of calculating the life evaluation stress, the first stress calculation unit 111 in the processing unit 101, based on the nozzle type and the part of the first evaluation part input in step S1 of inputting data on the first evaluation part, A function for obtaining the variable βx and information on the relationship between the stress coefficient β and the variable βx are read from the storage unit 105 . Then, the first stress calculator 111 calculates the variable βx and the stress coefficient β.

Next, the first stress calculator 111 calculates, from the evaluation pressure input in step S1 for inputting data on the first evaluation portion, the stress that serves as a reference for the life evaluation stress σ, such as the outer surface hoop stress σθsurface of the mother pipe 20. Calculate Then, the first stress calculator 111 calculates the life evaluation stress σ by multiplying the calculated stress by the stress coefficient β, for example, as in the following equation (2).
σ=σθsurface×β (2)

(Regarding correction factor Ψ)
In step S3 of calculating the life evaluation stress, the first stress calculation unit 111 further determines a predetermined value based on the inspection result of the pipe 10 and the internal pressure creep test result, as in the following equation (3), for example. The life evaluation stress σ may be calculated in consideration of the correction coefficient Ψ.
In addition, the correction coefficient Ψ is determined in advance based on the inspection result of the pipe 10 and the internal pressure creep test result in order to improve the accuracy of the life evaluation related to the first evaluation portion obtained based on the life evaluation stress σ. is the correction factor. The correction coefficient Ψ is stored in the storage section 105 .
σ=σθsurface×β×ψ (3)

As described above, in the life evaluation system 100 according to the present embodiment, the first stress calculation unit 111 is calculated in advance based on the nozzle type, main pipe dimensions, nozzle dimensions, evaluation pressure, and evaluation temperature. Calculate the life evaluation stress σ in consideration of the stress coefficient β.
As a result, the above stress coefficient β can be obtained immediately from the nozzle type, main pipe dimensions, nozzle dimensions, evaluation pressure, and evaluation temperature. By multiplying by , the life evaluation stress σ can be easily calculated. As a result, the life of the nozzle 30 can be evaluated in a short period of time with relatively high accuracy.

In the life evaluation system 100 according to the present embodiment, the first stress calculator 111 calculates the life evaluation stress σ in consideration of the correction coefficient Ψ predetermined based on the inspection result of the pipe 10 and the internal pressure creep test result. can be calculated.
Thereby, the precision of life evaluation of the nozzle 30 can be improved.

In the life evaluation system 100 according to the present embodiment, the precision of the life evaluation of the nozzle 30 can be improved by considering the nozzle type as described above.

(Step S5 for evaluating life)
The step S5 of evaluating the life according to the present embodiment is a step of evaluating the life of the first evaluation portion 5 based on the life evaluation stress σ calculated in the step S3 of calculating the life evaluation stress. In step S5 of evaluating the life, the first life evaluation section 113 in the processing section 101 calculates the life of the first evaluation portion 5 based on the life evaluation stress σ calculated in step S3 of calculating the life evaluation stress. Specifically, the first life evaluation unit 113 calculates the life by obtaining the creep damage rate of the first evaluation portion 5 for each minute time based on the life evaluation stress σ.
Here, the first life evaluator 113 may calculate the life of the first evaluation portion 5 based on the life evaluative stress σ obtained by the above equation (3). Note that the first life evaluation unit 113 may calculate the life of the first evaluation portion 5 based on the life evaluation stress σ obtained by the above equation (2).

The life calculated in step S5 for evaluating the life includes the initial crack initiation life of the nozzle weld toe 41a (see FIG. 3) related to the first evaluation portion 5, It is at least one of the service life of the material portion 23 and the fracture service life of the nozzle welded portion 41 relating to the first evaluation portion 5 . In the following description, the life calculated in step S5 for evaluating the life is the initial crack initiation life of the nozzle weld toe 41a (see FIG. 3) related to the first evaluation site 5, the nozzle weld toe 41a Alternatively, the lifetime of crack growth from the nozzle internal weld unwelded portion 42a (see FIG. 3), the lifetime of the nozzle hole surrounding base material portion 23 related to the first evaluation portion 5, and the pipe related to the first evaluation portion 5 It is assumed to be the rupture life of the base welded portion 41 .

As described above, the life evaluation system 100 according to the present embodiment, based on the nozzle type, main pipe dimensions, nozzle dimensions, evaluation pressure, evaluation temperature, and steel material type, related to the first evaluation portion 5, A first stress calculator 111 that calculates the life evaluation stress σ used to evaluate the life of the first evaluation portion 5, and a first life evaluation unit that evaluates the life of the first evaluation portion 5 based on the life evaluation stress σ. 113.
As a result, when evaluating the life of the first evaluation portion 5, the life of the pipe 10 including the nozzle 30 can be evaluated with relatively high accuracy without newly performing the FEM elastic creep analysis. Therefore, according to the life evaluation system 100 according to the present embodiment, the life of the pipe 10 including the nozzle 30 can be evaluated in a short time with relatively high accuracy.

In the life evaluation system 100 according to the present embodiment, the first life evaluation unit 113 determines the initial crack initiation life of the nozzle weld toe 41a related to the first evaluation portion 5, the first At least one of the life of the nozzle hole-surrounding base material portion 23 related to the evaluation portion 5 and the fracture life of the nozzle welded portion 41 related to the first evaluation portion 5 is calculated.
As a result, life evaluation corresponding to the form of damage in the pipe 10 including the nozzle 30 can be performed.

In the life evaluation system 100 according to the present embodiment, the first life evaluation part 113 determines the nozzle weld toe part 41a or the nozzle internal weld unwelded part 42a related to the first evaluation part 5 based on the life evaluation stress σ. (See FIG. 3) to calculate the crack growth life.
As a result, the service life can be evaluated by the crack generated from the nozzle weld toe 41a.

The life evaluation method using the life evaluation system 100 according to the present embodiment includes a step S3 of calculating a life evaluation stress and a step S5 of evaluating the life.
As a result, as described above, when evaluating the life of the first evaluation portion 5, the life of the nozzle 30 can be evaluated with relatively high accuracy without newly performing the FEM elastic creep analysis. Therefore, according to the life evaluation method using the life evaluation system 100 according to the present embodiment, the life of the pipe 10 including the nozzle 30 can be evaluated relatively accurately in a short time.

(Step S7 for outputting the result of life evaluation)
The step S7 of outputting the life evaluation result according to the present embodiment is a step of outputting the life of the first evaluation portion 5 calculated in the life evaluation step S5 to the output unit 107 as the life evaluation result. In step S7 for outputting the result of life evaluation, the first lifespan evaluation unit 113 generates display data for displaying the lifespan of the first evaluation site 5 calculated in step S5 for evaluating lifespan on the output unit 107. Output to the output unit 107 . Note that the first lifespan evaluation unit 113 may generate the lifespan of the first evaluation site 5 calculated in the lifespan evaluation step S<b>5 as, for example, voice data and output the data to the output unit 107 . That is, the data output in step S7 for outputting the life evaluation result is not limited to the display data.
FIG. 6 is an example of a table showing the life evaluation results of the first evaluation site 5 displayed on the output unit 107 .

As shown in FIG. 6, in the life evaluation result 70 of the first evaluation site 5 displayed in the output unit 107, various data 71 input in step S1 for inputting data regarding the first evaluation site 5, A result 73 of life evaluation of one evaluation site 5 is included.
As shown in FIG. 6 , the life evaluation result 73 of the first evaluation site 5 includes an initial crack initiation life 731 of the nozzle weld toe 41 a related to the first evaluation site 5 , a nozzle weld toe 41 a Or the life 733 of crack growth from the nozzle internal weld unwelded portion 42a (see FIG. 3), the life 735 of the nozzle hole surrounding base material portion 23 related to the first evaluation portion 5, and the first evaluation portion 5 The fracture life 737 of the nozzle welded portion 41 is included.

Note that the evaluation stress σ1 shown in the life evaluation result 73 of the first evaluation portion 5 is the life evaluation stress σ used to obtain the fracture life 737 of the nozzle weld 41 related to the first evaluation portion 5. be.
The evaluation stress σ2 shown in the life evaluation result 73 of the first evaluation portion 5 is the life evaluation used to obtain the initial crack initiation life 731 of the nozzle weld toe 41a related to the first evaluation portion 5. is the stress σ.
The evaluation stress σ3 shown in the life evaluation result 73 of the first evaluation portion 5 is the life evaluation stress σ used to obtain the crack propagation life 733 from the nozzle weld toe 41a.
The evaluation stress σ4 shown in the life evaluation result 73 of the first evaluation portion 5 is the life evaluation stress σ used to obtain the life 735 of the nozzle hole-surrounding base material portion 23 related to the first evaluation portion 5. be.

(Regarding Lifetime Evaluation of Second Evaluation Portion in Lifetime Evaluation System 100)
Furthermore, life evaluation in the life evaluation system 100 according to this embodiment will be described.
The base material of the pipe 10 of a thermal power plant, the longitudinal welded portion of the pipe 10, and the circumferential welded portion of the pipe 10 are subjected to thermal stress, stress generated by internal pressure, bending stress due to self-weight, and other stresses generated by external forces. works. Since this thermal stress causes a relaxation phenomenon that decreases with time, it is necessary to consider this relaxation phenomenon in order to grasp an appropriate life span. Conventionally, FEM elastic creep analysis was performed for creep damage evaluation (lifetime evaluation) considering the relaxation phenomenon, which required a great deal of time and labor.
In the following description, when the base material portion of the pipe 10 of the thermal power plant, the longitudinal weld portion of the pipe 10, or the circumferential weld portion of the pipe 10 is subject to life evaluation, these parts are the second evaluation. called a site.

Based on the initial stress at the time of design of the second evaluation part, the type of the second evaluation part, the evaluation pressure, the evaluation temperature, and the steel material type, the life evaluation initial stress used to evaluate the life of the second evaluation part is calculated. , Based on the calculated initial stress for life evaluation, the time history of the life consumption rate of the second evaluation part is calculated in consideration of the stress relaxation of the thermal expansion stress at the second evaluation part, so that the life of the second evaluation part is calculated. can be evaluated.
Here, regarding the initial stress at the time of designing the second evaluation part, the analysis result of a general-purpose piping stress analysis system that is generally used in designing the piping 10 is used to estimate the life in consideration of the relaxation phenomenon. The life of the second evaluation portion can be evaluated with relatively high accuracy without performing the FEM elastic creep analysis for the purpose. That is, since the analysis result of the general-purpose piping stress analysis system is obtained at the time of designing the pipe 10, if the initial stress at the time of designing the second evaluation portion included in this analysis result is acquired, the second evaluation portion It is possible to easily calculate the life evaluation initial stress used for life evaluation.
Therefore, in the life evaluation system 100 according to the present embodiment, the life of the second evaluation portion is evaluated as follows.

FIG. 7 is a flow chart schematically showing the lifespan evaluation procedure for the second evaluation portion of the lifespan evaluation system 100 according to the present embodiment.
The life evaluation method using the life evaluation system 100 according to the present embodiment includes step S11 of inputting data on the second evaluation part, step S12 of inputting the initial stress, step S13 of calculating the life evaluation stress, time It has a step S14 of calculating the history, a step S15 of evaluating the life, and a step S17 of outputting the life evaluation result.

(Step S11 for inputting data on the second evaluation site)
The step S<b>11 of inputting data regarding the second evaluation site according to the present embodiment is a step of inputting various data regarding the second evaluation site to the processing unit 101 .
Here, the second evaluation parts according to the present embodiment are the base material part of the pipe 10 of the thermal power plant, the longitudinal welded part of the pipe 10 and the circumferential welded part of the pipe 10 . The second evaluation portion may be any one of the base material portion of the pipe 10 of the pipe of the thermal power plant, the longitudinal welded portion of the pipe 10 , or the circumferential welded portion of the pipe 10 .
The pipe 10 may be a boiler header pipe or a boiler pipe other than the boiler header pipe. The pipe 10 may be the mother pipe 20 or the nozzle 30 .

In step S11 of inputting data regarding the second evaluation site, various data regarding the second evaluation site may be input from the input unit 103, and the data stored in the storage unit 105 are read out and input to the processing unit 101. You may do so.

Various data related to the second evaluation site input to the processing unit 101 in step S11 for inputting data related to the second evaluation site are data related to the dimensions of the pipe 10 related to the second evaluation site that is the target of life evaluation, evaluation Includes pressure, evaluation temperature, steel type, etc.
Here, the evaluation pressure is the internal pressure of the pipe 10 related to the second evaluation portion, and the evaluation temperature is the temperature of the pipe 10 related to the second evaluation portion.
The steel material type is the type of material of the pipe 10 related to the first evaluation portion, such as improved 2Cr steel, improved 9Cr steel, and 12Cr steel, which are classified as high-strength heat-resistant steel.

(Step S12 for inputting initial stress)
The step S12 of inputting the initial stress according to the present embodiment is a step of inputting the initial stress at the time of designing the second evaluation portion. In step S12 of inputting the initial stress, the initial stress at the time of designing the second evaluation portion is acquired from the analysis result of the general-purpose piping stress analysis system obtained at the time of designing the pipe 10 .
For example, if the analysis result of the general-purpose piping stress analysis system or the initial stress at the time of designing the second evaluation part included in the analysis result is stored in advance in the storage unit 105, in step S12 for inputting the initial stress, The initial stress at the time of designing the second evaluation portion can be read out from the storage unit 105 and acquired.

(Step S13 for calculating life evaluation stress)
The step S13 of calculating the life evaluation stress according to the present embodiment is input to the processing unit 101 in the step S12 of inputting the various data input in the step S11 of inputting the data on the second evaluation part and the initial stress. Based on the obtained various data, the initial stress (initial stress for life evaluation) of the life evaluation stress σ used for life evaluation of the second evaluation portion is calculated. In step S13 of calculating the life evaluation stress, the second stress calculation unit 121 of the processing unit 101 inputs the various data input in step S11 of inputting the data on the second evaluation part and the initial stress in step S12. Considering the data of the dimensions of the pipe 10 related to the second evaluation part among the various data input to the processing unit 101, the life evaluation initial stress is calculated from the initial stress at the time of designing the second evaluation part. .

(Step S14 for calculating time history)
According to the present embodiment, step S14 of calculating the time history is based on the life evaluation initial stress calculated in step S13 of calculating the life evaluation stress, taking into account the stress relaxation of the thermal expansion stress at the second evaluation portion. 2 is a step of calculating the time history of the stress relaxation trajectory (the time history of the life evaluation stress σ) of the evaluation site.
FIG. 8 is an example of a graph showing the time history of the life evaluation stress σ and the change over time of the cumulative life consumption rate. In the graph shown in FIG. 8, the horizontal axis is a logarithmic axis regarding elapsed time.
In step S14 for calculating the time history, the time history calculation unit 122 of the processing unit 101 calculates the stress relaxation trajectory after considering the primary creep 91 with a relatively high speed and the secondary creep 92 with a relatively low speed. Calculated by time history.

(Step S15 for evaluating life)
According to the present embodiment, step S15 for evaluating the life is to calculate the life (accumulated life consumption rate) of the second evaluation portion based on the time history of the life evaluation stress σ calculated in step S14 for calculating the time history. It is a step to In step S15 for evaluating the life, the second life evaluation unit 123 of the processing unit 101 calculates the degree of creep damage for each minute time based on the time history of the life evaluation stress σ calculated in step S14 for calculating the time history. By doing so, the cumulative life consumption rate is calculated.
The cumulative life consumption rate is defined as 0 when the initial state of the pipe 10 is not accumulated creep damage, and 1 when the pipe 10 is broken due to accumulated creep damage.

(Step S17 for outputting the result of life evaluation)
The step S17 of outputting the life evaluation result according to the present embodiment is a step of outputting the life of the second evaluation portion calculated in the life evaluation step S15 to the output unit 107 as the life evaluation result. In step S17 for outputting the result of life evaluation, the second life evaluation unit 123 generates and outputs display data for displaying the life of the second evaluation site calculated in step S15 for evaluating life on the output unit 107. Output to the unit 107 . The second lifespan evaluation unit 123 may generate the lifespan of the second evaluation site calculated in step S15 for evaluating the lifespan as, for example, voice data and output the data to the output unit 107 . That is, the data output in step S17 for outputting the life evaluation result is not limited to the display data.
FIG. 9 is an example of a table showing the result of life evaluation of the second evaluation portion displayed on the output unit 107. As shown in FIG.

As shown in FIG. 9, in the life evaluation result 80 of the second evaluation portion displayed in the output unit 107, various data 81 input in step S11 for inputting data on the second evaluation portion and the initial stress are included. Data 82 such as the initial stress at the time of designing the second evaluation portion acquired in step S12 to be input and the life evaluation result 83 of the second evaluation portion are included.
In the example shown in FIG. 9, the life evaluation result 83 of the second evaluation portion includes, for example, if the second evaluation portion is the welded portion of the welded joint, the life of the circumferential welded portion of the welded joint is included. If the second evaluation portion is the base material of the pipe 10, the life of the base material of the pipe 10 is included.

When the second evaluation portion is an elbow or a bent portion such as a bent pipe, the second stress calculator 121 calculates the life evaluation initial stress in consideration of the thickness distribution in the circumferential direction of the elbow or the bent portion. good. When the second evaluation portion is an elbow or a bend portion, the time history calculation section 122 may calculate the above-described time history in consideration of the thickness distribution.
That is, the elbows and vents of the piping 10 of the thermal power plant are manufactured by bending a straight pipe. Therefore, there is a thickness distribution in the circumferential direction at the elbows and bends.
As described above, it is possible to improve the accuracy of life evaluation of the second evaluation portion by considering the thickness distribution in the circumferential direction at the elbow and the bend portion.

(Regarding types of steel)
In some embodiments, the steel material type related to the pipe 10 has been described as high-strength heat-resistant steel, but is not limited to this.
That is, in some embodiments, each part of the pipe 10 may be made of, for example, high chromium steel containing about 9 to 12% by mass of chromium or low alloy steel containing about 1 to 3% by mass of chromium. . In some embodiments, the steel type for pipe 10 may be any of a variety of steels used in creep temperature ranges.

The present disclosure is not limited to the above-described embodiments, and includes modifications of the above-described embodiments and modes in which these modes are combined as appropriate.

The contents described in each of the above embodiments are understood as follows, for example.
(1) The life evaluation system 100 according to at least one embodiment of the present disclosure includes a nozzle welded portion 41 of a header or pipe 10 of a thermal power plant, or a base material around a nozzle hole of the header or pipe 10 of a thermal power plant. At least one of the portions 23 is the first evaluation portion 5 to be evaluated for life, and nozzle type, main pipe dimensions, nozzle dimensions, evaluation pressure, evaluation temperature, and steel material type related to the first evaluation portion 5 A first stress calculator 111 that calculates the life evaluation stress σ used for evaluating the life of the first evaluation portion 5 based on the first stress calculation unit 111 that evaluates the life of the first evaluation portion 5 based on the life evaluation stress σ and a 1 lifespan evaluation unit 113 .

As a result of diligent studies by the inventors, FEM elastic creep analysis was performed in advance on a plurality of patterns with different nozzle types and dimensions of each part of the nozzle, and based on the analysis results, the life evaluation stress σ was parameterized. Therefore, it was found that the life evaluation stress σ can be easily calculated from the nozzle type, header pipe size, nozzle size, evaluation pressure, evaluation temperature, and steel material type. As a result, when evaluating the life of the first evaluation portion 5, the life of the pipe 10 including the nozzle 30 can be evaluated with relatively high accuracy without newly performing the FEM elastic creep analysis. Therefore, according to the configuration (1) above, the service life of the pipe 10 including the nozzle 30 can be evaluated in a short time with relatively high accuracy.

(2) In some embodiments, in the configuration of (1) above, the first life evaluation part 113 determines the initial value of the nozzle weld toe 41a related to the first evaluation part 5 based on the life evaluation stress σ. At least one of the crack initiation life, the life of the nozzle hole-surrounding base material portion 23 related to the first evaluation portion 5, or the fracture life of the nozzle weld portion 41 related to the first evaluation portion 5 may be calculated. .

According to the configuration (2) above, it is possible to evaluate the service life corresponding to the form of damage in the pipe 10 including the nozzle 30 .

(3) In some embodiments, in the configuration of (2) above, the first life evaluator 113 determines whether the nozzle weld toe 41a or pipe It is preferable to calculate the lifetime of crack growth from the unwelded portion 42a (see FIG. 3) of the base-internal weld.

According to the above configuration (3), life can be evaluated by cracks generated from the nozzle weld toe portion 41a or the nozzle internal weld unwelded portion 42a (see FIG. 3).

(4) In some embodiments, in any one of the configurations (1) to (3) above, the first stress calculator 111 calculates the nozzle type, main pipe dimension, nozzle dimension, evaluation pressure, and It is preferable to calculate the life evaluation stress σ in consideration of the stress coefficient β predetermined based on the evaluation temperature.

According to the configuration of (4) above, the above stress coefficient β can be immediately obtained from the nozzle type, main pipe dimensions, nozzle dimensions, evaluated pressure, and evaluated temperature, and the obtained stress coefficient β is used for life evaluation. The life evaluation stress σ can be easily calculated by multiplying the stress that serves as a reference for the stress σ. As a result, the service life of the pipe 10 including the nozzle 30 can be evaluated in a short period of time with relatively high accuracy.

(5) In some embodiments, in the configuration of (4) above, the first stress calculator 111 considers a predetermined correction coefficient Ψ based on the inspection result of the pipe 10 and the internal pressure creep test result. to calculate the life evaluation stress σ.

According to the configuration (5) above, the accuracy of life evaluation of the pipe 10 including the nozzle 30 can be improved.

(6) In some embodiments, in any one of the configurations (1) to (5) above, the nozzle type includes the positional relationship between the main pipe 20 and the connection pipe (nozzle 30), the connection pipe (pipe It is preferable to classify the nozzles based on at least one of whether or not the base 30 ) penetrates the main pipe 20 or the shape of the nozzle welded portion 41 .

According to the above configuration (6), the precision of life evaluation of the pipe 10 including the nozzle 30 can be improved by considering the nozzle types classified from the above point of view.

(7) In some embodiments, in any one of the above configurations (1) to (6), at least the base material portion of the pipe 10, the longitudinal weld portion of the pipe 10, or the circumferential weld portion of the pipe 10 Any one of them is defined as the second evaluation part to be evaluated for life, and based on the initial stress at the time of designing the second evaluation part, the type of the second evaluation part, the evaluation pressure, the evaluation temperature, and the steel material type, A second stress calculator 121 that calculates the life evaluation initial stress used to evaluate the life of the second evaluation portion, and based on the life evaluation initial stress, the stress relaxation of the thermal expansion stress in the second evaluation portion is considered. A time history calculation unit 122 that calculates the time history of the stress relaxation trajectory of the two evaluation sites, and a second life evaluation unit 123 that evaluates the life of the second evaluation site based on the time history may be provided.

According to the above configuration (7), the life of the second evaluation portion is calculated based on the initial stress at the time of designing the second evaluation portion, the type of the second evaluation portion, the evaluation pressure, the evaluation temperature, and the steel material type. Calculate the initial stress for life evaluation used for evaluation, and calculate the time history of the life consumption rate of the second evaluation portion based on the calculated initial stress for life evaluation, taking into consideration the stress relaxation of the thermal expansion stress at the second evaluation portion. Thus, the life of the second evaluation portion can be evaluated.

(8) In some embodiments, in the configuration of (7) above, when the second evaluation portion is an elbow or a bend, the second stress calculator 121 calculates the circumferential direction of the elbow or the bend. It is preferable to calculate the initial stress for life evaluation in consideration of the thickness distribution of . When the second evaluation portion is the elbow or the bend portion, the time history calculation section 122 may calculate the time history in consideration of the thickness distribution.

Bent portions such as elbows and bent pipes of piping 10 of a thermal power plant are manufactured by bending straight pipes. Therefore, the bend portion has a thickness distribution in the circumferential direction.
According to the above configuration (8), the accuracy of life evaluation of the second evaluation portion can be improved by considering the thickness distribution in the circumferential direction in the bend portion.

(9) In some embodiments, in any one of the configurations (1) to (8), the steel material type may include high-chromium steel, which is high-strength heat-resistant steel.

Like the configuration (9), the configurations (1) to (8) are suitable for life evaluation of the piping 10 of a thermal power plant made of high-chromium steel.

(10) A life evaluation method according to at least one embodiment of the present disclosure is a service life evaluation method in which at least one of the nozzle welded portion 41 of the pipe 10 of a thermal power plant or the base material portion 23 around the nozzle hole of the pipe 10 has a life. A first evaluation portion 5 to be evaluated, and based on the nozzle type, main pipe size, nozzle size, evaluation pressure, evaluation temperature, and steel material type related to the first evaluation portion 5, the first evaluation portion 5 (step S3 of calculating the life evaluation stress σ) and a step of evaluating the life of the first evaluation portion 5 based on the life evaluation stress σ (life and a step S5) of evaluating

According to the method (10), as described above, when evaluating the life of the first evaluation portion 5, it is possible to evaluate the life of the nozzle relatively accurately without newly performing the FEM elastic creep analysis. Therefore, according to the method (10), the service life of the pipe 10 including the nozzle 30 can be evaluated in a short time with relatively high accuracy.

5 First evaluation part 10 Piping 20 Main pipe 21 Nozzle hole 23 Nozzle hole surrounding base material 30 Nozzle (connecting pipe)
41 nozzle welded part 41a nozzle weld toe part 42a nozzle internal weld unwelded part 100 life evaluation system 101 processing unit 103 input unit 105 storage unit 107 output unit 111 first stress calculation unit 113 first life evaluation unit 121 2 stress calculation unit 122 time history calculation unit 123 second life evaluation unit

Claims (10)

At least one of a header or a nozzle welded portion of a pipe in a thermal power plant, or a base metal portion around a nozzle hole of the header or the pipe, is defined as a first evaluation portion to be evaluated for life, and the first Based on the nozzle type, main pipe dimensions, nozzle dimensions, evaluation pressure, evaluation temperature, and steel material type related to the evaluation part, the life evaluation stress used to evaluate the life of the first evaluation part is calculated. 1 stress calculation unit;
A life evaluation system comprising: a first life evaluation unit that evaluates the life of the first evaluation portion based on the life evaluation stress. Based on the life evaluation stress, the first life evaluation part determines the initial crack initiation life of the nozzle weld toe related to the first evaluation part, the base material around the nozzle hole related to the first evaluation part, 2. The life evaluation system according to claim 1, which calculates at least one of the life of the part and the rupture life of the nozzle welded part related to the first evaluation part. 3. The life evaluation system according to claim 2, wherein the first life evaluation unit calculates a life of crack growth from the nozzle weld toe of the first evaluation portion based on the life evaluation stress. The first stress calculation unit calculates the life evaluation stress in consideration of a stress coefficient predetermined based on the nozzle type, the dimensions of the main pipe, the dimensions of the nozzle, the evaluation pressure, and the evaluation temperature. 4. The lifespan evaluation system according to any one of claims 1 to 3. 5. The life evaluation system according to claim 4, wherein the first stress calculation unit calculates the life evaluation stress in consideration of a predetermined correction coefficient based on an inspection result of the pipe and an internal pressure creep test result. The nozzle type is classified according to at least one of the positional relationship between the main pipe and the connecting pipe, whether or not the connecting pipe penetrates the main pipe, and the shape of the welded part of the nozzle. The lifespan evaluation system according to any one of claims 1 to 5. At least one of the base metal portion of the pipe, the longitudinal welded portion of the pipe, or the circumferential welded portion of the pipe is set as a second evaluation portion to be evaluated for life, and the second evaluation portion is designed. A second stress calculation for calculating a life evaluation initial stress used for life evaluation of the second evaluation portion based on the initial stress at time, the type of the second evaluation portion, the evaluation pressure, the evaluation temperature, and the steel material type Department and
a time history calculation unit that calculates the time history of the stress relaxation trajectory of the second evaluation portion based on the life evaluation initial stress, taking into consideration the stress relaxation of the thermal expansion stress at the second evaluation portion;
a second life evaluation unit that evaluates the life of the second evaluation portion based on the time history;
The lifespan evaluation system according to any one of claims 1 to 6, comprising: When the second evaluation portion is an elbow or a bend portion, the second stress calculation portion calculates the life evaluation initial stress in consideration of the thickness distribution in the circumferential direction of the elbow or the bend portion. death,
8. The life evaluation system according to claim 7, wherein the time history life calculation section calculates the time history in consideration of the thickness distribution when the second evaluation portion is the elbow or the bend portion. The life evaluation system according to any one of claims 1 to 8, wherein the steel material type includes high-chromium steel, which is high-strength heat-resistant steel. At least one of a header or a nozzle welded portion of a pipe in a thermal power plant, or a base metal portion around a nozzle hole of the header or the pipe, is defined as a first evaluation portion to be evaluated for life, and the first A step of calculating a life evaluation stress used to evaluate the life of the first evaluation portion based on the nozzle type, main pipe dimensions, nozzle dimensions, evaluation pressure, evaluation temperature, and steel material type related to the evaluation portion. and,
and evaluating the life of the first evaluation portion based on the life evaluation stress.

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