JP6853212B2 - Inspection method for heat-resistant materials - Google Patents

Description

The present disclosure relates to a method for inspecting heat-resistant members.

In order to evaluate the life of a steel material used for high heat equipment such as a boiler, the operating temperature of the steel material is estimated based on the state of the structure of the steel material surface. For example, Patent Document 1 discloses a method in which the relationship between the average interparticle distance of precipitates and temperature / time parameters is obtained in advance, and the operating temperature is estimated from the average interparticle distance of precipitates in the steel material to be inspected. ing.
Further, for example, in Patent Document 2, the area ratio, the number density or the average size of the precipitates in the unit area, the relationship between the operating time and the operating temperature are obtained in advance, and the precipitates in the steel material to be inspected have a unit area. A method of estimating the operating temperature from the area ratio, the number density, or the average size occupied therein is disclosed.

Japanese Unexamined Patent Publication No. 2015-125116 Japanese Unexamined Patent Publication No. 2014-228196

However, when the use of steel materials is started at high temperature, the frequency of occurrence of new precipitates increases shortly after the start of use, so that the average interparticle distance decreases, and then new precipitates are generated. As the frequency decreases, the average interparticle distance begins to increase. Therefore, in the method disclosed in Patent Document 1, there is a possibility that the operating temperature estimated from the average interparticle distance of the precipitates in the steel material to be inspected may not be uniquely determined.
In addition, when the use of steel materials is started at a high temperature, at a certain time, there may be both a precipitate that becomes coarser with the passage of time and a precipitate that becomes smaller and disappears. There is a period during which no clear change in the area ratio, number density or average size of the precipitates in the unit area is observed. Therefore, the method disclosed in Patent Document 2 may reduce the accuracy of estimating the operating temperature.

In view of the above circumstances, at least one embodiment of the present invention aims to provide a method for inspecting a heat-resistant member capable of accurately estimating the operating temperature of a steel material based on the state of the structure of the surface of the steel material.

(1) The method for inspecting a heat-resistant member according to at least one embodiment of the present invention is as follows.
A relationship acquisition step for acquiring the relationship between the average particle size of the precipitate having the first particle size or more in the structure of the heat-resistant material and the parameters related to the operating temperature and the operating time of the heat-resistant material.
Among the precipitates in the structure of the heat-resistant member to be inspected, the average particle size acquisition step of obtaining the average particle size of the precipitates having the second particle size or more, which is the particle size corresponding to the first particle size, by measurement.
An operating temperature parameter acquisition step of obtaining a parameter relating to the operating temperature of the heat-resistant member to be inspected based on the relationship acquired in the relationship acquisition step and the average particle size obtained in the average particle size acquisition step.
To be equipped.

According to the method (1) above, the relationship acquisition for acquiring the relationship between the average particle size of the precipitates having the first particle size or more in the structure of the heat-resistant material and the parameters related to the operating temperature and the operating time of the heat-resistant material. Have a process. Therefore, in the above-mentioned relationship obtained, the influence of the precipitate having a particle size smaller than the first particle size can be eliminated. As a result, in the above-mentioned acquired relationship, the influence of newly generated precipitates and the influence of the precipitates disappearing with the passage of time can be suppressed, so that the above-mentioned acquired relationship is suitable for estimating the operating temperature. It becomes a thing.
Further, according to the method (1) above, the average particle size of the precipitates having the second particle size or more, which is the particle size corresponding to the first particle size, among the precipitates in the structure of the heat-resistant member to be inspected is measured. It is provided with a desired average particle size acquisition step. Therefore, the influence of the precipitate having a particle size smaller than the second particle size, which is the particle size corresponding to the first particle size, can be excluded from the average particle size of the precipitate in the structure of the heat-resistant member to be inspected, which is obtained in the average particle size acquisition step. ..
Then, according to the method (1) above, the parameters related to the operating temperature of the heat-resistant member to be inspected are obtained based on the relationship acquired in the relationship acquisition step and the average particle size obtained in the average particle size acquisition step. It is equipped with an operating temperature parameter acquisition process. As a result, the parameters related to the operating temperature of the heat-resistant member to be inspected can be obtained in a state where the influence of precipitates having a predetermined particle size is excluded, so that the estimation accuracy of the operating temperature of the heat-resistant member to be inspected can be improved.

(2) In some embodiments, in the method of (1) above,
The first particle size is n micrometers.
The second particle size is n micrometer.

According to the method (2) above, both the first particle size and the second particle size are n micrometers. As a result, the selection criteria for whether or not the precipitate is to be calculated for the average particle size can be aligned between the heat-resistant material and the heat-resistant member to be inspected, so that the estimation is based on the state of the surface structure of the heat-resistant member to be inspected. The accuracy of estimating the operating temperature of the heat-resistant member to be inspected can be improved.

(3) In some embodiments, in the method (1) above,
The first particle size is the particle size of the nth precipitate in order from the deposit having the largest diameter among the precipitates in the structure of the heat-resistant material.
The second particle size is the particle size of the nth precipitate in order from the deposit having the largest diameter among the precipitates in the structure of the heat-resistant member to be inspected.

According to the method (3) above, the first particle size is the particle size of the nth precipitate in order from the precipitate having the largest diameter among the precipitates in the structure of the heat-resistant material, and the second particle size is It is the particle size of the nth precipitate in order from the precipitate having the largest diameter among the precipitates in the structure of the heat-resistant member to be inspected. As a result, the first particle size and the second particle size can be brought close to each other, so that the selection criteria for whether or not the precipitate is to be calculated for the average particle size are aligned between the heat-resistant material and the heat-resistant member to be inspected. Be done. Therefore, it is possible to improve the estimation accuracy of the operating temperature of the heat-resistant member to be inspected, which is estimated based on the state of the surface structure of the heat-resistant member to be inspected.
In addition, if the size of the region where the precipitate is investigated to calculate the average particle size is approximately the same for the heat-resistant material and the heat-resistant member to be inspected, the precipitate used for calculating the average particle size is selected. In order to do so, n precipitates may be selected in order from the precipitate having the maximum diameter, so that the precipitate used for calculating the average particle size can be easily selected. Therefore, it is possible to improve the work efficiency when investigating the precipitate in order to calculate the average particle size.

(4) In some embodiments, in the method (1) above,
The first particle size is the particle size of the smallest precipitate in the precipitates contained in the number of the upper n% having a large particle size among the precipitates in the structure of the heat-resistant material.
The second particle size is the smallest particle size of the precipitates contained in the number of the upper n% having a large particle size among the precipitates in the structure of the heat-resistant member to be inspected.

According to the method (4) above, the first particle size is the particle size of the smallest precipitate among the precipitates contained in the number of the upper n% having a large particle size among the precipitates in the structure of the heat-resistant material. The second particle size is the particle size of the smallest precipitate in the above-mentioned upper n% of the precipitates having a large particle size in the structure of the heat-resistant member to be inspected. As a result, the selection criteria for whether or not the precipitate is to be calculated for the average particle size can be aligned between the heat-resistant material and the heat-resistant member to be inspected, so that the estimation is based on the state of the surface structure of the heat-resistant member to be inspected. The accuracy of estimating the operating temperature of the heat-resistant member to be inspected can be improved.

(5) In some embodiments, in any of the methods (1) to (4) above,
The precipitate in the structure of the heat-resistant material contains at least a first-class precipitate and a second-class precipitate of different types.
In the relationship acquisition step, the first relationship between the average particle size of the precipitate having the first particle size or more among the first-class precipitates and the parameters related to the operating temperature and the operating time of the heat-resistant material, and the second type. The second relationship between the average particle size of the precipitate having the first particle size or more and the parameters relating to the operating temperature and the operating time of the heat-resistant material is acquired.

According to the method (5) above, the relationship acquisition step acquires the first relationship and the second relationship, respectively, for the first-class precipitate and the second-class precipitate of different types. As a result, parameters related to the operating temperature of the heat-resistant member to be inspected are obtained in the operating temperature parameter acquisition step based on the first relationship for the first-class precipitates of different types and the second relationship for the second-class precipitates. Therefore, the accuracy of estimating the operating temperature of the heat-resistant member to be inspected can be further improved.
That is, by identifying the precipitates in the structure of the heat-resistant member to be inspected by, for example, using a scanning electron microscope, the first precipitate and the second precipitate in the structure of the heat-resistant member to be inspected in the average particle size acquisition step. The average particle size of the precipitate having a second particle size or higher can be determined by measurement. Then, in the operating temperature parameter acquisition step, the heat-resistant member to be inspected is used based on the average particle size of the first relationship acquired in the relationship acquisition step and the first precipitate obtained in the average particle size acquisition step. The first parameter related to temperature can be obtained, and the heat resistance of the inspection target is based on the second relationship acquired in the relationship acquisition step and the average particle size of the second precipitate obtained in the average particle size acquisition step. A second parameter relating to the operating temperature of the member can be obtained.
As a result, for example, the obtained first parameter and the second parameter are compared, and if there is no large difference between the values of the first parameter and the second parameter, the reliability of the values of the first parameter and the second parameter is high. Therefore, the accuracy of estimating the operating temperature of the heat-resistant member to be inspected is improved.
Further, the estimation accuracy is improved by estimating the operating temperature of the heat-resistant member to be inspected based on the parameter of the first parameter and the second parameter, which is considered to be more reliable.
As described above, according to the method (5) above, the operating temperature of the heat-resistant member to be inspected is based on the first relationship for the first-class precipitates of different types and the second relationship for the second-class precipitates. As described above, the accuracy of estimating the operating temperature of the heat-resistant member to be inspected can be further improved because the parameters related to each can be obtained.

(6) In some embodiments, in any of the methods (1) to (4) above,
The precipitate in the structure of the heat-resistant material contains at least a first-class precipitate and a second-class precipitate of different types.
The relationship acquisition step is a third of the average particle size of the first-class precipitate and the second-class precipitate having a particle size of the first particle size or higher and parameters relating to the operating temperature and the operating time of the heat-resistant material. Get a relationship.

According to the method (6) above, the relationship acquisition step does not distinguish between the first-class precipitate and the second-class precipitate of different types of the first-class precipitate and the second-class precipitate. To acquire the third relationship. As a result, it is possible to obtain the parameters related to the operating temperature of the heat-resistant member to be inspected in the operating temperature parameter acquisition step without distinguishing between the first-class precipitate and the second precipitate. The operating temperature of the heat-resistant member to be inspected can be easily estimated.
That is, for example, even if the structure of the heat-resistant member to be inspected cannot accurately distinguish between the first precipitate and the second precipitate, if it is known whether it is the first precipitate or the second precipitate. In the average particle size acquisition step, the average particle size of the first precipitate and the second precipitate in the structure of the heat-resistant member to be inspected can be determined by measurement. Then, in the operating temperature parameter acquisition step, the parameters related to the operating temperature of the heat-resistant member to be inspected are set based on the third relationship acquired in the relationship acquisition step and the above average particle size obtained in the average particle size acquisition step. You can ask.
By doing so, it is possible to obtain the parameters related to the operating temperature of the heat-resistant member to be inspected without distinguishing between the first-class precipitate and the second-class precipitate. As described above, the operating temperature of the heat-resistant member to be inspected can be easily estimated.

(7) In some embodiments, in any of the methods (1) to (6) above, the relationship acquisition step obtains the average particle size and the parameters used to acquire the relationship. If the standard error with the relationship is out of the permissible range, the first particle size is changed and the relationship is reacquired.

According to the method (7) above, when the standard error between the average particle size and parameters used to acquire the relationship and the acquired relationship is out of the permissible range, the relationship acquisition step is the first particle size. Since the above relationship is reacquired by changing the above, the standard error between the average particle size and parameters used for reacquiring the above relationship and the reacquired above relationship can be reduced, and by extension, the inspection target. The accuracy of estimating the operating temperature of the heat-resistant member can be further improved.

(8) In some embodiments, in any of the methods (1) to (7) above, the heat-resistant material and the heat-resistant member to be inspected are made of high-strength austenitic steel.

According to the method (8) above, even if the frequency of occurrence of new precipitates increases in the high-strength austenitic steel shortly after the start of use, among the precipitates, precipitates having a predetermined particle size or larger Since the operating temperature of the heat-resistant member can be estimated based on the average particle size, the estimation accuracy of the operating temperature can be improved.

(9) The method for inspecting a heat-resistant member according to at least one embodiment of the present invention is as follows.
Among the precipitates in the structure of the heat-resistant member to be inspected, the average grain size of the precipitate having a second particle size or more, which is the particle size corresponding to the first particle size of the precipitate in the structure of the heat-resistant material, is determined by measurement. Diameter acquisition process and
Among the precipitates in the structure of the heat-resistant material, the relationship between the average particle size of the precipitate having the first particle size or more and the parameters related to the operating temperature and the operating time of the heat-resistant material, and the average particle size acquisition step are obtained. The present invention includes an operating temperature parameter acquisition step of obtaining a parameter relating to the operating temperature of the heat-resistant member to be inspected based on the average particle size.

According to the method (9) above, among the precipitates in the structure of the heat-resistant member to be inspected, the average particle size of the precipitates having the second particle size or more, which is the particle size corresponding to the first particle size, is determined by measurement. A particle size acquisition step is provided. Therefore, the influence of the precipitate having a particle size smaller than the second particle size, which is the particle size corresponding to the first particle size, can be excluded from the average particle size of the precipitate in the structure of the heat-resistant member to be inspected, which is obtained in the average particle size acquisition step. ..
Then, according to the method (9 ) above, the relationship between the average particle size of the precipitates having the first particle size or more in the structure of the heat-resistant material and the parameters related to the operating temperature and the operating time of the heat-resistant material, and The present invention includes an operating temperature parameter acquisition step of obtaining a parameter relating to the operating temperature of the heat-resistant member to be inspected based on the average particle diameter obtained in the average particle size acquisition step. As a result, the parameters related to the operating temperature of the heat-resistant member to be inspected can be obtained in a state where the influence of precipitates having a predetermined particle size is excluded, so that the estimation accuracy of the operating temperature of the heat-resistant member to be inspected can be improved.

(10) In some embodiments, in the method of (9) above, precipitates having the first particle size or more among the precipitates in the structure of the heat-resistant material from a plurality of standard samples having different heating temperatures and heating times. Further includes a relationship acquisition step for acquiring the relationship between the average particle size of the heat-resistant material and the parameters relating to the operating temperature and the operating time of the heat-resistant material.

According to the method (10) above, the relationship between the average particle size of the precipitates having the first particle size or more in the structure of the heat-resistant material and the parameters related to the operating temperature and the operating time of the heat-resistant material is obtained. In the above-mentioned relationship obtained, the influence of precipitates having a particle size smaller than the first particle size can be eliminated. As a result, in the above-mentioned acquired relationship, the influence of newly generated precipitates and the influence of the precipitates disappearing with the passage of time can be suppressed, so that the above-mentioned acquired relationship is suitable for estimating the operating temperature. It becomes a thing.

(11) In some embodiments, in any of the methods (1) to (10) above,
Prior to the average particle size acquisition step, a hardness measuring step of measuring the hardness of the heat-resistant member to be inspected, and a hardness measuring step.
The operating temperature of the heat-resistant member to be inspected is estimated by inputting the hardness of the heat-resistant member to be inspected obtained in the hardness measuring step into the correlation between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material. Further equipped with an operating temperature estimation process,
Whether or not the average particle size acquisition step is to be performed is determined based on the working temperature of the heat-resistant member to be inspected estimated in the working temperature estimation step.

According to the method (11) above, the operating temperature of the heat-resistant member to be inspected is estimated by a simple method of measuring the hardness of the heat-resistant member to be inspected, and a more detailed operating temperature is estimated based on the estimated operating temperature. The average particle size acquisition step can be carried out when it is determined that the estimation is necessary. As a result, it is possible to shorten the time for estimating the operating temperature of the heat-resistant member to be inspected and improve the accuracy of estimating the operating temperature of the heat-resistant member to be inspected.

(12) In some embodiments, in the method (11) above, a step of obtaining a correlation between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material from a plurality of samples having different heating temperatures and heating times is performed. Further prepare.

According to the method (12) above, the correlation between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material can be obtained.

(13) In some embodiments, in the method (11) or (12) above, the correlation is based on information about the hardness of the heat-resistant material, the operating temperature of the heat-resistant material, and the usage time of the heat-resistant material. It is a relationship between the hardness of the heat-resistant material extracted by the use time of the heat-resistant member to be inspected and the operating temperature of the heat-resistant material.

According to the method (13) above, the operating temperature of the heat-resistant member to be inspected can be immediately estimated from the hardness of the heat-resistant member to be inspected obtained by measurement and the above correlation.

(14) In some embodiments, in the method (11) or (12) above, the correlation is based on information about the hardness of the heat-resistant material, the operating temperature of the heat-resistant material, and the usage time of the heat-resistant material. It is a relationship between the obtained hardness of the heat-resistant material and parameters relating to the operating temperature and the operating time of the heat-resistant material.

According to the method (14) above, since the parameters related to the operating temperature and the operating time of the heat-resistant material are used, when the operating time of the heat-resistant member to be inspected is longer than the heating time of the sample prepared to obtain the above correlation. Even so, the operating temperature of the heat-resistant member to be inspected can be estimated.

According to at least one embodiment of the present invention, the operating temperature of the steel material can be accurately estimated based on the state of the structure of the surface of the steel material.

It is a figure which shows the schematic structure of the boiler. It is a flowchart which shows the schematic procedure of the inspection method of the heat-resistant member which concerns on some Embodiments. It is a flowchart which shows an example of the schematic procedure of a relation acquisition process. It is a graph which shows an example of the master curve in one Embodiment. This is an example of an image obtained by observing the surface of a standard sample of austenitic stainless steel with a scanning electron microscope. It is a figure which shows an example of the TTP diagram of austenitic stainless steel. It is a flowchart which shows an example of the procedure in a master curve acquisition process. It is a flowchart which shows an example of the detailed acquisition procedure of a master curve. It is a flowchart which shows an example of the schematic procedure of the average particle diameter acquisition process. It is a flowchart which shows an example of the procedure of the operating temperature parameter acquisition process. It is a flowchart which shows the schematic procedure of the inspection method of the heat-resistant member which concerns on other embodiment. It is a flowchart which shows the process in the working temperature estimation process based on hardness. It is a flowchart which shows the process in a correlation acquisition process. It is a figure which shows an example of the master data acquired in the master data acquisition process. It is a figure which shows the example of the master curve which shows the relationship between the hardness of a heat-resistant material and the operating temperature of a heat-resistant material, and (a) is the hardness of a heat-resistant material extracted in the use time of 10,000 hours, and the operating temperature of a heat-resistant material. (B) is an example of a master curve showing the relationship between the hardness of the heat-resistant material extracted after a usage time of 80,000 hours and the operating temperature of the heat-resistant material. It is a flowchart which shows an example of the schematic procedure of a hardness measurement process. It is a figure which shows the example of the master curve which shows the relationship between the hardness of a heat-resistant material and the parameter about the use temperature and use time of a heat-resistant material.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. Absent.
For example, expressions that represent relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a state of relative displacement with tolerances or angles and distances to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, 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, an expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also an uneven portion or chamfering within a range in which the same effect can be obtained. The shape including the part and the like shall also be represented.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions that exclude the existence of other components.

FIG. 1 is a diagram showing a schematic configuration of the boiler 10.
The boiler 10 has a combustion furnace 12 and a flue 14 connected to the upper part of the combustion furnace 12.
The furnace wall 16 of the combustion furnace 12 includes evaporation pipe for heating water in the upper part of the combustion furnace 12, a superheater 18 to superheat the steam are arranged. An economizer 20 for preheating water is arranged in the lower part of the flue 14. Further, a reheater 22 for reheating steam is arranged in the upper part of the flue 14.

A burner 24 is attached to the combustion furnace 12, and pulverized coal and air as fuel are supplied to the burner 24. The high-temperature exhaust gas generated by the combustion of the pulverized coal ejected from the burner 24 rises in the combustion furnace 12 and flows into the flue 14. The heat generated by the combustion is transferred to the evaporation pipe of the furnace wall 16, thereby heating the water. The heat of the exhaust gas is used for superheating steam in the superheater 18, reheating steam in the reheater 22, and preheating water in the economizer 20. The low-temperature exhaust gas flows into, for example, a denitration device provided downstream of the boiler 10 and is purified.
The steam (main steam) superheated by the superheater 18 is supplied to the steam turbine 26, for example, and is used for power generation or the like.

FIG. 2 is a flowchart showing a schematic procedure of an inspection method for heat-resistant members according to some embodiments.
The heat-resistant member to be inspected is, for example, a steel pipe constituting the superheater 18 and the reheater 22.

As shown in FIG. 2, the method for inspecting the heat-resistant member includes a relationship acquisition step S10, an average particle size acquisition step S20, and an operating temperature parameter acquisition step S30.
In the relationship acquisition step S10, the relationship between the average particle size of the precipitates having the first particle size or more in the structure of the heat-resistant material and the parameters related to the operating temperature and the operating time of the heat-resistant material is acquired.

In the average particle size acquisition step S20, among the precipitates in the structure of the heat-resistant member to be inspected, the average particle size of the precipitates having the second particle size or more, which is the particle size corresponding to the first particle size, is determined by measurement.
In the operating temperature parameter acquisition step S30, the inspection target is based on the above relationship acquired in the relationship acquisition step S10, the average particle diameter obtained in the average particle size acquisition step S20, and the usage time of the heat-resistant member to be inspected. Parameters related to the operating temperature of the heat-resistant member are required.
The particle size in some embodiments described below may be any of those according to various definitions such as a major axis, a minor axis, a biaxial average diameter, and a circle equivalent diameter. For convenience of explanation, regardless of which of the above definitions the particle size conforms to, it is simply referred to as a particle size in the following description.

(Relationship acquisition process S10)
Hereinafter, the relationship acquisition step S10 according to some embodiments will be described with reference to FIG. FIG. 3 is a flowchart showing an example of a schematic procedure of the relationship acquisition step S10.
In the relationship acquisition step S10, according to each of the steps S101 to S110 described below, the average particle size of the precipitate having the first particle size or more among the precipitates in the structure of the heat-resistant material, and the parameters relating to the operating temperature and the operating time of the heat-resistant material. The relationship with is acquired as a master curve which is a correlation diagram between the average particle size and the parameter.
That is, in some embodiments, the master curve is a parameter (temperature / time parameter) relating to the average particle size of the precipitate having the first particle size or more among the precipitates in the structure of the heat-resistant material, and the operating temperature and operating time of the heat-resistant material. ) It is a correlation diagram with λ, and is a graph as shown in FIG. 4, for example. Note that FIG. 4 is a graph showing an example of a master curve according to some embodiments. As shown in FIG. 4, in the master curve C, for example, when the temperature / time parameter λ is taken on the horizontal axis and the average particle size of the precipitate is taken on the vertical axis, the relationship between the average particle size and the temperature / time parameter λ is taken. It is represented as a curve showing.

Here, the temperature / time parameter λ is, for example, a Larson mirror parameter, where the temperature (sample temperature) when the sample is heated is T (unit: K), and the heating time is t (unit: h). And when the material constant of the sample is C, it is expressed by the following equation (1).
λ = T × (C + log (t)) / 1000 ... (1)

The heat-resistant material refers to a material having the same or similar composition as the heat-resistant member to be inspected. The shape of the heat-resistant material does not have to be the same as that of the heat-resistant member to be inspected. That is, the heat resistant material is a standard sample. In one embodiment, the heat resistant material and the heat resistant member to be inspected are, for example, high-strength austenitic steel.

Here, the reason for calculating the average particle size of the precipitate having the first particle size or higher when calculating the average particle size of the precipitate in the structure of the heat-resistant material will be described.
The above relationship calculated in the relationship acquisition step S10, that is, the master curve, is data to be referred to when obtaining a parameter relating to the operating temperature of the heat-resistant member to be inspected in the operating temperature parameter acquisition step S30 described later. Although detailed description will be given later, in the operating temperature parameter acquisition step S30, the temperature / time parameters corresponding to the average particle size of the precipitate in the structure of the heat-resistant member to be inspected obtained in the average particle size acquisition step S20 are obtained. It is read from the master curve calculated in the relationship acquisition step S10, and the operating temperature of the heat-resistant member to be inspected is estimated based on the read temperature / time parameters.
Therefore, if the rate of change of the average particle size with respect to the value of the temperature / time parameter in the master curve is small, the reading accuracy when reading the value of the temperature / time parameter corresponding to the average particle size from the master curve becomes low, and the inspection target The estimation accuracy of the operating temperature of the heat-resistant member may also be low.

Generally, in a heat-resistant material or a heat-resistant member to be inspected, a precipitate that becomes coarser with the passage of time and a precipitate that becomes smaller and disappears at a certain time when placed in a high temperature environment are present together. There is. Therefore, there is a period in which no clear change is observed in the average particle size of the precipitate with the passage of time. Therefore, when the average particle size of the precipitate including the precipitate that is miniaturized and disappears is calculated and the above-mentioned master curve is acquired, the average particle size changes within the range of the temperature / time parameter values corresponding to the period. Since the rate is small, when this master curve is used, the accuracy of estimating the operating temperature of the heat-resistant member to be inspected may be low as described above.

Therefore, in some embodiments, when calculating the average particle size of the precipitate in the structure of the heat-resistant material, in order to suppress the influence of the precipitate that becomes smaller and disappears as described above, the precipitate having the first particle size or more is deposited. The average particle size of the object is to be calculated. In one embodiment described below, the first particle size is n micrometers. Here, the value of n is appropriately determined in consideration of the composition of the heat-resistant material, the type of precipitate, the standard error in the regression analysis at the time of calculating the master curve, and the like, which will be described later.

As described above, in the relationship acquisition step S10 of one embodiment, the relationship between the average particle size of the precipitates having the first particle size or more in the structure of the heat-resistant material and the parameters related to the operating temperature and the operating time of the heat-resistant material is determined. To be acquired. Therefore, in the acquired relationship, that is, in the master curve, the influence of precipitates having a particle size smaller than the first particle size can be eliminated. As a result, the influence of newly generated precipitates and the influence of precipitates that disappear with the passage of time can be suppressed in the acquired master curve, so that the acquired master curve is suitable for estimating the operating temperature. Become.

In the relationship acquisition step S10, first, the standard sample is prepared in the standard sample preparation step S101. In the standard sample preparation step S101, a plurality of standard samples having different heating temperatures and heating times are prepared.
Such a plurality of standard samples can be obtained, for example, by preparing a plurality of untreated samples and subjecting these samples to heat treatment (aging treatment) at different temperatures. In addition, such a plurality of standard samples can also be obtained by performing a creep strength test on a plurality of untreated samples and stopping the creep strength test for each sample at different times.

In the structure observation step S103, the structure of a plurality of standard samples prepared in the standard sample preparation step S101 is observed. For the tissue observation, for example, a scanning electron microscope is used, but an optical microscope may be used.

In the precipitate identification step S105, the precipitate of the standard sample whose structure was observed in the tissue observation step S103 is identified. If a scanning electron microscope is used for tissue observation in the tissue observation step S103, the precipitate can also be identified by the scanning electron microscope.

FIG. 5 is an example of an image obtained by observing the surface of a standard sample of austenitic stainless steel with a scanning electron microscope. In the example shown in FIG. 5, for example, Z phase, σ phase, M ₂₃ C ₆ and Cu are recognized as precipitates.

In the TTP diagram creating step S107, a TTP (Time-Temperature-Prescription) diagram is created, and in the particle size distribution acquisition step S109, the particle size distribution of the type of precipitate to be created for the master curve is acquired.
In the TTP diagram creating step S107, a TTP diagram is created based on the result of the tissue observation in the tissue observation step S103 and the result of the precipitate identification in the precipitate identification step S105.

FIG. 6 shows an example of a TTP diagram of austenitic stainless steel. The region α in FIG. 6 is a region in which the type of precipitate for which the master curve is to be created does not exist. The region β is a region in which one type of precipitate (type 1 precipitate) exists among the types of precipitates for which the master curve is to be created. The region γ is a region in which two types of precipitates (type 1 precipitate and type 2 precipitate) are present among the types of precipitates for which the master curve is to be created.
For example, in the case of austenitic stainless steel shown in FIG. 5 as an example of a microstructure image, the Z phase is a type 1 precipitate and the σ phase is a type 2 precipitate, as will be described later. In the image of FIG. 5, the Z phase, that is, the type 1 precipitate and the σ phase, that is, the type 2 precipitate are recognized. Therefore, the image of FIG. 5 was subjected to the heat treatment corresponding to the region γ in FIG. Corresponds to the image of a standard sample.

In the particle size distribution acquisition step S109, the particle size distribution of the type of precipitate to be created for the master curve is acquired. Specifically, for example, from an observation image as shown in FIG. 5, an image of a precipitate of a type for which a master curve is to be created is extracted by a known image processing based on the gradation of the image. That is, since the gradation of the image of the precipitate in the observation image differs depending on the type of the precipitate, it is easy to extract the type of precipitate to be created for the master curve by a known image processing method.
Then, each particle size of the extracted image is measured by a known image processing, and the particle size distribution is obtained for each type of precipitate based on the measured particle size.

In the master curve acquisition step S110, the master curve is acquired based on the particle size distribution information acquired in the particle size distribution acquisition step S109.

FIG. 7 is a flowchart showing an example of the procedure in the master curve acquisition step S110 shown in FIG. In some embodiments, in step S111, a master curve for the precipitate of region β in the TTP diagram created in the TTP diagram creating step S107 of FIG. 3, that is, the type 1 precipitate is acquired. The detailed acquisition procedure of the master curve will be described in detail later with reference to FIG.

Next, in step S113, it is determined whether or not the region γ exists in the TTP diagram created in the TTP diagram creating step S107 of FIG.

If the region γ does not exist, there is no other master curve to be acquired, so the master curve acquisition process is terminated.

When the region γ is present, in step S115, the first type precipitation in the region γ is based on the result of the tissue observation in the structure observation step S103 of FIG. 3 and the result of the precipitation identification in the precipitate identification step S105. The coarsening rate S1 of the substance and the coarsening rate S2 of the second-class precipitate are confirmed.

As the coarsening rate becomes smaller, the rate of change of the average particle size with respect to the values of the temperature / time parameters becomes smaller in the calculated master curve. If the rate of change becomes small, as described above, the reading accuracy when reading the temperature / time parameters corresponding to the average particle size from the master curve becomes low, and the estimation accuracy of the operating temperature of the heat-resistant member to be inspected may also become low. There is.

Therefore, the master curve to be acquired is determined according to the magnitude of the coarsening speed as follows.
For example, the coarsening rate S1 is large and the operating temperature of the heat-resistant member to be inspected can be accurately estimated from the master curve related to the type 1 precipitate, but the coarsening rate S2 is small and the master curve related to the type 2 precipitate. If it is considered that the operating temperature of the heat-resistant member to be inspected cannot be estimated accurately (S1 >> S2), the process proceeds to step S121. In step S121, the first master curve for the first-class precipitate of region γ in the TTP diagram is acquired.

The coarsening rate S1 is large and the operating temperature of the heat-resistant member to be inspected can be accurately estimated from the master curve related to the type 1 precipitate, but the coarsening rate S2 is small and the master curve related to the type 2 precipitate. Therefore, if it is considered that the operating temperature of the heat-resistant member to be inspected cannot be estimated accurately (S1 >> S2), there is no other type of precipitate in the region γ for which the master curve should be acquired. finish.

Further, for example, the coarsening rate S2 is large and the operating temperature of the heat-resistant member to be inspected can be accurately estimated from the master curve related to the type 2 precipitate, but the coarsening rate S1 is small and the master related to the type 1 precipitate. If it is considered that the operating temperature of the heat-resistant member to be inspected cannot be accurately estimated from the curve (S1 << S2), the process proceeds to step S123. In step S123, the second master curve for the second-class precipitate of region γ in the TTP diagram is acquired.

The coarsening rate S2 is large and the operating temperature of the heat-resistant member to be inspected can be accurately estimated from the master curve related to the type 2 precipitate, but the coarsening rate S1 is small and the master curve related to the type 1 precipitate. Therefore, when it is considered that the operating temperature of the heat-resistant member to be inspected cannot be estimated accurately (S1 << S2), since there is no other type of precipitate for which the master curve should be acquired in the region γ, the master curve acquisition step is performed. finish.

Further, for example, the coarsening speeds S1 and S2 are both large, and it is considered that the operating temperature of the heat-resistant member to be inspected can be estimated accurately from the master curve related to the type 1 precipitate and the master curve related to the type 2 precipitate. If so, the process proceeds to step S125. In step S125, the first master curve for the first-class precipitate of the region γ in the TTP diagram is acquired, and the second master curve for the second-class precipitate of the region γ in the TTP diagram is acquired to master. The curve acquisition process is completed.

FIG. 8 is a flowchart showing an example of a detailed acquisition procedure of the master curve. The procedure shown in the flowchart of FIG. 8 is a specific procedure in step S111, step S121, step S123, and step S125 of FIG.

In some embodiments, in step S151, with respect to the type of precipitate for which the master curve is to be created, the first particle size or higher is based on the particle size distribution information acquired in the particle size distribution acquisition step S109 of FIG. Extract the precipitate.
When step S151 is carried out as a part of the process in step S111 of FIG. 7, for each of the standard samples belonging to the region β in the TTP diagram, the precipitate of the region β, that is, the type 1 precipitate. Of these, precipitates having a first particle size or larger are extracted.
Similarly, when step S151 is carried out as part of the process in step S121 of FIG. 7, for each of the standard samples belonging to region γ in the TTP diagram, the first of the first-class precipitates of region γ Extract precipitates larger than the particle size.
Further, when step S151 is carried out as a part of the process in step S123 of FIG. 7, for each of the standard samples belonging to the region γ in the TTP diagram, the first grain of the second type precipitate of the region γ Extract precipitates larger than the diameter.
When step S151 is carried out as part of the process in step S125 of FIG. 7, for each of the standard samples belonging to the region γ in the TTP diagram, the first particle size or more of the first-class precipitates of the region γ Is extracted, and among the second-class precipitates in the region γ, the precipitates having the first particle size or larger are extracted.

In step S153, the average particle size of the precipitate having the first particle size or more extracted in step S151 is calculated, and the calculated average particle size is arranged by the temperature / time parameters.
That is, by associating the temperature / time parameter λ of the standard sample with each of the calculated average particle diameters, a plurality of data represented by the average particle diameter and the temperature / time parameter λ are generated.

In step S155, based on the plurality of data generated in step S153, a graph with the temperature / time parameter λ on the horizontal axis and the average particle size on the vertical axis is created, and regression analysis is performed to obtain a regression curve. Calculate the standard error.
When step S155 is carried out as a part of the process in step S125 of FIG. 7, the temperature is shown on the horizontal axis on the horizontal axis based on the plurality of data related to the type 1 precipitate among the plurality of data generated in step S153. -Take the time parameter λ, create a graph with the average particle size on the vertical axis, perform regression analysis, and calculate the regression curve and standard error. Similarly, among the plurality of data generated in step S153, a graph in which the temperature / time parameter λ is set on the horizontal axis and the average particle size is taken on the vertical axis based on the plurality of data related to the type 2 precipitate. And perform regression analysis to calculate the regression curve and standard error.

In step S157, it is determined whether or not the standard error calculated in step S155 is within a predetermined allowable range.
If the affirmative determination is made in step S157, the regression curve calculated in step S155 is adopted as the master curve in step S159.
When step S159 is carried out as a part of the process in step S125 of FIG. 7, among the regression curves calculated in step S155, the regression curve related to the type 1 precipitate is adopted as the first master curve, and the second The regression curve related to the seed precipitate is adopted as the second master curve.

If the negative determination in step S157 is made, the first particle size is changed in step S161. After that, the process returns to step S151, and the above-described processing is executed again.

As described above, in one embodiment, it is used to obtain the relationship between the average particle size of the precipitates having the first particle size or more in the structure of the heat-resistant material and the parameters related to the operating temperature and the operating time of the heat-resistant material. If the standard error between the average particle size and the temperature / time parameter λ and the acquired relationship is out of the permissible range, the first particle size is changed and the relationship is reacquired. As a result, the standard error between the average particle size and temperature / time parameter λ used to reacquire the above relationship and the reacquired above relationship can be reduced, and by extension, the operating temperature of the heat-resistant member to be inspected. The estimation accuracy of can be further improved.

(Average particle size acquisition step S20)
Hereinafter, the average particle size acquisition step S20 will be described. FIG. 9 is a flowchart showing an example of a schematic procedure of the average particle size acquisition step S20.
In some embodiments, the heat-resistant member to be inspected is acquired in the inspection target acquisition step S201. For example, if the heat-resistant member to be inspected is a steel pipe constituting the superheater 18 or the reheater 22 of the boiler 10, the heat-resistant member to be inspected is heat-resistant by cutting a part of the steel pipe when the periodic inspection of the boiler 10 is suspended. Acquire a member. When it is difficult to obtain the heat-resistant member to be inspected, for example, a replica of the surface of the heat-resistant member to be inspected is obtained by the replica method. The following description mainly describes the case where the heat-resistant member to be inspected can be obtained.

In the structure observation step S203, the structure of the heat-resistant member to be inspected acquired in the inspection target acquisition step S201 is observed. For the tissue observation, for example, a scanning electron microscope is used, but an optical microscope may be used.

In the precipitate identification step S205, the precipitate of the heat-resistant member to be inspected for which the structure was observed in the structure observation step S203 is identified. If a scanning electron microscope is used for tissue observation in the tissue observation step S203, the precipitate can also be identified by the scanning electron microscope.

The region determination step S207 and the particle size distribution acquisition step S209 are carried out.
In the region determination step S207, with reference to the TTP diagram created in the TTP diagram creation step S107 of FIG. 3, the inspection performed by observing the structure in the tissue observation step S203 based on the precipitate identification result in the precipitate identification step S205. It is determined in which region of the TTP diagram the structure of the target heat-resistant member is.

In the particle size distribution acquisition step S209, among the precipitates of the heat-resistant member to be inspected for which the structure was observed in the structure observation step S203, the same as the precipitate of the type for which the master curve was created in the relationship acquisition step S10 of FIG. Obtain the particle size distribution of different types of precipitates. For the acquisition of the particle size distribution, for example, the same method as in the particle size distribution acquisition step S109 of FIG. 3 can be used.

In the average particle size calculation step S211, based on the particle size distribution information acquired in the particle size distribution acquisition step S209, precipitates having a particle size of the second particle size or more, which is the particle size corresponding to the first particle size, are selected for each type of precipitate. Each is extracted and the average particle size is calculated respectively. The second particle size in one embodiment is the same as the first particle size of the precipitate related to the master curve acquired in the relationship acquisition step S10. That is, in one embodiment, for example, if the first particle size of the first-class precipitate related to the master curve for the region β acquired in the relationship acquisition step S10 is n micrometers, it relates to the heat-resistant member to be inspected. The second particle size of the first-class precipitate of region β is also n micrometer.

As described above, in the average particle size acquisition step S20 of one embodiment, among the precipitates in the structure of the heat-resistant member to be inspected, the average particles of the precipitates having the second particle size or more, which is the particle size corresponding to the first particle size. Determine the diameter by measurement. Therefore, the influence of the precipitate having a particle size smaller than the second particle size, which is the particle size corresponding to the first particle size, is excluded from the average particle size of the precipitate in the structure of the heat-resistant member to be inspected obtained in the average particle size acquisition step S20. it can.
Further, in one embodiment, the first particle size and the second particle size are both n micrometers. As a result, the selection criteria for whether or not the precipitate is to be calculated for the average particle size can be aligned between the heat-resistant material and the heat-resistant member to be inspected, so that the estimation is based on the state of the surface structure of the heat-resistant member to be inspected. The accuracy of estimating the operating temperature of the heat-resistant member to be inspected can be improved.

(Operating temperature parameter acquisition step S30)
Hereinafter, the operating temperature parameter acquisition step S30 will be described. FIG. 10 is a flowchart showing an example of the procedure of the operating temperature parameter acquisition step S30.

In some embodiments, in step S301, the next process is determined depending on the determination result in the region determination step S207 of FIG. 9, that is, which region the structure of the heat-resistant member to be inspected is.
For example, when it is determined in the region determination step S207 of FIG. 9 that the structure of the heat-resistant member to be inspected is the structure of the region α, the operating temperature is estimated for the structure of the heat-resistant member to be inspected based on the master curve. The necessary precipitate is not present. In this case, after performing the determination process in step S301, the operating temperature parameter acquisition step S30 is terminated.

Further, for example, when it is determined in the region determination step S207 of FIG. 9 that the structure of the heat-resistant member to be inspected is the structure of the region β, the process proceeds to step S303. In step S303, from the master curve relating to the first-class precipitate for the region β acquired in step S111 of FIG. 7, the first-class precipitate having the second or higher particle size calculated in the average particle size calculation step S211 of FIG. 9 Acquire the temperature / time parameter λ corresponding to the average particle size. Then, by substituting the acquired temperature / time parameter λ and the usage time of the heat-resistant member to be inspected into the above-mentioned equation (1), an estimated value of the operating temperature of the heat-resistant member to be inspected is acquired.

Further, for example, when it is determined in the region determination step S207 of FIG. 9 that the structure of the heat-resistant member to be inspected is the structure of the region γ, the process proceeds to step S305, and the operating temperature of the heat-resistant member to be inspected is as follows. Get an estimate of.
For example, when only the average particle size of the first-class precipitate in the region γ was obtained in the average particle size calculation step S211 of FIG. 9, in step S305, it was obtained in either step S121 or step S125 of FIG. From the first master curve of the first-class precipitate in the region γ, the temperature / time parameter λ corresponding to the average grain size of the first-class precipitate calculated in the average particle size calculation step S211 of FIG. 9 is acquired. Then, by substituting the acquired temperature / time parameter λ and the usage time of the heat-resistant member to be inspected into the above-mentioned equation (1), an estimated value of the operating temperature of the heat-resistant member to be inspected is acquired.

Further, for example, when only the average particle size of the second type precipitate of the region γ is obtained in the average particle size calculation step S211 of FIG. 9, in step S305, in either step S123 or step S125 of FIG. From the second master curve of the second type precipitate of the obtained region γ, the temperature / time parameter λ corresponding to the average particle size of the second type precipitate calculated in the average particle size calculation step S211 of FIG. 9 is acquired. .. Then, by substituting the acquired temperature / time parameter λ and the usage time of the heat-resistant member to be inspected into the above-mentioned equation (1), an estimated value of the operating temperature of the heat-resistant member to be inspected is acquired.

Further, for example, when both the average particle size of the first-class precipitate and the average particle size of the second-class precipitate in the region γ are obtained in the average particle size calculation step S211 of FIG. 9, in step S305, FIG. Temperature and time corresponding to the average particle size of the first-class precipitate calculated in the average particle size calculation step S211 of FIG. 9 from the first master curve of the first-class precipitate of the region γ obtained in step S125 of 7. The first parameter λ1, which is the parameter λ, is acquired. Then, by substituting the acquired first parameter λ1 and the usage time of the heat-resistant member to be inspected into the above-mentioned equation (1), the first estimated value of the operating temperature of the heat-resistant member to be inspected is acquired.
Similarly, in step S305, the average of the type 2 precipitates calculated in the average particle size calculation step S211 of FIG. 9 from the second master curve of the type 2 precipitates of the region γ obtained in step S125 of FIG. The second parameter λ2, which is the temperature / time parameter λ corresponding to the particle size, is acquired. Then, by substituting the acquired second parameter λ2 and the usage time of the heat-resistant member to be inspected into the above-mentioned equation (1), the second estimated value of the operating temperature of the heat-resistant member to be inspected is acquired.

In one embodiment, when the first estimated value and the second estimated value of the operating temperature of the heat-resistant member to be inspected are obtained in this way, for example, the estimation accuracy of the first estimated value and the second estimated value is obtained. The estimated value of the one with the highest value is adopted as the estimated value of the operating temperature of the heat-resistant member to be inspected. When the first estimated value and the second estimated value of the operating temperature of the heat-resistant member to be inspected are obtained in this way, for example, the average value of the first estimated value and the second estimated value is the heat resistance of the inspection target. It may be adopted as an estimated value of the operating temperature of the member.

The first parameter λ1 and the second parameter λ2 obtained as described above are compared, and if there is no large difference between the values of the first parameter λ1 and the second parameter λ2, the first parameter λ1 and the second parameter λ2 Since it can be determined that the value of is highly reliable, the accuracy of estimating the operating temperature of the heat-resistant member to be inspected is improved.
As described above, according to some embodiments, with respect to the first-class precipitate and the second-class precipitate of different types, the first master curve, which is the first relationship of the first-class precipitate, and the second-class precipitate. Since the parameters related to the operating temperature of the heat-resistant member to be inspected can be obtained based on the second master curve, which is the second relationship for the precipitate, the operating temperature of the heat-resistant member to be inspected is estimated as described above. The accuracy can be further improved.

As described above, in the operating temperature parameter acquisition step S30 of some embodiments, the heat resistance of the inspection target is based on the relationship acquired in the relationship acquisition step S10 and the average particle size obtained in the average particle size acquisition step S20. Obtain the parameters related to the operating temperature of the member. As a result, the parameters related to the operating temperature of the heat-resistant member to be inspected can be obtained in a state where the influence of precipitates having a predetermined particle size is excluded, so that the estimation accuracy of the operating temperature of the heat-resistant member to be inspected can be improved.

As described above, in some embodiments, even if the frequency of occurrence of new precipitates increases in the high-strength austenitic steel shortly after the start of use, the precipitates having a predetermined particle size or more are precipitated. Since the operating temperature of the heat-resistant member can be estimated based on the average particle size of the object, the estimation accuracy of the operating temperature can be improved.

Hereinafter, other embodiments will be described. In some of the above-described embodiments, in step S125 in the master curve acquisition step S110 shown in FIG. 7, a first master curve for the first-class precipitate and a second master curve for the second-class precipitate were acquired. .. That is, the type 1 precipitate and the type 2 precipitate were distinguished, and a master curve was obtained for each precipitate.
In another embodiment, the third master curve is acquired without distinguishing between the first-class precipitate and the second-class precipitate as follows.

That is, in another embodiment, in step S155 of FIG. 8, whether the plurality of data generated in the plurality of data generated in step S153 are the data related to the first-class precipitate or the second-class precipitate. Regression analysis is performed to calculate the regression curve and standard error without distinguishing whether it is data or not.

Then, in step S157, it is determined whether or not the standard error calculated in step S155 is within a predetermined allowable range.
If the affirmative determination is made in step S157, the regression curve calculated in step S155 is adopted as the third master curve in step S159.

If the negative determination in step S157 is made, the first particle size is changed in step S161. After that, the process returns to step S151, and the above-described processing is executed again.
By doing so, in the relationship acquisition step S10, the first grain of the first-class precipitate and the second-class precipitate is not distinguished whether it is the first-class precipitate or the second-class precipitate. The third master curve, which is the third relationship between the average particle size of the precipitate having a diameter or more and the parameters related to the operating temperature and the operating time of the heat-resistant material, can be obtained.

As a result, it becomes possible to obtain the parameters related to the operating temperature of the heat-resistant member to be inspected in the operating temperature parameter acquisition step S30 without distinguishing between the first-class precipitate and the second precipitate. , The operating temperature of the heat-resistant member to be inspected can be easily estimated.

That is, for example, even if the structure of the heat-resistant member to be inspected cannot accurately distinguish between the first precipitate and the second precipitate, if it is known whether it is the first precipitate or the second precipitate. In the average particle size acquisition step S20, the average particle size of the first precipitate and the second precipitate in the structure of the heat-resistant member to be inspected can be determined by measurement. Then, in the operating temperature parameter acquisition step S30, the heat-resistant member to be inspected is used based on the third master curve acquired in the relationship acquisition step S10 and the above average particle size obtained in the average particle size acquisition step S20. Parameters related to temperature can be obtained.

By doing so, it becomes possible to obtain the parameters related to the operating temperature of the heat-resistant member to be inspected without distinguishing between the first-class precipitate and the second-class precipitate. The operating temperature of the heat-resistant member can be easily estimated.

Hereinafter, other embodiments will be described. In some of the above-described embodiments, the first particle size and the second particle size are both n micrometers, which are the same particle size. In another embodiment described below, the first particle size is the particle size of the nth precipitate in order from the precipitate having the largest diameter among the precipitates in the structure of the heat-resistant material, and the second particle size is It is the particle size of the nth precipitate in order from the precipitate having the largest diameter among the precipitates in the structure of the heat-resistant member to be inspected.

As a result, the first particle size and the second particle size can be brought close to each other, so that the selection criteria for whether or not the precipitate is to be calculated for the average particle size are aligned between the heat-resistant material and the heat-resistant member to be inspected. Be done. Therefore, it is possible to improve the estimation accuracy of the operating temperature of the heat-resistant member to be inspected, which is estimated based on the state of the surface structure of the heat-resistant member to be inspected.
In addition, if the size of the region where the precipitate is investigated to calculate the average particle size is approximately the same for the heat-resistant material and the heat-resistant member to be inspected, the precipitate used for calculating the average particle size is selected. In order to do so, n precipitates may be selected in order from the precipitate having the maximum diameter, so that the precipitate used for calculating the average particle size can be easily selected. Therefore, it is possible to improve the work efficiency when investigating the precipitates in order to calculate the average particle size.

Hereinafter, other embodiments will be described. In some of the above-described embodiments, the first particle size and the second particle size are both n micrometers, which are the same particle size. In another embodiment described below, the first particle size is the particle size of the smallest precipitate in the precipitates contained in the top n% of the precipitates having a large particle size in the structure of the heat-resistant material. The second particle size is the particle size of the smallest precipitate in the above-mentioned upper n% of the precipitates having a large particle size in the structure of the heat-resistant member to be inspected.

As a result, the selection criteria for whether or not the precipitate is to be calculated for the average particle size can be aligned between the heat-resistant material and the heat-resistant member to be inspected, so that the estimation is based on the state of the surface structure of the heat-resistant member to be inspected. The accuracy of estimating the operating temperature of the heat-resistant member to be inspected can be improved.
Further, by setting the selection criterion of the precipitate to be the calculation target of the average particle size to the particle size of the smallest precipitate among the precipitates contained in the number of the top n% having a large particle size, the average particle size can be calculated. The selection criteria for the precipitates can be set as the ratio to the total precipitates.

Hereinafter, other embodiments will be described. In some of the above-described embodiments, in the inspection target acquisition step S201 in the average particle size acquisition step S20, the heat-resistant member to be inspected is acquired, or the surface replica of the heat-resistant member to be inspected is acquired.
However, since it takes time for the extubation work and the replica collection work, it is difficult to extubate and collect the replica at many places during the suspension of periodic inspection of the boiler 10.
Therefore, in another embodiment described below, in order to narrow down the places where the extubation work and the replica collection work are performed, the operating temperature of the heat-resistant member to be inspected is simply estimated prior to the average particle size acquisition step S20. It is supposed to be. Specifically, in the inspection target acquisition step S201, the hardness of the heat-resistant member to be inspected is measured prior to the average particle size acquisition step S20, and the operating temperature of the heat-resistant member to be inspected is estimated from the measured hardness. I try to narrow down the places where extubation and replica collection are performed. That is, in another embodiment described below, the hardness and usage time of the heat-resistant member to be inspected are utilized by utilizing the fact that the hardness of the heat-resistant member to be inspected changes depending on the operating temperature and the operating time (aging time). The operating temperature is estimated from. Hereinafter, a detailed description will be given.

FIG. 11 is a flowchart showing a schematic procedure of an inspection method for heat-resistant members according to another embodiment.
The method for inspecting the heat-resistant member according to another embodiment includes a working temperature estimation step S1 based on hardness and a working temperature estimation step S3 based on precipitates. Here, the operating temperature estimation step S3 based on the precipitate includes a relationship acquisition step S10, an average particle size acquisition step S20, and an operating temperature parameter acquisition step S30 according to some of the above-described embodiments.
That is, in the method for inspecting a heat-resistant member according to another embodiment, as will be described in detail later, in step S2, based on the operating temperature of the heat-resistant member to be inspected estimated in the hardness-based operating temperature estimation step S1. It is determined whether or not the temperature load is high, and the operating temperature of the heat-resistant member to be inspected judged to have a high temperature load is estimated by the inspection method of the heat-resistant member according to some of the above-described embodiments. There is. For the heat-resistant member to be inspected, which is determined not to have a high temperature load in step S2, the operating temperature is not estimated by the heat-resistant member inspection method according to some of the above-described embodiments.

(Working temperature estimation step S1 based on hardness)
FIG. 12 is a flowchart showing the process in the operating temperature estimation step S1 based on the hardness. The working temperature estimation step S1 based on the hardness includes a correlation acquisition step S1010, a hardness measuring step S1020, and a working temperature estimation step S1030.

(Correlation acquisition step S1010)
FIG. 13 is a flowchart showing the processing in the correlation acquisition step S1010.
In the correlation acquisition step S1010, the correlation between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material is acquired by each of the steps S1101 to S1107 described below.

In the correlation acquisition step S1010, first, in the sample preparation step S1101, a sample for acquiring the correlation between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material is prepared. In the sample preparation step S1101, a plurality of samples having different heating temperatures and heating times are prepared.
For such a plurality of samples, for example, a plurality of untreated samples having the same composition or a similar composition as the heat-resistant member to be inspected are prepared, and these samples are heat-treated at different temperatures and different times (aging). It is obtained by performing treatment).

Next, in the sample hardness measurement step S1103, the hardness of a plurality of samples prepared in the sample preparation step S1101 is measured. For the hardness measurement, various measuring devices such as a Vickers hardness tester and an ultrasonic hardness tester can be used.

Next, in the master data acquisition step S1105, from the measurement results of the hardness of a plurality of samples measured in the sample hardness measurement step S1103, the hardness of the heat-resistant material, the operating temperature of the heat-resistant material (heating temperature), and the usage time of the heat-resistant material (heating time) , Prescription time) and get master data. FIG. 14 shows an example of the master data acquired in the master data acquisition step S1105. In the master data shown in FIG. 14, a graph in which the hardness of the heat-resistant material is on the vertical axis and the aging time is on the horizontal axis is shown for each heating temperature.

Next, in the master curve acquisition step S1107, the heat-resistant material extracted from the master data acquired in the master data acquisition step S1105 at the usage time of the heat-resistant member to be inspected, that is, for example, the operating time of the boiler 10 at the time of this periodic inspection. Obtain a master curve that shows the relationship between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material. FIG. 15 is a diagram showing an example of a master curve showing the relationship between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material, and FIG. 15 (a) shows the heat-resistant material extracted after a usage time of, for example, 10,000 hours. An example of a master curve showing the relationship between the hardness and the operating temperature of the heat-resistant material is shown. FIG. 15 (b) shows the relationship between the hardness of the heat-resistant material extracted at a usage time of 80,000 hours and the operating temperature of the heat-resistant material. This is an example of a master curve showing.

For example, when the operating time of the boiler 10 at the time of this periodic inspection is 10,000 hours, the hardness of the heat-resistant material and the heat-resistant material when the aging time is 10,000 hours are obtained from the master data shown in FIG. Read the operating temperature and. Then, for example, as shown in FIG. 15A, a master curve MA having the operating temperature on the horizontal axis and the hardness on the vertical axis is created.
Further, for example, when the operating time of the boiler 10 at the time of this periodic inspection is 80,000 hours, the hardness of the heat-resistant material when the aging time is 80,000 hours is determined from the master data shown in FIG. Read the operating temperature of the heat-resistant material. Then, for example, as shown in FIG. 15B, a master curve MB having the operating temperature on the horizontal axis and the hardness on the vertical axis is created.

As described above, in the correlation acquisition step S1010, the correlation between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material can be acquired from a plurality of samples having different heating temperatures and heating times.

Correlation The correlation between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material acquired in S1010 is to be inspected from the information (master data) about the hardness of the heat-resistant material, the operating temperature of the heat-resistant material, and the usage time of the heat-resistant material. It is the relationship (master curve) between the hardness of the heat-resistant material extracted by the usage time of the heat-resistant member and the operating temperature of the heat-resistant material.
As a result, the operating temperature of the heat-resistant member to be inspected can be immediately estimated from the hardness of the heat-resistant member to be inspected obtained by measurement and the above correlation.

(Hardness measurement step S1020)
FIG. 16 is a flowchart showing an example of a schematic procedure of the hardness measuring step S1020.
In the hardness measurement position determination step S1201, the hardness measurement position of the heat-resistant member to be inspected is determined. For example, if the heat-resistant member to be inspected is a steel pipe constituting the superheater 18 or the reheater 22 of the boiler 10, it is thermally depending on the period in which the superheater 18 or the reheater 22 is used and the operating conditions. A region where the load is estimated to be relatively large may be specified, and a plurality of points separated from the steel pipe in the region at predetermined intervals along the axial direction of the steel pipe may be determined as the hardness measurement positions. ..

Next, in the measurement step S1203, the hardness of the measurement position determined in the hardness measurement position determination step S1201 is measured. Various portable measuring devices such as an ultrasonic hardness tester can be used for measuring the hardness.

(Operating temperature estimation step S1030)
In the operating temperature estimation step S1030, the hardness of the heat-resistant member to be inspected obtained in the hardness measuring step S1020 is input to the correlation (master curve) between the hardness of the heat-resistant material acquired in the correlation acquisition step S1010 and the operating temperature of the heat-resistant material. By doing so, the operating temperature of the heat-resistant member to be inspected is estimated.

For example, when the operating time of the boiler 10 at the time of this periodic inspection is 10,000 hours and the hardness value at a certain measurement position is, for example, h1, the hardness value is as shown in FIG. 15 (a). It can be read from the master curve MA that the value of the operating temperature at which is h1 is T1.

Further, for example, when the operating time of the boiler 10 at the time of this periodic inspection is 80,000 hours and the hardness value at a certain measurement position is, for example, h2, the hardness is as shown in FIG. 15 (b). It can be read from the master curve MB that the value of the temperature at which the value of is h2 is T2 or T3.
In this case, there are two candidate values for the temperature at which the hardness value is h2. For example, the operating condition of the boiler 10 and the estimated value of the temperature at other nearby hardness measurement points are taken into consideration. Then, it may be determined which value is appropriate.
In this way, the operating temperature is estimated for all of the plurality of measurement positions of hardness.

After estimating the operating temperature from the hardness of the heat-resistant member to be inspected as described above, in step S2 of FIG. 11, it is determined whether or not the temperature load of the heat-resistant member to be inspected is high. Specifically, for example, it is based on the stress of the heat-resistant member to be inspected calculated from the steam pressure which is the operating condition of the boiler 10, the operating temperature estimated from the hardness of the heat-resistant member to be inspected, and the operating time of the boiler 10. Therefore, the remaining life of the heat-resistant member to be inspected is simply evaluated. If the remaining life of the heat-resistant member to be inspected simply evaluated is equal to or less than the threshold value, it is determined that the temperature load of the heat-resistant member to be inspected is high, and the remaining life of the heat-resistant member to be inspected simply evaluated is If it exceeds the threshold value, it is judged that the temperature load of the heat-resistant member to be inspected is not high.

Here, the above threshold value will be described. Let ta [time] be the period from the time of this periodic inspection to, for example, the next periodic inspection (next periodic inspection). If the remaining life of the heat-resistant member to be inspected, which was simply evaluated as described above, is less than the above ta [hours], if no measures such as repair are taken for the heat-resistant member to be inspected in this periodic inspection, The heat-resistant member to be inspected may creep rupture before the next periodic inspection.
However, even if the remaining life of the heat-resistant member to be inspected simply exceeds the above ta [time], considering the accuracy of the simple remaining life evaluation, the heat-resistant member to be inspected will be inspected next time. There is a risk of creep rupture at a point before this point.

Therefore, when the accuracy of the remaining life of the heat-resistant member to be inspected simply evaluated is, for example, twice the accuracy, the remaining life of the heat-resistant member to be inspected simply evaluated is the above ta [time]. If it exceeds twice the amount of the above with a certain margin, it can be determined that the heat-resistant member to be inspected does not creep rupture until the time of the next periodic inspection.
Therefore, the threshold value is, for example, a coefficient c (c) that is a value of 1 or more for giving a value (2.ta) twice the ta [time], which is the period until the next periodic inspection, to further have a margin. > 1) is multiplied by the value (2, c, ta).

That is, in step S2, it is determined whether or not the remaining life of the heat-resistant member to be inspected, which is simply evaluated, is equal to or less than the threshold value (2, c, ta) set as described above.
In step S2, when it is determined that the remaining life of the heat-resistant member to be inspected simply evaluated exceeds the threshold value (2, c, ta), the temperature load of the heat-resistant member to be inspected is not high and the said. It is determined that the heat-resistant member to be inspected will not creep rupture until at least the next periodic inspection, and each treatment in the operating temperature estimation step S3 based on the deposit is not performed on the heat-resistant member to be inspected.
However, in step S2, when it is determined that the remaining life of the heat-resistant member to be inspected, which is simply evaluated, is equal to or less than the threshold value (2, c, ta), the temperature load of the heat-resistant member to be inspected is high. It is determined that the heat-resistant member to be inspected may creep rupture by the next periodic inspection, and each treatment in the operating temperature estimation step S3 based on the precipitate is carried out.

As described above, the operating temperature estimation step S3 based on the precipitate includes the relationship acquisition step S10, the average particle size acquisition step S20, and the operating temperature parameter acquisition step S30 according to some of the above-described embodiments. It is a process. Therefore, a detailed description of the operating temperature estimation step S3 based on the precipitate will be omitted.

As described above, in the method for inspecting the heat-resistant member according to the other embodiment, prior to the average particle size acquisition step S20, the hardness measuring step S1020 for measuring the hardness of the heat-resistant member to be inspected, and the hardness of the heat-resistant material and the heat-resistant material It is provided with an operating temperature estimation step S1030 that estimates the operating temperature of the heat-resistant member to be inspected by inputting the hardness of the heat-resistant member to be inspected obtained in the hardness measuring step S1020 into the correlation with the operating temperature of the above. Then, the necessity of carrying out the average particle size acquisition step S20 is determined based on the working temperature of the heat-resistant member to be inspected estimated in the working temperature estimation step S1030.

As a result, the operating temperature of the heat-resistant member to be inspected is estimated by a simple method of measuring the hardness of the heat-resistant member to be inspected, and it is determined that more detailed estimation of the operating temperature is necessary based on the estimated operating temperature. In this case, the average particle size acquisition step S20 can be carried out. As a result, it is possible to shorten the time for estimating the operating temperature of the heat-resistant member to be inspected and improve the accuracy of estimating the operating temperature of the heat-resistant member to be inspected.
Further, in the method for inspecting heat-resistant members according to another embodiment, the operating time of the boiler 10 is extracted from the master data which is information on the hardness, heating temperature, and aging time of a plurality of samples prepared in the sample preparation step S1101. Since the master curve is acquired, it is not necessary to verify the validity of temperature acceleration when acquiring the master curve.

(About other embodiments relating to the master curve)
Hereinafter, other embodiments relating to the master curve will be described. In the other embodiment described above, the master curve acquired in the master curve acquisition step S1107 of the correlation acquisition step S1010 shown in FIG. 13 provides information on the hardness of the heat-resistant material, the operating temperature of the heat-resistant material, and the operating time of the heat-resistant material. It was the relationship (master curve) between the hardness of the heat-resistant material extracted from (master data) by the usage time of the heat-resistant member to be inspected and the operating temperature of the heat-resistant material. On the other hand, in another embodiment relating to the master curve described below, the heat-resistant material is obtained from information (master data) about the hardness of the heat-resistant material, the operating temperature of the heat-resistant material, and the usage time of the heat-resistant material as the master curve. Obtain the relationship between the hardness of the heat-resistant material and the parameters related to the operating temperature and operating time of the heat-resistant material.

In another embodiment relating to the master curve, in the master curve acquisition step S1107 of the correlation acquisition step S1010 shown in FIG. 13, the hardness of the heat-resistant material, the operating temperature of the heat-resistant material, and the use of the heat-resistant material are obtained from the master data acquired in the master data acquisition step S1105. Get a master curve that shows the relationship with parameters related to time.
FIG. 17 is a diagram showing an example of a master curve showing the relationship between the hardness of the heat-resistant material and the parameters related to the operating temperature and the operating time of the heat-resistant material. The vertical axis is the hardness of the heat-resistant material, and the operating temperature and use of the heat-resistant material are shown. It is a graph of the master curve MC with the temperature / time parameter λa which is a parameter related to time taken on the horizontal axis. Here, the temperature / time parameter λa is, for example, a Larson mirror parameter represented by the above-mentioned equation (1).
That is, the correlation between the hardness of the heat-resistant material acquired in the correlation acquisition step S1010 and the operating temperature of the heat-resistant material is a correlation for obtaining the temperature / time parameter λa from the hardness of the heat-resistant material. Then, the operating temperature can be obtained from the above-mentioned equation (1) based on the obtained value of the temperature / time parameter λa and the operating time.

For example, when the hardness value at a certain measurement position is, for example, h4, as shown in FIG. 17, it is read from the master curve MC that the value of the temperature / time parameter λa at which the hardness value is h4 is λ4. Can be done. Then, the operating temperature at a certain measurement position can be obtained from the value (λ4) of the temperature / time parameter λa thus obtained and, for example, the operating time of the boiler 10 at the time of this periodic inspection.

As described above, in another embodiment relating to the master curve, the correlation between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material acquired in the correlation acquisition step S1010 is the hardness of the heat-resistant material, the operating temperature of the heat-resistant material, and the use of the heat-resistant material. It is the relationship between the hardness of the heat-resistant material obtained from the information about time (master data), the operating temperature of the heat-resistant material, and the temperature / time parameter λa related to the operating time.
Since the temperature / time parameter λa related to the operating temperature and operating time of the heat-resistant material is used, the operating time of the heat-resistant member to be inspected is longer than the longest heating time in the sample prepared to obtain the above correlation. However, the operating temperature of the heat-resistant member to be inspected can be estimated.

The present invention is not limited to the above-described embodiment, and includes a modified form of the above-described embodiment and a combination of these embodiments as appropriate.
For example, in some of the above-described embodiments, a sample for observing the tissue is obtained by excising a part of the device in which the heat-resistant member to be inspected is used. However, for example, as described above, a replica of the surface of the heat-resistant member to be inspected may be obtained by the replica method. In this case, since the shape of the precipitate on the surface of the heat-resistant member to be inspected is transferred to the acquired replica, the shape can be observed. Further, depending on the replica acquisition method, the precipitate may fall off from the tissue and adhere to the acquired replica. In this case, for example, by using a scanning electron microscope, the precipitate adhered to the replica may be attached. Can be identified directly.
However, if the precipitate itself is not attached to the acquired replica, it may not be possible to identify the precipitate from the acquired replica. That is, depending on the type of precipitate, the precipitate may not be identified only by the shape of the precipitate transferred to the acquired replica.

Even in such a case, if it can be determined from the appearance characteristics such as the shape and particle size of the precipitate that it is at least one of the above-mentioned first-class precipitates and second-class precipitates. For example, by using the above-mentioned third master curve, the operating temperature of the heat-resistant member can be estimated.

Further, in some of the above-described embodiments, the case where two types of precipitates of the first kind and the second kind of precipitates can exist as the precipitates related to the estimation of the operating temperature has been described as an example, but the use has been described. At least one type of precipitate related to temperature estimation may be present, and three or more types may be present.

Further, for example, the heat-resistant member to be inspected may be a part other than the superheater 18 and the reheater 22 of the boiler 10. Further, the heat-resistant member to be inspected may be one used in high-temperature equipment other than the boiler 10. Furthermore, the steel type of the heat-resistant member to be inspected is not limited to high-strength austenitic steel.

In some of the above-described embodiments, in the relationship acquisition step S10 shown in FIG. 3, the average particle size of the precipitates having the first particle size or more among the precipitates in the structure of the heat-resistant material, the operating temperature of the heat-resistant material, and the operating temperature of the heat-resistant material If the relationship with the parameters related to the usage time has already been obtained, it is not necessary to carry out again when estimating the usage temperature of the heat-resistant member to be inspected thereafter.
Similarly, in some of the above-described embodiments, in the correlation acquisition step S1010 shown in FIG. 13, if the master curve shown in FIGS. 15 and 17 has already been acquired, the heat-resistant member to be inspected thereafter is used. There is no need to re-execute when estimating the temperature.

10 Boiler 18 Superheater 22 Reheater

Claims (14)

A relationship acquisition step for acquiring the relationship between the average particle size of the precipitate having the first particle size or more in the structure of the heat-resistant material and the parameters related to the operating temperature and the operating time of the heat-resistant material.
Among the precipitates in the structure of the heat-resistant member to be inspected, the average particle size acquisition step of obtaining the average particle size of the precipitates having the second particle size or more, which is the particle size corresponding to the first particle size, by measurement.
An operating temperature parameter acquisition step of obtaining a parameter relating to the operating temperature of the heat-resistant member to be inspected based on the relationship acquired in the relationship acquisition step and the average particle size obtained in the average particle size acquisition step.
A method for inspecting heat-resistant members. The first particle size is n micrometers.
The method for inspecting a heat-resistant member according to claim 1, wherein the second particle size is n micrometers. The first particle size is the particle size of the nth precipitate in order from the deposit having the largest diameter among the precipitates in the structure of the heat-resistant material.
The inspection of the heat-resistant member according to claim 1, wherein the second particle size is the particle size of the nth precipitate in order from the precipitate having the largest diameter among the precipitates in the structure of the heat-resistant member to be inspected. Method. The first particle size is the particle size of the smallest precipitate in the precipitates contained in the number of the upper n% having a large particle size among the precipitates in the structure of the heat-resistant material.
The second particle size is the particle size of the smallest precipitate among the precipitates in the structure of the heat-resistant member to be inspected, which is included in the number of the upper n% having a large particle size. The method for inspecting the heat-resistant member described. The precipitate in the structure of the heat-resistant material contains at least a first-class precipitate and a second-class precipitate of different types.
In the relationship acquisition step, the first relationship between the average particle size of the precipitate having the first particle size or more among the first-class precipitates and the parameters related to the operating temperature and the operating time of the heat-resistant material, and the second type. According to any one of claims 1 to 4, the second relationship between the average particle size of the precipitate having the first particle size or more and the parameters relating to the operating temperature and the operating time of the heat-resistant material is obtained. The method for inspecting the heat-resistant member described. The precipitate in the structure of the heat-resistant material contains at least a first-class precipitate and a second-class precipitate of different types.
The relationship acquisition step is a third of the average particle size of the first-class precipitate and the second-class precipitate having a particle size of the first particle size or higher and parameters relating to the operating temperature and the operating time of the heat-resistant material. The method for inspecting a heat-resistant member according to any one of claims 1 to 4, wherein a relationship is obtained. In the relationship acquisition step, when the standard error between the average particle size and the parameter used for acquiring the relationship and the acquired relationship is out of the permissible range, the first particle size is changed. The method for inspecting a heat-resistant member according to any one of claims 1 to 6, wherein the relationship is reacquired. The method for inspecting a heat-resistant member according to any one of claims 1 to 7, wherein the heat-resistant material and the heat-resistant member to be inspected are made of high-strength austenitic steel. Among the precipitates in the structure of the heat-resistant member to be inspected, the average grain size of the precipitate having a second particle size or more, which is the particle size corresponding to the first particle size of the precipitate in the structure of the heat-resistant material, is determined by measurement. Diameter acquisition process and
Among the precipitates in the structure of the heat-resistant material, the relationship between the average particle size of the precipitate having the first particle size or more and the parameters related to the operating temperature and the operating time of the heat-resistant material, and the average particle size acquisition step are obtained. An operating temperature parameter acquisition step of obtaining a parameter related to the operating temperature of the heat-resistant member to be inspected based on the average particle size
A method for inspecting heat-resistant members. From a plurality of standard samples having different heating temperatures and heating times, the average particle size of the precipitates having the first particle size or more among the precipitates in the structure of the heat-resistant material and the parameters relating to the operating temperature and the operating time of the heat-resistant material. The method for inspecting a heat-resistant member according to claim 9, further comprising a relationship acquisition step for acquiring a relationship. Prior to the average particle size acquisition step, a hardness measuring step of measuring the hardness of the heat-resistant member to be inspected, and a hardness measuring step.
The operating temperature of the heat-resistant member to be inspected is estimated by inputting the hardness of the heat-resistant member to be inspected obtained in the hardness measuring step into the correlation between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material. Further equipped with an operating temperature estimation process,
The step according to any one of claims 1 to 10, wherein the necessity of carrying out the average particle size acquisition step is determined based on the working temperature of the heat-resistant member to be inspected estimated in the working temperature estimation step. How to inspect heat-resistant materials. The method for inspecting a heat-resistant member according to claim 11, further comprising a step of obtaining a correlation between the hardness of the heat-resistant material and the operating temperature of the heat-resistant material from a plurality of samples having different heating temperatures and heating times. The correlation is the hardness of the heat-resistant material and the hardness of the heat-resistant material extracted from the information about the hardness of the heat-resistant material, the operating temperature of the heat-resistant material, and the usage time of the heat-resistant material by the usage time of the heat-resistant member to be inspected. The method for inspecting a heat-resistant member according to claim 11 or 12, which is related to the operating temperature. The correlation is the hardness of the heat-resistant material and the parameters related to the temperature and time of use of the heat-resistant material obtained from the information about the hardness of the heat-resistant material, the operating temperature of the heat-resistant material, and the usage time of the heat-resistant material. The method for inspecting a heat-resistant member according to claim 11 or 12, which is related to the method.

Images