JP2003270220A - Method for estimating service lifetime of high temperature member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To nondestructively estimate a residual service lifetime of a high temperature member. <P>SOLUTION: A sound velocity value of a turbine rotor is measured by irradiating ultraviolet rays to an actual machine steam turbine rotor. A ratio of the sound velocity value of the turbine rotor and the sound velocity value of an unused material and the ratio of the sound velocity value of a no-load heating material and the sound velocity value of the unused material are respectively calculated together with each measuring time. An increase amount of a sound velocity ratio is obtained from the difference of each calculated value in the same measuring time. A creep damage rate ϕc is obtained by applying the increase amount Va of the sound velocity ratio to a diagram which shows the relation of the increase amount of the sound velocity ratio and the creep damage rate and the remaining service lifetime of the turbine rotor is calculated from the creep damage rate ϕc. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for predicting the life of high temperature members, and in particular, nondestructively detecting the deterioration state of a material used in a steam turbine or the like, which is caused by long-term operation in a high temperature atmosphere. The present invention relates to a high temperature member life prediction method suitable for predicting the life of a high temperature member from the detected deterioration state.

[0002]

2. Description of the Related Art Rotor shafts, casings, etc., which constitute a steam turbine, are made of, for example, CrM.
It is manufactured from oV low alloy steel and 12Cr ferritic stainless steel. Generally, when a high temperature member of this type is exposed to an atmosphere of 300 to 600 ° C. for a long time, a brittleness phenomenon occurs in which toughness and ductility are reduced. That is, the high-temperature member, when exposed to the embrittlement temperature region for a long time, metallurgically precipitates carbides in the crystal grain boundaries and grains, or wants to generate voids in the grain boundaries, or the amount of impurity elements is It is known that the number of grains increases and the grain boundaries and the grain boundaries become brittle and embrittle.

For this reason, when a rotor shaft for a steam turbine or a casing is used in an embrittlement temperature range, it operates for a long time in a high-temperature atmosphere, so that embrittlement is accumulated and further due to action stress. Cracks can occur and can even lead to destruction accidents.

Therefore, as a method for investigating the embrittlement state of a device exposed to a high temperature atmosphere for a long time, conventionally, a test piece is directly cut out from a high temperature member which is actually used, and the cut out test piece is used. A destructive test was being conducted.

[0005]

In the prior art, when investigating the embrittlement state of equipment exposed to high temperatures, a part of it must be cut out from the high temperature member that is actually used, and a destructive test must be performed. It takes time and effort to cut out the test piece or repair the cut-out portion of the test piece. Therefore, it is required to nondestructively detect the embrittlement status of high temperature members such as rotors and casings that are actually used, which is extremely important from the viewpoint of preventing destruction accidents of actual machines. is there.

[0006] In particular, there are 10 thermal power plants in Japan.
More than half of the equipment has been in operation for more than a year and may reach the end of its life depending on the equipment in the plant. It is necessary to replace the equipment or construct a new plant when the life of various equipment of the plant reaches the end of life, but enormous cost is required to construct a new plant. Therefore, it is extremely important to be able to measure the remaining life (remaining life) of the equipment that is approaching the life with high accuracy, and if the remaining life of the equipment is known, it is possible to accurately know when to replace the equipment. , The equipment can be used effectively until the replacement time, and the merit is very large.

An object of the present invention is to provide a method for predicting the service life of a high temperature member that can predict the remaining service life of the high temperature member nondestructively.

[0008]

In order to achieve the above object, the present invention provides a method of irradiating a high temperature member containing metal in a high temperature atmosphere with ultrasonic waves and propagating the ultrasonic wave at a velocity of the ultrasonic wave. A sound velocity value measuring step of measuring as a sound velocity value of the high temperature member, a sound velocity value of the unused material and a sound velocity value of the high temperature member measured as a velocity of ultrasonic waves propagating an unused material of the same material as the high temperature member Of the sound velocity value of the unloaded heating material and the sound velocity value of the unused material measured as the velocity of the ultrasonic wave propagating in the unloaded heating material that was in the high temperature atmosphere in the same material as the high temperature member and the ratio A sound velocity ratio increase amount calculating step of calculating the ratio and calculating the sound velocity ratio increase amount from the difference between the calculated values of the high temperature member and the no-load heating member in the same heating time, and the relationship between the sound velocity ratio increase amount and the creep damage rate. The sound velocity ratio increase amount is calculated in the diagram Is obtained by employing the life prediction method for a high temperature member comprising a residual lifetime calculating step of calculating a by fitting the calculated sound velocity ratio increase residual life of the high temperature member with extent.

According to the above-mentioned means, for a high temperature member which is actually used in a high temperature atmosphere, for example, an atmosphere of 300 to 600 ° C., for example, an ultrasonic probe of an ultrasonic flaw detector is used. The ultrasonic velocity is applied to the high temperature member to obtain the sound velocity value of the high temperature member, and the ratio of the sound velocity value of the high temperature member to the sound velocity value of the unused material and the sound velocity value of the unloaded heating material and the sound velocity value of the unused material are calculated. The ratio is calculated, and the sound velocity ratio increase amount (sound velocity ratio increase amount = (sound velocity value of high temperature member) / (sound velocity value of unused material) − (sound velocity of unloaded heating material is calculated from the difference between the calculated values at the same measurement time). (Value) / (sound velocity value of unused material)), and a diagram showing the relationship between the sound velocity ratio increase amount and the creep damage ratio, for example, a line in which the sound velocity ratio increase amount and the creep damage ratio are in a proportional relationship with each other. Apply the calculated sound velocity ratio increase amount to the figure to determine the remaining life of the high temperature member. Because you have to exit, it is possible to predict the remaining life of the high temperature member without destroying the high temperature member. Then, by replacing the device constituting the high-temperature member from the remaining life, it is possible to prevent the accidental destruction of the device constituted by the high-temperature member.

Here, when calculating the remaining life of the high temperature member, the calculated sound velocity ratio increase amount is applied to a diagram showing the relationship between the sound velocity ratio increase amount and the creep damage rate as shown in FIG. This is possible.

For example, when the sonic ratio increase of the high temperature member used for the rotor shaft or casing of the steam turbine is Va, the creep damage ratio φc =
0.25 is required. The remaining life t2 in this case is obtained from the following equation (1).

[0012]

## EQU00001 ## t2 = t1 (1 / .phi.c-1) (1) where, t1; usage time of high temperature member (h) .phi.c; creep damage rate For example, t1 = 3000h, creep damage rate .phi.c = 0 ．
In the case of 25, the remaining life t2 = 90000h.
That is, it can be estimated that there is a residual life of 90000 hours before the high temperature member is destroyed.

In predicting the life of the high temperature member, it is possible to employ a method of measuring the sound velocity values of the high temperature member, the no-load heating material and the unused material, respectively, as shown below.

A first sound velocity value measuring step of irradiating a high temperature member containing metal in a high temperature atmosphere with ultrasonic waves and measuring a velocity of the ultrasonic wave propagating through the high temperature member as a sound velocity value of the high temperature member; The speed of ultrasonic waves propagating in the no-load heating material by irradiating the no-load heating material with ultrasonic waves in a high-temperature atmosphere of the same material as the high-temperature member in an unloaded state A second sound velocity value measuring step of measuring as a sound velocity value, and irradiating an ultrasonic wave to an unused material of the same material as the high temperature member and propagating the unused material with an ultrasonic wave velocity of the unused material. And a ratio of the sound velocity value of the high temperature member to the sound velocity value of the unused material and the ratio of the sound velocity value of the unloaded heating material to the sound velocity value of the unused material. Calculate and calculate the same heating time for the high temperature member and the no-load heating member. The sound velocity ratio increase amount calculation step of calculating the sound velocity ratio increase amount from the difference between the calculated values, and the sound velocity calculated in the sound velocity ratio increase amount calculation step in the diagram showing the relationship between the sound velocity ratio increase amount and the creep damage ratio. And a residual life calculation step of calculating a residual life of the high temperature member by applying a specific increase amount.

The following method can be used to generate a diagram showing the relationship between the creep damage rate and the sound velocity ratio increase amount.

With respect to a plurality of test bodies containing the same metal as the high temperature member, one test body is subjected to a no-load heating test in a high temperature atmosphere, and the other test body is subjected to a creep test in a high temperature atmosphere. A test step of performing a creep damage rate calculation step of calculating a creep damage rate from the ratio of the test time required for the creep test of the other test body and the creep rupture time indicating the time until the other test body breaks. And measuring the speed of ultrasonic waves propagating through the unloaded test body by irradiating the unloaded test body with ultrasonic waves as one of the unloaded test bodies as the sound velocity value of the unloaded test body. 4 of the sound velocity value measuring step, and using the other test body as a creep damage test body, the creep damage test body is irradiated with ultrasonic waves and the speed of ultrasonic waves propagating through the creep damage test body is changed to the creep damage test body. A fifth sound velocity value measuring step of measuring as a sound velocity value, a ratio of the sound velocity value of the creep damage test body to the sound velocity value of the unused material, and the sound velocity value of the unloaded test body and the sound velocity value of the unused material. And the heating test time of the creep damage test and the unloaded test body are calculated respectively, and the sound speed ratio increase amount is calculated for the test body by calculating the sound speed ratio increase amount from the difference between the calculated values at the same heating test time. Process,
A method of predicting the life of a high temperature member, comprising: a diagram generating step of generating a diagram showing a relationship between the creep damage ratio and the sonic ratio increase amount from the creep damage ratio and the sonic ratio increase amount.

The following members can be used as the high temperature member.

(1) The high temperature member is formed as a rotor or a casing of a steam turbine, the high temperature member forming the rotor is CrMoV forged steel, and the high temperature member forming the casing is CrMoV forged steel or cast steel. .

(2) The high temperature member has a C: 0.01-
0.4%, Ni: 3% or more, Cr: 8 to 13% or less,
V: 1% or less, Nb: 0.5% or less, N: 0.1% or less, and at least one of Mo: 3% or less and W: 1% or less. Or, Ni: 3% or less, Cr: 8 to 13% or less,
V: 1% or less, Nb: 0.5% or less, N: 0.1% or less, Mo: 3% or less, W: 10%
At least one of the following is included.

The diagram in FIG. 1 shows that the increase in the sound velocity ratio increases linearly with the increase in the creep damage rate. This is because the material of the high temperature member applied in the present invention hardly causes creep voids. On the other hand, when a low alloy steel is used, creep voids occur after 1/2 of the fracture life (creep damage rate = 0.5), and increase as the time becomes longer. On the other hand, the speed of sound decreases with the occurrence of creep voids.
Therefore, when the sound velocity value is applied to FIG. 1 by applying the material in which the creep voids are generated, the increasing rate of the sound velocity ratio is less likely to increase from the time when the creep voids are generated. That is, since the tendency of occurrence of creep voids differs depending on the material, it is necessary to previously acquire, as reference data, a diagram showing the relationship between the creep damage rate and the amount of increase in sound velocity ratio for each material.

The sound velocity value of the high temperature member may vary depending on the heating temperature even if the holding time is the same. In particular,
In the case of a large heating member such as the rotor shaft or casing of a steam turbine, there are places where the temperature distribution is different. Therefore, it is desirable to create data indicating the relationship between the actual sound velocity value measurement position and the same heating temperature as a master curve and use this master curve.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

In this embodiment, prior to predicting the life of a high temperature member such as a rotor (rotor shaft) of a steam turbine or a casing, a diagram showing the relationship between the creep damage rate and the sonic ratio increase amount (master). A process until a curve is generated will be described.

First, a creep test piece (creep test piece) and a no-load heating test piece (no-load heating test piece) were sampled from a rotor of a steam turbine as a plurality of test pieces, and the creep test piece had a high temperature atmosphere, For example, 600 ℃
No-load heating test is performed in the atmosphere of 600 ° C for the no-load heating test piece in the same atmosphere as the creep test (a test that only heats without applying a load)
I went. Both test pieces were sampled in the rotor radial direction and the axial direction.

Table 1 below shows the main chemical composition (% by weight) of the steam turbine rotor 12Cr steel virgin material applied as the test base material.

[0026]

[Table 1] The sampling position of the test piece for measuring the sound velocity value from the creep test piece is the parallel part of the test piece, and the shape of the creep test piece is 10 mm in the diameter of the parallel part and 50 mm in the length of the parallel part. The shape of the no-load heating test piece is 10 mm square and 75 m long.
m. Then, in the creep test, in order to obtain test pieces having different creep damage rates, the creep test was interrupted to prepare test pieces. The heating time of the no-load heating test piece was the same as the interruption test time of the creep test. In the process of performing the creep test for the creep test piece and the no-load heating test for the no-load heating test piece, the sound velocity value of the creep test piece (creep damage test piece) and the no-load heating test piece (no-load test piece) Was sequentially measured. The shape of the test piece for measuring the sound velocity value is 10 mm in diameter for the creep damage material (creep damage test body).
The length is 10 mm, and the unloaded heating material is 10 mm square × 10 mm long. When the creep damage material ruptures in the creep test, the creep rupture time (creep damage ratio φ
The creep damage rate φc was calculated from the ratio of c = 1) to the test time required for the creep test, and the sound velocity values of the creep damaged material and the no-load heating material were measured at an arbitrary time from the start of the test.

When measuring the sound velocity value, the container is filled with water, and the creep damage material and the no-load heating material as each test piece are submerged and the ultrasonic probe of the ultrasonic flaw detector is submerged. Was applied. Further, in the present embodiment, each test piece and the ultrasonic probe were not brought into direct contact with each other, and water was used as a contact medium to maintain a constant interval between each test piece and the ultrasonic probe. The distance between the two was adjusted so that the transmission focal point of the ultrasonic probe was at the center of the wall pressure of each test piece. The characteristics of the ultrasonic probe are 7MHz in the low frequency narrow band.
Is. After adjusting the position, irradiate ultrasonic waves from the ultrasonic probe to each test piece, find the time from when the ultrasonic wave is irradiated until the reflected wave is incident, and the sound wave that propagates through each test piece The sound velocity value of each test piece is measured as the sound velocity of.

Further, in the present embodiment, in order to make the sound velocity value of each test piece dimensionless by the sound velocity value of an unused material, the test piece is made of the same material (having the same chemical composition and structure). The sound velocity value of the unused material is also measured. After that, the ratio of the sound velocity value of the creep-damaged material and the sound velocity value of the unused material and the ratio of the sound velocity value of the unloaded heating material and the sound velocity value of the unused material were calculated by combining the measurement times. The measurement results at this time are shown in FIGS. 2 and 3.

FIG. 2 shows the ratio of the sound velocity value of the creep damage test piece taken from the radial direction of the rotor in the stress direction to the sound velocity value of the unused material, and the sound velocity value of the unloaded heating material and the sound velocity of the unused material. The relationship between the ratio and the creep damage rate is shown.

From FIG. 2, the sonic velocity ratio of the no-load heating material tends to increase once at the creep damage rate φc = 0.2 and decrease at the creep damage rate φc = 0.2 or more. On the other hand, in the case of the creep damage material, contrary to the former case, the creep damage rate φc = 0.2 is once reduced, and it is gradually increased above that.

FIG. 3 shows the ratio of the sound velocity value in the direction in which the measurement direction of the creep damage test piece taken from the rotor axial direction is orthogonal to the stress direction (stress right angle direction) to the sound velocity value of the unused material, and no load heating. The relationship between the ratio of the sound velocity value of the material and the sound velocity value of the unused material and the creep damage rate is shown.

From FIG. 3, it can be seen that both the sound velocity ratio of the unloaded heating material and the sound velocity ratio of the creep damaged material tend to increase little by little as the creep damage ratio increases.

As can be seen from the measurement results of FIGS. 2 and 3, even if the sound velocity ratio, which is the ratio between the sound velocity value of each test piece and the sound velocity value of the unused material, is obtained, each line diagram shows a substantially flat characteristic. Therefore, it is difficult to uniquely obtain a single creep damage rate from a certain sound velocity ratio.

Therefore, in the present embodiment, the sound velocity ratio, which is the ratio between the sound velocity value of the creep damage test piece and the sound velocity value of the unused material, and the ratio of the sound velocity value of the unloaded heating material and the sound velocity value of the unused material. After calculating the sound velocity ratio for each measurement time, calculate the sound velocity ratio increase amount from the difference between each calculated value (sound velocity ratio) at the same measurement time, and obtain the relationship between this calculation result and the creep damage rate. And FIG. 4 shows the relationship between the increase in sound velocity ratio and the creep damage rate at this time.

From FIG. 4, there is a proportional relationship in which the sonic ratio increase amount and the creep damage ratio increase linearly with each other in both the stress direction and the orthogonal direction (stress right angle direction) in which the creep damage test piece is orthogonal to the stress. I know there is. Therefore, it is possible to uniquely obtain a single creep damage rate by obtaining the sound velocity ratio increase amount.

Therefore, in the present embodiment, a diagram showing the relationship between the creep damage rate and the sound velocity ratio increase amount is generated as a master curve based on the measurement results shown in FIG. Figure 5
Shows the characteristics of the master curve obtained from FIG.

After the master curve is generated, the remaining life of the actual turbine rotor is estimated. In this case, ultrasonic waves are emitted toward the actual turbine rotor (rotor shaft),
The velocity of the ultrasonic wave propagating through the turbine rotor is measured as the sound velocity value of the turbine rotor.

After that, based on the sound velocity values (the sound velocity value of the unused material and the sound velocity value of the unloaded heating material) measured in the process of generating the master curve, the sound velocity value of the turbine rotor and the previously obtained unused sound velocity value. The ratio between the sound velocity value of the material (sound velocity ratio) and the ratio of the sound velocity value of the no-load heating material and the sound velocity value of the unused material (sound velocity ratio) obtained in advance are calculated by combining the measurement times, and the same measurement time is calculated. The sound speed ratio increase amount is calculated from the difference between the respective calculated values (sound speed ratio).

Here, for example, in an atmosphere of 600 ° C., 5
When the sound speed ratio increase amount of the actual turbine rotor that has been operating for 0000 hours is Va, the sound damage ratio increase amount Va is applied to the master curve of FIG. 5 to obtain a creep damage rate of φc = 0.5. can get. When this result is applied to the above-mentioned formula (1) to calculate, a residual life of 50,000 hours can be obtained. That is, it can be estimated that the estimated remaining life of the turbine rotor used in this embodiment is 50,000 hours.

The test material applied in the above embodiment is
It is a material with very little generation of creep voids. Therefore, it can be said that the results of FIGS. 4 and 5 are results of the material that does not include the influence of creep voids. Therefore, as described above, when a material in which creep voids are generated is applied, a diagram (master curve) having a tendency different from those in FIGS. 4 and 5 is obtained.

However, even if creep voids are generated in the test body, the relationship between the sonic ratio increase of the same material and the creep damage rate is acquired in advance as basic data, and a master curve is formed according to this basic data. The residual life can be easily estimated even when other materials are used by applying the increase amount of the sound velocity ratio of the actual machine to this master curve.

As described above, according to this embodiment, it is possible to easily estimate the remaining life of the high temperature member such as the actual steam turbine rotor and the casing. Therefore, the equipment (the actual machine) should be replaced based on the estimation result. Therefore, it becomes possible to prevent the accident of destruction of the actual machine.

When obtaining the sound velocity ratio increase amount,
When determining the sound velocity value of a high-temperature member, the ultrasonic velocity of the ultrasonic wave that propagates through the unloaded heating material is irradiated by applying ultrasonic waves to the unloaded heating material that was in the high temperature atmosphere of the same material as the high temperature member in the unloaded state. In addition to measuring the sound velocity value of the unloaded heating material, it is also possible to irradiate the unused material of the same material as the high temperature member with ultrasonic waves and measure the speed of the ultrasonic wave propagating through the unused material as the sound velocity value of the unused material. it can.

[0044]

As described above, according to the present invention,
The remaining life of the high temperature member can be predicted without destroying the high temperature member. Therefore, by exchanging the equipment that constitutes the high temperature member from the remaining life, it is possible to prevent damage accidents of the equipment configured by the high temperature member. It will be possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a sound speed ratio increase amount and a creep damage rate according to the present invention.

FIG. 2 is a diagram showing a relationship between a creep damage rate and a sound velocity ratio of a creep damage material and an unloaded heating material in a rotor radial direction.

FIG. 3 is a diagram showing the relationship between the creep damage rate and the sound velocity ratio of the creep damage material and the no-load heating material in the rotor axial direction.

FIG. 4 is a graph showing the relationship between the sound velocity ratio increase amount and the creep damage rate according to the present invention.

FIG. 5 is a diagram for explaining a method of estimating the remaining life of an actual machine from a master curve.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyuki Doi             7-1-1, Omika-cho, Hitachi-shi, Ibaraki Prefecture             Inside the Hitachi Research Laboratory, Hitachi Ltd. (72) Inventor Shigeyoshi Nakamura             7-1-1, Omika-cho, Hitachi-shi, Ibaraki Prefecture             Inside the Hitachi Research Laboratory, Hitachi Ltd. (72) Inventor Masahiko Arai             7-1-1, Omika-cho, Hitachi-shi, Ibaraki Prefecture             Inside the Hitachi Research Laboratory, Hitachi Ltd. (72) Inventor Kojiro Higuchi             3-7-1, Ichibancho, Aoba-ku, Sendai City, Miyagi Prefecture               Tohoku Electric Power Co., Inc. (72) Inventor Yasuhiro Suzuki             3-7-1, Ichibancho, Aoba-ku, Sendai City, Miyagi Prefecture               Tohoku Electric Power Co., Inc. (72) Inventor Masahide Maruyama             3-7-1, Ichibancho, Aoba-ku, Sendai City, Miyagi Prefecture               Tohoku Electric Power Co., Inc. (72) Inventor Masahiro Endo             3-7-1, Ichibancho, Aoba-ku, Sendai City, Miyagi Prefecture               Tohoku Electric Power Co., Inc. F term (reference) 2G047 AA07 AC06 BC02 BC11 CA01                       EA10 EA19 GG27 GG33

Claims (5)

[Claims] 1. A sonic velocity value measuring step of irradiating a high temperature member containing metal in a high temperature atmosphere with ultrasonic waves to measure a velocity of an ultrasonic wave propagating through the high temperature member as a sonic velocity value of the high temperature member. The ratio of the sound velocity value of the unused material and the sound velocity value of the high temperature member measured as the velocity of the ultrasonic wave propagating through the unused material of the same material as the high temperature member and the same material as the high temperature member in a high temperature atmosphere The ratio of the sound velocity value of the unloaded heating material measured as the velocity of the ultrasonic wave propagating through the unloaded heating material that was present and the sound velocity value of the unused material was calculated, and the high temperature member and the unloaded heating member were heated to the same temperature. The sound speed ratio increase amount calculation step of calculating the sound speed ratio increase amount from the difference between the calculated values in time, and the sound speed ratio increase amount calculation step in the diagram showing the relationship between the sound speed ratio increase amount and the creep damage ratio Applying the sound velocity ratio increase amount to the high temperature member And a remaining life calculation step of calculating the remaining life of the high temperature member. 2. A first sound velocity value measurement for irradiating a high temperature member containing metal in a high temperature atmosphere with ultrasonic waves and measuring a velocity of the ultrasonic wave propagating through the high temperature member as a sound velocity value of the high temperature member. The process and the speed of ultrasonic waves propagating through the unloaded heating material by irradiating ultrasonic waves to the unloaded heating material that was in the high temperature atmosphere of the same material as the high temperature member in the unloaded state A second sound velocity value measuring step of measuring the sound velocity value of the material, and irradiating an ultrasonic wave to an unused material of the same material as the high temperature member, and changing the speed of the ultrasonic wave propagating through the unused material to that of the unused material. A third sound velocity value measuring step of measuring as a sound velocity value, a ratio of the sound velocity value of the high temperature member and the sound velocity value of the unused material, and the sound velocity value of the unloaded heating material and the sound velocity value of the unused material. The ratio is calculated and the high temperature member and the no-load heating member are heated at the same heating time. In the sound velocity ratio increase amount calculation step of calculating the sound velocity ratio increase amount from the difference between the calculated values, the sound velocity calculated in the sound velocity ratio increase amount calculation step in the diagram showing the relationship between the sound velocity ratio increase amount and the creep damage rate. And a residual life calculation step of calculating a residual life of the high temperature member by applying a specific increase amount. 3. The method of predicting the life of a high temperature member according to claim 1, wherein a plurality of test bodies containing the same metal as the high temperature member are unloaded in one of the test bodies in a high temperature atmosphere. Shows the test process of performing a heating test and performing a creep test on the other test body in a high temperature atmosphere, the test time required for the creep test of the other test body, and the time until the other test body breaks. The creep damage rate calculation step of calculating the creep damage rate from the ratio to the creep rupture time, and the one of the test pieces is used as an unloaded test piece and ultrasonic waves are radiated to the unloaded test piece to propagate the unloaded test piece. A fourth sound velocity value measuring step of measuring the velocity of ultrasonic waves as the sound velocity value of the unloaded test body, and irradiating the creep damage test body with ultrasonic waves as the creep damage test body of the other test body, Creep A fifth sound velocity value measuring step of measuring the velocity of ultrasonic waves propagating through the damage specimen as a sound velocity value of the creep damage specimen, and a ratio of the sound velocity value of the creep damage specimen and the sound velocity value of the unused material. And the ratio of the sound velocity value of the unloaded test body and the sound velocity value of the unused material is calculated by combining the heating test time of the creep damage test and the unloaded test body, respectively, and each calculated value in the same heating test time is calculated. A sound velocity ratio increase amount calculation step for calculating the sound velocity ratio increase amount from the difference, and a diagram showing a relationship between the creep damage ratio and the sound velocity ratio increase amount is generated from the creep damage ratio and the sound velocity ratio increase amount. A method of predicting the life of a high temperature member, which comprises: 4. The method of predicting the life of a high temperature member according to claim 1, 2 or 3, wherein the high temperature member is configured as a rotor or a casing of a steam turbine, and the high temperature member constituting the rotor is CrMoV forged steel. And a high temperature member constituting the casing is CrMoV forged steel or cast steel. 5. The method for predicting the life of a high temperature member according to claim 1, 2, 3 or 4, wherein the high temperature member is C: 0.01 to 0.4%, Ni: 3 % Or more, Cr: 8 to 13% or less, V: 1% or less, Nb: 0.
5% or less and N: 0.1% or less,
Mo: 3% or less, W: 1% or less, and at least one of them is included, or Ni: 3% or less, Cr: 8 to 13% or less, V: 1% or less, Nb: 0.
5% or less and N: 0.1% or less,
A method of predicting the life of a high temperature member, comprising at least one of Mo: 3% or less and W: 10% or less.