JP4028276B2 - Method for evaluating changes in material properties of stainless steel members - Google Patents
Method for evaluating changes in material properties of stainless steel members Download PDFInfo
- Publication number
- JP4028276B2 JP4028276B2 JP2002099514A JP2002099514A JP4028276B2 JP 4028276 B2 JP4028276 B2 JP 4028276B2 JP 2002099514 A JP2002099514 A JP 2002099514A JP 2002099514 A JP2002099514 A JP 2002099514A JP 4028276 B2 JP4028276 B2 JP 4028276B2
- Authority
- JP
- Japan
- Prior art keywords
- stainless steel
- value
- mechanical property
- temperature
- change
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は原子力プラント等の特に高温で長期間使用される部材に用いられるステンレス鋼等の材料の機械的特性値の経年変化を予測する方法に関する。
【０００２】
【従来の技術】
従来の原子力プラント等においてマルテンサイト系ステンレス鋼および析出硬化型ステンレス鋼は高強度で耐食性に優れることから、各種弁の弁棒、回転機軸材等の腐食環境中で高応力を要求される部材に多用されている。また、フェライト系ステンレス鋼、オーステナイト−フェライト系ステンレス鋼は耐食性・加工性に優れることから、熱交換器の伝熱管等に使用されている。
【０００３】
いくつかの研究により、マルテンサイト系ステンレス鋼、析出硬化型ステンレス鋼およびオーステナイト−フェライト系ステンレス鋼は高温に長時間加熱されると硬さの上昇、靱性、延性の低下および応力腐食割れ感受性の増大等を生じることが明らかになった。
【０００４】
上記研究の報告の例として、文献例１："Thermal Aging Behavior of Martensitic Stainless Steel" M.Tsubota, K.Tajima, K.Hattori, H.Sakamoto、International Nuclear Power Plant Aging Symposium, USNRC, Bethesda, Maryland, Aug. 30, (1988)、文献例２："Characterization of Long Term Aged Martensitic Stainless Steels" M.Tsubota, K.Hattori, T.Okada, 5th International Symposium on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactor, Montrey, California, Aug. 30, (1991)、文献例３："Aging Degradation of Cast Stainless Steels" O.K.Chopra and H.M.Chung, Environmental Degradation of Materials in Nuclear Power Systems-Water Reactor, (1988)がある。
【０００５】
【発明が解決しようとする課題】
しかしながら、これらステンレス鋼部材を高温において長時間使用した場合の機械的特性値の変化や応力腐食割れ感受性がどの程度かわかっていない。使用中のステンレス鋼部材の機械的特性値の変化や応力腐食割れ感受性の予測が可能であれば、部材の脆化または応力腐食割れに基づく破損を防止することができ、機器の信頼性向上につながる。
本発明の目的は、使用中のステンレス鋼等の部材の機械的特性値を評価する方法を提供することにある。
【０００６】
【課題を解決するための手段】
本発明は上記目的を達成するものであって、請求項１の発明は、原子力プラント等で使用中のステンレス鋼部材と同等の材料の機械的特性値の経年変化曲線を当該機械的特性値の初期値と温度と時間の関数（Ｉ）としてあらかじめ求めておき、前記ステンレス鋼部材の機械的特性値の初期値と温度と時間から、前記関数（Ｉ）に基づいて当該部材の機械的特性値を求めるステンレス鋼部材の材料特性変化評価方法において、熱活性化過程に基づくステンレス鋼のスピノーダル分解の活性化エネルギＱを少なくとも２種類の温度における前記ステンレス鋼部材と同等の材料の機械的特性値の経年変化曲線から求めることを特徴とする。
ｔ＝Ａ・ｅｘｐ（Ｑ／ＲＴ）……関数（Ｉ）
ここで、ｔは時間、Ｔは温度、Ａは定数、Ｒは気体定数、Ｑは活性化エネルギ
請求項１の発明によれば、部材の機械的特性値の変化を非破壊的に予測または評価することができる。
【００１４】
また、請求項２の発明は、請求項１に記載のステンレス鋼部材の材料特性変化評価方法において、前記機械的特性値の限界値をあらかじめ設定し、前記機械的特性値が前記限界値に到達する時点を前記部材の寿命と設定し、前記機械的特性値の経年変化曲線に基づいて、前記寿命に到達する時間を推定すること、を特徴とする。
請求項２の発明によれば、請求項１の発明の作用・効果を得られるのみならず、使用中の部材の寿命を推定することができる。
【００１５】
また、請求項３の発明は、請求項１又は２に記載のステンレス鋼部材の材料特性変化評価方法において、前記機械的特性値は、硬さ、耐力、引張強さ、伸び、絞り、衝撃値および破壊靭性値のうちの少なくとも一つであること、を特徴とする。
【００１６】
請求項３の発明によれば、請求項１又は２の発明の作用・効果を得られるのみならず、ステンレス鋼部材について、機械的特性値として具体的に種々のものを採用することができる。
【００２１】
【発明の実施の形態】
［第１の実施の形態］
マルテンサイト系、析出硬化系、フェライト系およびオーステナイトーフェライト系ステンレス鋼に生じる劣化挙動は、組織中のマルテンサイト相およびフェライト相が長時間加熱されることによりＦｅ原子とＣｒ原子が周期的に分離する相分離、つまり、Ｆｅリッチ相とＣｒリッチ相に分離するスピノーダル分解と呼ばれる現象によるものである。このスピノーダル分解は熱活性化過程であることから、分解に必要な温度Ｔと時間ｔの関係は式（１）で記述される。
ｔ＝Ａ・ｅｘｐ（Ｑ／ＲＴ）……（１）
ここで、Ａは定数、Ｒは気体定数、Ｑは活性化エネルギである。
【００２２】
機械的特性変化の推定曲線を得るには図１（ａ）に示すように、指標とする機械的特性Ｐの変化を異なった複数の温度（例えばＴ1，Ｔ２）で採取する。変化する機械的特性Ｐを初期値Ｐｏで除し、温度Ｔ1とＴ２における経年変化推定曲線(図１（ｂ）)を得る。ここで、Ｐ／Ｐｏは経年変化度αである。経年変化度αに対しては、式（１）が成り立つことから、それぞれの温度において次の式（２）、（３）が成り立つ。
【００２３】
ｔ1＝Ａ・ｅｘｐ（Ｑ／ＲＴ1）……（２）
ｔ2＝Ａ・ｅｘｐ（Ｑ／ＲＴ2）……（３）
式（２）、（３）から、この経年変化事象に関する活性化エネルギＱが求まる。
【００２４】
Ｑ＝Ｒ（log t1−log t2）／（1／T1−1／T2）……（４）
得られたＱと経年変化度推定曲線０（図１（ｃ））とから、実際に測定していない温度（Ｔ3）における経年変化度αに対応する時間が、式（５）によって求まる。
log t0 = log t3 − (Q／R)(1／T3−1／T0)……（５）
【００２５】
上述のようにマルテンサイト系、フェライト系等のステンレス鋼のスピノーダル分解の活性化エネルギＱを用いることによって、あらゆる温度条件における経年変化推定曲線を得ることが可能である。したがって、図２に示すように経年変化推定曲線が求まっている材料においては、使用温度（例えばＴ3）、使用時間（例えばｔ3）に対応した経年変化度α3が決定できる。経年変化度α3を入力された初期特性値Ｐｏに乗じ、ｔ3時間使用後の特性値Ｐを算出する。
【００２６】
なお、以上述べた各種データの処理や保存等に電子計算機を使えば能率よく行えることはいうまでもない。
また、上記説明はステンレス鋼について行なったが、式（１）が成り立つ材料であれば、本発明の適用は、ステンレス鋼に限定されるものではない。
【００２７】
［第２の実施の形態］
本発明の第２の実施の形態では、機械的特性および応力腐食割れ感受性の指標として硬さを用いる。
【００２８】
機械的特性、例えば引張強さ、衝撃値、破壊靭性値等はいずれも破壊試験が必要であり、当該部品を損傷無しに測定することはできない。ここで、硬さと他の機械的特性値（例えば耐力、引張強さ、衝撃値、破壊靭性値等）は一般的に相関性があることから、あらかじめ硬さと他の機械的特性の相関を求めておけば、硬さを他の機械的特性値の指標とすることが可能である。
【００２９】
さらに、図３に示すように、応力腐食割れ感受性と硬さの間に相関があることもわかっており、硬さは応力腐食割れ感受性の指標としても使用可能である。また、図４に示すように使用中の硬さを予測することで、他の材料特性値を予測することができる。
【００３０】
［第３の実施の形態］
本発明の第３の実施の形態では、上述した第１の実施の形態からさらに図５に示すように求められた特性値Ｐと予め定められた限界値Ｐｃとの大小を比較し、特性値Ｐが限界値Ｐｃ以上となったときに当該部材は寿命に達したと推定すること寿命予測することができることである。
【００３１】
［第４の実施の形態］
本発明の第４の実施の形態では、図６に示すように硬さ測定結果からオンラインで他の機械的特性値の予測を可能とする。超音波式等の携帯用硬さ測定器と計算機を接続し、あらかじめ対象材料の機械的特性値の経年変化推定曲線等の必要なデータを計算機に入力し、第２の実施の形態をシステムとして入力しておくことで、硬さ測定とともに瞬時に他の機械的特性値の予測および応力腐食割れ感受性の有無を判定することができる。また、計算機に第３の発明の形態をシステムとして入力しておくことで、硬さ測定とともに瞬時に寿命予測をすることもできる。
【００３２】
［第５の実施の形態］
本発明の第５の実施の形態では、図７に示すように機器の使用温度が不明な場合に硬さ測定結果と運転時間から使用温度を推定する。機器によっては、使用温度が明確でない場合もある。第２あるいは第４の実施の形態で示した硬さ測定が可能な部材においては、初期値Ｐｏ、測定値Ｐ、使用時間ｔおよび活性化エネルギＱと硬さの経年変化推定曲線から使用温度Ｔを推定することができる。ただし、温度履歴に変化があった場合においても使用時間中、一定の温度で使用していたとして推定される。
【００３３】
【発明の効果】
以上説明したように、本発明によれば、ステンレス鋼等の部材の運転時間、運転温度および初期値がわかれば現在の機械的特性値を予測でき、その部材を使用した機器の機械的特性値の予測および寿命予測が可能となる。また、請求項５の発明によれば、現在の硬さ測定値に基づいて使用温度を推測することができる。
【図面の簡単な説明】
【図１】本発明における機械的特性変化推定曲線の求め方を示す説明図であって、（ａ）は温度Ｔ1およびＴ２における機械的特性Ｐの変化の例を表すグラフ、（ｂ）は（ａ）の機械的特性Ｐを初期値Ｐｏで除した値（経年変化度α）の変化を表すグラフ、（ｃ）は温度０における機械的特性変化の経年変化度の推定曲線を表すグラフ。
【図２】本発明に係る機械的特性変化予測方法の第１の実施の形態の手順を示す流れ図。
【図３】硬さと応力腐食割れ感受性の相関性を示す特性図。
【図４】本発明に係る機械的特性変化予測方法の第２の実施の形態の手順を示す流れ図。
【図５】本発明に係る機械的特性変化予測方法の第３の実施の形態の手順を示す流れ図。
【図６】本発明に係る機械的特性変化予測方法の第４の実施の形態の手順を示す流れ図。
【図７】本発明に係る第５の実施の形態の部材使用温度推定方法の手順を示す流れ図。
【符号の説明】
０…機械的特性変化の変化度推定曲線（温度Ｔ０）、１…機械的特性変化（温度Ｔ１）、２…機械的特性変化（温度Ｔ２）、１１…機械的特性変化度（温度Ｔ１）、１２…機械的特性変化度（温度Ｔ２）、２１…機械的特性変化の推定曲線（温度Ｔ３）。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to how to predict the particular aging in the mechanical characteristic value of the material of stainless steel or the like used for members that are used for a long time at high temperatures, such as nuclear power plants.
[0002]
[Prior art]
In conventional nuclear power plants, martensitic stainless steels and precipitation hardened stainless steels have high strength and excellent corrosion resistance. Therefore, they are suitable for parts that require high stress in corrosive environments such as valve stems and shafts of rotary machines. It is used a lot. Ferritic stainless steel and austenitic-ferritic stainless steel are used in heat exchanger tubes of heat exchangers because they are excellent in corrosion resistance and workability.
[0003]
Several studies have shown that martensitic stainless steels, precipitation hardened stainless steels and austenitic-ferritic stainless steels have increased hardness, reduced toughness, reduced ductility and increased stress corrosion cracking susceptibility when heated to high temperatures for extended periods of time. It became clear that it produces.
[0004]
As an example of the above research report, Reference Example 1: “Thermal Aging Behavior of Martensitic Stainless Steel” M. Tsubota, K. Tajima, K. Hattori, H. Sakamoto, International Nuclear Power Plant Aging Symposium, USNRC, Bethesda, Maryland, Aug. 30, (1988), Reference Example 2: “Characterization of Long Term Aged Martensitic Stainless Steels” M. Tsubota, K. Hattori, T. Okada, 5th International Symposium on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactor, Montrey, California, Aug. 30, (1991), Reference Example 3: “Aging Degradation of Cast Stainless Steels”, OKChopra and HM Chung, Environmental Degradation of Materials in Nuclear Power Systems-Water Reactor, (1988).
[0005]
[Problems to be solved by the invention]
However, it is not known to what extent the change in mechanical property values and the sensitivity to stress corrosion cracking when these stainless steel members are used at high temperatures for a long time. If it is possible to predict changes in mechanical property values and stress corrosion cracking susceptibility of stainless steel members in use, it is possible to prevent the material from becoming brittle or damaged due to stress corrosion cracking, and to improve the reliability of equipment. Connected.
An object of the present invention is to provide a way of evaluating the mechanical characteristic values of the stainless steel or the like in use.
[0006]
[Means for Solving the Problems]
The present invention achieves the above-mentioned object, and the invention of
t = A · exp (Q / RT) …… Function (I)
Here, t is time, T is temperature, A is a constant, R is a gas constant, and Q is activation energy. According to the invention of
[0014]
The invention of
According to the invention of
[0015]
Further, the invention of
[0016]
According to the invention of
[0021]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
The deterioration behavior of martensitic, precipitation hardened, ferritic and austenitic ferritic stainless steels is caused by periodic separation of Fe and Cr atoms by heating the martensitic and ferritic phases in the structure for a long time. This is due to phase separation that occurs, that is, a phenomenon called spinodal decomposition that separates into an Fe-rich phase and a Cr-rich phase. Since this spinodal decomposition is a thermal activation process, the relationship between the temperature T and the time t required for the decomposition is described by equation (1).
t = A · exp (Q / RT) (1)
Here, A is a constant, R is a gas constant, and Q is activation energy.
[0022]
In order to obtain an estimated curve of the mechanical characteristic change, as shown in FIG. 1A, the change of the mechanical characteristic P as an index is sampled at a plurality of different temperatures (for example, T 1 and T 2 ). The changing mechanical characteristic P is divided by the initial value Po to obtain a secular change estimation curve (FIG. 1B) at the temperatures T 1 and T 2 . Here, P / Po is the aging degree α. Since the equation (1) holds for the aging degree α, the following equations (2) and (3) hold at each temperature.
[0023]
t 1 = A · exp (Q / RT 1 ) (2)
t 2 = A · exp (Q / RT 2 ) (3)
From equations (2) and (3), the activation energy Q relating to this aging event is obtained.
[0024]
Q = R (log t 1 −log t 2 ) / (1 / T 1 −1 / T 2 ) (4)
From the obtained Q and the aging estimation curve 0 (FIG. 1 (c)), the time corresponding to the aging α at the temperature (T 3 ) that is not actually measured is obtained by Equation (5).
log t 0 = log t 3 − (Q / R) (1 / T 3 −1 / T 0 ) (5)
[0025]
As described above, by using the activation energy Q of spinodal decomposition of stainless steel such as martensite and ferrite, it is possible to obtain a secular change estimation curve under all temperature conditions. Therefore, as shown in FIG. 2, in the material for which the secular change estimation curve is obtained, the secular change degree α 3 corresponding to the use temperature (for example, T 3 ) and the use time (for example, t 3 ) can be determined. A characteristic value P after use for t 3 hours is calculated by multiplying the input initial characteristic value Po by the degree of aging α 3 .
[0026]
Incidentally, it can be performed better efficiency With more mentioned computer processing and storage of various data of course.
Moreover, although the said description was performed about stainless steel, if it is a material with which Formula (1) is materialized, application of this invention is not limited to stainless steel.
[0027]
[Second Embodiment]
In the second embodiment of the present invention, hardness is used as an index of mechanical characteristics and stress corrosion cracking sensitivity.
[0028]
Mechanical properties such as tensile strength, impact value, fracture toughness value, etc. all require a destructive test, and the part cannot be measured without damage. Here, hardness and other mechanical property values (for example, yield strength, tensile strength, impact value, fracture toughness value, etc.) are generally correlated, so the correlation between hardness and other mechanical properties is obtained in advance. In this case, the hardness can be used as an index of other mechanical characteristic values.
[0029]
Furthermore, as shown in FIG. 3, it is also known that there is a correlation between the stress corrosion cracking sensitivity and the hardness, and the hardness can be used as an index of the stress corrosion cracking sensitivity. Moreover, other material characteristic values can be predicted by predicting the hardness in use as shown in FIG.
[0030]
[Third Embodiment]
In the third embodiment of the present invention, the characteristic value P obtained from the first embodiment described above is further compared with the predetermined limit value Pc as shown in FIG. When P becomes equal to or greater than the limit value Pc, it can be estimated that the member has reached the end of its life.
[0031]
[Fourth Embodiment]
In the fourth embodiment of the present invention, other mechanical characteristic values can be predicted online from the hardness measurement result as shown in FIG. Connect a portable hardness measuring instrument such as an ultrasonic type to a computer, and input necessary data such as the secular change estimation curve of the mechanical property value of the target material into the computer in advance, and the second embodiment as a system By inputting, it is possible to instantaneously predict other mechanical characteristic values and determine the presence or absence of stress corrosion cracking susceptibility together with the hardness measurement. Further, by inputting the form of the third invention as a system to the computer, it is possible to instantaneously predict the life together with the hardness measurement.
[0032]
[Fifth Embodiment]
In the fifth embodiment of the present invention, as shown in FIG. 7, when the operating temperature of the device is unknown, the operating temperature is estimated from the hardness measurement result and the operation time. Depending on the device, the operating temperature may not be clear. In the member capable of measuring the hardness shown in the second or fourth embodiment, the use temperature T is determined from the initial value Po, the measurement value P, the use time t, the activation energy Q, and the hardness secular change estimation curve. Can be estimated. However, even when there is a change in the temperature history, it is estimated that the temperature is being used at a constant temperature during the usage time.
[0033]
【The invention's effect】
As described above, according to the present invention, if the operation time, operation temperature and initial value of a member such as stainless steel are known, the current mechanical property value can be predicted, and the mechanical property value of the equipment using the member Prediction and lifetime prediction are possible. According to the invention of claim 5, the operating temperature can be estimated based on the current hardness measurement value.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing how to obtain a mechanical characteristic change estimation curve according to the present invention, wherein (a) is a graph showing an example of changes in mechanical characteristics P at temperatures T 1 and T 2 ; Is a graph showing a change in a value (aging degree α) obtained by dividing the mechanical characteristic P of (a) by an initial value Po, and (c) is a graph showing an estimated curve of the changing degree of mechanical characteristic change at a temperature of 0. .
FIG. 2 is a flowchart showing the procedure of the first embodiment of the mechanical property change prediction method according to the present invention;
FIG. 3 is a characteristic diagram showing the correlation between hardness and stress corrosion cracking susceptibility.
FIG. 4 is a flowchart showing a procedure of a second embodiment of a mechanical property change prediction method according to the present invention.
FIG. 5 is a flowchart showing the procedure of a third embodiment of a mechanical property change prediction method according to the present invention;
FIG. 6 is a flowchart showing the procedure of a fourth embodiment of a mechanical property change prediction method according to the present invention;
FIG. 7 is a flowchart showing a procedure of a member use temperature estimation method according to a fifth embodiment of the present invention.
[Explanation of symbols]
0 ... mechanical characteristic change of change of the estimated curve (
Claims (3)
ｔ＝Ａ・ｅｘｐ（Ｑ／ＲＴ）……関数（Ｉ）
ここで、ｔは時間、Ｔは温度、Ａは定数、Ｒは気体定数、Ｑは活性化エネルギ An aging curve of mechanical property values of a material equivalent to a stainless steel member used in a nuclear power plant or the like is obtained in advance as a function (I) of the initial value of the mechanical property value and temperature and time, and the stainless steel In the method for evaluating the material property change of a stainless steel member that obtains the mechanical property value of the member based on the function (I) from the initial value, temperature, and time of the mechanical property value of the member, material properties change evaluation method for stainless steel member characterized by determining from the aging curves of the mechanical characteristic value of the stainless steel member and equivalent material activation energy Q of spinodal decomposition of the steel in at least two temperatures.
t = A · exp (Q / RT) …… Function (I)
Where t is time, T is temperature, A is a constant, R is a gas constant, and Q is activation energy.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002099514A JP4028276B2 (en) | 2002-04-02 | 2002-04-02 | Method for evaluating changes in material properties of stainless steel members |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002099514A JP4028276B2 (en) | 2002-04-02 | 2002-04-02 | Method for evaluating changes in material properties of stainless steel members |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2003294605A JP2003294605A (en) | 2003-10-15 |
| JP4028276B2 true JP4028276B2 (en) | 2007-12-26 |
Family
ID=29240922
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002099514A Expired - Fee Related JP4028276B2 (en) | 2002-04-02 | 2002-04-02 | Method for evaluating changes in material properties of stainless steel members |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4028276B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5239179B2 (en) * | 2007-03-13 | 2013-07-17 | 独立行政法人産業技術総合研究所 | Back pressure valve |
| JP5931381B2 (en) * | 2011-09-13 | 2016-06-08 | 三菱日立パワーシステムズ株式会社 | Damage evaluation method and maintenance evaluation index formulation method |
| CN103852411B (en) * | 2012-12-04 | 2016-05-04 | 天津市电力公司 | Pyrocondensation insulating materials operation aging assessment |
| CN114279944B (en) * | 2021-12-23 | 2023-05-30 | 苏州热工研究院有限公司 | Method for evaluating coupling effect of heat aging, stress and corrosion of stainless steel welding material |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56163437A (en) * | 1980-05-21 | 1981-12-16 | Ishikawajima Harima Heavy Ind Co Ltd | Method for quantitatively determining degree of sensitization of stainless steel |
| JPH01284732A (en) * | 1988-05-10 | 1989-11-16 | Mitsubishi Heavy Ind Ltd | Evaluating method for creep life expectancy of high temperature equipment |
| JPH07119755B2 (en) * | 1989-10-06 | 1995-12-20 | 株式会社日立製作所 | Simple deterioration determination method and device |
| EP0443260A1 (en) * | 1990-02-16 | 1991-08-28 | Westinghouse Electric Corporation | Method for determining an equivalent average temperature associated with the thermal history of equipment |
| JPH05113397A (en) * | 1991-10-22 | 1993-05-07 | Babcock Hitachi Kk | Method and apparatus for estimating corrosion of metal material |
| JP3045626B2 (en) * | 1993-05-18 | 2000-05-29 | 関西電力株式会社 | Degradation diagnosis method for laminated products |
| JP3920961B2 (en) * | 1996-04-03 | 2007-05-30 | 九州電力株式会社 | Evaluation method of remaining life of low alloy steel |
-
2002
- 2002-04-02 JP JP2002099514A patent/JP4028276B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2003294605A (en) | 2003-10-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zhang et al. | P92 steel creep-fatigue interaction responses under hybrid stress-strain controlled loading and a life prediction model | |
| CN107843510B (en) | Method for estimating residual endurance life of supercritical unit T/P91 heat-resistant steel based on room-temperature Brinell hardness prediction | |
| CN103063528A (en) | Method for fast evaluating high temperate member residual service life on spot | |
| JP5931283B2 (en) | Method for nondestructive evaluation of intergranular stress corrosion cracking (IGSSC) in structural elements made of metal alloys, and method for evaluating the lifetime of structural elements | |
| Du et al. | A new energy‐based method to evaluate low‐cycle fatigue damage of AISI H11 at elevated temperature | |
| Li et al. | Physically-based modeling of cyclic softening and damage behaviors for a martensitic turbine rotor material at elevated temperature | |
| Hayhurst et al. | Constitutive equations for time independent plasticity and creep of 316 stainless steel at 550 C | |
| JP4028276B2 (en) | Method for evaluating changes in material properties of stainless steel members | |
| Kim et al. | Electrochemical noise analysis of PbSCC of Alloy 600 SG tube in caustic environments at high temperature | |
| Li et al. | A novel fatigue-oxidation-creep life prediction method under non-proportional loading | |
| Kawaguchi et al. | Prediction method of tensile properties and fracture toughness of thermal aged cast duplex stainless steel piping | |
| Masuyama | Advances in creep damage/life assessment technology for creep strength enhanced ferritic steels | |
| Li et al. | Cumulative damage model based on equivalent fatigue under multiaxial thermomechanical random loading | |
| CN111859619B (en) | Nondestructive prediction method for low cycle fatigue life of heat aging material by using hardness | |
| Cheng et al. | Geometric discontinuity effect on creep-fatigue behaviors in a nickel-based superalloy hole structure considering ratcheting deformation | |
| JP2012108051A (en) | Method of predicting damage in heat-resistant steel weld zone | |
| Riley et al. | Prediction and validation of multi-axial stress state effects on creep failure of pre-compressed 316H stainless steel | |
| JP2002340784A (en) | Method and system for managing life of structural member | |
| Kim et al. | Improved methodology for determining tensile elastic and plastic strain components of Alloy 617 | |
| Wei et al. | A New Linear Superposition Theory and its Application in Creep Fatigue-Oxidation Crack Growth Modeling | |
| Joyce | On the utilization of high rate pre-cracked charpy test results and the master curve to obtain accurate lower bound toughness predictions in the ductile-to-brittle transition | |
| Acosta et al. | Microstructure-based Lifetime Assessment of Austenitic Steel AISI 347 Exposed to Corrosion and Fatigue | |
| Bucher et al. | Elasto-viscoplastic behavior of the ferritic stainless steel AISI 441-EN 1.4509 from room temperature to 850 C | |
| JP5555560B2 (en) | Structural material integrity evaluation method and program | |
| Woodford et al. | Creep strength evaluation of serviced and rejuvenated T91 using the stress relaxation method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20041130 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20060707 |
|
| RD04 | Notification of resignation of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7424 Effective date: 20060823 |
|
| RD02 | Notification of acceptance of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7422 Effective date: 20070220 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070626 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20070824 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20071002 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20071011 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101019 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101019 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111019 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111019 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121019 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131019 Year of fee payment: 6 |
|
| LAPS | Cancellation because of no payment of annual fees |