scholarly journals A remaining life prediction method on the basis of micro-crack initiation and growth behavior under creep-fatigue in plain specimen of 316 stainless steel.

1986 ◽  
Vol 35 (389) ◽  
pp. 170-175 ◽  
Author(s):  
Shigeo SAKURAI ◽  
Saburo USAMI ◽  
Sadao UMEZAWA ◽  
Hiroshi MIYATA
1998 ◽  
Vol 120 (2) ◽  
pp. 119-125 ◽  
Author(s):  
Yukio Takahashi

Low-carbon, medium-nitrogen 316 stainless steel is a principal candidate for a main structural material of a demonstration fast breeder reactor plant in Japan. A number of long-term creep tests and creep-fatigue tests have been conducting for two heats of the steel. Two representative creep-fatigue life prediction methods, i.e., time fraction rule and ductility exhaustion method were applied. An introduction of a simple viscous strain term improved the description of stress relaxation behavior and only the conventional (primary plus secondary) creep strain was assumed to contribute to creep damage in the ductility exhaustion method. The present ductility exhaustion approach was found to have very good accuracy in creep-fatigue life prediction, while the time fraction rule overpredicted failure life as large as a factor of 30.


1999 ◽  
Vol 121 (2) ◽  
pp. 142-148 ◽  
Author(s):  
Y. Takahashi

Low-carbon, medium-nitrogen 316 stainless steel is a principal candidate for a main structural material of a demonstration fast breeder reactor plant in Japan. A number of long-term creep tests and creep-fatigue tests have been conducted for four products of this steel. Two representative creep-fatigue life prediction methods, i.e., time fraction rule and ductility exhaustion method were applied. Total stress relaxation behavior was simulated well by an addition of a viscous strain term to the conventional (primary plus secondary) creep strain, but only the letter was assumed to contribute to creep damage in the ductility exhaustion method. The present ductility exhaustion approach was found to have very good accuracy in creep-fatigue life prediction for all materials tested, while the time fraction rule tended to overpredict failure life as large as a factor of 30. Discussion was made on the reason for this notable difference.


1986 ◽  
Vol 35 (389) ◽  
pp. 176-182 ◽  
Author(s):  
Koichi YAGI ◽  
Osamu KANEMARU ◽  
Kiyoshi KUBO ◽  
Chiaki TANAKA

Author(s):  
J. Kusumoto ◽  
H. Watanabe ◽  
A. Kanaya ◽  
K. Ichikawa ◽  
S. Sakurai

In order to develop the life prediction method under creep-fatigue loading for gas turbine combustion transition piece, creep-fatigue tests were carried out on both as-received and aged Ni-based superalloy Nimonic 263. Crack initiation and propagation behaviors for the smooth specimen were observed. An unique relationship was obtained between life fraction and the maximum surface crack length under triangular wave shape loading tests, except the results for the trapezoidal wave loading tests. The latter results were due to the over estimation of the surface crack length at the crack initiation. These were caused from an oxide film break during straining. In the case of removing the oxide film before the measurement of surface crack, the relationship between life fraction and the maximum surface crack length obtained as unique relationship regardless of triangular and trapezoidal strain wave shapes. Using the life prediction method proposed, which is based on maximum surface crack length, the damage of combustion transition piece materials in service was evaluated.


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