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Komine, Ryuji
PNC TN9450 96-017, 1183 Pages, 1999/01
In order to advancement in materials-strength standard on elevated temperature design guide of the Demonstration Fast Reactors and evaluation method of materials strength behavior, this report are presented about the tensile and Creep, fatigue and creep fatigue and relaxation test, effect properties of Mod.9Cr-1Mo steel, besed on the R&D result obtained through the activities of materials tests. Contents of the data sheet are as follows (1)Material ; Mod.9Cr-1Mo steel (Base metal.) (2)Test method and Number of data ;Tensile test 228 points ;Creep test 176 points ;Fatigue test 191 points ;Creep fatigue test 30 points ;Relaxation test 52 points (3)Environment ; in Air And thier data are arrangement by the stractural materials data system (SMAT).
Komine, Ryuji; Wada, Yusaku
PNC TN9410 98-086, 135 Pages, 1998/08
A sodium-water reaction drived from the single tube break in steam generator might overheat nabor tubes rapidly under internal pressure loadings. If the temperature of tube wall becomes too high, it has to be evaluated that the stress of tube does not exceed the material strength limit to prevent the propagation of tube rupture. In the present study this phenomenon was recognized as the fracture of cylindrical tube with the large deformation due to overheating, and the evaluation method was investigated based on both of experimental and analytical approaches. The results obtained are as follows. (1)As for the nominal stress estimation, it was clarified through the experimental data and the detailed FEM elasto-plastic large deformation analysis that the formula used in conventional designs can be applied. (2)Within the overheating temperature limits of tubes, the creep effect is dominant, even if the loading time is too short. So the strain rate on the basis of JIS elevated temperature tensile test method for steels and heat-resisting alloys is too late and almost of total strain is composed by creep one. As a result the time dependent effect cannot be evaluated under JIS strain rate condition. (3)Creep tests in shorter time condition than a few minutes and tensile tests in higher strain rate condition than 10%/min of JIS are carried out for 2.25Cr-1Mo(NT) steel, and the standard values for tube rupture strength evaluation are formulated. (4)The above evaluation method based on both of the stress estimation and the strength standard values application is justified by using the tube burst test data under internal pressure. (5)The strength standard values on Type 321 ss is formulated in accordance with the procedure applied for 2.25Cr-1Mo(NT) steel.
Sawada, Kota; Maruyama, Koichi; Komine, Ryuji; Nagae, Yuji
PNC TN9410 98-018, 32 Pages, 1998/02
Mod.9Cr-1Mo steel has a martensitic lath structure. Recovery of the lath structure takes place hl the course of creep. Microstructural degradation due to the recovery results in the acceleration of creep rate and the subsequent failure of a specimen. Change of lath width during creep of the steel was quantitatively investigated to propose a residual life assessment methodology based on the recovery process. Since the steel was tempered at 1053K, the lath structure is thermally stable at the testing temperatures (848K
923K). However, recovery of lath structure readily takes place during creep, indicating that the recovery is induced by creep deformation. Lath width 
increases with creep strain and saturates to a value 
determined by creep stress. The increase of is faster at a higher stress and temperature. A normalized ehange in lath width, 
/, was introduced to explain the variation of lath growth rate with creep stress and temperature. is the change in lath width from the initial value 
, and is the difference between and . / is uniquely related to creep strain 
and the relationship is independent of creep stress as well as ereep temperature. This /- relationship obtained by an accelerated creep test at a higher temperature or stress is applicable to any creep condition including service conditions of engineering plants. Creep strain can be evaluted from the measurement of / based on the /- relationship. A creep curve under any creep condition can readily be calculated by creep data of the steel. Combining these information one can assess residual life of a structural component made of the steel.
Sawada, Kota; Maruyama, Koichi; Komine, Ryuji; Nagae, Yuji
PNC TN9410 97-035, 41 Pages, 1997/03
Several microstructural changes take place in a material during the course of creep. These changes can be a measure of creep life consumption. In this paper, microstructural changes in Mod.9Cr-1Mo steel were studied in order to examine their ability as the measure of crecp life consumption. Macroscopic structural changes, such as void growth, rotation of lath structure toward the tensile axis and elongation of grains, are evident only in the necked portion of ruptured specimens. These macroscopic structural changes are not useful for creep life assessment. Lath width increases and dislocation density within lath decreases with increasing creep duration. These changes in dislocation substructure start in the early stage of creep life, and cause the increase of strain rate in the tertiary creep stage. The lath width and the dislocation density reach a stationary value before rupture. The stationary values are independent of temperature, and uniquely related to creep stress normalized by shear modulus. The extent of these microstructural changes are greater at lower stresses under which the material is practically used. These facts suggest that the lath width and the dislocation density within lath can be a useful measure of creep life consumption. Hardness of crept specimens is closely related to the lath width and the dislocation density within lath. The changes of these microstructural features can be evaluated by the measurement of handness.
Sawada, Kota*; Maruyama, Koichi*; Komine, Ryuji; Nagae, Yuji
Tetsu To Hagane, 83(7), p.466 - 471, 1997/00
None
Watashi, Katsumi; Aoto, Kazumi; Aoki, M; Komine, Ryuji; Ito, Takushi; Hasebe, Shinichi; Kato, Shoichi; Koi, Mamoru; Wada, Yusaku
PNC TN9410 93-142, 120 Pages, 1993/06
Much progress has been made in improving established creep properties of Type 316 stainless steel and to develop a new structural material named "FBR Grade Type 316 Stainless Steel", 316FR, with superior creep properties. This report includes a draft of Material Strength Standard of 316FR and its interpretation on the basis of the major result of research and development conducted so far. The draft includes identical items described in the "Standards for the Strength of Materials" for Monju, and was carefully prepared to have an identical style for convenience in design evaluation. Creep damage evaluation diagrams, which are depicted in the "Structural Design Guide for Class 1 Components of Prototype Fast Breeder Reactor for Elevated Temperature Service" (ETSDG) for individual materials, are also included in this report.
