| Project/Area Number |
11555026
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Tohoku University |
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Principal Investigator |
HASHIDA Toshiyuki Tohoku Univ., Graduate school of Eng., Prof., 大学院・工学研究科, 教授 (40180814)
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| Co-Investigator(Kenkyū-buntansha) |
KOMAZAKI Shin-ichi Dept. Matls. Sci. and Engrg., Muroran Inst. Tech., Research Associate, 材料物性工学科, 助手 (70315646)
KAWASAKI Akira Tohoku Univ., Graduate school of Eng., Prof., 大学院・工学研究科, 教授 (50177664)
SHOJI Tetsuo Tohoku Univ., Graduate school of Eng., Prof., 大学院・工学研究科, 教授 (80091700)
OKADA Ikuo Mitsubishi Heavy Industries, Ltd., Takasago R&B Center, Chief Engineer, 高砂研究所, 主任(研究職)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥13,700,000 (Direct Cost: ¥13,700,000)
Fiscal Year 2001: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1999: ¥10,300,000 (Direct Cost: ¥10,300,000)
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| Keywords | Small Punch Creep Testing / Gas Turbine / Boiler / High Temperature Materials / Creep Deformation Rate / Biaxial Deformation / Creep Deterioration / Larson-Miller Parameters / ラーソン-ミラーパラメーター |
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| Research Abstract |
A small punch creep (SP-C) testing method using a miniaturized specimen with a dimension of 10mm by 10mm by 0.3mm has been demonstrated for evaluating creep properties and mechanical deterioration due to long-term service operations at high temperatures. This testing method involves the application of a concentrated central load to the specimen rigidly supported at its surrounding region, and determines a central deformation vs. time curve for a given load and temperature. The SP-C method was applied to several types of high temperature boiler and turbine materials, including tungsten-alloyed 9Cr ferritic steel, 316 type stainless steel, and Ni-based super alloys. Experimental results revealed that the overall shapes of the creep curves obtained SP-C tests were qualitatively similar to those obtained from conventional uniaxial creep tests, which clearly delineate primary, secondary, and tertiary creep stages. Bending was a dominant mode of deformation governing the primary creep region, while membrane stretching was dominant mode in the secondary and tertiary creep regions. A correlation with uniaxial creep was determined in terms of stress (load) exponent and apparent activation energy for creep deformation. In particular, the apparent activation energy obtained from the SP-C method was close to that determined from uniaxial creep tests. The rupture data was deduced from the SP-C tests conducted on the used materials using the Larson-Miller parameters. The results demonstrated that the SP-C testing method enables us to determine the effects of the high temperature materials degradation on the creep properties. The above experimental evidence suggests that the SP-C testing technique provides a useful tool for evaluating degradation of creep properties for structural components in-service.
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