| Project/Area Number |
24560879
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | Osaka University |
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Principal Investigator |
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| Project Period (FY) |
2012-04-01 – 2015-03-31
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| Project Status |
Completed (Fiscal Year 2014)
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| Budget Amount *help |
¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000)
Fiscal Year 2014: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2013: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2012: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
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| Keywords | 溶接 / 溶接熱影響部 / M-A組織 / き裂 / 有効結晶粒 / じん性 / 相変態 / 高張力鋼 / 大入熱溶接 / き裂進展 / 結晶方位解析 / 相安定性 / ベインゾーン / 最密面グループ / 残留オーステナイトの炭素濃度 / 残留オーステナイトの相安定性 / 高強度鋼 / 組織形態 / 結晶学的特徴 / 破壊単位の結晶学的解析 / 組織変化 / 組織予測 |
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| Outline of Final Research Achievements |
In simulated HAZ of high-strength steel simulating high heat input welding,
it was clarified that phase stability of retained-austenite in M-A constituent was high when it was formed between bainitic ferrite laths of same variant. By using bright X-ray diffraction analysis, the carbon content of stable retained-austenite was quantified as 1.0 mass%. On the other hand, its stability was low when retained-austenite was formed between different variants. Furthermore, to assess the relation among M-A constituent, matrix microstructure and toughness, resistance due to the microstructural factor against cleavage crack extension was visualized using EBSD analysis. For the crack extension, both of Bain zone boundaries and boundaries of close-packed plane group were resistance. Furthermore, M-A constituent easily formed at boundaries of close-packed plane group was also resistance. Those facts were visualized by analyzing the secondary crack extension in simulated HAZ of high-strength steel.
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