| Project/Area Number |
18K18947
|
|---|
| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
|
| Allocation Type | Multi-year Fund |
|---|
| Review Section |
Medium-sized Section 26:Materials engineering and related fields
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
Nagira Tomoya 大阪大学, 接合科学研究所, 准教授 (00379124)
|
|---|
| Project Period (FY) |
2018-06-29 – 2020-03-31
|
| Project Status |
Completed (Fiscal Year 2019)
|
| Budget Amount *help |
¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Fiscal Year 2019: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Fiscal Year 2018: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
|
|---|
| Keywords | アーク溶接 / 凝固割れ / その場観察 / 放射光 / X線イメージング |
|---|
| Outline of Final Research Achievements |
The microstructural evolutions of solidification cracking at the weld crater and the weld bead were sucessffully observed in situ using time-resolved X-ray imaging. The local strain and strain rate in the parallel to the growth direction were highly localized and increased as the solidification progressed.The solidification cracking was linearly formed at the weld bead whereas the cracking was propagated to the different directions through the triple point at the weld crater. The shear strain contributed to the solidification cracking as well as the tensile strain. The tip velocity of the solidification cracking was periodically changed at the weld crater. Based on these findings, the microstructre was closely related to the solidification cracking.
|
| Academic Significance and Societal Importance of the Research Achievements |
凝固後の組織、モデル材料、シミュレーションを用いて組織形成を予測する従来手法では、実験による妥当性の検証が必要である。本研究では、放射光X線イメージングによるその場観察により、アーク溶接時に発生する凝固割れの形成機構を明らかにすることが出来た。凝固割れの臨界のひずみ、ひずみ速度、固相率などの従来手法では得られない定量データは、新たな物理モデルの構築やシミュレーションへの応用など学術的意義がある。また、本課題で取り上げるアーク溶接時での凝固割れは、実際の生産現場で直面している問題であり、凝固割れの予測や低減のための組織制御手法の提案など、基礎的な指針を提案できるとして工業的に重要な意義がある。
|
