2021 Fiscal Year Final Research Report
Prevention of Hot Cracking by Thermal Strain Control using Laser Beam
| Project/Area Number |
18K13938
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 24020:Marine engineering-related
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| Research Institution | Osaka University |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2022-03-31
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| Keywords | 高温割れ / 凝固割れ / 割れ対策 / レーザ / 熱ひずみ制御 / 予測 / 数値解析 |
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| Outline of Final Research Achievements |
This study focused on the prevention of solidification cracking in welding. The solidification cracking is closely related to the thermal strain generated around the molten pool during welding. Therefore, we have proposed a method of preventing the solidification cracking by actively controlling the thermal strain using a welding system with a laser beam. The validity of this concept was demonstrated through the development of a numerical model to predict the solidification cracking occurrence, an optimization of laser irradiation conditions suitable for preventing the solidification cracking based on the numerical model, and an experimental verification of the optimized conditions. The results also showed that the use of a laser as an auxiliary heat source in welding can prevent solidification cracking, and that the auxiliary use of a laser and its additional value can be clarified for the laser, which is expected to be used as the main heat source in welding.
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| Free Research Field |
溶接技術，溶接冶金，金属材料
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| Academic Significance and Societal Importance of the Research Achievements |
凝固割れの対策として，レーザ補助照射による熱ひずみ制御が有効であることが示唆されたことは，材料学的対策や抜本的な施工プロセス（主熱源側など）の改善などで対策されてきた凝固割れ問題に対して，非常に有意義な課題解決策を提示したことになる．また，レーザ熱源の新たな活用方法が提案され，社会的意義は非常に大きい．凝固割れ発生の予測モデル化，そのコンセプトの妥当性を理論・実験の両面から示唆できたことは，学術的意義が大きい．生産技術の最適化に向けた数値シミュレーション活用の可能性を大きく示唆するものであり，学術に基づいて産業（ものづくり）の最適化につながる有意義な研究成果であると捉えることができる．
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