Development of Weld Cracking Susceptibility Evaluation Method Considering Strain Concentration Caused by Temperature Distribution and Microstructure

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05154
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: Osaka University
• Principal Investigator: okano shigetaka 大阪大学, 大学院工学研究科, 准教授 (00467531)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: プロセス－力学統合シミュレーション / ひずみ挙動 / その場観察技術 / 温度分布 / 微視組織 / 割れ感受性

Outline of Final Research Achievements

Using process-mechanics integrated welding simulation and in-situ observation techniques, we have successfully quantified the strain behavior during the melting and solidification process in the trans-varestraint test, and also evaluated strain behavior at the microstructural level using numerical simulations based on the phase-field method. Strain concentration behavior that may contribute to crack initiation was suggested in these investigations, and a good correspondence with the results of in-situ observation technique was confirmed for the former. In addition, by systematically evaluating the effects of welding conditions on strain concentration behavior, we clarified the welding condition factors that dominate strain concentration and proposed a method to evaluate the degree of strain concentration in a unified manner, and demonstrated the usefulness of this method.

Free Research Field

溶接力学

Academic Significance and Societal Importance of the Research Achievements

本研究によって，溶接中の温度分布や微視組織の影響で従来考えられていなかったひずみ集中が生じることが明らかになったことは、溶接時に生じ得る割れの発生防止に向けた材料や施工条件の選定のための評価試験方法に対する理解をより一層深化させるものであり、学術的に有意義である。一方で，溶接・接合技術はものづくりにおいて欠かせない重要な基盤技術の一つであり、本研究で得られた知見により今後のものづくり高度化や溶接構造物の信頼性・安全性向上に繋がると考えられるため，社会的にも有意義といえる。