Penetration Shape Improvement and Investigation of its Mechanism in Workpiece Vibration Assisted Gas Metal Arc Welding

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04677
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26030:Composite materials and interfaces-related
• Research Institution: Osaka University
• Principal Investigator: Ito Kazuhiro 大阪大学, 接合科学研究所, 教授 (60303856)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: ガスメタルアーク溶接 / ダンデムトーチ / 溶込み形状 / 被溶接体正弦波振動 / 溶融池流体計算 / マランゴニ対流 / 実効入熱

Outline of Final Research Achievements

It was discovered that a workpiece sine-mode vibration transposed the finger-shape into pan-bottom penetration in tandem-pulsed gas metal arc welding. The competition between the heat distribution beneath the surface and the physical movement caused by the workpiece sine-mode vibration are traced. It is found that applying the vibration extends the heat distribution along the welding direction beneath the weld pool surface, and this trend increases with increasing vibration frequency and effective heat input. In contrast, the heat extending is minimum in the sample without vibration having the highest heat input. This inconsistency can be explained by the physical movement of material in a molten pool due to the workpiece vibration. The vibration also changes the material flow from the surface to the depth in the central rear areas, although it follows an opposite direction in the sample without vibration. Thus, the material flow is vital in improving the penetration shape.

Free Research Field

接合・溶接

Academic Significance and Societal Importance of the Research Achievements

溶融池内のマランゴニ対流により、ダンデムガスメタルアーク溶接の特徴であるアーク直下が深い異方的なフィンガー形状の溶け込み形状を、なべ底型に変化させられることを初めて見出したことが、学術的、産業的に大きなインパクトを与えた。解明した機構からも明らかなように、ある特異な条件下で発現する現象であったためこれまで知られていなかったと思われる。特異な条件下であるが、主なポイントはこのような振動が実効入熱を下げられることと、その溶融池温度中に表面張力の温度依存性の2階微分の変曲点が存在することであり、施工のおいて調整可能である。