2025-01-21 ペンシルベニア州立大学(PennState)
＜関連情報＞
- https://www.psu.edu/news/engineering/story/getting-over-hump-improve-fuel-cell-manufacturing
- https://www.nature.com/articles/s41467-024-53888-w
高速レーザー溶接におけるハンピングのメカニズムと発生閾値の解明 Unveiling mechanisms and onset threshold of humping in high-speed laser welding
Zen-Hao Lai,Siguang Xu,Samuel J. Clark,Kamel Fezzaa & Jingjing Li
Nature Communications Published:05 November 2024
DOI:https://doi.org/10.1038/s41467-024-53888-w
Abstract
The fabrication of fuel cells relies on a rapid laser welding process. However, challenges arise with the occurrence of humping when the welding speed surpasses a critical threshold, which poses difficulties in achieving a smooth surface finish and a consistent weld strength. This study aims to elucidate the humping mechanisms by analyzing the morphology of molten pool and the characteristics of melt flow at varying welding speeds via in situ synchrotron high-speed X-ray imaging and computational fluid dynamics simulations. Our findings indicate that the short keyhole rear wall, the high backward melt velocity, and the prolonged tail of molten pool are the primary factors contributing to the onset of humping. Furthermore, a dimensionless humping index (<?XML:NAMESPACE PREFIX = “[default] http://www.w3.org/1998/Math/MathML” NS = “http://www.w3.org/1998/Math/MathML” />πh) was introduced, which successfully captured the onset threshold of humping across different literatures. This index not only provides a quantitative description of the humping formation tendency but also serves as a valuable tool for optimizing the laser welding process.
