Unveiling mechanisms and onset threshold of humping in high-speed laser welding
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 (pi h\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$$${\pi }_{h}$$$$\end{document}) 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. Humping defects in high-speed laser welding of stainless steel are investigated here using in situ synchrotron X-ray imaging and fluid dynamics simulations. High welding speeds cause a short keyhole rear wall, high backward melt velocity, and long molten pool tail, leading to humping.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- US Department of Energy; USDOE Office of Energy Efficiency and Renewable Energy (EERE) - Hydrogen and Fuel Cell Technologies Office (HFTO); USDOE Office of Science
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 2585183
- Journal Information:
- Nature Communications, Journal Name: Nature Communications Journal Issue: 1 Vol. 15; ISSN 2041-1723
- Country of Publication:
- United States
- Language:
- English
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