Abstract
Aluminum alloys are the materials which face difficulties in weldability. One of solutions to increase the weldability of aluminum alloys is removing the oxide-layer on the surface of aluminum by adopting variable polarity arc welding. The authors’ previous experimental research about variable polarity arc welding of aluminum showed that reverse arc polarity has larger heat input efficiency than straight polarity. In this study, numerical analysis of molten pool in aluminum alloy by variable polarity GTAW has been introduced and developed. The arc heat source, arc pressure, electromagnetic force and Marangoni flow regarding the variable polarity GTAW have been applied as the boundary conditions and body force terms. Governing equations such as the conservation of the mass, momentum and energy are numerically solved to derive temperature and flow vector field. Additionally, volume of fluid method is adopted to track free surface of molten pool and it was implemented through using commercial package Flow-3D. Through the present analysis, mathematical model for variable polarity arc is newly suggested and following result successfully showed effect of different heat input efficiency for each straight and reverse polarity. The heat input efficiencies are arbitrarily decided here for feasibility but a methodology to numerically determine the exact value is suggested. The final goal of these research series is to determine the heat input efficiency of reverse polarity arc aluminum welding indirectly through simulation and experiment comparison.
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Recommended by Associate Editor Young Whan Park
Jungho Cho received his Ph.D. at KAIST in 2007 and now he is a faculty of Chungbuk National University after working at Hyundai Motors for several years. His major is development of welding and joining techniques, welding physics and thermo-dynamical analysis of weld pool.
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Jeong, H., Park, K. & Cho, J. Numerical analysis of variable polarity arc weld pool. J Mech Sci Technol 30, 4307–4313 (2016). https://doi.org/10.1007/s12206-016-0845-7
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DOI: https://doi.org/10.1007/s12206-016-0845-7