Mechanism investigation of the influence of the magnetic field on the molten pool behavior during laser welding of aluminum alloy. (December 2020)

• Record Type: Journal Article
• Authors: Cao, Longchao; Zhou, Qi; Liu, Huaping; Li, Jingchang; Wang, Shengyi
• Is Part Of: International journal of heat and mass transfer. Volume 162(2020)
• Publication Date: 2020-12
• Subjects: Magnetic field-assisted welding -- Molten pool flow -- Weld bead shape -- Numerical simulation -- Laser welding; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2020.120390
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: A full factorial experiment of the magnetic assisted-laser welding was conducted. The dynamic keyhole, the molten pool, and the magnetic field are incorporated. The weld bead shape was affected by the magnetic field. The maximum Lorentz force can reach 6.7 × 10 5 N /m 3 under a magnetic field of 420 mT. The molten flow and the heat transfer are suppressed by the magnetic field. Abstract: Magnetic field-assisted welding provides a promising approach to suppress defects and improve weld bead properties significantly. In this paper, a full factorial experiment was conducted to study the mechanism of the influence of the magnetic field on the weld profile of aluminum alloy laser welding. Furthermore, a three-dimensional numerical simulation model simultaneously considering the free surface of the keyhole, and the effect of the magnetic field is developed to reveal the mechanism of the influence of the magnetic field on the weld bead profile by analyzing molten pool behavior. It was found that the magnetic field can reduce the width of the weld bead while increasing the depth and middle width of the weld bead. The magnetic field distribution in the weld bead was numerically simulated and validated. The simulation results demonstrate that the liquid motion in the magnetic field can induce a Lorentz force in a direction opposite to the flow velocity. The magnetic field can suppress both the lower-to-upper region and center-to-edge molten flows of the molten pool, which reduces the heat transfer from the tip of the keyhole to the molten pool surface and from the center to the boundary of the molten pool. This can provide a concept to reveal the underlying mechanism of the influence of the magnetic field on the weld bead profile. This work could contribute to gain insight into the influence of a magnetic field on aluminum alloy laser welding.