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A multi-physics numerical model was developed to investigate the influence of a steady magnetic field during partial penetration keyhole laser beam welding of an aluminum plate in flat position.Three-dimensional heat transfer,fluid dynamics including phase transition and electromagnetic field partial differential equations were solved with the finite element differential equation solver COMSOL Multiphysics.The magnetic field was aligned perpendicularly to the welding direction.The main objective of these simulations was to estimate the critical value of the magnetic field needed to suppress convective flows in the weld pool during high-power(up to 20 kW)laser beam welding of aluminum alloys with up to 20 mm deep weld pool.It reveals that steady magnetic fields with corresponding Hartmann numbers Ha2-10~4based on the half-width of the weld pool can effectively suppress convective flows in the weld pool.Moreover,the typically occurring wineglass-shape of the weld cross section caused by thermo-capillary flow is weakened.
A multi-physics numerical model was developed to investigate the influence of a steady magnetic field during partial penetration keyhole laser beam welding of an aluminum plate in flat position. Three-dimensional heat transfer, fluid dynamics including phase transition and electromagnetic field partial differential equations were solved with the finite element differential equation solver COMSOL Multiphysics. The magnetic objective was aligned perpendicularly to the welding direction. Main objective of these simulations was to estimate the critical value of the magnetic field needed to suppress convective flows in the weld pool during high- power (up to 20 kW) laser beam welding of aluminum alloys up to 20 mm deep weld pool. It reveals that steady magnetic fields with corresponding Hartmann numbers Ha2-10 ~ 4b based on the half-width of the weld pool can behave suppress convective flows in the weld pool. Moreover, the typically occurring wineglass-shape of the weld cross section caused by thermo-capillary flow is weakened.