Taking an AZ91D magnesium alloy as the research object, a three-dimensional
(3D) numerical model was established and simulated by simulation analysis
software. The effects of a rotating electromagnetic field (REMF), a pulsed
electromagnetic field (PEMF) and a rotating pulsed electromagnetic field
(R-PEMF) on the magnetic field and flow field of a metal melt were studied.
The simulation results show that a rotational force is generated on the
cross section of the melt during the REMF treatment, and the PEMF causes
magnetic pressure on the cross section of the melt. Under the combined
action of the two, the Lorentz force parallel to the melt axis increases,
and a secondary flow pointing to the core of the melt is generated, which
helps to homogenize the melt. By analyzing the solidification structure and
elemental distribution of the metal, it was shown that R-PEMF effectively
improved the solidification structure and macrosegregation of the Al in the
AZ91D magnesium alloy.