Numerical simulation of the twin-roll casting process of magnesium alloy strip

The magnesium twin-roll strip casting process is investigated with a test caster at the IME. The flow field in the melt cannot be investigated optically, therefore numerical simulations have been undertaken to show the flow field in the Mg melt, the solidification between the two rolls and the cooling of the strip. The three-dimensional, turbulent flow field for different steady state casting points, in the process gap, have been calculated, including the solidification of the magnesium alloy melt. Within the process gap of the casting process the flow field shows similar flow structures. A big vortex in the casting channel and a much smaller vortex between the two rolls occur. With the increase of the casting speed the mushy zone is moved towards the kissing point. This can be interpreted due to a smaller force on the rolls. Nevertheless, the solidification on the rolls is so strong, that rolling between the two rolls happens.