Flow Instabilities in the Horizontal Single Belt Casting Process with an Inclined Feeding System

Abstract

Both physical experiments and mathematical simulations were employed to investigate the transport phenomena involved during Horizontal Single Belt Casting (HSBC) of AA6111 aluminum alloy, using an inclined feeding system. Flow instabilities in the metal delivery system were first analyzed, and it was found that the first impingement gives rise to instabilities in the melt film falling from the slot nozzle of the head box. Meanwhile, this impingement also has the potential to result in air suction. Using the Eulerian multiphase method, the start casting stage is shown to be very short. Its predictions are similar to those from the Volume of Fluid (VOF) method, and both are confirmed by physical experiments. During steady state casting, one can classify the melt into four regions. The “wavy contour” in “Region I” is an instability largely induced by impingement on an inclined refractory piece. “Region II” demonstrates the buffer effect of the inclined refractory wall and the flow must be continuous within it. The resistance force induced by the melt that has flowed just earlier onto the belt, gives rise to “Region III”, which is a transition region. Its transient variations in width determine the quality of the strip’s edges. The thickness of “Region IV” is associated with both “Region II” and “Region III”.