Research on the Surface Quality of Momentum‐Flow Twin‐Roll Strip Casting Strip Based on Numerical Simulation

We have developed a twin‐roll strip caster utilizing momentum‐flow technology (MF‐TRC) and established a two‐dimensional numerical model of fluid flow and heat transfer in the molten pool using the commercial software Fluent. Combined with MF‐TRC experiments, the mechanism of strip surface morphology formation under different processing conditions was investigated. The results show that casting speed is the decisive factor in determining the strip exit deceleration rate. A low roll speed leads to a high kiss point (KP) height, which increases the separation force when the strip detaches from the roll gap, resulting in transverse wrinkles on the strip surface and even leading to card‐rolling accidents. Conversely, an excessively high roll speed suppresses KP formation. Another key factor causing strip wrinkling is the entrapment of bubbles and oxides. The sources of liquid‐level fluctuations mainly come from two aspects: the magnitude of the net flow rate during the filling process and flow disturbances at steady state. As the net flow rate increases, bubble entrainment first decreases and then increases. In addition, reducing flow fluctuations can effectively suppress bubble entrapment, and sudden drops in mass flow have a greater impact on molten pool liquid‐level fluctuations than sudden increases.