Isothermal Modeling of Meniscus Oscillation in the Continuous Strip Casting Process

In the continuous strip casting process a meniscus forms a compliant boundary between the casting nozzle and transporting conveyor. Movement of this meniscus during casting has been shown to create surface defects, which require extensive cold work to remove and limit the minimum thickness for which sections may be cast. This paper discusses experimental work conducted to test an analytical model of the meniscus oscillation. A high frame rate shadowgraph technique was used on an isothermal water model of the casting process to observe meniscus motion, and thus allow the calculation of meniscus frequency, amplitude, contact points and contact angles. Both natural frequency and flow excited tests were conducted. Natural frequency tests were also conducted using mercury which has a nonwetting contact angle typical of molten metals. The experimental results were found to be in good agreement with the predictions of theory for both wetting and nonwetting conditions. The experimentally verified analytical model for meniscus motion is valuable to the design of a continuous casting process because it describes the effect of geometrical parameters on meniscus motion and thus provides an opportunity to mitigate the effects of boundary motion on surface quality.