OBSERVATION OF MOLTEN STEEL FLOW IN SUBMERGED ENTRY NOZZLE

A fluid flow of molten steel in continuous casting mold directly results in slab surface and internal defects,such as slag entrapment, inclusions, and pinholes. Much effort was made on the field to stabilize it. Applicationof various electromagnetic forces and various nozzle designs are proposed and applied to commercialcontinuous casting process. However, few studies have looked at fluid flow in submerged entry nozzle even itis a source of flow in the mold.In this study, fluid flow in submerged entry nozzle is in-situ observed through transparent immersion nozzleby a fusible alloy model and a molten steel flow model. According to the experiment, fluid flow in submergedentry nozzle is dominated by argon flow rate, metal flow rate and nozzle diameter. Meniscus height in thenozzle is stable enough to measure, and decreasing argon flow rate, increasing metal flow rate and reducingnozzle diameter leads the flow from potential-flow to plug-flow.Another examination, measurement of net argon flow rate through mold meniscus revealed that about 20% ofargon gas injected from upper slide plate is brought into nozzle at continuous casting process. Taking theseresults into consideration, fluid flow in submerged entry nozzle in conventional slab caster is considered.