Experimental and Numerical Study on Fluid Flow and Heat Transfer in Siphon Continuous Casting Process

Abstract

In the continuous casting process, controlling molten steel flow in the mold is one of the most important factors, because it is directly related to both productivity and quality.Most of the quality problems in the continuous casting process are originated from the high discharging velocity at the SEN exit

normally it is more than 60 times faster compared to the casting speed. This relatively high SEN discharging velocity deteriorates not only the meniscus stability but also the flotation of inclusions and bubbles in the mold. The higher casting speed, the more severe fluid flow related problems are emerged, which is the major obstacle to the high productivity.In this study, as a new concept, siphon tundish that is a technique of pouring liquid steel into mold by employing siphon principle is proposed to overcome the several problems of continuous casting process. Because the small level difference between tundish and mold level makes small pressure drop as a driving force, siphon casting process can be designed to have a large nozzle area, which means it has slow nozzle outlet velocity. Water model experiment and numerical simulation are conducted for siphon tundish as comparing the result from conventional casting process. Experimental result shows that siphon tundish shows very stable meniscus and uniform nozzle outlet profile. Numerical simulation was done for various geometries to compare the bubble floatation property and temperature distribution. Siphon nozzle shows good bubble floatation due to the reduced nozzle outlet velocity. In case of meniscus temperature, geometrical change can provide the sufficient temperature at meniscus.