Engineering Study on Twin Roll and Thin Slab Caster

Abstract

This study introduces how to enhance the castability for near-net-shape casting especially for the Twin Roll strip Casting (TRC) and Thin slab Casting (TSC). The flow control of sump in the TRC is direct influence to the quality of products, so the design of the Submerged Entry Nozzle (SEN) which supply molten iron to the sump should be carefully determined. If the hole of SEN designed vertical downward, the molten iron flowed directly to the nip, then, almost one half of sump volume remained static and below solidus temperature. To solve this unexpected flow pattern, two types of horizontal SEN was investigated. One had holes, commonly used in the commercial plants, and the other had newly designed slits. However both of them had good flow patterns for solidification, the edge area still remained static. To stir this static flow, the Electromagnetic Stirring (EMS) was applied. EMS systems which were installed above the meniscus made induced magnetic field and current density to the sump. These generated Lorentz force and accelerated flow of the edge area. To ensure the even solidification of the shell for the TSC, the arrangement of coolant hole of funnel mold was investigated. There were dozens of coolant hole inside the mold, it was almost impossible to adjust each holes for even temperature distribution at the hot surface of the copper plate. To solve this problem, analyzing optimal heat transfer to the center profile of coolant hole was executed. The resultant optimal profile which remained smooth halved temperature deviation on the hot surface compared to the original design.