Improvement of Continuously Cast Slab Surface and Performance of Rolling the Slab Free from Surface Conditioning

Abstract

Refinement in operating practice and technical development such as degassing, Ar gas shrouding, mould fluxes, tundish refractories, slab surface temperature control in the secondary cooling zone and so on, made it possible to improve slab surface quality and hence reheat the slab without surface conditioning.
Recently, 80% of the slabs for plates and 50% for sheets are charged directly into the reheating furnaces by this process, with excellent results. On the basis of this development, continuous casting of high grade steels such as API-70 and deep drawing quality steels have been made possible.