Abstract
Muroran Works of Nippon Steel Corp. formerly sized continuously cast slabs at a breakdown mill before transfer to the hot strip mill. Slabs must be continuously cast with such a width as required by the hot strip mill if they are to be sent directly to the hot strip mill without sizing.
When slabs of a given width were continuously cast at a high speed, the width fluctuates greatly at the exit of caster and sometimes exceeds the allowable slab width at the hot strip mill.
Muroran Works developed a constant slab width control model that uses a width changing device to minimize the slab width fluctuation at the continuous caster; a hot slab width meter of the contact type that can level the edge profile of slab to increase the allowable range of slab width at the hot strip mill; and a roughing edger setup model that can make the most of the small capacity of the roughing edger at the hot strip mill.
As a result, it became possible to supply the hot strip mill with slabs directly from the continuous caster when a powerful vertical scalebreaker or sizing mill is not available. The models and instruments developed are described.
