To improve the energy saving effect by raising a cast slab temperature at the charging into a heating furnace when a thick steel plate is manufactured from the continuously cast slab with a rolling mill in the hot-charge.
The cast slab 1 having unsolidified phase 2 in the inner part is forcibly cooled in a continuous caster and this surface temperature is lowered to ≤500°C and also, kept to ≤500°C for ≥15 sec. Then, the cast slab is solidified to the center part thereof while recuperating the heat on the surface of the cast slab and thereafter, the high temperature cast slab cut to a prescribed length is charged into the heating furnace, and after heating into a prescribed temperature, the hot-rolling is executed to manufacture the thick steel plate. At this time, it is desirable to make ≥5% unsolidified phase ratio of the cast slab when this is forcibly cooled, to recuperate the heat by keeping the temperature of the cast slab and to forcibly cool the cast slab after passing through a lower straightening zone in the continuous caster in the case of using a vertical and bending type continuous caster.
AWAJIYA HIROSHI
KOBAYASHI KAZUTAKA
KAMIOKA SATOSHI
