PURPOSE: To provide microstructure and mechanical properties homogeneous in the plate-thickness direction of a thick steel plate, by subjecting a carbon steel or low-alloy steel slab to cooling or to cooling after rolling to a slight extent and by subjecting the above to maintenance of temp. prior to control rolling so as to make the whole slab uniformly low-temp.
CONSTITUTION: The above slab is heated to a temp. between Ac3 point and 1,150°C, which is cooled in a state of a slab without application of rolling or is cooled after rolling to a thickness of intermediate stage. Cooling is stopped before the surface temp. drops below the Ar3 point, and the steel is successively maintained at a temp. of Ar3 point or above and lower than the heating temp. After that, rolling is started at a temp. of (maintenance temp. -70°C) or above, and rolling is carried out at and above the Ar3 point at 30W70% draft. In this way, difference in rolling temp. in the direction of plate thickness is removed and uniformization of material in the plate-thickness direction can be attained.
TOMITA YUKIO
YAMABA RYOTA
OOYAMA NOBORU
| JPS60258410A | 1985-12-20 | |||
| JPS6171105A | 1986-04-12 |