PURPOSE: To obtain a continuously cast-and cold-rolled steel plate for working having excellent material quality free from rough surfaces, etc. by casting low Al, N steel of limited compsns. continuously, and hot-rolling the same at specific temp. then subjecting the same to cold rolling and box annealing.
CONSTITUTION: The steel contg. 0.03W0.07% C, 0.22W0.35% Mn and Al, N in the range enclosed by the coordinate points a, b, c, d, e, f, g, h shown by (p) in the figure, and consisting of the balance Fe with unavoidable impurities is cast cntinuously. This high temp. ingot is hot-rolled at temp. higher than the Ar3 point directly or after heat retaining or lightly heating stages. The hot-rolled steel strip is cold-rolled after descaling and is subjected to prescribed box annealing. According to such method, the decrease in yield owing to formation of abnormally coarse particles in the stage of box annealing is small and the continuously cast and cold-rolled steel plate for working having excellent material quality is obtained at low costs.
SATOU TOYOHIKO
SAITOU KIYOSHI
WAKABAYASHI SHIGEKI
