PURPOSE: To produce a homogeneous and good-quality steel sheet by specifying the wt.% of the C, Si, Mn, N, Al, Ti, and Nb of steel, hot-working the steel in a specified temp. range, dipping the steel in a salt bath at a specified temp., and hot-working the steel deposited with the molten salt under specified conditions.
CONSTITUTION: The steel to be used contains, by weight, ≤0.05% C, 0.005W1% Si, 0.005W1% Mn, ≤0.01% N, and ≥1 kind among ≤0.01% Al, ≤0.2% Ti, and ≤0.1% Nb. While the steel is cooled from a temp. higher than its Ar3 point, the steel is hot-worked by ≥50% for ≤1 sec in the temp. range from the Ar3 point to 1000°C. The steel is then dipped in a salt bath at 250W750°C, and the steel deposited with the molten salt is hot-rolled at ≥50% draft at 250W750°C. The steel is then heated at a temp. higher than 500°C and lower than the Ac1 point. By this method, a homogeneous and good-quality steel sheet can be produced.
SENUMA TAKEHIDE
HAMAUZU SHUICHI
