MANUFACTURE OF STEEL PLATE FOR EXTREMELY DEEP DRAWING

摘要

PURPOSE:To obtain the titled steel plate having uniform quality, preventing cracking due to secondary working, and causing hardly powdering in the manufacture of a steel plate plated with alloyed zinc by adding restricted amounts of Ti and Nb to a steel having a specified composition, hot rolling and cold rolling the steel, and continuously annealing it. CONSTITUTION:A steel contg. =0.007% C, =0.8% Si, =1.0% Mn, =0.1% P, 0.01-0.1% Al, =80ppm N, Ti satisfying equations I , II, IV and 0.003-0.025% Nb satisfying equations III, IV is hot rolled, cold rolled, and continuously annealed at 700 deg.C- the Ac3 transformation point. N is precipitated as TiN in place of AlN before finish hot rolling, and C is precipitated as a composite carbide [Ti, Nb]C, so the desired steel plate is obtd.