| 摘要 |
PURPOSE:To obtain non-ageing galvanized sheet having high ductility and super deep drawability by limiting the additive quantities of Cr, Ti and Nb and also specifying cold rolling and annealing conditions. CONSTITUTION:A composition consists of, by weight, 0.001-0.01% C, <=0.1% Si, <=0.5% Mn, 0.01-0.10% Sol.Al, 0.06-0.20% Cr, <=0.03% P, <=0.015% S, <=0.007% N, <=0.01% O, and the balance Fe with inevitable impurities, and further contains Ti so that (available Ti quantity) represented by an equation is 4XC%-0.15% and also contains Nb so that Nb quantity is <=0.05% and simultaneously satisfies (available Ti quantity)+Nb<=0.20%. A steel slab with the above composition is hot-rolled and then cold-rolled at >=40% draft, and the obtained steel strip is passed through an inline annealing type continuous zinc hot dipping apparatus, where the steel strip is subjected to continuous annealing at the temp. between the recrystallization temp. and 900 deg.C and then to zinc hot dipping treatment.
|
