| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacture of a steel sheet for two-piece modified can, capable of bulge forming at >=10% tensile strain in a circumferential direction after deep drawing. SOLUTION: A slab of a steel, having a composition containing, by weight, <=0.0020% C, <=0.05% Si, <=0.7% Mn, <=0.02% P, <=0.010% S, <=0.100% Al, 0.0030% N, and 0.003-0.03% Nb, is used. This steel slab is hot-rolled at >=850 deg.C finish rolling temp., coiled at >=650 deg.C, cold-rolled at >=85% draft, and annealed in the temp. range between the recrystallization temp. and 850 deg.C. The resultant steel sheet is temper-rolled at <=5% draft. By this method, the steel sheet, which has a structure composed of ferritic structure of <=15μm crystalline grain size and has >=1.8 average r-value and -0.10 to 0.10 anisotropy of r-value (Δr) and in which elongations in a rolling direction, in a direction perpendicular to the rolling direction, and in a direction at an angle of 45 deg. with respect to the rolling direction are regulated to >=40% respectively, and also an aging index (Al) is regulated to <=0.0 kgf/mm<2> , can be obtained.
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