FERRITIC STEEL SHEET EXCELLENT IN STRAIN RATE DEPENDENCE, AND AUTOMOBILE USING SAME

摘要

PROBLEM TO BE SOLVED: To provide a ferritic steel sheet capable of statically strengthening the conventional steel sheet and further preventing reduction in the amount of increase in dynamic strength. SOLUTION: This ferritic steel sheet excellent in dependence on strain rate contains, by mass, 0.01-4.0%, in total, of Co and/or Cr in a state of solid solution in ferritic phase. The steel sheet has a composition consisting of, by mass, 0.0001-0.05% C, 0.01-1.0% Si, 0.01-2.0% Mn, =0.15% P, =0.03% S, 0.01-0.1% Al, =0.01% N, =0.007% O, and the balance iron with inevitable impurities and further containing one or =2 kinds among =0.20% Ti, =0.20% Nb, and =0.005% B.