| 摘要 |
PROBLEM TO BE SOLVED: To produce a thin steel sheet having sufficient formability applicable to forming for parts for car body structure and capable of easily obtaining high strength by hardening after the forming, and to provide a method for producing the same. SOLUTION: This thin steel sheet is the one in which the steel has a compsn. contg., by weight, 0.05 to 0.20% C, <=0.1% Si 0.8 to 2.0% Mn, <=0.02% P, <=0.02% S, <=0.005% N, 0.0003 to 0.004% B and 0.01 to 0.10% sol.Al also so as to satisfy sol.Al(%)>=9.6×N(%) and Ti in the range of <=3.4×N(%), and the balance Fe with inevitable impurities. The method for producing the thin steel sheet is the one in which a steel slab having this compsn. is hot-rolled, is formed into a hot-rolled coil at >=600 deg.C coiling temp. or is formed into a hot rolled coil at >=480 deg.C coiling temp., is thereafter cold-rolled and is annealed.
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