| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel sheet for hot press, which has proper strength and high ductility in combination, and as a result, is suitably used for machine structural components including automotive body structural components and frame dress up parts. SOLUTION: The steel sheet for hot press has a chemical composition containing 0.15 to 0.45% C, 0.5 to 3.0% Mn+Cr, ≤0.05% P, ≤0.03% S, ≤0.5% Si and ≤1% Al, has a steel structure where carbides are dispersed into ferrite, wherein the average grain diameter D (μm) of the ferrite is 3 to 13 μm, the average opening intervals λ (μm) of dispersed carbides is ≤5 μm, and D<90λ<SP>2</SP>is satisfied, and further has such mechanical properties that 0.2% proof stress is 310 to 400 MPa, tensile strength is ≥400 MPa, uniform elongation is ≥12% and total elongation is ≥20%. COPYRIGHT: (C)2010,JPO&INPIT |
