| 摘要 |
PROBLEM TO BE SOLVED: To provide a high strength steel sheet which has excellent workability and satisfactory bake hardenability. SOLUTION: The high strength steel sheet contains, by mass, 0.06 to 0.25% C, 0.5 to 3% Si+Al, 0.5 to 3% Mn,≤0.15% (exclusive of 0%) P and≤0.02% (exclusive of 0%) S. The structure of the matrix phase consists of tempered martensite or tempered bainite, and the space factor thereof is≥50% to the whole structure, or the space factor of tempered martensite or tempered bainite is≥15% to the whole structure, and ferrite is also contained; in the second phase structure, the space factor of retained austenite is 3 to 30% to the whole structure; and further, bainite or martensite can be contained. Also, its bake hardening (BH) satisfies BH (2%)≥70 MPa, and BH (10%)≥BH (2%)/2. COPYRIGHT: (C)2004,JPO
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