| 摘要 |
PROBLEM TO BE SOLVED: To provide a high tensile strength cold rolled steel sheet which is suitable for uses yielding complicated cross-sectional shape on pressing, can be galvanized, has excellent elongation and stretch-flanging properties serving as indexes of workability and has a tensile strength of≥550 MPa, to provide a production method thereof, and to provide a working method thereof. SOLUTION: The high tensile strength steel sheet has a composition containing, by weight, >0.01 to 0.1% C,≤0.3% Si, 0.2 to 2.0% Mn,≤0.04% P,≤0.02% S,≤0.1% Al,≤0.006% N and 0.03 to 0.2% Ti, and containing one or more kinds of metals selected from≤0.5% Mo and≤1.0% W, and the balance substantially Fe. The steel sheet has a structure consisting substantially of a ferritic single phase, and carbides of <10 nm satisfying, by atom, 0.5≤C/(Ti+Mo+W)≤1.5 are dispersed therein. COPYRIGHT: (C)2004,JPO
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