| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-strength steel which has strength of 570 MPa or higher, high formability, and superior uniformity of the quality, and which can be manufactured without using tempering heat treatment and a special cooling condition, and has a reduced slitting-strain, and to provide a manufacturing method therefor. SOLUTION: The high-strength steel superior in the formability and the uniformity of the quality comprises, by mass%, 0.02-0.1% C, 0.6% or less Si, 0.5-2% Mn, 0.1-1.2% W, more than 0.05% but 0.2% or less Ti, 0-0.2% Nb and/or 0-0.1% V, and the balance substantially Fe; and has metallographic structure substantially consisting of a single phase of ferrite, and of carbides which include W, Ti, Nb and/or V, have grain sizes of less than 10 nm, and precipitate and disperse in the number of 80% or more with respect to that of all precipitates except TiN. COPYRIGHT: (C)2004,JPO
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