Title:
GALVANNEALED STEEL SHEET AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2016/199922
Kind Code:
A1
Abstract:
A galvannealed steel sheet in which a galvannealing layer is provided on a surface of a steel sheet, wherein the chemical composition of the steel sheet in terms of mass% is 0.25-0.70% C, 0.25-2.50% Si, 1.00-5.00% Mn, 0.005-3.50% Al, 0.15% or less of P, 0.03% or less of S, ≤ 0.02% of N, and ≤ 0.01% of O and includes one or more species selected from Ti, Nb, V, Cr, Mo, Cu, Ni, B, Ca, REM, Mg, W, Zr, Sb, Sn, As, Te, Y, Hf, and Co as needed, the remainder being Fe and unavoidable impurities, the metallographic structure of the steel sheet in terms of vol% is 10.0-60.0% residual γ, ≥ 5.0% high-temperature tempered martensite, ≥ 5.0% low-temperature tempered martensite, ≤ 10.0% fresh martensite, 0-15.0% α, and 0-10.0% P, the remainder being bainite, and the total volume fraction of tempered martensite and bainite is 30.0% or greater, the tensile strength is 1470 MPa or greater, the product of the tensile strength and the average elongation is 13000 MPa% or greater, and the product of the tensile strength and the local elongation is 5000 MPa% or greater.
Inventors:
SANO KOHICHI (JP)
HAGA JUN (JP)
HAYASHI KOUTAROU (JP)
KAWATA HIROYUKI (JP)
OKAMOTO RIKI (JP)
UENISHI AKIHIRO (JP)
HAGA JUN (JP)
HAYASHI KOUTAROU (JP)
KAWATA HIROYUKI (JP)
OKAMOTO RIKI (JP)
UENISHI AKIHIRO (JP)
Application Number:
PCT/JP2016/067448
Publication Date:
December 15, 2016
Filing Date:
June 10, 2016
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
C22C38/00; C21D9/46; C22C18/00; C22C38/60
Domestic Patent References:
| WO2013047830A1 | 2013-04-04 | |||
| WO2013047755A1 | 2013-04-04 |
Other References:
See also references of EP 3309273A4
Attorney, Agent or Firm:
BRIGHTAS IP ATTORNEYS (JP)
patent business corporation Bligh -- TASS (JP)
patent business corporation Bligh -- TASS (JP)
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