US 12,442,056 B2
High-strength galvanized steel sheet and member, and method for manufacturing same
Lingling Yang, Tokyo (JP); Yuki Toji, Tokyo (JP); Tomomi Kanazawa, Tokyo (JP); and Shunsuke Yamamoto, Tokyo (JP)
Assigned to JFE Steel Corporation, Tokyo (JP)
Appl. No. 18/568,407
Filed by JFE Steel Corporation, Tokyo (JP)
PCT Filed Mar. 18, 2022, PCT No. PCT/JP2022/012541
§ 371(c)(1), (2) Date Dec. 8, 2023,
PCT Pub. No. WO2022/264585, PCT Pub. Date Dec. 22, 2022.
Claims priority of application No. 2021-099666 (JP), filed on Jun. 15, 2021.
Prior Publication US 2024/0271243 A1, Aug. 15, 2024
Int. Cl. C21D 9/46 (2006.01); C21D 1/18 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01); C22C 38/10 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/34 (2006.01); C22C 38/38 (2006.01); C22C 38/60 (2006.01); C23C 2/02 (2006.01); C23C 2/06 (2006.01); C23C 2/28 (2006.01); C23C 2/40 (2006.01)
CPC C21D 9/46 (2013.01) [C21D 1/18 (2013.01); C21D 6/001 (2013.01); C21D 6/002 (2013.01); C21D 6/005 (2013.01); C21D 6/007 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 8/0257 (2013.01); C21D 8/0263 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/008 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/08 (2013.01); C22C 38/10 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C22C 38/34 (2013.01); C22C 38/38 (2013.01); C22C 38/60 (2013.01); C23C 2/022 (2022.08); C23C 2/06 (2013.01); C23C 2/28 (2013.01); C23C 2/40 (2013.01); C21D 2211/001 (2013.01); C21D 2211/002 (2013.01); C21D 2211/008 (2013.01); C22C 2202/02 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A high strength galvanized steel sheet comprising a steel sheet and a galvanizing layer and having a tensile strength of not less than 1,320 MPa,
wherein the steel sheet has a chemical composition containing, by mass,
C: 0.150 to 0.450%,
Si: 0.80 to 3.00%
Mn: 2.00 to 4.00%,
P: not more than 0.100%,
S: not more than 0.0200%,
Al: not more than 0.100%,
O: not more than 0.0100%, and
N: not more than 0.0100%,
with a balance of Fe and inevitable impurities, and
a microstructure,
an amount of diffusible hydrogen in the steel sheet is not more than 0.60 mass ppm, and
in the microstructure,
a total area fraction of tempered martensite and bainite is 60 to 95%,
an area fraction of retained austenite is 5 to 30%,
an area fraction of the retained austenite having an aspect ratio of 5.5 or higher with respect to a whole of the retained austenite is not more than 50%, and
an area fraction of fresh martensite having a diameter of 2.0 μm or less is not more than 20%.