	US 12,188,104 B2
	Steel sheet for a structure with excellent seawater corrosion resistance and method of manufacturing same
Jin-Ho Park, Pohang-si (KR)
Assigned to POSCO, Pohang-si (KR)
Appl. No. 17/782,913
Filed by POSCO, Pohang-si (KR)
PCT Filed Nov. 27, 2020, PCT No. PCT/KR2020/017131 § 371(c)(1), (2) Date Jun. 6, 2022, PCT Pub. No. WO2021/118128, PCT Pub. Date Jun. 17, 2021.
Claims priority of application No. 10-2019-0163090 (KR), filed on Dec. 9, 2019.
Prior Publication US 2023/0026116 A1, Jan. 26, 2023
Int. Cl. C21D 9/46 (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 38/42 (2006.01); C22C 38/50 (2006.01)

CPC C21D 9/46 (2013.01) [C21D 8/0226 (2013.01); C21D 8/0263 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/42 (2013.01); C22C 38/50 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01); C21D 2211/009 (2013.01)]

7 Claims

1. A steel sheet for a structure comprising, by weight, carbon (C): 0.03% or more to less than 0.1%, silicon (Si): 0.1% or more to less than 0.8%, manganese (Mn): 0.3% or more to less than 1.5%, chromium (Cr): 0.5% or more to less than 1.5%, copper (Cu): 0.1% or more to less than 0.5%, aluminum (Al): 0.01% or more to less than 0.08%, titanium (Ti): 0.005% or more to less than 0.1%, nickel (Ni): 0.05% or more to less than 0.1%, phosphorus (P): 0.03% or less, sulfur (S): 0.02% or less, and a balance of iron (Fe) and unavoidable impurities,

a microstructure of an entire steel sheet is 20% or more of bainite, less than 80% of polygonal ferrite and acicular ferrite in total, and 15% or less of pearlite and MA as the other phases, by area fraction, and

variations of tensile strength between both end portions of the steel sheet in length direction are 50 MPa or less.