	US 12,247,309 B2
	Ferritic stainless steel having improved corrosion resistance, and manufacturing method therefor
Kwang Min Kim, Pohang-si (KR); Kkoch Nim Oh, Gwangju (KR); and Dong-Hoon Kim, Pohang-si (KR)
Assigned to POSCO CO., LTD, Pohang-si (KR)
Appl. No. 17/296,300
Filed by POSCO, Pohang-si (KR)
PCT Filed Nov. 1, 2019, PCT No. PCT/KR2019/014743 § 371(c)(1), (2) Date May 24, 2021, PCT Pub. No. WO2020/111546, PCT Pub. Date Jun. 4, 2020.
Claims priority of application No. 10-2018-0151017 (KR), filed on Nov. 29, 2018.
Prior Publication US 2022/0010451 A1, Jan. 13, 2022
Int. Cl. C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); C25D 11/38 (2006.01)

CPC C25D 11/38 (2013.01) [C22C 38/001 (2013.01); C22C 38/004 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01)]

10 Claims

1. A ferritic stainless steel comprising:

a stainless base material comprising, in percent (%) by weight of the entire composition,

C: 0.02% or less (excluding 0),

N: 0.02% or less (excluding 0),

Si: 0.5% or less (excluding 0),

Mn: 0.2% to 0.3%,

Cr: 16% to 20%,

Ni: 0.2% to 0.4%, and

the remainder of iron (Fe) and inevitable impurities; and

a passivation film formed on the stainless base material, and

wherein a Cr weight % content of a thickness region from a surface of the passivation film to 3 nm is 1.2 times or more than the Cr weight % content of the stainless base material.