Ferritic stainless steel having improved corrosion resistance, and manufacturing method therefor
AssigneePosco
InventorsKwang Min Kim, Kkoch Nim Oh, Dong-Hoon Kim
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Abstract
Disclosed is a ferritic stainless steel with improved corrosion resistance. The ferritic stainless steel with improved corrosion resistance according to an embodiment of the present disclosure includes, 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: 0.3% or less (excluding 0), Cr: 16 to 20%, Ni: 0.4% or less (excluding 0), the remainder of iron (Fe) and other inevitable impurities, and a Cr weight % content of a thickness region from a surface of a passivation film to 3 nm is 1.2 times or more than the Cr weight % content of the stainless base material.
Claims12
A ferritic stainless steel with improved corrosion resistance 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:
- 0.3% or less (excluding 0), Cr:
- 16 to 20%, Ni:
- 0.4% or less (excluding 0), the remainder of iron (Fe) and other inevitable impurities;
- and
- a passivation film formed on the stainless base material, and
- wherein the Cr weight % content of the thickness region from the surface of the passivation film to 3 nm is 1.2 times or more than the Cr weight % content of the stainless base material.
A manufacturing method of a ferritic stainless steel with improved corrosion resistance, the manufacturing method comprising:
- manufacturing a stainless steel 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:
- 0.3% or less (excluding 0), Cr:
- 16 to 20%, Ni:
4% or less (excluding 0), the remainder of iron (Fe) and other inevitable impurities;
- forming a chromium-enriched layer on a surface of the stainless steel;
- and
- immersing in nitric acid or mixed acid solution comprising nitric acid and hydrofluoric acid.
Dependencies are inferred from the claim text.