Austenitic stainless steel and tube
AssigneeNippon Steel Corporation
InventorsMasahiro Seto, Takumi Nishimoto, Katsuki Tanaka
Life of this patent
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Abstract
There is provided an austenitic stainless steel having a chemical composition that comprises, in mass %: C: 0.002 to 0.020%, Si: 0.10 to 0.60%, Mn: 0.2 to 2.0%, P: 0.035% or less, S: 0.010% or less, Cu: 2.50 to 4.50%, Ni: 9.00 to 16.00%, Cr: 15.00 to 20.00%, Mo: 0.20 to 1.50%, Nb: 0.15 to 0.60%, N: 0.05 to 0.15%, B: 0.0010 to 0.0060%, and optional elements, with the balance: Fe and impurities and that satisfies [0.010≤VER+TiER+NbER], [27.0≤1.13(Ni—NiER)+(Cr—CrER)+1.85(Mo—MoER)+1.79(Nb—NbER)<40.5], and [NbER<0.052].
Claims8
An austenitic stainless steel having a chemical composition comprising, in mass %:
- C:
- 0.002 to 0.020%,
- Si:
- 0.10 to 0.60%,
- Mn:
- 0.2 to 2.0%,
- P:
- 0.035% or less,
- S:
- 0.010% or less,
- Cu:
- 2.50 to 4.50%,
- Ni:
- 9.00 to 16.00%,
- Cr:
- 15.00 to 20.00%,
- Mo:
- 0.20 to 1.50%,
- Nb:
- 0.15 to 0.60%,
- N:
- 0.05 to 0.15%,
- B:
- 0.0010 to 0.0060%,
- V:
- 0 to 0.50%,
- Ti:
- 0 to 0.500%,
- Co:
- 0 to 1.00%,
- W:
- 0 to 1.00%,
- Ta:
- 0 to 0.40%,
- Sn:
- 0 to 0.0300%,
- Ca:
- 0 to 0.0100%,
- Mg:
- 0 to 0.0100%, and
- REM:
- 0 to 0.0800%,
- with the balance:
- Fe and impurities, and
- satisfies Formulas (i) to (iii) shown below:
- 0.01
- ≤
- V
- ER
- +
- Ti
- ER
- +
- Nb
- ER
- (
- i
- )
- 27.
- ≤
- 1.13
- (
- Ni
-
- —
-
- Ni
- ER
- )
- +
- (
- Cr
-
- —
-
- Cr
- ER
- )
- +
- 1.85
- (
- Mo
-
- —
-
- Mo
- ER
- )
- +
- 1.79
- (
- Nb
-
- —
-
- Nb
- ER
- )
- <
- 40.5
- (
- ii
- )
- Nb
- ER
- <
- 0.052
- (
- iii
- )
- where symbols in the formulas are defined as follows, symbols of elements indicate contents (mass %) of the elements contained in the steel, and zero is assigned to a symbol of an element when the element is not contained:
- VER:
- Content of V in precipitates obtained by extraction residue analysis (mass %)
- TiER:
- Content of Ti in precipitates obtained by extraction residue analysis (mass %)
- NbER:
- Content of Nb in precipitates obtained by extraction residue analysis (mass %)
- NiER:
- Content of Ni in precipitates obtained by extraction residue analysis (mass %)
- CrER:
- Content of Cr in precipitates obtained by extraction residue analysis (mass %)
- MoER:
- Content of Mo in precipitates obtained by extraction residue analysis (mass %).
Dependencies are inferred from the claim text.