Austenitic stainless steel material

Patent metadata

Field	Value
Publication number	US-12435402-B2
Application number	US-202117787972-A
Country	US
Kind code	B2
Filing date	Jan 8, 2021
Priority date	Jan 9, 2020
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

An austenitic stainless steel material that has a passivation film on a surface is provided. The austenitic stainless steel material has a chemical composition consisting of, in mass %, C: 0.10% or less, Si: 1.0% or less, Mn: 8.0-10.0%, P: 0.030% or less, S: 0.003% or less, Cr: 15.0-18.0%, Ni: 7.0-9.0%, N: 0.15-0.25%, Al: 0.005-0.20%, Ca: 0.0005-0.01%, Cu: less than 1.0%, Mo: less than 1.0%, B: 0-0.0050%, Nb: 0-0.50%, Ti: 0-0.50%, V: 0-0.50%, W: 0-0.50%, Zr: 0-0.50%, Co: 0-0.50%, Mg: 0-0.005%, Ga: 0-0.005%, Hf: 0-0.10%, REM: 0-0.10%, and the balance: Fe and impurities. An f value, namely, [Ni+0.72Cr+0.88Mo+1.11Mn−0.27Si+0.53Cu+12.93C+7.55N], is more than 29.5 and less than 32.5.

First claim

The invention claimed is:

1. An austenitic stainless steel material, which has a passivation film on a surface, comprising:
a chemical composition consisting of, in mass %,
C: 0.10% or less,
Si: 1.0% or less,
Mn: 8.0 to 10.0%,
P: 0.030% or less,
S: 0.0030% or less,
Cr: 15.0 to 18.0%,
Ni: 7.0 to 9.0%,
N: 0.15 to 0.25%,
Al: 0.005 to 0.20%,
Ca: 0.0005 to 0.01%,
Cu: less than 1.0%,
Mo: less than 1.0%,
B: 0 to 0.0050%,
Nb: 0 to 0.50%,
Ti: 0 to 0.50%,
V: 0 to 0.50%,
W: 0 to 0.50%,
Zr: 0 to 0.50%,
Co: 0 to 0.50%,
Mg: 0 to 0.005%,
Ga: 0 to 0.010%,
Hf: 0 to 0.10%,
REM: 0 to 0.10%, and
the balance: Fe and impurities,
wherein:
an f value calculated by Formula (i) below is more than 29.5 and less than 32.5;
cation fractions of a chemical composition in the passivation film satisfy Formula (ii) below:
f value=Ni+0.72Cr+0.88Mo+1.11Mn−0.27Si+0.53Cu+12.93C+7.55N  (i)

4.5≤(Mn+Fe)/Cr<9.0  (ii)

where, each symbol of an element in Formula (i) above represents a content (mass %) of the corresponding element contained in the steel, with a value of a symbol being taken as zero if the corresponding element is not contained, and each symbol of an element in Formula (ii) above represents a cation fraction (atomic percent) of the corresponding element contained in the passivation film, with a value of a symbol being taken as zero if the corresponding element is not contained.

2. The austenitic stainless steel material according to claim 1 , wherein:
the chemical composition contains one or more kinds of element selected from, in mass %,
B: 0.0002 to 0.0050%,
Nb: 0.01 to 0.50%,
Ti: 0.01 to 0.50%,
V: 0.01 to 0.50%,
W: 0.001 to 0.50%,
Zr: 0.01 to 0.50%,
Co: 0.01 to 0.50%,
Mg: 0.0001 to 0.005%,
Ga: 0.001 to 0.010%,
Hf: 0.01 to 0.10%, and
REM: 0.01 to 0.10%.

3. The austenitic stainless steel material according to claim 1 , wherein:
a shape of the steel material is a sheet.

4. The austenitic stainless steel material according to claim 1 , wherein:
the austenitic stainless steel material is used for hydrogen production equipment.

5. The austenitic stainless steel material according to claim 2 , wherein:
a shape of the steel material is a sheet.

6. The austenitic stainless steel material according to claim 2 , wherein:
the austenitic stainless steel material is used for hydrogen production equipment.

7. The austenitic stainless steel material according to claim 3 , wherein:
the austenitic stainless steel material is used for hydrogen production equipment.

8. The austenitic stainless steel material according to claim 5 , wherein:
the austenitic stainless steel material is used for hydrogen production equipment.

9. An austenitic stainless steel material, which has a passivation film on a surface, comprising:
a chemical composition comprising, in mass %,
C: 0.10% or less,
Si: 1.0% or less,
Mn: 8.0 to 10.0%,
P: 0.030% or less,
S: 0.0030% or less,
Cr: 15.0 to 18.0%,
Ni: 7.0 to 9.0%,
N: 0.15 to 0.25%,
Al: 0.005 to 0.20%,
Ca: 0.0005 to 0.01%,
Cu: less than 1.0%,
Mo: less than 1.0%,
B: 0 to 0.0050%,
Nb: 0 to 0.50%,
Ti: 0 to 0.50%,
V: 0 to 0.50%,
W: 0 to 0.50%,
Zr: 0 to 0.50%,
Co: 0 to 0.50%,
Mg: 0 to 0.005%,
Ga: 0 to 0.010%,
Hf: 0 to 0.10%,
REM: 0 to 0.10%, and
the balance: Fe and impurities,
wherein:
an f value calculated by Formula (i) below is more than 29.5 and less than 32.5;
cation fractions of a chemical composition in the passivation film satisfy Formula (ii) below:
f value=Ni+0.72Cr+0.88Mo+1.11Mn−0.27Si+0.53Cu+12.93C+7.55N  (i)

3.5≤(Mn+Fe)/Cr<9.0  (ii)

where, each symbol of an element in Formula (i) above represents a content (mass %) of the corresponding element contained in the steel, with a value of a symbol being taken as zero if the corresponding element is not contained, and each symbol of an element in Formula (ii) above represents a cation fraction (atomic percent) of the corresponding element contained in the passivation film, with a value of a symbol being taken as zero if the corresponding element is not contained.

Assignees

• Nippon Steel Stainless Steel Corp

Inventors

• Hatano Masaharu
• Matsumoto Kazuhisa
• Matsumoto Mitsuki

Classifications

• C21D8/02

  during manufacturing of plates or strips (C21D8/12 takes precedence) · CPC title

• C21D8/10

  during manufacturing of tubular bodies · CPC title

• C22C38/54

  with boron · CPC title

• C22C38/52

  with cobalt · CPC title

• C22C38/50

  with titanium or zirconium · CPC title