Austenitic stainless steel and hydrogen resistant member
Abstract
The present invention relates to an austenitic stainless steel, consisting of: C≤0.10 mass %, Si≤0.50 mass %, 3.0 mass %≤Mn≤8.0 mass %, P≤0.30 mass %, S≤0.30 mass %, 7.0 mass %≤Ni≤12.0 mass %, 18.0 mass %≤Cr ≤28.0 mass %, 1.0 mass %≤Mo≤3.0 mass %, 0.03 mass %≤V≤0.50 mass %, 0.0003 mass %≤B≤0.0300 mass %, 0.0001 mass %≤Ca≤0.0300 mass %, 0.35 mass %≤N≤0.80 mass %, and 0.001 mass %≤Co≤1.00 mass %, and optionally, W≤2.0 mass %, Zr≤0.20 mass %, and Ta≤0.50 mass %, with a balance being Fe and unavoidable impurities, and having a number density of coarse alloy carbonitrides of 3×10 5 pieces/mm 2 or less.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . An austenitic stainless steel, consisting of:
C
≤
0.1
mass
%
,
Si
≤
0.5
mass
%
,
3.
mass
%
≤
Mn
≤
8.
mass
%
,
P
≤
0.3
mass
%
,
S
≤
0.3
mass
%
,
7.
mass
%
≤
Ni
≤
12.
mass
%
,
18.
mass
%
≤
Cr
≤
28.
mass
%
,
1.
mass
%
≤
Mo
≤
3.
mass
%
,
0.03
mass
%
≤
V
≤
0.5
mass
%
,
0.0003
mass
%
≤
B
≤
0.03
mass
%
,
0.0001
mass
%
≤
Ca
≤
0.03
mass
%
,
0.35
mass
%
≤
N
≤
0.8
mass
%
,
and
0.001
mass
%
≤
Co
≤
1.
mass
%
,
and
optionally
,
W
≤
2.
mass
%
,
Zr
≤
0.2
mass
%
,
and
Ta
≤
0.5
mass
%
,
with a balance being Fe and unavoidable impurities, and
having a number density of coarse alloy carbonitrides of 3×10 5 pieces/mm 2 or less, where the “coarse alloy carbonitride” refers to an alloy carbonitride having an equivalent circle diameter of more than 1,000 nm.
2 . The austenitic stainless steel according to claim 1 , further satisfying at least one selected from the group consisting of:
0.3
mass
%
≤
W
≤
2.
mass
%
,
0.01
mass
%
≤
Zr
≤
0.2
mass
%
,
and
0.1
mass
%
<
Ta
≤
0.5
mass
%
.
3 . The austenitic stainless steel according to claim 1 , having a tensile strength measured at 25° C. being 690 MPa or more.
4 . The austenitic stainless steel according to claim 1 , having a crystal grain size number of an austenite crystal grain being less than 8.0.
5 . The austenitic stainless steel according to claim 1 , having a reduction of area measured at 25° C. being 30% or more.
6 . A hydrogen resistant member, comprising the austenitic stainless steel described in claim 1 .
7 . The hydrogen resistant member according to claim 6 , wherein the austenitic stainless steel comprises a portion that is in an as-solution treated state.
8 . The hydrogen resistant member according to claim 6 , comprising a butt-welded portion, wherein
the butt-welded portion has a tensile strength as welded, measured at 25° C., being 690 MPa or more.Join the waitlist — get patent alerts
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