US2024247331A1PendingUtilityA1
Austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen, and manufacturing method therefor
Est. expiryJan 20, 2043(~16.5 yrs left)· nominal 20-yr term from priority
C21D 8/00C21D 2211/001B22D 7/00C21D 9/70C21D 8/0226C22C 38/06C22C 38/52C22C 38/48C22C 38/46C22C 38/001C22C 38/44C22C 38/42C22C 38/58C21D 2211/008C21D 6/008C21D 6/005C21D 6/004C22C 38/002C22C 38/02C22C 38/04C22C 38/50C22C 38/54C22C 2202/04C21D 1/26C21D 7/02C21D 7/13C21D 8/005
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Claims
Abstract
The present invention relates to an austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen, having a composition consisting of: C≤0.20 mass %, 0.10 mass %≤ Si≤1.00 mass %, 0.10 mass %≤Mn≤2.0 mass %, P≤0.050 mass %, S≤0.050 mass %, 2.0 mass %≤Cu<4.0 mass %, 8.0 mass %≤ Ni≤11.5 mass %, 17.0 mass %<Cr≤22.0 mass %, Mo≤0.20 mass %, and N≤0.050 mass %, with the balance being Fe and inevitable impurities; having an Ni equivalent Nieq of 24.0 or more; and having a relative reduction in area of 0.8 or more.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . An austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen, having a composition consisting of:
C≤0.20 mass %,
0.10 mass %≤Si≤1.00 mass %,
0.10 mass %≤Mn≤2.0 mass %,
P≤0.050 mass %,
S≤0.050 mass %,
2.0 mass %≤ Cu<4.0 mass %,
8.0 mass %≤ Ni≤11.5 mass %,
17.0 mass %<Cr≤22.0 mass %,
Mo≤0.20 mass %,
N≤0.050 mass %, and
optionally at least one selected from the group consisting of:
V≤0.5 mass %,
Nb≤0.5 mass %,
Ca≤0.03 mass %,
B≤0.05 mass %,
Zr≤0.5 mass %,
W≤2.0 mass %,
Al≤0.05 mass %,
Mg≤0.01 mass %, and
Co≤1.0 mass %,
with the balance being Fe and inevitable impurities; having an Ni equivalent Nieq represented by the following formula (1) of 24.0 or more:
Nieq
=
[
%
Ni
]
+
15.9
[
%
C
]
+
0.32
[
%
Si
]
+
0
.66
[
%
Mn
]
+
0
.47
[
%
Cr
]
+
0
.64
[
%
Mo
]
+
[
%
Cu
]
+
15.9
[
%
N
]
(
1
)
here, [% Z] represents a content (mass %) of an element Z; and
having a relative reduction in area represented by the following formula (2) of 0.8 or more:
relative
reduction
in
area
=
A
/
B
(
2
)
here,
A is a reduction in area at rupture of a round bar tensile test piece when a slow strain rate test is performed under conditions of a test temperature of −60° C. and a test atmosphere of hydrogen gas at 87.5 MPa, and
B is a reduction in area at rupture of a round bar tensile test piece when a slow strain rate test is performed under conditions of a test temperature of −60° C. and a test atmosphere of helium gas at 87.5 MPa.
2 . The austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen according to claim 1 , having
a tensile strength measured at 25° C. of 500 MPa or more, and an amount of martensite in a metal structure of 1.0 vol % or less.
3 . The austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen according to claim 1 , further satisfying one or more selected from the group consisting of:
0 mass %<V≤0.5 mass %, 0 mass %<Nb≤0.5 mass %, 0 mass %<Ca≤0.03 mass %, 0 mass %<B≤0.05 mass %, 0 mass %<Zr≤0.5 mass %, 0 mass %<W≤2.0 mass %, 0 mass %<Al≤0.05 mass %, and 0 mass %<Mg≤0.01 mass %.
4 . The austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen according to claim 2 , further satisfying one or more selected from the group consisting of:
0 mass %<V≤0.5 mass %, 0 mass %<Nb≤0.5 mass %, 0 mass %<Ca≤0.03 mass %, 0 mass %<B≤0.05 mass %, 0 mass %<Zr≤0.5 mass %, 0 mass %<W≤2.0 mass %, 0 mass %<Al≤0.05 mass %, and 0 mass %<Mg≤0.01 mass %.
5 . The austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen according to claim 1 , further satisfying:
0 mass %<Co≤1.0 mass %.
6 . The austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen according to claim 2 , further satisfying:
0 mass %<Co≤1.0 mass %.
7 . The austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen according to claim 3 , further satisfying:
0 mass %<Co≤1.0 mass %.
8 . The austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen according to claim 4 , further satisfying:
0 mass %<Co≤1.0 mass %.
9 . A manufacturing method for an austenitic stainless steel for high-pressure hydrogen gas or liquid hydrogen, comprising:
a first step of melting and casting a raw material to obtain an ingot having a composition consisting of:
C≤0.20 mass %,
0.10 mass %≤ Si≤1.00 mass %,
0.10 mass %≤ Mn≤2.0 mass %,
P≤0.050 mass %,
S≤0.050 mass %,
2.0 mass %≤ Cu<4.0 mass %,
8.0 mass %≤ Ni≤11.5 mass %,
17.0 mass %<Cr≤22.0 mass %,
Mo≤0.20 mass %,
N≤0.050 mass %, and
optionally at least one selected from the group consisting of:
V≤0.5 mass %,
Nb≤0.5 mass %,
Ca≤0.03 mass %,
B≤0.05 mass %,
Zr≤0.5 mass %,
W≤2.0 mass %,
Al≤0.05 mass %,
Mg≤0.01 mass %, and
Co≤1.0 mass %,
with the balance being Fe and inevitable impurities, and having an Ni equivalent Nieq represented by the following formula (1) of 24.0 or more:
Nieq
=
[
%
Ni
]
+
15.9
[
%
C
]
+
0.32
[
%
Si
]
+
0
.66
[
%
Mn
]
+
0
.47
[
%
Cr
]
+
0
.64
[
%
Mo
]
+
[
%
Cu
]
+
15.9
[
%
N
]
(
1
)
here, [% Z] represents a content (mass %) of an element Z;
a second step of subjecting the ingot to a soaking treatment at a temperature of 1,200° ° C. or higher, and
a third step of performing a primary hot working on the material subjected to the socking treatment.Join the waitlist — get patent alerts
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