US2024279764A1PendingUtilityA1
Martensitic stainless steel for hydrogen gas environment and manufacturing method therefor
Est. expiryFeb 17, 2043(~16.6 yrs left)· nominal 20-yr term from priority
C21D 8/06C21D 8/00C21D 2211/001C21D 2211/008C21D 6/04C21D 6/008C21D 6/005C21D 6/004C21D 1/18C22C 38/54C22C 38/46C22C 38/44C22C 38/42C22C 38/001C22C 38/48C22C 38/60C22C 38/002C22C 38/04C22C 38/02C21D 9/0062C21D 1/22C21D 9/525C21D 8/065
67
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Claims
Abstract
Disclosed is a martensitic stainless steel for a hydrogen gas environment, having a composition consisting of: 0.02 mass %≤C≤0.30 mass %, Si≤1.50 mass %, Mn≤1.50 mass %, P≤0.150 mass %, S≤0.150 mass %, 8.0 mass %≤Cr≤22.0 mass %, 1.0 mass %≤Ni≤6.0 mass %, 0.01 mass %≤Nb≤1.0 mass %, and N≤0.12 mass %, and optionally at least one selected from the group consisting of: Cu≤6.00 mass %, Mo≤3.00 mass %, V≤1.50 mass %, and B≤0.0500 mass %, with the balance being Fe and inevitable impurities; having: a crystal grain size number of prior austenite grains of 2.0 or more, an amount of retained austenite of 40 vol % or less, a tensile strength of 1,500 MPa or less, and satisfying D H2(0.7) /D air ≥0.8.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A martensitic stainless steel for a hydrogen gas environment, having a composition consisting of:
0.02
mass
%
≤
C
≤
0.3
mass
%
,
Si
≤
1.5
mass
%
,
Mn
≤
1.5
mass
%
,
P
≤
0.15
mass
%
,
S
≤
0.15
mass
%
,
8.
mass
%
≤
Cr
≤
22.
mass
%
,
1.
mass
%
≤
Ni
≤
6.
mass
%
,
0.01
mass
%
≤
Nb
≤
1.
mass
%
,
and
N
≤
0.12
mass
%
,
and
optionally at least one selected from the group consisting of:
Cu
≤
6.
mass
%
,
Mo
≤
3.
mass
%
,
V
≤
1.5
mass
%
,
and
B
≤
0.05
mass
%
,
with the balance being Fe and inevitable impurities;
having:
a crystal grain size number of prior austenite grains of 2.0 or more,
an amount of retained austenite of 40 vol % or less,
a tensile strength of 1,500 MPa or less, and
satisfying the following formula (1):
D
H
2
(
0.7
)
/
D
a
i
r
≥
0
.
8
(
1
)
here, D air represents a displacement at a time point when stress shows a local maximum in a stress-displacement curve obtained by performing a tensile test under a condition of a strain rate of 5×10 −5 /s in the atmosphere at normal temperature (25° C.), and
D H2(0.7) represents a displacement at a time point when stress shows a local maximum or a maximum value in a stress-displacement curve obtained by performing a tensile test under a condition of a strain rate of 5×10 −5 /s in hydrogen gas of 0.7 MPa at normal temperature (25° C.).
2 . The martensitic stainless steel for a hydrogen gas environment according to claim 1 , wherein the composition further satisfies:
0.01
mass
%
≤
Cu
≤
6.
mass
%
.
3 . The martensitic stainless steel for a hydrogen gas environment according to claim 1 , wherein the composition further satisfies at least one selected from the group consisting of:
0.01
mass
%
≤
Mo
≤
3.
mass
%
,
0.01
mass
%
≤
V
≤
1.5
mass
%
,
and
0.0001
mass
%
≤
B
≤
0.05
mass
%
.
4 . A manufacturing method for a martensitic stainless steel for a hydrogen gas environment, comprising:
a first step of manufacturing a material consisting of:
0.02
mass
%
≤
C
≤
0.3
mass
%
,
Si
≤
1.5
mass
%
,
Mn
≤
1.5
mass
%
,
P
≤
0.15
mass
%
,
S
≤
0.15
mass
%
,
8.
mass
%
≤
Cr
≤
22.
mass
%
,
1.
mass
%
≤
Ni
≤
6.
mass
%
,
0.01
mass
%
≤
Nb
≤
1.
mass
%
,
and
N
≤
0.12
mass
%
,
and
optionally at least one selected from the group consisting of:
Cu
≤
6.
mass
%
,
Mo
≤
3.
mass
%
,
V
≤
1.5
mass
%
,
and
B
≤
0.05
mass
%
,
with the balance being Fe and inevitable impurities;
a second step of subjecting the material to a quenching from a temperature equal to or higher than an A c3 point and lower than a solidus temperature, or further performing a sub-zero treatment on the material after the quenching, and
a third step of subjecting the material after the quenching or after the sub-zero treatment to a tempering one or more times under conditions of a final tempering temperature of 200° C. or higher and 800° C. or lower and a final tempering time of 10 minutes or more and 24 hours or less to obtain the martensitic stainless steel for a hydrogen gas environment according to claim 1 .Join the waitlist — get patent alerts
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