US2025051894A1PendingUtilityA1
Austenitic stainless steel and manufacturing method therefor
Est. expiryDec 16, 2041(~15.4 yrs left)· nominal 20-yr term from priority
C21D 8/02C22C 38/04C21D 6/005C21D 6/004C22C 38/42C22C 38/02C22C 38/004C22C 38/001C21D 2211/001C21D 8/0273C21D 8/0263C21D 8/0236C21D 8/0226C21D 9/46C22C 38/58
49
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Claims
Abstract
The present disclosure relates to an austenitic stainless steel and a manufacturing method therefor, and specifically, to an austenitic stainless steel and a manufacturing method therefor, wherein the austenitic stainless steel can secure both excellent strength and ductility even after undergoing low-temperature annealing and have excellent competitiveness and corrosion resistance.
Claims
exact text as granted — not AI-modified1 . An austenitic stainless steel comprising, in percent by weight (wt %), 0.005 to 0.060% of carbon (C), 0.1 to 1.5% of silicon (Si), 5.0 to 10.0% of manganese (Mn), more than 0% but not more than 3% of nickel (Ni), 14.0 to 18.0% of chromium (Cr), more than 0% but not more than 2.0% of copper (Cu), 0.01 to 0.25% of nitrogen (N), and the balance of iron (Fe) and inevitable impurities,
wherein an α value defined by Equation (1) below satisfies 10,000 or more, a β value defined by Equation (2) below satisfies 100 or more,
α
=
Y
S
×
E
L
-
200
(
8
[
N
i
]
+
[
C
r
]
+
3
[
M
n
]
)
Equation
(
1
)
β
=
A
S
P
+
[
150
/
d
]
Equation
(
2
)
in Equation (1) and Equation (2),
[Ni], [Cr], and [Mn] represent amounts (wt %) of respective elements,
YS refers to yield stress (MPa),
EL refers to elongation (%),
austenitic stability parameter (ASP) is a value calculated by using Equation (2-1) below,
d is an average grain size (μm) of a thickness central region; and
ASP
=
551
-
462
(
[
C
]
+
[
N
]
)
-
9.2
[
S
i
]
-
8.1
[
M
n
]
-
13.7
[
C
r
]
-
29
(
[
N
i
]
+
[
C
u
]
)
Equation
(
2
-
1
)
in Equation (2-1), [C], [N], [Si], [Mn], [Cr], [Ni], and [Cu] represent amounts (wt %) of respective elements.
2 . The austenitic stainless steel according to claim 1 , wherein the average grain size (d) of the thickness central region is 5.0 μm or less.
3 . The austenitic stainless steel according to claim 1 , wherein the ASP value of Equation (2) satisfies a range of 15 to 70.
4 . The austenitic stainless steel according to claim 1 , wherein the austenitic stainless steel has a pitting potential value of 100 mV or more.
5 . The austenitic stainless steel according to claim 1 , wherein the austenitic stainless steel has a yield strength of 540.0 MPa or more and an elongation of 30.0% or more.
6 . A method for manufacturing an austenitic stainless steel, the method comprising:
providing a material comprising, in percent by weight (wt %), 0.005 to 0.060% of carbon (C), 0.1 to 1.5% of silicon (Si), 5.0 to 10.0% of manganese (Mn), more than 0% but not more than 3.0% of nickel (Ni), 14.0 to 18.0% of chromium (Cr), more than 0% but not more than 2.0% of copper (Cu), 0.01 to 0.25% of nitrogen (N), and the balance of iron (Fe) and inevitable impurities; hot rolling the material to obtain a hot-rolled steel sheet; cold rolling the hot-rolled steel sheet to prepare a cold-rolled steel sheet; and finally annealing the cold-rolled steel sheet, wherein the finally annealed steel sheet has an α value defined by Equation (1) below satisfying 10,000 or more, a β value defined by Equation (2) below satisfying 100 or more, and a γ defined by Equation (3) below satisfying 0 or more,
α
=
Y
S
×
E
L
-
200
(
8
[
N
i
]
+
[
C
r
]
+
3
[
M
n
]
)
Equation
(
1
)
β
=
A
S
P
+
[
150
/
d
]
Equation
(
2
)
γ
=
[
C
r
]
+
16
[
N
]
-
0.5
[
M
n
]
-
[
390
/
Temp
]
Equation
(
3
)
in Equation (1) to Equation (3),
[Ni], [Cr], [Mn], and [N] represent amounts (wt %) of respective elements,
YS refers to yield stress (MPa),
EL refers to elongation (%),
austenitic stability parameter (ASP) is a value calculated by using Equation (2-1) below,
d is an average grain size (μm) of a thickness central region,
Temp refers to a final annealing temperature (° C.); and
ASP
=
551
-
462
(
[
C
]
+
[
N
]
)
-
9.2
[
S
i
]
-
8.1
[
M
n
]
-
13.7
[
C
r
]
-
29
(
[
N
i
]
+
[
C
u
]
)
Equation
(
2
-
1
)
in Equation (2-1), [C], [N], [Si], [Mn], [Cr], [Ni], and [Cu] represent amounts (wt %) of respective elements.
7 . The method according to claim 6 , wherein the finally annealing is performed in a temperature range of 750 to 850° C.
8 . The method according to claim 6 , further comprising primarily annealing the hot-rolled steel sheet at 1000 to 1150° C. before the cold rolling.
9 . The method according to claim 6 , wherein the cold-rolled steel sheet is prepared by rolling the hot-rolled steel sheet with a thickness reduction ratio of 50% in a room temperature range.
10 . The method according to claim 6 , wherein the ASP value of the austenitic stainless steel satisfies a range of 15 to 70.
11 . The method according to claim 6 , wherein the finally annealed steel sheet has an average grain size (d) of the thickness central region of 5.0 μm or less.Join the waitlist — get patent alerts
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