US2025333812A1PendingUtilityA1
Austenite stainless steel and manufacturing method therefor
Est. expiryMay 31, 2042(~15.8 yrs left)· nominal 20-yr term from priority
C21D 8/02C22C 38/42C22C 38/58C22C 38/04C22C 38/02C21D 8/0263C21D 8/0236C21D 8/0226C21D 6/008C21D 6/005C21D 6/004C21D 2211/001C21D 8/0273C22C 38/001C21D 9/46C21D 8/0205
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Claims
Abstract
Provided are an austenite stainless steel having high strength, high ductility, and improved corrosion resistance by realizing ultrafine grain characteristics and a manufacturing method therefor. The austenite stainless steel according to an embodiment of the present disclosure includes, in weight %, at least 0.05% but not more than 0.1% of C, at least 0.2% but not more than 0.7% of Si, at least 2.0% but not more than 4.0% of Mn, more than 0% but less than 0.1% of P, more than 0% but less than 0.01% of S, at least 17% but not more than 19% of Cr, at least 2.0% but not more than 4.0% of Ni, at least 1.0% but not more than 2.5% of Cu, at least 0.15% but not more than 0.25% of N, and the balance being iron (Fe) and inevitable impurities and is 5 μm or less in average grain diameter of the thickness center.
Claims
exact text as granted — not AI-modified1 . An austenite stainless steel comprising, in weight %, at least 0.05% but not more than 0.1% of C, at least 0.2% but not more than 0.7% of Si, at least 2.0% but not more than 4.0% of Mn, more than 0% but less than 0.1% of P, more than 0% but less than 0.01% of S, at least 17% but not more than 19% of Cr, at least 2.0% but not more than 4.0% of Ni, at least 1.0% but not more than 2.5% of Cu, at least 0.15% but not more than 0.25% of N, and the balance being iron (Fe) and inevitable impurities,
wherein an average grain diameter of the thickness center is 5 μm or less.
2 . The austenite stainless steel according to claim 1 , wherein an austenite stability parameter (ASP) represented by Expression (1) below is −30 to 30:
551
-
462
×
(
[
C
]
+
[
N
]
)
-
9.2
×
[
Si
]
-
8.1
×
[
Mn
]
-
13.
7
×
[
Cr
]
-
29
×
(
[
Ni
]
+
[
Cu
]
)
Expression
(
1
)
(in Expression (1), [C], [N], [Si], [Mn], [Cr], [Ni], and [Cu] represent weight percentages (wt %) of respective elements).
3 . The austenite stainless steel according to claim 1 , wherein a strength stability parameter (SSP) represented by Expression (2) below is 0 or more:
5
8
+
1
3
2
×
[
C
]
-
7
.
9
×
[
Si
]
+
1.
×
[
Mn
]
-
5
.
6
×
[
Cr
]
+
7.
×
[
Ni
]
+
3.9
×
[
Cu
]
+
1.7
×
[
N
]
Expression
(
2
)
(in Expression (2), [C], [Si], [Mn], [Cr], [Ni], [Cu], and [N] represent weight percentages (wt %) of respective elements).
4 . The austenite stainless steel according to claim 1 , wherein a pitting resistance equivalent number (PREN) represented by Expression (3) below is 17 or more:
[
Cr
]
-
0
.
5
×
[
Mn
]
+
1
6
×
[
N
]
Expression
(
3
)
(in Expression (3), [Cr], [Mn], and [N] represent weight percentages (wt %) of respective elements).
5 . The austenite stainless steel according to claim 1 , wherein a yield strength is 600 MPa or more.
6 . The austenite stainless steel according to claim 1 , wherein an elongation is 30% or more.
7 . The austenite stainless steel according to claim 1 , wherein a pitting potential value is 200 mV or more.
8 . The austenite stainless steel according to claim 1 , wherein a thickness is 0.4 mm to 2.0 mm.
9 . A method for manufacturing an austenite stainless steel, the method comprising:
manufacturing an ingot including, in weight %, at least 0.05% but not more than 0.1% of C, at least 0.2% but not more than 0.7% of Si, at least 2.0% but not more than 4.0% of Mn, more than 0% but less than 0.1% of P, more than 0% but less than 0.01% of S, at least 17% but not more than 19% of Cr, at least 2.0% but not more than 4.0% of Ni, at least 1.0% but not more than 2.5% of Cu, at least 0.15% but not more than 0.25% of N, and the balance being iron (Fe) and inevitable impurities; hot rolling the ingot into a hot-rolled steel sheet; cold rolling the hot-rolled steel sheet into a cold-rolled steel sheet; and final annealing the cold-rolled steel sheet.
10 . The method according to claim 9 , wherein the ingot has an austenite stability parameter (ASP), represented by Expression (1) below, of −30 to 30:
551
-
462
×
(
[
C
]
+
[
N
]
)
-
9.2
×
[
Si
]
-
8.1
×
[
Mn
]
-
13.
7
×
[
Cr
]
-
29
×
(
[
Ni
]
+
[
Cu
]
)
Expression
(
1
)
(in Expression (1), [C], [N], [Si], [Mn], [Cr], [Ni], and [Cu] represent weight percentages (wt %) of respective elements).
11 . The method according to claim 9 , wherein the ingot has a strength stability parameter (SSP), represented by Expression (2) below, of 0 or more:
5
8
+
1
3
2
×
[
C
]
-
7
.
9
×
[
Si
]
+
1.
×
[
Mn
]
-
5
.
6
×
[
Cr
]
+
7.
×
[
Ni
]
+
3.9
×
[
Cu
]
+
1.7
×
[
N
]
Expression
(
2
)
(in Expression (2), [C], [Si], [Mn], [Cr], [Ni], [Cu], and [N] represent weight percentages (wt %) of respective elements).
12 . The method according to claim 9 , wherein the ingot has a pitting resistance equivalent number (PREN), represented by Expression (3) below, of 17 or more:
[
Cr
]
-
0
.
5
×
[
Mn
]
+
1
6
×
[
N
]
Expression
(
3
)
(in Expression (3), [Cr], [Mn], and [N] represent weight percentages (wt %) of respective elements).
13 . The method according to claim 9 , further comprising intermediate annealing the hot-rolled steel sheet before the cold rolling.
14 . The method according to claim 13 , wherein the intermediate annealing is performed at a temperature of 1050° C. to 1150° C.
15 . The method according to claim 9 , wherein the final annealing is performed at a temperature of 800° C. to 850° C.
16 . The method according to claim 9 , wherein the cold rolling is performed to adjust a thickness reduction ratio of the hot rolled steel sheet to 50% or more.Join the waitlist — get patent alerts
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