US 2025/0051894 A1Published application

Austenitic stainless steel and manufacturing method therefor

AssigneePosco

InventorsSeokweon Song, Minam Park

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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.

Claims11

Dependent claims

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.

122 more elements

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.

158 more elements

Dependencies are inferred from the claim text.

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Abstract