Austenitic stainless steel with excellent productivity and cost reduction effect and method for producing same

Patent metadata

Field	Value
Publication number	US-12590359-B2
Application number	US-202117924230-A
Country	US
Kind code	B2
Filing date	Jun 22, 2021
Priority date	Jun 23, 2020
Publication date	Mar 31, 2026
Grant date	Mar 31, 2026

Abstract

Disclosed is a high-strength austenitic stainless steel and a method for producing same, wherein the austenitic stainless steel has high productivity due to excellent hot workability thereof and a superior cost reduction effect due to a large decrease in content of nickel (Ni) which is a high-priced element, and has a yield strength of 450 MPa or more and an elongation of 45% or more after cold rolling and annealing and an ultra-high strength of 1800 MPa or more even after skin pass rolling, and a method for producing same.

First claim

The invention claimed is:

1 . An austenitic stainless steel comprising, in percent by weight (wt %), 0.1 to 0.2% of C, 0.2 to 0.3% of N, 0.8 to 1.5% of Si, 7.0 to 8.5% of Mn, 15.0 to 17.0% of Cr, 0.5% or less (excluding 0) of Ni, 1.0% or less (excluding 0) of Cu, 0 to 0.2% of Nb, and the balance of Fe and inevitable impurities, and
satisfying Expression (1), (2), (3) and (4) below:
14≤23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn≤15.16  Expression (1):

30≤551−462(C+N)−9.2Si−8.1Mn−13.7Cr−29(Ni+Cu)−68Nb≤80  Expression (2):

16≤1+45C−5Si+0.09Mn+2.2Ni−0.28Cr−0.67Cu+88.6N≤20  Expression (3):

2
≤

(

(

Cr
+

1.5
Si

+

0.5
Nb

+
18

)

(

Ni
+

0.52
Cu

+

16
⁢

(

C
+
N

)

+

0.5
Mn

+
36

)

+
0.262

)

×
161

-
161

≤
10

Expression
⁢

(
4
)

wherein in Expression (1), (2), (3) and (4) C, N, Si, Mn, Cr, Ni, Cu and Nb represent contents (wt %) of the elements, respectively.

2 . The austenitic stainless steel according to claim 1 , wherein the austenitic stainless steel has a yield strength of 450 MPa or more after cold rolling and annealing and a yield strength of 1800 MPa or more after skin pass rolling.

3 . The austenitic stainless steel according to claim 1 , wherein the austenitic stainless steel has an elongation of 45% or more after cold rolling and annealing and an elongation of 3% or more after skin pass rolling.

4 . A method for producing the austenitic stainless steel according to claim 1 , the method comprising:
heating and hot rolling a slab comprising, in percent by weight (wt %), greater than 0.1 and 0.2% of C, 0.2 to 0.3% of N, 0.8 to 1.5% of Si, 7.0 to 8.5% of Mn, 15.0 to 17.0% of Cr, 0.5% or less (excluding 0) of Ni, 1.0% or less (excluding 0) of Cu, 0 to 0.2% of Nb, and the balance of Fe and inevitable impurities; hot annealing the hot-rolled steel sheet; cold rolling the hot-annealed steel sheet; and cold annealing the cold-rolled steel sheet, wherein the slab satisfies Expression (1), (2), (3) and (4) below:
14≤23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn=15.16  Expression (1):

30≤551−462(C+N)−9.2Si−8.1Mn−13.7Cr−29(Ni+Cu)−68Nb≤80  Expression (2):

16≤1+45C−5Si+0.09Mn+2.2Ni−0.28Cr−0.67Cu+88.6N≤20  Expression (3):

2
≤

(

(

Cr
+

1.5
Si

+

0.5
Nb

+
18

)

(

Ni
+

0.52
Cu

+

16
⁢

(

C
+
N

)

+

0.5
Mn

+
36

)

+
0.262

)

×
161

-
161

≤
10

Expression
⁢

Assignees

• Posco

Inventors

• Song Seokweon
• Paek Jong-Su
• Kim Hak

Classifications

• C21D8/02

  during manufacturing of plates or strips (C21D8/12 takes precedence) · CPC title

• C22C38/48

  with niobium or tantalum · CPC title

• C22C38/42

  with copper · CPC title

• C22C38/02

  containing silicon · CPC title

• C22C38/001

  containing N · CPC title