Low thermal expansion alloy

Patent metadata

Field	Value
Publication number	US-2026049385-A1
Application number	US-202519268621-A
Country	US
Kind code	A1
Filing date	Jul 14, 2025
Priority date	Aug 14, 2024
Publication date	Feb 19, 2026
Grant date	—

Abstract

The present invention relates to a low thermal expansion alloy, consisting of: 0.10 to 0.40 mass % of C; up to 1.00 mass % of Si; 0.10 to 2.00 mass % of Mn; up to 0.050 mass % of P; up to 0.015 mass % of S; 0.10 to 4.00 mass % of Cu; 35.0 to 45.0 mass % of Ni; 0.10 to 1.00 mass % of V; up to 4.00 mass % of Mo; each up to 0.50 mass % of Cr, Co, Al, Ti, Nb, W, Zr, Hf, and Ta; and each up to 0.050 mass % of B, Mg, Ca, and REM, with the balance being Fe and unavoidable impurities. The low thermal expansion alloy satisfies A≥38.0 and 40.6<B≤44.5. Here, A and B are defined in the description.

First claim

What is claimed is:

1 . A low thermal expansion alloy consisting of:
0.10 mass %≤C≤0.40 mass %; Si≤1.00 mass %; 0.10 mass %≤Mn≤2.00 mass %; P≤0.050 mass %; S≤0.015 mass %; 0.10 mass %≤Cu≤4.00 mass %; 35.0 mass %≤Ni≤45.0 mass %; 0.10 mass %≤V≤1.00 mass %; 0 mass %≤Cr≤0.50 mass %; 0 mass %≤Mo≤4.00 mass %; 0 mass %≤Co≤0.50 mass %; 0 mass %≤Al≤0.50 mass %; 0 mass %≤Ti≤0.50 mass %; 0 mass %≤Nb≤0.50 mass %; 0 mass %≤W≤0.50 mass %; 0 mass %≤Zr≤0.50 mass %; 0 mass %≤Hf≤0.50 mass %; 0 mass %≤Ta≤0.50 mass %; 0 mass %≤B≤0.050 mass %; 0 mass %≤Mg≤0.050 mass %; 0 mass %≤Ca≤0.050 mass %; and 0 mass %≤REM≤0.050 mass %, with the balance being Fe and unavoidable impurities, wherein the low thermal expansion alloy satisfies the following formulas (1) and (2):

A
≥
38.

,
and

(
1
)

40.6
<
B
≤

4
4.5

,

(
2
)

wherein

A
=

[
Ni
]

+

[
Co
]

+

0.7
*

[
Cu
]

-

[
Si
]

-

[
Mn
]

-

[
Cr
]

-

0.5
*

[
Mo
]

-

0.5
*

[
V
]

,

and

B
=

[
Ni
]

+

0.8
*

[
Co
]

+

[
Cu
]

+

6
*

[
C
]

+

1.1
*

[
Si
]

+

[
Mn
]

+

1.2
*

[
Cr
]

+

0.2
*

[
Mo
]

-

0.5
*

[
V
]

.

2 . The low thermal expansion alloy according to claim 1 , having a tensile strength of 500 MPa or more,
wherein the “tensile strength” refers to a value obtained by performing a tensile test at room temperature (25° C.) in an atmosphere using a round bar-shaped No. 3 test piece having a parallel portion with a diameter of 6 mm in accordance with ASTM A370-17.

3 . The low thermal expansion alloy according to claim 1 , having a thermal expansion coefficient of 3.5×10 −6 /° C. or more and 6.0×10 −6 /° C. or less,
wherein the “thermal expansion coefficient” refers to an average linear thermal expansion coefficient from 30° C. to 100° C., measured in accordance with ASTM E228-17.

4 . The low thermal expansion alloy according to claim 1 , having a magnetic transformation point of 280° C. or higher.

5 . The low thermal expansion alloy according to claim 1 , wherein the unavoidable impurities include at least one selected from the group consisting of:
Sn≤0.010 mass %; Zn≤0.010 mass %; As≤0.010 mass %; Se≤0.010 mass %; Sb≤0.010 mass %; Ag≤0.010 mass %; Bi≤0.0010 mass %; O≤0.050 mass %, and N≤0.050 mass %.

Assignees

• Daido Steel Co Ltd

Inventors

• Kudo Daisuke
• Hattori Hiroki
• Furusho Chihiro
• Koyanagi Yoshihiko

Classifications

• C22C38/52

  with cobalt · CPC title

• C22C38/50

  with titanium or zirconium · CPC title

• C22C38/48

  with niobium or tantalum · CPC title

• C22C38/46

  with vanadium · CPC title

• C22C38/44

  with molybdenum or tungsten · CPC title