US 2022/0090249 A1Published application

Free-cutting copper alloy and method for manufacturing free-cutting copper alloy

AssigneeMitsubishi Materials Corporation

InventorsKeiichiro Oishi, Kouichi Suzaki, Hiroki Goto

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Abstract

This free-cutting copper alloy includes Cu: more than 61.0% and less than 65.0%, Si: more than 1.0% and less than 1.5%, Pb: 0.003% to less than 0.20%, and P: more than 0.003% and less than 0.19%, with the remainder being Zn and unavoidable impurities, a total content of Fe, Mn, Co, and Cr is less than 0.40%, a total content of Sn and Al is less than 0.40%, a relationship of 56.5≤f1=[Cu]−4.5×[Si]+0.5×[Pb]−[P]≤59.5 is satisfied, constituent phases of a metallographic structure have relationships of 20≤(α)≤80, 15≤(β)≤80, 0≤(γ)<8, 18×(γ)/(β)<9, 20≤(γ)1/2×3+(β)×([Si])1/2≤88, and 33≤(γ)1/2×3+(β)×([Si])1/2+([Pb])1/2×35+([P])1/2×15, and a compound including P is present in β phase.

Claims9

Dependent claims

A free-cutting copper alloy comprising:

higher than 61.0 mass % and lower than 65.0 mass % of Cu;
higher than 1.0 mass % and lower than 1.5 mass % of Si;
higher than or equal to 0.003 mass % and lower than 0.20 mass % of Pb;
and
higher than 0.003 mass % and lower than 0.19 mass % of P,
with the balance being Zn and inevitable impurities,
wherein among the inevitable impurities, a total content of Fe, Mn, Co, and Cr is lower than 0.40 mass % and a total content of Sn and Al is lower than 0.40 mass %,
when a Cu content is represented by [Cu] mass %, a Si content is represented by [Si] mass %, a Pb content is represented by [Pb] mass %, and a P content is represented by [P] mass %, a relationship of
56.5
≤
f
⁢
⁢
1
=
[
Cu
]
-
4.5
×
[
Si
]
+
0.5
×
[
Pb
]
-
[
P
]
≤
59.5
is satisfied,
in constituent phases of a metallographic structure excluding non-metallic inclusions, among 10 metallic phases consisting of α phase, β phase, γ phase, δ phase, ε phase, ζ phase, η phase, κ phase, μ phase, and χ phase, when an area ratio of α phase is represented by (α)%, an area ratio of γ phase is represented by (γ)%, an area ratio of β phase is represented by (β)%, an area ratio of μ phase is represented by (μ)%, an area ratio of κ phase is represented by (κ)%, an area ratio of δ phase is represented by (δ)%, an area ratio of ε phase is represented by (ε)%, an area ratio of ζ phase is represented by (ζ)%, an area ratio of η phase is represented by (η)%, and an area ratio of χ phase is represented by (χ)%, providing that (α)+(β)+(γ)+(μ)+(κ)+(δ)+(ε)+(ζ)+(η)+(χ)=100, relationships of
2
⁢
0
≤
(
α
)
≤
8
⁢
0
,
⁢
1
⁢
5
≤
(
β
)
≤
8
⁢
0
,
⁢
0
≤
(
γ
)
<
8
,
⁢
1
⁢
8
×
(
γ
)
⁢
/
⁢
(
β
)
<
9
,
⁢
2
⁢
0
≤
(
γ
)
1
/
2
×
3
+
(
β
)
×
(
[
Si
]
)
1
/
2
≤
88
,
and
⁢
33
≤
(
γ
)
1
/
2
×
3
+
(
β
)
×
(
[
Si
]
)
1
/
2
+
(
[
Pb
]
)
1
/
2
×
3
⁢
5
+
(
[
P
]
)
1
/
2
×
1
⁢
5
are satisfied, and
a P-containing compound having a grain size of 3 μm or less in diameter which can be observed at least in an examination using an electron microscope at a magnification of 2000 times is present in the β phase.

168 more elements

A free-cutting copper alloy comprising:

higher than or equal to 61.7 mass % and lower than or equal to 64.3 mass % of Cu;
higher than or equal to 1.02 mass % and lower than or equal to 1.35 mass % of Si;
higher than or equal to 0.005 mass % and lower than or equal to 0.10 mass % of Pb;
and
higher than or equal to 0.02 mass % and lower than or equal to 0.14 mass % of P,
with the balance being Zn and inevitable impurities,
wherein among the inevitable impurities, a total content of Fe, Mn, Co, and Cr is lower than or equal to 0.30 mass % and a total content of Sn and Al is lower than or equal to 0.30 mass %,
when a Cu content is represented by [Cu] mass %, a Si content is represented by [Si] mass %, a Pb content is represented by [Pb] mass %, and a P content is represented by [P] mass %, a relationship of
57.0
≤
f
⁢
⁢
1
=
[
Cu
]
-
4.5
×
[
Si
]
+
0.5
×
[
Pb
]
-
[
P
]
≤
5
⁢
9.0
is satisfied,
in constituent phases of a metallographic structure excluding non-metallic inclusions, among 10 metallic phases consisting of α phase, β phase, γ phase, δ phase, ε phase, ζ phase, η phase, κ phase, μ phase, and χ phase, when an area ratio of α phase is represented by (α)%, an area ratio of γ phase is represented by (γ)%, an area ratio of β phase is represented by (β)%, an area ratio of μ phase is represented by (μ)%, an area ratio of κ phase is represented by (κ)%, an area ratio of δ phase is represented by (δ)%, an area ratio of ε phase is represented by (ε)%, an area ratio of ζ phase is represented by (ζ)%, an area ratio of η phase is represented by (η)%, and an area ratio of χ phase is represented by (χ)%, providing that (α)+(β)+(γ)+(μ)+(κ)+(δ)+(ε)+(ζ)+(η)+(χ)=100, relationships of
3
⁢
0
≤
(
α
)
≤
7
⁢
5
,
⁢
2
⁢
5
≤
(
β
)
≤
7
⁢
0
,
⁢
0
≤
(
γ
)
<
4
,
⁢
1
⁢
8
×
(
γ
)
⁢
/
⁢
(
β
)
<
2
,
⁢
3
⁢
0
≤
(
γ
)
1
/
2
×
3
+
(
β
)
×
(
[
Si
]
)
1
/
2
≤
77
,
and
44
≤
(
γ
)
1
/
2
×
3
+
(
β
)
×
(
[
Si
]
)
1
/
2
+
(
[
Pb
]
)
1
/
2
×
3
⁢
5
+
(
[
P
]
)
1
/
2
×
1
⁢
5
are satisfied, and
a P-containing compound having a grain size of 3 μm or less in diameter which can be observed at least in an examination using an electron microscope at a magnification of 2000 times is present in the β phase.

169 more elements

Dependencies are inferred from the claim text.