U.S. patent application number 11/510854 was filed with the patent office on 2007-03-08 for copper alloy material and method of making same.
This patent application is currently assigned to HITACHI CABLE, LTD.. Invention is credited to Koichi Kotoku, Katsumi Nomura, Hiroaki Takano, Chingping Tong, Yoshiki Yamamoto.
Application Number | 20070051442 11/510854 |
Document ID | / |
Family ID | 37817643 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070051442 |
Kind Code |
A1 |
Yamamoto; Yoshiki ; et
al. |
March 8, 2007 |
Copper alloy material and method of making same
Abstract
A copper alloy material for electric parts having: 1.0 to 5.0
mass % of Ni; 0.2 to 1.0 mass % of Si; 0.05 to 2.0 mass % of Sn;
0.1 to 5.0 mass % of Zn; 0.01 to 0.3 mass % of P; 0.05 to 1.0 mass
% of at least one of Fe and Co; and the balance consisting of Cu
and an unavoidable impurity. The ratio, (Ni+Fe+Co)/(Si+P), between
the total mass of Ni, Fe and Co and the total mass of Si and P is 4
or more and 10 or less.
Inventors: |
Yamamoto; Yoshiki; (Tsukuba,
JP) ; Takano; Hiroaki; (Tsuchiura, JP) ;
Kotoku; Koichi; (Inashiki-gun, JP) ; Tong;
Chingping; (Tsuchiura, JP) ; Nomura; Katsumi;
(Tsuchiura, JP) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
HITACHI CABLE, LTD.
|
Family ID: |
37817643 |
Appl. No.: |
11/510854 |
Filed: |
August 28, 2006 |
Current U.S.
Class: |
148/684 ;
420/472 |
Current CPC
Class: |
C22C 9/06 20130101; C22F
1/08 20130101; C22C 9/04 20130101; C22C 9/02 20130101 |
Class at
Publication: |
148/684 ;
420/472 |
International
Class: |
C22C 9/02 20060101
C22C009/02; C22F 1/08 20060101 C22F001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 2, 2005 |
JP |
2005-255502 |
Claims
1. A copper alloy material for electric parts, comprising: 1.0 to
5.0 mass % of Ni; 0.2 to 1.0 mass % of Si; 0.05 to 2.0 mass % of
Sn; 0.1 to 5.0 mass % of Zn; 0.01 to 0.3 mass % of P; 0.05 to 1.0
mass % of at least one of Fe and Co; and the balance consisting of
Cu and an unavoidable impurity, wherein a ratio, (Ni+Fe+Co)/(Si+P),
between a total mass of Ni, Fe and Co and a total mass of Si and P
is 4 or more and 10 or less.
2. The copper alloy material according to claim 1, wherein: the
copper alloy material comprises a tensile strength of 700
N/mm.sup.2 or more.
3. The copper alloy material according to claim 1, wherein: the
copper alloy material comprises an elongation of 10% or more.
4. The copper alloy material according to claim 1, wherein: the
copper alloy material comprises an electric conductivity of 40%
IACS or more.
5. A copper alloy material for electric parts, comprising: 1.0 to
5.0 mass % of Ni; 0.2 to 1.0 mass % of Si; 0.05 to 2.0 mass % of
Sn; 0.1 to 5.0 mass % of Zn; 0.01 to 0.3 mass % of P; 0.05 to 1.0
mass % of at least one of Fe and Co; 0.01 to 1.0 mass % of at least
one of Mg, Ti, Cr and Zr and the balance consisting of Cu and an
unavoidable impurity, wherein a ratio, (Ni+Fe+Co)/(Si+P), between a
total mass of Ni, Fe and Co and a total mass of Si and P is 4 or
more and 10 or less.
6. The copper alloy material according to claim 5, wherein: the
copper alloy material comprises a tensile strength of 700
N/mm.sup.2 or more.
7. The copper alloy material according to claim 5, wherein: the
copper alloy material comprises an elongation of 10% or more.
8. The copper alloy material according to claim 5, wherein: the
copper alloy material comprises an electric conductivity of 40%
IACS or more.
9. A method of making the copper alloy material for electric parts
as defined in claim 1, comprising: preparing a copper alloy raw
material with the same composition and the same mass ratio as
defined in claim 1; a first cold rolling step that the copper alloy
raw material is cold-rolled down to a thickness of 1.1 to 1.3 times
a target thickness of a final product; a first heat treatment step
that the cold-rolled material in the first cold rolling step is
heated up to 700 to 850.degree. C. and then cooled to 300.degree.
C. or less at a cooling rate of 25.degree. C./min or more; a second
cold rolling step that the treated material in the first heat
treatment step is cold-rolled down to the target thickness; and a
second heat treatment step that the cold-rolled material in the
second cold rolling step is heated up to 400 to 500.degree. C. and
held for 30 min. to 3 hrs.
10. A method of making the copper alloy material for electric parts
as defined in claim 5, comprising: preparing a copper alloy raw
material with the same composition and the same mass ratio as
defined in claim 5; a first cold rolling step that the copper alloy
raw material is cold-rolled down to a thickness of 1.1 to 1.3 times
a target thickness of a final product; a first heat treatment step
that the cold-rolled material in the first cold rolling step is
heated up to 700 to 850.degree. C. and then cooled to 300.degree.
C. or less at a cooling rate of 25.degree. C./min or more; a second
cold rolling step that the treated material in the first heat
treatment step is cold-rolled down to the target thickness; and a
second heat treatment step that the cold-rolled material in the
second cold rolling step is heated up to 400 to 500.degree. C. and
held for 30 min. to 3 hrs.
Description
[0001] The present application is based on Japanese patent
application No. 2005-255502, the entire contents of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a copper alloy material for
electric parts such as a terminal, connector and lead frame and, in
particular, to a copper alloy material that is excellent in
mechanical strength such as tensile strength and yield strength, in
elongation, in electric conductivity and in bending workability.
This invention also relates to a method of making the copper alloy
material.
[0004] 2. Description of the Related Art
[0005] In recent years, an electronic hardware such as a cellular
phone or notebook PC is downsized, low-profiled and reduced in
weight. Along with this, electric and/or electronic components used
therein tend to be reduced in weight, length and thickness.
[0006] In the downsizing, although materials used therein also have
to be reduced in thickness, a material is needed to have a high
mechanical strength, a high spring property, and a good bending
workability even when it has the reduced thickness so as to keep a
reliability in electric connection.
[0007] Further, generated Joule heat increases with increasing in
applied current and in the number of electrodes due to the
sophistication of equipment. Thus, the material is strongly desired
to have a good electric conductivity than before. Such high
electric conductivity is needed especially in a terminal and
connector material for automobiles and a lead frame material for
power IC, where the applied current tends to increase rapidly.
[0008] Conventionally, phosphor bronze is used as a material for a
terminal, connector etc. However, there is a problem that the
phosphor bronze cannot satisfy sufficiently the updated
characteristics required to the connector material. For example,
since the phosphor bronze has a low electric conductivity of about
20% IACS, it cannot be suited to an increase in applied current
(i.e., it results in an increase of the generated Joule heat).
Further the phosphor bronze does not have an excellent
characteristic in migration resistance. Meanwhile, the migration is
a phenomenon that, when a condensation of moisture occurs between
electrodes, the Cu atom in the positive electrode is dissolved
(ionized) and precipitated on the negative electrode, so that the
short circuit between the electrodes can be caused. The phenomenon
is a serious problem especially on the connector or lead frame that
can be used in environment of high temperature and high humidity as
in automobiles. Further, it should be considered for the connector
or lead frame with an interelectrode pitch narrowed due to the
downsizing.
[0009] In order to solve the above problems, copper alloys
containing Cu--Ni--Si as a main component are suggested (e.g.,
JP-B-2572042, 2977845 and 3465541).
[0010] However, in the Cu--Ni--Si alloys, if it is intended to have
a high mechanical strength and a good spring property, the bending
workability is easy to deteriorate such that anisotropy in the
bending process becomes significant depending on the rolling
direction of the alloy strip.
SUMMARY OF THE INVENTION
[0011] It is an object of the invention to provide a copper alloy
material for electric parts, such as a terminal, connector and lead
frame, that is excellent in mechanical strength such as tensile
strength and yield strength, in elongation, in electric
conductivity and in bending workability to show reduced anisotropy
in the bending process. [0012] (1) According to one aspect of the
invention, a copper alloy material for electric parts
comprises:
[0013] 1.0 to 5.0 mass % of Ni;
[0014] 0.2 to 1.0 mass % of Si;
[0015] 0.05 to 2.0 mass % of Sn;
[0016] 0.1 to 5.0 mass % of Zn;
[0017] 0.01 to 0.3 mass % of P;
[0018] 0.05 to 1.0 mass % of at least one of Fe and Co; and
[0019] the balance consisting of Cu and an unavoidable
impurity,
[0020] wherein a ratio, (Ni+Fe+Co)/(Si+P), between a total mass of
Ni, Fe and Co and a total mass of Si and P is 4 or more and 10 or
less.
[0021] In the above invention, the following modifications can be
made. [0022] (i) The copper alloy material comprises a tensile
strength of 700 N/mm.sup.2 or more. [0023] (ii) The copper alloy
material comprises an elongation of 10% or more. [0024] (iii) The
copper alloy material comprises an electric conductivity of 40%
IACS or more. [0025] (2) According to another aspect of the
invention, a copper alloy material for electric parts
comprises:
[0026] 1.0 to 5.0 mass % of Ni;
[0027] 0.2 to 1.0 mass % of Si;
[0028] 0.05 to 2.0 mass % of Sn;
[0029] 0.1 to 5.0 mass % of Zn;
[0030] 0.01 to 0.3 mass % of P;
[0031] 0.05 to 1.0 mass % of at least one of Fe and Co;
[0032] 0.01 to 1.0 mass % of at least one of Mg, Ti, Cr and Zr
and
[0033] the balance consisting of Cu and an unavoidable
impurity,
[0034] wherein a ratio, (Ni+Fe+Co)/(Si+P), between a total mass of
Ni, Fe and Co and a total mass of Si and P is 4 or more and 10 or
less.
[0035] In the above invention, the following modifications can be
made. [0036] (vi) The copper alloy material comprises a tensile
strength of 700 N/mm.sup.2 or more. [0037] (v) The copper alloy
material comprises an elongation of 10% or more. [0038] (vi) The
copper alloy material comprises an electric conductivity of 40%
IACS or more. [0039] (3) According to another aspect of the
invention, a method of making the copper alloy material for
electric parts as defined in above (1) comprises:
[0040] preparing a copper alloy raw material with the same
composition and the same mass ratio as defined in above (1);
[0041] a first cold rolling step that the copper alloy raw material
is cold-rolled down to a thickness of 1.1 to 1.3 times a target
thickness of a final product;
[0042] a first heat treatment step that the cold-rolled material in
the first cold rolling step is heated up to 700 to 850.degree. C.
and then cooled to 300.degree. C. or less at a cooling rate of
25.degree. C./min or more;
[0043] a second cold rolling step that the treated material in the
first heat treatment step is cold-rolled down to the target
thickness; and
[0044] a second heat treatment step that the cold-rolled material
in the second cold rolling step is heated up to 400 to 500.degree.
C. and held for 30 min. to 3 hrs. [0045] (4) According to another
aspect of the invention, a method of making the copper alloy
material for electric parts as defined in above (2) comprises:
[0046] preparing a copper alloy raw material with the same
composition and the same mass ratio as defined in above (2);
[0047] a first cold rolling step that the copper alloy raw material
is cold-rolled down to a thickness of 1.1 to 1.3 times a target
thickness of a final product;
[0048] a first heat treatment step that the cold-rolled material in
the first cold rolling step is heated up to 700 to 850.degree. C.
and then cooled to 300.degree. C. or less at a cooling rate of
25.degree. C./min or more;
[0049] a second cold rolling step that the treated material in the
first heat treatment step is cold-rolled down to the target
thickness; and
[0050] a second heat treatment step that the cold-rolled material
in the second cold rolling step is heated up to 400 to 500.degree.
C. and held for 30 min. to 3 hrs.
<Advantages of the Invention>
[0051] A copper alloy material for electric parts, such as a
terminal, connector and lead frame, can be provided that is
excellent in mechanical strength such as tensile strength and 0.2%
yield strength (herein called simply "yield strength"), in
elongation, in electric conductivity and in bending workability to
show reduced anisotropy in the bending process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0052] The preferred embodiments according to the invention will be
explained below referring to the drawings, wherein:
[0053] FIG. 1 is a flowchart showing a method of making a copper
alloy material for electric parts in a preferred embodiment
according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
Composition of Copper Alloy Material for Electric Parts
[0054] Copper alloy materials for electric parts of this embodiment
comprise, in average composition, 1.0 to 5.0 mass % of Ni, 0.2 to
1.0 mass % of Si, 0.05 to 2.0 mass % of Sn, 0.1 to 5.0 mass % of
Zn, 0.01 to 0.3 mass % of P, 0.05 to 1.0 mass % (=total mass %) of
at least one of Fe and Co, and the balance of Cu and an unavoidable
impurity, wherein the ratio between a total mass of Ni, Fe and Co
and a total mass of Si and P is to be (Ni+Fe+Co)/(Si+P)=4 or more
and 10 or less.
[0055] The reasons for adding the alloy elements to compose the
copper alloy material for electric parts and for limiting the
content thereof are as follows.
[0056] The Ni, Fe and Co can be dispersed and precipitated in the
material while forming a Si compound or a P compound when it is
added therein together with Si and P. Although the conventional
Cu--Ni--Si alloys have an enhanced mechanical strength by
dispersing and precipitating a Ni--Si compound, this embodiment can
have a further enhanced mechanical strength by the effects of
precipitations, i.e., a Ni--P compound, and a Si compound and/or a
P compound with Fe and Co in addition to the Ni--Si compound.
[0057] Thereupon, by defining the content (the addition amount) and
the composition ratio of Ni, Fe, Co, Si and P to be in a specific
range, the mechanical strength and spring property can be enhanced
by the enhanced dispersion effect of the precipitations while
suppressing the amount of solid-solution element in the Cu matrix
that may reduce the electric conductivity.
[0058] If the Si is added less than 0.02 mass %, a sufficient
amount of the Si compound cannot be formed and, thus, the
sufficient mechanical strength and spring property cannot be
obtained. If it is added more than 1.0 mass %, the electric
conductivity will be badly affected and a crack may be arisen which
is caused by the segregation of Si compound in the process of
forming the copper alloy raw material (e.g., in the casting thereof
or in the hot working after the casting). Thus, the composition
ratio of Si is defined to be 0.2 to 1.0 mass %, preferably to be
0.4 to 0.7 mass %.
[0059] If the P is less than 0.01 mass %, the P compound cannot be
effectively formed. If it is added more than 0.3 mass %, a crack
may be arisen which is caused by the segregation of P compound in
the process of forming the copper alloy raw material (e.g., in the
casting thereof). Thus, the composition ratio of P is defined to be
0.01 to 0.3 mass %, preferably to be 0.1 to 0.2 mass %.
[0060] It is needed that the composition of Ni is 1.0 to 5.0 mass
%, the total composition of Fe and Co is 0.05 to 1.0 mass %, and
the ratio (Ni+Fe+Co)/(Si+P) between a total mass of Ni, Fe and Co
and a total mass of Si and P is 4 or more and 10 or less, so as to
secure simultaneously a high mechanical strength and a high
electric conductivity while forming effectively the compound in
relation to the above composition of Si and P. If the content of
Ni, Fe and Co is less than the lower limit of the above
composition, the amount of the compound formed will be
insufficient, which causes a lack of mechanical strength and spring
property. If the content of Ni, Fe and Co is more than the upper
limit thereof, excessive Ni, Fe and Co will be dissolved into the
Cu matrix as a solid solution to degrade the electric conductivity.
Further, if the ratio (Ni+Fe+Co)/(Si+P) is less than 4, Si and P
are excessive and if more than 10, Ni, Fe and Co are excessive by
contrast. Since such an excessive component exists in
solid-solution state in the Cu matrix, the electric conductivity
will be degraded. It is preferably defined that the composition of
Ni is 2.5 to 3.5 mass %, the total composition of Fe and Co is 0.3
to 0.7 mass %, and the ratio (Ni+Fe+Co)/(Si+P) is 4 or more and 7
or less.
[0061] Further, to the above composition, 0.05 to 2.0 mass % of Sn
and 0.1 to 5.0 mass % of Zn are added.
[0062] The Sn has a significant effect to enhance the mechanical
strength and spring property. Further, it has an effect to improve
the stress-relaxation resistance (=heat resistance) in a
temperature environment of about 150.degree. C., and therefore it
is an effective additive in the material for electric parts.
However, if the content thereof is less than 0.05 mass %, the
effects are not sufficient. If it is added more than 2.0 mass %, it
has a negative affection to degrade the electric conductivity.
Thus, the composition of Sn is preferably to be 0.05 to 2.0mass %,
more preferably to be 0.3 to 1.0 mass %.
[0063] The Zn has an effect to enhance the mechanical strength and
spring property. Further, it has a significant effect to enhance
the migration resistance. Still further, it has an effect to
improve the solder wettability and cohesion to a Sn plating which
are needed in the material for electric and electronic parts.
However, if the content thereof is less than 0.1 mass %, the
effects are not sufficient. If it is added more than 5.0 mass %, it
has a negative affection to degrade the electric conductivity.
Thus, the composition of Zn is preferably to be 0.1 to 5.0 mass %,
more preferably to be 0.3 to 2.0 mass %.
Second Embodiment
Composition of Copper Alloy Material for Electric Parts
[0064] Copper alloy materials for electric parts of this embodiment
comprise, in average composition, 1.0 to 5.0 mass % of Ni, 0.2 to
1.0 mass % of Si, 0.05 to 2.0 mass % of Sn, 0.1 to 5.0 mass % of
Zn, 0.01 to 0.3 mass % of P, 0.05 to 1.0 mass % (=total mass %) of
at least one of Fe and Co, 0.01 to 1.0 mass % of at least one of
Mg, Ti, Cr and Zr, and the balance of Cu and an unavoidable
impurity, wherein the ratio between a total mass of Ni, Fe and Co
and a total mass of Si and P is to be (Ni+Fe+Co)/(Si+P)=4 or more
and 10 or less.
[0065] The reasons for adding the alloy elements to compose the
copper alloy material for electric parts and for limiting the
content thereof are as follows.
[0066] The reasons for adding Ni, Si, Sn, Zn, P, Fe and Co and for
limiting the content (=addition amount) and composition ratio
thereof are the same as described in the first embodiment.
[0067] In addition, the reason why at least one of Mg, Ti, Cr and
Zr is added 0.01 to 1.0 mass % in total is that additional
excellent properties can be obtained. These elements have effects
to improve further the mechanical strength, spring property,
migration resistance, and heat resistance, and have only a small
affection to lower the electric conductivity. Therefore, they are
effective as an additive to facilitate the effects of the
aforementioned elements in the first embodiment. However, if the
total content thereof is less than 0.01 mass %, the sufficient
effect cannot be expected. If it is added more than 1.0 mass %, a
negative affection may appear such as deterioration in casting
property in the process of forming a copper alloy raw material.
Thus, the composition of Mg, Ti, Cr and Zr is in total to be 0.01
to 1.0 mass %, more preferably to be 0.1 to 0.3 mass %.
Method of Making the Copper Alloy Material for Electric Parts
[0068] FIG. 1 is a flowchart showing a method of making a copper
alloy material for electric parts in the preferred embodiment
according to the invention.
[0069] The above mentioned copper alloy material of the first and
second embodiments can be made, after preparing the copper alloy
raw material with the average composition as defined earlier, by
conducting: the first cold rolling step that the copper alloy raw
material thus formed is cold-rolled down to 1.1 to 1.3 times
thicker than a target thickness of a final product; the first heat
treatment step that the material after the first cold rolling step
is heated up to 700 to 850.degree. C. and then cooled to less than
300.degree. C. at a cooling rate of 25.degree. C./min or more; the
second cold rolling step that the material after the first heat
treatment step is cold-rolled down to the target thickness of the
final product; and the second heat treatment step that the material
after the second cold rolling step is heated up to 400 to
500.degree. C. and kept for 30 minutes to 3 hours. Meanwhile, the
copper alloy raw material can be, for example, prepared by
conducting an alloy casting step and then a hot working step.
[0070] First Cold Rolling Step
[0071] In the first cold rolling step, the copper alloy raw
material prepared is cold-rolled down to 1.1 to 1.3 times thicker
than the target thickness of the final product. This process (step)
promotes the recrystallization in the following first heat
treatment and allows the formation of the grain structure with
equalized grain size after the recrystallization. The reason why
the material thickness after the rolling is defined to be 1.1 to
1.3 times the target thickness of final product is to introduce a
proper amount of lattice defect such as a dislocation in the cold
rolling (i.e., the second cold rolling step) after the first heat
treatment step as described later. If the material thickness is
more than the defined thickness, excessive lattice defects will be
introduced by the cold rolling (i.e., the second cold rolling step)
after the first heat treatment step and, therefore, the elongation
property of the final product is lowered and the anisotropy of the
elongation property is arisen depending on the rolling direction in
the bending process, that causes to degrade the bending workability
of the product. If the material thickness is less than the defined
thickness, the lattice defect will be insufficiently introduced in
the cold rolling (i.e., the second cold rolling step) after the
first heat treatment step and, therefore, the mechanical strength
such as tensile strength and yield strength is lowered.
[0072] First Heat Treatment Step
[0073] In the first heat treatment step, in order to carry out the
solution heat treatment (solid solution heat treatment), the copper
alloy material after the first cold rolling step is heated up to
700 to 850.degree. C. and then cooled to less than 300.degree. C.
at a cooling rate of 25.degree. C./min or more. Preferably, it is
heated up to 770 to 850.degree. C. and then cooled to less than
300.degree. C. at a cooling rate of 150.degree. C./min or more.
Although the holding time of the heating is not defined, it is
preferably shorter in consideration of the productivity and the
material only has to be held at the defined temperature
substantially for 1 sec. or more. The solution heat treatment in
this step is intended to disperse (dissolve) uniformly the alloy
component into the copper matrix so as to disperse and precipitate
uniformly and finely the alloy component in the final product.
Thereby, the nonuniform precipitation that may be formed in the
process of preparing the copper alloy raw material can be dissolved
again in the copper matrix by the solid solution heat treatment. By
defining the heating temperature to be 700.degree. C. or more, the
formation of solid solution can be sufficiently progressed. By
defining the cooling rate to be 25.degree. C./min or more, a coarse
precipitation (grain growth of the precipitation) can be prevented
from being formed again during the cooling process.
[0074] Further, by the first heat treatment step, the grain
distorted by the intensive cold working (i.e., the first cold
rolling step) can be recrystallized and changed into a grain
structure with less anisotropy, and the elongation property of the
rolled material can be recovered to provide a good bending
workability. If the heating temperature is more than 850.degree.
C., a coarsening of the grain (i.e., excessive recrystallization or
exaggerated grain growth) may be occurred resulting in the
degradation of the bending workability. Therefore, the upper limit
of the heating temperature is defined to be 850.degree. C.
[0075] Second Cold Rolling Step
[0076] In the second cold rolling step, the copper alloy material
after the first heat treatment is cold-rolled until having the
target thickness of final product. Thereby, the lattice defect
which becomes a starting point (i.e., a nucleation site) for
forming the precipitation in the heat treatment (i.e., the second
heat treatment step) as described later can be introduced suitably
into the material. Thus, the formation of uniform and fine
precipitation can be promoted in the following heat treatment
(i.e., the second heat treatment step), and the mechanical strength
can be enhanced.
[0077] Second Heat Treatment Step
[0078] In the second heat treatment step, in order to achieve the
age-hardening (precipitation-hardening), the copper alloy material
after the second cold rolling step is heated up to 400 to
500.degree. C. and held for 30 minutes to 3 hours. Preferably, it
is heated up to 430 to 480.degree. C. and held for 1 to 2 hours.
Thereby, the Ni, Fe and Co can form compounds with Si and P, which
can be dispersed and precipitated in the copper matrix to have
simultaneously the high mechanical strength and good electric
conductivity. If the treatment conditions are higher and longer
than the defined range, 400 to 500.degree. C. and 30 minutes to 3
hours, the precipitation may be coarsened to fail to have the
sufficient mechanical strength. If the treatment conditions are
lower and shorter than the defined range, the precipitation may be
insufficiently progressed to fail to have the sufficient electric
conductivity and mechanical strength.
Effects of the Embodiment
[0079] The effects of the embodiment are as follows. [0080] (1) The
copper alloy material for electric parts such as a terminal,
connector and lead frame can be obtained which has a tensile
strength of 700 N/mm.sup.2 or more, a yield strength of 650
N/mm.sup.2 or more, an elongation of 10% or more, an electric
conductivity of 40% IACS or more, and reduced anisotropy in the
bending process (i.e., good bending workability). [0081] (2)
Because of the excellent properties as described in (1), electronic
parts such as a terminal, connector and lead frame can have an
expanded choice of design even when it would be downsized all the
more. [0082] (3) Although it has the excellent properties as
described in (1), it can be made for almost the same cost as the
conventional ones.
EXAMPLES
[0083] Examples of the invention will be described below, but the
invention is not limited by these examples.
Example 1 (=Sample No. 1)
[0084] A copper alloy which comprises Ni: 3.0 mass %, Si: 0.5 mass
%, P: 0.15 mass %, Fe: 0.15 mass %, Co: 0.15 mass %, Sn: 1.0 mass
%, and Zn: 1.5 mass % in an oxygen-free copper matrix is molten in
a RF melting furnace and then cast into an ingot with a diameter of
30 mm and a length of 250 mm.
[0085] The ingot is heated to 850.degree. C. and extruded
(hot-worked) into a plate-like copper alloy raw material with a
width of 20 mm and a thickness of 8 mm. Then, it is cold-rolled
down to a thickness of 0.36 mm (the first cold rolling step). Then,
the cold-rolled material is held at 800.degree. C. for 10 min. and
then is quenched in water to be cooled down to a room temperature
(about 20.degree. C.) at a rate of about 300.degree. C./min (the
first heat treatment step). Then, the cooled material is
cold-rolled down to a thickness of 0.3 mm (the second cold rolling
step), and then heated at 470.degree. C. for 2 hours (the second
heat treatment step) (Sample No. 1).
[0086] Sample No. 1 thus made is measured in relation to the
properties of tensile strength, yield strength, elongation and
electric conductivity. The tensile strength, yield strength and
elongation are measured based on JIS Z 2241 and the electric
conductivity is measured based on JIS H 0505. The measurement
results are shown in Table 2.
[0087] As shown in Table 2, it is confirmed that Sample No. 1 has
good properties, i.e., a tensile strength of 740 N/mm.sup.2, a
yield strength of 684 N/mm.sup.2, an elongation of 12% and an
electric conductivity of 42% IACS, which are suited to the object
of the invention.
Examples 2 to 9 (=Sample Nos. 2 to 9)
[0088] Copper alloys with compositions as Sample Nos. 2 to 9 in
Table 1 are cast like Example 1 (=Sample No. 1), rolled into
samples with a thickness of 0.3 mm in the same processes as Example
1 (=Sample No. 1), subjected to the second heat treatment (to be
kept at 470.degree. C. for 2 hours) like Example 1 (=Sample No. 1).
Sample Nos. 2 to 9 are measured in relation to the properties of
tensile strength, yield strength, elongation and electric
conductivity like Example 1 (=Sample No. 1). The measurement
results are shown in Table 2.
[0089] As shown in Table 2, it is confirmed that Sample Nos. 2 to 9
have good properties suited to the object of the invention.
Further, it is confirmed that Sample Nos. 6 to 9, each of which
contains 0.1 mass % of Mg, Ti, Cr or Zr in addition to the
composition of Sample No. 1, all have a tensile strength and yield
strength higher than Sample No. 1 and that, thus, the additive
elements are effective.
[0090] Sample No. 4, which is slightly lower than the more
preferred composition ratio described earlier in relation to the Ni
content, Si content and the total content of Fe and Co, has a
tensile strength and yield strength slightly lower than Sample No.
1 while it has an elongation and electric conductivity higher than
Sample No. 1.
[0091] Sample No. 5, which is slightly higher than the more
preferred composition ratio described earlier in relation to the Ni
content, has an elongation and electric conductivity slightly lower
than Sample No. 1 while it has a tensile strength and yield
strength higher than Sample No. 1.
[0092] However, it is confirmed that both of Sample Nos. 4 and 5
can sufficiently secure the expected effects (i.e., a tensile
strength of 700 N/mm.sup.2 or more, a yield strength of 650
N/mm.sup.2 or more, an elongation of 10% or more, and an electric
conductivity of 40% IACS or more).
Comparative Examples 1 to 13 (=Sample Nos. 10 to 22)
[0093] The reasons for defining the alloy composition in the copper
alloy material of the invention are described below as compared
with Comparative examples 1 to 13.
[0094] Copper alloys with compositions as Sample Nos. 10 to 22
(which correspond to Comparative examples 1 to 13, respectively) in
Table 1 are cast like Example 1 (=Sample No. 1), rolled into
samples with a thickness of 0.3 mm in the same processes as Example
1 (=Sample No. 1), subjected to the second heat treatment (to be
kept at 470.degree. C. for 2 hours) like Example 1 (=Sample No.
1).
[0095] Sample Nos. 10 to 22 obtained are measured in relation to
the properties of tensile strength, yield strength, elongation and
electric conductivity like Example 1 (=Sample No. 1). The
measurement results are shown in Table 2.
[0096] Sample Nos. 10 to 15 are out of the invention-defined range
in relation to the content of Ni and Si. In Sample Nos. 10 and 14,
a crack is observed in the ingot since the content of Si is too
large. In Sample No. 12, due to the excessive content of Ni, the
electric conductivity is degraded even though the tensile strength
is high. In Sample Nos. 11, 13 and 15, where one or both of the Ni
and Si contents is too small, the sufficient tensile strength
cannot be obtained.
[0097] In Sample No. 16, the amount of P is excessive. In this
case, a crack is observed in the ingot like the case of excessive
content of Si (Sample Nos. 10 and 14). In Sample No. 17, the amount
of Fe and Co is excessive. In these cases, the electric
conductivity is degraded even though the tensile strength is
high.
[0098] Sample Nos. 18 and 19 are out of the invention-defined range
in relation to the ratio, (Ni+Fe+Co)/(Si+P), of the total mass of
Ni, Fe and Co and the total mass of Si and P. In Sample No. 18 that
the ratio is smaller than the invention-defined range, the electric
conductivity is degraded and both the tensile strength and yield
strength are not high. Similarly, in Sample No. 19 that the ratio
is larger than the invention-defined range, the electric
conductivity is degraded and both the tensile strength and yield
strength are not high.
[0099] In Sample No. 20, the content of Sn is excessive. In Sample
No. 21, the content of Zn is excessive. In both cases, the electric
conductivity is degraded even though the tensile strength is high.
In Sample No. 22, the content of Mg is excessive. In this case, the
electric conductivity is deteriorated and the elongation is not
high. TABLE-US-00001 TABLE 1 Composition (mass %) (Ni + Fe + Co)/
Kind Sample No. Ni Si P Fe Co Sn Zn Other Cu (Si + P) ratio Example
1 1 3.0 0.5 0.15 0.15 0.15 1.0 1.5 -- balance 5.1 2 2 3.0 0.5 0.15
0.3 -- 1.0 1.5 -- balance 5.1 3 3 3.0 0.5 0.15 -- 0.3 1.0 1.5 --
balance 5.1 4 4 2.0 0.3 0.1 0.1 0.1 1.0 1.5 -- balance 5.5 5 5 4.0
0.6 0.2 0.2 0.2 1.0 1.5 -- balance 5.5 6 6 3.0 0.5 0.15 0.15 0.15
1.0 1.5 0.1Mg balance 5.1 7 7 3.0 0.5 0.15 0.15 0.15 1.0 1.5 0.1Ti
balance 5.1 8 8 3.0 0.5 0.15 0.15 0.15 1.0 1.5 0.1Cr balance 5.1 9
9 3.0 0.5 0.15 0.15 0.15 1.0 1.5 0.1Zr balance 5.1 Comparative 1 10
8.0 1.4 0.2 0.15 0.15 1.0 1.5 -- balance 5.2 example 2 11 0.5 0.1
0.05 0.15 0.15 1.0 1.5 -- balance 5.3 3 12 8.0 0.8 0.2 0.15 0.15
1.0 1.5 -- balance 8.3 4 13 0.5 0.3 0.05 0.5 0.5 1.0 1.5 -- balance
4.3 5 14 5.0 1.2 0.15 0.5 0.5 1.0 1.5 -- balance 4.4 6 15 1.5 0.1
0.1 0.1 0.1 1.0 1.5 -- balance 8.5 7 16 4.0 0.5 0.5 0.15 0.15 1.0
1.5 -- balance 4.3 8 17 3.0 0.5 0.15 1.0 1.0 1.0 1.5 -- balance 7.7
9 18 1.5 0.5 0.15 0.1 0.05 1.0 1.5 -- balance 2.5 10 19 4.0 0.3 0.1
0.4 0.4 1.0 1.5 -- balance 12.0 11 20 3.0 0.5 0.15 0.15 0.15 4.0
1.5 -- balance 5.1 12 21 3.0 0.5 0.15 0.15 0.15 1.0 8.0 -- balance
5.1 13 22 3.0 0.5 0.15 0.15 0.15 1.0 1.5 2.0Mg balance 5.1
[0100] TABLE-US-00002 TABLE 2 Tensile Electric Sample Crack of
strength Yield strength Elongation conductivity Kind No. ingot
(N/mm.sup.2) (N/mm.sup.2) (%) (% IACS) Example 1 1 no 740 684 12 42
2 2 no 736 678 12 42 3 3 no 738 680 12 42 4 4 no 708 654 14 44 5 5
no 772 720 10 41 6 6 no 760 706 12 42 7 7 no 776 724 12 41 8 8 no
755 696 12 42 9 9 no 752 694 12 42 Comparative 1 10 found -- -- --
-- example 2 11 no 518 470 14 55 3 12 no 734 670 8 33 4 13 no 580
528 12 40 5 14 found -- -- -- -- 6 15 no 588 536 14 42 7 16 found
-- -- -- -- 8 17 no 752 690 10 36 9 18 no 574 524 14 38 10 19 no
654 602 8 30 11 20 no 778 722 10 33 12 21 no 764 710 10 33 13 22 no
780 726 8 35
Comparative Examples 14 to 19 (=Sample Nos. 23 to 28)
[0101] The reasons for defining the conditions in the method of
making the copper alloy material of the invention are described
below as compared with Comparative examples 14 to 19.
[0102] Sample Nos. 23 to 28 (which correspond to Comparative
examples 14 to 19, respectively) are made such that the copper
alloys with the same composition as Sample No. 1 in Example 1 are
processed in similar processes to Example 1, where the thickness
ratio of the cold-rolled material in the first cold rolling step
and the final product, and the heating conditions of the first and
second heat treatment steps are shown in Table 3.
[0103] Sample Nos. 23 to 28 obtained are measured in relation to
the properties of tensile strength, yield strength, elongation and
electric conductivity like Example 1 (=Sample No. 1).
[0104] Further, a bending test is conducted to evaluate the bending
workability. The bending test is based on a W-bending test as set
forth in JIS H 3110 and is conducted such that the sample is bent
at an angle of 90 degrees with a bend radius of 0 mm and then the
surface of bent portion is observed to check the existence of a
crack. In detail, the bending test is conducted in both cases that
the direction of bending axis is orthogonal to the rolling
direction, and that the direction of bending axis is parallel to
the rolling direction. Here, when no crack formation is observed in
both directions (i.e., not depending on the rolling direction), the
sample is evaluated matter as "Good". When a crack formation is
observed in either direction, the sample is evaluated as "Not
good". The measurement/observation results are shown in Table
4.
[0105] It is confirmed that Sample No. 1 (=Example 1) can have a
high tensile strength of more than 700 N/mm.sup.2, a high yield
strength of more than 650 N/mm.sup.2 , a good elongation of more
than 10% and a good electric conductivity of more than 40% IACS as
well as good bending workability, while Sample Nos. 23 to 28
(=Comparative examples 14 to 19) are significantly insufficient in
either of the tested properties (i.e., tensile strength, yield
strength, elongation, electric conductivity and bending
workability).
[0106] Sample Nos. 23 and 24 are out of the invention-defined range
in relation to the thickness ratio between the cold-rolled material
in the first cold rolling step and the final product. If the
cold-rolled material in the first cold rolling step is too thin
(i.e., the thickness ratio is less than 1.1) (Sample No. 23), the
defects introduced in the second cold rolling step is reduced and,
therefore, the yield strength of the final product remains low and
the tensile strength is also low. By contrast, if the cold-rolled
material in the first cold rolling step is too thick (i.e., the
thickness ratio is more than 1.3) (Sample No. 24), the defects
introduced in the second cold rolling step is excessive and,
therefore, the elongation of the final product is degraded and
anisotropy in the bending appears to deteriorate the bending
workability (i.e., a crack is formed when the sample is bent with
the bending axis parallel to the rolling direction).
[0107] Sample Nos. 25 and 26 are out of the invention-defined range
in relation to the heating temperature of the first heat treatment
step. If the heating temperature is too low or high, both the
tensile strength and the yield strength are low. If the heating
temperature is too high (Sample No. 26), the elongation, the
electric conductivity and the bending workability are low as well
as the tensile strength and the yield strength.
[0108] Sample Nos. 27 and 28 are out of the invention-defined range
in relation to the heating temperature of the second heat treatment
step. If the heating temperature is too low (Sample No. 27), the
electric conductivity is low, the tensile strength, the yield
strength and the elongation are insufficient, and the bending
workability is lowered. If the heating temperature is too high
(Sample No. 28), the tensile strength and the yield strength are
insufficient even though the electric conductivity is high.
TABLE-US-00003 TABLE 3 Thickness ratio of first cold-rolled
material and First heat treatment Second heat treatment kind Sample
No. final product heating conditions heating conditions Remarks
Example 1 1 1.20:1 800.degree. C. .times. 10 min 470.degree. C.
.times. 2 h -- Comparative 14 23 1.07:1 800.degree. C. .times. 10
min 470.degree. C. .times. 2 h Same example composition as No. 1 15
24 1.67:1 800.degree. C. .times. 10 min 470.degree. C. .times. 2 h
Same composition as No. 1 16 25 1.20:1 600.degree. C. .times. 10
min 470.degree. C. .times. 2 h Same composition as No. 1 17 26
1.20:1 950.degree. C. .times. 10 min 470.degree. C. .times. 2 h
Same composition as No. 1 18 27 1.20:1 800.degree. C. .times. 10
min 350.degree. C. .times. 2 h Same composition as No. 1 19 28
1.20:1 800.degree. C. .times. 10 min 550.degree. C. .times. 2 h
Same composition as No. 1
[0109] TABLE-US-00004 TABLE 4 Tensile strength Yield strength
Elongation Electric conductivity Bending Kind Sample No.
(N/mm.sup.2) (N/mm.sup.2) (%) (% IACS) workability Example 1 1 740
684 12 42 Good Comparative 14 23 670 558 16 40 Good example 15 24
750 688 9 43 Not good 16 25 574 504 12 42 Good 17 26 688 630 8 36
Not good 18 27 590 532 8 33 Not good 19 28 578 510 14 44 Good
[0110] Although the invention has been described with respect to
the specific embodiments for complete and clear disclosure, the
appended claims are not to be thus limited but are to be construed
as embodying all modifications and alternative constructions that
may occur to one skilled in the art which fairly fall within the
basic teaching herein set forth.
* * * * *