U.S. patent application number 13/486861 was filed with the patent office on 2012-09-27 for copper alloy sheet material having a low young's modulus and method of producing the same.
Invention is credited to Tatsuhiko EGUCHI, Hiroshi KANEKO, Koji SATO.
Application Number | 20120241056 13/486861 |
Document ID | / |
Family ID | 44114980 |
Filed Date | 2012-09-27 |
United States Patent
Application |
20120241056 |
Kind Code |
A1 |
SATO; Koji ; et al. |
September 27, 2012 |
COPPER ALLOY SHEET MATERIAL HAVING A LOW YOUNG'S MODULUS AND METHOD
OF PRODUCING THE SAME
Abstract
{Problems} To provide a copper alloy material, having a low
Young's modulus that is required of electrical or electronic parts,
such as connectors. {Means to solve} A copper alloy sheet material
for electrical or electronic parts, having an alloy composition
containing any one or both of Ni and Co in an amount of 0.5 to 5.0
mass % in total, and Si in an amount of 0.2 to 1.5 mass %, with the
balance being Cu and inevitable impurities, wherein the copper
alloy sheet material has a 0.2% proof stress in the rolling
direction of 500 MPa or more, an electrical conductivity of 30%
IACS or more, a Young's modulus of 110 GPa or less, and a factor of
bending deflection of 105 GPa or less.
Inventors: |
SATO; Koji; (Tokyo, JP)
; KANEKO; Hiroshi; (Tokyo, JP) ; EGUCHI;
Tatsuhiko; (Tokyo, JP) |
Family ID: |
44114980 |
Appl. No.: |
13/486861 |
Filed: |
June 1, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/JP2010/071517 |
Dec 1, 2010 |
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13486861 |
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Current U.S.
Class: |
148/554 ;
148/414 |
Current CPC
Class: |
C22C 9/10 20130101; B21B
2003/005 20130101; C22C 9/06 20130101; H01B 1/026 20130101; C22F
1/08 20130101 |
Class at
Publication: |
148/554 ;
148/414 |
International
Class: |
C22F 1/08 20060101
C22F001/08; C22C 9/00 20060101 C22C009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 2, 2009 |
JP |
2009-274996 |
Claims
1-9. (canceled)
10. A copper alloy sheet material for electrical or electronic
parts, having an alloy composition containing any one or both of Ni
and Co in an amount of 0.5 to 5.0 mass % in total, Si in an amount
of 0.2 to 1.5 mass %, optionally Cr in an amount of 0.05 to 0.5
mass %, and optionally at least one selected from the group
consisting of Zn, Sn, Mg, Ag, Mn, and Zr in an amount of 0.01 to
1.0 mass % in total, with the balance being Cu and inevitable
impurities, wherein the copper alloy sheet material has a 0.2%
proof stress in the rolling direction of 500 MPa or more, an
electrical conductivity of 30% IACS or more, a Young's modulus of
110 GPa or less, and a factor of bending deflection of 105 GPa or
less.
11. The copper alloy sheet material for electrical or electronic
parts according to claim 10, wherein the copper alloy sheet
material has an area ratio of (1 0 0) plane oriented toward the
rolling direction, which is obtained by analyzing the copper alloy
sheet material with EBSD, is 30% or more.
12. The copper alloy sheet material for electrical or electronic
parts according to claim 10, wherein the copper alloy sheet
material has an area ratio of (1 1 1) plane oriented toward the
rolling direction, which is obtained by analyzing the copper alloy
sheet material with EBSD, is 15% or less.
13. The copper alloy sheet material for electrical or electronic
parts according to claim 11, wherein the copper alloy sheet
material has an area ratio of (1 1 1) plane oriented toward the
rolling direction, which is obtained by analyzing the copper alloy
sheet material with EBSD, is 15% or less.
14. A connector, which is composed of the copper alloy sheet
material for electrical or electronic parts according to claim
10.
15. A method of producing the copper alloy sheet material for
electrical or electronic parts according to claim 10, containing,
in this order, the steps of: subjecting a copper alloy to give the
alloy composition to casting; hot-rolling; cold-rolling 1 at a
rolling ratio of 70% or higher; intermediate annealing at 300 to
800.degree. C. for 5 seconds to 2 hours; cold-rolling 2 at a
rolling ratio of 3 to 60%; solution heat treatment at 600 to
1,000.degree. C. for 5 seconds to 300 seconds; aging heat treatment
at 400 to 600.degree. C. for 0.5 hours to 8 hours; finish
cold-rolling at a working ratio of 50% or less; and low-temperature
annealing at 300 to 700.degree. C. for 10 seconds to 2 hours,
wherein the method of producing further contains, conducting at
least any one or both of the following steps [1] and [2]: [1]
slowly cooling at a cooling speed of 5 K/second or less to a
temperature of 350.degree. C., after the hot-rolling; and [2]
carrying out the intermediate annealing and the cold-rolling 2,
repeatedly two times or more.
Description
TECHNICAL FIELD
[0001] The present invention relates to a copper alloy sheet
material having high mechanical strength and high electrical
conductivity, which is suitable as a material for electrical or
electronic parts, such as connectors, and further having a low
Young's modulus, and the present invention also relates to a method
of producing the same.
BACKGROUND ART
[0002] In recent years, wirings of various electrical or electronic
equipments have been subjected to further intricacy and higher
integration, due to the development of electronics industries.
Along this trend, the opportunity for copper alloys to be used for
electrical or electronic parts is ever increasing. In particular,
electrical or electronic parts, such as connectors, are demanded to
narrow the pitch, lower the height, enhance the reliability higher,
and lower the costs. Thus, in order to satisfy these demands,
copper alloy sheet materials that can be used in electrical or
electronic parts, such as connectors, are required to have high
mechanical strength and high electrical conductivity and to
simultaneously have excellent press formability, so as to be formed
into thin sheets and to be pressed into complicated shapes.
[0003] In order to use as materials for terminals, it is preferable
for the materials to have a tensile strength in the rolling
direction (RD) of 500 MPa or more, as a mechanical strength that
does not cause deformation upon putting-in and pulling-out
(insertion and extraction) of the terminals or against bending
thereof, and to have an electrical conductivity of 30% IACS or
more, so as to suppress the Joule heat generation caused by
electric current conduction.
[0004] Furthermore, hitherto, the material for connectors has been
required to have a large Young's modulus so that the resultant
connectors become small-sized, and a large stress may be obtained
with a small displacement. However, more strict dimensional
accuracy is demanded for terminals themselves, and more strict
criteria are applied to, such as the operation control in pressing
or molding technology, or the control criteria, for example, of the
sheet thickness of the material for connectors or fluctuations in
the residual stress, which resulted in an increase in the costs
conversely. Under the situations, recently, there has been a demand
for a design that allows dimensional fluctuations, by adopting a
structure which undergoes large spring displacement, by using a
material for connectors small in Young's modulus. Thus, there has
been a demand for the material having a Young's modulus in the
rolling direction of 110 GPa or less, preferably 100 GPa or
less.
[0005] So far, brass, phosphor bronze, and the like have been
generally used as the materials for connectors. Both brass and
phosphor bronze have a Young's modulus in the rolling direction of
about 110 to 120 GPa, which is smaller as compared with the Young's
modulus of 128 GPa of pure copper, and brass and phosphor bronze
are widely used as low Young's modulus materials. However, these
copper alloys each have an electrical conductivity as low as 30%
IACS or less, and may not be used for connectors in the
applications where large electric current is to pass. Thus,
attention has been paid to Corson-based alloy, which has a moderate
degree of electrical conductivity, and the amount of use of the
alloy is increasing. However, this Corson-based alloy has a Young's
modulus of about 130 GPa, and due to this, there is a demand for
lowering of the Young's modulus of connector materials.
Furthermore, depending on a designer of connectors, there are cases
where connectors are designed based not on the Young's modulus but
on the factor of bending deflection (the modulus of longitudinal
elasticity upon a bending test), and lowering of the factor of
bending deflection is demanded. Generally, Young's modulus
represents the modulus of longitudinal elasticity under tensile
stress, and the factor of bending deflection represents the modulus
of longitudinal elasticity under the complex stress of compressive
stress and tensile stress upon bending. Although the values of the
Young's modulus and the factor of bending deflection are different
from each other, if the Young's modulus is low, the factor of
bending deflection tends to be a low value.
[0006] A lowering of the Young's modulus and a lowering of the
factor of bending deflection are achieved not only by adding zinc
(Zn) or phosphor (P) to copper, but also by controlling the crystal
orientation. For example, as described in Patent Literature 1 and
Patent Literature 2, when pure copper is recrystallized by a heat
treatment after rolling at a high working ratio, cube orientation
(1 0 0) <1 0 0> increases in the direction (ND) normal to the
rolling direction of the sheet material, and thereby the Young's
modulus lowers, while flexibility becomes favorable. However, in a
Corson-based alloy, if simply the cold-rolling ratio before
recrystallization is increased, the cube orientation is not
increased, and it is difficult to control the Young's modulus.
CITATION LIST
Patent Literatures
[0007] Patent Literature 1: JP-A-55-54554 ("JP-A" means unexamined
published Japanese patent application) [0008] Patent Literature 2:
Japanese Patent No. 3009383
SUMMARY OF INVENTION
Technical Problem
[0009] The present invention is contemplated for providing a copper
alloy sheet material for electrical or electronic parts, such as
connectors, which can simultaneously satisfy high mechanical
strength, high electrical conductivity, and low Young's modulus
that are required of materials for electrical or electronic parts,
such as connectors, along with the development of electronics
industries, and for providing a method of producing the same.
Solution to Problem
[0010] According to the present invention, there is provided the
following means:
(1) A copper alloy sheet material for electrical or electronic
parts, having an alloy composition containing any one or both of Ni
and Co in an amount of 0.5 to 5.0 mass % in total, and Si in an
amount of 0.2 to 1.5 mass %, with the balance being Cu and
inevitable impurities,
[0011] wherein the copper alloy sheet material has a 0.2% proof
stress in the rolling direction of 500 MPa or more, an electrical
conductivity of 30% IACS or more, a Young's modulus of 110 GPa or
less, and a factor of bending deflection of 105 GPa or less.
(2) The copper alloy sheet material for electrical or electronic
parts described in item (1), wherein the copper alloy sheet
material has an area ratio of (1 0 0) plane oriented toward the
rolling direction, which is obtained by analyzing the copper alloy
sheet material with EBSD, is 30% or more. (3) The copper alloy
sheet material for electrical or electronic parts described in item
(1) or (2), wherein the copper alloy sheet material has an area
ratio of (1 1 1) plane oriented toward the rolling direction, which
is obtained by analyzing the copper alloy sheet material with EBSD,
is 15% or less. (4) The copper alloy sheet material for electrical
or electronic parts described in any one of items (1) to (3),
wherein the alloy composition further contains Cr in an amount of
0.05 to 0.5 mass %. (5) The copper alloy sheet material for
electrical or electronic parts described in any one of items (1) to
(4), wherein the alloy composition further contains one, two, or
more selected from the group consisting of Zn, Sn, Mg, Ag, Mn, and
Zr in an amount of 0.01 to 1.0 mass % in total. (6) The copper
alloy sheet material for electrical or electronic parts described
in any one of items (1) to (5), which is a material for connectors.
(7) A connector, which is composed of the copper alloy sheet
material for electrical or electronic parts described in any one of
items (1) to (6). (8) A method of producing the copper alloy sheet
material for electrical or electronic parts described in any one of
items (1) to (7), containing, in this order, the steps of:
subjecting a copper alloy to give the alloy composition to casting;
hot-rolling; cold-rolling 1; intermediate annealing; cold-rolling
2; solution heat treatment; aging heat treatment; finish
cold-rolling; and low-temperature annealing,
[0012] wherein the method of producing further contains, conducting
at least any one or both of the following steps [1] and [2]:
[0013] [1] slowly cooling to 350.degree. C. after the hot-rolling;
and
[0014] [2] carrying out the intermediate annealing and the
cold-rolling 2, repeatedly two times or more.
Advantageous Effects of Invention
[0015] The copper-based alloy material according to the present
invention and the copper alloy material obtained according to the
production method of the present invention each have a low Young's
modulus, without impairing the high mechanical strength or/and the
high electrical conductivity required of materials for electrical
or electronic parts, such as connectors, as compared with
conventional Corson-based alloys, and are favorable as a copper
alloy material for electrical or electronic parts, such as
connectors.
MODE FOR CARRYING OUT THE INVENTION
[0016] Preferable embodiments of the copper alloy sheet material of
the present invention will be described in detail. Herein, the term
"copper alloy material" means a product obtained after a copper
alloy base material is worked into a predetermined shape (for
example, sheet, strip, foil, rod, or wire). Among them, a sheet
material refers to a material which has a specific thickness, is
stable in the shape, and is extended in the plane direction, and in
a broad sense, the sheet material is meant to encompass a strip
material. Herein, with regard to the sheet material, the term
"surface layer of the material (or material surface layer)" means
the "sheet surface layer," and the term "position of a depth of the
material" means the "position in the sheet thickness direction."
There are no particular limitations on the thickness of the sheet
material, but when it is considered that the thickness should well
exhibit the effects of the present invention and should be suitable
for practical applications, the thickness is preferably 8 to 800
.mu.m, and more preferably 50 to 70 .mu.m.
[0017] In the copper alloy sheet material of the present invention,
the characteristics are defined by the accumulation ratio of the
atomic plane in a predetermined direction of a rolled sheet, but
this will be considered enough if the copper alloy sheet material
has such characteristics in the present invention. The shape of the
copper alloy sheet material is not intended to be limited to a
sheet material or a strip material, and it is noted that in the
present invention, a tube material can also be construed and
treated as a sheet material.
[0018] With respect to the copper alloy material of the present
invention (as a representative shape, a sheet material), which is a
precipitate-type copper alloy material, such as Corson-based,
having a low Young's modulus and a low factor of bending
deflection, first, the alloy composition thereof, followed by the
texture thereof, will be described.
(Component Composition of the Copper Alloy Material)
[0019] The reasons for limiting the chemical component composition
in the copper alloy material of the present invention, which are
the premises for attaining high mechanical strength, will be
described (the unit for the content "%" described herein is all in
terms of "mass %").
(Ni: 0.5 to 5.0%)
[0020] Ni is an element that is contained together with Si, which
will be described below, to form a Ni.sub.2Si phase that is
precipitated by an aging treatment, to contribute to enhancement of
the mechanical strength of the resultant copper alloy material. If
the content of Ni is too small, the Ni.sub.2Si phase is
insufficient, and the tensile strength of the copper alloy material
may not be enhanced. On the other hand, if the content of Ni is too
large, the electrical conductivity lowers, and the hot-rolling
workability is deteriorated. Thus, the content of Ni is set to the
range of 0.5 to 5.0%, preferably 1.5 to 4.0%.
(Co: 0.5 to 5.0%)
[0021] Co is an element that is contained together with Si, to form
a Co.sub.2Si phase that is precipitated by the aging treatment, to
contribute to enhancement of the mechanical strength of the
resultant copper alloy material. When it is intended to enhance
electrical conductivity, it is preferable to contain Co alone,
without containing Ni. If the content of Co is too small, the
Co.sub.2Si phase is insufficient, and the tensile strength of the
copper alloy material may not be enhanced. On the other hand, if
the content of Co is too large, the electrical conductivity lowers,
and the hot-rolling workability is deteriorated. Thus, the content
of Co is set to the range of 0.5 to 5.0%, preferably 0.8 to 3.0%,
more preferably 1.1 to 1.7%.
[0022] The copper alloy material may contain both of these Ni and
Co, but their content is set to 0.5 to 5.0% in total. When
containing both of Ni and Co, both Ni.sub.2Si and Co.sub.2Si are
precipitated upon the aging treatment, to enhance the aging
strength. If the total content of Ni and Co is too small, the
tensile strength may not be enhanced, and if the total content is
too large, electrical conductivity and hot-rolling workability are
deteriorated. Thus, the total content of Ni and Co is set in the
range of 0.5 to 5.0%, preferably 0.8 to 4.0%.
(Si)
[0023] Si is contained together with the Ni and/or Co, to form the
Ni.sub.2Si phase and/or Co.sub.2Si phase that are precipitated by
the aging treatment, to contribute to enhancement of the mechanical
strength of the copper alloy material. The content of Si is set to
0.2 to 1.5%, preferably 0.2 to 1.0%. When the content of Si is set
such that the ratio Ni/Si as a stoichiometric ratio is set to 4.2,
and the ratio Co/Si as a stoichiometric ratio is set to 4.2, the
balance between electrical conductivity and mechanical strength is
most favorably achieved. Thus, it is preferable to set the content
of Si such that the ratios Ni/Si, Co/Si, and (Ni+Co)/Si are in the
range of 3.2 to 5.2, more preferably 3.5 to 4.8.
[0024] If Si is excessively contained in an amount outside this
range, the tensile strength of the copper alloy material can be
enhanced, but the excess amount of Si is made into a solid solution
in the matrix of copper, to lower the electrical conductivity of
the copper alloy material. Further, if Si is contained in excess,
the casting property in casting, and/or hot- and cold-rolling
workability are also deteriorated, to result in being apt to
occurring casting cracks or rolling cracks. On the other hand, if
the content of Si is outside this range and too small, the
precipitated phase of Ni.sub.2Si and/or Co.sub.2Si is
insufficiently formed, and the tensile strength of the material may
not be enhanced.
(Cr)
[0025] In addition to the compositions described above, the copper
alloy may also contain Cr in an amount of 0.05 to 0.5 mass %. Cr
has an effect of making grains in the alloy finer, to contribute to
enhancement of the mechanical strength and/or bending property of
the copper alloy material. If the content is too small, the effect
is less, and if the content is too large, crystallized products are
formed upon casting, to lower the aging strength.
(Other Alloying Elements)
[0026] The copper alloy material of the present invention may
optionally contain, as an additive element(s) in addition to the
above-mentioned basic composition, one, two or more of Sn: 0.01 to
1.0%, Zn: 0.01 to 1.0%, Ag: 0.01 to 1.0%, Mn: 0.01 to 1.0%, Zr: 0.1
to 1.0%, and Mg: 0.01 to 1.0%, each in terms of mass %, in a total
amount of 0.01 to 1.0%. These elements are elements, which have a
common action/effect of further enhancing any of high mechanical
strength or electrical conductivity, or low Young's modulus, each
of which is a target to be exhibited by the copper alloy material
of the present invention, and which, in addition to this or instead
of this, further enhance other properties (stress relaxation
resistance, and the like). The characteristic actions/effects and
the significance of the content ranges of the respective elements
will be described below.
(Sn)
[0027] Sn is an element that mainly enhances the mechanical
strength of the resultant copper alloy material, and in the case
where the material is utilized in applications where these
characteristics are regarded as important, Sn is selectively
contained. If the content of Sn is too small, the
strength-enhancing effect is less. On the other hand, when Sn is
contained, the electrical conductivity of the copper alloy material
is generally lowered. In particular, if the content of Sn is too
large, it is difficult to attain the electrical conductivity of the
copper alloy material to be 30% IACS or higher. Thus, when
contained, the content of Sn is generally set to the range of 0.01
to 1.0%.
(Zn)
[0028] By containing Zn, it becomes possible to enhance the
migration resistance or heat resistant peelability upon soldering.
If the content of Zn is too small, the effect is less. On the other
hand, when Zn is contained, the electrical conductivity of the
copper alloy material is generally lowered, and, if the content of
Zn is too large, it is difficult to attain the electrical
conductivity of the copper alloy material to be 30% IACS or higher.
Thus, the content of Zn is generally set to the range of 0.01 to
1.0%.
(Ag)
[0029] Ag contributes to enhancement of the mechanical strength of
the copper alloy material. If the content of Ag is too small, the
effect is less. On the other hand, even if Ag is contained in
excess, the strength-enhancing effect is saturated. Thus, when
contained, the content of Ag is generally set to the range of 0.01
to 1.0%.
(Mn)
[0030] Mn mainly enhances workability in hot-rolling of the alloy.
If the content of Mn is too small, the effect is less. On the other
hand, if the content of Mn is too large, the melt fluidity in
casting of the copper alloy is deteriorated, thereby to lower the
casting yield. Thus, when Mn is contained, the content of Mn is
generally set to the range of 0.01 to 1.0%.
(Zr)
[0031] Zr mainly makes grains finer, to enhance the mechanical
strength and/or bending property of the copper alloy material. If
the content of Zr is too small, the effect is less. On the other
hand, if the content of Zr is too large, compounds are formed, and
the workability in rolling or the like of the copper alloy material
is deteriorated. Thus, when Zr is contained, the content of Zr is
generally set to the range of 0.01 to 1.0%.
(Mg)
[0032] Mg enhances the stress relaxation resistance. Thus, in the
case where stress relaxation resistance is required, Mg is
selectively contained in an amount in the range of 0.01 to 1.0%. If
the content of Mg is too small, the target effect by addition
thereof is less, and if the content is too large, the electrical
conductivity is lowered. Thus, when contained, the content of Mg is
generally set to the range of 0.01 to 1.0%.
[0033] Mg, Sn, and Zn each improve the stress relaxation
resistance, when added to Cu--Ni--Si-based, Cu--Ni--Co--Si-based,
and Cu--Co--Si-based copper alloys. When these elements are added
together, as compared with the case where any one of them is added
solely, the stress relaxation resistance is further improved by
synergistic effects. Further, an effect of remarkably improving
solder brittleness is obtained.
[0034] The electrical conductivity that is realized by the copper
alloy sheet material of the present invention is 30% IACS or more,
preferably in the range of 35% IACS or more, and more preferably in
the range of 45% IACS or more. There are no particular limitations
on the upper limit, but the upper limit is practically 60% IACS or
less.
[0035] Furthermore, a preferred range of the 0.2% proof stress in
the rolling direction that is realized by the copper alloy material
of the present invention is 500 MPa or more, more preferably 650
MPa or more, and further preferably in the range of 800 MPa or
more. There are no particular limitations on the upper limit, but
the upper limit is practically 1,100 MPa or less.
[0036] The factor of bending deflection is preferably 105 GPa or
less, and more preferably 100 GPa or less. There are no particular
limitations on the lower limit, but the lower limit is practically
60 GPa or more.
[0037] The Young's modulus is 110 GPa or less, and more preferably
100 GPa or less. There are no particular limitations on the lower
limit, but the lower limit is practically 70 GPa or more.
(Crystal Structure)
[0038] With respect to the crystal structure of the copper alloy
material of the present invention, in particular, in order to
realize a low Young's modulus and a low factor of bending
deflection, it is preferable to have a crystal structure in which
the area ratio of (1 0 0) plane oriented toward the rolling
direction (RD) is 30% or more, in the results of analysis from the
RD according to the SEM-EBSD method. Herein, all grains having an
orientation in which the angle formed by the rolling direction (RD)
of the sheet material and the normal direction of the relevant
plane is 10.degree. or less, are defined to have the (1 0 0) plane
that is oriented toward the RD.
[0039] In the case of a copper alloy sheet material, the material
mainly forms crystal textures called cube orientation, Goss
orientation, brass orientation, copper orientation, S orientation,
and the like, which will be described below, and has crystal faces
corresponding to those orientations, respectively.
[0040] The formation of these crystal textures occurs differently,
even in the case of the same crystal system, depending on the
differences in the methods of working and heat treatment. The
method of indicating the crystal orientation in the present
specification is such that a Cartesian coordinate system is
employed, representing the rolling direction (RD) of the material
in the X-axis, the transverse direction (TD) in the Y-axis, and the
direction (ND) normal to the rolling direction in the Z-axis,
various regions in the material are indicated in the form of (h k
l) [u v w], using the index (h k l) of the crystal plane that is
perpendicular to the Z-axis (i.e. parallel to the rolling
direction) and the index [u v w] in the crystal direction parallel
to the X-axis (i.e. perpendicular to the rolling direction).
Further, the orientation that is equivalent based on the symmetry
of the cubic crystal of a copper alloy is indicated as {h k l}<u
v w>, using parenthesis symbols representing families, such as
in (1 3 2) [6 -4 3], and (2 3 1) [3 -4 6]. In accordance with the
expressions as described above, the respective orientations are
expressed as follows.
[0041] As representative crystal orientations that are exhibited by
a FCC metal, components expressed by the following indices are
general.
TABLE-US-00001 Cube orientation {0 0 1} <1 0 0> Rotated-cube
orientation {0 1 2} <1 0 0> Goss orientation {0 1 1} <1 0
0> Rotated-Goss orientation {0 1 1} <0 1 1> Brass
orientation {0 1 1} <2 1 1> Copper orientation {1 1 2} <1
1 1> S orientation {1 2 3} <6 3 4> P orientation {0 1 1}
<1 1 1>
[0042] In the crystal structures of a conventional copper alloy
material sheet, when the constituent proportions of these crystal
faces change, the elastic behavior of the sheet material
changes.
[0043] It is known that copper alloys exhibit orientations such as
described above, however, as we have keenly studied, we found that
it is effective to increase the area ratio of the (1 0 0) plane
that is oriented toward the RD in decreasing the Young's modulus
and the factor of bending deflection. Examples of the orientation
component in which the (1 0 0) plane is oriented toward the RD
include the aforementioned cube orientation, Rotated-cube
orientation, Goss orientation, and the like. With respect to the
crystal texture of a conventional Corson-based high strength copper
alloy sheet, the inventors of the present invention confirmed that
when the copper alloy sheet is produced according to a conventional
method, the S orientation {1 2 3}<6 3 4> or/and the brass
orientation {0 1 1}<2 1 1>, other than the cube orientation
{0 0 1}<1 0 0>, constitutes the main component, and the
proportion of the cube orientation is lowered, while the Young's
modulus and the factor of bending deflection become high. In
particular, we confirmed that in the case where there are many (1 1
1) planes in the RD direction, the Young's modulus and the factor
of bending deflection become higher.
[0044] Thus, for the crystal texture of the copper alloy sheet of
the present invention, it is preferable that, among the crystal
faces oriented toward the RD, the area ratio of crystal faces in
which the angle formed by the two vectors of the plane orientation
{for example, the normal direction of the (1 0 0) plane} and the
RD, is 10.degree. or less, be 30% or more, thereby to allow a
crystal texture having a low Young's modulus and a low factor of
bending deflection. The area ratio of the (1 0 0) plane oriented
toward the RD is more preferably 40% or more, and even more
preferably 50% or more. When the area ratio of the (1 0 0) plane
that is oriented toward the RD is increased as such, the Young's
modulus can be set to 110 GPa or less, and the factor of bending
deflection can be set to 105 GPa or less. This is because the area
ratio of the crystal face of (1 0 0) oriented toward the RD, which
is low in the Young's modulus and factor of bending deflection,
increases. Furthermore, as the area ratio of the crystal face of (1
1 1) oriented toward the RD, which is high in the Young's modulus
and factor of bending deflection, decreases, the Young's modulus
can be lowered. The area ratio of the (1 1 1) plane oriented toward
the RD is preferably 15% or less, and more preferably 10% or
less.
[0045] In the crystal texture of the copper alloy sheet, the
measurement of the area ratio of the (1 0 0) plane oriented toward
the RD is carried out by analyzing the electron-microscopic texture
by SEM with EBSD. Herein, a range containing 400 or more grains
(on, for example, in a sample area which measures 800 .mu.m on each
of the four sides) is scanned in a stepwise manner at an interval
of 1 .mu.m, to analyze the orientation. Since the distribution of
these orientations varies along the sheet thickness direction, it
is preferable to determine the area ratio by taking some arbitrary
points in the sheet thickness direction, to determine the
orientation distribution by taking an average of the data thus
obtained.
[0046] This SEM-EBSD method is an abbreviation of the Scanning
Electron Microscopy-Electron Back Scattered Diffraction Pattern
method. That is, the method involves, irradiating individual grains
described in a scanning electron microscope (SEM) image with an
electron beam, and identifying the individual crystal orientations
from the diffracted electrons.
[0047] The method of indicating the crystal orientation in the
present specification is such that a Cartesian coordinate system is
employed, representing the rolling direction (RD) of the material
in the X-axis, the transverse direction (TD) in the Y-axis, and the
direction (ND) normal to the rolling direction in the Z-axis, and
the proportion of regions in which the (1 0 0) plane is oriented
toward the RD is defined as the area ratio thereof. The angle
formed by the two vectors of the normal direction of the (1 0 0)
plane of each grain within the measured region and the RD is
calculated, and the sum of the area is calculated for the regions
having atomic planes in which this angle is 10.degree. or less. A
value obtained by dividing this sum by the total measured area is
defined as the area ratio (%) of regions having atomic planes in
which the angle formed by the normal direction of the (1 0 0) plane
and the RD is 10.degree. or less.
[0048] That is, in the present invention, in connection with the
accumulation of those atomic planes oriented toward the rolling
direction (RD) of the rolled sheet, the region having atomic planes
in which the angle formed by the normal direction of the (1 0 0)
plane and the RD is 10.degree. or less, represents a region having
planes oriented toward the rolling direction (RD) of the rolled
sheet, that is, in connection with the accumulation of atomic
planes facing to the RD, a region combining the (1 0 0) plane
itself which adopts the rolling direction (RD) of the rolled sheet
as the normal direction, which is an ideal orientation, with the
atomic planes in which the angle formed by the normal direction of
the (1 0 0) plane and the RD is 10.degree. or less (i.e. the sum of
areas of these planes). Hereinafter, these planes are collectively
referred to as the (1 0 0) plane oriented toward the RD, and these
regions are simply referred to as a region of atomic planes in
which the (1 0 0) plane is oriented toward the RD. Furthermore, the
same also applies to the (1 1 1) plane oriented toward the RD.
[0049] When conducting the EBSD analysis, in order to obtain a
clear Kikuchi-line diffraction image, it is preferable that the
analysis is conducted, after mirror polishing of the substrate
surface, with polishing particles of colloidal silica, after
mechanical polishing. Further, unless otherwise specified, the
measurement is carried out from the ND direction of the sheet
surface.
[0050] Herein, the features of the EBSD analysis will be explained
in comparison with the X-ray diffraction analysis. First, the first
feature is that there are crystal orientations that cannot be
measured by the X-ray diffraction analysis, and they are the
S-orientation and the BR orientation. In other words, by employing
EBSD, for the first time, information on the S-orientation and the
BR-orientation are obtained, and the relationship between the metal
texture to be specified by the orientations and the actions/effects
thereof is elucidated. The second feature is that X-ray diffraction
analyzes the quantity of the crystal orientation that is included
in the range of about .+-.0.5.degree. with respect to ND//{h k l},
while EBSD analyzes the quantity of the crystal orientation that is
included in the range of .+-.10.degree. with respect to the
relevant orientation. Therefore, when an EBSD analysis is
conducted, a huge range of comprehensive information on the metal
texture is obtained, and those states that cannot be easily
specified by X-ray diffraction in the overall alloy material can be
clarified. As explained above, the information obtainable by an
EBSD analysis and the information obtainable by an X-ray
diffraction analysis are different from each other in the contents
and the natures. Unless otherwise specified, in the present
specification, the results of EBSD are results obtained in
connection with the ND direction of a copper alloy sheet
material.
(Production Conditions)
[0051] Next, some preferable production conditions for the copper
alloy material of the present invention will be described below.
The copper alloy material of the present invention is produced, for
example, through the steps of: casting, hot-rolling, slow-cooling,
cold-rolling 1, intermediate annealing, cold-rolling 2, solution
heat treatment, aging heat treatment, finish cold-rolling, and
low-temperature annealing. The copper alloy material of the present
invention can be produced, with facilities almost similar to those
conventional ones for Corson-based alloy. In order to obtain
predetermined properties as well as a predetermined crystal
texture, it is necessary to appropriately control the production
conditions in the steps. In this regard, the copper alloy material
of the present invention can be produced, by carrying out, under
the given conditions, at least any of treatments and/or workings
selected from, the treatments and/or workings after the
hot-rolling, and the cold-rolling and intermediate annealing before
the solution treatment.
[0052] The casting is carried out to a molten copper alloy having
its components set to any of the composition ranges described
above, to cast into an ingot. Then, the resultant ingot is
face-milled, followed by subjecting to heating or a homogenization
heat treatment at 800 to 1,000.degree. C., and then hot-rolling.
Herein, in the conventional methods of producing Corson-based
alloys, the alloy is quenched immediately after the hot-rolling, by
water-quenching or the like. On the other hand, a preferable first
embodiment of the method of producing the copper alloy material of
the present invention is characterized in that the copper alloy
material is not subjected to quenching but is subjected to
slow-cooling, to increase the (1 0 0) plane oriented toward the RD
after the hot-rolling. The cooling speed in the slow-cooling is
preferably 5 K/second or less. The orientation in which the (1 0 0)
plane is oriented toward the RD causes a restoration phenomenon at
a lower temperature, as compared with other orientations, and thus
the area ratio of the orientation in which the (1 0 0) plane is
oriented toward the RD, in the hot-rolled texture, can be
increased. When the proportion of grains having the orientation in
which the (1 0 0) plane is oriented toward the RD, in this
hot-rolled texture is increased, the area ratio of the orientation
in which the (1 0 0) plane is oriented toward the RD can be
increased, in the solution step which is a following step. Since no
change occurs in the texture when the temperature at the cooling is
lower than 350.degree. C., once the temperature has been
cooled-down to below 350.degree. C., the material may be quenched
by water-quenching or the like, to shorten the production time
period.
[0053] Next, after the completion of the hot-rolling and cooling,
the resultant surface is face milled, followed by the cold-rolling
1. If the rolling ratio of this cold-rolling 1 is too low, even if
the material is thereafter subjected to the production to final
products, the brass orientation, the S orientation, or the like
develops, and it becomes difficult to increase the area ratio of
the (1 0 0) plane. For that reason, the rolling ratio of the
cold-rolling 1 is preferably 70% or higher.
[0054] After the cold-rolling 1, the intermediate annealing is
carried out at 300 to 800.degree. C. for 5 seconds to 2 hours.
After the intermediate annealing, the cold-rolling 2 is carried out
at a rolling ratio of 3 to 60%. When these intermediate annealing
and cold-rolling 2 are repeatedly carried out, the area ratio of
the (1 0 0) plane oriented toward the RD can be further increased.
Thus, according to a preferable second embodiment of the method of
producing the copper alloy material of the present invention, the
steps of the intermediate annealing and cold-rolling 2 are
repeatedly carried out two times or more.
[0055] The solution treatment is carried out under the conditions
at 600 to 1,000.degree. C. for 5 seconds to 300 seconds. Since the
necessary temperature conditions vary depending on the
concentration of Ni and/or Co, it is necessary to select
appropriate temperature conditions according to the Ni and/or Co
concentrations. If the solution temperature is too low, the
mechanical strength is insufficient upon the aging treatment. If
the solution temperature is too high, the material is softened more
than necessary, and it becomes difficult to control the shape,
which is not preferable.
[0056] The aging treatment is carried out in the range of at 400 to
600.degree. C. for 0.5 hours to 8 hours. Since the necessary
temperature conditions vary depending on the concentration of Ni
and/or Co, it is necessary to select appropriate temperature
conditions according to the Ni and/or Co concentrations. If the
temperature of the aging treatment is too low, the amount of aged
precipitate is decreased, to result in the insufficient mechanical
strength. Furthermore, if the temperature of the aging treatment is
too high, the precipitate is coarsened, to result in lowering of
the mechanical strength.
[0057] It is preferable to set the working ratio of the finish
cold-rolling after the solution treatment, to 50% or less. When the
working ratio is appropriately controlled as such, the grains
having the (1 0 0) orientation, such as the cube orientation, are
suppressed from undergoing orientation rotation to the brass
orientation, the copper orientation, or the like. Thus, the
resultant copper alloy material is excellent in the physical
properties, and a preferred state of the crystal texture can be
achieved.
[0058] The low-temperature annealing is carried out under the
conditions at 300 to 700.degree. C. for 10 seconds to 2 hours.
Through this annealing, the stress relaxation resistance and the
spring deflection limit, which are required of connector materials,
can be enhanced.
[0059] In a more preferred production method of obtaining the
copper alloy material of the present invention, the steps of both
the first embodiment and the second embodiment are carried out,
that is, after the hot-rolling, until the temperature reaches at
least a temperature range of lower than 350.degree. C., not
quenching but slow-cooling (preferably, at a cooling speed of 5
K/sec or less) is carried out, and the steps of the intermediate
annealing and cold-rolling 2 are carried out repeatedly two times
or more.
TABLE-US-00002 TABLE A Step (1) Step (2) Slow- Final Aging
Homogeni- cooling solution precipitation zation Hot- after hot-
Face- Cold- Intermediate Cold- heat heat Cold- Temper treatment
rolling rolling milling rolling 1 annealing rolling 2 treatment
treatment rolling annealing Temperature 800 to .smallcircle.
.smallcircle. .smallcircle. -- 300 to -- 600 to 400 to -- 300 to
.degree. C. 1,000 800 1,000 600 700 Working ratio -- -- -- --
.gtoreq.70 -- 3 to -- -- .ltoreq.50 -- % 60 Time period * -- -- --
-- -- 5 s to -- 5 s to 0.5 h to -- 10 s to 2 h 30 s 8 h 2 h * s:
sec., m: min., and h: hour
[0060] In order to ensure that the copper alloy material of the
present invention produced by the method described above has
predetermined characteristics, it is enough to verify through an
EBSD analysis, whether the properties as well as the crystal
texture of the copper alloy material are within the predetermined
ranges.
EXAMPLES
[0061] The present invention will be described in more detail based
on examples given below, but the invention is not meant to be
limited by these.
[0062] Copper alloy sheets were produced, by casting copper alloys
having the respective compositions shown in the following Tables 1
and 2, to evaluate various characteristics, such as mechanical
strength (0.2% proof stress), electrical conductivity, Young's
modulus, and the like.
[0063] First, casting was conducted by a DC (direct chill) method,
to obtain ingots with thickness 30 mm, width 100 mm, and length 150
mm. Then, these ingots were heated to 950.degree. C., followed by
maintaining at this temperature for one hour, hot-rolling to
thickness 14 mm, and slow-cooling at a cooling speed of 1 K/s, and
when the temperature dropped to 300.degree. C. or lower, the
thus-rolled materials were cooled in water. Then, the respective
surface of each of the thus-rolled sheets were face-milled
respectively by 2 mm to remove oxide layer, followed by subjecting
to cold-rolling 1 at a rolling ratio of 90 to 95%. Then, an
intermediate annealing at 350 to 700.degree. C. for 30 minutes was
carried out, followed by cold-rolling 2 at a cold-rolling ratio of
10 to 30%. Then, solution treatment was carried out under any of
conditions of 700 to 950.degree. C. for 5 seconds to 10 minutes,
immediately followed by cooling at a cooling speed of 15.degree.
C./sec or higher. Then, an aging treatment at 400 to 600.degree. C.
for 2 hours was conducted, under an inert gas atmosphere, followed
by finish rolling at a rolling ratio of 50% or less. Thus, the
final sheet thickness was set to 0.15 mm. After the finish rolling,
the materials were subjected to low-temperature annealing at
400.degree. C. for 30 seconds, thereby to obtain copper alloy sheet
materials with various alloying compositions.
[0064] With respect to the thus-produced copper alloy sheets, in
each test examples, samples cut out from the copper alloy sheets
that have been subjected to the low-temperature annealing were
utilized, to conduct the tests and evaluations described below.
(1) Area Ratios of Grains of Crystal Orientations
[0065] The area ratio of the (1 0 0) plane oriented toward the RD
was determined, with respect to the texture of each of the copper
alloy sheet samples.
[0066] That is, grains having a crystal orientation in which the
angle formed by the normal direction of the (1 0 0) plane and the
RD was 10.degree. or less, when analyzed by EBSD from the RD
direction, were designated as grains having the (1 0 0) plane
oriented toward the RD. The area ratio of the (1 0 0) plane
oriented toward the RD was specifically determined as follows.
Measurement was carried out by an EBSD method in a sample measured
region which measured about 800 .mu.m on each of the four sides,
under the conditions of a scan step of 1 .mu.m. The measured area
was adjusted by taking an area containing 400 or more grains as a
reference. As described above, with respect to the (1 0 0) plane of
grains having a normal direction of the (1 0 0) plane which formed
an angle of 10.degree. or less with the rolling direction (RD) of
the sheet material sample, the sum of the areas was determined, and
the sum of the areas was divided by the total measured area, to
obtain the area ratio (%) of the (1 0 0) plane oriented toward the
RD. Herein, those grains in which the angle formed as described
above was 10.degree. or less are defined as grains having the same
orientation.
[0067] Furthermore, the area ratio (%) of the (1 1 1) plane
oriented toward the RD was also determined in the same manner.
(2) 0.2% Proof Stress
[0068] The 0.2% proof stress was determined, with a No. 5 test
piece as stipulated in JIS Z 2201 cut out from the respective
sample, according to JIS Z 2241. The 0.2% proof stress is shown by
an integer round up by multiple of 5 MPa.
(3) Electrical Conductivity
[0069] The electrical conductivity was determined according to JIS
H 0505.
(4) Young's Modulus
[0070] With respect to Young's modulus, the Young's modulus in a
mechanical strength region of the 0.2 proof stress or less was
measured, with a tensile tester, by using a strip-like test piece
with width 20 to 30 mm, with a strain gauge. The test pieces were
cut out in parallel to the rolling direction.
(5) Factor of Bending Deflection
[0071] The factor of bending deflection was measured, according to
the Japan Copper and Brass Association (JCBA) Technical Standard.
The width of the test piece was set to 10 mm, and the length was
set to 15 mm. A bending test of a cantilever beam was carried out,
and the factor of bending deflection was measured, from the load
and the deflection displacement.
[0072] These results are shown in Tables 1 and 2.
TABLE-US-00003 TABLE 1 Area ratio Area ratio (%) of (100) (%) of
(111) Other plane toward plane toward No. Ni Co Si Cr elements RD
RD Ex 1 1.5 0.36 Mg: 0.1 51 10 Ex 2 2.3 0.55 55 7 Ex 3 2.3 0.55 0.3
57 10 Ex 4 2.3 0.55 0.1 50 12 Ex 5 2.3 0.55 0.1 Mg: 0.1, 52 9 Sn:
0.1, Zn: 0.5 Ex 6 2.3 0.55 Ag: 0.1 57 11 Ex 7 2.3 0.55 Mn: 0.1 50
14 Ex 8 2.3 0.55 Zr: 0.1 52 9 Ex 9 3.8 0.90 0.1 53 5 Ex 10 3.8 0.90
0.1 Mg: 0.1, 55 6 Sn: 0.1, Zn: 0.5 Ex 11 3.8 0.90 Sn: 0.1 56 11 Ex
12 3.8 0.90 0.2 45 13 Ex 13 4.9 1.17 Mg: 0.1 58 5 Ex 14 4.9 1.17 56
7 Ex 15 4.9 1.17 Mg: 0.1, 54 13 Sn: 0.1, Zn: 0.5 Ex 16 1.2 1.2 0.57
Mg: 0.1 52 9 Ex 17 1.3 0.8 0.50 Mg: 0.1, 54 8 Sn: 0.1, Zn: 0.5 Ex
18 1.3 0.8 0.50 51 6 Ex 19 2.1 0.7 0.67 0.1 50 10 Ex 20 2.4 1.2
0.86 51 8 Ex 21 0.8 2.6 0.81 52 4 Ex 22 0.6 2.8 0.81 51 10 Ex 23
0.8 0.19 Mg: 0.1 54 13 Ex 24 1.4 0.33 Mg: 0.1 50 10 Ex 25 2.3 0.55
48 8 Ex 26 3.1 0.74 Mg: 0.1, 42 14 Sn: 0.1, Zn: 0.5 Ex 27 3.6 0.86
Ag: 0.1 50 10 Ex 28 1.2 1.2 0.75 Mg: 0.1 52 10 Ex 29 1.2 1.2 0.46
Mg: 0.1 52 10 Factor of Electrical 0.2% proof Young's bending
conductivity stress modulus deflection No. (% IACS) (MPa) (GPa)
(GPa) Ex 1 44 710 104 94 Ex 2 42 820 103 93 Ex 3 41 840 102 92 Ex 4
42 830 107 97 Ex 5 39 840 105 94 Ex 6 43 820 102 92 Ex 7 40 830 109
100 Ex 8 40 830 108 98 Ex 9 38 870 107 97 Ex 10 36 880 106 96 Ex 11
37 920 104 95 Ex 12 35 940 110 101 Ex 13 33 905 103 93 Ex 14 34 930
106 96 Ex 15 31 1,000 110 100 Ex 16 50 840 107 97 Ex 17 51 830 105
96 Ex 18 50 810 108 97 Ex 19 47 820 108 98 Ex 20 42 840 108 97 Ex
21 41 820 108 98 Ex 22 62 830 107 97 Ex 23 60 620 104 94 Ex 24 55
720 108 97 Ex 25 55 800 109 98 Ex 26 45 810 109 99 Ex 27 55 830 106
95 Ex 28 42 850 109 98 Ex 29 55 830 106 96 Unit of content: mass %
"Ex" means Example according to this invention.
TABLE-US-00004 TABLE 2 Area ratio Area ratio (%) of (100) (%) of
(111) Other plane toward plane toward Ni Co Si Cr elements RD RD C
Ex 1 0.4 0.10 50 9 C Ex 2 0.2 0.2 0.10 0.1 Mg: 0.1, 52 10 Sn: 0.1,
Zn: 0.5 C Ex 3 5.3 1.26 Production was stopped, due to cracks
occurred in hot-working. C Ex 4 2.2 3.5 1.36 Production was
stopped, due to cracks occurred in hot-working. C Ex 5 0.3 0.07 0.2
Mg: 0.1 54 13 C Ex 6 5.3 1.26 Production was stopped, due to cracks
occurred in hot-working. C Ex 7 5.8 1.38 Production was stopped,
due to cracks occurred in hot-working. C Ex 8 2.3 1.68 50 11 C Ex
2-2 2.3 0.55 1 18 C Ex 2-3 2.3 0.55 29 8 Factor of Electrical 0.2%
proof Young's bending conductivity stress modulus deflection (%
IACS) (MPa) (GPa) (GPa) C Ex 1 68 470 109 99 C Ex 2 66 490 108 98 C
Ex 3 Production was stopped, due to cracks occurred in hot-working.
C Ex 4 Production was stopped, due to cracks occurred in
hot-working. C Ex 5 70 480 107 97 C Ex 6 Production was stopped,
due to cracks occurred in hot-working. C Ex 7 Production was
stopped, due to cracks occurred in hot-working. C Ex 8 18 740 110
100 C Ex 2-2 40 740 132 121 C Ex 2-3 40 740 124 115 Unit of
content: mass % "C Ex" means Comparative Example.
[0073] Table 1 shows the examples according to the present
invention. Examples 1 to 29 each had the crystal textures fallen
within the preferred range according to the present invention, and
each were excellent in the 0.2% proof stress, electrical
conductivity, Young's modulus, and factor of bending
deflection.
[0074] Table 2 shows Comparative examples against the present
invention. Comparative Examples 1, 2, and 5 were too small in the
contents of Ni and/or Co and the content of Si, as compared with
the ranges as defined by the present invention, and was poor in the
0.2% proof stress. Comparative Examples 3, 4, 6, and 7 were too
large in the contents of Ni and/or Co, and cracks occurred in the
hot-rolling, to stop the production. Comparative Example 8 was too
high in the content of Si, and was poor in the electrical
conductivity.
[0075] The following comparative examples are test examples of
using the same ingot as that in Example 2. [0076] Comparative
Example 2-2 is a test example produced in the same manner as in
Example 2, except that water-quenching was carried out immediately
after the hot-rolling, and no steps of the intermediate annealing
and cold-rolling 2 were conducted. However, the area ratio of the
(1 0 0) plane oriented toward the RD was conspicuously low, the
area ratio of the (1 1 1) plane was conspicuously high, and the
Young's modulus and the factor of bending deflection were
conspicuously higher than those of the examples according to the
present invention. [0077] Comparative Example 2-3 is a test example
produced in the same manner as in Example 2, except that
water-quenching was carried out immediately after the hot-rolling.
However, the area ratio of the (1 0 0) plane oriented toward the RD
was conspicuously low, and the Young's modulus was conspicuously
higher than that of the examples according to the present
invention.
TABLE-US-00005 [0077] TABLE B Step (1) Homogeni- Slow-cooling
Solution Step (2) zation Hot- after hot- Face- Cold- Intermediate
Cold- heat Cold- Low-temp treatment rolling rolling milling rolling
1 annealing rolling 2 treatment Aging rolling annealing Ex
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .ltoreq.50% .smallcircle. C Ex 2-2 .smallcircle.
.smallcircle. -- * .smallcircle. .smallcircle. -- -- .smallcircle.
.smallcircle. .ltoreq.50% .smallcircle. C Ex 2-3 .smallcircle.
.smallcircle. -- * .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .ltoreq.50% .smallcircle.
* Water-quenching was conducted immediately after the hot-rolling.
"Ex" means Example according to this invention, and "C Ex" means
Comparative Example.
[0078] Other examples according to the present invention are shown
in Table 3.
TABLE-US-00006 TABLE 3 Area ratio Area ratio (%) of (100) (%) of
(111) Other plane toward plane toward Ni Co Si Cr elements RD RD Ex
10-2 3.8 0.90 0.1 Mg: 0.1, 47 11 Sn: 0.1, Zn: 0.5 Ex 10-3 3.8 0.90
0.1 Mg: 0.1, 82 4 Sn: 0.1, Zn: 0.5 Ex 18-2 1.3 0.8 0.50 46 9 Ex
18-3 1.3 0.8 0.50 69 7 Ex 25-2 2.3 0.55 43 10 Ex 25-3 2.3 0.55 78 3
Electrical 0.2% proof Young's Factor of bending conductivity stress
modulus deflection (% IACS) (MPa) (GPa) (GPa) Ex 10-2 38 880 109 99
Ex 10-3 38 890 78 70 Ex 18-2 50 835 108 99 Ex 18-3 50 840 94 83 Ex
25-2 42 860 108 98 Ex 25-3 42 860 84 75 Unit of content: mass %
"Ex" means Example according to this invention.
[0079] Examples 10-2, 18-2, and 25-2 of Table 3 are test examples
that were produced in the same manner as in the respective examples
of Table 1, except that the same ingots as those in Examples 10,
18, and 25 of Table 1 were respectively used, the materials were
water-quenched immediately after the hot-rolling, and the
intermediate annealing and the cold-rolling 2 were carried out
repeatedly two times, and had their characteristics evaluated in
the same manner as above. These examples had the area ratios of the
(1 0 0) plane oriented toward the RD within the preferred range
according to the present invention, and were excellent in the
mechanical strength, electrical conductivity, Young's modulus, and
factor of bending deflection.
[0080] Examples 10-3, 18-3, and 25-3 are test examples that were
produced in the same manner as in the respective examples of Table
1, except that the same ingots as those in Examples 10, 18, and 25
of Table 1 were respectively used, and the intermediate annealing
and the cold-rolling 2 were carried out repeatedly two times, and
had their characteristics evaluated in the same manner as above.
These examples had the particularly high area ratios of the (1 0 0)
plane oriented toward the RD, and had the particularly low Young's
moduli such as 100 GPa or less, and the particularly low factor of
bending deflections such as 90 GPa, and were excellent in the 0.2%
proof stress and electrical conductivity.
[0081] Next, in order to clarify the difference between copper
alloy sheet materials produced under the conventional production
conditions and the copper alloy sheet material according to the
present invention, copper alloy sheet materials were produced under
the conventional conditions, and evaluations of the same
characteristic items as described above were conducted. The working
ratio was adjusted so that, unless otherwise specified, the
thickness of the respective sheet material would be the same as the
thickness in the examples described above.
Comparative Example 101
Conditions Described in JP-A-2009-007666
[0082] An alloy formed by blending the same metal elements as those
in Example 1-1, with the balance of Cu and inevitable impurities,
was melted in a high-frequency melting furnace, followed by casting
at a cooling speed of 0.1 to 100.degree. C./sec, to obtain an
ingot. The resultant ingot was maintained at 900 to 1,020.degree.
C. for 3 minutes to 10 hours, followed by subjecting to hot
working, quenching in water, and then surface milling to remove
oxide scale. For the subsequent steps, use was made of the
treatments/workings of the following steps A-3 and B-3, to produce
a copper alloy c01.
[0083] The production steps included one, two times or more
solution heat treatments. Herein, the steps were divided into those
before and after the final solution heat treatment, so that the
steps up to the intermediate solution treatment are designated as
Step A-3, while the steps after the intermediate solution treatment
are designated as Step B-3.
[0084] Step A-3: Cold working at a cross-sectional area reduction
ratio of 20% or greater, a heat treatment at 350 to 750.degree. C.
for 5 minutes to 10 hours, cold working at a cross-sectional area
reduction ratio of 5 to 50%, and a solution heat treatment at 800
to 1,000.degree. C. for 5 seconds to 30 minutes.
[0085] Step B-3: Cold working at a cross-sectional area reduction
ratio of 50% or less, a heat treatment at 400 to 700.degree. C. for
5 minutes to 10 hours, cold working at a cross-sectional area
reduction ratio of 30% or less, and temper annealing at 200 to
550.degree. C. for 5 seconds to 10 hours.
[0086] The test specimen c01 thus obtained was different from those
in the examples according to this invention, in terms of the
slow-cooling down to 350.degree. C. after the hot-rolling, whether
conducted or not conducted, in connection with the production
conditions, and resulted in a conspicuously high area ratio of the
(1 1 1) plane oriented toward the RD, and not satisfying the
requirements on the Young's modulus and the factor of bending
deflection.
Comparative Example 102
Conditions Described in JP-A-2006-283059
[0087] A copper alloy having the same composition as in Example 1-1
according to this invention was melted in the air under charcoal
coating with an electric furnace, to judge whether the copper alloy
was able to be cast or not. The resultant ingot produced by melting
was hot rolled, to finish to thickness 15 mm. Then, this hot-rolled
sheet was subjected to cold-rollings and heat treatments
(cold-rolling 1.fwdarw.solution continuous
annealing.fwdarw.cold-rolling 2.fwdarw.aging.fwdarw.cold-rolling
3.fwdarw.short-time annealing), to produce a copper alloy sheet
(c02) with a predetermined thickness.
[0088] The test specimen c02 thus obtained was different from that
in Example 1 according to this invention, in terms of the
slow-cooling down to 350.degree. C. after the hot-rolling, whether
conducted or not conducted, and the intermediate annealing and
cold-rolling before the solution treatment, whether conducted or
not conducted, in connection with the production conditions, and
resulted in a conspicuously high area ratio of the (1 1 1) plane
oriented toward the RD, and not satisfying the requirements on the
Young's modulus and the factor of bending deflection.
Comparative Example 103
Conditions Described in JP-A-2006-152392
[0089] An alloy having the same composition as in Example 1-1
according to this invention was melted in the air under charcoal
coating in a kryptol furnace, followed by casting in a book mold
made of cast iron, to produce an ingot with a size of thickness 50
mm, width 75 mm, and length 180 mm. Then, the surface of the ingot
was surface milled, followed by hot rolling at a temperature of
950.degree. C. until that the thickness became 15 mm, and then
quenching in water from a temperature of 750.degree. C. or higher.
Then, oxide scale was removed, followed by cold-rolling, to give a
sheet with a predetermined thickness.
[0090] Then, the resultant sheet was subjected to a solution
treatment by heating at the temperature for 20 seconds, in a salt
bath furnace, followed by quenching in water, and then finish
cold-rolling of the second half, to produce a cold-rolled sheet
with any of various thicknesses. At that time, as shown below,
cold-rolled sheets (c03) were obtained by changing the working
ratio (%) in these cold-rollings. These cold-rolled sheets were
subjected to aging by changing the temperature (.degree. C.) and
the time period (hr) as shown below.
[0091] Cold-working ratio: 95%
[0092] Solution treatment temperature: 900.degree. C.
[0093] Artificial age-hardening temperature.times.time period:
450.degree. C..times.4 hours
[0094] Sheet thickness: 0.6 mm
[0095] The test specimen c03 thus obtained was different from that
in Example 1 according to this invention, in terms of the
slow-cooling down to 350.degree. C. after the hot-rolling, whether
conducted or not conducted, and the intermediate annealing and
cold-rolling before the solution treatment, whether conducted or
not conducted, in connection with the production conditions, and
resulted in a conspicuously high area ratio of the (1 1 1) plane
oriented toward the RD, and not satisfying the requirements on the
Young's modulus and the factor of bending deflection.
Comparative Example 104
Conditions Described in JP-A-2008-223136
[0096] The copper alloy shown in Example 1 was melted, followed by
casting with a vertical continuous casting machine. From the
thus-obtained ingot (thickness 180 mm), a sample with thickness 50
mm was cut out, and this sample was heated to 950.degree. C.,
followed by extracting, and then starting hot-rolling. At that
time, the pass schedule was set to the rolling ratio in the
temperature range of 950 to 700.degree. C. to be 60% or higher, and
to conduct rolling even in the temperature range of lower than
700.degree. C. The final pass temperature of hot-rolling was
between 600.degree. C. and 400.degree. C. The total hot-rolling
ratio from the ingot was about 90%. After the hot-rolling, the
oxide layer at the surface layer was removed by mechanical
polishing (surface milling).
[0097] Then, after conducting cold-rolling, the sample was
subjected to a solution treatment. The temperature change at the
time of the solution treatment was monitored with a thermocouple
attached to the sample surface, and the time period for temperature
rise from 100.degree. C. to 700.degree. C. in the course of
temperature rising was determined. The end-point temperature was
adjusted in the range of 700 to 850.degree. C., depending on the
alloy composition, so that the average grain size (a twin boundary
was not regarded as the grain boundary) after the solution
treatment would be 10 to 60 .mu.m, and the retention time period in
the temperature range of 700 to 850.degree. C. was adjusted in the
range of 10 sec to 10 min. Then, the sheet material obtained after
the solution treatment was subjected to intermediate cold-rolling
at the rolling ratio, followed by aging. The aging temperature was
set to a material temperature of 450.degree. C., and the aging time
period was adjusted to the time period at which the hardness
reached the maximum upon the aging at 450.degree. C., depending on
the alloy composition. The optimum solution treatment conditions
and the optimum aging time period had been found by preliminary
experiments in accordance with the alloy composition. Then, finish
cold-rolling was conducted at the rolling ratio. Samples that had
been subjected to the finish cold-rolling were then further
subjected to low-temperature annealing of placing the sample in a
furnace at 400.degree. C. for 5 minutes. Thus, test specimens c04
were obtained. Surface milling was conducted in the mid course, as
necessary, and thus the sheet thickness of the test specimens was
set to 0.2 mm. The principal production conditions are as described
below.
[Conditions of Example 1 of JP-A-2008-223136]
[0098] Hot-rolling ratio at below 700.degree. C. to 400.degree. C.:
56% (one pass)
[0099] Cold-rolling ratio before solution treatment: 92%
[0100] Cold-rolling ratio for intermediate cold-rolling: 20%
[0101] Cold-rolling ratio for finish cold-rolling: 30%
[0102] Time period for temperature rise from 100.degree. C. to
700.degree. C.: 10 seconds
[0103] The test specimens c04 thus obtained were different from
that in Example 1 according to this invention, in terms of the
slow-cooling down to 350.degree. C. after the hot-rolling, whether
conducted or not conducted, and the intermediate annealing and
cold-rolling before the solution treatment, whether conducted or
not conducted, in connection with the production conditions, and
resulted in a conspicuously high area ratio of the (1 1 1) plane
oriented toward the RD, and not satisfying the requirements on the
Young's modulus and the factor of bending deflection.
* * * * *