U.S. patent application number 10/657005 was filed with the patent office on 2004-08-26 for age-hardening copper-base alloy and processing.
This patent application is currently assigned to Olin Corporation. Invention is credited to Boegel, Andreas, Caron, Ronald N., Humpenoder-Bogel, Doris, Kuhn, Hans-Achim, Robinson, Peter W., Seeger, Joerg, Tyler, Derek E..
Application Number | 20040166017 10/657005 |
Document ID | / |
Family ID | 31994162 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040166017 |
Kind Code |
A1 |
Caron, Ronald N. ; et
al. |
August 26, 2004 |
Age-hardening copper-base alloy and processing
Abstract
An age-hardening copper-base alloy and processing method to make
a commercially useful strip product for applications requiring high
yield strength and moderately high electrical conductivity, in a
strip, plate, wire, foil, tube, powder or cast form. The alloys are
particularly suited for use in electrical connectors and
interconnections. The alloys contain Cu--Ti--X where X is selected
from Ni, Fe, Sn, P, Al, Zn, Si, Pb, Be, Mn, Mg, Ag, As, Sb, Zr, B,
Cr and Co. and combinations thereof. The alloys offer excellent
combinations of yield strength, and electrical conductivity, with
excellent stress relaxation resistance. The yield strength is at
least of 105 ksi and the electrical conductivity is at least 50%
IACS.
Inventors: |
Caron, Ronald N.; (Branford,
CT) ; Robinson, Peter W.; (Glen Carbon, IL) ;
Tyler, Derek E.; (Cheshire, CT) ; Boegel,
Andreas; (Weissenhorn, DE) ; Humpenoder-Bogel,
Doris; (US) ; Kuhn, Hans-Achim; (Illertissen,
DE) ; Seeger, Joerg; (Ulm, DE) |
Correspondence
Address: |
WIGGIN AND DANA LLP
ATTENTION: PATENT DOCKETING
ONE CENTURY TOWER, P.O. BOX 1832
NEW HAVEN
CT
06508-1832
US
|
Assignee: |
Olin Corporation
Wieland-Werke AG
|
Family ID: |
31994162 |
Appl. No.: |
10/657005 |
Filed: |
September 5, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60410592 |
Sep 13, 2002 |
|
|
|
Current U.S.
Class: |
420/492 ;
148/681; 148/682; 420/487; 420/488 |
Current CPC
Class: |
C22C 9/00 20130101; C22C
9/06 20130101 |
Class at
Publication: |
420/492 ;
420/487; 420/488; 148/681; 148/682 |
International
Class: |
C22C 009/00; C22F
001/08 |
Claims
1. A copper base alloy consisting essentially of, by weight: from
0.35% to 5% titanium; from 0.001% to 10% of X, where X is selected
from Ni, Fe, Sn, P, Al, Zn, Si, Pb, Be, Mn, Mg, Bi, S, Te, Se, Ag,
As, Sb, Zr, B, Cr and Co and combinations thereof; and the balance
copper and inevitable impurities, said alloy having an electrical
conductivity of at least 50% IACS and a yield strength of at least
105 ksi.
2. The copper base alloy of claim 1 wherein X is selected from the
group consisting of Ni, Fe, Co, Mg, Cr, Zr, Ag and combinations
thereof.
3. The copper base alloy of claim 2 further consisting essentially
of: from 0.35% to 2.5% titanium; from 0.5% to 5.0% nickel; from
0.5% to 0.8% of iron, cobalt and mixtures thereof; from 0.01% to
1.0% magnesium; up to 1% of Cr, Zr, Ag and combinations thereof;
and the balance copper and inevitable impurities.
4. The copper base alloy of claim 3 further consisting essentially
of: from 0.8% to 1.4% titanium; from 0.8% to 1.7% nickel; from 0.9%
to 1.1% of iron, cobalt and mixtures thereof; from 0.1% to 0.4%
magnesium; up to 1% of Cr, Zr, Ag and combinations thereof; and the
balance copper and inevitable impurities.
5. A copper base alloy having an improved combination of yield
strength, electrical conductivity, stress relaxation resistance
consisting essentially of by weight of: 0.35-2.5% titanium;
0.5-5.0% nickel; 0.5-1.5% iron, cobalt and mixtures thereof;
0.01-1.0% magnesium; up to 1% of Sn, Cr, Zr, Ag, Sn, P, Al, Zn, Si,
Pb, Bi, S, Te, Se, Be, Mn, As, Sb, Zr, B and mixtures thereof; and
the balance copper and inevitable impurities.
6. The copper base alloy of claim 5 containing up to 1% of Cr, Zr,
Ag and mixtures thereof.
7. The copper base alloy of claim 6 consisting essentially of
0.8-1.4% titanium; 0.8-1.7% nickel; 0.90-1.10% iron, or cobalt;
0.10-0.40% magnesium; 0.01% to 1.0% of Cr, Zr, Ag and mixtures
thereof; and the balance copper and inevitable impurities
8. A process for making a copper base alloy having an improved
combination of yield strength, electrical conductivity and stress
relaxation, comprising: casting a copper base alloy that consists
essentially, by weight, from 0.35% to 10% titanium, from 0.001% to
6% of X, where X is selected from Ni, Fe, Sn, P, Al, Zn, Si, Pb,
Be, Mn, Mg, Bi, S, Te, Se, Ag, As, Sb, Zr, B, Cr and Co and
combinations thereof and the balance copper and inevitable
impurities; hot rolling the alloy at from about 750.degree. C. to
about 1,000.degree. C.; first cold rolling the alloy to a reduction
in area of from about 50% to about 97%; first annealing the alloy
at a temperature of from about 850.degree. C. to about
1,000.degree. C. for from about 10 seconds to about one hour,
followed by a rapid cool to ambient; second cold rolling the alloy
up to about 80% reduction in area; second annealing the alloy at
from about 400.degree. C. to about 650.degree. C. for from about 1
minute to about 10 hours; third cold rolling the alloy from about a
10% to about a 50% reduction in area to finished gauge.
9. The process of claim 8 wherein following said third cold rolling
step, said alloy is annealed at a temperature of from about
150.degree. C. to about 600.degree. C. for from about 15 seconds to
about 10 hours.
10. The process of claim 9 wherein said first, second and third
annealing steps have times and temperatures effective for said
alloy to have a yield strength of at least 105 ksi and an
electrical conductivity of at least 50% IACS at finish gauge.
11. A process for making a copper base alloy having an improved
combination of yield strength, electrical conductivity, stress
relaxation resistance, along with modest levels of bendability
comprising: casting a copper base alloy that consists essentially,
by weight, from 0.35% to 10% titanium, from 0.001% to 6% of X,
where X is selected from Ni, Fe, Sn, P, Al, Zn, Si, Pb, Be, Mn, Mg,
Bi, S, Te, Se, Ag, As, Sb, Zr, B, Cr and Co and combinations
thereof and the balance copper and inevitable impurities; hot
reducing the alloy at from about 750.degree. C. to about
1,000.degree. C.; providing one or more cycles comprising cold
reducing the alloy to a reduction in area of from about 50% to
about 99% and then age annealing at an annealing temperature of
from about 400.degree. C. to about 650.degree. C. for from about 15
secs. to about 10 hours; cold reducing the alloy from about 40% to
about 80% reduction in area; age hardening the alloy by annealing
at from about 400.degree. C. to about 650.degree. C. for from about
1 to about10 hours; and final reducing the alloy from about a 10%
to about a 50% reduction in area to finished gauge.
12. The process of claim 11 wherein following said final cold
rolling step, said alloy is annealed at a temperature of from about
150.degree. C. to about 600.degree. C. for from about 15 seconds to
about 10 hours.
13. The process of claim 12 wherein said annealing steps have times
and temperatures effective for said alloy to have a yield strength
of at least 105 ksi and an electrical conductivity of at least 50%
at finish gauge.
14. A process for making a copper base alloy having high yield
strength and moderate strength, electrical conductivity comprising:
casting a copper base alloy that consists essentially, by weight,
from 0.35% to 10% titanium, from 0.001% to 6% of X, where X is
selected from Ni, Fe, Sn, P, Al, Zn, Si, Pb, Be, Mn, Mg, Bi, S, Te,
Se, Ag, As, Sb, Zr, B, Cr and Co and combinations thereof and the
balance copper and inevitable impurities; hot reducing the alloy at
from about 750.degree. C. to about 1,000.degree. C.; cold reducing
the alloy to a reduction in area of from about 50% to about 99%;
solution annealing the alloy at a temperature of from about
950.degree. C. to about 1,000.degree. C. for from about 15 seconds
to about one hour, followed by a rapid cool to ambient; cold
reducing the alloy from about 40% to about a 60% reduction in area;
age annealing the alloy at a temperature of about 400.degree. C. to
about 650.degree. C. for from about 1 to about 10 hours; cold
reducing the alloy from about a 40% to about a 60% reduction in
area; age annealing the alloy a second time at a lower temperature
than the first aging anneal of from about 375.degree. C. to about
550.degree. C. for from about 1 to about 3 hours; and cold reducing
at least about 30% reduction in area to a finished gauge.
15. The process of claim 14 wherein following said final cold
rolling step, said alloy is annealed at a temperature of from about
150.degree. C. to about 600.degree. C. for from about 15 seconds to
about 10 hours.
16. The process of claim 15 wherein said first, second and third
annealing steps have times and temperatures effective for said
alloy to have a yield strength of at least 105 ksi and an
electrical conductivity of at least 50% IACS at finish gauge.
17. A process for making a copper base alloy having high yield
strength and moderate strength, electrical conductivity comprising:
casting a copper base alloy that consists essentially, by weight,
from 0.35% to 10% titanium, from 0.001% to 6% of X, where X is
selected from Ni, Fe, Sn, P, Al, Zn, Si, Pb, Be, Mn, Mg, Bi, S, Te,
Se, Ag, As, Sb, Zr, B, Cr and Co and combinations thereof and the
balance copper and inevitable impurities; hot rolling the alloy at
from about 750.degree. C. to about 1,000.degree. C.; cold rolling
the alloy to a reduction in area of from about 50% to about 99%;
solution annealing the alloy at a temperature of from about
950.degree. C. to about 1,000.degree. C. for from about 10 seconds
to about one hour, followed by a rapid cool to ambient; cold
rolling the alloy from about a 40% to about a 60% reduction in
area; age annealing the alloy at a temperature of about 500.degree.
C. to about 575.degree. C. for from about 15 seconds to about 10
hours or at a temperature of about 425 to about 475.degree. C. for
about 2.5 to about 3.5 hours; cold rolling the alloy from about a
40% to about a 60% reduction in area; age annealing the alloy a
second time at a temperature of from about 500.degree. C. to about
550.degree. C. for from about 1 to about 4 hours; and final rolling
at least about 30% reduction in area to a finished gauge.
18. The process of claim 17 wherein following said final cold
rolling step, said alloy is annealed at a temperature of from about
150.degree. C. to about 600.degree. C. for from about 15 seconds to
about 10 hours.
19. The process of claim 18 wherein said annealing steps have times
and temperatures effective for said alloy to have a yield strength
of at least 105 ksi and an electrical conductivity of at least 50%
at finish gauge.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This patent application claims priority to U.S. Provisional
Patent Application Serial No. 60/410,592, entitled "Age-Hardening
Copper-Base Alloy and Processing," that was filed on Sep. 13, 2002.
The subject matter of that provisional patent application is
incorporated by reference in its entirety herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to an age-hardening copper-base alloy
and a processing method to make commercially useful products from
that alloy. More particularly, a copper alloy containing from 0.35%
to 5%, by weight, titanium is wrought to finish gauge by a process
that includes an in-process solution anneal and at least one age
anneal. The resultant product has an electrical conductivity in
excess of 50% IACS and a yield strength in excess of 105 ksi.
[0004] 2. Description of Related Art
[0005] Throughout this patent application, all compositions are in
weight percent and all mechanical and electrical testing was
performed at room temperature (nominally 22.degree. C.), unless
otherwise specified. The word "about" implies.+-.10% and the word
"base" as in copper-base, means the alloy contains at least 50%, by
weight, of the specified base element. The terms "rolling" or
"rolled" are intended to encompass drawing or drawn or any other
form of cold reduction, for example, as used in the manufacture and
processing of wire, rod or tubing.
[0006] Many different types of electrical connectors are formed
from copper-base alloys. Properties important for an electrical
connector include yield strength, bend formability, resistance to
stress relaxation, modulus of elasticity, ultimate tensile strength
and electrical conductivity.
[0007] Target values for these properties and the relative
importance of the properties are dependent on the intended
application of products manufactured from the subject copper
alloys. The following property descriptions are generic for many
intended applications, but the target values are specific for under
the hood automotive applications.
[0008] The yield strength is the stress at which a material
exhibits a specified deviation, typically an offset of 0.2%, from
proportionality of stress and strain. This is indicative of the
stress at which plastic deformation becomes dominant with respect
to elastic deformation. It is desirable for copper alloys utilized
as connectors to have a yield strength of at least 105 ksi, that is
at least approximately 724 MPa.
[0009] Stress relaxation becomes apparent when an external stress
is applied to a metallic strip in service, such as when the strip
is loaded after having been bent into a connector. The metal reacts
by developing an equal and opposite internal stress. If the metal
is held in a strained position, the internal stress will decrease
as a function of both time and temperature. This phenomenon occurs
because of the conversion of elastic strain in the metal to
plastic, or permanent strain, by microplastic flow.
[0010] Copper based electrical connectors must maintain above a
threshold contact force on a mating member for prolonged times for
good electrical connection. Stress relaxation reduces the contact
force to below the threshold leading to an open circuit. It is
desirable for a copper alloy for connector applications to maintain
at least 95% of the initial stress when exposed to a temperature of
105.degree. C. for 1000 hours and to maintain at least 85% of the
initial stress when exposed to a temperature of 150.degree. C. for
1000 hours.
[0011] The modulus of elasticity, also known as Young's modulus, is
a measure of the rigidity or stiffness of a metal and is the ratio
of stress to corresponding strain in the elastic region. Since the
modulus of elasticity is a measure of the stiffness of a material,
a high modulus, on the order of 140 Gpa (20.times.10.sup.3 ksi) is
desirable.
[0012] Bendability determines the minimum bend radius (MBR) which
identifies how severe a bend may be formed in a metallic strip
without fracture along the outside radius of the bend. The MBR is
an important property for connectors where different shapes are to
be formed with bends at various angles.
[0013] Bend formability may be expressed as, MBR/t, where t is the
thickness of the metal strip. MBR/t is a ratio of the minimum
radius of curvature of a mandrel about which the metallic strip can
be bent without failure to the thickness of the strip. The
"mandrel" test is specified in ASTM (American Society for Testing
and Materials) designation E290-92, entitled Standard Test Method
for Semi-Guided Bend Test for Ductility of Metallic Materials, and
is incorporated by reference in its entirety herein.
[0014] It is desirable for the MBR/t to be substantially isotropic,
a similar value in the "good way", bend axis perpendicular to the
rolling direction of the metallic strip, as well as the "bad way",
bend axis parallel to the rolling direction of the metallic strip.
It is desirable for the MBR/t to be about 1.5 or less for a
90.degree. bend and about 2 or less for a 180.degree. bend.
[0015] Alternatively, the bend formability for a 90.degree. bend
may be evaluated utilizing a block having a V-shaped recess and a
punch with a working surface having a desired radius. In the
"V-block" method, a strip of the copper alloy in the temper to be
tested is disposed between the block and the punch and when the
punch is driven down into the recess, the desired bend is formed in
the strip.
[0016] Related to the V-block method is the 180.degree. "form
punch" method in which a punch with a cylindrical working surface
is used to shape a strip of copper alloy into a 180.degree.
bend.
[0017] Both the V-block method and the form punch method are
specified in ASTM designation B820-98, entitled Standard Test
Method for Bend Test for Formability of Copper Alloy Spring
Material, that is incorporated by reference in its entirety
herein.
[0018] For a given metal sample, both methods give quantifiable
bendability results and either method may be utilized to determine
relative bendability.
[0019] The ultimate tensile strength is a ratio of the maximum load
a strip withstands before failure during a tensile test divided by
the initial cross-sectional area of the strip. It is desirable for
the ultimate tensile strength to be about 110 ksi, that is
approximately 760 MPa.
[0020] Electrical conductivity is expressed in % IACS
(International Annealed Copper Standard) in which unalloyed copper
is defined as having an electrical conductivity of 100% IACS at
20.degree. C.
[0021] Copper-base alloys containing titanium are disclosed in U.S.
Pat. Nos. 4,601,879 and 4,612,167, among others. The, 4,601,879
patent discloses a copper-base alloy containing 0.25% to 3.0% of
nickel, 0.25% to 3.0% of tin and 0.12% to 1.5% of titanium.
Exemplary alloys have an electrical conductivity of between 48.5%
and 51.4% IACS and a yield strength of between 82.5 ksi and 84
ksi.
[0022] The 4,612,167 patent discloses a copper alloy containing
0.8% to 4.0% of nickel and 0.2% to 4.0% of titanium. Exemplary
alloys have an electrical conductivity of 51% IACS and a yield
strength of 96.2 ksi to 98.5 ksi. Both the 4,601,879 patent and the
4,612,167 patent are incorporated by reference in their entireties
herein.
[0023] AMAX Copper, Inc. (Greenwich, Conn.) has commercialized
copper-nickel-titanium alloys having nominal compositions of Cu-2%
Ni-1% Ti and Cu-5% Ni-2.5% Ti. The reported properties for the
Cu-2% Ni-1% Ti alloy are yield strength 64-80 ksi; ultimate tensile
strength 73-95 ksi; elongation 9%; and electrical conductivity
50-60% IACS. The reported properties for the Cu-5% Ni-2.5% Ti alloy
are yield strength 90-100 ksi; ultimate tensile strength 108 ksi
UTS; elongation 10%; and electrical conductivity 40-53% IACS.
[0024] Many current and future applications for these copper alloys
will require an electrical conductivity of at least 50% IACS and a
yield strength of at least 105 ksi. There remains a need for
copper-titanium alloys and processes for manufacturing the
copper-titanium alloys capable of achieving the required levels of
electrical conductivity and strength.
SUMMARY OF THE INVENTION
[0025] In accordance with the invention, there is provided an
age-hardening copper-base alloy and methods to process this alloy
to form a commercially useful product for any application requiring
high yield strength and moderately high electrical conductivity.
Typical forms for the product include strip, plate, wire, foil,
tube, powder or cast form. The alloys when processed according to
the methods of the invention achieve a yield strength of at least
105 ksi and an electrical conductivity of 50% IACS making the
alloys particularly suited for use in electrical connectors and
interconnections.
[0026] The alloys consisting essentially of, by weight, from 0.35%
to 5% titanium, from 0.001% to 10% of X, where X is selected from
Ni, Fe, Sn, P, Al, Zn, Si, Pb, Be, Mn, Mg, Bi, S, Te, Se, Ag, As,
Sb, Zr, B, Cr and Co and combinations thereof and the balance is
copper and inevitable impurities. The alloy has an electrical
conductivity of at least 50% IACS and a yield strength of at least
105 ksi.
[0027] In a preferred aspect of the invention, the alloy consists
essentially of from 0.35% to 2.5% titanium, from 0.5% to 5.0%
nickel, from 0.5% to 0.8% of iron, cobalt and mixtures thereof,
from 0.01% to 1.0% magnesium, up to 1% of Cr, Zr, Ag and
combinations thereof and the balance is copper and inevitable
impurities.
[0028] These alloys, when beryllium is not present, avoid the
potentially dangerous health issues associated with current
beryllium-copper alloys, while offering similar combinations of
strength and conductivity.
[0029] Brief Description of the Several Drawings
[0030] FIG. 1 illustrates in flow chart format a first method for
processing the copper alloys of the invention.
[0031] FIG. 2 illustrates in flow chart format a second method for
processing the copper alloys of the invention.
[0032] FIG. 3 illustrates in flow chart format a third method for
processing the copper alloys of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Copper alloys having a combination of strength and
electrical conductivity, as well as good formability and a
resistance to stress relaxation are in demand for many electrical
current carrying applications. Two exemplary applications are
under-the-hood automotive applications and multimedia applications
(such as computers, DVD players, CD readers and the like).
[0034] For automotive applications, there is a need for copper
alloys with good formability, an electrical conductivity of at
least 50% IACS and stress relaxation resistance up to 200.degree.
C. For multimedia interconnect applications, there is a need for
copper alloys with a yield strength in excess of 105 ksi, an
electrical conductivity in excess of 50% IACS and mechanical
stability at room and slightly higher service temperatures, as
characterized, by excellent stress relaxation resistance at about
100.degree. C.
[0035] The alloy compositions when processed by the methods of this
invention surprisingly provide an optimum combination of properties
for meeting the needs for both automotive and multimedia
applications, as well as other electrical and electronic
applications. The alloys can provide moderately high strength along
with high conductivity and moderately high conductivity along with
very high strength.
[0036] The alloys of the present invention have compositions
containing Cu--Ti--X, where X is selected from Ni, Fe, Sn, P, Al,
Zn, Si, Pb, Bi, S, Te, Se, Be, Mn, Mg, Ag, As, Sb, Zr, B, Cr and Co
and combinations thereof. The titanium content is from 0.35% to 5%
and the sum total of the "X" elements is from 0.001% to 10%.
[0037] Strength and electrical conductivity are maximized when X is
selected from the group consisting of Ni, Fe, Co, Mg, Cr, Zr, Ag
and mixtures thereof.
[0038] Oxygen, sulfur and carbon may be present in the alloys of
the invention in amounts typically found in either electrolytic
(cathode) copper or remelted copper or copper alloy scrap.
Typically, the amount of each of these elements will be in the
range of from about 2 ppm to about 50 ppm and preferably, each is
present in an amount of less than 20 ppm.
[0039] Other additions that influence the properties of the alloy
may also be included. Such additions include those that improve the
free machinability of the alloy, such as bismuth, lead, tellurium,
sulfur and selenium. When added to enhance free machinability,
these additions may be present in an amount of up to 2%.
Preferably, the total of free machinability additions is between
about 0.8% and 1.5%.
[0040] Typical impurities found in copper alloys, particularly in
copper alloys formed from recycled or scrap copper, may be present
in an amount of up to about 1%, in total. As a non-exclusive list,
such impurities include magnesium, aluminum, silver, silicon,
cadmium, bismuth, manganese, cobalt, germanium, arsenic, gold,
platinum, palladium, hafnium, zirconium, indium, antimony,
chromium, vanadium, and beryllium. Each impurity should be present
in an amount of less than 0.35%, and preferably in an amount of
less than 0.1%.
[0041] It should be recognized that some of the above-recited
impurities, or others, in amounts overlapping the above specified
impurity ranges, may have a beneficial effect on the copper alloys
of the invention. For example, strength or stampability may be
improved. This invention is intended to encompass such low level
additions.
[0042] In a more preferred embodiment of the invention, the
titanium content is from 0.35% to 2.5% and in a most preferred
embodiment, the titanium content is from 0.8% to 1.4%
[0043] When the titanium is in solution in the copper alloy matrix,
electrical conductivity is severely degraded. Therefore, "X" should
preferably be effective to cause titanium to precipitate from
solution during an age anneal. Suitable elements for "X" to enhance
such precipitation include Ni, Fe, Sn, P, Al, Si, S, Mg, Cr, Co and
combinations of these elements.
[0044] One preferred addition is nickel. A combination of Ni and Ti
provides precipitates of CuNiTi and the presence of Fe and Ti
provides precipitates of Fe.sub.2Ti.
[0045] Another preferred addition is magnesium. An addition of Mg
increases stress relaxation resistance and softening resistance in
finished gauge and temper products. The Mg also provides softening
resistance during in-process aging annealing heat treatments.
[0046] When present at low levels, additions of Cr, Zr and/or Ag
provide increased strengthening without unduly reducing
conductivity.
[0047] One preferred alloy in accordance with the invention that
has an improved combination of yield strength, electrical
conductivity, stress relaxation resistance, along with modest
levels of bendability consists essentially of
[0048] about 0.5-5.0% Nickel
[0049] about 0.35-2.5% Titanium
[0050] about 0.5-0.8% Iron or Cobalt
[0051] about 0.01-1.0% Magnesium,
[0052] with optionally up to about 1.0% of one or more of Sn, P,
Al,
[0053] Zn, Si, Pb, Bi, S, Te, Se, Be, Mn, Mg, Ag, As, Sb, Zr, B, Cr
and
[0054] mixtures thereof, and the balance copper and impurities.
[0055] Preferably the optional elements comprise up to 1% of one or
more of Cr, Zr and Ag.
[0056] More preferred ranges for this alloy are:
[0057] about 0.8-1.7% Nickel
[0058] about 0.8-1.4% Titanium
[0059] about 0.90-1.10% Iron, or Cobalt
[0060] about 0.10-0.40% Magnesium,
[0061] with up to about 1.0% of one or more of Cr, Zr, Ag or Sn
and
[0062] mixtures thereof,
[0063] and the balance Copper and impurities
[0064] In a first embodiment of the invention, the alloy
composition and processing provide a yield strength of at least
about 115 ksi and preferably a yield strength of at least about 120
ksi. For this embodiment, the conductivity is up to about 40% IACS.
In a second embodiment of the invention, the composition and
processing provide a yield strength of more than about 105 ksi, and
preferably up to about 115 ksi. In this second embodiment, the
electrical conductivity of the alloy is preferably from about 45%
to about 55% IACS. In a third embodiment, the composition and
processing provide a yield strength of from about 80 ksi to about
100 ksi and the electrical conductivity is between about 55% and
about 65% IACS.
[0065] FIG. 1 illustrates in flow chart format, a process in
accordance with a first embodiment of the invention. The alloy of
the invention is melted and cast 10 in accordance with conventional
practice. The cast alloy is hot rolled 12 at from about 750.degree.
C. to about 1,000.degree. C. After milling to remove oxide, the
alloy is then cold rolled 14 to a reduction in cross-sectional area
transverse to the rolling direction ("reduction in area") of from
about 50% to about 99%. The alloy may then be solutionized 16 at a
solution annealing temperature of from about 850 to about
1,000.degree. C. for from about 10 seconds to about one hour,
followed by a quench 18 or rapid cool to ambient temperature to
obtain equiaxed grains with an average grain size of about 5 and 20
.mu.m. Thereafter the alloy may be first cold rolled 20 up to about
80% reduction in area, preferably about 30% to about 80% reduction
in area. The first cold roll 20 is followed by a first anneal 22 at
a temperature of from about 400.degree. C. to about 650.degree. C.
and preferably from about 450.degree. C. to about 600.degree. C.
for from about 1 minute to about 10 hours and preferably from about
1 to about 8 hours. The alloy is then second cold rolled 24 from
about a 10% to about a 50% reduction in area to finished gauge. The
second cold roll may be followed by a second anneal 26 at about
150.degree. C. to about 600.degree. C. and preferably from about
200.degree. C. to about 500.degree. C. for from about 15 seconds to
about 10 hours.
[0066] Alternatively in accordance with another embodiment, the
alloy is processed to finished gauge without using an in-process
solutionizing heat treatment. That is, it can be processed to
finish using cycles of lower temperature annealing treatments and
intervening cold work. This alternative process is especially
useful for making a product with higher electrical conductivity
levels.
[0067] FIG. 2 illustrates in flow chart representation an
alternative process of the invention. The alloy of the invention is
melted and cast 10 in accordance with conventional practice. The
cast alloy is hot rolled 12 at from about 750.degree. C. to about
1,000.degree. C. and then quenched or quickly cooled. After milling
to remove oxide, the hot rolled alloy is then cold rolled 14 to a
reduction in area of from about 50% to about 99%. The alloy may
then be first annealed 28 at an annealing temperature of from about
400.degree. C. to about 650.degree. C. for from about 15 secs. to
about 10 hours. The cold rolling and first annealing steps may
optionally be repeated, if desired The alloy is then cold rolled 30
from about 40% to about 80% reduction in area followed by a second
anneal 32 at from about 400.degree. C. to about 650.degree. C. and
preferably from about 450.degree. C. to about 600.degree. C. for
from about 1 to about 10 hours. The alloy is then cold rolled 34
from about a 10% to about a 50% reduction in area to finished
gauge. This may optionally be followed by a third anneal 26 at
about 150.degree. C. to about 600.degree. C. and preferably from
about 200.degree. C. to about 500.degree. C. for from about 15
seconds to about 10 hours.
[0068] A second alternative preferred embodiment of the process of
this invention employs an alloy in the preferred composition
ranges. This process is capable of making the alloy of this
invention with nominal properties of about 110 ksi YS and about 50%
IACS conductivity. With reference to FIG. 3, the alloy is melted
and cast 10 in accordance with conventional practice. The cast
alloy is hot rolled 12 at from about 750.degree. C. to about
1,000.degree. C. After milling to remove oxide the hot rolled alloy
is then cold rolled 14 to a reduction in area of from about 50% to
about 99%. The alloy is then solutionized 16 at a temperature of
from about 950.degree. C. to about 1,000.degree. C. for from about
15 seconds to about 1 hour. The alloy is next cold rolled 20 to
from about a 40% to about a 60% reduction in area and then first
annealed 28 at about 400.degree. C. to about 650.degree. C. and
preferably 450.degree. C. to about 600.degree. C. for from about 1
to about 10 hours and preferably from about 1 to about 3 hours. The
first anneal 28 is followed by cold rolling 30 from about a 40% to
about a 60% reduction in area. The alloy is then second annealed 32
at a lower temperature than the first anneal 28. The second anneal
is at a temperature of from about 375.degree. C. to about
550.degree. C. for from about 1 to about 3 hrs. The doubly annealed
alloy is then cold rolled 34 at least about 30% reduction in area
to a finished gauge where it may be annealed a third time 26 at a
temperature of from about 150.degree. C. to about 600.degree. C.
and preferably from about 200.degree. C. to about 500.degree. C.
for from about 1 to about 3 hours.
[0069] The alloys of the invention and the processes of the
invention are better understood with reference to the Examples that
follow.
EXAMPLES
[0070] In the examples that follow some of the process
descriptions, properties and units are written in an abbreviated
form. For example, "=inches, WQ=water quench, a slash mark/=for,
SA=solution anneal, CR=cold rolled or cold reduced, YS=yield
strength, TS=tensile strength, EL=elongation, % IACS=electrical
conductivity, MBR/t=minimum bend radius divided by the strip
thickness, SR=stress relaxation resistance, Gs=grain size,
.mu.m=microns or micrometers, beg.=begin, recr.=recrystallized,
n.c.r.=not completely recrystallized, sec. or s=seconds, hrs. or
h=hours, MS/m=mega-siemens per meter and ksi=thousands of pounds
per square inch.
Example 1
[0071] Utilizing the process illustrated in FIG. 1, a series of ten
pound laboratory ingots with the analyzed compositions listed in
Table 1 were melted in a silica crucible and Durville cast into
steel molds. After gating the ingots were 4".times.4".times.1.75".
After soaking for three hours at 950.degree. C., the ingots were
hot rolled in three passes to 1.1", reheated at 950.degree. C. for
ten minutes, and further hot rolled in three passes to 0.50",
followed by a water quench. The resultant hot rolled plates were
homogenized by soaking for two hours at 1,000.degree. C. followed
by a water quench. After trimming and milling to remove oxide
coating, the alloys were cold rolled to 0.050". The alloys were
then solutionized at a temperature of 1000.degree. C. for from 20
to 60 seconds, with the exception of alloy J346 which was
solutionized at 950.degree. C. for 60 seconds. Following
solutionization and quenching, the alloys were cold rolled 50% to
0.025" and age annealed at 550.degree. C. for 3 hours The alloys
were then cold rolled 50% to 0.0125" gauge and relief annealed at
275.degree. C. for 2 hours and the properties reported in Table 2
measured.
[0072] The data in Table 2 show that high values of yield strength,
from 90 ksi to 111 ksi, and electrical conductivity, from 38.2%
IACS to 63.8% IACS were obtained. The stress relaxation resistance
obtained was close to the desired value of 95% after 1000 hours at
105.degree. C. for the Cu--Ni--Ti--Fe alloys J345 and J346. The
desired value was achieved by the Cu--Ni--Ti--Mg alloy J354.
1TABLE 1 Alloys of Example 1 Alloy Identification Number (ID)
Analyzed composition, wt % J345 Cu-2.32 Ni-1.96 Ti-1.06 Fe J346
Cu-1.16 Ni-1.32 Ti-0.92 Fe J347 Cu-0.80 Ni-0.80 Ti J348 Cu-0.89
Ni-1.82 Ti-1.04 Fe J351 Cu-2.45 Ni-1.16 Ti J354 Cu-2.43 Ni-1.18
Ti-0.38 Mg
[0073]
2TABLE 2 Properties for the Relief Annealed Condition for Alloys
Listed in Table 1 90.degree.-MBR/t % SR % SR Alloy Cond good way/
105.degree. C. 105.degree. C. ID % IACS YS/TS/EI bad way 1,000 h
3,000 h J345 42.9 106/122/2 2.7/8.8 90.4 89.5 J346 56.1 97/102/3
1.4/2.9 88.2 87.3 J347 34.6 106/117/1 2.7/8.8 -- -- J348 38.2
111/124/4 1.9/7.5 -- -- J351 63.8 90/93/1 1.4/2.2 -- -- J354 47.0
109/115/2 5.0/8.8 95.1 93.9
Example 2
[0074] In accordance with the process illustrated in FIG. 2, the
alloys of Table 1 were processed as in Example 1 up through the
homogenization heat treatment at hot rolled plate gauge. In this
example, the alloys were processed to finish gauge without an
in-process solutionizing heat treatment. After trimming and milling
to remove the oxide coating, the alloys were cold rolled to 0.100"
and given a first aging anneal at 550.degree. C. for 3 hours. The
alloys were then cold rolled 70% to 0.030" and subjected to a
second aging anneal at 525.degree. C. for 3 hours. The alloys were
then cold rolled 50% to 0.015" gauge and relief annealed
275.degree. C. for 2 hrs in which condition the properties recited
in Table 3 were measured.
[0075] Consistent with the data in Table 2, the alloys of this
example had a combination of a high yield strength, from 98 ksi to
107 ksi, but with higher electrical conductivity of between 49.9%
IACS and 69.7% IACS. Enhanced stress relaxation resistance is
obtained when either Fe or Mg is added to the base Cu--Ni--Ti
alloy. The data in Table 3 show that the highest stress relaxation
resistance obtained with a Mg addition to a Cu--Ni--Ti alloy;
compare alloy J354 to alloy J351.
3TABLE 3 Properties for the Relief Annealed Condition for Alloys
Listed in Table 1 % SR % SR Alloy Cond. 105.degree. C. 105.degree.
C. ID % IACS YS/TS/EI 90.degree.-MBR/t 1,000 h 3,000 h J345 57.8
107/115/4 3.1/4.2 86.9 85.9 J346 63.2 98/104/5 0.8/4.2 85.8 84.7
J347 49.9 105/111/3 0.8/5.2 -- -- J348 58.8 104/112/6 2.1/5.2 -- --
J351 69.7 98/104/4 0.8/0.8 82.7 80.8 J354 60.8 101/108/5 2.4/4.2
92.4 90.4
Example 3
[0076] In accordance with the process illustrated in FIG. 1, a
series of ten pound laboratory ingots with the analyzed
compositions listed in Table 4 were melted in silica crucibles and
Durville cast into steel molds. After gating the ingots were
4".times.4".times.1.75". After soaking three hours at 950.degree.
C. they were hot rolled in three passes to 1.1" thick, reheated at
950.degree. C./ten minutes, and further hot rolled in three passes
to 0.50" thick, followed by a water quench. After trimming and
milling to remove the oxide coating, the alloys were cold rolled to
0.050".
[0077] The alloys other than J477 were then solution heat treated
at 1,000.degree. C. for 25 seconds followed by a water quench to
yield a controlled, fine, recrystallized grain size in the range
12-24 .mu.m in diameter. Alloy J477 was solution heat treated at
950.degree. C./25 secs+WQ, yielding a grain size of 9 .mu.m.
[0078] All alloys were then cold rolled 50% to 0.025" thick and
subjected to an aging anneal at 550.degree. C. for a time effective
to maximize electrical conductivity without unduly softening the
matrix. The times at 550.degree. C. are reported in Table 5. The
alloys were then cold rolled 50% to 0.0125" gauge and relief
annealed at 275.degree. C. for 2 hrs at which condition the
properties in Table 5 were measured.
[0079] The data in Table 5 show that, while the base alloy J477
offers a good combination of properties (92 ksi YS and 58.1% IACS
conductivity), the Fe addition increases the strength of the base
alloy (J483 versus J477) to 100 ksi with only a slight reduction in
electrical conductivity. Moreover, the advantage of the Mg
addition, while maintaining consistent amounts of Ni, Ti and Fe,
for increasing stress relaxation resistance at 105.degree. C. is
shown by comparing alloy J491 to J481. The advantage of Mg is also
shown by comparison of the properties of alloy J491 (Table 5)
compared to those of J345 and J346 in Table 2.
4TABLE 4 Alloys of Example 3 Alloy Identification No. Analyzed
composition, wt % J477 Cu-1.41 Ni-0.71 Ti J481 Cu-1.00 Ni-0.98
Ti-0.99 Fe J483 Cu-1.42 Ni-0.87 Ti-0.53 Fe J485 Cu-0.97 Ni-1.40
Ti-1.01 Fe J486 Cu-1.86 Ni-1.43 Ti-0.98 Fe J491 Cu-0.98 Ni-0.94
Ti-1.00 Fe-0.35 Mg
[0080]
5TABLE 5 Properties in the relief annealed condition for alloys
listed in Table 4 % SR % SR Alloy 550.degree. C./ Cond. 90.degree.-
1,000 hrs. 1,000 hrs. ID No. hrs % IACS YS/TS/EI MBR/t 105.degree.
C. 150.degree. C. J477 3 58.1 92/96/1 1.1/1.8 J481 5 56.6 96/100/4
1.1/1.8 92 90 J483 8 54.0 100/104/3 1.8/2.2 93 86 J485 8 53.6
101/106/5 0.8/2.1 J486 8 52.8 102/106/1 J491 8 55.0 98/102/5
1.4/2.4 96 86
Example 4
[0081] IN accordance with the process illustrated in FIG. 2, the
alloys of Table 4 were processed to finish gauge without using an
in-process solutionizing heat treatment. After trimming and milling
to remove the oxide coating, the alloys in the as hot rolled
condition were cold rolled to 0.050" gauge and given a first aging
anneal at a temperature and time as shown in Table 6 effective to
maximize electrical conductivity. The alloys were then cold rolled
50% to 0.025" gauge and subjected to a second aging anneal at a
temperature and time as shown in Table 6 selected to maximize the
conductivity without unduly softening the matrix. The specific
aging anneals applied to each alloy are noted in Table 6. The
alloys were then cold rolled 50% to 0.0125" gauge and relief
annealed at 275.degree. C. for 2 hrs. at which condition the
properties in Table 7 were measured. Using this process, the alloys
with Fe and Mg additions provide lower, but still good, strength
with higher electrical conductivity and good stress relaxation
resistance.
6TABLE 6 Aging anneals applied to the alloys in Example 4 Aging
treatment Alloy at 0.050" Aging treatment YS, ksi/ Identity gauge
at 0.025" gauge Conductivity % IACS J477 525.degree. C./2 hrs
450.degree. C./1 hr 76/69.4% J481 550.degree. C./2 hrs 500.degree.
C./1 hr 62/69.4% J483 550.degree. C./2 hrs 500.degree. C./1 hr
80/65.1% J485 550.degree. C./4 hrs 500.degree. C./1 hr 80/65.2%
J486 550.degree. C./2 hrs 450.degree. C./1 hr 70/66.6% J491
550.degree. C./4 hrs 500.degree. C./1 hr 65/61.0%
[0082]
7TABLE 7 Properties for the relief annealed condition for alloys
listed in Table 4 CR 0.0125" + relief annealed 275.degree. C./2 hrs
% SR % SR Cond 90.degree.- 105.degree. C. 150.degree. C. Alloy ID %
IACS YS/TS/EI MBR/t 1,000 hrs. 1,000 hrs. J477 64.1 84/91/3 1.8/3.8
J481 68.1 79/88/4 1.7/1.9 82 76 J483 62.5 88/94/4 1.8/2.2 86 82
J485 61.3 93/102/5 1.8/3.8 J486 64.8 83/92/5 J491 60.3 89/94/5
1.9/2.2 94 77
Example 5
[0083] In accordance with the process illustrated in FIG. 3, a
series of ten pound laboratory ingots with the analyzed
compositions listed in Table 8 were melted in silica crucibles and
Durville cast into steel molds After gating the ingots were
4".times.4".times.1.75". After soaking three hours at 950.degree.
C. they were hot rolled in three passes to 1.1" thick, reheated at
950.degree. C. for ten minutes, and further hot rolled in three
passes to 0.50" gauge, followed by a water quench. After trimming
and milling to remove the oxide coating, the alloys were cold
rolled to 0.100" thick and solution heat treated in a furnace at
950.degree. C. for 40 seconds followed by a water quench to yield a
controlled, fine, recrystallized grain size in the range 8.0-12
.mu.m. They were then cold rolled 50% to 0.050" gauge and subjected
to an aging anneal at 565.degree. C. for 3 hrs, designed to
maximize the conductivity without unduly softening the matrix. The
alloys were then cold rolled 50% to 0.025" gauge and given a second
aging anneal of 410.degree. C. for 2 hrs, cold rolled to 0.010".
This was followed by a relief anneal of 250.degree. C. for 2 hrs
for which condition the properties in Table 9 were measured.
8TABLE 8 Alloys of Example 5 Alloy Identification Number Analyzed
composition, wt % J694 Cu-1.78 Ni-1.34 Ti-0.98 Fe-0.24 Mg J698
Cu-1.72 Ni-1.42 Ti-1.02 Fe-0.24 Mg-0.06 Zr J699 Cu-1.72 Ni-1.35
Ti-1.01 Fe-0.23 Mg-0.60 Ag J700 Cu-1.75 Ni-1.37 Ti-1.01 Fe-0.23
Mg-0.53 Cr
[0084]
9TABLE 9 Properties for the relief annealed condition for alloys
listed in Table 8 410.degree. C./ CR 0.010" + 250.degree. C./2 hrs
Alloy 2 h, 0.025" Cond 90.degree.- ID Ni/Ti (Ni + Fe)/Ti YS, ksi %
IACS YS/TS/EI MBR/t J694 1.3 2.1 94 50.9 108/116/3 2.2/9.4 J698 0.8
1.9 93 51.3 111/119/3 2.6/7.8 J699 1.3 2.0 90 51.9 112/119/2
2.8/10.9 J700 1.3 2.0 93 49.5 110/118/2 2.6/6.2
[0085] Comparing baseline alloy J694 to zirconium containing alloy
J698 demonstrates that a small amount of zirconium increases the
yield strength without affecting electrical conductivity. A
comparison of alloy J694 with silver containing alloy J699
demonstrates that a small amount of silver increases both the yield
strength and the electrical conductivity. A comparison of alloy
J694 with chromium containing alloy J700 demonstrates that an
addition of a small amount of chromium increases the yield strength
slightly with a slight penalty in electrical conductivity.
Example 6
[0086] In accordance with the process illustrated in FIG. 3, a
series of ten pound laboratory ingots with the analyzed
compositions listed in Table 10 were melted in silica crucibles and
Durville cast into steel molds. After gating the ingots were
4".times.4".times.1.75". After soaking three hours at 950.degree.
C. they were hot rolled in three passes to 1.1" thick, reheated at
950.degree. C. for ten minutes, and further hot rolled in three
passes to 0.50" thick, followed by a water quench. After trimming
and milling to remove the oxide coating, the alloys were cold
rolled to 0.100" gauge and solution heat treated in a furnace at
1,000.degree. C. for 25-35 seconds followed by a water quench to
yield a controlled, fine, recrystallized grain size in the range
6-12 .mu.m. They were then cold rolled 50% to 0.050" gauge and
subjected to an aging anneal at 550-600.degree. C. for 3-4 hrs. The
alloys were then cold rolled 50% to 0.025" gauge and again given an
aging anneal 410-425.degree. C. for 2 hrs, followed by cold rolling
to 0.010" and relief annealing at 250-275.degree. C. for 2 hrs.
[0087] The properties at finished gauge, listed in Table 11, show a
better yield strength and conductivity combination was obtained
with either a Mg addition (J604 compared to J603) and/or a Zr
addition (J644 compared to J603).
[0088] Without the Mg addition, a Cr addition is not as effective
by itself (Compare the low strengths of J646 in Table 11 (column D)
with the higher strengths of J700 in Table 9). Note also from Table
11 how the Mg addition increases the yield strength (and tensile
strength) values over the Mg range: 0, 0.16, 0.25, 0.31 wt % Mg
addition to: 102 (110), 103 (112), 108 (116), 110 (118) ksi,
respectively, at nearly constant conductivity values of about 48%
IACS.
10TABLE 10 Alloys of Example 6 Alloy Identification Number Analyzed
composition, wt % J603 Cu-1.86 Ni-1.47 Ti-0.99 Fe J604 Cu-1.89
Ni-1.33 Ti-0.98 Fe-0.25 Mg J642 Cu-1.61 Ni-1.42 Ti-1.04 Fe-0.16 Mg
J643 Cu-1.61 Ni-1.40 Ti-1.02 Fe-0.31 Mg J644 Cu-1.53 Ni-1.37
Ti-0.91 Fe-0.19 Zr J646 Cu-1.61 Ni-1.43 Ti-0.98 Fe-0.52 Cr
[0089]
11TABLE 11 Properties for the relief annealed condition at 0.010"
gauge for alloys listed in Table 10 YS, ksi/UTS, ksi/Elong., %
Conductivity, % IACS Process: Alloy ID A B C D E F J603 88/97/4
91/100/4 101/110/4 102/110/3 103/112/3 103/111/3 62.4 56.0 53.4
48.1 50.3 46.9 J604 101/108/5 101/110/4 110/118/3 108/116/3
114/122/2 114/120/2 54.2 50.0 49.9 48.2 46.6 43.9 J642 93/101/3
94/104/4 105/112/3 103/112/3 106/114/3 106/113/3 60.1 56.0 53.9
51.3 53.8 50.6 J643 96/103/5 96/107/4 107/115/4 110/118/3 109/116/3
110/118/3 56.7 52.6 51.7 47.7 50.7 46.9 J644 87/98/4 97/107/4
105/114/3 107/116/4 108/117/3 108/116/3 64.7 61.1 56.8 50.3 53.4
47.6 J646 76/84/4 76/86/5 88/96/2 87/96/3 88/98/4 90/100/4 64.7
61.3 60.8 56.2 61.6 58.7
Example 7
[0090] This example illustrates how the composition and processing
influences yield strength and electrical conductivity. Alloys J694
and J709 having the compositions recited in Table 12 were processed
from 4".times.4".times.1.75" ingots by soaking for 3 hours at
950.degree. C. and hot rolling to 0.50 inch followed by a water
quench. After trimming and milling to remove oxides, the alloya
were cold rolled to 0.10 inch and solution heat treated at
1000.degree. C. for 35 seconds and water quenched. The alloys were
then cold rolled to 0.05 inch, solutionized at 950.degree. C. for
35 seconds and water quenched. Further processing is as in Table 13
with properties recited in Table 14.
12TABLE 12 Alloy Composition J694 Cu-1.78 Ni-1.34 Ti-0.98 Fe-0.24
Mg J709 Cu-0.93 Ni-0.90 Ti-1.05 Fe-0.24 Mg
[0091]
13TABLE 13 Process Process steps from 0.05 inch J1 Anneal at
565.degree. C. for 3 hours + cold roll to 0.025 inch + anneal at
410.degree. C. for 2 hours + cold roll to 0.015 inch + anneal at
250.degree. C. for 2 hours J2 Anneal at 565.degree. C. for 3 hours
+ cold roll to 0.025 inch + anneal at 410.degree. C. for 2 hours +
cold roll to 0.008 inch + anneal at 250.degree. C. for 2 hours
[0092]
14 Alloy J694 Alloy J709 Pro- YS TS Elong Cond YS TS Elong Cond
cess (ksi) (ksi) (%) (% IACS) (ksi) (ksi) (%) (% IACS) J1 117 122 1
42.8 111 115 1 42.8 J2 120 123 1 36.8 115 119 1 37.5
[0093] One or more embodiments of the present invention have been
describe above. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. Accordingly, other embodiments are within
the scope of the following claims.
* * * * *