U.S. patent application number 12/769118 was filed with the patent office on 2010-11-04 for copper alloy, method of producing the same, and copper tube.
This patent application is currently assigned to Golden Dragon Precise Copper Tube Group Inc.. Invention is credited to Zhenguo Feng, Honglin Guo, Junqi Li, Daixing Liu, Guowei Liu, Jinhao Zhao.
Application Number | 20100276039 12/769118 |
Document ID | / |
Family ID | 41173834 |
Filed Date | 2010-11-04 |
United States Patent
Application |
20100276039 |
Kind Code |
A1 |
Guo; Honglin ; et
al. |
November 4, 2010 |
COPPER ALLOY, METHOD OF PRODUCING THE SAME, AND COPPER TUBE
Abstract
Copper alloys, methods for producing copper alloys, and copper
tubes are provided. The copper alloys include an alpha solid
solution formed from phosphorous deoxidized copper and at least one
trace element comprising tin. The content of tin ranges from about
0.1% to about 2.0% by weight of the copper alloy. The trace element
can further include zinc in an amount from about 0.05% to about
1.0% by weight of the copper alloy. The copper alloys have an
increased tensile strength due to the strengthening effect by the
alpha solid solution formed by phosphorous deoxidized copper and
tin as the trace element, and accordingly a copper tube made from
the copper alloy has a significantly improved pressure
resistance.
Inventors: |
Guo; Honglin; (Xinxiang
City, CN) ; Feng; Zhenguo; (Xinxiang City, CN)
; Zhao; Jinhao; (Xinxiang City, CN) ; Liu;
Daixing; (Xinxiang City, CN) ; Liu; Guowei;
(Xinxiang City, CN) ; Li; Junqi; (Xinxiang City,
CN) |
Correspondence
Address: |
KING & SPALDING, LLP
1100 LOUISIANA ST., STE. 4000, ATTN.: IP Docketing
HOUSTON
TX
77002-5213
US
|
Assignee: |
Golden Dragon Precise Copper Tube
Group Inc.
Xinxiang City
CN
|
Family ID: |
41173834 |
Appl. No.: |
12/769118 |
Filed: |
April 28, 2010 |
Current U.S.
Class: |
148/553 ;
148/433 |
Current CPC
Class: |
F16L 9/02 20130101; C22F
1/08 20130101; C22C 1/002 20130101 |
Class at
Publication: |
148/553 ;
148/433 |
International
Class: |
C22F 1/08 20060101
C22F001/08; C22C 9/02 20060101 C22C009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 29, 2009 |
CN |
200910135785.2 |
Claims
1. A copper alloy comprising: an alpha solid solution formed from
phosphorus deoxidized copper and at least one trace element
comprising tin.
2. The copper alloy of claim 1, wherein the content of tin is from
about 0.1 percent to about 2.0 percent by weight of the copper
alloy.
3. The copper alloy of claim 2, wherein the at least one trace
element further comprises zinc, wherein the content of zinc is from
about 0.05 percent to about 1.0 percent by weight of the copper
alloy.
4. A method for producing a copper alloy, comprising: pre-heating
at least one trace element comprising tin to substantially remove
moisture present in the trace element; adding the trace element to
a molten solution of phosphorous deoxidized copper; and
homogenizing, casting, and cooling the molten solution comprising
the trace element to produce a copper alloy comprising an alpha
solid solution.
5. The method of claim 4, wherein the step of adding the trace
element to the molten solution of phosphorous deoxidized copper
comprises adding tin to the molten solution of phosphorous
deoxidized copper, wherein the content of tin is from about 0.1
percent to about 2.0 percent by weight of the alloy to be
produced.
6. The method of claim 5, wherein the at least one trace element
further comprises zinc, and wherein the step of adding the trace
elements to the molten solution of phosphorous deoxidized copper
further comprises adding zinc to the molten solution of phosphorous
deoxidized copper, wherein the content of zinc is from about 0.05
percent to about 1.0 percent by weight of the alloy to be
produced.
7. A copper tube comprising: a copper alloy comprising an alpha
solid solution formed from phosphorus deoxidized copper and at
least one trace element comprising tin.
8. The copper tube of claim 7, wherein the content of tin is from
about 0.1 percent to about 2.0 percent by weight of the copper
alloy.
9. The copper tube of claim 8, wherein the at least one trace
element further comprises zinc, wherein the content of zinc is from
about 0.05 percent to about 1.0 percent by weight of the copper
alloy.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. .sctn.119
to Chinese Patent Application No. 200910135785.2, titled "Copper
alloy, method of producing the same, and copper tube," filed Apr.
29, 2009. The complete disclosure of the foregoing priority
application is hereby fully incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates generally to a nonferrous
metal materials. More particularly, the present invention is
directed to copper alloys, methods of producing the copper alloys,
and copper tubes.
BACKGROUND
[0003] Copper tubes for air-conditioner cooling, or air-conditioner
tubes, are tubing materials that are specially used in heat
exchangers of cooling systems such as air-conditioners. Such tubing
materials generally include plain tubings and tubings having
various interior/exterior surface shapes, such as inner grooved
tubes and fin tubes.
[0004] Conventional copper tubes for air-conditioner cooling are
produced from phosphorous deoxidized copper. Phosphorous deoxidized
copper has a tensile strength that ranges from about 205 to about
255 megapascal (MPa), in soft state, at ambient temperature. The
phosphorous deoxidized copper has two specifications, including
U.S. C12000 (or China TP1) and U.S. C12200 (or China TP2). The
copper specification C12000 contains greater than or equal to 99.9
percent (%) of copper (Cu) and 0.004% to about 0.012% of phosphorus
(P); while the copper specification C12200 contains greater than or
equal to 99.9% of copper and 0.015% to about 0.040% of phosphorus.
In both of these specifications of phosphorous deoxidized copper,
the content of the element tin (Sn) is less than 0.005%, and the
content of zinc (Zn) is less than 0.001%.
[0005] The two specifications of phosphorous deoxidized copper
generally have appropriate toughness, welding behavior, strength,
compactness, and corrosion resistance for use in air-conditioner
cooling. However, there are a number of concerns with the use
phosphorous deoxidized copper. For example, conventional tubings
for air-conditioner cooling are lower in weight and have thin walls
so to save on material expenses. However, a thinner wall leads to
less pressure resistance, and thus these tubings have reduced
service life and reduced reliability. With the development and
application of environmentally friendly high-pressure refrigerants,
heat-transfer tubings generally require higher pressure resistance.
For example, a common refrigerant in home air-conditioners is
HCFC-22 (also known as R-22), which has been used as a refrigerant
for decades and is known to destroy the ozonosphere. In comparison,
novel, environmentally friendly refrigerants, such as R407c and
R410a, do not destroy the ozonosphere and have improved
refrigerating and heating efficiencies, which are recognized in the
international refrigeration industry as the optimal refrigerants
for home air-conditioners. Furthermore, these novel refrigerants
facilitate the miniaturization of air-conditioning systems, and
thus reduce the material expenses incurred by manufacturers.
However, the high pressure and the low pressure for the
environmentally friendly refrigerants R407c and R410a are 3.0 MPa
and 1.2 MPa respectively, which are about 1.5 times those pressures
for the traditional refrigerant R22. Another consideration when
designing air-conditioner tubes is related to the increasing
attention to environmental pollution being paid to refrigerants, as
humans increasingly focus on air pollution. Therefore, as more
users appeal to nonhazardous refrigerants, the use of common
refrigerants for air-conditioners is greatly limited. Refrigerants
having desired thermodynamics without producing air pollution are
urgently needed. Among varieties of refrigeration media in
consideration, liquid carbon dioxide (CO.sub.2) becomes the first
alternative refrigerant in vehicle air-conditioners due to its
unique ability to absorb a considerable amount of heat during
vaporization without polluting the atmosphere upon release of
carbon dioxide gas. However, one of the limitations for using
CO.sub.2 as the refrigerant in air-conditioners is that the
air-conditioning systems have to work at relatively high pressures,
at about five times the pressure in traditional systems, and thus,
challenge the pressure resistance of air-conditioner tubes.
[0006] Therefore, a need exists for air-conditioner tubes having
improved pressure resistance, and that meet the requirements for
the use in air-conditioners.
SUMMARY OF THE INVENTION
[0007] The air-conditioner tubes described herein have improved
pressure resistance over conventional tubings made from phosphorous
deoxidized copper.
[0008] In one aspect, a copper alloy can include alpha solid
solution formed by phosphorous deoxidized copper and at least one
trace element comprising tin. Preferably, the content of tin is
from about 0.1% to about 2.0% by weight of the copper alloy.
Preferably, the trace elements further comprise zinc, the content
of which is from about 0.05% to about 1.0% by weight of the copper
alloy. The copper alloys of the present invention have an increased
tensile strength over conventional copper alloys, due to the
strengthening effect by the alpha solid solution formed by
phosphorous deoxidized copper and the trace element tin
[0009] In another aspect, the present invention discloses a method
for producing a copper alloy of the present invention. The method
includes the steps of pre-heating at least one trace element
comprising tin to remove the moisture in the trace element, adding
the trace element into a molten solution of phosphorous deoxidized
copper, and homogenizing, casting, and cooling the solution
comprising the trace element, to produce a copper alloy comprising
alpha solid solution. Preferably, the step of adding the trace
element into the molten solution of phosphorous deoxidized copper
comprises adding tin, the amount of which is from about 0.1% to
about 2.0% by weight of the alloy to be produced, into the molten
solution of phosphorous deoxidized copper. Preferably, the trace
elements further comprise zinc, and the step of adding the trace
elements into the molten solution of phosphorous deoxidized copper
further comprises adding zinc, the amount of which is from about
0.05% to about 1.0% by weight of the alloy to be produced, into the
molten solution of phosphorous deoxidized copper.
[0010] In yet another aspect, tubes are constructed from a copper
alloy comprising alpha solid solution formed by phosphorous
deoxidized copper and at least one trace element comprising tin.
Preferably, the content of tin is from about 0.1% to about 2.0% by
weight of the copper alloy. Preferably, the trace elements further
comprise zinc, the content of which is from about 0.05% to about
1.0% by weight of the copper alloy. The copper tubes of the present
invention have a significantly improved pressure resistance over
conventional tubes for air-conditioners.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 depicts a method for producing a copper alloy,
according to an exemplary embodiment.
[0012] FIG. 2 depicts a method for producing a copper alloy,
according to another exemplary embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0013] A copper alloy described herein generally includes a trace
element added to a phosphorous deoxidized copper matrix in a ratio
such that the resulting alpha solid solution in the matrix has an
increased tensile strength due to strengthening effect by the solid
solution. Copper tubes for air-conditioners constructed from a
copper alloy of the present invention have a significantly improved
pressure resistance over conventional tubes for
air-conditioners.
[0014] In certain embodiments, the element tin (Sn) may be added to
phosphorous deoxidized copper to effectively improve the mechanical
properties of the copper alloy by means of solid solution
strengthening. In certain exemplary embodiments, the content of Sn
is from about 0.1% to about 2.0% by weight of the alloy.
Conventional alloys typically include a content of Sn that is less
than about 0.1% by weight of the alloy, and the solid solution
strengthening effect exhibits no significant advantage.
Furthermore, in the instance that the content of Sn is greater than
2.0% by weight of the alloy, the tensile strength of the resulting
alloy material is improved, however, the properties of the alloy
material severely impede the machining of the material, and
accordingly, would hinder tubing production.
[0015] In certain embodiments, the element zinc (Zn) may be added
to phosphorous deoxidized copper, which further improves the solid
solution strengthening, and has improved mechanical properties.
Moreover, the addition of Zn may reduce the size of crystal grains,
which may improve mechanical properties of the alloy material. In
certain exemplary embodiments, the content of Zn added may be about
1.0% by weight of the alloy, where the content of Sn is 0.1% by
weight of the alloy. In an alternative embodiment, the content of
Zn added may be 0.05% by weight of the alloy, where the content of
Sn is 2.0% by weight of the alloy. That is, the content of Zn added
may range from about 0.05% to about 1.0% by weight of the alloy,
where the content of Sn ranges from about 0.1% to about 2.0% by
weight of the alloy. In such circumstances, the addition of Sn in
combination with Zn improves properties of the alloy in comparison
with the addition of Sn only.
[0016] The copper alloys of the present invention demonstrate
improved properties over conventional copper alloys. To facilitate
a better understanding of the present invention, the following
examples of preferred embodiments are given. In no way should the
following examples be read to limit or define the scope of the
invention.
EXAMPLES
Example 1
[0017] A phosphorous deoxidized copper alloy comprises
0.1.about.2.0 weight-weight percentage (w/w %) of the element Sn,
which forms an alpha solid solution in the phosphorous deoxidized
copper as the matrix.
[0018] In view of the volume of the casting furnace, 0.1.about.2.0%
of the metal Sn as a solute was added into phosphorous deoxidized
copper as a matrix solvent, forming a solid solution of the solute
element in the matrix and thus a copper alloy. Accordingly the
increase of the deformation resistance between crystal grains
resulted in the effect of solid solution strengthening.
[0019] In order to further improve mechanical properties of the
copper alloy, phosphorous deoxidized copper may be selected as the
starting material to further control the contents of other
elements: less than 0.004% of sulfur (S), less than 0.004% of
oxygen (O), 0.01.about.0.05% of phosphorus (P), as well as copper
(Cu) and other impurities account for the remaining amount.
Furthermore, such impurity elements as iron (Fe), nickel (Ni),
chromium (Cr), silver (Ag), lead (Pb), aluminum (Al) and bismuth
(Bi) should be so controlled that the total content of the impurity
elements is no greater than 0.06% by weight.
[0020] It should be noted herein that the elements Zn and/or Sn
form a solid solution with copper in the copper alloy, and neither
Zn nor Sn is present in the form of its elementary substance.
However, the content of Sn or Zn can be determined by using proper
assays.
[0021] As tested, each of air-conditioner tubings made from the
copper alloy of the present invention has the tensile strength of
greater than 260 MPa, specific elongation of greater than 40%, and
a mean crystal grain size of about 0.015 to about 0.035 mm, while
the tubings made from phosphorous deoxidized copper has the tensile
strength of about 230 to about 240 MPa. As confirmed with a number
of assays, the tubings made from the copper alloy of the present
invention have significantly improved pressure resistance, in
comparison with the tubings of identical specifications from
phosphorous deoxidized copper. Furthermore, in comparison with the
tubings constructed from phosphorous deoxidized copper, the wall
thickness of tubings made from the copper alloy of the present
invention can be reduced by at least 15%, which meets normal
operation pressure requirements, and significantly saves the cost
of material.
[0022] A formulation of a copper alloy having 0.1.about.2.0% of Sn,
less than 0.004% of S, less than 0.004% of O, 0.01.about.0.05% of
P, as well as Cu and impurities (for the remaining), was used to
produce copper alloy tubes, wherein such impurity elements as Fe,
Ni, Cr, Ag, Pb, Al and Bi were so controlled that the total content
of the impurity elements is less than 0.06% by weight. The samples
of copper alloy tubings in soft state (upon annealing) were tested
at ambient temperature (about 20.degree. C.) in terms of tensile
strength, which is listed in Table 1 below.
TABLE-US-00001 TABLE 1 Sn (w/w %) Tensile strength (MPa) 0.1% 260
0.45% 270 2.0% 290
[0023] As shown in Table 1, all of the samples of copper alloy
tubings in soft state (upon annealing) tested at ambient
temperature (about 20.degree. C.) have a tensile strength of
greater than 260 MPa, while the tubings of phosphorous deoxidized
copper have a tensile strength of 205.about.255 MPa. Accordingly,
as the copper alloy tubings have improved tensile strength, they
have correspondingly improved pressure resistance.
[0024] Parameters of the tubings made from the present copper alloy
comprising Sn 0.1.about.2.0% and phosphorous deoxidized copper
respectively, which have a diameter of 7 mm and wall thickness of
0.24 mm are listed in Table 2 below.
TABLE-US-00002 TABLE 2 Phosphorous deoxidized Copper alloy copper
Burst Burst Wall Burst Tensile pressure/ Burst Tensile pressure/
Diameter thickness pressure strength tensile pressure strength
tensile (mm) (mm) (MPa) (MPa) strength (MPa) (MPa) strength 7.03
0.24 17.4 270 0.0644 14.2 235 0.0604 7.01 0.24 17.2 270 0.0637 14.3
238 0.0601 7.03 0.24 17.3 276 0.0628 14.4 240 0.0598 7.02 0.24 17.4
272 0.0639 14.3 240 0.0596 7.02 0.24 17.6 273 0.0643 14.2 236
0.0602 7.03 0.24 17.7 275 0.0643 14.5 237 0.0611 7.01 0.24 18.1 281
0.0645 14.5 237 0.0612 7.01 0.24 17.2 269 0.0641 14.5 238 0.0611
7.03 0.24 17.2 268 0.0642 14.3 235 0.0610 7.03 0.24 17.3 272 0.0635
14.1 235 0.0598 7.02 0.24 17.2 270 0.0638 14.1 236 0.0599 7.02 0.24
17.7 279 0.0636 14.2 236 0.0602 7.01 0.24 17.5 276 0.0635 13.9 232
0.0601 7.01 0.24 17.0 265 0.0641 14.1 230 0.0611 7.03 0.24 17.2 269
0.0641 14.1 231 0.0612
[0025] As used herein, the term "burst pressure/tensile strength"
refers to the destruction force tolerable by the tubing when the
tensile strengths of the tubings are the same. A high burst
pressure indicates an enhanced pressure resistance. As seen clearly
in Table 2, the copper tubings made from the present copper alloy
have improved mechanical properties in comparison with those made
from phosphorous deoxidized copper.
[0026] With respect to tensile strength, the copper alloy tubings
of the present invention are significantly superior to those of
phosphorous deoxidized copper in the same specification. With
respect to burst pressure, the copper alloy tubings of the present
invention are significantly superior to those of phosphorous
deoxidized copper in the same specification. With respect to burst
pressure/tensile strength, the copper alloy tubings of the present
invention can tolerate a significantly higher destruction force
than the tubings of phosphorous deoxidized copper in the same
specification, if their tensile strengths are the same. Therefore,
the copper alloy tubings exhibit better pressure resistance than
the latter in the same specification.
Example 2
[0027] A phosphorous deoxidized copper alloy comprises
0.1.about.2.0w/w % of the element Sn, 0.05.about.1.0% of the
element Zn, wherein the elements Sn and Zn form alpha solid
solution in the phosphorous deoxidized copper as the matrix.
[0028] In order to further improve mechanical properties of the
copper alloy, the contents of other elements may be controlled:
less than 0.004% of S, less than 0.004% of O, 0.01.about.0.05% of
P, as well as Cu and other impurities account for the remaining
amount. Furthermore, such impurity elements as Fe, Ni, Cr, Ag, Pb,
Al and Bi are controlled that the total content of the impurity
elements is no greater than 0.06% by weight.
[0029] A formulation of a copper alloy having 0.1.about.2.0% of Sn,
0.05.about.1.0% of Zn, less than 0.004% of S, less than 0.004% of
O, 0.01.about.0.05% of P, as well as Cu and impurities (for the
remaining), was used to produce copper alloy tubes having a
diameter of 7 mm, wherein such impurity elements as Fe, Ni, Cr, Ag,
Pb, Al and Bi were controlled such that the total content of the
impurity elements was less than 0.06% by weight. The samples of
copper alloy tubings in soft state (upon annealing) were tested at
ambient temperature (about 20.degree. C.) in terms of tensile
strength, which is listed in Table 3 below.
TABLE-US-00003 TABLE 3 Sn (w/w) Zn (w/w) Tensile strength (MPa)
0.1% 1.0% 265 0.45% 0.4% 275 2.0% 0.05% 295
[0030] As shown in Table 3, all of the samples of copper alloy
tubings in soft state (upon annealing) tested at ambient
temperature (about 20.degree. C.) have a tensile strength of
greater than 265 MPa, while the tubings of phosphorous deoxidized
copper have a tensile strength of 205.about.255 MPa. Accordingly,
as the copper alloy tubings have improved tensile strength, they
have correspondingly improved pressure resistance.
[0031] The invention may be better understood by reading the
following description of non-limitative, exemplary embodiments with
reference to the attached drawings wherein like parts of each of
the figures are identified by the same reference characters.
[0032] With reference to FIG. 1, the present invention provides a
method for producing a copper alloy. In step 101, at least one
trace element comprising tin is preheated to substantially remove
any moisture in the trace element. Step 101 is followed by step
102, in which the trace element is added to a molten solution of
phosphorous deoxidized copper. After step 102, in step 103, the
solution comprising the trace element is homogenized, casted, and
cooled to produce a copper alloy comprising an alpha solid
solution.
[0033] In certain exemplary embodiments, the content of tin ranges
from about 0.1% to about 2.0% by weight of the copper alloy. If the
content of Sn is less than 0.1% by weight of the alloy, the solid
solution strengthening effect exhibits no significant advantage in
comparison with conventional alloys. Furthermore, in the instance
that the content of Sn is greater than 2.0% by weight of the alloy,
the tensile strength of the resulting alloy material is improved,
however, the properties of the alloy material severely impede the
machining of the material, and accordingly, would hinder tubing
production.
[0034] In certain embodiments, the element zinc (Zn) may be added
to a molten fluid of copper, which further improves the solid
solution strengthening, and has improved mechanical properties.
Moreover, the addition of Zn may reduce the size of crystal grains,
which may improve mechanical properties of the alloy material. In
certain exemplary embodiments, the content of Zn ranges from about
0.05% to about 1.0% by weight of alloy. In certain exemplary
embodiments, the content of Zn added may be about 1.0% by weight of
the alloy, where the content of Sn is 0.1% by weight of the alloy.
In an alternative embodiment, the content of Zn added may be 0.05%
by weight of the alloy, where the content of Sn is 2.0% by weight
of the alloy. That is, the content of Zn added may range from about
0.05% to about 1.0% by weight of the alloy, where the content of Sn
ranges from about 0.1% to about 2.0% by weight of the alloy. In
such circumstances, the addition of Sn in combination with Zn
improves properties of the alloy in comparison with the addition of
Sn only.
[0035] In order to further improve mechanical properties of the
copper alloy, phosphorous deoxidized copper may be selected as the
starting material to further control the contents of other
elements: less than 0.004% of sulfur (S), less than 0.004% of
oxygen (O), 0.01-0.05% of phosphorus (P), as well as copper (Cu)
and other impurities account for the remaining amount. Furthermore,
such impurity elements as iron (Fe), nickel (Ni), chromium (Cr),
silver (Ag), lead (Pb), aluminum (Al) and bismuth (Bi) should be so
controlled that the total content of the impurity elements is no
greater than 0.06% by weight. In certain exemplary embodiments, the
copper alloy of the present invention includes 0.45% by weight of
Sn, less than 0.004% of S, less than 0.004% of O, 0.01.about.0.05%
of P, and the total content of the impurity elements is less than
0.06% by weight.
[0036] With reference to FIG. 2, the present invention provides
another method for producing a copper alloy. In step 201, the trace
element of tin is pre-heated to substantially remove any moisture.
In step 202, the amount by weight of the elements tin or both tin
and zinc is determined, as well as the weight of phosphorous
deoxidized copper. For example, if the casting oven has a volume of
V, then the copper alloy to be produced is accordingly determined
to have a weight of M. If tin is only added to the alloy to be
produced, in which the content of tin is 0.45% by weight, then
M.times.0.45% of tin is added into the casting oven, while the
weight of phosphorous deoxidized copper is M-M.times.0.45%.
[0037] Step 202 is followed by step 203, in which tin or both tin
and zinc is/are added in the predetermined amount in a single batch
into the casting oven having molten phosphorous deoxidized copper
in the predetermined amount. Since the trace elements to be added
(Sn or Zn) have a low density and a low melting temperature, adding
the tin or both tin and zinc in a single batch allows the elements
to readily melt, depending on the shape and size of Sn and
optionally Zn. In step 204, the trace elements of tin and optional
zinc in the molten copper liquid are agitated and homogenized.
Thereafter, in step 205, the copper alloy is casted into hollow or
solid billet by means of horizontal continuous casting. Finally, in
step 206, the hollow or solid billet is cooled to ambient
temperature.
[0038] In the process of copper casting, the copper alloy is formed
by adding the solute metal of Sn to phosphorous deoxidized copper
as the matrix solvent, and the effect of solid solution
strengthening is achieved due to the increased resistance to
deformation between crystal grains. The tubes of copper alloy are
constructed from the copper alloy, which is a finished product in
soft state by the treatment of casting, rolling, elongating and
annealing. As tested, the resulting tubes have a tensile strength
of greater than about 260 MPa, specific elongation of greater than
40%, and mean crystal grain size of about 0.015 to about 0.035 mm.
Moreover, under similar conditions, the tubings of the present
invention have a significant higher burst pressure than that of
conventional tubings from phosphorous deoxidized copper.
[0039] In certain embodiments, the present invention provides a
copper alloy tube, wherein the copper alloy comprises alpha solid
solution formed by phosphorous deoxidized copper and at least one
trace element comprising tin. In certain exemplary embodiments, the
content of tin is about 0.1% to about 2.0% by weight of the copper
alloy. In certain exemplary embodiments, the trace element further
comprises zinc, the content of which is about 0.05% to about 1.0%
by weight of the copper alloy. The principles, methods and
particular experimental data have been described in the above
examples, and thereby are not described again for conciseness.
[0040] In the process of phosphorous deoxidized copper casting, the
copper microalloy is formed by adding the solute metal of Sn and
optionally Zn, in proper amounts in view of the volume of casting
oven, to phosphorous deoxidized copper as the matrix solvent, and
then forming a solid solution of the solute element in the matrix.
The effect of solid solution strengthening is achieved due to
increased resistance to deformation between crystal grains, thereby
the copper alloy tubes of the present invention have significantly
improved pressure resistance.
[0041] A copper alloy, a method for producing the copper alloy, and
a copper tube derived therefrom are described above in detail.
Therefore, the present invention is well adapted to attain the ends
and advantages mentioned as well as those that are inherent
therein. The particular embodiments disclosed above are
illustrative only, as the present invention may be modified and
practiced in different but equivalent manners apparent to those
having ordinary skill in the art having the benefit of the
teachings herein. While numerous changes may be made by those
having ordinary skill in the art, such changes are encompassed
within the spirit of this invention as defined by the appended
claims. It is therefore evident that the particular illustrative
embodiments disclosed above may be altered or modified and all such
variations are considered within the scope and spirit of the
present invention.
* * * * *