U.S. patent application number 16/321756 was filed with the patent office on 2019-05-30 for softening resistant copper alloy, preparation method, and application thereof.
The applicant listed for this patent is Ningbo Powerway Alloy Material Co., Ltd., Ningbo Powerway Alloy Plate & Strip Co., Ltd.. Invention is credited to Renchang Hu, Juan Li, Weiwei Li, Yongjun Pei, Yubo Song, Mengtao Tian, Jijun Wang, Er Zhang.
Application Number | 20190161831 16/321756 |
Document ID | / |
Family ID | 57858375 |
Filed Date | 2019-05-30 |
United States Patent
Application |
20190161831 |
Kind Code |
A1 |
Pei; Yongjun ; et
al. |
May 30, 2019 |
Softening Resistant Copper Alloy, Preparation Method, and
Application Thereof
Abstract
A softening resistant copper alloy, a preparation method, and an
application thereof, the softening-resistant copper alloy,
comprising 0.1%-1.0 wt % Cr, 0.01%-0.2 wt % Zr, 0.01%-0.10 wt % Si,
and .ltoreq.0.10 wt % Fe, and with the remaining of copper and
inevitable impurities, wherein the microstructure of the copper
alloy contains comprises: an elemental Cr phase, a Cu.sub.5Zr
phase, and a Cr.sub.3Si phase. In the copper alloy of the present
invention, the high-temperature softening resistance effect of the
material is improved by adding a proper amount of Si to form a
compound Cr.sub.3Si, and the strength and the high-temperature
softening resistance of the material are further improved by
strengthening the copper alloy matrix by the elemental Cr phase and
the Cu.sub.5Zr phase, using the synergistic effect of the
Cr.sub.3Si phase and the elemental Cr phase and by controlling the
content of the impurity Fe. The copper alloy can be applied to
contact lines and welding materials to prolong the service life of
the materials.
Inventors: |
Pei; Yongjun; (Ningbo,
CN) ; Wang; Jijun; (Ningbo, CN) ; Zhang;
Er; (Ningbo, CN) ; Song; Yubo; (Ningbo,
CN) ; Li; Juan; (Ningbo, CN) ; Li; Weiwei;
(Ningbo, CN) ; Hu; Renchang; (Ningbo, CN) ;
Tian; Mengtao; (Ningbo, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ningbo Powerway Alloy Plate & Strip Co., Ltd.
Ningbo Powerway Alloy Material Co., Ltd. |
Ningbo
Ningbo |
|
CN
CN |
|
|
Family ID: |
57858375 |
Appl. No.: |
16/321756 |
Filed: |
August 18, 2017 |
PCT Filed: |
August 18, 2017 |
PCT NO: |
PCT/CN2017/000536 |
371 Date: |
January 29, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22C 9/00 20130101; C22C
2202/00 20130101; C22F 1/08 20130101 |
International
Class: |
C22C 9/00 20060101
C22C009/00; C22F 1/08 20060101 C22F001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 9, 2016 |
CN |
201610813189.5 |
Claims
1. A softening-resistant copper alloy, comprising: 0.1%-1.0 wt %
Cr, 0.01% -0.2 wt % Zr, 0.01%-0.10 wt % Si, and .ltoreq.0.10 wt %
Fe, and with the remaining of copper and inevitable impurities,
wherein the microstructure of the copper alloy comprises: an
elemental Cr phase, a Cu.sub.5Zr phase, and a Cr.sub.3Si phase.
2. The copper alloy of claim 1, wherein the elemental Cr phase and
the Cr.sub.3Si phase satisfy the following relationship: if the
weight of the elemental Cr phase is X and the weight of the
Cr.sub.3Si phase is Y, then 0<X/Y<20.
3. The copper alloy of claim 1, further comprising: 0.0001%-0.10 wt
% Mg.
4. The copper alloy of claim 1, further comprising: 0.01% to 2.5 wt
% of any one or more of Co, Zn, Mn, Sn and Nb, and their total
amount does not exceed 3.5 wt % of the copper alloy.
5. The copper alloy of claim 1, wherein the softening temperature
of the copper alloy is greater than or equal to 580.degree. C.
6. A method for preparing the copper alloy of claim 1, the method
comprising: alloying and refining--casting into an ingot--ingot
sawing, heating and extruding--solid solution heat
treatment--stretching and drawing--aging heat
treatment--straightening and finalizing; wherein the casting
temperature for the alloying treatment and the covered refining is
1150.degree. C. to 1350.degree. C.; the temperature for the hot
extrusion is 850.degree. C. to 950.degree. C.; the temperature for
the solid solution treatment is 850.degree. C. to 1000.degree. C.;
the cooling medium is water, and the cooling rate is 10.degree.
C./min to 150.degree. C./s; the machining rate of the cold
stretching and drawing is 20% to 60%; the temperature for the aging
heat treatment is 420.degree. C. to 520.degree. C.; and, the copper
alloy is insulated for 2 h to 4 h.
7. The copper alloy of claim 1, the method comprising using the
softening-resistant copper alloy in contact lines and welding
materials.
Description
RELATED APPLICATIONS
[0001] This application is a national phase entrance of and claims
benefit to PCT Application for a softening-resistant copper alloy,
a preparation method thereof and applications thereof,
PCT/CN2017/000536, filed on Aug. 18, 2017, which claims benefit to
Chinese Patent Applications 201610813189.5, filed on Sep. 9, 2016.
The specifications of both applications are incorporated here by
this reference.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of copper alloy
manufacturing, and in particular to a softening-resistant copper
alloy, a preparation method thereof and applications thereof,
belonging to the technical field of novel alloy materials.
DESCRIPTION OF THE PRIOR ART
[0003] Welding is a manufacturing technology that joins metals or
other materials by heating, at high-temperature or under
high-pressure.
[0004] At present, there are mainly three methods for joining
materials: fusion welding, pressure welding and braze welding.
During the welding process, a workpiece and the solder are molten
to form a molten area, and the molten pool is cooled and solidified
to form a connection between the materials. During this process, it
is usually necessary to apply a pressure. There are a variety of
sources of energy for welding, including gas flame, electric arc,
laser, electron beams, friction, ultrasonic waves and the like.
Before the end of the 19.sup.th century, the only welding process
was metal forging already used by the blacksmith for hundreds of
years. The earliest modern welding techniques appeared at the end
of the 19.sup.th century, first arc welding and oxygen-fuel welding
and then resistance welding. In the early 20.sup.th century, as the
first and second world wars happened, the demand for cheap and
reliable connection methods for military materials was extremely
high, so that the development of the welding techniques was also
facilitated. With the extensive use of welding robots in industrial
applications, researchers are still studying the nature of welding
and continuing to develop new welding methods to further improve
the welding quality.
[0005] Throughout the development of modern welding techniques and
equipment, the automation of welding equipment and the improvement
of production efficiency are major driving forces for the
development of welding techniques. Since copper alloys are good in
strength and electrical performance, many consumables in the
welding equipment use copper and its alloys, for example, electrode
caps in resistance welding, conductive nozzles in braze welding and
the like. With the use of modern automatic equipment, particularly
welding robots, the requirements on copper alloys used for
conductive nozzles, electrode caps and the like, particularly their
ability to resist against high-temperature softening, are
increasing. During the welding process, due to the need for
heating, high temperature or high pressure, the actual copper alloy
consumables are often used at a very high temperature, so the
requirements on the copper alloys are also increasing. In other
fields, there are also examples of using materials in a
high-temperature environment. For example, electrified railway
contact lines are also to be used for a long period of time at a
relatively high temperature. Therefore, it is urgent to develop a
copper alloy with better high-temperature softening resistance.
[0006] At present, the actually popularized products, such as
conductive nozzles for welding equipment, electrode caps and
electrified railway contact lines, mostly use conventional copper
chromium zirconium alloy (e.g., American Standard C18150) which has
been widely applied in the above fields due to its excellent
strength and electrical conductivity. However, with the gradual
increase of the level of mechanical automation, a strategy of
replacing manpower with machines basically comes into use in
welding and other industries, in order to improve the production
efficiency. This change will present new requirements on the raw
material performances of parts, among which high-temperature
softening resistance comes first. This is because the wear of the
parts will be less if the high-temperature softening resistance is
better. Accordingly, the service life of the parts is prolonged and
the precision during the welding process is also improved. At
present, the conventional copper chromium zirconium alloy (e.g.,
American Standard C18150) has a high-temperature softening
resistance that a hardness loss value is above 15% below
580.degree. C. This already cannot meet the development
requirements of the related industries. Therefore, improving the
high-temperature softening resistance of materials becomes an
urgent need at present.
SUMMARY OF THE INVENTION
[0007] An objective of the present invention is to provide a copper
alloy with better high-temperature softening resistance, in order
to solve the problem that the high-temperature softening resistance
of the existing copper chromium zirconium alloy is to be
improved.
[0008] To solve the technical problem, the softening-resistant
copper alloy, comprises: 0.1%-1.0 wt % Cr, 0.01% -0.2 wt % Zr,
0.01%-0.10 wt % Si, and .ltoreq.0.10 wt % Fe, and with the
remaining of copper and inevitable impurities, wherein the
microstructure of the copper alloy comprises: an elemental Cr
phase, a Cu.sub.5Zr phase, and a Cr.sub.3Si phase. In the copper
alloy of the present invention, the high-temperature softening
resistance effect of the material is improved by adding a proper
amount of Si to form a compound Cr.sub.3Si, and the strength and
the high-temperature softening resistance of the material are
further improved by strengthening the copper alloy matrix by the
elemental Cr phase and the Cu.sub.5Zr phase, using the synergistic
effect of the Cr.sub.3Si phase and the elemental Cr phase and by
controlling the content of the impurity Fe.
[0009] The effects of the alloy elements and the related
precipitated phases in the copper will be described below.
[0010] The solid solubility of chromium in copper at the normal
temperature is very small (less than 0.5%), but the solid
solubility of chromium in copper at a high temperature is
relatively high (up to 0.65%). Therefore, chromium is able to
realize precipitation strengthening and used as a main
strengthening element in the copper alloy of the present invention.
In the copper alloy, dispersion strengthening phase particles of
the elemental Cr can be obtained by heat treatment, so the copper
matrix is strengthened. While strengthening the copper matrix, Cr
will also form a compound Cr.sub.3Si with Si solid-dissolved in the
copper matrix. Researches have indicated that the compound
Cr.sub.3Si is a compound phase that is stable at a high temperature
and will not be dissolved even at a high temperature of 800.degree.
C., so that the high-temperature softening resistance is very high.
The content of chromium in the copper alloy of the present
invention is 0.1% to 1.0%. If the content of chromium is less than
this range, Cr and Si are difficult to form Cr.sub.3Si or can form
a small amount of Cr.sub.3Si so that the desired effect cannot be
achieved; however, if the content of chromium is greater than this
range, chromium will be largely precipitated to form a
strengthening phase, so that the chromium will be largely
accumulated at the crystal boundary and the plasticity of the
material is damaged.
[0011] Zirconium has a certain solubility in the copper alloy. By
adding zirconium, the recrystallization temperature of the copper
matrix can be increased and the high-temperature softening
resistance of the copper alloy can be thus improved. Moreover,
zirconium and copper will form an intermediate compound Cu.sub.5Zr,
strengthening the copper matrix and also improving the electrical
performance of the copper alloy. The content of zirconium in the
copper alloy of the present invention is 0.01% to 0.2%. If the
content of zirconium is less than this range, the desired effect
cannot be achieved; however, if the content of zirconium is greater
than this range, although the alloy can be strengthened, the
electrical conductivity of the alloy will be greatly reduced and
the overall performance of the alloy will be influenced.
[0012] Silicon has a certain solid solubility in copper. Silicon
can strengthen the copper alloy matrix, but will greatly influence
the electrical conductivity of copper and will greatly reduce the
electrical conductivity of the copper alloy. However, when there is
a proper amount of chromium in the copper alloy, silicon and
chromium can form a Cr.sub.3Si phase compound. Since Cr.sub.3Si is
a precipitated phase, the electrical conductivity of the material
can be greatly improved after Cr.sub.3Si is precipitated, so that
the overall performance of the copper alloy is positively
influenced. The content of silicon in the copper alloy of the
present invention is 0.01% to 0.1%. If the content of silicon is
less than this range, the Cr.sub.3Si phase formed in the copper
alloy is not enough to achieve the desired effect; however, if the
content of silicon is greater than this range, although sufficient
Cr.sub.3Si phase can be formed, the precipitation of Cr will be
greatly reduced and the overall performance of the alloy will thus
be influenced.
[0013] In the present invention, Fe is controlled as an impurity
element. A small amount of Fe facilitates the improvement of
strength, but a too high content of Fe will affect the electrical
conductivity. Therefore, in the present invention, the content of
Fe is controlled below 0.01 wt %.
[0014] The elemental Cr phase, the Cu.sub.5Zr phase and the
Cr.sub.3Si phase in the microstructure of the copper alloy of the
present invention have the following effects.
[0015] As a primary phase of alloy, the Cr.sub.3Si phase is
generated during the liquid state and crystallization process of
the alloy, is stable in both structure and performance at a high
temperature, and will not be dissolved at 800.degree. C. while
still maintaining its original structure. Accordingly, the
high-temperature softening resistance of the alloy can be greatly
improved. As one of main precipitation strengthening phases in the
copper alloy of the present invention, the Cu.sub.5Zr phase is
completely dissolved in the copper matrix to form a supersaturated
solid solution after solid solution treatment on the alloy, then
precipitated out of the copper matrix during the subsequent aging
process and dispersedly distributed in the alloy. After the
Cu.sub.5Zr phase is precipitated, a pinning effect on the
dislocation is achieved, so that the strength and hardness of the
copper matrix are improved. Meanwhile, due to the precipitation of
the Cu.sub.5Zr phase, the copper matrix becomes pure, the
inhibition of electrons is reduced, the electrical resistivity is
reduced, and the electrical conductivity is thus greatly improved.
Another strengthening phase in the copper alloy of the present
invention is the elemental Cr phase. Similarly to the generation
principle of the Cu.sub.5Zr phase, the elemental Cr phase is also
generated during the heat treatment of the alloy. The elemental Cr
phase is completely dissolved in the copper matrix to form a
supersaturated solid solution after the solid solution treatment,
then precipitated out of the copper matrix during the subsequent
aging process and dispersedly distributed in the alloy. As the most
important strengthening phase in the alloy of the present
invention, the elemental Cr phase plays a crucial role in the
improvement of the strength of the alloy.
[0016] The three main strengthening phases in the alloy of the
present invention exist independently and have a certain
dependence. The addition of a suitable proportion of alloy elements
to form a rational proportion of phases is very important for the
performance of the alloy. The elemental Cr phase, as the main
strengthening phase in the alloy, plays a leading role in the
strengthening of the alloy; the Cr.sub.3Si phase, as a
high-temperature phase, plays a leading role in the
high-temperature softening resistance of the alloy; and, the
Cu.sub.5Zr phase, as another moderate strengthening phase, can
strengthen the alloy and can also increase nucleating particles,
refine the elemental Cr phase and the Cr.sub.3Si phase and allow
the elemental Cr phase and the Cr.sub.3Si phase to be dispersedly
distributed, so that both the strength and the high-temperature
softening resistance are further improved.
[0017] Preferably, the elemental Cr phase and the Cr.sub.3Si phase
satisfy the following relationship:
[0018] if the weight of the elemental Cr phase is X and the weight
of the Cr.sub.3Si phase is Y, then 0<X/Y<20.
[0019] When the strengthening phases satisfy this ratio, both the
high-temperature softening resistance and the strength of the
copper alloy will be greatly improved. When the ratio of the
strengthening phases is greater than 20, the amount of the
Cr.sub.3Si phase in the alloy is very small. As a result, the
high-temperature softening resistance of the alloy cannot satisfy
the requirements.
[0020] Preferably, the copper alloy further comprises: 0.0001%-0.10
wt % Mg. By providing magnesium in this proportion, magnesium can
be dissolved in the copper matrix to strengthen the copper alloy,
with little influence on the electrical conductivity of the copper
alloy; and meanwhile, oxygen in the copper alloy can be effectively
eliminated, so that the content of oxygen in the copper alloy is
reduced and the quality of the material is improved.
[0021] Preferably, the copper alloy further comprises: 0.01% to 2.5
wt % of any one or more of Co, Zn, Mn, Sn and Nb, and their total
amount does not exceed 3.5 wt % of the copper alloy. By adding the
above alloy elements in the copper alloy, solid solution
strengthening can be realized, the recrystallization temperature of
the material is increased, and the softening temperature of the
material is further increased. However, the amount of addition of
the above alloy elements should not be too large, otherwise the
electrical conductivity of the material will be greatly
reduced.
[0022] Preferably, the softening temperature of the copper alloy is
greater than or equal to 580.degree. C.When the softening
temperature of the copper alloy is greater than or equal to
580.degree. C., the demands for various welding processes by the
material can be greatly increased, and the service life of the
welding material is prolonged.
[0023] The softening temperature of the copper alloy is determined
by tests. Generally, when the material is kept at a certain
temperature for 2 hours and then cooled in water, the hardness of
the treated material is tested. If the hardness loss of the treated
material is within 15%, it is considered that the material is not
softened at this temperature; or otherwise, it is considered that
the material is softened. The softening temperature of the
conventional copper chromium zirconium alloy is about 550.degree.
C. If the conventional copper chromium zirconium alloy is kept at
550.degree. C. for 2 hours and then cooled in water, the hardness
loss of the treated material is about 13% to 15%; and, if the
conventional copper chromium zirconium alloy is kept at 580.degree.
C., the hardness loss is far greater than 15%.Therefore, the
softening temperature of the conventional copper chromium zirconium
alloy is 550.degree. C. However, for the copper alloy of the
present invention, under the above experimental conditions, the
hardness loss of the material at 550.degree. C. is 4% to 8%, and
the hardness loss of the material at 550.degree. C. does not exceed
10%. Therefore, the softening temperature of the copper alloy of
the present invention is greater than or equal to 580.degree.
C.
[0024] The present invention further discloses a method for
preparing copper alloy, the method comprising: alloying and
refining casting into an ingot--ingot sawing, heating and
extruding--solid solution heat treatment--stretching and
drawing--aging heat treatment--straightening and finalizing;
[0025] wherein the casting temperature for the alloying treatment
and the covered refining is 1150.degree. C. to 1350.degree. C.; the
temperature for the hot extrusion is 850.degree. C. to 950.degree.
C.; the temperature for the solid solution treatment is 850.degree.
C. to 1000.degree. C.; the cooling medium is water, and the cooling
rate is 10.degree. C./min to 150.degree. C./s; the machining rate
of the cold stretching and drawing is 20% to 60%; the temperature
for the aging heat treatment is 420.degree. C. to 520.degree. C.;
and the copper alloy is insulated for 2 h to 4 h. In the material
produced by this production process, the elemental Cr phase, the
Cu.sub.5Zr phase and the Cr.sub.3Si phase are rational in size and
more dispersive in distribution, so that various performances of
the copper alloy of the present invention are improved.
[0026] The present invention discloses a method of using the copper
alloy, the method comprising using the softening-resistant copper
alloy in contact lines and welding materials.
[0027] Compared with the prior art, the present invention has the
following advantages:
[0028] 1. In the copper alloy of the present invention, the
high-temperature softening resistance effect of the material is
improved by adding a proper amount of Si to form a compound
Cr.sub.3Si, and the strength and the high-temperature softening
resistance of the material are further improved by strengthening
the copper alloy matrix by the elemental Cr phase and the
Cu.sub.5Zr phase, using the synergistic effect of the Cr.sub.3Si
phase and the elemental Cr phase and by controlling the content of
the impurity Fe.
[0029] 2. Since the softening temperature of the copper alloy of
the present invention is greater than or equal to 580.degree. C.,
the requirements on various performances of the copper alloy in the
fields of welding and contact lines are better satisfied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0030] To enable a further understanding of the present invention
content of the invention herein, refer to the detailed description
of the invention and the accompanying drawings below:
[0031] To avoid repetition, the technical parameters involved in
the specific implementations will be uniformly described below, and
will not be repeated in embodiments.
[0032] wt %: weight percentage.
[0033] % IACS: used for representing the electrical conductivity of
a metal or alloy (reference to the standard annealed pure
copper).The electrical conductivity of the standard annealed pure
copper is generally defined as 100% IACS, i.e., 5.80E+7(1/.OMEGA.m)
or 58(m/.OMEGA.mm.sup.2).The value is the ratio of the resistivity
(in volume or mass) specified by the International Annealed Copper
Standard to the resistivity of the sample in the same unit
multiplied by 100.
[0034] HR: Rockwell hardness.
[0035] Rem.: remaining amount.
Embodiments 1-20
TABLE-US-00001 [0036] TABLE 1 Composition instances of components
of the softening-resistant copper alloy of the present invention
(wt %): Component Chemical component (wt %) Other Embodiment Cr Zr
Si Mg Fe elements Cu Embodiment 1 0.10 0.010 0.015 -- -- -- Rem.
Embodiment 2 0.187 0.016 0.010 0.018 0.027 -- Rem. Embodiment 3
0.192 0.189 0.027 0.014 0.017 -- Rem. Embodiment 4 0.24 0.027 0.022
0.035 0.009 -- Rem. Embodiment 5 0.297 0.029 0.026 0.043 0.028 --
Rem. Embodiment 6 0.367 0.046 0.026 0.016 0.009 -- Rem. Embodiment
7 0.43 0.048 0.035 0.006 0.042 -- Rem. Embodiment 8 0.46 0.059
0.038 0.068 0.021 -- Rem. Embodiment 9 0.51 0.06 0.065 0.072 0.057
-- Rem. Embodiment 0.59 0.072 0.046 0.088 0.068 -- Rem. 10
Embodiment 0.64 0.079 0.028 0.096 0.079 -- Rem. 11 Embodiment 0.68
0.085 0.067 0.005 0.100 -- Rem. 12 Embodiment 0.75 0.091 0.096
0.052 0.062 -- Rem. 13 Embodiment 0.81 0.115 0.062 0.002 0.004 --
Rem. 14 Embodiment 0.84 0.127 0.042 0.017 0.037 -- Rem. 15
Embodiment 0.89 0.149 0.019 0.002 0.023 -- Rem. 16 Embodiment 0.89
0.147 0.031 0.021 Nb: 0.031 Rem. 17 Embodiment 0.95 0.176 0.079
0.021 0.023 Nb: 0.097 Rem. 18 Embodiment 0.87 0.177 0.082 0.031
0.014 Co: 0.12 Rem. 19 Embodiment 1.00 0.200 0.100 0.012 0.067 Zn:
0.13 Rem. 20 Comparison 0.92 0.051 0.0021 0.013 0.032 -- Rem.
embodiment
[0037] The finished softening-resistant copper alloy products in
Embodiments 21-40 of the present invention were obtained by
preparing materials according to the components and their mass
percentages of the softening-resistant copper alloy in Embodiments
1-20 in Table 1, then smelting, casting into an ingot, processing
and molding, heating to 450.degree. C. to 520.degree. C. at an
average heating rate of 1.degree. C./min to 30.degree. C./min and
holding this temperature for 2 h to 4 h (Embodiments 21-40 where
the finished products were obtained, corresponding to the
components and their mass percentages of the softening-resistant
copper alloy in Embodiments 1-20, respectively).
[0038] The microstructures of the finished softening-resistant
copper alloy products in Embodiments 21-40 were analyzed. The
results of analysis are shown in Table 2.
[0039] In the softening-resistant copper alloys in Embodiments
21-40 of the present invention, microscopic intermediate phases and
elementary substances with different properties are formed by
various added alloy elements and a particular aging process, and
the microscopic phases are dispersedly distributed in the copper
matrix, so that various performances of the copper alloys are
effectively improved. The related phases and their contents in the
softening-resistant copper alloys in Embodiments 21-40 of the
present invention are shown in Table 2.
TABLE-US-00002 TABLE 2 Intermediate phases and their contents in
the softening-resistant copper alloys in Embodiments 21-40 of the
present invention Embodiment Cr Cr.sub.3Si Cu.sub.5Zr Second phase
(wt %) (wt %) (wt %) Embodiment 21 0.0525 0.0975 0.0495 Embodiment
22 0.1045 0.0975 0.072 Embodiment 23 0.0435 0.1755 0.8505
Embodiment 24 0.119 0.143 0.1215 Embodiment 25 0.154 0.169 0.1305
Embodiment 26 0.224 0.169 0.207 Embodiment 27 0.2375 0.2275 0.216
Embodiment 28 0.251 0.247 0.2655 Embodiment 29 0.1525 0.4225 0.27
Embodiment 30 0.337 0.299 0.324 Embodiment 31 0.486 0.182 0.3555
Embodiment 32 0.3115 0.4355 0.3825 Embodiment 33 0.0312 0.624
0.4095 Embodiment 34 0.469 0.403 0.5175 Embodiment 35 0.609 0.273
0.5715 Embodiment 36 0.7855 0.1235 0.6705 Embodiment 37 0.7195
0.2015 0.6615 Embodiment 38 0.5155 0.5135 0.792 Embodiment 39 0.419
0.533 0.7965 Embodiment 40 0.4365 0.6305 0.873 Comparison 0.92 --
0.2295 embodiment
[0040] The materials were prepared according to the components and
their mass percentages of the softening-resistant copper alloy in
Embodiments 1-20 in Table 1, and then treated under the following
conditions: the casting temperature for the alloying treatment and
the covered refining was 1150.degree. C. to 1350.degree. C., the
temperature for hot extrusion was 850.degree. C. to 950.degree. C.,
the temperature for solid solution treatment was 850.degree. C. to
1000.degree. C., the cooling medium was water, the cooling rate was
10.degree. C./min to 150.degree. C./s, the machining rate of cold
drawing was 20% to 60%, the temperature for aging heat treatment
was 420.degree. C. to 520.degree. C., and the temperature holding
time was 2 h to 4 h. Finally, the finished softening-resistant
copper alloy bar products in 18 in Embodiments 41-60, corresponding
to the components and their mass percentages of the
softening-resistant copper alloy in Embodiments 1-20, were obtained
by finishing.
[0041] The tensile strength, hardness, electrical conductivity and
softening temperature of the softening-resistant copper alloy bars
in Embodiments 41-60 of the present invention were tested by
methods specified by the related national and industrial standards.
The test results are shown in Table 3.The room-temperature tensile
tests were carried out by an electronic universal mechanical
property testing machine according to GB/T228.1-2010 Metal Material
Tensile Test Section 1: Test at Room Temperature. The samples were
circular cross-section proportional samples having a proportional
coefficient of 5.65.The electrical conductivity tests were carried
out according to GB/T228.1-2010 Test Methods for Electrical
Performance of Electric Wires and Cables Section 2: Metal Material
Resistivity Test. As the test instrument, a ZFD microcomputer
bridge DC resistance tester was used, and the samples were 1000 mm
in length. The electrical conductivity was represented by % IACS.
The hardness tests were carried out by a hardometer according to
GB/T 230.1-2009 Metal Material: Rockwell Hardness Test.
TABLE-US-00003 TABLE 3 Test results of performances of the
softening-resistant copper alloy bars in Embodiments 41-60 of the
present invention Performance Tensile Electrical strength Hardness
conductivity Embodiment (MPa) (HR) (% IACS) Embodiment 41 472 75
90.1 Embodiment 42 491 77 88.6 Embodiment 43 482 75 91.1 Embodiment
44 487 78 86 Embodiment 45 496 78 85.7 Embodiment 46 499 80 86
Embodiment 47 489 81 84.2 Embodiment 48 492 80 85.1 Embodiment 49
498 82 83.8 Embodiment 50 506 81 84.1 Embodiment 51 517 84 81.2
Embodiment 52 528 86 79.1 Embodiment 53 509 82 76.4 Embodiment 54
558 87 75.2 Embodiment 55 537 85 76.3 Embodiment 56 568 85 77.7
Embodiment 57 566 87 77.5 Embodiment 58 571 86 76.8 Embodiment 59
573 86 75.7 Embodiment 60 578 88 75.2 Comparison 495 85 83.1
embodiment
[0042] In the present invention, the tensile strength is higher
than or equal to 470 MPa, the Rockwell hardness is above 75, and
the electrical conductivity is above 75% IACS.
[0043] Embodiments 61-80 The components and their mass percentages
of the softening-resistant copper alloys in Embodiments 61-80 are
the same as those in Embodiments 41-60. That is, the materials were
prepared according to the components and their mass percentages of
the softening-resistant copper alloy in Embodiments 1-20 in Table
1, and then treated under the following conditions: the casting
temperature for the alloying treatment and the covered refining was
1150.degree. C. to 1350.degree. C., the temperature for hot
extrusion was 850.degree. C. to 950.degree. C., the temperature for
solid solution treatment was 850.degree. C. to 1000.degree. C., the
cooling medium was water, the cooling rate was 10.degree. C./min to
150.degree. C./s, the machining rate of cold drawing was 20% to
60%, the temperature for aging heat treatment was 420.degree. C. to
520.degree. C., and the temperature holding time was 2 h to 4 h.
Finally, the finished softening-resistant copper alloy bar products
in .PHI.8 were obtained by finishing.
[0044] The softening temperature tests were carried out by methods
specified by HB5420-89 Copper and Copper Alloys for Resistance
Welding Electrodes and Auxiliary Devices. The test temperature was
580.degree. C. The test results are shown in Table 4.
TABLE-US-00004 TABLE 4 Test results of the softening temperature of
the softening-resistant copper alloy bars in Embodiments 61-80 of
the present invention Original 580.degree. C. hardness Hardness
after Softening Embodiment (HRB) softening (HRB) rate (%)
Embodiment 61 75 70 6.67 Embodiment 62 77 71 7.79 Embodiment 63 75
69 8 Embodiment 64 78 73 6.41 Embodiment 65 78 72 7.69 Embodiment
66 80 75 6.25 Embodiment 67 81 77 4.94 Embodiment 68 80 76 5
Embodiment 69 82 76 7.32 Embodiment 70 81 75 7.41 Embodiment 71 84
79 5.95 Embodiment 72 86 80 6.98 Embodiment 73 82 78 4.88
Embodiment 74 87 81.5 6.32 Embodiment 75 85 80 5.88 Embodiment 76
85 81 4.71 Embodiment 77 87 81 6.90 Embodiment 78 86 80 6.98
Embodiment 79 86 81 5.81 Embodiment 80 88 82 6.82 Comparison 85 69
18.8 embodiment
[0045] It can be deduced from the above embodiments that, in
accordance with the standard test methods, the hardness loss of the
copper alloy of the present invention at 580.degree. C. is below
8%, while the hardness loss of the conventional copper chromium
zirconium alloy in the comparison embodiment is greater than 18%.
It is indicated that the high-temperature softening resistance of
the copper alloy of the present invention is greatly improved.
Application Embodiment
[0046] The softening-resistant copper alloy bars in anyone of
Embodiments 41-60 are machined into appliances for welding.
[0047] The softening-resistant copper alloy bars in anyone of
Embodiments 41-60 are machined into contact lines for electrified
railways.
[0048] In conclusion, the softening-resistant copper alloy of the
present invention has high strength, good electrical performance
and excellent high-temperature softening resistance, and is
particularly applied in industrial fields such as welding
appliances and contact lines for electrified railways.
* * * * *