BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to lead-free, free-cutting copper alloys.
2. Prior Art
[0002] Among the copper alloys with a good machinability are bronze alloys such as the one
under JIS designation H5111 BC6 and brass alloys such as the ones under JIS designations
H3250-C3604 and C3771. Those alloys are enhanced in machinability by the addition
of 1.0 to 6.0 percent, by weight, of lead and provide an industrially satisfactory
machinability. Because of their excellent machinability, those lead-contained copper
alloys have been an important basic material for a variety of articles such as city
water faucets, water supply/drainage metal fittings and valves.
[0003] However, the application of those lead-mixed alloys has been greatly limited in recent
years, because lead contained therein is an environment pollutant harmful to humans.
That is, the lead-containing alloys pose a threat to human health and environmental
hygiene because lead is contained in metallic vapour that is generated in the steps
of processing those alloys at high temperatures such as melting and casting and there
is also concern that lead contained in the water system metal fittings, valves and
others are made of those alloys will dissolve out into drinking water.
[0004] On that ground, the United States and other advanced countries have been moving to
tighten the standards for lead-contained copper alloys to drastically limit the permissible
level of lead in copper alloys in recent years. Japan, too, the use of lead-contained
alloys has been increasingly restricted, and there has been a growing call for development
of free-cutting copper alloys with a low lead content.
[0005] The document
GB-A-359 570 discloses a copper-silicon-zinc alloy with a content of 65 to 80 % of copper and
2 to 6 % of silicon.
[0006] The document
US-A-1 954 003 discloses an alloy consisting of from 65 % and up to 94 % copper, from 2 % to 6 %
silicon, from 3 % to 28 % zinc, and not more than 2 % aluminum.
[0007] The document
GB-A-354 966 discloses copper-silicon-zinc alloys with up to 6 % silicon and up to 20 % zinc.
[0008] The document
US-A-3 900 349 discloses a silicon brass alloy consisting of 3-21 weight % zinc, 2.5 to 7 weight
% silicon, said amounts of zinc and silicon being sufficient to produce a structure
consisting of alpha plus zeta phases in the brass, from 0.030 weight % up to the percentage
by weight of solid solubility of one or more elements of the group consisting of arsenic,
antimony and phosphorus, remainder being copper.
[0009] The document
GB-A-1 443 090 discloses a silicon brass alloy consisting of 3-21 weight % zinc, 2.5 to 6 weight
% silicon, said amounts of zinc and silicon being sufficient to produce a structure
consisting of alpha plus zeta phases in the brass, from 0.030 weight % up to the percentage
by weight of solid solubility of one or more elements of the group consisting of arsenic,
antimony and phosphorus, remainder being copper.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to provide a lead-free copper alloy which
does not contain the machinability-improving element lead yet is quite excellent in
machinability and can be used as safe substitute for the conventional free cutting
copper alloy with a large content of lead presenting environmental hygienic problems
which permits recycling of chips without problems, thus a timely answer to the mounting
call for restriction of lead-contained products.
[0011] It is an another object of the present invention to provide a lead-free copper alloy
which has a high corrosion resistance as well as an excellent machinability and is
suitable as basic material for cutting works, forgings, castings and others, thus
having a very high practical value. The cutting works, forgings, castings and others
include city water faucets, water supply/drainage metal fittings, valves, stems, hot
water supply pipe fittings, shaft and heat exchanger parts.
[0012] It is yet another object of the present invention to provide a lead-free copper alloy
with a high strength and wear resistance as well as machinability which is suitable
as basic material for the manufacture of cutting works, forgings, castings and other
uses requiring a high strength and wear resistance such as, for example, bearings,
bolts, nuts, bushes, gears, sewing machine parts and hydraulic system parts, hence
has a very high practical value.
[0013] It is a further object of the present invention to provide a lead-free copper alloy
with an excellent high-temperature oxidation resistance as well as machinability which
is suitable as basic material for the manufacture of cutting works, forgings, castings
and other uses where a high thermal oxidation resistance is essential, e.g. nozzles
for kerosene oil and gas heaters, burner heads and gas nozzles for hot-water dispensers,
hence has a very high practical value.
[0014] The objects of the present inventions are achieved by the present invention, thus:
[0015] In a first aspect, the present invention provides a lead-free, free-cutting copper
alloy which comprises 70 to 80 percent, by weight, of copper; 1.8 to 3.5 percent,
by weight, of silicon; 0.02 to 0.25 percent, by weight, of phosphorous and the remaining
percent, by weight, of zinc and wherein the metal structure of the free cutting copper
alloy has at least one phase selected from the γ (gamma) phase and the κ (kappa) phase.
[0016] Tin works the same way as silicon. That is, if tin is added to a Cu-Zn alloy, a gamma
phase will be formed and the machinability of the Cu-Zn alloy will be improved. For
example, the addition of tin in as amount of 1.8 to 4.0 percent by weight would bring
about a high machinability in the Cu-Zn alloy containing 58 to 70 percent, by weight,
of copper, even if silicon is not added. Therefore, the addition of tin to the Cu-Si-Zn
alloy could facilitate the formation of a gamma phase and further improve the machinability
of the Cu-Si-Zn alloy. The gamma phase is formed with the addition of tin in an amount
of 1.0 or more percent by weight and the formation reaches the saturation point at
3.5 percent, by weight, of tin. If tin exceeds 3.5 percent by weight, the ductility
will drop instead. With the addition of tin in less than 1.0 percent by weight, on
the other hand, no gamma phase will be formed. If the addition is 0.3 percent or more
by weight, then tin will be effective in uniformly dispersing the gamma phase formed
by silicon. Through that effect of dispersing the gamma phase, too, the machinability
is improved. In other words, the addition of tin in not smaller than 0.3 percent by
weight improves the machinability.
[0017] Aluminum is, too, effective in promoting the formation of the gamma phase. The addition
of aluminum together with tin or in place of tin could further improve the machinability
of the Cu-Si-Zn. Aluminum is also effective in improving the strength, wear resistance
and high temperature oxidation resistance as well as the machinability and also in
keeping down the specific gravity. If the machinability is to be improved at all,
aluminum will have to be added in at least 1.0 percent by weight But the addition
of more than 3.5 percent by weight could not produce the proportional results. Instead,
that could affect the ductility as is the case with aluminum.
[0018] As to phosphorus, it has no property of forming the gamma phase as tin and aluminum.
But phosphorus works to uniformly disperse and distribute the gamma phase formed as
a result of the addition of silicon alone or with tin or aluminum or both of them.
That way, the machinability improvement through the formation of gamma phase is further
enhanced. In addition to dispersing the gamma phase, phosphorus helps refine the crystal
grains in the alpha phase in the matrix, improving hot workability and also strength
and resistance to stress corrosion cracking. Furthermore, phosphorous substantially
increases the flow of molten metal in casting. To produce such results, phosphorus
will have to be added in an amount not smaller than 0.02 percent by weight. But if
the addition exceeds 0.25 percent by weight, no proportional effect can be obtained.
Instead, there would be a fall in hot forging property and extrudability.
[0019] In consideration of those observations, the alloy of the present invention has improved
machinability by adding to the Cu-Si-Zn-P alloy at least one element selected from
0.3 to 3.5 percent, by weight, of tin and from 1.0 to 3.5 percent, by weight, of aluminum.
[0020] Meanwhile, tin, aluminum and phosphorus are to improve the machinability by forming
a gamma phase or dispersing that phase, and work closely with silicon in promoting
the improvement in machinability through the gamma phase. In the alloy of the present
invention mixed with silicon along with tin or aluminum therefore, machinability is
improved by not only silicon, but by tin or aluminum. Even if the addition of silicon
is less than 2.0 percent by weight, silicon along with tin or aluminum will be able
to enhance the machinability to an industrially satisfactory level as long as the
percentage of silicon is 1.8 or more percent by weight. But even if the addition of
silicon is not larger than 4.0 percent by weight, the addition of tin or aluminum
will saturate the effect of silicon in improving the machinability, when the silicon
content exceeds 3.5 percent by weight. On this ground, the addition of silicon is
set at 1.8 to 3;.5 percent by weight in the alloy of the present invention.
[0021] The alloy of the present invention may additionally comprise at least one element
selected from among 0.02 to 0.4 percent, by weight, of bismuth, 0.02 to 0.4 percent,
by weight, of tellurium, and 0.02 to 0.4 percent, by weight, of selenium.
[0022] Bismuth, tellurium and selenium as well as lead do not form a solid solution in the
matrix but disperse in granular form to enhance the machinability and that through
a mechanism different from that of the silicon. Hence, the addition of those elements
along with silicon could further improve the machinability beyond the level obtained
by the addition of silicon alone. From this finding, the alloy of the present invention
may further comprise at least one element selected from bismuth, tellurium and selenium
mixed to improve further the machinability obtained by the first invention alloy.
The addition of bismuth, tellurium or selenium in addition to silicon produces a high
machinability such that complicated forms could be freely cut at a high speed. But
no improvement in machinability can be realised from the addition of bismuth, tellurium
or selenium in an amount less than 0.02 percent, by weight. Meanwhile, those elements
are expensive as compared with copper. Even if the addition exceeds 0.4 percent by
weight, the proportional improvement in machinability is so small that the addition
beyond that does not pay economically. What is more, if the addition is more than
0.4 percent by weight, the alloy will deteriorate in hot workability such as forgeability
and cold workability such as ductility. While it might be feared that heavy metals
like bismuth would cause problems similar to those of lead, an addition in a very
small amount of less than 0.4 percent by weight is negligible and would present no
particular problems. The addition of those elements, which work on the machinability
of the copper alloy through a mechanism different from that of silicon as mentioned
above, would not affect the proper contents of copper and silicon.
[0023] The present invention also provides a method of forming a lead-free, free cutting
alloy having a metal structure which has at least one phase selected from the γ (gamma)
phase and the κ (kappa) phase which comprises alloying copper, silicon, phosphorous
and zinc in an amount of 70 to 80 percent, by weight, of copper, 1.8 to 3.5 percent,
by weight, of silicon; 0.02 to 0.25 percent, by weight, of phosphorus and the remaining
percent by weight of zinc.
[0024] The method of the present invention may also further comprise subjecting said lead
free, free cutting alloy to a heat treatment for 30 minutes to 5 hours at 400°C to
600°C.
[0025] The alloys of the present invention contain machinability improving elements such
as silicon and have an excellent machinability because of the addition of such elements.
Of those invention alloys, the alloys with a high copper content which have great
amounts of other phases, mainly kappa phase, than alpha, beta, gamma and delta phases
can further improve in machinability in a heat treatment. In the heat treatment, the
kappa phase turns to a gamma phase. The gamma phase finely disperses and precipitates
to further enhance the machinability. The alloys with a high content of copper are
high in ductility of the matrix and low in absolute quantity of gamma phase, and therefore
are excellent in cold workability. But in case cold working such as caulking and cutting
are required, the aforesaid heat treatment is very useful. In other words those alloys
of the present invention which are high in copper content with gamma phase in small
quantities and kappa phase in large quantities (hereinafter referred to as the "high
copper content alloy") undergo a change in phase from the kappa phase to the gamma
phase in a heat treatment. As a result, the gamma phase is finely dispersed and precipitated,
and the machinability is improved. In the manufacturing process of castings, expanded
metals and hot forgings in practice, the materials are often force-air-cooled or water
cooled depending on the forging conditions, productivity after hot working (hot extrusion,
hot forging etc.), working environment and other factors. In such cases, among the
alloys of the present invention those with a low content of copper (hereinafter called
the "low copper content alloy") are rather low in the content of the gamma phase and
contain beta phase. In a heat treatment, the beta phase changes into gamma phase,
and the gamma phase is finely dispersed and precipitated, whereby the machinability
is improved. Experiments showed that heat treatment is especially effective with high
copper content alloys where mixing ration of copper and silicon to other added elements
(except for zinc) A is given as 67 ≤ Cu - 3Si + aA or low copper content alloys with
such a composition with 64 ≥ Cu - 3Si + aA
. It is noted that a is a coefficient. The coefficient is different depending on the
added element A. For example, with tin a is - 0.5; aluminum, -2; phosphorus, -3; antimony,
0; arsenic, 0; manganese, +2.5; and nickel, +2.5.
[0026] But a heat treatment temperature at less than 400°C is not economical and practical,
because the aforesaid phase change will proceed slowly and much time will be needed.
At temperatures over 600 C, on the other hand, the kappa phase will grow or the beta
phase will appear, bringing about no improvement in machinability. From the practical
viewpoint, therefore, it is desired to perform the heat treatment for 30 minutes to
5 hours at 400 to 600°C.
BRIEF DESCRIPTION OF THE DRAWING
[0027] Fig. 1 shows perspective views of cuttings formed in cutting a round bar of copper
alloy by lathe.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Example 1
[0028] As the first series of examples of the present invention, cylindrical ingots with
compositions given in Tables 1 to 4, each 100 mm in outside diameter and 150 mm in
length, were hot extruded into a round bar 15 mm in outside diameter at 750°C to produce
the following test pieces: invention alloys Nos 3004 to 3007 and 3010 to 3012, and
4022 to 4049.
[0029] As comparative examples, cylindrical ingots with the compositions as shown in Table
5, each 100 mm in outside diameter and 150 mm in length, were hot extruded into a
round bar 15 mm in outside diameter at 750°C to obtain the following round extruded
test pieces: Nos. 14001 to 14006 (hereinafter referred to as the "conventional alloys").
No. 14001 corresponds to the alloys "JIS C 3604," No. 14002 to the alloy "CDA C 36000,"
No. 14003 to the alloy "JIS C 3771" and No. 14004 to the alloy "CDA C 69800." No.
14005 corresponds to the alloy "JIS C 6191". This aluminum bronze is the most excellent
of the expanded copper alloys under the JIS designations with regard to strength and
wear resistance. No. 14006 corresponds to the naval brass alloy "JIS C 4622" and is
the most excellent of the expanded copper alloys under the JIS designations with regard
to corrosion resistance.
[0030] To study the machinability of the alloys of the invention in comparison with the
conventional alloys, cutting tests were carried out. In the tests, evaluations were
made on the basis of cutting force, condition of chips cut surface condition.
[0031] The tests were conducted this way: The extruded test pieces obtained, as mentioned
above, were cut on the circumferential surface by a lathe mounted with a point nose
straight tool at a rake angle of - 8 degrees and at a cutting rate of 50 meters/minute,
a cutting depth of 1.5 mm, a feed of 0.11 mm/rev. Signals from a three-component dynamometer
mounted on the tool were converted into electric voltage signals and recorded on a
recorder. From the signals were then calculated the cutting resistance. It is noted
that while, to be perfectly exact, an amount of the cutting resistance should be judged
by three component forces - cutting force, feed force and thrust force, the judgement
was made on the basis of the cutting force (N) of the three component forces in the
present example. The results are shown in Table 6 to Table 10.
[0032] Furthermore, the chips from the cutting work were examined and classified into four
forms (A) to (D) as shown in Fig. 1. The results are enumerated in Table 6 to Table
10. In this regard, the chips in the form of a spiral with three or more windings
as (D) in Fig. 1 are difficult to process, that is, recover or recycle, and could
cause trouble in cutting work as, for example, getting tangled with the tool and damaging
the cut metal surface. Chips in the form of an arc with a half winding to a spiral
with two about windings as shown in (C), Fig. 1 do not cause such serious trouble
as the chips in the form of a spiral with three or more windings yet are not easy
to remove and could get tangled with the tool or damage the cut metal surface. In
contrast, chips in the form of a fine needle as (A) in Fig. 1 or in the form of an
arc as (B) will not present such problems as mentioned above and are not bulky as
the chips in (C) and (D) and easy to process. But fine chips (A) still could creep
into the sliding surfaces of a machine tool such as a lathe and cause mechanical trouble,
or could be dangerous because they could stick into the worker's finger, eye or other
body parts. Those taken into account, it is appropriate to consider the chips in (B)
are the best, and the second best are the chips in (A). Those in (C) and (D) are not
good. In Table 6 to Table 10, the chips judged to be shown in (B), (A), (C) and (D)
are indicated by the symbols "⊚", "o", "Δ" and "x" respectively.
[0033] In addition, the surface condition of the cut metal surface was checked after cutting
work. The results are shown in Table 6 to Table 10. In this regard, the commonly used
basis for indication of the surface roughness is the maximum roughness (Rmax). While
requirements are different depending on the application field of the brass articles,
the alloys with Rmax < 10 microns are generally considered excellent in machinability.
The alloys with 10 microns ≤ Rmax < 15 microns are judged as industrially acceptable,
while those with Rmax ≥ 15 microns are taken as poor in machinability. In Table 6
to Table 9, the alloys with Rmax < 10 microns are marked "o", those with 10 microns
≤ Rmax < 15 microns are indicated as "Δ" and those with Rmax ≥15 microns are represented
by a symbol "x".
[0034] As is evident from me results of the cutting tests shown in Table 6 to Table 10,
the invention alloys 3004 to 3007 and 3010 to 3012 are all equal to the conventional
lead- contained alloys Nos. 14001 to 14003 in machinability. Especially with regard
to formation of the chips, those invention alloys are favourably compared not only
with the conventional alloys Nos. 14004 to 14006 with a lead content of not higher
than 0.1 percent by weight but also Nos. 14001 to 14003 which contain large quantities
of lead.
[0035] In another series of tests, the alloys of the present invention were examined in
comparison with the conventional alloys in hot workability and mechanical properties.
For the purpose, hot compression and tensile tests were conducted the following way.
[0036] First, two test pieces, first and second test pieces, in the same shape 15 mm in
outside diameter and 25 mm in length were cut out of each extruded test piece obtained
as described above. In the hot compression tests, the first test piece was held for
30 minutes at 700°C, and then compressed 70 percent in the direction of axis to reduce
the length from 25 mm to 7.5 mm. The surface condition after the compression (700°C
deformability) was visually evaluated. The results are given in Table 6 to Table 10.
The evaluation of deformability was made by visually checking for cracks on the side
of the test piece. In Table 6 to Table 10, the test pieces with not cracks found are
marked "o", those with small cracks are indicated in "Δ" and those with large cracks
are represented by symbol "x".
[0037] The second test pieces were put to a tensile test by the commonly practiced test
method to determine the tensile strength, N/mm
2 and elongation, %.
[0038] As the test results of the hot compression and tensile tests in Table 6 to Table
10 indicate, it was confirmed that the alloys of the present invention are equal to
or superior to the conventional alloys Nos. 14001 to 14004 and No. 14006 in hot workability
and mechanical properties and are suitable for industrial use.
[0039] Furthermore, the alloys of the present invention were put to dezincification and
stress corrosion cracking tests in accordance with the test methods specified under
"ISO 6509" and "JIS H 3250" respectively to examine the corrosion resistance and resistance
to stress corrosion cracking in comparison with the conventional alloys.
[0040] In the dezincification test by the "ISO 6509" method, a sample taken from each extruded
test piece was imbedded in a phenolic resin material in such a way that part of the
side surface of the sample is exposed, the exposed surface perpendicular to the extrusion
direction of the extruded test piece. The surface of the example was polished with
emery paper No. 1200, and then ultrasonic-washed in pure water and dried. The sample
thus prepared was dipped in a 12.7 g/l aqueous solution of cupric chloride dihydrate
(CUCl
2.2H
2O) 1.0% and left standing for 24 hours at 75°C. The sample was taken out of the aqueous
solution and the maximum depth of dezincification was determined. The measurements
of the maximum dezincification depth are given in Table 6 to Table 10.
[0041] As is clear from the results of dezincification tests shown in Table 6 to table 10,
the alloys of the present invention are excellent in corrosion resistance and favourable
comparable with the conventional alloys Nos. 14001 to 14003 containing great amounts
of lead.
[0042] In the stress corrosion cracking tests in accordance with the test method described
in "JIS H 3250," a 150-mm long sample was cut out from each extruded test piece. The
sample was bent with its centre placed on an arc shaped tester with a radius of 40
mm in such a way that one end and the other end subtend an angle of 45 degrees. The
test sample thus subjected to a tensile residual stress was degreased and dried, and
then placed in an ammonia environment in the desiccator with a 12.5% aqueous ammonia
(ammonia diluted in the equivalent of pure water). To be exact, the test sample was
held some 80 mm above the surface of aqueous ammonia in the desiccator. After the
test sample was left standing in the ammonia environment for two hours, 8 hours and
24 hours, the test sample was taken out from the desiccator, washed in sulphuric acid
solution 10% and examined for cracks under a magnifier of 10 magnifications. The results
are given in Table 6 to Table 10. In those tables, the alloys which have developed
clear cracks when held in the ammonia environment for two hours are marked "xx." The
test samples which had no cracks at passage of two hours but were found to have clear
cracks at 8 hours are indicated by "x." The test samples which had no cracks at 8
hours, but were found to have clear cracks at 24 hours were indicated by "Δ". The
test samples which were found to have no cracks at all at least 24 hours are given
a symbol "o."
[0043] As is indicated by the results of the stress corrosion cracking test given in Table
6 to Table 10, it was confirmed that the alloys of the present invention, in which
nothing particular was done to improve corrosion resistance, were both equal to the
conventional alloy No. 14005, an aluminum bronze containing no zinc, in stress corrosion
cracking resistance and were superior in stress corrosion cracking resistance to the
conventional naval brass alloy No. 14006, the one which has a highest corrosion resistance
of all the expanded copper alloys under the JIS designations.
[Table 1]
No. |
alloy composition (wt%) |
Cu |
Si |
Sn |
Al |
P |
Zn |
3001* |
71.8 |
2.4 |
3.1 |
|
|
remainder |
3002* |
78.2 |
2.3 |
|
3.3 |
|
remainder |
3003* |
75.0 |
1.9 |
1.5 |
1.4 |
|
remainder |
3004 |
74.9 |
3.2 |
|
|
0.09 |
remainder |
3005 |
71.6 |
2.4 |
2.3 |
|
0.03 |
remainder |
3006 |
76.5 |
2.7 |
|
2.4 |
0.21 |
remainder |
3007 |
76.5 |
3.1 |
0.6 |
1.1 |
0.04 |
remainder |
3008* |
77.5 |
3.5 |
0.4 |
|
|
remainder |
3009* |
75.4 |
3.0 |
1.7 |
|
|
remainder |
3010 |
76.5 |
3.3 |
|
|
0.21 |
remainder |
3011 |
73.8 |
2.7 |
|
|
0.04 |
remainder |
3012 |
75.0 |
2.9 |
1.6 |
|
0.10 |
remainder |
* out of the scope of the invention |
[Table 2]*
No. |
alloy composition (wt%) |
Cu |
Si |
Sn |
Al |
Bi |
Te |
Se |
Zn |
4001 |
70.8 |
1.9 |
3.4 |
|
0.36 |
|
|
remainder |
4002 |
76.3 |
3.4 |
1.3 |
|
|
0.03 |
|
remainder |
4003 |
73.2 |
2.5 |
1.9 |
|
|
|
0.15 |
remainder |
4004 |
72.3 |
2.4 |
0.6 |
|
0.29 |
0.23 |
|
remainder |
4005 |
74.2 |
2.7 |
2.0 |
|
0.03 |
|
0.26 |
remainder |
4006 |
75.4 |
2.9 |
0.4 |
|
|
0.31 |
0.03 |
remainder |
4007 |
71.5 |
2.1 |
2.6 |
|
0.11 |
0.05 |
0.23 |
remainder |
4008 |
79.1 |
1.9 |
|
3.3 |
0.28 |
|
|
remainder |
4009 |
76.3 |
2.7 |
|
1.2 |
|
0.13 |
|
remainder |
4010 |
77.2 |
2.5 |
|
2.0 |
|
|
0.07 |
remainder |
4011 |
79.2 |
3.1 |
|
1.1 |
0.04 |
0.06 |
|
remainder |
4012 |
76.3 |
2.3 |
|
1.3 |
0.13 |
|
0.04 |
remainder |
4013 |
77.4 |
2.6 |
|
2.6 |
|
0.22 |
0.03 |
remainder |
4014 |
77.9 |
2.2 |
|
2.3 |
0.09 |
0.05 |
0.11 |
remainder |
4015 |
73.5 |
2.0 |
2.9 |
1.2 |
0.23 |
|
|
remainder |
4016 |
76.3 |
2.5 |
0.7 |
3.2 |
|
0.04 |
|
remainder |
4017 |
75.5 |
2.3 |
1.2 |
2.0 |
|
|
0.12 |
remainder |
4018 |
77.1 |
2.1 |
0.9 |
3.4 |
0.03 |
0.03 |
|
remainder |
4019 |
72.9 |
3.2 |
3.3 |
1.7 |
0.11 |
|
0.04 |
remainder |
4020 |
74.2 |
2.8 |
2.7 |
1.1 |
|
0.33 |
0.03 |
remainder |
* alloys of table 2 out of the scope of the invention |
[Table 3]
No. |
alloy composition (wt%) |
Cu |
Si |
Sn |
Al |
Bi |
Te |
Se |
P |
Zn |
4021* |
74.2 |
2.3 |
1.5 |
2.3 |
0.07 |
0.05 |
0.09 |
|
remainder |
4022 |
70.9 |
2.1 |
|
|
0.11 |
|
|
0.11 |
remainder |
4023 |
74.8 |
3.1 |
|
|
|
0.07 |
|
0.06 |
remainder |
4024 |
76.3 |
3.2 |
|
|
|
|
0.05 |
0.02 |
remainder |
4025 |
78.1 |
3.1 |
|
|
0.26 |
0.02 |
|
0.15 |
remainder |
4026 |
71.1 |
2.2 |
|
|
0.13 |
|
0.02 |
0.05 |
remainder |
4027 |
74.1 |
2.7 |
|
|
0.03 |
0.06 |
0.03 |
0.03 |
remainder |
4028 |
70.6 |
1.9 |
3.2 |
|
0.31 |
|
|
0.04 |
remainder |
4029 |
73.6 |
2.4 |
2.3 |
|
|
0.03 |
|
0.04 |
remainder |
4030 |
73.4 |
2.6 |
1.7 |
|
|
|
0.31 |
0.22 |
remainder |
4031 |
74.8 |
2.9 |
0.5 |
|
0.03 |
0.02 |
|
0.05 |
remainder |
4032 |
73.0 |
2.6 |
0.7 |
|
0.09 |
|
0.02 |
0.08 |
remainder |
4033 |
74.5 |
2.8 |
|
|
|
0.03 |
0.12 |
0.05 |
remainder |
4034 |
77.2 |
3.3 |
1.3 |
|
|
0.03 |
0.12 |
0.04 |
remainder |
4035 |
74.9 |
3-1 |
0.4 |
|
0.02 |
0.05 |
0.05 |
0.08 |
remainder |
4036 |
79.2 |
3.3 |
|
2.5 |
0.05 |
|
|
0.12 |
remainder |
4037 |
74.2 |
2.6 |
|
1.2 |
|
0.12 |
|
0.05 |
remainder |
4038 |
77.0 |
2.8 |
|
1.3 |
|
|
0.05 |
0.20 |
remainder |
4039 |
76.0 |
2.4 |
|
3.2 |
0.10 |
0.04 |
|
0.05 |
remainder |
4040 |
74.8 |
2.4 |
|
1.1 |
0.07 |
|
0.04 |
0.03 |
remainder |
* out of the scope of the invention |
[Table 4]
No. |
alloy composition (wt%) |
Cu |
Si |
Sn |
Al |
Bi |
Te |
Se |
P |
Zn |
4041 |
77.2 |
2.7 |
|
2.1 |
|
0.33 |
0.05 |
0.05 |
remainder |
4042 |
78.0 |
2.6 |
|
2.5 |
0.03 |
0.02 |
0.10 |
0.14 |
remainder |
4043 |
72.5 |
2.4 |
1.9 |
1.1 |
0.12 |
|
|
0.03 |
remainder |
4044 |
76.0 |
2.6 |
0.5 |
2.0 |
|
0.20 |
|
0.07 |
remainder |
4045 |
77.5 |
2.6 |
0.7 |
3.1 |
|
|
0.21 |
0.12 |
remainder |
4046 |
75.0 |
2.6 |
0.8 |
2.2 |
0.04 |
0.05 |
|
0.06 |
Remainder |
4047 |
71.0 |
1.9 |
3.1 |
1.0 |
0.15 |
|
0.02 |
0.04 |
remainder |
4048 |
73.3 |
2.1 |
2.6 |
1.2 |
|
0.04 |
0.03 |
0.05 |
remainder |
4049 |
74.8 |
2.5 |
0.6 |
1.1 |
0.03 |
0.03 |
0.04 |
0.07 |
remainder |
[Table 5]
No. |
Alloy composition (wt%) |
Cu |
Si |
Sn |
Al |
Mn |
Pb |
Fe |
Ni |
Zn |
14001 |
58.8 |
|
0.2 |
|
|
3.1 |
0.2 |
|
remainder |
14001a |
14002 |
61.4 |
|
0.2 |
|
|
3.0 |
0.2 |
|
remainder |
14002a |
14003 |
59.1 |
|
0.2 |
|
|
2.0 |
0.2 |
|
remainder |
14003a |
14004 |
69.2 |
1.2 |
|
|
|
0.1 |
|
|
remainder |
14004a |
14005 |
remainder |
|
|
9.8 |
1.1 |
|
3.9 |
1.2 |
|
14005a |
14006 |
61.8 |
|
1.0 |
|
|
0.1 |
|
|
remainder |
14006a |
[Table 6]
No. |
machinability |
corrosion resistance |
hot workabitily |
mechanical properties |
stress resistance corrosion cracking resistance |
form of chippings |
condition of cut surface |
cutting force (N) |
maximum depth of corrosion (µm) |
700°C deformability |
tensile strength (N/mm2) |
elongation (%) |
3001 |
⊚ |
Δ |
128 |
40 |
○ |
553 |
26 |
○ |
3002 |
⊚ |
○ |
126 |
130 |
Δ |
538 |
32 |
○ |
3003 |
⊚ |
○ |
126 |
50 |
○ |
526 |
28 |
○ |
3004 |
⊚ |
○ |
119 |
<5 |
○ |
533 |
36 |
○ |
3005 |
⊚ |
○ |
125 |
50 |
○ |
525 |
28 |
○ |
3006 |
⊚ |
○ |
120 |
<5 |
○ |
546 |
38 |
○ |
3007 |
⊚ |
○ |
121 |
<5 |
○ |
552 |
34 |
○ |
3008 |
⊚ |
○ |
122 |
80 |
○ |
570 |
36 |
○ |
3009 |
⊚ |
○ |
123 |
50 |
○ |
541 |
29 |
○ |
3010 |
⊚ |
○ |
118 |
<5 |
○ |
560 |
35 |
○ |
3011 |
⊚ |
○ |
119 |
20 |
○ |
502 |
34 |
○ |
3012 |
⊚ |
○ |
120 |
<5 |
○ |
534 |
31 |
○ |
[Table 7]
No. |
machinability |
corrosion resistance |
hot workability |
mechanical properties |
stress resistance corrosion cracking resistance |
form of chippings |
condition of cut surface |
cutting force (N) |
maximum depth of corrosion (µm) |
700°C deformability |
tensile strength (N/mm2) |
elongation (%) |
4001 |
⊚ |
○ |
119 |
40 |
Δ |
512 |
24 |
○ |
4002 |
⊚ |
○ |
122 |
50 |
○ |
543 |
30 |
○ |
4003 |
⊚ |
○ |
123 |
50 |
○ |
533 |
30 |
○ |
4004 |
⊚ |
○ |
117 |
80 |
Δ |
520 |
31 |
○ |
4005 |
⊚ |
○ |
119 |
50 |
○ |
535 |
32 |
○ |
4006 |
⊚ |
○ |
116 |
60 |
○ |
532 |
31 |
○ |
4007 |
⊚ |
○ |
122 |
50 |
○ |
528 |
26 |
○ |
4008 |
⊚ |
○ |
124 |
100 |
Δ |
554 |
30 |
○ |
4009 |
⊚ |
○ |
119 |
130 |
○ |
542 |
34 |
○ |
4010 |
⊚ |
○ |
119 |
120 |
○ |
562 |
35 |
○ |
4011 |
⊚ |
○ |
122 |
100 |
Δ |
563 |
34 |
○ |
4012 |
⊚ |
○ |
119 |
130 |
○ |
524 |
40 |
○ |
4013 |
⊚ |
○ |
120 |
110 |
○ |
548 |
37 |
○ |
4014 |
⊚ |
○ |
120 |
120 |
Δ |
539 |
36 |
○ |
4015 |
⊚ |
○ |
121 |
40 |
○ |
528 |
28 |
○ |
4016 |
⊚ |
○ |
122 |
60 |
○ |
597 |
32 |
○ |
4017 |
⊚ |
○ |
120 |
50 |
○ |
520 |
33 |
○ |
4018 |
⊚ |
○ |
123 |
60 |
○ |
553 |
31 |
○ |
4019 |
⊚ |
○ |
118 |
40 |
○ |
606 |
24 |
○ |
4020 |
⊚ |
○ |
120 |
40 |
○ |
561 |
26 |
○ |
[Table 8]
No. |
machinability |
corrosion resistance |
hot work ability |
mechanical properties |
stress resistance corrosion cracking resistance |
form of chip pings |
condition of cut surface |
cutting force (N) |
maximum depth of corrosion (µm) |
700°C deformability |
tensile strength (N/mm2) |
elongation (%) |
4021 |
⊚ |
○ |
120 |
50 |
○ |
540 |
29 |
○ |
4022 |
⊚ |
○ |
123 |
<5 |
○ |
487 |
32 |
Δ |
4023 |
⊚ |
○ |
117 |
<5 |
○ |
524 |
34 |
○ |
4024 |
⊚ |
○ |
117 |
40 |
○ |
541 |
37 |
○ |
4025 |
⊚ |
○ |
115 |
<5 |
Δ |
526 |
43 |
○ |
4026 |
⊚ |
○ |
122 |
30 |
○ |
498 |
30 |
Δ |
4027 |
⊚ |
○ |
118 |
30 |
○ |
516 |
35 |
○ |
4028 |
⊚ |
○ |
120 |
<5 |
○ |
529 |
27 |
○ |
4029 |
⊚ |
○ |
121 |
<5 |
○ |
544 |
28 |
○ |
4030 |
⊚ |
○ |
118 |
<5 |
○ |
536 |
30 |
○ |
4031 |
⊚ |
○ |
116 |
<5. |
○ |
524 |
31 |
○ |
4032 |
⊚ |
○ |
114 |
<5 |
○ |
515 |
32 |
○ |
4033 |
⊚ |
○ |
118 |
<5 |
○ |
519 |
37 |
○ |
4034 |
⊚ |
○ |
118 |
<5 |
○ |
582 |
31 |
○ |
4035 |
⊚ |
○ |
117 |
<5 |
○ |
538 |
32 |
○ |
4036 |
⊚ |
○ |
118 |
<5 |
Δ |
600 |
34 |
○ |
4037 |
⊚ |
○ |
117 |
20 |
○ |
523 |
34 |
○ |
4038 |
⊚ |
○ |
116 |
<5 |
Δ |
539 |
38 |
○ |
4039 |
⊚ |
○ |
118 |
20 |
○ |
544 |
34 |
○ |
4040 |
⊚ |
○ |
117 |
40 |
○ |
522 |
31 |
○ |
[Table 9]
No. |
machinability |
corrosion resistance |
hot workability |
mechanical properties |
stress resistance corrosion cracking resistance |
form of chippings |
condition of cut surface |
cutting force (N) |
maximum depth of corrosion (µm) |
700°C deformability |
tensile strength (N/mm2) |
elonga tion (%) |
4041 |
⊚ |
○ |
120 |
20 |
○ |
565 |
31 |
○ |
4042 |
⊚ |
○ |
119 |
<5 |
○ |
567 |
34 |
○ |
4043 |
⊚ |
○ |
121 |
<5 |
○ |
530 |
29 |
○ |
4044 |
⊚ |
○ |
120 |
<5 |
○ |
548 |
31 |
○ |
4045 |
⊚ |
○ |
121 |
<5 |
○ |
572 |
32 |
○ |
4046 |
⊚ |
○ |
119 |
<5 |
○ |
579 |
29 |
○ |
4047 |
⊚ |
○ |
123 |
<5 |
○ |
542 |
26 |
○ |
4048 |
⊚ |
○ |
123 |
<5 |
○ |
540 |
28 |
○ |
4049 |
⊚ |
○ |
120 |
<5 |
○ |
439 |
33 |
○ |
[Table 10]
No. |
machinability |
corrosion resistance |
hot work ability |
mechanical properties |
stress resistance corrosion cracking resistance |
high-temperature oxidation |
form of chipings |
condition of cut surface |
cutting force (N) |
maximum depth of corrosion (µm) |
700°C deforma bility |
tensile strength (N/mm2) |
elongation (%) |
increase in weight by oxidation (mg/10cm2) |
14001 |
○ |
○ |
103 |
1100 |
Δ |
408 |
37 |
xx |
1.8 |
14002 |
○ |
○ |
101 |
1000 |
x |
387 |
39 |
xx |
1.7. |
14003 |
○ |
Δ |
112 |
1050 |
○ |
414 |
38 |
xx |
1.7 |
14004 |
x |
○ |
223 |
900 |
○ |
438 |
38 |
x |
1.2 |
14005 |
x |
○ |
178 |
350 |
Δ |
735 |
28 |
○ |
0.2 |
14006 |
x |
○ |
217 |
600 |
○ |
425 |
39 |
x |
1.8 |
1. A lead-free, free-cutting copper alloy which comprises 70 to 80 percent, by weight,
of copper, 1.8 to 3.5 percent, by weight, of silicon; 0.02 to 0.25 percent, by weight,
of phosphorous; optionally at least one element selected from among 0.3 to 3.5 percent,
by weight, of tin and 1.0 to 3.5 percent, by weight, of aluminium, and/or optionally
least one element selected from among 0.02 to 0.4 percent, by weight, bismuth, 0.02
to 0.4 percent, by weight, of tellurium, and 0.02 to 0.4 percent, by weight, of selenium;
and the remaining percent, by weight, of zinc and wherein the metal structure of the
free cutting copper alloy has at least one phase selected from the γ (gamma) phase
and the κ (kappa) phase.
2. A lead-free cutting copper alloy according to claim 1 wherein when cut on a circumferential
surface by a lathe provided with a point nose straight tool at a rake angle of -8
(minus 8) and at a cutting rate of 50 m/min, a cutting depth of 1.5 mm, a feed rate
of 0.11 mm/rev yields chips having one or more shapes selected from the group consisting
of an arch shape and a fine needle shape.
3. A lead free, free-cutting copper alloy according to any one of the preceding claims
which is subjected to a heat treatment for 30 minutes to 5 hours at 400 to 600°C.
4. A method of forming a lead-fee, free cutting alloy having a metal structure which
has at least one phase selected from the γ (gamma) phase and the κ (kappa) phase which
comprises alloying copper, silicon, phosphorous and zinc in an amount of 70 to 80
percent, by weight, of copper,1.8 to 35 percent, by weight, of silicon; 0.02 to 0.25
percent, by weight, of phosphorus optionally alloying at least one element selected
from tin and aluminium in an amount of 0.3 to 3.5 percent, by weight, of tin and 1.0
to 3.5 percent, by weight, of aluminium, and for optionally alloying at least one
element selected from bismuth, tellurium and selenium in an amount of 0.02 to 0.4
percent, by weight, bismuth, 0.02 to 0.4 percent, by weight, of tellurium, and 0.02
to 0.4 percent, by weight, of selenium; optionally alloying at least one element selected
from bismuth, tellurium and selenium in an amount of 0.02 to 0.4 percent, by weight,
bismuth, 0.02 to 0.4 percent, by weight, of tellurium, and 0.02 to 0.4 percent, by
weight, of selenium; and the remaining percent by weight of zinc.
5. The method of any of claim 4 wherein said silicon is provided as a Cu-Si alloy.
6. The method of any one of claims 4 to 5 wherein said lead-free, free cutting alloy
is subjected to a heat treatment for 30 minutes to 5 hours at 400 to 600°C.
1. Bleifreie Kupfer-Automatenlegierung, welche 70 bis 80 Gewichtsprozent an Kupfer, 1,8
bis 3,5 Gewichtsprozent an Silikon, 0,02 bis 0,25 Gewichtsprozent an Phosphor, optional
mindestens ein Element, welches ausgewählt ist aus 0,3 bis 3,5 Gewichtsprozent an
Zinn und 1,0 bis 3,5 Gewichtsprozent an Aluminium, und/oder optional mindestens ein
Element, welches ausgewählt ist aus 0,02 bis 0,4 Gewichtsprozent an Wismut, 0,02 bis
0,4 Gewichtsprozent an Tellurium und 0,02 bis 0,4 Gewichtsprozent an Selen, und die
restlichen Gewichtsprozentanteile an Zink umfasst, wobei die Metallstruktur der Kupfer-Automatenlegierung
mindestens eine Phase aufweist, die ausgewählt ist aus der γ (gamma)-Phase und der
κ (kappa)-Phase.
2. Bleifreie Kupfer-Automatenlegierung nach Anspruch 1, wobei, wenn diese auf einer umlaufenden
Oberfläche mit einem Drehmeißel, der als gerades Werkzeug mit scharfer Spitze bereitgestellt
ist, mit einem Spanwinkel von -8 (minus 8) und einer Schnittrate von 50 m/min, einer
Schnitttiefe von 1,5 mm und einer Vorschubrate von 0,11 mm/U geschnitten wird, sich
Späne ergeben, welche eine oder mehrere Formen aufweisen, die ausgewählt sind aus
der Gruppe, die aus einer Bogenform und einer feinen Nadelform besteht.
3. Bleifreie Kupfer-Automatenlegierung nach einem der vorhergehenden Ansprüche, welche
für 30 Minuten bis zu 5 Stunden einer Hitzebehandlung bei 400 bis 600 °C unterzogen
ist.
4. Verfahren zur Bildung einer bleifreien Automatenlegierung mit einer Metallstruktur,
welche mindestens eine Phase aufweist, die aus der γ (gamma)-Phase und der κ (kappa)-Phase
ausgewählt ist, welche Legierungen aus Kupfer, Silikon, Phosphor und Zink in einer
Menge von 70 bis 80 Gewichtsprozent an Kupfer, 1,8 bis 3,5 Gewichtsprozent an Silikon,
0,02 bis 0,25 Gewichtsprozent an Phosphor, optional Legierungen mit mindestens einem
Element, welches ausgewählt ist aus Zinn und Aluminium in einer Menge von 0,3 bis
3,5 Gewichtsprozent an Zinn und 1,0 bis 3,5 Gewichtsprozent an Aluminium, und/oder
optional Legierungen mit mindestens einem Element, welches ausgewählt ist aus Wismut,
Tellurium und Selen in einer Menge von 0,02 bis 0,4 Gewichtsprozent an Wismut, 0,02
bis 0,4 Gewichtsprozent an Tellurium und 0,02 bis 0,4 Gewichtsprozent an Selen und
den restlichen Gewichtsprozentanteil an Zink umfasst.
5. Verfahren nach Anspruch 4, wobei das Silikon als eine Cu-Si-Legierung bereitgestellt
ist.
6. Verfahren nach einem der Ansprüche 4 bis 5, wobei die bleifreie Automatenlegierung
für 30 Minuten bis zu 5 Stunden einer Hitzebehandlung bei 400 bis 600 °C unterzogen
ist.
1. Alliage de cuivre de décolletage sans plomb, comprenant 70 à 80 pour cent en poids
de cuivre; 1,8 à 3,5 pour cent en poids de silicium; 0,02 à 0,25 pour cent en poids
de phosphore; optionnellement au moins un élément sélectionné parmi 0,3 à 3,5 pour
cent en poids d'étain et 1,0 à 3,5 pour cent en poids d'aluminium; et/ou optionnellement
au moins un élément sélectionné parmi 0,02 à 0,4 pour cent en poids de bismuth; 0,02
à 0,4 pour cent en poids de tellure et 0,02 à 0,4 pour cent en poids de sélénium;
et le pourcentage en poids restant étant constitué de zinc, et dans lequel la structure
de métal de l'alliage de cuivre de décolletage comprend au moins une phase sélectionnée
parmi la phase γ (gamma) et la phase κ (kappa).
2. Alliage de cuivre de décolletage sans plomb selon la revendication 1, dans lequel,
lorsque l'on coupe une surface circonférentielle à l'aide d'un tour formé par un outil
droit à nez pointu présentant un angle de coupe de -8 (moins 8), une vitesse de coupe
de 50 mètres par minute, une profondeur de coupe de 1,5 mm, et une vitesse de progression
de 0,11 millimètres par tour, on obtient des pièces présentant une ou plusieurs forme(s)
sélectionnée(s) dans le groupe comprenant la forme d'une arche et la forme d'une aiguille
fine.
3. Alliage de cuivre de décolletage sans plomb selon l'une quelconque des revendications
précédentes, qui est soumis à un traitement thermique d'une durée de 30 minutes à
5 heures à une température comprise entre 400°C et 600°C.
4. Procédé pour former un alliage de cuivre de décolletage sans plomb présentant une
structure de métal comprenant au moins une phase sélectionnée parmi la phase γ (gamma)
et la phase κ (kappa), comprenant l'alliage de cuivre, de silicium, de phosphore et
de zinc en des quantités de 70 à 80 pour cent en poids de cuivre; 1,8 à 3,5 pour cent
en poids de silicium; 0,02 à 0,25 pour cent en poids de phosphore; optionnellement
au moins un élément sélectionné parmi l'étain et l'aluminium en des quantités de 0,3
à 3,5 pour cent en poids d'étain et 1,0 à 3,5 pour cent en poids d'aluminium; et/ou
optionnellement au moins un élément sélectionné parmi le bismuth, le tellure et le
sélénium en des quantités de 0,02 à 0,4 pour cent en poids de bismuth; 0,02 à 0,4
pour cent en poids de tellure et 0,02 à 0,4 pour cent en poids de sélénium; et le
pourcentage en poids restant étant constitué de zinc.
5. Procédé selon la revendication 4, dans lequel ledit silicium est fourni sous la forme
d'un alliage Cu-Si.
6. Procédé selon l'une des revendications 4 ou 5, dans lequel ledit alliage de décolletage
sans plomb est soumis à un traitement thermique d'une durée de 30 minutes à 5 heures
à une température comprise entre 400°C et 600°C.