U.S. patent application number 13/823584 was filed with the patent office on 2013-07-18 for copper alloy.
The applicant listed for this patent is Thomas Helmenkamp, Uwe Quadfasel, Dirk Rode, Hark Schulze. Invention is credited to Thomas Helmenkamp, Uwe Quadfasel, Dirk Rode, Hark Schulze.
Application Number | 20130183194 13/823584 |
Document ID | / |
Family ID | 45606890 |
Filed Date | 2013-07-18 |
United States Patent
Application |
20130183194 |
Kind Code |
A1 |
Helmenkamp; Thomas ; et
al. |
July 18, 2013 |
Copper Alloy
Abstract
Alloys are demonstrated based on copper, which have additions of
manganese and sulfur and/or calcium as well as additional elements.
The copper alloys are free from tellurium and lead, and are
distinguished by high electrical conductivity and good
machinability.
Inventors: |
Helmenkamp; Thomas;
(Osnabrueck, DE) ; Rode; Dirk; (Osnabrueck,
DE) ; Quadfasel; Uwe; (Osnabrueck, DE) ;
Schulze; Hark; (Hasbergen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Helmenkamp; Thomas
Rode; Dirk
Quadfasel; Uwe
Schulze; Hark |
Osnabrueck
Osnabrueck
Osnabrueck
Hasbergen |
|
DE
DE
DE
DE |
|
|
Family ID: |
45606890 |
Appl. No.: |
13/823584 |
Filed: |
August 16, 2011 |
PCT Filed: |
August 16, 2011 |
PCT NO: |
PCT/DE2011/001598 |
371 Date: |
March 14, 2013 |
Current U.S.
Class: |
420/489 ;
420/493 |
Current CPC
Class: |
C22C 9/05 20130101; C22C
9/00 20130101; C22C 9/01 20130101 |
Class at
Publication: |
420/489 ;
420/493 |
International
Class: |
C22C 9/05 20060101
C22C009/05; C22C 9/01 20060101 C22C009/01; C22C 9/00 20060101
C22C009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 8, 2010 |
DE |
10 2010 038 060.1 |
Claims
1. An alloy based on copper, comprising: 0.05 to 0.80 wt. %
manganese (Mn), 0.10 to 0.80 wt. % sulfur (S), and a remainder
being copper (Cu) and unavoidable impurities.
2. The alloy based on copper as recited in claim 1, further
comprising at least one additional element selected from the group
consisting of: 0.002 to 0.05 wt. % phosphorus (P), 0.01 to 0.5 wt.
% chromium (Cr), 0.01 to 0.5 wt. % aluminum (Al), and 0.01 to 0.5
wt. % magnesium (Mg).
3. The alloy based on copper as recited in claim 1, wherein the
manganese proportion is from 0.10 to 0.30 wt. %.
4. The alloy based on copper as recited in claim 1, wherein the
manganese proportion is from 0.10 to 0.20 wt. %.
5. The alloy based on copper as recited in claim 2, wherein the
manganese proportion is from 0.10 to 0.30 wt. %.
6. The alloy based on copper as recited in claim 1, wherein the
sulfur proportion is from 0.20 to 0.60 wt. %.
7. The alloy based on copper as recited in claim 2, wherein the
sulfur proportion is from 0.20 to 0.60 wt. %.
8. The alloy based on copper as recited in claim 3, wherein the
sulfur proportion is from 0.20 to 0.60 wt. %.
9. An alloy based on copper, comprising: 0.30 to 1.50 wt. % calcium
(Ca), and a remainder being copper (Cu) and unavoidable
impurities.
10. The alloy based on copper as recited in claim 9, further
comprising at least one additional element selected from the group
consisting of: 0.005 to 0.05 wt. % manganese (Mn), 0.005 to 0.05
wt. % sulfur (S), 0.002 to 0.05 wt. % phosphorus (P), 0.01 to 0.5
wt. % chromium (Cr), 0.01 to 0.5 wt. % aluminum (Al), and 0.01 to
0.5 wt. % magnesium (Mg),
11. The alloy based on copper as recited in claim 9, wherein the
calcium proportion is from 0.5 to 1.0 wt. %.
12. The alloy based on copper as recited in claim 10, wherein the
calcium proportion is from 0.5 to 1.0 wt. %.
13. The alloy based on copper as recited in claim 1, having an
electrical conductivity of 35 to 55 MS/m.
14. The alloy based on copper as recited in claim 2, having an
electrical conductivity of 35 to 55 MS/m.
15. The alloy based on copper as recited in claim 9, having an
electrical conductivity of 35 to 55 MS/m.
16. The alloy based on copper as recited in claim 10, having an
electrical conductivity of 35 to 55 MS/m.
17. The alloy based on copper as recited in claim 1, having an
electrical conductivity from 48 to 53 MS/m.
18. The alloy based on copper as recited in claim 2, having an
electrical conductivity from 48 to 53 MS/m.
19. The alloy based on copper as recited in claim 1, having a
machinability index of 80% to 95%.
20. The alloy based on copper as recited in claim 2, having a
machinability index of 80% to 95%.
21. A semifinished material made of an alloy as recited in claim 1
in the form of a rolled product.
22. A semifinished material made of an alloy as recited in claim 2
in the form of a rolled product.
23. A semifinished material made of an alloy as recited in claim 1
in the form of an extruded/drawn product.
24. A semifinished material made of an alloy as recited in claim 2
in the form of an extruded/drawn product.
25. A semifinished material made of an alloy as recited in claim 1
in the form of a forged product.
26. A semifinished material made of an alloy as recited in claim 2
in the form of a forged product.
27. A semifinished material made of an alloy as recited in claim 1
in the form of a cast product.
28. A semifinished material made of an alloy as recited in claim 2
in the form of a cast product.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a copper alloy,
particularly a lead-free and tellurium-free copper alloy, as well
as semifinished products made of such a copper alloy.
[0003] 2. Description of the Related Art
[0004] In many fields of industry and technology, copper is an
indispensable material because of its natural qualities. Especially
when materials are required having the highest electrical and
thermal conductivity, copper and copper alloys are of great
importance. The use of pure copper, however, brings on difficulties
if parts are to be processed in a metal-cutting manner. The high
toughness of copper, which is particularly valued in chipless
shaping, proves to be a disadvantageous material property in this
instance. The cause for this is long chip formation, which impedes
the operating sequence during drilling and turning, and leads to
large wear of the cutting lips. On CNC-controlled, as well as on
usual automatic lathes, pure copper is normally workable or
processable only at uneconomically high costs in time, personnel
and tooling.
[0005] Machinable copper materials are known having admixtures of
lead, bismuth, sulfur or tellurium. As early as in U.S. Pat. No.
1,959,509 the favorable influence of alloying bismuth on the
machinability of copper alloys was explained. The advantageous
properties of tellurium in copper alloys may be seen in U.S. Pat.
No. 2,027,807.
[0006] Lead and bismuth act as chip breakers in metallic form,
sulfur and tellurium, on the other hand, act as an intermetallic
phase in the form of copper sulfide (Cu.sub.2S) or copper telluride
(Cu.sub.2Te). However, the low melting points of lead and bismuth
restrict the hot ductility considerably, for instance, by
extrusion, so that economical processability on conventional
production devices cannot be taken for granted, or only in a
limited way. In addition, there are health-related and
environmentally hazardous considerations with respect to lead in
copper alloys.
[0007] On the other hand, copper materials having the addition of
sulfur or tellurium in the form of CuSP or CuTeP stand out by
having a favorable combination of good machinability as well as a
very high electrical and thermal conductivity. However, tellurium
is particularly limited in its availability as a result of raw
material scarcity, and is comparatively costly. Therefore, in
response to an increasing resource scarcity of tellurium, an
alternative would be desirable.
DESCRIPTION OF THE INVENTION
[0008] Accordingly, it is an object of the present invention to
provide a copper alloy which, compared to the known copper alloys
CuTeP and CuSP, has a machinability as well as cold-formability and
hot ductility that is at least equal or better.
[0009] The objective is first attained, according to the present
invention, claims 1-8, by an alloy based on copper, consisting of:
[0010] 0.05 to 0.80 wt. % manganese (Mn), [0011] 0.10 to 0.80 wt. %
sulfur (S), [0012] optionally one or more elements selected from
the group made up of [0013] 0.002 to 0.05 wt. % phosphorus (P),
[0014] 0.01 to 0.5 wt. % chromium (Cr), [0015] 0.01 to 0.5 wt. %
aluminum (Al), [0016] 0.01 to 0.5 wt. % magnesium (Mg), [0017] and
[0018] the remainder being copper (Cu) and unavoidable
impurities.
[0019] A copper alloy is proposed, in accordance with the present
invention, based on copper having the addition of manganese and
sulfur, as well as accompanying elements, which can do without lead
or tellurium, but demonstrates good machinability.
[0020] The copper alloy consists of copper, which has as alloying
components 0.05 to 0.80 wt. % manganese (Mn), 0.10 to 0.80 wt. %
sulfur (S), and optionally one or more elements selected from the
group made up of 0.002 to 0.05 wt. % phosphorus (P), 0.01 to 0.05
wt. % Chromium (Cr), 0.01 to 0.5 wt. % aluminum (Al), 0.01 to 0.5
wt. % magnesium (Mg), besides unavoidable impurities.
[0021] A mixed phase, consisting of copper sulfide (Cu.sub.2S) and
manganese sulfide (MnS) acts as chip breaker in the CuSMn alloy
according to the present invention.
[0022] Especially preferred, the manganese proportion amounts to
0.10 to 0.20 wt. %. Also preferred, there is a sulfur proportion,
that is between 0.20 to 0.60 wt. %.
[0023] The object on which the present invention is based is
furthermore attained by an alloy based on copper according to
claims 9-12. It consists of 0.30 to 1.50 wt. % calcium (Ca),
optionally one or more elements selected from the group which
consists of 0.005 to 0.05 wt. % manganese (Mn), 0.005 to 0.05 wt. %
sulfur (S), 0.002 to 0.05 wt. % phosphorus (P), 0.01 to 0.5 wt. %
chromium (Cr), 0.01 to 0.5 wt. % aluminum (Al), 0.01 to 0.5 wt. %
magnesium (Mg), as well as the remainder copper (Cu) and
unavoidable impurities.
[0024] The calcium proportion in the previous copper alloy is
preferably between 0.5 to 1.0 wt. %.
[0025] In the CuCa alloy, the forming eutectic phase Cu.sub.5Ca
acts as a chip breaker.
[0026] Phosphorus is used as a deoxidizer, which binds the free
oxygen dissolved in the melt to itself, and thus avoids gas bubbles
(hydrogen disease) and the oxidation of alloy components. Moreover,
phosphorus is added to improve the flowing properties of the copper
alloy during casting.
[0027] Manganese refines the grain and, in combination with sulfur,
improves the machinability.
[0028] Aluminum increases the hardness and yield strength without
reducing the toughness. Aluminum is an element which improves the
strength, machinability and resistance to abrasion, as well as the
resistance to oxidation at high temperatures.
[0029] Chromium and manganese are used to improve the resistance to
oxidation at high temperatures. In this instance, particularly good
results are obtained if they are mixed with aluminum, so as to
achieve a synergy effect.
[0030] The two copper materials CuSMn and CuCa proposed in the
present invention have a machinability which is equal to or better
than that of CuSP. During experiments, a machinability index of 90%
was ascertained for CuSMn, 86% for CuCa and 76 and 79% for the
reference materials CuTeP and CuSP.
[0031] The materials have an electric conductivity that is between
35 and 55 MS/m, particularly in a range of 48 to 53 MS/m.
Furthermore, the copper alloys proposed in the present invention
are free from toxic alloying elements and are cost-effective, since
the alloying elements are available cost-effectively. In addition,
we should emphasize the importance of the scraps being reusable. A
special criterion of the two proposed copper alloys is that
workability using conventional production and processing machines
is possible, and in particular, the alloys have both a sufficient
cold-formability and also a very good hot ductility.
[0032] Therefore, using the proposed copper alloys, semifinished
products in the form of rolled products, extruded/drawn products,
forged products or cast products are made available.
Exemplary Embodiments and Comparative Observations
[0033] With the aid of two exemplary embodiments, let us explain
the advantageous properties according to the present invention of
the new lead-free and tellurium-free alloys, as compared to the
known and standardized materials CuTeP (=EN alloy CW118C, ASTM
alloy C14500) and CuSP (=EN alloy CW114C, ASTM alloy C14700).
[0034] In a crucible induction furnace, CuSMn, CuCa and the
reference materials CuTeP and CuSP respectively were melted and
cast to extrusion billets in a continuous casting method. The
composition of the materials is reproduced in Table 1. The
composition of CuSMn corresponds to claims 1-8, CuCa fulfills
claims 9-12. The composition of the reference materials CuTeP and
CuSP corresponds to the specifications of EN and ASTM. The
continuously cast round billets were extruded in an extruding press
at a heating-up temperature of 850.degree. C. without problems to
bars and were subsequently drawn at a cross sectional reduction of
10 to 15% to a final diameter of 35 mm. Having the cross sectional
reduction of 10 to 15%, the most frequently supplied temper R250
for machinable copper according to EN 12164 or H02 according to
ASTM B301 is achieved. Table 2 shows characteristic mechanical
properties and the Brinell hardness and specific electrical
conductivity of the bars in the finished drawn temper. The test
results show, that the new materials according to the present
invention, using the standard materials CuTeP and CuSP have
comparable mechanical characteristics and an equally good
electrical conductivity as the standard materials CuTeP and CuSP.
Material CuSMn, based on the even more favorable strength/fracture
elongation combination compared to standard material CuSP, still
has the advantage of better cold-formability (e.g. for producing
"hammered" torch tips).
[0035] Machinability Investigations
[0036] With regard to the bars listed in Table 2, comparative
machinability tests in the form of drilling tests were carried out.
Processing by drilling was given the advantage over processing by
turning or thread cutting, because the production of small bores
(such as in torch lips) represents the most difficult chip-cutting
processing form. If a material demonstrates positive results in
this instance, processing by turning or thread-cutting will also
not represent a problem.
[0037] For the drilling tests, the following parameters were used,
that are usual in modern processing machines: [0038] drilling tool:
2 mm .PHI. hard metal drill having inner cooling [0039] tip coated
with AlTiN [0040] type Guhring WNRN15XD [0041] drilling strategy:
at end face apply 45 bores into bar sections: [0042] cutting speed:
100 m/min [0043] feed function: 0.04 mm/revolution [0044] drilling
depth 33 mm [0045] inner cooling drill: emulsion 40 bar
[0046] The following were valued: [0047] the chip form in
accordance with steel test sheet 1178-90 [0048] the average chip
mass via weight measurement of 100 chips each [0049] tool wear as
flank wear after 270 bores [0050] required average feed function
force [0051] bore quality in the light of criteria: [0052]
cylindricity (conicity) of bore over the length [0053] roundness of
the bore over the circumference [0054] diameter deviation over the
length [0055] roughness R.sub.2 of the boring surface
[0056] In order to make possible a quantitatively comparative
valuation of the materials to the reference materials, the single
measurement results were valued using a point system of 0 to 10
points, 0 points meaning extremely bad and 10 points meaning
optimal=very good.
[0057] The individual valuations were added, a maximum of 80 points
being achievable. This overall valuation of the machinability shall
be defined here as machinability index, where 80 points then
correspond to a maximum achievable machinability index of 100%. The
results of these investigations are listed in table 3. The new
materials according to the present invention, CuCa and CuSMn, in
comparison to the reference materials, achieve the following
machinability indices:
[0058] CuSMn: 90%
[0059] CuCa: 86%
[0060] CuTeP: 76%
[0061] CuSP: 79%
[0062] To clarify the good brittle machinability of all materials,
FIG. 1 shows the drilling chips from the machinability
investigations. The somewhat longer helical chip pieces occur only
sporadically. The very thorough and effortful machinability
investigations have shown that the materials according to the
present invention are at least equivalent in machinability to
reference materials CuSP and CuTeP that have been available up to
now, or even have slight advantages.
[0063] In careful investigations, the inventors have created a
copper material which supplements the current selection of
available like with CuTeP and CuSP, and which has the following
quality features: [0064] machinability equal to or better than
CuTeP/CuSP; [0065] electrical conductivity .gtoreq.35 MS/m; [0066]
free from toxic alloying elements; [0067] cost-effective
availability of the alloying elements; [0068] reusability of the
scrap; [0069] processability using conventional production steps
and machines.
[0070] In the investigations, each alloying element aluminum (Al),
calcium (Ca), cobalt (Co), chromium (Cr), iron (Fe), magnesium
(Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), tin (Sn) and
zinc (Zn) was tested in combination with sulfur (S) and calcium
(Ca) as a single addition to copper with respect to the achievable
electrical conductivity and machinability. The well-established
materials CuSP and CuTeP were used as comparative samples for the
machinability tests. Qualitatively valued was the shape of the
chips during the drilling of 3 mm holes and the appearance of drill
fractures.
[0071] The desired material properties or property combinations
were achieved by alloying manganese, specifically in a proportion
of 0.05 to 0.80 wt. %, preferably 0.10 to 0.30 wt. %, particularly
0.10 to 0.20 wt. %, as well as sulfur in a proportion of 0.10 to
0.80 wt. %, particularly 0.20 to 0.60 wt. %.
[0072] Moreover, it could be determined that the desired material
properties in an alloy based on copper could be achieved, which
contains as an alloy component calcium having a proportion of 0.30
to 1.50 wt. %, preferably between 0.5 and 1.0 wt. %.
[0073] It was recognized as essential to the present invention that
the two copper materials CuSMn and CuCa that were pointed out have
the aforementioned independent chip-breaking phases, namely the
mixed phase consisting of Cu.sub.2S and MnS and the eutectic phase
Cu.sub.5Ca.
[0074] In the processing and testing of material samples of the
copper alloys according to the present invention, it was shown that
particularly the alloy CuSMn had a hot ductility and cold
formability that was comparable to, or even slightly better than
copper alloy CuSP or copper alloy CuTeP.
TABLE-US-00001 TABLE 1 Composition of the Materials CuSMn, CuCa
According to the present Invention and the Reference Materials
CuTeP and CuSP Composition in wt. % Unavoidable Material Cu Te S Mn
Ca P impurities CuSMn 99.50 / 0.30 0.18 / 0.007 0.01 CuCa 99.22 /
0.005 0.007 0.73 0.02 0.02 CuTeP 99.53 0.44 / / / 0.007 0.02
Setpoint balance 0.4-0.7 / / / 0.003- .ltoreq.0.1 values EN- 0.012
CW118C Setpoint +Te .gtoreq. 99.90 0.40-0.7 / / / 0.004- / values
ASTM- 0.012 C14500 CuSP 99.65 / 0.31 / / 0.005 0.03 Setpoint
balance / 0.2-0.7 / / 0.003- .ltoreq.0.1 values EN- 0.012 CW114C
Setpoint +S .gtoreq. 99.90 / 0.20-0.50 / / 0.002- / values ASTM-
0.005 C14700
TABLE-US-00002 TABLE 2 Mechanical and Technological Properties of
the Materials CuSMn and CuCa According to the Present Invention and
Reference values of CuTeP und CuSP in the Drawn Half-hard Temper
(R250 According to EN 12164 and Temper H02 According to ASTM B301)
Tensile 0.2% Yield Elongation Brinell Specific el. conductivity
strength Strength after Fracture hardness in soft temper at
20.degree. C. Material R.sub.m (MPa) R.sub.p0.2 (MPa) A (%)
HBW2.5/62.5 (MS/m) (% IACS) CuSMn 265 245 20 85 53.0 91.5 CuCa 269
261 13 97 52.5 90.5 CuTeP 286 257 18 88 53.0 91.5 CuSP 269 263 14
85 52.5 90.5 Setpoint .gtoreq.250 ~200 .gtoreq.7 ~90 / / values for
CuTeP + CuSP: EN 12164 R250 Setpoint .gtoreq.260 .gtoreq.205.sup.1)
.gtoreq.12 / / CuTeP .gtoreq. 85.0 values for .sup.1) 0.5% CuSP
.gtoreq. 90.0 C14500 + Yield C14700 strength ASTM B301 under load
HO2
TABLE-US-00003 TABLE 3 Results of Machinability Investigations
(including valuation) Drilling quality Roundness Machin- (diameter
ability Average deviation Diameter Overall index in Flank wear feed
Cylindricity over the deviation Rough- valua- % Average after 270
function (conicity of circum- over the ness tion (80 P = chip mass
bores force the bore) ference) length R.sub.z Sum 100%) Material
Chip type .mu.g .mu.m N .mu.m .mu.m .mu.m .mu.m points % CuSMn
Spiral chips, 90 20 40 20 5 0 1 (72) 90 spiral chip (8 P) (8 P) (9
P) (9 P) (10 P) (10 P) (10 P) pieces helical chip pieces (8 P) CuCa
Discontinuous 50 17 70 10 5 0 3 (69) 86 chips (10 P) (10 P) (10 P)
(4 P) (10 P) (10 P) (10 P) (5 P) CuTeP Spiral chips, 110 20 35 50
10 20 1 (61) 76 spiral chip (8 P) (8 P) (10 P) (6 P) (5 P) (6 P)
(10 P) pieces helical chip pieces (8 P) CuSP Spiral chips, 90 28 50
30 5 10 1 (63) 79 spiral chip (8 P) (4 P) (7 P) (8 P) (10 P) (8 P)
(10 P) pieces helical chip pieces (8 P) drill fractures did not
occur with any material
* * * * *