U.S. patent application number 16/623001 was filed with the patent office on 2021-05-13 for titanium-containing zinc wrought alloy.
The applicant listed for this patent is Grillo-Werke AG. Invention is credited to Jan Huttig, Armin Melzer, Frank Prenger, Didier Rollez, Markus van Wesel, Joanna von Kries, Jurgen Wisniewski.
Application Number | 20210140014 16/623001 |
Document ID | / |
Family ID | 1000005357103 |
Filed Date | 2021-05-13 |
![](/patent/app/20210140014/US20210140014A1-20210513\US20210140014A1-2021051)
United States Patent
Application |
20210140014 |
Kind Code |
A1 |
Huttig; Jan ; et
al. |
May 13, 2021 |
TITANIUM-CONTAINING ZINC WROUGHT ALLOY
Abstract
The present invention relates to a zinc wrought alloy with
improved machinability as compared to known wrought alloys, as well
as semifinished products, forgings, turned parts, locks, screw
connections, locking cylinders, sleeves, fittings, pressed parts,
pneumatic parts, hydraulic parts, mountings, valves and ball valves
that comprise a zinc wrought alloy according to the invention.
Inventors: |
Huttig; Jan; (Duisburg,
DE) ; Melzer; Armin; (Duisburg, DE) ; Prenger;
Frank; (Duisburg, DE) ; Rollez; Didier;
(Duisburg, DE) ; van Wesel; Markus; (Duisburg,
DE) ; von Kries; Joanna; (Hittbergen, DE) ;
Wisniewski; Jurgen; (Duisburg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Grillo-Werke AG |
Duisburg |
|
DE |
|
|
Family ID: |
1000005357103 |
Appl. No.: |
16/623001 |
Filed: |
July 2, 2018 |
PCT Filed: |
July 2, 2018 |
PCT NO: |
PCT/EP2018/067808 |
371 Date: |
December 16, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22C 18/04 20130101 |
International
Class: |
C22C 18/04 20060101
C22C018/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 4, 2017 |
EP |
17179643.6 |
Claims
1. A zinc wrought alloy having an Al content of from 5% by weight
to 18% by weight, a Cu content of from 0.1% by weight to 4% by
weight, an Mg content of from 0.001% by weight to 0.05% by weight,
a Ti content of from 0.01% by weight to 1% by weight, wherein Zn is
the balance to 100%, and wherein the alloy may contain impurities
at a proportion of 0.07% by weight or less.
2. The zinc wrought alloy according to claim 1, characterized in
that lead is not alloyed.
3. The zinc wrought alloy according to claim 1, characterized in
that the content of Al is from 8% to 16% by weight.
4. The zinc wrought alloy according to claim 1, characterized in
that the content of Ti is from 0.03% to 1% by weight.
5. The zinc wrought alloy according to claim 1, characterized in
that the content of Cu is from 0.1% to 2.5% by weight.
6. The zinc wrought alloy according to claim 1, characterized in
that the content of Mg is from 0.003% by weight to 0.05% by
weight.
7. The zinc wrought alloy according to claim 1, characterized by
containing silicon as an impurity.
8. The zinc wrought alloy according to claim 1, having an Al
content from 5% to 9% by weight, a Cu content from 0.5% to 2.5% by
weight, a magnesium content from 0.003% to 0.05% by weight, a
titanium content from 0.05% to 1% by weight, with zinc as the
balance to reach 100% by weight.
9. The zinc wrought alloy according to claim 1, having an Al
content from 5% to 9% by weight, a Cu content from 0.5% to 1.5% by
weight, an Mg content from 0.003% to 0.05% by weight, a Ti content
from 0.05% to 1% by weight, with zinc as the balance to reach 100%
by weight.
10. The zinc wrought alloy according to claim 1, having an Al
content from 10% to 12% by weight, a Cu content from 0.5% to 2.5%
by weight, an Mg content from 0.003% to 0.05% by weight, a Ti
content from 0.05% to 1% by weight, with zinc as the balance to
reach 100% by weight.
11. The zinc wrought alloy according to claim 1, having an Al
content from 10% to 12% by weight, a Cu content from 0.5% to 1.5%
by weight, an Mg content from 0.003% to 0.05% by weight, a Ti
content from 0.05% to 1% by weight, with zinc as the balance to
reach 100% by weight.
12. The zinc wrought alloy according to claim 1, having an Al
content from 14% to 16% by weight, a Cu content from 0.5% to 2.5%
by weight, an Mg content from 0.003% to 0.05% by weight, a Ti
content from 0.05% to 1% by weight, with zinc as the balance to
reach 100% by weight.
13. The zinc wrought alloy according to claim 1, having an Al
content from 14% to 16% by weight, a Cu content from 0.5% to 1.5%
by weight, an Mg content from 0.003% to 0.05% by weight, a Ti
content from 0.05% to 1% by weight, with zinc as the balance to
reach 100% by weight.
14. The zinc wrought alloy according to claim 1, having an Al
content from 16% to 18% by weight, a Cu content from 0.5% to 2.5%
by weight, a magnesium content from 0.001% to 0.05% by weight, a
titanium content from 0.05% to 1% by weight, with zinc as the
balance to reach 100% by weight.
15. The zinc wrought alloy according to claim 1, having an Al
content from 16% to 18% by weight, a Cu content from 0.5% to 1.5%
by weight, a magnesium content from 0.001% to 0.05% by weight, a
titanium content from 0.05% to 1% by weight, with zinc as the
balance to reach 100% by weight.
16. An object of manufacture comprising the zinc wrought alloy
according to claim 1, the object of manufacture being a
semifinished product and/or article.
17. The object of manufacture according to claim 16, wherein said
semifinished product is a billet, an extruded section, a drawn
section, a wire, a strip, a powder, or a pressure die-cast
alloy.
18. The object of manufacture according to claim 16, wherein said
article is a forging, turned part, lock, screw connection, locking
cylinder, sleeve, fitting, pressed part, pneumatic part, hydraulic
part, mounting, valve or ball valve.
19. The object of manufacture of claim 16 being one of semifinished
products, forgings, turned parts, locks, screw connections, locking
cylinders, sleeves, fittings, pressed parts, pneumatic parts,
hydraulic parts, mountings, valves and ball valves.
20. A process for preparing and/or reshaping and/or processing
semifinished products, forgings, turned parts, locks, screw
connections, locking cylinders, sleeves, fittings, pressed parts,
pneumatic parts, hydraulic parts, mountings, valves and ball valves
according to claim 19 by cold or hot reshaping.
21. The process according to claim 20, characterized in that said
processing includes processing by forging or machining, especially
turning, drilling, milling, broaching, sawing, grinding or honing.
Description
[0001] The present invention relates to a zinc wrought alloy with
improved machinability as compared to known wrought alloys, as well
as semifinished products, forgings, turned parts, locks, screw
connections, locking cylinders, sleeves, fittings, pressed parts,
pneumatic parts, hydraulic parts, mountings, valves and ball valves
that comprise a zinc wrought alloy according to the invention.
[0002] A wide variety of copper-zinc alloys (brass alloys) are
known in the prior art. When objects are prepared from these
alloys, they are processed with shaping, for example, by machining.
Thus, machinability, i.e., the property of a material to be
processable by machining, is an important characteristic of
corresponding materials. To improve their machinability, brass
alloys are often alloyed with lead, such as free-machining brass,
CuZn39Pb3.
[0003] In recent years, the conditions to be met for the protection
of health and environment have been tightened up significantly by
the legislation in many fields. This affects, in particular, a ban
or a drastic reduction of lead as an alloy component in copper
alloys (see, for example, [1] Verordnung zur Novellierung der
Trinkwasserverordnung vom 21. Mai 2001, German Federal Law Gazette,
Issue 2001, Part I No. 24, issued in Bonn on May 28, 2001; [2]
Directive 2000/53/EC of the European Parliament and of the Council
of Sep. 18, 2000, on end-of-life vehicles, Official Journal of the
European Communities, L 269/34, DE, Oct. 21, 2000; or [3] Directive
2002/95/EC of the European Parliament and of the Council of Jan.
27, 2003, on the restriction of the use of certain hazardous
substances in electrical and electronic equipment, Official Journal
of the European Union, Feb. 13, 2003, DE, L 37/19). Therefore, in
view of these conditions to be met, low-lead brass alloys were
developed, but which can still contain up to 0.25% lead.
[0004] In addition to brass alloys, zinc alloys have also been
described in the prior art. Herein, low lead or even lead-free
alloys are increasingly being developed. As an example, EP 2675971
A--"Accessory consisting of a lock accessory" may be mentioned. It
discloses a zinc alloy with an Al content of from 13 to 25%, a Cu
content of from 0.2 to 3.5%, and an Mg content of less than 0.1%,
which is employed for lock accessories.
[0005] EP 2 385 148 A--"Zinc alloy with high creep resistance"
relates to a zinc-aluminum alloy with an Al content of 10 to
<25%, a Cu content of 0.05 to 3%, an Mg content of from 0.001 to
0.1%, an Mn content of 0.05% to 1.0% and an Si content of from 0.05
to 1%. The disclosed alloy has a high creeping resistance and is
suitable for the furnace brazing and normal brazing of heat
exchangers.
[0006] U.S. Pat. No. 3,734,785--"Zinc forging alloy" claims a
zinc-based alloy with an Al content of 9 to 22%, a Cu content of
0.5 to 1.5%, and an Mg content of 0.01 to 0.03%, which is
particularly suitable for hot formability.
[0007] U.S. Pat. No. 3,880,679--"Method of forming zinc-aluminum
alloys with good machinability" describes zinc-aluminum alloys with
an Al content of 22 to 27%, a Cu content of 0 to 10%, an Mg content
of 0.01 to 1%, and a Bi content of 0.01 to 3%.
[0008] EP 0 679 198 A--"Method for producing Zn--Al--Cu alloy
articles by centrifugal or die casting" describes a zinc alloy with
an Al content of 6.0 to 8.0%, a Cu content of 3.2 to 4.3%, for
preparing articles by centrifugal casting in a rubber mold, or
pressure die-casting in a metal mold.
[0009] Also widely known are zinc pressure die-casting alloys, also
referred to as ZAMAK.RTM.. These consist of
zinc-aluminum-copper-magnesium alloys, which cannot have the
corresponding strength properties, however. Further, machining is
clearly more problematic in zinc pressure die-casting alloys
because of the higher porosity structure.
[0010] Proceeding from this prior art, it has been the object of
the present invention to provide a zinc-based wrought alloy having
an improved machinability as compared to the prior art. At the same
time, the mechanical properties should not be adversely affected.
The improved machinability is to be achieved without including lead
in the alloy. Surprisingly, it has been found that titanium enables
an improved machinability of zinc wrought alloys. "Alloying"
basically means the preparation of an alloy by melting a metal
together with at least one other metal or non-metal. If in the
present application it is referred to the fact that a metal or
non-metal is not alloyed to an alloy, this means that the metal or
non-metal in question is not actively added.
[0011] Therefore, in a first embodiment, the object of the present
invention is achieved by a zinc wrought alloy having an Al content
of from 5% by weight to 18% by weight, a Cu content of from 0.1% by
weight to 4% by weight, an Mg content of from 0.001% by weight to
0.05% by weight, a Ti content of from 0.01% by weight to 1% by
weight, wherein Zn is the balance to 100%, and wherein the alloy
may contain impurities at a proportion of 0.07% by weight or
less.
[0012] This may be achieved, for example, by purposefully alloying
with titanium in zinc-aluminum-copper-magnesium alloys, which may
then be used in the preparation of a wide variety of semifinished
products and articles, such as forgings, turned parts, locks, screw
connections, locking cylinders, sleeves, fittings, pressed parts,
pneumatic parts, hydraulic parts, mountings, valves or ball valves.
Titanium is an extremely effective alloy element, strongly
affecting the microstructure already in the ppm range because of
its lattice structure. With it, a better machinability can be
achieved. At the same time, the mechanical properties of the alloy
are not adversely affected. Further, the zinc alloy according to
the invention has very good hot formability properties.
[0013] If percentages are stated with respect to components
contained in the alloy in the present application, they are percent
by weight unless explicitly stated otherwise, respectively based on
the total weight of the alloy. In particular, no further metals in
addition to the metals mentioned are alloyed with the alloy when it
is prepared. More preferably, the alloy according to the invention
is free of zirconium.
[0014] Surprisingly, it has been found that an improved
machinability, in particular, is achieved by selectively alloying
titanium. Other zinc wrought alloys (as disclosed, for example, in
EP 2675971--"Accessory consisting of a lock accessory") have a
poorer machinability (chip formation). Surprisingly, the machining
index could be brought into the reference range of free-machining
brass (CuZn39Pb3) by alloying with titanium, but without having to
alloy with lead. In addition, very good drilling, milling and
broaching properties are obtained. Further, processing may be dry
or wet. Alloying with lead is not necessary. Preferably, lead is
not alloyed. Preferred is a Pb content in the alloy according to
the invention of 0.003% by weight, especially <0.003% by weight,
which is present in the alloy as an impurity of zinc, in
particular, but not as an additional alloy component.
[0015] In addition, surprisingly, the microstructure (fineness of
grain) can be influenced by alloying with titanium so that the
forgeability is significantly improved. The proportion of titanium
(Ti) in the alloy according to the invention is preferably from
0.01% to 1% by weight, especially from 0.03% to 1% by weight,
specifically from 0.05% to 1% by weight, preferably from 0.06% to
1% by weight. It has been found that these proportions of titanium
are sufficient to achieve the improved properties. Larger amounts
are not necessary and also can be introduced only with difficulty
without adversely affecting the microstructure of the alloy.
Particularly preferred is a Ti content of from 0.05% to 1% by
weight.
[0016] In addition to the mentioned components (Zn, Al, Cu, Mg,
Ti), the alloy according to the invention may also comprise
impurities resulting from the fact that these components (Zn, Al,
Cu, Mg, Ti) are derived from recycling. However, for the usual
sources of the components (Zn, Al, Cu, Mg, Ti), these are not
critical. Common impurities are Cd, Pb, Sn and/or Fe. Preferably,
these impurities are contained only in very small amounts, so that
they do not affect the properties of the alloy according to the
invention. Therefore, preferred is a Pb content of <0.003% by
weight, and/or a Cd content of <0.003% by weight, especially
<0.0005% by weight, and/or an Sn content of <0.001% by
weight, especially of <0.0005% by weight, and/or an Fe content
of <0.05% by weight. Preferably, the content of all stated
impurities is below the mentioned values. Preferably, the content
of all impurities is 0.07% by weight or less.
[0017] The alloys according to the invention are suitable for
surface treatments (for example, electroplating, PVD, CVD,
passivation, painting, cathodic dip painting/coating, powder
coating).
[0018] Particularly preferred is a zinc wrought alloy with a
content of aluminum (Al) of from 5% by weight to 18% by weight,
especially from 8% to 18% by weight, preferably from 10% to 16% by
weight, more preferably from 5% to 9% by weight, preferably from
10% to 12% by weight, more preferably from 14% to 16% by weight,
especially from 16% to 18% by weight. These ranges are preferred
because all alloys are supereutectic therein, and there is a first
beta phase in the crystal structure. This beta phase is preferred
because it recrystallizes at room temperature very slowly (>10
years), so that the properties of the alloy are retained.
[0019] Particularly preferred is a zinc wrought alloy with a
content of copper (Cu) of from 0.1% to 2.5% by weight, especially
from 0.5 to 1.5% by weight. This range is preferred to achieve the
maximum mechanical strength, and to avoid the risk of forming of a
brittle epsilon phase in the crystal structure.
[0020] Particularly preferred is a zinc wrought alloy with a
content of magnesium (Mg) of from 0.003% by weight to 0.05% by
weight, especially from 0.003% to 0.03% by weight. This range
serves as a precaution to prevent intercrystalline corrosion by the
residual traces of impurities.
[0021] The titanium content of at most 1% in the zinc alloy is
limited by the solubility of titanium.
[0022] The zinc wrought alloy according to the invention may
further contain silicon as an impurity. If it contains silicon, the
content of silicon in the alloy is within a range of from 0.005% by
weight to 0.02% by weight, in particular. The silicon content is
determined by the selection of Al, because silicon is an impurity
in aluminum.
[0023] It has been found that an alloy having an Al content of from
10% to 12% by weight, a Cu content of from 0.5% by weight to 1.5%
by weight, an Mg content of from 0.003% by weight to 0.05% by
weight, a Ti content of from 0.05% to 1% by weight, with zinc as
the balance to reach 100% by weight, has particularly good
properties with respect to machinability. At the same time,
mechanical properties, such as strength or hardness, are not
adversely affected. Therefore, such an alloy is preferred.
[0024] Particularly preferred according to the invention is a zinc
wrought alloy with an Al content of from 14% to 16% by weight, a Cu
content of from 0.5% by weight to 1.5% by weight, an Mg content of
from 0.003% by weight to 0.05% by weight, a Ti content of from
0.05% to 1% by weight, with zinc as the balance to reach 100% by
weight. Corresponding alloys have good properties with respect to
machinability and in addition have a good processability. Herein,
mechanical properties of the alloy, such as strength or hardness,
are not adversely affected.
[0025] Further preferred alloys have the following compositions:
[0026] aluminum content of from 5% to 9% by weight, copper content
of from 0.5% to 2.5% by weight, magnesium content of from 0.003% to
0.05% by weight, titanium content of from 0.05% to 1% by weight,
with zinc as the balance to reach 100% by weight; [0027] aluminum
content of from 5% to 9% by weight, copper content of from 0.5% to
1.5% by weight, magnesium content of from 0.003% to 0.05% by
weight, titanium content of from 0.05% to 1% by weight, with zinc
as the balance to reach 100% by weight; [0028] aluminum content of
from 10% to 12% by weight, copper content of from 0.5% to 2.5% by
weight, magnesium content of from 0.003% to 0.05% by weight,
titanium content of from 0.05% to 1% by weight, with zinc as the
balance to reach 100% by weight; [0029] aluminum content of from
10% to 12% by weight, copper content of from 0.5% to 1.5% by
weight, magnesium content of from 0.003% to 0.05% by weight,
titanium content of from 0.05% to 1% by weight, with zinc as the
balance to reach 100% by weight; [0030] aluminum content of from
14% to 16% by weight, copper content of from 0.5% to 2.5% by
weight, magnesium content of from 0.003% to 0.05% by weight,
titanium content of from 0.05% to 1% by weight, with zinc as the
balance to reach 100% by weight; [0031] aluminum content of from
14% to 16% by weight, copper content of from 0.5% to 1.5% by
weight, magnesium content of from 0.003% to 0.05% by weight,
titanium content of from 0.05% to 1% by weight, with zinc as the
balance to reach 100% by weight; [0032] aluminum content of from
16% to 18% by weight, copper content of from 0.5% to 2.5% by
weight, magnesium content of from 0.001% to 0.05% by weight,
titanium content of from 0.05% to 1% by weight, with zinc as the
balance to reach 100% by weight; [0033] aluminum content of from
16% to 18% by weight, copper content of from 0.5% to 1.5% by
weight, magnesium content of from 0.001% to 0.05% by weight,
titanium content of from 0.05% to 1% by weight, with zinc as the
balance to reach 100% by weight.
[0034] The present invention further relates to the use of the
titanium-containing zinc wrought alloy according to the invention
for preparing semifinished products and articles with improved
machining properties. Further included according to the invention
is a semifinished product or article obtainable by processing the
zinc wrought alloy according to the invention. This semifinished
product may be, in particular, a billet, an extruded section, a
drawn section, a wire, a strip, a powder, or a pressure die-cast
alloy. In particular, the article may be a forging, turned part,
lock, screw connection, locking cylinder, sleeve, fitting, pressed
part, pneumatic part, hydraulic part, mounting, valve or ball
valve.
[0035] The semifinished product according to the invention,
especially the billet, can be prepared, for example, by casting the
zinc wrought alloy according to the invention into a mold. When the
alloy according to the invention has been formed into a billet
shape, for example, a section can be prepared therefrom by
reshaping by means of extrusion. Further, the zinc wrought alloy
according to the invention can be processed by different reshaping
methods. Such reshaping methods include, in particular, rolling,
forging, drawing. The articles according to the invention are
excellently suitable for being subjected to machining methods.
[0036] The zinc wrought alloy according to the invention and the
articles prepared therefrom exhibit an improved machinability as
compared to conventional ZnAl/ZnAlCu/ZnAlCuMg alloys.
[0037] The requirement for the invention is to enhance the
processability of zinc wrought alloys. This object was achieved by
alloying with titanium. There may be mentioned, in particular, the
machining properties that were significantly improved thereby, so
that a machining index within the reference range of free-machining
brass (CuZn39Pb3) can be achieved. In the experiments, it is found
that the titanium content leads to ideal chip shapes. Surprisingly,
increased cutting speeds could be achieved additionally, which
significantly enhances productivity.
[0038] The prepared products made of the titanium-containing zinc
wrought alloy according to the invention are more cost-effective
than comparably lead-free brass materials. This results from a
lower density and an excellent processability caused by the optimum
composition of zinc, aluminum, copper, magnesium and titanium.
[0039] In the following Examples, the present invention is further
explained in a non-limiting way, and advantages over the prior art
are pointed out.
EXAMPLES
[0040] The zinc wrought alloy according to the invention was
compared with the following materials:
TABLE-US-00001 TABLE 1 Comparative material (comparative
experiments) Properties Unit Zinc alloy Aluminum content % by
weight 13-25 Copper content % by weight 0.2-3.5 Magnesium content %
by weight <0.1 Lead content % by weight <0.004 Zinc content %
by weight balance Tensile strength MPa 412 Yield strength MPa 374
Brinell hardness HB (2.5/62.5) 128 Creep tendency
(A.sub.f.sup.RT.sub.100.1) % 0.05
[0041] A zinc wrought alloy as described in EP 2 675 971 was used
as a comparative material (information in column "zinc alloy" in
Table 1).
[0042] The qualification of the zinc wrought alloy according to the
invention is based on four methods delimited from one another,
which are set forth in the following. They are the basis of the
determination of the claimed composition boundaries. If one of the
compositions showed defects, this led to exclusion.
[0043] From a zinc alloy as described in Table 1 as well as from
the following alloys according to the invention, billets having a
diameter of 135 mm were prepared, which served as a starting point
for the qualification:
TABLE-US-00002 TABLE 2 Alloys according to the invention Specimen
Specimen Specimen Specimen Components Unit 1 2 3 4 Aluminum % by
weight 5-9 10-12 14-16 16-18 Copper % by weight 0.5-2.5 0.5-1.5
0.5-1.5 0.5-2.5 Magnesium % by weight 0.003-0.05 0.003-0.05
0.003-0.05 0.003-0.05 Titanium % by weight 0.05-1 0.05-1 0.05-1
0.05-1
[0044] Both the billets/alloys according to the invention and the
comparative alloys/billets were analyzed by the following methods
relating to different mechanical properties as well as
machinability (qualification):
[0045] Method 1 (Reshaping Method):
[0046] The billet was heated at 250.degree. C. in an oven.
Thereafter, the billet was extruded into a round section. Further,
the extruded round rod was drawn to a final dimension of 26 mm. The
testing requirements were considered to be met if no signs of
surface cracks or blisters have formed.
[0047] Method 2 (Tensile Test):
[0048] As the second method, a tensile test was performed. The
exact realization, the definition of the measurable characteristics
and the specimen shape are defined in DIN EN ISO 6892-1:2017.
[0049] A section of the drawn round rod having a diameter of 26 mm
was lathe-turned into a specimen for tensile testing as shown in
FIG. 1. It was clamped into the tensile testing machine and exposed
to a uniaxial load until the specimen broke. Meanwhile, the force,
width and length were continuously measured electronically, whereby
the stress-strain curve (FIG. 2) could be determined.
[0050] Method 3 (Creep Tendency):
[0051] Further, the creep tendency or creep strength according to
DIN EN ISO 204:2009 was tested as a third method. A specimen as
shown in FIG. 1 was subjected to a long-acting uniaxial tensile
force at a constant test temperature. In this case, the specimen
was loaded constantly with 100 MPa at room temperature. Meanwhile,
the axial strain was measured.
[0052] Method 4 (Shape of Chip):
[0053] In the fourth method, a section of the drawn round rod was
clamped into a turning machine. A turned part having rotational
symmetry with five recessed grooves having widths of 3 mm and
depths of 3 mm was prepared therefrom. The testing requirements
were considered to be met if the chip shape corresponds to
industrial custom.
[0054] Results:
[0055] At first, the different alloy ranges were tested with
respect to aluminum content, because the latter represents the
major alloy component. In the following Table 3, the mechanical
characteristics of the alloys according to the invention (samples 1
to 4 according to Table 2) are shown. They were determined by the
above described methods 2 and 3.
TABLE-US-00003 TABLE 3 Mechanical characteristics of the alloys
according to the invention (methods 2 and 3) Specimen Specimen
Specimen Specimen Properties Unit 1 2 3 4 Tensile MPa 397 392 411
422 strength Yield MPa 322 347 372 381 strength (R.sub.p0.2)
Brinell HB 136 128 132 133 hardness (2.5/62.5) Creep % 0.01 0.04
0.05 0.05 tendency (A.sub.f.sup.RT.sub.100.1)
[0056] Surprisingly, the selective alloying with titanium did not
have a negative impact on the mechanical characteristics. In the
comparison with the comparative material (zinc alloy from Table 1),
no significant differences could be seen.
[0057] Results of Method 4 (Shapes of Chips)--Specimens 1, 2, 3 and
4:
[0058] a) Specimens 1 to 4 According to the Invention were
Processed as Described Above Under Method 4 with the Following
Parameters:
TABLE-US-00004 TABLE 4 Machining parameters (high cutting speed)
Cutting speed [m/min] Feed speed [mm/U] 210 0.05
[0059] Photographs of the chip shapes and the specimens that were
processed are shown in FIG. 3. From the results, it can be readily
seen that all ranges of the present invention showed a good
machinability. This was shown by the spiral chips produced by each
of the four specimens. Spiral chips are advantageous, in
particular, for automated production processes. The high cutting
speed achieved increases efficiency and is thus also very
advantageous.
[0060] b) Specimens 1 to 4 According to the Invention were
Processed as Described Above Under Method 4 with the Following
Parameters:
TABLE-US-00005 TABLE 5 Machining parameters (medium cutting speed)
Cutting speed [m/min] Feed speed [mm/U] 90 0.15
[0061] Photographs of the chip shapes and the specimens that were
processed are shown in FIG. 4. At a medium cutting speed, all the
specimens showed a good machinability. Both spiral chips and
conical helical chips were produced.
[0062] Other alloys according to the invention--specimens 3a to
3d
[0063] Further, different titanium contents were tested for
determining a preferred composition by means of specimen 3:
TABLE-US-00006 TABLE 6 Specimens with different titanium contents
(alloy according to the invention): Specimen Specimen Specimen
Specimen Specimen Components Unit 3a 3 3b 3c 3d Aluminum % by
weight 14-16 14-16 14-16 14-16 14-16 Copper % by weight 0.5-1.5
0.5-1.5 0.5-1.5 0.5-1.5 0.5-1.5 Magnesium % by weight 0.003-0.05
0.003-0.05 0.003-0.05 0.003-0.05 0.003-0.05 Titanium % by weight
0.01-0.05 0.06-0.1 0.15-0.2 0.25-0.4 0.8-1.0
[0064] Results of Methods 2 and 3--Specimens 3a, 3b and 3c:
[0065] The following Table 7 shows the results of the mechanical
properties of the specimens (results of methods 2 and 3).
TABLE-US-00007 TABLE 7 Mechanical properties of the specimens with
different titanium contents (methods 2 and 3) Specimen Specimen
Specimen Specimen Properties Unit 3a 3 3b 3c Tensile MPa 401 411
409 410 strength Yield MPa 365 372 370 369 strength (R.sub.p0.2)
Brinell HB 129 132 133 131 hardness (2.5/62.5) Creep % 0.03 0.05
0.04 0.04 tendency (A.sub.f.sup.RT.sub.100.1)
[0066] Surprisingly, the titanium content in different amounts does
not show any negative impact on the mechanical properties.
[0067] Results of Method 4 (Shapes of Chips)--Specimens 3a, 3b, 3c
and 3d:
[0068] The machining parameters of Tables 4 and 5 remained
identical. Photographs of the chip shapes and the specimens that
were processed are shown in FIGS. 5 (parameters according to Table
4) and 6 (parameters according to Table 5).
[0069] In the comparison in FIG. 5, it can be readily seen that the
machining properties were improved as the titanium content
increased. The chips achieved good chip shapes, which clearly
enhances productivity in the processing in a turning machine. These
include, but are not limited to, short helical chips, spiral chips,
and long helical chips. Further, it was found that the alloy having
a Ti content of 0.1% by weight is particularly process-safe. It
constantly produced long helical chips, while the chip length
varied more with the other titanium contents.
[0070] The results from FIG. 6 are similar to those of FIG. 5 and
also show good machining properties. Short helical chips were
produced in most cases.
[0071] In the last step, the alloy 3 according to the invention was
compared with the comparative material from EP 2 657 971.
[0072] Results of Method 4 (Shapes of Chips)--Specimen 3 vs. Zinc
Alloy According to EP 2 675 971:
[0073] The machining parameters of Tables 4 and 5 remained
identical. Photographs of the chip shapes and the specimen that was
processed are shown in FIGS. 7 (parameters according to Table 4)
and 8 (parameters according to Table 5).
[0074] In the comparison in FIG. 7, the extent of improvement of
the chip shapes by the zinc alloy according to the invention can be
readily seen. At a cutting speed of 210 m/min, long entangled chips
were produced with the zinc alloy from the prior art (as mentioned
in EP 2 675 971, Comparative Example). Surprisingly, a clearly
better chip shape could be achieved by selectively alloying with
titanium. Such chip shape of the inventive alloys are ideal for
processing in a turning machine, avoiding risks and disruptions in
the cutting process, such as the chip becoming wound up around the
workpiece or the tool. A high cutting speed is also desirable, and
is also possible with the alloy according to the invention, because
the process speed of the semifinished products in the turning
machine can be increased. Surprisingly, the high cutting speed can
be achieved by the present invention.
[0075] Also at lower cutting speeds, as shown in FIG. 8, the zinc
alloy according to the invention achieved chip shapes that are
better for turning processing as compared to those obtained with
the comparative zinc alloy as described in EP 2 675 971.
* * * * *