U.S. patent application number 16/080829 was filed with the patent office on 2019-02-21 for al-casting alloy.
This patent application is currently assigned to KSM CASTINGS GROUP GMBH. The applicant listed for this patent is KSM CASTINGS GROUP GMBH. Invention is credited to Klaus GREVEN, Oliver GRIMM.
Application Number | 20190055628 16/080829 |
Document ID | / |
Family ID | 58360773 |
Filed Date | 2019-02-21 |
United States Patent
Application |
20190055628 |
Kind Code |
A1 |
GRIMM; Oliver ; et
al. |
February 21, 2019 |
AL-CASTING ALLOY
Abstract
The invention relates to an Al casting alloy.
Inventors: |
GRIMM; Oliver; (Ahlten,
DE) ; GREVEN; Klaus; (Hildesheim, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KSM CASTINGS GROUP GMBH |
Hildesheim |
|
DE |
|
|
Assignee: |
KSM CASTINGS GROUP GMBH
Hildesheim
DE
|
Family ID: |
58360773 |
Appl. No.: |
16/080829 |
Filed: |
February 16, 2017 |
PCT Filed: |
February 16, 2017 |
PCT NO: |
PCT/DE2017/100117 |
371 Date: |
August 29, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22C 21/02 20130101;
B22D 21/007 20130101; C22F 1/043 20130101 |
International
Class: |
C22C 21/02 20060101
C22C021/02; B22D 21/00 20060101 B22D021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 1, 2016 |
DE |
10 2016 103 626.9 |
Claims
1. An Al casting alloy containing at least five of the following
alloy constituents: Si: 3.0% to 3.8% by weight Mg: 0.3% to 0.8% by
weight Cr: 0.05% to 0.35% by weight Fe: <0.18% by weight Mn:
<0.06% by weight Ti: <0.16% by weight Cu: 0.006-0.015% by
weight Sr: 0.010% to 0.030% by weight Zr<0.006% by weight
Zn<0.006% by weight Impurities: <0.1% by weight and is
supplemented by Al to an extent of 100% by weight in each case.
2. The Al casting alloy as claimed in claim 1, wherein Si is
present with a content of more than 3.1% by weight, preferably of
more than 3.3% by weight, more preferably of more than 3.4% by
weight.
3. The Al casting alloy as claimed in claim 1, wherein Si is
present with a content of less than 3.7% by weight, preferably of
less than 3.5% by weight.
4. The Al casting alloy as claimed in claim 1, wherein Mg is
present with a content of more than 0.40% by weight, preferably of
more than 0.50% by weight, more preferably of more than 0.55% by
weight.
5. The Al casting alloy as claimed in claim 1, wherein Mg is
present with a content of less than 0.70% by weight, preferably of
less 0.60% by weight.
6. The Al casting alloy as claimed in claim 1, wherein Cr is
present with a content of more than 0.10% by weight, preferably of
more than 0.15% by weight, more preferably of more than 0.20% by
weight, most preferably of more than 0.25% by weight.
7. The Al casting alloy as claimed in claim 1, wherein Cr is
present with a content of at most 0.30% by weight, preferably of
less than 0.30% by weight.
8. The Al casting alloy as claimed in claim 1, wherein Fe is
present with a content of more than 0.01% by weight, preferably of
more than 0.05% by weight, more preferably of more than 0.07% by
weight.
9. The Al casting alloy as claimed claim 1, wherein Fe is present
with a content of less than 0.15% by weight, preferably of less
than 0.12% by weight.
10. The Al casting alloy as claimed in claim 1, wherein Mn is
present with a content of more than 0.01% by weight, preferably of
more than 0.02% by weight.
11. The Al casting alloy as claimed in claim 1, wherein Mn is
present with a content less than 0.15% by weight, preferably of
less than 0.12% by weight, more preferably of less than 0.10% by
weight.
12. The Al casting alloy as claimed in claim 1, wherein Ti is
present with a content of more than 0.01% by weight, preferably of
more than 0.03% by weight, more preferably of more than 0.04% by
weight.
13. The Al casting alloy as claimed in claim 1, wherein Ti is
present with a content of less than 0.10% by weight, preferably of
less than 0.08% by weight, more preferably of less than 0.065% by
weight, most preferably of less than 0.055% by weight.
14. The Al casting alloy as claimed in claim 1, wherein Cu is
present with a content of more than 0.006% by weight, preferably of
more than 0.007% by weight, more preferably of more than 0.008% by
weight, most preferably at least 0.009% by weight.
15. The Al casting alloy as claimed in claim 1, wherein Cu is
present with a content of less than 0.015% by weight, preferably of
less than 0.013% by weight, more preferably of less than 0.012% by
weight, most preferably of less than 0.011% by weight.
16. The Al casting alloy as claimed in claim 1, wherein Sr is
present with a content of more than 0.015% by weight, preferably of
more than 0.020% by weight.
17. The Al casting alloy as claimed in claim 1, wherein Sr is
present with a content of less than 0.030% by weight, preferably of
less than 0.025% by weight.
18. The Al casting alloy as claimed in claim 1, wherein Zr is
present with a content of more than 0.001% by weight.
19. The Al casting alloy as claimed in claim 1, wherein Zr is
present with a content of less than 0.005% by weight, preferably of
less than 0.004% by weight, more preferably of less than 0.003% by
weight.
20. The Al casting alloy as claimed in claim 1, wherein Zn is
present with a content of more than 0.001% by weight, preferably of
more than 0.002% by weight.
21. The Al casting alloy as claimed in claim 1, wherein Zn is
present with a content of less than 0.005% by weight, preferably of
less than 0.004% by weight.
22. The Al casting alloy as claimed in claim 1, wherein impurities
are present with a content of less than 0.05% by weight, preferably
less than 0.035% by weight.
23-32. (canceled)
33. A cast component produced from an Al casting alloy as claimed
in claim 1, wherein the cast component after a heat treatment has a
yield point R.sub.P0.2 of 300 to 330 MPa, preferably of >320 to
330 MPa, and/or an elongation at break A5 of 7% to 11%, preferably
of 8.5% to 10%, more preferably of 9% to 9.5%, and/or a tensile
strength R.sub.m of 350-375 MPa, preferably of >360-375 MPa.
Description
[0001] The invention relates to an aluminum casting alloy.
[0002] DE 10 2008 055 928 A1, DE 10 2012 108 590 A, DE 10 2013 108
127 A1 and DE 10 2014 101 317 A1 disclose various low-Si Al casting
alloys.
[0003] Proceeding from this prior art, it is an object of the
present invention to provide an improved low-Si Al casting alloy
which has especially been further developed with regard to its
mechanical properties.
[0004] This is achieved in accordance with the invention by an Al
casting alloy containing at least five of the following alloy
constituents:
Si: 3.0% to 3.8% by weight Mg: 0.3% to 0.8% by weight Cr: 0.05% to
0.35% by weight Fe: <0.18% by weight Mn: <0.06% by weight Ti:
<0.16% by weight Cu: 0.006-0.015% by weight Sr: 0.010 to 0.030%
by weight Zr<0.006% by weight Zn<0.006% by weight Impurities:
<0.1% by weight and is supplemented by Al to an extent of 100%
by weight in each case.
[0005] Such an Al casting alloy is stronger, tougher and more
ductile compared to the prior art.
[0006] The inventive selection of alloy constituents in the order
of magnitude specified leads to a further significant improvement
in the mechanical properties which is already apparent in the cast
state, but especially in a cast component after a 2-stage heat
treatment, namely a solution annealing operation and a subsequent
age hardening operation, with preferable provision of quenching of
the cast component in water between these two heat treatment steps.
For chassis applications, preferably for wheel-bearing components,
very preferably for damper stilts, wheel bearings and especially
swivel bearings, but also for control arms, the result is an
overall increase in mechanical indices.
[0007] Entirely unexpectedly, especially in relation to the
mechanical index of elongation at break A5, it has been found that
the upper limit specified as critical for copper in DE 10 2013 108
127 A1 of 0.006% by weight is exceeded in a manner essential to the
invention.
[0008] For optimization of the mechanical indices, it may be
advantageous when Cu is present with a content of more than 0.006%
by weight, preferably of more than 0.007% by weight, more
preferably of more than 0.008% by weight, most preferably at least
0.009% by weight. For optimization of the mechanical indices, it
may be advantageous when Cu is present with a content of less than
0.015% by weight, preferably of less than 0.013% by weight, more
preferably of less than 0.012% by weight, most preferably of less
than 0.011% by weight.
[0009] The alloys of the invention may contain impurities resulting
from the preparation, for example Pb, Ni, etc., as is common
knowledge to the person skilled in the art.
[0010] For optimization of the mechanical indices, it may be
advantageous when Si is present with a content of more than 3.1% by
weight, preferably of more than 3.3% by weight, more preferably of
more than 3.4% by weight. For optimization of the mechanical
indices, it may be advantageous when Si is present with a content
of less than 3.7% by weight, preferably of less than 3.5% by
weight.
[0011] It may be advantageous for particular applications when Si
is present with a content of more than 3.3% to less than 3.7% by
weight. For some other applications, it may be advantageous when Si
is present with a content of more than 3.0% to less than 3.3% by
weight.
[0012] For optimization of the mechanical indices, it may be
advantageous when Mg is present with a content of more than 0.40%
by weight, preferably of more than 0.50% by weight, more preferably
of more than 0.55% by weight. For optimization of the mechanical
indices, it may be advantageous when Mg is present with a content
of less than 0.70% by weight, preferably of less 0.60% by
weight.
[0013] For optimization of the mechanical indices, it may be
advantageous when Cr is present with a content of more than 0.10%
by weight, preferably of more than 0.15% by weight, more preferably
of more than 0.20% by weight, most preferably of more than 0.25% by
weight. For optimization of the mechanical indices, it may be
advantageous when Cr is present with a content of at most 0.30% by
weight, preferably of less than 0.30% by weight.
[0014] For optimization of the mechanical indices, it may be
advantageous when Fe is present with a content of more than 0.01%
by weight, preferably of more than 0.05% by weight, more preferably
of more than 0.07% by weight. For optimization of the mechanical
indices, it may be advantageous when Fe is present with a content
of less than 0.15% by weight, preferably of less than 0.12% by
weight.
[0015] For optimization of the mechanical indices, it may be
advantageous when Mn is present with a content of more than 0.01%
by weight, preferably of more than 0.02% by weight. For
optimization of the mechanical indices, it may be advantageous when
Mn is present with a content less than 0.15% by weight, preferably
of less than 0.12% by weight, more preferably of less than 0.10% by
weight.
[0016] For optimization of the mechanical indices, it may be
advantageous when Ti is present with a content of more than 0.01%
by weight, preferably of more than 0.03% by weight, more preferably
of more than 0.04% by weight. For optimization of the mechanical
indices, it may be advantageous when Ti is present with a content
of less than 0.10% by weight, preferably of less than 0.08% by
weight, more preferably of less than 0.065% by weight, most
preferably of less than 0.055% by weight.
[0017] For optimization of the mechanical indices, it may be
advantageous when Sr is present with a content of more than 0.015%
by weight, preferably of more than 0.020% by weight. For
optimization of the mechanical indices, it may be advantageous when
Sr is present with a content of less than 0.030% by weight,
preferably of less than 0.025% by weight.
[0018] For optimization of the mechanical indices, it may be
advantageous when Zr is present with a content of more than 0.001%
by weight. For optimization of the mechanical indices, it may be
advantageous when Zr is present with a content of less than 0.005%
by weight, preferably of less than 0.004% by weight, more
preferably of less than 0.003% by weight.
[0019] For optimization of the mechanical indices, it may be
advantageous when Zn is present with a content of more than 0.001%
by weight, preferably of more than 0.002% by weight. For
optimization of the mechanical indices, it may be advantageous when
Zn is present with a content of less than 0.005% by weight,
preferably of less than 0.004% by weight.
[0020] For numerous applications, it may be advantageous when
impurities are present with a content of less than 0.05% by weight,
preferably less than 0.035% by weight.
[0021] For certain cast components, it has been found to be
advantageous when the Al casting alloy of the invention is a
low-pressure casting Al alloy.
[0022] Accordingly, the invention also relates to a method of
producing a cast component from an Al casting alloy as claimed in
any of claims 1 to 22, in which the low-pressure casting method is
employed.
[0023] For particular cast components, it has been found to be
advantageous when the Al casting alloy is a counterpressure casting
(CPC) Al alloy.
[0024] Accordingly, the invention also relates to a method of
producing a cast component from an Al casting alloy as claimed in
any of claims 1 to 22, in which the low-pressure counterpressure
casting method is employed.
[0025] Various permanent mold casting methods are suitable in
principle as manufacturing methods for cast components, especially
as chassis parts, preferably as wheel-bearing components, very
preferably as damper stilts, wheel bearings or swivel bearings, of
motor vehicles made from the cast alloy of the invention. Owing to
the very good mechanical properties in the case of highly stressed
wheel-bearing parts of motor vehicles, however, particularly
low-pressure diecasting and the counterpressure casting (CPC)
method, which is also referred to as the counterpressure diecasting
method, are suitable as manufacturing methods.
[0026] Manufacturing methods employed for cast components,
especially as chassis parts, preferably as wheel-bearing
components, very preferably as damper stilts, wheel bearings or
swivel bearings, of motor vehicles made from the cast alloy of the
invention may advantageously be squeeze-casting, gravity diecasting
or pressure diecasting, especially thixocasting, rheocasting or
low-pressure sand casting.
[0027] In order to achieve or even further develop the
abovementioned advantages, it is advantageous when the cast
components are subjected to a two-stage heat treatment, namely a
solution annealing operation and a subsequent age hardening
operation. It may be advantageous when the cast component is
quenched in water between the two heat treatment stages.
[0028] It may be appropriate when the cast component after the
casting operation is solution-annealed between 530.degree. C. and
550.degree. C. for 6 to 10 h, preferably between 540.degree. C. and
550.degree. C. for 7 to 9 h, especially for 8 to 9 h, most
preferably between more than 540.degree. C. and 550.degree. C. for
7 to 9 h, especially for 8 to 9 h.
[0029] It may be appropriate when the cast component after the
casting operation is tempered between 180.degree. C. and
210.degree. C. for 1 to 8 h, especially for 1 to 6.5 h, preferably
between 180.degree. C. and 190.degree. C. for 1 to 6.5 h,
especially for 4 to 6.5 h, more preferably between 180.degree. C.
and less than 190.degree. C. for 4 to 6.5 h, especially for 5 to
6.5 h.
[0030] The invention further provides for the use of an Al casting
alloy as claimed in any of the claims or of a cast component,
especially one that has been heat-treated, as claimed in any of the
claims for chassis parts of motor vehicles, preferably for
wheel-bearing components of motor vehicles, most preferably for
damper stilts, wheel bearings or swivel bearings of motor
vehicles.
[0031] According to the invention, the cast components have an
improved strength/strain ratio coupled with improved microstructure
properties. The casting method firstly enables a casting free of
larger defects, known as craters; secondly, the microstructure is
positively affected in such a way that the number of inner
indentations that reduce elongation at break is kept to a
minimum.
[0032] As already mentioned, the Al casting alloy of the invention
has been found to be especially suitable particularly for
components under relatively high stress, such as damper stilts,
wheel bearings or swivel bearings. A very preferred process for
production of such relatively highly stressed components is the
counterpressure diecasting (CPC) method.
[0033] Cast components of the invention that have been produced
from an Al casting alloy as claimed in any of the claims and/or by
a method as claimed in any of the claims feature, after a heat
treatment, a yield point R.sub.P0.2 of 300 to 330 MPa, preferably
of >320 to 330 MPa, and/or an elongation at break A5 of 7% to
11%, preferably of 8.5% to 10%, more preferably of 9% to 9.5%,
and/or a tensile strength R.sub.m of 350-375 MPa, preferably of
>360-375 MPa.
EXAMPLE
[0034] To ascertain the mechanical properties of an alloy of the
invention containing 3.4% by weight of Si, 0.6% by weight of Mg,
0.27% by weight of Cr, 0.09% by weight of Fe, 0.03% by weight of
Mn, 0.05% by weight of Ti, 0.009% by weight of Cu, 0.022% by weight
of Sr, 0.002% by weight of Zr, 0.003% by weight of Zn and
impurities of less than 0.1% by weight, in each case supplemented
to 100% by weight with Al, what is called a "French tensile
specimen" according to DIN 50125 is cut out of a swivel bearing
produced by means of a counterpressure diecasting (CPC) method, the
swivel bearing having received a heat treatment (solution annealing
at 540.degree. C. for 8 h, quenching in water, age hardening at
180.degree. C. for 6.5 h) beforehand. The casting of comparative
examples (AlSi3Mg0.5 and AlSi3Mg0.5Cr0.3) and subsequent heat
treatment are effected under the same conditions. The alloys to be
compared differ solely in the chromium content. The specimen is
taken at the same position in the swivel bearing. The mechanical
properties of tensile strength R.sub.m, yield point R.sub.p0.2 and
elongation at break A5 according to DIN10002 are ascertained.
TABLE-US-00001 R.sub.m [MPa] R.sub.p0.2 [MPa] A5 [%] AlSi3Mg0.5 327
263 9.3 Alloy of the invention 369 322 9.12 AlSi3Mg0.5Cr0.3 358 308
6.9
[0035] Against the background of DE 10 2013 108 127 A1 and the
upper limit for copper of 0.006% by weight which is specified as
critical for the mechanical indices, the achievement of the
abovementioned mechanical indices for the alloy of the invention
was not to be expected.
* * * * *