U.S. patent application number 11/180839 was filed with the patent office on 2006-06-01 for high-temperature-resistant component and process for producing the high-temperature-resistant component.
This patent application is currently assigned to Siemens AG and Doncasters Precision Castings-Bochum GmbH. Invention is credited to Ralf Burgel, Winfried Esser, Jorn Grossmann, Wolfgang Hermann, Hael Mughrabi, Jurgen Preuhs, Florian Pyczak, Alfred Scholz, Robert Singer, Andreas Volek.
Application Number | 20060113009 11/180839 |
Document ID | / |
Family ID | 8238632 |
Filed Date | 2006-06-01 |
United States Patent
Application |
20060113009 |
Kind Code |
A1 |
Burgel; Ralf ; et
al. |
June 1, 2006 |
High-temperature-resistant component and process for producing the
high-temperature-resistant component
Abstract
A high-temperature component made of a nickel super-alloy has
the following composition in wt %: 11-13% of Cr, 3-5% of W,
0.5-2.5% of Mo, 3-5% of Al, 3-5% of Ti, 3-7% of Ta, 1-5% of Re and
a remainder of nickel.
Inventors: |
Burgel; Ralf; (Melle,
DE) ; Esser; Winfried; (Bochum, DE) ;
Grossmann; Jorn; (Hattingen, DE) ; Hermann;
Wolfgang; (Muhlheim a. d. Ruhr, DE) ; Mughrabi;
Hael; (Buckenhof, DE) ; Preuhs; Jurgen;
(Oberhausen, DE) ; Pyczak; Florian; (Buckenhof,
DE) ; Scholz; Alfred; (Reinheim, DE) ; Singer;
Robert; (Erlangen, DE) ; Volek; Andreas;
(Erlangen, DE) |
Correspondence
Address: |
LERNER GREENBERG STEMER LLP
P O BOX 2480
HOLLYWOOD
FL
33022-2480
US
|
Assignee: |
Siemens AG and Doncasters Precision
Castings-Bochum GmbH
|
Family ID: |
8238632 |
Appl. No.: |
11/180839 |
Filed: |
July 13, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10059541 |
Jan 29, 2002 |
7005015 |
|
|
11180839 |
Jul 13, 2005 |
|
|
|
PCT/EP00/07079 |
Jul 24, 2000 |
|
|
|
10059541 |
Jan 29, 2002 |
|
|
|
Current U.S.
Class: |
148/562 ;
148/404; 420/444 |
Current CPC
Class: |
C30B 11/00 20130101;
C30B 29/52 20130101; C22C 19/056 20130101 |
Class at
Publication: |
148/562 ;
148/404; 420/444 |
International
Class: |
C22C 19/05 20060101
C22C019/05 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 29, 1999 |
EP |
99 114 278.7 |
Claims
1. A high-temperature-resistant component, comprising: a
nickel-base superalloy having a composition including the following
elements, in percent by weight: TABLE-US-00003 11-13% chromium 3-5%
tungsten 0.5-2.5% molybdenum 3-5% aluminum 3-5% titanium 3-7%
tantalum 0-12% cobalt 0-1% niobium 0-2% hafnium 0-1% zirconium
0-0.05% boron 0-0.2% carbon 1-5% rhenium, and
a remainder of Ni and impurities.
2. The component according to claim 1, wherein the rhenium has a
content of at least 2% by weight.
3. The component according to claim 1, which further comprises
ruthenium having a content of from 0.1% to 5% by weight.
4. The component according to claim 3, wherein the ruthenium has a
maximum content of 3% by weight.
5. The component according to claim 1, wherein the ruthenium in
said superalloy has a minimum content of 0.5% by weight.
6. A gas turbine blade, comprising: a nickel-base superalloy having
a composition including the following elements, in percent by
weight: TABLE-US-00004 11-13% chromium 3-5% tungsten 0.5-2.5%
molybdenum 3-5% aluminum 3-5% titanium 3-7% tantalum 0-12% cobalt
0-1% niobium 0-2% hafnium 0-1% zirconium 0-0.05% boron 0-0.2%
carbon 1-5% rhenium, and
a remainder of Ni and impurities.
7. A process for producing a component, which comprises: casting
the component according to claim 1 in a conventional casting
process.
8. A process for producing a component, which comprises: cooling
the superalloy according to claim 1 to solidify directionally or in
monocrystalline form; and carrying out the cooling step in vacuo
with a liquid cooling metal or with a liquid inorganic salt.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of copending application
Ser. No. 10/059,541, filed Jan. 29, 2002, which was a continuation
of copending International Application No. PCT/EP00/07079, filed
Jul. 24, 2000, which designated the United States. This application
also claims priority of European Application 99 114 278.7 filed
Jul. 29, 1999. The prior applications are herewith incorporated by
reference in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The invention relates to a high-temperature-resistant
component made from a nickel-base superalloy. The invention also
relates to a process for producing the component.
[0003] German Published, Non-Prosecuted Patent Application DE 23 33
775 B2 describes a process for the heat treatment of a nickel
alloy. The nickel alloy includes up to 0.3% of carbon, 11-15% of
chromium, 8-12% of cobalt, 1-2.5% of molybdenum, 3-10% of tungsten,
3.5-10% of tantalum, 3.5-4.5% of titanium, 3-4% of aluminum,
0.005-0.025% of boron, 0.05-0.4% of zirconium and a remainder of
nickel. Furthermore, the alloy additionally includes 0.01-3% of
hafnium, so that a block-like carbide formation and a finely
dispersed precipitation of an Ni.sub.3(Al,Ti) phase is achieved
through a suitable heat treatment. There is no mention of rhenium
or ruthenium being added.
[0004] U.S. Pat. No. 5,611,670 discloses a rotor blade for a gas
turbine. The rotor blade has a monocrystalline platform area and a
monocrystalline blade part. A securing area of the blade is
constructed with a directionally solidified structure. The blade is
cast from a superalloy which has the following composition, in
percent by weight: up to 0.2% of carbon, 5-14% of chromium, 4-7% of
aluminum, 2-15% of tungsten, 0.5-5% of titanium, up to 3% of
niobium, up to 6% of molybdenum, up to 12% of tantalum, up to 10.5%
of cobalt, up to 2% of hafnium, up to 4% of rhenium, up to 0.035%
of boron, up to 0.035% of zirconium and a remainder of nickel.
Those wide ranges are used to specify alloy compositions which are
suitable, in principle, for proposed gas turbine blades, but do not
indicate a composition range which is appropriate with a view to a
particular resistance to oxidation and corrosion or strength.
[0005] European Patent EP 0 297 785 B1 has disclosed a nickel-base
superalloy for single crystals. The superalloy has the following
composition, in percent by weight: 6-15% of chromium, 5-12% of
tungsten, 0.01-4% of rhenium, 3-9% of tantalum, 0.5-2% of titanium,
4-7% of aluminum and optionally 0.5-3% of molybdenum. This
superalloy results both in a resistance to high-temperature
cracking and in a resistance to corrosion. The titanium content
must not exceed 2% by weight in order not to impair the resistance
to corrosion.
[0006] U.S. Pat. No. 5,122,206 has disclosed a nickel-base
superalloy which has a particularly narrow coexistence zone for the
solid and liquid phases and is therefore particularly suitable for
a single-crystal casting process. The alloy has the following
composition, in percent by weight: 10-30% of chromium, 0.1-5% of
niobium, 0.1-8% of titanium, 0.1-8% of aluminum, 0.05-0.5% of
copper or, instead of copper, 0.1-3% of tantalum. In the former
case, hafnium or rhenium may optionally also be present, in an
amount of from 0.05-3%, while in the latter case 0.05-0.5% of
copper may also be present instead of rhenium or hafnium.
Furthermore, it is optionally possible to provide 0.05-3% of
molybdenum or tungsten.
SUMMARY OF THE INVENTION
[0007] It is accordingly an object of the invention to provide a
high-temperature-resistant component and a process for producing
the high-temperature-resistant component, which overcome the
hereinafore-mentioned disadvantages of the heretofore-known
products and processes of this general type and in which the
component is made from a nickel-base superalloy that has
particularly favorable properties with regard to its ability to
withstand high temperatures, its resistance to oxidation and
corrosion and its stability with respect to the formation of
intermetallic phases which have the effect of reducing
ductility.
[0008] With the foregoing and other objects in view there is
provided, in accordance with the invention, a
high-temperature-resistant component. The component comprises a
nickel-base superalloy having a composition including the following
elements, in percent by weight: TABLE-US-00001 11-13% chromium 3-5%
tungsten 0.5-2.5% molybdenum 3-5% aluminum 3-5% titanium 3-7%
tantalum 0-12% cobalt 0-1% niobium 0-2% hafnium 0-1% zirconium
0-0.05% boron 0-0.2% carbon 1-5% rhenium, and
a remainder of Ni and impurities.
[0009] The superalloy of the component described above has been
specified for the first time, in terms of its composition, in such
a way that the component has particularly favorable properties with
regard to its ability to withstand high temperatures, its
resistance to oxidation and corrosion and with regard to stability
with respect to the formation of intermetallic phases which have
the effect of reducing ductility. Extensive experiments made it
possible to determine the specific composition described herein,
through the use of which the desired, above-mentioned properties
are satisfied to a surprisingly high degree. In particular, the
invention is based on a chromium-rich superalloy which acquires a
high strength through the addition of rhenium. The formation of
embrittling intermetallic phases, which is promoted by rhenium, is
controlled by the subtle balance with the other elements in the
composition.
[0010] In accordance with another feature of the invention, the
rhenium content is preferably at least 2% by weight.
[0011] It is possible for the superalloy to also have a content of
ruthenium of 0.1 to 5 wt %. The addition of ruthenium in particular
enables the tendency to form embrittling intermetallic phases to be
reduced further. It has proven expedient to add ruthenium
particularly with a rhenium content of over 2% by weight. In
accordance with a further feature of the invention, in this case,
the maximum ruthenium content is preferably 3% by weight, and the
minimum ruthenium content is 0.1% by weight.
[0012] In accordance with an added feature of the invention, the
cobalt content of the superalloy is preferably up to 12% by
weight.
[0013] In accordance with an additional feature of the invention,
the superalloy preferably contains at most 1% by weight of
niobium.
[0014] In a preferred composition, the cobalt content of the
superalloy is lower than 12% by weight, while the niobium content
is at most 1% by weight. Preferably, 0-2% by weight of hafnium
and/or 0-1% by weight of zirconium and/or 0-0.05% by weight of
boron and/or 0-0.2% by weight of carbon are included in the
superalloy.
[0015] In accordance with a further feature of the invention, the
component preferably has a directionally solidified grain
structure. In a directionally solidified structure of this type,
the grain boundaries are oriented substantially along one axis.
This results in a particularly high strength along this axis.
[0016] In accordance with an added feature of the invention, the
component preferably has a monocrystalline structure. The
monocrystalline structure avoids strength-reducing grain boundaries
in the component and results in a particularly high strength.
[0017] In accordance with an additional feature of the invention,
the component is constructed as a gas turbine blade. A gas turbine
blade is a component which is exposed to particularly high demands
in terms of its ability to withstand high temperatures and its
resistance to oxidation/corrosion.
[0018] With the objects of the invention in view, there is
additionally provided a process for producing a component from a
superalloy in accordance with the above-described embodiments,
through the use of a conventional casting process. A fine-grained
precision-cast structure is achieved for the component in a
conventional casting process of this type. This casting process is
particularly inexpensive.
[0019] With the objects of the invention in view, there is also
provided a process for producing a component from a superalloy
having the above composition, in which the superalloy is cooled in
such a way that it solidifies directionally or in single crystal
form, with the cooling taking place in vacuo through the use of a
liquid cooling metal. A process of this type, which is known as
liquid metal cooling, considerably improves the quality and speed
of the casting process. Cooling takes place only by radiation,
especially in vacuo. The cooling capacity is considerably increased
by a liquid cooling metal. This allows the solidification process,
in which the component that is to be solidified is cooled along a
component axis, to be optimized for solidification which is as
flawless and rapid as possible.
[0020] Other features which are considered as characteristic for
the invention are set forth in the appended claims.
[0021] Although the invention is illustrated and described herein
as embodied in a high-temperature-resistant component and a process
for producing the high-temperature-resistant component, it is
nevertheless not intended to be limited to the details shown, since
various modifications and structural changes may be made therein
without departing from the spirit of the invention and within the
scope and range of equivalents of the claims.
[0022] The construction and method of operation of the invention,
however, together with additional objects and advantages thereof
will be best understood from the following description of specific
embodiments when read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a fragmentary, diagrammatic, elevational view of a
gas turbine blade;
[0024] FIG. 2 is a cross-sectional view of an apparatus for
carrying out a process for producing a gas turbine blade;
[0025] FIG. 3 is a table showing alloy compositions; and
[0026] FIG. 4 is another table showing alloy compositions.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Referring now to the figures of the drawings in detail and
first, particularly, to FIG. 1 thereof, there is seen a
high-temperature-resistant component, which is constructed as a gas
turbine blade 1. The gas turbine blade 1 has a blade part 3, a
platform 5 and a securing area 7. The gas turbine blade 1 is
produced in directionally solidified form in a casting process, as
a result of which grain boundaries 9 that are oriented along a
blade axis 8 are formed.
[0028] The gas turbine blade 1 is produced from a nickel-base
superalloy which has one of the compositions listed in tables shown
in FIGS. 3 and 4. The tables seen in FIGS. 3 and 4 contain the
content in percent by weight of one element in each column, for
twelve different alloys L1-L12. The remainder, making a total of up
to 100%, is nickel and inevitable impurities. A portion of cobalt
of between 6 and 10% and a content of zirconium of between 0 and
0.1% is especially advantageous.
[0029] FIG. 2 shows a melt 101 of a metal, in particular of a
superalloy, for the production of turbine blades 1 in a casting
mold 102. The casting mold 102 is to be immersed in a bath 103 of a
liquid cooling medium, preferably tin, an inorganic salt or boron
oxide, for the purpose of cooling. A liquid cooling medium 103A is
at a second temperature, which is lower than a first temperature of
the melt 101. The bath 103 is covered by a covering layer 104,
which is formed of a free-flowing, thermally insulating bulk
material including spherical solid bodies 105, 106 (hollow beads
105 and solid beads 106). The hollow beads 105 preferably are
formed of a ceramic material, such as silicon dioxide/aluminum
oxide (mullite). The solid beads 106 preferably are formed of a
material such as aluminum oxide, magnesium oxide or zirconium
oxide. The solid bodies made from a solid material may also
include, for example, particles 106 of a commercially available
powder. The covering layer 104 considerably reduces the
introduction of heat into the bath 103 from a heating zone 107, in
which the casting mold 102 containing the melt 101 is initially
held. The casting mold 102 is at a very high first temperature, in
particular 1600.degree. C., in the heating zone 107. A high
temperature drop, corresponding to a particularly high temperature
gradient, is established in the interior of the covering layer 104.
Heat is introduced into the melt 101 and the casting mold 102
following the heating zone 107 and heat is dissipated from the melt
101 and the casting mold 102 in the bath 103. Therefore, a high
temperature gradient is likewise established in the melt 101 in the
area where the casting mold 102 passes through the covering layer
104. A high temperature gradient of this nature results in
directional solidification of the melt 101 to form a workpiece or a
plurality of workpieces, in particular a turbine blade 1, with a
columnar crystal or a single crystal microstructure. The casting
mold 102 can be moved into the bath 103 through the use of a
holding frame 111.
[0030] Particularly preferred alloys have the following
composition: TABLE-US-00002 Al: 3.4; Cr: 12.5%; Co: 9%; Mo: 1.9%;
W: 4%; Ta: 4%; Ti: 3.9%; Re: 3% C: 0.08%; B: 125 ppm; Zr: 80 ppm;
Hf: <100 ppm; Ni: bal. Al: 3.6-4; Cr: 12.5%; Co: 9%; Mo: 1.9%;
W: 4%; Ta: 6%; Ti: 3.9%; C: 0.08%; B: 125 ppm; Zr: 80 ppm; Hf:
<100 ppm; Ni: bal. Al: 3.8; Cr: 12%; Co: 4%; Mo: 1.5%; W: 3.5%;
Ta: 6%; Ti: 3.9%; Re: 2.5% C: 0.08%; B: 125 ppm; Zr: 80 ppm; Hf:
<100 ppm; Ni: bal. Al: 3.8; Cr: 12%; Co: 4%; Mo: 1.5%; W: 3.5%;
Ta: 6%; Ti: 3.9%; Re: 2.5% Ru: 1%; C: 0.08%; B: 25 ppm; Zr: 80 ppm;
Hf: <100 ppm; Ni: bal. Al: 3.8; Cr: 12%; Co: 4%; Mo: 1.9%; W:
4%; Ta: 6%; Ti: 3.9%; Re: 1.5% C: 0.08%; B: 125 ppm; Zr: 80 ppm;
Hf: <100 ppm; Ni: bal.
* * * * *