DE202008013345U1 - Metallic pin for investment casting and casting - Google Patents

Abstract

Pin (1)
for use in a casting process of metallic melts,
which (1) has at least one element of the group platinum (Pt), palladium (Pd), iridium (Ir), nickel (Ni), silver (Ag) or aluminum (Al),
but platinum (Pt) at most partially.

Description

The The invention relates to a metallic pin used in precision casting is used in a ceramic mold.

At the Investment casting, especially with turbine blades are often inner cores present, which must be poured exactly and spacers need. These are pins from pure Platinum used.

This represents an expensive solution.

It is therefore an object of the invention to show a pin, the cheaper is and can be used in a ceramic mold.

In the dependent claims are further advantageous measures listed, which can be combined with each other, to get more benefits.

It demonstrate:

1 . 2 inventive embodiments of a pin,

3 a gas turbine

4 in perspective, a turbine blade

5 in perspective a combustion chamber and

6 a list of superalloys.

The Figures and the description represent only exemplary embodiments of the invention.

Pin general

1 shows a pin 1 used in a casting process of metal melting in a ceramic casting mold.

Here are the pins 1 in particular in monocrystalline casting or in the production of columnar solidified grains for use, in particular in turbine blades 120 . 130 ( 4 ) of superalloys such as nickel base materials ( 6 ).

Uniform pin

Preferably, the pin according to the invention 1 completely metallic.

Preferably, the pin exists 1 made of only one metallic material (alloy).

This makes recycling and manufacturing easier.

The pin 1 according to the invention, an alloy of a platinum metal, in particular platinum (Pt), palladium (Pd) or iridium (Ir).

In particular, there is the pin 1 made of a platinum alloy. The platinum alloy is an alloy of platinum (Pt), preferably with iridium (Ir) or palladium (Pd) or with iridium (Ir) and palladium (Pd): (Pt, Pd, Ir), (Pt / Pd), (Pt / Ir).

Preferably Pt70 / Ir30 (in wt%) is used. Equally interesting is the alloy Pt70 / Pd30 (in wt%).

As well preferably, a nickel alloy with platinum (or platinum-nickel alloy) or with palladium, most preferably Pt90 / Ni10 (Ts = 1680 ° C) or Pd50Ni50 or Pd70Ni30.

Also Alloys of Pd / Ir, preferably Pd90 / Ir10 are interesting with a melting point of 1600 ° C.

As well For example, silver (Ag) with low levels (<10%) can be used as an alloying additive be, so preferably Pd / Ir / Ag.

As well preferably Pt / Al can be used.

The pin 1 is made in particular inexpensively from a wire material.

Of the Price for iridium (Ir) and palladium (Pd) or the others Metals is considerably cheaper (factor at least 3 to 4), so that significant cost advantages are achieved, even if still platinum is included.

Pin with sheath

In 2 is another pin according to the invention 1 shown.

The pin 1 according to 2 has a core 4 in particular, completely, from a shell 7 encased and surrounded.

The materials of Kern 4 and sheath 7 are different.

Preferably, for the core 4 and the sheath 7 Only use metallic material that can be recycled better.

The core

The core 4 preferably has a nickel base material ( 6 ), which in particular precipitation hardened.

Also, the core can 4 have a cobalt-based alloy, in particular after 6 ,

Also preferably, the core 4 an alloy of a platinum metal (Pt, Pd, Ir) (Pt / Pd, Pt / Ir, Pt / Ir / Pt, Pd / Ir) have, in particular consist thereof. Likewise, it is preferable to use Pt / Ni or Pd / Ni.

The core 4 is made in particular of a wire material.

Further preferably, the core 4 a ceramic, in particular, consists of the core 4 from a ceramic. Ceramics are cheaper and lighter than metal, but this is a bit more expensive to recycle.

The jacket

The jacket 7 around the core 4 is preferably formed from pure platinum (Pt) or one of the abovementioned alloys of a platinum metal (Pt, Pd, Ir) (Pt / Pd, Pt / Ir, Pt / Ir / Pd, Pd / Ir).

As well preferably Pt / Al can be used.

Also, because of the smaller volume fraction of platinum (Pt), the proportion of platinum (Pt) for a pin can be 1 reduce costs so that cost advantages can be achieved without having to do without the good oxidation resistance of platinum (Pt).

In particular, the sheath exists 7 made of a platinum alloy. The platinum alloy is an alloy of platinum (Pt), preferably with iridium (Ir) and / or palladium (Pd) and / or with iridium (Ir) and palladium (Pd).

Preferably Pt70 / Ir30 (in wt%) is used.

As well interesting is the alloy Pt70 / Pd30 (in wt%).

As well preferably, a nickel alloy with platinum or palladium used, most preferably Pt90 / Ni10 (Ts = 1680 ° C) or Pd50Ni50 or Pd70Ni30.

Also Alloys of Pd / Ir, (preferably Pd90 / Ir10) are interesting with a melting point of 1600 ° C.

The Sheathing can be done by electroplating, dipping or spraying, etc. with the metal, if necessary, with a subsequent heat treatment.

The 3 shows an example of a gas turbine 100 in a longitudinal section.

The gas turbine 100 has inside about a rotation axis 102 rotatably mounted rotor 103 with a wave, which is also referred to as a turbine runner.

Along the rotor 103 follow each other on a suction housing 104 , a compressor 105 , for example, a toroidal combustion chamber 110 , in particular annular combustion chamber, with a plurality of coaxially arranged burners 107 , a turbine 108 and the exhaust case 109 ,

The ring combustion chamber 110 communicates with an example annular hot gas channel 111 , There, for example, form four successive turbine stages 112 the turbine 108 ,

Every turbine stage 112 is formed for example of two blade rings. In the flow direction of a working medium 113 seen follows in the hot gas channel 111 a row of vanes 115 one out of blades 120 formed series 125 ,

The vanes 130 are doing on an inner housing 138 a stator 143 attached, whereas the blades 120 a row 125 for example by means of a turbine disk 133 on the rotor 103 are attached.

On the rotor 103 coupled is a generator or a working machine (not shown).

During operation of the gas turbine 100 is from the compressor 105 through the intake housing 104 air 135 sucked and compressed. The at the turbine end of the compressor 105 provided compressed air becomes the burners 107 guided and mixed there with a fuel. The mixture is then added to form the working medium 113 in the combustion chamber 110 burned. From there, the working medium flows 113 along the hot gas channel 111 past the vanes 130 and the blades 120 , On the blades 120 the working medium relaxes 113 impulsively transmitting, so that the blades 120 the rotor 103 drive and this the machine coupled to him.

The hot working medium 113 exposed components are subject during operation the gas turbine 100 thermal loads. The vanes 130 and blades 120 in the flow direction of the working medium 113 seen first turbine stage 112 Be next to the ring combustion chamber 110 lining heat shield elements most thermally stressed.

Around can withstand the prevailing temperatures there these are cooled by means of a coolant.

As well substrates of the components may have a directed structure have, d. H. they are monocrystalline (SX structure) or wise only longitudinal grains on (DS structure).

As material for the components, in particular for the turbine blade 120 . 130 and components of the combustion chamber 110 For example, iron, nickel or cobalt based superalloys are used.

Such superalloys are for example from EP 1 204 776 B1 . EP 1 306 454 . EP 1 319 729 A1 . WO 99/67435 or WO 00/44949 known; These documents are part of the disclosure regarding the chemical composition of the alloys.

The vane 130 has a the inner housing 138 the turbine 108 facing Leitschaufelfuß (not shown here) and the Leitschaufelfuß opposite vane head on. The vane head is the rotor 103 facing and on a mounting ring 140 of the stator 143 established.

The 4 shows in perspective view a blade 120 or vane 130 a turbomachine, moving along a longitudinal axis 121 extends.

The Turbomachine can be a gas turbine of an aircraft or a power plant for electricity generation, a Be a steam turbine or a compressor.

The shovel 120 . 130 points along the longitudinal axis 121 consecutively a mounting area 400 , an adjoining paddle platform 403 as well as an airfoil 406 and a shovel tip 415 on.

As a guide vane 130 can the shovel 130 at her blade tip 415 have another platform (not shown).

In the attachment area 400 is a shovel foot 183 formed, for fixing the blades 120 . 130 on a shaft or disc (not shown).

The blade foot 183 is designed for example as a hammer head. Other designs as Christmas tree or Schwalbenschwanzfuß are possible.

The shovel 120 . 130 indicates a medium attached to the airfoil 406 flowed past, a leading edge 409 and a trailing edge 412 on.

With conventional blades 120 . 130 be in all areas 400 . 403 . 406 the shovel 120 . 130 For example, massive metallic materials, in particular superalloys used.

Such superalloys are for example from EP 1 204 776 B1 . EP 1 306 454 . EP 1 319 729 A1 . WO 99/67435 or WO 00/44949 known; These documents are part of the disclosure regarding the chemical composition of the alloy.

The shovel 120 . 130 can be made by a casting process, also by directional solidification, by a forging process, by a milling process or combinations thereof.

workpieces with single-crystal structure or structures are called components used for machines which have high mechanical, are exposed to thermal and / or chemical stress.

The Production of such monocrystalline workpieces is done z. B. by directed solidification from the melt. It is about thereby to casting, in which the liquid metallic alloy to single crystal structure, d. H. to monocrystalline Workpiece, or directionally solidified.

there Dendritic crystals are aligned along the heat flow and form either a columnar grain structure (kolumnar, that is grains over the entire length run of the workpiece and here, the general usage referred to as directionally solidified) or a monocrystalline one Structure, d. H. the whole workpiece consists of a single one Crystal. In these procedures one must make the transition to avoid globulitic (polycrystalline) solidification, as by undirected growth necessarily transverse and longitudinal Form grain boundaries, which have the good properties of directionally solidified or destroy monocrystalline components.

The term generally refers to directionally solidified microstructures, which means both single crystals that have no grain boundaries or at most small-angle grain boundaries, and stem crystal structures, which are probably grain boundaries running in the longitudinal direction, but not transversal Have grain boundaries. These second-mentioned crystalline structures are also known as directionally solidified structures.

Such methods are known from U.S. Patent 6,024,792 and the EP 0 892 090 A1 known; these writings are part of the revelation regarding the solidification process.

Likewise, the blades can 120 . 130 Have coatings against corrosion or oxidation, for. M is at least one element of the group iron (Fe), cobalt (Co), nickel (Ni), X is an active element and stands for yttrium (Y) and / or silicon and / or at least one element of the rare ones Earth, or hafnium (Hf)). Such alloys are known from the EP 0 486 489 B1 . EP 0 786 017 B1 . EP 0 412 397 B1 or EP 1 306 454 A1 which are to be part of this disclosure with regard to the chemical composition of the alloy. The density is preferably 95% of the theoretical density.

On the MCrAlX layer (as an intermediate layer or as the outermost layer) Layer) forms a protective aluminum oxide layer (TGO = thermal grown oxide layer).

Preferably For example, the coating composition is Co-30Ni-28Cr-8Al-0.6Y-0.7Si or Co-28Ni-24Cr-10Al-0.6Y on. Besides these cobalt-based protective coatings are also preferably nickel-based protective layers used such as Ni-10Cr-12Al-0,6Y-3Re or Ni-12Co-21Cr-11Al-0.4Y-2Re or Ni-25Co-17Cr-10Al-0.4Y-1.5Re.

On the MCrAlX may still be present a thermal barrier coating, which is preferably the outermost layer, and consists for example of ZrO ₂ , Y ₂ O ₃ -ZrO ₂ , ie it is not, partially or completely stabilized by yttria and / or calcium oxide and / or magnesium oxide.

The Thermal barrier coating covers the entire MCrAlX layer. By suitable coating methods such. B. Electron Beam Evaporation (EB-PVD) become stalk-shaped grains in the thermal barrier coating generated.

Other Coating methods are conceivable, for. B. atmospheric Plasma spraying (APS), LPPS, VPS or CVD. The thermal barrier coating can porous, micro- or macro-cracked grains for have better thermal shock resistance. The thermal barrier coating is therefore preferably more porous than the MCrAlX layer.

The shovel 120 . 130 can be hollow or solid. When the shovel 120 . 130 If it is to be cooled, it is hollow and may still have film cooling holes 418 (indicated by dashed lines).

The 5 shows a combustion chamber 110 the gas turbine 100 , The combustion chamber 110 is configured for example as a so-called annular combustion chamber, in which a plurality of circumferentially about an axis of rotation 102 arranged around burners 107 in a common combustion chamber space 154 open, the flames 156 produce. This is the combustion chamber 110 in their entirety designed as an annular structure, around the axis of rotation 102 is positioned around.

To achieve a comparatively high efficiency, the combustion chamber 110 designed for a relatively high temperature of the working medium M of about 1000 ° C to 1600 ° C. In order to allow a comparatively long service life even with these, for the materials unfavorable operating parameters, is the combustion chamber wall 153 on its side facing the working medium M side with one of heat shield elements 155 provided inner lining.

Due to the high temperatures inside the combustion chamber 110 Can also be used for the heat shield elements 155 or for the holding elements may be provided a cooling system. The heat shield elements 155 are then hollow, for example, and possibly still in the combustion chamber space 154 opening cooling holes (not shown).

Each heat shield element 155 Made of an alloy working medium side is equipped with a particularly heat-resistant protective layer (MCrAlX layer and / or ceramic coating) or is made of high temperature resistant material (solid ceramic stones).

These protective layers may be similar to the turbine blades, so for example MCrAlX means: M is at least one element of the group iron (Fe), cobalt (Co), nickel (Ni), X is an active element and stands for yttrium (Y) and / or silicon and / or at least one element of the rare earths, or hafnium (Hf). Such alloys are known from the EP 0 486 489 B1 . EP 0 786 017 B1 . EP 0 412 397 B1 or EP 1 306 454 A1 which are to be part of this disclosure with regard to the chemical composition of the alloy.

On the MCrAlX, for example, a ceramic thermal barrier coating may be present and consists for example of ZrO ₂ , Y ₂ O ₃ -ZrO ₂ , ie it is not, partially or completely stabilized by yttria and / or calcium oxide and / or magnesium oxide.

By suitable coating process such as B. electron beam evaporation (EB-PVD) stalk-shaped grains are generated in the thermal barrier coating.

Other Coating methods are conceivable, for. B. atmospheric Plasma spraying (APS), LPPS, VPS or CVD. The thermal barrier coating can porous, micro- or macro-cracked grains for have better thermal shock resistance.

Refurbishment means turbine blades 120 . 130 , Heat shield elements 155 If necessary, they must be freed of protective layers after use (eg by sandblasting). This is followed by removal of the corrosion and / or oxidation layers or products. If necessary, even cracks in the turbine blade 120 . 130 or the heat shield element 155 repaired. Thereafter, a re-coating of the turbine blades takes place 120 . 130 , Heat shield elements 155 and reuse of the turbine blades 120 . 130 or the heat shield elements 155 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 1204776 B1 [0057, 0067]
• - EP 1306454 [0057, 0067]
• - EP 1319729 A1 [0057, 0067]
• WO 99/67435 [0057, 0067]
• WO 00/44949 [0057, 0067]
• - US 6024792 [0073]
• - EP 0892090 A1 [0073]
• EP 0486489 B1 [0074, 0085]
• EP 0786017 B1 [0074, 0085]
• - EP 0412397 B1 [0074, 0085]
• - EP 1306454 A1 [0074, 0085]

Claims (26)

Pin code ( 1 ) for use in a casting process of metallic melts, which 1 ) has at least one element of the group platinum (Pt), palladium (Pd), iridium (Ir), nickel (Ni), silver (Ag) or aluminum (Al), but platinum (Pt) at most in part. A pin according to claim 1, comprising an alloy. Pin according to claim 1 or 2, whose alloy is only has two metals. Pin according to claim 1 or 2, whose alloy is only has three metals. A pin according to claim 1, 2, 3 or 4, which is at least two Elements of the group platinum (Pt), palladium (Pd), iridium (Ir), nickel (Ni), silver (Ag) or aluminum (Al), in particular from it consists. The pin of claim 1, 2, 3, 4 or 5, which is a platinum metal has, in particular consists thereof. A pin as claimed in claim 6, wherein as platinum metals platinum (Pt), palladium (Pd), iridium (Ir). Pin according to claim 1, 2, 3, 4, 5, 6 or 7, in which the pin ( 1 ) consists only of metallic material. Pin according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the pin ( 1 ) consists of only a single metallic material. Pin according to claim 2, 3, 4, 5, 6, 7, 8 or 9, wherein the pin ( 1 ) has a platinum alloy, in particular consists thereof. Pin according to claim 2, 3, 4, 5, 6, 7, 8 or 9, wherein the pin ( 1 ) has a palladium alloy, in particular consists thereof. Pin according to claim 1, 2, 3, 4, 5, 6, 7, 10 or 11, wherein the pin ( 1 ) a core ( 4 ) and a sheath ( 7 ), in particular consists thereof. Pin according to claim 12, wherein the core ( 4 ) has a superalloy, in particular a nickel-base superalloy. Pin according to claim 12, wherein the core ( 4 ) has a palladium alloy, in particular consists thereof. Pin according to claim 12, wherein the core ( 4 ) has a platinum alloy, in particular consists thereof. Pin according to claim 12, wherein the core ( 4 ) comprises a cobalt alloy, in particular consists thereof. Pin according to claim 12, wherein the core ( 4 ) comprises a ceramic, in particular consists thereof. Pin according to claim 12, 13, 14, 15, 16 or 17, in which the sheath ( 7 ) around the core ( 4 ) consists of platinum (Pt). Pin according to claim 12, 13, 14, 15, 16 or 17, in which the sheath ( 7 ) around the core ( 4 ) comprises an alloy of a platinum metal (Pt, Pd, Ir), in particular consists thereof. Pin according to claim 12, 13, 14, 15, 16, 17 or 19, in which the sheath ( 7 ) around the core ( 4 ) consists of a platinum alloy. Pin according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 19 or 20 using a platinum-palladium alloy. Pin according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 19 or 20 using a platinum-iridium alloy. Pin according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 19 or 20 using a platinum-iridium-palladium alloy becomes. Pin according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 19, in which a palladium alloy, especially Palladium-iridium is used. Pin according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 19 or 20, in which a nickel alloy with platinum (Pt) or palladium (Pd) is used. Ceramic mold holding a pin ( 1 ) according to one or more of the preceding claims.