EP2340137A1 - Molding comprising a separate module for webs, method for the production of a casting mold, ceramic casting mold, and cast part - Google Patents

Abstract

The individual components of a molding are subject to different degrees of abrasion and have to be replaced after a certain period of time. According to the invention, the areas of the molding that are subject to a greater degree of abrasion or have greater geometrical requirements are formed separately.

Description

 Molded part with separate module for webs, method of making a mold, ceramic mold and casting

The invention relates to a molded part, which includes a separate module for the molding of webs, a method for producing a casting mold, a ceramic casting mold and a casting.

The interior of cooled turbine blades is very important for the heat distribution and heat transfers for the internal flow of the cooling medium and for some mechanical properties. So there are at the blade leading edge heat transfer bridges, which cool the flow edge, but also generate pressure losses to control the internal coolant flow. They also provide the mechanical strength of the thin vane wall portions of the flow edge. These transitions are also part of a molded part used during casting for molded parts. Due to the inflow of ceramic material, the corresponding pins are subject to a certain abrasion, which can no longer be tolerated to a certain extent. The cost of these moldings are high.

It is therefore an object of the invention to solve the above-mentioned problem.

The object is achieved by a molding according to claim 1, a method according to claim 13, a ceramic casting mold according to claim 15 and a casting according to claim 16.

In the dependent claims further advantageous measures are listed, which can be combined with each other in order to achieve further advantages. Show it

FIG. 1 component with heat transfer pins,

FIG. 2 shows a molded part according to the prior art, FIGS. 3 to 6 show molded parts with separate modules,

FIG. 7 shows a gas turbine,

FIG. 8 shows a turbine blade,

9 shows a combustion chamber with combustion chamber stones.

The figures and the description show only embodiments of the invention.

FIG. 1 shows a component 1, preferably a turbine blade 120, 130, which has a cavity 2 and walls 7, 7 '.

Between the walls 7, 7 'there are webs 4 as heat transfer bridges, which serve for mechanical stability, but also to equalize the heat distribution. These webs 4 bridge the distance between the walls 7, 7 'completely.

Such complex components 1, 120, 130 are made by casting using modular moldings 10 '(FIG. 2) to make the corresponding mold or casting core.

The mold parts 10 'represent the corresponding negative of the molds for the component 1, 120, 130.

FIG. 2 shows a module 10 'according to the prior art.

Webs 24, 24 'wear faster than the walls of the modules 13', 16 ', as they are flowed around by the ceramic material for the mold. Then the entire module 13 'and / or module 16' has to be exchanged. FIG. 3 shows a modular molded part 10 according to the invention.

The molded part 10 (FIGS. 3-6) is used in particular for the production of casting cores. The molded part 10 has a first module 13 and a second

Module 16, the inner walls enclose a cavity 11 at least partially, in the material, preferably ceramic, introduced under high pressure, preferably pressed, is. In order to produce the respective webs 4 as heat transfer pins as in FIG. 1, the second module 16 has passages 17, 17 'through which projections 25, 25' of a separate exchange module 19 pass and 25, 25 'except for the inner one Surface of the opposite first module 13 pass.

The replacement module 19 has a block 20 disposed outboard of the second module 16 (i.e., not in the cavity 11). At the block 20, the webs 25, 25 'are arranged.

When introducing material, preferably ceramic, into the cavity 11, the projections 25, 25 'prevent material from getting there.

The modules 13, 16 have no integrally connected projections (not in a cast, non-detachable, ...), which form the webs.

Too high wear of the webs 25, 25 'only the separate, smaller replacement module 19 must be replaced and not the complete first and / or second modules 13, 16.

It is obvious that in FIG. 2 the first or second module 13, 16 is chosen arbitrarily, ie the separate replacement module 19 can also be applied to the first module 13. The webs 25, 25 'can also be arranged detachably on the block 20.

Preferably, in a module 13, 16 a recess 18, 18 '(indicated by dashed lines) may be present, in which the end 26, 26' of the projection 25, 25 'come in, so that the projection 25, 25' not on the surface in Cavity 11 of the wall 13 is present.

FIG. 4 shows a further separate first module 13 or second module 16.

In this separate module, pins 22, 22 'in the first and second modules 13, 16 constitute the separate module that form protrusions in a mold part 10 and can be exchanged separately, i. the module 13, 16 is used more often, the releasably arranged pins 22, 22 '(= separate module) can be replaced after repeated use. Thus, the advantage here is that only a small portion 22, 22 'of a module 13, 16 must be replaced. Preferably, in a module 13, 16 there may be a recess (not shown, similar to Fig. 3) in which the end of the projection 25, 25 'enters, such that the projection 25, 25' is not on the surface in the cavity 11 of the wall 13 is present.

FIG. 5 shows a further exemplary embodiment of a separate exchange module 21, in which on the inside 29 of the

Module 16 (i.e., in the cavity 11), a further exchange module 21 is present, the corresponding projections 25, 25 'has.

The surface of the separate replacement module 21 then represents the boundary surface to the cavity 11 here. The module 16 represents the reinforcement for the separate replacement module 21. The separate module is made correspondingly thinner and because of low material synonymous cheaper and thus cheaper to exchange.

The first 13 or the second 16 module is divided into two parts.

The webs 25, 25 'can also be arranged detachably on the replacement module 21.

The choice of which module 13, 16, the replacement module 21 is applied irrelevant.

Preferably, in a module 13, 16 a recess 18, 18 '(indicated by dashed lines) may be present, in which the end of the projection 25, 25' in, so that the projection 25, 25 'not on the surface in the cavity 11 of the wall 13 is present.

FIG. 6 shows a further embodiment of the invention. Starting from the embodiment according to FIG. 3, both the first module 13 and the second module 16 have passages 17, 17 ', 17' ', 17' '', through which webs 25, 25 'of a further exchange module 27 and webs 25'. ', 25' "'pass through openings of a second exchange module 28 in the interior 11 and completely bridge this.

Likewise, the webs 25, 25 ', 25' ', 25' '' could also be detachably exchangeable on the replacement modules 27, 28.

FIG. 7 shows by way of example a gas turbine 100 in a longitudinal partial section.

The gas turbine 100 has inside a rotatably mounted about a rotation axis 102 rotor 103 with a shaft 101, which is also referred to as a turbine runner. Along the rotor 103 follow one another an intake housing 104, a compressor 105, for example a toroidal combustion chamber 110, in particular annular combustion chamber, with a plurality Coaxially arranged burners 107, a turbine 108 and the exhaust housing 109th

The annular combustion chamber 110 communicates with an annular annular hot gas channel 111, for example. There, for example, four turbine stages 112 connected in series form the turbine 108.

Each turbine stage 112 is formed, for example, from two blade rings. As seen in the direction of flow of a working medium 113, in the hot gas channel 111 of a row of guide vanes 115, a series 125 formed of rotor blades 120 follows.

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

Coupled to the rotor 103 is a generator or work machine (not shown).

During operation of the gas turbine 100, air 105 is sucked in and compressed by the compressor 105 through the intake housing 104. The compressed air provided at the turbine-side end of the compressor 105 is supplied to the burners 107 where it is mixed with a fuel. The mixture is then burned to form the working medium 113 in the combustion chamber 110. From there, the working medium flows

113 along the hot gas channel 111 past the guide vanes 130 and the blades 120. On the blades 120, the working medium 113 expands in a pulse-transmitting manner, so that the blades 120 drive the rotor 103 and this drives the machine coupled to it.

The components exposed to the hot working medium 113 are subject to thermal loads during operation of the gas turbine 100. The guide vanes 130 and rotor blades 120 of the first turbine stage 112, viewed in the flow direction of the working medium 113, are subjected to the greatest thermal stress in addition to the heat shield elements lining the annular combustion chamber 110. To withstand the prevailing temperatures, they can be cooled by means of a coolant. Likewise, substrates of the components can have a directional structure, ie they are monocrystalline (SX structure) or have only longitudinal grains (DS structure).

As the 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 known, for example, from EP 1 204 776 B1, EP 1 306 454, EP 1 319 729 A1, WO 99/67435 or WO 00/44949.

Likewise, blades 120, 130 may be anti-corrosion coatings (MCrAlX; M is at least one member of the group

Iron (Fe), cobalt (Co), nickel (Ni), X is an active element and stands for yttrium (Y) and / or silicon, scandium (Sc) and / or at least one element of rare earth or hafnium). Such alloys are known from EP 0 486 489 B1, EP 0 786 017 Bl, EP 0 412 397 B1 or EP 1 306 454 A1.

On the MCrAlX may still be a thermal barrier layer is present, and consists for example of Zrθ2, Y2θ3-Zrθ2, i. it is not, partially or completely stabilized by yttria and / or calcium oxide and / or magnesium oxide.

By suitable coating methods, e.g. Electron beam evaporation (EB-PVD) produces stalk-shaped grains in the thermal barrier coating.

The vane 130 has a guide vane foot (not shown here) facing the inner housing 138 of the turbine 108 and a vane head opposite the vane foot. The vane head faces the rotor 103 and fixed to a mounting ring 140 of the stator 143. FIG. 8 shows a perspective view of a moving blade 120 or guide blade 130 of a turbomachine that extends along a longitudinal axis 121.

The turbomachine may be a gas turbine of an aircraft or a power plant for power generation, a steam turbine or a compressor.

The blade 120, 130 has, along the longitudinal axis 121, a fastening area 400, an adjacent blade platform 403 and an airfoil 406 and a blade tip 415.

As a guide blade 130, the blade 130 may have another platform at its blade tip 415 (not shown).

In the mounting region 400, a blade root 183 is formed, which serves for attachment of the blades 120, 130 to a shaft or a disc (not shown). The blade root 183 is designed, for example, as a hammer head. Other designs as Christmas tree or Schwalbenschwanzfuß are possible.

The blade 120, 130 has a leading edge 409 and a trailing edge 412 for a medium flowing past the airfoil 406.

In conventional blades 120, 130, for example, solid metallic materials, in particular superalloys, are used in all regions 400, 403, 406 of the blade 120, 130.

Such superalloys are known, for example, from EP 1 204 776 B1, EP 1 306 454, EP 1 319 729 A1, WO 99/67435 or WO 00/44949. The blade 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 a monocrystalline structure or structures are used as components for machines which are exposed to high mechanical, thermal and / or chemical stresses during operation. The production of such monocrystalline workpieces, for example, by directed solidification from the melt. These are casting methods in which the liquid metallic alloy solidifies into a monocrystalline structure, ie a single-crystal workpiece, or directionally. Here, dendritic crystals are aligned along the heat flow and form either a columnar grain structure (columnar, ie grains that run the entire length of the workpiece and here, in common parlance, referred to as directionally solidified) or a monocrystalline structure, ie the whole Workpiece consists of a single crystal. In these processes, it is necessary to avoid the transition to globulitic (polycrystalline) solidification, since undirected growth necessarily forms transverse and longitudinal grain boundaries, which negate the good properties of the directionally solidified or monocrystalline component. 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 that have probably longitudinal grain boundaries but no transverse grain boundaries. These second-mentioned crystalline structures are also known as directionally solidified structures. Such methods are known from US Pat. No. 6,024,792 and EP 0 892 090 A1.

Likewise, the blades 120, 130 may have coatings against corrosion or oxidation, e.g. B. (MCrAlX; 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 EP 0 486 489 B1, EP 0 786 017 B1, EP 0 412 397 B1 or EP 1 306 454 A1.

The density is preferably 95% of the theoretical density. A protective aluminum oxide layer (TGO = thermal grown oxide layer) is formed on the MCrAlX layer (as an intermediate layer or as the outermost layer).

Preferably, the layer composition comprises Co-30Ni-28Cr-8A1-0, 6Y-0, 7Si or Co-28Ni-24Cr-10Al-0, 6Y. In addition to these cobalt-based protective coatings, nickel-based protective layers such as Ni-10Cr-12Al-0.6Y-3Re or Ni-12Co-21Cr-IIAl-O, 4Y-2Re or Ni-25Co-17Cr-10Al-0.4Y-1 are also preferably used , 5RE.

On the MCrAlX may still be present a thermal barrier coating, which is preferably the outermost layer, and consists for example of Zrθ2, Y2Ü3-Zrθ2, ie it is not, partially ^¬ or fully stabilized by yttria and / or calcium oxide and / or magnesium oxide.

The thermal barrier coating covers the entire MCrAlX layer. By suitable coating methods, e.g. Electron beam evaporation (EB-PVD) produces stalk-shaped grains in the thermal barrier coating. Other coating methods are conceivable, e.g. atmospheric plasma spraying (APS), LPPS, VPS or CVD. The thermal barrier coating may have porous, micro- or macro-cracked grains for better thermal shock resistance. The thermal barrier coating is therefore preferably more porous than the MCrAlX layer.

Refurbishment means that components 120, 130 may have to be freed of protective layers after use (eg by sandblasting). This is followed by removal of the corrosion and / or oxidation layers or products. Optionally, even cracks in the component 120, 130 are repaired. Thereafter, a the coating of the component 120, 130 and a renewed use of the component 120, 130.

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

FIG. 9 shows a combustion chamber 110 of a gas turbine.

The combustion chamber 110 is designed, for example, as a so-called annular combustion chamber, in which a multiplicity of burners 107 arranged in the circumferential direction around a rotation axis 102 open into a common combustion chamber space 154, which generate flames 156. For this purpose, the combustion chamber 110 is configured in its entirety as an annular structure, which is positioned around the axis of rotation 102 around.

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

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

These protective layers can 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.

On the MCrAlX an example, ceramic heat, may be medämmschicht, consisting for example of ZrO 2, ZrO 2 Y2Ü3-ie, it is not partially full text or ^¬ dig stabilized by yttrium oxide and / or calcium and / or magnesium oxide. Suitable coating processes, such as electron beam evaporation (EB-PVD), produce stalk-shaped grains in the thermal barrier coating.

Other coating methods are conceivable, e.g. atmospheric plasma spraying (APS), LPPS, VPS or CVD. The thermal barrier coating may have porous, micro- or macro-cracked grains for better thermal shock resistance.

Refurbishment means that heat shield elements 155 may need to be deprotected after use (e.g., by sandblasting). This is followed by removal of the corrosion and / or oxidation layers or products. If necessary, cracks in the heat shield element 155 are also repaired. This is followed by a recoating of the heat shield elements 155 and a renewed use of the heat shield elements 155.

Due to the high temperatures inside the combustion chamber 110 may also be provided for the heat shield elements 155 and for their holding elements, a cooling system. The heat shield elements 155 are then, for example, hollow and may still have cooling holes (not shown) which open into the combustion chamber space 154.

Claims

claims 1. Modular molded part (10) of a plurality of modules (13, 16) for producing a casting mold, in particular a casting core, the (10) at least comprising: a first module (13), a second module (16), the (13, 16 ) at least partially enclose a cavity (11) into which (11) material for the casting mold can be introduced, wherein in the cavity (11) webs (25, 25 ') are present, the (25, 25') the cavity (11 ) between the first module (13) and the second module (16), characterized, in that the webs (25, 25 ', 25' ', 25' '') are exchangeable and that the modules (13, 16) can be reused with renewed webs (25, 25 ', 25' ', 25' '') , 2. Molding according to claim 1, characterized in that at least one further, separate replacement module (19, 21, 27, 28, 22, 22 ') with webs (25, 25', 25 '', 25 '' ') is present. 3. Molding according to claim 2, characterized in that only another exchange module (19, 21) is present. 4. Molding according to claim 1 or 2, characterized in that at least two, in particular only two further exchange modules (27, 28) are present. 5. Molding according to claim 1, 2, 3 or 4, characterized in that the molded part (10) has a separate exchange module (19, 27, 28), the (19, 27, 28) webs (25, 25 ', 25 '', 25 '' '), wherein the first module (13) and / or the second module (16) passages (17, 17', 17 '', 17 '' ') through which the webs (25 , 25 ', 25' ', 25' "') pass through the first module (13) or through the second module (16), so that the webs (25, 25', 25 '', 25 '"') within of the cavity (11) are arranged. 6. Molding according to claim 5, wherein only one module (13, 16) passages (17, 17 '). 7. Molding according to claim 5, wherein the two modules (13, 16) passages (17, 17 ', 17' ', 17' ''). 8. Molding according to claim 1 or 2, characterized in that the first and / or second module (13, 16) has webs (25, 25 ') attached to the first (13) or second module (16) as separate and replaceable modules (22, 22'). 9. Molding according to claim 1, 2, 3 or 4, characterized in that a separate exchange module (21) rests flat on the inner side (29) of the first or second module (13, 16), wherein the module (21) has projections which form the webs (25, 25 '). 10. Molding according to claim 1, 2, 3, 5, 6, 8 or 9, wherein the opposite module (16, 13) has a recess (18, 18 ') in the wall (13, 16), in the (18, 18 ') at least partially protrude the webs (25, 25') of the exchange modules. 11. Molding according to claim 2, 3, 4, 5, 7, 9 or 10, wherein at the exchange module (19, 21, 27, 28) the webs (25, 25 ', 25' ', 25' '') are interchangeable. 12. A molding according to one or more of the preceding claims, wherein the first and second modules (13, 16) have no integrally connected projections which form webs. 13. A method for producing a casting mold, in particular a casting core, in which a molding (10) is used according to one or more of the preceding claims. 14. The method of claim 13, wherein the ceramic material is introduced into the molded part (10). 15. A ceramic casting mold, in particular a ceramic casting core, which is produced by a method according to claim 13 or 14. 16. casting (120, 130) made with a ceramic mold according to claim 15.