KR20080057225A - Method of repairing a component comprising a directed microstructure, by setting a temperature gradient during exposure to the laser heat; a component produced by such a method - Google Patents

Abstract

In a repair method according to the invention for repairing components (1) comprising a base material with a directed microstructure, the repair is performed in such a way that the repaired location (3) correspondingly has a directed microstructure like the surrounding base material. A solder (7) is applied in the region of a location (3) to be repaired and is soldered to the component (1) by means of heat exposure (9). During the heat exposure (9), a temperature gradient, i.e. for instance a temperature variation from a higher temperature to a lower temperature, is thereby produced in the region of the location (3) to be repaired.

Description

By setting a temperature gradient during exposure to laser heat, a method of repairing a part comprising a directional microstructure; and a part manufactured by the method. (METHOD OF REPAIRING A COMPONENT COMPRISING A DIRECTED MICROSTRUCTURE, BY SETTING A TEMPERATURE GRADIENT DURING EXPOSURE TO THE LASER HEAT's A COMPONENT PRODUCED BY SUCH A METHOD}

The invention relates to a part repair method comprising a base material having a directional microstructure according to claim 1 and to a part according to claim 26.

Recently, turbine components are often made of materials with directional microstructures. In this situation, materials with directional microstructures should be understood as meaning particularly single crystal materials and materials having a particle structure in which the particles extend in a common preferential direction. By way of example, particles may have a larger size in a particular preferred direction than in other directions. Parts having this type of particle structure are also known as directionally solidified parts.

Substantially high stressed components, such as turbine blades or vanes, for example, are subject to high thermal and mechanical stress during operation, which causes material fatigue and eventually cracks. Since manufacturing parts from base materials with directional microstructures is relatively expensive, it is generally intended that these types of parts be repaired after being damaged.

One method of repairing damaged parts is soldering. During this soldering, solder is applied to the material of the part at the point of damage, ie the base material, and is bonded to the base material by the heating action. However, after soldering, in the process so far conventional, the brazing material does not have a single crystal or directionally solidified structure. However, in the high temperature range, an unaligned structure occurs due to material properties that are poorer than those of the directional microstructure, and as a result, the soldering position has material properties that are poorer than those of the surrounding base material.

To repair damaged parts with directional microstructures, welding methods can also be used that can also be used to create directional microstructures in welded structures. A method of this type is disclosed, for example, in EP 089 090 A1.

Other methods and solder powders used are US Patent No. 6,283,356, US Patent 4,705,203, US Patent 4,900,394, US Patent 6,565,678, US Patent 4,830,934, US Patent 4,878,953, US Patent 5,666,643. , US Patent No. 6,454,885, US Patent 6,503,349, US Patent 5,523,170, US Patent 4,878,953, US Patent 4,987,736, US Patent 5,806,751, US Patent 5,783,318, US Patent 5,873,703 do.

US 6,050,477 discloses a method for joining two component elements, where solder is applied over most of the area between the two component elements, and a temperature gradient is used to form the same directional microstructure. . The whole part is heated.

U.S. Patent Publication No. 2003/0075587 A1 discloses a method of repairing a part having a directionally solidified microstructure, where the repaired position does not have the same microstructure as the part to be repaired.

U. S. Patent No. 6,495, 793 discloses a welding repair method for nickel-based superalloys using a laser to melt a material fed through a material conveyor. Moreover, the base material is melted during the welding process.

There is no description of the microstructure of the part or repair location.

EP 1 285 545 A1 adds an additional material that is already molten at the location to be repaired. In this case too, the base material is melted. Temperature gradients are likewise used to process components with directional microstructures.

U. S. Patent No. 4,878, 953 discloses a welding method for repairing parts having directional microstructures, wherein the material is applied in powder at the location to be repaired, which location has a particulate microstructure. Here too the base material is melted.

However, welding methods always melt the base material of the part to be repaired. After all, the melting of the base material impairs the integrity of the directional structure so that structurally bearing regions of the part should not be welded. Thus, parts with directional microstructures are repaired only by the welding process unless damage is located in the structural support area of the part. Conversely, if damage occurs to the structural support area of the part, the directional welded structure must be repaired, so that the part is determined to be unrepairable and replaced with an undamaged part.

It is therefore an object of the present invention to provide a part and a method which can be used to repair damaged parts comprising a base material having a directional microstructure even if damage occurs in the structural support area of the part.

This object is achieved by the method described in claim 1 and the parts described in claim 26 below.

In the method according to the invention for repairing a part comprising a base material having a directional microstructure, the repair is carried out in such a way that the repaired position has a directional microstructure corresponding to the directional microstructure of the surrounding base material. The base material may in particular be a nickel-based material. In the method according to the invention, the solder is applied to the area of the position to be repaired and soldered to the part by heating action. During the heating action, a temperature gradient, ie a temperature profile from high temperature to low temperature, is formed in the region of the location to be repaired.

In the soldering process, only solder, not the base material, can melt and solidify again, and the solder forms a junction with the base material, even in the structural support area of the part, without adversely affecting the good material properties of the base material. In the repair process according to the invention can be used. Epitaxial growth and solidification of the solder, ie, growth in which the crystalline orientation of the solder during solidification is determined by the substrate, ie the crystalline orientation of the base material, can be achieved by temperature gradients. Thus, temperature gradients allow for single crystal solder regions or other directional microstructures in soldered solder with similarly improved material properties compared to non-directional microstructures. Directional growth is produced in the direction of the temperature gradient, ie from the low temperature to the high temperature. Due to the directional growth and the resulting directional microstructure, the soldered solder has similarly good material properties for the base material of the part.

The temperature gradient of the repair method according to the invention is preferably created in such a way that it extends in the direction of the orientation of the directional microstructure of the base material of the part. In this way, it is possible to achieve directional growth of the solder which solidifies in the direction of the orientation of the directional microstructure of the base material.

In an advantageous variant of the method according to the invention, the solder is of a first component having a melting temperature lower than the melting temperature of the base material of the part, preferably significantly lower than the melting temperature of the first component and below the melting temperature of the base material. A second component having a melting temperature and a high strength. In an advantageous variant according to the invention, the solder is applied in the region of the position to be soldered in such a way that the proportion of the first component in the solder is higher in the region closer to the base material than in the region located further away from the base material. In this arrangement according to the invention, the first component having a low melting temperature serves to create a joint between the solder and the base material, while the component having a high melting temperature is responsible for the durability (strength) of the soldered solder. . By having a higher proportion of the first component in the base material, it is possible to form a good bond between the soldered solder and the base material. On the other hand, in the region located further away from the base material, there are more second components in relative terms, i.e. more components with higher durability, which results in the soldered position being subjected to higher stress during the next operation of the part. The areas will have higher durability.

In the method according to the invention, any heating operation that can create a temperature gradient in the area of the position to be soldered, ie the solder, can be used to provide the heating action. By way of example, it is possible to use an optical heating operation, for example with a laser or a conventional lighting device, or an induction heating operation, for example with a heating coil. Alternatively, casting furnaces for casting materials with directionally oriented microstructures can also be used.

By way of example, it is known to use a hot box for induction heating. Hot box is to be substantially understood as meaning a device having a holder holding a part to be repaired and an induction coil movably arranged in a holder for locally heating the part. The holder may overflow with an inert gas such as, for example, argon during the soldering process.

In a variant of the process according to the invention, the heat treatment of the mood material can be combined with the process of soldering the solder. In this way, refurbishment (rejuvenation) of the base material properties can be realized simultaneously with repair.

Further features, features and advantages of the present invention will become apparent from the following exemplary embodiments with reference to the attached drawings.

1A-1C show an exemplary embodiment of a method according to the invention.

2 shows a variant of an exemplary embodiment of the method according to the invention.

3 shows a turbine blade or vane.

4 shows a gas turbine.

1A is a diagram showing a schematic view of a damaged part 1.

The base material of component 1 comprises an alloy, preferably a nickel-based alloy, and has a directional microstructure, represented by a short diagonal dotted line in the figure. The damaged part of the part 1 or the position 3 to be repaired is located within the area of the surface 5 and is shown in the figure as an indentation.

In order to repair the damaged part 1, a solder 7, which is preferably in powder form in an exemplary embodiment of the invention, is applied to the precleaned damage location 3 and then heated by the action of the part 1. Solder the base material of (Fig. 1b). Preferably all of the solder 7 into the precleaned damage location 3 needs to be introduced with a small amount of solder 7 if necessary, in particular the solder 7 is not supplied to the steps during the melting operation. It is desirable.

Prior to melting, it is desirable to press the solder 7 into the damaged part or the position 3 to be repaired. This has the advantage that the entire damaged part 3 is filled with solder 7. In particular, in the case of fairly deep cracks 3 (high aspect ratios) with non-uniform cross-sectional areas, the external supply of powder using a powder feeder in accordance with the prior art means that the solder 7 is at the end of the cracks. Does not guarantee to reach. The solder 7 may be applied by paste, in the form of a slurry, or in the form of a pure powder, or a foil, which may then be introduced into the damaged part 3. Other forms of introduction or application may also be contemplated.

In this context, it is advantageous for the material composition of the solder 7 to be similar to the material composition of the component 1. By "similar" it is meant that the material of the solder 7 includes all of the components of the base material plus an additional lower melting point of one or more agents (eg boron, silicon). However, the solder 7 comprises at least one component having a melting temperature lower than the melting temperature of the base material of the part 1 so that the solder 7 is melted by the heating action but the base material of the part 1 does not melt. must do it. The solder 7 preferably consists of one component, that is, the solder 7 consists of one alloy and does not consist of a powder mixture of two alloys. Since the soldering temperature of the solder 7 during soldering is at least 30 ° C. or at least 50 ° C. lower than the melting temperature of the base material of the part 1, there is no danger to the base material. It is preferable that the difference between the soldering temperature and the melting temperature is 50 ° C to 70 ° C. This is especially important when the base material is superalloy. In the case of using superalloys, chromium is vaporized at a high temperature close to the melting temperature, so that the melting temperature of the solder 7 is as high as possible so that the difference between the soldering temperature of the solder 7 and the melting temperature of the base material is as large as possible. Should be kept as low as possible. The difference between the soldering temperature of the solder 7 and the melting temperature of the base material is also preferably at least 70 ° C, preferably 70 ° C ± 4 ° C. The maximum difference between the soldering temperature of the solder 7 and the melting temperature of the base material is preferably 120 ° C. First of all, it is preferable that the solder 7 is melted so that the solder 7 flows into the position 3 to be repaired. The temperature required to achieve this may be higher or lower than the temperature used to establish the directional microstructure.

There is no restriction on the superalloy to be soldered. However, the materials PWA 1483, PWA 1484 and RENE N5 proved to be particularly advantageous for the use of the solder 7 according to the invention. PWA 1483 has a melting point of about 1341 ° C and RENE N5 has a melting point in the range of about 1360 ° C to 1370 ° C. The melting point of the solder 7 is, for example, 1160 ° C to 1220 ° C.

With the use of high temperatures, additional problems arise, such as recrystallization in the DS or SX material, which, in turn, also results in a significant difference between the soldering temperature of the solder 7 and the melting temperature of the base material of the component 1. There is a need.

In order to perform the heating action on the solder 7, in this exemplary embodiment, an electron beam gun that irradiates the solder 7 to be melted to provide heat to the solder 7 for melting. (electron beam gun) 9 is preferably provided. The electron beam treatment is preferably carried out in a vacuum. In particular, in the case of oxidation-sensitive materials, such as in the case of superalloys, for example, oxidation plays an important role, after which the heat treatment is carried out in a vacuum by means of a laser or electron beam. The electron beam treatment has the advantage of introducing more energy into the material, and further suggests that the electron beam can be moved without contact over the position 3 to be repaired by the coil forming the optics in this embodiment. Has an advantage. The heating action on the solder 7 may also be effected by a laser beam.

The power of the laser power or electron beam is such that it completely melts the solder 7 and brings the solder 7 to the melting temperature. The soldering temperature of the solder 7 is in some cases up to 140 ° C. above the melting temperature of the solder 7. The power of the Nd-YAG laser is preferably 1500 to 2000W.

According to the invention, during the soldering operation, a temperature gradient is produced in the preferential direction of the microstructure of the base material carefully in the region of the damaged part 3. This temperature gradient can be generated by moving the component 1 and the electron beam gun 9 relative to each other. Thus, in the exemplary embodiment, the electron beam gun 9 is guided over the solder 7 in parallel with the surface 5. The rate at which the electron beam gun 9 is guided over the solder 7 is selected in such a way that a desired temperature gradient is formed in the region of the damage 3, ie in the solder 7. This temperature gradient leads to the formation of an epitaxy-type directional microstructure when the solder 7 which has been melted by the electron beam gun 9 is solidified again. The steepness of the temperature gradient can be set, for example, by the speed at which the electron beam gun 9 and the component 1 are moved relative to each other or by power. In this context, the slope of the temperature gradient is understood to mean an increase or decrease in temperature per unit length. The slope of the temperature gradient which causes the formation of the directional microstructure in the solder 7 to be solidified depends on the composition of the solder 7.

The temperature gradient to be set is provided by a so-called GV diagram, which is different for various metals and metal alloys and needs to be calculated or experimentally determined for all alloys. The curve (L) in the GV diagram is divided into two parameters, the range of solidification rate and temperature gradient, where the alloy solidifies in globulitic form, and from this globulitic form, the dendritic directionality The alloy solidifies to form a microstructure. The contents and descriptions of the GV diagrams are described, for example, in J. 1984, entitled "Columnar to equiangular transition." D. In J.D. Hunt, Vol. 65 in Materials Science and Engineering.

The temperature gradient is determined from the temperature of the component 1 on the rear side of the position 3 to be repaired and the soldering temperature of the solder 7. Preferably, as disclosed in WO 98/20995, WO 98/05450, WO 96/05006, or EP 0 631 832 A1, 1) is not cooled or kept at room temperature or, if appropriate, preheated to 300 ° C.

Methods for producing single crystal structures by laser or in an equivalent manner by electron beams are also disclosed in EP 1 437 426 A1 or WO 03/087439 A1, which produce a single crystal structure. It will form part of the present disclosure with regard to the use of lasers or electron beams to make them work.

In an exemplary embodiment of the invention, the preferred direction of the directional microstructure in the base material of the component 1 extends from left to right in the plane of the drawing. In order to induce the formation of a directional microstructure having a preferential direction corresponding to the microstructure of the base material in the solder 7 to be solidified, the electron beam gun 9 is parallel to the preferred direction of the directional microstructure of the base material. Is moved about the component 1.

If the part 1 has an SX structure, the repaired position 3 may likewise have an SX structure or alternatively a DS structure. If the part 1 has a DS structure, the repaired position 3 can likewise have a DS or alternatively an SX structure. It is preferred that the part 1 and the repaired position 3 have the same microstructure. Equally, the component 1 need not have a directionally solidified structure, in which case the directionally solidified structure of the solder 7 in the repaired position 3 has a low melting point with respect to mechanical strength at higher temperatures. Because of the compensation for the negative effect of, the directionally solidified structure in the repaired position 3 at high temperatures increases the strength of the part 1.

The width b (FIG. 1A) of the position to be repaired is 1 μm to 1000 μm, preferably approximately 500 μm. The laser or electron beam may preferably cover the entire width b of the position 3 to be repaired. Since part 1 is heated only in the region of the position to be repaired, this constitutes a local repair process or a local soldering process. It is preferable that the width b of the position 3 to be repaired is 5 µm to 300 µm. It is equally advantageous for the position 3 to be repaired to have a width b of 5 μm to 1000 μm. Moreover, the crack width b of 20 μm to 300 μm can be repaired. The position 3 to be repaired preferably has a width b of 20 μm to 100 μm. It is equally preferred that the position 3 to be repaired has a width of 50 μm to 300 μm. Further advantages are achieved if the position 3 to be repaired has a width b of between 50 μm and 200 μm. In addition, damaged or cracked portions 3 having a width of 50 µm to 100 µm are also repaired in an advantageous manner by the above process.

There is no limit to the length of the location that can be repaired. In this situation, however, the electron beam gun or the laser 9 and the electron beam can be moved in the longitudinal direction (into the plane of the drawing), in which case the laser has been described in WO 03/087439. Are moved in the same direction. The speed at which the laser beam or electron beam is moved is preferably from 100 mm / min to 130 mm / min. The holding time of the laser or electron beam depends on the material and weight of the solidification.

1c shows the part 1 after the damaged part 3 has been repaired. As shown by the dashed lines extending diagonally across the area of the currently solidified solder 7, the solidified solder 7, ie the repair material, is a directional microstructure having the same preferential orientation as the directional microstructure of the base material of the component 1; Has a structure.

The electron beam may also be wide, for example to irradiate all of the solder 7 and at least thereby fully heat the solder 7. It is not necessary for the electron beam gun to be moved. Dissipation of heat from the solder 7 into the substrate of the component 1 creates a temperature gradient inside the solder 7. The temperature is highest at the outer surface of the solder 7 and lower at the boundary between the substrate of the component 1 and the solder 7. If appropriate, the component 1 is cooled at the rear side, opposite the damage 3 or elsewhere in order to set the desired specific temperature gradient as a function of the shape of the component 1 or the shape of the damage 3. Or heated.

In an exemplary embodiment of the invention, the electron beam gun 9 is used to provide heat. Alternatively, however, other optical heating methods may be used, such as, for example, illumination by conventional lighting devices. Moreover, an induction heating method may also be used instead of the optical heating method, in which case the solder is heated by the heating coil. Finally, special heating furnaces such as, for example, "hot boxes" or casting furnaces for producing molds with directionally directed microstructures can also be used. In this case, the process used should be suitable to create a temperature gradient in the direction required for solidification in the area of damage or solder-filled damage. If a furnace is used, this can be done, for example, by a stationary furnace, which makes it possible to individually set the heating action in several areas of the furnace.

2 illustrates a modification of an exemplary embodiment of the invention that has been described with reference to FIGS. 1A-1C. In a variation of this exemplary embodiment, the solder 17 applied to the damaged part 3 comprises two components, the first of which is significantly above the melting temperature of the base material of the component 1. With low melting temperature. In contrast, the second component has a melting temperature in the range between the melting temperature of the first component and the melting temperature of the base material. In addition, the second component also particularly has a high strength, for example of approximately the size of the base material.

It is preferable that the solder 17 in the form of powder be applied to the precleaned damage 3 in such a way that the solder composition 18, in which the first component forms a relatively high proportion of powder, is applied first of all. Thereafter, application of the solder composition 19 in which the first component is present at a reduced rate than the second component is performed. If the solder 17 is soldered to the base material at this time, a high proportion of the first component, i.e. a component with a low melting temperature, facilitates soldering the solder to the base material while reducing the proportion of the first component. (19) ensures a higher strength of the repaired position.

The solder composition 18 may ensure a higher strength of the location 3 to be repaired, and the solder composition 19 may be closer to the surface to have higher oxidation and / or corrosion resistance. As an alternative to the structure of these two layers of solder 7, the solder 7 at the position 3 to be repaired has a surface of the component whose composition of the solder 7 continuously changes from the base of the position 3. Up to (5) can have a material gradient.

In all exemplary embodiments of the process according to the invention, it is used to simultaneously perform heat treatment on the base material, by heating action, to allow refurbishment (rejuvenation) of the physical properties of the base material. Solders 7 and 17 can be soldered to the base material of component 1.

In the above exemplary embodiment and variations thereof, the solders 7 and 17 are applied in powder form at the location to be repaired. However, alternatively, the solders 7 and 17 may be applied as foils or pastes.

The powders of the solders 7, 17 are, for example, in the form of nanopowders, and the particle size of the powder is less than 500 nanometers, or less than 300 nanometers or less than 100 nanometers. This is because the solder 7 of the nanopowder has a lower melting temperature compared to a conventional powder of the same composition with micrometer-sized particles. The powders of the solders 7, 17 may also comprise a mixture of nano powders and conventional powders, ie powders having a particle size in the micrometer range.

The reduction in the melting point can be set in the targeted way as a result. Foils or pastes that allow the solder 7 to be applied partially or fully may also include nanopowders.

In this case, an advantage over the prior art is that the powder is not supplied through the powder feeder but is supplied in a ready-compacted form at the location 3 to be repaired. As is known in the art, it is almost impossible to supply the nanopowder through the nozzle to the position 3 to be repaired, because the particles of the nanopowder are so small that they scatter too widely during spraying. .

3 shows a perspective view of a rotor blade 120 or guide vane 130 of the turbomachine 100, extending along the longitudinal axis 121 and repaired by the process of the present invention. .

This turbomachine may be a gas turbine of an aircraft or of a power plant generating electricity, a steam turbine or a compressor.

The blades or vanes 120, 130 continue along the longitudinal axis 121 and include a fixed area 400, adjacent blades or vane platforms 403, and a main blade or vane member 406. Like the guide vanes 130, the vanes 130 may have additional platforms (not shown) at the vane tip 415.

Blades or vane roots 183, which are used to secure the rotor blades 120, 130 to a shaft or disk (not shown), are formed in the fixed region 400.

The blade or vane root 183 is configured in the form of a hammerhead, for example. Other configurations are also possible, such as fir-trees or dovetails.

Blades or vanes 120, 130 have leading edges 409 and trailing edges 412 for media flowing past the main blade or vane part 406. do.

In the case of conventional blades or vanes 120, 130, by way of example a solid metal material, in particular superalloy, is used in all areas 400, 403, 406 of the blades or vanes 120, 130.

Superalloys of this type are described, for example, in European Patent No. 1 204 776 B1, European Patent Publication No. 1 306 454, European Patent Publication No. 1 319 729A1, International Patent Application Publication No. WO 99/67435 or International Patent Application Publication. Known in WO 00/44949, these documents form part of the present disclosure with respect to the chemical composition of the alloy.

In this case, the blades or vanes 120 and 130 are manufactured by a casting process by directional solidification.

Workpieces having a single crystal structure or structures are used as parts for machines that are exposed to high mechanical, thermal and / or chemical stresses during operation. Monocrystalline workpieces of this type are produced, for example, by directional solidification from the melt. This involves a casting process in which the liquid metal alloy is solidified (solidified) or directionally solidified to form a single crystal structure, ie a single crystal workpiece. In this case, the dendritic crystals are oriented along the direction of the heat flow and are referred to as columnar crystal grain structures (i.e., extending over the entire length of the workpiece, where they are directionally solidified, depending on the commonly used language). ) Or a single crystal structure, ie, the entire workpiece consists of one single crystal. In these processes, transition to spherical (polycrystalline) solidification needs to be prevented, because non-directional growth inevitably forms transverse and longitudinal grain boundaries, which are directionally solidified or monocrystalline. It negates the beneficial physical properties of the part.

The specification generally uses the term directionally solidified (solidified) microstructure, which has a single crystal that does not have any particle boundaries or at most small-angle boundaries, and which has longitudinally extending particle boundaries but which It should be understood to mean all of the columnar crystal structures that also have no transverse grain boundaries. This second type of crystalline structure is also described as directionally solidified microstructures (directionally solidified structures).

Processes of this type are disclosed in US Pat. No. 6,024,792 and EP 0 892 090 A1, which documents form part of this disclosure.

The blades or vanes 120 and 130 are, for example, MCrAlX (where M is one or more elements selected from the group consisting of iron (Fe), cobalt (Co), nickel (Ni), X is an active element) Yttrium (Y) and / or silicon and / or one or more rare earth elements, or hafnium (Hf), may likewise be provided with a protective layer 8 according to the invention for preventing corrosion or oxidation. Alloys of this type are disclosed in European Patent No. 0 486 489 B1, European Patent No. 0 786 017 B1, European Patent No. 0 412 397 B1 or European Patent Application Publication No. 1 306 454 A1. Regarding the composition, it forms part of the present disclosure.

A thermal barrier coating composed of, for example, ZrO ₂ , Y ₂ O ₄ _ZrO ₃ , i.e., unstabilized, partially stabilized or fully stabilized by yttrium oxide and / or calcium oxide and / or magnesium oxide, is formed on the MCrAlX phase. It is also possible to exist in.

For example, columnar particles are produced in the thermal barrier coating by a suitable coating process such as electron beam physical vapor deposition (EB-PVD).

Refurbishment means that these protective layers may have to be removed from the parts 120, 130 (eg, by sand-blasting) after the protective layers are used. At this time, the corrosion and / or oxide layers and products are removed. If appropriate, cracks in parts 120 and 130 are also repaired. Thereafter, recoating of parts 120 and 130 is performed, and then parts 120 and 130 can be reused.

The blades or vanes 120 and 130 have the form of hollow or solid. If the blades or vanes 120 and 130 are cooled, they may be hollow and also have a film-cooling hole 418.

4 shows a combustion chamber 110 of a gas turbine 100. The combustion chamber 110 is configured as known, for example, as an annular combustion chamber, in which a plurality of burners 107 generating a flame 156 arranged circumferentially around the rotational axis 102 have a common combustion chamber space. Open to 154. To this end, the combustion chamber 110 has an annular configuration which is positioned around the axis of rotation 102 throughout.

In order to achieve a relatively high efficiency, the combustion chamber 110 is designed for a relatively high temperature working medium M of approximately 1000 ° C to 1600 ° C. In order to allow a relatively long service life, even with these operating parameters that are not advantageous for the materials, a combustion chamber wall 153 is provided, facing the working medium M on one side of the combustion chamber wall 153. In this combustion chamber wall 153 an inner lining is formed from the heat shield element 155.

On the working medium side, each heat shield element 155 made of alloy is provided with a particularly heat resistant protective layer (MCrAlX layer and / or ceramic coating), or a material (solid) which the heat shield element 155 can withstand high temperatures Ceramic lumps).

These protective layers are turbine blades or vanes, namely MCrAlX, where M is at least one element selected from the group consisting of iron (Fe), cobalt (Co), nickel (Ni), X is the active element and yttrium (Y) and / Or silicon and / or one or more rare earths or hafnium (Hf). Alloys of this type are disclosed in European Patent No. 0 486 489 B1, European Patent No. 0 786 017 B1, European Patent No. 0 412 397 B1 or European Patent Application Publication No. 1 306 454 A1. Regarding the composition, it forms part of the present disclosure.

For example, such as _{ZrO 2, Y 2 O 4 -ZrO} 2 that is composed of yttrium oxide and / or calcium oxide and / or that are not stabilized by the magnesium oxide, partially stabilized or fully stabilized ceramic thermal barrier coating (thermal barrier It is also preferred that the coating is present on MCrAlX. Cylindrical particles are produced in the thermal barrier coating by a suitable coating process such as, for example, electron beam physical vapor deposition (EB-PVD).

Refurbishment means that after the protective layers have been used, these protective layers should be able to be removed from the heat shield element 155 (eg, by sand-blasting). At this time, the corrosion and / or oxide layers and products are removed. If appropriate, cracks in the heat shield element 155 are also repaired. Thereafter, after the recoating of the heat shield element 155 is performed, the heat shield element 155 may be reused.

Moreover, due to the high temperature inside the combustion chamber 110, a cooling system for the heat shield element 155 and / or its retaining element can be provided. At this time, the heat shield element 155 may be, for example, hollow and have a membrane-cooling hole (not shown) that opens into the combustion chamber space 154. 5 shows a partial longitudinal sectional view through the gas turbine 100 as an example. Inside, the gas turbine 100 has a rotor 103 mounted to rotate about an axis of rotation 102 and having a shaft 101 also called a turbine rotor.

Toroidal combustion chamber 110, in particular annular combustion chamber, turbine 108, and exhaust gas, having a suction housing 104, a compressor 105, for example a plurality of burners 107 arranged in a common axis. The housings 109 run along each other along the rotor 103.

The annular combustion chamber 110 is in communication with, for example, the annular hot-gas passage 111, where, for example, four consecutive turbine stages 112 form the turbine 108. For example from two blades or vane rings. When the working medium 113 is viewed in the flow direction, a row of guide vanes 115 is formed in the hot-gas passage 111, followed by a row 125 formed of the rotor blades 120.

The guide vanes 130 are fixed to the inner housing 138 of the stator 143, while the rows 125 of the rotor blades 120 are fitted to the rotor 103 by, for example, a turbine disk 133. Fit. A generator (not shown) is coupled to the rotor 103.

While the gas turbine 100 is operating, the compressor 105 sucks air 135 through the suction housing 104 and compresses it. Compressed air provided at the turbine side end of the compressor 105 is supplied to a burner 107 where it is mixed with fuel. Thereafter, the mixture is combusted in the combustion chamber 110, forming the working medium 113. From there, the working medium 113 flows along the hot-gas passage 111 past the guide vanes 130 and the rotor blades 120. The working medium 113 expands on the rotor blades 120 and transmits their expansion momentum so that the rotor blades 120 drive the rotor 103 and then the rotor 1093 couples to this rotor. The generated generator.

While the gas turbine 100 is operating, components exposed to the high temperature working medium 113 are subjected to thermal stress. Viewed in the flow direction of the working medium 113, the rotor blades 120 and the guide vanes 130 of the first turbine stage 112 together with a heat shield element lining inside the annular combustion chamber 110. The highest thermal stress is encountered. In order to be able to withstand the prevailing temperatures there, they must be cooled by a coolant.

The substrate of the part can likewise have a directional structure, ie the substrate of the part has a single crystal form (SX structure) or only has longitudinally oriented particles (DS structure). As an example, iron-based, nickel-based or cobalt-based superalloys are used as materials for the components, in particular for the components of the turbine blades or vanes 120 and 130 and for the components of the combustion chamber 110. Superalloys of this type are described in European Patent No. 1 204 776 B1, European Patent No. 1 306 454 B1, European Patent Application Publication No. 1 319 729 A1, International Patent Application Publication No. WO 99/67435, or International Patent Application Publication. WO 00/44949, which forms part of the present disclosure with respect to the chemical composition of the alloy.

Blades or vanes 120 and 130 are also corrosion resistant coatings (MCrAlX; M is one or more elements selected from the group consisting of iron (Fe), cobalt (Co), nickel (Ni), X is an active element) Yttrium (Y) and / or silicon and / or at least one rare earth unaso or hafnium). Alloys of this type are disclosed in European Patent 0 486 489 B1, European Patent 0 786 017 B1, European Patent 0 412 397 B1 or European Patent Application Publication No. 1 306 454 A1. Regarding the composition, it forms part of the present disclosure.

For example, such as _{ZrO 2, Y 2 O 4 -ZrO} 2 that is composed of yttrium oxide and / or calcium oxide and / or that are not stabilized by the magnesium oxide, partially stabilized or fully stabilized ceramic thermal barrier coating (thermal barrier coating) may also be present on the MCrAlX. Cylindrical particles are produced in the thermal barrier coating by a suitable coating process such as, for example, electron beam physical vapor deposition (EB-PVD).

The guide vane 130 has a guide vane root (not shown here) facing the inner housing 108 of the turbine 108, and a guide vane head located at an opposite end from the guide vane root. The guide vane head faces the rotor 103 and is fixed to the fixing ring 140 of the stator 143.

Claims (28)

Method for repairing a part (1) comprising a base material having a directional microstructure, Solders 7 and 17 are applied in the region of the position 3 to be repaired, The solder 7, 17 comprises one or more components, The soldering temperature of the solder is at least 30 ° C. below the melting temperature of the base material, The solders 7 and 17 are soldered to the component 1 by the heating action to the soldering temperature, During the heating action, the temperature gradient in the region of the position 3 to be repaired is set in such a way as to create a directional microstructure at the position 3 to be repaired, The location 3 to be repaired has the same directional microstructure as the surrounding base material, How to repair parts. The method of claim 1, The difference between the soldering temperature of the solders 7, 17 and the melting temperature of the base material of the component 1 is 50 ° C. or more, How to repair parts. The method of claim 1, The difference between the soldering temperature of the solders 7 and 17 and the melting temperature of the base material of the component 1 is 70 ° C. or more, How to repair parts. The method of claim 1, The difference between the soldering temperature of the solders 7 and 17 and the melting temperature of the base material is 70 ° C ± 4 ° C, How to repair parts. The method according to any one of claims 1 to 4, Above all, it is characterized in that the solders 7 and 17 are completely melted after being completely applied, How to repair parts. The method according to any one of claims 1 to 5, Characterized in that the heating action is carried out in particular in a vacuum by means of an electron beam, How to repair parts. The method according to any one of claims 1 to 6, The component 1 is characterized in that it consists of nickel- or cobalt-based superalloys, in particular Rene N5, PWA 1483 or PWA 1484, How to repair parts. The method according to claim 1, 5, 6 or 7, The temperature gradient is characterized in that it is oriented in a manner extending in the direction of the orientation of the directional microstructure of the base material of the component (1), How to repair parts. The method according to one or more of claims 1 to 8, The solder 17 is a first component having a melting temperature lower than the melting temperature of the base material of the component 1, and melting of the base material higher than the melting temperature of the first component but below the melting temperature of the base material. A second component having a melting temperature up to temperature and having high durability, The solder 17 is intended to be soldered in a higher manner in the proximity 18 of the base material than in the region 19 where the proportion of the first component in the solder 17 is further away from the base material. Applied to the area of, How to repair parts. The method according to claim 1, 8 or 9, wherein The temperature gradient is generated by an optical heating action or an induction heating action, How to repair parts. The method according to claim 1, 8 or 9, wherein Characterized in that the temperature gradient is produced by a casting furnace for producing castings having directionally oriented microstructures, How to repair parts. The method of claim 1, wherein The heat treatment of the base material is characterized in that it is integrated with the process of soldering the solder (7, 17), How to repair parts. The method according to any one of claims 1 to 12, The powder of the solders 7, 17 is characterized in that it comprises nano-powder partially and especially completely, How to repair parts. The method according to claim 1 or 5, The solder 7, 17 is characterized in that it is introduced in the form of a paste, slurry or foil on or into the position 3 to be repaired, How to repair parts. The method according to claim 1, 5, 6 or 8, Said heating action is carried out locally in the region of the position 3 to be repaired, How to repair parts. The method according to any one of claims 1 to 4, Characterized in that the solder 7 comprises only one component, How to repair parts. The method according to claim 1 or 15, The position 3 to be repaired is characterized in that it has a width (b) of 1 ㎛ to 1000 ㎛, How to repair parts. The method according to claim 1 or 5, Characterized in that the laser power and the power of the electron beam are such that they at least partially melt the solder 7, 17. How to repair parts. The method according to claim 1 or 18, The movement speed or the holding time of the laser beam or the electron beam is characterized in that the solders 7 and 17 are at a level to solidify in a dendritic form in the region of the position 3 to be repaired. How to repair parts. The method according to claim 1, 5, 6, 8, 10, 18 or 19, The temperature gradient is determined by the soldering temperature of the solders 7, 17 and the temperature of the component 1, In particular, the temperature of the component 1 is characterized in that 300 ℃ or room temperature, How to repair parts. The method of claim 17, The position 3 to be repaired is characterized in that it has a width (b) of 1 ㎛ to 500 ㎛, How to repair parts. The method of claim 17, The position 3 to be repaired is characterized in that it has a width b of 400 μm to 600 μm, in particular a width b of approximately 500 μm, How to repair parts. The method of claim 17, The position 3 to be repaired is characterized in that it has a width b of 500 μm to 1000 μm, in particular a width b of approximately 750 μm, How to repair parts. The method of claim 17, The position 3 to be repaired is characterized in that it has a width (b) of 500 ㎛ to 750 ㎛, How to repair parts. The method of claim 17, The position 3 to be repaired is characterized in that it has a width (b) of 750 ㎛ to 1000 ㎛, How to repair parts. The method according to claim 1, 2, 3, 4, 5, 8 or 15, Characterized in that the heating action is carried out in particular by means of a laser beam in vacuum, How to repair parts. Parts manufactured as described in at least one of claims 1 to 26. The method of claim 27, The parts 1, 120, 130, 155 have a position 3 where they are locally repaired by the solders 7, 17, and have a directional structure, Characterized in that the position 3 to be repaired has a width b of 1 μm to 1000 μm, part.

Images