WO2016139089A1 - Method for reprocessing a component by means of a local thermomechanical treatment - Google Patents

Abstract

The invention relates to a method for reprocessing a component (120) locally damaged during operation, said component having an originally cubic γ/γ' microstructure, wherein the local damage resulting during operation is present in a coarsened section of the γ/γ' microstructure, said coarsened section being oriented along a direction of extension. In the method, the orientation of the direction of extension of the γ/γ' microstructure which is coarsened in an oriented manner is rotated by locally heating and introducing a tensile or compressive stress (503, 505), in particular in the local damage region of the component.

Description

description

Process for reprocessing a component by means of local thermomechanical treatment

The present invention relates to a method for reprocessing (also called "Refurbishment") made available by ready for operation ^¬ dingt locally damaged components by means of the local thermomechanical treatment. The damaged components may in particular be made of single-crystal turbine blades superalloys.

In today's stationary gas turbines for power generation ever higher efficiencies are sought, resulting in ever higher hot gas temperatures and thus thermally stressed the components in the hot gas region of the gas turbine higher. This is especially true for gas turbine blades. Entspre ^¬ sponding components that bear these stresses must be equipped with an insulating coating, usually made of ceramic with an underlying primer layer, verses ^¬ hen are generally produced from single-crystal superalloys and. These are very complex and expensive components in production. Nevertheless, these construction ^¬ parts are usually only time-proof and must be checked as part of maintenance and replaced with appropriate damage. For example, damage can be from local

Structural changes due to thermal overload exist.

For economic reasons, attempts are made to keep the manufacturing and operating costs of gas turbines to a minimum. If it is possible to extend the life of expensive gas turbine components, especially those parts that were made of monocrystalline Su ^¬ perlegierungen, this means a significant economic advantage. Such a life extension can be achieved, for example, by a suitable repair method for local structural changes. Lifetime limiting for gas turbine components made of monocrystalline superalloys are mainly changes in the microstructure. Such components have a cubic γ / γ 'microstructure from the grain boundaries of the alloy components when manufactured accordingly. The microstructures are very fragmented and homogeneously distributed. Under the gleichzeiti ^¬ gen influence of heat above a certain temperature levels and mechanical stresses, this microstructure changed. It becomes more complex and depends on the direction and type of stress, which is also referred to as " ^raffolding ." These microstructural changes can be disadvantageous, in particular for the creep behavior of the ^component . Among other things, insulating coatings are used for this purpose, but in operation these coatings may be damaged or, for other reasons, they may locally exceed the temperatures required for rafting lead local rafting.

So far, the inventors of the present patent application, no repair method for damaged by local rafting components is known.

It is therefore an object of this invention to provide a method which allows the recycling of locally damaged by rafting components of monocrystalline superalloys. This object is achieved according to claim 1, the dependent claims contain advantageous Aus ^¬ designs of the invention.

According to the invention, a method for recycling a locally locally damaged component with an originally cubic γ / γ 'microstructure, wherein the operational local damage consists in a coarsening of the γ / γ' microstructure directed along an expansion direction, is provided. In this procedure, the Expansion direction of the directionally coarsened γ / γ 'microstructure by local heating and introducing a tensile and compressive stress, in particular in the region of a local damage of the component, rotated in their orientation.

The method according to the invention makes it possible to rotate the coarsened microstructures (so-called rafting or rafts) in components with an originally cubic γ / γ 'microstructure in the course of a reprocessing in a desired direction of expansion. The orientation of the rafts loading relative to the direction of the dominant local operating voltage influences the strength properties of a component, particularly at high temperatures, so that with the help of the OF INVENTION ^¬ to the invention process, the strength properties of the local damage can be selectively adjusted in the loading rich during a regeneration ,

In the context of the described method, in particular in the desired direction of expansion of the coarsened γ / γ 'microstructure, tensile stresses can be applied to the component in a pressure and / or transverse direction to the desired direction of expansion of the coarsened γ / γ' microstructure. After derzeiti ^¬ gen state of research, this leads to the desired orientation of the rafts.

The expansion direction of the rafts which is sought in the course of the recycling process can, in particular, run at right angles to the direction of expansion of the γ / γ 'microstructure, which has been coarsened due to local damage. The expansion direction of the directionally coarsened γ / γ 'microstructure from the operation is primarily dependent on whether tensile or compressive stresses predominate during operation. Compressive stresses, according to the current state of research, cause rafts parallel to the main stress direction, tensile stresses perpendicular to the principal stress direction. Depending on the mechanical and thermal load during operation and the alloy used, rafts may be advantageous in parallel or at right angles to the principal stress direction. With the method according to the invention can the appropriate extension direction of the rafts can be set for the application.

The tensile or compressive stress applied for aligning the rafts can be adjusted specifically to a specific value in the method according to the invention. This can be controlled by means of a suitable measuring device, for example by means of strain gauges. This makes it possible to ensure that sufficiently high voltages are present at the damaged area for carrying out the method without burdening the component as a whole more than necessary.

At the beginning of the process according to the invention, the direction of expansion of the coarsened γ / γ 'microstructure can be determined. This can be done with a metallurgical investigation. From this, conclusions can be drawn about the local stresses and temperatures during operation. This supports the choice of the desired expansion direction of the

Rafts.

In the context of the method according to the invention, the entire component during local heating in the area of damage and the simultaneous application of tensile or compressive stresses can be heated to at least 500 ° C. The local heating in the region of the damage then takes place at a temperature which is at least 150 ° C., preferably 200 ° C., in particular even 250 ° C. above the temperature to which the entire component is heated. Preferably, the entire component during local heating in the region of damage and the simultaneous application of tensile or compressive stresses to a temperature in the range of 650 ° C to 750 ° C, in particular 700 ° C is heated. The area of damage is then heated to a temperature between 900 ° C and 1000 ° C, in particular 950 ° C. Thus, excessive heating and thus undesirable property influencing can be avoided for the entire component. At the same time in the damaged area are sufficiently high temperatures to carry out the process before and the temperature gradient in the component moves in ^{¬ to} casual areas.

The local heating of the damaged areas, by means of a laser ^¬ SUC gene in the context of the inventive method. Thereby, the heat input can be defined locally accurately. Since the energy can also be introduced by a laser in a very short time, heat loss through heat conduction in the component is minimized and the total energy input is low compared to other methods.

During implementation of the method of the invention, the treated component by a protective gas atmosphere can be or are located in a vacuum to avoid oxidation give ^¬.

Further features, properties and advantages of the present invention will become apparent from the following description of embodiments with reference to the accompanying figures.

FIG. 1 shows by way of example a gas turbine in FIG

 a longitudinal section.

FIG. 2 shows a perspective view of a

 Blade or vane one

Turbomachine.

FIG. 3 shows a combustion chamber of a gas turbine.

FIG. 4 shows a method according to the invention

 applied to a turbine blade.

FIGS. 5 and 6 show the change of the γ / γ'-microstructure as a function of the applied voltage. FIG. 7 shows the sequence of the invention

 Procedure.

FIG. 1 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 of 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 100 104 air 135 is sucked by the compressor 105 through the intake housing and ver ^¬ seals. The 105 ^¬ be compressed air provided at the turbine end of the compressor is overall to the burners 107 leads and mixed there with a fuel. The mixture is then burned to form the working fluid 113 in the combustion chamber 110. From there, the working medium 113 flows along the hot gas channel 111 past the guide vanes 130 and the rotor blades 120. On the rotor blades 120, the working medium 113 expands in a pulse-transmitting manner, so that the rotor blades 120 drive the rotor 103 and drive 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 a material for the components, in particular for the ^turbine blade or vane 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 the rare earths or Hafnium). 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. On the MCrAlX may still be present a thermal barrier coating, and consists for example of Zr0 ₂ , Y2Ü3-Zr02, ie it is not, partially or completely stabilized by yttria and / or calcium oxide and / or magnesium oxide. Suitable coating processes, such as electron beam evaporation (EB-PVD), produce stalk-shaped grains in the thermal barrier coating.

The guide vane 130 has an inner housing 138 of the turbine 108 facing guide vane root (not Darge here provides ^¬) and a side opposite the guide-blade root vane root. The vane head faces the rotor 103 and fixed to a mounting ring 140 of the stator 143.

2 shows a perspective view of a rotor blade 120 or guide vane show ^¬ 130 of a turbomachine, which extends along a longitudinal axis of the 121st 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 following one another, a fastening region 400, a blade platform 403 adjoining thereto, and an airfoil 406 and a blade tip 415.

As a guide vane 130, the vane 130 may be pointed on its shovel 415 have a further platform (not Darge ^¬ asserted). 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, for example, as a hammerhead out staltet ^¬. 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 blade 406.

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

The blade 120, 130 can hereby be manufactured by a casting process, also by directional solidification, by a forging process, by a milling process or combinations thereof.

Workpieces with a single-crystal structure or structures are used as components for machines which are exposed during operation ho ^¬ hen mechanical, thermal and / or chemical stresses.

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 which extend over the entire length of the workpiece and here, in general language use, referred to as directionally solidified) or a monocrystalline structure, ie the entire workpiece ^¬ is of a single crystal. In these methods, you have to transition to globular (polycrystalline) solidification avoided, since non-directional growth inevitably 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 consisting of iron (Fe), cobalt (Co), Ni ^¬ ckel (Ni), X is an active element and stands for yttrium (Y) and / or silicon and / or at least one element the rare earth, 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. Besides 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-10A1-0, 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 Zr0 ₂ , Y2Ü3-Zr02, 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, e.g. Electron beam evaporation (EB-PVD) produces stalk-shaped grains in the thermal barrier coating.

Other coating methods are conceivable, for example atmospheric plasma spraying (APS), LPPS, VPS or CVD. The heat insulating layer can comprise porous, micro- or macro-cracked ^compatible 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 from 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 ^¬ As the coating of the component 120, 130, after which the component 120, the 130th The blade 120, 130 may be hollow or solid. If the blade 120, 130 is to be cooled, it is hollow and also has, if necessary, film cooling holes 418 ^(indicated by dashed lines) on.

FIG. 3 shows a combustion chamber 110 of a gas turbine.

The combustion chamber 110 is configured, for example, as so-called ^an annular ^combustion chamber, in which a plurality of in the circumferential direction about an axis of rotation 102 arranged burners 107 open into a common combustion chamber space 154 and generate flames 156th 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. To even under these unfavorable for the materials operating parameters, a relatively long service life surfaces to enable the combustion chamber wall 153 is provided on its side facing the ^working medium M facing side with a formed from heat shield elements 155. liner.

Each heat shield element 155 is made of an alloy

Working medium side with a particularly heat-resistant

Protective layer (MCrAlX layer and / or ceramic coating) equipped 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 Si ^¬ lizium and / or at least one element of rare earth, 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. On the MCrAlX, for example, a ceramic Wär ^¬ medämmschicht be present and consists for example of ZrÜ2, Y203-ZrÜ2, ie it is not, partially or fully ^¬ dig stabilized by yttrium 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.

Other coating methods are conceivable, for example atmospheric plasma spraying (APS), LPPS, VPS or CVD. The heat insulation layer may have ^¬ porous, micro- or macro-cracked ^compatible grains for better thermal shock resistance.

Reprocessing (Refurbishment) means that ^heat shield elements may need to be removed 155 after use of protective layers (for example 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. After ^¬ re-coating 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 possibly still have cooling holes (not shown) which open into the combustion chamber space 154.

An inventive method is described below with reference to Figures 4, 5, 6 and 7, for example applied to a turbine blade. FIG. 4 shows the reprocessing of a turbine blade with auxiliary means used by way of example. Figures 5 and 6 show the change of the γ / γ 'microstructure in the material of a component of relevant material depending on introduced Tensions. FIG. 7 shows a flow chart of the process according to the invention.

Although Figure 4 shows an application of the process according to the invention to a turbine blade, the application is possible to other components made of alloys having a γ / γ '-Mikro ^¬ structure.

FIGS. 5 and 6 show, by way of example, the orientation of γ / γ 'microstructures 600 in superalloys as a function of stresses 601 and 602 introduced into the material. Such superalloys initially exhibit homogeneous cubic γ / γ' microstructures when appropriately fabricated. From science is known that under simultaneous influence of mechanical tensile stresses 601 or compressive stresses 602 and heat the γ / γ 'microstructure may coarsen into a defined Ausdeh ^¬ voltage device (rafts) when temperature and / or voltage limits are exceeded. The numerical values of these limits depend on the alloy material and influence each other.

According to the current state of science, the rafts form parallel to the main stress direction when a compressive stress 602 is present and at right angles to the main stress direction when a tensile stress 601 is present. Rafts create a spatially inhomogeneous behavior of the material. The orientation of the ridges relative to the principal stress direction determines the strength and sometimes even the stiffness properties of the material and thus of the corresponding component. These influences are especially pronounced at high temperatures. Whether rafts are advantageous at right angles to the main stress direction or parallel to the main stress direction is different for the respective application, depending on the superalloy used and load case, and must be assessed for the individual case.

During the operation of components, depending on the thermal and mechanical stress, it may be local to the formation of Rafts come. The orientation depends on the local loads from operating loads. Depending on the orientation, the rafts can have negative effects on the load capacity of the component. The component is damaged in operation due to unfavorable alignment of operational rafts.

If the component no longer has the required operational stability due to the operational damage, it can not be used or repaired according to the current state of the art. An inventive re ^¬ alignment of the expansion direction of the raft can make the component in terms of operating stress again resilient and thus reusable. A global treatment of the whole component is not possible or desirable in many cases. For the example of the turbines running ^¬ shovel 120 heating of the entire component with the necessary for the realignment of rafts temperature would affect generated by work hardening properties of the blade root 183 inadmissible. With which he ^¬ inventive method it is possible the extension direction of the rafts change locally permitted without affecting the rest of the component. FIG. 4 shows an exemplary application of the method. A damaged by operational conditional rafting turbines ^¬ blade 120 provides the component by way of example used for application of the method is such a turbine ^¬ shovel 120 comprises as described above, a blade root 183, trailing edge 412, leading edge 406 and blade 406 can In operation, in particular the parts leading edge. 406 and blade 406 are damaged. Such damage results, for example, from damage to a heat-insulating layer applied to the turbine blade 120. This can inter alia by penetrated into the gas turbine

Foreign body or caused by fatigue and cracking. In areas with damaged thermal insulation layer, more heat from the working medium M of the gas turbine on the Turbine blade 120 are transmitted, which leads to local temperature increases. If such temperature increases material-dependent cross borders and are simultaneously present me ^¬ chanical stresses from the operation, there may be lo cal structural changes come as the rafting described. Such rafts may be detrimental to the load capacity of the component, depending on their direction of expansion.

To carry out the inventive method, the turbine blade is 120 angeord ^¬ net in a process chamber 506th Among other things, the process chamber 506 serves to be able to carry out the process under a protective atmosphere. The protective atmosphere can consist of a protective gas or can be realized by a technical vacuum. Among other things, the protective atmosphere serves to protect the component to which the method according to the invention is to be applied from oxidation. By suitably selecting the protective atmosphere, it is also possible to avoid or promote scattering of the laser light or to selectively influence reactions in the process zone 500. The process chamber 506 also comprises a heating device for the treated component, in the ^¬ sem example a turbine blade 120. The Heizeinrich ^¬ processing is used to heat the component to be treated integrated ^¬ Lich to a base temperature which may for example be 700 ° C , This base temperature is to choose verfahrensge ^¬ Mäss so that it has no undesirable effects on the properties of the treated component. For example, properties produced by targeted strain hardening should not be compromised. Accordingly, the choice of base temperature depends inter alia on the material of the turbine blade 120. On the other hand, the base ^¬ temperature should be chosen as high as without unwanted side effects possible in order to keep thermal stresses in the transition to processing zone 500 and the requirements for the laser 501 possible liehst low. The process zone 500 describes the batch of the turbine blade 120 that corresponds to the operational localized damage zone and in which the method of the present invention is applied To realign the rafts. The process zone 500 is heated by a laser 501 to a process temperature that allows realignment of the rafts. At ^¬ instead of a laser 501 other heat sources can be set einge- that enable localized, well-controlled heat input. The process temperature is 120 depen ^¬ gig on the used material of the turbine blade and can be for example 950 ° C. Realigning the rafts are generated as part of the application of the inventive method in addition to a process tempera ture ^¬ at the same time also mechanical stresses in sufficient level in the process zone 500th This can be achieved by clamping the turbine blade 120 505 and applying tensile and / or compressive forces 503 as well as bending and / or torsional moments 504.

By one or more suitable sensors 502 in the vicinity of the process zone, the state of stress in the process zone 500 can be monitored. The sensor 502 may be the case ^¬ play a strain gauge (DMS). By the sensor 502 is moved according to ensure that 500 mechanical stresses sufficient amount present in the process ^¬ area for the realignment of rafts and in the required direction to achieve the desired Raftausdehnungsrichtung. At the same time, the load on the turbine blade 120 can be minimized by monitoring the voltage levels ^¬ by the sensor 502, since only the necessary forces and moments 503 504 to ensure a sufficiently high voltage level in the process zone to be initiated.

When carrying out the claimed method according to the invention, the γ / γ 'microstructure of a locally damaged component due to operational conditions can be aligned in such a way that the mechanical load capacity can be advantageously improved compared to a defined load compared to the initial state. The method according to the invention brings by operation damaged blades again in operational condition and thus lowers the operating costs of gas turbines advantageous.

FIG. 7 shows the possible sequence of an application of the method according to the invention during the refurbishment of a component, for example a gas turbine blade.

A raft analysis First, the existing orientation of the rafts is determined (A), for example by metallurgical investigation. Said Koen ^¬ nen damaged, among other areas are determined. At ^¬ support points for possible damaged areas can be ^¬ game also obtained from damage to a thermal insulation lationsschicht.

B Stress analysis Operation The presence and location of the rafts allow conclusions to be drawn about the stress distribution and temperature distribution in the component during operation (B).

C Definition of target raft extension direction

In a further step C, it is to be determined which extension directions of the rafts are advantageous for the local stress during operation. From this, the mechanical stresses to be introduced into the process zone 500 are derived.

D Attach voltage sensor

In method step D, a sensor 502 for monitoring the state of stress is attached near the process zone 500 on the component to be treated. These include access to the process zone 500 and to observe the temperature resistance of the sensor.

E introduction in process chamber

In method step E, the component is mounted on a holder in the process chamber 506, connected to means for imposing forces and moments (503, 504, 505) and heated to the base temperature of, for example, 700 ° C.

F Stress introduction In process step F, forces and ^moments (503, 504, 505) are impressed onto the component in such a way that the desired stress state is established in the process zone, which is necessary for reorienting the rafts. This can be controlled by means of the sensor 502. This process step can be carried out parallel to the local heat input G, so that any changes of the tension can ^¬ voltage state are compensated from the heat input. It is ensured according to the method that during the local heat input G sufficient stresses in the process zone 500 are present.

G Local heat input "Rerafting" The processing zone 500 is heated, for example by means of a La ^¬ sers 501 to a process temperature of for example 950 ° C. As the same time impressed in the process step F voltages are present, the rafts set in an advantageously chosen direction and improve so the mechanical properties of the treated component.

The inventive method is particularly suitable for the reprocessing of locally damaged components originally cubic γ / γ 'microstructures. Such components may, in particular, be turbine blades which are impaired by local directed coarsening of the γ / γ 'microstructure in terms of their capacity to withstand operating stresses. The inventive method the off ^¬ stretching direction of the γ / γ 'microstructure can be rotated in an advantageous direction. In order to achieve this, according to the invention, the process zone 500 is locally heated, while at the same time tensile and / or compressive stresses are introduced in such a way that advantageously aligned coarsening of the microstructure is formed.

Claims

claims 1. Procedure  for recycling an operationally locally damaged component (120) with an originally cubic γ / γ '- Microstructure wherein the operational local damage consists in a long ^¬ ent facing an extension direction coarsening of the γ / γ 'microstructure,  characterized in that  the expansion direction of the directionally coarsened γ / γ 'microstructure by local heating and introduction of a tensile and / or compressive stress (503, 505),  in particular in the area of local damage to the component, is rotated in their orientation. 2. The method according to claim 1,  characterized in that  In a desired direction of expansion of the directionally coarsened γ / γ 'microstructure, a tension and / or transverse to the desired direction of expansion of the directionally coarsened γ / γ' microstructure a tensile stress is applied. 3. The method according to claim 1 or 2,  characterized in that the expansion direction of the γ / γ 'microstructure directed by the local damage is rotated in the desired direction of expansion. 4. The method according to claim 3,  characterized in that  the desired direction of expansion extends at right angles to the direction of expansion of the γ / γ 'microstructure, which has been coarsened due to the local damage. Method according to one of claims 1 to 4,  characterized in that  in the component (1020) introduced tensile and or  Compressive stresses (503, 505) can be set specifically to a specific value. 6. The method according to any one of the preceding claims,  characterized in that  the direction of expansion of the directionally coarsened γ / γ 'microstructure is determined at the beginning of the process. 7. The method according to any one of the preceding claims,  characterized in that  the entire component (120) is heated to a temperature of at least 500 ° C during the local heating and the introduction of tensile and / or compressive stresses (503, 505) in the region of local damage;  the local heating in the area of the local damage is carried out to a temperature which is at least 150 ° C above the temperature at which the entire component (120) is heated. 8. The method according to claim 7,  characterized in that  the entire component (120) is heated to a temperature in the range of 650 ° C to 750 ° C and the component is heated in the region of local damage to a temperature in the range of 900 ° C to 1000 ° C. 9. The method according to any one of the preceding claims, characterized in that  the local heating by means of a laser (501) takes place. 10. The method according to any one of the preceding claims, characterized in that  it is carried out in vacuo or under inert gas.