DE102005015153B4 - Method for repairing or renewing cooling holes of a coated component and coated component with cooling holes of a gas turbine - Google Patents

Abstract

Method for repairing or renewing cooling holes (5) of a coated component (1) of a gas turbine, comprising the following steps: - removing at least one old coating (3, 4) from an outside (2) of the component (1) at least in one cooling hole (5) enclosing hole region (12), wherein the cooling hole (5) at least after the removal of the at least one old coating (3, 4) at least in one of the outer side (2) of the component (1) adjoining longitudinal portion (11) an alt -Cross-section (13) which is greater than a desired cross-section (6), the cooling hole (5) in an original new state of the finished component (1) in this longitudinal section (11), - attaching at least one new coating ( 3 ', 4') on the component (1) at least in the hole region (12) and at least in the longitudinal section (11) of the cooling hole (5), such that the cooling hole (5) at least in the longitudinal section (11) and / or in the hole area (12) an intermediate Que partial removal of the at least one new coating (3 ', 4') within the cooling hole (5) with a laser method, characterized in that the Cooling hole (5) at least in the longitudinal section (11) and / or in the hole region (12) has a Neu-cross section (18) which is about the same size as the desired cross-section (6) that the laser method as laser ablation Method is designed and operates with pulse frequencies in the range of 1 kHz to 100 kHz.

Description

Technical area

The present invention relates to a method for repairing or renewing cooling holes of a coated component of a gas turbine.

Components of gas turbines, such as blades, vanes, heat shield elements, or other cooled parts, often contain voids which serve to distribute cooling air to a plurality of cooling holes in a wall of the respective component. These cooling holes lead the cooling air to an outer surface exposed to the hot working gases of the gas turbine. Such components are usually provided with an oxidation and / or corrosion protection layer, which may also be referred to as a base coat. In addition, the components may also be provided with a heat protection layer which serves to thermally insulate the component. During operation of the gas turbine, degradation of the coating or coatings often occurs before the coated component itself is attacked. As a result, at least once during the lifetime of the respective component, the base coat and, if necessary, the heat protection layer must be removed and reapplied.

When applying a new coating, however, the existing cooling holes are problematic. While in the manufacture of a new component, the cooling holes are introduced after the application of the coating in the component, the cooling holes are already present when re-applying a new coating. When applying the new coating, the coating material can penetrate into the cooling holes and change their cross sections. The components of modern gas turbines can contain hundreds of such cooling holes whose cross sections or their cross-sectional profiles are within very narrow tolerance limits. The upper tolerance limit for the cooling hole cross sections should avoid the injection of unnecessary cooling air, which would drastically reduce the efficiency of the gas turbine and its power output. The lower tolerance limit for the cooling hole cross-sections should prevent overheating of the respective component, which would lead to a significant reduction in the lifetime of the respective component.

To repair or renew the cooling holes, it is basically possible to weld or solder the cooling holes after removing the old coating. Then the new coating can be applied. Then the cooling holes can be re-drilled. The problem with this is that the welding methods or soldering methods used for this purpose introduce weak points into the material of the component. Furthermore, a common drilling method is associated with positional tolerances, so that when re-drilling the cooling holes positional deviations can occur to the old cooling holes. As a result, welding material or brazing material remains in the material of the component, so that the component is put into operation with the said weak points, which impairs the mechanical strength of the component.

State of the art

From the US 5,702,288 A It is known to apply the new coating after removing the old coating without first soldering or welding the cooling holes. As a result, the new coating penetrates into the cooling holes more or less and narrows their cross-section. Subsequently, an abrasive abrasive slurry is introduced under high pressure into the cavity of the component and expelled through the cooling holes. In this way, the coating can be ground within the cooling holes. However, in this approach, internal portions of the component, such as cooling fins or inserts, as well as uncoated portions of the cooling holes are also exposed to the abrasive slurry's abrasive action. Furthermore, such a method is unsuitable for vanes incorporating a cooling air manifold insert, since such a diverter insert would have to be removed first, but this would be time and cost intensive. Furthermore, it is basically possible to press the grinding slurry from the outside through the cooling holes in the cavity of the component. Basically, however, the same difficulties occur here, and in addition, in addition, the coating of the component is exposed to the abrasive effect of the abrasive slurry.

From the US 4,743,462 A It is known to introduce volatile stoppers into the cooling holes before the application of the new coating, which at least partially evaporate during the coating process. The evaporation of the plug prevents clogging of the cooling holes by the coating material. The disadvantage here, however, that the plug must be introduced individually into the cooling holes. For large components of stationary gas turbines, which may have several hundred cooling holes, inserting the plugs individually into each cooling hole is extremely time consuming. In addition, different components may have different types of cooling holes, each requiring specially adapted plugs.

From the US 5,985,122 A , of the US 6,258,226 B1 and from the US 5,565,035 A It is known to clog using a corresponding tool simultaneously several cooling holes before attaching the new coating. However, these tools are not suitable for thermal spray coating processes.

From the US 5,800,695 A It is known to press a cover through the cavity in the cooling holes from the inside until the covering reaches the outer surface of the respective component. Subsequently, an electrolytic platinum coating can be carried out. Since the covering means is made of plastic and accordingly is not electrically conductive, the platinum can not accumulate on the covering means in the region of the cooling holes.

From the US 4,743,462 A Another method is known that works with a covering agent, which already evaporates at temperatures that are below the temperatures occurring during application of the coating. For example, it is necessary for certain oxidation and / or corrosion protection layers that they form a diffusion bond with the material of the component. In order to achieve such diffusion bonding, a high-temperature treatment is required, which proceeds, for example, in a temperature range of 1,000 ° C to 1,150 ° C. At these high temperatures, the covering agent volatilizes in any case. In order to subsequently attach a heat protection layer, the covering would have to be re-introduced.

From the US 6,004,620 A It is known to remove the penetrated into the cooling holes areas of the coating using a high pressure water jet. However, the device by means of which the high-pressure water jet can be introduced into the individual cooling holes, too unwieldy, so as to clean, for example, the cooling holes of a turbine blade from the inside. Other methods that work with a high pressure water jet are from the US 2001/001680 A1 and from the US 2001/006707 A1 known.

Furthermore, it is from the US 6,210,488 B1 It is known to remove a heat protection layer which has deposited in the interior of the cooling holes with the aid of a corrosive solution, it being possible optionally to provide an ultrasound treatment. However, such an approach is only suitable for the complete removal of the heat protection layer from the entire component. Covering the heat protection layer of the entire component apart from the individual cooling holes is impractical.

From the US 5,216,808 A It is known to remove the unwanted heat protection coating within the cooling holes by means of a pulsed ultraviolet laser. Although the wavelength of the UV laser is suitable for removing conventional heat protection layers, for example of zirconium oxide, conventional oxidation and / or corrosion protection layers can not be removed regularly or can only be removed unreliably.

Another method, which works with a cover, is from the US 6,265,022 B1 known. The covering agent used there is based on a polymer and can be used for all those coating processes in which the temperatures do not exceed a destruction of the covering causing temperature. In contrast to the abovementioned covering method, in this method the covering means is introduced in such a way that it projects beyond the outer surface of the component at an outlet opening of the respective cooling hole.

Furthermore, it is from the US 6,042,879 A known to first expand the cooling holes before applying the new coating, such that the subsequent coating by the penetration of the coating material into the cooling holes reduces the cross section of the cooling holes more or less to a desired target cross-section. That such a procedure is subject to extreme tolerances, is obvious.

From the US 2004/0134897 A1 a method is known, with the aid of which it is possible to provide temperature-stressed components after a certain period of operation again with a thermal barrier coating (thermal barrier coating). By applying this layer cooling air channels are closed, which are then reopened by a laser drilling with a conical laser beam. A disadvantage of this method is that the flow characteristics of the newly created cooling air hole in the layer depend on the layer thickness and therefore can not be guaranteed under all circumstances, that at the thermally highly stressed points of the component provided with cooling air openings after work-up the required amount of cooling air to form a Air film is blown out.

From the DE 698 07 892 T2 a method for working up a thermally highly stressed component is known, which is very expensive and also does not ensure that the flow characteristics of the cooling air holes of a reconditioned component correspond exactly to those of a new part.

Presentation of the invention

This is where the present invention begins. The invention, as characterized in the claims, deals with the problem of providing for a method of the type mentioned in an improved embodiment, which is characterized in particular by an increased lifetime of the repaired or renewed cooling hole.

According to the invention, this problem is solved by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea to carry out the repair or renewal of the cooling holes so that the cooling holes then have substantially the same cross-sections or substantially the same cross-sectional characteristics, as in the original unused state of the finished component. At the same time, however, a longitudinal section of the respective cooling hole, which extends to the outside of the component, should also be provided with the new coating. The restoration of the original geometry of the cooling hole ensures that the cooling hole can fulfill its intended function optimally. At the same time this reduces the risk that hot working gas can penetrate into the cooling hole. In addition, the reaching into the longitudinal section of the cooling hole new coating provides intensive protection of the material of the component from the aggressive hot working gases, if they should penetrate into the respective cooling hole. In this way, corrosion of the cooling hole and thus a cross-sectional expansion can be avoided. A cooling hole cross-section which widens due to corrosion during operation of the gas turbine facilitates the penetration of the aggressive working gas into the cooling hole and thereby increases the corrosive effect, which leads to an increased further cross-sectional widening.

With the aid of the repair process of the present invention, the repaired cooling holes have at least the same, if not better, resistance to the aggressive hot working gases of the gas turbine.

For realizing the invention, on the one hand, the removal of the at least one old coating is carried out such that subsequently the borehole has an old cross-section or old cross-sectional profile at least in said longitudinal section whose opening width is greater than a desired cross-section or desired cross-sectional profile that the borehole has when new with unused component. This is the case when the coating is removed, since, during use of the component, a widening of the borehole in said longitudinal section regularly occurs, for example due to the corrosive action of the working gases. Subsequently, the coating with the at least one new coating is selectively carried out such that the longitudinal section of the cooling hole has an intermediate cross-section or intermediate cross-sectional profile whose opening width is smaller than in the desired cross-section or desired cross-sectional profile. In this way, it is ensured that during the subsequent "drilling" of the individual cooling holes, the original desired cross-section or desired cross-sectional profile can be produced again. In the invention, this "drilling" is realized by a partial removal of the new coating within the cooling hole, such that the cooling hole then in the longitudinal section and in particular in the new coating penetrating hole region has a Neu-cross-section or new cross-sectional profile, which in Substantially corresponds to the desired cross-section or the desired cross-sectional profile.

The partial removal of the new coating is suitably carried out with a suitable laser method. Laser ablation methods or laser milling and / or drilling methods are particularly suitable for this purpose.

For the new coating, which extends into the longitudinal section of the cooling hole, it is expedient to use an oxidation and / or corrosion protection layer.

The problem underlying the invention is accordingly also solved by a component of a gas turbine having at least its cooling hole, which is likewise coated in a longitudinal region adjoining the outside of the component, the cooling hole otherwise providing a desired nominal cross section along its entire length or has a desired cross-sectional profile.

Other important features and advantages of the present invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

Brief description of the drawings

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

Show, in each case schematically,

1A to 1E each a cross section through a component in the region of a cooling hole at different states (A to E),

2A to 2E Views like in the 1A to 1E but in another embodiment of the cooling hole,

3A to 3E Views like in the 1A to 1E but in another embodiment of the cooling hole.

Ways to carry out the invention

The 1A . 2A and 3A each show a component 1 a gas turbine, not shown otherwise, on its outside 2 provided with at least one coating. In the preferred embodiment shown here, the component is 1 each with two coatings, namely with a first coating 3 and a second coating 4 Mistake. While the first coating 3 on the component 1 Applied is the second coating 4 on the first coating 3 applied. In another embodiment, the component 1 have only a single coating or even more than two coatings. The inventive method is then applicable accordingly.

The respective sections of the component shown 1 are with a cooling hole 5 Mistake. It is clear that the component 1 basically more than one such cooling hole 5 can have.

At the component 1 For example, it may be a bucket or a vane or a heat shield element or other cooled component. Every cooling hole 5 leads from a cavity, not shown, inside the component 1 to the outside 2 , In addition, the respective cooling hole 5 through the coatings 3 . 4 through to an outer skin 10 the coated component 1 extended.

At the first coating 3 it is expedient to an oxidation and / or corrosion protection layer. Such an oxidation and / or corrosion protection layer may be formed for example by a metal coating, in particular MCrAlY. M is at least one member of the following group: iron (Fe), copper (Cu) and cobalt (Co) and combinations thereof. In contrast, the second coating is 4 preferably around a heat protection layer. Such a heat protection layer can be achieved for example by a ceramic coating, which consists for example of zirconium oxide. The oxidation and / or corrosion protection layer, ie the first coating 3 may for example have a layer thickness of 150 microns to 300 microns. In contrast, the heat protection layer, so the second coating 4 preferably have a layer thickness of about 200 microns to 500 microns.

In the 1A . 2A and 3A is the component 1 in an original new condition, they after their coating with the layers 3 and 4 and after the introduction of the cooling holes 5 having. In this new condition has each cooling hole 5 a desired target cross-section or a desired target cross-sectional profile in the longitudinal direction of the cooling hole 5 , The nominal cross section is in the 1A . 2A and 3A With 6 designated during the desired cross-sectional profile with 7 is designated.

The embodiments of the 1 . 2 and 3 differ by the design of the cooling holes 5 , In new condition has the cooling hole 5 in the embodiments of the 1A and 2A in its longitudinal direction a constant nominal cross-section 6 , The nominal cross section 6 may be circular, for example. In contrast, in the embodiment according to 3A the cooling hole 5 with a desired cross-sectional profile 7 provided, leading to an outlet opening 8th the cooling hole 5 widens. The outlet opening 8th located at the downstream end of within the component 1 extending cooling hole 5 and is thus at the level of the outside 2 the component 1 , For the coated component 1 is however the cooling hole 5 through the coatings 3 . 4 extended through, which also extends the outlet opening to the outer skin 10 the coated component 1 , ie to the outside of the second coating 4 shifts. This outer outlet opening is below with 8th' designated.

For example, this can be an aerodynamically shaped exit area 9 within the component 1 or within the coatings 3 . 4 be achieved. An aerodynamically designed exit area 9 For example, it improves the formation of a cooling film that adheres to the outer skin during operation of the gas turbine 10 the coated component 1 applies and thereby the cooling effect or the thermal insulation of the coated component 1 improved. Other aerodynamically designed exit areas 9 are for example from the US 6,183,199 B1 , from the US 4,197,443 A and from the EP 0 228 338 B1 the contents of which are hereby incorporated by express reference into the disclosure of the present invention.

The embodiments of the 2A and 3A also differ from those of 1A in that the longitudinal direction of the cooling holes 5 in the embodiments of the 2A and 3A to a normal direction of the outside 2 while inclined in the embodiment according to 1A runs parallel to the normal direction. In the embodiment of the 2A has the longitudinal direction of the cooling hole 5 For example, an angle of about 45 °, while the angle of attack in the embodiment according to 3A is only about 30 °, but by the widening exit area 9 increases to about 60 °.

The for the new condition of the component 1 intended target cross section 6 or the desired cross-sectional profile 7 is designed for optimal cooling while optimizing performance and optimized gas turbine efficiency. The nominal cross section 6 or the desired cross-sectional profile 7 is manufactured within relatively narrow tolerance limits.

During operation of the gas turbine, the coatings wear out 3 . 4 , in particular in the field of cooling holes 5 , The 1B . 2 B and 3B each show a state at a time at which repair or renewal of the cooling holes 5 advisable. This time is, for example, approximately in the middle of the gas turbine or for its component 1 foreseen lifetime. The 1B . 2 B and 3B is clearly removable, that not only the outer second protective layer 4 , but also the inner first protective layer 3 as well as the cooling hole 5 laterally enclosing hole wall 15 at least in a longitudinal section 11 the cooling hole 5 is worn away. This longitudinal section 11 joins the outside 2 the component 1 and is indicated in the figures by a curly bracket.

Due to the removal of material in the coatings 3 . 4 as well as within the component 1 in the longitudinal section 11 gets the cooling hole 5 at least in the longitudinal section 11 as well as within the coatings 3 . 4 an enlarged cross section 6 ' or an expanded cross-sectional profile 7 ' , The original contour of the cooling hole 5 and the coatings 3 . 4 , that is the nominal cross section 6 or the desired cross-sectional profile 7 is in the 1B . 2 B and 3B each indicated by a broken line.

To those in the 1B . 2 B and 3B shown cooling holes 5 To repair or renew, the inventive method is carried out, which is explained in more detail below:
In a first process step, the old coatings 3 . 4 from the outside 2 the component 1 removed, at least in a hole area 12 , the cooling hole 5 surrounds. This hole area 12 extends in the figures each over the entire illustrated section of the component 1 , In the 1C . 2C and 3C is the original contour of the cooling hole 5 as well as the coatings 3 . 4 indicated by a broken line.

Removing the old coatings 3 . 4 can be carried out in a conventional manner, for example by means of an acid or by means of a corrosive solution. After removing the old coatings 3 . 4 has the cooling hole 5 in the longitudinal section 11 an old cross section 13 or an old cross-sectional profile 14 on. This old cross section 13 or the old cross-sectional profile 14 can with the widened cross-section 6 ' or cross section 7 ' in the 1B . 2 B and 3B shown state of use match. In principle, however, it is possible that the process of removing the old coatings 3 . 4 leads to an expansion of the cross-section or the cross-sectional profile, which is the case, for example, if with the removal of the old coatings 3 . 4 at the same time corrosion or oxidation deposits on the cooling hole 5 laterally delimiting perforated wall 15 also be removed. In the latter case, then the old cross section 13 or the old cross-sectional profile 14 by the process of removing the old coatings 3 . 4 influenced. In any case, the old cross-section is 13 greater than the nominal cross section 6 , Also is the old cross-sectional profile 14 further than the nominal cross-sectional profile 7 ,

In a second step of the method according to the invention, at least one new coating is applied to the component 1 applied. In the present example, two coatings are again applied, namely a new first coating 3 ' directly on the component 1 is applied, as well as a new second coating 4 ' that on the new first coating 3 ' is applied. The new first coating 3 ' this corresponds expediently to the original (old) first coating 3 , Correspondingly, the new second coating corresponds 4 ' expedient of the original (old) second coating 4 , It is clear that the new coatings 3 ' and 4 ' consider any technological advancement in coating technology that may have occurred since the date of the original new condition in accordance with 1A . 2A and 3A and the time the repair took place.

Attaching the new coatings 3 ' . 4 ' For example, it may be carried out by a high-temperature spraying method such as plasma spraying. For attaching the new coatings 3 ' . 4 ' It may also be expedient between the application of the new first coating 3 ' and attaching the new second coating 4 ' perform a high temperature treatment, for example, a diffusion bond between the materials of the new first coating 3 ' and the component 1 manufacture.

According to the 1D . 2D and 3D becomes the first new coating 3 ' so applied that they are right down to the cooling hole 5 extends, at least in the longitudinal section 11 , Furthermore, this coating process is carried out so that in the longitudinal section 11 as well as within the new coatings 3 ' . 4 ' So in the hole area 12 an intermediate cross section 16 or an intermediate cross-sectional profile 17 which is smaller than the original desired cross section 6 or desired cross-sectional profile 7 , The new second coating 4 ' It can also get into the cooling hole 5 into it and in addition to the new first coating 3 ' build up, creating the intermediate cross-section 16 or the intermediate cross-sectional profile 17 additionally narrows.

As in 2D can be shown when applying the new coatings 3 ' . 4 ' the intermediate cross section 16 shrink in some places to the value zero, that is, the new coating 3 ' . 4 ' closes the cooling hole 5 Completely.

After making the new coatings 3 ' . 4 ' Now follows in accordance with the method according to the invention in a third step, a partial removal of the new coatings 3 ' . 4 ' from the hole wall 15 , This partial removal of the new coatings 3 ' . 4 ' is done so that the cooling hole 5 then according to the 1E . 2E and 3E at least in the longitudinal section 11 as well as in the hole area 12 that is within the new coatings 3 ' . 4 ' a new cross section 18 or a new cross-sectional course 19 having. Partial removal of the new coatings 3 ' . 4 ' is specifically carried out so that the new cross-section 18 or the new cross-sectional course 19 about the same size as the nominal cross section 6 or the desired cross-sectional profile 7 , Because the old cross-section 13 or the old cross-sectional profile 14 has a larger opening width than the desired cross-section 6 or the desired cross-sectional profile 7 , is the component 1 in the longitudinal section 11 the cooling hole 5 with the material of the new first coating 3 ' Mistake. Accordingly, along the longitudinal section 11 the hole wall 15 through the into the cooling hole 5 projecting area of the new first coating 3 ' educated.

Because the cooling hole 5 after its repair or after its renewal has substantially the same dimension and shape as in the new state, can thus achieve the originally intended cooling performance during operation of the gas turbine again. At the same time a high efficiency and a high power output of the gas turbine are again achieved as in new condition. It is particularly advantageous that the hole wall 15 at least in the region of the longitudinal section 11 with the material of the new first coating 3 ' is coated, causing the hole wall 15 Protected against corrosion, when entering the aggressive hot working gases in the cooling hole 5 can occur. The durability of the repaired cooling hole 5 is thus at least equal to or even greater than the lifetime of the original cooling hole 5 in new condition of the component 1 ,

The 1E . 2E . 3E thus show a component 1 with repaired cooling hole 5 that differ from the original component 1 when new, it differs in that the new first coating 3 ' to the longitudinal area 11 hineinerstreckt.

To the new coatings 3 ' . 4 ' in the area of the cooling hole 5 To be able to remove partially, a laser method is preferably used. In this case, for example, a laser milling and / or drilling process comes into question. Such a laser milling and / or drilling method is distinguished, for example, by laser pulse energies which lie in a range from 1 J to 60 J. Pulse times in the range of 0.1 ms to 20 ms can occur, which corresponds to pulse frequencies in the range of 50 Hz to 10 kHz.

The laser ablation method used is characterized in particular by pulse times which lie in the range from approximately 10 μs to 1000 μs. This corresponds to pulse frequencies in the range of about 1 kHz to 100 kHz. In the laser ablation method, the energy density in the individual pulse is considerably greater than in laser milling or laser drilling. This can in particular a re-solidification of the melted areas of the new coating to be replaced 3 ' . 4 ' be avoided. Accordingly, the laser ablation process results in an extremely clean new cross-sectional shape 19 ,

The laser method can be controlled according to an advantageous embodiment by means of a cross-sectional measuring device which operates in particular galvanically.

Of course, the method according to the invention can also be applied to one component 1 Perform the several cooling holes 5 in which case it is then in particular possible to apply the method to a plurality of cooling holes 5 at the same time execute or offset from each other with respect to the individual process steps.

LIST OF REFERENCE NUMBERS

1

component

2

Outside of 1

3

old) first coating

3 '

new first coating

4

old) second coating

4 '

new second coating

5

cooling hole

6

Target cross section

6 '

cross-section

7

Target cross-sectional profile

7 '

Cross-sectional profile

8th

Outlet opening at 1

8th'

Outlet opening at 10

9

exit area

10

shell

11

Longitudinal section of 5

12

hole section

13

Alt-section

14

Alt-cross course

15

Pegboard

16

Intermediate section

17

Intermediate cross-sectional profile

18

New section

19

New cross-sectional profile

Claims (7)

Method for repairing or renewing cooling holes ( 5 ) of a coated component ( 1 ) of a gas turbine, comprising the following steps: removing at least one old coating ( 3 . 4 ) from an outside ( 2 ) of the component ( 1 ) at least in one the cooling hole ( 5 ) enclosing hole area ( 12 ), whereby the cooling hole ( 5 ) at least after removing the at least one old coating ( 3 . 4 ) at least in one to the outside ( 2 ) of the component ( 1 ) subsequent longitudinal section ( 11 ) an old cross section ( 13 ) which is greater than a desired cross-section ( 6 ) the cooling hole ( 5 ) in an original new condition of the finished component ( 1 ) in this longitudinal section ( 11 ), - attaching at least one new coating ( 3 ' . 4 ' ) on the component ( 1 ) at least in the hole area ( 12 ) and at least in the longitudinal section ( 11 ) of the cooling hole ( 5 ), such that the cooling hole ( 5 ) at least in the longitudinal section ( 11 ) and / or in the hole area ( 12 ) an intermediate cross section ( 16 ) which is smaller than the nominal cross-section ( 6 ), - partial removal of the at least one new coating ( 3 ' . 4 ' ) within the cooling hole ( 5 ) using a laser method, characterized in that the cooling hole ( 5 ) at least in the longitudinal section ( 11 ) and / or in the hole area ( 12 ) a new cross section ( 18 ) which is approximately the same size as the desired cross section ( 6 ) that the laser method is designed as a laser ablation method and operates at pulse frequencies in the range of 1 kHz to 100 kHz. A method according to claim 1, characterized in that the laser method is controlled by means of a, in particular galvanic, cross-sectional measuring device. Method according to one of claims 1 or 2, characterized in that - when removing the at least one old coating applied to the component old oxidation and / or corrosion protection layer ( 3 ) and one on the oxidation and / or corrosion protection layer ( 3 ) applied old heat protection layer ( 4 ), and / or - that when applying the at least one new coating, a new oxidation and / or corrosion protection layer ( 3 ' ) in the hole area ( 12 ) and in the longitudinal section ( 11 ), and / or - that after the application of the new oxidation and / or corrosion protection layer 3 ' a new heat protection layer 4 ' at least in the hole area ( 12 ) on the oxidation and / or corrosion protection layer 3 ' is applied, and / or - that as a new oxidation and / or corrosion protection layer ( 3 ' ) a metal coating is used, and / or - that as a new oxidation and / or corrosion protection layer ( 3 ' ) an MCrAlY coating is used, wherein M is at least one member from the following group: iron, copper, cobalt and combinations thereof and / or - that as a new heat protection layer ( 4 ' ) a ceramic coating is used, and / or - that as a new heat protection layer ( 4 ' ) a zirconium oxide coating is used, and / or - that the new oxidation and / or corrosion protection layer ( 3 ' ) is applied with a layer thickness of about 150 microns to 300 microns, and / or - that the new heat protection layer ( 4 ' ) is applied with a layer thickness of about 200 microns to 500 microns. Method according to one of claims 1 to 3, characterized - that the method for repairing or renewing such cooling holes ( 5 ) used in the component ( 1 ) and / or in the at least one coating ( 3 . 4 ) along its length a constant nominal cross section ( 6 ), and / or - that the method for repairing or renewing such cooling holes ( 5 ), which is one opposite a normal to the outside ( 2 ) of the component ( 1 ), and / or - that the method for repairing or renewing such cooling holes ( 5 ) used in the component ( 1 ) and / or in the at least one coating ( 3 . 4 ) an aerodynamically shaped exit area ( 9 ) with varying nominal cross section ( 6 ), and / or - that the method for repairing or renewing such cooling holes ( 5 ) used in the component ( 1 ) and / or in the at least one coating ( 3 . 4 ) to an outlet opening ( 8th . 8th' ) widening nominal cross section ( 6 ) exhibit. Method according to one of claims 1 to 4, characterized in that - the cooling hole ( 5 ) after removing the at least one old coating ( 3 . 4 ) in the longitudinal section ( 11 ) in the longitudinal direction of the cooling hole ( 5 ) an old cross-sectional profile ( 14 ) whose individual altitudinal cross-sections ( 13 ) are larger than the associated desired cross sections ( 6 ) of a desired cross-sectional profile ( 7 ) in this longitudinal section ( 11 ), and / or - that the cooling hole ( 5 ) after attaching the at least one new coating ( 3 ' . 4 ' ) in the longitudinal section ( 11 ) and / or in the hole area ( 12 ) in the longitudinal direction of the cooling hole ( 5 ) an intermediate cross-sectional profile ( 17 ), whose individual intermediate cross-sections ( 16 ) are smaller than the associated desired cross sections ( 6 ) of a desired cross-sectional profile ( 7 ), and / or - that the cooling hole ( 5 ) after the partial removal of the at least one new coating ( 3 ' . 4 ' ) in the longitudinal section ( 11 ) and / or in the hole area ( 12 ) in the longitudinal direction of the cooling hole ( 5 ) a new cross-sectional course ( 19 ), whose individual new cross-sections ( 18 ) are approximately the same size as the associated desired cross sections ( 6 ) of a desired cross-sectional profile ( 7 ). Method according to one of claims 1 to 5, characterized in that the method in a component ( 1 ), which have several cooling holes ( 5 ), at several cooling holes ( 5 ) is performed offset in time simultaneously or with respect to the individual process steps. Coated component ( 1 ) of a gas turbine, with at least one cooling hole ( 5 ), which in one on an outside ( 2 ) of the component ( 1 ) adjacent longitudinal area ( 11 ) and / or in a cooling hole ( 5 ) enclosing hole area ( 12 ) a desired cross section ( 6 ) or in its longitudinal direction a desired cross-sectional profile ( 7 ), the cooling hole ( 5 ) in an original new condition of the finished component ( 1 ), wherein a coating ( 3 ' ) of the component ( 1 ) at least to the longitudinal region ( 11 ), characterized in that the coated component ( 1 ) of a gas turbine according to one of the preceding methods.

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