METHOD FOR REPAIRING A COMPONENT

Abstract

A method for repairing a component is provided, including the following steps: introducing a recess into the component, via which recess a damaged region in the component is removed; positioning a filler body in the recess; and fixedly, i.e. non-detachably, connecting the filler body to the component, wherein the filler body is provisionally secured to the component prior to establishing the fixed connection to the component, in that a securing element is placed over the filler body and the securing element is attached to the component, wherein the securing element is removed again after the establishing of the fixed connection between the filler body and the component.

Claims

1-15. (canceled)

16. A method for repairing a component, comprising: creating a recess in the component, by means of which a damaged region in the component is removed, positioning a plug in the recess; and permanently connecting the plug to the component; wherein, prior to creating a permanent connection with the component, the plug is provisionally secured to the component by a securing element being laid over the plug and the securing element being attached to the component, the securing element being removed once the permanent connection between the plug and the component has been established, and in which use is made of an elongate securing element.

17. The method as claimed in claim 16, wherein the securing element which has a thickness of less than 1 mm.

18. The method as claimed in claim 16, wherein the securing element made of a foil.

19. The method as claimed in claim 17, wherein the securing element is a foil strip having a thickness in the range from 0.08 mm to 0.12 mm.

20. The method as claimed in claim 16, wherein the securing element is made of a material whose thermal expansion coefficient is lower than a thermal expansion coefficient of the material of the component and/or of the plug.

21. The method as claimed in claim 16, wherein the securing element is made of molybdenum or a molybdenum alloy.

22. The method as claimed in claim 16, wherein the component is made of a nickel-based component and is repaired using the plug made of a nickel-based plug.

23. The method as claimed in claim 16, wherein the securing element is attached to the component by spot-welding.

24. The method as claimed in claim 23, wherein two free ends of the securing element are attached to the component by creating at least one spot-weld connection.

25. The method as claimed in claim 16, wherein two or more securing elements are laid over the plug and are attached to the component in order to provisionally secure the plug to the component.

26. The method as claimed in claim 16, wherein once the securing element has been removed, the component is finished in at least one region in which the securing element was attached to the component.

27. The method as claimed in claim 16, wherein the securing element is additionally attached to the plug and, once the securing element has been removed, the plug is finished in at least one region in which the securing element was attached to the plug.

28. The method as claimed in claim 16, wherein a shape of the plug matches a shape of the recess.

29. The method as claimed in claim 16, wherein the plug is permanently connected to the component by a high-temperature soldering process.

Description

BRIEF DESCRIPTION

[0044] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0045] FIG. 1 is a schematic representation of a component that is to be repaired, with a plug which is positioned in a recess and is provisionally attached to the component by means of two securing elements, in the manner according to embodiments of the invention; and

[0046] FIG. 2 is a sectional representation of the component shown in FIG. 1, showing the recess, the plug and the securing elements.

DETAILED DESCRIPTION

[0047] FIG. 1 shows, in a schematic representation, a component that is to be repaired, in the present case a turbine blade 1 made of a nickel-based base material.

[0048] The turbine blade 1 suffered damage during operation.

[0049] For that reason, for repair a prismatic recess 2 has been introduced into the turbine blade 1 by milling, by means of which the damaged region of the turbine blade 1 has been removed.

[0050] In order to re-fill the recess 2 created to remove the damage, and thus reproduce the original shape of the turbine blade 1, an also prismatic plug 3 made of a nickel-based material is positioned in the recess 2.

[0051] The plug 3 is dimensioned such that it is slightly narrower than the recess 2. Furthermore, the height of the plug 3 is dimensioned such that the plug 3 projects upward slightly out of the recess 2 when it is positioned in the recess 2 together with a soldering material, in this case a soldering foil 4. The soldering foil 4 is provided between the wall of the recess 2 and the plug 3, which is shown clearly in the sectional representation of FIG. 2.

[0052] In the context of repairing the turbine blade 1, a solid, i.e. permanent, connection is to be created between the plug 3 positioned in the recess 2 and the surrounding turbine blade 1. In the present case, there is provided for this a high-temperature soldering process which involves heating to approximately 1200° C. This causes the material of the soldering foil 4 to melt, thus creating a material-bonded join between the plug 3 and the turbine blade 1.

[0053] It has proven difficult to keep the plug 3 in its desired position during the soldering process.

[0054] In order to prevent undesired slipping of the plug 3 in the recess 2, embodiments of the invention provides that, prior to creating the solid connection between the turbine blade 1 and the plug 3, the latter is provisionally secured by means of two securing elements 5.

[0055] Specifically, each of the two securing elements 5 are elongate foil strips made of molybdenum. In order to create the securing elements 5, a 0.1 mm-thick molybdenum foil was cut into strips. The securing elements 5 therefore each have a thickness of 0.1 mm.

[0056] The two securing elements 5 are placed over the plug 3 such that their longitudinal axes are oriented transversely to that of the plug 3. The securing elements 5 reach over the plug 3 in its transverse direction, and thus their longitudinal direction, entirely and each extend beyond the plug 3 on both longitudinal sides of the latter. In the regions projecting laterally beyond the plug 3, the two securing elements 5 are each spot-welded to the turbine blade 1 at two punctiform welding locations 6.

[0057] In that context, the two securing elements 5 are spot-welded to the turbine blade 1 such that there is no longer any play between these elements and the plug 3. They both bear against the upper side of the plug 3 and thus hold the latter in the recess 2.

[0058] Since the securing elements 5 have a thickness of just 0.1 mm, only a relatively very low current and a short holding time are required to spot-weld the securing elements 5 by spot-welding to the turbine blade 1 at the corresponding locations. Thus, once the securing elements 5 have been placed over the plug 3, they can be attached to the turbine blade 1 particularly rapidly and simply.

[0059] Once the securing elements 5 have been attached, a solid connection between the plug 3 and the turbine blade 1 can be created by means of a high-temperature soldering process.

[0060] Creating the solid connection involves heating to approximately 1200° C. in order to obtain the material-bonded join between the turbine blade 1 and the plug 3. Since molybdenum has a lower thermal expansion coefficient than the turbine blade 1 and the plug 3 made of the nickel-based material, the securing elements 5 secure themselves automatically during the soldering procedure. The plug 3 presses against the securing elements 5 due to its greater expansion with respect thereto. As a result, the plug 3 is particularly reliably held in the desired position in the recess 2.

[0061] After completion of the high-temperature soldering process, the securing elements 5 can be easily, for example manually, removed from the turbine blade 1. Since the relatively thin securing elements 5 can be attached to the turbine blade 1 in a particularly non-damaging manner by spot-welding, the turbine blade 1 suffers little or no damage in the regions of the punctiform welding locations 6. If necessary, these locations can optionally be briefly re-ground after removal of the securing elements 5 in order to once again obtain a particularly smooth surface of the turbine blade 1.

[0062] In the event that, after the end of the high-temperature soldering process, the plug 3 still projects slightly upward beyond the recess 2, it is moreover readily possible to once again smooth the surface of the turbine blade 1 by grinding or another type of finishing.

[0063] By using the method according to embodiments of the invention for repairing a component, it is possible to return the originally damaged turbine blade 1 to a fully functional state. In that context, the use, according to embodiments of the invention, of the securing elements 5 makes it possible to reliably hold the plug 3 in the desired position during creation of the solid connection between it and the turbine blade 1. This reliably avoids slipping of the plug 3, which can produce an unsatisfactory result after the soldering procedure.

[0064] Although the invention has been described and illustrated in detail by way of the preferred exemplary embodiment, the invention is not restricted by the disclosed examples and other variations can be derived herefrom by a person skilled in the art without departing from the scope of protection of the invention.

[0065] For the sake of clarity, it is to be understood that the use of ‘a’ or ‘an’ throughout this application does not exclude a plurality, and ‘comprising’ does not exclude other steps or elements.