The present invention relates to a method for producing a welded joint for components of a turbine-type machine, in particular for repairing components, as recited in the preamble of claim 1.
The German Patent DE 42 25 443 C2 describes a method for producing a welded joint for components of a turbine-type machine, in particular for use in repairing a blade of a gas turbine blade; to this end, a damaged portion being removed from the blade of the gas turbine blade and being replaced by a replacement part. The replacement part is also referred to as a patch. In accordance with the German Patent DE 42 25 443 C2, a pocket-like recess is introduced into the replacement part, the pocket-like recess facilitating placement of the replacement part on the blade of the gas turbine blade to be repaired. The German Patent DE 42 25 443 C2 discusses filling a gap, which forms in the area of the pocket-like recess between the replacement part and the blade of the gas turbine blade to be repaired, with metal powder in order to weld the two components together. Here defects can form in the weld seam, and internal stresses can likewise be introduced into the components that are to be joined together.
Against this background, an object of the present invention is to devise a novel method for producing a welded joint for components of a turbine-type machine, in particular for use in repairing a component. This objective is achieved by a method as set forth in claim 1. In accordance with the present invention, in addition to the pocket-like recess, at least one cutout is introduced into the first component in order to minimize a dissipation of heat and the development of component deformations during the subsequent process of welding the components together.
Accordingly, besides the pocket-like recess, the present invention also provides that a material cutout or a plurality of material cutouts be introduced into the first component that is preferably being used as a replacement part. By introducing the cutout, respectively the cutouts, into the first component, it is possible to prevent an uneven temperature distribution along the weld seam to be formed. Accordingly, the formation of defects at the weld seam is minimized. In addition, the development of internal stresses and thus of component deformations is minimized during the process of welding the components together.
A first cutout is preferably introduced into a side wall of the first component opposite the pocket-like recess, this first cutout having a step-shaped or rounded contour and extending essentially in the direction of a weld seam to be formed between the components.
Second cutouts are preferably introduced into the side walls of the first component bounding the pocket-like recess, these second cutouts having a slit- or slot-type contour and extending essentially transversely to the direction of the weld seam to be formed.
One advantageous refinement of the present invention provides for a pocket-like recess, whose contour is adapted to the contour of an end portion of the second component to be inserted into the same, to be introduced into the first component in such a way that when the first component is slipped onto the second component, a gap of such a minimal size is formed between the pocket-like recess of the first component and the end portion of the second component that the components rest flush against one another in the region of the pocket-like recess. This makes it possible for the quality of the welded joint to be further enhanced as compared to the method known from the related art. In particular, this prevents defects from forming and internal stresses from being introduced into the components that are to be joined together.
Preferred embodiments of the present invention are derived from the dependent claims and from the following description. The present invention is described in greater detail in the following on the basis of exemplary embodiments, without being limited thereto. Reference is made to the drawing, whose:
The present invention is directed to a method for producing a welded joint for components of a turbine-type machine. The method is used, in particular, for repairing components of gas turbine blades in the area of one blade; to this end (see
To repair a gas turbine blade 11 using the method according to the present invention, as already mentioned, a damaged blade portion is first separated from blade 10 of gas turbine blade 11 to be repaired. This damaged blade portion is to be replaced by a replacement part 12, also referred to as a patch, by welding replacement part 12 to remaining blade 11. Once the components have been welded, a surface machining of at least replacement part 12 is carried out in order to produce surfaces having the desired aerodynamic properties on blade 10.
Remaining blade 11 is measured, at least a section thereof, namely at least in the area of a separation region formed by separating the damaged blade portion; as a function thereof, a pocket-like recess 13 (see
Pocket-like recess 13 introduced into the replacement part may be contoured to have an essentially uniform material thickness along a weld seam line, along which replacement part 12, as well as blade 10 are joined together. This allows substantially constant welding parameters to be used when welding along the weld seam line.
Recesses in the form of slits and/or slots and/or steps and/or round contours and/or bores are introduced into replacement part 12, namely into the external surfaces of side walls thereof. This makes it possible to minimize a dissipation of heat from components 11, 12 to be joined together and to maintain a substantially constant process temperature for welding during the entire welding process. By introducing the slits and/or slots and/or steps and/or round contours and/or bores into replacement part 12, it is possible to prevent replacement part 12 from being deformed during the welding process. This enhances the attainable welding quality.
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It may be provided in a welding operation for components 11, 12, which are to be joined together, to be preheated to a process temperature with the aid of a heat source, prior to the actual welding process; during the welding, the two components 11, 12 likewise being maintained at the process temperature through the use of a heat source. Upon termination of the welding process, the components that have been joined together may also undergo a postweld heating. As a heat source, an inductive heat source, an electrical heating spiral, or a laser may be used, for example.
As already mentioned, prior to formation of the weld seam, replacement part 12 is slipped via pocket-like recess 13 onto blade 10 to be repaired, from which the damaged blade portion had been removed. Once it has been slipped on, replacement part 12 may be positioned on blade 10 with the aid of tack welds. Specially designed retaining devices may also be used to arrange replacement part 12 on blade 10 and hold it in place during welding. Run-on, as well as runoff plates may also be integrated in replacement part 12 for the weld seam.
If the replacement part is a patch that extends between a leading edge, respectively a trailing edge of the blade and a blade tip thereof, the weld seam may then extend in any desired manner, namely, on one side, from the leading edge, respectively the trailing edge, to the blade tip or also the other way around, from the blade tip to the leading edge or trailing edge of the blade.
The method according to the present invention makes it possible to optimize the process of using a welded joint to join components together. In particular, it allows constant welding parameters to be used when producing welded joints on components of a gas turbine. The formation of defects, as well as the introduction of internal stresses into the components that are to be joined together are minimized during the welding process. Overall, therefore, the welding quality may be enhanced.
Number | Date | Country | Kind |
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10 2005 051 229.1 | Oct 2005 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/DE2006/001831 | 10/17/2006 | WO | 00 | 2/27/2009 |