EP2018244A1

EP2018244A1 - Method of repairing a component, and a component

Info

Publication number: EP2018244A1
Application number: EP07704601A
Authority: EP
Inventors: Fathi Ahmad; Michael Dankert
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2006-05-18
Filing date: 2007-02-15
Publication date: 2009-01-28
Also published as: EP1857218A1; US20090229101A1; WO2007134883A1

Abstract

In the repair of cracks according to the prior art, although the cracks are processed and filled with a braze alloy or a coupon, such a repaired component often does not have the desired mechanical high-temperature properties under the subsequent conditions of use. According to the invention, rods (22', 22'', 22''') which stop subsequent possible crack growth are present in the depression (11) around the crack (7).

Description

Method for repairing a component and a component

The invention relates to a method for repairing a component according to the preamble of claim 1 and a component according to claim 13.

Newly made, e.g. molded components or components often show cracks that are repaired to allow the component to be reused.

According to the state of the art, material is worked around the crack and filled or welded with a solder.

Likewise known from EP 0 868 253 B1 is the so-called coupon soldering.

However, the above-mentioned methods often can not sufficiently prevent the crack growth when using the component.

It is therefore an object of the invention to overcome the above-mentioned problem.

The object is achieved by a method according to claim 1 and a component according to claim 13.

The invention will be explained in more detail with reference to FIGS.

Further advantageous measures are listed in the subclaims, which can be combined with each other in an advantageous manner. Show it:

1 shows a component surface with a crack, Figure 2 is a sectional view of Figure 1 along the line II-II,

Figure 3 is a sectional view of a trough, Figure 4 is a surface of a component with a trough according to the invention according to the

Invention, Figure 5 shows the negative of the elaborated

Crack surface (trough),

FIG. 6 the use of bars in the further repair of the component,

Figure 7 is a sectional view of Figure 6 along the line VII-VIII

8, 9, 10, 11 further embodiments of the

Invention,

Figure 12, 13 a further arrangement possibility of

Bars in the hollow,

FIG. 14 a gas turbine, FIG. 15 a perspective view of a turbine blade, and FIG. 16 a perspective view of a combustion chamber.

Figure 1 shows a surface 4 of a component 1, the one

Has crack 7 with a length 1 along a crack direction 8. The crack 7 can also be curved, but even then has an (averaged) crack direction 8.

The component 1 is preferably a turbine blade 120, 130 (FIG. 14) or a combustor element 155 (FIG. 15) of a turbine, such as e.g. an aircraft turbine, preferably a gas turbine 100 (FIG. 13). Particularly in the case of turbine components, a substrate 10 of the component 1 consists of a nickel- or cobalt-based superalloy.

However, the method of crack repair is not limited to such components, but also includes all components with Cracks, blowholes, cavities that are repaired by soldering or welding and also those made of other materials.

Figure 2 shows a sectional view of Figure 1, from which it can be seen that the crack 7 has a crack depth a in the substrate 10 of the component 1, which has a thickness or wall thickness t has (a << t).

The crack 7 according to FIGS. 1, 2 is worked out as in the prior art, so that a depression 11 is formed, which according to the prior art has a rectangular (FIG. 3, 4, 5) or triangular (FIG , 9) recess. Other cross-sectional shapes are conceivable. The trough 11 is preferably cuboidal.

According to the invention, however, the trough 11 additionally has at least two recesses 13, 13 ', 16, 16', 19, 19 '. FIG. 4 shows a plan view of such a trough 11.

The recesses 13, 13 ', ... can be arranged along the direction 8 around the circumference of the trough 11 as desired. Preferably, the recesses 13, 13 ', ... arranged in pairs directly opposite each other (Fig. 4, 5, 6, 9, 10).

Preferably, the distances between the recesses 13, 13 ', 16, 16', ... and in particular to the beginning or the end 17 of the trough 11 are equidistant (Fig. 5, 6).

In the embodiment of Figure 4, the recesses 13, 13 'at the end 17 of the trough 11 are present.

In Figure 5, the negative of the carved inner surface of the trough 11 with recesses 13, 13 ', ... is shown.

Here, the recesses 13, 13 'are not arranged at the end 17 of the trough 11, but have a distance to an end 17 of the trough 11 along the direction 8. The finished trough 11 has a height a 'which is equal or substantially the crack depth a according to Figure 3 (a ≤ a'). The trough 11 has a length 1 'along the crack direction 8, which is equal or substantially equal to the length 1 of the crack 7 (Figure 1) (1 <1').

Furthermore, the trough 11 (without recesses) has a width b that is wide enough that the tear 7 and attacked surfaces on the tear surface have been removed.

The recesses 13, 16, 19, which preferably have opposite, in particular perpendicular to the cracking direction 8, recesses 13 ', 16', 19 ', represent quasi transverse to the direction 8 cuboid (see dashed lines) represents a length b + greater as the width b of the trough 11 have.

The recesses 13, 13 ', ... are here, for example, parallelepiped-shaped (or cube-shaped) and have a length f along the direction 8, a depth g in the direction of the depth a, and a width to the direction of the width b e. The width e of the recess is preferably significantly smaller than the width b of the trough 11, the length f is significantly smaller than the length 1 'of the trough 11 and the depth g is preferably significantly smaller than the depth a' of the trough 11th

In Figure 5, the recesses 13, 13 ', .... cube or cuboid shaped. Likewise, the recesses 13, 13 ', ... may have other shapes (round or triangular in cross-section).

After the crack has been worked out according to FIG. 5, rods 22 ', 22' ', 22' "are inserted into the recesses 13, 13 ',..., Whose melting temperature is higher than that

Melting temperature of the filling material, which in particular represents a Lot 25, which then still in the trough 11 to be filled is filled (Fig. 7). The trough 11 can also be welded shut.

The recesses 13, 13 'are preferably designed in such a way that the rods 22', 22 '', 22 '' 'can be inserted there from above, i. the recesses 13, 13 ', ... are open at the level of the surface 4, and these do not protrude beyond the surface 4 of the trough 11. The depth g of the recesses 13, 13 ',... Is here (FIG. 5) preferably designed so that the rod 22', 22 '', 22 '' 'is arranged near the surface 4 of the component 1.

The rods 22 ', 22' 'are preferably arranged in a plane, that is at a height. The height of the bars 22 ', 22' 'one below the other, ie the depth g of the respective recesses 13, 13' can also be chosen arbitrarily, so that a greater distance from the surface 4 is present.

Preferably, the material of the rods 22 ', 22' ', 22' '' of a ceramic material.

The effect of the bars is that a crack which often forms on the surface 4 and spreads in the solder hits the ceramic bars 22 ', 22' ', 22' "and there due to the higher toughness of the material the rods 22 ', 22' ', 22' '' is prevented from growing further.

Likewise, the recesses 13, 13 ', 16, 16', 19, 19 'may extend over the entire height a' of the trough 11, as shown in Figure 10.

In these recesses 13, 13 ', ... then preferably no rods, but plates are inserted, which extend over the entire width b +. The plates may have the height a ', but may also be made smaller.

Instead of plates also fine or coarse meshes can be inserted, so that the filler or the solder in the Soldering the net can enclose and the network over the entire depth of the trough 11 acts as a cracking obstacle.

Instead of the rods 22 ', 22' ', 22' '' can also fiber bundles and instead of the plates fiber mats can be inserted into the trough 11.

Likewise, a coupon can be soldered or welded into the trough 11, which has a shape according to Figure 5 and thereby has smaller dimensions than the trough 11 in order to be pushed into it.

FIG. 11 shows a further exemplary embodiment of an arrangement of the rods 22 ', 22 ", 22"' in the trough 11.

The rods 22 ', 22' ', ... do not run perpendicular to the crack direction 8 or to the longitudinal direction of the trough 11, but are arranged obliquely. Likewise, the bars 22 ", 22 '" may intersect, i. they are either arranged at different heights in the trough 11 or in the recesses 16, 16 ', 19, 19', a cross in the form of an "X" is inserted, wherein the rods 22 '' and 22 '' 'can form a part ,

Further arrangement possibilities with respect to the bars 22 ', 22 "with each other or the combination of bars and fiber mats (FIG. 10) are conceivable.

Instead of the recess, which adjoin the surface 4 of the component 1, also recesses 13, 13 ', ... below the surface 4 on the inner surfaces of the trough 11 may be present. The bars 22, ... must then be so flexible that they can be bent (Figure 12), so that they can be inserted into the trough 11 and the bars must have a length> b, so that both ends in the recesses 13, 13 'rest (Figure 13). FIG. 14 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, air 105 is sucked in by the compressor 105 through the intake housing 104 and compressed. The compressed air provided at the turbine-side end of the compressor 105 is supplied to the burners 107 where it is mixed 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. The working medium 113 relaxes on the rotor blades 120 in a pulse-transmitting manner, so that the 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 highest 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 may have a directional structure, i. they are monocrystalline (SX structure) or have only longitudinal grains (DS structure).

As the material for the components, in particular for the turbine blade 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; These documents are part of the disclosure regarding the chemical composition of the alloys.

The vane 130 has a guide vane foot (not shown here) facing the inner housing 138 of the turbine 108 and a vane head opposite the vane foot. The vane head faces the rotor 103 and fixed to a mounting ring 140 of the stator 143.

FIG. 15 shows a perspective view of a moving blade 120 or guide blade 130 of a turbomachine that extends along a longitudinal axis 121. 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 consecutively a fastening region 400, a blade platform 403 adjacent thereto and an airfoil 406 and a blade tip 415.

As a guide blade 130, the blade 130 may have at its blade tip 415 another platform (not shown).

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 designed, for example, as a hammer head. 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; These documents are part of the disclosure regarding the chemical composition of the alloy.

The blade 120, 130 can be made 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 that are in operation high mechanical, thermal and / or chemical stresses are exposed.

The production of such monocrystalline workpieces takes place e.g. by directed solidification from the melt. These are casting processes in which the liquid metallic alloy is transformed into a monocrystalline structure, i. to the single-crystal workpiece, or directionally solidified. Here, dendritic crystals are aligned along the warm flow and form either a prismatic crystalline grain structure (columnar, i.e. grains extending throughout the length of the work piece and here, in common parlance, referred to as directionally solidified) or a monocrystalline structure, i. the whole work consists of a single crystal. In these processes, it is necessary to avoid the transition to globulitic (polycrystalline) solidification, since non-directional growth necessarily forms transverse and longitudinal grain boundaries which negate the good properties of the directionally solidified or monocrystalline component. If the term "directionally solidified" is generally used, it means both single crystals which have no grain boundaries or at most small-angle grain boundaries, and also stem crystal structures which have grain boundaries that are probably in the longitudinal direction but no transverse grain boundaries. In these second-mentioned crystalline

Structures are also known as directionally rigidified joints

(directionally solidified structures).

Such methods are known from US Pat. No. 6,024,792 and EP

0 892 090 Al known; these writings are part of the disclosure with regard to the solidification process.

Likewise, the blades 120, 130 may have coatings against corrosion or oxidation, e.g. 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 silicon and / or at least one element of the rare ones Earth, or hafnium (Hf)). Such alloys are known from EP 0 486 489 B1, EP 0 786 017 Bl, EP 0 412 397 B1 or EP 1 306 454 A1, which should be part of this disclosure with regard to the chemical composition of the alloy. 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).

On the MCrAlX may still be present a thermal barrier coating, which is preferably the outermost layer, and consists for example of ZrÜ2, Y2Ü3 ZrÖ2, ie it is not, partially ^¬ or fully stabilized by yttria and / or calcium oxide and / or magnesium oxide. The thermal barrier coating covers the entire MCrAlX layer. Suitable coating processes, such as electron beam evaporation (EB-PVD), produce stalk-shaped grains in the thermal barrier coating.

Other coating methods are conceivable, e.g. atmospheric plasma spraying (APS), LPPS, VPS or CVD. The heat-insulating layer may have porous, micro- or macro-cracked grains for better thermal shock resistance. The thermal barrier coating is therefore preferably more porous than the MCrAlX layer.

The blade 120, 130 may be hollow or solid. If the blade 120, 130 is to be cooled, it is hollow and may still film cooling holes 418 (indicated by dashed lines) on.

FIG. 16 shows a combustion chamber 110 of the gas turbine 100. The combustion chamber 110 is designed, for example, as a so-called annular combustion chamber, in which a multiplicity of burners 107 arranged in the circumferential direction around a rotation axis 102 open into a common combustion chamber space 154, which produce flames 156 , 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. In order to enable a comparatively long service life even with these, for the materials unfavorable operating parameters, the combustion chamber wall 153 is provided on its side facing the working medium M side with an inner lining formed from 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.

Each heat shield element 155 made of an alloy is equipped on the working medium side with a particularly heat-resistant protective layer (MCrAlX layer and / or ceramic coating) or is made of high-temperature-resistant material (solid ceramic blocks).

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 silicon and / or at least one element of the rare earths, 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, which should be part of this disclosure with regard to the chemical composition of the alloy.

On the MCrAlX may still be present, for example, a ceramic thermal barrier coating and consists for example of ZrC> 2, Y2θ3-ZrC> 2, ie it is not, partially or fully ^¬ dig stabilized by yttrium 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.

Other coating methods are conceivable, e.g. Atmospheric plasma spraying (APS), LPPS, VPS or CVD. The thermal barrier coating may have porous, micro- or macro-cracked grains for better thermal shock resistance.

Refurbishment means that turbine blades 120, 130, heat shield elements 155 may need to be deprotected (e.g., by sandblasting) after use. This is followed by removal of the corrosion and / or oxidation layers or products. Optionally, even cracks in the turbine blade 120, 130 or the heat shield element 155 are repaired by the method according to the invention. Thereafter, a re-coating of the turbine blades 120, 130, heat shield elements 155 and a renewed use of the turbine blades 120, 130 or the heat shield elements 155 takes place.

Claims

claims

1. A method for crack repair of a component (1) having a crack (7) on a surface (4) of the component (1), wherein a trough (11) worked out around the crack (7) and wherein in a final method step Trough (11) is filled with a solder (25),

characterized in that

the trough (11) has at least two recesses (13, 13 ', 16, 16', 19, 19 ').

2. The method according to claim 1, characterized in that

the recesses (13, 13 ', 16, 16', 19, 19 ') are arranged at the level of the surface (4).

3. The method according to claim 1 or 2, characterized in that

the recesses (13, 13 ', ...) are arranged around the circumference of the trough (H).

4. The method according to claim 3, characterized in that

the recesses (13, 13 ', 16, 16', 19, 19 ') oppose in pairs on opposite sides of the trough (11).

5. The method of claim 1, 2, 3 or 4, characterized in that

the trough (11) is cuboidal.

6. The method of claim 1, 2, 3, 4 or 5, characterized in that

the trough (11) has a longitudinal direction parallel to the tear direction (8) of the crack (7).

7. The method according to claim 2, 3, 4, 5 or 6, characterized in that

the recesses (13, 13 ', 16, 16', 19, 19 ') run transversely, in particular perpendicularly, to a crack direction (8) of the crack (7) or a longitudinal direction of the trough (11) and, accordingly, the trough ( 11) at the height of the surface

(4) a larger width (b +) than a width (b) of the trough

(11) without recess.

8. The method of claim 1, 2, 3, 4, 5, 6 or 7, characterized in that

the recesses (13, 13 ', 16, 16') form a cuboid.

9. The method according to claim 2 or 8, characterized in that

the recesses (13, 13 ', ...) are formed so that by inserting rods (22', 22 '', 22 '' ') the rods (22', 22 '', 22 '' ') in are arranged near the surface (4) of the component 1, but do not protrude beyond the surface (4) of the component 1.

10. The method according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, characterized

that rods (22 ', 22' ', 22' '') in the recesses (13, 13 ',

...) are arranged and that then the trough (11) with a filling material, in particular with a solder (25), is filled, wherein the melting temperature of the rods (22 ', 22' ', 22' '') has a higher melting temperature than that of the filling material.

11. The method according to claim 9 or 10, characterized in that

the rods (22 ', 22' ', 22' '') are made of ceramic.

12. The method of claim 2, 3, 4, 5, 6, 7 or 8, characterized in that

a coupon is fixed in the trough (11), in particular soldered, which has a shape of the trough (11) with recesses (13, 13 ',.

3. Component produced according to one or more of the preceding claims.