WO2015078613A1 - Secure stop closure by diffusion coating and method - Google Patents

Abstract

A secure connection with respect to mechanical properties is achieved due to the use of a diffusion layer (10' 10'', 10''') between a stop and a substrate (4', 4'', 4''') in which the stop (7', 7'', 7''') is arranged.

Description

 Safe plug closure by diffusion coating and

 method

The invention relates to the closure by means of a plug by means of diffusion coating and a method for the production.

In the production of hollow gas turbine pipes by casting, both quartz and platinum pins are used to secure the cores during filling and solidification of the gas turbine

Keep the melt in the right position in the mold shell. Both technical approaches have both advantages and disadvantages.

Thus, after the leaching of the ceramic cores or the use of quartz pins, holes are formed in the blade walls. This does not occur when using platinum pins. However, these are again very expensive, which leads to a significant increase in unit costs.

In the case of a rotor blade, for example, due to the special manufacturing process core core holes can arise in the crown floor. These are often reclosed in a TIG welding process, if that is from the designed

Design is required. The disadvantage of every welding process is the tendency to form microcracks in the heat-affected zone or the like. in the weld metal. On solidification of the enamel bath, high internal stresses also occur, which must be removed by a suitable heat treatment. The cracks can have a life-reducing effect, since these are damaged by thermal and mechanical stress, for. B. grow during operation of the components and damage the components sustainably. Since such cracks must be avoided in blade tips for technical and commercial reasons, the closing of the holes by means of a welding process is not optimal. From the above-described facts, there is a need to develop a closure alternative of the core retaining holes. Holes in components can in principle be closed by a wide variety of approaches. However, the challenges of this problem can be found in the high thermal, corrosive / oxidative and mechanical loads that can act on the turbine blades during startup and shutdown and during operation of the gas turbine.

It is therefore an object of the invention to solve the above problems. The object is achieved by a plug according to claim 1 and a method according to claim 8.

It is proposed to use a mechanical closure, which is connected to the component by means of a firmly adhering diffusion layer.

As the diffusion layer, chromium is preferably proposed because chromium is an alloying element used in nickel-base superalloys and also generally constitutes a suitable oxide layering agent in steels. The forming oxide layer protects against further corrosive and oxidative attacks. In addition, it is assumed that due to the larger specific volume, the chromium oxide layer mechanically clamps the plug.

The stopper can thus be rotated before being introduced into the hole. After introducing the chromed plug, the formation of the chromium diffusion layer between the component and plug is initiated by a corresponding heat treatment, in particular in a standard subsequent heat treatment at about 1273K. In the dependent claims further advantageous measures are listed, which can be combined with each other in order to achieve further advantages. Ceramic cores almost always have to be held in place by various methods for the manufacture of hollow gas turbine blades, which may result in holes in the component walls. The proposed solution takes into account both the mechanical requirements, as well as the corrosion-oxidation protection and the chemical compatibility.

Advantages of the invention presented here:

 - Fixation of the closure

 - Cost effective and simple procedure

 - The compound is corrosion-protected

 - Same thermal expansion through similar plugs

- Shutter survives several revision periods

 - Mechanically strong connection. Show it:

Figure 1, 2, 3 embodiments of the invention and

Figure 4 is a list of superalloys. The figures and the description represent only embodiments of the invention.

FIG. 1 shows a component 1 'with a substrate 4'.

The substrate 4 ^λ , 4 ^{λ λ} , 4 '''(Figures 2, 3) is preferably a wall of a hollow member such as a turbine blade, and preferably has a nickel- or cobalt-based

Superalloy, in particular one according to Figure 4.

The substrate 4 ^λ , 4 '4 ^N has a hole 8 8' 8 ^{λ λ λ} , in particular a through hole 8 ^λ , 8 ", 8 '(Fig. 2, 3), which is to be closed. The hole 8 ^λ , 8 ^{λ λ} , 8 '''is closed by a plug 7 7 ^{λ λ} , Ί (Fig. 2, 3). In this case, the hole 8 'and, accordingly, the plug 7' is formed as a thread (FIG. 1).

In this case, preferably the substrate 4 ^λ , 4 ^{λ λ} , 4 '''in the hole 8 ^λ , 8 ^{λ λ} , 8''' and / or the plug 7 'with a diffusion layer 10 10 ^{λ λ} , 10 ^{λ λ λ} (Fig. 2, 3) provided.

Likewise, as an alternative between the contact surfaces of the plug 7 'and the substrate 4' within the hole 8 ', a diffusion material can be introduced, which leads by heat treatment to a diffusion layer.

 The diffusion material is selected depending on the material of the substrate 4 '.

For nickel- or cobalt-based substrates 4 ^λ , 4 ^{λ λ} , 4 '''as in turbine blades and turbine parts, this is preferably chromium.

By a heat treatment, which is usually carried out in the context of the production of a component, then finds a diffusion between the plug 7 ^λ , 7 ^{λ λ} , 7 ¹¹¹ and the substrate 4 ^λ , 4 ^{λ λ} , 4 '''instead, so that a chromium diffusion layer 10 \ 10 '10'"(FIG. 3) is formed.

Figure 2 shows another example in which the plug 7 ^{λ λ} for the component 1 ^{λ λ is} cylindrical.

In Figure 3, the plug 7 ^{λ λ} for the component 1 ^{λ λ λ has} a truncated cone shape. Both in FIG. 2 and in FIG. 3, between the plug 7 ^{λ λ} , 7 ^{Ν Ϊ Ϊ} and hole 8 ^{λ λ} , 8 ^{Ν Ϊ Ϊ there is} a diffusion layer 10 ^{λ λ} , 10.

The diffusion layer 10 ^λ , 10 ^{λ λ} , 10 ^{λ λ λ} can be generated in advance in the hole 8 8 ^{λ λ} , 8 ^{Ν Ϊ Ϊ} and / or on the plug 1 7 ^{λ λ} , 7 ^{Ν Ϊ Ϊ} and then brought together.

Likewise, before the heat treatment, diffusion material for producing this diffusion layer 10 ^λ , 10 ^{λ λ} , 10 ^{λ λ λ} on the surfaces of the hole 8 8 ^{λ λ} , 8 ^{Ν Ϊ Ϊ} in the substrate 4 ^λ , 4 ^{λ λ} , 4 ^{Ν Ϊ Ϊ} and / or the plug 7 ^λ , 7 ^{λ λ} , 7 '''are applied. Only then are the plugs 7 ^λ , 7 ^{λ λ} , 7 ^{Ν Ϊ Ϊ} in the hole 8 ^λ , 8 ^{λ λ} , 8 'introduced.

Claims

claims

1st component (1 1 ^{λ λ} , 1 ^{λ λ λ} )

with a substrate (4 ^λ , 4 ^{λ λ} , 4 ^{λ λ λ} ),

which has a hole (8 ^λ , 8 ", 8 ^{λ λ λ} ),

in which there is a plug (7 ^λ , 7 ^{λ λ} , 7 ^{λ λ λ} ),

to close the hole (8 ^λ , 8 ", 8 ^{λ λ λ} ),

wherein on the plug (7 7 ^{λ λ} , 7 ^{λ λ λ} )

and / or in the hole (8 8 ^{λ λ} , 8 ^{λ λ λ} ) on the substrate (4 ^λ , 4 ^{λ λ} , 4 ^{λ λ λ} )

between the plug (7 ^λ , 7 ^{λ λ} , 7 ^{λ λ λ} ) and substrate (4 ^λ , 4 ^{λ λ} , 4 ^{λ λ λ} ) a diffusion layer (10 ⁴ , 10 10 ^{λ λ λ λ} ) is present.

2. Component according to claim 1,

in which the plug (7 ^λ ) is arranged by means of a thread in the substrate (4).

3. Component according to claim 1,

 wherein the plug (7 ") has a cylindrical shape.

4. Component according to claim 1,

wherein the plug (7 ^{λ λ λ} ) has a truncated cone shape.

5. Component according to one or more of claims 1, 2, 3 or 4,

wherein the substrate (4 ^λ , 4 ^{λ λ} , 4 ^{λ λ λ} ) comprises a nickel- or cobalt-based superalloy.

6. Component according to one or more of claims 1, 2, 3, 4 or 5,

wherein the diffusion layer (10 10 ^{λ λ} , 10 ^{λ λ λ} ) a

Represents chromium diffusion layer.

7. Component according to one or more of claims 1, 2, 3, 4, 5 or 6,

in which the material of the plug (7 ^λ , 7 ^{λ λ} , 7 ^{λ λ λ} ) corresponds to the material of the substrate (4 ^λ , 4 ^{λ λ} , 4 ^{λ λ λ} ) or is artverwandt.

8. Procedure

 for producing a secure closure of a hole (8 \ 8 '8 in a substrate (4 \ 4' 4 '"),

in which at least in the hole (8 ^λ , 8 ", 8 ^{λ λ λ} ) of the substrate (4 ^λ , 4 ^{λ λ} , 4 ^{λ λ λ} ) and / or on the plug (7 7 ^{λ λ} , 7 ^{λ λ λ} ) one Diffusion layer (10 10 ^{λ λ} , 10 ^{λ λ λ} ) is applied and

 the stopper (7 \ Ί 'Ί' ") into the hole (8 \ 8 '8

 is introduced,

 and a heat treatment,

in particular, a heat treatment due to a necessary material treatment of the substrate (4 ^λ , 4 ^{λ λ} , 4 ^{λ λ λ} ), with substrate (4) and the introduced there plug (7 ^λ , 7 ^{λ λ} , 7 ⁴⁴ ,

 is carried out,

and in which a diffusion layer (10 10 ^{λ λ} , 10 ^{λ λ λ} ) is formed between and in the plug (7 ^λ , 7 ^{λ λ} , 7 ^{λ λ λ} ) and the substrate (4 \ 4 '4'").

9. The method according to claim 8,

in which only the plug (7 ^λ , 7 ^{λ λ} , 7 ^{λ λ λ} ) beforehand obtains a diffusion layer (10 10 ^{λ λ} , 10 ^{λ λ λ} ) and then into the hole (8 8 ^{λ λ} , 8 ^{λ λ λ} ) is introduced.

10. The method according to claim 8,

in which only the substrate (4 ^λ, 4 ^{λ λ,} 4 ^{λ λ λ)} receives in advance a diffusion layer (10 10 ^{λ λ,} 10 ^{λ λ λ),} and then the plug (7 7 ¹ 7 ^{λ λ λ)} in the hole ( 8 \ 8 ^{1 1} , 8 ^{1 1 1} ) is introduced.

11. The method according to claim 8,

in which the plug (7 7 ^{λ λ} , 7 ^{λ λ λ} ) and the substrate (4 ^λ , 4 ^{λ λ} , 4 ^{λ λ λ} ) obtained in advance a diffusion layer (10 10 ^{λ λ} , 10 ^{λ λ λ} ) and then in the Hole (8 ^λ , 8 ^{λ λ} , 8 ^{λ λ λ} ) are brought together.

12. The method according to claim 8,

in which a diffusion material for producing a diffusion layer (10 10 ", 10 ¹ ) on the plug (7 \

7 ^{λ λ λ} ) and / or in the hole (8 8 ^{λ λ} , 8 ^{λ λ λ} ) is applied.

13. The method according to claim 8,

in which a diffusion material for producing a diffusion layer (10 10 ", 10 ¹ ) on the plug (7 \

7 ^{λ λ λ} ) and in the hole (8 ^λ , 8 ^{λ λ} , 8 ^{λ λ λ} ) is applied, and then the plug (7 ^λ , 7 ^{λ λ} , 7 ^{λ λ λ} ) in the hole (8 8 ^{λ λ} , 8 ^{λ λ λ} ) is introduced.

14. The method according to claim 8,

in which a diffusion material for producing a diffusion layer (10 10 '10 ¹ ) is applied only to the plug (7 \ 7 ^{λ λ λ} ),

and then the plug (7 ^λ , Τ ', 7 ^{λ λ λ} ) in the hole (8 8 ", 8 ^{λ λ λ} ) is introduced.

15. The method according to claim 8,

in which a diffusion material for producing a diffusion layer (10 10 '10 ¹ ) is applied only in the hole (8 8'', 8 ^{λ λ λ} ),

 and then the plug (7 \ Ί '") into the hole (8 \ 8",

8 ^{λ λ λ} ) is introduced.

16. The method according to one or more of claims 8 to 15,

in which the diffusion material or the diffusion layer (10 10 ^{λ λ} , 10 ^{λ λ λ} ) contains chromium (Cr).