Hard face coating and blade tip

Abstract

The invention relates to a hard face coating (10) for a blade tip (4) of a turbine blade (1), the coating comprising a matrix of NiCoCrAlY and hard material particles, preferably consisting of cubic boron nitride (cBN), zirconium carbonate (ZrC) and / or aluminum oxide (Al2O3).

Description

[0001] Armor and shovel tip

[0002] The invention relates to an armor plating that can be used for a blade tip of a shovel.

[0003] Rubbing of turbine blades on stators such as guide ring segments leads to leakage losses in the turbine stages and to increased material wear on both components.

[0004] By coating a blade tip with cubic boron nitride (cBN) in a matrix of a superalloy corresponding to nickel-based superalloys of the turbine blades, the first good results for the hardfacing of blade tips with the aim of separating them into abrasive coated guide ring segments could be achieved by means of build-up welding.

[0005] It is therefore an object of the invention to improve the longevity of such a blade tip.

[0006] The object is achieved by an armor plating according to claim 1 and a blade tip or turbine blade according to claim 5.

[0007] The subclaims list further advantageous measures which can be combined as desired to achieve further advantages.

[0008] It shows

[0009] Figure 1 a turbine blade,

[0010] Figure 2 , 3 an armor,

[0011] Figures 4 and 5 show manufacturing steps for a blade tip with armor plating. The figures and the description represent only exemplary embodiments of the invention.

[0012] Figure 1 shows an example of a turbine blade 1 which has a blade root 2 in the lower region for mounting in a turbine disk (the invention is also applicable to "bliscs") and an adjacent blade platform 5, from which a blade airfoil 3 extends in the longitudinal direction, at the end of which a blade tip 4 is provided.

[0013] The blade tip 4 has an end 7 which defines a plane 9 .

[0014] On the end 7 or the plane 9, a circumferential wall 8 can also extend in the longitudinal direction, which runs along the edge of the blade 3, so that a depression is present at the blade tip 4 (“squealer tip”).

[0015] The blade tip 4 has 7 armor platings 10 at its end .

[0016] Figure 2 shows an example of an armor plating 10 which is used for the blade tip 4 .

[0017] It is preferably cuboid or block-shaped.

[0018] The armor 10 is preferably manufactured using powder metallurgy.

[0019] Other manufacturing methods are possible, such as 3D printing or other additive processes.

[0020] The armor 10 has a metallic matrix based on (NiCo) CrAlY, also called MCrAlY.

[0021] Preferably, nickel-based alloys such as NiCoCrAlY-Re, NiCoCrAlY-Ta, NiCoCrAlY-Si, NiCoCrAlY-Si-Fe or cobalt-based alloys based on (CoNi)CrAlY are used.

[0022] The armor 10 contains at least 5vol%, in particular at least 10vol% hard material particles of cubic boron nitride

[0023] (cBN) , zirconium carbonate (ZrC) and / or aluminum oxide (A12O3) .

[0024] A maximum of 60vol% hard material particles, in particular a maximum of 50vol% hard material particles, is used.

[0025] Likewise, a maximum of 40vol% hard material particles are preferably used.

[0026] Other hard material particles are possible; they simply need to be oxidation-resistant for use in a gas turbine. These hard material particles are not metallic, or at least not an MCrAlY alloy.

[0027] The shape of the armor 10 is shown here only schematically as a cuboid or block, can or is preferably formed according to the curvature of the blade 3 or the wall 8 at the blade tip 4 (curved cuboid).

[0028] The contact surface 15 of the armor 10 can also be pointed, conical or wedge-shaped.

[0029] The armor preferably has a porosity of no more than 10vol%, in particular of no more than 5vol%.

[0030] Figure 3 shows a variant of an armouring 10' in which depressions or notches 13 are present on one, in particular on several or all side surfaces 11.

[0031] The recesses 13 preferably do not extend beyond the plane of the outer side surfaces 11 of the armor 10'.

[0032] In the installed state, the recesses 13 are preferably arranged below the plane 9, i.e., completely within an inlet 23 (Fig. 4). Figure 4 shows a plating 10, 10' in the wall 8 or at the end 7 of the blade tip 4, wherein the plating 10, 10' is preferably recessed into an inlet 23 in a form-fitting manner, but this is not necessary (Fig. 5).

[0033] Thereafter, the armor 10 can be fixed in or on the blade tip 4, the wall 8 or the end 7 by simply remelting the surrounding substrate.

[0034] The remelting can be carried out by a laser 16 (Fig. 5) or other welding devices or heat treatments.

[0035] It is also possible to apply additional material between the armor 10, 10' and the blade tip 4 using known welding filler or solder materials in order to fasten the armor 10 in the blade tip 4 or on the blade tip 4.

[0036] Preferably, a laser and / or powdered filler material is used.

[0037] The armor 10, 10' can protrude from the level 9 or from the wall 8, but can also be flush.

[0038] Preferably, eight to twelve such armorings 10 are introduced on the suction and pressure sides of the turbine blade 1.

[0039] Preferably, the turbine blade 1 is then coated with a ceramic thermal barrier coating system comprising an alloy based on NiCoCrAlY and optionally at least one ceramic layer.

[0040] The armor plating 10, or in particular the upper surfaces of the armor plating 10, can be masked. In combination with oxidation-resistant MCrAlY materials, a type of drill bit with any desired hard material content can be manufactured using powder metallurgy. These drill bits or hard material plates (= armor plating) are welded or brazed onto the blade tip.

Claims

Patent claims 1. Armouring (10) for a blade tip (4) of a turbine blade (1), wherein the armouring (10) is cuboid-shaped or block-shaped, wherein the armouring (10) has a matrix of NiCoCrAlY or CoNiCrAlY and hard material particles, which preferably have or consist of cubic boron nitride (cBN), zirconium carbonate (ZrC) and / or aluminium oxide (AI2O3).

2. Armouring (10) according to claim 1, wherein the hard material particles have a proportion of at least 5 vol%, in particular at least 10 vol%.

3. Armouring (10) according to claim 1 or 2, in which the hard material particles have a proportion of maximum 60vol%, in particular maximum 50vol%, very particularly 40vol%.

4. Armour (10) according to one or more of claims 1, 2 or 3, wherein the armour has a porosity of at most 10vol%, in particular 5vol%.

5. Blade tip (4) of a turbine blade (1) or turbine blade (1) comprising an armor plating (10) according to one or more of claims 1, 2, 3 or 4.

6. Blade tip according to claim 5, which has an inlet (23) for the armor (10, 10'), within which (23) the armor (10, 10') is arranged.

7. Blade tip according to claim 5 or 6, wherein the armoring (10, 10') is connected to the blade tip (4) by remelting.

8. Blade tip according to claim 5 or 6, wherein the armoring (10, 10') is connected to the blade tip (4) by welding or soldering using additional material.

9. A blade tip according to one or more of claims 5, 7 or 8, wherein the armor (10, 10') is attached to the top of one end (7).

10. Blade tip according to one or more of claims 5, 6, 7 or 8, wherein the armoring (10, 10') is flush with a flat surface of a wall (8) or end (7).

11. Blade tip according to one or more of claims 5, 6, 7, 8, 9 or 10, which have several armorings (10, 10') on suction and / or pressure side of the turbine blade (1).

12. Blade tip according to claim 11, each having 8 to 12 armorings (10, 10') on suction and pressure side of the turbine blade (1).

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