Armor and shovel tip

Abstract

The invention relates to an armor plating (10) for a blade tip (4) of a turbine blade (1), which comprises a matrix of NiCoCrAlY and hard material particles, preferably of cubic boron nitride (cBN), zirconium carbonate (ZrC) and / or aluminum oxide (Al2O3).

Description

[0001] The invention relates to an armor plating that can be used for a blade tip of a shovel.

[0002] Rubbing processes of turbine blades on stators such as guide ring segments lead to leakage losses in the turbine stages and to increased material wear on both components.

[0003] By coating a blade tip with cubic boron nitride (cBN) in a matrix of a superalloy corresponding to nickel-based superalloys of turbine blades, initial 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.

[0004] It is therefore an object of the invention to improve the longevity of such a blade tip.

[0005] The object is achieved by an armor plating according to claim 1 and a blade tip or turbine blade according to claim 5.

[0006] The subclaims list further advantageous measures which can be combined with each other as desired to achieve further advantages.

[0007] It shows Fig. 1 a turbine blade, Fig. 2, Fig. 3 armor, Fig. 4, Fig. 5 manufacturing steps of a blade tip with armor plating.

[0008] The figures and the description represent only embodiments of the invention.

[0009] Fig. 1 shows, by way of example, a turbine blade 1 which, in the lower region, has a blade root 2 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.

[0010] The blade tip 4 has an end 7 which defines a plane 9.

[0011] 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”).

[0012] The blade tip 4 has 7 armor platings 10 at its end.

[0013] Fig. 2 shows an example of an armor plating 10 used for the blade tip 4.

[0014] It is preferably cuboid or block-shaped.

[0015] The armor 10 is preferably manufactured using powder metallurgy.

[0016] Other manufacturing methods are possible, such as 3D printing or other additive processes.

[0017] The armor 10 has a metallic matrix based on (NiCo)CrAlY, also called MCrAlY.

[0018] 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.

[0019] The armor 10 contains at least 5 vol%, in particular at least 10 vol%, of hard material particles made of cubic boron nitride (cBN), zirconium carbonate (ZrC), and / or aluminum oxide (Al2O3). A maximum of 60 vol% of hard material particles, in particular a maximum of 50 vol%, is used.

[0020] Likewise, a maximum of 40vol% hard material particles are preferably used.

[0021] 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.

[0022] The shape of the armor 10 is shown here only schematically as a cuboid or block, but can or is preferably formed according to the curvature of the blade 3 or the wall 8 at the blade tip 4 (curved cuboid).

[0023] The contact surface 15 of the armor 10 can also be pointed, conical or wedge-shaped.

[0024] The armor preferably has a porosity of no more than 10vol%, in particular of no more than 5vol%.

[0025] Fig. 3 shows a variant of an armour 10' in which depressions or notches 13 are present on one, in particular on several or all side surfaces 11.

[0026] The recesses 13 preferably do not extend beyond the plane of the outer side surfaces 11 of the armor 10'.

[0027] In the installed state, the recesses 13 are preferably arranged below the level 9, ie completely in an inlet 23 ( Fig. 4) arranged.

[0028] Fig. 4 shows an armouring 10, 10' in the wall 8 or at the end 7 of the blade tip 4, wherein the armouring 10, 10' is preferably inserted into an inlet 23 in a form-fitting manner, but does not have to be ( Fig. 5).

[0029] 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.

[0030] The remelting can be carried out by a laser 16 ( Fig. 5) or other welding equipment or heat treatments.

[0031] It is also possible to apply additional material between the armor 10, 10' and the blade tip 4 using known welding filler materials or solder materials in order to fasten the armor 10 in the blade tip 4 or on the blade tip 4.

[0032] Preferably, a laser and / or powdered filler material is used.

[0033] The armor 10, 10' can protrude from the level 9 or from the wall 8, but can also be flush.

[0034] Preferably, eight to twelve such armorings 10 are applied on the suction and pressure sides of the turbine blade 1.

[0035] 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.

[0036] The armor 10 or in particular the upper surfaces of the armor 10 can be masked.

[0037] 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

[1] Armor (10) for a blade tip (4) of a turbine blade (1), wherein the armouring (10) is cuboid-shaped or block-shaped, wherein the armor (10) has a matrix of NiCoCrAlY or CoNiCrAlY and Hard material particles, which preferably comprise or consist of cubic boron nitride (cBN), zirconium carbonate (ZrC) and / or aluminum oxide (Al2O3). [2] Armour (10) according to claim 1, in which the hard material particles have a proportion of at least 5vol%, in particular at least 10vol%, have. [3] Armour (10) according to claim 1 or 2, in which the hard material particles have a maximum proportion of 60vol%, in particular a maximum of 50vol%, especially 40vol% have. [4] Armour (10) according to one or more of claims 1, 2 or 3, where the armor has a maximum porosity of 10vol%, especially 5vol%, has. [5] Blade tip (4) of a turbine blade (1) or turbine blade (1) having an armor (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 armour (10, 10') is arranged. [7] Blade tip according to claim 5 or 6, in which the armor (10, 10') is connected to the blade tip (4) by remelting. [8] Blade tip according to claim 5 or 6, in which the armor (10, 10') is welded or soldered using filler material connected to the blade tip (4). [9] 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 has a plurality of armorings (10, 10') on the suction and / or pressure side of the turbine blade (1). [12] Blade tip according to claim 11, which has 8 to 12 armorings (10, 10') on the suction and pressure sides of the turbine blade (1).

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