METHOD FOR MANUFACTURING A METAL REINFORCEMENT FOR A TURBOMACHINE BLADE

Abstract

The invention relates to a method for manufacturing a metal reinforcement (3) for a turbomachine blade, in particular an aircraft blade, the metal reinforcement (3) being intended to extend along an edge of the blade and comprising two lateral fins (32, 34) and a nose (36) connecting the two lateral fins (32, 34) together, the method comprising the steps of: (a) producing at least one intermediate preform (30) of the metal reinforcement (3) by additive manufacturing, the intermediate preform (30) having at least one excess thickness, and (c) forging the intermediate preform (30) so as to remove said at least one excess thickness. Figure for the abstract: Fig. 9

Description

Title of the invention: METHOD FOR MANUFACTURING A METAL REINFORCEMENT FOR A TURBO-MACHINE BLADE Field of invention

[0001] The present invention relates to a method for manufacturing a metal reinforcement for a turbomachine blade, in particular an aircraft blade. The present invention also relates to a metal reinforcement obtained by such a method, a turbomachine blade comprising this metal reinforcement and a turbomachine, in particular an aircraft blade, comprising such a blade. Technical background

[0002] It is known that a turbomachine, in particular an aircraft one, comprises blades each having an aerodynamic profile.

[0003] The blade comprises a lower surface and an upper surface connected to each other by a leading edge and a trailing edge. The leading edge corresponds to an upstream portion (in the direction of airflow in the turbomachine) which faces an airflow and divides the flow of the airflow into an upper surface airflow and an upper surface airflow. The trailing edge corresponds to the downstream portion of the aerodynamic profile where the lower surface and upper surface airflows meet.

[0004] Turbomachine blades, such as blades of a fan or a turbomachine rectifier, can undergo significant mechanical stresses linked in particular to the rotation speed, and must be able to satisfy strict conditions of weight and size. One of the options considered for lightening the blades is the use of composite materials for their manufacture.

[0005] It is known to equip turbomachine blades with a metal reinforcement extending along the leading edge of the blade. Such a metal reinforcement makes it possible to protect the blade during an impact from a foreign body (such as a bird, hail or even stones). In the case of blades made of composite material, the metal reinforcement also makes it possible to protect the leading edge by avoiding risks of delamination, breakage of fibers of the composite material or even damage by decohesion between the fibers and the matrix making up the composite material.

[0006] The metal reinforcement generally comprises two lateral fins connected to each other by a contiguous intermediate portion, called a nose.

[0007] The metal reinforcement is generally glued to the leading edge of the blade, for example over the entire height of the leading edge and a lengthwise portion of the intrados and extrados of the blade.

[0008] The metal reinforcement can be produced entirely by forging from a block of metal material (such as a bar or a thick sheet) by making several compression passes (for example between three and five passes).

[0009] [Fig.l] illustrates an example of production of the metal reinforcement 1 by forging which may comprise the following steps: (la) providing a metal bar 40 extending along a longitudinal axis A, (1b) carrying out several forging passes of the metal bar 40 to obtain a twisted metal bar 40 for example with a double camber according to first C and second B directions by means of a press, the second direction B is perpendicular to the axes A and C, (le) carrying out forging by spinning the twisted metal bar 40 from step (1b) so as to obtain an intermediate part 400 substantially U-shaped or V-shaped in cross-section to form the two lateral fins 32, 34 located on either side of a solid part 402 (intended to form the nose 36 of the metal reinforcement 3) and the pins 404 at the ends of the intermediate part 400 to allow handling, (Id) carrying out a shaping of the intermediate part 400 in a shaping tool having the final shape of the metal reinforcement 2, and (le) carry out a machining finishing step to remove in particular the pins 404 and polishing in order to obtain the required surface condition of the metal reinforcement 3. The metal reinforcement obtained according to the process of [Fig.l] requires at least approximately five forging passes with different tools for each pass.

[0010] With reference to [Fig.2], the metal reinforcement 3 can be produced by diffusion welding which can comprise the following steps: (2a) providing two metal sheets 50 having a flat shape, (2b) performing hot forming on each of the two metal sheets 50 to curve them, (2c) performing diffusion welding to assemble the two preformed metal sheets 500 together with another O-shaped tool so as to obtain the final shape of the metal reinforcement 3, and (2d) carry out a finishing and polishing step in order to obtain the required surface condition of the metal reinforcement 3.

[0011] However, the metal reinforcement is a complex part to produce, requiring numerous reworking operations and complex tools involving significant production costs. Furthermore, the aerodynamic profile (i.e. with a twisted three-dimensional geometry and a thickness that can vary between the nose and the side fins) can be complex to produce by forging or diffusion welding.

[0012] The metal reinforcement can be produced by additive manufacturing, such as powder bed additive manufacturing using a high-energy laser beam (LBM process, acronym for Laser Beam Melting). The LBM process makes it possible to selectively consolidate layers of powder in order to constitute, layer by layer, a three-dimensional part, such as the metal reinforcement.

[0013] However, additive manufacturing can generate a so-called degraded surface condition (or otherwise said to be granular, rough and non-smooth) of the metal reinforcement. [Fig. 3] illustrates an example of a surface condition of the metal reinforcement obtained by additive manufacturing which has so-called degraded zones ZD which are identified by arrows in this [Fig. 3]. This metal reinforcement generally has a surface roughness Ra of between 5 and 50 pm. This degraded surface condition does not make it possible to form an aerodynamic profile that is sufficiently smooth and suitable for use with the turbomachine blade.

[0014] Following the LBM process, the outer surface of the metal reinforcement can be treated, for example, by chemical polishing to reduce its degraded surface condition. [Fig. 4] illustrates an example of the surface condition of the metal reinforcement after a surface treatment by chemical polishing which still has degraded zones ZD. Thus, this surface treatment does not allow the roughness of the outer surface of the metal reinforcement to be sufficiently reduced. In addition, the surface treatment can be complex to implement on the metal reinforcement which has a changing thickness (in particular between the nose and the lateral fins).

[0015] In this context, the invention aims to solve the problems mentioned above, by proposing a method for producing a metal reinforcement for a turbomachine blade, in particular an aircraft blade, making it possible to simplify and optimize the manufacturing range of such a metal reinforcement, and to significantly reduce manufacturing costs. Summary of the invention

[0016] The invention provides a simple, effective and economical solution to the aforementioned drawbacks of the prior art.

[0017] To this end, the invention proposes a method for manufacturing a metal reinforcement for a turbomachine blade, in particular an aircraft blade, the metal reinforcement being intended to extend along an edge of the blade and comprising two lateral fins and a nose connecting the two lateral fins together, the method comprising the steps of: (a) production of at least one intermediate preform of the metal reinforcement by additive manufacturing, said intermediate preform having at least one excess thickness, and (c) forging said intermediate preform so as to remove said at least one excess thickness.

[0018] Thus, this solution makes it possible to achieve the aforementioned objective. In general, the method according to the invention makes it possible to simplify and optimize the production of the metal reinforcement. For this, the metal reinforcement is initially produced with an excess thickness by additive manufacturing, then this excess thickness is removed by forging.

[0019] Additive manufacturing makes it possible to form the metal reinforcement with the excess thickness in one piece, to maintain continuity of material between the lateral fins and the nose of the metal reinforcement, and to easily produce the twisted shape and evolving thickness of the metal reinforcement. The excess thickness makes it possible to reduce possible deformations due to the low thickness of the metal reinforcement which can occur during its handling, for example when cutting the parts from the manufacturing plate.

[0020] Forging (or otherwise known as forging) is the set of techniques used to obtain a mechanical part by plastic deformation, cold or hot, by applying a significant force to a piece of metal in order to force it to take on the desired shape. It is therefore understood that the force applied during forging makes it possible to eliminate the aforementioned excess thickness by constraining the material. Forging also makes it possible to carry out surface hardening of the material, which makes it possible to optimize the optimal mechanical properties of the metal reinforcement.

[0021] Advantageously, the forging step can be carried out in a single pass. This makes it possible to provide the part with these final properties (such as a surface condition, mechanical property and the removal of excess thickness).

[0022] More particularly, forging has the following advantages: - significantly improves the surface condition of the metal reinforcement (in particular with the smoothest possible, homogeneous and continuous surface so as to adapt to the aerodynamic profile of the blade), - reduce or eliminate all indications of porosity or lack of fusion from additive manufacturing (in particular, obtain a porosity rate of less than 0.1%), - improve the microstructure of the metal reinforcement, - improve the impact resistance of the metal reinforcement, - re-conform the metal reinforcement with the desired final dimensions, and - obtain the final dimensioning according to a predetermined tolerance of the metal reinforcement.

[0023] The method according to the invention can also facilitate the mass production of the metal reinforcement (for example at least one series of between two and ten or more than ten).

[0024] Furthermore, the use of a more efficient process for producing the reinforcement The metal reinforcement according to the invention is also advantageous for reducing the environmental footprint. Indeed, it makes it possible to increase and optimize manufacturing, production and / or repair capacity and, consequently, to significantly reduce the associated greenhouse gas emissions. This optimization also makes it possible to extend the service life of the metal reinforcement and, consequently, to reduce the number of replacements of new parts, and to significantly reduce the number of discarded parts which may be difficult to recycle.

[0025] The manufacturing method according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another:

[0026] - said at least one excess thickness is located over the entire inter preform mediator;

[0027] - the method comprises, between steps (a) and (c), a processing step (b) thermal of at least a portion of the intermediate preform;

[0028] step (b) of heat treatment is carried out at a temperature between 700°C and 800°C, for example approximately 730°C, and with a duration between 100 and 150 minutes, for example approximately 120 minutes;

[0029] - said excess thickness is between 0.2 and 1 mm, for example between 0.2 and 0.5 mm ;

[0030] - the intermediate preform in step (a) has a surface roughness Raa minimum of about 3 pm, for example between 3 and 50 pm;

[0031] - the metal reinforcement in step (c) has a surface roughness Rac less than 1.6 pm, for example between 0.6 and 1.6 pm;

[0032] the additive manufacturing of step (a) is carried out by laser powder bed fusion (LBM), laser powder deposition by laser fusion (LDM), fused filament deposition (FFF), extrusion (EAM), pellet extrusion (FGF) or injection of a binder onto a powder bed;

[0033] - the forging of step (c) is carried out by die-stamping the inter preform under pressure mediator;

[0034] - the method comprises, after step (c), a final step (d) of polishing the reinforcement metallic;

[0035] — the metal reinforcement is made of a metallic material, such as titanium, an alloy titanium-based (e.g. TA6V type), steel (e.g. stainless steel) or a nickel and cobalt alloy (NiCo);

[0036] — the metal reinforcement extending along a leading edge and / or a trailing edge of dawn.

[0037] The invention also relates to a metal reinforcement for a turbomachine blade, in particular an aircraft blade, obtained by a manufacturing method according to one of the particularities of the invention.

[0038] The metal reinforcement comprises at least one portion worked by forging. More particularly, the work-hardened portion is formed by removing the excess thickness by forging.

[0039] The metal reinforcement and in particular its work-hardened portion may have a surface roughness Rac of less than 1.6 pm, for example between 0.6 and 1.6 pm.

[0040] The invention also relates to a turbomachine blade, in particular an aircraft blade, comprising a metal reinforcement according to the invention. The blade comprises a lower surface and an upper surface connected to each other by a leading edge and a trailing edge of the blade, the metal reinforcement extending along the leading edge or the trailing edge.

[0041] The invention further relates to a turbomachine, in particular for an aircraft, comprising at least one blade according to the invention. Brief description of the figures

[0042] The invention will be better understood and other details, characteristics and advantages of the invention will appear more clearly on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

[0043] [Fig.l] schematically represents a first example of a method for manufacturing a metal reinforcement according to the prior art,

[0044] [Fig.2] schematically represents a second example of a method of manufacturing a metal reinforcement according to the prior art,

[0045] [Fig.3] represents a surface state of a metal reinforcement obtained by LBM type additive manufacturing according to the prior art,

[0046] [Fig.4] represents a surface state after surface treatment of the metal reinforcement of [Fig.3],

[0047] [Fig.5] is a half axial sectional view schematically representing an aircraft turbomachine,

[0048] [Fig.6] is a schematic profile view of a rotor-type blade of an aircraft turbomachine comprising a metal reinforcement according to the invention,

[0049] [Fig.7] is a schematic profile view of a stator-type blade of an aircraft turbomachine comprising a metal reinforcement according to the invention,

[0050] [Fig.8] is a partial schematic sectional view of [Fig.6] or 7 along section plane BB,

[0051] [Fig.9] schematically represents a method of manufacturing the metal reinforcement according to the invention,

[0052] [Fig. 10] is a schematic axial sectional view of the intermediate preform of the metal reinforcement with an excess thickness according to a first embodiment,

[0053] [Fig.l 1] is a schematic axial sectional view of the intermediate preform of the metal reinforcement with an excess thickness according to a second embodiment.

[0054] Elements having the same functions in different implementations have the same references in the figures. Detailed description of the invention

[0055] By convention, in the description below, the terms "longitudinal" and "axial" qualify the orientation of structural elements extending in the direction of a longitudinal axis (such as that of a turbomachine). The terms "radial" or "vertical" qualify an orientation of structural elements extending in a direction perpendicular to the longitudinal axis. The terms "inner" and "outer", and "internal" and "external" are used with reference to a positioning relative to the longitudinal axis. Thus, a structural element extending along the longitudinal axis has an inner face facing the longitudinal axis and an outer surface, opposite its inner surface.

[0056] Figures 1 to 4 have been described in the technical background of the present application and illustrate examples of manufacturing a metal reinforcement according to the prior art and its surface condition.

[0057] The invention can be applied in a non-limiting manner to a turbomachine 10, in particular an aircraft turbomachine.

[0058] The turbomachine 10 may be shrouded, which is for example shown in [Fig.5]. The turbomachine 10 may be a turbojet, turboshaft or turboprop.

[0059] The turbomachine 10 extends around a longitudinal axis X. It comprises from upstream to downstream in the direction of flow of the gases F along the longitudinal axis X, a fan 2a, at least one compressor (such as a low-pressure compressor 1a and / or a high-pressure compressor 1b), a combustion chamber 1c, at least one turbine 1d (such as a high-pressure turbine and / or a low-pressure turbine) and a nozzle (not shown).

[0060] The turbomachine 10 further comprises a rectifier 2b. The rectifier 2a may comprise at least one annular row of blades 2 (in particular fixed ones), called OGV blades extending around the axis X. The OGV blades make it possible to straighten the flow at the outlet of a rotor located upstream in order to provide maximum thrust at the outlet of the turbomachine 10. In the particular example of [Fig.l], the rectifier 2b is located downstream of the fan 2a and makes it possible to straighten a secondary flow F2.

[0061] The fan 2a comprises an annular row of blades 2 (in particular mobile blades), called fan blades extending around the axis X. The fan 2a allows the suction of an air flow dividing into a primary flow F1 and a secondary flow F2. The primary flow F1 passes through a primary vein of the turbomachine 10 while the secondary flow F2 is directed towards a secondary vein surrounding the primary vein.

[0062] The primary flow Fl is compressed within the low pressure compressor la then high-pressure compressor 1b. The compressed air is then mixed with fuel and burned in the combustion chamber 1c. The gases formed by the combustion pass through the turbine 1d. The gases finally escape through the nozzle, the cross-section of which allows the acceleration of these gases to generate propulsion. The secondary flow F2 passes through the rectifier 2b, which accelerates the circulation speed of the secondary flow F2 to generate propulsion.

[0063] The fan 2a, the low-pressure compressor 1a, the high-pressure compressor 1b, the turbine 1d (high pressure and / or low pressure), and the rectifier 2a each comprise blades 2. The blades 2 may be movable (for example the fan blade of [Fig.6]) in rotation about the longitudinal axis X, or fixed (the blade 2 OGV of the rectifier 2b of [Fig.7]) relative to the axis X. The blades 2 extend radially relative to the axis X.

[0064] In the following description, the invention will be described in the context of its application in a non-limiting manner to the blade 2 with reference to FIGS. 5 to 8. This blade 2 can be mobile from the fan 2a ([Fig.6]) or fixed from the rectifier 2b ([Fig.7]).

[0065] The invention is however not limited to a moving fan or rectifier blade of a shrouded turbomachine, and can be applied generally to other types of blades, such as: - fixed and / or moving blades of the low pressure 1a and high pressure 1b compressors, of the high pressure and low pressure turbines of the turbomachine 10, and / or - fixed and / or moving blades of an unducted turbomachine.

[0066] With reference to Figures 6 and 7, the blade 2 extends, on the one hand, along an elongation axis A (substantially vertical in Figures 5 and 7), and on the other hand, along a longitudinal axis B (substantially horizontal in Figures 6 and 7). This axis A is substantially perpendicular to the axis B. The axis A is substantially perpendicular or inclined to the axis X of the turbomachine 10.

[0067] The blade 2 may comprise a lower surface face 21 (hereinafter referred to as the lower surface) and an upper surface face 22 (hereinafter referred to as the upper surface). The lower surface 21 and the upper surface 22 extend transversely between a leading edge 23 and a trailing edge 24 of the blade 2.

[0068] The blade 2 may comprise a vane 20. In the present application, the vane 20 may be likened to the blade 2.

[0069] The blade 20 may have an aerodynamic profile to form the aerodynamic part of the blade 2. For this, the blade 20 may have a curved profile of variable thickness between the leading edge 23 and its trailing edge 24 of the blade 2.

[0070] In the examples of figures 6 and 7, the blade 20 extends along the axis A between a first end and a second end opposite the first end.

[0071] In the case of the moving blades 2 of [Fig.6], these blades 2 may comprise each furthermore a foot 26. The foot 26 is in particular connected to the second end of the blade 20. It is intended to be fixed to a disk (not shown) for example mobile in rotation around the axis X. The second end is free and configured to form a tip 25 (or a head) of blade 2.

[0072] In the case of the fixed blades 2 of the shrouded turbomachine of [Fig.7], these blades 2 may each further comprise a first platform 27a and a second opposite platform 27b. The first platform 27a is integral with the first end of the blade 20 and the second platform 27b is integral with the second end.

[0073] As a variant (not shown), of the fixed blades of an unducted turbomachine, the second end of these blades comprises the second platform 27b and the first end is free.

[0074] The blade 2 can be made of composite material. Preferably, the blade 2 can be formed by a fiber preform embedded in a resin (organic matrix composite material).

[0075] Furthermore, the blade 2 may also comprise a metal reinforcement 3 (or in other words a metal shield, a metal foil). This metal reinforcement makes it possible to protect the blade against external impacts (gravel from a takeoff / landing runway, hailstones, birds, etc.) and against erosion of the blade or delamination of the blade.

[0076] The metal reinforcement 3 can extend along the leading edge 23 and / or the trailing edge 24 of the blade 2. Advantageously, the metal reinforcement 3 can extend in height (relative to the axis A) and over a portion in length (relative to the axis B) of the intrados 21 and the extrados 22 from the leading edge 23 or the trailing edge 24.

[0077] The metal reinforcement 3 can be fixed to the leading edge 23 and / or to the trailing edge 24 by gluing.

[0078] With reference to [Fig.8], the metal reinforcement 3 may have a general shape, in cross section relative to the axis A, in a “V” or “U”. The metal reinforcement 3 may comprise two lateral fins, respectively, intrados 32 and extrados 34. The intrados lateral fin 32 is connected to the extrados lateral fin 34 by an intermediate portion called a “nose” 36. The lateral fins 32, 34 and the nose 36 are monobloc (i.e. made in one piece).

[0079] The side fins 32, 34 and the nose 34 may define between them a cavity in which the leading edge 23 or the trailing edge 24 is arranged. The side fins 32, 34 may be tapered in the opposite direction to the nose 36.

[0080] The metallic material of the metallic reinforcement 3 may be titanium, a titanium-based alloy (for example TA6V type), a steel (for example stainless steel) or a nickel and cobalt alloy (NiCo).

[0081] One of the particularities of the invention is that the metal reinforcement 3 can comprise at least one work-hardened or forged portion.

[0082] The metal reinforcement 3 may have a surface roughness Rac of less than 1.6 pm, for example between 0.6 and 1.6 pm.

[0083] The present application will now describe a method of manufacturing the metal reinforcement 3 as described below (in particular with reference to FIGS. 5 to 8).

[0084] Figures 9 to 11 illustrate in a non-limiting manner at least one of the steps of the method of the invention.

[0085] Generally speaking, the method according to the invention comprises the steps of: (a) production of at least one intermediate preform 30 of the metal reinforcement 3 by additive manufacturing, this intermediate preform 30 having at least one excess thickness 300, and (c) forging the intermediate preform 30 so as to remove the at least one excess thickness 300.

[0086] In step (a), the excess thickness 300 may be located over the entirety of the intermediate preform 30. [Fig. 10] illustrates in a non-limiting manner the excess thickness 300 formed over the entirety of an internal surface of the intermediate preform 30. As a variant, this excess thickness 300 may extend over the entirety of an external surface of the intermediate preform 30.

[0087] [Fig. 11] illustrates another example of the intermediate preform 30 in which the excess thickness 300 is located only on the lateral fins 32, 34 (in particular on the external surface of the lateral fins), thus the excess thickness 300 is not present on the nose 36. In a variant not illustrated, the excess thickness 300 may be located only on the nose 36 and absent from at least one of the lateral fins 32, 34.

[0088] The excess thickness 300 may be between 0.2 and 1 mm. For example, the excess thickness may be between 0.2 and 0.5 mm. This makes it possible to carry out the forging to obtain the metal reinforcement 3 with the desired final dimensions and mechanical properties. In addition, this excess thickness makes it easier to handle the intermediate preform 30 without deforming it, for example when cutting the intermediate preform 30 from a manufacturing plate (visible in [Fig.9]).

[0089] The dimension and position of the excess thickness 300 on the metal reinforcement 3 can be variable depending on the manufacturing parameters and / or the final shape desired for the metal reinforcement 3.

[0090] In [Fig.9], step (a) illustrates in a non-limiting manner the production of several intermediate preforms 30 joined by additive manufacturing on a manufacturing plate P. Before carrying out step (c), and possibly before step (b), the method may comprise a step of cutting the intermediate preforms 30 to separate them from each other and from the plate P.

[0091] In step (a), additive manufacturing can be carried out by laser powder bed fusion (LBM), laser direct manufacturing (LDM), fused filament fabrication (FFF), extrusion (EAM), extrusion of granules (FGF) or injection of a binder onto a powder bed (also known as binder jetting).

[0092] Additive manufacturing makes it possible to produce parts with complex shapes, such as a U or V shape in cross section and the evolving thickness of the metal reinforcement 3.

[0093] LBM additive manufacturing makes it possible to selectively consolidate layers of powder in order to constitute, layer by layer, the metallic reinforcement 3 with the excess thickness 300 in three dimensions.

[0094] FFF additive manufacturing allows successive layers of materials to be deposited using a filament of molten polymer material or a resin filament.

[0095] EAM additive manufacturing makes it possible to deposit a continuous filament of composite or thermoplastic material to build the metal reinforcement 3 layer by layer with the excess thickness 300 in three dimensions.

[0096] FGF additive manufacturing makes it possible to deposit granules of melted composite or thermoplastic material layer by layer to form the metal reinforcement 3 with the excess thickness 300 in three dimensions.

[0097] The intermediate preform 30 in step (a) may have a minimum surface roughness Raa of approximately 3 μm. For example, this roughness Raa may be between 3 and 50 μm. The surface condition of the intermediate preform 30 may substantially correspond to that illustrated in [Fig. 3].

[0098] In step (c), the forging thus makes it possible to form the work-hardened portion of the metal reinforcement 3. Furthermore, the forging also makes it possible to reduce the intermediate preform 30 to a single forging pass to form the metal reinforcement 3.

[0099] The metal reinforcement 3 at this step (c) may have a surface roughness Rac of less than 1.6 pm. This roughness Rac may be more particularly between 0.6 and 1.6 pm. This makes it possible to form a sufficiently smooth, homogeneous and continuous surface so as to adapt to the aerodynamic profile of the blade.

[0100] In step (c), the forging (or in other words the work hardening) can be carried out by die-forging under a press of the intermediate preform 30, in particular of the excess thickness 300. For example, the intermediate preform 30 can be deformed (or in other words work hardened) by forging with a press, for example an isothermal press brought to a temperature between 700°C and 940°C to have good deformation properties. formation of titanium in particular at low forging speed. According to another variant, the forging of step (c) can be carried out using a screw press and a punch / die tool.

[0101] Forging makes it possible in particular to twist and give the final or quasi-final shape of the metal reinforcement 3.

[0102] Advantageously, the forging step can be carried out in a single pass. This makes it possible to provide the part with these final properties (such as a surface condition, mechanical property and the removal of excess thickness).

[0103] In the event of material burr after forging, step (c) may include a step of machining this burr.

[0104] The method of the invention may comprise, between steps (a) and (c), a step (b) of heat treatment of at least a portion of the intermediate preform 30. This makes it possible to reduce or even eliminate the residual stresses and thus limit the deformations of the intermediate preform 30 at the end of the additive manufacturing step (a).

[0105] This heat treatment step (b) can be carried out at a temperature of between 700°C and 800°C and with a duration of between 100 and 150 minutes. For example, step (b) can be carried out at a temperature of approximately 730°C (with a possible temperature variation of approximately + / - 10°C) for approximately 120 minutes (with a possible variation in duration of approximately + / - 10%).

[0106] The method of the invention may comprise, after step (c), a final step (d) of polishing the metal reinforcement (3). This makes it possible to obtain the final shape and dimensions of the metal reinforcement 3 which is ready to be installed on the blade 2.

[0107] Furthermore, the method according to the invention can facilitate the mass production of the metal reinforcements 3 (for example at least one series of between two and ten or more than ten). For this, the intermediate preforms 30 can be formed in step (a) in a manner linked to each other to form the desired series of metal reinforcements. As an example, [Fig.9] illustrates approximately five intermediate preforms 30 formed in a single step (a). Then, the method can comprise a cutting step to form individual pieces of the intermediate preforms 30 (and consequently of the metal reinforcements 3). Each of these individual intermediate preforms 30 can be forged in step (c), and / or heat-treated in step (b), and / or polished in step (d). This cutting step can be carried out after the additive manufacturing step (a) or after the forging step (c).

Claims

Claims

1. Method for manufacturing a metal reinforcement (3) for a blade (2) of a turbomachine, in particular an aircraft, the metal reinforcement (3) being intended to extend along an edge (23, 24) of the blade (2) and comprising two lateral fins (32, 34) and a nose (36) connecting the two lateral fins (32, 34) together, the method comprising the steps of: (a) producing at least one intermediate preform (30) of the metal reinforcement (3) by additive manufacturing, said intermediate preform (30) having at least one excess thickness (300), and (c) forging said intermediate preform (30) so as to remove said at least one excess thickness (300).

2. Manufacturing method according to claim 1, characterized in that said at least one excess thickness (300) is located over the entire intermediate preform (30).

3. Manufacturing method according to any one of the preceding claims, characterized in that it comprises, between steps (a) and (c), a step (b) of heat treatment of at least a part of the intermediate preform (30).

4. Manufacturing method according to claim 3, characterized in that the heat treatment step (b) is carried out at a temperature between 700°C and 800°C, for example approximately 730°C, and with a duration between 100 and 150 minutes, for example approximately 120 minutes.

5. Manufacturing method according to any one of the preceding claims, characterized in that said excess thickness is between 0.2 and 1 mm, for example between 0.2 and 0.5 mm.

6. Manufacturing method according to any one of the preceding claims, characterized in that the intermediate preform (30) in step (a) has a minimum surface roughness Raa of approximately 3 pm, for example between 3 and 50 pm.

7. Manufacturing method according to any one of the preceding claims, characterized in that the metal reinforcement (3) in step (c) has a surface roughness Rac of less than 1.6 pm, for example between 0.6 and 1.6 pm.

8. Manufacturing method according to any one of the preceding claims, characterized in that the additive manufacturing of step (a) is performed by laser powder bed fusion (LBM), laser powder deposition by fusion (LDM), fused wire deposition (FFF), extrusion (EAM), pellet extrusion (FGF) or injection of a binder onto a powder bed.

9. Manufacturing method according to any one of the preceding claims, characterized in that the forging of step (c) is carried out by die-stamping the intermediate preform (30) under pressure.

10. Manufacturing method according to any one of the preceding claims, characterized in that it comprises, after step (c), a final step (d) of polishing the metal reinforcement (3).

11. Metal reinforcement (3) for a blade (2) of a turbomachine, in particular an aircraft, obtained by a manufacturing method according to any one of the preceding claims, and characterized in that the metal reinforcement comprises at least one portion hardened by forging.

12. Metal reinforcement according to the preceding claim, characterized in that said work-hardened portion has a surface roughness Rac of less than 1.6 pm, for example between 0.6 and 1.6 pm.

13. Blade (2) of a turbomachine, in particular of an aircraft, comprising a metal reinforcement (3) according to claim 11 or 12, the blade (2) comprising a lower surface (21) and an upper surface (22) connected to each other by a leading edge (23) and a trailing edge (24) of the blade, the metal reinforcement (3) extending along the leading edge (23) or the trailing edge (24).

14. Turbomachine (10), in particular for an aircraft, comprising at least one blade (2) according to claim 13.

Images