Method for manufacturing blade disk of turbine engine having orbital friction welded blades

Abstract

The invention relates to a bladed disc (2) for a turbomachine, comprising a plurality of blades (4) joined to a stub (6) on the disc by rail friction welding at a radial joint height h between the blades and the stub, notably that the blade has a radial joint height h between the blades and the stub. The radial joint height h measured from the inter-blade surface (8) of the disk is greater than or equal to a radial height hSC of a critical threshold (SC) plus half the maximum thickness emax of the weld. The invention relates to a method for manufacturing a bladed disk, in which emax is determined by a geometric parameter z of a section of the blade and the stub at the junction, where z is the mean value of the mean radius zi sweeping the section at any point i of the periphery of the section.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for manufacturing a bladed disc for turbomachinery, more particularly to a method for manufacturing a bladed disc by friction welding of the blade tracks to a turbomachinery rotor disc. The present invention also relates to a turbomachinery bladed disc obtained by the method. BACKGROUND

[0002] Climate change is a major concern for many legislative and regulatory bodies worldwide. In fact, various carbon emission limits have already been, are being or will be adopted by states. In particular, stringent standards apply both to new aircraft and to already in service aircraft that need to implement technical solutions to comply with current regulations. Civil aviation has been mobilized for many years to contribute to the fight against climate change.

[0003] Technical research work has already very significantly improved the environmental performance of aircraft. The Applicant has considered influencing factors at all stages of design and development to obtain less energy-consuming, more environmentally friendly aeronautical components and products, the integration and use of which in civil aviation have a moderate environmental impact, with the aim of increasing the energy efficiency of aircraft.

[0004] The Applicant is therefore constantly striving to reduce the negative climatic impact of greenhouse gases by using methods, operating benign development and manufacturing processes and reducing greenhouse gas emissions to the lowest possible level, to reduce the environmental footprint of activities that emit greenhouse gases.

[0005] This ongoing research and development work focuses on the development of new generations of aircraft engines, the weight reduction of aircraft (in particular through the materials used and lighter on-board equipment), the use of electrical technologies to ensure propulsion, and, as a necessary complement to technological progress, aviation biofuels.

[0006] To this end, the present invention is the result of technical research aimed at significantly improving the performance of aircraft and, in this sense, contributes to reducing the environmental impact of aircraft.

[0007] In the present document, the invention relates to a method for friction welding tracks for manufacturing a bladed disc (commonly known as "blisk") or a bladed drum (commonly known as "blum") of a turbomachinery compressor.

[0008] Friction welding of tracks is a welding process in which the components to be joined are brought into contact under stress and welded by a circumferential movement, usually defined by an eccentricity, with a uniform tangential speed, thus generating friction and uniform heating at the welded joint between the two components.

[0009] It is also known to use linear friction welding, which is a welding process that generates the necessary heat by back and forth movement of the interface to be welded. However, orbital friction welding has several advantages over linear friction, for example, due to the circular friction movement, the relative movement between the two interfaces is continuous, which provides better thermal homogeneity. Unlike linear movement, in which the relative velocity of the two parts becomes zero at each half oscillation period. Furthermore, the cycle time of orbital welding is significantly lower than that of linear friction welding (about 2 minutes versus about 5 minutes, respectively).

[0010] The published patent document EP1495829A1 discloses a method for manufacturing a combined profiled blade and disc, wherein each blade has a stub that is linearly friction welded to the disc. This document proposes a stub design comprising a ratio of the widest part to the narrowest part of the stub, which is less than 2, in order to minimize the curvature of the stub.

[0011] However, the stub design proposed in this document has room for improvement, since it cannot be applied to orbital welding. Indeed, such a stub cannot obtain a perfect, contamination-free orbital welded joint.

[0012] The published patent document EP2535516A1 discloses a method of orbital friction welding of a blade to a turbine rotor, wherein, once material consumption is reached in the welding area between the blade and the disc, the orbital movement is stopped at a reference position and a forging force is applied on the blade against the rotor to form the weld.

[0013] However, the orbital welding process disclosed in this document has room for improvement. This can require better control of the position of the blade welding area relative to the rotor disc, in order to avoid structural defects, while ensuring that the material in the welding area is perfect. SUMMARY

[0014] TECHNICAL PROBLEM The present invention aims to solve at least one of the problems posed by the prior art. More particularly, the present invention aims to propose a solution that makes it possible to accurately determine the radial height of the orbital friction welded joint of a blade to a rotor disc stub.

[0015] TECHNICAL SOLUTION The present invention is the result of a technical research aimed at significantly improving the performance of aircraft, and in this sense contributes to reducing the environmental impact of aircraft. To this end, the present invention relates to a method of manufacturing a blade disc comprising a blade extending radially outwardly from a stub that is joined to the disc by orbital friction welding, said method comprising a step of determining a radial joining height h between the blade and the stub, wherein the radial joining height h is determined as the maximum thickness e of the weldmax The function of radial joint height h increases the maximum thickness e of the weld. max The larger the weld, the greater the maximum thickness e. max The geometric parameter z of the section at the junction of the blade and the short column is determined by the geometric parameter z, where z is the average radius z sweeping across the section at each point i around the perimeter of the section. i The average value, the maximum thickness e of the welded part. max The smaller the value, the smaller the geometric parameter z.

[0016] According to an advantageous embodiment of the invention, the maximum thickness e of the welded portion max It is also determined by at least one of the following parameters of rail friction welding: eccentricity, frequency, and forging pressure.

[0017] According to an advantageous embodiment of the invention, the maximum thickness e of the welded portion max It is also determined by at least one of the following parameters of rail friction welding: eccentricity, frequency, and forging pressure.

[0018] According to an advantageous embodiment of the invention, the material consumption rate is measured during parameter-set track friction welding, which is performed with the same parameters as the track friction welding of the blade.

[0019] Preferably, the material consumption rate is measured by data acquisition on the machine performing the track friction welding.

[0020] According to an advantageous embodiment of the invention, the material consumption rate is determined based on the following track friction welding parameters: eccentricity, frequency, and forging pressure.

[0021] According to an advantageous embodiment of the invention, the radial engagement height h measured from the inter-blade surface of the disk is greater than or equal to the radial height h of the critical threshold. SC The radial height plus the maximum thickness e of the welded portion max Half of the defined tolerance interval IT.

[0022] Advantageously, the critical threshold corresponds to the limit to which a crack induced in the blade does not propagate toward the disk. The radial height h of the critical threshold. SC Calculated by crack propagation or by taking into account the radial height h SC It is determined to be greater than or equal to twice the radius of the fillet at the connection between the short column and the surface between the blade.

[0023] The determined tolerance range IT corresponds to the region including the joint, which is the area where the joint can exist, especially when the blade and the disk each include alloys different from the base material.

[0024] According to an advantageous embodiment of the application, the tolerance interval IT is greater than or equal to the maximum thickness e of the weld max .

[0025] According to an advantageous embodiment of the application, the tolerance interval IT is determined as a function of the slope tolerance of the joint with respect to the inter-blade surface of the disc.

[0026] The application also relates to a bladed disc for a turbomachine, comprising a plurality of blades joined to stubs on the disc at a radial joining height h by orbital friction welding, notably the radial joining height h measured from the inter-blade surface of the disc being greater than or equal to a critical threshold radial height h SC , the radial height being added to half the maximum thickness e max of the weld.

[0027] According to an advantageous embodiment of the application, the bladed disc corresponds to a moving wheel intended to be arranged upstream of a flow separation nozzle in an axial turbomachine.

[0028] The bladed disc is manufactured according to the method for manufacturing a bladed disc according to the application.

[0029] The measures of the application are particularly advantageous in that the radial height of the welding plane determined by the method according to the design of the bladed disc makes it possible to determine the dimensions of the blades and of the stubs, so as to ensure the optimal radial position of the welded joint. Thus, the stress constraints imposed on the joint can be predicted before manufacturing the bladed disc, so as to improve the structural and dimensional quality of the joint and of the manufactured disc.

[0030] The method for manufacturing a bladed disc of the application makes it possible to have considerable time and cost savings, since it makes it possible to avoid the technique in the prior art in which it is necessary to wait for a first welding test to make a cut on a test piece intended to approximately verify the radial position of the welded joint. In fact, the method according to the application corresponds to a predictive method for optimizing the height of the joint during the design phase of the blades, and makes it possible to integrate this constraint directly into the optimization of the shape of the blades.

[0031] It will be understood that each detail of the following embodiments can be combined with each other detail of the other embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 a perspective view of a bladed disc according to the application is shown; Figure 2 a side view of a blade of a bladed disc Figure 1 joined to a stub extending radially outward from the inter-blade surface of said disc by orbital friction welding is shown schematically; Figure 3a side view of a blade of Figure 2 in which the misaligned joint exhibits a tilt with respect to the nominal welded joint; Figure 4 a segment of a blade and / or of a stub in the vicinity of the welded joint visible in Figure 2 ; Figure 5 a joint segment when determining the average radius z A sweeping the segment from a point A on the perimeter of the segment Figure 4 ; Figure 6 a joint segment when determining the average radius z B sweeping the segment from a point B on the perimeter of the segment Figure 4 ; Figure 7 a perspective view schematically showing the connection of a blade to a disc stub by means of the joint segment shown in Figures 4 to 6 during orbital friction welding; Figure 8 a map of the amplitude of the average ray z i sweeping the joint segment at any point i of the perimeter of the joint segment; Figure 9 a joint segment of Figure 5 , showing three markers for measuring the maximum thickness of the welded joint, in which two of these joint segments are identical; Figure 10A is a first graph representing the estimated thickness of the welded joint with respect to the actual measured points, the local width along the joint segment of Figure 6 , and the variation with respect to a first reference point located at 1 / 4 of the total extent of the segment; Figure 10B is a second graph representing the estimated thickness of the welded joint with respect to the actual measured points, the local width along the joint segment of Figure 6 , and the variation with respect to a second reference point located at 1 / 2 of the total extent of the segment; Figure 10C is a third graph representing the estimated thickness of the welded joint with respect to the actual measured points, the local width along the joint segment of Figure 6 , and the variation with respect to a third reference point located at 3 / 4 of the total extent of the segment. DETAILED DESCRIPTION

[0033] In the following description, the terms "inboard" and "outboard" refer to the positioning with respect to the axis of rotation of the axial turbomachine and / or the central axis of the blade rotor disc. The axial direction corresponds to the direction along the axis of rotation of the turbomachine, the length being measured in the axial direction. The width is measured in the circumferential direction. The radial direction is perpendicular to the axis of rotation. Upstream and downstream refer to the main flow direction of the flow in the turbomachine.

[0034] The dimensions of the figures are not drawn to scale, in particular the thicknesses or radial dimensions are exaggerated in order to facilitate the reading of the figures.

[0035] Figure 1 A perspective view of a blade disc 2 according to the application is shown.

[0036] The blade disc 2 comprises a plurality of blades 4 joined by orbital friction welding to stubs 6 extending radially outwards from the inter-blade surface 8 of said disc 2. The welding is explained later in the present description.

[0037] Advantageously, the welding forms a joint 10 (shown in dotted line) between each blade 4 and the corresponding stub 6, said joint 10 being arranged at a radial joint height h measured from the inter-blade surface 8 of the blade disc 2.

[0038] The blade disc 2 is a mobile wheel intended to be arranged upstream of an air flow separation nozzle in a turbomachine. To this end, the inter-blade surface 8 corresponds to an air guiding surface of the fluid flow along and through the rotor. Alternatively, the blade disc 2 can correspond to a drum rotor belonging to a high or low pressure compressor.

[0039] Preferably, the disc 2 is a so-called "dual material" disc containing two different titanium alloys. For example, the blades 4 can be made of a Ta6v alloy and the disc can be made of one of the following alloys: Ti17, Ti575, Ti1023.

[0040] Advantageously, the mixture of two different titanium alloys (Ta6v and Ti17) presents an easier machinability compared to a solution based on Ti17 alloy only for example, and makes it possible to achieve an increase in quality, in particular due to the fact that the density of Ta6v is slightly lower than that of Ti17.

[0041] Indeed, the Ti17 alloy is preferentially chosen for the disc part for its good fatigue properties in high cycle fatigue (HCF) and low cycle fatigue (LFC). A Ti17 disc will also show a larger burst speed margin than Ta6v. For the blades, the Ta6v alloy is chosen because it provides the blades with a higher elongation at break (better impact resistance) and a better crack propagation resistance, thus better durability under low energy impacts.

[0042] Thus, the joint 10 corresponds to the limit of separation of the two different titanium alloys. To this end, the lower the radial height h of the joint 10, the greater the radial extent of the blade 4, which will enable the blade 4 to better resist the impact of the debris, since the properties of the titanium alloy forming the blade 4 are chosen to be more resistant to impact (low and high energy) than those of the alloy forming the disc. However, the joint 10 must be arranged above the critical threshold delimiting the critical zone (which will be explained later in the present description). In this respect, the present invention seeks to position the joint 10 in an optimized manner and as close as possible to the critical threshold. Another alternative would be to increase the radial height h of the joint 10, but this would imply a short column 6 with a high radial extent, which means a short column on the disc side with lower stiffness during welding. However, the stiffness of the short column to be welded is essential to ensure a solid weld. A too flexible short column would disperse part of the energy provided by the machine into its deformation, rather than keeping part of the energy in pure friction energy. If the short column is flexible, the eccentricity actually seen at the short column will be reduced.

[0043] The present invention proposes a device for determining the optimal radial height of the joint 10 to guarantee the structural and dimensional quality of the weld 10 and of the blade disc 2.

[0044] In this respect, the radial joint height h is determined during the manufacturing method according to the present invention. This manufacturing method comprises a step of determining the radial joint height h as a function of the maximum thickness e max of the weld. The step of determining the position of the joint 10 is carried out before the manufacturing of the blade disc 2 according to the design of the blade disc 2 and will be explained later in the present description.

[0045] Figure 2 a side view of one of the blades 4 of the blade disc 2 is schematically shown. Figure 1

[0046] It can be observed that the joint 10 has a diabolo or butterfly shape, the peripheral end of which (in the radial direction) is wider than the inner central part of the joint 10, due to the concentration of the excess material displaced during orbital welding. To this end, the maximum thickness e max is measured at the peripheral end of the joint 10.

[0047] It can also be seen that the welded joint 10 comprises a welding plane 10.1, which is shown in a central position with respect to the maximum thickness e max of said joint 10. Advantageously, the welding plane 10.1 corresponds to the optimal radial joint position h. The optimal radial joint position h is arranged radially above the determined critical threshold SC.

[0048] ​In practice, the positioning of the welded joint 10 must guarantee that the blade disc 2 does not break in the event of a deviation in the material properties, i.e. in the event of a crack propagating in the blade 4 in said joint 10.

[0049] In this respect, the critical threshold SC corresponds to the limit beyond which a crack initiated in the blade 4 does not propagate towards the disc 2, said critical threshold SC comprising a radial height h SC .

[0050] Advantageously, the radial height h SC of the critical threshold SC is such that it makes it possible to distinguish a first zone, classified as "N1", in which a crack initiated, for example in the event of an impact of a piece of debris, can lead to the propagation of a crack in the rotor hub, and thus to the growth of a crack in the rotor body, and thus to a burst, which corresponds to the "dangerous engine effect" according to the following certification definition: "CS-E510" of the European Aviation Safety Agency (EASA). The critical threshold SC also distinguishes a second zone "N2" in which a deviation in one of the uncontrolled material and / or process properties can produce a "main engine effect". To this end, the critical threshold SC is generally specified as a threshold N1 / N2.

[0051] The fleet experience has shown that the zone of the blade 4 above a certain height in the blade (relative to the height of the blade / disc fillet) can be considered as non-dangerous or non-critical. The blade breakage is then controlled and does not lead to a burst of the rotor, thus satisfying the "CS-E515" certification specification.

[0052] The radial height h SC of the critical threshold can be determined by crack propagation calculations from appropriate damage tolerance methods (for example 3D crack propagation simulations), tests or experience accumulated on similar blisks.

[0053] Preferably, the radial height h SC of the critical threshold is calculated based on the value of the blade / disc radius. More preferentially, the radial height h SC is greater than or equal to twice the radius of the fillet between the blade and the flow channel.

[0054] In the configuration of the blade 4 of the blade disc 2, preferentially, the radial height h SC is equal to twice the radius R of the connecting fillet 7 of the stub 6.

[0055] Advantageously, the welded plane 10.1 is arranged radially above the critical threshold SC, the welded joint 10 making it possible to avoid the risk of a "dangerous engine effect" in the turbomachine.

[0056] In order to position the welding plane 10.1 optimally according to the design of the blade disc 2, the manufacturing method according to the application comprises a step of estimating a tolerance interval IT of the joint 10 comprising e max . Preferably, the determined critical threshold SC corresponds to the lower limit of the tolerance interval IT.

[0057] To this end, the radial joint height h is greater than or equal to twice the radius R of the fillet 7, plus half the maximum thickness e max and / or plus half the tolerance interval IT.

[0058] In this configuration, the radial joint height h is between twice the radius R and 4R, and more precisely between 2.2R and 3R.

[0059] Preferably, the tolerance interval IT is a function of the maximum thickness e max of the joint 10. The tolerance interval IT can also or alternatively be determined as a function of at least one of the following factors: - the parameter variability during welding, meaning a total joint thickness that is more or less thick compared to the nominal joint (the parameter variability depending on the oscillation frequency, the welding pressure, etc.); - the accuracy of the radial position of the joint 10 (depending on the tolerance of the height on the blade and / or on the stub side and depending on the variability of the movement of the tool used to perform the welding; - the inclination of the joint 10 with respect to the outer surface 8, the inclination corresponding to a variability of the inclination (the inclination depending on the alignment of the blade and the stub before welding).

[0060] Figure 3 An example of the inclination ob present between the two peaks respectively belonging to the misaligned joint 10' and to the joint 10 (here corresponding to a nominal welded joint without geometric defects) is shown, the appearance of the inclination at the welded joint corresponding to a variability of the inclination which can depend on at least one of the following reasons: the influence of the planar and out-of-plane misalignment of the two surfaces to be welded; the misalignment (concentricity) between the two stubs; the torque of the segments and of the welding material to be welded.

[0061] With reference to Figure 2 and Figure 3 , the tolerance interval IT is greater than or equal to the maximum thickness e max of the welded joint. The tolerance interval can extend radially by about 5% to 70%, preferably by about 10% to 50% more than the maximum thickness e max .

[0062] Preferably, the joint 10 is radially distant from the critical threshold SC by a distance d corresponding to the radial extent of the heat-affected zone (ZAT) of the stub 6.

[0063] The radial engagement height h can be defined using the following equation: h = h SC + IT / 2 More preferably, the tolerance interval IT can be estimated before the manufacturing of the bladed disc 2, by estimating the maximum thickness e max Advantageously, e max is determined as a function of the geometric parameter z of the section of the blade 4 and of the stub 6 at the engagement 10. Preferably, said section corresponds to a flat section. The stub 6 and the corresponding blade 4 of the disc intended to be orbitally friction welded have the same engagement section.

[0064] The determination of e Figures 3 to 5 as a function of the geometric parameter z will be explained in max

[0065] Advantageously, the estimation of the tolerance interval IT before the manufacturing makes it possible to overcome the methods of verification IT of the prior art, for example by avoiding performing a series of samplings and performing cuts to verify the position of the welded engagement by measurements during the manufacturing. Thus, the present invention makes it possible to ensure considerable efficiency and savings during the manufacturing of the bladed disc 2.

[0066] Figure 4 The section 11 of the blade 4 and / or of the stub 6 at the welded engagement 10, visible in Figure 2 , is schematically illustrated. Preferably, the section 11 is identical for the blade 4 and for the stub 6 of the disc 2.

[0067] The section 11 is modeled by the aerodynamic profile 4.1 of the blade 4, the blade 4 comprising a section widened by a surplus thickness e, preferably corresponding at least to the eccentricity e of the orbital oscillating movement during the welding. The eccentricity e corresponds to the offset value of the tool (for holding the blade) and of the disc with respect to a reference center, so that the orbital oscillating movement can be produced. In other words, the eccentricity corresponds to the distance between the axis of rotation of the tool and the center point around which the tool performs the orbital movement.

[0068] The surplus thickness e is not necessarily constant around the profile 4.1, the surplus thickness e can present a variation around said profile 4.1.

[0069] It should be noted that, before the orbital friction welding, a sacrificial volume of material (substantially radially extending) is provided on each of the blade 4 and the stub 6 to be assembled. This sacrificial volume is expelled outside the contact interface between the sections 11, thus forming burrs, commonly called: “flash”, which will be removed, for example by machining, to form Figure 1 ​The blade disc 2 is shown. However, the flash has the risk of causing material to recirculate in the narrowest region of the contact section and of creating a recess in the welded joint, which is detrimental to the quality of the weld.

[0070] Advantageously, the widening of the section 11 by the amount of eccentricity e of the section 11 makes it possible to enlarge the contact surface during orbital friction welding, thus ensuring the thermal homogeneity during welding precisely in the final section 4.1 of the blade 4. The fact is that if we add a surplus thickness e at least equal to the value of the amount of eccentricity, this means that the points of the final aerodynamic surface 4.1 are always in contact (between the two stubs) during welding. Unlike the points in this surplus thickness e, these points are in contact with the opposite surface only during a part of the orbital oscillation movement by the orbital movement.

[0071] Thus, during welding, the material consumption rate remains constant on the right of the section 11, which makes it possible to avoid recirculation of material at the section of the final aerodynamic profile 4.1 of the blade, which is potentially harmful because this recirculation hinders the expulsion of impurities, and thus makes the mixing of the material of the stubs with the material of the blade homogeneous and continuous, thus making it possible to further preserve the aerodynamic profile of the blade and to obtain a solid joint.

[0072] The section 11 modelled makes it possible to establish a geometric parameter z. Indeed, z is the average value of the average radius z i of the section 11 swept by each point i of the periphery 11.1 of said section 11.

[0073] Each average radius z i corresponds to the average length z i,α of the ray z i which extends completely in the section 11 from the point i to the periphery 11.1 of said section 11 and sweeps said section 11. Preferably, the ray z i,α corresponds to the projection of the point i on the entire part of the periphery 11.1 opposite said point i.

[0074] Advantageously, the variation of the average radius z i on the periphery of the section 11 to be welded physically represents the homogeneity of the length to be sheared during rotation (orbital movement during welding) and represents the homogeneity of the flow of material expelled in the flash along the profile of the blade. This represents the homogeneity of the contaminants ejected from the weld.

[0075] In this respect, the determination of the geometric parameter z comprises determining the average radius z i of a plurality of points i on the entire periphery 11.1.

[0076] Preferably, the determination of the geometric parameter z is an automated process using a computer algorithm. In this regard, an algorithm can be adopted which applies a "ray-tracing" type method, which can also be referred to as "ray-tracing".

[0077] Advantageously, the inventors have wisely adopted an innovative approach by introducing a ray-tracing technique which has so far been unknown in the field of mechanics. The inventors have realised that this is the best way to characterise the joint section for the orbital friction, in order to more accurately estimate the radial position (height) of the weld before the orbital welding operation.

[0078] The ray-tracing method on the section 11 can be performed using the following steps: - modelling the first section 11 (visible in Figure 4 ) based on the final aerodynamic profile 4.1 of the blade, in which a surplus thickness e is added (which has the same value as the amount of eccentricity planned to be applied to the tool during the orbital welding); and - dividing the perimeter 11.1 uniformly into a plurality of points i, from which the rays z i,α will be projected, preferably at about 2000 points i uniformly distributed (this number can vary depending on the desired calculation accuracy); and - sweeping the projected rays z i,α from the first point i of the perimeter 11.1 through the entire section 11, preferably the number of projected rays z i,α depends on an angle a between 0.001° and 10°; and - measuring the average length z i,α of all the rays z i projected from the first point i; and - repeating the projection step of the rays z i,α and the measurement step of the average length z i continuously for all the points i of the perimeter 11.1 ; and - calculating the average length of all the average lengths z i measured from each of the points i, to arrive at the geometric parameter z of the joint section.

[0079] Figure 5 and Figure 6 show examples of the projection of the rays z A,α and z B,α emanating from points A and B of the perimeter 11.1, respectively. These are two schematic examples of the average length z i,α of all the rays z i determined by the ray-tracing method described above.

[0080] The two points A and B correspond to the average length z Aand the average length z B of two points. To this end, the determination of the geometric parameter z of the section 11 corresponds to the calculation of the average of all average lengths z i for example including the 2000 average lengths z A and z B .

[0081] Figure 5 The section 11 is shown when determining the average radius z A of the section swept from the point A of the perimeter 11.1.

[0082] It can be seen that from the point A, a plurality of rays z A,α are projected on a portion of the perimeter 11.1 visible from said point A. In this configuration, the rays z A,α can be between two extreme rays z A,α tangent to the perimeter 11.1.

[0083] The number of projected rays z A,α can depend on the angle a chosen which makes it possible to give the precision of the establishment of the average radius Z A . To this end, the angle a can be between 0.001 ° and 10°.

[0084] The average radius Z A thus corresponds to the average of all projections z A,α .

[0085] Figure 6 The section 11 is shown when determining the average radius z B of the section swept from the point B of the perimeter 11.1.

[0086] Preferably, for a plurality of points i of the perimeter 11.1, the angle a is identical for all projections of the rays z i,α . Preferably, the number of points i of the perimeter 11.1 from which a ray will be projected is of the order of 2000 points, this number being able to vary according to the desired calculation precision.

[0087] Similarly to the point A, the rays z B,α are projected from the point B on a portion of the perimeter 11.1 visible at said point B. The average ray z B corresponds to the average of all projections z B,α .

[0088] The geometric parameter z is thus the average of all average radii z i of the points i of the entire perimeter 11.1, including the average radii z A and z B .

[0089] The geometric parameter z corresponds to a geometric dimension which can be expressed in mm. Advantageously, this parameter z is the best dimension which best distinguishes the geometry of the section 11. Indeed, during orbital friction welding, the section 11 comprises a projection ray z i,α The surface of the section 11 can be considered as a mixed surface of materials.

[0090] The geometric parameter z makes it possible to take into account the particularity of the orbital friction welding during the manufacturing process. Indeed, the friction force provided during the welding rotates periodically, which means that the welding points at the ends of the section 11 of the stub (for example, points A or B) see a small portion of the section 11 of the blade located between the two extreme projection radii (z A,α or z B,α ), thus the two extreme projection radii can be considered as the equivalent length of the material to be sheared.

[0091] Moreover, the parameter z is relevant because this parameter z makes it possible to reflect the curvature of the particular shape of the perimeter 11.1 better than the area of the section 11 or the chord of the profile of the section 11.

[0092] According to the two embodiments, the maximum thickness e max , e max is determined as a function of the geometric parameter z and of additional parameters: The first embodiment comprises determining e max as a function of the geometric parameter z and of at least one of the following orbital friction welding parameters: eccentricity (corresponding to the amount of eccentricity e of the orbital oscillation movement during the welding), frequency (oscillation speed), and forging pressure (force applied to the section during the final forging phase after the oscillation movement has stopped). Advantageously, the welding parameters can be predefined as input set points on the welding machine before performing the welding and / or can be measured during the welding.

[0093] The second embodiment comprises determining e max as a function of the geometric parameter z and of the material consumption rate during the orbital friction welding. The material consumption rate (expressed in mm / s) can be determined empirically, for example after actual measurements during a parameterized orbital friction welding with the same parameters as the orbital friction welding of the blades of the blade disc, i.e. using the same joint section 11 modeled for example on a test specimen similar to the section 11 of Figure 4 or by an analytical determination of the material consumption rate as an estimation of the consumption rate as a function of the following orbital friction welding parameters (eccentricity, frequency, and forging pressure).

[0094] The welding parameters (eccentricity, frequency, and forging pressure) are used to estimate e maxThis can be done by means of artificial intelligence.

[0095] The maximum thickness e is determined as a function of the geometric parameter z max So that we can determine that the greater the parameter z, the greater the e determined max The greater.

[0096] Figure 7 The oscillations 12 are schematically shown during the orbital friction welding, by means of which Figures 4 to 6 The perspective view of the joining section 11 shown makes the blade 4 connect to the stub 6 of the disc 2.

[0097] The welding plane 10.1 is determined as a function of the design of the disc 2, which makes it possible to determine the dimensions of the blade 4 and the stub 6, in order to ensure the optimal radial position of the joint 10.

[0098] The manufacturing method of the invention comprises the application of oscillations 12 by means of a welding machine (not shown) comprising a tool for holding the blade 4. In this configuration, preferably, the lower end 4.2 of the blade 4 comprises a reinforcement 4.3 which, after welding, will be machined together with the volume 6.1 of the reinforcement of the stub 6 on the disc 2.

[0099] Advantageously, the orbital oscillations 12 comprise an amplitude that can be controlled by an electric motor which makes it possible to oscillate very quickly while minimizing energy losses and also ensures the self-centering of the oscillations 12 at the end of the welding.

[0100] Furthermore, the orbital welding of the blade 4 makes it possible to ensure a permanent relative movement of the blade 4 with respect to the stub 6 on the right side of the joining section, which makes it possible to obtain greater temperature uniformity and better material expulsion. In this configuration, due to better thermal heterogeneity, the orbital friction welding process of the invention will produce a lower stress gradient and ultimately a smaller deformation over the entire manufacturing range.

[0101] Preferably, the joining section S of each of the blade 4 and the stub 6 comprises a total surface area greater than or equal to 200 mm 2 and less than or equal to 7000 mm 2 , more preferably between 2000 mm 2 and 3000 mm 2 .

[0102] Figure 8 The map of the amplitude of the average ray z i is shown which sweeps the joining section 11 at each point i of the periphery 11.1 of the joining section.

[0103] On the right side of the scale Figure 8 corresponds to the map of the variation of the value of z i , which is normalized to 1, i.e. z of the section 11i The maximum value is 1.

[0104] It can be seen that point i at the periphery 11.1 at the ends 11.2 and 11.3 of segment 11 has rays z emanating from said point i. i,α The average value z i The average value z i Ray z emitted from point i located between ends 11.2 and 11.3 i,α The average value z i It is the smallest in comparison.

[0105] Advantageously, the geometric parameter z (the ray z emitted from point i) i,α All average z i The total average value z can take into account the specific details of the segment's shape, such as the segment's curvature, which is different from simple area measurements or other methods in the prior art, which cannot take into account these details. The geometric parameter z's inherent ability to consider these details of the shape of the joining segment 11 makes it possible to determine the maximum thickness e more accurately. max Then determine the radial height of the welded joint.

[0106] It should be noted that the prior art does not propose a method for estimating the weld joint. max No solution was provided, and no literature discloses any e max Correlation between the shape of the segment and the shape of the segment.

[0107] Typically, it is important to note that the two sections to be welded have a perfectly circular configuration, which enables optimal orbital welding. This configuration ensures completely uniform and constant mixing, thus guaranteeing a stable temperature rise of the material. Furthermore, the circular shape of the sections allows for frictional uniformity exceeding 360° without any shape change.

[0108] The inventors possess an inventive method that incorporates the aforementioned ray tracing method (an unconventional technique in the field of mechanics) to characterize the joint segment, taking into account all friction directions. Specifically, this involves using rays z emitted from each of all points i around the perimeter of the segment. i,α The scanning section is similar to the movement of mixed materials between contacting surfaces during rail welding, the movement being in all directions and exceeding 360°.

[0109] This correlation between the mixing physics during rail friction and the theoretical calculation of parameter z offers the possibility of predicting material mixing behavior even before rail welding. Therefore, parameter z enables the prediction of post-weld parameters (e) at an early stage of the process (when the shape of the joint segment is modeled and before welding). maxto make more accurate estimates.

[0110] In fact, Figure 9 and Figures 10A to 10C The accuracy of the determination of the final radial height of the welded joint is clearly shown, since the e max (whose height depends on e max ) estimated for the joint section 11 max is very close to the actual e max measured after the orbital welding.

[0111] Figure 9 are shown Figure 8 of the joint section 11 which shows three markers for measuring the thickness of the welded joint 11, of which two of these joint sections 11 are identical. Each marker defines the total local width of the section along the respective direction shown by the dashed line.

[0112] Figures 10A to 10C are shown Figure 9 of the joint of the section 11 of the normalized variation of the thickness of the joint measured on the made weld and estimated numerically using the parameter z.

[0113] Figure 10A is a first graph which shows the variation of the estimated thickness of the welded joint (see curve S) compared to the actual measured value of said thickness, point P, located to the right of the first marker at 1 / 4 of the total extent of the section 11 visible in Figure 9 .

[0114] Figure 10B is a second graph which shows the variation of the estimated thickness of the welded joint (see curve S) compared to the actual measured value of said thickness, point P, located to the right of the second marker at 1 / 2 of the total extent of the section 11 visible in Figure 9 .

[0115] Figure 10C is a third graph which shows the variation of the estimated thickness of the welded joint (see curve S) compared to the actual measured value of said thickness, point P, located to the right of the third marker at 3 / 4 of the total extent of the section 11 visible in Figure 9 .

[0116] With reference to Figures 10A to 10C , according to the present application, preferably the curve S is obtained by means of a simulation provided by artificial intelligence, based on the determination of e max as a function of the parameter z.

[0117] The welding is carried out on the same machine, with the welding parameters remaining constant, i.e. the eccentricity, the oscillation frequency, the forging speed and the pressure remaining constant, only the shape of the segments being changed.

[0118] As an indication, for a parameter z equal to 25 mm, the maximum measured thickness of the welded joint from the two segments 11 is equal to 0.97 mm.

[0119] It has been determined that an increase in the value of the parameter z (by changing the profile of the joining segments during modelling) is associated with an increase in e max Similarly, a variation in e max is also associated with a variation in the radial height h.

[0120] From the graphs it can be observed that for each of the three measurement markers the difference (error amplitude) between the simulation (carried out upstream of the orbital welding) and the measurement of e max after the welding operation is very small, which demonstrates that the present application makes it possible to ensure an accurate determination of the height of the welded portion, thus a simulation of the orbital welding which is the most accurate and closest to reality.

[0121] It can also be observed that the S curve has a generally basin-like shape, due to the fact that the thickness at the peripheral ends of the welded joint is wider than at the centre, due to the concentration of the excess material displaced during the orbital welding, which gives the welded joint a roughly diabolo or straw shape (as shown in Figure 2 Fig. 3).

Claims

1. A manufacturing method for manufacturing a bladed disc (2) comprising blades (4) joined by orbital friction welding to stubs (6) on the disc (2) and extending radially outwards, the method comprising the step of determining the radial joint height h between the blades (4) and the stubs (6), characterised in that, said radial engagement height h is determined as a function of the maximum thickness e of the weld max , the greater said radial engagement height h, the greater said maximum thickness e of the weld max , the maximum thickness e of the weld being determined by a geometrical parameter z of a section (11) of the blade (4) and of the stub (6) at the engagement (10), wherein z is an average value of the average radius z i , swept through said section (11) at each point i of the periphery (11.1) of said section (11), the determined maximum thickness e of the weld max , the greater, the smaller said geometrical parameter z.

2. The manufacturing method according to claim 1, wherein, said maximum thickness e of said weld max Also determined by at least one of the following orbital friction welding parameters: - eccentricity; - frequency; and - forging pressure.

3. The manufacturing method according to claim 1, wherein, the maximum thickness e of the weld max Also determined by the material consumption rate during orbital friction welding.

4. The manufacturing method according to claim 3, wherein, The material consumption rate is measured during a parameterized orbital friction welding, which is performed with the same parameters as the orbital friction welding of the blade (4).

5. The manufacturing method according to claim 3, wherein, The material consumption rate is determined as a function of the following orbital friction welding parameters: - eccentricity; - frequency; and - forging pressure.

6. The production method according to any one of claims 1 to 5, wherein said radial engagement height h measured from the inter-leaf surface (8) of the disc (2) is greater than or equal to a radial height h of a critical threshold (SC) SC , said radial height plus half a tolerance interval IT determined as a function of said maximum thickness e max of the weld.

7. The manufacturing method according to claim 6, wherein said tolerance interval IT is greater than or equal to said maximum thickness e of the weld max .

8. The production method according to claim 6 or 7, wherein The tolerance interval IT is determined as a function of the slope tolerance of the joint (10) with respect to the inter-blade surface (8) of the disc (2).

9. A bladed disc (2) for a turbomachine, comprising a plurality of blades (4) joined to stubs (6) on the disc (2) at a radial junction height h between the blades (4) and the stubs (6) by orbital friction welding, characterized in that, said radial engagement height h measured from the inter-blade surface (8) of the disc (2) is greater than or equal to a critical threshold (SC) of radial height h SC said radial height plus half of said maximum thickness e max of the weld.

10. The vane disc (2) according to claim 9, wherein The blade disc (2) corresponds to a mobile wheel intended to be arranged upstream of a flow separation nozzle in an axial turbomachine.

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