Method for producing plurality of turbine engine blades

Abstract

The invention relates to a method (100) for producing a plurality of blades (10) having a height (Ha), the method comprising: providing a mould (30) comprising an internal cavity delimited by an inner side surface (34) of the mould axially symmetric about a longitudinal axis (X), the side surface (34) extending along the longitudinal axis (X) to a height (Hf) greater than or equal to the height (Ha), the side surface (34) defining a plurality of sections (34i) of the longitudinal axis (X) perpendicular to the radius (Rfs), the ratio of the height (Hf) of the side surface (34) to the radius (Rfs) of the section (34i) being less than or equal to 2.0 for each section (34i); rotating the mold about the longitudinal axis at a rotational speed of between 200 rpm <-1 > and 800 rpm <-1 >; and pouring a material into the internal cavity so as to form a tubular member (20) centrifugally along the longitudinal axis (X).

Description

Technical Field

[0001] The present description relates to a method for producing a plurality of turbine engine blades. Background Art

[0002] In order to manufacture turbine engine blades, it is known to first produce a tubular part 20 (also called a “barrel”) and to machine a blank of a turbine engine blade 10 or directly a turbine engine blade 10 into said tubular part. Figure 1 As can be seen in FIG. 1 , the tubular member 20 extends between the first end and the second end along the first axis A1 and has a thickness in the radial direction. Therefore, the blades 10 can be machined to the thickness of the tubular member 20 by being arranged circumferentially one by one around the first axis A1. Figure 1 As can be seen in b, each blade 10 extends substantially parallel to the first axis A1.

[0003] Ideally, if Figure 2 As shown in , the radial inner surface 24 of the tubular component 20 has a straight profile 25 aligned with the first axis A1 in a sectional plane including the first axis A1. However, the tubular component 20 is usually obtained by vertical centrifugal casting, which provides a parabolic profile for the inner surface 24 of the tubular component 20. Therefore, the thickness e1 at the first end of the tubular component 20 is greater than the thickness e2 at the second end. Therefore, the tubular component 20 includes a non-functional portion 22 or excess material that does not participate in the formation of the blade at the first end. Therefore, the non-functional portion 22 is eliminated during the manufacture of the blade 10, which reduces the yield of the production method. Summary of the invention

[0004] A method for producing a plurality of turbine engine blades having a height is provided, the method comprising:

[0005] - providing a mould comprising an internal cavity, the internal cavity being delimited by an inner side surface of the mould being axisymmetric about the longitudinal axis, the side surface extending along the longitudinal axis to a height greater than or equal to the height of each blade, the side surface defining a plurality of segments perpendicular to the longitudinal axis, each segment of the side surface having a radius, the side surface of the mould being such that for each segment, a ratio of the height of the side surface to the radius of the segment is less than or equal to 2.0;

[0006] - positioning the mould so that the longitudinal axis is aligned with the gravitational field,

[0007] - rotating the mould about the longitudinal axis at a speed of between 200 and 800 rpm,

[0008] - Pouring material into the internal cavity of the mould so as to form, by centrifugation, a tubular part extending along the longitudinal axis.

[0009] The obtained tubular component extends longitudinally between the lower end and the upper end to a height that coincides with the height of the side surface of the mold. In addition, the tubular component has an outer surface that coincides with the side surface of the mold. The outer surface of the tubular component is axisymmetric about the longitudinal axis. The tubular component defines a plurality of sections perpendicular to the longitudinal axis. Each section of the tubular component is associated with a corresponding section of the side surface of the mold located at the same longitudinal position. Each section of the tubular component has an outer radius that coincides with the radius of the corresponding section of the side surface of the mold.

[0010] Furthermore, the tubular component thus obtained has an inner surface which substantially has the shape of a truncated cone around the longitudinal axis. In other words, the profile of the inner surface of the tubular component is substantially a straight line segment forming an angle with the longitudinal axis in a sectional plane including the longitudinal axis. Such a profile of the inner surface of the tubular component makes it possible to reduce or even eliminate the amount of material forming the non-functional part of the tubular component. Thus, the method allows reducing the amount of initial material required to obtain a plurality of blades. In other words, the method improves the casting rate when manufacturing a plurality of turbine engine blades.

[0011] The term "functional" used with respect to a portion of a tubular component allows indicating whether the portion so described is used to form one or more blades. Thus, a functional portion of a tubular component is a portion containing blades having a limited excess thickness in its material (this excess thickness is of the order of millimeters, preferably less than 10 mm, more preferably less than 5 mm). The functional portion of the tubular component may have a profile of a parallelogram shape in a sectional plane comprising the longitudinal axis, wherein one of the sides coincides with the outer surface of the tubular component. In a particular embodiment, the functional portion of the tubular component has a rectangular profile in a sectional plane comprising the longitudinal axis. In contrast, a non-functional portion is a portion that does not participate in the formation of the blades. Therefore, the amount of material forming the non-functional portion is lost during the manufacture of the blades. The non-functional portion may be located radially to the inside with respect to the functional portion.

[0012] The side surface of the mould may be such that for each segment the ratio of the height of the side surface to the radius of the segment is between 0.5 and 1.5, preferably between 0.75 and 1.25, more preferably equal to 1.0.

[0013] The height of the side surface of the mould may be between 150 mm and 2000 mm.

[0014] Each section of the side surface of the mold extends in a plane perpendicular to the longitudinal axis. Each section has a circular shape centered on the longitudinal axis.

[0015] The radius of each segment of the side surface of the mold can be defined as the distance separating the side surface from the longitudinal axis in a plane perpendicular to the corresponding longitudinal axis of the segment. The side surface may include at least two segments with different radii from each other. The radius of each segment of the side surface can be determined according to the longitudinal position of the segment on the side surface, for example according to a linear law. Alternatively, the radius of each segment of the side surface may be the same.

[0016] The radius of each section of the side surface of the mould may be between 150 mm and 1500 mm.

[0017] Each section of the tubular member extends in a plane perpendicular to the longitudinal axis.

[0018] In each section of the tubular member, an outer surface of the tubular member may have a circular shape centered on the longitudinal axis.

[0019] The outer radius of each section of the tubular component can be defined as the distance separating the outer surface of the tubular component from the longitudinal axis in a plane perpendicular to the corresponding longitudinal axis of the section. The tubular component may include at least two sections having outer radii that are different from each other. The outer radius of each section of the tubular component can be determined according to the longitudinal position of the section on the tubular component, for example according to a linear law. Alternatively, the outer radius of each section of the tubular component may be the same.

[0020] In each section of the tubular member, the inner surface of the tubular member may have a circular shape centered on the longitudinal axis.

[0021] Each segment of the tubular component may have an inner radius. The inner radius of each segment of the tubular component may be defined as the distance separating the inner surface of the tubular component from the longitudinal axis in a plane perpendicular to the corresponding longitudinal axis of the segment. The inner radius of each segment of the tubular component may be determined according to the longitudinal position of the segment on the tubular component, for example according to a linear law.

[0022] The inner surface of the tubular member may have a shape of a truncated cone having a radius at the apex of γ=g / (ω 2 (Re0-e t )) defined by the half-width, where

[0023] g is the acceleration due to gravity;

[0024] ω is the rotational speed of the die around the longitudinal axis;

[0025] Re0 is the outer radius of the section of the tubular member located at the lower end of the tubular member;

[0026] e t is satisfied (e t / (Re0-e t))≤theoretical thickness of 0.7.

[0027] The mould may comprise at least one tubular wall extending along the longitudinal axis. The tubular wall may comprise a side surface. The tubular wall of the mould may extend along the longitudinal axis between a lower end and an upper end.

[0028] The obtained tubular component may have a plurality of sections perpendicular to the longitudinal axis, and the method further comprises: determining the amount of material to be poured into the mold so that the thickness of each section of the tubular component is greater than or equal to satisfying (e t / (Re0-e t ))≤0.7 theoretical thickness e t , where Re0 is the outer radius of the section of the tubular component located at the lower end of the tubular component. This makes it possible to ensure that the tubular component is thick enough for the production of turbine engine blades, regardless of the longitudinal position involved on the tubular component; in other words, the minimum theoretical thickness for the production of turbine engine blades is independent of the longitudinal position involved on the tubular component.

[0029] The thickness of each section of the tubular component may be considered in a radial direction relative to the longitudinal axis.The thickness of each section of the tubular component may be defined as the difference between the outer radius and the inner radius of the section.

[0030] The tubular member may include at least two sections having different thicknesses from each other. Alternatively, the thickness of each section of the tubular member may be the same.

[0031] Specifically, the thickness of the section of the tubular member located at the upper end of the tubular member may be greater than or equal to the thickness satisfying (e t / (Re0-e t ))≤0.7, where Re0 is the outer radius of the section of the tubular component located at the lower end of the tubular component.

[0032] For each section of the tubular component, the functional portion of the tubular component may have a thickness in a radial direction relative to the longitudinal axis. The thickness of the functional portion may be greater than or equal to the theoretical thickness of each section of the tubular component.

[0033] The internal cavity of the mold may be defined by an internal lower surface of the mold and an internal upper surface of the mold, the lower surface and the upper surface being connected to the lower and upper ends of the side surfaces respectively, the lower surface and the upper surface being preferably each perpendicular to the longitudinal axis.

[0034] The lower surface and / or the upper surface of the mold may each be axisymmetric about the longitudinal axis.

[0035] The mold may include a lower wall and an upper wall each extending transversely to the longitudinal axis. The upper wall and the lower wall may be connected to the lower end and the upper end of the tubular wall of the mold, respectively. The lower wall and the upper wall may include an inner lower surface and an inner upper surface, respectively. The upper wall may include an opening for pouring material into the inner cavity. The lower wall may not have any openings.

[0036] The side surface of the mold can generally be a rotating cylinder around the longitudinal axis. The rotation speed of the mold around the longitudinal axis can be between 600 rpm and 800 rpm. This method allows to obtain a tubular part in which the mass of the non-functional part is less than or equal to 5% relative to the mass of the functional part of the tubular part.

[0037] The side surface of the mold may have the general shape of a truncated cone of revolution about the longitudinal axis, the truncated cone having a cross section that decreases in the direction of the gravitational field when the mold is positioned so that the longitudinal axis is aligned with the gravitational field. The rotation speed of the mold about the longitudinal axis may be between 200 rpm and 400 rpm, preferably between 300 rpm and 400 rpm. This method allows to obtain a tubular part in which the mass of the non-functional part is less than or equal to 5% relative to the mass of the functional part. In addition, this method advantageously has a low rotation speed of the mold, which allows to reduce the power required to rotate the mold about the longitudinal axis and therefore reduce the energy consumption of the method. In addition, this makes it possible to avoid certain problems inherent in high rotation speeds, such as vibrations, rotational imbalance or rotation speed limitations of the mold.

[0038] The side surface of the mold has a truncated cone shape having a radius at the vertex of β=g / (ω 2 (Re0-e t )) defined by the half-width, where

[0039] g is the acceleration due to gravity;

[0040] ω is the rotational speed of the die around the longitudinal axis;

[0041] Re0 is the outer radius of a section of the tubular member perpendicular to the longitudinal axis and located at the lower end of the tubular member;

[0042] e t is satisfied (e t / (Re0-e t ))≤theoretical thickness of 0.7.

[0043] Thus, the half angle at the vertex of the side surface of the mould is equal to the half angle at the vertex of the inner surface of the tubular component. Thus, the thickness of each segment of the tubular component is the same, regardless of the longitudinal position of the segment on the tubular component. This allows to further reduce or even eliminate the amount of material forming non-functional parts of the tubular component.

[0044] The side surface of the mold may include at least one protrusion formed annularly around the longitudinal axis. Such an annular protrusion allows the turbine engine blade to be partially preformed in an annular portion.

[0045] The annular protrusion may be an annular groove formed in the side surface of the mold.The annular protrusion may protrude radially from the side surface of the mold.

[0046] The material poured into the mold may be a metal alloy, preferably titanium aluminide (TiAl), more preferably a γ-TiAl alloy. Titanium aluminide advantageously has good mechanical strength at high temperatures and has a low density.

[0047] The material poured into the mould may be a γ-TiAl alloy, and the method may further comprise heating the material to a temperature between 1550° C. and 1700° C. for pouring into the mould. The material poured into the mould may be molten.

[0048] The method may further include machining the tubular member to form a plurality of turbine engine blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Other features, details and advantages will become apparent upon reading the following detailed description and upon examining the accompanying drawings, in which:

[0050] Figure 1 a perspective view schematically showing the different steps of a known method for producing a plurality of blades;

[0051] Figure 2 Schematically represented in Figure 1 a cross-sectional view of a tubular member used in the method;

[0052] Figure 3 is a functional diagram of a method for producing a turbine engine blade according to the present specification;

[0053] Figure 4 Schematically showing the first embodiment Figure 3 A perspective view of a mold used in the method;

[0054] Figure 5 The section plane IV-IV schematically shows Figure 4 A cross-sectional view of a mold;

[0055] Figure 6 Schematically represented in section plane VV Figure 4 A cross-sectional view of a mold;

[0056] Figure 7 Schematically showing the second embodiment Figure 3 A perspective view of a mold used in the method;

[0057] Figure 8 The section plane VII-VII schematically shows Figure 7 A cross-sectional view of a mold;

[0058] Fig. 9 Schematically showing the Figure 4 A variation of the mold of the first embodiment;

[0059] Fig.10 Schematically showing the Figure 7 A variation of the mold of the second embodiment. DETAILED DESCRIPTION

[0060] Reference now Figure 3 . Figure 3 is a functional diagram of a method 100 for producing a plurality of turbine engine blades 10. Each blade 10 is intended to extend to a height Ha between a root and a tip (or heel).

[0061] The production method 100 includes a first step 110. The first step 110 includes providing a mold 30. Referring first to a first embodiment of the mold 30, Figures 4 to 6 .

[0062] The mold 30 first includes a tubular wall 31 extending along a longitudinal axis X. In the following, directional qualifiers such as "longitudinal", "radial" or "circumferential" are defined with reference to the longitudinal axis X. The tubular wall 31 of the mold 30 can extend between a lower end and an upper end along the longitudinal axis X. The mold 30 also includes a lower wall 33 and an upper wall 32, each extending transversely to the longitudinal axis X. The upper wall 32 and the lower wall 33 are connected to the upper end and the lower end of the tubular wall 31 of the mold 30, respectively. The upper wall 32 and the lower wall 33 extend radially inward from the tubular wall 31. In the example shown, the upper wall 32 and the lower wall 33 each extend perpendicular to the longitudinal axis X.

[0063] The mold 30 further includes an inner cavity. The inner cavity is bounded by an inner side surface 34 of the mold 30. The side surface 34 is formed by the tubular wall 31. In other words, the side surface 34 is the inner surface of the tubular wall 31 of the mold 30. The side surface 34 is formed by the inner side surface 34 of the mold 30. Figure 5 and 6 The inner side surface 34 of the mould 30 is axisymmetrical about the longitudinal axis X. The side surface 34 extends along the longitudinal axis X to a height Hf greater than the height Ha of each blade 10. The height Hf of the side surface 34 of the mould 30 is between 150 mm and 2000 mm.

[0064] The side surface 34 defines a plurality of sections 34i perpendicular to the longitudinal axis X. Figure 6One of the segments 34i of the side surface 34 is shown. Each segment 34i of the side surface 34 of the mold 30 extends in a plane perpendicular to the longitudinal axis X. Therefore, each segment 34i has a circular shape centered on the longitudinal axis X. Each segment 34i of the side surface 34 has a radius Rf s The radius Rf of each section 34i of the side surface 34 of the mold 30 is s is defined as the distance separating the side surface 34 from the longitudinal axis X in a plane perpendicular to the corresponding longitudinal axis X of the segment 34i. The radius Rf of each segment 34i of the side surface 34 of the mold 30 is s Between 150mm and 1500mm.

[0065] It is worth noting that, according to the first embodiment, the side surface 34 of the mold 30 is generally a cylinder of revolution about the longitudinal axis X. In other words, the radius Rf of each segment 34i of the side surface 34 is s are the same.

[0066] The side surface 34 of the mold 30 is such that for each segment 34i, the height Hf of the side surface 34 is equal to the radius Rf of the segment 34i. s The ratio is less than or equal to 2.0. The side surface 34 of the mold 30 may be such that for each segment 34i, the ratio of the height Hf of the side surface 34 to the radius Rfs of the segment 34i is between 0.5 and 1.5, preferably between 0.75 and 1.25, and more preferably equal to 1.0.

[0067] The inner cavity of the mold 30 is further defined by an inner lower surface 36 of the mold 30 and an inner upper surface 35 of the mold 30. The lower surface 36 and the upper surface 35 are formed by the lower wall 33 and the upper wall 32, respectively. In other words, the lower surface 36 and the upper surface 35 are the inner surfaces of the lower wall 33 and the upper wall 32, respectively. The lower surface 36 and the upper surface 35 are connected to the lower end and the upper end of the side surface 34, respectively. In the illustrated example, the lower surface 36 and the upper surface 35 are preferably each perpendicular to the longitudinal axis X. Moreover, here, the lower surface 36 and the upper surface 35 of the mold 30 are axisymmetric about the longitudinal axis X.

[0068] The production method 100 comprises a second step 120. The second step 120 comprises positioning the mould 30 such that the longitudinal axis X is aligned with the gravitational field g. Thus, the mould 30 is positioned such that the longitudinal axis X extends vertically.

[0069] The production method 100 comprises a third step 130. The third step 130 comprises rotating the mould 30 about the longitudinal axis X at a rotation speed ω comprised between 200 and 800 rpm.

[0070] The production method 100 comprises a fourth step 140. The fourth step 140 comprises pouring material into the internal cavity of the mold 30 so as to form, by centrifugation, a tubular part 20 extending along the longitudinal axis X. The tubular part 20 obtained is also Figure 5 and 6 Visible in.

[0071] The tubular member 20 extends longitudinally between the lower and upper ends to a height Hp that coincides with the height Hf of the side surface 34 of the mold 30. Furthermore, the tubular member 20 has an outer surface 23 that coincides with the side surface 34 of the mold 30. The outer surface 23 of the tubular member 20 is axisymmetrical about the longitudinal axis X.

[0072] The tubular component 20 defines a plurality of segments 20i perpendicular to the longitudinal axis X. Each segment 20i of the tubular component 20 extends in a plane perpendicular to the longitudinal axis X. Each segment 20i of the tubular component 20 is associated with a corresponding segment 34i of the side surface 34 of the mold 30 located at the same longitudinal position. Therefore, the outer surface 23 of the tubular component 20 has a circular shape centered on the longitudinal axis X in each segment 20i of the tubular component 20. In other words, each segment 20i of the tubular component 20 has a radius Rf with respect to the corresponding segment 34i of the side surface 34 of the mold 30. s Coincident outer radius Rep s The outer radius Rep of each section 20i of the tubular member 20 is s is defined as the distance separating the outer surface 23 of the tubular member 20 from the longitudinal axis X in a plane perpendicular to the corresponding longitudinal axis X of the segment 20i. According to the first embodiment, the outer radius Rep of each segment 20i of the tubular member 20 is s are the same.

[0073] In addition, due to the rotation speed ω of the mold 30 around the longitudinal axis X and the height Hf of the side surface 34 and the radius Rf of each segment 34i s The tubular member 20 has an inner surface 24 which substantially has the shape of a truncated cone around the longitudinal axis X. Therefore, the inner surface 24 of the tubular member 20 has a circular shape centered on the longitudinal axis X in each section 20i of the tubular member 20. Each section 20i of the tubular member 20 has an inner radius Rip s The inner radius Rip of each section 20i of the tubular member 20 is s It may be defined as the distance separating the inner surface 24 of the tubular member 20 from the longitudinal axis X in a plane perpendicular to the corresponding longitudinal axis X of the segment 20i.

[0074] The inner surface 24 of the tubular member 20 has a truncated cone shape having a radius at the apex of γ=g / (ω 2(Re0-e t )) defined by the half-width, where

[0075] g is the acceleration due to gravity;

[0076] ω is the rotational speed of the die 30 about the longitudinal axis X;

[0077] Re0 is the outer radius of the section 20i of the tubular member 20 located at the lower end of the tubular member 20;

[0078] e t is satisfied (e t / (Re0-e t ))≤0.7 theoretical thickness.

[0079] In other words, Figure 5 As can be seen in FIG. 1 , the profile of the inner surface 24 of the tubular part 20 in a section plane including the longitudinal axis X is a straight line segment forming an angle with the longitudinal axis X equal to the half angle γ.

[0080] The inner radius Rip of each segment 20i s According to the relationship Rip s (z) = Rip s (0)+tan(γ)*z evolves linearly along the longitudinal axis X, where

[0081] Rip s (z) is the inner radius of a given segment 20i;

[0082] Rip s (0) is the inner radius of the section 20i of the tubular member 20 located at the lower end of the tubular member 20;

[0083] z is the height of a given section 20 i in the tubular member 20 .

[0084] The inner radius Rip of each segment 20i s According to the relationship Rip s (z) = Rip s (0)+γ*z evolves linearly along the longitudinal axis X.

[0085] The term "functional" used with respect to a portion of the tubular part 20 makes it possible to indicate whether the portion so described is intended for forming one or more blades 10. Thus, the tubular part 20 comprises a functional portion 21 containing a blade 10 having a limited excess thickness in its material (this excess thickness is of the order of millimeters, preferably less than 10 mm, more preferably less than 5 mm). The functional portion 21 of the tubular part 20 has, in a section plane comprising the longitudinal axis X, an outline of a rectangular shape, one of the sides coinciding with the outer surface 23 of the tubular part 20. The tubular part 20 comprises a non-functional portion 22 which does not participate in the formation of the blade 10. The non-functional portion 22 is located radially on the inside relative to the functional portion 21.

[0086] Such a profile of the inner surface 24 of the tubular part 20 allows reducing or even eliminating the amount of material forming the non-functional portion 22 of the tubular part 20. Thus, the method 100 allows reducing the amount of initial material required to obtain a plurality of blades 10. In other words, the method 100 improves the casting rate when manufacturing a plurality of turbine engine blades 10.

[0087] The fourth step 140 further comprises determining the amount of material to be poured into the mold 30 so that the thickness e of each section 20i of the tubular part 20 is s Greater than or equal to satisfy (e t / (Re0-e t ))≤0.7 theoretical thickness e t This makes it possible to ensure that the tubular component 20 is thick enough for the production of the turbine engine blade 10, regardless of the longitudinal position involved on the tubular component 20. Preferably, the thickness e of each section 20i of the tubular component 20 is s The thickness e of each section 20i of the tubular member 20 is substantially equal to the theoretical thickness. s Considered in the radial direction relative to the longitudinal axis X. The thickness e of each segment 20i of the tubular part 20 s The outer radius Rep of the segment 20i is defined as s With inner radius Rip s According to the first embodiment, the thickness e of each segment 20i of the tubular member 20 is s Different from the thickness e of each other segment 20i s .

[0088] Specifically, the thickness e of the section 20i located at the upper end of the tubular member 20 is h Equal to satisfy (e t / (Re0-e t ))≤0.7 theoretical thickness e t , where Re0 is the outer radius of the section 20i of the tubular member 20 located at the lower end of the tubular member 20.

[0089] Furthermore, for each segment 20i of the tubular component 20, the functional portion 21 of the tubular component 20 has a thickness in a radial direction relative to the longitudinal axis X. Here, the thickness of the functional portion 21 is equal to the theoretical thickness e of each segment 20i of the tubular component 20. t .

[0090] Advantageously, the rotation speed of the mould 30 about the longitudinal axis X is between 600 and 800 rpm. Thus, a tubular part 20 is obtained in which the mass of the non-functional part 22 is less than or equal to 5% relative to the mass of the functional part 21 of the tubular part 20 .

[0091] The material poured into the mold 30 is a metal alloy of the γ-TiAl type. This material advantageously has good mechanical resistance at high temperatures and has a low density.

[0092] The fourth step 140 further includes heating the material to a temperature between 1550° C. and 1700° C. so as to be poured into the mold 30. Thus, the material poured into the mold 30 is melted, which facilitates casting.

[0093] The method 100 comprises a fifth step 150. The fifth step 150 comprises producing a plurality of turbine engine blades 10 in the tubular component 20, in particular in the functional portion 21 of the tubular component 20. To this end, the tubular component 20 may be machined. The machining may first comprise eliminating (if necessary) the non-functional portion 22. Then, the machining may comprise forming the blades 10 in the functional portion 21.

[0094] Figure 7 and 8 A mold 30 according to a second embodiment for use in the method 100 as described above is shown. The mold 30 according to the second embodiment differs from the mold 30 according to the first embodiment in that a side surface 34 of the mold 30 has the general shape of a truncated cone of revolution about the longitudinal axis X, the truncated cone having a cross section that decreases in the direction of the gravitational field when the mold 30 is positioned with the longitudinal axis X aligned with the gravitational field.

[0095] Therefore, the radius Rf of each segment 34i of the side surface 34 is s Different from the radius Rf of each other section 34i of the side surface 34 s Specifically, the radius Rf of each segment 34i of the side surface 34 is s It decreases linearly along the longitudinal axis X in the direction of the gravitational field.

[0096] Here, the outer surface 23 of the tubular component 20 also coincides with the side surface 34 of the mold 30. Therefore, the outer surface 23 of the tubular component has the general shape of a truncated cone of revolution about the longitudinal axis X, said truncated cone having a cross section that decreases in the direction of the gravitational field when the mold 30 is positioned with the longitudinal axis X aligned with the gravitational field. Therefore, the outer radius Rep of each segment 20i of the tubular component 20 is s Different from the outer radius Rep of each other section 20i of the tubular member 20 s Specifically, the outer radius Rep of each segment 20i of the tubular member 20 is s It decreases linearly along the longitudinal axis X in the direction of the gravitational field.

[0097] Advantageously, here, the rotation speed of the mold 30 according to the second embodiment about the longitudinal axis X is between 200 and 400 rpm, preferably between 300 and 400 rpm. Such a method 100 makes it possible to obtain a tubular part 20 in which the mass of the non-functional part 22 is less than or equal to 5% relative to the mass of the functional part 21. In addition, such a method 100 advantageously has a low rotation speed of the mold 30, which allows reducing the power required to rotate the mold 30 about the longitudinal axis X and therefore reducing the energy consumption of the method 100.

[0098] In addition, the side surface 34 of the mold 30 has a truncated cone shape having a radius at the vertex of β=g / (ω 2 (Re0-e t )) defined by the half-width, where

[0099] g is the acceleration due to gravity;

[0100] ω is the rotational speed of the die 30 about the longitudinal axis X;

[0101] Re0 is the outer radius of the section 20i located at the lower end of the tubular member 20; and

[0102] e t is satisfied (e t / (Re0-e t ))≤0.7 theoretical thickness.

[0103] Therefore, the half angle β at the vertex of the side surface 34 of the mold 30 is equal to the half angle γ at the vertex of the inner surface 24 of the tubular member 20. Therefore, the thickness e of each section 20i of the tubular member 20 is sis the same, regardless of the longitudinal position of the segment on the tubular part 20. The tubular part thus has a constant radial thickness over its entire height Hf. In the present case, this allows the elimination of non-functional portions 22 of the tubular part 20. In other words, the use of the mould according to the second embodiment allows obtaining a tubular part 20 without any non-functional portions 22. In this case, for each segment, the thickness e of the tubular part 20 is s is equal to the thickness of the functional portion 21, ie, in the present case, equal to the theoretical thickness e t .

[0104] It is also noteworthy that in the second embodiment, the functional portion 21 of the tubular part 20 has, in a section plane including the longitudinal axis X, a profile in the shape of a parallelogram, one of the sides coinciding with the outer surface 23 of the tubular part 20 .

[0105] The tubular wall 31 of the mould also comprises an outer surface 37. The outer surface 37 of the tubular wall 31 advantageously has the shape of a truncated cone. Specifically, according to the example shown, here the outer surface 37 of the tubular wall 31 has the shape of a truncated cone, wherein the half angle at the vertex is equal to the half angle at the vertex β of the side surface 34. This makes it possible to obtain a constant heat extraction over the entire height of the mould.

[0106] Fig. 9 and 10 30 according to the first embodiment and the variants of the mold 30 according to the second embodiment are respectively represented. In each of these variants, the side surface 34 of the mold 30 includes a first protrusion and a second protrusion, each of which is formed annularly around the longitudinal axis X. Such an annular protrusion makes it possible to partially preform the turbine engine blade 10 in an annular portion. Here, the first annular protrusion 38 and the second protrusion are each annular grooves formed in the side surface 34 of the mold 30. The first annular protrusion 38 is located near the lower end of the side surface 34. The second annular protrusion 37 is located near the upper outer portion of the side surface 34. Here, the first annular protrusion 38 is intended for preforming the root of each blade 10, and the second annular protrusion 37 is intended for preforming the tip of each blade 10.

Claims

1. A method (100) for producing a plurality of turbine engine blades (10), the plurality of turbine engine blades (10) having a height (Ha), the method comprising: - providing a mould (30) comprising an internal cavity, the internal cavity being defined by a longitudinal axis (X) of the mould An inner side surface (34) is defined by an axisymmetric side surface (34), the side surface (34) extending along the longitudinal axis (X) to a height (Hf) greater than or equal to the height (Ha) of each blade (10), the side surface (34) defining a plurality of segments (34i) perpendicular to the longitudinal axis (X), each segment (34i) of the side surface (34) having a radius (Rf s ), the side surface (34) of the mold (30) is such that for each segment (34i), the height (Hf) of the side surface (34) is equal to the radius (Rf) of the segment (34i). s ) ratio is less than or equal to 2.0; - positioning the mould (30) such that the longitudinal axis (X) is aligned with the gravitational field (g), - rotating the mould (30) about the longitudinal axis (X) at a rotation speed (ω) between 200 and 800 rpm, - Pouring material into said internal cavity of said mould (30) so as to form, by centrifugation, a tubular part (20) extending along said longitudinal axis (X).

2. The method (100) according to the preceding claim, characterized in that The obtained tubular component (20) has a plurality of sections (20i) perpendicular to the longitudinal axis (X), the method further comprising: determining the amount of material to be poured into the mold (30) so that the thickness (e) of each section (20i) of the tubular component (20) is s ) is greater than or equal to satisfy (e t / (Re0-e t ))≤0.7 theoretical thickness (e t ), wherein Re0 is the outer radius of the section of the tubular member (20) located at the lower end of the tubular member (20).

3. A method according to any preceding claim, characterised in that The internal cavity of the mold (30) is defined by an internal lower surface (36) of the mold (30) and an internal upper surface (35) of the mold, wherein the lower surface (36) and the upper surface (35) are respectively connected to the lower end and the upper end of the side surface (34), and the lower surface (36) and the upper surface (35) are preferably each perpendicular to the longitudinal axis (X).

4. The method (100) according to any of the preceding claims, characterized in that The side surface (34) of the mold (30) is generally a cylinder of rotation about the longitudinal axis (X), and wherein the rotation speed (ω) of the mold (30) about the longitudinal axis (X) is between 600 rpm and 800 rpm.

5. The method (100) according to any one of claims 1 to 3, characterized in that: The side surface (34) of the mold (30) has the general shape of a truncated cone rotated about the longitudinal axis (X), the truncated cone having a cross-section that decreases in the direction of the gravitational field (g) when the mold (30) is positioned so that the longitudinal axis (X) is aligned with the gravitational field (g), and wherein the rotational speed (ω) of the mold (30) about the longitudinal axis (X) is between 200 rpm and 400 rpm.

6. The method (100) according to the preceding claim, characterized in that The side surface (34) of the mold (30) has a truncated cone shape, and the truncated cone has a radius at the vertex of β=g / (ω 2 (Re0-e t )) defined by the half angle (β), where g is the acceleration due to gravity; ω is the rotational speed of the die about the longitudinal axis; Re0 is the outer radius of the section of the tubular member perpendicular to the longitudinal axis and located at the lower end of the tubular member; e t is satisfied (e t / (Re0-e t ))≤theoretical thickness of 0.

7.

7. The method (100) according to any of the preceding claims, characterized in that The side surface (34) of the mold (30) comprises at least one protrusion (37; 38) formed annularly around the longitudinal axis (X).

8. The method (100) according to any of the preceding claims, characterized in that The material poured into the mold (30) is a metal alloy, preferably titanium aluminide (TiAl), more preferably a γ-TiAl alloy.

9. The method (100) according to any of the preceding claims, characterized in that The material poured into the mould (30) is an alloy of the γ-TiAl type, the method further comprising heating the material to a temperature between 1550° C. and 1700° C. in order to pour it into the mould (30).

10. The method (100) of any preceding claim, further comprising machining the tubular member (20) to form the plurality of turbine engine blades (10).

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