BE1027837B1 - PROCESS FOR MANUFACTURING A COMPRESSOR VANE - Google Patents

Abstract

The invention relates to a method of manufacturing a turbine engine compressor blade, comprising the following steps: determining the deformation and / or residual stresses of the part during and after each operation of the manufacturing process, the operations comprising a forging operation and possibly one of the following operations: burr cutting, cooling and / or heat treatment; integration of the deformation and / or the residual stresses thus determined for the parameterization of the forging operation, in particular according to a comparison between the deformation and / or the determined stresses and a deformation and / or nominal residual stresses ; and carrying out the forging operation thus configured. The invention also relates to a compressor comprising a blade made at least in part by the manufacturing method of the invention.

Description

METHOD OF MANUFACTURING A COMPRESSOR VANE Description Technical Field The invention relates to a method of manufacturing a compressor vane. In particular, the invention aims to configure a forging operation. More particularly, the invention relates to the dimensioning of a die intended for the manufacture of the blade.

BACKGROUND ART Forging compressor blades may exhibit residual stresses and may deform upon cooling. Thus, despite manufacturing operations which initially aim to obtain the blade in its nominal dimensions, there remains a certain variability in the final dimensions of the blades.

In order to obtain compressor vanes with nominal dimensions, it is sometimes necessary to straighten the vane after its forging operation. This straightening can be done in a more or less controlled manner and needs to be supplemented by non-destructive testing, or even annealing, to ensure that the straightening has not affected the mechanical properties of the blade.

These operations represent a cost and a need for labor, and are sources of waste.

Summary of the invention Technical problem The object of the invention is to overcome at least one of the drawbacks of the method described above. More particularly, the present invention aims to make it possible to obtain parts of desired dimensions without requiring any additional operation.

Technical solution The subject of the invention is a method for manufacturing a turbine engine compressor blade, comprising the following steps: determining the deformation and / or residual stresses of the part during and after each operation of the manufacturing process, the operations comprising a forging operation and optionally one of the following operations: burr cutting, cooling and / or heat treatment; the integration of the deformation and / or the residual stresses thus determined for the parameterization of the forging operation, in particular according to a comparison between the deformation and / or the determined residual stresses and a deformation and / or nominal residual stresses; and carrying out the forging operation thus configured.

The determination of the deformation and the residual stresses is carried out by numerical simulation.

Given the number of variables taken into account, it is impossible to make these predictions without the assistance of appropriate computer resources.

One will choose in particular the simulation by finite elements with - this is only one example - a thermal mesh of the type C3D8 and a mechanical mesh of the type C3D20. According to an advantageous embodiment of the invention, the parameterization comprises the sizing of a manufacturing tool, in particular the sizing of the die used for the forging operation.

According to an advantageous embodiment of the invention, the deformation and / or the residual stresses of the part are determined when the die is at the nominal dimensions of the part, then the dimensions of the die are corrected as a function of the deformation and / or of the residual stresses thus determined.

According to an advantageous embodiment of the invention, the dimensioning of the matrix is carried out by iterations.

According to an advantageous embodiment of the invention, the deformation comprises the twisting of the blade about at least one axis of the blade.

This torsional deformation can be critical for a blade, in particular the sweep angle of which must correspond as well as possible to the nominal values to properly direct the flow of the air flow.

According to an advantageous embodiment of the invention, the blade comprises a blade and a root of thickness much greater than that of the blade, the determination of the deformation and of the residual stresses consisting of the deformation and of the residual stresses of the blade.

Indeed, it is possible to carry out the method with less computer resources when considering the massive part of the blade (the foot) as invariable limiting conditions in dimension and in thermal, and thus by limiting the calculation only to the blade, much thinner than the root, and therefore deformable. According to an advantageous embodiment of the invention, the determination of the deformation and / or of the residual stresses takes into account the rheological properties of the material constituting the blade, these properties comprising in particular: the relaxed and non-relaxed elastic moduli as well as the times relaxation, Poisson's ratio, coefficient of thermal expansion, coefficient of humidity expansion, thermal conductivity. According to an advantageous embodiment of the invention, the forging operation is a precision forging operation. By "precision forging" is meant a forging operation that is precise enough to achieve the dimensions and surface condition required for the finished part, without the need for subsequent rework by machining or grinding.

According to an advantageous embodiment of the invention, the precision forging operation is integrated into a forging range comprising, before said precision forging operation, an extrusion operation of a round rough, followed by an operation of repression.

According to an advantageous embodiment of the invention, the blade is made of a forgeable alloy, in particular a titanium or nickel alloy.

The invention also relates to an aircraft turbojet compressor comprising at least one rotor or stator blade produced at least in part by the manufacturing method according to one of the embodiments described above.

Advantages of the invention The measures of the invention are advantageous in that they make it possible to eliminate the step of straightening out non-conforming blades. During the industrialization of a new blade, the process of the invention makes it possible to obtain blades directly conforming to the nominal dimensions without requiring experimentation on long and expensive forging dies. Industrialization is therefore cheaper and faster.

Brief description of the drawings

FIG. 1 illustrates a compressor blade obtained by the method according to the invention; FIG. 2 represents the method of the invention. Description of an Embodiment Figure 1 shows a compressor blade 1. The vane 1 can be a stator vane or a rotor vane of an axial turbomachine. It can be made of a titanium alloy of the TAGV type, of inconel or any other nickel alloy or any other alloy suitable for undergoing a forging operation. Dimensions and thicknesses are not shown to scale and the vane is only shown schematically.

In this example, vane 1 has a foot 2 designed to assemble vane 1 to a ferrule or drum. In this example, foot 2 has a dovetail for this purpose. A blade 4 extends mainly in a longitudinal direction A which can substantially be a radial direction of the turbomachine. The direction indicated as B is substantially parallel to the chord of the vane.

The blade 4 has an intrados side 5 and an extrados side 6 which guide the air flow.

When cooling after a forging operation of the blade 4, the latter can be deformed. An elastic return at the forge outlet, or non-homogeneous cooling can generate a torsion T around the axis A and / or a torsion U around the axis B. This torsion implies that the blade no longer conforms to its nominal geometry.

The invention aims to anticipate this twist in order to manufacture a blade which, despite its deformation, will suit the desired dimensions.

Foot 2 is more massive than blade 4, the thickness of foot 2 (measured radially, that is to say vertically in Figure 1) can be 5 to 30 times greater than the thickness of blade 4 (measured circumferentially, that is to say horizontally in Figure 1).

Thus, the root 2 deforms negligibly compared to the deformation of the blade 4.

Whether from a mechanical point of view or from a thermal point of view, the foot 2 therefore acts as stable boundary conditions over time.

By choosing to ignore this tiny deformation of the foot and the tiny residual stresses resulting therefrom, it is therefore possible to save computer resources during the simulation: the part to be simulated is smaller; the mesh is more homogeneous on the blade 4 alone than on the entire blade 1; the variations in dimensions and in residual stresses are continuous on the blade 4. FIG. 2 describes a diagram of the method according to the invention.

During the design of the blade (step 100), the geometry of the blade, its nominal dimensions and its nominal mechanical properties (including the admissible residual stresses) are defined. In an industrialization step 200, the manufacturing parameters are determined as a function of the dimensions and of the nominal residual stresses.

For example a form of matrix very close to the nominal dimensions can be chosen.

The manufacturing parameters determined here may also include the machine parameters during the forging operation: speed, temperature, die material, etc.

In step 300, a calculation algorithm is performed to determine, from the manufacturing parameters of step 200, the consequences on the part obtained.

Numerical simulation makes it possible to obtain these results, in particular by taking into account the rheological properties of the material making up the blade.

The calculated dimensions and mechanical properties 400 are compared, in a step 500, with the nominal mechanical dimensions and properties.

If there is a deviation greater than a certain tolerance threshold, the manufacturing parameters are modified in a step 600. For example, if it is calculated that the obtained vane has been deformed in torsion by an angle greater than a given threshold angle, the corresponding dimensions of the matrix are adjusted accordingly.

After modification of the manufacturing parameters, the algorithm is performed again, and the loop is repeated until the deviation becomes less than the given threshold.

Once this threshold is reached, the manufacturing parameters are maintained (step 700).

Alternatively, the iterations can be of a given predefined number without convergence criterion.

The geometry of the matrix thus determined can be confirmed by experimental tests.

This modeling avoids the multiplication of actual prototyping tests with different manufacturing parameters or trial and error with the use of several dies, since in practice only one or two prototypes will be made.

The algorithm carried out in step 300 includes a certain number of calculation steps, and can take into account several physical phenomena, linked to the various successive manufacturing operations (extrusion, upsetting, precision forging, etc.).

Claims (11)

Claims 1. A method of manufacturing a turbine engine compressor blade, comprising the following steps: - determining the deformation and / or residual stresses of the part during and after each operation of the manufacturing process, the operations comprising an operation of forging and optionally one of the following operations: burr cutting, cooling and / or heat treatment; - the integration of the deformation and / or the residual stresses thus determined for the parameterization of the forging operation, in particular according to a comparison between the deformation and / or the determined residual stresses and a deformation and / or nominal residual stresses; and - carrying out the forging operation thus configured. 2. Method according to claim 1, characterized in that the parameterization comprises the sizing of a manufacturing tool, in particular the sizing of the die used for the forging operation. 3. Method according to claim 2, characterized in that the deformation and / or the residual stresses of the part are determined when the die is at the nominal dimensions of the part, then the dimensions of the die are corrected as a function of the deformation and / or the residual stresses thus determined. 4. Method according to claim 3, characterized in that the dimensioning of the matrix is carried out by iterations. 5. Method according to one of claims 1 to 4, characterized in that the deformation comprises the twisting of the blade about at least one axis of the blade. 6. Method according to one of claims 1 to 5, characterized in that the blade comprises a blade and a root of thickness much greater than that of the blade, the determination of the deformation and of the residual stresses consisting of the deformation. and the residual stresses of the blade. 7. Method according to one of claims 1 to 6, characterized in that the determination of the deformation and / or of the residual stresses takes into account the rheological properties of the material constituting the blade, these properties comprising in particular: the relaxed elastic moduli and no- relaxed as well as the associated relaxation times, Poisson's ratios, coefficient of thermal expansion, coefficient of humidity expansion, thermal conductivity. 8. Method according to one of claims 1 to 7, characterized in that the forging operation is a precision forging operation. 9. The method of claim 8, characterized in that the precision forging operation is integrated into a range of forging comprising, before said precision forging operation, an extrusion operation of a round rough, followed by a pushback operation. 10. Method according to one of claims 1 to 9, characterized in that the blade is made of a forgeable alloy, in particular a titanium or nickel alloy. 11. Aircraft turbojet compressor, characterized in that it comprises at least one rotor or stator blade produced at least in part by the manufacturing process according to one of claims 1 to 10.