FR3071077A1 - 3D MODELING METHOD FOR FIBRING A METAL PIECE - Google Patents

Abstract

The invention relates to a method for 3D modeling of a fibering of a metal part, the formation of said part comprising at least one forging step from a metal billet, said method comprising the following steps: a 3D fiber drawing of the metal billet, the fiberization being oriented in a longitudinal direction of said billet; - modeling of a range of forging and / or machining; - numerical simulation of forging and / or machining stage (s) by applying the modeling of the forging and / or machining range to the 3D modeling of the billet fiberization, generating a deformation of the fiber drawing - generation of 3D modeling of the fiber drawing of the forged metal part; and characterized in that during the step of modeling the 3D fiberizing of the metal billet, the fiberizing is modeled by a plurality of coaxial cylinders extending in a longitudinal direction of said billet.

Description

3D modeling process for fiber drawing of a metal part

GENERAL TECHNICAL AREA

The invention relates to the field of the identification of defects in metallic industrial parts obtained by forging, in particular in the field of aeronautics.

More specifically, the invention relates to a 3D modeling method of the fiber drawing of a metal part.

STATE OF THE ART

Knowledge and control of fiber drawing are essential elements during the design of a turbomachine part to guarantee its mechanical strength or its ultrasonic controllability in the volume of the part, the defects being in the volume of the part, including included on the surface.

Initially, the raw casting metal (in the form of an ingot, a bar, a billet ...) consists of solidification grains. Under the action of forging operations, the grains are broken and cells or new grains appear. These microstructures, as well as the inclusions, are then stretched in the direction of the deformation. We then find an elongated structure, materialized by a network of fibers, which defines fiberizing. Wrought semi-finished products such as bars generally have unidirectional fiberizing. Forging, normally occurring after wrought operations, will modify the fiber drawing and its orientation, and adapt it to the geometry of the final part that one wishes to obtain.

Fiber drawing is therefore a concept which translates the anisotropy of the mechanical properties of a part and makes it possible to visualize the real flow (deformation) of the material during forging operations.

For example, for a Titanium part, fiber drawing is the preferred orientation of its crystal lattice (before any deformation in hot forging range).

For a nickel-based part, fiber drawing is the alignment of the precipitates or alloying elements which will orient themselves according to the flow of the material.

When observing metal parts obtained by forging, defects can be identified, for example of the partridge eye type (or tree rings), reflecting a disorientation of certain fibers during forging.

The mere visual identification of this type of defect does not allow them to be characterized, so these defects can be acceptable depending on their nature.

In particular, these faults can come from:

- fiber drawing accidents which will strongly impact the static characteristics and the fatigue strength of the final part. Such faults can originate from an unstable forging range. Defects of this nature are therefore unacceptable;

- machining. In this case, the parts are forged in excess thickness and are subsequently machined in order to respect determined dimensions (the final dimensions of the part). It is during this machining that fibers are exposed, forming defects in the shape of a partridge's eye type. Defects of this nature are most often acceptable.

To determine the source of these defects, and to demonstrate in particular that these result from the machining of said part and that they are therefore possibly acceptable defects, a solution is therefore to model the fiber drawing and observe its deformation during the forging process according to one or more cutting planes of said part.

In known manner, for forged revolution parts (for example compressor or turbine parts such as discs or shafts), the fiber drawing is modeled by a 2D grid representing the network of fibers.

During the forging of the part of revolution, the assumption being made that the flow of the material being done only in one plane, the 2D modeling of the fiber drawing makes it possible to visualize the fiber drawing after deformation according to the corresponding cutting plane.

Forging simulation software, such as FORGE®, generally used to model the ranges of forges make it possible to model the fiber drawing in axisymmetric or non-axisymmetric parts using a 2D grid (see Figure IA).

In the case of a part called simple geometry, this grid is not caused to deform (GND).

In the case of a part called of complex geometry (in particular not axisymmetric), this grid can be deformed (GD) according to the three directions of space. It is therefore no longer possible to pass a cutting plane on which the fiber drawing can be observed after deformation (see FIG. 1B).

Consequently, in the case of parts for which the flows of the matter are done according to the three directions of space, it is not possible to model the fiber drawing according to a single plane chosen arbitrarily at the beginning of the deformation. A designer of the part, user of the simulation software, will therefore not be able to observe the fiber drawing of the part according to a cutting plane which he will have chosen taking into account the deformations undergone by the starting plane.

Thus, as illustrated in FIG. 1B, when a cut is made parallel to the X axis (longitudinal axis) of a complex part 10, it is not possible to visualize the fiber drawing at certain points (A and B). Indeed, these points correspond to a part of the deformed 2D grid (GD), and no longer being in the cutting plane, it is therefore not possible to visualize the deformation of said grid in the cutting plane.

There is therefore a need to improve the fiberizing modeling methods, in order to be able to visualize with more flexibility the fiberizing of a forged part and thus make it possible to make the characterization of the defects of the forged parts more reliable, particularly in the case of parts to complex geometry.

PRESENTATION OF THE INVENTION

The invention implements a characterization of the defects of a metal part obtained by forging, by a 3D modeling of the fiberizing of said forged part.

The invention thus proposes a method for 3D modeling of a fiber drawing of a metal part, the formation of said part comprising at least one step of forging from a metal billet, said method comprising the following steps:

- Modeling of a 3D fiber drawing of the metal billet, the fiber drawing being oriented in a longitudinal direction of said billet;

- modeling of a range of forging and / or machining;

- numerical simulation of forging and / or machining step (s) by applying the modeling of the forging and / or machining range to the 3D modeling of the billet fiber drawing, generating a fiber deformation; and

- generation of a 3D modeling of the fiber drawing of the forged metal part.

During the step of modeling the 3D fiber drawing of the metal billet, the fiber drawing is modeled by a plurality of coaxial cylinders extending in a longitudinal direction of said billet.

The invention makes it possible to reliably determine whether a defect is acceptable and linked to the forging process on parts of complex geometry.

The invention thus makes it possible to guarantee the mechanical strength or the ultrasonic controllability of a forge with complex geometry.

The invention can include the following features:

- the metal part has an asymmetrical geometry;

- The method further comprises a step of detecting faults identifying the deformations of the part corresponding to given faults;

- the distance between two adjoining cylinders is approximately 5 millimeters;

- the metal billet comprises titanium, nickel, aluminum or steel;

- the metal part is a fan blade;

- Said fiber drawing is modeled by a plurality of coaxial cylinders on the first millimeters of peripheral thickness of the billet;

- the fiber drawing is modeled by a plurality of coaxial cylinders on a peripheral thickness of the billet less than approximately 6 millimeters, and in which the distance between 2 contiguous cylinders is approximately 1 millimeter.

The invention also relates to a computer program product, comprising code instructions for implementing a method comprising:

- Modeling of a 3D fiber drawing of a metal billet, the fiber drawing being oriented in a longitudinal direction of said billet, and said fiber drawing being modeled by a plurality of coaxial cylinders and extending in a longitudinal direction of said billet and;

- modeling of a range of forging and / or machining to form a metal part from the metal billet;

- numerical simulation of forging and / or machining step (s) by applying the modeling of the forging and / or machining range to the 3D modeling of the billet fiber drawing, generating a fiber deformation; and

- generation of a 3D modeling of the fiber drawing of the forged metal part;

when the latter is implemented by processing means of a processing unit.

PRESENTATION OF THE FIGURES

Other characteristics, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and not limiting, and which should be read with reference to the appended drawings, in which:

- Figures IA and IB, already presented, illustrate a modeling of a 2D fiber drawing of a non-axisymmetric forged part, according to the state of the art, respectively before and after deformation;

- Figure 2A illustrates a metal bar;

- Figure 2B illustrates an initial fiber drawing of a bar in a longitudinal section;

- Figure 3 illustrates some steps of an embodiment according to the invention;

- Figure 4 illustrates the modeling of a fiber drawing of a bar in 3D according to an embodiment according to the invention;

- Figure 5A illustrates the modeling of a 3D fiber drawing of a forged part according to an embodiment according to the invention;

- Figure 5B illustrates a fiber drawing of a forged part in correspondence with said modeling of the part illustrated in Figure 5A;

- Figure 6 illustrates the modeling of a 3D fiber drawing of a forged part according to an embodiment according to the invention, as well as the modeling of a 2D fiber drawing according to the state of the art.

DETAILED DESCRIPTION

The 3D modeling process can be applied to different stages of manufacturing a forged metal part 10.

The parts 10 on which the methods described can be implemented are preferably intended for aeronautics. These are, for example, fan blades, turbines, rotor discs, or even landing gear parts.

Said part 10 generally comprises a complex geometry, in particular non-axisymmetric.

FIG. 2A illustrates a bar or billet 20, from which a part is preferably forged. The billet is the starting metal which generally is a cylinder.

The dimensions of a bar 20, for example a fan blade, will typically range from 40 to 80 millimeters approximately. The dimensions of a billet 20 for disc or tree will range from 150 to 400 millimeters approximately.

The billet 20 can be composed of titanium, nickel, aluminum or steel. Most of the time, the billet from which the part is forged has a fiber drawing composed of a network of fibers. Indeed, the billet could have undergone operations such as rolling, forging or spinning, which give it a fiber drawing in a unidirectional and longitudinal direction, parallel to the axis X, of the billet 20.

Thus, the section along a longitudinal plane of a billet 20 before forging makes it possible to view the fibers and their unidirectional orientations as illustrated in FIG. 2B.

FIG. 3 represents certain steps of an embodiment of a fiberizing modeling method.

A calculation unit 50 is provided to perform the computer processing necessary for the implementation of the fiberization modeling method according to the embodiment. Said unit includes processing means such as a microprocessor μ and a memory.

In a step 110, the fibering of the billet 20 is modeled.

It is assumed that the fiber drawing of the bars or billets 20 used in the context of the manufacture of parts for a turbomachine is oriented in the direction of a direction parallel to the axis X of the bar or the billet.

The plurality of billet fibers 20 can be modeled by a plurality of cylinders 30 of distinct cylindrical surfaces. The cylinders are preferably coaxial (see FIG. 4) and extend in a longitudinal direction of said billet 20. Preferably, the cylinders have the same axis X as the billet 20.

This gives a 3D modeling of the fibering of the billet 20.

The number of cylinders 30, the dimensions of their bases and the distance between two contiguous cylinders are determined empirically in order to have a sufficient quantity of information, but acceptable by the processing capacities of an element modeling software. finished. The distances between the surfaces of two contiguous cylinders are preferably equivalent in the plurality of cylinders 30.

In the case where it is desired to model the fiber drawing on the whole of the billet 20, the distance between two contiguous cylinders is preferably about 5 millimeters.

In a particular embodiment, for example in the context of the modeling of certain metal parts such as fan blades, it is possible to apply the modeling to a single part of the part, such as a blade root . Thus, in this example, in the context of looking for partridge eye type defects, we can model the fiber drawing only on the periphery of the billet 20. Consequently, we only model about the first 6 millimeters of thickness , with a distance between two adjoining cylinders of, for example, about 1 millimeter.

In a step 120, the forging and / or machining range applied to the billet 20 is modeled. The modeling parameters include in a non-exhaustive manner the starting geometry, the geometry throughout the deformations, the final geometry, temperatures applied to bar 20, tool movements, heat exchanges, multiple upsetting, crushing, stamping ...

In a step 130, a step of numerical simulation of the forging process is carried out. The modeling data for the forging and / or machining range determined in step 120 described above are applied to the 3D modeling of the fiber drawing of the billet 20. The digital simulation makes it possible to visualize the deformations undergone by the fiber drawing of the room.

Thus, the cylinders 30 are deformed following the flow of the material during the modeling of the forging.

In a step 140, the digital simulation of forging will therefore generate a 3D modeling of the final part 10, modeled, obtained after forging.

Steps 120 to 140 can be implemented by a finite element software dedicated to the shaping of materials such as FORGE®, DEFORM ™, QFORM ©, SIMUFACT © ... These software allow modeling the shaping of materials with elastoplastic or elasto-viscoplastic behavior in large deformations.

A user of simulation software can then view the modeled part 10 according to any cutting plane of his choice and observe the fiber drawing.

Said user can therefore categorize the deformations of the fiber drawing obtained during the forging of the part 10. The user can therefore identify the defects of the part 10 from a given forging / machining range. Thus, by comparison with the fiber drawing model of the modeled part 10, it can be determined whether a defect observed on a forged part corresponding to the modeled part results from the forging process or from a forging accident.

The 3D modeling process described therefore makes it easy to determine and make reliable the categorization of the defects observed on the surface of a forged part.

FIG. 5A represents such a part modeled according to an embodiment of the method and makes it possible to observe, according to a cutting plane, the fiber drawing of the forged part. In particular, said process makes it possible to observe that the fiber drawing obtained by the forging and / or machining range generates a defect of the partridge eye type 40.

In order to guarantee that the modeled fiber drawing corresponds to the fiber observed on the part, a series of parts can be specially produced. The production range is adapted so that a part is cut for analysis after each step of the forging / machining range as illustrated in FIG. 5B. We can thus observe and verify the fiber-drawing simulation process of the part.

The modeling of the fiber drawing as presented in the method described above makes it possible to observe the fiber drawing on forgings with complex geometry according to any cutting plane chosen by a user of modeling software. Thus, unlike axisymmetric parts for which the modeling of the range is carried out in 2D and for which the cutting plane must correspond to the 2D plane of the modeling, the fiber drawing can therefore be observed according to the determined cutting plane.

Figure 6 shows a section along a longitudinal plane of a part

10. Also, said figure represents more particularly the fiber drawing modeled in 2D by the deformed grid (GD) modeled according to known methods and the fiber drawing modeled in 3D (F3D) according to an embodiment of the method. It is thus observed that it is impossible to determine the fiber drawing from the deformed grid (GD) since it is not contained in the cutting plane unlike 3D fiber drawing (F3D) which can be cut according to any plan.

Claims (9)

claims 1. A method of 3D modeling of a fiber drawing of a metal part (10), the formation of said part comprising at least one step of forging from a metal billet (20), said method comprising the following steps: - Modeling of a 3D fiber drawing of the metal billet (20), the fiber drawing being oriented in a longitudinal direction of said billet; - modeling of a range of forging and / or machining; - numerical simulation of forging and / or machining step (s) by applying the modeling of the forging and / or machining range to the 3D modeling of the drawing of the billet (20), generating a deformation of the drawing ; and - Generation of a 3D modeling of the fiber drawing of the metal piece (10) forged, characterized in that during the step of modeling the 3D fiber drawing of the metal billet (20), the fiber drawing is modeled by a plurality of coaxial cylinders (30) extending in a longitudinal direction of said billet (20). 2. Method for 3D modeling of a fiber drawing of a metal part (10) according to the preceding claim, in which the metal part (10) has an asymmetrical geometry. 3. Method for 3D modeling of a fiber drawing of a metal part (10) according to one of the preceding claims, further comprising a step of detecting deformations of the fiber drawing of the part. 4. Method for 3D modeling of a fiber drawing of a metal part (10) according to one of the preceding claims, in which the distance between two contiguous cylinders is approximately 5 millimeters. 5. Method for 3D modeling of a fiber drawing of a metal part (10) according to one of the preceding claims, in which the metal billet (20) comprises titanium, nickel, aluminum or steel . 6. Method for 3D modeling of a fiber drawing of a metal part (10) according to one of the preceding claims, in which the metal part is a fan blade. 7. Method for 3D modeling of a fiber drawing of a metal part (10) according to one of the preceding claims, in which said fiber drawing is modeled by a plurality of coaxial cylinders (30) over the first peripheral millimeters of thickness. the billet (20). 8. Method for 3D modeling of a fiber drawing of a metal part (10) according to the preceding claim, in which the fiber drawing is modeled by a plurality of coaxial cylinders on a peripheral thickness of the billet (20) less than about 6 millimeters , and in which the distance between 2 contiguous cylinders is approximately 1 millimeter. 9. Product computer program, comprising code instructions for implementing a method comprising steps of: - Modeling of a 3D fiber drawing of a metal billet (20), the fiber drawing being oriented in a longitudinal direction of said billet, and said fiber drawing being modeled by a plurality of coaxial cylinders (30) and extending in a longitudinal direction of said billet (20) and; - modeling of a range of forging and / or machining to form a metal part (10) from the metal billet (20); - numerical simulation of forging and / or machining step (s) by applying the modeling of the forging and / or machining range to the 3D modeling of the drawing of the billet (20), generating a deformation of the drawing ; and - generation of a 3D modeling of the fiber drawing of the forged metal part (10); when the latter is implemented by processing means of a processing unit (50). 1/5