Method for producing a hollow part made of a metal material and use of this method for producing a landing gear rod or beam

Abstract

A method for producing a hollow part (17; 21; 46) made of a metal material, includes preparing a blank (1; 18; 33) of the metal material of the hollow part (17; 21; 46), and at least one sacrificial mandrel (2; 19; 34, 35) made of a material which has a yield stress in the range from −30% to +20% of the yield stress of the material of the blank (1; 18; 33), preferably in the range from −15% to +10%, ideally in the range from −5% to +3%; applying a punch (10) on at least one of the ends of the blank (1; 18; 33) in order to produce the expansion of at least a portion of said blank (1; 18; 33) and to create at least one internal space (12; 20; 36, 37) inside said blank (1; 18; 33); inserting a sacrificial mandrel (2; 19; 34; 35) in said an internal space (12; 20; 37) of the blank (1; 18; 33);crimping the sacrificial mandrel (2; 19; 34, 35) in said blank (1; 18; 33);producing, by co-forging, a simultaneous deformation of said blank (1; 18; 33) and of said sacrificial mandrel (2; 19; 34, 35), with a homothetic ratio K; and performing a machining in order to remove the sacrificial mandrel (2; 19; 34, 35).

Claims

1 to 14. (canceled)

15. A method for producing a hollow part made of a metal material having given yield stresses at given temperatures, the method comprising: preparing a blank having two ends, made up of the metal material of the hollow part, and a sacrificial mandrel made of a material that, at all temperatures at which the various simultaneous deformations of the blank and the sacrificial mandrel, will take place, has a yield stress in the range from −30% to +20% of the yield stress of the material of the blank at the temperatures; applying a punch on one of the ends of the blank in order to produce the expansion of at least a portion of the blank and to create an internal space inside the blank; inserting the sacrificial mandrel in the internal space of the blank; crimping the sacrificial mandrel in the blank; producing, by co-forging, a simultaneous deformation of the blank and the sacrificial mandrel, with a homothetic ratio K; and performing a machining in order to remove the sacrificial mandrel and impart a final configuration to the internal space of the part.

16. The method according to claim 15, wherein the simultaneous deformations of the blank and the sacrificial mandrel are done, for a deviation of the yield stresses of −30% to +20%, with a deviation relative to the strict homothety from −15% to +10% with, for a deviation in the yield stresses from −15% to +10%, a deviation relative to the strict homothety from −7% to +5%, and for a deviation in the yield stresses from −5% to +3%, a deviation relative to the strict homothety from −2.5% to +1.5%.

17. The method according to claim 15, wherein at least one other simultaneous deformation of the blank and the sacrificial mandrel is produced before the machining.

18. The method according to claim 17, wherein the at least one other simultaneous deformation comprises a die stamping.

19. The method according to claim 17, wherein the at least one other simultaneous deformation comprises a drawing.

20. The method according to claim 15, wherein the blank has a symmetry of revolution.

21. The method according to claim 20, wherein the blank is cylindrical.

22. The method according to claim 15, wherein the sacrificial mandrel is cylindrical.

23. The method according to claim 15, wherein the blank is heated before the application of the punch.

24. The method according to claim 15, wherein before applying of the punch, the blank is inserted in the container of a press, a space being arranged between the blank and the inner wall of the container to allow the expansion of the blank.

25. The method according to claim 15, wherein the punch and the sacrificial mandrel are made up of the same part.

26. The method according to claim 15, wherein the blank is a Ti alloy of type Ti-10-2-3, the sacrificial mandrels are each made from a steel chosen from steels of types E28-3 and E24-2.

27. The method according to claim 15, wherein the blank is not expanded over its entire length and the sacrificial mandrel does not extend over the entire length of the blank, and the blank is turned over, the punch is applied on the other end of the blank, and the expansion of another portion of the blank is done by creating another internal space of the blank, and another sacrificial mandrel is inserted into the other internal space of the blank.

28. The method according to claim 15, wherein the sacrificial mandrel made of a material that, at all temperatures at which the various simultaneous deformations of the blank and the sacrificial mandrel, will take place, has a yield stress in the range from −15% to +10% of the yield stress of the material of the blank at the temperatures.

29. The method according to claim 28, wherein the sacrificial mandrel made of a material that, at all temperatures at which the various simultaneous deformations of the blank and the sacrificial mandrel, will take place, has a yield stress in the range from −5% to +3% of the yield stress of the material of the blank at the temperatures.

30. A method of producing a landing gear rod comprising: performing the method of claim 15 to produce the landing gear rod.

31. A method of producing a landing gear beam comprising: performing the method of claim 15 to produce the landing gear beam.

Description

BRIEF SUMMARY OF THE DRAWINGS

[0057] The invention will be better understood upon reading the following description, given in reference to the following appended figures:

[0058] FIG. 1, which schematically shows the blank and the sacrificial mandrel used in a first variant of the method according to the present disclosure to produce a part with symmetry of revolution, hollow over its entire length;

[0059] FIG. 2, which shows said blank in longitudinal sectional view after it has been drilled over its entire length in light of the following production step;

[0060] FIG. 3, which shows the drilled blank in longitudinal sectional view placed in the container before the expansion operation, and the punch preparing to be used to perform the expansion of the blank in the container;

[0061] FIG. 4, which shows, in the same manner, the blank in the process of expansion, before the centering ring is removed that keeps the blank in position in the first stages of the expansion;

[0062] FIG. 5, which shows the blank in the container, at the end of the expansion phase;

[0063] FIG. 6, which shows, in the same manner, the blank in the container, the sacrificial mandrel having been inserted into the space arranged by the punch to that end;

[0064] FIG. 7, which shows, in longitudinal sectional view, the assembly formed by the blank and the sacrificial mandrel upon removal from the container;

[0065] FIG. 8, which shows said assembly in longitudinal sectional view after co-forging thereof;

[0066] FIG. 9, which shows said assembly in longitudinal sectional view during the drilling operation that makes it possible to destroy the sacrificial mandrel and to adjust the inner diameter of the part produced from the blank;

[0067] FIGS. 10 to 16, which schematically show, during the implementation of a second variant of the present disclosure for producing a landing gear rod, the steps that make it possible to obtain a blank-sacrificial mandrel assembly in which the sacrificial mandrel is not present over the entire length of the blank;

[0068] FIG. 17, which shows this same assembly after shaping by upsetting the head of the rod;

[0069] FIG. 18, which shows this same assembly after drawing of the shaft of the rod;

[0070] FIGS. 19 to 21, which show the shaping of said assembly by flattening in a press and edge stamping;

[0071] FIG. 22, which shows the final rod in longitudinal section view, drilled and machined;

[0072] FIGS. 23 to 30, which schematically show, during the implementation of a third variant of the present disclosure for producing a landing gear beam, the steps that make it possible to obtain an assembly formed by a blank and two sacrificial mandrels that leave a portion of the blank in which a sacrificial mandrel is not present;

[0073] FIG. 31, which shows this same assembly after a co-forging that has given it an outer shape close to that of the final beam;

[0074] FIG. 32, which shows said co-forged assembly after the machining, which has given the beam its final condition.

DETAILED DESCRIPTION

[0075] It must be understood that the dimensions of the various parts that will be given in the exemplary embodiments that follow will be the dimensions that are or would be measured when cold, therefore independently of the actual dimensions that the parts in question would have at the various stages of production, if they are in a heated condition during the described step.

[0076] In a first exemplary embodiment, we will describe a method using a single mandrel, in the case at hand a through mandrel, to produce a hollow part.

[0077] First, produced separately, visible in FIG. 1, are:

[0078] a blank 1 made from Ti alloy Ti-10-2-3, with a diameter D of 430 mm and a length of 2366 mm; this is the material from which the part will be made;

[0079] and a blank 2 made from steel E28-3 or E24-2 with a diameter B of 200 mm and a length of 2366 mm, which is intended to make up the sacrificial mandrel.

[0080] Then a hole is drilled with a diameter from about 20 to 25 mm along the axis of the blank 2 made from a Ti alloy, over its entire length, in order to obtain a through opening 3. The aim of this step, which is optional but highly advisable at least for very long parts (with a length on the order of 10 times the diameter of the part or more), is to serve to prime the insertion of the punch 10 that will perform the expansion of the blank 2 while preventing it from deviating from its nominal path during this expansion. One thus obtains a drilled blank 4, visible in FIG. 2.

[0081] Then the blanks 4, 2 are heated, to bring them to temperatures suitable for the treatments they will undergo and which will be seen later. These temperatures are of course able to vary based on local conditions, in particular the transfer times between the furnaces and the expansion installation that will be used, and the times that the blanks 4, 2 spend before undergoing the transformation. These temperatures will be able to be determined by computer simulations and routine tests.

[0082] Then the heated drilled blank 4 is placed in a press. In the illustrated example, the press comprises a cylindrical container 5, placed vertically in the example illustrated in FIG. 3, this container 5 in turn comprising a central housing with diameter A equal to 487 mm, therefore greater than that D of the drilled blank 4 and greater than or equal to the largest diameter Al that the final hollow part will assume, so as to leave a free space 6 between the drilled blank 4 and the inner wall of the container 5 for the future expansion of the drilled blank 4. A centering ring 7 is placed in the lower part of the container 5 to receive the lower end 8 of the drilled blank 4. The centering ring 7 has an outer diameter equal (to within a slight play, allowing it to be placed and removed) to the inner diameter A of the container, and an inner diameter equal (to within a slight play) to the diameter of the drilled blank 4, for example 440 mm in the present embodiment. The upper end 9 of the centering ring 7 is preferably beveled to guide the drilled blank 4 inside the centering ring 7 during its descent into the container 5. FIG. 3 also shows the expansion punch 10, which is, for the moment, nonoperational and is kept above the container 5 while waiting for the following production step. The diameter of this punch 10 is greater than that B of the sacrificial mandrel 2 in order to allow the future insertion of the sacrificial mandrel 2 into the space created by the punch 10. For example, for a nominal diameter of the sacrificial mandrel 2 of 200 mm, it is possible to provide a diameter of 205 mm for the punch 10, with the understanding that the sacrificial mandrel 2 will be used hot and will then have a diameter of about 202 mm, while the punch 10 will be used in an initially cold state, and will only experience a small expansion during its use.

[0083] Although not necessarily mandatory, the use of the container 5 and the centering ring 7 is a preferred embodiment, since it makes it possible to ensure good dimensional control of the shaping of the drilled blank 4.

[0084] The following step, shown schematically in FIG. 4, is a first stage of the expansion of the drilled blank 4 using the punch 10. The latter has a lower end 11 with a conical shape that facilitates the penetration and centering of the punch 10 in the drilled blank 4. The tip of the cone 11 is inserted into the through opening 3, and the punch 10 descends while gradually pushing back the hot metal making up the drilled blank 4 against the inner wall of the container 5 while causing it to fill in the space 6 as the punch 10 advances. This expansion of the drilled blank 4 is therefore done without any material removal. The situation shown in FIG. 4 is therefore achieved, in which the upper part of the drilled blank 4 has an outer diameter substantially equal to A, but without a very strong pressure being exerted on the container 5, while the lower part of the drilled blank 4 has not yet experienced this deformation, since it has not been affected by the progression of the punch 10.

[0085] Then, the centering ring 7 is removed, which is no longer useful, since the upper part of the drilled blank 4 now fills in all of the space 6 up to the level where the punch 10 is formed, and is therefore itself able to ensure the centering of the drilled blank 4 in the container 5. Next, the punch 10 is lowered until it emerges from the lower surface of the container 5 after it has completed the expansion of the drilled blank 4 over its entire length so as to cause it to fill the entire space 6. As shown in FIG. 5, one thus has a drilled blank 4, with an internal space 12 that uniformly has a diameter larger than that B of the sacrificial mandrel 2, as stated above. The punch 10 is then released.

[0086] In the following step, seen in FIG. 6, the sacrificial mandrel 2, with diameter B, is inserted into said internal space 12 of the drilled blank 4. The sacrificial mandrel 2 is not necessarily hot itself, but the drilled blank 4 must still be hot itself. There is a play between them of at least 3 mm to allow this insertion, which the crimping that will follow must be able to bridge.

[0087] Then, for example using the punch 10, a slight compression of the sacrificial mandrel 2 is done, which leads to a crimping of said sacrificial mandrel 2 in the drilled blank 4 such that they constitute an assembly that is inseparable without a deliberate outside action.

[0088] Then the drilled blank 4/sacrificial mandrel 2 assembly, which is as shown in FIG. 7 with a homothetic ratio K that is equal to A/B, is removed from the container 5, and heated to a temperature on the order of 750° C., which allows drilling thereof.

[0089] A co-forging of this assembly is next done in order to obtain, in the non-limiting example shown in FIG. 8, a blank 13 of variable section along its length. The forging leads to a generalized decrease in the outer diameter of the drilled blank 4/sacrificial mandrel 2 assembly and an increase in its length. This decrease is not homogeneous in that, at both ends of the blank 13, a portion is arranged where the outer diameter of the blank 13 is equal to a value Al and where the diameter of the sacrificial mandrel 2 is equal to a value B1. The median part of the blank 13, which, in the illustrated example, represents the largest portion of its length, in turn has an outer diameter A2 conjugated to a diameter of the sacrificial mandrel 2 equal to B2. Between the ends and the median part of the blank 13, there are transition zones 14, 15 where the diameters of the blank 13 and the sacrificial mandrel 2 both decrease progressively.

[0090] According to the present disclosure, during the drilling, a homothetic ratio is preserved on all of the portions of the blank 13 equal to K between the respective diameters of the blank 13 and the sacrificial mandrel 4. One thus has the equalities K=AB=A1/B1=A2/B2, and the transition zones 13, 14 are also affected by this equality.

[0091] Die stamping is next performed of the blank 13/sacrificial mandrel 4 assembly on a die stamping press, in order to give the blank 13 its final outer dimensions.

[0092] Machining of the axial drilling is next done, shown during performance in FIG. 9. The purposes of this are to: [0093] Remove the sacrificial mandrel 2; to that end, it is possible to machine it by turning all of it into chippings, or only machining the periphery of it, for example by hollow core drilling, so as to allow the removal from the blank 13 of the part of the sacrificial mandrel 2 that has remained solid; [0094] And give the internal space 16 of the final part 17 a unique diameter (in the illustrated example) of well-defined value B3, here again by removing material in chippings form.

[0095] It is therefore still may be necessary to perform machining in order to obtain the internal space 16 of the final part 17. However, relative to the machining operations done during conventional methods previously cited, the present disclosure makes it possible to considerably decrease the amount of metal chippings intended to make up the final part 17 to be removed in the form of chippings, which has therefore been prepared superfluously in terms of quantity of material, and also in terms of amount of energy necessary to heat said material (although in the present disclosure, it may also be necessary to reheat the sacrificial mandrel 2, such that the overall energy savings will not be significant if the sacrificial mandrel 2 does not have a significantly lower heat capacity than that of the alloy making up the final part 17). These chippings can still be recovered by being recycled in a melting furnace. They are, granted, mixed with the chippings resulting from the removal by machining of the sacrificial mandrel 4. However, it is easily possible to separate the two types of chippings using a magnetic sorting method, if the sacrificial mandrel 4 is made from steel and if the part to be produced is made from a nonmagnetic alloy. A densimetric or gravimetric separation is also conceivable, when the materials making up the final part 17 and the sacrificial mandrel 4 have a sufficient density contrast to that end, which is the case for, respectively, the Ti alloys and steels, which constitute favored, but non-exclusive examples of materials usable in the application of the present disclosure.

[0096] The process of producing the final part 17 can end, in a known manner, with a heat treatment intended to give it its final metallurgical microstructure, and by machining, in particular of the ends of the final part 17, intended to give them their desired final shape for the anticipated use of the final part 17.

[0097] In a variant of the method according to the present disclosure, it is provided not to use a completely through sacrificial mandrel like in the preceding version shown in FIGS. 1-9, but a blind sacrificial mandrel, to produce a landing gear rod conventionally comprising a shaft and a yoke.

[0098] First, produced separately, visible in FIG. 10, are: [0099] A blank 18 made from Ti alloy Ti-10-2-3, with a diameter D of 430 mm and a length of 2366 mm (or a section of 14.52 dm.sup.2, a volume of 343.59 dm.sup.3, and a mass of 1584 kg); this is the material from which the part will be made; [0100] And a blank 19 made from steel E28-3 or E24-2 with a diameter B of 200 mm and a length of 1150 mm.

[0101] Then a hole is drilled with a diameter from about 20 to 25 mm in the axis of the blank 18 made from a Ti alloy, over a length of 1150 mm, in order to obtain a blind opening 20. The aim of this step, which is optional but highly advisable, in particular for long parts, is to serve to prime the insertion of the punch 10 that will perform the expansion of the blank 18 while preventing it from deviating from its nominal path during this expansion. One thus obtains a partially drilled blank 21 made from Ti alloy, visible in FIG. 11.

[0102] Then the blanks 21, 19 are heated, like in the preceding variant, to bring them to temperatures suitable for the treatments they will undergo and which will be seen later.

[0103] Then the heated partially drilled blank 21 is placed in a press. In the illustrated example, the press comprises a cylindrical container 5, placed vertically in the example illustrated in FIG. 12, this container 5 in turn comprising a central housing 6 with diameter A=490 mm, therefore greater than that D=430 mm of the partially drilled blank 21 and greater than or equal to the largest diameter Al that the final hollow part will assume. A centering ring 7 is arranged in the lower part of the container 6 to receive the non-drilled lower end 22 of the partially drilled blank 21. The centering ring 7 has an outer diameter equal (to within a slight play, allowing it to be placed and removed) to the inner diameter A of the container, and an inner diameter of 440 mm, therefore equal (to within a play of 10 mm) to the diameter of the partially drilled blank 21. The upper end 9 of the centering ring 7 is preferably beveled to guide the partially drilled blank 21 inside the centering ring 7 during its descent into the container 5. FIG. 12 also shows the expansion punch 10, which is, for the moment, nonoperational and is kept above the container 5 while waiting for the following production step. The diameter of this punch 10 is 210 mm, therefore greater than that B=200 mm of the sacrificial mandrel 19 in order to allow the future insertion of the sacrificial mandrel 19 into the space created by the punch 10.

[0104] The following step, shown schematically in FIG. 13, is a first stage of the expansion of the partially drilled blank 21 using the punch 10. The tip of the cone 11 is inserted into the blind opening 20, and the punch 10 descends while gradually pushing back the hot metal making up the partially drilled blank 21 against the inner wall of the container 5 while causing it to fill in the space 6 as the punch 10 advances. This expansion of the partially drilled blank 21 is therefore done without any material removal. The situation shown in FIG. 13 is therefore achieved, in which the upper part of the drilled blank 21 has an outer diameter substantially equal to A (483 mm instead of 490 mm for A), while the lower part of the drilled blank 4 has not yet experienced this deformation, since it has not been affected by the progression of the punch 10. And the diameter of the original blind opening 20 is increased up to about 210 mm, or the diameter of the punch 10. The crimping between the blank 21 and the container 5 must not be too pronounced so as to allow an easy later removal of the blank 21.

[0105] Then, as shown in FIG. 14, the punch 10 is removed and the sacrificial mandrel 19, previously heated to 750° C., is inserted into the blind opening 20 thus widened, the blank 21 in turn being hot. And like in the preceding variant, this insertion is followed by a crimping done using a slight pressure exerted, for example, using the punch 10.

[0106] Then the blank 21 is removed from the container 5, and therefore assumes the form shown in FIG. 15, with its partially drilled portion containing the sacrificial mandrel 19, having an outer diameter, when cold, of 478 mm (therefore slightly smaller than the cold inner diameter of the container, to allow an adequate play between them), the sacrificial mandrel 19 having substantially retained its cold diameter of 200 mm. There is therefore a ratio between these two diameters K=478/200=2.39. The non-drilled part of the mandrel 21 has a diameter of 430 mm when cold, like initially.

[0107] Co-forging of the part 21/sacrificial mandrel 19 assembly is next done at 750° C. in a press, until the assembly is given a cylindrical outer shape, the diameter of which will be compatible with the tooling for upsetting the head of the rod, as will be seen later. In the example shown in FIG. 16, an assembly 23 is obtained with a length of 2610 mm and a uniform outer diameter of 430 mm. The co-forging has reduced the cold diameter of the sacrificial mandrel to 180 mm. There is therefore a ratio of K=430/180=2.39, which has therefore been retained relative to what it was before the co-forging.

[0108] Then, the non-drilled portion 22 of the blank 21 is upset on a suitable tool to give it the shape and dimensions suitable for producing the yoke of the final part, as will be seen later. In the example shown in FIG. 17, this head comprises two frustoconical portions 24, 25 that are connected by a short cylindrical portion 26, and a short cylindrical portion 27 making up the end of the rod. The total length of the assembly 23 is then 2057 mm, knowing that the dimensions of the drilled portion of the blank 21 and the sacrificial mandrel 19 that it contains have not varied.

[0109] Next, at 750° C., drawing of the drilled portion of the blank 21 is done to cause it to go from an outer diameter of 430 mm to an outer diameter of 380 mm. At the same time, the ratio K=2.39 is kept: the diameter of the sacrificial mandrel 19 goes to 159 mm. FIG. 18 shows the result of this drawing.

[0110] Then, as shown in FIG. 19, the drilled part of the blank 21 is flattened on a press at 750° C. in order to give it a total thickness of 280 mm. The length of this drilled part goes to 1915 mm and the total length of the assembly 23 to 2646 mm. The result is visible in FIG. 19.

[0111] Next, die stamping of the assembly is done to give the assembly 23 the desired outer shape for the landing gear rod. To that end, as shown in FIG. 20, the assembly 23 is placed on the lower part 28 of a die. Then, as shown in FIG. 21, the die is closed by pressing on its upper portion 29, and this imparts its final outer shape to the blank 21, with a shaft 30 once again having a circular section, with a homothetic ratio K=2.39 between the inner diameter of the blank 21 made from Ti and the outer diameter of the sacrificial mandrel 19 also being restored, and a yoke 31 that has the exact desired shape. Under the effect of the die stamping, a small amount of the material of the billet 21 is inserted in the gap 32 separating the two portions 28, 29 of the die.

[0112] Machining of the outside of the billet 21 makes it possible to remove the material that was inserted into the gap 32.

[0113] Next, an operation is performed that gives the billet 21 its final shape and dimensions. On the one hand, the inside of the blank 30 is drilled, to remove all of the sacrificial mandrel 19 and part of the metal of the blank 21 in the form of chippings, so as to give the shaft an inner diameter of 230 mm. Drilling is also done in the yoke 31 to give it the desired nominal inner diameter, which, in the illustrated example, is larger than that of the shaft 30. In the illustrated example, the transition between the nominal inner diameter of the yoke 31 and the inner diameter of the shaft 30 is done gradually, the bottom of the drilled cavity in the yoke 31 having a beveled shape.

[0114] The production normally ends with a heat treatment and final machining that gives the blank 21 its precise final dimensions and therefore transforms it into a landing gear rod.

[0115] In another variant of the present disclosure, for example intended to produce landing gear beams, it is possible to use two sacrificial mandrels, in the manner that will be explained.

[0116] First, produced separately, visible in FIG. 23, are: [0117] A blank 33 made from Ti alloy Ti-10-2-3, with a diameter D of 430 mm and a length of 1677 mm (section: 14.52 dm.sup.2, volume: 243.53 dm.sup.3, mass 1124 kg); this is the material from which the beam will be made; [0118] And two blanks 34, 35 made from steel E28-3 or E24-2 with a diameter B of 200 mm and lengths of 640 and 750 mm, respectively intended to make up a first 34 and a second 35 sacrificial mandrel.

[0119] It must be understood that the fact that the two sacrificial mandrels 34, 35 have different lengths is only required by the desired geometry for the described exemplary beam to be produced. This variant of the method could very well use two sacrificial mandrels with the same length, if this was compatible with the geometry of the part to be produced.

[0120] It is not mandatory for the two sacrificial mandrels 34, 35 to be made from the same material, if there was an advantage in these materials having different yield stresses, for example because the targeted geometry for the final part required significantly different deformations for the portions shaped using each of the sacrificial mandrels 34, 35, and these different deformations were better ensured with sacrificial mandrels 34, 35 having different properties.

[0121] Then two blind holes 36, 37 with a diameter of about 20 to 25 mm are drilled along the axis of the blank 33 made from a Ti alloy, over a length of 630 mm for the first 36 and 747 mm for the second 37, in order to obtain two blind openings. The aim of this step, which is optional but highly advisable, in particular for the long parts, is also to prime the insertion of the punches that will perform the expansion of the blank. One thus obtains a partially drilled blank at each of its two ends 38, visible in FIG. 24.

[0122] Then, in the illustrated preferred example, the partially drilled blank 38 is placed in a container 5 equipped with a centering ring 7, identical in terms of composition and dimensions to that used in the preceding examples. In the case illustrated in FIGS. 25 to 27, the side of the partially drilled blank 38 comprising the longest blind hole 37 is placed toward the upper portion of the container 5, such that this longest blind hole 37 is the first to be widened and elongated by the punch 10 during the step shown in FIG. 26, qualitatively corresponding to that shown in FIG. 13 for the preceding example. The punch 10 pushes the alloy of the blank 38 back against the inner wall of the container 5, without excessive crimping. It arranges an elongated and widened blind opening 37, the length of which makes it able to close the second sacrificial mandrel 35, that is to say, the longest sacrificial mandrel, prepared beforehand, as shown in FIG. 27. The second sacrificial mandrel 35 is next crimped, as previously explained regarding the other examples.

[0123] Then the blank 38 containing the second sacrificial mandrel 35 is removed from the container 5, the centering ring 7 is removed from the container 5, and the partially drilled blank 38 is reinserted into the container 5 with, this time, the side of the blank 38 comprising the shortest blind hole 36 toward the upper portion of the container 5. The centering of the blank 38 in the container 5 is now ensured by the portion of the blank 38 that was expanded during the preceding step. One is therefore in the situation of FIG. 28, with the punch 10 ready to widen the blind hole 36 and to expand the blank 38 in its portion comprising the shortest blind hole 36. Once the expansion is done, the first sacrificial mandrel 34, which is the shortest of the two sacrificial mandrels 34, 35, is inserted into the expanded hole 36, and one is in the situation of FIG. 29.

[0124] In other words, the blank 33 is not expanded over its entire length and said second sacrificial mandrel 35, the longest in the illustrated case, therefore does not extend over the entire length of said blank 33 during its insertion and the corresponding expansion of the blank 33. One next turns the blank 33 over and presses the punch 10 on the other end of the blank 33, performs the expansion of another portion of the blank 33 while creating another internal space within the blank 33, and inserts the first sacrificial mandrel 34, the shortest in the illustrated case, into said other internal space of the blank 33.

[0125] The assembly formed by the expanded blank 38 and the two sacrificial mandrels 34, 35 is removed from the container and, as better shown in FIG. 30, assumes the form of a blank 38 comprising two cylindrical portions each containing a sacrificial mandrel 34, 35 and connected by a non-perforated portion, comprising a cylindrical central portion 39 whose diameter is equal to the original diameter of the blank 38 and two frustoconical portions 40, 41 that connect it to the cylindrical portions containing the sacrificial mandrels 34, 35. The outer diameter of the blank 38 is 478 mm and the diameter of the sacrificial mandrels 34, 35 is 200 mm. The ratio K is therefore equal to 478/200=2.39.

[0126] The blank 38 and the sacrificial mandrels 34, 35 that it contains are then forged at 750° C., in order to obtain the part 42 shown in FIG. 31. At each end of said part 42 are successively found: [0127] A cylindrical portion 43 with outer diameter A1=393 mm, containing one of the sacrificial mandrels 34, 35 whose diameter has been reduced by the forging to 164 mm, which has retained the ratio K=2.39; [0128] A frustoconical portion 44 where both the outer diameter of the part 42 and the diameter of the mandrels 34, 35 decreases gradually, while retaining the ratio K=2.39; [0129] A cylindrical portion 45 with outer diameter A2=347 mm and where the diameter B2 of the sacrificial mandrel 34, 35 that it contains is 145 mm, the ratio K=2.39 having been retained; [0130] A solid portion 46 not containing a sacrificial mandrel portion and comprising two frustoconical portions 47, 48 connected by a cylindrical portion 49 with a diameter of 403 mm, and the function of which will be seen later.

[0131] In a variant, this part 42 can be obtained by a method comprising performing flattening, then edge stamping and machining, like in the preceding variant.

[0132] Lastly, the production of the beam 42 ends with machining that makes it possible to give the beam its final outer dimensions, remove the sacrificial mandrels 34, 35 in the form of chippings and develop an inner diameter of the beam 42 of 230 mm in the portions where the sacrificial mandrels 34, 35 were present, and an inner diameter of 155 mm in the portion where they were absent corresponding to the solid portion 46. Furthermore, this portion 46 undergoes drilling in its cylindrical portion 49, along an axis perpendicular to the longitudinal axis of the beam 42, to allow the beam to be connected to the shock absorber of the landing gear.

[0133] Of course, the examples that have been described and illustrated are not limiting, both in terms of the general shapes of the final parts that have been described and their dimensions.

[0134] The use of the container 5, in which the drilled blank 4, 21, 38 will be inserted, is merely one favored exemplary embodiment. It is possible to consider performing the various operations for drilling and insertion of the sacrificial mandrel(s) 2, 19, 34, 35 without the assistance of this container 5 and the associated centering ring 7.

[0135] Likewise, the heating of the drilled blank 4, 21, 38 before it is inserted into the container 5 (or more generally its drilling by the punch 10) is absolutely not mandatory.

[0136] Models and/or routine tests will be able to show one skilled in the art whether these operations are essential in order to obtain a satisfactory result.

[0137] Another variant of the present disclosure can consist of using, as punch 10, the sacrificial mandrel 2, 19, 34, 35 itself, by choosing to that end, in order to form the sacrificial mandrel 2, 19, 34, 35, a material with the appropriate mechanical properties in that they are compatible with both functions.

[0138] Likewise, the present disclosure is not limited to the case where one starts with blanks and sacrificial mandrels having a circular section, constant or variable along the length of the part, or to the case where the final part is entirely a part with a symmetry of revolution. One skilled in the art will easily be able to adapt the present disclosure to the case where certain portions of the final product do not have a circular section, for example after die stamping or machining. A container 5 and/or a punch 10 with non-cylindrical section(s) could contribute to bringing the blank or its internal space closer to the desired final shape by minimizing the subsequent deformation and machining that may be necessary.

[0139] It also goes without saying that the blanks and the sacrificial mandrels, as well as the final part that has been produced using the described method, can also undergo other operations in addition to those that have been described, for example heat treatments or shaping with or without removal of material, that would be compatible with the different steps of the inventive method. The important point is for the method for producing the final part to comprise at least the steps that have been described as being essential to implement the method according to the present disclosure.