FR2677281A1 - Method of manufacturing an article by superplastic forming and diffusion welding, and device for the implementation of this method - Google Patents

Abstract

A stack (48) of titanium plates (50, 52, 51) is placed on an attachment table (28) in a vacuum chamber (10). One of the touching surfaces of each touching-surface pair has an application of a masking material, according to a desired design (pattern), in order to prevent diffusion welding. A pump (16) evacuates the vacuum chamber (10) and heating devices (22) heat the stack (48) in order to evaporate the volatile binder of the mask. When all the binder has been removed, the attachment table (28) is moved with respect to an electron beam from a gun (20) in order to weld the edges of the plates (50, 52, 51) together so as to form a sealed assembly. The volatile binder is removed rapidly and oxidation of the titanium is prevented during the elimination of the binder by baking (firing). The sealed assembly is then heated and subjected to external pressure in order to weld the plates together by diffusion. The structure, rendered integral, is then heated and subjected to an internal pressure in order to form, in a superplastic manner, one of the plates so as to produce an article of a predetermined shape.

Description

 The present invention relates to a ptucédé for manufacturing an article by superplastic forming and diffusion welding.

 It is known to manufacture metal articles by superplastic sealing and diffusion probing of metal parts. These metal parts may consist of a single metal element, metal alloys and metal matrix composites. At least one of the metal parts must be deformable in elongation superplastically.

 The surfaces of the two pieces to be joined are cleaned. and at least one surface of one or more plasicurs of the parts is coated in preselected areas with a material which avoids diffusion bonding. The pieces are arranged in a stack, and the edges of the pieces are probed together, except where a first pipe is welded to the pieces to form an assembly. The assembly is placed in an autoclave, and heated to remove by baking the binder of the material used to avoid diffusion welding. The assembly is then emptied through the pipe, and the pipe is sealed.The sealed assembly is placed in a pressure vessel, and it is heated and pressurized to weld together the pieces, so as to form a solidarized structure. Diffusion welding occurs when two contiguous surfaces are pressed together under temperature, time and pressure conditions which allow mutual atomic exchange across the interface. The first pipe is removed and a second pipe is attached to the welded assembly. in place of the first hose assembly. The solidarized structure is disposed between suitably formed dies and is placed in an auteclave. The integral structure and the dies are heated, and a pressurized fluid is fed to the interior of the secured structure, via the second pipe, so as to cause the superplastic forming of at least one of the parts, to produce an article contespondant the shape of the dies.

 In the known method, the welding of the pipe on the parts. then to remove the vaporized binder and to empty the assembly, is consuming time. The use of the hose to remove the vaporized binder from the assembly is also time consuming. In addition, the assembly may contain air when heated to vapotize the binder and this may result in oxidation of the surfaces of the parts which must then be diffusion bonded.

 It is an object of the present invention to provide a novel method of manufacturing an article by superplastic forming and diffusion probing, which does not have the aforementioned disadvantages.

Thus, the present invention provides a method of manufacturing an article by superplastic forming and diffusion shaping of two metal parts, comprising the steps of
a) apply a mask material to avoid diffusion bonding in
preselected areas of at least one of the surfaces of at least one of the
minus two metal parts,
b) assemble the at least two pieces of bunion to form a stack (the pieces
one on the other, so that their surfaces are in contact with each other,
c) placing the stack in a vacuum chamber,
d) empty the vacuum chamber,
e) heat the stack while it is inside <the vacuum chamber, polish
evaporate a volatile binder from the canvas masflller material by vacuuming tlp
continuous way in the vacuum chamber, so as to eliminate the volatile binder
between the two rooms and the vacuum chamber,
f) weld the edges of the two-piece halves while stacking is at
the inside of the vacuum chamber, to make a sealed assembly,
g) apply heat and pressure in the thickness of at least two
parts, to weld together by diffusion the aii least denxs parts. in
zoues other than the preselected zones, so as to form a structure
secured,
h) heat the solidarized structure, and pressurize the structure internally
secured, so that the preselected areas of at least one of the parts
are superplastically formed to produce a form article
predetermined.

 The stack is preferably heated to a temperature between 250 ° C and 350 ° C to evaporate the volatile binder from the mask material.

 The edges of the at least two pieces are preferably welded using an electron beam.

 When the pieces are made of titanium alloy. the parts are heated to a temperature of 850 C or higher, and the applied pressure is greater than or equal to 20,26 bar (294 psi) to subsequently weld the parts by diffusion and the structure to form a bonded structure.

 Preferably, the pieces are formed at a temperature between 900 ° C and 950 ° C, and the applied pressure is between 20.26 bar (294 psi) and 30.39 bar (441 psi).

 The solidarized structure is heated to a temperature equal to 850 ° C, to form it superplastically.

 Preferably, the solidarized structure is heated to a temperature between 900 and 950 C.

 The present invention also provides a vacuum chamber for use in the treatment of at least two metal parts, for their extrusion probing and superplastic forming comprising pump means arranged to empty the vacuum chamber, hubs energy beam welding means means for causing a relative movement between the welding radius of the energy beam welding means and a stack of parts placed in the vacuum chamber, to allow the edges of the at least two metal parts to be welded together, preferably.

the vacuum chamber has a pressure vessel designed to withstand internal pressures ranging from vacuum to 20.26 bar (1294 psi).

 Preferably, the pressure vessel is designed to withstand internal pressures of up to 30.39 bar (441 psi).

 Preferably, the means for driving relative movement between the welding radius and the stack of parts comprises a movable attachment table in two perpendicular directions. and the stack of pieces can be arranged on the attachment table.

 Preferably, the energy beam welding means comprises an electron beam gun.

 Preferably, the vacuum chamber comprises a first part in which are located the fixing table and the heating means, and a second part in which the electromagnetic beam gun is located.

Preferably, valve means. positioned between the pretilière and the second part, selectively isolate the electron beam gun dil the first part of the vacuum chamber,
The energy beam welding means may include a laser beam gun.

 Preferably, the heating Libyans comprise a plurality of radiant heating devices.

 Preferably, many reflectors are provided to reflect the radiant heat on the parts.

 The heating means may comprise several inductive heating devices.

 The inductive heating devices can be mounted on the fixing table.

The present invention will be described in more detail, by way of non-limiting example, with reference to the accompanying drawings, in which - Figure I is a sectional view of a vacuum chamber for use
in the treatment of inetallic parts. for their superplastic and
their diffusion bonding according to the present invention.

FIG. 2 is a sectional view along line AA of FIG.
FIG. 3 is a sectional view of a variant of a vacuum chamber intended for
to be used in the treatment of metal parts for their forming
superplastic and their diffusion bonding. and for diffusion welding
of metal parts according to the present invention,
FIG. 4 represents an exploded view of a stack of parts which are formed
superplastically and diffusion bonded to form an attiele according to
the present invention
- Figure 5 is a sectional view of another vacuum chamber rine. intended to be
used in the treatment of metal parts for their forming
superplastic and their diffusion bonding, according to the present invention.

 In FIG. 4, three titanium alloy plates 50, 51, 54 are assembled to form a stack 48.

 Before assembling the plates 50, 52, 54 to form a stack 48. the contiguous surfaces 56, 58, 60 and 62 of the plates 50, 52, 51 are prepatrated for the diffusion bonding, by chemical cleaning. A mask material is applied to one of the contiguous surfaces 56 and 58, in this example the contiguous surface 58. A mask material is also applied to one of the adjoining surfaces 60 and 62 in "and, for example, the adjoining surface 62. The mask The mask may comprise, for example, the mask known under the name of "Stopyt 62A", and may include powdered yttria in a binder and a solvent.

which is sold by a US company called GIE Setvice Cotporation.

The mask material is applied in the desired patterns 64 and 66, shown as 1: 1 dark areas in FIG. 4, by the stencil printing method. The desired patterns 64 and mask material avoid diffusion welding between preselected areas of the plates 50, 52 and 54. In this example, the mask is applied in straight lines. it can be applied according to dots or other suitable drawings, including the article partieulier to manufacture, the three plates of titanium alloy 50, 52 and 54, are then assembled to fot mer etnpil.ige 48 The plate 50 has a pair of pin holes 68 68 which are aligned axially.
with corresponding pinholes 70 in the plate 52 and with corresponding pinholes 72 in the plate 54 to ensure the correct relative positioning of the three plates 5 (), 52 and 54 in the stack 48. The plates 5 .? and 54 are maintained in this relative positioning by a pair of pegs (not shown), which are inserted into the aligned dowel holes 68, 7 () and 72.

 The stack 48 is then placed in a vacuum chamber. which will be described in more detail below. The vacuum chamber is emptied, and then the stirring 48 is heated to a temperature between 250 C and 350 C, to remove by cooking or to evaporate the binder of the mask material During baking removal of the binder. the vacuum chamber is continuously emptied to remove the binder from between the plates and the vacuum chamber.

 After the binder has been removed, which is determined either by the control of the binder levels in the extracted gas tle the vacuum chamber: either by maintaining the vacuum chamber at the temperature between 250 C and 350 C during a drip predetermined. The titanium plate boids are welded together, in this example by an electron beam, to make a sealed assembly. The pressure in the vacuum chamber is then allowed to return to atmospheric pressure.

 Heating the stack of non-welded plates in the vacuum chamber, which is continuously emptied, allows the volatile binder to be removed from the stack by the entire periphery of the stack. along all the edges of the plates. This allows the volatile binder to be removed much more rapidly than in the previously known process. This also avoids fixing a pipe on the stack, and thus there is a saving of time. Lin additionally, by heating the unfused stack of plates in the vacuum chamber continuously emptied.

there is no air present in the vacuum chamber to oxidize the surfaces of the plates.

 The sealed assembly is removed from the vacuum chamber. and it is transferred in titi autoclave. The sealed assembly is preferably removed from the town chamber by robotic arm ion, and is automatically transferred to and placed in the autoclave without manual intervention. Manual handling of the sealed assembly between the vacuum chamber and the autoclave is undesirable. Because the mask is brittle and can easily be damaged.

 The temperature in the autoclave is increased so that the sealed assembly is heated to a temperature greater than or equal to 850 C and the argon pressure in the autoclave is increased to a pressure greater than 2 () atmspheres or 2 (), 26 bar (294 psi), and maintained at that temperature and pressure for a predetermined time. Preferably, the assembly is heated to a temperature between 900 ° C. and 950 ° C. and the pressure is between 20, 26 hrs (294 psi) and 30.39 bar (441 psi). sealed is heated to 925 C, and if the pressure is increased to 20, 67 bar (3 () 0 psi). the temperature and pressure are constant for about two hours. The pressure is then reduced to ambient pressure, the diffusion bonding having been completed and the sealed assembly, then a solidarized structure, is removed.

 A pipe is fixed on the solidarized structure, and argon is introduced into the zones that contain the mask, inside the solidarized structure, to remove the adhesion caused by the pressure of the sounding diffusion. Argon is carefully introduced into the areas that contain the mask. and the argon infiltrates through the mask and finally reaches the opposite end of the solidarized structure. argon may initially be injected between two pieces, and when the opposite end is reached, argon may be injected at the inlet end between two other pieces. the length of the interior of the solidarized structure, so as to destroy the adhesion between the mask and the plates, caused during the diffusion probing step.

 This step is performed at room temperature, because the metal is elastic at room temperature, and the minimal elongation deformation that takes place does not exceed the yield strength. Therefore, the solidarized structure returns to its shape when the pressure is removed at the end of the stage.If we try to achieve this stage while the structure is at the common temperature of the diffusion bonding and superplastic forming, there is a serious risk of progressive plastic loss in the direction of the length of the integral structure, rather than a sinaltaneous deformation on the whole structure. In such circumstances, the rupture of the solidified stuiettire occurs frequently.

 The solidarized structure is placed between two suitably shaped segment mats positioned within the autoclave in which the town is made so as to avoid contamination of the integral titanium structure.

 The solidarized structure is heated again maltees at a temperature greater than or equal to 850 C, preferably between 900 C and 950 C. In this example, the matrices and the solidarized structure are heated to 925 C. Argon is introduced into the structure secured between the adjacent plates, so as to force the plates to move away from each other in the areas comprising the mask, and to force the parts spaced from the outer plates to conform to the shape of the respective matrices, which produces an internal structure that depends on the drawings of the applied mask.

The amplitude of movement of at least one of the plates during deformation. is such that it requires superplastic deformation in elongation. The term "superplastic" is a standard term in metal forming technology and will not be described here,
In order to obtain a superplastic forming of the metal without breaking the metal which becomes thinner, the argeon is introduced by pulse sets according to a precalculated rhythm which corresponds to a desired rate of stress as taught in books published for a long time. The method ensures that the metal is subjected to stress stress which provides the maximum elongation strain rate. at any time in the procedure. The rate of application in / or the volume of the gas pulses can thus vary during the expansion of the plates.

 At the end of the superplastic forming, the inert atmosphere of argen and the gas pressure inside the solidarized structure are maintained until the structure is cooled to room temperature. The solidified structure is then removed from the autoclave and the pipe is removed. This solidarized structure can be finished, but it may be necessary to perform a final machining of the solidarized structure to produce the finished article.

 according to a variant of the method, the stack 48 is prepared in the same manner as described above. the stack 48 is then placed in a vacuum chamber and autoclave apparatus, which will be described in more detail below. The combined vacuum chamber and autoclave apparatus is evacuated, and Binder is heated to a temperature between 250 C and 350 C to evaporate the mask binder.

During baking removal of the binder, the combined vacuum chamber and autoclave apparatus is emptied continuously to remove the binder from between the plates and the combined vacuum chamber and autoclave apparatus. After the binder has been removed, the edges of the titanium plates are welded together, in this example by an electronic niyon, to provide a sealed assembly.

 The temperature in the combined vacuum chamber and autoclave device is increased so that the sealed assembly is heated to a temperature above 850 C and the argon pressure in the autoclave is increased to a pressure 20.26 bar (294 psi), and the temperature and pressure are maintained for a predetermined time. Preferably, the sealed assembly is sealed at a temperature between 900 ° C and 95 ° C and the pressure is between 2 (), 26bar (294 psi) and 30.39 bar (441 psi). The pressure is then reduced to ambient pressure. . the diffusion welding having been completed, and the sealed assembly, which is then a solidarized structure, is removed.

 The use of a combined vacuum chamber and autoclave device eliminates the need to move the sealed assembly from the vacuum chamber to an autoclave for subsequent superplastic forming. This has the advantage that it does not have the movement of the sealed assembly, and therefore no possibility of damaging the mask while it is brittle between the stages of binder removal by welding and welding. by diffusion.

 After the diffusion bonding, the bonded structure is treated in the same manner as previously described.

 A vacuum chamber 10 for use in the treatment of metal parts for superplastic forming and diffusion probing in the first method described above. FIG. 1 and 2. Ia vacuum chamber 10 has a main portion 12 and a second portion 14. A pump 16 is connected to the interior of the chamber 7 vidce 10. through a pipe 18, to empty the vacuum chamber 10.

 An electron beam gun 20 is located in the second portion 14 of the vacuum chamber 10, and is arranged to direct its electron beam into the main portion 12 of the vacuum chamber 10.

 An attachment table 28 is disposed in the main part 12 of the vacuum chamber 10, and the fixing table 28 is movable in two directions perpendicular to the inside of the main part 12 of the vacuum chamber 10, by the The stack 48 of the sheets 5 (), 52 and 54 is dispr (es) on the attachment table 28, and is movable through the mechanism 30 so that the edges of the plates 50, 52 and 54 meet the path of the electron beam, to weld the edges together to form the sealed assembly.

 Cliaufflige devices 22 are provided inside the main part 12 of the vacuum chamber 10, to heat the stack 48 of the plates 50, 52 and 54, before the edges of the plates 50, 52 and 54 are welded together. to evaporate the binder dii mask applied to the surfaces of the plates. Heating devices 22, in this example, are arranged above the fixing table 28 and the mechanism 30, and the heating devices 22 comprise several radiant heating elements 24.

Several reflectors 26 are also provided above the tadiant heating elements 24.

to redirect on stacking 28 the nîdiante heat emitted vet s the top.

The attachment table 28 is movable in a first direction relative to the first base member 38. and the attachment table 28 and the first base member 38 are movable in a second direction relative to a second base member 46. The fixing table 28 comprises a first pair of members 32A. which have threaded coaxial openings, through which extends a first rod 34A dated from an external thread. The ends of the first rod 34A are rotatably mounted in a first pair of coaxial openings in end members 36A on the first base member 38. The attachment table also includes a second pair of members 32A, which have threaded coaxial openings through which extends a second rod 34B with an external thread. The ends of the second rod 34B
are rotatably mounted in a second pair of coaxial openings in these members
36B on the first base member 38. The first base member 38 comprises a third pair of members 40A, which have coaxial threaded openings at
through which a third rod 42A with an external thread is passed. The ends of the third rod 42A are rotatably mounted in a first pair of coaxial openings in end members 41A on the second member member.
base 46. IR first base member 38 has another pair of members 40B which have threaded coaxial openings, through which passes a fourth rod 4213 provided with an external thread. The ends of the fourth rod 42B are rotatably mounted in a second pair of coaxial openings in end members 44B on the second base member 46.

Suitable motors are shown) or other suitable means provided for
rotate the rods 34A, 34B. 42A and 4213, to move the attachment table 28 so that it moves the edges of the stack 48 of the plates in the electronic beam, to weld together the edges of the stack. I, a vacuum chamber 10 of Figures 1 and 2 is designed to be used in a pressure range from vacuum to atmospheric pressure.

 A combination apparatus of vacuum chamber and autoclave 1 10. for use in the treatment of metal plates for their superplastic forming and diffusion bonding according to the second method described above, is shown in FIG. combined vacuum chamber and vacuum apparatus 11 comprises a pressure vessel designed to be used in a pressure range from vacuum to at least 20.26 bar (294 psi), and preferably withstands internal pressures. up to 30.39 bar (441 psi).

The combined vacuum chamber and autoclave assembly 110 includes a main portion 12 and a second portion 14. A pump 16 is connected to the interior of the combined vacuum chamber and autoclave 110, via 'a pipe
18, to empty the combined vacuum chamber and autoclave apparatus, and to supply argon gas to pressurize the combined vacuum chamber and autoclave apparatus.

The combined vacuum chamber and autoclave apparatus 11 is similar to that of FIGS. 1 and 2, and includes an electron beam gun 20. disposed in the second portion 14, and adapted to direct its electronic beam in the main portion 12. An attachment table 28, disposed in the main portion 12, is movable in two directions perpendicular to the interior of the main portion 12, by The mechanism 30 is identical to that of FIGS. 2. The stack 48 of plates is arranged on the fixing table 28, and it is made easy by means of the table 28.
of the mechanism 30, to move the edges of the plates 50, 52 and 54 in the path of the
electron beam, in order to weld together the edges to form the dry assembly.

Heating devices 22, identical to those of FIGS. 1 and 2, are also provided for evaporating the binder of the mask applied to the surface of the plates.
The combined vacuum chamber and autoclave apparatus 10 also includes a valve 80 for isolating the second portion 14, and capable of isolating the electron beam gun 20 from the main portion 12 of the combined vacuum chamber apparatus. autoclave 110, while the main portion 12 is heated and pressurized to weld together the stack plates together. This prevents the electron beam gun from being damaged by high temperatures and / or high temperatures.
pressures present during the diffusion bonding step. The valve 80 can also be used to isolate the second portion 14, and the electromic ray gun 211, the pallia
main 12 during the elinmination by baking binder of the stack 48.

 The vacuum chamber 10 of FIGS. 1 and 2 can also be provided with an alve to isolate the second portion 14, and the electron beam gun 20 from the main portion 12 during the baking removal of the binder of the same. stacking 48.

 FIG. 5 shows another polishing chamber 210 for waxing used for treating metal plates for their supermoplastic forming and diffusion bonding, according to the first method described above. The empty chamber 210 comprises a pump 16 connected inside the vacuum chamber 210 by a pipe 18, in order to empty the vacuum chamber 210.

The vacuum chamber 210 is similar to that of Figures I and 7, but it does not have a second part or electron gun. Instead, the vacuum chamber 210 has a window 90 through which a ray laster from a laser beam gun 92 can be directed to the interior of the doorway.
The fixing table 28 is movable with respect to the path of the laser beam, to weld together the edges of the plates, to polish the sealed assembly.

 Alternatively, an optical system may be used to deflect the laser beam, to weld together the edges of the plates or to use a combination of a radius deflection and a movement of the attachment plate.

 Other suitable heating devices can be used, for example inductive heating coils can be arranged in the upper surface of the fixing table 28. to limit heating to the stack 48 of plates placed on the fixing table .

 Other welding techniques, which can be used in vacuum, can be used to weld the edges of the pieces.

 Although the foregoing description refers to titanium plates or titanium pieces, the present invention is equally applicable to parts made of other elemental metals, metal alloys and metal matrix composites, which may be diffusion welded, provided that one of the parts is capable of superplastic deformation in elongation. Aluminhun and stainless steel are capable of superplastic deformation at elongation at suitable temperatures and pressures.

 The process is suitable for the manufacture of heat exchangers. turbo-machine components, for example, fan blades, blower duct outlet guide islands, etc.

 Although the foregoing description refers to a stack of sorted metal plates, it is possible to use stacks comprising two metal plates or stacks comprising four or more metal plates, depending on the particular article to be manufactured.

Claims (20)

claims  1. A method of manufacturing an article by superplastic forming and diffusion bonding of at least two metal parts comprising the steps of:  a) apply a shield material to avoid diffusion bonding in  preselected areas of at least one of the surfaces of at least one  minus two metal parts,  b) assembling the at least two parts to form a stack of parts  one on the other, so that their surfaces are in contact with each other.  c) placing the stack in a vacuum chamber,  (d) evacuate the vacuum chamber,  e) heat the stack while it is inside the vacuum chamber, for  evaporate a volatile binder of mask material, while evacuating  continuous way in the vacuum chamber, so as to eliminate the volatile binder  between the two rooms and the vacuum chamber,  f) weld the edges of the at least two pieces while the stack is at  inside the vacuum chamber, polish achieve a sealed set,  g) apply heat and pressure in the thicknesses of at least two  parts, to weld together by diffusion the at least two parts, in  areas other than the preselected areas, so as to form a structure  secured,  h) heat the solidarized structure, and pressurize the structure internally  solidarized, so that the preselected areas of shinbone one of  parts are formed superplastically. in order to produce an article of  predetermined form.  2. A method of manufacturing an article according to revendieation @ l, comprising, after  the step of welding the edges of the minus two pieces to achieve a sealed assembly, and  before the step of applying heat and pressure in the thickness of at least  two pieces to weld together by diffusion the mollis two pieces, the steps  to remove sealed whole from the vacuum chamber, and place the whole sealed in titi  autoclave.  3. A process according to claim 1 or claim 2, wherein the stacking  is heated to a temperature between 250 and 350 C, to evaporate the binder  volatile mask material.  4. A process according to any one of claims 1 to 3, wherein the edges  at least two pieces are welded using an electronic beam.  5. A process according to any one of claims 1 to 4, wherein, when the parts are made of titanium alloy, they are heated to a temperature greater than or equal to 850 C, and the applied pressure is greater than or equal to 20.26 bar (294 psi) for soldering the parts together in a solid structure,  The method of claim 5 wherein the parts are heated to a temperature of 900 to 950 ° C, and the applied pressure is 20.26 bar (294 psi) to 30.39 bar (441 psi). .  7. A process according to claim 5 or claim 6 wherein the solidarized structure is heated to a temperature greater than or equal to 850 C, to superplastically form the bonded structure.  8. A process according to claim 7, wherein the solidarized structure is heated to a temperature between 900 C and 950 C.  9. The method of claim 1, including monitoring the binder levels evacuated from the vacuum chamber while the vacuum chamber is continuously evacuated, to determine when substantially all of the binder has been removed from between them. two pieces.  10. Vacuum chamber for use in the treatment of at least two metal parts, for their diffusion welding and superplastic forming, comprising pump means arranged to empty the vacuum chamber, welding means by energy beam, means provided to cause a relative movement between the welding radius of the energy beam sounding means and a stack of parts placed in the vacuum chamber, for penflettre alla edges of the at least two metal parts d to be welded together. characterized in that heating means (22) are provided for heating the stack (48) of at least two metal pieces (50, 52, 54) placed in the vacuum chamber (I f)). for evaporating a volatile binder of a mask material applied to preselected areas of at least one of the joined surfaces of the metal pieces (50, 52, 54-).  1. A vacuum chamber according to claim 10, wherein the vacuum chamber (110) serves both as a vacuum chamber and as an autoclave. the vacuum chamber (1 10) has a pressure vessel designed to withstand pressures ranging from vacuum to at least 20.26 bar (294 psi).  Vacuum chamber according to claim 11, wherein the pressure vessel (12) is designed to withstand internal pressures up to 30.39 bar (111 psi).  A chamber according to claim 10, wherein the means (28, 30) for causing a relative movement between the welding beam and the pile (48) of parts (50, 52, 54) having a fastening table (28). ) movable from both perpendicular directions, and the stack (48) of pieces (50, 52,54) can This positioned on the attachment table (28).  14. Vacuum chamber according to claim 10, wherein the welding means (20) by energy beam comprise an electron beam gun.  15. Vacuum chamber according to claim 1d, wherein the vacuum chamber (1 10) comprises a prelllicre. portion (12), in which are fixed the fixing table (28) and the heating means (22), and a second portion (14) in which is located the barrel (20) electronic beam.  16. Vacuum chamber according to claim 15, wherein the valve means (80), positioned between the first and second parts (19, 14) of the vacuum chamber, selectively isolates the radius barrel (20). of the first part (12) of the vacuum chamber (I 10).  17. Vacuum chamber according to claim 10. wherein the welding means (92) by energy beam comprelluellt a laser beam gun.  18. Vacuum chamber according to claim 10, slabs which the heating means (22) comprise a plurality of radiant heaters (24).  19. Vacuum chamber according to claim 18. wherein a plurality of reflectors (26) are provided for reflecting the radiant heat on the parts (50, 52, 54).  20. Vacuum chamber according to claim 1 (), wherein the heating means (22) comprise several inductive heating devices,  21. A vacuum chamber according to claim 10, wherein the inductive heating apparatus is clumped onto the fixture table (281).  22. A vacuum chamber according to claim 10, wherein control means are provided for controlling the level of binder discharged from the vacuum chamber.