Method for assembling metal parts of different sizes and centrifugal diffuser produced by method
By forming grooves on the turbine centrifugal diffuser cover to guide the high-energy weld beam, the problems of deformation and weld beam deflection during blade assembly were solved, achieving stable and precise assembly results, applicable to metal parts of different qualities.
Patent Information
- Application Number
- CN202380043362.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-30
- Filing Date
- 2023-05-30
- Publication Date
- 2025-01-10
AI Technical Summary
Existing technologies for assembling turbine centrifugal diffuser blades and covers suffer from deformation and uneven solder due to brazing, especially during electron beam welding, where quality differences lead to weld beam deflection and assembly instability.
By forming grooves on the surface of the metal cover, a high-energy fusion welding beam is guided to assemble the blades with the cover. The shape of the grooves is similar to the blade profile, ensuring the stability and accuracy of the fusion welding beam, and is suitable for assembling parts of different qualities.
Stable assembly of components of different quality was achieved, avoiding brazing deformation and weld beam deflection, improving assembly accuracy and efficiency, and reducing complexity and cost.
Smart Images
Figure CN119301371A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for assembling a first metal part and a second metal part of different mass (or volume), wherein the second part is welded to the first part through a groove formed in the first part. The invention also relates to an assembly of a metal cover and at least one metal blade obtained by this method, and also to a centrifugal diffuser for a turbomachine comprising such an assembly.
[0002] The invention has application in the aeronautical field, in particular in the field of assembling metal parts for aircraft turbines. Background Art
[0003] Aircraft turbomachines, in particular turbomachines of the gas turbine type, comprise different stages mounted around a central rotating axis. Figure 1 An example of a turbomachine is schematically shown. In this example, the turbomachine 10 includes a rotating shaft 11 extending along a central axis AA, around which a fan 12, a compressor 13, a combustion chamber 14 and a turbine 15 are mounted in a direction from upstream to downstream. When the turbomachine 10 is in operation, an airflow enters the turbomachine through the fan 12; the airflow is then compressed by the compressor 13, then mixed with fuel and combusted in the combustion chamber 14, then expanded in the low-pressure turbine 15, and then discharged through the nozzle 16.
[0004] At the outlet of the compressor 13, a centrifugal diffuser 20 delivers the gas flow towards the compression chamber 14. The centrifugal diffuser 20 (more simply referred to as a diffuser) comprises a partially planar circular cover to which the blades are attached. Typically, the blades are attached to the cover by brazing. Brazing is typically performed by manually applying solder to the top of the blades and then heat treating them at an elevated temperature (i.e., about 1150° C.). A disadvantage of this brazing operation is that it can result in significant deformation of the centrifugal diffuser 20; in particular, it distorts the flatness of the distributor. For example, this brazing operation can produce distortions such as Figure 2 , where the distortion rate may be in the range of + / - 0.2 to + / - 0.5. This deformation of the flatness of the distributor is partly random and therefore uncontrolled. In fact, the radius of the solder formed between the top of the blade and the cover wall is difficult to control and is generally difficult to achieve. Depending on the amount of solder deposited, the solder may spread out on the blade and, due to capillary action, in the radial air flow defined by the diffuser, which may cause the metallographic structure of the diffuser to change outside the assembly area.
[0005] When solder is applied manually, problems with poor solder wetting and / or lack of solder can also occur, which are relatively random and difficult to avoid. The only known way to solve these problems is to perform re-soldering operations, sometimes in large numbers. However, each re-soldering operation requires a complete soldering cycle and therefore a new high-temperature heat treatment. Since heat treatment causes the diffuser to deform, it is understandable that the more heat treatments the diffuser is subjected to, the greater the deformation.
[0006] In order to reduce the risks associated with brazing the blades to the cover, manufacturers of centrifugal diffusers have considered replacing the brazing operation with an electron beam welding operation, which is also called EBW (or EB welding). In fact, the use of EBW will reduce the risk of brazing radius, dripping and wetting. However, EBW requires that parts of different masses, especially parts of different thicknesses, are melted together in a short distance. In fact, the diffuser cover is at least 2 mm thick, while the thickness of the blade top to be welded to the cover is usually between 0.3 mm and 2 mm. Figure 3 An example of a blade profile for a centrifugal diffuser is shown. The example shows that the thickness of the blade is progressive, with a maximum thickness of about 2 mm at the center of the blade and a minimum thickness of about 0.3 mm to 0.5 mm at the end of the blade and therefore at the top of the blade. This difference in mass between the top of the blade and the cover prevents the two areas from melting together, especially when assembling from the outer surface of the cover (i.e., the surface opposite to the surface to which the blade is attached), above which the electron beam is located.
[0007] Another disadvantage arises from the operation of assembling the blade and the cover by EBW. In fact, the assembly between the blade and the cover is traditionally carried out using a brazing technique according to a configuration known as "through blade" and a configuration known as "non-through blade". Figure 5A An example of a through-construction is shown, Figure 5B An example of a non-penetrating configuration is shown. In the penetrating configuration, the top 22a of the blade passes through the cover 21 via a suitable orifice and protrudes from the outer surface 21a of the cover. In the non-penetrating configuration, the top 22a of the blade is positioned against the inner surface 21b of the cover. These two configurations are used together for the same diffuser and have been defined to enable positioning of the cover relative to the blades and to obtain improved mechanical strength at the joint.
[0008] While the through- configuration is suitable for EBW, the non-through- configuration results in electron beam instability, where the electron beam is deflected at the tip of the blade during EBW. Figure 4The electron beam EB during EBW is schematically shown at the junction between the cover 21 and the top 22a of the vane 22 of the diffuser in a non-penetrating configuration. The deflection of the EB electron beam indicated by the arrows on both sides of the top 22a of the vane prevents the assembly of the cover and the vane due to local melting of the material. Therefore, the vane installed in the non-penetrating configuration cannot be attached to the cover by EBW.
[0009] Therefore, a solution for assembling the blades to the diffuser cover by EBW is indeed needed. Summary of the invention
[0010] In view of the problem of assembling blades on a centrifugal diffuser cover discussed above, the applicant provides a high energy fusion welding assembly method (such as EBW), in which the fusion welding beam is guided by grooves formed on the surface of the cover. The applicant also provides an assembly of metal parts obtained by this method.
[0011] According to a first aspect, the invention relates to a method for assembling a first metal component to a second metal component, the first metal component and the second metal component having different masses, characterized in that the method comprises the following operations:
[0012] - forming a groove on the surface of the first metal part,
[0013] - positioning the second metal component to align with the slot in the first metal component, and
[0014] - welding the second metal component to the first metal component with a high energy welding beam through the slot, the slot providing guidance for the welding beam.
[0015] The method enables the metal parts to be assembled by high energy fusion welding technology even when the metal parts have different masses by providing guidance of the fusion welding beam through the slot.
[0016] Throughout the specification, the expression "metal component" includes a metal component and a component formed of an alloy.
[0017] Furthermore, two components are considered to have “different masses” when they have different volumes, sizes and / or thicknesses relative to each other, i.e., the ratio between the thickness of a first metal component (e.g., a cover in the example detailed below) and the thickness of a second metal component (e.g., the thickness of the blade at its thinnest level for the example detailed below where the second metal component is a blade with progressive thickness) is in the range of 1 to 10.
[0018] In addition to the features just discussed in the previous paragraph, the assembly method according to one aspect of the present invention may have one or more of the following complementary features, which may be considered individually or in any technically possible combination:
[0019] - The fusion welding operation comprises electron beam fusion welding.
[0020] - The welding operation includes laser welding.
[0021] The second metal component is positioned relative to the first metal component in a non-penetrating configuration.
[0022] The groove formed during the groove forming operation is a through groove, the shape of which is substantially similar to the contour of the second metal part.
[0023] A second aspect of the invention relates to an assembly of a first metal component and a second metal component obtained by the above method, wherein the first metal component is a centrifugal diffuser cover and the second metal component is a centrifugal diffuser blade, the cover and the blade being assembled by locally melting the metal of the metal cover and the blade.
[0024] A third aspect of the present invention relates to a centrifugal diffuser for a turbine, comprising a metal cover and a plurality of metal blades, wherein the cover has a substantially planar surface and the blades extend substantially perpendicularly to the planar surface of the cover, and wherein each blade is assembled with the cover by the above method.
[0025] In addition to the features just discussed in the preceding paragraphs, the centrifugal diffuser according to one aspect of the present invention may have one or more of the following additional features, which may be considered individually or in any technically possible combination:
[0026] - some of the plurality of blades are assembled with the cover in a through-configuration and other of the plurality of blades are assembled with the cover in a non-through-configuration.
[0027] - Each blade comprises a blade portion assembled with the cover in a through-configuration and a blade portion assembled with the cover in a non-through-configuration.
[0028] - The portion of the blade assembled with the cover in a non-through configuration is located at one end of the blade.
[0029] A fourth aspect of the present invention relates to a turbomachine for an aircraft, the turbomachine comprising a centrifugal diffuser as described above, the centrifugal diffuser being installed at the outlet of a compressor of the turbomachine. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Other advantages and features of the present invention will become apparent from a reading of the following description illustrated by the accompanying drawings, in which:
[0031] Already described Figure 1 A schematic longitudinal cross-sectional view of an example of a turbine according to the prior art is shown.
[0032] Already described Figure 2 A schematic side view and a schematic perspective view of a diffuser according to the prior art are shown, which diffuser is deformed due to the heat treatment of a brazing operation.
[0033] Already described Figure 3 Schematic diagram showing the profile of a diffuser blade according to the prior art
[0034] Already described Figure 4 A schematic cross-sectional view of the cover / vane interface of a diffuser according to the prior art is shown during EBW operation.
[0035] Already described Figure 5A and Figure 5B Schematic cross-sectional views of a cover / vane joint of a diffuser according to the prior art are shown in a through-vane configuration and in a non-through-vane configuration, respectively.
[0036] Figure 6 A schematic cross-sectional view of a cover / vane joint of a diffuser according to the invention is shown prior to fusion welding.
[0037] Figure 7 A schematic perspective view of a diffuser cover according to the invention is shown, wherein the vanes are welded to the cover by high energy welding.
[0038] Figure 8 A schematic cross-sectional view of a blade end fusion welded to a diffuser cover according to the invention is shown.
[0039] Fig. 9 Schematic perspective views of several vanes of a diffuser according to the present invention assembled in a through-configuration and a non-through-configuration are shown.
[0040] Fig.10 A functional diagram showing the assembly method according to the invention is shown.
[0041] Fig.11 A top view and a fragmentary top view of an example of a diffuser according to the invention are shown, the diffuser having a region of non-through construction at the blade tip. DETAILED DESCRIPTION
[0042] Exemplary embodiments of a method for assembling a blade to a diffuser cover by high energy fusion welding and examples of blades and diffuser covers assembled by the method will be described in detail below with reference to the accompanying drawings. These embodiments illustrate the features and advantages of the present invention. However, it should be noted that the present invention is not limited to these examples.
[0043] In the figures, identical elements are denoted by identical reference numerals. For reasons of legibility of the figures, the size ratios between the illustrated elements are not taken into account.
[0044] Generally speaking, fusion welding is a permanent assembly technique that creates a natural continuity between the welded parts. The term fusion welding is used to indicate that the metals or alloys that join the parts to be assembled are formed by melting the edges to be assembled, with or without the addition of filler materials. Thus, fusion welding can be the result of base metal alone (i.e., the parts to be assembled) or a mixture of base metal and filler material. During fusion welding, the parts to be assembled undergo local melting, unlike brazing, where the materials to be assembled do not melt.
[0045] High energy fusion welding (such as electron beam fusion welding or laser fusion welding) is a fusion welding technique in which a high energy fusion welding beam is applied to the parts to be assembled to generate intense heat for melting the metal of the parts to be assembled. The term "high energy" means that the fusion welding beam delivers at least 10 kW / mm 2 High local power. In electron beam welding or EBW, an electron beam bombards the parts to be assembled and generates a narrow, intense three-dimensional heat source to form a hole or tunnel opening through the material of the two parts and travel along the joint to be welded. In laser welding technology, the electron beam is replaced by a laser beam.
[0046] According to the method of the present invention (an example of this method is Fig.10 An example of two metal parts (in particular a blade 22 and a centrifugal diffuser cover 21) to be assembled using the method of the invention is shown in Figure 6 The following description will be given with respect to blades and centrifugal diffuser covers, it being understood that the method of the present invention may be implemented for any assembly of a first metal component with a second metal component.
[0047] In order to allow fusion welding without deflection of the high-energy fusion welding beam, the method according to the present invention comprises a forming operation 110: forming a groove 23 on the outer surface 21a of the cover 21, the groove 23 being positioned facing the blade 22. The groove 23 is an opening passing through the cover 21 in the thickness e of the cover 21. The groove 23 extends on the cover along at least a portion of the contour of the blade 22, and the shape of the groove is roughly similar to the contour; the groove 23 can be, for example, roughly straight or in the shape of a circular arc. Figure 6 In the example of the embodiment of the present invention, the groove 23 is formed to be vertically aligned with the profile of the blade 22 so as to guide the high-energy fusion welding beam toward the top 22a of the blade to be fusion welded, thereby avoiding deflection of the beam. The high-energy fusion welding beam (also called fusion welding beam, electron beam or laser beam) is guided toward the groove 23 and follows the groove along the entire length of the groove 23. Therefore, the fusion welding beam causes the metal of the cover 21 located near the groove 23 and the metal of the blade 22 located facing the groove 23 to locally reach their melting temperature. The two molten metals gather so that the two metal parts are assembled together after cooling.
[0048] The grooves may be formed using techniques conventionally used for cutting metal parts, such as laser cutting or EDM (Electro Discharge Machining) cutting. Figure 7 An example of a centrifugal diffuser cover with several slots is shown. This cover 21 comprises slots 23 formed for implementing the method according to the invention. These slots 23 enable blades (not visible in the figure) to be assembled on the cover 21 in a non-through configuration. Figure 7 Also shown are apertures 24 for assembling the blade in a through configuration, as will be explained later.
[0049] Fig.10 The method comprises, after the operation 110 of forming the slot 23, a positioning operation 120: positioning the blade 22 in alignment with the slot 23. In fact, for the fusion welding beam, in order to ensure the melting of the metal of the cover and the metal of the blade, it is necessary to position the blade facing the slot, wherein the top 22a of the blade extends substantially perpendicularly to the inner surface 21b of the cover 21. Once the blade 22 has been positioned, a high-energy fusion welding operation 130 is performed using suitable fusion welding equipment. As previously described, this fusion welding operation 130 is performed by heating the metal of the top of the blade 22 and the metal of a portion of the cover 21 adjacent to the slot 23 to their melting temperatures, thereby obtaining a fusion zone Z2 that will ensure the assembly of the two parts after cooling.
[0050] In some embodiments, some of the blades 22 are assembled with the cover in a non-through configuration and other blades are assembled with the cover in a through configuration.
[0051] In some other embodiments, the blade 22 is partially assembled with the cover in a through-structure and partially assembled with the cover in a non-through-structure. Fig. 9 shown. Fig. 9 A blade 22 comprising an extension 22b and a conventional portion 22c is shown. The extension 22b is a portion of the blade 22 that protrudes longitudinally from the conventional portion 22c of the blade. The extension 22b is designed to be inserted into the orifice 24 of the cover 21 in a through configuration. These extensions 22b accommodated in the orifice 24 are assembled with the cover 21 by a conventional high-energy fusion welding operation, in which the fusion welding beam causes the melting of the metal of the extension 22b and the metal of the cover around the extension to produce a first fusion zone Z1. The conventional portions 22c of the blade 22 are each positioned against a slot 23 in the cover to align with the slot. The assembly of these conventional zones 22c with the cover 21 is obtained after the fusion welding beam passes through the slot 23, i.e., along the conventional portion 22c of the blade. The fusion welding beam produces a second fusion zone Z2 through the slot 23.
[0052] Thus, as previously described, the slot 23 in the cover 21 makes it possible to direct and focus the fusion welding beam on the top 22a of the blade in the area of the non-through construction. Since this slot 23 is formed facing the conventional portion 22c of the blade 22, it provides additional advantages when positioning the cover. In fact, this slot 23 makes it possible to check whether the positioning of the cover 21 relative to the blade 22 is correct before welding. Several techniques are currently used to check the positioning of the cover relative to the blade (for example using mechanical detection tools or optical tools); the inspection with the help of the slot 23 makes it possible to replace the usual techniques or to confirm the positioning inspection, which has the advantage of being simple to implement and not requiring additional expensive devices.
[0053] As described above, the assembly method by welding through the slot 23 solves the problem caused by the difference in mass between the blade and the cover. In the embodiment where each blade is assembled partially in a through-construction and partially in a non-through-construction, the difference in mass is particularly evident at the tip of the blade (i.e., in the area close to the end of the blade). In fact, at the tip of the blade, the difference in mass not only leads to a difference in the thickness of the parts (the thickness of the blade tip is about 0.2mm to 0.3mm, and the thickness of the cover is about 2mm to 3mm), but also in the transition area when the construction mode is converted from the through-construction to the non-through-construction. In this transition area, the change in construction produces a significant change in thickness, especially when the blade profile is very thin therein. Figure 8An example of assembly of a blade tip is schematically shown in , where the zone Zt is for a through-construction, the zone Znt is for a non-through-construction and the transition zone is Ztrans. In order to avoid variability in the transition zone Ztrans during the fusion welding operation, the method includes an operation of adjusting the positioning of the zone Zt of the through-construction, which must be positioned as close as possible to the edge of the blade 22 in order to make optimal use of the fusion weldability provided by the through-construction. In addition to this adjustment operation, on the contrary, the zone Znt of the non-through-construction is chosen to remain at the blade tip. In Fig.11 A schematic example of a diffuser according to the invention having a non-penetrating zone Znt at the blade tip is shown in FIG. The choice of a zone Znt having a non-penetrating zone at the blade tip avoids many problems. In fact, if the zone Zt having a penetrating zone is located at the very end of the blade 22, then:
[0054] - On the one hand, the welded cap 21 at the top of the blade will have a weakened area on its outer diameter (at Fig.11 The weakened area is circled in the middle, which may deform under the influence of the fusion welding operation. The airflow height defined by the height of the vanes located inside the diffuser will not be controlled on either side of the vanes. In addition, the diffuser cover is deformed in this area; and
[0055] - On the other hand, the use of tools to position the weakened zone in order to keep it in place during the fusion welding operation introduces unnecessary industrial complexity, mainly due to the overall dimensions of the elements involved (blades, covers, blade height, juxtaposition of the blades relative to each other, etc.).
[0056] Keeping the area Znt of non-through construction at the blade tip not only makes it possible to avoid the above-mentioned problems, but also makes it possible to weld the thinnest areas of the blade 22 to ensure that the cover 21 remains in place and to limit the manufacturing costs by avoiding complex implementation.
[0057] Although described through a number of examples, alternatives and embodiments, the assembly method according to the present invention, the assembly itself and the diffuser produced by implementing the method include various alternatives, modifications and improvements, which will be obvious to those skilled in the art and should be understood to be within the scope of the present invention.
Claims
1. A method for assembling a first metal component (21) to a second metal component (22), the first metal component and the second metal component having different masses, the method being characterized in that the second metal component is at least partially assembled with the first metal component in a non-penetrating configuration, and the method comprising the following operations: a) forming (110) a groove (23) on the surface of the first metal component (21), the groove passing through the first metal component in the thickness (e) of the first metal component, b) positioning (120) the second metal component (22) in alignment with the groove (23) of the first metal component in abutment with the groove (23), and c) welding (130) the second metal component (22) to the first metal component (21) using a high energy welding beam through the slot (23), the slot providing guidance for the welding beam.
2. The method according to claim 1, characterized in that The fusion welding operation (130) includes electron beam fusion welding.
3. The method according to claim 1, characterized in that The fusion welding operation (130) includes laser fusion welding.
4. The method according to any one of claims 1 to 3, characterized in that The groove (23) formed during operation a) comprises a shape substantially similar to the profile of the second metal component (22).
5. An assembly of a first metal component and a second metal component obtained by the method according to any one of claims 1 to 4, wherein: The first metal component (21) is a centrifugal diffuser cover, and the second metal component (22) is a centrifugal diffuser blade, and the cover and the blade are assembled by partially melting the metal of the cover and the blade.
6. A centrifugal diffuser for a turbine, the centrifugal diffuser comprising a metal cover (21) and a plurality of metal blades (22), the cover comprising a substantially planar surface, the blades extending substantially perpendicular to the planar surface of the cover, characterized in that: Each blade (22) is assembled with the cover (21) by a method according to any one of claims 1 to 4.
7. The centrifugal diffuser according to claim 6, characterized in that: Some of the plurality of blades (22) are assembled with the cover (21) in a through-structure, and other blades of the plurality of blades are assembled with the cover in a non-through-structure.
8. The centrifugal diffuser according to claim 6, characterized in that Each blade (22) includes a blade portion (22b) assembled with the cover (21) in a through-fitting configuration and a blade portion (22c) assembled with the cover (21) in a non-through-fitting configuration.
9. The diffuser according to claim 8, characterized in that A blade portion (22c) assembled with the cover (21) in a non-penetrating configuration is located at one end of the blade.
10. A turbomachine for an aircraft, comprising a centrifugal diffuser according to any one of claims 6 to 9, mounted at the outlet of a compressor (13) of the turbomachine.