Hollow blade air passage sealing welding method based on vacuum electron beam welding

Abstract

The invention relates to the technical field of electron beam welding, in particular to a vacuum electron beam welding-based hollow blade airway seal welding method, which comprises the following steps of: designing a blade tip process table according to the size of a hollow blade, and processing and preparing the blade tip process table on the blade tip of the hollow blade; a vacuum electron beam is used for conducting seal welding on an air channel of the hollow blade according to a preset air channel seal welding track, and the air channel seal welding track starts from the blade tip process table, passes through the intersection of the air channel and the blade tip and then ends at the blade tip process table; and the blade tip process table is removed, so that the seal welding part is reserved to the blade tip. According to the vacuum electron beam welding method, the reserved air channel of the hollow blade can be welded and blocked, so that the inner cavity of the hollow blade is sealed, meanwhile, the internal vacuum state is formed, the welding quality stability is good, the strength and fatigue performance of the sealing and welding part are high, and air vibration in the cavity of the hollow blade is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of electron beam welding, and in particular to a hollow blade airway sealing method based on vacuum electron beam welding. Background Art

[0002] In order to achieve blade weight reduction, more and more aircraft engines are beginning to use hollow blades, especially in the compressor fan of turbofan engines, where hollow blades are widely used. Diffusion welding technology is mainly used to prepare hollow blades. Based on the characteristics of this technology, after the hollow blades are prepared, an airway structure will inevitably be left on the edge of the blade, which will connect the blade cavity to the external atmosphere. At present, most of the hollow blades prepared in China have not been post-processed for the airway structure. However, since the open airway will produce local air vibration during the rotation of the blade, and foreign objects may enter when the blade is stationary, in order to ensure the structural integrity and avoid the airway opening becoming a weak link in the blade, foreign companies need to block the airway when preparing hollow blades. The methods used mainly include arc welding, argon arc welding, plasma welding and other manual welding methods.

[0003] At present, the main problems of the commonly used airway sealing methods are: it relies on manual operation, has a strong reliance on the skill level of the operator, and has poor process quality stability; the heat input of manual welding is difficult to stably control, the resulting microstructure has poor uniformity, and is prone to cracks under normal working conditions, eventually causing fatigue fracture; because the sealing is completed in the atmospheric environment, the inner cavity of the hollow blade is filled with air. When the blade rotates under working conditions, the air inside may produce certain vibrations. For rotating parts, such vibrations will have an adverse effect on the dynamic balance of the structure. Summary of the invention

[0004] (1) Technical issues to be solved

[0005] The present application provides a hollow blade airway sealing method based on vacuum electron beam welding, which solves the problems of poor welding quality stability, insufficient strength and fatigue performance of the sealing part, and air vibration in the cavity when the hollow blade is sealed by conventional sealing methods.

[0006] (2) Technical solution

[0007] The present application provides a hollow blade airway sealing welding method based on vacuum electron beam welding, comprising:

[0008] Designing a blade tip process platform according to the size of the hollow blade, and processing and preparing the blade tip process platform on the blade tip of the hollow blade;

[0009] Using a vacuum electron beam to seal the airway of the hollow blade according to a preset airway sealing trajectory, wherein the airway sealing trajectory starts from the blade tip process station, passes through the intersection of the airway and the blade tip, and ends at the blade tip process station;

[0010] The blade tip process station is removed so that the sealing welding position is retained at the blade tip.

[0011] Furthermore, the dimension of the blade tip process platform along the radial direction of the blade is within a first preset range, and the dimension of the blade tip process platform along the blade chord direction and the direction perpendicular to the blade is the same as the blade body dimension of the hollow blade.

[0012] Furthermore, the airway sealing trajectory includes multiple arc segments, and the connecting parts of the arc segments are tangent.

[0013] Furthermore, it also includes:

[0014] The hollow blade is mounted on a pre-prepared airway sealing fixture, so that the position of the hollow blade to be sealed is parallel to the electron gun mounting surface and perpendicular to the electron beam.

[0015] Furthermore, the air duct sealing and welding fixture comprises a tenon stopper, a tenon support plate, a blade support plate, a blade tip support plate, a beam shielding plate support plate and a bottom plate;

[0016] The tenon limit block is used to limit the displacement of the hollow blade, the tenon support plate, the blade body support plate and the blade tip support plate are used to support the hollow blade, and the beam shielding plate support plate is used to place the beam shielding plate.

[0017] Furthermore, the shapes of the tenon support plate, the blade body support plate and the blade tip support plate are the same as the shapes of the corresponding positions of the hollow blade.

[0018] Further, the method of sealing the airway of the hollow blade by using a vacuum electron beam according to a preset airway sealing trajectory includes:

[0019] Determine welding process parameters, use the same parameters to perform multiple sealing welding passes, and the centers of adjacent sealing welding passes are separated by a second preset range, so that the internal molten width of the weld is greater than a preset value.

[0020] Furthermore, the sealing welding of the air passage of the hollow blade adopts the process methods of penetration welding and modification welding.

[0021] Furthermore, the same airway sealing welding track is welded twice, the first time with 50% energy and the second time with 100% energy.

[0022] Furthermore, the process parameters for sealing welding using a vacuum electron beam include: an acceleration voltage of 60 to 150 kV, a focusing current of 20 to 100 mA below the surface focus, and a welding speed of 10 to 20 mm / s.

[0023] (3) Beneficial effects

[0024] The above technical solution of the present application has the following advantages:

[0025] The hollow blade airway sealing method based on vacuum electron beam welding provided in the present application can weld and seal the reserved airway of the hollow blade by using the vacuum electron beam welding method, so as to achieve the closure of the inner cavity of the hollow blade and form an internal vacuum state at the same time. On the one hand, electron beam welding is a welding method that uses numerical control equipment and program control, with high precision, good controllability and guaranteed quality; on the other hand, the hollow blade seals the airway under a vacuum environment, which reduces the air inside the blade as much as possible, reduces the problem of rotational imbalance under working conditions, and at the same time, a higher vacuum degree can also play a good role in improving the welding quality. The welding quality is stable, the strength and fatigue performance of the sealing part are high, and the occurrence of air vibration in the hollow blade cavity is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 Schematic diagram of blade tip position provided for this application;

[0028] Figure 2 Schematic diagram of the airway sealing trajectory provided for this application;

[0029] Figure 3 Schematic diagram of the blade airway sealing welding tooling provided for this application;

[0030] Figure 4 A schematic diagram of the removal of the process platform at the blade tip provided for this application;

[0031] Figure 5 A schematic diagram of an embodiment of hollow blade airway sealing welding provided in this application;

[0032] Figure 6 Schematic diagram of the tenon, blade body and blade tip support plate provided for this application;

[0033] Figure 7Schematic diagram of the blade and airway sealing and welding assembly provided for this application.

[0034] Figure numerals: 1. blade body; 2. blade tip; 3. blade tip process table; 4. air duct sealing track; 5. air duct; 6. blade body cavity; 7. tenon limit block; 8. tenon support plate; 9. blade body support plate; 10. blade tip support plate; 11. beam shielding plate support plate; 12. bottom plate. DETAILED DESCRIPTION

[0035] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0036] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0037] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0038] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. "Multiple" means "two or more".

[0039] In order to solve the problems of poor welding quality stability, insufficient strength and fatigue performance of the sealed part, and air vibration in the cavity when hollow blades are sealed by conventional sealing methods, this application proposes a hollow blade air duct sealing method based on vacuum electron beam welding. This method can effectively improve the strength and reliability of the tip seal. At the same time, electron beam welding has high precision, high degree of automation, and low pollution, which is of great significance for improving production efficiency.

[0040] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but are not intended to limit the scope of the present application.

[0041] The embodiment of the present application provides a hollow blade air duct sealing method based on vacuum electron beam welding, comprising: designing a blade tip process table according to the size of the hollow blade, and processing and preparing the blade tip process table on the blade tip of the hollow blade; using a vacuum electron beam to seal the air duct of the hollow blade according to a preset air duct sealing trajectory, wherein the air duct sealing trajectory starts from the blade tip process table and ends at the blade tip process table after passing through the intersection of the air duct and the blade tip; removing the blade tip process table so that the sealing portion is retained at the blade tip.

[0042] By using the vacuum electron beam welding method to complete the airway sealing, the reserved airway of the hollow blade can be welded and sealed, so as to achieve the closure of the inner cavity of the hollow blade and form an internal vacuum state at the same time. On the one hand, electron beam welding is a welding method that uses CNC equipment and program control, with high precision, good controllability and guaranteed quality; on the other hand, the airway of the hollow blade is sealed in a vacuum environment, which reduces the air inside the blade as much as possible and reduces the problem of rotational imbalance under working conditions. At the same time, a higher vacuum degree can also play a good role in improving the welding quality. The welding quality is stable, the strength and fatigue performance of the sealing part are high, and the occurrence of air vibration in the hollow blade cavity is avoided.

[0043] In some embodiments, the dimension of the blade tip process platform along the radial direction of the blade is within a first preset range, and the dimension of the blade tip process platform along the blade chord direction and the direction perpendicular to the blade is the same as the blade body dimension of the hollow blade.

[0044] In some embodiments, the airway sealing trajectory includes multiple arc segments, and the connecting parts of the arc segments are tangent.

[0045] In some embodiments, the method further includes: installing the hollow blade on a pre-prepared airway sealing fixture so that the position of the hollow blade to be sealed is parallel to the electron gun mounting surface and perpendicular to the electron beam.

[0046] In some embodiments, the air duct sealing and welding fixture includes a tenon limit block, a tenon support plate, a blade body support plate, a blade tip support plate, a beam shielding plate support plate and a base plate; the tenon limit block is used to limit the displacement of the hollow blade, the tenon support plate, the blade body support plate and the blade tip support plate are used to support the hollow blade, and the beam shielding plate support plate is used to place the beam shielding plate.

[0047] In some embodiments, the shapes of the tenon support plate, the blade body support plate and the blade tip support plate are the same as the shapes of the corresponding positions of the hollow blade.

[0048] In some embodiments, the use of a vacuum electron beam to seal the air duct of the hollow blade according to a preset air duct sealing trajectory includes: determining welding process parameters, using the same parameters to perform multiple sealing passes, and the centers of adjacent sealing passes are separated by a second preset range, so that the internal weld width of the weld is greater than a preset value.

[0049] In some embodiments, the sealing welding of the air passage of the hollow blade adopts the process methods of penetration welding and modification welding.

[0050] In some embodiments, the same airway sealing track is welded twice, the first welding is performed with 50% energy, and the second welding is performed with 100% energy.

[0051] In some embodiments, the process parameters for sealing welding using a vacuum electron beam include: an acceleration voltage of 60 to 150 kV, a focusing current of 20 to 100 mA below the surface focus, and a welding speed of 10 to 20 mm / s.

[0052] For the hollow blades and their airway structure, the airway sealing trajectory and blade tip process table structure that conform to the electron beam welding process are first designed; then, based on the shape of the hollow blade and in conjunction with the airway sealing trajectory, a reasonable welding fixture is designed; then, appropriate process methods and parameters are designed to implement airway sealing; after completing the airway sealing, the process table is cut off along the blade tip, and the airway sealing weld is divided into two, one part of which will remain at the blade tip to achieve the sealing of the hollow blade airway.

[0053] Since the weld microstructure is quite different from the parent material, in order to avoid the resulting mechanical property differences and other problems, the air duct sealing process should be designed based on the principle that the weld accounts for as small a proportion of the blade as possible. Figure 1 As shown, since the air duct 5 is located at the blade tip 2, a blade tip process table 3 needs to be designed outside the blade tip 2, and then the electron beam welding method is used to weld along the air duct sealing track 4, that is, the welding track starts from the blade tip process table 3, passes through the junction of the blade tip 2 and the air duct 5, and finally ends at the blade tip process table 3. Since a large area of ​​the process table will cause the cost of raw materials to rise, therefore, considering the economy, the width of the process table, that is, the radial dimension h of the blade, should not be too large. The dimension of the blade tip process table along the radial direction of the blade is within the first preset range, generally 15mm≤h≤50mm; the thickness, that is, the dimension in the vertical direction of the blade, and the length, that is, the dimension along the chord direction of the blade, generally follow the size of the blade body 1.

[0054] Limited by the width of the process table and in order to ensure the stability of the airway sealing process, the sealing track should be as long and smooth as possible. Figure 2 The sealing welding track shown can realize a sufficiently long and smooth sealing welding track in a process table with limited width. The track is mainly composed of arcs S1 to S3, and there is no obvious angle at the connection of each arc to ensure the stability of the molten pool during electron beam welding.

[0055] Since the electron gun is usually fixed on the top or side wall of the vacuum chamber, in order to ensure the stability of the welding process, the position to be sealed should be parallel to the electron gun installation surface and perpendicular to the electron beam. Taking the electron gun installed on the top of the vacuum chamber as an example, the gas channel sealing fixture is as follows: Figure 3 As shown, it is composed of a tenon stopper 7, a tenon support plate 8, a blade support plate 9, a blade tip support plate 10, a beam shielding plate support plate 11 and a bottom plate 12. Among them, the tenon stopper 7 is used to limit the displacement of the blade along the X direction; the tenon support plate 8, the blade support plate 9 and the blade tip support plate 10 have the same shape as the shape of the corresponding position of the blade, the purpose is to ensure that the tooling can effectively support the blade, and a stopper can be set at the edge of the support plate to limit the sliding of the blade on the support plate; the beam shielding plate support plate 11 is mainly used to place the beam shielding plate to prevent the residual energy generated after the electron beam penetrates the parts from burning the tooling.

[0056] Since the sealing welding and subsequent machining of the blade will produce a certain degree of deformation, in order to ensure that the sealing weld can be left at the blade tip as much as possible after the blade tip is processed, the internal molten width of the weld is generally greater than a preset value to determine the welding process parameters. Conventional single-pass welding can be used, and a multi-pass sealing process can be used to further increase the molten width. The centers of adjacent sealing welds are separated by a second preset range such as 1-3mm, that is, after completing a sealing, move 1-3mm along the blade body direction, and seal again with the same parameters, and so on, so that the internal molten width of the weld is greater than the preset value such as 3mm; since the airway structure is equivalent to prefabricated pores in dense metal, this type of structure is very prone to internal pore defects and weld surface collapse during welding, so the process method of penetration welding + modification welding is adopted.

[0057] In terms of process parameters, the acceleration voltage can be selected from 60 to 150 kV, the focusing current can be selected from 20 to 100 mA below the surface focus, the welding beam current is mainly determined by the welding thickness and the formation of the penetration weld, the welding speed can be selected from a medium speed of 10 to 20 mm / s, and the deflection scan can be appropriately increased, so that the pores in the welding process can have sufficient time to escape from the molten pool; in order to further ensure the quality of the weld, the same sealing welding track can be welded twice, that is, the first welding with 50% energy and the second welding with 100% energy, which is conducive to reducing the fluctuation of the welding molten pool caused by the existence of the airway structure and the influence of the solder stopper, resulting in poor weld formation. Figure 4As shown, the excess at the blade tip is removed by machining, including the excess in the process table and blade tip thickness directions, so that the sealing welding part is retained to the blade tip and the rest of the part is removed.

[0058] The following is described by means of specific examples.

[0059] Example

[0060] Take the air duct sealing welding of a certain type of hollow fan blade as an example. Figure 5 As shown. The tip length of the blade is 400mm, the cross-sectional size of the airway to be sealed is 2mm×1mm, and the total thickness of the part to be sealed is about 5mm. The specific steps are as follows: First, design a process table with a thickness of 5-6mm, a width of 40mm, and the same length as the blade tip, and perform processing on the hollow blade to prepare the process table. Design an airway sealing trajectory with a total length of 160mm and three smoothly connected arcs of R=53mm, so that the trajectory starts at the process table, passes through the intersection of the airway and the blade tip, and finally ends at the process table. Then, according to the path coordinates, write the electron beam welding trajectory program.

[0061] Design blade airway sealing welding tooling, structure see Figure 3 The tooling has an overall size of 960mm×600mm and is composed of a tenon stopper, a tenon support plate, a blade support plate, a blade tip support plate, a beam shielding plate support plate and a bottom plate. The shapes of the tenon support plate, the blade support plate and the blade tip support plate are the same as those of the corresponding positions of the blades, and two limit blocks are designed at both ends of the support plate. See the schematic diagram. Figure 6 . Place the parts on the fixture, and place the tenon against the limit block. Figure 7 As shown. The process method of penetration welding + modification welding was selected, and two welding methods were adopted, that is, the first welding was performed with 50% energy, and the second welding was performed with 100% energy; the welding process parameters were as follows: acceleration voltage 150kV, focusing current 2400mA, welding beam 30mA, welding speed 15mm / s. Finally, the process table was removed by mechanical processing.

[0062] The hollow blade air duct sealing method based on vacuum electron beam welding provided in the embodiment of the present application first designs a reasonable air duct sealing trajectory and a blade tip process table structure, and then designs a reasonable welding tooling fixture based on the shape of the hollow blade and in conjunction with the air duct sealing trajectory; then designs appropriate process methods and parameters to implement air duct sealing; after completing the air duct sealing, the process table is cut off along the blade tip, and the air duct sealing weld is divided into two, one part of which will remain at the blade tip to achieve the sealing of the hollow blade air duct.

[0063] The improvements of this method are mainly in five aspects: (1) The electron beam welding equipment is equipped with a high-precision CNC machine tool and an accurate electron beam control system, so it has good guarantees in terms of processing accuracy and processing quality; (2) The hollow blade is sealed and welded in a vacuum environment, which reduces the air inside the blade as much as possible and reduces the problem of rotational imbalance under working conditions. At the same time, the vacuum environment can also effectively improve the welding quality; (3) For the airway structure, a sealing trajectory formed by multiple arc connections and a reasonable process table design can ensure that the molten pool is always in a stable state during the sealing process; (4) The process method of two welding and penetration welding + modification welding can further increase the probability of pores in the weld to escape and improve the weld quality; (5) The tooling fixture in this method can ensure the effective support of the parts, so that the surface to be sealed is perpendicular to the electron beam, simplifying the difficulty of adjusting the process parameters during the sealing process and improving work efficiency.

[0064] It should be clear that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. The present application is not limited to the specific structures described above and shown in the figures. In addition, for the sake of simplicity, detailed descriptions of known methods and technologies are omitted here.

[0065] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A hollow blade airway sealing method based on vacuum electron beam welding, characterized in that: include: Designing a blade tip process platform according to the size of the hollow blade, and processing and preparing the blade tip process platform on the blade tip of the hollow blade; Using a vacuum electron beam to seal the airway of the hollow blade according to a preset airway sealing trajectory, wherein the airway sealing trajectory starts from the blade tip process station, passes through the intersection of the airway and the blade tip, and ends at the blade tip process station; The blade tip process station is removed so that the sealing welding position is retained at the blade tip.

2. The hollow blade airway sealing method based on vacuum electron beam welding according to claim 1, characterized in that: The dimension of the blade tip process platform along the radial direction of the blade is within a first preset range, and the dimension of the blade tip process platform along the blade chord direction and the direction perpendicular to the blade is the same as the blade body dimension of the hollow blade.

3. The hollow blade airway sealing method based on vacuum electron beam welding according to claim 1, characterized in that: The airway sealing welding trajectory includes multiple arc segments, and the connecting parts of the arc segments are tangent.

4. The hollow blade airway sealing method based on vacuum electron beam welding according to claim 1, characterized in that: Also includes: The hollow blade is mounted on a pre-prepared airway sealing fixture, so that the position of the hollow blade to be sealed is parallel to the electron gun mounting surface and perpendicular to the electron beam.

5. The hollow blade airway sealing method based on vacuum electron beam welding according to claim 4, characterized in that: The air duct sealing and welding fixture comprises a tenon limit block, a tenon support plate, a blade body support plate, a blade tip support plate, a beam shielding plate support plate and a bottom plate; The tenon limit block is used to limit the displacement of the hollow blade, the tenon support plate, the blade body support plate and the blade tip support plate are used to support the hollow blade, and the beam shielding plate support plate is used to place the beam shielding plate.

6. The hollow blade airway sealing method based on vacuum electron beam welding according to claim 5, characterized in that: The shapes of the tenon support plate, the blade body support plate and the blade tip support plate are the same as the shapes of the corresponding positions of the hollow blade.

7. The hollow blade airway sealing method based on vacuum electron beam welding according to claim 1, characterized in that: The method of sealing the air passage of the hollow blade by using a vacuum electron beam according to a preset air passage sealing trajectory comprises: Determine welding process parameters, use the same parameters to perform multiple sealing welding passes, and the centers of adjacent sealing welding passes are separated by a second preset range, so that the internal molten width of the weld is greater than a preset value.

8. The hollow blade airway sealing method based on vacuum electron beam welding according to claim 1, characterized in that: The sealing welding of the air passage of the hollow blade adopts the process methods of penetration welding and modification welding.

9. The hollow blade airway sealing method based on vacuum electron beam welding according to claim 1, characterized in that: The same airway sealing welding track is welded twice, the first time with 50% energy and the second time with 100% energy.

10. The hollow blade airway sealing method based on vacuum electron beam welding according to claim 1, characterized in that: The process parameters for sealing welding using a vacuum electron beam include: an acceleration voltage of 60 to 150 kV, a focusing current of 20 to 100 mA below the surface focus, and a welding speed of 10 to 20 mm / s.

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