A process design method for diffusion welding joint of hollow adjustable blade surface

Abstract

The present invention relates to the technical field of manufacturing adjustable blades for aircraft engines, and specifically to a process design method for a hollow adjustable blade curved surface diffusion welding joint. Based on the inner and outer surface features of the hollow adjustable blade, by supplementing entities, extending surfaces, offsetting parting surfaces, and trimming large curvature surfaces, the specific data include the height range of the solid phase diffusion welding joint before welding, the range of the extended surface, the position of the trimmed large curvature surface, the offset size and tolerance of the parting surface, and the requirements for numerical control processing, etc., which greatly reduces the difficulty of solid phase diffusion welding and numerical control processing, comprehensively improves the quality of the curved surface solid phase diffusion welding joint and the precision of numerical control processing, and adopts the joint design method provided by the present invention to realize the manufacturing of adjustable blade parts and the assessment of the whole machine, meeting the design indicators and quality reliability requirements. The present invention is based on diffusion welding technology, and on the basis of ensuring quality reliability, solves a series of technical bottlenecks that plague the manufacturing of hollow adjustable blades.

Description

Technical Field

[0001] The invention relates to the technical field of manufacturing adjustable blades of aircraft engines, in particular to a process design method for a hollow adjustable blade curved surface diffusion welding joint. Background Art

[0002] like Figure 5 As shown, the adjustable blade 3 is a precision component for adjusting the intake volume at the intake end of the aircraft engine. It is precisely matched with the straightening blade 4 to achieve very small intake leakage loss and prevent surge. At the same time, the weight of the engine can be further reduced by lightweight structural design. The adjustable blade of a certain aircraft engine is designed as a hollow structure. Compared with the mainstream solid adjustable blade structure, its structural rigidity and bearing strength are greatly reduced. The complex working conditions of high flow rate and large load and higher aerodynamic adjustment requirements make the hollow adjustable blade extremely demanding in terms of quality reliability, and accordingly put forward higher requirements for component quality, organizational performance, processing accuracy and manufacturing compliance.

[0003] The superplastic forming / diffusion bonding (SPF / DB) process was once used in China to manufacture hollow adjustable blades. However, due to problems such as hot forming process stability, dimensional accuracy and quality reliability, it has been difficult to achieve engineering application. Summary of the invention

[0004] The purpose of the present invention is to provide a process design method for a hollow adjustable blade curved surface diffusion welding joint, which is based on the split structure diffusion welding technology and solves a series of technical bottlenecks that plague the manufacture of hollow adjustable blades on the basis of ensuring quality reliability.

[0005] The technical solution of the present invention is:

[0006] A process design method for a hollow adjustable blade curved surface diffusion welding joint is based on the inner and outer surface features of the hollow adjustable blade, and is designed by supplementing entities, extending surfaces, offsetting parting surfaces, and trimming large curvature surfaces. Specific data include the height range of the solid phase diffusion welding joint before welding, the range of extended surfaces, the position of trimmed large curvature surfaces, the offset size and tolerance of the parting surfaces, and CNC machining requirements.

[0007] The process design method of the hollow adjustable blade curved surface diffusion welding joint comprises the following steps:

[0008] Step 1: Parting surface structure analysis

[0009] The solid phase diffusion welding parting surface of the hollow adjustable blade before welding takes the shaft neck parting surface as the reference plane, extends along the split parting surface to the blade body to the outermost hollow area, and then extends at least 30mm in the direction parallel to the reference plane, and at least 15mm is added in the width direction of the other side; in the length direction of the solid phase diffusion welding parting surface, the shaft neck length is included, and at least 15mm is added for each; in the height direction of the solid phase diffusion welding parting surface, the ratio of the total compression to the total height is not more than 1.5%, and the total compression takes into account the maximum curvature of the parting surface and the quality assurance of the solid phase diffusion welding, and the total compression is preset to be 0.5mm;

[0010] Step 2: Curved Diffusion Welded Joint Structure

[0011] In the structure of the curved diffusion welding joint, length × width × height = 420mm × 125mm × 38.50mm, a solid phase diffusion welding compression amount of 0.25mm is reserved for each piece along the profile surface, the profile contour is not greater than 0.05, the surface roughness is not greater than 1.6μm, Φ12mm fine holes are reserved at both ends along the length direction for solid phase diffusion welding assembly positioning, Φ12mm positioning holes are reserved in the middle of the length direction for auxiliary assembly positioning, Φ6mm fine holes are reserved at both ends along the length direction for post-weld CNC machining positioning, and inspection steps are reserved along the circumference for machining parting surface inspection and processing of adjustable blade surface fine-tuning.

[0012] The process design method of the hollow adjustable blade curved surface diffusion welding joint is that the sweep angle of the hollow adjustable blade gradually increases along the split parting surface, the maximum downward sweep angle relative to the shaft neck parting surface is 29.4 degrees, the maximum upward sweep angle is 11.5 degrees, the maximum height of the adjustable blade is 20.0 mm from the tip of the maximum downward sweep angle of the parting surface to the upper surface of the shaft neck, and the hollow area is 15 mm away from the edge of the adjustable blade.

[0013] The process design method of the hollow adjustable blade curved surface diffusion welding joint is as follows: the superimposed structure of the adjustable blade split parting surface and the solid phase diffusion welding interface is as follows: the upper sweep angle of the part protrudes from the pre-welding workpiece entity, and the lower sweep angle of the part enters the pre-welding workpiece entity. An asymmetric structure is adopted in the process design of the diffusion welding joint to transfer the position with large curvature at the sweep angle to the matching half entity.

[0014] The process design method of the hollow adjustable blade curved surface diffusion welding joint is to form a hollow adjustable blade as a whole after assembly and diffusion welding, wherein:

[0015] Two upper profile assembly positioning holes are arranged in the middle of both sides in the longer direction of the upper profile, and one upper profile passing positioning hole is arranged on one side in the shorter direction of the upper profile; in addition, two upper profile post-welding processing reference holes are arranged on both side edges in the longer direction of the upper profile; two lower profile assembly positioning holes are arranged in the middle of both sides in the longer direction of the lower profile, and one lower profile passing positioning hole is arranged on one side in the shorter direction of the lower profile, which is conducive to ensuring accurate assembly; in addition, two lower profile post-welding processing reference holes are arranged on both side edges in the longer direction of the lower profile.

[0016] The process design method of the hollow adjustable blade curved surface diffusion welding joint is as follows: after pickling, cleaning and ultrasonic cleaning before welding, the upper and lower halves of the hollow adjustable blade are assembled and fixed with positioning pins, and a fixed limit block is used to preset a 0.5mm compression amount and enter the furnace for diffusion welding.

[0017] The design concept of the present invention is:

[0018] The present invention is based on diffusion welding technology, and on the basis of ensuring quality reliability, proposes a process design method for curved surface diffusion welding joints, which solves a series of technical bottlenecks that plague the manufacturing of hollow adjustable blades. The process design method for curved surface diffusion welding joints of hollow adjustable blades of the present invention is based on the internal and external surface characteristics of hollow adjustable blades, and through methods such as supplementing entities, extending surfaces, offsetting parting surfaces, and trimming large curvature surfaces. The specific data include the height range of the solid phase diffusion welding joint before welding, the extended surface range, the position of the trimmed large curvature surface, the offset size and tolerance of the parting surface, and the requirements for numerical control processing, etc., which greatly reduces the difficulty of solid phase diffusion welding and numerical control processing, and comprehensively improves the quality of curved surface solid phase diffusion welding joints and the precision of numerical control processing. The joint design method provided by the present invention has realized the manufacturing of adjustable blade parts and the assessment of the whole machine, and meets the design indicators and quality reliability requirements.

[0019] The beneficial effects brought about by the technical solution of the present invention are:

[0020] 1. The present invention is used for the design of diffusion welding joints of curved surface structures, which is suitable for the lightweight design and manufacturing of hollow adjustable blade structures of aircraft engines. It has a series of advantages such as simplified design structure, excellent processing technology and high quality stability. It has high added value in the application end technology and huge market potential. At the same time, it is also applicable to other components with complex internal structures that involve high precision, high quality and high reliability.

[0021] 2. The application of the technical achievements of the present invention has completed the manufacture of multiple sets of hollow adjustable blade products in large quantities, with a diffusion welding joint welding rate of more than 98%, and its tensile and endurance performance can reach more than 95% of the parent material. The fatigue limit of the diffusion welding joint and the thermal cycle parent material rotation bending reaches 480MPa. Through component assessment, stress testing and whole machine assessment, it meets the requirements of various design assessment indicators, the dynamic strength reserve coefficient is higher than the design value, and the manufacturing compliance, quality stability and organizational performance reliability are significantly improved.

[0022] 3. The present invention can also be extended to the process design of diffusion welding joints of various complex curved surface structures, unequal cross-sections and complex curved surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Parts diagram (half) of the hollow adjustable blade at two different angles on the left and right.

[0024] Figure 2 This is a design position diagram where the split parting surface of the adjustable blade and the solid-phase diffusion welding interface do not overlap at the position with a larger curvature. The upper figure is the upper half of the split parting surface, and the lower figure is the lower half of the split parting surface.

[0025] Figure 3(a) is a diagram of the hollow adjustable blade before welding (half 1).

[0026] Figure 3(b) is a diagram of the hollow adjustable blade before welding (half 2).

[0027] Figure 4 This is a cross-sectional view (half) of the processing dimensions before welding in step 2 of the embodiment.

[0028] Figure 5 Schematic diagram of the precise matching of hollow adjustable blades and rectifying blades.

[0029] Numbers in the figure: 1 upward sweep angle, 2 downward sweep angle, 3 adjustable blades, 4 straightening blades, 5 upper profile assembly positioning hole, 6 upper profile passing positioning hole, 7 upper profile post-welding processing reference hole, 8 lower profile assembly positioning hole, 9 lower profile passing positioning hole, 10 lower profile post-welding processing reference hole. DETAILED DESCRIPTION

[0030] In a specific implementation process, the present invention proposes a process design method for a hollow adjustable blade curved surface diffusion welding joint, comprising the following steps:

[0031] Step 1: Parting surface structure analysis

[0032] like Figure 1As shown in the figure, the sweep angle of the hollow adjustable blade gradually increases along the split parting surface, the maximum downward sweep angle 2 is 29.4 degrees (relative to the journal parting surface), the maximum upward sweep angle 1 is 11.5 degrees, the maximum height of the adjustable blade is 20.0mm from the tip of the maximum downward sweep angle of the parting surface to the upper surface of the journal, and the hollow area is 15mm away from the edge of the adjustable blade. If the split parting surface of the adjustable blade is a solid phase diffusion welding interface, the maximum sweep angle will affect the solid phase diffusion welding pressure and compression, and too large an angle will directly affect the quality of the solid phase diffusion welding joint. At the same time, based on the influence of the solid phase diffusion welding fish mouth defect or edge effect on the quality of solid phase diffusion welding, it is necessary to extend at least 15mm in two directions along the plane based on the original interface of solid phase diffusion welding, which will directly lead to an increase in thickness and an increase in the sweep angle at the extension, which will have an adverse effect on material utilization and solid phase diffusion welding quality.

[0033] In summary, the solid phase diffusion welding parting surface of the hollow adjustable blade before welding takes the shaft neck parting surface as the reference plane, extends along the split parting surface to the blade body to the outermost hollow area, and then extends at least 30mm in the direction parallel to the reference plane, and at least 15mm is added in the width direction of the other side; in the length direction of the solid phase diffusion welding parting surface, the shaft neck length is included, and at least 15mm is added for each; in the height direction of the solid phase diffusion welding parting surface, the ratio of total compression to total height is not more than 1.5%, and the total compression takes into account the maximum curvature of the parting surface and the quality assurance of solid phase diffusion welding, and the total compression is preset to 0.5mm.

[0034] like Figure 2 As shown, the superimposed structure of the adjustable blade split parting surface and the solid phase diffusion welding interface is as follows: the position shown by coil A is the upper swept angle of the part protruding from the pre-welding workpiece entity, and the coil B is the lower swept angle of the part entering the pre-welding workpiece entity. The split structure of the adjustable blade part adopts a completely symmetrical type, which makes the curvature at the swept angle too large, which easily causes the partial pressure at the position with large curvature to be too small during diffusion welding, forming an unwelded defect, and the machinability of the position with large curvature is also poor. Therefore, an asymmetric structure is adopted in the process design of the diffusion welding joint, and the position with large curvature at the swept angle is transferred to the matching half entity, which better solves the above problems. At the same time, it is also beneficial to reduce the thickness of the pre-welding workpiece, thereby realizing the refinement of the rough material and reducing the rough material cost.

[0035] Step 2: Curved Diffusion Welded Joint Structure

[0036] like Figure 2As shown in the figure, in the structure of the curved diffusion welding joint, length × width × height = 420mm × 125mm × 38.50mm (total height after buckling), 0.25mm of solid phase diffusion welding compression is reserved for each piece along the profile surface, the profile contour is not more than 0.05, the surface roughness is not more than 1.6μm (local polishing is allowed), Φ12mm fine holes are reserved at both ends of the length direction for solid phase diffusion welding assembly positioning, Φ12mm positioning holes are reserved in the middle of the length direction for auxiliary assembly positioning, Φ6mm fine holes are reserved at both ends of the length direction for CNC machining positioning after welding, and inspection steps are reserved along the circumference for machining parting surface inspection and processing of adjustable blade surface fine adjustment.

[0037] Depend on Figure 3(a)-Figure 3(b) It can be seen that the figure shows the view of the two half-profiles, and the hollow adjustable blade is formed as a whole after assembly and diffusion welding. As shown in Figure 3 (a), the upper half profile assembly positioning holes 5 (two) are set in the middle of the two sides in the longer direction of the upper half profile, and the upper half profile passing positioning hole 6 (one) is set on one side of the shorter direction of the upper half profile, which is conducive to ensuring accurate assembly; in addition, the upper half profile post-welding processing reference holes 7 (two) are set on the two side edges in the longer direction of the upper half profile, which is conducive to ensuring the precise positioning of the post-welding combined processing. As shown in Figure 3 (b), the lower half profile assembly positioning holes 8 (two) are set in the middle of the two sides in the longer direction of the lower half profile, and the lower half profile passing positioning hole 9 (one) is set on one side of the shorter direction of the lower half profile, which is conducive to ensuring accurate assembly; in addition, the lower half profile post-welding processing reference holes 10 (two) are set on the two side edges in the longer direction of the lower half profile, which is conducive to ensuring the precise positioning of the post-welding combined processing. During assembly, the upper profile assembly positioning hole 5 corresponds to the lower profile assembly positioning hole 8, the upper profile passing positioning hole 6 corresponds to the lower profile passing positioning hole 9, and the upper profile post-weld processing reference hole 7 corresponds to the lower profile post-weld processing reference hole 10.

[0038] Below, the present invention is further described in detail by examples.

[0039] Example

[0040] In this embodiment, a process design method for a hollow adjustable blade curved surface diffusion welding joint is as follows:

[0041] Step 1: Forging blank and size

[0042] TC4 alloy die forging blank is used and annealed at 780℃. Its typical structure is composed of primary α phase and (α+β) lamellar structure. The primary α phase is controlled at 20% to 30%. The effective net size of the blank is 420×135×25mm.

[0043] Step 2: Pre-welding processing and dimensions

[0044] Main processing steps: milling plane and periphery - fine-tune the benchmark - rough / fine milling welding surface (reserve machining allowance) - corrosion inspection - fine milling welding surface and positioning hole (reserve welding compression) - milling cavity - final inspection - fluorescent inspection - cleaning - packaging and storage. The specific size requirements of the upper half of the surface after processing can be found in Figure 4 .

[0045] Step 3: Diffusion welding

[0046] After pickling, cleaning and ultrasonic cleaning before welding, the upper and lower surfaces are assembled and fixed with locating pins. A fixed limit block is used to preset a compression amount of 0.5 mm and then the parts are put into the furnace for diffusion welding. The height values ​​are recorded before and after welding.

[0047] Step 4: Assembly processing

[0048] The main processes include reaming locating holes - repairing peripheral datums (process tables) - rough milling surfaces - fine milling surfaces - cutting journal allowances - rough milling journals - boring and milling journals - removing process tables - fine milling blade shoulders - corrosion inspection - CNC abrasive belt polishing - polishing and repairing arcs and sharp edges - fluorescent inspection - marking - tapping - cleaning - final inspection - warehousing.

[0049] The implementation results show that the process design method of the hollow adjustable blade curved surface diffusion welding joint of the present invention has been used to complete the manufacture of multiple sets and quantities of hollow adjustable blade products. It has passed component assessment, stress testing and whole machine assessment, met the requirements of various design assessment indicators, the dynamic strength reserve coefficient is higher than the design value, and the manufacturing conformity, quality stability and organizational performance reliability are significantly improved.

Claims

1. A process design method for a hollow adjustable blade surface diffusion welding joint, characterized in that: Based on the inner and outer surface features of the hollow adjustable blade, by supplementing the entity, extending the surface, offsetting the parting surface and trimming the large curvature surface, the specific data include the height range of the solid phase diffusion welding joint before welding, the extension surface range, the position of the trimmed large curvature surface, the offset size and tolerance of the parting surface and the requirements for CNC machining; The process design method of the hollow adjustable blade curved surface diffusion welding joint comprises the following steps: Step 1: Parting surface structure analysis The solid phase diffusion welding parting surface of the hollow adjustable blade before welding takes the shaft neck parting surface as the reference plane, extends along the split parting surface to the blade body to the outermost hollow area, and then extends at least 30mm in the direction parallel to the reference plane, and at least 15mm is added in the width direction of the other side; in the length direction of the solid phase diffusion welding parting surface, the shaft neck length is included, and at least 15mm is added for each; in the height direction of the solid phase diffusion welding parting surface, the ratio of the total compression to the total height is not more than 1.5%, and the total compression takes into account the maximum curvature of the parting surface and the quality assurance of the solid phase diffusion welding, and the total compression is preset to be 0.5mm; Step 2: Curved Diffusion Welded Joint Structure In the structure of the curved diffusion welding joint, length × width × height = 420mm × 125mm × 38.50mm, a solid phase diffusion welding compression amount of 0.25mm is reserved for each piece along the profile surface, the profile contour is not greater than 0.05, the surface roughness is not greater than 1.6μm, Φ12mm fine holes are reserved at both ends along the length direction for solid phase diffusion welding assembly positioning, Φ12mm positioning holes are reserved in the middle of the length direction for auxiliary assembly positioning, Φ6mm fine holes are reserved at both ends along the length direction for post-weld CNC machining positioning, and inspection steps are reserved along the circumference for machining parting surface inspection and processing of adjustable blade surface fine-tuning.

2. The process design method for hollow adjustable blade curved surface diffusion welding joint according to claim 1 is characterized in that: The sweep angle of the hollow adjustable blade gradually increases along the split parting surface. The maximum downward sweep angle relative to the journal parting surface is 29.4 degrees, and the maximum upward sweep angle is 11.5 degrees. The maximum height of the adjustable blade is 20.0 mm from the tip of the maximum downward sweep angle of the parting surface to the upper surface of the journal, and the hollow area is 15 mm away from the edge of the adjustable blade.

3. The process design method for hollow adjustable blade curved surface diffusion welding joint according to claim 1 or 2, characterized in that: The superimposed structure of the adjustable blade split parting surface and the solid phase diffusion welding interface is as follows: the upper sweep angle of the part protrudes from the pre-welding workpiece entity, and the lower sweep angle of the part enters the pre-welding workpiece entity. An asymmetric structure is adopted in the process design of the diffusion welding joint to transfer the position with large curvature at the sweep angle to the matching half entity.

4. The process design method for hollow adjustable blade curved surface diffusion welding joint according to claim 3 is characterized in that: After assembly and diffusion welding, a hollow adjustable blade is formed as a whole, wherein: Two upper profile assembly positioning holes are arranged in the middle of both sides in the longer direction of the upper profile, and one upper profile passing positioning hole is arranged on one side in the shorter direction of the upper profile; in addition, two upper profile post-welding processing reference holes are arranged on both side edges in the longer direction of the upper profile; two lower profile assembly positioning holes are arranged in the middle of both sides in the longer direction of the lower profile, and one lower profile passing positioning hole is arranged on one side in the shorter direction of the lower profile, which is conducive to ensuring accurate assembly; in addition, two lower profile post-welding processing reference holes are arranged on both side edges in the longer direction of the lower profile.

5. The process design method for hollow adjustable blade curved surface diffusion welding joint according to claim 1 or 4, characterized in that: After pickling, cleaning and ultrasonic cleaning before welding, the upper and lower halves of the hollow adjustable blades are assembled and fixed with locating pins, and a fixed limit block is used to preset a compression amount of 0.5 mm and enter the furnace for diffusion welding.

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