Electron beam welding device compatible with multi-model nozzle extension sections through infrared alignment

Abstract

The utility model discloses an electron beam welding device compatible with multi-model nozzle extension sections through infrared alignment, and belongs to the technical field of precision welding. The device comprises a multi-step base which is made of a polytetrafluoroethylene material and is of a concentric decreasing circular ring step structure, and multi-type self-fixing within the diameter range of 50-400 mm is achieved through natural attachment of steps and a spray pipe extension section; the infrared alignment device is composed of an infrared generator in the center of the base and a detachable focusing piece at the inlet end, and infrared light penetrates through the circle center of the focusing piece to complete real-time coaxial calibration of the upper workpiece and the lower workpiece; the inlet end clamping device is used for synchronously locking and positioning the circle center of the inlet end of the spray pipe through four-way symmetrical fastening screws; the six-degree-of-freedom adjusting mechanism integrates vertical and transverse precision thread assemblies, and micron-order precision adjustment of the butt joint position is achieved. The electron beam welding tool solves the problems that a traditional electron beam welding tool is poor in compatibility, low in butt joint efficiency and insufficient in space adaptability of a vacuum cabin, the coaxiality error is smaller than or equal to 0.05 mm, the welding preparation time is shortened by 70%, and the electron beam welding tool is suitable for efficient and high-precision welding of the extension section of the jet pipe of the airspace engine.

Description

Technical Field

[0001] This utility model belongs to the field of precision welding technology, specifically relating to an electron beam welding device compatible with infrared alignment and multiple nozzle extension sections. Background Technology

[0002] Launch vehicles, as the core means of humankind to access space, directly constrain the advancement of aerospace technology. With the rapid development of my country's aerospace industry, the requirements for the temperature resistance of structural materials, thrust performance, and manufacturing precision of large-size nozzles in rocket engines are becoming increasingly stringent. Among these, the nozzle extension section (tail skirt), a key component of aerospace engine nozzles, has a manufacturing process that directly affects combustion efficiency and structural reliability. Traditional turning methods, limited by the characteristics of high-temperature alloy materials and the processing capabilities of equipment, are unable to meet the forming precision and surface quality requirements of large-size thin-walled components.

[0003] To address the aforementioned challenges, high-power spinning technology, with its advantages of high material utilization and uniform stress distribution, has gradually become an effective solution for forming large-size nozzle extension sections. This technology achieves the extension and strengthening of the metal matrix through plastic deformation, significantly improving the material's mechanical properties while ensuring the uniformity of component thickness and surface finish. However, the spun nozzle extension section requires high-precision butt welding to the nozzle inlet end, and existing electron beam welding processes still face significant bottlenecks: First, traditional tooling fixtures generally use mechanical positioning methods, lacking a real-time dynamic calibration mechanism, making it difficult to control the coaxiality deviation of the conical workpiece butt joint within ±0.1mm; Second, due to the limited operating space of the vacuum chamber, existing clamping devices have high structural redundancy and cannot adapt to the rapid changeover requirements of multiple nozzle assembly models; Third, the pre-alignment process before welding relies on repeated manual adjustments, which is time-consuming and prone to introducing secondary errors.

[0004] Existing technologies, such as the utility model patent CN202222668267.0 "An Electron Beam Welding Fixture for Pressure-Bearing Pipe Assemblies," disclose a welding device based on rotary drive and vertical clamping. While this device can achieve coaxial fixation of cylindrical pressure-bearing pipes, its clamping base uses a rigid chuck structure, which cannot adapt to the conical geometry of the nozzle extension section. Furthermore, this device lacks an integrated active alignment system, relying on the workpiece's own form and position tolerances to ensure docking accuracy, making it difficult to meet the micron-level tolerance requirements of aerospace-grade welding. Its overall structural size is also large, making it unsuitable for the high-efficiency operation requirements within the limited space of a vacuum chamber.

[0005] In summary, developing an electron beam welding device with real-time infrared alignment, multi-model compatibility, and a compact structure has become a key path to overcome the bottleneck of high-precision automated welding technology for large-size nozzle assemblies. This invention, through the innovative design of an infrared generation-feedback calibration system and a modular clamping mechanism, aims to achieve rapid and precise docking of the nozzle extension section and the inlet end, while optimizing the tooling space layout to adapt to vacuum environment operation requirements, thereby systematically improving welding efficiency and finished product qualification rate. Utility Model Content

[0006] This invention addresses the technical problems of existing electron beam welding devices, such as poor compatibility among different models, insufficient nozzle docking accuracy, and low adaptability to the space within a vacuum chamber. It provides an electron beam welding device based on infrared dynamic alignment and multi-step self-positioning. Its core objectives are: to achieve rapid compatibility with various nozzle extension sections within a diameter range of 50-400mm through modular structural design; to ensure the coaxiality error between the nozzle inlet and the extension section is ≤0.05mm by combining infrared optical calibration with six-degree-of-freedom precision adjustment; and to optimize the spatial layout of the device to adapt to the confined working environment of a vacuum welding chamber, thereby improving welding efficiency and process stability.

[0007] To achieve the above objectives, the technical solution of this utility model is as follows:

[0008] An electron beam welding device compatible with multiple nozzle extension sections for infrared alignment includes: (1) a multi-step base: made of PTFE material, with multiple concentric ring-shaped steps of progressively decreasing height on its surface, each step being 3-5mm high, used to horizontally support nozzle extension sections of different diameters, and achieving self-fixation through the natural fit between the steps and the lower part of the nozzle extension section; (2) an infrared alignment device: consisting of an infrared generator installed at the center of the multi-step base, and a circular infrared focusing plate detachably attached to the upper part of the nozzle inlet end, the center of the focusing plate coinciding with the axis of the nozzle inlet end, and the infrared alignment device aligning with the nozzle inlet end. The visible light emitted by the external generator penetrates the center of the focusing plate to achieve coaxial calibration of the upper and lower workpieces; (3) Inlet end clamping device: including a clamping outer ring with four-way symmetrically distributed fastening screws, which realizes the center positioning and rigid fixation of the inlet end of multiple nozzles by synchronously tightening the screws; (4) Six-degree-of-freedom adjustment device: composed of a vertical support rod, a horizontal support rod, a vertical adjustment sleeve, a horizontal adjustment sleeve, a vertical fastening nut, and a horizontal fastening nut, used to adjust the micro displacement of the nozzle inlet end in three-dimensional space (up, down, left, right, front, and back) after clamping, so that the infrared light is accurately aligned with the center of the focusing plate.

[0009] Preferably, in the concentric ring-shaped steps of the multi-step base, the diameter difference between adjacent steps is 3-5mm, the maximum step diameter is 400mm, the minimum step diameter is 50mm, and the height of each step is 4mm, which is used to adapt to nozzle extension sections with diameters ranging from 50mm to 400mm.

[0010] Preferably, the step surface of the multi-step base is covered with an anti-slip coating, and the inclination angle of the sidewall of each step matches the taper of the nozzle extension section to achieve horizontal self-positioning of the nozzle extension section.

[0011] Preferably, the circular infrared focusing plate is made of customizable paper or film material, and its center is generated by electronic drawing software and is the same circle as the inner diameter of the end face of the nozzle inlet. After printing, it is cut into a circular piece with the same diameter as the inlet end.

[0012] Preferably, the circular infrared focusing plate is attached to the upper end face of the nozzle inlet end with peelable adhesive, and the error in the coincidence between the center of the focusing plate and the axis of the inlet end after attachment is ≤0.05mm.

[0013] Preferably, the vertical support rod and the horizontal support rod of the adjustment device are made of 304 stainless steel, and the thread accuracy grade of the vertical fastening nut and the horizontal fastening nut is IT6, so as to achieve micron-level adjustment sensitivity.

[0014] Preferably, the four fastening screws of the inlet end clamping device are symmetrically distributed at 90° intervals on the clamping outer ring, and each screw has an elastic washer at the force-applying end to prevent clamping deformation of the nozzle inlet end.

[0015] Preferably, before the nozzle extension is placed on the multi-step base, the levelness of the base needs to be calibrated with a level, and the coaxiality error between the installation position of the infrared generator and the base axis is ≤0.1mm.

[0016] Compared with the prior art, the present invention has the following significant advantages:

[0017] 1. Multi-model compatibility: The multi-step base, with its dimensional gradient design, covers a diameter range of 50-400mm, making it compatible with various nozzle models and reducing changeover time by 80%.

[0018] 2. High-precision docking: Infrared optical calibration and six-degree-of-freedom fine-tuning work together to improve the coaxiality error from ±0.1mm of traditional tooling to ±0.05mm, significantly improving the welding qualification rate;

[0019] 3. Space adaptability: The modular structure reduces the size of the device by 40%, allowing welding operations to be completed in a vacuum chamber with a height of ≤1.2m;

[0020] 4. Ease of operation: The self-fixing base and four-way synchronous clamping design reduce manual intervention steps by 50%, and the welding preparation time for a single product is reduced from 20 minutes to 5 minutes.

[0021] This invention is particularly suitable for electron beam welding of the extension section and inlet end of the niobium-tungsten alloy nozzle of aerospace engines, and can also be extended to high-precision thin-walled component welding scenarios in the aerospace and energy fields, with broad technical applicability and industrialization value. Attached Figure Description

[0022] Figure 1 The schematic diagram of the overall structure of the device of this utility model shows the spatial layout of the infrared light path, the adjustment device and the multi-step base;

[0023] Figure 2 : Front view of this utility model;

[0024] Figure 3 Top view of this utility model;

[0025] Figure 4 : A perspective view of this utility model;

[0026] Figure 5 : Schematic diagram of the inlet clamping device and the six-degree-of-freedom adjustment device of this utility model. Detailed Implementation

[0027] Example:

[0028] Combined with appendix Figure 1-5 The implementation process of this utility model is described in detail below:

[0029] 1. Component fabrication and pretreatment

[0030] 1.1 Machining of multi-step base:

[0031] The multi-step base 3 is machined using polytetrafluoroethylene (PTFE). The total number of steps is 50, with each step being 4mm high and the diameter decreasing from 400mm to 50mm (the diameter difference between adjacent steps is 7mm). The sidewalls of the steps are machined at a 15° inclination angle to match the taper of the nozzle extension section 1, and the surface is coated with a 0.2mm thick polyurethane anti-slip coating.

[0032] 1.2 Fabrication of Infrared Focusing Film:

[0033] Using CAXA software, draw the projection diagram of the two end faces of the nozzle inlet end of Φ220mm, mark the center, and generate a focusing plate template with crosshairs. Print the template on 80g / m² A4 paper, cut it out, and then evenly paste it onto the upper surface of the inlet end using PVA glue. The center position error should be ≤0.03mm (verified by a laser displacement sensor).

[0034] 2. Device Assembly and Calibration

[0035] 2.1 Fixing the nozzle extension section:

[0036] The nozzle extension section 1 is placed horizontally on the 26th step of the multi-step base 3, corresponding to a diameter of 220mm, and self-positioned using a 15° inclination angle on the side wall of the step. The levelness of the base is calibrated using an electronic level to ensure that the tilt angle deviation is ≤0.05°.

[0037] 2.2 Inlet end clamping and adjustment:

[0038] Place the nozzle inlet end 2 inside the clamping outer ring 5, simultaneously tighten the four fastening screws 6, apply a torque of 2.5 N·m and compress the elastic shim by 0.3 mm, so that the error of the coincidence between the axis of the inlet end and the center of the clamping device is ≤0.02 mm.

[0039] 2.3 Infrared focusing system startup:

[0040] The infrared generator 4 at the center of the multi-step base 3 is activated, emitting visible red light with a wavelength of 850nm. The six-degree-of-freedom adjustment device consists of a vertical support rod 10, a vertical adjustment sleeve 11, a horizontal support rod 13, a horizontal adjustment sleeve 14, a vertical fastening nut 12, and a horizontal fastening nut 15. It performs micro-displacement adjustment of the nozzle inlet end 2 in three-dimensional space (up, down, left, right, and forward and backward) after clamping. The thread precision grade of the vertical fastening nut 12 and the horizontal fastening nut 15 is IT6. The position of the inlet end is finely adjusted in steps of 0.01mm / turn, so that the infrared light accurately penetrates the center of the focusing plate 16.

[0041] 3. Welding parameters and operation

[0042] 3.1 Vacuum chamber compatibility:

[0043] The entire device was placed inside a 1.2m × 0.8m vacuum welding chamber, and a vacuum of 5 × 10⁻³ Pa was applied. The overall height of the device was adjusted to 0.9m, with a lateral extension allowance of ≤50mm, to meet the requirements for operation in confined spaces.

[0044] 3.2 Electron beam welding procedure:

[0045] The electron beam current was set to 120mA, the accelerating voltage to 60kV, and the welding speed to 8mm / s. After starting the welding program, the gap between the nozzle inlet end 2 and the extension section 1 was ≤0.05mm, and the coaxiality error was measured to be 0.04mm (monitored online by a laser interferometer).

[0046] 4. Effect Verification

[0047] 4.1 Compatibility Testing:

[0048] Replace the nozzle extension sections with diameters of Φ80mm, Φ150mm, and Φ320mm, and select the corresponding steps on the multi-step base. The self-fixing time is ≤30 seconds, and there is no need to change the tooling.

[0049] 4.2 Accuracy Comparison Data:

[0050] Traditional mechanical alignment fixtures have an average docking time of 18 minutes and a coaxiality error of 0.12 mm; the infrared focus adjustment time of this utility model is 4 minutes and 30 seconds, with an error of 0.03-0.05 mm (test sample size n=50).

[0051] 4.3 Welding quality assessment:

[0052] The welds were inspected by X-ray and the porosity was ≤0.5%, with no defects of non-fusion found; the nozzle assembly underwent a high-temperature gas impact test at 3,200℃ and the structural deformation was <0.1mm, meeting aerospace-grade quality standards.

[0053] 5. Extensions to other embodiments

[0054] 5.1 Thin-film focusing film alternatives:

[0055] The paper focusing film is replaced with a 0.1mm thick PET film, and the center mark is laser-etched. It can be reused ≥50 times with an accuracy of less than 0.05mm.

Claims

1. An electron beam welding device compatible with infrared alignment for multiple nozzle extension sections, characterized in that, include: (1) Multi-step base (3): Made of PTFE material, its surface is provided with multiple concentric ring steps that decrease in size layer by layer, each step is 3-5mm high, used to horizontally support nozzle extension sections (1) of different diameters, and achieves self-fixation through the natural fit between the steps and the lower part of the nozzle extension section. (2) Infrared alignment device: It consists of an infrared generator (4) installed at the center of the multi-step base (3) and a circular infrared focusing plate (16) that can be detachably attached to the upper part of the nozzle inlet end (2). The center of the focusing plate (16) coincides with the axis of the nozzle inlet end (2). Visible light emitted by the infrared generator (4) penetrates the center of the focusing plate to achieve coaxial calibration of the upper and lower workpieces. (3) Inlet end clamping device: including a clamping outer ring (5) with four-way symmetrically distributed fastening screws (6), which realizes the center positioning and rigid fixation of the inlet end (2) of multiple nozzles by simultaneously tightening the screws; (4) Six-degree-of-freedom adjustment device: It consists of a vertical support rod (10), a horizontal support rod (13), a vertical adjustment sleeve (11), a horizontal adjustment sleeve (14), a vertical fastening nut (12), and a horizontal fastening nut (15), which are used to adjust the micro displacement of the nozzle inlet end (2) in three-dimensional space (up, down, left, right, front and back) after clamping, so that the infrared light is accurately aligned with the center of the focusing plate.

2. The electron beam welding apparatus according to claim 1, characterized in that, In the concentric ring-shaped steps of the multi-step base (3), the diameter difference between adjacent steps is 3-5mm, the maximum step diameter is 400mm, the minimum step diameter is 50mm, and the height of each step is 4mm, which is used to adapt to nozzle extension sections with diameters ranging from 50mm to 400mm.

3. The electron beam welding apparatus according to claim 2, characterized in that, The multi-step base (3) has a non-slip coating on its step surface, and the side wall inclination angle of each step matches the taper of the nozzle extension section (1) to achieve horizontal self-positioning of the nozzle extension section.

4. The electron beam welding apparatus according to claim 1, characterized in that, The circular infrared focusing plate (16) is made of customizable paper or film material. Its center is generated by electronic drawing software and is the same circle as the inner diameter of the end face of the nozzle inlet (2). After printing, it is cut into a circular piece with the same diameter as the inlet end.

5. The electron beam welding apparatus according to claim 4, characterized in that, The circular infrared focusing plate (16) is attached to the upper surface of the nozzle inlet end (2) with peelable adhesive, and the error of the coincidence between the center of the focusing plate and the axis of the inlet end after attachment is ≤0.05mm.

6. The electron beam welding apparatus according to claim 1, characterized in that, The vertical support rod (10) and horizontal support rod (13) of the adjustment device are made of 304 stainless steel, and the thread accuracy of the vertical fastening nut (12) and horizontal fastening nut (15) is IT6 grade, so as to achieve micron-level adjustment sensitivity.

7. The electron beam welding apparatus according to claim 1, characterized in that, The four fastening screws (6) of the inlet end clamping device are symmetrically distributed at 90° intervals on the clamping outer ring, and each screw has an elastic washer at the force application end to prevent the clamping deformation of the nozzle inlet end (2).

8. The electron beam welding apparatus according to claim 1, characterized in that, Before the nozzle extension section (1) is placed on the multi-step base (3), the level of the base needs to be calibrated by a level, and the installation position of the infrared generator (4) and the coaxiality error of the base axis should be ≤0.1mm.

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