Electron beam welding method and tooling suitable for long axis blind hole type parts

Abstract

The application discloses an electron beam welding method and tooling suitable for long-axis blind hole parts, and belongs to the field of welding. The method first realizes clamping of two parts by three screw rods uniformly distributed in a circumferential direction of a bottom disc, the bottom disc and a cover plate to ensure concentric alignment. The welding seam is welded twice in a segmented manner, and the formal welding position in the second welding process can cover the screw rod point position, the beam current incremental position and the beam current attenuation position in the first welding process. The method can uniformly distribute the starting and collecting arc positions, and the axial and radial runout of the parts after welding is less than 0.05 mm, so that the concentricity and runout requirements of the parts can be better ensured, the deformation of the parts after welding is small, and thus the final shape, position and size of the parts and the welding seam quality can meet the requirements. The welding of the blind cavity long-axis structure parts is perfectly realized. The method can also realize the welding clamping and high-quality welding of similar structure blind cavity long-axis / tube parts, and has certain guiding and popularization and application values.

Description

Technical Field

[0001] This invention belongs to the field of welding, specifically relating to an electron beam welding method and tooling suitable for long-axis blind hole parts. Background Technology

[0002] The low-pressure turbine shaft is a critical component of the engine. Its main function is to use the high-temperature gas produced by the combustion of fuel in the engine's combustion chamber to drive the turbine, which in turn compresses the gas and increases the engine's intake pressure. Therefore, the low-pressure turbine shaft is a high-temperature rotating part of the engine, and its welding quality directly affects the engine's quality and safety.

[0003] Low-pressure turbine shafts are generally made of GH4169 material. Some have through-hole structures, while others have blind-hole structures. The cavities within them are often oval-shaped, meaning they are small at both ends and large in the middle. Therefore, due to the nature of the blanks or the structure itself, low-pressure turbine shafts are often manufactured using electron beam welding. For shafts with through-hole structures, electron beam welding with a mandrel structure can effectively achieve the welding process. However, low-pressure turbine shafts with blind-cavity structures cannot be welded using the mandrel clamping method. If the argon arc welding positioning chuck method is used for part assembly, it can easily cause the part to run out of tolerances and deform.

[0004] Therefore, for blind cavity structures like low-pressure turbine shaft parts, due to their large length (maximum length 1325mm) and heavy weight, conventional top-mounted welding can easily cause the parts to sag, making it difficult to ensure concentricity. The length of the worktable of a typical electron beam welding machine cannot achieve top-mounted support welding, and the poor concentricity effect seriously affects the welding quality. Summary of the Invention

[0005] To overcome the above-mentioned technical defects, the present invention provides an electron beam welding method and tooling suitable for long-axis blind hole parts. This method can solve the technical problem that existing welding measures for long-axis blind hole parts result in low welding quality due to poor alignment.

[0006] To achieve the above objectives, the present invention employs the following technical content:

[0007] An electron beam welding method suitable for long-axis blind hole parts includes:

[0008] S1: Align the two parts to be welded concentrically, and use three screws to clamp the two aligned parts between the chassis and the cover plate. The three screws are evenly distributed circumferentially along the chassis, dividing the weld into three equal-length first arc segments.

[0009] S2: Take the point that is offset clockwise by the first preset arc length of the screw as the starting point and the point that is offset counterclockwise by the first preset arc length of the adjacent screw as the ending point, and perform the first electron beam welding on the three first arc segments respectively.

[0010] S3: Rotate the two parts that have completed the first welding by a preset angle, and use three screws to clamp the two parts again, dividing the weld into three equal-length second arc segments;

[0011] S4: Take the point that is offset clockwise by the second preset arc length of the screw as the starting point and the point that is offset counterclockwise by the second preset arc length of the adjacent screw as the ending point, and perform the second electron beam welding on the three second arc segments respectively;

[0012] The formal welding position in the second welding process can cover the screw point position, beam current increase position, and beam current decrease position in the first welding process.

[0013] Furthermore, the linear angle between two adjacent screws is 120°.

[0014] Furthermore, the offset screw angle corresponding to the first preset arc length and / or the second preset arc length is 3-8°.

[0015] Furthermore, the offset screw angle is 5°.

[0016] Furthermore, in S2, the welding arc length of the first first arc segment is the arc length corresponding to 5° to 115°; the welding arc length of the second first arc segment is the arc length corresponding to 125° to 235°; and the welding arc length of the third first arc segment is the arc length corresponding to 245° to 355°.

[0017] Furthermore, in S3, the two parts that have completed the first welding are rotated 60° clockwise or counterclockwise.

[0018] Furthermore, before starting S2, the two clamped parts are fixed on the welding turntable, and the A-axis rotation of the welding turntable is set to zero position using one of the screws as a reference.

[0019] Furthermore, after completing the zero-position setting of the rotating A-axis, the positions of the remaining two screws are checked.

[0020] A tooling fixture, applied to the above welding method, includes: a base plate, a cover plate, and three screws;

[0021] The three screws are vertically inserted between the chassis and the cover plate and are evenly distributed along the circumference of the chassis. In use, the parts to be welded are clamped between the chassis and the cover plate and secured by the screws.

[0022] Furthermore, the screw is fixed between the chassis and the cover plate by a hexagonal nut.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention provides an electron beam welding method suitable for long-axis blind-hole components. The method first clamps two components together using three screws evenly distributed circumferentially along a base, along with the base and a cover plate, to ensure concentric alignment. A two-stage segmented welding process is employed to perform secondary welding on the weld seam. The final welding position in the second welding process covers the screw point position, beam current increase position, and beam current decrease position from the first welding process. This method ensures uniform distribution of the arc initiation and termination positions, resulting in axial and radial runout of less than 0.05 mm after welding. This better guarantees the concentricity and runout requirements of the components, minimizing post-weld deformation and ensuring that the final dimensional and weld quality meet requirements. This method perfectly achieves the welding of long-axis blind-cavity components. It can also be used to achieve high-quality welding of similar long-axis / tube blind-cavity components, possessing significant guiding and application value.

[0025] This invention also provides a tooling for use in the above-mentioned method suitable for long-axis blind hole parts. The tooling includes three screws, a base plate and a cover plate. The traditional welding method is a mandrel center clamping structure. The XY stage size of most electron beam welding machines cannot meet the center clamping requirements for welding long-axis parts. At the same time, the blind cavity structure makes mandrel tooling impossible. By using this welding tooling, it is not affected by the blind hole structure and weight of the part. It solves the problem of clamping for blind cavity long-axis electron beam welding very well. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the welding assembly of components and tooling in an electron beam welding method suitable for long-axis blind hole parts, provided by an embodiment of the present invention.

[0027] Figure 2 A left view of the chassis provided in an embodiment of the present invention;

[0028] Figure 3 The right view of the cover plate provided in an embodiment of the present invention.

[0029] Figure label:

[0030] 1-Chassis; 2-Screw; 3-Part A; 4-Part B; 5-Cover plate; 6-Spring; 7-Hexagonal nut. Detailed Implementation

[0031] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0037] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0038] The present invention will now be described in further detail with reference to the accompanying drawings:

[0039] Example

[0040] As mentioned in the background section, low-pressure turbine shafts with blind cavity structures cannot be welded using mandrel clamping methods. Using argon arc welding positioning jaws for part assembly can easily cause part runout and deformation exceeding tolerances. For blind cavity structures like low-pressure turbine shaft parts, due to their large length (maximum length 1325mm) and heavy weight, conventional center-mounted welding methods easily cause part sagging, making it difficult to ensure concentricity. The table length of a typical electron beam welding machine is insufficient for center-mounted support welding, resulting in poor concentricity and severely impacting weld quality.

[0041] To achieve the above objectives, this embodiment provides an electron beam welding method and tooling suitable for long-axis blind hole parts. It can achieve the welding of blind cavity long-axis parts by clamping the parts twice and welding them twice, ensuring that the shape and position dimensions and weld quality of the parts after welding meet the requirements; and achieve high-quality welding of low-pressure turbine shafts of aero engines.

[0042] This method achieves the assembly and clamping of blind cavity long shaft / tube parts by evenly distributing screws around the part. The visible area of ​​the weld seam is segmented by CNC programming of the electron beam welding process. The part is then rotated at a certain angle and clamped again by this tooling. The visible area of ​​the weld seam is segmented again to complete the welding of the entire circumferential weld seam.

[0043] The specific structure of this embodiment will be described in detail below with reference to the accompanying drawings:

[0044] like Figure 1 As shown, this embodiment provides a tooling, including: a chassis 1 and a cover plate 5; three screws 2 are vertically inserted between the chassis 1 and the cover plate 5. After the parts A3 and B4 to be welded are concentrically aligned, the screws 2 are fastened by tightening the hexagonal nuts 7. The hexagonal nuts 7 are equipped with springs 6, preferably disc springs, which can play a certain buffering role.

[0045] The threaded through hole corresponding to screw 2 is preferably an M10 threaded through hole, which facilitates better assembly.

[0046] This embodiment provides an electron beam welding method suitable for long-axis blind hole parts, preferably implemented using the above-mentioned tooling, and the steps include:

[0047] S1: Align the two parts to be welded concentrically, and use three screws 2 to clamp the two aligned parts between the chassis 1 and the cover plate 5. The three screws 2 are evenly distributed circumferentially along the chassis 1, dividing the weld into three equal-length first arc segments.

[0048] S2: Take the point that is offset clockwise by the first preset arc length of the screw 2 as the starting point and the point that is offset counterclockwise by the first preset arc length of the adjacent screw 2 as the ending point, and perform the first electron beam welding on the three first arc segments respectively.

[0049] S3: Rotate the two parts that have completed the first welding by a preset angle, and use the three screws 2 to clamp the two parts again, dividing the weld into three equal-length second arc segments;

[0050] S4: Take the point that is offset clockwise by the second preset arc length of the screw 2 as the starting point and the point that is offset counterclockwise by the second preset arc length of the adjacent screw 2 as the ending point, and perform the second electron beam welding on the three second arc segments respectively.

[0051] The formal welding position in the second welding process can cover the screw point position, beam current increase position, and beam current decrease position in the first welding process.

[0052] Because a screw clamping method is used, and the electron beam welding process includes arc initiation, arc activation, and arc termination, the arc initiation and termination processes inevitably cannot meet the welding requirements. Therefore, to address the above issues, the welding method described in this embodiment is provided, such as... Figure 2 and Figure 3 As shown, the specific steps include the following:

[0053] Step 1: Machining a chassis 1. The boss on the back of chassis 1 mates with the positioning hole on the turntable to achieve quick clamping and positioning. Three M10 threaded through holes are evenly distributed on a suitable pitch circle concentric with chassis 1. Draw a straight line between one of the threaded through holes and the center of chassis 1. Chassis 1 is clamped with parts A3 and B4 to achieve concentric positioning.

[0054] Step 2: Draw two lines parallel to the axis on the outer circumference of part A3, which mates with chassis 1, with the two lines offset by 60 degrees. If there are no lines on the outer surface of part A3, you can arbitrarily assemble it during the first welding. After completing the welding of the three arc segments, use a small electron beam to draw a line along the axis at a position of 60 degrees or 300 degrees.

[0055] Step 3: Prepare three M10 screws 2 of suitable length, and make a cover plate 5 for axial tensioning of the part. The cover plate 5 is positioned to fit the part B4. The cover plate 5 has through holes that are exactly the same as the positions of the three screws 2 on the base plate 1. When assembling the part B4 vertically, align the scribing line on the circumference of the part parallel to the axis with the scribing line on the welding fixture. Screw the three M10 screws 2 onto the base plate 1. The screws 2 pass through the cover plate 5 and press down on the other end of the part B4. After ensuring that the three screws are parallel to the axis of the part B4, tighten them.

[0056] Step 4: Mount the fixture containing the part group (parts A3 and B4 are integrated) onto the welding turntable. First, move the Y-axis so that the machine tool's Y-axis mechanical zero point coincides with the center of the electron gun. Set the scribed position on the fixture as the zero position of the part's rotation A-axis. The specific method is as follows: Using the observation system of the electron beam welding machine, with Y=0, rotate the A-axis and measure the angle values ​​on both sides of the screw at the zero position scribed on the fixture, provided that the screw does not obstruct the welding beam path. For example, when rotating clockwise, the angle value when the screw just does not obstruct the weld seam is A1. Similarly, when rotating counterclockwise, the angle value when the screw just does not obstruct the weld seam is A2. Then, the center angle value of the screw is (A1+A2) / 2=A0. Rotate the A-axis to the value A0, and then set A0 to 0°.

[0057] Step 5: Then rotate axis A and check that the second and third screws 2 are located at 120° and 240° respectively, and both are at the center position of the screws.

[0058] Step Six: The three screws 2 divide the entire visible area of ​​the circumferential weld into three segments. Welding programming is used to implement beam current increment, formal welding, and beam current attenuation in each visible segment. The welding of all three segments is completed in one operation using the selected welding parameters. The vacuum chamber is then vented, and the three screws are loosened, causing the part assembly to rotate 60°. The 60° line on the part assembly is aligned with the marking line on the tooling. The screw positions are then adjusted and tightened. The same method as in Step Five is used to complete a second welding operation on the visible weld area, with the same welding parameters for both operations.

[0059] It is important to note the following: First, during the welding process, a small current is used to check the correctness of the welding procedure, and it is crucial to ensure that the electron beam does not damage the screw during welding. Second, the increasing and decreasing areas formed by the first welding must be completely covered by the area of ​​the second formal welding, ideally with a certain overlap. This ensures that the entire weld has been completely welded by the formal current, preventing incomplete penetration defects.

[0060] In summary, this invention provides an electron beam welding method and tooling suitable for long-axis blind hole parts, which has the following advantages compared to existing welding methods:

[0061] This method first clamps two parts together using three screws evenly distributed circumferentially along the chassis, along with the chassis and cover plate, to ensure concentric alignment. A two-stage, segmented welding process is employed to perform secondary welding on the weld seam. The final welding position in the second stage covers the screw point, current increase, and current decrease positions from the first stage. This method ensures even distribution of the arc start and end points, resulting in axial and radial runout of less than 0.05mm after welding. This better guarantees the concentricity and runout requirements of the parts, minimizing post-weld deformation and ensuring that the final dimensional and weld quality meet requirements. This method perfectly achieves the welding of blind cavity long-shaft structure parts. It can also be used to weld and clamp similar blind cavity long-shaft / tube parts with high-quality welding, demonstrating significant guiding and application value.

[0062] This fixture includes three screws, a base, and a cover plate. Traditional welding methods use a mandrel-center clamping structure. However, the XY stage dimensions of most electron beam welding machines cannot meet the center clamping requirements for welding long-axis parts. At the same time, the blind cavity structure makes mandrel fixtures impossible. This welding fixture is not affected by the blind hole structure and weight of the part, and it effectively solves the problem of clamping long-axis electron beam welding in blind cavities.

[0063] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. An electron beam welding method suitable for long-axis blind hole parts, characterized in that, include: S1: Align the two parts to be welded concentrically, and use three screws (2) to clamp the two aligned parts between the chassis (1) and the cover plate (5). The three screws (2) are evenly distributed circumferentially along the chassis (1) to divide the weld into three equal first arc segments. S2: Take the point of the first preset arc length offset clockwise from the screw (2) as the starting point and the point of the first preset arc length offset counterclockwise from the adjacent screw (2) as the ending point, and perform the first electron beam welding on the three first arc segments respectively; S3: Rotate the two parts that have completed the first welding by a preset angle, and use three screws (2) to clamp the two parts again, dividing the weld into three equal-length second arc segments; S4: Take the point of the second preset arc length offset clockwise from the screw (2) as the starting point and the point of the second preset arc length offset counterclockwise from the adjacent screw (2) as the ending point, and perform the second electron beam welding on the three second arc segments respectively; The formal welding position in the second welding process can cover the screw point position, beam current increase position, and beam current decrease position in the first welding process.

2. The electron beam welding method suitable for long-axis blind hole parts according to claim 1, characterized in that, The line angle between two adjacent screws (2) is 120°.

3. The electron beam welding method suitable for long-axis blind hole parts according to claim 1, characterized in that, The angle of the offset screw (2) corresponding to the first preset arc length and / or the second preset arc length is 3-8°.

4. The electron beam welding method suitable for long-axis blind hole parts according to claim 3, characterized in that, The angle of the offset screw (2) is 5°.

5. The electron beam welding method suitable for long-axis blind hole parts according to claim 4, characterized in that, In S2, the welding arc length of the first first arc segment is the arc length corresponding to 5° to 115°; the welding arc length of the second first arc segment is the arc length corresponding to 125° to 235°; and the welding arc length of the third first arc segment is the arc length corresponding to 245° to 355°.

6. The electron beam welding method suitable for long-axis blind hole parts according to claim 1, characterized in that, In S3, the two parts that have completed the first welding are rotated 60° clockwise or counterclockwise.

7. The electron beam welding method suitable for long-axis blind hole parts according to claim 1, characterized in that, Before starting S2, fix the two clamped parts on the welding turntable, and use one of the screws (2) as a reference to complete the zero position setting of the A-axis rotation of the welding turntable.

8. The electron beam welding method suitable for long-axis blind hole parts according to claim 7, characterized in that, After completing the zero-position setting of the rotating A-axis, check the positions of the other two screws (2).

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