Friction stir additive repairing and connecting method

Abstract

The invention provides a friction stir additive repairing and connecting method, which belongs to the field of welding additive and comprises the following steps: (1) designing a prefabricated body structure according to geometric characteristics of a to-be-welded part; (2) processing a stirring head matched with the prefabricated body in structure; and (3) welding parameters are set in a stirring friction solid-phase additive mode, and metallurgical bonding of the prefabricated body and the to-be-repaired or to-be-welded structure is achieved.

Description

Technical Field

[0001] The present application belongs to the field of welding additives, and in particular relates to a stir friction additive repair and connection method. Background Art

[0002] Friction stir repair technology uses the friction heat between the high-speed rotating stirring head and the material to be repaired to partially plasticize or soften the material. Under the stirring and extrusion of the stirring head, the plasticized or softened material is filled into the repair area to form a dense repair layer, thereby achieving material repair. The repair quality is high, and rapid repair can be achieved. It is suitable for material repair under various complex working conditions. However, when repairing thin walls, this technology has disadvantages such as local thinning due to the thinness of the material to be repaired itself and softening and flowing during the stirring process.

[0003] There is an urgent need to find a welding technology that can weld the same or different materials or be used to repair local damage, defects and reserved holes, so as to achieve high repair quality and rapid repair, and be suitable for material repair under various complex working conditions.

[0004] The information in this background technology section is only intended to enhance the understanding of the overall background of the application and should not be construed as an admission or any form of suggestion that the information constitutes the prior art already known to a person of ordinary skill in the art. Summary of the invention

[0005] In order to solve the above problems, this application starts from the perspectives of stirring needle design, additive material selection and structural design to achieve good metallurgical bonding, repair or connection between the additive components and the original structure, and improve the sealing of the additive repair.

[0006] A friction stir additive repair and connection method, comprising the following steps:

[0007] (1) Design the prefabricated structure according to the geometric characteristics of the part to be welded;

[0008] (2) Processing a stirring head that matches the preform structure;

[0009] (3) By using the friction stir solid phase additive method, the welding parameters are set to achieve metallurgical bonding between the prefabricated body and the structure to be repaired or welded.

[0010] In some embodiments, the portion to be welded is a through-hole structure.

[0011] In some embodiments, the preform structure includes a self-supporting portion, the lower end of the self-supporting portion is processed with a conical structure containing threads, and the top end of the self-supporting portion is processed with a geometric groove or protrusion for fastening.

[0012] In some embodiments, the stirring head comprises:

[0013] A clamping portion connected to the friction stir welding device;

[0014] A transition portion located at a lower end of the clamping portion;

[0015] and a spinning fastening portion, which is located at the lower end of the transition portion and cooperates with the geometric groove at the top end of the self-supporting portion to combine the prefabricated structure with the structure to be repaired.

[0016] In some embodiments, the prefabricated structure is a bolt structure.

[0017] In some embodiments, a friction stir additive repair and connection method is used to seal a machining hole reserved for an aviation component.

[0018] In some embodiments, a friction stir additive repair and joining method for dissimilar metal welding comprises the following steps:

[0019] (1) First, a prefabricated hole is machined into metal A;

[0020] (2) Metal A and metal B are then assembled;

[0021] (3) Processing the metal C into an additive structure that matches the prefabricated hole, including a tip, a boss, a thread, and other structures that are conducive to solid-state bonding;

[0022] (4) A friction stir device is used to stir and friction spin metal C into the prefabricated hole to achieve welding.

[0023] In some embodiments, a prefabricated structure is used for solid phase additive repair, including welding of the same material and / or dissimilar materials.

[0024] In some embodiments, solid phase additive manufacturing is used for welding, including the connection or compounding of single-layer or multi-layer structures.

[0025] In some embodiments, the joint form between the prefabricated structure and the structure to be repaired includes one or more of lap joint, butt joint, corner joint, and mortise and tenon joint.

[0026] In some embodiments, the tip spinning structure design of the stirring head includes stirring heads with the same function that can be replaced repeatedly and multiple times derived from this structure.

[0027] In some embodiments, when welding dissimilar metal sheets, it includes whether there are prefabricated holes and whether there is an interface structure design.

[0028] In some embodiments, a preform having an additive and welding function using rotational friction may include a preform with or without threads and any geometry.

[0029] In some embodiments, the friction stir solid phase additive method includes uniaxial or multi-axial solid phase additive repair processes, equipment and tooling.

[0030] Compared with the prior art, this application has at least the following advantages:

[0031] Compared with single mechanical bolt connection, the friction stir bolt additive repair technology causes the material to plasticize and flow, resulting in higher bonding strength and better sealing.

[0032] This technology can be applied to the connection and repair of the same or different materials, and the rotation speed is controllable. In addition, unlike cylindrical additives, this technology can flexibly select bolt materials and design bolt shapes, threads and other structures according to the needs of the materials to be repaired or connected. Compared with additive manufacturing, this technology can repair large thickness structures at one time, and is mainly aimed at the field of discontinuous additives. For the repair of thin-walled parts, thermal deformation or bottom-unsupported materials, molten additives cause body deformation or repair defects, affecting the performance or sealing of the structure itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0034] Figure 1 This is a schematic diagram of the structure of the plate to be repaired and the discontinuous additive particles in some embodiments of the present application;

[0035] Figure 2 This is a schematic diagram of the structure of a stirring head in some embodiments of the present application;

[0036] Figure 3 Comparison of the results of additive repair of prefabricated holes in some embodiments of this application:

[0037] (a) Arc material addition; (b) Solid phase bolt material addition;

[0038] Figure 4 Schematic diagram of a dissimilar metal additive repair structure in some embodiments of the present application;

[0039] Among them, 1-self-supporting part, 2-conical structure with thread, 3-geometric groove, 4-clamping part, 5-transition part, 6-spin fastening part. DETAILED DESCRIPTION

[0040] Below, the specific embodiments of the present application are described in detail in conjunction with the accompanying drawings, but they are not intended to limit the present application. In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is described in detail below in conjunction with the accompanying drawings and specific implementation methods. Below, the embodiments of the present disclosure are further described in detail in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present disclosure.

[0041] All terms (including technical terms or scientific terms) used in the present disclosure have the same meanings as those understood by ordinary technicians in the field to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, such as general dictionaries, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0042] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0043] The following is combined with Figure 1-4 The technical solution of this application is described in detail.

[0044] Example 1

[0045] Pre-processed holes for aviation components, such as Figure 1 As shown in (a), it is necessary to seal during assembly. At present, the reserved holes are usually filled by melt additive. Due to the lack of support, the molten pool collapses and is difficult to completely seal, resulting in leakage.

[0046] In addition, the molten droplets fall into the interior of the component, which may affect the superiority of the component's structural design or the flow of internal airflow at the very least, or fall off and cause blockage, leading to accidents in serious cases. Therefore, this process has safety hazards.

[0047] Based on this, this embodiment provides a stir friction additive repair and connection method, comprising the following steps:

[0048] (1) Adopting additive structure design, designing the prefabricated additive structure (such as Figure 1 As shown in (b), it comprises a self-supporting portion 1, a cone structure 2 including a thread is processed at the lower end, and a geometric groove 3 for fastening is processed at the top of the self-supporting portion 1;

[0049] (2) Processing a stirring head that matches the preform structure;

[0050] (3) Through the friction stir solid phase additive method, the rotation speed, pressing speed, and pressing amount are set to achieve a good metallurgical bond between the preform and the structure to be repaired.

[0051] Compared with stir friction repair, this method will not introduce new flow and filling defects in the matrix structure, improves the quality of the repair area and the matrix structure, and ensures the safe operation of the component.

[0052] Example 2

[0053] Since the current stirring heads are mostly used for welding or additives and have no auxiliary filling function, this embodiment provides a solid-phase additive stirring head that matches the prefabricated structure; the stirring head includes a clamping portion 4, a transition portion 5, and a spinning fastening portion 6. The clamping portion 4 can be connected to the stirring power device, and grooves or protrusions can be processed when necessary to have a fastening function; the transition portion, the transition clamping portion and the spinning fastening portion can be loosely designed when necessary, including loose parts, buckles or screw sleeves to fasten the screwdriver head; the spinning fastening portion can be used to fasten the prefabricated body and apply rotation and downward pressure to ensure the combination of the prefabricated body and the structure to be repaired.

[0054] Example 3

[0055] A friction stir additive repair and connection method for dissimilar metal welding of new energy vehicles (such as Figure 4 As shown), comprising the following steps:

[0056] (1) Processing a prefabricated hole in metal A;

[0057] (2) Assembling metal A and metal B;

[0058] (3) Processing the metal C into the necessary additive structure, including tips, bosses, threads, and other structures that are conducive to solid-state bonding;

[0059] (4) Friction stir spinning C into the prefabricated hole is performed using a friction stir equipment to achieve welding.

[0060] Example 4

[0061] A method for repairing and connecting by stir friction additive is used for discontinuous welding and additive; for welding the same or different materials, or for repairing local damage, defects and reserved holes, comprising the following steps:

[0062] (1) Bolt structure design of additive materials;

[0063] (2) Additive mixing head design;

[0064] (3) Friction stir additive repair and welding: Through the friction stir solid phase additive method, the rotation speed, pressing speed, and pressing amount are set to achieve a good metallurgical bond between the preform and the structure to be repaired and welded.

[0065] Among them, (1) the bolt structure includes a self-supporting structure, a threaded cone, and a fastening geometric groove on the top of the supporting structure; (2) the stirring head includes a clamping structure, a transition structure, and a spinning fastening structure.

[0066] like Figure 3As shown in (a) and (b), compared with the additive repair connection method described in this application and the repair method of arc additive, the blocking rate of arc additive is low. Due to the excessive heat input of arc additive, the edge of the original structure of the component collapses, changing the original structure of the component. The diffusion of the molten additive filling area is much larger than the reserved hole position. In addition, due to the lack of support, some molten droplets fall into the structure and may fall off during high-speed bumps, blocking the power system and posing a major safety hazard. However, using the repair technology of this application, the prefabricated hole is completely blocked, and the entire process is plastic deformation filling with a low temperature, which does not cause the edge structure to collapse.

[0067] This method can be applied to the connection and repair of the same or different materials, and the rotation speed is controllable; according to the requirements of the materials to be repaired or connected, the additive prefabricated structure such as bolt material and the design of bolt shape, thread and other structures can be flexibly selected. This method can repair large thickness structures at one time, and can be mainly used in the field of discontinuous additives; for the repair of thin-walled parts, thermal deformation or bottom-unsupported materials, molten additives cause body deformation or repair defects, affecting the performance or sealing of the structure itself.

[0068] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A friction stir additive repair and connection method, characterized in that: The following steps are involved: (1) Design the prefabricated structure according to the geometric characteristics of the part to be welded; (2) Processing a stirring head that matches the preform structure; (3) By using the friction stir solid phase additive method, the welding parameters are set to achieve metallurgical bonding between the prefabricated body and the structure to be repaired or welded.

2. A friction stir additive repair and connection method according to claim 1, characterized in that: The prefabricated structure comprises a self-supporting part, the lower end of which is processed with a conical structure containing threads, and the top end of which is processed with a geometric groove or protrusion for fastening.

3. A friction stir additive repair and connection method according to claim 1, characterized in that: The stirring head comprises: A clamping portion connected to the friction stir welding device; a transition portion located at a lower end of the clamping portion; and a spinning fastening portion, which is located at the lower end of the transition portion and cooperates with the geometric groove at the top end of the self-supporting portion to combine the prefabricated structure with the structure to be repaired.

4. A friction stir additive repair and connection method according to claim 1, characterized in that: The prefabricated structure is a bolt structure.

5. A friction stir additive repair and connection method according to claim 1, characterized in that: The use of prefabricated structures for solid-phase additive repair includes welding of the same material and / or different materials; the use of solid-phase additive welding includes the connection or compounding of single-layer or multi-layer structures.

6. A friction stir additive repair and connection method according to claim 1, characterized in that: The joint forms between the prefabricated structure and the structure to be repaired include one or more of lap joint, butt joint, corner joint, and mortise and tenon joint.

7. A friction stir additive repair and connection method according to claim 1, characterized in that: When welding dissimilar metal plates, it includes whether there are prefabricated holes and whether there is interface structure design.

8. A friction stir additive repair and connection method according to claim 1, characterized in that: A preform with additive and welding functions using rotational friction, including with or without threads; or a hollow feeding filling of a stirring device derived from this, as well as a single-axis or multi-axis filling design of a filling structure.

9. A friction stir additive repair and connection method according to claim 1, characterized in that: A friction stir additive repair and connection method for dissimilar metal welding, comprising the following steps: (1) First, a prefabricated hole is machined into metal A; (2) Metal A and metal B are then assembled; (3) Processing the metal C into an additive structure that matches the prefabricated hole, including a tip, a boss, a thread, and other structures that are conducive to solid-state bonding; (4) A friction stir device is used to stir and friction spin metal C into the prefabricated hole to achieve welding.

10. Application of a friction stir additive repair and connection method according to any one of claims 1 to 8, characterized in that: Used to plug the reserved processing holes of unsupported aviation components.

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