In-situ extrusion friction shape correction device and strengthening method for friction stir welding seam of thin-wall weak-rigidity structure

Abstract

The invention provides an in-situ extrusion friction shape correction device for a thin-wall weak-rigidity structure friction stir welding seam. The in-situ extrusion friction shape correction device comprises a shape correction switching mechanism and an in-situ shape correction tool. The shape correction switching mechanism and the in-situ shape correction tool are connected end to end; wherein the shape correcting switching mechanism comprises a first connecting section and a second connecting section, the first connecting section is integrally of a conical structure, and the second connecting section is of a cylindrical structure; the first connecting section is used for being matched with a weld joint friction stir welding main shaft. A mounting hole is formed in the middle of the second connecting section and used for mounting an in-situ shape correcting tool. The welding precision and welding quality of products after friction stir welding of the carrier rocket storage tank thin-wall weak-rigidity structure can be improved, the post-welding shape correction efficiency of the products is improved, and the labor intensity of operators is reduced.

Description

Technical Field

[0001] The invention belongs to the field of friction stir welding, and in particular relates to a strengthening method for an in-situ extrusion friction shaping device for a friction stir weld of a thin-wall weak rigidity structure. Background Art

[0002] With the continuous advancement of major national projects such as space station construction and manned lunar landing, national development has put forward higher requirements for deep space exploration, which in turn puts forward higher requirements for the reliability and carrying capacity of launch vehicles. As an important component of the launch vehicle, the weight of the fuel tank directly affects the carrying capacity of the launch vehicle. Therefore, the design has carried out a series of optimization work on the weight reduction of the launch vehicle tank structure. At present, the thickness of the launch vehicle tank structure has been greatly reduced, and the thinnest thickness of the welding area has been reduced to about 3mm.

[0003] The welding process of the launch vehicle tank structure mainly includes fusion welding process and stir friction welding process. For thin-walled weak rigid tank structure, when the traditional fusion welding process is used for welding, the heat input during the welding process is extremely large, and the welding residual stress of the weld material is extremely large after melting and solidification. Due to the extremely thin thickness of the tank and its poor rigidity, it is difficult to resist the welding residual stress by relying on the strength of the parent material itself. Therefore, the tank shows significant deformation characteristics after welding, so it cannot meet the manufacturing precision requirements of the launch vehicle after welding. When the stir friction welding process is used for welding, although the welding process can be fixed by the strong rigidity of the fixture and the heat input is low, the longitudinal heat input distribution of the weld is uneven during the welding process, and there is also a certain degree of deformation after welding, which is difficult to meet the manufacturing precision requirements of the launch vehicle.

[0004] At present, the research on the post-welding correction of thin-walled weak rigid structural parts mainly focuses on the following aspects:

[0005] (1) Heat treatment and correction after pre-assembly, correction during heat treatment and correction after heat treatment. The main mechanisms are similar, that is, to release the residual stress of the weld to a certain extent by heat treatment and correction of the product, so as to achieve the purpose of correction of the product after welding; because the structural components of the launch vehicle tank are huge, they do not meet the conditions of overall heat treatment in the assembled state or assembly after overall heat treatment after welding, so this scheme is not feasible in the welding and manufacturing process of the launch vehicle tank;

[0006] (2) Deep cryogenic correction. The operation process is as follows: after welding, the product is fixed on the correction tool, and the product and the correction tool are placed in a deep cold environment (liquid nitrogen immersion) for a certain period of time, and then transferred to a warming environment for a certain period of time, finally achieving the purpose of correction. This correction scheme has the disadvantages of high cost, high risk factor in the working environment, and long correction cycle; especially for large structural parts of thin-walled weak rigidity components of the launch vehicle tank, the serious deformation after welding makes it difficult to reinstall it on the correction film tire. In addition, due to the specifications of the tank components, it is difficult to achieve complete deep cryogenic treatment of the structural parts.

[0007] (3) Auxiliary heat tapping treatment. This process is mainly used in the production process of fusion welding of large structural parts. The operation process is: after the welding of the structural parts is completed, the structural parts are assembled on the shaping tooling, and then the welding area is heated and tapped for shaping. It is worth noting that this method is mainly used in the shaping process of fusion welding welds, and the tapping device is used to process the excess height of the fusion welding welds during the shaping process. However, there is no welding excess height in the stir friction welds of thin-walled weak rigid structural parts, so this shaping process has a greater application risk. In addition, the shaping process is mainly completed by the operating workers, so the shaping process is extremely labor-intensive and the shaping efficiency is extremely low. Summary of the invention

[0008] In view of this, the present invention aims to propose an in-situ extrusion friction correction device and strengthening method for stir friction welds of thin-walled weak rigidity structures, which can improve the welding accuracy and welding quality of the product after stir friction welding of the thin-walled weak rigidity structure of the launch vehicle tank, improve the efficiency of post-welding correction of the product, and reduce the labor intensity of operators; realize in-situ efficient correction of stir friction welding welds, and effectively improve the weld strength.

[0009] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0010] An in-situ extrusion friction correction device for thin-walled weak rigidity structure friction stir welds, comprising a correction transfer mechanism and an in-situ correction tool; the correction transfer mechanism and the in-situ correction tool are connected end to end;

[0011] The shape adjustment mechanism comprises a first connecting section and a second connecting section, wherein the first connecting section is in a conical structure as a whole, and the second connecting section is in a cylindrical structure;

[0012] The No. 1 connecting section is used to match the main shaft of the friction stir welding of the weld;

[0013] A mounting hole is provided in the middle of the second connecting section, and the mounting hole is used for installing an in-situ shape correction tool.

[0014] Furthermore, the length of the mounting hole of the second connecting section is L1, and the length of the second connecting section is L2;

[0015] The inner diameter of the mounting hole is D1, and the outer diameter is D2;

[0016] Then L1<L2, D2≥1.5×D1.

[0017] Further, the in-situ shape correction tool includes an installation section and an assembly section;

[0018] A limiting step is provided between the installation section and the assembly section;

[0019] The mounting section is used to be mounted to the shape correction adapter mechanism;

[0020] The length of the installation section is L3, the diameter of the installation section is D3, and the diameter of the limiting step is D4; the length of the assembly section is L4, and the diameter of the assembly section is D5;

[0021] The diameter of D5 is greater than the width of the weld;

[0022] L3≤L1, D1<D4≤D2, D3<D1.

[0023] Furthermore, the size difference between D3 and D1 does not exceed 0.05 mm.

[0024] A strengthening method for an in-situ extrusion friction correction device for a thin-walled weak rigid structure friction stir weld.

[0025] After the friction stir welding of the thin-walled weak rigid structure product weld is completed, the welding spindle is moved to a safe area, and the friction stir welding device is replaced with an in-situ shape correction device;

[0026] After installation, move the welding spindle to the top of the weld, and adjust the spindle running trajectory and process parameters of the shaping process by adjusting the welding program;

[0027] While maintaining the welding assembly state of the thin-walled weak rigid structure product unchanged, the shaping procedure is executed to perform in-situ or offset shaping of the weld; after the shaping is completed, the welding tooling of the thin-walled weak rigid product is disassembled and the product is removed from the shelf.

[0028] Furthermore, during the shaping process, the distance between the center of the spindle motion trajectory and the weld is 0 to the weld width, the spindle speed during the shaping process is 0-200rpm, the spindle travel speed is 10-1000mm / min, and the spindle inclination angle is ±5°.

[0029] Compared with the prior art, the in-situ extrusion friction correction device and strengthening method for thin-walled weak rigidity structure friction stir welds described in the present invention have the following advantages:

[0030] (1) The present invention provides an in-situ extrusion friction correction device and strengthening method for thin-walled weak rigid structure friction stir welds, which solves the problem of warping caused by residual stress after friction stir welding of thin-walled weak rigid structure of launch vehicle tank, and improves the welding quality and manufacturing accuracy of launch vehicles. In addition, after the thin-walled weak rigid structure friction stir weld is corrected in situ, its internal microstructure changes and dislocations increase, so that the strength of the welded joint is further improved, thereby further improving the reliability of the thin-walled weak rigid structure friction stir weld.

[0031] (2) The present invention is an in-situ extrusion friction correction device and strengthening method for thin-walled weak rigid structure friction stir welds, and has developed a convenient, efficient and highly reliable in-situ correction and strengthening process. The process is carried out in-situ after the thin-walled weak rigid structure is welded, so the production efficiency can be greatly improved; the process is completed by the operator controlling the welding spindle, so the labor intensity can be greatly reduced; in addition, since the weld strength can be improved after the correction is completed, the reliability of the product can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 It is a schematic diagram of an in-situ extrusion friction correction device for a thin-walled weak rigidity structure friction stir weld according to an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of a shape correction switching structure according to an embodiment of the present invention;

[0035] Figure 3 Schematic diagram of the in-situ shape correction tool described in an embodiment of the present invention.

[0036] Description of reference numerals:

[0037] 1. Shape adjustment transfer mechanism; 11. No. 1 connecting section; 12. No. 2 connecting section; 2. In-situ shape adjustment tool; 21. Installation section; 22. Assembly section; DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0041] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0042] An in-situ extrusion friction correction device for thin-walled weak rigidity structure friction stir welds, comprising a correction transfer mechanism and an in-situ correction tool; the correction transfer mechanism and the in-situ correction tool are connected end to end;

[0043] The shape adjustment mechanism comprises a first connecting section and a second connecting section, wherein the first connecting section is in a conical structure as a whole, and the second connecting section is in a cylindrical structure;

[0044] The No. 1 connecting section is used to match the weld seam friction stir welding spindle; to meet the condition of connecting the shape correction adapter mechanism to the friction stir welding spindle;

[0045] A mounting hole is provided in the middle of the second connecting section, and the mounting hole is used for installing an in-situ shape correction tool.

[0046] Preferably, the length of the mounting hole of the second connecting section is L1, and the length of the second connecting section is L2;

[0047] The inner diameter of the mounting hole is D1, and the outer diameter is D2;

[0048] Then L1<L2, D2≥1.5×D1. The main purpose of this design is to improve the overall rigidity of the shaping adapter mechanism after the in-situ shaping tool is connected.

[0049] Preferably, the in-situ shaping tool comprises an installation section and an assembly section;

[0050] A limiting step is provided between the installation section and the assembly section;

[0051] The mounting section is used to be mounted to the shape correction adapter mechanism;

[0052] The length of the installation section is L3, the diameter of the installation section is D3, and the diameter of the limiting step is D4; the length of the assembly section is L4, and the diameter of the assembly section is D5;

[0053] The diameter of D5 is greater than the width of the weld;

[0054] L3≤L1, D1<D4≤D2, D3<D1.

[0055] Preferably, the size difference between D3 and D1 does not exceed 0.05 mm to ensure the stability of the rotation of the correction tool during the correction process.

[0056] A strengthening method for an in-situ extrusion friction correction device for a thin-walled weak rigid structure friction stir weld.

[0057] After the friction stir welding of the thin-walled weak rigid structure product weld is completed, the welding spindle is moved to a safe area, and the friction stir welding device is replaced with an in-situ shape correction device;

[0058] After installation, move the welding spindle to the top of the weld, and adjust the spindle running trajectory and process parameters of the shaping process by adjusting the welding program;

[0059] While maintaining the welding assembly state of the thin-walled weak rigid structure product unchanged, the shaping procedure is executed to perform in-situ or offset shaping of the weld; after the shaping is completed, the welding tooling of the thin-walled weak rigid product is disassembled and the product is removed from the shelf.

[0060] Preferably, during the shaping process, the distance between the center of the spindle motion trajectory and the weld is 0 to the weld width, the spindle speed during the shaping process is 0-200 rpm, the spindle travel speed is 10-1000 mm / min, and the spindle inclination angle is ±5°.

[0061] The purpose of in-situ shaping and improving the strength of welded joints after friction stir welding of thin-walled weak rigid structures can be achieved by shaping the friction stir welds. During the shaping process, external stress is provided to the area to be shaped by "extrusion", and auxiliary heat source is provided to the shaping area by "friction", so as to increase the elongation of the material and avoid the risk of micro cracks in the weld under the action of external stress. The "extrusion" and "friction" effects are controlled by adjusting the welding parameters, so that the external stress provided by the shaping tool is superimposed on the residual stress in the weld, so that plastic deformation occurs in the local area of ​​the weld, and the purpose of reducing or homogenizing the residual stress in the weld can be achieved; so as to solve the problem of deformation of thin-walled weak rigid structural parts after friction stir welding.

[0062] In addition, during the shaping process, the stir friction weld is squeezed and rubbed by the main shaft to undergo cold plastic deformation, which causes the microstructure of the weld to change, thereby improving the strength of the weld.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An in-situ extrusion friction correction device for thin-walled weak rigidity structure friction stir welds, characterized by: It includes a shape correction transfer mechanism and an in-situ shape correction tool; the shape correction transfer mechanism and the in-situ shape correction tool are connected end to end; The shape adjustment mechanism comprises a first connecting section and a second connecting section, wherein the first connecting section is in a conical structure as a whole, and the second connecting section is in a cylindrical structure; The No. 1 connecting section is used to match the main shaft of the friction stir welding of the weld; A mounting hole is provided in the middle of the second connecting section, and the mounting hole is used for installing an in-situ shape correction tool.

2. The in-situ extrusion friction correction device for thin-walled weak rigidity structure friction stir weld according to claim 1, characterized in that: The length of the mounting hole of the second connecting section is L1, and the length of the second connecting section is L2; The inner diameter of the mounting hole is D1, and the outer diameter is D2; Then L1<L2, D2≥1.5×D1.

3. The in-situ extrusion friction correction device for thin-walled weak rigidity structure friction stir weld according to claim 1, characterized in that: The in-situ shape correction tool comprises an installation section and an assembly section; A limiting step is provided between the installation section and the assembly section; The mounting section is used to be mounted to the shape correction adapter mechanism; The length of the installation section is L3, the diameter of the installation section is D3, and the diameter of the limiting step is D4; the length of the assembly section is L4, and the diameter of the assembly section is D5; The diameter of D5 is greater than the width of the weld; L3≤L1, D1<D4≤D2, D3<D1.

4. The in-situ extrusion friction correction device for thin-walled weak rigidity structure friction stir weld according to claim 3, characterized in that: The size difference between D3 and D1 does not exceed 0.05mm.

5. A strengthening method for an in-situ extrusion friction shaping device for a thin-walled weak rigidity structure friction stir weld according to any one of claims 1 to 4, characterized in that: After the friction stir welding of the thin-walled weak rigid structure product weld is completed, the welding spindle is moved to a safe area, and the friction stir welding device is replaced with an in-situ shape correction device; After installation, move the welding spindle to the top of the weld, and adjust the spindle running trajectory and process parameters of the shaping process by adjusting the welding program; While maintaining the welding assembly state of the thin-walled weak rigid structure product unchanged, the shaping procedure is executed to perform in-situ or offset shaping of the weld; after the shaping is completed, the welding tooling of the thin-walled weak rigid product is disassembled and the product is removed from the shelf.

6. The strengthening method of the in-situ extrusion friction shaping device for the friction stir weld of a thin-walled weak rigid structure according to claim 5 is characterized by: During the shaping process, the distance between the center of the spindle movement trajectory and the weld is 0 to the weld width, the spindle speed during the shaping process is 0-200rpm, the spindle travel speed is 10-1000mm / min, and the spindle inclination angle is ±5°.

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