Stirring tool for effectively solving ultra-large thickness friction stir welding temperature gradient

Abstract

The utility model discloses a stirring tool capable of effectively solving the temperature gradient of super-thick friction stir welding, which relates to the technical field of friction stir welding and comprises a mounting shaft, a stirring shaft arranged at the bottom end of the mounting shaft, a stirring head upper shaft shoulder arranged at the bottom end of the stirring shaft, a stirring needle arranged at the bottom end of the stirring head upper shaft shoulder and of a conical structure. A stirring head first middle shaft shoulder is arranged at the top of the outer side of the stirring needle, a stirring head second middle shaft shoulder is arranged at the bottom of the outer side of the stirring needle, and a stirring head lower shaft shoulder is arranged at the bottom end of the stirring needle. The friction stir welding device is scientific and novel in structure, can effectively solve the problems of large temperature gradient and non-uniform input heat of ultra-large thickness friction stir welding, enables welding seams with uniform density and good performance to be formed between the first welded workpiece and the second welded workpiece, improves welding strength, obtains high-quality welding joints, and prolongs the service life of a stirring tool at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of friction stir welding, and specifically, to a stirring tool that can effectively solve the temperature gradient of friction stir welding with super-large thickness. Background Technique

[0002] As a new type of solid-phase connection method, friction stir welding effectively overcomes defects such as pores and cracks in fusion welded joints of aluminum alloys, and has the advantages of small residual stress and deformation in the joint, environmental protection and no pollution, etc. There is no strict requirement for surface cleaning preparation of the workpiece before welding, and the friction and stirring during the welding process can remove the oxide film on the surface of the welded part. There is no smoke, dust or spatter during the welding process, and the noise is low. Since friction stir welding only relies on the rotation and movement of the welding head to gradually complete the welding of the entire weld seam, it saves more energy than fusion welding and even conventional friction welding.

[0003] Dual-shoulder friction stir welding, as a supplement to conventional friction stir welding technology, uses a stirring tool in which a common stirring pin connects two shoulders. Each shoulder is in contact with the upper and lower surfaces of the test piece respectively. The lower shoulder replaces the rigid support backing plate at the back, reducing the forging pressure during the welding process and saving the cost of manufacturing rigid devices, effectively solving problems such as large upsetting force, incomplete penetration at the back and root defects in conventional friction stir welding.

[0004] For example, Chinese Patent CN216177530U discloses a friction stir welding dual-shoulder stirring head, which includes a first shoulder, a second shoulder and a stirring pin. The first shoulder and the second shoulder are respectively arranged at both ends of the stirring pin. The opposite end faces of the first shoulder and the second shoulder are both convex surface structures, which have the advantages of simple structure and good adaptability, and can continuously apply pressure to the workpiece to ensure the mechanical properties of the weld seam. However, in the specific application process of the above-mentioned friction stir welding dual-shoulder stirring head, there are the following deficiencies: First, it is not easy to realize the welding of thin plates below 2 mm and thick plates above 30 mm by this dual-shoulder friction stir welding. Especially when using this friction stir welding for thick plate welding, the friction between the shoulder and the workpiece surface generates heat and transfers it to the inside of the workpiece, resulting in a large temperature difference from the surface to the bottom of the workpiece. There is a large temperature gradient in the workpiece during welding, which leads to problems such as uneven heat input and short stirring head life when friction stir welding super-large thickness plates, and it is not easy to realize thick plate friction stir welding, restricting the application range of friction stir welding.

[0005] Regarding the problems in the related technology, no effective solution has been proposed yet. Content of the Utility Model

[0006] Regarding the problems in the related technology, the utility model proposes a stirring tool that can effectively solve the temperature gradient of friction stir welding with super-large thickness to overcome the above-mentioned technical problems existing in the existing related technology.

[0007] To this end, the specific technical solution adopted by the present utility model is as follows:

[0008] A stirring tool that effectively solves the temperature gradient of friction stir welding with an ultra-large thickness, comprising a mounting shaft. A stirring shaft is provided at the bottom end of the mounting shaft. A stirring head upper shoulder is provided at the bottom end of the stirring shaft. A stirring pin is provided at the bottom end of the stirring head upper shoulder. A first middle shoulder of the stirring head is provided at the outer top of the stirring pin. A second middle shoulder of the stirring head is provided at the outer bottom of the stirring pin. A lower shoulder of the stirring head is provided at the bottom end of the stirring pin.

[0009] Furthermore, in order to ensure that a relatively consistent heat input is generated when the stirring tool rubs against the surfaces of the first workpiece to be welded and the second workpiece to be welded, the stirring head upper shoulder, the first middle shoulder of the stirring head, the second middle shoulder of the stirring head, the lower shoulder of the stirring head, and the stirring pin are coaxial; the outer diameter of the bottom end of the stirring head upper shoulder is equal to the outer diameter of the lower shoulder of the stirring head. The stirring pin is provided with a conical structure, and the diameter of the stirring pin gradually decreases in the direction away from the stirring head upper shoulder.

[0010] Furthermore, in order to increase the heat generation by friction, enable the plastic metal inside the workpiece to be subjected to a force in the inward direction and gather at the center of the end face of the shoulder, make the internal materials of the workpiece to be welded mixed evenly, and at the same time reduce the stress concentration inside the stirring pin during the welding process, a first upper groove is provided on the inner side of the bottom end of the stirring head upper shoulder, a second upper groove is provided in the middle of the bottom end of the stirring head upper shoulder, and a third upper groove is provided on the outer side of the bottom end of the stirring head upper shoulder; first middle upper grooves are provided on the inner sides of the top and bottom ends of the first middle shoulder of the stirring head, second middle upper grooves are provided in the middle of the top and bottom ends of the first middle shoulder of the stirring head, and third middle upper grooves are provided on the outer sides of the top and bottom ends of the first middle shoulder of the stirring head; first middle lower grooves are provided on the inner sides of the top and bottom ends of the second middle shoulder of the stirring head, second middle lower grooves are provided in the middle of the top and bottom ends of the second middle shoulder of the stirring head, and third middle lower grooves are provided on the outer sides of the top and bottom ends of the second middle shoulder of the stirring head; a first lower groove is provided on the inner side of the top end of the lower shoulder of the stirring head, a second lower groove is provided in the middle of the top end of the lower shoulder of the stirring head, and a third lower groove is provided on the outer side of the top end of the lower shoulder of the stirring head.

[0011] The beneficial effects of the present utility model are as follows:

[0012] 1. The structure of the present utility model is scientific and novel, and can effectively solve the problems of large temperature gradient and uneven heat input in friction stir welding with an ultra-large thickness, enabling a weld seam with uniform density and good performance to be formed between the first workpiece to be welded and the second workpiece to be welded, improving the welding strength, obtaining a high-quality welded joint, and at the same time increasing the service life of the stirring tool.

[0013] 2. By setting the shoulder on the upper shaft of the stirring head, the first middle shaft shoulder of the stirring head, the second middle shaft shoulder of the stirring head and the shoulder on the lower shaft of the stirring head, when performing friction stir welding, the temperatures of the upper and lower surfaces of the workpiece to be welded can be made more consistent. The heat input of the joint is transferred from the upper and lower surfaces of the workpiece to be welded to the center, the heat input is uniform, and the thermal gradient in the thickness direction is small.

[0014] 3. By setting thread features on the lower surface of the shoulder on the upper shaft of the stirring head, the surface of the first middle shaft shoulder of the stirring head, the surface of the second middle shaft shoulder of the stirring head and the upper surface of the shoulder on the lower shaft of the stirring head, the heat generated by friction can be increased, the internal materials of the workpiece to be welded can be mixed evenly, a weld seam with uniform density and good performance can be formed between the workpieces to be welded, the welding strength can be improved, a high-quality welded joint can be obtained, and at the same time, the service life of the stirring tool is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 FIG. is a schematic structural diagram of a stirring tool that effectively solves the temperature gradient of friction stir welding of ultra-large thickness according to an embodiment of the present invention;

[0017] Figure 2 FIG. is a schematic structural diagram of another angle of a stirring tool that effectively solves the temperature gradient of friction stir welding of ultra-large thickness according to an embodiment of the present invention;

[0018] Figure 3 FIG. is a partial structural diagram of a stirring tool that effectively solves the temperature gradient of friction stir welding of ultra-large thickness according to an embodiment of the present invention;

[0019] Figure 4 FIG. is Figure 2 a partial enlarged view of part A in FIG.;

[0020] Figure 5 FIG. is Figure 3 a partial enlarged view of part B in FIG.;

[0021] Figure 6 FIG. is a top view of a thick plate welded by a stirring tool that effectively solves the temperature gradient of friction stir welding of ultra-large thickness according to an embodiment of the present invention.

[0022] In the figure:

[0023] 1. Upper shoulder of the stirring head; 101. First groove on the head; 102. Second groove on the head; 103. Third groove on the head; 2. First middle shoulder of the stirring head; 201. First upper-middle groove; 202. Second upper-middle groove; 203. Third upper-middle groove; 3. Second middle shoulder of the stirring head; 301. First lower-middle groove; 302. Second lower-middle groove; 303. Third lower-middle groove; 4. Lower shoulder of the stirring head; 401. First lower groove on the head; 402. Second lower groove on the head; 403. Third lower groove on the head; 5. Stirring pin; 6. First workpiece to be welded; 7. Second workpiece to be welded; 8. Weld seam; 9. Mounting shaft; 10. Stirring shaft. Detailed implementation manners

[0024] To further illustrate each embodiment, the present utility model provides drawings, which are a part of the disclosure of the present utility model. They are mainly used to illustrate the embodiments and can be combined with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, those of ordinary skill in the art should be able to understand other possible implementation manners and the advantages of the present utility model. The components in the drawings are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0025] According to an embodiment of the present utility model, there is provided a stirring tool that effectively solves the temperature gradient in friction stir welding of ultra-large thickness.

[0026] Now, the present utility model will be further described in combination with the drawings and specific implementation manners. As Figures 1 - 5 shown, the stirring tool that effectively solves the temperature gradient in friction stir welding of ultra-large thickness according to an embodiment of the present utility model includes a mounting shaft 9. A stirring shaft 10 is provided at the bottom end of the mounting shaft 9 (in addition, in specific applications, the mounting shaft 9 is fixedly connected to the stirring shaft 10, and the stirring shaft 10 is fixedly connected to the upper shoulder 1 of the stirring head). A stirring head upper shoulder 1 is provided at the bottom end of the stirring shaft 10. A stirring pin 5 is provided at the bottom end of the stirring head upper shoulder 1. A first middle shoulder 2 of the stirring head is provided at the outer top of the stirring pin 5. A second middle shoulder 3 of the stirring head is provided at the outer bottom of the stirring pin 5. A lower shoulder 4 of the stirring head is provided at the bottom end of the stirring pin 5.

[0027] By virtue of the above technical solution of the present utility model, the structure of the present utility model is scientific and novel. When performing friction stir welding, the temperatures on the upper and lower surfaces of the workpiece to be welded can be made relatively consistent. The heat input of the joint is transmitted from the upper and lower surfaces of the workpiece to be welded to the center, the heat input amount is uniform, and the thermal gradient in the thickness direction is small. It can be applied to a wider range of materials and weld a wider thickness range.

[0028] In one embodiment, for the upper shoulder 1 of the stirring head, the first middle shoulder 2 of the stirring head, the second middle shoulder 3 of the stirring head, the lower shoulder 4 of the stirring head and the stirring pin 5, the upper shoulder 1 of the stirring head, the first middle shoulder 2 of the stirring head, the second middle shoulder 3 of the stirring head, the lower shoulder 4 of the stirring head and the stirring pin 5 are coaxial; the outer diameter of the bottom end of the upper shoulder 1 of the stirring head is equal to the outer diameter of the lower shoulder 4 of the stirring head (in addition, in specific applications, the upper shoulder 1 of the stirring head is arranged as a conical structure), the stirring pin 5 is arranged as a conical structure, and the diameter of the stirring pin 5 gradually decreases in the direction away from the upper shoulder 1 of the stirring head (in addition, in specific applications, the outer surface of the stirring pin 5 is provided with a thread feature).

[0029] In addition, it should be noted that in specific applications, thread features are provided on the lower surface of the upper shoulder 1 of the stirring head, the upper and lower surfaces of the first middle shoulder 2 of the stirring head, the upper and lower surfaces of the second middle shoulder 3 of the stirring head, and the upper surface of the lower shoulder 4 of the stirring head, which can increase frictional heat generation and make the internal materials of the workpiece to be welded mix evenly. This is the prior art and will not be elaborated here.

[0030] The working principle of the upper shoulder 1 of the stirring head, the first middle shoulder 2 of the stirring head, the second middle shoulder 3 of the stirring head, the lower shoulder 4 of the stirring head and the stirring pin 5 is as follows: the lower surface of the upper shoulder 1 of the stirring head contacts and rubs against the upper surfaces of the first workpiece to be welded 6 and the second workpiece to be welded 7 to generate heat, and the first middle shoulder 2 of the stirring head, the second middle shoulder 3 of the stirring head and the stirring pin 5 are inside the first workpiece to be welded 6 and the second workpiece to be welded 7, so that the internal materials of the workpiece are more evenly plasticized and flowed during stirring. The upper surface of the lower shoulder 4 of the stirring head contacts and rubs against the lower surfaces of the first workpiece to be welded 6 and the second workpiece to be welded 7 to generate heat. Thus, the upper shoulder 1 of the stirring head, the first middle shoulder 2 of the stirring head, the second middle shoulder 3 of the stirring head, the lower shoulder 4 of the stirring head and the stirring pin 5 act together to form a weld 8 with good performance and uniform density between the first workpiece to be welded 6 and the second workpiece to be welded 7.

[0031] The stirring pin 5 is conical, and the diameter of the stirring pin 5 gradually decreases from the connection with the shoulder part to the direction away from the shoulder part, and has a thread feature, which reduces the stress concentration and the possibility of fracture of the stirring head 5, enhances the stirring ability of the stirring head 5, and further increases the material fluidity and reduces the temperature difference in the thickness direction of the welded part.

[0032] In one embodiment, for the upper shoulder 1 of the stirring head, the first middle shoulder 2 of the stirring head, the second middle shoulder 3 of the stirring head, and the lower shoulder 4 of the stirring head, a first upper groove 101 is provided on the inner side of the bottom end of the upper shoulder 1 of the stirring head, a second upper groove 102 is provided in the middle of the bottom end of the upper shoulder 1 of the stirring head, and a third upper groove 103 is provided on the outer side of the bottom end of the upper shoulder 1 of the stirring head (in addition, in specific applications, the first upper groove 101, the second upper groove 102, and the third upper groove 103 are concentric circle structures with gradually increasing diameters); first middle grooves 201 are provided on the inner sides of the top and bottom ends of the first middle shoulder 2 of the stirring head, second middle grooves 202 are provided in the middle of the top and bottom ends of the first middle shoulder 2 of the stirring head, and third middle grooves 203 are provided on the outer sides of the top and bottom ends of the first middle shoulder 2 of the stirring head (in addition, in specific applications, the first middle grooves 201, the second middle grooves 202, and the third middle grooves 203 are concentric circle structures with gradually increasing diameters); first lower grooves 301 are provided on the inner sides of the top and bottom ends of the second middle shoulder 3 of the stirring head, second lower grooves 302 are provided in the middle of the top and bottom ends of the second middle shoulder 3 of the stirring head, and third lower grooves 303 are provided on the outer sides of the top and bottom ends of the second middle shoulder 3 of the stirring head (in addition, in specific applications, the first lower grooves 301, the second lower grooves 302, and the third lower grooves 303 are concentric circle structures with gradually increasing diameters); a first lower head groove 401 is provided on the inner side of the top end of the lower shoulder 4 of the stirring head, a second lower head groove 402 is provided in the middle of the top end of the lower shoulder 4 of the stirring head, and a third lower head groove 403 is provided on the outer side of the top end of the lower shoulder 4 of the stirring head (in addition, in specific applications, the first lower head groove 401, the second lower head groove 402, and the third lower head groove 403 are concentric circle structures with gradually increasing diameters), thereby increasing frictional heat generation, causing the plastic metal in the workpiece to be subjected to an inward force and gather at the center of the shoulder end face, making the internal materials of the workpiece to be welded mix evenly, and at the same time reducing the stress concentration inside the stirring pin 5 during the welding process.

[0033] The working principles of the upper shoulder 1 of the stirring head, the first middle shoulder 2 of the stirring head, the second middle shoulder 3 of the stirring head, and the lower shoulder 4 of the stirring head are as follows: First, the upper shoulder 1 of the stirring head and the lower shoulder 4 of the stirring head jointly clamp the first workpiece to be welded 6 and the second workpiece to be welded 8; the upper shoulder 1 of the stirring head and the lower shoulder 4 of the stirring head have equal diameters to ensure relatively consistent heat input when friction occurs with the surfaces of the first workpiece to be welded 6 and the second workpiece to be welded 7; the temperatures of the upper and lower surfaces of the workpiece to be welded are relatively consistent, and the heat input of the joint is transmitted from the upper and lower surfaces of the workpiece to be welded to the center, with uniform heat input and a small thermal gradient in the thickness direction.

[0034] Then, concentric circular groove features are provided on the lower surface of the upper shoulder 1 of the stirring head, the upper and lower surfaces of the first middle shoulder 2 of the stirring head, the upper and lower surfaces of the second middle shoulder 3 of the stirring head, and the upper surface of the lower shoulder 4 of the stirring head, which can increase frictional heat generation, cause the plastic metal inside the workpiece to be subjected to an inward force, so as to gather at the center of the shoulder end face, make the internal materials of the workpiece to be welded mix evenly, and at the same time reduce the stress concentration inside the stirring pin during the welding process.

[0035] In addition, it should also be noted that in specific applications, the materials of the upper shoulder 1 of the stirring head, the first middle shoulder 2 of the stirring head, the second middle shoulder 3 of the stirring head, the lower shoulder 4 of the stirring head and the stirring pin 5 are all made of materials with a hardness much higher than that of the first workpiece to be welded and the second workpiece to be welded, and wear-resistant alloys are selected or coating treatment is carried out to increase the wear resistance of the stirring head; the first workpiece to be welded 6 and the second workpiece to be welded 7 are made of aluminum alloy materials.

[0036] To facilitate the understanding of the above technical solutions of the present invention, the working principle or operation method of the present invention in the actual process will be described in detail below.

[0037] In actual application, as Figure 6 shown, the output shaft of the external motor is fixedly connected to the mounting shaft 9, and drives the upper shoulder 1 of the stirring head, the first middle shoulder 2 of the stirring head, the second middle shoulder 3 of the stirring head, the lower shoulder 4 of the stirring head and the stirring pin 5 to rotate together (the working principles of the upper shoulder 1 of the stirring head, the first middle shoulder 2 of the stirring head, the second middle shoulder 3 of the stirring head, the lower shoulder 4 of the stirring head and the stirring pin 5 are as described above), so that frictional heat is generated between the present stirring tool and the workpiece. The frictional heat causes the material in front of the stirring head 5 to undergo severe plastic deformation. Then, as the stirring tool moves, the highly plastically deformed material gradually deposits behind the stirring tool, thus forming the weld 8 of friction stir welding; the heat input of the joint is transmitted from the upper and lower surfaces of the workpiece to the center, and at the same time, there is also heat input from the center of the workpiece to the upper and lower surfaces of the workpiece. The heat input is uniform, and the thermal gradient in the thickness direction is small. Finally, the macroscopic morphology of the weld joint obtained is double dumbbell-shaped, wide at the upper and lower surfaces and the center, and narrow between the upper and lower surfaces and the center.

[0038] In the present invention, unless otherwise clearly specified and limited, terms such as "installation", "setting", "connection", "fixation", "rotary connection" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. It can be the internal communication of two components or the interaction relationship between two components. Unless otherwise clearly limited, for those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0039] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A stirring tool for effectively solving the temperature gradient of ultra-thickness friction stir welding, comprising a mounting shaft (9), characterized in that: The bottom end of the mounting shaft (9) is provided with a stirring shaft (10), the bottom end of the stirring shaft (10) is provided with a stirring head upper shoulder (1), the bottom end of the stirring head shoulder (1) is provided with a stirring needle (5), the top of the outer side of the stirring needle (5) is provided with a stirring head first center shoulder (2), the bottom of the outer side of the stirring needle (5) is provided with a stirring head second center shoulder (3), and the bottom end of the stirring needle (5) is provided with a stirring head lower shoulder (4).

2. A stirring tool for effectively solving the temperature gradient of ultra-thickness stir friction welding according to claim 1, characterized in that: The upper shoulder (1) of the stirring head, the first middle shoulder (2) of the stirring head, the second middle shoulder (3) of the stirring head, the lower shoulder (4) of the stirring head and the stirring needle (5) are coaxial.

3. A stirring tool for effectively solving the temperature gradient of ultra-thickness stir friction welding according to claim 2, characterized in that: The outer diameter of the bottom end of the upper shoulder (1) of the stirring head is equal to the outer diameter of the lower shoulder (4) of the stirring head, the stirring needle (5) is arranged to be a conical structure, and the diameter of the stirring needle (5) gradually decreases in the direction away from the shoulder (1) of the stirring head.

4. A stirring tool for effectively solving the temperature gradient of ultra-thickness stir friction welding according to claim 1, characterized in that: A first head groove (101) is provided on the inner side of the bottom end of the shaft shoulder (1) on the stirring head, a second head groove (102) is provided on the middle part of the bottom end of the shaft shoulder (1) on the stirring head, and a third head groove (103) is provided on the outer side of the bottom end of the shaft shoulder (1) on the stirring head.

5. The stirring tool for effectively solving the temperature gradient of ultra-thickness friction stir welding according to claim 1 is characterized in that: The inner sides of the top and bottom ends of the first central shoulder (2) of the stirring head are provided with a first middle-upper groove (201), the middle parts of the top and bottom ends of the first central shoulder (2) of the stirring head are provided with a second middle-upper groove (202), and the outer sides of the top and bottom ends of the first central shoulder (2) of the stirring head are provided with a third middle-upper groove (203).

6. The stirring tool for effectively solving the temperature gradient of ultra-thickness friction stir welding according to claim 1, characterized in that: The inner sides of the top and bottom ends of the second central shoulder (3) of the stirring head are provided with a first middle-lower groove (301), the middle parts of the top and bottom ends of the second central shoulder (3) of the stirring head are provided with a second middle-lower groove (302), and the outer sides of the top and bottom ends of the second central shoulder (3) of the stirring head are provided with a third middle-lower groove (303).

7. The stirring tool for effectively solving the temperature gradient of ultra-thickness friction stir welding according to claim 1 is characterized in that: A first lower head groove (401) is provided on the inner side of the top of the lower shaft shoulder (4) of the stirring head, a second lower head groove (402) is provided in the middle of the top of the lower shaft shoulder (4) of the stirring head, and a third lower head groove (403) is provided on the outer side of the top of the lower shaft shoulder (4) of the stirring head.

Images