Device and method for friction stir welding of longitudinal seam of cylinder section

Abstract

The invention belongs to the technical field of friction stir welding, and particularly relates to a device and method for friction stir welding of a longitudinal joint of a cylinder section. The device comprises a base table, a first base and a second base which are sequentially arranged in the same direction, and the base table is connected with the first base through an X-axis transmission assembly; the first base and the second base are connected through a Y-axis transmission assembly. A main shaft frame is installed on the side, back on to the first base, of the second base and connected with a main shaft through a Z-axis transmission assembly. The end part of the main shaft is provided with a main shaft hole and a cutter handle mounted in the main shaft hole; the cutter handle is used for mounting a cutter or a friction stir welding tool; the driving mechanism can drive the X-axis transmission assembly to drive the first base to move in the X-axis direction, drive the Y-axis transmission assembly to drive the second base to move in the Y-axis direction, drive the Z-axis transmission assembly to drive the main shaft to move in the Z-axis direction and drive the main shaft to rotate. The scheme is simple in structure, the cost can be effectively reduced, and the welding effect is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of friction stir welding, and specifically relates to a device and method for friction stir welding of longitudinal seams of barrel sections. Background Art

[0002] In recent years, the development of the global aerospace industry has entered a new stage of great development and great change. The rocket fuel tank is the main component of the rocket body structure. At present, my country's large-diameter carrier rocket tank is welded by the tank bottom, short shell, barrel section and several flanges. The barrel section structure is generally two semi-circular aluminum alloy parts, which are produced by welding. The TIG welding currently used will inevitably bring a certain degree of welding defects (such as pores, slag inclusions, microcracks, etc.) and welding residual stress. At the same time, the internal structure of the weld has coarse grains and precipitation of strengthening phases. The mechanical properties of the TIG weld will be greatly reduced, and the deformation after welding is large, which is not conducive to subsequent assembly.

[0003] The use of friction stir welding can reduce the above problems caused by TIG welding, but the characteristics of friction stir welding, especially the solid-state welding of conventional friction stir welding, determine that the bottom of the weld needs rigid support, and the periphery of the weld needs to be fixed to prevent the parts from moving during welding. At the same time, conventional friction stir welding also has problems such as incomplete penetration and uneven heat input along the thickness direction of the weld. At the same time, with the continuous increase in the diameter of the rocket (10 meters), the conventional friction stir welding method and its welding equipment will become very large, and the one-time investment cost of the equipment is high.

[0004] Based on this, the present invention is proposed. Summary of the invention

[0005] In order to overcome the problems existing in the related art, the present application provides a device and method for friction stir welding of longitudinal seams of barrel sections, which are used to reduce costs and improve welding effects.

[0006] This application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a device for friction stir welding of longitudinal seams of barrel sections, the device comprising: a base, a first base and a second base arranged in sequence along the same direction, wherein:

[0008] The base platform is connected to the first base via an X-axis transmission assembly;

[0009] The first base and the second base are connected via a Y-axis transmission assembly;

[0010] A spindle frame is installed on a side of the second base facing away from the first base, and the spindle frame is connected to the spindle via a Z-axis transmission assembly;

[0011] The end of the spindle is provided with a spindle hole and a tool handle installed in the spindle hole, and the tool handle is used to install a tool or a stir friction welding tool;

[0012] The device also includes a driving mechanism, which is capable of: driving the X-axis transmission assembly to drive the first base to move in the X-axis direction, driving the Y-axis transmission assembly to drive the second base to move in the Y-axis direction, driving the Z-axis transmission assembly to drive the spindle to move in the Z-axis direction, and driving the spindle to rotate to drive the tool or stir friction welding tool in the tool holder to rotate.

[0013] In a specific embodiment, the X-axis transmission assembly includes:

[0014] An X-axis rack, the X-axis rack being arranged on a side of the base platform facing the first base;

[0015] An X-axis gear, the X-axis gear being arranged on a side of the first base facing the base platform;

[0016] The X-axis rack is meshed with the X-axis gear and can move the first base in the X-axis direction under the drive of the driving mechanism.

[0017] In a specific embodiment, the Y-axis transmission assembly includes:

[0018] A Y-axis guide rail, the Y-axis guide rail is arranged on a side of the first base facing away from the base platform;

[0019] A Y-axis slider, wherein the Y-axis slider wheel is arranged on a side of the second base facing the first base;

[0020] The Y-axis slider can slide along the Y-axis guide rail under the drive of the driving mechanism to drive the second base to move in the Y-axis direction.

[0021] In a specific embodiment, the Z-axis transmission assembly includes:

[0022] Z-axis guide rails, the Z-axis guide rails comprising a first Z-axis guide rail disposed on the inner side of the top end of the spindle frame and a second Z-axis guide rail disposed on the inner side of the bottom end of the spindle frame;

[0023] A Z-axis slider, the Z-axis slider comprising a first Z-axis slider disposed at the upper end of the spindle and matching the first Z-axis guide rail, and a second Z-axis slider disposed at the lower end of the spindle and matching the second Z-axis guide rail;

[0024] Driven by the driving mechanism, the first Z-axis slider and the second Z-axis slider can slide along the first Z-axis guide rail and the second Z-axis guide rail respectively to drive the spindle to move in the Z-axis direction.

[0025] In a specific embodiment, the upper end surface of the friction stir welding tool is provided with a convex key, and the lower end surface of the tool handle is provided with a keyway.

[0026] After the friction stir welding tool is installed on the tool handle, the convex key cooperates with the keyway to realize the up and down floating of the friction stir welding tool in the tool handle.

[0027] In a specific embodiment, the base is a segmented and detachable steel structure component;

[0028] The length of each section of the base is a preset length, and the base includes at least one section of the base with the preset length.

[0029] In a specific embodiment, the base includes a vertical section and a horizontal section, the vertical section is connected to the first base via an X-axis transmission assembly, and the horizontal section serves as a load-bearing section capable of supporting the barrel section to be welded.

[0030] In a specific embodiment, the friction stir welding tool is a double-shoulder friction stir welding tool;

[0031] And / or, there are at least two X-axis racks, which are helical racks with a pressure angle of 15-25° and a module of 1-10;

[0032] And / or, the number of the Y-axis slide rails is at least two, and the number of the Y-axis slide blocks is 4 or 6;

[0033] And / or, the first base is a medium carbon steel structural member with a thickness of not less than 30 mm.

[0034] A second aspect of the present application provides a method for friction stir welding of longitudinal seams of barrel sections, the method using the above-mentioned device, the method comprising:

[0035] Determine the barrel section to be welded, select the corresponding milling cutter and double-shoulder friction stir welding tool according to the barrel section to be processed, and set various parameters of the device;

[0036] The spindle is moved to the starting position, a milling cutter is installed, and the barrel section to be welded is milled according to the set parameters. After the milling is completed, the spindle is moved to the starting position;

[0037] The barrel section to be processed after the milling operation is completed is placed on a fixed fixture, and then a semicircular opening with a preset diameter is milled at one end of the barrel section to be welded according to the set parameters. After the milling is completed, the spindle is moved to the starting position;

[0038] The milling cutter is replaced with a double-shoulder friction stir welding tool, and double-shoulder welding is performed on the barrel section to be welded from the semicircular opening according to the set parameters;

[0039] After welding is completed, the spindle is moved to the starting position.

[0040] In a specific embodiment, the fixing tool comprises:

[0041] A cylinder base, the cylinder base having an arc shape matching the lower semicircular portion of the cylinder section to be welded, and used for fixing the lower semicircular portion of the cylinder section to be welded;

[0042] An inner support assembly, wherein the inner support assembly can be contracted or expanded, and is in an umbrella shape in the expanded state; after the lower semicircular portion of the barrel section to be welded is placed into the barrel base, the upper semicircular portion of the barrel section to be welded is aligned and placed on the lower semicircular portion, and the inner support assembly is expanded in the inner cavity of the barrel surrounded by the upper semicircular portion and the lower semicircular portion to support the inner walls of the upper semicircular portion and the lower semicircular portion in an umbrella shape;

[0043] The upper cover plate of the cylinder has an arc shape matching the upper semicircle of the cylinder section to be welded; after the upper semicircular part of the cylinder section to be welded is aligned and placed on the lower semicircular part, the inner cavity of the upper cover plate of the cylinder abuts against the outer wall of the upper semicircular part to press the upper semicircular part.

[0044] The technical solution provided by the present application may include the following beneficial effects: the technical solution provided by the present application has the advantages of simple structure, low cost, and low one-time investment compared to conventional friction stir welding devices. First, the device does not require the huge gantry frame structure of conventional gantry-type friction stir welding equipment. At the same time, its X-direction relies on the base, and does not require the X-direction (generally bidirectional) base, guide rail and other structures of conventional equipment, and the cost can be reduced by about 80%; secondly, the use of floating double-axis shoulder technology does not require rigid support of the back, simplifies the tooling required for welding, reduces the difficulty of design and manufacturing, and reduces the cost of tooling. Moreover, the use of double-axis shoulder friction stir welding in this embodiment can eliminate the problem of incomplete welding of the back, double-sided forming in one welding, optimize the problem of uneven welding heat input on the upper and lower surfaces, and reduce post-welding deformation.

[0045] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The drawings described herein are used to provide a further understanding of the present application and constitute a part 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 an improper limitation on the present application. In the drawings:

[0047] Figure 1 It is a three-dimensional structural schematic diagram of a device for longitudinal seam friction stir welding of cylinder sections in an embodiment of the present application (the first base is located in the working position shown in the figure);

[0048] Figure 2 yes Figure 1 The corresponding enlarged schematic diagram;

[0049] Figure 3 yes Figure 1 An enlarged schematic diagram of the first base moving to another working position (first viewing angle);

[0050] Figure 4 yes Figure 1 An enlarged schematic diagram of the first base in FIG. 1 being moved to another working position (second viewing angle);

[0051] Figure 5 It is a schematic diagram of the planar structure of a device for friction stir welding of longitudinal seams of cylinder sections in an embodiment of the present application. DETAILED DESCRIPTION

[0053] As described in the background technology, conventional friction stir welding has problems such as incomplete penetration and uneven heat input along the thickness direction of the weld. As the diameter of the rocket continues to increase, the conventional friction stir welding method and welding equipment will become very large, and the one-time investment cost of the equipment is high. Based on this, the researchers proposed a device and method for longitudinal friction stir welding of barrel sections to reduce costs and improve welding effects.

[0054] The preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0055] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0056] The technical solution of the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0057] Figure 1It is a three-dimensional structural schematic diagram of a device for longitudinal seam friction stir welding of cylinder sections in an embodiment of the present application (the first base is located in the working position shown in the figure); Figure 2 yes Figure 1 The corresponding enlarged schematic diagram; Figure 3 yes Figure 1 An enlarged schematic diagram of the first base moving to another working position (first viewing angle); Figure 4 yes Figure 1 An enlarged schematic diagram of the first base in FIG. 1 being moved to another working position (second viewing angle); Figure 5 It is a schematic diagram of the planar structure of a device for friction stir welding of longitudinal seams of cylinder sections in an embodiment of the present application.

[0058] See also Figure 1-5 The device for longitudinal seam friction stir welding of barrel sections provided in this embodiment comprises: a base 100, a first base 1 and a second base 2 arranged in sequence along the same direction, wherein: the base 100 is connected to the first base 1 through an X-axis transmission assembly, the first base 1 and the second base 2 are connected through a Y-axis transmission assembly, a spindle frame 3 is installed on the side of the second base 2 facing away from the first base 1, the spindle frame 3 is connected to a spindle 4 through a Z-axis transmission assembly, the end of the spindle 4 is provided with a spindle hole and a tool holder 40 installed in the spindle hole, and the tool holder 40 is used to install a tool or a friction stir welding tool M. Further, the device of this embodiment also includes a driving mechanism (not shown in the figure), which can: drive the X-axis transmission assembly to drive the first base 1 to move in the X-axis direction, drive the Y-axis transmission assembly to drive the second base 2 to move in the Y-axis direction, drive the Z-axis transmission assembly to drive the spindle 4 to move in the Z-axis direction, and drive the spindle 4 to rotate to drive the tool or the friction stir welding tool M in the tool holder 40 to rotate.

[0059] In this embodiment, the X-axis direction can be understood as the horizontal direction, that is, the first base 1 moves in the left and right direction relative to the base 100 (ie Figure 1 The Y-axis direction can be understood as the longitudinal direction, that is, the second base 2 moves in the vertical direction relative to the first base 1 (i.e. Figure 1 The Z-axis direction can be understood as the horizontal direction, that is, the spindle 4 moves in the horizontal direction relative to the spindle frame 3 (ie Figure 1 In other words, the X-axis, Y-axis and Z-axis are the three axes of the spatial coordinate system. Through the movement on the three axes, the main shaft 4 can move in six directions of front and back, left and right, and up and down within the space.

[0060] It should be noted that the driving mechanism in this embodiment can be provided with one driving motor or multiple independent driving motors according to actual conditions to respectively drive the X-axis transmission assembly, the Y-axis transmission assembly, the Z-axis transmission assembly and the main shaft. Those skilled in the art can reasonably design the driving motor according to actual needs, and this embodiment is not limited to this.

[0061] As a specific example, the X-axis transmission assembly may include an X-axis rack 51 and an X-axis gear 52, wherein the X-axis rack 51 is arranged on the side of the base 100 facing the first base 1, and the X-axis gear 52 is arranged on the side of the first base 1 facing the base 100. The X-axis rack 51 can mesh with the X-axis gear 52, so that since the X-axis gear 52 is fixed on the first base 1 and the X-axis rack 51 is fixed on the base, the driving mechanism can drive the X-axis rack 51 to rotate and then drive the X-axis gear 52 to move along the X-axis rack 51, so that the X-axis gear drives the first base 1 to move in the X-axis direction. As an example, two X-axis racks 51 can be provided, that is, two X-axis racks 51 are provided in parallel on the base 100, and correspondingly, two X-axis gears 52 are provided on the first base 1, respectively meshing with the two X-axis racks 51, so that the movement of the first base 1 on the X-axis is more stable. Optionally, the X-axis rack 51 may be a helical rack with a pressure angle of 15-25° and a module of 1-10. In this embodiment, the first base 1 is a medium carbon steel structure with a thickness of not less than 30 mm, and its moving speed in the X-axis is 0-2000 mm / min.

[0062] As a specific example, the Y-axis transmission assembly may include a Y-axis guide rail 61 and a Y-axis slider 62, wherein the Y-axis guide rail 61 is arranged on the side of the first base 1 facing away from the base 100, and the Y-axis slider 62 is arranged on the side of the second base 2 facing the first base 1. The Y-axis slider 62 can slide along the Y-axis guide rail 61 under the drive of the driving mechanism, so that since the Y-axis guide rail 61 is fixed on the first base 1 and the Y-axis slider 62 is fixed on the second base 2, when the Y-axis slider 62 moves along the Y-axis guide rail 61 in the Y-axis direction, it will drive the second base 2 to move in the Y-axis direction. As an example, two Y-axis guide rails 61 can be set, that is, two Y-axis guide rails 61 are set in parallel along the vertical direction on the first base 1, and then each Y-axis guide rail 61 has two or three Y-axis sliders 62 (that is, the number of Y-axis sliders on the second base 2 is 4 or 6), so that the movement of the second base 2 on the Y-axis is more stable. Optionally, the Y-axis guide rail 61 can be a guide rail of specification 35 or above, and each Y-axis slider 62 can withstand a force of 5000KgF.

[0063] As a specific example, the Z-axis transmission assembly may include a Z-axis guide rail 71 and a Z-axis slider 72, wherein the Z-axis guide rail 71 includes a first Z-axis guide rail 711 disposed on the inner side surface of the top end of the spindle frame 3 and a second Z-axis guide rail 712 disposed on the inner side surface of the bottom end of the spindle frame 3, and the Z-axis slider 72 includes a first Z-axis slider 721 disposed on the upper end of the spindle 4 and matching the first Z-axis guide rail 711 and a second Z-axis slider 722 disposed on the lower end of the spindle 4 and matching the second Z-axis guide rail 712. Driven by the driving mechanism, the first Z-axis slider 721 and the second Z-axis slider 722 can slide along the first Z-axis guide rail 711 and the second Z-axis guide rail 712, respectively. In this way, since the Z-axis guide rail 71 is fixed on the spindle frame 3 and the Z-axis slider 72 is fixed on the spindle 3, the Z-axis slider 72 can drive the spindle 3 to move in the Z-axis direction when moving along the Z-axis guide rail 71. As an example, the thickness of the main shaft frame 3 can be 10 mm, and it can generally be a square structure or a rectangular structure. The main shaft frame 3 can be made of Q345 steel through welding and stress relief tempering to eliminate welding deformation stress and ensure the stability of its structure. Optionally, the Z-axis guide rail 71 generally adopts a guide rail specified in No. 35 or above.

[0064] In this embodiment, the main shaft 4 is driven by the driving mechanism to have a rotation speed of 0-12000 rpm and a torque of 40-120 Nm, thereby achieving stepless speed change.

[0065] In a specific embodiment, the tool handle 40 can be installed with a milling cutter, so that before friction welding, the workpiece to be welded can be milled first, and after the milling operation is completed, the milling cutter is removed, and a stir friction welding tool is installed in the tool handle 40, and then the workpiece to be welded is subjected to friction welding. As an example, in this embodiment, the stir friction welding tool is a double-shoulder stir friction welding tool, specifically, the upper end surface of the double-shoulder stir friction welding tool is provided with a convex key, and the lower end surface of the tool handle 40 is provided with a keyway. After the double-shoulder stir friction welding tool is installed in the tool handle 40, the convex key and the keyway cooperate, so that the stir friction welding tool can float up and down in the tool handle 40.

[0066] In a specific embodiment, the base 100 is a segmented detachable steel structure component, the length of each section of the base 100 is a preset length, and the base 100 includes at least one section of the base 100 of the preset length. As an example, the length of each section of the base 100 can be 6 meters, and different total lengths of the bases 100 can be obtained by splicing together different numbers of bases 100. In this way, for barrel sections of different lengths, different lengths of the bases are required during friction welding. For example, if the length of the barrel section is 17 meters, three bases 100 can be assembled together to obtain a base 100 with a total length of 18 meters. The first base 1 can move on a path of 18 meters, which is sufficient to perform friction welding operations on barrel sections of 17 meters in length. That is, by assembling different numbers of bases 100, friction welding of barrel sections of different lengths can be achieved, which greatly improves the flexibility of the device. In this embodiment, the base 100 can withstand a load-bearing capacity of 10 tons.

[0067] In this embodiment, the base 100 may include a vertical section and a horizontal section. Figure 1 In the figure, the vertical section is the part connected to the first base 1 through the X-axis transmission assembly, and the horizontal section serves as a load-bearing section that can support the barrel section to be welded.

[0068] Regarding the description of the barrel section, for example, it can be a hollow cylinder with openings at both ends, which is formed by aligning the upper and lower parts and then welding. In this embodiment, the barrel section is the middle part of the rocket fuel tank. The rocket fuel tank is a major component of the rocket body structure. At present, my country's large-diameter carrier rocket tank is welded by a tank bottom, a short shell, a barrel section and a plurality of flanges. The barrel section structure is generally 2 semicircular aluminum alloy parts, which are produced by welding.

[0069] The friction stir welding device provided in this embodiment can realize milling, conventional friction stir welding, and double-shoulder friction stir welding. The floating double-shoulder friction stir welding in this embodiment can realize the welding of 3-25mm thick aluminum alloy and magnesium alloy. The diameter of the barrel section to be welded can be above 3500mm, generally 5000mm-10000mm. Its length is generally above 10000mm. The thickness is 6-15mm, which is a 2 series aluminum alloy.

[0070] The following is a description of the method for friction stir welding of longitudinal seams of barrel sections provided in this embodiment. The method uses the above-mentioned friction stir welding device.

[0071] The method includes:

[0072] S110, determining the barrel section to be welded, selecting a corresponding milling cutter and a double-shoulder friction stir welding tool according to the barrel section to be processed, and setting various parameters of the device.

[0073] For example, the corresponding milling cutter and floating double-shoulder friction stir welding tool can be selected according to the thickness and material of the barrel section to be welded, and the corresponding feed speed and spindle rotation speed during milling can be selected; the corresponding feed speed and spindle rotation speed during double-shoulder welding can be selected.

[0074] S120, moving the spindle to the starting position, installing the milling cutter, and performing milling operation on the barrel section to be welded according to the set parameters. After the milling is completed, moving the spindle to the starting position.

[0075] In this step, the barrel section to be welded can be placed in the barrel base 81 (described later), fixed during milling, the milling cutter will be installed and adjusted in position, the milling program will be started, and the spindle will drive the milling cutter to rotate at the set rotation speed and feed speed. After the milling is completed, the spindle will move to the starting position, and then the barrel section to be welded will be separated from the barrel base 81, and the aluminum debris attached to the barrel base 81 during milling will be cleaned to keep it clean. The barrel section to be welded will be turned 180°, placed in the barrel base 81, fixed during milling, and the milling program will be started. This will be repeated until the milling operation of the lower semicircular part and the upper semicircular part of the barrel section to be welded is completed, and the spindle is moved to the starting position.

[0076] S130, placing the barrel section to be processed after the milling operation is completed on a fixed tooling, and then milling a semicircular opening of a preset diameter at one end of the barrel section to be welded according to the set parameters. After the milling is completed, the spindle is moved to the starting position.

[0077] In this step, first put the lower semicircular part of the barrel section to be welded after the milling operation is completed into the barrel base 81, and put the upper semicircular part of the barrel section to be welded after the milling operation is completed on the upper semicircular part to ensure that the two edges after milling are aligned. Put the inner support assembly 82 (described later) into the inner cavity of the barrel surrounded by the upper semicircular part and the lower semicircular part, so that each contour pad 821 (described later) is in close contact with the inside of the barrel section to be welded to achieve tension. The barrel upper cover plate 83 (described later) is placed on the upper semicircular part of the barrel section to be welded, so that the inner wall of the barrel upper cover plate 83 and the outer wall of the upper semicircular part are in close contact, and the upper semicircular part and the entire barrel section to be welded are pressed and tightened. Then adjust the position of the milling cutter, start the milling program, and the spindle drives the milling cutter to rotate at the set rotation speed and mill out a semicircular mouth with a preset diameter (for example, it can be 1 / 2 of the shoulder diameter of the double-shoulder stirring welding tool).

[0078] S140, replacing the milling cutter with a double-shoulder friction stir welding tool, and performing double-shoulder welding on the barrel section to be welded from the semicircular opening according to the set parameters.

[0079] In this step, the program is started using the set rotation speed, feed speed, etc., and floating double-shoulder welding is performed from the semicircular opening milled in the previous step.

[0080] S150, welding is completed, and the main shaft is moved to the starting position.

[0081] In this step, the main shaft moves to the starting position, and then the upper cover plate 83 of the cylinder is adjusted away from the cylinder section to be welded, the inner support assembly 82 is restored from the open state to the contracted state, and its various contour pads 821 are separated from the inner surface of the cylinder section to be welded, and the inner support assembly 82 is taken out from the side.

[0082] Furthermore, the longitudinal seams of the barrel section to be welded are two symmetrical longitudinal seams. Therefore, after welding the longitudinal seam on one side, the barrel section to be welded can be lifted out of the barrel base 81 as a whole with a strap, and then rotated 180°, and the longitudinal seam on the other side of the barrel section to be welded can be welded according to the same steps.

[0083] In the above steps, the cylinder section to be welded includes an upper semicircular part and a lower semicircular part. For the fixing tool, please refer to Figure 1 and Figure 5 The fixing fixture of this embodiment includes a cylinder base 81, an inner support assembly 82 and a cylinder upper cover plate 83. The cylinder base 81 has an arc shape that matches the lower semicircular part of the cylinder section to be welded, and is used to fix the lower semicircular part of the cylinder section to be welded. That is, the cylinder base 81 can be placed on the horizontal section of the base 100, the lower semicircular part of the cylinder section to be welded is placed in the cylinder base 81, and the outer surface of the lower semicircular part of the cylinder section to be welded is in contact with the inner surface of the arc shape of the cylinder base 81.

[0084] The inner support assembly 82 can be retracted or opened, and is umbrella-shaped in the opened state. After the lower semicircular part of the barrel section to be welded is placed into the barrel base 81, the upper semicircular part of the barrel section to be welded is aligned and placed on the lower semicircular part. The inner support assembly 82 is opened in the inner cavity of the barrel surrounded by the upper semicircular part and the lower semicircular part to support the inner wall of the upper semicircular part and the lower semicircular part in an umbrella shape, and is used to support the upper semicircular part and the lower semicircular part during welding to prevent them from moving and deforming during the welding process. After the inner support assembly 82 is retracted, it can be taken out from the inner cavity of the barrel surrounded by the upper semicircular part and the lower semicircular part. Optionally, when the inner support assembly 82 is opened, a contoured pad 821 is set at its end, and the contoured pad 821 abuts against the inner wall of the upper semicircular part and the lower semicircular part. As an example, the inner support component 82 is made of high-strength martensitic stainless steel with a tensile strength of more than 1200MPa. Its retractable range is 100-400mm, and it can be mechanically shrunk and expanded by a cylinder. It is generally equipped with 6, 8, or 10 contoured pads, which are copper blocks. The parts in contact with the parts are installed with nylon or polymer blocks to prevent scratches on the inner walls of the parts.

[0085] The upper cover plate 83 of the cylinder body has an arc shape matching the upper semicircle of the cylinder section to be welded. After the upper semicircle part of the cylinder section to be welded is aligned and placed on the lower semicircle part, the inner cavity of the upper cover plate 83 of the cylinder body abuts against the outer wall of the upper semicircle part to press the upper semicircle part. Due to the contour design of the inner cavity of the upper cover plate 83 of the cylinder body and the outer surface of the upper semicircle part of the cylinder section to be welded, close contact and compaction of the upper semicircle part can be achieved, preventing the upper semicircle part from moving during welding and suppressing deformation of the parts after welding.

[0086] In a specific example, a device provided by this embodiment can be respectively arranged on both sides of the barrel section to be welded. Figure 5 Another device for stir friction welding of the longitudinal seam of the barrel section of this embodiment is placed symmetrically on the right side. The two devices can stir friction welding the gaps on both sides of the barrel section to be welded at the same time, thereby improving the working efficiency.

[0087] The method of the present application is further described in detail below, taking the 2 series aluminum alloy to be welded with a length of 20000 mm, a wall thickness of 8 mm, and a diameter of 3350 mm as an example:

[0088] S1: According to the wall thickness of the barrel section to be welded of 8mm and the material, a three-edge milling cutter with a diameter of 10mm is selected. The needle length of the floating double-shoulder friction stir welding tool is 7.7mm, the diameter is 8mm, the upper shoulder diameter is 24mm, the lower shoulder diameter is 24mm, the feed speed during milling is 200mm / min, and the spindle rotation speed during milling is 8000rpm; the feed speed during double-shoulder welding is 450mm / min, and the spindle rotation speed during double-shoulder welding is 400rpm;

[0089] S2: inserting the milling cutter selected in step S1 into the tool holder;

[0090] S3: Place the lower semicircular part of the cylinder section to be welded into the cylinder base with an inner wall diameter of 3350 mm and a length of 20000 mm, and fix it during milling;

[0091] S4: Move the welding device to the starting position, adjust the position of the milling cutter, start the milling program, and the spindle drives the milling cutter to rotate at the set rotation speed;

[0092] S5: The welding device drives the milling cutter to move at the set feed speed to complete the milling operation;

[0093] S6: Loosen the milling fixture to separate the lower semicircular portion of the barrel section to be welded from the barrel base;

[0094] S7: Clean the aluminum chips attached to the base of the cylinder from milling to keep it clean;

[0095] S8: After the lower semicircular part of the cylinder section to be welded is turned 180°, it is placed into the cylinder base for fixing during milling;

[0096] S9: repeating steps S4, S5, S6 and S7 to complete the milling operation of the lower semicircular part of the barrel section to be welded before welding;

[0097] S10: Repeat the above steps to complete the milling operation of the upper semicircular part of the barrel section to be welded before welding;

[0098] S11: placing the lower semicircular part after the milling operation is completed into the cylinder base;

[0099] S12: placing the upper semicircular part after the milling operation is completed on the lower semicircular part, ensuring that the two edges after milling are aligned;

[0100] S13: placing the inner support assembly into the inner cavity surrounded by the upper semicircular part and the lower semicircular part, so that each contour pad is in close contact with the interior of the cylinder section to be welded, thereby achieving tension;

[0101] S14: placing the upper cover plate of the cylinder onto the upper semicircular portion, so that the inner wall of the upper cover plate of the cylinder and the outer wall of the upper semicircular portion are in close contact, thereby achieving compression and tightening of the upper semicircular portion and the entire cylinder section to be welded;

[0102] S15: Move the welding device to the starting position, adjust the position of the milling cutter, start the milling program, and the spindle drives the milling cutter to rotate at the set rotation speed and mill a semicircular opening with a diameter of 12 mm;

[0103] S16: withdraw the welding device to the starting position and replace it with a floating double-shoulder stirring welding tool for formal welding;

[0104] S17: Start the welding device and the spindle with the set rotation speed of 400 rpm and feed speed of 450 mm / min, and perform floating double-shoulder welding from the semicircular opening with a diameter of 12 mm milled in step S15;

[0105] S18: After welding is completed, the upper cover plate of the cylinder is moved away from the cylinder section to be welded;

[0106] S19: The inner support assembly returns from the tensioned state to the contracted state, and each of its contoured pads is separated from the inner surface of the barrel section to be welded, and the inner support assembly is taken out from the side.

[0107] S20: Use the binding straps to hoist the cylinder section to be welded out of the cylinder base as a whole;

[0108] S21: Rotate the cylinder section to be welded 180° and put it back into the cylinder base, repeat the above steps to complete the welding of the other side.

[0109] S22: After the welding is completed, the upper cover plate of the cylinder is lifted out from above the upper semicircular part of the cylinder section to be welded, and then each contour pad of the inner support assembly is separated from the inner wall of the cylinder section to be welded, and the inner support assembly is taken out from the side;

[0110] S23: hoist the welded cylinder section out of the cylinder base as a whole to complete the welding operation.

[0111] In summary, the device and method provided in this embodiment have the advantages of simple structure, low cost, and low one-time investment compared to conventional friction stir welding devices. First, the device does not require the huge gantry frame structure of conventional gantry-type friction stir welding equipment. At the same time, its X-direction relies on the base, and does not require the X-direction (generally bidirectional) base, guide rail and other structures of conventional equipment, which can reduce the cost by about 80%; secondly, the use of floating double-shoulder technology does not require rigid support on the back, simplifies the tooling required for welding, reduces the difficulty of design and manufacturing, and reduces the cost of tooling. Moreover, the use of double-shoulder friction stir welding in this embodiment can eliminate the problem of incomplete welding on the back, double-sided forming in one welding, optimize the problem of uneven welding heat input on the upper and lower surfaces, and reduce post-welding deformation.

[0112] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A device for friction stir welding of longitudinal seams of barrel sections, characterized in that: The device comprises: a base, a first base and a second base arranged in sequence along the same direction, wherein: The base platform is connected to the first base via an X-axis transmission assembly; The first base and the second base are connected via a Y-axis transmission assembly; A spindle frame is installed on a side of the second base facing away from the first base, and the spindle frame is connected to the spindle via a Z-axis transmission assembly; The end of the spindle is provided with a spindle hole and a tool handle installed in the spindle hole, and the tool handle is used to install a tool or a stir friction welding tool; The device also includes a driving mechanism, which is capable of: driving the X-axis transmission assembly to drive the first base to move in the X-axis direction, driving the Y-axis transmission assembly to drive the second base to move in the Y-axis direction, driving the Z-axis transmission assembly to drive the spindle to move in the Z-axis direction, and driving the spindle to rotate to drive the tool or stir friction welding tool in the tool holder to rotate.

2. The device according to claim 1, characterized in that The X-axis transmission assembly comprises: An X-axis rack, the X-axis rack being arranged on a side of the base platform facing the first base; An X-axis gear, the X-axis gear being arranged on a side of the first base facing the base platform; The X-axis rack is meshed with the X-axis gear and can move the first base in the X-axis direction under the drive of the driving mechanism.

3. The device according to claim 1, characterized in that The Y-axis transmission assembly comprises: A Y-axis guide rail, the Y-axis guide rail is arranged on a side of the first base facing away from the base platform; A Y-axis slider, wherein the Y-axis slider wheel is arranged on a side of the second base facing the first base; The Y-axis slider can slide along the Y-axis guide rail under the drive of the driving mechanism to drive the second base to move in the Y-axis direction.

4. The device according to claim 1, characterized in that The Z-axis transmission assembly comprises: Z-axis guide rails, the Z-axis guide rails comprising a first Z-axis guide rail disposed on the inner side of the top end of the spindle frame and a second Z-axis guide rail disposed on the inner side of the bottom end of the spindle frame; A Z-axis slider, the Z-axis slider comprising a first Z-axis slider disposed at the upper end of the spindle and matching the first Z-axis guide rail, and a second Z-axis slider disposed at the lower end of the spindle and matching the second Z-axis guide rail; Driven by the driving mechanism, the first Z-axis slider and the second Z-axis slider can slide along the first Z-axis guide rail and the second Z-axis guide rail respectively to drive the spindle to move in the Z-axis direction.

5. The device according to claim 1, characterized in that The upper end surface of the friction stir welding tool is provided with a convex key, and the lower end surface of the tool handle is provided with a keyway. After the friction stir welding tool is installed on the tool handle, the convex key cooperates with the keyway to realize the up and down floating of the friction stir welding tool in the tool handle.

6. The device according to any one of claims 1 to 5, characterized in that The base is a segmented and detachable steel structure component; The length of each section of the base is a preset length, and the base includes at least one section of the base with the preset length.

7. The device according to any one of claims 1 to 5, characterized in that The base comprises a vertical section and a horizontal section. The vertical section is connected to the first base via an X-axis transmission assembly. The horizontal section serves as a load-bearing section capable of supporting the barrel section to be welded.

8. The device according to any one of claims 1 to 5, characterized in that The friction stir welding tool is a double-shoulder friction stir welding tool; And / or, there are at least two X-axis racks, which are helical racks with a pressure angle of 15-25° and a module of 1-10; And / or, the number of the Y-axis slide rails is at least two, and the number of the Y-axis slide blocks is 4 or 6; And / or, the first base is a medium carbon steel structural member with a thickness of not less than 30 mm.

9. A method for friction stir welding of longitudinal seams of barrel sections, characterized in that: The method uses the device according to any one of claims 1 to 8, and the method comprises: Determine the barrel section to be welded, select the corresponding milling cutter and double-shoulder friction stir welding tool according to the barrel section to be processed, and set various parameters of the device; The spindle is moved to the starting position, a milling cutter is installed, and the barrel section to be welded is milled according to the set parameters. After the milling is completed, the spindle is moved to the starting position; The barrel section to be processed after the milling operation is completed is placed on a fixed fixture, and then a semicircular opening with a preset diameter is milled at one end of the barrel section to be welded according to the set parameters. After the milling is completed, the spindle is moved to the starting position; The milling cutter is replaced with a double-shoulder friction stir welding tool, and double-shoulder welding is performed on the barrel section to be welded from the semicircular opening according to the set parameters; After welding is completed, the spindle is moved to the starting position.

10. The method according to claim 9, characterized in that The fixed tooling comprises: A cylinder base, the cylinder base having an arc shape matching the lower semicircular portion of the cylinder section to be welded, and used for fixing the lower semicircular portion of the cylinder section to be welded; An inner support assembly, wherein the inner support assembly can be contracted or expanded, and is in an umbrella shape in the expanded state; after the lower semicircular portion of the barrel section to be welded is placed into the barrel base, the upper semicircular portion of the barrel section to be welded is aligned and placed on the lower semicircular portion, and the inner support assembly is expanded in the inner cavity of the barrel surrounded by the upper semicircular portion and the lower semicircular portion to support the inner walls of the upper semicircular portion and the lower semicircular portion in an umbrella shape; The upper cover plate of the cylinder has an arc shape matching the upper semicircle of the cylinder section to be welded; after the upper semicircular part of the cylinder section to be welded is aligned and placed on the lower semicircular part, the inner cavity of the upper cover plate of the cylinder abuts against the outer wall of the upper semicircular part to press the upper semicircular part.

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