A method for positioning welding of aluminum alloy pipes

Abstract

The present invention discloses a method for tack welding of aluminum alloy pipes, comprising the following steps: preparing two aluminum alloy pipes with an outer diameter of D; butting the weld joints by wire cutting and sandpaper polishing, with the widest gap at the joint being ≤0.2 mm; after butting, the aluminum alloy pipes are straight as a whole, with the plane of the weld gap perpendicular to the length of the pipes; and removing oil stains and impurities from the pipe surfaces by ultrasonic cleaning. The present invention can effectively locate the weld gap of the aluminum alloy pipes, ensuring accurate welding position.

Description

Technical Field

[0001] The present invention relates to the technical field of welding, and more particularly to a positioning welding method for an aluminum alloy pipe. Background Art

[0002] Aluminum and its alloys have the characteristics of strong thermal conductivity and large heat capacity, large linear expansion coefficient, low melting point and low high-temperature strength. Aluminum alloy welding is one of the most difficult welding processes. Specifically, the welds are prone to defects such as cracks, porosity, insufficient penetration, poor forming, slag inclusions and large welding deformation. The presence of aluminum oxide film on the base metal seriously affects the quality of the weld, which may lead to defects such as insufficient weld penetration, poor forming and slag inclusions. The main methods currently used for aluminum welding include inert gas shielded arc welding, high vacuum brazing, and laser welding. Among them, inert gas shielded arc welding has high operator requirements during the welding process, poor process stability and repeatability, strict pre-weld surface treatment of the weldment, and high cost of inert gas use. High vacuum brazing places very strict demands on the flatness, smoothness, and fit of the welded surface of aluminum alloys, making it prone to defects such as leaking welds. High vacuum brazing requires a series of complex and critical steps, including solder selection, solder preparation, solder filling, workpiece assembly, and brazing temperature and time setting. This can easily cause thermal effects on the aluminum alloy substrate or defects such as weld misalignment, leading to failure. Laser welding is a welding technology that has emerged in recent years. It has advantages such as high energy density and high penetration ratio. Laser welding heads can complete the welding of complex parts with the assistance of a robot. However, due to the strong thermal conductivity and large heat capacity of aluminum alloys, large linear expansion coefficient, low melting point, and low high-temperature strength, high-energy-density laser beams can easily cause excessive heat-affected zones, deformation, cracking, and other failures when welding on aluminum alloys. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a positioning welding method for aluminum alloy pipes.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention discloses a positioning welding method for an aluminum alloy pipe, comprising the following steps:

[0006] Step 1: Prepare two aluminum alloy pipes with an outer diameter of D. Use wire cutting and sandpaper polishing to make the welding interface ready for docking. The widest part of the interface gap is ≤0.2mm. After docking, the aluminum alloy pipes are straight as a whole, and the plane where the welding gap is located is perpendicular to the length direction of the pipes.

[0007] Step 2: Use ultrasonic cleaning to remove oil stains and attached impurities on the surface of the pipe;

[0008] Step 3: Place the cleaned aluminum alloy pipe in an oven for drying;

[0009] Step 4: Punch holes in the middle of the high-temperature tape. The punch radius r is 2mm-3mm. The distance between the center of the first hole and the starting point of the high-temperature tape is greater than r and less than 0.25πD-r. The distance between the punch centers is 0.25πD. The reserved length of the high-temperature tape should be enough to wrap around the aluminum alloy pipe for more than 5 times.

[0010] Step 5: Take out the aluminum alloy pipe dried in step 3, align and close the two ends of the welding interface, and make the widest part of the interface gap ≤0.2mm. Fix it with high-temperature tape, align the middle of the width of the high-temperature tape with the welding gap, and wrap it for more than 5 circles, leaving four evenly distributed holes, each hole corresponding to a positioning welding position;

[0011] Step 6: Place the fixed aluminum alloy pipe into the electron beam welder and further fix it with the side-rotating chuck and ejector in the electron beam welder. After clamping, close the welding chamber door and perform positioning welding on the aluminum alloy pipe through the holes reserved on the high-temperature tape. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and the gun moving motor so that the electron beam can bombard the welding gap on the aluminum alloy pipe through the holes on the high-temperature tape. Perform welding operations on the four positioning welding positions in sequence according to the same process parameters.

[0012] Step 7: Take the aluminum alloy pipe with positioning welding out of the welding chamber of the electron beam welder, tear off the high-temperature tape used for fixing, and then use ultrasonic cleaning to remove the residual glue and other impurities on the surface of the pipe; put the cleaned pipe into the oven for drying;

[0013] Step 8: The aluminum alloy pipe cleaned and dried in step 7 is further fixed by the side rotating chuck and ejector in the electron beam welding machine. After clamping, close the welding chamber door. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and the gun moving motor so that the electron beam from the electron beam gun can bombard the welding gap position on the aluminum alloy pipe. Set the formal welding process parameters as follows: gun chamber vacuum ≤ 5×10 -3 Pa, vacuum degree of welding chamber ≤5×10 -3 Pa, filament current is 22A-24A, high voltage is 68kV-80kV, welding beam current is 4mA-6mA per millimeter of pipe wall thickness, side rotation chuck speed linear speed V is 1000mm / min-1500mm / min, welding time is greater than πD / V, and gun distance is 150mm-200mm;

[0014] Step 9: After welding is completed, take the welded aluminum alloy pipe out of the welding chamber of the electron beam welder.

[0015] Furthermore, in step 2, ultrasonic cleaning uses alcohol with a concentration of ≥95% as a cleaning solution, the cleaning temperature is 30°C-50°C, and the cleaning time is ≥30 minutes.

[0016] Furthermore, in step three, the drying temperature is 80°C-100°C, and the drying time is ≥60 minutes.

[0017] Furthermore, in step five, the center of the hole on the high-temperature tape is on the welding gap and the welding gap can be clearly seen through the hole, and the effective field of view radius of each hole is ≥2mm.

[0018] Furthermore, in step 6, the positioning welding process parameters are set as follows: the vacuum degree of the gun chamber is ≤ 5×10 -3 Pa, vacuum degree of welding chamber ≤5×10 -3 Pa, filament current is 22A-24A, high voltage is 68-80kV, welding beam current is 4mA-6mA per millimeter of pipe wall thickness, gun distance is 150mm-200mm, and single beam duration is 1s.

[0019] Furthermore, in step seven, ultrasonic cleaning uses alcohol with a concentration of ≥95% as a cleaning solution, the cleaning temperature is 50°C-70°C, and the cleaning time is ≥30 minutes.

[0020] Furthermore, in step seven, the drying temperature is 80° C.-100° C., and the drying time is ≥60 min.

[0021] The beneficial effects of the present invention are: it can effectively avoid the risk of introducing impurities and forming defects in the conventional welding method during the positioning welding of aluminum alloy. At the same time, the fixing method is flexible and can meet the welding positioning requirements of aluminum alloy pipes of different sizes. No customized tooling is required, the cost is low, and the operation is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of a structure of the winding device in this embodiment;

[0023] Figure 2 for Figure 1 A magnified schematic diagram of point A in the middle;

[0024] Figure 3 Schematic diagram of a portion of the structure of the winding device in this embodiment;

[0025] Figure 4 Schematic diagram of the structure of the punching mechanism in this embodiment;

[0026] Figure 5 for Figure 4 A magnified schematic diagram of point A in the middle;

[0027] Figure 6is a side view of the punching mechanism in this embodiment;

[0028] Figure 7 Schematic diagram of the structure of the drive seat in this embodiment;

[0029] Figure 8 A side view of the drive seat in this embodiment;

[0030] Figure 9 Schematic diagram of the structure of the transmission ball wheel in this embodiment.

[0031] Figure 1: 1. base; 2. rotating base; 3. screw; 4. screw motor; 5. screw slider; 6. driving base; 7. driving block 1; 8. driving shaft 1; 9. wire rod; 10. slider; 11. moving block; 12. rotating shaft 2; 13. driving block 2; 14. driven shaft 1; 15. driving wheel 2; 16. driving wheel 3; 17. driving belt 2; 18. linkage shaft 1; 19. limiting strip 1; 20. driving wheel 1; 21. driving belt 1; 22. rotating shaft 1; 23. driving wheel 1; 24. base; 25. moving base; 26. rotating shaft 3; 27. driving wheel 2; 28. driving wheel 4; 29. driving belt 3; 30 , driving gear; 31, retaining ring; 32, driving shaft 2; 33, driven gear; 34, driven shaft 2; 35, driving bevel gear; 36, rotating seat; 37, half gear; 38, driven bevel gear; 39, limit seat; 40, lifting plate; 41, connecting rod; 42, rack; 43, guide seat; 44, linkage shaft 2; 45, limit bar 2; 46, spring 1; 47, buffer plate; 48, spring 2; 49, handwheel; 50, driving shaft; 51, rotating disk; 52, driving arc plate; 53, connecting frame; 54, driving rod; 55, transmission ball wheel; 56, semicircular groove; 57, driving groove; 58, unwinding frame; 59, tape roll. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Example 1

[0034] A method for positioning welding of an aluminum alloy pipe comprises the following steps:

[0035] Step 1: Preparation of aluminum alloy pipe and welding interface. The outer diameter of the pipe is 50mm, the wall thickness is 3mm, and the lengths of the two pipe sections are 250mm and 250mm respectively. The welding interface can be completed by wire cutting and sandpaper polishing. The widest part of the interface gap is X max The thickness is 0.18mm. After butt-jointing, the aluminum alloy pipe is straight as a whole, and the plane where the welding gap is located is perpendicular to the length direction of the pipe.

[0036] Step 2: Cleaning of aluminum alloy pipes: Remove oil stains and attached impurities on the pipe surface through ultrasonic cleaning. Ultrasonic cleaning uses 95% alcohol as the cleaning solution, the cleaning temperature is 50°C, and the cleaning time is 30 minutes.

[0037] Step 3: Drying of aluminum alloy pipes: Place the cleaned aluminum alloy pipes in an oven for drying at a temperature of 80°C for 60 minutes.

[0038] Step 4: Prepare the high-temperature tape. Prepare a high-temperature tape of appropriate length according to the size of the aluminum alloy pipe. The width of the high-temperature tape is 100mm. Punch holes in the middle of the width of the high-temperature tape. The punching radius r is 2mm. The distance a between the center of the first hole and the starting point of the high-temperature tape is 30mm. The distance b between the centers of subsequent punches from the first hole is 39.25mm. The reserved length Y of the high-temperature tape is 900mm.

[0039] Step 5: Assemble and fix the aluminum alloy pipe. Take out the cleaned and dried aluminum alloy pipe and align the two ends of the welding interface as close as possible. The widest part of the interface gap is X max The width of the tape is 0.18mm. Use the high-temperature tape prepared in step 4 to fix it. Align the middle of the width of the tape with the weld gap. Wrap it around the aluminum alloy pipe five times and then cut off the excess tape to leave four evenly distributed holes. Each hole corresponds to a tack welding position. The center of the hole reserved on the high-temperature tape is on the weld gap and the weld gap can be clearly seen through the hole. The effective field of view radius of each hole is 2mm.

[0040] Step 6: Position welding of aluminum alloy pipes. Place the fixed aluminum alloy pipes into the electron beam welder and further fix them with the side rotating chuck and ejector in the electron beam welder. After clamping, close the welding chamber door and position weld the aluminum alloy pipes through the holes reserved on the high-temperature tape. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and moving the gun motor so that the electron beam can bombard the welding gap on the aluminum alloy pipe through the holes on the high-temperature tape. Set the positioning welding process parameters as follows: the vacuum degree of the gun chamber is 5×10 -3 Pa, the vacuum degree of the welding chamber is 5×10 -3The welding operation was carried out in sequence on four tack welding positions according to the same process parameters: Pa, filament current 24A, high voltage 70kV, welding beam current 15mA, gun distance 150mm, single down-beam beam duration 1s;

[0041] Step 7: Cleaning the aluminum alloy pipe: Remove the welded aluminum alloy pipe from the welding chamber of the electron beam welder and remove the high-temperature tape used to secure it. Then, perform ultrasonic cleaning to remove any residual adhesive and other impurities on the pipe surface. Ultrasonic cleaning uses 95% alcohol as the cleaning solution at a temperature of 70°C for 30 minutes. The cleaned pipe is then placed in an oven for drying at 80°C for 60 minutes.

[0042] Step 8: Formal welding of the welding gap of the aluminum alloy pipe. The aluminum alloy pipe cleaned and dried in step 7 is further fixed by the side rotating chuck and ejector in the electron beam welding machine. After clamping, close the welding chamber door. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and the gun moving motor so that the electron beam from the electron beam gun can bombard the welding gap position on the aluminum alloy pipe. Set the formal welding process parameters as follows: the vacuum degree of the gun chamber is 5×10 -3 Pa, the vacuum degree of the welding chamber is 5×10 -3 Pa, filament current 24A, high voltage 70kV, welding beam current 15mA, side chuck speed linear speed V 1000mm / min, welding time 12s, gun distance 150mm;

[0043] Step 9: After welding is completed, take the welded aluminum alloy pipe out of the welding chamber of the electron beam welder.

[0044] Example 2

[0045] A method for positioning welding of an aluminum alloy pipe comprises the following steps:

[0046] Step 1: Preparation of aluminum alloy pipe and welding interface. The outer diameter of the pipe is 50mm, the wall thickness is 5mm, and the lengths of the two pipe sections are 250mm and 250mm respectively. The welding interface can be completed by wire cutting and sandpaper polishing. The widest part of the interface gap is X max The thickness is 0.18mm. After butt-jointing, the aluminum alloy pipe is straight as a whole, and the plane where the welding gap is located is perpendicular to the length direction of the pipe.

[0047] Step 2: Cleaning of aluminum alloy pipes: Remove oil stains and attached impurities on the pipe surface through ultrasonic cleaning. Ultrasonic cleaning uses 95% alcohol as the cleaning solution, the cleaning temperature is 50°C, and the cleaning time is 30 minutes.

[0048] Step 3: Drying of aluminum alloy pipes: Place the cleaned aluminum alloy pipes in an oven for drying at a temperature of 80°C for 60 minutes.

[0049] Step 4: Prepare the high-temperature tape. Prepare a high-temperature tape of appropriate length according to the size of the aluminum alloy pipe. The width of the high-temperature tape is 100mm. Punch holes in the middle of the width of the high-temperature tape. The punching radius r is 2mm. The distance a between the center of the first hole and the starting point of the high-temperature tape is 30mm. The distance b between the centers of subsequent punches from the first hole is 39.25mm. The reserved length Y of the high-temperature tape is 900mm.

[0050] Step 5: Assemble and fix the aluminum alloy pipe. Take out the cleaned and dried aluminum alloy pipe and align the two ends of the welding interface as close as possible. The widest part of the interface gap is X max The width of the tape is 0.18mm. Use the high-temperature tape prepared in step 4 to fix it. Align the middle of the width of the tape with the weld gap. Wrap it around the aluminum alloy pipe five times and then cut off the excess tape to leave four evenly distributed holes. Each hole corresponds to a tack welding position. The center of the hole reserved on the high-temperature tape is on the weld gap and the weld gap can be clearly seen through the hole. The effective field of view radius of each hole is 2mm.

[0051] Step 6: Position welding of aluminum alloy pipes. Place the fixed aluminum alloy pipes into the electron beam welder and further fix them with the side rotating chuck and ejector in the electron beam welder. After clamping, close the welding chamber door and position weld the aluminum alloy pipes through the holes reserved on the high-temperature tape. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and moving the gun motor so that the electron beam can bombard the welding gap on the aluminum alloy pipe through the holes on the high-temperature tape. Set the positioning welding process parameters as follows: the vacuum degree of the gun chamber is 5×10 -3 Pa, the vacuum degree of the welding chamber is 5×10 -3 The welding operation was carried out in sequence on four tack welding positions according to the same process parameters: Pa, filament current 24A, high voltage 70kV, welding beam current 25mA, gun distance 150mm, single down-beam duration 1s;

[0052] Step 7: Cleaning the aluminum alloy pipe: Remove the welded aluminum alloy pipe from the welding chamber of the electron beam welder and remove the high-temperature tape used to secure it. Then, perform ultrasonic cleaning to remove any residual adhesive and other impurities on the pipe surface. Ultrasonic cleaning uses 95% alcohol as the cleaning solution at a temperature of 70°C for 30 minutes. The cleaned pipe is then placed in an oven for drying at 80°C for 60 minutes.

[0053] Step 8: Formal welding of the welding gap of the aluminum alloy pipe. The aluminum alloy pipe cleaned and dried in step 7 is further fixed by the side rotating chuck and ejector in the electron beam welding machine. After clamping, close the welding chamber door. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and the gun moving motor so that the electron beam from the electron beam gun can bombard the welding gap position on the aluminum alloy pipe. Set the formal welding process parameters as follows: the vacuum degree of the gun chamber is 5×10 -3 Pa, the vacuum degree of the welding chamber is 5×10 -3 Pa, filament current 24A, high voltage 70kV, welding beam current 25mA, side chuck speed linear speed V 1000mm / min, welding time 12s, gun distance 150mm;

[0054] Step 9: After welding is completed, take the welded aluminum alloy pipe out of the welding chamber of the electron beam welder.

[0055] Example 3

[0056] A method for positioning welding of an aluminum alloy pipe comprises the following steps:

[0057] Step 1: Preparation of aluminum alloy pipe and welding interface. The outer diameter of the pipe is 50mm, the wall thickness is 5mm, and the lengths of the two pipe sections are 250mm and 250mm respectively. The welding interface can be completed by wire cutting and sandpaper polishing. The widest part of the interface gap is X max The thickness is 0.18mm. After butt-jointing, the aluminum alloy pipe is straight as a whole, and the plane where the welding gap is located is perpendicular to the length direction of the pipe.

[0058] Step 2: Cleaning of aluminum alloy pipes: Remove oil stains and attached impurities on the pipe surface through ultrasonic cleaning. Ultrasonic cleaning uses 95% alcohol as the cleaning solution, the cleaning temperature is 50°C, and the cleaning time is 30 minutes.

[0059] Step 3: Drying of aluminum alloy pipes: Place the cleaned aluminum alloy pipes in an oven for drying at a temperature of 80°C for 60 minutes.

[0060] Step 4: Prepare the high-temperature tape. Prepare a high-temperature tape of appropriate length according to the size of the aluminum alloy pipe. The width of the high-temperature tape is 100mm. Punch holes in the middle of the width of the high-temperature tape. The punching radius r is 3mm. The distance a between the center of the first hole and the starting point of the high-temperature tape is 30mm. The distance b between the centers of subsequent punches from the first hole is 39.25mm. The reserved length Y of the high-temperature tape is 900mm.

[0061] Step 5: Assemble and fix the aluminum alloy pipe. Take out the cleaned and dried aluminum alloy pipe and align the two ends of the welding interface as close as possible. The widest part of the interface gap is Xmax The width of the tape is 0.18mm. Use the high-temperature tape prepared in step 4 to fix it. Align the middle of the width of the tape with the weld gap. Wrap it around the aluminum alloy pipe five times and then cut off the excess tape to leave four evenly distributed holes. Each hole corresponds to a tack welding position. The center of the hole reserved on the high-temperature tape is on the weld gap and the weld gap can be clearly seen through the hole. The effective field of view radius of each hole is 3mm.

[0062] Step 6: Position welding of aluminum alloy pipes. Place the fixed aluminum alloy pipes into the electron beam welder and further fix them with the side rotating chuck and ejector in the electron beam welder. After clamping, close the welding chamber door and position weld the aluminum alloy pipes through the holes reserved on the high-temperature tape. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and moving the gun motor so that the electron beam can bombard the welding gap on the aluminum alloy pipe through the holes on the high-temperature tape. Set the positioning welding process parameters as follows: the vacuum degree of the gun chamber is 5×10 -3 Pa, the vacuum degree of the welding chamber is 5×10 -3 The welding operation was carried out in sequence on four tack welding positions according to the same process parameters: Pa, filament current 24A, high voltage 75kV, welding beam current 25mA, gun distance 150mm, single beam down duration 1s;

[0063] Step 7: Cleaning the aluminum alloy pipe: Remove the welded aluminum alloy pipe from the welding chamber of the electron beam welder and remove the high-temperature tape used to secure it. Then, perform ultrasonic cleaning to remove any residual adhesive and other impurities on the pipe surface. Ultrasonic cleaning uses 95% alcohol as the cleaning solution at a temperature of 70°C for 30 minutes. The cleaned pipe is then placed in an oven for drying at 80°C for 60 minutes.

[0064] Step 8: Formal welding of the welding gap of the aluminum alloy pipe. The aluminum alloy pipe cleaned and dried in step 7 is further fixed by the side rotating chuck and ejector in the electron beam welding machine. After clamping, close the welding chamber door. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and the gun moving motor so that the electron beam from the electron beam gun can bombard the welding gap position on the aluminum alloy pipe. Set the formal welding process parameters as follows: the vacuum degree of the gun chamber is 5×10 -3 Pa, the vacuum degree of the welding chamber is 5×10 -3 Pa, filament current 24A, high voltage 75kV, welding beam current 25mA, side chuck speed linear speed V 1000mm / min, welding time 12s, gun distance 150mm;

[0065] Step 9: After welding is completed, take the welded aluminum alloy pipe out of the welding chamber of the electron beam welder.

[0066] Example 4

[0067] A method for positioning welding of an aluminum alloy pipe comprises the following steps:

[0068] Step 1: Preparation of aluminum alloy pipe and welding interface. The outer diameter of the pipe is 80mm, the wall thickness is 3mm, and the lengths of the two pipe sections are 250mm and 250mm respectively. The welding interface can be completed by wire cutting and sandpaper polishing. The widest part of the interface gap is X max The thickness is 0.18mm. After butt-jointing, the aluminum alloy pipe is straight as a whole, and the plane where the welding gap is located is perpendicular to the length direction of the pipe.

[0069] Step 2: Cleaning of aluminum alloy pipes: Remove oil stains and attached impurities on the pipe surface through ultrasonic cleaning. Ultrasonic cleaning uses 95% alcohol as the cleaning solution, the cleaning temperature is 50°C, and the cleaning time is 30 minutes.

[0070] Step 3: Drying of aluminum alloy pipes: Place the cleaned aluminum alloy pipes in an oven for drying at a temperature of 80°C for 60 minutes.

[0071] Step 4: Prepare the high-temperature tape. Prepare a high-temperature tape of appropriate length according to the size of the aluminum alloy pipe. The width of the high-temperature tape is 100mm. Punch holes in the middle of the width of the high-temperature tape. The punching radius r is 2mm. The distance a between the center of the first hole and the starting point of the high-temperature tape is 30mm. The distance b between the centers of subsequent punches from the first hole is 62.8mm. The reserved length Y of the high-temperature tape is 1400mm.

[0072] Step 5: Assemble and fix the aluminum alloy pipe. Take out the cleaned and dried aluminum alloy pipe and align the two ends of the welding interface as close as possible. The widest part of the interface gap is X max The width of the tape is 0.18mm. Use the high-temperature tape prepared in step 4 to fix it. Align the middle of the width of the tape with the weld gap. Wrap it around the aluminum alloy pipe five times and then cut off the excess tape to leave four evenly distributed holes. Each hole corresponds to a tack welding position. The center of the hole reserved on the high-temperature tape is on the weld gap and the weld gap can be clearly seen through the hole. The effective field of view radius of each hole is 2mm.

[0073] Step 6: Position welding of aluminum alloy pipes. Place the fixed aluminum alloy pipes into the electron beam welder and further fix them with the side rotating chuck and ejector in the electron beam welder. After clamping, close the welding chamber door and position weld the aluminum alloy pipes through the holes reserved on the high-temperature tape. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and moving the gun motor so that the electron beam can bombard the welding gap on the aluminum alloy pipe through the holes on the high-temperature tape. Set the positioning welding process parameters as follows: the vacuum degree of the gun chamber is 5×10 -3 Pa, the vacuum degree of the welding chamber is 5×10 -3 The welding operation was carried out in sequence on four tack welding positions according to the same process parameters: Pa, filament current 24A, high voltage 70kV, welding beam current 15mA, gun distance 150mm, single down-beam beam duration 1s;

[0074] Step 7: Cleaning the aluminum alloy pipe: Remove the welded aluminum alloy pipe from the welding chamber of the electron beam welder and remove the high-temperature tape used to secure it. Then, perform ultrasonic cleaning to remove any residual adhesive and other impurities on the pipe surface. Ultrasonic cleaning uses 95% alcohol as the cleaning solution at a temperature of 70°C for 30 minutes. The cleaned pipe is then placed in an oven for drying at 80°C for 60 minutes.

[0075] Step 8: Formal welding of the welding gap of the aluminum alloy pipe. The aluminum alloy pipe cleaned and dried in step 7 is further fixed by the side rotating chuck and ejector in the electron beam welding machine. After clamping, close the welding chamber door. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and the gun moving motor so that the electron beam from the electron beam gun can bombard the welding gap position on the aluminum alloy pipe. Set the formal welding process parameters as follows: the vacuum degree of the gun chamber is 5×10 -3 Pa, the vacuum degree of the welding chamber is 5×10 -3 Pa, filament current 24A, high voltage 70kV, welding beam current 15mA, side chuck speed linear speed V 1000mm / min, welding time 17s, gun distance 150mm;

[0076] Step 9: After welding is completed, take the welded aluminum alloy pipe out of the welding chamber of the electron beam welder.

[0077] The conventional electron beam welding method requires inert gas shielded welding for positioning welding or requires complicated preparation and can only meet the needs of single-size tooling for positioning. The positioning welding scheme of the present invention can effectively avoid the risk of introducing impurities and forming defects in the conventional welding method of aluminum alloy during the positioning welding process. The positioning welding method involves a flexible fixing method, which can meet the welding positioning requirements of aluminum alloy pipes of different sizes, does not require customized tooling, is low in cost, and is simple to operate. It can meet the needs of aluminum alloy pipes of different lengths, different diameters, and different wall thicknesses by one-time welding. The weld is uniform and stable, the heat-affected zone is small, and defects such as insufficient weld penetration, poor forming, and slag inclusion and blistering during the aluminum alloy welding process are effectively avoided. The welding process is carried out in a high vacuum environment without the participation of a protective atmosphere or the addition of additional welding materials. The introduction of impurities and the influence of the external environment are avoided during the welding process, greatly improving the purity of the weld structure and the overall mechanical properties of the aluminum alloy pipe after welding. At the same time, the setting of digital process parameters can greatly reduce the influence of human factors on the welding process, and can stably achieve the repetition of the process and the uniformity and stability of the welding results.

[0078] A method for positioning and welding aluminum alloy pipes also includes a winding device for positioning two aluminum alloy pipes, punching holes in a high-temperature adhesive tape, and wrapping the high-temperature adhesive tape around the welding locations of the two aluminum alloy pipes. The winding device includes a base 1, on which are mounted two sets of rotating bases 2, each used to secure and position the two aluminum alloy pipes. After the rotating bases 2 secure the aluminum alloy pipes, the aluminum alloy pipes can rotate within the rotating bases 2.

[0079] A screw motor 4 is provided on the front side of the machine base 1, and the screw motor 4 is driven and connected to the screw 3, a screw slider 5 is provided on the screw 3, and the screw slider 5 is connected to the drive seat 6, and the drive seat 6 is connected to a rotating shaft 22, and the rear end of the rotating shaft 22 is connected to a driving block 7, and a drive shaft 8 is rotatably provided on the screw slider 5. A belt drive is adopted between the rotating shaft 22 and the drive shaft 8, a driving wheel 23 is connected to the rotating shaft 22, and a transmission wheel 20 is connected to the drive shaft 8, and a transmission belt 21 is connected between the driving wheel 23 and the transmission wheel 20.

[0080] A conductor rod 9 is provided on the rear side of the machine base 1, and a slider 10 is slidingly provided on the conductor rod 9. A moving block 11 is connected to the slider 10. The front side of the moving block 11 is rotatably connected to a rotating shaft 2 12. The front end of the rotating shaft 2 12 is connected to a driving block 2 13. A driven shaft 14 is rotatably provided on the front side of the slider 10. A belt drive is adopted between the driven shaft 14 and the rotating shaft 2 12. A transmission wheel 2 15 is connected to the driven shaft 14. A transmission wheel 3 16 is connected to the rotating shaft 2 12. A transmission belt 2 17 is connected between the transmission wheel 2 15 and the transmission wheel 3 16.

[0081] The rear end of drive shaft 8 is connected to linkage shaft 18, which is partially inserted into driven shaft 14. Several limit bars 19 are provided on the outer periphery of linkage shaft 18, and grooves are provided on the inner wall of driven shaft 14 to mate with the limit bars 19. Linkage shaft 18 on drive shaft 8 is capable of moving axially along driven shaft 14, ensuring that the drive shaft 8 and driven shaft 14 remain connected during movement. Furthermore, rotation of the drive shaft 8 drives the driven shaft 14 in sync with the linkage shaft 18.

[0082] Both driving block 1 7 and driving block 2 13 are frustum-shaped. The diameter of the end of driving block 1 7 and driving block 2 13 close to the aluminum alloy tube is smaller than the diameter of the end away from the aluminum alloy tube. This structural design allows driving block 1 7 and driving block 2 13 to more conveniently extend into the aluminum alloy tube and press against the inner wall of the aluminum alloy tube, thereby driving the aluminum alloy tube to rotate together.

[0083] The driving seat 6 includes a driven shaft 14, which is L-shaped. A rotating shaft 22 is rotatably provided on the vertical section of the driven shaft 14. The front end of the rotating shaft 22 is connected to a transmission ball wheel 55. The transmission ball wheel 55 is provided with four semicircular grooves 56 and four driving grooves 57. The four semicircular grooves 56 and the four driving grooves 57 are evenly distributed on the transmission ball wheel 55, and the semicircular grooves 56 and the driving grooves 57 are staggered.

[0084] A driving shaft 50 is rotatably mounted on the horizontal section of the driven shaft 14. The upper end of the driving shaft 50 is connected to the handwheel 49, and the lower end of the driving shaft 50 is connected to a rotating disk 51. A driving arc plate 52 is connected to the lower portion of the rotating disk 51. The diameter of the driving arc plate 52 is the same as the diameter of the semicircular groove 56. The central angle of the driving arc plate 52 is 180 degrees. A connecting bracket 53 is connected to the side of the rotating disk 51 opposite the driving arc plate 52. A driving rod 54 is connected to the connecting bracket 53.

[0085] The winding device further includes an unwinding frame 58 and a guide seat 43 . The tape roll 59 is rotatably arranged on the unwinding frame 58 , and the tape on the tape roll 59 passes through the guide seat 43 .

[0086] A punching mechanism is provided below the guide seat 43. The punching mechanism includes a base 24, on which a limit seat 39 is vertically provided. A lifting plate 40 is provided below the guide seat 43. A spring 1 46 is provided on the upper portion of the lifting plate 40. The limit seat 39 is provided with a driving mechanism for driving the lifting plate 40 to move up and down. A through hole is provided in the guide seat 43 at a position opposite the spring 1 46.

[0087] A second spring 48 is connected to the upper portion of the base 24 , and a buffer plate 47 is connected to the upper portion of the second spring 48 . The buffer plate 47 is located below the lifting plate 40 .

[0088] The driving mechanism includes a connecting rod 41 connected to the lifting plate 40, the connecting rod 41 is set through the limit seat 39, the connecting rod 41 can be lifted and lowered in the limit seat 39, the end of the connecting rod 41 away from the lifting plate 40 is connected to the rack 42, the base 24 is provided with a rotating base 36, the rotating base 36 is coaxially provided with a driven bevel gear 38 and a half gear 37, the half gear 37 can mesh with the rack 42, the base 24 is rotatably provided with a driven shaft 2 34 and a driving shaft 2 32, the driven shaft 2 34 away from the end of the driving shaft 2 32 is connected to the driving bevel gear 35, the driving bevel gear 38 ... 5 is meshed with the driven bevel gear 38. The side of the driving shaft 32 close to the driven shaft 34 is connected to the linkage shaft 44. A portion of the linkage shaft 44 is inserted into the driven shaft 34. A plurality of limiting bars 45 are provided on the outer periphery of the linkage shaft 44. The inner wall of the driven shaft 34 is provided with grooves that match the limiting bars 45. A spring 46 is provided on the outer sleeve of the limiting bar 45. One end of the spring 46 is connected to the driven shaft 34, and the other end of the spring 46 is connected to the driving shaft 32. The end of the driving shaft 32 away from the driven shaft 34 is connected to the driven gear 33.

[0089] A movable base 25 is slidably mounted on the base 24. This base 25 is connected to the driven shaft 14 and moves with it. A rotating shaft 3 26 is rotatably mounted on the movable base 25. The rear end of the rotating shaft 3 26 is connected to a driving gear 30. A retaining ring 31 is positioned behind the driving gear 30. A driven gear 33 meshes with the driving gear 30, with the front end of the driven gear 33 abutting the rear end of the retaining ring 31. The diameter of the driving gear 30 is four times that of the driven gear 33. For every 90-degree rotation of the driving gear 30, the driven gear 33 rotates one revolution, and the half gear 37 rotates one revolution. This results in the spring 1 46 of the punching mechanism rising and falling once for every 90-degree rotation of the pipe, ensuring that the punching frequency matches the movement frequency of the high-temperature tape. A belt drive is used between the rotating shaft 1 22 and the rotating shaft 3 26 . The rotating shaft 1 22 is connected to the driving wheel 2 27 , the rotating shaft 3 26 is connected to the transmission wheel 4 28 , and a transmission belt 3 29 is connected between the driving wheel 2 27 and the transmission wheel 4 28 .

[0090] Place two aluminum alloy pipes on two sets of rotating seats 2 respectively, and fix and position the aluminum alloy pipes by the two sets of rotating seats 2 so that the two ends of the welding interface are aligned and as close as possible, and the widest part of the interface gap is ≤0.2mm.

[0091] The screw motor 4 drives the screw 3 to rotate, which in turn drives the screw slider 5, causing the drive block 1 7 to be inserted into the front end of the front aluminum alloy tube. The moving block 11 then moves, causing the drive block 2 13 to be inserted into the rear end of the rear aluminum alloy tube. The drive base 6 drives the rotating shaft 1 22 to rotate, driving the drive blocks 1 7 and 2 13 together, thereby driving the two aluminum alloy tubes to rotate synchronously.

[0092] Turning handwheel 49 drives rotating disk 51 via driving shaft 50. Rotating disk 51 then drives driving arc plate 52 and connecting frame 53. The driving rod 54 on connecting frame 53 rotates and enters driving slot 57. The driving rod 54 acts on driving slot 57, driving ball wheel 55 to rotate. After the driving ball wheel 55 rotates 90 degrees, the driving rod 54 disengages from the driving slot 57, and the driving arc plate 52 enters the semicircular slot 56. Subsequently, when rotating disk 51 rotates, the driving arc plate 52 rotates within the semicircular slot 56, keeping the driving ball wheel 55 stationary. This coordination ensures that the driving ball wheel 55 remains stationary for a certain period of time after each 90-degree rotation. This also means that each time the aluminum alloy tube is rotated 90 degrees by drive block 7, the aluminum alloy tube remains stationary for a certain period of time.

[0093] Align the center of the high-temperature tape's width with the center of the gap between the two aluminum alloy pipes, then adhere the tape to the aluminum alloy pipe. The aluminum alloy pipe rotates, pulling the tape forward. Each 90-degree rotation of the aluminum alloy pipe causes the tape to move only 0.25πD, ensuring the center-to-center distance of each punched hole is 0.25πD. Furthermore, since the aluminum alloy pipe pauses for a certain period after each 90-degree rotation, the tape also pauses after each movement, leaving ample time for the punching mechanism to punch.

[0094] Before wrapping the tape around once, cut off the excess portion between the first hole and the end of the high-temperature tape so that the distance between the first hole and the end of the high-temperature tape is greater than r and less than 0.25πD-r, to avoid the length between the first hole and the end of the high-temperature tape being too long and blocking the hole.

[0095] The movement of driven shaft 14 drives the movable seat 25 synchronously, maintaining a belt transmission between rotating shaft 1 22 and rotating shaft 3 26. When rotating shaft 3 26 drives the driving gear 30, the driving gear 30 and the driven gear 33 cooperate to drive shaft 2 32 at a higher speed. Drive shaft 2 32 then rotates driven shaft 2 34 via linkage shaft 2 44. Drive shaft 2 34, in turn, rotates half gear 37 via the driving bevel gear 35 and the driven bevel gear 38. Due to the structure of half gear 37, when the toothed portion of half gear 37 engages with rack 42, it drives rack 42 upward. Rack 42 then raises the lifting plate 40 via connecting rod 41, which in turn raises spring 1 46 on the lifting plate 40, completing the perforation of the tape. When the toothless portion of half gear 37 rotates to the position of rack 42, the two no longer engage, and the lifting plate 40 descends under the action of gravity, causing rack 42 to return to its original position. The second spring 48 and the buffer plate 47 are provided to support the descending lifting plate 40 and play a buffering role.

[0096] A spring 1 46 is interposed between the second driven shaft 34 and the second driving shaft 32. Since the driving bevel gear 35 is engaged with the driven bevel gear 38, the position of the second driven shaft 34 is relatively fixed. The spring 1 46 exerts a force that pushes the second driving shaft 32 away from the second driven shaft 34. When the movable seat 25 moves the driving gear 30, the spring 1 46 keeps the driven gear 33 against the retaining ring 31, thereby ensuring that the driven gear 33 and the driving gear 30 remain engaged.

[0097] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A positioning welding method for aluminum alloy pipes, characterized in that: The following steps are involved: Step 1: Prepare two aluminum alloy pipes with an outer diameter of D. Use wire cutting and sandpaper polishing to make the welding interface ready for docking. The widest part of the interface gap is ≤0.2mm. After docking, the aluminum alloy pipes are straight as a whole, and the plane where the welding gap is located is perpendicular to the length direction of the pipes. Step 2: Use ultrasonic cleaning to remove oil stains and attached impurities on the surface of the pipe; Step 3: Place the cleaned aluminum alloy pipe in an oven for drying; Step 4: Punch holes in the middle of the high-temperature tape. The punch radius r is 2mm-3mm. The distance between the center of the first hole and the starting point of the high-temperature tape is greater than r and less than 0.25πD-r. The distance between the punch centers is 0.25πD. The reserved length of the high-temperature tape should be enough to wrap around the aluminum alloy pipe for more than 5 times. Step 5: Take out the aluminum alloy pipe dried in step 3, align and close the two ends of the welding interface, and make the widest part of the interface gap ≤0.2mm. Fix it with high-temperature tape, align the middle of the width of the high-temperature tape with the welding gap, and wrap it for more than 5 circles, leaving four evenly distributed holes, each hole corresponding to a positioning welding position; Position the two aluminum alloy pipes through a winding device, punch holes in the high-temperature tape, and wrap the high-temperature tape around the welding position of the two aluminum alloy pipes; The winding device comprises a machine base (1), on which two groups of rotating seats (2), a driving block 1 (7), a driving block 2 (13), and a driving seat (6) are arranged. The driving seat (6) comprises a rotating shaft 1 (22) and a driving shaft (50). The front end of the rotating shaft 1 (22) is connected to a transmission ball wheel (55). The transmission ball wheel (55) is provided with four semicircular grooves (56) and four driving grooves (57). The four semicircular grooves (56) and the four driving grooves (57) are evenly distributed on the transmission ball wheel (55). The semicircular grooves (56) and the driving grooves (57) are staggered. The lower end of the driving shaft (50) is connected to a rotating disk (51). The lower part of the disk (51) is connected to a driving arc plate (52), and the diameter of the driving arc plate (52) is the same as the diameter of the semicircular groove (56); the central angle of the driving arc plate (52) is 180 degrees, and the side of the rotating disk (51) opposite to the driving arc plate (52) is connected to a connecting frame (53), and the connecting frame (53) is connected to a driving rod (54); the transmission ball wheel (55) will stop for a certain period of time after each 90-degree rotation, so that each time the aluminum alloy pipe rotates 90 degrees, the tape adhered to the aluminum alloy pipe only moves 0.25πD each time, thereby ensuring that the distance between the centers of the holes punched each time is 0.25πD; Step 6: Place the fixed aluminum alloy pipe into the electron beam welder and further fix it with the side-rotating chuck and ejector in the electron beam welder. After clamping, close the welding chamber door and perform positioning welding on the aluminum alloy pipe through the holes reserved on the high-temperature tape. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and the gun moving motor so that the electron beam can bombard the welding gap on the aluminum alloy pipe through the holes on the high-temperature tape. Perform welding operations on the four positioning welding positions in sequence according to the same process parameters. Step 7: Take the aluminum alloy pipe with positioning welding out of the welding chamber of the electron beam welder, tear off the high-temperature tape used for fixing, and then use ultrasonic cleaning to remove the residual glue and other impurities on the surface of the pipe; put the cleaned pipe into the oven for drying; Step 8: The aluminum alloy pipe cleaned and dried in step 7 is further fixed by the side rotating chuck and ejector in the electron beam welding machine. After clamping, close the welding chamber door. Adjust the position of the electron beam gun and the workpiece by rotating the measuring chuck and the gun moving motor so that the electron beam from the electron beam gun can bombard the welding gap position on the aluminum alloy pipe. Set the formal welding process parameters as follows: gun chamber vacuum ≤ 5×10 -3 Pa, vacuum degree of welding chamber ≤5×10 -3 Pa, filament current is 22A-24A, high voltage is 68kV-80kV, welding beam current is 4mA-6mA per millimeter of pipe wall thickness, side rotation chuck speed linear speed V is 1000mm / min-1500mm / min, welding time is greater than πD / V, and gun distance is 150mm-200mm; Step 9: After welding is completed, take the welded aluminum alloy pipe out of the welding chamber of the electron beam welder.

2. The positioning welding method of an aluminum alloy pipe according to claim 1, characterized in that: In step 2, ultrasonic cleaning uses alcohol with a concentration of ≥95% as a cleaning solution, the cleaning temperature is 30°C-50°C, and the cleaning time is ≥30 minutes.

3. The positioning welding method of an aluminum alloy pipe according to claim 1, characterized in that: In step 3, the drying temperature is 80°C-100°C, and the drying time is ≥60 minutes.

4. The positioning welding method of an aluminum alloy pipe according to claim 1, characterized in that: In step 5, the center of the hole on the high-temperature tape is on the welding gap and the welding gap can be clearly seen through the hole. The effective field of view radius of each hole is ≥2mm.

5. The positioning welding method of an aluminum alloy pipe according to claim 1, characterized in that: In step 6, set the positioning welding process parameters as follows: gun chamber vacuum ≤ 5×10 -3 Pa, vacuum degree of welding chamber ≤5×10 -3 Pa, filament current is 22A-24A, high voltage is 68-80kV, welding beam current is 4mA-6mA per millimeter of pipe wall thickness, gun distance is 150mm-200mm, and single beam duration is 1s.

6. The positioning welding method of an aluminum alloy pipe according to claim 1, characterized in that: In step seven, ultrasonic cleaning uses alcohol with a concentration of ≥95% as a cleaning solution, the cleaning temperature is 50°C-70°C, and the cleaning time is ≥30 minutes.

7. A method for positioning welding of aluminum alloy pipes according to claim 6, characterized in that: In step seven, the drying temperature is 80° C.-100° C., and the drying time is ≥60 min.

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