A 7075 ultra-high-strength aluminum alloy butt welding process qualification device and a qualification process

Abstract

The application discloses a 7075 super-high-strength aluminum alloy butt welding process evaluation device, which comprises a bottom plate, a vertical stand pipe is fixedly arranged on the bottom plate, a connecting steel plate is fixedly arranged on the upper portion of the stand pipe, a first sleeve pipe is sleeved on the outer side of the stand pipe through a first locking screw rod, a notch is formed in the upper portion of the first sleeve pipe, two side connecting plates are fixedly arranged at the notch position and are locked through a second locking screw rod, a second sleeve pipe is transversely fixedly arranged at the front end of the two side connecting plates, a T-shaped plug-in plate is inserted into the inner side of the second sleeve pipe, the T-shaped plug-in plate comprises a U-shaped plate, a horizontal supporting plate is inserted into the inner side of the U-shaped plate and is fixed through a third locking screw rod, a U-shaped supporting groove and door-shaped frames which are respectively arranged on the two sides of the U-shaped supporting groove are fixedly arranged on the upper surface of the front end of the horizontal supporting plate, and a fourth locking screw rod is vertically arranged on each door-shaped frame. Through optimization of welding materials and process parameters, in combination with X-ray flaw detection and mechanical property detection, it is ensured that the welding seam meets the performance requirements of long-term heavy-load operation of a mechanical hand beam.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy welding technology, specifically relating to a 7075 ultra-high strength aluminum alloy butt welding process evaluation device and evaluation process. Background Technology

[0002] In the field of high-speed rail and heavy-duty wheel manufacturing, the double-tool CNC vertical wheel lathe is a core piece of equipment for special precision machining after heat treatment. For example, the Maanshan Iron and Steel RQQ production line can complete the rough and precision turning of wheel tread, rim, spokes and hub holes in one go through the double-tool synchronous turning technology. It can effectively correct heat treatment deformation and ensure high-precision machining of standard wheel profile, while also taking into account the efficiency of mass production and the stringent dimensional tolerances and fatigue performance requirements of railway products. It is an indispensable key piece of equipment for rail transit wheel manufacturing.

[0003] The mobile robotic arm, as the core supporting equipment for wheel handling in this dual-post CNC vertical wheel lathe, undertakes the task of precise positioning and transfer of wheels in and out of the machine tool. Due to long-term heavy-load cyclic operation, the structural stability of the original robotic arm beam has gradually become insufficient, directly affecting the positioning accuracy of wheel handling and the reliability of equipment operation. In the existing solutions, if a customized new spare part solution is adopted, there are problems of high procurement costs and long cycle time; if conventional welding repair is used, due to poor material and process matching, the weld is prone to failure, which cannot achieve the goal of low cost and long service life repair, and it is difficult to meet the process optimization requirements of mass production. To solve this problem, a reinforcement scheme of welding 7075 ultra-high strength aluminum alloy plates around the robotic arm beam is designed, utilizing its excellent specific strength characteristics to improve the structural strength and operational stability of the beam. However, before completing the welding repair online, the welding qualification process of the 7075 ultra-high strength aluminum alloy plate must be completed to ensure that all repaired welds meet all mechanical performance requirements for long-term use in wheel handling positioning. Existing problems: First, 7075 aluminum alloy, as an Al-Zn-Mg-Cu series ultra-high-strength aluminum alloy, has extremely poor weldability, exhibiting technical challenges such as high sensitivity to hot cracking, severe softening of the heat-affected zone, high porosity, and difficulty in removing the oxide film. In existing welding processes, the compositional compatibility between conventional welding materials and 7075 aluminum alloy is insufficient, leading to defects such as easy crystallization cracking in the weld, joint strength only 50-70% of the base material, and porosity exceeding 2%, making it difficult to meet the mechanical performance requirements of long-term heavy-load operation of the robotic arm beam. Second, there is currently a lack of process qualification equipment suitable for butt welding of 7075 ultra-high-strength aluminum alloy. Therefore, the key issues lie in the matching of welding materials and the process qualification equipment. The main approach is to rely on the pressure vessel non-destructive testing standard JB / T4730-2005 for X-ray flaw detection (Level II qualified) and subsequent mechanical property testing to determine the welding materials and process parameters. Therefore, it is necessary to design a 7075 ultra-high-strength aluminum alloy butt welding process qualification device and its welding qualification process. Summary of the Invention

[0004] This invention provides a 7075 ultra-high strength aluminum alloy butt welding process evaluation device and evaluation process. By optimizing the matching of welding materials and clarifying suitable process parameters, combined with X-ray flaw detection (Level II qualified) and subsequent mechanical property testing according to the JB / T4730-2005 pressure vessel non-destructive testing standard, it ensures that the weld repair meets the mechanical performance requirements of the robot beam under long-term heavy load operation, realizes low-cost and long-life reinforcement repair of the beam, and thus ensures the wheel handling positioning accuracy and equipment operation reliability, adapting to the process optimization needs of mass production of rail transit wheels.

[0005] The technical solution of this invention to solve the technical problem is as follows:

[0006] This invention provides a 7075 ultra-high strength aluminum alloy butt welding process evaluation device, which includes a base plate, a vertically fixed pipe at the center of the base plate, a connecting steel plate vertically fixed at the upper part of the vertical pipe, and a first sleeve adapted to the vertical pipe movably sleeved on the outer side of the middle part of the vertical pipe through a plurality of first locking screws. The upper part of the first sleeve has a slot corresponding to the connecting steel plate, and two side connecting plates are fixed at intervals at the slot. The two side connecting plates are respectively located on both sides of the connecting steel plate and locked to it by a plurality of second locking screws. A second sleeve is horizontally fixed at the front end of the two side connecting plates. A T-shaped insert plate is inserted into the inner side of the second sleeve. The T-shaped insert plate includes a U-shaped plate. A horizontal support plate is inserted into the inner side of the U-shaped plate and fixed by a plurality of third locking screws. A U-shaped support groove and a portal frame located on both sides of the U-shaped support groove are respectively fixed on the upper surface of the front end of the horizontal support plate. A fourth locking screw is vertically inserted through each portal frame.

[0007] Furthermore, the first sleeve has several vertically protruding screw holes, and the riser has several vertically protruding screw holes evenly distributed. The first locking screw passes through the corresponding screw holes of the first sleeve and the riser respectively to lock them together.

[0008] Furthermore, the second locking screw is disposed through one or both sides of the side connecting plate of the connecting steel plate.

[0009] Furthermore, the T-shaped insert also includes a connecting rod fixed to the rear of the U-shaped plate, the connecting rod being adapted to the inner side of the second sleeve and inserted into the inner side of the second sleeve.

[0010] Furthermore, the fourth locking screw is made of copper.

[0011] The evaluation process of the 7075 ultra-high strength aluminum alloy butt welding process evaluation device described in the above technical solution includes the following steps:

[0012] Clamping and fixing: According to the specifications of the U-shaped support groove and the position of the portal frame relative to the U-shaped support groove, prepare three sections of 7075 high-strength aluminum alloy tubes, and make bevels on the ends of the three sections of 7075 high-strength aluminum alloy tubes to be welded; place the three sections of 7075 high-strength aluminum alloy tubes horizontally in the U-shaped support groove and allow them to rotate 360°, then align the three sections of 7075 high-strength aluminum alloy tubes, and fix the 7075 high-strength aluminum alloy tubes by the fourth locking screws on both sides;

[0013] Pre-welding preparation: Clean the bevel of the end of the 7075 high-strength aluminum alloy pipe to be welded and the ER5356 welding wire used for welding with ethanol to remove oil, oxide layer and moisture, and then preheat both sides of the bevel to 80-100℃.

[0014] Layered welding: The bottom layer, filler layer, and capping layer are welded using a manual AC pulse TIG welding machine, 99.999% high-purity argon gas as shielding gas, and φ2.5mm ER5356 TIG welding wire. For the bottom layer welding, the upper half of the bevel is welded first, with a welding current of 150-170A and a voltage of 18-21V. The welding wire is not laterally oscillating. Narrow weld beads are used for multi-layer, segmented welding. After the weld is inspected and found to be defect-free, the fourth locking screw is loosened, and the 7075 high-strength aluminum alloy tube is rotated to the lower half before being locked again. The lower half of the bottom layer is welded in the same manner. After the bottom layer welding is completed, the filler layer and capping layer are welded using the same method as the bottom layer welding, with a welding current of 150-170A and a voltage of 18-21V. The interpass temperature is strictly controlled to ≤100℃. Defects are checked after each weld to ensure there are no defects before continuing welding. The capping layer is higher than the base material and smoothly transitions with it.

[0015] Post-weld treatment: After all welding is completed, the weld is covered with asbestos cloth and slowly cooled to room temperature. After removing the oxide layer and spatter from the weld surface, X-ray flaw detection and mechanical property testing are carried out in accordance with JB / T4730-2005 standard.

[0016] Furthermore, the bevel angle on one side is 30°.

[0017] Furthermore, the manual AC pulse TIG welding machine is a Panasonic pulse manual AC TIG welding machine.

[0018] Furthermore, the cover layer is no larger than 3mm.

[0019] Compared to existing technologies, the 7075 ultra-high strength aluminum alloy butt welding process evaluation device and evaluation process described in this invention have a simple structure, are easy to source and manufacture, have low investment costs, and are safe and easy to operate. Combined with the evaluation process, it can effectively meet the 7075 ultra-high strength aluminum alloy butt welding process evaluation, realize low-cost and long-life reinforcement and repair of the robot arm beam, thereby ensuring the wheel handling positioning accuracy and equipment operation reliability, adapting to the process optimization needs of mass production of rail transit wheels, and also providing a scientific reference for other special types of welding. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the 7075 ultra-high strength aluminum alloy butt welding process evaluation device of this application.

[0021] Figure 2 This is a front view of the 7075 ultra-high strength aluminum alloy butt welding process evaluation device of this application;

[0022] In the diagram: 1. Base plate; 2. Riser; 3. First sleeve; 4. First locking screw; 5. Connecting steel plate; 6. Second sleeve; 7. Second locking screw; 8. T-shaped insert; 81. U-shaped plate; 82. Connecting rod; 9. Horizontal support plate; 10. Third locking screw; 11. U-shaped support groove; 12. 7075 high-strength aluminum alloy tube; 13. Bevel; 14. Portal frame; 15. Fourth locking screw; 16. Side connecting plate. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this disclosure pertains. The terms "upper," "lower," "left," "right," "front," and "back" used in the present patent application specification and claims are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship also changes accordingly. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Any aspects not detailed in this invention are well-known to those skilled in the art.

[0024] Example 1

[0025] like Figure 1-2As shown, this invention provides a 7075 ultra-high strength aluminum alloy butt welding process evaluation device, which includes a base plate 1, preferably machined from a 100mm thick steel plate, and preferably circular or square, such as a φ1000mm circular plate. A vertical pipe 2 is welded to the center of the base plate 1, preferably machined from a φ76mm×8mm steel pipe, with a height of approximately 800mm. A connecting steel plate 5 is vertically welded to the upper part of the vertical pipe 2, preferably machined from a 25mm thick steel plate, with dimensions preferably 400mm×400mm×25mm. A first sleeve 3, adapted to the middle outer side of the vertical pipe 2, is movably fitted thereon, and the two are fixed together by a plurality of first locking screws 4. The upper part of the first sleeve 3 has a slot corresponding to the connecting steel plate 5, and two side connecting plates 16 are fixed at intervals at the slot. The two side connecting plates 16 are located on both sides of the connecting steel plate 5 and are locked to the connecting steel plate 5 by several second locking screws 7 passing through the side connecting plates. The front end of the two side connecting plates 16 is horizontally fixed with a second sleeve 6. A T-shaped insert plate 8 is inserted into the inner side of the second sleeve 6. The T-shaped insert plate 8 includes a U-shaped plate 81 with the opening facing forward. A horizontal support plate 9 is inserted into the inner side. At the same time, the upper part of the U-shaped plate 81 is fixed to the horizontal support plate 9 by several third locking screws 10 passing through it. The horizontal support plate 9 is preferably made of 25mm thick steel plate. The upper surface of the front end of the horizontal support plate 9 is fixed with a U-shaped support groove 11 and a portal frame 14 located on both sides of the U-shaped support groove 11 and spanning above the U-shaped support groove 11. Each portal frame 14 is vertically connected with a fourth locking screw 15, which is used to lock the 7075 ultra-high strength aluminum alloy 12 during welding.

[0026] In this embodiment, the first sleeve 3 has 1-2 vertically protruding screw holes that are compatible with the first locking screw 4, and the riser 2 has multiple vertically protruding screw holes that are compatible with the first locking screw 4. The first locking screw 4 passes through the corresponding screw holes of the first sleeve 3 and the riser 2 respectively to lock the two together. With this structure, the vertical height of the first sleeve 3 can be adjusted according to the welding requirements, and then locked by the first locking screw 4.

[0027] In this embodiment, the second locking screw 7 is disposed through the side connecting plate 16 on one or both sides of the connecting steel plate 5. By screwing the second locking screw 7, its front end is pressed against the connecting steel plate 5 to ensure the stability of the entire device.

[0028] In this embodiment, the T-shaped insert plate 8 also includes a connecting rod 82 fixed to the rear of the U-shaped plate 81. The connecting rod 82 is adapted to the inner side of the second sleeve 6 and inserted into the inner side of the second sleeve 6 for easy connection.

[0029] In this embodiment, the fourth locking screw 15 is preferably made of copper to ensure the amount of shrinkage deformation during butt welding of 7075 ultra-high strength aluminum alloy.

[0030] In application, first fix the base plate 1 horizontally on the ground, then weld and fix the riser 2 at the center of the base plate 1. After welding and fixing the side connecting plate 16 on both sides of the groove of the first sleeve 3, move the first sleeve 3 up and down to the appropriate position on the riser 2 and fix it with the first locking screw 4. Weld and fix the connecting steel plate 5 at the upper end of the riser 2, and tighten the side connecting plate 16 and the connecting steel plate 5 with the second locking screw 7. Install the second sleeve 6 at the front end of the side connecting plate 16, insert the T-shaped insert 8 into the second sleeve 6, and then... The U-shaped plate 81 of the insert plate 8 is horizontally inserted into the horizontal support plate 9 and locked by the third locking screw 10. The U-shaped support groove 11 and the portal frame 14 are then welded and fixed on the horizontal support plate 9. The U-shaped support groove 11 and the portal frame 14 can also be pre-welded to the horizontal support plate 9. Then, the three sections of 7075 ultra-high strength aluminum alloy tube 12 are horizontally installed in the U-shaped support groove 11 and can rotate 360°. The 7075 ultra-high strength aluminum alloy tube 12 is then pressed by the portal frame 14 through the fourth locking screw 15 to ensure the amount of shrinkage deformation during welding. Finally, the upper half of the bevel 13 of the 7075 ultra-high strength aluminum alloy tube 12 is welded first, then the fourth locking screw 15 is loosened, and the 7075 ultra-high strength aluminum alloy tube 12 is rotated to complete the welding of the remaining lower half. After all welding is completed, the fourth locking screw 15 is loosened again, and the welded 7075 ultra-high strength aluminum alloy tube 12 is taken out as the weldment for process evaluation.

[0031] Example 2:

[0032] The evaluation process of a 7075 ultra-high strength aluminum alloy butt welding process evaluation device in Example 1 includes the following steps:

[0033] Clamping and fixing: According to the specifications of the U-shaped support groove 11 and the position of the portal frame 14 relative to the U-shaped support groove 11, prepare three sections of 7075 high-strength aluminum alloy tubes 12. Make a bevel 13 on the ends of the three sections of 7075 high-strength aluminum alloy tubes 12 to be welded. The bevel 13 has a single-sided angle of 30°, which can form a V-shaped bevel. Place the three sections of 7075 high-strength aluminum alloy tubes 12 horizontally in the U-shaped support groove 11 and allow them to rotate 360°. Then align the three sections of 7075 high-strength aluminum alloy tubes 12 and fix them with the fourth locking screws 15 on both sides.

[0034] Preparation before welding:

[0035] 1) Welding equipment: Panasonic pulse manual AC TIG welding machine, shielding gas high-purity argon with a purity of 9999.9%, welding material: ER5356 TIG welding wire, φ2.5mm.

[0036] 2) Welding technical requirements: The weld overlay of the single-sided weld with double-sided forming is fused with the base material, the weld is free of any welding defects and meets the design dimensions.

[0037] 3) Auxiliary facilities: file, hammer, flat chisel, mask, template, thermometer, magnifying glass, stainless steel wire brush.

[0038] 4) Welding material: 7075 ultra-high strength aluminum alloy.

[0039] 5) Pre-welding requirements: The welding area and welding materials must be free of oil, oxide layer, moisture, etc., and the metal luster must be exposed. Before welding, the bevel 13 and welding wire to be welded must be cleaned with ethanol.

[0040] 6) Welding position: Horizontal rotation welding 1G.

[0041] 7) Before welding, preheat both sides of the groove 13 with oxy-acetylene at 80-100℃ to drive away moisture and reduce thermal stress.

[0042] Welding process parameters

[0043]

[0044] Layered welding: A manual AC pulse TIG welding machine, 99.999% high-purity argon as shielding gas, and φ2.5mm ER5356 TIG welding wire are used for the bottom layer, filler layer, and capping layer welding. For the bottom layer welding, the upper half of bevel 13 is welded first, with a welding current of 150-170A and a voltage of 18-21V. The welding wire is not oscillated laterally to reduce heat input. Narrow weld beads and multi-layer segmented welding are used. While ensuring good fusion, low current and slow welding speed are employed to avoid defects such as slag inclusions and incomplete fusion. After the weld is inspected and found to be defect-free, the welding is then completed. Open the fourth locking screw 15 and rotate the 7075 high-strength aluminum alloy tube 12 to the lower half, then lock it. Then, complete the welding of the bottom layer of the lower half in the same way. After the bottom layer welding is completed, weld the filler layer and cover layer in the same way as the bottom layer welding, using a welding current of 150-170A and a voltage of 18-21V. At the same time, strictly control the interlayer temperature to ≤100℃. A temperature measuring instrument can be used for monitoring. Check for defects after each weld. Only continue to the next layer welding after ensuring that there are no defects. The cover layer is higher than the base material, but not more than 3mm higher, and smoothly transitions with the base material.

[0045] Post-weld treatment: After all welding is completed, the weld is covered with asbestos cloth or other insulation material and slowly cooled to room temperature. The oxide layer and spatter on the weld surface are removed with a stainless steel brush, and then a visual inspection is performed to confirm that there are no defects. X-ray flaw detection (Level II qualified) and subsequent mechanical property testing are carried out according to JB / T4730-2005 standard to determine the welding materials and process parameters, thereby ensuring that the repaired weld can meet the long-term use requirements, effectively reducing maintenance costs, and ensuring that the continuous and stable operation of production fully meets the requirements before being put into use.

Claims

1. A device for evaluating the butt welding process of 7075 ultra-high strength aluminum alloy, characterized in that, The base plate (1) includes a vertically fixed riser (2) at its center. A connecting steel plate (5) is vertically fixed on the upper part of the riser (2). A first sleeve (3) is movably fitted on the outer side of the middle part of the riser (2) by a number of first locking screws (4). The upper part of the first sleeve (3) has a slot corresponding to the connecting steel plate (5), and two side connecting plates (16) are fixed at intervals at the slot. The two side connecting plates (16) are located on both sides of the connecting steel plate (5) and are locked to it by a number of second locking screws (7). The front end of the side connecting plate (16) is horizontally fixed with a second sleeve (6), and a T-shaped insert plate (8) is inserted inside the second sleeve (6). The T-shaped insert plate (8) includes a U-shaped plate (81). A horizontal support plate (9) is inserted inside the U-shaped plate (81) and fixed by several third locking screws (10). The upper surface of the front end of the horizontal support plate (9) is respectively fixed with a U-shaped support groove (11) and a gate frame (14) located on both sides of the U-shaped support groove (11). A fourth locking screw (15) is vertically inserted through each gate frame (14).

2. The 7075 ultra-high strength aluminum alloy butt welding process evaluation device according to claim 1, characterized in that, The first sleeve (3) has several vertically protruding screw holes, and the riser (2) has several vertically protruding screw holes evenly distributed. The first locking screw (4) passes through the corresponding screw holes of the first sleeve (3) and the riser (2) respectively to lock the two together.

3. The 7075 ultra-high strength aluminum alloy butt welding process evaluation device according to claim 1, characterized in that, The second locking screw (7) is disposed through the side connecting plate (16) on one or both sides of the connecting steel plate (5).

4. The 7075 ultra-high strength aluminum alloy butt welding process evaluation device according to claim 1, characterized in that, The T-shaped insert (8) also includes a connecting rod (82) fixed to the rear of the U-shaped plate (81), the connecting rod (82) being adapted to the inner side of the second sleeve (6) and inserted into the inner side of the second sleeve (6).

5. The 7075 ultra-high strength aluminum alloy butt welding process evaluation device according to claim 1, characterized in that, The fourth locking screw (15) is made of copper.

6. The evaluation process of the 7075 ultra-high strength aluminum alloy butt welding process evaluation device according to any one of claims 1-5, characterized in that, Includes the following steps: Clamping and fixing: According to the specifications of the U-shaped support groove (11) and the position of the portal frame (14) relative to the U-shaped support groove (11), prepare three sections of 7075 high-strength aluminum alloy tubes (12), and open the bevel (13) at the ends of the three sections of 7075 high-strength aluminum alloy tubes (12) to be welded; place the three sections of 7075 high-strength aluminum alloy tubes (12) horizontally in the U-shaped support groove (11) and rotate 360°, then align the three sections of 7075 high-strength aluminum alloy tubes (12), and fix the 7075 high-strength aluminum alloy tubes (12) by the fourth locking screws (15) on both sides; Pre-welding preparation: Clean the bevel (13) of the end to be welded of the 7075 high-strength aluminum alloy pipe (12) and the ER5356 welding wire used for welding with ethanol to remove oil, oxide layer and moisture, and then preheat both sides of the bevel to 80-100℃. Layered welding: The bottom layer, filler layer and cover layer are welded using a manual AC pulse argon arc welding machine, 99.999% high-purity argon gas as shielding gas and φ2.5mm ER5356 argon arc welding wire. When welding the bottom layer, the upper half of the bevel (13) is welded first, with a welding current of 150-170A and a voltage of 18-21V. The welding wire is not swung laterally. Narrow weld beads are used for multi-layer segmented welding. After the weld is inspected and found to be defect-free, the fourth locking screw (15) is loosened and the 7075 high-strength aluminum alloy tube (12) is rotated to the lower half and then locked. The bottom layer of the lower half is welded in the same way. After the bottom layer is welded, the filler layer and cover layer are welded in the same way as the bottom layer, with a welding current of 150-170A and a voltage of 18-21V. At the same time, the interlayer temperature is strictly controlled to be ≤100℃. Defect inspection is carried out after each weld to ensure that there are no defects before continuing to weld. The cover layer is higher than the base material and smoothly transitions with the base material. Post-weld treatment: After all welding is completed, the weld is covered with asbestos cloth and slowly cooled to room temperature. After removing the oxide layer and spatter from the weld surface, X-ray flaw detection and mechanical property testing are carried out in accordance with JB / T4730-2005 standard.

7. The evaluation process according to claim 6, characterized in that, The bevel (13) has a single-sided angle of 30°.

8. The evaluation process according to claim 6, characterized in that, The manual AC pulse TIG welding machine is a Panasonic pulse manual AC TIG welding machine.

9. The evaluation process according to claim 6, characterized in that, The cover layer is no more than 3mm thick.

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