Method for repairing swing laser welding hot cracks

Abstract

The invention discloses a method for repairing a swing laser welding hot crack, which comprises the following steps of: 1, designing a light path: designing two paths of laser, placing one laser beam on a fixing device for fixing, and placing the other laser beam on swing equipment for swinging as an auxiliary; secondly, parameter adjustment is conducted, wherein parameter setting is conducted on the swing amplitude and swing frequency of swing laser welding; step 3, optimizing temperature field distribution; according to the method, the fixing device and the swing equipment are arranged, one laser beam is fixed through the fixing device, the other laser beam is fixed through the swing equipment, double-beam laser welding is carried out on a product, then surface machining is carried out, a low-angle grain boundary is formed along a fusion line, grains are refined at a welding center, and the welding quality of the product is improved. And therefore, internal hot cracks are reduced by adjusting microscopic structures of base metal and welding metal, the use requirements of people are met, and the practicability is high.

Description

Technical Field

[0001] The invention relates to the technical field of swing laser welding, in particular to a method for repairing swing laser welding thermal cracks. Background Art

[0002] High-toughness aluminum alloy has high comprehensive mechanical properties and is mainly used for integrated aluminum alloy die-castings such as new energy vehicle battery packs and chassis and other large welded structural parts. Its welding methods TIG welding and MIG welding have the advantages of fast welding speed, high energy density, suitability for complex and changeable trajectories, easy production, simple operation, low cost, etc. They are widely used, but are prone to defects such as thermal cracks and pores.

[0003] Oscillating laser welding technology is an effective method for repairing thermal cracks. By adjusting the oscillation parameters of the laser, such as oscillation frequency and amplitude, thermal cracks in the welding process can be significantly reduced. This method optimizes the energy distribution of the laser and the flow of the molten pool during welding, thereby enhancing molten pool convection and reducing porosity crack defects.

[0004] However, conventional swing laser welding has the following disadvantages: At present, the swing laser welding method cannot solve the problems of welding cracks and pore defects of high-strength titanium alloys and has low practicality. Summary of the invention

[0005] The purpose of the present invention is to provide a method for repairing thermal cracks in swing laser welding to solve the problems of welding cracks and porosity defects mentioned in the above background technology that cannot be solved by current traditional welding methods.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for repairing thermal cracks in swing laser welding, comprising the following steps: Step 1: Design the optical path: Design a dual-path laser, where one laser beam is fixed on a fixed device, and the other laser beam is placed on a swinging device to swing as an auxiliary; Step 2: Parameter adjustment: set the parameters of the swing amplitude and swing frequency of the swing laser welding; Step 3: Optimize the temperature field distribution: through dual-path laser swing, drive the melt to replenish at the solidification front of the tail of the molten pool and sense the temperature in real time to ensure that the thermal cracks are repaired intact; Step 4: Deliver shielding gas: Deliver shielding gas in real time during the welding process until the product welding is completed.

[0007] As a preferred technical solution of the present invention, the fixing device in step one includes a fixed base and a laser table, the top of the fixed base is fixedly connected to the bottom of the laser table, a turntable is rotatably connected to one side of the top of the laser table, a height frame is fixedly installed on the top of the turntable, a height slot is opened on one side of the height frame, a lifting cylinder is fixedly installed on the bottom end of the inner wall of the height slot, a lifting platform is fixedly installed on the movable end of the lifting cylinder, a clamping mechanism is fixedly installed on one side of the lifting platform, a display screen is fixedly installed on the other side of the top of the laser table, the lifting cylinder performs telescopic movement, the lifting platform slides along the height slot to adjust the height of the fixed laser beam, and the turntable rotates relative to the laser table to adjust the angle of the fixed laser beam.

[0008] As a preferred technical solution of the present invention, the clamping mechanism includes a motor box and a connecting platform, one side of the connecting platform is fixedly connected to one side of the motor box, and the other side of the connecting platform is provided with a movable groove, the inside of the movable groove is rotatably connected with a screw rod, the surface of the screw rod is threadedly connected with a movable block slidably connected to the movable groove, one side of the two movable blocks is fixedly installed with a clamping plate, a stepper motor is fixedly installed inside the motor box, an active umbrella-shaped bevel gear is fixedly installed on the output end of the stepper motor through the motor box and the connecting platform, a driven umbrella-shaped bevel gear is fixedly installed in the middle of the screw rod, and the active umbrella-shaped bevel gear The outer side of the wheel is meshed with the outer side of the driven umbrella-shaped bevel gear, and the stepper motor starts after being energized. The stepper motor drives the active umbrella-shaped bevel gear to rotate, and the active umbrella-shaped bevel gear contacts the driven umbrella-shaped bevel gear, and the driven umbrella-shaped bevel gear drives the lead screw to rotate. The lead screw has two threads in opposite directions with its own center line as the dividing line. The threads on the surface of the lead screw match the threads on the inner walls of the two movable blocks. The two movable blocks are limited by movable grooves that match their shapes and sizes, so the two movable blocks slide relative to each other along the lead screw. During the sliding process of the movable block, the splint is driven to move synchronously, and the splint clamps and fixes it from both sides of the fixed laser beam.

[0009] As a preferred technical solution of the present invention, the bottom end of one side of the connecting platform is fixedly connected to the lifting platform, and the clamping mechanism is installed on the lifting platform through the connecting platform.

[0010] As a preferred technical solution of the present invention, the swinging device includes a mounting table and a movable seat, the top of the mounting table is fixedly connected to the bottom of the movable seat, the bottom end of the inner wall of the movable seat is rotatably connected to a first rotating shaft, the top end of the inner wall of the movable seat is rotatably connected to a second rotating shaft, a direction rod is fixedly installed in the middle of the first rotating shaft, the middle part of the direction rod is slidably connected to a swinging table, a suction cup plate is fixedly installed on one side of the swinging table, and the swinging laser is fixed on the suction cup plate by the adsorption of the suction cup plate itself.

[0011] As a preferred technical solution of the present invention, a pull rod is fixedly installed in the middle of the second rotating shaft, a limit plate is fixedly installed on the top of the direction rod, and the end of the pull rod away from the second rotating shaft is connected to the side opposite to the swing table. During the rotation of the second rotating shaft, the second rotating shaft drives the pull rod to move synchronously, the pull rod drives the swing table to slide relative to the direction rod, and the direction rod drives the first rotating shaft to rotate relative to the movable seat.

[0012] As a preferred technical solution of the present invention, the swing frequency in step 2 is specifically 90-150 Hz, and the swing amplitude in step 2 is a circular swing.

[0013] As a preferred technical solution of the present invention, the protective gas in step 4 is CO2.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: by setting a fixing device and a swinging device, the fixing device fixes one laser beam, and the swinging device fixes another laser beam, the product is first subjected to dual-beam laser welding and then surface processing, low-angle grain boundaries are formed along the fusion line, and the grains are refined at the welding center, thereby reducing internal thermal cracks by adjusting the microstructure of the base material and the weld metal, meeting people's usage needs and having high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a flow chart of the present invention; Figure 2 A side view of the optical path designed for the present invention; Figure 3 It is a partial schematic diagram of the fixing device of the present invention; Figure 4 is a cross-sectional view of the fixing device of the present invention; Figure 5 is a cross-sectional view of the clamping mechanism of the present invention; Figure 6 It is a side view of the swing device of the present invention.

[0016] In the figure: 1. fixing device; 2. swinging device; 3. fixed base; 4. laser table; 5. turntable; 6. height frame; 7. height slot; 8. lifting platform; 9. lifting cylinder; 10. display screen; 11. clamping mechanism; 111. motor box; 112. stepping motor; 113. connecting platform; 114. movable block; 115. clamping plate; 116. screw rod; 117. driven umbrella-shaped bevel gear; 118. active umbrella-shaped bevel gear; 119. movable slot; 12. mounting platform; 13. first rotating shaft; 14. movable seat; 15. second rotating shaft; 16. pull rod; 17. limit plate; 18. direction rod; 19. swinging platform; 20. suction cup plate. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 work are within the scope of protection of the present invention.

[0018] See also Figure 1-6 The present invention provides a method for repairing thermal cracks in swing laser welding, comprising the following steps: Step 1, design the optical path: design a dual-path laser, in which one laser beam is fixed on the fixing device 1, and the other laser beam is placed on the swinging device 2 to swing as an auxiliary; Step 2: Parameter adjustment: set the parameters of the swing amplitude and swing frequency of the swing laser welding; Step 3: Optimize the temperature field distribution: through dual-path laser swing, drive the melt to replenish at the solidification front of the tail of the molten pool and sense the temperature in real time to prevent thermal cracks; Step 4: Deliver shielding gas: Deliver shielding gas in real time during the welding process until the product welding is completed.

[0019] In step one, the fixing device 1 includes a fixed base 3 and a laser table 4, the top of the fixed base 3 is fixedly connected to the bottom of the laser table 4, one side of the top of the laser table 4 is rotatably connected with a turntable 5, the top of the turntable 5 is fixedly installed with a height frame 6, one side of the height frame 6 is provided with a height slot 7, the bottom end of the inner wall of the height slot 7 is fixedly installed with a lifting cylinder 9, the movable end of the lifting cylinder 9 is fixedly installed with a lifting platform 8, one side of the lifting platform 8 is fixedly installed with a clamping mechanism 11, and the other side of the top of the laser table 4 is fixedly installed with a display screen 10, the lifting cylinder 9 performs telescopic movement, the lifting platform 8 slides along the height slot 7 to adjust the height of the fixed laser beam, and the turntable 5 rotates relative to the laser table 4 to adjust the angle of the fixed laser beam.

[0020] The clamping mechanism 11 includes a motor box 111 and a connecting platform 113, one side of the connecting platform 113 is fixedly connected to one side of the motor box 111, and the other side of the connecting platform 113 is provided with a movable groove 119, the inside of the movable groove 119 is rotatably connected with a screw rod 116, the surface of the screw rod 116 is threadedly connected with a movable block 114 that is slidably connected to the movable groove 119, and one side of the two movable blocks 114 is fixedly installed with a clamping plate 115, the inside of the motor box 111 is fixedly installed with a stepping motor 112, the output end of the stepping motor 112 passes through the motor box 111 and the connecting platform 113 and is fixedly installed with an active umbrella-shaped bevel gear 118, the middle part of the screw rod 116 is fixedly installed with a driven umbrella-shaped bevel gear 117, and the outer side of the active umbrella-shaped bevel gear 118 is connected to the driven umbrella-shaped bevel gear The outer side of the wheel 117 is meshed and connected, and the stepper motor 112 is started after being energized. The stepper motor 112 drives the active umbrella-shaped bevel gear 118 to rotate, and the active umbrella-shaped bevel gear 118 contacts the driven umbrella-shaped bevel gear 117. The driven umbrella-shaped bevel gear 117 drives the screw rod 116 to rotate. The screw rod 116 has two threads in opposite directions with its own center line as the dividing line. The threads on the surface of the screw rod 116 match the threads on the inner walls of the two movable blocks 114. The two movable blocks 114 are limited by the movable groove 119 whose shape and size match each other, so the two movable blocks 114 slide relatively along the screw rod 116. During the sliding process of the movable block 114, the clamping plate 115 is driven to move synchronously, and the clamping plate 115 clamps and fixes it from both sides of the fixed laser beam.

[0021] The bottom end of one side of the connecting platform 113 is fixedly connected to the lifting platform 8 , and the clamping mechanism 11 is installed on the lifting platform 8 through the connecting platform 113 .

[0022] The swing device 2 includes a mounting platform 12 and a movable seat 14, the top of the mounting platform 12 is fixedly connected to the bottom of the movable seat 14, the bottom end of the inner wall of the movable seat 14 is rotatably connected to a first rotating shaft 13, the top end of the inner wall of the movable seat 14 is rotatably connected to a second rotating shaft 15, a direction rod 18 is fixedly installed in the middle of the first rotating shaft 13, a swing platform 19 is slidably connected in the middle of the direction rod 18, a suction cup plate 20 is fixedly installed on one side of the swing platform 19, and the swinging laser is fixed on the suction cup plate 20 by the adsorption of the suction cup plate 20 itself.

[0023] A pull rod 16 is fixedly installed in the middle of the second rotating shaft 15, and a limiting plate 17 is fixedly installed on the top of the direction rod 18. The end of the pull rod 16 away from the second rotating shaft 15 is connected to the side opposite to the swing table 19. During the rotation of the second rotating shaft 15, the second rotating shaft 15 drives the pull rod 16 to move synchronously, the pull rod 16 drives the swing table 19 to slide relative to the direction rod 18, and the direction rod 18 drives the first rotating shaft 13 to rotate relative to the movable seat 14.

[0024] The swing frequency in step 2 is specifically 90-150 Hz, and the swing amplitude in step 2 is a circular swing.

[0025] In step 4, the protective gas is CO2.

[0026] In the present invention, the lifting cylinder 9 performs telescopic movement, the lifting platform 8 slides along the height slot 7 to adjust the height of the fixed laser beam, the turntable 5 rotates relative to the laser platform 4 to adjust the angle of the fixed laser beam, and the stepper motor 112 is powered on and started, and the stepper motor 112 drives the active umbrella-shaped bevel gear 118 to rotate, and the active umbrella-shaped bevel gear 118 contacts the driven umbrella-shaped bevel gear 117, and the driven umbrella-shaped bevel gear 117 drives the screw rod 116 to rotate. The screw rod 116 is provided with two threads in opposite directions with its own center line as the dividing line, and the threads on the surface of the screw rod 116 match the threads on the inner walls of the two movable blocks 114. The two movable blocks 114 are limited by the movable slot 119 whose shape and size match each other, so the two movable blocks 114 slide relatively along the screw rod 116. During the sliding of the movable block 114, the clamping plate 115 is driven to move synchronously. The clamping plate 115 clamps and fixes the fixed laser beam from both sides. During the rotation of the second rotating shaft 15, the second rotating shaft 15 drives the pull rod 16 to move synchronously. The pull rod 16 drives the swing table 19 to slide relative to the direction rod 18, and the direction rod 18 drives the first rotating shaft 13 to rotate relative to the movable seat 14, so as to adjust the swinging path of the swinging laser beam. The swinging laser is fixed on the suction cup plate 20 by the adsorption of the suction cup plate 20 itself, and the swing amplitude and swing frequency of the swinging laser welding are set. Through the dual-path laser swing, the melt is driven to replenish and the temperature is sensed in real time at the solidification front of the tail of the molten pool to prevent the occurrence of thermal cracks. During the welding process, the protective gas is delivered in real time until the product welding is completed.

[0027] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for repairing thermal cracks in swing laser welding, characterized in that: The following steps are involved: Step 1: Design the optical path: Design a dual-path laser, wherein one laser beam is fixed on a fixing device (1), and the other laser beam is placed on a swinging device (2) to swing as an auxiliary; Step 2: Parameter adjustment: set the parameters of the swing amplitude and swing frequency of the swing laser welding; Step 3: Optimize the temperature field distribution: through dual-path laser swing, drive the melt to replenish at the solidification front of the tail of the molten pool and sense the temperature in real time to ensure that the thermal cracks are repaired intact; Step 4: Deliver shielding gas: Deliver shielding gas in real time during the welding process until the product welding is completed.

2. The method for repairing thermal cracks in swing laser welding according to claim 1, characterized in that: The fixing device (1) in step 1 comprises a fixing base (3) and a laser table (4), the top end of the fixing base (3) is fixedly connected to the bottom end of the laser table (4), one side of the top end of the laser table (4) is rotatably connected to a turntable (5), the top end of the turntable (5) is fixedly mounted with a height frame (6), one side of the height frame (6) is provided with a height slot (7), the bottom end of the inner wall of the height slot (7) is fixedly mounted with a lifting cylinder (9), the movable end of the lifting cylinder (9) is fixedly mounted with a lifting platform (8), one side of the lifting platform (8) is fixedly mounted with a clamping mechanism (11), and the other side of the top end of the laser table (4) is fixedly mounted with a display screen (10).

3. The method for repairing thermal cracks in swing laser welding according to claim 2, characterized in that: The clamping mechanism (11) comprises a motor box (111) and a connecting platform (113), one side of the connecting platform (113) being fixedly connected to one side of the motor box (111), and the other side of the connecting platform (113) being provided with a movable groove (119), the interior of the movable groove (119) being rotatably connected to a screw rod (116), the surface of the screw rod (116) being threadedly connected to a movable block (114) slidably connected to the movable groove (119), and the two movable blocks (114) A clamping plate (115) is fixedly mounted on one side of each of the motor boxes (111), a stepping motor (112) is fixedly mounted inside the motor box (111), an active umbrella-shaped bevel gear (118) is fixedly mounted on the output end of the stepping motor (112) through the motor box (111) and the connecting platform (113), a driven umbrella-shaped bevel gear (117) is fixedly mounted on the middle of the lead screw (116), and the outer side of the active umbrella-shaped bevel gear (118) is meshingly connected with the outer side of the driven umbrella-shaped bevel gear (117).

4. The method for repairing thermal cracks in swing laser welding according to claim 3 is characterized in that: The bottom end of one side of the connecting platform (113) is fixedly connected to the lifting platform (8).

5. The method for repairing thermal cracks in swing laser welding according to claim 1, characterized in that: The swing device (2) comprises a mounting platform (12) and a movable seat (14), the top end of the mounting platform (12) is fixedly connected to the bottom end of the movable seat (14), the bottom end of the inner wall of the movable seat (14) is rotatably connected to a first rotating shaft (13), the top end of the inner wall of the movable seat (14) is rotatably connected to a second rotating shaft (15), a direction rod (18) is fixedly installed in the middle of the first rotating shaft (13), the middle of the direction rod (18) is slidably connected to a swing platform (19), and a suction cup plate (20) is fixedly installed on one side of the swing platform (19).

6. The method for repairing thermal cracks in swing laser welding according to claim 5, characterized in that: A pull rod (16) is fixedly mounted in the middle of the second rotating shaft (15), a limit plate (17) is fixedly mounted on the top of the direction rod (18), and one end of the pull rod (16) away from the second rotating shaft (15) is connected to a side directly opposite to the swing platform (19).

7. The method for repairing thermal cracks in swing laser welding according to claim 1, characterized in that: The swing frequency in step 2 is specifically 90-150 Hz, and the swing amplitude in step 2 is a circular swing.

8. The method for repairing thermal cracks in swing laser welding according to claim 1, characterized in that: In the step 4, the protective gas is CO2.

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