Composite welding method and welding device for heterogeneous aluminum alloys

Abstract

The invention provides a hybrid welding method and device for heterogeneous aluminum alloys. The hybrid welding method comprises the following steps that S1, a hybrid welding heat source is arranged; s2, setting a laser angle theta1 and an angle theta2 of a welding wire; s3, setting a laser defocusing amount; s4, the distance between the welding wire and the laser is adjusted; s5, arc starting is conducted firstly, after arc starting succeeds, pulse laser is started, and the pulse laser is kept in a swing posture for welding; and S6, after welding is finished, laser light receiving and electric arc stopping are conducted. The composite welding method combining electric arc welding and pulse laser welding is adopted, laser and electric arc interact, the problem that the laser welding and the electric arc welding are used for independently welding different kinds of aluminum alloy is solved, welding hot cracks can be avoided, and the welding stability is improved on the premise that the welding quality and the welding speed are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a composite welding method and welding apparatus for dissimilar aluminum alloys. Background Technology

[0002] Die-cast aluminum is widely used in the automotive, telecommunications, electronics, and aerospace industries due to its high specific strength, good corrosion resistance, electrical and thermal conductivity, and casting and machining properties.

[0003] With the development of industries such as automobiles, the application of integral die-cast aluminum alloy parts in vehicle structural components is gradually increasing. Battery boxes, however, are mostly made of 5-series or 6-series wrought aluminum alloys. Among these, 6-series aluminum alloys, due to their superior mechanical properties, are used more extensively in battery packs than 5-series alloys. Currently, the connection technology between the vehicle body structure and the wrought aluminum alloy of the battery box has become crucial.

[0004] Among the existing battery pack connection technologies, friction stir welding, riveting, and laser welding are the most advanced. Friction stir welding and laser welding have the best mechanical properties, but they cannot meet the requirements for irregular welds and fillet welds.

[0005] Laser welding cannot completely avoid hydrogen porosity when welding die-cast aluminum, and it is prone to generating process porosity, resulting in performance degradation. The weld seam is relatively narrow during welding, which requires not only high positioning accuracy of the laser, but also high assembly accuracy.

[0006] Traditional arc welding, due to its insufficient energy density, causes significant thermal deformation of parts when welding aluminum alloys at the same welding depth as laser welding, and is prone to hot cracking, making it difficult to increase welding speed.

[0007] Due to differences in composition and thermophysical properties, die-cast aluminum and wrought aluminum are difficult to weld with deep penetration, and the aforementioned welding methods often fail to achieve the required weld quality. With the increasing demand for new energy vehicles, the development of a new welding process for dissimilar aluminum alloys is imperative. Summary of the Invention

[0008] The present invention aims to provide a composite welding method for dissimilar aluminum alloys to overcome the shortcomings of the prior art.

[0009] To solve the above-mentioned technical problems, the technical solution of the present invention is: a composite welding method for dissimilar aluminum alloys, employing a composite welding method combining pulsed laser welding and arc welding, comprising the following steps: S1. Set up a composite welding heat source, with the laser and the welding wire of the welding gun arranged along the welding direction of the workpiece, and the laser positioned in front of the welding gun. S2. Set the composite welding angle. First, set the laser angle. Based on the laser defocusing amount and the size of the laser head emitting the laser, set the angle θ1 between the laser and the workpiece surface. Then, set the angle θ2 between the welding wire and the workpiece surface. S3. Set the laser defocus amount. The laser can be positive or negative defocus, and the defocus amount is less than 10mm. Preferably, the defocus amount is less than 5mm, that is, within the range of -5mm to 5mm.

[0010] S4. Adjust the distance between the welding wire and the laser according to the arc welding process; S5. Welding: First, the welding torch ignites the arc. The arc welding parameters are set according to the workpiece material and thickness, including wire feed speed and arc power. The welding torch emits a high-power pulsed arc to break through the oxide layer on the aluminum alloy surface and form a molten pool. After successful arc ignition, the laser is activated and emits a pulsed laser to irradiate the molten pool. The duty cycle of the pulsed laser is 70%-80%. At the same time, the arc ignition power of the welding torch is reduced to the normal welding power within a set time. Then, the pulsed laser is injected into the molten pool in an oscillating posture to stir the molten pool until the welding is completed. S6. After welding, the laser beam is extinguished, the welding torch arc is extinguished, and the arc crater is filled.

[0011] Furthermore, in the above-mentioned composite welding method for dissimilar aluminum alloys, the angle θ1 between the laser and the workpiece surface is 80-85°.

[0012] Furthermore, in the above-mentioned composite welding method for dissimilar aluminum alloys, the angle θ2 between the welding wire and the workpiece surface is 60-70°.

[0013] Furthermore, in the above-mentioned composite welding method for dissimilar aluminum alloys, the distance between the welding wire and the laser is 0-4mm.

[0014] Furthermore, in the aforementioned composite welding method for dissimilar aluminum alloys, the high power during arc ignition is 1.3-1.6 times that of normal welding power, and after successful arc ignition, the arc ignition power of the welding torch decreases uniformly to the normal welding power within 0.3-0.6 seconds.

[0015] Furthermore, in the above-mentioned composite welding method for dissimilar aluminum alloys, the oscillation posture of the laser is controlled by the oscillation trajectory and oscillation frequency. The oscillation trajectory is sinusoidal, circular, figure-eight, or infinity, and the oscillation frequency is 150Hz-250Hz.

[0016] Furthermore, in the above-mentioned composite welding method for dissimilar aluminum alloys, a shielding gas is delivered through a welding torch before the arc is ignited, and the shielding gas is continuously supplied above the molten pool during the welding process, with a shielding gas supply flow rate of 20L / min-25L / min.

[0017] This invention also provides a composite welding device for dissimilar aluminum alloys, including a robot and a main control module, a laser welding module, and an arc welding module mounted on the robot. The robot drives the laser welding module and the arc welding module to move along the welding direction. The laser welding module includes a laser, and the laser head of the laser emits pulsed laser light that is focused onto the workpiece. The arc welding module includes a welding torch, and the welding torch outputs arc energy that acts on the workpiece. The main control module controls the laser welding module and the arc welding module to combine the arc with the pulsed laser to weld the workpiece, and during welding, the pulsed laser oscillates along a predetermined trajectory.

[0018] Furthermore, the aforementioned composite welding device for dissimilar aluminum alloys also includes an adjustment component. The laser welding module and the arc welding module are mounted on the robot via a fixed base. The laser welding module is located on one side of the fixed base, and the arc welding module is located on the opposite side of the fixed base. The adjustment component is located between the arc welding module and the fixed base and is used to adjust the distance between the welding wire of the welding gun and the laser.

[0019] Furthermore, in the aforementioned composite welding device for dissimilar aluminum alloys, the adjustment assembly includes an adjustment group one and an adjustment group two. The adjustment group one is mounted on a fixed base and is used to adjust the position of the welding torch in a first direction. The adjustment group two is located at the output end of the adjustment group one and is used to adjust the position of the welding torch in a second direction. The first direction is perpendicular to the second direction, and the second direction is parallel to the welding direction.

[0020] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention employs a composite welding method combining arc welding and pulsed laser welding. The plasma gas generated during laser welding stabilizes the arc, ensuring a stable and uninterrupted arc even at high speeds. Simultaneously, the arc welding absorbs the plasma generated during laser welding, reducing plasma consumption on the laser beam path. Furthermore, during laser welding, the arc first penetrates the oxide layer on the aluminum alloy surface, allowing the laser to directly strike the molten pool, reducing high reflection during aluminum alloy laser welding and further minimizing laser power loss. In addition, the arc welding widens the upper weld width, while the laser increases the weld depth at the bottom, ensuring both sufficient weld width and shear strength, while also providing higher tensile strength. The interaction between the laser and the arc eliminates the need for separate laser welding and arc welding of dissimilar aluminum alloys.

[0021] This invention uses pulsed lasers, which intermittently and repeatedly strike the molten pool during the welding process. This greatly reduces the heat-affected zone at the bottom of the weld, significantly reducing the heat input during welding and preventing welding hot cracks.

[0022] The composite welding method of the present invention can greatly reduce the retention of hydrogen pores during welding and effectively avoid the existence of process pores, thereby improving welding stability while ensuring welding quality and welding speed.

[0023] The composite welding device of the present invention has a simple structure, can automatically realize the composite welding of dissimilar aluminum alloys, and can adjust the welding posture in real time according to the workpiece to be welded, thus ensuring both welding speed and welding quality. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the composite welding device for dissimilar aluminum alloys according to the present invention; Figure 2 This is a schematic diagram of the welding position for the composite welding method of dissimilar aluminum alloys according to the present invention; Figure 3 This is a sequence diagram of the welding process for the composite welding method of dissimilar aluminum alloys of the present invention; Figure 4 This is a schematic diagram of the oscillation trajectory of the composite welding method for dissimilar aluminum alloys according to the present invention; Figure 5 This is a comparative schematic diagram of the weld seams in Embodiment 3 and Embodiment 2 of the present invention; Detailed Implementation

[0026] 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.

[0027] This invention provides a composite welding method for the lap joint of dissimilar aluminum alloys, namely die-cast aluminum and wrought aluminum. It utilizes a combination of arc welding and laser welding technology. After the arc is ignited, a pulsed laser is injected into the weld pool, and the pulsed laser oscillates according to a preset trajectory to achieve the welding of dissimilar aluminum alloys.

[0028] Example A composite welding method for dissimilar aluminum alloys, employing a combination of pulsed laser welding and arc welding, includes the following steps: S1. Set up a composite welding heat source, with the laser and welding torch wire positioned along the welding direction of the workpiece, and the laser positioned in front of the welding torch, such as... Figure 2 As shown; S2. Set the composite welding angle. First, set the laser angle. Based on the laser defocusing amount and the size of the laser head emitting the laser, set the angle θ1 between the laser and the workpiece surface. Figure 2 As shown, the angle θ1 is 80-85°. Since aluminum alloy is a highly reflective material, it reflects a lot of light. To prevent reflected light from entering the laser head and burning out the laser, a certain angle is set to ensure that reflected light does not enter the laser head lens. Then, the angle θ2 between the welding wire and the workpiece surface is set, as shown... Figure 2 As shown, the angle θ2 is 60-70°, and it is necessary to ensure that the welding torch does not touch the side wall of the workpiece.

[0029] S3. Set the laser defocus amount. The laser can be positively or negatively defocused. The laser defocus amount determines whether the laser energy density is concentrated. Positive defocus can obtain a better weld surface and less spatter, while negative defocus can obtain higher energy but more spatter. Therefore, the laser defocus amount needs to ensure both concentrated energy density and weld surface quality. Set the laser defocus amount to less than 10mm, i.e., within the range of -10mm to 10mm; preferably, the defocus amount is less than 5mm, i.e., within the range of -5mm to 5mm.

[0030] S4. Adjust the distance between the welding wire and the laser. The distance between the welding wire and the laser should be adjusted according to the arc welding process. The distance should be 0-4mm. S5, Welding, such as Figure 3 As shown, the welding torch first initiates the arc with a pulsed arc. The welding parameters, including wire feed speed and arc power, are set according to the workpiece material and thickness. The welding torch emits a high-power pulsed arc that penetrates the oxide layer on the aluminum alloy surface to form a molten pool. The high power at arc initiation is 1.3-1.6 times the normal welding power, and the arc initiation time is about 0.4 seconds. After successful arc initiation, the laser is activated and emits a pulsed laser to irradiate the molten pool. The duty cycle of the pulsed laser is 70%-80%. At the same time, the arc initiation power of the welding torch is uniformly reduced to the normal welding power within a set time, which is within 0.1-0.3 seconds.

[0031] Then, a pulsed laser is injected into the molten pool in an oscillating motion to stir the molten pool. The pulsed laser and the electric arc are welded synchronously until the welding is completed. The oscillating laser stirs the molten pool, allowing hydrogen pores that may have appeared in the die-cast aluminum during welding due to excessive hydrogen content to be expelled. Furthermore, the laser oscillation slightly reduces the energy density of the keyhole, resulting in a more uniform energy distribution and a lower keyhole depth-to-width ratio, transforming the keyhole from a deep, narrow type to a wide, shallow type. The stirring also enhances the fluidity of the molten pool, thus reducing laser-induced porosity. Simultaneously, the combined action of the oscillating laser and the pulsed laser on the molten pool intensifies the stirring effect, allowing the wrought aluminum and the die-cast aluminum matrix to fully fuse, achieving homogenization of the molten pool composition and improving weld quality.

[0032] The laser's oscillation attitude is controlled by its oscillation trajectory and frequency. The oscillation trajectory can be sinusoidal, circular, figure-eight shaped, or infinity-shaped. The relationship between each oscillation trajectory and the welding direction is as follows: Figure 4 As shown, the figure-eight shape has a wider weld width, while the ∞ shape has a deeper weld depth. Different laser oscillation methods are matched with different welding materials, and the oscillation frequency is 150Hz-250Hz.

[0033] S6. After welding, the laser beam is extinguished, the welding torch arc is extinguished, and the arc crater is filled.

[0034] In addition, before the electric arc is ignited, a shielding gas, which is argon, is delivered through the welding torch and is continuously supplied above the molten pool during the welding process. The shielding gas supply flow rate is 20L / min-25L / min.

[0035] During welding, igniting the electric arc in advance allows the laser to penetrate the molten pool upon activation, minimizing the formation of dense porosity and improving welding stability. If the laser arc is delayed or activated synchronously with the electric arc, the plasma emitted by the laser will create dense porosity at the arc initiation point.

[0036] Furthermore, aluminum alloys are highly susceptible to hot cracking during welding. Using a continuous laser would result in excessive heat input from the laser and arc, increasing the probability of hot crack formation. This invention employs a pulsed laser, intermittently and repeatedly striking the molten pool during welding. This significantly reduces the heat-affected zone at the bottom of the weld, substantially decreasing the heat input and preventing hot cracking.

[0037] This invention employs a composite welding method combining arc welding and pulsed laser welding. The plasma gas generated during laser welding stabilizes the arc, ensuring a stable and uninterrupted arc even at high speeds. Simultaneously, the arc welding absorbs the plasma generated during laser welding, reducing plasma consumption on the laser beam path. Furthermore, during laser welding, the arc first penetrates the oxide layer on the aluminum alloy surface, allowing the laser to directly strike the molten pool, reducing high reflection during aluminum alloy laser welding and further minimizing laser power loss.

[0038] This invention widens the upper weld width through arc welding and increases the bottom penetration depth of the weld through laser, ensuring both sufficient penetration depth and adequate weld width. It also provides higher tensile strength while maintaining the weld's shear resistance.

[0039] In Example 1, the two workpieces to be welded are made of die-cast aluminum and wrought aluminum, respectively. The two workpieces are lap-welded, and the welding direction is along the lap joint.

[0040] Before welding, remove the oxide film from the target location of the workpiece to be welded, then clean the target location of the workpiece to be welded with acetone and ethanol in sequence, and fix the workpiece to be welded on the welding station after drying.

[0041] The welding process employs a composite welding method combining pulsed laser and electric arc, specifically including the following steps: S1. Set up a composite welding heat source, with the laser and the welding wire of the welding gun arranged along the welding direction of the workpiece, and the laser positioned in front of the welding gun. S2. Set the composite welding angle. First, set the laser angle. Based on the laser defocusing amount and the size of the laser head emitting the laser, set the angle θ1 between the laser and the workpiece surface. This angle θ1 is 85°. Then, set the angle θ2 between the welding wire and the workpiece surface. This angle θ2 is 60°. It is necessary to ensure that the welding torch does not touch the side wall of the workpiece.

[0042] S3. Set the laser defocus amount. The laser can be either positive or negative defocus, and the defocus amount must be less than 10mm, i.e., within the range of -10mm to 10mm. S4. Adjust the distance between the welding wire and the laser. Adjust the distance between the welding wire and the laser according to the arc welding process. The distance should be 4mm. S5. Welding: First, the welding torch ignites the arc. The welding torch emits a high-power pulsed arc that breaks through the oxide layer on the surface of the aluminum alloy to form a molten pool. The high power of the arc ignition is 1.3 times the normal welding power, and the arc ignition time is about 0.4 seconds. After successful arc ignition, the laser is activated and emits a pulsed laser to irradiate the molten pool. The duty cycle of the pulsed laser is 70%. At the same time, the arc ignition power of the welding torch is uniformly reduced to the normal welding power within 0.3 seconds. Then, the pulsed laser is injected into the molten pool in an oscillating posture to stir the molten pool. The pulsed laser and the electric arc are welded synchronously until the welding is completed. The oscillating posture of the laser is controlled by the oscillating trajectory and the oscillating frequency. The oscillating trajectory is a sine wave, and the oscillating frequency is 250Hz.

[0043] S6. After welding, the laser beam is extinguished, the welding torch arc is extinguished, and the arc crater is filled.

[0044] In addition, before the arc is ignited, a shielding gas, which is argon, is delivered through the welding torch and is continuously supplied above the molten pool during the welding process. The shielding gas supply flow rate is 22L / min.

[0045] In Example 2, the two workpieces to be welded are made of die-cast aluminum and wrought aluminum, respectively. One workpiece is a 125mm*45mm*8mm thick die-cast aluminum plate, and the other is a 6061 wrought aluminum plate of the same specifications. The two workpieces are overlapped and welded, and the welding direction is along the overlap interface.

[0046] Before welding, the workpiece must be cleaned to remove the oxide film on its surface. Then, it should be washed and dried. Finally, the cleaned workpiece should be fixed at the welding station. When placing it, it should be arranged according to the lap weld method, with an overlap of 33mm (meeting the requirement of 3 times the thickness of the test plate). The center lines of the two test plates in the width direction should be aligned, with no horizontal offset. The mating surfaces of the test plates should be in close contact, with local gaps ≤0.1mm and no warping.

[0047] The welding process employs a composite welding method combining pulsed laser and electric arc, specifically including the following steps: S1. Set up a composite welding heat source, with the laser and the welding wire of the welding gun arranged along the welding direction of the workpiece, and the laser positioned in front of the welding gun. S2. Set the composite welding angle. First, set the laser angle. Based on the laser defocusing amount and the size of the laser head emitting the laser, set the angle θ1 between the laser and the workpiece surface. This angle θ1 is 80°. Then, set the angle θ2 between the welding wire and the workpiece surface. This angle θ2 is 70°. It is necessary to ensure that the welding torch does not touch the side wall of the workpiece.

[0048] S3. Set the laser defocus amount. The laser can be either positive or negative defocus. The defocus amount should be less than 5mm, i.e., within the range of -5mm to 5mm.

[0049] S4. Adjust the distance between the welding wire and the laser. Adjust the distance between the welding wire and the laser according to the arc welding process. The distance is 1mm. By adjusting the distance between the welding wire and the laser, ensure that the laser can penetrate into the molten pool. S5. Welding: First, the welding torch ignites the arc. The arc welding parameters are set according to the workpiece material and thickness. The welding parameters include wire feed speed, arc power, etc. In this embodiment, the welding current is 145A, the welding voltage is 18.5V, and the wire feed speed is 6.4m / min. The welding torch emits a high-power pulsed arc to break through the oxide layer on the surface of the aluminum alloy to form a molten pool. The high power at the arc ignition is 1.46 times the normal welding power, and the arc ignition time is about 0.4S. After successful arc ignition, the laser is activated to emit pulsed laser light to irradiate the molten pool. The duty cycle of the pulsed laser is 75%. At the same time, the arc ignition power of the welding torch is uniformly reduced to the normal welding power within 0.2S.

[0050] Then, the pulsed laser is injected into the molten pool in an oscillating manner to stir the molten pool. The pulsed laser and the electric arc are welded synchronously at a welding speed of 30 mm / s until the welding is completed. The oscillation posture of the laser is controlled by the oscillation trajectory and the oscillation frequency. The oscillation trajectory is circular and the oscillation frequency is 200Hz.

[0051] S6. After welding, the laser is extinguished, the welding torch arc is extinguished, and the arc power is reduced to 0.46 times the normal welding power. The arc extinguishing time is the same as the arc ignition time, which is about 0.4 seconds, to fill the arc extinguishing crater.

[0052] In addition, before the arc is ignited, a shielding gas, which is argon, is delivered through the welding torch and is continuously supplied above the molten pool during the welding process. The shielding gas supply flow rate is 20L / min.

[0053] In Example 3, based on Example 2, the laser is changed to a continuous laser without oscillation. For example... Figure 5 As shown, where Figure 5 a is a schematic diagram of the weld in Example 3. Figure 5 Figure b shows a schematic diagram of the weld in Example 32. The comparison shows that without laser oscillation, circular hydrogen pores cannot effectively escape from the weld, and there are still many irregularly shaped process-type pores. Furthermore, because the laser is not oscillating, the laser energy is unstable under the influence of the electric arc, resulting in unstable penetration depth. With laser oscillation, hydrogen pores can be effectively expelled from the weld, and due to the uniform dispersion of laser energy density, the formation of process-type pores can be effectively avoided, resulting in a more uniform penetration depth.

[0054] In summary, the composite welding method of the present invention can greatly reduce the retention of hydrogen pores during welding and effectively avoid the existence of process-related pores. This process improves welding stability while ensuring welding quality and welding speed.

[0055] like Figure 1 , 2As shown, the present invention also provides a composite welding device for dissimilar aluminum alloys, including a robot and a main control module, a laser welding module, and an arc welding module mounted on the robot. The robot drives the laser welding module and the arc welding module to move along the welding direction. The laser welding module includes a laser 1, the laser head of the laser 1 emits pulsed laser light that is focused on the workpiece for laser welding. The arc welding module includes a welding torch 2, the welding torch 2 outputs arc energy that acts on the workpiece for arc welding. The main control module controls the laser welding module and the arc welding module to combine the arc with the pulsed laser to weld the workpiece, and during welding, the pulsed laser is made to oscillate along a predetermined trajectory.

[0056] The aforementioned composite welding device for dissimilar aluminum alloys also includes an adjustment component 3. The laser 1 and the welding torch 2 are mounted on the robot via a fixed base 4. The laser 1 is located on one side of the fixed base 4, and the welding torch is located on the other side of the fixed base 4. The adjustment component 3 is located between the arc welding module and the fixed base 4 and is used to adjust the distance between the welding wire of the welding torch 2 and the laser.

[0057] The adjustment assembly 3 includes an adjustment group one 31 and an adjustment group two 32. The adjustment group one 31 is mounted on the fixed base 4 and is used to adjust the position of the welding torch 2 in a first direction. The adjustment group two 32 is located at the output end of the adjustment group one 31 and is used to adjust the position of the welding torch 2 in a second direction. The first direction is perpendicular to the second direction, and the second direction is parallel to the welding direction. The welding torch 2 is mounted on the output end of the adjustment group two 32 via a welding torch holder 5. By adjusting the relative position of the welding torch and the laser through the adjustment assembly, the laser and the welding wire are kept in a straight line in the welding direction, allowing the laser to accurately enter the molten pool. In this embodiment, the adjustment groups one 31 and the adjustment group two 32 have the same structure, both being manual displacement stages composed of lead screws, slide rails, etc., with adjustment knobs on them, making installation simple and adjustment convenient.

[0058] Before welding, the robot automatically adjusts the laser's incident angle according to the material of the workpiece to be welded, and the relative position of the welding torch 2 and the laser can be adjusted via the adjustment component 3. During welding, an electric arc is first used to ignite the weld, using a high-power pulsed arc to break through the oxide layer on the aluminum alloy surface. After successful arc ignition, the welding machine sends a feedback signal to the robot, which then transmits the signal to the laser 1. The laser head emits pulsed laser light, which is now irradiating the molten pool. Simultaneously, after arc ignition, its power output gradually decreases from the high power at arc ignition to the normal welding power through a gradual process. During welding, the relative position of the galvanometers inside the laser head is controlled to make the laser spot oscillate along a predetermined trajectory. The oscillating laser continuously stirs the molten pool, achieving an oscillation effect. At the end of welding, the laser is directly withdrawn, and then the electric arc is used to close the arc and fill the crater.

[0059] The composite welding device of the present invention has a simple structure, can automatically realize the composite welding of dissimilar aluminum alloys, and can adjust the welding posture in real time according to the workpiece to be welded, thus ensuring both welding speed and welding quality.

[0060] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0061] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A composite welding method for dissimilar aluminum alloys, characterized in that: A hybrid welding method combining pulsed laser welding and arc welding includes the following steps: S1. Set up a composite welding heat source, with the laser and the welding wire of the welding gun arranged along the welding direction of the workpiece, and the laser positioned in front of the welding gun. S2. Set the composite welding angle. First, set the laser angle. Based on the laser defocusing amount and the size of the laser head emitting the laser, set the angle θ1 between the laser and the workpiece surface. Then, set the angle θ2 between the welding wire and the workpiece surface. S3. Set the laser defocus amount. The laser can be either positive or negative defocus, and the defocus amount must be less than 10mm. S4. Adjust the distance between the welding wire and the laser according to the arc welding process; S5. Welding: First, the welding torch ignites the arc. The welding torch emits a high-power pulsed arc that breaks through the oxide layer on the surface of the aluminum alloy to form a molten pool. After successful arc ignition, the laser is activated and emits a pulsed laser to irradiate the molten pool. The duty cycle of the pulsed laser is 70%-80%. At the same time, the arc ignition power of the welding torch is reduced to the normal welding power within a set time. Then, the pulsed laser is injected into the molten pool in an oscillating posture to stir the molten pool until the welding is completed. S6. After welding, the laser beam is extinguished, the welding torch arc is extinguished, and the arc crater is filled.

2. The composite welding method for dissimilar aluminum alloys according to claim 1, characterized in that: The angle θ1 between the laser and the workpiece surface is 80-85°.

3. The composite welding method for dissimilar aluminum alloys according to claim 2, characterized in that: The angle θ2 between the welding wire and the workpiece surface is 60-70°.

4. The composite welding method for dissimilar aluminum alloys according to claim 1, characterized in that: The distance between the welding wire and the laser is 0-4mm.

5. The composite welding method for dissimilar aluminum alloys according to claim 1, characterized in that: The high power during arc ignition is 1.3-1.6 times that of normal welding power, and after successful arc ignition, the arc ignition power of the welding torch decreases uniformly to the normal welding power within 0.3-0.6 seconds.

6. The composite welding method for dissimilar aluminum alloys according to claim 1, characterized in that: The oscillation posture of the laser is controlled by the oscillation trajectory and oscillation frequency. The oscillation trajectory is a sine wave, a circle, a figure-eight shape, or an infinity shape, and the oscillation frequency is 150Hz-250Hz.

7. The composite welding method for dissimilar aluminum alloys according to claim 1, characterized in that: Before the electric arc is ignited, shielding gas is delivered through the welding torch and is continuously supplied above the molten pool during the welding process. The shielding gas supply flow rate is 20L / min-25L / min.

8. A welding apparatus for implementing the composite welding method of dissimilar aluminum alloys as described in any one of claims 1-7, characterized in that: The system includes a robot and a main control module, a laser welding module, and an arc welding module mounted on the robot. The robot drives the laser welding module and the arc welding module to move along the welding direction. The laser welding module includes a laser, whose laser head emits pulsed laser light that is focused onto the workpiece. The arc welding module includes a welding torch, which outputs arc energy that acts on the workpiece. The main control module controls the laser welding module and the arc welding module to combine the arc with the pulsed laser to weld the workpiece, and during welding, the pulsed laser oscillates along a predetermined trajectory.

9. The composite welding apparatus for dissimilar aluminum alloys according to claim 8, characterized in that: It also includes an adjustment component. The laser welding module and the arc welding module are mounted on the robot via a fixed base. The laser welding module is located on one side of the fixed base, and the arc welding module is located on the other side of the fixed base. The adjustment component is located between the arc welding module and the fixed base and is used to adjust the distance between the welding wire of the welding gun and the laser.

10. The composite welding apparatus for dissimilar aluminum alloys according to claim 9, characterized in that: The adjustment assembly includes an adjustment group one and an adjustment group two. The adjustment group one is mounted on a fixed base and is used to adjust the position of the welding torch in a first direction. The adjustment group two is located at the output end of the adjustment group one and is used to adjust the position of the welding torch in a second direction. The first direction is perpendicular to the second direction, and the second direction is parallel to the welding direction.

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