Laser-arc hybrid welding equipment and welding method for aluminum alloy

Abstract

The present invention discloses a laser-arc hybrid welding device and welding method for aluminum alloys. The device comprises a laser generating device, a non-melting inert gas shielded arc welding gun, and a metal active gas shielded welding gun. The non-melting inert gas shielded arc welding gun adopts a direct current positive connection, while the metal active gas shielded welding gun adopts a direct current reverse connection. The angle between the non-melting inert gas shielded arc welding gun and the laser beam is 25° to 45°. Along the welding direction, the non-melting inert gas shielded arc welding gun is in front, and the metal active gas shielded welding gun is in the back. The laser beam is a variable power square wave pulse laser beam, and the power ratio of high-power laser pulses to low-power laser pulses is 2:1. This design improves energy utilization, increases the single-shot penetration depth of the weld and the welding speed, and simultaneously reduces workpiece assembly requirements, improves weld quality, and improves weld formation.

Description

Technical Field

[0001] The present invention relates to the field of welding processing, in particular to a laser-arc composite welding device and a welding method for aluminum alloy. Background Art

[0002] Aluminum alloys are the most widely used metal structural materials in industry, finding extensive application in aviation, aerospace, automotive, machinery manufacturing, shipbuilding, and the chemical industry. With the rapid development of science, technology, and the industrial economy in recent years, the demand for welded structural components has increased, leading to in-depth research on the weldability of aluminum alloys. The widespread use of aluminum alloys has promoted the development of aluminum alloy welding technology, while the development of welding technology has also expanded the application areas of aluminum alloys. Therefore, aluminum alloy welding technology has become a hot topic of research.

[0003] There are several major difficulties in welding aluminum alloys: an aluminum oxide film with a high melting point is easily formed on the surface of the weld joint, requiring a high-power density welding process. In addition, the high thermal conductivity and linear expansion coefficient make it easy to produce defects such as pores and thermal cracks. Aluminum alloys are generally welded using non-metallic inert gas arc welding (TIG) and metal active gas arc welding (MIG). However, the main problem during the welding process is the large welding heat input, which leads to large welding deformation, slow welding speed, and low welding efficiency. In addition, during the high temperature conditions of the welding process, hydrogen gas dissolves in the molten pool metal. During solidification and phase change, the solubility of the gas decreases and there is no time to escape, resulting in a large number of pores in the weld. Laser welding has the characteristics of high power density, low welding heat input, small welding heat-affected zone, and small welding deformation, making it particularly important in the field of aluminum alloy welding. However, there are still bottlenecks in the laser welding of aluminum alloys. For example, the high initial reflectivity of aluminum alloy to the laser beam and its own high thermal conductivity make the aluminum alloy have low absorption rate of laser before melting, making it difficult to induce "pinholes"; the low ionization energy of aluminum makes it easy for photo-induced plasma to process and diffuse during welding, resulting in poor welding stability; pores and thermal cracks are easily generated during the laser welding of aluminum alloys; and the burning of alloying elements during welding reduces the mechanical properties of aluminum alloy welded joints. Laser-arc hybrid welding utilizes the deep melting effect of laser and has the advantages of variable polarity plasma welding of aluminum alloys while improving welding efficiency, reducing welding current, and reducing heat input, thereby improving the softening problem of high-strength aluminum alloy welded joints.

[0004] However, the laser arc hybrid welding method has the following disadvantages: 1) It has a weak ability to penetrate the welding plate; it is easy to cause undercuts and weld toe cracks when opening a groove; when the groove is not opened, the welding current needs to be increased, which will lead to high heat input and reduced joint strength; 2) High-strength aluminum alloy welded joints are severely softened, the non-compressed arc is more divergent, and the welding heat input is large; 3) The back of the weld is poorly formed, often with incomplete welding and large excess height fluctuations. 4) The tendency to slag inclusion, porosity and cracks is more serious. The above problems restrict industrial production and application. Therefore, in view of the shortcomings of the above-mentioned laser-arc hybrid welding method, it is necessary to provide a more economical and efficient welding method. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a laser-arc hybrid welding device for aluminum alloys.

[0006] The present invention also proposes a welding method for laser-arc hybrid welding equipment applied to aluminum alloys.

[0007] According to the first aspect of the present invention, a laser-arc hybrid welding device for aluminum alloy includes a laser generating device, a non-melting-pole inert gas shielded arc welding gun and a melting-pole active gas shielded welding gun. The non-melting-pole inert gas shielded arc welding gun adopts DC positive connection, and the melting-pole active gas shielded welding gun adopts DC reverse connection. The laser beam emitted by the laser generating device is arranged vertically downward. The non-melting-pole inert gas shielded arc welding gun and the melting-pole active gas shielded welding gun are respectively located on the front and rear sides of the laser beam, and the angle between them and the laser beam is 25° to 45°. Along the welding direction, the non-melting-pole inert gas shielded arc welding gun is in front and the melting-pole active gas shielded welding gun is in the back; the laser beam is a variable-power square wave pulse laser beam, and the power ratio of high-power laser pulse and low-power laser pulse is 2:1.

[0008] Based on the above design, the laser-arc hybrid welding equipment for aluminum alloy provided in this application has at least the following beneficial effects:

[0009] Welding is performed by alternating between a non-melting inert gas shielded arc welding gun and a laser composite heat source, and a non-melting inert gas shielded arc welding gun-laser composite heat source. Each composite heat source combines the advantages of the two independent heat sources, laser and arc, and avoids the disadvantages of both to a great extent, improving energy utilization, increasing the weld penetration depth and welding speed; at the same time, it reduces workpiece assembly requirements, improves weld quality, and improves weld formation.

[0010] According to some embodiments of the present invention, a current sensor and a signal controller are further included, wherein the current sensor is used to monitor the current signal of the ignition arc of the non-melting electrode inert gas shielded arc welding gun and the melt-forming electrode active gas shielded welding gun, and the signal controller controls the switching of the high-power pulse and the low-power pulse of the laser beam through the current signal detected by the current sensor to be consistent with the ignition arc of the non-melting electrode inert gas shielded arc welding gun and the melt-forming electrode active gas shielded welding gun.

[0011] According to some embodiments of the present invention, an insulated gate bipolar transistor switch is further included, and the insulated gate bipolar transistor switch is used to alternately control the power on and off of the non-melting electrode inert gas shielded arc welding gun and the metal active gas shielded welding gun.

[0012] According to some embodiments of the present invention, the laser beam is a fiber laser or a YAG laser, the focal length of the laser beam is 150 mm-500 mm, and the focal spot diameter of the laser beam is 0.2 mm-0.6 mm.

[0013] According to some embodiments of the present invention, the vertical distance between the tip of the tungsten electrode of the non-melting electrode inert gas shielded arc welding gun and the surface of the workpiece to be welded is 1.5mm-5mm, and the horizontal distance between the tip and the scanning center of the laser beam is 2mm-3mm. The horizontal distance between the melting electrode wire of the melting electrode active gas shielded welding gun and the scanning center of the laser beam is 1mm-2mm.

[0014] According to some embodiments of the present invention, the visible arc length of the MIG / MAG welding torch is maintained at 4-8 mm.

[0015] According to another embodiment of the present invention, a welding method of aluminum alloy using a laser-arc hybrid welding device includes the following steps:

[0016] S1: The non-metallic inert gas shielded arc welding torch and the metal active gas shielded arc welding torch ignite arcs alternately, and simultaneously act on the butt joint of the workpieces to be welded with the laser beam to form a eutectic pool;

[0017] S2: while the non-melting inert gas shielded arc welding gun is igniting the arc, a low-power laser pulse is triggered, and the focus of the laser beam is adjusted to the surface of the workpiece to be welded, the non-melting inert gas shielded arc welding gun and the low-power laser pulse form a composite heat source; the arc ignition time of the non-melting inert gas shielded arc welding gun is 5-10ms; the energy ratio of the non-melting inert gas shielded arc welding gun to the low-power laser pulse during the welding process is 1.2-1.6;

[0018] S3: While the arc is ignited by the MIG welding gun, a high-power laser pulse is triggered, and the focus of the laser beam is adjusted to a position 1 / 3-1 / 2 of the molten pool depth from the surface of the workpiece to be welded. The MIG welding gun and the high-power laser pulse form a composite heat source; the arc ignition time of the MIG welding gun is 15-25ms; the energy ratio of the MIG welding gun to the high-power laser pulse during the welding process is 1.2-1.6.

[0019] Based on the above design, the laser-arc hybrid welding method for aluminum alloy provided in this application has at least the following beneficial effects:

[0020] By alternately igniting the arc with a non-melting inert gas shielded arc welding torch and a non-melting inert gas shielded arc welding torch, electromagnetic interference when the two arcs are generated at the same time can be avoided. Under reasonable welding specifications, the complementary advantages of stable TIG welding arc and high MIG welding efficiency can be achieved; the parameter adjustment range is wide, and by adjusting parameters such as current, voltage, switching frequency, electrode spacing, and position relationship between electrodes, the welding of aluminum alloy specimens of different thicknesses can be completed.

[0021] According to some embodiments of the present invention, before welding in step S1, the workpiece to be welded is preheated to allow the workpiece to reach a set temperature.

[0022] According to some embodiments of the present invention, when the arcs are alternately ignited in step S1 , the focusing mirror of the laser generating device moves in a vertical direction to adjust the focus point of the laser beam.

[0023] According to some embodiments of the present invention, after welding in step S3, the temperature of the welding area is detected. When the welding area drops to the set preheating temperature at room temperature, high-frequency heating is used to control the temperature to drop to room temperature at a rate of 2-6°C / min.

[0024] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0026] Figure 1 The figure is a schematic structural diagram of a laser-arc hybrid welding device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0028] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, inside, outside, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0029] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0030] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, assembling, and matching should be understood in a broad sense. Technical personnel in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0031] Reference Figure 1 , a laser-arc hybrid welding equipment for aluminum alloy, which includes a laser generating device 1, a non-melting inert gas shielded arc welding gun 2 and a melting electrode active gas shielded welding gun 3, the non-melting inert gas shielded arc welding gun 2 adopts DC positive connection, and the melting electrode active gas shielded welding gun 3 adopts DC reverse connection, the laser beam emitted by the laser generating device 1 is arranged vertically downward, the non-melting inert gas shielded arc welding gun 2 and the melting electrode active gas shielded welding gun 3 are respectively located in front and rear sides of the laser beam, and the angle between them and the laser beam is 25° to 45°, along the welding direction, the non-melting inert gas shielded arc welding gun 2 is in front, and the melting electrode active gas shielded welding gun 3 is in the back; the laser beam is a variable power square wave pulse laser beam, and the power ratio of high power laser pulse and low power laser pulse is 2:1.

[0032] The non-melting electrode inert gas arc welding torch 2 uses a direct current positive connection to facilitate cathode electron emission, thereby reducing tungsten electrode burnout and improving current carrying capacity. The metal active gas welding torch 3 uses a direct current reverse connection to clean the oxide film on the aluminum alloy surface, while maintaining a high wire melting efficiency by connecting the metal active gas welding torch to the positive electrode. The welding process alternates between a direct current positive connection non-melting electrode inert gas arc welding-laser composite heat source and a reverse current reverse connection metal active gas welding-laser composite heat source, further facilitating the alternating current arc. Compared to using only one electrode to alternately supply positive and negative currents for arc initiation, the design requirements for the power supply are lower, electrode burnout is reduced, and the service life of the electrode is increased.

[0033] In this embodiment, a current sensor and a signal controller are also included. The current sensor is used to monitor the current signal of the ignition arc of the non-melting electrode inert gas shielded arc welding gun 2 and the melt-forming active gas shielded welding gun 3. The signal controller controls the switching of the high-power pulse and the low-power pulse of the laser beam through the current signal detected by the current sensor to be consistent with the ignition arc of the non-melting electrode inert gas shielded arc welding gun 2 and the melt-forming active gas shielded welding gun 3.

[0034] In this embodiment, an insulated gate bipolar transistor switch is further included, and the insulated gate bipolar transistor switch is used to alternately control the power on and off of the non-melting electrode inert gas shielded arc welding torch 2 and the melt-forming electrode active gas shielded welding torch 3.

[0035] In this embodiment, the laser beam is a fiber laser or a YAG laser, the focal length of the laser beam is 150 mm to 500 mm, and the focal spot diameter of the laser beam is 0.2 mm to 0.6 mm.

[0036] In this embodiment, the vertical distance between the tip of the tungsten electrode of the non-melting electrode inert gas shielded arc welding gun 2 and the surface of the workpiece to be welded is 1.5 mm to 5 mm, and the horizontal distance between the tip and the scanning center of the laser beam is 2 mm to 3 mm. The horizontal distance between the melting electrode wire of the melting electrode active gas shielded welding gun 3 and the scanning center of the laser beam is 1 mm to 2 mm.

[0037] In this embodiment, the visible arc length of the MIG welding torch 3 is maintained at 4-8 mm. The voltage of the MIG welding torch 3 is adjusted according to the type and size of the welding wire used so that the molten droplet transfer of the welding wire is in the form of constant jet transfer. The visible arc length of the arc refers to the distance between the front end of the welding wire and the base material. Only when the visible arc length is within the range of 4-8 mm does the arc voltage change less with the visible arc length of the arc. This region is also the constant jet zone where the molten droplet transfer is in the form of constant jet transfer. The constant jet transfer welding current value remains essentially unchanged, which controls the frequency of molten droplet transfer, the mode of molten droplet transfer, and the discontinuity of the molten droplet volume during the welding process, maintains the stability of the molten pool state, reduces the welding line energy and overheating of the weld fusion zone, prevents unidirectional crystallization in the molten pool, and reduces the tendency of pores and cracks.

[0038] Welding is performed by alternating between a non-melting inert gas shielded arc welding gun and a laser composite heat source, and a non-melting inert gas shielded arc welding gun-laser composite heat source. Each composite heat source combines the advantages of the two independent heat sources, laser and arc, and avoids the disadvantages of both to a great extent, improving energy utilization, increasing the weld penetration depth and welding speed; at the same time, it reduces workpiece assembly requirements, improves weld quality, and improves weld formation.

[0039] A welding method of aluminum alloy using laser-arc hybrid welding equipment, comprising the following steps:

[0040] S1: The non-metallic inert gas shielded arc welding torch 2 and the metal active gas shielded arc welding torch 3 ignite arcs alternately, and simultaneously act on the butt joint of the workpieces to be welded with the laser beam to form a eutectic pool;

[0041] S2: while the non-combustible inert gas shielded arc welding gun 2 ignites the arc, a low-power laser pulse is triggered, and the focus of the laser beam is adjusted to the surface of the workpiece to be welded. The non-combustible inert gas shielded arc welding gun 2 and the low-power laser pulse form a composite heat source; the arc ignition time of the non-combustible inert gas shielded arc welding gun 2 is 5-10ms; the energy ratio of the non-combustible inert gas shielded arc welding gun 2 to the low-power laser pulse during the welding process is 1.2-1.6;

[0042] S3: While the arc is ignited by the MIG welding gun 3, a high-power laser pulse is triggered, and the focus of the laser beam is adjusted to a position 1 / 3-1 / 2 of the molten pool depth from the surface of the workpiece to be welded. The MIG welding gun 3 and the high-power laser pulse form a composite heat source; the arc ignition time of the MIG welding gun 3 is 15-25ms; the energy ratio of the MIG welding gun 3 to the high-power laser pulse during the welding process is 1.2-1.6.

[0043] In this embodiment, before welding in step S1, the workpiece to be welded is preheated to reach a set temperature. The set preheating temperature is determined according to the aluminum alloy type of the workpiece to be welded.

[0044] In this embodiment, when the arc is alternately ignited in step S1, the focusing mirror of the laser generating device moves in the vertical direction to adjust the focus point of the laser beam.

[0045] In this embodiment, after the welding in step S3, the temperature of the welding area is detected. When the welding area drops to the set preheating temperature at room temperature, high-frequency heating is used to control the temperature to drop to room temperature at a rate of 2-6°C / min. After the welding area drops to a certain temperature (the set preheating temperature), if the temperature and speed during cooling are not controlled, when the temperature drops too quickly, the liquid aluminum alloy sheet will suddenly shrink, and cracks are likely to appear on the surface, and faults are also likely to appear inside. By controlling the temperature to slowly drop after welding by high-frequency heating, cracks on the surface and stratification inside due to excessive cooling can be avoided, further improving the tightness of the weld between the parts to be welded.

[0046] During the welding process, as the welding process switches between non-metallic inert gas shielded arc welding and metal active gas shielded arc welding, the focus of the laser beam is adjusted between the surface of the workpiece to be welded and a position 1 / 3-1 / 2 of the molten pool depth from the surface of the workpiece to be welded. This can promote the flow of the molten pool and increase the heat transfer in the thickness direction of the workpiece, which can effectively increase the welding penetration depth and promote the uniform distribution of alloying elements in the molten pool, thereby improving the composition uniformity of the weld joint. When the focus of the laser beam is on the surface of the workpiece to be welded (at the zero defocus position), the laser beam spot diameter is the smallest and the laser power density is the largest, which is more conducive to the rapid formation of the molten pool and increased deep penetration. When the beam focus position moves from the workpiece surface to the middle area of ​​the molten pool thickness, although the energy of the laser beam is reduced, its divergence gradually decreases, which is more conducive to the stability of the keyhole and the improvement of welding quality. Through a large number of experiments, it was found that when the focus of the laser beam is on the surface of the workpiece to be welded, in order to prevent the metal from overheating, it should be combined with a low-power laser pulse and a TIG arc with lower power in the arc heat source; when the focus of the laser beam moves downward, the laser power density decreases. In order to increase the heat input of the welding wire, improve the melting speed and welding speed, and obtain better welding quality, it should be combined with a high-power pulse laser and a MIG arc with higher power in the arc heat source.

[0047] Example 1

[0048] In a first embodiment of the present invention, a method for welding 6061 aluminum alloy is provided, wherein the welding wire is ER4043 welding wire with a diameter of 1.4 mm.

[0049] The power of high-power laser pulse is 800-1000w, the power of low-power laser pulse is 400-500w, the output current of non-melting inert gas shielded arc welding gun is 100-200A, the arc starting time each time is 5-10ms, the current of non-melting inert gas shielded arc welding gun is, the voltage is 25-27V, and the arc action time each time is 15-25ms.

[0050] According to the aluminum alloy model, the heat input value Q per unit plate thickness is controlled. The heat input value Q per unit plate thickness is 2500-10000 (J / cm 2 ).

[0051] The present invention adopts a non-melting inert gas shielded arc welding torch and a non-melting inert gas shielded arc welding torch to alternately ignite the arc, which can avoid electromagnetic interference when the two arcs are generated at the same time. Under reasonable welding specifications, the complementary advantages of TIG welding arc stability and MIG welding high efficiency can be achieved; the parameter adjustment range is wide, and by adjusting parameters such as current, voltage, switching frequency, electrode spacing, and position relationship between electrodes, the welding of aluminum alloy specimens with different thicknesses can be completed.

[0052] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A laser-arc hybrid welding device for aluminum alloy, characterized in that: The invention comprises a laser generating device (1), a non-melting electrode inert gas shielded arc welding gun (2) and a melting electrode active gas shielded welding gun (3), wherein the non-melting electrode inert gas shielded arc welding gun (2) adopts a direct current positive connection, and the melting electrode active gas shielded welding gun (3) adopts a direct current reverse connection, the laser beam emitted by the laser generating device (1) is arranged vertically downward, the non-melting electrode inert gas shielded arc welding gun (2) and the melting electrode active gas shielded welding gun (3) are respectively located at the front and rear sides of the laser beam, and the angle between them and the laser beam is 25° to 45°, and along the welding direction, the non-melting electrode inert gas shielded arc welding gun (2) is in front and the melting electrode active gas shielded welding gun (3) is in the rear; the laser beam is a variable power square wave pulse laser beam, and the power ratio of the high power laser pulse and the low power laser pulse is 2:1; the visible arc length of the melting electrode active gas shielded welding gun (3) is maintained at 4-8 mm; It also includes a current sensor and a signal controller, wherein the current sensor is used to monitor the current signal of the ignition arc of the non-melting electrode inert gas shielded arc welding gun (2) and the melt-active gas shielded welding gun (3), and the signal controller controls the switching of the high-power pulse and the low-power pulse of the laser beam through the current signal detected by the current sensor to be consistent with the ignition arc of the non-melting electrode inert gas shielded arc welding gun (2) and the melt-active gas shielded welding gun (3); It also includes an insulated gate bipolar transistor switch, which is used to alternately control the power on and off of the non-melting electrode inert gas shielded arc welding gun (2) and the melting electrode active gas shielded welding gun (3); The welding is performed by alternating a DC positive connection non-melting electrode inert gas shielded arc welding-laser composite heat source and a DC reverse connection melting electrode active gas shielded welding-laser composite heat source.

2. The laser-arc hybrid welding equipment for aluminum alloy according to claim 1, characterized in that: The laser beam is a fiber laser or a YAG laser, the focal length of the laser beam is 150 mm to 500 mm, and the focal spot diameter of the laser beam is 0.2 mm to 0.6 mm.

3. The laser-arc hybrid welding equipment for aluminum alloy according to claim 1, characterized in that: The vertical distance between the tip of the tungsten electrode of the non-melting electrode inert gas shielded arc welding gun (2) and the surface of the workpiece to be welded is 1.5 mm to 5 mm, and the horizontal distance between the tip of the tungsten electrode and the scanning center of the laser beam is 2 mm to 3 mm. The horizontal distance between the melting electrode welding wire of the melting electrode active gas shielded arc welding gun (3) and the scanning center of the laser beam is 1 mm to 2 mm.

4. A welding method for aluminum alloy using the laser-arc hybrid welding equipment according to claims 1 to 3, characterized in that: The following steps are involved: S1: the non-melting electrode inert gas shielded arc welding torch (2) and the melting electrode active gas shielded arc welding torch (3) ignite arcs alternately, and simultaneously act on the butt joint of the workpieces to be welded with the laser beam to form a eutectic pool; S2: while the non-melting inert gas shielded arc welding gun (2) ignites the arc, a low-power laser pulse is triggered, and at the same time, the focus of the laser beam is adjusted to the surface of the workpiece to be welded, the non-melting inert gas shielded arc welding gun (2) and the low-power laser pulse form a composite heat source; the arc ignition time of the non-melting inert gas shielded arc welding gun (2) is 5-10ms; the energy ratio of the non-melting inert gas shielded arc welding gun (2) to the low-power laser pulse during the welding process is 1.2-1.6; S3: When the metal active gas shielded welding gun (3) ignites the arc, a high-power laser pulse is triggered, and the focus of the laser beam is adjusted to a position 1 / 3-1 / 2 of the molten pool depth from the surface of the workpiece to be welded, and the metal active gas shielded welding gun (3) and the high-power laser pulse form a composite heat source; the arc ignition time of the metal active gas shielded welding gun (3) is 15-25ms; the energy ratio of the metal active gas shielded welding gun (3) to the high-power laser pulse during the welding process is 1.2-1.

6.

5. A welding method according to claim 4, characterized in that: Before welding in step S1, the workpiece to be welded is preheated to reach a set temperature.

6. A welding method according to claim 4, characterized in that: When the arcs are alternately ignited in step S1, the focusing mirror of the laser generating device moves in the vertical direction to adjust the focus point of the laser beam.

7. A welding method according to claim 4, characterized in that: After the welding in step S3, the temperature of the welding area is detected. When the welding area drops to the set preheating temperature at room temperature, high-frequency heating is used to control the temperature to drop to room temperature at a rate of 2-6°C / min.

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