CN107999916A - A kind of double light beam laser-TIG compound silk filling melt-brazing methods of dissimilar material - Google Patents

Abstract

A dual-beam laser-TIG composite wire-filling melting and brazing method for dissimilar materials, which relates to the field of material processing engineering. In order to solve the problems existing in the laser-arc composite welding process of dissimilar materials, the present invention combines laser and TIG electric arc with The composite form is applied to the welding of dissimilar materials. Two laser beams with different energies are arranged in parallel, and the double beams act on the groove of the base metal on both sides respectively. The method of the present invention can control the distribution of the welding temperature field and improve the welding stability and thermal efficiency. Improve the adaptability to welded joints, improve the microstructure of welds, and reduce welding defects.

Description

A dual-beam laser-TIG composite wire-filling fusion brazing method for dissimilar materials

technical field

The invention belongs to the field of material processing engineering, and in particular relates to a double-beam laser-TIG composite wire-filling fusion brazing method for dissimilar materials.

Background technique

The development of modern industry and the advancement of science and technology have put forward higher and more stringent requirements for the performance of welded components. In addition to the usual mechanical properties, there are also high-temperature strength, wear resistance, corrosion resistance, and low-temperature toughness. , magnetism, electrical conductivity, thermal conductivity and many other performance requirements. In this case, it is impossible for any kind of metal material to fully meet the requirements of the overall welded structure. Therefore, various departments of modern industrial production will inevitably and often encounter the problem of dissimilar material welding.

The characteristic of welded components of dissimilar materials is that they can maximize the use of the respective advantages of the materials and achieve the effect of "making the best use of everything". However, welding dissimilar materials is usually more difficult than welding the same material, because in addition to the influence of the physical and chemical properties of the material itself on the weldability, the difference in the properties of the two materials will affect the weldability between them to a greater extent, Therefore, traditional fusion welding cannot solve the welding problem of dissimilar materials.

During the brazing process of dissimilar materials, the matrix does not melt, which can prevent the large-scale generation of intermetallic compounds. At the same time, the welding parameters have good controllability. The thickness of the intermetallic compound layer can be controlled by adjusting the welding parameters. The composition of the solder is used to precisely control the interfacial reaction process, so as to obtain dissimilar metal joints with good mechanical properties. However, the welded joint obtained by this method has low strength, poor heat resistance, strict cleaning requirements before welding, high welding cost, low welding efficiency, is not suitable for mass production, and greatly reduces practical applicability. Therefore, special welding methods and technological measures are required.

Therefore, at present, the welding of dissimilar materials generally adopts the fusion brazing method. Generally, the brazing joint is formed on the side of the high melting point base metal, and the fusion welding joint is formed on the side of the low melting point base metal. Among them, laser welding and arc welding are two current research hotspots.

Laser welding has the characteristics of high energy density, fast welding speed, high welding precision, large weld depth-to-width ratio, small heat-affected zone, small welding deformation, strong adaptability and easy automatic welding. Therefore, when welding dissimilar materials by laser welding It can obtain extremely small melting zone and heat-affected zone, reduce the internal stress in the weld, and can purify the weld to reduce defects such as slag inclusions, pores and cracks. Patent 201310384366 discloses a laser melting-brazing welding process for connecting galvanized steel and aluminum. The joint form is lap joint, which is different from butt joints, and when applied to butt joints, the assembly requirements are relatively high.

The laser-arc composite heat source welding method is a new, high-quality and efficient welding method developed on the basis of traditional arc welding and laser welding. Laser-arc composite heat source welding is the energy A new type of material processing method that acts on the workpiece in a certain way and generates the same molten pool through the interaction of the two to achieve high-quality and efficient welding. Arc-assisted laser welding can effectively improve the problems existing in laser welding. Patent 200610007614 discloses a method for joining dissimilar metals with a large-spot laser and an arc composite heat source. The wettability of the weld metal has been greatly improved by using MAG. Defects such as weld penetration may result.

Contents of the invention

The invention aims to solve the problems existing in the laser-arc composite welding process of dissimilar materials, and proposes a dual-beam laser-TIG composite wire-filling welding method for dissimilar materials.

A double-beam laser-TIG composite wire-filling welding method for dissimilar materials of the present invention, it is carried out according to the following steps:

Step 1: Before welding, process the parts to be welded into Y-shaped grooves, I-shaped grooves or asymmetrical grooves according to the plate thickness, and grind the processed grooves and the surfaces on both sides Or cleaning, fix the workpiece to be welded after grinding or cleaning on the welding fixture;

Step 2: Use the fixture to rigidly fix the laser head, TIG welding torch and wire feeding mechanism;

Step 3: Set welding process parameters:

The laser power is 1kW~4kW, the power ratio of the two laser beams is 1:1~1:10, the defocus range is -2~+10mm, the distance between the centers of the two laser beams is 2~6mm, and Ar gas is used for protection. 15L/min～50L/min; arc current 30～90A, welding speed 0.3～5m/min, wire feeding speed 0.2～8m/min;

Once the above welding process parameters are determined, they will remain unchanged during the welding process;

Step 4: In the actual welding process, the robot integrated system is used to control the welding process parameters. First, the TIG arc is started. After the arc is stable for 1 second, the laser is controlled to emit laser light, and then the wire feeder feeds the welding wire. Finally, the robot is controlled to make the laser working head and The joint motion of the TIG torch completes the welding process.

The double-beam laser-TIG composite filler welding method for dissimilar materials refers to the application of laser and TIG arc in the welding of dissimilar materials in a composite form. Two laser beams with different energies are arranged in parallel, and the double beams act on both sides respectively. on the parent metal groove. The laser beam is divided into a main beam with higher energy and a sub-beam with lower energy. The main beam cooperates with the welding wire, and the sub-beam cooperates with the TIG arc. The main beam is deflected to the side of the base metal with a high melting point, and is mainly used to melt the welding wire. The molten welding wire and solder fall on the base metal in the form of a liquid bridge transition for wetting and spreading to form a brazed joint; the sub-beam is combined with the TIG arc Working together on the side of the low melting point base metal, the sub-beam is used to stabilize the TIG arc. The TIG arc mainly plays the role of melting the low melting point base metal, forming a smaller volume of molten pool on the low melting point base metal, and finally forming a welded joint . The molten pool formed on the side of the base metal with a low melting point is fused with the molten and spread welding wire on the side of the base metal with a high melting point to form a welded joint of dissimilar materials. Its schematic diagram is shown in Figure 1.

Because the laser energy is precisely and controllable, it can melt the welding wire without directly acting on the base metal or only preheating the base metal. On the side of the base metal with low melting point, because the molten pool formed by a single laser is too small and the cooling is too fast, it is not conducive to its wetting and spreading and connecting with the brazed joint, and the general welding base material is high reflectivity such as aluminum and magnesium. For materials, it is difficult to directly form a stable molten pool with a single laser or the energy loss is too large. Therefore, a small current TIG arc is used to recombine with the secondary laser beam. At the same time, in order to enhance the flow and spreadability of the molten pool, the embodiments of the present invention are not limited to those shown in the illustration. method, you can also install a wire feeding device in front of the TIG welding torch, add more welding wire, etc.

In the welding of dissimilar materials, the method of dual-beam laser-TIG composite filler wire fusion brazing has the following advantages compared with traditional dissimilar material welding:

(1) Control the distribution of the welding temperature field: by controlling the power distribution and defocus of the two laser beams to control the heat input to the base metal on both sides, avoiding the melting and cracking caused by the direct heating of the high melting point base metal by the heat source Problems, to achieve high-quality, efficient connection of dissimilar materials.

(2) Improve welding stability and thermal efficiency: the TIG arc with small current is stabilized by the attraction of the laser to the arc. In addition, the addition of the laser can improve the thermal efficiency of the TIG arc melting the base metal, and further reduce the heat input.

(3) Improve the adaptability of welding joints: In laser-arc composite heat source welding, due to the large adjustable range of thermal action of the arc and the strong bridging ability of molten pool metal, welding can be realized under a large assembly gap .

(4) Improve the microstructure of the weld and reduce welding defects: by adjusting the welding process parameters, the direct action range of the heat source on the base metal can be controlled, the thickness of the intermetallic compound layer at the brazing interface of the high melting point base metal can be adjusted, and multiple welding wires can be added through metallurgy The effect is to improve the welding seam structure on the side of the base metal with low melting point.

Description of drawings

Figure 1 is a schematic diagram of double-beam laser-TIG composite filler wire fusion brazing;

Fig. 2 is the welded seam front appearance photo that embodiment 1 method obtains;

Fig. 3 is the photograph of the weld cross-section topography that embodiment 1 method obtains;

Fig. 4 is the welded seam front appearance photo that embodiment 2 method obtains;

Figure 5 is a photo of the cross-sectional appearance of the weld seam obtained by the method in Example 2.

Detailed ways

Specific embodiment 1: This embodiment is described in conjunction with Fig. 1, a kind of double-beam laser-TIG composite filling wire fusion brazing method of dissimilar materials, it is carried out according to the following steps:

Step 1: Before welding, process the parts to be welded into Y-shaped grooves, I-shaped grooves or asymmetrical grooves according to the plate thickness, and grind the processed grooves and the surfaces on both sides Or cleaning, fix the workpiece to be welded after grinding or cleaning on the welding fixture;

Step 2: Use the fixture to rigidly fix the laser head, TIG welding torch and wire feeding mechanism;

Step 3: Set welding process parameters:

The laser power is 1kW~4kW, the power ratio of the two laser beams is 1:1~1:10, the defocus range is -2~+10mm, the distance between the centers of the two laser beams is 2~6mm, and Ar gas is used for protection. 15L/min～50L/min; arc current 30～90A, welding speed 0.3～5m/min, wire feeding speed 0.2～8m/min;

Once the above welding process parameters are determined, they will remain unchanged during the welding process;

Step 4: In the actual welding process, the robot integrated system is used to control the welding process parameters. First, the TIG arc is started. After the arc is stable for 1 second, the laser is controlled to emit laser light, and then the wire feeder feeds the welding wire. Finally, the robot is controlled to make the laser working head and The joint motion of the TIG torch completes the welding process.

Embodiment 2: This embodiment is described with reference to FIG. 1 . The difference between this embodiment and Embodiment 1 is that the dissimilar materials are steel and non-ferrous metal materials or dissimilar non-ferrous metal materials. Others are the same as in the first embodiment.

Embodiment 3: This embodiment is described in conjunction with FIG. 1 . The difference between this embodiment and Embodiment 1 is that the laser used in welding is a _CO2 gas laser, a YAG solid-state laser, a semiconductor laser or a fiber laser. Others are the same as in the first embodiment.

Embodiment 4: This embodiment is described in conjunction with FIG. 1 . The difference between this embodiment and Embodiment 1 is that the welding process parameters are set:

The laser power is 1kW～3kW, the power ratio of the two laser beams is 1:1～1:8, the defocus is 0～+10mm, the distance between the centers of the two laser beams is 2～5mm, and the Ar gas is used for protection, and the Ar gas flow rate is 15L/min～40L/min; arc current 30～80A, welding speed 0.3～4m/min, wire feeding speed 0.2～6m/min.

Others are the same as in the first embodiment.

Embodiment 5: This embodiment is described in conjunction with FIG. 1. The difference between this embodiment and Embodiment 1 is that the welding process parameters are set:

The laser power is 1kW ~ 3kW, the power ratio of the two laser beams is 1:1 ~ 1:6, the defocus is +2 ~ +10mm, the distance between the centers of the two laser beams is 2 ~ 4mm, and the Ar gas is used for protection. 20L/min~40L/min; arc current 30~60A, welding speed 0.3~2m/min, wire feeding speed 0.2~5m/min.

Others are the same as in the first embodiment.

Specific embodiment six: This embodiment is described in conjunction with Fig. 1. The difference between this embodiment and specific embodiment one is: setting welding process parameters:

The laser power is 1kW ~ 3kW, the power ratio of the two laser beams is 1:1 ~ 1:5, the defocus is +3 ~ +10mm, the distance between the centers of the two laser beams is 3 ~ 4mm, and the Ar gas is used for protection. 30L/min~40L/min; arc current 30~50A, welding speed 0.5~2m/min, wire feeding speed 0.5~5m/min.

Others are the same as in the first embodiment.

Embodiment 7: This embodiment is described in conjunction with FIG. 1. The difference between this embodiment and Embodiment 1 is that the welding process parameters are set:

The laser power is 1kW ~ 3kW, the power ratio of the two laser beams is 1:1 ~ 1:3, the defocus is +5 ~ +10mm, the distance between the centers of the two laser beams is 3 ~ 4mm, and the Ar gas is used for protection. 30L/min~40L/min; arc current 30~50A, welding speed 1~2m/min, wire feeding speed 1~5m/min.

Others are the same as in the first embodiment.

Embodiment 8: This embodiment is described in conjunction with FIG. 1. The difference between this embodiment and Embodiment 1 is that the welding process parameters are set:

The laser power is 1kW ~ 3kW, the power ratio of the two laser beams is 1:1 ~ 1:3, the defocus is +5 ~ +8mm, the distance between the centers of the two laser beams is 3 ~ 4mm, and Ar gas is used for protection. 30L/min~40L/min; arc current 30~50A, welding speed 1~2m/min, wire feeding speed 1~3m/min.

Others are the same as in the first embodiment.

Specific embodiment nine: This embodiment is described in conjunction with Fig. 1. The difference between this embodiment and specific embodiment one is: setting welding process parameters:

The laser power is 3kW, the power ratio of the two laser beams is 1:3, the defocus is +5mm, the distance between the centers of the two laser spots is 3mm, Ar gas protection is used, and the Ar gas flow rate is 30L/min; the arc current is 50A, and the welding The speed is 1.6m/min, and the wire feeding speed is 3m/min.

Others are the same as in the first embodiment.

Embodiment 10: This embodiment is described in conjunction with FIG. 1. The difference between this embodiment and Embodiment 1 is that the welding process parameters are set:

The laser power is 2kW, the power ratio of the two laser beams is 1:5, the defocus is +3mm, the distance between the centers of the two laser spots is 3mm, Ar gas protection is used, and the Ar gas flow rate is 30L/min; the arc current is 50A, and the welding The speed is 2m/min, and the wire feeding speed is 5m/min.

Others are the same as in the first embodiment.

The content of the present invention is not limited to the content of the above-mentioned embodiments, and a combination of one or several specific embodiments can also achieve the purpose of the invention.

Verify the beneficial effects of the present invention through the following examples:

Example 1

In this embodiment, the welding of aluminum\steel dissimilar materials is taken as an example, and a 2mm thick 6061-T6 aluminum alloy and a 2mm thick Q235 galvanized steel are welded by using a double-beam laser-TIG composite filler wire melting brazing method and a laser filler wire welding method Butt joint, the specific experimental method is as follows:

The method of this embodiment welds the butt joint of 2mm thick 6061-T6 aluminum alloy plate and Q235 galvanized steel plate:

Step 1: Before welding, according to the thickness of the plate, process the steel plate to be welded with a 30° groove, and the aluminum plate to be welded with a 45° groove, and grind or clean the processed groove and the surfaces on both sides. After cleaning, the workpiece to be welded is fixed on the welding fixture;

Step 2: Use a special fixture to rigidly fix the laser head, TIG welding torch and wire feeding mechanism;

Step 3: Set welding process parameters:

According to the thickness of the workpiece to be welded, the laser power is 3kW, the power ratio of the two laser beams is 1:3, the defocus distance is 5mm, the distance between the centers of the two laser beams is 3mm, and Ar gas protection is used, and the Ar gas flow rate is 30L/min; The current is 50A, the welding speed is 1.6m/min, and the wire feeding speed is 3m/min.

Once the above welding process parameters are determined, they will remain unchanged during the welding process;

Step 4: In the actual welding process, the robot integrated system is used to control the welding process parameters. First, the TIG arc is started. After the arc is stable for 1 second, the laser is controlled to emit laser light, and then the wire feeder feeds the welding wire. Finally, the robot is controlled to make the laser working head and The joint motion of the TIG torch completes the welding process.

Fig. 2 is the front appearance and the cross-sectional appearance of the welding seam of the 2mm thick 6061-T6 aluminum alloy plate and the Q235 galvanized steel plate butt joint welded by the method of this embodiment, it can be seen that when the method is used for aluminum/steel welding , The welding process is relatively stable, the surface of the weld is well formed, and there are no forming defects such as welding penetration and collapse. It can be seen from the cross-sectional metallography that the base metal on the steel side has not undergone obvious melting, and no welding hot cracks have been found after testing.

Example 2

In this example, as a comparative example, the butt joint of a 2mm thick 6061-T6 aluminum alloy plate and a Q235 galvanized steel plate is welded by laser wire-filled welding method:

Step 1: Before welding, according to the thickness of the plate, process the steel plate to be welded with a 30° groove, and the aluminum plate to be welded with a 45° groove, and grind or clean the processed groove and the surfaces on both sides. After cleaning, the workpiece to be welded is fixed on the welding fixture;

Step 2: Use a special fixture to rigidly fix the laser head, TIG welding torch and wire feeding mechanism;

Step 3: Set welding process parameters:

According to the thickness of the workpiece to be welded, the laser power is 2.5kW, the defocus is +5mm, Ar gas protection is used, and the Ar gas flow rate is 30L/min; the welding speed is 1.0m/min, the wire feeding speed is 2.5m/min, and the light The wire spacing is 1mm.

Once the above welding process parameters are determined, they will remain unchanged during the welding process

Step 4: In the actual welding process, the robot integrated system is used to control the welding process parameters. First, the TIG arc is started. After the arc is stable for 1 second, the laser is controlled to emit laser light, and then the wire feeder feeds the welding wire. Finally, the robot is controlled to make the laser working head and The joint motion of the TIG torch completes the welding process.

Figure 3 shows the front appearance and cross-sectional appearance of the weld seam of the 2mm thick 6061-T6 aluminum alloy plate and the Q235 galvanized steel plate butt joint welded by the method of laser wire filling welding. When the aluminum alloy plate is used, the weld seam is narrow, the amount of sag is large, and the weld seam is poorly formed. It can be seen from the metallography of the cross section that the content of pores in the weld increases, and there are a small number of pits on the surface of the weld, which are incomplete overflow pores. The base metal on the steel side is obviously melted, and the thickness of the interface layer increases. Thick interfacial layer with microcracks present.

From the comparison of Example 1 and Example 2, it can be seen that the method adopted in Example 1 has obvious advantages.

Example 3

In this embodiment, the welding of aluminum\steel dissimilar materials is taken as an example, and a 2mm thick 6061-T6 aluminum alloy and a 2mm thick Q235 galvanized steel are welded by using a double-beam laser-TIG composite filler wire melting brazing method and a laser filler wire welding method Butt joint, the specific experimental method is as follows:

The method of this embodiment welds the butt joint of 2mm thick 6061-T6 aluminum alloy plate and Q235 galvanized steel plate:

Step 1: Before welding, according to the thickness of the plate, process the steel plate to be welded with a 30° groove, and the aluminum plate to be welded with a 45° groove, and grind or clean the processed groove and the surfaces on both sides. After cleaning, the workpiece to be welded is fixed on the welding fixture;

Step 2: Use a special fixture to rigidly fix the laser head, TIG welding torch and wire feeding mechanism;

Step 3: Set welding process parameters:

According to the thickness of the workpiece to be welded, the laser power is 2kW, the power ratio of the two laser beams is 1:5, the defocus distance is 6mm, the distance between the centers of the two laser beams is 4mm, Ar gas protection is used, and the Ar gas flow rate is 40L/min; The current is 30A, the welding speed is 2m/min, and the wire feeding speed is 5m/min.

Once the above welding process parameters are determined, they will remain unchanged during the welding process;

Step 4: In the actual welding process, the robot integrated system is used to control the welding process parameters. First, the TIG arc is started. After the arc is stable for 1 second, the laser is controlled to emit laser light, and then the wire feeder feeds the welding wire. Finally, the robot is controlled to make the laser working head and The joint motion of the TIG torch completes the welding process.

Example 4

In this embodiment, the welding of aluminum\steel dissimilar materials is taken as an example, and a 2mm thick 6061-T6 aluminum alloy and a 2mm thick Q235 galvanized steel are welded by using a double-beam laser-TIG composite filler wire melting brazing method and a laser filler wire welding method Butt joint, the specific experimental method is as follows:

The method of this embodiment welds the butt joint of 2mm thick 6061-T6 aluminum alloy plate and Q235 galvanized steel plate:

Step 1: Before welding, according to the thickness of the plate, process the steel plate to be welded with a 30° groove, and the aluminum plate to be welded with a 45° groove, and grind or clean the processed groove and the surfaces on both sides. After cleaning, the workpiece to be welded is fixed on the welding fixture;

Step 2: Use a special fixture to rigidly fix the laser head, TIG welding torch and wire feeding mechanism;

Step 3: Set welding process parameters:

According to the thickness of the workpiece to be welded, the laser power is 1kW, the power ratio of the two laser beams is 1:1, the defocus distance is -2mm, the distance between the centers of the two laser beams is 2mm, Ar gas protection is used, and the Ar gas flow rate is 15L/min; The arc current is 15A, the welding speed is 0.3m/min, and the wire feeding speed is 0.2m/min.

Once the above welding process parameters are determined, they will remain unchanged during the welding process;

Step 4: In the actual welding process, the robot integrated system is used to control the welding process parameters. First, the TIG arc is started. After the arc is stable for 1 second, the laser is controlled to emit laser light, and then the wire feeder feeds the welding wire. Finally, the robot is controlled to make the laser working head and The joint motion of the TIG torch completes the welding process.

Example 5

In this embodiment, the welding of aluminum\steel dissimilar materials is taken as an example, and a 2mm thick 6061-T6 aluminum alloy and a 2mm thick Q235 galvanized steel are welded by using a double-beam laser-TIG composite filler wire melting brazing method and a laser filler wire welding method Butt joint, the specific experimental method is as follows:

The method of this embodiment welds the butt joint of 2mm thick 6061-T6 aluminum alloy plate and Q235 galvanized steel plate:

Step 1: Before welding, according to the thickness of the plate, process the steel plate to be welded with a 30° groove, and the aluminum plate to be welded with a 45° groove, and grind or clean the processed groove and the surfaces on both sides. After cleaning, the workpiece to be welded is fixed on the welding fixture;

Step 2: Use a special fixture to rigidly fix the laser head, TIG welding torch and wire feeding mechanism;

Step 3: Set welding process parameters:

According to the thickness of the workpiece to be welded, the laser power is 4kW, the power ratio of the two laser beams is 1:10, the defocus distance is 10mm, and the center distance between the two laser beams is 6mm. Ar gas protection is used, and the Ar gas flow rate is 50L/min; The current is 90A, the welding speed is 5m/min, and the wire feeding speed is 8m/min.

Once the above welding process parameters are determined, they will remain unchanged during the welding process;

Step 4: In the actual welding process, the robot integrated system is used to control the welding process parameters. First, the TIG arc is started. After the arc is stable for 1 second, the laser is controlled to emit laser light, and then the wire feeder feeds the welding wire. Finally, the robot is controlled to make the laser working head and The joint movement of the TIG torches completes the welding process.

Claims (10)

1. A double-beam laser-TIG composite wire-filling fusion brazing method for dissimilar materials is characterized in that it is carried out according to the following steps: Step 1: Before welding, process the parts to be welded into Y-shaped grooves, I-shaped grooves or asymmetrical grooves according to the plate thickness, and grind the processed grooves and the surfaces on both sides Or cleaning, fix the workpiece to be welded after grinding or cleaning on the welding fixture; Step 2: Use the fixture to rigidly fix the laser head, TIG welding torch and wire feeding mechanism; Step 3: Set welding process parameters: The laser power is 1kW~4kW, the power ratio of the two laser beams is 1:1~1:10, the defocus range is -2~+10mm, the distance between the centers of the two laser beams is 2~6mm, and Ar gas is used for protection. 15L/min～50L/min; arc current 30～90A, welding speed 0.3～5m/min, wire feeding speed 0.2～8m/min; Once the above welding process parameters are determined, they will remain unchanged during the welding process; Step 4: In the actual welding process, the robot integrated system is used to control the welding process parameters. First, the TIG arc is started. After the arc is stable for 1 second, the laser is controlled to emit laser light, and then the wire feeder feeds the welding wire. Finally, the robot is controlled to make the laser working head and The joint movement of the TIG torches completes the welding process. 2. The method of dual-beam laser-TIG composite wire-filling fusion brazing of dissimilar materials according to claim 1, characterized in that the dissimilar materials are steel and non-ferrous metal dissimilar materials or dissimilar non-ferrous metal materials. 3. a kind of dissimilar material according to claim 1 double-beam laser-TIG composite wire-filling melting and brazing method, it is characterized in that the laser that adopts in welding is _CO gas laser, YAG solid-state laser, semiconductor laser or fiber laser . 4. The double-beam laser-TIG composite wire-filling fusion brazing method of a kind of dissimilar material according to claim 1 is characterized in that welding process parameters are set: The laser power is 1kW～3kW, the power ratio of the two laser beams is 1:1～1:8, the defocus is 0～+10mm, the distance between the centers of the two laser beams is 2～5mm, and the Ar gas is used for protection, and the Ar gas flow rate is 15L/min～40L/min; arc current 30～80A, welding speed 0.3～4m/min, wire feeding speed 0.2～6m/min. 5. a kind of dissimilar material according to claim 4 double-beam laser-TIG composite wire-filling fusion brazing method, it is characterized in that welding process parameter is set: The laser power is 1kW ~ 3kW, the power ratio of the two laser beams is 1:1 ~ 1:6, the defocus is +2 ~ +10mm, the distance between the centers of the two laser beams is 2 ~ 4mm, and the Ar gas is used for protection. 20L/min~40L/min; arc current 30~60A, welding speed 0.3~2m/min, wire feeding speed 0.2~5m/min. 6. The dual-beam laser-TIG composite wire-filling fusion brazing method of a kind of dissimilar material according to claim 5 is characterized in that welding process parameters are set: The laser power is 1kW ~ 3kW, the power ratio of the two laser beams is 1:1 ~ 1:5, the defocus is +3 ~ +10mm, the distance between the centers of the two laser beams is 3 ~ 4mm, and the Ar gas is used for protection. 30L/min~40L/min; arc current 30~50A, welding speed 0.5~2m/min, wire feeding speed 0.5~5m/min. 7. The double-beam laser-TIG composite wire-filling fusion brazing method of a kind of dissimilar material according to claim 6, characterized in that welding process parameters are set: The laser power is 1kW ~ 3kW, the power ratio of the two laser beams is 1:1 ~ 1:3, the defocus is +5 ~ +10mm, the distance between the centers of the two laser beams is 3 ~ 4mm, and the Ar gas is used for protection. 30L/min~40L/min; arc current 30~50A, welding speed 1~2m/min, wire feeding speed 1~5m/min. 8. The double-beam laser-TIG composite wire-filling fusion brazing method of a kind of dissimilar material according to claim 7, characterized in that welding process parameters are set: The laser power is 1kW ~ 3kW, the power ratio of the two laser beams is 1:1 ~ 1:3, the defocus is +5 ~ +8mm, the distance between the centers of the two laser beams is 3 ~ 4mm, and Ar gas is used for protection. 30L/min~40L/min; arc current 30~50A, welding speed 1~2m/min, wire feeding speed 1~3m/min. 9. The double-beam laser-TIG composite wire-filling fusion brazing method of a kind of dissimilar material according to claim 1, characterized in that welding process parameters are set: The laser power is 3kW, the power ratio of the two laser beams is 1:3, the defocus is +5mm, the distance between the centers of the two laser beams is 3mm, Ar gas protection is used, and the Ar gas flow rate is 30L/min; the arc current is 50A, and the welding The speed is 1.6m/min, and the wire feeding speed is 3m/min. 10. The dual-beam laser-TIG composite filler wire melting and brazing method for dissimilar materials according to claim 1, characterized in that welding process parameters are set: The laser power is 2kW, the power ratio of the two laser beams is 1:5, the defocus is +3mm, the distance between the centers of the two laser spots is 3mm, Ar gas protection is used, and the Ar gas flow rate is 30L/min; the arc current is 50A, and the welding The speed is 2m/min, and the wire feeding speed is 5m/min.