Narrow-gap swinging laser-MIG composite wire filling welding equipment and method for thick-wall component

Abstract

The invention discloses narrow-gap swing laser-MIG composite filler wire welding equipment and method for a thick-wall component, belongs to the field of thick-wall component welding, and aims to solve the problems that the side wall of a narrow-gap groove of a thick plate of 50-250 mm is not fused and the welding efficiency is low. The swinging narrow-gap MIG welding gun and the auxiliary wire feeding pipe are arranged on the two sides of the laser, dynamic cooperation of the main / auxiliary double wire feeding systems is adopted, the dynamic characteristics of a molten pool are improved in combination with laser spot swinging, and the deposition efficiency is improved. The heating range of the composite heat source is expanded through the coupling effect of swing laser and electric arc, sufficient fusion of the side wall is ensured, meanwhile, bubble discharging is promoted through molten pool stirring, grains are refined, and the welding seam quality is improved. The laser and the MIG electric arc form a composite energy field, the auxiliary welding wire is directly melted, the energy utilization rate is remarkably improved, the deposition amount in unit time is increased by 30%-50%, the single-layer single-pass welding thickness can reach 3 mm-5 mm, the welding passes are reduced compared with a traditional MIG fuse wire mode, and the method is suitable for efficient and high-quality thick plate welding.

Description

Technical Field

[0001] The present invention belongs to the field of thick-walled component welding. Specifically, it relates to a narrow-gap oscillating laser-MIG composite wire-filling welding device for thick-walled components; and a narrow-gap oscillating laser-MIG composite wire-filling welding method for thick-walled components; which is particularly suitable for the high-efficiency and high-quality welding of thick plate materials. Background Art

[0002] With the increasing demand for large components with high service performance in the fields of water conservancy and hydropower, nuclear power, ships, and rail transit, etc., the precision high-quality welding technology for thick-walled components (such as stainless steel, high-strength steel, aluminum alloy, titanium alloy, nickel-based alloy, etc.) has become the key technical bottleneck restricting the development of equipment manufacturing. The traditional thick plate welding process generally adopts the single-sided or double-sided large-angle groove welding method, which has problems such as excessive heat input, significant welding deformation, high interlayer defect rate, and low production efficiency. Although the narrow-gap welding technology developed in recent years can effectively reduce the consumption of welding materials, control welding deformation, and improve production efficiency to a certain extent, conventional narrow-gap welding still has inherent defects such as poor sidewall fusion and high porosity sensitivity.

[0003] The laser-arc hybrid welding technology combines the dual advantages of laser welding and arc welding. With characteristics such as large penetration depth, high forming rate, and low thermal deformation, it shows significant advantages in the welding of thick-walled components. However, the simple combination of laser and arc in the prior art is difficult to achieve synergistic efficiency improvement and still has certain limitations: First, the traditional MIG single-sided wire-fusing mode not only limits the wire deposition efficiency but also leads to insufficient molten pool fluidity, hindering the full diffusion of molten metal in multi-pass welding, and then resulting in uneven weld formation, porosity, and lack of fusion and other defects. Second, although the high energy density of the laser is conducive to achieving deep penetration welding, its stirring effect on the molten pool is insufficient, easily causing uneven heat distribution inside the molten pool, which not only exacerbates the tendency of porosity formation but also reduces the sidewall fusion stability, ultimately affecting the mechanical properties of the joint. In addition, when welding under narrow-gap conditions, the traditional welding torch structure is difficult to adapt to precise operation in a narrow space, and the spatial coupling efficiency of the arc and laser hybrid heat source is relatively low, resulting in poor sidewall fusion of the groove and uneven distribution of filler metal. Although existing improvement schemes (such as oscillating arc, optimizing the groove geometry) can improve the filling effect, they still face challenges such as process complexity and insufficient precision in heat input regulation. Therefore, it is urgent to develop a new type of hybrid welding technology to break through the bottleneck of wire deposition efficiency, enhance the dynamic regulation ability of the molten pool, and improve the adaptability and reliability of narrow-gap welding. Summary of the Invention

[0004] Aiming at the problems existing in the existing laser-arc hybrid welding technology for thick-walled components, the present invention provides a narrow-gap oscillating laser-MIG composite wire-filling welding device and method for thick-walled components.

[0005] Through the dynamic cooperative control mechanism of the main / auxiliary dual wire feeding system and combined with the composite motion trajectory formed by the laser spot swing and the narrow-gap MIG welding torch swing, the present invention can significantly improve the dynamic characteristics of the molten pool, solve the problem of fusion between the weld and the side wall of the base material, and improve the wire deposition efficiency, ultimately achieving high-quality connection of thick-walled components.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides a narrow-gap oscillating laser-MIG composite wire filling welding device for thick-walled components, including a laser welding mechanism, a MIG welding mechanism, an auxiliary wire feeding mechanism, a gas protection mechanism, and a mechanical installation mechanism. The MIG welding mechanism, the laser welding mechanism, and the auxiliary wire feeding mechanism are arranged in sequence along the welding direction. The laser welding mechanism is used to efficiently melt the auxiliary-side wire and cooperate with the arc to form a composite energy field, strengthening the stirring effect of the molten pool through the coupling effect of the laser and the arc; the MIG welding mechanism is used for weld bead filling; the auxiliary wire feeding mechanism is used to cooperate with the laser welding mechanism to perform auxiliary filling of the groove, improving the deposition efficiency; the gas protection mechanism is used to protect the welding molten pool to prevent oxidation of the liquid metal; the mechanical installation mechanism is used to install and fix the laser welding mechanism, the MIG welding mechanism, and the auxiliary wire feeding mechanism.

[0008] Further defined, the laser welding mechanism includes a laser and an oscillating laser welding torch. The power of the laser is 2 kW to 10 kW; the oscillating laser welding torch can output various oscillation modes (such as circular, infinite, sine, linear), with an oscillation frequency of 0 Hz to 200 Hz, an amplitude of 0 mm to 5 mm. The axis of the oscillating laser welding torch is perpendicular to the welding direction and corresponds to the weld of the base material to be welded.

[0009] Further defined, the MIG welding mechanism includes a MIG power source and an oscillating narrow-gap MIG welding torch. The positive pole of the MIG power source is connected to the oscillating narrow-gap MIG welding torch, and the negative pole is connected to the base material to be welded; the oscillating narrow-gap MIG welding torch is a narrow-gap welding torch with an ultra-thin structure (10 mm), provided with a MIG welding torch conductive wire feeding nozzle, having an oscillation function with an oscillation frequency of 0 Hz to 20 Hz and an oscillation angle of 0° to 30°. The MIG welding torch conductive wire feeding nozzle forms an angle of 15° to 45° with the axis of the laser beam formed by the laser, and the distance between the wire and the laser beam is 4 mm to 6 mm.

[0010] Further defined, the auxiliary wire feeding mechanism includes a bypass hot wire power supply, an auxiliary wire feeding tube, and a hot wire joint. The bypass hot wire power supply is connected to the auxiliary wire feeding tube through the hot wire joint and has a heating function for the welding wire; the auxiliary side welding wire is fed into the bottom of the groove through the auxiliary wire feeding tube, and the wire feeding speed can be independently adjusted. The wire feeding ratio with the oscillating narrow-gap MIG welding torch is (0.5 - 2):1. The auxiliary wire feeding tube forms an angle of 50° - 70° with the axis of the laser beam formed by the laser. The auxiliary side welding wire intersects with the focal point of the beam at one point and acts on the same welding molten pool together.

[0011] Further defined, the gas protection mechanism includes a shielding gas nozzle I, a shielding gas nozzle II, and an upper shielding gas cover. The shielding gas nozzle I, the shielding gas nozzle II, and the upper shielding gas cover are respectively arranged behind the auxiliary wire feeding tube, directly above the conductive wire feeding nozzle of the MIG welding torch, and directly above the welding area. The flow rates of the shielding gas nozzle I and the shielding gas nozzle II are 15 L / min - 25 L / min, and the gas pressure value of the upper shielding gas cover is 0.2 MPa - 0.3 MPa.

[0012] The present invention also provides a narrow-gap oscillating laser-MIG composite wire filling welding method for thick-walled components, which specifically includes the following steps:

[0013] Step 1: According to the working range of the laser-MIG composite welding equipment, design and machine a narrow-gap groove on the base material to be welded.

[0014] Step 2: Remove the surface oxide layer of the area to be welded by mechanical grinding, and then clean it with anhydrous ethanol to ensure that the surface of the base material to be welded is clean and free of oil.

[0015] Step 3: Through the mechanical installation mechanism, arrange the MIG welding mechanism, the laser welding mechanism, and the auxiliary wire feeding mechanism in sequence along the welding direction, and install the corresponding gas protection mechanism respectively behind the auxiliary wire feeding tube, directly above the conductive wire feeding nozzle of the MIG welding torch, and directly above the welding area.

[0016] Step 4: Adjust and confirm that the oscillating laser welding torch, the auxiliary wire feeding tube, and the oscillating narrow-gap MIG welding torch are in the same plane and the welding paths coincide. The axis of the laser beam is perpendicular to the welding direction. The auxiliary wire feeding tube forms an angle of 50° - 70° with the axis of the laser beam, the conductive wire feeding nozzle of the MIG welding torch forms an angle of 15° - 45° with the axis of the laser beam, and the distance between the MIG welding wire and the laser beam is set to 4 mm - 6 mm.

[0017] Step 5: Set the parameters of auxiliary wire feeding, laser, and MIG arc welding to ensure the stable coupling of hot wire-laser-MIG arc. The welding parameters include welding speed, wire feeding speed, hot wire current, wire diameter, laser defocusing amount, laser power, laser oscillation frequency and amplitude, MIG arc current, voltage, dry elongation of the wire, oscillation angle and frequency of the oscillating MIG welding torch;

[0018] Step 6: Determine the starting and ending welding positions, and synchronously start the oscillating laser welding torch, auxiliary wire feeding tube, and oscillating narrow-gap MIG welding torch. Driven by the composite welding system, the torch group moves along the welding direction at the set welding speed, and the wires on both the left and right sides are synchronously and evenly deposited through the wire feeding mechanism. During the welding process, the addition of auxiliary wire feeding not only avoids the composition segregation defect caused by single-sided wire melting in traditional MIG but also significantly improves the deposition efficiency. The oscillating laser performs dual functions: on the one hand, it melts the auxiliary wire to assist in filling the groove; on the other hand, it forms a laser-arc composite heat source in cooperation with the oscillating arc. In this composite heat source: 1) The arc spreads the molten metal evenly to both sides of the groove through periodic oscillation; 2) The oscillating laser beam fully stirs the molten pool, effectively promoting gas discharge and further refining the grain structure; 3) The coupling effect of the laser and the arc ensures full fusion of the narrow-gap groove sidewalls.

[0019] Step 7: After each weld pass is completed, control the interpass temperature below 150°C, and repeat the filling welding until the entire narrow-gap weld is filled.

[0020] Furthermore, it is specified that during the welding process, the purity of the argon gas used in the gas protection mechanism reaches 99.999%, and the pre-gas supply and post-gas supply time before and after welding are 10 s to 15 s, effectively preventing oxidation of the welded joint.

[0021] Furthermore, it is specified that in Step 1, the welding surfaces of the two base materials to be welded are both machined into small-angle U-grooves, with a root face of 5 mm to 8 mm, a groove angle of 1° to 5°, and a groove radius of 6 mm to 8 mm;

[0022] Furthermore, it is specified that in Step 1, the thickness of the base material to be welded is 50 mm to 250 mm, and the material is stainless steel, high-strength steel, aluminum alloy, titanium alloy, nickel-based alloy, etc.

[0023] Further limited, when welding in step 6, the welding speed is set to 0.5 m / min to 2.0 m / min, the auxiliary wire feeding speed is 4 m / min to 6 m / min, the wire feeding speed of the oscillating narrow-gap MIG welding torch is 5 m / min to 12 m / min, the laser defocus amount is -10 mm to 10 mm, the dry elongation of the wire in the auxiliary wire feeding tube is (10±2) mm, the dry elongation of the wire of the oscillating narrow-gap MIG welding torch is (15±2) mm, the bypass hot wire current is 40 A to 60 A, the MIG arc current is 160 A to 320 A, the voltage is 22 V to 29 V, the oscillation angle of the MIG welding torch is 0° to 30°, and the frequency is 0 Hz to 20 Hz.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention utilizes the coupling effect between the oscillating laser and the oscillating arc to expand the heating range of the composite heat source, ensuring effective fusion of the side walls of the narrow-gap groove. At the same time, it stirs the molten pool, promotes the discharge of bubbles, refines the grains, and improves the weld quality. On the existing basis, in addition to forming a laser-arc composite energy field with the MIG welding arc, the laser in the present invention is also used to melt the auxiliary wire feeding, greatly improving the energy utilization rate, increasing the deposition amount per unit time by 30% to 50%, and the single-layer single-pass weldable thickness reaching 3 mm to 5 mm, reducing the number of welding passes compared with the traditional MIG single-side wire melting mode. At the same time, adding an auxiliary wire is conducive to realizing the uniform distribution of weld elements and avoiding segregation. The present invention comprehensively utilizes the advantages of the two welding methods of laser and arc, improves the energy utilization rate of the welding process, the ultra-thin welding torch structure can realize narrow-gap welding, reduce the groove processing amount by more than 50%, reduce the wire filling amount, and thus reduce the production cost. The present invention uses laser to melt the wire and forms a laser-arc composite energy field with the arc, reducing the heat input during welding, and cooperating with the double-wire rapid filling of the molten pool, to a certain extent reducing the thermal deformation during the welding of thick-walled components. The welding process window of the present invention has a wide adjustment range, the welding process is stable, the weld formation is good, and by adjusting the wire feeding ratio of the double wires and the laser oscillation parameters, it can meet the welding requirements of different materials (such as stainless steel, high-strength steel, titanium alloy, aluminum alloy, nickel-based alloy, etc.).

[0026] In order to further understand the features and technical content of the present invention, please refer to the following detailed description of the present invention and the drawings. However, the attached drawings are only for reference and illustration purposes and are not used to limit the present invention. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of a narrow-gap oscillating laser-MIG composite wire filling welding device for thick-walled components in the present invention;

[0028] Figure 2 It is a schematic diagram of the groove form of the narrow-gap welding base material;

[0029] Figure 3 Cross-sectional photograph of a sample welded by the welding method of a narrow-gap oscillating laser-MIG composite wire-filling welding equipment for thick-walled components

[0030] Figure 1 In the figure, 1 - base metal to be welded; 2 - laser; 3 - oscillating laser welding torch; 4 - laser beam; 5 - MIG power source; 6 - MIG welding torch conductive wire-feeding nozzle; 7 - shielding gas nozzle I; 8 - oscillating narrow-gap MIG welding torch; 9 - bypass hot wire power source; 10 - auxiliary wire-feeding tube; 11 - hot wire joint; 12 - shielding gas nozzle II; 13 - upper shielding gas hood; 14 - weld seam; α - included angle between the laser beam axis and the auxiliary welding wire; β - included angle between the laser beam and the MIG welding wire Specific embodiments

[0031] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further define and understand the present invention, and do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept of the present invention, several deformations and improvements can still be made. These all belong to the protection scope of the present invention

[0032] As Figure 1 shown, a narrow-gap oscillating laser-MIG composite wire-filling equipment for thick-walled components includes a laser welding mechanism, a MIG welding mechanism, an auxiliary wire-feeding mechanism, a gas shielding mechanism, and a mechanical installation mechanism. The laser welding mechanism includes a laser 2 and an oscillating laser welding torch 3; the MIG welding mechanism includes a MIG power source 5 and an oscillating narrow-gap MIG welding torch 8; the auxiliary wire-feeding mechanism includes a bypass hot wire power source 9, an auxiliary wire-feeding tube 10, and a hot wire joint 11; the gas shielding mechanism includes a shielding gas nozzle I 7, a shielding gas nozzle II 12, and an upper shielding gas hood 13

[0033] The laser welding mechanism includes a laser 2 and an oscillating laser welding torch 3. The axis of the laser beam 4 is perpendicular to the welding direction and is correspondingly arranged with the weld seam of the base metal 1 to be welded

[0034] The MIG welding mechanism includes a MIG power source 5 and an oscillating narrow-gap MIG welding torch 8. The positive pole of the MIG power source 5 is connected to the oscillating narrow-gap MIG welding torch 8, and the negative pole is connected to the base metal to be welded; the oscillating narrow-gap MIG welding torch 8 is a narrow-gap welding torch with an ultra-thin structure and is provided with a MIG welding torch conductive wire-feeding nozzle 6

[0035] The auxiliary wire feeding mechanism includes a bypass hot wire power source 9, an auxiliary wire feeding tube 10, and a hot wire connector 11. The bypass hot wire power source 9 is connected to the auxiliary wire feeding tube 10 through the hot wire connector 11 and has a heating function for the welding wire. The auxiliary side welding wire is fed into the bottom of the groove through the auxiliary wire feeding tube 10, and the wire feeding speed can be independently adjusted. The auxiliary side welding wire and the focus of the laser beam intersect at a point and act on the same welding molten pool together.

[0036] The gas protection mechanism includes a shielding gas nozzle I 7, a shielding gas nozzle II 12, and an upper shielding gas hood 13. The shielding gas nozzle I 7, the shielding gas nozzle II 12, and the upper shielding gas hood 13 are respectively arranged behind the auxiliary wire feeding tube 10, directly above the MIG welding torch conductive wire feeding nozzle 6, and directly above the welding area.

[0037] A narrow-gap oscillating laser-MIG hybrid wire filling method for thick-walled components includes the following steps:

[0038] Step 1: According to the working range of the laser-MIG hybrid welding equipment, design and prepare a narrow-gap groove on the base metal 1 to be welded.

[0039] Step 2: Remove the surface oxide layer of the base metal 1 in the area to be welded by mechanical grinding, and then clean it with anhydrous ethanol to ensure that the surface of the base metal to be welded is clean and free of oil.

[0040] Step 3: Through the mechanical installation mechanism, arrange the oscillating narrow-gap MIG welding torch 8, the oscillating laser welding torch 3, and the auxiliary wire feeding tube 10 in sequence along the welding direction, and install the shielding gas nozzle I 7, the shielding gas nozzle II 12, and the upper shielding gas hood 13 behind the auxiliary wire feeding tube 10, directly above the MIG welding torch conductive wire feeding nozzle 6, and directly above the welding area respectively.

[0041] Step 4: Adjust and confirm that the oscillating laser welding torch 3, the auxiliary wire feeding tube 10, and the oscillating narrow-gap MIG welding torch 8 are in the same plane and the welding paths coincide. The laser beam 4 is perpendicular to the welding direction. The auxiliary wire feeding tube 10 forms a 60° angle with the axis of the laser beam 4, the MIG welding torch conductive wire feeding nozzle 6 forms a 30° angle with the axis of the laser beam 4, and the distance between the MIG welding wire and the laser beam 4 is 5 mm.

[0042] Step 5: Set the welding wire, laser, and MIG arc welding parameters to ensure the stable coupling of the hot wire-laser-MIG arc. The welding parameters include welding speed, wire feeding speed, hot wire current, defocus amount, laser power, laser oscillation frequency and amplitude, MIG arc current, voltage, and the dry elongation of the welding wire, the oscillation angle and frequency of the oscillating narrow-gap MIG welding torch.

[0043] Step 6: Determine the starting and ending welding positions, pre-feed gas before welding, turn on the oscillating laser welding torch 3, the auxiliary wire feeding tube 10, and the oscillating narrow-gap MIG welding torch 8. Feed the welding wires on both left and right sides into the welding molten pool synchronously. Move the laser-MIG hybrid welding equipment along the welding direction at the set welding speed. During the welding process, the oscillation of the laser spot cooperates with the oscillation of the narrow-gap MIG welding torch 8 to fully stir the molten pool, promote the discharge of bubbles, and at the same time improve the fusion of the side walls of the narrow-gap groove, obtaining high-quality welds; the welding wires on both sides of the laser beam uniformly fill the molten pool synchronously to avoid weld segregation caused by single-side wire feeding;

[0044] Step 7: Repeat the filling welding until the narrow-gap weld is completely filled. After each layer of welding is completed, introduce the shielding gas for 10 - 15 s to prevent the welding joint from oxidation.

[0045] As Figure 2 shown, in Step 1, a small-angle U-groove can be machined on the welding surface of the specimen to be welded. The root face of the groove is 5 mm, the groove angle is 3°, and the groove radius is 7.5 mm; Figure 3 is the cross-sectional morphology of the narrow-gap weld.

[0046] The following gives a specific implementation example: Oscillating laser-MIG hybrid wire filling welding method for runner made of super martensitic stainless steel:

[0047] 1) Materials: The base metal is super martensitic stainless steel 0Cr13Ni5Mo, and the corresponding welding wire is H13 / 5L;

[0048] 2) Plate thickness: 50 mm;

[0049] 3) Welding wires: MIG welding wire (H13 / 5L, Φ1.2 mm), auxiliary wire feeding heating mechanism (H13 / 5L, Φ1.2 mm);

[0050] 4) Groove design: Small-angle U-groove, the root face of the groove is 5 mm, the groove angle is 3°, and the radius R of the groove is 7.5;

[0051] 5) Grind or clean the workpiece to be welded, and assemble and position the workpiece to be welded after grinding or cleaning. At the same time, considering the influence of welding deformation on the groove width, anti-deformation treatment is required;

[0052] 6) Adjust and confirm the spatial position relationship of the auxiliary-side welding wire, laser, and MIG welding wire. Among them, the distance between the laser and the MIG welding wire is 5 mm, the laser beam is perpendicular to the welding direction, the conductive wire feeding nozzle of the MIG welding torch forms a 30° angle with the laser beam, and the auxiliary wire feeding tube forms a 60° angle with the laser beam;

[0053] 7) Check the operating status of water, electricity, gas, and welding equipment;

[0054] 8) Set the parameters for auxiliary wire feeding, laser, and MIG arc welding. The wire feeding speed of the auxiliary wire feeding mechanism is 4 m / min, and the hot wire current is 50 A; the laser defocus amount is 3 mm, the laser swing amplitude is 3 mm, the frequency is 50 Hz, the welding speed is 0.7 m / min, the welding current is 220 A, and the welding voltage is 25 V; the wire feeding speed of the MIG welding torch is 8 m / min, the laser power is 4 kW, the swing angle is 20°, and the frequency is 3 Hz.

[0055] The swing mode of the swing laser welding torch is circular.

[0056] 9) Turn on the control switch. The laser and the arc act on the surface of the workpiece. The left welding wire is fed into the welding molten pool stably synchronously. At the same time, the gun head moves along the welding direction at the set speed and welds under the condition of a narrow-gap groove. In order to achieve the stability and reliability of the welding quality, the molten pool is stirred by the swing laser to promote the discharge of bubbles and refine the grains. At the same time, the wire feeding ratio of the main and auxiliary wire feeding mechanisms is set to reduce the occurrence of sidewall lack of fusion during the narrow-gap groove welding process. After welding, the mechanical properties of the welded joint and the deposited metal are detected.

[0057] The present invention has the following beneficial effects:

[0058] 1) The deposition efficiency is significantly improved: The double wire feeding collaborative design increases the deposition amount per unit time by 30% - 50%. The single-layer single-pass weldable thickness can reach 3 mm - 5 mm, reducing the number of welding passes compared with the traditional single wire feeding mode.

[0059] 2) The weld quality is optimized: The molten pool stirring effect of the swing laser significantly reduces the porosity, and the lack of fusion defect is completely eliminated; The laser-MIG hybrid welding plus the auxiliary laser wire melting double wire collaborative filling avoids segregation. The yield strength of the deposited metal reaches 1001 MPa, and the 0° impact energy of the welded joint is 169 J, far higher than the performance index and meeting the use requirements.

[0060] 3) The adaptability to narrow gaps is enhanced: The groove width is reduced by more than 50%, saving filling materials and shortening the welding time.

[0061] 4) The heat input is precisely controlled: By independently adjusting the main and auxiliary wire feeding speeds and the laser swing parameters, the control of the heat input of the base material and the heat of wire deposition is realized, reducing the welding thermal deformation.

[0062] 5) Wide process compatibility: By adjusting the laser power, wire feeding ratio, and shielding gas composition, it can adapt to the welding requirements of various materials such as stainless steel, high-strength steel, aluminum alloy, titanium alloy, and nickel-based alloy. The process window is wide and the stability is high.

[0063] The specific embodiments of the present invention have been described above. It should be noted that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various modifications or alterations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A narrow gap swing laser-MIG composite wire welding device for thick-walled components, characterized in that: It includes a laser welding mechanism, a MIG welding mechanism, an auxiliary wire feeding mechanism, a gas protection mechanism, and a mechanical installation mechanism; the MIG welding mechanism, the laser welding mechanism, and the auxiliary wire feeding mechanism are arranged in sequence along the welding direction; the auxiliary wire feeding mechanism includes an auxiliary wire feeding tube, a protective gas nozzle II is arranged behind the auxiliary wire feeding tube, and a protective gas hood is arranged just above the welding area; The axis of the laser beam generated by the laser welding mechanism is perpendicular to the welding direction, and the laser beam moves forward along the welding direction while oscillating laterally in a certain pattern; The swinging narrow gap MIG welding mechanism is located in the same plane as the laser beam and the welding path coincides, and the arc swings left and right periodically; The laser beam and the welding wire focusing point of the auxiliary wire feeding mechanism intersect at one point and act together on the same welding molten pool.

2. The device according to claim 1, characterized in that The laser welding mechanism comprises a laser and a swinging laser welding gun. The power line of the swinging laser welding gun is connected to the power interface of the laser generator, and the swinging laser welding gun generates a laser beam.

3. The device according to claim 1, characterized in that The MIG welding mechanism includes a MIG power supply and a swinging narrow gap MIG welding gun. The positive electrode of the MIG power supply is connected to the swinging narrow gap MIG welding gun, and the negative electrode is connected to the base material to be welded. The swinging narrow gap MIG welding gun is provided with a MIG welding gun conductive wire feeding nozzle.

4. The device according to claim 1, characterized in that The auxiliary wire feeding mechanism includes a bypass hot wire power supply, an auxiliary wire feeding tube and a hot wire joint. The auxiliary hot wire power supply is connected to the auxiliary wire feeding tube through the hot wire joint and has a heating function for the welding wire. The auxiliary wire feeding tube feeds the welding wire into the bottom of the groove.

5. A thick-walled component swing laser-MIG composite wire welding method, characterized in that: The following steps are involved: Step 1: Open a narrow gap groove at the welding part of the base metal to be welded, remove the surface oxide layer of the area to be welded, clean it with anhydrous ethanol until there is no oil stain, and clamp the base metal to be welded; Step 2: Arrange the MIG welding mechanism, the laser welding mechanism, and the auxiliary wire feeding mechanism in sequence along the welding direction, and install corresponding gas protection mechanisms behind the auxiliary wire feeding tube, directly above the conductive wire feeding nozzle of the MIG welding gun, and directly above the welding area; Step 3: Adjust and make the swinging laser welding gun, the auxiliary wire feeding tube and the swinging narrow gap MIG welding gun be in the same plane and the welding paths overlap. The axis of the laser beam generated by the swinging laser welding gun is perpendicular to the welding direction. The auxiliary wire feeding tube and the axis of the laser beam are at an angle of 50° to 70°. The conductive wire feeding nozzle of the MIG welding gun and the axis of the laser beam are at an angle of 15° to 45°. The distance between the MIG welding wire and the laser beam is set to 4mm to 6mm. Step 4: Set the auxiliary wire feeding, laser and MIG arc welding parameters to ensure the stable coupling of hot wire, laser and MIG. The welding parameters include welding speed, wire feeding speed, hot wire current, wire diameter, laser defocus, laser power, laser swing frequency and amplitude, MIG arc current, voltage and dry extension of welding wire, swing angle and frequency of swinging MIG welding gun. Step 5: Determine the start and stop positions of welding, and synchronously start the swinging laser welding gun, auxiliary wire feeding and swinging narrow gap MIG welding gun. Driven by the composite welding system, the welding gun group moves along the welding direction at the set welding speed, and the welding wires on the left and right sides are synchronously and evenly fed into the molten pool. Step 6: After each weld is completed, the interlayer temperature is controlled below 150°C and the filling welding is repeated until the entire narrow gap weld is filled.

6. The method according to claim 5, characterized in that: During the welding process, the shielding gas is argon gas with a purity of 99.999% (mass), and the pre-gas supply and delayed gas supply time before and after welding are 10s to 15s.

7. The method according to claim 5, characterized in that: The welding surfaces of the two parent materials to be welded are processed into a small-angle U-shaped groove, the blunt edge of the groove is 5mm to 8mm, the groove angle is 1° to 5°, and the groove radius is 6mm to 8mm.

8. The method according to claim 5, characterized in that: The thickness of the base material to be welded is 50mm to 250mm, and the material is stainless steel, high-strength steel, aluminum alloy, titanium alloy and nickel-based alloy.

9. The method according to claim 5, characterized in that: During welding, set the welding speed to 0.5m / min~2.0m / min, the auxiliary wire feeding speed to 4m / min~6m / min, the wire feeding speed of the swinging narrow gap MIG welding gun to 5m / min~12m / min, the laser defocus amount to -10mm~10mm, the dry extension length of the auxiliary wire feeding tube welding wire to (10±2)mm, the dry extension length of the swinging MIG welding gun welding wire to (15±2)mm, the bypass hot wire current to 40A~60A, the MIG arc current to 160A~320A, the voltage to 22V~29V, the swing angle of the MIG welding gun to 0°~30°, and the frequency to 0Hz~20Hz.

10. The method according to claim 5, characterized in that: The oscillation modes of the oscillating laser welding gun are circular, infinite, sinusoidal, and linear.

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