6 series aluminum alloy welding method and device using magnetic field coordinated time-sharing dual-beam scanning

Abstract

This invention relates to the field of laser welding technology, and in particular to a 6-series aluminum alloy welding method and apparatus using magnetic field-coordinated, time-sharing dual-beam scanning. The method comprises: during the welding process, a blue laser beam is used to scan a spiral path along the path to be welded, forming an array of micro-molten pools; after the blue laser beam stops scanning, a preset interval is set, and a near-infrared laser beam concentric with the blue laser beam spot is emitted, welding along a linear path offset by a preset amount from the center line of the micro-molten pool array; during the emission of the near-infrared laser beam, a constant magnetic field perpendicular to the weld surface is applied to the weld surface. This method improves the welding stability and joint consistency of 6-series aluminum alloys, effectively enhancing the welding effect.

Description

Technical Field

[0001] The present invention relates to the technical field of laser welding, and in particular to a 6-series aluminum alloy welding method and device using a magnetic field coordinated time-sharing dual-beam scanning. Background Art

[0002] 6-series aluminum alloys, with their excellent strength-to-weight ratio, corrosion resistance, and formability, are widely used in automotive lightweighting, rail transportation, and construction. Conventional arc welding suffers from uncontrollable heat input, resulting in a 30-40% loss in joint strength and presents challenges such as porosity, cracks, and severe deformation. Single near-infrared laser welding, on the other hand, is generally subject to problems such as easy deformation, difficult oxide film removal, and large porosity, which are particularly pronounced when welding thin sheets less than 2 mm thick.

[0003] Current research on hybrid welding of aluminum alloys using near-infrared and blue lasers is limited to certain aluminum alloy types, lacking exploration of their impact on 6-series aluminum alloys. Because 6-series aluminum alloys have lower melting points and higher thermal conductivity, directly applying welding methods for other aluminum alloys, such as the welding method for 7-series aluminum alloys described in patent CN119566524A, can lead to uncontrolled molten pools in 6-series aluminum alloys, resulting in porosity, thermal deformation, burn-through, and thermal cracking. Therefore, targeted process optimization is necessary.

[0004] In particular, complex curved components made from 6-series aluminum alloys require extremely high-precision welding. Traditional dual-laser welding struggles to precisely control temperature and shape in complex spatial configurations, leading to uneven weld heat input, stress concentration, and even deformation and cracking. Furthermore, pores within the molten pool cannot be effectively removed, severely impacting joint tightness and fatigue performance, reducing welding effectiveness. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problem of poor welding effect of 6 series aluminum alloy in the prior art.

[0006] To solve the above technical problems, the present invention provides a 6-series aluminum alloy welding method using a magnetic field coordinated time-sharing dual-beam scanning method, which utilizes a blue laser beam and a near-infrared laser beam to butt-weld the 6-series aluminum alloy components to be welded, comprising:

[0007] Use a blue laser beam to scan along the path to be welded in a spiral path to form a micro molten pool array;

[0008] After the blue laser beam stops scanning, a preset time interval passes and a near-infrared laser beam concentric with the blue laser beam spot is emitted, and welding is performed along a linear path offset by a preset offset along the center line of the micro-molten pool array; during the emission of the near-infrared laser beam, a constant magnetic field perpendicular to the welding surface is applied to the welding surface.

[0009] Preferably, the power of the blue laser is set to 800 W, the preset scanning speed is 60-90 mm / s, and the pitch of the spiral path is P=0.1T+0.1 mm, where T is the thickness of the 6 series aluminum alloy component to be welded.

[0010] Preferably, the near-infrared laser power is set to 1200W-2000W, the welding speed is 20-50mm / s, and the preset offset between the linear welding path and the center line of the micro-melting pool array is 0.05P, where P is the pitch of the spiral path scanned by the blue laser beam.

[0011] Preferably, the spot diameter of the blue laser beam is set to 400 μm, and the spot diameter of the near-infrared laser beam is set to 25 μm.

[0012] Preferably, after the blue laser beam stops scanning, a near-infrared laser beam concentric with the blue laser beam spot is emitted 2.5-3.0 seconds later.

[0013] Preferably, during the near-infrared laser beam welding process, a constant magnetic field perpendicular to the welding surface is applied to the welding surface, and the magnetic induction intensity of the constant magnetic field is 0.5T.

[0014] Preferably, before butt welding the 6 series aluminum alloy component to be welded, the welding area of ​​the 6 series aluminum alloy component to be welded is ground and polished with 80-grit sandpaper.

[0015] Preferably, during the butt welding process of the 6 series aluminum alloy component to be welded, the shielding gas is turned on and the flow rate of the shielding gas is adjusted to 25 L / min.

[0016] The present invention also provides a 6 series aluminum alloy welding device with magnetic field coordinated time-sharing dual-beam scanning, comprising:

[0017] A blue laser, configured to emit a blue laser beam;

[0018] A near-infrared laser, configured to emit a near-infrared laser beam concentric with the blue laser beam spot;

[0019] The electromagnetic coil is parallel to the welding path and is arranged on both sides of the 6 series aluminum alloy component to be welded, and is used to apply a constant magnetic field perpendicular to the welding surface to the welding surface during the emission of the near-infrared laser beam;

[0020] The galvanometer control module is used to control the blue laser beam to scan along the path to be welded in a spiral path during the welding process to form a micro-melting pool array; and to control the near-infrared laser beam to weld along a linear path offset by a preset offset from the center line of the micro-melting pool array;

[0021] The central control system is used to set the working parameters and working time of the blue laser, near-infrared laser, electromagnetic coil and galvanometer control module.

[0022] Preferably, the central control system includes:

[0023] A path planning unit is used to calculate the paths of the blue laser beam and the near-infrared laser beam, including the pitch of the spiral path scanned by the blue laser beam and the preset offset between the linear path of the near-infrared laser beam welding and the center line of the micro-melting pool array, and send the calculations to the galvanometer control module;

[0024] A parameter setting unit is used to set the power, scanning speed, welding speed and working time of the blue laser and the near-infrared laser, and send them to the blue laser and the near-infrared laser;

[0025] The magnetic field control unit is used to control the electromagnetic coil to generate a magnetic field.

[0026] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0027] The present invention discloses a 6-series aluminum alloy welding method using a magnetic field coordinated time-sharing dual-beam scanning method. First, a blue laser beam is used to pre-treat the surface of the 6-series aluminum alloy component to be welded by high-speed spiral scanning. This spiral scanning path can improve the uniformity of the thermal field, form a regular micro-molten pool array, break the oxide film on the surface of the aluminum alloy, and improve the laser absorption rate, providing a stable melting foundation for the subsequent near-infrared laser main welding. Then, a near-infrared laser beam is used to weld in a linear path, and the linear path of the near-infrared laser beam is offset by a certain distance from the center line of the micro-molten pool array to avoid excessive energy concentration. A constant magnetic field is introduced to enhance the convection of the molten pool and the efficiency of pore escape, thereby reducing the porosity of the weld. By emitting the blue laser beam and the near-infrared laser beam in a time-sharing manner, the present invention avoids the problems of energy superposition leading to local overheating, spattering, increased porosity, and difficulty in accurately controlling heat input during traditional near-infrared and blue light simultaneous emission welding of 6-series aluminum alloys. This improves the welding stability and joint consistency of the 6-series aluminum alloy, effectively improving the welding effect.

[0028] Furthermore, the present invention addresses the proneness to deformation of 6-series aluminum alloy components by dynamically calculating the pitch of the spiral path of the blue laser beam based on the thickness of the 6-series aluminum alloy component being welded. This optimizes heat input distribution, increases the surface absorption efficiency of the near-infrared laser in the subsequent weld area, and reduces energy consumption. To avoid excessive heat input concentration and optimize heat input distribution, the present invention also dynamically calculates a preset offset between the linear path of the near-infrared laser beam welding and the centerline of the micro-molten pool array based on the pitch, achieving optimized energy distribution and stable weld formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0030] Figure 1This is a flow chart of a 6-series aluminum alloy welding method using a magnetic field coordinated time-sharing dual-beam scanning method according to the present invention;

[0031] Figure 2 Schematic diagram of the micro-melting pool array generated by the blue laser beam moving in a spiral path and the path of the near-infrared laser beam deviation;

[0032] Figure 3 This is an example diagram of a complex curved component made of 6 series aluminum alloy;

[0033] Figure 4 is a schematic diagram of the magnetic field;

[0034] Figure 5 This is a comparison diagram of the weld cross section metal phases of single near-infrared laser welding and near-infrared-blue light time-sharing composite welding of the present invention under the condition of a magnetic field, where Figure 5 (a) is a metallographic image of the weld cross section of the near infrared-blue light time-sharing composite welding of the present invention. Figure 5 (b) is a metallographic image of the weld cross section of a single near-infrared laser welding;

[0035] Figure 6 This is a comparison chart of the weld porosity between single near-infrared laser welding and the near-infrared-blue light time-sharing composite welding of the present invention under the condition of a magnetic field;

[0036] Figure 7 This is a comparison of the macroscopic morphology of the weld seams produced by single near-infrared laser welding and near-infrared-blue light time-sharing composite welding of the present invention under the condition of a magnetic field. Figure 7 (a) is the macroscopic morphology of the weld seam produced by near-infrared-blue light time-sharing composite welding of the present invention. Figure 7 (b) is the macroscopic morphology of the weld seam welded by single near-infrared laser welding;

[0037] Figure 8 It is the cross-sectional morphology of the weld after welding of complex curved components, where Figure 8 (a) is the metallographic OM image of the weld cross section after welding of complex curved components. Figure 8 (b) is the cross-sectional grain size diagram;

[0038] Figure 9 This is a comparison chart of the weld porosity after near-infrared-blue light time-sharing composite welding in the presence of a magnetic field and in the absence of a magnetic field;

[0039] Figure 10 It is a schematic diagram of a 6 series aluminum alloy welding device with magnetic field coordinated time-sharing dual-beam scanning according to the present invention. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0041] The blue laser used in near-infrared laser and blue laser hybrid welding technology is efficiently absorbed by aluminum alloys, significantly reducing initial high reflectivity and improving energy efficiency. The near-infrared laser stabilizes the molten pool and increases penetration. The combined effects reduce porosity and cracks, improving weld formation and making it particularly suitable for precision welding of thin plates and highly reflective materials.

[0042] Reference Figure 1 As shown, the present invention provides a 6 series aluminum alloy welding method using a magnetic field coordinated time-sharing dual-beam scanning method, which uses a blue laser beam and a near-infrared laser beam to butt-weld the 6 series aluminum alloy components to be welded, comprising:

[0043] During the welding process, a blue laser beam is used to scan along the path to be welded in a spiral path to form an array of micro molten pools;

[0044] After the blue laser beam stops scanning, a preset time interval passes and a near-infrared laser beam concentric with the blue laser beam spot is emitted, and welding is performed along a linear path offset by a preset offset along the center line of the micro-molten pool array; during the emission of the near-infrared laser beam, a constant magnetic field perpendicular to the welding surface is applied to the welding surface.

[0045] The micro melting pool array generated by the spiral path movement of the blue laser beam and the path diagram of the near-infrared laser beam deviation refer to Figure 2 As shown. 6 series aluminum alloy complex bending member example reference Figure 3 As shown, the welded component is a three-dimensional curved part with a thickness of 2.0 mm and a curvature radius of 100 mm, which is a typical complex spatial curved surface structure. The method of the present invention is applicable to complex curved components with a curvature radius of not less than 5 mm and a plate thickness of 0.8-2 mm.

[0046] The present invention adopts a welding method in which a blue laser beam and a near-infrared laser beam are emitted in a time-sharing manner. This can avoid the problems of local overheating, spattering, increased porosity and difficulty in accurately controlling heat input caused by energy superposition during traditional near-infrared and blue light simultaneous emission welding of aluminum alloys. This is conducive to controlling heat input and improving welding quality.

[0047] Furthermore, the blue laser beam of this invention employs a spiral scanning path, which improves thermal field uniformity, forms a regular array of micro-molten pools, removes the oxide film on the aluminum alloy surface, and enhances laser absorptivity, providing a stable melting foundation for subsequent near-infrared laser main welding. Furthermore, the linear path of the near-infrared laser beam is offset from the centerline of the micro-molten pool array by a certain distance to avoid excessive energy concentration. Combined with laser time-sharing control, this reduces peak heat input, controls weld deformation, and enables low-heat-impact welding of ultra-thin, complex components.

[0048] Furthermore, the present invention introduces a constant magnetic field perpendicular to the welding surface during the near-infrared laser beam welding process, drives convection inside the molten pool through the Lorentz force, accelerates the escape of pores, and controls the solidification structure morphology, thereby reducing the porosity of the weld and improving the joint microstructure.

[0049] The improvements proposed in the present invention include time-sharing emission of the blue laser beam and the near-infrared laser beam, a spiral path of the blue laser beam along the path to be welded, a linear path of the near-infrared laser beam offset by a certain distance from the center line of the micro-molten pool array, and application of a constant magnetic field perpendicular to the welding surface. These improvements are not only suitable for the welding of 6 series aluminum alloys, but also for the welding of all aluminum alloys, and can effectively improve the welding effect.

[0050] In view of the plate properties of 6 series aluminum alloy, the present invention further explores the welding parameters suitable for 6 series aluminum alloy components, specifically including: the pitch of the spiral path of the blue laser beam, the offset of the near-infrared laser beam, the power and scanning speed of the blue laser, and the power and welding speed of the near-infrared laser.

[0051] Preferably, the power of the blue laser is set to 800W, and the preset scanning speed is 60-90mm / s, forming a micro-molten pool array with a diameter of about 50μm and a spacing of 100μm to break the oxide film on the surface of the aluminum alloy and improve the laser absorption rate. Furthermore, in view of the characteristic that 6-series aluminum alloy components are easy to deform, the present invention dynamically calculates the pitch of the spiral path according to the thickness of the 6-series aluminum alloy component to be welded to optimize the heat input distribution. The pitch calculation formula of the spiral path is P=0.1T+0.1mm, where T is the thickness of the 6-series aluminum alloy component to be welded, so as to cover 1.2-1.5 times the width of the welding area, improve the absorption efficiency of the welding area surface to the near-infrared laser, and increase the absorption rate of the near-infrared laser from <10% of the traditional method to more than 35%. Deep penetration welding can be achieved without high power input, and energy consumption is reduced by 30%.

[0052] Preferably, the near-infrared laser power is set to 1200W-2000W, and the welding speed is set to 20-50mm / s. To address the proneness of 6-series aluminum alloy components to deformation, the present invention optimizes heat input distribution to avoid excessive heat concentration. The offset between the linear path of the near-infrared laser beam welding and the centerline of the micro-melting pool array is set to 0.05P, where P is the pitch of the spiral path scanned by the blue laser beam. This optimizes energy distribution and stabilizes weld formation.

[0053] The high-speed scanning of the blue laser in this invention only takes 5%-10% of the total welding time, while the low-speed welding of the near-infrared laser achieves high-quality connections, improving overall efficiency by 40%. Furthermore, the power and welding speed of both the blue and near-infrared lasers are tailored to the low melting point of 6-series aluminum alloy components, balancing penetration depth with heat input to avoid welding defects.

[0054] Preferably, the spot diameter of the blue laser beam is larger than that of the near-infrared laser beam. In this embodiment, the spot diameter of the blue laser beam is set to 400 μm, and the spot diameter of the near-infrared laser beam is set to 25 μm.

[0055] Preferably, after the blue laser beam stops scanning, a near-infrared laser beam concentric with the blue laser beam spot is emitted 2.5-3.0 seconds later to avoid excessive heat input and energy interference when working simultaneously.

[0056] Preferably, during the near-infrared laser beam welding process, a constant magnetic field perpendicular to the welding surface is applied to the welding surface, and the magnetic induction intensity of the constant magnetic field is 0.5T; the magnetic field schematic diagram is shown in FIG. Figure 4 As shown in the figure, the magnetic field acts on the micro-molten pool array, enhancing the convection inside the molten pool through electromagnetic disturbance, promoting the escape of bubbles and refining the microstructure, effectively suppressing the generation of pores and thermal cracks.

[0057] Preferably, before welding, the welding area of ​​the 6 series aluminum alloy component to be welded is polished with 80-grit sandpaper to preliminarily remove the oxide film, and then the component is fixed at multiple points using an adjustable flexible clamp to ensure posture stability during three-dimensional curved surface welding.

[0058] Preferably, during the welding process, the shielding gas is turned on and the shielding gas flow rate is adjusted to 25 L / min.

[0059] After welding, the weld quality was assessed using metallographic analysis. The process involved sectioning the weld along its thickness using a wire-cut electric discharge machine, polishing with 600–5000 grit sandpaper, and etching with 0.5% HF for 40 seconds. Pore area was then quantified using a metallographic microscope and image analysis software. The test results showed that the weld surface of the welded component in the embodiment of the present invention was smooth, free of spatter and undercut; the weld thermal deformation was controlled within 0.1 mm / m; the internal porosity was less than 0.1%, and the weld structure was uniform and well-refined. The tensile strength reached over 85% of the parent material strength, meeting the safety requirements of automotive structures.

[0060] In summary, the 6-series aluminum alloy welding method of the present invention with magnetic field coordinated time-sharing dual-beam scanning first uses a blue laser beam to pre-treat the surface of the 6-series aluminum alloy component to be welded by high-speed spiral scanning. The spiral scanning path can improve the uniformity of the thermal field, form a regular micro-molten pool array, break the oxide film on the surface of the aluminum alloy and improve the laser absorption rate, providing a stable melting basis for the subsequent near-infrared laser main welding; then a near-infrared laser beam is used for welding in a linear path, and the linear path of the near-infrared laser beam is offset by a certain distance from the center line of the micro-molten pool array to avoid excessive energy concentration, and introduce a constant magnetic field to enhance the molten pool convection and pore escape efficiency, thereby reducing the porosity of the weld. The present invention avoids the problems of local overheating, spattering, increased porosity and difficulty in precise control of heat input caused by energy superposition when welding 6-series aluminum alloys with traditional near-infrared and blue light simultaneous emission by time-sharing the blue laser beam and the near-infrared laser beam, thereby improving the welding stability and joint consistency of the 6-series aluminum alloy and effectively improving the welding effect.

[0061] The present invention aims to form a micro-molten pool array through high-speed spiral scanning of blue light to pre-treat the oxide film and avoid excessive heat input caused by too low a welding speed, and to perform main welding along an offset path in combination with a near-infrared laser. At the same time, a magnetic field is introduced during the welding process to regulate the behavior of the molten pool, thereby achieving reduced porosity in the welds of flat or complex curved components, controlled thermal deformation, and stable welding formation.

[0062] The effectiveness of the present invention is verified through multiple experiments below.

[0063] Experiment 1 is a typical planar component welding experiment. The specific steps are as follows:

[0064] S11: Prepare the necessary equipment: a near-infrared laser with a wavelength of 1064 nm and a core diameter of 25 μm; a blue laser with a wavelength of 450 nm and a core diameter of 400 μm; the spots of the near-infrared laser beam and the blue laser beam are concentric.

[0065] S12: Prepare material: 6082 aluminum alloy sheet, 1.0 mm thick.

[0066] S13: Pre-treat the aluminum alloy plate: Use rotating sandpaper with 80-grit sandpaper at a speed of 100 m / h to remove the oxide layer. Removing the oxide layer can reduce defects such as inclusions and pores in the weld and improve joint performance.

[0067] S14: Use a fixture to clamp the two plates together and set the process parameters: set the blue light laser power to 800W, the scanning speed to 80mm / s, the laser swing pitch to 0.2mm, and the swing pattern to a spiral shape; set the near-infrared laser power to 1200W, the welding speed to 30mm / s, and the path offset to 0.01mm.

[0068] S15: Plan the processing path and control the moving path through coordinates: set the length to 100mm.

[0069] S16: The electromagnetic coil applies a vertical constant magnetic field with a magnetic field strength of B=0.5T. The magnetic field is only generated during near-infrared welding.

[0070] S17: Connect the protective gas: adjust the protective gas argon flow rate to 25L / min.

[0071] S18: Metallographic examination: Use an electric spark wire cutting machine to cut the welded joint perpendicular to the plate direction. After cutting, use 600-5000 mesh sandpaper for grinding and polishing. Use 0.5% HF to etch the polished sample for 40 seconds.

[0072] S19: Measurement data: Use a metallographic microscope to measure the crack length, pore area, and grain size to confirm the effect.

[0073] Experimental results refer to Figure 5 、 Figure 6 and Figure 7 shown. Figure 5 The figure is a comparison of the cross-section metal of the weld between single near-infrared laser welding and near-infrared-blue light time-sharing composite welding of the present invention under the condition of magnetic field, wherein Figure 5 (a) is a metallographic diagram of the cross section of the weld produced by near infrared-blue light time-sharing composite welding of the present invention. Figure 5 (b) is a metallographic image of the weld cross section of a single near-infrared laser welding. Figure 6 This is a comparison chart of the weld porosity of single near-infrared laser welding and the near-infrared-blue light time-sharing composite welding of the present invention under the condition of a magnetic field. Figure 7 The figure is a comparison of the macroscopic morphology of the weld seams produced by single near-infrared laser welding and near-infrared-blue light time-sharing composite welding of the present invention under the condition of a magnetic field. Figure 7 (a) is the macroscopic morphology of the weld seam produced by near-infrared-blue light time-sharing composite welding of the present invention. Figure 7(b) shows the macroscopic morphology of the weld seam produced by single near-infrared laser welding. The power of the single near-infrared laser welding was 2000 W. The comparison clearly shows that the weld seam produced by the present invention is smaller in width, exhibits better porosity, exhibits no undercut, and exhibits virtually no spatter.

[0074] Experiment 2 is a welding experiment for complex curved components. The specific steps are as follows:

[0075] S21: Prepare the necessary equipment: a near-infrared laser with a wavelength of 1064 nm and a core diameter of 25 μm; a blue laser with a wavelength of 450 nm and a core diameter of 400 μm; the spots of the near-infrared laser beam and the blue laser beam are concentric.

[0076] S22: Prepare material: 6xxx aluminum alloy complex curved member, 2.0 mm thick.

[0077] S23: Pre-treat the aluminum alloy plate: Use 80-grit sandpaper to remove the oxide layer. Removing the oxide layer can reduce defects such as inclusions and pores in the weld and improve joint performance.

[0078] S24: Use a flexible fixture to clamp the two components together and set the process parameters: set the blue light laser power to 800W, the scanning speed to 80mm / s, the laser swing pitch to 0.3mm, and the swing pattern to a spiral shape; set the near-infrared laser power to 1300W, the welding speed to 35mm / s, and the path offset to 0.015mm.

[0079] S25: Plan the processing path and control the moving path through coordinates: set the length to 100mm.

[0080] S26: The electromagnetic coil applies a constant magnetic field in the vertical direction with a magnetic field strength of B=0.5T. The magnetic field is only generated during near-infrared welding. The electromagnetic coils are installed on both sides.

[0081] S27: Connect the protective gas: adjust the protective gas argon flow rate to 25L / min.

[0082] S28: Metallographic examination: Use a wire-cut electric discharge machine to cut the welded joint perpendicular to the plate. After cutting, use 600-5000 grit sandpaper for grinding and polishing. Use 0.5% HF to etch the polished sample for 40 seconds.

[0083] S29: Measurement data: Use a metallographic microscope to measure the crack length and pore area to confirm the effect.

[0084] Reference for weld cross-section morphology after welding complex curved components Figure 8 As shown, Figure 8 (a) is the metallographic OM image of the weld cross section after welding of complex curved components. Figure 8Figure (b) shows the cross-sectional grain size diagram. The figure shows that the forming quality after the near-infrared-blue light time-sharing composite welding of the present invention is good, with no unfused parts, pores with diameters less than 10 μm, no observed agglomeration, and minimal thermal deformation.

[0085] Experiment 3 is a comparative experiment on welding typical planar components without a magnetic field. The steps are the same as Experiment 1. Under the same components and process parameters, only the magnetic field assistance is eliminated.

[0086] Experimental results refer to Figure 9 As shown, Figure 9 This is a comparison of the porosity of the weld seam after near-infrared-blue light time-sharing hybrid welding in the presence of a magnetic field and in the absence of a magnetic field. The results show that the porosity increases to 0.07% under the absence of a magnetic field.

[0087] Through the above experiments, it can be seen that compared with traditional welding, the present invention realizes the precise matching of laser timing, path trajectory and energy field distribution through the collaborative welding strategy of time-sharing dual beam and magnetic field assistance, which significantly improves the stability and adaptability of the weld; the present invention pre-treats the surface of the component through high-speed spiral scanning of blue laser to form a regular micro-molten pool array, effectively breaks the oxide film, improves the laser absorption efficiency, and provides a stable melting basis for subsequent near-infrared laser main welding; the present invention adopts the near-infrared laser welding path and the blue laser path offset configuration, combined with laser time-sharing control, which reduces the heat input peak, controls the welding deformation, and realizes low-heat-impact welding of ultra-thin complex components; the present invention introduces a constant magnetic field auxiliary mechanism, uses magnetic disturbance to enhance the internal flow of the molten pool and the pore escape path, significantly reduces the weld porosity, and improves the joint microstructure.

[0088] In order to explore the adaptability of near-infrared laser power and welding speed, the pitch of the blue laser spiral path, the offset of the near-infrared laser beam, the blue laser scanning speed and interval time according to the characteristics of 6 series aluminum alloy, this embodiment also conducted relevant comparative experiments.

[0089] Comparative experiment 1 is an experiment to explore the power of near-infrared laser. The specific steps are as follows:

[0090] S31: Prepare the necessary equipment, prepare the materials, and pre-treat the aluminum alloy plate in the same way as in Experiment 1.

[0091] S32: Use a fixture to clamp the two plates together and set the process parameters: set the blue light power to 800W, the laser swing pitch to 0.2mm, the swing pattern to spiral, and the scanning speed to 80mm / s; set the near-infrared laser power to 1000W, 1200W, 1600W, 2000W, and 2200W, set the welding speed to 30 mm / s, and the offset path offset to 0.01mm.

[0092] S33: Plan the processing path and control the moving path through coordinates: set the length to 100mm.

[0093] S34: The electromagnetic coil applies a constant magnetic field in the vertical direction with a magnetic field strength of B=0.5T. The magnetic field is only generated during near-infrared welding.

[0094] S35: Connect the protective gas: adjust the protective gas argon flow rate to 25L / min.

[0095] S36: Metallographic examination: Use an electric spark wire cutting machine to cut the welded joint perpendicular to the plate direction. After cutting, use 600-5000 mesh sandpaper for grinding and polishing. Use 0.5% HF to etch the polished sample for 40 seconds.

[0096] S37: Measurement Data: Use a metallographic microscope to measure the porosity, thermal deformation, and penetration depth of the weld joint. See Table 1 for specific experimental data.

[0097] Table 1. Comparative experimental data of different near-infrared laser powers

[0098]

[0099] According to Table 1, it can be found that when the near-infrared laser power is lower than 1200W, the melting depth is insufficient, while when it is higher than 2000W, the heat input is too large, resulting in deformation. Therefore, the optimal power window of the near-infrared laser is finally obtained to be 1200W-2000W.

[0100] The second comparative experiment is to explore the pitch of the blue laser spiral path. The specific steps are as follows:

[0101] S41: Prepare the necessary equipment and pre-treat the aluminum alloy plate in the same manner as in Experiment 1.

[0102] S42: Prepare materials: 6082 aluminum alloy sheet, thickness 1.5 mm.

[0103] S43: Use a fixture to clamp the two plates together and set the process parameters: set the blue light power to 800W, the scanning speed to 70mm / s, the swing pattern to a spiral shape, the pitch to a fixed pitch of 0.2mm, the adaptive pitch calculated according to the formula P=0.1T+0.1, and the fixed pitch to 0.4mm; set the near-infrared laser power to 1500W, the welding speed to 40 mm / s, and the offset path offset to 0.05mm.

[0104] S44: Plan the processing path and control the moving path through coordinates: set the length to 100mm.

[0105] S45: The electromagnetic coil applies a constant magnetic field in the vertical direction with a magnetic field strength of B=0.5T. The magnetic field is only generated during near-infrared welding.

[0106] S46: Connect the protective gas: adjust the protective gas argon flow rate to 25L / min.

[0107] S47: Metallographic examination: Use an EDM wire cutting machine to cut the welded joint perpendicular to the plate. After cutting, use 600-5000 grit sandpaper for grinding and polishing. Use 0.5% HF to etch the polished sample for 40 seconds.

[0108] S48: Measurement Data: Use a metallographic microscope to measure the porosity, heat-affected zone width, and penetration depth of the weld joint. See Table 2 for specific experimental data.

[0109] Table 2. Comparative experimental data of different pitches

[0110]

[0111] According to Table 2, it can be found that when the pitch is adaptively calculated according to the formula P=0.1T+0.1, the welding quality is good, and too large or too small a pitch will cause defects.

[0112] Comparative experiment three is an experiment to explore the near-infrared laser welding speed. The specific steps are as follows:

[0113] S51: Prepare the necessary equipment and pre-treat the aluminum alloy plate in the same manner as in Experiment 1.

[0114] S52: Prepare material: 6063 aluminum alloy, plate thickness 1.0mm.

[0115] S53: Use a fixture to clamp the two plates together and set the process parameters: set the blue light power to 800W, the oscillation pattern to spiral, the pitch to P=0.2mm, and the scanning speed to 90mm / s; set the near-infrared laser power to 1800W, the welding speed to 15 mm / s, 20 mm / s, 30 mm / s, 50 mm / s, and 60 mm / s, and the offset path offset to 0.01mm.

[0116] S54: Plan the processing path and control the moving path through coordinates: set the length to 100mm.

[0117] S55: The electromagnetic coil applies a constant magnetic field in the vertical direction with a magnetic field strength of B=0.5T. The magnetic field is only generated during near-infrared welding.

[0118] S56: Connect the protective gas: adjust the protective gas argon flow rate to 25L / min.

[0119] S57: Metallographic examination: Use an electric spark wire cutting machine to cut the welded joint perpendicular to the plate direction. After cutting, use 600-5000 grit sandpaper for grinding and polishing. Use 0.5% HF to etch the polished sample for 40 seconds.

[0120] S58: Measurement Data: Use a metallographic microscope to measure the porosity and surface quality of the welded joint. See Table 3 for specific experimental data.

[0121] Table 3. Comparative experimental data of different near-infrared laser welding speeds

[0122]

[0123] According to Table 3, it can be found that too slow near-infrared laser welding speed will lead to overheating, and too fast will lead to incomplete fusion, so the optimal near-infrared laser welding speed is 20-50mm / s.

[0124] Comparative experiment 4 is an experiment to explore the offset of the near-infrared laser beam. The specific steps are as follows:

[0125] S61: Prepare the necessary equipment and pre-treat the aluminum alloy plate in the same manner as in Experiment 1.

[0126] S62: Prepare materials: 6061 aluminum alloy sheet, thickness 1.5 mm.

[0127] S63: Use a fixture to clamp the two plates together and set the process parameters: set the blue light power to 800W, the oscillation pattern to spiral, the pitch to P=0.25mm, and the scanning speed to 60mm / s; set the near-infrared laser power to 2000W, the welding speed to 25mm / s, and the offset path offset to 0mm (complete overlap), 0.0125mm (D=0.05P), and 0.05mm.

[0128] S64: Plan the processing path and control the moving path through coordinates: set the length to 100mm.

[0129] S65: The electromagnetic coil applies a constant magnetic field in the vertical direction with a magnetic field strength of B=0.5T. The magnetic field is only generated during near-infrared welding.

[0130] S66: Connect the protective gas: adjust the protective gas argon flow rate to 25L / min.

[0131] S67: Metallographic examination: Use an EDM wire cutting machine to cut the welded joint perpendicular to the plate. After cutting, use 600-5000 grit sandpaper for grinding and polishing. Use 0.5% HF to etch the polished sample for 40 seconds.

[0132] S68: Measurement Data: Use a metallographic microscope to measure the porosity and surface quality of the welded joint. See Table 4 for specific experimental data.

[0133] Table 4. Comparative experimental data of different near-infrared laser beam offsets

[0134]

[0135] According to Table 4, it can be found that the offset of the near-infrared laser beam follows D=0.05P for the best, and insufficient or excessive offset will deteriorate the weld quality.

[0136] Comparative experiment 5 is an experiment to explore the scanning speed of blue laser. The specific steps are as follows:

[0137] S71: Prepare the necessary equipment and pre-treat the aluminum alloy plate in the same manner as in Experiment 1.

[0138] S72: Prepare material: 6061 aluminum alloy sheet, thickness 1.0 mm.

[0139] S73: Use a fixture to clamp the two plates together and set the process parameters: set the blue light power to 800W, the oscillation pattern to spiral, the pitch to P=0.20mm, and the scanning speeds to 50mm / s, 60mm / s, 70mm / s, 90mm / s, and 100mm / s respectively; set the near-infrared laser power to 1600W, the welding speed to 35mm / s, and the offset path offset to 0.01mm.

[0140] S74: Plan the processing path and control the moving path through coordinates: set the length to 100mm.

[0141] S75: The electromagnetic coil applies a constant magnetic field in the vertical direction with a magnetic field strength of B=0.5T. The magnetic field is only generated during near-infrared welding.

[0142] S76: Connect the protective gas: adjust the protective gas argon flow rate to 25L / min.

[0143] S77: Metallographic examination: Use a wire-cut electric discharge machine to cut the welded joint perpendicular to the plate. After cutting, use 600-5000 grit sandpaper for grinding and polishing. Use 0.5% HF to etch the polished sample for 40 seconds.

[0144] S78: Measurement Data: The porosity of the welded joint was measured using a metallographic microscope. See Table 5 for specific experimental data.

[0145] Table 5. Comparative experimental data of different blue laser welding speeds

[0146]

[0147] According to Table 5, it can be found that a blue laser scanning speed that is too low (<60 mm / s) or too high (>90 m / s) will reduce the pretreatment effect. Therefore, the optimal window of the blue laser scanning speed is 60-90 mm / s.

[0148] Comparative Experiment 6 is an experiment to explore the interval time between the blue laser beam and the near-infrared laser beam. The specific steps are as follows:

[0149] S81: Prepare the necessary equipment, prepare the materials, and pre-treat the aluminum alloy plate in the same way as in Experiment 1.

[0150] S82: Use a fixture to clamp the two plates together and set the process parameters: set the blue light power to 800W, the laser swing pitch to 0.2mm, the swing pattern to spiral, and the scanning speed to 80mm / s; set the near-infrared laser power to 1500W, the welding speed to 30 mm / s, the offset path offset to 0.01mm, and the adjustment interval time to 2.0s, 2.5s, 3.0s, and 3.5s.

[0151] S83: Plan the processing path and control the moving path through coordinates: set the length to 100mm.

[0152] S84: The electromagnetic coil applies a constant magnetic field in the vertical direction with a magnetic field strength of B=0.5T. The magnetic field is only generated during near-infrared welding.

[0153] S85: Connect the protective gas: adjust the protective gas argon flow rate to 25L / min.

[0154] S86: Metallographic examination: Use a wire-cut electric discharge machine to cut the welded joint perpendicular to the plate. After cutting, use 600-5000 grit sandpaper for grinding and polishing. Use 0.5% HF to etch the polished sample for 40 seconds.

[0155] S87: Measurement Data: Use a metallographic microscope to measure the porosity, thermal deformation, and penetration depth of the weld joint. See Table 6 for specific experimental data.

[0156] Table 6. Comparative experimental data of different interval times

[0157]

[0158] According to Table 6, it can be found that the porosity is higher when the interval time is shorter, while when the interval time is longer, not only the porosity increases but also the thermal deformation is aggravated. Therefore, the optimal interval time parameter is 2.5s-3.0s.

[0159] Through optimization of six sets of comparative experiments, the welding parameters of the present invention were finally determined to include: power matching: blue laser 800W + near-infrared laser 1200-2000W; speed coordination: blue laser 60-90m / s + near-infrared laser 20-50mm / s; path formula: blue light pitch P = 0.1T + 0.1; near-infrared laser beam offset D = 0.05P; interval time 2.5-3.0s.

[0160] In response to the lack of path adaptation mechanism and active regulation of molten pool behavior in current traditional laser welding when facing complex spatial components, this invention introduces the "path-laser-magnetic field" triple collaborative control technology, which significantly improves the stability of the welding process and the consistency of the joints. It is particularly suitable for batch welding scenarios of complex aluminum alloy components with high quality and high consistency requirements.

[0161] Reference Figure 10 As shown, based on the above-mentioned magnetic field coordinated time-sharing dual-beam scanning 6 series aluminum alloy welding method, the present invention also provides a magnetic field coordinated time-sharing dual-beam scanning 6 series aluminum alloy welding device, comprising:

[0162] A blue laser, configured to emit a blue laser beam;

[0163] A near-infrared laser, configured to emit a near-infrared laser beam concentric with the blue laser beam spot;

[0164] The electromagnetic coil is parallel to the welding path and is arranged on both sides of the 6 series aluminum alloy sheet or complex curved component to be welded, and is used to apply a constant magnetic field perpendicular to the welding surface to the welding surface during the emission of the near-infrared laser beam;

[0165] The galvanometer control module includes: two reflectors for coaxially emitting the blue laser beam and the near-infrared laser beam by turning each other; a lens for focusing the laser and controlling the blue laser beam to scan along the path to be welded in a spiral path during welding to form a micro-melting pool array; and controlling the near-infrared laser beam to weld along a linear path offset by a preset offset from the center line of the micro-melting pool array.

[0166] The central control system is used to set the working parameters and working time of the blue laser, near-infrared laser, electromagnetic coil and galvanometer control module.

[0167] The central control system includes:

[0168] A path planning unit is used to calculate the paths of the blue laser beam and the near-infrared laser beam, including the pitch of the spiral path scanned by the blue laser beam and the preset offset between the linear path of the near-infrared laser beam welding and the center line of the micro-melting pool array, and send the calculations to the galvanometer control module;

[0169] A parameter setting unit is used to set the power, scanning speed, welding speed and working time of the blue laser and the near-infrared laser, and send them to the blue laser and the near-infrared laser;

[0170] The magnetic field control unit is used to control the electromagnetic coil to generate a magnetic field.

[0171] The wavelength of the blue laser is 450 nm and the core diameter is 400 μm; the wavelength of the near-infrared laser is 1064 nm and the core diameter is 25 μm.

[0172] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A 6-series aluminum alloy welding method using a magnetic field coordinated time-sharing dual-beam scanning method, characterized in that: Using blue laser beam and near-infrared laser beam to weld 6 series aluminum alloy components, including: A blue laser beam is used to scan a spiral path along the path to be welded to form a micro-molten pool array; the power of the blue laser is set to 800W, the preset scanning speed is 60-90mm / s, and the pitch of the spiral path is P = 0.1T + 0.1mm, where T is the thickness of the 6 series aluminum alloy component to be welded; After the blue laser beam stops scanning, a preset time interval is set, and a near-infrared laser beam concentric with the blue laser beam spot is emitted to perform welding along a linear path offset by a preset offset from the center line of the micro-molten pool array; the near-infrared laser power is set to 1200W-2000W, the welding speed is set to 20-50mm / s, and the preset offset between the linear welding path and the center line of the micro-molten pool array is 0.05P, where P is the pitch of the spiral path scanned by the blue laser beam; During the emission of the near-infrared laser beam, a constant magnetic field perpendicular to the welding surface is applied to the welding surface.

2. The 6-series aluminum alloy welding method with magnetic field coordinated time-sharing dual-beam scanning according to claim 1 is characterized in that: The spot diameter of the blue laser beam is set to 400 μm, and the spot diameter of the near-infrared laser beam is set to 25 μm.

3. The 6-series aluminum alloy welding method using magnetic field coordinated time-sharing dual-beam scanning according to claim 1 is characterized in that: After the blue laser beam stops scanning, a near-infrared laser beam concentric with the blue laser beam spot is emitted 2.5–3.0 s later.

4. The 6-series aluminum alloy welding method using magnetic field coordinated time-sharing dual-beam scanning according to claim 1 is characterized in that: During the near-infrared laser beam welding process, a constant magnetic field perpendicular to the welding surface is applied to the welding surface, and the magnetic induction intensity of the constant magnetic field is 0.5T.

5. The 6-series aluminum alloy welding method using magnetic field coordinated time-sharing dual-beam scanning according to claim 1 is characterized in that: Before butt welding the 6 series aluminum alloy components to be welded, the welding area of ​​the 6 series aluminum alloy components to be welded should be polished with 80-grit sandpaper.

6. The method for welding 6 series aluminum alloys with magnetic field coordinated time-sharing dual-beam scanning according to claim 1, characterized in that: During the butt welding process of the 6 series aluminum alloy components to be welded, the shielding gas is connected and the shielding gas flow rate is adjusted to 25L / min.

7. A 6-series aluminum alloy welding device with magnetic field coordinated time-sharing dual-beam scanning, characterized in that: A method for welding 6 series aluminum alloys using a magnetic field coordinated time-sharing dual-beam scanning method as claimed in any one of claims 1 to 6, comprising: A blue laser, configured to emit a blue laser beam; A near-infrared laser, configured to emit a near-infrared laser beam concentric with the blue laser beam spot; The electromagnetic coil is parallel to the welding path and is arranged on both sides of the 6 series aluminum alloy component to be welded, and is used to apply a constant magnetic field perpendicular to the welding surface to the welding surface during the emission of the near-infrared laser beam; The galvanometer control module is used to control the blue laser beam to scan along the path to be welded in a spiral path during the welding process to form a micro-melting pool array; and to control the near-infrared laser beam to weld along a linear path offset by a preset offset from the center line of the micro-melting pool array; The central control system is used to set the operating parameters of the blue laser, near-infrared laser, electromagnetic coil and galvanometer control module.

8. The 6-series aluminum alloy welding device with magnetic field coordinated time-sharing dual-beam scanning according to claim 7 is characterized in that: The central control system includes: A path planning unit is used to calculate the paths of the blue laser beam and the near-infrared laser beam, including the pitch of the spiral path scanned by the blue laser beam and the preset offset between the linear path of the near-infrared laser beam welding and the center line of the micro-melting pool array, and send the calculations to the galvanometer control module; A parameter setting unit is used to set the power, scanning speed, welding speed and working time of the blue laser and the near-infrared laser, and send them to the blue laser and the near-infrared laser; The magnetic field control unit is used to control the electromagnetic coil to generate a magnetic field.

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