A heterogeneous material oscillation laser welding method based on synchronous electromagnetic regulation

Abstract

The present application belongs to the field of laser welding of dissimilar materials, and discloses a method for oscillating laser welding of dissimilar materials based on synchronous electromagnetic control, comprising the following steps: according to the shape and size of two dissimilar material welding test plates, determining the clamping mode of the two welding test plates, and clamping them on a welding workbench after cleaning their surfaces; arranging an oscillating laser head, a protective gas nozzle and an electromagnet above the welding test plates, and arranging an alternating electromagnetic coil below the welding test plates, determining the oscillating path and oscillating parameters of the laser beam according to the welding seam width and mechanical property requirements; determining appropriate welding process parameters and electromagnetic parameters in combination with the material and thickness of the welding test plates; performing synchronous electromagnetic control oscillating laser welding according to the set oscillating path of the laser beam until the welding of the two welding test plates is completed. The present application can suppress defects such as hump, pores and asymmetric welds, and realize high-quality welding of dissimilar material composite components.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of laser welding method of oscillation of different materials based on synchronous electromagnetic regulation, belong to different material laser welding field. BACKGROUND

[0002] With the rapid development of modern manufacturing, different material composite components have been widely used in aerospace, rail transportation, petrochemical industry and other fields. Laser welding technology has the advantages of high energy density, fast welding speed, small heat input and small welding deformation, and shows good potential in the manufacturing of different material composite components. Using conventional laser welding method to process different material composite components, it is easy to produce hump, porosity and asymmetric weld defects, and it is difficult to meet the service performance requirements. Oscillating laser welding technology can improve the forming quality of weld by periodically oscillating the laser beam to stir the molten pool and provide good conditions for the escape of bubbles in the molten pool. Electromagnetic auxiliary laser welding technology can improve the flow pattern of molten metal in the molten pool by inducing Lorentz force in the molten pool, and can suppress hump and porosity defects. At present, single stable magnetic field is mainly used to improve the quality of laser welding of different materials, which has the disadvantages of small magnetic field range and difficult adjustment, and it is difficult to meet the demand of welding quality improvement under different process conditions. Therefore, it is urgent to propose a laser welding method of different materials with high welding quality and convenient regulation. SUMMARY

[0003] In order to suppress defects in the welding process of different materials, the present application proposes a kind of laser welding method of oscillation of different materials based on synchronous electromagnetic regulation, improves the stability of the small hole in the molten pool during welding, suppresses hump, porosity and asymmetric weld defects, and further improves the forming quality of different material weld and the mechanical properties of welded joint.

[0004] The technical scheme of the present application is as follows: a kind of laser welding method of oscillation of different materials based on synchronous electromagnetic regulation, comprising the following steps:

[0005] (1) according to the shape and size of two different material welding test plates, determine the clamping mode of two welding test plates, clean the surface of the test plates and clamp them on the welding workbench with clamps;

[0006] (2) arrange oscillating laser head, protective gas nozzle and electromagnet above the welding test plate, arrange alternating electromagnetic coil below the welding test plate, determine the oscillation path and oscillation parameters of laser beam according to the width of weld and mechanical property requirement;

[0007] (3) determine appropriate welding process parameters and electromagnetic parameters according to the material and thickness of the welding test plate;

[0008] (4) Synchronous electromagnetic regulation oscillation laser welding is performed along the set laser beam oscillation path until the welding of the two welding test plates is completed;

[0009] wherein the welding process parameters include laser power, welding speed and protective gas flow rate; the electromagnetic parameters of the electromagnet are magnetic induction intensity; the electromagnetic parameters of the alternating electromagnetic coil include magnetic field frequency, magnetic induction intensity and coil turns;

[0010] In the step (2), the electromagnet above the welding test plate generates a stable magnetic field, the electromagnet moves synchronously with the oscillation laser head along the welding direction, the two electromagnets are symmetrically distributed about the butt joint plane of the welding test plate, the alternating electromagnetic coil below the welding test plate generates an alternating magnetic field, the alternating electromagnetic coil moves synchronously with the oscillation laser head along the welding direction; the height of the oscillation laser head above the welding test plate is adjusted to obtain a suitable defocusing amount; the energy distribution in the oscillation laser welding molten pool can be adjusted by adjusting the lateral offset distance W1 of the central axis of the oscillation laser head, and the asymmetric defects of the weld caused by the difference in thermal physical properties of the dissimilar materials can be suppressed.

[0011] Further, in the step (2), the stable magnetic field can induce Lorentz force in the molten pool, improve the flow pattern of the molten metal in the molten pool, effectively reduce the flow speed of the molten metal at the rear of the molten pool, suppress the hump defect, and also weaken the intensity of the flow of the molten metal at the rear wall of the keyhole, improve the stability of the keyhole in the molten pool, and suppress the pore defect; the alternating magnetic field can induce induced eddy current in the welding test plate, and form an induced heat field in the welding test plate, suppress the collapse of the rear wall of the keyhole, and reduce the formation of the pore defect;

[0012] The spatial distribution of the stable magnetic field can be adjusted by adjusting the lateral distance L1 between the two electromagnets above the welding test plate and the longitudinal distance H1 from the central axis of the electromagnet to the welding test plate; the spatial distribution of the alternating magnetic field can be adjusted by adjusting the lateral offset distance W2 of the central axis of the alternating electromagnetic coil below the welding test plate, the longitudinal distance H2 from the alternating electromagnetic coil to the welding test plate, and the distance L2 between the central axis of the alternating electromagnetic coil and the central axis of the oscillation laser head along the welding direction.

[0013] Further, in the step (2), the laser beam oscillation path and the oscillation parameters can be selected according to the weld width and the mechanical property requirements, wherein the laser beam oscillation path includes a circle, a sine shape and an "∞" shape, and the oscillation parameters include oscillation amplitude and oscillation frequency; the periodic oscillation of the laser beam can produce stirring effect on the molten pool, improve the flow pattern of the molten metal in the molten pool, and form complex eddy current in the molten pool, which provides good conditions for the escape of bubbles in the molten pool, suppresses the pore defect, and improves the forming quality of the weld.

[0014] Further, in step (3), the stable magnetic field generated by the electromagnet induces the Lorentz force in the welding pool, which improves the flow pattern of the molten metal in the pool; wherein the Lorentz force is closely related to the electromagnetic parameters and the welding test plate material; in order to better analyze the influence of the Lorentz force on the pool, the Lorentz force is defined as:

[0015] F = sigma (v x B) x B

[0016] Wherein, sigma is the electrical conductivity of the material, v is the flow rate of the molten metal, and B is the magnetic induction intensity;

[0017] When the alternating current is input in the alternating electromagnetic coil, the alternating magnetic field is formed, so that the induced eddy current is generated in the welding test plate, thereby forming the induced heat field in the welding test plate; under the action of the alternating magnetic field, the heat power density generated by the induced eddy current in the welding test plate is closely related to the welding test plate material and the induced eddy current density; in order to better analyze the influence of the induced eddy current on the welding test plate, the heat power density generated by the induced eddy current is defined as:

[0018]

[0019] Wherein, J is the induced eddy current density;

[0020] Affected by the skin effect, the induced eddy current generated in the welding test plate is mainly concentrated on the lower surface of the welding test plate, and the relationship between the skin depth and the material thickness needs to be considered in the alternating magnetic field; when the skin depth is much smaller than the material thickness, the skin depth can be increased by appropriately reducing the magnetic field frequency, thereby improving the regulation and control effect of the induced heat field on the small hole wall surface stability; the skin depth is defined as:

[0021]

[0022] Wherein, mu is the relative magnetic permeability of the material, mu0 is the vacuum magnetic permeability, f a is the magnetic field frequency.

[0023] Further, in step (4), the protective gas in the welding process is selected as 99.99% high-purity argon, and the protective gas flow is selected according to the process requirements; the specific operation of the welding process is as follows: first, open the water-cooled gate, air pressure gate and protective gas nozzle, second, open the laser, electromagnet and alternating electromagnetic coil power supply, then provide energy to the welding test plate through the oscillating laser beam according to the set oscillating path of the laser beam and the welding process parameters, form a pool and a small hole in the welding test plate, and regulate and control the dynamic behavior and stability of the pool and the small hole according to the set electromagnetic parameters through the stable magnetic field and the alternating magnetic field, finally realize the synchronous electromagnetic regulation and control of the oscillating laser welding process of dissimilar materials, and obtain a welding joint with good weld forming quality.

[0024] The beneficial effects of the present application are as follows:

[0025] 1. The present invention discloses a dissimilar material oscillating laser welding method based on synchronous electromagnetic control, which uses a combination of laser beam oscillation and synchronous electromagnetic control to suppress defects such as humps, porosity and weld asymmetry during the welding process, effectively improving the weld formation quality and joint mechanical properties of dissimilar materials, and achieving high-quality welding of dissimilar material composite components.

[0026] 2. The dissimilar material oscillating laser welding method based on synchronous electromagnetic control described in this invention can improve the dynamic behavior and stability of the molten pool orifice in the welding test plate, improve the welding quality through the control effect of Lorentz force and induced thermal field, and is easy to control, which can meet the high-quality welding requirements of materials such as low carbon steel, stainless steel, aluminum alloy and magnesium alloy. Attached Figure Description

[0027] Figure 1 This is an overall schematic diagram of a dissimilar material oscillation laser welding method based on synchronous electromagnetic control according to the present invention;

[0028] Figure 2 for Figure 1 The main view;

[0029] Figure 3 for Figure 1 The right view;

[0030] In the figure, 1-Welding test plate A, 2-Weld seam, 3-Welding test plate B, 4-Safety gas nozzle, 5-Oscillating laser beam, 6-Oscillating laser head, 7-Electromagnet A, 8-Pinhole, 9-Molten pool, 10-Electromagnet B, 11-Alternating electromagnetic coil. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the present invention—a dissimilar material oscillation laser welding method based on synchronous electromagnetic control—clearer, a detailed description is provided below with reference to the accompanying drawings and specific embodiments. The following embodiments are for illustrative purposes only, and the scope of protection of the present invention includes, but is not limited to, the following embodiments.

[0032] like Figure 1 As shown, this embodiment specifically describes a dissimilar material oscillating laser welding method based on synchronous electromagnetic control. Welding test plate A1 is made of Q235 low-carbon steel, and welding test plate B3 is made of 316L stainless steel, both with a thickness of 5mm. The protective gas blown by the protective gas nozzle 4 is 99.99% high-purity argon. In this embodiment, the welded joint is a butt joint, and the welding method is self-fusion welding without filler metal.

[0033] like Figure 2 and Figure 3As shown, the embodiment adjusts the transverse offset distance W1 of the center axis of the oscillating laser head 6, the transverse distance L1 between the electromagnet A7 and the electromagnet B10, the longitudinal distance H1 from the center axis of the electromagnet A7 and the electromagnet B10 to the welding test plate A1 and the welding test plate B3, the transverse offset distance W2 of the center axis of the alternating electromagnetic coil 11, the longitudinal distance H2 from the alternating electromagnetic coil 11 to the welding test plate A1 and the welding test plate B3, and the distance L2 between the center axis of the alternating electromagnetic coil 11 and the center axis of the oscillating laser head 6 in the welding direction, to adjust the energy distribution and magnetic field distribution in the oscillating laser welding process. The heterogeneous material oscillating laser welding method based on synchronous electromagnetic regulation of the present application is stable and controllable, can effectively suppress defects such as hump, porosity and weld asymmetry, has high weld forming quality, and has good joint mechanical properties.

[0034] The heterogeneous material oscillating laser welding method based on synchronous electromagnetic regulation provided by the embodiment includes the following steps:

[0035] (1) Prepare the required welding test plate A1 and welding test plate B3; in the embodiment, Q235 low carbon steel with a size of 200mmx100mmx5mm is selected as the welding test plate A1, and 316L stainless steel with a size of 200mmx100mmx5mm is selected as the welding test plate B3; the surface of the welding test plate A1 and the welding test plate B3 is cleaned to remove oxides and oil stains on the surface; the welding test plate A1 and the welding test plate B3 are clamped on the welding workbench by a clamp so that the welding test plate A1 and the welding test plate B3 are in close contact;

[0036] (2) Adjust the height of the oscillating laser head 6 so that the defocusing amount is kept at 0mm, adjust the transverse offset distance W1 of the center axis of the oscillating laser head 6 to be 0mm-2mm, set the laser beam oscillation path to be circular, and the oscillation parameters are: oscillation amplitude 0.4mm-1.2mm, oscillation frequency 60Hz-140Hz; adjust the protective gas nozzle 4 so that it is aligned with the position of the oscillating laser welding molten pool 9 and the small hole 8; adjust the transverse distance L1 between the electromagnet A7 and the electromagnet B10 to be 40mm-60mm, the longitudinal distance H1 from the center axis of the electromagnet A7 and the electromagnet B10 to the welding test plate A1 and the welding test plate B3 to be 30mm-50mm, the transverse offset distance W2 of the center axis of the alternating electromagnetic coil 11 to be 0mm-10mm, the longitudinal distance H2 from the alternating electromagnetic coil 11 to the welding test plate A1 and the welding test plate B3 to be 5mm-10mm, and the distance L2 between the center axis of the alternating electromagnetic coil 11 and the center axis of the oscillating laser head 6 in the welding direction to be 0mm-10mm;

[0037] (3) according to the material and thickness of the welding test plate A1 and the welding test plate B3, the suitable welding process parameters and electromagnetic parameters are determined, in the embodiment, the welding process parameters are: laser power 2500W-5000W, welding speed 2.5m / min-10.0m / min, and protective gas flow 10L / min-15L / min; the electromagnetic parameters of the electromagnet A7 and the electromagnet B10 are: magnetic induction intensity 30mT-100mT; the electromagnetic parameters of the alternating electromagnetic coil 11 are: magnetic field frequency 20kHz-80kHz, magnetic induction intensity 30mT-100mT, and coil turns 50turns-100turns;

[0038] (4) according to the set laser beam oscillation path, the synchronous electromagnetic control oscillation laser welding is carried out, the energy is provided to the welding test plate through the oscillation laser beam 5, the molten pool 9 and the small hole 8 are formed in the welding test plate, and the welding of the welding test plate A1 and the welding test plate B3 is completed.

[0039] The purpose, method and content of the present application are further illustrated in detail through the above embodiment. It should be understood that the above is only a specific embodiment of the present application, and is not used to limit the protection scope of the present application. The present application can be applied to other suitable scenes in the welding field through appropriate modification, and any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for oscillating laser welding of dissimilar materials based on synchronized electromagnetic conditioning, characterized by, It comprises the following steps: (1) According to the shape and size of the two dissimilar material welding test plates, determine the clamping method of the two welding test plates, and after cleaning the surface, clamp them on the welding workbench with clamps respectively; (2) Arrange the oscillating laser head, protective gas nozzle and electromagnet above the welding test plate, arrange the alternating electromagnetic coil below the welding test plate, determine the laser beam oscillation path and oscillation parameters according to the weld width and mechanical property requirements; (3) Determine the appropriate welding process parameters and electromagnetic parameters according to the material and thickness of the welding test plate; (4) Perform synchronous electromagnetic control oscillating laser welding according to the set laser beam oscillation path until the welding of the two welding test plates is completed; Wherein, the welding process parameters include laser power, welding speed and protective gas flow rate; the electromagnetic parameter of the electromagnet is magnetic induction intensity; the electromagnetic parameters of the alternating electromagnetic coil include magnetic field frequency, magnetic induction intensity and coil turns; In step (2), the electromagnet above the welding test plate generates a stable magnetic field, the electromagnet moves synchronously with the oscillating laser head along the welding direction, the two electromagnets are symmetrically distributed about the butt joint plane of the welding test plate, the alternating electromagnetic coil below the welding test plate generates an alternating magnetic field, and the alternating electromagnetic coil moves synchronously with the oscillating laser head along the welding direction; adjust the height of the oscillating laser head above the welding test plate to obtain a suitable defocusing amount; by adjusting the transverse offset distance W1 of the central axis of the oscillating laser head, the energy distribution in the oscillating laser welding molten pool can be adjusted, and the weld asymmetry defect caused by the difference in thermal physical properties of dissimilar materials can be suppressed.

2. The method of claim 1, wherein the method is a method of oscillating laser welding of dissimilar materials based on synchronized electromagnetic control, characterized in that, In step (2), the stable magnetic field can induce Lorentz force in the molten pool, improve the flow pattern of the molten metal in the molten pool, effectively reduce the flow velocity of the molten metal at the back of the molten pool, suppress the hump defect, and also weaken the flow intensity of the molten metal at the back wall of the keyhole, improve the stability of the molten pool keyhole, and suppress the pore defect; the alternating magnetic field can induce induced eddy current in the welding test plate, and form an induced heat field in the welding test plate, suppress the collapse of the back wall of the keyhole, and reduce the formation of pore defects; By adjusting the transverse distance L1 between the two electromagnets above the welding test plate and the longitudinal distance H1 from the central axis of the electromagnet to the welding test plate, the spatial distribution of the stable magnetic field can be adjusted; by adjusting the transverse offset distance W2 of the central axis of the alternating electromagnetic coil below the welding test plate, the longitudinal distance H2 from the alternating electromagnetic coil to the welding test plate, and the distance L2 between the central axis of the alternating electromagnetic coil and the central axis of the oscillating laser head along the welding direction, the spatial distribution of the alternating magnetic field can be adjusted.

3. The method of claim 1, wherein the method is a method of oscillating laser welding of dissimilar materials based on synchronized electromagnetic control, characterized in that, In step (2), the laser beam oscillation path and oscillation parameters can be selected according to the weld width and mechanical property requirements, wherein the laser beam oscillation path includes circular, sinusoidal and "∞” shape, and the oscillation parameters include oscillation amplitude and oscillation frequency; the periodic oscillation of the laser beam can produce stirring effect on the molten pool, improve the flow pattern of the molten metal in the molten pool, and form complex eddy current in the molten pool, which provides good conditions for the escape of bubbles in the molten pool, suppresses the pore defect, and improves the forming quality of the weld.

4. The method of claim 1, wherein the method is a method of oscillating laser welding of dissimilar materials based on synchronized electromagnetic control. In step (3), the stable magnetic field generated by the electromagnet induces the Lorentz force inside the welding pool, which improves the flow pattern of the molten metal in the pool; wherein the Lorentz force is closely related to the electromagnetic parameters and the welding test plate material; in order to better analyze the influence of the Lorentz force on the pool, the Lorentz force is defined as: F = σ(v x B) x B Wherein, σ is the electrical conductivity of the material, v is the flow rate of the molten metal, and B is the magnetic induction intensity; When the alternating current is input in the alternating electromagnetic coil, the alternating magnetic field is formed, so that the induced eddy current is generated in the welding test plate, thereby forming the induced heat field in the welding test plate; under the action of the alternating magnetic field, the heat power density generated by the induced eddy current in the welding test plate is closely related to the welding test plate material and the induced eddy current density; in order to better analyze the influence of the induced eddy current on the welding test plate, the heat power density generated by the induced eddy current is defined as: Wherein, J is the induced eddy current density; Affected by the skin effect, the induced eddy current generated in the welding test plate is mainly concentrated on the lower surface of the welding test plate, and the relationship between the skin depth and the material thickness needs to be considered in the alternating magnetic field; when the skin depth is much smaller than the material thickness, the skin depth can be increased by appropriately reducing the magnetic field frequency, thereby improving the regulation and control effect of the induced heat field on the small hole wall surface; the skin depth is defined as: where μ is the relative magnetic permeability of the material, μ0 is the vacuum magnetic permeability, and f is the magnetic field frequency. a is the magnetic field frequency.

5. The method of claim 1, wherein the method is a method of oscillating laser welding of dissimilar materials based on synchronized electromagnetic control, characterized in that, In step (4), the protective gas in the welding process is selected as 99.99% high-purity argon, and the protective gas flow is selected according to the process requirements; the specific operation of the welding process is as follows: first, open the water-cooled gate, air pressure gate and protective gas nozzle, second, open the laser, electromagnet and alternating electromagnetic coil power supply, then provide energy to the welding test plate through the oscillating laser beam according to the set laser beam oscillation path and welding process parameters, form a pool and a small hole in the welding test plate, and regulate and control the dynamic behavior and stability of the pool and the small hole according to the set electromagnetic parameters through the stable magnetic field and the alternating magnetic field, finally realize the synchronous electromagnetic regulation and control of the oscillating laser welding process of dissimilar materials, and obtain a welding joint with good weld forming quality.

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