High reflectivity material laser plasma hybrid welding process

Abstract

The application provides a high-reflection material laser plasma composite welding process, which is configured with a plasma welding machine, a laser exit head and a to-be-welded piece. The plasma welding machine has a plasma welding gun, the plasma welding gun projects a plasma arc to the to-be-welded piece in a substantially vertical posture, the laser exit head provides a laser beam, the laser beam is combined with the plasma arc in a side-axis mode, and the included angle between the laser beam and the plasma arc is alpha, 10°< alpha <= 50°. The high-reflection material is welded by the laser beam and the plasma in a composite mode, the laser beam can compress the plasma arc, thereby improving the energy density of the plasma arc; and the plasma arc can preheat the weld area of the to-be-welded piece, thereby effectively improving the absorption rate of the to-be-welded piece to the laser beam, which is beneficial to lengthening the molten pool, reducing the temperature gradient, and further increasing the stability of the molten pool, and can reduce defects such as welding spatter and pores.

Description

Technical Field

[0001] This invention relates to the field of welding technology for highly reflective materials, and in particular to a laser-plasma composite welding process for highly reflective materials. Background Technology

[0002] When laser welding is used on highly reflective materials such as aluminum and copper, the laser absorption rate is low, the molten pool is unstable, and defects such as spatter and porosity are easily generated. On the other hand, when plasma welding is used on highly reflective materials, the welding efficiency is low and the workpiece deformation is large. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a laser-plasma composite welding process for high reflectivity materials, which can effectively improve welding efficiency and welding quality.

[0004] The embodiments of the present invention are achieved through the following technical solutions: A laser-plasma composite welding process for highly reflective materials includes a plasma welding machine, a laser emitter head, and a workpiece to be welded. The plasma welding machine has a plasma welding torch, which projects a plasma arc onto the workpiece in a substantially vertical position. The laser emitter head provides a laser beam, which is paraaxially composited with the plasma arc. The angle between the laser beam and the plasma arc is α, where 10° < α ≤ 50°.

[0005] According to a preferred embodiment, 30°<α≤50°.

[0006] According to a preferred embodiment, in the vertical direction, the distance between the ejection end of the plasma welding gun and the workpiece to be welded is D1, where 1mm≤D1≤10mm.

[0007] According to a preferred embodiment, in the welding direction, the distance between the laser beam spot projected onto the workpiece and the plasma arc is D2, where 0mm≤D2≤20mm.

[0008] According to a preferred embodiment, when the workpiece to be welded is made of aluminum alloy, the plasma welding machine uses AC welding mode with a welding current of 5A-300A, wherein the cleaning ratio is 10%-20%, the AC bias ratio is 10%-30%, and the polarity frequency is 20Hz-200Hz.

[0009] According to a preferred embodiment, when the workpiece to be welded is made of copper, the plasma welding machine activates the DC welding mode.

[0010] According to a preferred embodiment, the laser beam is a continuous fiber laser, the laser beam welding power is 1kW-12kW, and the welding speed is 10mm / s-50mm / s.

[0011] According to a preferred embodiment, the plasma welding torch is equipped with argon gas, and the flow rate of the ion gas is not greater than 10 L / min.

[0012] According to a preferred embodiment, a protective gas is provided, wherein the protective gas is argon, and the flow rate of the protective gas is not greater than 12 L / min.

[0013] According to a preferred embodiment, the tungsten electrode indentation of the plasma welding torch is 1mm-10mm, and the nozzle orifice diameter is 2.4mm-4.8mm.

[0014] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects: This invention welds highly reflective materials using a combination of laser beam and plasma. The laser beam can compress the plasma arc, thereby increasing the energy density of the plasma arc; while the plasma arc can preheat the weld area of ​​the workpiece to be welded, thus effectively increasing the absorption rate of the workpiece to the laser beam, which is beneficial for lengthening the molten pool, reducing the temperature gradient, and thus increasing the stability of the molten pool, reducing defects such as welding spatter and porosity. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the spatial structure of the plasma welding torch and the laser beam provided in an embodiment of the present invention; Figure 2 A schematic diagram of the structure of the plasma arc and laser spot on the workpiece to be welded, provided in an embodiment of the present invention; Figure 3 A three-dimensional structural schematic diagram of a welding device for performing laser-plasma composite welding process for highly reflective materials, provided in an embodiment of the present invention; Figure 4 This is a metallographic image of the weld seam of the aluminum alloy in an embodiment of the present invention.

[0017] Icons: 1-Plasma welding torch, 11-Plasma arc, 2-Laser beam, 21-Spot, 3-Workpiece to be welded, 4-Molten pool, 5-Laser ejector head. Detailed Implementation

[0018] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0019] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0021] Please refer to Figures 1 to 4 A laser-plasma composite welding process for highly reflective materials, through methods such as... Figure 3 The welding equipment shown performs welding operations. Specifically, it is equipped with a plasma welding machine, a laser emitter head 5, and workpieces 3 to be welded. The plasma welding machine has a plasma welding torch 1, which projects a plasma arc 11 onto the workpieces 3 in a substantially vertical position. The laser emitter head 5 provides a laser beam 2, which is combined with the plasma arc 11 in a paraaxial manner. The angle between the laser beam 2 and the plasma arc 11 is α, where 10°≤α≤50°. It is understood that the workpieces 3 to be welded are made of highly reflective materials, such as aluminum, copper, aluminum alloys, or copper alloys. During operation, two workpieces 3 are joined together, and the molten pool 4 of the composite welding travels along the joint of the two workpieces 3 to form a weld. Welding using a combination of laser beam 2 and plasma can compress the plasma arc 11, thereby increasing the energy density of the plasma arc 11. The plasma arc 11 can preheat the weld area of ​​the workpiece 3 to be welded, thereby effectively increasing the absorption rate of the workpiece 3 to the laser beam 2. This is beneficial for lengthening the molten pool 4, reducing the temperature gradient, and thus increasing the stability of the molten pool 4, which can reduce defects such as welding spatter and porosity.

[0022] In this embodiment, the plasma arc 11 is guided by the laser beam 2 in the welding direction. Specifically, as follows... Figure 1 and Figure 2As shown, in the welding direction, the laser beam 2 projected onto the workpiece 3 by the laser spot 21 coincides with or is downstream of the contact point of the plasma arc 11 on the workpiece 3. It can be understood that, to achieve the effect of laser and plasma hybrid welding, when the laser spot 21 is downstream of the contact point between the plasma arc 11 and the workpiece 3, the laser spot 21 is within the effective heating range of the plasma arc 11 on the workpiece 3, thereby increasing the absorption rate of the laser beam 2 by the workpiece 3. During the welding process, guiding the plasma arc 11 with the laser beam 2 stabilizes the plasma arc 11, resulting in a larger and deeper molten pool 4, and simultaneously achieving a higher weld profile to more effectively fill the joint between the two workpieces 3, thus improving the welding strength.

[0023] In this embodiment, the plasma welding torch 1 is set in a basically vertical position, which helps to ensure the stability of the plasma arc 11 and the continuity of the welding operation during the welding process. Specifically, the laser beam 2 and the plasma arc 11 are combined in a paraaxial manner, with the included angle between the laser beam 2 and the plasma arc 11 being α, where 10°≤α≤50°. The workpiece 3 to be welded is placed horizontally, and the plasma arc 11 is vertically downward, which allows the electric field and gas flow field of the plasma arc 11 to be symmetrically distributed. When the plasma arc 11 and the laser beam 2 act together on the workpiece 3 to be welded, the light pressure and thermal ionization effect generated by the laser beam 2 will be uniformly transmitted along the arc column axis, effectively compressing the plasma arc 11 and significantly increasing the stiffness of the plasma arc 11, which is beneficial to improving the stability of the plasma arc 11 and the weld joint.

[0024] Furthermore, 30°<α≤50°. Within this included angle range, interference between the plasma welding torch 1 and the laser emitter 5 can be avoided, and the plasma arc 11 and the laser beam 2 can form a reasonable heat source coupling area on the surface of the workpiece 3 to be welded. This ensures effective coordination between the two heat sources and avoids excessive overlap or mutual interference of the heat sources.

[0025] Optionally, in the vertical direction, the distance between the ejection end of the plasma welding torch 1 and the workpiece 3 to be welded is D1, where 1mm ≤ D1 ≤ 10mm. In this embodiment, the ejection end of the plasma welding torch 1 refers to the outlet end of the nozzle of the plasma welding torch 1.

[0026] Optionally, in the welding direction, the distance between the laser beam 2 projected onto the workpiece 3 by the laser beam 2 and the plasma arc 11 is D2, where 0mm≤D2≤20mm.

[0027] In this embodiment, the laser beam 2 is a continuous fiber laser, the welding power of the laser beam 2 is 1kW-12kW, and the welding speed is 10mm / s-50mm / s.

[0028] In this embodiment, the plasma welding torch 1 is equipped with argon gas, and the flow rate of the ion gas is no more than 10L / min.

[0029] In this embodiment, a protective gas is provided, which is argon, and the flow rate of the protective gas is no more than 12L / min.

[0030] In this embodiment, the tungsten electrode indentation of the plasma welding torch 1 is 1mm-10mm, and the nozzle orifice diameter is 2.4mm-4.8mm.

[0031] In some embodiments, when the workpiece 3 to be welded is made of aluminum alloy, the plasma welding machine uses AC welding mode with a welding current of 5A-300A, wherein the cleaning ratio is 10%-20%, the AC bias ratio is 10%-30%, and the polarity frequency is 20Hz-200Hz.

[0032] Further, taking the 6061 aluminum alloy workpiece 3 as an example, the plasma welding machine adopts AC mode. The plasma welding torch 1 is perpendicular to the workpiece 3, the angle α between the laser beam 2 and the plasma arc 11 is 40°, the tungsten electrode indentation is 6mm, the nozzle orifice diameter is 4.8mm, and the distance from the nozzle outlet to the workpiece 3 (i.e., the distance between the exit end of the plasma welding torch 1 and the workpiece 3) is D1 = 3mm. The guiding method is that the laser beam 2 guides the plasma arc 11. The power of the laser beam 2 is 1000W, the welding speed is 30mm / s, the heat source distance (i.e., the distance between the laser beam 21 projected onto the workpiece 3 and the plasma arc 11) is D2 = 2mm, the welding current is 130A, the cleaning ratio is 10%, the AC bias ratio is 25%, the polarity frequency is 80Hz, the plasma gas is argon with a flow rate of 2.5L / min, and the shielding gas is argon with a flow rate of 12L / min.

[0033] In some embodiments, when the workpiece 3 to be welded is made of copper, the plasma welding machine activates the DC welding mode.

[0034] Further, taking T2 copper as an example, the plasma welding machine adopts DC mode. The plasma welding torch 1 is perpendicular to the workpiece 3. The angle α between the laser beam 2 and the plasma arc 11 is 40°. The tungsten electrode indentation is 3.2mm, the nozzle orifice diameter is 3.2mm, and the distance from the nozzle outlet to the workpiece 3, i.e., the distance between the outlet of the plasma welding torch 1 and the workpiece 3, is D1 = 3mm. The guiding method is that the laser beam 2 guides the plasma arc 11. The power of the laser beam 2 is 1500W, the welding speed is 15mm / s, the heat source distance, i.e., the distance between the laser spot 21 projected by the laser beam 2 on the workpiece 3 and the plasma arc 11, is D2 = 4mm, the welding current is 200A, the plasma gas is argon with a gas flow rate of 2.5L / min, and the shielding gas is argon with a gas flow rate of 12L / min.

[0035] In this embodiment, preferably, the plasma welding machine is an AC / DC dual-purpose plasma welding machine.

[0036] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A laser-plasma composite welding process for highly reflective materials, characterized in that, The system is equipped with a plasma welding machine, a laser emitter head, and a workpiece to be welded. The plasma welding machine has a plasma welding torch, which projects a plasma arc onto the workpiece in a basically vertical position. The laser emitter head provides a laser beam, which is combined with the plasma arc in a paraaxial manner. The angle between the laser beam and the plasma arc is α, where 10° < α ≤ 50°.

2. The laser-plasma composite welding process for high-reflectivity materials according to claim 1, characterized in that, 30°＜α≤50°。 3. The laser-plasma composite welding process for high-reflectivity materials according to claim 1, characterized in that, In the vertical direction, the distance between the ejection end of the plasma welding gun and the workpiece to be welded is D1, where 1mm≤D1≤10mm.

4. The laser-plasma composite welding process for high-reflectivity materials according to claim 1, characterized in that, In the welding direction, the distance between the laser beam spot projected onto the workpiece and the plasma arc is D2, where 0mm≤D2≤20mm.

5. The laser-plasma composite welding process for highly reflective materials according to claim 1, characterized in that, When the workpiece to be welded is made of aluminum alloy, the plasma welding machine uses AC welding mode with a welding current of 5A-300A, a cleaning ratio of 10%-20%, an AC bias ratio of 10%-30%, and a variable polarity frequency of 20Hz-200Hz.

6. The laser-plasma composite welding process for high-reflectivity materials according to claim 1, characterized in that, When the workpiece to be welded is made of copper, the plasma welding machine switches to DC welding mode.

7. The laser-plasma composite welding process for high-reflectivity materials according to claim 1, characterized in that, The laser beam is a continuous fiber laser, and the welding power of the laser beam is 1kW-12kW, with a welding speed of 10mm / s-50mm / s.

8. The laser-plasma composite welding process for highly reflective materials according to claim 1, characterized in that, The plasma welding torch is equipped with argon gas, and the flow rate of the argon gas is no more than 10 L / min.

9. The laser-plasma composite welding process for high-reflectivity materials according to claim 1, characterized in that, It is equipped with a protective gas, which is argon, and the flow rate of the protective gas is not greater than 12 L / min.

10. The laser-plasma composite welding process for high-reflectivity materials according to claim 1, characterized in that, The tungsten electrode indentation of the plasma welding torch is 1mm-10mm, and the nozzle orifice diameter is 2.4mm-4.8mm.

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