Handheld laser-electric arc hybrid welding method suitable for medium plate welding

Abstract

The invention provides a handheld laser-electric arc hybrid welding method suitable for medium-thickness plate welding, which comprises the following steps: arranging a hybrid heat source along a welding seam direction, enabling laser to act on the surface of a workpiece in the front, enabling electric arc to act on the workpiece in the rear in a paraxial manner, and controlling the laser and the electric arc to act on the workpiece synchronously, delay or in advance; adjusting the included angle between the laser beam and the arc electrode and the distance between action points, vertically irradiating the workpiece by the laser or changing the angle within a preset angle range, and meanwhile, setting a transverse swinging parameter of the laser in the vertical direction of the welding seam; the position of a welding focus is adjusted according to the thickness of the medium-thickness plate, the focus is kept below the surface of a workpiece by a preset overfocusing amount, and laser power and arc current are matched and set; a groove is formed in a butt joint of the medium-thickness plate, synchronous wire filling is achieved through a wire feeding structure, and the welding wire size and wire feeding parameters are set; protective gas is sent through double paths, the gas flow is controlled, the welding speed is manually controlled, and handheld welding is completed; the invention is used for solving the problem that the conventional handheld laser welding cannot realize the welding of the medium-thickness plate.

Description

Technical Field

[0001] This invention relates to the field of multi-heat source welding technology, and in particular to a handheld laser-arc hybrid welding method suitable for welding medium and thick plates. Background Technology

[0002] Laser-arc hybrid welding technology provides an advanced welding process that combines the advantages of both laser welding and arc welding. These two methods complement each other in terms of performance. During the welding process, the dual heat sources generate a mutual coupling effect, resulting in a welding process with high speed and stable performance. It exhibits typical synergistic welding effects and has broad application prospects.

[0003] In the field of thick plate welding, traditional gas shielded welding or plasma welding are still the main methods, but their limitations are becoming increasingly apparent. If the number of welding layers is large, the speed is slow, the efficiency is low, and the welding deformation is large. Currently, laser-arc hybrid welding technology and equipment, as well as laser-arc hybrid filler wire welding, are developing rapidly, especially when combined with robots. There is great market interest in thick plate welding, particularly in the welding of special materials or dissimilar materials such as aluminum alloys and titanium alloys. Therefore, developing new processes, methods, and engineering applications for high-power laser-arc hybrid welding and laser-filler wire welding for thick plates has become one of the current new trends. For slightly thinner medium-thick plates, such as plates with a thickness of 3-20mm, the laser output power reaches about 5kW. When welding synchronously with an electric arc, the high laser power causes plasma cloud expansion, leading to welding instability. When combined with an electric arc, it results in excessive waste of laser energy. Furthermore, while such laser-arc hybrid equipment can achieve large-scale production using robotic automated welding equipment, the overall price and maintenance costs are high, and it is not convenient enough.

[0004] In the field of laser welding, handheld laser welding equipment has advantages such as convenient operation, fast welding speed, large welding depth, and good adaptability. Market demand is high, and the technology is developing rapidly. Through wire feeding and oscillating laser design, handheld laser welding has been widely used in the welding of thin plates with large gaps. Compared with arc welding, it has significant advantages in welding deformation and residual stress. To achieve welding of medium and thick plates, the laser power needs to be increased. However, under the action of a strong laser, the molten pool produces pores or spatter, resulting in poor welding quality. Furthermore, the formation of strong plasma inhibits the absorption of strong laser by the workpiece, reducing welding efficiency and shallowing the penetration depth. Moreover, when the laser power of handheld laser welding equipment is too high (>3000W), thermal management and device performance are severely challenged, which also limits the applicability of handheld laser welding equipment for welding medium and thick plates.

[0005] Through research and comparison, it was found that in the field of medium and heavy plate welding, there is currently a lack of a handheld laser-arc hybrid welding method applicable to medium and heavy plate welding. The market needs the creation and implementation of relevant technical methods to solve how to drive and control the welding torch parameters and provide corresponding welding methods. Summary of the Invention

[0006] The present invention aims to provide a handheld laser-arc hybrid welding method suitable for welding medium and thick plates, which solves the problem that conventional handheld laser welding cannot achieve welding of medium and thick plates.

[0007] This invention provides a handheld laser-arc hybrid welding method suitable for welding medium and thick plates, comprising the following steps:

[0008] Step 1: Set up a composite heat source along the weld direction. The laser acts on the workpiece surface in front, and the electric arc is behind in a side-axis manner. The laser and the electric arc are controlled by the hand-held part to act on the workpiece synchronously, delayed or ahead of each other, forming a composite heat source input.

[0009] Step 2: Adjust the angle between the laser beam and the arc electrode and the distance between the points of action. The laser is perpendicular to the workpiece or the angle is changed within the preset angle range. At the same time, set the lateral swing parameters of the laser in the vertical direction of the weld.

[0010] Step 3: Adjust the welding focal point position according to the thickness of the medium-thick plate, keep the focal point below the workpiece surface by the preset over-coking amount, and match and set the laser power and arc current.

[0011] Step 4: Open the bevel for the butt joint of the medium and thick plate, realize synchronous wire feeding through the wire feeding structure, and set the wire size and wire feeding parameters;

[0012] Step 5: Use dual-path shielding gas supply, control the gas flow rate, and manually control the welding speed to complete handheld welding, performing vertical, overhead, or horizontal welding.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] This invention addresses the shortcomings of traditional handheld arc welding, such as shallow penetration and poor weld quality, by optimizing the design of a handheld laser-arc hybrid welding method. It combines the advantages of laser welding, such as deep penetration and minimal deformation, enabling handheld welding of medium-thick plates. Through optimization of parameters such as the welding method, welding angle, and power of the laser and arc, a handheld laser-arc hybrid welding method suitable for medium-thick plates is achieved. This method optimizes and matches multiple welding parameters, resulting in welds with excellent surface finish, free from defects such as workpiece cracks and porosity. The welding effect is improved by 50%, the welding speed is 3-5 times that of simple arc welding, and energy costs are reduced by more than 30%.

[0015] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0018] In the attached diagram:

[0019] Figure 1 This is a schematic flowchart of a handheld laser-arc hybrid welding method suitable for welding medium and thick plates provided by the present invention.

[0020] Figure 2 This is a schematic diagram of the heat source distribution and structural position of a handheld laser-arc hybrid welding method suitable for welding medium and thick plates provided by the present invention;

[0021] Figure 3 This invention provides a handheld laser-arc hybrid welding method suitable for welding medium and thick plates. The diagram shows the welded workpiece forming process.

[0022] Figure 4 This invention provides a handheld laser-arc hybrid welding method suitable for welding medium and thick plates, including a side view of the welded structural workpiece and a laser welding formation view.

[0023] The components are: 1. Laser module; 2. Arc module; 3. Molten pool; 4. Welding wire. Detailed Implementation

[0024] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0025] Example 1:

[0026] Please refer to Figure 1-2 This invention provides a handheld laser-arc hybrid welding method suitable for welding medium and thick plates, comprising the following steps:

[0027] Step 1: Set up a composite heat source along the weld direction. The laser acts on the workpiece surface in front, and the electric arc is behind in a side-axis manner. The laser and the electric arc are controlled by the hand-held part to act on the workpiece synchronously, delayed or ahead of each other, forming a composite heat source input.

[0028] Among them, the laser and electric arc are synchronized, delayed or advanced controlled by the start switch of the handheld part, so as to maintain the stability of the electric arc quality during vertical welding, overhead welding or horizontal welding.

[0029] Specifically, a handheld composite welding torch is used, with laser module 1 and arc module 2 arranged sequentially along the weld seam direction. The laser's point of application is located 0-3mm in front of the arc. The timing relationship between the laser and the arc is controlled by a three-position switch on the welding torch handle for synchronization / delay / lead. For example:

[0030] Synchronous mode: Laser and electric arc act on the workpiece simultaneously, suitable for root pass welding of medium-thick plates of 8-12mm.

[0031] Delayed mode: The laser is triggered 0.1-0.3s in advance, and the arc follows after the initial molten pool 3 is formed. It is suitable for filler welding of 12-20mm thick plates.

[0032] Advanced mode: The electric arc starts 0.1s before the laser, using the electric arc preheating to reduce the laser reflectivity, which is suitable for welding highly reflective materials such as aluminum alloys;

[0033] In this embodiment, the laser pre-positioning design utilizes the deep-penetrating properties of the laser to form a keyhole, and the electric arc then fills the molten pool 3 and improves wettability. The synergistic effect increases the welding speed by more than 3 times. The timing control design can flexibly control the temperature gradient of the molten pool 3 by adjusting the order of laser and electric arc action. For example, the delayed mode reduces arc spatter by laser pre-melting, and the advanced mode reduces the laser energy threshold by electric arc preheating.

[0034] Step 2: Adjust the angle between the laser beam and the arc electrode and the distance between the points of action. The laser is perpendicular to the workpiece or the angle is changed within the preset angle range. At the same time, set the lateral swing parameters of the laser in the vertical direction of the weld.

[0035] In step two, the angle between the laser beam and the arc electrode is adjustable from 30 to 60 degrees, and the distance between the points of action of the two on the workpiece is 0 to 3 mm. The laser irradiates the workpiece perpendicularly or changes the angle within a preset angle range of 30 to 60 degrees. The laser lateral swing range is 0 to 5 mm, the scanning speed is 2 to 5000 mm / s, and the swing frequency is 1 to 10 Hz.

[0036] Specifically, the angle between the laser beam and the arc electrode is preferably set to 45°, and the distance between their action points is preferably 1.5 mm, that is, the laser action point is located 1.5 mm in front of the arc. At this time, the molten pool 3 has the best stability and uniform weld width. The laser transverse oscillation is preferably a sinusoidal oscillation mode, the transverse oscillation range is preferably set to 3 mm, the scanning speed is preferably set to 2000 mm / s, and the oscillation frequency is preferably set to 5 Hz, which can effectively suppress the porosity in the weld center and refine the grains.

[0037] In this embodiment, the 45° angle allows for optimal coupling between laser energy and arc heat input. The 1.5mm spacing avoids excessive compression of the arc by the laser while ensuring that the arc can effectively fill the laser molten pool 3. The 3mm swing range covers the bevel width, the 2000mm / s high-speed scanning reduces local overheating, and the 5Hz frequency matches the oscillation period of the molten pool 3 (100-300Hz), reducing the risk of solidification cracks.

[0038] Step 3: Adjust the welding focal point position according to the thickness of the medium-thick plate, keep the focal point below the workpiece surface by the preset over-coking amount, and match and set the laser power and arc current.

[0039] The over-focusing amount below the workpiece surface is approximately 1 / 5 of the workpiece thickness, which is adjusted according to the laser power or by the welding torch angle; the laser power is 500W-2000W, and the arc welding current is 50-300A, which is matched and set according to the plate thickness, material, and bevel type.

[0040] Specifically, for a 12mm thick stainless steel plate, the focal point is located 2.4mm below the workpiece surface, i.e., 1 / 5 of the plate thickness. The laser power is 1500W and the arc current is 200A. At this point, the penetration depth reaches 10mm and the weld formation is good. If the laser power is increased to 2000W, the over-coking amount is simultaneously adjusted to 3mm 1 / 5 of the plate thickness to avoid excessive penetration depth causing the back side to collapse.

[0041] In this embodiment, an over-coking amount of 1 / 5 of the plate thickness balances the deep melting requirement with the stability of the molten pool 3. The negative defocusing point is inside the workpiece to maximize energy density and improve melting depth. The laser power and arc current are set in a 1:0.13 ratio, such as 1500W laser + 200A arc, to ensure that the total energy density of the composite heat source is within 5×10⁻⁶. 4 W / cm 2 The above meets the requirements for full penetration of medium and heavy plates.

[0042] Step 4: Open the bevel for the butt joint of the medium and thick plate, and realize synchronous wire feeding through the wire feeding structure. Set the size of the welding wire and the wire feeding parameters.

[0043] When the thickness of medium-thick plates is 8mm-20mm, the bevel angle of the butt joint is set to 25-45 degrees, and the interface gap is less than 1mm; the size of welding wire 4 is 1-1.6mm, and double wire feeding is used for special material workpieces to ensure the width of the filler weld.

[0044] Specifically, for 12mm thick Q345 steel butt joints, a V-groove is used, with an angle preferably 30°, a gap preferably 0.8mm, and a blunt edge preferably 1mm, to reduce the amount of filler and avoid incomplete fusion; a 1.2mm diameter welding wire 4 is used, with a wire feeding speed preferably 5-8m / min. For special materials such as nickel-based alloys, a double wire feeding structure is used, with two welding wires 4 converging at a 15° angle at the center of the molten pool 3 to improve filling efficiency;

[0045] In this embodiment, a 30° bevel is set to reduce heat input, and a 0.8mm gap is set to reduce weld shrinkage stress. Combined with the laser oscillation range of 3mm, the bevel width can be completely covered. For special materials, the molten pool 3 is homogenized by feeding two wires in a cross manner, avoiding element segregation caused by a single welding wire 4.

[0046] Step 5: Use dual-path shielding gas supply, control the gas flow rate, and manually control the welding speed to complete handheld welding, performing vertical, overhead, or horizontal welding.

[0047] The dual-path protective gas flow rate is 15-30L / min, one path protects the workpiece from oxidation, and the other path protects the laser beam; the manually controlled welding speed is 1.5-10mm / s, and the angle is controlled at 30-60 degrees during horizontal welding.

[0048] Specifically, the main gas uses 15L / min pure argon gas, which protects the molten pool 3 through the welding torch nozzle; the auxiliary gas uses 10L / min helium gas, which purges the optical path through the side hole of the laser module 1 to prevent plasma from shielding the laser; during horizontal welding, a speed of 3mm / s is used, the angle between the welding torch and the workpiece surface is controlled at 45°, and a small crescent-shaped oscillation amplitude of 2mm is used to prevent the molten pool 3 from sagging.

[0049] In this embodiment, argon is used to protect the molten pool 3 from oxidation, and helium is used to reduce the plasma density in the laser path and improve the laser energy utilization rate. In the horizontal welding control, a dynamic balance is formed by setting a 45° angle and a speed of 3 mm / s to reduce the dwell time of the molten pool 3, avoid the liquid metal from sagging due to gravity, and at the same time, the small oscillation refines the grains.

[0050] In this embodiment, the welded forming state of the structural workpiece is as follows: Figure 3 As shown in the figure, the side profile of the structural workpiece after welding and the state of laser welding are shown in the figure.

[0051] In one embodiment, this method can be applied to scenarios such as shipbuilding, engineering machinery, and new energy, for example:

[0052] In the shipbuilding scenario, for butt welding of 12mm marine steel plates, a delayed mode (laser advance by 0.2s), a 45° laser-arc angle, dual gas supply (argon 15L / min + helium 10L / min), a welding speed of 4mm / s, and a weld penetration of 10mm are adopted to achieve the effect of no porosity and improved impact toughness.

[0053] In engineering machinery applications, the welding of 20mm Q345 steel crane booms employs advanced mode (arc advance by 0.1s), laser oscillation (3mm, 5Hz), and double wire feeding (1.6mm diameter × 2) to increase weld width and improve filling efficiency.

[0054] In the context of new energy manufacturing, the welding of aluminum alloy battery boxes adopts a synchronous mode, an over-coking amount of 1.2mm (1 / 5 of the plate thickness), helium protection (20L / min), a welding speed of 10mm / s, and a penetration depth of 4mm, thereby achieving the effect of improving the tensile strength of the weld.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A handheld laser-arc hybrid welding method suitable for welding medium and thick plates, characterized in that, Includes the following steps: Step 1: Set up a composite heat source along the weld direction. The laser acts on the workpiece surface in front, and the electric arc is behind in a side-axis manner. The laser and the electric arc are controlled by the hand-held part to act on the workpiece synchronously, delayed or ahead of each other, forming a composite heat source input. Step 2: Adjust the angle between the laser beam and the arc electrode and the distance between the points of action. The laser is perpendicular to the workpiece or the angle is changed within the preset angle range. At the same time, set the lateral swing parameters of the laser in the vertical direction of the weld. Step 3: Adjust the welding focal point position according to the thickness of the medium-thick plate, keep the focal point below the workpiece surface by the preset over-coking amount, and match and set the laser power and arc current. Step 4: Open the bevel for the butt joint of the medium and thick plate, realize synchronous wire feeding through the wire feeding structure, and set the wire size and wire feeding parameters; Step 5: Use dual-path shielding gas supply, control the gas flow rate, and manually control the welding speed to complete handheld welding, performing vertical, overhead, or horizontal welding.

2. The handheld laser-arc hybrid welding method suitable for welding medium and thick plates according to claim 1, characterized in that, In step two, the angle between the laser beam and the arc electrode is adjustable from 30 to 60 degrees, and the distance between the points of action of the two on the workpiece is 0 to 3 mm; the laser is used to irradiate the workpiece perpendicularly or to change the angle within a preset angle range of 30 to 60 degrees.

3. The handheld laser-arc hybrid welding method suitable for welding medium and thick plates according to claim 1, characterized in that, In step two, the lateral oscillation range of the laser is 0-5mm, the scanning speed is 2-5000mm / s, and the oscillation frequency is 1-10Hz.

4. The handheld laser-arc hybrid welding method suitable for welding medium and thick plates according to claim 1, characterized in that, In step three, the over-focusing amount below the workpiece surface is 1 / 5 of the workpiece thickness, which can be adjusted according to the laser power or by adjusting the welding torch angle.

5. A handheld laser-arc hybrid welding method suitable for welding medium and thick plates according to claim 1, characterized in that, In step three, the laser power is 500W-2000W, and the arc welding current is 50-300A, which are matched and set according to the plate thickness, material, and bevel type.

6. The handheld laser-arc hybrid welding method suitable for welding medium and thick plates according to claim 1, characterized in that, In step four, when the thickness of the medium-thick plate is 8mm-20mm, the bevel angle of the butt joint is set to 25-45 degrees, and the interface gap is less than 1mm.

7. A handheld laser-arc hybrid welding method suitable for welding medium and thick plates according to claim 1, characterized in that, In step four, the welding wire size is 1-1.6mm. For workpieces made of special materials, double wire feeding is used to ensure the width of the filler weld bead.

8. A handheld laser-arc hybrid welding method suitable for welding medium and thick plates according to claim 1, characterized in that, In step five, the flow rate of the dual-path protective gas is 15-30 L / min, one path protects the workpiece from oxidation, and the other path protects the laser beam.

9. A handheld laser-arc hybrid welding method suitable for welding medium and thick plates according to claim 1, characterized in that, In step five, the manually controlled welding speed is 1.5-10 mm / s, and the angle is controlled at 30-60 degrees during horizontal welding.

10. A handheld laser-arc hybrid welding method suitable for welding medium-thick plates according to claim 1, characterized in that, In step one, the laser and electric arc are synchronized, delayed, or advanced by the start switch on the handheld part, so as to maintain the stability of the electric arc quality during vertical welding, overhead welding, or horizontal welding.

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