A laser double-pendulum filler wire welding method

Abstract

This invention relates to a laser double-oscillating filler wire welding method, belonging to the field of laser welding technology. The technical solution is as follows: during the welding process, the laser implements a double oscillation: the first oscillation is a reciprocating oscillation within the groove driven by the laser head along a direction perpendicular to the welding direction; the second oscillation is a high-speed oscillation of the laser beam driven by the laser head's own galvanometer. During welding, the welding wire is fed in from the front of the laser beam, mounted on the laser head, and oscillates synchronously with the laser head in the first oscillation. Through the above double oscillation, the laser beam melts the base material and welding wire within the groove, forming a molten pool, which, after cooling, forms a weld. The positive effects of this invention are: the combined effect of the two oscillations increases the weld width, meeting the welding requirements of medium and thick plates, and significantly improving welding efficiency; it has strong process adaptability and is suitable for automated welding. Furthermore, this method is insensitive to changes in defocusing amount, has stronger process adaptability, and is more suitable for automated welding applications in practical engineering.

Description

Technical Field

[0001] This invention relates to a laser double-pendulum filler wire welding method, belonging to the field of laser welding technology. Background Technology

[0002] In many industrial sectors such as nuclear power, pressure vessels, aerospace, and automotive manufacturing, tungsten inert gas (TIG) welding is commonly used to achieve high-quality welds and smooth weld surfaces. However, TIG welding suffers from low arc energy density, resulting in slow welding speed and low deposition efficiency, which significantly impacts production efficiency. This is especially true for filler and capping welds, where low current and low speed parameters are often required to ensure uniform weld formation, leading to a significant increase in welding time for thick plates or long welds. Furthermore, in automated welding processes, TIG welding is extremely sensitive to arc length (the distance from the tungsten electrode tip to the surface of the laser molten pool). Fluctuations in arc length can easily cause wire sticking, poor weld formation, or even weld interruption. In actual production, deviations in workpiece size and shape, or tungsten electrode burn-out, often lead to changes in arc length, severely hindering the widespread adoption of automated TIG welding applications.

[0003] Laser welding, as a high-energy beam welding process, boasts high energy density, fast welding speed, and excellent weld quality. However, its extremely small spot diameter results in limited weld width, making it difficult to directly meet the weld width requirements for medium and thick plate welding. To alleviate this problem, laser oscillation welding technology has been developed. For example, Chinese patent application CN202210818196.X discloses "A method for double-oscillation laser welding wire for T-shaped welds in medium and thick plates," where the bidirectional oscillation refers to controlling the laser beam to oscillate at high speed along a specific trajectory (such as a circle, triangle, ∞ shape, C shape, or rectangle) via a galvanometer, while the welding wire oscillates sinusoidally under the control of a wire feeder and robot. Although the above technical solutions can increase the weld width to some extent, the widening capability is still insufficient. When the oscillation amplitude is too large, the small laser spot is difficult to form a uniform laser weld pool, easily leading to defects such as undercut and keyhole porosity, and even causing instability in the welding process. Summary of the Invention

[0004] The purpose of this invention is to provide a laser double-oscillating filler wire welding method. The laser head drives the laser beam to reciprocate within the groove perpendicular to the welding direction. At the same time, the laser beam oscillates at high speed under the drive of the galvanometer. The combined effect of the two oscillations increases the weld width, meets the welding requirements of medium and thick plates, and significantly improves welding efficiency. It has strong process adaptability, is suitable for automated welding, and solves the above-mentioned technical problems existing in the prior art.

[0005] The technical solution of this invention is:

[0006] A laser double-oscillating filler wire welding method includes the following steps: During the welding process, the laser performs double oscillation: the first oscillation is the reciprocating oscillation of the laser beam driven by the laser head along the welding direction within the groove; the second oscillation is the high-speed oscillation of the laser beam driven by the galvanometer of the laser head itself; during the welding process, the welding wire is fed in from the front of the laser beam, the welding wire is installed on the laser head and performs the first oscillation synchronously with the laser head; through the above double oscillation, the laser beam melts the base material and welding wire within the groove, forming a laser molten pool, which forms a weld after cooling.

[0007] Furthermore, the first swing's walking trajectory is the first swing trajectory, the width D1 of the first swing trajectory is 2mm to 14mm, it stops when swinging to both ends of the slope, the stopping time is 0 to 0.8s, and the frequency of the first swing is 0.5Hz to 8Hz.

[0008] Furthermore, the second swing trajectory is a second swing trajectory, which can be of any shape. The swing trajectory range is: the width D2 along the welding direction is 0 to 5 mm, the width D3 perpendicular to the welding direction is 0.5 mm to 5 mm, and D3 ≥ D2; the frequency of the second swing is 30 to 300 Hz.

[0009] Furthermore, the power of the laser beam is 500W to 4000W, the angle α between the laser beam and the vertical direction is 0° to 30°, and the defocusing amount is +10mm to -20mm.

[0010] Furthermore, the angle β between the welding wire and the vertical direction is 30° to 80°, the diameter of the welding wire is 0.8 mm to 1.6 mm, and the wire feeding speed is 0 to 3 m / min.

[0011] Furthermore, the laser molten pool needs to be protected by gas during the welding process. The protective gas is pure Ar, a mixture of Ar and CO2, or pure CO2. The protective gas flow rate is 20L / min to 80L / min, and the welding speed is 150mm / min to 1000mm / min.

[0012] The positive effects of this invention are as follows: By using a laser head to drive the laser beam to reciprocate within the bevel perpendicular to the welding direction, and simultaneously using a galvanometer-driven high-speed trajectory oscillation, the combined effect of these two oscillations increases the weld width, meeting the welding requirements of medium and thick plates, and significantly improving welding efficiency. It exhibits strong process adaptability and is suitable for automated welding. Furthermore, this method is insensitive to changes in defocusing amount, further enhancing its process adaptability and making it more suitable for automated welding applications in practical engineering. Attached Figure Description

[0013] Figure 1 This is a front view illustrating the principle of the invention;

[0014] Figure 2 This is a top view of the principle of the invention;

[0015] Figure 3 This is a side view of the principle of the invention;

[0016] Figure 4 This is an isometric view of the principle of the present invention;

[0017] Figure 5 This is a photograph of the weld surface formation in Embodiment 1 of the present invention;

[0018] Figure 6 This is a macroscopic photograph of the weld cross-section in Embodiment 1 of the present invention;

[0019] Figure 7 This is a photograph of the weld surface formation in Embodiment 2 of the present invention;

[0020] Figure 8 This is a macroscopic photograph of the weld cross-section in Embodiment 2 of the present invention;

[0021] Figure 9 This is a photograph of the weld surface formation in Embodiment 3 of the present invention;

[0022] Figure 10 This is a macroscopic photograph of the weld cross-section in Embodiment 3 of the present invention;

[0023] Figure 11 This is a photograph of the weld surface formation in Embodiment 4 of the present invention;

[0024] Figure 12 This is a macroscopic photograph of the weld cross-section in Embodiment 4 of the present invention;

[0025] In the diagram: 1. Laser beam, 2. Welding wire, 3. Laser molten pool, 4. Weld seam, 5. First oscillation trajectory, 6. Second oscillation trajectory. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] like Figure 1 , 2 As shown in Figures 3 and 4, a double-oscillation laser wire-filling welding method is described. During the welding process, the laser performs a double oscillation: the first oscillation is a reciprocating linear oscillation of the laser beam 1 driven by the laser head along a direction perpendicular to the welding direction within the groove; the second oscillation is a high-speed oscillation of the laser beam 1 driven by the galvanometer of the laser head itself; during the welding process, the welding wire 2 is fed in from the front of the laser beam 1, and the welding wire 2 is mounted on the laser head and performs the first oscillation synchronously with the laser head; through the above double oscillation, the laser beam 1 melts the base material and the welding wire 2 within the groove, forming a laser molten pool 3 together, which forms a weld 4 after cooling.

[0028] In the embodiment: D1 is the width of the first oscillation trajectory 5, D2 is the width of the second oscillation trajectory 6 along the welding direction, D3 is the width of the second oscillation trajectory 6 perpendicular to the welding direction, α is the angle between the laser beam 1 and the vertical direction, and β is the angle between the welding wire 2 and the vertical direction.

[0029] Implementation Case 1

[0030] The workpiece to be welded is a 4mm thick carbon steel plate, made of Q345B material, and welding is performed directly on the surface of the plate.

[0031] The width D1 of the first oscillation trajectory 5 is 4 mm, and it pauses at both ends for 0.1 s. The frequency of the first oscillation is 1.7 Hz. The second oscillation trajectory 6 is O-shaped with a diameter of 2.5 mm, meaning the width D2 along the welding direction and the width D3 perpendicular to the welding direction are both 2.5 mm. The frequency of the second oscillation is 30 Hz. The laser beam 1 has a power of 2500 W, an angle α between the laser beam 1 and the vertical direction of 0°, and a defocusing amount of -15 mm. The welding wire 2 has an angle β between the welding wire and the vertical direction of 70°, a diameter of 1.2 mm, and a wire feed speed of 0.4 m / min. During the welding process, pure CO2 gas is used to protect the laser molten pool 3, with a shielding gas flow rate of 35 L / min and a welding speed of 200 mm / min.

[0032] Welding effect as Figure 5 and Figure 6 As shown.

[0033] Implementation Case 2

[0034] The workpiece to be welded is a 4mm thick carbon steel pipe with a diameter of 89mm and a material of Q345B. Welding is performed directly on the surface of the pipe.

[0035] The width D1 of the first oscillation trajectory 5 is 3mm, and it pauses at both ends for 0.2s. The frequency of the first oscillation is 2.0Hz. The second oscillation trajectory 6 is O-shaped with a diameter of 2.5mm, meaning the width D2 along the welding direction and the width D3 perpendicular to the welding direction are both 2.5mm. The frequency of the second oscillation is 40Hz. The laser beam 1 has a power of 2500W, an angle α of 5° with the vertical direction, and a defocusing amount of -10mm. The welding wire 2 has an angle β of 70° with the vertical direction, a diameter of 1.2mm, and a wire feed speed of 0.8m / min. During welding, a mixture of 80% Ar and 20% CO2 gas is used to protect the laser molten pool 3, with a shielding gas flow rate of 30L / min and a welding speed of 280mm / min.

[0036] Welding effect as Figure 7 and Figure 8 As shown.

[0037] Implementation Case 3

[0038] The workpiece to be welded is a 4mm thick stainless steel plate, material 304. This technical solution is used to perform filler and cover welding on the weld seam after laser welding of the root pass.

[0039] The width D1 of the first oscillation trajectory 5 is 6 mm, and it pauses at both ends for 0.2 s. The frequency of the first oscillation is 2.0 Hz. The second oscillation trajectory 6 is rectangular, with a width D2 of 1 mm along the welding direction and a width D3 of 3 mm perpendicular to the welding direction. The frequency of the second oscillation is 100 Hz. The power of laser beam 1 is 1500 W, the angle α between laser beam 1 and the vertical direction is 0°, and the defocusing amount is 0 mm. The angle β between welding wire 2 and the vertical direction is 60°, the diameter of welding wire 2 is 1.0 mm, and the wire feed speed is 0.2 m / min. During the welding process, pure Ar gas is used to protect the laser molten pool 3, with a shielding gas flow rate of 35 L / min and a welding speed of 300 mm / min.

[0040] Welding effect as Figure 9 and Figure 10 As shown.

[0041] Implementation Case 4

[0042] The workpiece to be welded is a 4mm thick stainless steel plate, material 304. This technical solution is used to perform filler and cover welding on the weld seam after laser welding of the root pass.

[0043] The width D1 of the first oscillation trajectory 5 is 6 mm, and it pauses at both ends for 0.2 s. The frequency of the first oscillation is 2.0 Hz. The second oscillation trajectory 6 is rectangular, with a width D2 of 1 mm along the welding direction and a width D3 of 4 mm perpendicular to the welding direction. The frequency of the second oscillation is 150 Hz. The power of laser beam 1 is 1500 W, the angle α between laser beam 1 and the vertical direction is 0°, and the defocusing amount is -10 mm. The angle β between welding wire 2 and the vertical direction is 60°, the diameter of welding wire 2 is 1.0 mm, and the wire feed speed is 0.5 m / min. During the welding process, pure Ar gas is used to protect the laser molten pool 3, with a shielding gas flow rate of 35 L / min and a welding speed of 400 mm / min.

[0044] Welding effect as Figure 11 and Figure 12 As shown.

Claims

1. A laser double-pendulum filler wire welding method, characterized in that... The process includes the following steps: During the welding process, the laser performs a double oscillation: The first oscillation is the reciprocating oscillation of the laser beam (1) driven by the laser head in the groove along the direction perpendicular to the welding direction; The second oscillation is the high-speed oscillation of the laser beam (1) driven by the laser head's own galvanometer; During the welding process, the welding wire (2) is fed in from the front of the laser beam (1), and the welding wire (2) is installed on the laser head and performs the first oscillation synchronously with the laser head; Through the above double oscillation, the laser beam (1) melts the base material and the welding wire (2) in the groove, forming a laser molten pool (3), which is then cooled to form a weld (4); The travel trajectory of the first oscillation is the first oscillation trajectory (5), the width D1 of the first oscillation trajectory (5) is 2mm to 14mm, and it stops at both ends of the groove for 0 to 0.8s, with a frequency of 0.5Hz to 8Hz; The travel trajectory of the second oscillation is the second oscillation trajectory (6), which is of arbitrary shape, and its oscillation trajectory range is: the width D2 along the welding direction is 0 to 5mm. mm, the width D3 perpendicular to the welding direction is 0.5mm to 5mm, and satisfies D3≥ D2; the frequency of the second oscillation is 30 to 300 Hz.

2. The laser double-pendulum filler wire welding method according to claim 1, characterized in that: The power of the laser beam (1) is 500W to 4000W, the angle α between the laser beam (1) and the vertical direction is 0° to 30°, and the defocusing amount is +10mm to -20mm.

3. The laser double-pendulum filler wire welding method according to claim 2, characterized in that: The angle β between the welding wire (2) and the vertical direction is 30° to 80°, the diameter of the welding wire (2) is 0.8 mm to 1.6 mm, and the wire feeding speed is 0 to 3 m / min.

4. A laser double-pendulum filler wire welding method according to claim 1 or 2, characterized in that: The laser molten pool (3) needs to be protected by gas during the welding process. The protective gas is pure Ar gas, a mixture of Ar gas and CO2 gas or pure CO2 gas. The protective gas flow rate is 20L / min to 80L / min, and the welding speed is 150mm / min to 1000mm / min.

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