Sealing laser welding process of 6063 aluminum tube and welded product

Abstract

This invention discloses a sealing laser welding process and welding product for 6063 aluminum tubes, relating to the field of laser welding technology. The sealing laser welding process for 6063 aluminum tubes provides a main pipe, cap, transition ring, and branch pipes. The sealing laser welding process for 6063 aluminum tubes includes the following steps: pre-welding preparation, first circumferential weld, second circumferential weld, and third circumferential weld. The technical solution provided by this invention reduces the risk of poor sealing due to porosity.

Description

Technical Field

[0001] This invention relates to the field of laser welding technology, and in particular to a sealing laser welding process and welded product for 6063 aluminum tubes. Background Technology

[0002] In aerospace, new energy vehicles, and high-end refrigeration fields, piping systems involving gas or liquid transport have extremely stringent requirements for sealing. These systems often utilize lightweight, high-strength 6063 aluminum alloy pipe fittings and components. To ensure long-term reliable operation, the welded joints between pipe fittings must possess extremely high tightness and sealing reliability, capable of withstanding system operating pressure and preventing media leakage. Currently, inert gas shielded welding (IGAW) is traditionally widely used for welding such aluminum alloy pipe fittings. While this process is widely available and relatively flexible, the high thermal conductivity of 6063 aluminum alloy and the sensitivity of liquid metal to changes in hydrogen solubility, coupled with the high heat input and long molten pool duration of MIG welding, makes it highly susceptible to hydrogen absorption during welding. This hydrogen cannot escape quickly enough due to the rapid solidification of the molten pool, resulting in dispersed pores within the weld and near the weld zone. These pores act as microscopic leakage channels, severely compromising the weld's tightness. Summary of the Invention

[0003] The main objective of this invention is to propose a sealing laser welding process and welding product for 6063 aluminum tubes, aiming to reduce the risk of poor sealing due to porosity.

[0004] To achieve the above objectives, the present invention proposes a sealing laser welding process for 6063 aluminum tubes, providing a main pipe, a cap, a transition ring, and branch pipes. The sealing laser welding process for the 6063 aluminum tubes includes the following steps:

[0005] S1. Pre-welding preparation: Assemble the cap and the transition ring at the two ends of the main pipe, and insert the branch pipe into the interface of the transition ring. S2. First circumferential weld: The main pipe is held and driven to rotate at a constant speed by a rotating chuck, and a laser beam is used to perform laser welding on the circumferential weld between the main pipe and the cap to form the first sealing weld. S3. Second circumferential weld: The main pipe is held and driven to rotate at a constant speed by a rotating chuck, and a laser beam is used to perform laser welding on the circumferential weld between the main pipe and the transition ring to form a second sealing weld. S4. The third circumferential weld is performed by using a rotating chuck to hold and drive the main pipe to rotate at a constant speed, and using a laser beam to perform laser welding on the circumferential weld between the transition ring and the branch pipe to form the third sealing weld.

[0006] In one embodiment, in step S2, welding wire is fed into the weld pool simultaneously; The wire feeding speed is 5 mm / s, the laser welding power is 600W, and the rotational linear speed of the main tube is 150 mm / s.

[0007] In one embodiment, in step S3, welding wire is simultaneously fed into the weld pool; The wire feeding speed is 5 mm / s, the laser welding power is 600W, and the rotational linear speed of the main tube is 150 mm / s.

[0008] In one embodiment, in step S4, welding wire is fed into the weld pool simultaneously; The wire feeding speed is 5 mm / s, the laser welding power is 600W, and the rotational linear speed of the main tube is 150 mm / s.

[0009] In one embodiment, the welding wire is a 4043 aluminum alloy welding wire.

[0010] In one embodiment, in steps S2, S3 and S4, the laser beam is output from a laser welding head, which oscillates periodically along a direction perpendicular to the welding direction during the welding process.

[0011] In one embodiment, the oscillation length of the laser welding head is 1.2 mm and the oscillation frequency is 100 Hz.

[0012] In one embodiment, step S1 further includes: performing surface cleaning treatment on the areas to be welded of the main pipe, the cap, the transition ring, and the branch pipe to remove oxide layers and oil stains.

[0013] In one embodiment, after step S4, step S5 is further included: leakage detection, performing leakage detection on the first sealing weld, the second sealing weld and the third sealing weld.

[0014] The present invention also proposes a welded product obtained by the sealing laser welding process of 6063 aluminum tube as described above, the welded product comprising a main tube, a cap, a transition ring, and a branch tube; The cap and the transition ring are respectively located at both ends of the main pipe, and the branch pipe is inserted into the transition ring.

[0015] In the technical solution of this invention, laser welding is employed, which utilizes extremely high laser energy density, rapid heating and cooling rates, and a very short molten pool duration. This significantly suppresses hydrogen absorption and bubble aggregation time in the 6063 aluminum alloy molten pool, substantially reducing the tendency to generate porosity and thus lowering the risk of poor sealing due to porosity. Furthermore, by rotating the workpiece while keeping the laser head relatively stationary, continuous and uniform welding of the circumferential seam can be achieved. This method is more stable and facilitates maintaining a constant welding speed, ensuring uniform heat input and consistent penetration throughout the weld, avoiding potential quality defects at the arc initiation and termination points, and improving the overall uniformity and reliability of the sealed weld. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 A schematic flowchart of an embodiment of the sealing laser welding process for 6063 aluminum tubes provided by the present invention; Figure 2 This is a structural schematic diagram of an embodiment of the welding product provided by the present invention.

[0018] Explanation of icon numbers: 1000. Welding products; 1. Main pipe; 2. Cap; 3. Transition ring; 4. Branch pipe.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] This invention proposes a sealing laser welding process for 6063 aluminum tubes.

[0024] Please see Figure 1 In one embodiment of the present invention, a main pipe 1, a cap 2, a transition ring 3, and a branch pipe 4 are provided. The sealing laser welding process of the 6063 aluminum pipe includes the following steps: S1. Pre-welding preparation: Assemble the cap 2 and transition ring 3 at the two ends of the main pipe 1 respectively, and insert the branch pipe 4 into the interface of the transition ring 3. S2. First circumferential weld: The main pipe 1 is held and driven to rotate at a constant speed by a rotating chuck, and a laser beam is used to perform laser welding on the circumferential weld between the main pipe 1 and the cap 2 to form the first sealing weld. S3. Second circumferential weld: The main pipe 1 is held and driven to rotate at a constant speed by a rotating chuck, and a laser beam is used to perform laser welding on the circumferential weld between the main pipe 1 and the transition ring 3 to form the second sealing weld. S4. The third circumferential weld is performed by using a rotating chuck to hold and drive the main pipe 1 to rotate at a constant speed, and using a laser beam to perform laser welding on the circumferential weld between the transition ring 3 and the branch pipe 4 to form the third sealing weld.

[0025] Before welding, provide clean 6063 aluminum alloy main pipe 1, cap 2, transition ring 3, and branch pipe 4. During assembly, press or sleeve the cap 2 and transition ring 3 onto the openings at both ends of the main pipe 1 to ensure tight contact between the mating surfaces. Then, insert the branch pipe 4 into the interface of the transition ring 3.

[0026] The assembled components are clamped onto the rotating chuck, ensuring the axis of the main pipe 1 is coaxial with the rotating shaft. The spatial position of the laser welding head is adjusted so that its output laser beam is precisely focused on the circumferential seam between the main pipe 1 and the cap 2. The welding program is initiated, and the rotating chuck drives the component to rotate uniformly around its axis. Simultaneously, the laser emits light, and the laser beam welds the seam around the entire circumference. During this process, the laser beam acts as a heat source, with highly concentrated energy, rapidly melting the local metal and forming a narrow and deep molten pool, which then solidifies quickly, thus forming a continuous and uniform first sealing weld between the main pipe 1 and the cap 2.

[0027] After the first weld is completed, the component remains clamped on the rotating chuck. Adjust the position of the laser welding head (or adjust the component's orientation using a positioner) to refocus the laser beam onto the mating seam between the main pipe 1 and the transition ring 3. Maintaining the same rotation speed, start the laser to weld, forming the second sealing weld, which securely seals the main pipe 1 and the transition ring 3 together.

[0028] Finally, the laser beam is positioned at the mating seam between transition ring 3 and branch pipe 4. Laser ring welding is then performed while the component rotates at a constant speed to form a third sealing weld, thus completing the sealed connection between branch pipe 4 and the entire component.

[0029] Throughout the welding process, it is preferable to use inert gas to provide coaxial or side-blowing protection for the weld pool to prevent the high-temperature metal from reacting with the air. In the technical solution of this invention, laser welding is employed, which utilizes extremely high laser energy density, rapid heating and cooling rates, and a very short molten pool duration. This significantly suppresses hydrogen absorption and bubble aggregation time in the 6063 aluminum alloy molten pool, substantially reducing the tendency to generate porosity and thus lowering the risk of poor sealing due to porosity. Furthermore, by rotating the workpiece while keeping the laser head relatively stationary, continuous and uniform welding of the circumferential seam can be achieved. This method is more stable and facilitates maintaining a constant welding speed, ensuring uniform heat input and consistent penetration throughout the weld, avoiding potential quality defects at the arc initiation and termination points, and improving the overall uniformity and reliability of the sealed weld.

[0030] Specifically, in one embodiment of the present invention, in step S2, welding wire is synchronously fed into the welding pool; wherein the wire feeding speed is 5 mm / s, the laser welding power is 600W, and the rotational linear speed of the main pipe 1 is 150 mm / s. Specifically, while the laser beam melts the base material to form a weld pool, a wire feeding mechanism coaxially or laterally positioned with the laser head continuously and stably feeds the welding wire into the laser action area. The welding wire rapidly melts under laser irradiation, forming a weld pool together with the locally melted base material, and solidifies to form a filler weld.

[0031] The wire feed speed is set to 5 mm / s, optimized for precise matching with the specific laser power and welding speed. Too low a feed speed leads to insufficient filler metal, poor weld formation, and even undercut; too high a speed may result in incomplete wire melting or molten pool buildup, affecting weld surface formation and internal quality. A speed of 5 mm / s ensures that, given a heat input, the wire is fully melted and adequately replenished in the molten pool, bridging potential assembly gaps and adjusting the chemical composition of the weld metal. The laser welding power is set to 600 W, providing sufficient energy for stable deep penetration welding (keyhole effect) while avoiding excessive burn-out, evaporation, or weld collapse due to excessive power. The rotational speed of the main tube 1 is set to 150 mm / s, directly determining the welding speed. With fixed laser power and wire feed speed, a linear speed of 150 mm / s can ensure a balance between heat input and deposition amount, enabling the weld to achieve appropriate penetration depth and width, and achieving an efficient welding cycle.

[0032] Specifically, in one embodiment of the present invention, in step S3, welding wire is simultaneously fed into the welding pool; wherein the wire feeding speed is 5 mm / s, the laser welding power is 600 W, and the rotational linear speed of the main pipe 1 is 150 mm / s. Specifically, while the laser beam melts the base material to form a weld pool, a wire feeding mechanism coaxially or laterally positioned with the laser head continuously and stably feeds the welding wire into the laser action area. The welding wire rapidly melts under laser irradiation, forming a weld pool together with the locally melted base material, and solidifies to form a filler weld.

[0033] The wire feed speed is set to 5 mm / s, optimized for precise matching with the specific laser power and welding speed. Too low a feed speed leads to insufficient filler metal, poor weld formation, and even undercut; too high a speed may result in incomplete wire melting or molten pool buildup, affecting weld surface formation and internal quality. A speed of 5 mm / s ensures that, given a heat input, the wire is fully melted and adequately replenished in the molten pool, bridging potential assembly gaps and adjusting the chemical composition of the weld metal. The laser welding power is set to 600 W, providing sufficient energy for stable deep penetration welding (keyhole effect) while avoiding excessive burn-out, evaporation, or weld collapse due to excessive power. The rotational speed of the main tube 1 is set to 150 mm / s, directly determining the welding speed. With fixed laser power and wire feed speed, a linear speed of 150 mm / s can ensure a balance between heat input and deposition amount, enabling the weld to achieve appropriate penetration depth and width, and achieving an efficient welding cycle.

[0034] Specifically, in one embodiment of the present invention, in step S4, welding wire is synchronously fed into the welding pool; wherein the wire feeding speed is 5 mm / s, the laser welding power is 600W, and the rotational linear speed of the main pipe 1 is 150 mm / s. Specifically, while the laser beam melts the base material to form a weld pool, a wire feeding mechanism coaxially or laterally positioned with the laser head continuously and stably feeds the welding wire into the laser action area. The welding wire rapidly melts under laser irradiation, forming a weld pool together with the locally melted base material, and solidifies to form a filler weld.

[0035] The wire feed speed is set to 5 mm / s, optimized for precise matching with the specific laser power and welding speed. Too low a feed speed leads to insufficient filler metal, poor weld formation, and even undercut; too high a speed may result in incomplete wire melting or molten pool buildup, affecting weld surface formation and internal quality. A speed of 5 mm / s ensures that, given a heat input, the wire is fully melted and adequately replenished in the molten pool, bridging potential assembly gaps and adjusting the chemical composition of the weld metal. The laser welding power is set to 600 W, providing sufficient energy for stable deep penetration welding (keyhole effect) while avoiding excessive burn-out, evaporation, or weld collapse due to excessive power. The rotational speed of the main tube 1 is set to 150 mm / s, directly determining the welding speed. With fixed laser power and wire feed speed, a linear speed of 150 mm / s can ensure a balance between heat input and deposition amount, enabling the weld to achieve appropriate penetration depth and width, and achieving an efficient welding cycle.

[0036] Furthermore, in one embodiment of the present invention, the welding wire is a 4043 aluminum alloy welding wire. The silicon element in the 4043 aluminum alloy welding wire can effectively lower the solidification temperature range of the weld pool and improve the fluidity of the molten metal during solidification. Silicon can form low-melting-point eutectics in the later stages of solidification, which can significantly improve the weld's resistance to solidification cracking. This helps prevent microcracks under welding stress and ensures weld continuity. Moreover, the 4043 aluminum alloy welding wire has a relatively low melting point and good fluidity, allowing it to spread rapidly in the fast-growing molten pool formed by the laser, resulting in a beautiful weld shape, smooth surface, easy to achieve good weld toe transition, and reduced stress concentration points.

[0037] Furthermore, in one embodiment of the present invention, in steps S2, S3, and S4, the laser beam is output from a laser welding head, which periodically oscillates along a direction perpendicular to the welding direction during the welding process. That is, during circumferential welding, the laser beam does not act as a stationary spot on the weld, but is output from a dedicated laser welding head with beam oscillation capabilities. This laser welding head integrates precision optical elements driven by a servo motor or galvanometer system, enabling real-time controllable periodic reciprocating motion of the laser focus within a plane perpendicular to the welding direction (i.e., along the radial or approximately radial direction of the workpiece circumferential weld). The oscillating beam generates a strong stirring effect on the molten pool, effectively breaking up bubbles formed during laser deep penetration welding and greatly promoting their escape. This effectively improves the sealing performance after welding.

[0038] Specifically, in one embodiment of the present invention, the oscillation length of the laser welding head is 1.2 mm, and the oscillation frequency is 100 Hz. The oscillation length of 1.2 mm refers to the total stroke amplitude of the laser focus oscillating perpendicular to the welding direction being 1.2 mm. This means that the maximum distance the focus moves from the center position to one side is 0.6 mm, and the entire scanning width is 1.2 mm. The oscillation frequency of 100 Hz means that the laser focus completes 100 complete reciprocating oscillation cycles per second. This is a relatively high frequency, ensuring that the molten pool is subjected to extremely rapid and intensive stirring. The 1.2 mm oscillation amplitude provides sufficient space for molten pool stirring, while the high frequency of 100 Hz ensures sufficient and immediate stirring. The combination of these two factors maximizes the expulsion of gas while still ensuring sufficient laser energy to maintain the necessary weld penetration, avoiding incomplete penetration due to oscillation, thus achieving a balance between suppressing porosity and ensuring weld penetration.

[0039] Furthermore, in one embodiment of the present invention, step S1 further includes: performing surface cleaning treatment on the areas to be welded of the main pipe 1, cap 2, transition ring 3, and branch pipe 4 to remove oxide layers and oil stains. The areas to be welded refer to the mating end faces, bevels, and adjacent sides of the mating parts. The goal of the surface cleaning treatment is to remove the natural oxide layer and processing oil stains present in this area. After removing the natural oxide layer, the absorption rate of the clean aluminum alloy surface for laser light is significantly improved and stabilized, making the welding process more stable. Removing processing oil stains can reduce the oxygen source of pores, ensuring the tightness of the weld.

[0040] Specifically, in one embodiment of the present invention, after step S4, step S5 is further included: leakage detection, performing leakage detection on the first sealing weld, the second sealing weld, and the third sealing weld. The welded component is placed in an ambient temperature range of -60°C to +90°C, and under an internal gas pressure of 5 MPa for a specified time (e.g., pressure holding for 2 minutes), and no detectable leakage is allowed in any of the welds.

[0041] Please see Figure 2 The present invention also proposes a welded product 1000, which is obtained by the above-mentioned sealing laser welding process of 6063 aluminum tube. The welded product 1000 includes a main pipe 1, a cap 2, a transition ring 3, and a branch pipe 4; the cap 2 and the transition ring 3 are respectively disposed at both ends of the main pipe 1, and the branch pipe 4 is inserted into the transition ring 3 and communicates with the main pipe 1.

[0042] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A sealing laser welding process for 6063 aluminum tubes, characterized in that, The 6063 aluminum tube is provided with a main pipe, cap, transition ring, and branch pipe. The sealing laser welding process includes the following steps: S1. Pre-welding preparation: Assemble the cap and the transition ring at the two ends of the main pipe, and insert the branch pipe into the interface of the transition ring. S2. First circumferential weld: The main pipe is held and driven to rotate at a constant speed by a rotating chuck, and a laser beam is used to perform laser welding on the circumferential weld between the main pipe and the cap to form the first sealing weld. S3. Second circumferential weld: The main pipe is held and driven to rotate at a constant speed by a rotating chuck, and a laser beam is used to perform laser welding on the circumferential weld between the main pipe and the transition ring to form a second sealing weld. S4. The third circumferential weld is performed by using a rotating chuck to hold and drive the main pipe to rotate at a constant speed, and using a laser beam to perform laser welding on the circumferential weld between the transition ring and the branch pipe to form the third sealing weld.

2. The sealing laser welding process for 6063 aluminum tubes as described in claim 1, characterized in that, In step S2, welding wire is simultaneously fed into the molten welding pool; The wire feeding speed is 5 mm / s, the laser welding power is 600W, and the rotational linear speed of the main tube is 150 mm / s.

3. The sealing laser welding process for 6063 aluminum tubes as described in claim 1, characterized in that, In step S3, welding wire is simultaneously fed into the molten welding pool; The wire feeding speed is 5 mm / s, the laser welding power is 600W, and the rotational linear speed of the main tube is 150 mm / s.

4. The sealing laser welding process for 6063 aluminum tubes as described in claim 1, characterized in that, In step S4, welding wire is simultaneously fed into the molten welding pool; The wire feeding speed is 5 mm / s, the laser welding power is 600W, and the rotational linear speed of the main tube is 150 mm / s.

5. The sealing laser welding process for 6063 aluminum tubes as described in any one of claims 2 to 4, characterized in that, The welding wire is a 4043 aluminum alloy welding wire.

6. The sealing laser welding process for 6063 aluminum tubes as described in claim 1, characterized in that, In steps S2, S3 and S4, the laser beam is output from the laser welding head, which oscillates periodically along a direction perpendicular to the welding direction during the welding process.

7. The sealing laser welding process for 6063 aluminum tubes as described in claim 6, characterized in that, The laser welding head has an oscillation length of 1.2 mm and an oscillation frequency of 100 Hz.

8. The sealing laser welding process for 6063 aluminum tubes as described in claim 1, characterized in that, Step S1 further includes: performing surface cleaning treatment on the areas to be welded of the main pipe, the cap, the transition ring, and the branch pipe to remove oxide layers and oil stains.

9. The sealing laser welding process for 6063 aluminum tubes as described in claim 1, characterized in that, After step S4, step S5 is also included: leakage detection, which involves performing leakage detection on the first sealing weld, the second sealing weld, and the third sealing weld.

10. A welding product, characterized in that, The welded product obtained by the sealing laser welding process of 6063 aluminum tube as described in any one of claims 1 to 9 includes a main tube, a cap, a transition ring, and a branch tube; The cap and the transition ring are respectively located at both ends of the main pipe, and the branch pipe is inserted into the transition ring.

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