Laser welding method and apparatus for suppressing weld cracks in aluminum alloys

Abstract

This application discloses a laser welding method and apparatus for suppressing weld cracks in aluminum alloys. The method includes positioning two aluminum alloy parts to form a weld seam extending along a first direction between them; irradiating the weld seam with a Gaussian laser to form a first spot at the weld seam, and moving the first spot relative to the two aluminum alloy parts along the first direction; irradiating the weld seam with a flat-top laser to form a second spot at the weld seam, and moving the second spot relative to the two aluminum alloy parts along the first direction, wherein the second spot and the first spot are sequentially distributed along the first direction; and providing welding wire to the weld seam at the second spot. The laser welding method and apparatus for suppressing weld cracks in aluminum alloys according to the embodiments of this application can solve the problem of weld cracks between aluminum alloy parts.

Description

Technical Field

[0001] This application relates to the field of laser technology, and in particular to a laser welding method and apparatus for suppressing welding cracks in aluminum alloys. Background Technology

[0002] Replacing traditional steel with lightweight aluminum alloys to manufacture high-aluminum car bodies and reduce vehicle weight has become a crucial measure for the automotive industry, especially the new energy vehicle sector, to achieve my country's carbon peaking and carbon neutrality goals. However, during the welding process, the nanoscale strengthening phases in the weld and heat-affected zone lose their precipitation strengthening effect due to coarsening, leading to significant softening of the weld and heat-affected zone. Researchers believe that low-heat-input welding methods are a low-cost solution to this softening problem, making laser welding technology a focus of attention. However, due to the large solidification temperature range and linear expansion coefficient of aluminum alloys, the rapid cooling during laser welding makes them highly susceptible to welding hot cracking defects in the laser weld, significantly reducing the static and dynamic mechanical properties of the weld joint. Summary of the Invention

[0003] This application provides a laser welding method and apparatus for suppressing welding cracks in aluminum alloys, aiming to solve the problem that welding cracks easily appear in the weld seam of aluminum alloy parts when laser welding is used in the prior art.

[0004] This application provides a laser welding method for suppressing welding cracks in aluminum alloys, the method comprising:

[0005] Two aluminum alloy plates are positioned to form a weld seam extending in a first direction between the two aluminum alloy plates. The material of the aluminum alloy plates includes at least one of 6xxx aluminum alloy, 7xxx aluminum alloy and 2xxx aluminum alloy. The thickness of the aluminum alloy plates is greater than or equal to 1 mm and less than or equal to 3 mm.

[0006] The seam to be welded is irradiated by a Gaussian laser to form a first spot at the seam to be welded, and the first spot is moved relative to the two aluminum alloy plates along the first direction. The power of the Gaussian laser is greater than or equal to 1KW and less than or equal to 3KW, and the moving speed of the first spot along the first direction is greater than or equal to 1m / min and less than or equal to 3m / min.

[0007] The weld seam is irradiated by a flat-top laser to form a second spot at the weld seam, and the second spot moves synchronously with the first spot. The second spot and the first spot are distributed sequentially along the first direction. The distance between the second spot and the first spot in the first direction is less than or equal to 3 mm. The power of the flat-top laser is greater than or equal to 0.5 KW and less than or equal to 2 KW.

[0008] Welding wire is provided to the seam to be welded at the second spot. The diameter of the welding wire is greater than or equal to 1 mm and less than or equal to 1.6 mm. The wire feeding speed of the welding wire is greater than or equal to 3 m / min and less than or equal to 6 m / min.

[0009] A protective gas is provided to the area where the first light spot is located, the area where the second light spot is located, and the area between the first light spot and the second light spot, wherein the flow rate of the protective gas is greater than or equal to 10 L / min and less than or equal to 25 L / min.

[0010] This application also provides a laser welding method for suppressing welding cracks in aluminum alloys, the method comprising:

[0011] Position the two aluminum alloy parts so that a weld seam extending in a first direction is formed between the two aluminum alloy parts;

[0012] The seam to be welded is irradiated with a Gaussian laser to form a first spot at the seam, and the first spot is moved relative to the two aluminum alloy parts along the first direction.

[0013] The weld seam is irradiated by a flat-top laser to form a second spot at the weld seam, and the second spot is moved relative to the two aluminum alloy parts along the first direction. The second spot and the first spot are distributed sequentially along the first direction.

[0014] Welding wire is provided to the seam to be welded at the second light spot.

[0015] In some embodiments, the distance between the second light spot and the first light spot in the first direction is less than or equal to 3 mm.

[0016] In some embodiments, the moving speed of the first light spot along the first direction is greater than or equal to 1 m / min and less than or equal to 3 m / min.

[0017] In some embodiments, the moving speed of the first light spot along the first direction is the same as the moving speed of the second light spot along the first direction.

[0018] In some embodiments, the power of the Gaussian laser is greater than or equal to 1KW and less than or equal to 3KW; the power of the flat-top laser is greater than or equal to 0.5KW and less than or equal to 2KW.

[0019] In some embodiments, the diameter of the welding wire is greater than or equal to 1 mm and less than or equal to 1.6 mm; the wire feeding speed of the welding wire is greater than or equal to 3 m / min and less than or equal to 6 m / min.

[0020] This application also provides a laser welding apparatus for suppressing welding cracks in aluminum alloys, comprising:

[0021] A positioning mechanism for supporting and positioning two aluminum alloy parts, wherein a weld seam extending in a first direction is formed between the two aluminum alloy parts;

[0022] The welding mechanism includes a Gaussian laser, a flat-top laser, and a driving assembly. The Gaussian laser is used to emit a Gaussian laser beam towards the weld seam between the two aluminum alloy parts to form a first laser spot at the weld seam. The flat-top laser is used to emit a flat-top laser beam towards the weld seam between the two aluminum alloy parts to form a second laser spot at the weld seam. The second laser spot and the first laser spot are distributed sequentially along a first direction. The driving assembly is connected to the Gaussian laser and the flat-top laser and is used to drive the Gaussian laser and the flat-top laser to move relative to the two aluminum alloy parts 400 along the first direction.

[0023] A wire feeding mechanism is used to provide welding wire to the weld seam at the second spot.

[0024] In some embodiments, the distance between the first light spot and the second light spot is less than or equal to 3 mm.

[0025] In some embodiments, the driving component is used to drive the Gaussian laser and the flat-top laser to move synchronously relative to the two aluminum alloy parts 400 along the first direction.

[0026] The laser welding method for suppressing weld cracks in aluminum alloys provided in this application involves forming a first spot at the weld seam between two aluminum alloy parts using a Gaussian laser, and a second spot at the weld seam using a flat-top laser. The first and second spots are moved along a first direction, and welding wire is provided to the weld seam at the second spot. This allows the substrate at the weld seam to be rapidly melted by the first spot of the Gaussian laser, while the welding wire is simultaneously melted by the second spot of the flat-top laser, filling the weld seam. Utilizing the uniform energy distribution of the second spot of the flat-top laser, the melting efficiency of the welding wire is improved, and the temperature gradient of the molten pool and the solidification cooling rate are reduced, thereby solving the problem of weld cracks between aluminum alloy parts. Attached Figure Description

[0027] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0028] Figure 1 A flowchart illustrating an embodiment of the laser welding method for suppressing welding cracks in aluminum alloys provided in this application;

[0029] Figure 2 A flowchart of another embodiment of the laser welding method for suppressing welding cracks in aluminum alloys provided in this application;

[0030] Figure 3 A schematic diagram of one embodiment of the laser welding apparatus for suppressing welding cracks in aluminum alloys provided in this application;

[0031] Figure 4 Macroscopic morphology of the weld surface and cross-section formed by the first laser welding method is provided in the embodiments of this application;

[0032] Figure 5 Macroscopic morphology images of the weld surface and cross-section formed by the second laser welding method provided in the embodiments of this application;

[0033] Figure 6 Macroscopic morphology images of the weld surface and cross-section formed by the third laser welding method provided in the embodiments of this application;

[0034] Figure 7 The image shows the macroscopic morphology of the weld surface and cross-section formed by the fourth laser welding method, as provided in the embodiments of this application.

[0035] Laser welding device 300; positioning mechanism 310; welding mechanism 320; Gaussian laser 321; Gaussian laser 3211; flat-top laser 322; flat-top laser 3221; wire feeding mechanism 330; welding wire 331; first direction X; aluminum alloy part 400. Detailed Implementation

[0036] The technical solutions of the embodiments of this application 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 this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0037] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0039] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0040] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0041] This application provides a laser welding method and apparatus for suppressing welding cracks in aluminum alloys. These will be described in detail below.

[0042] First, this application provides a laser welding method for suppressing weld cracks in aluminum alloys. The laser welding method for suppressing weld cracks in aluminum alloys includes: positioning two aluminum alloy parts to form a weld seam extending along a first direction between the two parts; irradiating the weld seam with a Gaussian laser to form a first spot at the weld seam, and moving the first spot relative to the two aluminum alloy parts along the first direction; irradiating the weld seam with a flat-top laser to form a second spot at the weld seam, and moving the second spot relative to the two aluminum alloy parts along the first direction, wherein the second spot and the first spot are sequentially distributed along the first direction; and providing welding wire to the weld seam at the second spot.

[0043] The laser welding method for suppressing weld cracks in aluminum alloys provided in this application involves forming a first spot at the weld seam between two aluminum alloy parts using a Gaussian laser, and a second spot at the weld seam using a flat-top laser. The first and second spots are moved along a first direction, and welding wire is provided to the weld seam at the second spot. This allows the substrate at the weld seam to be rapidly melted by the first spot of the Gaussian laser, while the welding wire is simultaneously melted by the second spot of the flat-top laser, filling the weld seam. Utilizing the uniform energy distribution of the second spot of the flat-top laser, the melting efficiency of the welding wire is improved, and the temperature gradient of the molten pool and the solidification cooling rate are reduced, thereby solving the problem of weld cracks between aluminum alloy parts.

[0044] Figure 1 A flowchart illustrating one embodiment of the laser welding method for suppressing weld cracks in aluminum alloys provided in this application. Figure 1 As shown, the laser welding method for suppressing weld cracks in aluminum alloys includes steps S110 to S140, which are described in detail below:

[0045] S110. Position the two aluminum alloy parts 400 so that a first direction is formed between the two aluminum alloy parts 400.

[0046] X-shaped extension of the seam to be welded.

[0047] like Figure 3 As shown, two aluminum alloy parts 400 can be supported and positioned by the positioning mechanism 310 of the laser welding device 200, thereby positioning the two aluminum alloy parts 400 and forming a weld seam extending along the first direction X between the two aluminum alloy parts 400.

[0048] The two aluminum alloy parts 400 can be stacked vertically or arranged side-by-side horizontally. The material of the aluminum alloy parts 400 includes at least one of 6xxx, 7xxx, and 2xxx aluminum alloys. The aluminum alloy parts 400 can be plate-shaped, block-shaped, column-shaped, etc., depending on their intended use. The two aluminum alloy parts 400 can have the same or different shapes; no limitation is imposed here.

[0049] S120. The seam to be welded is irradiated by a Gaussian laser 3211 to form a first spot at the seam to be welded, and the first spot is moved relative to the two aluminum alloy parts 400 along the first direction X.

[0050] By forming a first spot with the Gaussian laser 3211 at the weld seam, the substrate of the two aluminum alloy parts 400 at the weld seam can be rapidly melted through the first spot, resulting in a deeper weld depth. Specifically, the Gaussian laser 321 emitting the Gaussian laser 3211 can be moved along a first direction X, causing the first spot to move relative to the two aluminum alloy parts 400 along the first direction X; alternatively, the two aluminum alloy parts 400 can also be moved along the first direction X, causing the first spot to move relative to the two aluminum alloy parts 400 along the first direction X.

[0051] like Figure 3 As shown, the Gaussian laser 321 of the laser welding device 200 can be used to emit a Gaussian laser 3211 at the weld seam between two aluminum alloy parts 400 to form a first light spot at the weld seam. The Gaussian laser 321 can be moved relative to the two aluminum alloy parts 400 along the first direction X by a drive assembly or by manual drive, thereby moving the first light spot relative to the two aluminum alloy parts 400 along the first direction X.

[0052] In some embodiments, the moving speed of the first spot of the Gaussian laser 3211 along the first direction X is greater than or equal to 1 m / min, to avoid the first spot moving too slowly, which would result in too much substrate being melted at the weld seam between the two aluminum alloy parts 400. The moving speed of the first spot of the Gaussian laser 3211 can be 1.5 m / min, 2 m / min, 2.5 m / min, 3.5 m / min, etc., and can be determined based on factors such as the power of the Gaussian laser 3211 and the thickness of the aluminum alloy part 400.

[0053] Additionally, the moving speed of the first spot of the Gaussian laser 3211 along the first direction X can be less than or equal to 3 m / min to prevent the first spot of the Gaussian laser 3211 from failing to melt the substrate of the two aluminum alloy parts 400 at the weld joint in time. The moving speed of the first spot of the Gaussian laser 3211 can be 2.7 m / min, 2.3 m / min, 1.8 m / min, 1.2 m / min, etc., and can be determined according to factors such as the power of the Gaussian laser 3211 and the thickness of the aluminum alloy part 400.

[0054] Specifically, the first spot of the Gaussian laser 3211 can be moved at a speed greater than or equal to 1 m / min and less than or equal to 3 m / min along the first direction X, so that the amount of substrate melted by the first spot at the weld seam of the two aluminum alloy parts 400 is moderate, which is beneficial to improving the weld quality of the two aluminum alloy parts 400.

[0055] In some embodiments, the power of the Gaussian laser 3211 is greater than or equal to 1KW to avoid the first spot of the Gaussian laser 3211 failing to melt the substrate of the two aluminum alloy parts 400 at the weld seam in time due to insufficient power. The power of the Gaussian laser 3211 can be 1.5KW, 2KW, 2.5KW, 3.5KW, etc.

[0056] Additionally, the power of the Gaussian laser 3211 can be less than or equal to 3KW to avoid excessive power causing too much of the base material to be melted at the weld joint between the two aluminum alloy parts 400, thus affecting the weld quality. The power of the Gaussian laser 3211 can be 2.7KW, 2.3KW, 1.8KW, 1.2KW, etc.

[0057] The power of the Gaussian laser 3211 can be greater than or equal to 1KW and less than or equal to 3KW, so that the amount of substrate melted by the first spot at the weld seam of the two aluminum alloy parts 400 is moderate, thereby improving the weld quality of the two aluminum alloy parts 400.

[0058] In some preferred embodiments, the first spot of the Gaussian laser 3211 can move at a speed greater than or equal to 1 m / min and less than or equal to 3 m / min along the first direction X. At the same time, the power of the Gaussian laser 3211 is greater than or equal to 1 kW and less than or equal to 3 kW, so as to further improve the melting effect of the Gaussian laser 3211 on the substrate of the two aluminum alloy parts 400 at the weld seam.

[0059] S130. The weld seam to be welded is irradiated by a flat-top laser 3221 to form a second spot at the weld seam, and the second spot moves relative to the two aluminum alloy parts 400 along the first direction X. The second spot and the first spot are distributed sequentially along the first direction X.

[0060] After the first spot of the Gaussian laser 3211 melts the substrate at the weld joint, the flat-top laser 3221 forms a second spot on the side opposite to the first spot along the first direction X, and moves the second spot in the same direction as the first spot. This reduces the temperature gradient and solidification cooling rate of the molten pool at the weld joint on the side opposite to the first spot's movement direction, thereby solving the problem of cracks appearing in the weld joint between the two aluminum alloy parts 400.

[0061] like Figure 3 As shown, the flat-top laser 3221 of the laser welding device 200 can be emitted towards the weld seam of the two aluminum alloy parts 400 to form a second laser spot at the weld seam. The flat-top laser 322 can be moved relative to the two aluminum alloy parts 400 along the first direction X by a drive assembly or by manual drive, thereby moving the second laser spot relative to the two aluminum alloy parts 400 along the first direction X.

[0062] S140, Provide welding wire 331 to the seam to be welded at the second spot.

[0063] Therefore, the second spot of the flat-top laser 3221 can melt the welding wire 331 to fill the weld seam, thereby further improving the weld strength of the two aluminum alloy parts 400. Figure 3 As shown, welding wire 331 can be provided to the weld seam at the second spot through the wire feeding mechanism 330 of the laser welding device 200.

[0064] The laser welding method for suppressing weld cracks in aluminum alloys provided in this application involves forming a first spot at the weld seam between two aluminum alloy parts 400 using a Gaussian laser 3211, and a second spot at the weld seam using a flat-top laser 3221. The first and second spots are moved along a first direction X, and welding wire 331 is provided to the weld seam at the second spot. This allows the first spot of the Gaussian laser 3211 to rapidly melt the substrate at the weld seam, while simultaneously melting the welding wire 331 using the second spot of the flat-top laser 3221. The welding wire 331 fills the weld seam. Utilizing the uniform energy distribution of the second spot of the flat-top laser 3221, the melting efficiency of the welding wire 331 is improved, and the temperature gradient of the molten pool and the solidification cooling rate are reduced, thereby solving the problem of weld cracks between the aluminum alloy parts 400.

[0065] In some embodiments, the distance between the second spot of the flat-top laser 3221 and the first spot of the Gaussian laser 3211 in the first direction X is less than or equal to 3 mm. This enhances the interaction between the second spot of the flat-top laser 3221 and the first spot of the Gaussian laser 3211, resulting in a larger molten pool at the weld joint of the two aluminum alloy parts 400. Furthermore, the temperature gradient and solidification cooling rate of the molten pool are lower, reducing the likelihood of cracks appearing in the weld joint between the two aluminum alloy parts 400. The specific distance between the second spot of the flat-top laser 3221 and the first spot of the Gaussian laser 3211 can be 0 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, etc., depending on factors such as the power and moving speed of the flat-top laser 3221 and the Gaussian laser 3211, and the material of the aluminum alloy parts 400.

[0066] It should be noted that the distance between the second light spot and the first light spot in the first direction X refers to the minimum distance between the edges of the second light spot and the first light spot in the first direction X. When the first light spot and the second light spot move synchronously in the first direction X, the distance between the second light spot of the flat-top laser 3221 and the first light spot of the Gaussian laser 3211 in the first direction X remains unchanged. When the first light spot and the second light spot move asynchronously in the first direction X, the distance between the second light spot of the flat-top laser 3221 and the first light spot of the Gaussian laser 3211 in the first direction X will change as the first light spot and the second light spot move.

[0067] In some embodiments, the moving speed of the first spot of the Gaussian laser 3211 along the first direction X is the same as the moving speed of the second spot of the flat-top laser 3221 along the first direction X. This allows the size of the molten pool to remain stable, as well as the temperature gradient and solidification cooling rate of the molten pool, thereby further preventing cracks from appearing in the weld between the two aluminum alloy parts 400.

[0068] In some embodiments, the power of the flat-top laser 3221 is greater than or equal to 0.5 kW, so that the flat-top laser 3221 can melt the welding wire 331 more quickly. Furthermore, it can maintain a higher temperature in the molten pool near the second laser spot, thereby reducing the temperature gradient of the molten pool in the first direction X and lowering the solidification cooling rate of the molten pool. The power of the flat-top laser 3221 can be 0.7 kW, 1 kW, 1.5 kW, etc.

[0069] Additionally, the power of the flat-top laser 3221 can be less than or equal to 2KW to avoid excessively high temperatures in the molten pool near the second spot, which would result in a large temperature gradient in the molten pool near the second spot along the opposite side of the first direction X. The power of the flat-top laser 3221 can be 1.8KW, 1.3KW, 0.9KW, etc.

[0070] In some preferred embodiments, the power of the flat-top laser 3221 can be greater than or equal to 0.5KW and less than or equal to 2KW, so that the molten pool has a lower temperature gradient and a lower solidification cooling rate.

[0071] In some embodiments, the diameter of the welding wire 331 is greater than or equal to 1 mm and less than or equal to 1.6 mm, and the wire feed speed of the welding wire 331 is greater than or equal to 3 m / min and less than or equal to 6 m / min. This allows the welding wire 331 to be melted by the second spot of the flat-top laser 3221 and fill the weld seam more completely, reducing the likelihood of incomplete or excessive filling. The material of the welding wire 331 may include one or more of Al-Si5, Al-Mg5, and Al-Cu5 to further improve the welding effect on the two parts to be welded.

[0072] In some embodiments, a protective gas may be provided to the area where the first light spot is located, the area where the second light spot is located, and the area between the first light spot and the second light spot to protect the area where the first light spot is located, the area where the second light spot is located, and the area between the first light spot and the second light spot, thereby improving the quality of the weld between the two aluminum alloy parts 400.

[0073] The protective gas can be supplied through the air supply mechanism of the laser welding device 200. The protective gas can be argon or other inert gases. Furthermore, the flow rate of the protective gas can be greater than or equal to 10 L / min and less than or equal to 25 L / min.

[0074] It should be noted that the above steps S120 to S140 are not in any particular order. Steps S120 to S140 can be performed simultaneously or in a specific order, as long as the welding process of the two aluminum alloy parts 400 can be completed.

[0075] In some embodiments, the aluminum alloy part 400 is an aluminum alloy plate with a thickness greater than or equal to 1 mm and less than or equal to 3 mm, so as to improve the welding effect of the laser welding method for suppressing aluminum alloy welding cracks in this application on two aluminum alloy parts 400.

[0076] In some embodiments, the laser welding method for suppressing welding cracks in aluminum alloys further includes: oscillating a first light spot relative to two aluminum alloy plates in a second direction Y, wherein the second direction Y forms an angle with the first direction X; or oscillating the first light spot relative to two aluminum alloy plates in both the second direction Y and the first direction X, wherein the second direction Y forms an angle with the first direction X, and the oscillation trajectory of the first light spot is a ring or two rings connected sequentially in the first direction X.

[0077] Therefore, the area of ​​the two aluminum alloy parts 400 irradiated by the first spot can be wider in the second direction Y, thereby increasing the width of the molten pool in the second direction Y. In addition, by oscillating the first spot along the first direction X and / or the second direction Y, porosity in the molten pool can be removed to a certain extent, thereby further improving the weld strength of the two aluminum alloy parts 400.

[0078] The first spot of the Gaussian laser 3211 can be controlled to oscillate in the first direction X and / or the second direction Y by the first galvanometer assembly (not shown in the figure) of the laser welding device 300. The oscillation stroke of the first spot of the Gaussian laser 3211 in the first direction X and / or the second direction Y is greater than or equal to 0.5 mm to avoid the oscillation amplitude of the first spot of the Gaussian laser 3211 being too small, resulting in an excessively small width of the molten pool in the second direction Y. The oscillation stroke of the first spot of the Gaussian laser 3211 in the first direction X and / or the second direction Y can be 0.7 mm, 0.9 mm, 1.5 mm, 1.8 mm, etc., and can be determined according to parameters such as the size of the first spot, the power of the Gaussian laser 3211, and the width of the seam to be welded.

[0079] It should be noted that the swing stroke of the first spot of the Gaussian laser 3211 in the first direction X or the second direction Y can be greater than or equal to 0.5 mm, or the swing stroke of the first spot of the Gaussian laser 3211 in both the first direction X and the second direction Y can be greater than or equal to 0.5 mm.

[0080] Furthermore, the oscillation stroke of the first spot of the Gaussian laser 3211 in the first direction X and / or the second direction Y is less than or equal to 2 mm. This is to avoid excessive oscillation of the first spot's stroke, which would cause the heat from the first spot to be too dispersed, thus affecting the melting efficiency of the substrate on both sides of the weld seam. The oscillation stroke of the first spot of the Gaussian laser 3211 in the first direction X and / or the second direction Y can be 1.3 mm, 1 mm, 0.8 mm, 0.6 mm, etc., and can be determined based on parameters such as the size of the first spot, the power of the Gaussian laser 3211, and the width of the weld seam.

[0081] In some preferred embodiments, the first spot of the Gaussian laser 3211 can be made to swing a distance greater than or equal to 0.5 mm and less than or equal to 2 mm in the first direction X and / or the second direction Y, so that the first spot of the Gaussian laser 3211 can quickly melt the aluminum alloy part 400 to form a molten pool while the molten pool has a large width.

[0082] In some embodiments, the oscillation frequency of the first spot of the Gaussian laser 3211 is greater than or equal to 50 Hz and less than or equal to 200 Hz, so as to make the temperature distribution in the molten pool region corresponding to the first spot more uniform. The oscillation frequency of the first spot of the Gaussian laser 3211 can be 80 Hz, 100 Hz, 150 Hz, etc., and can be determined according to factors such as the oscillation trajectory of the Gaussian laser 3211 and the size of the first spot.

[0083] In some embodiments, the laser welding method for suppressing welding cracks in aluminum alloys further includes: oscillating the second spot relative to the two aluminum alloy plates in a second direction Y, wherein the second direction Y forms an angle with the first direction X; or oscillating the second spot relative to the two aluminum alloy plates in both the second direction Y and the first direction X, wherein the second direction Y forms an angle with the first direction X, and the oscillation trajectory of the second spot is a ring or two rings connected sequentially in the first direction X.

[0084] Therefore, the area of ​​the two aluminum alloy parts 400 irradiated by the second spot can be wider in the second direction Y, thereby increasing the temperature gradient and solidification cooling rate of the molten pool in the second direction Y. In addition, by oscillating the second spot along the first direction X and / or the second direction Y, porosity in the molten pool can be removed to a certain extent, thereby further improving the weld strength of the two aluminum alloy parts 400.

[0085] It should be noted that the oscillation trajectory of the second spot of the flat-top laser 3221 can be the same as or different from the oscillation trajectory of the first spot of the Gaussian laser 3211. Furthermore, it is possible to make only the second spot of the flat-top laser 3221 oscillate while the first spot of the Gaussian laser 3211 remains stationary, or to make the second spot of the flat-top laser 3221 oscillate while the first spot of the Gaussian laser 3211 remains stationary. Of course, it is also possible to make both the second spot of the flat-top laser 3221 and the first spot of the Gaussian laser 3211 oscillate.

[0086] The second spot of the flat-top laser 3221 can be controlled to oscillate in the first direction X and / or the second direction Y by the second galvanometer assembly (not shown in the figure) of the laser welding device 300. The oscillation stroke of the second spot of the flat-top laser 3221 in the first direction X and / or the second direction Y is greater than or equal to 0.5 mm and less than or equal to 2 mm. This is to avoid the oscillation amplitude of the second spot of the Gaussian laser 3221 being too small, resulting in an excessively small width of the molten pool in the second direction Y, and to avoid the stroke of the second spot of the Gaussian laser 3221 being too large, resulting in excessive heat dispersion of the second spot of the Gaussian laser 3211, thus causing an excessively large temperature gradient of the molten pool in the second direction Y. The oscillation stroke of the second spot of the flat-top laser 3221 in the first direction X and / or the second direction Y can be 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.3 mm, 1.5 mm, 1.8 mm, etc.

[0087] It should be noted that the swing stroke of the second spot of the flat-top laser 3221 in the first direction X or the second direction Y can be greater than or equal to 0.5 mm and less than or equal to 2 mm. Alternatively, the swing stroke of the second spot of the flat-top laser 3221 in both the first direction X and the second direction Y can be greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0088] In some embodiments, the oscillation frequency of the second spot of the flat-top laser 3221 can be greater than or equal to 50Hz and less than or equal to 200Hz to make the temperature distribution in the molten pool region corresponding to the second spot more uniform. The oscillation frequency of the second spot of the flat-top laser 3221 can be 80Hz, 100Hz, 150Hz, etc., and can be determined according to factors such as the oscillation trajectory of the flat-top laser 3221 and the size of the second spot.

[0089] In some embodiments, the laser welding method for suppressing welding cracks in aluminum alloys further includes: oscillating the second laser spot synchronously with the first laser spot. That is, the oscillation trajectories of the first laser spot of the Gaussian laser 3211 and the second laser spot of the flat-top laser 3221 are the same, and the oscillation speed and oscillation direction are the same.

[0090] In some embodiments, the laser welding method for suppressing welding cracks in aluminum alloys further includes: removing the oxide layer on the surface of the aluminum alloy part 400; and cleaning the surface of the aluminum alloy part 400.

[0091] The oxide layer on the surface of the aluminum alloy part 400 can be removed mechanically, or chemically or by other means. By removing the oxide layer and cleaning the surface of the aluminum alloy part 400, the oxide layer or impurities on the surface of the aluminum alloy part 400 can be prevented from affecting the welding effect of the two aluminum alloy parts 400.

[0092] In some embodiments, the surface of the aluminum alloy part 400 after the oxide layer has been removed can be cleaned with a cleaning agent containing acetone to further improve the cleaning effect on the aluminum alloy surface.

[0093] To achieve better welding results on two parts and more effectively suppress the formation of welding cracks in aluminum alloys, this application also provides a laser welding method for suppressing welding cracks in aluminum alloys, such as... Figure 2 As shown, the method includes steps S210 to S250, which are described in detail below:

[0094] S210. Position two aluminum alloy plates to form a weld seam extending along the first direction X between the two aluminum alloy plates. The material of the aluminum alloy plates includes at least one of 6xxx aluminum alloy, 7xxx aluminum alloy and 2xxx aluminum alloy. The thickness of the aluminum alloy plates is greater than or equal to 1 mm and less than or equal to 3 mm.

[0095] S220. The weld seam to be welded is irradiated by a Gaussian laser 3211 to form a first spot at the weld seam, and the first spot moves relative to the two aluminum alloy plates along the first direction X. The power of the Gaussian laser 3211 is greater than or equal to 1KW and less than or equal to 3KW, and the moving speed of the first spot along the first direction X is greater than or equal to 1m / min and less than or equal to 3m / min.

[0096] S230. The weld seam to be welded is irradiated by a flat-top laser 3221 to form a second spot at the weld seam, and the second spot moves synchronously with the first spot. The second spot and the first spot are distributed sequentially along the first direction X. The distance between the second spot and the first spot in the first direction X is less than or equal to 3mm. The power of the flat-top laser 3221 is greater than or equal to 0.5KW and less than or equal to 2KW.

[0097] S240. Provide welding wire 331 to the weld seam to be welded at the second spot. The diameter of welding wire 331 is greater than or equal to 1 mm and less than or equal to 1.6 mm. The wire feeding speed of welding wire 331 is greater than or equal to 3 m / min and less than or equal to 6 m / min.

[0098] S250, Provide protective gas to the area where the first light spot is located, the area where the second light spot is located, and the area between the first light spot and the second light spot, wherein the flow rate of the protective gas is greater than or equal to 10 L / min and less than or equal to 25 L / min.

[0099] The laser welding method for suppressing weld cracks in aluminum alloys provided in this application involves forming a first spot at the weld seam between two aluminum alloy parts 400 using a Gaussian laser 3211, and forming a second spot at the weld seam using a flat-top laser 3221. The second spot and the first spot are sequentially distributed along a first direction X and move synchronously along the same direction X, while a welding wire 331 is provided to the weld seam at the second spot. This allows the first spot of the Gaussian laser 3211 to melt the substrate at the weld seam, while simultaneously the second spot of the flat-top laser 3221 melts the welding wire 331, filling the weld seam. Utilizing the uniform energy distribution of the second spot of the flat-top laser 3221, the melting efficiency of the welding wire 331 is improved, and the temperature gradient of the molten pool and the solidification cooling rate are reduced, thereby solving the problem of weld cracks between the aluminum alloy parts 400.

[0100] Based on this, by providing protective gas to the area where the first spot is located, the area where the second spot is located, and the area between the first spot and the second spot, the quality of the weld of the two aluminum alloy parts 400 can be further improved, thereby increasing the weld strength.

[0101] This application also provides a laser welding device for suppressing welding cracks in aluminum alloys. This laser welding device is used to perform the laser welding method for suppressing welding cracks in aluminum alloys in any of the above embodiments. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0102] like Figure 3 As shown, the laser welding apparatus 300 for suppressing welding cracks in aluminum alloys includes a positioning mechanism 310, a welding mechanism 320, and a wire feeding mechanism 330. The positioning mechanism 310 supports and positions two aluminum alloy parts 400, forming a weld seam extending along a first direction X between the two aluminum alloy parts 400. The welding mechanism 320 performs fusion welding on the weld seam between the two aluminum alloy parts 400. The wire feeding mechanism 330 feeds welding wire 331 into the weld seam between the two aluminum alloy parts 400, so that the welding wire 331 is melted by the welding mechanism 320 and fills the weld seam between the two aluminum alloy parts 400.

[0103] The welding mechanism 320 includes a Gaussian laser 321, a flat-top laser 322, and a driving assembly (not shown in the figure). The Gaussian laser 321 emits a Gaussian laser 3211 towards the weld seam between the two aluminum alloy parts 400 to form a first laser spot at the weld seam. The flat-top laser 322 emits a flat-top laser 3221 towards the weld seam between the two aluminum alloy parts 400 to form a second laser spot at the weld seam. The second laser spot and the first laser spot are sequentially distributed along a first direction X. The driving assembly is connected to the Gaussian laser 321 and the flat-top laser 322 and drives the Gaussian laser 321 and the flat-top laser 322 to move relative to the two aluminum alloy parts 400 along the first direction X, thereby moving the first laser spot and the second laser spot along the first direction X. The wire feeding mechanism 330 provides welding wire 331 to the weld seam at the second laser spot.

[0104] The laser welding apparatus 300 for suppressing weld cracks in aluminum alloys provided in this application uses a Gaussian laser 3211 to form a first spot at the weld seam between two aluminum alloy parts 400, and a flat-top laser 3221 to form a second spot at the weld seam. The second spot and the first spot are sequentially distributed and moved along the first direction X, and welding wire 331 is provided to the weld seam at the second spot. Thus, the first spot of the Gaussian laser 3211 melts the substrate at the weld seam, and simultaneously the second spot of the flat-top laser 3221 melts the welding wire 331, allowing the welding wire 331 to fill the weld seam. Utilizing the uniform energy distribution of the second spot of the flat-top laser 3221, the melting efficiency of the welding wire 331 is improved, and the temperature gradient of the molten pool and the solidification cooling rate are reduced, thereby solving the problem of weld cracks between the aluminum alloy parts 400.

[0105] The distance between the first spot of the Gaussian laser 3211 and the second spot of the flat-top laser 3221 is less than or equal to 3 mm. Additionally, the driving assembly is used to drive the Gaussian laser 321 and the flat-top laser 322 to move synchronously relative to the two aluminum alloy parts 400 along the first direction X.

[0106] In addition, the laser welding apparatus 300 for suppressing welding cracks in aluminum alloys also includes a gas supply mechanism (not shown in the figure) for providing protective gas to the area where the first spot is located, the area where the second spot is located, and the area between the first spot and the second spot.

[0107] The parameters related to the first spot of the Gaussian laser 3211 and the second spot of the flat-top laser 3221 can be referred to in the above embodiments, and will not be repeated here. Additionally, the parameters related to the wire feeding mechanism 330 providing the welding wire 331, and the parameters related to the shielding gas provided by the feeding mechanism, can be referred to in the above embodiments, and will not be repeated here.

[0108] In some embodiments, the laser welding apparatus 300 for suppressing welding cracks in aluminum alloys further includes a first galvanometer scanning assembly (not shown in the figure), which includes a first galvanometer disposed in the optical path of the Gaussian laser 3211, and a first driving mechanism connected to the first galvanometer. The first driving mechanism drives the galvanometer to swing, thereby causing the first spot of the Gaussian laser 3211 to swing relative to the two aluminum alloy plates in a second direction Y, the second direction Y forming an angle with the first direction X; or, causing the first spot to swing relative to the two aluminum alloy plates in both the second direction Y and the first direction X, the second direction Y forming an angle with the first direction X, and the swing trajectory of the first spot being a ring or two rings connected sequentially in the first direction X.

[0109] Specifically, the oscillation stroke of the first spot of the Gaussian laser 3211 in the first direction X and / or the second direction Y can be greater than or equal to 0.5 mm and less than or equal to 2 mm. Additionally, the oscillation frequency of the first spot of the Gaussian laser 3211 can be greater than or equal to 50 Hz and less than or equal to 200 Hz.

[0110] In some embodiments, the laser welding apparatus 300 for suppressing welding cracks in aluminum alloys further includes a second galvanometer scanning assembly (not shown in the figure), which includes a second galvanometer disposed on the optical path of the flat-top laser 3221, and a second driving mechanism connected to the second galvanometer. The second driving mechanism drives the galvanometer to swing, thereby causing the second spot of the flat-top laser 3221 to swing relative to the two aluminum alloy plates in a second direction Y, the second direction Y forming an angle with the first direction X; or, causing the second spot to swing relative to the two aluminum alloy plates in both the second direction Y and the first direction X, the second direction Y forming an angle with the first direction X, and the swing trajectory of the second spot being a ring or two rings connected sequentially in the first direction X.

[0111] Specifically, the second spot of the flat-top laser 3221 has a swing stroke in the first direction X and / or the second direction Y that is greater than or equal to 0.5 mm and less than or equal to 2 mm. Furthermore, the swing frequency of the second spot of the flat-top laser 3221 is greater than or equal to 50 Hz and less than or equal to 200 Hz.

[0112] The effects of the laser welding method and apparatus for suppressing welding cracks in aluminum alloys provided in the embodiments of this application will be described below through different laser welding methods.

[0113] In the first laser welding method, two 2.0mm thick 6061 aluminum alloy plates were selected. The surface oxide scale was removed mechanically, and surface oil was removed with acetone and the plates were dried. The cleaned aluminum alloy plates were then placed overlapping on the worktable and fixed by the positioning mechanism 310. Next, commercially available Al-Mg5 welding wire 331 with a diameter of 1.2mm was used as filler wire 331, and welding was performed using a CWX-3000 (Gauss laser 321) fiber laser test board. The laser power was 1.4kW, the welding speed was 1.4m / min, and the wire feed speed was 3.0m / min. Figure 4 As shown, the weld surface is uneven and there are obvious cracks on the weld surface.

[0114] In the second laser welding method, two 2mm thick 6061 aluminum alloy plates are selected. The surface oxide scale is removed mechanically, and surface oil is removed with acetone and the plates are dried. Afterward, the cleaned aluminum alloy plates are placed overlapping on the worktable and fixed by the positioning mechanism 310. Then, commercially available Al-Mg5 welding wire 331 with a diameter of 1.2mm is used as filler wire 331. The aluminum alloy plates are welded using a laser welding device 300 consisting of a CWX-3000 fiber laser (Gaussian laser 321) and a CMT 500i (flat-top laser 322). The Gaussian beam is in front with a power of 1.4kW, and the flat-top beam is behind with a power of 1.1kW. The first spot of the Gaussian laser 3211 and the second spot of the flat-top laser 3221 oscillate in an "O" shape (ring), with an oscillation stroke of 1.0mm and an oscillation frequency of 100Hz. The welding speed is 1.4m / min, and the wire feed speed is 3.0m / min. Figure 5 As shown, the weld has a good macroscopic morphology after welding, with no obvious spatter, and no obvious cracks in the weld cross-section. Moreover, the tensile strength of the welded joint is 15% higher than that of the first laser welding method.

[0115] In the third laser welding method, two 2mm thick 2219 aluminum alloy plates are selected. The surface oxide scale is removed mechanically, and surface oil is removed with acetone and the plates are dried. After cleaning, the aluminum alloy plates are placed overlapping on the worktable and fixed by the positioning mechanism 310. Then, commercially available Al-Cu5 welding wire 331 with a diameter of 1.2mm is used as filler wire 331. A laser welding device 300 consisting of a CWX-3000 fiber laser (Gaussian laser 321) and a CMT 500i (flat-top laser 322) is used to weld the aluminum alloy plates. The Gaussian beam is in front with a power of 1.6kW, and the flat-top beam is behind with a power of 0.6kW. The first spot of the Gaussian laser 3211 and the second spot of the flat-top laser 3221 oscillate in an "O" shape (ring), with an oscillation stroke of 1.2mm and an oscillation frequency of 150Hz. The welding speed is 1.2m / min, and the wire feed speed is 3.6m / min. Figure 6 As shown, the weld has a good macroscopic morphology, no obvious spatter, and no obvious cracks in the weld cross-section. Moreover, the tensile strength of the welded joint is 15% higher than that of the first laser welding method.

[0116] In the fourth laser welding method, two 2mm thick 7075 aluminum alloy plates are selected. The surface oxide scale is removed mechanically, and the surface oil is removed with acetone and dried. After cleaning, the aluminum alloy plates are placed on the worktable in an overlapping manner and fixed by the positioning mechanism 310. Then, a commercial Al-Si5 welding wire 331 with a diameter of 1.2mm is used as the filler wire 331. The aluminum alloy plates are welded using a laser welding device 300 consisting of a CWX-3000 fiber laser (Gaussian laser 321) and a CMT 500i (flat-top laser 322). The Gaussian beam is in front with a power of 1.5kW, and the flat-top beam is behind with a power of 0.7kW. The first spot of the Gaussian laser 3211 and the second spot of the flat-top laser 3221 swing trajectory is "∞" shaped (two rings). The swing stroke in the second direction Y is 0.5mm, and the swing frequency is 150Hz. The welding speed is 1.2m / min, and the wire feed speed is 3.0m / min. like Figure 7 As shown, the weld has a good macroscopic morphology, no obvious spatter, and no obvious cracks in the weld cross-section. Moreover, the tensile strength of the welded joint is 12% higher than that of the first laser welding method.

[0117] As can be seen from different laser welding methods, the laser welding method and apparatus for suppressing weld cracks in aluminum alloys provided in this application can effectively solve the problem of cracks in the weld between aluminum alloy parts and improve the strength of the weld.

[0118] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0119] The above provides a detailed description of a laser welding method and apparatus for suppressing welding cracks in aluminum alloys, as provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. 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. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A laser welding method for suppressing welding cracks in aluminum alloys, characterized in that, The method includes: Two aluminum alloy plates are positioned such that a weld seam extending in a first direction is formed between the two aluminum alloy plates. The material of the aluminum alloy plates includes at least one of 6xxx aluminum alloy, 7xxx aluminum alloy and 2xxx aluminum alloy. The thickness of the aluminum alloy plates is greater than or equal to 1 mm and less than or equal to 3 mm. The weld seam is irradiated with a Gaussian laser to form a first spot at the weld seam. The first spot moves relative to the two aluminum alloy plates in a first direction and oscillates in a second direction, with the second direction forming an angle with the first direction. The power of the Gaussian laser is greater than or equal to 1 kW and less than or equal to 3 kW. The moving speed of the first spot in the first direction is greater than or equal to 1 m / min and less than or equal to 3 m / min. The oscillation stroke of the first spot in the second direction is greater than or equal to 0.5 mm and less than or equal to 2 mm. The oscillation frequency of the first spot in the second direction is greater than or equal to 50 Hz and less than or equal to 200 Hz. The weld seam is irradiated by a flat-top laser to form a second spot at the weld seam, and the second spot is moved relative to the two aluminum alloy plates along the first direction. The second spot and the first spot are distributed sequentially along the first direction. The distance between the second spot and the first spot in the first direction is less than or equal to 3 mm. The power of the flat-top laser is greater than or equal to 0.5 KW and less than or equal to 2 KW. Welding wire is provided to the seam to be welded at the second light spot.

2. The laser welding method for suppressing welding cracks in aluminum alloys as described in claim 1, characterized in that, The first light spot moves at the same speed as the second light spot along the first direction.

3. The laser welding method for suppressing welding cracks in aluminum alloys as described in claim 1 or 2, characterized in that, The diameter of the welding wire is greater than or equal to 1 mm and less than or equal to 1.6 mm; the wire feeding speed of the welding wire is greater than or equal to 3 m / min and less than or equal to 6 m / min.

4. A laser welding device for suppressing welding cracks in aluminum alloys, characterized in that, include: A positioning mechanism is used to support and position two aluminum alloy plates, forming a weld seam extending in a first direction between the two aluminum alloy plates. The material of the aluminum alloy plates includes at least one of 6xxx aluminum alloy, 7xxx aluminum alloy and 2xxx aluminum alloy, and the thickness of the aluminum alloy plates is greater than or equal to 1 mm and less than or equal to 3 mm. A welding mechanism includes a Gaussian laser, a flat-top laser, and a driving assembly. The Gaussian laser emits a Gaussian laser beam towards the weld seam between two aluminum alloy plates to form a first laser spot at the weld seam. The flat-top laser emits a flat-top laser beam towards the weld seam between the two aluminum alloy plates to form a second laser spot at the weld seam. The second laser spot and the first laser spot are sequentially distributed along a first direction. The driving assembly is connected to the Gaussian laser and the flat-top laser and drives the Gaussian laser and the flat-top laser to move relative to the two aluminum alloy plates along the first direction, causing the first laser spot and the second laser spot to move relative to the two aluminum alloy plates along the first direction, and... The first light spot oscillates along a second direction, which forms an angle with the first direction; the power of the Gaussian laser is greater than or equal to 1KW and less than or equal to 3KW; the moving speed of the first light spot along the first direction is greater than or equal to 1m / min and less than or equal to 3m / min; the oscillation stroke of the first light spot in the second direction is greater than or equal to 0.5mm and less than or equal to 2mm; the oscillation frequency of the first light spot in the second direction is greater than or equal to 50Hz and less than or equal to 200Hz; the distance between the second light spot and the first light spot in the first direction is less than or equal to 3mm; and the power of the flat-top laser is greater than or equal to 0.5KW and less than or equal to 2KW. A wire feeding mechanism is used to provide welding wire to the weld seam at the second spot.

5. The laser welding apparatus for suppressing welding cracks in aluminum alloys as described in claim 4, characterized in that, The driving component is used to drive the Gaussian laser and the flat-top laser to move synchronously relative to the two aluminum alloy plates along the first direction.

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