Aluminum alloy laser welding method

Abstract

The aluminum alloy laser welding method comprises the following steps that a first part is provided, the first part is provided with a wall part, a second part is provided, the second part is provided with a first welding wall, the wall part and / or the first welding wall comprise / comprises a multi-silicon material, and the multi-silicon material comprises, by mass, 85%-95% of Al and 5%-15% of Si; one of the first part and the second part comprises a first base material, the other one of the first part and the second part comprises the first base material or a second base material, the first base material and the second base material are aluminum alloy, and the first base material comprises, by mass, 0.2%-1.8% of Si, 0.2%-3% of Mg and 95.2%-99.6% of Al; the second base material comprises the following components in percentage by mass: 0.05%-1.8% of Mn and 98.2%-99.95% of Al; the first welding wall is in butt joint with the wall part, and the first part and the second part are subjected to laser welding; and the anti-cracking sensitivity of weld joints is reduced, and the aluminum alloy welding quality is improved.

Description

Technical Field

[0001] This invention relates to a laser welding method, and more particularly to a laser welding method for aluminum alloys. Background Technology

[0002] Aluminum alloys can be joined by welding, including brazing, friction stir welding, and laser welding. Compared with brazing and friction stir welding, laser welding has advantages such as lower cost, simpler process, and environmental friendliness, and can be applied to aluminum alloy welding processes.

[0003] Laser welding involves irradiating the area to be welded with a laser. The laser energy melts the components, and after cooling, the welding is completed, thus fixing the components together. However, when laser welding 6-series aluminum alloys with 3-series aluminum alloys or 6-series aluminum alloys with 6-series aluminum alloys, weld cracking often occurs, reducing the quality of the aluminum alloy weld. Summary of the Invention

[0004] This application provides a laser welding method for aluminum alloys, which solves the problem of weld cracking at the weld joint of aluminum alloys and improves the welding quality.

[0005] This application provides a method for laser welding aluminum alloys, including the following steps:

[0006] Provide a first part, the first part having a wall portion,

[0007] A second part is provided, the second part having a first weld wall, the wall portion and / or the first weld wall comprising a polysilicon material, the polysilicon material comprising 85%-95% by mass Al and 5%-15% by mass Si; one of the first part and the second part comprising a first base material and the other part comprising a first base material or a second base material, the first base material and the second base material being aluminum alloys, the first base material comprising 0.2%-1.8% by mass Si, 0.2%-3% by mass Mg, and 95.2%-99.6% by mass Al, the second base material comprising 0.05%-1.8% by mass Mn and 98.2%-99.95% by mass Al;

[0008] The first weld wall is joined to the wall portion, and the first part and the second part are laser welded together.

[0009] Laser welding features rapid heating, cooling, and solidification, leading to rapid crystallization of the alloy material in the molten pool. During this rapid heating-crystallization process, low-melting-point eutectics precipitate first and form a liquid film at the grain boundaries in the weld. This liquid film is highly susceptible to cracking under stress. In the aforementioned technical solution, one of the first and second parts includes a first base material, and the other part includes either a first base material or a second base material. Both the first and second base materials are aluminum alloys. The first base material mainly comprises 0.2%-1.8% by mass Si and 0.2%-3% by mass Mg, while the second base material mainly comprises 0.05%-1.8% by mass Mn. The wall portion and / or the first weld wall includes a 5%-15% by mass Si multi-silicon material, whose main components are Al and Si. This material is used to adjust the alloy composition at the weld and improve and optimize the welding crystallization process of the molten pool. During laser welding, the increase in silicon in the molten pool can increase the precipitation of eutectic phase, increase the fluidity of the liquid alloy in the molten pool, reduce the probability of hot cracking, and thus improve the welding quality of aluminum alloys. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the mating of the first part and the second part in one embodiment;

[0011] Figure 2 This is a schematic diagram of the fit between the flow channel plate substrate and the cover plate in another embodiment;

[0012] Figure 3 This is a schematic diagram of the first tube and the first substrate in another embodiment;

[0013] Figure 4 A schematic diagram of the laser welding molten pool between the flow channel plate substrate and the cover plate;

[0014] Figure 5 Metallographic image of weld seam of welded component 1 in Example 1;

[0015] Figure 6 Metallographic image of the weld seam of welded component 2 in Example 2;

[0016] Figure 7 Metallographic image of weld seam of welded component 3 in Example 3;

[0017] Figure 8 Metallographic image of weld seam of welded component 4 in Example 4;

[0018] Figure 9 Metallographic image of weld seam 5 in the comparative example;

[0019] Figure label:

[0020] 1-First part, 11-Wall part, 2-Second part, 21-First welding wall, 3-Dating area, 110-Cover plate, 111-Aluminum alloy base material layer, 112-Addition layer, 113-Side wall part, 120-Flow channel plate substrate, 121-Groove, 122-Second welding wall, 123-Connecting platform, 130-Welcoming area, 300-First substrate, 301-Recessed part, 302-First platform, 303-Third welding wall, 33-Dating part, 400-First tube, 401-Ring part, 402-Ring wall. Detailed Implementation

[0021] The specific embodiments of the present invention are described below with reference to the accompanying drawings.

[0022] This application provides a laser welding method for aluminum alloys, applicable to laser welding between aluminum alloy workpieces with certain specific compositions. This includes laser welding between components made of 6-series aluminum alloy base material and 3-series or 6-series aluminum alloy base material. It can be applied to laser welding of aluminum alloy forgings and stampings, with applications including laser welding of flow channel plates / base plates and cover plates, pipes, and other aluminum alloy workpieces. The 6-series aluminum alloy base material grades can be: 6061, 6056, 6082, 6069, 6092, etc., and the 3-series aluminum alloy base material grades can be: 3003, 3203, 3004, 3104, 3007, 3005, 3011, 3130, etc.

[0023] In one embodiment, this application provides a laser welding method for aluminum alloys, comprising the following steps:

[0024] like Figure 1 As shown, a first part 1 is provided, having a wall portion 11, and a second part 2 is provided, having a first welded wall 21. The wall portion 11 and / or the first welded wall 21 are provided with a multi-silicon material containing 5% to 15% by mass of Si. The main components of the multi-silicon material include 85% to 95% by mass of Al and 5% to 15% by mass of Si. One of the first part 1 and the second part 2 includes a first base material, and the other part includes either a first base material or a second base material. The first base material and the second base material are aluminum alloys. The main components of the first base material include 0.2% to 1.8% by mass of Si, 0.2% to 3% by mass of Mg, and 95.2% to 99.6% by mass of Al. The main components of the second base material include 0.05% to 1.8% by mass of Mn and 98.2% to 99.95% by mass of Al. The first welding wall 21 is joined to the wall portion 11, with a gap n between the first welding wall 21 and the wall portion 11. The portion of the wall portion 11 that joins the first welding wall 21 in the height direction has a height s. The gap n is controlled to be ≤0.1s. The first part 1 and the second part 2 are laser welded.

[0025] like Figure 1 The H direction shown is the height direction. This application defines this direction as the height direction of each part, component, and structure, and it is only for illustrating the content of this application and does not limit the scope of protection claimed by this application. In some embodiments, when the positions of each part, component, and structure change, the height direction H is the relative direction of each position in each part, component, and structure.

[0026] In laser welding, increasing the mass percentage of silicon at the weld joint initially increases the grain size of the weld alloy. However, after reaching a certain point, the grain size gradually refines, but the degree of refinement significantly impacts weld cracking. Simultaneously, increasing silicon content initially increases the cooling rate of the weld region, then decreases; a rapid cooling rate is detrimental to the formation of fine grains. Therefore, it is necessary to adjust the effects of silicon on grain refinement and crystallization rate. By comprehensively adjusting the silicon mass percentage, the crystallization process during molten pool cooling can be altered, allowing low-melting-point silicon to precipitate preferentially, forming finer grains at grain boundaries, reducing the formation of eutectic films, thereby improving the bonding strength between grain boundaries and reducing crack initiation.

[0027] In some embodiments, the second part 2 is selected from a first aluminum alloy plate having an additive layer 112 and an aluminum alloy base material layer 111. If the second part 2 includes a first base material, the first base material includes the aluminum alloy base material layer 111; if the second part 2 includes a second base material, the second base material includes the aluminum alloy base material layer 111. The multi-silicon material includes the additive layer 112, the main components of which include Al and Si, wherein the mass percentage of Si is 5% to 7%. The additive layer 112 and the aluminum alloy base material layer 111 are stacked along the height direction of the first aluminum alloy plate, and the additive layer 112 and the aluminum alloy base material layer 111 are connected along the sidewalls of the first aluminum alloy plate to form a first weld wall 21; n ≤ 0.5 mm. The addition layer 112 in the second part 2 improves the process cycle time and increases the efficiency of the laser welding process during welding.

[0028] In some embodiments, the first aluminum alloy plate has a first aluminum alloy base layer and a second aluminum alloy base layer. An additive layer 112 is disposed between the first aluminum alloy base layer and the second aluminum alloy base layer. The first aluminum alloy base layer, the second aluminum alloy base layer, and the additive layer 112 are connected at least a portion of the sidewalls in the height direction of the first aluminum alloy plate to form a first welded wall 21. By designing the additive layer 112 between the two aluminum alloy base layers, a dense oxide film is formed on the outer surfaces of the first and second aluminum alloy base layers, effectively improving the corrosion resistance of the first aluminum alloy plate and reducing the probability of corrosion of the additive layer 112.

[0029] In some embodiments, a multi-silicon material is applied to the mating area 3 between the wall portion 11 and the first weld wall 21; the main component of the multi-silicon material is Al-xSi, where x is the mass percentage of Si element, and x ranges from 5% to 10%. Applying multi-silicon material to the weld joint can improve the flexibility of process design, and the multi-silicon material can be applied to walls and first weld walls of various shapes and structures, thus improving process flexibility.

[0030] In some embodiments, the main component of the multi-silicon material further includes 5% to 7% by mass of Mg. The addition of magnesium can improve the fluidity of the weld metal and control the fluidity of the weld metal within a certain range, so as to further repair weld defects and further reduce weld crack sensitivity.

[0031] In some embodiments, a single-spot laser beam is used to irradiate the area 3 above the mating region 3 between the wall portion 11 and the first welding wall 21. The diameter of the single-spot laser beam is controlled between 2 and 4 mm, the power range is controlled between 900 and 2000 W, and the laser welding speed is controlled between 10 and 40 mm / s. Using the aforementioned laser parameters, the width and depth of the molten pool between the wall portion and the first welding wall can be effectively controlled, which is beneficial for achieving a better weld structure.

[0032] In some embodiments, an annular laser beam is used to irradiate the area 3 above the mating region 3 between the wall 11 and the first welding wall 21. The inner ring power range of the annular laser beam is controlled between 400 and 600 W, the inner ring power range of the annular laser beam is controlled between 1000 and 1500 W, the laser welding speed is controlled between 20 and 30 mm / s, and the swing amplitude is controlled between 0.5 and 1 mm.

[0033] Laser beam power affects weld size and molten pool depth, while the size of the weld area and the depth of the molten pool affect the mass percentage of each element in the new alloy at the weld and the welding performance. With the addition of 5% to 15% silicon mass percentage in the multi-silicon material, controlling the power within the aforementioned range can control the silicon content at the weld within a certain range, further reducing the crack sensitivity of the weld and thus achieving better welding performance.

[0034] With other parameters remaining constant, laser welding speed significantly impacts the crystallization process of the liquid-phase alloy in the weld pool. Higher welding speeds result in faster cooling and crystallization of the liquid-phase alloy, while lower welding speeds lead to slower cooling and crystallization. Further control of the laser welding speed helps regulate the crystallization process of the liquid-phase alloy in the weld pool, controlling grain refinement and thus forming a crack-insensitive microstructure. Simultaneously, welding speed also significantly affects the weld width. Slower welding speeds result in a wider weld zone, while higher speeds result in a narrower weld zone. Adjusting the weld zone width allows for the regulation of alloy element proportions within the weld zone, ensuring that the percentage of silicon mass in the weld zone falls within the crack-insensitive area. Furthermore, adjusting the weld zone width allows for the regulation of the effective weld area, which influences overall welding performance, such as weld strength and sealing. Controlling the effective weld area within a specific range further optimizes welding performance.

[0035] Simultaneously, it is necessary to coordinate and adjust the inner ring power, outer ring power, welding speed, and swing amplitude of the annular laser beam to control the width and depth of the welding area within a certain range. At the same time, the proportion of the main alloy components in the welding area, especially the proportion of Si, should be controlled to keep the alloy composition of the welding area outside the crack-sensitive zone. The above parameter design can coordinate the effects of each parameter to reduce the probability of weld cracking and improve welding quality.

[0036] In some embodiments, the height of the first weld wall 21 is 'a', and the total height of the polysilicon material is 'b', where 'b' ranges from 10% to 30% of 'a'. Increasing the height of the polysilicon material allows for better control of the composition of the new alloy at the weld joint, but excessive increases in its height can reduce the corrosion resistance and strength of the aluminum alloy parts. Controlling the height of the polysilicon material within a certain range can reduce the impact of adding polysilicon material on the corrosion resistance and strength of the second part 2, and ensure that the silicon content of the new alloy in the weld after welding is within the non-crack-sensitive zone.

[0037] In some embodiments, the value of b ranges from 2 to 4 mm, and the value of a ranges from 0.2 to 1.2 mm. The addition of multi-silicon material within this range does not significantly negatively impact the strength of the aluminum alloy part, meeting the strength requirements of the aluminum alloy. Furthermore, it allows for the adjustment of the main components within the new alloy after welding, reducing susceptibility to weld cracking. Increasing the total height b of the multi-silicon material can reduce the impact of hot cracking to some extent. Simultaneously, the introduction of multi-silicon material affects the corrosion resistance and mechanical strength of the second part 2. Thus, while achieving the required crack resistance by adjusting the mass percentage of silicon in the welded section, it also possesses superior corrosion resistance and mechanical strength.

[0038] In some embodiments, a laser beam irradiates the area 3 above the mating region of the first part 1 and the second part 2, controlling the width of the molten pool to be 2–5 mm and the depth of the molten pool to be 2–4 mm. Controlling the depth and width of the molten pool adjusts the mass percentage of each element in the liquid alloy phase within the molten pool to maintain it within the crack-insensitive zone, while simultaneously achieving superior welding performance.

[0039] In some embodiments, the laser welding amplitude is controlled within 0.5–1 mm. Controlling the amplitude adjusts the weld width, thereby enabling control of the elemental mass percentages in the weld metal and precise control of the welding area.

[0040] In another embodiment, such as Figure 2 As shown, the first part 1 is a flow channel plate substrate 120, which has a groove 121, a second welding wall 122, and a connecting platform 123. The wall portion 11 is located on the second welding wall 122, and the connecting platform 123 is connected to the second welding wall 122 and the wall of the groove 121. The second part 2 is a cover plate 110, with the first welding wall 21 located on the side wall portion 113 of the cover plate 110. In the step of "connecting the first welding wall 21 with the wall portion 11", the second welding wall 122 is connected to the side wall portion 113 by laser welding. The flow channel plate welded by the aluminum alloy laser welding method of this application has significantly improved sealing performance and significantly reduced weld cracking.

[0041] In yet another embodiment, such as Figure 3 As shown, the first component 1 is a first substrate 300, which has a recess 301, a first platform 302, and a third welding wall 303. The wall portion 11 is located on the third welding wall 303, and the third welding wall 303 is connected to the first platform 302. The wall of the recess 301 is connected to the first platform 302. The second component 2 is a first tube 400, which has an annular portion 401. The first welding wall 21 is located on the annular wall 402 on the outer periphery of the first tube 400, and the annular portion 401 is connected to the annular wall 402. In the step of "connecting the first welding wall 21 with the wall portion 11", the annular wall 402 is connected to the third welding wall 303 by laser welding. Specifically, the laser beam irradiates above the docking portion 33 at the docking point of the annular wall 402 and the third welding wall 303. In some embodiments, the end face of the annular portion 401 is circular. In other embodiments, the end face of the annular portion 401 can also be various shapes, such as an elliptical ring, a trapezoidal ring, a triangular ring, a polygonal ring, etc. In other embodiments, the end face of the ring portion 401 may also be a solid circle, triangle, polygon, ellipse, etc.

[0042] In some embodiments, the total thickness of the polysilicon material along the direction perpendicular to its height is x, and the total thickness of the ring portion 401 along the direction perpendicular to its height is y, wherein x ranges from 10% to 30% of y. The polysilicon material can be integrally formed or pre-coated inside the ring wall 402, or it can be added by adding polysilicon material placement nodes in a laser welding method.

[0043] Specifically, based on the inventive concept of this application, four specific sets of process parameters are listed for the implementation of laser welding of flow channel plates, namely Example 1, Example 2, Example 3, and Example 4, for comparison of different process parameters. In addition, using the same process parameters as in Example 3, three flow channel plate samples without added silicon material were laser welded to illustrate the improvement effect of adding silicon material on cracks.

[0044] The table below shows the process parameters for each embodiment and comparative example; see the description of each embodiment for details.

[0045] Table 1. Main process parameters used in the examples and comparative examples.

[0046]

[0047] Example 1

[0048] This embodiment uses the aluminum alloy laser welding method provided above to weld the flow channel plate, such as... Figure 2 As shown, the flow channel plate substrate 120 has a groove 121 and a second welding wall 122. The flow channel plate substrate 120 is made of 6-series aluminum alloy, and its main components include 0.7%-1.3% by mass Si and 0.6%-1.2% by mass Mg. The cover plate 110 has an additive layer 112 and an aluminum alloy base material layer 111. The additive layer 112 is located between the two aluminum alloy base material layers 111, and the cover plate 110 is similar to a sandwich structure. The aluminum alloy base material layer 111 is a 6-series aluminum alloy, and its main components include 0.4-0.8% by mass Si and 0.8-1.2% by mass Mg. The main components of the additive layer 112 include Al and Si, wherein the mass percentage of Si is 5% to 15%. The height of the cover plate 110 in the H direction is the same as the depth d of the second welded wall 122. The height can be designed to be 2-4mm. In this application, for the convenience of comparison and explanation, d is designed to be 3mm.

[0049] The cover plate 110 is riveted onto the flow channel plate substrate 120, so that Figure 2 The side end face of the cover plate 110 shown on the right is riveted to the second welding wall 122 of the flow channel plate substrate 120, clamped using a tooling fixture, and laser welded. In the mating state of the cover plate 110 and the flow channel plate substrate 120, the cover plate 110 is as follows... Figure 2The gap between the right end face and the second welding wall 122 shown is controlled to be less than 0.3mm to achieve high laser utilization. In this embodiment, the laser welding speed is 10mm / s, a ring laser beam is used, the inner ring power is 600W, the outer ring power is 1000W, and the swing amplitude is 0.5mm. During laser welding, the laser beam irradiates the area to be welded 130 formed by the butt joint of the cover plate 110 and the second welding wall 122 of the flow channel plate substrate 120. As the laser irradiates, the cover plate 110 and the second welding wall 122 gradually melt to form a molten pool, such as... Figure 4 As shown, a new liquid phase alloy forms in the molten pool, cools, and solidifies. Due to the addition of the additive layer 112, the liquid phase alloy in the molten pool is no longer a recombination of the alloy composition in the 6-series aluminum alloy base layer 111 and the flow channel plate substrate 120. The introduction of the additive layer 112 adjusts the composition of the liquid phase alloy in the molten pool, increasing the silicon content. The mass percentage of each component in the additive layer 112 and the process parameters can be adjusted to regulate the alloy composition in the molten pool, so that the mass percentage of silicon is between 1.2% and 12%. Due to the increased mass percentage of silicon in the molten pool, the crystallization process of the liquid phase alloy in the molten pool changes. Low-melting-point silicon precipitates first, forming crystal nuclei. The formation of a large number of crystal nuclei refines the weld alloy grains formed by the solidification of the liquid phase alloy, improving the weld strength.

[0050] One weldment was welded using the process described in this embodiment, and it is marked as 1.

[0051] Example 2

[0052] This embodiment continues to use... Figure 2 The implementation of the laser welding method for flow channel plates is illustrated as a schematic diagram. In this embodiment, the flow channel plate substrate 120 has a groove 121 and a second welding wall 122. The second welding wall 122 is configured to match the end face of the cover plate 110, and the cover plate 110 is placed on the flow channel plate substrate 120. The fluid passage 121 communicating with other parts of the flow channel plate other than the flow channel plate or other embodiments is not shown in the figure, but the fluid passage can be set according to conventional methods in the art. The cover plate 110 includes a second base material, which is a 3-series aluminum alloy, and the main components of the second base material include 0.05-1.8% by mass Mn. The flow channel plate substrate 120 includes a first base material, which is a 6-series aluminum alloy, and the main components of the first base material include 0.2-1.8% by mass Si and 0.2-3% by mass Mg. The main components of the additive layer 112 include Al, 5%-10% by mass Si, and 5%-7% by mass Mg. Laser welding is performed by irradiating the area above the mating zone between the second welding wall 122 and the cover plate 110 using a ring laser beam. The laser welding speed is 20 mm / s, the inner ring power of the laser beam is 600 W, the outer ring power of the laser beam is 1000 W, and the swing amplitude is 0.6 mm.

[0053] Before welding, the cover plate 110 is riveted onto the flow channel plate substrate 120, so that... Figure 2 The right cover plate 110 side wall 113 shown is mated with the second welded wall 122. The laser beam originates from... Figure 2 The area to be welded, 130, is irradiated from above by the laser beam. Under the heat of the laser beam, the area to be welded, 130, melts to form a molten pool containing a flowable liquid alloy. After cooling, it solidifies to form a weld portion, in which the mass percentage of silicon is controlled between 1.2% and 12%. In this embodiment, the swing amplitude is increased to 0.6 mm compared to Embodiment 1 to adjust the speed and increase its influence on the weld width.

[0054] In this embodiment, one welded part is manufactured using the laser welding method described above, and is marked as 2.

[0055] In this embodiment, the cover plate 110 may also have a structure having an additive layer 112 and an aluminum alloy base material layer 111. When the cover plate 110 is fitted with the flow channel plate substrate 120, the additive layer 112 may be designed on the side closer to the groove 121, or the aluminum alloy base material layer 111 may be designed on the side closer to the groove 121.

[0056] Example 3

[0057] This embodiment uses a ring-shaped laser beam with an inner ring power of 600W and an outer ring power of 1000W. The welding speed is 30mm / s, and the swing amplitude is 1mm. The aluminum alloy base material layer 111 of the cover plate is made of 6-series aluminum alloy, and the flow channel plate substrate is made of 3-series aluminum alloy. A multi-silicon material is applied at the joint between the side wall 113 and the second welding wall 122. The main components of the multi-silicon material include Al and Si, with Si having a mass percentage range of 5-10%. The total height of the multi-silicon material coating is controlled between 0.3-0.9mm. The flow channel plate substrate is made of 3-series aluminum alloy. The welding steps are the same as in Embodiment 1. One welded part is completed and marked as 3.

[0058] Example 4

[0059] This embodiment serves as a control group for Embodiment 2. The difference from Embodiment 2 is that the outer ring power of the welding laser beam is increased to 1500W to analyze the effect of the control outer ring power on welding performance. This embodiment welds one workpiece, labeled 4.

[0060] Appendix Figure 8 The figure shows a metallographic diagram of the weld seam of welded part 4. As can be seen from the figure, the welded part in this embodiment has no weld seam cracks, about 3 pores with small diameters, and the surface structure of the welded part is relatively uniform with no significant difference between light and dark areas.

[0061] Appendix Figure 6 This corresponds to the metallographic diagram of the weld seam of welded component 2 in Example 2, attached. Figure 8A metallographic diagram of the weld seam of welded component 4 is attached. Figure 8 The metallographic diagram of the weld seam of the welded component 4 shows a reduction in the number of pores and a decrease in pore diameter. This indirectly reflects that increasing the outer ring power to 1500W can significantly improve the porosity defect.

[0062] Comparative Example

[0063] This embodiment is an implementation without adjusting the mass percentage of each element in the welded part. It uses the same welding process as in Embodiment 3, with a welding speed of 30 mm / s, a ring laser beam, an inner ring power of 600 W, an outer ring power of 1000 W, and a swing amplitude of 1 mm. A 6-series aluminum alloy cover plate is riveted to a 3-series aluminum alloy flow channel plate substrate and secured with tooling. The ring laser beam irradiates above the joint between the side wall 113 of the cover plate 110 and the second welded part 122 of the flow channel plate substrate 120. After cooling and solidification, one welded part is manufactured, labeled as 5. A comparative explanation is given of the improvement in weld cracking caused by laser welding processes that improve the silicon content in the welded part. (Appendix) Figure 9 Metallographic diagram of weld seam in weldment 5 is attached. Figure 9 There are obvious cracks in the middle weld, and about 6 obvious pores, with 2 larger pores in the lower right corner.

[0064] In Example 3, a polysilicon material is applied to the joint between the sidewall 113 and the second weld wall 122, thus improving the mass percentage of silicon in the weld. The welded part is manufactured using the same welding process. Figure 7 This is a metallographic diagram of weld seam 3 of the welded component. Figure 7 As can be seen, there is no weld cracking, only 3 small pores. In the comparative example where the mass percentage of silicon in the weld was not improved, weld 5 showed more obvious cracking, all accompanied by larger pores. Therefore, adding multi-silicon material at the joint between the side wall 113 and the second weld wall 122 significantly improves the weld cracking by increasing the proportion of silicon in the weld.

[0065] The table below shows the metallographic schematic data of each welded component in each embodiment and the corresponding figure numbers.

[0066] Table 2. Statistics of metallographic schematic diagrams of welded parts in Examples 1-4 and Comparative Examples, and corresponding figure numbers.

[0067]

[0068] The statistical data in the table above shows that the weld of welded part 5 in the comparative example has obvious cracks. In Examples 1, 2, 3 and 4, after improving the mass percentage of silicon in the welded part, no weld cracks were found.

[0069] Appendix Figure 5 This is a metallographic schematic diagram of the weld joint of welded component 1 in Example 1. Figure 5 The results show that weldment 1 has 5 pores, and the overall welding performance is within an acceptable range. Comparing the metallographic diagram of weldment 2, the welding speed of Example 2 is 20 mm / s, which is higher than the 10 mm / s of Example 1. The weld pool width is 3.44 mm and the weld pool depth is 2.5 mm, both of which are lower than the weld pool width and depth of Example 1. Similarly, Example 3 has a welding speed of 30 mm / s, a weld pool width of 2.5 mm, and a weld pool depth of 2.22 mm. Its welding speed is higher than that of Example 2, while the average weld pool width and average weld pool depth are lower. Adjusting the welding speed adjusts the weld pool width and depth, thereby comprehensively adjusting the mass percentage of each element in the weld, controlling the grain refinement degree in the weld within the non-crack-sensitive area, and simultaneously adjusting the size and shape of the weld to maintain good welding performance.

[0070] The above examples illustrate the principles and implementation methods of the invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the invention.

Claims

1. A laser welding method for aluminum alloys, characterized in that, Includes the following steps: A first part (1) is provided, the first part (1) having a wall portion (11). A second part (2) is provided, the second part (2) having a first weld wall (21), the wall portion (11) and / or the first weld wall (21) comprising a polysilicon material, the polysilicon material comprising 85%-95% by mass Al and 5%-15% by mass Si; one of the first part (1) and the second part (2) comprises a first base material and the other part comprises a first base material or a second base material, the first base material and the second base material being aluminum alloys, the first base material comprising 0.2%-1.8% by mass Si, 0.2%-3% by mass Mg, and 95.2%-99.6% by mass Al, the second base material comprising 0.05%-1.8% by mass Mn and 98.2%-99.95% by mass Al; The first weld wall (21) is joined to the wall portion (11), and the first part (1) and the second part (2) are laser welded together.

2. A laser welding method for aluminum alloys, characterized in that, Includes the following steps: A first part (1) is provided, the first part (1) having a wall portion (11). A second part (2) is provided, the second part (2) having a first weld wall (21), the wall portion (11) and / or the first weld wall (21) comprising a polysilicon material, the polysilicon material comprising 85%-95% by mass Al and 5%-15% by mass Si; one of the first part (1) and the second part (2) comprises a first base material and the other part comprises a first base material or a second base material, the first base material and the second base material being aluminum alloys, the first base material comprising 0.2%-1.8% by mass Si, 0.2%-3% by mass Mg, and 95.2%-99.6% by mass Al, the second base material comprising 0.05%-1.8% by mass Mn and 98.2%-99.95% by mass Al; The first weld wall (21) is joined to the wall portion (11), the first weld wall (21) and the wall portion (11) have a gap n, and the portion of the wall portion (11) that joins the first weld wall (21) in the height direction has a height s, and the gap n is controlled to be ≤0.1s; the first part (1) and the second part (2) are laser welded.

3. The aluminum alloy laser welding method according to claim 1 or 2, characterized in that: The second part (2) includes a first aluminum alloy plate having an additive layer (112) and an aluminum alloy base material layer (111). The aluminum alloy base material layer (111) includes the first base material or the second base material. The multi-silicon material includes the additive layer (112). The main components of the additive layer (112) include Al and Si, wherein the mass percentage of Si is 5% to 7%. The additive layer (112) and the aluminum alloy base material layer (111) are stacked along the height direction of the first aluminum alloy plate. The additive layer (112) and the aluminum alloy base material layer (111) are connected along the sidewalls of the first aluminum alloy plate along the height direction to form at least a portion of the first welded wall (21). The gap n is controlled to be ≤0.5mm.

4. The aluminum alloy laser welding method according to claim 1 or 2, characterized in that: A multi-silicon material is applied to the mating area (3) between the wall (11) and the first welded wall (21); the main component of the multi-silicon material is Al-xSi, where x is the mass percentage of Si element and the range of x is between 5% and 10%. The main component of the polysilicon material includes 5% to 7% Mg by mass.

5. The aluminum alloy laser welding method according to any one of claims 1-4, characterized in that: A single-spot laser beam is used to irradiate the area (3) where the wall (11) and the first welding wall (21) are joined. The diameter of the single-spot laser beam is controlled between 2 and 4 mm, the power range is controlled between 900 and 2000 W, and the laser welding speed is controlled between 10 and 40 mm / s.

6. The aluminum alloy laser welding method according to any one of claims 1-4, characterized in that, A ring-shaped laser beam is used to irradiate the area (3) above the mating part (11) and the first welding wall (21). The inner ring power range of the ring-shaped laser beam is controlled between 400 and 600W, the inner ring power range of the ring-shaped laser beam is controlled between 1000 and 1500W, the laser welding speed is controlled between 20 and 30 mm / s, and the swing amplitude is controlled between 0.5 and 1 mm.

7. The aluminum alloy laser welding method according to any one of claims 1-4, characterized in that: The total height of the first welded wall (21) is a, and the total height of the polysilicon material is b, wherein b / a ranges from 10% to 30%.

8. The aluminum alloy laser welding method according to claim 3, characterized in that: The first aluminum alloy plate has a first aluminum alloy base layer and a second aluminum alloy base layer. The additive layer (112) is disposed between the first aluminum alloy base layer and the second aluminum alloy base layer. The first aluminum alloy base layer, the second aluminum alloy base layer, and the additive layer (112) are connected to the side wall in the height direction of the first aluminum alloy plate to form the first welded wall (21).

9. The aluminum alloy laser welding method according to any one of 1-4, characterized in that: The first part (1) is a flow channel plate substrate (120), which has a groove (121), a second welding wall (122), and a connecting platform (123). The wall portion (11) is located on the second welding wall (122), the connecting platform (123) is connected to the second welding wall (122), and the connecting platform (123) is connected to the wall of the groove (121). The second part (2) is a cover plate (110), and the first welding wall (21) is located on the side wall portion (113) of the cover plate (110). In the step "connecting the first welding wall (21) with the wall portion (11), the second welding wall (122) is partially or completely connected with the side wall portion (113) by laser welding.

10. The aluminum alloy laser welding method according to any one of claims 1-4, characterized in that: The first component (1) is a first substrate (300), which has a recess (301), a first platform (302), and a third welding wall (303). The wall portion (11) is located on the third welding wall (303), and the third welding wall (303) is connected to the first platform (302). The wall of the recess (301) is connected to the first platform (302). The second component (2) is a first tube (400), which has an annular portion (401). The connecting wall (21) is located on the annular wall (402) on the outer periphery of the first tube (400). The annular portion (401) is connected to the annular wall (402). In the step of "connecting the first welding wall (21) with the wall portion (11), part or all of the annular wall (402) is connected to the third welding wall (303) by laser welding. The total thickness of the polysilicon material along the direction perpendicular to its height is x, and the total thickness of the annular portion (401) along the direction perpendicular to its height is y, wherein the range of x / y is between 10% and 30%.

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