High-weldability corrosion-resistant 7XXX aluminum alloy profile and preparation method thereof

Abstract

The invention discloses a high-weldability corrosion-resistant 7XXX aluminum alloy profile and a preparation method thereof, and belongs to the technical field of aluminum-zinc-magnesium-copper alloy extruded profiles. The aluminum alloy comprises, by mass, less than or equal to 0.1% of Si, less than or equal to 0.1% of Fe, 0.09%-0.18% of Cu, 0.20%-0.8% of Mn, 1.0%-1.8% of Mg, 0.13%-0.26% of Cr, 4.2%-4.7% of Zn, 0.02%-0.06% of Ti, 0.10%-0.18% of Zr, 0.04%-0.16% of V, 0.02%-0.05% of Ce and the balance Al and other inevitable impurity elements. The aluminum alloy has excellent corrosion resistance and welding performance by strictly limiting the proportion of chemical components and adding Zr and V elements to refine grains, and the problem that an existing 7XXX aluminum alloy is difficult to meet the double requirements of engineering application on material corrosion resistance and welding performance at the same time is solved.

Description

Technical Field

[0001] This invention relates to the field of aluminum-zinc-magnesium-copper alloy extruded profiles, specifically to a highly weldable and corrosion-resistant 7XXX aluminum alloy profile and its preparation method. Background Technology

[0002] 7XXX aluminum alloy, as an ultra-high strength and lightweight material, is widely used in high-tech fields such as aerospace and rail transportation due to its excellent specific strength and specific stiffness. In the aerospace field, extruded profiles of this alloy are often used in aircraft frames, bulkhead structures, and landing gear components, which can significantly reduce fuselage weight and improve fuel efficiency. In rail transportation, it is suitable for high-speed train body frames, balancing safety and lightweight requirements. In addition, its application in high-end sports equipment and precision mechanical components is also increasing.

[0003] With the increasing demands for material performance in the industrial sector, the market demand for 7XXX aluminum alloy extruded profiles continues to grow. However, this type of alloy has an inherent defect of poor corrosion resistance, which has long constrained the improvement of its reliability. At the same time, in the process of gas shielded arc welding (such as MIG and TIG), 7XXX aluminum alloys also face the technical bottleneck of poor weldability, and there is an inherent contradiction between corrosion resistance and fusion welding effect, making it difficult to simultaneously meet the dual requirements of corrosion resistance and weldability for engineering applications.

[0004] Therefore, it is necessary to provide a highly weldable and corrosion-resistant 7XXX aluminum alloy profile and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a highly weldable and corrosion-resistant 7XXX aluminum alloy profile and its preparation method, so as to solve the problem that existing 7XXX aluminum alloys cannot simultaneously meet the dual requirements of corrosion resistance and weldability for engineering applications.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A highly weldable and corrosion-resistant 7XXX aluminum alloy profile, by mass percentage, comprises: Si≤0.1%, Fe≤0.1%, Cu: 0.09~0.18%, Mn: 0.20~0.8%, Mg: 1.0~1.8%, Cr: 0.13~0.26%, Zn: 4.2~4.7%, Ti: 0.02~0.06%, Zr: 0.10~0.18%, V: 0.04~0.16%, Ce: 0.02~0.05%, with the remainder being Al and other unavoidable impurity elements.

[0008] Furthermore, the total content of the impurity elements is ≤0.10%, wherein the content of a single impurity element is ≤0.05%.

[0009] The preparation method of a highly weldable and corrosion-resistant 7XXX aluminum alloy profile as described above includes the following steps:

[0010] S1, Ingredients

[0011] High-purity aluminum ingots with a purity ≥99.85%, pure magnesium ingots with a purity ≥99.95%, and zinc ingots with a purity ≥99.995% are used. Si, Mn, Cr, Zr, Cu, and V are added in the form of corresponding aluminum-based master alloys.

[0012] S2, Smelting

[0013] Add the raw materials from step S1 to the melting furnace in the order of refractory metals or master alloys, heat to 720-760°C and stir electromagnetically until melted, degas and remove slag with sodium-free refining agent, and then adjust the temperature to 740-750°C; after preheating the Al-10%Ce master alloy ingot to 250-300°C, press it into the middle of the melt together with the pure magnesium ingot, and stir after melting;

[0014] S3, degassing and filtration

[0015] In step 2, high-purity Ar gas is used for rotary blowing to remove gas during the stirring process, with a rotor speed of 500-800 rpm; online three-stage filtration is used to control the size of inclusions to ≤5μm;

[0016] S4, Casting

[0017] After step 3 is completed, it is cast at a temperature of 690–720℃ and then cooled uniformly to obtain the desired product. 178–259 mm round ingots;

[0018] S5, Homogenization

[0019] The circular ingot in step S4 is subjected to a cycle of holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times.

[0020] S6, extrusion

[0021] The homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating, and the entire ingot is extruded. The extrusion outlet temperature of the profile is 478~488℃, and it is cooled after extrusion.

[0022] S7, stretching

[0023] The extruded profiles are then subjected to stretching treatment, with a stretching rate in the range of 0.5% to 1.5%.

[0024] S8, Timeliness

[0025] The profile after the stretching treatment in step S7 is subjected to a three-stage treatment: pre-aging at 120℃ for 8 hours, regression at 180℃ for 1 hour, and final aging at 100℃ for 24 hours.

[0026] S9, Welding

[0027] The laser-MIG composite welding process is used on the aged profiles in step S8, and welding is completed with pretreatment and specific welding parameters.

[0028] Furthermore, in step S2, the aluminum-based master alloy is at least one of Al-12%Si, Al-10%Mn, Al-5%Cr, Al-5%Zr, Al-50%Cu, and Al-10%V; the stirring method is mechanical stirring or electromagnetic stirring, and the stirring time is not less than 20 minutes.

[0029] Furthermore, in step S3, the high-purity Ar gas has a purity of ≥99.999%, and the bubbles formed by the spraying are small and evenly distributed.

[0030] Furthermore, in step S9, the pretreatment involves removing the surface oxide film with a stainless steel wire brush and then wiping it clean with acetone or alcohol; and preheating the weldment uniformly to 70-100°C using a flame gun.

[0031] Furthermore, in step S9, the laser power is 3.5 to 4.5 kW, the spot diameter is 0.3 to 0.4 mm, and the defocusing amount is -2 to -4 mm.

[0032] Furthermore, in step S9, a dual-pulse MIG welding mode is adopted, with a current of 150-180A, a wire feed speed of 6.0-7.5m / min, and a welding wire size of ER5356 / φ1.2mm.

[0033] Furthermore, in step S9, the filament spacing in the coordinated parameters of the laser and the MIG arc is 1.5–2.5 mm, the welding speed is 1.8–2.5 m / min, and the protective gas is He(50%) + Ar(50%) with a gas flow rate of 25–30 L / min.

[0034] Furthermore, in step S9, after welding, the material is slowly cooled to room temperature at a cooling rate of 20-30°C / h.

[0035] The present invention has the following beneficial effects:

[0036] 1. This invention, by strictly limiting the chemical composition ratio and adding Zr and V elements to refine the grains, enables the aluminum alloy to have excellent corrosion resistance and weldability, thus solving the problem that existing 7XXX aluminum alloys cannot simultaneously meet the dual requirements of corrosion resistance and weldability for engineering applications.

[0037] 2. The homogenization treatment after casting in this invention adopts the homogenization treatment process of "isothermal treatment + cyclic quenching": heat treatment at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, so that the η phase (MgZn2) at the grain boundary is discretized and distributed, reducing the depth of intergranular corrosion, and eliminating segregation at the same time.

[0038] 3. The aging process of aluminum alloy profiles of the present invention is developed into a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)", which results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0039] 4. The welding process of this invention adopts an innovative "laser-MIG composite welding" process, which reduces heat input and improves the weld strength coefficient. It is suitable for rail transit structural components, especially main load-bearing welded structural components. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the corrosion depth of the profiles prepared in Examples 1-5 and Comparative Examples 1-3 of the present invention after 1500 hours of neutral salt spray corrosion.

[0041] Figure 2 This is a schematic diagram showing the intergranular corrosion depth of the profiles prepared in Examples 1-5 and Comparative Examples 1-3 of the present invention.

[0042] Figure 3 This is a schematic diagram of the enhanced precipitate distribution after aging in Example 2 of the present invention. Detailed Implementation

[0043] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0044] This invention provides a highly weldable and corrosion-resistant 7XXX aluminum alloy profile, composed of the following components by mass percentage: Si≤0.1%, Fe≤0.1%, Cu: 0.09-0.18%, Mn: 0.20-0.8%, Mg: 1.0-1.8%, Cr: 0.13-0.26%, Zn: 4.2-4.7%, Ti: 0.02-0.06%, Zr: 0.10-0.18%, V: 0.04-0.16%, Ce: 0.02-0.05%, with other individual impurities ≤0.05%, total impurities ≤0.10%, and the balance being Al.

[0045] A method for preparing a highly weldable and corrosion-resistant 7XXX aluminum alloy profile, comprising the following steps:

[0046] S1: The alloying is made according to the mass percentage of the alloying elements. Specifically, high-purity aluminum ingots (≥99.85% Al), 99.95% or more pure magnesium ingots, and 99.995% or more zinc ingots are added. The remaining elements are added in the form of aluminum-based master alloys (such as Al-12%Si, Al-10%Mn, Al-5%Cr, Al-5%Zr, Al-50%Cu, Al-10%V). The addition of waste or recycled aluminum is prohibited.

[0047] S2: Melting. Specifically, the prepared raw materials are added to the melting furnace in sequence and heated to 720–760℃. First, the refractory metal or master alloy is added and electromagnetically stirred. After melting, it is refined, degassed, and slag is removed using a sodium-free refining agent. The temperature is then adjusted to 740–750℃. The calculated weight of the Al-10%Ce master alloy ingot is placed in a preheating furnace (250–300℃) for thorough preheating to remove surface moisture and prevent the introduction of gas and splashing. Using a bell jar, the preheated Al-10%Ce master alloy and pure magnesium ingot are pressed together into the center of the melt and moved slowly to ensure complete melting at the bottom. It is crucial to avoid directly throwing them onto the surface of the molten pool. After complete melting, mechanical or electromagnetic stirring is immediately performed for at least 20 minutes to ensure uniform composition.

[0048] S3: Degassing and filtration. Specifically, the degassing process uses high-purity Ar gas for rotary blowing at a rotor speed of 500-800 rpm to ensure the generation of fine, uniformly distributed bubbles, increasing the gas-liquid contact area and contact time, and thoroughly degassing the melt online. Online filtration employs a three-stage filtration system (dual-stage foam ceramic + deep bed) to achieve deep purification of the melt, reducing inclusion size to ≤5μm and decreasing the pore nucleation rate.

[0049] S4: Casting. Specifically, the casting temperature is controlled within the range of 690 to 720°C. The casting process requires rapid and uniform cooling to obtain round ingots with a diameter of ∅178 to 259 mm.

[0050] S5: Homogenization treatment. Specifically, a homogenization process of "isothermal treatment + cyclic quenching" is adopted: heat treatment at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, so that the η phase (MgZn2) at the grain boundary is discretized and distributed, reducing the depth of intergranular corrosion and eliminating segregation.

[0051] S6: Extrusion. Specifically, the homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating. The entire ingot is extruded at a constant temperature and speed, with the extrusion outlet temperature controlled at 480~500℃ and cooled by strong air.

[0052] S7: Stretching, specifically, controlling the stretching rate within the range of 0.5% to 1.5%;

[0053] S8: Aging, specifically, the development of a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)" results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0054] S9: Welding. Extruded profiles are welded using the "laser-MIG composite welding" process.

[0055] Specifically, remove the surface oxide film (Al2O3) with a stainless steel wire brush, then wipe clean with acetone or alcohol. Preheat the workpiece with a flame torch; the preheating temperature should not be too high, usually controlled between 70-100°C. Heating should be uniform to avoid localized overheating. During the welding process, the laser ignites a few milliseconds before the arc, forming a molten pool and keyhole on the workpiece surface (laser power 3.5–4.5 kW, spot diameter 0.3–0.4 mm, defocusing distance -2–-4 mm). The MIG arc then ignites immediately, and the arc is attracted by the plasma and metal vapor generated by the laser, quickly stabilizing near the laser's point of action. Use a dual-pulse MIG welding mode with a current range of 150–180 A, a wire feed speed of 6.0–7.5 m / min, and ER5356 / φ1.2 mm welding wire. For laser and MIG hybrid welding, the parameters for the synergistic part are: laser wire spacing (DLA) 1.5-2.5mm, welding speed 1.8-2.5m / min, using He (50%) + Ar (50%) shielding gas, and gas flow rate 25-30L / min.

[0056] In this invention, optimizing the Zn / Mg ratio reduces the cathodic activity of the η phase (MgZn2) and lowers the pitting corrosion tendency. Zr / Ti microalloying is employed to form nanoscale... Phase pinning at grain boundaries increases the interphase spacing and reduces the depth of intergranular corrosion. The design using low Cu content (0.09-0.18%) and highly purified components extends salt spray corrosion life while reducing... The harmful effects of phases. Strictly controlling ultra-low Fe and Si content reduces oxide film rupture sources. Combined with rare earth elements to purify the melt, it reduces weld porosity and improves weld strength coefficient. Adding rare earth element Ce can refine grains and purify the melt. Ce preferentially segregates at grain boundaries and forms stable compounds with Cu (such as…). Ce blocks Cu grain boundary segregation and reduces intergranular corrosion channels. Ce combines with impurity elements (such as Fe) to form... To reduce the amount of Fe-Al cathode phase, Mn can be added to neutralize the harmful effects of Fe impurities and reduce galvanic corrosion of the Fe-Al phase. Strict control of Fe and Si content (Fe ≤ 0.1%, Si ≤ 0.1%) is essential to prevent the formation of coarse-grained... Harmful phases, etc.

[0057] In this invention, Zr and V elements are added during the casting process. Zirconium forms a very stable... Dispersed phases, their mechanism of action is similar to that of vanadium (grain refinement, inhibition of recrystallization). The combined addition of vanadium and zirconium can form more complex and stable composite precipitates (such as Al, zirconium, and vanadium). ), they are more than a single Alternatively, the Al-V phase has higher thermal stability and can maintain pinning effect even at higher peak welding temperatures, thus extending the improvement effect to a wider HAZ region.

[0058] The present invention employs a three-stage filtration process (two-stage foam ceramic + deep bed) to achieve deep purification of the melt, with inclusion size ≤5μm, thereby reducing the porosity nucleation rate.

[0059] The homogenization process after casting in this invention employs an "isothermal treatment + cyclic quenching" process: holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, to homogenize the grain boundary η phase ( Discretization reduces the depth of intergranular corrosion and eliminates segregation.

[0060] The aging process of aluminum alloy profiles of the present invention is developed into a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)", which results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0061] The welding process of this invention adopts an innovative "laser-MIG composite welding" process, which reduces heat input and improves the weld strength coefficient. It is suitable for rail transit structural components, especially main load-bearing welded structural components.

[0062] This invention achieves excellent corrosion resistance and weldability of aluminum alloys while ensuring sufficient strengthening through strict control of chemical composition ratios, reduction of impurities and gas content, addition of Zr and V elements to refine grains and improve weldability, multiple homogenization treatments, constant temperature and speed extrusion, and innovative welding processes. The extruded profiles of this material have a tensile strength ≥450MPa, a yield strength ≥360MPa, a weld strength coefficient ≥0.8 after welding, and corrosion resistance close to that of 5005 rust-resistant aluminum (salt spray ≥1500h). Furthermore, there is no intergranular corrosion, and the intergranular corrosion is evaluated according to the "GBT7998-2023 Aluminum Alloy Intergranular Corrosion Sensitivity Evaluation Method" standard.

[0063] To make the objectives, technical solutions, and advantages of the embodiments clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below; where no specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed; where no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0064] The following is a detailed description of an embodiment of the preparation method of a highly weldable and corrosion-resistant 7XXX aluminum alloy profile according to the present invention.

[0065] Example 1:

[0066] S1: Ingredients; Si: 0.06%, Fe: 0.07%, Cu: 0.13%, Mn: 0.67%, Mg: 1.3%, Cr: 0.15%, Zn: 4.3%, Ti: 0.03%, Zr: 0.13%, V: 0.15%, Ce: 0.03%, each unavoidable impurity element is less than 0.05%, the total impurity is less than 0.10%, and the balance is Al. The Ti element is added during the casting process through online wire feeding. The addition of scrap or recycled aluminum is prohibited.

[0067] S2: Melting; Add the prepared raw materials to the melting furnace in sequence and heat to 750℃. First add the refractory metal or master alloy and perform electromagnetic stirring. After melting, refine the aluminum alloy melt with a sodium-free refining agent to remove gas and slag, then adjust the temperature to 745℃. Place the calculated weight of the Al-10%Ce master alloy ingot into a preheating furnace (260℃) for thorough preheating to remove surface moisture and prevent the introduction of gas and splashing. Use a bell jar to press the preheated Al-10%Ce master alloy and pure magnesium ingot together into the center of the melt and move it slowly to ensure thorough melting at the bottom. Do not throw it directly onto the surface of the molten pool. After complete melting, immediately perform mechanical or electromagnetic stirring for 25 minutes to ensure uniform composition.

[0068] S3: Degassing and Filtration: The degassing process uses high-purity Ar gas for rotary blowing degassing at a rotor speed of 600 rpm to ensure the generation of fine and uniformly distributed bubbles, increasing the gas-liquid contact area and contact time, and fully degassing the melt online; the online filtration adopts three-stage filtration (double-stage foam ceramic + deep bed) to achieve deep purification of the melt, with inclusion size ≤5μm, reducing the nucleation rate of pores.

[0069] S4: Casting: The casting temperature is controlled within the range of 695 to 715℃. The casting process requires rapid and uniform cooling to obtain round ingots with a diameter of ∅178 to 259 mm.

[0070] S5: Homogenization treatment: A homogenization process of "isothermal treatment + cyclic quenching" is adopted: holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, to make the grain boundary η phase ( Discretization reduces the depth of intergranular corrosion and eliminates segregation.

[0071] S6: Extrusion: The homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating. The entire ingot is extruded at a constant temperature and speed, with the extrusion outlet temperature controlled at 480~490℃ and cooled by strong air.

[0072] S7: Stretching: The stretching rate is 0.5%.

[0073] S8: Aging: Develop a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)", which results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0074] S9: Welding: Extruded profiles are welded using the "laser-MIG composite welding" process.

[0075] Remove the surface oxide film (Al2O3) with a stainless steel wire brush, then wipe clean with acetone or alcohol. Preheat the workpiece with a flame torch, keeping the preheating temperature between 80-100℃. Heating should be uniform to avoid localized overheating. During welding, the laser ignites a few milliseconds before the arc, forming a molten pool and keyhole on the workpiece surface (laser power 4kW, spot diameter 0.35mm, defocusing distance -2.5mm). The MIG arc then ignites immediately, attracting the plasma and metal vapor generated by the laser and quickly stabilizing near the laser's point of action. Use a dual-pulse MIG welding mode with a current range of 160-180A, a wire feed speed of 6.5m / min, and ER5356 / φ1.2mm welding wire. Laser and MIG hybrid welding was performed with the following parameters: laser filament spacing (DLA) 2.0 mm, welding speed 2.1 m / min, and a shielding gas of He (50%) + Ar (50%) with a gas flow rate of 28 L / min.

[0076] Example 2:

[0077] S1: Ingredients; Si: 0.07%, Fe: 0.08%, Cu: 0.12%, Mn: 0.77%, Mg: 1.4%, Cr: 0.14%, Zn: 4.6%, Ti: 0.03%, Zr: 0.14%, V: 0.16%, Ce: 0.03%, each unavoidable impurity element is less than 0.05%, the total impurity is less than 0.10%, and the balance is Al. The Ti element is added during the casting process through online wire feeding. The addition of scrap or recycled aluminum is prohibited.

[0078] S2: Melting; Add the prepared raw materials to the melting furnace in sequence and heat to 755℃. First add the refractory metal or master alloy and perform electromagnetic stirring. After melting, refine the aluminum alloy melt with a sodium-free refining agent to remove gas and slag, then adjust the temperature to 740℃. Place the calculated weight of the Al-10%Ce master alloy ingot into a preheating furnace (270℃) for thorough preheating to remove surface moisture and prevent the introduction of gas and splashing. Use a bell jar to press the preheated Al-10%Ce master alloy and pure magnesium ingot together into the center of the melt and move it slowly to ensure thorough melting at the bottom. Do not throw it directly onto the surface of the molten pool. After complete melting, immediately perform mechanical or electromagnetic stirring for 30 minutes to ensure uniform composition.

[0079] S3: Degassing and Filtration: The degassing process uses high-purity Ar gas for rotary blowing degassing, with a rotor speed of 620 rpm, to ensure the generation of fine and uniformly distributed bubbles, increase the gas-liquid contact area and contact time, and fully degas the melt online; the online filtration adopts three-stage filtration (double-stage foam ceramic + deep bed) to achieve deep purification of the melt, with inclusion size ≤5μm, and reduce the nucleation rate of pores.

[0080] S4: Casting: The casting temperature is controlled within the range of 690 to 710℃. The casting process requires rapid and uniform cooling to obtain round ingots with a diameter of ∅178 to 259 mm.

[0081] S5: Homogenization treatment: A homogenization process of "isothermal treatment + cyclic quenching" is adopted: holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, to make the grain boundary η phase ( Discretization reduces the depth of intergranular corrosion and eliminates segregation.

[0082] S6: Extrusion: The homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating. The entire ingot is extruded at a constant temperature and speed, with the extrusion outlet temperature controlled at 480~490℃ and cooled by strong air.

[0083] S7: Stretching: The stretching rate is 0.6%.

[0084] S8: Aging: Develop a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)", which results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0085] S9: Welding: Extruded profiles are welded using the "laser-MIG composite welding" process.

[0086] Remove the surface oxide film (Al2O3) with a stainless steel wire brush, then wipe clean with acetone or alcohol. Preheat the workpiece with a flame torch, keeping the preheating temperature between 85-100℃. Heating should be uniform to avoid localized overheating. During welding, the laser ignites a few milliseconds before the arc, forming a molten pool and keyhole on the workpiece surface (laser power 4.2kW, spot diameter 0.30mm, defocusing distance -2.6mm). The MIG arc then ignites immediately, attracting the plasma and metal vapor generated by the laser and quickly stabilizing near the laser's point of action. Use a dual-pulse MIG welding mode with a current range of 165-180A, a wire feed speed of 6.6m / min, and ER5356 / φ1.2mm welding wire. Laser and MIG hybrid welding was performed with the following parameters: laser filament spacing (DLA) of 2.1 mm, welding speed of 2.2 m / min, and a shielding gas of He (50%) + Ar (50%) with a gas flow rate of 27 L / min.

[0087] Example 3:

[0088] S1: Ingredients; Si: 0.08%, Fe: 0.08%, Cu: 0.13%, Mn: 0.72%, Mg: 1.43%, Cr: 0.16%, Zn: 4.4%, Ti: 0.03%, Zr: 0.15%, V: 0.14%, Ce: 0.04%, each unavoidable impurity element is less than 0.05%, the total impurity is less than 0.10%, and the balance is Al. The Ti element is added during the casting process through online wire feeding. The addition of scrap or recycled aluminum is prohibited.

[0089] S2: Melting; Add the prepared raw materials to the melting furnace in sequence and heat to 755℃. First add the refractory metal or master alloy and perform electromagnetic stirring. After melting, refine the aluminum alloy melt with a sodium-free refining agent to remove gas and slag, then adjust the temperature to 745℃. Place the calculated weight of the Al-10%Ce master alloy ingot into a preheating furnace (260℃) for thorough preheating to remove surface moisture and prevent the introduction of gas and splashing. Use a bell jar to press the preheated Al-10%Ce master alloy and pure magnesium ingot together into the center of the melt and move it slowly to ensure thorough melting at the bottom. Do not throw it directly into the surface of the molten pool. After complete melting, immediately perform mechanical or electromagnetic stirring for 29 minutes to ensure uniform composition.

[0090] S3: Degassing and Filtration: The degassing process uses high-purity Ar gas for rotary blowing degassing with a rotor speed of 610 rpm to ensure the generation of fine and uniformly distributed bubbles, increasing the gas-liquid contact area and contact time, and fully degassing the melt online; the online filtration adopts three-stage filtration (double-stage foam ceramic + deep bed) to achieve deep purification of the melt, with inclusion size ≤5μm, reducing the nucleation rate of pores.

[0091] S4: Casting: The casting temperature is controlled within the range of 698 to 718℃. The casting process requires rapid and uniform cooling to obtain round ingots with a diameter of ∅178 to 259mm.

[0092] S5: Homogenization treatment: A homogenization process of "isothermal treatment + cyclic quenching" is adopted: holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, to make the grain boundary η phase ( Discretization reduces the depth of intergranular corrosion and eliminates segregation.

[0093] S6: Extrusion: The homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating. The entire ingot is extruded at a constant temperature and speed, with the extrusion outlet temperature controlled at 478~488℃ and cooled by strong air.

[0094] S7: Stretching: The stretching rate is 0.55%.

[0095] S8: Aging: Develop a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)", which results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0096] S9: Welding: Extruded profiles are welded using the "laser-MIG composite welding" process.

[0097] Remove the surface oxide film (Al2O3) with a stainless steel wire brush, then wipe clean with acetone or alcohol. Preheat the workpiece with a flame torch, keeping the preheating temperature between 86-100℃. Heating should be uniform to avoid localized overheating. During welding, the laser ignites a few milliseconds before the arc, forming a molten pool and keyhole on the workpiece surface (laser power 4.3kW, spot diameter 0.37mm, defocusing distance -2.6mm). The MIG arc then ignites immediately, attracting the plasma and metal vapor generated by the laser and quickly stabilizing near the laser's point of action. Use a dual-pulse MIG welding mode with a current range of 168-175A, a wire feed speed of 6.8m / min, and ER5356 / φ1.2mm welding wire. Laser and MIG hybrid welding was performed with the following parameters: laser filament spacing (DLA) of 2.2 mm, welding speed of 2.0 m / min, and a shielding gas of He (50%) + Ar (50%) with a gas flow rate of 29 L / min.

[0098] Example 4:

[0099] S1: Ingredients; Si: 0.08%, Fe: 0.09%, Cu: 0.13%, Mn: 0.68%, Mg: 1.46%, Cr: 0.14%, Zn: 4.5%, Ti: 0.03%, Zr: 0.15%, V: 0.05%, Ce: 0.04%, each unavoidable impurity element is less than 0.05%, the total impurity is less than 0.10%, and the balance is Al. The Ti element is added during the casting process through online wire feeding. The addition of scrap or recycled aluminum is prohibited.

[0100] S2: Melting; Add the prepared raw materials to the melting furnace in sequence and heat to 755℃. First add the refractory metal or master alloy and perform electromagnetic stirring. After melting, refine the aluminum alloy melt with a sodium-free refining agent to remove gas and slag, then adjust the temperature to 745℃. Place the calculated weight of the Al-10%Ce master alloy ingot into a preheating furnace (270℃) for thorough preheating to remove surface moisture and prevent the introduction of gas and splashing. Use a bell jar to press the preheated Al-10%Ce master alloy and pure magnesium ingot together into the center of the melt and move it slowly to ensure thorough melting at the bottom. Do not throw it directly onto the surface of the molten pool. After complete melting, immediately perform mechanical or electromagnetic stirring for 23 minutes to ensure uniform composition.

[0101] S3: Degassing and Filtration: The degassing process uses high-purity Ar gas for rotary blowing degassing, with a rotor speed of 590 rpm, to ensure the generation of fine and uniformly distributed bubbles, increase the gas-liquid contact area and contact time, and fully degas the melt online; the online filtration adopts three-stage filtration (double-stage foam ceramic + deep bed) to achieve deep purification of the melt, with inclusion size ≤5μm, and reduce the nucleation rate of pores.

[0102] S4: Casting: The casting temperature is controlled within the range of 697 to 717℃. The casting process requires rapid and uniform cooling to obtain round ingots with a diameter of ∅178 to 259 mm.

[0103] S5: Homogenization treatment: A homogenization process of "isothermal treatment + cyclic quenching" is adopted: holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, to make the grain boundary η phase ( Discretization reduces the depth of intergranular corrosion and eliminates segregation.

[0104] S6: Extrusion: The homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating. The entire ingot is extruded at a constant temperature and speed, with the extrusion outlet temperature controlled at 480~490℃ and cooled by strong air.

[0105] S7: Tensile: Tensile rate is 0.65%.

[0106] S8: Aging: Develop a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)", which results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0107] S9: Welding: Extruded profiles are welded using the "laser-MIG composite welding" process.

[0108] Remove the surface oxide film (Al2O3) with a stainless steel wire brush, then wipe clean with acetone or alcohol. Preheat the workpiece with a flame torch, keeping the preheating temperature between 90-100℃. Heating should be uniform to avoid localized overheating. During welding, the laser ignites a few milliseconds before the arc, forming a molten pool and keyhole on the workpiece surface (laser power 4.6kW, spot diameter 0.38mm, defocusing distance -2.7mm). The MIG arc then ignites immediately, attracting the plasma and metal vapor generated by the laser and quickly stabilizing near the laser's point of action. Use a dual-pulse MIG welding mode with a current range of 170-180A, a wire feed speed of 6.8m / min, and ER5356 / φ1.2mm welding wire. Laser and MIG hybrid welding was performed with the following parameters: laser filament spacing (DLA) of 2.4 mm, welding speed of 2.3 m / min, and a shielding gas of He (50%) + Ar (50%) with a gas flow rate of 25 L / min.

[0109] Example 5:

[0110] S1: Ingredients; Si: 0.07%, Fe: 0.09%, Cu: 0.14%, Mn: 0.66%, Mg: 1.5%, Cr: 0.15%, Zn: 4.4%, Ti: 0.03%, Zr: 0.15%, V: 0.05%, Ce: 0.04%, each unavoidable impurity element is less than 0.05%, the total impurity is less than 0.10%, the balance is Al, among which Ti element is added in the casting process through online wire feeding, and the addition of scrap or recycled aluminum is prohibited.

[0111] S2: Melting; Add the prepared raw materials to the melting furnace in sequence and heat to 760℃. First add the refractory metal or master alloy and perform electromagnetic stirring. After melting, refine the aluminum alloy melt with a sodium-free refining agent to remove gas and slag, then adjust the temperature to 740℃. Place the calculated weight of the Al-10%Ce master alloy ingot into a preheating furnace (290℃) for thorough preheating to remove surface moisture and prevent the introduction of gas and splashing. Use a bell jar to press the preheated Al-10%Ce master alloy and pure magnesium ingot together into the center of the melt and move it slowly to ensure thorough melting at the bottom. Do not throw it directly into the surface of the molten pool. After complete melting, immediately perform mechanical or electromagnetic stirring for 26 minutes to ensure uniform composition.

[0112] S3: Degassing and Filtration: The degassing process uses high-purity Ar gas for rotary blowing degassing at a rotor speed of 600 rpm to ensure the generation of fine and uniformly distributed bubbles, increasing the gas-liquid contact area and contact time, and fully degassing the melt online; the online filtration adopts three-stage filtration (double-stage foam ceramic + deep bed) to achieve deep purification of the melt, with inclusion size ≤5μm, reducing the nucleation rate of pores.

[0113] S4: Casting: The casting temperature is controlled within the range of 690 to 710℃. The casting process requires rapid and uniform cooling to obtain round ingots with a diameter of ∅178 to 259 mm.

[0114] S5: Homogenization treatment: A homogenization process of "isothermal treatment + cyclic quenching" is adopted: holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, to make the grain boundary η phase ( Discretization reduces the depth of intergranular corrosion and eliminates segregation.

[0115] S6: Extrusion: The homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating. The entire ingot is extruded at a constant temperature and speed, with the extrusion outlet temperature controlled at 480~490℃ and cooled by strong air.

[0116] S7: Tensile: Tensile rate is 0.65%.

[0117] S8: Aging: Develop a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)", which results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0118] S9: Welding: Extruded profiles are welded using the "laser-MIG composite welding" process.

[0119] Remove the surface oxide film (Al2O3) with a stainless steel wire brush, then wipe clean with acetone or alcohol. Preheat the workpiece with a flame torch, keeping the preheating temperature between 80-100℃. Heating should be uniform to avoid localized overheating. During welding, the laser ignites a few milliseconds before the arc, forming a molten pool and keyhole on the workpiece surface (laser power 4.8kW, spot diameter 0.37mm, defocusing distance -2.9mm). The MIG arc then ignites immediately, attracting the plasma and metal vapor generated by the laser and quickly stabilizing near the laser's point of action. Use a dual-pulse MIG welding mode with a current range of 160-170A, a wire feed speed of 6.1m / min, and ER5356 / φ1.2mm welding wire. Laser and MIG hybrid welding was performed with the following parameters: laser filament spacing (DLA) 2.0 mm, welding speed 2.7 m / min, and a shielding gas of He (50%) + Ar (50%) with a gas flow rate of 25 L / min.

[0120] Comparative Example 1:

[0121] S1: Ingredients; Si: 0.09%, Fe: 0.09%, Cu: 0.18%, Mn: 0.32%, Mg: 1.43%, Cr: 0.15%, Zn: 4.35%, Ti: 0.03%, Zr: 0.13%, Ce: 0.03%, each unavoidable impurity element is less than 0.05%, the total impurity is less than 0.10%, and the balance is Al. The Ti element is added during the casting process through online wire feeding. The addition of scrap or recycled aluminum is prohibited.

[0122] S2: Melting; Add the prepared raw materials to the melting furnace in sequence and heat to 760℃. First add the refractory metal or master alloy and perform electromagnetic stirring. After melting, refine the aluminum alloy melt with a sodium-free refining agent to remove gas and slag, then adjust the temperature to 750℃. Place the calculated weight of the Al-10%Ce master alloy ingot into a preheating furnace (250℃) for thorough preheating to remove surface moisture and prevent the introduction of gas and splashing. Use a bell jar to press the preheated Al-10%Ce master alloy and pure magnesium ingot together into the center of the melt and move it slowly to ensure thorough melting at the bottom. Do not throw it directly onto the surface of the molten pool. After complete melting, immediately perform mechanical or electromagnetic stirring for 25 minutes to ensure uniform composition.

[0123] S3: Degassing and Filtration: The degassing process uses high-purity Ar gas for rotary blowing degassing at a rotor speed of 600 rpm to ensure the generation of fine and uniformly distributed bubbles, increasing the gas-liquid contact area and contact time, and fully degassing the melt online; the online filtration adopts three-stage filtration (double-stage foam ceramic + deep bed) to achieve deep purification of the melt, with inclusion size ≤5μm, reducing the nucleation rate of pores.

[0124] S4: Casting: The casting temperature is controlled within the range of 690 to 710℃. The casting process requires rapid and uniform cooling to obtain round ingots with a diameter of ∅178 to 259 mm.

[0125] S5: Homogenization treatment: A homogenization process of "isothermal treatment + cyclic quenching" is adopted: holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, to make the grain boundary η phase ( Discretization reduces the depth of intergranular corrosion and eliminates segregation.

[0126] S6: Extrusion: The homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating. The entire round cast bar is extruded at a constant temperature and speed, with the extrusion outlet temperature controlled at 480~490℃ and cooled by strong air.

[0127] S7: Stretching: The stretching rate is 0.8%.

[0128] S8: Aging: Develop a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)", which results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0129] S9: Welding: Extruded profiles are welded using the "laser-MIG composite welding" process.

[0130] Remove the surface oxide film (Al2O3) with a stainless steel wire brush, then wipe clean with acetone or alcohol. Preheat the workpiece with a flame torch, keeping the preheating temperature between 80-90℃. Heating should be uniform to avoid localized overheating. During welding, the laser ignites a few milliseconds before the arc, forming a molten pool and keyhole on the workpiece surface (laser power 4.1kW, spot diameter 0.37mm, defocusing distance -2.8mm). The MIG arc then ignites immediately, attracting the plasma and metal vapor generated by the laser and quickly stabilizing near the laser's point of action. Use a dual-pulse MIG welding mode with a current range of 165-175A, a wire feed speed of 6.4m / min, and ER5356 / φ1.2mm welding wire. Laser and MIG hybrid welding was performed with the following parameters: laser filament spacing (DLA) of 2.3 mm, welding speed of 2.6 m / min, and a shielding gas of He (50%) + Ar (50%) with a gas flow rate of 25 L / min.

[0131] Comparative Example 2:

[0132] S1: Ingredients; Si: 0.09%, Fe: 0.09%, Cu: 0.17%, Mn: 0.40%, Mg: 1.44%, Cr: 0.16%, Zn: 4.46%, Ti: 0.02%, Zr: 0.14%, V: 0.15%, Ce: 0.03%, each unavoidable impurity element is less than 0.05%, the total impurity is less than 0.10%, and the balance is Al. The Ti element is added during the casting process through online wire feeding. The addition of scrap or recycled aluminum is prohibited.

[0133] S2: Melting; Add the prepared raw materials to the melting furnace in sequence and heat to 760℃. First add the refractory metal or master alloy and perform electromagnetic stirring. After melting, refine the aluminum alloy melt with a sodium-free refining agent to remove gas and slag, then adjust the temperature to 750℃. Place the calculated weight of the Al-10%Ce master alloy ingot into a preheating furnace (250℃) for thorough preheating to remove surface moisture and prevent the introduction of gas and splashing. Use a bell jar to press the preheated Al-10%Ce master alloy and pure magnesium ingot together into the center of the melt and move it slowly to ensure thorough melting at the bottom. Do not throw it directly onto the surface of the molten pool. After complete melting, immediately perform mechanical or electromagnetic stirring for 25 minutes to ensure uniform composition.

[0134] S3: Degassing and Filtration: The degassing process uses high-purity Ar gas for rotary blowing at a rotor speed of 610 rpm to ensure the generation of fine, uniformly distributed bubbles, increasing the gas-liquid contact area and contact time, and thoroughly degassing the melt online. Online filtration employs a three-stage filtration system (dual-stage foam ceramic + deep bed) to achieve deep purification of the melt, reducing inclusion size to ≤5μm and decreasing the pore nucleation rate.

[0135] S4: Casting: The casting temperature is controlled within the range of 690–710℃. Rapid and uniform cooling is required during the casting process to obtain… 178-259mm round ingots.

[0136] S5: Homogenization treatment: A homogenization process of "isothermal treatment + cyclic quenching" is adopted: holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, to make the grain boundary η phase ( Discretization reduces the depth of intergranular corrosion and eliminates segregation.

[0137] S6: Extrusion: The homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating. The entire round cast bar is extruded at a constant temperature and speed, with the extrusion outlet temperature controlled at 480~490℃ and cooled by strong air.

[0138] S7: Stretching: The stretching rate is 0.7%.

[0139] S8: Aging: Develop a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)", which results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0140] S9: Welding: Extruded profiles are welded using the MIG welding process.

[0141] Remove the surface oxide film (Al2O3) with a stainless steel wire brush, then wipe clean with acetone or alcohol. Preheat the workpiece with a flame torch; the preheating temperature should not be too high, controlled between 85-95℃, and heating should be uniform to avoid localized overheating. 1.2mm ER5356 welding wire, pure argon shielding gas, gas flow rate of 20L / min, welding current of 115A, welding speed of 50cm / min, and welding extension of 12mm.

[0142] Comparative Example 3:

[0143] S1: Ingredients; Si: 0.15%, Fe: 0.14%, Cu: 0.17%, Mn: 0.38%, Mg: 1.46%, Cr: 0.15%, Zn: 4.51%, Ti: 0.02%, Zr: 0.14%, Ce: 0.04%, each unavoidable impurity element is less than 0.05%, the total impurity is less than 0.10%, and the balance is Al. The Ti element is added during the casting process through online wire feeding. The addition of scrap or recycled aluminum is prohibited.

[0144] S2: Melting; Add the prepared raw materials to the melting furnace in sequence and heat to 760℃. First add the refractory metal or master alloy and perform electromagnetic stirring. After melting, refine the aluminum alloy melt with a sodium-free refining agent to remove gas and slag, then adjust the temperature to 745℃. Place the calculated weight of the Al-10%Ce master alloy ingot into a preheating furnace (250℃) for thorough preheating to remove surface moisture and prevent the introduction of gas and splashing. Use a bell jar to press the preheated Al-10%Ce master alloy and pure magnesium ingot together into the center of the melt and move it slowly to ensure thorough melting at the bottom. Do not throw it directly onto the surface of the molten pool. After complete melting, immediately perform mechanical or electromagnetic stirring for 25 minutes to ensure uniform composition.

[0145] S3: Degassing and Filtration: The degassing process uses high-purity Ar gas for rotary blowing degassing with a rotor speed of 610 rpm to ensure the generation of fine and uniformly distributed bubbles, increasing the gas-liquid contact area and contact time, and fully degassing the melt online; the online filtration adopts three-stage filtration (double-stage foam ceramic + deep bed) to achieve deep purification of the melt, with inclusion size ≤5μm, reducing the nucleation rate of pores.

[0146] S4: Casting: The casting temperature is controlled within the range of 690–715℃. Rapid and uniform cooling is required during the casting process to obtain… 178-259mm round ingots.

[0147] S5: Homogenization treatment: A homogenization process of "isothermal treatment + cyclic quenching" is adopted: holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times, to make the grain boundary η phase ( Discretization reduces the depth of intergranular corrosion and eliminates segregation.

[0148] S6: Extrusion: The homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating. The entire round cast bar is extruded at a constant temperature and speed, with the extrusion outlet temperature controlled at 480~490℃ and cooled by strong air.

[0149] S7: Stretching: Control the stretching rate to 0.7%.

[0150] S8: Aging: Develop a three-stage treatment of "pre-aging (120℃×8h) + regression (180℃×1h) + final aging (100℃×24h)", which results in discontinuous distribution of grain boundary precipitates and improved resistance to intergranular corrosion.

[0151] S9: Welding: Extruded profiles are welded using the "laser-MIG composite welding" process.

[0152] Remove the surface oxide film (Al2O3) with a stainless steel wire brush, then wipe clean with acetone or alcohol. Preheat the workpiece with a flame torch, keeping the preheating temperature between 80-100℃. Heating should be uniform to avoid localized overheating. During welding, the laser ignites a few milliseconds before the arc, forming a molten pool and keyhole on the workpiece surface (laser power 4.9kW, spot diameter 0.37mm, defocusing distance -2.0mm). The MIG arc then ignites immediately, attracting the plasma and metal vapor generated by the laser and quickly stabilizing near the laser's point of action. Use a dual-pulse MIG welding mode with a current range of 165-180A, a wire feed speed of 6.9m / min, and ER5356 / φ1.2mm welding wire. Laser and MIG hybrid welding was performed with the following parameters: laser filament spacing (DLA) of 2.7 mm, welding speed of 2.8 m / min, and a shielding gas of He (50%) + Ar (50%) with a gas flow rate of 25 L / min.

[0153] Reference Figure 1-3 The following is a detailed explanation based on the above embodiments 1-5 and comparative examples 1-3:

[0154] The mechanical properties and weld mechanical properties of the profiles prepared in Examples 1-5 and Comparative Examples 1-3 were tested. The test results are shown in Table 1.

[0155] Table 1 - Mechanical Properties of Aluminum-Zinc-Magnesium-Copper Alloy Profiles and Welds After Welding

[0156] Yield strength / MPa Tensile strength / MPa Post-weld tensile strength / MPa Welding joint coefficient Example 1 372 476 400 0.84 Example 2 379 480 408 0.85 Example 3 372 475 395 0.83 Example 4 374 481 385 0.80 Example 5 378 482 381 0.79 Comparative Example 1 380 485 364 0.75 Comparative Example 2 382 488 356 0.73 Comparative Example 3 386 489 342 0.70

[0157] Examples 1-5 have similar mechanical properties to Comparative Examples 1-3, with yield strength ≥360MPa and tensile strength ≥450MPa.

[0158] As the Cu content increases, the weld joint coefficient of the comparative examples 1-3 decreases slightly.

[0159] Adding vanadium (V) is beneficial to the mechanical properties of welded joints, and the welding performance of profiles with a V content of more than 0.1% is better than that of profiles with a V content of less than 0.1%.

[0160] As can be seen from Example 1 and Comparative Example 2, the "laser-MIG composite welding" process is superior to the traditional MIG welding process and can effectively improve the mechanical properties of the welded joint.

[0161] like Figure 3 As shown in Example 2, the strengthening phase of the extruded profile after aging treatment is uniformly dispersed, which effectively improves the strength and weldability of the alloy.

[0162] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0163] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0164] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0165] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0166] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A highly weldable and corrosion-resistant 7XXX aluminum alloy profile, characterized in that, By mass percentage, it includes: Si≤0.1%, Fe≤0.1%, Cu: 0.09~0.18%, Mn: 0.20~0.8%, Mg: 1.0~1.8%, Cr: 0.13~0.26%, Zn: 4.2~4.7%, Ti: 0.02~0.06%, Zr: 0.10~0.18%, V: 0.04~0.16%, Ce: 0.02~0.05%, with the remainder being Al and other unavoidable impurity elements.

2. The highly weldable and corrosion-resistant 7XXX aluminum alloy profile according to claim 1, characterized in that, The total content of the impurity elements is ≤0.10%, wherein the content of a single impurity element is ≤0.05%.

3. A method for preparing a highly weldable and corrosion-resistant 7XXX aluminum alloy profile according to any one of claims 1-2, characterized in that, Includes the following steps: S1, Ingredients High-purity aluminum ingots with a purity ≥99.85%, pure magnesium ingots with a purity ≥99.95%, and zinc ingots with a purity ≥99.995% are used. Si, Mn, Cr, Zr, Cu, and V are added in the form of corresponding aluminum-based master alloys. S2, Smelting Add the raw materials from step S1 into the melting furnace in the order of refractory metals or master alloys, heat to 720-760°C and stir electromagnetically until melted, degas and remove slag with sodium-free refining agent, and then adjust the temperature to 740-750°C; after preheating the Al-10%Ce master alloy ingot to 250-300°C, press it into the middle of the melt together with the pure magnesium ingot, and stir after melting; S3, degassing and filtration In step 2, high-purity Ar gas is used for rotary blowing to remove gas during the stirring process, with a rotor speed of 500-800 rpm; online three-stage filtration is used to control the size of inclusions to ≤5μm; S4, Casting After step 3 is completed, the casting is carried out at a temperature of 690-720℃ and uniformly cooled to obtain a round ingot with a diameter of ∅178-259mm; S5, Homogenization The circular ingot in step S4 is subjected to a cycle of holding at 470℃ → water cooling to room temperature → reheating to 470℃, repeated 3 times. S6, extrusion The homogenized ingot is preheated to 470±10℃ using electromagnetic induction heating, and the entire ingot is extruded. The extrusion outlet temperature of the profile is 478~488℃, and it is cooled after extrusion. S7, stretching The extruded profiles are then subjected to stretching treatment, with a stretching rate in the range of 0.5% to 1.5%. S8, Timeliness The profile after the stretching treatment in step S7 is subjected to a three-stage treatment: pre-aging at 120℃ for 8 hours, regression at 180℃ for 1 hour, and final aging at 100℃ for 24 hours. S9, Welding The profiles after aging treatment in step S8 are welded using a laser-MIG composite welding process, combined with pretreatment and specific welding parameters.

4. The method for preparing the high weldability and corrosion resistance 7XXX aluminum alloy profile according to claim 3, characterized in that, In step S2, the aluminum-based master alloy is at least one of Al-12%Si, Al-10%Mn, Al-5%Cr, Al-5%Zr, Al-50%Cu, and Al-10%V; the stirring method is mechanical stirring or electromagnetic stirring, and the stirring time is not less than 20 minutes.

5. The method for preparing the high weldability and corrosion resistance 7XXX aluminum alloy profile according to claim 3, characterized in that, In step S3, the high-purity Ar gas has a purity of ≥99.999%, and the bubbles formed by the spraying are small and evenly distributed.

6. The method for preparing the high weldability and corrosion resistance 7XXX aluminum alloy profile according to claim 3, characterized in that, In step S9, the pretreatment involves removing the surface oxide film with a stainless steel wire brush and then wiping it clean with acetone or alcohol; the weldment is then uniformly preheated to 70-100°C using a flame gun.

7. The method for preparing the high weldability and corrosion resistance 7XXX aluminum alloy profile according to claim 3, characterized in that, In step S9, the laser power is 3.5 to 4.5 kW, the spot diameter is 0.3 to 0.4 mm, and the defocusing amount is -2 to -4 mm.

8. The method for preparing the high weldability and corrosion resistance 7XXX aluminum alloy profile according to claim 7, characterized in that, In step S9, a dual-pulse MIG welding mode is used, with a current of 150-180A, a wire feed speed of 6.0-7.5m / min, and a welding wire size of ER5356 / φ1.2mm.

9. The method for preparing the high weldability and corrosion resistance 7XXX aluminum alloy profile according to claim 8, characterized in that, In step S9, the laser-MIG arc coordination parameters include a filament spacing of 1.5–2.5 mm and a welding speed of 1.8–2.5 m / min; a He(50%)+Ar(50%) shielding gas is used with a gas flow rate of 25–30 L / min.

10. The method for preparing the high weldability and corrosion resistance 7XXX aluminum alloy profile according to claim 9, characterized in that, In step S9, after welding, the material is slowly cooled to room temperature at a cooling rate of 20-30℃ / h.

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