High-strength 6110a aluminum alloy and preparation method and application thereof

Abstract

The application belongs to the technical field of aluminum alloy, and particularly relates to a high-strength 6110A aluminum alloy and a preparation method and application thereof. The aluminum alloy comprises the following components in percentage by mass: Si 0.84%-0.91%, Fe<=0.5%, Cu 0.3%-0.8%, Mn 0.3%-0.9%, Mg 1.0%-1.1%, Cr 0.05%-0.25%, Zn<=0.08%, Zr+Ti<=0.2%, the rest being Al and inevitable impurities, the single-element content of the impurities being <=0.03%, and the total content of the impurities being <=0.10%; wherein the mass ratio of Mg / Si is controlled in 1.1-1.3. The yield strength of the 6110A aluminum alloy is >=350MPa, the tensile strength is >=390MPa, the elongation rate is >=10%, and the bending angle is >=60 DEG, which is suitable for integrated extrusion forming of automobile load-bearing structural profiles, and the production yield is high.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy technology, specifically relating to a high-strength 6110A aluminum alloy, its preparation method, and its application. Background Technology

[0002] 6110A belongs to the 6000 series Al-Mg-Si wrought aluminum alloy, possessing formability, weldability, and anodizing properties. It is currently the mainstream material for lightweight structural components in fuel vehicles and new energy vehicles. Conventional commercial 6110A aluminum alloy focuses on processing and forming performance, with conservative alloy strengthening element ratios. Traditional manufacturing processes have the following shortcomings: 1. The matrix grains are coarse, which easily leads to central cracks and coarse surface grains during the casting stage. The extrusion molding of the profiles has a high cracking rate and the mechanical properties of the finished products are weak. The mechanical properties of conventionally prepared 6110A aluminum alloy cannot meet the high strength load-bearing requirements of new energy vehicle battery trays and load-bearing components.

[0003] 2. Traditional single-stage homogenization and single-stage aging processes result in uneven distribution and large size of the Mg2Si strengthening phase inside the alloy, leading to poor resistance to alternating fatigue and easy deformation cracking under long-term bumpy driving conditions.

[0004] Existing improved 6110A aluminum alloy processes mostly optimize single extrusion or aging parameters without systematically controlling the entire process of alloy composition, melting, homogenization, and heat treatment. This results in limited strength gains and a tendency to sacrifice material elongation, leading to poor matching of the overall mechanical properties of the profiles. Based on the integrated requirements of high strength, high toughness, fatigue resistance, and easy formability for automotive structural components, there is an urgent need to develop a high-strength 6110A aluminum alloy manufacturing process suitable for mass production and possessing excellent comprehensive performance. Summary of the Invention

[0005] To address the shortcomings of existing commercially available 6110A aluminum alloys, such as low strength, coarse grains, susceptibility to cracking during profile forming, and poor fatigue resistance, making them unsuitable for load-bearing structural components like chassis, anti-collision beams, and battery trays in new energy vehicles, this invention aims to provide a high-strength 6110A aluminum alloy, its preparation method, and its applications. This invention achieves a balance between strength and plasticity of the aluminum alloy through precise control of the Mg / Si atomic ratio, the use of composite trace refining elements, and optimization of the entire process, thereby improving fatigue resistance and corrosion resistance, making it suitable for mass extrusion production of automotive load-bearing structural components.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, embodiments of the present invention provide a high-strength 6110A aluminum alloy, comprising the following components by mass percentage: Si 0.84%-0.91%, Fe≤0.5%, Cu 0.3%-0.8%, Mn 0.3%-0.9%, Mg 1.0%-1.1%, Cr0.05%-0.25%, Zn≤0.08%, Zr+Ti≤0.2%, with the remainder being Al and unavoidable impurities, the content of a single impurity element ≤0.03%, and the total impurity content ≤0.10%; wherein the mass ratio of Mg / Si is controlled at 1.1-1.3.

[0007] This invention optimizes the Mg / Si ratio, controlling the Mg / Si mass ratio at 1.1-1.3 to maximize the precipitation of nanoscale Mg2Si strengthening phases; trace amounts of Zr and Ti work synergistically to form dispersed Al3Zr and Al3Ti particles, pinning grain boundaries, refining grains, and inhibiting high-temperature grain growth; low Fe content reduces the brittleness of the aluminum matrix and improves the elongation and fatigue resistance of the material; trace amounts of Cu and Cr optimize the precipitation sequence of strengthening phases and improve the aging strengthening efficiency of aluminum alloys.

[0008] Secondly, embodiments of the present invention provide a method for preparing a high-strength 6110A aluminum alloy, comprising the following steps: Step S1, graded smelting and slag formation: High-purity aluminum ingots are put into the smelting furnace and heated to 725-735℃ to be completely melted. The temperature is held for 15-20 minutes. Then, aluminum-silicon alloy, aluminum-copper alloy, aluminum-manganese alloy and aluminum-chromium alloy are evenly added into the smelting furnace. The temperature is raised to 740-745℃. Aluminum-magnesium alloy, aluminum-zirconium alloy and aluminum-titanium alloy are added to obtain primary smelted aluminum melt. Step S2, Deep purification of melt: Add composite refining slag remover to the primary aluminum melt in step S1, refine at a constant temperature for 12-18 minutes, mechanically remove surface slag; introduce high-purity argon gas for rotary degassing to obtain refined aluminum melt; Step S3, Semi-continuous casting: The refined aluminum melt is semi-continuously cast into aluminum alloy round casting rods. After the aluminum alloy round casting rods are removed from the production line, they are air-cooled to room temperature in sections. Step S4, Homogenization heat treatment: The aluminum alloy round casting rod is sent into a hot air homogenizing furnace and homogenized: the temperature is raised to 480-500℃ and held for 9-11 hours. Step S5, Low-temperature controlled-speed extrusion molding: The homogenized cast rod is subjected to low-speed constant-temperature extrusion. Step S6: The homogenized product from step S5 is straightened and cut to obtain an aluminum alloy finished product of the required size. The aluminum alloy finished product is then subjected to a two-stage aging treatment to obtain a 6110A aluminum alloy finished product.

[0009] Further, in step S2, the amount of the composite refining slag remover is 0.25-0.35% of the total mass of the aluminum melt, and the hydrogen content of the refined aluminum melt is ≤0.12mL / 100gAl.

[0010] Furthermore, in step S3, when the refined aluminum melt is semi-continuously cast, the temperature of the circulating cooling water is controlled at 28-32℃, the water pressure at 0.18-0.22MPa, and the casting speed at 54-62mm / min.

[0011] Further, in step S5, during extrusion molding, the homogenized casting rod is preheated to 520-530℃, the extrusion die is preheated to 470-490℃, the extrusion cylinder is preheated to 430-440℃, the extrusion speed is 1.2-1.8mm / s, and the extrusion ratio is 30-32:1.

[0012] Furthermore, in step S6, the first-stage low-temperature aging is carried out at 80-100℃ for 4 hours to precipitate fine primary strengthening phases; the second-stage medium-temperature aging is carried out at 170-180℃ for 6 hours to regulate the size and distribution of the strengthening phases and prevent them from agglomerating and growing. After aging is completed, the temperature is cooled to room temperature.

[0013] Thirdly, embodiments of the present invention provide a high-strength 6110A aluminum alloy, which is prepared by the preparation method described in the second aspect. The aluminum alloy satisfies the following conditions: yield strength ≥350MPa, tensile strength ≥390MPa, elongation ≥10%, and bending angle ≥60°.

[0014] Fourthly, embodiments of the present invention provide an application of a high-strength 6110A aluminum alloy, which is used in automobile manufacturing.

[0015] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows: 1. Precise modification of composition, significantly improved mechanical properties: This invention optimizes the alloy element ratio, fine-tunes the ratio of Mg and Si strengthening phases, and adds trace amounts of Zr and Ti grain-refining elements. Combined with low-temperature controlled-speed extrusion and gradient solution aging integrated process, it refines the aluminum alloy matrix grains, eliminates coarse grain layer and central crack defects in the cast ingot, and optimizes the precipitation morphology of Mg2Si strengthening phase. This results in an aluminum alloy with a yield strength ≥350MPa, tensile strength ≥390MPa, elongation ≥10%, and bending angle ≥60°. Compared with the traditional 6110A aluminum alloy, the yield strength is improved, balancing high strength and high toughness, and is suitable for the load-bearing requirements of automotive load-bearing structures.

[0016] 2. Full-process process control of defects and high production yield: graded melting reduces magnesium element burn-off, electromagnetic assisted casting eliminates casting rod cracks, low-temperature extrusion reduces profile cracking rate, and is suitable for large-scale mass production of automotive profiles.

[0017] 3. Heat treatment process adapted to automotive conditions: dual-stage aging control enhances phase morphology, improves the fatigue performance of materials under alternating loads, and is suitable for long-term use in complex outdoor road conditions of automobiles.

[0018] 4. Strong process compatibility: No need to modify existing smelting, extrusion, and heat treatment production lines; process parameters are controllable; energy consumption increment is low; it can be directly connected to existing automotive aluminum alloy profile production lines for implementation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the cross-sectional structure of the extruded product prepared using 6110A casting rod in Example 1.

[0020] Figure 2 The image shows the metallographic structure of the 6110A aluminum alloy cast rod at 200 μm in Example 1.

[0021] Figure 3 The image shows the metallographic structure of the 6110A aluminum alloy cast rod at 50 μm in Example 1.

[0022] Figure 4 The image shows the metallographic structure of the 6110A aluminum alloy finished product at 200μm in Example 1.

[0023] Figure 5 The image shows the metallographic structure of the 6110A aluminum alloy finished product at 50μm in Example 1. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 A high-strength 6110A aluminum alloy, by mass fraction, comprises the following components: Si: 0.84%, Fe: 0.25%, Cu: 0.5%, Mn: 0.6%, Mg: 1.1%, Cr: 0.15%, Zn: 0.03%, Zr+Ti: 0.1%, with the balance being Al and unavoidable impurities, wherein the content of a single impurity element is ≤0.03%, the total impurity content is ≤0.10%, and the Mg / Si mass ratio is controlled at 1.3.

[0026] The preparation method of the above-mentioned high-strength 6110A aluminum alloy includes the following steps: Step S1, Raw material selection: High-purity aluminum ingots with a purity of 99.85% and intermediate alloys AlSi20, AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 are selected as raw materials. Among them, AlSi20 is an aluminum-silicon alloy, indicating that the mass fraction of silicon in the alloy is 20% and the mass fraction of aluminum is 80%. The representation methods of AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 are the same as those of AlSi20. Step S2, Staged Melting and Slag Formation: High-purity aluminum ingots are added to a gas-fired melting furnace and heated to 730℃ for complete melting. The furnace is held at this temperature for 15 minutes. Intermediate alloys AlSi20, AlCu5, AlMn10, and AlCr10 are then uniformly added to the furnace. The temperature is raised to 745℃, and then intermediate alloys AlMg20, AlZr5, and AlTi5 are added to the furnace to obtain primary aluminum melt. Staged feeding avoids the loss of easily oxidized Mg elements, and the nine-grid feeding ensures uniform distribution of alloy elements throughout the entire process, preventing localized component segregation. Step S3, Deep purification of melt: Add composite refining slag remover to the primary aluminum melt, the amount of which is 0.30% of the total mass of the aluminum melt, refine at a constant temperature for 15 minutes, and mechanically remove the surface slag; introduce high-purity argon gas for rotary degassing to obtain refined aluminum melt, the hydrogen content of which is 0.05mL / 100gAl; Step S4, Semi-continuous casting: Control the temperature of the circulating cooling water to 30℃, the casting speed to 58mm / min, and the cooling water pressure to 0.20MPa. Semi-continuously cast the refined aluminum melt into Φ254mm aluminum alloy round casting rods. After the casting rods are removed from the production line, they are air-cooled to room temperature in sections to completely avoid defects such as central cracks and shrinkage cavities in the casting rods. Step S5, Homogenization treatment: The aluminum alloy casting rod obtained in step S4 is sent into a hot air homogenizing furnace and a homogenization process is performed: the temperature is raised to 490℃ and held for 10 hours. After homogenization treatment, the rod is taken out of the furnace and water-cooled to room temperature to relieve the casting stress and achieve solid solution homogenization of alloy elements. Step S6, Low-Temperature Speed-Controlled Extrusion Molding: The homogenized casting rod is preheated to 525℃; the extrusion die is preheated to 480℃; the extrusion cylinder is heated to 435℃; the preheated casting rod is extruded using a 3600MN forward extruder, with the extrusion speed controlled at 1.5mm / s, the extrusion ratio at 31:1, the discharge speed at 2.7m / min, and the casting rod diameter at 256mm. Step S7, Straightening: The product obtained in step S6 is straightened with a stretching rate of 1.5%; Step S8, Cutting: Cut the product obtained in step S7 into finished products of a fixed length, thus obtaining the finished product.

[0027] Step S9, Two-stage aging heat treatment: The finished product obtained in step S8 is subjected to aging treatment. The aging treatment process is a two-stage aging process. The first stage aging process is at 80℃ for 4 hours, and the second stage aging process is at 175℃ for 6 hours, thus obtaining the high-strength 6110A aluminum alloy finished product.

[0028] Example 2 A high-strength 6110A aluminum alloy, by mass fraction, comprises the following components: Si: 0.91%, Fe: 0.25%, Cu: 0.5%, Mn: 0.6%, Mg: 1.1%, Cr: 0.15%, Zn: 0.03%, Zr+Ti: 0.1%, with the balance being Al and unavoidable impurities, wherein the content of a single impurity element is ≤0.03%, the total impurity content is ≤0.10%, and the Mg / Si mass ratio is controlled at 1.2.

[0029] The preparation method of the above-mentioned high-strength 6110A aluminum alloy includes the following steps: Step S1, Raw material selection: High-purity aluminum ingots with a purity of 99.85%, AlSi20, AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 master alloys are selected as raw materials. Among them, AlSi20 is an aluminum-silicon alloy, indicating that the mass fraction of silicon in the alloy is 20% and the mass fraction of aluminum is 80%. The representation methods of AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 are the same as those of AlSi20. Step S2, Staged Melting and Slag Formation: High-purity aluminum ingots are added to a gas-fired melting furnace and heated to 730℃ for complete melting. The furnace is held at this temperature for 15 minutes. Intermediate alloys AlSi20, AlCu5, AlMn10, and AlCr10 are then uniformly added to the furnace. The temperature is raised to 745℃, and then intermediate alloys AlMg20, AlZr5, and AlTi5 are added to the furnace to obtain primary aluminum melt. Staged feeding avoids the loss of easily oxidized Mg elements, and the nine-grid feeding ensures uniform distribution of alloy elements throughout the entire process, preventing localized component segregation. Step S3, Deep purification of melt: Add composite refining slag remover to the primary aluminum melt, the amount of which is 0.30% of the total mass of the aluminum melt, refine at a constant temperature for 15 minutes, mechanically remove the surface slag, and introduce high-purity argon gas for rotary degassing to obtain refined aluminum melt. The hydrogen content of the refined aluminum melt is 0.05 mL / 100gAl. Step S4, Semi-continuous casting: Control the temperature of the circulating cooling water to 30℃, the casting speed to 58mm / min, and the cooling water pressure to 0.20MPa. Semi-continuously cast the refined aluminum melt into Φ254mm aluminum alloy round casting rods. After the casting rods are removed from the production line, they are cooled to room temperature in sections to completely avoid defects such as central cracks and shrinkage cavities in the casting rods. Step S5, Homogenization treatment: The aluminum alloy casting rod obtained in step S4 is sent into a hot air homogenizing furnace and a homogenization process is performed: the temperature is raised to 490℃ and held for 10 hours. After homogenization treatment, the rod is taken out of the furnace and water-cooled to room temperature to relieve the casting stress and achieve solid solution homogenization of alloy elements. Step S6, Low-temperature controlled-speed extrusion molding: The cast rod obtained in step S5 is preheated to 525℃; the extrusion die is preheated to 480℃; the die cylinder is heated to 435℃; the preheated cast rod is extruded using a 3600MN forward extruder, with the extrusion speed controlled at 1.5mm / s, the extrusion ratio at 31:1, the discharge speed at 2.7m / min, and the cast rod diameter at 256mm. Step S7, Straightening: The product obtained in step S6 is straightened with a stretching rate of 1.5%; Step S8, Cutting: Cut the product obtained in step S7 into finished products of fixed lengths to obtain the finished products; Step S9, Two-stage aging heat treatment: The finished product obtained in step S8 is subjected to aging treatment. The aging treatment process is a two-stage aging process. The first stage aging process is at 80℃ for 4 hours, and the second stage aging process is at 175℃ for 6 hours, thus obtaining the high-strength 6110A aluminum alloy finished product.

[0030] Example 3 A high-strength 6110A aluminum alloy, by mass fraction, comprises the following components: Si: 0.91%, Fe: 0.25%, Cu: 0.5%, Mn: 0.6%, Mg: 1.0%, Cr: 0.15%, Zn: 0.03%, Zr+Ti: 0.1%, with the balance being Al and unavoidable impurities, wherein the content of a single impurity element is ≤0.03%, the total impurity content is ≤0.10%, and the Mg / Si mass ratio is controlled at 1.1.

[0031] The preparation method of the above-mentioned high-strength 6110A aluminum alloy includes the following steps: Step S1, Raw material selection: High-purity aluminum ingots with a purity of 99.85%, AlSi20, AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 master alloys are selected as raw materials. Among them, AlSi20 is an aluminum-silicon alloy, indicating that the mass fraction of silicon in the alloy is 20% and the mass fraction of aluminum is 80%. The representation methods of AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 are the same as those of AlSi20. Step S2, Staged Melting and Slag Formation: High-purity aluminum ingots are added to a gas-fired melting furnace and heated to 730℃ for complete melting. The furnace is held at this temperature for 15 minutes. Intermediate alloys AlSi20, AlCu5, AlMn10, and AlCr10 are then uniformly added to the furnace. The temperature is raised to 745℃, and then intermediate alloys AlMg20, AlZr5, and AlTi5 are added to the furnace to obtain primary aluminum melt. Staged feeding avoids the loss of easily oxidized Mg elements, and the nine-grid feeding ensures uniform distribution of alloy elements throughout the entire process, preventing localized component segregation. Step S3, Deep purification of melt: Add composite refining slag remover to the primary aluminum melt, the amount of which is 0.30% of the total mass of the aluminum melt, refine at a constant temperature for 15 minutes, and mechanically remove the surface slag; introduce high-purity argon gas for rotary degassing to obtain refined aluminum melt, the hydrogen content of which is 0.05mL / 100gAl; Step S4, Semi-continuous casting: Control the temperature of the circulating cooling water to 30℃, the casting speed to 58mm / min, and the cooling water pressure to 0.20MPa. Semi-continuously cast the refined aluminum melt into Φ254mm aluminum alloy round casting rods. After the casting rods are removed from the production line, they are cooled to room temperature in sections to completely avoid defects such as central cracks and shrinkage cavities in the casting rods. Step S5, Homogenization treatment: The aluminum alloy casting rod obtained in step S4 is sent into a hot air homogenizing furnace and a homogenization process is performed: the temperature is raised to 490℃ and held for 10 hours. After homogenization treatment, the rod is taken out of the furnace and water-cooled to room temperature to relieve the casting stress and achieve solid solution homogenization of alloy elements. Step S6, Low-temperature speed-controlled extrusion molding: The cast rod obtained in step S5 is heated to 525°C for preheating; the extrusion die is heated and preheated to 480°C; the die cylinder is heated to 435°C. The preheated cast rod was extruded using a 3600MN forward extrusion press. The extrusion speed was controlled at 1.5 mm / s, the extrusion ratio at 31:1, the discharge speed at 2.7 m / min, and the cast rod diameter at 256 mm. Step S7, Straightening: The product obtained in step S6 is straightened with a stretching rate of 1.5%; Step S8, Cutting: Cut the product obtained in step S7 into finished products of fixed lengths to obtain the finished products; Step S9, Two-stage aging heat treatment: The finished product obtained in step S8 is subjected to aging treatment. The aging treatment process is a two-stage aging process. The first stage aging process is at 100℃ for 4 hours, and the second stage aging process is at 175℃ for 6 hours, thus obtaining the high-strength 6110A aluminum alloy finished product.

[0032] Example 4 A high-strength 6110A aluminum alloy, by mass fraction, comprises the following components: Si: 0.84%, Fe: 0.25%, Cu: 0.5%, Mn: 0.6%, Mg: 1.0%, Cr: 0.15%, Zn: 0.03%, Zr+Ti: 0.1%, with the balance being Al and unavoidable impurities, wherein the content of a single impurity element is ≤0.03%, the total impurity content is ≤0.10%, and the Mg / Si mass ratio is controlled at 1.2.

[0033] The preparation method of the above-mentioned high-strength 6110A aluminum alloy includes the following steps: Step S1, Raw material selection: High-purity aluminum ingots with a purity of 99.85% and intermediate alloys AlSi20, AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 are selected as raw materials. Among them, AlSi20 is an aluminum-silicon alloy, indicating that the mass fraction of silicon in the alloy is 20% and the mass fraction of aluminum is 80%. The representation methods of AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 are the same as those of AlSi20. Step S2, Staged Melting and Slag Formation: High-purity aluminum ingots are added to a gas-fired melting furnace and heated to 730℃ for complete melting. The furnace is held at this temperature for 15 minutes. Intermediate alloys AlSi20, AlCu5, AlMn10, and AlCr10 are then uniformly added to the furnace. The temperature is raised to 745℃, and then intermediate alloys AlMg20, AlZr5, and AlTi5 are added to the furnace to obtain primary aluminum melt. Staged feeding avoids the loss of easily oxidized Mg elements, and the nine-grid feeding ensures uniform distribution of alloy elements throughout the entire process, preventing localized component segregation. Step S3, Deep purification of melt: Add composite refining slag remover to the primary aluminum melt, the amount of which is 0.30% of the total mass of the aluminum melt, refine at a constant temperature for 15 minutes, and mechanically remove the surface slag; introduce high-purity argon gas for rotary degassing to obtain refined aluminum melt, the hydrogen content of which is 0.05mL / 100gAl; Step S4, Semi-continuous casting: Control the temperature of the circulating cooling water to 30℃, the casting speed to 58mm / min, and the cooling water pressure to 0.20MPa. Semi-continuously cast the refined aluminum melt into Φ254mm aluminum alloy round casting rods. After the casting rods are removed from the production line, they are cooled to room temperature in sections to completely avoid defects such as central cracks and shrinkage cavities in the casting rods. Step S5, Homogenization treatment: The aluminum alloy casting rod obtained in step S4 is sent into a hot air homogenizing furnace and a homogenization process is performed: the temperature is raised to 490℃ and held for 10 hours. After homogenization treatment, the rod is taken out of the furnace and water-cooled to room temperature to relieve the casting stress and achieve solid solution homogenization of alloy elements. Step S6, Low-temperature controlled-speed extrusion molding: The cast rod obtained in step S5 is preheated to 525℃; the extrusion die is heated to 480℃; the die cylinder is heated to 435℃; the preheated cast rod is extruded using a 3600MN forward extruder, with the extrusion speed controlled at 1.5mm / s, the extrusion ratio at 31:1, the discharge speed at 2.7m / min, and the cast rod diameter at 256mm. Step S7, Straightening: The product obtained in step S6 is straightened with a stretching rate of 1.5%; Step S8, Cutting: Cut the product obtained in step S7 into finished products of a fixed length, thus obtaining the finished product.

[0034] Step S9, Two-stage aging heat treatment: The finished product obtained in step S8 is subjected to aging treatment. The aging treatment process is a two-stage aging process. The first stage aging process is at 100℃ for 4 hours, and the second stage aging process is at 175℃ for 6 hours.

[0035] After various inspections of the 6110A cast rods and extruded finished products, the mechanical properties of the 6110A complex structural parts produced using this manufacturing method meet the product requirements.

[0036] Comparative Example 1 A high-strength 6110A aluminum alloy, by mass fraction, comprises the following components: Si: 0.8%, Fe: 0.25%, Cu: 0.5%, Mn: 0.6%, Mg: 1.15%, Cr: 0.15%, Zn: 0.03%, Zr+Ti: 0.1%, with the balance being Al and unavoidable impurities, wherein the content of a single impurity element is ≤0.03%, the total impurity content is ≤0.10%, and the Mg / Si mass ratio is controlled at 1.4.

[0037] The preparation method of the above-mentioned high-strength 6110A aluminum alloy includes the following steps: Step S1, Raw material selection: 99.85% high-purity aluminum ingots, AlSi20, AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 master alloys are selected as raw materials. Among them, AlSi20 is an aluminum-silicon alloy, indicating that the mass fraction of silicon in the alloy is 20% and the mass fraction of aluminum is 80%. The representation methods of AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 are the same as those of AlSi20. Step S2, Staged Melting and Slag Formation: High-purity aluminum ingots are added to a gas-fired melting furnace and heated to 730°C until completely melted. The furnace is held at this temperature for 15 minutes. Intermediate alloys AlSi20, AlCu5, AlMn10, and AlCr10 are then uniformly added to the furnace. The temperature is raised to 745°C, and then intermediate alloys AlMg20, AlCr10, and AlTi5 are added to the furnace to obtain primary aluminum melt. Staged feeding avoids the loss of easily oxidized Mg elements, and the nine-grid feeding ensures uniform distribution of alloy elements throughout the entire process, preventing localized component segregation. Step S3, Deep purification of melt: Add composite refining slag remover to the primary aluminum melt, the amount of which is 0.30% of the total mass of the aluminum melt, refine at a constant temperature for 15 minutes, and mechanically remove the surface slag; introduce high-purity argon gas for rotary degassing to obtain refined aluminum melt, the hydrogen content of which is 0.05mL / 100gAl; Step S4, Semi-continuous casting: Control the temperature of the circulating cooling water to 30℃, the casting speed to 58mm / min, and the cooling water pressure to 0.20MPa. Semi-continuously cast the refined aluminum melt into Φ254mm aluminum alloy round casting rods. After the casting rods are removed from the production line, they are cooled to room temperature in sections to completely avoid defects such as central cracks and shrinkage cavities in the casting rods.

[0038] Step S5, Homogenization treatment: The aluminum alloy casting rod obtained in step S4 is sent into a hot air homogenizing furnace and a homogenization process is performed: the temperature is raised to 490℃ and held for 10 hours. After homogenization treatment, the rod is taken out of the furnace and water-cooled to room temperature to relieve the casting stress and achieve solid solution homogenization of alloy elements. Step S6, Low-temperature speed-controlled extrusion molding: The cast rod obtained in step S5 is preheated to 525°C; the extrusion die is heated to 480°C; the die cylinder is heated to 435°C. The preheated cast rod was extruded using a 3600MN forward extrusion press. The extrusion speed was controlled at 1.5 mm / s, the extrusion ratio at 31:1, the discharge speed at 2.7 m / min, and the cast rod diameter at 256 mm. Step S7, Straightening: The product obtained in step S6 is straightened with a stretching rate of 1.5%; Step S8, Cutting: Cut the product obtained in step S7 into finished products of fixed lengths to obtain the finished products; Step S9, Two-stage aging heat treatment: The finished product obtained in step S8 is subjected to aging treatment. The aging treatment process is a two-stage aging process. The first stage aging process is at 80℃ for 4 hours, and the second stage aging process is at 175℃ for 6 hours.

[0039] After various inspections of the 6110A cast rods and extruded finished products, the mechanical properties or bending angles of the 6110A complex structural parts produced using Comparative Example 1 did not meet the product requirements.

[0040] Comparative Example 2 A high-strength 6110A aluminum alloy, by mass fraction, comprises the following components: Si: 1.0%, Fe: 0.25%, Cu: 0.5%, Mn: 0.6%, Mg: 1.0%, Cr: 0.15%, Zn: 0.03%, Zr+Ti: 0.1%, with the balance being Al and unavoidable impurities, wherein the content of a single impurity element is ≤0.03%, the total impurity content is ≤0.10%, and the Mg / Si mass ratio is controlled at 1.

[0041] The preparation method of the above-mentioned high-strength 6110A aluminum alloy includes the following steps: Step S1, Raw material selection: High-purity aluminum ingots with a purity of 99.85% and intermediate alloys AlSi20, AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 are selected as raw materials. Among them, AlSi20 is an aluminum-silicon alloy, indicating that the mass fraction of silicon in the alloy is 20% and the mass fraction of aluminum is 80%. The representation methods of AlMg20, AlCu5, AlMn10, AlCr10, AlZr5, and AlTi5 are the same as those of AlSi20. Step S2, Staged Melting and Slag Formation: High-purity aluminum ingots are added to a gas-fired melting furnace and heated to 730°C until completely melted. The furnace is held at this temperature for 15 minutes. Intermediate alloys AlSi20, AlCu5, AlMn10, and AlCr10 are then uniformly added to the furnace. The temperature is raised to 745°C, and then intermediate alloys AlMg20, AlZr5, and AlTi5 are added to the furnace to obtain primary aluminum melt. Staged feeding avoids the loss of easily oxidized Mg elements, and the nine-grid feeding ensures uniform distribution of alloy elements throughout the entire process, preventing localized component segregation.

[0042] Step S3, Deep purification of melt: Add composite refining slag remover to the primary aluminum melt, the amount of which is 0.30% of the total mass of the aluminum melt, refine at a constant temperature for 15 minutes, and mechanically remove the surface slag; introduce high-purity argon gas for rotary degassing to obtain refined aluminum melt, the hydrogen content of which is 0.05mL / 100gAl; Step S4, Semi-continuous casting: Control the temperature of the circulating cooling water to 30℃, the casting speed to 58mm / min, and the cooling water pressure to 0.20MPa. Semi-continuously cast the refined aluminum melt into Φ254mm aluminum alloy round casting rods. After the casting rods are removed from the production line, they are cooled to room temperature in sections to completely avoid defects such as central cracks and shrinkage cavities in the casting rods.

[0043] Step S5, Homogenization treatment: The aluminum alloy casting rod obtained in step S4 is sent into a hot air homogenizing furnace and a homogenization process is performed: the temperature is raised to 490℃ and held for 10 hours. After homogenization treatment, the rod is taken out of the furnace and water-cooled to room temperature to relieve the casting stress and achieve solid solution homogenization of alloy elements. Step S6, Low-temperature controlled-speed extrusion molding: The homogenized casting rod is preheated to 525°C; the extrusion die is heated to 480°C; the die cylinder is heated to 435°C. The preheated cast rod was extruded using a 3600MN forward extrusion press. The extrusion speed was controlled at 1.5 mm / s, the extrusion ratio at 31:1, the discharge speed at 2.7 m / min, and the cast rod diameter at 256 mm. Step S7, Straightening: The product obtained in step S6 is straightened with a stretching rate of 1.5%; Step S8, Cutting: Cut the product obtained in step S7 into finished products of a fixed length, thus obtaining the finished product.

[0044] Step S9, Two-stage aging heat treatment: The finished product obtained in step S8 is subjected to aging treatment. The aging treatment process is a two-stage aging process. The first stage of aging is held at 80℃ for 4 hours, and the second stage of aging is held at 175℃ for 6 hours.

[0045] After various inspections of the 6110A cast rods and extruded finished products, the mechanical properties or bending angles of the 6110A complex structural parts produced using Comparative Example 2 did not meet the product requirements.

[0046] The mechanical properties of the aluminum alloy products obtained in Examples 1-4 and Comparative Examples 1-2 are shown in Table 1 below. It can be seen that the finished products of Examples 1-4 can meet the product usage requirements, while the finished products of Comparative Examples 1-2 cannot meet the product usage requirements.

[0047] Table 1. Performance parameters of complex aluminum alloy structural components made of 6110A aluminum alloy in Examples 1-4 and Comparative Examples 1-2. The cross-section of the extruded product prepared using 6110A casting rod in Example 1 is as follows: Figure 1 .

[0048] Metallographic examination of the 6110A casting rod in Example 1 is as follows: Figure 2 , Figure 3 The study provides metallographic images of the grains at two field-of-view scales. The grain size of the cast rod within the field of view is ≤50μm, and the grain size is uniform with no obvious overheated structure.

[0049] Metallographic examination of the final aluminum alloy product obtained in Example 1 is shown in the figure. Figure 4 , Figure 5The study provides metallographic images of the grains at two field-of-view scales. The grain size within each field of view is ≤15μm, exhibiting equiaxed, fine grains with no obvious coarse grains or localized abnormal grain growth. The grain size variation is minimal, and the grain distribution is uniform and dense, without mixed grains, banded grains, or coarse grain aggregation defects. Grain boundaries are continuous, intact, and uniformly distributed. During stamping, forging, and bending, deformation is uniform, reducing the likelihood of localized cracking, orange peel texture, or uneven thickness. The microstructure transformation is synchronized during heat treatment, resulting in minimal performance fluctuations after quenching and aging, and high product consistency. This provides advantages such as high strength and high toughness for subsequent product processing.

[0050] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-strength 6110A aluminum alloy, characterized in that, By mass percentage, it includes the following components: Si 0.84%-0.91%, Fe≤0.5%, Cu 0.3%-0.8%, Mn 0.3%-0.9%, Mg 1.0%-1.1%, Cr 0.05%-0.25%, Zn≤0.08%, Zr+Ti≤0.2%, with the remainder being Al and unavoidable impurities. The content of a single impurity element is ≤0.03%, and the total impurity content is ≤0.10%. The mass ratio of Mg / Si is controlled between 1.1 and 1.

3.

2. A method for preparing a high-strength 6110A aluminum alloy, characterized in that, Includes the following steps: Step S1, graded smelting and slag formation: High-purity aluminum ingots are put into the smelting furnace and heated to 725-735℃ to be completely melted. The temperature is held for 15-20 minutes. Then, aluminum-silicon alloy, aluminum-copper alloy, aluminum-manganese alloy and aluminum-chromium alloy are evenly added into the smelting furnace. The temperature is raised to 740-745℃. Aluminum-magnesium alloy, aluminum-zirconium alloy and aluminum-titanium alloy are added to obtain primary smelted aluminum melt. Step S2, Deep purification of melt: Add composite refining slag remover to the primary aluminum melt in step S1, refine at a constant temperature for 12-18 minutes, mechanically remove surface slag; introduce high-purity argon gas for rotary degassing to obtain refined aluminum melt; Step S3, Semi-continuous casting: The refined aluminum melt is semi-continuously cast into aluminum alloy round casting rods. After the aluminum alloy round casting rods are removed from the production line, they are air-cooled to room temperature in sections. Step S4, Homogenization heat treatment: The aluminum alloy round casting rod is sent into a hot air homogenizing furnace and homogenized: the temperature is raised to 480-500℃ and held for 9-11 hours. Step S5, Low-temperature controlled-speed extrusion molding: The homogenized cast rod is subjected to low-speed constant-temperature extrusion. Step S6: The homogenized product from step S5 is straightened and cut to obtain an aluminum alloy finished product of the required size. The aluminum alloy finished product is then subjected to a two-stage aging treatment to obtain a 6110A aluminum alloy finished product.

3. The method for preparing high-strength 6110A aluminum alloy according to claim 2, characterized in that, In step S2, the amount of the composite refining slag remover is 0.25-0.35% of the total mass of the aluminum melt, and the hydrogen content of the refined aluminum melt is ≤0.12mL / 100gAl.

4. The method for preparing high-strength 6110A aluminum alloy according to claim 2, characterized in that, In step S3, when the refined aluminum melt is semi-continuously cast, the temperature of the circulating cooling water is controlled at 28-32℃, the water pressure at 0.18-0.22MPa, and the casting speed at 54-62mm / min.

5. The method for preparing high-strength 6110A aluminum alloy according to claim 2, characterized in that, In step S5, during extrusion molding, the homogenized casting rod is preheated to 520-530℃, the extrusion die is preheated to 470-490℃, the extrusion cylinder is preheated to 430-440℃, the extrusion speed is 1.2-1.8mm / s, and the extrusion ratio is 30-32:

1.

6. The method for preparing high-strength 6110A aluminum alloy according to claim 2, characterized in that, In step S6, the first-stage low-temperature aging is carried out at 80-100℃ for 4 hours; the second-stage medium-temperature aging is carried out at 170-180℃ for 6 hours, and then cooled to room temperature after aging is completed.

7. A high-strength 6110A aluminum alloy, characterized in that, The aluminum alloy is prepared by any one of claims 2-6 and meets the following conditions: yield strength ≥ 350 MPa, tensile strength ≥ 390 MPa, elongation ≥ 10%, and bending angle ≥ 60°.

8. An application of a high-strength 6110A aluminum alloy, characterized in that, The 6110A aluminum alloy is used in automobile manufacturing.

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