A high-strength 6-series aluminum alloy for automobile anti-collision beams and its preparation method

Abstract

The present invention discloses a high-strength 6-series aluminum alloy for automobile anti-collision beams. The alloy is composed of the following chemical components, based on the total mass of the aluminum alloy: Si: 0.80-1.20%, Mg: 0.70-1.15%, Cu: 0.15-0.80%, Mn: 0.10-0.50%, Cr: 0.05-0.20%, Ti: ≤0.1%, V: ≤0.15%, Fe: ≤0.18%, and the balance is Al and unavoidable impurity elements; the content of the impurity elements is ≤0.15%; wherein, 0.8≤Mg / Si≤1.2, -0.2≤Si-1.33Mg≤0, -0.4≤Mg-1.02Si-0.3Cu≤-0.2, and 1.5≤Ti / V≤2.5. The aluminum alloy prepared by the chemical composition provided by the present invention has excellent aging state, tensile strength, yield strength, elongation, and tensile strength reduction after 30 days.

Description

Technical Field

[0001] The present invention relates to the field of aluminum alloys, and in particular to a high-strength 6 series aluminum alloy for automobile anti-collision beams and a preparation method thereof. Background Art

[0002] As the most abundant metallic element on Earth, aluminum alloys are widely used in lightweight transportation due to their low density and recyclability. Cast aluminum alloys are primarily used in components such as wheels and engines; 2-series aluminum alloys are primarily used in automotive body panels; and 6-series aluminum alloys are primarily used in body panels and frame materials. Crash boxes and impact beams are key components of automotive passive safety systems. During a collision, they primarily absorb energy through deformation or transfer it to the vehicle body, thereby protecting the occupants. Generally, crash boxes are made of 6-series aluminum alloys, such as 6063 and 6008, while impact beams are made of 7-series aluminum alloys, such as 7003 and 7005, which offer higher strength. Crash boxes and impact beams are typically connected through welding and bolts. 7-series aluminum alloys have poor weldability, necessitating separate recycling of 6-series and 7-series aluminum alloys during the recycling of impact beam systems. However, existing 6-series aluminum alloys suffer from poor aging performance, including tensile strength, yield strength, elongation, and a decrease in tensile strength after 30 days.

[0003] In summary, after extensive searches by the applicant, it has been found that at least the existing 6-series aluminum alloys in this field have problems with their aging state, tensile strength, yield strength, elongation, and the decrease in tensile strength after 30 days. Therefore, it is necessary to develop or improve a high-strength 6-series aluminum alloy for automobile anti-collision beams and a preparation method thereof. Summary of the Invention

[0004] Based on this, in order to solve the problem that the existing 6 series aluminum alloys have poor performance in aging state, tensile strength, yield strength, elongation, and tensile strength drop after 30 days, the present invention provides a high-strength 6 series aluminum alloy for automobile anti-collision beams and a preparation method thereof. The specific technical solution is as follows:

[0005] A high-strength 6 series aluminum alloy for automobile anti-collision beams, based on the total mass of the aluminum alloy, is composed of the following chemical components:

[0006] Si: 0.80-1.20%, Mg: 0.70-1.15%, Cu: 0.15-0.80%, Mn: 0.10-0.50%, Cr: 0.05-0.20%, Ti: ≤0.1%, V: ≤0.15%, Fe: ≤0.18%, the balance being Al and unavoidable impurity elements;

[0007] The content of the impurity element is ≤0.15%;

[0008] Among them, 0.8≤Mg / Si≤1.2, -0.2≤Si-1.33Mg≤0, -0.4≤Mg-1.02Si-0.3Cu≤-0.2, 1.5≤Ti / V≤2.5.

[0009] This technical solution also provides a method for preparing a high-strength 6-series aluminum alloy for automobile anti-collision beams, which comprises the following steps:

[0010] The raw materials are prepared according to the chemical composition, then added into the melting furnace for melting, the melt is refined, degassed and filtered, and then the liquid aluminum alloy is cast into aluminum alloy rods;

[0011] placing the aluminum alloy cast rod in a homogenizing furnace for homogenization treatment to obtain a homogenized aluminum alloy cast rod;

[0012] Cooling the homogenized aluminum alloy cast rod to obtain a cooled aluminum alloy cast rod;

[0013] Extruding the cooled aluminum alloy cast rod to obtain an aluminum alloy profile;

[0014] quenching the aluminum alloy profile to obtain a quenched aluminum alloy;

[0015] Performing aging treatment on the quenched aluminum alloy to obtain the high-strength 6 series aluminum alloy for automobile anti-collision beams;

[0016] The chemical composition is as follows: based on the total mass of the aluminum alloy, Si: 0.80-1.20%, Mg: 0.70-1.15%, Cu: 0.15-0.80%, Mn: 0.10-0.50%, Cr: 0.05-0.20%, Ti: ≤0.1%, V: ≤0.15%, Fe: ≤0.18%, and the balance is Al and unavoidable impurity elements;

[0017] The content of the impurity elements is ≤0.15%; among which, 0.8≤Mg / Si≤1.2, -0.2≤Si-1.33Mg≤0, -0.4≤Mg-1.02Si-0.3Cu≤-0.2, and 1.5≤Ti / V≤2.5.

[0018] Furthermore, the refining is performed twice.

[0019] Furthermore, the gas used for degassing is high-purity argon.

[0020] Furthermore, the filtration adopts double-stage filtration.

[0021] Furthermore, the homogenization process comprises the following steps:

[0022] The aluminum alloy cast rod is placed in a homogenizing furnace, the temperature is set at 500-560° C., and the temperature is kept at 8-16 hours to obtain the homogenized aluminum alloy cast rod.

[0023] Furthermore, the cooling process comprises the following steps:

[0024] The homogenized aluminum alloy cast rod is subjected to wind and mist cooling, and then placed in air to cool to room temperature to obtain the cooled aluminum alloy cast rod.

[0025] Furthermore, the extrusion molding process comprises the following steps:

[0026] The cooled aluminum alloy cast rod is preheated to 480-500° C. and then extruded to obtain the aluminum alloy profile.

[0027] Furthermore, the quenching treatment comprises the following steps:

[0028] The aluminum alloy profile is cooled by water mist and then by water cooling to obtain the quenched aluminum alloy.

[0029] Furthermore, the aging treatment includes the following steps:

[0030] The quenched aluminum alloy is heated to 160-180° C. and kept warm for 6-16 hours to obtain the high-strength 6 series aluminum alloy for automobile anti-collision beams.

[0031] The aluminum alloy prepared by the chemical composition provided by the above technical solution has excellent aging state, tensile strength, yield strength, elongation and tensile strength drop after 30 days; specifically, Al-Mg-Si is an aluminum alloy that can be strengthened by heat treatment, and strengthening phases such as β and β" can be obtained through certain heat treatment, among which β" is the main strengthening phase of the alloy peak aging, and when -0.2≤Si-1.33Mg≤0, it can promote the precipitation of β" inside the alloy gold, but when the Si content exceeds a certain amount, it will precipitate in the form of a single substance, and the presence of single silicon will affect the strength and toughness of the alloy; adding a certain amount of Mn to the alloy with excess Si, Mn and Si form the AlMnSi second phase, which can consume part of the excess Si, and the increase in Mn content promotes the transformation of needle-shaped β-AlMnSi to granular α-AlMnSi, which can improve the impact toughness and bending properties of the alloy. The contents of Mg, Si and Mn in the present invention need to be controlled according to certain strict constraints. system to ensure the effective formation of dispersion-strengthened phase and coarse second phase inside the alloy; further, the solubility of Mg2Si in the aluminum matrix decreases with decreasing temperature. At a temperature of 595°C, the maximum solubility in the aluminum matrix is ​​1.85, while at a temperature of 200°C, the solubility is only 0.25%; Cu and Mg can form AlCuMg phase, which can improve the solubility of Mg in the alloy to a certain extent; in the early stage of aging, the Cu element combines with vacancies to hinder the precipitation of clusters, which can alleviate the adverse effect of the alloy's strength reduction due to the parking effect; further, the Ti element and the V element can interact with each other to compensate for the spatial defects of the aluminum alloy; therefore, the contents of Mg, Si, Cu, Ti and V need to be subject to certain strict constraints, specifically 0.8≤Mg / Si≤1.2, -0.2≤Si-1.33Mg≤0, -0.4≤Mg-1.02Si-0.3Cu≤-0.2, 1.5≤Ti / V≤2.5. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with its embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] A high-strength 6-series aluminum alloy for an automobile anti-collision beam according to one embodiment of the present invention comprises the following chemical components, based on the total mass of the aluminum alloy:

[0035] Si: 0.80-1.20%, Mg: 0.70-1.15%, Cu: 0.15-0.80%, Mn: 0.10-0.50%, Cr: 0.05-0.20%, Ti: ≤0.1%, V: ≤0.15%, Fe: ≤0.18%, the balance being Al and unavoidable impurity elements;

[0036] The content of the impurity element is ≤0.15%;

[0037] Among them, 0.8≤Mg / Si≤1.2, -0.2≤Si-1.33Mg≤0, -0.4≤

[0038] Mg-1.02Si-0.3Cu≤-0.2, 1.5≤Ti / V≤2.5.

[0039] Preferably, the aluminum alloy is composed of the following chemical components based on the total mass of the aluminum alloy:

[0040] Si: 0.80-1.20%, Mg: 0.70-1.15%, Cu: 0.15-0.80%, Mn: 0.10-0.50%, Cr: 0.05-0.20%, Ti: ≤0.1%, V: ≤0.15%, Fe: ≤0.18%, the balance being Al and unavoidable impurity elements;

[0041] The content of the impurity element is ≤0.15%;

[0042] Among them, 0.8≤Mg / Si≤0.9, -0.15≤Si-1.33Mg≤-0.1, -0.4≤Mg-1.02Si-0.3Cu≤-0.3, 1.5≤Ti / V≤2.

[0043] In one embodiment, the present technical solution provides a method for preparing a high-strength 6-series aluminum alloy for an automobile anti-collision beam, which comprises the following steps:

[0044] The raw materials are prepared according to the chemical composition, then added into the melting furnace for melting, the melt is refined, degassed and filtered, and then the liquid aluminum alloy is cast into aluminum alloy rods;

[0045] placing the aluminum alloy cast rod in a homogenizing furnace for homogenization treatment to obtain a homogenized aluminum alloy cast rod;

[0046] Cooling the homogenized aluminum alloy cast rod to obtain a cooled aluminum alloy cast rod;

[0047] Extruding the cooled aluminum alloy cast rod to obtain an aluminum alloy profile;

[0048] quenching the aluminum alloy profile to obtain a quenched aluminum alloy;

[0049] Performing aging treatment on the quenched aluminum alloy to obtain the high-strength 6 series aluminum alloy for automobile anti-collision beams;

[0050] The chemical composition is as follows: based on the total mass of the aluminum alloy, Si: 0.80-1.20%, Mg: 0.70-1.15%, Cu: 0.15-0.80%, Mn: 0.10-0.50%, Cr: 0.05-0.20%, Ti: ≤0.1%, V: ≤0.15%, Fe: ≤0.18%, and the balance is Al and unavoidable impurity elements;

[0051] The content of the impurity elements is ≤0.15%; among which, 0.8≤Mg / Si≤1.2, -0.2≤Si-1.33Mg≤0, -0.4≤Mg-1.02Si-0.3Cu≤-0.2, and 1.5≤Ti / V≤2.5.

[0052] In one embodiment, the refining is performed twice.

[0053] In one embodiment, the gas used for degassing is high-purity argon.

[0054] In one embodiment, the filtration is a double-stage filtration.

[0055] In one embodiment, the homogenization process comprises the following steps:

[0056] The aluminum alloy cast rod is placed in a homogenizing furnace, the temperature is set at 500-560° C., and the temperature is kept at 8-16 hours to obtain the homogenized aluminum alloy cast rod.

[0057] In one embodiment, the cooling process comprises the following steps:

[0058] The homogenized aluminum alloy cast rod is subjected to wind and mist cooling, and then placed in air to cool to room temperature to obtain the cooled aluminum alloy cast rod.

[0059] In one embodiment, the extrusion process comprises the following steps:

[0060] The cooled aluminum alloy cast rod is preheated to 480-500° C. and then extruded to obtain the aluminum alloy profile.

[0061] In one embodiment, the quenching treatment comprises the following steps:

[0062] The aluminum alloy profile is cooled by water mist and then by water cooling to obtain the quenched aluminum alloy.

[0063] In one embodiment, the aging treatment comprises the following steps:

[0064] The quenched aluminum alloy is heated to 160-180° C. and kept warm for 6-16 hours to obtain the high-strength 6 series aluminum alloy for automobile anti-collision beams.

[0065] The embodiments of the present invention will be described in detail below with reference to specific examples.

[0066] Example 1:

[0067] The raw materials are formulated according to the chemical composition and then added to a smelting furnace for melting. The melt is refined twice, degassed with high-purity argon and filtered using a double-stage filtration method. The liquid aluminum alloy is then cast into aluminum alloy rods. The aluminum alloy rods are placed in a homogenizing furnace, set at a temperature of 560° C., and kept warm for 7 hours to obtain homogenized aluminum alloy rods. The homogenized aluminum alloy rods are subjected to wind and mist cooling and then cooled in air to room temperature to obtain cooled aluminum alloy rods. The cooled aluminum alloy rods are preheated to 490° C. and then extruded to obtain aluminum alloy profiles. The aluminum alloy profiles are cooled by water mist and then by water cooling to obtain quenched aluminum alloy. The quenched aluminum alloy is heated to 170° C. and kept warm for 12 hours to obtain a high-strength 6 series aluminum alloy for automotive anti-collision beams.

[0068] The chemical composition is: based on the total mass of the aluminum alloy, Si: 1.06%, Mg: 0.85%, Cu: 0.56%, Mn: 0.39%, Cr: 0.09%, Ti: 0.018%, V: 0.008%, Fe: 0.16%, and the remainder is Al and unavoidable impurity elements.

[0069] Example 2:

[0070] The raw materials are formulated according to the chemical composition and then added to a smelting furnace for melting. The melt is refined twice, degassed with high-purity argon and filtered using a double-stage filtration method. The liquid aluminum alloy is then cast into aluminum alloy rods. The aluminum alloy rods are placed in a homogenizing furnace, set at a temperature of 560° C., and kept warm for 7 hours to obtain homogenized aluminum alloy rods. The homogenized aluminum alloy rods are subjected to wind and mist cooling and then cooled in air to room temperature to obtain cooled aluminum alloy rods. The cooled aluminum alloy rods are preheated to 490° C. and then extruded to obtain aluminum alloy profiles. The aluminum alloy profiles are cooled by water mist and then by water cooling to obtain quenched aluminum alloy. The quenched aluminum alloy is heated to 170° C. and kept warm for 12 hours to obtain a high-strength 6 series aluminum alloy for automotive anti-collision beams.

[0071] The chemical composition is: based on the total mass of the aluminum alloy, Si: 1.13%, Mg: 0.93%, Cu: 0.57%, Mn: 0.37%, Cr: 0.1%, Ti: 0.02%, V: 0.012%, Fe: 0.16%, and the remainder is Al and unavoidable impurity elements.

[0072] Example 3:

[0073] The raw materials are formulated according to the chemical composition and then added to a smelting furnace for melting. The melt is refined twice, degassed with high-purity argon and filtered using a double-stage filtration method. The liquid aluminum alloy is then cast into aluminum alloy rods. The aluminum alloy rods are placed in a homogenizing furnace, set at a temperature of 560° C., and kept warm for 7 hours to obtain homogenized aluminum alloy rods. The homogenized aluminum alloy rods are subjected to wind and mist cooling and then cooled in air to room temperature to obtain cooled aluminum alloy rods. The cooled aluminum alloy rods are preheated to 490° C. and then extruded to obtain aluminum alloy profiles. The aluminum alloy profiles are cooled by water mist and then by water cooling to obtain quenched aluminum alloy. The quenched aluminum alloy is heated to 170° C. and kept warm for 12 hours to obtain a high-strength 6 series aluminum alloy for automotive anti-collision beams.

[0074] The chemical composition is: based on the total mass of the aluminum alloy, Si: 1.12%, Mg: 0.97%, Cu: 0.42%, Mn: 0.28%, Cr: 0.12%, Ti: 0.021%, V: 0.013%, Fe: 0.18%, and the balance is Al and unavoidable impurity elements.

[0075] Comparative Example 1:

[0076] The raw materials are formulated according to the chemical composition, and then added into a smelting furnace for melting, the melt is refined twice, degassed with high-purity argon and filtered using a double-stage filtration, and then the liquid aluminum alloy is cast into an aluminum alloy cast rod; the aluminum alloy cast rod is placed in a homogenizing furnace, the temperature is set to 560° C., and the heat is maintained for 7 hours to obtain a homogenized aluminum alloy cast rod; the homogenized aluminum alloy cast rod is subjected to wind and mist cooling, and then placed in air to cool to room temperature to obtain a cooled aluminum alloy cast rod; the cooled aluminum alloy cast rod is preheated to 490° C. and then extruded to obtain an aluminum alloy profile; the aluminum alloy profile is cooled by water mist and then by water cooling to obtain a quenched aluminum alloy; the quenched aluminum alloy is heated to 170° C. and maintained for 12 hours to obtain an aluminum alloy;

[0077] The chemical composition is: based on the total mass of the aluminum alloy, Si: 1.15%, Mg: 1.05%, Cu: 0.44%, Mn: 0.42%, Cr: 0.19%, Ti: 0.022%, V: 0.012%, Fe: 0.17%, and the balance is Al and unavoidable impurity elements.

[0078] Comparative Example 2:

[0079] The raw materials are formulated according to the chemical composition, and then added into a smelting furnace for melting, the melt is refined twice, degassed with high-purity argon and filtered using a double-stage filtration, and then the liquid aluminum alloy is cast into an aluminum alloy cast rod; the aluminum alloy cast rod is placed in a homogenizing furnace, the temperature is set to 560° C., and the heat is maintained for 7 hours to obtain a homogenized aluminum alloy cast rod; the homogenized aluminum alloy cast rod is subjected to wind and mist cooling, and then placed in air to cool to room temperature to obtain a cooled aluminum alloy cast rod; the cooled aluminum alloy cast rod is preheated to 490° C. and then extruded to obtain an aluminum alloy profile; the aluminum alloy profile is cooled by water mist and then by water cooling to obtain a quenched aluminum alloy; the quenched aluminum alloy is heated to 170° C. and maintained for 12 hours to obtain an aluminum alloy;

[0080] The chemical composition is: based on the total mass of the aluminum alloy, Si: 0.96%, Mg: 0.94%, Cu: 0.22%, Mn: 0.43%, Cr: 0.09%, Ti: 0.027%, V: 0.015%, Fe: 0.15%, and the balance is Al and unavoidable impurity elements.

[0081] Comparative Example 3:

[0082] The raw materials are formulated according to the chemical composition, and then added into a smelting furnace for melting, the melt is refined twice, degassed with high-purity argon and filtered using a double-stage filtration, and then the liquid aluminum alloy is cast into an aluminum alloy cast rod; the aluminum alloy cast rod is placed in a homogenizing furnace, the temperature is set to 560° C., and the heat is maintained for 7 hours to obtain a homogenized aluminum alloy cast rod; the homogenized aluminum alloy cast rod is subjected to wind and mist cooling, and then placed in air to cool to room temperature to obtain a cooled aluminum alloy cast rod; the cooled aluminum alloy cast rod is preheated to 490° C. and then extruded to obtain an aluminum alloy profile; the aluminum alloy profile is cooled by water mist and then by water cooling to obtain a quenched aluminum alloy; the quenched aluminum alloy is heated to 170° C. and maintained for 12 hours to obtain an aluminum alloy;

[0083] The chemical composition is: based on the total mass of the aluminum alloy, Si: 0.87%, Mg: 1.13%, Cu: 0.51%, Mn: 0.36%, Cr: 0.11%, Ti: 0.017%, V: 0.011%, Fe: 0.18%, and the balance is Al and unavoidable impurity elements.

[0084] Comparative Example 4:

[0085] The raw materials are formulated according to the chemical composition, and then added into a smelting furnace for melting, the melt is refined twice, degassed with high-purity argon and filtered using a double-stage filtration, and then the liquid aluminum alloy is cast into an aluminum alloy cast rod; the aluminum alloy cast rod is placed in a homogenizing furnace, the temperature is set to 560° C., and the heat is maintained for 7 hours to obtain a homogenized aluminum alloy cast rod; the homogenized aluminum alloy cast rod is subjected to wind and mist cooling, and then placed in air to cool to room temperature to obtain a cooled aluminum alloy cast rod; the cooled aluminum alloy cast rod is preheated to 490° C. and then extruded to obtain an aluminum alloy profile; the aluminum alloy profile is cooled by water mist and then by water cooling to obtain a quenched aluminum alloy; the quenched aluminum alloy is heated to 170° C. and maintained for 12 hours to obtain an aluminum alloy;

[0086] The chemical composition is: based on the total mass of the aluminum alloy, Si: 1.04%, Mg: 0.70%, Cu: 0.15%, Mn: 0.39%, Cr: 0.13%, Ti: 0.021%, V: 0.009%, Fe: 0.15%, and the remainder is Al and unavoidable impurity elements.

[0087] Comparative Example 5:

[0088] The raw materials are formulated according to the chemical composition, and then added into a smelting furnace for melting, the melt is refined twice, degassed with high-purity argon and filtered using a double-stage filtration, and then the liquid aluminum alloy is cast into an aluminum alloy cast rod; the aluminum alloy cast rod is placed in a homogenizing furnace, the temperature is set to 560° C., and the heat is maintained for 7 hours to obtain a homogenized aluminum alloy cast rod; the homogenized aluminum alloy cast rod is subjected to wind and mist cooling, and then placed in air to cool to room temperature to obtain a cooled aluminum alloy cast rod; the cooled aluminum alloy cast rod is preheated to 490° C. and then extruded to obtain an aluminum alloy profile; the aluminum alloy profile is cooled by water mist and then by water cooling to obtain a quenched aluminum alloy; the quenched aluminum alloy is heated to 170° C. and maintained for 12 hours to obtain an aluminum alloy;

[0089] The chemical composition is: based on the total mass of the aluminum alloy, Si: 1.07%, Mg: 0.93%, Cu: 0.62%, Mn: 0.42%, Cr: 0.13%, Ti: 0.021%, V: 0.007%, Fe: 0.17%, and the balance is Al and unavoidable impurity elements.

[0090] Comparative Example 6:

[0091] The raw materials are formulated according to the chemical composition, and then added into a smelting furnace for melting, the melt is refined twice, degassed with high-purity argon and filtered using a double-stage filtration, and then the liquid aluminum alloy is cast into an aluminum alloy cast rod; the aluminum alloy cast rod is placed in a homogenizing furnace, the temperature is set to 560° C., and the heat is maintained for 7 hours to obtain a homogenized aluminum alloy cast rod; the homogenized aluminum alloy cast rod is subjected to wind and mist cooling, and then placed in air to cool to room temperature to obtain a cooled aluminum alloy cast rod; the cooled aluminum alloy cast rod is preheated to 490° C. and then extruded to obtain an aluminum alloy profile; the aluminum alloy profile is cooled by water mist and then by water cooling to obtain a quenched aluminum alloy; the quenched aluminum alloy is heated to 170° C. and maintained for 12 hours to obtain an aluminum alloy;

[0092] The chemical composition is: based on the total mass of the aluminum alloy, Si: 1.09%, Mg: 0.91%, Cu: 0.53%, Mn: 0.38%, Cr: 0.15%, Ti: 0.007%, V: 0.008%, Fe: 0.16%, and the remainder is Al and unavoidable impurity elements.

[0093] The aluminum alloys obtained in Examples 1 to 3 and Comparative Examples 1 to 6 were tested for aging state, tensile strength, yield strength and elongation. The test results are shown in Table 1.

[0094] Table 1:

[0095]

[0096] As can be seen from Table 1, the aluminum alloys prepared by using the chemical composition provided by the present invention in Examples 1 to 3 have excellent aging state, tensile strength, yield strength, elongation and tensile strength drop after 30 days. Specifically, Al-Mg-Si is an aluminum alloy that can be strengthened by heat treatment. Strengthening phases such as β and β" can be obtained through certain heat treatments, among which β" is the main strengthening phase during peak aging of the alloy. When the Si content in the alloy is excessive, that is, Mg / Si <1.33, the precipitation of β" inside the alloy can be promoted, but when the Si content exceeds 1.33, the precipitation of β" inside the alloy can be promoted. When a certain amount of silicon is present, it will precipitate in the form of a single substance. The presence of single silicon will affect the strength and toughness of the alloy. When a certain amount of Mn is added to an alloy with excess Si, Mn and Si form an AlMnSi second phase, which can consume part of the excess Si. The increase in Mn content will promote the transformation of needle-shaped β-AlMnSi into granular α-AlMnSi, which can improve the impact toughness and bending properties of the alloy. The contents of Mg, Si and Mn in the present invention must be in a strict constraint relationship to ensure the effective formation of the dispersion-strengthened phase and coarse second phase inside the alloy. ; Furthermore, the solubility of Mg2Si in the aluminum matrix decreases with decreasing temperature. When the temperature is 595℃, the maximum solubility in the aluminum matrix is ​​1.85, while at 200℃, the solubility is only 0.25%; Cu and Mg can form AlCuMg phase, which can improve the solubility of Mg in the alloy to a certain extent; in the early stage of aging, Cu combines with vacancies to hinder the precipitation of clusters, which can alleviate the adverse effects of the alloy's strength reduction due to the parking effect; further, Ti and V can interact with each other to compensate for the poor performance of aluminum alloys. Gold spatial defects; therefore, the contents of Mg, Si, Cu, Ti, and V must adhere to certain strict constraints: 0.8 ≤ Mg / Si ≤ 1.2, -0.2 ≤ Si-1.33Mg ≤ 0, -0.4 ≤ Mg-1.02Si-0.3Cu ≤ -0.2, and 1.5 ≤ Ti / V ≤ 2.5. The aluminum alloy properties of Examples 1-3 and Comparative Examples 1-6 show that this constraint significantly affects the aluminum alloy's aging state, tensile strength, yield strength, elongation, and tensile strength degradation after 30 days.

[0097] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A high-strength 6-series aluminum alloy for automobile anti-collision beams, characterized in that: Taking the total mass of aluminum alloy as 100%, it has the following chemical composition composition: Si: 0.80-1.20%, Mg: 0.70-1.15%, Cu: 0.15-0.80%, Mn: 0.10-0.50%, Cr: 0.05-0.20%, Ti: ≤0.1%, V: ≤0.15%, Fe: ≤0.18%, the balance being Al and unavoidable impurity elements; The content of the impurity element is ≤0.15%; Among them, 0.8≤Mg / Si≤1.2, -0.2≤Si-1.33Mg≤0, -0.4≤Mg-1.02Si-0.3Cu≤-0.2, 1.5≤Ti / V≤2.

5.

2. A method for preparing the high-strength 6-series aluminum alloy for automobile anti-collision beams according to claim 1, characterized in that: It includes the following steps: The raw materials are prepared according to the chemical composition, then added into the melting furnace for melting, the melt is refined, degassed and filtered, and then the liquid aluminum alloy is cast into aluminum alloy rods; placing the aluminum alloy cast rod in a homogenizing furnace for homogenization treatment to obtain a homogenized aluminum alloy cast rod; Cooling the homogenized aluminum alloy cast rod to obtain a cooled aluminum alloy cast rod; Extruding the cooled aluminum alloy cast rod to obtain an aluminum alloy profile; quenching the aluminum alloy profile to obtain a quenched aluminum alloy; Performing aging treatment on the quenched aluminum alloy to obtain the high-strength 6 series aluminum alloy for automobile anti-collision beams; The chemical composition is as follows: based on the total mass of the aluminum alloy, Si: 0.80-1.20%, Mg: 0.70-1.15%, Cu: 0.15-0.80%, Mn: 0.10-0.50%, Cr: 0.05-0.20%, Ti: ≤0.1%, V: ≤0.15%, Fe: ≤0.18%, and the balance is Al and unavoidable impurity elements; The content of the impurity elements is ≤0.15%; among which, 0.8≤Mg / Si≤1.2, -0.2≤Si-1.33Mg≤0, -0.4≤Mg-1.02Si-0.3Cu≤-0.2, and 1.5≤Ti / V≤2.

5.

3. The preparation method according to claim 2, characterized in that The refining was performed twice.

4. The preparation method according to claim 2, characterized in that The gas used for the degassing is high-purity argon.

5. The preparation method according to claim 2, characterized in that The filtration adopts double-stage filtration.

6. The preparation method according to claim 2, characterized in that The homogenization process comprises the following steps: The aluminum alloy cast rod is placed in a homogenizing furnace, the temperature is set at 500-560° C., and the temperature is kept at 8-16 hours to obtain the homogenized aluminum alloy cast rod.

7. The preparation method according to claim 2, characterized in that The cooling process comprises the following steps: The homogenized aluminum alloy cast rod is subjected to wind and mist cooling, and then placed in air to cool to room temperature to obtain the cooled aluminum alloy cast rod.

8. The preparation method according to claim 2, characterized in that The extrusion molding process comprises the following steps: The cooled aluminum alloy cast rod is preheated to 480-500° C. and then extruded to obtain the aluminum alloy profile.

9. The preparation method according to claim 2, characterized in that The quenching treatment comprises the following steps: The aluminum alloy profile is cooled by water mist and then by water cooling to obtain the quenched aluminum alloy.

10. The preparation method according to claim 2, characterized in that The aging treatment comprises the following steps: The quenched aluminum alloy is heated to 160-180° C. and kept warm for 6-16 hours to obtain the high-strength 6 series aluminum alloy for automobile anti-collision beams.

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