Aluminum alloy for manufacturing automobile skylight guide rail and production process thereof

Abstract

The invention discloses an aluminum alloy for manufacturing an automobile skylight guide rail and a production process thereof, and the aluminum alloy comprises the following components in percentage by mass: 0.3-0.7% of Si, less than or equal to 0.6% of Fe, less than or equal to 0.2% of Cu, 0.05-0.15% of Mn, 0.47-0.53% of Mg, less than or equal to 0.15% of Zn, less than or equal to 0.1% of Ti, 0.15-0.25% of Cr, less than or equal to 0.05% of other single impurities, less than or equal to 0.15% of total impurities, and the balance of Al. According to the aluminum alloy subjected to heat treatment, the tensile strength can be larger than or equal to 260 MPa, the yield strength is larger than or equal to 240 MPa, the aluminum alloy is suitable for scenes needing structural support but not ultrahigh strength, and the problem of deformation can be effectively solved when the skylight guide rail is used. And meanwhile, a compact Al2O3 oxidation film is easily generated on the surface of the aluminum matrix, so that excellent corrosion resistance is achieved, corrosion to the skylight guide rail in the using process can be reduced, and the reliability and safety of the skylight guide rail are greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloys, and in particular relates to an aluminum alloy for manufacturing an automobile sunroof guide rail, and a production process of the aluminum alloy for manufacturing the automobile sunroof guide rail. Background Art

[0002] As a key component of the car sunroof system, the car sunroof guide rail needs to have good mechanical properties, corrosion resistance and processing performance. Currently, the material used to manufacture the car sunroof guide rail on the market is mostly aluminum alloy.

[0003] However, existing aluminum alloys still have certain performance deficiencies. For example, some aluminum alloys lack sufficient strength and hardness, leading to deformation and wear of sunroof rails over time, impacting the normal operation and lifespan of the sunroof. Furthermore, some aluminum alloys lack corrosion resistance and are susceptible to corrosion in harsh environments such as humidity, acidity, and alkalinity, reducing the reliability and safety of the sunroof rails. Summary of the Invention

[0004] The present invention addresses the problem that the strength and hardness of aluminum alloy in the prior art are not high enough, resulting in the sunroof guide rail being easily deformed and worn during long-term use. The present invention proposes the following technical solutions:

[0005] The aluminum alloy used for manufacturing automobile sunroof guide rails is composed of the following components in percentage by mass: Si 0.3-0.7%, Fe ≤ 0.6%, Cu ≤ 0.2%, Mn 0.05-0.15%, Mg 0.47-0.53%, Zn ≤ 0.15%, Ti ≤ 0.1%, Cr 0.15-0.25%, other single impurities: ≤ 0.05%, total impurities: ≤ 0.15%, and the remainder is Al.

[0006] A method for preparing an aluminum alloy for manufacturing a sunroof guide rail for an automobile, comprising:

[0007] S1. Ingredients: According to the mass percentage of the above aluminum alloy formula, accurately weigh the raw materials of various alloy elements to ensure that the purity of the raw materials meets the requirements to ensure the quality of the alloy.

[0008] S2. Melting: Add the weighed raw materials into the melting furnace and heat to 720℃-750℃ to fully melt the alloy elements.

[0009] S3. Casting: The refined alloy liquid is temperature controlled at 700℃-720℃, and then cast into a specific mold to make the required ingot.

[0010] S4. Homogenizing annealing: Place the ingot into an annealing furnace for homogenizing annealing at a temperature of 550-570°C for 4-6 hours.

[0011] As a preferred embodiment of the above technical solution, it also includes:

[0012] S5. Extrusion molding: The ingot after homogenization annealing is heated to 480°C-520°C, and then extruded on an extruder to form the profile required for the automobile sunroof guide rail.

[0013] As a preferred embodiment of the above technical solution, it also includes:

[0014] S6. Aging treatment: The extruded profile is subjected to aging treatment at an aging temperature of 170°C-190°C for 6-8 hours.

[0015] As a preferred embodiment of the above technical solution, in the step S2, during the smelting process, an inert gas such as argon is introduced for refining to remove gas and inclusions in the alloy liquid, and electromagnetic stirring and other methods are used to homogenize the composition of the alloy liquid.

[0016] The beneficial effects of the present invention are:

[0017] 1. The synergistic effect of Ti and Cr achieves dual optimization of grain refinement and corrosion resistance, significantly improving the strength of the aluminum alloy. After heat treatment, the aluminum alloy can achieve a tensile strength of ≥260MPa and a yield strength of ≥240MPa, making it suitable for applications requiring structural support but not ultra-high strength. It can also reduce deformation when used in sunroof rails, while spraying an additional coating effectively addresses wear resistance, reducing costs while ensuring the aluminum alloy meets performance requirements.

[0018] 2. A dense Al2O3 oxide film is easily formed on the surface of the aluminum substrate, which has excellent corrosion resistance, better than carbon steel and low alloy steel. It has good corrosion resistance to fresh water, atmosphere, food and other environments, reducing the corrosion of the sunroof guide rail during use, thereby greatly improving the reliability and safety of the sunroof guide rail. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shown is a diagram of the proportions of an embodiment. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments and the accompanying drawings.

[0021] The aluminum alloy used for manufacturing automobile sunroof guide rails is composed of the following components in percentage by mass: Si 0.3-0.7%, Fe ≤ 0.6%, Cu ≤ 0.2%, Mn 0.05-0.15%, Mg 0.47-0.53%, Zn ≤ 0.15%, Ti ≤ 0.1%, Cr 0.15-0.25%, other single impurities: ≤ 0.05%, total impurities: ≤ 0.15%, and the remainder is Al.

[0022] Adding Ti can inhibit intergranular corrosion and improve corrosion resistance. Ti and Al form an Al3Ti dispersed phase, which acts as a heterogeneous nucleation core, inhibiting excessive grain growth during casting and making the alloy structure finer. Furthermore, during hot extrusion or forging, the tiny Ti particles pin the grain boundaries, hindering the growth of recrystallized grains and maintaining the processed fibrous structure, which can inhibit recrystallization and stabilize hot working properties.

[0023] Adding Cr can inhibit intergranular corrosion and improve corrosion resistance. Cr in solid solution increases the electrode potential of the aluminum matrix and forms a (Fe,Cr)Al6 composite phase at the grain boundaries, replacing the easily corroded pure FeAl3 phase and reducing the formation of aluminum-depleted regions at the grain boundaries. Furthermore, Cr has a low diffusion coefficient in Al and forms a CrAl7 dispersed phase during aging, pinning dislocation motion and producing a dispersion strengthening effect. While aging strengthens and improves heat resistance, the fine particles formed by Cr hinder the growth of recrystallized grains, inhibiting recrystallization and stabilizing hot working properties.

[0024] The synergistic effect of Ti and Cr achieves dual optimization of grain refinement and corrosion resistance, significantly improving the strength of the aluminum alloy. After heat treatment, the aluminum alloy can achieve a tensile strength of ≥260MPa and a yield strength of ≥240MPa, making it suitable for scenarios requiring structural support but not ultra-high strength. Its good plasticity allows it to be formed into complex shapes through processes such as extrusion, forging, and cutting, making it suitable for mass production. Although its wear resistance is average, additional coatings (such as hard anodizing) can be used for friction parts, reducing costs while ensuring that the aluminum alloy meets usage requirements.

[0025] Aluminum alloy This aluminum alloy has the advantage of lightweight: density is about 2.7g / cm 3 , which is only 1 / 3 of steel, making it easy to reduce the weight of the overall structure and suitable for lightweight demand scenarios such as aerospace, new energy vehicles, etc.

[0026] Aluminum alloy This aluminum alloy has good thermal conductivity: thermal conductivity is about 167W / (m·K), and can be used for heat dissipation components.

[0027] A dense Al2O3 oxide film is easily formed on the surface of the aluminum substrate, which has excellent corrosion resistance and good corrosion resistance to fresh water, atmosphere, food and other environments. It is better than carbon steel and low-alloy steel, reducing the corrosion of the skylight guide rail during use, thereby greatly improving the reliability and safety of the skylight guide rail.

[0028] A method for preparing an aluminum alloy for manufacturing a sunroof guide rail for an automobile, comprising:

[0029] S1. Ingredients: According to the mass percentage of the above aluminum alloy formula, accurately weigh the raw materials of various alloy elements to ensure that the purity of the raw materials meets the requirements to ensure the quality of the alloy.

[0030] S2. Melting: Add the weighed raw materials into the melting furnace and heat to 720℃-750℃ to fully melt the alloy elements.

[0031] S3. Casting: The refined alloy liquid is temperature controlled at 700℃-720℃, and then cast into a specific mold to make the required ingot.

[0032] S4. Homogenizing annealing: Place the ingot into an annealing furnace for homogenizing annealing at a temperature of 550-570°C for 4-6 hours.

[0033] Also includes:

[0034] S5. Extrusion molding: The ingot after homogenization annealing is heated to 480°C-520°C, and then extruded on an extruder to form the profile required for the automobile sunroof guide rail.

[0035] Also includes:

[0036] S6. Aging treatment: The extruded profile is subjected to aging treatment at an aging temperature of 170°C-190°C for 6-8 hours.

[0037] In the step S2, during the smelting process, an inert gas such as argon is introduced for refining to remove gas and inclusions in the alloy liquid, and electromagnetic stirring is used to homogenize the composition of the alloy liquid.

[0038] Example 1:

[0039] 1. Chemical composition (wt%)

[0040] element Si Fe Cu Mn Mg content 0.5 ≤0.5 0.15 0.12 0.53 element Zn Ti Cr Total impurities Al content ≤0.1 0.08 0.25 ≤0.15 the remaining

[0041] 2. Production process

[0042] Melting and casting:

[0043] 99.7% pure aluminum ingot is used as the base material, and intermediate alloys such as Mg, Si, Cr are added in proportion. The melting temperature is controlled at 720-750°C, and Ar gas is introduced for refining and degassing for 15 minutes. After standing and slagging, it is cast into φ150mm ingot.

[0044] Homogenization treatment:

[0045] The ingot was kept at 520 °C for 8 hours and then cooled to room temperature in the furnace to eliminate casting stress and homogenize the structure.

[0046] Extrusion molding:

[0047] Heat to 480℃ and extrude into skylight track profile at an extrusion speed of 5 to 8 m / min.

[0048] Heat treatment:

[0049] T6 aging: solution treatment (535℃×1 hour water quenching) + artificial aging (175℃×8 hours) to improve strength.

[0050] Surface treatment:

[0051] Hard anodizing (film thickness 25μm) improves wear resistance and corrosion resistance.

[0052] 3. Performance characteristics

[0053] Mechanical properties:

[0054] Tensile strength: 300MPa, yield strength: 270MPa, elongation: 12%, hardness (HB): 110.

[0055] Advantages:

[0056] High strength and lightweight balance (density 2.7g / cm 3 ), and its fatigue resistance is better than that of conventional 6061 aluminum alloy.

[0057] limitation:

[0058] The corrosion resistance of marine environment is average (additional coating protection is required).

[0059] Example 2:

[0060] 1. Chemical composition (wt%)

[0061]

[0062]

[0063] 2. Production process

[0064] Melting and casting:

[0065] Aluminum ingots with low Fe impurities (Fe≤0.35%) were used, Mg2Si master alloy was added to control the Si / Mg ratio to ≈0.74, the melting temperature was 710-730°C, and 0.02% Sr modifier was added to refine the silicon phase.

[0066] Homogenization treatment:

[0067] 510℃×6 hours, air cooling to reduce grain boundary precipitates.

[0068] Extrusion molding:

[0069] Heat to 460℃ and extrude into skylight track profile (complex cross-section) at an extrusion speed of 10-12m / min, retaining the surface extrusion lubrication layer (temporary anti-oxidation).

[0070] Heat treatment:

[0071] T4 state: solution treatment (525℃×1 hour water quenching) + natural aging (room temperature for 72 hours), retaining plasticity for subsequent bending processing.

[0072] Surface treatment:

[0073] Powder coating (polyester coating thickness 60μm) provides double anti-corrosion protection.

[0074] 3. Performance characteristics

[0075] Mechanical properties:

[0076] Tensile strength: 240MPa, yield strength: 180MPa, elongation: 18%, hardness (HB): 85.

[0077] Advantages:

[0078] Low sensitivity to intergranular corrosion (low Cu and Fe content), no corrosion spots after 500 hours of salt spray test (ASTM B117).

[0079] limitation:

[0080] The strength is lower than that of T6 treated alloy and is not suitable for high load scenarios.

[0081] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same.

Claims

1. Aluminum alloy for manufacturing automobile sunroof guide rails, characterized in that: The aluminum alloy is composed of the following components by mass percentage: Si 0.3-0.7%, Fe≤0.6%, Cu≤0.2%, Mn 0.05-0.15%, Mg 0.47-0.53%, Zn≤0.15%, Ti≤0.1%, Cr 0.15-0.25%, other single impurities: ≤0.05%, total impurities: ≤0.15%, and the remainder is Al content.

2. A method for preparing an aluminum alloy for manufacturing a sunroof guide rail for an automobile according to claim 1, characterized in that: The following steps are involved: S1. Ingredients: According to the mass percentage of the above aluminum alloy formula, accurately weigh the raw materials of various alloy elements to ensure that the purity of the raw materials meets the requirements to ensure the quality of the alloy. S2. Melting: Add the weighed raw materials into the melting furnace and heat to 720℃-750℃ to fully melt the alloy elements. S3. Casting: The refined alloy liquid is temperature controlled at 700℃-720℃, and then cast into a specific mold to make the required ingot. S4. Homogenizing annealing: Place the ingot into an annealing furnace for homogenizing annealing at a temperature of 550-570°C for 4-6 hours.

3. The method for preparing the aluminum alloy for manufacturing the automobile sunroof guide rail according to claim 2, characterized in that: Also includes: S5. Extrusion molding: The ingot after homogenization annealing is heated to 480°C-520°C, and then extruded on an extruder to form the profile required for the automobile sunroof guide rail.

4. The method for preparing an aluminum alloy for manufacturing a sunroof guide rail for an automobile according to claim 2, wherein: Also includes: S6. Aging treatment: The extruded profile is subjected to aging treatment at an aging temperature of 170°C-190°C for 6-8 hours.

5. The aluminum alloy for manufacturing automobile sunroof guide rails according to claim 2, characterized in that: In the step S2, during the smelting process, an inert gas such as argon is introduced for refining to remove gas and inclusions in the alloy liquid, and electromagnetic stirring is used to homogenize the composition of the alloy liquid.

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