High-sandblasted anodized appearance 6-series aluminum alloy and processing technology thereof

Abstract

The application discloses a high-sandblasting anode appearance 6-series aluminum alloy and a processing technology thereof. The aluminum alloy is cast according to the following components: Mg 0.4-1.0 wt.%, Si 0.4-1.5 wt.%, Cu 0.05-1.3 wt.%, Mn 0.02-0.10 wt.%, Fe≤0.2 wt.%, Cr≤0.2 wt.%, Ti 0.005-0.05 wt.%, and the rest components are Al and inevitable impurities, and then the aluminum alloy is subjected to homogenization, extrusion forming and aging treatment. The content of elements such as Mg, Si, Cu, Mn and Ti is adjusted and the process is controlled, so that the aluminum alloy material has relatively fine grains, thereby obtaining a high-sandblasting anode appearance effect, and meanwhile, the aluminum alloy material has relatively high strength and relatively high extrusion processing efficiency, and is suitable for application in the field of consumer electronic aluminum materials.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy preparation technology, and in particular to a high-sandblasting anodic appearance 6-series aluminum alloy and its processing technology. Background Technology

[0002] During the sandblasting and anodizing process, 6-series aluminum alloys are prone to developing "material streaks" and "mottling" due to coarse grains. "Material streaks" are fine, strip-like lines along the direction of processing deformation, mainly caused by the ineffective control of the size and distribution of intermetallic compounds in the material; "mottling" is formed in the aluminum alloy during the anodizing process due to coarse grains. Currently, the technical solutions for controlling grain size in aluminum alloy processing still have shortcomings and their effectiveness needs improvement. For example, patent CN202211233119.4 discloses a high-strength fine-grained aluminum alloy containing Zr and its preparation process, with grain size reaching 6-8 levels. However, the material contains a large number of transition elements, which easily causes sandblasting anodizing defects. Patent CN202211101463.8 discloses a high-strength and tough fine-grained aluminum alloy containing Mn / Cr. Similarly, due to the presence of a large number of transition elements, it is also prone to sandblasting anodizing defects. Patent CN201910532998.2 discloses an aluminum alloy containing rare earth Ce, but this significantly increases material costs and also easily causes sandblasting anodizing defects. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a high-quality sandblasted anodized 6-series aluminum alloy and its processing technology. This material has finer grains and a high-quality sandblasted anodized appearance, making it suitable for consumer electronics aluminum applications.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A high-anode blasting 6-series aluminum alloy, by mass percentage, comprises: Mg 0.4–1.0 wt.%, Si 0.4–1.5 wt.%, Cu 0.05–1.3 wt.%, Mn 0.02–0.10 wt.%, Fe ≤0.2 wt.%, Cr ≤0.2 wt.%, Ti 0.005–0.05 wt.%, unavoidable impurities ≤0.5 wt.%, and the balance being Al.

[0006] Furthermore, the density of the dispersed phase in the microstructure of the 6-series aluminum alloy is greater than 3 × 10⁻⁶. 5 pcs / mm 2 .

[0007] The above-mentioned high-sandblasting anodized 6-series aluminum alloy processing technology includes the following steps:

[0008] Raw materials are weighed according to the mass percentage of each element in the aluminum alloy composition and then smelted and cast to obtain ingots.

[0009] The ingots with the above-mentioned composition are subjected to homogenization treatment, and then heated from room temperature to 400-460°C at a heating rate of 10°C-30°C / h and held at that temperature for 20-30h; then heated to 540-570°C at a heating rate of 10°C-30°C / h and held at that temperature for 10-30h; then cooled to 400°C at a heating rate of 5°C-10°C / h and then cooled to room temperature.

[0010] The homogenized material is extruded at an extrusion bar temperature of 500–560°C and an extruded material exit temperature of 480–520°C.

[0011] The extruded material is subjected to aging treatment.

[0012] Furthermore, the homogenized material is extruded at a speed ≥10m / min.

[0013] In 6-series aluminum alloys, Mg, Si, and Cu are the main additive elements, and their content levels determine the mechanical properties of the material. Higher additions result in higher strength, but excessive alloying content can lead to an excessive number of compounds in the material, causing sandblasting and anodizing marks. Overall, Mg, Si, and Cu contents of 0.4–1.0 wt.%, 0.4–1.5 wt.%, and 0.05–1.3 wt.%, respectively, achieve a balance between high strength and the avoidance of sandblasting marks.

[0014] Mn is a trace element added primarily to control grain size, but it can easily cause streaks in the blasted anode material. Its content should ideally be 0.02–0.1 wt.%. Ti is also a trace element primarily to control as-cast grains. The compounds formed by Ti are finer and denser than those containing Mn, making it easier to control the size of deformed grains. Its content of 0.005–0.05 wt. can have a significant impact on grain size control.

[0015] Fe and Cr are impurities, and their contents should ideally be Cr ≤ 0.2 wt.% and Fe ≤ 0.2 wt.%.

[0016] The ingots with the above-mentioned composition were homogenized by heating from room temperature to 400–460°C at a rate of 10–30°C / h and holding for 20–30 h, then heating to 540–570°C at a rate of 10–30°C / h and holding for 10–30 h, then cooling to 400°C at a rate of 5–10°C / h, and finally cooling to room temperature. Controlling the heating rate promotes the uniform nucleation of Mn and Ti phases, while holding at 400–460°C for a period of time promotes the nucleation of dispersed phases; holding at a high temperature of 540–570°C for a period of time dissolves Mg₂Si and promotes the growth of dispersed phases; and controlling the cooling rate helps in the subsequent control of grain size by promoting the formation of dispersed phases.

[0017] Homogeneous materials are extruded, with the extrusion bar temperature at 500–560°C and the extruded material exit temperature at 480–520°C. Controlling the extrusion bar temperature and the extruded material exit temperature is to control the deformation energy and the grain size of the material.

[0018] This invention achieves high strength and fine grains in materials by adjusting the content of elements such as Mg, Si, Cu, Mn, and Ti, and controlling the process, thereby obtaining a high-quality sandblasted anodized appearance. It is suitable for use in consumer electronics aluminum materials. Attached Figure Description

[0019] Figure 1 Example 1 is a 3000x scanning electron microscope image;

[0020] Figure 2 Comparative Example 1 is a 3000x scanning electron microscope image; Detailed Implementation

[0021] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0022] Example 1

[0023] The composition of 6-series aluminum alloys by mass percentage is: Mg 0.4wt.%, Si 1.5wt.%, Mn 0.1wt%, Cr 0.2wt%, Cu 0.05wt.%, Ti 0.05wt%, Fe 0.2wt%, unavoidable impurities ≤0.5wt%, balance Al;

[0024] The raw materials are weighed according to the mass percentage of each element in the above aluminum alloy and then smelted and cast to obtain ingots.

[0025] The ingots with the above composition were homogenized by heating from room temperature to 460°C at a rate of 10°C / h and holding for 30h, then heating to 570°C at a rate of 10°C / h and holding for 10h, then cooling to 400°C at a rate of 10°C / h and then cooling to room temperature.

[0026] The homogeneous material is extruded at an extrusion bar temperature of 560℃, an extruded material outlet temperature of 520℃, and an extrusion speed of 11m / min.

[0027] The extruded material was subjected to aging treatment, and the resulting extruded material was heated to 190℃ at a rate of 10℃ / h and held for 10h.

[0028] Example 2

[0029] The composition of 6-series aluminum alloys, by mass percentage, is: Mg 1.0 wt.%, Si 0.4 wt.%, Mn 0.02 wt%, Cr 0.01 wt%, Cu 1.3 wt.%, Ti 0.005 wt%, Fe 0.06 wt%.

[0030] The raw materials are weighed according to the mass percentage of each element in the above aluminum alloy and then smelted and cast to obtain ingots.

[0031] The ingots with the above composition were homogenized by heating from room temperature to 400℃ at a rate of 30℃ / h and holding for 20h, then heating to 540℃ at a rate of 30℃ / h and holding for 30h, then cooling to 400℃ at a rate of 5℃ / h, and then cooling to room temperature.

[0032] The homogeneous material is extruded at a temperature of 500°C, an extruded material outlet temperature of 480°C, and an extrusion speed of 11 m / min.

[0033] The extruded material was subjected to aging treatment, and the resulting extruded material was heated to 190℃ at a rate of 10℃ / h and held for 10h.

[0034] Example 3

[0035] The composition of 6-series aluminum alloys, by mass percentage, is: Mg 0.8 wt.%, Si 0.9 wt.%, Mn 0.08 wt%, Cr 0.05 wt%, Cu 0.8 wt.%, Ti 0.02 wt%, Fe 0.07 wt%.

[0036] The raw materials are weighed according to the mass percentage of each element in the above aluminum alloy and then smelted and cast to obtain ingots.

[0037] The ingots with the above composition were homogenized by heating from room temperature to 420°C at a rate of 15°C / h and holding for 25h, then heating to 550°C at a rate of 15°C / h and holding for 15h, then cooling to 400°C at a rate of 8°C / h, and then cooling to room temperature.

[0038] The homogeneous material is extruded at an extrusion bar temperature of 530℃, an extruded material outlet temperature of 510℃, and an extrusion speed of 11m / min.

[0039] The extruded material was subjected to aging treatment, and the resulting extruded material was heated to 190℃ at a rate of 10℃ / h and held for 10h.

[0040] Comparative Example 1

[0041] The composition of 6-series aluminum alloys, by mass percentage, is: Mg 0.8wt.%, Si 0.8wt.%, Mn 0.3wt%, Cr 0.40wt%, Cu 0.45wt.%, Ti 0.25wt%, Fe 0.19wt%.

[0042] The processing technology of the aluminum alloy in Comparative Example 1 is the same as that in Example 1.

[0043] Comparative Example 2

[0044] The composition of the aluminum alloy in Comparative Example 2 is the same as that in Example 1.

[0045] The difference lies in the following: the ingots containing the above components are homogenized and held at 580℃ for 30 hours; the homogenized material is then extruded at a bar temperature of 560℃ and an extruded material outlet temperature of 540℃.

[0046] Mechanical properties of the aluminum alloys in Examples 1-3 and Comparative Examples 1-2 were tested according to GB / T6892-2015 "General Industrial Aluminum and Aluminum Alloy Extruded Profiles" and ASTM E112-2013 "Standard Test Method for Determination of Average Grain Size". Table 1 shows the properties and microstructure characteristics of the aluminum alloys in Examples 1-3 and Comparative Examples 1-2. Wherein: Dispersed compound density (cells / mm²) 2 The density of the dispersed compound was calculated by using a 10,000x scanning electron microscope.

[0047] Table 1

[0048]

[0049] As shown in Table 1, this invention inhibits grain growth and refines grains by adding trace elements Mn and Ti to aluminum alloys. Furthermore, by controlling the heat treatment process, it ensures fine grains in the finished product and effectively controls the size and distribution of intermetallic compounds, thus avoiding "spots" and "texture lines" formed on aluminum alloys during the anodizing process due to coarse grains and uneven distribution.

[0050] This invention achieves high strength, high sandblasted anodized appearance, and high extrusion speed by rationally adjusting the content of various elements in aluminum alloys and processing technology, making it suitable for large-scale production of aluminum materials for consumer electronics.

[0051] Based on the disclosure in the foregoing specification, those skilled in the art can make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A 6-series aluminum alloy with a high-quality sandblasted anodized appearance, characterized in that: By mass percentage, it includes: Mg 0.8 wt.%, Si 0.9 wt.%, Cu 0.8 wt.%, Mn 0.08 wt.%, Fe 0.07 wt.%, Cr 0.05 wt.%, Ti 0.02 wt.%, with the remainder being Al and unavoidable impurities; The density of the dispersed phase in the microstructure of the 6-series aluminum alloy is 4.6 × 10⁻⁶. 5 pcs / mm 2 ; The processing technology for the high-sandblasting anodized 6-series aluminum alloy includes the following steps: Raw materials are weighed according to the mass percentage of each element in the aluminum alloy composition and then smelted and cast to obtain ingots. The ingot is homogenized by heating it from room temperature to 420°C at a rate of 15°C / h and holding it at that temperature for 25 hours; then heating it to 550°C at a rate of 15°C / h and holding it at that temperature for 15 hours; then cooling it to 400°C at a rate of 8°C / h and then cooling it back to room temperature. The homogenized material was extruded at an extrusion bar temperature of 530℃, an extruded material outlet temperature of 510℃, and an extrusion speed of 11m / min. The extruded material is subjected to aging treatment by heating it to 190℃ at a rate of 10℃ / h and holding it at that temperature for 10h.

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