A low-alloyed 6-series aluminium alloy and a method of processing thereof

Abstract

The application discloses a low-alloyed 6-series aluminum alloy and a processing method thereof. The aluminum alloy material contains Mg≤0.6 wt.%, Si≤0.6 wt.% and Cu≤0.2 wt.%; and the balance of aluminum and inevitable impurities. After solid solution quenching of the aluminum alloy material, a heat treatment method is adjusted to form a larger volume fraction of a strengthening phase, so that the low-alloyed 6-series aluminum alloy has higher processing performance and improved material strength performance, and the decline of processing performance and corrosion resistance caused by adjusting the composition to improve the performance is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to a low-alloyed 6-series aluminum alloy and a processing method thereof. Background Art

[0002] Low-alloyed 6-series aluminum alloys, such as 6063 and 6060, offer excellent formability and high production efficiency due to their low alloying levels. However, their relatively low strength limits their application to parts requiring minimal strength. The most direct and effective way to improve the strength of 6063 and 6060 alloys is to increase the alloying level, but this also reduces the material's machinability and corrosion resistance. Therefore, a method is needed to improve the material's strength without compromising its machinability. Summary of the Invention

[0003] The purpose of the present invention is to provide a low-alloyed 6-series aluminum alloy and a processing method for improving the strength of the low-alloyed 6-series aluminum alloy in order to meet market demand in view of the deficiencies in the prior art.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] First, the present invention provides an improved low-alloyed 6-series aluminum alloy, which comprises, by mass percentage, Si≤0.6wt.%, Mg≤0.6wt.%, Cu≤0.2wt.%, and the remaining components are Al and unavoidable impurities.

[0006] Furthermore, the low-alloyed 6 series aluminum alloy is 6063 aluminum alloy or 6060 aluminum alloy.

[0007] Secondly, the present invention provides a processing method for improving the strength of a low-alloyed 6-series aluminum alloy, wherein the low-alloyed 6-series aluminum alloy is solution quenched, then stored at room temperature for more than 48 hours, and then subjected to aging treatment at 170-190° C. for 5-20 hours;

[0008] Or the low alloyed 6 series aluminum alloy is solution quenched, then kept at 170-185°C for 15-80 minutes, then kept at ≤80°C for 76-336 hours, and then aged at 170-190°C for 5-20 hours;

[0009] Alternatively, the low-alloyed 6 series aluminum alloy is solution quenched, then kept at room temperature for more than 48 hours, kept at 170-185° C. for 15-80 minutes, then kept at ≤80° C. for 76-336 hours, and then aged at 170-190° C. for 5-20 hours.

[0010] The low-alloyed 6-series aluminum alloy of the present invention contains relatively few strengthening elements, resulting in a relatively small volume fraction of the strengthening phase formed under conventional heat treatment conditions. The low-alloyed 6-series aluminum alloy of the present invention refers to a 6-series aluminum alloy containing Mg ≤ 0.6 wt.%, Si ≤ 0.6 wt.%, and Cu ≤ 0.2 wt.%. 6-series aluminum alloys with contents exceeding these limits have higher strength but poorer processability, slower extrusion speeds, and are prone to cracking.

[0011] On the one hand, after solution quenching, the low-alloyed 6-series aluminum alloy of the present invention is left at room temperature for more than 48 hours. During this process, the quenching vacancies necessary for artificial aging combine with the solute. Furthermore, due to the low degree of alloying, solute diffusion is not significant, so the quenching vacancies are largely preserved and the solute atoms do not form large clusters (large clusters that would affect the subsequent artificial aging effect). During the subsequent artificial aging process, the material left at room temperature exhibits higher aging strength.

[0012] On the other hand, after solution quenching, the low-alloyed 6-series aluminum alloy of the present invention is immediately kept at 170-185°C for 15-80 minutes, first forming small dispersed atomic clusters and fixing vacancies in the clusters. It is then kept at ≤80°C for 76-336 hours, allowing the atomic clusters to grow slowly and stably while maintaining a small size. It is then aged at 170-190°C for 5-20 hours, at which time a strengthening phase with a larger volume fraction can be formed, so the material has higher strength.

[0013] The present invention combines room temperature storage and heat treatment, which can better control the size of atomic clusters before artificial aging, so that a large number of strengthening phases are formed during the artificial aging process, thereby improving the strength performance of the material.

[0014] The beneficial effects of the present invention are:

[0015] The present invention enables the low-alloyed 6 series aluminum alloy to have higher mechanical properties by adjusting the heat treatment process, thereby avoiding the degradation of processing performance and corrosion resistance caused by improving performance by adjusting the composition. DETAILED DESCRIPTION

[0016] In order 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, rather than limiting the claims of the present invention.

[0017] The technical solution of the present invention is further described below through specific embodiments.

[0018] Example 1

[0019] The composition of the 6063 aluminum alloy is as follows, by mass percentage: Mg 0.5 wt.%, Si 0.4 wt.%, Cu 0.01 wt.%, and the remaining components are Al and inevitable impurities.

[0020] The processing method of the above-mentioned 6063 aluminum alloy includes:

[0021] Weigh raw materials according to the mass percentage of each element in the above aluminum alloy composition, and perform smelting and casting to obtain an ingot;

[0022] The ingot was subjected to homogenization annealing, the ingot was kept at 560 °C for 12 h, and then air-cooled to room temperature;

[0023] After homogenization, the material was extruded with a rod temperature of 540°C, an extruded material outlet temperature of 550°C, and an extrusion speed of 10.5 m / min.

[0024] The extruded aluminum alloy material was solution quenched at a solution temperature of 560°C for 1 h, and then water-cooled to room temperature.

[0025] After quenching, the aluminum alloy was kept at room temperature for 72 hours and then subjected to aging treatment at 185°C for 12 hours.

[0026] Example 2

[0027] The composition of the 6063 aluminum alloy is as follows, by mass percentage: Mg=0.5 wt.%, Si=0.4 wt.%, Cu=0.01 wt.%, and the remaining components are Al and unavoidable impurities.

[0028] After quenching, the aluminum alloy was kept at room temperature for 168 hours and then subjected to aging treatment at 185° C. for 12 hours. Other processing techniques were the same as those in Example 1.

[0029] Example 3

[0030] The composition of the 6063 aluminum alloy is as follows, in percentage by mass: Mg=0.45 wt.%, Si=0.4 wt.%, Cu=0.01 wt.%, and the remaining components are Al and unavoidable impurities.

[0031] After quenching, the aluminum alloy was immediately kept at 170° C. for 80 minutes, then kept at 60° C. for 76 hours, and then aged at 170° C. for 20 hours. Other processing techniques were the same as those in Example 1.

[0032] Example 4

[0033] The composition of the 6063 aluminum alloy is as follows, in percentage by mass: Mg=0.5 wt.%, Si=0.4 wt.%, Cu=0.01 wt.%, and the remaining components are Al and unavoidable impurities.

[0034] After quenching, the aluminum alloy is immediately kept at 185° C. for 15 minutes, then kept at 20° C. for 336 hours, and then aged at 185° C. for 5 hours. Other processing techniques are the same as those in Example 1.

[0035] Example 5

[0036] The composition of the 6063 aluminum alloy is as follows, in percentage by mass: Mg=0.5 wt.%, Si=0.4 wt.%, Cu=0.01 wt.%, and the remaining components are Al and unavoidable impurities.

[0037] After quenching, the aluminum alloy is immediately kept at 180° C. for 60 minutes, then kept at 40° C. for 100 hours, and then subjected to aging treatment at 180° C. for 15 hours; other processing techniques are the same as those in Example 1.

[0038] Example 6

[0039] The composition of the 6063 aluminum alloy is as follows, in percentage by mass: Mg=0.5 wt.%, Si=0.4 wt.%, Cu=0.01 wt.%, and the remaining components are Al and unavoidable impurities.

[0040] After quenching, the aluminum alloy was placed at room temperature for 81 hours, then kept at 180° C. for 70 minutes, then kept at 60° C. for 116 hours, and then aged at 180° C. for 18 hours. Other processing techniques were the same as those in Example 1.

[0041] Example 7

[0042] The composition of the 6060 aluminum alloy is as follows, by mass percentage: Mg 0.4 wt.%, Si 0.5 wt.%, Cu 0.01 wt.%, and the remaining components are Al and inevitable impurities.

[0043] The processing technology is consistent with that of Example 1.

[0044] Comparative Example 1

[0045] The composition of the aluminum alloy is consistent with that of Example 1, but the following processing technology is adopted: after quenching, the aluminum alloy is immediately subjected to aging treatment at 185° C. for 12 hours.

[0046] Comparative Example 2

[0047] The composition of the aluminum alloy is consistent with that of Example 7, but the following processing technology is adopted: after quenching, the aluminum alloy is immediately subjected to aging treatment at 185° C. for 12 hours.

[0048] Comparative Example 3

[0049] The composition of the aluminum alloy is consistent with that of Example 3, but the following processing technology is adopted: after quenching, the aluminum alloy is immediately kept at 140°C for 80 minutes, then kept at 90°C for 76 hours, and then aged at 170°C for 20 hours.

[0050] According to the standard GB / T6892-2015 “Aluminum and aluminum alloy extruded profiles for general industrial use”, the performance of each aluminum alloy in Examples 1 to 7 and Comparative Examples 1 to 3 was tested. The test results are shown in Table 1.

[0051] Table 1

[0052]

[0053] The aluminum alloy materials in Examples 1 and 2 were directly subjected to aging treatment after being stored at room temperature; the aluminum alloy material in Example 6 was subjected to heat treatment and then aging treatment after being stored at room temperature; the aluminum alloy materials in Examples 3, 4, and 5 were not subjected to room temperature storage but were first subjected to heat treatment and then aging treatment.

[0054] As can be seen from the data in Table 1, the aluminum alloy material treated by the process of Example 6 has higher strength than that of Examples 3, 4, and 5, but lower plasticity. The aluminum alloy material treated by the process of Example 6 has higher strength than that of Examples 1 and 2, and similar plasticity. The aluminum alloy material treated by the process of Comparative Examples 3, 4, and 5 has similar strength properties to those of Examples 1 and 2, but higher plasticity.

[0055] As can be seen from the data in Table 1, the electrical conductivity (% IACS) of the 6063 aluminum alloy and 6060 aluminum alloy materials treated by the above three methods of the present invention is significantly better than that of the comparative example, indicating that their corrosion resistance is improved.

[0056] It can be seen from the data in Table 1 that the above-mentioned low-alloyed 6 series aluminum alloy is processed by conventional melting, casting, homogenization annealing, extrusion and solution quenching, and then treated by the treatment process of the present invention. The comprehensive performance of the 6063 aluminum alloy and 6060 aluminum alloy materials treated by the above three methods of the present invention is better than that of the comparative example aluminum alloy.

[0057] The present invention adjusts the heat treatment process to enable the low-alloyed 6 series aluminum alloy to have higher mechanical properties without slowing down the extrusion speed, thereby avoiding the degradation of processing performance and corrosion resistance caused by improving performance by adjusting the composition.

[0058] Based on the disclosure of the above description, those skilled in the art may also 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 any modifications and variations of the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although certain specific terms are used in this description, these terms are merely for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A low-alloyed 6-series aluminum alloy, characterized by: Calculated by mass percentage, comprising: Si≤0.6wt.%, Mg≤0.6wt.%, Cu≤0.2wt.%, and the remaining components being Al and unavoidable impurities; The processing method of the low-alloyed 6 series aluminum alloy is as follows: after the low-alloyed 6 series aluminum alloy is solution quenched, it is kept at room temperature for more than 48 hours, then kept at 170-185° C. for 15-80 minutes, then kept at a temperature of ≤80° C. for 76-336 hours, and then subjected to aging treatment at 170-190° C. for 5-20 hours.

2. The low-alloyed 6-series aluminum alloy according to claim 1, characterized in that: The low-alloyed 6 series aluminum alloy is 6063 aluminum alloy or 6060 aluminum alloy.

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