6-series aluminum alloy capable of being extruded at high speed and processing technology of 6-series aluminum alloy

Abstract

The invention relates to the technical field of aluminum alloys, in particular to a 6-series aluminum alloy capable of being extruded at a high speed and a processing technology thereof, and the aluminum alloy comprises the following components in percentage by mass: 0.45-0.6 wt.% of Mg, 0.45-0.8 wt.% of Si, 0.01-0.05 wt.% of Cu, 0.01-0.05 wt.% of Mn, less than or equal to 0.2 wt.% of Fe, less than or equal to 0.05 wt.% of Cr, less than or equal to 0.05 wt.% of Ti, less than or equal to 0.5 wt.% of inevitable impurities, and the balance of Al. By reasonably adjusting the content of each element in the aluminum alloy and carrying out homogenization treatment, high-speed extrusion and aging treatment on the aluminum alloy ingot containing the components, the 6-series aluminum alloy material has higher strength and is suitable for large-scale rapid production of 6-series aluminum and the field of aluminum processing with higher requirements on cost and efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloys, and in particular to a 6-series aluminum alloy capable of high-speed extrusion and a processing technology thereof. Background Art

[0002] 6 series aluminum alloys are widely used in the manufacture of various parts for civilian products due to their good mechanical properties, processing properties and anode appearance. 6063 aluminum alloy is one of the most widely used alloys among the 6 series aluminum alloys. Due to the low alloying, the alloy has low mechanical properties and good processability. Usually the extrusion speed of the alloy is 15 meters per minute, and the typical yield strength is 200MPa. If you want to increase the extrusion speed of the material, both to improve the production efficiency of the material and reduce the cost, the most direct way is to reduce the alloying level, but the strength will decrease accordingly. Therefore, it is necessary to develop a 6 series aluminum alloy that can be extruded at high speed and its processing technology to meet the needs of industrial development. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a 6 series aluminum alloy capable of high-speed extrusion and a processing technology thereof, which can maintain the strength of the aluminum alloy and improve production efficiency, and meet the needs of industrial development.

[0004] The purpose of the present invention is achieved through the following technical solutions: First, the present invention provides a 6 series aluminum alloy that can be extruded at high speed, which includes the following raw material components, calculated by mass percentage: Mg 0.45-0.6wt.%, Si 0.45-0.8wt.%, Cu 0.01-0.05wt.%, Mn 0.01-0.05wt.%, Fe ≤0.2wt.%, Cr ≤0.05wt.%, Ti ≤0.05wt.%, the total mass of inevitable impurities ≤0.5wt.%, and the balance is Al. Furthermore, the content ratio of Si to Mg in the raw material components of the high-speed extrudable 6-series aluminum alloy is greater than 1.

[0005] Furthermore, the mass percentages of Si and Mg in the raw material components of the high-speed extrudable 6-series aluminum alloy meet the following condition: Si≥1.1Mg+0.05wt.%.

[0006] Furthermore, the tensile strength of the high-speed extruded 6 series aluminum alloy is >280MPa, and the yield strength is >260MPa.

[0007] Secondly, the present invention provides a processing technology for high-speed extrusion of the 6-series aluminum alloy, which comprises the following steps: Weigh raw materials according to the mass percentage of each element in the aluminum alloy, and perform smelting and casting to obtain an ingot; The ingot with the above composition is homogenized, kept at 540-580°C for 4-16 hours, then cooled to 380-460°C at a rate of 15-30°C / h, and then cooled to room temperature at a rate of 60-100°C / h; The homogenized material is extruded at a speed of 23-28 m / min, an extrusion rod temperature of 480-560°C, and an outlet temperature of 520-550°C; The extruded material was subjected to aging treatment at 175°C for 9 hours.

[0008] Furthermore, after homogenization, the size of Mg2Si in the material is ≤3 microns.

[0009] In 6 series aluminum alloys, Mg, Si, and Cu are the main added elements. Their content levels determine the mechanical properties of the material. The greater the amount added, the higher the strength. However, if the content is too high, the deformation resistance of the material will increase and the deformation speed will decrease. When the Si content is greater than the Mg content, the deformation speed of the material will increase. However, if the Si content is too high, the mechanical properties will decrease and the deformation speed will decrease. In general: Mg 0.45~0.6wt.%, Si 0.45~0.8wt.%, and Si≥1.1Mg+0.05wt.% are conducive to increasing the extrusion speed and maintaining high mechanical properties of the material. The addition of trace Cu is conducive to improving the work hardening ability, that is, under a certain deformation amount, the Cu-containing alloy is more conducive to improving the mechanical properties after deformation. However, if the Cu content is added too much, the corrosion resistance will decrease. Therefore, the Cu content is preferably 0.01~0.05wt.%.

[0010] The presence of Mn element mainly promotes the transformation of Fe-containing phase from needle-shaped to granular, which is beneficial to the improvement of extrusion speed and extrusion surface quality. Its content is preferably 0.01-0.05wt.%, and too high will also cause the extrusion speed to decrease. Ti is a grain refiner, and its content Ti ≤0.05wt.% is sufficient.

[0011] Other elements Fe and Cr are impurity elements, and their contents may be controlled within the range of Fe ≤ 0.2wt.% and Cr ≤ 0.05wt.%.

[0012] The ingot with the above composition is homogenized, kept at 540-580℃ for 4-16h, then cooled to 380-460℃ at a rate of 15℃ / h-30℃ / h, and then cooled to room temperature at a rate of 60℃ / h-100℃ / h. Keeping at 540-580℃ for 4-16h is to soften the material to eliminate internal stress and dissolve the coarse Mg2Si phase; after the insulation, cool it to 380-460℃ at a rate of 15℃ / h-30℃ / h. The cooling rate is controlled to promote the precipitation of fine Mg2Si from Mg and Si elements in the matrix, reduce the hardness of the material, and facilitate subsequent extrusion. In this process, the cooling rate and final temperature must be controlled to make the precipitated Mg2Si of moderate size. If its size is too large, it will easily melt during the subsequent extrusion heating process, resulting in structural defects, appearance defects and a decrease in extrusion speed. If the size is too small, the softening effect will be poor, which is not conducive to increasing the extrusion speed. After this stage, the temperature is lowered to room temperature at a rate of 60℃ / h to 100℃ / h in order to improve production efficiency and avoid further coarsening of the Mg2Si phase.

[0013] The homogenized material is extruded, with the extrusion rod temperature at 480-560°C and the outlet temperature at 520-550°C. The purpose of controlling the extrusion rod temperature and the outlet temperature is to promote the forming process and dissolve the fine Mg2Si in the homogenization process to provide a tissue basis for subsequent aging strengthening. The extruded material is subjected to aging treatment: 175°C for 9 hours to improve the mechanical properties of the material.

[0014] The present invention adjusts the content of each element in the 6-series aluminum alloy and controls the process so that the material can obtain higher extrusion production efficiency. It is suitable for large-scale rapid production of 6-series aluminum and aluminum processing fields with high requirements on cost and efficiency. DETAILED DESCRIPTION

[0015] 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.

[0016] Example 1 The 6 series aluminum alloy includes, by mass percentage, Mg 0.45wt.%, Si 0.56wt.%, Cu 0.01wt.%, Mn0.05wt.%, Fe 0.2wt.%, Cr 0.05wt.%, Ti 0.05wt.%, the total mass of inevitable impurities ≤0.5wt.%, and the balance is Al.

[0017] The ingot with the above composition was homogenized, kept at 540°C for 16 h, then cooled to 460°C at a rate of 15°C / h, and then cooled to room temperature at a rate of 100°C / h.

[0018] The homogenized material was extruded at an extrusion speed of 28 m / min, an extrusion rod temperature of 480°C, and an outlet temperature of 550°C.

[0019] Aging treatment of extruded materials: 175℃ for 9h.

[0020] Example 2 The 6 series aluminum alloy includes, by mass percentage, Mg 0.51wt.%, Si 0.68wt.%, Cu 0.05wt.%, Mn0.01wt.%, Fe 0.1wt.%, Cr 0.03wt.%, Ti 0.02wt.%, the total mass of inevitable impurities ≤0.5wt.%, and the balance is Al.

[0021] The ingot with the above composition was homogenized, kept at 580°C for 4 hours, then cooled to 380°C at a rate of 30°C / h, and then cooled to room temperature at a rate of 60°C / h.

[0022] The homogenized material was extruded at an extrusion speed of 23 m / min, an extrusion rod temperature of 560°C, and an outlet temperature of 520°C.

[0023] Aging treatment of extruded materials: 175℃ for 9h.

[0024] Example 3 The 6 series aluminum alloy includes, by mass percentage, Mg 0.6wt.%, Si 0.75wt.%, Cu 0.03wt.%, Mn0.02wt.%, Fe 0.12wt.%, Cr 0.01wt.%, Ti 0.01wt.%, the total mass of inevitable impurities ≤0.5wt.%, and the balance is Al.

[0025] The ingot with the above composition was homogenized, kept at 560°C for 10 h, then cooled to 440°C at a rate of 18°C / h, and then cooled to room temperature at a rate of 80°C / h.

[0026] The homogenized material was extruded at an extrusion speed of 25 m / min, an extrusion rod temperature of 520°C, and an outlet temperature of 530°C.

[0027] Aging treatment of extruded materials: 175℃ for 9h.

[0028] Comparative Example 1 The aluminum alloy includes, by mass percentage, Mg 0.56wt.%, Si 0.45wt.%, Cu 0.01wt.%, Mn 0.05wt.%, Fe 0.2wt.%, Cr 0.05wt.%, Ti 0.05wt.%, the total mass of inevitable impurities ≤0.5wt.%, and the balance is Al.

[0029] The ingot with the above composition was homogenized, kept at 540°C for 16 h, then cooled to 460°C at a rate of 15°C / h, and then cooled to room temperature at a rate of 100°C / h.

[0030] The homogenized material was extruded at an extrusion speed of 19 m / min, an extrusion rod temperature of 480°C, and an outlet temperature of 550°C.

[0031] Aging treatment of extruded materials: 175℃ for 9h.

[0032] Comparative Example 2 The composition of the aluminum alloy in Comparative Example 2 is consistent with that in Example 1, except that: The ingot with the above composition was homogenized, kept at 540°C for 16 h, and then cooled to room temperature at a rate of 100°C / h.

[0033] The homogenized material was extruded at an extrusion speed of 17 m / min, an extrusion rod temperature of 480°C, and an outlet temperature of 550°C.

[0034] Aging treatment of extruded materials: 175℃ for 9h.

[0035] According to the standard GB / T6892-2015 "General Industrial Aluminum and Aluminum Alloy Extrusion Profiles", the performance of each aluminum alloy in Examples 1 to 3 and Comparative Examples 1 to 2 was tested. Table 1 shows the performance and microstructure characteristics of the aluminum alloy in Examples 1-3 and Comparative Examples 1-2.

[0036] Table 1

[0037] The present invention reasonably adjusts the content of each element in the aluminum alloy and the processing technology so that the material has a higher extrusion speed and strength, and is suitable for large-scale rapid production of 6 series aluminum and aluminum processing fields with high requirements on cost and efficiency.

[0038] According to the disclosure of the above description, those skilled in the art to which the present invention belongs 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 some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A 6 series aluminum alloy capable of high-speed extrusion, characterized in that: Calculated by mass percentage, the raw material components include: Mg 0.45-0.6wt.%, Si 0.45-0.8wt.%, Cu 0.01-0.05wt.%, Mn 0.01-0.05wt.%, Fe ≤0.2wt.%, Cr ≤0.05wt.%, Ti ≤0.05wt.%, the total mass of inevitable impurities ≤0.5wt.%, and the balance is Al.

2. The high-speed extrudable 6-series aluminum alloy according to claim 1, characterized in that: The content ratio of Si to Mg in the raw material components of the high-speed extrudable 6-series aluminum alloy is greater than 1.

3. The high-speed extrudable 6-series aluminum alloy according to claim 2, characterized in that: The mass percentages of Si and Mg in the raw material components of the high-speed extrudable 6-series aluminum alloy meet the following condition: Si≥1.1Mg+0.05wt.%.

4. The high-speed extrudable 6-series aluminum alloy according to claim 1, characterized in that: The tensile strength of the high-speed extrudable 6 series aluminum alloy is >280MPa, and the yield strength is >260MPa.

5. A processing technology for high-speed extrusion of 6 series aluminum alloy according to any one of claims 1 to 4, characterized in that: The steps include: Weigh raw materials according to the mass percentage of each element in the aluminum alloy, and perform smelting and casting to obtain an ingot; The ingot with the above composition is homogenized, kept at 540-580°C for 4-16 hours, then cooled to 380-460°C at a rate of 15-30°C / h, and then cooled to room temperature at a rate of 60-100°C / h; The homogenized material is extruded at a speed of 23-28 m / min, an extrusion rod temperature of 480-560°C, and an outlet temperature of 520-550°C; The extruded material was subjected to aging treatment at 175°C for 9 hours.

6. The high-speed extrusion process of 6 series aluminum alloy according to claim 5 is characterized in that: After homogenization, the size of Mg2Si in the material is ≤3 microns.

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