High-strength 6-series aluminum alloy and processing technology thereof

Abstract

The processing technology comprises the following steps: weighing 0.8 to 1.3 weight percent of Mg, 0.7 to 1.4 weight percent of Si, 0.8 to 2.2 weight percent of Cu, 0.20 to 1.2 weight percent of Mn, less than or equal to 0.5 weight percent of Fe, 0.1 to 0.5 weight percent of Cr, less than or equal to 0.05 weight percent of Ti, 0.05 to 0.35 weight percent of Ce, less than or equal to 0.5 weight percent of total mass of inevitable impurities and the balance of Al according to mass percent, and carrying out ingot casting; and the cast ingot is subjected to homogenization treatment, the homogenized material is extruded, the extruded material is subjected to aging treatment and then subjected to deformation machining treatment, and the aluminum alloy material is obtained. By adjusting the contents of elements such as Mg, Si, Cu, Mn, Cr, Ce and the like and controlling the process, the 6-series aluminum alloy material has relatively high yield strength of more than or equal to 500MPa and tensile strength of more than or equal to 520MP.

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 and a processing technology thereof. Background Art

[0002] 6 series aluminum alloys usually have good forming properties, medium strength and good corrosion resistance, so they are widely used in military and civilian products. Commonly used 6 series aluminum alloys include 6063 (yield strength ~ 200MPa), 6061 (yield strength ~ 300MPa), and 6013 (yield strength ~ 430MPa). When there is a higher strength requirement, 7 series aluminum alloys are usually used. However, the corrosion resistance and recyclability of 7 series aluminum alloys are poor, so 7 series is not the best choice. Therefore, it is necessary to develop a higher strength 6 series aluminum alloy and its processing technology to meet higher application requirements. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a high-strength 6-series aluminum alloy and a processing technology thereof, which is suitable for application fields with extremely high requirements on the strength of aluminum alloys.

[0004] The purpose of the present invention is achieved through the following technical solutions: First, the present invention provides a high-strength 6-series aluminum alloy, which includes, by mass percentage, Mg 0.8-1.3wt.%, Si 0.7-1.4wt.%, Cu 0.8-2.2wt.%, Mn 0.20-1.2wt.%, Fe ≤0.5wt.%, Cr0.1-0.5wt.%, Ti ≤0.05wt.%, Ce 0.05-0.35wt.%, the total mass of inevitable impurities ≤0.5wt.%, and the balance is Al.

[0005] Furthermore, the tensile strength of the high-strength 6 series aluminum alloy is ≥520MPa, and the yield strength is ≥500MPa.

[0006] Secondly, the present invention provides a processing technology for the above-mentioned high-strength 6 series aluminum alloy, comprising 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 is homogenized, and the temperature is raised from room temperature to 400-480°C at a heating rate of 10°C-30°C / h, and kept at that temperature for 4-8h, and then raised to 500-560°C, and kept at that temperature for 5-20h; The homogenized material is extruded, the extrusion rod temperature is 480-560°C, and the extrusion material outlet temperature is 520-550°C; Perform aging treatment on the extruded material, keeping the extruded material at 185-200°C for 2-20h; The extruded material after aging treatment is deformed, and the deformation amount is controlled within 2 to 15%.

[0007] Furthermore, the homogenized material is extruded, and the proportion of insoluble intermetallic compounds in the compressed material is greater than 8%, and the proportion of deformed grains is greater than 98%.

[0008] Furthermore, the extruded material after the aging treatment is subjected to deformation treatment, specifically comprising: passing the extruded material after the aging treatment through a stretching machine to generate a stretching deformation of 2 to 15%.

[0009] In 6 series aluminum alloys, Mg, Si, and Cu are the main additive elements. Their content levels determine the mechanical properties of the material. The greater the amount added, the higher the strength. However, if the content exceeds the solid solubility limit of the material, a large amount of insoluble phases will be formed in the structure, which will not help improve the mechanical properties and will cause a decrease in toughness. Therefore, the content is controlled to be Mg0.8~1.3 wt.%, Si 0.7~1.4wt.%. Cu plays a strengthening role. In the case of a higher content, it is beneficial to improve the work hardening ability of the material.

[0010] Mn and Cr are trace elements added mainly to control the grain size. When the material contains 0.20-1.2wt.% Mn and 0.1-0.5wt.% Cr, a large amount of insoluble phases will form in the structure, which will promote the formation of deformed fiber grains, bring deformation strengthening / texture strengthening, and further improve the performance of the material on the basis of aging strengthening. Ce is a rare earth element, and its addition purpose is to further strengthen the control of Mn and Cr on the grain structure. Its content is preferably 0.05-0.35wt.%.

[0011] Ti is a trace element mainly used to control the as-cast grains. As long as the as-cast grains are within the required range, its content can be ≤0.05wt.%.

[0012] Fe is an impurity element, and its content is preferably Fe≤0.5wt.%.

[0013] The ingots of the above composition are homogenized, and the temperature is increased from room temperature to 400-480℃ at a heating rate of 10℃-30℃ / h, and kept for 4-8h, and then increased to 500-560℃, and kept for 5-20h. The heating rate of homogenization and the heat preservation at 400-480℃ are controlled to promote the precipitation of Mn and Cr phases. The temperature at 500-560℃ and the heat preservation for 5-20h are to promote the dissolution of the soluble phase; the extrusion rod temperature is 480-560℃, and the outlet temperature of the homogenized rod in the barrel is 520-550℃, in order to form the product and provide a tissue basis for subsequent aging precipitation; the aging system is adopted, and the temperature is kept at 185-200℃ for 2-20h, in order to carry out aging strengthening and improve the strength of the material; the aged material is deformed and 2-15% deformation is applied, in order to further improve the performance of the material through dislocation strengthening.

[0014] The present invention enables the material to obtain ultra-high strength by adjusting the content of elements such as Mg, Si, Cu, Mn, Cr, Ce and the like and controlling the process, and is suitable for fields requiring high material strength. 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 composition of the 6 series aluminum alloy is calculated by mass percentage as follows: Mg 0.8wt.%, Si 1.4wt.%, Mn 1.2wt.%, Cr0.5wt.%, Cu 2.2wt.%, Ti 0.05wt.%, Fe 0.5wt.%, Ce 0.05wt.%, inevitable impurities ≤0.5wt%, and the balance is Al; 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 of the above composition is homogenized, heated from room temperature to 480°C at a heating rate of 10°C / h and kept at that temperature for 4h, then heated to 500°C and kept at that temperature for 20h; The homogenized material is extruded, the extrusion rod temperature is 560℃, the homogenized rod extrusion material outlet temperature is 550℃, and the extrusion speed is 10m / min; The extruded material was subjected to aging treatment at 185°C for 20 hours; The extruded material after aging treatment is further deformed by applying 2% deformation through a stretching machine.

[0017] Example 2 The composition of 6 series aluminum alloy is calculated by mass percentage: Mg 1.3wt.%, Si 0.7wt.%, Mn 0.2wt.%, Cr0.1wt.%, Cu 0.8wt.%, Ti 0.03wt.%, Fe 0.15wt.%, Ce 0.35 wt.%, inevitable impurities ≤ 0.5wt%, and the balance is Al; 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, heated from room temperature to 400°C at a heating rate of 30°C / h and kept at that temperature for 8h, then heated to 560°C and kept at that temperature for 5h; The homogenized material is extruded, the extrusion rod temperature is 480℃, the homogenization rod extrusion material outlet temperature is 520℃, and the extrusion speed is 10m / min; The extruded material was subjected to aging treatment at 200°C for 2h; The extruded material after aging treatment is further deformed by applying 15% deformation through a stretching machine.

[0018] Example 3 The composition of the 6 series aluminum alloy is calculated by mass percentage as follows: Mg 1.0wt.%, Si 1.1wt.%, Mn 0.8wt.%, Cr0.4wt.%, Cu 1.1wt.%, Ti 0.02wt.%, Fe 0.35wt.%, Ce 0.15wt.%, inevitable impurities ≤0.5wt%, and the balance is Al; 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 was homogenized, heated from room temperature to 460°C at a heating rate of 15°C / h and kept at that temperature for 6h, then heated to 520°C and kept at that temperature for 15h; The homogenized material is extruded, the extrusion rod temperature is 510℃, the homogenization rod extrusion material outlet temperature is 530℃, and the extrusion speed is 10m / min; The extruded material was subjected to aging treatment at 190°C for 4 hours; The extruded material after aging treatment is further deformed by applying 12% deformation through a stretching machine.

[0019] Comparative Example 1 The composition of 6 series aluminum alloy is calculated by mass percentage: Mg 0.8wt.%, Si 1.4wt.%, Mn 0.01wt.%, Cr0.01wt.%, Cu 2.2wt.%, Ti 0.05wt.%, Fe 0.11wt.%, Ce 0.001wt.%, inevitable impurities ≤0.5wt%, and the balance is Al; The processing technology of the aluminum alloy in Comparative Example 1 is consistent with that in Example 1.

[0020] Comparative Example 2 The composition of the aluminum alloy in Comparative Example 2 is consistent with that in Example 1, except that: The ingots of the above composition are homogenized and kept at 420°C for 20 hours; The homogenized material is extruded, the extrusion rod temperature is 480℃, and the extrusion material outlet temperature is 500℃; The extruded material was subjected to aging treatment at 185°C for 20 hours.

[0021] Comparative Example 3 The composition of 6 series aluminum alloy is as follows by mass percentage: Mg 0.8wt.%, Si 1.4wt.%, Mn 0.01wt.%, Cr0.01wt.%, Cu 2.2wt.%, Ti 0.05wt%, Fe 0.11wt.%, Ce 0.4wt.%, inevitable impurities ≤0.5wt%, and the balance is Al; The processing technology of the aluminum alloy in Comparative Example 3 is consistent with that in Example 1.

[0022] Comparative Example 4 The composition of the aluminum alloy in Comparative Example 4 is consistent with that in Example 1, except that: The extruded material after aging treatment is further deformed by applying 20% ​​deformation through a stretching machine.

[0023] 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 4 was tested. Table 1 shows the performance and microstructure characteristics of the aluminum alloy in Examples 1-3 and Comparative Examples 1-4.

[0024] Table 1

[0025] The present invention reasonably adjusts the content of each element in the aluminum alloy and the processing technology so that the material has higher strength and is suitable for the demand for extremely high strength.

[0026] 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 high-strength 6-series aluminum alloy, characterized in that: Calculated by mass percentage, it includes: Mg 0.8-1.3wt.%, Si 0.7-1.4wt.%, Cu 0.8-2.2wt.%, Mn 0.20-1.2wt.%, Fe≤0.5wt.%, Cr 0.1-0.5wt.%, Ti≤0.05wt.%, Ce 0.05-0.35wt.%, the total mass of unavoidable impurities ≤0.5wt.%, and the balance is Al.

2. The high-strength 6-series aluminum alloy according to claim 1, characterized in that: The tensile strength of the high-strength 6 series aluminum alloy is ≥520MPa, and the yield strength is ≥500MPa.

3. A processing technology for high-strength 6-series aluminum alloy according to claim 1 or 2, 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 is homogenized, first at 400-480°C for 4-8 hours, then at 500-560°C for 5-20 hours; The homogenized material is extruded, the extrusion rod temperature is 480-560°C, and the extrusion material outlet temperature is 520-550°C; Aging treatment of extruded materials; The extruded material after aging treatment is deformed, and the deformation amount is controlled within 2 to 15%.

4. The processing technology of high-strength 6-series aluminum alloy according to claim 3 is characterized in that: The homogenized material is extruded, and the proportion of insoluble intermetallic compounds in the compressed material is greater than 8%, and the proportion of deformed grains is greater than 98%.

5. The processing technology of high-strength 6-series aluminum alloy according to claim 3 is characterized in that: The ingot is homogenized, heated from room temperature to 400-480°C at a heating rate of 10°C-30°C / h, kept warm for 4-8h, then heated to 500-560°C, and kept warm for 5-20h.

6. The processing technology of high-strength 6-series aluminum alloy according to claim 3 is characterized in that: The extruded material is subjected to aging treatment by keeping the extruded material at 185-200°C for 2-20 hours.

7. The processing technology of high-strength 6-series aluminum alloy according to claim 3 is characterized in that: The extruded material after aging treatment is subjected to deformation treatment, specifically comprising: passing the extruded material after aging treatment through a stretching machine to generate a stretching deformation of 2 to 15%.

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