High-rigidity aluminum alloy round cast ingot and preparation method thereof

Abstract

The invention discloses a high-rigidity aluminum alloy round cast ingot and a preparation method thereof, and belongs to the technical field of aluminum alloys. The high-rigidity aluminum alloy round cast ingot provided by the invention comprises the following components in percentage by weight: 2.4-2.8% of Mg, 0.1% of Si, 0.15% of Fe, 0.6-1.2% of Cu, less than or equal to 0.02% of Ti, 0.002% of B, 5.8-7.2% of Zn, 0.09-0.2% of Mn, less than or equal to 0.02% of Cr, less than or equal to 0.02% of Zr, 0.02% of Sr and the balance of Al. By strictly controlling the content of Mg / Zn, reasonably configuring the content of Cu and Mn, controlling the added content of Cr and cooperating with a reasonable preparation process, the mechanical property of the material can be remarkably improved, and meanwhile, the glossiness of the material subjected to high-brightness anodic oxidation is controlled.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloys, and in particular relates to a high-rigidity aluminum alloy round ingot and a preparation method thereof. Background Art

[0002] Due to its light weight and high strength, 7 series aluminum alloys are widely used in aerospace, automobile manufacturing, outdoor construction, sports equipment and other fields. For example, the Chinese invention patent with application number 202310565591.6 discloses an ultra-high strength and corrosion-resistant 7 series Al-Zn-Mg-Cu aluminum alloy, including the following mass percentage components: Zn 9.00-10.00wt.%, Mg 2.00-3.20wt.%, Cu 1.00-3.00wt.%, Zr 0.13-0.30wt.%, Ti0.05-0.15wt.%, Fe 0.01-0.10wt.% and Si 0.001-0.10wt.%, and the balance is Al. The aluminum alloy increases the content of Zn and Mg and reduces the content of Cu through the synergistic effect between the constituent elements, greatly improving the mechanical strength of the material. After testing, the tensile strength of the alloy material can reach up to 750MPa and the yield strength can reach up to 700MPa. However, with the continuous development of industry and the continuous refinement of application fields, the environment in which materials are used is becoming more and more complex and demanding, and the performance requirements for 7 series aluminum alloys are becoming higher and higher and more diverse. At the same time, there is also the problem that only the mechanical properties are improved but the glossiness is not enough, and the high-gloss anode appearance effect cannot be achieved. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a high-rigidity aluminum alloy round ingot with a tensile strength of ≥580MPa, a yield strength of ≥560MPa, an elongation of ≥10%, a Vickers hardness HV ≥200 and a high-brightness anode effect, and a preparation method thereof.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a high-rigidity aluminum alloy round ingot, calculated by weight percentage, comprises: 2.4~2.8% Mg, 0.1% Si, 0.15% Fe, 0.6~1.2% Cu, ≤0.02% Ti, 0.002% B, 5.8~7.2%Zn, 0.09~0.2% Mn, ≤0.02% Cr, ≤0.02% Zr, 0.02% Sr and balance Al.

[0005] The beneficial effects of the present invention are as follows: by strictly controlling the Mg / Zn content, rationally configuring the Cu and Mn contents, controlling the content of Cr addition, and coordinating a reasonable heat treatment process, the mechanical properties of the material can be significantly improved, and at the same time, the glossiness of the material after high-brightness anodizing can be controlled to reach 420~600GU (oxide film thickness 12~15μm). DETAILED DESCRIPTION

[0006] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes.

[0007] High rigidity aluminum alloy round ingot, comprising, by weight percentage, 2.4~2.8% Mg, 0.1% Si, 0.15% Fe, 0.6~1.2% Cu, ≤0.02% Ti, 0.002% B, 5.8~7.2% Zn, 0.09~0.2% Mn, ≤0.02% Cr, ≤0.02% Zr, 0.02% Sr and balance Al.

[0008] Among them, the ratio of Mg to Zn is 2.1~2.8.

[0009] From the above description, it can be seen that the beneficial effects of the present invention are: by controlling the Mg / Zn content to keep it at 2.1~2.8, rationally configuring the Cu and Mn contents to be 0.6~1.2% and 0.09~0.2% Mn respectively, and controlling the Cr addition content to be 0.02% or less, it plays a role in increasing the corrosion resistance of the material and controlling the grain size, and cooperates with reasonable solid solution process and aging process to improve the mechanical properties of the material, so that it can achieve tensile strength ≥580MPa, yield strength ≥560MPa, elongation ≥10%, Vickers hardness HV ≥200, and at the same time ensure that the subsequent materials meet the requirements of sandblasting and high-brightness anodizing, presenting a bright effect, and the glossiness reaches 420-600GU when the oxide film thickness is 12-15μm. Overcome the problem that some 7 series aluminum alloys only have improved mechanical properties but insufficient glossiness, and cannot achieve the appearance effect of a bright anode.

[0010] Among them, the content of Cr added should not be too high, otherwise it will affect the improvement of mechanical properties.

[0011] Among them, the Ti addition content is generally controlled at 0.01~0.02%.

[0012] Furthermore, the above-mentioned high-rigidity aluminum alloy round ingot also includes impurity elements, and the content of a single impurity element is ≤0.05%. The total content of all impurity elements is ≤0.1%. The presence of a certain amount of single or multiple impurities will not significantly affect the physical properties of the aluminum alloy round ingot.

[0013] Furthermore, the above-mentioned high-rigidity aluminum alloy round ingot also includes impurity elements with a tensile strength of ≥580MPa, a yield strength of ≥560MPa, an elongation of ≥10%, and a Vickers hardness HV ≥200.

[0014] From the above description, it can be seen that by adjusting and controlling the content of each element, the tensile strength, yield strength and Vickers hardness of the obtained aluminum alloy round ingot can be significantly improved, making it have the characteristics of high rigidity.

[0015] The method for preparing the high-rigidity aluminum alloy round ingot specifically comprises the following steps: S1. Raw material smelting: Put the required raw materials into a furnace in proportion and smelt at 740-750° C. for 4-6 hours to obtain an aluminum alloy melt, wherein the quality of the raw materials meets the following requirements: 2.4-2.8% Mg, 0.1% Si, 0.15% Fe, 0.6-1.2% Cu, ≤0.02% Ti, 0.002% B, 5.8-7.2% Zn, 0.09-0.2% Mn, ≤0.02% Cr, ≤0.02% Zr, 0.02% Sr and the balance Al; S2. Aluminum alloy melt composition analysis: Use ICP-OES or XRF to analyze the composition of the aluminum alloy melt to determine its components; S3. Alloying treatment: According to the analysis results of the aluminum alloy melt composition, a proper amount of alloying elements is added to the aluminum alloy melt at 730-745°C by adding solid alloy to perform alloying treatment; S4, Refining and Slagging: After alloying treatment, a high-efficiency refining agent is added to the aluminum alloy melt, wherein the high-efficiency refining agent includes one or more of magnesium chloride, potassium chloride, and calcium fluoride, and is used to remove impurities and bubbles in the melt; S5, Casting: The aluminum alloy melt after refined slag treatment is poured into the casting mold for casting. The casting temperature is 690~715℃ and the pouring speed is 0.6~1.4m / min. S6, cooling and solidification: After the aluminum alloy melt is cooled and solidified, an aluminum alloy rod with a diameter of 127-305 mm is obtained. The cooling and solidification time is 1-3 hours, and the cooling temperature is room temperature. S7, precision cutting: Precision cutting the cooled and solidified aluminum alloy rod to obtain the required aluminum alloy ingot; S8, solution treatment: The aluminum alloy ingot is subjected to continuous heat preservation and solution treatment at 500-552°C for 15-28h; S9, aging treatment: After solution treatment, artificial aging is carried out at 150°C for 15 to 30 hours.

[0016] From the above description, it can be seen that by adopting a solution treatment at a higher temperature of more than 500°C and an artificial aging for a longer time of more than 15h, an aluminum alloy round ingot that meets both high mechanical properties and high brightness effects can be obtained.

[0017] Embodiment 1 of the present invention is: High rigidity aluminum alloy round ingot, comprising, by weight percentage, 2.5% Mg, 0.1% Si, 0.15% Fe, 0.6% Cu, 0.01% Ti, 0.002% B, 6.35% Zn, 0.13% Mn, 0.017% Cr, 0.02% Zr, 0.02% Sr and balance Al.

[0018] Embodiment 2 of the present invention is: High rigidity aluminum alloy round ingot, comprising, by weight percentage, 2.4% Mg, 0.1% Si, 0.15% Fe, 1.2% Cu, 0.02% Ti, 0.002% B, 5.8% Zn, 0.2% Mn, 0.02% Cr, 0.02% Zr, 0.02% Sr and balance Al.

[0019] Embodiment 3 of the present invention is: High rigidity aluminum alloy round ingot, comprising, by weight percentage, 2.8% Mg, 0.1% Si, 0.15% Fe, 0.75% Cu, 0.015% Ti, 0.002% B, 7.2% Zn, 0.16% Mn, 0.019% Cr, 0.02% Zr, 0.02% Sr and balance Al.

[0020] Embodiment 4 of the present invention is: High rigidity aluminum alloy round ingot, comprising, by weight percentage, 2.7% Mg, 0.1% Si, 0.15% Fe, 0.75% Cu, 0.015% Ti, 0.002% B, 7.2% Zn, 0.09% Mn, 0.019% Cr, 0.02% Zr, 0.02% Sr and balance Al.

[0021] Embodiment 5 of the present invention is: The method for preparing a high-rigidity aluminum alloy round ingot specifically comprises the following steps: S1. Raw material smelting: Put the required raw materials into a furnace in proportion and smelt at 740-750°C for 4-6 hours to obtain an aluminum alloy melt, wherein the quality of the raw materials meets the following requirements: 2.5% Mg, 0.1% Si, 0.15% Fe, 0.6% Cu, 0.01% Ti, 0.002% B, 6.35% Zn, 0.13% Mn, 0.017% Cr, 0.02% Zr, 0.02% Sr and the balance Al; S2. Aluminum alloy melt composition analysis: XRF is used to analyze the composition of aluminum alloy melt to determine its components; S3. Alloying treatment: According to the analysis results of the aluminum alloy melt composition, a proper amount of alloying elements is added to the aluminum alloy melt at 740°C by adding solid alloy to perform alloying treatment; S4, Refining and Slagging: After alloying treatment, a high-efficiency refining agent is added to the aluminum alloy melt, and the high-efficiency refining agent includes magnesium chloride, potassium chloride and calcium fluoride; S5, Casting: The aluminum alloy melt after refined slag treatment is poured into the casting mold for casting, the casting temperature is between 710℃ and the pouring speed is 1.2m / min; S6, cooling and solidification: After the aluminum alloy melt is cooled and solidified, an aluminum alloy rod with a diameter of 300 mm is obtained. The cooling and solidification time should be controlled within 3 hours, and the cooling temperature is room temperature; S7, precision cutting: The aluminum alloy rods after cooling and solidification are precisely cut to obtain aluminum alloy ingots that meet the specification requirements; S8, solution treatment: The aluminum alloy ingot was subjected to a continuous solution treatment at 530°C for 20 h; S9, aging treatment: After solution treatment, artificial aging is performed at 150°C for 20 h; After cooling at room temperature, a high-rigidity aluminum alloy round ingot is obtained.

[0022] Comparative Example 1: The only difference between Comparative Example 1 and Example 5 is that the temperature of the solution treatment is 480°C.

[0023] Comparative Example 2: The only difference between Comparative Example 2 and Example 5 is that the aging treatment time is 10 h.

[0024] The aluminum alloy round ingots obtained in Example 5, Comparative Example 1 and Comparative Example 2 were subjected to high brightness anodization and then to performance testing. The results are shown in Table 1.

[0025] Table 1

[0026] In summary, the present invention can prepare aluminum alloy round ingots with good mechanical properties and high gloss by adjusting the component content and improving the solid solution treatment process and the aging process.

[0027] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. High rigidity aluminum alloy round ingot, characterized in that: In terms of weight percentage, it includes: 2.4~2.8% Mg, 0.1% Si, 0.15% Fe, 0.6~1.2% Cu, ≤0.02% Ti, 0.002% B, 5.8~7.2% Zn, 0.09~0.2% Mn, ≤0.02% Cr, ≤0.02% Zr, 0.02% Sr and balance Al.

2. The high rigidity aluminum alloy round ingot according to claim 1, characterized in that: It also includes impurity elements, and the content of a single impurity element is ≤0.05%.

3. The high rigidity aluminum alloy round ingot according to claim 2, characterized in that: The total content of all impurity elements is ≤0.1%.

4. The high rigidity aluminum alloy round ingot according to claim 1, characterized in that: The high-rigidity aluminum alloy round ingot has a tensile strength of ≥580 MPa, a yield strength of ≥560 MPa, an elongation of ≥10%, and a Vickers hardness HV of ≥200.

5. The method for preparing a high-rigidity aluminum alloy round ingot according to any one of claims 1 to 4, characterized in that: The following steps are involved: Raw material smelting, aluminum alloy melt composition analysis, alloying treatment, refining and slag removal, casting and molding, cooling and solidification, precision cutting, solution treatment and aging treatment.

6. The preparation method according to claim 5, characterized in that: The raw material smelting is carried out at a temperature of 740-750°C.

7. The preparation method according to claim 5, characterized in that: The alloying treatment is performed at a temperature of 730-745°C.

8. The preparation method according to claim 5, characterized in that: The casting is carried out at a temperature of 690-715°C.

9. The preparation method according to claim 5, characterized in that: The solution treatment is carried out at 500-552° C. for 15-28 hours.

10. The preparation method according to claim 5, characterized in that: The aging treatment is artificial aging at 150° C. for 15 to 30 hours.

Images