Anodic oxidation die-casting aluminum alloy and preparation method thereof

Abstract

The invention provides an anodic oxidation die-casting aluminum alloy and a preparation method thereof. The anodic oxidation die-casting aluminum alloy comprises the following elements of, by mass, 0.01%-1% of Mg element, 0.01%-2% of Zn element, 0.01%-2% of Si element, 0.01%-1% of Ni element, 0.2%-0.5% of Fe element, 1.6%-2.4% of Mn element, 0.1%-0.2% of Cu element, 0.02%-0.2% of Ti element, the total content of inevitable impurities smaller than or equal to 0.2%, and the balance Al element. Wherein the sum of the mass content of the Mg element and the mass content of the Zn element is 1-3%, the sum of the mass content of the Si element and the mass content of the Ni element is 0.1-2.5%, and the sum of the Fe element, the Si element and the Ni element is 0.1-3%. The aluminum alloy can be better used for producing thin-wall piece products with the thickness of 0.8-1.8 mm.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to an anodized die-casting aluminum alloy and a preparation method thereof. Background Art

[0002] Anodizing is a process that covers the surface of aluminum alloy with a colored oxide film and improves its surface aesthetics. This process is generally used for 5xxx, 6xxx and 7xxx aluminum alloy sheets. As people's requirements for the aesthetics of daily necessities continue to increase, more aluminum alloy products also have the need for anodized surface treatment. However, for some products with complex structures, aluminum alloy sheets require long-term CNC processing, which greatly increases costs. The anodized die-cast alloy obtained by the die-casting process can meet this demand.

[0003] However, most of the current anodized die-casting alloys are Al-Mn alloys. Due to the small amount of Si added or even no Si added, the fluidity of the anodized die-casting alloy is low, especially for thin-walled parts with a wall thickness of less than 1.5 mm in die-casting products. When the structure of the die-casting product is more complex, the thin wall thickness of the thin-walled parts and the fast cooling rate make the die-casting product not only difficult to fully form, but also prone to defects such as lack of meat and delamination, which seriously affects the yield of the die-casting product.

[0004] The Chinese patent application with patent application number CN202310889062.1 provides an anodized die-casting alloy, which improves the fluidity of the alloy by adding 1.5 to 3.0% Si element. However, this method not only easily makes the surface of the alloy dark after anodization, but also part of the Al-Si eutectic phase will be exposed in the surface layer of the die-casting. After anodization, black spot defects are likely to appear near this position, resulting in reduced surface quality and yield of the die-casting, and significantly reduced surface white brightness of the die-casting, thereby affecting the aesthetics of the die-casting.

[0005] In addition, in anodized die-casting alloys, the amount of Fe added is usually small, mainly to reduce the effect of Fe on the continuity of the oxide film. However, too little Fe addition will affect the demoulding of die-casting parts, especially thin-walled products are prone to deformation during demoulding, and even make the alloy product scrapped, resulting in a sharp increase in the production cost of thin-walled products. Summary of the invention

[0006] The main purpose of the present invention is to provide an anodized die-cast aluminum alloy and a preparation method thereof, so as to solve the problems in the prior art that anodized die-cast aluminum alloy is difficult to form when preparing thin-walled products with relatively thin thickness, is easy to deform during demolding, and has low surface quality and yield rate of anodized die-cast aluminum alloy.

[0007] In order to achieve the above object, according to one aspect of the present invention, there is provided an anodized die-casting aluminum alloy, which comprises the following elements, in percentage by mass: 0.01-1% of Mg element, 0.01-2% of Zn element, 0.01-2% of Si element, 0.01-1% of Ni element, 0.2-0.5% of Fe element, 1.6-2.4% of Mn element, 0.1-0.2% of Cu element and 0.02-0.2% of Ti element, the total content of inevitable impurities is ≤0.2%, and the balance is Al element. elements; wherein the sum of the mass contents of Mg and Zn is 1-3%, the sum of the mass contents of Si and Ni is 0.1-2.5%, and the sum of Fe, Si and Ni is 0.1-3%; the maximum size of the second phase in the anodized die-casting aluminum alloy is <40μm, the tensile strength of the anodized die-casting aluminum alloy is 150-180MPa, the yield strength of the anodized die-casting aluminum alloy is 60-80MPa, the elongation of the anodized die-casting aluminum alloy is 4-8%, and the thickness of the anodized die-casting aluminum alloy is 0.8-1.8mm.

[0008] Furthermore, the above-mentioned anodized die-casting aluminum alloy includes the following elements, in percentage by mass: 0.01-0.6% of Mg element, 0.01-1.8% of Zn element, 0.6-0.8% of Si element, 0.01-1% of Ni element, 0.25-0.3% of Fe element, 1.8-2.2% of Mn element, 0.1-0.2% of Cu element and 0.02-0.1% of Ti element, the total content of unavoidable impurities is ≤0.2%, and the balance is Al element.

[0009] Furthermore, the sum of the mass contents of Mg and Zn is 2-2.4%; and / or the sum of the mass contents of Si and Ni is 1-1.5%; and / or the sum of the mass contents of Fe, Si and Ni is 1.25-1.8%.

[0010] Furthermore, the area ratio of the Fe-containing second phase in the anodized die-cast aluminum alloy is ≤6%, preferably ≤4%, and / or the maximum size of the Fe-containing second phase in the anodized die-cast aluminum alloy is ≤30 μm.

[0011] Furthermore, the surface color difference of the anodized die-cast aluminum alloy is less than 0.4, and / or the white brightness L of the anodized die-cast aluminum alloy is greater than or equal to 70.

[0012] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned anodized die-cast aluminum alloy, the preparation method comprising: step S1, wherein raw materials comprising Al ingots, Zn ingots, Al-Mn master alloys, Al-Si master alloys, Al-Ni master alloys, Al-Cu master alloys, and iron agents are sequentially batched and first smelted, and then Mg ingots are added for second smelting to obtain a first melt; step S2, wherein the raw materials comprising the first melt, a refining agent, and an AlTiB refiner are sequentially stirred, degassed, and cast to obtain an ingot; and step S3, wherein the ingot is sequentially subjected to a third smelting, die-casting, and anodizing treatment to obtain an anodized die-cast aluminum alloy; wherein the temperature of the first smelting is 780 to 820° C., the time of the anodizing treatment is 10 to 18 min, the anodizing treatment comprises chemical polishing, and the time of the chemical polishing is 50 to 70 s.

[0013] Furthermore, in the above step S1, the temperature of the second smelting is 740-760°C.

[0014] Furthermore, the above step S2 also includes: standing and slagging in sequence after degassing; and / or, degassing in a nitrogen or argon atmosphere, the degassing time is 10 to 15 minutes; and / or, the standing time is 15 to 20 minutes; and / or, the mass ratio of the first melt, the AlTiB refiner and the refining agent is 1000:0.1 to 0.3:0.1 to 0.3; and / or, the stirring time is 3 to 5 minutes, and / or, the casting temperature is 720 to 740°C, and / or, the casting mold temperature is 180 to 200°C.

[0015] Furthermore, the area ratio of the Fe-containing second phase in the ingot is ≤7%, preferably ≤6%, and / or the maximum size of the Fe-containing second phase in the ingot is ≤60 μm.

[0016] Furthermore, in the above step S3, the third smelting is first heated to 770-800°C for insulation and then cooled to 740-760°C, and / or the die-casting time is ≤5h; preferably ≤4h, and / or the die-casting temperature is 720-740°C, and / or the die-casting mold temperature is 180-250°C.

[0017] By applying the technical solution of the present invention, the anodized die-casting aluminum alloy of the present application can improve the strength of the anodized die-casting aluminum alloy by adding Mg and Zn elements, thereby preventing the anodized die-casting aluminum alloy from being too soft after die-casting, which causes the anodized die-casting aluminum alloy to deform after demolding and ejection. However, excessive addition of Mg and Zn elements will reduce the fluidity of the melt, thereby affecting the forming performance of the anodized die-casting aluminum alloy. Adding 0.1 to 0.2% of Cu element can make it completely dissolved into the matrix during the corresponding rapid cooling process, which is not only conducive to improving the solid solution strengthening of the alloy, but also can improve the overall electrochemical activity of the anodized die-casting aluminum alloy. At the same time, in the anodizing stage, by coordinating the chemical polishing process of the Cu element content, the brightness of the anodized die-casting aluminum alloy can be further improved. By controlling the Fe element, Si element, Ni element and Ti element within the above range, and controlling the sum of the mass contents of Fe element, Si element and Ni element within the above range, it is possible to prevent the appearance of a coarse Fe-containing second phase in the anodized die-casting aluminum alloy, thereby reducing the deterioration of the strength and anodizing performance of the anodized die-casting aluminum alloy by the Fe-containing second phase, thereby reducing the surface color difference of the anodized die-casting aluminum alloy and improving the yield of the anodized die-casting aluminum alloy. In addition, by controlling the mass content of the Si element to be below 2%, the fluidity of the melt can be improved, the formation of large-sized second phases can be reduced, and the effect of anodizing will not be affected. Adding less than 1% of the Ni element can also provide latent heat of crystallization for the alloy to a certain extent, thereby providing energy for the front melt during the solidification process of the alloy, thereby improving the fluidity of the melt, but adding a large amount of Ni element will increase the size of the second phase and affect the anodizing effect. At the same time, in order to ensure the fluidity of the alloy melt, controlling the sum of the mass contents of the Si element and the Ni element within the above range can further improve the fluidity of the melt. By regulating the above elements, the melt can have higher fluidity and anti-adhesive properties, so that the anodized die-casting aluminum alloy can be better used in the production of thin-walled products with a thickness of 0.8 to 1.8 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 The metallographic photograph of the anodized die-cast aluminum alloy in Example 1 of the present application is shown. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] As analyzed in the background technology of this application, there are problems in the prior art such as that anodized die-cast aluminum alloys are difficult to form when preparing thin-walled products with relatively thin thickness, are easily deformed during the demolding process, and have low surface quality and yield rate of anodized die-cast aluminum alloys. In order to solve the above problems, this application provides an anodized die-cast aluminum alloy and a preparation method thereof.

[0022] In a typical embodiment of the present application, an anodized die-cast aluminum alloy is provided, which includes the following elements, by mass percentage: 0.01-1% of Mg element, 0.01-2% of Zn element, 0.01-2% of Si element, 0.01-1% of Ni element, 0.2-0.5% of Fe element, 1.6-2.4% of Mn element, 0.1-0.2% of Cu element and 0.02-0.2% of Ti element, the total content of unavoidable impurities is ≤0.2%, and the balance is Al element; Among them, the sum of the mass contents of Mg and Zn elements is 1-3%, the sum of the mass contents of Si and Ni elements is 0.1-2.5%, and the sum of Fe, Si and Ni elements is 0.1-3%; the maximum size of the second phase in the anodized die-casting aluminum alloy is <40μm, the tensile strength of the anodized die-casting aluminum alloy is 150-180MPa, the yield strength of the anodized die-casting aluminum alloy is 60-80MPa, the elongation of the anodized die-casting aluminum alloy is 4-8%, and the thickness of the anodized die-casting aluminum alloy is 0.8-1.8mm.

[0023] The anodized die-cast aluminum alloy of the present application can improve the strength of the anodized die-cast aluminum alloy by adding Mg and Zn elements, thereby preventing the anodized die-cast aluminum alloy from being too soft after die-casting, resulting in deformation of the anodized die-cast aluminum alloy after demolding and ejection. However, excessive addition of Mg and Zn elements will reduce the fluidity of the melt, thereby affecting the forming performance of the anodized die-cast aluminum alloy. Adding 0.1 to 0.2% of the Cu element can make it completely dissolved into the matrix during the corresponding rapid cooling process, which is not only conducive to improving the solid solution strengthening of the alloy, but also can improve the overall electrochemical activity of the anodized die-cast aluminum alloy. At the same time, in the anodizing stage, the brightness of the anodized die-cast aluminum alloy can be further improved by coordinating the chemical polishing process with the Cu element content. By controlling the Fe element, Si element, Ni element and Ti element within the above range, and controlling the sum of the mass contents of Fe element, Si element and Ni element within the above range, it is possible to prevent the appearance of a coarse Fe-containing second phase in the anodized die-casting aluminum alloy, thereby reducing the deterioration of the strength and anodizing performance of the anodized die-casting aluminum alloy by the Fe-containing second phase, thereby reducing the surface color difference of the anodized die-casting aluminum alloy and improving the yield of the anodized die-casting aluminum alloy. In addition, by controlling the mass content of the Si element to be below 2%, the fluidity of the melt can be improved, the formation of large-sized second phases can be reduced, and the effect of anodizing will not be affected. Adding less than 1% of the Ni element can also provide latent heat of crystallization for the alloy to a certain extent, thereby providing energy for the front melt during the solidification process of the alloy, thereby improving the fluidity of the melt, but adding a large amount of Ni element will increase the size of the second phase and affect the anodizing effect. At the same time, in order to ensure the fluidity of the alloy melt, controlling the sum of the mass contents of the Si element and the Ni element within the above range can further improve the fluidity of the melt. By regulating the above elements, the melt can have higher fluidity and anti-adhesive properties, so that the anodized die-casting aluminum alloy can be better used in the production of thin-walled products with a thickness of 0.8 to 1.8 mm.

[0024] In order to further improve the surface quality and strength of the anodized die-cast aluminum alloy, in one embodiment of the present application, the anodized die-cast aluminum alloy includes the following elements, by mass percentage: 0.01-0.6% of Mg element, 0.01-1.8% of Zn element, 0.6-0.8% of Si element, 0.01-1% of Ni element, 0.25-0.3% of Fe element, 1.8-2.2% of Mn element, 0.1-0.2% of Cu element and 0.02-0.1% of Ti element, the total content of unavoidable impurities is ≤0.2%, and the balance is Al element.

[0025] In one embodiment of the present application, the sum of the mass contents of Mg and Zn is 2-2.4%; and / or the sum of the mass contents of Si and Ni is 1-1.5%; and / or the sum of the mass contents of Fe, Si and Ni is 1.25-1.8%.

[0026] It is preferred to control the sum of the mass contents of the Mg element and the Zn element within the above range, which helps to improve the synergistic effect of the Mg element and the Zn element, thereby helping to further improve the strength and forming performance of the anodized die-casting aluminum alloy. It is preferred to control the sum of the mass contents of the Si element and the Ni element within the above range, which helps to enhance the strengthening effect of the Si element and the Ni element, thereby helping to further improve the fluidity and anti-viscosity performance of the melt. It is preferred to control the sum of the mass contents of the Fe element, the Si element and the Ni element within the above range, which helps to further alleviate the appearance of a coarse Fe-containing second phase in the anodized die-casting aluminum alloy, thereby helping to reduce the surface color difference of the anodized die-casting aluminum alloy, and further improve the yield of the anodized die-casting aluminum alloy.

[0027] In one embodiment of the present application, the area ratio of the Fe-containing second phase in the anodized die-cast aluminum alloy is ≤6%, preferably ≤4%, and / or the maximum size of the Fe-containing second phase in the anodized die-cast aluminum alloy is ≤30 μm.

[0028] It is preferred to control the area ratio of the Fe-containing second phase and the maximum size of the Fe-containing second phase in the anodized die-cast aluminum alloy within the above-mentioned range, which helps to reduce the deteriorating effect of the Fe-containing second phase on the strength and anodizing performance of the anodized die-cast aluminum alloy, thereby helping to reduce the surface color difference of the anodized die-cast aluminum alloy, and further helping to improve the yield of the anodized die-cast aluminum alloy.

[0029] In one embodiment of the present application, the surface color difference of the anodized die-cast aluminum alloy is less than 0.4, and / or the white brightness L of the anodized die-cast aluminum alloy is greater than or equal to 70, thereby being more conducive to meeting the appearance requirements of thin-walled products.

[0030] In another typical embodiment of the present application, a method for preparing the above-mentioned anodized die-cast aluminum alloy is provided, and the preparation method comprises: step S1, wherein raw materials including Al ingots, Zn ingots, Al-Mn master alloys, Al-Si master alloys, Al-Ni master alloys, Al-Cu master alloys, and iron agents are sequentially batched and first smelted, and then Mg ingots are added for second smelting to obtain a first melt; step S2, wherein the raw materials including the first melt, refining agent, and AlTiB refiner are sequentially stirred, degassed, and cast to obtain an ingot; and step S3, wherein the ingot is sequentially subjected to a third smelting, die-casting, and anodizing treatment to obtain an anodized die-cast aluminum alloy; wherein the temperature of the first smelting is 780 to 820° C., the time of the anodizing treatment is 10 to 18 min, and the anodizing treatment includes chemical polishing, and the time of the chemical polishing is 50 to 70 s.

[0031] The present application can effectively improve the fluidity and anti-adhesive film performance of the melt through the strengthening effect between the elements in the raw materials of the anodized die-casting aluminum alloy, so that the anodized die-casting aluminum alloy can be better used to produce thin-walled products with a thickness of 0.8 to 1.8 mm. At the same time, controlling the time of anodizing treatment and chemical polishing within the above range can better match the content of Cu element in the raw materials, thereby further improving the gloss and brightness of the anodized die-casting aluminum alloy. Specifically, step S1 can fully melt the above raw materials, so that the element components in the first melt are evenly distributed. Among them, by controlling the temperature of the first smelting within the above range, and adding Al-Si master alloy to the raw materials instead of the traditional Si agent, the speed and uniformity of its melting can be improved, thereby preventing the formation of a large-sized second phase and avoiding affecting the effective effect of the Si element. When preparing the ingot, refining and degassing are carried out through step S2, which can reduce impurities and gases in the melt, thereby improving the quality of the melt. The ingot is subjected to a third smelting, which can further refine the grains and improve the fluidity of the third melt, thereby facilitating subsequent die casting and anodizing treatment.

[0032] In one embodiment of the present application, in the above step S1, the temperature of the second smelting is 740-760°C.

[0033] It is preferable to control the temperature of the second smelting to be within the above range, which helps to fully melt the Mg ingot and reduce the burn-off amount of the Mg ingot.

[0034] In one embodiment of the present application, the above-mentioned step S2 also includes: standing and slagging in sequence after degassing; and / or, degassing is performed in a nitrogen or argon atmosphere, and the degassing time is 10 to 15 minutes; and / or, the standing time is 15 to 20 minutes; and / or, the mass ratio of the first melt, the AlTiB refiner and the refining agent is 1000:0.1 to 0.3:0.1 to 0.3; and / or, the stirring time is 3 to 5 minutes, and / or, the casting temperature is 720 to 740°C, and / or, the casting mold temperature is 180 to 200°C.

[0035] It is preferred to control the mass ratio of the first melt, the AlTiB refiner and the refining agent and the stirring time within the above range, and the type of the refining agent is preferably chloride salt, and more preferably zinc chloride, manganese chloride and ferric chloride, which helps to fully mix the first melt, the AlTiB refiner and the refining agent, thereby helping to purify the melt. It is preferred to degas in a nitrogen or argon atmosphere, and control the degassing time within the above range, which helps to further reduce impurities and gases in the melt, thereby helping to further improve the quality of the melt. It is preferred to perform standing and slagging in sequence after degassing, and control the standing time within the above range, which helps to fully release the gas in the melt, and slagging is beneficial to remove impurities in the melt.

[0036] In one embodiment of the present application, the area ratio of the Fe-containing second phase in the ingot is ≤7%, preferably ≤6%, and / or the maximum size of the Fe-containing second phase in the ingot is ≤60 μm.

[0037] It is preferred to control the area ratio of the Fe-containing second phase and the maximum size of the Fe-containing second phase in the ingot within the above-mentioned range, which helps to mitigate the deteriorating effect of the Fe-containing second phase on the strength and anodizing performance of the ingot, thereby helping to reduce the surface color difference of the anodized die-cast aluminum alloy and improve the yield of the anodized die-cast aluminum alloy.

[0038] In one embodiment of the present application, in the above step S3, the third smelting is to first heat the temperature to 770-800°C for insulation and then cool the temperature to 740-760°C, and / or the die-casting time is ≤5h; preferably ≤4h, and / or the die-casting temperature is 720-740°C, and / or the die-casting mold temperature is 180-250°C.

[0039] It is preferred that the temperature and time of the third smelting, the temperature and time of the die casting, and the mold temperature are within the above ranges, which helps to ensure that the third melt and the mold are both kept in a higher temperature range, thereby helping to improve the fluidity of the melt during the die casting process, while preventing rapid cooling caused by low mold temperature, so that the alloy melt is full of complex parts structure. On the other hand, during the production of die castings, due to the large temperature difference between the mold temperature and the melt temperature, it is easy to form a large internal stress. In the process of ejecting the die casting, the die casting is prone to deformation, especially for thin-walled products, which is more likely to cause deformation problems, resulting in direct scrapping of the parts. Therefore, the die casting mold temperature is controlled within the above range and maintained at a stable temperature, which helps to reduce the temperature difference between the mold and the melt. In addition, it is preferred to control the die casting temperature, time and mold temperature within the above ranges, which helps to promote the forming of anodized die-casting aluminum alloys, thereby helping to produce thin-walled products with a thickness of 0.8 to 1.8 mm. And controlling the die casting time within the above range helps to alleviate the excessively long high temperature insulation time, which leads to severe air inhalation and causes air entrainment in the finished product, thereby affecting the forming properties of the anodized die-casting aluminum alloy.

[0040] The beneficial effects of the present application will be further illustrated below in conjunction with embodiments.

[0041] Example 1

[0042] In terms of mass percentage, the anodized die-casting aluminum alloy raw material is smelted according to the composition ratio of 1% Mg element, 1% Zn element, 0.6% Si element, 0.4% Ni element, 0.25% Fe element, 1.6% Mn element, 0.1% Cu element, 0.02% Ti element, and the balance Al element. Specifically, the raw materials including Al ingot, Zn ingot, Al-Mn master alloy, Al-Cu master alloy, Al-Si master alloy, and iron agent are batched and smelted in sequence, and then Mg ingot is added for second smelting to obtain a first melt, wherein the temperature of the first smelting is 780°C and the temperature of the second smelting is 740°C.

[0043] The raw materials including 300 kg of the first melt, 30 g of the refining agent ferric chloride and 30 g of the AlTiB refiner were stirred for 3 minutes, degassed in a nitrogen atmosphere for 10 minutes, allowed to stand for 15 minutes, deslagging and cast to obtain an ingot, wherein the casting temperature was 720°C and the casting mold temperature was 180°C.

[0044] The ingot is put into the melting furnace of the die casting machine for the third melting, specifically, the temperature is first raised to 770°C for insulation and then cooled to 740°C. After the third melting, die casting and anodizing treatment are performed to obtain anodized die-casting aluminum alloy, wherein the die casting temperature is 720°C, the die casting time is 5h, the die casting mold temperature is 180°C, the anodizing treatment time is 10min, and the anodizing treatment includes chemical polishing, wherein the chemical polishing time is 50s.

[0045] Example 2

[0046] In terms of mass percentage, the anodized die-casting aluminum alloy raw material is smelted according to the composition ratio of 0.4% Mg element, 2% Zn element, 1.4% Si element, 0.01% Ni element, 0.3% Fe element, 2% Mn element, 0.15% Cu element, 0.1% Ti element, and the balance Al element. Specifically, the raw materials including Al ingot, Zn ingot, Al-Mn master alloy, Al-Cu master alloy, Al-Si master alloy, and iron agent are sequentially batched and first smelted, and then Mg ingot is added for second smelting to obtain a first melt, wherein the temperature of the first smelting is 800° C. and the temperature of the second smelting is 750° C.

[0047] The raw materials including 300 kg of the first melt, 60 g of the refining agent ferric chloride and 60 g of the AlTiB refiner were stirred for 4 minutes, degassed in a nitrogen atmosphere for 12 minutes, allowed to stand for 18 minutes, deslagging and cast to obtain an ingot, wherein the casting temperature was 730°C and the casting mold temperature was 190°C.

[0048] The ingot is put into the melting furnace of the die casting machine for the third melting. Specifically, the temperature is first raised to 790°C for insulation and then cooled to 750°C for insulation. After the third melting, die casting and anodizing treatment are performed to obtain anodized die-casting aluminum alloy, wherein the die casting temperature is 730°C, the die casting time is 4h, the die casting mold temperature is 215°C, the anodizing treatment time is 15min, and the anodizing treatment includes chemical polishing, wherein the chemical polishing time is 60s.

[0049] Example 3

[0050] In terms of mass percentage, the anodized die-casting aluminum alloy raw material is smelted according to the composition ratio of 0.01% Mg element, 2% Zn element, 0.5% Si element, 1% Ni element, 0.5% Fe element, 2.4% Mn element, 0.2% Cu element, 0.2% Ti element, and the balance Al element. Specifically, the raw materials including Al ingot, Zn ingot, Al-Mn master alloy, Al-Cu master alloy, Al-Si master alloy, and iron agent are sequentially batched and first smelted, and then Mg ingot is added for second smelting to obtain a first melt, wherein the temperature of the first smelting is 820°C and the temperature of the second smelting is 760°C.

[0051] The raw materials including 300 kg of the first melt, 90 g of the refining agent ferric chloride and 90 g of the AlTiB refiner were stirred for 5 minutes, degassed in a nitrogen atmosphere for 15 minutes, allowed to stand for 20 minutes, deslagging and cast to obtain an ingot, wherein the casting temperature was 740°C and the casting mold temperature was 200°C.

[0052] The ingot is put into the melting furnace of the die casting machine for the third melting, specifically, the temperature is first raised to 800°C for insulation and then cooled to 760°C for insulation. After the third melting, die casting and anodizing treatment are performed to obtain anodized die-casting aluminum alloy, wherein the die casting temperature is 740°C, the die casting time is 3h, the die casting mold temperature is 250°C, the anodizing treatment time is 18min, and the anodizing treatment includes chemical polishing, wherein the chemical polishing time is 70s.

[0053] Example 4

[0054] The difference from Example 1 is that the mass content of Mg element is 0.2%, the mass content of Zn element is 1.8%, and the total mass content of Mg element and Zn element is 2%, and finally an anodized die-casting aluminum alloy is obtained.

[0055] Example 5

[0056] The difference from Example 1 is that the mass content of Mg element is 0.6%, the mass content of Zn element is 1.8%, and the total mass content of Mg element and Zn element is 2.4%, and finally an anodized die-casting aluminum alloy is obtained.

[0057] Example 6

[0058] The difference from Example 1 is that the mass content of Mg element is 1%, the mass content of Zn element is 0.5%, and the total mass content of Mg element and Zn element is 1.5%, and finally an anodized die-casting aluminum alloy is obtained.

[0059] Example 7

[0060] The difference from Example 1 is that the mass content of Si element is 0.5%, the mass content of Ni element is 0.5%, and the total mass content of Si element and Ni element is 1%, and finally an anodized die-casting aluminum alloy is obtained.

[0061] Example 8

[0062] The difference from Example 1 is that the mass content of Si element is 1%, the mass content of Ni element is 0.5%, and the total mass content of Si element and Ni element is 1.5%, and finally an anodized die-casting aluminum alloy is obtained.

[0063] Example 9

[0064] The difference from Example 1 is that the mass content of Si element is 0.1%, the mass content of Ni element is 0.01%, and the total mass content of Si element and Ni element is 0.11%, and finally an anodized die-casting aluminum alloy is obtained.

[0065] Example 10

[0066] The difference from Example 1 is that the mass content of Fe element is 0.25%, the mass content of Si element is 0.4%, the mass content of Ni element is 0.6%, and the total mass content of Fe element, Si element and Ni element is 1.25%, and finally an anodized die-cast aluminum alloy is obtained.

[0067] Embodiment 11

[0068] The difference from Example 1 is that the mass content of Fe element is 0.5%, the mass content of Si element is 1%, the mass content of Ni element is 0.3%, and the total mass content of Fe element, Si element and Ni element is 1.8%, and finally an anodized die-cast aluminum alloy is obtained.

[0069] Example 12

[0070] The difference from Example 1 is that the mass content of Fe element is 0.4%, the mass content of Si element is 1.3%, the mass content of Ni element is 0.8%, and the total mass content of Fe element, Si element and Ni element is 2.5%, and finally an anodized die-cast aluminum alloy is obtained.

[0071] Example 13

[0072] The difference from Example 1 is that the temperature of the first smelting is 820° C., and an anodized die-cast aluminum alloy is finally obtained.

[0073] Embodiment 14

[0074] The difference from Example 1 is that the anodizing treatment time is 18 minutes, the anodizing treatment includes chemical polishing, and the chemical polishing time is 70 seconds, and finally an anodized die-cast aluminum alloy is obtained.

[0075] Embodiment 15

[0076] The difference from Example 1 is that the total mass of the first melt, AlTiB refiner and refining agent ferric chloride is 300.06 kg, the mass ratio of the first melt, AlTiB refiner and refining agent ferric chloride is 1000:0.3:0.3, and finally anodized die-casting aluminum alloy is obtained.

[0077] Example 16

[0078] The difference from Example 1 is that the total mass of the first melt, AlTiB refiner and refining agent ferric chloride is 300.06 kg, the mass ratio of the first melt, AlTiB refiner and refining agent ferric chloride is 1000:0.5:0.5, and finally anodized die-casting aluminum alloy is obtained.

[0079] Comparative Example 1

[0080] The difference from Example 1 is that, in terms of mass percentage, the raw material of the anodized die-casting aluminum alloy is smelted according to the composition ratio of 2% Mg element, 2% Zn element, 0.6% Si element, 0.4% Ni element, 0.25% Fe element, 1.6% Mn element, 0.1% Cu element, 0.02% Ti element, and the balance Al element. Specifically, the raw materials including Al ingot, Zn ingot, Al-Mn master alloy, Al-Cu master alloy, Al-Si master alloy, and iron agent are sequentially batched and first smelted, and then Mg ingot is added for second smelting to obtain a first melt, and finally the anodized die-casting aluminum alloy is obtained.

[0081] Comparative Example 2

[0082] The difference from Example 1 is that, in terms of mass percentage, the raw material of the anodized die-casting aluminum alloy is smelted according to the composition ratio of 1% Mg element, 1% Zn element, 3% Si element, 1.5% Ni element, 0.2% Fe element, 1.6% Mn element, 0.1% Cu element, 0.02% Ti element, and the balance Al element. Specifically, the raw materials including Al ingot, Zn ingot, Al-Mn master alloy, Al-Cu master alloy, Al-Si master alloy, and iron agent are sequentially batched and first smelted, and then Mg ingot is added for second smelting to obtain a first melt, and finally the anodized die-casting aluminum alloy is obtained.

[0083] Comparative Example 3

[0084] The difference from Example 1 is that, in terms of mass percentage, the raw material of the anodized die-casting aluminum alloy is smelted according to the composition ratio of 1% Mg element, 1% Zn element, 1% Si element, 1.5% Ni element, 0.8% Fe element, 1.6% Mn element, 0.1% Cu element, 0.02% Ti element, and the balance Al element. Specifically, the raw materials including Al ingot, Zn ingot, Al-Mn master alloy, Al-Cu master alloy, Al-Si master alloy, and iron agent are batched and smelted in sequence, and then Mg ingot is added for second smelting to obtain a first melt, and finally the anodized die-casting aluminum alloy is obtained.

[0085] Comparative Example 4

[0086] The difference from Example 1 is that the temperature of the first smelting is 850° C., and an anodized die-cast aluminum alloy is finally obtained.

[0087] Comparative Example 5

[0088] The difference from Example 1 is that the anodizing treatment time is 22 minutes, the anodizing treatment includes chemical polishing, and the chemical polishing time is 80 seconds, and finally an anodized die-cast aluminum alloy is obtained.

[0089] Comparative Example 6

[0090] The difference from Example 1 is that the chemical polishing time is 40 seconds, and an anodized die-cast aluminum alloy is finally obtained.

[0091] Test Method

[0092] Maximum size and average size test of the second phase: Tested in accordance with GB / T 15749-2008.

[0093] Area ratio and maximum size test of Fe-containing second phase: The second phase is distinguished according to the method of YST 1624-2023, and the Fe-containing phase is distinguished from the second phase and statistically analyzed.

[0094] Tensile strength, yield strength and elongation tests: Tested in accordance with GBT 228.1-2021.

[0095] Thickness test: Use thickness testing equipment such as vernier caliper or laser thickness gauge for measurement.

[0096] Surface color difference test: Use a colorimeter to test the surface color difference, take the L, a, b values ​​of more than 10 consecutive test points, and calculate the color difference △E=(△L 2 +△a 2 +△b 2 ) ^2 .

[0097] White brightness L test: Use a colorimeter to test and take the average of the L values ​​of more than 10 consecutive points.

[0098] The ingots and anodized die-cast aluminum alloys of the above embodiments and comparative examples were subjected to performance tests. The test results are shown in Tables 1 and 2.

[0099] Table 1

[0100]

[0101]

[0102] Table 2

[0103]

[0104]

[0105] in, Figure 1 is a metallographic photograph of anodized die-cast aluminum alloy in Example 1, Figure 1 It can be seen that the structure of anodized die-cast aluminum alloy is uniform.

[0106] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0107] The anodized die-cast aluminum alloy of the present application can improve the strength of the anodized die-cast aluminum alloy by adding Mg and Zn elements, thereby preventing the anodized die-cast aluminum alloy from being too soft after die-casting, resulting in deformation of the anodized die-cast aluminum alloy after demolding and ejection. However, excessive addition of Mg and Zn elements will reduce the fluidity of the melt, thereby affecting the forming performance of the anodized die-cast aluminum alloy. Adding 0.1 to 0.2% of the Cu element can make it completely dissolved into the matrix during the corresponding rapid cooling process, which is not only conducive to improving the solid solution strengthening of the alloy, but also can improve the overall electrochemical activity of the anodized die-cast aluminum alloy. At the same time, in the anodizing stage, the brightness of the anodized die-cast aluminum alloy can be further improved by coordinating the chemical polishing process with the Cu element content. By controlling the Fe element, Si element, Ni element and Ti element within the above range, and controlling the sum of the mass contents of Fe element, Si element and Ni element within the above range, it is possible to prevent the appearance of a coarse Fe-containing second phase in the anodized die-casting aluminum alloy, thereby reducing the deterioration of the strength and anodizing performance of the anodized die-casting aluminum alloy by the Fe-containing second phase, thereby reducing the surface color difference of the anodized die-casting aluminum alloy and improving the yield of the anodized die-casting aluminum alloy. In addition, by controlling the mass content of the Si element to be below 2%, the fluidity of the melt can be improved, the formation of large-sized second phases can be reduced, and the effect of anodizing will not be affected. Adding less than 1% of the Ni element can also provide latent heat of crystallization for the alloy to a certain extent, thereby providing energy for the front melt during the solidification process of the alloy, thereby improving the fluidity of the melt, but adding a large amount of Ni element will increase the size of the second phase and affect the anodizing effect. At the same time, in order to ensure the fluidity of the alloy melt, controlling the sum of the mass contents of the Si element and the Ni element within the above range can further improve the fluidity of the melt. By regulating the above elements, the melt can have higher fluidity and anti-adhesive properties, so that the anodized die-casting aluminum alloy can be better used in the production of thin-walled products with a thickness of 0.8 to 1.8 mm.

[0108] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An anodized die-cast aluminum alloy, characterized in that: The anodized die-casting aluminum alloy includes the following elements in percentage by mass: 0.01-1% Mg element, 0.01-2% Zn element, 0.01-2% Si element, 0.01-1% Ni element, 0.2-0.5% Fe element, 1.6-2.4% Mn element, 0.1-0.2% Cu element, 0.02-0.2% Ti element, the total content of unavoidable impurities is ≤0.2%, and the balance is Al element; wherein the sum of the mass contents of the Mg element and the Zn element is 1-3%, the sum of the mass contents of the Si element and the Ni element is 0.1-2.5%, and the sum of the Fe element, the Si element and the Ni element is 0.1-3%; The maximum size of the second phase in the anodized die-cast aluminum alloy is <40 μm, the tensile strength of the anodized die-cast aluminum alloy is 150 to 180 MPa, the yield strength of the anodized die-cast aluminum alloy is 60 to 80 MPa, the elongation of the anodized die-cast aluminum alloy is 4 to 8%, and the thickness of the anodized die-cast aluminum alloy is 0.8 to 1.8 mm.

2. The anodized die-cast aluminum alloy according to claim 1, characterized in that: The anodized die-casting aluminum alloy includes the following elements in percentage by mass: 0.01-0.6% Mg element, 0.01-1.8% Zn element, 0.6-0.8% Si element, 0.01-1% Ni element, 0.25-0.3% Fe element, 1.8-2.2% Mn element, 0.1-0.2% Cu element, 0.02-0.1% Ti element, the total content of unavoidable impurities is ≤0.2%, and the balance is Al element.

3. The anodized die-cast aluminum alloy according to claim 1 or 2, characterized in that: The sum of the mass contents of the Mg element and the Zn element is 2-2.4%; and / or the sum of the mass contents of the Si element and the Ni element is 1-1.5%; and / or the sum of the mass contents of the Fe element, the Si element and the Ni element is 1.25-1.8%.

4. The anodized die-cast aluminum alloy according to any one of claims 1 to 3, characterized in that: The area ratio of the Fe-containing second phase in the anodized die-cast aluminum alloy is ≤6%, preferably ≤4%, and / or the maximum size of the Fe-containing second phase in the anodized die-cast aluminum alloy is ≤30 μm.

5. The anodized die-cast aluminum alloy according to any one of claims 1 to 4, characterized in that: The surface color difference of the anodized die-cast aluminum alloy is less than 0.4, and / or the white brightness L of the anodized die-cast aluminum alloy is greater than or equal to 70.

6. A method for preparing the anodized die-cast aluminum alloy according to any one of claims 1 to 5, characterized in that: The preparation method comprises: Step S1, after sequentially batching and first smelting raw materials including Al ingot, Zn ingot, Al-Mn master alloy, Al-Si master alloy, Al-Ni master alloy, Al-Cu master alloy and iron agent, adding Mg ingot for second smelting to obtain a first melt; Step S2, stirring, degassing and casting the raw materials including the first melt, the refining agent and the AlTiB refiner in sequence to obtain an ingot; and Step S3, subjecting the ingot to a third smelting, die casting and anodizing treatment in sequence to obtain the anodized die-casting aluminum alloy; The temperature of the first smelting is 780-820° C., the time of the anodizing treatment is 10-18 minutes, the anodizing treatment includes chemical polishing, and the time of the chemical polishing is 50-70 seconds.

7. The preparation method according to claim 6, characterized in that: In the step S1, the temperature of the second smelting is 740-760°C.

8. The preparation method according to claim 6 or 7, characterized in that: The step S2 further comprises: after the degassing, sequentially standing and slagging; and / or, performing the degassing in a nitrogen or argon atmosphere, the degassing time being 10 to 15 minutes; and / or, the standing time being 15 to 20 minutes; And / or, the mass ratio of the first melt, the AlTiB refiner and the refining agent is 1000:0.1-0.3:0.1-0.3; and / or, the stirring time is 3-5 min, and / or, the casting temperature is 720-740° C., and / or, the casting mold temperature is 180-200° C.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The area proportion of the Fe-containing second phase in the ingot is ≤7%, preferably ≤6%, and / or the maximum size of the Fe-containing second phase in the ingot is ≤60 μm.

10. The preparation method according to any one of claims 6 to 9, characterized in that: In the step S3, the third smelting is to first heat up to 770-800°C for insulation and then cool down to 740-760°C, and / or the die-casting time is ≤5h; preferably ≤4h, and / or the die-casting temperature is 720-740°C, and / or the die-casting mold temperature is 180-250°C.

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