A preparation process of aluminum alloy material for super-large size die castings

Abstract

The present invention discloses a preparation process of an aluminum alloy material for oversized die castings, and relates to the technical field of metal materials. When preparing an aluminum alloy material for oversized die castings, the present invention includes the following components by mass percentage: 0.7-0.9% iron, 0.35-0.45% manganese, 7-9% silicon, 1.8-2.1% zinc, 0.02-0.05% strontium, 0.4% lanthanum, 0.2% ytterbium, 0.03% copper, <0.05% magnesium, 0.2% antimony, and 1wt% Al-TCB seed alloy and 1wt% Al-B master alloy are added, and the remainder is aluminum and unavoidable impurities. The aluminum alloy material for oversized die castings prepared by the present invention does not require heat treatment, has excellent casting performance, good tensile strength, yield strength, elongation and thermal conductivity.

Description

Technical Field

[0001] The invention relates to the technical field of metal materials, and in particular to a preparation process of aluminum alloy materials for super-large-size die castings. Background Art

[0002] Aluminum and its alloys are widely used in aerospace, transportation, 5G communications, and construction materials due to their low density, high specific strength, and excellent electrical / thermal conductivity. Especially in the automotive field, aluminum alloys have been widely used in the automotive field since the 1970s. After more than 50 years of development, the use of aluminum alloys is second only to steel, and has become a key material in the automotive industry. In addition, environmental problems have become increasingly prominent in recent years. In response to the call for energy conservation and emission reduction, many industries have forced materials to develop in the direction of lightweight. Therefore, the use of aluminum materials has continued to increase and the scope of application has continued to expand. Replacing steel with aluminum has become the main development trend.

[0003] Die casting is a casting process widely used to produce automotive parts with high dimensional accuracy and low surface roughness. Compared with other material forming methods, die casting has a good economic benefit advantage in the production of large-scale automotive parts. However, the air entrainment phenomenon in the die casting process can cause hole defects in the casting, seriously deteriorating the mechanical properties of the parts. This phenomenon will be more serious in the production process of large castings. Studies have shown that adding vacuum auxiliary equipment in the die casting process to increase the vacuum degree of the die casting cavity can effectively improve the internal quality of the casting and reduce hole defects. Surface bubbling can also be well avoided in subsequent heat treatment. Therefore, the use of high vacuum assistance is very necessary for integrated die casting. In addition, due to the large size of integrated die castings, complex shapes, and drastic cross-sectional changes, the castings are very easy to deform at high temperatures. The high-temperature deformation of castings is fatal because it is very difficult to reshape large-sized thin-walled castings after deformation. Therefore, integrated die castings cannot be subjected to high-temperature solution treatment, which results in the inability to improve mechanical properties through T6 heat treatment. This requires that the integrated die casting alloys meet service requirements in the cast state or direct aging state. Therefore, it is very necessary and urgent to research and develop heat-treatment-free alloy materials suitable for integrated die casting. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation process of aluminum alloy material for super-large size die castings to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The invention discloses an aluminum alloy material for super-large-sized die castings. The aluminum alloy material for super-large-sized die castings comprises the following components by mass percentage: 0.7-0.9% iron, 0.35-0.45% manganese, 7-9% silicon, 1.8-2.1% zinc, 0.02-0.05% strontium, 0.2-0.4% lanthanum, 0.2-0.4% ytterbium, less than 0.03% copper, less than 0.05% magnesium, and 0.2% antimony, and 1wt% of Al-TCB seed alloy and 1wt% of Al-B master alloy are added, and the balance is aluminum and unavoidable impurities.

[0007] As an optimization, the impurity mass percentage is less than 0.3wt%.

[0008] As an optimization, the mass ratio of iron to manganese is (1.5~2.5):1.

[0009] A preparation process of an aluminum alloy material for an oversized die casting, comprising the following preparation steps:

[0010] (1) Material preparation: prepare the corresponding metal ingots or alloy intermediates according to the formula ratio;

[0011] (2) Alloy smelting: heat the furnace to 750-760°C and keep it warm, first put in some aluminum ingots, heat for 1-1.5 hours until the aluminum ingots are completely melted, heat to 800°C, add iron source and manganese source, stir for 15-20 minutes, add silicon source in 3 times, each time with an interval of 5-6 minutes, stir and keep warm for 30-40 minutes after the addition is completed, cool to 750°C, add zinc source, strontium source, lanthanum source, and ytterbium source, stir and keep warm for 40-45 minutes, cool to 730°C, add antimony source, stir and keep warm for 10-15 minutes, add 1wt% Al-B master alloy, stir and keep warm for 5-6 minutes, add 1wt% Al-TCB seed alloy and the remaining aluminum ingots, stir and keep warm for 20-25 minutes to obtain an alloy melt;

[0012] (3) Deslagging: Cool down to 720℃, add hexachloroethane refining agent for refining and deslagging, stir for 10-12 minutes, let stand for 5-6 minutes, scrape out the slag, and repeat 3 times;

[0013] (4) Degassing: Cool down to 700°C, use a four-tube degassing rake to blow argon into the alloy liquid, the argon outlet pressure is 0.5MPa, degas for 30 minutes, let it stand for 15 minutes, scrape out the slag, and obtain the alloy liquid;

[0014] (5) Vacuum die casting: The alloy liquid is subjected to vacuum die casting. The die casting process is set as follows: pouring temperature 680°C, air pressure <50mbar, injection force 330kN, injection time 3s, cooling time 2s, mold retention time 10s, mold temperature 150°C, to produce aluminum alloy materials for ultra-large size die castings.

[0015] As an optimization, the aluminum ingot in step (2) is one or more of pure aluminum, electrolytic aluminum or recycled aluminum, the iron source is an aluminum-iron master alloy, the manganese source is electrolytic manganese or an aluminum-manganese master alloy, the silicon source is single crystal silicon or an aluminum-silicon master alloy, the zinc source is metallic zinc or an aluminum-zinc master alloy, the strontium source is an aluminum-strontium master alloy, the lanthanum source is an aluminum-lanthanum master alloy, the ytterbium source is an aluminum-ytterbium master alloy, and the antimony source is an aluminum-antimony master alloy.

[0016] As an optimization, in step (2), all alloy raw materials except the aluminum ingot are wrapped in aluminum foil and added to the furnace.

[0017] As an optimization, the mass of the partial aluminum ingots in step (2) accounts for 70-75% of the total mass of the aluminum ingots to be added, and the mass of the remaining aluminum ingots is the mass of the aluminum ingots remaining after deducting the mass of the aluminum ingots and aluminum foil already added.

[0018] As an optimization, the hexachloroethane refining agent model in step (3) is TY-JL-1, and the added amount is 0.1-1% of the mass of the alloy melt.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0020] The aluminum alloy material for super-large-size die castings prepared by the present invention comprises the following components by mass percentage: 0.7-0.9% iron, 0.35-0.45% manganese, 7-9% silicon, 1.8-2.1% zinc, 0.02-0.05% strontium, 0.2-0.4% lanthanum, 0.2-0.4% ytterbium, less than 0.03% copper, less than 0.05% magnesium, 0.2% antimony, 1wt% Al-TCB seed alloy and 1wt% Al-B master alloy are further added, and the balance is aluminum and inevitable impurities; the casting is carried out by a vacuum die casting method.

[0021] First, the iron content in this formula can be controlled at a high level of 0.7~0.9%. By using the rapid cooling of vacuum die casting and adding manganese, the Al 13 Fe 4 The formation of Al 6(Fe, Mn)Si changes from eutectic state to hypoeutectic state, and its fibers become finer. At the same time, the formation of β-AlFeSi phase is inhibited. At the same time, due to the high iron content, the sticking phenomenon after die casting is greatly alleviated, and the amount of manganese added can be appropriately reduced. Due to the high tolerance to iron content, recycled aluminum with a high iron content can be appropriately used in the selection of aluminum raw materials, which reduces the cost of raw materials and improves the recycling rate of aluminum materials, reducing environmental pollution caused by the waste of raw materials; in order to better refine the grains of iron-rich phase, the manganese content needs to be controlled to reduce the generation of harmful phases; 7~9% silicon has good casting and filling properties, and no primary silicon will appear, and has good shrinkage; the added zinc element promotes the simultaneous nucleation of α-Al in the cavity, which leads to a significant increase in the thickness of the fine grain zone on the surface of the die-casting alloy, and reduces the aspect ratio of the eutectic Si phase. Due to the extremely high solid solubility of zinc in aluminum alloy, and solidification at a high cooling rate of vacuum die casting, no Zn-rich phase is produced. At the same time, the natural aging characteristics of zinc are used to ensure the long-term stability of the alloy strength.

[0022] Secondly, strontium, as a modifier of Si phase, can effectively improve the morphology of eutectic silicon, changing it from needle-shaped, flake-shaped to short rod-shaped, avoiding the splitting of the aluminum matrix, and effectively improving the strength and toughness of the alloy; lanthanum and ytterbium, as rare earth elements, can effectively refine the grains with appropriate addition, while improving the morphology of the iron phase, changing it from agglomerated, long needle-shaped to dispersed, fine, dispersed, and short rod-shaped, and also improving the morphology of eutectic silicon, and the fluidity of the alloy is also improved, effectively improving the strength and toughness of the alloy; in this formula, the content of copper and magnesium needs to be controlled to avoid the formation of harmful phases that lead to a decrease in the strength of the alloy; the addition of antimony has an effect on the Si phase It has a certain metamorphic effect, which can refine the α-Al and eutectic Si phases in the alloy. Antimony can generate AlSb phase with aluminum, promote the early precipitation of α-Al and inhibit the growth of silicon phase. The addition of antimony improves the thermal conductivity of the alloy. The antimony metamorphism has a low burnout rate and a long effective time. It can be repeatedly remelted and has the characteristics of permanent metamorphism. However, it needs to be matched with a high cooling rate to better show its metamorphic effect. Therefore, it needs to be matched with vacuum die-casting technology with a high cooling rate. It is suitable for large-sized thin-walled die-castings; Al-B master alloy and Al-TCB seed alloy have a synergistic refining effect, which can effectively refine the grain size, and there is no TiB 2 The "silicon" poisoning phenomenon occurs when the refiner is used. Its efficient nucleation substrate is a three-layer structure of complex phase nucleation particles, which effectively improves the mechanical strength of the alloy.

[0023] Finally, when smelting the alloy, other metal raw materials are wrapped in aluminum foil and added to the furnace to prevent them from oxidizing rapidly and being unable to dissolve into the melt, resulting in the actual composition of the alloy not being consistent with the designed composition; the aluminum alloy is cast using a vacuum die-casting method with a high cooling rate, and its high cooling rate is used to improve the refinement of the iron phase, thereby increasing the tolerance to iron and enhancing the mechanical strength of the alloy. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] The metal raw materials used in all the following examples and comparative examples are:

[0026] Aluminum ingot: electrolytic aluminum A00 ingot, model AL99.70A, impurity content less than 0.3%;

[0027] Iron source: aluminum-iron master alloy, model ALFe20;

[0028] Manganese source: aluminum-manganese master alloy, model ALMn10;

[0029] Silicon source: industrial single crystal silicon, model Si1101;

[0030] Zinc source: metallic zinc, model 1#;

[0031] Strontium source: aluminum strontium master alloy, model ALSr10;

[0032] Lanthanum source: aluminum-lanthanum master alloy, model ALLa10;

[0033] Ytterbium source: aluminum-ytterbium master alloy, model ALYb10;

[0034] Antimony source: aluminum antimony master alloy, model ALSb4;

[0035] Al-B master alloy: model ALB3;

[0036] Al-TCB seed alloy: model is AlTiCB, purchased from Shandong Lvmei Melt Technology Co., Ltd. Example

[0037] A preparation process of an aluminum alloy material for an oversized die casting, the preparation process of an aluminum alloy material for an oversized die casting comprising the following preparation steps:

[0038] The composition includes the following components by mass percentage: 0.7% iron, 0.35% manganese, 7% silicon, 1.8% zinc, 0.02% strontium, 0.4% lanthanum, 0.2% ytterbium, <0.03% copper, <0.05% magnesium, 0.2% antimony, 1wt% Al-TCB seed alloy and 1wt% Al-B master alloy, and the balance is aluminum and unavoidable impurities;

[0039] (1) Material preparation: prepare the corresponding metal ingots or alloy intermediates according to the formula ratio;

[0040] (2) Alloy smelting: heat the furnace to 750°C and keep it warm, first put in some aluminum ingots, heat for 1.5 hours until the aluminum ingots are completely melted, heat to 800°C, add iron source and manganese source, stir for 15 minutes, add silicon source in 3 times, each time with an interval of 5 minutes, stir and keep warm for 30 minutes after the addition is completed, cool to 750°C, add zinc source, strontium source, lanthanum source, and ytterbium source, stir and keep warm for 40 minutes, cool to 730°C, add antimony source, stir and keep warm for 10 minutes, add 1wt% Al-B master alloy, stir and keep warm for 5 minutes, add 1wt% Al-TCB seed alloy and the remaining aluminum ingots, stir and keep warm for 20 minutes to obtain an alloy melt;

[0041] (3) Slag removal: Cool down to 720℃, add hexachloroethane refining agent for refining and slag removal, stir for 10 minutes, let stand for 6 minutes, scrape out the slag, and repeat 3 times;

[0042] (4) Degassing: Cool down to 700°C, use a four-tube degassing rake to blow argon into the alloy liquid, the argon outlet pressure is 0.5MPa, degas for 30 minutes, let it stand for 15 minutes, scrape out the slag, and obtain the alloy liquid;

[0043] (5) Vacuum die casting: The alloy liquid is subjected to vacuum die casting. The die casting process is set as follows: pouring temperature 680°C, air pressure <50mbar, injection force 330kN, injection time 3s, cooling time 2s, mold retention time 10s, mold temperature 150°C, to produce aluminum alloy materials for ultra-large size die castings. Example

[0044] A preparation process of an aluminum alloy material for an oversized die casting, the preparation process of an aluminum alloy material for an oversized die casting comprising the following preparation steps:

[0045] The composition includes the following components by mass percentage: 0.8% iron, 0.40% manganese, 8% silicon, 1.95% zinc, 0.03% strontium, 0.3% lanthanum, 0.3% ytterbium, <0.03% copper, <0.05% magnesium, 0.2% antimony, 1wt% Al-TCB seed alloy and 1wt% Al-B master alloy, and the balance is aluminum and unavoidable impurities;

[0046] (1) Material preparation: prepare the corresponding metal ingots or alloy intermediates according to the formula ratio;

[0047] (2) Alloy smelting: heat the furnace to 755°C and keep it warm, first put in some aluminum ingots, heat for 1.2 hours until the aluminum ingots are completely melted, heat to 800°C, add iron source and manganese source, stir for 18 minutes, add silicon source in 3 times, each time with an interval of 6 minutes, stir and keep warm for 35 minutes after the addition is completed, cool to 750°C, add zinc source, strontium source, lanthanum source, and ytterbium source, stir and keep warm for 40 minutes, cool to 730°C, add antimony source, stir and keep warm for 15 minutes, add 1wt% Al-B master alloy, stir and keep warm for 6 minutes, add 1wt% Al-TCB seed alloy and the remaining aluminum ingots, stir and keep warm for 20 minutes to obtain an alloy melt;

[0048] (3) Slag removal: Cool down to 720℃, add hexachloroethane refining agent for refining and slag removal, stir for 11 minutes, let stand for 5 minutes, scrape out the slag, and repeat 3 times;

[0049] (4) Degassing: Cool down to 700°C, use a four-tube degassing rake to blow argon into the alloy liquid, the argon outlet pressure is 0.5MPa, degas for 30 minutes, let it stand for 15 minutes, scrape out the slag, and obtain the alloy liquid;

[0050] (5) Vacuum die casting: The alloy liquid is subjected to vacuum die casting. The die casting process is set as follows: pouring temperature 680°C, air pressure <50mbar, injection force 330kN, injection time 3s, cooling time 2s, mold retention time 10s, mold temperature 150°C, to produce aluminum alloy materials for ultra-large size die castings. Example

[0051] A preparation process of an aluminum alloy material for an oversized die casting, the preparation process of an aluminum alloy material for an oversized die casting comprising the following preparation steps:

[0052] The composition includes the following components by mass percentage: 0.9% iron, 0.45% manganese, 9% silicon, 2.1% zinc, 0.05% strontium, 0.2% lanthanum, 0.4% ytterbium, <0.03% copper, <0.05% magnesium, 0.2% antimony, 1wt% Al-TCB seed alloy and 1wt% Al-B master alloy, and the balance is aluminum and unavoidable impurities;

[0053] (1) Material preparation: prepare the corresponding metal ingots or alloy intermediates according to the formula ratio;

[0054] (2) Alloy smelting: heat the furnace to 760°C and keep it warm, first put in some aluminum ingots, heat for 1 hour until the aluminum ingots are completely melted, heat to 800°C, add iron source and manganese source, stir for 20 minutes, add silicon source in 3 times, each time with an interval of 6 minutes, stir and keep warm for 40 minutes after the addition is completed, cool to 750°C, add zinc source, strontium source, lanthanum source, and ytterbium source, stir and keep warm for 45 minutes, cool to 730°C, add antimony source, stir and keep warm for 15 minutes, add 1wt% Al-B master alloy, stir and keep warm for 6 minutes, add 1wt% Al-TCB seed alloy and the remaining aluminum ingots, stir and keep warm for 25 minutes to obtain an alloy melt;

[0055] (3) Slag removal: Cool down to 720℃, add hexachloroethane refining agent for refining and slag removal, stir for 12 minutes, let stand for 5 minutes, scrape out the slag, and repeat 3 times;

[0056] (4) Degassing: Cool down to 700°C, use a four-tube degassing rake to blow argon into the alloy liquid, the argon outlet pressure is 0.5MPa, degas for 30 minutes, let it stand for 15 minutes, scrape out the slag, and obtain the alloy liquid;

[0057] (5) Vacuum die casting: The alloy liquid is subjected to vacuum die casting. The die casting process is set as follows: pouring temperature 680°C, air pressure <50mbar, injection force 330kN, injection time 3s, cooling time 2s, mold retention time 10s, mold temperature 150°C, to produce aluminum alloy materials for ultra-large size die castings.

[0058] Comparative Example 1

[0059] A preparation process of an aluminum alloy material for an oversized die casting, the preparation process of an aluminum alloy material for an oversized die casting comprising the following preparation steps:

[0060] The composition includes the following components by mass percentage: 0.8% iron, 0.40% manganese, 8% silicon, 1.95% zinc, 0.03% strontium, 0.3% lanthanum, 0.3% ytterbium, <0.03% copper, <0.05% magnesium, 0.2% antimony, 1wt% Al-TCB seed alloy and 1wt% Al-B master alloy, and the balance is aluminum and unavoidable impurities;

[0061] (1) Material preparation: prepare the corresponding metal ingots or alloy intermediates according to the formula ratio;

[0062] (2) Alloy smelting: heat the furnace to 755°C and keep it warm, first put in some aluminum ingots, heat for 1.2 hours until the aluminum ingots are completely melted, heat to 800°C, add iron source and manganese source, stir for 18 minutes, add silicon source in 3 times, each time with an interval of 6 minutes, stir and keep warm for 35 minutes after the addition is completed, cool to 750°C, add zinc source, strontium source, lanthanum source, and ytterbium source, stir and keep warm for 40 minutes, cool to 730°C, add antimony source, stir and keep warm for 15 minutes, add 1wt% Al-B master alloy, stir and keep warm for 6 minutes, add 1wt% Al-TCB seed alloy and the remaining aluminum ingots, stir and keep warm for 20 minutes to obtain an alloy melt;

[0063] (3) Slag removal: Cool down to 720℃, add hexachloroethane refining agent for refining and slag removal, stir for 11 minutes, let stand for 5 minutes, scrape out the slag, and repeat 3 times;

[0064] (4) Degassing: Cool down to 700°C, use a four-tube degassing rake to blow argon into the alloy liquid, the argon outlet pressure is 0.5MPa, degas for 30 minutes, let it stand for 15 minutes, scrape out the slag, and obtain the alloy liquid;

[0065] (5) Sand mold casting: When the alloy liquid is at 680°C, remove the scum on the surface, pour it into the sand mold, pass argon gas for 45 seconds, wait for it to cool and solidify naturally, then remove the sand mold to produce aluminum alloy material for super-large die castings.

[0066] Comparative Example 2

[0067] A preparation process of an aluminum alloy material for an oversized die casting, the preparation process of an aluminum alloy material for an oversized die casting comprising the following preparation steps:

[0068] The composition includes the following components by mass percentage: 0.8% iron, 0.40% manganese, 8% silicon, 1.95% zinc, 0.03% strontium, 0.3% lanthanum, 0.3% ytterbium, <0.03% copper, <0.05% magnesium, 1wt% Al-TCB seed alloy and 1wt% Al-B master alloy, and the balance is aluminum and unavoidable impurities;

[0069] (1) Material preparation: prepare the corresponding metal ingots or alloy intermediates according to the formula ratio;

[0070] (2) Alloy smelting: heat the furnace to 755°C and keep it warm, first put in some aluminum ingots, heat for 1.2 hours until the aluminum ingots are completely melted, heat to 800°C, add iron source and manganese source, stir for 18 minutes, add silicon source in 3 times, each time with an interval of 6 minutes, stir and keep warm for 35 minutes after the addition is completed, cool to 750°C, add zinc source, strontium source, lanthanum source, and ytterbium source, stir and keep warm for 40 minutes, cool to 730°C, add 1wt% Al-B master alloy, stir and keep warm for 6 minutes, add 1wt% Al-TCB seed alloy and the remaining aluminum ingots, stir and keep warm for 20 minutes, and obtain an alloy melt;

[0071] (3) Slag removal: Cool down to 720℃, add hexachloroethane refining agent for refining and slag removal, stir for 11 minutes, let stand for 5 minutes, scrape out the slag, and repeat 3 times;

[0072] (4) Degassing: Cool down to 700°C, use a four-tube degassing rake to blow argon into the alloy liquid, the argon outlet pressure is 0.5MPa, degas for 30 minutes, let it stand for 15 minutes, scrape out the slag, and obtain the alloy liquid;

[0073] (5) Vacuum die casting: The alloy liquid is subjected to vacuum die casting. The die casting process is set as follows: pouring temperature 680°C, air pressure <50mbar, injection force 330kN, injection time 3s, cooling time 2s, mold retention time 10s, mold temperature 150°C, to produce aluminum alloy materials for ultra-large size die castings.

[0074] Comparative Example 3

[0075] A preparation process of an aluminum alloy material for an oversized die casting, the preparation process of an aluminum alloy material for an oversized die casting comprising the following preparation steps:

[0076] In percentage by mass, it comprises the following components: 0.8% iron, 0.40% manganese, 8% silicon, 1.95% zinc, 0.03% strontium, 0.3% lanthanum, 0.3% ytterbium, <0.03% copper, <0.05% magnesium, 0.2% antimony, and the balance being aluminum and unavoidable impurities;

[0077] (1) Material preparation: prepare the corresponding metal ingots or alloy intermediates according to the formula ratio;

[0078] (2) Alloy smelting: Heat the furnace to 755°C and keep it warm. First, add some aluminum ingots and heat for 1.2 hours until the aluminum ingots are completely melted. Heat to 800°C, add iron source and manganese source, stir for 18 minutes, add silicon source in 3 times, each time with an interval of 6 minutes. After the addition is completed, stir and keep warm for 35 minutes. Cool down to 750°C, add zinc source, strontium source, lanthanum source and ytterbium source, stir and keep warm for 40 minutes, cool down to 730°C, add antimony source, stir and keep warm for 15 minutes, add the remaining aluminum ingots, stir and keep warm for 20 minutes to obtain alloy melt;

[0079] (3) Slag removal: Cool down to 720℃, add hexachloroethane refining agent for refining and slag removal, stir for 11 minutes, let stand for 5 minutes, scrape out the slag, and repeat 3 times;

[0080] (4) Degassing: Cool down to 700°C, use a four-tube degassing rake to blow argon into the alloy liquid, the argon outlet pressure is 0.5MPa, degas for 30 minutes, let it stand for 15 minutes, scrape out the slag, and obtain the alloy liquid;

[0081] (5) Vacuum die casting: The alloy liquid is subjected to vacuum die casting. The die casting process is set as follows: pouring temperature 680°C, air pressure <50mbar, injection force 330kN, injection time 3s, cooling time 2s, mold retention time 10s, mold temperature 150°C, to produce aluminum alloy materials for ultra-large size die castings.

[0082] Test Example 1

[0083] Mechanical properties test: The tensile strength, yield strength and elongation are tested to evaluate the mechanical properties of the aluminum alloy material for the prepared super-large size die castings. The specific test methods are as follows:

[0084] Tensile test: refer to GB / T 228.1-2021 for tensile performance test. The specimen length is 140mm, width is 18mm, gauge length is 40mm, thickness is 3mm, tensile speed is 3mm / min, test stress curve, calculate and record tensile strength, yield strength and elongation, and test 5 samples in each group and take the average value for recording.

[0085] The results are shown in Table 1.

[0086] Table 1

[0087] Tensile strength / MPa Yield strength / MPa Elongation / % Example 1 281.2 148.6 15.3 Example 2 287.5 152.3 17.5 Example 3 275.4 147.1 16.2 Comparative Example 1 183.5 87.5 5.3 Comparative Example 2 252.4 124.3 12.4 Comparative Example 3 233.8 109.6 10.9

[0088] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 1, it can be found that the aluminum alloy material for super-large-size die castings prepared by the present invention has good tensile strength, yield strength and elongation.

[0089] By comparison, the high cooling rate of vacuum die casting effectively improves the mechanical properties of the alloy, and the addition of antimony, Al-B master alloy and Al-TCB seed alloy also achieves good results, which has a good improvement on the mechanical properties.

[0090] Test Example 2

[0091] Thermal conductivity test: The thermal conductivity test is used to evaluate the thermal conductivity of the aluminum alloy material used for the prepared super-large size die castings. The specific test method is as follows:

[0092] Thermal conductivity test: Refer to GB / T 3651-2008 to test the thermal conductivity of aluminum alloy materials for super-large die castings. Test 5 samples in each group and take the average value for record.

[0093] The results are shown in Table 2.

[0094] Table 2

[0095] <![CDATA[Thermal conductivity / W·m -1 ·k -1 > <![CDATA[Thermal conductivity / W·m -1 ·k -1 > Example 1 171 Comparative Example 1 148 Example 2 176 Comparative Example 2 159 Example 3 169 Comparative Example 3 162

[0096] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 2, it can be found that the aluminum alloy material for super-large-size die castings prepared by the present invention has a higher thermal conductivity.

[0097] By comparison, the high cooling rate of vacuum die casting, the grain refinement effect of metal antimony, Al-B master alloy and Al-TCB seed alloy, and the modification and improvement effect of iron phase and silicon phase all increase the thermal conductivity of the alloy, making it have good application potential in electrical components that require heat dissipation.

[0098] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A process for preparing aluminum alloy materials for super-large size die castings, characterized in that: The method comprises the following preparation steps: (1) Material preparation: prepare corresponding metal ingots or alloy intermediates according to the formula ratio; (2) Alloy smelting: heating the furnace to 750-760°C and keeping the temperature, first adding part of the aluminum ingot, heating for 1-1.5 hours until the aluminum ingot is completely melted, heating to 800°C, adding the iron source and manganese source, stirring for 15-20 minutes, adding the silicon source in three times, each time with an interval of 5-6 minutes, stirring and keeping the temperature for 30-40 minutes after the addition is completed, cooling to 750°C, adding the zinc source, strontium source, lanthanum source, and ytterbium source, stirring and keeping the temperature for 40-45 minutes, cooling to 730°C, adding the antimony source, stirring and keeping the temperature for 10-15 minutes, adding 1wt% of Al-B master alloy, stirring and keeping the temperature for 5-6 minutes, adding 1wt% of Al-TCB seed alloy and the remaining aluminum ingot, stirring and keeping the temperature for 20-25 minutes, and obtaining an alloy melt; (3) Slag removal: Cool down to 720°C, add hexachloroethane refining agent for refining and slag removal, stir for 10-12 minutes, let stand for 5-6 minutes, scrape out the slag, and repeat 3 times; (4) Degassing: Cool down to 700°C, use a four-tube degassing rake to blow argon into the alloy liquid, the argon outlet pressure is 0.5 MPa, degas for 30 minutes, let it stand for 15 minutes, scrape out the scum, and obtain the alloy liquid; (5) Vacuum die casting: The alloy liquid is subjected to vacuum die casting. The die casting process is set as follows: pouring temperature 680°C, air pressure <50mbar, injection force 330kN, injection time 3s, cooling time 2s, mold retention time 10s, mold temperature 150°C, to obtain aluminum alloy materials for ultra-large die castings; The aluminum alloy material for super-large die castings includes the following components by mass percentage: 0.7-0.9% iron, 0.35-0.45% manganese, 7-9% silicon, 1.8-2.1% zinc, 0.02-0.05% strontium, 0.2-0.4% lanthanum, 0.2-0.4% ytterbium, <0.03% copper, <0.05% magnesium, 0.2% antimony, 1wt% Al-TCB seed alloy and 1wt% Al-B master alloy are added, and the balance is aluminum and unavoidable impurities; The mass ratio of iron to manganese is 2:1; The type of the Al-TCB seed alloy is AlTiCB.

2. The process for preparing an aluminum alloy material for super-large die castings according to claim 1, characterized in that: The mass percentage of impurities is less than 0.3wt%.

3. The process for preparing an aluminum alloy material for super-large size die castings according to claim 1, characterized in that: The aluminum ingot in step (2) is one or more of pure aluminum, electrolytic aluminum or recycled aluminum, the iron source is an aluminum-iron master alloy, the manganese source is electrolytic manganese or an aluminum-manganese master alloy, the silicon source is single crystal silicon or an aluminum-silicon master alloy, the zinc source is metallic zinc or an aluminum-zinc master alloy, the strontium source is an aluminum-strontium master alloy, the lanthanum source is an aluminum-lanthanum master alloy, the ytterbium source is an aluminum-ytterbium master alloy, and the antimony source is an aluminum-antimony master alloy.

4. The process for preparing an aluminum alloy material for super-large size die castings according to claim 1, characterized in that: In step (2), other alloy raw materials except the aluminum ingot are wrapped in aluminum foil and added to the furnace.

5. The process for preparing an aluminum alloy material for super-large size die castings according to claim 1, characterized in that: The mass of the partial aluminum ingot in step (2) accounts for 70-75% of the total mass of the aluminum ingot to be added, and the mass of the remaining aluminum ingot is the mass of the aluminum ingot remaining after deducting the mass of the aluminum ingot and aluminum foil already added.

6. The process for preparing an aluminum alloy material for super-large die castings according to claim 1, characterized in that: The hexachloroethane refining agent model in step (3) is TY-JL-1, and the added amount is 0.1-1% of the mass of the alloy melt.