Aluminum alloy for high-pressure casting and preparation method thereof

Abstract

The invention discloses an aluminum alloy for high-pressure casting and a preparation method of the aluminum alloy, and relates to the field of aluminum alloys. 2.5%-4.5% of Cu; 2 to 4 percent of Zn; 0.6%-1% of Mn; 0.6%-1% of Mg; 0 to 0.7% of Fe; 0 to 0.5 percent of Ni; 0 to 0.1 percent of Sn; 0 to 0.1 percent of Pb; 0 to 0.1 percent of Hg; 0 to 0.1 percent of Cd; and Al: the balance. The aluminum alloy has the effect of improving the tensile strength of the aluminum alloy.

Description

Technical Field

[0001] The invention relates to the field of aluminum alloys, and in particular to an aluminum alloy for high-pressure casting and a preparation method thereof. Background Art

[0002] With the development of modern industry, the demand for lightweight and high-performance alloys is increasing. Among them, aluminum alloys have attracted widespread attention due to their low density and high specific strength.

[0003] Aluminum alloy is an alloy with aluminum as the base element and one or more alloying elements added. Aluminum alloy has low density but relatively high strength, and has excellent electrical conductivity, thermal conductivity and corrosion resistance, which makes aluminum alloy materials widely used in the power industry.

[0004] It has become a common practice to improve the various mechanical properties of aluminum alloys by adding different trace elements, but achieving higher tensile strength remains a challenge. Summary of the invention

[0005] In order to improve the tensile strength of aluminum alloys, the present application provides an aluminum alloy for high pressure casting and a preparation method thereof.

[0006] In the first aspect, the present application provides an aluminum alloy for high pressure casting using the following technical solution: An aluminum alloy for high-pressure casting comprises the following percentage raw materials: Si: 9-10.5%; Cu: 2.5-4.5%; Zn: 2-4%; Mn: 0.6-1%; Mg: 0.6-1%; Fe: 0-0.7%; Ni: 0-0.5%; Sn: 0-0.1%; Pb: 0-0.1%; Hg: 0-0.1%; Cd: 0-0.1%; Al: balance.

[0007] By adopting the above technical scheme, silicon element can improve the fluidity of metal during hot extrusion of aluminum alloy and improve the production efficiency of aluminum alloy, iron element can reduce the crack tendency during casting, copper element can improve the strength and toughness of the alloy, zinc element and magnesium element can be evenly dispersed in the alloy to improve the strength and toughness of the alloy. This application improves the tensile strength of aluminum alloy while ensuring the strength of aluminum alloy by controlling the percentage of various elements in the aluminum alloy.

[0008] Preferably, the aluminum alloy also includes the following percentage raw materials: modified aluminum stearate 1-1.5%; sodium fluoride 0.1-0.8%; lubricant 0.5-1%; the modified aluminum stearate is made of the following raw materials: aluminum stearate, palmitic acid, ethanol, flax fiber, polypropylene.

[0009] By adopting the above technical scheme, modified aluminum stearate forms a super hydrophobic protective layer on the surface of aluminum alloy, sodium fluoride can prevent corrosion and weaving of aluminum alloy, and extend the shelf life of aluminum alloy, while the lubricant can reduce the direct contact between the mold and aluminum during the preparation process, reduce oxidation of the mold surface, and improve the surface quality of the aluminum alloy.

[0010] Preferably, the preparation method of the modified aluminum stearate is: 10-20 parts by weight of aluminum stearate, 2-6 parts by weight of palmitic acid and 20-60 parts by weight of ethanol are ultrasonically mixed, and then heated and stirred with 5-10 parts by weight of flax fiber and 3-9 parts by weight of polypropylene, filtered and then dried, and ground to obtain the modified aluminum stearate.

[0011] By adopting the above technical scheme, the present application mixes aluminum stearate, palmitic acid and ethanol and then adds flax fiber and polypropylene in the preparation process. Aluminum stearate and palmitic acid can form a hydrophobic surface treatment layer to enhance the surface properties of aluminum alloy and improve the corrosion resistance and wear resistance of aluminum alloy.

[0012] Preferably, the flax fiber is a modified flax fiber, and the preparation method of the modified flax fiber is: 10-20 parts by weight of flax fiber, 5-15 parts by weight of tris(hydroxymethyl)aminomethane) and 2-6 parts by weight of dopamine are mixed and stirred, and then 2-4 parts by weight of KH550 and 3-7 parts by weight of ferric chloride hexahydrate are added and stirred, and the modified flax fiber is obtained after drying.

[0013] By adopting the above technical scheme, the present application modifies the flax fiber, and KH550 can improve the interface compatibility between the flax fiber and polypropylene, improve the adhesion of aluminum stearate, improve the crystallization properties of the composite material treated with aluminum stearate, and thus improve the tensile strength properties of the aluminum alloy.

[0014] Preferably, the weight ratio of the flax fiber, tris(hydroxymethyl)aminomethane and ferric chloride hexahydrate is (1.6-1.8):1:(0.54-0.62).

[0015] By adopting the above technical scheme, when flax fiber, tris(hydroxymethyl)aminomethane and ferric chloride hexahydrate are in a specific weight ratio, the three work together, and the surface modification of flax fiber can enhance its combination with aluminum stearate and improve the performance of the composite material; tris(hydroxymethyl)aminomethane increases the reactivity of aluminum stearate; and ferric chloride hexahydrate increases the stability of aluminum stearate through the acidic environment generated by the hydrolysis reaction, thereby improving the mechanical properties and impact resistance of the aluminum alloy.

[0016] Preferably, the weight ratio of the aluminum stearate, palmitic acid, polypropylene and modified flax fiber is (2.4-2.8):(0.9-1.04):1:(1.1-1.4).

[0017] By adopting the above technical scheme, when aluminum stearate, palmitic acid, polypropylene and modified flax fiber are in a specific weight ratio, the modified flax fiber combined with polypropylene can improve the tensile properties of the aluminum alloy, and aluminum stearate forms a super hydrophobic protective coating on the surface of the aluminum alloy through palmitic acid. The carboxyl group in aluminum stearate reacts with the hydroxyl group in the modified flax fiber, so that the modified flax fiber has good compatibility with polypropylene, thereby improving the surface properties of the aluminum alloy.

[0018] Preferably, the mass ratio of the modified aluminum stearate, Al, Cu and Fe is (1.2-1.6):(155-156.6):(7.2-8.4):1.

[0019] By adopting the above technical scheme, when the modified aluminum stearate, Al, Cu and Fe are in a specific mass ratio, the amount of iron element is controlled, which can reduce the occurrence of cracks when casting aluminum alloy. If the iron element is too high, it is easy to weaken the extrusion performance of the aluminum alloy and cause surface defects of the aluminum alloy. The copper element can improve production efficiency and shorten the melting and casting time. The three together help to improve the tensile strength of the aluminum alloy.

[0020] Preferably, the lubricant includes one of molybdenum disulfide, graphite, and polytetrafluoroethylene.

[0021] By adopting the above technical solution and selecting a suitable lubricant, the friction between the metal and the extrusion cylinder wall, the piercing needle and the mold surface can be reduced, and the adhesion and wear of the tooling can be reduced.

[0022] In a second aspect, the present application provides a method for preparing an aluminum alloy for high pressure casting using the following technical solution: A method for preparing an aluminum alloy for high-pressure casting comprises the following steps: weighing raw materials in proportion, mixing and heating until molten, refining, degassing, deslagging, stirring, slagging, and die-casting and cooling to obtain the aluminum alloy.

[0023] By adopting the above technical scheme, the preparation method of the present application is relatively simple and efficient, and can directly adopt the traditional melting process for quantitative production. The operation difficulty is relatively low, which is convenient for realizing industrial mass production.

[0024] In summary, this application has the following beneficial technical effects: 1. Silicon can improve the fluidity of the metal during hot extrusion of aluminum alloy and improve the production efficiency of aluminum alloy. Iron can reduce the crack tendency during casting. Copper can improve the strength and toughness of the alloy. Zinc and magnesium can be evenly dispersed in the alloy to improve the strength and toughness of the alloy. This application improves the tensile strength of the aluminum alloy while ensuring the strength of the aluminum alloy by controlling the percentage of various elements in the aluminum alloy.

[0025] 2. Modified aluminum stearate forms a super hydrophobic protective layer on the surface of aluminum alloy, sodium fluoride can prevent aluminum alloy from corrosion and weaving, and extend the shelf life of aluminum alloy, while lubricant can reduce the direct contact between mold and aluminum during the preparation process, reduce the oxidation of the mold surface, and improve the surface quality of aluminum alloy.

[0026] 3. When the modified aluminum stearate, Al, Cu and Fe are in a specific mass ratio, controlling the amount of iron can reduce the occurrence of cracks when casting aluminum alloy. If the iron element is too high, it will easily weaken the extrusion performance of the aluminum alloy and cause surface defects of the aluminum alloy. The copper element can improve production efficiency and shorten the casting time. The three together help to improve the tensile strength of the aluminum alloy. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with embodiments and comparative examples. Example

[0028] Example 1 A method for preparing an aluminum alloy for high pressure casting comprises the following steps: Various raw materials are weighed in proportion and set aside for use. The raw materials are heated to a molten state at a temperature of 750°C to obtain a melt. The melt is refined at a temperature of 730°C, and nitrogen is introduced for degassing, deslagging, stirring, and slag removal. The die-casting process is carried out, the die-casting temperature is set to 680°C, and the die-casting machine speed is 2m / s. After being placed in the air for 24 hours, the heat treatment furnace is heated to 150°C and then kept warm. After the insulation is continued for 120 minutes, it is naturally cooled in the air to obtain an aluminum alloy.

[0029] The proportions of the raw materials are: Si: 9%; Cu: 2.5%; Zn: 2%; Mn: 0.6%; Mg: 0.6%; Fe: 0.1%; Ni: 0.1%; Sn: 0.1%; Pb: 0.1%; Hg: 0.1%; Cd: 0.1%; Al: 84.7%.

[0030] Example 2 A method for preparing an aluminum alloy for high-pressure casting, which differs from Example 1 in that the proportions of raw materials are different: Si: 10.5%; Cu: 4.5%; Zn: 4%; Mn: 1%; Mg: 1%; Fe: 0.7%; Ni: 0.5%; Sn: 0.1%; Pb: 0.1%; Hg: 0.1%; Cd: 0.1%; Al: 77.4%.

[0031] Example 3 A method for preparing an aluminum alloy for high-pressure casting, which differs from Example 1 in that the proportions of raw materials are different: Si: 10%; Cu: 3%; Zn: 3%; Mn: 0.8%; Mg: 0.8%; Fe: 0.4%; Ni: 0.3%; Sn: 0.1%; Pb: 0.1%; Hg: 0.1%; Cd: 0.1%; Al: 81.3%.

[0032] Example 4 A method for preparing an aluminum alloy for high pressure casting, which is different from Example 3 in that: modified aluminum stearate, sodium fluoride and lubricant are also added, the proportion of modified aluminum stearate is 1%, the proportion of sodium fluoride is 0.1%, and the proportion of lubricant is 0.5%; The preparation method of modified aluminum stearate is as follows: 10 kg of aluminum stearate, 2 kg of palmitic acid and 20 kg of ethanol are ultrasonically mixed for 30 minutes, and then heated and stirred with 5 kg of flax fiber and 3 kg of polypropylene in a water bath at a temperature of 60°C for 30 minutes, filtered and transferred to an oven, dried at a temperature of 100°C for 2 hours, and ground to obtain modified aluminum stearate.

[0033] Example 5 A method for preparing an aluminum alloy for high pressure casting, which is different from Example 3 in that: modified aluminum stearate, sodium fluoride and lubricant are also added, the proportion of modified aluminum stearate is 1.5%, the proportion of sodium fluoride is 0.8%, and the proportion of lubricant is 1%; The preparation method of modified aluminum stearate is as follows: 10 kg of aluminum stearate, 2 kg of palmitic acid and 20 kg of ethanol are ultrasonically mixed for 30 minutes, and then heated and stirred with 5 kg of flax fiber and 3 kg of polypropylene in a water bath at a temperature of 60°C for 30 minutes, filtered and transferred to an oven, dried at a temperature of 100°C for 2 hours, and ground to obtain modified aluminum stearate.

[0034] Example 6 A method for preparing an aluminum alloy for high-pressure casting, which is different from Example 5 in that: the preparation method of modified aluminum stearate is: 20kg of aluminum stearate, 6kg of palmitic acid and 60kg of ethanol are ultrasonically mixed for 30 minutes, and then heated and stirred with 10kg of flax fiber and 9kg of polypropylene in a water bath at a temperature of 60°C for 30 minutes, filtered and transferred to an oven, dried at a temperature of 100°C for 2 hours, and ground to obtain modified aluminum stearate.

[0035] Example 7 A method for preparing an aluminum alloy for high-pressure casting, which is different from Example 6 in that: when preparing modified aluminum stearate, an equal amount of flax fiber is replaced by modified flax fiber, and the preparation method of the modified flax fiber is as follows: 10 kg of flax fiber is mixed with 5 kg of tris(hydroxymethyl)aminomethane and 2 kg of dopamine and stirred for 5 minutes, then 2 kg of KH550 and 3 kg of ferric chloride hexahydrate are added and stirred for 10 minutes, and the mixture is transferred to an oven and dried at a temperature of 100° C. for 12 hours to obtain the modified flax fiber.

[0036] Example 8 A method for preparing an aluminum alloy for high-pressure casting, which is different from Example 6 in that: when preparing modified aluminum stearate, an equal amount of flax fiber is replaced by modified flax fiber, and the preparation method of the modified flax fiber is as follows: 20 kg of flax fiber is mixed with 15 kg of tris(hydroxymethyl)aminomethane) and 6 kg of dopamine and stirred for 5 minutes, then 4 kg of KH550 and 7 kg of ferric chloride hexahydrate are added and stirred for 10 minutes, and the mixture is transferred to an oven and dried at a temperature of 100° C. for 12 hours to obtain the modified flax fiber.

[0037] Example 9 A method for preparing an aluminum alloy for high-pressure casting, which is different from Example 8 in that: the input amount of flax fiber is 16 kg, the input amount of tris(hydroxymethyl)aminomethane is 10 kg, and the input amount of ferric chloride hexahydrate is 5.4 kg.

[0038] Example 10 A method for preparing an aluminum alloy for high-pressure casting, which is different from Example 8 in that: the input amount of flax fiber is 18 kg, the input amount of tris(hydroxymethyl)aminomethane is 10 kg, and the input amount of ferric chloride hexahydrate is 6.2 kg.

[0039] Embodiment 11 A method for preparing an aluminum alloy for high-pressure casting, which is different from Example 10 in that the input amount of aluminum stearate is 12 kg, the input amount of palmitic acid is 4.5 kg, the input amount of polypropylene is 5 kg, and the input amount of modified flax fiber is 5.5 kg.

[0040] Example 12 A method for preparing an aluminum alloy for high-pressure casting, which is different from Example 10 in that the input amount of aluminum stearate is 14 kg, the input amount of palmitic acid is 5.2 kg, the input amount of polypropylene is 5 kg, and the input amount of modified flax fiber is 7 kg.

[0041] Example 13 A method for preparing an aluminum alloy for high-pressure casting, which differs from Example 12 in that the input amount of modified aluminum stearate is 0.6%, the input amount of Al is 78.3%, the input amount of Cu is 3.6%, and the input amount of Fe is 0.5%.

[0042] Embodiment 14 A method for preparing an aluminum alloy for high-pressure casting, which is different from Example 10 in that the input amount of modified aluminum stearate is 0.8%, the input amount of Al is 77.5%, the input amount of Cu is 4.2%, and the input amount of Fe is 0.5%.

[0043] Comparative Example Comparative Example 1 A method for preparing an aluminum alloy for high pressure casting, which is different from Example 3 in that the input amount of Cu is 1.2%, the input amount of Fe is 0.5%, and the input amount of Al is 83%.

[0044] Comparative Example 2 A method for preparing an aluminum alloy for high pressure casting, which is different from Example 3 in that the input amount of Cu is 7.2%, the input amount of Fe is 2.4%, and the input amount of Al is 75.1%.

[0045] Comparative Example 3 A method for preparing an aluminum alloy for high pressure casting, which is different from Example 3 in that the input amount of Cu is 3%, the input amount of Fe is 2.4%, and the input amount of Al is 79.3%.

[0046] The ingredients and proportions of the embodiments and comparative examples are shown in Table 1: Performance testing: Tensile strength test method: The aluminum alloys prepared in Examples 1-14 and Comparative Examples 1-3 were tested using a universal material testing machine according to the test method of GB / T 228.1-2010.

[0047] Yield strength test method: The aluminum alloys prepared in Examples 1-14 and Comparative Examples 1-3 were tested using a universal material testing machine according to the test method of GB / T 228.1-2010.

[0048] Elongation test method: The aluminum alloys prepared in Examples 1-14 and Comparative Examples 1-3 were tested using a universal material testing machine according to the test method of GB / T 228.1-2010. Tensile strength MPa Yield strength MPa Elongation % Example 1 462.2 495.6 11.6 Example 2 462.6 495.4 11.5 Example 3 463.1 495.7 11.7 Example 4 480.3 495.9 12.3 Example 5 480.6 496.2 12.2 Example 6 481.1 496.3 12.2 Example 7 485.5 498.4 12.3 Example 8 485.9 498.5 12.5 Example 9 498.6 500.7 12.5 Example 10 498.2 500.6 12.6 Embodiment 11 504.3 502.6 12.5 Example 12 504.1 502.5 12.5 Example 13 510.9 503.4 12.6 Embodiment 14 511.3 503.6 12.6 Comparative Example 1 445.5 455.1 8.5 Comparative Example 2 433.8 450.6 8.9 Comparative Example 3 446.2 450.4 9.1

[0049] According to the data comparison of Examples 1-3 and Comparative Examples 1-4, it can be obtained that the silicon element can improve the fluidity of the metal during hot extrusion of the aluminum alloy and improve the production efficiency of the aluminum alloy, the iron element can reduce the crack tendency during casting, the copper element can improve the strength and toughness of the alloy, and the zinc element and the magnesium element can be evenly dispersed in the alloy to improve the strength and toughness of the alloy. The present application improves the tensile strength of the aluminum alloy while ensuring the strength of the aluminum alloy by controlling the percentage of various elements in the aluminum alloy.

[0050] According to the data comparison of Examples 3-6, modified aluminum stearate forms a super hydrophobic protective layer on the surface of aluminum alloy, sodium fluoride can prevent corrosion and weaving of aluminum alloy, and extend the shelf life of aluminum alloy, while lubricant can reduce the direct contact between mold and aluminum during the preparation process, reduce oxidation of the mold surface, and improve the surface quality of aluminum alloy.

[0051] According to the data comparison of Examples 6-8, the present application can improve the interfacial compatibility between flax fiber and polypropylene, improve the adhesion of aluminum stearate, improve the crystallization properties of the composite material treated with aluminum stearate, and thus improve the tensile strength properties of the aluminum alloy by modifying the flax fiber.

[0052] According to the data comparison of Examples 8-10, it can be obtained that when flax fiber, tris(hydroxymethyl)aminomethane and ferric chloride hexahydrate are in a specific weight ratio, the three work together, and the surface modification of flax fiber can enhance its combination with aluminum stearate and improve the performance of the composite material; tris(hydroxymethyl)aminomethane increases the reactivity of aluminum stearate; and ferric chloride hexahydrate increases the stability of aluminum stearate through the acidic environment generated by the hydrolysis reaction, thereby improving the mechanical properties and impact resistance of the aluminum alloy.

[0053] According to the data comparison of Examples 10-12, when aluminum stearate, palmitic acid, polypropylene and modified flax fiber are in a specific weight ratio, the modified flax fiber combined with polypropylene can improve the tensile properties of the aluminum alloy, and aluminum stearate forms a super hydrophobic protective coating on the surface of the aluminum alloy through palmitic acid. The carboxyl group in aluminum stearate reacts with the hydroxyl group in the modified flax fiber, so that the modified flax fiber has good compatibility with polypropylene, thereby improving the surface properties of the aluminum alloy.

[0054] According to the data comparison of Examples 12-14, when the modified aluminum stearate, Al, Cu and Fe are in a specific mass ratio, controlling the amount of iron element can reduce the occurrence of cracks when casting aluminum alloy. If the iron element is too high, it is easy to weaken the extrusion performance of the aluminum alloy and cause surface defects of the aluminum alloy. The copper element can improve production efficiency and shorten the melting and casting time. The three together help to improve the tensile strength of the aluminum alloy.

[0055] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An aluminum alloy for high pressure casting, characterized in that: The raw materials include the following percentages: Si: 9-10.5%; Cu: 2.5-4.5%; Zn: 2-4%; Mn: 0.6-1%; Mg: 0.6-1%; Fe: 0-0.7%; Ni: 0-0.5%; Sn: 0-0.1%; Pb: 0-0.1%; Hg: 0-0.1%; Cd: 0-0.1%; Al: margin.

2. The aluminum alloy for high pressure casting according to claim 1, characterized in that: The aluminum alloy also includes the following percentage raw materials: 1-1.5% modified aluminum stearate; 0.1-0.8% sodium fluoride; 0.5-1% lubricant; the modified aluminum stearate is made of the following raw materials: aluminum stearate, palmitic acid, ethanol, flax fiber, and polypropylene.

3. The aluminum alloy for high pressure casting according to claim 2, characterized in that: The preparation method of the modified aluminum stearate is as follows: 10-20 parts by weight of aluminum stearate, 2-6 parts by weight of palmitic acid and 20-60 parts by weight of ethanol are ultrasonically mixed, and then heated and stirred with 5-10 parts by weight of flax fiber and 3-9 parts by weight of polypropylene, filtered, dried, and ground to obtain the modified aluminum stearate.

4. The aluminum alloy for high pressure casting according to claim 3, characterized in that: The flax fiber is a modified flax fiber. The preparation method of the modified flax fiber is as follows: 10-20 parts by weight of flax fiber, 5-15 parts by weight of tris(hydroxymethyl)aminomethane) and 2-6 parts by weight of dopamine are mixed and stirred, and then 2-4 parts by weight of KH550 and 3-7 parts by weight of ferric chloride hexahydrate are added and mixed and stirred, and the modified flax fiber is obtained after drying.

5. The aluminum alloy for high pressure casting according to claim 4, characterized in that: The weight ratio of the flax fiber, tris(hydroxymethyl)aminomethane and ferric chloride hexahydrate is (1.6-1.8):1:(0.54-0.62).

6. The aluminum alloy for high pressure casting according to claim 4, characterized in that: The weight ratio of the aluminum stearate, palmitic acid, polypropylene and modified flax fiber is (2.4-2.8): (0.9-1.04): 1: (1.1-1.4).

7. The aluminum alloy for high pressure casting according to claim 3, characterized in that: The mass ratio of the modified aluminum stearate, Al, Cu and Fe is (1.2-1.6):(155-156.6):(7.2-8.4):

1.

8. The aluminum alloy for high pressure casting according to claim 2, characterized in that: The lubricant includes one of molybdenum disulfide, graphite and polytetrafluoroethylene.

9. A method for preparing an aluminum alloy for high pressure casting, characterized in that: The method for preparing the aluminum alloy for high-pressure casting as claimed in any one of claims 1 to 8 comprises the following steps: weighing raw materials in proportion, mixing and heating until molten, refining, degassing, deslagging, stirring, and slagging, and then die-casting and cooling to obtain the aluminum alloy.

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