CN113278831B - Method for preparing regenerated ADC12 aluminum alloy from scrap aluminum - Google Patents

Abstract

A method for preparing regenerated ADC12 aluminum alloy from scrap aluminum comprises the following steps: heating and smelting the waste aluminum scraps by using a vacuum high-frequency induction electromagnetic induction furnace, fully melting, and introducing argon for degassing; cooling the melt to 730 ℃, adding Al-30RE, Al-10Mn and Al-10Cr for refining and modification, stirring by a graphite rod, keeping the temperature, slagging off and filtering; adding intermediate alloy components of industrial pure Al and Al-30Si for adjustment, uniformly stirring after melting, blowing nitrogen, and standing to obtain regenerated aluminum alloy; the invention converts the impurities which are difficult to remove into a strengthening phase and uniformly distributes the strengthening phase on the matrix; meanwhile, the coarse acicular Fe-rich phase is effectively crushed, and the fracture influence of the Fe-rich phase on the matrix is eliminated; and the flaky eutectic Si phase is refined into a short rod shape or a fibrous shape, so that the fracture influence on the matrix is weakened. The mechanical property of the aluminum alloy can be effectively improved; the preparation method is simple, has low cost and is beneficial to industrialization.

Description

A method for preparing recycled ADC12 aluminum alloy from waste miscellaneous aluminum

technical field

The invention relates to the technical field of metal materials, in particular to a recycled aluminum alloy formulation and a preparation method thereof.

Background technique

Aluminum products for vehicles are often combined with Fe and Cu-based components or assembled with Fe-based connectors. These recycled aluminum products are often packaged and sent to aluminum processing enterprises without distinction. Therefore, a thick needle-like iron-rich phase will be generated during the solidification process, which will split the aluminum alloy matrix and reduce the mechanical properties of the aluminum alloy. The content of Fe and Cu in the secondary aluminum alloy seriously exceeds the national standard. In addition, the content of impurity elements such as Mg, Zn, and Ni is also high. At the same time, ADC12 has practical problems such as low strength, poor plasticity, and general machinability, which makes it difficult to meet the requirements of high-strength parts. More importantly, due to Non-aluminum elements are brought in in large quantities, and their mechanical properties are far lower than those of primary aluminum alloy products, so it is difficult to maintain the technology of secondary aluminum alloys. The content of Fe and Cu in the secondary aluminum is significantly too high, and the Fe content is too high, and the needle-like Fe-rich phase is prone to appear in the alloy. This structure will split the matrix and reduce the mechanical properties of the alloy. This structure will also make the alloy. The fluidity decreases, the hot cracking property increases, and the corrosion resistance decreases. At the same time, ADC12 itself contains a certain amount of Cu, but its content seriously exceeds the national standard, and the Cu content is too high, which will also increase the hot cracking tendency of the alloy. That is, Fe and Cu are the main harmful elements that cause hot cracking defects in aluminum alloys. Therefore, in the manufacturing process, this kind of secondary aluminum alloy has a great tendency of hot cracking, the production yield is low, and the manufacturing cost is high. The traditional recycling of waste aluminum focuses on reducing the content of impurity elements in the aluminum melt. However, due to the late start of my country's recycled aluminum industry and no large-scale formation, the smelting technology and equipment are relatively backward, which makes the elements of recycled aluminum products complex. Usually, there are still many impurities that are difficult to remove after treatment, so most of them can only be downgraded.

The Chinese invention patent with the public number CN108998675A discloses the application of rare earths in the regeneration of waste aluminum, only adding rare earth elements after simple crushing, magnetic separation, etc., but this method cannot solve the residual problem of impurities such as Fe and Cu, so It is difficult to achieve the use of recycled aluminum for grade preservation.

Patent No. CN103643088A discloses a modifier for ADC12 aluminum alloy and a modification method thereof. It refines α-Al dendrites and improves the morphology and size of the eutectic Si phase through Ti, B and RE, thereby improving the mechanical properties of the alloy.

Patent No. CN110453102A discloses a composite modifier for ADC12 aluminum alloy and a preparation method thereof. It refines the morphology and size of α-Al dendrites and eutectic silicon phases through Te and rare earth Yb, thereby improving the mechanical properties and casting properties of ADC12.

To sum up, it can be seen that most of the existing technologies only introduce 1-2 rare earth elements, or simply introduce Ti and B to reduce the Fe content of the aluminum alloy melt, and pay less attention to the compounding of various rare earths, Mn and Cr on the aluminum alloy melt. improvement. The problems existing in the prior art cannot be effectively solved.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for preparing regenerated ADC12 aluminum alloy from waste miscellaneous aluminum, which can optimize the prepared aluminum alloy structure, and convert difficult-to-remove impurities such as Fe, Mg, Zn, and Ti in the alloy into a strengthening phase, It can also effectively crush the needle-like Fe-rich phase in the aluminum alloy to make it short rod-like, and can also refine the eutectic Si phase in the aluminum alloy into a network structure or fiber structure, and evenly distribute it in the matrix. At the same time, it also has the functions of purifying the melt and degassing, so that the number and size of pinholes on the alloy are significantly reduced.

The present invention is achieved through the following technical solutions.

A method for preparing regenerated ADC12 aluminum alloy from waste miscellaneous aluminum according to the present invention includes the following steps.

(1) Raw material smelting: heat and smelt the waste miscellaneous aluminum alloy in a vacuum high-frequency induction electromagnetic induction furnace.

(2) Refining and alloy composition adjustment: The molten aluminum alloy scrap melted in step (1) is cooled to 730 °C, and Al-30RE, Al-10Mn, and Al-10Cr are added to it for refining and metamorphism, and stirred with a graphite rod for 1 ～2min, hold the slag for 20min, then filter the slag, where RE is the mixed rare earth of La, Ce and Y; then add industrial pure Al and Al-30Si master alloy according to the mass percentage to adjust the composition, and wait until the master alloy is completely melted After stirring evenly, nitrogen was blown in again, the time was controlled at 5 min, and after standing for 20 to 30 min, a secondary aluminum alloy with adjusted composition was obtained.

(3) Casting: pouring the aluminum alloy solution obtained in step (2) into a mold, and cooling to room temperature to obtain an ingot.

The alloy composition adjustment described in step (2) is based on the composition of the prepared secondary aluminum alloy in mass percentage: Si: 9.6-12 wt.%, Cu: 1.5-3.5 wt.%, La: 0.01-1.0 wt.% %, Ce: 0.01-1.0 wt.%, Y: 0.01-1.0 wt.%, Mn: 0.01-0.2 wt.%, Cr: 0.01-0.2 wt.%, and impurities are controlled at: Fe<1.3wt.%, Mg<0.3wt.%, Zn<1.0wt.%, Ti:<0.2wt.%, the balance is Al, wherein the total amount of rare earth elements La, Ce and Y does not exceed 1 wt.%.

Preferably, in terms of the components in mass percentage of the prepared secondary aluminum alloy: Si: 9.6-12 wt.%, Cu: 1.5-3.5 wt.%, La: 0.01-0.5 wt.%, Ce: 0.01-0.5 wt.% .%, Y: 0.01-0.5 wt.%, Mn: 0.01-0.15 wt.%, Cr: 0.01-0.15 wt.%, of which impurities are controlled at: Fe<1.0 wt.%, Mg<0.25wt.%, Zn <0.8 wt.%, Ti: <0.15 wt.%, the balance is Al, and the total amount of rare earth elements La, Ce and Y does not exceed 1 wt.%.

Further, the pouring temperature range described in step (3) of the present invention is: 690-700 °C.

Further, the preheating temperature of the mold described in step (3) of the present invention is 200-250°C.

The present invention is based on the following theoretical foundations and principles. Fe, Mg, Zn, Ti are the most common impurity elements in the secondary aluminum refining process. For the conversion of Fe: by adding RE, Mn and Cr to the aluminum melt, Fe is easy to form (Fe, Mn)Al ₆ , (Cr, Fe)Al ₇ , FeRESiAl and other phases, thereby reducing the Fe impurity elements in the aluminum matrix. The solid solubility in the alloy has a certain strengthening effect on the alloy, and can also improve the toughness of the alloy and reduce the susceptibility to stress corrosion cracking. At the same time, Mn and Cr can break the long needle-like iron-rich phase to form a short rod-like or Chinese character-like shape; for the transformation of Mg: on the one hand, Mg can generate Mg ₂ Si strengthening phase in aluminum alloy, improve the tensile strength and hardness of the alloy, On the other hand, Mg can also generate Mg ₅ Al ₈ compound and precipitate uniformly, improving the corrosion resistance and welding performance of the alloy. More importantly, RE combines with Al in the regenerated aluminum melt to generate crystal nuclei such as La ₃ Al ₁₁ , Al ₃ Ce Al ₃ Y, etc., to achieve the effect of refining grains and thereby increase its mechanical properties; the present invention aggregates It is used to convert non-aluminum elements into endogenous precipitation phases, that is, by introducing rare earth and other elements, the impurities that are difficult to remove in the recycled aluminum melt are converted into fine and dispersed reinforcement phases, thereby improving the purity and performance of recycled aluminum. The grade-preserving regeneration of scrap aluminum solves the problems existing in the prior art.

Beneficial effects of the present invention: (1) The formula of the present invention can convert impurities that are difficult to remove in the regenerated ADC12 aluminum alloy into a strengthening phase, and at the same time, La, Ce and Y rare earth elements can effectively break the coarse needle-shaped Fe-rich phase, and at the same time, it has Purification of the melt, degassing, etc. At the same time, the combination of Mn and Cr makes the thick needle-like Fe-rich phase form Chinese characters, blocks and fishbone shapes. Eliminate the effect of Fe-rich relative to the matrix, thereby improving the mechanical properties of the alloy; (2) The regenerated ADC12 aluminum alloy prepared by the invention has a uniformly distributed strengthening phase, and helps to refine the eutectic Si phase, which can effectively improve the aluminum alloy. The mechanical properties of the alloy; (3) the preparation method of the present invention is simple, and the preparation method adopts a die-casting molding process, which has low cost and is beneficial to industrialization.

Description of drawings

Figure 1 is a microstructure photo of the ADC12 aluminum alloy in Comparative Example 1, wherein Figure a is a low magnification microstructure figure; Figure b is a high magnification microstructure figure.

FIG. 2 is a photo of the microstructure of the ADC12 aluminum alloy after modification in Example 3, wherein, Figure a is a low-magnification microstructure; Figure b is a high-magnification microstructure.

Fig. 3 is a microstructure photograph of the ADC12 aluminum alloy after modification in Example 4, wherein, Fig. a is a low magnification microstructure image; Fig. b is a high magnification microstructure image.

Detailed ways

The present invention will be further described below through specific examples and accompanying drawings. The following examples are all implemented on the premise of the technical solutions of the present invention, and provide detailed embodiments and specific operation processes, but the protection scope of the present invention is not limited to The following examples.

In the embodiment of the present invention, ADC12 waste miscellaneous aluminum alloy is selected as the raw material, subjected to smelting, casting, and homogenization treatment, and the microstructure and properties are tested as a comparative example. It should be noted that the purpose of the comparative example is only to better understand the technology of the present invention. Features and Benefits.

Comparative Example 1.

In this comparative example, ADC12 automobile scrap aluminum is used as the raw material. After simple sorting and packaging, it is put into smelting aluminum for smelting, and then cast and formed, and homogenized to obtain recycled aluminum alloy ingots. The composition was measured directly from the melt. The composition of the alloy and its mass percentage were: Si: 10.99 wt.%, Cu: 3.72 wt.%, Mn: 0.04%, Cr: 0.02%, Fe: 0.72%, Mg: 0.32 %, Zn: 0.68%, Ti: 0.24%, and the balance is Al.

The preparation method of the secondary aluminum alloy described in this comparative example, the preparation process and its parameters are as follows.

(1) Smelting of waste and miscellaneous aluminum alloys: ADC12 automobile scrap aluminum products are weighed, smelted, and then melt refined. A slag remover and a refining agent were added successively to refine and remove the slag, and the treatment temperature was controlled to be 730 °C, and after treatment, it was left to stand for 30 minutes to obtain an ADC12 regenerated aluminum alloy melt.

(2) Casting: The aluminum melt is poured into an ordinary metal mold for casting, and the mold preheating temperature is 200-300 °C.

The microstructure of the metallographic sample prepared by the ingot of Comparative Example 1 of casting molding was observed, and then the mechanical properties were tested. The tensile mechanical properties at room temperature were: tensile strength 153 MPa; elongation at break 1.2%.

Example 1. Al-10.22Si-3.0Cu-0.05La-0.05Ce-0.05Y-0.05Mn-0.05Cr (wt.%) secondary aluminum alloy and its preparation.

The preparation method described in this embodiment specifically includes the following steps.

(1) Raw material smelting: The ADC12 recycled aluminum obtained in Comparative Example 1 was weighed, and then heated and smelted in a vacuum high-frequency induction electromagnetic induction furnace. The smelting temperature was controlled at 760 °C to fully melt, and then argon was introduced for degassing.

(2) Refining and alloy composition adjustment: After the secondary aluminum alloy melt melted in step (1) is cooled to 730 °C, Al-30RE, Al-30Mn, and Al-20Cr are added to it for refining and metamorphism, and the slag is removed after holding for 20 min. , filter, where RE is the mixed rare earth of La, Ce and Y; then according to the composition according to the mass percentage, add industrial pure Al, Al-30Si master alloy to adjust the composition, after the master alloy is all melted, stir evenly, and then introduce nitrogen, The time was controlled at 5 min, and the secondary aluminum alloy with adjusted composition was obtained after standing for 30 min.

(3) Casting: first preheat the mold at 200 °C for 10 min, then cool down the aluminum alloy melt obtained in step (2) to 690 °C, pour the aluminum alloy solution into the mold, and cool it to room temperature to obtain an ingot .

The alloy composition in step (2) is adjusted according to the mass percentage of the prepared secondary aluminum alloy: Si: 10.22 wt.%, Cu: 3.0 wt.%, La: 0.05 wt.%, Ce: 0.05 wt.%. %, Y: 0.05 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, and the balance is Al and impurities such as Fe, Mg, Zn, and Ti. Among them, it was found that: Fe: 0.62%, Mg: 0.28%, Zn: 0.52%, Ti: 0.19%, and with (Fe, Mn)Al ₆ , (Cr, Fe)Al ₇ , FeRESiAl, Mg ₂ Si, MgZn ₂ , TiAl ₂ and other forms exist.

The room temperature tensile mechanical properties of the high-quality recycled aluminum alloy obtained in this embodiment are: tensile strength of 210 MPa; elongation at break of 2.7%.

Example 2. Al-9.9Si-2.72Cu-0.1La-0.1Ce-0.1Y-0.05Mn-0.05Cr (wt.%) secondary aluminum alloy and its preparation.

The preparation method described in this embodiment specifically includes the following steps.

(1) Raw material smelting: The ADC12 recycled aluminum obtained in Comparative Example 1 was weighed, and then heated and smelted in a vacuum high-frequency induction electromagnetic induction furnace. The smelting temperature was controlled at 760 °C to fully melt, and then argon was introduced for degassing.

(2) Refining and alloy composition adjustment: After the secondary aluminum alloy melt melted in step (1) is cooled to 730 °C, Al-30RE, Al-30Mn, and Al-20Cr are added to it for refining and metamorphism, and the slag is removed after holding for 20 min. , filter, where RE is the mixed rare earth of La, Ce, Y; then according to the composition according to the mass percentage, add industrial pure Al, Al-30Si master alloy to adjust the composition, after the master alloy is all melted, stir evenly, and then introduce nitrogen, The time was controlled at 5 min, and the secondary aluminum alloy with adjusted composition was obtained after standing for 30 min.

(3) Casting: first preheat the mold at 200 °C for 10 min, then cool down the aluminum alloy melt obtained in step (2) to 690 °C, pour the aluminum alloy solution into the mold, and cool it to room temperature to obtain an ingot.

The alloy composition in step (2) is adjusted according to the mass percentage of the prepared secondary aluminum alloy: Si: 9.9 wt.%, Cu: 2.72 wt.%, La: 0.1 wt.%, Ce: 0.1 wt.% %, Y: 0.1 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, and the balance is Al and impurities such as Fe, Mg, Zn, Ti, etc. Among them, it was found that: Fe: 0.58%, Mg: 0.24%, Zn: 0.45%, Ti: 0.15%, and with (Fe, Mn)Al ₆ , (Cr, Fe)Al ₇ , FeRESiAl, Mg ₂ Si, MgZn ₂ , TiAl ₂ and other forms exist.

The room temperature tensile mechanical properties of the high-quality recycled aluminum alloy obtained in this embodiment are: tensile strength of 220 MPa; elongation at break of 3.2%.

Comparative Example 2.

In this comparative example, ADC12 automobile scrap aluminum is used as the raw material. After simple sorting and packaging, it is put into smelting aluminum for smelting, and then cast and formed, and homogenized to obtain recycled aluminum alloy ingots. The composition was measured directly from the melt. The composition of the alloy and its mass percentage were: Si: 10.54 wt.%, Cu: 3.32 wt.%, Mn: 0.06%, Cr: 0.03%, Fe: 0.76%, Mg: 0.28 %, Zn: 0.56%, Ti: 0.19%, and the balance is Al.

The preparation method of the secondary aluminum alloy described in this comparative example, the preparation process and its parameters are as follows.

(1) Smelting of waste and miscellaneous aluminum alloys: ADC12 automobile scrap aluminum products are weighed, smelted, and then melt refined. A slag remover and a refining agent were added successively to refine and remove the slag, and the treatment temperature was controlled to be 730 °C, and after treatment, it was left to stand for 30 minutes to obtain an ADC12 regenerated aluminum alloy melt.

(2) Casting: The aluminum melt is poured into an ordinary metal mold for casting, and the mold preheating temperature is 200-300 °C.

The microstructure of the metallographic sample prepared from the ingot of Comparative Example 2, which was cast and formed, was observed, and then the mechanical properties were tested. The tensile mechanical properties at room temperature were: tensile strength 149 MPa; elongation at break 1.2%.

Example 3. Al-10.23Si-3.1Cu-0.15La-0.15Ce-0.15Y-0.08Mn-0.08Cr (wt.%) secondary aluminum alloy and its preparation.

The preparation method described in this embodiment specifically includes the following steps.

(1) Raw material smelting: The ADC12 recycled aluminum obtained in Comparative Example 2 was weighed, and then heated and smelted in a vacuum high-frequency induction electromagnetic induction furnace.

(2) Refining and alloy composition adjustment: After the secondary aluminum alloy melt melted in step (1) is cooled to 730 °C, Al-30RE, Al-30Mn, and Al-20Cr are added to it for refining and metamorphism, and the slag is removed after holding for 20 min. , filter, where RE is the mixed rare earth of La, Ce, Y; then according to the composition according to the mass percentage, add industrial pure Al, Al-30Si master alloy to adjust the composition, after the master alloy is all melted, stir evenly, and then introduce nitrogen, The time was controlled at 5min, and after standing for 20min, the secondary aluminum alloy with adjusted composition was obtained.

(3) Casting: first preheat the mold at 200 °C for 10 min, then cool down the aluminum alloy melt obtained in step (2) to 690 °C, pour the aluminum alloy solution into the mold, and cool it to room temperature to obtain an ingot .

The alloy composition in step (2) is adjusted according to the mass percentage of the prepared secondary aluminum alloy: Si: 10.23 wt.%, Cu: 3.1 wt.%, La: 0.15 wt.%, Ce: 0.15 wt.%. %, Y: 0.15 wt.%, Mn: 0.08 wt.%, Cr: 0.08 wt.%, and the balance is Al and impurities such as Fe, Mg, Zn, and Ti. Among them, it was found that: Fe: 0.62%, Mg: 0.22%, Zn: 0.42%, Ti: 0.13%, and with (Fe, Mn)Al ₆ , (Cr, Fe)Al ₇ , FeRESiAl, Mg ₂ Si, MgZn ₂ , TiAl ₂ and other forms exist.

The room temperature tensile mechanical properties of the high-quality recycled aluminum alloy obtained in this embodiment are: tensile strength of 226 MPa; elongation at break of 3.4%.

Example 4. Al-9.9Si-2.8Cu-0.3La-0.2Ce-0.3Y-0.1Mn-0.1Cr (wt.%) secondary aluminum alloy and its preparation.

The preparation method described in this embodiment specifically includes the following steps.

(1) Raw material smelting: The ADC12 recycled aluminum obtained in Comparative Example 1 was weighed, and then heated and smelted in a vacuum high-frequency induction electromagnetic induction furnace. The smelting temperature was controlled at 760 °C to fully melt, and then argon was introduced for degassing.

(2) Refining and alloy composition adjustment, after the secondary aluminum alloy melt melted in step (1) is cooled to 730 °C, Al-30RE, Al-30Mn, and Al-20Cr are added to it for refining and deterioration, and the slag is removed after holding for 20 min. , filter, where RE is the mixed rare earth of La, Ce, Y; then according to the composition according to the mass percentage, add industrial pure Al, Al-30Si master alloy to adjust the composition, after the master alloy is all melted, stir evenly, and then introduce nitrogen, The time was controlled at 5 min, and the secondary aluminum alloy with adjusted composition was obtained after standing for 30 min.

(3) Casting: first preheat the mold at 200 °C for 10 min, then cool down the aluminum alloy melt obtained in step (2) to 690 °C, pour the aluminum alloy solution into the mold, and cool it to room temperature to obtain an ingot .

The alloy composition in step (2) is adjusted according to the mass percentage of the prepared secondary aluminum alloy: Si: 9.9 wt.%, Cu: 2.8 wt.%, La: 0.3 wt.%, Ce: 0.2 wt.% %, Y: 0.3 wt. %, Mn: 0.1 wt. %, Cr: 0.1 wt. %, and the balance is impurities such as Al and Fe, Mg, Zn, and Ti. Among them, it was measured: Fe: 0.53%, Mg: 0.18%, Zn: 0.36%, Ti: 0.1%, and with (Fe, Mn)Al ₆ , (Cr, Fe)Al ₇ , FeRESiAl, Mg ₂ Si, MgZn ₂ , TiAl ₂ and other forms exist.

The room temperature tensile mechanical properties of the high-quality recycled aluminum alloy obtained in this embodiment are: tensile strength of 234 MPa; elongation at break of 3.8%.

Example 5. Al-9.72Si-2.6Cu-0.4La-0.3Ce-0.3Y-0.1Mn-0.1Cr (wt.%) secondary aluminum alloy and its preparation.

The preparation method described in this embodiment specifically includes the following steps.

(1) Raw material smelting: The ADC12 recycled aluminum obtained in Comparative Example 1 was weighed, and then heated and smelted in a vacuum high-frequency induction electromagnetic induction furnace. The smelting temperature was controlled at 760 °C to fully melt, and then argon was introduced for degassing.

(2) Refining and alloy composition adjustment: After the secondary aluminum alloy melt melted in step (1) is cooled to 730 °C, Al-30RE, Al-30Mn, and Al-20Cr are added to it for refining and metamorphism, and the slag is removed after holding for 20 min. , filter, where RE is the mixed rare earth of La, Ce, Y; then according to the composition according to the mass percentage, add industrial pure Al, Al-30Si master alloy to adjust the composition, after the master alloy is all melted, stir evenly, and then introduce nitrogen, The time was controlled at 5 min, and the secondary aluminum alloy with adjusted composition was obtained after standing for 30 min.

(3) Casting: first preheat the mold at 200 °C for 10 min, then cool down the aluminum alloy melt obtained in step (2) to 690 °C, pour the aluminum alloy solution into the mold, and cool it to room temperature to obtain an ingot.

The alloy composition in step (2) is adjusted according to the mass percentage of the prepared secondary aluminum alloy: Si: 9.72 wt.%, Cu: 2.6 wt.%, La: 0.4 wt.%, Ce: 0.3 wt.% %, Y: 0.3 wt.%, Mn: 0.1 wt.%, Cr: 0.1 wt.%, and the balance is Al and impurities such as Fe, Mg, Zn, and Ti. Among them, it was found that: Fe: 0.47%, Mg: 0.16%, Zn: 0.32%, Ti: 0.08%, and with (Fe, Mn)Al ₆ , (Cr, Fe)Al ₇ , FeRESiAl, Mg ₂ Si, MgZn ₂ , TiAl ₂ and other forms exist.

The room temperature tensile mechanical properties of the high-quality recycled aluminum alloy obtained in this embodiment are: tensile strength of 223 MPa; elongation at break of 3.5%.

The preparation method of the above-mentioned secondary aluminum alloy, the formula can optimize the prepared aluminum alloy structure, transform the difficult-to-remove impurities such as Fe, Mg, Zn, Ti in the alloy into a strengthening phase, and can also improve the needle-like Fe-rich in the aluminum alloy. The phase is effectively broken into short rods or Chinese characters, and the eutectic Si phase in the aluminum alloy can be refined into a network structure or fiber structure, and evenly distributed on the matrix, and it also has the ability to purify the melt. And degassing and other effects, the number and size of pinholes on the alloy are significantly reduced.

At the same time, it can adapt to the preparation requirements of different occasions, and is beneficial to industrial application.

Aluminum alloy tensile test: refer to the tensile strength, yield strength and elongation of aluminum alloy tested in "GB/T 228.1-2010 Tensile Test of Metal Materials Part 1: Test Method at Room Temperature". Tensile test bars (diameter 6.4 mm*gauge length 50 mm) with different compositions were obtained by general casting methods, and the tensile properties were tested by a Labsans 30 kN electronic universal testing machine with a gauge length of 50 mm and a loading rate of 2 mm/min, the test results are as follows:

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The formulations and preparation methods in the embodiments of the present invention have the following beneficial effects.

(1) The formula of the present invention can convert the impurities that are difficult to remove in the regenerated ADC12 aluminum alloy into a reinforcing phase, and at the same time, La, Ce and Y rare earth elements can effectively break the needle-shaped Fe-rich phase, and at the same time have the functions of removing impurities and degassing. , while the combination of Mn and Cr makes the needle-like Fe-rich phase form Chinese characters or fishbone. The effect of Fe-rich relative splitting of the matrix is eliminated; and the alloy has both higher strength (234 MPa) and plasticity (3.8%), which are increased by 57% and 216%, respectively.

(2) The regenerated ADC12 aluminum alloy prepared by the present invention has a uniformly distributed strengthening phase, which helps to refine the eutectic Si phase, reduces the effect of eutectic Si on the splitting of the matrix, and can effectively improve the mechanical properties of the aluminum alloy.

(3) The preparation method of the present invention is simple, and the preparation method adopts a die-casting molding process, which has low cost and is beneficial to industrialization.

This specific embodiment is only an explanation of the present invention, and it does not limit the present invention. Those skilled in the art can make modifications without creative contribution to the present embodiment as required after reading this specification, but as long as the rights of the present invention are used All claims are protected by patent law.

Claims (4)

1. A method for preparing regenerated ADC12 aluminum alloy from scrap aluminum is characterized by comprising the following steps:

(1) heating and smelting the waste aluminum impurities by using a vacuum high-frequency induction electromagnetic induction furnace, controlling the smelting temperature to be 740-760 ℃ for full smelting, and then introducing argon for degassing;

(2) cooling the waste and impurity aluminum alloy melt melted in the step (1) to 730 ℃, adding Al-30RE, Al-10Mn and Al-10Cr into the melt for refining and modification, stirring the melt for 1-2 min by using a graphite rod, keeping the temperature for 20min, slagging off and filtering, wherein RE is mixed rare earth of La, Ce and Y; adding an industrial pure Al and Al-30Si intermediate alloy according to the mass percentage of the components to adjust the components, uniformly stirring after the intermediate alloy is completely melted, blowing nitrogen for 5min, and standing for 20-30 min to obtain a regenerated aluminum alloy with adjusted components;

(3) pouring the aluminum alloy solution prepared in the step (2) into a mold, and cooling to room temperature to obtain an ingot;

adjusting the alloy components in the step (2), and according to the mass percent of the prepared regenerated aluminum alloy, the alloy components comprise the following components: si: 9.6-12 wt.%, Cu: 1.5-3.5 wt.%, La: 0.01-1.0 wt.%, Ce: 0.01-1.0 wt.%, Y: 0.01-1.0 wt.%, Mn: 0.01-0.2 wt.%, Cr: 0.01-0.2 wt.%, wherein impurities are controlled as follows: fe <1.3 wt.%, Mg <0.3 wt.%, Zn <1.0 wt.%, Ti: <0.2 wt.%, balance Al, wherein the total amount of rare earth elements La, Ce and Y does not exceed 1 wt.%.

2. The method for preparing the recycled ADC12 aluminum alloy from the waste aluminum according to claim 1, wherein the mass percentage of the components of the recycled aluminum alloy prepared is as follows: si: 9.6-12 wt.%, Cu: 1.5-3.5 wt.%, La: 0.01-0.5 wt.%, Ce: 0.01-0.5 wt.%, Y: 0.01-0.5 wt.%, Mn: 0.01-0.15 wt.%, Cr: 0.01-0.15 wt.%, wherein impurities are controlled as follows: fe <1.0 wt.%, Mg <0.25 wt.%, Zn <0.8 wt.%, Ti: <0.15 wt.%, with the balance being Al, wherein the total amount of rare earth elements La, Ce and Y does not exceed 1 wt.%.

3. The method for preparing recycled ADC12 aluminum alloy from scrap aluminum according to claim 1, wherein the casting temperature interval in step (3) is as follows: 690-700 ℃.

4. The method for preparing recycled ADC12 aluminum alloy from scrap aluminum according to claim 1, wherein the preheating temperature of the die in the step (3) is 200-250 ℃.

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