JP2024546409A - Non-heat-treated high-toughness Al-Si alloy die-casting material and its manufacturing method - Google Patents

Abstract

【summary】
The present invention discloses a non-heat-treated high-toughness Al-Si alloy die-casting material and its manufacturing process. The alloy can effectively suppress the adverse effects of Fe element by controlling the Mn/Fe ratio within a certain range. In addition, rare earth is introduced at a certain ratio to effectively refine the Si in the material and form a high-temperature phase together with elements such as Al and Cu, thereby improving the deformation resistance when the material is applied to large structural parts integrally molded by die-casting. After sampling and testing the main body of a large die-casting product, the F material of the alloy can reach a tensile strength of 290 MPa, a yield strength of 140 MPa, and an elongation of 13%, and has excellent die-castability and uses clean energy, so as to meet the standard of low carbon emissions.

Description

<Cross-reference to related applications>

This application claims priority to Chinese Patent Application No. 202111507879.5 filed on December 10, 2021 (titled "Non-heat-treatable high-toughness Al-Si alloy die-casting material and manufacturing method thereof"), the entirety of which is incorporated herein by reference.

The present invention relates to the technical field of metallic materials, specifically to non-heat-treated high-toughness Al-Si alloy die-casting material and its manufacturing method.

With the further promotion of the "peaking out of _CO2 emissions and becoming carbon neutral" policy, the carbon emission target value is gradually lowered. Recycled aluminum has the obvious advantage of low energy consumption, and can break away from the aluminum industry's dependence on electricity, which causes the price to rise with the increase in electricity prices. Therefore, making the recycled aluminum industry the leading industry will contribute to the healthy, stable, and long-term development of the aluminum industry. The carbon emissions of recycled aluminum are significantly lower than those of new aluminum ingot production using electrolysis with thermal power generation. The carbon dioxide emissions of one ton of new aluminum ingot produced using electrolysis with thermal power generation are about 12 tons, while the carbon dioxide emissions of one ton of recycled aluminum are only about 300 kg. In addition, its production can save 3.4 tons of standard coal and 14 cubic meters of water, and reduce the emission of solid waste by 20 tons. Based on the calculation that one ton of standard coal emits 3 tons of carbon dioxide, one ton of recycled aluminum, together with the carbon dioxide emissions from other auxiliary materials, can reduce a total of about 11.5 tons of carbon dioxide emissions. At the same time, recycled aluminum also has great economic benefits. The production of virgin aluminum requires the mining of bauxite and long-distance transportation, and the extraction of alumina and the production of virgin aluminum through electrolysis using thermal power generation consume huge amounts of energy, so the production cost of recycled aluminum is lower than that of virgin aluminum. With the rapid growth of China's aluminum scrap reserves and the continuous improvement of the waste resource recycling system, the price of aluminum scrap is expected to further decline, and the cost advantage of recycled aluminum production over the production of virgin aluminum through electrolysis using thermal power generation is expected to become more prominent. In addition, it is also possible to consider replacing electrolysis in the production of virgin aluminum with clean energy that does not emit carbon dioxide, such as hydroelectric, wind, and solar power.

In recent years, new energy vehicles have been appearing and developing one after another. However, due to the constraints of the weight and driving range of the drive battery, as well as strict automobile energy conservation and carbon emission reduction policies, there is a higher demand for lighter body weight in the vehicle design and material selection of battery-powered new energy vehicles than in traditional automobiles. Aluminum alloy is one of the lightweight materials and has comparative advantages in terms of technology, operational safety and recycling. Therefore, it has gradually replaced steel in the automobile industry, and has been widely used in the manufacture of automobile parts through the application of die-casting molding process.

The automotive and aerospace industries place strict requirements on parts, especially for excellent impact toughness and high elongation during deformation. Based on these requirements, the automotive industry requires aluminum alloy die-casting products with tensile strength exceeding 180MPa, yield strength exceeding 120MPa, and elongation exceeding 10% for large integrated body structural parts. Conventional Al-Si alloys have high strength and good castability. However, due to their poor plasticity and low elongation, they cannot meet the standards for large integrated die-casting products for automobiles. In recent years, the development of high-toughness aluminum alloys has attracted more and more attention to meet the demands of the automotive industry market. For example, the Silafont-36 alloy (Patent Publication No.: US 6364970B1) developed by Rheinland of Germany has an elongation of less than 6% at room temperature, but after long-term T7 heat treatment, it has a tensile strength of about 210Mpa, a yield strength of 140Mpa, and an elongation of 15%, which can meet the requirements of automotive structural parts. However, the production efficiency of this process is low, the heat treatment process is complicated, and it is difficult to properly control the heat treatment process, so the heat treatment cost is very high. Another example is the non-heat-treated reinforced high-strength and high-toughness Al-Mg-Si alloy die-casting material (patent disclosure number: CN 108754256A) developed by Shanghai Jiao Tong University, which has better mechanical properties, but because it is an Al-Mg-Si alloy, it has poor castability and is prone to oxidation and burning due to its high magnesium content. In addition to the above, the aluminum liquid of this alloy has high viscosity and shrinkage rate, which causes strong erosion of the die-casting mold and shortens the life of the mold, making it unsuitable for large body structural parts. In addition, Fengyang Aersi and Shanghai Jiao Tong University have developed a non-heat-treated self-reinforced Al-Si alloy (patent disclosure number: CN 104831129A). However, this alloy has high requirements for impurity elements, and it is impossible to use aluminum scrap in its production, which means that it cannot meet the various targets based on the future "peaking _CO2 emissions and becoming carbon neutral". In addition, the elongation of the castings of this alloy after precision die casting is about 7.5%, which does not meet the high toughness requirements of large body structural parts at the current stage. Furthermore, the high-strength and tough aluminum alloy die casting material (patent publication number: CN 109881056A) developed by Shanghai Yongmaotai Automotive Parts and Shanghai Jiao Tong University has good castability, but the elongation of the die castings in a non-heat-treated state is only 7%, which is not applicable to automotive structural parts that require high toughness. The high-toughness aluminum alloy die-casting material (patent publication number: CN 106636787A) developed by Suzhou Huichi Light Alloy has good castability and strength, but the impurity element content must be less than 0.005%, which places extremely high requirements on the impurity content, making it impossible to use aluminum scrap in its production. Meanwhile, the elongation of the die-cast product in a non-heat-treated state is only 9.7%, making it unsuitable for automotive structural parts that require high toughness.

This Summary introduces in a simplified form the concepts that are subsequently described in detail in the Examples. It is not intended to identify the main and essential features of the claimed technical solution, nor to limit the scope of the claimed technical solution.

The present invention provides a non-heat-treatable, high-toughness Al-Si alloy die-casting material that reduces carbon emissions and achieves an elongation of 11% to 16% without heat treatment, and a manufacturing method thereof.

In aspect 1 of the present invention, the mass percentages of each component of the non-heat-treated high-toughness Al-Si alloy die casting material provided in the examples of the present invention, based on the total weight of the alloy, are as follows:

Si: 6.3-8.3%, Fe: 0.07-0.45%, Cu: 0.05-0.5%, Mn: 0.5-0.8%, Mg: 0.15-0.35%, Ti: 0.01-0.2%, Sr: 0.015-0.035%, total amount of rare earths consisting of one or more of La/Ce/Sc: 0.04%-0.2%, Ni: 0.001-0.1%, Zn: 0.005-0.1%, Ga: 0.01-0.03%, and the total amount of other impurities is preferably 0.2% or less, with the balance being Al.

The mass percentage of each component of the Al-Si alloy die casting material may be as follows:

Si: 6.3-7.0%, Fe: 0.2-0.4%, Cu: 0.35-0.45%, Mn: 0.5-0.8%, Mg: 0.25-0.35%, Ti: 0.1-0.2%, Sr: 0.015-0.035%, total amount of rare earths consisting of one or more of La/Ce/Sc: 0.04%-0.2%, Ni: 0.001-0.1%, Zn: 0.005-0.1%, Ga: 0.01-0.03%, and the total amount of other impurities is preferably 0.2% or less, with the balance being Al.

The mass percentage of each component of the Al-Si alloy die casting material may be as follows:

Si: 6.4-7.1%, Fe: 0.10-0.25%, Cu: 0.05-0.28%, Mn: 0.5-0.8%, Mg: 0.25-0.35%, Ti: 0.03-0.16%, Sr: 0.025-0.035%, total amount of rare earths consisting of one or more of La/Ce/Sc: 0.04%-0.15%, Ni: 0.001-0.1%, Zn: 0.005-0.1%, Ga: 0.01-0.03%, and the total amount of other impurities is preferably 0.2% or less, with the balance being Al.

The mass percentage of each component of the Al-Si alloy die casting material may be as follows:

Si: 7.0-7.7%, Fe: 0.15-0.3%, Cu: 0.2-0.35%, Mn: 0.6-0.8%, Mg: 0.2-0.3%, Ti: 0.05-0.2%, Sr: 0.015-0.035%, total amount of rare earths consisting of one or more of La/Ce/Sc: 0.04%-0.2%, Ni: 0.001-0.1%, Zn: 0.005-0.1%, Ga: 0.01-0.03%, and the total amount of other impurities is preferably 0.2% or less, with the balance being Al.

The mass percentage of each component of the Al-Si alloy die casting material may be as follows:

Si: 7.7-8.3%, Fe: 0.07-0.2%, Cu: 0.05-0.2%, Mn: 0.6-0.8%, Mg: 0.15-0.3%, Ti: 0.01-0.15%, Sr: 0.015-0.035%, total amount of rare earths consisting of one or more of La/Ce/Sc: 0.04%-0.2%, Ni: 0.001-0.1%, Zn: 0.005-0.1%, Ga: 0.01-0.03%, and the total amount of other impurities is preferably 0.2% or less, with the balance being Al.

The Al-Si alloy die casting material can exhibit a tensile strength of 270 MPa or more, a yield strength of 130 MPa or more, and an elongation of 11% or more.

As a second aspect of the present invention, the manufacturing process of the Al-Si alloy die-cast material provided in the embodiment of the present invention is as follows.

First, the raw materials that are unlikely to burn are heated and melted to prepare the Al-Si alloy die-cast material to obtain an aluminum alloy liquid. Next, the raw materials that are likely to burn are added to the aluminum alloy liquid after slag removal and refining, and after the components reach the specified values, a casting process is performed to obtain the Al-Si alloy die-cast material.

The present invention allows the Al-Si alloy die-casting material to be die-cast. The Al-Si alloy die-casting material is characterized in that the forming temperature is 680-720°C, the die-casting speed is 2.5-5 m/s, and the heat retention time is 2-10 seconds, resulting in a die-cast product in a non-heat-treated state.

In the present invention, after each raw material is completely melted, the aluminum alloy liquid is uniformly stirred and allowed to stand, after which sampling and analysis are performed, and the content of the necessary elements can be adjusted to within the required range of the component ratio.

The present invention allows the refining flux used to be free of sodium ions.

The present invention provides a non-heat-treated high-toughness Al-Si alloy die-casting material and its manufacturing method. The aluminum alloy prepared by the present invention overcomes the limitations of conventional aluminum alloy die-casting materials that require T7 heat treatment to meet the requirements of structural parts of automobile bodies, and can be manufactured from aluminum scrap, reducing carbon emissions generated during the manufacturing process and achieving an elongation of 11-16% without heat treatment.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the invention which is claimed.

The above and other features, advantages, and aspects of the embodiments of the present disclosure will become more apparent with reference to the accompanying drawings and the following embodiments. Throughout the accompanying drawings, the same or similar affixed reference numerals refer to the same or similar elements. It should be understood that the accompanying drawings are schematic, and that the drawings and elements are not necessarily drawn to scale.
1A and 1B are metallographic diagrams of the microstructure of an aluminum die casting obtained in Example 2 of the present invention, where FIG. 1A is a metallographic diagram of the microstructure at 100 times magnification, and FIG. 1B is a metallographic diagram of the microstructure at 500 times magnification. 1 is a fluidity test mold for aluminum die casting obtained in Example 2. 1 shows tensile stress-strain curves of the aluminum die castings obtained in Example 2, Comparative Example 1, and Comparative Example 2.

Below, the embodiments of the present disclosure will be described in more detail with reference to the attached drawings. Although some embodiments are shown in the attached drawings, it should be understood that the present disclosure is not limited thereto and can be implemented in various forms beyond the scope of the embodiments described below. The provision of these embodiments is for the purpose of a more complete and thorough understanding of the present disclosure. It should also be understood that the attached drawings and embodiments of the present disclosure are merely illustrative and are not intended to limit the scope of protection of the present disclosure.

It should be understood that the steps described in the embodiments of the disclosed methods may be performed in different orders and/or in parallel. Additionally, the embodiments of the disclosed methods may include additional steps and/or omit the performance of steps shown. Accordingly, the scope of the disclosure is not limited in any way.

The present disclosure provides a non-heat-treated high-toughness Al-Si alloy die-cast material and a manufacturing method thereof. Below, examples of the present disclosure are described in detail with reference to the attached drawings.

Example 1
The non-heat-treated, high-toughness Al-Si alloy die-cast material with low carbon emissions and renewable properties of this embodiment contains, by mass, the following components: Mg: 0.2%, Si: 6.5%, Fe: 0.15%, Cu: 0.1%, Mn: 0.5%, Ti: 0.03%, Sr: 0.025%, total amount of La and Ce: 0.05%, Ni: 0.005%, Zn: 0.006%, Ga: 0.015%, with the remainder being aluminum and remaining impurities of 0.2% or less.

The manufacturing method of this embodiment for producing a non-heat-treated, highly tough Al-Si alloy die casting that has low carbon emissions and is renewable includes the following steps:

(1) Preparation before putting into the furnace: Clean the bottom of the furnace and preheat it until the furnace walls turn red. At the same time, apply graphite powder to all work tools, dry them, and preheat them.

(2) Materials: Prepare the raw materials for each element that makes up the aluminum alloy, such as metallic Al ingot, metallic Mg ingot, industrial silicon, Al-Mn intermediate alloy or metallic Mn, metallic Fe, Al-Ti intermediate alloy, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga, Al-Sr intermediate alloy, and rare earth aluminum intermediate alloy, in advance and add them according to the alloy component ratios listed above, taking into account the amount of burnt damage.

(3) Melting in furnace: First, the Al metal ingot is placed in the furnace and melted while maintaining the melting temperature at 760-790°C. After the Al ingot is completely melted, the temperature is increased and the furnace temperature is maintained at 760-780°C. Industrial silicon, Fe metal, Al-Mn intermediate alloy or Mn metal, Cu metal or Al-Cu intermediate alloy, Ni metal, Zn metal and Ga metal are added for smelting.

(4) Refining and slag treatment: The aluminum alloy melt is stirred uniformly while maintaining the temperature at 740-760°C, and a special refining flux for aluminum alloys is added, followed by primary and secondary refining by powder injection. The time interval between two refinings is controlled to 50-60 minutes, and slag treatment is carried out after each refining to remove the flux and floating dross on the liquid surface.

(5) Addition of other metal elements: While maintaining the molten metal temperature at 740-760°C, ingots of Al-Ti intermediate alloy, rare earth aluminum intermediate alloy, metallic Mg, and Al-Sr intermediate alloy are added to the furnace and smelted, refined, and inoculated to obtain an aluminum alloy melt, which is then sampled and analyzed.

(6) Furnace degassing. While maintaining the smelting temperature at 740-760°C, degas the furnace using gas for approximately 30-50 minutes, then leave it to stand for 15-30 minutes.

(7) Casting or die casting: After the component analysis results before putting into the furnace are found to be acceptable, casting is carried out at an appropriate casting temperature to create an ingot, or high-pressure casting is carried out using a die casting process to create a die-cast product in an unheated state.

Example 2
The non-heat treated, high-toughness Al-Si alloy die casting material with low carbon emissions and renewable properties of this embodiment contains, by mass, the following components: Mg: 0.3%, Si: 6.9%, Fe: 0.2%, Cu: 0.2%, Mn: 0.6%, Ti: 0.07%, Sr: 0.02%, La: 0.1%, Ni: 0.003%, Zn: 0.07%, Ga: 0.02%, with the remainder being aluminum and 0.2% or less of remaining impurities.

The manufacturing method of this embodiment for producing a non-heat-treated, highly tough Al-Si alloy die casting that has low carbon emissions and is renewable includes the following steps:

(1) Preparation before putting into the furnace: Clean the bottom of the furnace and preheat it until the furnace walls turn red. At the same time, apply graphite powder to all work tools, dry them, and preheat them.

(2) Materials: Prepare the raw materials for each element that makes up the aluminum alloy, such as metallic Al ingot or aluminum scrap, metallic Mg ingot, industrial silicon, Al-Mn intermediate alloy or metallic Mn, metallic Fe, Al-Ti intermediate alloy, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga, Al-Sr intermediate alloy, and rare earth aluminum intermediate alloy, in advance and add them according to the alloy component ratios listed above, taking into account the amount of burnt damage.

(3) Melting in furnace: First, aluminum metal ingots or aluminum scrap are put into the furnace and melted while maintaining the melting temperature at 760-790°C. After the aluminum ingots or aluminum scrap have all melted, the temperature is increased and the furnace temperature is maintained at 760-780°C, and industrial silicon, metallic Fe, Al-Mn intermediate alloy or metallic Mn, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga are added for smelting.

(4) Refining and slag treatment: The aluminum alloy melt is stirred uniformly while maintaining the temperature at 740-760°C, and a special refining flux for aluminum alloys is added, followed by primary and secondary refining by powder injection. The time interval between two refinings is controlled to 50-60 minutes, and slag treatment is carried out after each refining to remove the flux and floating dross on the liquid surface.

(5) Addition of other metal elements: While maintaining the molten metal temperature at 740-760°C, ingots of Al-Ti intermediate alloy, rare earth aluminum intermediate alloy, metallic Mg, and Al-Sr intermediate alloy are added to the furnace and smelted, refined, and inoculated to obtain an aluminum alloy melt, which is then sampled and analyzed.

(6) Furnace degassing. While maintaining the smelting temperature at 740-760°C, degas the furnace with nitrogen gas for approximately 30-50 minutes, then leave it to stand for 15-30 minutes.

(7) Casting or die casting: After the component analysis results before putting into the furnace are found to be acceptable, casting is carried out at an appropriate casting temperature to create an ingot, or high-pressure casting is carried out using a die casting process to create a die-cast product in an unheated state.

Example 3
The non-heat treated, high-toughness Al-Si alloy die casting material with low carbon emissions and renewable properties of this embodiment contains, by mass, the following components: Mg: 0.35%, Si: 7.5%, Fe: 0.25%, Cu: 0.3%, Mn: 0.7%, Ti: 0.15%, Sr: 0.03%, Ce: 0.08%, Ni: 0.08%, Zn: 0.09%, Ga: 0.025%, with the remainder being aluminum and less than 0.2% remaining impurities.

The manufacturing method of this embodiment for producing a non-heat-treated, highly tough Al-Si alloy die casting that has low carbon emissions and is renewable includes the following steps:

(1) Preparation before putting into the furnace: Clean the bottom of the furnace and preheat it until the furnace walls turn red. At the same time, apply graphite powder to all work tools, dry them, and preheat them.

(2) Materials: Prepare the raw materials for each element that makes up the aluminum alloy, such as metallic Al ingot or aluminum scrap, metallic Mg ingot, industrial silicon, Al-Mn intermediate alloy or metallic Mn, metallic Fe, Al-Ti intermediate alloy, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga, Al-Sr intermediate alloy, and rare earth aluminum intermediate alloy, in advance and add them according to the alloy component ratios listed above, taking into account the amount of burnt damage.

(3) Melting in furnace: First, aluminum metal ingots or aluminum scrap are put into the furnace and melted while maintaining the melting temperature at 760-790°C. After the aluminum ingots or aluminum scrap have all melted, the temperature is increased and the furnace temperature is maintained at 760-780°C, and industrial silicon, metallic Fe, Al-Mn intermediate alloy or metallic Mn, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga are added for smelting.

(4) Refining and slag treatment: The aluminum alloy melt is stirred uniformly while maintaining the temperature at 740-760°C, and a special refining flux for aluminum alloys is added, followed by primary and secondary refining by powder injection. The time interval between two refinings is controlled to 50-60 minutes, and slag treatment is carried out after each refining to remove the flux and floating dross on the liquid surface.

(5) Addition of other metal elements: While maintaining the molten metal temperature at 740-760°C, ingots of Al-Ti intermediate alloy, rare earth aluminum intermediate alloy, metallic Mg, and Al-Sr intermediate alloy are added to the furnace and smelted, refined, and inoculated to obtain an aluminum alloy melt, which is then sampled and analyzed.

(6) Furnace degassing. While maintaining the smelting temperature at 740-760°C, degas the furnace with nitrogen gas for approximately 30-50 minutes, then leave it to stand for 15-30 minutes.

(7) Casting or die casting: After the component analysis results before putting into the furnace are found to be acceptable, casting is carried out at an appropriate casting temperature to create an ingot, or high-pressure casting is carried out using a die casting process to create a die-cast product in an unheated state.

Example 4
The non-heat treated, high-toughness Al-Si alloy die casting material with low carbon emissions and renewable properties of this embodiment contains, by mass, the following components: Mg: 0.25%, Si: 7.8%, Fe: 0.35%, Cu: 0.4%, Mn: 0.8%, Ti: 0.2%, Sr: 0.035%, Sc: 0.15%, Ni: 0.02%, Zn: 0.08%, Ga: 0.012%, with the remainder being aluminum and 0.2% or less of remaining impurities.

The manufacturing method of this embodiment for producing a non-heat-treated, highly tough Al-Si alloy die casting that has low carbon emissions and is renewable includes the following steps:

(1) Preparation before putting into the furnace: Clean the bottom of the furnace and preheat it until the furnace walls turn red. At the same time, apply graphite powder to all work tools, dry them, and preheat them.

(2) Materials: Prepare the raw materials for each element that makes up the aluminum alloy, such as metallic Al ingot or aluminum scrap, metallic Mg ingot, industrial silicon, Al-Mn intermediate alloy or metallic Mn, metallic Fe, Al-Ti intermediate alloy, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga, Al-Sr intermediate alloy, and rare earth aluminum intermediate alloy, in advance and add them according to the alloy component ratios listed above, taking into account the amount of burnt damage.

(3) Melting in furnace: First, aluminum metal ingots or aluminum scrap are put into the furnace and melted while maintaining the melting temperature at 760-790°C. After the aluminum ingots or aluminum scrap have all melted, the temperature is increased and the furnace temperature is maintained at 760-780°C, and industrial silicon, metallic Fe, Al-Mn intermediate alloy or metallic Mn, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga are added for smelting.

(4) Refining and slag treatment: The aluminum alloy melt is stirred uniformly while maintaining the temperature at 740-760°C, and a special refining flux for aluminum alloys is added, followed by primary and secondary refining by powder injection. The time interval between two refinings is controlled to 50-60 minutes, and slag treatment is carried out after each refining to remove the flux and floating dross on the liquid surface.

(5) Addition of other metal elements: While maintaining the molten metal temperature at 740-760°C, ingots of Al-Ti intermediate alloy, rare earth aluminum intermediate alloy, metallic Mg, and Al-Sr intermediate alloy are added to the furnace and smelted, refined, and inoculated to obtain an aluminum alloy melt, which is then sampled and analyzed.

(6) Furnace degassing. While maintaining the smelting temperature at 740-760°C, degas the furnace with nitrogen gas for approximately 30-50 minutes, then leave it to stand for 15-30 minutes.

(7) Casting or die casting: After the component analysis results before putting into the furnace are found to be acceptable, casting is carried out at an appropriate casting temperature to create an ingot, or high-pressure casting is carried out using a die casting process to create a die-cast product in an unheated state.

Example 5
The non-heat-treated, high-toughness Al-Si alloy die-cast material with low carbon emissions and renewable properties of this embodiment contains, by mass, the following components: Mg: 0.15%, Si: 8.3%, Fe: 0.45%, Cu: 0.5%, Mn: 0.65%, Ti: 0.15%, Sr: 0.03%, total amount of La and Sc: 0.2%, Ni: 0.08%, Zn: 0.01%, Ga: 0.018%, with the remainder being aluminum and less than 0.2% remaining impurities.

The manufacturing method of this embodiment for producing a non-heat-treated, highly tough Al-Si alloy die casting that has low carbon emissions and is renewable includes the following steps:

(1) Preparation before putting into the furnace: Clean the bottom of the furnace and preheat it until the furnace walls turn red. At the same time, apply graphite powder to all work tools, dry them, and preheat them.

(2) Materials: Prepare the raw materials for each element that makes up the aluminum alloy, such as metallic Al ingot or aluminum scrap, metallic Mg ingot, industrial silicon, Al-Mn intermediate alloy or metallic Mn, metallic Fe, Al-Ti intermediate alloy, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga, Al-Sr intermediate alloy, and rare earth aluminum intermediate alloy, in advance and add them according to the alloy component ratios listed above, taking into account the amount of burnt damage.

(3) Melting in furnace: First, aluminum metal ingots or aluminum scrap are put into the furnace and melted while maintaining the melting temperature at 760-790°C. After the aluminum ingots or aluminum scrap have all melted, the temperature is increased and the furnace temperature is maintained at 760-780°C, and industrial silicon, metallic Fe, Al-Mn intermediate alloy or metallic Mn, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga are added for smelting.

(4) Refining and slag treatment: The aluminum alloy melt is stirred uniformly while maintaining the temperature at 740-760°C, and a special refining flux for aluminum alloys is added, followed by primary and secondary refining by powder injection. The time interval between two refinings is controlled to 50-60 minutes, and slag treatment is carried out after each refining to remove the flux and floating dross on the liquid surface.

(5) Addition of other metal elements: While maintaining the molten metal temperature at 740-760°C, ingots of Al-Ti intermediate alloy, rare earth aluminum intermediate alloy, metallic Mg, and Al-Sr intermediate alloy are added to the furnace and smelted, refined, and inoculated to obtain an aluminum alloy melt, which is then sampled and analyzed.

(6) Furnace degassing. While maintaining the smelting temperature at 740-760°C, degas the furnace with nitrogen gas for approximately 30-50 minutes, then leave it to stand for 15-30 minutes.

(7) Casting or die casting: After the component analysis results before putting into the furnace are found to be acceptable, casting is carried out at an appropriate casting temperature to create an ingot, or high-pressure casting is carried out using a die casting process to create a die-cast product in an unheated state.

Example 6
The low carbon emission, renewable, non-heat-treated, high-toughness Al-Si alloy die-cast material of this embodiment is manufactured using recycled aluminum scrap as raw material through the following process.

(1) Preparation before putting into the furnace: Clean the bottom of the furnace and preheat it until the furnace walls turn red. At the same time, apply graphite powder to all work tools, dry them, and preheat them.

(2) Materials: First, recycled aluminum scrap is sorted and processed. Next, based on the alloy component ratio, the raw materials for each element that makes up the aluminum alloy, such as metallic Al ingot, metallic Mg ingot, industrial silicon, Al-Mn intermediate alloy or metallic Mn, metallic Fe, Al-Ti intermediate alloy, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga, Al-Sr intermediate alloy, and rare earth aluminum intermediate alloy, are prepared and added according to the above alloy component ratio, taking into account the amount of burnt damage as appropriate.

(3) Melting in furnace: First, aluminum metal ingots and aluminum scrap are placed in the furnace in a mass ratio of 40% and 60% in the correct order, and smelted while maintaining the furnace temperature at 760-790°C. After everything is melted, sampling and analysis are performed, and other elements are added according to their respective ratios. Next, the temperature is increased, and the furnace temperature is maintained at 760-780°C, and industrial silicon, metallic Fe, Al-Mn intermediate alloy or metallic Mn, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga are added and smelted.

(4) Refining and slag treatment: The aluminum alloy melt that passed the component analysis is stirred uniformly while maintaining the temperature at 740-760°C, and a special refining flux for aluminum alloys is added, and primary and secondary refining is carried out by powder injection. The time interval between the two refining processes is controlled to 50-60 minutes, and slag treatment is carried out after each refining process to remove the flux and floating dross on the liquid surface.

(5) Addition of other metal elements: While maintaining the molten metal temperature at 740-760°C, ingots of Al-Ti intermediate alloy, rare earth aluminum intermediate alloy, metallic Mg, and Al-Sr intermediate alloy are added to the furnace and smelted, refined, and inoculated to obtain an aluminum alloy melt, which is then sampled and analyzed.

(6) Furnace degassing. While maintaining the smelting temperature at 740-760°C, degas the furnace with nitrogen gas for approximately 30-50 minutes, then leave it to stand for 15-30 minutes.

(7) Casting or die casting: The final mass percent content of each component is: Mg: 0.25%, Si: 7.0%, Fe: 0.35%, Cu: 0.25%, Mn: 0.6%, Ti: 0.12%, Sr: 0.028%, La/Ce/Sc total: 0.2%, Ni: 0.005%, Zn: 0.06%, Ga: 0.02%, and the remainder is aluminum and impurities of less than 0.2%. After the component analysis results before putting into the furnace are found to be acceptable, casting is performed at an appropriate casting temperature to create an ingot, and a die casting process is performed to cast at high pressure to create a die cast product in an unheated state.

Example 7
The low carbon emission, renewable, non-heat-treated, high-toughness Al-Si alloy die-cast material of this embodiment is manufactured using recycled aluminum scrap as raw material through the following process.

(1) Preparation before putting into the furnace: Clean the bottom of the furnace and preheat it until the furnace walls turn red. At the same time, apply graphite powder to all work tools, dry them, and preheat them.

(2) Materials: First, recycled aluminum scrap is sorted. Next, based on the alloy component ratio, the raw materials for each element that makes up the aluminum alloy, such as metallic Mg ingots, industrial silicon, Al-Mn intermediate alloy or metallic Mn, metallic Fe, Al-Ti intermediate alloy, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga, Al-Sr intermediate alloy, and rare earth aluminum intermediate alloy, are prepared and added according to the above alloy component ratio, taking into account the amount of burnt damage as appropriate.

(3) Melting in furnace: First, aluminum scrap is put into the furnace at a mass ratio of 100%, and smelted while maintaining the furnace temperature at 760-790°C. After it is all melted, sampling and analysis are carried out, and other elements are added according to their respective proportions. Next, the temperature is increased, and the furnace temperature is maintained at 760-780°C, and industrial silicon, metallic Fe, Al-Mn intermediate alloy or metallic Mn, metallic Cu or Al-Cu intermediate alloy, metallic Ni, metallic Zn and metallic Ga are added for smelting.

(4) Refining and slag treatment: The aluminum alloy melt that passed the component analysis is stirred uniformly while maintaining the temperature at 740-760°C, and a special refining flux for aluminum alloys is added, and primary and secondary refining is carried out by powder injection. The time interval between the two refining processes is controlled to 50-60 minutes, and slag treatment is carried out after each refining process to remove the flux and floating dross on the liquid surface.

(5) Addition of other metal elements: While maintaining the molten metal temperature at 740-760°C, ingots of Al-Ti intermediate alloy, rare earth aluminum intermediate alloy, metallic Mg, and Al-Sr intermediate alloy are added to the furnace and smelted, refined, and inoculated to obtain an aluminum alloy melt, which is then sampled and analyzed.

(6) Furnace degassing. While maintaining the smelting temperature at 740-760°C, degas the furnace with nitrogen gas for approximately 30-50 minutes, then leave it to stand for 15-30 minutes.

(7) Casting or die casting: The final mass percent content of each component is: Mg: 0.3%, Si: 7.7%, Fe: 0.15%, Cu: 0.3%, Mn: 0.7%, Ti: 0.15%, Sr: 0.035%, Ce: 0.08%, Ni: 0.1%, Zn: 0.1%, Ga: 0.03%, with the remainder being aluminum and impurities of 0.2% or less. After the component analysis results before putting into the furnace are found to be acceptable, casting is performed at an appropriate casting temperature to create an ingot, and a die casting process is performed to create a die cast product in a non-heat-treated state.

Comparative Example 1
This comparative example is based on Example 2, but the amount of Sr element has been reduced and the La element has been removed, and the contents of each component in mass% are: Si: 6.9%, Fe: 0.2%, Cu: 0.2%, Mn: 0.6%, Mg: 0.3%, Ti: 0.008%, Sr: 0.003%, Zn: 0.07%, Ga: 0.02%, and the remainder is aluminum and 0.2% or less of remaining impurities.

The manufacturing method for the aluminum alloy die-cast material in this comparative example includes the following steps:

(1) Preparation before putting into the furnace: Clean the bottom of the furnace and preheat it until the furnace walls turn red. At the same time, apply graphite powder to all work tools, dry them, and preheat them.

(2) Materials: Prepare the raw materials for each element that makes up the aluminum alloy, such as metallic Al ingot, metallic Mg ingot, industrial silicon, metallic Cu, Al-Mn intermediate alloy or metallic Mn, metallic Fe, Al-Ti intermediate alloy, and Al-Sr intermediate alloy, in advance and add them according to the alloy component ratios listed above, taking into account the amount of burnt damage.

(3) Melting in furnace: First, the aluminum metal ingot is placed in the furnace and smelting is carried out while maintaining the smelting temperature at 670-690°C. After the aluminum ingot is completely melted, the temperature is raised and the furnace temperature is maintained at 760-780°C, and industrial silicon, metallic Fe, metallic Cu, an Al-Mn intermediate alloy, or metallic Mn is added for smelting.

(4) Refining and slag treatment: The aluminum alloy melt that passed the component analysis is stirred uniformly while maintaining the temperature at 740-760°C, and a special refining flux for aluminum alloys is added, and primary and secondary refining is carried out by powder injection. The time interval between the two refining processes is controlled to 50-60 minutes, and slag treatment is carried out after each refining process to remove the flux and floating dross on the liquid surface.

(5) Addition of other metal elements: While maintaining the temperature of the molten metal at 740-760°C, ingots of Al-Ti intermediate alloy, metallic Mg, and Al-Sr intermediate alloy are added to the furnace and smelted to obtain an aluminum alloy melt, after which sampling and analysis are performed.

(6) Furnace degassing. While maintaining the smelting temperature at 740-760°C, degas the furnace with nitrogen gas for approximately 30-50 minutes, then leave it to stand for 15-30 minutes.

(7) Casting or die casting: After the component analysis results before putting into the furnace are found to be acceptable, casting is carried out at an appropriate casting temperature to create an ingot, or high-pressure casting is carried out using a die casting process to create a die-cast product in an unheated state.

Comparative Example 2
This comparative example is based on Example 2, but the amount of Sr element has been increased and the amount of La element has been removed. The contents of each component in mass% are: Si: 6.9%, Fe: 0.2%, Cu: 0.2%, Mn: 0.6%, Mg: 0.3%, Ti: 0.07%, Sr: 0.05%, Ni: 0.003%, Zn: 0.07%, Ga: 0.02%, and the remainder is aluminum and 0.2% or less of remaining impurities.

The manufacturing method for this comparative example is the same as that for comparative example 1.

Comparative Example 3
This comparative example is based on Example 6, but with the exception of the elements La, Ce, Sc, Zn, Ni, and Ga, and the contents of each component in mass% are: Si: 7.0%, Fe: 0.35%, Cu: 0.25%, Mn: 0.6%, Mg: 0.25%, Ti: 0.12%, Sr: 0.028%, with the remainder being aluminum and 0.2% or less of remaining impurities.

The manufacturing method for this comparative example is the same as that for comparative example 1.

Comparative Example 4

This comparative example is based on Example 6, but excluding the elements La, Ce, and Sc. The content of each component in mass percent is: Si: 7.0%, Fe: 0.35%, Cu: 0.25%, Mn: 0.6%, Mg: 0.25%, Ti: 0.12%, Sr: 0.028%, Ni: 0.06%, Zn: 0.005%, Ga: 0.02%, and the remainder is aluminum and less than 0.2% of remaining impurities.

The manufacturing method for this comparative example is the same as that for comparative example 1.

Comparative Example 5
This comparative example is based on Example 6, but with high additions of La, Ce, and Sc elements, and the contents of each component, in mass%, are: Si: 7.0%, Fe: 0.35%, Cu: 0.25%, Mn: 0.6%, Mg: 0.25%, Ti: 0.12%, Sr: 0.028%, La: 0.2%, Ce: 0.2%, Sc: 0.2%, Ni: 0.06%, Zn: 0.005%, Ga: 0.02%, with the remainder being aluminum and remaining impurities of 0.2% or less.

The manufacturing method for this comparative example is the same as that for comparative example 1.

Comparative Example 6
This comparative example is based on Example 6, but with a high La element added, and the contents of each component in mass% are: Si: 7.0%, Fe: 0.35%, Cu: 0.25%, Mn: 0.6%, Mg: 0.25%, Ti: 0.12%, Sr: 0.028%, La: 1.0%, Ni: 0.06%, Zn: 0.005%, Ga: 0.02%, with the remainder being aluminum and 0.2% or less of remaining impurities.

The manufacturing method for this comparative example is the same as that for comparative example 1.

Comparative Example 7
This comparative example is based on Example 6, but with a high addition of Sc element, and the contents of each component in mass% are: Si: 7.0%, Fe: 0.35%, Cu: 0.25%, Mn: 0.6%, Mg: 0.25%, Ti: 0.12%, Sr: 0.028%, Sc: 0.5%, Ni: 0.06%, Zn: 0.005%, Ga: 0.02%, with the remainder being aluminum and less than 0.2% remaining impurities.

The manufacturing method for this comparative example is the same as that for comparative example 1.

Comparative Example 8
This comparative example is based on Example 6, but with a high addition of Sc element, and the contents of each component in mass% are: Si: 7.0%, Fe: 0.35%, Cu: 0.25%, Mn: 0.6%, Mg: 0.25%, Ti: 0.12%, Sr: 0.028%, La: 0.01%, Sc: 0.01%, Ni: 0.06%, Zn: 0.005%, Ga: 0.02%, with the remainder being aluminum and less than 0.2% remaining impurities.

The manufacturing method for this comparative example is the same as that for comparative example 1.

Table 1 shows the compositions of the aluminum alloys produced in Examples 1 to 7 and Comparative Examples 1 to 8.

Table 2 shows the mechanical properties and fluidity measured at room temperature for the F materials sampled from the aluminum alloy ingot bodies produced in Examples 1 to 7 and Comparative Examples 1 to 8, and for the same materials heated at 180°C for 30 minutes.

According to Tables 1 and 2, in Comparative Example 1, the Sr element content was significantly reduced and no rare earths were added, compared to Example 2, and the yield strength was 26 MPa and the elongation was 4.2% lower. In Comparative Example 2, the Sr element content was significantly increased and no rare earths were added, compared to Example 2, and the yield strength was 17 MPa and the elongation was 4.9% lower. In Comparative Example 3, in which no rare earths, Zn, Ni, or Ga elements were added, the yield strength was 25 MPa and the elongation was 3.3% lower. In Comparative Example 4, in which no rare earths were added, the yield strength was 23 MPa and the elongation was 3.6% lower. In Comparative Example 5, in which the total amount of rare earths La, Ce, and Sc added was adjusted to 0.6%, the yield strength was 18 MPa and the elongation was 4.8% lower than in Example 6. In Comparative Example 6, in which the amount of rare earth La added was adjusted to 1.0%, the yield strength was 16 MPa and the elongation was 5.1% lower than in Example 6. In comparison with Example 6, Comparative Example 7, in which the amount of rare earth Sc added was adjusted to 0.5%, had a yield strength that was 20 MPa and an elongation that was 4.1% lower. In comparison with Example 6, Comparative Example 8, in which the total amount of rare earth La and Sc added was adjusted to 0.02%, had a yield strength that was 16 MPa and an elongation that was 4.2% lower. Therefore, only when the content of Sr and rare earth La, Ce, and Sc elements is within the range of the present invention can excellent mechanical properties be exhibited. If the content of Sr or rare earth La, Ce, and Sc elements is too low or too high, the overall mechanical properties are reduced.

The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited thereto. Various simple modifications can be made to the technical means of the present invention within the scope of the technical idea of the present invention, such as arbitrarily combining each technical feature in other suitable ways. All such simple modifications and combinations are considered to be the disclosure of the present invention and fall within the protection scope of the present invention.

Claims (10)

A non-heat-treated high-toughness Al-Si alloy die-cast material, characterized by the following mass percent content of each component: Si: 6.3-8.3%, Fe: 0.07-0.45%, Cu: 0.05-0.5%, Mn: 0.5-0.8%, Mg: 0.15-0.35%, Ti: 0.01-0.2%, Sr: 0.015-0.035%, total amount of rare earths including one or more of La/Ce/Sc: 0.04-0.2%, Ni: 0.001-0.1%, Zn: 0.005-0.1%, Ga: 0.01-0.03%, with the remainder being Al and 0.2% or less of remaining impurities. The Al-Si alloy die casting material according to claim 1, characterized in that the content of each component in mass percent is: Si: 6.3-7.0%, Fe: 0.2-0.4%, Cu: 0.35-0.45%, Mn: 0.5-0.8%, Mg: 0.25-0.35%, Ti: 0.1-0.2%, Sr: 0.015-0.035%, total amount of rare earths including one or more of La/Ce/Sc: 0.04-0.2%, Ni: 0.001-0.1%, Zn: 0.005-0.1%, Ga: 0.01-0.03%, and the balance is Al and 0.2% or less of remaining impurities. The non-heat-treated high-toughness Al-Si alloy die-cast material according to claim 1, characterized in that the content of each component in mass percent is: Si: 6.4-7.1%, Fe: 0.10-0.25%, Cu: 0.05-0.28%, Mn: 0.5-0.8%, Mg: 0.25-0.35%, Ti: 0.03-0.16%, Sr: 0.025-0.035%, total amount of rare earths including one of La/Ce/Sc: 0.04-0.15%, Ni: 0.001-0.1%, Zn: 0.005-0.1%, Ga: 0.01-0.03%, and the balance is Al and 0.2% or less of remaining impurities. The Al-Si alloy die casting material according to claim 1, characterized in that the content of each component in mass percent is: Si: 7.0-7.7%, Fe: 0.15-0.3%, Cu: 0.2-0.35%, Mn: 0.6-0.8%, Mg: 0.2-0.3%, Ti: 0.05-0.2%, Sr: 0.015-0.035%, total amount of rare earths including one or more of La/Ce/Sc: 0.04-0.2%, Ni: 0.001-0.1%, Zn: 0.005-0.1%, Ga: 0.01-0.03%, and the balance is Al and 0.2% or less of remaining impurities. The Al-Si alloy die casting material according to claim 1, characterized in that the content of each component in mass percent is: Si: 7.7-8.3%, Fe: 0.07-0.2%, Cu: 0.05-0.2%, Mn: 0.6-0.8%, Mg: 0.15-0.3%, Ti: 0.01-0.15%, Sr: 0.015-0.035%, total amount of rare earths including one or more of La/Ce/Sc: 0.04-0.2%, Ni: 0.001-0.1%, Zn: 0.005-0.1%, Ga: 0.01-0.03%, and the balance is Al and 0.2% or less of remaining impurities. An Al-Si alloy die-cast material according to any one of claims 1 to 5, characterized in that it has a tensile strength of 270 MPa or more, a yield strength of 130 MPa or more, and an elongation of 11% or more. The manufacturing process for the Al-Si alloy die-casting material according to any one of claims 1 to 6, characterized in that the raw material which is unlikely to burn is heated and melted to prepare the Al-Si alloy die-casting material, an aluminum alloy liquid is obtained, the aluminum alloy liquid is subjected to slag removal and refining, and then raw material which is likely to burn is added, and after the components reach the specified values, a casting process is performed to obtain the Al-Si alloy die-casting material. The manufacturing process described in claim 7 is characterized in that the Al-Si alloy die-cast material is die-cast at a forming temperature of 680 to 720°C, a die-casting speed of 2.5 to 5 m/s, and a heat-retention time of 2 to 10 seconds to obtain a die-cast product in a non-heat-treated state. The manufacturing process described in claim 7 is characterized in that after each raw material is completely melted, the aluminum alloy liquid is uniformly stirred and allowed to stand, after which sampling and analysis are performed, and the content of required elements is adjusted to within the required range of component ratio. 8. The process according to claim 7, characterized in that the refining flux used does not contain sodium ions.