A method for producing a high-performance aluminum-copper alloy

Abstract

The application discloses a production method of high-performance aluminum-copper alloy and belongs to the technical field of aluminum-copper alloy. Through forced stirring action of a double-chamber furnace and a liquid aluminum purification system outside the furnace, the problems of unstable quality such as composition segregation, high gas content and high slag content of high-performance aluminum-copper alloy produced by a 20-ton or more furnace are solved. The application for the invention patent is protected, which is favorable for protection of production technology of the company, is favorable for improvement of comprehensive competitiveness of the company in the field of aluminum alloy production as intangible assets of the company.

Description

Technical Field

[0001] This invention relates to the field of aluminum-copper alloy technology, and more specifically to a method for producing high-performance aluminum-copper alloys. Background Technology

[0002] Aluminum-copper alloys are aluminum alloys with copper as the main alloying element. They are the earliest cast aluminum alloys used in industry. They not only have high specific strength, specific modulus, fracture toughness, fatigue strength and corrosion resistance, but also have good formability and weldability. Therefore, they have become the most widely used non-ferrous metal structural materials in the aerospace industry.

[0003] To improve the performance of aluminum-copper alloys, a large number of alloying elements are generally added. Taking 205A aluminum-copper alloy as an example, in addition to Cu, it also contains Mn, V, Ti, Zr, Cd, B, and other elements, which easily leads to compositional segregation during production. To avoid defects such as porosity and segregation during casting, only small aluminum melting furnaces of 100kg-300kg are used for production, resulting in low production efficiency. Furthermore, because there are no external aluminum molten metal purification measures, to reduce gas and slag content, most production uses high-purity aluminum ingots with Al 99.95% or higher and low slag content, which are then remelted twice, resulting in high production costs. Therefore, currently, aluminum-copper alloys are produced using high-purity aluminum ingots with Al 99.95% or higher as raw materials through secondary remelting in small aluminum melting furnaces of 100kg-300kg. However, this production method suffers from problems such as easy compositional segregation, high production costs, and low production efficiency.

[0004] Existing technology 1 discloses a method for preparing high-strength aluminum-copper alloys (CN109182804A), specifically revealing that common high-strength cast aluminum alloys are mainly Al-Cu based, which, although possessing high strength, struggle to achieve tensile strengths exceeding 480 MPa and elongation greater than 10%. This invention provides a method for preparing aluminum-copper alloys with superior casting and mechanical properties. By weight percentage, Cu is 4.3%-5.2%; Mn is 0.6%-1.0%; Ti is 0.15%-0.34%; Mg is 0.35%-0.40%; RE is 0.05%-0.15%; Zr is 0.05%-0.2%; Fe <0.2%; Si <0.1%; Zn <0.2%; other impurities <0.5%, with aluminum as the balance. This technical solution produces cast aluminum alloys with superior overall performance and lower material costs.

[0005] The existing technology involves the production of aluminum-copper alloys, but it uses a small furnace and can only produce 100kg. Moreover, it lacks external aluminum liquid purification measures and differs from this patent in terms of raw materials, production equipment, production process, and product quality.

[0006] Existing technology 2 discloses a high-quality, high-strength cast aluminum alloy material and its preparation method (CN105002408A): This invention relates to a high-quality, high-strength cast aluminum alloy material and its preparation method, specifically an aluminum-copper alloy and its preparation method. Its composition, by weight percentage, is 4.5-6.5% copper, 1-1.5% manganese, 0.35-0.65% titanium, 0.4-1.0% magnesium, 0.2-0.5% zirconium, 3-6% rare earth elements (RE), 0.01-0.03% boron, <0.1% silicon, <0.2% zinc, <0.2% iron, with the remaining impurities <0.8%, and aluminum as the balance. By adding manganese, titanium, magnesium, zirconium, and rare earth elements to the aluminum-copper alloy, the castability of the aluminum-copper alloy can be significantly improved, and its ductility can be increased to a certain extent; the electron potential difference between the copper-rich phase and the aluminum matrix is ​​reduced, improving the corrosion resistance of the aluminum-copper alloy; and segregation in the aluminum-copper alloy can be eliminated to a certain extent.

[0007] Existing technology 2 involves the production of aluminum-copper alloys, but it uses a high-frequency vacuum melting furnace, which limits batch production and lacks external aluminum liquid purification measures, resulting in high gas and slag content in the product. Our company uses a dual-chamber furnace with an external aluminum liquid purification system, which can produce about 20 tons per furnace with low gas and slag content.

[0008] Existing technology 3 discloses a casting process for aluminum-copper alloy round ingots (CN104451297A): This invention discloses a casting process for aluminum-copper alloy round ingots. First, low-iron, low-silicon aluminum ingots, aluminum-manganese alloy, aluminum-copper master alloy ingots, aluminum-lead master alloy ingots, and magnesium ingots are selected according to a specific ratio. Then, the selected raw materials are melted at 710-750℃ and thoroughly stirred. Next, a refining agent is added to the melt for refining, controlling the refining time to 10-20 minutes and the temperature to 730-750℃. The refining agent is a sodium-free refining agent. Immediately afterwards, slag is removed and the mixture is kept at a constant temperature and allowed to stand. Then, online refining and degassing are performed. Finally, the melt is filtered and cast at 680-730℃ to obtain the product. This aluminum-copper alloy round ingot casting process can reduce gradual cracking and improve the quality of the castings.

[0009] Existing technology three involves aluminum-copper alloys, but it is produced by remelting low-iron and low-silicon aluminum ingots, which results in high production costs and cannot guarantee the avoidance of compositional segregation during the production process. Summary of the Invention

[0010] The purpose of this invention is to provide a method for producing high-performance aluminum-copper alloys, which directly uses electrolytic aluminum liquid with an Al content of 99.85 or higher. By using the forced stirring action of a dual-chamber furnace in conjunction with a side-wall refining system and an external aluminum liquid purification system, the method not only solves the problems of unstable quality such as component segregation and high gas and slag content, but also significantly improves production efficiency and reduces production costs, making it suitable for mass production.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0012] A method for producing high-performance aluminum-copper alloys, using electrolytic aluminum liquid with a purity of 99.85% or higher as raw material, and employing a double-chamber melting furnace with a sidewall refining system to prepare high-performance aluminum-copper alloy ingots. The method includes the following steps:

[0013] (1) Design the chemical composition of aluminum-copper alloy;

[0014] (2) Raw material preparation: Prepare electrolytic aluminum liquid with an Al content of 99.85% or higher; the raw material sources for copper, aluminum, zirconium, cadmium, titanium, vanadium and manganese are aluminum-copper master alloy, aluminum-zirconium master alloy, aluminum-cadmium master alloy, aluminum-titanium master alloy, aluminum-vanadium master alloy and manganese agent, respectively; prepare fine refining agent;

[0015] (3) Smelting of aluminum-copper alloys:

[0016] After the electrolytic aluminum liquid is fed into the double-chamber melting furnace, the other raw materials (each intermediate alloy) in step (2) are added to the aluminum liquid according to the chemical composition ratio of aluminum-copper alloy. The mechanical pump is turned on to make the aluminum liquid circulate between the heating chamber and the scrap chamber to complete the melting and promote the uniformity of aluminum liquid composition and temperature. Then, the side wall refining system of the double-chamber melting furnace is used to control the temperature at 720-760℃ for refining. After refining, the surface slag is removed cleanly.

[0017] (4) The alloy liquid composition meets the requirements and the temperature is within the range of 720-760℃ for casting; an online wire feeder is used to add a finer agent at the furnace eye to ensure the finer effect to the maximum extent and avoid the aggregation caused by adding a large amount of AlTi5B1 finer agent. Then, the aluminum liquid is degassed and slag removed by the aluminum liquid purification system outside the furnace before casting to obtain aluminum-copper alloy casting ingots or bars.

[0018] In step (1) above, the chemical composition of the aluminum-copper alloy by weight percentage is as follows:

[0019] Fe ≤ 0.40%, Si ≤ 0.25%, Cu: 4.6-5.3%, Mn: 0.3-0.5%, V: 0.05-0.3%, Cd: 0.15-0.25%, Zr: 0.15-0.25%, Ti: 0.15-0.35%, B: 0.005-0.6%, other individual impurities ≤ 0.05%, total impurities ≤ 0.15%, balance Al.

[0020] In step (1) above, the quality of the electrolytic aluminum liquid with an Al content of 99.85% or higher meets the requirements of GB / T 1196-2017 standard; the preferred master alloys are AlCu50 master alloy, AlZr10 master alloy, AlCd10 master alloy, AlTi10 master alloy, and AlV10 master alloy, and the quality of each master alloy meets the requirements of GB / T 27677-2017 standard; the quality of the Mn agent meets the requirements of YS / T492-2021 standard; the refining agent is selected as AlB3 and AlTi5B rod-shaped refining agent, and the quality meets the requirements of GB / T 27677-2017 standard.

[0021] In step (3) above, the dual-chamber melting furnace includes a heating chamber and a scrap chamber. A mechanical pump is connected between the heating chamber and the scrap chamber. The mechanical pump drives the molten aluminum from the molten pool in the heating chamber into the scrap chamber, transferring the energy of the heating chamber to the scrap chamber, so that the temperature of the molten aluminum in the scrap chamber gradually increases, providing the main heat source for the melting of scrap. The molten aluminum in the scrap chamber then returns to the heating chamber, thus completing a molten aluminum circulation process. The forced stirring effect generated by this molten aluminum circulation makes the temperature and chemical composition of the molten aluminum in the pool more uniform.

[0022] In step (3) above, the heating temperature of the heating chamber is 730-760℃ and the refining time is 40-60min.

[0023] In step (4) above, the amount of AlB3 and AlTi5B1 rod-shaped refining agents added is 4-6 kg / tAl.

[0024] In step (4) above, the refining system is connected to the external aluminum liquid purification system. The external aluminum liquid purification system includes a single-stage plate filter, an online refining degassing device, and a double-stage plate filter. After refining, the alloy liquid passes through a single-stage plate filter (filter specification ≥30ppi), an online refining degassing device (degassing efficiency ≥50%), and a double-stage plate filter (filter specification 40ppi or above) in sequence before casting.

[0025] In step (4) above, the temperature of the alloy liquid during casting is 680-700℃. An ingot casting machine or an alloy rod casting machine is selected to produce the corresponding aluminum-copper alloy casting ingots or aluminum-copper alloy rods.

[0026] The aluminum-copper alloy prepared in this invention has a Cu content segregation ≤2%, an online hydrogen content ≤0.10 ml / 100 g Al, and a slag content ≤0.06 mm as determined by PoDFA. 2 / kg.

[0027] The advantages and beneficial effects of this invention are as follows:

[0028] 1. This invention employs a dual-chamber furnace with an external aluminum molten metal purification system to produce high-performance aluminum-copper alloys. It eliminates the need for secondary remelting of high-purity aluminum ingots, directly using electrolytic aluminum molten metal with an Al content of 99.85% or higher. This results in a shorter process, lower production costs, and solves problems such as component segregation, boron aggregation, and high gas and slag content associated with producing high-copper aluminum alloys like ZLD205A in small aluminum melting furnaces. Furthermore, this method can utilize aluminum melting furnaces of 20 tons or more, significantly improving production efficiency compared to the 100-300 kg per batch produced by vacuum melting furnaces and electric furnaces. This method is suitable for industrial-scale mass production.

[0029] 2. This invention employs a dual-chamber furnace aluminum liquid circulation system and a side-wall refining system. The alloy liquid composition meets the requirements, and casting can be carried out within the temperature range of 720-760℃. At the furnace opening, AlB3 and AlTiB refining agents are added by online wire feeding using a double-disc system. After the furnace opening is opened, the aluminum liquid passes through a single-stage plate filter, and then undergoes online refining and double-stage plate filtration for degassing and slag removal, ensuring an online refining degassing efficiency of over 50% and a filter sheet specification of ≥30ppi. The casting temperature is 680-700℃, and the aluminum liquid enters the ingot casting machine or alloy rod casting machine, producing approximately 15kg of aluminum-copper alloy casting ingots or aluminum rods. Detailed Implementation

[0030] To further understand the present invention, the present invention is described below with reference to examples. However, the examples are only for further illustrating the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention.

[0031] This invention provides a process for producing high-performance aluminum-copper cast aluminum alloys using a double-chamber furnace equipped with sidewall refining equipment, applicable to the industrial mass production of aluminum-copper cast aluminum alloys within the following composition range.

[0032] The alloy casting composition (wt.%) is as follows: Fe≤0.40%, Si≤0.25%, Cu: 4.6-5.3%, Mn: 0.3-0.5%, V: 0.05-0.3%, Cd: 0.15-0.25%, Zr: 0.15-0.25%, Ti: 0.15-0.35%, B: 0.005-0.6%, other individual impurity elements ≤0.05%, total impurities ≤0.15%, and the balance is Al.

[0033] Raw material requirements in the examples: ① Electrolytic aluminum liquid with Al 99.85 or higher, meeting the requirements of GB / T 1196-2017 standard; ② AlCu50 master alloy, meeting the requirements of GB / T 27677-2017 standard; ③ AlZr10 master alloy, meeting the requirements of GB / T 27677-2017 standard; ④ AlCd10 master alloy, meeting the requirements of GB / T 27677-2017 standard; ⑤ AlTi10 master alloy, meeting the requirements of GB / T 27677-2017 standard; ⑥ AlV10 master alloy, meeting the requirements of GB / T 27677-2017 standard; ⑦ Mn agent, meeting the requirements of YS / T 492-2021 standard; ⑧ AlB3 and AlTi5B rod-shaped refining agents, meeting the requirements of GB / T 27677-2017 standard.

[0034] Equipment requirements: The main equipment includes a double-chamber melting furnace and ingot casting machine, online wire feeder, alloy rod casting machine, and online refining equipment with a degassing efficiency of 50% or higher, as well as filter equipment with filter disc specifications ≥30ppi.

[0035] The double-chamber furnace is a traditional reverberatory furnace divided into two chambers, a heating chamber and a scrap chamber, by a partition wall. It is developed based on the side-shaft reverberatory furnace. Its main advantages are low exhaust gas emissions, energy saving, low metal loss, and high production efficiency. It is particularly suitable for the smelting of recycled aluminum. The forced stirring effect generated by the aluminum liquid circulation in the double-chamber furnace makes the temperature and chemical composition of the molten aluminum pool more uniform. It can be used to produce aluminum alloys that are prone to compositional segregation. The production capacity can reach 20 tons or more at a time, and the production efficiency is significantly improved (see: Application of advanced double-chamber furnace in recycled aluminum industry, Special Casting and Nonferrous Metallurgy, 2009, 29(8): 779-780).

[0036] Compared to conventional refining, the sidewall refining system eliminates the need to open the furnace door during refining, reducing labor intensity and heat loss caused by door opening. The stirring action of the dual-chamber furnace circulates the molten aluminum, significantly enhancing the refining effect when combined with sidewall refining.

[0037] The external aluminum liquid purification system includes single-stage plate filtration, double-stage plate filtration, and online degassing and slag removal refining equipment. It further degasses and removes slag from the aluminum liquid that has already undergone in-furnace purification during the production process, improving the cleanliness of the aluminum liquid and significantly enhancing product performance.

[0038] Example:

[0039] After 30,000 kg of aluminum is introduced into the double-chamber furnace, 3,800 kg of AlCu50 master alloy, 780 kg of AlZr10 master alloy, 780 kg of AlCd10 master alloy, 1,000 kg of AlTi10 master alloy, 600 kg of AlV10 master alloy, and 200 kg of 75Mn agent are added. The mechanical stirring pump is turned on to circulate the aluminum liquid. The temperature is controlled to reach 745℃ for side wall refining. After refining, the surface slag is removed cleanly.

[0040] Casting began when the alloy composition met the requirements and the temperature reached 740℃. The double-coil wire feeder was activated, and AlB3 and AlTi5B were added at 5 kg / tAl. After the furnace opening, the molten aluminum passed through a 30 ppi single-stage plate filter, and then through an online refining and degassing device and 40 ppi and 50 ppi dual-stage plate filters for degassing and slag removal. The online refining and degassing efficiency was tested at 58%, and the hydrogen content after online degassing was measured to be 0.089 ml / 100gAl.

[0041] The entire casting and rolling process ensures a casting temperature of 682-695℃, and the ingots are produced in the casting machine to produce aluminum alloy casting ingots weighing about 15kg.

[0042] The final product contains 5.08-5.14% Cu, 0.39-0.40% Mn, 0.13-0.15% V, 0.19-0.20% Cd, 0.18-0.19% Zr, 0.26-0.27% Ti, and 0.02% B. The residue content, measured using PoDFA, is 0.053 mm. 2 / kg. Cu content segregation ≤2%.

Claims

1. A method for producing a high-performance aluminum-copper alloy, characterized in that: This method uses electrolytic aluminum liquid with a purity of 99.85% or higher as raw material and employs a double-chamber melting furnace with a sidewall refining system to prepare high-performance aluminum-copper alloy ingots. The prepared aluminum-copper alloy exhibits Cu segregation ≤2%, online hydrogen content ≤0.10 ml / 100gAl, and slag content ≤0.06 mm as determined by PoDFA. 2 / kg; The chemical composition of this aluminum-copper alloy, by weight percentage, is as follows: Fe ≤ 0.40%, Si ≤ 0.25%, Cu: 4.6-5.3%, Mn: 0.3-0.5%, V: 0.05-0.3%, Cd: 0.15-0.25%, Zr: 0.15-0.25%, Ti: 0.15-0.35%, B: 0.005-0.6%, other individual impurities ≤ 0.05%, total impurities ≤ 0.15%, balance Al; The method includes the following steps: (1) Design the chemical composition of the aluminum-copper alloy; (2) Raw material preparation: Prepare electrolytic aluminum liquid with an Al content of 99.85% or higher; the raw material sources for copper, aluminum, zirconium, cadmium, titanium, vanadium and manganese are aluminum-copper master alloy, aluminum-zirconium master alloy, aluminum-cadmium master alloy, aluminum-titanium master alloy, aluminum-vanadium master alloy and manganese agent, respectively; prepare fine refining agent; (3) Smelting of aluminum-copper alloys: After the electrolytic aluminum liquid is fed into the double-chamber melting furnace, the other raw materials in step (2) are added to the aluminum liquid according to the chemical composition ratio of aluminum-copper alloy. The mechanical pump is turned on to make the aluminum liquid circulate between the heating chamber and the scrap chamber to complete the melting and promote the uniformity of aluminum liquid composition and temperature. Then, the double-chamber melting furnace is used to control the temperature at 720-760℃ for refining. After refining, the surface slag is removed cleanly. (4) The alloy liquid composition meets the requirements and the temperature is within the range of 720-760℃ for casting; an online wire feeder is used to add a refining agent at the furnace eye to ensure the refining effect to the maximum extent and avoid the aggregation caused by adding a large amount of AlTi5B1 refining agent. Then, the aluminum liquid is degassed and slag removed by the aluminum liquid purification system outside the furnace before casting to obtain aluminum-copper alloy casting ingots or bars. The refining system is connected to the external aluminum liquid purification system, which includes a single-stage plate filter, an online refining degassing device, and a double-stage plate filter. After refining, the alloy liquid passes through the single-stage plate filter, the online refining degassing device, and the double-stage plate filter in sequence before casting. The filter element of the single-stage plate filter has a specification of ≥30ppi, the filter element of the double-stage plate filter has a specification of 40ppi or higher, and the degassing efficiency of the online refining degassing device is ≥50%.

2. The method for producing high-performance aluminum-copper alloy according to claim 1, characterized in that: In step (2), the quality of the electrolytic aluminum liquid with an Al content of 99.85% or higher meets the requirements of GB / T 1196-2017 standard; the intermediate alloys are AlCu50 intermediate alloy, AlZr10 intermediate alloy, AlCd10 intermediate alloy, AlTi10 intermediate alloy, and AlV10 intermediate alloy, and the quality of each intermediate alloy meets the requirements of GB / T 27677-2017 standard; the quality of the Mn agent meets the requirements of YS / T 492-2021 standard; the refining agent is selected as AlB3 and AlTi5B rod-shaped refining agent, and the quality meets the requirements of GB / T 27677-2017 standard.

3. The method for producing high-performance aluminum-copper alloy according to claim 1, characterized in that: In step (3), the dual-chamber melting furnace includes a heating chamber and a scrap chamber. A mechanical pump is connected between the heating chamber and the scrap chamber. The mechanical pump drives the molten aluminum from the molten pool in the heating chamber into the scrap chamber, transferring the energy of the heating chamber to the scrap chamber, so that the temperature of the molten aluminum in the scrap chamber gradually increases, providing the main heat source for the melting of scrap. The molten aluminum in the scrap chamber then returns to the heating chamber, thus completing an aluminum molten metal circulation process. The forced stirring effect generated by this aluminum molten metal circulation makes the temperature and chemical composition of the molten aluminum pool more uniform.

4. The method for producing high-performance aluminum-copper alloy according to claim 1 or 3, characterized in that: In step (3), the heating temperature of the heating chamber is 730-760℃ and the refining time is 40-60min.

5. The method for producing high-performance aluminum-copper alloy according to claim 2, characterized in that: In step (4), the amount of AlB3 and AlTi5B1 rod-shaped refining agents added is 4-6 kg / tAl.

6. The method for producing high-performance aluminum-copper alloy according to claim 1, characterized in that: In step (4), an ingot casting machine or an alloy rod casting machine is selected to produce the corresponding aluminum-copper alloy casting ingots or aluminum-copper alloy rods.