Aluminum alloy with high strength, plasticity and extrudability and production process thereof

Abstract

The invention discloses a high-strength plasticity and high-extrudability aluminum alloy and a production process thereof, and belongs to the technical field of aluminum alloy production. The aluminum alloy comprises the following elements in percentage by mass: 0.8-1.4% of Si; 0.8 to 1.4 percent of Mg; 0.20% to 0.70% of Cu; 0.0 to 0.2 percent of Y; 0.0 to 0.2 percent of Er; 0.02 to 0.3 percent of Zr; ti: 0.05 to 0.25%; and the balance of Al and inevitable impurities. By adjusting the content proportional relation of main alloy elements such as Si, Mg and Cu, optimizing the extrusion process and the secondary aging process, properly reducing the total content of the alloy elements, improving the homogenization treatment temperature and time, reducing the extrusion temperature and increasing the dislocation density in an extruded profile matrix, the ductility of the profile can be effectively improved through high-density dislocation, and the tensile strength of the profile is improved. And through solid solution and secondary aging, precipitation of a precipitation phase in a matrix is promoted, growth of the precipitation phase is prevented, and the purpose of improving the plasticity of the alloy is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy production, and specifically relates to a high-strength, plasticity and high-extrudability aluminum alloy and a production process thereof. Background Art

[0002] With the continuous development of my country's high-speed trains, the requirements for the integrated design and lightweight of train bodies are getting higher and higher, and the strength requirements for complex cross-section profiles of the body are also getting higher and higher. "A high-extrudability and high-strength aluminum alloy and its preparation method (CN202210598736.8)" announced an aluminum alloy and production process that takes into account both extrudability and high strength. The tensile strength of the aluminum alloy in this invention can reach 350MPa, the elongation can reach 14%, and the extrudability is better than that of 6005A alloy; "A rare earth aluminum alloy and its preparation method (CN202311836688.2)" announced a new aluminum alloy material with higher strength, which can be used as the body material of the next generation of trains.

[0003] The two alloys disclosed in CN202210598736.8 and CN202311836688.2 have better solved the compatibility problem between strength and extrudability. However, the addition of rare earth Yb to CN202311836688.2 leads to a significant increase in raw material costs, and the elongation of the profile is reduced while the strength is improved. Summary of the invention

[0004] The purpose of the invention is to provide a high-strength, plastic and highly extrudable aluminum alloy with low material cost and improved elongation of aluminum alloy profiles, which can meet the requirements of the rail transit field for the next generation of car body aluminum alloy profiles.

[0005] The technical solution to achieve the above purpose is: a high-strength, plastic and high-extrudability aluminum alloy, characterized in that: in terms of mass percentage, the element composition of the aluminum alloy is: Si: 0.8-1.4%; Mg: 0.8-1.4%; Cu: 0.20-0.70%; Y: 0.0-0.2%; Er: 0.0-0.2%; Zr: 0.02-0.3%; Ti: 0.05-0.25%; the remainder is Al and unavoidable impurities. Furthermore, the sum of the mass percentages of element Y and element Er is ≤0.2%.

[0006] Another object of the present invention is to provide a production process of a high-strength, ductile and highly extrudable aluminum alloy, characterized in that the preparation process comprises the following steps: Step 1: Calculate the mass of each raw material according to the element formula and prepare the raw materials according to the calculation results; Step 2: Put the raw materials into the smelting furnace for smelting, control the smelting temperature between 730℃-760℃, perform refining and slag removal to obtain the set components, and then use argon gas with a purity of 99.9% to blow and refine the aluminum alloy liquid in the smelting furnace for 5-10 minutes to reduce the gas content in the aluminum liquid; Step 3: Perform slow casting at a temperature of 680°C-700°C to obtain cast bars; Step 4: Perform homogenization treatment at a temperature of 550°C-650°C and keep warm for 4-10 hours; Step 5: Preheat the cast rod to between 380°C and 480°C and preheat the extrusion barrel to between 400°C and 460°C; Step 6: After the casting rod and the extrusion barrel are preheated, they are extruded through the extrusion barrel; Step 7: After extrusion molding, solid solution is carried out at a temperature of 530°C-580°C, and the solid solution time is 30~90min; Step 8: Perform secondary aging within 0.5 hours after the end of the solution treatment to obtain the finished aluminum alloy.

[0007] Furthermore, in the extrusion molding process of step six, extrusion molding is adopted, the temperature of the extrusion barrel is set between 410°C and 420°C, the die hole outlet temperature of the extrusion barrel is set to 420-520°C, and air cooling is adopted as the cooling method.

[0008] Furthermore, in step eight, the secondary aging is first carried out at an aging temperature of 120°C-150°C for 1h-5h, and then at an aging temperature of 160°C-200°C for 2h-7h.

[0009] Beneficial effects of the present invention: The present invention adjusts the content ratio of main alloying elements such as Si, Mg, Cu, optimizes the extrusion process and the secondary aging process, appropriately reduces the total content of alloying elements, increases the homogenization treatment temperature and time, reduces the extrusion temperature, and increases the dislocation density in the matrix of the profile after extrusion. The high-density dislocation can effectively improve the elongation of the profile. After solid solution and secondary aging, the precipitation phase in the matrix is ​​promoted to precipitate and the growth of the precipitation phase is prevented, thereby achieving the purpose of improving the plasticity of the alloy.

[0010] Adding a small amount of Er to the alloy of the present invention to replace Yb ​​in CN202311836688.2 can reduce the cost of raw materials without reducing the performance of the alloy.

[0011] The alloy of the present invention has a mechanical property of up to 400 MPa, an elongation of more than 10%, and extrudability similar to that of the 6005A alloy, and is a deformed aluminum alloy with good comprehensive properties. DETAILED DESCRIPTION

[0012] The specific implementation modes of the present invention are further described below in conjunction with examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the protection scope of the present invention. Example 1

[0013] A high-strength, plastic and high-extrudability aluminum alloy, wherein the elements of the aluminum alloy are as follows, by mass percentage: Si: 1.14%; Mg: 1.37%; Cu: 0.43%; Y: 0.16%; Er: 0.02%; Zr: 0.25%; Ti: 0.16%; the remainder is Al and unavoidable impurities.

[0014] In addition, the present invention also provides a production process for the above-mentioned high-strength, plasticity and high-extrudability aluminum alloy, and the preparation process of the aluminum alloy comprises the following steps: Step 1: Calculate the mass of each raw material according to the element formula and prepare the raw materials according to the calculation results; Step 2: Put the raw materials into the smelting furnace for smelting, control the smelting temperature between 730℃-760℃, and perform refining and slag removal to obtain qualified components. Then, use argon gas with a purity of 99.9% to blow and refine the aluminum alloy liquid in the smelting furnace for 5 minutes to reduce the gas content in the aluminum liquid; Step 3: Perform slow casting at a temperature of 685°C to obtain cast bars; Step 4: homogenize at 580°C and keep warm for 8 hours; Step 5: Preheat the cast rod to 420°C before extrusion; Step 6: Preheat the extrusion barrel to 450°C; Step 7: After the preheating of the cast rod and the extrusion barrel is completed, extrusion is started through the extrusion barrel. The temperature of the extrusion barrel is set to 420°C, the temperature of the die hole outlet of the extrusion barrel is between 420-470°C, and the cooling method is air cooling; Step 8: After extrusion deformation, solid solution is carried out, the temperature is set to 560 °C, and the solid solution time is 1 h; Step 9: After the solution treatment is completed, secondary aging is carried out within 0.5 hours. The primary aging temperature is 120°C and the holding time is 3 hours. Then the secondary aging temperature is increased to 180°C and the holding time is 5 hours. Example 2

[0015] A high-strength, plastic and high-extrudability aluminum alloy, wherein the elements of the aluminum alloy are as follows, by mass percentage: Si: 1.05%; Mg: 1.26%; Cu: 0.54%; Y: 0.10%; Er: 0.05%; Zr: 0.17%; Ti: 0.21%; the remainder is Al and unavoidable impurities.

[0016] In addition, the present invention also provides a production process for the above-mentioned high-extrudability medium-strength aluminum alloy, and the preparation process of the aluminum alloy comprises the following steps: Step 1: Calculate the mass of each raw material according to the element formula and prepare the raw materials according to the calculation results; Step 2: Put the raw materials into the smelting furnace for smelting, control the smelting temperature between 730℃-760℃, and perform refining and slag removal to obtain qualified components. Then, use argon gas with a purity of 99.9% to blow and refine the aluminum alloy liquid in the smelting furnace for 5 minutes to reduce the gas content in the aluminum liquid; Step 3: Perform slow casting at a temperature of 685°C to obtain cast bars; Step 4: homogenize at 630°C and keep warm for 8 hours; Step 5: Preheat the cast rod to 450°C before extrusion; Step 6: When the extrusion barrel is preheated to 450°C; Step 7: After the casting rod and the extrusion barrel are preheated, extrusion begins through the extrusion barrel. The temperature of the extrusion barrel is set to 420°C, the temperature of the die hole outlet of the extrusion barrel is between 450-500°C, and air cooling is used for cooling; Step 8: After extrusion deformation, solid solution is carried out, the temperature is set to 550 °C, and the solid solution time is 1 h; Step 9: After the solution treatment is completed, secondary aging is carried out within 0.5 hours. The primary aging temperature is 150°C and the holding time is 2 hours. Then the secondary aging temperature is increased to 170°C and the holding time is 7 hours. Example 3

[0017] A high-strength, plastic and high-extrudability aluminum alloy, wherein the elements of the aluminum alloy are as follows by mass percentage: Si: 0.94%; Mg: 1.13%; Cu: 0.67%; Y: 0.07%; Er: 0.06%; Zr: 0.27%; Ti: 0.23%; the remainder is Al and unavoidable impurities.

[0018] In addition, the present invention also provides a production process for the above-mentioned high-extrudability medium-strength aluminum alloy, and the preparation process of the aluminum alloy comprises the following steps: Step 1: Calculate the mass of each raw material according to the element formula and prepare the raw materials according to the calculation results; Step 2: Put the raw materials into the smelting furnace for smelting, control the smelting temperature between 730℃-760℃, and perform refining and slag removal to obtain qualified components. Then, use argon gas with a purity of 99.9% to blow and refine the aluminum alloy liquid in the smelting furnace for 5 minutes to reduce the gas content in the aluminum liquid; Step 3: Perform slow casting at a temperature of 685°C to obtain cast bars; Step 4: homogenize at 570°C and keep warm for 8 hours; Step 5: Preheat the cast rod to 390°C before extrusion; Step 6: When the extrusion barrel is preheated to 420°C; Step 7: After the casting rod and the extrusion barrel are preheated, extrusion is started through the extrusion barrel. The temperature of the extrusion barrel is set to 420°C, the temperature of the die hole outlet of the extrusion barrel is between 420-450°C, and air cooling is used for cooling; Step 8: After extrusion deformation, solid solution is carried out, the temperature is set to 550 °C, and the solid solution time is 1 h; Step 9: After the solution treatment is completed, secondary aging is carried out within 0.5 hours. The primary aging temperature is 130°C and the holding time is 2 hours. Then the secondary aging temperature is increased to 180°C and the holding time is 5 hours. Example 4

[0019] A high-strength, plastic and high-extrudability aluminum alloy, wherein the elements of the aluminum alloy are as follows by mass percentage: Si: 1.4%; Mg: 0.8%; Cu: 0.7%; Y: 0.2%; Zr: 0.02%; Ti: 0.25%; the remainder is Al and inevitable impurities.

[0020] In addition, the present invention also provides a production process for the above-mentioned high-extrudability medium-strength aluminum alloy, and the preparation process of the aluminum alloy comprises the following steps: Step 1: Calculate the mass of each raw material according to the element formula and prepare the raw materials according to the calculation results; Step 2: Put the raw materials into the smelting furnace for smelting, control the smelting temperature between 730℃-760℃, and perform refining and slag removal to obtain qualified components. Then, use argon gas with a purity of 99.9% to blow and refine the aluminum alloy liquid in the smelting furnace for 5 minutes to reduce the gas content in the aluminum liquid; Step 3: Perform slow casting at a temperature of 680°C to obtain cast bars; Step 4: Perform homogenization treatment at 650°C and keep the temperature for 4 hours; Step 5: Preheat the cast rod to 480°C before extrusion; Step 6: When the extrusion barrel is preheated to 400°C; Step 7: After the casting rod and the extrusion barrel are preheated, extrusion is started through the extrusion barrel. The temperature of the extrusion barrel is set to 420°C, the temperature of the die hole outlet of the extrusion barrel is between 470-520°C, and the cooling method is air cooling; Step 8: After extrusion deformation, solid solution is carried out, the temperature is set to 580 ° C, and the solid solution time is 30 minutes; Step 9: After the solution treatment is completed, secondary aging is carried out within 0.5 hours. The primary aging temperature is 120°C and the holding time is 1 hour. Then the secondary aging temperature is increased to 200°C and the holding time is 5 hours. Example 5

[0021] A high-strength, plastic and high-extrudability aluminum alloy, wherein the elements of the aluminum alloy are as follows by mass percentage: Si: 0.8%; Mg: 1.4%; Cu: 0.2%; Er: 0.2%; Zr: 0.3%; Ti: 0.05%; the remainder is Al and unavoidable impurities.

[0022] In addition, the present invention also provides a production process for the above-mentioned high-extrudability medium-strength aluminum alloy, and the preparation process of the aluminum alloy comprises the following steps: Step 1: Calculate the mass of each raw material according to the element formula and prepare the raw materials according to the calculation results; Step 2: Put the raw materials into the smelting furnace for smelting, control the smelting temperature between 730℃-760℃, and perform refining and slag removal to obtain qualified components. Then, use argon gas with a purity of 99.9% to blow and refine the aluminum alloy liquid in the smelting furnace for 10 minutes to reduce the gas content in the aluminum liquid; Step 3: Slow casting is performed at a temperature of 700°C to obtain cast rods; Step 4: Perform homogenization treatment at a temperature of 550°C and keep the temperature for 10 hours; Step 5: Preheat the cast rod to 380°C before extrusion; Step 6: Preheat the extrusion barrel to 460°C; Step 7: After the casting rod and the extrusion barrel are preheated, extrusion begins. The temperature of the extrusion barrel is set to 410°C, the temperature of the die hole outlet of the extrusion barrel is between 420-450°C, and air cooling is used for cooling; Step 8: After extrusion deformation, solid solution is carried out, the temperature is set to 530 °C, and the solid solution time is 90 minutes; Step 9: After the solution treatment is completed, secondary aging is carried out within 0.5 hours. The primary aging temperature is 120°C and the holding time is 5 hours. Then the secondary aging temperature is increased to 160°C and the holding time is 2 hours.

[0023] Comparative Example 1 A high-strength and high-extrudability aluminum alloy. The element composition of the aluminum alloy product is as follows, by mass percentage: Si: 1.45%; Mg: 1.23%; Cu: 0.57%; Mn: 0.03%; Y: 0.16%; Yb: 0.01%; Zr: 0.21%; Ti: 0.027%; the remainder is Al and unavoidable impurities.

[0024] In addition, the present invention also provides a production process for the above-mentioned high-extrudability medium-strength aluminum alloy, and the preparation process of the aluminum alloy comprises the following steps: Step 1: Prepare the raw materials by calculating the mass of each raw material according to the element formula; Step 2: Put the ingredients into the smelting furnace in turn for smelting, control the temperature of the aluminum liquid between 730℃-760℃, and perform refining and slag removal to obtain qualified components. Then, use argon gas with a purity of 99.9% to blow and refine the aluminum alloy liquid in the smelting furnace for 5 minutes to reduce the gas content in the aluminum liquid; Step 3: Control the casting temperature at 685°C and perform slow casting; Step 4: The homogenization temperature is controlled at 560°C and kept at this temperature for 8 hours; Step 5: Preheat the cast rod to 500°C before extrusion; Step 6: Preheat the mold to 450°C; Step 7: After the preheating of the cast rod and the extrusion barrel is completed, extrusion begins. The temperature of the extrusion barrel is set at 400°C, the temperature of the die hole outlet of the extrusion barrel is between 520-540°C, and air cooling is used for cooling; Step 8: After extrusion deformation, the alloy needs to be dissolved for a short time, the temperature is set to 580 °C, and the solution time is 1 h; Step 9: After the solution treatment is completed, secondary aging is carried out within 0.5 hours, the aging temperature is 110°C, the holding time is 10 hours, and then the temperature is increased to 175°C, and the holding time is 7 hours.

[0025] Comparative Example 2 6082 aluminum alloy, in terms of mass percentage, the element composition of the aluminum alloy product is: Si: 1.23%; Mg: 1.17%; Cu: 0.16%; Mn: 0.680%; Cr: 0.24%; Ti: 0.037%; the remainder is Al and unavoidable impurities.

[0026] In addition, the present invention also provides a production process for the above-mentioned high-extrudability medium-strength aluminum alloy, and the preparation process of the aluminum alloy comprises the following steps: Step 1: Prepare the raw materials by calculating the mass of each raw material according to the element formula; Step 2: Put the ingredients into the smelting furnace in turn for smelting, control the temperature of the aluminum liquid at 730℃-760℃, and perform refining and slag removal to obtain qualified components. Then, use argon gas with a purity of 99.9% to blow and refine the aluminum alloy liquid in the smelting furnace for 5 minutes to reduce the gas content in the aluminum liquid; Step 3: Control the casting temperature at 685°C and perform slow casting; Step 4: The homogenization temperature is set at 580°C and kept at this temperature for 8 hours; Step 5: Preheat the cast rod to 390°C before extrusion; Step 6: Preheat the mold to 420°C; Step 7: After the preheating of the cast rod and the extrusion barrel is completed, extrusion begins. The temperature of the extrusion barrel is set to 420°C, the temperature of the die hole outlet of the extrusion barrel is between 400-450°C, and air cooling is used for cooling; Step 8: After extrusion deformation, the alloy needs to be dissolved for a short time, the temperature is set to 550 ° C, and the solution time is 1 h; Step 9: After the solution treatment, secondary aging is carried out within 0.5 hours, the aging temperature is 130℃, the holding time is 2 hours, and then the temperature is increased to 180℃, the holding time is 5 hours.

[0027] Comparative Example 3 6005A aluminum alloy, in terms of mass percentage, the element composition of the aluminum alloy product is: Si: 0.631%; Mg: 0.555%; Cu: 0.229%; Mn: 0.114%; Cr: 0.142%; Ti: 0.063%; the remainder is Al and unavoidable impurities.

[0028] In addition, the present invention also provides a production process for the above-mentioned high-extrudability medium-strength aluminum alloy, and the preparation process of the aluminum alloy comprises the following steps: Step 1: Prepare the raw materials by calculating the mass of each raw material according to the element formula; Step 2: Put the ingredients into the smelting furnace in turn for smelting, control the temperature of the aluminum liquid at 730℃-760℃, and perform refining and slag removal to obtain qualified components. Then, use argon gas with a purity of 99.9% to blow and refine the aluminum alloy liquid in the smelting furnace for 5 minutes to reduce the gas content in the aluminum liquid; Step 3: Control the casting temperature at 685°C and perform slow casting; Step 4: The homogenization temperature is set at 580°C and kept at this temperature for 8 hours; Step 5: Preheat the cast rod to 390°C before extrusion; Step 6: Preheat the mold to 420°C; Step 7: After the casting rod and the extrusion barrel are preheated, extrusion is started through the extrusion barrel. The temperature of the extrusion barrel is set to 420°C, the temperature of the die hole outlet of the extrusion barrel is between 400-450°C, and the cooling method is air cooling; Step 8: After extrusion deformation, the alloy needs to be dissolved for a short time, the temperature is set to 550 ° C, and the solution time is 1 h; Step 9: After the solution treatment, secondary aging is carried out within 0.5 hours, the aging temperature is 130℃, the holding time is 2 hours, and then the temperature is increased to 180℃, the holding time is 5 hours.

[0029] Performance Testing The aluminum alloy products produced in this embodiment and the comparative example were tested for extrudability and mechanical properties, and the test data obtained are as follows: Table 1 Mechanical properties and peak extrusion pressure of profiles Material Yield strength MPa Tensile strength MPa Elongation at break % Peak extrusion pressure MPa Example 1 379 425 12.5 9.92 Example 2 375 420 12 9.54 Example 3 373 417 15 10.67 Example 4 362 410 11.5 8.76 Example 5 360 408 12.5 10.88 Comparative Example 1 375 415 9.5 7.52 Comparative Example 2 342 376 16 13.47 Comparative Example 3 287 313 18 10.39 As shown in Table 1, compared with the alloy in "A rare earth aluminum alloy and its preparation method (CN202311836688.2)" (Comparative Example 1), the present invention adopts a lower extrusion temperature to effectively improve the elongation of the alloy. Although the peak extrusion pressure has increased to a certain extent, under the same extrusion conditions, it still has better extrudability than Comparative Examples 1 and Comparative Example 2 (6082 aluminum alloy) (the peak extrusion pressure of Comparative Example 1 under the same conditions is 11.74Mpa), and also has advantages over the extrudability of Comparative Example 3 (6005A aluminum alloy).

Claims

1. A high-strength, plastic and highly extrudable aluminum alloy, characterized in that: In terms of mass percentage, the element composition of the aluminum alloy is: Si: 0.8-1.4%; Mg: 0.8-1.4%; Cu: 0.20-0.70%; Y：0.0-0.2％； Er：0.0-0.2％； Zr：0.02-0.3％； Ti: 0.05-0.25%; the balance is Al and inevitable impurities.

2. The high-strength, plasticity and high-extrudability aluminum alloy according to claim 1, characterized in that: The sum of the mass percentages of element Y and element Er is ≤0.2%.

3. The production process of a high-strength, ductile and highly extrudable aluminum alloy according to claim 1, characterized in that: The preparation process comprises the following steps: Step 1: Calculate the mass of each raw material according to the element formula and prepare the raw materials according to the calculation results; Step 2: Put the raw materials into the smelting furnace for smelting, control the smelting temperature between 730℃-760℃, perform refining and slag removal to obtain the set components, and then use argon gas with a purity of 99.9% to blow and refine the aluminum alloy liquid in the smelting furnace for 5-10 minutes to reduce the gas content in the aluminum liquid; Step 3: Perform slow casting at a temperature of 680°C-700°C to obtain cast bars; Step 4: Perform homogenization treatment at a temperature of 550°C-650°C and keep warm for 4-10 hours; Step 5: Preheat the cast rod to between 380°C and 480°C and preheat the extrusion barrel to between 400°C and 460°C; Step 6: After the casting rod and the extrusion barrel are preheated, they are extruded through the extrusion barrel; Step 7: After extrusion molding, solid solution is carried out at a temperature of 530°C-580°C, and the solid solution time is 30~90min; Step 8: Perform secondary aging within 0.5 hours after the end of the solution treatment to obtain the finished aluminum alloy.

4. The production process of a high-strength, ductile and highly extrudable aluminum alloy according to claim 1, characterized in that: In step 6, in the extrusion molding process, the temperature of the extrusion barrel is set between 410°C and 420°C, the die hole outlet temperature of the extrusion barrel is set to 420-520°C, and air cooling is used for cooling.

5. The production process of a high-strength, ductile and highly extrudable aluminum alloy according to claim 1, characterized in that: In step eight, the secondary aging is first carried out at an aging temperature of 120°C-150°C for 1h-5h, and then at an aging temperature of 160°C-200°C for 2h-7h.