Preparation method of 2 series aerospace ultra-high strength aluminum alloy thick plate

Abstract

The application relates to a preparation method of a 2-series aerospace ultra-high-strength aluminum alloy thick plate and relates to an aluminum alloy plate manufacturing method. In order to solve the technical problem that the 2219 alloy plate produced by the current production process cannot meet the requirements of high strength and super-large size specifications of the present part type of spacecraft aluminum alloy, the application provides the following method: one, melting to obtain an aluminum alloy melt; two, adopting a semi-continuous water-cooling casting method to cast into an ingot; three, surface treatment and sawing; four, heating treatment; five, rolling; six, shearing; seven, solid solution quenching; eight, straightening treatment; nine, stretching; ten, aging treatment; and eleven, precise sawing, so that the finished plate is obtained. The application remarkably improves the comprehensive performance of the material by improving the traditional process, and is particularly suitable for manufacturing aircraft structural parts with high requirements. The application is used for preparing a 2-series aluminum alloy.

Description

Technical Field

[0001] This invention relates to a method for manufacturing aluminum alloy sheets. Background Technology

[0002] 2XXX series aluminum alloys, as typical heat-treatable aluminum alloys, are widely used in important industrial fields such as aerospace, military equipment, and marine engineering due to their high specific strength, good hot working properties, high corrosion resistance, and toughness. In spacecraft manufacturing, 2219 aluminum alloy, a relatively early and widely used ultra-hard aluminum alloy, is mainly used for spacecraft structural components, rocket engine nozzles, thermal shields, combustion chambers, and other components requiring extreme temperature resistance. With the rapid development of China's aerospace industry, the requirements for material dimensions and performance have also increased significantly. 2219 alloy sheets produced using previous processes can no longer meet the high-strength, ultra-large size requirements of some current spacecraft models. Summary of the Invention

[0003] In order to address the problem that the 2219 alloy plates produced by current manufacturing processes can no longer meet the requirements of high strength and ultra-large size of aluminum alloys for some current spacecraft models, this invention provides a method for preparing 2-series ultra-high strength aluminum alloy thick plates for aerospace applications.

[0004] A method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate, specifically comprising the following steps:

[0005] I. Based on the element mass fractions of Si: ≤0.2%, Fe: ≤0.3%, Cu: 5.8~6.8%, Mn: 0.2%~0.4%, Mg: ≤0.2%, Zn: ≤0.1%, Ti: ≤0.02~0.1%, V: 0.05~0.15%, Zr: 0.1~0.25%, the content of a single impurity alloy element is ≤0.05%, the total element content of the impurity alloy is ≤0.15%, and the balance element is Al, electrolytic copper, pure aluminum, and intermediate alloy are weighed as raw materials. The weighed raw materials are smelted at a temperature of 700℃~750℃ for 5h~7h to obtain aluminum alloy melt.

[0006] 2. The aluminum alloy melt produced in step 1 is cast into ingots using a semi-continuous water-cooled casting method. The casting process parameters are as follows: the casting temperature is controlled at 690℃~720℃, the casting speed is 75mm / min~80mm / min, the liquid level is 60mm~80mm, and the cooling water pressure is 0.12-0.15MPa.

[0007] 3. The ingots produced in step 2 are surface treated by milling a layer on the entire surface of the ingot, with a milling amount of 5mm to 40mm, and then sawing.

[0008] 4. Place the sawn ingots from step 3 into a heating furnace for heating. Set the heating temperature to 490℃~510℃ and the heating time to 5h~6h. Then set the heating temperature to 420℃~440℃ and the heating time to 3h~5h. The furnace exit temperature should be 400℃~430℃.

[0009] 5. Roll the ingot processed in step 4, setting the rolling temperature to 400℃~430℃ and the rolling speed to 1.2m / s~2.0m / s to obtain a long plate;

[0010] 6. Cut the long board obtained in step 5 to the required length to obtain raw material boards;

[0011] 7. Place the raw material sheet obtained in step 6 into a roller hearth quenching furnace for solution quenching. The solution quenching process is as follows: constant temperature 535~545℃, heating time 20min~105min, holding time 30min~160min, after the holding time is completed, the quenching process is automatically performed, and the quenching transfer time is 15s~40s to obtain the sheet.

[0012] 8. The quenched sheet material from step 7 is straightened once to obtain a sheet;

[0013] 9. Stretch the straightened plate from step 8, controlling the stretching amount to 1.0-1.5%;

[0014] 10. After stretching the sheet in step 9, perform aging treatment. The aging regime is as follows: set the aging furnace to a constant temperature of 165°C, measure the lowest point of the metal temperature to reach 160°C, and maintain this temperature for 18 hours.

[0015] 11. The aging-treated board from step 10 is precisely sawn to obtain the finished board, thus completing the preparation process.

[0016] The method of this invention enables the stable production of ultra-high strength aluminum alloy thick plates of 2219 alloy. Based on actual production, this invention designs a brand-new heat treatment process for 2219 alloy with a thickness range of 25-80mm, so as to achieve the room temperature mechanical properties of 2219-T62 state aluminum alloy with tensile strength ≥400MPa, yield strength ≥285MPa, and elongation ≥7%.

[0017] Beneficial effects of this invention:

[0018] This invention defines the ingot heating process, plate solution quenching process, and plate aging process for 2219-T62 alloy with a thickness of 25mm to 80mm.

[0019] The 2219-T62 alloy produced by this invention has mechanical properties that far exceed the performance requirements of 2219-T6 alloy in the GJB390-2008 standard: tensile strength ≥400MPa, exceeding the standard requirement by 30MPa; yield strength ≥285MPa, exceeding the standard requirement by 50MPa; other indicators also fully meet the standard requirements. Furthermore, the flatness of the produced plates can be guaranteed after straightening and stretching processes. It can be applied to the production of 2219 ultra-high strength aluminum alloy thick plates. The 2219-T62 plates produced by this method effectively balance the matching relationship between mechanical properties and stress corrosion resistance.

[0020] This invention discloses a novel manufacturing method for 2-series ultra-high strength aluminum alloy thick plates for aerospace applications. By improving the traditional process, the comprehensive performance of the material is significantly enhanced, making it particularly suitable for manufacturing demanding aircraft structural components.

[0021] The method of this invention is used to prepare 2-series aluminum alloys. Detailed Implementation

[0022] Specific Implementation Method 1: This implementation method describes a method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate, which is carried out according to the following steps:

[0023] I. Based on the element mass fractions of Si: ≤0.2%, Fe: ≤0.3%, Cu: 5.8~6.8%, Mn: 0.2%~0.4%, Mg: ≤0.2%, Zn: ≤0.1%, Ti: ≤0.02~0.1%, V: 0.05~0.15%, Zr: 0.1~0.25%, the content of a single impurity alloy element is ≤0.05%, the total element content of the impurity alloy is ≤0.15%, and the balance element is Al, electrolytic copper, pure aluminum, and intermediate alloy are weighed as raw materials. The weighed raw materials are smelted at a temperature of 700℃~750℃ for 5h~7h to obtain aluminum alloy melt.

[0024] 2. The aluminum alloy melt produced in step 1 is cast into ingots using a semi-continuous water-cooled casting method. The casting process parameters are as follows: the casting temperature is controlled at 690℃~720℃, the casting speed is 75mm / min~80mm / min, the liquid level is 60mm~80mm, and the cooling water pressure is 0.12-0.15MPa.

[0025] 3. The ingots produced in step 2 are surface treated by milling a layer on the entire surface of the ingot, with a milling amount of 5mm to 40mm, and then sawing.

[0026] 4. Place the sawn ingots from step 3 into a heating furnace for heating. Set the heating temperature to 490℃~510℃ and the heating time to 5h~6h. Then set the heating temperature to 420℃~440℃ and the heating time to 3h~5h. The furnace exit temperature should be 400℃~430℃.

[0027] 5. Roll the ingot processed in step 4, setting the rolling temperature to 400℃~430℃ and the rolling speed to 1.2m / s~2.0m / s to obtain a long plate;

[0028] 6. Cut the long board obtained in step 5 to the required length to obtain raw material boards;

[0029] 7. Place the raw material sheet obtained in step 6 into a roller hearth quenching furnace for solution quenching. The solution quenching process is as follows: constant temperature 535~545℃, heating time 20min~105min, holding time 30min~160min, after the holding time is completed, the quenching process is automatically performed, and the quenching transfer time is 15s~40s to obtain the sheet.

[0030] 8. The quenched sheet material from step 7 is straightened once to obtain a sheet;

[0031] 9. Stretch the straightened plate from step 8, controlling the stretching amount to 1.0-1.5%;

[0032] 10. After stretching the sheet in step 9, perform aging treatment. The aging regime is as follows: set the aging furnace to a constant temperature of 165°C, measure the lowest point of the metal temperature to reach 160°C, and maintain this temperature for 18 hours.

[0033] 11. The aging-treated board from step 10 is precisely sawn to obtain the finished board, thus completing the preparation process.

[0034] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the melting process in step one is carried out in a dry reverberatory furnace or a medium-frequency induction furnace. Everything else is the same as in Specific Implementation Method One.

[0035] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the crystallizer used in step two has a thickness of 420 mm and a width of 1620 mm. Everything else is the same as in Specific Implementation Method One or Two.

[0036] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the crystallizer used in step two has a thickness of 520 mm and a width of 1620 mm. Everything else is the same as in Specific Implementation Methods One to Three.

[0037] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the requirements for the casting cooling water in step two are: casting circulating water hardness < 8dH, pH value 7-8, casting water temperature ≤ 24℃, suspended solids < 10mg / L, and solid particle size < 1.5mm. All other requirements are the same as in Specific Implementation Methods One to Four.

[0038] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the milling amount of the ingot in step three is 5mm to 30mm. Everything else is the same as in Specific Implementation Methods One to Five.

[0039] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that step four uses a pusher-type or bogie-type heating furnace for heating. Everything else is the same as in Specific Implementation Methods One to Six.

[0040] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that step six involves using a rolling mill for heavy or light shearing to cut the material to a fixed length. Everything else is the same as in Specific Implementation Methods One to Seven.

[0041] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: in step six, the length shearing error is controlled to be ≤100mm. Everything else is the same as in Specific Implementation Methods One to Eight.

[0042] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that: Step Ten requires the plate temperature to be 160-170℃ after exiting the furnace, and it should be maintained for 18 hours before exiting. Everything else is the same as in Specific Implementation Methods One to Nine.

[0043] The scope of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.

[0044] Example:

[0045] A method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate, specifically comprising the following steps:

[0046] I. Based on the element mass fractions of Si: ≤0.2%, Fe: ≤0.3%, Cu: 5.8~6.8%, Mn: 0.2%~0.4%, Mg: ≤0.2%, Zn: ≤0.1%, Ti: ≤0.02~0.1%, V: 0.05~0.15%, Zr: 0.1~0.25%, the content of a single impurity alloy element is ≤0.05%, the total element content of the impurity alloy is ≤0.15%, and the balance element is Al, electrolytic copper, pure aluminum, and intermediate alloy are weighed as raw materials. The weighed raw materials are placed in a dry reverberatory furnace or medium-frequency induction furnace and smelted at a temperature of 700℃~750℃ for 5h~7h to obtain aluminum alloy melt.

[0047] II. The aluminum alloy molten liquid produced in step one is cast into ingots using a semi-continuous water-cooled casting method. The casting process parameters are as follows: casting temperature is controlled at 700℃, casting speed is 77mm / min, liquid level is 70mm, and cooling water pressure is 0.12-0.15MPa. The thickness of the crystallizer is 420mm and the width is 1620mm. The requirements for cooling water are as follows: hardness of the circulating water for casting is 6.8dH, pH value is 7, casting water temperature is 22℃, suspended solids are 9.5mg / L, and solid particle size is 1.4mm.

[0048] 3. The ingots produced in step 2 are surface treated by milling a layer on the entire surface of the ingot, with a milling amount of 5mm to 30mm, and then sawing.

[0049] 4. Place the sawn ingots from step 3 into a pusher furnace or a trolley furnace for heating. Set the heating temperature to 490℃~510℃ and the heating time to 5h~6h. Alternatively, set the heating temperature to 420℃~440℃, the heating time to 3h~5h, and the furnace exit temperature to 400℃~430℃.

[0050] 5. Roll the ingot processed in step 4, setting the rolling temperature to 400℃~430℃ and the rolling speed to 1.2m / s~2.0m / s to obtain a long plate;

[0051] 6. The long plate obtained in step 5 is cut to length using a rolling mill with heavy or light shearing, and the length cutting error is controlled to be ≤100mm to obtain the raw plate.

[0052] 7. Place the raw material sheet obtained in step 6 into a roller hearth quenching furnace for solution quenching. The solution quenching process is as follows: constant temperature 535~545℃, heating time 20min~105min, holding time 30min~160min, after the holding time is completed, the quenching process is automatically performed, and the quenching transfer time is 15s~40s to obtain the sheet.

[0053] 8. The quenched sheet material from step 7 is straightened once to obtain a sheet;

[0054] 9. Stretch the straightened plate from step 8, controlling the stretching amount to 1.0-1.5%;

[0055] 10. After stretching in step nine, the sheet is subjected to aging treatment. The aging regime is as follows: set the heating temperature of the aging furnace to 165℃, measure the lowest point of the metal temperature to 160℃, and maintain it for 18 hours; the sheet temperature is required to be 160-170℃ when it is taken out of the furnace, and it is maintained for 18 hours before being taken out of the furnace.

[0056] 11. The aging-treated board from step 10 is precisely sawn to obtain the finished board, thus completing the preparation process.

[0057] Mechanical tests were conducted on the 2-series aerospace ultra-high strength aluminum alloy thick plate prepared in this embodiment. The tensile strength reached 450.57 MPa and the yield strength reached 321.17 MPa. In contrast, the tensile strength of the 2219-T62 plate produced by the original production process was 401.89 MPa and the yield strength was 270.38 MPa. It can be seen that the mechanical properties of the 2219-T62 alloy in the finished plate prepared by this invention are greatly improved.

[0058] The finished 2219-T62 alloy plate prepared in this embodiment has mechanical properties that far exceed the performance requirements of 2219-T6 alloy in GJB390-2008 standard: tensile strength ≥400MPa, exceeding the standard requirement by 30MPa; yield strength ≥285MPa, exceeding the standard requirement by 50MPa; other indicators also fully meet the standard requirements. Furthermore, the flatness of the plate obtained after straightening and stretching processes can be guaranteed. It can be applied to the production of 2219 ultra-high strength aluminum alloy thick plates. The 2219-T62 plate produced by this method effectively balances the matching relationship between mechanical properties and stress corrosion resistance.

Claims

1. A method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate, characterized in that... This method is specifically carried out in the following steps: I. Based on the element mass fractions as follows: Si: ≤0.2%, Fe: ≤0.3%, Cu: 5.8~6.8%, Mn: 0.2%~0.4%, Mg: ≤0.2%, Zn: ≤0.1%, Ti: ≤0.02~0.1%, V: 0.05~0.15%, Zr: 0.1~0.25%, the content of a single impurity alloy element is ≤0.05%, the total element content of the impurity alloy is ≤0.15%, and the balance element is Al, electrolytic copper, pure aluminum, and intermediate alloy are weighed as raw materials. The weighed raw materials are smelted at a temperature of 700℃~750℃ for 5h~7h to obtain aluminum alloy melt; 2. The aluminum alloy melt produced in step 1 is cast into ingots using a semi-continuous water-cooled casting method. The casting process parameters are as follows: the casting temperature is controlled at 690℃~720℃, the casting speed is 75mm / min~80mm / min, the liquid level is 60mm~80mm, and the cooling water pressure is 0.12-0.15MPa.

3. The ingots produced in step 2 are surface treated by milling a layer on the entire surface of the ingot, with a milling amount of 5mm to 40mm, and then sawing.

4. Place the sawn ingots from step 3 into a heating furnace for heating. Set the heating temperature to 490℃~510℃ and the heating time to 5h~6h. Then set the heating temperature to 420℃~440℃ and the heating time to 3h~5h. The furnace exit temperature should be 400℃~430℃.

5. Roll the ingot processed in step 4, setting the rolling temperature to 400℃~430℃ and the rolling speed to 1.2m / s~2.0m / s to obtain a long plate; 6. Cut the long board obtained in step 5 to the required length to obtain raw material boards; 7. Place the raw material sheet obtained in step 6 into a roller hearth quenching furnace for solution quenching. The solution quenching process is as follows: constant temperature 535~545℃, heating time 20min~105min, holding time 30min~160min. After the holding time is over, the quenching process is automatically performed. The quenching transfer time is 15s~40s to obtain the sheet.

8. The quenched sheet material from step 7 is straightened once to obtain a sheet; 9. Stretch the straightened plate from step 8, controlling the stretching amount to 1.0~1.5%; 10. After stretching the sheet in step 9, perform aging treatment. The aging regime is as follows: set the aging furnace to a constant temperature of 165°C, measure the lowest point of the metal temperature to reach 160°C, and maintain this temperature for 18 hours.

11. The aging-treated board sheet from step 10 is precision sawed to obtain the finished board, thus completing the preparation process; the thickness of the finished board is 25mm to 80mm. Step 10 requires the plate temperature to be 160-170℃ after exiting the furnace, and it should be maintained for 18 hours before exiting the furnace.

2. The method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate according to claim 1, characterized in that... Step one, the smelting process, is carried out in a dry reverberatory furnace or a medium-frequency induction furnace.

3. The method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate according to claim 1, characterized in that... The crystallizer used in step two has a thickness of 420 mm and a width of 1620 mm.

4. The method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate according to claim 1, characterized in that... The crystallizer used in step two has a thickness of 520 mm and a width of 1620 mm.

5. The method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate according to claim 1, characterized in that... The requirements for casting cooling water in step two are as follows: the hardness of the circulating water for casting is <8dH, the pH value is 7-8, the casting water temperature is ≤24℃, the suspended solids are <10mg / L, and the solid particle size is <1.5mm.

6. The method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate according to claim 1, characterized in that... Step 3: Milling the ingot surface area by 5mm to 30mm.

7. The method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate according to claim 1, characterized in that... Step four involves heating using a pusher-type or bogie-type heating furnace.

8. The method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate according to claim 1, characterized in that... Step six involves using a rolling mill for heavy or light shearing to cut the material to the required length.

9. The method for preparing a 2-series aerospace ultra-high strength aluminum alloy thick plate according to claim 1, characterized in that... Step 6: Control the length shearing error to ≤100mm.