Preparation method of 2-series ultrahigh-strength aluminum alloy thick plate for spaceflight

Abstract

The invention discloses a preparation method of a 2-series ultrahigh-strength aluminum alloy thick plate for spaceflight, and relates to a manufacturing method of an aluminum alloy plate. The invention aims to solve the technical problem that 2219 alloy plates produced by the current production process cannot meet the requirements of high strength and oversize specification of current spacecraft aluminum alloys of some models. The method comprises the following steps: 1, smelting to obtain molten aluminum alloy; 2, casting into a cast ingot by adopting a semi-continuous water-cooling casting method; 3, surface treatment and saw cutting; 4, heating treatment; 5, rolling; 6, shearing; 7, solid solution quenching; 8, straightening treatment; 9, stretching; 10, aging treatment; and 11, precisely sawing to obtain a finished plate. By improving the traditional process, the comprehensive performance of the material is remarkably improved, and the method is particularly suitable for manufacturing aircraft structural parts with harsh requirements. The method is used for preparing the 2-series aluminum alloy.

Description

Technical Field

[0001] The invention relates to a method for manufacturing an aluminum alloy plate. Background Art

[0002] As a typical aluminum alloy that can be strengthened by heat treatment, 2XXX series 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 processing performance, high corrosion resistance and toughness. In the manufacture of spacecraft, 2219 aluminum alloy in the 2xxx series is an early and widely used super-hard aluminum alloy, mainly used for spacecraft structural parts, rocket engine nozzles, heat shields, combustion chambers and other parts that need to withstand extremely high temperatures. With the vigorous development of the domestic aerospace industry, the requirements for the size and performance of materials have also increased significantly. The 2219 alloy plates produced according to the previous production process can no longer meet the requirements of high strength and super-large size specifications of some models of spacecraft aluminum alloys today. Summary of the invention

[0003] In order to solve the problem that the 2219 alloy plates produced by the current production process can no longer meet the requirements of high strength and ultra-large size specifications of some types of spacecraft aluminum alloys, the present invention provides a method for preparing 2 series ultra-high strength aluminum alloy thick plates for aerospace use.

[0004] A method for preparing a 2-series ultra-high strength aluminum alloy thick plate for aerospace use is specifically carried out in the following steps:

[0005] 1. According to the mass fraction of elements, 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 element of the impurity alloy is ≤0.05%, the total content of the impurity alloy elements is ≤0.15%, and the balance element is Al. Electrolytic copper, pure aluminum, and intermediate alloy are weighed as raw materials, and the weighed raw materials are smelted at a temperature of 700°C-750°C for 5h-7h to obtain an aluminum alloy melt;

[0006] 2. The aluminum alloy melt produced in step 1 is cast into an ingot by a semi-continuous water-cooled casting method; the casting process parameters are: the casting temperature is controlled to be 690°C to 720°C, the casting speed is 75mm / min to 80mm / min, the liquid level is 60mm to 80mm, and the cooling water pressure is 0.12-0.15MPa;

[0007] 3. Surface treatment is performed on the ingot produced in step 2, and a layer of the entire surface of the ingot is milled, the ingot milling amount is 5mm to 40mm, and then sawing is performed;

[0008] Fourth, place the ingot sawed in step 3 in a heating furnace for heating, set the heating temperature to 490°C to 510°C, and the heating time to 5h to 6h; change the heating temperature to 420°C to 440°C, the heating time to 3h to 5h, and the furnace temperature to 400°C to 430°C;

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

[0010] 6. Cut the long board obtained in step 5 to a fixed length to obtain a rough board;

[0011] 7. Put the rough plate obtained in step 6 into a roller hearth quenching furnace for solution quenching; the solution quenching process is: fixed temperature 535-545°C, heating time 20min-105min, insulation 30min-160min, after the insulation time is over, automatic quenching treatment, quenching transfer time 15s-40s, to obtain the plate;

[0012] 8. Perform a straightening treatment on the plate after quenching in step 7 to obtain a plate;

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

[0014] 10. The plate after stretching in step 9 is subjected to aging treatment. The aging system is as follows: the aging furnace is set to heat at 165°C, the metal temperature is measured to reach a low point of 160°C, and it is maintained for 18 hours;

[0015] 11. Precision sawing is performed on the plate after aging treatment in step 10 to obtain finished plate and complete the preparation.

[0016] The method of the present invention can realize the stable production of ultra-high strength aluminum alloy thick plates of 2219 alloy; the present invention combines actual production and designs a new heat treatment process system for 2219 alloy with a thickness in the range of 25-80 mm, so as to realize that the room temperature mechanical properties of 2219-T62 state aluminum alloy meet the index requirements of tensile strength ≥400 MPa, yield strength ≥285 MPa, and elongation ≥7%.

[0017] Beneficial effects of the present invention:

[0018] The invention determines the ingot heating process, plate solution quenching process and plate aging process of the 2219-T62 alloy between 25 mm and 80 mm.

[0019] The 2219-T62 alloy prepared by the present invention has mechanical properties far exceeding the performance value index requirements of the 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, and after the straightening and stretching processes, the flatness of the prepared plate can also be guaranteed, and 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] The invention discloses a novel method for manufacturing a 2-series ultra-high strength aluminum alloy thick plate for aerospace use. By improving the traditional process, the comprehensive performance of the material is significantly improved, and the method is particularly suitable for manufacturing demanding aircraft structural parts.

[0021] The method of the invention is used for preparing 2 series aluminum alloy. DETAILED DESCRIPTION

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

[0023] 1. According to the mass fraction of elements, 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 element of the impurity alloy is ≤0.05%, the total content of the impurity alloy elements is ≤0.15%, and the balance element is Al. Electrolytic copper, pure aluminum, and intermediate alloy are weighed as raw materials, and the weighed raw materials are smelted at a temperature of 700°C-750°C for 5h-7h to obtain an aluminum alloy melt;

[0024] 2. The aluminum alloy melt produced in step 1 is cast into an ingot by a semi-continuous water-cooled casting method; the casting process parameters are: the casting temperature is controlled to be 690°C to 720°C, the casting speed is 75mm / min to 80mm / min, the liquid level is 60mm to 80mm, and the cooling water pressure is 0.12-0.15MPa;

[0025] 3. Surface treatment is performed on the ingot produced in step 2, and a layer of the entire surface of the ingot is milled, the ingot milling amount is 5mm to 40mm, and then sawing is performed;

[0026] Fourth, place the ingot sawed in step 3 in a heating furnace for heating, set the heating temperature to 490°C to 510°C, and the heating time to 5h to 6h; change the heating temperature to 420°C to 440°C, the heating time to 3h to 5h, and the furnace temperature to 400°C to 430°C;

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

[0028] 6. Cut the long board obtained in step 5 to a fixed length to obtain a rough board;

[0029] 7. Put the rough plate obtained in step 6 into a roller hearth quenching furnace for solution quenching; the solution quenching process is: fixed temperature 535-545°C, heating time 20min-105min, insulation 30min-160min, after the insulation time is over, automatic quenching treatment, quenching transfer time 15s-40s, to obtain the plate;

[0030] 8. Perform a straightening treatment on the plate after quenching in step 7 to obtain a plate;

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

[0032] 10. The plate after stretching in step 9 is subjected to aging treatment. The aging system is as follows: the aging furnace is set to heat at 165°C, the metal temperature is measured to reach a low point of 160°C, and it is maintained for 18 hours;

[0033] 11. Precision sawing is performed on the plate after aging treatment in step 10 to obtain finished plate and complete the preparation.

[0034] Specific implementation method 2: This implementation method is different from specific implementation method 1 in that the smelting process in step 1 is carried out in a dry reverberatory furnace or a medium frequency induction furnace. The rest is the same as specific implementation method 1.

[0035] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that the crystallizer used in step 2 has a thickness of 420 mm and a width of 1620 mm. Other aspects are the same as specific implementation method 1 or 2.

[0036] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the crystallizer used in step 2 has a thickness of 520 mm and a width of 1620 mm. The rest is the same as specific embodiments 1 to 3.

[0037] Specific embodiment 5: This embodiment is different from specific embodiments 1 to 4 in that: the requirements for casting cooling water in step 2 are: the hardness of the casting circulating water is less than 8dH, the pH value is 7-8, the casting water temperature is ≤24°C, the suspended matter is less than 10mg / L, and the solid particle size is less than 1.5mm. The rest is the same as specific embodiments 1 to 4.

[0038] Specific implementation method 6: This implementation method is different from specific implementation methods 1 to 5 in that: the milling amount of the ingot in step 3 is 5 mm to 30 mm. The rest is the same as specific implementation methods 1 to 5.

[0039] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that step 4 uses a pusher type heating furnace or a trolley type heating furnace for heating. The rest is the same as specific embodiments 1 to 6.

[0040] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that step 6 uses heavy shearing or light shearing by a rolling mill to perform the length cutting. The rest is the same as specific embodiments 1 to 7.

[0041] Specific implementation method 9: This implementation method is different from specific implementation methods 1 to 8 in that: in step 6, the length shearing error is controlled to be ≤ 100 mm. The rest is the same as specific implementation methods 1 to 8.

[0042] Specific embodiment 10: This embodiment is different from specific embodiments 1 to 9 in that the step 10 requires the plate temperature to be 160-170°C and maintained for 18 hours. The rest is the same as specific embodiments 1 to 9.

[0043] The content of the present invention is not limited to the content of the above-mentioned embodiments. The combination of one or several specific embodiments can also achieve the purpose of the invention.

[0044] Example:

[0045] A method for preparing a 2-series ultra-high strength aluminum alloy thick plate for aerospace use is specifically carried out in the following steps:

[0046] 1. According to the mass fraction of elements, 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 element of the impurity alloy is ≤0.05%, the total content of the impurity alloy elements is ≤0.15%, and the balance element is Al. Electrolytic copper, pure aluminum, and intermediate alloy are weighed as raw materials, and the weighed raw materials are placed in a dry reverberatory furnace or a medium frequency induction furnace, and smelted at a temperature of 700°C-750°C for 5h-7h to obtain an aluminum alloy melt;

[0047] 2. The aluminum alloy melt produced in step 1 is cast into an ingot by a semi-continuous water-cooled casting method; the casting process parameters are: the casting temperature is controlled to be 700°C, the casting speed is 77mm / min, the liquid level is 70mm, and the 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: the hardness of the circulating water for casting is 6.8dH, the pH value is 7, the casting water temperature is 22°C, the suspended matter is 9.5mg / L, and the solid particle size is 1.4mm;

[0048] 3. Surface treatment is performed on the ingot produced in step 2, and a layer of the entire surface of the ingot is milled, the ingot milling amount is 5mm to 30mm, and then sawing is performed;

[0049] Fourth, place the ingot sawed in step 3 in a pusher heating furnace or a trolley heating furnace for heating, set the heating temperature to 490°C to 510°C, and the heating time to 5h to 6h; change the heating temperature to 420°C to 440°C, the heating time to 3h to 5h, and the furnace temperature to 400°C to 430°C;

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

[0051] 6. The long plate obtained in step 5 is sheared to a fixed length by heavy shearing or light shearing of a rolling mill, and the length shearing error is controlled to be ≤100mm to obtain a rough plate;

[0052] 7. Put the rough plate obtained in step 6 into a roller hearth quenching furnace for solution quenching; the solution quenching process is: fixed temperature 535-545°C, heating time 20min-105min, insulation 30min-160min, after the insulation time is over, automatic quenching treatment, quenching transfer time 15s-40s, to obtain the plate;

[0053] 8. Perform a straightening treatment on the plate after quenching in step 7 to obtain a plate;

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

[0055] 10. The plate stretched in step 9 is subjected to aging treatment. The aging system is as follows: the aging furnace is set to heat at 165°C, the metal temperature is measured to be at a low point of 160°C, and it is maintained for 18 hours; the plate temperature required to be taken out of the furnace is 160-170°C, and it is maintained for 18 hours;

[0056] 11. Precision sawing is performed on the plate after aging treatment in step 10 to obtain finished plate and complete the preparation.

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

[0058] The finished plate 2219-T62 alloy prepared in this embodiment has mechanical properties far exceeding the performance value index requirements of the 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, and after straightening and stretching processes, the flatness of the prepared plate can also be guaranteed, and 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 ultra-high strength aluminum alloy thick plate for aerospace use, characterized in that The method is specifically carried out in the following steps:

1. According to the mass fraction of elements, 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 element of the impurity alloy is ≤0.05%, the total content of the impurity alloy elements is ≤0.15%, and the balance element is Al. Electrolytic copper, pure aluminum, and intermediate alloy are weighed as raw materials, and the weighed raw materials are smelted at a temperature of 700°C-750°C for 5h-7h to obtain an aluminum alloy melt; 2. The aluminum alloy melt produced in step 1 is cast into an ingot by a semi-continuous water-cooled casting method; the casting process parameters are: the casting temperature is controlled to be 690°C to 720°C, the casting speed is 75mm / min to 80mm / min, the liquid level is 60mm to 80mm, and the cooling water pressure is 0.12-0.15MPa; 3. Surface treatment is performed on the ingot produced in step 2, and a layer of the entire surface of the ingot is milled, the ingot milling amount is 5mm to 40mm, and then sawing is performed; Fourth, place the ingot sawed in step 3 in a heating furnace for heating, set the heating temperature to 490°C to 510°C, and the heating time to 5h to 6h; change the heating temperature to 420°C to 440°C, the heating time to 3h to 5h, and the furnace temperature to 400°C to 430°C; 5. rolling the ingot processed in step 4, setting the rolling temperature to 400° C. to 430° C. and the rolling speed to 1.2 m / s to 2.0 m / s to obtain a long plate; 6. Cut the long board obtained in step 5 to a fixed length to obtain a rough board; 7. Put the rough plate obtained in step 6 into a roller hearth quenching furnace for solution quenching; the solution quenching process is: fixed temperature 535-545°C, heating time 20min-105min, insulation 30min-160min, after the insulation time is over, automatic quenching treatment, quenching transfer time 15s-40s, to obtain the plate; 8. Perform a straightening treatment on the plate after quenching in step 7 to obtain a plate; 9. Stretch the plate straightened in step 8, and control the stretching amount to 1.0-1.5%; 10. The plate after stretching in step 9 is subjected to aging treatment. The aging system is as follows: the aging furnace is set to heat at 165°C, the metal temperature is measured to reach a low point of 160°C, and it is maintained for 18 hours; 11. Precision sawing is performed on the plate after aging treatment in step 10 to obtain finished plate and complete the preparation.

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

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

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

6. The method for preparing a 2-series ultra-high strength aluminum alloy thick plate for aerospace use according to claim 1, characterized in that Step 3: The ingot milling amount is 5mm to 30mm.

7. The method for preparing a 2-series ultra-high strength aluminum alloy thick plate for aerospace use according to claim 1, characterized in that Step 4: heating is performed in a pusher type heating furnace or a trolley type heating furnace.

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

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

10. The method for preparing a 2-series ultra-high strength aluminum alloy thick plate for aerospace use according to claim 1, characterized in that Step 10 requires the plate temperature to be 160-170°C and maintained for 18 hours.