A method for preparing an as-received alclad sheet of high-strength damage-tolerant Al-Zn-Mg-Cu aluminum alloy

Abstract

A method for preparing high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet. It belongs to the field of clad aluminum sheet preparation. The method includes: weighing materials; melting to obtain aluminum alloy melt; converter; two-stage degassing and filtration; casting; ingot homogenization annealing, milling, sawing, skin welding, hot finishing rolling, cold rolling; finished product annealing; roll straightening, finished product shearing or sawing. The high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet of this invention has a service condition of T62 K... app The value can reach 60 MPa·m 1 / 2 ~80MPa·m 1 / 2 With a strength Cv value of 1% to 2.0%, the basic properties and damage tolerance properties meet the product standard requirements. It has the characteristics of high strength and high damage tolerance, which solves the problem of industrial preparation of this O-state thin plate. It can provide a new material option for high strength and damage tolerance aluminum alloy O-state thin plates for the frame of a large civil aircraft.

Description

Technical Field

[0001] This invention belongs to the field of aluminum-clad sheet preparation, specifically relating to a method for preparing a high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state aluminum-clad sheet. Background Technology

[0002] With the continuous development of aluminum alloy applications in the aerospace field, higher requirements are being placed on the performance of Al-Zn-Mg-Cu aluminum alloys, especially for large civil aircraft. Due to the integration and enlargement of load-bearing components, fatigue damage to materials poses a significant threat to the airworthiness of the structure. This places higher demands on the basic performance and damage tolerance of Al-Zn-Mg-Cu aluminum alloy O-tempered aluminum sheets. Currently, there is a lack of material-related performance data and material stability assessments according to the design and airworthiness requirements of large civil aircraft. Therefore, it is urgent to develop high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-tempered aluminum sheets that meet the airworthiness requirements of large civil aircraft. Furthermore, it is crucial to solve the technical challenges of coordinating and controlling the alloy composition, heat treatment process, and performance of Al-Zn-Mg-Cu aluminum alloy O-tempered aluminum sheets for large civil aircraft, thereby improving the product quality of Al-Zn-Mg-Cu aluminum alloy O-tempered aluminum sheets for civil aircraft. Summary of the Invention

[0003] The purpose of this invention is to solve the above-mentioned technical problems and to provide a method for preparing high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet.

[0004] A method for preparing high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet, comprising the following steps:

[0005] I. Weigh out aluminum ingots, magnesium ingots, zinc ingots, aluminum-copper master alloys, and aluminum-titanium master alloys for remelting according to the element weight percentages: Si≤0.50%, Fe≤0.30%, Cu:1.4%~1.8%, Mn≤0.10%, Mg:2.3%~2.7%, Zn:5.40%~5.80%, Ti:0.02%~0.04%, single impurity≤0.05%, total impurities≤0.15%, and balance Al.

[0006] 2. Add the aluminum ingots, aluminum-copper master alloy and aluminum-titanium master alloy weighed in step 1 to the melting furnace for melting. After partial melting, add zinc ingots to the melt, then add magnesium ingots. Let it sit for 10-30 minutes, stir, and cover with No. 2 solvent. When the melt temperature is 730℃-760℃, transfer it to the holding furnace to obtain aluminum alloy melt.

[0007] 3. The above aluminum alloy melt is passed through a mixture of Ar-Cl2 gas and Ar gas for two-stage degassing, and then filtered using 30ppi+50ppi filter sheets. When the melt temperature is 700℃~730℃, AlTi5B1 wire is added online, and then casting is carried out. At the same time, hydrogen content is measured at the flow channel. The hydrogen content is ≤0.10ml / 100gAl until the casting is completed, and the alloy ingot is obtained.

[0008] 4. The above alloy ingots are heated at 460℃~470℃ for 41h~47h to complete the homogenization annealing treatment of the ingots. Then, they are milled, sawed, and welded together. The hot finishing rolling temperature is 290℃~330℃. Then, they are cold rolled to Al-Zn-Mg-Cu aluminum alloy sheets with a finished thickness of 1.6mm~6.35mm.

[0009] 5. The above-mentioned Al-Zn-Mg-Cu aluminum alloy sheet is subjected to finished product annealing. The first stage temperature is 399℃~409℃, held for 2h~3h, then cooled to 180℃~210℃, then heated to 227℃~237℃, held for 4h, cooled in the furnace for 1h~2h, and then removed from the furnace and air-cooled to obtain the finished annealed sheet.

[0010] VI. The above-mentioned finished annealed sheet is subjected to roll straightening, finished product shearing or sawing to obtain a high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet, thus completing the preparation method described above.

[0011] Furthermore, the melting temperature in step two is 720℃~760℃.

[0012] Furthermore, the amount of solvent #2 used in step two accounts for 0.1% to 0.3% of the total mass of the melt.

[0013] Furthermore, the gas flow rate of the two-stage degassing process in step two is 0.4 m³ / s. 3 / h~1.0m 3 / h, time is 30-50min.

[0014] Furthermore, the Ar-Cl2 mixed gas mentioned in step three is a mixture of 95% high-purity argon and 5% high-purity chlorine.

[0015] Furthermore, the amount of AlTi5B1 wire used in step three is 0.005 wt% of the melt with Ti element added.

[0016] Furthermore, the speed at which the AlTi5B1 wire is inserted in step three is 520 mm / min.

[0017] Furthermore, in step four, the leather welding process involves using 7072 alloy as the aluminum cladding material and welding via riveting.

[0018] Advantages of this invention:

[0019] 1. The high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad sheet prepared in this invention meets the product standard requirements in terms of its basic properties and damage tolerance performance, exhibiting high strength and high damage tolerance characteristics. This invention solves the problem of industrial-scale preparation of damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state sheets, and addresses the technical challenge of coordinating and controlling the alloy composition, heat treatment process, and performance of Al-Zn-Mg-Cu aluminum alloy O-state sheets for large civil aircraft. It improves the product quality of Al-Zn-Mg-Cu aluminum alloy O-state sheets for civil aircraft and can provide a new material option for high-strength, damage-tolerant aluminum alloy O-state sheets used in the frame of a large civil aircraft.

[0020] 2. The Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet prepared by this invention has a K content in the T62 state during its service life. app The value can reach 60 MPa·m 1 / 2 ~80MPa·m 1 / 2 The strength Cv value is between 1% and 2.0%.

[0021] 3. In this invention, the Al-Zn-Mg-Cu aluminum alloy O-state cladding sheet alloy ingot is cast using a semi-continuous casting method. During the casting process, online double-stage degassing and double-stage filtration are employed to ensure that high metallurgical quality cladding sheet ingots are obtained, thus providing a guarantee for subsequent sheet preparation and performance stability.

[0022] This invention is applicable to the preparation of high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheets. Attached Figure Description

[0023] Figure 1 Polarized microstructure of O-state clad aluminum sheet of medium-high strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy;

[0024] Figure 2 EBSD microstructure of Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet in T62 state for implementation of medium-high strength and damage tolerance;

[0025] Figure 3 SEM images of T62 state aluminum-clad sheets of Al-Zn-Mg-Cu aluminum alloy in O state for implementation of medium-high strength and damage tolerance. Detailed Implementation

[0026] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0027] Specific Implementation Method 1: This implementation method provides a method for preparing a high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet, which is carried out according to the following steps:

[0028] I. Weigh out aluminum ingots, magnesium ingots, zinc ingots, aluminum-copper master alloys, and aluminum-titanium master alloys for remelting according to the element weight percentages: Si≤0.50%, Fe≤0.30%, Cu:1.4%~1.8%, Mn≤0.10%, Mg:2.3%~2.7%, Zn:5.40%~5.80%, Ti:0.02%~0.04%, single impurity≤0.05%, total impurities≤0.15%, and balance Al.

[0029] 2. Add the aluminum ingots, aluminum-copper master alloy and aluminum-titanium master alloy weighed in step 1 to the melting furnace for melting. After partial melting, add zinc ingots to the melt, then add magnesium ingots. Let it sit for 10-30 minutes, stir, and cover with No. 2 solvent. When the melt temperature is 730℃-760℃, transfer it to the holding furnace to obtain aluminum alloy melt.

[0030] 3. The above aluminum alloy melt is passed through Ar-Cl2 mixed gas and HD2000 for two-stage degassing, and then filtered using 30ppi+50ppi filter sheets. When the melt temperature is 700℃~730℃, AlTi5B1 wire is added online, and then casting is carried out. At the same time, hydrogen is measured at the flow channel. The hydrogen content is ≤0.10ml / 100gAl until the casting is completed, and the alloy ingot is obtained.

[0031] 4. The above alloy ingots are heated at 460℃~470℃ for 41h~47h to complete the homogenization annealing treatment of the ingots. Then, they are milled, sawed, and welded together. The hot finishing rolling temperature is 290℃~330℃. Then, they are cold rolled to Al-Zn-Mg-Cu aluminum alloy sheets with a finished thickness of 1.6mm~6.35mm.

[0032] V. The above-mentioned Al-Zn-Mg-Cu aluminum alloy sheet is subjected to finished product annealing. The first stage temperature is 399℃~409℃, held for 2h~3h, then cooled to 180℃~210℃, then heated to 227℃~237℃, held for 4h, cooled in the furnace for 1h~2h, and then air-cooled to obtain the finished annealed sheet.

[0033] VI. The above-mentioned finished annealed sheet is subjected to roll straightening, finished product shearing or sawing to obtain a high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet, thus completing the preparation method described above.

[0034] In step two of this embodiment, after adding magnesium ingots, it is necessary to ensure that the magnesium ingots do not protrude from the liquid surface.

[0035] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that, in step one, the elemental weight percentages are as follows: Si ≤ 0.50%, Fe ≤ 0.30%, Cu: 1.6%, Mn ≤ 0.10%, Mg: 2.5%, Zn: 5.60%, Ti: 0.03%, single impurity ≤ 0.05%, total impurities ≤ 0.15%, and the balance is Al. Other steps and parameters are the same as in Specific Implementation Method One.

[0036] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One in that the melting temperature in step two is 720℃~760℃. Other steps and parameters are the same as in Specific Implementation Method One.

[0037] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method One in that the amount of solvent #2 used in step two accounts for 0.1% to 0.3% of the total mass of the melt. Other steps and parameters are the same as in Specific Implementation Method One.

[0038] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method One in that the gas flow rate of the two-stage degassing process in step two is 0.4 m³ / s. 3 / h~1.0m 3 / h, time is 30-50min. Other steps and parameters are the same as in Specific Implementation Method 1.

[0039] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method One in that the Ar-Cl2 mixed gas mentioned in step three is a mixture of 95% high-purity argon and 5% high-purity chlorine. Other steps and parameters are the same as in Specific Implementation Method One.

[0040] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method One in that the amount of AlTi5B1 wire used in step three is 0.005 wt% of the melt containing Ti element. Other steps and parameters are the same as in Specific Implementation Method One.

[0041] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method One in that the speed at which the AlTi5B1 wire is inserted in step three is 520 mm / min. Other steps and parameters are the same as in Specific Implementation Method One.

[0042] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method One in that, in step four, the alloy ingot is heated at 465°C for 45 hours. All other steps and parameters are the same as in Specific Implementation Method One.

[0043] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method One in that the leather welding process in step four uses 7072 alloy as the aluminum cladding material; the welding is done by riveting. Other steps and parameters are the same as in Specific Implementation Method One.

[0044] The beneficial effects of the present invention are verified through the following embodiments:

[0045] Example:

[0046] A method for preparing high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet, comprising the following steps:

[0047] I. Weigh out aluminum ingots, magnesium ingots, zinc ingots, aluminum-copper master alloys, and aluminum-titanium master alloys for remelting according to the element weight percentages: Si≤0.50%, Fe≤0.30%, Cu:1.6%, Mn≤0.10%, Mg:2.5%, Zn:5.60%, Ti:0.03%, single impurity≤0.05%, total impurities≤0.15%, and balance Al.

[0048] 2. Add the aluminum ingots, aluminum-copper master alloy and aluminum-titanium master alloy weighed in step 1 to the melting furnace for melting. After partial melting, add zinc ingots to the melt. After melting, add magnesium ingots. Let it sit for 30 minutes. After stirring, cover with solvent #2. When the melt temperature is 750℃, transfer to the holding furnace to obtain aluminum alloy melt.

[0049] 3. The above aluminum alloy melt is passed through a mixture of Ar-Cl2 gas and Ar gas for two-stage degassing, and then filtered using 30ppi+50ppi filter sheets. When the melt temperature is 720℃, AlTi5B1 wire is added online, and then casting is carried out. At the same time, hydrogen content is measured at the flow channel. The hydrogen content is ≤0.10ml / 100gAl until the casting is completed, and the alloy ingot is obtained.

[0050] 4. The above alloy ingots were heated at 460℃ for 45 hours to complete the homogenization annealing treatment of the ingots. Then, milling, sawing, and skin welding were carried out. The hot finishing rolling temperature was 300℃, and then cold rolling was performed to produce Al-Zn-Mg-Cu aluminum alloy sheet with a finished thickness of 3.25mm.

[0051] 5. The above-mentioned Al-Zn-Mg-Cu aluminum alloy sheet is subjected to finished product annealing. The first stage temperature is 402℃, held for 2.5h, cooled to 200℃, then heated to 230℃, held for 4h, cooled in the furnace for 2h, and then air-cooled to obtain the finished annealed sheet.

[0052] VI. The above-mentioned finished annealed sheet is subjected to roll straightening, finished product shearing or sawing to obtain a high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet, thus completing the preparation method described above.

[0053] The melting temperature described in step two of this embodiment is 740°C.

[0054] In step two of this embodiment, the amount of solvent #2 accounts for 0.2% of the total mass of the melt.

[0055] In step two of this embodiment, the gas flow rate for the two-stage degassing process is 0.8 m³ / s. 3 / h, time is 40min.

[0056] In step three of this embodiment, the Ar-Cl2 mixed gas is a mixture of 95% high-purity argon and 5% high-purity chlorine.

[0057] The amount of AlTi5B1 wire used in step three of this embodiment is 0.005 wt% of the melt with Ti element added.

[0058] In step three of this embodiment, the speed at which the AlTi5B1 wire is inserted is 520 mm / min.

[0059] In step four of this embodiment, the leather welding process is as follows: 7072 alloy is used as the aluminum cladding material; the welding is done by riveting.

[0060] The high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet obtained in this embodiment was sampled and subjected to T62 heat treatment response test. The solution treatment temperature was 463℃~469℃, the holding time was 30min~55min, the aging temperature was 116℃~126℃, and the holding time was 23h~25h.

[0061] The performance of the samples tested in the above heat treatment response test was examined, and the K value in the T62 state was determined. app The value can reach 60 MPa·m 1 / 2 ~80MPa·m 1 / 2 With a strength Cv value between 1% and 2.0%, and after passing the test, the high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state thin sheet prepared in this embodiment can be packaged.

[0062] The polarimetric microstructure of the high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad sheet obtained in this embodiment (see...) Figure 1 As can be seen, its grains are recrystallized, which provides a structural guarantee for subsequent thin plate deformation treatment.

[0063] The high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad sheet obtained in this embodiment has an EBSD microstructure in the T62 state (see...). Figure 2 As can be seen, the T62 state grains are fully recrystallized and the average grain size is about 28.3 μm, which ensures that it has good plasticity.

[0064] The high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad sheet obtained in this embodiment has a SEM image in the T62 state (see...). Figure 3 As can be seen, after the O-state thin plate undergoes heat treatment response treatment (T62 state), almost all the internal reinforcement is dissolved back into the matrix, which ensures the improvement of the plate strength.

Claims

1. A method for preparing a high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet, characterized in that... It proceeds in the following steps: I. Weigh out aluminum ingots, magnesium ingots, zinc ingots, aluminum-copper master alloys, and aluminum-titanium master alloys for remelting according to the element weight percentages: Si≤0.50%, Fe≤0.30%, Cu:1.4%~1.8%, Mn≤0.10%, Mg:2.3%~2.7%, Zn:5.40%~5.80%, Ti:0.02%~0.04%, single impurity≤0.05%, total impurities≤0.15%, and balance Al.

2. Add the aluminum ingots, aluminum-copper master alloy and aluminum-titanium master alloy weighed in step 1 to the melting furnace for melting. After partial melting, add zinc ingots to the melt, and then add magnesium ingots. Let it sit for 10-30 minutes, stir, and cover with No. 2 solvent. When the melt temperature is 730℃~760℃, transfer it to the holding furnace to obtain aluminum alloy melt.

3. The above aluminum alloy melt is passed through a mixture of Ar-Cl2 gas and Ar gas for two-stage degassing, and then filtered using 30ppi+50ppi filter sheets. When the melt temperature is 700℃~730℃, AlTi5B1 wire is added online, and then casting is carried out. At the same time, hydrogen content is measured at the flow channel. The hydrogen content is ≤0.10mL / 100gAl until the casting is completed, and the alloy ingot is obtained.

4. The above alloy ingots are heated at 460℃~470℃ for 41h~47h to complete the homogenization annealing treatment of the ingots. Then, milling, sawing, and skin welding are carried out. The hot finishing rolling temperature is 290℃~330℃. Then, it is cold rolled to Al-Zn-Mg-Cu aluminum alloy sheet with a finished thickness of 1.6mm~6.35mm.

5. The above-mentioned Al-Zn-Mg-Cu aluminum alloy sheet is subjected to finished product annealing. The first stage temperature is 399℃~409℃, held for 2h~3h, then cooled to 180℃~210℃, then heated to 227℃~237℃, held for 4h, cooled in the furnace for 1h~2h, and then removed from the furnace and air-cooled to obtain the finished annealed sheet. VI. The above-mentioned finished annealed sheet is subjected to roll straightening, finished shearing or sawing to obtain a high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet, thus completing the preparation method described above. The melting temperature in step two is 720℃~760℃; The amount of solvent #2 used in step two accounts for 0.1% to 0.3% of the total mass of the melt; The gas flow rate for the two-stage degassing process described in step three is 0.4 m³ / s. 3 / h~1.0m 3 / h, time is 30~50min; The Ar-Cl2 mixed gas mentioned in step three is a mixture of 95% high-purity argon and 5% high-purity chlorine. The amount of AlTi5B1 wire used in step three is 0.005 wt% of the melt with Ti element added. The speed at which the AlTi5B1 wire is inserted in step three is 520 mm / min; The leather welding process described in step four: 7072 alloy is used as the aluminum cladding material; the welding is done by riveting.

2. The method for preparing a high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet according to claim 1, characterized in that... In step one, the element weight percentages are as follows: Si≤0.50%, Fe≤0.30%, Cu:1.6%, Mn≤0.10%, Mg:2.5%, Zn:5.60%, Ti:0.03%, single impurity≤0.05%, total impurities≤0.15%, and the balance is Al.

3. The method for preparing a high-strength, damage-tolerant Al-Zn-Mg-Cu aluminum alloy O-state clad aluminum sheet according to claim 1, characterized in that... In step four, the alloy ingot is heated at 465℃ for 45 hours.

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