Preparation method of Al-Cu-Mg aluminum alloy thin-wall small-specification extruded profile for aviation

Abstract

The invention discloses a preparation method of an Al-Cu-Mg aluminum alloy thin-wall small-specification extruded profile for aviation, and relates to a preparation method of an Al-Cu-Mg aluminum alloy thin-wall small-specification extruded profile. In order to solve the technical problems of extrusion forming, solution treatment and the like of the Al-Cu-Mg aluminum alloy thin-wall small-specification profile, the method comprises the following steps: homogenizing annealing of a cast ingot, turning of the cast ingot, heating of the cast ingot, extrusion of the cast ingot, two-stage solution treatment, stretching of the profile and natural aging. According to the Al-Cu-Mg aluminum alloy thin-wall small-specification extruded profile for aviation, the tensile strength of a T3511-state profile can reach 436 MPa-512 MPa, the yield strength can reach 329 MPa-403 MPa, the percentage elongation after fracture is larger than 13.64%-20.53%, all properties meet the product standard requirements, and the localization autonomous guarantee capacity of aluminum alloy raw materials for aviation is improved. The method is applied to the technical field of aluminum alloy extrusion material processing.

Description

Technical Field

[0001] The invention belongs to a method for preparing an Al-Cu-Mg aluminum alloy thin-wall small-size extruded profile for aviation. Background Art

[0002] With the rapid development of the aviation industry and the proposal of the dual carbon strategy of "carbon peak" and "carbon neutrality", the aviation industry has higher requirements for reducing energy consumption and lightweighting, and at the same time, it has also put forward more stringent requirements for the aluminum alloy manufacturing industry. Aviation aluminum is also developing towards higher strength and better comprehensive performance. Al-Cu-Mg aluminum alloy extruded profiles have been widely used due to their high strength, significant heat treatment strengthening effect and other excellent comprehensive properties. Domestically, some research has been carried out on small-size profiles for domestic large-scale fire-fighting / water rescue amphibious aircraft. In order to meet the urgent needs of localization of key aluminum alloy materials for this type of aircraft, through industrial preparation technology research, the technical problems of Al-Cu-Mg aluminum alloy thin-walled small-size profile extrusion molding, solid solution process and other technical problems are solved, and the independent guarantee capability of localization of aviation aluminum alloy raw materials is enhanced. Summary of the invention

[0003] The invention aims to provide a method for preparing a thin-walled small-size extruded Al-Cu-Mg aluminum alloy profile for aviation.

[0004] The preparation method of the Al-Cu-Mg aluminum alloy thin-wall small-size extruded profile for aviation of the present invention is carried out by the following steps:

[0005] 1. heating the Al-Cu-Mg aluminum alloy ingot to 480°C to 490°C, keeping the temperature for 6h to 15h, taking the ingot out of the furnace and air cooling it after the end of the heat preservation, and obtaining the Al-Cu-Mg aluminum alloy ingot after homogenization treatment;

[0006] 2. The Al-Cu-Mg aluminum alloy ingot obtained in step 1 after homogenization treatment is subjected to lathing to obtain an extruded ingot blank;

[0007] 3. The Al-Cu-Mg aluminum alloy ingot obtained in step 2 is heated to 410° C. to 430° C. for 5 h to 10 h, and extruded by an extrusion die after being taken out of the furnace;

[0008] 4. The Al-Cu-Mg aluminum alloy extruded profile obtained in step 3 is subjected to solution heat treatment, kept at a temperature of 480°C to 486°C for 15min to 35min, then heated to 490°C to 496°C for 35min to 55min, and stretched within 4h, with the stretching amount controlled at 1.5% to 3.0%, to obtain an Al-Cu-Mg aluminum alloy quenched and stretched profile;

[0009] 5. The Al-Cu-Mg aluminum alloy quenched and stretched profile obtained in step 4 is naturally aged to obtain an Al-Cu-Mg aluminum alloy T3511 profile.

[0010] Beneficial effects of the present invention:

[0011] 1. The present invention develops a method for preparing thin-walled small-size extruded profiles of Al-Cu-Mg aluminum alloy for aviation, designs a special extrusion die for profile extrusion, solves the problems of difficult control of wall thickness and external dimensions of small-wall profiles, and ensures that the final product meets the standard requirements.

[0012] 2. The present invention develops a method for preparing thin-walled small-size extruded profiles of Al-Cu-Mg aluminum alloy for aviation. A two-stage solid solution method is adopted. During the solid solution, the first stage solid solution treatment is carried out at a relatively low temperature to release more deformation energy storage, reduce the recrystallization driving force of the high-temperature solid solution treatment, and improve the alloy performance. Then, a high-temperature second stage solid solution treatment is carried out to improve the dissolution effect of the second phase. The average tensile strength in the T3511 state can reach 468MPa, which is 92MPa higher than the product standard requirement, and the average yield strength can reach 356MPa, which is 66MPa higher than the product standard requirement. It solves the demand for high-strength aluminum alloy materials for key aircraft models and meets the airworthiness certification requirements for key aircraft models. It can be widely used in my country's aerospace field to replace imports and realize the urgent purpose of domestic independent guarantee.

[0013] The invention is suitable for preparing Al-Cu-Mg aluminum alloy thin-wall small-size extruded profiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the cross-section diagram of the profile;

[0015] Figure 2 It is a special mold for profiles used in the embodiment;

[0016] Figure 3 The profile is extruded by a special die in the embodiment;

[0017] Figure 4 The metallographic structures at the head and tail positions of the Al-Cu-Mg aluminum alloy thin-walled small-size extruded profile for aviation prepared in the example. DETAILED DESCRIPTION

[0018] Specific implementation method 1: In this implementation method, a method for preparing a thin-walled small-size Al-Cu-Mg aluminum alloy extruded profile for aviation is carried out according to the following steps:

[0019] 1. heating the Al-Cu-Mg aluminum alloy ingot to 480°C to 490°C, keeping the temperature for 6h to 15h, taking the ingot out of the furnace and air cooling it after the end of the heat preservation, and obtaining the Al-Cu-Mg aluminum alloy ingot after homogenization treatment;

[0020] 2. The Al-Cu-Mg aluminum alloy ingot obtained in step 1 after homogenization treatment is subjected to lathing to obtain an extruded ingot blank;

[0021] 3. The Al-Cu-Mg aluminum alloy ingot obtained in step 2 is heated to 410° C. to 430° C. for 5 h to 10 h, and extruded by an extrusion die after being taken out of the furnace;

[0022] 4. The Al-Cu-Mg aluminum alloy extruded profile obtained in step 3 is subjected to solution heat treatment, kept at a temperature of 480°C to 486°C for 15min to 35min, then heated to 490°C to 496°C for 35min to 55min, and stretched within 4h, with the stretching amount controlled at 1.5% to 3.0%, to obtain an Al-Cu-Mg aluminum alloy quenched and stretched profile;

[0023] 5. The Al-Cu-Mg aluminum alloy quenched and stretched profile obtained in step 4 is naturally aged to obtain an Al-Cu-Mg aluminum alloy T3511 profile.

[0024] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that: Step 1 is heating to 485° C. and keeping the temperature for 8 hours. The rest is the same as the specific implementation method 1.

[0025] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that: in step 3, the temperature is heated to 420° C. to 430° C. for 6 hours. The rest is the same as specific implementation method 1 or 2.

[0026] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the extrusion die described in step 3 is an alloy cylinder with a T-shaped through hole. The rest is the same as specific embodiments 1 to 3.

[0027] Specific implementation method 5: This implementation method is different from specific implementation methods 1 to 4 in that the extrusion is performed in step 3 in a forward extrusion manner. The rest is the same as specific implementation methods 1 to 4.

[0028] Specific embodiment 6: This embodiment is different from specific embodiments 1 to 5 in that: in step 4, the temperature is kept at 483°C for 20 minutes, and then the temperature is raised to 496°C and kept for 51 minutes. The rest is the same as specific embodiments 1 to 5.

[0029] Specific implementation method 7: This implementation method is different from specific implementation methods 1 to 6 in that: Step 4 is stretched within 4 hours, and the stretching amount is controlled at 2.0% to 2.5%. The rest is the same as specific implementation methods 1 to 6.

[0030] Specific implementation example 8: This implementation example is different from specific implementation examples 1 to 7 in that the natural aging in step 5 refers to natural parking for 96 hours. The rest is the same as specific implementation examples 1 to 7.

[0031] 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.

[0032] Embodiment 1: The preparation method of a thin-walled small-size Al-Cu-Mg aluminum alloy extruded profile for aviation use in this embodiment is carried out according to the following steps:

[0033] 1. heating the Al-Cu-Mg aluminum alloy ingot to 485°C, keeping the temperature for 8 hours, taking the ingot out of the furnace and air cooling it after the end of the heat preservation, and obtaining the Al-Cu-Mg aluminum alloy ingot after homogenization treatment;

[0034] 2. The Al-Cu-Mg aluminum alloy ingot obtained in step 1 after homogenization treatment is subjected to lathing to obtain an extruded ingot blank with a specification of φ80 mm×240 mm;

[0035] 3. Heat the Al-Cu-Mg aluminum alloy ingot obtained in step 2 to 420°C-430°C for 6 hours, and then use a self-designed extrusion die (such as Figure 2 As shown), extrusion is performed by forward extrusion;

[0036] 4. The Al-Cu-Mg aluminum alloy extruded profile obtained in step 3 is subjected to solution heat treatment, kept at 483°C for 20 minutes, then heated to 496°C for 51 minutes, and stretched within 4 hours, with the stretching amount controlled at 2.0% to 2.5%, to obtain an Al-Cu-Mg aluminum alloy quenched and stretched profile;

[0037] 5. The Al-Cu-Mg aluminum alloy quenched and stretched profile obtained in step 4 is naturally aged and naturally parked for more than 96 hours to obtain an Al-Cu-Mg aluminum alloy T3511 state profile.

[0038] The Al-Cu-Mg aluminum alloy thin-walled small-size extruded profile for aviation obtained in this embodiment (profile cross-section diagram as shown in FIG. Figure 1 As shown, the actual profile is as Figure 3 shown), Figure 4 is the metallographic structure of the head and tail of the extruded profile. Figure 4It can be seen that there are only a small amount of S phase and Fe phase in the metallographic structure, the overall solid solution effect is good, and the head and tail structures are relatively uniform. The tensile strength of thin-walled small-size extruded profiles of Al-Cu-Mg aluminum alloy for aviation can reach 436MPa~512MPa, the yield strength can reach 329MPa~403MPa, and the elongation after fracture is greater than 13.64%~20.53%.

Claims

1. A method for preparing thin-walled small-size extruded Al-Cu-Mg aluminum alloy profiles for aviation, characterized in that The method proceeds as follows:

1. heating the Al-Cu-Mg aluminum alloy ingot to 480°C to 490°C, keeping the temperature for 6h to 15h, taking the ingot out of the furnace and air cooling it after the end of the heat preservation, and obtaining the Al-Cu-Mg aluminum alloy ingot after homogenization treatment; 2. The Al-Cu-Mg aluminum alloy ingot obtained in step 1 after homogenization treatment is subjected to lathing to obtain an extruded ingot blank; 3. The Al-Cu-Mg aluminum alloy ingot obtained in step 2 is heated to 410° C. to 430° C. for 5 h to 10 h, and extruded by an extrusion die after being taken out of the furnace; 4. The Al-Cu-Mg aluminum alloy extruded profile obtained in step 3 is subjected to solution heat treatment, kept at a temperature of 480°C to 486°C for 15min to 35min, then heated to 490°C to 496°C for 35min to 55min, and stretched within 4h, with the stretching amount controlled at 1.5% to 3.0%, to obtain an Al-Cu-Mg aluminum alloy quenched and stretched profile; 5. The Al-Cu-Mg aluminum alloy quenched and stretched profile obtained in step 4 is naturally aged to obtain an Al-Cu-Mg aluminum alloy T3511 profile.

2. The method for preparing a thin-walled small-size Al-Cu-Mg aluminum alloy extruded profile for aviation according to claim 1, characterized in that: Step 1: Heat to 485°C and keep warm for 8 hours.

3. The method for preparing a thin-walled small-size Al-Cu-Mg aluminum alloy extruded profile for aviation according to claim 1, characterized in that: In step 3, the temperature is heated to 420°C to 430°C for 6 hours.

4. The method for preparing a thin-walled small-size Al-Cu-Mg aluminum alloy extruded profile for aviation according to claim 1, characterized in that: The extrusion die described in step 3 is an alloy cylinder with a T-shaped through hole.

5. The method for preparing a thin-walled small-size Al-Cu-Mg aluminum alloy extruded profile for aviation according to claim 1, characterized in that: In step three, the extrusion is performed by forward extrusion.

6. The method for preparing a thin-walled small-size Al-Cu-Mg aluminum alloy extruded profile for aviation use according to claim 1, characterized in that: In step 4, the temperature is kept at 483° C. for 20 minutes, and then the temperature is increased to 496° C. and kept for 51 minutes.

7. The method for preparing a thin-walled small-size Al-Cu-Mg aluminum alloy extruded profile for aviation according to claim 1, characterized in that: Step 4: Stretching is performed within 4 hours, and the stretching amount is controlled at 2.0% to 2.5%.

8. The method for preparing a thin-walled small-size Al-Cu-Mg aluminum alloy extruded profile for aviation use according to claim 1, characterized in that: The natural aging in step five refers to natural parking for 96 hours.

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