An additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with overall loading and local deformation

Abstract

A method for additive forging composite forming of an aluminum alloy lightweight wheel-shaped component with overall loading and local deformation relates to a method for additive forging composite forming of a wheel-shaped component. The present invention aims to solve the problems of poor organizational properties, difficulty in filling the forging forming mold, long forging process and high mold cost in the existing direct additive forming of aerospace aluminum alloy lightweight wheel-shaped components. Methods: 1. Additive forming of the main body billet; 2. Pre-forging forming of the spokes; 3. Machining and finishing of the pre-forgings; 4. Secondary additive forming of the rim; 5. Overall homogenization heat treatment of the wheel; 6. Overall forging forming of the wheel; 7. Direct aging strengthening treatment of the wheel. The present invention is used for additive forging composite forming of an aluminum alloy lightweight wheel-shaped component with overall loading and local deformation.

Description

Technical Field

[0001] The invention relates to an additive forging composite forming method for a wheel-shaped component. Background Art

[0002] As my country's exploration of deep space, including the moon and Mars, continues to deepen, higher requirements are being placed on new-generation spacecraft, such as manned lunar rovers and Mars rovers, for high performance, low weight, and diverse missions. Wheel components, as one of the main motion and load-bearing components, are developing towards high performance, individualized single-piece manufacturing, extreme lightweighting, and the integration of complex structural components. Therefore, the production and preparation process for lightweight wheel-shaped components in the aerospace field should feature rapid single-piece or small-batch manufacturing, short production cycles, and rapid upgrades, posing a significant challenge to processing and manufacturing technology. High-strength aluminum alloys, with their advantages of high specific strength, low density, good formability, and excellent corrosion resistance, are very suitable as materials for lightweight components and are currently widely used in the aerospace field.

[0003] The demand for extremely lightweight wheel-shaped components in the aerospace industry necessitates a high level of structural complexity. These lightweight wheel components consist of a thin-walled rim with a reinforced structure and spokes with complex topological hollow shapes. The topological spokes are the primary support component, responsible for supporting the entire wheel; the thin-walled rim is assembled to the outer tire, responsible for bearing the impact loads transmitted by the tire; and the spoke mounting flange is assembled to the axle and steering mechanism, responsible for transmitting driving force and steering torque. Therefore, these components place extremely high demands on their mechanical properties and require them to be formed as a single, integrated whole.

[0004] However, traditional processing technologies struggle to meet the manufacturing needs of new, lightweight, and complex wheel-shaped components in the aerospace sector. Forging blanks using die forging methods make it difficult to fully fill the wheel rim, requiring multiple sets of pre-forging dies. This results in complex blank making, high die costs, and a long manufacturing cycle. Emerging arc additive manufacturing technology can rapidly form complex components, offering advantages such as flexible materials, high manufacturing flexibility, fast forming speeds, and low single-piece or small-batch manufacturing costs. It is well-suited for processing large, complex, and integral components with high duty cycles, such as lightweight wheel-shaped components. However, arc additive components suffer from poor as-deposited microstructure and are sensitive to porosity defects, making them difficult to meet the high standards required for spacecraft.

[0005] Therefore, there is an urgent need for new forming methods to achieve rapid integral forming of lightweight wheel-shaped components made of aluminum alloys in the aerospace field while ensuring that the organizational properties of the spokes, rims, assembly areas, and transition areas of the wheel-shaped components are excellent and stable. Summary of the Invention

[0006] The present invention aims to solve the problems of poor microstructure and performance of existing aerospace aluminum alloy lightweight wheel-shaped components produced by direct additive forming, difficulty in filling forging forming dies, long forging process and high die costs, and further provide an additive forging composite forming method for overall loading and local deformation of aluminum alloy lightweight wheel-shaped components.

[0007] A method for additive forging composite forming of an aluminum alloy lightweight wheel-shaped component with overall loading and local deformation is provided, which is carried out in the following steps:

[0008] 1. Additive forming of main blank:

[0009] The wheel body is formed by using an arc wire feeding additive manufacturing method, and then the surface of the wheel body is polished and smoothed to obtain a wheel additive manufacturing blank;

[0010] The wheel additive blank is formed by connecting a rim and spokes;

[0011] 2. Spoke pre-forging and forming:

[0012] The wheel additive billet and the forging die are lubricated, and then the wheel additive billet is heated to the aluminum alloy forging temperature T1 and kept warm. Simultaneously, the forging die is preheated to the temperature T2. The wheel additive billet is then placed in the forging die and positioned. The spokes of the wheel additive billet are pre-forged at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, the wheel is cooled to room temperature in air, and flash is removed to obtain a wheel pre-forged part.

[0013] 3. Machining and finishing of pre-forged parts:

[0014] The upper and lower end surfaces of the wheel rim of the wheel preforging are processed to be flat, and the oxide layers on the inner and outer surfaces of the wheel rim are polished off to obtain a trimmed preforging;

[0015] 4. Secondary Additive Manufacturing of Wheel Rim:

[0016] Using the arc wire feeding additive manufacturing method, the upper and lower end faces of the rim and the inner and outer surfaces of the rim in the trimmed pre-forged part are subjected to secondary additive forming, and then polished to obtain a secondary additive wheel;

[0017] 5. Overall uniform heat treatment of wheels:

[0018] The secondary additively-reinforced wheel is subjected to a homogenizing heat treatment at a temperature of T3 for 8 to 24 hours, and finally cooled to room temperature in air to obtain a homogenized secondary additively-reinforced wheel;

[0019] 6. Wheel integral forging forming:

[0020] The homogenized secondary additive wheel and the forging die are lubricated, then the homogenized secondary additive wheel is heated to the aluminum alloy forging temperature T4 and kept warm. Meanwhile, the forging die is preheated to the temperature T5. The homogenized secondary additive wheel is then placed in the forging die and positioned. The homogenized secondary additive wheel is forged as a whole at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, the wheel is rapidly cooled to room temperature, and the flash is removed to obtain a final wheel forging.

[0021] 7. Direct aging strengthening treatment of wheels:

[0022] The wheel final forging is subjected to artificial aging strengthening treatment and then cooled to room temperature in air, thus completing the additive forging composite forming method of the aluminum alloy lightweight wheel-shaped component with overall loading and local deformation.

[0023] The beneficial effects of the present invention are:

[0024] The present invention provides an additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation. The method comprises preparing a wheel additive billet by an arc additive manufacturing method, pre-forging the wheel additive billet in a die to form spokes with a total required reduction of 40% to 60%, removing flash and performing surface finishing, then performing secondary additive processing on the rim of the pre-forged component to replenish material, performing overall homogenization treatment on the secondary additively processed wheel, and then performing overall forging in the same die to obtain a fully filled wheel final forging free of defects such as cracks and pores and having qualified shape and size, and finally performing artificial aging strengthening treatment to obtain a wheel component that meets the requirements in terms of final mechanical properties and shape and size.

[0025] The present invention uses an arc wire additive manufacturing method to prepare billets with complex structural shapes, replacing the traditional multiple-step billet making process. This shortens the manufacturing process and saves mold and forging billet costs, while also improving material utilization. By pre-forging the additive billet, followed by secondary additive filling of the rim portion, and then performing overall forging, the die cavity of the forging's higher rim portion is ensured to be completely filled, resolving the problem of insufficient filling of high-ribbed, deep-cavity areas with large aspect ratios in traditional one-step forging. Furthermore, this secondary additive filling method improves forging flexibility, and the same set of forging dies is used for both pre-forging and overall forging, significantly saving die manufacturing costs.

[0026] The present invention is formed by two forging processes, pre-forging and integral forging, wherein the metal volume of the spoke part of the additive blank is larger than the spoke part of the final forging, and its excess metal flows into the flash during the two forging processes, ensuring that the deformation of the spoke part is sufficient and preventing the thinner spoke part from becoming unstable during the forging process; the rim part of the additive blank produces a certain amount of deformation during the pre-forging process, and the integral forging after the secondary additive process further increases the overall deformation of the rim, ensuring that the deformation of the rim part is sufficient; the sufficient deformation of the arc additive blank allows the additive defects such as pores, cracks and unfused materials to be fully forged, reducing the brittleness of the additive component and improving the fatigue performance, while significantly improving the additive layered structure and reducing the anisotropy of the mechanical properties of the additive component, solving the problems of large residual stress, sensitive pore defects, and poor structure and mechanical properties of directly additive wheel components.

[0027] The present invention improves the uniformity of the microstructure and performance of the additive component by performing an overall homogenization heat treatment after the secondary additive process. This simultaneously narrows the microstructure and performance gap between the pre-forged component and the secondary additive component, improving the deformation coordination between the two components during the subsequent overall forging process. This effectively prevents forging filling difficulties and uneven microstructure and performance of the final forged component caused by uneven deformation. Furthermore, the additive-forging interface between the pre-forged component and the secondary additive component generates sufficient flow during the subsequent overall forging process, significantly eliminating defects such as poor fusion at the interface, improving the interface structure, and increasing the interface bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of one-step forging of a wheel-shaped component using the traditional process for comparative experiments. a is before forging, A is the upper die, B is the wheel forging blank, C is the lower die, b is after forging, and D is the unfilled part.

[0029] Figure 2 This is a schematic structural diagram of the wheel additive blank prepared in step 1 of Example 1;

[0030] Figure 3 Schematic diagram of the die cavity of the forging die used in step 2 and step 6 of Example 1, a is the upper die, b is the lower die, and c is a schematic diagram of the longitudinal section of the die cavity in the closed state of the die;

[0031] Figure 4 : These are the finite element simulation results of the spoke pre-forging process in step 2 of Example 1. a is a schematic diagram of a wheel pre-forging without removing the flash, and b is a local strain contour of the wheel pre-forging.

[0032] Figure 5 This is a schematic diagram of the trimmed pre-forged piece prepared in step 3 of Example 1;

[0033] Figure 6 Schematic diagram of a secondary additively manufactured wheel prepared in step 4 of Example 1, where A indicates the secondary additive locations on the upper and lower end surfaces of the rim;

[0034] Figure 7 : The finite element simulation results of the integral wheel forging process in step 6 of Example 1, a is the final wheel forging without removing the flash, and b is the local strain contour of the final wheel forging;

[0035] Figure 8 This is a schematic structural diagram of a wheel final forging prepared in step six of Example 1;

[0036] Figure 9 The figures are a comparison of the microstructures of the final forgings after aging prepared in Example 1 and Comparative Experiment 2, with a being Comparative Experiment 2 and b being Example 1;

[0037] Figure 10 Comparison of defects in the final forgings after aging prepared in Example 1 and Comparative Experiment 2, a is Comparative Experiment 2, b is Example 1;

[0038] Figure 11 The room temperature mechanical properties of the final forgings after aging prepared in Example 1 and Comparative Experiment 2 are compared. A is Comparative Experiment 2, and B is Example 1. DETAILED DESCRIPTION

[0039] Specific embodiment 1: This embodiment is an additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation, which is carried out in the following steps:

[0040] 1. Additive forming of main blank:

[0041] The wheel body is formed by using an arc wire feeding additive manufacturing method, and then the surface of the wheel body is polished and smoothed to obtain a wheel additive manufacturing blank;

[0042] The wheel additive blank is formed by connecting a rim and spokes;

[0043] 2. Spoke pre-forging and forming:

[0044] The wheel additive billet and the forging die are lubricated, and then the wheel additive billet is heated to the aluminum alloy forging temperature T1 and kept warm. Simultaneously, the forging die is preheated to the temperature T2. The wheel additive billet is then placed in the forging die and positioned. The spokes of the wheel additive billet are pre-forged at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, the wheel is cooled to room temperature in air, and flash is removed to obtain a wheel pre-forged part.

[0045] 3. Machining and finishing of pre-forged parts:

[0046] The upper and lower end surfaces of the wheel rim of the wheel preforging are processed to be flat, and the oxide layers on the inner and outer surfaces of the wheel rim are polished off to obtain a trimmed preforging;

[0047] 4. Secondary Additive Manufacturing of Wheel Rim:

[0048] Using the arc wire feeding additive manufacturing method, the upper and lower end faces of the rim and the inner and outer surfaces of the rim in the trimmed pre-forged part are subjected to secondary additive forming, and then polished to obtain a secondary additive wheel;

[0049] 5. Overall uniform heat treatment of wheels:

[0050] The secondary additively-reinforced wheel is subjected to a homogenizing heat treatment at a temperature of T3 for 8 to 24 hours, and finally cooled to room temperature in air to obtain a homogenized secondary additively-reinforced wheel;

[0051] 6. Wheel integral forging forming:

[0052] The homogenized secondary additive wheel and the forging die are lubricated, then the homogenized secondary additive wheel is heated to the aluminum alloy forging temperature T4 and kept warm. Meanwhile, the forging die is preheated to the temperature T5. The homogenized secondary additive wheel is then placed in the forging die and positioned. The homogenized secondary additive wheel is forged as a whole at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, the wheel is rapidly cooled to room temperature, and the flash is removed to obtain a final wheel forging.

[0053] 7. Direct aging strengthening treatment of wheels:

[0054] The wheel final forging is subjected to artificial aging strengthening treatment and then cooled to room temperature in air, thus completing the additive forging composite forming method of the aluminum alloy lightweight wheel-shaped component with overall loading and local deformation.

[0055] The beneficial effects of this embodiment are:

[0056] This embodiment provides an additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation, comprising preparing a wheel additive billet by an arc additive manufacturing method, pre-forging the wheel additive billet in a mold to form spokes with a total required reduction of 40% to 60%, removing flash and performing surface finishing, then performing secondary additive work on the rim of the pre-forged component to replenish material, and performing overall homogenization treatment on the secondary additively produced wheel, and then performing overall forging in the same mold to obtain a fully filled wheel final forging without defects such as cracks and pores, and with qualified shape and size, and finally performing artificial aging strengthening treatment to obtain a wheel component that meets the requirements in terms of final mechanical properties and shape and size.

[0057] This embodiment uses an arc wire additive manufacturing method to produce billets with complex structural shapes, replacing the traditional multi-step billet-making process. This shortens the manufacturing process and saves mold and forging costs, while also improving material utilization. By pre-forging the additive billet, then adding a secondary additive filling to the rim portion, and then performing the overall forging, the die cavity of the forging's higher rim area is completely filled, solving the problem of insufficient filling of high-ribbed, deep cavities with large aspect ratios in traditional one-step forging. This secondary additive filling method also improves forging flexibility, as the same set of forging dies is used for both pre-forging and overall forging, significantly saving die manufacturing costs.

[0058] This embodiment is formed by two forging processes, pre-forging and integral forging, wherein the metal volume of the spoke part of the additive billet is larger than the spoke part of the final forging, and its excess metal flows into the flash during the two forging processes, ensuring sufficient deformation of the spoke part and preventing the thinner spoke part from becoming unstable during the forging process; the rim part of the additive billet produces a certain amount of deformation during the pre-forging process, and the integral forging after the secondary additive process further increases the overall deformation of the rim, ensuring sufficient deformation of the rim part; the sufficient deformation of the arc additive billet allows the defects of additive pores, cracks and unfused parts to be fully forged, reducing the brittleness of the additive component and improving the fatigue performance, while significantly improving the additive layered structure and reducing the anisotropy of the mechanical properties of the additive component, solving the problems of large residual stress, sensitive pore defects, and poor structure and mechanical properties of directly additive wheel components.

[0059] This embodiment improves the uniformity of the additive component's microstructure and performance by performing an overall homogenization heat treatment after the secondary additive process. This simultaneously narrows the microstructure and performance gap between the pre-forged component and the secondary additive component, improving deformation coordination between the two components during the subsequent overall forging process. This effectively prevents forging filling difficulties and uneven microstructure and performance in the final forging caused by uneven deformation. Furthermore, the additive-forging interface between the pre-forged component and the secondary additive component generates sufficient flow during the subsequent overall forging process, significantly eliminating defects such as poor fusion at the interface, improving the interface structure, and increasing interfacial bonding strength.

[0060] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the raw materials used for arc wire additive manufacturing described in steps 1 and 4 are the same, namely 2xxx series aluminum alloy or 7xxx series aluminum alloy. Other aspects are the same as specific embodiment 1.

[0061] Specific embodiment three: This embodiment differs from either specific embodiment one or two in that: the spokes in the wheel augmentation blank described in step one are partially hollowed out; the size of a single hollow hole in the spokes in the wheel augmentation blank described in step one is 1.1 to 1.4 times the size of a single hollow hole in the spokes in the wheel final forging described in step six, and the aforementioned sizes are length and width; the thickness of the spokes in the wheel augmentation blank described in step one is 2 to 2.5 times the thickness of the spokes in the wheel final forging described in step six; the height of the rim in the wheel augmentation blank described in step one is 50% to 70% of the height of the rim in the wheel final forging described in step six; and the width of the rim in the wheel augmentation blank described in step one is 1.6 to 2 times the width of the rim in the wheel final forging described in step six. Other aspects are the same as specific embodiments one or two.

[0062] Specific embodiment 4: This embodiment differs from one of specific embodiments 1 to 3 in that the reduction during the pre-forging of the spokes in step 2 is 40% to 60% of the reduction required for complete closure of the forging die; and the spoke thickness in the pre-forging wheel in step 2 is 1 to 1.3 times the spoke thickness in the final forging wheel in step 6. This embodiment is the same as specific embodiments 1 to 3.

[0063] Specific Embodiment 5: This embodiment differs from one of Specific Embodiments 1 to 4 in that the rim height of the secondary augmented wheel in step 4 is 75% to 90% of the rim height of the wheel final forging in step 6; the rim width of the secondary augmented wheel in step 4 is 1.1 to 1.6 times the rim width of the wheel final forging in step 6, and both the inner and outer surfaces of the rim are parallel to the rim axis. Other aspects are the same as Specific Embodiments 1 to 4.

[0064] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the temperature T3 described in step 5 is the solution heat treatment temperature of the aluminum alloy. Other aspects are the same as specific embodiments 1 to 5.

[0065] The solution heat treatment temperature of the aluminum alloy described in this specific embodiment can be based on the standard solution heat treatment temperature of different aluminum alloys specified in the non-ferrous metal industry standard YS / T591-2017 Deformed Aluminum and Aluminum Alloy Heat Treatment, that is, the homogenization heat treatment temperature used in this specific embodiment is the same as the temperature in this standard.

[0066] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that in step 6, spraying or water quenching is used to quickly cool to room temperature. Other aspects are the same as specific embodiments 1 to 6.

[0067] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that: in step 2, T1=T2, and T1 is the aluminum alloy forging temperature; in step 6, T4=T5, and T4 is 85% to 95% of T1. Other aspects are the same as specific embodiments 1 to 7.

[0068] The aluminum alloy forging temperature described in this specific embodiment may be 70% to 80% of the aluminum alloy melting point.

[0069] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the forging die described in step 6 is the same as the forging die described in step 2. Other aspects are the same as specific embodiments 1 to 8.

[0070] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that the reduction amount during the integral forging process described in step 6 is the reduction amount required for the die to be completely closed. Other aspects are the same as specific embodiments 1 to 9.

[0071] The following examples are used to verify the beneficial effects of the present invention:

[0072] Example 1:

[0073] A method for additive forging composite forming of an aluminum alloy lightweight wheel-shaped component with overall loading and local deformation is provided, which is carried out in the following steps:

[0074] 1. Additive forming of main blank:

[0075] Using 2219 aluminum alloy welding wire as raw material, the wheel body is formed using the cold metal transfer arc wire feeding additive manufacturing method, and then the surface of the wheel body is polished and smoothed to obtain the wheel additive manufacturing blank;

[0076] The wheel additive billet is formed by connecting a rim and spokes, and the transition radius between the spokes and the rim is R5; the wheel additive billet has seven hollow holes evenly distributed along the circumference of the spokes, and a circular hole with a diameter of 120mm is set in the middle; a single hollow hole is 120mm long and 74mm wide, and the spoke thickness is 20mm; the wheel additive billet has an outer diameter of 560mm, a rim width of 50mm, and a rim height of 130mm;

[0077] 2. Spoke pre-forging and forming:

[0078] Graphite lubricant was sprayed on the surface of the wheel additive billet and the forging die. The wheel additive billet was then heated to 450°C and held at 450°C for 90 minutes. The forging die was also preheated to 450°C. The wheel additive billet was then placed in the forging die and positioned. The spokes of the wheel additive billet were pre-forged at a pressing speed of 2.5 mm / s. The billet was then cooled to room temperature in air and the flash was removed to obtain a wheel pre-forged part.

[0079] The forging die is an open die forging die;

[0080] The reduction amount during the spoke pre-forging process is 50% of the reduction amount required for the forging die to be completely closed;

[0081] The transition radius between the spoke and the rim in the wheel preforging is R20; the wheel spokes in the wheel preforging are evenly distributed along the circumference, with a circular hole with a diameter of 110 mm in the middle; a single hollow hole is 115 mm long and 64 mm wide, and a triangular indentation with a side length of 40 mm is provided between two adjacent hollow holes; the spoke thickness is 15 mm; the wheel rim in the wheel preforging has an outer diameter of 563 mm, a rim width of 30 mm, and a rim height of 150 mm;

[0082] 3. Machining and finishing of pre-forged parts:

[0083] The triangular indentation of the wheel preforging is removed by milling and angle grinding, and then the upper and lower end faces of the wheel rim of the wheel preforging are smoothed, and the oxide layer on the inner and outer surfaces of the wheel rim is ground off to obtain a trimmed preforging;

[0084] The transition radius between the spoke and the rim in the trimmed pre-forged part is R20; the spokes in the trimmed pre-forged part are evenly arranged along the circumference, with a circular hole with a diameter of 110 mm in the middle; a single hollow hole is 115 mm long and 64 mm wide, and a triangular hole with a side length of 40 mm is provided between two adjacent hollow holes; the spoke thickness is 15 mm; the rim outer diameter of the wheel pre-forged part is 563 mm, the rim width is 30 mm, and the rim height is 130 mm;

[0085] 4. Secondary Additive Manufacturing of Wheel Rim:

[0086] Using 2219 aluminum alloy welding wire as raw material, the cold metal transfer arc wire feeding additive manufacturing method is used to perform secondary additive forming on the upper and lower end faces of the rim and the inner and outer surfaces of the rim after trimming the pre-forged part, and then polished them flat to obtain the secondary additively manufactured wheel.

[0087] The transition radius between the spokes and the rim in the secondary additive wheel is R20; the spokes in the secondary additive wheel have 7 hollow holes evenly arranged along the circumference, and a circular hole with a diameter of 110 mm is set in the middle; a single hollow hole is 115 mm long and 64 mm wide, and a triangular hole with a side length of 40 mm is set between two adjacent hollow holes. The spoke thickness is 15 mm; the outer diameter of the rim in the secondary additive wheel is 563 mm, the rim width is 35 mm, and the rim height is 190 mm; and the inner and outer surfaces of the rim in the secondary additive wheel are parallel to the rim axis;

[0088] 5. Overall uniform heat treatment of wheels:

[0089] The secondary additively-reinforced wheel was subjected to homogenization heat treatment at a temperature of 510°C for 8 hours and finally cooled to room temperature in air to obtain a homogenized secondary additively-reinforced wheel.

[0090] 6. Wheel integral forging forming:

[0091] Graphite lubricant was sprayed on the surface of the homogenized secondary additive wheel and the forging die. The homogenized secondary additive wheel was then heated to 420°C and kept at 420°C for 90 minutes. The forging die was also preheated to 420°C. The homogenized secondary additive wheel was then placed in the forging die and positioned. The homogenized secondary additive wheel was forged as a whole at a pressing speed of 2.5 mm / s. Finally, the wheel was rapidly cooled to room temperature by water quenching and the flash was removed to obtain the final wheel forging.

[0092] The forging die described in step 6 is the same as the forging die described in step 2; the pressing amount during the integral forging process is the pressing amount required for the die to be completely closed;

[0093] The transition radius between the spokes and the rim in the wheel final forging is R20; the spokes in the wheel final forging are evenly distributed along the circumference, with a circular hole with a diameter of 110 mm in the middle; a single hollow hole is 110 mm long and 54 mm wide, and a triangular hole with a side length of 40 mm is provided between two adjacent hollow holes; the spoke thickness is 10 mm; the rim outer diameter of the wheel final forging is 563 mm, the rim width is 22 mm, and the rim height is 220 mm;

[0094] 7. Direct aging strengthening treatment of wheels:

[0095] The wheel final forging was subjected to artificial aging treatment at a temperature of 165°C for 16 hours and then cooled to room temperature in air to obtain the aged final forging.

[0096] In step 4 of this embodiment, the maximum outer diameter of the wheel rim does not change. Since the outer rim has an inclination, the outer inclination is filled after the outer side is increased, so the outer rim becomes a straight wall.

[0097] Comparative experiment 1:

[0098] A 2219 aluminum alloy forging blank is used and machined to obtain a wheel forging blank. The forging blank and the die are heated to 450°C and kept warm. Then, the forging blank is placed in the die and forged at a pressing speed of 2.5 mm / s. After forging, the blank is cooled to room temperature in air, and then subjected to a solution treatment at 535°C / 2h and an aging treatment at 120°C / 24h to obtain a wheel forging formed in one step.

[0099] Comparative Experiment 2: Using 2219 aluminum alloy welding wire as the raw material, the wheel final forging described in Step 6 of Example 1 was directly formed in one step using a cold metal transfer arc wire feeding additive manufacturing method. The wheel final forging was then artificially aged at 165°C for 16 hours and then cooled to room temperature in air to obtain the aged final forging.

[0100] Figure 1 For comparative experiments, a schematic diagram of the one-time forging forming process of a wheel-shaped component using the traditional process is shown. a is before forging, A is the upper die, B is the wheel forging blank, C is the lower die, b is after forging, and D is the unfilled part. As can be seen from the figure, due to the large height-to-thickness ratio of the final forging (the height-to-thickness ratio is 5:1), it is difficult to completely fill the edge of the wheel rim in one forging.

[0101] Figure 2 This is a schematic structural diagram of the wheel additive blank prepared in step 1 of Example 1;

[0102] Figure 3 Schematic diagram of the die cavity of the forging die used in step 2 and step 6 of Example 1, a is the upper die, b is the lower die, and c is a schematic diagram of the longitudinal section of the die cavity in the closed state of the die;

[0103] Figure 4 These are the finite element simulation results of the spoke pre-forging process in step 2 of Example 1. a is a schematic diagram of the wheel pre-forging without removing the flash, and b is a local strain cloud diagram of the wheel pre-forging. It can be seen from the figure that after pre-forging, the strain of the spoke part is above 0.5, the rim part also produces a certain amount of deformation, and there is no folding defect at the transition radius between the spoke and the rim.

[0104] Figure 5 This is a schematic diagram of the trimmed pre-forged piece prepared in step 3 of Example 1;

[0105] Figure 6 Schematic diagram of a secondary additively manufactured wheel prepared in step 4 of Example 1, where A indicates the secondary additive locations on the upper and lower end surfaces of the rim;

[0106] Figure 7 This is the finite element simulation result of the integral forging process of the wheel in step six of Example 1, where a is the final wheel forging without removing the flash, and b is the local strain cloud diagram of the final wheel forging. It can be seen from the figure that the strain of the final forging reaches above 0.5 in the entire region, and the strain of key load-bearing parts such as the transition between the spoke and rim and the outer edge of the rim can reach above 1. The overall deformation is sufficient to ensure that the defects of the additive are completely forged and the additive structure is fully improved. In addition, the difficult-to-fill parts on the edge of the rim are completely filled, the final forging is fully formed, without defects such as cracks and pores, and the shape and size are qualified.

[0107] Figure 8 This is a schematic diagram of the wheel final forging structure prepared in step six of Example 1; as can be seen from the figure, the forging formed by this method has high form-conformity, small machining allowance, high material utilization rate, cost savings, and shape and size that meet the requirements.

[0108] Figure 9 The figures are a comparison of the microstructures of the final forgings after aging prepared in Example 1 and Comparative Experiment 2, where a is Comparative Experiment 2 and b is Example 1. As can be seen from the figure, the microstructure of the direct additively formed microstructure in Comparative Experiment 2 has uneven grain size and an obvious layered structure. The microstructure formed by the method of Example 1 has fine and uniform grains and no layered structure, proving that this method can significantly improve the additive microstructure.

[0109] Figure 10 The defects of the final forgings after aging prepared in Example 1 and Comparative Experiment 2 are compared, a is Comparative Experiment 2, and b is Example 1; in Comparative Experiment 2, direct additive forming was performed, and a large number of pores (A) and unfused (B) defects were present inside the alloy; in Example 1, the forming method had no defects such as pores inside, and the structure was dense, proving that this method can effectively eliminate additive defects.

[0110] Samples were taken from the spokes of the final forging after aging and the tensile rate was 0.001s -1 Mechanical properties test was carried out under the conditions of Figure 11 The room temperature mechanical properties of the final forgings after aging prepared in Example 1 and Comparative Experiment 2 are compared, with A being Comparative Experiment 2 and B being Example 1. As can be seen from the figure, the room temperature tensile curve of the direct additively formed component in Comparative Experiment 2 shows a tensile strength of only 265 MPa and a low elongation. The room temperature tensile curve of the component formed by the method of Example 1 shows a tensile strength of 385 MPa, an increase of 31.1%, and a significant increase in elongation, demonstrating that its strength and toughness are higher than those of direct additively formed components.

Claims

1. A method for additive forging composite forming of a lightweight aluminum alloy wheel-shaped component with overall loading and local deformation, characterized in that It is carried out in the following steps:

1. Additive forming of main blank: The wheel body is formed by using an arc wire feeding additive manufacturing method, and then the surface of the wheel body is polished and smoothed to obtain a wheel additive manufacturing blank; The wheel additive blank is formed by connecting a rim and spokes; 2. Spoke pre-forging and forming: The wheel additive billet and the forging die are lubricated, and then the wheel additive billet is heated to the aluminum alloy forging temperature T1 and kept warm. Simultaneously, the forging die is preheated to the temperature T2. The wheel additive billet is then placed in the forging die and positioned. The spokes of the wheel additive billet are pre-forged at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, the wheel is cooled to room temperature in air, and flash is removed to obtain a wheel pre-forged part.

3. Machining and finishing of pre-forged parts: The upper and lower end surfaces of the wheel rim of the wheel preforging are processed to be flat, and the oxide layers on the inner and outer surfaces of the wheel rim are polished off to obtain a trimmed preforging; 4. Secondary Additive Manufacturing of Wheel Rim: Using the arc wire feeding additive manufacturing method, the upper and lower end faces of the rim and the inner and outer surfaces of the rim in the trimmed pre-forged part are subjected to secondary additive forming, and then polished to obtain a secondary additive wheel; 5. Overall uniform heat treatment of wheels: The secondary additively-reinforced wheel is subjected to a homogenizing heat treatment at a temperature of T3 for 8 to 24 hours, and finally cooled to room temperature in air to obtain a homogenized secondary additively-reinforced wheel; 6. Overall forging of wheels: The homogenized secondary additive wheel and the forging die are lubricated, then the homogenized secondary additive wheel is heated to the aluminum alloy forging temperature T4 and kept warm. Meanwhile, the forging die is preheated to the temperature T5. The homogenized secondary additive wheel is then placed in the forging die and positioned. The homogenized secondary additive wheel is forged as a whole at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, the wheel is rapidly cooled to room temperature, and the flash is removed to obtain a final wheel forging.

7. Direct aging strengthening treatment of wheels: The wheel final forging is subjected to artificial aging strengthening treatment and then cooled to room temperature in air, thus completing the additive forging composite forming method of the aluminum alloy lightweight wheel-shaped component with overall loading and local deformation.

2. The additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation according to claim 1 is characterized in that The raw materials used in the arc wire additive manufacturing described in step 1 and step 4 are the same, namely 2xxx series aluminum alloy or 7xxx series aluminum alloy.

3. The additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation according to claim 1 is characterized in that The spokes in the wheel augmented material blank described in step one are partially hollowed out structures; the size of a single hollow hole of the spokes in the wheel augmented material blank described in step one is 1.1 to 1.4 times the size of a single hollow hole of the spokes in the wheel final forging described in step six, and the sizes are length and width; the thickness of the spokes in the wheel augmented material blank described in step one is 2 to 2.5 times the thickness of the spokes in the wheel final forging described in step six; the height of the rim in the wheel augmented material blank described in step one is 50% to 70% of the height of the rim in the wheel final forging described in step six; the width of the rim in the wheel augmented material blank described in step one is 1.6 to 2 times the width of the rim in the wheel final forging described in step six.

4. The additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation according to claim 1 is characterized in that The reduction amount during the pre-forging process of the spokes in step 2 is 40% to 60% of the reduction amount required for the forging die to be completely closed; the thickness of the spokes in the pre-forging wheel in step 2 is 1 to 1.3 times the thickness of the spokes in the final forging wheel in step 6.

5. The additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation according to claim 1 is characterized in that The rim height of the secondary additively manufactured wheel in step 4 is 75% to 90% of the rim height of the wheel final forging in step 6; the rim width of the secondary additively manufactured wheel in step 4 is 1.1 to 1.6 times the rim width of the wheel final forging in step 6, and the inner and outer surfaces of the rim in the secondary additively manufactured wheel are parallel to the rim axis.

6. The additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation according to claim 1 is characterized in that The temperature T3 described in step five is the solution heat treatment temperature of the aluminum alloy.

7. The additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation according to claim 1 is characterized in that In step six, the material is rapidly cooled to room temperature by spraying or water quenching.

8. The additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation according to claim 1 is characterized in that In step 2, T1=T2, and T1 is the forging temperature of the aluminum alloy; in step 6, T4=T5, and T4 is 85% to 95% of T1.

9. The additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation according to claim 1 is characterized in that The forging die described in step six is ​​the same as the forging die described in step two.

10. The additive forging composite forming method for an aluminum alloy lightweight wheel-shaped component with integral loading and local deformation according to claim 1, characterized in that The amount of reduction during the integral forging process described in step six is ​​the amount of reduction required for the die to be completely closed.

Images