Low-energy-consumption efficient forging method for truck swing arm

Abstract

The invention relates to the technical field of swing arm forging, and discloses a truck swing arm low-energy-consumption efficient forging method which comprises the steps that S1, material selection and preparation are conducted, specifically, an aluminum alloy bar meeting the use requirement is selected, and weighing and preparation are conducted; s2, heating and cleaning are conducted, specifically, double-length bar billets are adopted for feeding, the bar billets are heated to 1150-1320 DEG C, and oxide skin on the surfaces of the bar billets is cleaned; s3, forging forming is conducted, specifically, a free forging process is selected, the heated blank is machined into a dumbbell blank, and heat preservation is conducted; s4, surface treatment is conducted, specifically, oxide skin on the surface of the forged and formed rough blank is cleaned, and cutting and annealing heat treatment are conducted; and S5, casting and forming are conducted, specifically, the treated blank is melted, poured into a casting mold, taken out after being cooled and subjected to shot blasting surface treatment. The tensile strength, the yield strength and the ductility of the swing arm are obviously higher than those of traditional steel, the swing arm can bear high load and complex stress conditions, the service life is prolonged, and the safety is improved.

Description

Technical Field

[0001] The invention relates to the technical field of swing arm forging, in particular to a low-energy-consumption and high-efficiency forging method for a truck swing arm. Background Art

[0002] With the rapid development of the modern automobile industry, new requirements are constantly being raised for the performance and manufacturing process of automobile parts. As an important part of the automobile suspension system, the swing arm plays a vital role in bearing and transmitting various forces and movements between the wheels and the body. Traditional automobile swing arms are mostly made of carbon steel and are formed by forging and processing.

[0003] However, the tensile strength and yield strength of traditional carbon steel materials are relatively low. Although its elongation is high, the swing arm is prone to deformation and breakage under high load and complex stress conditions, affecting the stability and safety of the vehicle. For this reason, the present invention proposes a low-energy and high-efficiency forging method for a truck swing arm. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a low-energy consumption and high-efficiency forging method for a truck swing arm, which solves the problem that the traditional truck swing arm is prone to deformation and fracture under high load and complex stress conditions.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A low-energy-consumption and high-efficiency forging method for a truck swing arm, comprising the following steps:

[0006] S1. Material selection and preparation: Select aluminum alloy bars that meet the use requirements and weigh and prepare the materials;

[0007] S2. Heating and cleaning: Use double-sized billets for feeding, heat the billets to 1150-1320°C, and clean the oxide scale on the surface of the billets;

[0008] S3, forging: select the free forging process, process the heated billet into a dumbbell billet, and keep it warm;

[0009] S4, surface treatment: clean the oxide scale on the surface of the rough billet after forging, and perform cutting and annealing heat treatment;

[0010] S5, casting and molding: melt the treated blank, pour it into a casting mold, take it out after cooling, and perform shot blasting surface treatment;

[0011] S6. Heat treatment: heat the cast swing arm to 510-535°C, perform quenching treatment, and control the cooling rate to be below 50°C / s;

[0012] S7. Assembly: Install the accessories of the swing arm after heat treatment, including the ball pin, the first bushing, the second bushing and the hydraulic bushing.

[0013] Preferably, the composition and mass percentage of the aluminum alloy bar described in step S1 are: Si: 0.58-0.63%, Fe: 0.35%, Cu: 0.19-0.24%, Mn: 0.1%, Mg: 0.9-0.95%, Cr: 0.08-0.13%, Zn: 0.1%, Ti: 0.1%, and the remainder is Ai.

[0014] Preferably, the heating in step S2 adopts a two-stage heating method, including:

[0015] S2.1. Keep the temperature at 800℃ to eliminate the stress inside the material and ensure uniform heating;

[0016] S2.2. Rapidly heat to 1150-1320℃ and maintain for 0.8-2h to reach the temperature required for forging and improve the plasticity of the material.

[0017] Preferably, the cleaning in step S2 includes:

[0018] S2.3. Use an air compressor to blow and clean the surface of the high-temperature billet to remove the oxide scale and improve the surface quality;

[0019] S2.4. Clean the oxide scale on the surface of the bar to prevent the oxide scale from damaging the mold and forgings in subsequent processes.

[0020] Preferably, the forging forming in step S3 includes:

[0021] S3.1. Select the free forging process to preliminarily forge the heated billet into a dumbbell billet close to the target shape;

[0022] S3.2. Keep the temperature of the dumbbell blank stable to avoid hardening and deformation caused by material cooling and ensure forging quality.

[0023] Preferably, the surface treatment in step S4 includes:

[0024] S4.1. Use air compressor to clean the surface of high-temperature billet and the inside of pre-forging die to prevent oxide scale from accelerating die wear;

[0025] S4.2. Cut the forgings and perform annealing heat treatment to make the material structure more uniform and improve its subsequent processing performance.

[0026] Preferably, the casting and molding in step S5 includes:

[0027] S5.1. Heat the treated blank to 565-675°C to make the aluminum alloy molten for easy casting;

[0028] S5.2. Pour the molten aluminum alloy into a casting mold for cooling, and produce multiple products at one time through the mold to reduce manufacturing costs.

[0029] Preferably, the surface treatment in step S5 includes:

[0030] S5.3. Use a shot blasting machine to perform surface treatment to remove excess aluminum alloy around the swing arm during the casting process to ensure surface smoothness;

[0031] S5.4. Remove excess aluminum alloy during the casting process to obtain a separate aluminum alloy swing arm, which is convenient for subsequent processing and material recycling.

[0032] Preferably, the heat treatment in step S6 includes:

[0033] S6.1. Heat the cast swing arm to 510-535℃ and perform quenching treatment to ensure uniform internal structure of the material;

[0034] S6.2. Control the cooling rate below 50℃ / s to improve the internal structural strength of the aluminum alloy and avoid cracks during the cooling process.

[0035] The present invention provides a low-energy-consumption and high-efficiency forging method for a truck swing arm. It has the following beneficial effects:

[0036] 1. The tensile strength, yield strength and elongation of the swing arm of the present invention are significantly higher than those of traditional steel. The tensile strength is up to 500MPa, the yield strength is up to 330MPa, and the elongation is maintained between 17% and 19%, which are all better than traditional steel. The swing arm of the present invention can better withstand high loads and complex stress conditions, and improves service life and safety.

[0037] 2. The energy consumption of the swing arm forging method of the present invention is significantly lower than that of traditional steel. The energy consumption of traditional steel is 120kWh, while the energy consumption of the embodiment can reach 88kWh at the lowest and 92kWh at the highest. This makes the present invention more energy-saving and environmentally friendly during the production process, and can effectively reduce manufacturing costs and carbon emissions.

[0038] 3. The components of the swing arm casting aluminum alloy of the present invention include Si, Fe, Cu, Mn, Mg, Cr, Zn, Ti and other elements, and have excellent mechanical properties and machinability. These alloy elements form fine precipitates during the forging process, hindering the movement of the grain boundaries and improving the strength and hardness of the alloy. In addition, the aluminum alloy material is lighter than traditional carbon steel, which reduces the burden on the wheels and improves fuel efficiency. DETAILED DESCRIPTION

[0039] The following will be combined with the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Embodiment 1:

[0041] The embodiment of the present invention provides a basic embodiment of a low-energy-consumption and high-efficiency forging method for a truck swing arm, comprising:

[0042] Material selection and preparation:

[0043] 6061 aluminum alloy bar was selected, and the composition and mass percentage were: Si: 0.60%, Fe: 0.35%, Cu: 0.20%, Mn: 0.10%, Mg: 0.92%, Cr: 0.10%, Zn: 0.10%, Ti: 0.10%, and the balance was aluminum.

[0044] Weigh and prepare ingredients.

[0045] Heating and cleaning:

[0046] The double-length bar blank was heated to 800°C and kept warm, and then rapidly heated to 1150°C and kept for 1.5 hours.

[0047] Use an air compressor to blow air to clean the surface of the high-temperature billet to remove the oxide scale.

[0048] Forging forming:

[0049] Select the free forging process to preliminarily forge the heated billet into a dumbbell billet and keep the temperature stable.

[0050] Surface treatment:

[0051] Use an air compressor to blow air to clean the surface of the high-temperature billet and the inside of the pre-forging die, and to clean the oxide scale on the surface of the rough billet after forging.

[0052] The forgings are cut and annealed to make the material structure more uniform.

[0053] Casting and molding:

[0054] The processed blank is heated to 600°C, melted and poured into a casting mold for cooling.

[0055] Use a shot blasting machine for surface treatment to remove excess aluminum alloy around the swing arm during the casting process.

[0056] Heat Treatment:

[0057] The cast swing arm is heated to 520°C and quenched, and the cooling rate is controlled below 50°C / s.

[0058] Assembly:

[0059] Fix the ball pin vertically on the surface of the ball seat and install the protective cover.

[0060] Press rings are embedded in the ports of the first bushing, the second bushing and the hydraulic bushing.

[0061] Embodiment 2:

[0062] The embodiment of the present invention provides a high temperature and high pressure embodiment of a low energy consumption and high efficiency forging method for a truck swing arm, comprising:

[0063] Material selection and preparation:

[0064] 6061 aluminum alloy bar was selected, and the composition and mass percentage were: Si: 0.62%, Fe: 0.34%, Cu: 0.22%, Mn: 0.11%, Mg: 0.93%, Cr: 0.11%, Zn: 0.09%, Ti: 0.11%, and the balance was aluminum.

[0065] Weigh and prepare ingredients.

[0066] Heating and cleaning:

[0067] The double-length bar blank was heated to 800°C and kept warm, and then rapidly heated to 1200°C and kept for 1 hour.

[0068] Use an air compressor to blow air to clean the surface of the high-temperature billet to remove the oxide scale.

[0069] Forging forming:

[0070] Select the free forging process to preliminarily forge the heated billet into a dumbbell billet and keep the temperature stable.

[0071] Surface treatment:

[0072] Use an air compressor to blow air to clean the surface of the high-temperature billet and the inside of the pre-forging die, and to clean the oxide scale on the surface of the rough billet after forging.

[0073] The forgings are cut and annealed to make the material structure more uniform.

[0074] Casting and molding:

[0075] The processed billet is heated to 650°C, melted and poured into a casting mold for cooling.

[0076] Use a shot blasting machine for surface treatment to remove excess aluminum alloy around the swing arm during the casting process.

[0077] Heat Treatment:

[0078] The cast swing arm is heated to 525°C and quenched, and the cooling rate is controlled below 45°C / s.

[0079] Assembly:

[0080] Fix the ball pin vertically on the surface of the ball seat and install the protective cover.

[0081] Press rings are embedded in the ports of the first bushing, the second bushing and the hydraulic bushing.

[0082] Embodiment 3:

[0083] The embodiment of the present invention provides a low-temperature embodiment of a low-energy consumption and high-efficiency forging method for a truck swing arm, comprising:

[0084] Material selection and preparation:

[0085] 6061 aluminum alloy bar was selected, and the composition and mass percentage were: Si: 0.59%, Fe: 0.36%, Cu: 0.21%, Mn: 0.09%, Mg: 0.90%, Cr: 0.12%, Zn: 0.11%, Ti: 0.09%, and the balance was aluminum.

[0086] Weigh and prepare ingredients.

[0087] Heating and cleaning:

[0088] The double-length bar blank was heated to 800°C and kept warm, and then rapidly heated to 1100°C and kept for 2 hours.

[0089] Use an air compressor to blow air to clean the surface of the high-temperature billet to remove the oxide scale.

[0090] Forging forming:

[0091] Select the free forging process to preliminarily forge the heated billet into a dumbbell billet and keep the temperature stable.

[0092] Surface treatment:

[0093] Use an air compressor to blow air to clean the surface of the high-temperature billet and the inside of the pre-forging die, and to clean the oxide scale on the surface of the rough billet after forging.

[0094] The forgings are cut and annealed to make the material structure more uniform.

[0095] Casting and molding:

[0096] The processed blank is heated to 580°C, melted and poured into a casting mold for cooling.

[0097] Use a shot blasting machine for surface treatment to remove excess aluminum alloy around the swing arm during the casting process.

[0098] Heat Treatment:

[0099] The cast swing arm is heated to 520°C and quenched, and the cooling rate is controlled below 55°C / s.

[0100] Assembly:

[0101] Fix the ball pin vertically on the surface of the ball seat and install the protective cover.

[0102] Press rings are embedded in the ports of the first bushing, the second bushing and the hydraulic bushing.

[0103] Embodiment 4:

[0104] The embodiment of the present invention provides an optimized casting embodiment of a low-energy-consumption and high-efficiency forging method for a truck swing arm, comprising:

[0105] Material selection and preparation:

[0106] 6061 aluminum alloy bar was selected, and the composition and mass percentage were: Si: 0.61%, Fe: 0.34%, Cu: 0.23%, Mn: 0.10%, Mg: 0.91%, Cr: 0.09%, Zn: 0.10%, Ti: 0.10%, and the balance was aluminum.

[0107] Weigh and prepare ingredients.

[0108] Heating and cleaning:

[0109] The double-length bar blank was heated to 800°C and kept warm, and then rapidly heated to 1180°C and kept for 1.5 hours.

[0110] Use an air compressor to blow air to clean the surface of the high-temperature billet to remove the oxide scale.

[0111] Forging forming:

[0112] Select the free forging process to preliminarily forge the heated billet into a dumbbell billet and keep the temperature stable.

[0113] Surface treatment:

[0114] Use an air compressor to blow air to clean the surface of the high-temperature billet and the inside of the pre-forging die, and to clean the oxide scale on the surface of the rough billet after forging.

[0115] The forgings are cut and annealed to make the material structure more uniform.

[0116] Casting and molding:

[0117] The processed billet is heated to 640°C, melted and poured into a casting mold for cooling.

[0118] Use a shot blasting machine for surface treatment to remove excess aluminum alloy around the swing arm during the casting process.

[0119] Heat Treatment:

[0120] The cast swing arm is heated to 525°C and quenched, and the cooling rate is controlled below 48°C / s.

[0121] Assembly:

[0122] Fix the ball pin vertically on the surface of the ball seat and install the protective cover.

[0123] Press rings are embedded in the ports of the first bushing, the second bushing and the hydraulic bushing.

[0124] Embodiment 5:

[0125] The embodiment of the present invention provides a high-efficiency embodiment of a low-energy-consumption and high-efficiency forging method for a truck swing arm, comprising:

[0126] Material selection and preparation:

[0127] 6061 aluminum alloy bar was selected, and the composition and mass percentage were: Si: 0.58%, Fe: 0.35%, Cu: 0.20%, Mn: 0.09%, Mg: 0.94%, Cr: 0.08%, Zn: 0.11%, Ti: 0.10%, and the balance was aluminum.

[0128] Weigh and prepare ingredients.

[0129] Heating and cleaning:

[0130] The double-length bar blank was heated to 800°C and kept warm, and then rapidly heated to 1150°C and kept for 2 hours.

[0131] Use an air compressor to blow air to clean the surface of the high-temperature billet to remove the oxide scale.

[0132] Forging forming:

[0133] Select the free forging process to preliminarily forge the heated billet into a dumbbell billet and keep the temperature stable.

[0134] Surface treatment:

[0135] Use an air compressor to blow air to clean the surface of the high-temperature billet and the inside of the pre-forging die, and to clean the oxide scale on the surface of the rough billet after forging.

[0136] The forgings are cut and annealed to make the material structure more uniform.

[0137] Casting and molding:

[0138] The processed billet is heated to 630°C, melted and poured into a casting mold for cooling.

[0139] Use a shot blasting machine for surface treatment to remove excess aluminum alloy around the swing arm during the casting process.

[0140] Heat Treatment:

[0141] The cast swing arm is heated to 525°C and quenched, and the cooling rate is controlled below 50°C / s.

[0142] Assembly:

[0143] Fix the ball pin vertically on the surface of the ball seat and install the protective cover.

[0144] Press rings are embedded in the ports of the first bushing, the second bushing and the hydraulic bushing.

[0145] Comparative experimental design:

[0146] In order to verify the superiority of the method of the present invention compared with the traditional method, the following comparative experiment was designed.

[0147] Experiment 1: Comparison of material properties:

[0148] The mechanical properties (tensile strength, yield strength, elongation) of comparative examples 1-5 and conventional steel swing arms are as shown in Table 1 below:

[0149] Example Tensile strength(MPa) Yield strength (MPa) Elongation(%) Traditional steel 450 300 20 Example 1 485 320 18 Example 2 500 330 19 Example 3 480 315 17 Example 4 495 325 18 Example 5 490 320 18

[0150] Table 1

[0151] Experiment 2: Energy consumption comparison:

[0152] The energy consumption of comparative examples 1-5 and the traditional steel swing arm is as shown in Table 2 below:

[0153] Example Energy consumption (kWh) Traditional steel 120 Example 1 90 Example 2 88 Example 3 92 Example 4 89 Example 5 91

[0154] Table 2

[0155] Experiment 3: Production efficiency comparison:

[0156] The production efficiency (number of swing arms produced per unit time) of comparative examples 1-5 and conventional steel swing arms is shown in Table 3 below:

[0157]

[0158]

[0159] Table 3

[0160] in conclusion:

[0161] By comparing the experimental data, it can be clearly seen that the low-energy and high-efficiency forging method of the present invention is superior to the production method of the traditional carbon steel swing arm in terms of material properties, energy consumption and production efficiency. The present invention performs well in terms of performance improvement and energy consumption reduction in various aspects;

[0162] 1. Material properties:

[0163] The tensile strength, yield strength and elongation of Examples 1-5 are significantly higher than those of conventional steels. The tensile strength is up to 500 MPa, the yield strength is up to 330 MPa, and the elongation is maintained between 17% and 19%, which are all better than conventional steels (tensile strength 450 MPa, yield strength 300 MPa, and elongation 20%). This performance improvement means that in practical applications, the swing arm of the present invention can better withstand high loads and complex stress conditions, thereby improving service life and safety.

[0164] 2. Energy consumption:

[0165] The energy consumption of Examples 1-5 is significantly lower than that of traditional steel. The energy consumption of traditional steel is 120 kWh, while the energy consumption of the embodiments can reach 88 kWh at the lowest and 92 kWh at the highest. This makes the present invention more energy-efficient and environmentally friendly during the production process, and can effectively reduce manufacturing costs and carbon emissions.

[0166] 3.Production efficiency:

[0167] The production efficiency of Examples 1-5 is higher than that of conventional steel. The production efficiency of conventional steel is 50 pieces per hour, while the highest of the examples is 75 pieces, and the lowest is 68 pieces. The improvement of production efficiency means that more swing arms can be produced in the same time, thereby improving the production capacity and economic benefits of the production line.

[0168] Aluminum alloy material selection:

[0169] Aluminum alloys are composed of Si, Fe, Cu, Mn, Mg, Cr, Zn, Ti and other elements, and have excellent mechanical properties and machinability. These alloy elements form fine precipitates during the forging process, which hinder the movement of grain boundaries and improve the strength and hardness of the alloy. In addition, aluminum alloy materials are lighter than traditional carbon steel, which reduces the burden on the wheels and improves fuel efficiency.

[0170] Two-stage heating method:

[0171] The two-stage heating method first keeps the material at 800°C to eliminate the internal stress of the material, and then quickly heats it to 1100-1200°C to make the material reach the optimal plastic state. This process not only reduces oxidation loss and shortens the heating time, but also prevents cracks caused by poor thermal conductivity, thereby improving the quality of forgings.

[0172] Air compressor cleaning technology:

[0173] The high-temperature billet surface is cleaned by air blowing with an air compressor to remove the oxide scale on the surface. This process reduces the damage of the oxide scale to the die and forging surface, improves the surface quality, extends the service life of the die, and reduces the difficulty of subsequent processing.

[0174] Free forging process:

[0175] The free forging process makes full use of materials in the forging process and reduces material waste. The shape of the dumbbell billet after forging is close to the shape of the final product, which reduces the amount of subsequent processing and improves production efficiency.

[0176] Annealing and quenching heat treatment:

[0177] Annealing treatment makes the material structure more uniform and improves its machinability. Quenching treatment improves the internal structural strength of aluminum alloy and avoids cracks during the cooling process by controlling the cooling rate, thereby improving the product's qualification rate and mechanical properties.

[0178] Shot blasting surface treatment:

[0179] Shot blasting removes excess aluminum alloy around the swing arm during casting, making the surface smoother. This process not only improves the aesthetics of the product, but also facilitates subsequent processing and recycling of excess materials, improving material utilization.

[0180] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low energy consumption and high efficiency forging method for a truck swing arm, characterized in that: The following steps are involved: S1. Material selection and preparation: Select aluminum alloy bars that meet the use requirements and weigh and prepare the materials; S2. Heating and cleaning: Use double-sized billets for feeding, heat the billets to 1150-1320°C, and clean the oxide scale on the surface of the billets; S3, forging: select the free forging process, process the heated billet into a dumbbell billet, and keep it warm; S4, surface treatment: clean the oxide scale on the surface of the rough billet after forging, and perform cutting and annealing heat treatment; S5, casting and molding: melt the treated blank, pour it into a casting mold, take it out after cooling, and perform shot blasting surface treatment; S6. Heat treatment: heat the cast swing arm to 510-535°C, perform quenching treatment, and control the cooling rate to be below 50°C / s; S7. Assembly: Install the accessories of the swing arm after heat treatment, including the ball pin, the first bushing, the second bushing and the hydraulic bushing.

2. A low energy consumption and high efficiency forging method for a truck swing arm according to claim 1, characterized in that: The composition and mass percentage of the aluminum alloy bar described in step S1 are: Si: 0.58-0.63%, Fe: 0.35%, Cu: 0.19-0.24%, Mn: 0.1%, Mg: 0.9-0.95%, Cr: 0.08-0.13%, Zn: 0.1%, Ti: 0.1%, and the remainder is Ai.

3. The low energy consumption and high efficiency forging method of a truck swing arm according to claim 1, characterized in that: The heating in step S2 adopts a two-stage heating method, including: S2.

1. Keep the temperature at 800℃ to eliminate the stress inside the material and ensure uniform heating; S2.

2. Rapidly heat to 1150-1320℃ and maintain for 0.8-2h to reach the temperature required for forging and improve the plasticity of the material.

4. The low energy consumption and high efficiency forging method for a truck swing arm according to claim 1, characterized in that: The cleaning described in step S2 includes: S2.

3. Use an air compressor to blow and clean the surface of the high-temperature billet to remove the oxide scale and improve the surface quality; S2.

4. Clean the oxide scale on the surface of the bar to prevent the oxide scale from damaging the mold and forgings in subsequent processes.

5. The low energy consumption and high efficiency forging method for a truck swing arm according to claim 1, characterized in that: The forging process described in step S3 includes: S3.

1. Select the free forging process to preliminarily forge the heated billet into a dumbbell billet close to the target shape; S3.

2. Keep the temperature of the dumbbell blank stable to avoid hardening and deformation caused by material cooling and ensure forging quality.

6. The low energy consumption and high efficiency forging method of a truck swing arm according to claim 1, characterized in that: The surface treatment in step S4 includes: S4.

1. Use air compressor to clean the surface of high-temperature billet and the inside of pre-forging die to prevent oxide scale from accelerating die wear; S4.

2. Cut the forgings and perform annealing heat treatment to make the material structure more uniform and improve its subsequent processing performance.

7. The low energy consumption and high efficiency forging method for a truck swing arm according to claim 1, characterized in that: The casting and molding described in step S5 include: S5.

1. Heat the treated blank to 565-675°C to make the aluminum alloy molten for easy casting; S5.

2. Pour the molten aluminum alloy into a casting mold for cooling, and produce multiple products at one time through the mold to reduce manufacturing costs.

8. The low energy consumption and high efficiency forging method for a truck swing arm according to claim 1, characterized in that: The surface treatment in step S5 includes: S5.

3. Use a shot blasting machine to perform surface treatment to remove excess aluminum alloy around the swing arm during the casting process to ensure surface smoothness; S5.

4. Remove excess aluminum alloy during the casting process to obtain a separate aluminum alloy swing arm, which is convenient for subsequent processing and material recycling.

9. The low energy consumption and high efficiency forging method for a truck swing arm according to claim 1, characterized in that: The heat treatment in step S6 includes: S6.

1. Heat the cast swing arm to 510-535℃ and perform quenching treatment to ensure uniform internal structure of the material; S6.

2. Control the cooling rate below 50℃ / s to improve the internal structural strength of the aluminum alloy and avoid cracks during the cooling process.

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