High-magnesium light-strength high-performance heavy-load aluminum alloy wheel hub and manufacturing method thereof

Abstract

The application discloses a high-magnesium light-strength high-performance heavy-load aluminum alloy wheel hub and a manufacturing method thereof, and comprises the following steps: S1) high-magnesium alloy proportioning, alloy raw materials are proportioned according to mass percentage, the content of magnesium is 7.0%-9.0%, the content of silicon is 0.2%-0.4%, the content of copper is 0.1%-0.3%, the content of manganese is 0.3%-0.6%, the content of titanium is 0.08%-0.15%, and the balance is industrial pure aluminum; each component raw material is accurately weighed, and the alloy component proportioning error is ensured to be controlled within ±0.02%. Compared with a traditional medium-low-magnesium aluminum alloy formula, the magnesium element proportion is reasonably increased, a plurality of trace elements are matched, the alloy matrix structure is effectively optimized, the matrix overall structure strength is significantly improved while realizing the light weight of the wheel hub, and thus the industry defects that the traditional aluminum alloy wheel hub cannot simultaneously achieve light weight and bearing strength are solved; the matrix stability is stronger, and the bearing use conditions of various heavy-load vehicles can be stably adapted.

Description

Technical Field

[0001] This invention relates to the field of wheel manufacturing technology, specifically to a high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel and its manufacturing method. Background Technology

[0002] Currently, aluminum alloy wheels have widely replaced steel wheels due to their advantages such as lightweight, excellent thermal conductivity, high forming precision, and superior appearance, becoming an important load-bearing component for passenger cars, commercial vehicles, and some special heavy-duty vehicles. The existing conventional manufacturing process for aluminum alloy wheels mainly uses conventional low-magnesium aluminum alloy raw materials, undergoing standardized processes including uniform proportioning and melting, one-time homogeneous heat treatment, fixed-parameter forging, ordinary solution aging treatment, and single anodizing surface protection. This process is highly mature and can meet the basic driving, load-bearing, and wear-resistant requirements of conventional vehicles under ordinary road conditions, making it the mainstream mass production technology for wheels in the industry.

[0003] However, the conventional manufacturing processes for traditional aluminum alloy wheels have limited adaptability and significant overall technological limitations, making them unsuitable for the harsh service conditions of heavy loads, high corrosion, and high-intensity bumps. Current mainstream processes mostly employ general-purpose low-to-medium magnesium alloy formulations and standardized processing procedures, with lax control over alloy composition ratios. This makes it difficult to balance lightweighting and structural strength, resulting in a relatively low upper limit for the overall mechanical properties of the finished wheel. Furthermore, the traditional smelting, forming, heat treatment, and surface treatment processes lack refinement, resulting in inadequate control over melt purity, poor uniformity of the ingot's internal structure, and a tendency for residual internal stress after forming. This can easily lead to deformation, cracking, and fatigue damage in the wheel during long-term heavy-load operation. In addition, traditional surface protection processes offer limited protection levels, resulting in weak corrosion and wear resistance in the finished wheel, and a short service life, failing to meet the high-strength, long-life service standards of heavy-duty special vehicles and engineering vehicles.

[0004] In summary, existing aluminum alloy wheel manufacturing processes suffer from significant performance shortcomings, poor adaptability to operating conditions, and insufficient stability and service life of finished products. The conventional aluminum alloy wheels produced have limited overall performance and cannot meet the high-performance requirements of high-end heavy-duty vehicles. Therefore, there is an urgent need for a high-magnesium aluminum alloy wheel manufacturing process that optimizes the entire process from raw materials, smelting, forming to surface treatment, thereby improving wheel strength, density, and durability to meet the requirements of mass production in heavy-duty scenarios. Summary of the Invention

[0005] The purpose of this invention is to provide a high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub and its manufacturing method, so as to solve the problems existing in the current aluminum alloy wheel hub manufacturing process mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for manufacturing a high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub, comprising the following steps:

[0007] S1) High magnesium alloy ratio

[0008] The alloy raw materials are prepared according to the following mass percentages: magnesium content is 7.0%–9.0%, silicon 0.2%–0.4%, copper 0.1%–0.3%, manganese 0.3%–0.6%, titanium 0.08%–0.15%, and the balance is industrial pure aluminum. Each component raw material is weighed precisely to ensure that the alloy composition ratio error is controlled within ±0.02%.

[0009] S2) Protective smelting and refining

[0010] The industrial pure aluminum prepared in step S1 is put into a melting furnace and heated to 720-750℃ until it is completely melted. When the furnace temperature is kept constant at 750℃, silicon, copper, manganese and titanium components are added. After holding at this temperature for 5-8 minutes, the temperature is lowered to 730℃, and then magnesium components are added. Argon gas is continuously introduced throughout the process for protection. After melting, a refining agent is added and the mixture is rotary refined for 10-15 minutes. After standing for 20-30 minutes, the melt is filtered as a whole using a 200-250 mesh ceramic filter plate to obtain aluminum alloy melt.

[0011] S3) Homogenization Pretreatment of Ingots

[0012] The melt obtained in step S2 is cast into a precast wheel hub ingot, with the casting temperature controlled at 700-720℃. The ingot is then sent to a homogenizing heat treatment furnace, where it is heated in stages with gradient heating and holding. First, the temperature is raised to 420-440℃ and held for 4-6 hours, then raised to 480-495℃ and held for 8-10 hours. Subsequently, the furnace body is cooled to 350-360℃ and held isothermally for 2 hours. After homogenization, the ingot is cooled to room temperature using a water mist cooling method.

[0013] S4) Forging and Rotation Composite Forming

[0014] The pre-treated wheel hub precast ingots are preheated to 380–410℃ and held for 2–3 hours to ensure uniform temperature. A 6000–8000 ton hydraulic forging press is used for segmented pressure forging, with a pre-forging pressure of 45–55 MPa and a holding pressure of 3–5 seconds, and a final forging pressure of 65–75 MPa and a holding pressure of 8–12 seconds to form the wheel hub rough blank. A CNC spinning machine is used for zoned differential speed spinning, with a constant feed rate of 1.0–1.2 mm / r and a spinning speed of 80–100 r / min for the rim section, and a constant feed rate of 0.8–1.0 mm / r and a spinning speed of 50–70 r / min for the spoke section, maintaining a constant spinning temperature of 350–380℃ throughout the process.

[0015] S5) Gradient strengthening heat treatment

[0016] The formed wheel hub blank is first subjected to low-temperature stress relief pretreatment, heated to 100-120℃ and held for 1-2 hours; then subjected to solution treatment, heated to 475-485℃ and held for 2.5-3.5 hours, followed by rapid water quenching; finally subjected to two-stage aging treatment, with the first stage aging at 120-140℃ and held for 3-4 hours, and the second stage aging at 170-190℃ and held for 5-6 hours.

[0017] S6) Surface composite strengthening treatment

[0018] The heat-treated wheel blanks are subjected to micro-arc oxidation, pure water washing and purification, and hard anodizing in sequence. The water washing and purification process uses circulating pure water spray cleaning with a spray pressure of 0.2-0.4 MPa and a cleaning time of 3-5 minutes to generate a composite protective coating on the wheel surface, resulting in a finished high-magnesium, lightweight, heavy-duty aluminum alloy wheel.

[0019] Preferably, in step S2, the refining agent is an aluminum-titanium-boron composite refining agent or an aluminum-zirconium-carbon composite refining agent. Under conventional preparation conditions, the aluminum-titanium-boron composite refining agent is selected, while under high-purity preparation conditions, the aluminum-zirconium-carbon composite refining agent is selected.

[0020] The conventional preparation conditions refer to the mass production conditions that meet the conventional mechanical properties and purity requirements of wheel hubs for ordinary passenger cars and light commercial vehicles, while the high purity preparation conditions refer to the high-end preparation conditions that meet the requirements of ultra-high density and ultra-low impurity content for wheel hubs for heavy-duty vehicles and special-operation vehicles.

[0021] The amount of refining agent added is 0.15% to 0.25% of the total mass of the alloy melt, and the argon gas flow rate is 8 to 12 L / min.

[0022] Preferably, in step S2, the ceramic filter plate is provided with a decreasing aperture structure along the melt flow direction, the aperture at the melt inlet end is larger than the aperture at the melt outlet end, and the melt filtration pressure is maintained at 0.08 to 0.12 MPa.

[0023] Preferably, in step S3, the cooling rate of the water mist slow cooling is controlled at 15-25℃ / min, and the grain size inside the ingot is uniformly controlled at 20-40μm after cooling.

[0024] Preferably, in step S4, the upper and lower dies are preheated simultaneously during die forging, and the die preheating temperature is 350-370℃.

[0025] Preferably, in step S4, the time interval between the completion of the die forging process and the start of the spinning process does not exceed 15 minutes, and the operating environment temperature of the two processes is constantly controlled at 300-350℃.

[0026] Preferably, in step S5, the water quenching cooling rate is ≥80℃ / s, and the water temperature after water quenching is ≤40℃.

[0027] Preferably, in step S6, after the water washing and purification process is completed and before the hard anodizing process is started, a 5-10 minute room temperature air drying and settling process is added, and the air drying operation adopts a dust-free and closed working environment.

[0028] Preferably, in step S6, the micro-arc oxidation treatment voltage is 400-450V, and the treatment is continued for 15-20 minutes until a ceramic protective layer with a thickness of 8-12μm is formed on the surface of the wheel hub, after which the processing is stopped.

[0029] A high-magnesium, lightweight, high-strength, high-performance heavy-duty aluminum alloy wheel hub, wherein the high-magnesium, lightweight, high-strength, high-performance heavy-duty aluminum alloy wheel hub is prepared by any of the above-described manufacturing methods.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1) Compared with the low magnesium aluminum alloy formula in traditional technology, this application can effectively optimize the microstructure of the alloy matrix by reasonably increasing the magnesium content and strengthening it with a variety of trace elements. While achieving lightweight wheel hub, it also improves the overall structural strength of the matrix, thus solving the technical problem that traditional aluminum alloy wheel hub cannot balance lightweight and load-bearing strength. This makes the matrix more stable and can be stably adapted to the load-bearing conditions of various heavy-duty vehicles.

[0032] 2) This application optimizes the smelting, refining, and ingot homogenization processes by using step-by-step feeding, temperature-controlled smelting, and gradient pore size filtration. This effectively improves the defects of high-magnesium alloy melts, such as easy oxidation and inclusion, and enhances melt purity. It reduces internal defects such as porosity, looseness, and segregation in ingots from the source. Furthermore, the combination of segmented gradient homogenization heat preservation and water mist slow cooling processes can effectively refine ingot grains and homogenize the internal structure, thereby improving the overall density and structural stability of the ingot. This provides a reliable billet foundation for subsequent forming and performance enhancement, and reduces the defect rate of finished products.

[0033] 3) This application adopts a zoned differentiated forging and rotary forming combined with gradient composite heat treatment process. The forming parameters are adapted to the different structural stress characteristics of the wheel hub. Combined with the short-interval constant temperature continuous operation mode, the overall forming accuracy and structural uniformity of the wheel hub can be improved. At the same time, through low temperature stress relief pretreatment combined with solution treatment and two-stage aging segmented heat treatment, the residual internal stress of forming can be fully released and the distribution of alloy precipitates can be precisely controlled, thereby improving the deformation resistance and fatigue durability of the wheel hub. It can be adapted to long-term service under complex and harsh working conditions such as heavy load and bumps.

[0034] 4) This application adopts a composite surface strengthening process combining micro-arc oxidation and hard anodizing, and uses spray purification and dust-free closed air drying processes to replace the single surface treatment method in traditional technology. By controlling process parameters, a composite ceramic protective coating with uniform thickness and tight bonding is prepared, which improves the wear resistance, corrosion resistance and salt spray resistance of the wheel hub surface. This avoids problems such as rust, coating peeling and surface wear of the wheel hub under complex outdoor and corrosive conditions, effectively extending the overall service life of the finished wheel hub and broadening the product's adaptability to various working conditions. Attached Figure Description

[0035] Figure 1 This is a flowchart of the manufacturing method of this application. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of the invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of the invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] In the description of the invention, it should be noted that the execution order of the steps is not limited by the sequence number. The possible changes in the order of some steps, the synchronous execution of steps, and the split execution of steps are all within the scope of protection of this application.

[0040] Please see Figure 1This invention provides a technical solution: a method for manufacturing a high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub, comprising the following steps:

[0041] S1) High magnesium alloy ratio

[0042] The alloy raw materials are prepared according to the following mass percentages: magnesium content is 7.0%–9.0%, silicon 0.2%–0.4%, copper 0.1%–0.3%, manganese 0.3%–0.6%, titanium 0.08%–0.15%, and the balance is industrial pure aluminum. Each component raw material is weighed precisely to ensure that the alloy composition ratio error is controlled within ±0.02%.

[0043] S2) Protective smelting and refining

[0044] The industrial pure aluminum prepared in step S1 is put into a melting furnace and heated to 720-750℃ until it is completely melted. When the furnace temperature is kept constant at 750℃, silicon, copper, manganese and titanium components are added. After holding at this temperature for 5-8 minutes, the temperature is lowered to 730℃, and then magnesium components are added. Argon gas is continuously introduced throughout the process for protection. After melting, a refining agent is added and the mixture is rotary refined for 10-15 minutes. After standing for 20-30 minutes, the melt is filtered as a whole using a 200-250 mesh ceramic filter plate to obtain aluminum alloy melt.

[0045] S3) Homogenization Pretreatment of Ingots

[0046] The melt obtained in step S2 is cast into a precast wheel hub ingot, with the casting temperature controlled at 700-720℃. The ingot is then sent to a homogenizing heat treatment furnace, where it is heated in stages with gradient heating and holding. First, the temperature is raised to 420-440℃ and held for 4-6 hours, then raised to 480-495℃ and held for 8-10 hours. Subsequently, the furnace body is cooled to 350-360℃ and held isothermally for 2 hours. After homogenization, the ingot is cooled to room temperature using a water mist cooling method.

[0047] S4) Forging and Rotation Composite Forming

[0048] The pre-treated wheel hub precast ingots are preheated to 380–410℃ and held for 2–3 hours to ensure uniform temperature. A 6000–8000 ton hydraulic forging press is used for segmented pressure forging, with a pre-forging pressure of 45–55 MPa and a holding pressure of 3–5 seconds, and a final forging pressure of 65–75 MPa and a holding pressure of 8–12 seconds to form the wheel hub rough blank. A CNC spinning machine is used for zoned differential speed spinning, with a constant feed rate of 1.0–1.2 mm / r and a spinning speed of 80–100 r / min for the rim section, and a constant feed rate of 0.8–1.0 mm / r and a spinning speed of 50–70 r / min for the spoke section, maintaining a constant spinning temperature of 350–380℃ throughout the process.

[0049] S5) Gradient strengthening heat treatment

[0050] The formed wheel hub blank is first subjected to low-temperature stress relief pretreatment, heated to 100-120℃ and held for 1-2 hours; then subjected to solution treatment, heated to 475-485℃ and held for 2.5-3.5 hours, followed by rapid water quenching; finally subjected to two-stage aging treatment, with the first stage aging at 120-140℃ and held for 3-4 hours, and the second stage aging at 170-190℃ and held for 5-6 hours.

[0051] S6) Surface composite strengthening treatment

[0052] The heat-treated wheel blanks are subjected to micro-arc oxidation, pure water washing and purification, and hard anodizing in sequence. The water washing and purification process uses circulating pure water spray cleaning with a spray pressure of 0.2-0.4 MPa and a cleaning time of 3-5 minutes to generate a composite protective coating on the wheel surface, resulting in a finished high-magnesium, lightweight, heavy-duty aluminum alloy wheel.

[0053] Specifically, this application utilizes a multi-step processing system—including precise high-magnesium alloy proportioning, step-by-step protective melting, gradient homogenization pretreatment, differentiated forging and spinning composite forming, multi-stage gradient heat treatment, and composite surface strengthening treatment—to create an integrated processing system suitable for heavy-duty wheel hub production. This application strictly controls critical process parameters such as temperature, pressure, duration, and rotation speed at each stage, while standardizing raw material proportioning accuracy and processing standards at each stage. This allows for comprehensive optimization of wheel hub production quality from raw material preparation, billet forming, performance enhancement to surface protection, effectively improving the matrix density, structural strength, forming accuracy, and surface protection performance of aluminum alloy wheels. The resulting wheels possess both lightweight and high load-bearing characteristics, enabling stable adaptation to diverse driving conditions in ordinary passenger cars, commercial vehicles, and heavy-duty special vehicles, significantly expanding the product's application scenarios and improving its overall stability and service life.

[0054] Example 1

[0055] This embodiment provides a method for manufacturing a high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub. The specific preparation steps are as follows:

[0056] S1) High magnesium alloy ratio

[0057] The alloy raw materials are precisely configured according to mass percentages, with fixed contents of each component: magnesium 8.0%, silicon 0.3%, copper 0.2%, manganese 0.45%, titanium 0.12%, and the balance being industrial pure aluminum; all raw materials are precisely weighed, and the alloy composition ratio error is strictly controlled within ±0.02% to ensure the accuracy and stability of the raw material composition.

[0058] S2) Protective smelting and refining

[0059] The industrial pure aluminum, after being proportioned, is added to a melting furnace and heated to 735°C until completely melted. Once the furnace temperature is maintained at a constant 750°C, silicon, copper, manganese, and titanium components are added sequentially. After holding at this temperature for 6 minutes, the temperature is lowered to 730°C, and then magnesium is added. Argon gas is continuously introduced throughout the melting process to create a protective atmosphere and prevent oxidation and burn-off of the alloy melt. After the raw materials are completely melted, an aluminum-zirconium-carbon composite refining agent is added for rotary refining. The amount of refining agent added is 0.20% of the total mass of the alloy melt, and the argon gas flow rate is controlled at 10 L / min. Rotary refining is continued for 12 minutes. After refining, the mixture is allowed to stand for 25 minutes, and then the melt is filtered through a 220-mesh ceramic filter plate. The ceramic filter plate has a decreasing pore size structure along the melt flow direction, with the inlet pore size larger than the outlet pore size. The melt filtration pressure is maintained at 0.10 MPa throughout the process, ultimately yielding a high-purity aluminum alloy melt. This embodiment is suitable for the high-purity preparation of wheel hubs for heavy-duty vehicles and special-operation vehicles.

[0060] S3) Homogenization Pretreatment of Ingots

[0061] The aluminum alloy melt prepared by S2 was cast into precast wheel hub ingots, with the casting temperature stably controlled at 710℃. The precast ingots were then sent to a homogenizing heat treatment furnace for staged gradient heating and holding treatment. First, the temperature was raised to 430℃ and held for 5 hours, then raised to 490℃ and held for 9 hours. Subsequently, the furnace temperature was lowered to 355℃ and held isothermally for 2 hours. After homogenization treatment, the ingots were cooled to room temperature by water mist slow cooling at a rate of 20℃ / min. After cooling, the grain size inside the ingots was uniform and stable at 30μm, resulting in precast ingots with uniform structure and good density.

[0062] S4) Forging and Rotation Composite Forming

[0063] The pre-treated wheel hub ingots were preheated to 395℃ and held for 2.5 hours to ensure uniform temperature throughout the ingot. A 7000-ton hydraulic forging press was used for segmented pressure-holding die forging. The upper and lower dies were preheated simultaneously during die forging, with the die preheating temperature controlled at 360℃. The pre-forging pressure was 50MPa with a holding time of 4 seconds, and the final forging pressure was 70MPa with a holding time of 10 seconds, resulting in a rough wheel hub blank. After the die forging process, the interval between processes was controlled at 12 minutes, and the ambient temperature for both processes was maintained at a constant 320℃. A CNC spinning machine was used for differentiated speed spinning in different zones. The rim section had a constant feed rate of 1.1mm / r and a spinning speed of 90r / min, while the spoke section had a constant feed rate of 0.9mm / r and a spinning speed of 60r / min. The spinning temperature was maintained at a constant 365℃ throughout the process, completing the wheel hub forging-spinning composite forming process.

[0064] S5) Gradient strengthening heat treatment

[0065] The formed wheel hub blank is subjected to gradient strengthening heat treatment. First, a low-temperature stress relief pretreatment is performed, which is heated to 110℃ and held for 1.5 hours. Then, a solution treatment is carried out, which is heated to 480℃ and held for 3 hours. After that, it is rapidly water-quenched at a rate of 85℃ / s, and the water temperature is stabilized at 35℃ after water quenching. Finally, a two-stage aging treatment is performed, with the first stage aging at 130℃ and held for 3.5 hours, and the second stage aging at 180℃ and held for 5.5 hours, to complete the overall performance strengthening of the wheel hub.

[0066] S6) Surface composite strengthening treatment

[0067] The heat-treated wheel blanks are subjected to micro-arc oxidation, pure water washing and purification, and hard anodizing in sequence. The water washing and purification process uses circulating pure water spray cleaning at a pressure of 0.3 MPa for 4 minutes. After the water washing and purification process, an 8-minute room temperature air drying and settling process is added, which is completed in a dust-free and sealed environment. Then, micro-arc oxidation is performed with a voltage controlled at 420V for 18 minutes. After a 10μm thick ceramic protective layer is formed on the wheel surface, the processing is stopped. Finally, hard anodizing is performed to generate a uniform and dense composite protective coating on the wheel surface, ultimately producing a high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel.

[0068] I. Description of Finished Product Testing Method in Example 1

[0069] The high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hubs prepared in this embodiment were sampled and tested. All test items were conducted in accordance with the current national aluminum alloy wheel hub testing standards and under normal temperature and pressure conditions. The grain structure, mechanical properties, surface coating properties, fatigue resistance and corrosion resistance of the finished products were comprehensively tested. The test conditions for each item were stable and uniform, and the corresponding measured data were recorded to complete the evaluation of the physical and chemical properties of the finished products.

[0070] II. Example 1: Test Data Table of Physicochemical Indicators of Finished Product

[0071] Test Project Test Standards Test conditions Test Results Matrix grain size GB / T 3246.1-2012 Metallographic section observation of the center part of the wheel hub and spokes, taken at room temperature. 30μm, uniform grain structure with no coarse segregation tensile strength GB / T 228.1-2021 Static tensile test at room temperature, standard tensile specimen 428MPa Yield strength GB / T 228.1-2021 Static tensile test at room temperature, standard tensile specimen 365MPa Elongation after fracture GB / T 228.1-2021 Static tensile test at room temperature, gauge length 50 mm 14.2% matrix hardness GB / T 4340.1-2009 Vickers hardness testing, with testing points taken evenly on the working surface. 138HV Ceramic protective layer thickness GB / T 4957-2003 Eddy current thickness gauge for multi-point inspection of wheel hub surface 10μm, uniform thickness without deviation neutral salt spray test GB / T 10125-2021 5% NaCl solution, spray duration 1000h No rust, no coating peeling, no pitting corrosion Wheel hub bending fatigue performance GB / T 5334-2014 Rated load condition, continuous cyclic bending test No cracks or deformation after ≥1.2 million cycles Melt purity (inclusion level) GB / T 7999-2015 After smelting, samples of the melt are taken to test the inclusion content. Inclusion level ≤ 0.5, excellent melt purity.

[0072] III. Test Results

[0073] Multiple tests and verifications have shown that the aluminum alloy wheel hub prepared in this embodiment has a uniform and dense matrix grain structure, free from internal defects such as segregation, porosity, and pores. The product exhibits excellent core mechanical properties such as tensile strength, yield strength, elongation, and hardness, demonstrating outstanding structural load-bearing capacity and resistance to deformation. Furthermore, the composite protective coating on the finished product surface is of uniform thickness and firmly bonded, possessing excellent corrosion resistance and fatigue resistance. It can withstand harsh service conditions such as heavy loads, complex bumps, and salt spray corrosion for extended periods. Its overall comprehensive performance far surpasses that of conventional aluminum alloy wheel hubs, fully meeting the high-end usage standards and mass production quality requirements for wheel hubs used in heavy-duty vehicles and special-purpose vehicles.

[0074] In step S2, the refining agent is an aluminum-titanium-boron composite refining agent or an aluminum-zirconium-carbon composite refining agent. Under normal preparation conditions, the aluminum-titanium-boron composite refining agent is selected, while under high-purity preparation conditions, the aluminum-zirconium-carbon composite refining agent is selected.

[0075] Among them, the conventional preparation condition is the batch production condition that meets the conventional mechanical properties and purity requirements of wheel hubs for ordinary passenger cars and light commercial vehicles, while the high purity preparation condition is the high-end preparation condition that meets the requirements of ultra-high density and ultra-low impurity content for wheel hubs for heavy-duty vehicles and special operation vehicles.

[0076] The amount of refining agent added is 0.15% to 0.25% of the total mass of the alloy melt, and the argon gas flow rate is 8 to 12 L / min.

[0077] Specifically, conventional refining agents are used for the mass production of wheel hubs for ordinary civilian vehicles. This ensures basic production quality while meeting the needs of large-scale mass production, improving production efficiency and controlling production costs. For the high-end production of wheel hubs for heavy-duty and special-purpose vehicles, specialized refining agents are used to further remove trace impurities and oxide inclusions from the alloy melt, improve melt purity, optimize the microstructure of the alloy matrix, and give the wheel hub blank higher density and structural uniformity. This meets the requirements of ultra-high mechanical performance and long-term stable service for high-end heavy-duty wheel hubs, thereby achieving a balance between production economy and product high performance.

[0078] Example 2 (Standard Operating Conditions)

[0079] This embodiment provides a manufacturing method for high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheels. This is a preferred process solution suitable for conventional mass production, meeting the high-quality mass production needs of wheels for ordinary passenger cars and light-duty commercial vehicles. The specific preparation steps are as follows:

[0080] S1) High magnesium alloy ratio: Same as in Example 1.

[0081] S2) Protective smelting and refining

[0082] The proportioned industrial pure aluminum is added to a melting furnace and heated to 735°C until completely melted. Once the furnace temperature is maintained at a constant 750°C, silicon, copper, manganese, and titanium components are added sequentially. After holding at this temperature for 6 minutes, the temperature is lowered to 730°C, and then magnesium is added. Argon gas is continuously introduced throughout the melting process to create a protective atmosphere and prevent oxidation and burn-off of the alloy melt. After the raw materials are completely melted, an aluminum-titanium-boron composite refining agent is added for rotary refining. The amount of refining agent added is 0.20% of the total mass of the alloy melt, and the argon gas flow rate is controlled at 10 L / min. Rotary refining is continued for 12 minutes. After refining, the mixture is allowed to stand for 25 minutes, and then the melt is filtered through a 220-mesh ceramic filter plate. The ceramic filter plate has a decreasing pore size structure along the melt flow direction, with the inlet pore size larger than the outlet pore size. The melt filtration pressure is maintained at 0.10 MPa throughout the process, ultimately yielding a high-purity aluminum alloy melt. This embodiment is suitable for the conventional high-quality manufacturing process of wheel hubs for ordinary passenger cars and light-duty commercial vehicles.

[0083] S3) Homogenization pretreatment of ingots: Same as in Example 1.

[0084] S4) Forging and turning composite forming: Same as Example 1.

[0085] S5) Gradient strengthening heat treatment: Same as in Example 1.

[0086] S6) Surface composite strengthening treatment: Same as in Example 1.

[0087] I. Description of Finished Product Testing Method in Example 2

[0088] The finished aluminum alloy wheel hubs prepared in this embodiment were sampled and tested. The testing environment, testing equipment, testing items and testing standards were consistent with those in Example 1. The grain structure, mechanical properties, surface coating properties, fatigue resistance and corrosion resistance were tested under normal temperature and pressure. The measured data were recorded and the performance evaluation was completed to ensure that the testing conditions of the two sets of embodiments were consistent and the data were comparable.

[0089] II. Example 2: Finished Product Physicochemical Index Test Data Table

[0090] Test Project Test Standards Test conditions Test Results Matrix grain size GB / T 3246.1-2012 Same as Example 1 The grain size is 30 μm, the grain structure is uniform, there is no obvious coarse segregation, and only a very small amount of fine impurities are present. tensile strength GB / T 228.1-2021 Same as Example 1 422MPa Yield strength GB / T 228.1-2021 Same as Example 1 358MPa Elongation after fracture GB / T 228.1-2021 Same as Example 1 13.8% matrix hardness GB / T 4340.1-2009 Same as Example 1 135HV Ceramic protective layer thickness GB / T 4957-2003 Same as Example 1 10μm, uniform thickness, with extremely small local deviations. neutral salt spray test GB / T 10125-2021 Same as Example 1 No rust or coating peeling; only very slight pinhole marks remain, which do not affect performance. Wheel hub bending fatigue performance GB / T 5334-2014 Same as Example 1 It underwent 1.12 million cycles without cracking or deformation. Melt purity (inclusion level) GB / T 7999-2015 Same as Example 1 Inclusion level 0.5, excellent melt purity.

[0091] III. Test Results

[0092] Testing and verification have shown that this embodiment is an optimal process scheme adapted to conventional manufacturing conditions. The overall manufacturing process is highly refined and standardized, resulting in a uniform and dense aluminum alloy wheel hub matrix with no internal defects such as porosity, air holes, or segregation. All mechanical and protective properties meet the standards for high-quality wheels. Compared to Embodiment 1, this embodiment only uses an aluminum-titanium-boron composite refining agent instead of an aluminum-zirconium-carbon composite refining agent, making it suitable for the high-quality mass production needs of ordinary passenger cars and light-duty commercial vehicles. While its overall performance is slightly lower than that of Embodiment 1 under heavy-duty special conditions, it is far superior to wheels manufactured using traditional conventional processes. Balancing product quality and mass production economy, this is the optimal process scheme for the mass production of conventional lightweight wheels, offering wide adaptability to various operating conditions and strong mass production stability.

[0093] In step S2, the ceramic filter plate is configured with a decreasing aperture structure along the melt flow direction, with the inlet aperture larger than the outlet aperture, and the melt filtration pressure maintained at 0.08–0.12 MPa. Specifically, the filter holes of the ceramic filter plate have a frustum-shaped structure. During installation, the larger opening is the inlet surface (contacting the liquid to be filtered), and the smaller opening is the outlet surface. During filtration, impurities are trapped on the inlet side; when backflushing is required, gas or liquid rushes in from the smaller opening, rapidly widening the channel and easily displacing clogged particles, preventing jamming. The frustum-shaped structure of the filter holes reduces the thickness resistance of the filter medium, achieving a higher initial throughput under the same pressure differential compared to straight holes. Furthermore, the frustum-shaped hole walls are thicker than straight holes, providing better thermal shock resistance and mechanical strength, making it suitable for high-temperature, high-pressure, or frequently backflushing conditions. This application, through its structural advantages, can comprehensively improve the overall purity of the aluminum alloy melt, avoid internal defects such as porosity, looseness, and inclusions in the ingot, effectively ensure the quality of the ingot forming, and steadily improve the mechanical properties of the finished wheel hub.

[0094] Comparative Example 1 (without gradient pore size filter structure, conventional constant pore size filter)

[0095] The preparation process for this comparative example is the same as that of Example 1, except that the gradient pore size structure and constant pressure filtration setting in the melt filtration process are omitted, and a conventional single-diameter ceramic filter plate is used for filtration. All other processes, process parameters, and control standards are the same as those in Example 1. The specific preparation steps are as follows:

[0096] S1) High magnesium alloy ratio: Same as in Example 1.

[0097] S2) Protective smelting and refining

[0098] The proportioned industrial pure aluminum was added to a melting furnace and heated to 735°C until completely melted. When the furnace temperature was maintained at a constant 750°C, silicon, copper, manganese, and titanium components were added sequentially. After holding at this temperature for 6 minutes, the temperature was lowered to 730°C, and then magnesium was added. Argon gas was continuously introduced throughout the melting process to form a protective atmosphere. After the raw materials were completely melted, an aluminum-zirconium-carbon composite refining agent was added for rotary refining. The amount of refining agent added was 0.20% of the total mass of the alloy melt, and the argon gas flow rate was controlled at 10 L / min. Rotary refining was continued for 12 minutes. After refining, the mixture was allowed to stand for 25 minutes. Then, a 220-mesh conventional equal-diameter ceramic filter plate was used to filter the entire melt. There was no gradient pore size structure setting or constant filtration pressure control, resulting in an aluminum alloy melt.

[0099] S3) Homogenization pretreatment of ingots: Same as in Example 1.

[0100] S4) Forging and turning composite forming: Same as Example 1.

[0101] S5) Gradient strengthening heat treatment: Same as in Example 1.

[0102] S6) Surface composite strengthening treatment: Same as in Example 1.

[0103] I. Comparative Example 1: Finished Product Testing Method Description

[0104] The sampling and testing environment, testing equipment, testing items, testing standards and testing conditions of this comparative example are completely consistent with those of Example 1, ensuring that the test data are highly comparable. The actual measurement, recording and analysis are only conducted on the changes in the performance of the finished product caused by the process difference.

[0105] II. Example 2: Finished Product Physicochemical Index Test Data Table

[0106] Test Project Test Standards Test conditions Test Results Matrix grain size GB / T 3246.1-2012 Same as Example 1 35μm, uneven grain distribution, with a small number of fine inclusions. tensile strength GB / T 228.1-2021 Same as Example 1 402MPa Yield strength GB / T 228.1-2021 Same as Example 1 338MPa Elongation after fracture GB / T 228.1-2021 Same as Example 1 12.5% matrix hardness GB / T 4340.1-2009 Same as Example 1 126HV Ceramic protective layer thickness GB / T 4957-2003 Same as Example 1 10μm, with significant local thickness deviation. neutral salt spray test GB / T 10125-2021 Same as Example 1 Localized pitting corrosion was observed, but there was no large-scale rust or coating peeling. Wheel hub bending fatigue performance GB / T 5334-2014 Same as Example 1 Fine fatigue lines appeared after 900,000 cycles, with no obvious deformation or cracking. Melt purity (inclusion level) GB / T 7999-2015 Same as Example 1 Inclusion level 1.5, melt purity is average.

[0107] III. Test Results

[0108] Testing and verification revealed that the comparative example, by eliminating the gradient pore size filter structure and constant pressure filtration process, resulted in decreased melt filtration accuracy. This meant that minute inclusions and impurities within the melt could not be completely removed, leading to poorer grain uniformity in the ingot and the presence of internal minute defects. Compared to Example 1, the finished product exhibited a significant decrease in various mechanical properties, fatigue life, and corrosion resistance. The overall density and stability of the finished product were insufficient, making it unsuitable for heavy-load, long-term service conditions. This demonstrates that the gradient pore size filter structure and constant pressure filtration process of this application play a crucial role in improving the overall performance of the wheel hub.

[0109] In step S3, the cooling rate of the water mist slow cooling is controlled at 15–25 °C / min, and the grain size inside the ingot is uniformly controlled at 20–40 μm after cooling. Specifically, the ingot after gradient homogenization treatment is cooled by a stable water mist slow cooling rate, which can avoid the problems of coarse grains, uneven structure, and internal stress concentration caused by rapid cooling, and can also avoid the disadvantages of low production efficiency caused by slow cooling. Through precise temperature control cooling, the grains inside the ingot can be continuously refined and evenly distributed, making the overall microstructure of the ingot more uniform, effectively improving the overall mechanical uniformity and structural stability of the ingot, providing a stable blank for subsequent forging and heat treatment, and avoiding the problems of insufficient local strength and easy deformation and cracking of the finished wheel hub due to differences in grain structure.

[0110] In step S4, the upper and lower dies are preheated simultaneously during die forging, with a preheating temperature of 350–370°C. Specifically, simultaneous preheating of the upper and lower dies ensures a uniform overall temperature of the dies, preventing temperature differences that could lead to uneven forming stress, thickness deviations, or material shortages in the wheel hub blank. A constant and suitable preheating temperature ensures that the aluminum alloy blank remains within a suitable plastic forming temperature range during die forging, improving the plastic fluidity of the blank and facilitating the full filling of the die cavity with metal. This effectively improves the forming accuracy and structural integrity of the wheel hub blank, while reducing forming defects during die forging and enhancing the overall forming quality and production qualification rate of the blank.

[0111] In step S4, the interval between the completion of the die forging process and the start of the spinning process shall not exceed 15 minutes, and the operating environment temperature for both processes shall be constantly controlled at 300-350℃. Specifically, the shorter interval between processes can effectively avoid problems such as sudden temperature drop, surface oxidation, and grain structure changes in the high-temperature blank after forming during the resting process. The constant operating environment temperature can continuously maintain the good plasticity of the blank, ensuring uniform flow of metal material and stable forming during the spinning process. This process setting can effectively reduce the residual internal stress during the forging-spinning connection process, ensure the forming consistency of various parts of the wheel hub rim and spokes, improve the overall structural density and mechanical property uniformity of the wheel hub, and strengthen the basic performance of the wheel hub in terms of deformation resistance and fatigue resistance.

[0112] In step S5, the water quenching cooling rate is ≥80℃ / s, and the water temperature after quenching is ≤40℃. Specifically, this application precisely controls the water quenching cooling rate and the water temperature after quenching during the water quenching process. This enables rapid and stable cooling after solution treatment. The ultra-high cooling rate allows the solid solution phase inside the alloy to quickly become supersaturated and remain in the matrix, significantly improving the strengthening effect of subsequent aging treatment. This effectively enhances the matrix strength and hardness of the aluminum alloy wheel hub. At the same time, strict control of the water temperature after quenching avoids the problems of cooling rate attenuation and weakening of the solution effect caused by excessively high water temperature. This ensures that the water quenching cooling effect of each batch of wheel hubs is uniform and the performance is stable, avoiding performance differences between batches. This guarantees the consistency and reliability of the mechanical properties of the finished wheel hubs and steadily improves the heavy load-bearing capacity of the wheel hubs.

[0113] In step S6, after the water washing and purification process is completed and before the hard anodizing process is started, a 5-10 minute room temperature air drying and settling process is added. The air drying operation adopts a dust-free and closed working environment. Specifically, this application adds a room temperature dust-free and closed air drying and settling process between the water washing and purification process and the hard anodizing process. This process can thoroughly remove residual sprayed water and trace impurities from the surface of the wheel hub. Since the surface of the wheel hub is prone to adhering free water and fine impurities after water washing, direct anodizing treatment will lead to defects such as insufficient coating adhesion, coating pinholes, and local delamination. Through constant temperature air drying in a dust-free and closed environment, the surface of the wheel hub can be ensured to be dry, clean, and free of impurities, providing a high-quality substrate surface for subsequent surface anodizing treatment. This effectively improves the bonding strength and molding uniformity of the composite protective coating, ensuring the overall protective performance and service life of the surface protective layer.

[0114] Comparative Example 2 (The dust-free enclosed air drying process was eliminated, and conventional natural air drying was adopted)

[0115] The preparation process for this comparative example is the same as that in Example 1, except that the dust-free, closed-loop air-drying step after water washing and purification is omitted and replaced with open-loop, room-temperature natural air-drying. All other steps, process parameters, and control standards are the same as in Example 1. The specific preparation steps are as follows:

[0116] S1) High magnesium alloy ratio: Same as in Example 1.

[0117] S2) Protective smelting and refining: Same as Example 1.

[0118] S3) Homogenization pretreatment of ingots: Same as in Example 1.

[0119] S4) Forging and turning composite forming: Same as Example 1.

[0120] S5) Gradient strengthening heat treatment: Same as in Example 1.

[0121] S6) Surface composite strengthening treatment

[0122] The heat-treated wheel blanks are subjected to micro-arc oxidation, pure water washing and purification, and hard anodizing in sequence. The water washing and purification process uses circulating pure water spray cleaning at a pressure of 0.3 MPa for 4 minutes. After water washing, the blanks are air-dried at room temperature for 8 minutes in an open, dust-free, and sealed environment. After air drying, micro-arc oxidation is performed at a voltage of 420V for 18 minutes. Once a 10μm thick ceramic protective layer is formed on the wheel surface, the processing is stopped, and the final wheel blank is obtained.

[0123] I. Comparative Example 2: Explanation of Finished Product Testing Methods

[0124] The sampling and testing environment, equipment, items, standards, and conditions of this comparative example are completely consistent with those of Example 1, ensuring that the test data are highly comparable and accurately verifying the impact of the dust-free, sealed drying process on the surface properties of the finished product.

[0125] II. Comparative Example 2: Test Data Table of Physicochemical Indicators of Finished Products

[0126] Test Project Test Standards Test conditions Test Results Matrix grain size GB / T 3246.1-2012 Same as Example 1 30μm, uniform grain structure with no coarse segregation tensile strength GB / T 228.1-2021 Same as Example 1 425MPa Yield strength GB / T 228.1-2021 Same as Example 1 362MPa Elongation after fracture GB / T 228.1-2021 Same as Example 1 14.0% matrix hardness GB / T 4340.1-2009 Same as Example 1 136HV Ceramic protective layer thickness GB / T 4957-2003 Same as Example 1 The coating is 10μm thick, with a small number of pinholes, and the adhesion is generally poor. neutral salt spray test GB / T 10125-2021 Same as Example 1 Minor coating peeling and pitting were observed in some areas. Wheel hub bending fatigue performance GB / T 5334-2014 Same as Example 1 1.15 million cycles without cracks or deformation Melt purity (inclusion level) GB / T 7999-2015 Same as Example 1 Inclusion level 0.5, excellent melt purity.

[0127] III. Test Results

[0128] Testing and verification showed that, in this comparative example, simply omitting the dust-free, enclosed drying process did not significantly reduce the mechanical properties of the wheel hub substrate. However, open-air drying easily leads to the adsorption of airborne dust and impurities on the wheel hub surface, causing a decrease in the adhesion of subsequent surface coatings and the appearance of micro-pinhole defects. Compared to Example 1, the corrosion resistance of the finished product was significantly reduced, the coating stability deteriorated, and peeling and flaking were prone to occur under long-term complex working conditions. This verifies the important role of the dust-free, enclosed drying process in improving the surface protection performance of the wheel hub and extending the service life of the coating.

[0129] In step S6, the micro-arc oxidation treatment voltage is 400–450V, and the treatment is continued for 15–20 minutes until a ceramic protective layer with a thickness of 8–12 μm is formed on the wheel hub surface. Specifically, a constant and suitable processing voltage ensures that the oxidation reaction proceeds smoothly and continuously, avoiding problems such as uneven oxide layer thickness, local breakdown, and loose coating caused by voltage fluctuations. The controllable processing time, combined with the film formation termination conditions, allows for precise control of the forming thickness of the ceramic protective layer, ensuring that the protective layer on the surface of each wheel hub is of uniform thickness and has a dense structure. The formed ceramic protective layer can significantly improve the hardness, wear resistance, and salt spray corrosion resistance of the wheel hub surface, effectively isolating the wheel hub substrate from external air, moisture, and corrosive media, and significantly improving the adaptability and long-term service life of the finished wheel hub under complex outdoor, corrosive, and heavy-load conditions.

[0130] Comparative Example 3 (Eliminating zone-specific spinning and adopting uniform spinning parameters)

[0131] The preparation process of this comparative example is completely consistent with that of Example 1, except that the differentiated spinning parameters for the rim and spoke zones are removed, and uniform spinning parameters are used throughout the entire process. All other procedures, process parameters, and control standards are the same as in Example 1. The specific preparation steps are as follows:

[0132] S1) High magnesium alloy ratio: Same as in Example 1.

[0133] S2) Protective smelting and refining: Same as Example 1.

[0134] S3) Homogenization pretreatment of ingots: Same as in Example 1.

[0135] S4) Forging and Spinning Composite Forming: The pre-treated wheel hub precast ingot is preheated to 395℃ and held for 2.5 hours to ensure uniform temperature throughout the ingot. A 7000-ton hydraulic forging press is used for segmented pressure-holding die forging. During die forging, the upper and lower dies are preheated simultaneously, and the die preheating temperature is controlled at 360℃. The pre-forging pressure is 50MPa and the holding pressure is 4s, while the final forging pressure is 70MPa and the holding pressure is 10s, resulting in a rough wheel hub blank. After the die forging process is completed, the process interval is controlled at 12 minutes, and the ambient temperature of the two processes is kept constant at 320℃. The spinning process uses uniform parameters throughout: feed rate 1.0mm / r, spinning speed 75r / min, and the spinning temperature is kept constant at 365℃ throughout the process, completing the wheel hub forming process.

[0136] S5) Gradient strengthening heat treatment: Same as in Example 1.

[0137] S6) Surface composite strengthening treatment: Same as in Example 1.

[0138] I. Comparative Example 3: Finished Product Testing Method Description

[0139] The sampling and testing environment, testing equipment, testing items, national testing standards, and testing conditions of this comparative example are completely consistent with those of Example 1, ensuring that the test data are highly comparable and verifying the effect of the zoned differentiated spinning process on improving the overall mechanical performance of the wheel hub.

[0140] II. Comparative Example 3: Test Data Table of Physicochemical Indicators of Finished Products

[0141] Test Project Test Standards Test conditions Test Results Matrix grain size GB / T 3246.1-2012 Same as Example 1 32μm, differences in the uniformity of the microstructure between the rim and the spokes. tensile strength GB / T 228.1-2021 Same as Example 1 410MPa Yield strength GB / T 228.1-2021 Same as Example 1 345MPa Elongation after fracture GB / T 228.1-2021 Same as Example 1 13.2% matrix hardness GB / T 4340.1-2009 Same as Example 1 131HV Ceramic protective layer thickness GB / T 4957-2003 Same as Example 1 10μm, uniform thickness without deviation neutral salt spray test GB / T 10125-2021 Same as Example 1 No rust, no coating peeling, no pitting corrosion Wheel hub bending fatigue performance GB / T 5334-2014 Same as Example 1 Localized fatigue lines appeared after 1.02 million cycles. Melt purity (inclusion level) GB / T 7999-2015 Same as Example 1 Inclusion level 0.5, excellent melt purity.

[0142] III. Test Results

[0143] Testing and verification revealed that this comparative example used uniform spinning parameters and failed to adapt differentiated forming processes to the different stress structures of the rim and spokes. This resulted in uneven metal flow in various parts of the wheel hub, localized stress concentration, and decreased microstructure density. Compared to Example 1, the overall mechanical properties and fatigue resistance of the finished product were significantly reduced, making it prone to localized fatigue damage under long-term heavy-load and bumpy conditions. This fully demonstrates that the differentiated spinning process of this invention can effectively adapt to the different stress requirements of the wheel hub structure, balance the overall stress distribution, and significantly improve the wheel hub's load-bearing capacity and service life.

[0144] As an additional note, the inclusion grade index in the aforementioned embodiments and comparative examples, i.e., the inclusion grade corresponding to the melt purity in each embodiment and comparative example, was strictly graded and determined according to the GB / T 7999-2015 standard "Direct Reading Emission Spectroscopy Analysis Method for Aluminum and Aluminum Alloys". It is a key indicator for evaluating the melting quality and matrix density of aluminum alloy melts. This grade adopts a numerical grading evaluation mechanism. The smaller the grade value, the lower the content of oxide inclusions, non-metallic impurities, micro-slag porosity, and segregation defects inside the alloy melt, and the better the melt purity and ingot microstructure density. Conversely, the larger the grade value, the more impurities and defects in the melt, and the easier it is for stress concentration sources to form inside the ingot, which will directly reduce the mechanical strength, fatigue resistance, and structural stability of the wheel hub. Based on the foregoing embodiments and comparative examples, the inclusion level of preferred embodiments 1 and 2 of the present invention can reach level 0.5 or below, which is a high purity melt standard and can ensure the excellent comprehensive service performance of the wheel hub. However, the inclusion level of comparative example 1, which cancels the gradient constant pressure filtration process, rises to level 1.5, and the melt impurity defects increase significantly. This is also one of the main reasons for the significant decline in the various performance characteristics of its finished product. This fully demonstrates that the inclusion level index is highly correlated with the quality and service life of the finished wheel hub.

[0145] Therefore, the test results of the aforementioned embodiments and comparative examples show that this application, by optimizing the entire process system of alloy smelting and refining, melt filtration, forging and shaping, heat treatment, and surface strengthening, can stably produce high-magnesium aluminum alloy wheel hubs with dense structure, excellent mechanical properties, and outstanding corrosion resistance and fatigue resistance. Among them, Examples 1 and 2, as preferred process schemes of this invention, have significantly better overall performance than the comparative examples. Moreover, the two preferred embodiments can be adapted to heavy-duty special working conditions and conventional mass production working conditions, respectively, with a wide range of working condition adaptability and strong mass production practicality. The process difference of only replacing the refining agent allows the two preferred embodiments to form a performance gradient, which can take into account both high-end heavy-duty quality and conventional mass production economy. In each comparative example: the gradient pore size constant pressure filtration process can effectively improve the purity of the melt and refine the grain structure, fundamentally improving the mechanical properties and structural stability of the wheel hub substrate; the dust-free closed air drying process can effectively avoid defects caused by the adsorption of impurities on the wheel hub surface, ensuring the density and adhesion of the composite protective coating, and significantly improving the corrosion resistance and service life of the product; the zoned differentiated spinning process can accurately adapt to the stress characteristics of different wheel hub structures, balance the internal stress distribution, and solve the problems of uneven structure, stress concentration, and insufficient fatigue life caused by uniform spinning forming.

[0146] In summary, this invention effectively solves the technical defects of traditional high-magnesium aluminum alloy wheel hubs, such as easy segregation, high impurity content, insufficient mechanical properties, poor stability of protective layer, and short fatigue life, through the synergistic cooperation of various processes. The prepared product has excellent comprehensive performance and high quality stability, which can meet the stringent use requirements of heavy-duty special vehicles, and can also be adapted to the mass production of ordinary passenger cars and light-duty commercial vehicles, thus possessing extremely high engineering application value and market promotion prospects.

[0147] According to another aspect of this application, a high-magnesium, lightweight, high-strength, high-performance heavy-duty aluminum alloy wheel hub is also provided, which is prepared by the aforementioned manufacturing method of the high-magnesium, lightweight, high-strength, high-performance heavy-duty aluminum alloy wheel hub.

[0148] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing a high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub, characterized in that, Includes the following steps: S1) High magnesium alloy ratio The alloy raw materials are configured according to the following mass percentages: magnesium content 7.0%–9.0%, silicon 0.2%–0.4%, copper 0.1%–0.3%, manganese 0.3%–0.6%, titanium 0.08%–0.15%, and the balance being industrial pure aluminum. S2) Protective smelting and refining The industrial pure aluminum prepared in step S1 is put into a melting furnace and heated to 720-750℃ until it is completely melted. When the furnace temperature is kept constant at 750℃, silicon, copper, manganese and titanium components are added. After holding at this temperature for 5-8 minutes, the temperature is lowered to 730℃, and then magnesium components are added. Argon gas is continuously introduced throughout the process for protection. After melting, a refining agent is added and the mixture is rotary refined for 10-15 minutes. After standing for 20-30 minutes, the melt is filtered as a whole using a 200-250 mesh ceramic filter plate to obtain aluminum alloy melt. S3) Homogenization Pretreatment of Ingots The melt obtained in step S2 is cast into a precast wheel hub ingot, with the casting temperature controlled at 700-720℃. The ingot is then sent to a homogenizing heat treatment furnace, where it is heated in stages with gradient heating and holding. First, the temperature is raised to 420-440℃ and held for 4-6 hours, then raised to 480-495℃ and held for 8-10 hours. Subsequently, the furnace body is cooled to 350-360℃ and held isothermally for 2 hours. After homogenization, the ingot is cooled to room temperature using a water mist cooling method. S4) Forging and Rotation Composite Forming The pre-treated wheel hub precast ingots are preheated to 380–410℃ and held for 2–3 hours to ensure uniform temperature. A 6000–8000 ton hydraulic forging press is used for segmented pressure forging, with a pre-forging pressure of 45–55 MPa and a holding pressure of 3–5 seconds, and a final forging pressure of 65–75 MPa and a holding pressure of 8–12 seconds to form the wheel hub rough blank. A CNC spinning machine is used for zoned differential speed spinning, with a constant feed rate of 1.0–1.2 mm / r and a spinning speed of 80–100 r / min for the rim section, and a constant feed rate of 0.8–1.0 mm / r and a spinning speed of 50–70 r / min for the spoke section, maintaining a constant spinning temperature of 350–380℃ throughout the process. S5) Gradient strengthening heat treatment The formed wheel hub blank is first subjected to low-temperature stress relief pretreatment, heated to 100-120℃ and held for 1-2 hours; then subjected to solution treatment, heated to 475-485℃ and held for 2.5-3.5 hours, followed by rapid water quenching; finally subjected to two-stage aging treatment, with the first stage aging at 120-140℃ and held for 3-4 hours, and the second stage aging at 170-190℃ and held for 5-6 hours. S6) Surface composite strengthening treatment The heat-treated wheel blanks are subjected to micro-arc oxidation, pure water washing and purification, and hard anodizing in sequence. The water washing and purification process uses circulating pure water spray cleaning with a spray pressure of 0.2-0.4 MPa and a cleaning time of 3-5 minutes to generate a composite protective coating on the wheel surface, resulting in a finished high-magnesium, lightweight, heavy-duty aluminum alloy wheel.

2. The manufacturing method of the high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub according to claim 1, characterized in that, In step S2, the refining agent is an aluminum-titanium-boron composite refining agent or an aluminum-zirconium-carbon composite refining agent. Under conventional preparation conditions, the aluminum-titanium-boron composite refining agent is selected, while under high-purity preparation conditions, the aluminum-zirconium-carbon composite refining agent is selected. The conventional preparation conditions refer to the mass production conditions that meet the conventional mechanical properties and purity requirements of wheel hubs for ordinary passenger cars and light commercial vehicles, while the high purity preparation conditions refer to the high-end preparation conditions that meet the requirements of ultra-high density and ultra-low impurity content for wheel hubs for heavy-duty vehicles and special-operation vehicles. The amount of refining agent added is 0.15% to 0.25% of the total mass of the alloy melt, and the argon gas flow rate is 8 to 12 L / min.

3. The manufacturing method of the high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub according to claim 1, characterized in that, In step S2, the ceramic filter plate is provided with a decreasing aperture structure along the melt flow direction, with the aperture at the melt inlet end being larger than the aperture at the melt outlet end, and the melt filtration pressure is maintained at 0.08 to 0.12 MPa.

4. The manufacturing method of the high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub according to claim 1, characterized in that, In step S3, the cooling rate of the water mist slow cooling is controlled at 15-25℃ / min, and the grain size inside the ingot is uniformly controlled at 20-40μm after cooling.

5. The manufacturing method of the high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub according to claim 1, characterized in that, In step S4, the upper and lower dies are preheated simultaneously during die forging, and the die preheating temperature is 350-370℃.

6. The manufacturing method of the high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub according to claim 1, characterized in that, In step S4, the interval between the completion of the die forging process and the start of the spinning process shall not exceed 15 minutes, and the operating environment temperature of the two processes shall be kept constant at 300-350℃.

7. The manufacturing method of the high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub according to claim 1, characterized in that, In step S5, the water quenching cooling rate is ≥80℃ / s, and the water temperature after water quenching is ≤40℃.

8. The manufacturing method of the high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub according to claim 1, characterized in that, In step S6, after the water washing and purification process is completed and before the hard anodizing process is started, a 5-10 minute room temperature air drying and settling process is added. The air drying operation adopts a dust-free and closed working environment.

9. The manufacturing method of the high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub according to claim 1, characterized in that, In step S6, the micro-arc oxidation treatment voltage is 400-450V, and the treatment is continued for 15-20 minutes. The processing is stopped after a ceramic protective layer with a thickness of 8-12μm is formed on the surface of the wheel hub.

10. A high-magnesium, lightweight, high-strength, heavy-duty aluminum alloy wheel hub, characterized in that, The high-magnesium, lightweight, high-performance, heavy-duty aluminum alloy wheel hub is manufactured by any of the manufacturing methods described in claims 1-9.

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