Wheel rim production process and casting wheel rim based on tilt casting

Abstract

This invention discloses a wheel rim production process based on tilt casting. The process includes: melting A356.2 aluminum alloy, adjusting the aluminum liquid composition to the range of Fe≤0.19%, Mg:0.30%-0.45%, and Si:6.5%-7.5%, and refining and metering; the casting machine drives the mold to tilt, and when the tilt angle reaches 40-50°, the aluminum alloy liquid is poured into the ladle of the metal mold to begin pouring, with the initial pouring at a first angular velocity ω1; when the tilt angle is less than 30°, the main filling is carried out at a second angular velocity ω2 greater than ω1; when the tilt angle is less than 10°, the final deceleration filling is carried out at a third triangular velocity ω3 less than ω2; after the mold is tilted back to horizontal, the filling is completed, the tilting casting machine is locked, and then the cooling system is started, and the cooling process is controlled according to the temperature data inside the mold; the casting is then subjected to sequential mold opening, part removal, and heat treatment. This solution realizes the casting production process of wheel rim products, enabling the casting to have a tensile strength exceeding 280MPa and an elongation after fracture exceeding 8%, thereby improving the overall performance of the wheel rim.

Description

Technical Field

[0001] This invention relates to the field of wheel rim manufacturing technology, specifically to a wheel rim manufacturing process based on inclined casting and a cast wheel rim. Background Technology

[0002] Inclined casting is a process that guides the smooth filling of molten metal by controlling the tilt angle of the mold. Its core principle is to utilize gravity to allow the molten metal to flow slowly along the inner wall of the mold, thereby reducing turbulence, splashing, and gas entrapment. In this process, the mold is typically initially set to an inclined position. As the molten metal is poured in, the mold angle is adjusted synchronously until it becomes vertical, allowing the liquid level to rise smoothly and facilitating the upward flotation and removal of gas and inclusions. This method is particularly suitable for alloys that are prone to oxidation or gas absorption, such as bronze alloys, and can improve the internal quality of the casting.

[0003] Application announcement number CN120886008A discloses a manufacturing method for a lightweight, heat-free alloy automobile wheel hub. According to its specification and accompanying drawings, the method involves casting a lightweight alloy into a cylindrical shape using gravity tilting casting; then spinning the cylinder into the desired wheel rim using a spinning machine; performing heat treatment followed by machining to form a semi-finished wheel rim required before wheel welding; simultaneously, using vibration pressure casting to cast spokes of various shapes, followed by machining; and finally, welding the wheel rim and spokes together using friction stir welding or inertial friction welding to form a wheel hub blank.

[0004] Whether it is gravity casting or low-pressure casting, during the pouring process: 1. The impact of molten aluminum on the mold cavity is relatively large, and the liquid flow front is prone to encapsulating gas and oxide scale, which eventually forms defects such as porosity and slag inclusions inside the wheel rim, affecting the fatigue strength and safety of the wheel rim.

[0005] 2. Wheel rims made using profile extrusion and spot welding possess certain mechanical properties and strength. However, their disadvantages include high equipment investment costs, moderate production efficiency, and slightly inferior mechanical properties at the welded joint compared to other parts of the rim. Furthermore, due to current technological limitations, it is currently impossible to produce products with a width greater than 2.5 inches and a diameter less than 16 inches. This is especially true for models of wire-spoke motorcycle wheels with ribs on the inner side, as the presence of these ribs prevents the profile from being rolled into a round shape, thus making the profile rolling, extrusion, and spot welding process unsuitable. Summary of the Invention

[0006] This invention addresses the aforementioned problems in wheel rim manufacturing processes by proposing a wheel rim manufacturing process and casting wheel rims based on inclined casting, thereby achieving excellent and stable comprehensive mechanical properties in wheel rim castings, including tensile strength exceeding 280 MPa and elongation after fracture exceeding 8%.

[0007] Therefore, the first aspect of the present invention is to propose a wheel rim production process based on inclined casting.

[0008] A second aspect of the invention is to provide a cast wheel rim.

[0009] In view of this, the first aspect of the present invention is achieved by the following technical solution: a wheel rim manufacturing process based on inclined casting, comprising the following steps: S1: Melt A356.2 aluminum alloy, adjust the aluminum liquid composition to the range of Fe≤0.19%, Mg: 0.30%~0.45%, Si: 6.5%~7.5%, and perform refining and quantitative setting of aluminum liquid pouring; S2: After the mold is closed, place a filter screen at the mold pouring port, drive the mold to tilt so that the ladle moves downward. When the angle between the upper surface of the mold and the horizontal plane reaches (45±5)°, the upper end of the ladle is parallel to the ground. Start injecting a fixed amount of molten aluminum into the ladle from the quantitative furnace. Drive the mold and ladle to tilt back and start pouring, and start pouring with the first angular velocity ω1. When the angle between the upper surface of the mold and the horizontal plane is less than (30±5)°, pour the main body of the casting with the second angular velocity ω2, which is greater than ω1. When the angle between the upper surface of the mold and the horizontal plane is less than (10±3)°, decelerate the filling with the third triangular velocity ω3, which is less than ω2. The last bit of molten aluminum and oxide scale remain in the ladle to cool. S3: After tilting the mold upwards to a horizontal position, the filling process is completed. Then, the flipping casting machine is locked, and the cooling system is started. The cooling process is then adjusted according to the real-time temperature data of the thermocouples inside the mold. S4: Remove the aluminum oxide scale from the ladle, and perform the following steps on the casting: mold opening, part removal, air cleaning of the mold cavity, mold closing, tilting pouring, casting cooling, removal of the pouring riser, X-ray inspection, heat treatment, and machining.

[0010] Preferably, step S1 specifically includes: S11: The refining is rotary powder spraying refining: at (740±10)℃, an inert gas is used to carry the refining agent and spray it into the depth of the aluminum liquid, and the powder spraying time is not less than 3 minutes; S12: After refining, aluminum-strontium alloy is added to the melt every half hour for modification treatment, and magnesium blocks are added every hour for fine-tuning of the composition; S13: Strictly control the temperature of the molten aluminum within the range of (700±20)℃; S14: The quantitative pouring of aluminum liquid is accomplished by the electromagnetic pump of the quantitative furnace and the Coriolis mass flow meter, and the quantitative accuracy is controlled within ±0.3%. Preferably, step S2 specifically includes: S21: Before performing tilting filling, preheat the mold to 180℃~250℃ and spray a double-layer coating on the mold cavity: the first layer is a silica sol-based coating to form a dense underlayer of about 0.1mm thick, and the second layer is a coating containing nano-graphite to form a lubricating functional layer of about 0.3mm thick. S22: Before mold closing and pouring, use dry compressed air to thoroughly blow away impurities in the cavity in the order of mold core first and then slide rail. S23: The first angular velocity ω1 is (5.0±1.0)° / s, the second angular velocity ω2 is (7.0±1.0)° / s, and the third angular velocity ω3 is (5.0±1.0)° / s; S24: Before pouring, place a high-temperature resistant filter screen at the pouring port and use a preheated ladle to gently skim off the slag on the surface of the molten aluminum in the ladle.

[0011] Preferably, in step S23: The initial pouring was carried out at an angular velocity of (5.0±1.0)° / s, which was intended to allow the molten aluminum to quickly establish a stable molten metal pad at the bottom of the cavity; The casting body is poured and filled with an angular velocity of (7.0±1.0)° / s, so that the flow of molten metal can quickly fill the entire wheel rim cavity; The end-stage deceleration filling is performed at an angular velocity of (5.0±1.0)° / s to reduce the amount of oxide scale, particulate impurities and gas that are flushed into the casting body by the molten aluminum, and to facilitate the rise of oxide scale, particulate impurities and gas to the riser.

[0012] Preferably, step S3 specifically includes: S31: After filling is complete, stop and lock the mold in a horizontal position; S32: Activate the partitioned cooling system, which includes several first cooling circuits evenly distributed in a circle at the bottom of the lower mold, with the bottom of the cooling holes of the first cooling circuits opening inside the lower end of the wheel rim cavity; several second cooling circuits evenly distributed in a circle at the outside of each side mold, with the bottom of the cooling holes of the second cooling circuits opening below the wheel rim at the upper end of the corresponding wheel rim cavity of the side mold; and several third cooling circuits evenly distributed in a circle at the top of the upper mold, with the bottom of the cooling holes of the third cooling circuits opening inside the upper end of the wheel rim cavity of the upper mold. S33: Based on the real-time temperature data, dynamically adjust the medium flow rate and time of each cooling circuit to force the casting to form a solidification sequence from the lower end of the wheel rim to the upper end of the wheel rim; S34: When the temperature at the center of the casting drops to 400℃~450℃, cooling is considered complete.

[0013] Preferably, step S4 specifically includes: S41: The sequential mold opening is performed in the following order: After cleaning the oxide scale in the ladle, the mold is opened: First, the lower mold and side molds, together with the casting, are moved down to separate the upper mold from the casting. The upper mold locking mechanism is opened, the upper mold is flipped upward to open, all side molds are opened simultaneously, the lower mold ejection mechanism is activated to eject the casting, and the robot arm grabs the casting and transfers it to the cooling area; Mold closing: Using dry compressed air, impurities in the cavity are thoroughly blown away in the order of mold core first and then slide rail. The ejector rod of the lower mold ejection mechanism is reset first, all side molds are closed simultaneously, the upper mold is flipped downward to the position, the upper mold locking mechanism is closed, the lower mold and side molds rise to close with the upper mold, the tilting flipping mechanism flips the mold downward, a high-temperature resistant filter screen is placed at the funnel of the gating system, a metered amount of aluminum liquid is injected into the ladle by the metered furnace, the tilting casting machine is reset upward and the aluminum liquid is poured and filled, and the casting solidifies and cools sequentially; the mold opening and part removal are repeated, and after the casting cools, the gating riser is removed, and the internal structure is inspected with an X-ray flaw detector; S42: The heat treatment is T6 heat treatment, specifically: solution treatment at (535±5)℃ for (6±0.5) hours, water quenching at (80±10)℃, aging at (145±5)℃ for (5±0.5) hours, followed by air cooling. S43: Periodically cut sample bars from three evenly distributed points on the upper and lower parts of the casting rim and perform mechanical property tests on a material testing machine; S44: Perform full-size machining and turning on the casting, and drill valve holes and wire holes.

[0014] Preferably, before performing step S2, the method further includes: preheating the mold to 180°C to 250°C, and spraying a double-layer coating on the mold cavity, wherein the first layer is a silica sol-based coating to form a dense underlayer, and the second layer is a coating containing nano-graphite to form a lubricating functional layer.

[0015] According to a second aspect of the present invention, a cast wheel rim is provided, which is manufactured using the wheel rim production process based on inclined casting provided by any of the above-described technical solutions.

[0016] The cast wheel rim provided by the present invention is manufactured using the wheel rim production process based on inclined casting provided by any of the above technical solutions. Therefore, it has all the beneficial effects of the wheel rim production process based on inclined casting, which will not be repeated here.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. Based on the structural characteristics of the wheel rim casting mold cavity, multi-segment tumbling speeds of ω1=(5.0±1.0)° / s, ω2=(7.0±1.0)° / s, and ω3=(5.0±1.0)° / s were cleverly set. This is not a simple variation of uniform tumbling, but rather based on a profound understanding of the flow, heat transfer, and venting patterns of molten metal in the complex cavity composed of the upper mold, lower mold, and side mold. ω1 quickly establishes a molten metal pad, ω2 ensures rapid filling of the entire wheel rim cavity, and ω3 helps reduce the influx of oxide scale, particulate impurities, and gas into the casting body by the molten aluminum, facilitating the riser of oxide scale, particulate impurities, and gas, and allowing the gas to be smoothly discharged from the riser and vent plug. This combination of parameters effectively suppresses defects such as gas entrapment, oxide inclusions, and cold shuts.

[0018] 2. The PLC program achieves precise programmed control over multi-segment adjustments to the tumbling speed, preset and verification of cooling water flow and pressure, and the automatic execution of the mold opening sequence: lower mold, upper mold, side mold, and ejection mechanism. The linkage reliability design of the ejection mechanism (mold release rod, push plate, ejector push plate, ejector plate, and ejector rod), combined with the sequential mold opening logic, avoids damage to the high-temperature casting. After filling, the mold stops in a horizontal position. This specific angle places the gating and riser system above the thermal center of the casting, cleverly utilizing gravity for directional shrinkage compensation. Simultaneously, based on real-time data from multiple thermocouples embedded in key parts of the upper mold, lower mold, and side mold, the system dynamically adjusts and forces the solidification direction from bottom to top of the rim, ensuring a continuous supply of liquid metal during solidification shrinkage, thereby eliminating internal shrinkage porosity, significantly improving casting density, and achieving a high tensile strength >280MPa.

[0019] 3. From deep refining with a powder sprayer, online spectral analysis and fine-tuning (controlling Fe≤0.19%, etc.), to pollution-free quantitative transfer via an electromagnetic induction quantitative holding furnace and electromagnetic pump, the entire process ensures the cleanliness and precise composition of the alloy liquid, providing an excellent initial microstructure for heat treatment. The solution treatment (535±5℃ / 6±0.5h), quenching (80±10℃ water), and aging (145±5℃ / 5±0.5h) parameters are optimized processes that match the composition of the A356.2 alloy and the dense microstructure obtained by casting, fully dissolving the strengthening phase and subsequently precipitating it, further optimizing the material matrix microstructure. Attached Figure Description

[0020] Figure 1 This is a perspective view of the mold of the present invention; Figure 2 This is a flowchart of the present invention; Figure 3 This is a perspective view of the final product of the wheel rim of the present invention; Figure 4 This is a perspective view of the initial blank of the wheel rim according to the present invention; Figure 5 This is a schematic diagram of the mold of the present invention after it has been installed on the tilting casting machine.

[0021] The markings in the diagram are: 1. Upper mold; 2. Ladle; 3. Riser plate; 4. Sprue insert; 6. Small guide sleeve; 9. Lower mold; 12. Side mold connecting plate; 13. Machine base connecting plate; 14. Side mold connector; 15. Water pipe insert; 16. Hydraulic cylinder connector; 17. Small guide post; 18. Ejector rod; 19. Water pipe; 20. Side mold; 21. Stroke guide post; 22. Mold release rod; 23. Lower mold base; 24. Push plate; 25. Ejector rod push plate; 26. Ejector rod plate. Detailed Implementation

[0022] The present invention will be further described below with reference to the embodiments illustrated in the accompanying drawings: This embodiment presents a complete production system integrating alloy smelting, tilting casting, and intelligent control. The system mainly includes: a mold heating and temperature control system; and an alloy smelting and refining unit comprising a smelting furnace, refining chamber, powder spraying machine, and electromagnetic induction quantitative holding furnace, equipped with online composition analysis and closed-loop temperature control functions.

[0023] Inclined casting and molding unit: This is an intelligent tilting casting machine capable of precise rotation, with its rotation speed adjustable in multiple segments within the range of 4-9° / s via a PLC program. This unit also includes wheel rim casting molds mounted on it. Quality inspection and post-processing unit: This unit includes a spectrometer, infrared thermometer, X-ray flaw detection equipment, robotic part removal, heat treatment equipment, CNC turning machine, valve hole drilling machine, and wire hole drilling machine.

[0024] Please refer to the reference. Figure 1 As shown, the mold system includes an upper mold 1, a side mold 20, and a lower mold 9, which together form the cavity of the wheel rim after being closed. The non-exterior surface of the cavity of the upper mold 1 is provided with micro-turbulence ribs for guiding the flow of molten metal. At least one side mold 20 is movably disposed on the side of the upper mold 1 and the lower mold 9 for forming the radial profile of the wheel rim. The mold integrates a point cooling and slow cooling subsystem with independent regional control.

[0025] The mold body is made of high-grade hot work die steel, which is vacuum quenched and tempered multiple times to achieve a hardness of approximately 48-50 HRC, ensuring strength and wear resistance at high temperatures. All mold cavities and runner surfaces are subjected to five-axis high-speed precision milling, precision turning, and hand polishing, with a final surface roughness Ra≤0.4μm, ensuring a smooth casting surface and facilitating demolding.

[0026] The wheel rim casting mold (including upper mold 1, lower mold 9, and side mold 20) is installed on the intelligent tilting casting machine via the machine base connecting plate 13. After assembly, it is necessary to manually check whether the actions of all mechanisms such as closing the side mold, opening the upper mold, and ejection are smooth, confirm that the precision guide pair composed of the stroke guide post 21, the small guide post 17, and the small guide sleeve 6 is working properly, and confirm that the linkage ejection mechanism composed of the mold release rod 22, the push plate 24, the ejector push plate 25, the ejector plate 26, and the ejector rod 18 is complete and reliable.

[0027] Please continue to refer to this. Figure 2 , Figure 3 and Figure 4 This embodiment describes a wheel rim manufacturing process based on inclined casting, including the following steps: S1: Clean smelting of alloys, refined composition adjustment and quantitative casting preparation.

[0028] S11: Melting preparation, online refining and periodic composition fine-tuning.

[0029] S111: Prepare sufficient quantities of slag remover, powder refining agent, small magnesium blocks, and aluminum-strontium alloy blocks according to the production plan. At the same time, ensure that slag removal tools are preheated and ready for use.

[0030] S112: Melt A356.2 aluminum ingots in a melting furnace, transfer the molten aluminum liquid to a holding furnace for refining, add a covering agent to the surface of the melt, and at the same time purge and protect it with inert gas from the bottom of the furnace.

[0031] S113: At approximately 740°C, start the powder spraying machine, insert the preheated powder spraying pipe into the molten aluminum, and use inert gas to carry the powder refining agent into the depth of the molten pool for deep degassing and slag removal.

[0032] In step S113, the powder spraying process standard is as follows: powder is sprayed once each time aluminum alloy molten liquid is introduced from outside the holding furnace, and / or powder is sprayed once every 2 hours. The amount of refining agent used is 2.5KG per 10 tons of aluminum liquid in the melting furnace, and the powder spraying time is ≥3 minutes.

[0033] S114: After refining, the surface of the molten aluminum in the holding furnace should meet the quality standard of having no visible slag. After standing for 15 minutes, start pouring the molten aluminum from the holding furnace into the preheated transfer bag.

[0034] S115: Add aluminum-strontium alloy and small magnesium blocks once for each batch of transferred molten aluminum to achieve online fine-tuning and modification of alloy elements.

[0035] S12: Composition spectral analysis, precise temperature control, and quantitative transfer of molten aluminum into a quantitative furnace.

[0036] S121: Every two hours, take a sample from the water inlet of the quantitative furnace using a preheated hydrogen measuring cup. The sample volume should be 1 / 2 to 2 / 3 of the volume of the measuring cup, and clearly label it with a unique sample number for the furnace area. Send the sample to the spectrometer for chemical composition analysis.

[0037] S122: Furnace operators must promptly check the spectral analysis results. The aluminum liquid composition must meet the following process standards: Fe≤0.19%, 0.30%≤Mg≤0.45%, 6.5%≤Si≤7.5%, 0.08%≤Ti≤0.20%, 0.006%≤Sr≤0.015%, Cu, Mn, Zn≤0.1%, Ni, Sn, Pb≤0.05%, Ca≤0.006%, other individual elements≤0.05%, and the sum of other elements≤0.15%. If any composition is unqualified, corresponding adjustments must be made.

[0038] S123: Operators must hold a temperature measuring rod to measure the actual temperature and strictly and stably control the temperature of the molten aluminum at the water intake within 680℃~720℃.

[0039] S124: Pour the slag remover into the refining chamber of the holding furnace, stir it evenly to cover the surface of the molten aluminum, and record all process parameters such as the completion of the powder spraying and slag removal process and the amount of aluminum-strontium alloy and small magnesium blocks added.

[0040] S125: Transfers molten aluminum with qualified composition and temperature into an electromagnetic induction quantitative holding furnace. The molten aluminum is transported without contact by an electromagnetic pump at the bottom of the furnace, and the quantitative accuracy is ensured by a Coriolis mass flow meter, with the error controlled within ±0.3%.

[0041] S126: Molten aluminum is transported through a preheated ceramic riser pipe and kept at 700℃~720℃ in the furnace for later use.

[0042] S2: Systematic preparation of inclined casting molds, automatic mold closing and multi-stage collaborative pouring.

[0043] S21: Mold assembly, preheating and functional coating application.

[0044] S211: Mold assembly and structural inspection.

[0045] S212: Start the mold heating system to preheat the entire mold to the process range of 180℃~250℃ and maintain a uniform and stable temperature.

[0046] In step S212, the heated components are the upper mold 1, the lower mold 9, the side mold 20, and other components contained therein.

[0047] S213: Using a hybrid spray gun, spray at a distance of approximately 250mm from the cavity surface: the first layer is a high-viscosity silica sol-based coating, with a pressure of approximately 0.5MPa, forming a dense underlayer of approximately 0.1mm thickness.

[0048] In step S213, the main function of the high-viscosity silica sol-based coating is to isolate the high-temperature aluminum liquid from direct contact with the mold steel substrate, significantly reducing the risk of corrosion.

[0049] S214: Continue spraying the second layer at a distance of about 250mm from the cavity surface: spray a water-based coating containing nano-graphite flakes and boron nitride at a pressure of about 0.5MPa to form a surface functional layer of about 0.3mm thickness.

[0050] In step S214, this facilitates subsequent demolding of the casting and ensures the appearance quality of the wheel rim.

[0051] S22: Pre-treatment of the gating system, configuration of the cooling system and final cleaning of the cavity.

[0052] S221: Thoroughly clean all aluminum slag in the quantitative furnace flow channel and spray BS-407S refractory coating onto its working surface.

[0053] S222: Before use, ladle 2 should be cleaned by sandblasting with iron sand, and then preheated simultaneously during the mold heating stage.

[0054] S223: After preheating, first spray the inner and outer walls of the ladle 2 with NC-10B coating, and then spray a layer of BS-407S coating on its inner working surface to form double protection.

[0055] S224: After the mold is installed, install the pouring ladle 2. It must be ensured that the pouring ladle 2 fits tightly with the stop block above the mold gate, with no visible gaps.

[0056] In step S224, if there is a gap between the ladle 2 and the stop above the mold gate, it is necessary to use tools such as an angle grinder to grind it smooth to ensure a tight fit, which is crucial to prevent aluminum liquid from splashing during pouring.

[0057] S225: Verify that the parameters such as cooling water flow rate, pressure, and rotation speed of each section are completely consistent with the specifications of the current product.

[0058] S226: Check all cooling water pipes for leaks, blockages, or missing parts, and ensure the water intake is appropriate.

[0059] S227: Install the corresponding water-cooling pipes and air-cooling pipes for each part according to the thermal distribution diagram of the mold.

[0060] S228: After each mold change, the position of the quantitative furnace outlet trough must be adjusted to ensure that the ladle 2 will not collide with the quantitative furnace outlet trough when the machine is tilted and flipped in the subsequent operation, so as to prevent equipment damage and aluminum liquid splashing.

[0061] S229: Before mold closing and pouring, open the mold and use dry compressed air to thoroughly blow away impurities from the upper and lower mold cavities, mold shank, and all slider tracks in sequence.

[0062] In step S229, the following order and standards must be followed during cleaning: First, blow away impurities from the mold cores and shanks of the upper mold 1 and lower mold 9; then, focus on blowing away impurities, especially aluminum shavings, from the slides below the sliders of each side mold 20, which must be thoroughly removed to prevent the sliders from becoming stuck and failing to close the mold. At the same time, check whether all ejector pins 18 have fully retracted into their positions.

[0063] S23: Fully automatic mold closing, tilting and flipping, and multi-stage collaborative filling.

[0064] S231: Press the automatic mold closing button, and the equipment will automatically execute the preset program: the equipment will close the side mold 20 in sequence, flip the upper mold 1 downward to close the mold, lock the upper mold 1, close the upper and lower molds, and tilt and flip the whole to make the pouring ladle move downward until the angle between the upper surface of the mold and the horizontal plane is within the range of (45±5)°.

[0065] In step S231, the operator must observe the mold closing process and immediately press the emergency stop button if any abnormality is found.

[0066] S232: Final inspection and filter placement before pouring. After the mold is tilted and flipped into place, the operation is paused, and the operator checks whether the mold closing and ladle alignment are normal.

[0067] S233: After confirming that everything is correct, place a high-temperature resistant filter screen at the funnel of the casting system to filter out any tiny inclusions that may be present in the molten aluminum.

[0068] S234: Start the metering furnace and inject precisely measured molten aluminum into ladle 2.

[0069] S235: After the molten aluminum is poured into ladle 2 and before pouring begins, the operator uses a preheated ladle to gently skim off the scum on the surface of the molten aluminum from the inlet of ladle 2 (away from the mold).

[0070] In step S235, the skimming process must be gentle, treating only the surface layer, and there is no need to stir the molten aluminum to avoid trapping gas within the aluminum. At the same time, any aluminum shavings that may adhere to the inner wall of ladle 2 should be cleaned.

[0071] S236: Multi-stage variable speed tilting filling process.

[0072] S2361: When the angle between the upper surface of the mold and the horizontal plane reaches (45±5)°, the quantitative furnace is started, and molten aluminum is injected into ladle 2 at a constant flow rate of about 2.0 kg / s. After all the quantitative molten aluminum is injected into ladle 2, the mold flips back with a first angular velocity ω1 = (5.0±1.0)° / s, and the molten aluminum flows from the ladle into the pouring gate and to the bottom of the mold cavity.

[0073] In step S2361, the higher flipping speed is intended to allow the molten aluminum to quickly fill the runner and flow into the bottom of the wheel rim cavity, quickly establishing a stable molten metal pad, thereby reducing premature cooling of the molten metal at the bottom of the cavity and laying the foundation for smooth filling in the subsequent process.

[0074] S2362: When the angle between the upper surface of the mold and the horizontal plane is less than (30±5)°, the molten aluminum begins to fill the main body of the casting, i.e. the wheel rim cavity area. The mold turning speed is adjusted to the second angular velocity ω2=(7.0±1.0)° / s. This stage lasts for about 3 seconds.

[0075] In step S2362, at this speed, the continuously flowing molten metal effectively compensates for the heat loss of the wheel rim cavity surface, avoiding excessive heat loss due to the large heat dissipation area in this area, thereby ensuring that the wheel rim cavity is completely filled and has a clear outline.

[0076] S2363: When the angle between the upper surface of the mold and the horizontal plane is less than (10±3)°, the filling process enters the final stage. The mold turning speed is reduced to the third angular velocity ω3=(5.0±1.0)° / s, and the last bit of molten aluminum and oxide scale remain in the ladle to cool.

[0077] In step S2363, during this low-speed flipping stage, the leading edge of the molten metal can push the gas and oxide film at the top of the cavity at an extremely stable speed, allowing them sufficient time to be discharged through the vent plug and riser overflow groove, rather than being drawn into the casting. The oxide scale in the ladle will also not be injected into the casting, which is the key to obtaining a dense, non-porous casting.

[0078] S2364: The molten metal completely fills the cavity and riser, and the mold stops precisely in a horizontal position.

[0079] S237: The rotation and return speed of the machine should be adjusted according to the temperature of the molten aluminum, the temperature of the mold, and the size of the mold gate. The general adjustment range is (4~9)° / s. The specific optimal value is based on the process card of each product model and can be achieved by modifying the PLC parameters.

[0080] S3: Optimized feeding posture adjustment and directional sequential solidification under temperature field monitoring.

[0081] S31: Post-filling stability and gravity-fed posture optimization.

[0082] S311: After the molten aluminum completely fills the cavity, the mold is locked and held in a horizontal position, which initially stabilizes the turbulent molten metal and allows some residual gas to float to the overflow system.

[0083] In step S311, the mold orientation during the solidification stage is set to a horizontal position. This angle places the gating and riser system, especially the main runner (which enters from a block riser), above the overall geometric center (and thermal center) of the casting. In this orientation, gravity and the hydrostatic pressure of the molten metal work together to compensate for the shrinkage of the preferentially cooled parts of the wheel rim during solidification, significantly reducing or even eliminating internal shrinkage defects in the casting.

[0084] S32: Closed-loop control of the intelligent cooling system startup and solidification process.

[0085] S321: Introduce cooling medium into the spot cooling subsystem and slow cooling subsystem of the mold.

[0086] In step S321, the cooling medium of the spot cooling subsystem is water, and the cooling medium of the slow cooling subsystem is compressed air. The spot cooling subsystem is a spot cooling rod with a double-layer water channel design. The bottom of the cooling hole is about 15mm away from the surface of the cooling cavity. Deionized water at about 25°C is introduced at a flow rate of about 3.0m / s for high-intensity cooling. The zoned cooling system includes several first cooling circuits evenly distributed in a circle at the bottom of the lower mold 9. The bottom of the cooling holes of the first cooling circuits is opened on the inner side of the lower end of the wheel rim cavity. Several second cooling circuits are arranged on the outer side of each side mold 20. The bottom of the cooling holes of the second cooling circuits is opened below the rim of the corresponding upper end of the wheel rim cavity of the side mold 20. Several third cooling circuits are evenly distributed in a circle at the top of the upper mold 1. The bottom of the cooling holes of the third cooling circuits is opened on the inner side of the upper end of the wheel rim cavity of the upper mold 1. Natural cooling is used for the rim area of ​​the side mold 20 to reduce the cooling intensity of this area.

[0087] S322: During the casting process, multiple thermocouples embedded in key parts of the mold continuously send temperature data back to the central control system.

[0088] In step S322, the control system compares these real-time data with the preset sequential solidification temperature curve.

[0089] S323: The control system dynamically and finely adjusts the flow rate and time of the cooling medium in each cooling circuit based on real-time temperature data.

[0090] In step S323: The temperature core control objective is to force the casting to form and maintain a clear "bottom-up" solidification direction. This sequence ensures that during the final solidification and shrinkage of the wheel rim, the upstream risers and even the gating system can still provide liquid metal for effective feeding.

[0091] S324: When the thermocouple detects that the temperature of the thickest part of the casting body (usually the upper rim) has dropped to about 400℃~450℃, the system determines that cooling is complete.

[0092] In step S324, 450°C can be preferentially selected as the cooling endpoint criterion because for aluminum alloys such as A356.2, this temperature is significantly lower than its solidus temperature, the casting skeleton has been fully formed, and it has sufficient strength and dimensional stability, so that the mold opening operation can be carried out to speed up the casting production speed, while avoiding casting deformation or thermal cracking due to premature mold opening.

[0093] S4: Sequential mold opening, casting removal, systematic post-processing, and final quality verification.

[0094] S41: Multi-step sequential mold opening and automatic robot part removal.

[0095] S411: After the cooling completion alarm light illuminates, the mold opening can be completed automatically or manually, with the same operation process. Taking manual mold opening as an example, the operator first presses the "Lower Mold Down" button, and the lifting cylinder of the lower mold 9 moves the lower mold 9, the side mold 20, and the casting downwards together, allowing the casting to be released from the constraint of the upper mold 1; the operator then presses the "Upper Mold Lock Open" button, and the locking mechanism of the upper mold 1 opens; the operator then presses the "Upper Mold Open" button, and the upper mold 1 flips open, leaving the top of the casting unobstructed.

[0096] S412: The operator then presses the "Side Mold Open" button, and all the multiple drive cylinders of the side molds 20 move outward smoothly and a sufficient distance in sync, releasing the constraint on the radial profile of the wheel rim.

[0097] S413: The operator then presses the "eject" button, and the ejection system in the lower mold 9 is activated. The ejector plate 26 moves upward under the push of the hydraulic cylinder, and the solidified wheel rim casting is smoothly and synchronously ejected from the lower mold core by the evenly distributed ejector rods 18.

[0098] In steps S411-S413, the mold opening logic proceeds sequentially from the upper mold 1 to the side mold 20 to the ejector, thus avoiding mechanical damage, tearing, or deformation caused by irregular stress when the casting is still in a high-temperature brittle state.

[0099] S414: A part-picking robot equipped with a vision positioning system, which immediately and accurately clamps the casting after it is ejected, removes it from the mold, and smoothly transfers it to the subsequent worktable via a roller conveyor line.

[0100] S42: Standardized post-treatment and performance-enhancing heat treatment for castings.

[0101] S421: After the casting has cooled to room temperature naturally on the conveyor line, use tools such as band saws to clean the gating system, overflow trough, slag bag, and flash burrs.

[0102] S422: The cleaned castings are solution treated at (535±5)℃ and held for (6±0.5) hours to allow the alloying elements to dissolve completely; S423: After reaching (6±0.5) hours, quickly transfer to (80±10)℃ warm water for quenching to obtain a supersaturated solid solution; S424: After completion, age the tissue at (145±5)℃, keep it at that temperature for (5±0.5) hours, and then air cool it to stabilize the tissue and precipitate the strengthening phase.

[0103] S43: Comprehensive quality verification and quantitative performance evaluation of the product.

[0104] S431: For wheel rim castings that have undergone standardized processing, each piece shall be subjected to X-ray non-destructive testing. Castings that pass the testing shall be heat-treated, while those that fail the testing shall be scrapped directly.

[0105] In step S431: the grade and quantity of defects such as porosity, shrinkage, and inclusions are detected.

[0106] S432: From the batch of heat-treated products, sample bars are periodically cut from three evenly distributed points on the upper and lower parts of the casting rim, and mechanical properties are tested on a material testing machine.

[0107] The statistical results of mechanical property tests on batch products consistently show that the average tensile strength exceeds 280 MPa and the average elongation after fracture exceeds 8%, which is a direct result of the synergistic effect of multiple core technologies in this process. First, the stable pouring system, combined with mold tilting and multi-speed control, achieves smooth laminar flow filling of molten metal without impact, greatly reducing defects such as oxide inclusions and air entrapment from the source.

[0108] Secondly, the combination of optimizing the feeding posture by tilting the casting machine back to a horizontal position and sequential solidification and cooling technology under temperature field monitoring eliminates internal shrinkage porosity and improves the density of the casting.

[0109] Third, precise clean smelting control and T6 heat treatment process further optimize the material matrix structure and fully release the material's performance potential.

[0110] S44: Perform full-size machining and turning on the casting, and drill valve holes and wire holes.

[0111] S441: Machining reference surface. Using the cast lower rim as the clamping surface, the riser end of the wheel rim is machined as the reference surface, and then the wheel is lowered after machining.

[0112] S442: Turning sequence, clamped on the reference surface, turning half of the wheel rim's outer dimensions, then transferred to another lathe after turning.

[0113] S443: Second turning sequence, re-clamp the wheel with the turned rim as the clamping surface, and send it down after turning the entire wheel rim.

[0114] S444: Valve hole. After clamping, drill the valve hole at the specified position.

[0115] S445: Drill wire holes. After clamping, process the wire holes on one side according to the process requirements. Then, re-clamp and align the wire holes on the other side.

[0116] S444 and S445 can be completed simultaneously on a five-axis machining center.

[0117] Wheel rims produced by this process have significantly better mechanical properties and fatigue life than traditional gravity casting and ordinary low-pressure casting products. At the same time, for complex wheel rim products, its production cost and production efficiency are more advantageous compared to the profile extrusion welding process.

[0118] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A wheel rim production process based on tilt casting forming, characterized in that, Includes the following steps: S1: Melt A356.2 aluminum alloy, adjust the aluminum liquid composition to the range of Fe≤0.19%, Mg: 0.30%~0.45%, Si: 6.5%~7.5%, and refine and quantitatively set the aluminum liquid for pouring; S2: After the mold is closed, place a filter screen at the mold pouring port, drive the mold to tilt so that the ladle moves downward. When the angle between the upper surface of the mold and the horizontal plane reaches (45±5)°, the upper end of the ladle is parallel to the ground. Start injecting a fixed amount of molten aluminum into the ladle from the quantitative furnace. Drive the mold and ladle to tilt back and start pouring, and start pouring with the first angular velocity ω1. When the angle between the upper surface of the mold and the horizontal plane is less than (30±5)°, pour the main body of the casting with the second angular velocity ω2, which is greater than ω1. When the angle between the upper surface of the mold and the horizontal plane is less than (10±3)°, decelerate the filling with the third triangular velocity ω3, which is less than ω2. The last bit of molten aluminum and oxide scale remain in the ladle to cool. S3: After tilting the mold upwards to a horizontal position, the filling process is completed. Then, the flipping casting machine is locked, and the cooling system is started. The cooling process is then adjusted according to the real-time temperature data of the thermocouples inside the mold. S4: Remove the aluminum oxide scale from the ladle, and perform the following steps on the casting: mold opening, part removal, air cleaning of the mold cavity, mold closing, tilting pouring, casting cooling, removal of the pouring riser, X-ray inspection, heat treatment, and machining.

2. The wheel rim production process based on slant casting forming according to claim 1, characterized in that, Step S1 specifically includes: S11: At (740±10)℃, an inert gas is used to carry the refining agent and spray it into the depth of the aluminum liquid for a spraying time of not less than 3 minutes. S12: After refining, aluminum-strontium alloy is added to the melt every half hour for modification treatment, and magnesium blocks are added every hour for fine-tuning of the composition; S13: Strictly control the temperature of the molten aluminum within the range of (700±20)℃; S14: The quantitative pouring of aluminum liquid is accomplished by the electromagnetic pump of the quantitative furnace and the Coriolis mass flow meter, and the quantitative accuracy is controlled within ±0.3%.

3. The wheel rim production process based on slant casting forming according to claim 1, characterized in that, Step S2 specifically includes: S21: Before performing tilting filling, preheat the mold to 180℃~250℃ and spray a double-layer coating on the mold cavity: the first layer is a silica sol-based coating to form a dense underlayer of about 0.1mm thick, and the second layer is a coating containing nano-graphite to form a lubricating functional layer of about 0.3mm thick. S22: Before mold closing and pouring, use dry compressed air to thoroughly blow away impurities in the cavity in the order of mold core first and then slide rail. S23: The first angular velocity ω1 is (5.0±1.0)° / s, the second angular velocity ω2 is (7.0±1.0)° / s, and the third angular velocity ω3 is (5.0±1.0)° / s; S24: Before pouring, place a high-temperature resistant filter screen at the pouring port and use a preheated ladle to gently skim off the slag on the surface of the molten aluminum in the ladle.

4. The wheel rim production process based on slant casting forming according to claim 3, characterized in that, In step S23: The initial pouring was carried out at an angular velocity of (5.0±1.0)° / s, which was intended to allow the molten aluminum to quickly establish a stable molten metal pad at the bottom of the cavity; The casting body is poured and filled with an angular velocity of (7.0±1.0)° / s, so that the flow of molten metal can quickly fill the entire wheel rim cavity; The end-stage deceleration filling is performed at an angular velocity of (5.0±1.0)° / s to reduce the amount of oxide scale, particulate impurities and gas that are flushed into the casting body by the molten aluminum, and to facilitate the rise of oxide scale, particulate impurities and gas to the riser.

5. The tilt-casting based wheel rim production process according to claim 1, characterized in that, Step S3 specifically includes: S31: After filling is complete, stop and lock the mold in a horizontal position; S32: Activate the partitioned cooling system, which includes several first cooling circuits evenly distributed in a circle at the bottom of the lower mold, with the bottom of the cooling holes of the first cooling circuits opening inside the lower end of the wheel rim cavity; several second cooling circuits evenly distributed in a circle at the outside of each side mold, with the bottom of the cooling holes of the second cooling circuits opening below the wheel rim at the upper end of the corresponding wheel rim cavity of the side mold; and several third cooling circuits evenly distributed in a circle at the top of the upper mold, with the bottom of the cooling holes of the third cooling circuits opening inside the upper end of the wheel rim cavity of the upper mold. S33: Based on the real-time temperature data, dynamically adjust the medium flow rate and time of each cooling circuit to force the casting to form a solidification sequence from the lower end of the wheel rim to the upper end of the wheel rim; S34: When the temperature at the center of the casting drops to 400℃~450℃, cooling is considered complete.

6. The wheel rim production process based on inclined casting as described in claim 1, characterized in that, Step S4 specifically includes: S41: The sequential mold opening is performed in the following order: After cleaning the oxide scale in the ladle, the mold is opened: First, the lower mold and side molds, together with the casting, are moved down to separate the upper mold from the casting. The upper mold locking mechanism is opened, the upper mold is flipped upward to open, all side molds are opened simultaneously, the lower mold ejection mechanism is activated to eject the casting, and the robot arm grabs the casting and transfers it to the cooling area; Mold closing: Using dry compressed air, impurities in the cavity are thoroughly blown away in the order of mold core first and then slide rail. The ejector rod of the lower mold ejection mechanism is reset first, all side molds are closed simultaneously, the upper mold is flipped downward to the position, the upper mold locking mechanism is closed, the lower mold and side molds rise to close with the upper mold, the tilting flipping mechanism flips the mold downward, a high-temperature resistant filter screen is placed at the funnel of the gating system, a metered amount of aluminum liquid is injected into the ladle by the metered furnace, the tilting casting machine is reset upward and the aluminum liquid is poured and filled, and the casting solidifies and cools sequentially; the mold opening and part removal are repeated, and after the casting cools, the gating riser is removed, and the internal structure is inspected with an X-ray flaw detector; S42: The heat treatment is T6 heat treatment, specifically: solution treatment at (535±5)℃ for (6±0.5) hours, water quenching at (80±10)℃, aging at (145±5)℃ for (5±0.5) hours, followed by air cooling. S43: Periodically cut sample bars from three evenly distributed points on the upper and lower parts of the casting rim and perform mechanical property tests on a material testing machine; S44: Perform full-size machining and turning on the casting, and drill valve holes and wire holes.

7. The wheel rim production process based on inclined casting as described in claim 1, characterized in that, Before performing step S2, the process further includes: preheating the mold to 180°C to 250°C and spraying a double-layer coating on the mold cavity. The first layer is a silica sol-based coating to form a dense underlayer, and the second layer is a coating containing nano-graphite to form a lubricating functional layer.

8. A cast wheel rim, characterized in that, The wheel rim is manufactured using the wheel rim production process based on inclined casting as described in any one of claims 1 to 7.

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