A processing technology of aluminum alloy forged wheel hub

Abstract

The application relates to a processing technology of aluminum alloy forged wheel hubs, and relates to the technical field of aluminum alloys, which comprises the steps of ingot casting, cutting, heating, forging, solid solution treatment, spinning forming, aging treatment, machining and surface treatment. In the application, the solid solution treatment step is arranged before the spinning forming step, so that the plasticity of the forged piece is enhanced, the probability of work hardening during spinning forming of the forged piece is reduced, and compared with the spinning forming before the solid solution treatment, the probability of coarse grain phenomenon in the rim part of the wheel hub is reduced, so that the mechanical properties of the rim part of the wheel hub are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum alloy, in particular to a processing technology of aluminum alloy forged wheel hub. BACKGROUND

[0002] In recent years, aluminum alloy forged wheel hub is more and more used to replace steel wheel to be installed on vehicles, and the processing technology of conventional aluminum alloy forged wheel hub is prone to cause defects such as stacking and cracking in the process of forging, and the existence of stacking and cracking defects destroys the continuity of metal organization, and the aluminum alloy cannot be pressed in the subsequent extrusion or calendering process, thereby reducing the processing performance of the aluminum alloy.

[0003] The reasons for causing stacking and cracking are as follows: one is that there is dendritic segregation in the production process of the ingot, and this problem must be eliminated or reduced by designing chemical composition and homogenizing treatment; the other is that the processing technology in the process of forging, even if the chemical composition of the aluminum alloy ingot is reasonable, but without good forging process, the final aluminum alloy forged wheel hub will still have defects such as stacking and cracking.

[0004] Therefore, the present application provides a processing technology of aluminum alloy forged wheel hub to reduce the probability of stacking and cracking, and thereby improve the performance and safety factor of the aluminum alloy forged wheel hub. SUMMARY

[0005] In order to improve the performance and safety factor of the aluminum alloy forged wheel hub, the present application provides a processing technology of aluminum alloy forged wheel hub.

[0006] The present application provides a processing technology of aluminum alloy forged wheel hub, which adopts the following technical scheme:

[0007] A processing technology of aluminum alloy forged wheel hub, comprising the following steps:

[0008] Ingot: the silicon, magnesium, copper, manganese, chromium, iron, titanium, zinc and aluminum are cast into an aluminum alloy ingot;

[0009] Cutting: the aluminum alloy ingot is cut into a blank;

[0010] Heating: the blank is placed in a heating furnace with a temperature of 545±3℃ for heating and heat preservation for 3h;

[0011] Forging: the blank is placed in a forging die for forging, thereby forming a hot forging piece;

[0012] Solution treatment: the forging piece is placed in a heating furnace with a temperature of 540±3℃ for heating and heat preservation for 4h; and then the solution treated forging piece is placed in water with a temperature of 40-60℃ for quenching;

[0013] spinning forming: the quenched forging is placed in a spinning machine to be spun into a hollow rotary body hub blank;

[0014] aging treatment: the hollow rotary body hub blank is heated in a heating furnace at a temperature of 180±3℃ for 10h;

[0015] machining: the hollow rotary body hub blank is machined to obtain an aluminum alloy hub;

[0016] surface treatment: the aluminum alloy hub is polished, coated and painted.

[0017] By adopting the above technical scheme, the solid solution treatment step is arranged before the spinning forming step, so that the plasticity of the forging is enhanced, and the probability of work hardening during spinning forming of the forging is reduced; compared with spinning forming before solid solution treatment, the probability of coarse grain phenomenon in the rim part of the hub is also reduced, so that the mechanical properties of the rim part of the hub are greatly improved. During solid solution treatment, the temperature of the heating furnace is set to 540±3℃, which can maximize the dissolution of silicon and magnesium in the matrix of the forging, and also prevents the forging from being overburned; controlling the water temperature at 40-60℃ can well control the quenching effect of the forging, so that the forging can form a supersaturated solid solution, laying a good foundation for the next aging. The aging temperature is set to 180±3℃, which can maximize the aging efficiency and reduce the probability of coarse grain. After solid solution treatment, the magnesium-silicon phase in the aluminum alloy is redistributed, and then the metallographic gap is formed in the aluminum alloy; after aging treatment, the magnesium-silicon phase is redistributed again, and then the gap in the aluminum alloy is filled, forming a needle piercing effect, improving the organizational stress between the grains, and then strengthening the strength and hardness of the aluminum alloy.

[0018] Optionally, in the ingot casting step, the mass percentage of each chemical component in the aluminum alloy ingot is: 0.705% of silicon, 1.015% of magnesium, 0.290% of copper, 0.165% of manganese, 0.210% of chromium, 0.025% of titanium, 0.150% of iron, 0.021% of zinc, and the balance of aluminum.

[0019] Silicon and magnesium are commonly used strengthening elements of aluminum alloy, but their content is too high, which will lead to uneven distribution of grain boundary and intracrystalline. Copper is also a commonly used strengthening element, but its content is too high, which will also lead to the problem of grain boundary segregation. By adopting the above technical scheme, the uniformity of each component of the grain boundary and the intracrystalline is reduced by controlling the content and proportion of silicon, magnesium and copper elements. Titanium can form stable oxides in the melt, which can act as crystal nucleus to promote grain refinement, thereby improving the strength and plasticity of aluminum alloy. Moreover, titanium can react with aluminum oxide to form titanium dioxide, which helps to remove gas in aluminum alloy and reduce the generation of pores.

[0020] Optionally, the cutting step is further provided with an annealing step before the cutting step;

[0021] Annealing: the aluminum alloy ingot is heated to 550±3℃ in a heating furnace, and then the aluminum alloy ingot is cooled to room temperature.

[0022] By adopting the above technical scheme, the aluminum alloy ingot is heated to 550±3℃, so that the non-equilibrium crystalline phase is dissolved into the matrix, and then the matrix composition is homogenized to create conditions for subsequent plastic processing. At the same time, the number of residual crystalline phases is reduced as much as possible to eliminate the low-melting-point eutectic and residual phases in the ingot structure, improve the hot plasticity of the ingot, improve the toughness and fatigue life of the alloy, improve the solid solubility of alloying elements in the matrix, reduce the precipitation of coarse substances in the aluminum alloy ingot, avoid intracrystalline segregation, and reduce unbalanced phases.

[0023] Optionally, in the annealing step, the aluminum alloy ingot is heated to 500±3℃, and then heated to 550±3℃ for 10h; then the aluminum alloy ingot is transferred to a cooling chamber for cooling, and the transfer time is not more than 10min; the cooling chamber uses a spray cooling method to cool the aluminum alloy ingot to below 300℃ within 30min; then the aluminum alloy ingot is rapidly cooled by water flow to reduce the temperature of the aluminum alloy ingot to room temperature.

[0024] By adopting the above technical scheme, the aluminum alloy ingot is first heated to 500±3℃ and kept for 2h when heated, which can make the aluminum alloy ingot uniformly heated, reducing the probability of deformation of the aluminum alloy ingot due to uneven heating. Then, the aluminum alloy ingot is slowly cooled by spray cooling to reduce the internal stress of the aluminum alloy ingot, thereby reducing the probability of cracks and improving the plasticity of the aluminum alloy ingot.

[0025] Optionally, the forging step includes a pre-forging pressing step, a forming forging pressing step and a punching step.

[0026] Pre-forging pressing: using a pre-forging press to forge the blank, the pressure of the pre-forging press is 3000t, and the pressing speed is 15mm / s;

[0027] Forming forging: using a forming forging machine to forge the blank, the pressure of the pre-forging machine is 7000t, and the pressing speed is 8mm / s;

[0028] Punching: using a punching forging machine to forge the blank, the pressure of the pre-forging machine is 200t, and the punching and expanding hole of the forged piece is performed.

[0029] By adopting the above technical scheme, when the blank is forged, the mold works on the blank, thereby increasing the temperature of the blank; therefore, during pre-forging and forming forging, the forging piece is heated at a slow speed by appropriate pressure and forging speed, thereby reducing the probability of grain coarsening in the blank; and the heat loss of the blank is reduced, so that the plasticity of the blank is maintained. Moreover, during forging, the blank is first pre-forged, so that the first deformation of the blank is small, and then the blank is formed by forging; in this way, the probability of stacking and cracking during forging is reduced.

[0030] Optionally, the forging step further comprises a mold pretreatment step, which is arranged before the pre-forging step;

[0031] Mold pretreatment: heating the forging die to 400-500℃, and spraying lubricant on the working surface of the forging die.

[0032] By adopting the above technical scheme, when the blank is forged, the blank transmits temperature to the mold, and heating the forging die to 400-500℃ can reduce the heat transmitted from the blank to the forging die, thereby reducing the probability of coarse grain.

[0033] Optionally, an online quenching step is arranged between the forging and the solid solution treatment step;

[0034] Online quenching: quenching the hot forged piece in water at 40-60℃, and the quenching time is 130s.

[0035] By adopting the above technical scheme, after online quenching, the driving force of recrystallization of the forged piece is reduced, so that during subsequent solid solution, only a small amount of recrystallization occurs, thereby producing higher precipitation strengthening effect during subsequent aging process, and improving the mechanical properties of the alloy.

[0036] Optionally, in the solid solution treatment step, the time interval from taking out the forged piece from the heating furnace to the beginning of quenching of the forged piece is less than 17s.

[0037] By adopting the above technical scheme, the quenching transfer time is controlled within 17s, which can prevent the re-precipitation of silicon and magnesium elements, thereby reducing the occurrence of solid solution saturation degree reduction.

[0038] Optionally, a surface rolling step is arranged between the machining step and the surface treatment step,

[0039] Surface rolling: the surface of the aluminum alloy wheel hub is rolled, and the surface of the aluminum alloy wheel hub is sunken by 0.5mm.

[0040] By adopting the technical scheme, after machining, the aluminum alloy wheel hub has been formed, and then the surface of the aluminum alloy wheel hub is rolled, so that the surface hardness of the aluminum alloy wheel hub can be improved.

[0041] In summary, the present application has the following at least one beneficial technical effect:

[0042] 1. By arranging the solid solution treatment step before the spinning forming step, the plasticity of the forging is enhanced, and when the forging is spun formed, the probability of work hardening can be reduced; compared with spinning before solid solution treatment, the probability of coarse grain phenomenon in the rim part of the wheel hub can also be reduced, so that the mechanical properties of the rim part of the wheel hub are greatly improved. Then during the solid solution treatment, the temperature of the heating furnace is set to 540±3℃, which can maximize the dissolution of silicon and magnesium in the matrix of the forging, and also prevent the forging from being overburned; and the quenching transfer time is controlled within 17s, which can prevent the re-precipitation of silicon and magnesium elements, and further reduce the occurrence of solid solution saturation degree reduction; the water temperature is controlled at 40-60℃, which can well control the quenching effect of the forging, so that the forging can form a supersaturated solid solution, and lay a good foundation for the next aging. The aging treatment temperature is set to 180±3℃, which can maximize the aging efficiency and reduce the probability of coarse grain. After solid solution treatment, the magnesium-silicon phase in the aluminum alloy will be redistributed, and then the metallographic gap in the aluminum alloy will be formed; after aging treatment, the magnesium-silicon phase is redistributed again, and then the gap in the aluminum alloy is filled, forming a needle piercing effect, improving the organizational stress between the grains, and then strengthening the strength and hardness of the aluminum alloy.

[0043] 2. By setting the annealing step, the aluminum alloy ingot is first heated to 500±3℃ and kept for 2h when heated, which can make the aluminum alloy ingot uniformly heated, reduce the probability of deformation of the aluminum alloy ingot due to uneven heating; the aluminum alloy ingot is heated to 550±3℃, so that the non-equilibrium crystalline phase is dissolved into the matrix, and then the matrix composition is homogenized, which creates conditions for subsequent plastic processing; at the same time, the number of residual crystalline phases is reduced as much as possible to eliminate the low-melting-point eutectic and residual phases in the ingot structure, improve the hot plasticity of the ingot, improve the toughness and fatigue life of the alloy, improve the solid solubility of alloying elements in the matrix, reduce the precipitation of coarse substances in the aluminum alloy ingot, avoid intracrystalline segregation, reduce unbalanced phases, and use spray cooling in the cooling chamber to cool the aluminum alloy ingot to below 300℃ within 30min; then the aluminum alloy ingot is rapidly cooled using water flow to reduce the temperature of the aluminum alloy ingot to room temperature.

[0044] 3. By setting the online quenching step, the driving force for recrystallization of the forged piece is reduced, so that only a small amount of recrystallization occurs while obtaining a higher alloy element supersaturation in the subsequent solid solution, thereby producing a higher precipitation strengthening effect in the subsequent aging process and improving the mechanical properties of the alloy.

[0045] 4. By setting the surface rolling step, the surface hardness of the aluminum alloy wheel hub is improved. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is a flowchart of the embodiment;

[0047] Figure 2 is a microstructure metallographic chart of the blank after the forging step in the embodiment;

[0048] Figure 3 is a microstructure metallographic chart of the rim portion of the wheel hub when the spinning forming step is performed before the solid solution treatment step;

[0049] Figure 4 is a microstructure metallographic chart of the rim portion of the wheel hub after the spinning forming step in the embodiment. DETAILED DESCRIPTION

[0050] The application will be further described in detail below. Figures 1 to 4 The application will be further described in detail below.

[0051] The embodiment discloses a processing technology of an aluminum alloy forged wheel hub, referring to Figure 1 , the processing technology of the aluminum alloy forged wheel hub comprises the following steps:

[0052] S1: Ingot casting: Silicon with a mass percentage of 0.705%, magnesium with a mass percentage of 1.015%, copper with a mass percentage of 0.290%, manganese with a mass percentage of 0.165%, chromium with a mass percentage of 0.210%, titanium with a mass percentage of 0.025%, iron with a mass percentage of 0.150%, zinc with a mass percentage of 0.021%, and the balance of aluminum are cast into an aluminum alloy ingot. In the aluminum alloy ingot, sub-micron magnesium silicon phases are distributed in the alloy matrix, and larger magnesium silicon phases are distributed on the grain boundaries and sub-grain boundaries; the copper element is completely dissolved into the matrix, the manganese element is completely dissolved into the matrix, and the compounds of chromium and aluminum, titanium and aluminum are distributed on the grain boundaries.

[0053] S2: Annealing: The aluminum alloy ingot is heated to 500±3℃, and held for 2h, then heated to 550±3℃, and held for 10h; then the aluminum alloy ingot is transferred to a cooling chamber for cooling, and the transfer time is not more than 10min; the cooling chamber uses a spray cooling method to cool the aluminum alloy ingot to below 300℃ within 30min; then the aluminum alloy ingot is rapidly cooled using water flow to reduce the temperature of the aluminum alloy ingot to room temperature.

[0054] When heating, the aluminum alloy ingot is first heated to 500±3℃ and held for 2h, which can uniformly heat the aluminum alloy ingot and reduce the probability of deformation of the aluminum alloy ingot due to uneven heating; then the aluminum alloy ingot is heated to 550±3℃, which makes the non-equilibrium crystalline phase dissolve into the matrix, and further homogenizes the matrix composition, creating conditions for subsequent plastic processing; at the same time, the number of residual crystalline phases is as low as possible to eliminate the low-melting-point eutectic and residual phases in the ingot structure, improve the hot plasticity of the ingot, improve the toughness and fatigue life of the alloy, improve the solid solubility of alloying elements in the matrix, reduce the precipitation of coarse substances in the aluminum alloy ingot, avoid intragranular segregation, and reduce unbalanced phases. Then, the aluminum alloy ingot is slowly cooled by spray cooling to reduce the internal stress in the aluminum alloy ingot, thereby reducing the probability of cracks and improving the plasticity of the aluminum alloy ingot.

[0055] S3: Cutting: The aluminum alloy ingot is cut into a blank.

[0056] S4: Heating: The blank is placed in a heating furnace at a temperature of 545±3℃ and heated for 3h; the temperature of the blank when it is discharged from the furnace is controlled at 520±3℃. At this temperature, the blank of the present embodiment has the best plasticity and the smallest deformation resistance, thereby facilitating forging.

[0057] S5: Forging: The blank is placed in a forging die to be forged, thereby forming a hot forged piece; the forging step S4 includes a die pretreatment step S5-1, a pre-forging step S5-2, a forming forging step S5-3, and a punching step S5-4.

[0058] S5-1: mold pretreatment: the forging die is heated to 400-500℃, and a lubricant is sprayed on the working surface of the forging die. When the blank is forged, the blank will transfer the temperature to the die, and heating the forging die to 400-500℃ can reduce the heat transferred from the blank to the forging die, thereby reducing the probability of the formation of coarse grains.

[0059] S5-2: pre-forging: the blank is forged using a pre-forging press, the pressure of the pre-forging press is 3000t, and the pressing speed is 15mm / s;

[0060] S5-3: forming forging: the blank is forged using a forming forging press, the pressure of the pre-forging press is 7000t, and the pressing speed is 8mm / s;

[0061] S5-4: piercing: the blank is forged using a piercing forging press, the pressure of the pre-forging press is 200t, and the blank is pierced to form a hot forged piece.

[0062] Reference Figure 2 When the blank is forged, the die works on the blank, thereby increasing the temperature of the blank; therefore, during pre-forging and forming forging, the forging piece is heated at a slow speed by using appropriate pressure and forging speed, which reduces the probability of grain coarsening in the blank, and reduces the heat loss of the blank, so that the blank maintains good plasticity. Moreover, during forging, the blank is first pre-forged to reduce the first deformation of the blank, and then the blank is formed; in this way, the probability of stacking and cracking during forging can be reduced.

[0063] S6: online quenching: the hot forged piece is placed in water at 40-60℃ for quenching, thereby forming a forged piece, the quenching time is 130s, and the temperature of the forged piece after quenching is 50±3℃.

[0064] After online quenching, the driving force for recrystallization of the forged piece is reduced, so that during subsequent solid solution, a higher supersaturation of alloying elements is obtained, and only a small amount of recrystallization occurs, thereby producing a higher precipitation strengthening effect during subsequent aging, and improving the mechanical properties of the alloy.

[0065] S7: solid solution treatment: the quenched forged piece is placed in a heating furnace at a temperature of 540±3℃ for heating, and the heating time is 4h; then the heated forged piece is placed in water at 40-60℃ for quenching; wherein the time interval from taking the forged piece out of the heating furnace to starting quenching of the forged piece is less than 17s.

[0066] In the solid solution treatment, the temperature of the heating furnace is set at 540±3℃, which can maximize the dissolution of silicon and magnesium in the matrix of the forging, and also does not cause the forging to be overburned; and the quenching transfer time is controlled within 17s, which can prevent the re-precipitation of silicon and magnesium elements, and further reduce the occurrence of solid solution saturation reduction; and the water temperature is controlled at 40-60℃, which can well control the quenching effect of the forging, so that the forging can form a supersaturated solid solution, laying a good foundation for the next aging.

[0067] S8: spinning forming: the forging after the solid solution treatment is put into a spinning machine for spinning forming, and then a hub blank is formed. The plasticity of the forging after the solid solution treatment is enhanced, and the probability of work hardening can be reduced when the forging is spun and formed. Referring to Figure 3 and Figure 4 , compared with spinning forming before the solid solution treatment, the probability of coarse grain phenomenon in the rim part of the hub can also be reduced, which greatly improves the mechanical properties of the rim part of the hub.

[0068] The spinning forming step is performed before the solid solution treatment step and the spinning forming step is performed after the solid solution treatment step, and the test data of the rim part of the hub are shown in the following table:

[0069] From the above table, it can be concluded that compared with the spinning forming step performed after the solid solution treatment step, the spinning forming step performed before the solid solution treatment step can make the rim part of the hub have greater tensile strength and yield strength.

[0070] S9: aging treatment: the hub blank is placed in a heating furnace with a temperature of 180±3℃ for heating and holding for 10h. The temperature of the aging treatment is set at 180±3℃, which can maximize the aging efficiency and reduce the probability of coarse grain. After the solid solution treatment, the magnesium-silicon phase in the aluminum alloy will be redistributed, and then the metallographic gap in the aluminum alloy will be formed; after the aging treatment, the magnesium-silicon phase is redistributed again, and then the gap in the aluminum alloy is filled, forming a needle-piercing effect, improving the organizational stress between the grains, and then strengthening the strength and hardness of the aluminum alloy.

[0071] Compared with the 6061 aluminum alloy hub of the traditional process, the mechanical property test data of each part of the hub blank after the aging treatment are shown in the following table:

[0072] From the above table, it can be concluded that after the aging treatment of the hub blank produced by the present embodiment, the tensile strength, yield strength and elongation after fracture of each part of the hub blank are greatly improved compared with the hub blank produced by the traditional process.

[0073] S10: machining: the hollow rotating body hub blank is machined to obtain an aluminum alloy hub.

[0074] S11: surface rolling: the surface of the aluminum alloy wheel hub is rolled to sink the surface of the aluminum alloy wheel hub by 0.5 mm. In this way, the surface hardness of the aluminum alloy wheel hub can be improved. The surface hardness test data of the aluminum alloy wheel hub before and after surface rolling are shown in the following table:

[0075] From the above table, it can be concluded that after surface rolling, the hardness of each part of the wheel hub is greatly improved compared with the wheel hub blank before surface rolling.

[0076] S12: surface treatment: polishing, coating and painting treatment are performed on the aluminum alloy wheel hub.

[0077] The implementation principle of the processing technology of the alloy forged wheel hub of the embodiment is:

[0078] By controlling the content and proportion of silicon, magnesium and copper elements, the unevenness of each component at the grain boundary and within the grain can be reduced. Titanium can form stable oxides in the melt, which can act as crystal nuclei to promote grain refinement, thereby improving the strength and plasticity of the aluminum alloy. Moreover, titanium can react with aluminum oxide to form titanium dioxide, which helps to remove gas from the aluminum alloy and reduce the generation of pores.

[0079] By setting the annealing step, non-equilibrium crystalline phases are dissolved into the matrix, which homogenizes the matrix composition and creates conditions for subsequent plastic processing. At the same time, the number of residual crystalline phases is reduced as much as possible to eliminate low-melting-point eutectic and residual phases in the ingot structure, improve the hot plasticity of the ingot, increase the toughness and fatigue life of the alloy, increase the solid solubility of alloying elements in the matrix, reduce the precipitation of coarse substances in the aluminum alloy ingot, avoid intracrystalline segregation, and reduce unbalanced phases.

[0080] During forging, the forging die is first heated to reduce the heat transfer from the blank to the forging die, thereby reducing the probability of coarse grain formation. Then, by using appropriate pressure and forging speed, the heating rate of the forged part is slow, which reduces the probability of grain coarsening in the blank. Moreover, it can reduce the heat loss of the blank and maintain good plasticity. Moreover, during forging, the blank is first pre-forged with a small first deformation, and then the blank is formed by forging. In this way, the probability of stacking and cracking during forging can be reduced.

[0081] Then, online quenching is performed, which reduces the driving force for recrystallization of the forged part, so that during subsequent solid solution, only a small amount of recrystallization occurs, thereby producing a higher precipitation strengthening effect during the subsequent aging process, which improves the mechanical properties of the alloy.

[0082] After solid solution treatment, the temperature of the heating furnace is set at 540±3 DEG C during the solid solution treatment, which can maximize the dissolution of silicon and magnesium in the matrix of the forging, and the forging is not overburned; the quenching transfer time is controlled within 17s, which can prevent the re-precipitation of silicon and magnesium elements, and further reduce the occurrence of solid solution saturation degree reduction. The water temperature is controlled at 40-60 DEG C, which can well control the quenching effect of the forging, so that the forging can form a supersaturated solid solution, and lay a good foundation for the next aging.

[0083] After spinning forming, the solid solution treatment step is arranged before the spinning forming step, so that the plasticity of the forging is enhanced, and the probability of work hardening phenomenon during the spinning forming of the forging is reduced; compared with the spinning forming before the solid solution treatment, the probability of coarse grain phenomenon in the rim part of the hub is also reduced, which greatly improves the mechanical properties of the rim part of the hub.

[0084] After aging treatment, the magnesium-silicon phase in the aluminum alloy is redistributed after the solid solution treatment, and then the metallographic gap is formed in the aluminum alloy; after the aging treatment, the magnesium-silicon phase is redistributed again, and then the gap in the aluminum alloy is filled, the needle piercing effect is formed, the organizational stress between the grains is improved, and the strength and hardness of the aluminum alloy are strengthened. The temperature of the aging treatment is set to 180±3 DEG C, which can maximize the aging efficiency and reduce the probability of coarse grain.

[0085] After machining, the forging forms an aluminum alloy hub, and then surface rolling is performed, under the action of the surface rolling, the surface hardness of the aluminum alloy hub is improved.

[0086] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A process for machining an aluminum alloy forged wheel hub, characterized by: Comprise the following steps: Ingot casting: silicon, magnesium, copper, manganese, chromium, iron, titanium, zinc, aluminum are cast into aluminum alloy ingot; the mass percentage of each chemical component in the aluminum alloy ingot is: 0.705% of silicon, 1.015% of magnesium, 0.290% of copper, 0.165% of manganese, 0.210% of chromium, 0.025% of titanium, 0.150% of iron, 0.021% of zinc and the balance of aluminum; Annealing: heat the aluminum alloy ingot to 500±3℃, keep warm for 2h, then heat to 550±3℃, keep warm for 10h; then transfer the aluminum alloy ingot to the cooling chamber, the transfer time is not more than 10min; the cooling chamber uses spray cooling method, the aluminum alloy ingot is cooled to below 300℃ within 30min; then use water flow to quickly cool the aluminum alloy ingot, so that the temperature of the aluminum alloy ingot is reduced to room temperature; Cutting: cut the aluminum alloy ingot into a blank; Heating: place the blank in a heating furnace with a temperature of 545±3℃ and heat for 3h; Forging: put the blank into the forging die to forge, thereby forming a hot forged piece; Online quenching: place the hot forged piece in water at 40-60℃ for quenching, the quenching time is 130s; Solution treatment: place the forged piece in a heating furnace at a temperature of 540±3℃ and heat for 4h; then place the solution treated forged piece in water at 40-60℃ for quenching; Spinning forming: place the quenched forged piece into a spinning machine for spinning forming, thereby forming a hollow rotating body hub blank; Aging treatment: place the hollow rotating body hub blank in a heating furnace at a temperature of 180±3℃ and heat for 10h; Machining: machine the hollow rotating body hub blank, thereby obtaining an aluminum alloy hub; Surface treatment: polish, coat and paint the aluminum alloy hub.

2. The process for machining of aluminum alloy forged wheel hubs as claimed in claim 1 wherein: The forging step includes a pre-forging step, a forming forging step and a punching step; Pre-forging: use a pre-forging press to forge the blank, the pressure of the pre-forging press is 3000t, and the pressing speed is 15mm / s; Forming forging: use a forming forging press to forge the blank, the pressure of the pre-forging press is 7000t, and the pressing speed is 8mm / s; Punching: use a punching forging press to forge the blank, the pressure of the pre-forging press is 200t, and the forged piece is punched and expanded.

3. The process for machining an aluminum alloy forged wheel hub according to claim 2, characterized in that: The forging step also includes a die pretreatment step, which is arranged before the pre-forging step; Die pretreatment: heat the forging die to 400-500℃ and spray lubricant on the working surface of the forging die.

4. The process for machining an aluminum alloy forged wheel hub according to claim 1, characterized in that: In the solution treatment step, the time interval from taking the forged piece out of the heating furnace to the start of quenching of the forged piece is less than 17s.

5. The process for machining an aluminum alloy forged wheel hub according to claim 1, characterized in that: A surface rolling step is arranged between the machining step and the surface treatment step, Surface rolling: roll the surface of the aluminum alloy hub, so that the surface of the aluminum alloy hub is sunken by 0.5mm.

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