Automobile hub and preparation method thereof

Abstract

The invention discloses an automobile hub and a preparation method thereof. The automobile hub comprises Si, Mg, Ti, Fe, Mn, P, Sb, Zn, Cu, Pb, Sn, Cr, Ni, RE, Sr and Al. Wherein the RE must contain Sc, and the RE also contains at least one selected from the group consisting of La and Ce. The structure of the automobile hub has a smaller secondary dendrite spacing.

Description

Technical Field

[0001] The invention relates to an automobile wheel hub and a preparation method thereof. Background Art

[0002] Cast aluminum alloy is a kind of aluminum alloy with Al as the matrix and Si and Mg as the main alloying elements, which can be strengthened by heat treatment. Cast aluminum alloy has high strength and plasticity, excellent fluidity and castability. The shell cast by it has high airtightness and is an ideal material for the production of automobile wheels. However, the mechanical properties of cast aluminum alloy still need to be further improved.

[0003] CN102366828A discloses a low-pressure casting method for an aluminum alloy automobile wheel hub, which comprises an aluminum alloy containing Si6.8-7.2%, Mg0.6-1.0%, Ti0.1-0.2%, Cu0.5-0.8%, and Zn0.2-0.5% by mass; the total amount of impurity elements such as Fe, Mn, Sn, and Pb does not exceed 0.5%, and the rest is Al. The prepared aluminum alloy is heated in a melting furnace for melting. After the alloy is completely melted, the aluminum liquid temperature is adjusted to 760-770°C, and the Al-Ti-BC refiner is used for refinement treatment, and the addition amount is 0.1-0.2% of the total mass of the smelted alloy; the aluminum liquid temperature is adjusted to 750-760°C, and the rare earth modifier is used for modification treatment, and the addition amount is 0.3-0.5% of the total mass of the smelted alloy; the aluminum liquid temperature is adjusted to 710-730°C, and the refining agent is used for refining treatment, and the addition amount is 0.5-0.6% of the total mass of the smelted alloy; finally, the slag is skimmed, and the aluminum alloy liquid is transferred to the low-pressure casting machine insulation furnace for pouring. The mold is closed, and the mold is locked for casting, and the casting is taken out. The automobile wheel hub casting is subjected to solid solution treatment and complete artificial aging heat treatment. The application does not disclose the composition of the rare earth modifier.

[0004] CN116103543A discloses a recycled high thermal conductivity die-cast aluminum alloy containing rare earth elements, and its chemical composition and the mass percentage of each chemical component are as follows: Si 9.0-12.0%, Fe0.6-1.2%, Cu 0.5-3.0%, Mg 0.1-1.0%, Zn 0.1-1.0%, Mn 0.05-0.4%, Cr 0.03-0.2%, Ti 0.05-0.2%, Ni 0.05-0.2%, Sn≤0.05%, Zr≤0.05%, V≤0.05%, Cd≤0.01%, Pb≤0.01%, Sr 0.01-0.1%, La0.03-0.3%, Ce 0.03~0.3%, the other individual impurities content ≤0.03%, the total impurities content ≤0.15%, the balance is aluminum. The tensile strength and elongation of this alloy are low and it is not suitable for use as a car wheel hub.

[0005] CN116219233A discloses a high thermal conductivity cast aluminum alloy, which comprises Si: 7.5-9.5%, Fe: 0.5-0.8%, Cu: 0.05-0.15%, Mg: 0.1-0.2%, Sr: 0.3-0.6%, B: 0.005-0.02%, Re: 0.01-0.02%, Zn: 0.05-0.15%, Mn: 0.01-0.1 %, Ti: 0.002~0.008%, V: 0.001~0.006%, Cr: 0.02~0.08%, Pb: 0.005~0.015%, Sn: 0.01~0.02%, Sb: 0.002~0.006%, and the balance is Al, and the chemical composition contents of the aluminum alloy satisfy the following relationship: 5≤(Ti+V+Cr+Mn) / B≤35, Si+Sr≥8.0%. The document does not disclose which element Re is, and the alloy has low elongation and tensile strength, and is not suitable for use as a car wheel hub. Summary of the invention

[0006] One object of the present invention is to provide an automobile wheel hub, the metallographic structure of which has a smaller secondary dendrite spacing. Further, the automobile wheel hub has a higher tensile strength. Still further, the automobile wheel hub has a higher yield strength and / or elongation. Another object of the present invention is to provide a method for preparing an automobile wheel hub.

[0007] The present invention achieves the above-mentioned purpose through the following technical solutions.

[0008] In one aspect, the present invention provides an automobile wheel hub, comprising Si 6.8-7.5wt%, Mg 0.25-0.35wt%, Ti 0.05-0.15wt%, Fe 0.05-0.15wt%, Mn 0.01-0.05wt%, P 0.0005-0.003wt%, Sb 0.003-0.01wt%, Zn 0.01-0.045wt%, Cu 0.003-0.01wt%, Pb 0.01-0.05wt%, Sn 0.01-0.05wt%, Cr 0.01-0.05wt%, Ni 0.005-0.015wt%, RE 0.025-0.07wt%, Sr 0.007-0.025wt% and Al 91-93wt%;

[0009] The RE must contain Sc and also contains at least one selected from La and Ce.

[0010] According to the automobile wheel hub of the present invention, preferably, the content of RE is 0.03-0.065 wt %.

[0011] According to the automobile wheel hub of the present invention, preferably, the content of RE is 0.05-0.055 wt %.

[0012] According to the automobile wheel hub of the present invention, preferably, the content of Sc in the RE is 15-60wt%.

[0013] According to the automobile wheel hub of the present invention, preferably, the RE is selected from one of the following combinations:

[0014] (A) Sc and La;

[0015] (B) Sc and Ce.

[0016] According to the automobile wheel hub of the present invention, preferably, RE is combination (A), the content of Sc is 0.01 to 0.02 wt%, and the content of La is 0.01 to 0.045 wt%;

[0017] Or, RE is combination (B), the content of Sc is 0.01 to 0.02 wt%, and the content of Ce is 0.01 to 0.03 wt%.

[0018] According to the automobile wheel hub of the present invention, preferably, the secondary branch spacing of the automobile wheel hub is ≤26 μm.

[0019] According to the automobile wheel hub of the present invention, preferably, the automobile wheel hub has a tensile strength of ≥265 MPa, a yield strength of ≥180 MPa, and an elongation of ≥12.5%.

[0020] In another aspect, the present invention provides a method for preparing a vehicle wheel hub, comprising the following steps:

[0021] (1) providing an alloy liquid formed according to the composition of an automobile wheel hub;

[0022] (2) adding a rare earth aluminum alloy to the alloy liquid to obtain a first melt;

[0023] (3) adding an aluminum-strontium alloy and an aluminum-titanium-boron alloy to the first melt to obtain a second melt;

[0024] (4) casting the second melt to obtain a green body;

[0025] (5) The blank is heat treated to obtain an automobile wheel hub.

[0026] According to the preparation method of the present invention, preferably, in step (2), after the rare earth aluminum alloy is added, stirring is performed for 5 to 20 minutes, and then degassing is performed; after degassing, a refining agent is added to obtain a first melt;

[0027] In step (3), after the aluminum-strontium alloy and the aluminum-titanium-boron alloy are melted, they are stirred evenly; then the slag is removed to obtain a second melt;

[0028] In step (4), casting is carried out in a low pressure casting machine.

[0029] The automobile wheel hub of the present invention reduces the secondary branch spacing through the mutual cooperation between various elements. Furthermore, the automobile wheel hub of the present invention has higher tensile strength, yield strength and elongation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a schematic diagram of the shape of the test sample used for testing the mechanical properties of the automobile wheel hub in the present invention.

[0031] Figure 2 This is the metallographic structure diagram of the outer rim portion of the automobile wheel hub of Example 1.

[0032] Figure 3 This is the metallographic structure diagram of the outer rim portion of the automobile wheel hub of Example 2.

[0033] Figure 4 This is the metallographic structure diagram of the outer rim portion of the automobile wheel hub of Example 3.

[0034] The reference numerals are as follows:

[0035] 1-rod; 2-head; 3-cone; 31-cambered surface. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0037] <Car wheels>

[0038] The automobile wheel hub of the present invention comprises Si, Mg, Ti, Fe, Mn, P, Sb, Zn, Cu, Pb, Sn, Cr, Ni, RE, Sr and Al.

[0039] In the automobile wheel hub of the present invention, the content of Si is 6.8-7.5 wt %, preferably 7.0-7.2 wt %, and more preferably 7.0-7.1 wt %.

[0040] In the automobile wheel hub of the present invention, the content of Mg is 0.25-0.35wt%, preferably 0.3-0.33wt%, and more preferably 0.32-0.33wt%.

[0041] In the automobile wheel hub of the present invention, the content of Ti is 0.05-0.15wt%, preferably 0.1-0.13wt%, and more preferably 0.11-0.12wt%.

[0042] In the automobile wheel hub of the present invention, the content of Fe is 0.05-0.15wt%; preferably 0.08-0.12wt%; more preferably 0.09-0.1wt%.

[0043] In the automobile wheel hub of the present invention, the content of Mn is 0.01-0.05 wt %, preferably 0.02-0.04 wt %, and more preferably 0.02-0.03 wt %.

[0044] In the automobile wheel hub of the present invention, the content of P is 0.0005-0.003 wt %, preferably 0.001-0.0025 wt %, and more preferably 0.002-0.0022 wt %.

[0045] In the automobile wheel hub of the present invention, the content of Sb is 0.003-0.01%; preferably 0.005-0.008wt%; more preferably 0.006-0.007wt%.

[0046] In the automobile wheel hub of the present invention, the content of Zn is 0.01 to 0.045 wt %, preferably 0.015 to 0.035 wt %, and more preferably 0.025 to 0.03 wt %.

[0047] In the automobile wheel hub of the present invention, the content of Cu is 0.003-0.01 wt %, preferably 0.004-0.007 wt %, and more preferably 0.005-0.006 wt %.

[0048] In the automobile wheel hub of the present invention, the content of Pb is 0.01 to 0.05 wt %, preferably 0.02 to 0.04 wt %, and more preferably 0.03 to 0.035 wt %.

[0049] In the automobile wheel hub of the present invention, the content of Sn is 0.01 to 0.05 wt %, preferably 0.02 to 0.04 wt %, and more preferably 0.03 to 0.04 wt %.

[0050] In the automobile wheel hub of the present invention, the content of Cr is 0.01 to 0.05 wt %, preferably 0.02 to 0.04 wt %, and more preferably 0.02 to 0.03 wt %.

[0051] In the automobile wheel hub of the present invention, the content of Ni is 0.005-0.015wt%; preferably 0.007-0.012wt%; more preferably 0.009-0.01wt%.

[0052] In the automobile wheel hub of the present invention, the content of RE is 0.025-0.07 wt %; preferably 0.03-0.065 wt %; more preferably 0.05-0.052 wt %.

[0053] RE must contain Sc and at least one selected from La and Ce. Preferably, RE is selected from one of the following combinations: (A) Sc and La; (B) Sc and Ce. More preferably, RE is Sc and La.

[0054] The content of Sc in RE is 15 to 60 wt %, preferably 20 to 55 wt %, and more preferably 25 to 30 wt %.

[0055] In the automobile wheel hub of the present invention, the content of Sc may be 0.01 to 0.02 wt %, preferably 0.013 to 0.018 wt %, and more preferably 0.015 to 0.016 wt %.

[0056] In the automobile wheel hub of the present invention, the content of La may be 0.01 to 0.045 wt %, preferably 0.016 to 0.04 wt %, and more preferably 0.035 to 0.037 wt %.

[0057] In the automobile wheel hub of the present invention, the content of Ce may be 0.01 to 0.03 wt %, preferably 0.015 to 0.02 wt %, and more preferably 0.016 to 0.018 wt %.

[0058] In the automobile wheel hub of the present invention, the content of Sr is 0.007-0.025 wt %, preferably 0.01-0.02 wt %, and more preferably 0.012-0.015 wt %.

[0059] In the automobile wheel hub of the present invention, the content of Al is 91-93 wt %, preferably 91.5-92.5 wt %, and more preferably 92.0-92.2 wt %.

[0060] In the metallographic structure of the automobile wheel hub of the present invention, the secondary dendrite spacing is less than or equal to 26 μm; preferably, less than or equal to 25 μm. In some embodiments, the secondary dendrite spacing may be greater than or equal to 20 μm; or greater than or equal to 22 μm.

[0061] The tensile strength of the automobile wheel hub of the present invention is greater than or equal to 265 MPa, preferably greater than or equal to 270 MPa, and more preferably greater than or equal to 272 MPa. In some embodiments, the tensile strength may be less than or equal to 290 MPa, and may also be less than or equal to 280 MPa.

[0062] The yield strength of the automobile wheel hub of the present invention is greater than or equal to 180 MPa, preferably greater than or equal to 185 MPa, and more preferably greater than or equal to 188 MPa. In some embodiments, the tensile strength may be less than or equal to 195 MPa, and may also be less than or equal to 190 MPa.

[0063] The elongation of the automobile wheel hub of the present invention is greater than or equal to 12.5%, preferably greater than or equal to 13%. In some embodiments, the elongation may be less than or equal to 15%, or less than or equal to 14%.

[0064] The automobile wheel hub of the present invention has relatively high tensile strength, yield strength and elongation, and can meet the mechanical indicators of the automobile wheel hub.

[0065] <Method for preparing automobile wheel hub>

[0066] The method for preparing an automobile wheel hub of the present invention comprises the following steps: (1) providing alloy liquid; (2) preparing a first melt; (3) preparing a second melt; (4) casting; and (5) heat treatment.

[0067] Steps for providing alloy liquid

[0068] Provide alloy liquid formed according to the composition of the automobile wheel hub.

[0069] The raw materials may be melted to obtain alloy liquid. The composition of the raw materials may be configured according to the composition of the automobile wheel hub. The raw materials may include aluminum ingots, metallic silicon and magnesium ingots. The purity of the aluminum ingots may be greater than or equal to 99.5%; preferably, greater than or equal to 99.7%. The purity of the magnesium ingots may be greater than or equal to 99.5%; preferably, greater than or equal to 99.9%.

[0070] Steps for preparing the first melt

[0071] Rare earth aluminum alloy is added to the alloy liquid to obtain a first melt.

[0072] The rare earth elements in the rare earth aluminum alloy are determined according to the types of rare earth elements contained in the automobile wheel hub. The rare earth aluminum alloy can be selected from one or more of lanthanum aluminum alloy, cerium aluminum alloy, and scandium aluminum alloy. The content of rare earth elements in the rare earth aluminum alloy can be 1 to 15wt%. In some embodiments, the content of rare earth elements is 1.5 to 2.8wt%. In other embodiments, the content of rare earth elements is 9 to 11wt%.

[0073] In certain embodiments, a first rare earth aluminum alloy and a second rare earth aluminum alloy are added to the alloy liquid.

[0074] The first rare earth aluminum alloy is selected from lanthanum aluminum alloy and cerium aluminum alloy. The amount of the first rare earth aluminum alloy can be 0.1-0.5% of the mass of the alloy liquid, preferably 0.35-0.4%.

[0075] The second rare earth aluminum alloy is a scandium aluminum alloy. The amount of the second rare earth aluminum alloy used can be 0.5-1.0% of the mass of the alloy liquid, preferably 0.6-0.7%.

[0076] In certain embodiments, after the rare earth aluminum alloy is added, stirring is performed and then degassing is performed; after degassing, a refining agent is added to obtain a first melt.

[0077] The stirring time may be 5 to 20 minutes, preferably 10 to 15 minutes.

[0078] The refining agent may be A700-R refining agent. The amount of the refining agent used may be 0.1 to 0.8% of the mass of the alloy liquid, preferably 0.3 to 0.5%.

[0079] Steps for preparing the second melt

[0080] Aluminum-strontium alloy and aluminum-titanium-boron alloy are added to the first melt to obtain a second melt.

[0081] In the aluminum-strontium alloy, the content of strontium may be 5 to 15 wt %, preferably 10 to 12 wt %.

[0082] The amount of aluminum-strontium alloy used can be 0.1 to 0.25% of the mass of the alloy liquid; preferably 0.12 to 0.16%.

[0083] In the aluminum-titanium-boron alloy, the content of titanium may be 3-8 wt%, preferably 4-5 wt%, and the content of boron may be 0.2-1 wt%, preferably 0.5-0.8 wt%.

[0084] The amount of aluminum-titanium-boron alloy used can be 1 to 4% of the mass of the alloy liquid; preferably 2 to 2.5%.

[0085] In certain embodiments, after the aluminum-strontium alloy and the aluminum-titanium-boron alloy are melted, they are stirred evenly; then the slag is removed to obtain a second melt.

[0086] Casting steps

[0087] The second melt is cast to obtain a green body, which can be cast in a low-pressure casting machine.

[0088] The temperature of the second melt may be 650-750°C, preferably 690-700°C.

[0089] The low pressure casting mold may be preheated to 200-250°C; preferably 220-240°C.

[0090] The liquid raising pressure can be 0.01-0.05 MPa, preferably 0.02-0.03 MPa. The liquid raising speed can be 5-10 cm / s, preferably 6-8 cm / s. The liquid raising time can be 5-8 s.

[0091] Preferably, it is 6 to 7 seconds.

[0092] The filling pressure can be 0.05-0.09 MPa, preferably 0.06-0.08 MPa. The filling speed can be 3-10 cm / s, preferably 5-8 cm / s. The filling time can be 9-14 s.

[0093] Preferably, it is 10 to 12 seconds.

[0094] The holding pressure may be 0.09 to 0.12 MPa, preferably 0.10 to 0.11 MPa, and the holding time may be 60 to 100 s, preferably 80 to 90 s.

[0095] Heat treatment steps

[0096] The blank is heat treated to obtain the automobile wheel hub. Specifically, the blank is solution treated and then water quenched to obtain a solutionized blank. The solutionized blank is aged and cooled to obtain the automobile wheel hub.

[0097] The solution temperature may be 490 to 550° C., preferably 510 to 530° C. The solution time may be 3 to 12 hours, preferably 5 to 10 hours.

[0098] The water quenching can be carried out in hot water at a temperature of 50 to 90°C; preferably, the water quenching is carried out in hot water at a temperature of 60 to 80°C.

[0099] The aging temperature may be 100 to 150° C., preferably 120 to 140° C. The aging treatment time may be 1 to 6 hours, preferably 2 to 4 hours.

[0100] Cooling can be done by natural cooling.

[0101] Here is the test method:

[0102] The tensile strength, yield strength and elongation are tested according to the method specified in "GB / T228.1-2010 Tensile test of metallic materials Part 1: Room temperature test method".

[0103] The samples used are as follows Figure 1 As shown. The specimen is in the shape of a dumbbell, which has a rod 1 and two heads 2 connected to both ends of the rod 1. The rod 1 is connected to the two heads 2 through a truncated cone 3 respectively. The upper bottom surface of the truncated cone 3 is connected to the rod 1 and has the same diameter as the rod 1. The lower bottom surface of the truncated cone 3 is connected to the head 2 and has the same diameter as the head 2. The side surface of the truncated cone 3 is a concave arc surface 31. The length of the rod 1 is 27.5 mm and the diameter is 5±0.05 mm. The total length of the rod 1 and the two truncated cones 3 is 34 mm. The diameter of the head 2 is 9 mm. The total length of the specimen (the sum of the lengths of the rod 1, the two truncated cones 3 and the two heads 2) is 64 mm. The original gauge length L0 is 25 mm.

[0104] The specific test steps are as follows: For each type of automobile wheel hub, parallel samples are selected at least at six different locations for tensile testing. Before the test, the samples are first ground with 800﹟, 1000﹟, and 2000﹟ sandpaper in turn to ensure that the sample surface is smooth and free of foreign matter. The samples are tensile tested at room temperature using an INSTRON-5982 electronic universal testing machine, and the tensile rate is set to 1mm / min. Six samples are tested for each type of automobile wheel hub, and then the maximum and minimum values ​​are removed and the average value is taken.

[0105] The secondary dendrite spacing was tested using the following method: metallographic photographs were collected using a Zeiss Axioscope 5 optical microscope, and the secondary dendrite spacing was measured and averaged using metallographic analysis software.

[0106] The content of each element in the automobile wheel hub was tested using ICPS-8100 inductively coupled plasma spectrometer (ICP-AES).

[0107] Examples 1 to 3

[0108] The prepared raw materials are melted according to the composition of the automobile wheel hub to obtain alloy liquid. The raw materials include aluminum ingots with a purity of more than 99.7%, metal silicon and magnesium ingots with a purity of more than 99.9%.

[0109] The first rare earth aluminum alloy and the second rare earth aluminum alloy were added to the alloy liquid; after stirring for 10 minutes, degassing was performed, and then A-700R refining agent (purchased from Qingdao Fusai Ke Casting Materials Co., Ltd.) was sprinkled on the surface of the alloy liquid to obtain a first melt.

[0110] Aluminum strontium alloy (strontium content of 10wt%) and aluminum titanium boron alloy (titanium content of 5.0wt%, boron content of 0.6wt%) are added to the first melt. After the aluminum strontium alloy and the aluminum titanium boron alloy are melted, they are stirred evenly; then the scum on the surface is skimmed with a spoon to obtain a second melt.

[0111] The second melt at 700°C was cast using a low-pressure casting machine to obtain a green body. The specific process conditions are as follows: the mold is preheated to 230°C, the liquid rising pressure is 0.03MPa, the liquid rising speed is 7cm / s, and the liquid rising time is 6s; the filling pressure is 0.07MPa, the filling speed is 6cm / s, the filling time is 11s, the holding pressure is 0.10MPa, and the holding time is 80s.

[0112] The green body was solution treated at 520°C for 8 hours, and then quenched in hot water at 70°C to obtain a green body after solution treatment. The green body after solution treatment was aged at 130°C for 3 hours, and then naturally cooled to obtain an automobile wheel hub.

[0113] The specific parameters are shown in Table 1. The element composition of the obtained automobile wheel hub is shown in Table 2, and the tensile strength, yield strength, elongation and secondary branch spacing of the obtained automobile wheel hub are shown in Table 2.

[0114] Table 1

[0115]

[0116]

[0117] Comparative Example 1

[0118] Except that the first rare earth aluminum alloy and the second rare earth aluminum alloy are not added and the composition of the raw materials is adjusted according to the composition of the automobile wheel hub, the rest is the same as Example 1. The element composition of the obtained alloy is shown in Table 2, and the tensile strength, yield strength, elongation and secondary branch spacing of the obtained automobile wheel hub are also shown in Table 2.

[0119] Table 2

[0120] Example 1 Example 2 Example 3 Comparative Example 1 Si content (wt%) 7.2 7.0 7.1 7.0 Mg content (wt%) 0.30 0.33 0.31 0.33 Ti content (wt%) 0.1 0.12 0.12 0.1 Fe content (wt%) 0.10 0.09 0.08 0.085 Mn content (wt%) 0.03 0.02 0.03 0.03 P content (wt%) 0.001 0.002 0.0015 0.0015 Sb content (wt%) 0.008 0.006 0.007 0.007 Zn content (wt%) 0.020 0.030 0.017 0.017 Cu content (wt%) 0.005 0.005 0.005 0.005 Pb content (wt%) 0.03 0.03 0.02 0.02 Sn content (wt%) 0.02 0.03 0.03 0.03 Cr content (wt%) 0.03 0.02 0.03 0.03 Ni content (wt%) 0.009 0.009 0.009 0.009 La content (wt%) 0.018 0.037 -- -- Sc content (wt%) 0.016 0.015 0.018 -- Ce content (wt%) -- -- 0.016 -- Sr content (wt%) 0.014 0.015 0.015 0.014 Al content (wt%) 92.1 92.2 92.1 92.3 Tensile strength(MPa) 268.58 272.39 270.54 255.74 Yield strength(MPa) 184.08 188.96 183.10 172.5 Elongation(%) 12.5 13.0 12.6 12.3 Secondary dendrite spacing (μm) 25.94 24.47 25.32 27.73

[0121] The present invention is not limited to the above-mentioned embodiments. Without departing from the essential content of the present invention, any deformation, improvement and substitution that can be conceived by those skilled in the art shall fall within the scope of the present invention.

Claims

1. An automobile wheel hub, characterized in that: The automobile wheel hub comprises Si 6.8-7.5wt%, Mg 0.25-0.35wt%, Ti 0.05-0.15wt%, Fe 0.05-0.15wt%, Mn 0.01-0.05wt%, P 0.0005-0.003wt%, Sb 0.003-0.01wt%, Zn 0.01-0.045wt%, Cu 0.003-0.01wt%, Pb 0.01-0.05wt%, Sn 0.01-0.05wt%, Cr 0.01-0.05wt%, Ni 0.005-0.015wt%, RE 0.025-0.07wt%, Sr 0.007-0.025wt% and Al 91-93wt%; The RE must contain Sc and also contains at least one selected from La and Ce.

2. The automotive wheel hub according to claim 1, characterized in that: The content of RE is 0.03-0.065 wt%.

3. The automotive wheel hub according to claim 1, characterized in that: The content of RE is 0.05 to 0.055 wt%.

4. The automotive wheel hub according to claim 1, characterized in that: The content of Sc in the RE is 15-60 wt %.

5. The automotive wheel hub according to claim 1, characterized in that: The RE is selected from one of the following combinations: (A) Sc and La; (B) Sc and Ce.

6. The automotive wheel hub according to claim 5, characterized in that: RE is combination (A), Sc content is 0.01-0.02wt%, La content is 0.01-0.045wt%; Or, RE is combination (B), the content of Sc is 0.01 to 0.02 wt%, and the content of Ce is 0.01 to 0.03 wt%.

7. The automotive wheel hub according to claim 1, characterized in that: The secondary branch spacing of the automobile wheel hub is ≤26 μm.

8. The automotive wheel hub according to claim 1, characterized in that: The automobile wheel hub has a tensile strength of ≥265 MPa, a yield strength of ≥180 MPa, and an elongation of ≥12.5%.

9. The method for preparing an automobile wheel hub according to any one of claims 1 to 8, characterized in that: The steps include: (1) providing an alloy liquid formed according to the composition of an automobile wheel hub; (2) adding a rare earth aluminum alloy to the alloy liquid to obtain a first melt; (3) adding an aluminum-strontium alloy and an aluminum-titanium-boron alloy to the first melt to obtain a second melt; (4) casting the second melt to obtain a green body; (5) The blank is heat treated to obtain an automobile wheel hub.

10. The preparation method according to claim 9, characterized in that: In step (2), after the rare earth aluminum alloy is added, stirring is performed for 5 to 20 minutes, and then degassing is performed; after degassing, a refining agent is added to obtain a first melt; In step (3), after the aluminum-strontium alloy and the aluminum-titanium-boron alloy are melted, they are stirred evenly; then the slag is removed to obtain a second melt; In step (4), casting is carried out in a low pressure casting machine.

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