A 6000 series aluminum alloy medium and thick plate for spinning rim and preparation method thereof

Abstract

A 6000 series aluminum alloy medium and thick plate for spinning rims, the aluminum alloy raw material is composed of the following components in weight percentage: Si=0.45~0.75, Fe<0.65, Cu=0.25~0.35, Mn<0.10, Mg=0.95~1.15, Cr=0.15~0.30, Zn<0.20, Ti<0.10, the remainder is Al and inevitable impurities. The preparation process adopts precision heat treatment and rolling control technology to achieve the fine second phase and grain structure of aluminum from ingot to plate and strip. The finished aluminum alloy plate is 6~8mm thick, the grain size is ≤50μm, the second phase size is ≤10μm, the tensile strength is ≥100MPa, the yield strength is 35~90MPa, the elongation is ≥30%, and the rim surface prepared by spinning forming has no orange peel problem, which can better meet the technical requirements of aluminum for rims.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy materials, in particular to a 6000 series aluminum alloy medium and thick plate for spinning wheel rims and a preparation method thereof. Background Art

[0002] As the automobile industry develops towards environmental protection, comfort, safety and energy saving, the lightweight design of automobiles is particularly important. The most important thing in lightweighting automobiles is to reduce the weight of the "rim" of the hub to promote the aluminum alloying of automobile hubs. The hub consists of two parts: the rim and the spoke. Among them, the rim is produced by cold spinning process, the spoke is produced by low-pressure casting process, and the rim and the spoke are compounded into an ultra-light hub structure by stir friction welding.

[0003] With the development of the automobile industry and the improvement of consumers' requirements for driving comfort, aluminum alloys have gained popularity in the preparation of automobile wheels due to their unique properties. The advantages of aluminum alloy wheels are mainly as follows: (1) Fast heat dissipation: At room temperature, the thermal conductivity of aluminum alloy is three times that of steel, which can effectively prevent the wheels from overheating and causing tire blowouts at high speeds, greatly extending the service life of automobile and motorcycle tires, especially the life of high-load truck tires. (2) Light weight: The density of aluminum is lower than that of steel, and each aluminum alloy wheel can reduce the weight by about 2 kilograms. Because aluminum wheels are light and have a small moment of inertia, the acceleration of the car is improved, and the braking performance is also improved. While improving the acceleration ability of the car, it will also reduce fuel consumption; (3) Beautiful appearance. There are many different methods for treating the surface of aluminum alloys, which can show a beautiful metallic luster and enhance the technological and artistic sense of the wheel appearance.

[0004] Compared with the existing aluminum alloy wheel rim preparation technology (casting, forging, stamping), the wheel rim prepared by the spinning forming method has stable performance, low cost, and is easier to industrialize. The wheel hub production process is: aluminum plate → rolling → flattening → straight welding → flash removal → rounding → end cutting → flanging → roll forging → spinning → end cutting → compounding with die-cast wheel spokes → ring welding → milling thin surface in the machining workshop.

[0005] In the prior art, Al-Si-Mg aluminum alloys for casting include: ZL101, A356, German AlSi12Mg and Japanese AC4C; deformed aluminum includes 6063, 6061, 6082, 5052 and other aluminum alloy grades. This type of aluminum has medium strength and excellent processing and forming properties. With the continuous pursuit of lightweight automobiles, aluminum alloy sheets are required to be thinner, have higher strength, and better forming properties. When conventional 6000 series aluminum materials in the prior art are used to prepare rims, there is a high risk of cracking after spinning, a low yield rate, or the rim tensile performance does not meet the standards, the cost remains high, and it is difficult to promote and apply on a large scale. Therefore, it is urgent to develop the alloy composition and preparation process of 6000 series aluminum materials with higher comprehensive performance. Summary of the invention

[0006] The technical purpose of the present invention is to provide a 6000 series aluminum alloy medium and thick plate for spun rims with fine and uniform internal grain structure, high elongation, good tensile strength and excellent forming performance, and a preparation method thereof, so as to solve the technical problem that the strength and forming performance of conventional 6000 series aluminum alloys are difficult to simultaneously meet the requirements of spun rim preparation technology.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a 6000 series aluminum alloy medium and thick plate for spinning rims, the aluminum alloy raw material of the aluminum alloy medium and thick plate is composed of the following components in weight percentage: Si=0.45~0.75, Fe=0.05~0.65, Cu=0.25~0.35, Mn=0.04~0.10, Mg=0.95~1.15, Cr=0.15~0.30, Zn=0.01~0.2, Ti=0.02~0.10, and the balance is Al and unavoidable impurity elements.

[0008] Furthermore, the thickness of the aluminum alloy medium and thick plate is 6-8 mm, the tolerance is +0.28 / -0.02 mm, the grain size is ≤50 μm, the second phase size is ≤10 μm, the tensile strength is ≥100 MPa, the yield strength is 35-90 MPa, and the elongation is ≥30%.

[0009] A method for preparing a 6000 series aluminum alloy medium and thick plate for a spinning rim comprises the following steps:

[0010] Step S1, according to the above weight percentage ratio, weigh the components in the aluminum alloy raw material respectively, adopt the semi-continuous casting method, control the cooling water volume during the semi-continuous casting to be 155-162㎥ / h, and the water temperature cooling intensity to be 30.5-31.2° C., to obtain an aluminum alloy ingot for standby use;

[0011] Step S2, heat treating the aluminum alloy ingot obtained in step S1;

[0012] Step S3, hot rolling the aluminum alloy ingot after the heat treatment in step S2 to obtain a hot-rolled plate for standby use;

[0013] Step S4, cold rolling the hot-rolled plate obtained in step S3 for 1 to 3 passes to obtain a medium-thick plate with a thickness of 6 to 8 mm for standby use;

[0014] Step S5, annealing the medium and thick plate obtained in step S4 to obtain a finished aluminum alloy medium and thick plate.

[0015] Furthermore, in step S1, the melting temperature during the semi-continuous casting is 740-760°C, the casting temperature during the semi-continuous casting is 690-710°C, and the grain size from the core to the edge of the aluminum alloy ingot after the semi-continuous casting is 95-140 μm.

[0016] Furthermore, in step S2, the specific operation of the heat treatment is to place the aluminum alloy ingot in a temperature environment of 560-570°C for soaking treatment for 8-18 hours, and then naturally cool it to room temperature.

[0017] Furthermore, in step S3, the specific operation of the hot rolling treatment is to place the aluminum alloy ingot in a temperature environment of 490-520°C for heating treatment for 11-15 hours, and then control the starting rolling temperature to 450-500°C and the final rolling temperature to ≥350°C to obtain a hot-rolled plate with a final rolling thickness of 8-10 mm.

[0018] Furthermore, in step S5, the annealing temperature during the annealing treatment is ≥320°C.

[0019] Beneficial effects of the present invention:

[0020] 1. The 6000 series aluminum alloy medium and thick plate for spinning rims of the present invention is made by adding alloy elements such as Cu, Mn, Cr, Zn, Ti and Fe to Al-Si-Mg alloy. Among them, the addition of Fe and Cu elements can effectively improve the strength of the alloy, especially the specific mass percentage of the metal element Cu = 0.25~0.35 in the alloy is an important means to adjust the strength of the finished rim, so that the plasticity and fatigue resistance of the rim are significantly enhanced; the addition of Ti element can refine the original grains, and the control of the addition amount of the alloy elements Mn, Cr and Zn ensures that the tensile strength and forming performance of the aluminum alloy material in the O treatment state and the T6 treatment state can meet the technical requirements of aluminum for spinning rims. In addition, during the processing of the aluminum alloy, various alloy compounds can be formed between the alloying elements, such as Cu2Mg formed between Cu and Mg; TiAl3 generated by the peritectic reaction of Ti in Al, etc. Under the control of specific process parameters, the surfaces where these alloy compounds contact the liquid metal can become effective nucleation base surfaces during aluminum solidification, thereby increasing the nucleation rate of the aluminum alloy, thereby refining the crystal structure, and significantly improving the strength of the alloy. At the same time, the elongation, tensile strength, etc. are also greatly improved.

[0021] 2. The 6000 series aluminum alloy medium and thick plate for spinning rims of the present invention limits the composition of the alloy and the mass percentage ratio of each component, so that the components are reasonably compatible, have a comprehensive effect, and have mutual alloying effect, thereby significantly improving the comprehensive performance of the Al-Si-Mg alloy material. In terms of preparation technology, by precisely controlling the casting heat treatment, hot rolling and annealing process parameters, a cold rolling process is added to achieve the refinement of the second phase and grain structure of the aluminum material from the ingot to the plate strip. The prepared aluminum alloy medium and thick plate has a small grain size, high tensile strength, excellent forming performance, good version, and small thickness tolerance. The thickness of the finished aluminum plate is 6~8mm, the grain size is ≤50μm, the second phase size is ≤10μm, the tensile strength is ≥100MPa, the yield strength is 35~90MPa, and the elongation is ≥30%. The rim surface prepared by spinning using the aluminum alloy medium and thick plate of the present invention as the raw material has no orange peel problem, excellent comprehensive performance, and better meets the technical requirements of aluminum alloy for rims.

[0022] 3. In the preparation process of a 6000 series aluminum alloy medium and thick plate for a spun wheel rim of the present invention, the cooling water volume during casting is regulated to be 155-162㎥ / h and the water temperature cooling intensity is 30.5-31.2°C in the semi-continuous casting step; in the hot rolling step, a large amount of rolling reduction is performed to dynamically recrystallize the grains and obtain a finished aluminum alloy with fine and uniform grain structure, thereby ensuring that the finished aluminum alloy can meet the technical requirements of aluminum alloy for spun wheel hubs in subsequent spinning forming, stir friction welding and surface treatment processes.

[0023] 4. The preparation process of a 6000 series aluminum alloy medium and thick plate for a spun wheel rim of the present invention adds a cold rolling process after the hot rolling treatment, and the obtained hot-rolled plate is cold-rolled for 1 to 3 times. The purpose is to further break up the hot-rolled structure grains through multiple cold rolling treatments, so that the alloy grains are fibrous, thereby improving its elongation and tensile strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a grain morphology diagram of the edge of the aluminum alloy ingot in Example 1;

[0025] Figure 2 is a grain morphology diagram of the core of the aluminum alloy ingot in Example 1;

[0026] Figure 3 is the second phase morphology of the aluminum alloy ingot before heat treatment in Example 1;

[0027] Figure 4 is a second phase morphology diagram of the aluminum alloy ingot after heat treatment in Example 1;

[0028] Figure 5 is the second phase morphology of the medium and thick plate obtained after cold rolling in Example 1;

[0029] Figure 6 is a grain morphology diagram of the finished aluminum alloy medium and thick plate obtained in Example 1;

[0030] Figure 7 This is the second phase morphology of the hot-rolled plate obtained in Comparative Example 1;

[0031] Figure 8 This is a grain morphology diagram of the finished aluminum alloy medium and thick plate prepared in Example 1. DETAILED DESCRIPTION

[0032] The following examples are only used to further illustrate the present invention, but do not constitute any limitation to the present invention.

[0033] A 6000 series aluminum alloy medium and thick plate for spinning wheel rims, wherein the aluminum alloy raw material of the aluminum alloy medium and thick plate is composed of the following components in weight percentage: main alloying elements Si=0.45~0.75, Mg=0.95~1.15; trace alloying elements Cu=0.25~0.35, Mn=0.04~0.10, Cr=0.15~0.30, Zn=0.01~0.2, Ti=0.02~0.10, and the Fe element content is controlled to be 0.05~0.65, and the balance is Al and unavoidable impurity elements. The aluminum alloy medium and thick plate has a thickness of 6~8mm, a tolerance of +0.28 / -0.02mm, a grain size of ≤50μm, a second phase size of ≤10μm, a tensile strength of ≥100MPa, a yield strength of 35~90MPa, and an elongation of ≥30%.

[0034] The method for preparing the 6000 series aluminum alloy medium and thick plate for the spinning rim specifically comprises the following steps:

[0035] Step S1, according to the above weight percentage ratio, weigh each component in the aluminum alloy raw material respectively, adopt a semi-continuous casting method, control the melting temperature during semi-continuous casting to be 740-760° C., the casting temperature to be 690-710° C., the cooling water volume to be 155-162㎥ / h, and the water temperature cooling intensity to be 30.5-31.2° C., and obtain an aluminum alloy ingot with a core-to-edge grain size of 95-140μm, which is set aside;

[0036] Step S2, placing the aluminum alloy ingot obtained in step S1 in an environment with a temperature of 560-570° C. for soaking treatment for 8-18 hours, and then naturally cooling to room temperature in air, so that the second phase in the aluminum alloy ingot is intermittently distributed along the grain boundaries;

[0037] Step S3, hot rolling the aluminum alloy ingot after the heat treatment in step S2, placing the aluminum alloy ingot in a temperature environment of 490-520° C. for heating treatment for 11-15 hours, then controlling the starting rolling temperature to be 450-500° C. and the final rolling temperature to be ≥350° C., to obtain a hot-rolled plate with a final rolling thickness of 8-10 mm for standby use;

[0038] Step S4, cold rolling the hot-rolled plate obtained in step S3 for 1 to 3 passes to obtain a medium-thick plate with a thickness of 6 to 8 mm for standby use;

[0039] Step S5, performing annealing treatment at ≥320°C on the medium and thick plates obtained in step S4, so as to obtain finished aluminum alloy medium and thick plates.

[0040] The 6000 series aluminum alloy medium and thick plate for spinning wheel rims of the present invention solves the problem that the strength and forming performance of conventional 6000 series aluminum materials are difficult to simultaneously meet the technical requirements of spinning wheel rims. The preparation process controls the casting, hot rolling and annealing process parameters, and adds a cold rolling process. The prepared aluminum alloy medium and thick plate has a fine grain size, high tensile strength, excellent forming performance, good version, and small thickness tolerance, which meets the technical requirements of aluminum alloy for spinning wheel rims.

[0041] Example 1

[0042] A 6000 series aluminum alloy medium and thick plate for a spinning rim, wherein the raw material of the plate consists of the following components in weight percentage: Si=0.6, Fe=0.5, Cu=0.28, Mn=0.1, Mg=1.05, Cr=0.2, Zn=0.15, Ti=0.10, and the remainder of Al and inevitable impurities.

[0043] The specific preparation method comprises the following steps:

[0044] Step S1, respectively weigh the components of the aluminum alloy raw material in the above weight percentage ratio, and then adopt a semi-continuous casting method, control the melting temperature during semi-continuous casting to 750°C, the casting temperature to 700°C, the cooling water volume to 160㎥ / h, and the water temperature cooling intensity to 30.7°C, to obtain a flat aluminum alloy ingot with a core-to-edge grain size of 98-130μm, and its specific grain morphology is as shown in the attached Figure 1 and attached Figure 2 As shown;

[0045] Step S2, placing the aluminum alloy ingot obtained in step S1 in an environment with a temperature of 560°C for soaking treatment for 12 hours, and then naturally cooling to room temperature. The second phase in the aluminum alloy ingot changes from continuous distribution to discontinuous distribution. The second phase morphology of the aluminum alloy ingot before and after heat treatment is shown in the attached figure. Figure 3 and attached Figure 4 As shown;

[0046] Step S3, hot rolling the aluminum alloy ingot after the heat treatment in step S2, placing the aluminum alloy ingot in a temperature environment of 490° C. for heating treatment for 12 hours, then controlling the starting rolling temperature to be 490° C. and the final rolling temperature to be 350° C., and rolling the flat aluminum alloy ingot with a thickness of 560 mm for 23 passes to obtain a hot-rolled plate with a final rolling thickness of 10 mm for standby use;

[0047] Step S4: cold rolling the hot-rolled plate obtained in step S3 for two passes to obtain a medium-thick plate with a thickness of 8 mm. Figure 5 As shown, the size of the second phase in the medium and thick plate is small;

[0048] Step S5: annealing the medium and thick plate obtained in step S4 at 330°C. Figure 6 As shown, the finished aluminum alloy medium and thick plate with fine grain size is obtained.

[0049] The aluminum alloy medium and thick plate prepared in this embodiment has a thickness of 8 mm and a tolerance of +0.03 mm. The alloy performance measurement shows that the tensile strength of the annealed state is 119 MPa, the yield strength is 70 MPa, the elongation is 31%, and the grain size is small, which can better meet the technical requirements of high-strength aluminum alloy medium and thick plates for spinning rims.

[0050] Example 2

[0051] A 6000 series aluminum alloy medium and thick plate for a spinning rim, wherein the raw material of the plate consists of the following components in weight percentage: Si=0.5, Fe=0.3, Cu=0.31, Mn=0.04, Mg=0.95, Cr=0.15, Zn=0.01, Ti=0.03, and the remainder of Al and inevitable impurities.

[0052] The specific preparation method comprises the following steps:

[0053] Step S1, respectively weighing the components of the aluminum alloy raw material in the above weight percentage ratio, and then adopting a semi-continuous casting method, controlling the melting temperature during semi-continuous casting to be 740° C., the casting temperature to be 710° C., the cooling water volume to be 155㎥ / h, and the water temperature cooling intensity to be 31° C., to obtain a flat aluminum alloy ingot with a core-to-edge grain size of 100-126μm, and set aside;

[0054] Step S2, placing the aluminum alloy ingot obtained in step S1 in an environment with a temperature of 570° C. for soaking treatment for 8 hours, and then naturally cooling to room temperature in air, so that the second phase in the aluminum alloy ingot changes from continuous distribution to discontinuous distribution;

[0055] Step S3, hot rolling the aluminum alloy ingot after the heat treatment in step S2, placing the aluminum alloy ingot in a temperature environment of 500° C. for heating treatment for 13 hours, then controlling the starting rolling temperature to 470° C. and the final rolling temperature to 360° C. After the flat aluminum alloy ingot is rolled for 20 times, a hot-rolled plate with a final rolling thickness of 10 mm is obtained for standby use;

[0056] Step S4, cold rolling the hot-rolled plate obtained in step S3 for two passes to obtain a medium-thick plate with a thickness of 8 mm for standby use;

[0057] Step S5, subjecting the medium and thick plates obtained in step S4 to annealing at 330°C to obtain finished aluminum alloy medium and thick plates.

[0058] The aluminum alloy medium and thick plate prepared in this embodiment has a thickness of 8 mm and a tolerance of +0.07 mm. The alloy performance measurement shows that the tensile strength of the annealed state is 110 MPa, the yield strength is 52 MPa, the elongation is 30%, and the grain size is small, which can better meet the technical requirements of high-strength aluminum alloy medium and thick plates for spinning rims.

[0059] Example 3

[0060] A 6000 series aluminum alloy medium and thick plate for a spinning rim, wherein the raw material of the plate consists of the following components in weight percentage: Si=0.45, Fe=0.65, Cu=0.25, Mn=0.07, Mg=1.00, Cr=0.25, Zn=0.18, Ti=0.02, and the remainder of Al and inevitable impurities.

[0061] The specific preparation method comprises the following steps:

[0062] Step S1, respectively weighing the components of the aluminum alloy raw material in the above weight percentage ratio, and then adopting a semi-continuous casting method, controlling the melting temperature during semi-continuous casting to be 740-760° C., the casting temperature to be 690° C., the cooling water volume to be 162㎥ / h, and the water temperature cooling intensity to be 31.2° C., to obtain a flat aluminum alloy ingot with a core-to-edge grain size of 97-135μm, and set aside;

[0063] Step S2, placing the aluminum alloy ingot obtained in step S1 in an environment with a temperature of 565° C. for soaking treatment for 10 hours, and then naturally cooling to room temperature in air, so that the second phase in the aluminum alloy ingot changes from continuous distribution to discontinuous distribution;

[0064] Step S3, hot rolling the aluminum alloy ingot after the heat treatment in step S2, placing the aluminum alloy ingot in a temperature environment of 510° C. for heating treatment for 15 hours, then controlling the starting rolling temperature to 450° C. and the final rolling temperature to 370° C. After 25 passes of rolling, the flat aluminum alloy ingot is obtained to obtain a hot-rolled plate with a final rolling thickness of 8 mm for standby use;

[0065] Step S4, cold rolling the hot-rolled plate obtained in step S3 for three passes to obtain a medium-thick plate with a thickness of 6 mm for standby use;

[0066] Step S5, subjecting the medium and thick plates obtained in step S4 to annealing at 320°C to obtain finished aluminum alloy medium and thick plates.

[0067] The aluminum alloy medium and thick plate prepared in this embodiment has a thickness of 6 mm and a tolerance of +0.02 mm. The alloy performance measurement shows that the tensile strength of the annealed state is 152 MPa, the yield strength is 71 MPa, the elongation is 35%, and the grain size is small, which can better meet the technical requirements of high-strength aluminum alloy medium and thick plates for spinning rims.

[0068] Example 4

[0069] A 6000 series aluminum alloy medium and thick plate for a spinning rim, wherein the raw material of the plate consists of the following components in weight percentage: Si=0.75, Fe=0.05, Cu=0.35, Mn=0.09, Mg=1.15, Cr=0.30, Zn=0.2, Ti=0.08, and the remainder of Al and inevitable impurities.

[0070] The specific preparation method comprises the following steps:

[0071] Step S1, respectively weighing the components of the aluminum alloy raw material in the above weight percentage ratio, and then adopting a semi-continuous casting method, controlling the melting temperature during semi-continuous casting to 760° C., the casting temperature to 705° C., the cooling water volume to 158㎥ / h, and the water temperature cooling intensity to 30.5° C., to obtain a flat aluminum alloy ingot with a core-to-edge grain size of 99-138μm, and set it aside;

[0072] Step S2, placing the aluminum alloy ingot obtained in step S1 in an environment with a temperature of 570° C. for soaking treatment for 11 hours, and then naturally cooling to room temperature in air, so that the second phase in the aluminum alloy ingot changes from continuous distribution to discontinuous distribution;

[0073] Step S3, hot rolling the aluminum alloy ingot after the heat treatment in step S2, placing the aluminum alloy ingot in a temperature environment of 520° C. for heating treatment for 11 hours, then controlling the starting rolling temperature to 500° C. and the final rolling temperature to 350° C., and after the flat aluminum alloy ingot is rolled for 22 passes, a hot-rolled plate with a final rolling thickness of 9 mm is obtained for standby use;

[0074] Step S4, cold rolling the hot-rolled plate obtained in step S3 for three passes to obtain a medium-thick plate with a thickness of 7 mm for standby use;

[0075] Step S5, subjecting the medium and thick plates obtained in step S4 to annealing at 350°C to obtain finished aluminum alloy medium and thick plates.

[0076] The aluminum alloy medium and thick plate prepared in this embodiment has a thickness of 7 mm and a tolerance of +0.05 mm. The alloy performance measurement shows that the tensile strength of the annealed state is 139 MPa, the yield strength is 83 MPa, the elongation is 33%, and the grain size is small, which can better meet the technical requirements of high-strength aluminum alloy medium and thick plates for spinning rims.

[0077] Comparative Example 1

[0078] A 6000 series aluminum alloy medium and thick plate for a spun rim, the alloy composition of the raw material is the same as that of Example 1.

[0079] The specific preparation method comprises the following steps:

[0080] Step S1, respectively weighing the components of the aluminum alloy raw material in the above weight percentage ratio, and then, using a smelting and semi-continuous casting method to obtain a flat aluminum alloy ingot for standby use;

[0081] Step S2, placing the aluminum alloy ingot obtained in step S1 in an environment with a temperature of 560° C. for soaking treatment for 12 hours, and then naturally cooling to room temperature in air;

[0082] Step S3, hot rolling the aluminum alloy ingot after the heat treatment in step S2, placing the aluminum alloy ingot in a temperature environment of 490°C for heating treatment for 12 hours, then controlling the starting rolling temperature to 490°C and the final rolling temperature to 330°C to obtain a hot rolled plate with a final rolling thickness of 8 mm. The morphology of the hot rolled plate obtained in this embodiment is as shown in the attached figure. Figure 7 As shown in the attached Figure 7 It can be seen that the second phase of the alloy is small in size but unevenly distributed;

[0083] Step S4: annealing treatment, controlling the annealing temperature to 360°C. Figure 8 As shown, the finished aluminum alloy medium and thick plate with coarse grain size is obtained.

[0084] The aluminum alloy medium and thick plate prepared in this embodiment has a thickness of 8 mm and a tolerance of +0.24 mm. The alloy performance measurement shows that the tensile strength of the annealed plate is 96 MPa, the yield strength is 34 MPa, and the elongation is 21%. In addition, the grain size is coarse, which cannot meet the technical requirements of high-strength aluminum alloy medium and thick plates for spinning hubs.

Claims

1. A 6000 series aluminum alloy medium and thick plate for spinning rims, characterized in that: The aluminum alloy raw material of the aluminum alloy medium and thick plate is composed of the following components in weight percentage: Si=0.45~0.75, Fe=0.05~0.65, Cu=0.25~0.35, Mn=0.04~0.10, Mg=0.95~1.15, Cr=0.15~0.30, Zn=0.01~0.2, Ti=0.02~0.10, and the balance is Al and unavoidable impurity elements; The method for preparing the 6000 series aluminum alloy medium and thick plate for the spinning rim specifically comprises the following steps: Step S1: weigh the components in the aluminum alloy raw material according to the above weight percentage ratio, adopt a semi-continuous casting method, and control the cooling water volume during the semi-continuous casting to be 155-162 m 3 / h, the water temperature cooling intensity is 30.5-31.2°C, and the size of the grains from the core to the edge of the aluminum alloy ingot after semi-continuous casting is 95-140μm, and the aluminum alloy ingot is obtained for standby use; Step S2, heat treating the aluminum alloy ingot obtained in step S1; Step S3, hot rolling the aluminum alloy ingot after the heat treatment in step S2 to obtain a hot-rolled plate for standby use; Step S4, cold rolling the hot-rolled plate obtained in step S3 for 1 to 3 passes to obtain a medium-thick plate with a thickness of 6 to 8 mm for standby use; Step S5, annealing the medium and thick plate obtained in step S4 to obtain a finished aluminum alloy medium and thick plate, wherein the finished aluminum alloy medium and thick plate has a thickness of 6 to 8 mm, a tolerance of -0.02 to +0.28 mm, a grain size of ≤50 μm, a second phase size of ≤10 μm, a tensile strength of ≥100 MPa, a yield strength of 35 to 90 MPa, and an elongation of ≥30%.

2. The 6000 series aluminum alloy medium and thick plate for spinning wheel rim according to claim 1, characterized in that: In step S1, the melting temperature during the semi-continuous casting is 740-760°C, and the casting temperature during the semi-continuous casting is 690-710°C.

3. The 6000 series aluminum alloy medium and thick plate for spinning wheel rim according to claim 1, characterized in that: In step S2, the specific operation of the heat treatment is to place the aluminum alloy ingot in a temperature environment of 560-570°C for soaking treatment for 8-18 hours, and then naturally cool it to room temperature.

4. The 6000 series aluminum alloy medium and thick plate for spinning wheel rim according to claim 1, characterized in that: In step S3, the specific operation during hot rolling is to place the aluminum alloy ingot in a temperature environment of 490-520°C for heating treatment for 11-15 hours, and then control the starting rolling temperature to 450-500°C and the final rolling temperature to ≥350°C to obtain a hot-rolled plate with a final rolling thickness of 8-10 mm.

5. The 6000 series aluminum alloy medium and thick plate for spinning wheel rim according to claim 1, characterized in that: In step S5, the annealing temperature during the annealing treatment is ≥ 320°C.

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