Mechanical disc and preparation method thereof

Abstract

The invention discloses a mechanical disc and a preparation method thereof, and belongs to the technical field of aluminum alloy. Comprising the following steps: casting ingredients according to element proportions to obtain cast ingots; the aluminum alloy comprises the following components in percentage by weight: 0.01 to 0.03 percent of Si, 0.01 to 0.25 percent of Fe, 2.5 to 5.5 percent of Mg, 0.1 to 0.5 percent of Zn, 0.001 to 0.01 percent of Ti and the balance of aluminum. The ratio of Mg to Si is 200-400; casting ingot hot rolling; the initial rolling temperature is 480-500 DEG C, and the final rolling temperature is greater than or Cold-rolling the hot-rolled plate; sequentially straightening, annealing and cutting the cold-rolled sheet to obtain a strip material; the annealing temperature is 280-350 DEG C, and the time is 10-13 hours; stamping and annealing the strip material in sequence to obtain a mechanical disc; the die gap is 5-8% of the plate thickness; and annealing at 360-380 DEG C for 1-2 hours. According to the mechanical disc, the warping degree is smaller than or equal to 0.01 mm / m, the springback value is smaller than or equal to 0.1%, the residual stress is smaller than or equal to 75 MPa, and the forming precision and the qualification rate of the disc are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum alloy, in particular to a mechanical disc and a preparation method thereof. BACKGROUND

[0002] In the precision machinery manufacturing industry, especially in the production field of mechanical discs, aluminum alloy plates as key raw materials directly determine the precision and reliability of the final products. However, for a long time, the composition design and manufacturing process of traditional aluminum alloy plates have been facing a series of challenges, which not only restrict the manufacturing precision of mechanical discs, but also affect their performance in high-load and high-precision application scenarios, becoming a bottleneck for the development of the industry.

[0003] Traditional aluminum alloy plates often have problems such as high plate warping degree and large stamping springback due to unreasonable composition design (such as unreasonable Zn content easily causing intergranular corrosion, and unbalanced Fe / Si ratio leading to stamping cracks) and insufficient process control (such as grain orientation disorder caused by direct aging treatment after cold rolling, and insufficient residual stress elimination caused by annealing temperature fluctuation), which seriously affect the subsequent processing qualification rate. However, the existing technology is difficult to achieve precise control of the stamping deformation amount. SUMMARY

[0004] The main purpose of the present application is to provide a mechanical disc and a preparation method thereof to solve the problem of low forming precision of aluminum alloy mechanical discs in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a preparation method of a mechanical disc is provided, comprising:

[0006] Step S1: dosing and casting according to the proportion of each element of aluminum alloy to obtain an ingot; wherein, in terms of weight percentage, the proportion of each element includes: Si 0.01-0.03%, Fe 0.01-0.25%, Mg 2.5-5.5%, Zn 0.1-0.5%, Ti 0.001-0.01%, the balance being aluminum and unavoidable impurities; total 100%; the weight ratio of Mg and Si is 200-400;

[0007] Step S2: hot rolling the ingot to obtain a hot rolled plate; wherein, the opening rolling temperature is 480-500℃, and the final rolling temperature is ≥300℃;

[0008] Step S3: cold rolling the hot rolled plate to obtain a cold rolled plate;

[0009] Step S4: sequentially straightening, stabilizing annealing and cutting the cold rolled plate to obtain a strip; wherein, the stabilizing annealing conditions include: annealing temperature 280-350℃, annealing time 10-13h;

[0010] Step S5: sequentially stamping and flattening annealing the strip to obtain the mechanical disc; wherein the dynamic adjustment clearance of the die during stamping is 5-8% of the thickness of the strip; and the flattening annealing is performed under the conditions of an annealing temperature of 360-380 DEG C and an annealing time of 1-2 h.

[0011] Further, in step S2, the final rolling temperature of the hot rolling is 300-350 DEG C.

[0012] Further, the total reduction rate of the hot rolling is 98-99.5%.

[0013] Further, the thickness of the hot rolled plate is 2-6 mm.

[0014] Further, the single-pass reduction rate of the hot rolling is first increased and then decreased.

[0015] Further, the hot rolling is performed for 20-25 passes with a single-pass reduction rate of 1-40%.

[0016] Further, in step S3, the hot rolled plate is air-cooled to below 100 DEG C and then cold rolled.

[0017] Further, the total reduction rate of the cold rolling is 70-95% and the cold rolling is performed for 1-4 passes.

[0018] Further, in step S3, the total reduction rate of the cold rolling is 75-85% and the cold rolling is performed for 1-2 passes.

[0019] Further, the thickness of the cold rolled plate is 0.5-1.5 mm.

[0020] Further, in step S4, the deformation rate of the straightening is 1-3%.

[0021] Further, the straightening sequentially comprises rough straightening, fine straightening and sizing.

[0022] Further, the stabilization annealing is performed in an air furnace.

[0023] Further, the anisotropy index of the strip is Δr≤0.1.

[0024] Further, in step S5, the die dynamic compensation coefficient K during stamping is 1.05-1.12.

[0025] Further, in step S5, the stamping sequentially comprises preforming, fine stamping and sizing.

[0026] Further, the flattening annealing is performed in a non-reactive atmosphere.

[0027] Further, after step S5, step S6 is further included, comprising: naturally cooling the mechanical disc to 5-45 DEG C.

[0028] According to a second aspect of the present application, a mechanical disc is provided, which is prepared by the preparation method of the mechanical disc.

[0029] Further, the mechanical disc has a warpage of ≤0.01 mm / m, a springback of ≤1.0‰, and a residual stress of ≤75 MPa; the mechanical disc has a grain length of 22-34 μm and an equiaxed grain morphology.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The present application optimizes the element ratio of the aluminum alloy disc, first, makes the strength and corrosion resistance of the aluminum alloy material achieve the best balance, reduces the tendency of cracks in the material during the preparation of the disc; and then optimizes the disc preparation process, such as the ingot is sequentially subjected to hot rolling, cold rolling, straightening, stabilization annealing, sectioning, punching, and flat annealing, and the process parameters in each process are optimized, so that the aluminum alloy material and the process parameters are more suitable; the element ratio and the process parameters in each stage achieve the best synergistic effect, so that the warpage of the finally prepared mechanical disc is reduced to below 0.01 mm / m, the springback is controlled to be below 1.0‰, the residual stress is reduced to below 75 MPa, and the forming precision and the qualification rate of the aluminum alloy mechanical disc are greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0032] The drawings accompanying the specification of the present application form a part thereof, serve to provide further understanding of the present application, and together with the specification explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0033] Figure 1 is a processing flow chart of the aluminum alloy mechanical disc provided by the embodiment 1 of the present application;

[0034] Figure 2 is an optical metallographic microscope graph of the mechanical disc prepared by the embodiment 1 of the present application. DETAILED DESCRIPTION

[0035] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0036] The traditional aluminum alloy plate has unreasonable component design (such as high Zn content which easily causes intergranular corrosion, and unbalanced Fe / Si ratio which causes stamping cracks) and insufficient process control (such as direct aging treatment after cold rolling which causes grain orientation disorder, and annealing temperature fluctuation which causes insufficient residual stress elimination), and problems such as high disc warpage and large stamping springback often occur, which seriously affects the subsequent processing qualification rate.

[0037] According to a first aspect of the present application, a method for preparing a mechanical disc piece is provided, as shown in the following steps: Figure 1

[0038] Step S1: ingredients are prepared according to the proportion of each element in the aluminum alloy, and then cast to obtain an ingot; wherein the proportion of each element includes: Si 0.01-0.03%, Fe 0.01-0.25%, Mg 2.5-5.5%, Zn 0.1-0.5%, Ti 0.001-0.01%, the balance being aluminum and unavoidable impurities; the total is 100%; the weight ratio of Mg and Si is 200-400;

[0039] Step S2: hot rolling the ingot to obtain a hot-rolled plate; wherein the open rolling temperature is 480-500℃, and the final rolling temperature is ≥300℃;

[0040] Step S3: cold rolling the hot-rolled plate to obtain a cold-rolled plate;

[0041] Step S4: the cold-rolled plate is sequentially straightened, stabilized annealed and cut into strips to obtain a strip; wherein the conditions of the stabilization annealing include: annealing temperature is 280-350℃, and annealing time is 10-13h;

[0042] Step S5: the strip is sequentially punched and flat annealed to obtain a mechanical disc piece; wherein the dynamic adjustment gap of the die during punching is 5-8% of the plate thickness; the conditions of the flat annealing include: annealing temperature is 360-380℃, and annealing time is 1-2h.

[0043] ​The application firstly optimizes the properties of raw materials to balance the material strength and corrosion resistance, and reduce the crack tendency during subsequent processing of the materials. For example, in the aluminum alloy material, the proportion of Si element is any value or a range value between any two of 0.01%, 0.015%, 0.02%, 0.025% and 0.03%; the proportion of Fe element is any value or a range value between any two of 0.01%, 0.05%, 0.10%, 0.15%, 0.20% and 0.25%; the proportion of Mg element is any value or a range value between any two of 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0% and 5.5%; the proportion of Zn element is any value or a range value between any two of 0.1%, 0.2%, 0.3%, 0.4% and 0.5%; the proportion of Ti element is any value or a range value between any two of 0.001%, 0.005% and 0.01%; especially, the weight ratio of Mg and Si is controlled to be any value or a range value between any two of 200, 220, 250, 280, 300, 320, 350, 380 and 400, and the content of Fe is strictly controlled to be 0.01-0.25; under the overall proportion, the excessive Si can be avoided to form free brittle phase, and the residual stress is reduced; secondly, the disc process is optimized to make the raw material properties and the process more matched to achieve the best synergistic effect.For example, the hot rolling starting temperature is controlled at any value among 480℃, 485℃, 490℃, 495℃, 500℃ or a range value between any two of them; the finishing temperature is 300-350℃, further 300-330℃; the above hot rolling temperature and finishing temperature are more suitable for the aluminum alloy material with the above element ratio, at which the grains in the aluminum alloy have high plasticity, can better cope with the large deformation in the hot rolling process, prevent the generation of material cracks, and at which the recrystallization process can also be promoted, which helps to eliminate the work hardening generated in the subsequent cold working process, form a more uniform grain structure, and improve the isotropy and plasticity of the material; at the hot rolling temperature, the grain orientation more conducive to subsequent processing can be formed; as the temperature decreases to the above finishing temperature, the grain size is effectively controlled, avoiding abnormal grain growth caused by too fast cooling speed, ensuring the optimization of the microstructure of the plate, thereby improving the mechanical properties and processing performance of the plate; hot rolling at the above starting temperature range helps to reduce the internal residual stress of the material, high temperature can promote the diffusion and uniform distribution of the metal alloy, reduce grain boundary segregation and reduce the risk of intergranular corrosion; at the same time, at the above suitable starting temperature, the flowability and formability of the aluminum alloy material are improved, so that the plate can pass through the roller more smoothly in the hot rolling process, reducing surface defects such as cracks, wrinkles, etc.; and by hot rolling at a higher starting temperature and a moderate finishing temperature, the grain morphology and size can be controlled to form an ideal microstructure, and the uniformity and fineness of the grains help to improve the strength and plasticity of the material, while having a positive impact on the subsequent cold working and annealing process. For example, the annealing temperature after cold rolling is controlled at any value among 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, 350℃ or a range value between any two of them; the annealing time is 10h, 11h, 12h, 13h. Annealing the cold rolled plate at the above temperature range can eliminate the residual stress accumulated in the cold working process, promote the uniform distribution of alloying elements in the grain and the stabilization of phases, and different temperature points correspond to different stabilization effects and residual stress elimination degrees; within the above annealing time range, it is beneficial to more complete stress release and element homogenization, while balancing the cost and production effect.For example, the stamping stage, the dynamic die gap is set to any value of 5%, 6%, 7%, 8% of the strip thickness or a range value between any two; the die gap determines the flow of the material during stamping, in the above die gap, the aluminum alloy strip has suitable flowability, which can ensure the basic shape and size of the part, and avoid cracks caused by excessive material flow; the springback amount after stamping is closely related to the die gap, using the above die gap, the springback of the part after demolding can be reduced, which is beneficial to obtaining accurate final size in the sizing stage; the above moderate die gap can provide a good balance in the fine stamping stage, which can reduce springback, without causing excessive material stretching or compression stress, and reducing the tendency of crack formation, and improving product qualification rate. For example, the flattening annealing temperature is 360℃, 370℃, 380℃; a large amount of residual stress will accumulate inside the flattened aluminum alloy disc, through the above temperature annealing process, the residual stress can be effectively eliminated, the dimensional stability and geometric precision can be improved, and the grain size can be more uniform, and the material hardness, strength and toughness can be adjusted through the above flattening annealing, so that it is more stable and durable in use. The present application can significantly reduce the springback, warpage and residual stress by optimizing the aluminum alloy formula and preparation process; the disc precision and dimensional stability are improved.

[0044] In order to improve the hot rolling effect and be more conducive to the subsequent process, in the hot rolling process, in addition to controlling the hot rolling speed, the hot rolling pass number, single pass reduction rate and total reduction amount also need to be controlled; for example, the total reduction amount of hot rolling is 98%~99.5%, further 98.5~99.5%; the pass reduction amount of hot rolling is first increased and then decreased; the pass number of hot rolling is 20~25 passes, further 20~23 passes, and the single pass reduction rate is 1%~40%; under this hot rolling parameter, the grain can be effectively refined, the material surface quality can be improved, and defects such as surface cracks can be reduced. This structure is beneficial to improve the strength, plasticity and corrosion resistance of the plate; by designing the single pass reduction amount to be first increased and then decreased, the grain orientation can be controlled, the grain anisotropy can be reduced, and the comprehensive performance of the plate, including dimensional stability and formability, can be improved; large reduction amount hot rolling can eliminate the internal residual stress of the metal plate, reduce the warpage and springback of the plate after deformation, and improve the preparation precision of the disc; by controlling the total reduction amount, rolling pass number and rolling speed, the uniform distribution of alloying elements in the grain can be promoted, segregation can be reduced, and the isotropy and overall performance of the material can be improved. After further optimizing the hot rolling process, the grain can be more fine, which is more conducive to the subsequent process; the grain morphology of the hot rolled plate is fibrous, and the plate thickness is 2~6mm, further 3~6mm.

[0045] The hot-rolled plate is air-cooled to below 100°C (room temperature) and then cold-rolled; the process parameters of cold-rolling affect the microstructure and mechanical properties of the plate; the total reduction of cold-rolling is 70-95%; further 75-92%; further still 75-85%; the cold-rolling passes are 1-4 passes, further 1-2 passes; the thickness of the cold-rolled plate is 0.5-1.5 mm. By optimizing the above cold-rolling process parameters, the grains are further refined at the above large cold-rolling reduction, which can promote the strength and plasticity of the plate, help to eliminate the internal accumulated residual stress, reduce the plate warping or springback, and improve the dimensional stability; the above reduction can improve the microstructure, promote the uniform distribution of metal elements, reduce segregation, improve the isotropy of the plate, and improve the high precision of the mechanical disc.

[0046] To further improve the flatness of the plate and eliminate or reduce various deformations and residual stresses generated during the preparation process of the plate, the cold-rolled plate needs to be straightened, and the deformation rate of straightening is controlled at 1-3%; specifically in the straightening process, it includes rough straightening, fine straightening, and shaping in turn; the tension of rough straightening is 25-35 kN, the pressure of fine straightening is 45-55 kN, and the pressure of shaping is 65-75 kN. By the way of gradually increasing the tension in stages for straightening, the warping and wavy deformation of the plate can be significantly improved under the action of the rough straightening tension, laying a foundation for thickness fine straightening and shaping; the deformation in the straightening process helps to reduce the anisotropy of the material, improve the grain consistency and uniformity; under the fine straightening pressure, the accumulation of internal residual stress caused by deformation during the processing of the plate and the redistribution of these residual stresses can be effectively released, making the plate more balanced and stable; under the shaping pressure, the tension is higher, which can further improve the flatness of the plate, reduce surface defects such as slight unevenness or scratches, and improve the surface quality; after the above straightening operation, the plate is easier to be accurately positioned and processed, which is beneficial to the subsequent stamping to form a high-precision disc and improves the product qualification rate.

[0047] After the above-mentioned cold-rolled plate is subjected to the stabilizing annealing treatment, the grain size of the plate or the strip after being cut is more refined, the grain size (i.e. the maximum length of the grain) is 16-20 μm, the anisotropy index Δr of the plate or the strip is ≤0.1, and the stabilizing annealing is performed in an air furnace. After the above-mentioned cold-rolling and hot-rolling processes, the grain size is small, the distribution is uniform, the residual stress is significantly reduced, the surface warping degree of the material is low, and the anisotropy index is significantly reduced. At this time, the quality of the aluminum alloy plate has reached a better state, and can fully meet the requirements of the disc material. In order to further improve the precision of the punched disc, the dynamic compensation coefficient K of the die during punching is controlled to be 1.05-1.12. Moreover, the punching process is refined to sequentially include preforming, fine punching, and shaping. The blank holder force of the preforming is 70-90 kN, the blank holder force of the fine punching is 110-130 kN, and the blank holder force of the shaping is 140-160 kN. After the punching is completed, flattening annealing is performed, which is performed in a non-active atmosphere, for example, in a nitrogen atmosphere. After the annealing, the mechanical disc is naturally cooled to 5-45 °C (room temperature). By adjusting the K value to the above-mentioned range, the elastic recovery and plastic deformation difference of the material during the punching process can be appropriately compensated, the stress and strain distribution on the plate can be accurately controlled at different stages of the pre-shaping, fine punching, and shaping, the local excessive deformation of the plate during the punching process can be reduced, the surface cracks or wrinkles and other defects on the surface of the plate can be reduced, the springback and warping of the plate after the punching can be reduced, and the dimensional precision and consistency can be improved.

[0048] According to a second aspect of the present application, a mechanical disc is provided, which is prepared by the above-mentioned method for preparing a mechanical disc. The warping degree of the mechanical disc is reduced to below 0.01 mm / m, the springback amount is controlled to be below 1.0‰, and the residual stress is reduced to below 75 MPa, thereby greatly improving the forming precision and the qualification rate of the aluminum alloy mechanical disc. Especially after the process parameters are optimized, the disc precision is further improved, the warping degree of the mechanical disc is ≤0.006 mm / m, the grain length (maximum length) of the mechanical disc is 22-34 μm, and the grain morphology is equiaxed grain.

[0049] The present application will be further described in detail below in conjunction with specific examples, which cannot be understood as limiting the scope of the present application.

[0050] The raw materials of the embodiments of the present application are all prior art and can be commercially available.

[0051] Example 1

[0052] A method for preparing an aluminum alloy mechanical disc, as shown in Figure 1 , includes the following steps:

[0053] Step S1, melting and casting: according to the proportion of each element: Si 0.015%, Fe 0.02%, Mg 4.0%, Zn 0.3%, Ti 0.005%, the balance being Al, totaling 100wt%, Mg:Si=266.7; melt and cast each raw material at 700°C (using a semi-continuous casting process) to obtain an aluminum alloy ingot;

[0054] Step S2, hot rolling: hot rolling treatment is performed on the above aluminum alloy ingot, with a starting rolling temperature of 490°C and a final rolling temperature of 320°C; the pass reduction rate distribution is as follows: 4% for the first pass, 5% for the second pass, 7% for the third pass, 7% for the fourth pass, 8% for the fifth pass, 9% for the sixth pass, 9% for the seventh pass, 10% for the eighth pass, 12% for the ninth pass, 13% for the tenth pass, 15% for the eleventh pass, 18% for the twelfth pass, 20% for the thirteenth pass, 24% for the fourteenth pass, 26% for the fifteenth pass, 29% for the sixteenth pass, 32% for the seventeenth pass, 40% for the eighteenth pass, 40% for the nineteenth pass, 39% for the twentieth pass, 36% for the twenty-first pass, 29% for the twenty-second pass, 20% for the twenty-third pass, and the total reduction rate is 99.5%; after hot rolling, air cooling is performed to room temperature to obtain a hot-rolled plate with a thickness of 2mm;

[0055] Step S3, cold rolling: cold rolling is performed on the above hot-rolled plate to obtain a cold-rolled plate with a thickness of 0.5mm; wherein the cold rolling pass is 1, and the total cold rolling reduction rate is 75%;

[0056] Step S4, straightening: the cold-rolled plate is sequentially subjected to three-stage tension straightening: 30kN (rough straightening), 50kN (fine straightening), and 70kN (shaping) to obtain a straightened plate with a deformation rate of 2%; then the straightened plate is subjected to stable annealing at 300°C for 12h in an air furnace to obtain an annealed plate with a grain size of 18±2μm; then the annealed plate is cut into strips with a size of 150mm wide; after three-stage tension straightening, the flatness of the plate is ≤0.01mm / m, the anisotropy index Δr=0.08, and the residual stress is reduced to below 90MPa;

[0057] Step S5, disc stamping: the strip is stamped, the die dynamic compensation coefficient K is set to 1.1; the die preforming gap ratio is set to 5% of the thickness of the strip (the blank holder force is 80 kN, and the speed is 15 mm / s); no crack is generated, the contour accuracy is ±0.1 mm; the fine blanking gap ratio is 7% of the thickness of the strip (the blank holder force is 120 kN, and the speed is 8 mm / s), the cross section roughness Ra is less than or equal to 1.6 μm; the sizing gap ratio is 8% of the thickness of the strip (the blank holder force is 150 kN, and the speed is 3 mm / s), and the springback amount is controlled to be 1.0‰. The disc is stamped, and the disc is subjected to flattening annealing: the disc is annealed at a temperature of 370 ℃ for 1.5 h under the protection of nitrogen (the oxygen content is less than or equal to 50 ppm); the disc warping degree is 0.005 mm / m; the residual stress is 70 MPa, the dimensional stability is improved; and the disc micro-morphology is as shown in FIG. 2. Figure 2

[0058] Example 2

[0059] Step S1, melting and casting: ingredients are prepared according to the proportion of each element: Si 0.0125%, Fe 0.1%, Mg 2.5%, Zn 0.1%, Ti 0.001%, and the balance is Al, the total is 100 wt%, and Mg:Si=200; the silicon-aluminum alloy, the iron-aluminum alloy, the magnesium-aluminum alloy, the zinc-aluminum alloy, and the titanium-aluminum alloy are melted and cast at 700 ℃ according to the proportion (a semi-continuous melting and casting process is adopted), to obtain an aluminum alloy ingot;

[0060] Step S2, hot rolling: the aluminum alloy ingot is subjected to hot rolling treatment, the starting rolling temperature is 480 ℃, the final rolling temperature is 310 ℃, and the pass reduction rate distribution is as follows: the first pass is 4%, the second pass is 5%, the third pass is 7%, the fourth pass is 7%, the fifth pass is 8%, the sixth pass is 8%, the seventh pass is 9%, the eighth pass is 10%, the ninth pass is 11%, the tenth pass is 13%, the eleventh pass is 14%, the twelfth pass is 17%, the thirteenth pass is 18%, the fourteenth pass is 23%, the fifteenth pass is 25%, the sixteenth pass is 31%, the seventeenth pass is 39%, the eighteenth pass is 40%, the nineteenth pass is 27%, the twentieth pass is 27%, the twenty-first pass is 25%, and the twenty-second pass is 11%, and the total reduction rate is 99%; after the hot rolling, the hot-rolled plate is obtained by air cooling to room temperature, and the thickness is 4 mm;

[0061] Step S3, cold rolling: the hot-rolled plate is subjected to cold rolling to obtain a cold-rolled plate with a thickness of 1.0 mm; wherein the cold rolling passes are 2, and the total cold rolling reduction is 75%.

[0062] ​Step S4, straightening: sequentially performing three-stage tension straightening on the cold-rolled plate: 25 kN (rough straightening), 45 kN (fine straightening), and 65 kN (shaping), to obtain a straightened plate, with a deformation rate of 1%; then performing stable annealing at 280°C for 13 h in an air furnace to obtain an annealed plate, with a grain size of 18±2 μm; then performing slitting to obtain a strip with a size of 150 mm in width; after three-stage tension straightening, the flatness of the plate is ≤0.01 mm / m, the anisotropy index Δr=0.05, and the residual stress is reduced to below 85 MPa;

[0063] Step S5, disc punching: punching the strip; setting the dynamic makeup coefficient of the die K=1.05; setting the preforming gap ratio of the die as 5% of the thickness of the strip (the blank holder force is 70 kN, and the speed is 15 mm / s), without crack generation, and the contour accuracy is ±0.1 mm; setting the fine punching gap ratio as 7% of the thickness of the strip (the blank holder force is 110 kN, and the speed is 8 mm / s), with a cross-sectional roughness Ra≤1.6 μm; setting the shaping gap ratio as 8% of the thickness of the strip (the blank holder force is 140 kN, and the speed is 3 mm / s), with a springback amount controlled within 1.0‰. Punching to obtain a disc, and performing flattening annealing on the disc: annealing at 360°C under nitrogen protection for 2 h; the disc warping degree is 0.004 mm / m; the residual stress is reduced to 68 MPa, and the dimensional stability is improved.

[0064] Example 3

[0065] Step S1, melting and casting: according to the proportion of each element: Si 0.01%, Fe 0.25%, Mg 4.0%, Zn 0.5%, Ti 0.01%, and the balance being Al, with a total of 100 wt%, Mg:Si=400; melting and casting (using a semi-continuous casting process) the silicon-aluminum alloy, the iron-aluminum alloy, the magnesium-aluminum alloy, the zinc-aluminum alloy, and the titanium-aluminum alloy at 700°C to obtain an aluminum alloy ingot;

[0066] Step S2, hot rolling: performing hot rolling on the aluminum alloy ingot, with a starting rolling temperature of 500°C and a final rolling temperature of 330°C; the pass reduction rate distribution is: 4% for the first pass, 6% for the second pass, 7% for the third pass, 7% for the fourth pass, 8% for the fifth pass, 9% for the sixth pass, 9% for the seventh pass, 10% for the eighth pass, 12% for the ninth pass, 13% for the tenth pass, 15% for the eleventh pass, 18% for the twelfth pass, 19% for the thirteenth pass, 25% for the fourteenth pass, 30% for the fifteenth pass, 40% for the sixteenth pass, 40% for the seventeenth pass, 40% for the eighteenth pass, 25% for the nineteenth pass, and 20% for the twentieth pass, with a total reduction rate of 98.5%; after hot rolling, water cooling to room temperature is performed to obtain a hot-rolled plate with a thickness of 6 mm;

[0067] Step S3, cold rolling: the hot-rolled plate is cold-rolled to obtain a cold-rolled plate with a thickness of 1 mm; wherein the cold rolling pass is 1 and the total cold rolling reduction is 83%;

[0068] Step S4, straightening: the cold-rolled plate is sequentially subjected to three-stage tension straightening: 35 kN (rough straightening), 55 kN (fine straightening), and 75 kN (shaping) to obtain a straightened plate with a deformation rate of 3%; the straightened plate is then subjected to stable annealing at 350 °C for 11 h in an air furnace to obtain an annealed plate with a grain size of 18 ± 2 μm; the annealed plate is then cut into strips with a size of 150 mm; the plate after three-stage tension straightening has a flatness of ≤0.05 mm / m, an anisotropy index Δr = 0.06, and a residual stress reduced to below 90 MPa;

[0069] Step S5, disc punching: the strip is punched to set the die dynamic compensation coefficient K = 1.12; the die preforming gap ratio is set to 5% of the thickness of the strip (the blank holder force is 90 kN and the speed is 15 mm / s), no cracks are generated, and the contour accuracy is ±0.1 mm; the fine punching gap ratio is 7% of the thickness of the strip (the blank holder force is 130 kN and the speed is 8 mm / s), the cross-sectional roughness Ra is ≤1.6 μm; the shaping gap ratio is 8% of the thickness of the strip (the blank holder force is 160 kN and the speed is 3 mm / s), and the springback amount is controlled to be 1.0‰. The punching obtains a disc, and the disc is subjected to flattening annealing: annealing at 380 °C under nitrogen protection for 1 h; the disc has a warping degree of 0.006 mm / m; the residual stress is reduced to 72 MPa, and the dimensional stability is improved.

[0070] Example 4

[0071] Example 4 differs from Example 1 in that the proportions of the elements in Step S1 are as follows: Si 0.018%, Fe 0.15%, Mg 5.5%, Zn 0.3%, Ti 0.005%, and the balance is Al, with the total being 100 wt%, and Mg:Si = 305.6.

[0072] Example 5

[0073] Example 5 differs from Example 1 in that the proportions of the elements in Step S1 are as follows: Si 0.014%, Fe 0.20%, Mg 4.9%, Zn 0.4%, Ti 0.008%, and the balance is Al, with the total being 100 wt%, and Mg:Si = 350.

[0074] Example 6

[0075] Example 6 differs from Example 1 in that the proportions of the elements in Step S1 are as follows: Si 0.0275%, Fe 0.20%, Mg 5.5%, Zn 0.4%, Ti 0.008%, and the balance is Al, with the total being 100 wt%, and Mg:Si = 200.

[0076] Example 7

[0077] Example 7 differs from Example 1 in that the finishing temperature of step S2 is replaced by 350℃.

[0078] Example 8

[0079] Example 8 differs from Example 1 in that the total cold rolling reduction in step S3 is replaced by 70%.

[0080] Example 9

[0081] Example 9 differs from Example 1 in that the cold rolling 3 passes, total reduction in step S3 is replaced by 85%.

[0082] Example 10

[0083] Example 10 differs from Example 1 in that the cold rolling 4 passes, total reduction in step S3 is replaced by 90%.

[0084] Comparative Example 1

[0085] Comparative Example 1 differs from Example 1 in that the elemental composition in step S1 is: Si 0.01%, Fe 0.15%, Mg 5.0%, Zn 0.3%, Ti 0.005%, the balance being Al, totaling 100wt%, Mg:Si = 500.

[0086] Comparative Example 2

[0087] Comparative Example 2 differs from Example 1 in that the elemental composition in step S1 is: Si 0.025%, Fe 0.35%, Mg 2.5%, Zn 0.3%, Ti 0.005%, the balance being Al, totaling 100wt%, Mg:Si = 100.

[0088] Comparative Example 3

[0089] Comparative Example 3 differs from Example 1 in that the elemental composition in step S1 is: Si 0.015%, Fe 0.35%, Mg 4.0%, Zn 0.3%, Ti 0.005%, the balance being Al, totaling 100wt%, Mg:Si = 266.7.

[0090] Comparative Example 4

[0091] Comparative Example 4 differs from Example 1 in that the starting temperature of the hot rolling process in step S2 is replaced by 450℃, and the finishing temperature is replaced by 260℃.

[0092] Comparative Example 5

[0093] Comparative Example 5 and Example 1 differ in that the stabilizing annealing temperature in Step S4 is replaced by 250℃, and annealing is performed for 1h.

[0094] Performance test:

[0095] The warpage and springback of the mechanical disc of each example and comparative example are measured by an optical profiler, and the residual stress is measured by an X-ray diffractometer.

[0096] The performance of the aluminum alloy mechanical disc prepared in each example and each comparative example is detected, and the results are shown in Table 1.

[0097] Table 1

[0098] Sample Warpage (mm / m) Rebound (‰) Residual stress (MPa) Grain length (pm) Example 1 0.005 1.0 70 25 Example 2 0.004 1.0 68 22 Example 3 0.006 1.0 72 34 Example 4 0.005 1.0 75 26 Example 5 0.006 1.0 74 28 Example 6 0.008 1.0 75 33 Example 7 0.004 1.0 75 23 Example 8 0.007 1.0 73 28 Example 9 0.005 1.0 67 23 Example 10 0.004 1.0 65 22 Comparative Example 1 0.020 1.2 87 38 Comparative Example 2 0.025 1.3 90 43 Comparative Example 3 0.030 1.3 98 50 Comparative Example 4 0.024 1.2 91 45 Comparative Example 5 0.033 1.4 93 58

[0099] The test results in Table 1 show that the warpage of the mechanical disc prepared in each example of the present application is below 0.01mm / m, the springback is below 1.0‰, the residual stress is reduced to below 75MPa, the maximum length of the crystal grain is 22-34μm, and the crystal grain morphology is equiaxed crystal. It can be seen that the best synergistic effect can be achieved by optimizing the element ratio of the aluminum alloy mechanical disc and the process parameters such as hot rolling, cold rolling and annealing.

[0100] In Comparative Example 1 and Comparative Example 2, the ratio of magnesium element and silicon element exceeds 400 or is less than 200, which is easy to form compounds of Mg and Si, so that the residual stress is increased. In Comparative Example 3, the proportion of iron element is more than 0.25%, which contains more iron particles, resulting in coarse crystal grain size and increased residual stress. In Comparative Example 4, the hot rolling starting temperature and the final rolling temperature are relatively low, and the residual stress generated by deformation is larger. In Comparative Example 5, the stabilizing annealing temperature of the cold rolled plate is relatively low, and the effect of eliminating the residual stress is weakened.

[0101] From the above comparison, it can be seen that by applying the preparation method of the mechanical disc provided in the present application, firstly, by optimizing the aluminum alloy formula, controlling the specific proportion of iron element and the specific ratio of magnesium / silicon two components, the strength and corrosion resistance of the aluminum alloy material are balanced to the best, and the tendency of the material to crack during the preparation of the disc is reduced; and secondly, by optimizing the disc preparation process, such as hot rolling, cold rolling, straightening, annealing, cutting, punching with a specific mold gap, and flattening annealing of the cast ingot in sequence at a specific temperature, pass, and reduction, the process parameters in each process are optimized, so that the aluminum alloy material and the process parameters are more suitable; the element ratio and the process parameters in each stage achieve the best synergistic effect, so that the warpage of the finally prepared mechanical disc is reduced to below 0.01mm / m, the springback is controlled to be below 1.0‰, and the residual stress is reduced to below 75MPa, which greatly improves the forming precision and the qualification rate of the aluminum alloy mechanical disc.

[0102] It should be noted that the terms "first", "second", and the like in the description and in the claims of the present application are used for distinguishing between similar objects and not necessarily for describing a specific sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the present application described herein are, for example, capable of orderly execution or performance.

[0103] The preferred embodiments of the present application have been described above with the understanding that these embodiments are intended to be illustrative and not restrictive of possible embodiments of the application. Changes and modifications can be made by those of ordinary skill in the art, which equate to the principles and spirit of the application, and it is therefore intended that this application include all such changes and modifications as fall within the scope of the appended claims.

Claims

1. A method for preparing a mechanical disk, characterized in that, The preparation method includes the following steps: Step S1: Prepare and melt the aluminum alloy according to the proportions of each element to obtain an ingot; wherein, by weight percentage, the proportions of each element are as follows: Si 0.01-0.03%, Fe 0.01-0.25%, Mg 2.5-5.5%, Zn 0.1-0.5%, Ti 0.001-0.01%, with the balance being aluminum and unavoidable impurities, totaling 100%; the weight ratio of Mg to Si is 200-400; Step S2: The ingot is hot-rolled to obtain a hot-rolled plate; wherein the initial rolling temperature is 480-500℃ and the final rolling temperature is ≥300℃. Step S3: Cold-roll the hot-rolled sheet to obtain a cold-rolled sheet; Step S4: The cold-rolled sheet is straightened, stabilized and annealed in sequence and slit to obtain strips; wherein the conditions for stabilization annealing include: annealing temperature of 280-350℃ and annealing time of 10-13h; Step S5: The strip material is sequentially stamped and flattened annealed to obtain the mechanical disc; wherein, the dynamic adjustment die clearance during stamping is 5-8% of the thickness of the strip material; the flattening annealing conditions include: annealing temperature of 360-380℃ and annealing time of 1-2h.

2. The method for preparing a mechanical disk according to claim 1, characterized in that, In step S2, the final rolling temperature of the hot rolling is 300-350°C; And / or, the total reduction rate of the hot rolling is 98-99.5%; And / or, the thickness of the hot-rolled plate is 2 to 6 mm.

3. The method for preparing a mechanical disk according to claim 1 or 2, characterized in that, The single-pass reduction rate of the hot rolling process first increases and then decreases. And / or, the hot rolling process has 20 to 25 passes, with a single pass reduction rate of 1% to 40%.

4. The method for preparing a mechanical disk according to any one of claims 1 to 3, characterized in that, In step S3, the hot-rolled plate is air-cooled to below 100°C before being cold-rolled. And / or, the total reduction rate of the cold rolling is 70-95%, and the number of cold rolling passes is 1-4.

5. The method for preparing a mechanical disk according to any one of claims 1 to 4, characterized in that, In step S3, the total reduction rate of the cold rolling is 75-85%, and the number of cold rolling passes is 1-2. And / or, the thickness of the cold-rolled sheet is 0.5 to 1.5 mm.

6. The method for preparing a mechanical disk according to any one of claims 1 to 5, characterized in that, In step S4, the deformation rate of the straightening is 1-3%; And / or, the straightening process includes coarse straightening, fine straightening, and shaping in sequence; And / or, the stabilizing annealing is performed in an air furnace; And / or, the anisotropy index Δr of the strip is ≤0.

1.

7. The method for preparing a mechanical disk according to any one of claims 1 to 6, characterized in that, In step S5, the dynamic compensation coefficient of the die during stamping is K = 1.05 to 1.12; And / or, in step S5, the stamping process sequentially includes preforming, fine stamping, and shaping.

8. The method for preparing a mechanical disk according to any one of claims 1 to 7, characterized in that, The flattening annealing is performed in a non-reactive atmosphere; And / or, step S5 is followed by step S6, which includes: the mechanical disk being naturally cooled to 5-45°C.

9. A mechanical disk, characterized in that, The mechanical disk is prepared by the method for preparing a mechanical disk according to any one of claims 1 to 8.

10. The mechanical disk according to claim 9, characterized in that, The mechanical disk has a warpage ≤0.01mm / m, a springback ≤1.0‰, and a residual stress ≤75MPa; the grain length of the mechanical disk is 22~34μm, and the grain morphology is equiaxed.

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