A method for preparing high-performance aluminum alloy heat sink plate

Abstract

This invention relates to a method for preparing high-performance aluminum alloy radiator plates. The method involves controlling the iron-silicon ratio of the main impurity component in the melt to be no less than 1.9 to reduce internal cracks in the cast billet and decrease the machining deformation rate of the finished product. This is achieved by adding aluminum-titanium alloy and a grain refiner in the furnace and online runner, while ensuring that the titanium content in the aluminum alloy ingot is maintained within a reasonable range, resulting in an ingot grain size ≤1. This improves the mechanical properties, uniform microstructure, and refined grains of the aluminum alloy radiator plate. Simultaneously, a small amount of copper is added, and the final rolling temperature is controlled at 330-360℃, resulting in fully recrystallized grains within the aluminum alloy plate. This improves the strength of the aluminum alloy radiator plate while eliminating anisotropy in its internal mechanical properties and reducing internal stress, ultimately yielding a high-performance aluminum alloy radiator plate.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy sheet manufacturing technology, and in particular to a method for preparing a high-performance aluminum alloy radiator sheet. Background Technology

[0002] The existing production process for aluminum alloy radiator sheets is as follows: casting large flat ingots (melting aluminum ingots or molten aluminum, batching, refining, degassing, slag removal and purification) → heating the flat ingots to 480-550℃ → rolling them into aluminum alloy sheets of various thicknesses on a hot rolling mill → leveling and straightening → precision sawing to length → heat treatment → finished product inspection, packaging and warehousing. The publicly disclosed aluminum alloy formula for heat dissipation has the following composition: Si: 0.2-0.6%; Mg: 0.6-1.5%; Cu: 0.8-1.5%; Mn: 0.10-0.2%; the balance being Al and trace impurities.

[0003] Existing aluminum alloy sheets suffer from low strength and poor uniformity, inconsistent hardness, and large deformation during sawing. The resulting fins are prone to twisting, uneven thickness, and uneven height, leading to uneven heat dissipation. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for preparing a high-performance aluminum alloy heat sink plate, which improves the mechanical properties of the heat sink aluminum alloy plate by means of uniform structure and grain refinement, balances the internal stress of the aluminum alloy plate, and reduces the degree of plate distortion.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0008] This invention provides a method for preparing a high-performance aluminum alloy heat sink plate, comprising:

[0009] S1. Prepare the required raw materials according to the composition requirements of aluminum alloy sheets;

[0010] The mass composition of the aluminum alloy sheet is as follows: Si: 0.06-0.08%, Cu: 0.12-0.17%, Fe: 0.12-0.15%, Ti: 0.01-0.015%, with the balance being Al and unavoidable impurities, wherein the Fe:Si mass ratio is ≥1.90; wherein Al is provided by high-purity aluminum ingots and Cu is provided by aluminum-copper alloys;

[0011] S2. Clean and dry the surface of each raw material to ensure that the raw materials are free of moisture and impurities;

[0012] S3. High-purity aluminum ingots are put into the melting furnace and heated to 730-750℃ at a rate of 8-10℃ / min until they are completely melted.

[0013] S4. Add the preheated aluminum-copper alloy into the furnace and reduce the temperature to 650-680℃ at a rate of 3-5℃ / min to completely melt the aluminum-copper alloy. Hold the temperature for 1-1.5 hours while stirring and removing slag.

[0014] S5. Add aluminum-titanium alloy into the furnace to refine the grains, and introduce nitrogen into the furnace for degassing and refining agent for refining to obtain aluminum alloy melt.

[0015] S6. Add Al-5Ti-B wire or titanium-zirconium alloy to the online flow channel outside the furnace, and then control the temperature of the obtained aluminum alloy melt at 730-750℃ for casting.

[0016] S7. Cut off the pouring gate and sprue head of the cast aluminum alloy ingot, and mill off the surface segregation layer.

[0017] S8. Heat the milled aluminum alloy ingot to 450-470℃ and hold for ≥12h. Place it on the roller table and cool it to 400-420℃ at a rate of 3-5℃ / min before rolling. Control the rolling temperature to the finished thickness at 330-360℃.

[0018] S9. Place the hot-rolled plate at 330-360℃ on a material rack with a flatness of no more than 1mm and allow it to air cool naturally.

[0019] S10. Cut the cooled hot-rolled plate to length and then flatten it.

[0020] S11. Stack the flat aluminum alloy sheets into the heat treatment furnace and keep them at 150-175℃ for ≥17h. Then, remove them from the furnace and air cool them to room temperature.

[0021] In this invention, based on the titanium content of the finished aluminum alloy radiator plate being 0.01-0.015%, the aluminum-titanium alloy added in S5 has a composition of 95% Al + 5% Ti, with approximately 2.5-3 kg of aluminum-titanium alloy added per ton of molten aluminum; in S6, Al-5Ti-B wire is added to the online flow channel, with approximately 2-2.2 kg of aluminum-titanium-boron wire added per ton of molten aluminum; if in S6 a titanium-zirconium alloy (Ti: 0.032%, Zr: 0.005%, with the balance being Al) is added to the online flow channel, the amount added is approximately 5-6.4 kg / ton of molten aluminum.

[0022] According to a preferred embodiment of the present invention, in S2, the temperature is raised to 120°C at a rate of 10°C / min and kept at that temperature for ≥2 hours for drying.

[0023] According to a preferred embodiment of the present invention, in S5, the degassing and refining time is 30 min.

[0024] According to a preferred embodiment of the present invention, in S6, the Al-5Ti-B wire is replaced with a Ti+Zr combined refining agent, which contains Ti: 0.032-0.037% and Zr: 0.005-0.0075%.

[0025] According to a preferred embodiment of the present invention, in S8, the milled aluminum alloy ingot is heated to 450-470°C and held for 17 hours.

[0026] According to a preferred embodiment of the present invention, in S9, the time for the hot-rolled plate to cool to room temperature is not less than 72 hours.

[0027] According to a preferred embodiment of the present invention, in S9, during air cooling on the material rack, stainless steel strips of 2.5-3.5*(10-20)*(1000-2000)mm are placed between the plates, with a spacing of ≤500mm. The stainless steel strips have a thickness of 2.5-3.5mm, a width of 10-20mm, and a length of 1000-2000mm.

[0028] According to a preferred embodiment of the present invention, in S10, the strips are first sawn and then leveled and straightened, and then straightened for 7 passes on a roller straightening machine.

[0029] According to a preferred embodiment of the present invention, in S11, the furnace temperature is first raised to 260°C at a heating rate of 0.5°C / min, the flattened aluminum alloy plates are stacked into the heat treatment furnace, the temperature is lowered to 170±3°C and held for 17-22 hours, and then the plates are removed from the furnace.

[0030] (III) Beneficial Effects

[0031] This invention reduces internal cracks in the billet and decreases the machining deformation rate of the finished product by controlling the iron-silicon ratio of the main impurity component in the melt to be no less than 1.9 when designing the alloy formulation of aluminum alloy sheets. It also controls the copper content to improve the mechanical properties of the aluminum alloy sheets. In steps S5 and S6, aluminum-titanium alloy is added into the furnace, and titanium (Al-5Ti-B wire or Ti+Zr combined grain refiner) is added into the online flow channel (outside the furnace) to refine the grain size. This ensures that the titanium content in the aluminum alloy ingot is maintained within a reasonable range, resulting in an ingot grain size ≤1 grade. This improves the mechanical properties, uniform microstructure, and grain refinement of the heat sink aluminum alloy sheets. This invention optimizes the formulation and the type and method of adding the grain refiner. At the same time, by adding a small amount of copper and controlling the final rolling temperature of the finished product to 330-360℃, the internal grains of the aluminum alloy sheet are fully recrystallized grains. This not only improves the strength of the aluminum alloy radiator sheet, but also eliminates the anisotropy of the internal mechanical properties of the aluminum alloy sheet, reduces internal stress, and ultimately obtains a high-performance aluminum alloy radiator sheet.

[0032] Improvements to the aluminum alloy ingot heating process in S8 result in a more uniform internal structure, consistent surface hardness, and balanced internal stress in the ingot. Innovations in the cooling methods and heat treatment of hot-rolled plates in S9-S11 minimize and evenly distribute internal stress, preventing deformation during sawing. Ultimately, the surface hardness of the finished plates reaches 25-28 HB. Detailed Implementation

[0033] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to specific embodiments.

[0034] Example 1

[0035] This embodiment provides a method for preparing a high-performance aluminum alloy heat sink plate. The alloy composition of the aluminum alloy plate consists of the following components by mass percentage: Si: 0.06%, Cu: 0.17%, Fe: 0.12%, Ti: 0.015%, with the balance being Al and unavoidable impurities, wherein the Fe:Si mass ratio is 2. By controlling the iron-silicon ratio, the main impurity component of the melt, to be not less than 1.9, internal cracks in the billet are reduced, and the processing deformation rate of the finished product is reduced. The copper content is controlled to improve the mechanical properties of the aluminum alloy plate.

[0036] The preparation method of aluminum alloy heat sink plate is as follows:

[0037] (1) Smelting and casting: Prepare materials according to the designed alloy composition.

[0038] (2) Raw material cleaning: Clean and dry the surface of each raw material to ensure that the raw materials are free of moisture and impurities; during drying, raise the temperature to 120℃ at a rate of 10℃ / min and keep it at that temperature for 2 hours.

[0039] (3) Melting and casting the batched aluminum alloy, including:

[0040] During smelting, the temperature is first raised to 750°C at a rate of 10°C / min to completely melt the alloy. Then, the preheated aluminum-copper alloy is added, and the temperature is lowered to 660°C at a rate of 5°C / min to completely melt the alloy. The temperature is held for 1.5 hours while stirring and removing slag. Then, aluminum-titanium alloy (95% Al + 5% Ti, 3.0 kg / ton of molten aluminum) is added to the smelting furnace to refine the grains. Nitrogen gas is then introduced into the furnace for degassing and refining, and the furnace is refined for 30 minutes to obtain the molten aluminum alloy.

[0041] Al-5Ti-B wire is added to an online ladle outside the furnace. The resulting molten aluminum alloy is then cast at a temperature controlled at 740±3℃ to produce large-sized aluminum alloy flat ingots with dimensions of 400mm×1000mm×3000mm. The H content of the melt is approximately 0.16mg / 100gAl. A combination of in-furnace and out-of-furnace online refining methods is employed to ensure the porosity of the aluminum alloy rods reaches Grade 1. Al-5Ti-B wire is added to the ladle, with 2Kg of aluminum-titanium-boron wire added per ton of molten aluminum to control the content of the aluminum alloy heat sink material within a preset range.

[0042] (4) Machining: Cut off the pouring port and the ingot head of the aluminum alloy flat ingot, and mill off the surface segregation layer. Cut off the head, tail and surface of the obtained flat ingot, with 120mm cut off the head and tail, and 15mm cut off the upper and lower surfaces.

[0043] (5) Preheating and homogenization heat treatment: The milled aluminum alloy ingot is heated to 460±2℃ and held for 17h, and then cooled to 410±3℃ at a speed of 5℃ / min on the roller conveyor to obtain a flat ingot with casting stress and composition segregation eliminated.

[0044] (6) Hot rolling: The preheated ingot is hot rolled in multiple passes to obtain a large-size aluminum alloy plate with a thickness of 200mm and a width of 1250mm. The final rolling temperature is 360℃.

[0045] (7) Placement: Place the 360°C hot-rolled plate on a rack with a flatness of no more than 1 mm and allow it to air cool naturally for 72 hours. When stacking hot-rolled plates, place several 3*20*1300mm stainless steel strips between the plates, with a spacing of 500mm between the stainless steel strips.

[0046] (8) Leveling: The cooled hot-rolled plate is first cut to length and then leveled; during leveling, it is first cut into strips and then leveled and straightened. It is straightened in 7 passes on a roller straightening machine, and the straightening stretch rate is 3.8%.

[0047] (9) Artificial aging: The furnace temperature is raised to 260℃ at a heating rate of 0.5℃ / min. The flat aluminum alloy plates are stacked into the heat treatment furnace, cooled to 170±3℃ and held for 22 hours. The high-performance aluminum alloy radiator plates are then obtained.

[0048] Example 2

[0049] This embodiment provides a method for preparing a high-performance aluminum alloy heat sink plate. The alloy composition of the aluminum alloy plate consists of the following components by mass percentage: Si: 0.07%, Cu: 0.12%, Fe: 0.15%, Ti: 0.015%, with the balance being Al and unavoidable impurities, wherein the Fe:Si mass ratio is 2.14.

[0050] The preparation method of aluminum alloy heat sink plate is as follows:

[0051] (1) Smelting and casting: Prepare materials according to the designed alloy composition.

[0052] (2) Raw material cleaning: Clean and dry the surface of each raw material to ensure that the raw materials are free of moisture and impurities; during drying, raise the temperature to 120℃ at a rate of 10℃ / min and keep it at that temperature for 2 hours.

[0053] (3) Melting and casting the batched aluminum alloy, including:

[0054] During smelting, the temperature is first raised to 740°C at a rate of 8°C / min to completely melt the aluminum-copper alloy. Then, the preheated aluminum-copper alloy is added, and the temperature is lowered to 680°C at a rate of 5°C / min to completely melt the aluminum-copper alloy. The temperature is held for 1 hour while stirring and removing slag. Then, aluminum-titanium alloy (95% Al + 5% Ti, 2.95 kg / ton of molten aluminum) is added to the smelting furnace to refine the grains. Nitrogen gas is then introduced into the furnace for degassing and refining agents for 30 minutes to obtain molten aluminum alloy.

[0055] A Ti+Zr composite refining agent (Ti: 0.032%, Zr: 0.005%, balance Al) was added to an online ladle outside the furnace. The resulting molten aluminum alloy was then cast at a temperature controlled at 740±3℃ to produce large-sized aluminum alloy flat ingots with dimensions of 400mm×1000mm×3000mm. The H content of the melt was approximately 0.21mg / 100gAl. When using the Ti+Zr composite refining agent, it was added at a rate of 5.5Kg / ton of molten aluminum to control the content of the aluminum alloy radiator plate within the preset range.

[0056] (4) Machining: Cut off the pouring port and the ingot head of the aluminum alloy flat ingot, and mill off the surface segregation layer. Cut off the head, tail and surface of the obtained flat ingot, with 120mm cut off the head and tail, and 15mm cut off the upper and lower surfaces.

[0057] (5) Preheating and homogenization heat treatment: The milled aluminum alloy ingot is heated to 468-470℃ and held for 12 hours, and then cooled to 415±2℃ at a speed of 5℃ / minute on the roller conveyor to obtain a flat ingot with casting stress and composition segregation eliminated.

[0058] (6) Hot rolling: The preheated ingot is hot rolled in multiple passes to obtain a large-size aluminum alloy plate with a thickness of 200mm and a width of 1200mm. The final rolling temperature is 355℃.

[0059] (7) Placement: Place the 355℃ hot-rolled plate on a material rack with a flatness of no more than 1mm and air cool naturally for 72 hours. When stacking hot-rolled plates, place several 3*20*1300mm stainless steel strips between the plates, and the spacing between the stainless steel strips is 500mm.

[0060] (8) Leveling: Cut the cooled hot-rolled plate into lengths and then level it. When leveling, cut the plate into strips and then level and straighten it. Straighten it for 7 passes on a roller straightening machine. The straightening stretch rate is 3.5%.

[0061] (9) Artificial aging: The furnace temperature is raised to 260℃ at a heating rate of 0.5℃ / min. The flat aluminum alloy plates are stacked into the heat treatment furnace, cooled to 170±2℃ and held for 17h. The high-performance aluminum alloy radiator plates are then obtained.

[0062] Example 3

[0063] This embodiment provides a method for preparing a high-performance aluminum alloy heat sink plate. The alloy composition of the aluminum alloy plate consists of the following components by mass percentage: Si: 0.065%, Cu: 0.12%, Fe: 0.13%, Ti: 0.015%, with the balance being Al and unavoidable impurities, wherein the Fe:Si mass ratio is 2.

[0064] The preparation method of aluminum alloy heat sink plate is as follows:

[0065] (1) Smelting and casting: Prepare materials according to the designed alloy composition.

[0066] (2) Raw material cleaning: Clean and dry the surface of each raw material to ensure that the raw materials are free of moisture and impurities; during drying, raise the temperature to 120℃ at a rate of 10℃ / min and keep it at that temperature for 2 hours.

[0067] (3) Melting and casting the batched aluminum alloy, including:

[0068] During smelting, the temperature is first raised to 740℃ at a rate of 10℃ / min to completely melt the alloy. Then, the preheated aluminum-copper alloy is added, and the temperature is lowered to 660℃ at a rate of 3℃ / min to completely melt the alloy. The temperature is held for 1.5 hours while stirring and removing slag. Then, aluminum-titanium alloy (95% Al + 5% Ti, 2.95 kg / ton of molten aluminum) is added to the smelting furnace to refine the grains. Nitrogen gas is then introduced into the furnace for degassing and refining, and the furnace is refined for 30 minutes to obtain the molten aluminum alloy.

[0069] Al-5Ti-B wire is added to the online flow channel outside the furnace at a rate of 2.1 kg / ton of molten aluminum. The temperature of the resulting aluminum alloy melt is then controlled at 735±5℃ for casting, producing large-sized aluminum alloy flat ingots with dimensions of 400mm×1000mm×3000mm. The H content of the melt is approximately 0.25 mg / 100gAl.

[0070] (4) Machining: Cut off the pouring port and the ingot head of the aluminum alloy flat ingot, and mill off the surface segregation layer. Cut off the head, tail and surface of the obtained flat ingot, with 120mm cut off the head and tail, and 15mm cut off the upper and lower surfaces.

[0071] (5) Preheating and homogenization heat treatment: The milled aluminum alloy ingot is heated to 465-466℃ and held for 12 hours, and then cooled to 410-415℃ on the roller conveyor at a rate of 5℃ / minute to obtain a flat ingot with eliminated casting stress and composition segregation.

[0072] (6) Hot rolling: The preheated ingot is hot rolled in multiple passes to obtain a large-size aluminum alloy plate with a thickness of 200mm and a width of 1200mm. The final rolling temperature is 335℃.

[0073] (7) Placement: Place the 335℃ hot-rolled plate on a material rack with a flatness of no more than 1mm and allow it to air cool naturally for 72 hours. When stacking hot-rolled plates, place several 3*20*1300mm stainless steel strips between the plates, with a spacing of 500mm between the stainless steel strips.

[0074] (8) Leveling: The cooled hot-rolled plate is first cut to length and then leveled; during leveling, it is first cut into strips and then leveled and straightened. It is straightened in 7 passes on a roller straightening machine, and the straightening stretch rate is 3.6%.

[0075] (9) Artificial aging: The furnace temperature is raised to 260℃ at a heating rate of 0.5℃ / min. The flat aluminum alloy plates are stacked into the heat treatment furnace, cooled to 170±2℃ and held for 20h. The high-performance aluminum alloy radiator plates are then obtained.

[0076] Example 4

[0077] This embodiment provides a method for preparing a high-performance aluminum alloy heat sink plate. The alloy composition of the aluminum alloy plate consists of the following components by mass percentage: Si: 0.07%, Cu: 0.16%, Fe: 0.14%, Ti: 0.015%, with the balance being Al and unavoidable impurities, wherein the Fe:Si mass ratio is 2.

[0078] The preparation method of aluminum alloy heat sink plate is as follows:

[0079] (1) Smelting and casting: Prepare materials according to the designed alloy composition.

[0080] (2) Raw material cleaning: Clean and dry the surface of each raw material to ensure that the raw materials are free of moisture and impurities; during drying, raise the temperature to 120℃ at a rate of 10℃ / min and keep it at that temperature for 2 hours.

[0081] (3) Melting and casting the batched aluminum alloy, including:

[0082] During smelting, the temperature is first raised to 740℃ at a rate of 8℃ / min to completely melt the aluminum-copper alloy. Then, the preheated aluminum-copper alloy is added, and the temperature is lowered to 660℃ at a rate of 5℃ / min to completely melt the aluminum-copper alloy. The temperature is held for 1.5 hours while stirring and removing slag. Then, aluminum-titanium alloy (95% Al + 5% Ti, 2.9 kg / ton of molten aluminum) is added to the smelting furnace to refine the grains. Nitrogen gas is then introduced into the furnace for degassing and refining agents for 30 minutes to obtain the molten aluminum alloy.

[0083] Al-5Ti-B wire is added to the online flow channel outside the furnace at a rate of 2.2 kg / ton of molten aluminum. The temperature of the resulting aluminum alloy melt is then controlled at 740-742℃ for casting, producing large-sized aluminum alloy flat ingots with dimensions of 400 mm × 1000 mm × 3000 mm. The H content of the melt is approximately 0.22 mg / 100g Al.

[0084] (4) Machining: Cut off the pouring port and the ingot head of the aluminum alloy flat ingot, and mill off the surface segregation layer. Cut off the head, tail and surface of the obtained flat ingot, with 120mm cut off the head and tail, and 15mm cut off the upper and lower surfaces.

[0085] (5) Preheating and homogenization heat treatment: The milled aluminum alloy ingot is heated to 465-470℃ and held for 12 hours, and then cooled to 410-415℃ on the roller conveyor at a rate of 5℃ / minute to obtain a flat ingot with eliminated casting stress and composition segregation.

[0086] (6) Hot rolling: The preheated flat ingot is hot rolled in multiple passes to obtain a large-size aluminum alloy plate with a thickness of 200mm and a width of 1200mm. The final rolling temperature is 340℃.

[0087] (7) Placement: Place the 340℃ hot-rolled plate on a material rack with a flatness of no more than 1mm and allow it to air cool naturally for 72 hours. When stacking hot-rolled plates, place several 3*20*1300mm stainless steel strips between the plates, with a spacing of 500mm between the stainless steel strips.

[0088] (8) Leveling: The cooled hot-rolled plate is first cut to length and then leveled; during leveling, it is first cut into strips and then leveled and straightened. It is straightened in 7 passes on a roller straightening machine, and the straightening stretch rate is 4.0%.

[0089] (9) Artificial aging: The furnace temperature is raised to 260℃ at a heating rate of 0.5℃ / min. The flat aluminum alloy plates are stacked into the heat treatment furnace, cooled to 170±2℃ and held for 20h. The high-performance aluminum alloy radiator plates are then obtained.

[0090] To illustrate the process improvements of the present invention over the prior art and their effects, the following comparative examples were set up according to the preparation process of Example 1 to examine the changes in various properties of the aluminum alloy heat sink plates prepared after the conditions were changed.

[0091] Comparative Example 1

[0092] This comparative example is based on Example 1, using a traditional aluminum alloy sheet alloy formulation: Si: 0.2-0.6%; Mg: 0.6-1.5%; Cu: 0.8-1.5%; Mn: 0.10-0.2%; the balance being Al and trace impurities. Other steps are the same as in Example 1. The copper content of Comparative Example 1 is significantly higher than that of the above examples.

[0093] Comparative Example 2

[0094] This comparative example is based on Example 1, with the aluminum alloy sheet having the following alloy composition: Si: 0.12%, Cu: 0.17%, Fe: 0.12%, Ti: 0.015%, with the balance being Al and unavoidable impurities, wherein the Fe:Si mass ratio is 1. Other steps are the same as in Example 1.

[0095] Comparative Example 3

[0096] This comparative example is based on Example 1, except that in step (3), aluminum-titanium alloy is added to the melting furnace to refine the grains, and Al-5Ti-B wire is not added to the online flow channel outside the furnace. The other steps are the same as in Example 1.

[0097] Comparative Example 4

[0098] This comparative example is based on Example 1, except that in the heat treatment of step (5), the flat ingot is heated to 510°C in a furnace for 2 hours and then placed on a roller table to cool down to 430°C for rolling.

[0099] Comparative Example 5

[0100] This comparative example is based on Example 1, except that the final rolling temperature is controlled at 250-260°C during hot rolling in step (6). The other steps are the same as in Example 1.

[0101] Comparative Example 6

[0102] This comparative example is based on Example 1, except that in step (7), the hot-rolled plate at 360°C is placed on a rack with a flatness of no more than 1 mm and air-cooled for 6 hours. The other steps are the same as in Example 1.

[0103] Comparative Example 7

[0104] This comparative example is based on Example 1, except that in step (9), the artificial aging process was carried out at 280°C for 2 hours. The other steps are the same as in Example 1.

[0105] The aluminum alloy sheets prepared in Examples 1-4 and Comparative Examples 1-7 were subjected to performance tests, and the test results are shown in Table 1. (Table 1)

[0106]

[0107]

[0108] As shown in the table above, this invention reduces internal cracks in the billet and decreases the machining deformation rate of the finished product by controlling the iron-silicon ratio of the main impurity component in the melt to be no less than 1.9. This invention also incorporates the method of adding aluminum-titanium alloy and grain refiner both inside and outside the furnace (in the online runner), ensuring that the titanium content in the aluminum alloy ingot remains within a reasonable range, resulting in an ingot grain size ≤ Grade 1. This improves the mechanical properties, uniform microstructure, and refined grains of the aluminum alloy sheet for heat sinks. Simultaneously, the addition of a small amount of copper (0.12–0.17%) and control of the final rolling temperature at 330–360°C ensures that the internal grains of the aluminum alloy sheet are fully recrystallized grains. This improves the strength of the aluminum alloy heat sink sheet while eliminating the anisotropy of its internal mechanical properties, reducing internal stress, and ultimately obtaining a high-performance aluminum alloy heat sink sheet.

[0109] Furthermore, improvements to the pre-rolling heating process ensure uniform internal structure, consistent surface hardness, and balanced internal stress in aluminum alloy ingots. Optimization of the hot-rolled plate cooling method, the number of straightening cycles on the roll straightening machine, and innovative artificial aging heat treatment eliminate residual stress, stabilize part shape and dimensions, minimize internal stress in the plate, achieve uniform stress distribution within the material, and reduce sawing deformation rate. The surface hardness of the finished plate reaches 25-28 HB. In contrast, in the comparative example, when the surface hardness of the plate reaches above 40 HB, the internal stress is too high, and the sawing deformation rate is also high.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a high-performance aluminum alloy heat sink plate, characterized in that, include: S1. Prepare the required raw materials according to the composition requirements of aluminum alloy sheets; The mass composition of the aluminum alloy sheet is as follows: Si: 0.06-0.08%, Cu: 0.12-0.17%, Fe: 0.12-0.15%, Ti: 0.01-0.015%, with the balance being Al and unavoidable impurities, wherein the Fe:Si mass ratio is ≥1.90; wherein Al is provided by high-purity aluminum ingots, and Cu is provided by aluminum-copper alloys; S2. Clean and dry the surface of each raw material to ensure that the raw materials are free of moisture and impurities; S3. High-purity aluminum ingots are put into the melting furnace and heated to 730-750℃ at a rate of 8-10℃ / min until they are completely melted. S4. Add the preheated aluminum-copper alloy into the furnace and reduce the temperature to 650-680℃ at a rate of 3-5℃ / min to completely melt the aluminum-copper alloy. Hold the temperature for 1-1.5 hours while stirring and removing slag. S5. Add aluminum-titanium alloy into the furnace to refine the grains, and introduce nitrogen into the furnace for degassing and refining agent for refining to obtain aluminum alloy melt. S6. Add Al-5Ti-B wire or titanium-zirconium alloy into the online flow channel outside the furnace, and then control the temperature of the obtained aluminum alloy melt at 730-750℃ for casting. S7. Cut off the pouring gate and sprue head of the cast aluminum alloy ingot, and mill off the surface segregation layer. S8. Heat the milled aluminum alloy ingot to 450-470℃ and hold for ≥12h. Place it on the roller table and cool it to 400-420℃ at a rate of 3-5℃ / min before rolling. Control the rolling temperature to the finished thickness at 330-360℃. S9. Place the hot-rolled plate at 330-360℃ on a material rack with a flatness of no more than 1mm and allow it to air cool naturally. S10. Cut the cooled hot-rolled plate to length and then flatten it. S11. Stack the flat aluminum alloy sheets into the heat treatment furnace and keep them at 150-175℃ for ≥17h. Then, remove them from the furnace and air cool them to room temperature.

2. The preparation method according to claim 1, characterized in that, In S2, the temperature is raised to 120℃ at a rate of 10℃ / min and held for ≥2 hours for drying.

3. The preparation method according to claim 1, characterized in that, In S5, the degassing and refining time is 30 minutes.

4. The preparation method according to claim 1, characterized in that, In S6, the Al-5Ti-B wire is replaced with a Ti+Zr composite refining agent, which contains 0.032-0.037% Ti and 0.005-0.0075% Zr.

5. The preparation method according to claim 1, characterized in that, In S8, the milled aluminum alloy ingot is heated to 450-470℃ and held for 17 hours.

6. The preparation method according to claim 1, characterized in that, In S9, the time for the hot-rolled plate to cool to room temperature shall not be less than 72 hours.

7. The preparation method according to claim 1, characterized in that, In S9, when air cooling is performed on the material rack, stainless steel strips of 2.5-3.5*(10-20)*(1000-2000)mm are placed between the plates, with a spacing of ≤500mm.

8. The preparation method according to claim 1, characterized in that, In S10, the material is first sawn into strips, then leveled and straightened, and then straightened for 7 passes on a roller straightening machine.

9. The preparation method according to claim 1, characterized in that, In S11, the furnace temperature is first raised to 260℃ at a heating rate of 0.5℃ / min. The flat aluminum alloy plates are then stacked into the heat treatment furnace, cooled to 170±3℃ and held for 17-22 hours before being removed from the furnace.

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