High-power tooth radiator aluminum alloy and preparation method thereof

Abstract

The invention relates to the technical field of high-power tooth radiator aluminum alloy preparation, and discloses a high-power tooth radiator aluminum alloy and a preparation method thereof.The high-power tooth radiator aluminum alloy is composed of, by mass, 2% of aluminum, 0.8% of silicon, 0.4% of magnesium, 0.2% of copper, 0.15% of titanium, 0.02% of boron, 0.08% of zirconium, 0.05% of rare earth elements, 0.1% of zinc and 0.05% of manganese. Titanium, boron, zirconium and rare earth elements are added into aluminum alloy raw materials, the synergistic effect of the titanium, the boron, the zirconium and the rare earth elements serves as a heterogeneous nucleation core in the solidification process, grains are refined, columnar crystals are restrained from being formed, meanwhile, a double-flow casting technology is adopted, an outer-layer crystallizer is cooled through water, a large number of small equiaxed crystals are promoted to be generated, and a multi-direction extrusion technology is combined. And the trend of the columnar crystal is further broken, so that the grain orientation is uniform, and material waste and production loss caused by cracking are effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of aluminum alloy for high - multiple - tooth radiators, and particularly relates to an aluminum alloy for high - multiple - tooth radiators and a preparation method thereof. Background Art

[0002] The aluminum alloy for high - multiple - tooth radiators is a high - performance heat - dissipation material, which is widely used in fields such as electronic devices, automobiles, and machinery. The aluminum alloy has good thermal conductivity, can quickly conduct heat from the heat source to the surface of the radiator, and then dissipate the heat to the surrounding environment through air convection and other means. The high - multiple - tooth structure further increases the heat - dissipation area and improves the heat - dissipation efficiency. The density of the aluminum alloy is only one - third of that of steel, with light weight, which is convenient for installation and handling. Under the same heat - dissipation effect, the weight of the aluminum - alloy radiator is much lower than that of cast - iron or copper radiators. The aluminum - alloy radiator has high strength and stiffness, can withstand sufficient pressure even in a relatively thin state, and a dense oxide film can be formed on its surface, having good corrosion resistance and being suitable for various environments;

[0003] In the preparation process of the aluminum alloy for high - multiple - tooth radiators, the columnar crystals formed by the traditional casting process will extend along the direction of the principal stress during extrusion, resulting in longitudinal cracking. This is because the growth direction of the columnar crystals is inconsistent with the extrusion direction, causing stress concentration in the material during extrusion and thus triggering cracks.

[0004] To solve the above problems, a high - multiple - tooth radiator aluminum alloy and a preparation method thereof are proposed in this application. Summary of the Invention

[0005] The present invention provides a high - multiple - tooth radiator aluminum alloy and a preparation method thereof, which solve the problem that the columnar crystals formed by the traditional casting process in the related technology will extend along the direction of the principal stress during extrusion, resulting in longitudinal cracking.

[0006] The high - multiple - tooth radiator aluminum alloy provided by the present invention is composed of the following raw materials in mass percentages:

[0007] Aluminum 2 - 4%, silicon 0.8 - 1.2%, magnesium 0.4 - 0.6%, copper 0.2 - 0.4%, titanium 0.15 - 0.25%, boron 0.02 - 0.05%, zirconium 0.08 - 0.12%, rare - earth elements 0.05 - 0.10%, zinc 0.1 - 0.3%, manganese 0.05 - 0.10%.

[0008] A preparation method of a high - multiple - tooth radiator aluminum alloy, using the high - multiple - tooth radiator aluminum alloy as claimed in claim 1, comprises the following steps:

[0009] Step 1: Raw material pretreatment. Mix the main components of aluminum, silicon, magnesium, and copper in proportion and crush them to a particle size. Prepare master alloys from titanium, boron, zirconium, rare earth elements, zinc, and manganese refining agents.

[0010] Step 2: Layered melting. Use an intermediate frequency induction furnace to melt in two layers. The bottom layer is the matrix alloy of aluminum, silicon, magnesium, and copper, with a melting temperature of 720 - 740 °C. The upper layer is the master alloy of the refining agent, with a melting temperature of 700 - 720 °C, and stir for 10 - 15 minutes.

[0011] Step 3: Twin - stream casting. Use a double - crystallizer for casting. The outer crystallizer is cooled rapidly by water, and the inner crystallizer is protected by argon gas. Control the casting speed at 20 - 30 mm / min to obtain equiaxed crystal billets.

[0012] Step 4: Gradient heat treatment. Heat up to 480 °C and hold for 2 h, then cool down to 450 °C and hold for 1 h, and finally heat up to 500 °C and hold for 3 h. The gradient temperature promotes uniform recrystallization and eliminates casting stress.

[0013] Step 5: Multi - directional extrusion. Use a four - directional extruder, with an extrusion ratio of 15:1, an extrusion temperature of 420 - 440 °C, and rotate 30° for each extrusion direction to break the directionality of columnar crystals.

[0014] Step 6: Surface treatment. Remove the oxide scale by alkali washing, then neutralize with acid washing, and improve the surface finish by chemical polishing.

[0015] Step 7: Aging treatment. Perform step - by - step aging, hold at 120 °C for 4 h, 160 °C for 6 h, and 180 °C for 2 h.

[0016] Step 8: Precision gear cutting. Use a CNC gear - milling machine for gear cutting.

[0017] As a further optimized solution of the present invention, the raw material pretreatment in Step 1 specifically includes:

[0018] S1. Use electromagnetic stirring to remove inclusions in the aluminum melt, perform surface coating treatment on silicon and magnesium oxide elements, and control the particle size of the mixed raw materials between 2 - 5 mm by vibrating screening.

[0019] S2. Perform vacuum degassing treatment on copper and zinc heavy metal elements, add 0.01 - 0.03% of lithium as a deoxidizer, and use ultrasonic vibration to promote element pre - diffusion.

[0020] S3. Add rare earth elements in the form of aluminum - rare earth element master alloys, use nitrogen protection to prevent magnesium element burning loss, and control the hydrogen content of the raw materials after pretreatment to ≤0.15 ml / 100 g aluminum.

[0021] As a further optimized solution of the present invention, the layered melting in Step 2 specifically includes:

[0022] S1. The bottom layer is melted by a resistance furnace, the upper layer is melted by an induction furnace, a ceramic filter plate is arranged between the layers, and an Ar-CO2 mixed gas with a volume ratio of 9:1 is introduced during the melting process;

[0023] S2. The temperature difference between the upper and lower layers is controlled at 30-50 °C, mechanical stirring and electromagnetic stirring act alternately, and 0.05-0.1% of strontium is added as a modifier;

[0024] S3. The melting time is controlled within 45-60 minutes, an infrared thermometer is used to monitor the melt temperature in real time, and the melt is allowed to stand for 15 minutes before casting for melt purification.

[0025] As a further optimized scheme of the present invention, the double-flow casting in step three specifically includes:

[0026] S1. The outer crystallizer uses a graphite lining with a thickness of 3-5 mm, the inner crystallizer is filled with a He-Ne mixed gas with a pressure of 0.1-0.3 MPa, and a transverse magnetic field of 0.5-1.0 T is applied during the casting process;

[0027] S2. The cooling medium is an ethylene glycol aqueous solution with a volume concentration of 30-40%, the taper of the crystallizer is set to 1:50-1:100, and the casting speed is dynamically adjusted according to the diameter of the billet, formula: v = 0.02D 2 ;

[0028] S3. The surface of the billet is sprayed with a boron nitride release agent, a laser thickness gauge is used to monitor the thickness of the solidified layer in real time, and water quenching treatment is carried out immediately after casting, with the water temperature ≤ 25 °C.

[0029] As a further optimized scheme of the present invention, the gradient heat treatment in step four specifically includes:

[0030] S1. The heating rate is controlled at 5-8 °C / min, stepwise cooling is adopted between each temperature section, each step drops 5 °C, and dry air is introduced during the heat preservation process, with the dew point ≤ -40 °C;

[0031] S2. 0.02-0.04% of borax is added during the heat preservation stage at 480 °C, a hydrostatic pressure of 0.5-1.0 MPa is applied during the heat preservation at 450 °C, and a circulating oil bath is used for heating during the heat preservation at 500 °C;

[0032] S3. The total treatment time is controlled within 6-8 hours, gradient cooling is adopted after the heat treatment, with a drop of 20 °C per hour, and an X-ray diffractometer is used to monitor the phase transformation in real time during the treatment process.

[0033] As a further optimized scheme of the present invention, the multi-directional extrusion in step five specifically includes:

[0034] S1. Adopt a four-station rotary die with a rotation angle of 90°, dynamically adjust the extrusion speed according to the degree of deformation, and preheat the die to 380 - 400 °C before extrusion;

[0035] S2. The extrusion ratio decreases by 10 - 15% for each pass. Apply ultrasonic vibration during the extrusion process, with a frequency of 20 - 40 kHz. Use graphite emulsion as a lubricant with a concentration of 15 - 20%;

[0036] S3. Immediately perform water mist quenching after extrusion. Control the cross-sectional dimension accuracy of the extruded part within ±0.1 mm, and the total cumulative extrusion ratio reaches 25:1 - 30:1.

[0037] As a further optimized solution of the present invention, the surface treatment in step six specifically includes:

[0038] S1. Add 0.5 - 1.0% sodium gluconate to the alkali cleaning solution, control the pickling time within 30 - 60 seconds, and set the chemical polishing temperature at 45 - 55 °C;

[0039] S2. Adopt pulse current-assisted polishing with a current density of 5 - 10 A / dm 2 , form a passivation film with a thickness of 0.5 - 1.0 μm on the surface, and perform high-pressure water rinsing after treatment with a pressure of 5 - 8 MPa;

[0040] S3. Use laser cleaning to remove residual contaminants. Control the surface roughness Ra through abrasive flow machining, and immediately perform hot air drying after treatment at a temperature of 80 - 100 °C.

[0041] As a further optimized solution of the present invention, the aging treatment in step seven specifically includes:

[0042] S1. Introduce wet air during the 120 °C insulation stage with a humidity of 60 - 70%. Apply a compressive stress of 0.1 - 0.3 MPa during the 160 °C insulation, and use infrared radiation heating during the 180 °C insulation;

[0043] S2. Control the cooling rate between each stage within 15 - 20 °C / min, add 0.01 - 0.02% nickel as an aging accelerator, and dynamically adjust the total aging time according to on-line hardness detection;

[0044] S3. Perform cryogenic treatment after aging, maintain at -70 °C for 2 hours, use ultrasonic testing to detect the uniformity of the distribution of strengthening phases, and the Vickers hardness of the treated material reaches HV120 - 140.

[0045] As a further optimized solution of the present invention, the precision gear cutting in step eight specifically includes:

[0046] S1. Use a CBN tool with a rake angle of -5° to 0°, control the cutting speed at 150 - 200 m / min, and set the feed rate to 0.05 - 0.1 mm / z;

[0047] S2. The tooth profile correction amount is 0.8 - 0.9 times the theoretical value. During the machining process, use an internal cooling tool holder with a coolant pressure of 3 - 5 MPa, and perform laser strengthening treatment on the tooth surface with a power of 1 - 2 kW;

[0048] S3. Use a coordinate measuring machine to detect the tooth profile, control the pitch cumulative error within ±0.015 mm, and perform vibration aging after machining to eliminate residual stress.

[0049] The above technical solutions of the present invention have the following beneficial technical effects:

[0050] 1. By adding titanium, boron, zirconium, and rare earth elements to the aluminum alloy raw material, these elements work synergistically to act as heterogeneous nucleation cores during the alloy solidification process, refine the grains, and effectively inhibit the formation of columnar crystals. At the same time, adopt the double-flow casting process, where the outer crystallizer is cooled rapidly by passing water, and the cooling rate is ≥50 °C / s. This rapid cooling method promotes the formation of a large number of fine equiaxed crystals. Combined with the multi-directional extrusion process, the extrusion ratio is 15:1 and the extrusion interval rotates 30° in each direction, which can further break the possible columnar crystal trend, make the grain orientation more uniform, and reduce material waste and production losses caused by cracking;

[0051] 2. In the process of solving the cracking problem caused by columnar crystals, the present invention optimizes the aluminum alloy composition, adjusts the contents of silicon, magnesium, copper, zinc, and manganese, so that each element plays a synergistic role in the alloy. Among them, silicon improves the fluidity and wear resistance of the alloy, magnesium and copper form strengthening phases to enhance the strength of the alloy, zinc enhances the corrosion resistance, and manganese inhibits the harmful effects of iron and improves the machining performance. After the gradient heat treatment process, heat up to 480 °C and hold for 2 h, then cool down to 450 °C and hold for 1 h, and finally heat up to 500 °C and hold for 3 h, effectively eliminating the casting stress and promoting uniform recrystallization;

[0052] 3. In the raw material pretreatment stage, various raw materials are finely processed, including crushing the main components such as aluminum, silicon, magnesium, and copper to a particle size of ≤5 mm, performing surface coating treatment on easily oxidized elements, and removing inclusions in the aluminum melt by electromagnetic stirring, etc., which ensures the purity and uniformity of the raw materials. In the precision gear cutting link, using a CNC numerical control milling machine, with optimized tool parameters and a cooling and lubrication system, high-precision machining with a tooth pitch accuracy of ±0.02 mm and a tooth surface roughness Ra ≤ 0.4 μm can be achieved. At the same time, due to the effective solution of the columnar crystal problem in the previous process, during the extrusion and gear cutting processes, the processing stability is improved, the number of equipment shutdown and adjustment times is reduced, and the production efficiency is increased by about 30% compared with the traditional process. In the aging treatment stage, step-by-step aging is adopted to optimize the precipitation of strengthening phases, making the material properties stable, further ensuring the consistency of product processing quality, reducing the defective rate, and improving production efficiency and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a flowchart of a preparation method of an aluminum alloy for a high magnification gear radiator proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0055] Embodiment 1

[0056] As Figure 1 shown, an aluminum alloy for a high magnification gear radiator proposed by the present invention is composed of the following raw materials in mass percentages:

[0057] Aluminum 2%, silicon 0.8%, magnesium 0.4%, copper 0.2%, titanium 0.15%, boron 0.02%, zirconium 0.08%, rare earth elements 0.05%, zinc 0.1%, manganese 0.05%.

[0058] A preparation method of an aluminum alloy for a high magnification gear radiator, using the above-mentioned aluminum alloy for a high magnification gear radiator, includes the following steps:

[0059] Step 1: Raw material pretreatment, mixing and crushing the main components of aluminum, silicon, magnesium, and copper to a particle size, and making titanium, boron, zirconium, rare earth elements, zinc, and manganese refining agents into master alloys;

[0060] Step 2: Layered melting. Use an intermediate frequency induction furnace to melt in two layers. The bottom layer is the aluminum, silicon, magnesium, and copper matrix alloy, with a melting temperature of 720 - 740 °C. The upper layer is the refiner master alloy, with a melting temperature of 700 - 720 °C, and stir for 10 - 15 minutes.

[0061] Step 3: Twin - stream casting. Use a twin - mold casting method. The outer mold is cooled rapidly by passing water through it, and the inner mold is protected by passing argon gas through it. The casting speed is controlled at 20 - 30 mm / min to obtain an equiaxed crystal blank.

[0062] Step 4: Gradient heat treatment. Heat up to 480 °C and hold for 2 h, then cool down to 450 °C and hold for 1 h, and finally heat up to 500 °C and hold for 3 h. The gradient temperature promotes uniform recrystallization and eliminates casting stress.

[0063] Step 5: Multi - directional extrusion. Use a four - directional extruder, with an extrusion ratio of 15:1, an extrusion temperature of 420 - 440 °C, and rotate 30° at intervals for each extrusion direction to break the columnar crystal directionality.

[0064] Step 6: Surface treatment. Remove the oxide scale by alkaline washing, then neutralize with acid washing, and improve the surface finish by chemical polishing.

[0065] Step 7: Aging treatment. Perform step - by - step aging, hold at 120 °C for 4 h, 160 °C for 6 h, and 180 °C for 2 h.

[0066] Step 8: Precision gear cutting. Use a CNC gear - milling machine for gear cutting.

[0067] In this embodiment, the raw material pretreatment in Step 1 specifically includes:

[0068] S1. Use electromagnetic stirring to remove inclusions in the aluminum melt, perform surface coating treatment on silicon and magnesium oxide elements, and control the particle size of the mixed raw materials at 2 - 5 mm using vibrating screening.

[0069] S2. Perform vacuum degassing treatment on copper and zinc heavy metal elements, add 0.01 - 0.03% of lithium as a deoxidizer, and use ultrasonic vibration to promote element pre - diffusion.

[0070] S3. Add rare earth elements in the form of aluminum - rare earth element master alloy, use nitrogen protection to prevent magnesium element from burning loss, and control the hydrogen content of the pretreated raw materials at ≤0.15 ml / 100 g aluminum.

[0071] In this embodiment, the layered melting in Step 2 specifically includes:

[0072] S1. The bottom layer is melted using a resistance furnace, the upper layer is melted using an induction furnace, a ceramic filter plate is set between the layers, and an Ar - CO2 mixed gas with a volume ratio of 9:1 is passed through during the melting process.

[0073] S2. Control the temperature difference between the upper and lower layers at 30 - 50 °C, alternately use mechanical stirring and electromagnetic stirring, and add 0.05 - 0.1% of strontium as a modifier;

[0074] S3. Control the melting time within 45 - 60 minutes, use an infrared thermometer to monitor the melt temperature in real time, and let it stand for 15 minutes before pouring for melt purification.

[0075] In this embodiment, the double - flow casting in step three specifically includes:

[0076] S1. The outer mold uses a graphite lining with a thickness of 3 - 5 mm. The inner mold is filled with a He - Ne mixed gas with a pressure of 0.1 - 0.3 MPa, and a transverse magnetic field of 0.5 - 1.0 T is applied during the casting process;

[0077] S2. The cooling medium is an ethylene glycol aqueous solution with a volume concentration of 30 - 40%. The taper of the mold is set to 1:50 - 1:100, and the casting speed is dynamically adjusted according to the diameter of the billet. The formula is: v = 0.02D 2 ;

[0078] S3. Spray boron nitride release agent on the surface of the billet, use a laser thickness gauge to monitor the solidification layer thickness in real time, and immediately perform water quenching treatment after casting, with the water temperature ≤ 25 °C.

[0079] In this embodiment, the gradient heat treatment in step four specifically includes:

[0080] S1. Control the heating rate at 5 - 8 °C / min, use step - by - step cooling between each temperature section, with a 5 °C drop for each step. Dry air is introduced during the heat preservation process, and the dew point ≤ - 40 °C;

[0081] S2. Add 0.02 - 0.04% of borax during the heat preservation stage at 480 °C, apply a hydrostatic pressure of 0.5 - 1.0 MPa during the heat preservation at 450 °C, and use a circulating oil bath for heating during the heat preservation at 500 °C;

[0082] S3. Control the total treatment time within 6 - 8 hours, use gradient cooling after heat treatment, with a 20 °C drop per hour, and use an X - ray diffractometer to monitor the phase transformation in real time during the treatment process.

[0083] In this embodiment, the multi - directional extrusion in step five specifically includes:

[0084] S1. Use a four - station rotary die with a rotation angle of 90°. The extrusion speed is dynamically adjusted according to the degree of deformation, and the die is pre - heated to 380 - 400 °C before extrusion;

[0085] S2. The extrusion ratio decreases by 10 - 15% for each pass. Ultrasonic vibration is applied during the extrusion process, with a frequency of 20 - 40 kHz. Use graphite emulsion as a lubricant with a concentration of 15 - 20%;

[0086] S3. Immediately perform water mist quenching after extrusion. Control the cross-sectional dimension accuracy of the extruded part within ±0.1 mm, and the total extrusion ratio accumulatively reaches 25:1 - 30:1.

[0087] In this embodiment, the surface treatment in step six specifically includes:

[0088] S1. Add 0.5 - 1.0% sodium gluconate to the alkali cleaning solution. Control the pickling time within 30 - 60 seconds, and set the chemical polishing temperature at 45 - 55°C;

[0089] S2. Adopt pulse current-assisted polishing with a current density of 5 - 10 A / dm 2 . A passivation film with a thickness of 0.5 - 1.0 μm is formed on the surface. After treatment, perform high-pressure water rinsing with a pressure of 5 - 8 MPa;

[0090] S3. Use laser cleaning to remove residual contaminants. Control the surface roughness Ra through abrasive flow machining. Immediately perform hot air drying after treatment at a temperature of 80 - 100°C.

[0091] In this embodiment, the aging treatment in step seven specifically includes:

[0092] S1. Introduce wet air during the heat preservation stage at 120°C with a humidity of 60 - 70%. Apply a compressive stress of 0.1 - 0.3 MPa during heat preservation at 160°C, and use infrared radiation heating during heat preservation at 180°C;

[0093] S2. Control the cooling rate between each stage within 15 - 20°C / min. Add 0.01 - 0.02% nickel as an aging accelerator, and dynamically adjust the total aging time according to on-line hardness detection;

[0094] S3. Perform cryogenic treatment after aging, maintain at -70°C for 2 hours, and use ultrasonic testing to detect the uniformity of the distribution of strengthening phases. After treatment, the Vickers hardness of the material reaches HV120 - 140.

[0095] In this embodiment, the precision gear cutting in step eight specifically includes:

[0096] S1. Use a CBN tool with a rake angle of -5° to 0°. Control the cutting speed within 150 - 200 m / min, and set the feed rate at 0.05 - 0.1 mm / z;

[0097] S2. The tooth profile correction amount is 0.8 - 0.9 times the theoretical value. Use an internal cooling type tool holder during the machining process, with a coolant pressure of 3 - 5 MPa, and perform laser strengthening treatment on the tooth surface with a power of 1 - 2 kW;

[0098] S3. Use a coordinate measuring machine to detect the tooth profile. Control the cumulative pitch error within ±0.015 mm, and perform vibration aging to eliminate residual stress after machining.

[0099] Example 2

[0100] As Figure 1 shown, a high-ratio tooth radiator aluminum alloy proposed by the present invention is composed of raw materials in the following mass percentages:

[0101] Aluminum 3%, silicon 1.0%, magnesium 0.5%, copper 0.3%, titanium 0.2%, boron 0.03%, zirconium 0.1%, rare earth elements 0.08%, zinc 0.2%, manganese 0.08%.

[0102] A preparation method of a high-ratio tooth radiator aluminum alloy uses the above-mentioned high-ratio tooth radiator aluminum alloy and includes the following steps:

[0103] Step 1: Raw material pretreatment. The main components of aluminum, silicon, magnesium, and copper are mixed and crushed to a particle size, and titanium, boron, zirconium, rare earth elements, zinc, and manganese refiners are made into master alloys;

[0104] Step 2: Layered melting. Medium-frequency induction furnace is used for two-layer melting. The bottom layer is the aluminum, silicon, magnesium, and copper matrix alloy, and the melting temperature is 720 - 740°C. The upper layer is the refiner master alloy, and the melting temperature is 700 - 720°C. Stir for 10 - 15 minutes;

[0105] Step 3: Twin-belt casting. Twin crystallizers are used for casting. The outer crystallizer is cooled rapidly by water, and the inner crystallizer is protected by argon. The casting speed is controlled at 20 - 30 mm / min to obtain equiaxed crystal billets;

[0106] Step 4: Gradient heat treatment. Heat up to 480°C and hold for 2 h, then cool down to 450°C and hold for 1 h, and finally heat up to 500°C and hold for 3 h. The gradient temperature promotes uniform recrystallization and eliminates casting stress;

[0107] Step 5: Multi-directional extrusion. A four-directional extruder is used, the extrusion ratio is 15:1, the extrusion temperature is 420 - 440°C, and it rotates 30° at intervals for each extrusion direction to break the columnar crystal directionality;

[0108] Step 6: Surface treatment. Alkali washing is used to remove the oxide scale, then acid washing for neutralization, and chemical polishing to improve the surface finish;

[0109] Step 7: Aging treatment. Step-by-step aging, hold at 120°C for 4 h, 160°C for 6 h, and 180°C for 2 h;

[0110] Step 8: Precision tooth cutting. Use a CNC numerical control milling machine for tooth cutting.

[0111] In this embodiment, the raw material pretreatment in Step 1 specifically includes:

[0112] S1. Use electromagnetic stirring to remove inclusions in the aluminum melt, perform surface coating treatment on silicon and magnesium oxide elements, and use vibrating screening to control the particle size of the mixed raw materials between 2 - 5 mm;

[0113] S2. Perform vacuum degassing treatment on copper and zinc heavy metal elements, add 0.01 - 0.03% of lithium as a deoxidizer, and use ultrasonic vibration to promote element pre-diffusion;

[0114] S3. Add rare earth elements in the form of aluminum-rare earth element master alloy, use nitrogen protection to prevent magnesium element burning loss, and control the hydrogen content of the raw materials after pretreatment to ≤0.15 ml / 100 g of aluminum.

[0115] In this embodiment, the stratified melting in step two specifically includes:

[0116] S1. Use a resistance furnace for melting at the bottom layer and an induction furnace for melting at the upper layer. Set a ceramic filter plate between the layers, and introduce an Ar-CO2 mixed gas with a volume ratio of 9:1 during the melting process;

[0117] S2. Control the temperature difference between the upper and lower layers at 30 - 50 °C, use mechanical stirring and electromagnetic stirring alternately, and add 0.05 - 0.1% of strontium as a modifier;

[0118] S3. Control the melting time at 45 - 60 minutes, use an infrared thermometer to monitor the melt temperature in real time, and let it stand for 15 minutes before tapping for melt purification.

[0119] In this embodiment, the double-flow casting in step three specifically includes:

[0120] S1. The outer mold uses a graphite lining with a thickness of 3 - 5 mm. The inner mold introduces a He-Ne mixed gas with a pressure of 0.1 - 0.3 MPa, and applies a transverse magnetic field of 0.5 - 1.0 T during the casting process;

[0121] S2. The cooling medium is an ethylene glycol aqueous solution with a volume concentration of 30 - 40%. The taper of the mold is set at 1:50 - 1:100, and the casting speed is dynamically adjusted according to the diameter of the billet, formula: v = 0.02D 2 ;

[0122] S3. Spray boron nitride release agent on the surface of the billet, use a laser thickness gauge to monitor the thickness of the solidified layer in real time, and immediately perform water quenching treatment after casting, with the water temperature ≤25 °C.

[0123] In this embodiment, the gradient heat treatment in step four specifically includes:

[0124] S1. Control the heating rate at 5 - 8 °C / min, use stepwise cooling between each temperature section, with a 5 °C drop for each step, and introduce dry air during the heat preservation process, with the dew point ≤ -40 °C;

[0125] S2. Add 0.02 - 0.04% borax during the heat preservation stage at 480°C, apply a hydrostatic pressure of 0.5 - 1.0 MPa during heat preservation at 450°C, and use a circulating oil bath for heating during heat preservation at 500°C;

[0126] S3. Control the total treatment time within 6 - 8 hours, adopt gradient cooling after heat treatment, with a temperature drop of 20°C per hour, and use an X-ray diffractometer to monitor the phase transformation in real time during the treatment process.

[0127] In this embodiment, the multi-directional extrusion in step five specifically includes:

[0128] S1. Adopt a four-station rotary die, with a rotation angle of 90°, dynamically adjust the extrusion speed according to the degree of deformation, and preheat the die to 380 - 400°C before extrusion;

[0129] S2. The extrusion ratio decreases by 10 - 15% for each pass. Apply ultrasonic vibration during the extrusion process, with a frequency of 20 - 40 kHz, and use graphite emulsion as a lubricant with a concentration of 15 - 20%;

[0130] S3. Immediately perform water mist quenching after extrusion, control the cross-sectional dimension accuracy of the extruded part within ±0.1 mm, and the total extrusion ratio accumulates to 25:1 - 30:1.

[0131] In this embodiment, the surface treatment in step six specifically includes:

[0132] S1. Add 0.5 - 1.0% sodium gluconate to the alkali cleaning solution, control the pickling time within 30 - 60 seconds, and set the chemical polishing temperature at 45 - 55°C;

[0133] S2. Adopt pulse current-assisted polishing, with a current density of 5 - 10 A / dm 2 , form a passivation film with a thickness of 0.5 - 1.0 μm on the surface, and perform high-pressure water rinsing after treatment, with a pressure of 5 - 8 MPa;

[0134] S3. Use laser cleaning to remove residual contaminants, control the surface roughness Ra through abrasive flow machining, and immediately perform hot air drying after treatment, with a temperature of 80 - 100°C.

[0135] In this embodiment, the aging treatment in step seven specifically includes:

[0136] S1. Pass in wet air during the heat preservation stage at 120°C, with a humidity of 60 - 70%, apply a compressive stress of 0.1 - 0.3 MPa during heat preservation at 160°C, and use infrared radiation heating during heat preservation at 180°C;

[0137] S2. Control the cooling rate between each stage within 15 - 20°C / min, add 0.01 - 0.02% nickel as an aging accelerator, and dynamically adjust the total aging time according to the on-line hardness detection;

[0138] S3. After aging, cryogenic treatment is carried out, maintaining at -70°C for 2 hours. Ultrasonic testing is used to detect the uniformity of the distribution of strengthening phases. After treatment, the Vickers hardness of the material reaches HV120 - 140.

[0139] In this embodiment, the precise gear cutting in step eight specifically includes:

[0140] S1. Use a CBN tool with a rake angle of -5° to 0°, control the cutting speed at 150 - 200 m / min, and set the feed rate to 0.05 - 0.1 mm / z;

[0141] S2. The tooth profile correction amount is 0.8 - 0.9 times the theoretical value. During the machining process, an internal cooling type tool holder is used, the coolant pressure is 3 - 5 MPa, and laser strengthening treatment is carried out on the tooth surface with a power of 1 - 2 kW;

[0142] S3. Use a coordinate measuring machine to detect the tooth profile, control the cumulative pitch error within ±0.015 mm, and perform vibration aging after machining to eliminate residual stress.

[0143] Example Three

[0144] As Figure 1 shown, a high - magnification tooth radiator aluminum alloy proposed by the present invention is composed of raw materials with the following mass percentages:

[0145] Aluminum 4%, silicon 1.2%, magnesium 0.6%, copper 0.4%, titanium 0.25%, boron 0.05%, zirconium 0.12%, rare earth elements 0.10%, zinc 0.3%, manganese 0.10%.

[0146] A preparation method of a high - magnification tooth radiator aluminum alloy uses the above - mentioned high - magnification tooth radiator aluminum alloy and includes the following steps:

[0147] Step 1: Pretreatment of raw materials. Mix the main components of aluminum, silicon, magnesium, and copper in proportion and crush them to a particle size. Make intermediate alloys from titanium, boron, zirconium, rare earth elements, zinc, and manganese as grain refiners;

[0148] Step 2: Layered melting. Use an intermediate - frequency induction furnace to melt in two layers. The bottom layer is the matrix alloy of aluminum, silicon, magnesium, and copper with a melting temperature of 720 - 740°C, and the upper layer is the intermediate alloy of grain refiners with a melting temperature of 700 - 720°C. Stir for 10 - 15 minutes;

[0149] Step 3: Twin - stream casting. Use a double - crystallizer for casting. The outer crystallizer is cooled rapidly by water, and the inner crystallizer is protected by argon. Control the casting speed at 20 - 30 mm / min to obtain an equiaxed crystal blank;

[0150] Step 4: Gradient heat treatment. Heat up to 480°C and hold for 2 h, then cool down to 450°C and hold for 1 h, and finally heat up to 500°C and hold for 3 h. The gradient temperature promotes uniform recrystallization and eliminates casting stress;

[0151] Step 5: Multi-directional extrusion. Use a four-directional extruder with an extrusion ratio of 15:1, an extrusion temperature of 420 - 440 °C, and rotate 30° at intervals for each direction of extrusion to break the columnar crystal directionality.

[0152] Step 6: Surface treatment. Remove the oxide scale by alkaline washing, then neutralize with acid washing, and improve the surface finish by chemical polishing.

[0153] Step 7: Aging treatment. Perform step-by-step aging, keep at 120 °C for 4 h, 160 °C for 6 h, and 180 °C for 2 h.

[0154] Step 8: Precision gear cutting. Use a CNC gear milling machine for gear cutting.

[0155] In this embodiment, the raw material pretreatment in Step 1 specifically includes:

[0156] S1. Use electromagnetic stirring to remove inclusions in the aluminum melt, perform surface coating treatment on silicon and magnesium oxide elements, and control the particle size of the mixed raw materials between 2 - 5 mm by vibrating screening.

[0157] S2. Perform vacuum degassing treatment on copper and zinc heavy metal elements, add 0.01 - 0.03% of lithium as a deoxidizer, and use ultrasonic vibration to promote element pre-diffusion.

[0158] S3. Add rare earth elements in the form of an aluminum-rare earth element master alloy, use nitrogen protection to prevent magnesium element burning loss, and control the hydrogen content of the raw materials after pretreatment to ≤0.15 ml / 100 g of aluminum.

[0159] In this embodiment, the layered melting in Step 2 specifically includes:

[0160] S1. The bottom layer is melted by a resistance furnace, the upper layer is melted by an induction furnace, a ceramic filter plate is set between the layers, and an Ar-CO2 mixed gas with a volume ratio of 9:1 is introduced during the melting process.

[0161] S2. Control the temperature difference between the upper and lower layers at 30 - 50 °C, alternately use mechanical stirring and electromagnetic stirring, and add 0.05 - 0.1% of strontium as a modifier.

[0162] S3. Control the melting time at 45 - 60 minutes, use an infrared thermometer to monitor the melt temperature in real time, and let it stand for 15 minutes before pouring for melt purification.

[0163] In this embodiment, the double-flow casting in Step 3 specifically includes:

[0164] S1. The outer crystallizer uses a graphite lining with a thickness of 3 - 5 mm, the inner crystallizer is filled with a He-Ne mixed gas with a pressure of 0.1 - 0.3 MPa, and a transverse magnetic field of 0.5 - 1.0 T is applied during the casting process.

[0165] S2. The cooling medium is an ethylene glycol aqueous solution with a volume concentration of 30 - 40%. The taper of the mold is set to 1:50 - 1:100, and the casting speed is dynamically adjusted according to the diameter of the billet. The formula is: v = 0.02D 2 ;

[0166] S3. Spray boron nitride mold release agent on the surface of the billet, use a laser thickness gauge to monitor the thickness of the solidified layer in real time, and immediately perform water quenching treatment after casting. The water temperature ≤ 25°C.

[0167] In this embodiment, the gradient heat treatment in step four specifically includes:

[0168] S1. The heating rate is controlled at 5 - 8°C / min, and stepped cooling is used between each temperature section, with a 5°C drop for each step. Dry air is introduced during the heat preservation process, and the dew point ≤ -40°C;

[0169] S2. Add 0.02 - 0.04% borax during the heat preservation stage at 480°C, apply a hydrostatic pressure of 0.5 - 1.0 MPa during heat preservation at 450°C, and use a circulating oil bath for heating during heat preservation at 500°C;

[0170] S3. The total treatment time is controlled within 6 - 8 hours, and gradient cooling is used after heat treatment, with a 20°C drop per hour. An X-ray diffractometer is used to monitor the phase transformation in real time during the treatment process.

[0171] In this embodiment, the multi-directional extrusion in step five specifically includes:

[0172] S1. Use a four-station rotary die with a rotation angle of 90°. The extrusion speed is dynamically adjusted according to the degree of deformation, and the die is preheated to 380 - 400°C before extrusion;

[0173] S2. The extrusion ratio decreases by 10 - 15% for each pass. Ultrasonic vibration is applied during the extrusion process, with a frequency of 20 - 40 kHz. Graphite emulsion is used as a lubricant with a concentration of 15 - 20%;

[0174] S3. Immediately perform water mist quenching after extrusion. The dimensional accuracy of the cross-section of the extruded part is controlled within ±0.1 mm, and the total extrusion ratio accumulates to 25:1 - 30:1.

[0175] In this embodiment, the surface treatment in step six specifically includes:

[0176] S1. Add 0.5 - 1.0% sodium gluconate to the alkali washing solution. The pickling time is controlled within 30 - 60 seconds, and the chemical polishing temperature is set to 45 - 55°C;

[0177] S2. Use pulsed current-assisted polishing with a current density of 5 - 10 A / dm 2, a passivation film with a thickness of 0.5 - 1.0 μm is formed on the surface, and after treatment, high-pressure water rinsing is carried out with a pressure of 5 - 8 MPa;

[0178] S3. Use laser cleaning to remove residual contaminants. The surface roughness Ra is controlled by abrasive flow machining, and hot air drying is carried out immediately after treatment at a temperature of 80 - 100 °C.

[0179] In this embodiment, the aging treatment in step seven specifically includes:

[0180] S1. Wet air is introduced during the heat preservation stage at 120 °C with a humidity of 60 - 70%. A compressive stress of 0.1 - 0.3 MPa is applied during the heat preservation at 160 °C, and infrared radiation heating is used during the heat preservation at 180 °C;

[0181] S2. The cooling rate between each stage is controlled at 15 - 20 °C / min, 0.01 - 0.02% of nickel is added as an aging accelerator, and the total aging time is dynamically adjusted according to on-line hardness detection;

[0182] S3. After aging, cryogenic treatment is carried out, maintained at -70 °C for 2 hours, and ultrasonic testing is used to detect the uniformity of the distribution of strengthening phases. The Vickers hardness of the treated material reaches HV120 - 140.

[0183] In this embodiment, the precision gear cutting in step eight specifically includes:

[0184] S1. Use a CBN tool with a rake angle of -5° to 0°, control the cutting speed at 150 - 200 m / min, and set the feed rate to 0.05 - 0.1 mm / z;

[0185] S2. The tooth profile correction amount is 0.8 - 0.9 times the theoretical value. During the machining process, an internal cooling tool holder is used, the coolant pressure is 3 - 5 MPa, and laser strengthening treatment is carried out on the tooth surface with a power of 1 - 2 kW;

[0186] S3. Use a coordinate measuring machine to detect the tooth profile, control the cumulative pitch error within ±0.015 mm, and carry out vibration aging to eliminate residual stress after machining

[0187] Select the finished products of Example 1, Example 2 and Example 3 for performance testing, and the results are as follows:

[0188]

[0189]

[0190] The specific working principle of the present invention is as follows:

[0191] Mix the main components of aluminum, silicon, magnesium, and copper in proportion and crush them to a particle size. Prepare master alloys from titanium, boron, zirconium, rare earth elements, zinc, and manganese refiners. Use an intermediate frequency induction furnace to melt in two layers. The bottom layer is the aluminum, silicon, magnesium, and copper matrix alloy with a melting temperature of 720 - 740 °C. The upper layer is the master alloy of the refiner with a melting temperature of 700 - 720 °C. Stir for 10 - 15 minutes, then use a double mold casting method. The outer mold is cooled rapidly by passing water, and the inner mold is protected by passing argon. Control the casting speed at 20 - 30 mm / min to obtain an equiaxed crystal blank. Perform gradient heat treatment by heating to 480 °C and holding for 2 h, then cooling to 450 °C and holding for 1 h, and finally heating to 500 °C and holding for 3 h. The gradient temperature promotes uniform recrystallization and eliminates casting stress. Perform multi-directional extrusion using a four-directional extruder with an extrusion ratio of 15:1 and an extrusion temperature of 420 - 440 °C. Rotate 30° at intervals for each extrusion direction to break the directionality of columnar crystals. Then remove the oxide scale by alkaline washing, followed by acid washing for neutralization and chemical polishing to improve the surface finish. Then perform step aging by holding at 120 °C for 4 h, 160 °C for 6 h, and 180 °C for 2 h. Finally, use a CNC gear milling machine to cut the teeth.

[0192] It should be understood that the above specific embodiments of the present invention are only used for exemplary illustration or explanation of the principles of the present invention and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all variations and modification examples that fall within the scope and boundaries of the appended claims or equivalent forms of such scope and boundaries.

Claims

1. A high-ratio tooth aluminum alloy radiator, characterized in that, It consists of raw materials with the following mass percentages: Aluminum 2 - 4%, silicon 0.8 - 1.2%, magnesium 0.4 - 0.6%, copper 0.2 - 0.4%, titanium 0.15 - 0.25%, boron 0.02 - 0.05%, zirconium 0.08 - 0.12%, rare earth elements 0.05 - 0.10%, zinc 0.1 - 0.3%, manganese 0.05 - 0.10%.

2. A preparation method of an aluminum alloy for a high-fold tooth radiator, using the aluminum alloy for a high-fold tooth radiator as claimed in claim 1, characterized in that, It includes the following steps: Step 1: Pretreatment of raw materials. Mix the main components of aluminum, silicon, magnesium, and copper proportionally and crush them to a particle size. Make master alloys from titanium, boron, zirconium, rare earth elements, zinc, and manganese refiner. Step 2: Layered melting. Use an intermediate frequency induction furnace to melt in two layers. The bottom layer is the matrix alloy of aluminum, silicon, magnesium, and copper, with a melting temperature of 720 - 740 °C. The upper layer is the master alloy of the refiner, with a melting temperature of 700 - 720 °C. Stir for 10 - 15 minutes. Step 3: Double - flow casting. Use a double - crystallizer for casting. The outer crystallizer is cooled rapidly by passing water, and the inner crystallizer is protected by passing argon. Control the casting speed at 20 - 30 mm / min to obtain an equiaxed crystal blank. Step 4: Gradient heat treatment. Heat up to 480 °C and hold for 2 h, then cool down to 450 °C and hold for 1 h, and finally heat up to 500 °C and hold for 3 h. The gradient temperature promotes uniform recrystallization and eliminates casting stress. Step 5: Multi - directional extrusion. Use a four - directional extruder with an extrusion ratio of 15:1 and an extrusion temperature of 420 - 440 °C. Rotate 30° at intervals for each extrusion direction to break the columnar crystal directionality. Step 6: Surface treatment. Remove the oxide scale by alkaline washing, then neutralize with acid washing, and improve the surface finish by chemical polishing. Step 7: Aging treatment. Perform step - by - step aging, hold at 120 °C for 4 h, 160 °C for 6 h, and 180 °C for 2 h. Step 8: Precision gear cutting. Use a CNC numerical control gear milling machine for gear cutting.

3. The preparation method of a high-ratio tooth heat sink aluminum alloy according to claim 2, wherein, The raw material pretreatment in the above - mentioned Step 1 specifically includes: S1. Use electromagnetic stirring to remove inclusions in the aluminum melt, perform surface coating treatment on silicon and magnesium oxide elements, and control the particle size of the mixed raw materials between 2 - 5 mm by vibration screening. S2. Perform vacuum degassing treatment on copper and zinc heavy metal elements, add 0.01 - 0.03% of lithium as a deoxidizer, and use ultrasonic vibration to promote element pre - diffusion. S3. Add rare earth elements in the form of aluminum - rare earth element master alloy, use nitrogen protection to prevent magnesium element burning loss, and control the hydrogen content of the pretreated raw materials at ≤0.15 ml / 100 g of aluminum.

4. The preparation method of a high-ratio tooth heat sink aluminum alloy according to claim 3, wherein The layered melting in the above - mentioned Step 2 specifically includes: S1. The bottom layer is melted by a resistance furnace, and the upper layer is melted by an induction furnace. A ceramic filter plate is set between the layers, and an Ar - CO2 mixed gas with a volume ratio of 9:1 is introduced during the melting process. S2. Control the temperature difference between the upper and lower layers at 30 - 50 °C, use mechanical stirring and electromagnetic stirring alternately, and add 0.05 - 0.1% of strontium as a modifier. S3. Control the melting time at 45 - 60 minutes, use an infrared thermometer to monitor the melt temperature in real - time, and let it stand for 15 minutes before tapping for melt purification.

5. The preparation method of a high-ratio tooth heat sink aluminum alloy according to claim 4, characterized in that The double - flow casting in the above - mentioned Step 3 specifically includes: S1. The outer crystallizer uses a graphite lining with a thickness of 3 - 5 mm. The inner crystallizer is filled with a He-Ne mixed gas at a pressure of 0.1 - 0.3 MPa, and a transverse magnetic field of 0.5 - 1.0 T is applied during the casting process. S2. The cooling medium is an ethylene glycol aqueous solution with a volume concentration of 30 - 40%. The taper of the crystallizer is set to 1:50 - 1:100, and the casting speed is dynamically adjusted according to the diameter of the billet. The formula is: v = 0.02D 2 ; S3. The surface of the billet is sprayed with a boron nitride release agent. A laser thickness gauge is used to monitor the thickness of the solidified layer in real time, and water quenching treatment is carried out immediately after casting, with the water temperature ≤ 25°C.

6. The preparation method of a high-ratio tooth radiator aluminum alloy according to claim 5, characterized in that, The gradient heat treatment in step four specifically includes: S1. The heating rate is controlled at 5 - 8°C / min. Stepwise cooling is adopted between each temperature section, with a 5°C drop for each step. Dry air is introduced during the heat preservation process, and the dew point ≤ -40°C. S2. 0.02 - 0.04% borax is added during the heat preservation stage at 480°C. A hydrostatic pressure of 0.5 - 1.0 MPa is applied during the heat preservation at 450°C, and a circulating oil bath is used for heating during the heat preservation at 500°C. S3. The total treatment time is controlled within 6 - 8 hours. Gradient cooling is adopted after the heat treatment, with a 20°C drop per hour. An X-ray diffractometer is used to monitor the phase transformation in real time during the treatment process.

7. The preparation method of a high-ratio tooth heat sink aluminum alloy according to claim 6, characterized in that, The multi-directional extrusion in step five specifically includes: S1. A four-station rotary die is used, with a rotation angle of 90°. The extrusion speed is dynamically adjusted according to the degree of deformation. The die is preheated to 380 - 400°C before extrusion. S2. The extrusion ratio decreases by 10 - 15% for each pass. Ultrasonic vibration is applied during the extrusion process, with a frequency of 20 - 40 kHz. Graphite emulsion is used as a lubricant, with a concentration of 15 - 20%. S3. Water mist quenching is carried out immediately after extrusion. The dimensional accuracy of the cross-section of the extruded part is controlled within ±0.1 mm, and the total extrusion ratio accumulates to 25:1 - 30:

1.

8. The preparation method of a high-ratio-tooth radiator aluminum alloy according to claim 7, characterized in that The surface treatment in step six specifically includes: S1. 0.5 - 1.0% sodium gluconate is added to the alkali washing solution. The pickling time is controlled within 30 - 60 seconds, and the chemical polishing temperature is set at 45 - 55°C. S2. Use pulse current-assisted polishing with a current density of 5 - 10 A / dm 2 , and a passivation film with a thickness of 0.5 - 1.0 μm is formed on the surface. After treatment, high-pressure water flushing is carried out with a pressure of 5 - 8 MPa; S3. Laser cleaning is used to remove residual contaminants. The surface roughness Ra is controlled by abrasive flow machining, and hot air drying is carried out immediately after the treatment, with a temperature of 80 - 100°C.

9. The preparation method of a high-ratio tooth heat sink aluminum alloy according to claim 8, characterized in that The aging treatment in step seven specifically includes: S1. Wet air is introduced during the heat preservation stage at 120°C, with a humidity of 60 - 70%. A compressive stress of 0.1 - 0.3 MPa is applied during the heat preservation at 160°C, and infrared radiation heating is used during the heat preservation at 180°C. S2. The cooling rate between each stage is controlled at 15 - 20°C / min. 0.01 - 0.02% nickel is added as an aging accelerator, and the total aging time is dynamically adjusted according to the online hardness detection. S3. Deep cryogenic treatment is carried out after aging, maintaining at -70°C for 2 hours. Ultrasonic testing is used to detect the uniformity of the distribution of the strengthening phase. The Vickers hardness of the treated material reaches HV120 - 140.

10. The preparation method of a high-ratio tooth heat sink aluminum alloy according to claim 9, characterized in that, The precision gear cutting in step eight specifically includes: S1. A CBN tool is used, with a rake angle of -5° to 0°. The cutting speed is controlled at 150 - 200 m / min, and the feed rate is set at 0.05 - 0.1 mm / z. S2. The tooth profile correction amount is 0.8 - 0.9 times the theoretical value. An internal cooling type tool holder is used during the machining process, with a coolant pressure of 3 - 5 MPa. Laser strengthening treatment is carried out on the tooth surface, with a power of 1 - 2 kW. S3. Use a coordinate measuring machine to perform tooth profile detection, control the pitch cumulative error within ±0.015 mm, and perform vibration aging after machining to eliminate residual stress.

Images