WO2023035831A1

WO2023035831A1 - Aluminum alloy for extrusion, and preparation method therefor

Info

Publication number: WO2023035831A1
Application number: PCT/CN2022/110595
Authority: WO
Inventors: 赵立洋; 张桓; 乔恒; 段妍彤; 张军; 金榕; 章安楠
Original assignee: 江苏亨通电力特种导线有限公司
Priority date: 2021-09-08
Filing date: 2022-08-05
Publication date: 2023-03-16
Also published as: CN113846249B; CN113846249A

Abstract

The present invention relates to an aluminum alloy for extrusion. The components of the aluminum alloy and the mass percentage of each component comprise: 0.1-0.2% of Si, 0.15-0.25% of Fe, 1.8-2.4% of Mn, 0.05-0.18% of Zn, 0.03-0.06% of Er, 0.008-0.04% of Ti, 0.04-0.08% of Be, and 0.01-0.02% of V, with the balance being Al and inevitable impurities, wherein the total amount of the impurities is not more than 0.015%. The aluminum alloy is prepared by means of process steps of smelting, alloying, refining, molten-aluminum online treatment, continuous casting, continuous rolling, cooling and take-up, annealing treatment, etc. The aluminum alloy of the present invention is significantly improved in terms of corrosion resistance, material strength, fluidity and structure continuity, such that the pressure-bearing capacity of a prepared extrusion material is significantly improved, and the service life thereof is prolonged.

Description

Aluminum alloy for extrusion and preparation method thereof

technical field

The invention relates to the field of aluminum alloy die-casting processing, in particular to an aluminum alloy for extrusion and a preparation method thereof.

Background technique

Aluminum alloy extrusion products are widely used in automobiles, airplanes, home appliances and other fields. In the process of continuous extrusion of aluminum alloy to produce condensing flat tubes, the processing cost due to die loss accounts for 30% of the total cost, and the average production of 3.5 tons of extruded products There will be different degrees of damage to the compression mold, and a new mold needs to be replaced. Therefore, how to extend the life of the extrusion die has become an urgent problem to be solved. Existing aluminum alloy materials have poor fluidity and ductility, and wall breakage often occurs when extruding thin-walled products, resulting in cost losses. In addition, there are also problems such as poor structural continuity, poor corrosion resistance, and coarse grains leading to poor toughness of aluminum alloy materials. Therefore, there is still a need for an aluminum alloy material to improve the extrusion performance of the material, which is suitable for extrusion products with complex structures or thin-wall structures, and prolongs the service life of extrusion dies.

Contents of the invention

In order to solve the above technical problems, the present invention provides an aluminum alloy for extrusion and a preparation method thereof, which have significantly improved corrosion resistance, material strength, fluidity and tissue continuity.

The present invention claims to protect an aluminum alloy for extrusion, its components and the mass percentage of each component are: Si 0.1-0.2%, Fe 0.15-0.25%, Mn 1.8-2.4%, Zn 0.05-0.18%, Er 0.03 -0.06%, Ti 0.008-0.04%, Be 0.04-0.08%, V 0.01-0.02%, the rest are Al and unavoidable impurities, and the total amount of impurities does not exceed 0.015%.

Preferably, the components of the aluminum alloy for extrusion and the mass percent of each component are: Si 0.18%, Fe 0.23%, Mn 2.23%, Zn 0.14%, Er 0.05%, Ti 0.02%, Be 0.06%, V 0.015 %, the rest is Al and unavoidable impurities, the total amount of impurities is not more than 0.015%.

The preparation method of aluminum alloy for extrusion of the present invention comprises the following steps:

S1: Add aluminum alloy with a purity of not less than 99.7% into a melting furnace to heat and melt, keep it warm at 780-800°C, blow in refining agent, and conduct a refining with nitrogen or argon to obtain the first aluminum liquid;

S2: Add an intermediate alloy to the first aluminum liquid in the holding furnace, stir for 25-35 minutes, and obtain the second aluminum liquid; wherein, the temperature of the holding furnace is 780-800°C, and the intermediate alloy is one or more types, containing Si , Fe, Mn, Zn, Er, Ti, Be and V;

S3: After the composition of the second aluminum liquid is qualified, the refining agent is blown in, the second refining is carried out with nitrogen or argon, and the slag is removed after standing to obtain the third aluminum liquid; Furnace 20-30min after dosing, refining temperature is 780-800℃;

S4: The third aluminum liquid is poured through the holding furnace, fed with AlTiC wire before entering the degassing box, and then degassed and double-stage filtered to obtain the fourth aluminum liquid;

S5: Carry out continuous casting of the fourth molten aluminum, and install a casting filter at the gate; wherein, the casting temperature is 710-720°C, the casting speed is 6.5-7.5t/h, the cooling water temperature is 25-35°C, and the billet is discharged The temperature is 520-550°C;

S6: rolling the slab obtained by continuous casting in S5 to obtain an aluminum rod; wherein, the rolling temperature is 510-540°C, and the finishing rolling temperature is 200-300°C;

S7: Cool down the aluminum rod to 60-80°C, blow it dry and take it up, then raise the temperature to 450-460°C within 7-9 hours, keep it warm for 88-100 hours, and cool it to 20-30°C with the furnace to obtain extrusion aluminum alloy.

At present, the medium-strength aluminum alloy materials used for extrusion in the industry mainly use Mn as the main element. Mn has the advantages of improving strength and corrosion resistance of materials, but there are the following problems: (1) High slag content, extrusion The material has very strict requirements on the slag content of the structure. During the extrusion process, these impurities will form hard spots, which will increase the wear of the mold, and will destroy the continuity of the structure and affect the quality of the extruded product; (2) The structure is not uniform , High manganese element is easy to segregate, grain growth is uneven after annealing, material properties are unstable, aluminum sticking and wall breaking are easy to occur during extrusion, which reduces mold life and product quality. Therefore, the manganese content in the aluminum alloy material should not be too high, but the lower manganese content will lead to poor corrosion resistance. The present invention obtains a high-strength, high-fluidity, high-ductility and corrosion-resistant aluminum alloy material by improving the raw material composition and proportion of the aluminum alloy, and cooperating with the production process and heat treatment process.

Further, in step S1, the time for one refining is 35-45 minutes.

Further, in step S1 or S3, a refining agent is added at a rate of 2-3 kg/t of aluminum liquid.

Further, in step S4, in the two-stage filtration, the pore size of the second filter is 60 mesh, and the pore size of the first filter is smaller than 60 mesh, preferably 40 mesh.

Further, in step S5, the speed of feeding the AlTiC wire is 1.5-2.0 m/min. AlTiC is selected as the refiner to avoid the formation of hard phase, thereby reducing the loss of the die during the extrusion process and increasing the continuity of the product. Within this speed range, the titanium content in the molten aluminum can be kept fluctuating within 0.008-0.04%.

Further, in step S5, horizontal casting is performed on the fourth molten aluminum.

Further, in step S5, the pore size of the casting filter is 16 mesh.

Further, in step S6, the flow rate of the rolling emulsion is 35-38 m ³ /h, the pressure is 180-200 kPa, and the final rolling temperature can be adjusted by the flow rate and pressure of the rolling emulsion.

Further, in step S7, keep warm for 90-96h.

Further, after each step, stand still for 35-45 minutes to precipitate impurities in the aluminum liquid.

The present invention also claims extruded products prepared using the aforementioned aluminum alloys.

By means of the above solution, the present invention has at least the following advantages:

(1) Mn can improve the corrosion resistance of aluminum alloys. Its maximum solid solubility in aluminum is 1.82%. Excessive Mn content can easily lead to intragranular segregation. The content of Mn in the medium can achieve corrosion resistance. By adding Fe, it can form FeMnAl ₆ phase with Mn, reduce the solid solution of Mn in the aluminum matrix, and improve the ductility of the alloy. At the same time, cooperate with Zn and Er to further reduce the solid solution of Mn And reduce the segregation phenomenon, refine the coarse phase in the structure, and significantly improve the mechanical properties of the material.

(2) The present invention matches the heat treatment process of the present invention by adding Er, Si, and Be to heat treatment at low temperature for a long time, so that the compound dissolved in the aluminum matrix is slowly precipitated, the amount of manganese element precipitation is promoted, and the growth of the precipitated phase is suppressed at the same time. Large, to realize the fine and dispersed distribution of the second phase, improve the extrusion fluidity of the alloy material, avoid the coarse grains caused by high temperature annealing, and provide an alloy material with excellent toughness.

(3) When the aluminum alloy material of the present invention is produced, refining is carried out in both the smelting furnace and the holding furnace, two-stage filtration is carried out after wire feeding, and a casting filter screen is set, because the aluminum liquid will churn during the process from the chute to the ladle Phenomenon, resulting in scale and brought into the billet through the aluminum liquid, forming large impurities, the present invention can eliminate the interference of these impurities.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the preferred embodiments of the present invention are described below with detailed drawings.

Description of drawings

In order to make the content of the present invention more clearly understood, the present invention will be further described in detail below according to the specific embodiments of the present invention and in conjunction with the accompanying drawings.

Figure 1 shows the aluminum alloys prepared in Example 1 and Comparative Examples 2, 8, and 9.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it, but the examples given are not intended to limit the present invention.

Example 1

The components of aluminum alloy for extrusion and the mass percentage of each component are: Si 0.18%, Fe 0.23%, Mn 2.23%, Zn 0.14%, Er 0.05%, Ti 0.02%, Be 0.06%, V 0.015%, the rest Al and unavoidable impurities, the total amount of impurities is not more than 0.015%.

The preparation method of aluminum alloy for extrusion comprises the following steps:

S1: Put the remelted aluminum ingot of Al99.70 into the smelting furnace and heat it to melt, keep it warm at 795°C, add refining agent to the melt, and use high-purity nitrogen with a purity ≥ 99.999% for a refining, refining time 45min, static After standing for 45 minutes, put the molten aluminum into the holding furnace.

S2: Alloy the molten aluminum in the holding furnace, set the temperature at 795°C, add aluminum-iron alloy, aluminum-manganese alloy, aluminum-zinc alloy, aluminum-erbium alloy, aluminum-titanium alloy, aluminum-beryllium alloy, aluminum-vanadium alloy, and use electromagnetic Stir for 30 minutes, then stand still for 40 minutes, take a sample and analyze the composition before the furnace, and feed or dilute according to the result until the composition is qualified, and then enter the refining process.

S3: Carry out secondary refining on the molten aluminum after alloying in the holding furnace, add granular refining agent at 2.8kg/t, and use high-purity nitrogen with a purity ≥ 99.999% for refining. After that, slag removal is carried out, the refining temperature is set at 790°C, and the refining is allowed to stand for 45 minutes.

S4: The aluminum liquid is poured through the holding furnace, and the AlTiC wire is fed online before entering the degassing box. The wire feeding speed is 1.8m/min. Two filter plates, 40 mesh in the front and 60 mesh in the back, are used for double-stage filtration.

S5: Continuously cast the molten aluminum after S4 on-line processing, adopt horizontal casting, and add a 16-mesh casting filter to filter the scale at the gate, control the casting temperature to 713°C, the casting speed to 6.8t/h, and the cooling water temperature 30°C, the billet temperature is 540°C.

S6: Straighten the continuous casting slab, control the rolling temperature at 530°C, and control the finishing rolling temperature at 280°C by controlling the flow and pressure of the emulsion. Specifically, the emulsification flow rate is 38m ³ /h , the pressure is 200kPa.

S7: Water-cool the rolled aluminum rod to 80°C, dry it, and take it up tightly. During the annealing treatment, the temperature is raised to 455° C. within 8 hours, kept at a temperature of 93 hours, and then cooled to room temperature with the furnace. After completion, the aluminum alloy for extrusion of the present invention is obtained.

Example 2

The components of the aluminum alloy for extrusion and the mass percentage of each component are: Si 0.1%, Fe 0.16%, Mn 1.8%, Zn 0.18%, Er 0.06%, Ti 0.015%, Be 0.08%, V 0.02%, the rest Al and unavoidable impurities, the total amount of impurities is not more than 0.015%.

S1: Put the remelted aluminum ingot of Al99.70 into the smelting furnace, heat it to melt, keep it warm at 780°C, add refining agent to the melt, and use high-purity nitrogen with a purity ≥ 99.999% for a refining, refining time 40min, static After standing for 45 minutes, put the molten aluminum into the holding furnace.

S2: Alloy the molten aluminum in the holding furnace, set the temperature at 780°C, add aluminum-iron alloy, aluminum-manganese alloy, aluminum-zinc alloy, aluminum-erbium alloy, aluminum-titanium alloy, aluminum-beryllium alloy, aluminum-vanadium alloy, and use electromagnetic Stir for 35 minutes, then stand still for 45 minutes, take a sample and analyze the ingredients before the furnace, and feed or dilute according to the results until the ingredients are qualified, and then enter the refining process.

S3: Carry out secondary refining on the molten aluminum after alloying in the holding furnace, add granular refining agent at 2kg/t, and use high-purity nitrogen with a purity ≥ 99.999% for refining. Carry out slag removal, set the refining temperature at 785°C, and let stand for 45 minutes after refining.

S4: The aluminum liquid is poured through the holding furnace, and the AlTiC wire is fed online before entering the degassing box. The wire feeding speed is 1.5m/min. Two filter plates, 40 mesh in the front and 60 mesh in the back, are used for double-stage filtration.

S5: Continuously cast the molten aluminum after the online treatment of S4, adopt horizontal casting, and add a 16-mesh casting filter to filter the scale at the gate, control the casting temperature to 710°C, the casting speed to 6.5t/h, and the cooling water temperature 35°C, and the billet temperature is 520°C.

S6: Straighten the continuous casting slab, control the rolling temperature at 510°C, and control the finishing rolling temperature at 200°C by controlling the flow and pressure of the emulsion. Specifically, the emulsification flow rate is 35m ³ /h , the pressure is 180kPa.

S7: Water-cool the rolled aluminum rod to 60°C, dry it, and take it up tightly. During the annealing treatment, the temperature is raised to 460° C. within 9 hours, kept at a temperature of 90 hours, and then cooled to room temperature with the furnace. After completion, the aluminum alloy for extrusion of the present invention is obtained.

Example 3

The components of aluminum alloy for extrusion and the mass percentage of each component are: Si 0.2%, Fe 0.2%, Mn 2%, Zn 0.05%, Er 0.03%, Ti 0.04%, Be 0.04%, V 0.01%, the rest Al and unavoidable impurities, the total amount of impurities is not more than 0.015%.

S1: Put the remelted aluminum ingot of Al99.70 into the smelting furnace, heat it to melt, keep it warm at 800°C, add refining agent to the melt, and use high-purity nitrogen with a purity ≥ 99.999% for a refining, refining time 40min, static After standing for 45 minutes, put the molten aluminum into the holding furnace.

S2: Alloy the molten aluminum in the holding furnace, set the temperature at 800°C, add aluminum-iron alloy, aluminum-manganese alloy, aluminum-zinc alloy, aluminum-erbium alloy, aluminum-titanium alloy, aluminum-beryllium alloy, aluminum-vanadium alloy, and use electromagnetic Stir for 35 minutes, then stand still for 45 minutes, take a sample and analyze the ingredients before the furnace, and feed or dilute according to the results until the ingredients are qualified, and then enter the refining process.

S3: Carry out secondary refining on the molten aluminum after alloying in the holding furnace, add granular refining agent at a rate of 3kg/t, and use high-purity nitrogen with a purity ≥ 99.999% for refining. Carry out slag removal, set the refining temperature to 795°C, and let stand for 45 minutes after refining.

S4: The aluminum liquid is poured through the holding furnace, and the AlTiC wire is fed online before entering the degassing box. The wire feeding speed is 2m/min. A filter plate, which is respectively the 40 mesh filter plate of the front channel and the 60 mesh filter plate of the rear channel, performs double-stage filtration.

S5: Continuously cast the molten aluminum after S4 on-line treatment, adopt horizontal casting, and add a 16-mesh casting filter to filter the scale at the gate, control the casting temperature to 720°C, the casting speed to 7.5t/h, and the cooling water temperature 25°C, and the billet temperature is 550°C.

S6: Straighten the continuous casting slab, control the rolling temperature at 540°C, and control the finishing rolling temperature at 260°C by controlling the flow and pressure of the emulsion. Specifically, the emulsification flow rate is 36m ³ /h , the pressure is 190kPa.

S7: Water-cool the rolled aluminum rod to 70°C, dry it, and take it up tightly. During the annealing treatment, the temperature is raised to 450° C. within 7 hours, kept at a temperature of 96 hours, and then cooled to room temperature with the furnace. After completion, the aluminum alloy for extrusion of the present invention is obtained.

Comparative example 1

No Er was added to the composition of the aluminum alloy for extrusion, and the rest were the same as in Example 1.

Comparative example 2

Si is not added to the composition of the aluminum alloy for extrusion, and the rest is the same as in Example 1.

Comparative example 3

No Be was added to the composition of the aluminum alloy for extrusion, and the rest were the same as in Example 1.

Comparative example 4

No Er, Si, and Be were added to the composition of the aluminum alloy for extrusion, and the rest were the same as in Example 1.

Comparative example 5

Fe is not added to the composition of the aluminum alloy for extrusion, and the rest are the same as in Example 1.

Comparative example 6

No Zn is added to the composition of the aluminum alloy for extrusion, and the rest are the same as in Example 1.

Comparative example 7

No Fe, Zn, and Er were added to the composition of the aluminum alloy for extrusion, and the rest were the same as in Example 1.

Comparative example 8

The temperature during the annealing treatment in S7 was 560° C., and the rest were the same as in Example 1.

Comparative example 9

The time during the annealing treatment in S7 was 85h (a) and 103h (b), and the rest were the same as in Example 1.

The aluminum alloys prepared in Examples 1-3 and Comparative Examples 1-9 were tested according to GB/T 4909.3, and used for the extrusion production of thin-walled harmonica tubes. The test results are shown in the table below.

As shown in the above table, in terms of tensile strength, Example 1 has increased respectively compared with Comparative Examples 1-9: 9.52%, 8.49%, 8.49%, 16.16%, 7.48%, 9.52%, 17.35%, 15%, 15% (a), 12.75% (b); From elongation aspect, embodiment 1 has improved respectively compared with example 1-9: 30.56%, 34.29%, 30.56%, 56.67%, 27.03%, 38.24%, 56.67%, 38.24% %, 42.42% (a), 38.24% (b); from the aspect of product qualified rate, the unqualified rate of embodiment 1 has reduced respectively compared with comparative example 1-9: 82.76%, 79.17%, 81.48%, 84.38%, 79.17% %, 80%, 82.76%, 77.27%, 82.14% (a), 82.76% (b); from the aspect of mold life, embodiment 1 has improved respectively compared with comparative example 1-9: 27.91%, 25%, 22.22%, 197.3%, 26.44%, 23.6%, 214.29%, 35.8%, 61.76% (a), 64.18% (b).

There is a synergistic effect among the components of the aluminum alloy material of the present invention. If the Si element is not added, the phenomenon of extrusion wall breaking will easily occur, but the addition of Si element will easily cause shrinkage porosity. Through the mutual cooperation of Er, Si and Be, the efficient and thorough precipitation of the manganese element is synergistically promoted. , to promote the precipitation of elements dissolved in the matrix, and precipitate in a dispersed form, without forming a second phase of large particles, so that the second phase is fine and evenly distributed, thereby greatly prolonging the service life of the extrusion die; Die life is an example), embodiment 1 has improved 2.4 compared with comparative example 1, and embodiment 1 has improved 2.2 compared with comparative example 2, and embodiment 1 has improved 2 compared with comparative example 3, and embodiment 1 has improved 7.3 compared with comparative example 4 , the difference sum of comparative examples 1-3 and embodiment 1 is 6.4 (7.3 less than the difference value 7.3 of comparative example 4 and embodiment 1), it can be seen that the combined effect of Er, Si and Be improves the sum of the effect of using separately than respectively up 10.61%.

At the same time, in order to enhance the strength and corrosion resistance of the aluminum alloy material, the present invention increases the content of manganese element, forms FeMnAl ₆ phase by adding Zn, Fe, Er, reduces the solid solution of Mn in the aluminum matrix, and improves the ductility of the alloy. At the same time, it cooperates with Zn and Er to further reduce the solid solution of Mn and reduce the segregation phenomenon, refine the coarse phase in the structure, and solve the problem of high segregation and unevenness of Mn element. At the same time, Zn and Er can assist in the elimination of Si element Existing broken wall or shrinkage porosity problem, Zn, Fe, Er can significantly improve the processing performance of aluminum alloy material; From the above table we can know (also taking extrusion die life as an example), embodiment 1 has improved 2.4% compared with comparative example 1 , embodiment 1 has improved 2.3 compared with comparative example 5, and embodiment 1 has improved 2.1 compared with comparative example 6, and embodiment 1 has improved 7.5 compared with comparative example 7, and the difference sum of comparative examples 1,5,6 and embodiment 1 is 6.8 (7.5 less than the difference between Comparative Example 7 and Example 1), it can be seen that the combined effect of Er, Fe and Zn is 10.29% higher than the sum of the effects of separate use. Therefore, there is a synergistic effect among various elements in the present invention, which improves the comprehensive performance of the aluminum alloy material, and each component is indispensable.

The present invention improves the performance of the material by optimizing the production process and heat treatment process: during the production process, refining is carried out in both the smelting furnace and the holding furnace, two-stage filtration is added and casting filter screens are added to filter most of the impurities, and the substrate is purified with Er and other elements; the heat treatment process Among them, the inventors have found through a large number of experiments that the optimal heat treatment condition is to keep warm at 450-460°C for 88-100h, and the grains grow uniformly after annealing, as shown in Figure 1 (A is the aluminum alloy prepared in Example 1, and B is the The aluminum alloy prepared in Example 8, C is the aluminum alloy b prepared in Comparative Example 9, and D is the aluminum alloy prepared in Comparative Example 2), the grain size in A is uniform, while the extruded walls of B-D are uneven, and C is due to the excessive holding time Long, coarse grains, and segregation phenomenon occurs in the preparation process, the material performance is unstable during extrusion, and aluminum sticking and wall breaking appear. The maximum bearing weight of the mold made of aluminum alloy without the heat treatment process of the present invention is only 6.8t.

Apparently, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in various forms can also be made. It is not necessary and impossible to exhaustively list all the implementation manners here. However, the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims

An aluminum alloy for extrusion, characterized in that the components of the aluminum alloy for extrusion and the mass percentages of each component are: Si 0.1-0.2%, Fe 0.15-0.25%, Mn 1.8-2.4%, Zn 0.05-0.18%, Er 0.03-0.06%, Ti 0.008-0.04%, Be 0.04-0.08%, V 0.01-0.02%, the rest are Al and unavoidable impurities, and the total amount of impurities does not exceed 0.015%.
The aluminum alloy for extrusion according to claim 1, characterized in that: the components of the aluminum alloy for extrusion and the mass percentages of each component are: Si 0.18%, Fe 0.23%, Mn 2.23%, Zn 0.14 %, Er 0.05%, Ti 0.02%, Be 0.06%, V 0.015%, the rest are Al and unavoidable impurities, and the total amount of impurities does not exceed 0.015%.
A method for preparing an aluminum alloy for extrusion according to claim 1 or 2, characterized in that it comprises the following steps:

S1: Add aluminum alloy with a purity of not less than 99.7% into a melting furnace to heat and melt, keep it warm at 780-800°C, blow in refining agent, and conduct a refining with nitrogen or argon to obtain the first aluminum liquid;

S2: Add an intermediate alloy to the first molten aluminum in the holding furnace, and stir for 25-35 minutes to obtain the second molten aluminum; wherein, the temperature of the holding furnace is 780-800°C, and the intermediate alloy is one or more species, containing Si, Fe, Mn, Zn, Er, Ti, Be and V;

S3: After the composition of the second aluminum liquid is qualified, the refining agent is blown in, nitrogen or argon is used for secondary refining, and after standing still, the slag is removed to obtain the third aluminum liquid; After adding the refining agent, the furnace is stuffy for 20-30 minutes, and the refining temperature is 780-800°C;

S4: The third aluminum liquid is poured through the holding furnace, fed with AlTiC wire before entering the degassing box, and then degassed and double-stage filtered to obtain the fourth aluminum liquid;

S5: Continuously cast the fourth molten aluminum, and set a casting filter at the gate; wherein, the casting temperature is 710-720°C, the casting speed is 6.5-7.5t/h, and the cooling water temperature is 25-35°C, The billet temperature is 520-550°C;

S6: rolling the slab obtained by continuous casting in S5 to obtain an aluminum rod; wherein, the rolling temperature is 510-540°C, and the finishing rolling temperature is 200-300°C;

S7: Cool down the aluminum rod to 60-80°C, blow it dry and take it up, then raise the temperature to 450-460°C within 7-9 hours, keep it warm for 88-100 hours, and cool it to 20-30°C with the furnace to obtain the obtained aluminum alloy for extrusion.
The preparation method according to claim 3, characterized in that: in step S1, the time for one refining is 35-45min.
The preparation method according to claim 3, characterized in that: in step S1 or S3, the refining agent is added at 2-3 kg/t aluminum liquid.
The preparation method according to claim 3, characterized in that: in step S4, the pore size of the second filtration in the double-stage filtration is 60 mesh.
The preparation method according to claim 3, characterized in that: in step S5, the speed of feeding AlTiC wire is 1.5-2.0m/min.
The preparation method according to claim 3, characterized in that: in step S5, the pore size of the casting filter is 16 mesh.
The preparation method according to claim 3, characterized in that: in step S7, keep warm for 90-96h.
An extruded product prepared by using the aluminum alloy for extrusion according to claim 1.