Aluminum alloy profile for maritime work ship and preparation method of aluminum alloy profile

Abstract

The invention relates to the field of ship aluminum alloy preparation, in particular to an aluminum alloy profile for a maritime work ship and a preparation method of the aluminum alloy profile for the maritime work ship. The content of Fe is 0.01 to 0.5 percent; the content of Cu is 0.01 to 0.1 percent; the content of Mn is 0.01 to 0.05 percent; the content of B is 0.01 to 0.06 percent; the content of Mg is 0.35 to 0.9 percent; the content of Cr is 0.01 to 0.03 percent; the content of Zn is 0.01 to 0.1 percent; the total content of other impurity elements is less than or equal to 0.1%; and the balance of Al. The aluminum alloy profile has excellent mechanical property and conductivity, and meets the application requirements of 6-series alloy in the maritime work ship industry.

Description

Technical Field

[0001] The present invention relates to the field of ship aluminum alloy preparation, and in particular to an aluminum alloy profile for marine engineering ships and a preparation method thereof. Background Art

[0002] The demand for 6 series high-conductivity aluminum alloys in the transportation industry continues to grow due to their excellent electrical conductivity, good processing performance and strong corrosion resistance. Especially in the field of offshore ships, high-conductivity aluminum materials have important applications in two core aspects: power transmission systems and electronic equipment. High-conductivity aluminum profiles can be used for ship conductive devices and cables, such as ship deck conductive rails, cables and other components, effectively improving the ship's electrical conductivity and corrosion resistance, ensuring the safe operation of ships in harsh offshore environments; at the same time, high-conductivity aluminum alloys can be used to manufacture power transmission, electronic heat dissipation and other equipment for offshore platforms, marine equipment and marine pipelines. Excellent electrical conductivity and corrosion resistance can effectively ensure the safety and efficiency of the project. The existing 6 series alloys have a conductivity of about 30% IACS, which is difficult to meet the high conductivity requirements of key components such as conductive devices, conductive rails and cables in the field of offshore ships, and cannot meet the rapid development and technological progress in the field of offshore ships, which puts higher requirements on the electrical conductivity of 6 series aluminum alloys.

[0003] Therefore, there is an urgent need for an aluminum alloy profile for offshore vessels that has both excellent mechanical properties and electrical conductivity. Summary of the invention

[0004] The present invention aims to solve the problem that it is difficult for aluminum alloy profiles for marine engineering ships to have both excellent mechanical properties and electrical conductivity.

[0005] In order to achieve the above-mentioned object, the first aspect of the present invention provides an aluminum alloy profile for marine engineering ships, wherein the components and their weight percentages in the aluminum alloy profile are:

[0006] Si content is 0.3-0.7%;

[0007] Fe content is 0.01-0.5%;

[0008] Cu content is 0.01-0.1%;

[0009] Mn content is 0.01-0.05%;

[0010] B content is 0.01-0.06%;

[0011] Mg content is 0.35-0.9%;

[0012] Cr content is 0.01-0.03%;

[0013] Zn content is 0.01-0.1%;

[0014] The total content of other impurity elements is ≤0.1%;

[0015] The balance is Al.

[0016] A second aspect of the present invention provides a method for preparing the above-mentioned aluminum alloy profile for offshore ships, wherein the preparation method comprises:

[0017] Melting, slagging, degassing and deslagging, filtering, refining, casting, homogenization, peeling, extrusion, quenching, stretching and straightening, aging treatment;

[0018] The homogenization treatment is (400-580)°C×10h. After the homogenization treatment, the cast rod is cooled at a cooling rate of 2-5°C / min. When the temperature drops to 450°C, the cooling rate is 10-20°C / min until it reaches 20-30°C.

[0019] A third aspect of the present invention provides an aluminum alloy profile for marine engineering vessels produced by the above-mentioned preparation method.

[0020] The beneficial effects of the present invention are:

[0021] By controlling the alloy composition and performing a specific homogenization treatment, the aluminum alloy profile for offshore ships provided by the present invention has both excellent mechanical properties and electrical conductivity. Furthermore, the specific extrusion process and aging treatment make the aluminum alloy performance even better. DETAILED DESCRIPTION

[0022] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0023] It is difficult to produce 5 series aluminum alloy profiles with both mechanical properties and electrical conductivity using existing technologies, and it cannot meet the application requirements of 6 series aluminum alloys in the offshore shipbuilding industry.

[0024] In the present invention, the inventors found that by controlling the alloy composition and adjusting the processing technology, the 6 series aluminum alloy can have both excellent mechanical properties and electrical conductivity.

[0025] To achieve this goal, the inventors tried to optimize the composition of each component and the processing technology of the 6 series aluminum alloy. The inventors found that the above purpose can be achieved through specific composition of each component and specific homogenization treatment. Furthermore, specific extrusion process and aging treatment make the performance of the aluminum alloy even better.

[0026] A first aspect of the present invention provides an aluminum alloy profile for marine engineering ships, wherein the components and their weight percentages in the aluminum alloy profile are:

[0027] Si content is 0.3-0.7%;

[0028] Fe content is 0.01-0.5%;

[0029] Cu content is 0.01-0.1%;

[0030] Mn content is 0.01-0.05%;

[0031] B content is 0.01-0.06%;

[0032] Mg content is 0.35-0.9%;

[0033] Cr content is 0.01-0.03%;

[0034] Zn content is 0.01-0.1%;

[0035] The total content of other impurity elements is ≤0.1%;

[0036] The balance is Al.

[0037] In the present invention, the inventors have found that adding a specific content of B to the alloy components in the above-mentioned specific weight ratio can effectively purify impurities in the aluminum liquid, especially Fe compounds, so that they are precipitated at the bottom of the furnace during smelting, thereby achieving the purpose of purifying the aluminum liquid and reducing impurities.

[0038] A second aspect of the present invention provides a method for preparing the above-mentioned aluminum alloy profile for offshore ships, wherein the preparation method comprises:

[0039] Melting, slagging, degassing and deslagging, filtering, refining, casting, homogenization, peeling, extrusion, quenching, stretching and straightening, aging treatment;

[0040] The homogenization treatment is (400-580)°C×10h. After the homogenization treatment, the cast rod is cooled at a cooling rate of 2-5°C / min. When the temperature drops to 450°C, the cooling rate is 10-20°C / min until it reaches 20-30°C.

[0041] In the present invention, the inventors found that, because at high temperature, the dispersed phase begins to gradually diffuse and precipitate from the collective, as the homogenization treatment temperature increases, the dispersed phase begins to precipitate and diffuse from the entire cross section of the cast rod, and the dispersed phase and coarse compounds in the grain boundary begin to diffuse into the crystal. The higher the temperature, the more intense the diffusion process. The above-mentioned specific insulation temperature and insulation time are conducive to the uniform distribution of the dispersed phase (Mg2Si). When the dispersed phase reaches a certain saturation, a cooling method with a cooling rate of 2-5°C / min is adopted, which can make part of the dispersed phase melt back into the aluminum matrix, play a role in enhancing the performance of the aluminum alloy, and at the same time greatly reduce the casting stress of the aluminum alloy cast rod, which plays a role in improving the extrusion effect. When the temperature is lower than 450°C, a cooling method with a cooling rate of 10-20°C / min is adopted to reduce the precipitation of the dispersed phase dissolved in the aluminum matrix, which can effectively reduce the lattice distortion of the solute atoms, achieve the purpose of improving the electrical conductivity, and then improve the electrical conductivity of the aluminum alloy profile.

[0042] According to the present invention, the extrusion conditions include: ingot heating temperature of 400-550°C, mold temperature of 420-520°C, extrusion barrel temperature of 400-470°C, extrusion speed of 1-6m / min, extrusion ratio of 20-60, guide plate thickness of 140-220mm or no guide plate, number of diversion holes ≤4, and mold working zone length of 3-10mm.

[0043] In the present invention, the specific extrusion ratio and die structure are helpful to reduce the grain breakage of the product, reduce the number of grains per unit volume, and lengthen the grains along the extrusion direction so that the effective path bypassing the grains during the conduction process is shortened, thereby improving the conductivity. At the same time, the grains are elongated in the form of long fibers along the extrusion direction, thereby improving the tensile properties of the profile.

[0044] In the present invention, the guide plate is a front aluminum diversion die module of an aluminum profile forming die used in extrusion production, which can promote aluminum profile forming and stabilize the flow of metal aluminum. The thickness of the conventional guide plate is more than 300 mm. The present invention reduces the thickness of the guide plate or does not provide the guide plate, the purpose is to reduce friction, reduce melt deformation, and reduce the degree of grain crushing.

[0045] According to the present invention, the casting conditions include: 1-3 sets of ultrasonic vibration systems are set in the hot top crystallizer, the depth of the radiation rod of the ultrasonic vibration system immersed in the melt is 15-480mm, the frequency of the ultrasonic vibration system is independently 10-30kHz, the casting speed is 150-180mm / min, the casting temperature is 680-720℃, the cooling water flow rate is 80-120L / min, when the casting length is 300-550mm, the ultrasonic vibration system in the hot top crystallizer is removed, and the hot top crystallizer continues to guide the ingot, the average grain size of the ingot is 150-200μm, and the high-magnification grain size is 4-4.5.

[0046] In the present invention, ultrasonic oscillation of the aluminum liquid at the crystallizer during the casting process can effectively improve the grain size of the cast rod crystallization, effectively control the size of the edge, middle and center of the cast rod, so that the grain size is controlled within 150-200μm, and provide an effective grain grade for subsequent product extrusion production, which is helpful to improve the electrical conductivity, thereby improving the electrical conductivity of the aluminum alloy profile.

[0047] According to the present invention, the aging treatment is (200-230)°C×(6-10h)+(150-180)°C×(6-10)h.

[0048] In the present invention, the peak value + low temperature double-stage aging system can effectively improve the electrical conductivity and mechanical properties of the profile. The peak aging is to make the supersaturated solid solution formed after the profile is quenched to form a β phase and separate from the parent phase during the phase transformation process, which can reduce lattice distortion and electron scattering, and help improve the conductivity. The low temperature secondary aging can transform the supersaturated solid solution that has not been completely transformed in the grain boundary and the grain into a β phase. ’ Phase, which helps to improve the mechanical properties of the profile, so that the performance of the profile is further improved.

[0049] According to the present invention, the smelting conditions include: a smelting temperature of 710-760°C, electromagnetic stirring after smelting for 20-30 minutes, 2-4 electromagnetic stirring times, 5-20 minutes of stirring time, and an interval time of 15-25 minutes.

[0050] In the present invention, there is no particular limitation on slag removal, degassing and slag refinement, and the conventional slag removal, degassing and slag refinement process of 6 series aluminum alloy can be used.

[0051] According to some specific embodiments of the present invention, during degassing, the purity of argon is ≥99.999%, the pressure in the degassing box is 0.3-0.5 MPa, and the rotor speed is 450-500 rpm.

[0052] According to some specific embodiments of the present invention, when the slag removal truck removes slag for the first time, the temperature in the furnace is increased by 10-15°C, and after uniform distribution, samples are taken in front of the furnace at a depth of 1 / 2 of the furnace pool, and the sampling temperature is 720-750°C. After the spectral measurement shows that the components are qualified, the samples are transferred to the insulation furnace for static insulation, and the insulation temperature is 720-750°C for 30-60min.

[0053] According to some specific embodiments of the present invention, three-stage ceramic filtration is adopted.

[0054] According to some specific embodiments of the present invention, Al-Ti-B wire with a B content of 1% is added for online refinement.

[0055] According to the present invention, the peeling conditions include: the peeling thickness is 5-15mm.

[0056] According to the present invention, the quenching conditions include: an inlet quenching temperature of 520-540°C and an outlet quenching zone temperature of 20-120°C.

[0057] A third aspect of the present invention provides an aluminum alloy profile for marine engineering vessels produced by the above processing method.

[0058] Test Method

[0059] The test method for aluminum alloy profile composition is in accordance with GB / T3190-2020, and the testing equipment is Japan Shimadzu direct reading spectrometer.

[0060] The mechanical properties test method is in accordance with GB / T6892-2015, the test equipment is Japan Shimadzu universal tensile testing machine, and the Brinell hardness value is the average of 3 points.

[0061] The conductivity test method is in accordance with GB / T12966-2022, the test equipment is a conductivity tester, and the conductivity is a 5-point average.

[0062] The corrosion resistance test method is in accordance with GB / T10125-2021, and the test equipment is a salt spray tester.

[0063] The technical scheme of the present invention is further described in detail below in conjunction with the embodiments. Obviously, the embodiments described herein are only some embodiments of the present invention and are not intended to limit the present invention. Based on the embodiments in the present invention, all other embodiments implemented by ordinary technicians in the field without making creative improvements belong to the protection scope of the present invention.

[0064] Example 1

[0065] A. Smelting: Prepare aluminum alloy raw materials according to the following weight ratio: Si: 0.55%; Fe: 0.1%; Cu: 0.05%; Mn: 0.01%; B: 0.03%; Mg: 0.53%; Cr: 0.01%; Zn: 0.1%; the balance is Al, add the prepared aluminum alloy raw materials into the smelting furnace, the smelting temperature is 750℃, start electromagnetic stirring 30 minutes after the start of smelting, and stir twice, each time for 15 minutes, with an interval of 15 minutes. When the slag removal car is used for the first time to remove slag, the temperature in the furnace is increased by 10℃, and samples are taken in front of the furnace after being uniformly removed, and samples are taken at the 1 / 2 depth of the furnace pool, and the sampling temperature is 740℃. After the spectrum measurement is qualified, the raw materials are transferred to the holding furnace for static insulation, and the insulation temperature is 740℃ for 60 minutes.

[0066] B. Casting: The casting process is degassed online and filtered with three-stage ceramics. Al-Ti-B wire with a content of 1% is added for online refinement. Argon with a purity of ≥99.999% is introduced into the degassing box, the ventilation pressure is 0.3MPa, and the three rotors rotate at a speed of 450r / min to remove hydrogen. The temperature of the aluminum liquid is controlled at 710-730℃. The casting platform uses a crystallizer with a diameter of Φ446mm, and the ultrasonic vibration system on the three groups of crystallizers is turned on. The depth of the radiation rod immersed in the melt is 350mm. The frequency of the ultrasonic vibration system is 30kHz independently, the casting speed is 170mm / min, the cooling water flow rate is 100L / min, and the casting temperature is 710℃. When the casting length is 370mm, the ultrasonic vibration system in the hot top crystallizer is removed, and the hot top crystallizer continues to guide the ingot. The average grain size of the ingot is 150μm, and the high-magnification grain size is 4.5.

[0067] C. Homogenization treatment: After casting, the ingot is homogenized. The homogenization process parameters are set as follows: 550℃×10h, weak wind cooling, cooling rate of 4℃ / min. When the temperature drops to 450℃, strong wind cooling, cooling rate of 17℃ / min, until 24℃;

[0068] D. Ingot peeling: Ingot cooled to 24℃, use Online peeling machine removes the coarse grain layer on the surface and peels to the ingot diameter

[0069] E. Extrusion: casting temperature is 500℃, mold temperature is 480℃, extrusion barrel temperature is 465℃, extrusion speed is 5.5±0.5m / min, extrusion ratio is 40, guide plate thickness is 140mm, number of diversion holes is 3, mold working zone length is 8mm, water quenching is adopted, quenching temperature is 525℃, and quenching zone temperature is 120℃;

[0070] F. Aging: Aging system 230℃×8h+180℃×8h.

[0071] An aluminum alloy profile A1 was obtained.

[0072] Example 2

[0073] A. Smelting: Prepare aluminum alloy raw materials according to the following weight ratio: Si: 0.5%; Fe: 0.1%; Cu: 0.05%; Mn: 0.05%; B: 0.01%; Mg: 0.5%; Cr: 0.03%; Zn: 0.1%; the balance is Al, add the prepared aluminum alloy raw materials into the smelting furnace, the smelting temperature is 750℃, start electromagnetic stirring 30 minutes after the start of smelting, and stir the electromagnetic stirring twice, each time for 15 minutes, with an interval of 15 minutes. When the slag removal car is used for the first time to remove slag, the temperature in the furnace is increased by 10℃, and samples are taken in front of the furnace after being uniformly distributed, and samples are taken at the 1 / 2 depth of the furnace pool, and the sampling temperature is 740℃. After the spectrum measurement is qualified, the raw materials are transferred to the holding furnace for static insulation, and the insulation temperature is 740℃ for 60 minutes.

[0074] B. Casting: The casting process is degassed online and filtered with three-stage ceramics. Al-Ti-B wire with a content of 1% is added for online refinement. Argon with a purity of ≥99.999% is introduced into the degassing box. The ventilation pressure is 0.3MPa and the three rotors rotate at a speed of 450r / min to remove hydrogen. The temperature of the aluminum liquid is controlled at 710-730℃. The casting platform uses a crystallizer with a diameter of Φ446mm. The ultrasonic vibration system on one group of crystallizers is turned on. The depth of the radiation rod immersed in the melt is 350mm. The frequency of the ultrasonic vibration system is 30kHz, the casting speed is 170mm / min, the cooling water flow rate is 100L / min, and the casting temperature is 710℃. When the casting length is 350mm, the ultrasonic vibration system in the hot top crystallizer is removed, and the hot top crystallizer continues to guide the ingot. The average grain size of the ingot is 200μm, and the high-magnification grain size is level 4;

[0075] C. Homogenization treatment: After casting, the ingot is homogenized. The homogenization process parameters are set as follows: 550℃×10h, slow cooling with weak wind, cooling rate of 4℃ / min. When the temperature drops to 450℃, strong wind cooling is performed, cooling rate of 10℃ / min, until 24℃;

[0076] D. Ingot peeling: Ingot cooled to 24℃, use Online peeling machine removes the coarse grain layer on the surface and peels to the ingot diameter

[0077] E. Extrusion: casting temperature is 450℃, mold temperature is 430℃, extrusion barrel temperature is 420℃, extrusion speed is 3.5±0.5m / min, extrusion ratio is 30, guide plate thickness is 220mm, number of diversion holes is 3, mold working zone length is 8mm, water quenching is adopted, inlet quenching temperature is 520℃, outlet quenching zone temperature is 100℃;

[0078] F. Aging: Aging system 230℃×10h+180℃×10h.

[0079] An aluminum alloy profile A2 is obtained.

[0080] Example 3

[0081] An aluminum alloy profile is prepared according to the preparation method of Example 1, except that the aluminum alloy components are Si: 0.3%; Fe: 0.01%; Cu: 0.01%; Mn: 0.01%; B: 0.01%; Mg: 0.35%; Cr: 0.01%; and Zn: 0.01%.

[0082] Aluminum alloy profile A3 is obtained.

[0083] Example 4

[0084] An aluminum alloy profile is prepared according to the preparation method of Example 1, except that the aluminum alloy components are Si: 0.7%; Fe: 0.5%; Cu: 0.1%; Mn: 0.05%; B: 0.06%; Mg: 0.9%; Cr: 0.03%; and Zn: 0.1%.

[0085] Aluminum alloy profile A4 is obtained.

[0086] Example 5

[0087] The aluminum alloy profile was prepared according to the preparation method of Example 1, except that the homogenization process parameters were set as follows: 550°C×10h, weak wind cooling, a cooling rate of 3°C / min, and when the temperature dropped to 450°C, strong wind cooling was performed at a cooling rate of 15°C / min until 24°C.

[0088] Aluminum alloy profile A5 was obtained.

[0089] Example 6

[0090] Aluminum alloy profiles were prepared according to the preparation method of Example 1, except that the casting temperature was 550°C, the extrusion speed was 6m / min, the extrusion ratio was 60, no guide plate was provided, the number of diversion holes was 2, and the length of the mold working zone was 10mm.

[0091] Aluminum alloy profile A6 was obtained.

[0092] Example 7

[0093] Aluminum alloy profiles were prepared according to the preparation method of Example 1, except that the casting temperature was 400°C, the extrusion speed was 1 m / min, the extrusion ratio was 20, no guide plate was provided, the number of diversion holes was 2, and the length of the mold working zone was 3 mm.

[0094] Aluminum alloy profile A7 was obtained.

[0095] Example 8

[0096] The aluminum alloy profile was prepared according to the preparation method of Example 1, except that the aging system was 200°C×6h+150°C×6h.

[0097] Aluminum alloy profile A8 was obtained.

[0098] Example 9

[0099] The aluminum alloy profile was prepared according to the preparation method of Example 1, except that the aging system was 230°C×10h+180°C×10h.

[0100] Aluminum alloy profile A9 was obtained.

[0101] Comparative Example 1

[0102] The aluminum alloy profile was prepared according to the method of Example 1, except that the homogenization process parameters were set to: 550°C×10h, strong wind cooling, and a cooling rate of 15°C / min until 20°C.

[0103] An aluminum alloy profile DA1 was obtained.

[0104] Comparative Example 2

[0105] The aluminum alloy profiles were prepared according to the method of Example 1, except that the casting temperature was 580° C., the extrusion speed was 8 m / min, the extrusion ratio was 80, the guide plate thickness was 300 mm, the number of diversion holes was 6, and the mold working zone length was 15 mm.

[0106] Aluminum alloy profile DA2 was obtained.

[0107] Comparative Example 3

[0108] The aluminum alloy profiles were prepared according to the method of Example 1, except that the ultrasonic vibration systems on the four groups of crystallizers were turned on and the depth of the radiation rods immersed in the melt was 500 mm.

[0109] Aluminum alloy profile DA3 was obtained.

[0110] Comparative Example 4

[0111] The aluminum alloy profile is prepared according to the method of Example 1, except that the aging treatment is 180° C.×12 h+200° C.×12 h.

[0112] Aluminum alloy profile DA4 was obtained.

[0113] Comparative Example 5

[0114] The aluminum alloy profile is prepared according to the method of Example 1, except that Si: 0.8%; Fe: 0.6%; Cu: 0.15%; Mn: 0.1%; B: 0.04%; Mg: 1%; Cr: 0.1%; Zn: 0.15%. (Outside the alloy composition range of this application)

[0115] Aluminum alloy profile DA54 was obtained.

[0116] The performance of A1-A9 and DA1-DA5 is tested as shown in Table 1.

[0117] Table 1

[0118]

[0119]

[0120] By comparing the embodiments with the comparative examples, it can be seen that the aluminum alloy profile provided by the present invention has excellent mechanical properties, corrosion resistance and electrical conductivity. A1 has the best performance, and the tensile yield hardness index remains high, while the corrosion resistance and electrical conductivity are the best.

[0121] The present invention uses specific alloy components and a specific homogenization treatment to make the aluminum alloy profile have excellent mechanical properties, corrosion resistance and electrical conductivity, meeting the application requirements of 6 series alloys in the offshore shipbuilding industry. Furthermore, the extrusion process, casting process and aging treatment are adjusted to make the aluminum alloy performance even better.

[0122] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An aluminum alloy profile for offshore ships, characterized in that: The components and their weight percentages in the aluminum alloy profile are: Si content is 0.3-0.7%; Fe content is 0.01-0.5%; Cu content is 0.01-0.1%; Mn content is 0.01-0.05%; B content is 0.01-0.06%; Mg content is 0.35-0.9%; Cr content is 0.01-0.03%; Zn content is 0.01-0.1%; The total content of other impurity elements is ≤0.1%; The balance is Al.

2. A method for preparing the aluminum alloy profile for offshore ships according to claim 1, characterized in that: The preparation method comprises: Melting, slagging, degassing and deslagging, filtering, refining, casting, homogenization, peeling, extrusion, quenching, stretching and straightening, aging treatment; The homogenization treatment is (400-580)°C×10h. After the homogenization treatment, the cast rod is cooled at a cooling rate of 2-5°C / min. When the temperature drops to 450°C, the cooling rate is 10-20°C / min until it reaches 20-30°C.

3. The preparation method according to claim 2, characterized in that: The extrusion conditions include: ingot heating temperature of 400-550°C, mold temperature of 420-520°C, extrusion barrel temperature of 400-470°C, extrusion speed of 1-6m / min, extrusion ratio of 20-60, guide plate thickness of 140-220mm or no guide plate, number of diversion holes ≤4, and mold working zone length of 3-10mm.

4. The preparation method according to claim 2, characterized in that: The casting conditions include: arranging 1-3 sets of ultrasonic vibration systems in the hot top crystallizer, the depth of the radiation rod of the ultrasonic vibration system immersed in the melt is 15-480mm, the frequency of the ultrasonic vibration system is independently 10-30kHz, the casting speed is 150-180mm / min, the casting temperature is 680-720℃, the cooling water flow rate is 80-120L / min, when the casting length is 300-550mm, the ultrasonic vibration system in the hot top crystallizer is removed, and the hot top crystallizer continues to guide the ingot, the average grain size of the ingot is 150-200μm, and the high-magnification grain size is 4-4.

5.

5. The preparation method according to claim 2, characterized in that: The aging treatment is (200-230)°C×(6-10h)+(150-180)°C×(6-10)h.

6. The preparation method according to claim 2, characterized in that: The smelting conditions include: a smelting temperature of 710-760° C., electromagnetic stirring after smelting for 20-30 minutes, 2-4 electromagnetic stirring times, 5-20 minutes of stirring time, and 15-25 minutes of interval time.

7. The preparation method according to claim 2, characterized in that: The peeling conditions include: the peeling thickness is 5-15mm.

8. The preparation method according to claim 2, characterized in that: The quenching conditions include: the quenching temperature is 520-540°C, and the quenching temperature is 20-120°C.

9. Aluminum alloy profile for offshore vessels made by the preparation method according to any one of claims 2 to 8.

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