5-series alloy and preparation method thereof
By combining melt impact semi-continuous casting and multi-stage homogenization treatment with multiple rolling processes in different directions, the problem of biaxial defects in traditional 5-series alloys was solved, and biaxial isotropic alloy materials with excellent properties were prepared.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-14
- Publication Date
- 2026-04-14
AI Technical Summary
Traditional 5-series alloys suffer from problems such as compositional and microstructure segregation, large grain size, and high stress caused by the "three-crystal region" during casting. Furthermore, they exhibit bitropic defects during deformation, which affect the overall performance of the alloy.
A 5-series alloy with equiaxed crystal structure was prepared by using a process of melt impact semi-continuous casting combined with multi-stage heating homogenization treatment and multiple rolling in different directions. Bitropic defects were eliminated by controlling the alloy composition and process parameters.
A biaxially isotropic alloy material with excellent performance was obtained, eliminating the performance difference between the direction parallel and perpendicular to the deformation direction and improving the overall performance of the alloy.
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Figure CN121852779A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of alloy technology, and more specifically, to a 5-series alloy and its preparation method. Background Technology
[0002] 5-series alloys are widely used in automobiles, railways and ships due to their high strength and corrosion resistance. However, with the advancement of science and technology, the demand for high-performance materials in various industries is becoming increasingly urgent. Therefore, the performance of 5083 alloy, the most widely used 5-series alloy, can no longer meet the requirements, and there is an urgent need for a new 5-series alloy with better performance.
[0003] Large-sized ingots produced by traditional semi-continuous casting technology have obvious "three crystal zones", namely fine-grained zone, columnar crystal zone and coarse-grained zone. This results in intrinsic problems such as composition and structure segregation, large grain size and high stress in the ingot, which directly affect the size and alloy type of the ingot, as well as the overall performance of the ingot after deformation and heat treatment.
[0004] Traditional deformation methods mainly involve deformation in one direction, which is closely related to the microstructure of alloy ingots. Deformation along one direction makes it easier to eliminate the "tri-crystal zone" defect, resulting in a more uniform distribution of properties in the alloy material. However, it also results in severe anisotropy, meaning that the properties of the alloy material vary in different directions (parallel to the deformation direction > perpendicular to the deformation direction > material thickness direction). This is mainly related to the differences in the internal microstructure of the material.
[0005] Therefore, it is necessary to develop and prepare a new type of 5-series alloy to eliminate the biaxial defects of the material that are parallel to and perpendicular to the deformation direction, thereby improving the alloy performance. Summary of the Invention
[0006] The purpose of this application is to provide a 5-series alloy and its preparation method, which can eliminate the biaxial defects of the material parallel to and perpendicular to the deformation direction, obtain a biaxially isotropic alloy material, and the alloy has excellent properties.
[0007] In a first aspect, embodiments of this application provide a method for preparing 5-series alloys, which includes the following steps:
[0008] Aluminum alloy raw materials are prepared according to the alloy composition of 5-series alloys. The alloy composition, by mass percentage, includes: Mg: 4.80-9.20%, Zn: 0.45-1.20%, Mn: ≤0.35%, Fe: ≤0.15%, Ti: ≤0.05%, Zr: 0.08-0.12%, Cu: ≤0.10%, Si: ≤0.10%, Sc: ≤0.20%, with the balance being Al.
[0009] The aluminum alloy raw material is cast into aluminum alloy ingots using a melt impact semi-continuous casting method.
[0010] The aluminum alloy ingot is subjected to a multi-stage heating homogenization process.
[0011] The homogenized aluminum alloy ingot is subjected to multiple rolling processes in different directions.
[0012] In the above technical solution, according to a specific alloy composition, an ingot is first formed by melt impact semi-continuous casting, which overcomes the "three-crystal zone" problem of traditional semi-continuous casting; then, a multi-stage heating homogenization treatment is carried out to obtain a highly uniform ingot; then, based on the equiaxed crystal structure characteristics of the liquid impact ingot, a new deformation process of rolling in different directions is carried out to eliminate the biaxial defects of the material parallel to and perpendicular to the deformation direction, thereby obtaining a biaxially isotropic alloy material with excellent alloy properties.
[0013] Regarding the alloy composition, Mg:Mg can improve the material strength (solid solution strengthening), but the precipitation of a large amount of Al3Mg2 phase along the grain boundaries reduces the plate's resistance to intergranular corrosion and exfoliation corrosion.
[0014] Zn: Zn can improve the strength of materials (solid solution strengthening), but its main function is to improve corrosion resistance. Principle: The addition of Zn will react with Mg, which is more easily precipitated at grain boundaries. 32 (Al,Zn) 49 This reduces the amount of Al3Mg2 phase precipitated at grain boundaries; in addition, Mg 32 (Al,Zn) 49 The electrode potential of the phase is closer to that of the matrix (compared to the Al3Mg2 phase), therefore Mg 32 (Al,Zn) 49 The phase is not easily corroded in a corrosive environment, thus greatly improving the corrosion resistance of the material.
[0015] Mn: Mn forms a dispersed Al6Mn phase in Al, increasing the recrystallization temperature. In addition, it can act as a nucleation site for the Al3Mg2 phase, causing a large amount of Al3Mg2 phase to precipitate within the crystals, which is beneficial to improving the corrosion resistance of the material. However, the Mn content should not be too high. Excessive Mn content will form a large-sized brittle phase (Mn-rich phase), which will seriously affect the deformation ability of the alloy (making it prone to cracking during rolling).
[0016] Ti: Ti can refine the as-cast microstructure.
[0017] Zr: Zr can refine the as-cast microstructure (with a smaller effect than Ti), and is mainly used to increase the recrystallization temperature, hinder the recrystallization process, and refine the recrystallized grains.
[0018] Sc: The fine Al3Sc particles formed during alloy solidification can act as heterogeneous nucleation sites, effectively refining the as-cast microstructure. Secondly, the precipitation of dispersed Al3Sc phase in the solid solution can effectively increase the recrystallization temperature. At the same time, Sc can significantly improve the weldability and joint strength of aluminum alloys, and also has good corrosion resistance.
[0019] In one possible implementation, the melt impact semi-continuous casting method includes the following steps:
[0020] The aluminum alloy raw material is melted into liquid aluminum alloy at a melting temperature of 750℃-800℃. After slag removal, Al-5Ti-1B refining agent is added and stirred evenly to obtain aluminum alloy melt.
[0021] The aluminum alloy melt is subjected to heat treatment at a temperature of 700-710℃ and left to stand for 10-20 minutes.
[0022] The heat-insulated aluminum alloy melt is introduced into a nozzle, and pressure is applied to the aluminum alloy melt, causing it to be ejected from the nozzle onto the crystallizer under pressure, thereby obtaining the aluminum alloy ingot.
[0023] In one possible implementation, the temperature of the sprayed aluminum alloy melt is 700-710℃.
[0024] In the above technical solution, the sprayed melt temperature is 700-710℃. If the spraying temperature is too low, the melt fluidity will be reduced and the nozzle will be easily blocked. If the spraying temperature is too high, the melt fluidity will be too large and the melt will easily flow out of the nozzle.
[0025] In one possible implementation, the number of nozzles is 25-30, and the diameter is 3.3-3.9 mm; the nozzles are positioned 20-30 mm above the two-phase region.
[0026] In the above technical solution, the nozzle diameter is 3.3-3.9mm. If the nozzle diameter is too small, nozzle clogging is likely to occur; if the nozzle diameter is too large, the thickness of the liquid phase zone will be increased, resulting in a weak impact effect.
[0027] The nozzle should be placed 20-30mm above the two-phase zone. If the distance is too small, the solid-liquid interface will shift downward, which may cause casting cracks. If the distance is too large, the impact effect will be affected.
[0028] In one possible implementation, the casting speed is 30-35 mm / min and the injection pressure is 10-15 kPa when casting ingots with a thickness of 0-50 mm, and the casting speed is 45-55 mm / min and the injection pressure is 30-45 kPa when casting ingots with a thickness greater than 50 mm.
[0029] In the above technical solution, the casting speed is 30-35mm / min and the injection pressure is 10-15Kpa when the casting thickness is 0-50mm. The main purpose of the low casting speed and low injection pressure at this stage is to obtain a pre-solidified solidified solid of a certain thickness to prevent aluminum liquid leakage during subsequent casting processes.
[0030] When the casting thickness is greater than 50mm, the casting speed is 45-55mm / min and the injection pressure is 30-45Kpa: This stage is the final impact ingot required. The casting speed and injection pressure are increased to obtain a semi-continuous molten impact ingot with uniform and fine structure.
[0031] In one possible implementation, the water flow rate during casting is greater than 400 L / min, and the casting water temperature is 5-40℃.
[0032] In the above technical solution, the casting water flow rate is greater than 400L / min. If the casting water flow rate is too low, solidification will be insufficient and aluminum liquid will easily leak from the side.
[0033] The casting water temperature should be between 5-40℃. If the temperature is too low, the solidification speed will be too fast, resulting in poor impact effect; if the temperature is too high, the solidification will be insufficient, and aluminum liquid will easily leak from the side.
[0034] In one possible implementation, the heating rate during the homogenization process is 38-41 °C / h;
[0035] The homogenization process is a three-stage homogenization process. The first stage of homogenization is to keep the temperature at 400-418℃ for 4-6 hours, the second stage of homogenization is to keep the temperature at 435-440℃ for 2-5 hours, and the third stage of homogenization is to keep the temperature at 455-475℃ for 3-6 hours.
[0036] In the above technical solution, the first-stage homogenization is carried out at 400-418℃ for 4-6 hours: the alloy contains Zr, which has the effect of increasing the recrystallization temperature. Its precipitation temperature is about 400-420℃. At this temperature, a large number of dispersed Al3Zr particles can be obtained, which can increase the recrystallization temperature, which is beneficial to subsequent rolling and improves the material properties.
[0037] Second-stage homogenization: 435-440℃ × 2-5h: Under this alloy composition, Al3Mg2 and Mg are present in the ingot. 32 (Al,Zn) 49 The low-melting-point phase needs to be eliminated by heat treatment to ensure that it does not crack during subsequent rolling. However, the two phases have different melting points. Therefore, the homogenization secondary temperature is set to 435-440℃ and the holding time is 2-5h, while ensuring that neither phase is overheated.
[0038] The third stage of homogenization (455-475℃ × 3-6h): To ensure the production of aluminum alloy rolled plates with uniform composition, the ingot needs to have high homogeneity. Since Mg diffuses slowly, a highly uniform ingot cannot be obtained at a low temperature of 435-440℃. Therefore, the ingot is held at 455-475℃ for a period of time to allow Mg to diffuse extensively, thus obtaining a highly uniform aluminum alloy ingot. However, the time should not be too long (as this increases costs).
[0039] In one possible implementation, the initial rolling temperature during the rolling process is 420-435℃, the temperature is held for 0.5-2 hours, followed by hot deformation with a deformation amount of more than 90%, and the final rolling temperature is greater than 250℃.
[0040] In one possible implementation, the aluminum alloy ingot has mutually perpendicular directions A and B on its surface perpendicular to the thickness direction. The rolling method is as follows: the first pass rolls along direction A with a deformation of 6.7-7.1%; the second pass rolls along direction B with a deformation of 6.7-7.1%; the third pass rolls along direction A with a deformation of 10.8-11.5%; the fourth pass rolls along direction B with a deformation of 10.8-11.5%; the fifth pass rolls along direction A with a deformation of 14.3-14.6%; and the sixth pass... The rolling deformation along direction B is 10.0-20.0%, the seventh pass along direction A is 20.0-21.0%, the eighth pass along direction B is 20.0-21.0%, the ninth pass along direction A is 25.7-26.0%, the tenth pass along direction B is 25.7-26.0%, the eleventh pass along direction A is 19.0-19.2%, and the twelfth pass along direction B is 19.0-19.2%, with a rolling deformation of >89%.
[0041] Secondly, this application provides a 5-series alloy, which is prepared by the 5-series alloy preparation method provided in the first aspect. The microstructure of the 5-series alloy is short fiber structure both parallel to the deformation direction and perpendicular to the deformation direction.
[0042] In the above technical solution, the alloy material has the characteristics of being biaxially isotropic and has excellent alloy performance. Attached Figure Description
[0043] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0044] Figure 1 This is a schematic diagram showing the arrangement of nozzles and conduits used in the casting process according to an embodiment of this application.
[0045] Figure 2 This is a schematic diagram of the structure of the ingot obtained by casting in an embodiment of this application;
[0046] Figure 3 This is a diagram showing the microstructure of the ingot obtained from casting in Example 1;
[0047] Figure 4 The microstructure diagram is shown for the ingot obtained from the casting of Comparative Example 1.
[0048] Figure 5 This is a microstructure diagram of the sheet metal obtained by rolling in Example 1;
[0049] Figure 6 This is a microstructure diagram of the sheet metal obtained by rolling in Comparative Example 1. Detailed Implementation
[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0051] The following is a detailed description of the 5-series alloys and their preparation methods according to embodiments of this application.
[0052] This application provides a method for preparing a 5-series alloy, which includes the following steps:
[0053] (1) Alloy composition: The aluminum alloy raw materials are prepared according to the alloy composition of the 5 series alloys. The alloy composition by mass percentage includes: Mg: 4.80-9.20%, Zn: 0.45-1.20%, Mn: ≤0.35%, Fe: ≤0.15%, Ti: ≤0.05%, Zr: 0.08-0.12%, Cu: ≤0.10%, Si: ≤0.10%, Sc: ≤0.20%, with the balance being Al.
[0054] (2) Ingot preparation: The aluminum alloy raw materials are cast into aluminum alloy ingots by the melt impact semi-continuous casting method.
[0055] In some embodiments of this application, the melt impact semi-continuous casting method includes the following steps:
[0056] S1. Add aluminum alloy raw materials to the melting furnace according to the proportion, mix them evenly, and then melt them into liquid aluminum alloy. The melting temperature is 750℃-800℃. After removing the slag, add Al-5Ti-1B refining agent and stir evenly to obtain aluminum alloy melt.
[0057] S2. Place the high-temperature aluminum alloy melt obtained above in a pressure holding furnace for heat preservation treatment, set the heat preservation temperature to 700-710℃, and let it stand for 10-20 minutes.
[0058] S3. The aluminum alloy melt after being heat-treated in the pressure holding furnace is introduced into the nozzle through a conduit. After the aluminum liquid in the nozzle stabilizes, the nozzle baffle is opened. By applying pressure to the aluminum alloy melt, the aluminum alloy melt is sprayed from the nozzle onto the crystallizer under pressure to obtain aluminum alloy ingots.
[0059] In some embodiments of this application, the temperature of the sprayed aluminum alloy melt is 700-710°C.
[0060] In some embodiments of this application, the number of nozzles is 25-30, with a diameter of 3.3-3.9 mm; the nozzles are positioned 20-30 mm above the two-phase zone; the arrangement is based on the ingot size, with denser nozzles at the edges and sparser nozzles in the center, the purpose being to ensure that the two-phase zone thickness is the same in the edges and center on the same horizontal plane during the casting process. Corresponding to the nozzles, the number of conduits is 25-30, with a diameter of 30-50 mm and a length of 250-300 mm. As one embodiment, the distribution of nozzles and conduits is shown below. Figure 1 (Unit: mm)
[0061] In some embodiments of this application, the casting speed is 30-35 mm / min and the injection pressure is 10-15 kPa when casting ingots with a thickness of 0-50 mm, and the casting speed is 45-55 mm / min and the injection pressure is 30-45 kPa when casting ingots with a thickness greater than 50 mm.
[0062] In some embodiments of this application, the water flow rate during casting is greater than 400 L / min, and the casting water temperature is 5-40℃.
[0063] (3) Homogenization treatment: The aluminum alloy ingot is subjected to multi-stage heating homogenization treatment.
[0064] In some embodiments of this application, the heating rate during homogenization is 38-41°C / h;
[0065] In some embodiments of this application, the homogenization process is a three-stage homogenization process: the first stage of homogenization is to keep the temperature at 400-418℃ for 4-6 hours, the second stage of homogenization is to keep the temperature at 435-440℃ for 2-5 hours, and the third stage of homogenization is to keep the temperature at 455-475℃ for 3-6 hours.
[0066] (4) Rolling process: The homogenized aluminum alloy ingot is milled and then rolled in multiple directions.
[0067] In some embodiments of this application, the initial rolling temperature during the rolling process is 420-435°C, the holding temperature is 0.5-2h, followed by hot deformation with a deformation amount of more than 90%, and the final rolling temperature is greater than 250°C.
[0068] In some embodiments of this application, please refer to Figure 2 The aluminum alloy ingot has mutually perpendicular directions A and B on its surface perpendicular to the thickness direction. The rolling method is as follows: the first pass rolls along direction A with a deformation of 6.7-7.1%; the second pass rolls along direction B with a deformation of 6.7-7.1%; the third pass rolls along direction A with a deformation of 10.8-11.5%; the fourth pass rolls along direction B with a deformation of 10.8-11.5%; the fifth pass rolls along direction A with a deformation of 14.3-14.6%; and the sixth pass rolls along direction B with a deformation of 14.3-14.6%. 10.0-20.0%, the seventh pass is rolled along direction A with a deformation of 20.0-21.0%, the eighth pass is rolled along direction B with a deformation of 20.0-21.0%, the ninth pass is rolled along direction A with a deformation of 25.7-26.0%, the tenth pass is rolled along direction B with a deformation of 25.7-26.0%, the eleventh pass is rolled along direction A with a deformation of 19.0-19.2%, and the twelfth pass is rolled along direction B with a deformation of 19.0-19.2%, with a rolling deformation amount >89%.
[0069] This application also provides a 5-series alloy, which is prepared by the 5-series alloy preparation method of the aforementioned embodiments. The 5-series alloy has a short fiber structure in both the direction parallel to the deformation direction and the direction perpendicular to the deformation direction.
[0070] In the embodiments of this application, long fiber structure refers to continuous or nearly continuous fiber structure, while short fiber structure refers to segmented fiber structure.
[0071] The features and performance of this application will be further described in detail below with reference to the embodiments.
[0072] Example 1
[0073] This embodiment provides an alloy sheet, the specific preparation process of which is as follows:
[0074] (1) Alloy composition: Aluminum alloy raw materials were prepared according to the alloy composition of 5 series alloys. The alloy composition is shown in Table 1:
[0075] Table 1 Alloy Composition
[0076]
[0077] (2) Melting and casting: The aluminum alloy raw materials are cast into aluminum alloy ingots by using the melt impact semi-continuous casting method.
[0078] S1. Add the aluminum alloy raw materials to the melting furnace according to the proportion, mix them evenly, and then melt them into liquid aluminum alloy. The melting temperature is 750℃. After removing the slag, add Al-5Ti-1B refining agent and stir evenly.
[0079] S2. Place the high-temperature aluminum alloy melt obtained above into a pressure holding furnace, set the holding temperature to 710℃, and let it stand for 15 minutes.
[0080] S3. The aluminum alloy melt in the pressure holding furnace is introduced into the nozzle through the conduit. After the aluminum liquid stabilizes, the nozzle baffle is opened. By applying pressure to the melt, the melt is sprayed from the nozzle onto the crystallizer under pressure to obtain an aluminum alloy ingot with a thickness × width of 400mm × 1655mm. The length is cast according to the requirements.
[0081] The specifications are as follows: the sprayed melt temperature is 710℃, there are 27 nozzles with a diameter of 3.5mm, the nozzles are placed 20mm above the two-phase zone, the casting speed is 30mm / min when the casting thickness is 0-50mm, the spraying pressure is 10Kpa, the casting speed is 50mm / min when the casting thickness is greater than 50mm, the spraying pressure is 30Kpa, the casting water flow rate is greater than 500L / min, the casting water temperature is 25℃, there are 27 conduits with a diameter of 30mm and a length of 260mm.
[0082] (3) Homogenization: The above ingots are subjected to three-stage homogenization treatment to obtain ingots with uniform structure. The homogenization process is shown in Table 2.
[0083] Table 2 Homogenization Process
[0084]
[0085] (4) Rolling: The homogenized ingot is milled and placed in a muffle furnace and held at 430°C for 1 hour for rolling. The deformation is controlled at 90% and the final rolling temperature is greater than 250°C.
[0086] The first pass rolls with a deformation of 6.7-7.1% along direction A; the second pass rolls with a deformation of 6.7-7.1% along direction B; the third pass rolls with a deformation of 10.8-11.5% along direction A; the fourth pass rolls with a deformation of 10.8-11.5% along direction B; the fifth pass rolls with a deformation of 14.3-14.6% along direction A; the sixth pass rolls with a deformation of 10.0-20.0% along direction B; the seventh pass rolls with a deformation of 20.0-21.0% along direction A; the eighth pass rolls with a deformation of 20.0-21.0% along direction B; the ninth pass rolls with a deformation of 25.7-26.0% along direction A; the tenth pass rolls with a deformation of 25.7-26.0% along direction B; the eleventh pass rolls with a deformation of 19.0-19.2% along direction A; and the twelfth pass rolls with a deformation of 19.0-19.2% along direction B. Subsequent finishing rolling is then performed on the plate, producing alloy plates with a deformation of 90%.
[0087] Comparative Example 1
[0088] This comparative example provides an alloy sheet whose preparation process differs from that of Example 1 in that:
[0089] (2) Smelting and casting: Traditional semi-continuous casting of ingots is adopted.
[0090] S1. Add the aluminum alloy raw materials to the melting furnace according to the proportion, mix them evenly, and then melt them into liquid aluminum alloy. The melting temperature is 750℃. After removing the slag, add Al-5Ti-1B refining agent and stir evenly.
[0091] S2. Set the holding temperature of the aluminum alloy high-temperature melt obtained above to 710℃ and let it stand for 15 minutes.
[0092] S3. High-temperature melt is injected into the crystallizer through a flow channel to obtain the desired ingot, wherein the casting temperature is 710℃.
[0093] (4) Rolling: Rolling is carried out in one direction using the traditional method.
[0094] After homogenization, the ingot is milled and placed in a muffle furnace for rolling at 430°C for 1 hour, with the deformation controlled at 90% and the final rolling temperature greater than 250°C.
[0095] The rolling direction is along direction A.
[0096] Testing and Experiment
[0097] I. The microstructure of the ingots obtained from the casting of Example 1 and Comparative Example 1 was analyzed. The specific testing standards were in accordance with GB3246.1-2012 Test Methods for Microstructure of Wrought Aluminum and Aluminum Alloy Products Part 1: Test Methods for Microstructure.
[0098] according to Figure 3It can be seen that the ingots cast by melt impact casting have fine equiaxed crystals from the edge to the center, with uniform grain distribution and a size of 60-70 μm; according to Figure 4 It can be seen that the ingots cast using the traditional semi-continuous casting method have coarse grains and uneven distribution.
[0099] 2. The microstructure of the rolled plates obtained in Example 1 and Comparative Example 1 was analyzed. The specific testing standards were in accordance with GB3246.1-2012 Test Methods for Microstructure of Wrought Aluminum and Aluminum Alloy Products Part 1: Test Methods for Microstructure.
[0100] In Example 1, under the rolling scheme used, the grain length / width ratio was: longitudinal section ≈ cross section; according to Figure 5 It can be seen that the transverse and longitudinal microstructures of the boards obtained by the preparation process of this application are not significantly different, both being short fiber structures, and their size and structure are similar.
[0101] In contrast, under the traditional rolling scheme used in Comparative Example 1, the grain length / width ratio is: longitudinal section >> cross section; according to... Figure 6 It can be seen that the boards obtained by traditional processes have long, strip-shaped fiber structures in the longitudinal direction and short, transverse direction.
[0102] III. The performance of the sheet material in Example 1 was analyzed. The testing standard was carried out in accordance with GB / T 228.1-202X Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method. The analysis results are shown in Table 3.
[0103] Table 3 Alloy property results
[0104]
[0105] As shown in the table above, 550MPa grade ultra-high strength 5-series H116 alloy plates were obtained through high alloying, melt impact casting, and rolling deformation processes. The plates exhibit similar biaxial properties, are isotropic, and have excellent alloy performance.
[0106] In summary, the 5-series alloys and their preparation methods of this application can eliminate the biaxial defects of the material parallel to and perpendicular to the deformation direction, obtain biaxially isotropic alloy materials, and have excellent alloy properties.
[0107] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A method for preparing a 5-series alloy, characterized in that, It includes the following steps: Aluminum alloy raw materials are prepared according to the alloy composition of 5-series alloys, wherein the alloy composition, by mass percentage, includes: Mg: 4.80-9.20%, Zn: 0.45-1.20%, Mn: ≤0.35%, Fe: ≤0.15%, Ti: ≤0.05%, Zr: 0.08-0.12%, Cu: ≤0.10%, Si: ≤0.10%, Sc: ≤0.20%, balance Al; The aluminum alloy raw material is cast into aluminum alloy ingots using a melt impact semi-continuous casting method. The aluminum alloy ingot is subjected to a multi-stage heating homogenization process. The homogenized aluminum alloy ingot is subjected to multiple rolling processes in different directions.
2. The method for preparing 5-series alloys according to claim 1, characterized in that, The melt impact semi-continuous casting method includes the following steps: The aluminum alloy raw material is melted into liquid aluminum alloy at a melting temperature of 750℃-800℃. After slag removal, Al-5Ti-1B refining agent is added and stirred evenly to obtain aluminum alloy melt. The aluminum alloy melt is subjected to heat treatment at a temperature of 700-710℃ and left to stand for 10-20 minutes. The heat-insulated aluminum alloy melt is introduced into a nozzle, and pressure is applied to the aluminum alloy melt, causing it to be ejected from the nozzle onto the crystallizer under pressure, thereby obtaining the aluminum alloy ingot.
3. The method for preparing 5-series alloys according to claim 2, characterized in that, The temperature of the sprayed aluminum alloy molten material is 700-710℃.
4. The method for preparing 5-series alloys according to claim 2, characterized in that, The number of nozzles is 25-30, and the diameter is 3.3-3.9 mm; the nozzles are placed 20-30 mm above the two-phase region.
5. The method for preparing 5-series alloys according to claim 2, characterized in that, The casting speed for ingots with a thickness of 0-50mm is 30-35mm / min, and the injection pressure is 10-15Kpa. The casting speed for ingots with a thickness greater than 50mm is 45-55mm / min, and the injection pressure is 30-45Kpa.
6. The method for preparing 5-series alloys according to claim 2, characterized in that, The water flow rate during casting is greater than 400 L / min, and the casting water temperature is 5-40℃.
7. The method for preparing 5-series alloys according to claim 1, characterized in that, The heating rate during the homogenization process is 38-41℃ / h; The homogenization process is a three-stage homogenization process. The first stage of homogenization is to keep the temperature at 400-418℃ for 4-6 hours, the second stage of homogenization is to keep the temperature at 435-440℃ for 2-5 hours, and the third stage of homogenization is to keep the temperature at 455-475℃ for 3-6 hours.
8. The method for preparing 5-series alloys according to claim 1, characterized in that, The initial rolling temperature during the rolling process is 420-435℃, held for 0.5-2 hours, followed by hot deformation with a deformation amount of more than 90%, and the final rolling temperature is greater than 250℃.
9. The method for preparing 5-series alloys according to claim 1, characterized in that, The aluminum alloy ingot has mutually perpendicular directions A and B on its surface in the direction perpendicular to its thickness. The rolling method is as follows: the first pass is rolled along direction A with a deformation of 6.7-7.1%; the second pass is rolled along direction B with a deformation of 6.7-7.1%; the third pass is rolled along direction A with a deformation of 10.8-11.5%; the fourth pass is rolled along direction B with a deformation of 10.8-11.5%; the fifth pass is rolled along direction A with a deformation of 14.3-14.6%; and the sixth pass is rolled along direction B with a deformation of 14.3-14.6%. The deformation is 10.0-20.0%, with the seventh pass rolling along direction A with a deformation of 20.0-21.0%, the eighth pass rolling along direction B with a deformation of 20.0-21.0%, the ninth pass rolling along direction A with a deformation of 25.7-26.0%, the tenth pass rolling along direction B with a deformation of 25.7-26.0%, the eleventh pass rolling along direction A with a deformation of 19.0-19.2%, and the twelfth pass rolling along direction B with a deformation of 19.0-19.2%, and the total rolling deformation is >89%.
10. A 5-series alloy, characterized in that, It is prepared by the method of any one of claims 1 to 9 for the preparation of 5-series alloys, wherein the microstructure of the 5-series alloy is short fiber structure both parallel to the deformation direction and perpendicular to the deformation direction.