Magnesium-containing 3xxx aluminum alloy material with short-time high-temperature strength for thin-wall part as well as preparation method and application of magnesium-containing 3xxx aluminum alloy material

Abstract

The invention relates to the technical field of aluminum alloy component design and heat treatment for high-temperature working conditions, and discloses a magnesium-containing 3xxx aluminum alloy material with short-time high-temperature strength for a thin-walled workpiece and a preparation method and application thereof.The aluminum alloy material comprises, by mass, smaller than or equal to 0.25 wt% of Si, smaller than or equal to 0.6 wt% of Fe, 0.02-0.15 wt% of Cu, 0.8-1.5 wt% of Mn, 0.8-1.5 wt% of Mg, 0.02-0.25 wt% of Zn, smaller than or equal to 0.2 wt% of Ti and inevitable impurities, the single impurity accounts for less than or equal to 0.05%, and the total amount is less than or equal to 0.15%. The alloy material provided by the invention has high room-temperature strength and high-temperature strength, and is suitable for preparing corrosion-resistant and heat-resistant thin-wall parts of automobiles, electronics and the like; the tensile strength of the material at the room temperature reaches 170 MPa, the elongation is larger than 15%, the tensile strength at the temperature of 350 DEG C is larger than 40 MPa, the elongation is larger than 25%, the tensile strength at the temperature of 550 DEG C is larger than 15 MPa, and the elongation is larger than 15%.

Description

Technical Field

[0001] The present invention relates to the field of aluminum alloy composition design and heat treatment technology for high-temperature working conditions, and in particular to a magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength, a preparation method and application thereof. Background Art

[0002] Aluminum alloy materials are widely used due to their excellent properties. Their application in the automotive and 3C electronics fields has played an important role in promoting the development of the aluminum processing industry. 3xxx aluminum alloy is a heat-treated non-strengthened deformable aluminum alloy. Its main alloying elements are Mn, Mg, etc. It has the characteristics of good corrosion resistance and good processing formability. It is an ideal material for making thin plate processing parts such as automobile engine intake manifolds, radiators, exhaust system mufflers, tail pipes, and electronic and electrical radiators. These operating conditions require 3xxx alloys to have good high-temperature strength.

[0003] Commonly used 3xxx alloys include typical alloy grades such as 3003 and 3004. The room temperature tensile strength of the traditional 3003 aluminum alloy O-state material is usually not higher than 150MPa, which is difficult to meet the application of higher strength requirements. The 3004 alloy introduces the addition of Mg element on the basis of the 3003 alloy, which further improves the mechanical strength of the material at room temperature and is a 3xxx material suitable for high-strength working conditions at room temperature. The current research focus on the performance of 3xxx alloys in the prior art is the influence of alloy component element control, deformation process and heat treatment process on the room temperature mechanical properties of the material. For example, reference [1] (Han Chengyi, Dai Yongqiang, Cheng Yuanpeng, et al. Research on the microstructure and properties of Hazelett continuous casting and rolling 3004 alloy [J]. World Nonferrous Metals, 2017, (10): 4-6.) studied the influence of intermediate annealing process on the microstructure and properties of 3004 aluminum alloy strip, and determined a reasonable intermediate annealing process system; reference [2] (Li Yanqin, Jiang Suiqiang, Liu Jianxing, et al. Effect of homogenization annealing on the properties of cast-rolled 3004-H24 aluminum alloy [J]. Gansu Metallurgy, 2021, 43(05): 66-68) studied the influence of homogenization annealing on the properties of cast-rolled 3004 aluminum alloy.

[0004] Although the room temperature mechanical properties of 3004 alloy are better than those of 3003 alloy, its high temperature mechanical properties are poor. For example, the tensile strength of fully annealed 3004 alloy prepared by conventional process is less than 35MPa at 350℃ and less than 15MPa at 550℃. It cannot function stably in high temperature environment. In the prior art, it is difficult for fully annealed 3xxx aluminum alloy to take into account both room temperature strength and high temperature strength at the same time, and it cannot effectively meet the application scenarios with high requirements on comprehensive material performance, such as the preparation of corrosion-resistant and heat-resistant thin-walled parts.

[0005] There are few reports on the high-temperature mechanical properties of 3xxx alloys in the existing literature, and there are relatively few studies on the service behavior of 3xxx alloys at high temperatures. The factors affecting the high-temperature mechanical properties of 3xxx aluminum alloys, especially the high-temperature mechanical properties above 300°C, are still unclear. In order to enable 3xxx alloys to be better used in corrosion-resistant and heat-resistant applications, it is of great significance to develop magnesium-containing 3xxx aluminum alloy sheets for thin-walled parts that have both room temperature and high-temperature high strength and are suitable for efficient hot rolling processes, as well as their preparation methods and applications. Summary of the invention

[0006] The present invention is intended to provide a magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength, and a preparation method and application thereof, so as to solve the problem that it is difficult to achieve both room temperature and high temperature strength of existing 3xxx aluminum alloy plates in the prior art.

[0007] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength, which includes, by mass percentage, Si≤0.25wt%, Fe≤0.6wt%, Cu 0.02-0.15wt%, Mn0.8-1.5wt%, Mg 0.8-1.5wt%, Zn 0.02-0.25wt%, Ti≤0.2wt%, and unavoidable impurities, with a single impurity accounting for ≤0.05%, a total amount ≤0.15%, and the balance being Al.

[0008] Preferably, as an improvement, the mass ratio of copper element to zinc element satisfies 1<Cu / Zn<2.

[0009] Preferably, as an improvement, the tensile strength of the aluminum alloy material is greater than 175 MPa, and the elongation is greater than 15%; the tensile strength at 350°C is greater than 45 MPa, and the elongation is greater than 25%; and the tensile strength at 550°C is greater than 18 MPa, and the elongation is greater than 15%.

[0010] Preferably, as an improvement, the mass percentage of each raw material is Si 0.15-0.25wt%, Fe 0.3-0.5wt%, Cu0.02-0.09wt%, Mn 1.0-1.5wt%, Mg 0.8-1.5wt%, Zn 0.02-0.11wt%, Ti≤0.2wt%, and inevitable impurities, with a single impurity accounting for ≤0.05%, a total amount ≤0.15%, and the balance is Al.

[0011] Preferably, as an improvement, the mass percentage of each raw material is Si 0.15-0.25wt%, Fe 0.3-0.5wt%, Cu0.02-0.09wt%, Mn 1.0-1.5wt%, Mg 0.8-1.5wt%, Zn 0.02-0.11wt%, Ti0.02~0.05wt%, and inevitable impurities, with a single impurity accounting for ≤0.05%, a total amount ≤0.15%, and the balance being Al.

[0012] Preferably, as an improvement, a method for preparing a magnesium-containing 3xxx aluminum alloy material for a thin-walled part having short-term high temperature strength comprises the following steps:

[0013] Step 1: Casting the alloy components into ingots by semi-continuous method or preparing hot-rolled billets by continuous casting and rolling method;

[0014] Step 2, heating and rolling: using a segmented heating and rolling method to roll the ingot or using a high-efficiency heating and rolling method to roll the hot-rolled billet;

[0015] Step 3: After heating and rolling, cold rolling and annealing are performed in sequence to obtain an alloy material.

[0016] Preferably, as an improvement, in step 2, the high-efficiency hot rolling includes a hot rolling preheating stage and a rolling stage, and the processing conditions of the hot rolling preheating stage are heating at 530-550°C for 4-9h; the processing conditions of the rolling stage are rolling on a hot rolling mill after the temperature reaches 460-490°C, and the final rolling temperature is greater than 250°C.

[0017] Preferably, as an improvement, the processing conditions in the hot rolling preheating stage are heating at 530°C for 4 to 9 hours; the processing conditions in the rolling stage are rolling on a hot rolling mill after the temperature reaches 470°C, and the final rolling temperature is greater than 300°C.

[0018] Preferably, as an improvement, a magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength is used in the preparation of automotive, electronic, and aviation corrosion-resistant and heat-resistant thin-walled parts.

[0019] The principles and advantages of this solution are: in actual application, in this technical solution, a reverse analysis is conducted on the reasons why it is difficult to take into account both the room temperature strength and the high temperature strength of magnesium-containing 3xxx aluminum alloy materials in the prior art: as the temperature rises, the strength of most metal materials gradually decreases, because the thermal motion between metal atoms intensifies at high temperatures, the bonding force weakens, and the material is more easily deformed. Grain size is the main factor affecting the high-temperature mechanical properties of materials. Generally, fine-grained materials have higher strength and toughness at room temperature. However, at high temperatures, due to the large grain boundary area and fast atomic diffusion rate, its strength and creep properties may be reduced; while the strength and creep properties of coarse-grained materials at high temperatures are relatively good. Based on this, this technical solution optimizes the high-temperature mechanical properties of the material by controlling the grain size of the material, and optimizes the elemental composition of the material and the rolling process. In terms of element composition, not only the types and proportions of elements are upgraded in a targeted manner, but the inventors also found that the addition ratio of copper and zinc in the elements has a key influence on the composition and precipitation order of the second phase in the matrix. The solubility of Cu in aluminum is less than 0.1%, which is easy to generate a second phase. Zn exists in aluminum in the form of solid solution, which will promote the transformation of Al6(Fe, Mn) to α-Al 12 The transformation of (Fe, Mn)3Si phase and the reasonable control of the compatibility of copper and zinc elements can reasonably control the Cu-containing AlCu2 and s phase (Al2CuMg) and the Mn-containing Al6(Fe, Mn) phase and α-Al 12 (Fe, Mn)3Si phase precipitation process ensures that the pre-existing second phase exists in the form of fine second phase, inhibiting the recrystallization process of the deformed alloy during the subsequent annealing process. In terms of preparation process: This scheme adopts a semi-continuous casting ingot to cancel the homogenization annealing and directly perform segmented hot rolling or adopts a continuous casting and rolling method to directly prepare hot-rolled billets. The efficient hot rolling process can fully improve the supersaturation of Mn and Mg elements in the alloy and increase the critical annealing temperature Tc. The small-sized second phase particles dispersed in the matrix will strongly affect the subsequent recrystallization process, inhibit the movement of dislocations and subgrain boundaries, and hinder the nucleation and growth of recrystallized grains, thereby obtaining coarse pancake-shaped grains, effectively improving the high-temperature mechanical properties of 3xxx alloys, and effectively shortening the traditional 3xxx alloy hot rolling process. Aluminum alloy sheets for thin-walled components with both room temperature and high-temperature mechanical properties are produced under low-cost manufacturing processes.

[0020] In summary, the beneficial effects of this technical solution are:

[0021] 1. The aluminum alloy material obtained by this technical solution can maintain outstanding room temperature and high temperature mechanical properties. The tensile strength of the material at room temperature reaches 170MPa, and the elongation is greater than 15%. The tensile strength at 350℃ is greater than 40MPa, and the elongation is greater than 25%. The tensile strength at 550℃ is greater than 15MPa, and the elongation is greater than 15%.

[0022] 2. The aluminum alloy material of this technical solution is suitable for efficient heating rolling process, which can effectively reduce the process flow before cold rolling of the material, save more than 12 hours of production time, shorten the process flow, and reduce production energy consumption.

[0023] 3. This technical solution systematically studies the microstructure-performance relationship of 3xxx alloys with different compositions and different preparation processes, as well as the microstructure evolution characteristics at high temperatures. It proposes an efficient heating + rolling process window for different precipitation characteristics for 3xxx alloys with different alloy compositions, and clarifies the differences in the preparation process of 3xxx aluminum alloy plates with different compositions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the 350°C high temperature tensile curve of Example 1 of the present invention.

[0025] Figure 2 This is the 550°C high temperature tensile curve of Example 1 of the present invention.

[0026] Figure 3 This is the room temperature tissue morphology of Example 1 of the present invention.

[0027] Figure 4 This is the microstructure of Example 1 of the present invention after a 550°C high temperature tensile test.

[0028] Figure 5 This is the 350°C high temperature tensile curve of Comparative Example 1 of the present invention.

[0029] Figure 6 This is the 550°C high temperature tensile curve of Comparative Example 1 of the present invention.

[0030] Figure 7 This is the room temperature tissue morphology of comparative example 1 of the present invention.

[0031] Figure 8 This is the microstructure of comparative example 1 of the present invention after a 550°C high temperature tensile test. DETAILED DESCRIPTION

[0032] The following is further described in detail through specific implementations, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the technical means used in the following implementations are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; the materials, reagents, etc. used can all be obtained from commercial channels.

[0033] Program Overview:

[0034] A magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength, comprising, by mass percentage, Si≤0.25wt%, Fe≤0.6wt%, Cu 0.02-0.15wt%, Mn 0.8-1.5wt%, Mg 0.8-1.5wt%, Zn0.02-0.25wt%, Ti≤0.2wt%, and unavoidable impurities, with a single impurity accounting for ≤0.05% and a total amount of ≤0.15%, and the balance being Al.

[0035] A method for preparing a magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength comprises the following steps:

[0036] Step 1: Casting the alloy components into ingots by semi-continuous method or preparing hot-rolled billets by continuous casting and rolling method;

[0037] Step 2, heating and rolling: the billet is heated at a differential temperature, the furnace temperature is set to 500-560℃, and after being kept at 380-490℃ for 3-20h, hot rolling is carried out to 4-8mm, the final rolling temperature is greater than 250℃, and then coiled, and the alloy hot-rolled coil is air-cooled to room temperature. The processing conditions of the hot rolling preheating stage are heating at 530-550℃ for 4-9h; the processing conditions of the rolling stage are rolling on the hot rolling mill after the temperature reaches 460-490℃.

[0038] Step 3: cold-roll and curl the 4-8 mm thick alloy hot-rolled coil to obtain a 0.2-3 mm thick alloy cold-rolled sheet (foil). The 0.2-3 mm thick cold-rolled coil is subjected to a complete annealing process at a temperature of 320-400° C. for 2 hours.

[0039] Example 1

[0040] A magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength includes, by mass percentage, Si0.13wt%, Fe0.55wt%, Cu 0.13wt%, Mn 0.92wt%, Mg 1.03wt%, Zn 0.11wt%, Ti0.0003wt%, and unavoidable impurities, with a single impurity accounting for ≤0.05% and a total amount of ≤0.15%, and the balance being Al.

[0041] A method for preparing a magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength comprises the following steps:

[0042] Step 1: prepare alloy ingots according to the composition ratio. The ingots are prepared by industrial semi-continuous casting: the alloy components are melted in aluminum liquid, converted into ingots, refined, left to stand, and cast.

[0043] Step 2: Differential temperature heating, the furnace temperature is set to 500-560℃, and after 12 hours of insulation at 380-490℃, hot rolling is carried out to 4-8mm, the final rolling temperature is greater than 300℃, and then coiling is carried out, and the alloy hot-rolled coil is air-cooled to room temperature. The processing conditions of the hot rolling preheating stage are heating at 530℃ for 9 hours; the processing conditions of the rolling stage are rolling on the hot rolling mill after the temperature reaches 460℃.

[0044] Step 3: cold-roll and curl the 4-8 mm thick alloy hot-rolled coil to obtain a 0.2-3 mm thick alloy cold-rolled sheet (foil). The 0.2-3 mm thick cold-rolled coil is subjected to a complete annealing process at a temperature of 320° C. for 2 hours.

[0045] Example 2

[0046] A magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength comprises, by mass percentage, Si0.20wt%, Fe0.42wt%, Cu 0.10wt%, Mn 1.23wt%, Mg 1.05wt%, Zn 0.08wt%, Ti0.0003wt%, and unavoidable impurities, with a single impurity accounting for ≤0.05% and a total amount of ≤0.15%, and the balance being Al.

[0047] A method for preparing a magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength comprises the following steps:

[0048] Step 1: prepare alloy ingots according to the composition ratio. The ingots are prepared by industrial semi-continuous casting: the alloy components are melted in aluminum liquid, converted into ingots, refined, left to stand, and cast.

[0049] Step 2: Differential temperature heating, the furnace temperature is set to 500-560℃, and after 12 hours of heat preservation at 380-490℃, hot rolling is carried out to 4-8mm, the final rolling temperature is greater than 300℃, and then coiling is carried out, and the alloy hot-rolled coil is air-cooled to room temperature. The processing conditions of the hot rolling preheating stage are heating at 550℃ for 4h; the processing conditions of the rolling stage are rolling on the hot rolling mill after the temperature reaches 490℃.

[0050] Step 3: cold-roll and curl the 4-8 mm thick alloy hot-rolled coil to obtain a 0.2-3 mm thick alloy cold-rolled sheet (foil). The 0.2-3 mm thick cold-rolled coil is subjected to a complete annealing process at a temperature of 400° C. for 2 hours.

[0051] Example 3

[0052] The difference between this embodiment and embodiment 1 is that the composition of the alloy elements is different. The specific element composition and proportion are shown in Table 1.

[0053] Example 4

[0054] The difference between this embodiment and embodiment 1 is that the composition of the alloy elements is different. The specific element composition and proportion are shown in Table 1.

[0055] Example 5

[0056] The difference between this embodiment and embodiment 1 is that the composition of the alloy elements is different. The specific element composition and ratio are detailed in Table 1. In addition, the raw material for the high-efficiency hot rolling process in embodiment 5 is alloy aluminum liquid. The molten metal liquid is cast and rolled into strips, hot rolled to 4 to 8 mm, and the final rolling temperature is greater than 250°C.

[0057] Example 6

[0058] The difference between this embodiment and embodiment 1 is that the composition of the alloy elements is different, and the specific element composition and ratio are detailed in Table 1; in addition, the raw material for the high-efficiency hot rolling process in embodiment 6 is alloy aluminum liquid, the molten metal liquid is cast and rolled into strips, hot rolled to 4 to 8 mm, and the final rolling temperature is greater than 250°C.

[0059] Example 7

[0060] The difference between this embodiment and embodiment 1 is that the composition of the alloy elements is different. The specific element composition and proportion are detailed in Table 1. In addition, in embodiment 7, the thickness of the plate is 3 mm.

[0061] Comparative Example 1

[0062] The difference between this comparative example and Example 1 is that the composition of the alloy elements is different. The specific element composition and proportion are shown in Table 1.

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 1 is that the composition of the alloy elements is different. The specific element composition and ratio are detailed in Table 1. In addition, the homogenization annealing process is adopted in this comparative example, and the temperature is kept at 630°C for 24 hours, followed by slow cooling to room temperature, and then kept at 380-490°C for 12 hours, and then hot rolled to 4-8 mm.

[0065] Comparative Example 3

[0066] The difference between this comparative example and Example 1 is that the composition of the alloy elements is different. The specific element composition and ratio are detailed in Table 1. In addition, the hot rolling preheating treatment process in this comparative example is different, using 600°C insulation for 24 hours, followed by slow cooling to room temperature, followed by slow cooling to room temperature, and then insulation at 380-490°C for 12 hours before hot rolling to 4-8 mm.

[0067] Comparative Example 4

[0068] The difference between this comparative example and Example 1 is that the hot rolling preheating process in this comparative example is different, and the temperature is kept at 550° C. for 24 hours, and then slowly cooled to below 490° C. for hot rolling treatment.

[0069] Comparative Example 5

[0070] The difference between this comparative example and Example 1 is that in this comparative example, Cu / Zn=0.5.

[0071] Comparative Example 6

[0072] The difference between this comparative example and Example 1 is that in this comparative example, Cu / Zn=3.

[0073] Table 1 Aluminum alloy material composition (wt%) and plate thickness

[0074] Group Si Fe Cu Mn Mg Zn Ti Al thickness Example 1 0.13 0.55 0.13 0.92 1.03 0.11 0.0003 margin 0.2mm Example 2 0.20 0.42 0.10 1.23 1.05 0.08 0.0003 margin 0.2mm Example 3 0.20 0.42 0.08 1.23 1.05 0.05 0.0003 margin 0.2mm Example 4 0.20 0.42 0.08 1.23 1.05 0.05 0.03 margin 0.2mm Example 5 0.14 0.52 0.13 0.94 1.01 0.11 0.0003 margin 0.2mm Example 6 0.21 0.44 0.07 1.25 1.15 0.05 0.03 margin 0.2mm Example 7 0.15 0.50 0.13 0.92 1.03 0.11 0.0003 margin 3mm Comparative Example 1 0.13 0.55 0.20 0.92 1.03 0.35 0.0003 margin 0.2mm Comparative Example 2 0.13 0.57 0.13 0.93 1.04 0.11 0.0003 margin 0.2mm Comparative Example 3 0.20 0.41 0.08 1.21 1.03 0.05 0.0003 margin 0.2mm Comparative Example 4 0.13 0.55 0.13 0.92 1.03 0.11 0.0003 margin 0.2mm Comparative Example 5 0.13 0.55 0.05 0.92 1.03 0.10 0.0003 margin 0.2mm Comparative Example 6 0.13 0.55 0.15 0.92 1.03 0.05 0.0003 margin 0.2mm

[0075] Experimental Example 1

[0076] The morphology and organization of the alloy materials prepared in Example 1 and Comparative Example 1 of the present invention and the samples subjected to the 550°C high temperature tensile test were observed. The test method was to first prepare the metallographic samples and then observe them using a metallographic microscope. The metallographic preparation method was as follows: a metallographic sample with a size of 20×10 mm was taken out along the rolling direction using a metallographic cutting machine, the metallographic sample was inlaid, and 180, 400, 600, 800 and 1200# sandpapers were used for polishing step by step, and the sample surface was polished to a scratch-free state using a polishing paste with a size of 0.5 μm. The polished sample was coated with a mixed acid m(H2SO4):m(H3PO4):m(H2O)=38:43:19). The changes in the organization were observed using a ZEISS Stemi 2000-C metallographic microscope.

[0077] The test results are as follows Figure 3-4 as well as Figure 7-8 As shown: It can be seen that the room temperature structure of Example 1 is coarse pancake-shaped grains, and the grain size in the length direction is greater than 100 μm ( Figure 3 ), after the high temperature tensile test, the grain structure of Example 1 further grew, and the grain size of some grains in the length direction was greater than 200 μm ( Figure 4 ); Comparative Example 1 room temperature structure is a conventional fine equiaxed recrystallized grain structure, the average grain size is 32μm ( Figure 7 ), after the high temperature tensile test, the grain structure of Comparative Example 1 also grew, but the overall grain size was still smaller than that of Example 1 before high temperature tensile test, and the average grain size was 56 μm ( Figure 8 ).

[0078] Experimental Example 2 Performance Test

[0079] The room temperature strength and high temperature strength tests were carried out on the alloy materials prepared in each embodiment of the present invention and the comparative example. The test was repeated three times for each group. The test results are shown in Table 2: The embodiment alloys in the present invention are prepared by adopting a high-efficiency heating rolling process and cooperated with a subsequent rolling heat treatment process, and both have good room temperature mechanical properties and high temperature mechanical properties. The embodiment plates all achieve a tensile strength of 170MPa and an elongation of more than 15% at room temperature, a tensile strength of more than 40MPa at 350°C, an elongation of more than 25%, a tensile strength of more than 15MPa at 550°C, and an elongation of more than 15%.

[0080] Specifically: In Examples 1 to 4, as the alloy element ratio is gradually refined, the room temperature and high temperature properties of the material are gradually improved. In particular, the appropriate addition of Cu and Zn elements can be combined with elements such as Mn and Mg, and with the efficient heating and rolling process, fully retain the solid solution in the matrix, ensuring that a dispersed and fine second phase is precipitated in the subsequent precipitation process, inhibiting the subsequent movement of dislocations and sub-grain boundaries, hindering the nucleation and growth of recrystallized grains, thereby ensuring that coarse grains are obtained. Ensure the room temperature and high temperature strength of the embodiment. The pre-sequence raw material of the efficient heating and rolling process used in Examples 5 to 6 is alloy aluminum liquid, and the molten metal liquid is cast and rolled into a strip, hot rolled to 4 to 8 mm, and the final rolling temperature is greater than 250°C. The casting and rolling process has a fast cooling rate, so that the alloy elements are fully dissolved into the matrix. The small-sized second phase particles dispersed in the matrix will strongly affect the subsequent recrystallization process, inhibit the movement of dislocations and sub-grain boundaries, and hinder the nucleation and growth of recrystallized grains, thereby ensuring that coarse grains are obtained. Example 7 is a plate with a thickness of 3 mm. The plate is prepared by a high-efficiency heating rolling process and has high strength at room temperature and high temperature, and can be suitable for plate application scenarios.

[0081] The alloy composition of Comparative Example 1 does not fall within the scope of the present invention, and the room temperature and low temperature mechanical properties of the plate are insufficient. The alloy compositions of Comparative Examples 2 and 3 fall within the scope of the present invention, but the efficient heating and rolling process used in the present invention is not used, resulting in the formation of large-sized second phase particles (>1μm). This type of second phase will not only not significantly hinder the recrystallization process, but will promote recrystallization nucleation, thereby refining its grain structure. The material structure has fine grains. Due to the large grain boundary area and fast atomic diffusion rate, it cannot guarantee good mechanical properties at high temperatures. The alloy composition of Comparative Example 4 falls within the scope of the present invention, but a lower soaking temperature is used for long-term annealing before hot rolling, resulting in the second phase particles melting back during the soaking process and large-sized second phase particles (>1μm) precipitating before cooling to the hot rolling temperature, which promotes recrystallization nucleation and refines the grain structure; Comparative Example 5 Cu / Zn is too small, the Cu element is fully dissolved in the matrix, and the Zn element is excessive, resulting in Al6 (Fe, Mn) phase to α-Al 12The transformation of the (Fe,Mn)3Si phase is obvious, and the Mn-containing phase is fully precipitated and coarsened, resulting in the inability of the fine dispersed second phase to effectively pin the grains. The deformed alloy undergoes recrystallization and grain refinement during annealing, and the high-temperature mechanical properties are insufficient. In comparison example 6, the Cu / Zn ratio is too large and the Cu element is excessively compatible, resulting in the precipitation of Cu-containing AlCu2 and s phase (Al2CuMg) in the matrix, which become nucleation points for the subsequent deformed alloy during annealing, thereby forming a recrystallized fine-grained structure, resulting in insufficient high-temperature mechanical properties.

[0082] Table 2

[0083]

[0084]

[0085] In addition, the high temperature tensile curves at 350°C and 550°C of Example 1 and Comparative Example 1 of the present invention are as follows: Figure 1-2 as well as Figure 5-6 As shown, the high temperature tensile test was carried out in accordance with GB / T 228.2-2015 "Metallic Material Tensile Test Part 2: High Temperature Test Method". The insulation device used a resistance heating furnace. The heating process was carried out quickly in the early stage. When approaching the control temperature, the heating power was gradually reduced until the test temperature was reached. The tensile test was started after 30 minutes of insulation at the test temperature. The results showed that when stretched at 350°C, the tensile strength of Example 1 was 43MPa ( Figure 1 ) is better than 35MPa ( Figure 5 ), when stretched at 550°C, the tensile strength of Example 1 is 18 MPa ( Figure 2 ) is better than the 12MPa ( Figure 6 ).

[0086] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high temperature strength, characterized in that: Calculated by mass percentage, it includes Si≤0.25wt%, Fe≤0.6wt%, Cu 0.02-0.15wt%, Mn 0.8-1.5wt%, Mg 0.8-1.5wt%, Zn 0.02-0.25wt%, Ti≤0.2wt%, and inevitable impurities, with a single impurity accounting for ≤0.05%, a total amount ≤0.15%, and the balance being Al.

2. The magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength according to claim 1, characterized in that: The mass ratio of copper element to zinc element satisfies 1<Cu / Zn<2.

3. The magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high temperature strength according to claim 2, characterized in that: The tensile strength of aluminum alloy materials is greater than 175MPa, and the elongation is greater than 15%; the tensile strength at 350℃ is greater than 45MPa, and the elongation is greater than 25%; the tensile strength at 550℃ is greater than 18MPa, and the elongation is greater than 15%.

4. The magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high temperature strength according to claim 3, characterized in that: The mass percentage of each raw material is Si 0.15-0.25wt%, Fe 0.3-0.5wt%, Cu 0.02-0.09wt%, Mn1.0-1.5wt%, Mg 0.8-1.5wt%, Zn 0.02-0.11wt%, Ti≤0.2wt%, and inevitable impurities, with a single impurity accounting for ≤0.05%, a total amount ≤0.15%, and the balance is Al.

5. The magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength and its preparation method and application according to claim 4, characterized in that: The mass percentage of each raw material is Si 0.15-0.25wt%, Fe 0.3-0.5wt%, Cu0.02-0.09wt%, Mn 1.0-1.5wt%, Mg 0.8-1.5wt%, Zn 0.02-0.11wt%, Ti0.02-0.05wt%, and inevitable impurities, with a single impurity accounting for ≤0.05% and a total amount of ≤0.15%, and the balance is Al.

6. A method for preparing a magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high temperature strength according to any one of claims 1 to 5, characterized in that: The steps include: Step 1: Casting the alloy components into ingots by semi-continuous method or preparing hot-rolled billets by continuous casting and rolling method; Step 2, heating and rolling: using a segmented heating and rolling method to roll the ingot or using a high-efficiency heating and rolling method to roll the hot-rolled billet; Step 3: After heating and rolling, cold rolling and annealing are performed in sequence to obtain an alloy material.

7. The method for preparing a magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high temperature strength according to claim 6, characterized in that: In step 2, the high-efficiency hot rolling includes a hot rolling preheating stage and a rolling stage. The processing conditions of the hot rolling preheating stage are heating at 530-550°C for 4-9h; the processing conditions of the rolling stage are rolling on a hot rolling mill after the temperature reaches 460-490°C, and the final rolling temperature is greater than 250°C.

8. The method for preparing a magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high temperature strength according to claim 7, characterized in that: The processing condition of the hot rolling preheating stage is heating at 530°C for 4 to 9 hours; the processing condition of the rolling stage is rolling on a hot rolling mill after the temperature reaches 470°C, and the final rolling temperature is greater than 300°C.

9. Use of the magnesium-containing 3xxx aluminum alloy material for thin-walled parts with short-term high-temperature strength according to any one of claims 1 to 5 in the preparation of corrosion-resistant and heat-resistant thin-walled parts for automobiles, electronics, and aviation.

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