An al-mg-zn-er-zr alloy and a method for producing a hot-rolled sheet

Abstract

The application discloses an Al-Mg-Zn-Er-Zr alloy and a preparation method of a hot-rolled plate, and belongs to the field of non-ferrous metals and preparation thereof.The mass percentage content of the aluminum alloy is as follows: Mg 3.0-6.0%, Zn 1.5-4.0%, Mn 0.1-0.8%, Er 0.1-0.5%, Zr 0.1-0.4%, Fe < 0.2, Si < 0.1, and the rest is Al.After a double-stage homogenization treatment is performed on the ingot with the above components, corresponding hot rolling is performed, and then direct aging treatment is performed to obtain an aluminum alloy plate with excellent performance.Compared with an Al-Zn-Mg alloy, the application has better corrosion resistance, simplifies the alloy preparation method, reduces the production cost, makes the alloy have more excellent comprehensive performance, and expands the application range of the alloy.

Description

TECHNICAL FIELD

[0001] The present application relates to an aluminum magnesium alloy plate containing Er and Zr micro-alloying elements and Zn content of 1.5wt.%-4.0wt.% and its preparation, and belongs to the field of non-ferrous metals and its preparation. BACKGROUND

[0002] Al-Mg alloy is widely used in transportation and other fields due to its good corrosion resistance. With the development of industrial modernization, people have higher requirements for the comprehensive performance and economy of aluminum alloy. The supersaturated solid solution of traditional Al-Mg alloy has difficulty in nucleation during the desorption process, and the nucleation core is small, and the size of the precipitated phase is large. At the same time, there is basically no coherent relationship between the second phase and the matrix after desorption and precipitation, so there is no coherent strain zone around the precipitated phase, so it is difficult to obtain effective precipitation strengthening effect. The traditional Al-Mg alloy cannot obtain high mechanical properties through precipitation strengthening. Although the Al-Zn-Mg alloy has high mechanical properties, the high electrode potential of the alloy matrix caused by the large addition of Zn element results in poor corrosion performance. The characteristics of the two alloys limit their application range, and with the development of industry, higher requirements are put forward for the comprehensive performance of the alloy. While ensuring the corrosion performance, the alloy needs to have high strength.

[0003] Chinese patent CN108330419A discloses a hot deformation and stabilization process of Al-Mg-Mn-Er-Zr alloy plate. The obtained hot-rolled plate is stabilized at 240-300 DEG C. The obtained alloy has medium strength, good long-term corrosion resistance and long-term mechanical stability. However, the process is complex and cumbersome, which increases the cost of alloy plate preparation, and the mechanical properties are not ideal. Chinese patent CN104313521A discloses a preparation process of Al-Zn-Mg-Er alloy plate. The obtained hot-rolled plate is subjected to solid solution and double-stage aging treatment. The obtained alloy has high strength. However, the process is complex and the alloy has poor corrosion resistance.

[0004] In the present application, Er and Zr elements are added to increase the recrystallization temperature during the hot deformation of the alloy, and the deformation structure of the alloy is retained. At the same time, the addition of Zn changes the type of precipitated phase, increases the strengthening mode, and significantly improves the corrosion performance of the alloy. By adjusting the hot rolling process, the alloy has discontinuous phase precipitation at the grain boundary during preparation, which ensures the corrosion resistance of the alloy; by directly aging the alloy after hot rolling, the heat treatment process is optimized, the mechanical properties of the alloy are improved, and the process flow is simplified, thereby reducing the production cost. SUMMARY

[0005] The application aims to provide a new Al-Mg-Zn-Er-Zr alloy and a preparation method of hot-rolled plate, which ensures the corrosion resistance of the alloy and improves the strength of the alloy, simplifies the production process and reduces the production cost.

[0006] In order to achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0007] An aluminum alloy, the mass percentage of which is: Mg 3.0-6.0%, Zn 1.5-4.0%, Mn 0.1-0.8%, Er 0.1-0.5%, Zr 0.1-0.4%, Fe <0.2, Si <0.1, and the rest is Al.

[0008] Preferably, the mass percentage of Er in the aluminum alloy is 0.1-0.2%, and the mass percentage of Zr is 0.1-0.2%.

[0009] Preferably, the mass percentage of Zn in the aluminum alloy is 1.5-4.0%.

[0010] The preparation method of the hot-rolled plate comprises the following steps:

[0011] Step (1), two-stage homogenization process: the first stage is 230-330 DEG C for 8-12 hours, and the second stage is 420-470 DEG C for 18-30 hours.

[0012] Step (2), the hot rolling process is as follows: after homogenization, the material is heated to 440-460 DEG C for 1-2 hours, then hot-rolled with a deformation of 60-90%, the rolling speed is 0.1-1 ms, the single-pass deformation is ≤25%, and then air-cooled to room temperature; then directly aged, the aging process is 120-170 DEG C for 18-30 hours. -1 Compared with the prior art, the application has the following beneficial effects:

[0013] 1. Under the condition of high Mg content, the alloy does not need to be subjected to solid solution treatment process, thereby simplifying the process flow and reducing the production cost.

[0014] 2. By adding Zn, the application reduces the continuous precipitation trend of grain boundary precipitates, ensures the long-term corrosion resistance of the alloy and improves the strength of the alloy.

[0015] 3. By adding Er and Zr, the application changes the composition of the precipitates of the traditional Al-Mg alloy, improves the recrystallization temperature of the alloy and improves the strength of the alloy.

[0016] 4. The application simplifies the production process and reduces the production cost. DETAILED DESCRIPTION

[0017] The application will be further described in connection with the following examples, but the application is not limited to the following examples.

[0018] Example 1

[0019] Four kinds of alloys were prepared, and the chemical compositions of the alloys are shown in Table 1. Alloys 1 and 2 are reference alloys, and alloys 3 and 4 are the alloy compositions of the present application.

[0020] Table 1 Alloy composition table

[0021]

[0022]

[0023] The ingots of the above four kinds of alloys were heated from room temperature to 280°C at a heating rate of 50°C per hour, and then kept at 280°C for 10 hours, and then heated to 450°C, and kept at 450°C for 24 hours, and then cooled to room temperature in the furnace. The alloys were heated to 440°C and kept at 440°C for 2 hours, and then hot-rolled, and the total deformation of the hot-rolling was 80%, and the rolling speed was 0.5 ms -1 , and the single pass deformation was ≤25%. The hot-rolled alloys were directly put into a holding furnace at 140°C for 24 hours. The mechanical properties of the alloy sheets were measured and are shown in Table 2.

[0024] Table 2 Alloy mechanical properties

[0025] Alloy σ0.2(MPa) σUTS(MPa) A(％) Alloy 1 245 409 24.2 Alloy 3 505 568 12 Alloy 3 428 491 10.5 Alloy 4 426 485 10

[0026] Example 2

[0027] The ingots of the above four kinds of alloys were heated from room temperature to 300°C at a heating rate of 50°C per hour, and then kept at 300°C for 8 hours, and then heated to 460°C, and kept at 460°C for 20 hours, and then cooled to room temperature in the furnace. The alloys were heated to 460°C and kept at 460°C for 2 hours, and then hot-rolled, and the total deformation of the hot-rolling was 85%, and the rolling speed was 0.1 ms -1 . The hot-rolled alloys were directly put into a holding furnace at 160°C for 20 hours. The intergranular corrosion properties of the alloys after sensitization were measured according to the ASTM G67 standard. The measured corrosion resistance properties are shown in Table 3:

[0028] Table 3 Intergranular corrosion properties

[0029] Alloy NAMLT(mg / cm2) Alloy 1 4.0 Alloy 2 25.2 Alloy 3 5.2 Alloy 4 5.6 .

Claims

1. An Al-Mg-Zn-Er-Zr alloy, characterized in that, The alloy's mass percentage content is: Mg 5.08–5.11%, Zn 2.89–2.91%, Mn 0.15–0.21%, Er 0.14–0.15%, Zr 0.11–0.15%, Fe < 0.2%, Si < 0.1%, with the remainder being Al; The alloy composition ingot is subjected to a two-stage homogenization treatment, followed by hot rolling; specifically, the following steps are included: Step (1), two-stage homogenization process: the first stage is to keep at 230℃~330℃ for 8~12 hours, and the second stage is to keep at 420℃~470℃ for 18~30 hours; Step (2), the hot rolling process is as follows: after homogenization, the material is heated to 440-460℃ and held for 1-2 hours, then hot rolled with a deformation of 60-90% at a rolling speed of 0.1-1 ms. -1 The deformation amount per pass is ≤25%, then air-cooled to room temperature; then directly aged, the aging process is carried out at 120~170℃ for 18~30 hours.

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