An aluminum alloy thick plate and its preparation process

Abstract

The present invention relates to the technical field of thick aluminum alloy plates, and specifically to a high-performance thick aluminum alloy plate and its preparation process, which includes successively melting, casting, soaking, turning, flaw detection, sawing, forging, trimming and grinding, hot rolling, heat treatment, finishing and surface prestress treatment, aging, straightening and shearing, and secondary flaw detection of aluminum alloy raw materials to obtain a thick aluminum alloy plate. The present invention obtains a thick aluminum alloy plate by successively carrying out deep-well casting, soaking, forging, rolling, and heat treatment on alloy raw materials, making the alloy components diffuse evenly through the process, ensuring full anisotropic deformation during rolling after forging, and making the mechanical properties and metallographic structures of each part uniform after heat treatment. The mechanical properties of each part of the produced thick aluminum alloy plate meet or even exceed the performance requirements of high-performance aluminum alloys for individual forged parts. It can be used in the semiconductor and aerospace fields, is suitable for processing various high-performance large aluminum alloy plate-shaped parts and batch part production, has a wide range of applications, and has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of thick aluminum alloy plates, and specifically to a high-performance thick aluminum alloy plate and a preparation process thereof. Background Art

[0002] As a high-quality aluminum alloy product, 6061 aluminum alloy has good formability, weldability, and machinability, has medium strength, and has good adaptability in many fields. The existing 6061 hot-rolled thick aluminum alloy plate has small rolling deformation, large differences in internal and external structures, many secondary impurity phases, uneven and insufficient deformation in each part, poor mechanical properties and metallographic structures in the core part, and large differences in mechanical properties in the transverse and longitudinal directions. After heat treatment, the strength is low and the difference is large, which has an adverse impact on subsequent processing and use. Therefore, we propose a high-performance thick aluminum alloy plate and a preparation process thereof. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-performance thick aluminum alloy plate and a preparation process thereof to solve the problems raised in the above background art.

[0004] To solve the above technical problems, the present invention provides the following technical solution: A preparation process of a high-performance thick aluminum alloy plate is obtained by the following steps:

[0005] The aluminum alloy raw materials are successively subjected to melting, casting, soaking, turning, flaw detection, sawing, forging, trimming and grinding, hot rolling, heat treatment, finishing and surface prestress treatment, aging, straightening and shearing, and secondary flaw detection to obtain the thick aluminum alloy plate.

[0006] Further, in the melting and casting processes, the aluminum liquid is stirred and slagged multiple times, and after being filtered through a tubular filter, it is cast to prepare a large-sized casting rod with a diameter of 660-950 mm and a length of 6800-7300 mm.

[0007] Further, in the melting process, the process conditions are: melting temperature 720-760 °C, melting time 6-8 h; refining temperature 720-750 °C, refining time 5-6 h; alloying elements are added during the refining process to adjust the chemical composition, and at the same time, chlorine gas and argon gas are introduced to remove hydrogen elements in the aluminum alloy melt, and the gas injection time is 30-60 min.

[0008] Skim the slag before pouring, and at the same time add a grain refiner AlTi5B (wire rod), and use a 40ppi ceramic filter plate to perform tubular filtration on the aluminum alloy melt.

[0009] Furthermore, in the soaking process, the process conditions are as follows: heat up to 510 - 520 °C and hold for 2 hours; then continue to heat up to 555 - 565 °C and hold for 16 - 20 hours to promote the full melting and diffusion of the unbalanced alloy phases in the aluminum alloy; then rapidly cool using strong air and water mist to prevent the precipitation phase from aggregating and growing.

[0010] Furthermore, in the peeling process, the defective layer on the outer surface of the aluminum rod is removed, which is more conducive to the forging and rolling of subsequent processes. After peeling, the obtained finished large-sized cast rod has a diameter of 610 - 920 mm.

[0011] Furthermore, in the flaw detection process, ultrasonic flaw detection is used to detect the defects in the finished large-sized cast rod during the casting and soaking processes.

[0012] Furthermore, in the sawing process, the finished large-sized cast rod is sawed according to the size and length of the final finished sheet material to obtain a bar stock with appropriate dimensions, and the length of the bar stock is 2000 - 3000 mm.

[0013] Furthermore, in the forging process, the process conditions are as follows: the initial forging temperature is 480 - 520 °C, and the final forging temperature is 400 - 450 °C; after upsetting and drawing forging, trimming and grinding are carried out after forging to obtain an aluminum alloy square bar, and the length of the aluminum alloy square bar is 2500 - 4000 mm.

[0014] Furthermore, in the forging process, the process conditions are as follows: the forging temperature is 480 - 520 °C, and the final forging temperature is 370 - 410 °C; the upsetting and drawing forging ratio is 1.46 - 3.62, and the deformation amount per time is 46% - 72%.

[0015] Furthermore, in the hot rolling process, the total deformation amount in the hot rolling shaping stage is 25 - 60%; after hot rolling, an aluminum alloy thick plate is obtained, and the thickness of the aluminum alloy thick plate is 200 - 500 (±0.5) mm, and the length reaches 3 - 8 m.

[0016] Furthermore, in the hot rolling process, the process conditions are as follows: the hot rolling temperature is 480 - 510 °C, and the final rolling temperature is 320 - 350 °C; the total deformation amount in the hot rolling shaping stage is 25 - 60%. A lower final rolling temperature can cause recrystallization on the surface of the aluminum alloy thick plate and prevent the surface grains from becoming coarser.

[0017] In processes such as forging and hot rolling, control the deformation amount of the process to make the deformation of the grains in the aluminum alloy more intense and uniform, increase the recrystallization nuclei, and make the grains of the aluminum alloy after recrystallization finer.

[0018] Furthermore, in the heat treatment process, solution heat treatment is adopted, and the process conditions are: soaking temperature 515 - 520 °C, soaking time 10 - 16 h; then quenching treatment is carried out, and the quenching water temperature is 5 - 35 °C. Due to the large thickness of the thick aluminum alloy plate, during the process of waiting for the core layer to heat up, the grains on the surface of the thick aluminum alloy plate will recrystallize and gradually grow. An overly long heat treatment time will cause the surface grains to be coarse. Therefore, a lower solution temperature and a shorter soaking time help to slow down recrystallization and avoid the growth of aluminum alloy grains.

[0019] Furthermore, finish machining and surface prestressing treatment are carried out after heat treatment. By means of a small amount of cold deformation and finish machining on the surface, the surface prestress is increased, and the surface hardness, strength and surface quality are improved.

[0020] Furthermore, in the aging process, the process conditions are: aging temperature 175 - 180 °C, aging time 8 h.

[0021] Furthermore, the thick aluminum alloy plate comprises the following components by mass percentage: silicon Si: 0.50 - 0.80%; iron Fe: <0.15%; copper Cu: 0.15 - 0.40%; manganese Mn: 0.10 - 0.15%; magnesium Mg: 0.80 - 1.20%; chromium Cr: 0.25 - 0.35%; zinc Zn: <0.25%; titanium Ti: 0.02 - 0.1%; the balance is aluminum Al.

[0022] Furthermore, in the composition of the thick aluminum alloy plate: manganese Mn: 0.12 - 0.15%; chromium Cr: 0.30 - 0.35%.

[0023] In the aluminum alloy raw materials, the aluminum element is selected as pure aluminum ingot with a purity of 99.996%, sourced from Shanghai Xincheng Aluminum Industry Co., Ltd.;

[0024] The silicon element is selected as massive industrial pure silicon with a purity of 99.4%, sourced from Zhengzhou Chunjie Industrial Silicon Co., Ltd.;

[0025] The copper element is selected as massive industrial pure copper with a purity of 99.92%, sourced from Tieling Fuxing Copper Industry Co., Ltd.;

[0026] The magnesium element is selected as massive industrial pure magnesium with a purity of 99.96%, sourced from Luoyang Maige Magnesium Industry Co., Ltd.;

[0027] The manganese and chromium elements are respectively provided by powdered aluminum-manganese alloy AlMn 75 and massive aluminum-titanium alloy AlTi6, sourced from Beijing Gaoke New Materials Technology Co., Ltd.;

[0028] AlTi5B is in wire form, sourced from Liaoning Xinpeng Gaoke Metals Co., Ltd.

[0029] In the above technical solution, during smelting, appropriately increasing the content of alloying element Mn and controlling and reducing the Fe content can reduce the generation of refractory aluminum-iron-silicon secondary phases in aluminum alloy and reduce the damage of residual secondary phases to the precision oxide layer. At the same time, appropriately increasing the content of Cr element can improve the strength of the fabricated thick aluminum alloy plate and improve its comprehensive performance.

[0030] Titanium element can cooperate with chromium to reduce the columnar crystal structure in large cast rods, improve their forging performance, and refine the grains. Manganese and chromium elements can form dispersion phases such as MnAl6, Al7Cr, and (Fe,Mn)Al6, which play a pinning role, hinder the slip of dislocations and the migration of grain boundaries in aluminum alloy, increase the recrystallization temperature, and can play a role in refining grains during the recrystallization process (hot rolling, solution treatment), thereby improving the strength of the fabricated thick aluminum alloy plate. At the same time, chromium can inhibit the precipitation of the magnesium-silicon phase at grain boundaries, which helps to improve the strength of the fabricated thick aluminum alloy plate. However, the manganese element in aluminum alloy will cause severe intragranular segregation in the α phase, affecting the recrystallization process of aluminum alloy, resulting in grain coarsening of aluminum alloy. The homogenization process can eliminate the manganese segregation in aluminum alloy and obtain fine-grained materials.

[0031] The content of silicon element in the system is greater than that of iron element, making the formed aluminum-iron-silicon alloy phase be the β phase, which has better high-temperature stability compared with the α phase, can increase the recrystallization temperature of aluminum alloy, inhibit the diffusion of atoms and the migration of grain boundaries, and prevent the grains from growing and coarsening during hot rolling and solution treatment, which affects the mechanical properties of the final product, the thick aluminum alloy plate.

[0032] Furthermore, the high-performance thick aluminum alloy plate also undergoes electrolytic polishing, surface oxidation, and sol sealing treatment.

[0033] Furthermore, the electrolytic polishing process is specifically as follows:

[0034] Using the high-performance thick aluminum alloy plate as the anode and 304 stainless steel or graphite as the cathode, placing them in an electrolytic polishing solution at a temperature of 72 - 78°C, under a voltage condition of 10 - 15V, electrolytically polish for 25 - 35 min; then under a voltage condition of 0.5 - 0.7V, electrolytically polish for 5 - 30 min; wash with water and dry with nitrogen.

[0035] Furthermore, the electrolytic polishing solution contains 12 - 18 wt% sodium carbonate and 4.5 - 5.5 wt% sodium phosphate, and the pH is 12.5 - 13.5.

[0036] In the above technical solution, by controlling the dissolution of the metal, an electrolytic polishing process is adopted to reduce the surface roughness of the thick aluminum alloy plate. Before electrolytic polishing, the aluminum alloy is subjected to processes such as soaking, heat treatment, surface prestressing treatment, aging, etc., which can promote the formation of a good crystal structure. During the first electrolysis, a relatively high voltage is used to dissolve the oxide film on the surface of the thick aluminum alloy plate, and at the same time, the second phase in the aluminum oxide film layer on the aluminum alloy surface is removed along with the dissolution of the aluminum oxide, thereby obtaining an aluminum alloy surface with a lower roughness. During the second electrolysis, a relatively low voltage is used to promote the dissolution of aluminum elements on the surface of the thick aluminum alloy plate, further improving its surface smoothness.

[0037] Further, mechanical polishing is carried out before electrochemical polishing. The specific process is as follows: sand the aluminum alloy plate with 240 - 2000 - mesh sandpaper for 15 - 60 s; wash and dry.

[0038] Further, the surface oxidation process is specifically as follows:

[0039] Place the thick aluminum alloy plate obtained after electrolytic polishing in an oxidation electrolyte at 23 - 27 °C, and carry out micro - arc oxidation treatment for 25 - 35 min under the conditions of a positive voltage of 500 V, a negative voltage of 50 V, a duty cycle of 40 - 50%, and a frequency of 800 - 1000 Hz; wash with water and dry with nitrogen to form a micro - arc oxidation film.

[0040] Further, the oxidation electrolyte contains 8 - 10 g / L sodium silicate and 2 - 10 g / L sodium phosphate, and the pH is adjusted to 12.5 - 13.5 with sodium hydroxide.

[0041] In the above technical solution, during the micro - arc oxidation process, the discharge causes the aluminum elements on the surface of the aluminum alloy to melt, react with the oxidation electrolyte, and quickly cool and solidify, thereby forming oxides. The silicate ions in sodium silicate participate in the formation of the oxide film layer to form silicon oxide, so that the prepared micro - arc oxidation film is mainly composed of α - phase, γ - phase aluminum oxide and mullite, and has high hardness, wear resistance, and excellent anti - impact spalling performance and mechanical properties.

[0042] Further, secondary electrolytic polishing is carried out after surface oxidation. The specific process is as follows:

[0043] Place the thick aluminum alloy plate obtained after surface oxidation in water at 70 - 80 °C for aging for 100 - 180 min. As the anode, 304 stainless steel or graphite is used as the cathode, and it is placed in a secondary electrolytic polishing solution at 72 - 78 °C. Under the voltage condition of 0.8 - 1.5 V, carry out electrolytic polishing for 25 - 30 min; wash with water and dry with nitrogen to form an oxide film.

[0044] Further, the secondary electrolytic polishing solution contains 12 - 18 wt% sodium carbonate and 4.5 - 5.5 wt% sodium phosphate, and the pH is 9.0 - 13.0.

[0045] In the above technical solution, before the secondary electrolytic polishing process, first, the micro-arc oxidation film in the thick aluminum alloy plate obtained after surface oxidation is hydrated to dissolve the γ-phase alumina on its surface first, and then hydrated alumina is precipitated. Then, the oxidized film obtained after hydration is subjected to secondary electrolytic polishing to remove the hydrated film, thereby removing the γ-phase alumina with relatively poor performance in the outer layer of the micro-arc oxidation film, exposing the α-phase alumina in the inner layer, and further improving the hardness, wear resistance, impact spalling resistance, mechanical properties and other properties of the produced oxidized film.

[0046] Further, the sol sealing is specifically as follows:

[0047] On the surface of the thick aluminum alloy plate obtained after secondary electrolytic polishing, a sol is spin-coated, dried at room temperature for 24 h, slowly heated to 100 - 120 °C, held for 100 - 160 min, and then cooled to room temperature.

[0048] Further, the spin-coating speed is 800 - 1000 r / min, and the heating rate is 0.2 - 0.5 °C / min.

[0049] Further, the sol is one or a mixture of two of a silicon solvent and an aluminum sol.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] The preparation process of the high-performance thick aluminum alloy plate of the present invention obtains a thick aluminum alloy plate by successively carrying out deep-well casting, soaking, forging, rolling, and heat treatment on alloy raw materials. The pre-forging casting rod is fully homogenized, the alloy components are uniformly diffused, the post-forging rolling deformation is sufficient in all directions, and the mechanical properties and metallographic structures of each part are uniform after heat treatment. The mechanical properties of each part of the produced thick aluminum alloy plate reach or even exceed the performance requirements of high-performance aluminum alloys for single forging parts, and can be used in the semiconductor and aerospace fields, and are suitable for processing various high-performance large aluminum alloy plate-shaped parts and batch part production, with a wide range of applications and broad application prospects. Its comprehensive properties such as tissue uniformity, flatness, and surface finish are superior to those of the overall forging, the surface accuracy is within 0.5 mm, there are few secondary impurity phases, and the purity of the aluminum alloy is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0053] Figure 1 is a 100x metallographic structure diagram of the uncorroded thick aluminum alloy plate obtained in Embodiment 1 of the present invention:

[0054] Figure 2It is the 200x metallographic structure diagram after corrosion of the aluminum alloy thick plate obtained in Example 1 of the present invention;

[0055] Figure 3 It is the 100x metallographic structure diagram of the uncorroded aluminum alloy thick plate in Comparative Example 1 of the present invention;

[0056] Figure 4 It is the 200x metallographic structure diagram after corrosion of the aluminum alloy thick plate in Comparative Example 1 of the present invention. Specific embodiments

[0057] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0058] In the aluminum alloy raw materials, aluminum element is selected as pure aluminum ingot with a purity of 99.996%, sourced from Shanghai Xincheng Aluminum Industry Co., Ltd.;

[0059] Silicon element is selected as massive industrial pure silicon with a purity of 99.4%, sourced from Zhengzhou Chunjie Industrial Silicon Co., Ltd.;

[0060] Copper element is selected as massive industrial pure copper with a purity of 99.92%, sourced from Tieling Fuxing Copper Industry Co., Ltd.;

[0061] Magnesium element is selected as massive industrial pure magnesium with a purity of 99.96%, sourced from Luoyang Maige Magnesium Industry Co., Ltd.;

[0062] Manganese and chromium elements are respectively provided by powdered aluminum manganese alloy AlMn 75 , massive aluminum titanium alloy AlTi6, sourced from Beijing Gaoke New Materials Technology Co., Ltd.;

[0063] AlTi5B is a wire, sourced from Liaoning Xinpeng Gaoke Metals Co., Ltd.;

[0064] Silicon solvent: JN-30, sourced from Dongying Yiming New Materials Co., Ltd.

[0065] Example 1: A preparation process for a high-performance aluminum alloy thick plate, including the following preparation processes:

[0066] (1) Manufacturing:

[0067] The aluminum alloy raw materials are successively subjected to melting, casting, soaking, skin turning, flaw detection, sawing, forging, trimming and grinding, hot rolling, heat treatment, finishing and surface prestressing treatment, aging, straightening and shearing, and secondary flaw detection to obtain the aluminum alloy thick plate;

[0068] The smelting process conditions are as follows: smelting temperature is 720 °C, smelting time is 6 h; refining temperature is 720 °C, refining time is 5 h; alloying elements are added during the refining process to adjust the chemical composition, and at the same time, chlorine gas and argon gas are introduced to remove hydrogen elements in the aluminum alloy melt, with the gas injection time being 30 min; slag is skimmed before casting, and at the same time, a grain refiner AlTi5B (wire) is added, and a 40 ppi ceramic filter plate is used to conduct tubular filtration on the aluminum alloy melt to prepare a large-sized casting rod with a diameter of 800 mm and a length of 7000 mm;

[0069] The soaking process conditions are as follows: heating up to 510 °C and holding for 2 h; continuing to heat up to 555 °C and holding for 16 h, and then rapid cooling is carried out using strong wind and water mist; after peeling, a finished large-sized casting rod with a diameter of 760 mm is obtained; after sawing, a rod material with a length of 2500 mm is obtained;

[0070] The forging process conditions are as follows: the initial forging temperature is 520 °C, and the final forging temperature is 370 °C; through upsetting and drawing forging, the upsetting and drawing forging ratio is 3.62, and the deformation amount each time is 72%, and after forging, trimming and grinding are carried out to obtain an aluminum alloy square bar with a length of 3200 mm;

[0071] The hot rolling process conditions are as follows: the hot rolling temperature is 480 °C, and the final rolling temperature is 320 °C; the total deformation amount in the hot rolling and shaping stage is 25% to obtain an aluminum alloy thick plate; the heat treatment adopts solution heat treatment, and the process conditions are: holding temperature is 515 °C, holding time is 10 h; then quenching treatment is carried out, and the quenching water temperature is 35 °C;

[0072] The aging process conditions are as follows: aging temperature is 175 °C, aging time is 8 h;

[0073] Straightening and shearing are carried out to process the aluminum alloy thick plate into a piece with dimensions of 320 (±0.5) * 1200 (±0.5) * 4200 (±1) mm;

[0074] The aluminum alloy thick plate includes the following mass percentage components: silicon Si: 0.54%; iron Fe: 0.07%; copper Cu: 0.32%; manganese Mn: 0.12%; magnesium Mg: 0.98%; chromium Cr: 0.33%; zinc Zn: 0.21%; titanium Ti: 0.08%; the balance is aluminum Al;

[0075] (2) Post-treatment:

[0076] The high-performance aluminum alloy thick plate is successively polished with 240-mesh, 600-mesh, 1500-mesh, and 2000-mesh sandpapers for 15 s; washed and dried;

[0077] Using 304 stainless steel as the anode and [aluminum alloy] as the cathode, place them in an electrolytic polishing solution at 72°C (containing 12 wt% sodium carbonate, 4.5 wt% sodium phosphate, pH 12.5), and under a voltage of 10V, perform electrolytic polishing for 25 min; then under a voltage of 0.5V, perform electrolytic polishing for 5 min; wash with water and dry with nitrogen;

[0078] Place the thick aluminum alloy plate obtained after electrolytic polishing in an oxidation electrolyte at 23°C (containing 8 g / L sodium silicate, 2 g / L sodium phosphate, adjusted to pH 12.5 with sodium hydroxide), and under the conditions of a positive voltage of 500V, a negative voltage of 50V, a duty cycle of 40%, and a frequency of 800 Hz, perform micro-arc oxidation treatment for 25 min; wash with water and dry with nitrogen to form a micro-arc oxidation film;

[0079] Age the thick aluminum alloy plate obtained after surface oxidation in water at 70°C for 100 min. Using it as the anode and graphite as the cathode, place them in a secondary electrolytic polishing solution at 72°C (containing 12 wt% sodium carbonate, 4.5 wt% sodium phosphate, pH 9.0), and under a voltage of 0.8V, perform electrolytic polishing for 25 min; wash with water and dry with nitrogen to form an oxidation film;

[0080] Spin-coat silica sol on the surface of the thick aluminum alloy plate obtained after secondary electrolytic polishing at a spin-coating speed of 800 r / min, dry at room temperature for 24 h, heat up to 100°C at a heating rate of 0.2°C / min, hold for 100 min, and cool to room temperature to obtain a surface-oxidized thick aluminum alloy plate.

[0081] Example 2: A preparation process for a high-performance thick aluminum alloy plate, including the following preparation processes:

[0082] (1) Manufacturing:

[0083] Successively perform melting, casting, homogenization, turning, flaw detection, sawing, forging, trimming and grinding, hot rolling, heat treatment, finishing and surface prestressing treatment, aging, straightening and shearing, and secondary flaw detection on the aluminum alloy raw materials to obtain a thick aluminum alloy plate;

[0084] The melting process conditions are as follows: melting temperature 740°C, melting time 7 h; refining temperature 735°C, refining time 5.5 h; add alloying elements during refining to adjust the chemical composition, and at the same time introduce chlorine and argon to remove hydrogen elements in the aluminum alloy melt, with a ventilation time of 45 min; skim the slag before pouring, and at the same time add a grain refiner AlTi5B (wire rod), and use a 40ppi ceramic filter plate to perform tubular filtration on the aluminum alloy melt to prepare a large-sized casting rod with a diameter of 800 mm and a length of 7000 mm;

[0085] The soaking process conditions are as follows: heating up to 515°C and holding for 2 hours; then continuing to heat up to 560°C and holding for 18 hours, and then rapidly cooling with strong air and water mist; after peeling, a finished large-sized casting rod with a diameter of 760 mm is obtained; after sawing, a rod stock with a length of 2500 mm is obtained.

[0086] The forging process conditions are as follows: the initial forging temperature is 500°C and the final forging temperature is 390°C; through upsetting and drawing forging, the upsetting and drawing forging ratio is 2.52, and the deformation amount each time is 60%. After forging, trimming and grinding are carried out to obtain an aluminum alloy square rod with a length of 3200 mm.

[0087] The hot rolling process conditions are as follows: the hot rolling temperature is 495°C and the final rolling temperature is 335°C; the total deformation amount in the hot rolling shaping stage is 43%. After hot rolling, an aluminum alloy thick plate is obtained.

[0088] Solution heat treatment is adopted for heat treatment, and the process conditions are as follows: the holding temperature is 518°C and the holding time is 13 hours; then quenching treatment is carried out, and the quenching water temperature is 20°C.

[0089] The aging process conditions are as follows: the aging temperature is 178°C and the aging time is 8 hours.

[0090] The aluminum alloy thick plate is straightened and sheared into a piece with dimensions of 320(±0.5)*1200(±0.5)*4200(±1) mm.

[0091] The aluminum alloy thick plate includes the following components by mass percentage: silicon Si: 0.54%; iron Fe: 0.07%; copper Cu: 0.32%; manganese Mn: 0.12%; magnesium Mg: 0.98%; chromium Cr: 0.33%; zinc Zn: 0.21%; titanium Ti: 0.08%; the balance is aluminum Al.

[0092] (2) Post-treatment:

[0093] The high-performance aluminum alloy thick plate is successively polished with 240-mesh, 600-mesh, 1500-mesh, and 2000-mesh sandpapers for 15 s; washed and dried.

[0094] Taking it as the anode and 304 stainless steel as the cathode, it is placed in an electrolytic polishing solution (containing 15 wt% sodium carbonate, 5.0 wt% sodium phosphate, and pH of 13.0) at a temperature of 75°C. Under a voltage condition of 12 V, electrolytic polishing is carried out for 30 min; then under a voltage condition of 0.6 V, electrolytic polishing is carried out for 18 min; washed with water and dried with nitrogen.

[0095] The thick aluminum alloy plate obtained after electrolytic polishing was placed in an oxidation electrolyte at 25 °C (containing 9 g / L sodium silicate, 6 g / L sodium phosphate, and the pH was adjusted to 13.0 with sodium hydroxide). Under the conditions of a positive voltage of 500 V, a negative voltage of 50 V, a duty cycle of 45%, and a frequency of 900 Hz, micro-arc oxidation treatment was carried out for 30 min; then it was washed with water and dried with nitrogen to form a micro-arc oxidation film;

[0096] The thick aluminum alloy plate obtained after surface oxidation was placed in water at 75 °C for aging for 120 min. As the anode and graphite as the cathode, it was placed in a secondary electrolytic polishing solution at 75 °C (containing 15 wt% sodium carbonate, 5 wt% sodium phosphate, and pH of 11.0). Under the voltage condition of 1.1 V, electrolytic polishing was carried out for 27 min; then it was washed with water and dried with nitrogen to form an oxidation film;

[0097] On the surface of the thick aluminum alloy plate obtained after secondary electrolytic polishing, silica sol was spin-coated at a spin-coating speed of 900 r / min, dried at room temperature for 24 h, heated to 110 °C at a heating rate of 0.3 °C / min, held for 130 min, and then cooled to room temperature to obtain a surface-oxidized thick aluminum alloy plate.

[0098] Example 3: A preparation process for a high-performance thick aluminum alloy plate, including the following preparation processes:

[0099] (1) Manufacturing:

[0100] The aluminum alloy raw materials were successively subjected to melting, casting, homogenization, turning, flaw detection, sawing, forging, trimming and grinding, hot rolling, heat treatment, finishing and surface prestressing treatment, aging, straightening and shearing, and secondary flaw detection to obtain a thick aluminum alloy plate;

[0101] The melting process conditions were: melting temperature 760 °C, melting time 8 h; refining temperature 750 °C, refining time 6 h; alloying elements were added during the refining process to adjust the chemical composition, and at the same time, chlorine and argon were introduced to remove hydrogen elements in the aluminum alloy melt, and the ventilation time was 60 min; slag was skimmed before casting, and at the same time, a grain refiner AlTi5B (wire) was added, and a 40 ppi ceramic filter plate was used to conduct tubular filtration on the aluminum alloy melt to prepare a large cast rod with a diameter of 800 mm and a length of 7000 mm;

[0102] The homogenization process conditions were: heating to 520 °C and holding for 2 h; continuing to heat to 565 °C and holding for 20 h, and then rapid cooling was carried out using strong wind and water mist; after peeling, a finished large cast rod with a diameter of 760 mm was obtained; after sawing, a rod with a length of 2500 mm was obtained;

[0103] The forging process conditions are as follows: the initial forging temperature is 480 °C, and the final forging temperature is 410 °C; after upsetting and drawing forging, the upsetting and drawing forging ratio is 1.46, and the deformation amount per time is 46%. After forging, trimming and grinding are carried out to obtain an aluminum alloy square bar with a length of 3200 mm;

[0104] The hot rolling process conditions are as follows: the hot rolling temperature is 510 °C, and the final rolling temperature is 350 °C; the total deformation amount in the hot rolling shaping stage is 60%. After hot rolling, an aluminum alloy thick plate is obtained;

[0105] Solution heat treatment is adopted for heat treatment, and the process conditions are as follows: the holding temperature is 520 °C, and the holding time is 16 h; then quenching treatment is carried out, and the quenching water temperature is 5 °C;

[0106] The aging process conditions are as follows: the aging temperature is 180 °C, and the aging time is 8 h;

[0107] The aluminum alloy thick plate is straightened and sheared into a part with dimensions of 320(±0.5)*1200(±0.5)*4200(±1) mm;

[0108] The aluminum alloy thick plate includes the following components by mass percentage: silicon Si: 0.54%; iron Fe: 0.07%; copper Cu: 0.32%; manganese Mn: 0.12%; magnesium Mg: 0.98%; chromium Cr: 0.33%; zinc Zn: 0.21%; titanium Ti: 0.08%; the balance is aluminum Al;

[0109] (2) Post-treatment:

[0110] The high-performance aluminum alloy thick plate is successively polished with 240-mesh, 600-mesh, 1500-mesh, and 2000-mesh sandpapers for 15 s; washed and dried;

[0111] As the anode and 304 stainless steel as the cathode, it is placed in an electrolytic polishing solution (containing 18 wt% sodium carbonate, 5.5 wt% sodium phosphate, and pH of 13.5) at a temperature of 78 °C. Under the voltage condition of 15 V, electrolytic polishing is carried out for 35 min; then under the voltage condition of 0.7 V, electrolytic polishing is carried out for 30 min; washed with water and dried with nitrogen;

[0112] The aluminum alloy thick plate obtained after electrolytic polishing is placed in an oxidation electrolyte at 27 °C (containing 10 g / L sodium silicate, 10 g / L sodium phosphate, and the pH is adjusted to 13.5 with sodium hydroxide). Under the conditions of a positive voltage of 500 V, a negative voltage of 50 V, a duty cycle of 50%, and a frequency of 1000 Hz, micro-arc oxidation treatment is carried out for 35 min; washed with water and dried with nitrogen to form a micro-arc oxidation film;

[0113] The thick aluminum alloy plate obtained after surface oxidation was aged in water at 80 °C for 180 min. As the anode and with graphite as the cathode, it was placed in a secondary electrolytic polishing solution at 78 °C (containing 18 wt% sodium carbonate, 5.5 wt% sodium phosphate, pH 13.0), and electrolytically polished for 30 min under a voltage condition of 1.5 V; washed with water and dried with nitrogen to form an oxide film;

[0114] On the surface of the thick aluminum alloy plate obtained after secondary electrolytic polishing, silica sol was spin-coated at a spin-coating speed of 1000 r / min, dried at room temperature for 24 h, heated to 120 °C at a heating rate of 0.5 °C / min, held for 160 min, and cooled to room temperature to obtain a surface-oxidized thick aluminum alloy plate.

[0115] Comparative Example 1: The thick aluminum alloy plate was a commercially purchased conventional heat-treated thick plate, specifically 6061-T5;

[0116] The thick aluminum alloy plate comprises the following mass percentage components: silicon Si: 0.74%; iron Fe: 0.7%; copper Cu: 0.34%; manganese Mn: 0.15%; magnesium Mg: 0.11%; chromium Cr: 0.23%; zinc Zn: 0.25%; the balance is aluminum Al.

[0117] Comparative Example 2: A preparation process for a high-performance thick aluminum alloy plate, comprising the following preparation process:

[0118] (1) The manufacturing process and process parameters are the same as those in Example 1;

[0119] (2) Post-treatment:

[0120] The high-performance thick aluminum alloy plate was successively polished with 240-mesh, 600-mesh, 1500-mesh, and 2000-mesh sandpapers for 15 s; washed and dried; as the anode and with 304 stainless steel as the cathode, it was placed in an electrolytic polishing solution at 72 °C (containing 12 wt% sodium carbonate, 4.5 wt% sodium phosphate, pH 12.5), and electrolytically polished for 25 min under a voltage condition of 10 V, washed with water and dried with nitrogen;

[0121] The thick aluminum alloy plate obtained after electrolytic polishing was placed in a micro-arc oxidation electrolyte at 23 °C (containing 8 g / L sodium silicate, 2 g / L sodium phosphate, and the pH was adjusted to 12.5 with sodium hydroxide), and micro-arc oxidation treatment was carried out for 25 min under the conditions of a positive voltage of 500 V, a negative voltage of 50 V, a duty cycle of 40%, and a frequency of 800 Hz; washed with water and dried with nitrogen to form a micro-arc oxidation film;

[0122] The thick aluminum alloy plate obtained after surface oxidation was aged in water at 70 °C for 100 min, used as the anode, with graphite as the cathode, and placed in a secondary electrolytic polishing solution at 72 °C (containing 12 wt% sodium carbonate, 4.5 wt% sodium phosphate, pH 9.0). Under a voltage condition of 0.8 V, electrolytic polishing was carried out for 25 min; then it was washed with water and dried with nitrogen to form an oxide film;

[0123] On the surface of the thick aluminum alloy plate obtained after secondary electrolytic polishing, silica sol was spin-coated at a spin-coating speed of 800 r / min, dried at room temperature for 24 h, heated to 100 °C at a heating rate of 0.2 °C / min, held for 100 min, and then cooled to room temperature to obtain a surface-oxidized thick aluminum alloy plate.

[0124] Comparative Example 3: A preparation process for a high-performance thick aluminum alloy plate, including the following preparation processes:

[0125] (1) The manufacturing process and process parameters are the same as those in Example 1;

[0126] (2) Post-treatment:

[0127] The high-performance thick aluminum alloy plate was successively polished with 240-mesh, 600-mesh, 1500-mesh, and 2000-mesh sandpapers for 15 s; washed and dried; used as the anode, with 304 stainless steel as the cathode, and placed in an electrolytic polishing solution at 72 °C (containing 12 wt% sodium carbonate, 4.5 wt% sodium phosphate, pH 12.5). Under a voltage condition of 10 V, electrolytic polishing was carried out for 25 min, then washed with water and dried with nitrogen;

[0128] The thick aluminum alloy plate obtained after electrolytic polishing was placed in an oxidation electrolyte at 23 °C (containing 8 g / L sodium silicate, 2 g / L sodium phosphate, and the pH was adjusted to 12.5 with sodium hydroxide). Under the conditions of a positive voltage of 500 V, a negative voltage of 50 V, a duty cycle of 40%, and a frequency of 800 Hz, micro-arc oxidation treatment was carried out for 25 min; washed with water and dried with nitrogen to form a micro-arc oxidation film;

[0129] The thick aluminum alloy plate obtained after surface oxidation was used as the anode, with graphite as the cathode, and placed in a secondary electrolytic polishing solution at 72 °C (containing 12 wt% sodium carbonate, 4.5 wt% sodium phosphate, pH 9.0). Under a voltage condition of 0.8 V, electrolytic polishing was carried out for 25 min; then it was washed with water and dried with nitrogen to form an oxide film;

[0130] On the surface of the thick aluminum alloy plate obtained after secondary electrolytic polishing, silica sol was spin-coated at a spin-coating speed of 800 r / min, dried at room temperature for 24 h, heated to 100 °C at a heating rate of 0.2 °C / min, held for 100 min, and then cooled to room temperature to obtain a surface-oxidized thick aluminum alloy plate.

[0131] Comparative Example 4: A preparation process for a high-performance aluminum alloy thick plate, including the following preparation process:

[0132] (1) The manufacturing process and process parameters are the same as those in Example 1;

[0133] (2) Post-treatment:

[0134] The high-performance aluminum alloy thick plate is polished with 240-mesh, 600-mesh, 1500-mesh, and 2000-mesh sandpapers in sequence for 15 s; washed and dried; used as the anode, 304 stainless steel as the cathode, placed in an electrolytic polishing solution at 72 °C (containing 12 wt% sodium carbonate, 4.5 wt% sodium phosphate, pH 12.5), and electrolytically polished for 25 min under a voltage condition of 10 V, washed with water, and dried with nitrogen;

[0135] The aluminum alloy thick plate obtained after electrolytic polishing is placed in an oxidation electrolyte at 23 °C (containing 8 g / L sodium silicate, 2 g / L sodium phosphate, and adjusted to pH 12.5 with sodium hydroxide), and micro-arc oxidation treatment is carried out for 25 min under the conditions of a positive voltage of 500 V, a negative voltage of 50 V, a duty cycle of 40%, and a frequency of 800 Hz; washed with water and dried with nitrogen to form a micro-arc oxidation film;

[0136] Spin-coat silica sol at a spin-coating speed of 800 r / min, dry at room temperature for 24 h, heat up to 100 °C at a heating rate of 0.2 °C / min, hold for 100 min, and cool to room temperature to obtain a surface-oxidized aluminum alloy thick plate.

[0137] Comparative Example 5: A preparation process for a high-performance aluminum alloy thick plate, including the following preparation process:

[0138] (1) The manufacturing process and process parameters are the same as those in Example 1;

[0139] (2) Post-treatment:

[0140] The obtained aluminum alloy thick plate is placed in an oxidation electrolyte at 23 °C (containing 8 g / L sodium silicate, 2 g / L sodium phosphate, and adjusted to pH 12.5 with sodium hydroxide), and micro-arc oxidation treatment is carried out for 25 min under the conditions of a positive voltage of 500 V, a negative voltage of 50 V, a duty cycle of 40%, and a frequency of 800 Hz; washed with water and dried with nitrogen to form a micro-arc oxidation film;

[0141] Spin-coat silica sol at a spin-coating speed of 800 r / min, dry at room temperature for 24 h, heat up to 100 °C at a heating rate of 0.2 °C / min, hold for 100 min, and cool to room temperature to obtain a surface-oxidized aluminum alloy thick plate.

[0142] Experiment: Take the aluminum alloy thick plates and surface-oxidized aluminum alloy thick plates obtained in Examples 1-3 and Comparative Examples 1-5, prepare specimens, and detect and record the test results of their properties respectively:

[0143] Mechanical property experiment: With reference to GB / T 228.1-2010, an electronic universal testing machine was used to detect the tensile strength, yield property, and elongation of the thick aluminum alloy plate specimens in the longitudinal, transverse, and height directions.

[0144] Hardness test: With reference to GB / T 231-2018, the Brinell hardness of the surface and 1 / 4 thickness of the thick aluminum alloy plate specimens was tested respectively.

[0145]

[0146]

[0147] According to the data in the above table, the following conclusions can be clearly obtained:

[0148] The thick aluminum alloy plates obtained in Examples 1-3 were compared with the thick aluminum alloy plate obtained in Comparative Example 1. The test results show that the thick aluminum alloy plates obtained in Examples 1-3 have higher tensile strength, yield strength, elongation, and Brinell hardness data, which fully demonstrates that the present invention has achieved the improvement of the mechanical properties, hardness, etc. of the prepared thick aluminum alloy plates.

[0149] And according to the drawings in the specification Figure 1-2 It shows that for the thick aluminum alloy plate obtained in Example 1, its alloy compounds were not fully dissolved, the alloying elements were not fully homogenized in the structure, and the strengthening phases precipitated densely and uniformly in the grains after heat treatment.

[0150] While according to the drawings in the specification Figure 3-4 It shows that for the thick aluminum alloy plate obtained in Comparative Example 1, its alloy compounds were fully dissolved, the alloying elements were fully homogenized in the structure, the strengthening phases precipitated sparsely in the grains after heat treatment, and severe segregation occurred inside and outside the grain boundaries.

[0151] Hardness test: A microhardness tester was used to test the Vickers hardness of the surface of the oxidized thick aluminum alloy plate specimens.

[0152] Wear resistance experiment: A reciprocating friction and wear testing machine was used to conduct a wear resistance experiment on the oxidized thick aluminum alloy plate specimens. The grinding ball was SiN with a diameter of 4 mm, the friction load was 5 N, and the friction speed was 10 mm / sec.

[0153] Impact resistance experiment: A steel ball with a mass of 1 kg was used to impact the oxidized thick aluminum alloy plate specimens in a free-fall manner from a height of 30 cm.

[0154]

[0155]

[0156] Based on the data in the above table, the following conclusions can be clearly obtained:

[0157] The surface-oxidized aluminum alloy thick plates obtained in Examples 1-3 are compared with the surface-oxidized aluminum alloy thick plates obtained in Comparative Examples 2-5. From the test results,

[0158] Compared with Example 1, the electrolytic polishing process in Comparative Example 2 is different; the electrolytic polishing process in Comparative Example 3 is different and hot water aging is not carried out; the electrolytic polishing process in Comparative Example 4 is different and hot water aging and secondary electrolytic polishing are not carried out; only micro-arc oxidation and sol sealing are carried out in Comparative Example 5. For the surface-oxidized aluminum alloy thick plate in Example 1, its surface film layer (oxidation film) has higher hardness, lower weight loss rate and impact depth data. It can be seen that the setting of the oxidation film preparation process and the components prepared in the present invention can promote the improvement of its hardness, wear resistance and impact resistance.

[0159] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0160] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation process for thick aluminum alloy plates, characterized in that: It is prepared by the following steps: The aluminum alloy raw materials are successively subjected to melting, casting, homogenizing, turning, flaw detection, sawing, forging, trimming and grinding, hot rolling, heat treatment, finishing and surface prestressing treatment, aging, straightening and shearing, and secondary flaw detection to obtain an aluminum alloy thick plate; The aluminum alloy thick plate also undergoes post-treatment, and the specific process is as follows: Using the aluminum alloy thick plate as the anode and 304 stainless steel or graphite as the cathode, placing them in an electrolytic polishing solution at a temperature of 72 - 78°C, and performing electrolytic polishing for 25 - 35 minutes under a voltage condition of 10 - 15V; then performing electrolytic polishing for 5 - 30 minutes under a voltage condition of 0.5 - 0.7V; Placing it in an oxidation electrolyte at 23 - 27°C, and performing micro-arc oxidation treatment for 25 - 35 minutes under the conditions of a positive voltage of 500V, a negative voltage of 50V, a duty cycle of 40 - 50%, and a frequency of 800 - 1000Hz; washing with water and drying with nitrogen to form a micro-arc oxidation film; Placing it in water at 70 - 80°C for aging for 100 - 180 minutes, using it as the anode and 304 stainless steel or graphite as the cathode, placing them in an electrolytic polishing solution at a temperature of 72 - 78°C, and performing electrolytic polishing for 25 - 30 minutes under a voltage condition of 0.8 - 1.5V; washing with water and drying with nitrogen to form an oxidation film; Spin-coating the sol, drying at room temperature for 24 hours, slowly heating to 100 - 120°C, holding for 100 - 160 minutes, and cooling to room temperature.

2. The preparation process of an aluminum alloy thick plate according to claim 1, characterized in that: The aluminum alloy thick plate comprises the following components by mass percentage: Si: 0.50 - 0.80%; Fe: <0.15%; Cu: 0.15 - 0.40%; Mn: 0.10 - 0.15%; Mg: 0.80 - 1.20%; Cr: 0.25 - 0.35%; Zn: <0.25%; Ti: 0.02 - 0.1%; the balance is Al.

3. The preparation process of an aluminum alloy thick plate according to claim 1, characterized in that: In the homogenizing process, the process conditions are: heating to 510 - 520°C and holding for 2 hours; Continuing to heat to 555 - 565°C and holding for 16 - 20 hours.

4. The preparation process of an aluminum alloy thick plate according to claim 1, characterized in that: In the forging process, the process conditions are: the starting forging temperature is 480 - 520°C, the final forging temperature is 370 - 410°C, the upsetting and drawing forging ratio is 1.46 - 3.62, and the deformation amount per time is 46% - 72%.

5. The preparation process of an aluminum alloy thick plate according to claim 1, characterized in that: In the hot rolling process, the process conditions are: the hot rolling temperature is 480 - 510°C, the final rolling temperature is 320 - 350°C; the total deformation amount in the hot rolling shaping stage is 25 - 60%.

6. The preparation process of an aluminum alloy thick plate according to claim 1, characterized in that: In the heat treatment process, solution heat treatment is adopted, and the process conditions are: the holding temperature is 515 - 520°C, the holding time is 10 - 16 hours; then quenching treatment is carried out, and the quenching water temperature is 5 - 35°C.

7. The preparation process of an aluminum alloy thick plate according to claim 1, characterized in that: In the aging process, the process conditions are: the aging temperature is 175 - 180°C, and the aging time is 8 hours.

8. The preparation process of an aluminum alloy thick plate according to claim 1, characterized in that: The electrolytic polishing solution contains 12 - 18wt% sodium carbonate, 4.5 - 5.5wt% sodium phosphate, and the pH is 12.5 - 13.5; The oxidation electrolyte contains 8 - 10g / L sodium silicate, 2 - 10g / L sodium phosphate, and the pH is adjusted to 12.5 - 13.5 using sodium hydroxide; The secondary electrolytic polishing solution contains 12-18 wt% sodium carbonate and 4.5-5.5 wt% sodium phosphate, and the pH is 9.0-13.

0. An aluminum alloy thick plate prepared by the preparation process according to any one of claims 1-8.

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