A method for preparing 6061 aluminum alloy sheet and large-size aluminum alloy sheet for semiconductors

Abstract

The invention discloses a method for preparing a 6061 aluminum alloy plate and a large-size aluminum alloy plate for semiconductors, including batching, smelting, casting, homogenization, blanking, rolling, solution quenching, pre-stretching, and aging processes; the batching process is based on the chemical composition of the 6061 aluminum alloy plate, wherein the weight percentage of Fe is 0.06-0.15%; after the batching is completed, smelting and casting are performed to obtain an aluminum alloy ingot; after the casting is completed, homogenization and blanking are performed, and in the blanking process: the aluminum alloy ingot is subjected to upsetting treatment along the length direction of the ingot; the aluminum alloy ingot after blanking is subjected to rolling treatment; in the rolling process, the initial single-pass deformation amount is greater than the subsequent single-pass deformation amount; after the rolling treatment, a large-size aluminum alloy plate is obtained; the large-size aluminum alloy plate is subjected to solution quenching, pre-stretching, and aging treatment. The plate prepared by the present invention meets the corrosion resistance requirements of the plate for semiconductor equipment.

Description

Technical Field

[0001] The invention relates to the field of aluminum alloy plate preparation, and in particular to a 6061 aluminum alloy plate preparation method and a large-size aluminum alloy plate for semiconductors. Background Art

[0002] 6061 aluminum alloy is the main material for semiconductor equipment. It has a special service environment and has high requirements for corrosion resistance. At present, there are two methods for preparing 6061 sheets for semiconductors: forging and rolling. The forging process is more complicated and requires multiple forgings. The production efficiency and batch stability are low. The rolling process has high production efficiency and good batch stability. Therefore, it has gradually become the main production process for sheets for existing semiconductor equipment.

[0003] In recent years, the demand for large-sized plates (thickness greater than 150mm) in semiconductor equipment has increased. When large-sized plates are produced by rolling process, coarse grain structure and coarse compounds in the core of the plate and corrosion performance not meeting the standard have appeared. In order to solve such problems, R&D personnel have conducted a lot of research on this. Some researchers have tried to use small-thickness flat ingots. Generally speaking, the use of small-thickness flat ingots can reduce the grain structure and compounds of the ingot material itself, but when producing large-sized plates, it is easy to cause small rolling deformation, incomplete rolling of the core structure, coarse core structure, and inability to crush the compounds, which cannot meet the use requirements; some researchers have also tried to use large-sized flat ingots. The large-sized flat ingots have large rolling deformation and sufficient deformation of the core structure, but when producing large-sized plates, due to the segregation of large-sized flat ingots, the coarse grain structure and compounds of the ingot itself, the final prepared plates cannot meet the use requirements. In addition, studies have shown that using ultra-high purity aluminum as raw material can reduce the generation of coarse compounds, but on the one hand, it brings about a significant increase in raw material costs, and on the other hand, it still cannot solve the problem of coarse grain structure of the product. In addition, industry researchers have carried out a series of optimizations on production processes such as annealing, rolling, and heat treatment, but none of them can stably solve the above problems.

[0004] Therefore, the present invention aims to provide a method for preparing a 6061 aluminum alloy sheet to better meet practical needs. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for preparing a 6061 aluminum alloy plate to solve the problems of coarse core grain structure, coarse compounds and substandard corrosion resistance of large-size aluminum alloy plates used in existing semiconductor equipment.

[0006] The technical problem solved by the present invention is to provide a large-size aluminum alloy plate for semiconductors with corrosion resistance meeting the standards.

[0007] The technical problem solved by the present invention is achieved by adopting the following technical solutions:

[0008] A method for preparing a 6061 aluminum alloy plate includes batching, smelting, casting, homogenization, blanking, rolling, solution quenching, pre-stretching, and aging processes; wherein:

[0009] In the batching process, the batching is based on the chemical composition of the 6061 aluminum alloy sheet, in which the weight percentage of Fe is 0.06~0.15%;

[0010] After the ingredients are prepared, they are melted and cast to obtain aluminum alloy ingots with a thickness of 350-420 mm.

[0011] After casting, homogenization and blanking are performed. In the blanking process: the aluminum alloy ingot is upset along the length direction of the ingot to increase the thickness of the aluminum alloy ingot;

[0012] The aluminum alloy ingot after billet making is subjected to rolling treatment; in the rolling process, the initial single-pass deformation is greater than the subsequent single-pass deformation; after the rolling treatment, a large-size aluminum alloy plate is obtained;

[0013] The large-sized aluminum alloy plates are subjected to solution quenching, pre-stretching and aging treatment.

[0014] Furthermore, in the billet making process, the aluminum alloy ingot is upset along the length direction of the ingot, so that the aluminum alloy ingot is upset from the original thickness of 350-420 mm to 600-720 mm, and the upsetting temperature is 480-540°C.

[0015] Furthermore, in the rolling process, in the initial rolling passes that are 30 to 50 mm thicker than the aluminum alloy plate to be obtained, the deformation amount of a single pass is 30 to 70 mm; in the rolling passes that are 30 to 50 mm thicker than the aluminum alloy plate to be obtained, the deformation amount of a single pass is 5 to 20 mm.

[0016] Furthermore, 2 to 3 refinings are carried out in the smelting process, the refining temperature is 740 to 760°C, each refining time is 20 to 40 minutes, each refining is allowed to stand for 20 to 40 minutes and then slag is removed, and the melt is subjected to air brick refining for the last time of standing and slag removal. During the air brick refining, the air brick pressure is 700-850KPa, and the air brick flow rate is 60-90L / min.

[0017] Furthermore, in the casting process, semi-continuous direct chill casting is adopted, and the casting speed is 38~55mm / min. The aluminum alloy ingot obtained after casting has a thickness of 350~420mm, a width of 1300~1700mm, and a length of 3500~5000mm.

[0018] Furthermore, in the homogenization process, the temperature is raised to 540-570°C and then maintained at this temperature for 12-20 hours.

[0019] Furthermore, in the rolling process, the aluminum alloy ingot is heated to 440-520°C, kept warm for 3-6 hours, and then rolled.

[0020] Furthermore, in the solution quenching process, the large-sized aluminum alloy plate is heated to 510~540℃, kept warm for 2~4h, and then quenched and taken out of the furnace; in the pre-stretching process, the stretching amount of the large-sized aluminum alloy plate is 1~3%; in the aging treatment process, the aging system is 170~190℃, and kept warm for 6~12h.

[0021] A large-size aluminum alloy plate for semiconductors is prepared by the method described above.

[0022] Furthermore, the large-size aluminum alloy plate has a tensile strength of >300 MPa, a yield strength of >280 MPa, an elongation of ≥10%, and a corrosion resistance time of ≥280 min after anodizing.

[0023] Beneficial effect: The method for preparing 6061 aluminum alloy plate of the present invention solves the contradiction between metallurgical quality and rolling deformation caused by ingot specifications at low cost by controlling the Fe content during batching, performing thickening and upsetting treatment on forged billets, and performing initial single-pass large deformation rolling deformation treatment, in combination with other processes. In this process, the problem of increased plasticity of the ingot during the manufacturing process is solved, and the refinement of internal grains and compounds is promoted to solve the problem of core structure of thick plates, thereby meeting the corrosion resistance requirements of plates for semiconductor equipment well.

[0024] The method for preparing 6061 aluminum alloy plates described in the present invention can use the billet making temperature of the ingot itself after the homogenization process, without the need for additional energy loss, and the plasticity of the ingot is increased after billet making. The initial single-pass large deformation process is subsequently adopted to improve the rolling efficiency. Therefore, compared with the existing conventional process, the present invention reduces costs and significantly improves product quality.

[0025] The large-size aluminum alloy plate for semiconductors described in the present invention has a thickness greater than 150 mm, a tensile strength greater than 300 MPa, a yield strength greater than 280 MPa, an elongation greater than 10%, and a corrosion resistance time greater than 280 min after anodization. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the SEM microstructure of the large-sized aluminum alloy plate prepared in Example 1.

[0027] Figure 2 This is the metallographic structure diagram of the large-sized aluminum alloy plate prepared in Example 1.

[0028] Figure 3 This is the SEM microstructure of the large-sized aluminum alloy plate prepared in Example 2.

[0029] Figure 4 This is the metallographic structure diagram of the large-sized aluminum alloy plate prepared in Example 2.

[0030] Figure 5 This is the SEM microstructure of the large-sized aluminum alloy plate prepared in Control Example 1.

[0031] Figure 6 This is the metallographic structure diagram of the large-sized aluminum alloy plate prepared in Control Example 1.

[0032] Figure 7 This is the SEM microstructure of the large-sized aluminum alloy plate prepared in Control Example 2.

[0033] Figure 8 This is the metallographic structure diagram of the large-sized aluminum alloy plate prepared in Control Example 2.

[0034] Fig. 9 This is the SEM microstructure of the large-sized aluminum alloy plate prepared in Control Example 3.

[0035] Fig.10 This is the metallographic structure diagram of the large-sized aluminum alloy plate prepared in Control Example 3.

[0036] Fig.11 This is the SEM microstructure of the large-sized aluminum alloy plate prepared in Control Example 4.

[0037] Fig.12 This is the metallographic structure diagram of the large-sized aluminum alloy plate prepared in Control Example 4. DETAILED DESCRIPTION

[0038] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0039] Example 1

[0040] The method for preparing the 6061 aluminum alloy sheet of the present invention comprises:

[0041] Ingredients: Aluminum ingots, copper ingots, aluminum-silicon master alloys, aluminum-chromium master alloys, and magnesium ingots are used as raw materials. The ingredients are prepared based on the chemical composition of 6061 aluminum alloy plates. The weight percentage is Mg 0.95%, Si 0.58%, Cu 0.3%, Cr0.2%, Fe 0.1%, and the balance is Al, totaling 100%;

[0042] Melting: Put aluminum ingots, copper ingots, aluminum silicon master alloys, and aluminum chromium master alloys into the melting furnace, heat and melt them, and add magnesium ingots when the melt temperature reaches 730℃. Then use a magnesium frame to scald and add them. Then use a refining agent to perform two refinings, the refining temperature is 750℃, and the refining time is 30 minutes each time. After each refining, let it stand for 30 minutes and then stand and slag. After the last standing and slag removal, pour the melt from the melting furnace into the insulation furnace through the launder. During the pouring process, open the air brick refining. During the air brick refining, the air brick pressure is 750KPa and the air brick flow rate is 80L / min.

[0043] Casting: In this step, the crystallizer thickness specification is selected to be 400mm, and the aluminum liquid after refining, degassing and deslagging is introduced into the crystallizer through the launder for semi-continuous direct cooling casting. The casting speed is 42mm / min, and the aluminum alloy ingot specification is 400mm×1600mm×4000mm;

[0044] Homogenization: The aluminum alloy ingot is sent to the soaking furnace for homogenization. The temperature is raised to 560℃ and kept for 16 hours. After homogenization, the aluminum alloy ingot is transferred to the forging platform for billet making.

[0045] Ingot making: The aluminum alloy ingot is upset along the length direction of the ingot at an upsetting temperature of 520°C, so that the aluminum alloy ingot is upset from the original thickness of 400mm to 650mm.

[0046] Rolling: Before rolling, the upset aluminum alloy ingot is milled for segregation layer, with a single-side milling of about 10 mm, and then the aluminum alloy ingot is heated to 480°C and kept warm for 4 hours. After the insulation is completed, the aluminum alloy ingot is transferred to the rolling mill for rolling, with a single-pass deformation of 40 mm, and rolled to a thickness of 230 mm, and then with a single-pass deformation of 10 mm, rolled to a final thickness of 180 mm. After rolling treatment, large-size aluminum alloy plates are obtained.

[0047] Solution quenching: Place large-sized aluminum alloy plates in a roller hearth furnace, heat to 520°C, keep warm for 2 hours, and quench out of the furnace after the insulation ends.

[0048] Pre-stretching: The large-sized aluminum alloy plates that have been solution-quenched are stretched and straightened with a stretching amount of 1.5%.

[0049] Aging process: The pre-stretched large-size aluminum alloy plates are subjected to aging treatment at 180°C and kept warm for 8 hours.

[0050] like Figure 1 and Figure 2 As shown, the large-sized aluminum alloy plate prepared in this embodiment has no coarse compounds in the core of the plate and the core grains are fine.

[0051] Example 2

[0052] The method for preparing the 6061 aluminum alloy sheet of the present invention comprises:

[0053] Ingredients: Aluminum ingots, copper ingots, aluminum-silicon master alloys, aluminum-chromium master alloys, and magnesium ingots are used as raw materials. The ingredients are prepared based on the chemical composition of 6061 aluminum alloy plates. The weight percentage is Mg 0.95%, Si 0.58%, Cu 0.3%, Cr0.2%, Fe 0.1%, and the balance is Al, totaling 100%;

[0054] Melting: Put aluminum ingots, copper ingots, aluminum silicon master alloys, and aluminum chromium master alloys into the melting furnace, heat and melt, and add magnesium ingots when the melt temperature reaches 740℃. Then use a magnesium frame to scald and add. Then use a refining agent to perform two refinings, the refining temperature is 740℃, each refining time is 40min, and each refining is allowed to stand for 30min and then stand for slag removal. After the last standing and slag removal, pour the melt from the melting furnace into the insulation furnace through the launder. During the pouring process, open the air brick refining. During the air brick refining, the air brick pressure is 800KPa and the air brick flow rate is 70L / min.

[0055] Casting: In this step, the crystallizer thickness specification is selected to be 350mm. The aluminum liquid after refining, degassing and deslagging is introduced into the crystallizer through the launder for semi-continuous direct cooling casting. The casting speed is 50mm / min, and the aluminum alloy ingot specification is 350mm×1600mm×4000mm.

[0056] Homogenization: The aluminum alloy ingot is sent to the soaking furnace for homogenization. During homogenization, the temperature is raised to 540℃ and kept for 20 hours. After homogenization, the aluminum alloy ingot is transferred to the forging platform for billet making.

[0057] Ingot making: The aluminum alloy ingot is upset along the length direction of the ingot at an upsetting temperature of 520°C, so that the aluminum alloy ingot is upset from the original thickness of 350 mm to 610 mm.

[0058] Rolling: Before rolling, the upset aluminum alloy ingot is milled for segregation layer, with a single-side milling of about 10 mm, and then the aluminum alloy ingot is heated to 480°C and kept warm for 4 hours. After the insulation is completed, the aluminum alloy ingot is transferred to the rolling mill for rolling, with a single-pass deformation of 50 mm, and rolled to a thickness of 240 mm, and then with a single-pass deformation of 20 mm, rolled to a final thickness of 180 mm. After rolling treatment, large-size aluminum alloy plates are obtained.

[0059] Solution quenching: Place large-sized aluminum alloy plates in a roller hearth furnace, heat to 520°C, keep warm for 2 hours, and quench out of the furnace after the insulation ends.

[0060] Pre-stretching: The large-sized aluminum alloy plates that have been solution-quenched are stretched and straightened with a stretching amount of 1.5%.

[0061] Aging process: The pre-stretched large-size aluminum alloy plates are subjected to aging treatment at 180°C and kept warm for 8 hours.

[0062] like Figure 3 and Figure 4 As shown, the large-sized aluminum alloy plate prepared in this embodiment has no coarse compounds in the core of the plate and the core grains are fine.

[0063] Comparative Example 1

[0064] The method for preparing the 6061 aluminum alloy sheet described in this comparative example comprises:

[0065] Ingredients: Aluminum ingots, copper ingots, aluminum-silicon master alloys, aluminum-chromium master alloys, and magnesium ingots are used as raw materials. The ingredients are prepared based on the chemical composition of 6061 aluminum alloy plates. The weight percentage is Mg 0.95%, Si 0.58%, Cu 0.3%, Cr0.2%, Fe 0.1%, and the balance is Al, totaling 100%;

[0066] Melting: Put aluminum ingots, copper ingots, aluminum silicon master alloys, and aluminum chromium master alloys into the melting furnace, heat and melt them, and add magnesium ingots when the melt temperature reaches 730℃. Then use a magnesium frame to scald and add them. Then use a refining agent to perform two refinings, the refining temperature is 750℃, and the refining time is 30 minutes each time. After each refining, let it stand for 30 minutes and then stand and slag. After the last standing and slag removal, pour the melt from the melting furnace into the insulation furnace through the launder. During the pouring process, open the air brick refining. During the air brick refining, the air brick pressure is 750KPa and the air brick flow rate is 80L / min.

[0067] Casting: In this step, the crystallizer thickness specification is selected to be 400mm, and the aluminum liquid after refining, degassing and deslagging is introduced into the crystallizer through the launder for semi-continuous direct cooling casting. The casting speed is 42mm / min, and the aluminum alloy ingot specification is 400mm×1600mm×4000mm;

[0068] Homogenization: The aluminum alloy ingot is sent to the soaking furnace for homogenization. During homogenization, the temperature is raised to 560℃ and kept warm for 16 hours.

[0069] Rolling: Before rolling, the homogenized aluminum alloy ingot is milled for segregation layer, with a single-side milling of about 10 mm, and then the aluminum alloy ingot is heated to 480°C and kept warm for 4 hours. After the insulation is completed, the aluminum alloy ingot is transferred to the rolling mill for rolling, with a single-pass deformation of 40 mm, and rolled to a thickness of 230 mm, and then with a single-pass deformation of 10 mm, rolled to a final thickness of 180 mm. After rolling, large-size aluminum alloy plates are obtained.

[0070] Solution quenching: Place large-sized aluminum alloy plates in a roller hearth furnace, heat to 520°C, keep warm for 2 hours, and quench out of the furnace after the insulation ends.

[0071] Pre-stretching: The large-sized aluminum alloy plates that have been solution-quenched are stretched and straightened with a stretching amount of 1.5%.

[0072] Aging process: The pre-stretched large-size aluminum alloy plates are subjected to aging treatment at 180°C and kept warm for 8 hours.

[0073] like Figure 5 and Figure 6 As shown, the large-sized aluminum alloy plate prepared in this comparative example has coarse compounds in the core of the plate and coarse grains in the core.

[0074] Comparative Example 2

[0075] The method for preparing the 6061 aluminum alloy sheet of the present invention comprises:

[0076] Ingredients: Aluminum ingots, copper ingots, aluminum-silicon master alloys, aluminum-chromium master alloys, and magnesium ingots are used as raw materials. The ingredients are prepared based on the chemical composition of 6061 aluminum alloy plates. The weight percentage is Mg 0.95%, Si 0.58%, Cu 0.3%, Cr0.2%, Fe 0.1%, and the balance is Al, totaling 100%;

[0077] Melting: Put aluminum ingots, copper ingots, aluminum silicon master alloys, and aluminum chromium master alloys into the melting furnace, heat and melt them, and add magnesium ingots when the melt temperature reaches 730℃. Then use a magnesium frame to scald and add them. Then use a refining agent to perform two refinings, the refining temperature is 750℃, and the refining time is 30 minutes each time. After each refining, let it stand for 30 minutes and then stand and slag. After the last standing and slag removal, pour the melt from the melting furnace into the insulation furnace through the launder. During the pouring process, open the air brick refining. During the air brick refining, the air brick pressure is 750KPa and the air brick flow rate is 80L / min.

[0078] Casting: In this step, the crystallizer thickness specification is selected as 520mm. The aluminum liquid after refining, degassing and deslagging is introduced into the crystallizer through the launder for semi-continuous direct cooling casting. The casting speed is 40mm / min, and the aluminum alloy ingot specification is 520mm×1600mm×4000mm.

[0079] Homogenization: The aluminum alloy ingot is sent to the soaking furnace for homogenization. The temperature is raised to 560℃ and kept for 16 hours. After homogenization, the aluminum alloy ingot is transferred to the forging platform for billet making.

[0080] Ingot making: The aluminum alloy ingot is upset along the length direction of the ingot at an upsetting temperature of 520°C, so that the aluminum alloy ingot is upset from an original thickness of 520 mm to 650 mm.

[0081] Rolling: Before rolling, the upset aluminum alloy ingot is milled for segregation layer, with a single-side milling of about 10 mm, and then the aluminum alloy ingot is heated to 480°C and kept warm for 4 hours. After the insulation is completed, the aluminum alloy ingot is transferred to the rolling mill for rolling, with a single-pass deformation of 40 mm, and rolled to a thickness of 230 mm, and then with a single-pass deformation of 10 mm, rolled to a final thickness of 180 mm. After rolling treatment, large-size aluminum alloy plates are obtained.

[0082] Solution quenching: Place large-sized aluminum alloy plates in a roller hearth furnace, heat to 520°C, keep warm for 2 hours, and quench out of the furnace after the insulation ends.

[0083] Pre-stretching: The large-sized aluminum alloy plates that have been solution-quenched are stretched and straightened with a stretching amount of 1.5%.

[0084] Aging process: The pre-stretched large-size aluminum alloy plates are subjected to aging treatment at 180°C and kept warm for 8 hours.

[0085] like Figure 7 and Figure 8 As shown, the large-sized aluminum alloy plate prepared in this comparative example has coarse compounds in the core of the plate and coarse grains in the core.

[0086] Comparative Example 3

[0087] The method for preparing the 6061 aluminum alloy sheet of the present invention comprises:

[0088] Ingredients: Aluminum ingots, copper ingots, aluminum-silicon master alloys, aluminum-chromium master alloys, and magnesium ingots are used as raw materials. The ingredients are prepared based on the chemical composition of 6061 aluminum alloy plates. The weight percentage is Mg 0.95%, Si 0.58%, Cu 0.3%, Cr0.2%, Fe 0.1%, and the balance is Al, totaling 100%;

[0089] Melting: Put aluminum ingots, copper ingots, aluminum silicon master alloys, and aluminum chromium master alloys into the melting furnace, heat and melt them, and add magnesium ingots when the melt temperature reaches 730℃. Then use a magnesium frame to scald and add them. Then use a refining agent to perform two refinings, the refining temperature is 750℃, and the refining time is 30 minutes each time. After each refining, let it stand for 30 minutes and then stand and slag. After the last standing and slag removal, pour the melt from the melting furnace into the insulation furnace through the launder. During the pouring process, open the air brick refining. During the air brick refining, the air brick pressure is 750KPa and the air brick flow rate is 80L / min.

[0090] Casting: In this step, the crystallizer thickness specification is selected to be 400mm, and the aluminum liquid after refining, degassing and deslagging is introduced into the crystallizer through the launder for semi-continuous direct cooling casting. The casting speed is 42mm / min, and the aluminum alloy ingot specification is 400mm×1600mm×4000mm;

[0091] Homogenization: The aluminum alloy ingot is sent to the soaking furnace for homogenization. The temperature is raised to 560℃ and kept for 16 hours. After homogenization, the aluminum alloy ingot is transferred to the forging platform for billet making.

[0092] Ingot making: The aluminum alloy ingot is upset along the length direction of the ingot at an upsetting temperature of 520°C, so that the aluminum alloy ingot is upset from the original thickness of 400mm to 650mm.

[0093] Rolling: Before rolling, the upset aluminum alloy ingot is milled for segregation layer, with a single-side milling of about 10 mm, and then the aluminum alloy ingot is heated to 480°C and kept warm for 4 hours. After the insulation is completed, the aluminum alloy ingot is transferred to the rolling mill for rolling, with a single-pass deformation of 20 mm, and rolled to a thickness of 230 mm, and then with a single-pass deformation of 10 mm, rolled to a final thickness of 180 mm. After rolling treatment, large-size aluminum alloy plates are obtained.

[0094] Solution quenching: Place large-sized aluminum alloy plates in a roller hearth furnace, heat to 520°C, keep warm for 2 hours, and quench out of the furnace after the insulation ends.

[0095] Pre-stretching: The large-sized aluminum alloy plates that have been solution-quenched are stretched and straightened with a stretching amount of 1.5%.

[0096] Aging process: The pre-stretched large-size aluminum alloy plates are subjected to aging treatment at 180°C and kept warm for 8 hours.

[0097] like Fig. 9 and Fig.10 As shown, the large-sized aluminum alloy plate prepared in this comparative example has coarse compounds in the core of the plate and coarse grains in the core.

[0098] Comparative Example 4

[0099] The method for preparing the 6061 aluminum alloy sheet described in this comparative example comprises:

[0100] Ingredients: Aluminum ingots, copper ingots, aluminum-silicon master alloys, aluminum-chromium master alloys, and magnesium ingots are used as raw materials. The ingredients are prepared based on the chemical composition of 6061 aluminum alloy plates. The weight percentage is Mg 0.95%, Si 0.58%, Cu 0.3%, Cr0.2%, Fe 0.2%, and the balance is Al, totaling 100%;

[0101] Melting: Put aluminum ingots, copper ingots, aluminum silicon master alloys, and aluminum chromium master alloys into the melting furnace, heat and melt them, and add magnesium ingots when the melt temperature reaches 730℃. Then use a magnesium frame to scald and add them. Then use a refining agent to perform two refinings, the refining temperature is 750℃, and the refining time is 30 minutes each time. After each refining, let it stand for 30 minutes and then stand and slag. After the last standing and slag removal, pour the melt from the melting furnace into the insulation furnace through the launder. During the pouring process, open the air brick refining. During the air brick refining, the air brick pressure is 750KPa and the air brick flow rate is 80L / min.

[0102] Casting: In this step, the crystallizer thickness specification is selected to be 400mm, and the aluminum liquid after refining, degassing and deslagging is introduced into the crystallizer through the launder for semi-continuous direct cooling casting. The casting speed is 42mm / min, and the aluminum alloy ingot specification is 400mm×1600mm×4000mm;

[0103] Homogenization: The aluminum alloy ingot is sent to the soaking furnace for homogenization. The temperature is raised to 560℃ and kept for 16 hours. After homogenization, the aluminum alloy ingot is transferred to the forging platform for billet making.

[0104] Ingot making: The aluminum alloy ingot is upset along the length direction of the ingot at an upsetting temperature of 520°C, so that the aluminum alloy ingot is upset from the original thickness of 400mm to 650mm.

[0105] Rolling: Before rolling, the upset aluminum alloy ingot is milled for segregation layer, with a single-side milling of about 10 mm, and then the aluminum alloy ingot is heated to 480°C and kept warm for 4 hours. After the insulation is completed, the aluminum alloy ingot is transferred to the rolling mill for rolling, with a single-pass deformation of 40 mm, and rolled to a thickness of 230 mm, and then with a single-pass deformation of 10 mm, rolled to a final thickness of 180 mm. After rolling treatment, large-size aluminum alloy plates are obtained.

[0106] Solution quenching: Place large-sized aluminum alloy plates in a roller hearth furnace, heat to 520°C, keep warm for 2 hours, and quench out of the furnace after the insulation ends.

[0107] Pre-stretching: The large-sized aluminum alloy plates that have been solution-quenched are stretched and straightened with a stretching amount of 1.5%.

[0108] Aging process: The pre-stretched large-size aluminum alloy plates are subjected to aging treatment at 180°C and kept warm for 8 hours.

[0109] like Fig.11 and Fig.12 As shown, the large-sized aluminum alloy plate prepared in this comparative example has coarse compounds in the core of the plate.

[0110] The large-size aluminum alloy plates prepared in the embodiments and control examples were tested, wherein the mechanical properties were mainly based on the method of GB / T228.1, and the MTS E44.304 microcomputer-controlled electronic universal testing machine was used for testing; the structure inspection was mainly based on the method of GB / T3246; the corrosion resistance test method was: whether bubbles were generated in the plate anodic oxide film under the condition of 5% vol hydrochloric acid corrosion for 240 min. The results are shown in Table 1.

[0111] Table 1 Performance test results statistics

[0112]

[0113] It can be seen from Table 1 that the large-sized aluminum alloy plate described in the present invention has a tensile strength of >300 MPa, a yield strength of >280 MPa, an elongation of ≥10%, and a corrosion resistance time of ≥280 min after anodizing, which is much higher than the requirements of the existing standards for large-sized aluminum alloy plates for semiconductors. In Control Examples 1 and 2, although the mechanical properties meet the standards, the corrosion resistance cannot meet the standards and cannot be promoted and applied, indicating that the specification control of the initial billet casting and the thickening and upsetting matching treatment in the billet making process are extremely critical in the present invention. Control Examples 3 and 4 show that when the rolling process is improperly set or the Fe content in the batching process is improperly controlled, the performance and corrosion resistance of the prepared large-sized aluminum alloy plate are not good, indicating that the present invention is the result of the coordinated cooperation of multiple processes and condition control.

[0114] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a 6061 aluminum alloy sheet, characterized in that: It includes batching, smelting, casting, homogenization, billet making, rolling, solution quenching, pre-stretching and aging processes; among which: In the batching process, the batching is based on the chemical composition of the 6061 aluminum alloy sheet, which includes by weight percentage: Mg 0.8~1.2%, Si 0.5~0.7%, Cu 0.2~0.4%, Cr 0.1~0.3%, Fe 0.06~0.15%, and the balance is Al, totaling 100%; After the ingredients are prepared, they are melted and cast to obtain aluminum alloy ingots with a thickness of 350-420 mm. After casting, homogenization and blanking are carried out. In the blanking process: the aluminum alloy ingot is upset along the length direction of the ingot to increase the thickness of the aluminum alloy ingot, so that the aluminum alloy ingot is upset from the original thickness of 350~420mm to 600~720mm, and the upset temperature is 480~540℃; The aluminum alloy ingot after blanking is subjected to rolling treatment; in the rolling process, the initial single-pass deformation is greater than the subsequent single-pass deformation; in the initial rolling pass that is 30-50 mm thicker than the aluminum alloy plate to be obtained, the single-pass deformation is 30-70 mm; in the rolling pass that is 30-50 mm thicker than the aluminum alloy plate to be obtained, the single-pass deformation is 5-20 mm; after the rolling treatment, a large-size aluminum alloy plate is obtained; The large-sized aluminum alloy plates are subjected to solution quenching, pre-stretching and aging treatment.

2. The method for preparing a 6061 aluminum alloy sheet according to claim 1, characterized in that: In the smelting process, 2~3 refinings are carried out, the refining temperature is 740~760℃, each refining time is 20~40min, after each refining, let it stand for 20~40min and then slag, after the last standing and slag removal, the melt is refined with air bricks, during the air brick refining, the air brick pressure is 700-850kPa, and the air brick flow rate is 60-90L / min.

3. The method for preparing a 6061 aluminum alloy sheet according to claim 1, characterized in that: In the casting process, semi-continuous direct chill casting is adopted with a casting speed of 38~55mm / min. The aluminum alloy ingot obtained after casting has a thickness of 350~420mm, a width of 1300~1700mm, and a length of 3500~5000mm.

4. The method for preparing a 6061 aluminum alloy sheet according to claim 1, characterized in that: During the homogenization process, the temperature is raised to 540~570℃ and kept at this temperature for 12~20h.

5. The method for preparing a 6061 aluminum alloy sheet according to claim 1, characterized in that: During the rolling process, the aluminum alloy ingot is heated to 440~520℃ and kept warm for 3~6h. After the heat preservation is completed, rolling is carried out.

6. The method for preparing a 6061 aluminum alloy sheet according to claim 1, characterized in that: In the solution quenching process, the large-sized aluminum alloy plates are heated to 510~540℃, kept warm for 2~4h, and then quenched out of the furnace; in the pre-stretching process, the stretching amount of the large-sized aluminum alloy plates is 1~3%; in the aging treatment process, the aging system is 170~190℃, and kept warm for 6~12h.

7. A large-size aluminum alloy sheet for semiconductors, characterized in that: The large-size aluminum alloy plate is prepared by the method according to any one of claims 1 to 6, wherein the tensile strength of the large-size aluminum alloy plate is greater than 300 MPa, the yield strength is greater than 280 MPa, the elongation is greater than 10%, and the corrosion resistance time after anodizing is greater than 280 min.

Images