Preparation method of wide high-strength 6000 series aluminum plate

Abstract

The application discloses a wide high-strength 6000 series aluminum plate and a preparation method thereof. The chemical components of the wide high-strength 6000 series aluminum plate are as follows in terms of mass fraction: Si 0.80-1.20%, Fe 0.10-0.30%, Cu 0.60-0.90%, Mn 0.20-0.40%, Mg 0.90-1.20%, Ti 0.02-0.05%, and the rest is Al and other impurities. The plate strip is prepared from aluminum ingot, aluminum intermediate alloy ingot and electrolytic aluminum water through the steps of semi-continuous casting, heat treatment, sawing and milling, preheating, hot rolling, cold rolling, solid solution quenching and aging. The finished product of the wide high-strength 6000 series aluminum plate has a thickness of 0.5-2.0 mm, a width of 2000-3000 mm, a tensile strength of greater than or equal to 370 MPa, a yield strength of greater than or equal to 350 MPa and an elongation of greater than or equal to 10%.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy strip preparation, specifically relating to a wide, high-strength 6000 series aluminum sheet and its preparation method. Background Technology

[0002] Aluminum alloys, due to their high specific strength, good corrosion resistance, excellent machinability, and ease of recycling, have become ideal materials for lightweight structures. With the current trend towards wider and larger structural designs, the width requirements for aluminum plates are increasing, leading to larger ingot sizes. Consequently, the difference in solidification rates between the surface and core of wide, large flat ingots increases, exacerbating compositional and microstructure segregation and increasing internal stress. This is especially true for highly alloyed aluminum alloys, which face a significant risk of casting cracking.

[0003] 6000 series aluminum alloys primarily use Mg, Si, and Cu as strengthening elements, utilizing supersaturated solid solution precipitation of Mg2Si and Cu-containing phases for age strengthening. Common Al-Mg-Si aluminum alloys include 6061, 6063, and 6082, which have lower Mg and Si content or limited Cu addition, making it difficult to achieve a yield strength of 350 MPa or higher after heat treatment. To improve the strength of 6000 series aluminum alloys, strengthening elements such as Mg, Si, and Cu are often further increased. However, after alloying increases to a certain extent, not only do they fail to achieve the desired values, but they also severely reduce the material's plasticity and toughness. Furthermore, the widened solid-liquid two-phase crystallization temperature range increases the risk of casting cracks.

[0004] Patent application number 201811592681.X discloses an Al-Mg-Si-Cu-Mn alloy and its preparation method. By controlling the alloying elements such as Fe≤0.10%, Mn 0.08~0.18%, Mg 0.85~1.00%, Si 0.50~0.75%, and Cu 0.48~0.63% at low levels, combined with a two-stage homogenization treatment at 530~550℃ / 2~4 hours + 550~575℃ / 6~24 hours, excellent anodizing performance and a beautiful surface are obtained through extrusion. This solves the problem of easy wear and deformation under pressure caused by the moderate strength of 6061 aluminum alloy used in portable electronic devices. However, its alloy composition is relatively pure, the cost is high, the strength is limited due to the low strength of the strengthening elements, and it is limited to extrusion preparation.

[0005] Patent application number 202211329409.9 discloses a 6013 type aluminum alloy and its processing technology. It controls the alloy composition and keeps the Mn content at a low level of 0.03~0.12%, then holds it at 550~580℃ for 6~36h, and then cools it in two stages to below 60℃ before extrusion. After homogenization, the material is extruded again, and the outlet temperature of the extruded material is controlled at 500~550℃. Then, a two-stage aging process of 120~140℃ / 3~8h + 160~190℃ / 3~8h is used to ensure the strength performance of the material and improve the extrusion production efficiency. However, it is also limited to the extrusion method and does not involve wide-width aluminum alloy rolled materials.

[0006] Patent application number 201910565511.0 discloses a method for preparing ultra-wide aluminum alloy sheets. It is designed for wide 5A06 high magnesium aluminum alloys. It mainly controls the rolling process and uses a higher final rolling temperature to effectively prevent cracking at the edges of ultra-wide sheets and improve the yield of the sheets. However, it does not involve wide 6000 series aluminum alloy rolled materials.

[0007] This invention designs the alloy composition and proposes a casting and homogenization heat treatment process with reasonable proportions to avoid the risk of cracking in large-size ingots. Combined with the development of hot rolling, solution treatment, and aging processes, it obtains wide-width, high-strength 6000 series aluminum sheets. The method has simple production steps, low manufacturing cost, and meets the development requirements of large-size, high-strength structures. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a wide-width, high-strength 6000 series aluminum sheet and its preparation method, which features a reasonable process flow and low production cost.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A wide-format, high-strength 6000 series aluminum sheet is produced from aluminum ingots, intermediate alloy ingots, and molten electrolytic aluminum as raw materials. The process involves semi-continuous casting, heat treatment, sawing and milling, preheating, hot rolling, cold rolling, solution quenching, aging treatment, and tension straightening. The preparation includes the following steps:

[0011] (1) Semi-continuous casting: Prepare raw materials according to the alloy composition ratio, heat the raw materials until they are completely melted, transfer the resulting melt to a holding furnace, let it stand at 700-720℃ for 1-4 hours, then degas it online through SNIF, remove slag by deep bed filtration, and then cast it to obtain ingots.

[0012] (2) Heat treatment: The obtained ingots are subjected to homogenization heat treatment and then cooled naturally after being taken out of the furnace;

[0013] (3) Sawing and milling: Sawing and milling the ingot after homogenization and heat treatment;

[0014] (4) Preheating: Heat the milled flat ingot to 510~560℃ and keep it warm for 1~12 hours;

[0015] (5) Hot rolling: The preheated flat ingot is hot rolled continuously;

[0016] (6) Cold rolling: The hot-rolled coil obtained in step (5) is cold rolled with a single pass reduction rate of 10~40% and a finished product thickness of 0.5~2.0mm;

[0017] (7) Solution quenching: The cold-rolled coil obtained in step (6) is subjected to solution quenching in an air cushion continuous annealing furnace.

[0018] (8) Aging treatment: The quenched coil obtained in step (7) is subjected to artificial aging treatment;

[0019] (9) Stretch bending and straightening: The artificially aged coil obtained in step (8) is stretched and straightened to finally obtain the wide-width high-strength 6000 series aluminum sheet.

[0020] Further, based on a total mass percentage of 100%, the alloy composition ratio in step (1) is: Si 0.80~1.20%, Fe 0.10~0.30%, Cu 0.60~0.90%, Mn 0.20~0.40%, Mg 0.90~1.20%, Ti 0.02~0.05%, with the remainder being Al and other impurities.

[0021] Furthermore, the casting described in step (1) is carried out at a water temperature of 15-35℃ and a water flow rate of 70-150m³ / h. 3 The casting process is carried out under the following conditions: casting speed of 30-50 mm / min, casting temperature of 660-685℃, and online titanium wire addition of 30-60 ppm.

[0022] Further, after the casting in step (1) is completed, the temperature is cooled to 100°C at a rate of <40°C / h.

[0023] Furthermore, the ingot obtained in step (1) has a thickness of 600~650mm, a width of 2000~3000mm, and a length of 5000~6000mm; its hydrogen content is ≤0.14ml / 100g, and its slag content is ≤0.015mm. 2 / kg, sodium content ≤0.0005%.

[0024] Furthermore, the homogenization heat treatment in step (2) is performed at a temperature of 510~560℃ and a holding time of 4~36h.

[0025] Further, in step (5), the hot rolling process involves 13 to 17 passes of hot roughing, with an intermediate billet thickness of 20 to 30 mm, an intermediate billet temperature of ≥370℃, a final rolling thickness of 4.0 to 8.0 mm, and a final rolling temperature of 200 to 300℃.

[0026] Furthermore, the parameters for the solution quenching treatment in step (7) are 530℃~560℃ / 30~120sec, and the cooling rate is ≥5℃ / sec.

[0027] Furthermore, the parameters for the artificial aging process in step (8) are 160~180℃ / 15~25h.

[0028] Furthermore, the finished aluminum sheet has a thickness of 0.5~2.0mm, a width of 2000~3000mm, a tensile strength ≥370MPa, a yield strength ≥350MPa, and an elongation ≥10%.

[0029] The beneficial effects of this invention are as follows:

[0030] This invention avoids cracking in wide, large-size ingots by adjusting the alloy composition and designing a properly proportioned casting and homogenizing heat treatment. Combined with the development of hot rolling, solution treatment, and aging processes, it produces wide, high-strength 6000 series aluminum sheets. This method features simple production steps, low manufacturing costs, and meets the demands of large-size, high-strength structures. The resulting wide, high-strength 6000 series aluminum sheets have a finished thickness of 0.5~2.0 mm, a width of 2000~3000 mm, a tensile strength ≥370 MPa, a yield strength ≥350 MPa, and an elongation ≥10%, demonstrating promising application prospects. Attached Figure Description

[0031] Figure 1 The casting cracks on the wide aluminum sheet prepared for Comparative Example 1 are shown.

[0032] Figure 2 This is a comparison diagram of the microstructure of aluminum sheets prepared by different solution treatments in Example 2(a) and Comparative Example 2(b).

[0033] Figure 3 Comparative diagram of the microstructure of aluminum plates prepared by different homogenization heat treatments in Example 3(a) and Comparative Example 3(b). Detailed Implementation

[0034] A wide-width, high-strength 6000 series aluminum sheet is prepared by the following steps:

[0035] (1) Semi-continuous casting: Prepare raw materials according to the alloy composition ratio, heat the raw materials until they are completely melted, add intermediate alloys or additives to adjust the composition, and then transfer the resulting melt to a holding furnace, let it stand at 700-720℃ for 1-4 hours (the basic titanium content of the holding furnace is 0.015~0.20%), and then cast the ingot after degassing by SNIF online and slag removal by deep bed filtration.

[0036] (2) Heat treatment: The obtained ingots are subjected to homogenization heat treatment and then cooled naturally after being taken out of the furnace;

[0037] (3) Sawing and milling: Sawing and milling the ingot after homogenization and heat treatment;

[0038] (4) Preheating: Heat the milled flat ingot to 510~560℃ and keep it warm for 1~12 hours;

[0039] (5) Hot rolling: The preheated flat ingot is hot rolled continuously;

[0040] (6) Cold rolling: The hot-rolled coil obtained in step (5) is cold rolled with a single pass reduction rate of 10~40% and a finished product thickness of 0.5~2.0mm;

[0041] (7) Solution quenching: The cold-rolled coil obtained in step (6) is subjected to solution quenching in an air cushion continuous annealing furnace.

[0042] (8) Aging treatment: The quenched coil obtained in step (7) is subjected to artificial aging treatment;

[0043] (9) Stretch bending and straightening: The artificially aged coil obtained in step (8) is stretched and straightened to finally obtain the wide-width high-strength 6000 series aluminum sheet.

[0044] The alloy composition in step (1) is as follows, with the total mass percentage being 100%: Si 0.80~1.20%, Fe 0.10~0.30%, Cu 0.60~0.90%, Mn 0.20~0.40%, Mg 0.90~1.20%, Ti 0.02~0.05%, and the remainder being Al and other impurities.

[0045] In aluminum alloys, the Mg2Si phase and Cu-containing phase are strengthening phases. The ratio of Mg to Si has a significant impact on the material's properties. Excess Si tends to promote Mg2Si precipitation strengthening, but excessive Si can make the material hard and brittle. Considering the required strength, the optimal ratios are 0.80~1.20% Si, 0.90~1.20% Mg, and 0.60~0.90% Cu. Si and Fe are impurity elements, but appropriate amounts of Si and Fe can positively affect the prevention of casting cracks in ultra-large 6000 series aluminum alloy flat ingots. Therefore, Fe should be controlled at 0.10~0.30% and Si at 0.80~1.20%. Mn plays a role in refining grains and improving strength, but adding too much Mn can easily produce hard, polygonal primary phases. Therefore, Mn should be controlled at 0.20~0.40%. Ti is an important grain refiner in the casting process, which can improve the original grain structure. However, excessive Ti can easily lead to the aggregation of TiB2 inclusions. Therefore, Ti should be controlled. 0.02~0.05%.

[0046] The casting described in step (1) is carried out at a water temperature of 15-35℃ and a water flow rate of 70-150m³ / h. 3 The casting process is carried out under the following conditions: casting speed (single ingot) 30-50 mm / min, casting temperature 660-685℃, and online titanium wire addition 30-60 ppm. After casting, the ingot is cooled to 100℃ at a rate of <40℃ / h. The resulting ingot is 600-650 mm thick, 2000-3000 mm wide, and 5000-6000 mm long; its hydrogen content is ≤0.14 ml / 100 g, and its slag content is ≤0.015 mm. 2 / kg, sodium content ≤0.0005%.

[0047] The main causes of through cracks in ingots include hot / cold cracks, inclusion cracks, and streaking cracks. Hot cracks mainly occur in the solid-liquid zone, where dendrites are in contact with each other and the grain boundary bonding is weak. Under tensile stress, intergranular cracks are easily generated, and once formed, they are difficult to heal by the liquid metal, leading to further hot cracking. Due to uneven cooling between the large and small faces and between the surface and core metal during flat ingot casting, when the metal continues to cool after crystallization and undergoes further shrinkage, internal stress will be generated due to asymmetrical shrinkage. Internal stress accumulates until cracks appear in the flat ingot. The larger the flat ingot, the more obvious the uneven cooling, the greater the internal stress, and the greater the tendency to crack.

[0048] In semi-continuous casting, casting temperature, casting speed, water temperature, and water flow rate have a crucial impact on casting formation. Appropriate casting cooling intensity can effectively control ingot warping and ensure smooth casting. Under the same conditions, as the casting speed increases, the liquid cavity deepens, making central cracks more likely; the solidified shell thins, its strength decreases, and surface cracks are more likely to occur, potentially leading to aluminum leakage in severe cases. Therefore, the casting water temperature should be controlled between 15~35℃, and the water flow rate between 70~150 m³ / h. 3 / h (single ingot), casting speed 30~50mm / min, casting temperature 660~685℃. At the same time, in order to avoid internal stress cracking, after casting, it should be cooled to 100℃ at a rate of <40℃ / h and then subjected to homogenization heat treatment before sawing and milling.

[0049] Because sodium (melting point 97.7℃) has very low solubility in aluminum, it mainly exists in a free state on dendrite surfaces or grain boundaries. During the preheating and hot rolling of flat ingots, free sodium aggregates at grain boundaries in a molten state, forming discontinuous spherical particles. These sodium aggregation points become crack initiation sites, causing stress concentration (sodium embrittlement). Excessive hydrogen content in the melt can cause defects such as porosity and looseness in the flat ingots. The presence of inclusions in the melt not only causes defects in subsequent processed products, but severe inclusions are also a factor in casting cracks and casting failure. Therefore, it is necessary to control the hydrogen content to ≤0.14ml / 100g and the slag content to ≤0.015mm. 2 / kg, sodium content ≤0.0005%.

[0050] The homogenization heat treatment in step (2) is performed at a temperature of 510~560℃ and a holding time of 4~36h.

[0051] In step (5), the hot rolling process involves 13 to 17 passes of hot roughing, with an intermediate billet thickness of 20 to 30 mm, an intermediate billet temperature of ≥370℃, a final rolling thickness of 4.0 to 8.0 mm, and a final rolling temperature of 200 to 300℃.

[0052] To avoid excessive precipitation and coarsening of Mg2Si during hot rolling, which would prevent remelting and affect the mechanical properties of the finished product, the flat ingots are preheated at 510~560℃ for 1~12 hours before hot rolling. The intermediate hot rolling temperature is ≥370℃, and the final rolling temperature is 200~300℃.

[0053] The parameters for the solution quenching treatment in step (7) are 530℃~560℃ / 30~120sec, and the cooling rate is ≥5℃ / sec.

[0054] The parameters for the artificial aging process in step (8) are 160~180℃ / 15~25h.

[0055] High-temperature short-time solution quenching at 530℃~560℃ / 30~120sec with a cooling rate ≥5℃ / sec, and artificial aging treatment at 60~180℃ / 15~25h, enable the material to obtain good properties.

[0056] The resulting aluminum sheet has a thickness of 0.5~2.0mm, a width of 2000~3000mm, a tensile strength ≥370MPa, a yield strength ≥350MPa, and an elongation ≥10%.

[0057] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0058] Example 1

[0059] A wide-width, high-strength 6000 series aluminum sheet has the following chemical composition by mass fraction: Si 0.88%, Fe 0.24%, Cu 0.88%, Mn 0.32%, Mg 0.98%, Ti 0.035%, with the remainder being Al and other impurities, totaling 100% by mass. Its specific preparation method includes the following steps:

[0060] (1) Semi-continuous casting: Prepare raw materials according to the alloy composition ratio, heat the raw materials until they are completely melted, add intermediate alloys or additives to adjust the composition, and then transfer the resulting melt to a holding furnace, let it stand at 705℃ for 2 hours (the basic titanium content of the holding furnace is 0.016%), and then degas it online through SNIF and remove slag through deep bed filtration before casting; casting is carried out at a water temperature of 25℃ and a water flow rate of 70m³ / h. 3 The casting process was carried out at a speed of 45 mm / min and a casting temperature of 660℃, with an online titanium wire addition of 30 ppm. After casting, the ingot was cooled to 100℃ at a rate of <40℃ / h to obtain an ingot with a thickness of 650 mm, a width of 2800 mm, and a length of 6000 mm. Its hydrogen content was 0.13 ml / 100 g, and its slag content was 0.012 mm. 2 / kg, sodium content 0.0004%;

[0061] (2) Heat treatment: The obtained ingots are kept at 510℃ for 36 hours for homogenization heat treatment, and then cooled naturally after being taken out of the furnace;

[0062] (3) Sawing and milling: Sawing and milling the ingot after homogenization and heat treatment;

[0063] (4) Preheating: Heat the milled flat ingot to 530°C and keep it warm for 1 hour;

[0064] (5) Hot rolling: The preheated flat ingot is hot rolled continuously, including 17 passes of hot rough rolling, 20mm thick intermediate billet, 390℃ intermediate billet temperature, 4.0mm thick final rolling, and 220℃ final rolling temperature.

[0065] (6) Cold rolling: The hot-rolled coil obtained in step (5) is cold rolled with a single pass reduction rate of 40% and a finished product thickness of 0.5 mm;

[0066] (7) Solution quenching: The cold-rolled coil obtained in step (6) is subjected to solution quenching in an air cushion continuous annealing furnace at 530℃ / 120sec and a cooling rate of 10℃ / sec.

[0067] (8) Aging treatment: The quenched coil obtained in step (7) is subjected to artificial aging treatment at 160℃ / 25h;

[0068] (9) Stretch straightening: The artificially aged coil obtained in step (8) is stretched and straightened to finally produce a wide-width high-strength 6000 series aluminum plate. The finished product of the wide-width high-strength 6000 series aluminum plate has a thickness of 0.5 mm, a width of 2750 mm, a tensile strength of 400 MPa, a yield strength of 375 MPa, and an elongation of 11.3%.

[0069] Example 2

[0070] A wide-width, high-strength 6000 series aluminum sheet has the following chemical composition by mass fraction: Si 1.20%, Fe 0.10%, Cu 0.66%, Mn 0.27%, Mg 1.18%, Ti 0.026%, with the remainder being Al and other impurities, totaling 100% by mass. Its specific preparation method includes the following steps:

[0071] (1) Semi-continuous casting: Prepare raw materials according to the alloy composition ratio, heat the raw materials until they are completely melted, add intermediate alloys or additives to adjust the composition, and then transfer the resulting melt to a holding furnace, let it stand at 720℃ for 2 hours (the basic titanium content of the holding furnace is 0.016%), and then degas it online through SNIF and remove slag through deep bed filtration before casting; casting is carried out at a water temperature of 35℃ and a water flow rate of 145m³ / h. 3 The casting process was carried out at a rate of 40 mm / min (single ingot), a casting speed of 40 mm / min, a casting temperature of 670℃, and an online titanium wire addition of 55 ppm. After casting, the ingot was cooled to 100℃ at a rate of <40℃ / h to obtain an ingot with a thickness of 600 mm, a width of 2200 mm, and a length of 5500 mm. Its hydrogen content was 0.10 ml / 100 g, and its slag content was 0.012 mm. 2 / kg, sodium content 0.0003%;

[0072] (2) Heat treatment: The obtained ingots are kept at 560℃ for 30h for homogenization heat treatment, and then cooled naturally after being taken out of the furnace;

[0073] (3) Sawing and milling: Sawing and milling the ingot after homogenization and heat treatment;

[0074] (4) Preheating: Heat the milled flat ingot to 560℃ and keep it warm for 2 hours;

[0075] (5) Hot rolling: The preheated flat ingot is hot rolled continuously, including 13 passes of hot rough rolling, 30mm thick intermediate billet, 400℃ intermediate billet temperature, 8.0mm thick final rolling, and 270℃ final rolling temperature.

[0076] (6) Cold rolling: The hot-rolled coil obtained in step (5) is cold rolled with a single pass reduction rate of 15% and a finished thickness of 2.0 mm;

[0077] (7) Solution quenching: The cold-rolled coil obtained in step (6) is subjected to solution quenching in an air cushion continuous annealing furnace at 550℃ / 80sec and a cooling rate of 20℃ / sec.

[0078] (8) Aging treatment: The quenched coil obtained in step (7) is subjected to artificial aging treatment at 170℃ / 20h;

[0079] (9) Stretch straightening: The artificially aged coil obtained in step (8) is stretched and straightened to finally produce a wide-width high-strength 6000 series aluminum plate. The finished product of the wide-width high-strength 6000 series aluminum plate has a thickness of 2.0 mm, a width of 2170 mm, a tensile strength of 422 MPa, a yield strength of 397 MPa, and an elongation of 10.5%.

[0080] Example 3

[0081] A wide-width, high-strength 6000 series aluminum sheet has the following chemical composition by mass fraction: Si 0.93%, Fe 0.29%, Cu 0.77%, Mn 0.35%, Mg 1.15%, Ti 0.045%, with the remainder being Al and other impurities, totaling 100% by mass. Its specific preparation method includes the following steps:

[0082] (1) Semi-continuous casting: Prepare raw materials according to the alloy composition ratio, heat the raw materials until they are completely melted, add intermediate alloys or additives to adjust the composition, and then transfer the resulting melt to a holding furnace, let it stand at 715℃ for 4 hours (the basic titanium content of the holding furnace is 0.019%), and then degas it online through SNIF and remove slag through deep bed filtration before casting; casting is carried out at a water temperature of 35℃ and a water flow rate of 150m³. 3The casting process was carried out at a speed of 50 mm / min (single ingot), a casting temperature of 685℃, and an online titanium wire addition of 55 ppm. After casting, the ingot was cooled to 100℃ at a rate of <40℃ / h to obtain an ingot with a thickness of 620 mm, a width of 2500 mm, and a length of 6000 mm. Its hydrogen content was 0.09 ml / 100 g, and its slag content was 0.010 mm. 2 / kg, sodium content 0.0002%;

[0083] (2) Heat treatment: The obtained ingots are kept at 540℃ for 18 hours for homogenization heat treatment, and then cooled naturally after being taken out of the furnace;

[0084] (3) Sawing and milling: Sawing and milling the ingot after homogenization and heat treatment;

[0085] (4) Preheating: Heat the milled flat ingot to 510℃ and keep it warm for 10 hours;

[0086] (5) Hot rolling: The preheated flat ingot is hot rolled continuously, including 15 passes of hot rough rolling, with an intermediate billet thickness of 22 mm and an intermediate billet temperature of 388℃, and a final rolling thickness of 5.0 mm and a final rolling temperature of 280℃.

[0087] (6) Cold rolling: The hot-rolled coil obtained in step (5) is cold rolled with a single pass reduction rate of 15% and a finished product thickness of 1.0 mm;

[0088] (7) Solution quenching: The cold-rolled coil obtained in step (6) is subjected to solution quenching in an air cushion continuous annealing furnace at 535℃ / 120sec and a cooling rate of 12℃ / sec.

[0089] (8) Aging treatment: The quenched coil obtained in step (7) is subjected to artificial aging treatment at 180℃ / 18h;

[0090] (9) Stretch straightening: The artificially aged coil obtained in step (8) is stretched and straightened to finally produce a wide-width high-strength 6000 series aluminum plate. The finished product of the wide-width high-strength 6000 series aluminum plate has a thickness of 1.0 mm, a width of 2450 mm, a tensile strength of 405 MPa, a yield strength of 388 MPa, and an elongation of 12.3%.

[0091] Example 4

[0092] A wide-width, high-strength 6000 series aluminum sheet has the following chemical composition by mass fraction: Si 0.82%, Fe 0.28%, Cu 0.90%, Mn 0.28%, Mg 0.95%, Ti 0.028%, with the remainder being Al and other impurities, totaling 100% by mass. Its specific preparation method includes the following steps:

[0093] (1) Semi-continuous casting: Prepare raw materials according to the alloy composition ratio, heat the raw materials until they are completely melted, add intermediate alloys or additives to adjust the composition, and then transfer the resulting melt to a holding furnace, let it stand at 700℃ for 4 hours (the basic titanium content of the holding furnace is 0.018%), and then degas it online through SNIF and remove slag through deep bed filtration before casting; casting is carried out at a water temperature of 15℃ and a water flow rate of 70m³ / h. 3 The casting process was carried out at a speed of 30 mm / min and a casting temperature of 662℃, with an online titanium wire addition of 32 ppm. After casting, the ingot was cooled to 100℃ at a rate of <40℃ / h to obtain an ingot with a thickness of 625 mm, a width of 2800 mm, and a length of 5800 mm. Its hydrogen content was 0.13 ml / 100 g, and its slag content was 0.012 mm. 2 / kg, sodium content 0.0003%;

[0094] (2) Heat treatment: The obtained ingots are kept at 545℃ for 8 hours for homogenization heat treatment, and then cooled naturally after being taken out of the furnace;

[0095] (3) Sawing and milling: Sawing and milling the ingot after homogenization and heat treatment;

[0096] (4) Preheating: Heat the milled flat ingot to 515℃ and keep it warm for 2 hours;

[0097] (5) Hot rolling: The preheated flat ingot is hot rolled continuously, including 15 passes of hot rough rolling, with an intermediate billet thickness of 22 mm, an intermediate billet temperature of 415℃, a final rolling thickness of 5.0 mm, and a final rolling temperature of 300℃.

[0098] (6) Cold rolling: The hot-rolled coil obtained in step (5) is cold rolled with a single pass reduction rate of 18% and a finished product thickness of 1.5 mm;

[0099] (7) Solution quenching: The cold-rolled coil obtained in step (6) is subjected to solution quenching in an air cushion continuous annealing furnace at 532℃ / 120sec and a cooling rate of 20℃ / sec.

[0100] (8) Aging treatment: The quenched coil obtained in step (7) is subjected to artificial aging treatment at 165℃ / 25h;

[0101] (9) Stretch straightening: The artificially aged coil obtained in step (8) is stretched and straightened to finally produce a wide-width high-strength 6000 series aluminum plate. The finished product of the wide-width high-strength 6000 series aluminum plate is 1.5 mm thick, 2750 mm wide, 383 MPa tensile strength, 369 MPa yield strength, and 12.87% elongation.

[0102] Comparative Example 1

[0103] The casting temperature in step (1) is adjusted to 690℃, and the rest of the operation is the same as in Example 1.

[0104] The results showed that the casting temperature was too high and mismatched with the casting process, resulting in insufficient solidified shell in the graphite crystallizer and the appearance of hot cracks in the ingot (such as...). Figure 1 ).

[0105] Comparative Example 2

[0106] The parameters for solution quenching in step (7) are 550℃ / 20sec, and the remaining operations are the same as in Example 2.

[0107] The results showed that the finished product had a thickness of 2.0 mm, a width of 2170 mm, a tensile strength of 365 MPa, a yield strength of 337 MPa, and an elongation of 9.38%. This demonstrates that improper solution treatment significantly reduces the strength and elongation of the finished product (see...). Figure 2 ).

[0108] Comparative Example 3

[0109] The homogenization heat treatment in step (2) is performed at a temperature of 500°C for 18 hours. The remaining operations are the same as in Example 3.

[0110] The results showed that the finished product had a thickness of 1.0 mm, a width of 2450 mm, a tensile strength of 371 MPa, a yield strength of 345 MPa, and an elongation of 8.67%. This demonstrates that improper heat treatment significantly reduces the strength and elongation of the finished product (see...). Figure 3 ).

[0111] Comparative Example 4

[0112] The hot rolling final rolling temperature in step (5) is 320℃, and the remaining operations are the same as in Example 4.

[0113] The results showed that the thickness of the finished product was 1.5 mm, the width was 2750 mm, the tensile strength was 365 MPa, the yield strength was 323 MPa, and the elongation was 9.25%. It can be seen that improper hot rolling temperature will significantly reduce the strength and elongation of the finished product.

[0114] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a wide-width, high-strength 6000 series aluminum sheet, characterized in that: Includes the following steps: (1) Semi-continuous casting: Prepare raw materials according to the alloy composition ratio, heat the raw materials until they are completely melted, transfer the resulting melt to a holding furnace, let it stand at 700-720℃ for 1-4 hours, then degas it online through SNIF, remove slag by deep bed filtration, and then cast it to obtain ingots. (2) Heat treatment: The obtained ingots are subjected to homogenization heat treatment and then cooled naturally after being taken out of the furnace; (3) Sawing and milling: Sawing and milling the ingot after homogenization and heat treatment; (4) Preheating: Heat the milled flat ingot to 510~560℃ and keep it warm for 1~12 hours; (5) Hot rolling: The preheated flat ingot is hot rolled continuously; (6) Cold rolling: The hot-rolled coil obtained in step (5) is cold rolled with a single pass reduction rate of 10~40% and a finished product thickness of 0.5~2.0mm; (7) Solution quenching: The cold-rolled coil obtained in step (6) is subjected to solution quenching in an air cushion continuous annealing furnace. (8) Aging treatment: The quenched coil obtained in step (7) is subjected to artificial aging treatment; (9) Stretch bending and straightening: The artificially aged coil obtained in step (8) is stretched and straightened to finally obtain the wide-width high-strength 6000 series aluminum sheet; Based on a total mass percentage of 100%, the alloy composition in step (1) is as follows: Si 0.80~1.20%, Fe 0.10~0.30%, Cu 0.60~0.90%, Mn 0.20~0.40%, Mg 0.90~1.20%, Ti 0.02~0.05%, with the remainder being Al and other impurities; The casting described in step (1) is carried out at a water temperature of 15-35℃ and a water flow rate of 70-150m³ / h. 3 The process is carried out under the following conditions: casting speed 30~50mm / min, casting temperature 660~685℃, and online titanium wire addition 30~60ppm. The homogenization heat treatment in step (2) is performed at a temperature of 510~560℃ and a holding time of 4~36h. In step (5), the hot continuous rolling process involves 13 to 17 passes of hot roughing, with an intermediate billet thickness of 20 to 30 mm, an intermediate billet temperature of ≥370℃, a final rolling thickness of 4.0 to 8.0 mm, and a final rolling temperature of 200 to 300℃. The parameters for the solution quenching treatment in step (7) are 530℃~560℃ / 30~120sec, and the cooling rate is ≥5℃ / sec; The parameters for the artificial aging process in step (8) are 160~180℃ / 15~25h.

2. The preparation method according to claim 1, characterized in that: After casting in step (1), the temperature is cooled to 100°C at a rate of <40°C / h.

3. The preparation method according to claim 1, characterized in that: The ingot obtained in step (1) has a thickness of 600~650mm, a width of 2000~3000mm, and a length of 5000~6000mm; its hydrogen content is ≤0.14ml / 100g, and its slag content is ≤0.015mm. 2 / kg, sodium content ≤0.0005%.

4. The preparation method according to claim 1, characterized in that: The resulting aluminum sheet has a thickness of 0.5~2.0mm, a width of 2000~3000mm, a tensile strength ≥370MPa, a yield strength ≥350MPa, and an elongation ≥10%.

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