Method for low-carbon short-process large-flux production of bulging deep-drawing cooker aluminum coil

Abstract

The invention belongs to the technical field of aluminum alloy production, and particularly discloses a method for low-carbon short-process large-flux production of an expandable deep-drawing cooker aluminum coil, electrolytic aluminum water and secondary aluminum waste are used as raw materials, a continuous casting and rolling mode is adopted for production, and compared with an existing conventional hot rolling production mode, the production process can be greatly optimized, and the production efficiency is improved. In the cold rolling process, production can be completed only through two rolling passes without ingot casting head cutting and face milling and multi-pass hot rough rolling procedures, the in-process time is shortened, the production cost is effectively reduced, the performance of a finished product is more excellent, particularly, the ductility is high and stable, the transverse and longitudinal extension difference is small, and the material isotropy is good; the grain size of the blank can reach the standard without using an aluminum ingot, a terminal customer does not crack during deep punching and bulging, the green, environment-friendly and low-carbon targets are achieved, meanwhile, the stable quality of a finished product is guaranteed, large-flux production can be achieved, high-efficiency production of 27 tons or above per hour of the blank is achieved, and high-efficiency order delivery is achieved.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy production technology, and specifically discloses a method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils. Background Technology

[0002] Rice cooker inner pots can be categorized by shape into cylindrical, spherical / arc-shaped, and conical / trapezoidal inner pots. Spherical / arc-shaped inner pots are a type of expanded inner pot. Expanded inner pots require withstanding severe and complex deformation during molding, necessitating materials that simultaneously meet three core requirements: high strength and crack resistance, high plasticity and easy deformation, and uniform, defect-free structure. All three are indispensable, thus placing high demands on material performance. Currently, the aluminum alloy sheets used in expanded inner pot processing are generally produced using hot rolling. For example, Chinese patent CN111041283B uses hot rolling to produce 3003 aluminum alloy round sheets for deep-drawn expanded inner pots in rice cookers. The smelted and cast aluminum alloy ingots require homogenization treatment, hot rolling, cold rolling, annealing, and stamping processes to obtain the finished aluminum alloy round sheets. This process involves numerous steps, a long production flow, and high production costs. Summary of the Invention

[0003] To address the problems in the background art, this invention discloses a method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils. The method employs continuous casting and rolling, which significantly optimizes the production process, reduces production costs, shortens work-in-process time, and produces high-quality finished products, achieving low-carbon, high-efficiency, short-process, and high-quality production.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A low-carbon, short-process, high-throughput method for producing expandable, deep-drawing cookware aluminum coils includes the following steps: S1. Smelting: 50%–60% recycled aluminum scrap and 40%–50% molten electrolytic aluminum are placed in a smelting furnace for remelting to prepare molten aluminum. The furnace temperature is 745–755℃. Stirring is performed, and an original sample is taken for testing. Based on the test results, iron, manganese, copper, titanium, aluminum-titanium alloy, and quick-dissolving silicon are added to adjust the alloy composition to meet the requirements. The mass percentages of each component are: Si: 0.1%–0.2%, Fe: 0.3%–0.5%, Cu: 0.05%–0.1%, Mn: 0.6~0.8%, Mg≤0.01%, Zn≤0.01%, Ti: 0.02%~0.04%, total impurity elements≤0.03%, balance is aluminum; after the composition is qualified, it is refined and slag is removed. After slag removal, it is allowed to stand for 30~40 minutes before the furnace is started. The temperature of the aluminum liquid is controlled at 740~750℃ when the furnace is started. After the furnace is started, the aluminum melt flows smoothly into the guide channel. Four sets of aluminum-titanium-boron wires are added to the aluminum melt at a uniform speed. The aluminum melt enters the degassing box and plate filter box in sequence for online degassing and filtration before flowing into the front box; S2. Continuous casting and rolling: During continuous casting, the molten aluminum in the front box is injected into the casting cavity at a uniform speed through the casting nozzle. The molten aluminum in the casting cavity exits the plate as the steel strip rotates. The continuously cast slab enters the three-stand rolling mill through the looper table. The thickness at the entrance of the first stand of the three-stand rolling mill is 19mm, the thickness at the exit of the first stand of the three-stand rolling mill is 13-14mm, the thickness at the exit of the second stand of the three-stand rolling mill is 9-10mm, and the thickness at the exit of the third stand of the three-stand rolling mill is 6.5-7.5mm. The plate exiting the third stand of the three-stand rolling mill is rolled into aluminum coils. S3. Homogenization annealing: The aluminum coil obtained in S2 is homogenized and annealed. During annealing, the billet is first placed in the annealing furnace. After 4 hours, the furnace temperature is raised to 580℃ at a constant rate and held for 20-25 hours. Then, the furnace temperature is lowered to 170℃ and the coil is taken out of the furnace. After annealing, the cold-rolled coil is cooled to below 60℃ and then transferred to the subsequent production process. S4. Cold rolling: The aluminum coils after homogenization annealing are directly rolled on the cold rolling mill. The processing rate of each cold rolling pass is controlled at 45-55%. After two passes, the aluminum coils are rolled to a thickness of 1.4-2.1 mm. S5. Finished product annealing: The aluminum coil obtained in step S4 is placed in an annealing furnace for finished product annealing. The temperature is raised to 220°C at a constant rate for 2 hours, and held under negative pressure for 4 hours. Then, the temperature is raised to 420°C at a constant rate for 2 hours, and held under positive pressure for 20-25 hours before being taken out of the furnace. Then, the furnace temperature is lowered to 170°C before being taken out of the furnace and allowed to cool naturally to room temperature. S6. Testing and Packaging: The tensile strength of the finished aluminum coil shall be 85MPa~100MPa, the elongation shall be ≥45%, and the difference between the longitudinal and transverse elongation shall be within 2%. The qualified finished products shall be packaged in accordance with the packaging requirements for aluminum coils for discs.

[0005] Furthermore, in the method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils, in step S1, titanium agent and aluminum-titanium alloy are simultaneously added to the aluminum melt.

[0006] Furthermore, in the method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils, in step S1, after the melt is refined, slag removed, and allowed to stand, samples are taken from both sides of the furnace door to test the composition, with the content deviation of each alloy being less than 0.01%.

[0007] Furthermore, in the method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils, in step S1, argon refining is performed using a refining machine for 20-30 minutes. When argon is introduced into the aluminum melt for refining, the tumbling height of the aluminum melt is ≤100mm.

[0008] Furthermore, in the method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils, in step S2, the front box temperature is 685–705℃, the casting speed is 6.8–7.8 m / min, and the thickness of the cast slab is 19 mm.

[0009] Furthermore, in the method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils, in step S3, the billet aluminum coil needs to be placed on a high-level rack during homogenization annealing to ensure suspended annealing.

[0010] Furthermore, in the method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils, in step S4, the thickness tolerance of the cold-rolled finished product does not exceed ±1.5%.

[0011] Furthermore, in the method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils, in step S5, the temperature difference between different zones in the furnace during finished product annealing is within ±3℃.

[0012] Due to the adoption of the technical solution described above, the present invention has the following advantages: 1. The method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils disclosed in this invention adopts continuous casting and rolling, which can significantly optimize the production process compared with the current conventional hot rolling production method. It eliminates the need for ingot cutting and milling and multiple hot rough rolling processes. The cold rolling process only requires two rolling passes to complete the production, shortening the work-in-process time, effectively reducing production costs, and producing finished products with superior performance, especially high and stable elongation, small difference in transverse and longitudinal elongation, and good material isotropy. It prevents cracking during deep drawing and expansion for end customers, ensuring stable quality for end customers. The aluminum coils for expandable deep-drawing cookware produced using this method have good edge quality and no edge cracking problems. Therefore, the finished product does not need to be trimmed, reducing waste generation, increasing yield, and reducing production costs. 2. The method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils disclosed in this invention uses electrolytic aluminum molten aluminum and recycled aluminum waste as raw materials. It does not require the use of aluminum ingots and can meet the standard of billet grain size. While achieving green, environmentally friendly, and low-carbon goals, it ensures stable finished product quality and enables high-throughput production. The billet can be produced at a high efficiency of more than 27 tons per hour, enabling high-efficiency order delivery. Detailed Implementation

[0013] The present invention will be further explained and illustrated below with reference to embodiments. However, this should not be construed as limiting the scope of protection of the present invention. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention. Example 1

[0014] The specific steps of the low-carbon, short-process, high-throughput production method for expandable, deep-drawing aluminum coils for cookware are as follows: S1. Smelting: 41.8% recycled aluminum waste and 58.2% electrolytic aluminum liquid are placed in a smelting furnace for remelting to prepare aluminum melt. The smelting furnace temperature is 753℃. An initial sample is taken for analysis. Based on the initial sample analysis results, iron, manganese, copper, titanium, aluminum-titanium alloy, and quick-dissolving silicon are added simultaneously. Titanium and aluminum-titanium alloy are added to the aluminum melt to adjust the alloy composition to meet the requirements. The mass percentages of each component are: Si: 0.11%, Fe: 0.35%, Cu: 0.055%, Mn: 0.67%, Mg: 0.007%, Zn: 0.006%, Ti: 0.024%, with total impurities ≤ 0.03%, and the balance being aluminum. After adjustment and approval, refining and slag removal are carried out. During refining, an Hd2000 refining machine is used for argon refining, which takes 23 minutes. When argon is introduced into the aluminum melt for refining, the tumbling height of the aluminum melt is ≤100mm. After refining, slag is removed, and the liquid surface must be mirror-like. After standing for 33 minutes, the furnace is started. After refining, slag removal and standing, samples are taken from both sides of the furnace door to test the composition. The content deviation of each alloy is less than 0.01%. The temperature of the aluminum melt is controlled at 742℃ when the furnace is started. After the furnace is started, the aluminum melt flows smoothly into the guide channel. Four sets of aluminum-titanium-boron wires are added to the aluminum melt at a uniform speed. The aluminum melt enters the degassing box and plate filter box in sequence for online degassing and filtration before flowing into the front box. S2. Continuous Casting and Rolling: During continuous casting, molten aluminum in the front box is injected into the casting cavity at a uniform speed through the casting nozzle. The molten aluminum in the casting cavity exits the plate as the steel strip rotates. The inner sides of the two steel strips are connected to the circulating cooling water. The cooling water temperature is controlled at 34℃ and the cooling water pressure is controlled at 0.46MPa. The heat in the molten aluminum is carried away by the cooling water through the steel strip. During continuous casting, the front box temperature is maintained at 692℃, the casting speed is controlled at 7.0m / min, and the thickness of the cast slab is controlled at 19mm. The continuously cast slab enters the three-stand rolling mill for rolling through the looper table. During the slab rolling, emulsion is used for lubrication and cooling. The thickness at the first stand of the three-stand rolling mill is 19mm, the thickness at the first stand of the three-stand rolling mill is 13mm, the thickness at the second stand of the three-stand rolling mill is 9mm, and the thickness at the third stand of the three-stand rolling mill is 6.5mm. The strip exiting the third stand of the three-stand rolling mill is coiled into aluminum coils by a coiler. S3. Homogenization Annealing: The aluminum coils rolled up in step S2 are subjected to homogenization annealing. During annealing, the 6.5mm thick billet is first placed in the high-level rack in the annealing furnace to ensure suspended annealing. Then, the furnace temperature is raised to 580℃ for 4 hours and held for 22 hours. Then, the furnace temperature is lowered to 170℃ and the coils are taken out of the furnace. The annealed cold-rolled coils are air-cooled to 55℃ and transferred to subsequent production processes. S4. Cold rolling: After homogenization annealing, the 6.5mm thick aluminum coil is directly rolled on the cold rolling mill. The processing rate of each cold rolling pass is controlled at about 53%. The coil is rolled into a 1.4mm thick aluminum coil in 2 passes. The thickness tolerance of the cold-rolled product does not exceed ±1.5%. S5. Finished product annealing: Place the 1.4mm aluminum coil into the annealing furnace for finished product annealing. During finished product annealing, the temperature difference between different zones in the furnace is within ±3℃. After 2 hours of uniform heating to 220℃, hold under negative pressure for 4 hours, then after 2 hours of uniform heating to 420℃, hold under positive pressure for 23 hours, and then remove from the furnace when the furnace temperature drops to 170℃ and allow to cool naturally to room temperature. S6. Inspection and Packaging: Check that the thickness of the aluminum coil does not exceed the tolerance range, and that there are no folds or dents on the end face. The longitudinal tensile strength of the finished aluminum coil is 92MPa, the transverse tensile strength is 93MPa, the longitudinal elongation is ≥47%, and the transverse elongation is ≥46%. If it is qualified, it shall be packaged in accordance with the packaging requirements for aluminum coils for round sheets. Example 2

[0015] The specific steps of the low-carbon, short-process, high-throughput production method for expandable, deep-drawing aluminum coils for cookware are as follows: S1. Smelting: 58.2% recycled aluminum scrap and 41.8% molten electrolytic aluminum are remelted in a smelting furnace at 745℃ to prepare molten aluminum. An initial sample is taken for analysis. Based on the analysis results, iron, manganese, copper, titanium, aluminum-titanium alloy, and quick-dissolving silicon are added in one step to adjust the alloy composition to meet the requirements. The mass percentages of each component are: Si: 0.19%, Fe: 0.42%, Cu: 0.09%, Mn: 0.78%, Mg: 0.004%, Zn: 0.006%, Ti: 0.034%, with total impurities ≤ 0.03%, and the balance being aluminum. After the composition is adjusted to meet the requirements, further refining is carried out. During the refining and slag removal processes, an Hd2000 refining machine is used for argon refining for 29 minutes. When argon is introduced into the aluminum melt for refining, the tumbling height of the aluminum melt is ≤100mm. After refining, slag is removed, and the liquid surface must be mirror-like. The melt is allowed to stand for 38 minutes before being taken out of the furnace. After refining, slag removal, and standing, samples are taken from both sides of the furnace door to test the composition. The content deviation of each alloy is less than 0.01%. The temperature of the aluminum melt is controlled at 750℃ when the furnace is taken out. After the furnace is taken out, the aluminum melt flows smoothly into the guide channel. Four sets of aluminum-titanium-boron wires are added to the aluminum melt at a uniform speed. The aluminum melt enters the degassing box and plate filter box in sequence for online degassing and filtration before flowing into the front box. S2. Continuous Casting and Rolling: During continuous casting, molten aluminum in the forebox is injected into the casting cavity at a uniform speed through the casting nozzle. The molten aluminum in the casting cavity exits the plate as the steel strip rotates. The inner sides of the two steel strips are connected to the circulating cooling water. The cooling water temperature is controlled at 37℃ and the cooling water pressure is controlled at 0.58MPa. The heat in the molten aluminum is carried away by the cooling water through the steel strip. During continuous casting, the forebox temperature is maintained at 699℃, the casting speed is controlled at 7.7m / min, and the thickness of the cast slab is controlled at 19mm. The continuously cast slab enters the three-stand rolling mill through the looper table. During the slab rolling, emulsion is used for lubrication and cooling. The thickness at the entrance of the first stand of the three-stand rolling mill is 19mm, the thickness at the exit of the first stand of the three-stand rolling mill is 14mm, the thickness at the exit of the second stand of the three-stand rolling mill is 10mm, and the thickness at the exit of the third stand of the three-stand rolling mill is 7.5mm. The strip exiting the third stand of the three-stand rolling mill is coiled into aluminum coils by a coiler. S3. Homogenization Annealing: The aluminum coils rolled into coils need to undergo homogenization annealing first. During annealing, the 7.5mm thick billet is first placed in the high-level material rack in the annealing furnace to ensure suspended annealing. Then, the furnace temperature is raised to 580℃ for 4 hours and held for 25 hours. Then, the furnace temperature is lowered to 170℃ and the coils are taken out of the furnace. The annealed cold-rolled coils need to be air-cooled to 52℃ and transferred to subsequent production processes. S4. Cold rolling: After homogenization annealing, the 7.5mm thick aluminum coil is directly rolled on the cold rolling mill. The processing rate of each cold rolling pass is controlled at 47%. After two passes, it is rolled into an aluminum coil with a thickness of 2.1mm. The thickness tolerance of the cold-rolled product does not exceed ±1.5%. S5. Finished product annealing: Place the 2.1mm aluminum coil into the annealing furnace for finished product annealing. During finished product annealing, the temperature difference between different zones in the furnace is within ±3℃. After 2 hours, the temperature is raised to 220℃ and held under negative pressure for 4 hours. Then, after another 2 hours, the temperature is raised to 420℃ and held under positive pressure for 25 hours. Finally, when the furnace temperature is lowered to 170℃, the coil is removed from the furnace and allowed to cool naturally to room temperature. S6. Inspection and Packaging: Check that the thickness of the aluminum coil does not exceed the tolerance range, and that there are no folds or damage on the end face. The finished aluminum coil is tested to ensure that the longitudinal tensile strength reaches 96MPa, the transverse tensile strength reaches 95MPa, the longitudinal elongation is ≥51%, and the transverse elongation is ≥52%. It is then deemed qualified and packaged in accordance with the packaging requirements for aluminum coils for round sheets.

[0016] The parts of this invention not described in detail are prior art.

[0017] The embodiments selected herein for the purpose of disclosing the inventive objectives are currently considered suitable; however, it should be understood that the invention is intended to include all variations and modifications of the embodiments that fall within the scope of this concept and invention.

Claims

1. A low-carbon, short-process, high-throughput method for producing expandable, deep-drawn cookware aluminum coils, characterized by: Includes the following steps: S1. Smelting: 50%–60% recycled aluminum scrap and 40%–50% molten electrolytic aluminum are placed in a smelting furnace for remelting to prepare molten aluminum. The furnace temperature is 745–755℃. Stirring is performed, and an original sample is taken for testing. Based on the test results, iron, manganese, copper, titanium, aluminum-titanium alloy, and quick-dissolving silicon are added to adjust the alloy composition to meet the requirements. The mass percentages of each component are: Si: 0.1%–0.2%, Fe: 0.3%–0.5%, Cu: 0.05%–0.1%, Mn: 0.6~0.8%, Mg≤0.01%, Zn≤0.01%, Ti: 0.02%~0.04%, total impurity elements≤0.03%, balance is aluminum; after the composition is qualified, it is refined and slag is removed. After slag removal, it is allowed to stand for 30~40 minutes before the furnace is started. The temperature of the aluminum liquid is controlled at 740~750℃ when the furnace is started. After the furnace is started, the aluminum melt flows smoothly into the guide channel. Four sets of aluminum-titanium-boron wires are added to the aluminum melt at a uniform speed. The aluminum melt enters the degassing box and plate filter box in sequence for online degassing and filtration before flowing into the front box; S2. Continuous casting and rolling: During continuous casting, the molten aluminum in the front box is injected into the casting cavity at a uniform speed through the casting nozzle. The molten aluminum in the casting cavity exits the plate as the steel strip rotates. The continuously cast slab enters the three-stand rolling mill through the looper table. The thickness at the entrance of the first stand of the three-stand rolling mill is 19mm, the thickness at the exit of the first stand of the three-stand rolling mill is 13-14mm, the thickness at the exit of the second stand of the three-stand rolling mill is 9-10mm, and the thickness at the exit of the third stand of the three-stand rolling mill is 6.5-7.5mm. The plate exiting the third stand of the three-stand rolling mill is rolled into aluminum coils. S3. Homogenization annealing: The aluminum coil obtained in S2 is homogenized and annealed. During annealing, the billet is first placed in the annealing furnace. After 4 hours, the furnace temperature is raised to 580℃ at a constant rate and held for 20-25 hours. Then, the furnace temperature is lowered to 170℃ and the coil is taken out of the furnace. After annealing, the cold-rolled coil is cooled to below 60℃ and then transferred to the subsequent production process. S4. Cold rolling: The aluminum coils after homogenization annealing are directly rolled on the cold rolling mill. The processing rate of each cold rolling pass is controlled at 45-55%. After two passes, the aluminum coils are rolled to a thickness of 1.4-2.1 mm. S5. Finished product annealing: The aluminum coil obtained in step S4 is placed in an annealing furnace for finished product annealing. The temperature is raised to 220°C at a constant rate for 2 hours, and held under negative pressure for 4 hours. Then, the temperature is raised to 420°C at a constant rate for 2 hours, and held under positive pressure for 20-25 hours before being taken out of the furnace. Then, the furnace temperature is lowered to 170°C before being taken out of the furnace and allowed to cool naturally to room temperature. S6. Testing and Packaging: The tensile strength of the finished aluminum coil shall be 85MPa~100MPa, the elongation shall be ≥45%, and the difference between the longitudinal and transverse elongation shall be within 2%. The qualified finished products shall be packaged in accordance with the packaging requirements for aluminum coils for discs.

2. The method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils according to claim 1, characterized in that, In step S1, titanium agent and aluminum-titanium alloy are added to the aluminum melt simultaneously.

3. The method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils according to claim 1, characterized in that, In step S1, after the melt is refined, slag removed and allowed to stand, samples are taken from both sides of the furnace door to test the composition, with the content deviation of each alloy being less than 0.01%.

4. The method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils according to claim 1, characterized in that, In step S1, argon refining is performed using a refining machine for 20-30 minutes. When argon is introduced into the aluminum melt for refining, the tumbling height of the aluminum melt is ≤100mm.

5. The method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils according to claim 1, characterized in that, In step S2, the temperature of the front chamber is 685-705℃, the casting speed is 6.8-7.8m / min, and the thickness of the cast slab is 19mm.

6. The method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils according to claim 1, characterized in that, In step S3, during homogenization annealing, the aluminum billet coil needs to be placed on a high-level rack to ensure suspended annealing.

7. The method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils according to claim 1, characterized in that, In step S4, the thickness tolerance of the cold-rolled finished product shall not exceed ±1.5%.

8. The method for low-carbon, short-process, high-throughput production of expandable deep-drawing cookware aluminum coils according to claim 1, characterized in that, In step S5, the temperature difference between different zones in the furnace during finished product annealing is within ±3℃.