Method for low-carbon environment-friendly production of 3003ZNZR alloy blank by using composite brazing waste

Abstract

The invention belongs to the technical field of aluminum alloy production, and particularly discloses a method for producing 3003ZNZR alloy blank in a low-carbon and environment-friendly mode through composite brazing waste, composite brazing secondary aluminum waste is used for production in a large proportion, the rolling temperature of a cast plate is strictly controlled by optimizing alloy components and a three-pass continuous rolling process, and three-pass rolling production of a thinned blank is achieved; compared with a fusion casting and hot rolling production method, the production method has the advantages that the working procedures are greatly reduced, the production cost is much lower, the thickness of a finished blank is reduced, subsequent cold and foil rolling calendering processing is facilitated, and the production cost can be greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy production technology, and specifically discloses a method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste. Background Technology

[0002] Currently, domestic brazing materials are generally manufactured using two- or three-layer composite materials, such as 4343+3003+7072 and 4343+3003ZN+7072 three-layer composite materials. The 4343 alloy contains more than 7% Si by mass, the 3003 alloy contains more than 1% Mn by mass, the 3003ZN alloy contains more than 1% Mn and Zn by mass, and the 7072 alloy contains more than 1.0% Zn by mass. The production of such composite aluminum alloy strips inevitably generates composite alloy waste, which is rich in Si, Mn, and Zn. However, there are currently no conventional alloy materials that are permitted to contain large amounts of Si, Mn, and Zn simultaneously, so the disposal of such composite alloy waste is extremely difficult.

[0003] Based on the above, our company conducted extensive verification tests by rationally adjusting the alloy composition. We developed the Al-Mn modified alloy 3003ZNZR by adding Zn and Zr to the 3003 alloy. This alloy retains some Si to maintain brazing compatibility and facilitate brazing applications. Increasing the Zn content improves corrosion resistance and enhances high-temperature deformation resistance. Increasing the Zr content forms an Al3Zr dispersed phase, inhibiting high-temperature recrystallization and grain coarsening, stabilizing strength and grain size. Simultaneously, this alloy retains the good formability, weldability, and corrosion resistance of the 3003 alloy, making it more suitable for high-temperature applications. Through alloy composition improvement and optimization, the core advantages of this alloy are resistance to aging softening, suitability for high-temperature brazing, and good corrosion resistance and formability. After rolling, the billet is used to manufacture fins and heat dissipation strips for automotive radiators, condensers, and evaporators, as well as water-cooled plates for new energy vehicles and battery cooling components, based on its high-temperature brazing performance.

[0004] Currently, domestic production of 3003ZNZR alloy billets generally uses hot-rolled billets. For example, the manufacturing methods for 3003ZNZR aluminum alloy strips disclosed in Chinese patents CN102721316A, CN103103404B, and CN104342586B involve multiple processes such as melting and casting, milling, homogenization annealing, hot rolling, and cold rolling, resulting in long production cycles and high production costs. In addition, the milling process leads to high production losses and low yield. Chinese patent CN110496871 discloses a method for producing 3003ZNZR alloy billets using continuous casting and rolling, but this method requires aluminum ingots with an aluminum content of over 99.7%, 10-30% electrolytic aluminum liquid, and solid waste for production. It cannot utilize composite alloy waste rich in Si, Mn, and Zn elements. Furthermore, this method can only produce billets with a thickness of 2.5-4.5 mm, which is relatively thick and results in relatively high subsequent production costs. Summary of the Invention

[0005] To address the problems in the background art, this invention discloses a method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste. The method utilizes composite alloy waste for production, optimizes the three-pass rolling process, strictly controls the rolling temperature of the cast plate, and achieves three-pass rolling to produce thinner billets, thereby reducing subsequent processing costs and achieving the goal of low-carbon, environmentally friendly, and low-cost production throughout the entire process.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste specifically includes the following steps: S1. Smelting and Batching: A total of 110 parts by weight, in a weight ratio of (70-80):(20-30):(0-10), composite alloy waste, electrolytic aluminum liquid, and remelting aluminum ingots are added to a smelting furnace and heated to prepare an aluminum alloy melt. Samples are taken for testing. Based on the test results, quick-dissolving silicon, iron, copper, manganese, zinc ingots, titanium, and aluminum-zirconium alloy are added to the smelting furnace, stirred, and pre-refined. The mixture is stirred evenly and the alloy composition is adjusted to meet the requirements. The mass percentage of each component is as follows: Si: 0.5-0.8%, Fe: 0.2-0.3%, Cu: ≤0.12%, Mn: 1.0-1.08%, Zn: 1.3-1.6%, Zr: 0.08-0.12%, Mg: ≤0.03%, Ti: 0.01-0.04%, other individual impurities ≤0.03%, total ≤0.15%, and the balance is Al. S2. Melt purification treatment: After the aluminum melt composition is adjusted to meet the requirements, it is automatically refined and manually refined using a refining machine under electromagnetic stirring. After refining, it is allowed to stand for 10-20 minutes to remove slag. After removing slag, it is allowed to stand for 30-40 minutes before starting production. S3. Grain refiner addition: After the furnace is started, the aluminum alloy melt flows smoothly into the guide channel through the aluminum outlet. Four sets of aluminum-titanium-boron wires are added to the aluminum alloy melt at a constant speed in the opposite direction of the flow direction of the aluminum alloy melt. S4. Online degassing and filtration: The aluminum alloy melt with added aluminum-titanium-boron wire grain refiner flows through the degassing box and plate filter box in sequence through the guide channel for online degassing and filtration. The aluminum alloy melt after degassing and filtration flows into the front box through the vertical flow stabilizer. S5. Continuous casting: The temperature of the aluminum alloy melt in the front box is 670-680℃. The aluminum alloy melt flows into the casting cavity of the casting machine through the casting nozzle. The aluminum alloy melt solidifies in the casting cavity to form a billet. The billet exits the plate as the upper and lower steel strips rotate in the same direction. The casting speed is 6.0-6.5m / min. The billet thickness is 19mm. The exit temperature at the edge of the casting plate is 500-560℃. The exit temperature at the middle of the casting plate is 540-600℃. S6. Three-Stage Rolling: After passing through the pinch rolls of the casting machine, the billet enters the three-stage rolling mill for rolling. The billet exit thickness of the first stand of the three-stage rolling mill is 7.5-8.5 mm; the billet exit thickness of the second stand of the three-stage rolling mill is 3.0-4.0 mm; and the billet exit thickness of the third stand of the three-stage rolling mill is 1.5-2.0 mm. The material exiting the third stand of the three-stage rolling mill is directly coiled into a coil by a coiler to obtain 3003ZNZR alloy billet.

[0007] Furthermore, in the method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste, in step S1, the composite alloy waste is a mixture of 4343+3003+7072 alloys or a mixture of 4343+3003ZN+7072 alloys, and the mass percentage of 4343 alloy brazing layer waste in the alloy mixture is less than 11.25%.

[0008] Furthermore, in the method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste, in step S1, nitrogen gas is introduced into the refining machine for pre-refining, and the aluminum alloy melt at the stirring position is locally stirred to make the alloy composition more uniform and avoid segregation.

[0009] Furthermore, in the method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste, in step S2, the refining time for refining by a refining machine and manual refining is 30-40 minutes respectively. Argon is used as the refining gas for both refining by a refining machine and manual refining. During refining, the height of the aluminum liquid churning does not exceed 100 mm. During automatic refining, the refining rotor is fixed in a fixed position. During manual refining, the end of the refining tube is inserted into the aluminum liquid and swings in an N-shape in the aluminum liquid to ensure that all positions of the melt can be refined.

[0010] Furthermore, in the method for producing 3003ZNZR alloy billet in a low-carbon and environmentally friendly manner using composite brazing waste, in step S3, the grain refiner uses export-grade Al-5Ti-0.2B aluminum-titanium-boron wire, and the temperature of the aluminum alloy melt at the point where the aluminum-titanium-boron wire is added is 720±5℃.

[0011] Furthermore, in the method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste, in step S3, the fluctuation of the aluminum alloy melt surface after furnace start-up shall not exceed 5mm, so as to prevent the aluminum melt fluctuation from immersing the surface oxide film into the aluminum alloy melt and forming slag.

[0012] Furthermore, in the method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste, in step S4, the degassing box adopts a three-rotor degassing device. The main shaft and impeller of the degassing box rotor are both made of silicon nitride material. Argon gas is introduced into the degassing box rotor as the degassing working gas, and the argon gas purity is above 99.999%. Nitrogen gas is introduced into the degassing box to cover the surface of the aluminum alloy melt as a protective gas. Two plate filter plates are placed in series in the filter box, and the filter plate mesh number is not less than 50+60ppi.

[0013] Furthermore, in the method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste, in step S5, the upper and lower steel strips are heated using induction heaters, and the temperature of the steel strips is 120-140°C, in order to remove moisture from the surface of the steel strips and avoid moisture causing casting cavities.

[0014] Furthermore, in the method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste, in step S5, there is a pinch roller at the billet outlet, which transmits a torque to the billet in the opposite direction to the billet exiting the plate, and the torque is ≥4.5N·m.

[0015] Furthermore, in the method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste, in step S6, the temperature of the cast plate before entering the three-stand rolling mill is 480-530°C, and the final rolling temperature of the exit plate of the three-stand rolling mill is 200-230°C.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention discloses a method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste. By optimizing the alloy composition and controlling the total content of Fe and Mn elements to not exceed 1.4%, within this alloy composition range, iron and manganese coexist and are not prone to forming brittle iron-manganese-aluminum intermetallic compounds. The Al6(FeMn) undesirable phase is not generated, and the appearance of needle-like and plate-like brittle phases is avoided. This can effectively avoid significantly reducing the plasticity, toughness and processing performance of aluminum alloys and reduce the quality risk of billets. 2. The present invention discloses a method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste. By optimizing the alloy composition and controlling the total content of Fe and Mn elements to not exceed 1.4%, the solid solution Al6Mn phase formed by Mn as a strengthening element will also be reduced, the billet strength will be reduced, the hard and brittle intermetallic compounds will be reduced, the solid solution strengthening effect will be weakened, the deformation resistance will be reduced and the plasticity will be improved. Subsequent rolling with a large reduction can be carried out, which is convenient to achieve the production of billets with a thickness of 1.5-2.0mm. The reduction of the billet thickness means a reduction in subsequent production costs. 3. The present invention discloses a method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste. It uses a large proportion of composite brazing recycled aluminum waste for production. By improving and optimizing the in-furnace and online melt refining process, and using a plate filter box with dual-stage 50+60ppi filter plates in series for filtration, the filtration effect is guaranteed, the quality of the billet melt is stabilized, and quality problems are prevented in the subsequent production of aluminum foil products. 4. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste disclosed in this invention has a high production speed, with an output of over 32 tons per hour. A single tilting furnace can produce 110 tons of melt in 3.5 hours. The aluminum alloy melt has a short residence time and holding time in the furnace, resulting in low natural gas consumption; the natural gas consumption per ton of billet produced does not exceed 50 m³. 3 Compared to the traditional casting and rolling method, which requires 65m³ of billet per ton to produce, 3 Natural gas consumption has decreased significantly; 5. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste disclosed in this invention has the following advantages: the billet temperature reaches above 480°C when it enters the mill stand for rolling, and the exit temperature of the three-roll mill is above 200°C. Both of these temperatures are above the recrystallization temperature, resulting in low material deformation resistance and low power consumption during the production process. The power consumption per ton is less than 180 kWh, which is significantly lower than the 220 kWh per ton required for billet production by the traditional casting and rolling method. 6. The present invention discloses a method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste. The 19mm cast billet can be rolled into 1.5-2.0mm 3003ZNZR alloy billets through three consecutive rolling processes. Compared with the casting + hot rolling production method, this method significantly reduces the number of processes and the production cost is much lower. In addition, the reduced thickness of the finished billet facilitates subsequent cold and foil rolling processes, which can significantly reduce production costs. Detailed Implementation

[0017] 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

[0018] The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste is as follows: S1. Smelting Batching: 72.26 tons of composite waste, 28.35 tons of electrolytic aluminum liquid, and 9.39 tons of remelting aluminum ingots are added to the smelting furnace and heated to prepare aluminum alloy melt. The composite waste is a mixture of 4343+3003+7072 alloy or a mixture of 4343+3003ZN+7072 alloy, and the 4343 alloy in the composite waste does not exceed 8 tons. Sampling and testing are performed. Based on the test results, quick-dissolving silicon, iron, copper, manganese, zinc ingots, titanium, and aluminum-zirconium alloy are added to the smelting furnace, and the electromagnetic induction is turned on. The stirring and HD2000 refining mill work together to achieve stirring and pre-refining, ensuring uniform mixing of all alloying elements and adjusting the alloy composition to meet the required standards. The mass percentages of each component are as follows: Si: 0.58%, Fe: 0.23%, Cu: 0.05%, Mn: 1.01%, Zn: 1.42%, Zr: 0.085%, Mg: 0.01%, Ti: 0.016%, with other individual impurities ≤0.03% and total impurities ≤0.15%, and the balance being Al. S2. Melt Purification Treatment: After the aluminum melt composition is adjusted to meet the requirements, turn on the electromagnetic stirrer and simultaneously use the HD2000 refining machine for automatic refining and manual refining. The HD2000 refining machine uses argon as the refining gas for automatic refining, and uses argon as a carrier to blow granular refining agent into the aluminum alloy melt for refining. During automatic refining, the refining rotor is fixed in a fixed position. During manual refining, the end of the refining tube needs to be inserted into the aluminum liquid and swing in an N-shape in the aluminum liquid to ensure that all parts of the melt are refined. The refining time for both machine refining and manual refining is 37 minutes. After refining, let it stand for 18 minutes and then remove the slag. After removing the slag, the surface of the aluminum alloy melt is mirror-like, and there is no aluminum slag with an area greater than 50×50mm floating on the surface of the melt. After removing the slag, let it stand for 35 minutes and then start production. S3. Grain refiner addition: After the furnace is started, the aluminum alloy melt flows smoothly into the guide channel through the aluminum outlet. The surface of the aluminum alloy melt fluctuates by 2mm after the furnace is started to prevent the surface oxide film from being immersed into the aluminum alloy melt and forming slag. Four sets of aluminum-titanium-boron wires are added to the aluminum alloy melt at a uniform speed using a titanium wire machine. The aluminum-titanium-boron wires must be added to the melt in the opposite direction to the flow direction of the aluminum alloy melt. The aluminum-titanium-boron wires are not allowed to be added close to the wall of the channel. The temperature of the aluminum alloy melt at the point where the aluminum-titanium-boron wires are added is 718℃. S4. Online Degassing and Filtration: The aluminum alloy melt with added aluminum-titanium-boron wire grain refiner flows through the guide channel sequentially through the degassing box and the plate filter box for online degassing and filtration. The degassing box adopts a three-rotor degassing device. The main shaft and impeller of the degassing box rotor must be made of silicon nitride material. Argon gas is introduced into the degassing box rotor as the working gas for degassing. The purity of argon gas is above 99.999%. Nitrogen gas is introduced into the degassing box to cover the surface of the aluminum alloy melt as a protective gas. Two plate filter plates are placed in series in the filter box. The filter plate mesh number is not less than 50+60ppi. The aluminum alloy melt after degassing and filtration flows into the front box through the vertical flow stabilizer. S5, Continuous Casting: The temperature of the aluminum alloy melt in the front box is 671℃. The aluminum alloy melt flows into the casting cavity of the casting machine through the casting nozzle. The aluminum alloy melt solidifies in the casting cavity to form a billet. The billet exits the plate with the upper and lower steel strips rotating in the same direction. The casting speed is 6.1m / min, the billet thickness is 19mm, the edge exit temperature of the billet is 520℃, and the middle exit temperature of the billet is 545℃. The upper and lower steel strips are heated by induction heaters to remove moisture from the surface of the steel strips. The surface temperatures of the upper and lower steel strips are measured to be 128℃ and 127℃, respectively. The torque transmitted by the billet pinch rollers to the billet in the opposite direction to the billet exiting the plate is 5.2N·m. S6. Three-Stage Rolling: The slab temperature is 491℃ before the slab enters the mill stand. After passing through the pinch rolls of the casting machine, the slab enters the three-stage rolling mill for rolling. The slab exit thickness of the first stand of the three-stage rolling mill is 7.6mm; the slab exit thickness of the second stand of the three-stage rolling mill is 3.2mm; the slab exit thickness of the third stand of the three-stage rolling mill is 1.5mm. The final rolling temperature of the slab at the exit of the three-stage rolling mill is 211℃. The material exiting the third stand of the three-stage rolling mill is directly coiled into a coil by the coiler to obtain 3003ZNZR alloy slab. Example 2

[0019] The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste is as follows: S1. Smelting Batching: 79.81 tons of composite waste, 23.41 tons of electrolytic aluminum liquid, and 6.78 tons of remelting aluminum ingots are added to the smelting furnace and heated to prepare aluminum alloy melt. The composite waste is a mixture of 4343+3003+7072 alloy or a mixture of 4343+3003ZN+7072 alloy, and the 4343 alloy in the composite waste does not exceed 8.9 tons. Sampling and testing are conducted. Based on the test results, quick-dissolving silicon, iron, copper, manganese, zinc ingots, titanium, and aluminum-zirconium alloy are added to the smelting furnace. Turn on the electromagnetic stirrer and HD2000. The combined action of the two achieves stirring and pre-refining, ensuring that all alloying elements are stirred evenly and the alloy composition is adjusted to meet the requirements. The mass percentage of each component is as follows: Si: 0.76%, Fe: 0.28%, Cu: 0.11%, Mn: 1.07%, Zn: 1.58%, Zr: 0.11%, Mg: 0.02%, Ti: 0.038%, other individual impurities ≤0.03%, total ≤0.15%, balance Al; S2. Melt Purification Treatment: After the aluminum melt composition is adjusted to meet the requirements, the electromagnetic stirrer is turned on, and the HD2000 refining machine is used for automatic refining and manual refining at the same time. The HD2000 refining machine uses argon as the refining gas for automatic refining, and uses argon as a carrier to blow the granular refining agent into the aluminum alloy melt for refining. During the automatic refining machine refining, the refining rotor is fixed in a fixed position. During the manual refining, the end of the refining tube needs to be inserted into the aluminum liquid and swing in an N-shaped motion in the aluminum liquid to ensure that all parts of the melt are refined. The refining time for both the refining machine and manual refining is 39 minutes. After refining, it is allowed to stand for 14 minutes and then the slag is removed. After removing the slag, the surface of the aluminum alloy melt is mirror-like, and there is no aluminum slag with an area greater than 50×50mm floating on the surface of the melt. After removing the slag, it is allowed to stand for 33 minutes before starting production. S3. Grain refiner addition: After the furnace is started, the aluminum alloy melt flows smoothly into the guide channel through the aluminum outlet. The surface of the aluminum alloy melt fluctuates by 1 mm after the furnace is started to prevent the surface oxide film from being immersed into the aluminum alloy melt and forming slag. Four sets of aluminum-titanium-boron wires are added to the aluminum alloy melt at a uniform speed using a titanium wire machine. The aluminum-titanium-boron wires are added to the melt in the opposite direction of the flow of the aluminum alloy melt. The aluminum-titanium-boron wires are not allowed to be added close to the wall of the channel. The temperature of the aluminum alloy melt at the point where the aluminum-titanium-boron wires are added is 723℃. S4. Online Degassing and Filtration: The aluminum alloy melt with added aluminum-titanium-boron wire grain refiner flows through the guide channel sequentially through the degassing box and the plate filter box for online degassing and filtration. The degassing box adopts a three-rotor degassing device. The main shaft and impeller of the degassing box rotor must be made of silicon nitride material. Argon gas is introduced into the degassing box rotor as the working gas for degassing. The purity of argon gas is above 99.999%. Nitrogen gas is introduced into the degassing box to cover the surface of the aluminum alloy melt as a protective gas. Two plate filter plates are placed in series in the filter box. The filter plate mesh number is not less than 50+60ppi. The aluminum alloy melt after degassing and filtration flows into the front box through the vertical flow stabilizer. S5, Continuous Casting: The temperature of the aluminum alloy melt in the front box is 676℃. The aluminum alloy melt flows into the casting cavity of the casting machine through the casting nozzle. The aluminum alloy melt solidifies in the casting cavity to form a billet. The billet exits the plate with the upper and lower steel strips rotating in the same direction. The casting speed is 6.4m / min, the billet thickness is 19mm, the edge exit temperature of the billet is 545℃, and the middle exit temperature of the billet is 585℃. The upper and lower steel strips are heated by induction heaters to remove moisture from the surface of the steel strips. The surface temperatures of the upper and lower steel strips are measured to be 131℃ and 136℃, respectively. The torque transmitted by the billet pinch rollers to the billet in the opposite direction to the billet exiting the plate is 6.7N·m. S6. Three-Stage Rolling: The slab temperature is 512℃ before the slab enters the mill stand. After passing through the pinch rolls of the casting machine, the slab enters the three-stage rolling mill for rolling. The slab exit thickness of the first stand of the three-stage rolling mill is 8.1mm; the slab exit thickness of the second stand of the three-stage rolling mill is 3.8mm; the slab exit thickness of the third stand of the three-stage rolling mill is 2.0mm. The final rolling temperature of the slab at the exit of the three-stage rolling mill is 223℃. The material exiting the third stand of the three-stage rolling mill is directly coiled into a coil by the coiler to obtain 3003ZNZR alloy slab. Example 3

[0020] The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste is as follows: S1. Smelting and Batching: 80 tons of composite waste and 30 tons of electrolytic aluminum liquid are added to the smelting furnace and heated to prepare aluminum alloy melt. The composite waste is a mixture of 4343+3003+7072 alloy or a mixture of 4343+3003ZN+7072 alloy, and the amount of 4343 alloy in the composite waste does not exceed 9 tons. Samples are taken for testing. Based on the test results, quick-dissolving silicon, iron, copper, manganese, zinc ingots, titanium, and aluminum-zirconium alloy are added to the smelting furnace. The electromagnetic stirrer and HD2 are turned on. The 000 refining mill, through the combined action of both, achieves stirring and pre-refining, ensuring uniform stirring of all alloying elements and adjusting the alloy composition to meet the required standards. The mass percentages of each component are as follows: Si: 0.63%, Fe: 0.21%, Cu: 0.06%, Mn: 1.05%, Zn: 1.51%, Zr: 0.09%, Mg: 0.02%, Ti: 0.023%, other individual impurities ≤0.03%, total ≤0.15%, with the balance being Al. S2. Melt Purification Treatment: After the aluminum melt composition is adjusted to meet the requirements, turn on the electromagnetic stirrer and simultaneously use the HD2000 refining machine for automatic refining and manual refining. The HD2000 refining machine uses argon as the refining gas for automatic refining, and uses argon as a carrier to blow granular refining agent into the aluminum alloy melt for refining. During automatic refining, the refining rotor is fixed in a fixed position. During manual refining, the end of the refining tube needs to be inserted into the aluminum liquid and swing in an N-shape in the aluminum liquid to ensure that all parts of the melt are refined. The refining time for both machine refining and manual refining is 40 minutes. After refining, let it stand for 16 minutes and then remove the slag. After removing the slag, the surface of the aluminum alloy melt is mirror-like, and there is no aluminum slag with an area larger than 50×50mm floating on the surface of the melt. After removing the slag, let it stand for 37 minutes and then start production. S3. Grain refiner addition: After the furnace is started, the aluminum alloy melt flows smoothly into the guide channel through the aluminum outlet. The surface of the aluminum alloy melt fluctuates by 1 mm after the furnace is started to prevent the surface oxide film from being immersed into the aluminum alloy melt and forming slag. Four sets of aluminum-titanium-boron wires are added to the aluminum alloy melt at a uniform speed using a titanium wire machine. The aluminum-titanium-boron wires are added to the melt in the opposite direction of the flow of the aluminum alloy melt. The aluminum-titanium-boron wires are not allowed to be added close to the wall of the channel. The temperature of the aluminum alloy melt at the point where the aluminum-titanium-boron wires are added is 725℃. S4. Online Degassing and Filtration: The aluminum alloy melt with added aluminum-titanium-boron wire grain refiner flows through the guide channel sequentially through the degassing box and the plate filter box for online degassing and filtration. The degassing box adopts a three-rotor degassing device. The main shaft and impeller of the degassing box rotor must be made of silicon nitride material. Argon gas is introduced into the degassing box rotor as the working gas for degassing. The purity of argon gas is above 99.999%. Nitrogen gas is introduced into the degassing box to cover the surface of the aluminum alloy melt as a protective gas. Two plate filter plates are placed in series in the filter box. The filter plate mesh number is not less than 50+60ppi. The aluminum alloy melt after degassing and filtration flows into the front box through the vertical flow stabilizer. S5, Continuous Casting: The temperature of the aluminum alloy melt in the front box is 675℃. The aluminum alloy melt flows into the casting cavity of the casting machine through the casting nozzle. The aluminum alloy melt solidifies in the casting cavity to form a billet. The billet exits the plate with the upper and lower steel strips rotating in the same direction. The casting speed is 6.3m / min, the billet thickness is 19mm, the edge exit temperature of the billet is 560℃, and the middle exit temperature of the billet is 600℃. The upper and lower steel strips are heated by induction heaters to remove moisture from the surface of the steel strips. The surface temperatures of the upper and lower steel strips are measured to be 132℃ and 135℃, respectively. The torque transmitted by the billet pinch rollers to the billet in the opposite direction to the billet exiting the plate is 6.5N·m. S6. Three-Stage Rolling: The slab temperature is 521℃ before the slab enters the mill stand. After passing through the pinch rolls of the casting machine, the slab enters the three-stage rolling mill for rolling. The slab exit thickness of the first stand of the three-stage rolling mill is 8.5mm; the slab exit thickness of the second stand of the three-stage rolling mill is 4.0mm; the slab exit thickness of the third stand of the three-stage rolling mill is 2.0mm. The final rolling temperature of the slab at the exit of the three-stage rolling mill is 226℃. The material exiting the three stands of the three-stage rolling mill is directly coiled into coils by the coiler to obtain 3003ZNZR alloy slab.

[0021] The parts of this invention not described in detail are prior art.

[0022] 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 method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste, characterized in that: Specifically, the following steps are included: S1. Smelting and Batching: A total of 110 parts by weight, in a weight ratio of (70-80):(20-30):(0-10), composite alloy waste, electrolytic aluminum liquid, and remelting aluminum ingots are added to a smelting furnace and heated to prepare an aluminum alloy melt. Samples are taken for testing. Based on the test results, quick-dissolving silicon, iron, copper, manganese, zinc ingots, titanium, and aluminum-zirconium alloy are added to the smelting furnace, stirred, and pre-refined. The mixture is stirred evenly and the alloy composition is adjusted to meet the requirements. The mass percentage of each component is as follows: Si: 0.5-0.8%, Fe: 0.2-0.3%, Cu: ≤0.12%, Mn: 1.0-1.08%, Zn: 1.3-1.6%, Zr: 0.08-0.12%, Mg: ≤0.03%, Ti: 0.01-0.04%, other individual impurities ≤0.03%, total ≤0.15%, and the balance is Al. S2. Melt purification treatment: After the aluminum melt composition is adjusted to meet the requirements, it is automatically refined and manually refined using a refining machine under electromagnetic stirring. After refining, it is allowed to stand for 10-20 minutes to remove slag. After removing slag, it is allowed to stand for 30-40 minutes before starting production. S3. Grain refiner addition: After the furnace is started, the aluminum alloy melt flows smoothly into the guide channel through the aluminum outlet. Four sets of aluminum-titanium-boron wires are added to the aluminum alloy melt at a constant speed in the opposite direction of the flow direction of the aluminum alloy melt. S4. Online degassing and filtration: The aluminum alloy melt with added aluminum-titanium-boron wire grain refiner flows through the degassing box and plate filter box in sequence through the guide channel for online degassing and filtration. The aluminum alloy melt after degassing and filtration flows into the front box through the vertical flow stabilizer. S5. Continuous casting: The temperature of the aluminum alloy melt in the front box is controlled at 670-680℃. The aluminum alloy melt flows into the casting cavity of the casting machine through the casting nozzle. The aluminum alloy melt solidifies in the casting cavity to form a billet. The billet exits the plate as the upper and lower steel strips rotate in the same direction. The casting speed is 6.0-6.5m / min, the billet thickness is 19mm, the edge exit temperature of the casting plate is 500-560℃, and the middle exit temperature of the casting plate is 540-600℃. S6. Three-Stage Rolling: After passing through the pinch rolls of the casting machine, the billet enters the three-stage rolling mill for rolling. The billet exit thickness of the first stand of the three-stage rolling mill is 7.5-8.5 mm; the billet exit thickness of the second stand of the three-stage rolling mill is 3.0-4.0 mm; and the billet exit thickness of the third stand of the three-stage rolling mill is 1.5-2.0 mm. The material exiting the third stand of the three-stage rolling mill is directly coiled into a coil by a coiler to obtain 3003ZNZR alloy billet.

2. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste according to claim 1, characterized in that, In step S1, the composite alloy scrap is a mixture of 4343+3003+7072 alloy or a mixture of 4343+3003ZN+7072 alloy, and the mass percentage of 4343 alloy brazing layer scrap in the alloy mixture is less than 11.25%.

3. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste according to claim 1, characterized in that, In step S1, nitrogen gas is introduced into the refining machine for pre-refining, and the aluminum alloy melt at the stirring position is locally stirred to make the alloy composition more uniform and avoid segregation.

4. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste according to claim 1, characterized in that, In step S2, the refining time for refining by the refining machine and manual refining is 30-40 minutes. Argon is used as the refining gas for both refining by the refining machine and manual refining. During refining, the tumbling of the aluminum liquid does not exceed 100 mm. When refining by the automatic refining machine, the refining rotor is fixed in a fixed position. When refining by manual refining, the end of the refining tube is inserted into the aluminum liquid and swings in an N-shape in the aluminum liquid to ensure that all parts of the melt can be refined.

5. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste according to claim 1, characterized in that, In step S3, the grain refiner uses export-grade Al-5Ti-0.2B aluminum-titanium-boron wire, and the temperature of the aluminum alloy melt at the point where the aluminum-titanium-boron wire is added is 720±5℃.

6. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste according to claim 1, characterized in that, In step S3, the fluctuation of the aluminum alloy melt surface after the furnace is started shall not exceed 5mm, so as to prevent the aluminum melt fluctuation from immersing the surface oxide film into the aluminum alloy melt and forming slag.

7. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste according to claim 1, characterized in that, In step S4, the degassing box adopts a three-rotor degassing device. The main shaft and impeller of the degassing box rotor are both made of silicon nitride material. Argon gas is introduced into the degassing box rotor as the working gas for degassing. Nitrogen gas is introduced into the degassing box to cover the surface of the aluminum alloy melt as a protective gas. Two plate filter plates are placed in series in the filter box. The filter plate has a filtration mesh of not less than 50+60ppi.

8. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste according to claim 1, characterized in that, In step S5, the upper and lower steel strips are heated using induction heaters. The temperature of the steel strips is 120-140°C to remove moisture from the surface of the steel strips and prevent moisture from causing casting cavities.

9. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste according to claim 1, characterized in that, In step S5, there is a pinch roller at the billet outlet. The pinch roller transmits a torque to the billet in the opposite direction to the billet exiting the plate. The torque is ≥4.5 N·m.

10. The method for producing 3003ZNZR alloy billets in a low-carbon and environmentally friendly manner using composite brazing waste according to claim 1, characterized in that, In step S6, the temperature of the cast plate before entering the three-stand rolling mill is 480-530℃, and the final rolling temperature of the rolled plate at the exit of the three-stand rolling mill is 200-230℃.