Method for producing non-national-standard aluminum alloy single-layer brazing blank with low carbon and high efficiency

Abstract

The invention relates to the technical field of aluminum alloy production, in particular to a low-carbon and efficient method for producing a non-national-standard aluminum alloy single-layer brazing blank, due to the fact that the content of Mn, Si and Zn alloy components is high, secondary aluminum waste can be used in a large proportion, the low-carbon and environment-friendly purposes are achieved, the non-national-standard aluminum alloy single-layer brazing blank is produced through a continuous casting and rolling process, and the production cost is low. The inlet rolling temperature of each rack of the triple rolling mill is high, and the finish rolling temperature is also high, so that the internal dislocation of a material can be eliminated by a self-tempering effect, the edge cracking condition of the blank is improved, meanwhile, the internal dislocation of the material is less, the stress is small, the large-processing-rate rolling in the subsequent process can be facilitated, the rolling pass is reduced, the production of the blank with the width of 1650mm can be realized, and the production cost is reduced. The downstream production efficiency is greatly improved, and the production efficiency of more than 30t per hour is realized.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy production technology, specifically disclosing a low-carbon and high-efficiency method for producing non-standard aluminum alloy single-layer brazing blanks. Background Technology

[0002] Brazing filler metal is a core component of automotive radiators. Its primary function is to firmly weld together the radiator's multi-layered metal structure and ensure efficient heat transfer to the outside environment. Through high-temperature melting, the brazing filler metal welds the dispersed heat pipes, main and side plates, and other components into a sealed whole. This sealed unit must withstand coolant pressure, resist vibrations and impacts from vehicle operation, and ensure the radiator remains leak-proof and doesn't fall apart. The solder joints / welds formed by the brazing filler metal must have good thermal conductivity to quickly transfer heat from the coolant inside the heat pipes to the heat sink fins, ensuring stable heat dissipation efficiency.

[0003] Currently, multi-layer composite materials are commonly used to manufacture brazing alloys. However, the manufacturing process for multi-layer brazing alloys is complex and costly. Furthermore, the different alloy compositions in each layer of the composite material result in highly mixed alloy compositions in the production waste, which contains various high levels of alloying elements that are difficult to utilize. Therefore, the industry has begun to experiment with single-layer brazing alloys in scenarios where heat dissipation requirements are not extreme. Since single-layer brazing alloys eliminate the need for complex layering and step-by-step welding of multi-layer alloys, they reduce solder consumption and production steps, lowering costs and gaining increasing market favor.

[0004] Currently, single-layer brazing blanks are all produced using cast-rolled blanks, resulting in unstable blank quality, large cracks and edge splits, and low production efficiency. Chinese patent CN105229182B discloses a method for manufacturing single-layer aluminum alloy materials with heating bonding function, including a casting process using twin-roll continuous casting and rolling, a cold rolling process, and an annealing process for the rolled plate during the cold rolling process. Aluminum coils produced by this method are highly susceptible to edge cracks and peeling during cold rolling. When large cracks appear at the edges of the coil, the coil is at high risk of breakage during cold rolling. Chinese patent CN113174548B discloses a single-layer aluminum alloy fin material for brazing and its manufacturing method. In its production scheme, the twin-roll continuous casting and rolling speed is only 550–700 mm / min, with an hourly output of less than 1 ton, resulting in low efficiency. There is an urgent need to develop a high-efficiency production method for single-layer brazing blanks, while simultaneously improving blank quality, reducing edge and crack problems, facilitating subsequent rolling processes, and further reducing overall production costs. Summary of the Invention

[0005] To address the problems in the background art, this invention discloses a low-carbon and high-efficiency method for producing non-standard aluminum alloy single-layer brazing blanks. It utilizes a large proportion of recycled aluminum waste to produce the required blanks efficiently and with high quality, achieving the goals of low carbon, environmental protection, and high efficiency.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A low-carbon and high-efficiency method for producing non-standard aluminum alloy single-layer brazing blanks specifically includes the following steps: S1. Smelting and Batching: Electrolytic aluminum liquid (5-15% by mass) and recycled aluminum waste (85-95% by mass) are placed into a smelting furnace to prepare aluminum melt. Samples are taken for testing. Based on the test results, quick-dissolving silicon, iron, copper, manganese, titanium, and zinc ingots are added to the smelting furnace. The mixture is electromagnetically stirred for 20-30 minutes to ensure that the alloy composition is adjusted to meet the requirements. The mass percentage of each component is as follows: Si: 2.5-3.5%, Fe: ≤0.5%, Cu: ≤0.05%, Mn: 1.1-1.5%, Mg: ≤0.02%, Zn: 1.7-2.1%, Ti: 0.045-0.055%, other individual impurities ≤0.03%, total ≤0.15%, with the balance being Al. S2. Melt purification treatment: Under electromagnetic stirring, the qualified aluminum melt is refined by a combination of refining machine and manual refining. After refining, the slag is removed and the furnace is opened after standing for 30 to 50 minutes. S3. Grain refiner addition: After the furnace is started, the aluminum melt flows smoothly into the guide channel, and aluminum titanium boron wire is added to the aluminum melt at a uniform speed. S4. Online degassing and filtration: The aluminum melt flows into the degassing box and the plate filter box in sequence for online degassing and filtration. After degassing and filtration, the aluminum melt flows into the front box through the vertical flow stabilizer. S5, Continuous casting: The temperature of the molten aluminum in the front box is 690℃~700℃. The molten aluminum flows into the casting chamber of the casting machine through the casting nozzle and solidifies in the casting chamber 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 7.0~7.5m / 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 540~580℃. S6. Three-Stage Rolling: After passing through the mill pinch rolls, 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 8.0-9.0 mm; the billet exit thickness of the second stand of the three-stage rolling mill is 3.7-4.2 mm; and the billet exit thickness of the third stand of the three-stage rolling mill is 1.7-2.0 mm. The material exiting the third stand of the three-stage rolling mill is directly coiled into a coil to obtain aluminum alloy single-layer brazed billet.

[0007] Furthermore, in the method for producing non-standard aluminum alloy single-layer brazing blanks with low carbon and high efficiency, in step S2, the refining gas is argon, and argon is used as a carrier to blow the refining agent into the aluminum melt. The amount of refining agent is 2-3 kg / ton of aluminum melt, the argon pressure is 0.5±0.1 MPa, and the refining is carried out for 50-60 minutes using a refining machine. The rotor speed of the refining machine is 500±50 rpm.

[0008] Furthermore, in the method for producing non-standard aluminum alloy single-layer brazing blanks with low carbon and high efficiency, in step S3, two sets of aluminum-titanium-boron wires are added to the aluminum melt at a speed of 3.0±1m / min at the inlet of the degassing box, with an interval of 20-30cm between the addition points of the aluminum-titanium-boron wires and a temperature of 710-730℃ at the addition points of the aluminum-titanium-boron wires.

[0009] Furthermore, in the method for producing non-standard aluminum alloy single-layer brazing blanks with low carbon and high efficiency, in step S4, argon gas is introduced into the degassing box for online refining, the argon gas pressure is 0.5±0.05MPa, the speed of the three sets of rotors is set to 500±10 rpm, and slag is removed from the degassing box at least once per hour.

[0010] Furthermore, in the method for producing non-standard aluminum alloy single-layer brazing blanks with low carbon emissions and high efficiency, in step S5, the casting nozzle adopts a casting nozzle with a mixing zone.

[0011] Furthermore, in the method for producing non-standard aluminum alloy single-layer brazed billets with low carbon and high efficiency, in step S6, before the cast plate enters the three-stand rolling mill, it must be rinsed and cooled with emulsion, and the emulsion rinsing volume is 1000-1500L / min.

[0012] Furthermore, in the method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing billets, in step S6, the mass percentage of the sprayed emulsion on the first stand, second stand, and third stand of the three-stand rolling mill is 3.5 ± 0.1%.

[0013] Furthermore, in the method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing billets, in step S6, the inlet rolling temperature of the first stand of the three-stand rolling mill is 460-540℃; the inlet rolling temperature of the second stand of the three-stand rolling mill is 340-410℃; the inlet rolling temperature of the third stand of the three-stand rolling mill is 260-340℃; the final rolling temperature of the aluminum coil after three-stand rolling is 190℃-220℃; the edge crack of the aluminum coil after three-stand rolling is less than 1mm; and the number of edge cracks per meter length is less than 10.

[0014] Furthermore, in the method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazed billets, in step S6, during continuous rolling, the bending roll coefficients of the first stand, the second stand, and the third stand of the three-stand rolling mill are 80%, 60%, and 40%, respectively.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) Using this scheme to produce non-standard aluminum alloy single-layer brazed billets, it is possible to produce billets with a width of 1650mm, which greatly improves the downstream production efficiency. Relying on the good cooling effect of the Hazlet casting machine, it can produce at high speed and achieve a production efficiency of more than 30t per hour. (2) Using this scheme to produce non-standard aluminum alloy single-layer brazed billets, since the entry rolling temperature of each stand of the three-stand rolling mill is high and the final rolling temperature is also high, the self-tempering effect can be achieved to eliminate internal dislocations in the material and improve the edge cracking condition of the billet. At the same time, since there are few internal dislocations and low stress in the material, it is easy for subsequent processes to roll with a high processing rate, and the absolute reduction per pass is greater, reducing the number of rolling passes and further reducing production costs. (3) Using this scheme to produce non-standard aluminum alloy single-layer brazing billets, since the content of Mn, Si and Zn alloy components is high, recycled aluminum waste can be used in large proportion to achieve the goal of low carbon and environmental protection. The use of recycled aluminum waste in large proportion will inevitably affect the cleanliness and quality of aluminum melt. After optimizing the refining method by using a mixed refining operation of refining machine + manual refining, the purity of melt quality can be guaranteed. The billets produced by this scheme can achieve the rolling of aluminum foil with a minimum thickness of 0.04mm without breaking. Detailed Implementation

[0016] 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

[0017] A method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks, comprising the following specific steps: S1. Smelting and Batching: Electrolytic aluminum liquid with a mass percentage of 6.21% and recycled aluminum scrap with a mass percentage of 93.79% are placed into the smelting furnace to prepare aluminum melt. Mechanical stirring is performed for 10-20 minutes using a slag remover. Samples are taken for testing. Based on the test results, quick-dissolving silicon, iron, copper, manganese, titanium, and zinc ingots are added to the smelting furnace. Electromagnetic stirring is turned on for 25 minutes to ensure that the alloy composition is adjusted to meet the requirements. The mass percentages of each component are as follows: Si: 2.61%, Fe: 0.35%, Cu: 0.03%, Mn: 1.25%, Mg: 0.01%, Zn: 1.81%, Ti: 0.046%, other individual impurities ≤0.03%, total ≤0.15%, and the balance is Al. S2. Melt Purification Treatment: The qualified aluminum melt begins refining, using a combination of an HD2000 refining machine and manual refining. The HD2000 refining machine uses argon as the refining gas, maintaining an argon pressure of 0.42 MPa and a rotor speed of 476 rpm. Refining on the HD2000 machine takes 50-60 minutes to ensure effective melt refining and to achieve localized mixing and prevent segregation. Manual refining uses argon as a carrier to blow environmentally friendly refining agents into the aluminum melt. The refining agent is used at a rate of 2.2 kg per ton of molten aluminum. Manual refining should be carried out simultaneously on both sides of the furnace door, and a Z-shaped refining process should be adopted to ensure that the refining areas overlap. The electromagnetic stirrer should be turned on throughout the refining process. After refining, the molten aluminum should be slag removed using a slag removal vehicle. The surface of the molten aluminum after slag removal should be mirror-like, and there should be no slag with an area exceeding 50 mm × 50 mm. After slag removal, the molten aluminum should be allowed to stand for 32 minutes. After refining, slag removal and standing, samples should be taken from both sides of the furnace door to test the composition. The content deviation of each alloy should be less than 0.02%. The furnace should then be started. S3. Grain refiner addition: After the furnace is started, the aluminum melt flows smoothly into the guide flow channel. Two sets of aluminum-titanium-boron wires are added to the melt at a speed of 2.9 m / min. The aluminum-titanium-boron wires are added at the inlet of the degassing box, with an interval of 24 cm between the aluminum-titanium-boron wires. The temperature of the aluminum-titanium-boron wires is controlled at 712℃. S4. Online degassing and filtration: The aluminum melt flows into the degassing box, where argon gas is introduced for online refining. The argon gas pressure is 0.48MPa, and the speed of the three rotors is set to 495 rpm. After the aluminum melt comes out of the degassing box, it enters the plate filter box. Two ceramic filter plates of 30+40ppi are placed in series in the plate filter box. The aluminum melt after degassing and filtration flows into the front box through the vertical flow stabilizer. S5, Continuous Casting: The temperature of the molten aluminum in the front box is maintained at 692℃. The molten aluminum flows into the casting cavity of the casting machine through the nozzle with a mixing zone. The heat of the molten aluminum is carried away by the circulating cooling water inside the steel strip. The molten aluminum 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 controlled at 7.1m / min, the billet thickness is 19mm, the edge outlet temperature of the casting plate is controlled in the range of 515~544℃, and the middle outlet temperature of the casting plate is controlled in the range of 545~572℃. S6, Three-Stage Rolling: After passing through the mill pinch rolls, the slab enters the three-stand rolling mill for rolling. Before entering the three-stand mill, the slab must be rinsed and cooled with emulsion at a flow rate of 1000 L / min. The bending roll coefficients of the first, second, and third stands of the three-stand mill are 80%, 60%, and 40%, respectively. The inlet rolling temperature of the first stand is 480℃, the mass percentage of the sprayed emulsion is 3.42%, and the slab exit thickness is 8.5 mm. The inlet rolling temperature of the second stand is... The initial rolling temperature is 370℃, the mass percentage of sprayed emulsion is 3.42%, and the slab exit thickness is 3.8mm. The initial rolling temperature of the third stand of the three-stand rolling mill is 310℃, the mass percentage of sprayed emulsion is 3.42%, and the slab exit thickness is 1.8mm. The final rolling temperature of the aluminum coil after three-stand rolling is 190℃. The edge cracks of the aluminum coil after three-stand rolling are less than 1mm, and the number of edge cracks per meter is less than 10. The material exiting the third stand of the three-stand rolling mill is coiled into a coil to obtain a non-standard aluminum alloy single-layer brazed billet. Example 2

[0018] A method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks, comprising the following specific steps: S1. Smelting and Batching: Electrolytic aluminum liquid with a mass percentage of 13.81% and recycled aluminum scrap with a mass percentage of 86.19% are put into the smelting furnace to prepare aluminum melt. Mechanical stirring is carried out for 10-20 minutes using a slag removal cart. Sampling and testing are performed. Based on the test results, quick-dissolving silicon, iron, copper, manganese, titanium and zinc ingots are added to the smelting furnace. Electromagnetic stirring is turned on for 29 minutes to ensure that the alloy composition is adjusted to meet the requirements. The mass percentage of each component is as follows: Si: 3.45%, Fe: 0.45%, Cu: 0.025%, Mn: 1.45%, Mg: 0.01%, Zn: 2.05%, Ti: 0.052%, other individual impurities ≤0.03%, total ≤0.15%, balance Al; S2. Melt Purification Treatment: The qualified aluminum melt begins refining, using a combination of an HD2000 refining machine and manual refining. The HD2000 refining machine uses argon as the refining gas, maintaining an argon pressure of 0.58 MPa and a rotor speed of 526 rpm. Refining on the HD2000 machine takes 50-60 minutes to ensure effective melt refining and to achieve localized mixing and prevent segregation. Manual refining uses argon as a carrier to blow environmentally friendly refining agents into the aluminum melt. The refining agent is used at a rate of 2.8 kg per ton of molten aluminum. Manual refining should be carried out simultaneously on both sides of the furnace door, and a Z-shaped step refining method should be adopted to ensure that the refining areas overlap. The electromagnetic stirrer should be turned on throughout the refining process. After refining, the molten aluminum should be slag removed using a slag removal vehicle. The surface of the molten aluminum after slag removal should be mirror-like, and there should be no slag with an area exceeding 50 mm × 50 mm. After slag removal, the molten aluminum should be allowed to stand for 42 minutes. After refining, slag removal and standing, samples should be taken from both sides of the furnace door to test the composition. The content deviation of each alloy should be less than 0.02%. The furnace should then be started. S3. Grain refiner addition: After the furnace is started, the aluminum melt flows smoothly into the guide flow channel. Two sets of aluminum-titanium-boron wires are added to the melt at a speed of 3.1 m / min. The aluminum-titanium-boron wires are added at the inlet of the degassing box, with an interval of 30 cm between the aluminum-titanium-boron wires. The temperature of the aluminum-titanium-boron wires is controlled at 719℃. S4. Online degassing and filtration: The aluminum melt flows into the degassing box, where argon gas is introduced for online refining. The argon gas pressure is 0.54 MPa, and the speed of the three rotors is set to 508 rpm. After the aluminum melt comes out of the degassing box, it enters the plate filter box. Two ceramic filter plates of 30+40 ppi are placed in series in the plate filter box. The aluminum melt after degassing and filtration flows into the front box through the vertical flow stabilizer. S5, Continuous Casting: The temperature of the molten aluminum in the front box is maintained at 699℃. The molten aluminum flows into the casting cavity of the casting machine through the nozzle with a mixing zone. The heat of the molten aluminum is carried away by the circulating cooling water inside the steel strip. The molten aluminum 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 controlled at 7.4m / min, the billet thickness is 19mm, the edge outlet temperature of the casting plate is controlled in the range of 520~550℃, and the middle outlet temperature of the casting plate is controlled in the range of 545~575℃. S6, Three-Stage Rolling: After passing through the mill pinch rolls, the slab enters the three-stage rolling mill for rolling. Before entering the three-stage mill stand, the slab must be rinsed and cooled with emulsion at a flow rate of 1500 L / min. The bending roll coefficients of the first, second, and third stands of the three-stage rolling mill are 80%, 60%, and 40%, respectively. The inlet rolling temperature of the first stand is 500℃, the mass percentage of the sprayed emulsion is 3.51%, and the slab exit thickness is 8.8 mm. The inlet rolling temperature of the second stand is... The initial rolling temperature is 390℃, the mass percentage of sprayed emulsion is 3.51%, and the slab exit thickness is 4.0mm. The initial rolling temperature of the third stand of the three-stand rolling mill is 320℃, the mass percentage of sprayed emulsion is 3.51%, and the slab exit thickness is 2.0mm. The final rolling temperature of the aluminum coil after three-stand rolling is 220℃. The edge cracks of the aluminum coil after three-stand rolling are less than 1mm, and the number of edge cracks per meter is less than 10. The material exiting the third stand of the three-stand rolling mill is coiled into a coil to obtain a non-standard aluminum alloy single-layer brazed billet.

[0019] Since the continuous casting and rolling production line used in this invention can complete the rolling within one minute after the billet is cast, there is no low-temperature rolling situation in this production line. In Example 1 of this invention, the rolling passes are 19mm→8.5mm→3.8mm→1.8mm, and the calculated processing rates for each pass of the three-stand rolling are 55.26%, 55.29%, and 52.63%, respectively. In Example 2 of this invention, the rolling passes are 19mm→8.8mm→4.0mm→2.0mm, and the calculated processing rates for each pass of the three-stand rolling are 53.68%, 54.55%, and 50.00%, respectively. Since conventional cold rolling mills have an opening of only 10mm, they cannot roll 19mm billets. If a special cold rolling mill with a large opening is used to roll a 19mm thick billet at room temperature, the material is below the recrystallization temperature, resulting in high deformation resistance. The rolling time is limited by the maximum rolling force of the cold rolling mill. The estimated rolling passes are 19mm → 13.5mm → 9mm → 5.8mm → 3.5mm. After calculation, the rolling pass yields are only 28.95%, 33.33%, 35.56%, and 39.66%, respectively. The processing rate is much lower than that of the method of this invention.

[0020] Because the brazing filler metal used in the radiator industry uses multi-layer composite materials, and the alloy composition of each layer of the composite material varies significantly—for example, 3003 alloy contains approximately 1.2% Mn, 7072 alloy contains approximately 1.0% Zn, 4343 alloy contains approximately 7.0% Si, and 3003+Zn alloy contains both approximately 1.2% Mn and approximately 1.5% Zn—the alloys used in each layer of the multi-layer composite material vary depending on the application, and the coverage rate of each alloy, i.e., its proportion in the thickness of the multi-layer composite material, also varies. When processing and using the production waste of this type of brazing filler metal, it is impossible to detect the overall alloy composition. While direct testing of the surface layer allows for the detection of the surface alloy composition, the composition of the surface alloy cannot represent the overall composition of the core layer. On the other hand, two different brazing alloys each contain multiple layers of composite materials. Due to the different alloy composition of a certain single material in a layer, the overall alloy composition will be different. Even if the alloy composition of each composite material layer is the same in the two different brazing alloys, the overall alloy composition of the brazing alloy will be different due to the different coverage rates. Therefore, the overall alloy composition of this type of production waste can only be determined after it is completely melted and stirred evenly. If this type of production waste is used in another alloy, and the other alloy does not allow the presence of one or two of the three elements Mn, Si, and Zn, the alloy composition will not meet the requirements and the entire batch will be scrapped. However, the non-standard alloy of this invention contains Mn, Si, and Zn elements at relatively high levels, so it can be produced by digesting this type of recycled aluminum waste.

[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 low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks, characterized in that, Specifically, the following steps are included: S1. Smelting and Batching: Electrolytic aluminum liquid (5-15% by mass) and recycled aluminum waste (85-95% by mass) are placed into a smelting furnace to prepare aluminum melt. Samples are taken for testing. Based on the test results, quick-dissolving silicon, iron, copper, manganese, titanium, and zinc ingots are added to the smelting furnace. The mixture is electromagnetically stirred for 20-30 minutes to ensure that the alloy composition is adjusted to meet the requirements. The mass percentage of each component is as follows: Si: 2.5-3.5%, Fe: ≤0.5%, Cu: ≤0.05%, Mn: 1.1-1.5%, Mg: ≤0.02%, Zn: 1.7-2.1%, Ti: 0.045-0.055%, other individual impurities ≤0.03%, total ≤0.15%, with the balance being Al. S2. Melt purification treatment: Under electromagnetic stirring, the qualified aluminum melt is refined by a combination of refining machine and manual refining. After refining, the slag is removed and the furnace is opened after standing for 30 to 50 minutes. S3. Grain refiner addition: After the furnace is started, the aluminum melt flows smoothly into the guide channel, and aluminum titanium boron wire is added to the aluminum melt at a uniform speed. S4. Online degassing and filtration: The aluminum melt flows into the degassing box and the plate filter box in sequence for online degassing and filtration. After degassing and filtration, the aluminum melt flows into the front box through the vertical flow stabilizer. S5, Continuous casting: The temperature of the molten aluminum in the front box is 690℃~700℃. The molten aluminum flows into the casting chamber of the casting machine through the casting nozzle and solidifies in the casting chamber 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 7.0~7.5m / 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 540~580℃. S6. Three-Stage Rolling: After passing through the mill pinch rolls, 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 8.0-9.0 mm; the billet exit thickness of the second stand of the three-stage rolling mill is 3.7-4.2 mm; and the billet exit thickness of the third stand of the three-stage rolling mill is 1.7-2.0 mm. The material exiting the third stand of the three-stage rolling mill is directly coiled into a coil to obtain aluminum alloy single-layer brazed billet.

2. The method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks according to claim 1, characterized in that, In step S2, the refining gas is argon. Argon is used as a carrier to blow the refining agent into the aluminum melt. The amount of refining agent is 2-3 kg / ton of aluminum melt. The argon pressure is 0.5±0.1 MPa. The refining is carried out in a refining machine for 50-60 minutes. The rotor speed of the refining machine is 500±50 rpm.

3. The method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks according to claim 1, characterized in that, In step S3, two sets of aluminum-titanium-boron wires are added to the molten aluminum at a uniform speed of 3.0±1m / min at the inlet of the degassing box. The interval between the points where the aluminum-titanium-boron wires are added is 20-30cm, and the temperature at the points where the aluminum-titanium-boron wires are added is 710-730℃.

4. The method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks according to claim 1, characterized in that, In step S4, argon gas is introduced into the degassing box for online refining. The argon gas pressure is 0.5±0.05MPa, the rotation speed of the three rotors is set to 500±10 rpm, and the slag in the degassing box is removed at least once per hour.

5. The method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks according to claim 1, characterized in that, In step S5, a casting nozzle with a mixing zone is used.

6. The method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks according to claim 1, characterized in that, In step S6, before the cast plate enters the three-stand rolling mill, it must be rinsed and cooled with emulsion. The emulsion rinsing volume is 1000-1500 L / min.

7. The method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks according to claim 1, characterized in that, In step S6, the mass percentage of the sprayed emulsion on the first stand, second stand, and third stand of the three-stand rolling mill is 3.5 ± 0.1%.

8. The method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks according to claim 1, characterized in that, In step S6, the inlet rolling temperature of the first stand of the three-stand rolling mill is 460-540℃; the inlet rolling temperature of the second stand of the three-stand rolling mill is 340-410℃; the inlet rolling temperature of the third stand of the three-stand rolling mill is 260-340℃; the final rolling temperature of the aluminum coil after three-stand rolling is 190-220℃; the edge crack of the aluminum coil after three-stand rolling is less than 1mm; and the number of edge cracks per meter length is less than 10.

9. The method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks according to claim 1, characterized in that, In step S6, during continuous rolling, the bending roll coefficients of the first stand, the second stand, and the third stand of the three-stand rolling mill are 80%, 60%, and 40%, respectively.