A method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks

Abstract

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 billets. Due to the high content of Mn, Si, and Zn alloy components, recycled aluminum waste can be used in large proportion, achieving the goal of low carbon and environmental protection. The non-standard aluminum alloy single-layer brazing billet is produced by continuous casting and rolling process. Because the entry rolling temperature of each stand of the three-stand rolling mill is high, and the final rolling temperature is also relatively 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, because there are fewer internal dislocations and lower stress in the material, it is easier for subsequent processes to roll with a high processing rate, reducing the number of rolling passes. It can achieve the production of 1650mm wide billets, greatly improving the downstream production efficiency and achieving a production efficiency of more than 30t per hour.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of aluminum alloy production, and particularly discloses a method for low-carbon and efficient production of non-national standard aluminum alloy single-layer brazing blank. BACKGROUND

[0002] The brazing filler is a core component of an automobile radiator, and its core function is to firmly weld the multi-layer metal structure of the radiator and ensure that heat can be efficiently transferred to the outside. The brazing filler is melted at high temperature to weld the dispersed radiator pipes, main side plates and other components into a sealed whole. The brazing filler not only needs to withstand the pressure of the cooling liquid, but also needs to resist the vibration impact during the driving of the automobile, and also needs to ensure that the radiator does not leak and does not collapse. The welding points / welding seams formed by the brazing filler need to have good thermal conductivity to quickly transfer the heat of the cooling liquid in the radiator pipes to the radiator fins, so as to ensure stable heat dissipation efficiency.

[0003] At present, the brazing filler is usually made of multi-layer composite materials. Since the manufacturing process of the multi-layer brazing filler is complex and the production cost is high, the alloy composition of each layer of the multi-layer composite material is different, resulting in that the production waste alloy composition is very complex, and the production waste contains a plurality of high-content alloy elements and is not easy to be used. Therefore, in the industry, single-layer brazing filler is used in scenes where the heat dissipation demand is not extreme. Since the single-layer brazing filler does not need the complex superposition and step-by-step welding of the multi-layer brazing filler, the amount of brazing filler and the production process are reduced, and the cost is reduced, so the single-layer brazing filler is more and more favored by the market.

[0004] At present, the single-layer brazing blank is produced by casting and rolling blank, and the blank quality is unstable, the production has large cracks and edges, and the production efficiency is low. Chinese patent CN105229182B discloses a manufacturing method of single-layer aluminum alloy material with heating and joining functions, which comprises a casting process of double-roller continuous casting and rolling, a cold rolling process and an annealing process of the rolled plate in the cold rolling process. In the cold rolling process, the aluminum coil produced by the manufacturing method is prone to edge cracks and peeling problems. When there are large cracks in the edge of the coil, the coil is prone to breakage risk in the cold rolling process. Chinese patent CN113174548B discloses a single-layer aluminum alloy fin material for brazing and a manufacturing method thereof. In the production scheme, the speed of double-roller continuous casting and rolling is only 550-700 mm / min, and the hourly output is less than 1 t, and the efficiency is low. It is urgent to develop a single-layer brazing blank efficient production method, to improve the blank quality, reduce the edge and crack problems, facilitate the rolling production in the subsequent process, and further reduce the comprehensive production cost. SUMMARY

[0005] In order to solve the problems in the background art, the application discloses a method for low-carbon and efficient production of non-national standard aluminum alloy single-layer brazing blank, which uses a large proportion of recycled aluminum waste to produce the required blank efficiently and with high quality, and realizes the goals of low carbon, environmental protection and high efficiency.

[0006] To achieve the above-mentioned purposes of the application, the following technical solutions are adopted:

[0007] A method for producing non-national standard aluminum alloy single-layer brazing blank with low carbon and high efficiency, specifically comprising the following steps:

[0008] S1, smelting and batching: placing electrolytic aluminum liquid with a mass percentage of 5-15% and recycled aluminum scrap with a mass percentage of 85-95% into a smelting furnace to prepare an aluminum melt, taking a sample for detection, and adding fast-acting silicon, iron agent, copper agent, manganese agent, titanium agent and zinc ingot into the smelting furnace according to the detection results, and performing electromagnetic stirring for 20-30 min to ensure that the alloy component adjustment is qualified, wherein 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%, and other single impurities: ≤0.03%, and the total of the impurities: ≤0.15%, and the balance: Al;

[0009] S2, melt purification treatment: under electromagnetic stirring, refining the aluminum melt with qualified batching by combining a refiner with manual refining, performing slagging after refining, and standing for 30-50 min before starting the furnace;

[0010] S3, grain refiner addition: after starting the furnace, the aluminum melt flows into a flow guide chute stably, and aluminum titanium boron wires are added into the aluminum melt at a uniform speed;

[0011] S4, online degassing and filtering: the aluminum melt flows into a degassing tank and a plate filter tank in sequence for online degassing and filtering, and the aluminum melt after degassing and filtering flows into a front tank through a vertical flow stabilizer;

[0012] S5, continuous casting: the temperature of the aluminum melt in the front tank is 690-700℃, the aluminum melt flows into a casting cavity of a casting machine through a casting nozzle to solidify into a casting blank in the casting cavity, the casting blank is discharged as a plate with the same direction rotation of the upper and lower steel belts, the casting speed is 7.0-7.5 m / min, the thickness of the casting blank is 19 mm, the outlet temperature of the edge of the casting plate is 500-560℃, and the outlet temperature of the middle of the casting plate is 540-580℃;

[0013] S6, three-stand rolling: after the casting blank passes through the pinch rolls of a rolling mill, the casting blank is rolled by a three-stand rolling mill, the thickness of the plate blank at the outlet of the first stand of the three-stand rolling mill is 8.0-9.0 mm, the thickness of the plate blank at the outlet of the second stand of the three-stand rolling mill is 3.7-4.2 mm, the thickness of the plate blank at the outlet of the third stand of the three-stand rolling mill is 1.7-2.0 mm, and the material at the outlet of the third stand of the three-stand rolling mill is directly coiled to obtain an aluminum alloy single-layer brazing blank.

[0014] Further, in the method for producing the non-national standard aluminum alloy single-layer brazing blank with low carbon and high efficiency, in the step S2, the refining gas is argon, the argon is used as a carrier to blow the refining agent into the aluminum melt, the refining agent is 2-3 kg per ton of aluminum melt, the argon pressure is 0.5±0.1 MPa, the refining machine is used for refining for 50-60 min, and the rotor speed of the refining machine is 500±50 r / min.

[0015] Further, in the method for producing the non-national standard aluminum alloy single-layer brazing blank with low carbon and high efficiency, in the step S3, two groups of aluminum-titanium-boron wires are added into the aluminum melt at the inlet of the degassing box at a uniform speed of 3.0±1 m / min, the aluminum-titanium-boron wire adding points are spaced 20-30 cm apart, and the aluminum-titanium-boron wire adding point temperature is 710-730℃.

[0016] Further, in the method for producing the non-national standard aluminum alloy single-layer brazing blank with low carbon and high efficiency, in the step S4, argon is introduced into the degassing box for online refining, the argon pressure is 0.5±0.05 MPa, the rotor speeds of the three groups of rotors are set to 500±10 r / min, and the slag is removed from the degassing box at least once per hour.

[0017] Further, in the method for producing the non-national standard aluminum alloy single-layer brazing blank with low carbon and high efficiency, in the step S5, the casting nozzle is a casting nozzle with a mixing zone.

[0018] Further, in the method for producing the non-national standard aluminum alloy single-layer brazing blank with low carbon and high efficiency, in the step S6, before entering the three-stand rolling mill, the cast plate needs to be cooled by using emulsion for flushing, and the emulsion flushing amount is 1000-1500 L / min.

[0019] Further, in the method for producing the non-national standard aluminum alloy single-layer brazing blank with low carbon and high efficiency, in the step S6, the mass percentage of the emulsion sprayed by the first stand, the second stand and the third stand of the three-stand rolling mill is 3.5±0.1%.

[0020] Further, in the method for producing the non-national standard aluminum alloy single-layer brazing blank with low carbon and high efficiency, in the step S6, the rolling temperature at the inlet of the first stand of the three-stand rolling mill is 460-540℃, the rolling temperature at the inlet of the second stand of the three-stand rolling mill is 340-410℃, the rolling temperature at the inlet of the third stand of the three-stand rolling mill is 260-340℃, the final rolling temperature of the aluminum coil after the three-stand rolling is 190-220℃, the edge crack of the aluminum coil after the three-stand rolling is less than 1 mm, and the number of edge cracks per meter of length is less than 10.

[0021] Further, in the method for producing the non-national standard aluminum alloy single-layer brazing blank with low carbon and high efficiency, in the step S6, during the continuous rolling, the bending roll coefficients of the first stand of the three-stand rolling mill, the second stand of the three-stand rolling mill and the third stand of the three-stand rolling mill are 80%, 60% and 40%, respectively.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (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.

[0024] (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.

[0025] (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

[0026] 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

[0027] A method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks, comprising the following specific steps:

[0028] 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.

[0029] 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.

[0030] 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℃.

[0031] 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.

[0032] 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℃.

[0033] 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

[0034] A method for low-carbon and high-efficiency production of non-standard aluminum alloy single-layer brazing blanks, comprising the following specific steps:

[0035] 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;

[0036] 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.

[0037] 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℃.

[0038] 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.

[0039] 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℃.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] The parts of this invention not described in detail are prior art.

[0044] 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 high efficient production of non-standards aluminium alloy single layer brazing blank, characterized in that, Specifically comprising the following steps: S1, smelting ingredients: the mass percentage of 5-15% of electrolytic aluminum liquid, 85-95% of recycled aluminum waste into the smelting furnace to prepare aluminum melt, sampling detection, according to the test results will be added to the smelting furnace, electromagnetic stirring 20-30 min, to ensure that the alloy component adjustment is qualified, wherein the mass percentage of each component is: 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 single impurity ≤0.03%, total ≤0.15%, the balance is Al; S2, melt purification treatment: under electromagnetic stirring, the refining machine and artificial refining combination way is used to refine the ingredients qualified aluminum melt, after refining, slagging, after slagging, standing for 30-50 min, then the furnace is started; S3, grain refiner addition: after the furnace is started, the aluminum melt flows into the flow tank, and the aluminum titanium boron wire is uniformly added into the aluminum melt; S4, on-line degassing and filtration: the aluminum melt flows into the degassing tank and the plate filter tank in sequence for on-line degassing and filtration, and the aluminum melt after degassing and filtration flows into the front tank through the vertical flow stabilizer; S5, continuous casting: the temperature of the aluminum melt in the front tank is 690-700 DEG C, the aluminum melt flows into the casting cavity of the casting machine through the casting nozzle, solidifies in the casting cavity to form a casting blank, and the casting blank is discharged with the same direction rotation of the upper and lower steel belts, the casting speed is 7.0-7.5 m / min, the thickness of the casting blank is 19 mm, the outlet temperature of the edge of the casting plate is 500-560 DEG C, and the outlet temperature of the middle of the casting plate is 540-580 DEG C; S6, three-stand rolling: the casting blank passes through the pinch roll of the rolling mill and enters the three-stand rolling mill for rolling, the thickness of the casting blank at the outlet of the first stand of the three-stand rolling mill is 8.0-9.0 mm, the thickness of the casting blank at the outlet of the second stand of the three-stand rolling mill is 3.7-4.2 mm, the thickness of the casting blank at the outlet of the third stand of the three-stand rolling mill is 1.7-2.0 mm, and the material at the outlet of the third stand of the three-stand rolling mill is directly coiled to obtain an aluminum alloy single-layer brazing blank.

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, the argon is used as a carrier to blow the refining agent into the aluminum melt, the amount of the refining agent is 2-3 kg per ton of aluminum melt, the argon pressure is 0.5±0.1 MPa, the refining machine is used for refining for 50-60 min, and the rotating speed of the rotor of the refining machine is 500±50 r / min.

3. The method of claim 1, wherein the non-ASTM aluminum alloy single-layer brazing sheet is produced with low carbon and high efficiency. In step S3, two groups of aluminum titanium boron wires are uniformly added into the aluminum melt at the inlet of the degassing tank at a speed of 3.0±1 m / min, the interval between the aluminum titanium boron wire adding points is 20-30 cm, and the temperature of the aluminum titanium boron wire adding point is 710-730 DEG C.

4. The method of claim 1, wherein the non-ASTM aluminum alloy single-layer brazing sheet is produced with low carbon and high efficiency. In step S4, argon is introduced into the degassing tank for on-line refining, the argon pressure is 0.5±0.05 MPa, the rotating speed of the three rotors is set to 500±10 r / min, and the slagging in the degassing tank is carried out at least once per hour.

5. The method of claim 1, wherein the non-ASTM aluminum alloy single layer brazing blank is produced with low carbon and high efficiency. In step S5, the casting nozzle adopts a casting nozzle with a mixing zone.

6. The method of claim 1, wherein the non-ASTM aluminum alloy single-layer brazing sheet is produced with low carbon and high efficiency. In step S6, before the casting plate enters the three-stand rolling mill, the casting plate must be washed and cooled by using an emulsion, and the washing amount of the emulsion is 1000-1500 L / min.

7. The method of claim 1, wherein the non-ASTM aluminum alloy single layer brazing blank is produced with low carbon and high efficiency. In step S6, the first stand, the second stand and the third stand of the three-stand tandem mill spray the mass percentage of the emulsion is 3.5±0.1%.

8. The method of claim 1, wherein the non-ASTM aluminum alloy single layer brazing blank is produced with low carbon and high efficiency. In step S6, the first stand of the three-stand tandem mill has an entry rolling temperature of 460-540℃; the second stand of the three-stand tandem mill has an entry rolling temperature of 340-410℃; the third stand of the three-stand tandem mill has an entry rolling temperature of 260-340℃, the final rolling temperature of the aluminum coil after the three-stand tandem rolling is 190-220℃, the edge crack of the aluminum coil after the three-stand tandem 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 the tandem rolling, the bending roll coefficients of the first stand, the second stand and the third stand of the three-stand tandem mill are 80%, 60% and 40% respectively.