A method for producing 3104 alloy billets with high recycled aluminum proportion and low carbon and environmental protection

Abstract

The application belongs to the technical field of aluminum alloy production, and particularly discloses a method for producing 3104 alloy blank with high recycled aluminum proportion and low carbon and environmental protection, which comprises the following steps: smelting, melt purification, online degassing and filtration, continuous casting and three continuous rolling processes, alloy component optimization, large proportion of recycled aluminum waste, Fe content improvement, intermetallic compounds formed by iron and manganese elements in aluminum alloy, these compounds can be used as heterogeneous nucleation, significantly refining the grain of the alloy during casting, and improving the performance of the 3104 alloy blank while replacing aluminum with iron, which can reduce the cost of main materials, in addition, due to the high rolling temperature at the inlet of each rack and the high final rolling temperature, the self-tempering effect is realized to eliminate dislocations in the material, improve the edge cracking condition of the blank, avoid the problem of belt breakage during rolling in the subsequent process, ensure safe production, reduce the cost of main materials, improve the performance of the blank, efficiently and high-quality produce the 3104 alloy blank, and realize the low-carbon and environmental protection target.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aluminum alloy production, and specifically discloses a method for producing 3104 alloy blank with high recycled aluminum proportion and low carbon and environmental protection. BACKGROUND

[0002] The 3104 aluminum alloy has medium strength and good plasticity and elongation, can meet the requirements of complex processing such as stamping, bending and stretching, and can ensure that the finished product is not easy to deform or break in use. As an Al-Mn alloy, the 3104 aluminum alloy is not easy to rust in the atmosphere, fresh water and some weak corrosive environments, and does not need additional complex corrosion prevention treatment. In addition, the 3104 aluminum alloy has good cold and hot working performance, can be made into thin plates, aluminum foils and profiles in various forms through cold rolling and hot rolling, and has stable welding performance, can be adapted to efficient processing of automatic production lines, and is widely used in food packaging, building decoration, transportation and daily hardware fields due to the above characteristics.

[0003] At present, domestic 3104 alloy blanks are generally produced by using hot-rolled blanks. For example, the manufacturing methods of 3104 aluminum alloy strips disclosed in existing patents CN104294194B and CN119351803A include multiple processes such as melting and casting, sawing and milling, homogenization heating, hot rolling and cold rolling. The production cycle is long, and the production cost is high. In addition, the finished product rate is low and the loss is high due to the sawing and milling process before the hot rolling production process, which further increases the production cost. Some enterprises also experimentally produce cast-rolled 3104 alloy products. For example, Chinese patent CN101912877B does not detail the cast-rolling related production process parameter information, but according to the production experience of most enterprises at present, the cast-rolled 3104 alloy blank has the characteristics of low production speed, easy roller sticking and large rolling force, which makes it difficult to control the profile, and seriously hinders the stable production of the cast-rolled blank. SUMMARY

[0004] In order to solve the problems in the background art, the application discloses a method for producing 3104 alloy blank with high recycled aluminum proportion and low carbon and environmental protection. The method uses a large proportion of recycled aluminum waste, optimizes the alloy composition, reduces the cost of main materials while improving the performance of the blank, efficiently and high-quality produces the 3104 alloy blank, and realizes the goal of low carbon and environmental protection.

[0005] To achieve the above-mentioned application purposes, the application adopts the following technical solutions:

[0006] A method for producing 3104 alloy blank with high recycled aluminum proportion and low carbon and environmental protection, comprising the following steps:

[0007] S1, smelting ingredients: the mass percentage of 5-10% of electrolytic aluminum liquid, 80-95% of recycled aluminum waste into the smelting furnace to prepare aluminum melt, sampling detection, according to the test results will be instant silicon, iron agent, copper agent, manganese agent, magnesium ingot and titanium agent into the smelting furnace, stirring evenly, the alloy composition adjustment qualified, wherein, each component mass percentage is: Si: 0.3-0.5%, Fe: 0.55-0.75%, Cu: 0.1-0.25%, Mn: 0.85-1.15%, Mg: 0.85-1.25%, Ti: 0.025-0.045%, other single impurity ≤0.03%, total ≤0.15%, the rest is Al;

[0008] S2, melt purification treatment: after the aluminum melt component adjustment qualified, start refining, at the same time using refining machine refining and artificial refining, using argon as refining gas, open electromagnetic stirring throughout the refining process, after refining the aluminum melt, after standing, slagging, after slagging, standing for 30-40 min, furnace;

[0009] S3, on-line degassing filtration: after the furnace, the aluminum melt flows into the degassing tank and the plate filter tank in turn through the flow tank for on-line degassing and filtration, the aluminum melt after degassing filtration flows into the front tank, aluminum titanium boron filament crystal refiner is uniformly added into the aluminum melt at the inlet of the degassing tank and the plate filter tank;

[0010] S4, continuous casting: the temperature of the aluminum melt in the front tank is 700-710℃, the aluminum melt flows into the casting machine cavity through the casting nozzle, the melt solidifies in the cavity to form a casting blank, the casting speed is 8.5-9.2m / min, and the thickness of the casting blank is 19mm;

[0011] S5, three continuous rolling: after the casting blank passes through the pinch roller of the rolling mill, it enters the three continuous rolling mill for rolling, the thickness of the plate blank at the outlet of the first rack of the three continuous rolling mill is 11.0-12.0mm, the thickness of the plate blank at the outlet of the second rack of the three continuous rolling mill is 7.0-8.0mm, the thickness of the plate blank at the outlet of the third rack of the three continuous rolling mill is 4.0-5.0mm, and the material at the outlet of the third rack is wound into a coil on the coiler to obtain the 3104 alloy blank product;

[0012] S6, inspection and packaging: the outlet plate strip edge of the aluminum strip needs to be inspected during three continuous rolling, and the crack edge is ≤2mm; after the material is discharged, sampling detection, tensile strength ≥295MPa, elongation ≥9.0%, grain size reaches national standard grade one, and after the inspection is qualified, it is packaged according to the requirements.

[0013] Further, in the step S1 of the method for producing 3104 alloy blank with high recycled aluminum proportion and low carbon environmental protection, before sampling detection, the aluminum melt in the smelting furnace is stirred evenly by using a slagging car for mechanical stirring.

[0014] Further, in the method for producing 3104 alloy blank with high proportion of recycled aluminum and low carbon and environmental protection, in step S1, when the magnesium ingot is added into the smelting furnace, the magnesium ingot is loaded into an iron frame welded by stainless steel, the iron frame loaded with the magnesium ingot is preheated on the surface of the melt for 10-20 min using a charging vehicle, then the iron frame is quickly lowered to be immersed below the liquid surface of the melt, and the iron frame is shaken to melt the magnesium ingot.

[0015] Further, in the method for producing 3104 alloy blank with high proportion of recycled aluminum and low carbon and environmental protection, in step S2, when the refiner is refined, the argon pressure is 0.5±0.1 MPa, the rotor speed is 500±50 r / min, and the refining time is 50-60 min, so as to ensure the refining effect of the melt and play a role in local stirring and uniformity, and avoid composition segregation.

[0016] Further, in the method for producing 3104 alloy blank with high proportion of recycled aluminum and low carbon and environmental protection, in step S3, argon is introduced into the degassing box for online refining, the argon pressure is 0.4±0.05 MPa, and the three groups of rotors rotate at a speed of 300±10 r / min.

[0017] Further, in the method for producing 3104 alloy blank with high proportion of recycled aluminum and low carbon and environmental protection, in step S3, the aluminum titanium boron wire is uniformly added into the aluminum melt at a speed of 3.5±0.5 m / min at the inlet of the degassing box, and the aluminum titanium boron wire is uniformly added into the aluminum melt at a speed of 1.5±0.5 m / min at the inlet of the plate filter box.

[0018] Further, in the method for producing 3104 alloy blank with high proportion of recycled aluminum and low carbon and environmental protection, in step S4, when continuous casting is performed, the casting nozzle used is the casting nozzle with a SL mixed zone, and the upper and lower steel belts are Y-shaped ceramic steel belts.

[0019] Further, in the method for producing 3104 alloy blank with high proportion of recycled aluminum and low carbon and environmental protection, in step S5, before the cast plate enters the three-stand continuous rolling mill, the cast plate must be washed and cooled using emulsion, the emulsion mass percentage concentration of the first stand of the three-stand continuous rolling mill is 4.5±0.1%, the emulsion mass percentage concentration of the second stand of the three-stand continuous rolling mill is 3.5±0.1%, and the emulsion mass percentage concentration of the third stand of the three-stand continuous rolling mill is 3.5±0.1%.

[0020] Further, in the method for producing 3104 alloy blank with high proportion of recycled aluminum and low carbon and environmental protection, in step S5, the plate blank inlet temperature of the first stand of the three-stand continuous rolling mill is 480-550℃, the plate blank outlet temperature of the first stand of the three-stand continuous rolling mill is 400-470℃, the plate blank inlet temperature of the second stand of the three-stand continuous rolling mill is 380-450℃, the plate blank outlet temperature of the second stand of the three-stand continuous rolling mill is 270-340℃, the plate blank inlet temperature of the third stand of the three-stand continuous rolling mill is 250-320℃, and the plate blank outlet temperature of the third stand of the three-stand continuous rolling mill is 150-220℃.

[0021] Compared with the prior art, the present application has the following advantages:

[0022] 1. The method for producing 3104 alloy billets with high recycled aluminum proportion and low carbon and environmental protection, optimizes alloy composition, increases Fe content, and intermetallic compounds are formed by iron and manganese and other elements in the aluminum alloy, which can act as heterogeneous nucleation to significantly refine the grains of the alloy during casting, and increase the Fe content to improve the performance of the 3104 alloy billets, replace aluminum with iron to reduce the cost of main materials, and due to the high rolling temperature at the inlet of each stand and the high final rolling temperature, the self-tempering effect is realized to eliminate dislocations in the material and improve the billet edge cracking condition, avoid belt breakage due to edge cracking during subsequent rolling, and ensure safe production;

[0023] 2. The method for producing 3104 alloy billets with high recycled aluminum proportion and low carbon and environmental protection can use recycled aluminum waste in a large proportion, combined with appropriate refining treatment process to ensure the quality of the melt, realize stable quality and standard during subsequent rolling of the billets, rely on the good cooling effect of the Hazelette casting machine to realize a production efficiency of more than 35t / h, and realize efficient production. DETAILED DESCRIPTION

[0024] The present application will be further explained and described below in conjunction with examples, which cannot limit the protection scope of the present application, and the purpose of disclosing the present application is to protect all technical improvements within the scope of the present application. Example 1

[0025] The method for producing 3104 alloy billets with high recycled aluminum proportion and low carbon and environmental protection has the following specific steps:

[0026] S1, melting and batching: placing 5.85% of electrolytic aluminum liquid and 94.15% of recycled aluminum waste into a melting furnace to prepare an aluminum melt, using a slagging car for mechanical stirring to uniformly stir the aluminum melt in the melting furnace, then sampling and detecting, according to the detection result, adding quick-acting silicon, iron agent, copper agent, manganese agent, magnesium ingot and titanium agent into the melting furnace, and electromagnetically stirring for 30min, adjusting the alloy composition to be qualified, when adding magnesium ingot into the melting furnace, the magnesium ingot is loaded into an iron frame welded from stainless steel, the iron frame loaded with magnesium ingot is preheated on the surface of the melt for 12min using a charging car, then the iron frame is quickly lowered to be immersed below the surface of the melt, and the iron frame is shaken back and forth and left and right to melt the magnesium ingot, wherein the mass percentage of each component is: Si: 0.35%, Fe: 0.58%, Cu: 0.15%, Mn: 0.89%, Mg: 0.87%, Ti: 0.026%, other single impurities ≤0.03%, total ≤0.15%, and the balance is Al;

[0027] S2, melt purification treatment: the qualified aluminum melt is started to refine, the whole process is required to open electromagnetic stirring, at the same time, HD2000 refining and manual refining are used in parallel, the refining time is 50 min, the refining effect of the melt is ensured, and the local stirring uniformity is played, the component segregation is avoided, the HD2000 refining uses argon as the refining gas, the argon pressure is ensured to be 0.48 MPa, the rotor is kept at 460 r / min, the manual refining uses argon as the refining gas, after the refining, the melt is placed for 20 min, and then the slagging operation is performed by using the slagging car, the surface of the aluminum melt after the slagging is mirror-like, and the floating slag with an area of more than 50 mm*50 mm should not be reserved, and the aluminum melt is placed for 32 min after the slagging, and the furnace is started;

[0028] S3, on-line degassing and filtering: after the furnace is started, the aluminum melt flows into the degassing tank and the plate filter tank in sequence through the flow guide chute for on-line degassing and filtering, the degassing tank is required to be slagged once per hour, the aluminum melt flows into the degassing tank, argon is introduced into the degassing tank for on-line refining, the argon pressure is 0.38 MPa, the rotational speed of the three rotors is set to 298 min, the aluminum melt flows into the plate filter tank after the degassing tank, two ceramic filter plates with 30+40 ppi are placed in series in the plate filter tank, the gap between the filter plate in the plate filter tank and the lining in the tank body needs to be tightly sealed by using asbestos, the filter plate is tightly pressed by using a pressing block, the aluminum melt after the degassing and filtering flows into the front tank through the vertical flow stabilizer, the aluminum titanium boron wire is uniformly added into the aluminum melt at the speed of 3.0 m / min at the inlet of the degassing tank, the aluminum titanium boron wire is uniformly added into the aluminum melt at the speed of 2.0 m / min at the inlet of the plate filter tank, and the temperature of the aluminum titanium boron wire adding point is 720℃;

[0029] S4, continuous casting: the temperature of the aluminum melt in the front tank is kept at 702℃, the liquid level height of the front tank needs to be fluctuated by less than 2 mm, the aluminum melt flows into the casting cavity of the casting machine through the casting nozzle, the casting nozzle used is the SL casting nozzle with a mixing zone, the heat of the aluminum melt is taken away by the circulating cooling water inside the steel belt through the steel belt, the melt is solidified to form a casting blank in the casting cavity, and the casting blank is out of the plate with the same direction rotation of the upper and lower steel belts, the upper and lower steel belts are Y type ceramic steel belts, the casting speed is 8.8 m / min, and the thickness of the casting blank is 19 mm;

[0030] S5, three-stand rolling: after the casting blank passes through the pinch rolls of the rolling mill, it enters the three-stand rolling mill for rolling. Before the casting plate enters the rolling mill stand, it must be rinsed with an emulsion for cooling. The amount of emulsion used for rinsing is 2000 L / min. The mass percentage concentration of the emulsion in the first stand of the three-stand rolling mill is 4.45%. The thickness of the slab at the outlet is 11.0 mm. The temperature of the slab at the inlet of the first stand of the three-stand rolling mill is 520℃. The temperature of the slab at the outlet of the first stand of the three-stand rolling mill is 440℃. The mass percentage concentration of the emulsion in the second stand of the three-stand rolling mill is 3.42%. The thickness of the slab at the outlet is 7.0 mm. The temperature of the slab at the inlet of the second stand of the three-stand rolling mill is 420℃. The temperature of the slab at the outlet of the second stand of the three-stand rolling mill is 280℃. The mass percentage concentration of the emulsion in the third stand of the three-stand rolling mill is 3.48%. The thickness of the slab at the outlet is 4.0 mm. The temperature of the slab at the inlet of the third stand of the three-stand rolling mill is 260℃. The temperature of the slab at the outlet of the third stand of the three-stand rolling mill is 190℃. The material at the outlet of the three stands is coiled on a coiler to obtain the 3104 alloy blank product.

[0031] S6, inspection and packaging: the edges of the aluminum strip are inspected for cracks during three-stand rolling. The total crack length of a whole coil is ≤1 mm. After the material is discharged from the rolling mill, the thickness, width, end face quality, surface quality and other quality indicators of the material are inspected. The mechanical properties of the product are detected by sampling. The tensile strength is 299 MPa and the elongation is ≥9.5%. The grain size is detected by sampling and pickling. The grain size reaches the national standard level one. After the inspection is passed, the material is packaged according to the packaging requirements using hardboard, plastic film, desiccant and wooden supports. After the packaging is completed, a material label is attached to the outside of the hardboard. The label must contain information such as the alloy, state, specification, net weight, gross weight and packaging date. Example 2

[0032] The specific steps of the method for producing the 3104 alloy blank with a high proportion of recycled aluminum and low carbon environmental protection are as follows:

[0033] S1, melting and batching: the electrolytic aluminum liquid with a mass percentage of 9.21% and the recycled aluminum scrap with a mass percentage of 90.79% are put into a melting furnace to prepare an aluminum melt. After the aluminum melt in the melting furnace is uniformly stirred by using a slag skimming car for mechanical stirring, sampling is performed. According to the detection results, fast-acting silicon, iron agent, copper agent, manganese agent, magnesium ingot and titanium agent are added to the melting furnace. The electromagnetic stirring is turned on for 40 min to ensure that the alloy composition adjustment is qualified. When the magnesium ingot is added to the melting furnace, the magnesium ingot is loaded into a stainless steel welded iron frame. The iron frame loaded with the magnesium ingot is preheated on the surface of the melt for 20 min by using a charging car. Then the iron frame is quickly lowered to be immersed below the surface of the melt and shaken back and forth and left and right to melt the magnesium ingot. The mass percentages of the components are as follows: Si: 0.48%, Fe: 0.72%, Cu: 0.23%, Mn: 1.12%, Mg: 1.21%, Ti: 0.044%, other single impurities ≤0.03%, total ≤0.15%, and the balance is Al.

[0034] S2, melt purification treatment: the qualified aluminum melt is started to refine, the whole process is required to open electromagnetic stirring, at the same time, HD2000 refining and manual refining are used in parallel, the refining time is 60 min, the refining effect of the melt is ensured, and the local stirring uniformity is played, the component segregation is avoided, the HD2000 refining uses argon as the refining gas, the argon pressure is ensured to be 0.58 MPa, the rotor is kept at 535 r / min, the manual refining uses argon as the refining gas, after the refining, the melt is placed for 15 min, and then the slagging operation is performed by using the slagging car, the surface of the aluminum melt after the slagging is mirror-like, and the floating slag with an area of more than 50 mm*50 mm is not allowed to remain, and the aluminum melt is placed for 39 min after the slagging, and the furnace is started;

[0035] S3, on-line degassing and filtering: after the furnace is started, the aluminum melt flows into the degassing tank and the plate filter tank in sequence through the flow guide chute for on-line degassing and filtering, the degassing tank is required to be slagged once per hour, the aluminum melt flows into the degassing tank, argon is introduced into the degassing tank for on-line refining, the argon pressure is 0.43 MPa, the rotational speed of the three rotors is set to 308 r / min, the aluminum melt flows into the plate filter tank after the degassing tank, two ceramic filter plates with 30+40 ppi are placed in series in the plate filter tank, the gap between the filter plate and the lining in the plate filter tank needs to be tightly sealed by using asbestos, and the filter plate is tightly pressed by using a pressing block, the aluminum melt after the degassing and filtering flows into the front tank through the vertical flow stabilizer, the aluminum titanium boron wire is uniformly added into the aluminum melt at the speed of 4.0 m / min at the inlet of the degassing tank, the aluminum titanium boron wire is uniformly added into the aluminum melt at the speed of 1.0 m / min at the inlet of the plate filter tank, and the temperature of the aluminum titanium boron wire adding point is 730 DEG C;

[0036] S4, continuous casting: the temperature of the aluminum melt in the front tank is kept at 709 DEG C, the liquid level height of the front tank needs to be fluctuated by less than 2 mm, the aluminum melt flows into the casting cavity of the casting machine through the casting nozzle, the casting nozzle used is the SL casting nozzle with a mixing zone, the heat of the aluminum melt is taken away by the circulating cooling water inside the steel belt through the steel belt, the melt is solidified to form a casting blank in the casting cavity, and the casting blank is out of the plate along with the same direction rotation of the upper and lower steel belts, the casting speed is controlled to be 9.1 m / min, and the thickness of the casting blank is 19 mm;

[0037] S5, three continuous rolling: after the slab over-rolling machine pinch roll, into the three continuous rolling mill rolling, the cast slab into the continuous rolling mill before entering, must be washed with emulsion cooling, emulsion flushing volume is 2200L / min, three continuous rolling mill first rack emulsion mass percentage concentration is 4.58%, slab exit thickness is 11.9mm, three continuous rolling mill first rack slab inlet temperature is 540, three continuous rolling mill first rack slab outlet temperature is 460℃; three continuous rolling mill second rack emulsion mass percentage concentration is 3.57%, slab exit thickness is 7.8mm, three continuous rolling mill second rack slab inlet temperature is 440℃, three continuous rolling mill second rack slab outlet temperature is 300℃; three continuous rolling mill third rack emulsion mass percentage concentration is 3.52%, slab exit thickness is 4.8mm, three continuous rolling mill third rack slab inlet temperature is 280℃, three continuous rolling mill third rack slab outlet temperature is 210℃, three rack outlet material is coiled on the coiler, get 3104 alloy blank finished product;

[0038] S6, inspection and packaging: the edge of the aluminum strip is inspected when the edge of the aluminum strip is rolled, and no edge is found in the whole roll; after the material is discharged, the material thickness, width, end face quality, surface quality and other quality indicators are inspected, the mechanical properties are detected, the tensile strength is 302MPa, the elongation is greater than or equal to 9.9%, and the grain size is detected by sampling pickling, and the grain size reaches the national standard first grade; after the inspection is qualified, the hardboard, plastic film, desiccant and wooden support are used for packaging according to the packaging requirements, the material label is pasted on the outside of the hardboard after the packaging is completed, and the label needs to contain alloy, state, specification, net weight, gross weight and packaging date and other information.

[0039] The part of the application not described in detail is the prior art.

[0040] In order to disclose the inventive purpose of the present application, the examples selected in the present application are currently considered to be appropriate, but it should be understood that the present application is intended to include all changes and improvements of the embodiments within the scope of the present application.

Claims

1. A method for producing 3104 alloy billets with high recycled aluminum ratio and low carbon and environmental protection, characterized in that, The method comprises the following steps: S1, smelting ingredients: placing 5-10% of electrolytic aluminum liquid and 80-95% of recycled aluminum waste into a smelting furnace to prepare an aluminum melt, sampling and detecting, and adding instant silicon, iron agent, copper agent, manganese agent, magnesium ingot and titanium agent into the smelting furnace according to the detection result, and stirring uniformly, and adjusting the alloy components to be qualified, wherein the mass percentage of each component is as follows: Si: 0.3-0.5%, Fe: 0.55-0.75%, Cu: 0.1-0.25%, Mn: 0.85-1.15%, Mg: 0.85-1.25%, Ti: 0.025-0.045%, other single impurities: ≤0.03%, total impurities: ≤0.15%, and the balance is Al; when the magnesium ingot is added into the smelting furnace, the magnesium ingot is loaded into an iron frame welded by stainless steel, the iron frame loaded with the magnesium ingot is preheated on the surface of the melt for 10-20 min by using a feeding vehicle, and then the iron frame is quickly lowered to be immersed below the surface of the melt, and the magnesium ingot is melted by shaking the iron frame; S2, melt purification treatment: after the aluminum melt is adjusted to be qualified, refining is started, and the refining is performed by using a refining machine and manual refining, argon is used as the refining gas, the electromagnetic stirring is turned on during the whole refining process, and after the aluminum melt is refined, slagging is performed after standing, and the aluminum melt is taken out after standing for 30-40 min; S3, online degassing and filtering: after the aluminum melt is taken out, the aluminum melt flows into a degassing tank and a plate filter tank in sequence through a flow guide chute to perform online degassing and filtering, the aluminum melt after degassing and filtering flows into a front tank, aluminum titanium boron wires are added into the aluminum melt at the inlet of the degassing tank at a uniform speed of 3.5±0.5 m / min, and the aluminum titanium boron wires are added into the aluminum melt at the inlet of the plate filter tank at a uniform speed of 1.5±0.5 m / min; S4, continuous casting: the temperature of the aluminum melt in the front tank is 700-710℃, the aluminum melt flows into a casting cavity of a casting machine through a casting nozzle, the casting nozzle used is a SL band mixed zone casting nozzle, the upper and lower steel bands are Y-shaped ceramic steel bands, the melt is solidified in the casting cavity to form a cast blank, and the cast blank is discharged out of the plate along with the same direction rotation of the upper and lower steel bands, the casting speed is 8.5-9.2 m / min, and the thickness of the cast blank is 19 mm; S5, three-stand rolling: after the cast blank passes through the pinch roll, the cast blank enters 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 11.0-12.0 mm, the thickness of the plate blank at the outlet of the second stand of the three-stand rolling mill is 7.0-8.0 mm, the thickness of the plate blank at the outlet of the third stand of the three-stand rolling mill is 4.0-5.0 mm, and the material at the outlet of the third stand of the three-stand rolling mill is wound into a coil on a coiler to obtain a 3104 alloy blank product; S6, inspection and packaging: when the aluminum strip passes through the three-stand rolling mill, the edge cracks of the outlet plate strip need to be inspected, and the edge crack is ≤2 mm; after the material is discharged, sampling and detection are performed, the tensile strength is ≥295 MPa, the elongation is ≥9.0%, the grain size reaches the national standard level one, and after the inspection is qualified, the material is packaged according to the requirements.

2. The process for low carbon eco-friendly production of 3104 alloy billets with high percentage of secondary aluminium as claimed in claim 1 wherein, In step S1, before sampling and detection, the aluminum melt in the smelting furnace is stirred uniformly by using a slagging vehicle for mechanical stirring.

3. The process for low carbon eco-friendly production of 3104 alloy billets with high percentage of secondary aluminium as claimed in claim 1 wherein, In step S2, the argon pressure is 0.5±0.1 MPa, the rotor rotating speed is 500±50 rpm, and the refining time is 50-60 min, so as to ensure the refining effect of the melt and to realize local stirring and homogenization, thereby avoiding composition segregation.

4. The process for low carbon eco-friendly production of 3104 alloy billets with high percentage of secondary aluminium as claimed in claim 1 wherein, In step S3, argon is introduced into the degassing tank for online refining, the argon pressure is 0.4±0.05 MPa, and the rotating speed of the three rotors is 300±10 rpm.

5. The process for low carbon eco-friendly production of 3104 alloy billets with high percentage of secondary aluminium as claimed in claim 1 wherein, In step S5, the cast slab is washed and cooled by using emulsion before entering the continuous rolling rack, the emulsion mass percentage concentration of the first rack of the three continuous rolling racks is 4.5±0.1%, the emulsion mass percentage concentration of the second rack of the three continuous rolling racks is 3.5±0.1%, and the emulsion mass percentage concentration of the third rack of the three continuous rolling racks is 3.5±0.1%.

6. The process for low carbon eco-friendly production of 3104 alloy billets with high percentage of secondary aluminium as claimed in claim 1 wherein, In step S5, the slab inlet temperature of the first rack of the three continuous rolling racks is 480-550℃, and the slab outlet temperature of the first rack of the three continuous rolling racks is 400-470℃; the slab inlet temperature of the second rack of the three continuous rolling racks is 380-450℃, and the slab outlet temperature of the second rack of the three continuous rolling racks is 270-340℃; and the slab inlet temperature of the third rack of the three continuous rolling racks is 250-320℃, and the slab outlet temperature of the third rack of the three continuous rolling racks is 150-220℃.