A method for manufacturing ultra-wide aluminum foil for radiator

Abstract

The present invention introduces a method for manufacturing an oversized aluminum foil for a radiator, and the specific steps are: smelting-casting-rough rolling-edge cutting-finishing-annealing; during smelting, solid materials and electrolytic aluminum liquid are added, and the temperature of the solid materials in the furnace is raised to not less than 720°C by stewing the furnace without ignition; after slagging, the alloy composition in the furnace is adjusted, and after inert gas refining, it is poured into a heat preservation furnace for casting and rolling; three rough rolling passes; and four finishing passes. The present invention increases the proportion of electrolytic aluminum liquid and reduces the proportion of solid materials, adopts a stewing method, reduces energy consumption and burning loss, saves energy and reduces emissions, and reduces production costs; adjusts the alloy composition ratio and refining additives in the furnace, and adopts nitrogen blowing to effectively remove oxides and impurities in the aluminum liquid to ensure the purification effect, so as to increase the width of the cast coil and reduce the amount of trimming; by controlling the rolling tension, the edge is prevented from being easily warped due to poor cooling of the edge; reduces the number of production passes, shortens the production time, and improves the production efficiency of the wide-width rolling mill.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum foil manufacturing, and in particular to a method for manufacturing an oversized aluminum foil for a radiator. Background Art

[0002] With the development of economy, the aluminum foil market is highly competitive. Aluminum foil for radiator belongs to the lower-end foil products. Price war is the main way to gain market share. Price reduction will reduce the profit of manufacturers. Only by tapping the internal potential, reducing production costs, improving production efficiency and promoting energy conservation and consumption reduction can aluminum foil manufacturers focus on.

[0003] For a rolling mill with a roll width of 2000mm, there is about 50mm of the edge that does not pass through the water tank. The maximum width of the roll that can be used is 1900mm. The existing production process can produce a maximum width of about 1860mm while meeting the requirements of trimming. 963mm is the width of a conventional narrow-width aluminum foil cast coil for radiators. If a single-line production is used, the cast coil is split and trimmed to meet the needs of 933mm narrow-width orders for finished products. However, the single-line production efficiency is low, and the wide-width products produced by combining two lines to meet the requirements of trimming are planned to have a cast coil width of 1965mm, which exceeds the equipment capacity and will have The following control difficulties: ① The shape of the cast and rolled billet is difficult to control, which can easily cause abnormal shape of the finished product and affect the coating effect; ② The wide-width cast and rolled coil process has large cracks. During the cold rolling production process, under the dual effects of tension and pressure, the cracks continue to expand. The original large cracks will reach a certain extent under cold rolling and will cause the strip to break, or cannot be completely cut off during the trimming pass, affecting subsequent processing, increasing the amount of process trimming, reducing the product yield, and increasing production costs; ③ The width is large, the single-furnace production cycle is short, and the smelting process is difficult to guarantee; ④ Conventional radiator aluminum foil is produced in 8 passes, the production cycle time is relatively long, and the equipment processing rate is not fully utilized.

[0004] In the production of conventional aluminum foil for radiators, the maximum proportion of electrolytic aluminum liquid produced by casting and rolling is about 80%, which can meet the quality requirements. However, due to the limitations of on-site conditions, the metal impurities and alumina in the electrolytic aluminum liquid are much greater than those in the remelting of aluminum ingots, and it contains carbon, carbides, CaF2, NaF2, etc. produced by electrolysis. The electrolytic aluminum temperature is generally 920-950℃, the hydrogen content level is relatively high, and the melt has few crystallization cores. The aluminum liquid ratio of the radiator aluminum foil produced by the smelting furnace has been maintained at about 70%. The natural gas consumption per melt of 70% aluminum liquid ratio is 11.2-13.68kg / ton. The melting time of the solid material in the later stage is long, the amount of nitrogen oxides produced is large, and the pollution is serious. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for manufacturing oversized aluminum foil for radiators, in which the width of the sheet material satisfies the width of two sheets combined into one and the trimming amount, thereby improving the production efficiency of wide-width rolling mills, reducing energy consumption and ensuring product quality.

[0006] The technical solution adopted by the present invention is:

[0007] A method for manufacturing an oversized aluminum foil for a radiator, comprising the following specific steps:

[0008] S1: smelting;

[0009] Add solid materials and electrolytic aluminum liquid into the smelting furnace, with solid materials accounting for 5%-15% and electrolytic aluminum liquid accounting for 85%-95%;

[0010] The furnace is stewed without ignition to make use of the high temperature of the electrolytic aluminum liquid to melt the solid materials in the furnace and the temperature is not less than 720℃; after slagging, a refining agent is used for powder spraying refining, and the refining time is not less than the powder spraying time;

[0011] Adjust the alloy composition in the furnace, the iron content is 0.15-0.35%, the silicon content is 0.04-0.15%, the manganese content is 0.1-0.25%, the titanium content is 0.02-0.06%, the copper content is ≤0.02%, the magnesium content is ≤0.01%, and the zinc content is ≤0.02%; the single content of other impurities is ≤0.02%, and the total content of impurities is ≤0.1%;

[0012] After the composition is adjusted to meet the requirements, the aluminum liquid is fully purified through inert gas refining, heated and controlled to a refining temperature within the range of 745-755°C, and poured into a holding furnace. The holding furnace uses nitrogen refining. During the production process, the aluminum liquid is refined once every 4 hours. The rotary air blowing method is used for online degassing and slag removal. The slag is cleaned regularly, and the aluminum liquid is filtered in two stages through a filter box to ensure the quality of the melt.

[0013] S2: Casting and rolling;

[0014] The width of the casting nozzle is 8-10 mm less than the width of the billet plate. The gap of the distribution block in the casting nozzle increases by 5 mm from the middle to the edge. The opening of the upper and lower nozzles of the casting nozzle is 9.5-10 mm. The gap of the casting roller is preset to 5.0 mm, the prestress is 400KN, the casting and rolling area is 52-62 mm, and soft ears are used. The ear chamfer is U-shaped; the casting and rolling temperature is 693±3℃, the casting and rolling speed is 0.9-1.2m / min, the thickness of the cast slab is 6.7±0.2mm, the coiling tension is 55-70KN, and the cooling water pressure is 0.50-0.70Mpa; the convex value of the online plate shape control of the cast-rolled slab is -0.02-+0.01mm, the difference between two adjacent points is ≤0.03mm / 100mm, and the longitudinal thickness difference is ≤0.05mm; the appearance quality control of the cast-rolled slab: process crack edge ≤2mm, staggered layer ≤5mm, tower shape ≤10mm;

[0015] S3: rough rolling;

[0016] The slab with a thickness of 6.7±0.2 mm was rolled to a thickness of 1.0 mm in three passes, with the passes being 6.7±0.1-3.5-1.8-1.0;

[0017] One pass 6.7±0.2-3.5, entrance tensile stress 8±2N / mm 2 , outlet tension 16±2N / mm 2 , rolling speed ≤ 390mpm;

[0018] Second pass 3.5-1.8, entrance tensile stress 12±1N / mm 2 , outlet tension 19±1N / mm 2 , rolling speed ≤ 390mpm;

[0019] Three passes 1.8-1.0, entrance tensile stress 14±1N / mm 2 , outlet tension 22±1N / mm 2 , rolling speed ≤ 600mpm;

[0020] S4: cut edge and strip;

[0021] The slab rolled to 1.0 mm is transferred to the re-coiler for strip cutting and edge trimming. The coiling tension is 18-40KN, the disc knife gap is 0.056-0.08mm, the disc knife overlap is 0.034-0.058mm, and the edge trimming speed is 30-120 m / min.

[0022] S5: finishing rolling;

[0023] The 1.0 mm thick sheet after edge cutting is rolled to the finished product thickness in 4 passes, the passes are 1.0-0.48-0.28-0.16 / 0.165-finished product 0.095;

[0024] One pass 1.0-0.48, entrance tensile stress 20±1N / mm 2 , outlet tension 26±1N / mm 2 , rolling speed ≤ 650mpm;

[0025] Second pass 0.48-0.28, entrance tensile stress 25±1N / mm 2 , outlet tension 30±3N / mm 2 , rolling speed ≤750mpm;

[0026] Three passes 0.28-0.16 / 0.165, entrance tensile stress 30±3N / mm 2 , outlet tension 35±3N / mm 2, rolling speed ≤810mpm

[0027] Four passes 0.16 / 0.165-0.095, entrance tensile stress 40±3N / mm 2 , outlet tension 36±3N / mm 2 , rolling speed ≤810mpm;

[0028] S6: annealing;

[0029] The furnace is controlled at negative pressure. First, the temperature inside the furnace is raised to 220±3℃ in 1 hour and kept warm for 2 hours; then the temperature inside the furnace is raised to 290±3℃ in 2 hours and kept warm for 11 hours; at 275±3℃, the furnace is adjusted to positive pressure and kept warm for 16 hours.

[0030] Specifically, when a refining agent is used for powder spray refining in S1, the amount of the refining agent added is 1.8 kg / ton of aluminum; and the mesh number of the filter sheet of the double-stage filtration in the filter box is 30 meshes + 50 meshes.

[0031] Specifically, the solid material is trimmings and scraps and / or compressed blocks.

[0032] Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages:

[0033] The manufacturing method of the super-standard aluminum foil for radiators of the present invention increases the proportion of electrolytic aluminum liquid, reduces the proportion of solid materials, adopts the stewing method, reduces energy consumption and burning loss, saves energy and reduces emissions, and reduces production costs; adjusts the alloy component ratio and refining type additives in the furnace, adopts nitrogen blowing, effectively removes oxides and impurities in the aluminum liquid to ensure the purification effect, and ensures the continuity of high electrolytic aluminum liquid ratio production. Adjust the layout of the diverter block in the casting nozzle, adopt U-shaped chamfered soft ears, optimize the casting and rolling area and rolling process, and provide guarantees for increasing the width of the casting coil and reducing the amount of trimming; by controlling the rolling tension and the plate control, avoid the edge from being easily warped due to poor cooling of the edge; reduce the number of production passes, shorten the production time, and improve the production efficiency of the wide-width rolling mill. DETAILED DESCRIPTION

[0034] The present invention will be further explained below in conjunction with the embodiments, which are not intended to limit the protection scope 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

[0035] A method for manufacturing an oversized aluminum foil for a radiator, comprising the following specific steps:

[0036] S1: smelting;

[0037] Solid materials and electrolytic aluminum liquid are added to the smelting furnace, including trimmings or pressed blocks, with solid materials accounting for 10% and electrolytic aluminum liquid accounting for 90%. The temperature of the solid materials in the furnace is raised to no less than 720°C by stewing the furnace without ignition. According to the law of conservation of heat, during the stewing process, the solid materials absorb heat and the temperature rises. When the melting point is reached, the solid materials begin to melt. The heat required for this process is: Q=m[c1(t1-t0)+L+c2(t2-t1)]

[0038] Where c1——solid specific heat capacity, 1.138kJ / (kg*K)

[0039] c2——Specific heat capacity of liquid, 1.046kJ / (kg*K)

[0040] L——Latent heat of fusion, 393.56 kJ / kg

[0041] m——Mass of melt (Kg)

[0042] t0——Original melt temperature

[0043] t1——Melting point of the melt

[0044] t2——final temperature of the melt

[0045] Calculated based on 90% liquid volume, the temperature of the aluminum liquid injected into the smelting furnace by the electrolytic cell is calculated as 860°C, and the heat required to melt the solid material to 740°C is:

[0046] 100*【1.138*(660-40)+393.56+1.046*(740-660)】=118280kJ

[0047] The heat released by aluminum liquid is:

[0048] 900*1.046*(860-740)=112968

[0049] 100——(mass of solid melt Kg)

[0050] 900——Mass of electrolytic aluminum liquid Kg

[0051] From the above calculations, it can be seen that by using the stewing furnace without heating, the heat released by the aluminum liquid can meet the heat required for the solid material to melt to 740 degrees Celsius. The addition of a small amount of solid material can effectively reduce the temperature of the aluminum liquid on the one hand, and quickly form an effective crystallization core on the other hand.

[0052] After slagging, use refining agent for powder spraying refining. The amount of refining agent added is 1.8kg / ton aluminum, and the refining time is not less than the powder spraying time;

[0053] Adjust the alloy composition in the furnace, the iron content is 0.15-0.35%, the silicon content is 0.04-0.15%, the manganese content is 0.1-0.25%, the titanium content is 0.02-0.06%, the copper content is ≤0.02%, the magnesium content is ≤0.01%, and the zinc content is ≤0.02%; the single content of other impurities is ≤0.02%, and the total impurity content is ≤0.1%; the iron-silicon ratio is controlled at 2.45-4.00, and the titanium content is 0.02-0.06%, which can significantly improve the edge cracking, control the process cracking to ≤2mm, and reduce the amount of cold rolling trimming.

[0054] After the composition is adjusted to meet the requirements, the aluminum liquid is fully purified through inert gas refining, and briefly heated to control the refining temperature within the range of 745-755℃, and then poured into the holding furnace. The holding furnace uses nitrogen refining. During the production process, the liquid is refined once every 4 hours, and the rotary air blowing method is used for online degassing and slag removal. The slag is cleaned regularly, and the liquid is filtered through a double-stage filter box. The filter mesh number of the double-stage filter box is 30 mesh + 50 mesh to ensure the quality of the melt.

[0055] During the short heating of refining, the exhaust gas temperature and nitrogen oxide test data of three test points with an ignition time of less than 20 minutes are as follows:

[0056] Test 1: exhaust temperature 173℃, oxygen content 9.5%, nitrogen oxide conversion 436mg / m³;

[0057] Test 2: exhaust temperature 223℃, oxygen content 0%, nitrogen oxide conversion 363mg / m³;

[0058] Test 3: exhaust temperature 205℃, oxygen content 4.2%, nitrogen oxide conversion 785mg / m³;

[0059] The exhaust gas temperature and nitrogen oxide test data of the two test points after ignition for 2 hours are as follows:

[0060] Test 4: exhaust temperature 269°C, oxygen content 1.57%, nitrogen oxide conversion 1294mg / m³;

[0061] Test 5: exhaust temperature 264°C, oxygen content 5.4%, nitrogen oxide conversion 1657mg / m³;

[0062] The above data show that the ignition time is short, the exhaust temperature is low, and the nitrogen oxides are significantly smaller; and the natural gas consumption per melt with a 90% aluminum liquid ratio is 2.1-3.0 cubic meters / ton, compared with the natural gas consumption per melt with a 70% aluminum liquid ratio of 11.2-13.68kg / ton, the natural gas consumption per melt is reduced by 10m³ / ton, and the generation of nitrogen oxides is greatly reduced; the shortening of the melting process increases the melt purification time, making the melt purification more effective, and shortening the production time of a single melt to meet the needs of large-flow rolling production.

[0063] S2: Casting and rolling;

[0064] The width of the casting nozzle is 1946 mm, and the distribution gap of the diverter block in the casting nozzle increases by 5 mm from the middle to the edge, which are: 20mm, 25mm, 30mm, and 35mm, respectively, to avoid the color difference of the plate surface caused by poor air outlet when the wide cast-rolled plate is standing upright; the opening degree of the upper and lower nozzle pieces of the casting nozzle is 9.5-10mm; the gap between the casting and rolling rollers is preset to 5.0mm, the prestress is 400KN, the casting and rolling area is 52-62mm, and soft ears are used. The ear chamfer is U-shaped. The optimization of the ear chamfer, combined with the alloy composition, ensures that the crack edge is controlled at <2mm.

[0065] The casting and rolling temperature is 693±3℃, the casting and rolling speed is 0.9-1.2m / min, the thickness of the cast slab is 6.7±0.2mm, the coiling tension is 55-70KN, and the cooling water pressure is 0.50-0.70Mpa; a modifier of 1.7kg / ton aluminum is added to the chute, and the modifier uses domestic grade aluminum titanium boron wire.

[0066] The convex value of the cast-rolled slab online shape control is -0.02-+0.01mm, the difference between two adjacent points is ≤0.03mm / 100mm, and the longitudinal thickness difference is ≤0.05mm; the appearance quality control of the cast-rolled slab: process crack edge ≤2mm, staggered layer ≤5mm, tower shape ≤10mm; no defects such as hot zone, airway, hole, bubble, crack, flash, missing edge, sticky aluminum, metal or non-metallic inclusions are allowed; the surface is not allowed to have cast-rolled stripes, visible intermediate segregation and surface segregation: no corrosion, loose layer, bruise or roll-up is allowed, no black spots with a diameter of ≥3mm are allowed, and the plate surface is not allowed to have dark black and uneven oxide scale pressed into it; the casting and rolling process parameters are reasonably controlled, the shape requirements of the cast-rolled plate are controlled, and the normal process trimming amount of the conventional finished product 933mm specification is met. Under the premise, the cast-rolled coil specification width of 1955mm can be produced. Compared with the 1965mm width air-conditioning foil in the process plan, the cooling intensity is improved and the process trimming amount is reduced by 10mm.

[0067] S3: rough rolling;

[0068] The slab with a thickness of 6.7±0.2 mm was rolled to a thickness of 1.0 mm in three passes, with the passes being 6.7±0.2-3.5-1.8-1.0;

[0069] One pass 6.7±0.2-3.5, entrance tensile stress 8±2N / mm 2 , outlet tension 16±2N / mm 2 , rolling speed ≤ 390mpm;

[0070] Second pass 3.5-1.8, entrance tensile stress 12±1N / mm 2 , outlet tension 19±1N / mm 2, rolling speed ≤ 390mpm;

[0071] Three passes 1.8-1.0, entrance tensile stress 14±1N / mm 2 , outlet tension 22±1N / mm 2 , rolling speed ≤600mpm.

[0072] S4: cut edge and strip;

[0073] The slab rolled to 1.0mm is transferred to the recoiler for strip splitting and trimming. The curling tension is 18-40KN, the disc knife gap is 0.056-0.08mm, the disc knife overlap is 0.034-0.058mm, and the trimming speed is 30-120 m / min.

[0074] S5: finishing rolling;

[0075] The 1.0 mm thick slab after edge cutting is rolled in 4 passes to a finished product thickness of 0.095 mm, and the passes are 1.0-0.48-0.28-0.16 / 0.165-finished product 0.095;

[0076] One pass 1.0-0.48, entrance tensile stress 20±1N / mm 2 , outlet tension 26±1N / mm 2 , rolling speed ≤ 650mpm;

[0077] Second pass 0.48-0.28, entrance tensile stress 25±1N / mm 2 , outlet tension 30±3N / mm 2 , rolling speed ≤750mpm;

[0078] Three passes 0.28-0.16 / 0.165, entrance tensile stress 30±3N / mm 2 , outlet tension 35±3N / mm 2 , rolling speed ≤810mpm

[0079] Four passes 0.16 / 0.165-0.095, entrance tensile stress 40±3N / mm 2 , outlet tension 36±3N / mm 2 , rolling speed ≤810mpm.

[0080] S6: annealing;

[0081] During annealing of finished products, check the quality of the end faces of incoming materials, check whether the end caps are firmly sealed with high-temperature tape, check whether there is aluminum foil on the circulating fan cover of the furnace and clean it; the furnace is controlled to be under negative pressure, first raise the temperature to 220±3℃ in 1h and keep it warm for 2h; then raise the temperature to 290±3℃ in 2h and keep it warm for 11h; at 275±3℃, adjust the furnace to positive pressure and keep it warm for 16h.

[0082] Parts of the present invention not described in detail are prior art.

[0083] The embodiments selected herein for the purpose of disclosing the invention are currently considered to be suitable, but it should be understood that the invention is intended to include all changes and modifications of the embodiments that fall within the scope of the concept and invention.

Claims

1. A method for manufacturing ultra-wide aluminum foil for radiator, characterized in that: The specific steps include: S1: smelting; Solid materials and electrolytic aluminum liquid are added to the smelting furnace, with solid materials accounting for 5%, and solid materials are trimmings and / or pressed blocks; electrolytic aluminum liquid accounts for 95%; the furnace is stewed without ignition to utilize the high temperature of electrolytic aluminum liquid to melt the solid materials in the furnace and the temperature is not less than 720°C; after slagging, refining agent is used for powder spraying refining, and the amount of refining agent added is 1.8kg / ton aluminum; the refining time is not less than the powder spraying time; Adjust the alloy composition in the furnace, the iron content is 0.15-0.35%, the silicon content is 0.04-0.15%, the manganese content is 0.1-0.25%, the titanium content is 0.02-0.06%, the copper content is ≤0.02%, the magnesium content is ≤0.01%, and the zinc content is ≤0.02%; the single content of other impurities is ≤0.02%, and the total content of impurities is ≤0.1%; After the composition is adjusted to meet the requirements, the aluminum liquid is fully purified through inert gas refining, heated and controlled to a refining temperature within the range of 745-755°C, and poured into a holding furnace. The holding furnace uses nitrogen refining. During the production process, the aluminum liquid is refined once every 4 hours. The rotary air blowing method is used for online degassing and slag removal. The slag is cleaned regularly and filtered through a double-stage filter box. The filter sheet mesh number of the double-stage filter box is 30 mesh + 50 mesh to ensure the quality of the melt. S2: Casting and rolling; The width of the casting nozzle is 8-10mm less than the width of the billet plate. The gap of the diverter block in the casting nozzle increases by 5mm from the middle to the edge. The opening of the upper and lower nozzles of the casting nozzle is 9.5-10mm. The gap between the casting and rolling rollers is preset to be 5.0mm, the prestress is 400KN, the casting and rolling area is 52-62mm, and soft ears are used. The ear chamfer is U-shaped. The casting and rolling temperature is 693±3℃, the casting and rolling speed is 0.9-1.2m / min, the thickness of the cast slab is 6.7±0.2mm, the coiling tension is 55-70KN, and the cooling water pressure is 0.50-0.70Mpa. The convex value of the online plate shape control of the cast and rolling slab is -0.02-+0.01mm, the difference between two adjacent points is ≤0.03mm / 100mm, and the longitudinal thickness difference is ≤0.05mm. Appearance quality control of cast and rolled slab: process crack edge ≤2mm, staggered layer ≤5mm, tower shape ≤10mm; S3: rough rolling; The slab of 6.7±0.2 mm was rolled to 1.0 mm thickness in 3 passes, the passes were 6.7±0.2-3.5-1.8-1.0; One pass 6.7±0.2-3.5, entrance tensile stress 8±2N / mm 2 , outlet tension 16±2N / mm 2 , rolling speed ≤ 390mpm; Second pass 3.5-1.8, entrance tensile stress 12±1N / mm 2 , outlet tension 19±1N / mm 2 , rolling speed ≤ 390mpm; Three passes 1.8-1.0, entrance tensile stress 14±1N / mm 2 , outlet tension 22±1N / mm 2 , rolling speed ≤ 600mpm; S4: cut edge and strip; The slab rolled to 1.0mm is transferred to the re-coiler for strip cutting and edge trimming. The curling tension is 18-40KN, the disc knife gap is 0.056-0.08mm, the disc knife overlap is 0.034-0.058mm, and the edge trimming speed is 30-120m / min. S5: finishing rolling; The 1.0 mm thick sheet after edge cutting is rolled in 4 passes to the finished product thickness, the passes are 1.0-0.48-0.28-0.16 / 0.165-finished product 0.095; One pass 1.0-0.48, entrance tensile stress 20±1N / mm 2 , outlet tension 26±1N / mm 2 , rolling speed ≤ 650mpm; Second pass 0.48-0.28, entrance tensile stress 25±1N / mm 2 , outlet tension 30±3N / mm 2 , rolling speed ≤750mpm; Three passes 0.28-0.16 / 0.165, entrance tensile stress 30±3N / mm 2 , outlet tension 35±3N / mm 2 , rolling speed ≤810mpm; Four passes 0.16 / 0.165-0.095, entrance tensile stress 40±3N / mm 2 , outlet tension 36±3N / mm 2 , rolling speed ≤810mpm; S6: annealing; The furnace is controlled at negative pressure. First, the temperature inside the furnace is raised to 220±3℃ in 1 hour and kept warm for 2 hours; then the temperature inside the furnace is raised to 290±3℃ in 2 hours and kept warm for 11 hours; at 275±3℃, the furnace is adjusted to positive pressure and kept warm for 16 hours.