Preparation method of high-elongation cast-rolling 3003 aluminum alloy plate strip

Abstract

The invention discloses a preparation method of a high-elongation cast-rolled 3003 aluminum alloy plate strip. The 3003 aluminum alloy plate strip with the thickness being 0.20-0.30 mm and the elongation being larger than or equal to 35% is obtained after alloy blending, cast-rolled blank production, cast-rolled blank high-temperature pre-annealing treatment, first recrystallization annealing, second recrystallization annealing and finished product annealing. According to the method, process improvement is carried out on the basis of a conventional cast-rolling method, a 3003 aluminum alloy plate strip finished product is produced through the method of shortening the length of a cast-rolling area, reducing the cast-rolling speed and increasing the thickness of a cast-rolling plate, high-temperature preheating annealing treatment is combined with cast-rolling blank, first recrystallization annealing treatment and second recrystallization annealing treatment are carried out on the first two passes of cold rolling, and the finished product is obtained. And finally, the 3003 aluminum alloy plate strip meeting the requirement for pipeline materials is obtained through cold rolling, the purposes of simplifying the production process, saving energy and reducing cost are achieved, the range of target products of existing cast rolling equipment is widened, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy production, and in particular to a method for preparing a high-elongation cast-rolled 3003 aluminum alloy plate and strip. Background Art

[0002] Aluminum is a silvery white metal with a melting point of 660°C and a density of 2.7 g / cm 3 , has good corrosion resistance, electrical conductivity and thermal conductivity, high specific strength, good ductility and plasticity, and is easy to process and shape. However, due to the low strength of pure aluminum, it is necessary to add alloy elements to strengthen it and make it into aluminum alloy products before it can be used in aerospace, transportation, construction, packaging and other fields. 3003 aluminum alloy is an Al-Mn aluminum alloy with good rust resistance, formability, weldability and corrosion resistance. Because its mechanical properties are significantly better than conventional 1 series alloy aluminum products, it is often used to make parts used in humid environments, such as tanks for transporting liquid products, various pressure vessels and pipelines.

[0003] 3003 aluminum alloy strips with a thickness of 0.20-0.30 mm are mainly used to make pipe products with large deformation, and their elongation is required to be ≥35%. At present, the production of 3003 aluminum alloy strips with a thickness of 0.20-0.30 mm usually adopts conventional casting and rolling method (casting-cold rolling) or hot rolling method (ingot-hot rolling-cold rolling). Among them, the conventional casting and rolling method is a metal casting and rolling method that continuously passes liquid aluminum through rotating rollers (crystallizer) to form a blank and then rolls it into a strip. The hot rolling method is a metal processing process that heats the metal blank to a high temperature and then rolls it. The two methods will encounter the following problems during the production process: (1) The elongation of 3003 aluminum alloy strips produced by conventional casting and rolling It is only 20%, which cannot meet the requirement of elongation ≥35% for pipe plates; (2) When the conventional casting and rolling method is used, the cooling speed is faster than that of the traditional deep well casting. Most of the manganese atoms have no time to diffuse, and a highly supersaturated aluminum matrix will be obtained. The aluminum matrix will precipitate in large quantities during the recrystallization annealing process after cold rolling, resulting in coarse and uneven recrystallization structure; (3) When the hot rolling method is used, it is necessary to carry out smelting, deep well casting of ingots, ingot washing, homogenization annealing, hot rolling, cold rolling, annealing and other treatments, which has the disadvantages of many production processes, long process cycle and high production cost. Compared with the hot rolling method, the conventional casting and rolling method consumes less energy and can save about 40% of energy. It has the advantages of small equipment investment, short production cycle, and is conducive to recycling waste and low transportation costs. It can partially or completely save the hot rolling process with large investment and heavy equipment, thereby simplifying the production process and reducing costs. Summary of the invention

[0004] The invention provides a method for preparing a high-elongation cast-rolled 3003 aluminum alloy plate and strip, the purpose of which is to improve the conventional casting and rolling method, simplify the process, reduce the cost, and prepare a 3003 aluminum alloy plate and strip for pipes with a thickness of 0.20-0.30 mm and an elongation of ≥35%.

[0005] To achieve its purpose, the present invention adopts the following technical solutions: A method for preparing a high-elongation cast-rolled 3003 aluminum alloy strip comprises the following steps: S1: alloy preparation; smelting aluminum ingots to obtain aluminum liquid, adding master alloys and stirring when the aluminum liquid temperature is 730-760°C, and degassing and refining to obtain 3003 aluminum alloy melt; the master alloy composition is calculated by weight percentage: Si≤0.20%, Fe: 0.40-0.60%, Cu: 0.12-0.15%, Mn: 1.00-1.20%, and the rest is Al; S2: producing a cast-rolled billet; the 3003 aluminum alloy melt obtained in step S1 is cast-rolled to obtain a cast-rolled billet with a thickness of 10-12 mm; the length of the casting zone is 40-50 mm, and the casting strip speed is 500-700 mm / min; S3: high temperature pre-annealing of the cast-rolled billet; the cast-rolled billet obtained in step S2 is sent to an annealing furnace for pre-annealing, and after the temperature of the cast-rolled billet reaches 570-600°C, it is kept warm for 5-7h and taken out of the furnace to obtain a pre-annealed cast-rolled billet; S4: first recrystallization annealing; the pre-annealed cast-rolled billet obtained in step S3 is cold-rolled from 10-12mm to 7-8mm to obtain a primary cold-rolled coil, and the primary cold-rolled coil is unrolled and sent to an annealing furnace for the first recrystallization annealing, and after the temperature of the primary cold-rolled coil reaches 550-580°C, it is kept warm for 4-6h and taken out of the furnace to obtain a cold-rolled coil after the first recrystallization annealing; S5: Second recrystallization annealing: The cold rolled coil obtained in step S4 with a thickness of 7-8 mm after the first recrystallization annealing is subjected to a second cold rolling to a thickness of 3.5-4.5 mm to obtain a second cold rolled coil. The second cold rolled coil is unrolled and sent to an annealing furnace for a second recrystallization annealing. After the temperature of the second cold rolled coil reaches 500-530° C., it is kept warm for 4-6 hours and then taken out of the furnace to obtain a cold rolled coil after the second recrystallization annealing. S6: annealing of finished product; the cold rolled coil after the second recrystallization annealing obtained in step S5 is cold rolled to 0.20-0.30 mm for several passes to obtain a finished cold rolled coil, and the finished cold rolled coil is unloaded and sent to an annealing furnace for finished product annealing. After the temperature of the finished cold rolled coil reaches 350-400°C, it is kept warm for 3-5 hours and taken out of the furnace. After cooling, a 3003 aluminum alloy plate with a thickness of 0.20-0.30 mm and an elongation of ≥35% is obtained.

[0006] Furthermore, a smelting furnace is used for smelting the aluminum ingot in step S1.

[0007] Furthermore, the time for degassing and refining in step S1 is 30-40 minutes.

[0008] Furthermore, in step S2, a casting and rolling mill is used for casting and rolling the 3003 aluminum alloy melt.

[0009] Furthermore, the gap between the casting rolls of the casting mill is 10-11 mm, the roughness of the casting rolls is 1.03 μm, and the convexity is 0.62.

[0010] Furthermore, in steps S3, S4, S5 and S6, the furnace gas temperature of the annealing furnace is 490-620°C.

[0011] Furthermore, a cold rolling mill is used in the cold rolling of steps S4, S5 and S6.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. The method improves the process on the basis of the conventional casting and rolling method, specifically, the length of the casting and rolling zone is shortened from 55-65mm to 40-50mm, the casting and rolling speed is reduced from 800-900 mm / min to 500-700mm / min, the thickness of the cast-rolled plate is increased from 6-7mm to 10-12mm, the casting and rolling cooling rate is reduced, and the high-temperature pre-annealing treatment of the cast-rolled billet is combined, and the first recrystallization annealing and the second recrystallization annealing are respectively performed in the first two passes of cold rolling. Finally, the 3003 aluminum alloy plate and strip with a target thickness of 0.20-0.30mm and an elongation of ≥35% is obtained by cold rolling. The limitation problem that only the hot rolling method (ingot-hot rolling-cold rolling) can produce 3003 aluminum alloy plates and strips that meet the requirements is solved. Compared with the hot rolling method, the purpose of simplifying the production process, saving energy and reducing costs is achieved, the range of target products of existing casting and rolling equipment is broadened, and the production efficiency is improved.

[0013] 2. This method reduces the supersaturation of manganese atoms by shortening the length of the casting and rolling zone (the area where the aluminum melt is poured to the rolling center line), reducing the casting and rolling speed and cooling speed, and then treats the cast and rolled billet through high-temperature pre-annealing to promote the precipitation of supersaturated solid solution manganese atoms, so as to reduce the precipitation of manganese atoms in the subsequent recrystallization annealing process, thereby solving the problem of coarse and uneven recrystallization structure. After the cast and rolled billet is cold rolled, it undergoes multiple recrystallization annealing and refinement treatment, thereby improving the elongation of 3003 aluminum alloy plate and strip products. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a physical picture of the finished 3003 aluminum alloy plate and strip in Example 1 of the present invention. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with embodiments: In the following embodiments of the present invention, the smelting furnace is a 25t smelting furnace, the casting and rolling mill is a 1900mm inclined casting and rolling mill, the annealing furnace is a 40t high temperature annealing furnace, and the cold rolling mill is a 1850mm cold rolling mill.

[0016] Example 1 The present invention is a method for preparing a high-elongation cast-rolled 3003 aluminum alloy strip, comprising the following steps: S1: alloy preparation; the aluminum ingot is sent into a smelting furnace to obtain aluminum liquid, and when the temperature of the aluminum liquid reaches 750°C, the master alloy is added, and electromagnetic stirring is performed for 30 minutes. After the master alloy is completely melted and uniformly dissolved in the aluminum liquid, degassing and refining is performed for 30 minutes to obtain a 3003 aluminum alloy melt; the composition of the master alloy is Si: 0.12%, Fe: 0.56%, Cu: 0.14%, Mn: 1.15%, and the rest is Al in percentage by weight; S2: producing a cast-rolled billet; feeding the 3003 aluminum alloy melt obtained in step S1 into a casting and rolling mill for casting and rolling to obtain a cast-rolled billet with a thickness of 12 mm; the casting roll gap of the casting and rolling mill is 10.8 mm, when the casting nozzle is installed, the casting and rolling zone length is 43 mm, the casting and rolling strip speed is 580 mm / min, the casting roll roughness is 1.03 μm, and the convexity is 0.62; S3: high temperature pre-annealing of the cast-rolled billet; the 12 mm cast-rolled billet obtained in step S2 is sent to an annealing furnace with a furnace gas temperature of 620°C for pre-annealing. After the temperature of the cast-rolled billet reaches 590°C, it is kept warm for 6 hours and then taken out of the furnace to obtain a pre-annealed cast-rolled billet; S4: first recrystallization annealing; cold rolling the pre-annealed cast-rolled billet obtained in step S3 from 12 mm to 8 mm to obtain a first cold-rolled coil, and then unrolling the first cold-rolled coil and sending it into an annealing furnace with a furnace gas temperature of 620° C. for the first recrystallization annealing. After the temperature of the first cold-rolled coil reaches 560° C., it is kept warm for 5 hours and then taken out of the furnace to obtain a cold-rolled coil with a thickness of 8 mm after the first recrystallization annealing; S5: Second recrystallization annealing: The cold rolled coil with a thickness of 8 mm obtained in step S4 after the first recrystallization annealing is secondarily cold rolled to 4.5 mm to obtain a second cold rolled coil, and then the second cold rolled coil is unloaded and sent to an annealing furnace with a furnace gas temperature of 590° C. for second recrystallization annealing. After the temperature of the second cold rolled coil reaches 530° C., it is kept warm for 5 hours and then taken out of the furnace to obtain a second recrystallization annealed cold rolled coil with a thickness of 4.5 mm; S6: Finished product annealing; the cold rolled coil with a thickness of 4.5 mm obtained in step S5 after the second recrystallization annealing is subjected to multiple cold rolling as shown in Table 1 to obtain a finished cold rolled coil with a thickness of 0.30 mm, and then the finished cold rolled coil is unloaded and sent to an annealing furnace with a furnace gas temperature of 490°C for finished product annealing. After the finished cold rolled coil temperature reaches 390°C, it is kept warm for 5 hours and taken out of the furnace, and then cooled to obtain Figure 1 As shown, the finished product of 3003 aluminum alloy strip with a thickness of 0.30 mm; S7: The finished 3003 aluminum alloy strip with a thickness of 0.30 mm obtained in step S6 is sampled and subjected to a tensile test. The test results are shown in Table 2.

[0017] Example 2 The present invention is a method for preparing a high-elongation cast-rolled 3003 aluminum alloy strip, comprising the following steps: S1: alloy preparation; the aluminum ingot is sent into a smelting furnace to obtain aluminum liquid, and when the temperature of the aluminum liquid reaches 730°C, the master alloy is added, and electromagnetic stirring is performed for 30 minutes. After the master alloy is completely melted and uniformly dissolved in the aluminum liquid, degassing and refining is performed for 36 minutes to obtain a 3003 aluminum alloy melt; the composition of the master alloy is Si: 0.20%, Fe: 0.40%, Cu: 0.12%, Mn: 1.20%, and the rest is Al in percentage by weight; S2: producing a cast billet; feeding the 3003 aluminum alloy melt obtained in step S1 into a casting mill for casting and rolling to obtain a cast billet with a thickness of 11.4 mm; the casting roll gap of the casting mill is 10.2 mm, when the casting nozzle is installed, the casting zone length is 40 mm, the casting strip speed is 500 mm / min, the casting roll roughness is 1.03 μm, and the convexity is 0.62; S3: high temperature pre-annealing of the cast-rolled billet; the 11.4 mm cast-rolled billet obtained in step S2 is sent to an annealing furnace with a furnace gas temperature of 620°C for pre-annealing. After the temperature of the cast-rolled billet reaches 570°C, it is kept warm for 5 hours and then taken out of the furnace to obtain a pre-annealed cast-rolled billet; S4: first recrystallization annealing; the pre-annealed cast-rolled billet obtained in step S3 is cold-rolled from 11.4 mm to 7.5 mm to obtain a first cold-rolled coil, and then the first cold-rolled coil is unloaded and sent to an annealing furnace with a furnace gas temperature of 620° C. for the first recrystallization annealing. After the temperature of the first cold-rolled coil reaches 550° C., it is kept warm for 4 hours and taken out of the furnace to obtain a cold-rolled coil with a thickness of 7.5 mm after the first recrystallization annealing; S5: Second recrystallization annealing: The cold rolled coil with a thickness of 7.5 mm obtained in step S4 after the first recrystallization annealing is secondarily cold rolled to 4.0 mm to obtain a second cold rolled coil, and then the second cold rolled coil is unloaded and sent to an annealing furnace with a furnace gas temperature of 590° C. for second recrystallization annealing. After the temperature of the second cold rolled coil reaches 500° C., it is kept warm for 4 hours and taken out of the furnace to obtain a second recrystallization annealed cold rolled coil with a thickness of 4.0 mm; S6: Finished product annealing; the cold rolled coil with a thickness of 4.0 mm obtained in step S5 after the second recrystallization annealing is subjected to multiple cold rolling as shown in Table 1 to obtain a finished cold rolled coil with a thickness of 0.25 mm, and then the finished cold rolled coil is unloaded and sent to an annealing furnace with a furnace gas temperature of 490°C for finished product annealing. After the finished cold rolled coil temperature reaches 350°C, it is kept warm for 3 hours and taken out of the furnace. After cooling, a finished 3003 aluminum alloy strip with a thickness of 0.25 mm is obtained; S7: The finished 3003 aluminum alloy strip with a thickness of 0.25 mm obtained in step S6 is sampled and subjected to a tensile test. The test results are shown in Table 2.

[0018] Example 3 The present invention is a method for preparing a high-elongation cast-rolled 3003 aluminum alloy strip, comprising the following steps: S1: alloy preparation; the aluminum ingot is sent into a smelting furnace to obtain aluminum liquid, and when the temperature of the aluminum liquid reaches 730°C, the master alloy is added, and electromagnetic stirring is performed for 30 minutes. After the master alloy is completely melted and uniformly dissolved in the aluminum liquid, degassing and refining is performed for 40 minutes to obtain a 3003 aluminum alloy melt; the composition of the master alloy is Si: 0.13%, Fe: 0.60%, Cu: 0.15%, Mn: 1.00%, and the rest is Al in percentage by weight; S2: producing a cast billet; feeding the 3003 aluminum alloy melt obtained in step S1 into a casting mill for casting and rolling to obtain a cast billet with a thickness of 10 mm; the casting roll gap of the casting mill is 11 mm, when the casting nozzle is installed, the casting zone length is 50 mm, the casting strip speed is 700 mm / min, the casting roll roughness is 1.03 μm, and the convexity is 0.62; S3: high temperature pre-annealing of the cast-rolled billet; the 10 mm cast-rolled billet obtained in step S2 is sent to an annealing furnace with a furnace gas temperature of 620°C for pre-annealing. After the temperature of the cast-rolled billet reaches 600°C, it is kept warm for 7 hours and then taken out of the furnace to obtain a pre-annealed cast-rolled billet; S4: first recrystallization annealing; the pre-annealed cast-rolled billet obtained in step S3 is cold-rolled from 10 mm to 7.0 mm to obtain a first cold-rolled coil, and then the first cold-rolled coil is unloaded and sent to an annealing furnace with a furnace gas temperature of 620° C. for the first recrystallization annealing. After the temperature of the first cold-rolled coil reaches 580° C., it is kept warm for 6 hours and taken out of the furnace to obtain a cold-rolled coil with a thickness of 7.0 mm after the first recrystallization annealing; S5: Second recrystallization annealing: The cold rolled coil with a thickness of 7.0 mm obtained in step S4 after the first recrystallization annealing is secondarily cold rolled to 3.5 mm to obtain a second cold rolled coil, and then the second cold rolled coil is unloaded and sent to an annealing furnace with a furnace gas temperature of 590° C. for second recrystallization annealing. After the temperature of the second cold rolled coil reaches 520° C., it is kept warm for 6 hours and then taken out of the furnace to obtain a second recrystallization annealed cold rolled coil with a thickness of 3.5 mm; S6: Finished product annealing; the cold rolled coil with a thickness of 3.5 mm obtained in step S5 after the second recrystallization annealing is subjected to multiple cold rolling as shown in Table 1 to obtain a finished cold rolled coil with a thickness of 0.20 mm, and then the finished cold rolled coil is unloaded and sent to an annealing furnace with a furnace gas temperature of 490°C for finished product annealing. After the finished cold rolled coil temperature reaches 400°C, it is kept warm for 3 hours and taken out of the furnace. After cooling, a finished 3003 aluminum alloy strip with a thickness of 0.20 mm is obtained; S7: The finished 3003 aluminum alloy strip with a thickness of 0.20 mm obtained in step S6 is sampled and subjected to a tensile test. The test results are shown in Table 2.

[0019] The thickness and processing rate of the multi-pass cold rolling in Examples 1-3 are shown in Table 1, and the tensile strength and elongation test results of the finished aluminum alloy strip are shown in Table 2: Table 1 Thickness and processing rate of multi-pass cold rolling Table 2 Tensile strength and elongation of aluminum alloy strip From the analysis of Table 1-2, it can be seen that the present invention produces 3003 aluminum alloy plate and strip finished products by shortening the length of the casting and rolling zone, reducing the casting and rolling speed, and increasing the thickness of the cast and rolled plate. Combined with the high-temperature preheating annealing treatment of the cast and rolled billet, the first two passes before cold rolling are respectively subjected to the first recrystallization annealing and the second recrystallization annealing. Finally, the target thickness of 0.20-0.30 mm and the elongation of 3003 aluminum alloy plate and strip finished products of ≥35% are obtained by cold rolling, which meets the demand for pipeline materials.

Claims

1. A method for preparing high elongation cast-rolled 3003 aluminum alloy strip, characterized in that: The following steps are involved: S1: alloy preparation; smelting aluminum ingots to obtain aluminum liquid, adding master alloys and stirring when the aluminum liquid temperature is 730-760°C, and degassing and refining to obtain 3003 aluminum alloy melt; the master alloy composition is calculated by weight percentage: Si≤0.20%, Fe: 0.40-0.60%, Cu: 0.12-0.15%, Mn: 1.00-1.20%, and the rest is Al; S2: producing a cast-rolled billet; the 3003 aluminum alloy melt obtained in step S1 is cast-rolled to obtain a cast-rolled billet with a thickness of 10-12 mm; the length of the casting zone is 40-50 mm, and the casting strip speed is 500-700 mm / min; S3: high temperature pre-annealing of the cast-rolled billet; sending the cast-rolled billet obtained in step S2 into an annealing furnace for pre-annealing, and after the temperature of the cast-rolled billet reaches 570-600°C, keeping it warm for 5-7h and taking it out of the furnace to obtain a pre-annealed cast-rolled billet; S4: first recrystallization annealing; cold rolling the pre-annealed cast-rolled billet obtained in step S3 from 10-12 mm to 7-8 mm to obtain a first cold-rolled coil, unrolling the first cold-rolled coil and sending it into an annealing furnace for the first recrystallization annealing, and after the temperature of the first cold-rolled coil reaches 550-580° C., heat preservation for 4-6 hours and then taking it out of the furnace to obtain a cold-rolled coil after the first recrystallization annealing; S5: Second recrystallization annealing: The cold rolled coil obtained in step S4 with a thickness of 7-8 mm after the first recrystallization annealing is subjected to a second cold rolling to a thickness of 3.5-4.5 mm to obtain a second cold rolled coil. The second cold rolled coil is unrolled and sent to an annealing furnace for a second recrystallization annealing. After the temperature of the second cold rolled coil reaches 500-530° C., it is kept warm for 4-6 hours and then taken out of the furnace to obtain a cold rolled coil after the second recrystallization annealing. S6: annealing of finished product; the cold rolled coil after the second recrystallization annealing obtained in step S5 is cold rolled to 0.20-0.30 mm for several passes to obtain a finished cold rolled coil, and the finished cold rolled coil is unloaded and sent to an annealing furnace for finished product annealing. After the temperature of the finished cold rolled coil reaches 350-400°C, it is kept warm for 3-5 hours and taken out of the furnace. After cooling, a 3003 aluminum alloy plate with a thickness of 0.20-0.30 mm and an elongation of ≥35% is obtained.

2. The method for preparing a high elongation cast-rolled 3003 aluminum alloy strip according to claim 1, characterized in that: In step S1, a smelting furnace is used for smelting the aluminum ingot.

3. The method for preparing a high elongation cast-rolled 3003 aluminum alloy strip as claimed in claim 2, characterized in that: The time for degassing and refining in step S1 is 30-40 minutes.

4. The method for preparing a high elongation cast-rolled 3003 aluminum alloy strip as claimed in claim 3, characterized in that: In step S2, a casting and rolling mill is used for casting and rolling of the 3003 aluminum alloy melt.

5. The method for preparing a high elongation cast-rolled 3003 aluminum alloy strip as claimed in claim 4, characterized in that: The casting roll gap of the casting rolling mill is 10-11 mm, the casting roll roughness is 1.03 μm, and the convexity is 0.

62.

6. The method for preparing a high elongation cast-rolled 3003 aluminum alloy strip as claimed in claim 5, characterized in that: The furnace gas temperature of the annealing furnace in steps S3, S4, S5 and S6 is 490-620°C.

7. The method for preparing a high elongation cast-rolled 3003 aluminum alloy strip as claimed in claim 6, characterized in that: The cold rolling in steps S4, S5 and S6 is performed using a cold rolling mill.

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