A method for producing an aluminum alloy cold-rolled coil

Abstract

The application discloses an aluminum alloy cold-rolled coil production method and relates to the technical field of aluminum alloy coil preparation. The specific production method comprises the following steps: S1, rolling: first, increase the width by obliquely rolling the cast ingot, and then perform longitudinal rolling to obtain an aluminum coil; S2, cleaning and splicing: splice 2-3 aluminum coils at a splicing device of a cleaning machine to form a spliced coil, and the pressure of the splicing device is 12-13 Mpa; S3, heat treatment: perform heat treatment on the coil after cleaning and splicing; S4, tension leveling: perform tension leveling and shearing on the coil after heat treatment, and the finished product is obtained. The application solves the problems of low production efficiency and low finished product rate of the aluminum alloy cold-rolled coil with a width greater than or equal to 2500 mm in subsequent heat treatment, can greatly reduce the width of the cast ingot, avoids the cast ingot from being scrapped due to cracks generated during casting, can also increase the weight of a single coil, reduce the equipment operation amount, reduce the generation of waste materials, and further improve the production efficiency, and is very beneficial to large-scale production.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy coil preparation technology, and in particular to a method for producing cold-rolled aluminum alloy coils. Background Technology

[0002] With the increasing demand for aluminum alloy coils, industry competition is becoming increasingly fierce. Aluminum processing companies are hoping to reduce production costs and improve market competitiveness by increasing production capacity per unit time and improving production efficiency. Currently, aluminum processing companies are using larger and wider equipment, and the width of their products is also increasing, requiring wider ingots. However, the wider the ingot, the more prone it is to cracking defects during the casting process.

[0003] In existing technologies, aluminum alloy coils with a width ≥ 2500 mm are produced using ingots with the following specifications: ingot width = finished product width - (100~800 mm), maximum ingot length = mill roll width - (150~200) mm, and ingot thickness = 500~650 mm. The width is increased to finished product width + (100~200) mm through transverse rolling of the ingot, followed by longitudinal rolling. The disadvantages of this technology are that the ingot length is limited by the mill width, resulting in a single coil weight of only 8-12 tons (the equipment is designed to produce single coils weighing 20-30 tons). Furthermore, subsequent heat treatment processes are inefficient, leading to a low yield. Patent CN 114774657 A discloses a method for preparing high-strength and tough thin 7-series aluminum alloy strip. This method involves mechanically stitching, threading, pre-cleaning, solution treatment, quenching, and pre-stretching 7-series aluminum alloy strips cold-rolled to a thickness of 0.10–0.50 mm in an air-cushion continuous annealing furnace, followed by box-type artificial aging annealing. However, using an air-cushion continuous annealing furnace results in high equipment and process costs, and is only applicable to strips of 0.1–0.5 mm thickness. Furthermore, the stitching operation is merely to thread the strip through the air-cushion continuous annealing furnace; the resulting coil size remains the original size.

[0004] Based on the above problems, the purpose of this application is to provide a method for producing cold-rolled aluminum alloy coils. Summary of the Invention

[0005] To address the above shortcomings, this invention provides a method for producing cold-rolled aluminum alloy coils, solving the problems of low production efficiency and low yield in subsequent heat treatment of cold-rolled aluminum alloy coils with a width ≥2500mm. The specific technical solution is as follows:

[0006] A method for producing cold-rolled aluminum alloy coils includes the following steps:

[0007] S1. Rolling: First, the ingot is rolled obliquely to increase its width, and then rolled longitudinally to obtain an aluminum coil;

[0008] The width of the ingot = finished product width - (200~1000) mm, the length of the ingot = mill roll surface width + (100~800) mm, and the thickness of the ingot = 500~650 mm;

[0009] S2. Cleaning and sewing: Place 2 to 3 aluminum coils on the sewing device of the cleaning machine and sew them together. The pressure of the sewing device is 12 to 13 MPa. If the sewing pressure is too low, the sewing will not be firm. If the sewing pressure is too high, the sewing will easily cause severe deformation at the sewing point. During annealing, the coil near the sewing head will be squeezed and deformed.

[0010] S3. Heat treatment: Heat treat the cleaned and sewn roll material;

[0011] S4. Straightening: The heat-treated roll material is straightened and cut using a straightening machine to obtain the finished product.

[0012] Furthermore, in step S1, during the oblique rolling of the ingot, the ingot head is positioned at an angle of 15 to 60 degrees to the roll.

[0013] Furthermore, in step S1, the thickness of the aluminum coil is 1 to 1.2 mm.

[0014] Furthermore, in step S2, the initial tensile stress of the cleaning machine is 14-18 MPa, and the tensile stress of the cleaning machine after sewing is set to 70-80% of the initial tensile stress. If the tension is too high, creases will appear at the sewing point, and if the tension is too low, the aluminum coil will not be tightly rolled and loose layers will appear.

[0015] Furthermore, in step S3, the heat treatment is carried out in a box furnace.

[0016] Furthermore, in step S3, the heat treatment temperature is 120–350°C.

[0017] Furthermore, in step S4, the unwinding stress of the tension leveler is 10-12 MPa, and the elongation is 0.2-1.0%.

[0018] Further, in step S4, the shearing involves the straightening machine removing 150-180 mm of waste material from the head and tail, and the suture removing 10-15 mm, with a cut edge width of 100 mm.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. By limiting the rolling angle and formulating reasonable cleaning, stitching, heat treatment and tension leveling processes, this invention can minimize the width of the ingot, avoid ingot casting cracks that lead to scrap, increase the weight of a single coil, reduce equipment operation, reduce waste generation, and thus improve production efficiency, which is very beneficial for large-scale production.

[0021] 2. The cleaning and sewing steps of the present invention can increase the weight of a single roll and double the production efficiency of the annealing furnace. At the same time, the cleaning machine, annealing furnace, and straightening machine can reduce a lot of aluminum coil hoisting and material roll loading and unloading operations, thereby reducing the amount of equipment operation.

[0022] 3. The present invention significantly reduces the amount of waste material removed during the production of finished products by tension straightening, resulting in a high yield. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0024] Figure 1 The aluminum alloy cold-rolled coil prepared in Example 1 has slight creases at the seam and roll joint;

[0025] Figure 2 The ingots that were scrapped due to cracks during the production process are shown in Comparative Example 2. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0027] Example 1

[0028] This embodiment prepares 5A06 alloy cold-rolled coils with a finished width of 2600 mm, a finished thickness of 1.2 mm, and a mill roll width of 2850 mm. The specific production method includes the following steps:

[0029] S1. Rolling: First, the ingot is obliquely rolled to increase its width to 2700mm, then longitudinally rolled to a thickness of 1.2mm to obtain an aluminum coil; during oblique rolling, the ingot head is positioned at a 15-degree angle to the rolls; the ingot specifications used are as follows:

[0030] Ingot width = finished product width 2600mm - 800mm = 1800mm, ingot length = mill roll width + 350mm = 3200mm, ingot thickness = 600mm, weight = 9.26 tons.

[0031] S2. Cleaning and sewing: Place the two aluminum coils on the sewing device of the cleaning machine and sew them together. The pressure of the sewing device is 12 MPa. The initial tensile stress of the cleaning machine is 16 MPa. After sewing, the tensile stress of the cleaning machine is set to 75% of the initial tensile stress.

[0032] S3. Heat treatment: The cleaned and sewn roll material is placed in a box furnace for heat treatment at a temperature of 120℃.

[0033] S4. Straightening: The heat-treated roll material is straightened and sheared by a straightening machine to obtain the finished product. The unwinding tension of the straightening machine is 11 MPa, the elongation is 0.5%, the straightening machine removes 160m of waste material at the beginning and end, removes 12m of seam material, and the cut edge width is 100mm.

[0034] The aluminum alloy cold-rolled coil ingot produced in this embodiment has a feed width of 1800mm, which is 30% narrower than the width of a normally produced ingot. This effectively avoids the generation of casting cracks in the ingot, and the creases at the seams are minimal. See details below. Figure 1 The red box shows that the roll material produced by the method in this embodiment has light creases, and the creases are basically invisible.

[0035] Example 2

[0036] This embodiment prepares 5A06 alloy cold-rolled coils with a finished width of 2600 mm, a finished thickness of 1.2 mm, and a mill roll width of 2850 mm. The specific production method includes the following steps:

[0037] S1. Rolling: First, the ingot is obliquely rolled to increase its width to 2700mm, then longitudinally rolled to a thickness of 1.2mm to obtain an aluminum coil; during oblique rolling, the ingot head is positioned at a 30-degree angle to the rolls; the ingot specifications used are as follows:

[0038] Ingot width = finished product width 2600mm - 800mm = 1800mm, ingot length = mill roll width + 350mm = 3200mm, ingot thickness = 600mm, weight = 9.26 tons.

[0039] S2. Cleaning and sewing: Place the three aluminum coils on the sewing device of the cleaning machine and sew them together. The pressure of the sewing device is 12 MPa. The initial tensile stress of the cleaning machine is 16 MPa. After sewing, the tensile stress of the cleaning machine is set to 75% of the initial tensile stress.

[0040] S3. Heat treatment: The cleaned and sewn roll material is placed in a box furnace for heat treatment at a temperature of 350℃.

[0041] S4. Straightening: The heat-treated roll material is straightened and sheared by a straightening machine to obtain the finished product. The unwinding tension of the straightening machine is 11 MPa, the elongation is 0.5%, the straightening machine removes 170m of waste material at the beginning and end, removes 12m of seam material, and the cut edge width is 100mm.

[0042] The aluminum alloy cold-rolled coils prepared in this embodiment have no crack defects, the ingot casting has no cracks, and the creases at the seams are slight.

[0043] Example 3

[0044] This embodiment prepares 5A06 alloy cold-rolled coils with a finished width of 2600 mm, a finished thickness of 1 mm, and a mill roll width of 2850 mm. The specific production method includes the following steps:

[0045] S1. Rolling: First, the ingot is obliquely rolled to increase its width to 2800mm, then longitudinally rolled to a thickness of 1mm to obtain an aluminum coil; during oblique rolling, the ingot head is positioned at a 60-degree angle to the rolls; the ingot specifications used are as follows:

[0046] Ingot width = finished product width 2600mm - 200mm = 2400mm, ingot length = mill roll width + 100mm = 2950mm, ingot thickness = 500mm, weight = 9.48 tons.

[0047] S2. Cleaning and sewing: Place the three aluminum coils on the sewing device of the cleaning machine and sew them together. The pressure of the sewing device is 13 MPa. The initial tensile stress of the cleaning machine is 14 MPa. After sewing, the tensile stress of the cleaning machine is set to 70% of the initial tensile stress.

[0048] S3. Heat treatment: The cleaned and sewn roll material is placed in a box furnace for heat treatment at a temperature of 300℃.

[0049] S4. Straightening: The heat-treated roll material is straightened and sheared by a straightening machine to obtain the finished product. The unwinding tension of the straightening machine is 10 MPa, the elongation is 0.2%, the straightening machine removes 150m of waste material at the beginning and end, removes 10m of seam material, and the cut edge width is 200mm.

[0050] The aluminum alloy cold-rolled coils prepared in this embodiment have no crack defects, the ingot casting has no cracks, and the creases at the seams are slight.

[0051] Example 4

[0052] This embodiment prepares 5A06 alloy cold-rolled coils with a finished width of 2600 mm, a finished thickness of 1.2 mm, and a mill roll width of 2850 mm. The production method includes the following steps:

[0053] S1. Rolling: First, the ingot is obliquely rolled to increase its width to 2750mm, then longitudinally rolled to a thickness of 1.2mm to obtain an aluminum coil; during oblique rolling, the ingot head is positioned at a 55-degree angle to the rolls; the ingot specifications used are as follows:

[0054] Ingot width = finished product width 2600mm - 1000mm = 1600mm, ingot length = mill roll width + 800mm = 3650mm, ingot thickness = 650mm, weight = 10.17 tons.

[0055] S2. Cleaning and sewing: Place the two aluminum coils on the sewing device of the cleaning machine and sew them together. The pressure of the sewing device is 12 MPa. The initial tensile stress of the cleaning machine is 18 MPa. After sewing, the tensile stress of the cleaning machine is set to 80% of the initial tensile stress.

[0056] S3. Heat treatment: The cleaned and sewn roll material is placed in a box furnace for heat treatment at a temperature of 200℃.

[0057] S4. Straightening: The heat-treated roll material is straightened and sheared by a straightening machine to obtain the finished product. The unwinding tension of the straightening machine is 12 MPa, the elongation is 1.0%, the straightening machine removes 180m of waste material at the beginning and end, removes 15m of seam material, and the cut edge width is 150mm.

[0058] The aluminum alloy cold-rolled coils prepared in this embodiment have no crack defects, the ingot casting has no cracks, and the creases at the seams are slight.

[0059] Comparative Example 1

[0060] This comparative example uses existing processes to prepare 5A06 alloy cold-rolled coils with a finished width of 2600mm, a finished thickness of 1.2mm, and a mill roll width of 2850mm.

[0061] The ingot specifications used are: ingot width = 2000mm, ingot length = 2700mm, ingot thickness = 600mm, and weight = 8.7 tons. The process involves increasing the width to 2700mm by transverse rolling of the ingot, and then longitudinally rolling it to 1.2mm.

[0062] The waste weight and yield of each embodiment and comparative example were calculated, and the results are shown in Table 1:

[0063] Table 1

[0064]

[0065] If Comparative Example 1 were to produce the same weight as Example 2 (3.2 times the weight), the total weight of waste would be: 0.322 × 3.2 + 1.254 × 3.2 = 5 tons, while the total weight of waste in Example 2 would only be 1.542 tons + 1.427 tons = 2.969 tons. It is evident that the method of this invention can improve yield and production efficiency while reducing waste generation.

[0066] Comparative Example 2

[0067] This comparative example prepared 5A06 alloy cold-rolled coils with a finished width of 2600mm, a finished thickness of 1.2mm, and a mill roll width of 2850mm. An ingot with a width of 2700mm, a length of 6000mm, a thickness of 600mm, and a weight of 9.26 tons was used. The ingot's feeding width of 2700mm makes it highly susceptible to cracking defects during the casting process, potentially leading to the scrapping of the entire ingot. This results in high casting difficulty and a low success rate. Figure 2 These are ingots that were scrapped due to cracks during the production process; the white line in the middle represents the crack.

[0068] In summary, this invention, by limiting the rolling angle and formulating reasonable cleaning, stitching, heat treatment, and straightening processes, can minimize the ingot width, avoid ingot cracks leading to scrap, increase the weight per coil, reduce equipment operation, and decrease waste generation, thereby improving production efficiency and making it highly suitable for large-scale production. The cleaning and stitching steps of this invention can increase the weight per coil, significantly improve the production efficiency of the annealing furnace, and reduce the need for manual handling of aluminum coils by the cleaning machine, annealing furnace, and straightening machine, thus reducing equipment operation. This invention also significantly reduces the amount of head and tail waste removed during the straightening process, resulting in a high yield.

[0069] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method of producing an aluminum alloy cold-rolled coil, characterized by, It comprises the following steps: S1, rolling: first, the ingot is obliquely rolled to increase the width, and then longitudinally rolled to obtain an aluminum coil with a thickness of 1-1.2 mm; When the ingot is obliquely rolled, the head of the ingot is placed at an angle of 15-60 degrees with the roller; The width of the ingot = the width of the finished product - (200-1000) mm, the length of the ingot = the width of the rolling mill roll surface + (100-800) mm, and the thickness of the ingot = 500-650 mm; S2, cleaning and stitching: 2-3 aluminum coils are placed at the stitching device of the cleaning machine for stitching and coiling, the pressure of the stitching device is 12-13 Mpa, the initial tensile stress of the cleaning machine is 14-18 Mpa, and the tensile stress of the cleaning machine after stitching is set to 70-80% of the initial tensile stress; S3, heat treatment: the coil after cleaning and stitching is subjected to heat treatment, and the heat treatment temperature is 120-350℃; S4, straightening and cutting: the coil after heat treatment is straightened and cut by a straightening and cutting machine, and the finished product is obtained; The unwinding tensile stress of the straightening and cutting machine is 10-12 Mpa, and the elongation is 0.2-1.0%.

2. The method of producing an aluminum alloy cold-rolled coil according to claim 1, characterized by, In step S3, the heat treatment is performed in a box-type furnace.

3. The method of claim 1, wherein the aluminum alloy cold-rolled coil is produced by a process comprising: In step S4, the cutting is to cut off 150-180 m of waste material at the head and tail of the straightening and cutting machine, cut off 10-15 m at the stitching position, and the cutting edge width is 100 mm.

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