A method for manufacturing an aluminum alloy foil for an automobile horn

Abstract

The application provides a preparation method of an aluminum alloy foil for a car horn, comprising the following steps: S1, ingredient and tool selection; S2, smelting; S3, continuous casting and rolling; S4, post-processing: cold rolling and annealing of the cast and rolled coil, the annealing adopts a multi-stage temperature setting; S5, edge cutting: the aluminum coil is cooled to room temperature before edge cutting, and then the edge cutting is performed; S6, product annealing: after two-stage annealing, the product is cooled to room temperature, and then is inspected and delivered. By adjusting alloy components, parameters of a cold rolling process, heat treatment parameters, edge cutting modes and the like, the internal stress level is reduced to the lowest, the surface annealing oil spots are reduced to the maximum extent, and the agglomerated particles in the structure are crushed and broken, so that the modified 8XXX aluminum alloy material has more excellent metallographic structure, better product strength, forming performance and surface quality, and the tensile strength and elongation meet the use requirements of the aluminum alloy foil for the horn.

Description

Technical Field

[0001] This invention relates to a method for preparing aluminum alloy foil for automobile horns. Background Technology

[0002] A car horn is an audio signal device used in automobiles. During driving, the driver emits necessary audio signals as needed and according to regulations to warn pedestrians and other vehicles, ensuring traffic safety. It can also be used to urge movement and transmit signals. Its working principle involves the vibration of a metal diaphragm to produce sound. Depending on the vibration source, horns can be divided into different types, including air horns that use compressed air to vibrate a metal diaphragm, and electric horns that use a change in electric current to generate magnetic force, causing an armature to move and thus forcing the metal diaphragm to vibrate.

[0003] Therefore, based on the specific manufacturing requirements and operating principles of automobile horns, higher requirements are placed on the performance of the metal diaphragm of automobile horns in all aspects, mainly reflected in processing performance, ductility and surface quality to ensure the needs of manufacturing and operation.

[0004] Currently, the raw material used for aluminum alloy foil in car horns is 8XXX alloy. 8XXX alloy has good aluminum foil ductility, but its strength is relatively high after annealing and there are inevitably some annealing spots on the surface. Therefore, further research and development optimization is needed. Summary of the Invention

[0005] To reduce oil stains on the surface of aluminum alloy foil for automobile horns, while simultaneously lowering the strength of the finished product and improving elongation and uniformity of the microstructure, this invention provides a method for preparing aluminum alloy foil for automobile horns, the specific scheme of which is as follows:

[0006] A method for preparing an aluminum alloy foil sheet for an automobile horn includes the following steps:

[0007] S1. Selection of raw materials and tools: Aluminum alloy raw materials are selected, including aluminum ingots and recycled aluminum alloy raw materials. The alloy composition ratio in the aluminum alloy raw materials is Pb≤0.01%, Hg≤0.01%, and Cr≤0.01%. Steel with an alloy ratio of Pb≤0.01%, Hg≤0.01%, and Cr≤0.01% is selected as the slag removal and refining tools.

[0008] S2. Smelting: Pour the aluminum alloy raw material into the smelting furnace for smelting. After refining, let it stand and remove the slag. Test the alloy composition in the smelting furnace and control it within a certain range. Additives are added if necessary. When the composition meets the requirements, pour the furnace and refine the aluminum liquid after standing in the furnace once.

[0009] S3. Continuous casting and rolling: Molten aluminum is continuously cast and rolled by two rollers to form cast coils;

[0010] S4. Post-processing: The cast-rolled coil is cold-rolled and annealed, and the annealing adopts a multi-stage temperature setting;

[0011] S5. Trimming: Before trimming, cool the aluminum coil to room temperature, then trim the edges. After trimming, roll the aluminum coil to the target thickness.

[0012] S6. Finished product annealing: After two-stage annealing, the product is cooled to room temperature before inspection and delivery.

[0013] Furthermore, the specific parameters for the multi-stage temperature setting used in S4 annealing are as follows:

[0014] The furnace gas temperature is set to rise to 230℃~280℃ over 2.5~3.5 hours and held for 3~6 hours. After holding, the furnace gas temperature is set to rise to 480℃~580℃ over 3 hours. After the metal temperature reaches 380℃~480℃, it is held for 3~6 hours. After holding, the temperature is set to drop to 200~280℃ over 3 hours and held for 3 hours before being removed from the furnace. The aluminum coil is then subjected to forced cooling. After cooling to room temperature, it is rolled to the required thickness for the trimmed edge.

[0015] Furthermore, the specific parameters for the two-end annealing in S6 are as follows: the furnace gas temperature is set to be raised to 210℃~260℃ after 6 hours, and after the metal temperature reaches 200~250℃, it is held for 3~6 hours. Finally, the furnace gas is cooled to 150℃ after 3 hours before being taken out of the furnace.

[0016] Furthermore, the alloy element composition controlled in S2 smelting is as follows: Si 0.3%–0.6%; Fe 0.4%–0.8%; Mn ≤0.01%–0.03%; Cu 0.03%–0.10%; Ti 0.02%–0.06%.

[0017] To address the issues of uneven microstructure and particle agglomeration that are prone to occur in continuous casting and rolling processes, the S4 cold rolling step involves rolling and thinning the material by more than 5 times before undergoing an intermediate first heat treatment. After rolling to a thickness of 0.2–0.4 mm, the material is cooled to room temperature and then trimmed. After trimming, rolling continues to the finished thickness, maintaining an overall reduction in rolling thickness of ≥50 times.

[0018] Furthermore, the settling time in S2 is 20–40 minutes.

[0019] Furthermore, the thickness of the cast-rolled coil in S3 is 7.5–8.5 mm.

[0020] Furthermore, the target thickness in S5 is 0.1–0.15 mm.

[0021] Beneficial effects:

[0022] This invention provides a method for preparing aluminum alloy foil for automobile horns, which has the following advantages compared with the prior art:

[0023] (1) Based on the existing 8XXX alloy, control the content of silicon, iron, copper, manganese and titanium. Controlling the content of silicon, iron and manganese can reduce component segregation and lower the recrystallization temperature of the metal. Controlling the content of copper and titanium can improve the ductility of the material. At the same time, since the alloy composition is lower than that of conventional 8XXX, the application of additives can be reduced.

[0024] (2) Before the first annealing, the coil is rolled thinned by more than 5 times, and the finished product is rolled thinned by more than 50 times. This can ensure that the internal structure of the cast and rolled coil is broken to a certain extent and reduce the agglomerate particles. Through cold extrusion deformation, more deformation areas are generated in the metallographic structure. The above methods can prevent the generation of large grains and effectively improve the internal grains, thereby reducing the tensile strength of the final product and increasing the elongation to meet the use of aluminum foil.

[0025] (3) In order to release internal stress, reduce the strength of finished product and increase elongation, and at the same time reduce surface annealing oil spots, this preparation method performs two heat treatments. The first treatment is a high-temperature segmented treatment, which can reduce surface high-temperature annealing oil spots so as not to be inherited to finished product, and reduce the material recrystallization temperature, which can reduce the annealing temperature of finished product. The finished product is then subjected to low-temperature segmented heat treatment to further reduce annealing oil spots.

[0026] (4) In order to further release internal stress and improve surface flatness to obtain more uniform products, the aluminum coil is cooled to room temperature before the first annealing, rolling and trimming. This can ensure uniform temperature variation of the aluminum coil and reduce unevenness of the plate shape caused by uneven material temperature and deformation of the plate surface during hot processing.

[0027] The aluminum alloy foil was tested and found to have a tensile strength ≥100MPa, an elongation of 22% to 25%, a cupping value of 6.5mm to 7.0mm, and no annealing spots on the surface. Detailed Implementation

[0028] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0029] Example 1:

[0030] A method for preparing an aluminum alloy foil sheet for automobile horns includes the following steps:

[0031] S1. Selection of raw materials and tools: Select aluminum alloy raw materials that have passed acceptance inspection, including aluminum ingots and recycled aluminum alloy raw materials, with lead content of 0.002%, mercury content of ≤0.002%, and chromium content of ≤0.003%; select steel with lead content of 0.001%, mercury content of ≤0.001%, and chromium content of ≤0.004% to make slag removal and refining tools.

[0032] S2. Smelting: After adding aluminum alloy raw materials, ignite and melt. After refining, let it stand for 25 minutes, then remove slag, test the composition and add additives. When the composition meets the requirements, pour the furnace and refine the aluminum liquid after standing in the furnace once. After the composition is adjusted, the content is 0.56% silicon, 0.72% iron, 0.012% manganese, 0.04% copper, and 0.04% titanium.

[0033] S3. Continuous casting and rolling: Molten aluminum is continuously cast and rolled using two rollers to produce cast coils with a thickness of 7.8 mm.

[0034] S4. Post-processing: The cast-rolled aluminum coils are cold-rolled and annealed. The cold rolling is carried out to 1.2mm, followed by the first intermediate heat treatment. After rolling to a thickness of 0.28mm, the coils are cooled to room temperature and trimmed. After trimming, the coils are rolled to a finished thickness of 0.13mm, resulting in an overall reduction in thickness by 60 times. The coils are then annealed. The first annealing process involves multi-stage temperature settings. First, the furnace gas temperature is set to rise to 260℃ after 3 hours and held for 3 hours. Then, the furnace gas temperature is set to rise to 550℃ after 3 hours. Once the metal temperature reaches 380℃, the temperature is held for 6 hours. Finally, the furnace gas temperature is lowered to 200℃ after 3 hours and held for 3 hours before the coils are removed from the furnace. The aluminum coils are then subjected to forced cooling. After cooling to room temperature, the coils are rolled to the trimmed thickness.

[0035] S5. Trimming: Before trimming, the aluminum coil is cooled to room temperature and then trimmed. After trimming, the aluminum coil is rolled to a target thickness of 0.13mm.

[0036] S6. Finished product annealing: First, the furnace gas temperature is raised to 210℃ after 6 hours. After the metal temperature reaches 200℃, it is held at that temperature for 3 hours. Finally, the furnace gas is cooled to 150℃ after 3 hours and then removed from the furnace. After cooling to room temperature, it is inspected and delivered.

[0037] The aluminum alloy foil prepared in Example 1 was subjected to performance testing, and the finished product had a tensile strength of 105 MPa, an elongation of 22%, a cupping of 6.5 mm, and no visible annealing spots on the surface.

[0038] Example 2:

[0039] A method for preparing an aluminum alloy foil sheet for automobile horns includes the following steps:

[0040] S1. Selection of raw materials and tools: Select aluminum alloy raw materials that have passed acceptance inspection, including aluminum ingots and recycled aluminum alloy raw materials, with lead content of 0.001%, mercury content of ≤0.002%, and chromium content of ≤0.004%; select steel with lead content of 0.001%, mercury content of ≤0.001%, and chromium content of ≤0.002% to make slag removal and refining tools.

[0041] S2. Smelting: After adding aluminum alloy raw materials, ignite and melt. After refining, let it stand for 30 minutes, then remove slag, test the composition and add additives. When the composition meets the requirements, pour the furnace and refine the aluminum liquid after standing in the furnace once. After the composition is adjusted, the content is 0.58% silicon, 0.77% iron, 0.015% manganese, 0.05% copper, and 0.05% titanium.

[0042] S3. Continuous casting and rolling: Molten aluminum is continuously cast and rolled using two rollers to produce cast coils with a thickness of 7.5mm.

[0043] S4. Post-processing: The cast-rolled aluminum coils are cold-rolled and annealed. The cold rolling is carried out to 1.3mm, followed by the first intermediate heat treatment. After rolling to 0.35mm thickness, the coils are cooled to room temperature and trimmed. After trimming, the coils are rolled to the finished thickness of 0.13mm, resulting in an overall reduction in thickness of 57 times. The coils are then annealed. The first annealing process involves multi-stage temperature settings. First, the furnace gas temperature is set to rise to 265℃ after 3 hours and held for 4 hours. Then, the furnace gas temperature is set to rise to 560℃ after 3 hours. Once the metal temperature reaches 460℃, the temperature is held for 3 hours. Finally, the furnace gas temperature is lowered to 220℃ after 3 hours and held for 3 hours before the coils are removed from the furnace. The aluminum coils are then subjected to forced cooling. After cooling to room temperature, the coils are rolled to the trimmed thickness.

[0044] S5. Trimming: Before trimming, the aluminum coil is cooled to room temperature and then trimmed. After trimming, the aluminum coil is rolled to a target thickness of 0.13mm.

[0045] S6. Finished product annealing: First, the furnace gas temperature is raised to 260℃ after 6 hours. After the metal temperature reaches 250℃, it is held at that temperature for 3 to 6 hours. Finally, the furnace gas is cooled to 150℃ after 3 hours and then removed from the furnace. After cooling to room temperature, it is inspected and delivered.

[0046] The aluminum alloy foil prepared in Example 2 was subjected to performance testing, and the finished product had a tensile strength of 100 MPa, an elongation of 25%, a cupping of 7.0 mm, and no visible annealing spots on the surface.

[0047] Example 3:

[0048] A method for preparing an aluminum alloy foil sheet for automobile horns includes the following steps:

[0049] S1. Raw Material and Tool Selection: Select aluminum alloy raw materials that have passed acceptance testing, including aluminum ingots and recycled aluminum alloy raw materials, with lead content ≤0.002%, mercury content ≤0.001%, and chromium content ≤0.003%; select steel with lead content ≤0.001%, mercury content ≤0.001%, and chromium content ≤0.002% to make slag removal and refining tools.

[0050] S2. Smelting: After adding aluminum alloy raw materials, ignite and melt. After refining, let it stand for 35 minutes, then remove slag, test the composition and add additives. When the composition meets the requirements, pour the furnace and refine the aluminum liquid after standing in the furnace once. After the composition is adjusted, the content is 0.55% silicon, 0.74% iron, 0.02% manganese, 0.03% copper, and 0.03% titanium.

[0051] S3. Continuous casting and rolling: Molten aluminum is continuously cast and rolled by two rollers to produce cast and rolled coils with a thickness of 8mm.

[0052] S4. Post-processing: The cast-rolled aluminum coils are cold-rolled and annealed. The cold rolling is carried out to 1.5mm, followed by the first intermediate heat treatment. After rolling to a thickness of 0.35mm, the coils are cooled to room temperature and the edges are trimmed. After trimming, the coils are rolled to a finished thickness of 0.13mm, resulting in an overall reduction in thickness of 61 times. The coils are then annealed. The first annealing process involves multi-stage temperature settings. First, the furnace gas temperature is set to rise to 260℃ after 3 hours and held for 4 hours. Then, the furnace gas temperature is set to rise to 550℃ after 3 hours. Once the metal temperature reaches 420℃, the temperature is held for 3 hours. Finally, the furnace gas temperature is lowered to 200℃ after 3 hours and held for 3 hours before the coils are removed from the furnace. The aluminum coils are then subjected to forced cooling. After cooling to room temperature, the coils are rolled to the trimmed thickness.

[0053] S5. Trimming: Before trimming, the aluminum coil is cooled to room temperature and then trimmed. After trimming, the aluminum coil is rolled to a target thickness of 0.13mm.

[0054] S6. Finished product annealing: First, the furnace gas temperature is raised to 230℃ after 6 hours. After the metal temperature reaches 230℃, it is held at that temperature for 5 hours. Finally, the furnace gas is cooled to 150℃ after 3 hours and then removed from the furnace. After cooling to room temperature, it is inspected and delivered.

[0055] The aluminum alloy foil prepared in Example 3 was subjected to performance testing, and the finished product had a tensile strength of 106 MPa, an elongation of 25%, a cupping of 6.9 mm, and no visible annealing spots on the surface.

[0056] In summary, compared with existing aluminum alloy preparation methods, Examples 1-3, by adjusting alloy composition, cold rolling process parameters, heat treatment parameters, and edge trimming methods, minimized internal stress levels and reduced surface annealing oil spots to the greatest extent. Furthermore, the agglomerated particles in the microstructure were crushed and broken down, resulting in modified 8XXX aluminum alloy materials with superior metallographic structure, improved finished product strength, formability, and surface quality. Simultaneously, the tensile strength and elongation tested met the requirements for use in speaker aluminum alloy foil.

[0057] As a further improvement, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of producing an aluminum alloy foil for an automobile horn, characterized by, Includes the following steps: S1. Selection of raw materials and tools: Aluminum alloy raw materials are selected, including aluminum ingots and recycled aluminum alloy raw materials. The alloy composition ratio in the aluminum alloy raw materials is Pb 0.001%~0.002%, Hg≤0.002%, and Cr≤0.004%. Steel with an alloy ratio of Pb 0.001%, Hg≤0.001%, and Cr≤0.004% is selected as the slag removal and refining tools. S2. Smelting: The aluminum alloy raw material is poured into the smelting furnace for smelting. After refining, it is allowed to stand and slag is removed. The alloy composition in the smelting furnace is tested and the alloy element composition is controlled as follows: Si 0.55%~0.58%; Fe 0.72%~0.77%; Mn 0.012%~0.02%; Cu 0.03%~0.05%; Ti 0.03%~0.05%. Additives are added if necessary. When the composition meets the requirements, the furnace is turned over and the aluminum liquid after standing in the furnace is refined once. S3. Continuous casting and rolling: Molten aluminum is continuously cast and rolled by two rollers to form aluminum coils; S4. Post-processing: The aluminum coil is cold rolled and annealed. The annealing adopts a multi-stage temperature setting. The furnace gas temperature is set to be raised to 260℃~265℃ after 3 hours and held for 3~6 hours. After the holding period, the furnace gas temperature is set to be raised to 550℃~560℃ again after 3 hours. After the metal temperature reaches 380℃~460℃, it is held for 3~6 hours. After the holding period, the temperature is set to be lowered to 200~220℃ again after 3 hours and held for 3 hours before being removed from the furnace. The aluminum coil is then subjected to forced cooling. After cooling to room temperature, it is rolled to the required thickness for the trimmed edge. S5. Trimming: Before trimming, cool the aluminum coil to room temperature and then trim the edges. After trimming, roll the aluminum coil to the target thickness of 0.13mm. S6. Finished product annealing: After two-stage annealing, the product is cooled to room temperature before inspection and delivery.

2. The method for preparing an aluminum alloy foil sheet for an automobile horn according to claim 1, characterized in that, In step S6: the furnace gas temperature is set to be raised to 210℃~260℃ over 6 hours. After the metal temperature reaches 200~250℃, it is held for 3~6 hours. Finally, the furnace gas is cooled to 150℃ over 3 hours before being taken out of the furnace.

3. The method for preparing an aluminum alloy foil for an automobile horn according to claim 1, characterized in that, In step S4, after cold rolling to 1.2~1.5mm, an intermediate first heat treatment is performed. After rolling to a thickness of 0.28~0.35mm, the material is cooled to room temperature and the edges are trimmed. After trimming, rolling continues to the target thickness, maintaining an overall reduction in rolling thickness of 57~61 times.

4. The method for preparing an aluminum alloy foil for an automobile horn according to claim 1, characterized in that, The settling time in step S2 is 25-35 minutes.

5. The method for preparing an aluminum alloy foil for an automobile horn according to claim 1, characterized in that, In step S3, the thickness of the aluminum coil is 7.5~8mm.