5-series aluminum alloy strip for vehicle backlight panel and method for manufacturing the same

Abstract

The present application relates to a kind of 5 series aluminum alloy strip for vehicle-mounted backlight panel and its preparation method, belong to aluminum alloy processing manufacturing technical field.Aluminum alloy is according to the composition of mass percentage:Si:≤0.12%, Fe:0.2~0.3%, Cu:0.07~0.09%, Mn:0.35~0.45%, Mg:5.05~5.15%, Cr:0.02~0.04%, Zn≤0.03%, Ti:0.01~0.025%, single impurity≤0.03%, total impurities≤0.15%, the balance is Al.The preparation method of the present application includes: batching→smelting→refining→casting→saw cutting→milling→soaking→hot rolling→cold rolling→pulling straightening cleaning straightening→intermediate annealing→cold rolling→pulling straightening cleaning straightening→stabilization annealing→pulling straightening→inverted finished product→packaging.The present application realizes that product performance meets strength and plasticity requirement by adjusting component, optimizing hot rolling, annealing, stabilization, stretching straightening etc., reduces production cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aluminum alloy processing and manufacturing, and particularly relates to a 5-series aluminum alloy strip for a vehicle-mounted backlight plate and a preparation method thereof. BACKGROUND

[0002] High-strength steel materials are mainly used for the liquid crystal backlight plate of electronic products such as vehicle-mounted tablets and mobile phones. However, with the development of electronic products in the direction of thinness, lightness, easy heat conduction and functional integration, the shortcomings of steel materials gradually appear, and the advantages of aluminum alloys are continuously embodied.

[0003] The use requirements of the liquid crystal backlight plate of electronic products such as vehicle-mounted tablets and mobile phones need to ensure high-strength performance and prevent cracking during bending forming, so as to meet a certain plasticity. However, with the increase of the strength of the aluminum alloy, the plasticity decreases, and with the increase of the plasticity of the aluminum alloy, the strength decreases. SUMMARY

[0004] Therefore, the application discloses a 5-series aluminum alloy strip for a vehicle-mounted backlight plate and a preparation method thereof, which can meet the high-strength and high-plasticity performance, and the specific scheme is as follows.

[0005] The 5-series aluminum alloy for the vehicle-mounted backlight plate comprises the following components in percentage by mass: Si:≤0.12%, Fe:0.2-0.3%, Cu:0.07-0.09%, Mn:0.35-0.45%, Mg:5.05-5.15%, Cr:0.02-0.04%, Zn≤0.03%, Ti:0.01-0.025%, single impurity≤0.03%, total impurities≤0.15%, and the balance is Al.

[0006] The application further discloses a preparation method of the 5-series aluminum alloy strip for the vehicle-mounted backlight plate, which comprises the following steps.

[0007] A. After the aluminum alloy is proportioned in percentage by mass, melting and in-furnace refining are performed, and the aluminum liquid is cast into an aluminum alloy ingot;

[0008] B. After the aluminum alloy ingot is cooled, the head and tail are cut off, and the surface of the ingot is milled to remove the condensate layer;

[0009] C. The ingot after sawing and milling is placed in a push-type heating furnace for soaking, the metal temperature is 480-530 DEG C, and the temperature is maintained for 2-5 hours;

[0010] D. The ingot is hot-rolled out of the furnace, the final rolling temperature of the hot rolling is controlled to be 310-335 DEG C, and the thickness of the hot-rolled coil is 2.2-2.8 mm;

[0011] E. The coil is forcedly cooled, and cold rolling is performed after the coil is cooled to room temperature;

[0012] F, after cold rolling, cleaning, first stretching straightening, then coiling into the box annealing furnace for annealing, during annealing process, protective atmosphere treatment, oxygen content is less than or equal to 0.3%, annealing system is that when the coil core reaches 305 DEG C, keeping warm for 4 hours, reaching the complete O organization, after intermediate annealing, cooling to room temperature;

[0013] G, the coil is cold-rolled to the finished thickness;

[0014] H, after cold rolling, cleaning, second stretching straightening, coiling into the box annealing furnace for stabilization treatment, after stabilization, cooling to room temperature;

[0015] I, the 5 series aluminum alloy strip prepared in step H is cut and packaged.

[0016] As a supplement to the technical scheme of the application, in step E, the cold rolling thickness is reserved 50% to 60% of the cold rolling processing rate from the intermediate annealing thickness to the finished thickness.

[0017] As a supplement to the technical scheme of the application, the intermediate annealing thickness is 0.40mm to 0.75mm.

[0018] As a supplement to the technical scheme of the application, in step H, the stabilization treatment system is that when the coil core reaches 150 DEG C to 200 DEG C, keeping warm for 4 hours.

[0019] As a supplement to the technical scheme of the application, in step H, the third stretching straightening is performed on the strip after stabilization treatment.

[0020] As a supplement to the technical scheme of the application, in step H, the second stretching straightening stretching rate is 0.4% to 0.6%.

[0021] As a supplement to the technical scheme of the application, in step H, the third stretching straightening stretching rate is 0.3% to 0.5%.

[0022] As a supplement to the technical scheme of the application, in step F, the first stretching straightening stretching rate is 0.3% to 0.5%.

[0023] Beneficial effects: the 5 series aluminum alloy strip for vehicle-mounted backlight plate and the preparation method thereof disclosed by the application optimize the alloy composition, and optimize the hot rolling, annealing, stabilization, stretching straightening and other steps in the preparation method, the prepared aluminum alloy strip has a tensile strength of more than 350Mpa, a yield strength of more than 280Mpa, and an elongation after fracture of more than 9.5%, and does not break after bending 180 DEG. DETAILED DESCRIPTION

[0024] A kind of 5 series aluminum alloy strip for vehicle-mounted backlight panel and its preparation method, for providing a kind of aluminum product to replace steel material, which can guarantee high strength and can guarantee that bending (180 degrees 0t bending, i.e. 180 degrees bending, r angle is 0) does not crack.

[0025] Specific production steps are as follows:

[0026] A, according to the following aluminum alloy mass percentage ingredients, smelting, in-furnace refining, on-line degassing, on-line filtration are carried out, and then aluminum alloy ingot is cast.

[0027] Si:≤0.12%, Fe:0.2~0.3%, Cu:0.07~0.09%, Mn:0.35~0.45%, Mg:5.05~5.15%; Cr:0.02~0.04%; Zn≤0.03%; Ti:0.01~0.025%, single impurity≤0.03%, total impurities≤0.15%, the balance is Al.

[0028] The smelting process is specifically as follows: the ingredients are sequentially put into the smelting furnace for smelting, and flux is used for refining covering, after the materials in the furnace are melted, stirring is started, and then refining and slagging are carried out, after the qualified chemical composition is obtained, Ar gas and Cl2 mixed gas are used to bring hydrogen and fine impurities in the aluminum liquid to the surface of the melt, so as to reduce the gas content of the melt.

[0029] Further, two-stage filtration is used in the casting process of step A, including but not limited to: plate type CFF filtration+plate type CFF filtration, plate type CFF filtration+deep bed filtration, plate type CFF filtration+tube type filtration, so as to reduce the slag content of the melt, ensure the purity of the melt, and avoid the black silk and black line caused by impure melt, and ensure the surface quality. Al-5Ti-B is used for on-line refining treatment to ensure the grain size of the aluminum alloy ingot.

[0030] B, after the aluminum alloy ingot is cooled, the head and tail are cut off, and the surface of the ingot is removed by milling;

[0031] C, the ingot after sawing and milling is placed in a push-type heating furnace for soaking, and the metal temperature is 480℃~530℃, and the temperature is kept for 2~5 hours;

[0032] D, the ingot is hot rolled out of the furnace, the final rolling temperature of hot rolling is controlled to be 310℃~335℃, and the thickness of the hot rolled coil is 2.2mm~2.8mm;

[0033] E, the coil is forcedly cooled, and after being cooled to room temperature, cold rolling is carried out to medium reduction thickness, and the medium reduction thickness is 50%~60% of the cold rolling processing rate of the finished product thickness;

[0034] F, after cold rolling, cleaning, first stretch straightening, the stretch rate of the stretch straightening is 0.3%-0.5%, then coiling enters the box annealing furnace to anneal, carries out protective atmosphere treatment during annealing, the oxygen content is less than or equal to 0.3%, the annealing system is that the core of the coiled material reaches 305 DEG C, and the temperature is kept for 4 hours to reach the complete O organization, after the intermediate annealing, the temperature is cooled to room temperature;

[0035] G, the coiled material is cold rolled to the finished thickness;

[0036] H, after cold rolling, cleaning, second stretch straightening, the stretch rate of the stretch straightening is 0.4%-0.6%, then coiling enters the box annealing furnace to carry out stabilization treatment, the stabilization treatment system is that the core of the coiled material reaches 150 DEG C-200 DEG C, and the temperature is kept for 4 hours, then the temperature is cooled to room temperature, and the third stretch straightening is carried out, the stretch rate of the stretch straightening is 0.3%-0.5%;

[0037] I, the 5 series aluminum alloy strip prepared in step H is cut and packaged.

[0038] As a supplement to the above technical scheme, the alloy state of the 5 series aluminum alloy strip is 5 series-H38, and the thickness is 0.2 mm-0.3 mm.

[0039] In the above technical scheme, when the alloy composition is selected, the alloy composition is optimized, Mg is taken as the main alloying element, the content of Mg is increased in the melt, and the content of Mn and Cu is limited in a very small range, so that the prepared aluminum alloy strip has high strength and extremely stable mechanical properties. While the strength is improved, the plasticity is reduced, which is improved by reducing the intermediate annealing rate to 50%-60% in the subsequent process, adjusting the stabilization annealing temperature to 150 DEG C-200 DEG C, and prolonging the annealing time to 4 hours.

[0040] On the basis of the above alloy composition optimization, the thickness of the hot-rolled coil is reduced, the thickness of the hot-rolled coil is 5.5 mm using the traditional process, and the thickness of the hot-rolled coil is reduced to 2.5 mm in the present application, which reduces 2 times of cold rolling and 1 time of intermediate annealing, reduces the production process, saves energy consumption while meeting the performance index.

[0041] By optimizing the reserved processing rate of intermediate annealing and increasing the stabilization annealing system, it is beneficial to obtain a high-strength aluminum alloy material with a tensile strength of more than 350 MPa and a 180° 0t bending without cracking, and the reserved processing rate is too high, and the stabilization time is too short, which will lead to insufficient plasticity.

[0042] At the same time, by adopting three times of stretching straightening, the coil and longitudinal strip shape are qualified, the small plate and punched plate surface are not deformed, and the plate shape characteristics meet the use requirements; among them, the second stretching and bending straightening (stretching rate of 0.4-0.6%) preliminarily removes internal stress and reduces transverse bending; the third stretching and bending straightening (stretching rate of 0.3-0.5%) further removes internal stress and straightens the transverse bending. The internal stress is mainly caused by the uneven longitudinal calendering deformation of the strip during the rolling process, including the finished product pass rolling process. If the internal stress is not treated by straightening in the subsequent process, the longitudinal striping and small plate cutting of the subsequent customer will be warped and unqualified.

[0043] Example 1:

[0044] A, according to the following aluminum alloy mass percentage ingredients, melt, in-furnace refining, on-line degassing, on-line filtering, and then cast into aluminum alloy ingot.

[0045] Si: 0.071%, Fe: 0.225%, Cu: 0.081%, Mn: 0.385%, Mg: 5.105%, Cr: 0.027%, Zn: 0.018%, Ti: 0.019%, single impurity ≤0.03%, total impurities ≤0.15%, and the balance is Al.

[0046] The melting process is as follows: the ingredients are sequentially put into the melting furnace for melting, and flux is used for refining coverage. After the materials in the furnace are melted, stirring is started, and then refining and slagging are carried out. After obtaining qualified chemical composition, Ar gas and Cl2 mixed gas are used to bring hydrogen and fine impurities in the aluminum liquid to the surface of the melt, thereby reducing the gas content of the melt.

[0047] Further, a two-stage filtration is used in the casting process of step A, including but not limited to: plate type CFF filtration + plate type CFF filtration, plate type CFF filtration + deep bed filtration, and plate type CFF filtration + tube type filtration, thereby reducing the slag content of the melt, ensuring the purity of the melt, and avoiding the black silk and black line caused by impure melt, and ensuring the surface quality. Al-5Ti-B is used for online refining treatment to ensure the grain size of the aluminum alloy ingot.

[0048] B, after the aluminum alloy ingot is cooled, the head and tail are cut off, and the surface of the ingot is milled to remove the condensate layer;

[0049] C, the sawed and milled ingot is placed in a push-type heating furnace for soaking, and the metal temperature is 490°C, and the soaking time is 3.5 hours;

[0050] D, the ingot is hot rolled out of the furnace, and the final rolling temperature of hot rolling is controlled to 325°C, and the hot rolling coil thickness is 2.5mm;

[0051] E. The coiled material is forcedly cooled, and after cooling to room temperature, cold rolling is performed to a medium thickness of 0.53 mm;

[0052] F. After cold rolling, cleaning and first stretching straightening are performed, the stretching rate of the first stretching straightening is 0.4%, and then after coiling, annealing is performed in a box-type annealing furnace, a protective atmosphere treatment is performed during annealing, the oxygen content is less than or equal to 0.3%, and the annealing system is that when the core of the coiled material reaches 305 DEG C, the temperature is maintained for 4 hours to reach a completely O-shaped structure, and after intermediate annealing, the coiled material is cooled to room temperature;

[0053] G. The coiled material is cold rolled to a finished thickness of 0.25 mm;

[0054] H. After cold rolling, cleaning and second stretching straightening are performed, the stretching rate of the second stretching straightening is 0.5%, and then after coiling, stabilization treatment is performed in a box-type annealing furnace, the stabilization treatment system is that when the core of the coiled material reaches 180 DEG C, the temperature is maintained for 4 hours, and then the coiled material is cooled to room temperature, and third stretching straightening is performed, the stretching rate of the third stretching straightening is 0.4%.

[0055] I. The 5-series aluminum alloy strip prepared in step H is cut and packaged.

[0056] Example 2:

[0057] A. According to the following aluminum alloy mass percentage, ingredients are prepared for melting, in-furnace refining, online degassing, online filtering, and then cast into aluminum alloy ingots.

[0058] Si: 0.068%, Fe: 0.235%, Cu: 0.087%, Mn: 0.381%, Mg: 5.102%, Cr: 0.025%, Zn: 0.015%, Ti: 0.017%, single impurity less than or equal to 0.03%, total impurities less than or equal to 0.15%, and the balance is Al.

[0059] The melting process is as follows: the ingredients are sequentially put into the melting furnace for melting, and a flux is used for refining coverage. After the materials in the furnace are melted, stirring is started, and then refining and slagging are performed. After obtaining qualified chemical components, Ar gas and Cl2 mixed gas are used to bring hydrogen and fine impurities in the aluminum liquid to the surface of the melt, thereby reducing the gas content of the melt.

[0060] Further, a double-stage filter is used during the casting process of step A, including but not limited to: plate-type CFF filter + plate-type CFF filter, plate-type CFF filter + deep bed filter, and plate-type CFF filter + tubular filter, thereby reducing the slag content of the melt, ensuring the purity of the melt, and avoiding black silk and black lines caused by impure melt, thereby ensuring the surface quality. Al-5Ti-B is used for online refining treatment to ensure the grain size of the aluminum alloy ingot.

[0061] B, the aluminum alloy ingot is cut and the tail is removed after cooling, and the condensate layer on the surface of the ingot is removed by milling;

[0062] C, the ingot after sawing and milling is placed in a push-type heating furnace for soaking, and the metal temperature is 500 DEG C, and the temperature is kept for 3 hours;

[0063] D, the ingot is hot-rolled out of the furnace, and the final rolling temperature of hot rolling is controlled to 320 DEG C, and the thickness of the hot-rolled coil is 2.4 mm;

[0064] E, the coil is forcedly cooled, and after cooling to room temperature, cold rolling is carried out to a medium thickness of 0.56 mm;

[0065] F, after cold rolling, cleaning and stretch straightening are carried out, the first stretch straightening has a stretch rate of 4.5%, then the coil is wound and enters the box-type annealing furnace for annealing, the oxygen content in the protective atmosphere during annealing is ≤0.3%, the annealing system is that when the core of the coil reaches 305 DEG C, the temperature is kept for 4 hours to reach the complete O state, and after the intermediate annealing, the coil is cooled to room temperature;

[0066] G, the coil is cold-rolled to a finished thickness of 0.25 mm;

[0067] H, after cold rolling, cleaning and the second stretch straightening are carried out, the second stretch straightening has a stretch rate of 0.45%, then the coil is wound and enters the box-type annealing furnace for stabilization treatment, the stabilization treatment system is that when the core of the coil reaches 175 DEG C, the temperature is kept for 4 hours, and then the coil is cooled to room temperature; and the third stretch straightening is carried out, and the third stretch straightening has a stretch rate of 0.35%.

[0068] I, the 5 series aluminum alloy strip prepared in step H is cut and packaged.

[0069] Example 3:

[0070] A, according to the following aluminum alloy mass percentage, the ingredients are melted, refined in the furnace, degassed on line, filtered on line, and then cast into aluminum alloy ingots.

[0071] Si: 0.074%, Fe: 0.215%, Cu: 0.088%, Mn: 0.391%, Mg: 5.095%, Cr: 0.032%, Zn: 0.016%, Ti: 0.020%, single impurity ≤0.03%, total impurities ≤0.15%, and the balance is Al.

[0072] The melting process is as follows: the ingredients are sequentially put into the melting furnace for melting, and flux is used for refining covering, after the materials in the furnace are melted, stirring is started, and then refining and slagging are carried out, after the qualified chemical composition is obtained, Ar gas and Cl2 mixed gas are used to bring hydrogen and fine impurities in the aluminum liquid to the surface of the melt, so as to reduce the gas content of the melt.

[0073] Further, two-stage filtration is used in the step A casting process, including but not limited to: plate CFF filtration + plate CFF filtration, plate CFF filtration + deep bed filtration, plate CFF filtration + tubular filtration, thereby reducing the slag content of the melt, ensuring the purity of the melt, and avoiding the black silk black line caused by the impurity of the melt, and ensuring the surface quality. Al-5Ti-B is used for online refining treatment to ensure the grain size of the aluminum alloy ingot.

[0074] B. After the aluminum alloy ingot is cooled, the head and tail are cut off, and the surface of the ingot is removed by milling;

[0075] C. The ingot after sawing and milling is placed in a push-type heating furnace for soaking, and the metal temperature is 510°C, and the soaking time is 3.5 hours;

[0076] D. The ingot is hot rolled out of the furnace, and the final rolling temperature of the hot rolling is controlled to 330°C, and the hot rolled coil thickness is 2.6mm;

[0077] E. The coil is forcedly cooled, and after cooling to room temperature, cold rolling is carried out to a medium thickness of 0.58mm;

[0078] F. After cold rolling, cleaning and first stretching straightening are carried out, the stretching rate of the first stretching straightening is 0.5%, and then the coil is wound and enters the box annealing furnace for annealing. During the annealing process, protective atmosphere treatment is carried out, the oxygen content is ≤0.3%, the annealing system is that the core of the coil reaches 305°C, and the temperature is kept for 4 hours to reach the complete O state organization, and the coil is cooled to room temperature after intermediate annealing;

[0079] G. The coil is cold rolled to a finished thickness of 0.25mm;

[0080] H. After cold rolling, cleaning and second stretching straightening are carried out, the stretching rate of the second stretching straightening is 0.55%, and then the coil is wound and enters the box annealing furnace for stabilization treatment. The stabilization treatment system is that the core of the coil reaches 185°C, and the temperature is kept for 4 hours, and then cooled to room temperature, and then third stretching straightening is carried out, and the stretching rate of the third stretching straightening is 0.45%;

[0081] I. The 5 series aluminum alloy strip prepared in step H is cut and packaged.

[0082] Comparative Example 1: Conventional 5182 aluminum alloy strip production process

[0083] A. According to the following aluminum alloy mass percentage, smelting, in-furnace refining, online degassing, online filtration are carried out, and then an aluminum alloy ingot is cast.

[0084] Si: 0.078%, Fe: 0.233%, Cu: 0.03%, Mn: 0.312%, Mg: 4.52%; Cr: 0.032%; Zn: 0.018%; Ti: 0.025%, single impurity ≤0.05%, total impurities ≤0.15%, balance Al.

[0085] The smelting process specifically comprises: sequentially feeding the ingredients into a smelting furnace for smelting, and using a flux for refining covering, after feeding, starting stirring after the materials in the furnace are melted, then after refining, slagging, obtaining qualified chemical components, and then using Ar gas and Cl2 mixed gas to bring hydrogen and fine impurities in the aluminum liquid to the surface of the melt, thereby reducing the gas content of the melt.

[0086] Further, a double-stage filtration is used in the step A casting process, including but not limited to: plate CFF filtration + plate CFF filtration, plate CFF filtration + deep bed filtration, plate CFF filtration + pipe filtration, thereby reducing the slag content of the melt, ensuring the purity of the melt, and avoiding the black silk and black line of the material organization caused by the impure melt, and ensuring the surface quality. Al-5Ti-B is used for online refining treatment to ensure the grain size of the aluminum alloy ingot.

[0087] B, after the aluminum alloy ingot is cooled, the head and tail are cut off, and the surface of the ingot is removed by milling;

[0088] C, the ingot after sawing and milling is placed in a push-type heating furnace for soaking, and the metal temperature is 480°C, and the soaking time is 3 hours;

[0089] D, the ingot is hot-rolled out of the furnace, and the final rolling temperature of the hot rolling is controlled to 325°C, and the hot-rolled coil is 5.5 mm thick;

[0090] E, the coil is forcedly cooled, and after cooling to room temperature, cold rolling is performed to a first intermediate thickness of 2.0 mm;

[0091] F, after cold rolling, cleaning is performed, and then the coil is wound and enters a box-type annealing furnace for annealing, a protective atmosphere treatment is performed during the annealing process, the oxygen content is ≤0.3%, and the annealing system is that the core of the coil reaches 305°C, and the soaking time is 4 hours, and a complete O state organization is reached, and after the intermediate annealing, the coil is cooled to room temperature;

[0092] G, after cooling to room temperature, cold rolling is performed to a second intermediate thickness of 0.83 mm;

[0093] H, after cold rolling, cleaning is performed, and then the coil is wound and enters a box-type annealing furnace for annealing, a protective atmosphere treatment is performed during the annealing process, the oxygen content is ≤0.3%, and the annealing system is that the core of the coil reaches 305°C, and the soaking time is 4 hours, and a complete O state organization is reached, and after the intermediate annealing, the coil is cooled to room temperature;

[0094] I. Cold rolling the coiled material to a finished thickness of 0.25 mm;

[0095] J. After cold rolling, cleaning is performed, and then coiling is performed to enter a box-type annealing furnace for stabilization treatment. The stabilization treatment system is that when the core of the coiled material reaches 140°C, the temperature is maintained for 3 hours, and then cooling to room temperature is performed, and then stretch straightening is performed. The stretch rate of the stretch straightening is 0.4%.

[0096] K. The 5-series aluminum alloy strip prepared in step J is cut and packaged.

[0097] Comparative Example 2: using the alloy composition of the present application + traditional production process

[0098] A. Melting, in-furnace refining, on-line degassing, on-line filtering are performed according to the following aluminum alloy mass percentage, and then an aluminum alloy ingot is cast.

[0099] Si: 0.067%, Fe: 0.228%, Cu: 0.083%, Mn: 0.395%, Mg: 5.11%, Cr: 0.026%, Zn: 0.015%, Ti: 0.018%, single impurity ≤0.03%, total impurities ≤0.15%, and the balance is Al.

[0100] The melting process specifically includes: the ingredients are sequentially put into a melting furnace for melting, and a flux is used for refining coverage. After the materials in the furnace are melted, stirring is started, and then refining and slagging are performed. After the qualified chemical composition is obtained, Ar gas and Cl2 mixed gas are used to bring hydrogen and fine impurities in the aluminum liquid to the surface of the melt, so as to reduce the gas content of the melt.

[0101] Further, a double-stage filtering is used in the casting process of step A, including but not limited to: plate type CFF filtering + plate type CFF filtering, plate type CFF filtering + deep bed filtering, and plate type CFF filtering + tube type filtering, so as to reduce the slag content of the melt, ensure the purity of the melt, and avoid the black silk and black line caused by the impure melt, and ensure the surface quality. Al-5Ti-B is used for on-line refining treatment to ensure the grain size of the aluminum alloy ingot.

[0102] B. After the aluminum alloy ingot is cooled, the head and tail are cut off, and the surface of the ingot is milled to remove the condensate layer;

[0103] C. The sawed and milled ingot is placed in a push-type heating furnace for soaking, and the metal temperature is 480°C, and the temperature is maintained for 3 hours;

[0104] D. The ingot is hot-rolled out of the furnace, and the final rolling temperature of the hot rolling is controlled to 325°C, and the hot-rolled coil thickness is 5.5 mm;

[0105] E. The coiled material is forcedly cooled, and after cooling to room temperature, cold rolling is performed to a first intermediate thickness of 2.0 mm.

[0106] F, after cold rolling, cleaning is carried out, and then the coiled material is put into a box-type annealing furnace for annealing. During the annealing process, a protective atmosphere treatment is carried out, and the oxygen content is ≤0.3%. The annealing system is that when the core of the coiled material reaches 305°C, the temperature is kept for 4 hours, so that a complete O-state structure is reached. After the intermediate annealing, the coiled material is cooled to room temperature.

[0107] G, after cooling to room temperature, cold rolling is carried out to a second intermediate thickness of 0.83 mm.

[0108] H, after cold rolling, cleaning is carried out, and then the coiled material is put into a box-type annealing furnace for annealing. During the annealing process, a protective atmosphere treatment is carried out, and the oxygen content is ≤0.3%. The annealing system is that when the core of the coiled material reaches 305°C, the temperature is kept for 4 hours, so that a complete O-state structure is reached. After the intermediate annealing, the coiled material is cooled to room temperature.

[0109] I, the coiled material is cold rolled to a finished thickness of 0.25 mm.

[0110] J, after cold rolling, cleaning is carried out, and then the coiled material is put into a box-type annealing furnace for stabilization treatment. The stabilization treatment system is that when the core of the coiled material reaches 140°C, the temperature is kept for 3 hours, and then the coiled material is cooled to room temperature. Then, the coiled material is subjected to stretch straightening, and the stretch rate of the stretch straightening is 0.4%.

[0111] K, the 5-series aluminum alloy strip prepared in step J is cut and packaged.

[0112] Comparative Example 3: conventional 5182 aluminum alloy composition + production process of the application

[0113] A, according to the following aluminum alloy mass percentage, ingredients are prepared for melting, in-furnace refining, online degassing, online filtering, and then cast into aluminum alloy ingots.

[0114] Si: 0.075%, Fe: 0.239%, Cu: 0.035%, Mn: 0.331%, Mg: 4.55%, Cr: 0.033%, Zn: 0.019%, Ti: 0.024%, single impurity ≤0.05%, total impurities ≤0.15%, and the balance is Al.

[0115] The melting process is as follows: the ingredients are sequentially put into a melting furnace for melting, and a flux is used for refining coverage. After the materials in the furnace are melted, stirring is started, and then refining and slagging are carried out. After the qualified chemical composition is obtained, Ar gas and Cl2 mixed gas are used to bring the hydrogen and fine impurities in the aluminum liquid to the surface of the melt, thereby reducing the gas content of the melt.

[0116] Further, a double-stage filtration is used in the step A casting process, including but not limited to: plate CFF filtration + plate CFF filtration, plate CFF filtration + deep bed filtration, plate CFF filtration + tube filtration, so as to reduce the slag content of the melt, ensure the purity of the melt, and avoid the black silk and black line caused by the impure melt, and ensure the surface quality. Al-5Ti-B is used for online refining treatment to ensure the grain size of the aluminum alloy ingot.

[0117] B. After the aluminum alloy ingot is cooled, the head and tail are cut off, and the surface of the ingot is removed by milling to remove the condensate layer;

[0118] C. The ingot after sawing and milling is placed in a push-type heating furnace for soaking, and the metal temperature is 510°C, and the soaking time is 3.5 hours;

[0119] D. The ingot is hot-rolled out of the furnace, and the final rolling temperature of the hot rolling is controlled to 330°C, and the hot-rolled coil thickness is 2.6mm;

[0120] E. The coil is forcedly cooled, and after cooling to room temperature, cold rolling is performed to a medium thickness of 0.58mm;

[0121] F. After cold rolling, cleaning and first stretch straightening are performed, the stretch rate of the stretch straightening is 0.5%, and then the coil is wound and enters the box annealing furnace for annealing, and a protective atmosphere treatment is performed during the annealing process, and the oxygen content is ≤0.3%, the annealing system is that the core of the coil reaches 305°C, and the soaking time is 4 hours, and the complete O state organization is reached, and after the intermediate annealing, the coil is cooled to room temperature;

[0122] G. The coil is cold-rolled to a finished thickness of 0.25mm;

[0123] H. After cold rolling, cleaning and second stretch straightening are performed, the stretch rate of the stretch straightening is 0.55%, and then the coil is wound and enters the box annealing furnace for stabilization treatment, and the stabilization treatment system is that the core of the coil reaches 185°C, and the soaking time is 4 hours, and then the coil is cooled to room temperature, and third stretch straightening is performed, and the stretch rate of the stretch straightening is 0.45%;

[0124] I. The 5 series aluminum alloy strip prepared in step H is cut and packaged.

[0125] The performance test results of the 5 series-H38 aluminum alloy strips produced in Examples 1-3 are shown in Table 1.

[0126] Table 1 Performance test results of the strip

[0127]

[0128] The performance test results of the 5 series-H38 aluminum alloy strips produced in Comparative Examples 1-3 are shown in Table 2.

[0129] Table 2 Performance test results of the strip

[0130]

[0131] From Table 1, it can be seen that the mechanical properties of the strip samples produced in Examples 1-3 are stable, the elongation is higher, and the bending performance is better. The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art within the technical scope disclosed by the present application, according to the technical scheme and the inventive concept of the present application, equivalent replacement or change, should be covered within the protection scope of the present application.

Claims

1. A method for preparing a 5-series aluminum alloy strip for a vehicle-mounted backlight panel, characterized in that the 5-series aluminum alloy for the vehicle-mounted backlight panel has a composition by mass percentage of Si: ≤0.12%, Fe: 0.2-0.3%, Cu: 0.07-0.09%, Mn: 0.35-0.45%, Mg: 5.05-5.15%, Cr: 0.02-0.04%, Zn: ≤0.03%, Ti: 0.01-0.025%, individual impurities: ≤0.03%, total impurities: ≤0.15%, and the balance being Al. The method for preparing the 5-series aluminum alloy strip for the vehicle-mounted backlight panel comprises the following steps: A. After the aluminum alloy is prepared according to the mass percentage, melting and in-furnace refining are performed, and the aluminum liquid is cast into an aluminum alloy ingot; B. After the aluminum alloy ingot is cooled, the head and tail are cut off, and the surface of the ingot is milled to remove the condensate layer; C. The ingot after sawing and milling is placed in a push-type heating furnace for soaking, with a metal temperature of 480-530°C and a soaking time of 2-5 hours; D. The ingot is hot-rolled after being discharged from the furnace, with a finish rolling temperature of 310-335°C and a hot-rolled coil thickness of 2.2-2.8 mm; E. The coil is forcedly cooled, and after being cooled to room temperature, cold rolling is performed; F. After cold rolling, cleaning and first stretching and straightening are performed, with a stretching rate of 0.3-0.5% for the first stretching and straightening, and then the coil is wound and enters a box-type annealing furnace for annealing, with a protective atmosphere treatment during the annealing process, an oxygen content of ≤0.3%, an annealing schedule of reaching 305°C at the core of the coil, a soaking time of 4 hours, and a completely O-state organization, and cooling to room temperature after intermediate annealing; G. The coil is cold-rolled to a finished thickness; H. After cold rolling, cleaning and second stretching and straightening are performed, with a stretching rate of 0.4-0.6% for the second stretching and straightening, the coil is wound and enters a box-type annealing furnace for stabilization treatment, and after stabilization, the coil is cooled to room temperature, and then third stretching and straightening is performed, with a stretching rate of 0.3-0.5% for the third stretching and straightening; I. The 5-series aluminum alloy strip prepared in step H is cut and packaged. In step E, the cold rolling is performed to an intermediate thickness, and a cold rolling processing rate of 50-60% is reserved from the intermediate thickness to the finished thickness.

2. The method of claim 1, wherein the 5xxx aluminum alloy strip for a vehicle backlight is prepared by the steps of: preparing a 5xxx aluminum alloy strip; and performing a surface treatment on the 5xxx aluminum alloy strip. The intermediate thickness is 0.40-0.75 mm.

3. The method of claim 2, wherein the 5xxx aluminum alloy strip for a vehicle-mounted backlight panel is prepared by the steps of: preparing a 5xxx aluminum alloy strip; and performing a surface treatment on the 5xxx aluminum alloy strip. In step H, the stabilization treatment schedule is that the core of the coil reaches 150-200°C, and the soaking time is 4 hours.

4. The method of claim 2, wherein the 5xxx aluminum alloy strip for a vehicle backlight is prepared by the steps of: preparing a 5xxx aluminum alloy strip; and performing a surface treatment on the 5xxx aluminum alloy strip. ​

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