CN111590041B - Heat treatment method of production device using aluminum-lithium alloy plate - Google Patents

Abstract

The invention discloses a heat treatment method of a production device using an aluminum-lithium alloy plate, which comprises the following steps: s1: feeding the aluminum lithium alloy raw material into a graphite crucible according to a preset mass percentage, heating and smelting to form an aluminum lithium alloy melt, and simultaneously carrying out deoxidization and deslagging treatment on the aluminum lithium alloy melt; s2: the aluminum lithium alloy melt enters a double-roller casting and rolling unit for casting and rolling, and simultaneously a plate blank formed by the double-roller casting and rolling unit enters a finishing rolling unit after passing through a blank drawing straightener and a laminar cooling device and is then conveyed to a cutting device by a conveying device; s3: and (3) placing the finish-rolled plate in a heat treatment furnace for isothermal heat treatment, and cooling the finish-rolled plate to room temperature along with the heat treatment furnace after the heat preservation is finished. According to the invention, the macrosegregation of the aluminum-lithium alloy plate prepared by continuous casting and rolling is greatly reduced, the finish rolling pass is reduced, the mechanical property anisotropy of the plate is reduced, the heat treatment temperature required by the subsequent plate is also reduced, and the heat preservation time is shortened.

Description

Heat treatment method of production device using aluminum-lithium alloy plate

Technical Field

The invention relates to the technical field of aluminum lithium alloy processing and manufacturing, in particular to a heat treatment method of a production device using an aluminum lithium alloy plate.

Background

Aluminum lithium alloys have a reduced specific gravity and increased stiffness compared to conventional aluminum alloys, but maintain high strength, excellent corrosion resistance, fatigue resistance, and ductility of the aluminum alloys, and thus have received great attention from the aerospace industry. However, compared with the conventional aluminum alloy, the metallurgical quality of the aluminum-lithium alloy during smelting and casting is more active than that of the conventional aluminum alloy, and in view of the active chemical property of the lithium element, a plurality of problems such as oxidation, hydrogen absorption, slag inclusion and the like are easy to occur in the smelting process. For example, when the aluminum lithium alloy melt passes through a diversion trench, a crystallizer and other devices, even if the aluminum lithium alloy melt is protected by inert gas, the aluminum lithium alloy melt is difficult to ensure not to be oxidized; meanwhile, in the existing vacuum casting production process, the core part and the surface layer of the aluminum-lithium alloy ingot have large difference of cooling speed, so that serious macro component segregation exists in different areas of the ingot, therefore, the ingot has to be processed into a thin plate material by multi-pass large plastic deformation in the later period, and long-time and multi-stage heat treatment is assisted to eliminate the performance difference of the plate material in different areas caused by the component segregation.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems that oxidation, hydrogen absorption, slag inclusion and the like are easy to occur in the smelting process of the conventional aluminum lithium alloy smelting and casting, the invention provides a heat treatment method of a production device using an aluminum lithium alloy plate.

The technical scheme is as follows: in order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows:

the heat treatment method of the production device using the aluminum lithium alloy plate adopts the following production device of the aluminum lithium alloy plate, the production device comprises a graphite crucible, a tundish, a circulating nitrogen protection box body, a cutting device and a conveying device, a metal melt liquid level height monitoring and controlling device is installed inside the tundish and used for ensuring that the melt liquid level inside the tundish is kept within a preset height range, a ceramic stopper rod is installed inside the tundish, two ends of the ceramic stopper rod are connected with flow guide grooves in a penetrating manner, and SiO (silicon dioxide) is arranged inside the tundish₂-CaO-Al₂O₃The upper end of the tundish is connected with the lower end of the graphite crucible through a diversion trench at one end of the ceramic stopper rod, and SiO is arranged in the graphite crucible₂-CaO-Al₂O₃Slag, the two sides of the graphite crucible are both provided withThe device is provided with a medium-frequency induction heater, the medium-frequency induction heater is used for controlling the temperature inside the graphite crucible, and the lower end of the tundish is connected with a crystallizer through a diversion trench at the other end of the ceramic stopper rod;

the device comprises a circulating nitrogen gas protection box body, a double-roller casting and rolling unit, a finish rolling unit, at least one group of blank drawing straightener and a laminar cooling device, at least one group of blank drawing straightener and laminar cooling device, a conveying device, a cutting device and a conveying device, wherein the circulating nitrogen gas protection box body is arranged at the lower end of a crystallizer, the double-roller casting and rolling unit is arranged in the circulating nitrogen gas protection box body, a feed inlet of the double-roller casting and a discharge outlet of the double-roller casting and rolling unit are connected, the discharge outlet of the double-roller casting and rolling unit is connected with the discharge outlet of the crystallizer, the discharge outlet of the double-roller casting and rolling unit is connected with the finish rolling unit through the blank drawing straightener and the laminar cooling device;

a heat treatment method of a production device using an aluminum-lithium alloy plate specifically comprises the following steps:

s1: feeding the aluminum lithium alloy raw material into a graphite crucible according to a preset mass percentage for heating and smelting, and heating and smelting in the SiO₂-CaO-Al₂O₃Forming an aluminum lithium alloy melt under the action of the molten slag, simultaneously carrying out deoxidization and deslagging treatment on the aluminum lithium alloy melt, and leading the aluminum lithium alloy melt into the tundish from the inside of the graphite crucible through the diversion trench, wherein the preset mass percentages are as follows: 2.3 to 5.2 percent of Cu, 0.8 to 2.5 percent of Li, 0.4 to 0.6 percent of Zn, 0.2 to 0.4 percent of Mn, 0.25 to 0.9 percent of Mg, 0.1 to 0.2 percent of Zr, Ti<0.1％、Fe<0.2％、Si<0.1 percent, and the balance of Al, and the smelting temperature range in the graphite crucible is as follows: 700-750 ℃, and the temperature rise speed is as follows: 10-20 ℃/min, wherein the temperature maintaining range of the aluminum lithium alloy melt inside the tundish is as follows: 680-720 ℃;

s2: the aluminum lithium alloy melt in the tundish enters a double-roller casting and rolling unit through a crystallizer for casting and rolling, and simultaneously passes through the double-roller casting and rollingThe slab formed by the unit enters the finishing mill unit after the straightening treatment of a blank drawing straightener and the cooling treatment of a laminar cooling device, and is conveyed to a cutting device by the conveying device, and the slab is cut into finishing rolled plates with different sizes and specifications by the cutting device, wherein the SiO is₂-CaO-Al₂O₃The slag is used for carrying out oxygen removal and slag removal treatment on the aluminum-lithium alloy melt, and the starting temperature range of the double-roller casting and rolling unit is as follows: 650-700 ℃, and the termination temperature range is as follows: the continuous rolling blank speed range is 150-200 ℃ as follows: 200-1000 mm/min, the starting thickness range is: 35-45 mm, the final thickness range is: 7-10 mm, wherein the rolling reduction range of each pass is as follows: 20-50%, laminar cooling device's laminar cooling speed range is: 10-20 ℃/s;

s3: and placing the finish-rolled plate in a heat treatment furnace for isothermal heat treatment, cooling the finish-rolled plate to room temperature along with the heat treatment furnace after the heat treatment is finished, and sampling along the parallel rolling direction and the vertical rolling direction of the finish-rolled plate to perform tensile experiment tests.

Has the advantages that: compared with the prior art, the technical scheme of the invention has the following beneficial technical effects:

according to the invention, the macrosegregation of the aluminum-lithium alloy plate prepared by continuous casting and rolling is greatly reduced, the finish rolling pass is reduced, the mechanical property anisotropy of the plate is reduced, meanwhile, the heat treatment temperature required by the subsequent plate is also reduced, and the heat preservation time is shortened, so that the process flow is obviously shortened integrally, the energy is saved, and the cost is reduced.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus for producing an aluminum-lithium alloy sheet according to the present invention;

FIG. 2 is a schematic diagram of a mechanical tensile test sample of an aluminum-lithium alloy continuous casting and rolling slab of the invention;

part names corresponding to reference numbers in the drawings:

3. a graphite crucible; 4. a medium frequency induction heater; 5. a ceramic stopper rod; 6. a tundish; 7. a crystallizer; 8. a device for monitoring and controlling the liquid level of the molten metal; 9. a diversion trench; 12. a twin roll casting and rolling mill train; 13. circulating a nitrogen protection box body; 14. a throwing straightener; 15. a laminar flow cooling device; 16. a finishing mill group; 17. a cutting device; 18. and a conveying device.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the drawings in the embodiments of the present invention are combined below to clearly and completely describe the technical solutions in the embodiments of the present invention. The described embodiments are some, but not all embodiments of the invention. Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.

It should be noted that, in the description of the present invention, the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of description and simplification of the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

Further, it will be appreciated that the dimensions of the various elements shown in the figures are not drawn to scale, for ease of description, and that the thickness or width of some layers may be exaggerated relative to other layers, for example.

It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined or illustrated in one figure, it will not need to be further discussed or illustrated in detail in the description of the following figure.

Example 1

Referring to fig. 1, the present embodiment provides an apparatus for producing an aluminum-lithium alloy sheet, which includes a graphite crucible 3, a tundish 6, a crystallizer 7, a twin roll casting and rolling mill group 12, a circulating nitrogen gas protection box 13, a billet straightener 14, a laminar cooling device 15, a finishing mill group 16, a cutting device 17, and a conveying device 18. Wherein the internally mounted of middle package 6 has ceramic stopper 5 and metal melt liquid level height monitoring and controlling means 8, and the both ends of this ceramic stopper 5 all run through the connection have guiding gutter 9, and in this embodiment, the upper end of middle package 6 is connected with graphite crucible 3's lower extreme through the guiding gutter 9 of 5 one ends of ceramic stopper, and the lower extreme of middle package 6 is connected with crystallizer 7 through the guiding gutter 9 of 5 other ends of ceramic stopper. Specifically, the metal melt liquid level monitoring and controlling device 8 is used for flowing the aluminum lithium alloy solution into the tundish 6, and the ceramic stopper 5 is used for opening when the aluminum lithium alloy solution reaches a preset height so as to allow the aluminum lithium alloy solution to flow out. Wherein, the ceramic stopper rod 5 and the metal melt liquid level monitoring and controlling device 8 have a synergistic relationship, which is mainly used for ensuring that the melt liquid level inside the tundish 6 is kept at a stable height, thereby ensuring the stable flow rate of the aluminum-lithium alloy solution.

In the present embodiment, medium frequency induction heaters 4 are installed on both sides of the graphite crucible 3, and the medium frequency induction heaters 4 are used to control the temperature inside the graphite crucible 3. Meanwhile, SiO is arranged in the graphite crucible 3₂-CaO-Al₂O₃SiO is also provided in the slag and the tundish 6₂-CaO-Al₂O₃And (3) slag.

The circulating nitrogen protection box body 13 is arranged at the lower end of the crystallizer 7, the double-roller casting and rolling unit 12 is arranged in the circulating nitrogen protection box body 13, a feed inlet of the double-roller casting and rolling unit 12 is connected with a discharge outlet of the crystallizer 7, the discharge outlet of the double-roller casting and rolling unit 12 is connected with a finishing mill unit 16 through a billet straightener 14 and a laminar cooling device 15, and the finishing mill unit 16 is connected with a conveying device 18 through a cutting device 17. It is to be noted that the discharge port of the twin roll caster 12, the inlet and outlet of the leveler 14, and the inlet of the laminar cooling apparatus 15 are located on the same horizontal plane.

Specifically, at least one set of the leveler 14 and the laminar cooling device 15 is provided between the twin roll casting mill group 12 and the finishing mill group 16, and at least one set of the leveler 14 and the laminar cooling device 15 is provided in sequence/spaced apart. That is, the number of the bloom straighteners 14 and the number of the laminar cooling devices 15 are not specifically selected, and are determined according to actual conditions, and similarly, the positional relationship between the bloom straighteners 14 and the laminar cooling devices 15 is not unique, and when a plurality of groups are provided, the bloom straighteners can be placed in sequence, or can be placed at intervals, and there is no specific requirement. Wherein the pull straightener 14 can keep the sheet unbent and the sheet straight. The laminar cooling device 15 cools the plate to perform the following cold finish rolling.

Referring to fig. 2, the present embodiment also provides a heat treatment method using a production apparatus for an aluminum-lithium alloy sheet, specifically including the steps of:

step S1: feeding the aluminum lithium alloy raw material into a graphite crucible 3 according to a preset mass percentage for heating and smelting, wherein the preset mass percentage specifically comprises the following steps: 2.3 to 5.2 percent of Cu, 0.8 to 2.5 percent of Li, 0.4 to 0.6 percent of Zn, 0.2 to 0.4 percent of Mn, 0.25 to 0.9 percent of Mg, 0.1 to 0.2 percent of Zr, less than 0.1 percent of Ti, less than 0.2 percent of Fe, less than 0.1 percent of Si, and the balance of Al. In this embodiment, the preset mass percentages are specifically set and selected as follows: 3.85% Cu, 1.50% Li, 0.46% Zn, 0.30% Mn, 0.45% Mg, 0.13% Zr, 0.06% Ti, 0.08% Fe, 0.05% Si, and the balance Al.

Wherein the smelting temperature range in the graphite crucible 3 is as follows: 700-750 ℃, and the temperature rise speed is as follows: 10 to 20 ℃/min. In this embodiment, the temperature of the graphite crucible 3 is raised from room temperature to 700 ℃ at a constant rate, and the heating rate is 10 ℃/min.

While in SiO₂-CaO-Al₂O₃Forming aluminum lithium alloy melt under the action of the slag, and carrying out oxygen removal and slag removal treatment on the aluminum lithium alloy melt, wherein SiO is₂-CaO-Al₂O₃The slag can also be used for carrying out oxygen removal and slag removal treatment on the aluminum lithium alloy melt. After preliminary oxygen removal and slag removal, the mixture is introduced into the tundish 6 from the inside of the graphite crucible 3 through the guide groove 9 and then introduced into the SiO inside the tundish 6₂-CaO-Al₂O₃The molten slag is used for carrying out the treatment on the aluminum lithium alloy meltAnd removing oxygen and slag again. Wherein the temperature holding range of the aluminum lithium alloy melt inside the tundish 6 is as follows: 680-720 ℃.

Step S2: the aluminum lithium alloy melt in the tundish 6 enters a double-roller casting-rolling mill group 12 through a crystallizer 7 for casting, wherein the starting temperature range of the double-roller casting-rolling mill group 12 is as follows: 650-700 ℃, namely the temperature range when the aluminum lithium alloy melt enters the double-roller casting and rolling unit 12 is as follows: 650-700 ℃. The termination temperature range is: the temperature of the aluminum lithium alloy melt discharged from the twin-roll casting and rolling unit 12 is 150-200 ℃, namely the temperature range is as follows: 150 to 200 ℃. The continuous rolling blank speed range is as follows: 200 to 1000 mm/min. The starting thickness range is: 35-45 mm, namely the thickness range of the aluminum lithium alloy melt before entering the double-roller casting and rolling unit 12 is as follows: 35-45 mm. The final thickness range is: 7-10 mm, namely the thickness range of the aluminum lithium alloy melt before exiting the double-roller casting and rolling unit 12 is as follows: 8-10 mm. The rolling reduction rate range of each pass is as follows: 20 to 50 percent. In this example, the twin roll caster set 12 was started at 650 ℃, stopped at 200 ℃, rolled at a billet speed of 650mm/min, started at 35mm, stopped at 7mm, and rolled at a reduction of 35% per pass.

Meanwhile, the slab formed by the twin-roll casting and rolling mill group 12 enters the finishing mill group 16 after being straightened by the blank straightening device 14 and cooled by the laminar cooling device 15, wherein the laminar cooling speed range of the laminar cooling device 15 is as follows: 10-20 ℃/s. The thickness range of the rolled slab of the finishing mill 16 is: 7-10 mm, namely the thickness range before rolling the plate blank is as follows: 8-10 mm. The final rolling thickness range is as follows: 2-2.5 mm, namely the thickness range of the plate blank after rolling by the finishing mill group 16 is as follows: 2-2.5 mm. The rolling reduction rate of each pass is less than 20 percent. In this example, the thickness of the 16-entry rolled slab of the finishing mill group was 7mm, the thickness of the final rolling was 2mm, and the rolling reduction per pass was 20%.

And then conveyed to a cutting device 17 by a conveying device 18, and cut into finish rolled plates with different dimensions by the cutting device 17.

Step S3: and (3) placing the finish-rolled plate in a heat treatment furnace for isothermal heat treatment, specifically, performing isothermal heat treatment at the temperature of 135-165 ℃ for 30-60 hours, cooling the finish-rolled plate to room temperature along with the heat treatment furnace after the heat treatment is finished, and sampling along the parallel rolling direction and the vertical rolling direction of the finish-rolled plate to perform tensile test.

In this example, a finish rolled plate was placed in a heat treatment furnace, isothermal heat treatment was carried out at 165 ℃ for 60 hours, the plate was cooled to room temperature with the furnace after the completion of heat preservation, and samples were taken in the directions parallel to the rolling direction and the direction perpendicular to the rolling direction of the plate to conduct tensile test tests on a standard mechanical sample. Wherein the test result of the tensile test is as follows: the yield strength in the parallel rolling direction is 320MPa, the tensile strength is 480MPa, and the elongation at break is 10 percent; the yield strength in the vertical rolling direction was 315MPa, the tensile strength was 475MPa, and the elongation at break was 9.4%.

Example 2

Embodiment 2 provides a heat treatment method using a production apparatus for an aluminum-lithium alloy sheet, which has the same structure and method steps as those of embodiment 1, except that the specific setting of the preset mass percentages is: 2.7% of Cu, 2.1% of Li, 0.60% of Zn, 0.30% of Mn, 0.3% of Mg, 0.05% of Zr, 0.08% of Ti, 0.06% of Fe, 0.02% of Si and the balance of Al.

The temperature of the graphite crucible 3 is increased to 720 ℃ from room temperature at a constant speed, and the temperature increasing speed is 15 ℃/min.

The starting temperature of the twin-roll casting and rolling unit 12 is 680 ℃, the finishing temperature is 160 ℃, the continuous rolling blank speed is 680mm/min, the starting thickness is 40mm, the finishing thickness is 9mm, and the rolling reduction rate of each pass is 45%.

The thickness of a 16-entry rolling plate blank of the finishing mill group is 8mm, the thickness of the final rolling is 2.5mm, and the rolling reduction rate of each pass is 15%.

In this example, a finish rolled plate was placed in a heat treatment furnace, isothermal heat treatment was carried out at 135 ℃ for 45 hours, the plate was cooled to room temperature with the furnace after the completion of heat preservation, and samples were taken in the directions parallel to the rolling direction and the direction perpendicular to the rolling direction of the plate to conduct tensile test of a standard mechanical sample. Wherein the test result of the tensile test is as follows: the yield strength in the parallel rolling direction is 332MPa, the tensile strength is 520MPa, and the elongation at break is 8.0 percent; the yield strength in the vertical rolling direction is 327MPa, the tensile strength is 507MPa, and the elongation at break is 7.8%.

Example 3

Embodiment 3 provides a heat treatment method using a production apparatus for an aluminum-lithium alloy sheet, which has the same structure and method steps as those of embodiment 1, except that the specific setting of the preset mass percentages is: 4.2% Cu, 1.2% Li, 0.24% Zn, 0.23% Mn, 0.90% Mg, 0.14% Zr, 0.03% Ti, 0.14% Fe, 0.05% Si, and the balance Al.

The temperature of the graphite crucible 3 is increased to 750 ℃ from room temperature at a constant speed, and the temperature increasing speed is 10 ℃/min.

The starting temperature of the twin-roll casting and rolling unit 12 is 700 ℃, the finishing temperature is 150 ℃, the continuous rolling blank speed is 750mm/min, the starting thickness is 45mm, the finishing thickness is 9mm, and the rolling reduction rate of each pass is 50%.

The thickness of a 16-entry rolling plate blank of the finishing mill group is 8mm, the thickness of the final rolling is 2.3mm, and the rolling reduction rate of each pass is 15%.

In this example, a finish rolled plate was placed in a heat treatment furnace, isothermal heat treatment was carried out at 155 ℃ for 30 hours, the plate was cooled to room temperature with the furnace after the completion of heat preservation, and samples were taken in the directions parallel to the rolling direction and the direction perpendicular to the rolling direction of the plate to conduct tensile test tests of a standard mechanical sample. Wherein the test result of the tensile test is as follows: the yield strength in the parallel rolling direction is 412MPa, the tensile strength is 512MPa, and the elongation at break is 8.2%; the yield strength in the vertical rolling direction was 424MPa, the tensile strength was 500MPa, and the elongation at break was 7.9%.

The present invention and its embodiments have been described in an illustrative manner, and are not to be considered limiting, as illustrated in the accompanying drawings, which are merely exemplary embodiments of the invention and not limiting of the actual constructions and methods. Therefore, if the person skilled in the art receives the teaching, the structural modes and embodiments similar to the technical solutions are not creatively designed without departing from the spirit of the invention, and all of them belong to the protection scope of the invention.

Claims (1)

1. A heat treatment method using a production device of an aluminum-lithium alloy plate is characterized in that,the heat treatment method adopts a production device of the following aluminum-lithium alloy plate, the production device comprises a graphite crucible (3), a tundish (6), a circulating nitrogen protection box body (13), a cutting device (17) and a conveying device (18), a metal melt liquid level height monitoring and controlling device (8) is arranged inside the tundish (6), the metal melt liquid level height monitoring and controlling device (8) is used for ensuring that the melt liquid level inside the tundish (6) is kept within a preset height range, meanwhile, a ceramic stopper rod (5) is arranged inside the tundish (6), two ends of the ceramic stopper rod (5) are respectively connected with a flow guide groove (9) in a penetrating manner, and SiO (silicon dioxide) is arranged inside the tundish (6)₂-CaO-Al₂O₃The upper end of the tundish (6) is connected with the lower end of the graphite crucible (3) through a diversion trench (9) at one end of the ceramic stopper rod (5), and SiO is arranged in the graphite crucible (3)₂-CaO-Al₂O₃The device comprises slag, wherein medium-frequency induction heaters (4) are respectively arranged on two sides of a graphite crucible (3), the medium-frequency induction heaters (4) are used for controlling the temperature inside the graphite crucible (3), and the lower end of a tundish (6) is connected with a crystallizer (7) through a flow guide groove (9) at the other end of a ceramic stopper rod (5);

the circulating nitrogen protection box body (13) is arranged at the lower end of the crystallizer (7), a double-roller casting and rolling unit (12) is arranged in the circulating nitrogen protection box body (13), a feed inlet of the double-roller casting and rolling unit (12) is connected with a discharge outlet of the crystallizer (7), the discharge outlet of the double-roller casting and rolling unit (12) is connected with a finishing mill unit (16) through a blank drawing straightener (14) and a laminar flow cooling device (15), at least one group of blank drawing straightener (14) and a laminar flow cooling device (15) are arranged between the double-roller casting and rolling unit (12) and the finishing mill unit (16), at least one group of blank drawing straightener (14) and a laminar flow cooling device (15) are sequentially/alternately arranged, and the discharge outlet of the double-roller casting and rolling unit (12), and an inlet and an outlet of the blank drawing straightener (14), The inlets of the laminar cooling device (15) are positioned on the same horizontal plane, and the finishing mill group (16) is connected with a conveying device (18) through a cutting device (17);

the heat treatment method specifically comprises the following steps:

s1: aluminum lithium is addedThe alloy raw materials are fed into a graphite crucible (3) according to the preset mass percentage for heating and smelting, and SiO is added₂-CaO-Al₂O₃Forming an aluminum lithium alloy melt under the action of the molten slag, simultaneously carrying out deoxidization and deslagging treatment on the aluminum lithium alloy melt, and leading the aluminum lithium alloy melt into the interior of a tundish (6) from the interior of a graphite crucible (3) through a diversion trench (9), wherein the preset mass percentages are as follows: 2.3 to 5.2 percent of Cu, 0.8 to 2.5 percent of Li, 0.4 to 0.6 percent of Zn, 0.2 to 0.4 percent of Mn, 0.25 to 0.9 percent of Mg, 0.1 to 0.2 percent of Zr, Ti<0.1％、Fe<0.2％、Si<0.1 percent, and the balance of Al, and the smelting temperature range in the graphite crucible (3) is as follows: 700-750 ℃, and the temperature rise speed is as follows: 10-20 ℃/min, wherein the temperature maintaining range of the aluminum lithium alloy melt in the tundish (6) is as follows: 680-720 ℃;

s2: the aluminum lithium alloy melt in the tundish (6) enters a double-roller casting and rolling unit (12) through a crystallizer (7) for casting and rolling, meanwhile, a plate blank formed by the double-roller casting and rolling unit (12) enters a finishing mill unit (16) after being straightened by a blank drawing straightener (14) and cooled by a laminar cooling device (15), and then is conveyed to a cutting device (17) through a conveying device (18), the cutting device (17) cuts the plate blank into finishing rolled plates with different sizes and specifications, and the SiO is₂-CaO-Al₂O₃The slag is used for carrying out oxygen removal and slag removal treatment on the aluminum-lithium alloy melt, and the starting temperature range of the double-roller casting and rolling unit (12) is as follows: 650-700 ℃, and the termination temperature range is as follows: the continuous rolling blank speed range is 150-200 ℃ as follows: 200-1000 mm/min, the starting thickness range is: 35-45 mm, the final thickness range is: 7-10 mm, wherein the rolling reduction range of each pass is as follows: 20-50%, laminar cooling device (15) laminar cooling speed range is: 10-20 ℃/s;

s3: and placing the finish-rolled plate in a heat treatment furnace for isothermal heat treatment, cooling the finish-rolled plate to room temperature along with the heat treatment furnace after the heat treatment is finished, and sampling along the parallel rolling direction and the vertical rolling direction of the finish-rolled plate to perform tensile experiment tests.

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