A method for rolling a ti80 titanium alloy sheet

Abstract

This invention discloses a rolling method for Ti80 titanium alloy thin plates. The rolling method includes the following steps: 1. Rolling in a first heat to obtain a first rolled slab; 2. Cutting to obtain a first intermediate slab; 3. Rolling in a second heat to obtain a second rolled slab; 4. Cutting to obtain a second intermediate slab; 5. Rolling in a third heat to obtain a third rolled slab; 6. Cutting to obtain a third intermediate slab; 7. Covering with a steel clasp to obtain a covered lap-rolled ladle; 8. Rolling in a fourth heat, then unpacking, and finally performing shaping annealing to obtain the Ti80 titanium alloy thin plate. This rolling method, by controlling the rolling temperature at different heats and employing reversing cross-rolling between heats, combined with online reheating in the furnace, reduces the significant cracking of titanium alloys caused by temperature drops in traditional processes. It produces Ti80 titanium alloy thin plates with uniform and fine equiaxed α grains in the microstructure and meeting mechanical property requirements, suitable for shipbuilding, machinery, chemical, and petroleum industries.

Description

Technical Field

[0001] This invention belongs to the field of titanium and titanium alloy sheet preparation technology, and in particular relates to a rolling method for Ti80 titanium alloy thin sheet. Background Technology

[0002] Ti80 is a near-α titanium alloy with a nominal composition of Ti-6Al-2Zr-3Nb-1Mo (wt.%). Due to its high strength, excellent corrosion resistance and good weldability, it is widely used in shipbuilding, machinery, chemical and petroleum industries.

[0003] The mechanical properties of Ti80 alloys are greatly influenced by their microstructure, such as the volume fraction and morphology of α and β phases, grain size and orientation, and the distribution of strengthening precipitates. Furthermore, the microstructure of Ti80 alloys is significantly affected by heat treatment processes. Current research on Ti80 mainly focuses on bars, tubes, and thick plates; research on the rolling and heat treatment of thin Ti80 alloy plates has not yet been found. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a rolling method for Ti80 titanium alloy thin plates. This rolling method, by controlling the rolling temperature at different heat passes and employing reversible cross-rolling between different heat passes, combined with online reheating in the furnace, reduces the significant cracking of titanium alloys caused by temperature drops in traditional processes, thus producing Ti80 titanium alloy thin plates with uniform and fine equiaxed α grains in the microstructure and meeting the required mechanical properties.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a rolling method for Ti80 titanium alloy thin plates, characterized by comprising the following steps: Step 1: A Ti80 titanium alloy slab with a thickness of 150mm~180mm, a width of 1800mm~2100mm, and a length of 1200mm~1400mm is rolled in a first pass at 935℃~985℃ and then reheated in an online furnace to obtain a first rolled slab with a thickness of 45mm~60mm and a width of 1800mm~2100mm. The first pass rolling is unidirectional rolling, with a pass deformation rate of 4%~13% and a rolling speed of 3m / s~4m / s. Step 2: Cut the first rolled slab obtained in Step 1 to obtain multiple first intermediate slabs; Step 3: The first intermediate slab obtained in Step 2 is subjected to a second rolling process at 915℃~965℃, and then returned to the furnace for reheating online to obtain a second rolled slab with a thickness of 17mm~20mm and a width of 1800mm~2100mm. The deformation rate of the second rolling pass is 12%~17%, the rolling speed is 3m / s~4m / s, and the rolling direction is the same as that of the first rolling process in Step 1. Step 4: Cut the second rolled slab obtained in Step 3 to obtain multiple second intermediate slabs; Step 5: The second intermediate slab obtained in Step 4 is rolled for a third time at 895℃~945℃, and then returned to the furnace for reheating online to obtain a third rolled slab with a thickness of 10mm~12mm and a width of 1500mm~1800mm; the deformation rate of the third rolling pass is 9%~14%, the rolling speed is 3m / s~4m / s, and the rolling direction is perpendicular to the rolling direction of the second rolling in Step 3; Step 6: Cut the third rolled slab obtained in step 5 to obtain multiple third intermediate slabs; Step 7: After coating the surface of the third intermediate slab obtained in Step 6 with an anti-oxidation coating, select several sheets and stack them, then wrap them with a steel clasp to obtain a wrapped and stacked ladle. Step 8: The cladding and rolled ladle obtained in Step 7 is subjected to a fourth rolling process at 875℃~925℃. After uncoating, it is annealed at 765℃~835℃ to obtain a Ti80 titanium alloy sheet with a thickness of 2mm~4mm and a width of 1500mm~1800mm. The deformation rate of the fourth rolling pass is 7%~21%, the rolling speed is 3m / s~4m / s, and the rolling direction is the same as that of the third rolling process in Step 5.

[0006] This invention obtains Ti80 titanium alloy thin plates by sequentially performing a first rolling, cutting, a second rolling, cutting, a third rolling, cutting, and a fourth rolling. It utilizes the principle that different rolling temperatures, deformation rates, and rolling directions of the Ti80 titanium alloy can avoid grain coarsening and the "hereditary" nature of the microstructure, resulting in a fine and uniform microstructure. The invention employs two-stage reversing cross-rolling, combined with timely temperature replenishment in the heating furnace, and cuts intermediate slabs of the designed width after the intermediate rolling stage. The method of subsequent rolling and precise control of the deformation rate and rolling speed of each rolling pass avoids the phenomena of plate chipping and cracking caused by the strong processing texture of single-phase titanium alloy after reversal rolling. It also reduces the obvious cracking of titanium alloy caused by temperature drop in traditional processes, while reducing the number of rolling passes and shortening the production cycle by 10-15 days, saving costs and reducing the difficulty of the production process. Furthermore, through reasonable shearing and blanking design, it is possible to produce Ti80 titanium alloy thin plates of various thicknesses from a single titanium alloy slab, thereby improving production efficiency. Meanwhile, this invention utilizes the characteristic that Ti80 titanium alloy is a near-α alloy, and controls the rolling temperature of each rolling pass to be below the phase transformation point, to prepare finished Ti80 titanium alloy thin plates with uniform and fine equiaxed α grains in the metallographic structure, thereby meeting the mechanical property requirements.

[0007] The above-mentioned rolling method for Ti80 titanium alloy thin plate is characterized in that, in step one, an anti-oxidation coating is applied to the surface of the Ti80 titanium alloy slab before the first rolling, the final rolling temperature of the first rolling is not lower than 750°C, and the total deformation rate of the first rolling is 60%~75%.

[0008] The above-mentioned rolling method for Ti80 titanium alloy thin plate is characterized in that, in step three, an anti-oxidation coating is applied to the surface of the first intermediate slab before the second rolling, the final rolling temperature of the second rolling is not lower than 400℃, and the total deformation rate of the second rolling is 60%~70%; the thickness of the first intermediate slab is 45mm~60mm, the width is 1800mm~2100mm, and the length is 1050mm~1500mm.

[0009] The above-mentioned rolling method for Ti80 titanium alloy thin plate is characterized in that, before the third rolling in step five, an anti-oxidation coating is applied to the surface of the second intermediate slab; the final rolling temperature of the third rolling is not lower than 400℃; and the total deformation rate of the third rolling is 35%~50%. The thickness of the second intermediate slab is 17mm~20mm, the width is 1800mm~2100mm, and the length is 1500mm~1800mm.

[0010] The above-mentioned rolling method for Ti80 titanium alloy thin plate is characterized in that the thickness of the third intermediate slab in step six is ​​10mm~12mm, the width is 1500mm~1800mm, and the length is 900mm~1100mm.

[0011] The above-mentioned rolling method for Ti80 titanium alloy thin plate is characterized in that the steel cladding in step seven includes upper and lower cover steel plates and side sealing steel plates, the steel cladding has vent holes at both ends, and the ratio of the total thickness of the third intermediate slab in the cladding ladle to the thickness of the upper and lower cover steel plates is 0.6~1.

[0012] This invention prevents gas expansion and bulging during hot rolling by setting vent holes at both ends of the steel ladle sleeve; and avoids the upper and lower cover steel plates being too thin, which would cause the third intermediate slab to easily penetrate the steel plate after rolling by setting the thickness ratio to 0.6~1, and avoids the upper and lower cover steel plates being too thick, which would make it difficult to control the rolling thickness of the third intermediate slab.

[0013] The above-mentioned rolling method for Ti80 titanium alloy thin plate is characterized in that the final rolling temperature of the fourth rolling in step eight is not lower than 700°C, and the total deformation rate of the fourth rolling is 60%~80%.

[0014] This invention effectively reduces surface cracks and improves surface quality of the sheet by controlling the final rolling temperature and total deformation rate of each rolling pass.

[0015] The above-mentioned rolling method for Ti80 titanium alloy thin plate is characterized in that the thickness of the anti-oxidation coating is 1mm~2mm.

[0016] This invention effectively reduces the oxide scale generated during prolonged heating of slabs by controlling the thickness of the anti-oxidation coating.

[0017] Compared with the prior art, the present invention has the following advantages: 1. This invention reduces the significant cracking of titanium alloys caused by temperature drop in traditional processes by using reversible cross rolling between different heat treatments, combined with timely temperature replenishment in the heating furnace, and cutting intermediate slabs after intermediate heat treatment to obtain the finished width for subsequent rolling. This reduces the number of rolling heat treatments and shortens the production cycle by 10-15 days, saving costs and reducing the difficulty of the production process.

[0018] 2. This invention prepares Ti80 titanium alloy thin plates with uniform and fine equiaxed α grains in the metallographic structure and thus meet the mechanical property requirements by controlling the rolling temperature of each rolling pass to be below the phase transformation point.

[0019] 3. While ensuring the production of Ti80 titanium alloy thin plates, this invention uses a single titanium alloy slab to produce finished plates of various widths and specifications. This fully utilizes the slab and overcomes the shortcomings of traditional production processes where a single slab can only produce one specification of finished plate, thereby improving the production efficiency of Ti80 titanium alloy thin plates.

[0020] 4. By employing a wrapping rolling method for the fourth rolling process, this invention can effectively ensure temperature uniformity during rolling, resulting in more stable performance of finished products in the same batch.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 Metallographic image (200×) of the Ti80 titanium alloy thin plate prepared in Example 1 of this invention.

[0023] Figure 2 Metallographic image (200×) of the Ti80 titanium alloy thin plate prepared in Example 2 of the present invention.

[0024] Figure 3 Metallographic image (200×) of the Ti80 titanium alloy thin plate prepared in Example 3 of the present invention. Detailed Implementation

[0025] Example 1 This embodiment includes the following steps: Step 1: The Ti80 titanium alloy slab is rolled in the first pass at 935℃~965℃, and then reheated in the furnace online to obtain the first rolled slab. The Ti80 titanium alloy slab has a thickness of 150mm, a width of 1800mm, and a length of 1400mm. The first pass is a unidirectional rolling process with 10 passes. The deformation rates for each pass are 4%, 7%, 10%, 13%, 11.5%, 11%, 10%, 8%, 7%, and 6%, respectively. The slab is reheated in the furnace for 60 minutes after the fifth pass. The total deformation rate of the first pass is 60%, the rolling speed is 3m / s, and the final rolling temperature is not lower than 750℃. Before the first pass, a 1mm thick anti-oxidation coating of GZH-4 paint is applied to the surface of the Ti80 titanium alloy slab. The first rolled slab has a thickness of 60mm and a width of 1800mm. Step 2: Cut the first rolled slab obtained in Step 1 to obtain multiple first intermediate slabs; the thickness of the first intermediate slab is 60mm, the width is 1800mm, and the length is 1050mm. Step 3: The first intermediate slab obtained in Step 2 is subjected to a second rolling process at 915℃~945℃, and then reheated in the furnace online to obtain the second rolled slab. The second rolling process consists of 7 passes, with the following deformation rates for each pass: 12%, 13%, 17%, 17%, 16%, 13%, and 13%, respectively, for a total deformation rate of 67%. The rolling speed is 3 m / s, and the final rolling temperature is not lower than 400℃. The rolling direction of the second rolling process is the same as that of the first rolling process in Step 1. Before the second rolling process, a 1 mm thick anti-oxidation coating of GZH-4 paint is applied to the surface of the first intermediate slab. The second rolled slab has a thickness of 20 mm and a width of 1800 mm. Step 4: Cut the second rolled slab obtained in Step 3 to obtain multiple second intermediate slabs; the thickness of the second intermediate slab is 20mm, the width is 1800mm, and the length is 1500mm. Step 5: The second intermediate slab obtained in Step 4 is subjected to a third rolling process at 895℃~925℃, and then reheated in the furnace online to obtain the third rolled slab. The third rolling process consists of 5 passes, with the deformation rates of each pass being 9%, 14%, 12.5%, 14%, and 14%, respectively, for a total deformation rate of 50%. The rolling speed is 3m / s, and the final rolling temperature is not lower than 400℃. The rolling direction of the third rolling process is perpendicular to the rolling direction of the second rolling process in Step 3. Before the third rolling process, a 1mm thick anti-oxidation coating of GZH-4 paint is applied to the surface of the second intermediate slab. The thickness of the third rolled slab is 10mm, and the width is 1500mm. Step 6: Cut the third rolled slab obtained in Step 5 to obtain multiple third intermediate slabs; the thickness of the third intermediate slab is 10mm, the width is 1500mm, and the length is 1100mm. Step 7: After coating the surface of the third intermediate slab obtained in Step 6 with GZH-4 to form a 1mm anti-oxidation coating, select two sheets and stack them. Then, wrap them with a steel clasp consisting of upper and lower cover steel plates and side sealing steel plates to obtain a covered stacked ladle. The steel clasp has vent holes at both ends. The ratio of the total thickness of the two third intermediate slabs to the thickness of the upper and lower cover steel plates is 0.6. Step 8: The cladding and rolled ladle obtained in Step 7 is subjected to a fourth rolling process at 895℃~925℃. After uncoating, it is annealed at 765℃~795℃. After surface treatment, a Ti80 titanium alloy sheet is obtained. The fourth rolling process is completed in 7 passes, with the following deformation rates for each pass: 10%, 17%, 21%, 17%, 20%, 20%, and 7%, respectively. The total deformation rate is 80%, the rolling speed is 3m / s, and the final rolling temperature is not lower than 700℃. The rolling direction of the fourth rolling process is the same as that of the third rolling process in Step 5. The thickness of the Ti80 titanium alloy sheet is 2mm, and the width is 1500mm.

[0026] Metallographic analysis was performed on the Ti80 titanium alloy thin plate prepared in this embodiment, such as... Figure 1 As shown, the microstructure of the Ti80 titanium alloy sheet is uniform and fine equiaxed α grains. Testing revealed that the room temperature tensile strength of the Ti80 titanium alloy sheet prepared in this embodiment is 1030 MPa to 1040 MPa, the yield strength is 925 MPa to 935 MPa, and the elongation after fracture is 13% to 14%. In summary, the microstructure of the Ti80 titanium alloy prepared in this embodiment meets the microstructure requirements of Ti80 single-phase titanium alloy, and it has excellent mechanical properties.

[0027] Example 2 This embodiment includes the following steps: Step 1: The Ti80 titanium alloy slab is rolled in the first pass at 945℃~975℃, and then reheated in the furnace online to obtain the first rolled slab. The Ti80 titanium alloy slab has a thickness of 160mm, a width of 1900mm, and a length of 1300mm. The first pass is a unidirectional rolling process with 11 passes. The deformation rates for each pass are 5%, 8%, 10%, 11%, 13%, 13%, 11%, 10.5%, 7.5%, 5.5%, and 4%, respectively. After reheating in the furnace for 60 minutes in the sixth pass, the total deformation rate of the first pass is 65%, the rolling speed is 4m / s, and the final rolling temperature is not lower than 750℃. Before the first pass, a 2mm thick anti-oxidation coating of GZH-4 is applied to the surface of the Ti80 titanium alloy slab. The first rolled slab has a thickness of 56mm and a width of 1900mm. Step 2: Cut the first rolled slab obtained in Step 1 to obtain multiple first intermediate slabs; the thickness of the first intermediate slab is 56mm, the width is 1900mm, and the length is 1150mm. Step 3: The first intermediate slab obtained in Step 2 is subjected to a second rolling process at 925℃~955℃, and then reheated in the furnace online to obtain the second rolled slab. The second rolling process consists of 8 passes, with the following deformation rates for each pass: 12%, 13%, 14%, 17%, 13%, 14%, 15%, and 15%, respectively, for a total deformation rate of 70%. The rolling speed is 4 m / s, and the final rolling temperature is not lower than 400℃. The rolling direction of the second rolling process is the same as that of the first rolling process in Step 1. Before the second rolling process, a 2 mm thick anti-oxidation coating of GZH-4 paint is applied to the surface of the first intermediate slab. The second rolled slab has a thickness of 17 mm and a width of 1900 mm. Step 4: Cut the second rolled slab obtained in Step 3 to obtain multiple second intermediate slabs; the thickness of the second intermediate slab is 17mm, the width is 1900mm, and the length is 1800mm. Step 5: The second intermediate slab obtained in Step 4 is subjected to a third rolling process at a temperature of 905℃~935℃, and then reheated in the furnace online to obtain the third rolled slab. The third rolling process consists of 3 passes, with the deformation rates of each pass being 14%, 13%, and 9%, respectively, for a total deformation rate of 35%. The rolling speed is 4 m / s, and the final rolling temperature is not lower than 400℃. The rolling direction of the third rolling process is perpendicular to the rolling direction of the second rolling process in Step 3. Before the third rolling process, a 1.5 mm thick anti-oxidation coating of GZH-4 paint is applied to the surface of the second intermediate slab. The thickness of the third rolled slab is 11 mm, and the width is 1800 mm. Step 6: Cut the third rolled slab obtained in Step 5 to obtain multiple third intermediate slabs; the thickness of the third intermediate slab is 11mm, the width is 1800mm, and the length is 900mm. Step 7: Apply a 1.5mm thick anti-oxidation coating of GZH-4 paint to the surface of the third intermediate slab obtained in Step 6, then select two slabs and stack them together. Then, wrap them with a steel clasp consisting of upper and lower cover steel plates and side sealing steel plates to obtain a covered stacked ladle. The steel clasp has vent holes at both ends, and the ratio of the total thickness of the two third intermediate slabs to the thickness of the upper and lower cover steel plates is 0.8. Step 8: The cladding and rolled ladle obtained in Step 7 is subjected to a fourth rolling process at 885℃~915℃. After uncoating, it is annealed at 785℃~815℃. After surface treatment, a Ti80 titanium alloy sheet is obtained. The fourth rolling process consists of 8 passes, with the following deformation rates for each pass: 7%, 9%, 10%, 12%, 21%, 12%, 11%, and 12%, respectively. The total deformation rate is 60%, the rolling speed is 4 m / s, and the final rolling temperature is not lower than 700℃. The rolling direction of the fourth rolling process is the same as that of the third rolling process in Step 5. The thickness of the Ti80 titanium alloy sheet is 4 mm, and the width is 1800 mm.

[0028] Metallographic analysis was performed on the Ti80 titanium alloy thin plate prepared in this embodiment, such as... Figure 2 As shown, the microstructure of the Ti80 titanium alloy sheet is uniform and fine equiaxed α grains. Testing revealed that the room temperature tensile strength of the Ti80 titanium alloy sheet prepared in this embodiment is 980 MPa to 990 MPa, the yield strength is 890 MPa to 900 MPa, and the elongation after fracture is 14% to 16%. In summary, the microstructure of the Ti80 titanium alloy prepared in this embodiment meets the microstructure requirements of Ti80 single-phase titanium alloy, and it has excellent mechanical properties.

[0029] Example 3 This embodiment includes the following steps: Step 1: The Ti80 titanium alloy slab is rolled in the first pass at 955℃~985℃, and then reheated in the furnace online to obtain the first rolled slab. The Ti80 titanium alloy slab has a thickness of 180mm, a width of 2100mm, and a length of 1200mm. The first pass is a unidirectional rolling process with 12 passes. The deformation rates of each pass are 11%, 12%, 13%, 13%, 12%, 12%, 11%, 11%, 10%, 10%, 10%, and 4%, respectively. After reheating in the furnace for 60 minutes in the sixth pass, the total deformation rate of the first pass is 75%, the rolling speed is 4m / s, and the final rolling temperature is not lower than 750℃. Before the first pass, a 2mm thick anti-oxidation coating of GZH-4 is applied to the surface of the Ti80 titanium alloy slab. The first rolled slab has a thickness of 45mm and a width of 2100mm. Step 2: Cut the first rolled slab obtained in Step 2 to obtain multiple first intermediate slabs; the thickness of the first intermediate slab is 45mm, the width is 2100mm, and the length is 1500mm. Step 3: The first intermediate slab obtained in Step 2 is subjected to a second rolling process at 935℃~965℃, and then reheated in the furnace online to obtain the second rolled slab. The second rolling process consists of 6 passes, with the deformation rates of each pass being 12%, 14%, 17%, 14%, 14%, and 12%, respectively, for a total deformation rate of 60%. The rolling speed is 4m / s, and the final rolling temperature is not lower than 400℃. The rolling direction of the second rolling process is the same as that of the first rolling process in Step 1. Before the second rolling process, a 2mm thick anti-oxidation coating of GZH-4 paint is applied to the surface of the first intermediate slab. The thickness of the second rolled slab is 19mm, and the width is 2100mm. Step 4: Cut the second rolled slab obtained in Step 3 to obtain multiple second intermediate slabs; the thickness of the second intermediate slab is 19mm, the width is 2100mm, and the length is 1650mm. Step 5: The second intermediate slab obtained in Step 4 is subjected to a third rolling process at 915℃~945℃, and then reheated in the furnace online to obtain the third rolled slab. The third rolling process consists of 4 passes, with the deformation rates of each pass being 10%, 14%, 10%, and 9%, respectively, for a total deformation rate of 37%. The rolling speed is 4 m / s, and the final rolling temperature is not lower than 400℃. The rolling direction of the third rolling process is perpendicular to the rolling direction of the second rolling process in Step 3. Before the third rolling process, a 2 mm thick anti-oxidation coating of GZH-4 paint is applied to the surface of the second intermediate slab. The thickness of the third rolled slab is 12 mm, and the width is 1650 mm. Step 6: Cut the third rolled slab obtained in Step 5 to obtain multiple third intermediate slabs; the thickness of the third intermediate slab is 12mm, the width is 1650mm, and the length is 1000mm. Step 7: After coating the surface of the third intermediate slab obtained in Step 6 with a 2mm thick anti-oxidation coating using GZH-4 paint, select one sheet and stack it. Then, wrap it with a steel clasp consisting of upper and lower cover steel plates and side sealing steel plates to obtain a covered stacked ladle. The steel clasp has vent holes at both ends, and the thickness ratio of one third intermediate slab to the thickness of the upper and lower cover steel plates is 1. Step 8: The cladding and rolled ladle obtained in Step 7 is subjected to a fourth rolling process at 875℃~905℃. After uncoiling, it is annealed at 805℃~835℃, and then surface treated to obtain a Ti80 titanium alloy sheet. The fourth rolling process consists of 9 passes, with the following deformation rates for each pass: 7%, 14%, 21%, 18%, 16%, 16%, 14%, 12%, and 10%, respectively. The total deformation rate is 75%, the rolling speed is 4 m / s, and the final rolling temperature is not lower than 700℃. The rolling direction of the fourth rolling process is the same as that of the third rolling process in Step 5. The thickness of the Ti80 titanium alloy sheet is 3 mm, and the width is 1650 mm.

[0030] Metallographic analysis was performed on the Ti80 titanium alloy thin plate prepared in this embodiment, such as... Figure 3 As shown, the metallographic structure of the Ti80 titanium alloy sheet is uniform and fine equiaxed α grains. Testing revealed that the room temperature tensile strength of the Ti80 titanium alloy sheet prepared in this embodiment is 1010 MPa~1020 MPa, the yield strength is 910 MPa~930 MPa, and the elongation after fracture is 14%~16%. In summary, the microstructure of the Ti80 titanium alloy prepared in this embodiment meets the microstructure requirements of Ti80 single-phase titanium alloy, and it has excellent mechanical properties.

[0031] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A rolling method for Ti80 titanium alloy thin plates, characterized in that, Includes the following steps: Step 1: A Ti80 titanium alloy slab with a thickness of 150mm~180mm, a width of 1800mm~2100mm, and a length of 1200mm~1400mm is rolled in a first pass at 935℃~985℃ and then reheated in an online furnace to obtain a first rolled slab with a thickness of 45mm~60mm and a width of 1800mm~2100mm. The first pass rolling is unidirectional rolling, with a pass deformation rate of 4%~13% and a rolling speed of 3m / s~4m / s. Step 2: Cut the first rolled slab obtained in Step 1 to obtain multiple first intermediate slabs; Step 3: The first intermediate slab obtained in Step 2 is subjected to a second rolling process at 915℃~965℃, and then returned to the furnace for reheating online to obtain a second rolled slab with a thickness of 17mm~20mm and a width of 1800mm~2100mm. The deformation rate of the second rolling pass is 12%~17%, the rolling speed is 3m / s~4m / s, and the rolling direction is the same as that of the first rolling process in Step 1. Before the second rolling, an anti-oxidation coating is applied to the surface of the first intermediate slab. The final rolling temperature of the second rolling is not lower than 400℃, and the total deformation rate of the second rolling is 60%~70%. The thickness of the first intermediate slab is 45mm~60mm, the width is 1800mm~2100mm, and the length is 1050mm~1500mm. Step 4: Cut the second rolled slab obtained in Step 3 to obtain multiple second intermediate slabs; Step 5: The second intermediate slab obtained in Step 4 is rolled for a third time at 895℃~945℃, and then returned to the furnace for reheating online to obtain a third rolled slab with a thickness of 10mm~12mm and a width of 1500mm~1800mm. The deformation rate of the third rolling pass is 9%~14%, the rolling speed is 3m / s~4m / s, and the rolling direction is perpendicular to the rolling direction of the second rolling in Step 3. Before the third rolling, an anti-oxidation coating is applied to the surface of the second intermediate slab. The final rolling temperature of the third rolling is not lower than 400℃, and the total deformation rate of the third rolling is 35%~50%. The thickness of the second intermediate slab is 17mm~20mm, the width is 1800mm~2100mm, and the length is 1500mm~1800mm. Step 6: Cut the third rolled slab obtained in step 5 to obtain multiple third intermediate slabs; the thickness of the third intermediate slab is 10mm~12mm, the width is 1500mm~1800mm, and the length is 900mm~1100mm. Step 7: After coating the surface of the third intermediate slab obtained in Step 6 with an anti-oxidation coating, select several sheets and stack them, then wrap them with a steel clasp to obtain a wrapped and stacked ladle. Step 8: The cladding and rolled ladle obtained in Step 7 is subjected to a fourth rolling process at 875℃~925℃. After uncoating, it is annealed at 765℃~835℃ to obtain a Ti80 titanium alloy sheet with a thickness of 2mm~4mm and a width of 1500mm~1800mm. The deformation rate of the fourth rolling pass is 7%~21%, the rolling speed is 3m / s~4m / s, and the rolling direction is the same as that of the third rolling process in Step 5.

2. The rolling method for a Ti80 titanium alloy thin plate according to claim 1, characterized in that, In step one, before the first rolling, an anti-oxidation coating is applied to the surface of the Ti80 titanium alloy slab. The final rolling temperature of the first rolling is not lower than 750°C, and the total deformation rate of the first rolling is 60%~75%.

3. The rolling method for a Ti80 titanium alloy thin plate according to claim 1, characterized in that, The steel ladle sleeve mentioned in step seven includes upper and lower cover steel plates and side sealing steel plates. The steel ladle sleeve has vent holes at both ends. The ratio of the total thickness of the third intermediate slab in the cladding ladle to the thickness of the upper and lower cover steel plates is 0.6~1.

4. The rolling method for a Ti80 titanium alloy thin plate according to claim 1, characterized in that, The final rolling temperature of the fourth rolling in step eight shall not be lower than 700°C, and the total deformation rate of the fourth rolling shall be 60%~80%.

5. A rolling method for a Ti80 titanium alloy sheet according to any one of claims 1 or 2, characterized in that, The thickness of the anti-oxidation coating is 1mm to 2mm.

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