Ti80 ultra-wide titanium alloy thick plate and method for manufacturing the same

Abstract

The application relates to a Ti80 super-wide-width titanium alloy thick plate and a preparation method thereof, and belongs to the technical field of titanium alloy processing, and solves the problem of low impact toughness of Ti80 titanium alloy with large width and thickness prepared by an existing method. A Ti80 super-wide-width titanium alloy thick plate comprises the following chemical components in percentage by weight: Al 5.6-6.4%, Nb 2.8-3.2%, Mo 0.9-1.5%, Zr 1.9-2.1%, Si not more than 0.01%, O not more than 0.09%, C not more than 0.01%, H not more than 0.01%, N not more than 0.01%, Fe not more than 0.04%, and the balance of Ti and inevitable impurities. The Ti80 titanium alloy thick plate product with a width of more than 3000 mm is successfully prepared, and has good mechanical properties and impact toughness.

Description

Technical Field

[0001] This invention relates to the field of titanium processing technology, and in particular to a Ti80 ultra-wide titanium alloy thick plate and its preparation method. Background Technology

[0002] Titanium is an important structural metal developed in the 1950s. Titanium alloys are widely used in various fields due to their high strength, good corrosion resistance, and high heat resistance. Ti80 titanium alloy, with a nominal composition of Ti-6Al-3Nb-2Zr-1Mo, is a near-α type titanium alloy with a high aluminum content and containing β-type stabilizing elements Nb and Mo, as well as the neutral element Zr. It features low density, high specific strength, high temperature resistance, and non-magnetic properties, and is widely used in aerospace, chemical, and shipbuilding fields, generally in load-bearing components, bolts, shafts, and pressure-resistant and corrosion-resistant shells.

[0003] With the increasing application of Ti80 titanium alloys in shipbuilding and other fields, the industry is placing increasingly higher demands on the width of titanium alloys. Existing methods for producing wide and thick Ti80 titanium alloys result in lower impact toughness, which cannot fully meet application requirements. Furthermore, there are currently no Ti80 titanium alloy thick plates with a width exceeding 3000 mm in the industry. Therefore, developing an ultra-wide Ti80 titanium alloy thick plate is of great significance for the development of the industry and the application of titanium alloys. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a Ti80 ultra-wide titanium alloy thick plate and its preparation method, at least to solve one of the following problems: 1. Existing methods for preparing Ti80 titanium alloys with large width and thickness result in low impact toughness; 2. There are currently no Ti80 titanium alloy thick plate products with a width exceeding 3000 mm in the industry.

[0005] The objective of this invention is mainly achieved through the following technical solutions:

[0006] This invention provides a Ti80 ultra-wide titanium alloy thick plate, the chemical composition of which, by weight, comprises: Al 5.6%–6.4%, Nb 2.8%–3.2%, Mo 0.9%–1.5%, Zr 1.9%–2.1%, Si not greater than 0.01%, O not greater than 0.09%, C not greater than 0.01%, H not greater than 0.01%, N not greater than 0.01%, Fe not greater than 0.04%, with the balance being Ti and unavoidable impurities.

[0007] Furthermore, the chemical composition of the Ti80 ultra-wide titanium alloy thick plate, by weight, comprises: Al 5.6%–6.2%, Nb 2.9%–3.1%, Mo 0.9%–1.0%, Zr 2.0%–2.1%, Si not greater than 0.01%, O not greater than 0.06%, C not greater than 0.01%, H not greater than 0.01%, N not greater than 0.01%, Fe not greater than 0.04%, with the balance being Ti and unavoidable impurities.

[0008] Furthermore, the microstructure of the Ti80 ultra-wide titanium alloy thick plate includes a primary α phase and a lamellar transformation β phase, wherein the volume fraction of the lamellar transformation β phase is >35%.

[0009] This invention also provides a method for preparing Ti80 ultra-wide titanium alloy thick plates, comprising the following steps:

[0010] S1: Ingot smelting, zero-grade small-particle sponge titanium, sponge zirconium, aluminum granules, Al-Mo master alloy, Al-Nb master alloy are mixed and pressed into electrodes, and then the obtained electrodes are smelted in a vacuum consumable arc furnace three times to obtain Ti80 ingots.

[0011] S2: Intermediate grinding: Grinding the Ti80 ingot;

[0012] S3: Slab forging: The Ti80 ingots that have been ground in step S2 are subjected to slab forging and semi-finished and finished forging to obtain Ti80 alloy square billets.

[0013] S4: Slab pressing: The Ti80 alloy square billet is placed in a heating furnace and heated and held at 950-1000℃ for 4-6 hours. Then it is transferred to a rolling mill for unidirectional rolling. The rolling deformation is 60%-90% to obtain a rolled plate.

[0014] S5: Annealing treatment: The rolled plate is annealed, then hot-shaped and cooled after being taken out of the furnace to obtain the annealed plate.

[0015] S6: Fine finishing: The sheet metal is finely finished to obtain Ti80 ultra-wide titanium alloy thick plate.

[0016] Furthermore, in step S3, the forging process is divided into three firing cycles, with a total deformation of ≥80%.

[0017] Furthermore, in step S3, the forging temperature of the semi-finished product and the finished product is 950℃~1000℃, and the forging is carried out in no less than three forging cycles.

[0018] Furthermore, in step S3, the total deformation of the semi-finished product and the finished product forging is ≥70%, and the final forging temperature is ≥960℃.

[0019] Furthermore, in step S4, the unidirectional rolling passes are ≥15 passes.

[0020] Furthermore, in step S4, the rolling speed of the unidirectional rolling is ≤8m / s.

[0021] Furthermore, in step S5, the annealing temperature is 960℃~990℃, and the annealing holding time is 1.5~3h.

[0022] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0023] 1. This invention, through the design of a reasonable alloy composition, preparation method, and strict control of process parameters, achieves the preparation of Ti80 ultra-wide titanium alloy thick plates with a thickness of 40-80 mm and a width of 3000-4000 mm, while possessing excellent comprehensive mechanical properties, with a tensile strength Rm ≥ 920 MPa and a yield strength Rp 0.2 With a strength of ≥800MPa, elongation A≥14%, reduction of area Z≥25%, and impact energy Kv2≥50J, this product possesses excellent mechanical properties and impact toughness, meeting the application requirements of various fields such as shipbuilding and aerospace. It has promising application prospects, filling the gap in the domestic market for ultra-wide Ti80 thick plates, and can be widely used in shipbuilding, aerospace, and other fields.

[0024] 2. The present invention uses a wide-width rolling mill for hot rolling combined with subsequent annealing, which solves the problem of uneven microstructure in ultra-wide titanium alloy thick plate materials, increases the yield, reduces the time and material costs of subsequent uniform microstructure, and helps to reduce costs and improve production efficiency.

[0025] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0026] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0027] Figure 1 This is a microstructure image of the Ti80 ultra-wide titanium alloy thick plate in Example 1 of the present invention;

[0028] Figure 2 This is a microstructure image of the Ti80 ultra-wide titanium alloy thick plate in Example 2 of the present invention;

[0029] Figure 3 This is a microstructure diagram of the Ti80 ultra-wide titanium alloy thick plate in Example 3 of the present invention. Detailed Implementation

[0030] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0031] This invention provides a Ti80 ultra-wide titanium alloy thick plate, the chemical composition of which, by weight, comprises: Al 5.6%–6.4%, Nb 2.8%–3.2%, Mo 0.9%–1.5%, Zr 1.9%–2.1%, Si not greater than 0.01%, O not greater than 0.09%, C not greater than 0.01%, H not greater than 0.01%, N not greater than 0.01%, Fe not greater than 0.04%, with the balance being Ti and unavoidable impurities.

[0032] The reasons for limiting the composition of the Ti80 ultra-wide titanium alloy thick plate and its preparation method in this invention will be explained. Hereinafter, only the percentage of mass in the composition is expressed as %.

[0033] Al: Belongs to the α-phase stabilizing element. Al is the most important strengthening element in titanium alloys. With a few exceptions, Al is present in almost all titanium alloys. Al has a very significant solid solution strengthening effect. Its solid solubility in α-Ti is greater than that in β-Ti, and it increases the temperature of the interconversion between the α and β phases, expanding the α phase region. When the Al content exceeds 6-8%, an ordered Ti3Al brittle phase will precipitate in the alloy, reducing the thermal stability of the alloy. Taking all factors into consideration, the Al content is limited to 5.6% to 6.4% in this invention.

[0034] Mo: Belongs to the β isocrystalline element and has a β phase stabilizing effect; Mo is infinitely soluble in β-Ti and also has a certain solid solubility in α-Ti; It has a significant solid solution strengthening effect and can improve the strength of the alloy, but excessive addition will lead to loss of plasticity and toughness; This invention limits the content of Mo to 0.9% to 1.5%.

[0035] Nb: Belongs to the β isomorphous element and has obvious solid solution strengthening effect. Nb can replace part of Mo and play a role in multi-element strengthening. The addition of Nb can also improve the high-temperature oxidation resistance and corrosion resistance of the alloy. The present invention limits the Nb content to 2.8% to 3.2%.

[0036] Zr: A neutral element, Zr has high solubility in both α-Ti and β-Ti. It is usually added together with other elements, which can strengthen titanium with little adverse effect on plasticity. It is a commonly used solid solution strengthening element. This invention limits the Zr content to 1.9% to 2.1%.

[0037] Preferably, a Ti80 ultra-wide titanium alloy thick plate, wherein the chemical composition of the Ti80 ultra-wide titanium alloy thick plate, by weight, comprises: Al 5.6%–6.2%, Nb 2.9%–3.1%, Mo 0.9%–1.0%, Zr 2.0%–2.1%, Si not greater than 0.01%, O not greater than 0.06%, C not greater than 0.01%, H not greater than 0.01%, N not greater than 0.01%, Fe not greater than 0.04%, with the balance being Ti and unavoidable impurities.

[0038] This invention also provides a method for preparing the above-mentioned Ti80 ultra-wide titanium alloy thick plate, which includes the following steps:

[0039] S1: Ingot smelting, zero-grade small-particle sponge titanium, sponge zirconium, aluminum granules, Al-Mo master alloy, Al-Nb master alloy are mixed and pressed into electrodes, and then the obtained electrodes are smelted in a vacuum consumable arc furnace three times to obtain Ti80 ingots.

[0040] S2: Intermediate grinding: Grinding the Ti80 ingot;

[0041] S3: Slab forging: The Ti80 ingots that have been ground in step S2 are subjected to slab forging and semi-finished and finished forging to obtain Ti80 alloy square billets.

[0042] S4: Slab pressing: The Ti80 alloy square billet is placed in a heating furnace and heated and held at 950-1000℃ for 4-6 hours. Then it is transferred to a rolling mill for unidirectional rolling. The rolling deformation is 60%-90% to obtain a rolled plate.

[0043] S5: Annealing treatment: The rolled plate is annealed, then hot-shaped and cooled after being taken out of the furnace to obtain the annealed plate.

[0044] S6: Fine finishing: The sheet metal is finely finished to obtain Ti80 ultra-wide titanium alloy thick plate.

[0045] Specifically, in step S3, the Ti80 ingot, after being ground in step S2, undergoes initial forging and semi-finished / finished forging to obtain a Ti80 alloy square billet. The specific process is as follows: the Ti80 ingot, after being ground in step S2, is placed in a heating furnace and heated at 1100–1200℃ for 4–6 hours. Then, it is transferred to a press for initial forging, which is performed in three passes with a total deformation of not less than 80%. The final forging temperature is >1000℃. Immediately afterwards, semi-finished / finished forging is carried out at an initial forging temperature of 950℃–1000℃. This process is completed in at least three passes with a total deformation of not less than 70%, and a final forging temperature ≥960℃. After air cooling, the billet is shaped and milled to obtain a square billet.

[0046] Specifically, in step S4, the Ti80 alloy billet is placed in a heating furnace and heated and held at 950-1000℃ for 4-6 hours. Then, it is transferred to a rolling mill for unidirectional rolling. The rolling deformation is 60%-90% to obtain a rolled plate. The rolling process is no less than 15 passes and the rolling speed is ≤8m / s.

[0047] Specifically, in step S5, the rolled plate is annealed, then hot-shaped after being taken out of the furnace, and cooled to obtain the annealed plate; wherein, the annealing temperature is 960℃~990℃, and the holding time is 1.5~3h.

[0048] It should be noted that in the titanium alloy ingot forging and semi-finished and finished product forging processes, this invention designs a three-stage forging process. The forging temperature is higher than the phase transformation point of the α and β phases, which ensures that the coarse grains of the ingot are fully broken up. Subsequently, during repeated forging in the α+β two-phase region, the heating temperature is slightly lower than the phase transformation point, which can improve the toughness and high-temperature performance of the titanium alloy and obtain a fine-grained and homogenized dual-state microstructure (i.e., simultaneously possessing the primary α phase and the lamellar transformation β phase). The dual-state microstructure enables the titanium alloy to simultaneously possess good impact performance and ductility, which helps to improve the cracking susceptibility of the plate. After rolling, annealing is performed at a temperature set about 10-25°C lower than the phase transformation point, held for 1.5-3 hours and air-cooled to obtain a high content of lamellar transformation β phase. The high content of lamellar transformation β phase ensures that the obtained Ti80 titanium alloy thick plate has both high impact performance and mechanical properties.

[0049] The ultra-wide titanium alloy thick plate obtained by the preparation method of the present invention has a microstructure of "primary α phase + lamellar transformation β phase", wherein the volume fraction of lamellar transformation β phase is >35%.

[0050] The Ti80 ultra-wide titanium alloy thick plate prepared by this invention has a thickness of 40-80 mm and a width of 3000-4000 mm, and also possesses good comprehensive mechanical properties, with a tensile strength R... m ≥860MPa, yield strength Rp0.2 With an impact strength of ≥760MPa, elongation A≥10%, reduction of area Z≥20%, and impact energy Kv2≥50J, it can meet the application requirements of various fields such as shipbuilding and aerospace, and has good application scenarios.

[0051] Example 1

[0052] The Ti80 ultra-wide titanium alloy thick plate of this embodiment has the following chemical composition by weight percentage: Al 5.6%, Nb 2.9%, Mo 0.9%, Zr 2.1%, O 0.046%, Fe 0.034%, Si not more than 0.01%, C not more than 0.01%, H not more than 0.01%, N not more than 0.01%, with the balance being Ti and unavoidable impurities.

[0053] The preparation method of this embodiment includes the following steps:

[0054] S1: Ingot smelting, zero-grade small-particle sponge titanium, sponge zirconium, aluminum granules, Al-Mo master alloy, Al-Nb master alloy are mixed and pressed into electrodes, and then the obtained electrodes are smelted in a vacuum consumable arc furnace three times to obtain Ti80 ingots.

[0055] S2: Intermediate grinding: Grinding the Ti80 ingot;

[0056] S3: Slab forging: The Ti80 ingots that have been ground in step S2 are subjected to slab forging and semi-finished and finished forging to obtain Ti80 alloy square billets.

[0057] The specific process is as follows: the Ti80 ingot after grinding in step S2 is placed in a heating furnace, heated and held at 1150℃ for 4 hours, and then transferred to a press for billet forging. The billet forging is divided into three heats, with a total deformation of 85% and a final forging temperature of 1050℃.

[0058] Semi-finished and finished products are forged. The initial forging temperature is 981℃. The forging process of semi-finished and finished products is completed in three forging cycles. The total deformation is 81%. The final forging temperature is 970℃.

[0059] After air cooling, the billet is shaped and milled to obtain a square billet with dimensions of 280mm×1300mm×2400mm.

[0060] S4: Slab pressing: The Ti80 alloy square billet is placed in a heating furnace and heated and held at 960℃ for 4 hours. Then it is transferred to a 3300mm rolling mill for unidirectional rolling. The rolling is completed in 24 passes at a rolling speed of 8m / s. The total deformation is 84%, and a rolled plate is obtained.

[0061] S5: Annealing treatment: The rolled plate is annealed, then hot-shaped and cooled after being taken out of the furnace to obtain the annealed plate; the annealing temperature is 980℃ and the holding time is 2h.

[0062] S6: Fine finishing: The sheet metal is finely finished to obtain Ti80 ultra-wide titanium alloy thick plate.

[0063] The Ti80 ultra-wide titanium alloy thick plate prepared in this embodiment has a size of 45mm×3000mm×6000mm, that is, a thickness of 45mm and a width of 3000mm.

[0064] Example 2

[0065] The Ti80 ultra-wide titanium alloy thick plate of this embodiment has the following chemical composition by weight percentage: Al 5.8%, Nb 3.1%, Mo 1.0%, Zr 2.0%, O 0.036%, Fe 0.038%, Si not more than 0.01%, C not more than 0.01%, H not more than 0.01%, N not more than 0.01%, with the balance being Ti and unavoidable impurities.

[0066] The preparation method of this embodiment includes the following steps:

[0067] S1: Ingot smelting, zero-grade small-particle sponge titanium, sponge zirconium, aluminum granules, Al-Mo master alloy, Al-Nb master alloy are mixed and pressed into electrodes, and then the obtained electrodes are subjected to three vacuum self-consuming arc melting to obtain Ti80 ingots.

[0068] S2: Intermediate grinding: Grinding the Ti80 ingot;

[0069] S3: Slab forging: The Ti80 ingots that have been ground in step S2 are subjected to slab forging and semi-finished and finished forging to obtain Ti80 alloy square billets.

[0070] The specific process is as follows: the Ti80 ingot after grinding in step S2 is placed in a heating furnace, heated and held at 1130℃ for 4 hours, and then transferred to a press for billet forging. The billet forging is completed in three heats, with a total deformation of 87% and a final forging temperature of 1060℃.

[0071] Semi-finished and finished products are forged. The initial forging temperature is 985℃. The forging process of semi-finished and finished products is completed in three forging cycles. The total deformation is 79%. The final forging temperature is 970℃.

[0072] After air cooling, the billet is shaped and milled to obtain a square billet with dimensions of 290mm×1300mm×2400mm.

[0073] S4: Slab pressing: The Ti80 alloy square billet is placed in a heating furnace and heated and held at 970℃ for 4 hours. Then it is transferred to a 3300mm rolling mill for unidirectional rolling. The rolling is completed in 26 passes at a rolling speed of 6m / s. The total deformation is 86%, and a rolled plate is obtained.

[0074] S5: Annealing treatment: The rolled plate is annealed, then hot-shaped and cooled after being taken out of the furnace to obtain the annealed plate; the annealing temperature is 985℃ and the holding time is 2h.

[0075] S6: Fine finishing: The sheet metal is finely finished to obtain Ti80 ultra-wide titanium alloy thick plate.

[0076] The Ti80 ultra-wide titanium alloy thick plate prepared in this embodiment has a size of 45mm×3200mm×5800mm, that is, a thickness of 45mm and a width of 3200mm.

[0077] Example 3

[0078] The Ti80 ultra-wide titanium alloy thick plate of this embodiment has the following chemical composition by weight percentage: Al 6.2%, Nb 2.9%, Mo 0.95%, Zr 2.1%, O 0.051%, Fe 0.029%, Si not more than 0.01%, C not more than 0.01%, H not more than 0.01%, N not more than 0.01%, with the balance being Ti and unavoidable impurities.

[0079] The preparation method of this embodiment includes the following steps:

[0080] S1: Ingot smelting, zero-grade small-particle sponge titanium, sponge zirconium, aluminum granules, Al-Mo master alloy, Al-Nb master alloy are mixed and pressed into electrodes, and then the obtained electrodes are subjected to three vacuum self-consuming arc melting to obtain Ti80 ingots.

[0081] S2: Intermediate grinding: Grinding the Ti80 ingot;

[0082] S3: Slab forging: The Ti80 ingots that have been ground in step S2 are subjected to slab forging and semi-finished and finished forging to obtain Ti80 alloy square billets.

[0083] The specific process is as follows: the Ti80 ingot after grinding in step S2 is placed in a heating furnace, heated and held at 1200℃ for 6 hours, and then transferred to a press for billet forging. The billet forging is completed in three heats, with a total deformation of 81% and a final forging temperature of 1040℃.

[0084] The semi-finished and finished products are forged. The initial forging temperature is 990℃. The forging process of semi-finished and finished products is completed in three forging cycles. The total deformation is 85%. The final forging temperature is 970℃.

[0085] After air cooling, the billet is shaped and milled to obtain a square billet with dimensions of 400mm×1300mm×3000mm.

[0086] S4: Slab pressing: The Ti80 alloy square billet is placed in a heating furnace and heated at 1000℃ for 6 hours. Then it is transferred to a 4200mm rolling mill for unidirectional rolling. The rolling is completed in 30 passes at a rolling speed of 4m / s. The total deformation is 82%, and a rolled plate is obtained.

[0087] S5: Annealing treatment: The rolled plate is annealed, then hot-shaped after exiting the furnace, and cooled to obtain the annealed plate; the annealing temperature is 990℃ and the holding time is 2.5h.

[0088] S6: Fine finishing: The sheet metal is finely finished to obtain Ti80 ultra-wide titanium alloy thick plate.

[0089] The Ti80 ultra-wide titanium alloy thick plate prepared in this embodiment has a size of 75mm×4000mm×6000mm, that is, a thickness of 75mm and a width of 4000mm.

[0090] Comparative Example 1

[0091] The Ti80 ultra-wide titanium alloy thick plate of this comparative example has the following chemical composition by weight percentage: Al 7.1%, Nb 2.8%, Mo 0.8%, Zr 2.5%, O 0.054%, Fe 0.038%, Si not more than 0.01%, C not more than 0.01%, H not more than 0.01%, N not more than 0.01%, with the balance being Ti and unavoidable impurities.

[0092] The preparation method and process parameters of the Ti80 ultra-wide titanium alloy thick plate in this comparative example are the same as those in Example 1.

[0093] Comparative Example 2

[0094] The Ti80 ultra-wide titanium alloy thick plate of this comparative example has the same chemical composition and content as that in Example 3, that is, the chemical composition by weight percentage includes: Al 6.2%, Nb 2.9%, Mo 0.85%, Zr 2.3%, O 0.051%, C not greater than 0.01%, H not greater than 0.01%, N not greater than 0.01%, and the balance is Ti and unavoidable impurities.

[0095] The preparation method of this comparative example includes the following steps:

[0096] S1: Directly select the ingot from Example 3 for subsequent processes;

[0097] S2: Intermediate grinding: Grinding the Ti80 ingot;

[0098] S3: Slab forging: The Ti80 ingots that have been ground in step S2 are subjected to slab forging and semi-finished and finished forging to obtain Ti80 alloy square billets.

[0099] The specific process is as follows: the Ti80 ingot after grinding in step S2 is placed in a heating furnace, heated and held at 1150℃ for 4 hours, and then transferred to a press for billet forging. The billet forging is completed in two heats, with a total deformation of 80% and a final forging temperature of 1040℃.

[0100] Semi-finished and finished products are forged. The initial forging temperature is 983℃. The forging process of semi-finished and finished products is completed in two forging passes. The total deformation is 75%. The final forging temperature is 970℃.

[0101] After air cooling, the billet is shaped and milled to obtain a square billet with dimensions of 310mm×1500mm×2600mm.

[0102] S4: Slab pressing: The Ti80 alloy square billet is placed in a heating furnace and heated at 960℃ for 4 hours. Then it is transferred to a 3300mm rolling mill for unidirectional rolling. The rolling is completed in 10 passes at a rolling speed of 12m / s. The total deformation is 84%, and the rolled plate is obtained.

[0103] S5: Annealing treatment: The rolled plate is annealed, then hot-shaped and cooled after being taken out of the furnace to obtain the annealed plate; the annealing temperature is 980℃ and the holding time is 2h.

[0104] S6: Fine finishing: Cracks were found in the slab. The slab was then finely finished. After cutting the cracks, a thick Ti80 titanium alloy plate was obtained.

[0105] The Ti80 titanium alloy thick plate obtained in this embodiment has a size of 30mm×2500mm×6000mm, that is, a thickness of 30mm and a width of 2500mm.

[0106] Comparative Example 3

[0107] The Ti80 ultra-wide titanium alloy thick plate of this comparative example has the following chemical composition by weight percentage: Al 6.02%, Nb 2.97%, Mo 1.02%, Zr 2.1%, O 0.1%, Fe 0.04%, Si not more than 0.01%, C not more than 0.01%, H not more than 0.01%, N not more than 0.01%, with the balance being Ti and unavoidable impurities.

[0108] The preparation method of this comparative example includes the following steps:

[0109] S1: Ingot smelting, zero-grade small-particle sponge titanium, sponge zirconium, aluminum granules, Al-Mo master alloy, Al-Nb master alloy are mixed and pressed into electrodes, and then the obtained electrodes are subjected to three vacuum self-consuming arc melting to obtain Ti80 ingots.

[0110] S2: Intermediate grinding: Grinding the Ti80 ingot;

[0111] S3: Slab forging: The Ti80 ingots that have been ground in step S2 are subjected to slab forging and semi-finished and finished forging to obtain Ti80 alloy square billets.

[0112] The specific process is as follows: the Ti80 ingot after grinding in step S2 is placed in a heating furnace, heated and held at 1120℃ for 4 hours, and then transferred to a press for billet forging. The billet forging is completed in three heats, with a total deformation of 85% and a final forging temperature of 1050℃.

[0113] Semi-finished and finished products are forged. The initial forging temperature is 980℃. The forging process of semi-finished and finished products is completed in three forging cycles. The total deformation is 76%. The final forging temperature is 970℃.

[0114] After air cooling, the billet is shaped and milled to obtain a square billet with dimensions of 240mm×1300mm×2400mm.

[0115] S4: Slab pressing: The Ti80 alloy square billet is placed in a heating furnace and heated at 970℃ for 4 hours. Then it is transferred to a 3300mm rolling mill for unidirectional rolling. The rolling is completed in 20 passes at a rolling speed of 6m / s. The total deformation is 87%, and a rolled plate is obtained.

[0116] S5: Annealing treatment: The rolled plate is annealed, then hot-shaped after exiting the furnace, and cooled to obtain the annealed plate; the annealing temperature is 940℃ and the holding time is 2h.

[0117] S6: Fine finishing: The sheet metal is finely finished to obtain Ti80 ultra-wide titanium alloy thick plate.

[0118] The Ti80 ultra-wide titanium alloy thick plate prepared in this embodiment has a size of 45mm×3000mm×6000mm, that is, a thickness of 45mm and a width of 3000mm.

[0119] Table 1 shows the specifications and mechanical properties of the Ti80 ultra-wide titanium alloy thick plates of the embodiments and comparative examples of the present invention; Table 2 shows the microstructure of the Ti80 ultra-wide titanium alloy thick plates of the embodiments and comparative examples of the present invention.

[0120] Table 1. Specifications and mechanical properties of Ti80 ultra-wide titanium alloy thick plates from the examples and comparative examples.

[0121]

[0122]

[0123] Table 2. Microstructure of Ti80 ultra-wide titanium alloy thick plates in the examples and comparative examples.

[0124]

[0125] The composition and preparation method of the Ti80 alloy in Examples 1-3 meet the requirements of this invention. Through the design of reasonable alloy composition, preparation method and strict control of process parameters, Ti80 ultra-wide titanium alloy thick plates were prepared using a wide-width rolling mill. The thickness of the plates can reach 3000mm to 4000mm and 40mm to 80mm. At the same time, they have good mechanical properties, filling the gap in industry. The products have excellent mechanical properties and are suitable for applications in industrial production and shipbuilding.

[0126] The contents of Al, Mo, and Zr in Comparative Example 1 are not within the range required by this invention; the Al and Zr contents are relatively high, while the Mo content is relatively low; since Al is an α-stabilizing element, the proportion of primary α phase in the overall microstructure increases significantly after the Al content increases, which significantly damages the impact performance of the titanium alloy and fails to meet the requirements.

[0127] Comparative Example 2 directly used the ingot from Example 3 for subsequent casting and rolling processes. This comparative example reduced the number of firings in the casting process, increased the speed of the rolling process, and reduced the number of rolling operations, which does not meet the requirements of this invention. Finally, after rolling, severe cracking of the plate was found, and after grinding, it was impossible to obtain an ultra-wide titanium alloy thick plate.

[0128] Comparative Example 3 used a relatively low temperature in the annealing process, which was about 40-50°C below the phase transformation point. Annealing at this temperature resulted in more primary α-phase microstructure, which led to a decrease in the impact performance of the titanium alloy, failing to meet the requirements.

[0129] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a Ti80 ultra-wide titanium alloy thick plate, characterized in that, Includes the following steps: S1: Ingot smelting, using grade zero small-particle sponge titanium, sponge zirconium, aluminum briquettes, and Al. Mo master alloy, Al The Nb master alloy was mixed and pressed into electrodes, and then the resulting electrodes were melted in a vacuum arc furnace three times to obtain Ti80 ingots. S2: Intermediate grinding: Grinding the Ti80 ingot; S3: Slab Forging: The Ti80 ingots ground in step S2 are subjected to slab forging, semi-finished product forging, and finished product forging to obtain Ti80 alloy square billets; the slab forging is divided into three heat treatments, with a total deformation of ≥80%; S4: Slab pressing: The Ti80 alloy square billet is placed in a heating furnace and heated and held at 950~1000℃ for 4~6 hours. Then it is transferred to a rolling mill for unidirectional rolling. The rolling deformation is 60%~90%, the number of unidirectional rolling passes is ≥15, and the rolling speed is ≤8m / s to obtain the rolled plate. S5: Annealing treatment: The rolled plate is annealed, then hot-shaped and cooled after being taken out of the furnace to obtain the annealed plate. S6: Fine finishing: Fine finishing of the sheet material to obtain Ti80 ultra-wide titanium alloy thick plate; In step S3, the initial forging temperature of the semi-finished product and the finished product is 950℃~1000℃, and there are no less than three forging cycles. The total deformation of the semi-finished product and the finished product is ≥70%, and the final forging temperature is ≥960℃. In step S5, the annealing temperature is 960℃~990℃, and the annealing holding time is 1.5~3h; The width of the Ti80 ultra-wide titanium alloy plate is 3000mm~4000mm, and the thickness is 40mm~80mm; The chemical composition of the Ti80 ultra-wide titanium alloy thick plate consists of the following components by weight: Al 5.6%~6.4%, Nb 2.8%~3.2%, Mo 0.9%~1.5%, Zr 1.9%~2.1%, Si ≤0.01%, O ≤0.09%, C ≤0.01%, H ≤0.01%, N ≤0.01%, Fe ≤0.04%, The balance is Ti and unavoidable impurities; The microstructure of the Ti80 ultra-wide titanium alloy thick plate includes a primary α phase and a lamellar transformation β phase, wherein the volume fraction of the lamellar transformation β phase is >35%.

2. The preparation method according to claim 1, characterized in that, In step S4, the unidirectional rolling passes are ≥24.

3. The preparation method according to claim 2, characterized in that, In step S4, the rolling speed of the unidirectional rolling is ≤6m / s.

4. A Ti80 ultra-wide titanium alloy thick plate, prepared by the preparation method according to any one of claims 1-3, characterized in that, The chemical composition of the Ti80 ultra-wide titanium alloy thick plate, by weight, includes: Al 5.6%~6.4%, Nb 2.8%~3.2%, Mo 0.9%~1.5%, Zr 1.9%~2.1%, Si not more than 0.01%, O not more than 0.09%, C not more than 0.01%, H not more than 0.01%, N not more than 0.01%, Fe not more than 0.04%, with the balance being Ti and unavoidable impurities.

5. The Ti80 ultra-wide titanium alloy thick plate according to claim 4, characterized in that, The chemical composition of the Ti80 ultra-wide titanium alloy thick plate, by weight, includes: Al 5.6%~6.2%, Nb 2.9%~3.1%, Mo 0.9%~1.0%, Zr 2.0%~2.1%, Si not more than 0.01%, O not more than 0.06%, C not more than 0.01%, H not more than 0.01%, N not more than 0.01%, Fe not more than 0.04%, with the balance being Ti and unavoidable impurities.

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