A method for manufacturing a low-anisotropy titanium alloy plate

Abstract

The application provides a manufacturing method of a low-anisotropy titanium alloy plate and relates to the technical field of rolling and heat treatment of titanium alloys. The alloy composition is as follows: Al 0.1-11 at%, V 0-5 at%, Mo 0-6 at%, Si 0-0.4 at%, B 0-0.5 at%, Y 0-0.3 at%, and the balance is Ti and inevitable impurities. The manufacturing method of the low-anisotropy titanium alloy plate comprises the following steps: adding different contents of B elements in titanium alloy smelting, and then performing the processes of solidification, hot forging, hot rolling in the alpha recrystallization temperature zone, and heat treatment in the alpha+beta zone, so as to obtain a low-anisotropy high-quality titanium alloy plate. Compared with other traditional methods, the method can efficiently produce the low-anisotropy high-quality cold-rolled titanium alloy plate in a short time by adopting the mode of reasonably controlling the reasonable proportion of alloy elements, combining the rolling process and the heat treatment process, reducing the production energy consumption and the production cost, and the process flow is simple, so that the method is beneficial to industrial large-scale batch production and popularization and use.

Description

Technical Field

[0001] This invention relates to the technical field of rolling and heat treatment of titanium alloys, and particularly to a method for manufacturing titanium alloy sheets with low anisotropy. Background Technology

[0002] Titanium alloys are widely used in aerospace, marine platforms, ships, chemical industry, medical fields and other fields due to their advantages such as high specific strength, low density, good corrosion resistance and strength stability, and non-magnetic properties. They have earned the reputation of "air metal", "third metal", "marine metal" and "smart metal".

[0003] In actual production, titanium alloys are mostly processed by rolling, as thermomechanical processing such as forging, extrusion, and rolling can refine grains, reduce defects, and improve the mechanical properties of titanium alloys. However, rolling or extrusion can lead to anisotropy in titanium alloys, affecting the formability of sheet metal. The presence of anisotropy will have a significant impact on subsequent processing of titanium alloy materials, increasing processing difficulty to a certain extent. Sheet metal may exhibit earing during impact, and its mechanical, corrosion resistance, optical, electromagnetic, and even nuclear physics properties will show significant differences in different directions.

[0004] In general, most rolling processes involve rolling in the same direction. To reduce texture strength, extensive research has focused on reversing the rolling direction to effectively reduce texture strength. However, this rolling method is costly and not conducive to large-scale mass production. Compared with other alloy materials, its forming cost is extremely high, which limits its widespread application in civilian fields such as vehicles, sports and leisure, and construction.

[0005] Chinese patent CN108994077A discloses a rolling method to reduce the anisotropy of TC4 titanium alloy sheet, which combines multiple reversing rolling with heat treatment, accumulating a total of 8 rolling passes. Although this method can achieve the technical goal of reducing the anisotropy of titanium alloy sheet, due to the reversing and multi-pass rolling, it can only be used to produce titanium alloy sheets of a certain size, and the production cost is high, which is not conducive to mass production.

[0006] Chinese patent CN108555281A discloses an additive manufacturing method for reducing anisotropy. This method uses the addition of B powder to prepare titanium alloy additive manufacturing products, which can eliminate the original β columnar grain boundaries, reduce anisotropy, and improve plasticity. After heat treatment, the original columnar grain boundaries disappear, the microstructure becomes uniform and refined, and the anisotropy of the final mechanical properties is reduced. However, this method is aimed at titanium alloys produced by additive manufacturing. The products prepared by this method are different from those prepared by hot rolling and cold rolling in terms of density, porosity defects, and crack defects. In addition, the forming process generates toxic dust, the product strength is limited, there are more defects, the additive manufacturing processing cost is high, and the requirements for experimental instruments and raw materials are high, making it unsuitable for mass production.

[0007] Chinese patent CN111394669A discloses a manufacturing method for reducing the anisotropy of pure titanium sheet and strip for deep drawing. The method involves heating the hot-rolled or cold-rolled titanium sheet and strip to 0-40°C above the β phase transformation temperature, holding it at that temperature for 0.1-10 minutes, cooling it to room temperature, and then applying a final cold rolling deformation in the original rolling direction, followed by recrystallization annealing. Obviously, the yield strength in the TD direction is higher than that in the RD direction, and the elongation after fracture is also higher. The minimum yield strength difference can only reach 26.3 MPa, that is, the yield strength in the RD direction is reduced by at least 13.82% compared to the yield strength in the TD direction. The reduction is still relatively large, and the anisotropy reduction effect is not ideal.

[0008] Chinese patent CN111334731A discloses a method for controlling anisotropy in cold-rolled α+β titanium alloy strip. This method requires one or more rolling passes, intermediate annealing, quenching, 1-2 rolling passes, and final annealing. Obviously, the rolling and heat treatment methods are complex. The elongation of the obtained TC4 titanium alloy strip sample in the RD sampling direction is reduced by 11.54% compared with the TD direction. Moreover, the rolling passes are multiple, the thickness of the rolled product is low, the rolling process is complex to control, and the operation is difficult. Intermediate annealing is required after each rolling pass, and final annealing is performed after the last rolling pass. This method is costly, inefficient, and not suitable for mass production.

[0009] In summary, the high-strength texture of existing titanium alloys caused by the characteristics of the rolling process leads to anisotropy, resulting in many defects in titanium products and limiting their application range. Summary of the Invention

[0010] The technical problem to be solved by the present invention is that the current rolling and heat treatment methods used to eliminate anisotropy in titanium alloy plates are costly, inefficient, complex to control, and difficult to operate. The anisotropy reduction effect is not ideal. In addition, other preparation methods, such as additive manufacturing, have technical defects such as the difference in density, porosity defects, and crack defects between the prepared products and the titanium alloy plates prepared by hot rolling and cold rolling. These methods are not conducive to large-scale mass production.

[0011] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0012] A method for manufacturing a low-anisotropy titanium alloy sheet, wherein the method involves adding different amounts of element B during titanium alloy smelting, followed by solidification, hot forging, hot rolling in the α recrystallization temperature zone, and heat treatment in the α+β zone to obtain a high-quality titanium alloy sheet with low anisotropy.

[0013] Preferably, the composition of the titanium alloy is selected to be near-α type or α+β type, such as TC4 titanium alloy, TA5 titanium alloy, TC11 titanium alloy and other titanium alloys.

[0014] Preferably, the amount of boron added should be selected based on the different titanium alloy compositions and different processes to maximize the grain refinement effect of boron in the titanium alloy and minimize the anisotropy of the titanium alloy sheet.

[0015] Preferably, the mass fraction of the added element B is 0.002-0.08%.

[0016] Preferably, the hot rolling in the α recrystallization temperature zone is carried out through multiple passes to complete the required rolling deformation, thereby obtaining a low anisotropic hot-rolled titanium alloy sheet with an α phase recrystallization percentage of 80% or more.

[0017] Preferably, the process further includes single or multiple cold rolling processes followed by annealing after α+β zone heat treatment.

[0018] Preferably, in the α+β region heat treatment, the proportion of the β phase is controlled at 75-95% during heat treatment, and the temperature is held for 1-20 minutes to control the cooling rate and inhibit martensite formation.

[0019] Preferably, in the single or multiple cold rolling and annealing processes, the deformation amount of the cold rolling is 20-40%, the annealing temperature is 750-820℃, the annealing time is 5-60 min, and then the material is air-cooled to room temperature.

[0020] Preferably, when the sampling direction of the prepared high-quality titanium alloy sheet with low anisotropy is RD, compared with the orientation of TD, the yield strength of RD is reduced by at least 0.923% compared with the yield strength of TD, the tensile strength of RD is reduced by at least 0.632% compared with the tensile strength of TD, and the elongation of RD is increased by at least 7.650% compared with the elongation of TD.

[0021] Preferably, the microstructure of the prepared high-quality titanium alloy sheet with low anisotropy is 75-85% equiaxed α phase, and the average grain size is 10-15 μm; its preparation method greatly shortens the time for controlling the anisotropy of the titanium alloy sheet, reduces production energy consumption and improves production efficiency.

[0022] The above technical solution has at least the following advantages compared with the existing technology:

[0023] In the above-mentioned scheme, the present invention adopts a reasonable ratio of alloying elements to refine the grains of titanium alloy ingots by generating a high-strength ceramic phase TiB during the solidification process. During hot rolling in the α-phase recrystallization temperature range, TiB inhibits the formation of α-phase pyramidal texture, which can reduce or weaken the anisotropy of titanium alloy hot-rolled plates.

[0024] This invention combines rolling and heat treatment processes to maximize the grain-refining effect of boron in titanium alloys containing the optimal proportion (B element), while simultaneously controlling the composition and strength of the texture, resulting in high-quality cold-rolled titanium alloy sheets with low anisotropy.

[0025] The high-quality titanium alloy sheet with low anisotropy prepared by this invention, when sampled in the RD direction, compared with the TD orientation, has a yield strength that is at least 0.923% lower in the RD direction and a tensile strength that is at least 0.632% lower in the RD direction and an elongation that is at least 7.650% higher in the RD direction than in the TD direction.

[0026] The high-quality titanium alloy sheet with low anisotropy prepared by this invention has a microstructure of 75-85% equiaxed α phase and an average grain size of 10-15 μm. Its preparation method greatly shortens the time for controlling the anisotropy of titanium alloy sheet, reduces production energy consumption and improves production efficiency.

[0027] In summary, compared with other traditional methods, the method of the present invention, by adopting a reasonable ratio of alloying elements and combining rolling and heat treatment processes, can produce high-quality cold-rolled titanium alloy sheets with low anisotropy in a short time and with high efficiency, reducing production energy consumption and production costs. The process is simple and conducive to large-scale industrial mass production and widespread use. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 The microstructure of a TC4 titanium alloy with a boron content of 0.04% obtained from a method for manufacturing a low anisotropy titanium alloy sheet according to Embodiment 1 of the present invention is shown in the figure.

[0030] Figure 2 The microstructure of a TC4 titanium alloy with a boron content of 0.04% obtained from a method for manufacturing a low anisotropy titanium alloy sheet according to Embodiment 2 of the present invention is shown in Figure 2.

[0031] Figure 3 This is a microstructure diagram of a TC4 titanium alloy with a boron content of 0.004% obtained from a method for manufacturing a low anisotropy titanium alloy sheet according to Embodiment 3 of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] A method for manufacturing a low-anisotropy titanium alloy sheet; wherein, the content of boron (B) needs to be selected based on different titanium alloy compositions and different processes to maximize the grain-refining effect of boron and minimize the anisotropy of the titanium alloy sheet. In this embodiment, the titanium alloy is TC4 titanium alloy sheet, therefore the content of boron is 0.04%; the manufacturing method of the low-anisotropy titanium alloy sheet is as follows:

[0035] S1: Take a TC4 titanium alloy plate with a B content of 0.04% and a hot forging size of 100mm (length) × 80mm (width) × 10mm (thickness). Place the titanium alloy plate in a heating furnace and heat it at a temperature of 900℃ for 30 minutes.

[0036] S2: The TC4 titanium alloy sheet heated in S1 is transferred to a rolling mill for hot rolling test with a total deformation of 40%. The deformation in each pass is 18-20%. When the temperature drops below 860℃, the resulting billet is sent to an induction heating furnace and heated to 900℃ and held for 15 minutes. The billet is then hot rolled in 2 passes to a thickness of 6 mm to obtain the TC4 titanium alloy sheet of the target thickness. The α phase recrystallization percentage in the TC4 titanium alloy sheet reaches 80%.

[0037] S3: The semi-finished titanium plate in S2 is subjected to α+β recrystallization zone heat treatment. During heat treatment, the proportion of β phase is controlled at 85%, the temperature is controlled at 790℃, and it is held for 20 minutes. Then it is air-cooled to room temperature. During the air-cooling process, the cooling rate needs to be controlled to suppress the formation of martensite, and TC4 hot-rolled titanium alloy plate is obtained.

[0038] The room temperature mechanical properties of the TC4 hot-rolled titanium alloy sheet prepared in this embodiment are shown in Table 1; the microstructure of the TC4 titanium alloy sheet and strip samples obtained in this embodiment is mainly equiaxed.

[0039] In this embodiment, the high-quality titanium alloy sheet with low anisotropy prepared by sampling in the RD direction, compared with the TD orientation, showed that the yield strength in the RD direction decreased by 0.986% and the tensile strength in the RD direction decreased by 0.632% compared with the TD orientation. The elongation in the RD direction increased by at least 7.947% compared with the TD orientation.

[0040] like Figure 1 As shown, the microstructure of the high-quality titanium alloy plate with low anisotropy prepared in this embodiment is 80% equiaxed α phase, 20% β phase, and the average grain size is 12.20 μm.

[0041] This embodiment significantly shortens the time required to control the anisotropy of titanium alloy sheets, reduces production energy consumption, and improves production efficiency.

[0042] Table 1: Mechanical properties of tensile specimens

[0043]

[0044] Example 2

[0045] A method for manufacturing a low-anisotropy titanium alloy sheet; wherein, the content of boron (B) needs to be selected based on different titanium alloy compositions and different processes to maximize the grain-refining effect of boron and minimize the anisotropy of the titanium alloy sheet. In this embodiment, the titanium alloy is TC4 titanium alloy sheet, therefore the content of boron is 0.04%; the manufacturing method of the low-anisotropy titanium alloy sheet is as follows:

[0046] S1: Take a TC4 titanium alloy plate with a B content of 0.04% and a hot forging size of 100mm (length) × 80mm (width) × 10mm (thickness). Place the titanium alloy plate in a heating furnace and heat it at a temperature of 900℃ for 30 minutes.

[0047] S2: The TC4 titanium alloy sheet heated in S1 is transferred to a rolling mill for hot rolling test with a total deformation of 40%. The deformation in each pass is 18-20%. When the temperature drops below 860℃, the resulting billet is sent to an induction heating furnace and heated to 900℃ and held for 15 minutes. The billet is then hot rolled in 2 passes to a thickness of 6 mm to obtain the TC4 titanium alloy sheet of the target thickness. The α phase recrystallization percentage in the TC4 titanium alloy sheet reaches 80%.

[0048] S3: The semi-finished titanium plate in S2 is subjected to α+β recrystallization zone heat treatment. During heat treatment, the proportion of β phase is controlled at 85%, the temperature is controlled at 790℃, and it is held for 20 minutes. Then it is air-cooled to room temperature. During the air-cooling process, the cooling rate needs to be controlled to suppress the formation of martensite, and the first semi-finished plate of TC4 is obtained.

[0049] S4: The first semi-finished TC4 plate from S3 is cold-rolled. The TC4 titanium alloy plate is transferred to a cold rolling mill for the first rolling pass of 3 passes to obtain a TC4 plate with a thickness of 5.4mm.

[0050] S5: Anneal the titanium alloy sheet from S4; after the furnace temperature rises to 790℃, put the TC4 titanium alloy sheet into the heating furnace, hold it for 20 minutes, and then air cool to obtain the second semi-finished TC4 sheet.

[0051] S6: The second semi-finished TC4 plate from S5 is further subjected to cold rolling. The TC4 titanium alloy plate is transferred to a cold rolling mill for a second rolling pass of 3 passes to obtain a TC4 titanium alloy plate with a thickness of 4.5mm.

[0052] S7: The TC4 titanium alloy plate with a thickness of 4.5mm in S6 is subjected to final annealing treatment. After the furnace temperature is raised to 790℃, the TC4 titanium alloy plate is placed in the heating furnace and held for 20 minutes, and then air-cooled to obtain the finished TC4 cold-rolled plate.

[0053] The room temperature mechanical properties of the TC4 hot-rolled titanium alloy sheet prepared in this embodiment are shown in Table 2; the microstructure of the TC4 titanium alloy sheet and strip samples obtained in this embodiment is mainly equiaxed.

[0054] In this embodiment, the high-quality titanium alloy sheet with low anisotropy prepared by sampling in the RD direction, compared with the TD orientation, showed that the yield strength in the RD direction decreased by 0.923% and the tensile strength in the RD direction decreased by 0.788% compared with the TD orientation. The elongation in the RD direction increased by at least 13.514% compared with the TD orientation.

[0055] like Figure 2 As shown, the microstructure of the high-quality titanium alloy plate with low anisotropy prepared in this embodiment is 78% equiaxed α phase, 22% β phase, and the average grain size is 11.60 μm.

[0056] This embodiment significantly shortens the time required to control the anisotropy of titanium alloy sheets, reduces production energy consumption, and improves production efficiency.

[0057] Table 2: Mechanical properties of tensile specimens

[0058]

[0059] Example 3

[0060] A method for manufacturing a low-anisotropy titanium alloy sheet; wherein, the content of boron (B) needs to be selected based on different titanium alloy compositions and different processes to maximize the grain-refining effect of boron and minimize the anisotropy of the titanium alloy sheet. In this embodiment, the titanium alloy is TC4 titanium alloy sheet, therefore the content of boron is 0.004%; the manufacturing method of the low-anisotropy titanium alloy sheet is as follows:

[0061] S1: Take a TC4 titanium alloy plate with a B content of 0.004% and a hot forging size of 100mm (length) × 80mm (width) × 10mm (thickness). Place the titanium alloy plate in a heating furnace and heat it at a temperature of 900℃ for 30 minutes.

[0062] S2: The TC4 titanium alloy sheet heated in S1 is transferred to a rolling mill for hot rolling test with a total deformation of 40%. The deformation in each pass is 18-20%. When the temperature drops below 860℃, the resulting billet is sent to an induction heating furnace and heated to 900℃ and held for 15 minutes. The billet is then hot rolled in 2 passes to a thickness of 6 mm to obtain the TC4 titanium alloy sheet of the target thickness. The α phase recrystallization percentage in the TC4 titanium alloy sheet reaches 75%.

[0063] S3: The semi-finished titanium plate in S2 is subjected to α+β recrystallization zone heat treatment. During heat treatment, the proportion of β phase is controlled at 85%, the temperature is controlled at 790℃, and it is held for 20 minutes. Then it is air-cooled to room temperature. During the air-cooling process, the cooling rate needs to be controlled to suppress the formation of martensite, and the first semi-finished plate of TC4 is obtained.

[0064] S4: The first semi-finished TC4 plate from S3 is cold-rolled. The TC4 titanium alloy plate is transferred to a cold rolling mill for the first rolling pass of 3 passes to obtain a TC4 plate with a thickness of 5.4mm.

[0065] S5: Anneal the titanium alloy sheet from S4; after the furnace temperature rises to 790℃, put the TC4 titanium alloy sheet into the heating furnace, hold it for 20 minutes, and then air cool to obtain the second semi-finished TC4 sheet.

[0066] S6: The second semi-finished TC4 plate from S5 is further subjected to cold rolling. The TC4 titanium alloy plate is transferred to a cold rolling mill for a second rolling pass of 3 passes to obtain a TC4 titanium alloy plate with a thickness of 4.5mm.

[0067] S7: The TC4 titanium alloy plate with a thickness of 4.5mm in S6 is subjected to final annealing treatment. After the furnace temperature is raised to 790℃, the TC4 titanium alloy plate is placed in the heating furnace and held for 20 minutes, and then air-cooled to obtain the finished TC4 cold-rolled plate.

[0068] The room temperature mechanical properties of the TC4 cold-rolled titanium alloy sheet prepared in this embodiment are shown in Table 3; the microstructure of the TC4 titanium alloy sheet and strip samples obtained in this embodiment is mainly equiaxed.

[0069] In this embodiment, the high-quality titanium alloy sheet with low anisotropy prepared by sampling in the RD direction, compared with the TD orientation, showed that the yield strength in the RD direction decreased by 1.852% and the tensile strength in the RD direction decreased by 1.789% compared with the TD orientation. The elongation in the RD direction increased by at least 12.844% compared with the TD orientation.

[0070] like Figure 3 As shown, the microstructure of the high-quality titanium alloy plate with low anisotropy prepared in this embodiment is 78% equiaxed α phase, 22% β phase, and the average grain size is 11.60 μm.

[0071] This embodiment significantly shortens the time required to control the anisotropy of titanium alloy sheets, reduces production energy consumption, and improves production efficiency.

[0072] Table 3: Mechanical properties of tensile specimens

[0073]

[0074] Example 4

[0075] A method for manufacturing a low-anisotropy titanium alloy sheet; wherein, the content of boron (B) needs to be selected based on different titanium alloy compositions and different processes to maximize the grain-refining effect of boron and minimize the anisotropy of the titanium alloy sheet. In this embodiment, the titanium alloy is TA5 titanium alloy sheet, therefore the content of boron is 0.04%; the manufacturing method of the low-anisotropy titanium alloy sheet is as follows:

[0076] S1: Take a TA5 titanium alloy plate with a B content of 0.04% and a hot forging size of 100mm (length) × 80mm (width) × 10mm (thickness). Place the titanium alloy plate in a heating furnace and heat it at a temperature of 900℃ for 30 minutes.

[0077] S2: The TA5 titanium alloy sheet heated in S1 is transferred to the rolling mill for a hot rolling test with a total deformation of 40%. The deformation in each pass is 18-20%. When the temperature drops below 860℃, the resulting billet is sent to an induction heating furnace and heated to 900℃. It is then held for 15 minutes and hot rolled for 2 passes to a sheet with a thickness of 6mm to obtain the TA5 titanium alloy sheet of the target thickness.

[0078] S3: The semi-finished titanium plate in S2 is subjected to recrystallization zone heat treatment at a temperature of 680℃ and held for 20 minutes. Then it is air-cooled to room temperature. During the air-cooling process, the cooling rate needs to be controlled to suppress the formation of martensite, and the first semi-finished TA5 plate is obtained.

[0079] S4: The first semi-finished TA5 plate from S3 is cold rolled. The TA5 titanium alloy plate is transferred to a cold rolling mill for the first rolling of three passes to obtain a TA5 plate with a thickness of 5mm.

[0080] S5: Anneal the TA5 sheet material from S4; after the furnace temperature rises to 700℃, put the TA5 titanium alloy sheet material into the heating furnace, hold it for 20 minutes, and then air cool it to obtain the second semi-finished TA5 sheet material.

[0081] S6: The second semi-finished TA5 plate from S5 is further subjected to cold rolling. The TA5 titanium alloy plate is moved to a cold rolling mill for a second rolling process of 3 passes to obtain a TA5 titanium alloy plate with a thickness of 4mm.

[0082] S7: The 4mm thick TA5 titanium alloy plate from S6 is subjected to final annealing. After the furnace temperature rises to 700℃, the TA5 titanium alloy plate is placed in the heating furnace and held for 20 minutes, followed by air cooling to obtain the finished TA5 cold-rolled sheet.

[0083] The room temperature mechanical properties of the TA5 hot-rolled titanium alloy sheet prepared in this embodiment are shown in Table 4; the microstructure of the TA5 titanium alloy sheet and strip samples obtained in this embodiment is mainly equiaxed.

[0084] In this embodiment, the high-quality titanium alloy sheet with low anisotropy prepared by sampling in the RD direction, compared with the TD orientation, showed that the yield strength in the RD direction decreased by 2.309% and the tensile strength in the RD direction decreased by 1.766% compared with the TD orientation. The elongation in the RD direction increased by at least 7.650% compared with the TD orientation.

[0085] The high-quality titanium alloy sheet with low anisotropy prepared in this embodiment has an equiaxed α phase microstructure and an average grain size of 8.5 μm.

[0086] This embodiment significantly shortens the time required to control the anisotropy of titanium alloy sheets, reduces production energy consumption, and improves production efficiency.

[0087] Table 4: Mechanical properties of tensile specimens

[0088]

[0089] In the above-mentioned scheme, the present invention adopts a reasonable ratio of alloying elements to refine the grains of titanium alloy ingots by generating a high-strength ceramic phase TiB during the solidification process. During hot rolling in the α-phase recrystallization temperature range, TiB inhibits the formation of α-phase pyramidal texture, which can reduce or weaken the anisotropy of titanium alloy hot-rolled plates.

[0090] This invention combines rolling and heat treatment processes to maximize the grain-refining effect of boron in titanium alloys containing the optimal proportion (B element), while simultaneously controlling the composition and strength of the texture, resulting in high-quality cold-rolled titanium alloy sheets with low anisotropy.

[0091] The high-quality titanium alloy sheet with low anisotropy prepared by this invention, when sampled in the RD direction, compared with the TD orientation, has a yield strength that is at least 0.923% lower in the RD direction and a tensile strength that is at least 0.632% lower in the RD direction and an elongation that is at least 7.650% higher in the RD direction than in the TD direction.

[0092] The high-quality titanium alloy sheet with low anisotropy prepared by this invention has a microstructure of 75-85% equiaxed α phase and an average grain size of 10-15 μm. Its preparation method greatly shortens the time for controlling the anisotropy of titanium alloy sheet, reduces production energy consumption and improves production efficiency.

[0093] In summary, compared with other traditional methods, the method of the present invention, by adopting a reasonable ratio of alloying elements and combining rolling and heat treatment processes, can produce high-quality cold-rolled titanium alloy sheets with low anisotropy in a short time and with high efficiency, reducing production energy consumption and production costs. The process is simple and conducive to large-scale industrial mass production and widespread use.

[0094] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for manufacturing a low-anisotropy titanium alloy sheet, characterized in that, The method for manufacturing the low anisotropy titanium alloy sheet is to add different amounts of element B during titanium alloy smelting, followed by solidification, hot forging, hot rolling in the α recrystallization temperature zone, and heat treatment in the α+β zone to obtain a high-quality titanium alloy sheet with low anisotropy. The amount of boron added should be selected based on the different titanium alloy compositions and different processes to maximize boron's role in refining the grains and minimizing the anisotropy of the titanium alloy sheet. The mass fraction of the added element B varies from 0.002% to 0.08%. The microstructure of the prepared high-quality titanium alloy plate with low anisotropy is 75-85% equiaxed α phase, and the average grain size is 10-15 μm. In the α+β region heat treatment, the proportion of the β phase is controlled at 75-95% during heat treatment, and the temperature is held for 1-20 minutes to control the cooling rate and inhibit martensite formation.

2. The method for manufacturing low anisotropy titanium alloy sheet according to claim 1, characterized in that, The titanium alloy is selected as a near-α type or α+β type titanium alloy.

3. The method for manufacturing low anisotropy titanium alloy sheet according to claim 1, characterized in that, The hot rolling process in the α recrystallization temperature zone completes the required rolling deformation through multiple passes, resulting in a low anisotropic hot-rolled titanium alloy sheet with an α phase recrystallization percentage of 80% or higher.

4. The method for manufacturing low anisotropy titanium alloy sheet according to claim 1, characterized in that, The process also includes single or multiple cold rolling processes followed by annealing after α+β zone heat treatment.

5. The method for manufacturing low anisotropy titanium alloy sheet according to claim 1, characterized in that, In the single or multiple cold rolling and annealing processes, the deformation amount of cold rolling is 20-40%, the annealing temperature is 750-820℃, the annealing time is 5-60min, and then it is air-cooled to room temperature.

6. The method for manufacturing a low-anisotropy titanium alloy sheet according to claim 1, characterized in that, When the sampling direction of the prepared high-quality titanium alloy sheet with low anisotropy is RD, compared with the orientation of TD, the yield strength of RD is reduced by at least 0.923% compared with the yield strength of TD, the tensile strength of RD is reduced by at least 0.632% compared with the tensile strength of TD, and the elongation of RD is increased by at least 7.650% compared with the elongation of TD.

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