Titanium alloy bar and preparation method thereof

Abstract

The invention relates to the technical field of titanium alloy material processing, and discloses a titanium alloy bar and a preparation method thereof.The preparation method comprises the following steps that S1, metal raw materials are mixed and then smelted, and a titanium alloy cast ingot with the aluminum content being 6.7-7.1 wt% and the oxygen content being 0.12-0.15 wt% is obtained; the metal raw materials contain titanium and aluminum; and S2, the titanium alloy cast ingot is subjected to at least three times of upsetting and drawing and at least one time of rolling. The titanium alloy bar has high elastic modulus and strength at the room temperature and the temperature of 300 DEG C.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy material processing, and in particular to a titanium alloy bar and a preparation method thereof. Background Art

[0002] The nominal composition of TA15 titanium alloy is Ti-6Al-2Zr-1Mo-1V. It is a near-α-type titanium alloy with high aluminum equivalent and can be used for a long time at 450~500℃. With the change of service conditions of materials, higher requirements are put forward for the room temperature and 300℃ high temperature strength and elastic modulus of materials. It is necessary to meet the room temperature elastic modulus ≥109GPa, tensile strength ≥930MPa, yield strength ≥855MPa, elongation ≥10% at room temperature; 300℃ elastic modulus ≥100GPa, tensile strength ≥750MPa, yield strength ≥550MPa, elongation ≥15%. The existing conventional process adopts the single-phase and two-phase region multi-fire upsetting of TA15 ingots meeting GB / T3620.1-2016 "Titanium and Titanium Alloy Grades and Chemical Compositions" and then forms them through fast forging machines, precision forging machines and other forming equipment. The elastic modulus and strength of TA15 bars prepared by the above method often cannot meet the technical index requirements. Summary of the invention

[0003] The purpose of the present invention is to overcome the problem that the elastic modulus and strength of TA15 rods in the prior art cannot meet the requirements of technical indicators, and to provide a titanium alloy rod and a preparation method thereof, wherein the titanium alloy rod has a high elastic modulus and strength at room temperature and at a temperature of 300°C.

[0004] In order to achieve the above object, the present invention provides a first aspect of a method for preparing a titanium alloy bar, comprising the following steps: S1. Mixing metal raw materials and smelting them to obtain a titanium alloy ingot having an aluminum content of 6.7-7.1wt% and an oxygen content of 0.12-0.15wt%; the metal raw materials contain titanium and aluminum; S2. performing at least three upsetting and at least one rolling on the titanium alloy ingot.

[0005] Preferably, in step S1, the metal raw material also contains zirconium, molybdenum and vanadium.

[0006] Preferably, in the titanium alloy ingot, the zirconium content is 2-2.5wt%, the molybdenum content is 1.5-2wt%, the vanadium content is 2-2.5wt%, and the balance is titanium.

[0007] Preferably, in the titanium alloy ingot, the mass ratio of the aluminum to the oxygen is 1:0.016-0.023.

[0008] Preferably, the smelting conditions at least include: a smelting current of 12-32KA, a smelting voltage of 28-43V, an arc stabilization current of 10-30A, and a commutation frequency of 10-20 seconds / time.

[0009] Preferably, the upsetting includes a first upsetting, a second upsetting and a third upsetting; The first upsetting process includes diagonal upsetting followed by elongation, and the conditions of the first upsetting include at least: a temperature of 1000-1200°C; The second upsetting is roughening, and the conditions of the second upsetting include at least: the temperature is T β -70 to T β -50℃; The third upsetting process includes upsetting and then lengthening, and the conditions of the third upsetting include at least: the temperature is T β -70 to T β -50℃; Among them, T β is the phase transition temperature of the titanium alloy ingot.

[0010] Further preferably, in the first upsetting, the diagonal drawing is performed 2-3 times, and the single deformation is 19-36%; and / or The conditions of the second upsetting also include: an upsetting ratio of 2.5-3.5; and / or The third upsetting is performed 2-4 times, and the single deformation is 30-50%.

[0011] More preferably, the method further comprises: after the second upsetting, heating to T β +20 to T β After +50℃, keep warm for 120-240min.

[0012] Preferably, the rolling conditions include at least: a temperature of T β -90 to T β -50℃, the total deformation of the rolling is 50-75%.

[0013] A second aspect of the present invention provides a titanium alloy rod prepared by the above preparation method.

[0014] Through the above technical scheme, the method for preparing titanium alloy rods provided by the present invention is to obtain a titanium alloy ingot with an aluminum content of 6.7-7.1wt% and an oxygen content of 0.12-0.15wt% by smelting metal raw materials, and subjecting the ingot to at least three upsetting and at least one rolling, so that the obtained titanium alloy rod has a higher elastic modulus, tensile strength and yield strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 EBSD diagram of the rod prepared in Example 1, wherein from left to right are the {0001}, {10-10}, and {11-22} crystal plane distribution diagrams of the rod head structure; Figure 2 EBSD diagram of the rod prepared in Example 2, wherein from left to right are the {0001}, {10-10}, and {11-22} crystal plane distribution diagrams of the rod head structure; Figure 3 This is the EBSD image of the rod prepared in Example 3, where from left to right are the {0001}, {10-10}, and {11-22} crystal plane distribution images of the rod head structure. DETAILED DESCRIPTION

[0016] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0017] As mentioned above, the present invention provides a method for preparing a titanium alloy bar, comprising the following steps: S1. Mixing metal raw materials and smelting them to obtain a titanium alloy ingot having an aluminum content of 6.7-7.1wt% and an oxygen content of 0.12-0.15wt%; the metal raw materials contain titanium and aluminum; S2. performing at least three upsetting and at least one rolling on the titanium alloy ingot.

[0018] According to the present invention, the metal raw material can be any raw material containing titanium and aluminum. Exemplarily, the metal raw material providing the titanium element can be at least one of titanium metal, titanium sponge and titanium dioxide; the metal raw material providing the aluminum raw material can be selected from at least one of aluminum metal, aluminum molybdenum and aluminum vanadium. Preferably, the metal raw material providing the titanium element is titanium sponge and / or titanium dioxide; the aluminum metal is aluminum beans.

[0019] According to the present invention, the aluminum and oxygen contents in the titanium alloy ingot are detected according to GB / T4698.

[0020] During the research process, the inventors found that by first mixing the metal raw materials and then smelting them to obtain a titanium alloy ingot with an aluminum content of 6.7-7.1wt% and an oxygen content of 0.12-0.15wt%, and then subjecting the titanium alloy ingot to at least three upsettings and at least one rolling, the aluminum and oxygen elements of the above contents are dissolved in the α lattice as substitutional and interstitial elements, respectively, which can effectively enhance the interatomic bonding force, thereby improving the strength and elastic modulus of the material, and further improving the elastic modulus, tensile strength and yield strength of the prepared titanium alloy rod.

[0021] In addition, the present invention can use conventional raw materials for smelting and has a simple deformation method, thereby achieving improvements in the strength and elastic modulus of the rod without introducing additional production costs.

[0022] According to the present invention, in the titanium alloy ingot, the aluminum content can be 6.7wt%, 6.8wt%, 6.9wt%, 7.0wt%, 7.1wt%, or any value within the ranges formed by these values; the oxygen content can be 0.12wt%, 0.13wt%, 0.14wt%, 0.15wt%, or any value within the ranges formed by these values.

[0023] Preferably, in step S1, the metal raw material further contains zirconium, molybdenum and vanadium. Studies have found that the metal raw material also contains zirconium, molybdenum and vanadium, which can further improve the elastic modulus, tensile strength and yield strength of the rod.

[0024] According to the present invention, illustratively, the metal raw material providing the zirconium element may be sponge zirconium; the metal raw material providing the molybdenum element may be aluminum molybdenum; and the metal raw material providing the vanadium element may be aluminum vanadium.

[0025] Preferably, in the titanium alloy ingot, the zirconium content is 2-2.5wt%, which can be 2wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, or any value between these numerical ranges; the molybdenum content is 1.5-2wt%, which can be 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2wt%, or any value between these numerical ranges; the vanadium content is 2-2.5wt%, which can be 2wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, or any value between these numerical ranges. Controlling the contents of zirconium, molybdenum and vanadium in the titanium alloy ingot within the above range can further improve the elastic modulus, tensile strength and yield strength of the obtained titanium alloy bar.

[0026] According to the present invention, the contents of zirconium, molybdenum and vanadium in the titanium alloy ingot are tested according to GB / T4698.

[0027] Preferably, in the titanium alloy ingot, the mass ratio of the aluminum to the oxygen is 1:0.016-0.023, which may be 1:0.016, 1:0.017, 1:0.018, 1:0.019, 1:0.02, 1:0.021, 1:0.022, 1:0.023, or any value within the range formed by these ratios. Studies have found that controlling the mass ratio of aluminum to oxygen within the above range can further improve the elastic modulus, tensile strength and yield strength of the obtained titanium alloy bar.

[0028] Preferably, the smelting conditions at least include: the smelting current is 12-32KA, which can be 12KA, 16KA, 20KA, 24KA, 28KA, 32KA, or any value within the range formed by these values; the smelting voltage is 28-43V, the arc stabilization current is 10-30A, and the commutation frequency is 10-20 seconds / time. Under the above conditions, the content of aluminum and oxygen in the titanium alloy ingot can be better controlled, and the elastic modulus, tensile strength and yield strength of the obtained titanium alloy bar can be further improved.

[0029] Preferably, the method further comprises: after mixing, pressing the metal raw materials into blocks.

[0030] In order to achieve better smelting effect, preferably, the smelting is repeated 2-4 times.

[0031] Preferably, the upsetting includes a first upsetting, a second upsetting and a third upsetting; the process of the first upsetting includes diagonal elongation after upsetting, and the conditions of the first upsetting include at least: a temperature of 1000-1200°C, which can be 1000°C, 1020°C, 1040°C, 1060°C, 1080°C, 1100°C, 1120°C, 1140°C, 1160°C, 1180°C, 1200°C, or any value within the range formed by these temperatures; the second upsetting is upsetting, and the conditions of the second upsetting include at least: a temperature of T β -70 to T β -50℃, can be T β -70℃、T β -66℃、T β -62℃、T β -58℃、T β -54℃、T β -50°C, or any value within the range formed by these temperatures; the third upsetting process includes upsetting and then drawing, and the conditions of the third upsetting at least include: the temperature is T β -70 to T β -50℃, can be T β -70℃、Tβ -66℃、T β -62℃、T β -58℃、T β -54℃、T β -50℃, or any value within the range formed by these temperatures. The diagonal stretching in the first upsetting can quickly break the β grains and destroy the orientation relationship inside the α cluster formed in the high-temperature cooling stage, providing nucleation points for the nucleation of the high-temperature β phase and subsequent upsetting at the phase transformation point, further refining and homogenizing the β grains, so that the obtained titanium alloy rod has a higher elastic modulus, tensile strength and yield strength.

[0032] Among them, T β is the phase transition temperature of titanium alloy ingot.

[0033] Preferably, in the first upsetting, the diagonal drawing is performed 2-3 times, and the single deformation is 19-36%, which can be 19%, 22%, 25%, 28%, 31%, 34%, 36%, or any value within the range formed by these values. Studies have found that controlling the diagonal drawing of the first upsetting within the above range can further improve the elastic modulus, tensile strength and yield strength of the prepared titanium alloy bar.

[0034] Preferably, the conditions of the second upsetting also include: an upsetting ratio of 2.5-3.5, which can be 2.5, 2.7, 2.9, 3.1, 3.3, 3.5, or any value within the range formed by these values. Controlling the upsetting ratio of the second upsetting to 2.5-3.5 can further improve the elastic modulus, tensile strength and yield strength of the prepared titanium alloy bar.

[0035] Preferably, the second upsetting is performed twice, and the directions of the two upsettings are different.

[0036] Preferably, the third upsetting is performed 2-4 times, and the single deformation is 30-50%, which can be 30%, 34%, 38%, 42%, 46%, 50%, or any value within the range formed by these values. Under the above conditions, the elastic modulus, tensile strength and yield strength of the obtained titanium alloy bar can be further improved.

[0037] Preferably, the method further comprises: after the second upsetting, heating to T β +20 to T β The above steps can further improve the elastic modulus, tensile strength and yield strength of the prepared titanium alloy rod.

[0038] Preferably, the rolling conditions include at least: a temperature of T β -90 to T β-50°C, the total deformation of the rolling is 50-75%, which can further improve the elastic modulus, tensile strength and yield strength of the titanium alloy bar.

[0039] Preferably, the method further comprises: before upsetting, cutting off the riser and the bottom of the titanium alloy ingot, so that the obtained rod is more uniform.

[0040] Preferably, the method further comprises annealing the rolled bar material, in order to further improve the elastic modulus, tensile strength and yield strength of the bar material, preferably, the annealing temperature is 650-750°C.

[0041] In addition, the present invention also provides a titanium alloy rod prepared by the above preparation method. The titanium alloy rod has a high elastic modulus, tensile strength and yield strength.

[0042] Preferably, the elastic modulus of the titanium alloy rod at 25°C is 106-130 GPa, the tensile strength is 980-1070 MPa, and the yield strength is 910-960 MPa; the elastic modulus of the titanium alloy rod at 300°C is 100-118 GPa, the tensile strength is 760-840 MPa, and the yield strength is 610-660 MPa.

[0043] According to the present invention, the elastic modulus is tested according to GB / T22315 standard, and the tensile strength and yield strength are tested according to GB / T228.1.

[0044] Preferably, the diameter of the titanium alloy rod is 80-120 mm.

[0045] According to a particularly preferred embodiment of the present invention, a method for preparing a titanium alloy bar is provided, comprising the following steps: S1. After sponge titanium, aluminum beans, titanium dioxide, sponge zirconium, aluminum molybdenum and aluminum vanadium are mixed and pressed into electrode blocks, they are smelted three times under the smelting conditions of 12-32KA, 28-43V, 10-30A arc stabilization current and 10-20 seconds / time in the stable stage to obtain a titanium alloy ingot with an aluminum content of 6.7-7.1wt%, an oxygen content of 0.12-0.15wt%, a zirconium content of 2-2.5wt%, a molybdenum content of 1.5-2wt%, a vanadium content of 2-2.5wt%, and a balance of titanium; in the titanium alloy ingot, the mass ratio of aluminum to oxygen is 1:0.016-0.023.

[0046] S2. After cutting off the riser and the bottom of the titanium alloy ingot obtained in step S1, upsetting is performed once at 1150° C. (upsetting ratio is 1.7-1.8), and then diagonally stretching is performed three times to obtain a first billet, and the single deformation amount of diagonal stretching is 19-36%.

[0047] S3, the first blank obtained in step S2 is placed at the phase transition point T β -70 to T β -50℃, upsetting ratio of 2.5-3.5, and then heating to T β +20 to T β +50℃ back to the furnace for 120-240min, after coming out of the furnace, at the phase transition point T β -70 to T β The second blank is obtained by side upsetting at -50°C and upsetting at 2.5-3.5, and then water cooling.

[0048] S4, the second blank obtained in step S3 is placed at the phase transition point T β -70 to T β The upsetting and drawing process is performed at -50°C with an upsetting ratio of 1.6-1.8, and the upsetting and drawing process is repeated 2-4 times before direct drawing. The single deformation amount during the drawing process is controlled to be 30-50%, thereby obtaining a third blank.

[0049] S5, the third blank obtained in step S4 is placed at the phase transition point T β -90 to T β The TA15 titanium alloy bar is rolled and deformed at -50°C to obtain a TA15 titanium alloy bar with a diameter of 80-120 mm, and the deformation amount during the rolling process is controlled to be 50-75%.

[0050] Through the above preparation method, a titanium alloy ingot with an aluminum content of 6.7-7.1wt% and an oxygen content of 0.12-0.15wt% is obtained by smelting a metal raw material, and the ingot is subjected to at least three upsetting and at least one rolling, so that the obtained titanium alloy bar has a high elastic modulus, tensile strength and yield strength. Further controlling the zirconium content, molybdenum content, vanadium content and the mass ratio of oxygen to titanium in the titanium alloy ingot can further improve the elastic modulus, tensile strength and yield strength of the obtained titanium alloy bar.

[0051] The β grains are quickly broken by axial diagonal pulling in the ingot casting stage, and then the orientation relationship inside the α cluster formed in the high-temperature cooling stage is destroyed by a second upsetting with a large upsetting ratio, so as to provide a nucleation point for the nucleation of the high-temperature β phase and then perform a third upsetting at the phase transformation point to further refine and homogenize the β grains. Finally, the final water cooling is adopted at the phase transformation point to precipitate thinner α sheets with relatively random orientation, so as to provide a good original organization for the subsequent uniform and fine equiaxed α phase, thereby further improving the elastic modulus, tensile strength and yield strength of the prepared titanium alloy bar.

[0052] Since a continuous grain boundary α phase that is seriously detrimental to plasticity will precipitate when the titanium alloy is cooled from β→α+β, multiple deformations are often required to fully break up the grain boundary α phase. However, during the multiple heating processes, the α phase will be affected by the thermal driving force and will spheroidize and grow, reducing the strength of the material. At the same time, excessive deformation will cause the material to undergo an α→β dynamic phase transition during the deformation process and a β→α reverse transition during the subsequent cooling or remelting and heat preservation process, increasing the α phase grain size. The present invention shortens the high-temperature heating time to reduce the size of the α phase by a second upsetting and remelting forging, and finally obtains a fine-sized α phase on the basis of sufficient grain boundary breakage, thereby further improving the tensile strength and yield strength of the prepared titanium alloy rod.

[0053] The present invention adopts a high-speed deformation mode of rolling deformation, controls the temperature and deformation amount at the same time, obtains a texture orientation with a smaller angle between the c-axis and the loading direction, and further improves the elastic modulus of the bar.

[0054] In addition, the low-temperature limited deformation + low-temperature rolling bar preparation process adopted by the present invention has a simple process and can significantly reduce production costs compared to the conventional process of refining grains through multiple upsetting and drawing.

[0055] The present invention will be described in detail below through examples. In the following examples, aluminum molybdenum is a commercially available product with a grade of AlMo65, with an aluminum content of 34.94wt% and a molybdenum content of 64.89wt%; aluminum vanadium is a commercially available product with a grade of AlV55, with an aluminum content of 41.14wt% and a vanadium content of 58.53wt%.

[0056] Example 1 S1. 224kg of sponge titanium, 10.1kg of aluminum beans, 0.78kg of titanium dioxide, 6.48kg of sponge zirconium, 7.89kg of aluminum molybdenum and 10.95kg of aluminum vanadium were mixed and pressed into electrode blocks, and then smelted three times under the conditions of smelting current of 20KA, smelting voltage of 35V, arc stabilization current of 20A and commutation frequency of 15 seconds / time in the stable stage to obtain a titanium alloy ingot with an aluminum content of 6.7wt%, an oxygen content of 0.15wt%, a zirconium content of 2.45wt%, a molybdenum content of 1.98wt% and a vanadium content of 2.48wt%.

[0057] S2, cutting off the riser and the bottom of the ingot obtained in step S1, upsetting it once at 1150° C., and then diagonally stretching it three times to obtain a first billet.

[0058] S3, the first blank obtained in step S2 is placed at the phase transition point T β -70℃(T β =1010℃), upsetting ratio of 3.5, and then heating to T β+50℃ back to the furnace for 240min, after coming out of the furnace, at the phase transition point T β Lateral upsetting was performed at -70℃ and upsetting ratio was 3.5, followed by water cooling.

[0059] S4, the second blank obtained in step S3 is placed at the phase transition point T β After an upsetting and drawing process at -70°C, the product is returned to the furnace and then directly drawn after another upsetting and drawing process. The single deformation amount during the drawing process is controlled to be 50%, and the third billet is obtained.

[0060] S5, the third blank obtained in step S4 is placed at the phase transition point T β The TA15 titanium alloy bar with a diameter of 100 mm was obtained by rolling deformation at -50°C, and the deformation amount during the rolling process was controlled to be 75%.

[0061] Example 2 S1. 223kg of sponge titanium, 12.3kg of aluminum beans, 0.6kg of titanium dioxide, 5.43kg of sponge zirconium, 6.21kg of aluminum molybdenum and 9.27kg of aluminum vanadium are mixed and pressed into electrode blocks, and then smelted 4 times under the conditions of smelting current of 12KA, smelting voltage of 28V, arc stabilization current of 10A and commutation frequency of 20 seconds / time in the stable stage to obtain a titanium alloy ingot with an aluminum content of 7.1wt%, an oxygen content of 0.12wt%, a zirconium content of 2.05wt%, a molybdenum content of 1.56wt% and a vanadium content of 2.03wt%.

[0062] S2, cutting off the riser and the bottom of the ingot obtained in step S1, upsetting it once at 1150° C., and then diagonally stretching it three times to obtain a first billet.

[0063] S3, the first blank obtained in step S2 is placed at the phase transition point T β -60℃(T β =998℃), upsetting ratio of 3, and then heating to T β +40℃ back to the furnace for 150min, after coming out of the furnace, at the phase transition point T β Reversing upsetting and drawing at -60℃ and upsetting ratio of 3, followed by water cooling.

[0064] S4, the second blank obtained in step S3 is placed at the phase transition point T β After an upsetting and drawing process at -50°C, the product is returned to the furnace and then directly drawn after another upsetting and drawing process. The single deformation amount during the drawing process is controlled to be 30%, and the third billet is obtained.

[0065] S5, the third blank obtained in step S4 is placed at the phase transition point T β The TA15 titanium alloy bar with a diameter of 120 mm was obtained by performing a rolling deformation at -75°C, and the deformation amount during the rolling process was controlled to be 60%.

[0066] Example 3 S1. 224kg of sponge titanium, 11kg of aluminum beans, 0.66kg of titanium dioxide, 6kg of sponge zirconium, 6.42kg of aluminum molybdenum and 10.56kg of aluminum vanadium were mixed and pressed into electrode blocks, and then smelted twice under the conditions of smelting current of 32KA, smelting voltage of 43V, arc stabilization current of 30A and commutation frequency of 10 seconds / time in the stable stage to obtain a titanium alloy ingot with an aluminum content of 6.9wt%, an oxygen content of 0.13wt%, a zirconium content of 2.27wt%, a molybdenum content of 1.67wt% and a vanadium content of 2.23wt%.

[0067] S2, cutting off the riser and the bottom of the ingot obtained in step S1, upsetting it once at 1150° C., and then diagonally stretching it twice to obtain a first billet.

[0068] S3, the first blank obtained in step S2 is placed at the phase transition point T β -50℃(T β =1005℃), upsetting ratio of 2.5, and then heating to T β +20℃ back to the furnace for 120min, after coming out of the furnace, at the phase transition point T β Lateral upsetting was performed at -50℃ and upsetting ratio was 2.5, followed by water cooling.

[0069] S4, the second blank obtained in step S3 is placed at the phase transition point T β After an upsetting and drawing process at -60°C, the product is returned to the furnace and then directly drawn after another upsetting and drawing process. The single deformation amount during the drawing process is controlled to be 44%, and the third billet is obtained.

[0070] S5, the third blank obtained in step S4 is placed at the phase transition point T β The TA15 titanium alloy bar with a diameter of 100 mm was obtained by rolling deformation once at -90°C, and the deformation amount during the rolling process was controlled to be 50%.

[0071] Example 4 A titanium alloy rod is prepared according to the method of Example 1, except that in step S1, the addition amounts of sponge titanium, aluminum beans, titanium dioxide, sponge zirconium, aluminum molybdenum and aluminum vanadium raw materials are adjusted to obtain a titanium alloy ingot with an aluminum content of 6.7wt%, an oxygen content of 0.12wt%, a zirconium content of 2.45wt%, a molybdenum content of 1.98wt% and a vanadium content of 2.48wt%.

[0072] Example 5 A titanium alloy rod is prepared according to the method of Example 2, except that in step S1, the addition amounts of sponge titanium, aluminum beans, titanium dioxide, sponge zirconium, aluminum molybdenum and aluminum vanadium raw materials are adjusted to obtain a titanium alloy ingot with an aluminum content of 7.1wt%, an oxygen content of 0.15wt%, a zirconium content of 2.05wt%, a molybdenum content of 1.56wt% and a vanadium content of 2.03wt%.

[0073] Example 6 A titanium alloy rod is prepared according to the method of Example 1, except that in step S1, the addition amounts of sponge titanium, aluminum beans, titanium dioxide, sponge zirconium, aluminum molybdenum and aluminum vanadium raw materials are adjusted to obtain a titanium alloy ingot with an aluminum content of 6.7wt%, an oxygen content of 0.15wt%, a zirconium content of 1.93wt%, a molybdenum content of 1.44wt% and a vanadium content of 1.89wt%.

[0074] Example 7 A titanium alloy rod is prepared according to the method of Example 2, except that in step S1, the addition amounts of sponge titanium, aluminum beans, titanium dioxide, sponge zirconium, aluminum molybdenum and aluminum vanadium raw materials are adjusted to obtain a titanium alloy ingot with an aluminum content of 7.1wt%, an oxygen content of 0.12wt%, a zirconium content of 2.55wt%, a molybdenum content of 2.12wt% and a vanadium content of 2.14wt%.

[0075] Example 8 A titanium alloy rod is prepared according to the method of Example 1, except that in step S3, the upsetting ratio is 4.

[0076] Example 9 A titanium alloy rod is prepared according to the method of Example 3, except that in step S3, the upsetting ratio is 2.

[0077] Example 10 The titanium alloy rod is prepared according to the method of Example 1, except that in step S3, the temperature is T β +70℃(T β =1010℃).

[0078] Embodiment 11 The titanium alloy rod is prepared according to the method of Example 1, except that in step S4, the temperature is T β +70℃(T β =1010℃).

[0079] Example 12 The titanium alloy rod is prepared according to the method of Example 1, except that step S3 comprises: β -70℃(T β=1010℃) and upsetting ratio of 3.5. After upsetting, at the phase transition point T β Lateral upsetting was performed at -70℃ and upsetting ratio was 3.5, followed by water cooling.

[0080] Comparative Example 1 A titanium alloy rod is prepared according to the method of Example 1, except that in step S1, the addition amounts of sponge titanium, aluminum beans, titanium dioxide, sponge zirconium, aluminum molybdenum and aluminum vanadium raw materials are adjusted to obtain a titanium alloy ingot with an aluminum content of 6.5wt%, an oxygen content of 0.15wt%, a zirconium content of 2.45wt%, a molybdenum content of 1.98wt% and a vanadium content of 2.48wt%.

[0081] Comparative Example 2 A titanium alloy rod is prepared according to the method of Example 1, except that in step S1, the addition amounts of sponge titanium, aluminum beans, titanium dioxide, sponge zirconium, aluminum molybdenum and aluminum vanadium raw materials are adjusted to obtain a titanium alloy ingot with an aluminum content of 6.7wt%, an oxygen content of 0.17wt%, a zirconium content of 2.45wt%, a molybdenum content of 1.98wt% and a vanadium content of 2.48wt%.

[0082] Comparative Example 3 A titanium alloy rod is prepared according to the method of Example 2, except that in step S1, the addition amounts of sponge titanium, aluminum beans, titanium dioxide, sponge zirconium, aluminum molybdenum and aluminum vanadium raw materials are adjusted to obtain a titanium alloy ingot with an aluminum content of 7.3wt%, an oxygen content of 0.12wt%, a zirconium content of 2.05wt%, a molybdenum content of 1.56wt% and a vanadium content of 2.03wt%.

[0083] Comparative Example 4 A titanium alloy rod is prepared according to the method of Example 2, except that in step S1, the addition amounts of sponge titanium, aluminum beans, titanium dioxide, sponge zirconium, aluminum molybdenum and aluminum vanadium raw materials are adjusted to obtain a titanium alloy ingot with an aluminum content of 7.1wt%, an oxygen content of 0.1wt%, a zirconium content of 2.05wt%, a molybdenum content of 1.56wt% and a vanadium content of 2.03wt%.

[0084] Test Example 1 The prepared titanium alloy rods were subjected to ordinary annealing at 700℃ and tested for mechanical properties. The mechanical properties are shown in Tables 1-2 and Figure 1-3 The mechanical properties at room temperature (25°C) are shown in Table 1, and the mechanical properties at 300°C are shown in Table 2. The mechanical properties of the titanium alloy rod prepared in Example 1 are shown in Table Figure 1 The mechanical properties of the titanium alloy rod obtained in Example 2 are shown in Figure 2 The mechanical properties of the titanium alloy rod obtained in Example 3 are shown in Figure 3 .from Figure 1-2It can be seen that the material has formed an obvious {0001} / / rolling direction texture feature. The texture strength of the rod of Example 1 is 5.21, the structural strength of the rod of Example 2 is 7.30, and the structural strength of the rod of Example 3 is 7.87. This texture feature can ensure that the material has a better elastic modulus when bearing load.

[0085] Table 1

[0086] Table 2

[0087] It can be seen from the results in Table 1 and Table 2 that the tensile strength, yield strength and elastic modulus of the embodiment are higher than those of the comparative example, indicating that the titanium alloy rod prepared by the method provided by the present invention has a higher elastic modulus and strength at room temperature and at a temperature of 300°C.

[0088] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a titanium alloy bar, characterized in that: The steps include: S1. Mixing metal raw materials and smelting them to obtain a titanium alloy ingot having an aluminum content of 6.7-7.1wt% and an oxygen content of 0.12-0.15wt%; the metal raw materials contain titanium and aluminum; S2. performing at least three upsetting and at least one rolling on the titanium alloy ingot.

2. The preparation method according to claim 1, characterized in that: In the step S1, the metal raw material also contains zirconium, molybdenum and vanadium.

3. The preparation method according to claim 2, characterized in that: In the titanium alloy ingot, the zirconium content is 2-2.5wt%, the molybdenum content is 1.5-2wt%, the vanadium content is 2-2.5wt%, and the balance is titanium.

4. The preparation method according to any one of claims 1 to 3, characterized in that In the titanium alloy ingot, the mass ratio of the aluminum to the oxygen is 1:0.016-0.

023.

5. The preparation method according to any one of claims 1 to 3, characterized in that: The smelting conditions at least include: a smelting current of 12-32KA, a smelting voltage of 28-43V, an arc stabilization current of 10-30A, and a commutation frequency of 10-20 seconds / time.

6. The preparation method according to any one of claims 1 to 3, characterized in that: The upsetting includes a first upsetting, a second upsetting and a third upsetting; The first upsetting process includes diagonal upsetting followed by elongation, and the conditions of the first upsetting include at least: a temperature of 1000-1200°C; The second upsetting is roughening, and the conditions of the second upsetting include at least: the temperature is T β -70 to T β -50℃; The third upsetting process includes upsetting and then lengthening, and the conditions of the third upsetting include at least: the temperature is T β -70 to T β -50℃; Among them, T β is the phase transition temperature of the titanium alloy ingot.

7. The preparation method according to claim 6, characterized in that: In the first upsetting and drawing, the diagonal drawing is performed 2-3 times, and the single deformation is 19-36%; and / or The conditions of the second upsetting also include: an upsetting ratio of 2.5-3.5; and / or The third upsetting is performed 2-4 times, and the single deformation is 30-50%.

8. The preparation method according to claim 7, characterized in that: The method further comprises: after the second upsetting, heating to T β +20 to T β After +50℃, keep warm for 120-240min.

9. The preparation method according to any one of claims 1 to 3, characterized in that: The rolling conditions at least include: a temperature of T β -90 to T β -50℃, the total deformation of the rolling is 50-75%.

10. The titanium alloy rod prepared according to the preparation method according to any one of claims 1 to 9.

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