Ti2AlNb alloy rods, their preparation methods and applications

Abstract

The application relates to the technical field of Ti2AlNb alloy processing, in particular to a Ti2AlNb alloy rod and a preparation method and application thereof. The preparation method of the Ti2AlNb alloy rod comprises the following steps: performing upsetting and drawing cycles on Ti2AlNb alloy ingots at 1050-1170 DEG C, 1010-1040 DEG C and 920-950 DEG C respectively; the number of the upsetting and drawing cycles at each temperature range is at least 3 times; and the deformation amount in the upsetting and drawing cycles is 25%-60%. The preparation method reduces the temperature points of rod forging, the upsetting and drawing forging needs 3 times of furnace loading, through the mode of multiple times of furnace re-melting of the same temperature hot material, the forging process is effectively shortened under the condition of guaranteeing that the quality of the rod is not reduced, the rod yield is increased to more than 75%, and meanwhile, the flaw detection level is obviously improved, the flaw detection level of the Ti2AlNb alloy rod with a diameter of 400 mm is increased from Phi 3.2 mm-6dB to Phi 2.0 mm-6dB.

Description

Technical Field

[0001] This invention relates to the field of Ti2AlNb alloy processing technology, and in particular to a Ti2AlNb alloy rod, its preparation method, and its application. Background Technology

[0002] Ti2AlNb alloys belong to a new generation of intermetallic compounds. They have high room temperature plasticity, high temperature strength and oxidation resistance. They can be used for a long time in the range of 700 to 800℃, and the short-term operating temperature can be higher than 1100℃, thus attracting widespread attention.

[0003] With the rapid development of the aerospace industry, Ti2AlNb alloys are being used in large-scale integral casing components, thus requiring an increase in the size of Ti2AlNb-based alloy bars to approximately 400mm. However, for Ti2AlNb alloys, when the bar size is enlarged to Φ400mm, there are issues with coarse core microstructure. Ultrasonic testing also reveals non-uniformity along the length of the bar, with ultrasonic clutter levels at both ends at Φ3.2mm-6dB, while in some areas of the middle section, it only reaches Φ3.2mm-2dB. Both strength and plasticity decrease significantly, and there are large performance differences between different parts, with the core's room temperature plasticity being significantly lower than the standard requirements.

[0004] In order to solve the above problems, the existing technology involves three-dimensional reversing forging twice at multiple temperature points, and a total of at least eight furnace loadings are required in the upsetting and drawing forging process. This results in problems such as long process flow, serious heat loss, and low bar yield (below 65%).

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] One objective of this invention is to provide a method for preparing Ti2AlNb alloy rods, thereby solving the technical problems of long processing flow and low yield in the prior art.

[0007] Another objective of this invention is to provide Ti2AlNb alloy rods with an equiaxed α / O volume fraction of 40% to 50% and a flaw detection level of Φ2.0mm-6dB.

[0008] Another object of the present invention is to provide the application of Ti2AlNb alloy rods in the preparation of integral casing components.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] The preparation method of Ti2AlNb alloy rods includes the following steps:

[0011] Ti2AlNb alloy ingots were subjected to upsetting and drawing cycles at 1050–1170℃, 1010–1040℃, and 920–950℃, respectively.

[0012] The number of upsetting cycles in each temperature range shall be at least 3;

[0013] During the upsetting and drawing cycle, the deformation is 25% to 60%.

[0014] In a specific embodiment of the present invention, the amount of deformation gradually increases during the upsetting and drawing cycle within each temperature range.

[0015] In a specific embodiment of the present invention, the preparation method includes the following steps:

[0016] (a) The Ti2AlNb alloy ingot is subjected to at least 3 upsetting and drawing cycles at 1050-1170℃, and then cooled and repaired.

[0017] (b) The billet obtained in step (a) is subjected to at least 3 upsetting and drawing cycles at 1010–1040°C, and then cooled and repaired.

[0018] (c) The billet obtained in step (b) is subjected to at least three upsetting and drawing cycles at 920–950°C, and then cooled and repaired.

[0019] In a specific embodiment of the present invention, in step (a), the deformation amount during the upsetting and drawing cycle is 30% to 60%.

[0020] In a specific embodiment of the present invention, in step (a), the upsetting and drawing cycle is performed three times. Further, in step (a), in the upsetting and drawing cycle, the deformation amount D1 in the first cycle is 30%–40%, the deformation amount D2 in the second cycle is 40%–50%, and the deformation amount D3 in the third cycle is 50%–60%; and D1 < D2 < D3.

[0021] In a specific embodiment of the present invention, in step (b), the deformation amount during the upsetting and drawing cycle is 30% to 60%.

[0022] In a specific embodiment of the present invention, in step (b), the upsetting and drawing cycle is performed three times. Further, in step (b), the deformation amount D1' in the first upsetting and drawing cycle is 30%–40%, the deformation amount D2' in the second cycle is 40%–50%, and the deformation amount D3' in the third cycle is 50%–60%; and D1' < D2' < D3'.

[0023] In a specific embodiment of the present invention, in step (c), the deformation amount during the upsetting and drawing cycle is 25% to 55%.

[0024] In a specific embodiment of the present invention, in step (c), the upsetting and drawing cycle is performed three times. Further, in step (c), in the upsetting and drawing cycle, the deformation amount D1” in the first cycle is 25% to 35%, the deformation amount D2” in the second cycle is 35% to 45%, and the deformation amount D3” in the third cycle is 45% to 55%; and D1” < D2” < D3”.

[0025] In a specific embodiment of the present invention, one upsetting and drawing cycle includes: performing an upsetting operation along a first direction at an upsetting and drawing temperature to obtain an intermediate billet; and then performing a drawing operation along the first direction on the intermediate billet. After completing one upsetting and drawing cycle, the billet size is restored to its original size.

[0026] In practice, after completing one upsetting and drawing cycle, the furnace is returned to the upsetting and drawing temperature for reheating before continuing with subsequent operations.

[0027] In a specific embodiment of the present invention, the first direction is the length direction of the Ti2AlNb alloy.

[0028] The present invention also provides Ti2AlNb alloy rods obtained by any of the above-described methods for preparing Ti2AlNb alloy rods.

[0029] In a specific embodiment of the present invention, the equiaxed α / O volume fraction in the Ti2AlNb alloy rod is 40% to 50%.

[0030] In a specific embodiment of the present invention, the ultrasonic flaw detection results of the ends and middle section of the Ti2AlNb alloy rod meet the requirements of Φ2.0mm-6dB.

[0031] The present invention also provides the application of any of the above-described Ti2AlNb alloy rods in the preparation of integral casing components.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) The method for preparing Ti2AlNb alloy bars of the present invention reduces the temperature points of bar forging. The upsetting and drawing forging requires a total of 3 furnace loading times. By repeatedly reheating the hot material at the same temperature, the forging process is effectively shortened while ensuring that the quality of the bars is not reduced. The yield of bars is increased to more than 75%, and the cost of Ti2AlNb alloy bars is effectively reduced.

[0034] (2) The method for preparing Ti2AlNb alloy rods of the present invention involves at least three upsetting and drawing operations at each temperature point, with the upsetting deformation increasing progressively. The resulting equiaxed α / O volume fraction is between 40% and 50%, significantly improving the flaw detection level from Φ3.2mm-6dB to Φ2.0mm-6dB.

[0035] (3) Based on shortening the process flow and reducing costs, this invention ensures or even improves the microstructure uniformity and mechanical properties of Ti2AlNb alloy rods, which can meet the material performance requirements of large-scale integral casing components. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 The images show high-magnification microstructures of the Ti2AlNb alloy rods prepared in Example 1 of this invention; where (a), (b), and (c) are high-magnification microstructures of the edge, 1 / 2R section, and core of the rod, respectively, with a magnification of 500x.

[0038] Figure 2 The images show high-magnification microstructures of the Ti2AlNb alloy rods prepared in Comparative Example 1 of the present invention; where (a), (b), and (c) are high-magnification microstructures of the edge, 1 / 2R section, and core of the rod, respectively, with a magnification of 500x. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0040] The preparation method of Ti2AlNb alloy rods includes the following steps:

[0041] Ti2AlNb alloy ingots were subjected to upsetting and drawing cycles at 1050–1170℃, 1010–1040℃, and 920–950℃, respectively.

[0042] The number of upsetting cycles in each temperature range shall be at least 3;

[0043] During the upsetting and drawing cycle, the deformation is 25% to 60%.

[0044] The method for preparing Ti2AlNb alloy bars of the present invention reduces the temperature points for bar forging, and the total number of furnace loading times for upsetting and drawing forging is reduced to 3. By repeatedly reheating the hot material at the same temperature, the forging process is effectively shortened while ensuring that the quality of the bars is not reduced, and the yield of bars is increased to more than 75%, thereby effectively reducing the cost of Ti2AlNb alloy bars.

[0045] In the preparation method of this invention, the temperature corresponding to the third set of upsetting and drawing cycles is 920-950℃, which is near-β or β forging. By reducing the final forging temperature, the temperature points of intermediate forging during the forging process are reduced. At the same time, it ensures a more uniform microstructure and improves the flaw detection level from Φ3.2mm-6dB to Φ2.0mm-6dB, while still meeting the performance requirements of the bar stock standard. If the temperature of the third set of upsetting and drawing cycles is too high, it will result in a low volume fraction of isometric α / O phase in the microstructure (e.g., below 20%), and poor microstructure uniformity.

[0046] In different embodiments, the deformation amount in the upsetting and drawing cycle can be exemplarily 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc.

[0047] In a specific embodiment of the present invention, the amount of deformation gradually increases during the upsetting and drawing cycle within each temperature range.

[0048] The method for preparing Ti2AlNb alloy bars of the present invention involves at least three upsetting and drawing processes at each temperature point, with the upsetting deformation increasing progressively. This ensures that the corresponding forging effect is achieved with fewer forging passes, resulting in sufficient core deformation, high equiaxedness, and uniform microstructure.

[0049] Furthermore, this invention lowers the forging temperature, increases the amount of precipitated phases, and ensures high-magnification uniformity of the microstructure. As upsetting and drawing proceed, the degree of equiaxation of the precipitated phases increases, plasticity improves, and the deformation amount gradually increases, achieving better forging results; while ensuring a reduction in the number of forging passes and sufficient deformation of the bar core.

[0050] In a specific embodiment of the present invention, the preparation method includes the following steps:

[0051] (a) The Ti2AlNb alloy ingot is subjected to at least 3 upsetting and drawing cycles at 1050-1170℃, and then cooled and repaired.

[0052] (b) The billet obtained in step (a) is subjected to at least 3 upsetting and drawing cycles at 1010–1040°C, and then cooled and repaired.

[0053] (c) The billet obtained in step (b) is subjected to at least three upsetting and drawing cycles at 920–950°C, and then cooled and repaired.

[0054] In different embodiments, in step (a), the forging temperature can be, for example, 1050°C, 1055°C, 1060°C, 1065°C, 1070°C, etc.; in step (b), the forging temperature can be, for example, 1010°C, 1015°C, 1020°C, 1025°C, 1030°C, 1035°C, 1040°C, etc.; in step (c), the forging temperature can be, for example, 920°C, 925°C, 930°C, 935°C, 940°C, 945°C, 950°C, etc.

[0055] In a specific embodiment of the present invention, the cooling method in the cooling repair is air cooling, and the repair includes: 100% grinding and cleaning of the surface of the billet.

[0056] In a specific embodiment of the present invention, in step (a), the deformation amount during the upsetting and drawing cycle is 30% to 60%.

[0057] In different implementations, in step (a), the deformation amount during the upsetting cycle can be, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc.

[0058] In a specific embodiment of the present invention, in step (a), the upsetting and drawing cycle is performed three times. Further, in step (a), in the upsetting and drawing cycle, the deformation amount D1 in the first cycle is 30%–40%, the deformation amount D2 in the second cycle is 40%–50%, and the deformation amount D3 in the third cycle is 50%–60%; and D1 < D2 < D3.

[0059] In different implementations, in step (a), the first deformation amount D1 can be exemplarily 30%, 32%, 34%, 35%, 36%, 38%, 40%, etc.; the second deformation amount D2 can be exemplarily 40%, 42%, 44%, 45%, 46%, 48%, 50%, etc.; and the third deformation amount D3 can be exemplarily 50%, 52%, 54%, 55%, 56%, 58%, 60%, etc.

[0060] In a specific embodiment of the present invention, in step (b), the deformation amount during the upsetting and drawing cycle is 30% to 60%.

[0061] In different implementations, in step (b), the deformation amount during the upsetting cycle can be, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc.

[0062] In a specific embodiment of the present invention, in step (b), the upsetting and drawing cycle is performed three times. Further, in step (b), the deformation amount D1' in the first upsetting and drawing cycle is 30%–40%, the deformation amount D2' in the second cycle is 40%–50%, and the deformation amount D3' in the third cycle is 50%–60%; and D1' < D2' < D3'.

[0063] In different implementations, in step (b), the first deformation amount D1' can be exemplarily 30%, 32%, 34%, 35%, 36%, 38%, 40%, etc.; the second deformation amount D2' can be exemplarily 40%, 42%, 44%, 45%, 46%, 48%, 50%, etc.; and the third deformation amount D3' can be exemplarily 50%, 52%, 54%, 55%, 56%, 58%, 60%, etc.

[0064] In a specific embodiment of the present invention, in step (c), the deformation amount during the upsetting and drawing cycle is 25% to 55%.

[0065] In different implementations, in step (c), the deformation amount during the upsetting and drawing cycle can be exemplarily 25%, 30%, 35%, 40%, 45%, 50%, 55%, etc.

[0066] In a specific embodiment of the present invention, in step (c), the upsetting and drawing cycle is performed three times. Further, in step (c), in the upsetting and drawing cycle, the deformation amount D1” in the first cycle is 25% to 35%, the deformation amount D2” in the second cycle is 35% to 45%, and the deformation amount D3” in the third cycle is 45% to 55%; and D1” < D2” < D3”.

[0067] In different implementations, in step (c), the first deformation amount D1” can be exemplarily 25%, 26%, 28%, 30%, 32%, 34%, 35%, etc.; the second deformation amount D2” can be exemplarily 35%, 36%, 38%, 40%, 42%, 44%, 45%, etc.; and the third deformation amount D3” can be exemplarily 45%, 46%, 48%, 50%, 52%, 54%, 55%, etc.

[0068] In a specific embodiment of the present invention, one upsetting and drawing cycle includes: first shaping the billet to d×d×L at the upsetting and drawing temperature, then performing an upsetting operation along a first direction to obtain an intermediate billet; and then performing a drawing operation on the intermediate billet along the first direction. After completing one upsetting and drawing cycle, the billet size is restored to its original size.

[0069] For example, if the ingot's forming dimensions are d×d×L, an upsetting operation is performed along the L direction at the upsetting temperature to obtain an intermediate billet with dimensions d'×d'×L'. Then, the intermediate billet is drawn along the L direction to restore the billet's dimensions to d×d×L. This completes one upsetting and drawing cycle.

[0070] In practice, after completing one upsetting and drawing cycle, the furnace is returned to the upsetting and drawing temperature for reheating before continuing with subsequent operations.

[0071] In actual operation, the billet insulation coefficient is calculated as 0.8 to 1.0 min / mm, and then the corresponding upsetting and drawing cycle operation is carried out.

[0072] In a specific embodiment of the present invention, the first direction is the length direction of the Ti2AlNb alloy.

[0073] In a specific embodiment of the present invention, the method further includes: rolling the treated bar blank into a round shape at 920-950°C.

[0074] In a specific embodiment of the present invention, the Ti2AlNb alloy ingot can be prepared by conventional smelting methods; for example, it can be prepared by a method of one vacuum consumable melting, a second vacuum solidification melting, and a third vacuum consumable melting.

[0075] The present invention also provides Ti2AlNb alloy rods obtained by any of the above-described methods for preparing Ti2AlNb alloy rods.

[0076] In a specific embodiment of the present invention, the equiaxed α / O volume fraction in the Ti2AlNb alloy rod is 40% to 50%.

[0077] In different embodiments, the equiaxed α / O volume fraction in the Ti2AlNb alloy rod can be, for example, 40%, 42%, 44%, 45%, 46%, 48%, 50%, etc.

[0078] In a specific embodiment of the present invention, the ultrasonic flaw detection results of the ends and middle section of the Ti2AlNb alloy rod meet the requirements of Φ2.0mm-6dB.

[0079] The present invention also provides the application of any of the above-described Ti2AlNb alloy rods in the preparation of integral casing components.

[0080] The alloy composition of the Ti2AlNb rod used in the specific embodiments of the present invention is illustrated by taking Ti-22Al-25Nb as an example, but it is not limited to this, and other Ti2AlNb-based alloys are also acceptable.

[0081] Example 1

[0082] This embodiment provides a method for preparing Ti2AlNb alloy rods, including the following steps:

[0083] (1) Heat the Ti2AlNb ingot with a shape of 400mm×400mm×840mm to 1160℃ and hold for 320min. Place it on a forging machine and upset it along the length of the ingot to obtain an intermediate billet with a shape of 495mm×495mm×550mm and a deformation of 35%. Then draw the intermediate billet to obtain a bar billet with a shape of 400mm×400mm×840mm.

[0084] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 540mm×540mm×460mm, with a deformation of 45%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0085] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 595mm×595mm×380mm, with a deformation of 55%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0086] Cooling and repair: After completing three upsetting and drawing cycles at 1160℃, air cool, and then grind 100% of the surface of the billet to remove damage.

[0087] (2) Heat the billet obtained in step (1) to 1025℃ and hold for 320 min. Place it on a forging equipment and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 495mm×495mm×550mm and a deformation of 35%. Then draw the intermediate billet to obtain a billet with dimensions of 400mm×400mm×840mm.

[0088] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 540mm×540mm×460mm, with a deformation of 45%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0089] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 595mm×595mm×380mm, with a deformation of 55%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0090] Cooling and repairing: Complete three upsetting and drawing cycles at 1025℃, air cool, and then grind 100% of the surface of the billet to remove damage.

[0091] (3) Heat the billet obtained in step (2) to 935℃ and hold for 320 minutes. Place it on a forging equipment and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 480mm×480mm×585mm and a deformation of 30%. Then draw the intermediate billet to obtain a billet with dimensions of 400mm×400mm×840mm.

[0092] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 515mm×515mm×505mm, with a deformation of 40%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0093] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 565mm×565mm×420mm, with a deformation of 50%; then the intermediate billet is drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0094] Cooling and repairing; complete three upsetting and drawing cycles at 935℃ to grind and clean 100% of the surface of the billet.

[0095] (4) Heat the Ti2AlNb billet with dimensions of 400mm×400mm×840mm to 935℃ and hold for 320min. Place it on a forging machine and upset it along the length of the billet to obtain an octagonal billet with dimensions of 440mm×440mm×700mm. Then roll the intermediate billet to obtain a billet with dimensions of φ415mm×1000mm.

[0096] Cooling and repair; complete 935℃ rounding forming, and grind 100% of the surface of the billet to remove damage. Obtain Ti2AlNb alloy rod.

[0097] Example 2

[0098] This embodiment provides a method for preparing Ti2AlNb alloy rods, including the following steps:

[0099] (1) Heat a Ti2AlNb ingot with dimensions of 400mm×400mm×840mm to 1150℃ and hold for 320min. Place it on a forging machine and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 480mm×480mm×585mm, with a deformation of 30%. Then draw the intermediate billet to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0100] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 515mm×515mm×505mm, with a deformation of 40%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0101] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 565mm×565mm×420mm, with a deformation of 50%; then the intermediate billet is drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0102] Cooling and repairing: Complete three upsetting and drawing cycles at 1150℃, air cool, and then grind 100% of the surface of the billet to remove damage.

[0103] (2) Heat the billet obtained in step (1) to 1010℃ and hold for 320 min. Place it on a forging equipment and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 480mm×480mm×585mm and a deformation of 30%. Then draw the intermediate billet to obtain a billet with dimensions of 400mm×400mm×840mm.

[0104] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 515mm×515mm×505mm, with a deformation of 40%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0105] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 565mm×565mm×420mm, with a deformation of 50%; then the intermediate billet is drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0106] Cooling and repairing: Complete three upsetting and drawing cycles at 1010℃, air cool, and then grind 100% of the surface of the billet to remove damage.

[0107] (3) Heat the billet obtained in step (2) to 920℃ and hold for 320 minutes. Place it on a forging equipment and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 460mm×460mm×630mm and a deformation of 25%. Then draw the intermediate billet to obtain a billet with dimensions of 400mm×400mm×840mm.

[0108] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 495mm×495mm×550mm, with a deformation of 35%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0109] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 540mm×540mm×460mm, with a deformation of 45%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0110] Cooling and repairing; complete three upsetting and drawing cycles at 920℃, air cool, and then grind 100% of the surface of the billet to remove damage.

[0111] (4) Heat the Ti2AlNb billet with dimensions of 400mm×400mm×840mm to 935℃ and hold for 320min. Place it on a forging machine and upset it along the length of the billet to obtain an octagonal billet with dimensions of 440mm×440mm×700mm. Then roll the intermediate billet to obtain a billet with dimensions of φ415mm×1000mm.

[0112] Cooling and repair; complete 920℃ rounding forming, and grind 100% of the surface of the billet to remove damage. Obtain Ti2AlNb alloy rod.

[0113] Example 3

[0114] This embodiment provides a method for preparing Ti2AlNb alloy rods, including the following steps:

[0115] (1) Heat a Ti2AlNb ingot with dimensions of 400mm×400mm×840mm to 1170℃ and hold for 320min. Place it on a forging machine and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 515mm×515mm×505mm, with a deformation of 40%. Then draw the intermediate billet to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0116] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 565mm×565mm×420mm, with a deformation of 50%; then the intermediate billet is drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0117] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 630mm×630mm×340mm, with a deformation of 60%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0118] Cooling and repairing: Complete three upsetting and drawing cycles at 1170℃, air cool, and then grind 100% of the surface of the billet to remove damage.

[0119] (2) Heat the billet obtained in step (1) to 1040℃ and hold for 320 minutes. Place it on a forging equipment and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 515mm×515mm×505mm and a deformation of 40%. Then draw the intermediate billet to obtain a billet with dimensions of 400mm×400mm×840mm.

[0120] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 565mm×565mm×420mm, with a deformation of 50%; then the intermediate billet is drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0121] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 630mm×630mm×340mm, with a deformation of 60%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0122] Cooling and repairing: Complete three upsetting and drawing cycles at 1040℃, air cool, and then grind 100% of the surface of the billet to remove damage.

[0123] (3) Heat the billet obtained in step (2) to 950℃ and hold for 320 minutes. Place it on a forging equipment and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 495mm×495mm×550mm and a deformation of 35%. Then draw the intermediate billet to obtain a billet with dimensions of 400mm×400mm×840mm.

[0124] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 540mm×540mm×460mm, with a deformation of 45%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0125] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 595mm×595mm×380mm, with a deformation of 55%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0126] Cooling and repairing; complete three upsetting and drawing cycles at 950℃, air cool, and then grind the billet 100% to remove damage.

[0127] (4) Heat the Ti2AlNb billet with dimensions of 400mm×400mm×840mm to 950℃ and hold for 320min. Place it on a forging machine and upset it along the length of the billet to obtain an octagonal billet with dimensions of 440mm×440mm×700mm. Then roll the intermediate billet to obtain a billet with dimensions of φ415mm×1000mm.

[0128] Cooling and repair; complete 950℃ rounding forming, and grind 100% of the surface of the billet to remove damage. Obtain Ti2AlNb alloy rods.

[0129] Example 4

[0130] This embodiment refers to the preparation method of Example 1, and includes the following steps:

[0131] (1) Heat a Ti2AlNb ingot with dimensions of 400mm×400mm×840mm to 1160℃ and hold for 320min. Place it on a forging machine and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 540mm×540mm×460mm and a deformation of 45%. Then draw the intermediate billet to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0132] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 540mm×540mm×460mm, with a deformation of 45%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0133] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 540mm×540mm×460mm, with a deformation of 45%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0134] Cooling and repairing; complete three upsetting and drawing cycles at 1160℃, cool, and then grind the billet 100% to remove damage.

[0135] (2) Heat the billet obtained in step (1) to 1025℃ and hold for 320 minutes. Place it on a forging equipment and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 540mm×540mm×460mm and a deformation of 45%. Then draw the intermediate billet to obtain a billet with dimensions of 400mm×400mm×840mm.

[0136] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 540mm×540mm×460mm, with a deformation of 45%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0137] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 540mm×540mm×460mm, with a deformation of 45%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0138] Cooling and repair: Complete three upsetting and drawing cycles at 1025℃, air cool, and then grind the billet to remove 100% of the damage.

[0139] (3) Heat the billet obtained in step (2) to 935℃ and hold for 320 minutes. Place it on a forging equipment and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 515mm×515mm×505mm and a deformation of 40%. Then draw the intermediate billet to obtain a billet with dimensions of 400mm×400mm×840mm.

[0140] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 515mm×515mm×505mm, with a deformation of 40%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0141] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 515mm×515mm×505mm, with a deformation of 40%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0142] Cooling and repair: After completing three upsetting and drawing cycles at 935℃, air cool the billet and then grind it 100% to remove the defects.

[0143] (4) Heat the Ti2AlNb billet with dimensions of 400mm×400mm×840mm to 935℃ and hold for 320min. Place it on a forging machine and upset it along the length of the billet to obtain an octagonal billet with dimensions of 440mm×440mm×700mm. Then roll the intermediate billet to obtain a billet with dimensions of φ415mm×1000mm.

[0144] Cooling and repair; complete 935℃ rounding to obtain Ti2AlNb alloy rods.

[0145] Example 5

[0146] This embodiment provides a method for preparing Ti2AlNb alloy rods, including the following steps:

[0147] (1) Heat a Ti2AlNb ingot with dimensions of 400mm×400mm×840mm to 1160℃ and hold for 320min. Place it on a forging machine and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 495mm×495mm×550mm, with a deformation of 35%. Then draw the intermediate billet to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0148] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 515mm×515mm×505mm, with a deformation of 40%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0149] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 540mm×540mm×460mm, with a deformation of 45%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0150] Cooling and repairing; complete three upsetting and drawing cycles at 1160℃, air cool, and then grind the bar 100% to remove damage.

[0151] (2) Heat the billet obtained in step (1) to 1025℃ and hold for 320 min. Place it on a forging equipment and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 495mm×495mm×550mm and a deformation of 35%. Then draw the intermediate billet to obtain a billet with dimensions of 400mm×400mm×840mm.

[0152] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 515mm×515mm×505mm, with a deformation of 40%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0153] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 540mm×540mm×460mm, with a deformation of 45%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0154] Cooling and repairing; complete three upsetting and drawing cycles at 1025℃, air cool, and then grind 100% of the surface of the billet to remove damage.

[0155] (3) Heat the billet obtained in step (2) to 935℃ and hold for 320 minutes. Place it on a forging equipment and upset it along the length of the ingot to obtain an intermediate billet with dimensions of 480mm×480mm×585mm and a deformation of 30%. Then draw the intermediate billet to obtain a billet with dimensions of 400mm×400mm×840mm.

[0156] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 495mm×495mm×550mm, with a deformation of 35%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0157] The hot material is returned to the furnace, and then the 400mm×400mm×840mm bar billet is upset to obtain an intermediate billet with dimensions of 515mm×515mm×505mm, with a deformation of 40%; the intermediate billet is then drawn to obtain a bar billet with dimensions of 400mm×400mm×840mm.

[0158] Cooling and repairing; complete three upsetting and drawing cycles at 935℃, air cool, and then grind 100% of the surface of the billet to remove damage.

[0159] (4) Heat the Ti2AlNb billet with dimensions of 400mm×400mm×840mm to 935℃ and hold for 320min. Place it on a forging machine and upset it along the length of the billet to obtain an octagonal billet with dimensions of 440mm×440mm×700mm. Then roll the intermediate billet to obtain a billet with dimensions of φ415mm×1000mm. Complete the 935℃ rolling forming to obtain Ti2AlNb alloy rod.

[0160] Comparative Example 1

[0161] Comparative Example 1 provides a method for preparing Ti2AlNb alloy rods, referring to Example 1 in CN112275984A.

[0162] Comparative Example 2

[0163] Comparative Example 2 provides a method for preparing Ti2AlNb alloy rods, referencing Comparative Example 1 in CN112275984A.

[0164] Experimental Example 1

[0165] The Ti2AlNb alloy rods prepared in Example 1 and Comparative Example 1 were examined by scanning electron microscopy, and the high-magnification microstructures obtained are shown below. Figure 1 and Figure 2 As shown.

[0166] The specific test results for the Ti2AlNb alloy rods obtained in each embodiment and comparative example, including the grain size test standard (GBT6494-2017) and the volume fraction of equiaxed α / O phase (test standard: image pro plus), are shown in Table 1.

[0167] Table 1. Test results of the middle section of different Ti2AlNb alloy bars.

[0168]

[0169] from Figure 1 As can be seen from the above, the Ti2AlNb alloy rod prepared in Example 1 of this invention has a high degree of equiaxation in the core, and the edges, 1 / 2R portion, and core all have a high degree of equiaxation and good uniformity. Figure 2 As can be seen from the above, the Ti2AlNb alloy rod prepared in Comparative Example 1 has a relatively poor degree of equiaxation, and the volume fraction of the second phase in the core and the edge is significantly different.

[0170] Experiment Example 2

[0171] Ultrasonic testing was performed on the Ti2AlNb alloy rods prepared in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 2.

[0172] Table 2 Flaw detection results of different Ti2AlNb alloy bars

[0173] serial number Ultrasonic flaw detection results Example 1 Φ2.0mm-6dB Example 2 Φ2.0mm-6dB Example 3 Φ2.0mm-6dB Example 4 Φ2.0mm-6dB Example 5 Φ2.0mm-6dB Comparative Example 1 Φ3.2mm-6dB Comparative Example 2 Φ3.2mm-2dB

[0174] The mechanical properties of the Ti2AlNb alloy rods prepared in Example 1 and Comparative Example 1 were further tested. The test results are shown in Tables 3 and 4.

[0175] Table 3 Performance test results of Ti2AlNb alloy rods in Example 1

[0176]

[0177] Table 4 Performance test results of Ti2AlNb alloy rods in Comparative Example 1

[0178]

[0179]

[0180] Furthermore, the yield of the Ti2AlNb alloy rods prepared in Examples 1-5 was calculated, as shown in Table 5.

[0181] Table 5. Yield of Ti2AlNb alloy rods in Examples 1-5

[0182] serial number Yield / % Example 1 76％ Example 2 70％ Example 3 79％ Example 4 75％ Example 5 77％

[0183] Based on the above tests, it can be seen that the preparation process in Example 1 can better balance the microstructure and properties of Ti2AlNb alloy rods with a high yield.

[0184] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing Ti2AlNb alloy rods, characterized in that, Includes the following steps: (a) The Ti2AlNb alloy ingot was subjected to three upsetting and drawing cycles at 1050~1170℃, and then cooled and repaired. (b) The billet obtained in step (a) is subjected to three upsetting and drawing cycles at 1010~1040℃, and then cooled and repaired. (c) The billet obtained in step (b) is subjected to three upsetting and drawing cycles at 920~945℃, and then cooled and repaired. In step (a), during the upsetting and drawing cycle, the deformation amount D1 in the first cycle is 30%~40%, the deformation amount D2 in the second cycle is 40%~50%, and the deformation amount D3 in the third cycle is 50%~60%; and D1 < D2 < D3. In step (b), during the upsetting and drawing cycle, the deformation amount D1' in the first cycle is 30%~40%, the deformation amount D2' in the second cycle is 40%~50%, and the deformation amount D3' in the third cycle is 50%~60%; and D1' < D2' < D3'. In step (c), during the upsetting and drawing cycle, the deformation amount D1'' in the first cycle is 25%~35%, the deformation amount D2'' in the second cycle is 35%~45%, and the deformation amount D3'' in the third cycle is 45%~55%; and D1'' < D2'' < D3''. The equiaxed α / O volume fraction of the Ti2AlNb alloy rod is 40%~50%.

2. The method for preparing Ti2AlNb alloy rods according to claim 1, characterized in that, One upsetting and drawing cycle includes: performing an upsetting operation along a first direction at an upsetting and drawing temperature to obtain an intermediate billet; and then performing a drawing operation on the intermediate billet along the first direction.

3. The method for preparing Ti2AlNb alloy rods according to claim 2, characterized in that, The first direction is the length direction of the Ti2AlNb alloy.

4. Ti2AlNb alloy rods prepared by the method of any one of claims 1 to 3.

5. The Ti2AlNb alloy rod according to claim 4, characterized in that... The ultrasonic flaw detection results of the ends and middle sections of the Ti2AlNb alloy rod meet the requirements of Φ2.0mm-6dB.

6. The application of the Ti2AlNb alloy rod as described in claim 4 or 5 in the preparation of large-size integral casing components.

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