Method for improving hardenability of high-temperature titanium alloy

Abstract

This invention provides a method for improving the hardenability of high-temperature titanium alloys, comprising the following steps: S1: Introducing fast-diffusion components through melting during the high-temperature titanium alloy forming process to obtain an ingot; S2: Pre-treating the ingot obtained in S1; S3: Forging the pre-treated ingot in S2; S4: Performing solution treatment and aging treatment on the forged high-temperature titanium alloy in S3; S5: Processing the high-temperature titanium alloy after heat treatment in S4 into profiles of the required specifications. The method for improving the hardenability of high-temperature titanium alloys provided by this invention introduces Fe and Ni fast-diffusion components, making the titanium alloy ingot more uniform during the melting process; the ingot pre-treatment effectively eliminates the initiation source of surface cracks in the ingot; ultrasonic testing can detect the internal quality of the ingot; after β single-phase region billeting, multi-fire forging in the two-phase region, and subsequent heat treatment, the microstructure of the high-temperature titanium alloy consists of primary equiaxed α particles, a β matrix, and secondary acicular α phases, exhibiting excellent comprehensive performance.

Description

Technical Field

[0001] This invention relates to the field of high-strength titanium alloy preparation technology, and in particular to a method for improving the hardenability of high-temperature titanium alloys. Background Technology

[0002] Titanium alloys, with their significant specific strength, excellent corrosion resistance, and good high-temperature stability, have become key materials in many industrial fields, including aerospace, automotive manufacturing, shipbuilding, and energy and chemical engineering. Especially in aerospace, with the continuous advancement of manufacturing processes for large, monolithic components, higher performance standards have been set for titanium alloys: they must not only maintain excellent high-temperature performance but also possess a highly uniform and stable microstructure.

[0003] To meet the increasing demands on titanium alloy performance in equipment such as aero-engines, various strengthening processes are employed to modify the material. While these methods effectively improve intrinsic properties such as strength, they also introduce numerous problems, including decreased formability (specifically, a narrowing of the hot working range and increased susceptibility to cracking during cold deformation), exacerbated uneven distribution of trace elements, and reduced bonding performance. In the manufacture of large titanium alloy components, the difference in microstructure between the core and surface due to insufficient through-hardening is particularly prominent. Under conventional heat treatment conditions, the cooling rate of the core during quenching of large components is significantly lower than that of the surface, making it difficult to effectively suppress adverse transformations of high-temperature phases during cooling. This results in a coarse and non-uniform microstructure in the core region. This structural inhomogeneity significantly weakens the overall mechanical properties and service life of the component, making it difficult to meet the stringent requirements for material microstructure consistency in high-performance integrated manufacturing. Summary of the Invention

[0004] This invention provides a method for improving the hardenability of high-temperature titanium alloys, thereby solving the problems of uneven microstructure, poor hardenability, and severe segregation of trace elements in high-temperature titanium alloys in the prior art.

[0005] This invention provides a method for improving the hardenability of high-temperature titanium alloys, comprising the following steps: S1: Fast-diffusion components are introduced through melting during the high-temperature titanium alloy forming process, and an ingot is obtained; S2: Pre-process the ingot obtained in S1; S3: Forging the pre-treated ingot from S2; S4: The high-temperature titanium alloy after forging in S3 is subjected to solution treatment and aging treatment; S5: The high-temperature titanium alloy after S4 heat treatment is processed into profiles of the required specifications.

[0006] Optionally, the high-temperature titanium alloy is a titanium alloy that can serve for a long time at temperatures above 550°C, and the titanium alloy is one of Ti60, Ti65, and Ti175.

[0007] Optionally, the fast-diffusion component in S1 is one or more of Fe and Ni elements, wherein the Fe element is introduced through any form of AlFe40 alloy or TiFe40 alloy, and the Ni element is introduced through any form of AlNi50 alloy or TiNi60 alloy, and the mass of the Fe element is 0.15%-2% of the total alloy mass, and the mass of the Ni element is 0.8%-1.8% of the total alloy mass. The melting method is vacuum consumable arc melting, with no less than three melting cycles, a melting voltage of 30-35V, and a current of 10kA-15kA. When the remaining mass of the electrode block drops to 10%, 7%, and 4%, the current is gradually reduced to 70%, 50%, and 30% of the original current value. Electromagnetic stirring is performed during the melting process, with a stirring frequency of 5-15Hz and a stirring current of 500-1000A.

[0008] Optionally, the pretreatment operation in S2 is to cut off the oxide scale on the surface of the ingot to a depth of 2-5 mm, perform ultrasonic testing after cutting, and then cut off the riser.

[0009] Optionally, the forging in S3 includes a first forging, a second forging, and a third forging in sequence, and after each forging is completed and cooled to room temperature, the surface is polished to remove surface creases and microcracks.

[0010] Optionally, the first heating process is as follows: the billet is heated to 30-50°C above the β phase transformation point, the deformation method is three upsetting and three drawing, the upsetting deformation amount is 50%, the upsetting rate is 40-60mm / s, after the single deformation is completed, the billet is rotated 90° to change direction, and the end face is chamfered after the end is completed.

[0011] Optionally, the second heating process is as follows: the billet is heated to 30-50°C below the β phase transformation point, the deformation method is three upsetting and one drawing, the total deformation is 50%, the upsetting rate is 10-20 mm / s, and the end face is chamfered after the process is completed.

[0012] Optionally, the third forging process is as follows: the billet is heated to 60-80°C below the β phase transformation point, and the deformation method is one upsetting and one drawing, with a total deformation of 50% and an upsetting rate of 6-8 mm / s. After the upsetting is completed, the end face is chamfered. After this forging is completed, it is air-cooled to room temperature.

[0013] Optionally, the solution treatment process in S4 is as follows: first, solution treatment at 80-120℃ below the β phase transition point for 20-30 minutes, then heating to 20-40℃ below the β phase transition point for a second solution treatment for 1-2 hours, followed by oil quenching. The aging treatment process is as follows: after the solution treatment, aging at 500-550℃ for 2-4 hours, followed by aging at 600-650℃ for 8-16 hours, and finally air cooling to room temperature.

[0014] Optionally, in S5, after the high-temperature titanium alloy is processed into profiles of the required specifications, it is subjected to cryogenic treatment and surface shot peening treatment in sequence. The cryogenic treatment temperature is -100 to -196℃, and the time is 1-6 hours. The shot peening coverage is not less than 200%, and the shot peening intensity is 0.2-0.5 mmA.

[0015] The beneficial effects of the method for improving the hardenability of high-temperature titanium alloys provided by this invention are as follows: Introducing Fe and Ni fast-diffusion components makes the titanium alloy ingots more uniform during the smelting process; ingot pretreatment effectively eliminates the initiation source of surface cracks; ultrasonic testing can detect the internal quality of the ingot; after β-single-phase billet preparation, two-phase ingot casting, and subsequent heat treatment, the microstructure of the high-temperature titanium alloy consists of primary equiaxed α particles, a β matrix, and secondary acicular α phases, resulting in excellent overall performance. Furthermore, this invention controls the content of Fe and Ni fast-diffusion components; below the required range, the fast-diffusion components cannot function effectively, while exceeding this range will cause component segregation, reducing the material's mechanical properties and creep resistance. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the 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 based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the end-quenching experiment conducted in this invention; Figure 2 This is a comparison diagram of the end-quenching experimental results of Embodiment 1 and Comparative Example 1 of the present invention; Figure 3 This is a comparison chart of the end-quenching experimental results of Embodiment 2 and Comparative Example 2 of the present invention; Figure 4 This is a comparison chart of the end-quenching experimental results of Example 3 and Comparative Example 3 of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of the present invention.

[0019] This invention provides a method for improving the hardenability of high-temperature titanium alloys, comprising the following steps: S1: Fast-diffusion components are introduced through melting during the high-temperature titanium alloy forming process, and an ingot is obtained; S2: Pre-process the ingot obtained in S1; S3: Forging the pre-treated ingot from S2; S4: The high-temperature titanium alloy after forging in S3 is subjected to solution treatment and aging treatment; S5: The high-temperature titanium alloy after S4 heat treatment is processed into profiles of the required specifications.

[0020] The method for improving the hardenability of high-temperature titanium alloys provided by this invention Furthermore, the high-temperature titanium alloy is a titanium alloy that can serve for a long time at temperatures above 550°C, and the titanium alloy is one of Ti60, Ti65, and Ti175.

[0021] Furthermore, the fast-diffusion component in S1 is one or more of Fe and Ni elements. Fe is introduced through either AlFe40 or TiFe40 alloy, and Ni is introduced through either AlNi50 or TiNi60 alloy. The mass of Fe is 0.15%-2% of the total alloy mass, and the mass of Ni is 0.8%-1.8% of the total alloy mass. The melting method is vacuum arc melting, with at least three melting cycles. The melting voltage is 30-35V, and the current is 10kA-15kA. When the remaining mass of the electrode block decreases to 10%, 7%, and 4%, the current is gradually reduced to 70%, 50%, and 30% of its original value, respectively. Electromagnetic stirring is performed during the melting process at a frequency of 5-15Hz and a stirring current of 500-1000A.

[0022] Fe, as a strong β-phase stabilizing element, can exert multiple beneficial effects when present in trace amounts in α-type titanium alloys: lowering the β→α phase transformation temperature, expanding the β-phase region, enhancing the high-temperature plasticity of the material, and refining the micrograin size. The introduction of Ni can form fine Ni-Ti intermetallic compounds at the grain boundaries of titanium alloys, improving creep resistance and maintaining microstructural stability by pinning these grain boundaries. Furthermore, Fe and Ni, as rapidly diffusing atoms in the α-Ti lattice, can achieve diffusion coefficients up to 10 times that of titanium's self-diffusion coefficient at 600℃. 7 Up to 10 8 Introducing trace amounts of Fe or Ni into titanium alloys can effectively accelerate the atomic migration process within the alloy, thereby improving the uniformity of the microstructure and enhancing hardenability, ultimately meeting the design requirements for integral manufacturing of components.

[0023] Furthermore, the pretreatment operation in S2 involves cutting off the oxide scale on the surface of the ingot to a depth of 2-5 mm. After cutting, ultrasonic testing is performed, and then the riser is cut off.

[0024] Furthermore, the forging in S3 includes a first forging, a second forging, and a third forging in sequence. After each forging is completed and cooled to room temperature, the surface is polished to remove surface creases and microcracks.

[0025] Furthermore, the first heating process is as follows: the billet is heated to 30-50°C above the β phase transformation point, the deformation method is three upsetting and three drawing, the upsetting deformation amount is 50%, the upsetting rate is 40-60mm / s, after the single deformation is completed, it is rotated 90° to change direction, and the end face is chamfered after the end is completed.

[0026] Furthermore, the second heating process is as follows: the billet is heated to 30-50°C below the β phase transformation point, the deformation method is three upsetting and one drawing, the total deformation is 50%, the upsetting rate is 10-20mm / s, and the end face is chamfered after completion.

[0027] Furthermore, the third forging process is as follows: the billet is heated to 60-80°C below the β phase transformation point, and the deformation method is one upsetting and one drawing, with a total deformation of 50% and an upsetting rate of 6-8 mm / s. After the upsetting is completed, the end face is chamfered. After this forging is completed, it is air-cooled to room temperature.

[0028] Furthermore, the solution treatment process in S4 is as follows: first, solution treatment is carried out at 80-120℃ below the β phase transition point for 20-30 minutes, then the temperature is raised to 20-40℃ below the β phase transition point for a second solution treatment for 1-2 hours, followed by oil quenching. The aging treatment process is as follows: after the solution treatment, aging is first carried out at 500-550℃ for 2-4 hours, then at 600-650℃ for 8-16 hours, and finally air-cooled to room temperature.

[0029] Furthermore, in S5, after the high-temperature titanium alloy is processed into profiles of the required specifications, it is subjected to cryogenic treatment and surface shot peening treatment in sequence. The cryogenic treatment temperature is -100 to -196℃, and the time is 1-6 hours. The shot peening coverage is not less than 200%, and the shot peening intensity is 0.2-0.5 mmA.

[0030] Cryogenic treatment can further transform any remaining β phase in the material into the α phase, reducing the content of unstable phases and thus improving the dimensional and microstructural stability of the component during long-term use. Simultaneously, the micro-shrinkage during cryogenic treatment can homogenize and release some microscopic internal stresses, reducing stress concentration. Shot peening can induce plastic deformation in the surface material, forming a reinforced layer on the component surface to balance any harmful tensile stresses that may be generated during quenching, inhibiting the initiation and propagation of surface cracks, and improving bending fatigue and contact fatigue life.

[0031] High-temperature titanium alloys prepared by this method can be processed into various sizes such as bars, plates, and wires, making them suitable for a variety of applications.

[0032] The present invention will be further described in detail below with reference to specific embodiments.

[0033] Example 1 A method for improving the hardenability of high-temperature titanium alloys includes the following steps: S1: During the casting process of Ti60 alloy, 1% Fe element by mass is introduced in the form of AlFe40 alloy. The melting method is vacuum arc melting, with no less than three melting cycles. The melting voltage is 30V and the current is 10kA. When the remaining mass of the electrode block drops to 10%, 7%, and 4%, the current is gradually reduced to 70%, 50%, and 30% of the original current value. Electromagnetic stirring is performed during the melting process at a frequency of 5Hz and a stirring current of 500A.

[0034] S2: Remove the oxide scale from the surface of the ingot obtained in S1. The cutting depth is 2mm. After cutting, perform ultrasonic testing and then cut off the riser.

[0035] S3: The pre-treated ingot in S2 is forged, including the first, second and third forging in sequence. After each forging is completed and cooled to room temperature, the surface is polished to remove surface creases and micro-cracks.

[0036] The first heating process is as follows: the billet is heated to 30°C above the β phase transformation point, the deformation method is three upsetting and three drawing, the upsetting deformation amount is 50%, the upsetting rate is 40mm / s, after the single deformation is completed, it is rotated 90° to change direction, and after the end face is completed, the chamfering operation is performed.

[0037] The second heating process is as follows: the billet is heated to 30°C below the β phase transformation point, the deformation method is three upsetting and one drawing, the total deformation is 50%, the upsetting rate is 10mm / s, and the end face is chamfered after the process is completed.

[0038] The third forging process is as follows: the billet is heated to 60°C below the β phase transformation point, and the deformation method is one upsetting and one drawing, with a total deformation of 50% and an upsetting rate of 6 mm / s. After the upsetting is completed, the end face is chamfered. After this forging is completed, it is air-cooled to room temperature.

[0039] S4: After forging, the billet is first solution-treated at 80°C below the β phase transformation point for 20 minutes, then heated to 20°C below the β phase transformation point for a second solution-treatment for 1 hour, followed by oil quenching. After the solution treatment, it is aged at 500°C for 2 hours, then at 600°C for 8 hours, and finally air-cooled to room temperature.

[0040] S5: After the S4 heat treatment, the high-temperature titanium alloy is machined into ø30*200mm bars, and then subjected to cryogenic treatment and surface shot peening. The cryogenic treatment temperature is -100℃ and the time is 6 hours. The shot peening coverage is not less than 200%, and the shot peening intensity is 0.2mmA.

[0041] Example 2 A method for improving the hardenability of high-temperature titanium alloys includes the following steps: S1: During the casting process of Ti65 alloy, Ni element with a mass ratio of 1.2% is introduced in the form of AlNi50 alloy. The melting method is vacuum consumable arc melting, with no less than three melting cycles. The melting voltage is 35V and the current is 15kA. When the remaining mass of the electrode block drops to 10%, 7%, and 4%, the current is gradually reduced to 70%, 50%, and 30% of the original current value. Electromagnetic stirring is performed during the melting process at a stirring frequency of 15Hz and a stirring current of 1000A.

[0042] S2: Remove the oxide scale from the surface of the ingot obtained in S1. The cutting depth is 5mm. After cutting, perform ultrasonic testing and then cut off the riser.

[0043] S3: The pre-treated ingot in S2 is forged, including the first, second and third forging in sequence. After each forging is completed and cooled to room temperature, the surface is polished to remove surface creases and micro-cracks.

[0044] The first heating process is as follows: the billet is heated to 50°C above the β phase transformation point, the deformation method is three upsetting and three drawing, the upsetting deformation amount is 50%, the upsetting rate is 60mm / s, after the single deformation is completed, it is rotated 90° to change direction, and after the end face is completed, the chamfering operation is performed.

[0045] The second heating process is as follows: the billet is heated to 50°C below the β phase transformation point, the deformation method is three upsetting and one drawing, the total deformation is 50%, the upsetting rate is 20mm / s, and the end face is chamfered after the process is completed.

[0046] The third forging process is as follows: the billet is heated to 80°C below the β phase transformation point, and the deformation method is one upsetting and one drawing, with a total deformation of 50% and an upsetting rate of 8mm / s. After the upsetting is completed, the end face is chamfered. After this forging is completed, it is air-cooled to room temperature.

[0047] S4: After forging, the billet is first solution-treated at 120°C below the β phase transformation point for 30 minutes, then heated to 40°C below the β phase transformation point for 2 hours, followed by oil quenching. After the solution treatment, it is aged at 550°C for 4 hours, then aged at 650°C for 16 hours, and finally air-cooled to room temperature.

[0048] S5: After the S4 heat treatment, the high-temperature titanium alloy is machined into ø30*200mm bars, and then subjected to cryogenic treatment and surface shot peening. The cryogenic treatment temperature is -196℃, and the time is 1 hour. The shot peening coverage is not less than 200%, and the shot peening intensity is 0.5mmA.

[0049] Example 3 A method for improving the hardenability of high-temperature titanium alloys includes the following steps: S1: During the casting process of Ti175 alloy, 0.8% Fe and 1.5% Ni by mass are introduced, with Fe introduced in the form of TiFe40 alloy and Ni in the form of TiNi60 alloy. The melting method is vacuum arc melting, with no less than three melting cycles. The melting voltage is 33V and the current is 13kA. When the remaining mass of the electrode block drops to 10%, 7%, and 4%, the current is gradually reduced to 70%, 50%, and 30% of the original current value. Electromagnetic stirring is performed during the melting process at a frequency of 10Hz and a stirring current of 750A.

[0050] S2: Remove the oxide scale from the surface of the ingot obtained in S1. The cutting depth is 3mm. After cutting, perform ultrasonic testing and then cut off the riser.

[0051] S3: The pre-treated ingot in S2 is forged, including the first, second and third forging in sequence. After each forging is completed and cooled to room temperature, the surface is polished to remove surface creases and micro-cracks.

[0052] The first heating process is as follows: the billet is heated to 40°C above the β phase transformation point, the deformation method is three upsetting and three drawing, the upsetting deformation amount is 50%, the upsetting rate is 50mm / s, after the single deformation is completed, it is rotated 90° to change direction, and after the end face is completed, the chamfering operation is performed.

[0053] The second heating process is as follows: the billet is heated to 40°C below the β phase transformation point, the deformation method is three upsetting and one drawing, the total deformation is 50%, the upsetting rate is 15mm / s, and the end face is chamfered after the process is completed.

[0054] The third forging process is as follows: The billet is heated to 70°C below the β phase transformation point, and the deformation method is one upsetting and one drawing, with a total deformation of 50% and an upsetting rate of 7 mm / s. After the upsetting is completed, the end face is chamfered. After this forging is completed, it is air-cooled to room temperature.

[0055] S4: After forging, the billet is first solution-treated at 100°C below the β phase transformation point for 30 minutes, then heated to 30°C below the β phase transformation point for another 1.5 hours, followed by oil quenching. After the solution treatment, it is aged at 500°C for 3 hours, then aged at 630°C for 13 hours, and finally air-cooled to room temperature.

[0056] S5: After the S4 heat treatment, the high-temperature titanium alloy is machined into bars of ø30*200mm, and then subjected to cryogenic treatment and surface shot peening. The cryogenic treatment temperature is -100℃ and the time is 6 hours. The shot peening coverage is not less than 200%, and the shot peening intensity is 0.3mmA.

[0057] Comparative Example 1 Comparative Example 1 uses Ti60 alloy that was not treated with the method for improving the hardenability of high-temperature titanium alloys provided in this invention, as described in Example 1.

[0058] Comparative Example 2 Comparative Example 2 uses Ti65 alloy that was not treated with the method for improving the hardenability of high-temperature titanium alloys provided in this invention, as described in Example 2.

[0059] Comparative Example 3 Comparative Example 3 uses Ti175 alloy that has not been treated with the method for improving the hardenability of high-temperature titanium alloys provided in this invention, as described in Example 3.

[0060] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that the mass of Fe introduced is 3% of the total mass of the alloy.

[0061] Comparative Example 5 The only difference between Comparative Example 5 and Example 1 is that the introduced fast-diffusion component is replaced with Ni element, and the mass of the introduced Ni element is 3% of the total mass of the alloy.

[0062] The hardenability of the alloy materials obtained in Examples 1-3 and Comparative Examples 1-5 was tested using the end-quenching method. A schematic diagram of the end-quenching experiment is shown below. Figure 1 .

[0063] The actual chemical composition of the alloy materials obtained in Example 1 and Comparative Examples 1, 4, and 5 is shown in Table 1. The hardenability results of Example 1 and Comparative Example 1 are shown in Table 1. Figure 2 .

[0064] Table 1 Comparative Example 1 (Ti60) 6.1 3.8 3.7 0.8 0.4 0.3 / / margin Comparative Example 4 (Ti60) 5.8 3.7 3.9 1.0 0.5 0.4 2.1 / margin Comparative Example 5 (Ti60) 6.2 3.9 3.8 0.7 0.6 0.2 / 1.9 margin Example 1 5.9 3.7 3.5 0.8 0.5 0.3 1.1 / margin By comparing the end-quenching test results of Example 1 and Comparative Example 1, it can be found that after the introduction of Fe element, the overall hardness of the material is improved due to solid solution strengthening. The hardness decreases gradually from the surface to the core, and the quenching depth of Ti60 alloy is increased from the original 42mm to 55mm.

[0065] In Comparative Example 4, excessive Fe content led to the formation of a brittle titanium-iron phase inside the ingot, resulting in severe cracking of the ingot during the second forging process, making subsequent operations impossible. In Comparative Example 5, excessive Ni content led to the formation of a brittle titanium-nickel phase inside the ingot, resulting in severe cracking of the ingot during the second forging process, making subsequent operations impossible. The actual chemical composition of the alloy materials obtained in Example 2 and Comparative Example 2 is shown in Table 1, and the hardenability results are shown in Table 2. Figure 3 .

[0066] Table 2 Comparative Example 2 (Ti65) 6.0 4.1 3.4 0.4 0.4 0.5 1.9 1.0 0.05 / margin Example 2 5.8 3.8 3.3 0.5 0.5 0.4 1.9 0.9 0.05 1.1 margin By comparing the end-quenching test results of Example 2 and Comparative Example 2, it can be found that after introducing Ni, the overall hardness of the material is improved due to solid solution strengthening. The hardness decreases gradually from the surface to the core, and the quenching depth of Ti65 alloy is increased from the original 52mm to 58mm.

[0067] The actual chemical composition of the alloy materials obtained in Example 3 and Comparative Example 3 is shown in Table 1, and the hardenability results are shown in Table 2. Figure 3 .

[0068] Table 3 Comparative Example 3 (Ti175) 6.3 1.9 3.6 4.1 0.3 0.9 / / margin 6.3 Example 3 6.4 2 3.5 3.9 0.2 1.1 1.5 0.9 margin 6.4 By comparing the end-quenching test results of Example 3 and Comparative Example 3, it can be found that after introducing Fe and Ni elements, the overall hardness of the material is improved due to solid solution strengthening. The hardness decreases gradually from the surface to the core, and the quenching depth of Ti65 alloy is increased from the original 50mm to 63mm.

[0069] 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 improving the hardenability of high-temperature titanium alloys, characterized in that, Includes the following steps: S1: Fast-diffusion components are introduced through melting during the high-temperature titanium alloy forming process, and an ingot is obtained; S2: Pre-process the ingot obtained in S1; S3: Forging the pre-treated ingot from S2; S4: The high-temperature titanium alloy after forging in S3 is subjected to solution treatment and aging treatment; S5: The high-temperature titanium alloy after S4 heat treatment is processed into profiles of the required specifications. The fast-diffusion component in S1 is one or more of Fe and Ni elements, wherein the Fe element is introduced through any one of AlFe40 alloy and TiFe40 alloy, and the Ni element is introduced through any one of AlNi50 alloy and TiNi60 alloy, and the mass of the Fe element is 0.15%-2% of the total alloy mass, and the mass of the Ni element is 0.8%-1.8% of the total alloy mass; The melting method is vacuum self-consuming arc melting, with no less than three melting cycles. The melting voltage is 30-35V, and the current is 10kA-15kA. When the remaining mass of the electrode block drops to 10%, 7%, and 4%, the current decreases stepwise to 70%, 50%, and 30% of the original current value, respectively. The smelting process is carried out by electromagnetic stirring, with a stirring frequency of 5-15Hz and a stirring current of 500-1000A. The forging in S3 includes a first forging, a second forging, and a third forging in sequence. After each forging is completed and cooled to room temperature, the surface is polished to remove surface creases and microcracks. The solution treatment process in S4 is as follows: first, solution treatment is carried out at 80-120℃ below the β phase transition point for 20-30 minutes, then the temperature is raised to 20-40℃ below the β phase transition point for another 1-2 hours, followed by oil quenching. The aging process is as follows: after the solution treatment, the temperature is first aging at 500-550℃ for 2-4 hours, then aging at 600-650℃ for 8-16 hours, and finally air-cooled to room temperature.

2. The method for improving the hardenability of high-temperature titanium alloys according to claim 1, characterized in that, The high-temperature titanium alloy is a titanium alloy that can serve for a long time at temperatures above 550°C, and the titanium alloy is one of Ti60, Ti65, and Ti175.

3. The method for improving the hardenability of high-temperature titanium alloys according to claim 1, characterized in that, The pretreatment operation in S2 involves cutting off the oxide scale on the surface of the ingot to a depth of 2-5 mm. After cutting, ultrasonic testing is performed, and then the riser is cut off.

4. The method for improving the hardenability of high-temperature titanium alloys according to claim 1, characterized in that, The first heating process is as follows: the billet is heated to 30-50°C above the β phase transformation point, the deformation method is three upsetting and three drawing, the upsetting deformation amount is 50%, the upsetting rate is 40-60mm / s, after the single deformation is completed, the billet is rotated 90° to change direction, and after the three upsetting and drawing are completed, the end face is chamfered.

5. The method for improving the hardenability of high-temperature titanium alloys according to claim 1, characterized in that, The second heating process is as follows: the billet is heated to 30-50°C below the β phase transformation point, the deformation method is three upsetting and one drawing, the total deformation is 50%, the upsetting rate is 10-20mm / s, and the end face is chamfered after the process is completed.

6. The method for improving the hardenability of high-temperature titanium alloys according to claim 1, characterized in that, The third heating process is as follows: the billet is heated to 60-80°C below the β phase transformation point, the deformation method is one upsetting and one drawing, the total deformation is 50%, the upsetting rate is 6-8 mm / s, and the end face is chamfered after the process is completed.

7. The method for improving the hardenability of high-temperature titanium alloys according to claim 1, characterized in that, In step S5, after the high-temperature titanium alloy is processed into profiles of the required specifications, it is subjected to cryogenic treatment and surface shot peening treatment in sequence. The cryogenic treatment temperature is -100 to -196℃, and the time is 1-6 hours; the shot peening coverage is not less than 200%, and the shot peening intensity is 0.2-0.5 mmA.

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