High-strength plastic TA4G alloy and double-temperature-zone step hot drawing preparation method thereof

Abstract

This application provides a high-strength, high-ductility TA4G alloy and its dual-temperature zone stepped hot drawing preparation method. The method involves preparing TA4G alloy ingots through vacuum arc remelting, followed by β-phase region forging, two-stage gradient temperature-controlled rolling, and then dual-temperature zone stepped hot drawing for diameter reduction using a pressure-increasing die. Combined with high-temperature lubrication and precise deformation control, the final product is straightened and centerless ground to obtain medical-grade finished wire. This invention achieves precise temperature gradient control of dynamic recovery and subgrain refinement processes, eliminating the need for intermediate annealing and effectively suppressing work hardening and micropore defects. The resulting TA4G alloy wire has a tensile strength ≥950MPa, elongation after fracture ≥15%, uniform microstructure, and excellent surface quality. The production cycle and energy consumption are significantly reduced, allowing for direct use in surgical implants such as dental implants and bone screws. This provides a stable and feasible solution for the industrialization and domestic production of high-end medical TA4G titanium materials.

Description

Technical Field

[0001] This application relates to a high-strength and ductile TA4G alloy and its dual-temperature zone stepped hot drawing preparation method, belonging to the field of titanium alloy material technology. Background Technology

[0002] Titanium and titanium alloys have become core materials in the field of medical devices due to their low density, high specific strength, excellent resistance to physiological corrosion and biocompatibility. Especially in the field of dental implants, their non-magnetic properties and osseointegration capabilities can meet the needs of long-term implantation and are gradually replacing traditional metal materials.

[0003] However, since TA4G alloy is an α-type titanium alloy with a hexagonal close-packed (HCP) crystal structure, the number of slip systems in the HCP structure is limited. During conventional hot working, TA4G alloy is prone to problems such as work hardening accumulation and uneven plastic deformation. In addition, in unidirectional deformation processes such as drawing, micropores are easily formed inside the material due to tensile stress concentration and local rheological differences. These defects will seriously affect the final performance of the wire, making it difficult for TA4G alloy wire prepared by existing technology to break through the bottleneck of "strength ≥950MPa and elongation ≥15%" for the synergistic performance of strength and plasticity. It cannot simultaneously meet the dual stringent requirements of high strength and high toughness for medical implant materials.

[0004] Currently, the mainstream manufacturing processes for medical titanium wires are divided into two main routes: cold drawing and hot drawing. Both routes have insurmountable technical problems. The cold drawing process relies on a cyclical mode of "multi-pass cold deformation + intermediate annealing". Although the technology is mature, frequent annealing can easily cause grain coarsening, making it impossible to achieve a synergistic improvement in strength and plasticity. Moreover, the cold deformation process can easily exacerbate internal micropore defects, resulting in poor batch stability of the wire. The conventional hot drawing process can alleviate work hardening, but the temperature control is rough, making it impossible to accurately regulate dynamic recovery and microstructure evolution. This can easily cause excessive α-phase fiberization and severe surface oxidation. Furthermore, it relies heavily on empirical parameter adjustment, making it impossible to achieve precise control of the microstructure and stably obtain high-performance wires with a good balance of strength and plasticity.

[0005] In the prior art, Chinese invention patent application CN103406386A discloses a method for preparing TC4 titanium alloy wire. This method adopts a process route of "annealing-film treatment-multi-pass cold drawing". By setting a pressure die in the first die box of cold drawing and using calcium-based or sodium-based wire drawing powder as a lubricant, it aims to improve the cold drawing speed and yield. This patent uses a cold drawing process with a cold drawing + multi-pass annealing mode, which improves production efficiency, but the annealing process is prone to grain coarsening, making it impossible to achieve a synergistic improvement in strength and plasticity.

[0006] Another Chinese invention patent application, CN202411008984.X, discloses a hot drawing process for pure titanium TA4 electronic product parts. This process uses a combination of "cold drawing-annealing-hot drawing," improves surface quality through a composite lubricating layer, and controls the hot drawing temperature between 400-600℃. However, the technical solution of this patent still has significant shortcomings. The hot drawing process uses multi-pass circumferential compression deformation, which cannot meet the control requirements of uniform equiaxed crystals, and the effect of work hardening suppression is limited.

[0007] Therefore, developing a TA4G alloy wire preparation process that can be precisely controlled at the microstructure level to suppress work hardening and porosity defects and achieve both strength and plasticity has become an urgent problem to be solved in this field. Summary of the Invention

[0008] To address the aforementioned issues, a high-strength and high-ductility TA4G alloy and its dual-temperature zone stepped hot drawing preparation method are provided. Through the synergistic control of gradient temperature-controlled rolling and dual-temperature zone stepped hot drawing, a high-strength and high-ductility synergistic match of ≥950MPa tensile strength and ≥15% elongation of TA4G alloy wire is achieved without the need for intermediate annealing. At the same time, the production cycle is significantly shortened, production energy consumption is reduced, and the batch stability and surface quality of the wire are improved. The product can meet the industrial mass production needs of surgical implants such as dental implants and medical bone screws, providing a feasible solution for the domestic preparation of high-end medical TA4G titanium materials.

[0009] According to one aspect of this application, a method for preparing high-strength, high-ductility TA4G alloy by dual-temperature zone stepped hot drawing is provided, comprising the following steps: (1) Ingot preparation: TA4G alloy ingots were prepared using a vacuum consumable melting process; (2) Forging: The TA4G alloy ingot is forged at the β phase transformation temperature T β After holding at +50℃, the billet is forged using a high-speed forging machine to obtain the forging billet. (3) Gradient temperature controlled rolling: The forging billet is hot rolled in two passes, one of which is at T β The rolling process is carried out at -80~100℃, with the second rolling stage performed at T... β The rolling process is carried out at -(120~140)℃, and the final rolling temperature is controlled at 740~770℃ to obtain TA4G alloy rolled bars. (4) Dual-temperature zone stepped hot drawing: The TA4G alloy rolled bar is subjected to two-stage stepped hot drawing to reduce the diameter using a pressure die drawing machine. Lubricant is added during the first stage of hot drawing, and the temperature is controlled at 620~650℃. The temperature of the second stage of hot drawing is controlled at 550~580℃. (5) Straightening and length setting and post-processing: The drawn wire blanks are straightened and length set, centerless grinding and polishing are performed in sequence to obtain high-strength and plastic TA4G alloy finished wires.

[0010] Optionally, in step (1), grade 1 or higher sponge titanium, reduced iron powder, and TiO2 are used for batching, and TA4G alloy ingots are prepared through three vacuum consumable melting processes. The raw material ratio and vacuum melting process can be adjusted according to the actual situation. This application does not impose specific limitations, as long as the final TA4G alloy ingot conforms to the GB / T 3620.1-2016 standard. Alternatively, TA4G alloy ingots that conform to the standard can be used directly.

[0011] The vacuum self-consuming melting process can be controlled in three stages: the first melting stage has a vacuum degree ≤1Pa, a current of 13-15kA, and a voltage of 31-33V; the second melting stage has a vacuum degree ≤0.8Pa, a current of 23-25kA, and a voltage of 32-33V; and the third melting stage has a vacuum degree ≤0.5Pa and a current of 25-26kA.

[0012] Optionally, in step (2), the heating temperature for billet forging is T. β +50℃, holding time is 5.5~6.5h, forging temperature ≥850℃, and cumulative deformation of billet forging is 85%~90%.

[0013] Specifically, by limiting the temperature of the initial forging, the ingot is ensured to soften sufficiently and the grains to break down. β The heating temperature of +50℃ ensures that the ingot is completely in the β single-phase region, and the limited holding time ensures uniform internal temperature of the ingot, avoiding forging cracks caused by insufficient local temperature. At the same time, the limited total deformation can fully break down the initial coarse grains of the ingot and eliminate defects such as porosity and shrinkage cavities inside the ingot.

[0014] Optionally, in step (3), the heat preservation time before the first rolling is 2.5~3.5h, and the cumulative deformation is controlled at 75%~80%.

[0015] Optionally, in step (3), the holding time before the second rolling is 80~100min, the final rolling temperature is 750-780℃, and the cumulative deformation is ≥98.5%.

[0016] Specifically, by limiting the rolling parameters for a single heat, the temperature of the forged billet can be made uniform, ensuring sufficient dynamic recrystallization while avoiding billet cracking caused by large single deformation. In the secondary heat rolling process, T... β- Incomplete recrystallization at (120~140)℃ allows the original coarse grains of the alloy to be sheared and broken and undergo dynamic recovery, resulting in elongated large grains, which is conducive to dislocation slip. Ultimately, a uniform equiaxed α-grain structure with a grain size of 20-25μm is obtained, which leads to improved plasticity of the alloy and lays the microstructure foundation for uniform deformation in subsequent hot drawing.

[0017] Optionally, in step (4), molybdenum disulfide is used as a high-temperature lubricant during the first stage of hot drawing.

[0018] Optionally, in step (4), the pulling rate during the pulling process is 1-2 m / min.

[0019] Optionally, in step (4), the deformation amount per pass is controlled at 13~15%, and the cumulative deformation amount in two stages is 35~45%, to obtain TA4G alloy wire blank.

[0020] Among them, 1) First hot drawing: a pressure-boosting die and molybdenum disulfide (MoS2) lubricant are used to control the hot drawing temperature at 620~650℃ (in the dynamic recovery dominant zone below the phase transformation point of TA4G alloy), the deformation rate per pass is 13-15%, and the radial pressure is 10-30MPa; the radial positive pressure provided by the pressure-boosting die offsets the local tensile stress concentration during the drawing process, promotes the plastic flow of metal under triaxial compressive stress, and compacts potential micropores. At the same time, the MoS2 lubricant forms a stable layered lubricating film at 620~650℃, reduces the friction coefficient between the die and the wire surface, avoids die sticking and surface scratches, inhibits the formation of oxide layer, and finally obtains an intermediate state wire with a smooth surface and dense interior.

[0021] 2) Second hot drawing: The hot drawing temperature is controlled at 550~580℃, and the deformation rate per pass is 13-15%. The degree of dynamic recovery and recrystallization is controlled by temperature gradient to alleviate the dislocation entanglement accumulated after the first hot drawing, promote subgrain refinement and subgrain boundary reorganization, avoid work hardening saturation, and at the same time suppress the excessive fiberization of α phase along the drawing direction, and retain some equiaxed crystal characteristics to ensure plasticity.

[0022] Optionally, in step (5), the length of the straightened wire is 2500~3000mm, and the single-pass grinding amount of the centerless grinding is less than 0.02mm.

[0023] According to another aspect of this application, a high-strength and ductile TA4G alloy is also provided. The high-strength and ductile TA4G alloy wire prepared by the above preparation method has a tensile strength ≥950MPa and an elongation ≥15%.

[0024] The beneficial effects of this application include, but are not limited to: 1. The high-strength and ductile matching TA4G alloy dual-temperature zone stepped hot drawing preparation method of this application first prepares 20-25μm uniform equiaxed α grains in the pre-rolling stage, which significantly improves the deformation coordination of the subsequent hot drawing and avoids stress concentration caused by uneven microstructure; the pressure design of the first hot drawing and the MoS2 lubrication work together to compact micropores from the source and protect the surface integrity; the temperature gradient of the second hot drawing precisely alleviates work hardening, achieves a balance between dynamic recovery and deformation strengthening, and finally eliminates pore defects, so as to increase the wire elongation to more than 15%.

[0025] 2. The high-strength and ductile matching TA4G alloy dual-temperature zone stepped hot drawing method of this application: The first hot drawing is carried out at 620~650℃, which is in the dynamic recovery dominant zone. The pressure die provides radial compressive stress to offset the local tensile stress concentration during the drawing process and compact potential micropores. At the same time, a high-temperature stable molybdenum disulfide lubricant is used to form an effective lubricating film to avoid die sticking, surface scratches and oxidation, and to obtain an intermediate state wire with a smooth surface and dense interior. The second hot drawing temperature is reduced to 550~580℃. The degree of dynamic recovery and recrystallization is controlled by temperature gradient, which alleviates the dislocation entanglement accumulated in the previous processing, promotes subgrain refinement and reorganization, avoids work hardening saturation, and inhibits excessive fibrousization of the α phase, retaining some equiaxed crystal characteristics to ensure ductility.

[0026] 3. The TA4G alloy wire prepared in this application has a tensile strength ≥950MPa and an elongation ≥15%, and its mechanical properties fully meet and exceed the standard GB / T 13810. The 2017 requirements call for providing domestically produced raw material solutions for dental implants that offer "high performance and high stability," which can drive down the price of civilian implants and promote their widespread use in primary healthcare. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 Metallographic micrographs of 20-25 μm of the TA4G alloy rolled bars prepared in Examples 1-3 of this application; Figure 2 Metallographic micrograph of the TA4G alloy finished wire prepared in Example 1 of this application; Figure 3 The engineering stress-strain curve of the TA4G alloy finished wire of Example 1 of this application; Figure 4 This is a metallographic image of Comparative Example 1 of this application. Detailed Implementation

[0028] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods in the art or as per the product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described in this patent are for illustrative purposes only.

[0030] In this application, the β phase transformation temperature (T4) of the TA4G alloy was determined by differential thermal analysis (DTA). β ): 943℃ Example 1 The preparation method of TA4G alloy wire includes the following steps: (1) Ingot preparation: TA4G alloy ingots were prepared using a vacuum consumable melting process; (2) Forging of billet: The heating temperature before forging of billet is 1000℃, the holding temperature is 5.5h, the forging temperature is 900℃, the cumulative deformation of forging of billet is 87.8%, and the forging billet is obtained; (3) Gradient temperature control rolling: The forging billet is hot rolled in two heats. During the first heat rolling, the rolling temperature is 845℃, the holding temperature is 3.5h, and the cumulative deformation is 78.2%. During the second heat rolling, the pre-rolling temperature is 824℃, the holding temperature is 80min, the final rolling temperature is 768℃, and the cumulative deformation is 98.9%.

[0031] (4) Dual-temperature zone stepped hot drawing: The TA4G alloy rolled bar is subjected to two-stage stepped hot drawing to reduce the diameter using a pressure-boosting die drawing machine. In the first stage of hot drawing, molybdenum disulfide is used as a high-temperature lubricant. The overall drawing speed is 2m / min, and the deformation per pass is controlled at 14%. The first stage hot drawing temperature is 620℃, the second stage hot drawing temperature is 580℃, and the cumulative deformation is 43.5%.

[0032] (5) Straightening and post-processing: The coiled wire is straightened to a length of 2800 mm using a slide straightener. The centerless grinding amount is less than 0.02 mm each time, and finally 4.0 mm Φ TA4G alloy wire is obtained.

[0033] Example 2 The preparation method of TA4G alloy wire includes the following steps: (1) Ingot preparation: TA4G alloy ingots were prepared using a vacuum consumable melting process; (2) Forging of billet: The heating temperature before forging of billet is 1000℃, the holding temperature is 6.5h, the forging temperature is 850℃, the cumulative deformation of the forging of billet is 85%, and the forging billet is obtained; (3) Gradient temperature control rolling: The forging billet is hot rolled in two stages. In the first stage, the rolling temperature is 860℃, and the holding time is 2.5-3.5h, with a cumulative deformation of 80%. In the second stage, the pre-rolling temperature is 815℃, the holding time is 80min, and the final rolling temperature is 770℃, with a cumulative deformation of 91.2%.

[0034] (4) Dual-temperature zone stepped hot drawing: The TA4G alloy rolled bar is subjected to two-stage stepped hot drawing to reduce the diameter using a pressure-boosting die drawing machine. In the first stage of hot drawing, molybdenum disulfide is used as a high-temperature lubricant. The overall drawing speed is 2m / min, and the deformation per pass is controlled at 14.5%. The first stage hot drawing temperature is 650℃, the second stage hot drawing temperature is 550℃, and the cumulative deformation is 39.6%.

[0035] (5) Straightening and post-processing: The coiled wire is straightened to a length of 2800 mm using a slide straightener. The centerless grinding amount is less than 0.02 mm each time, and finally 5.0 mm Φ4G alloy wire is obtained.

[0036] Example 3 The preparation method of TA4G alloy wire includes the following steps: (1) Ingot preparation: TA4G alloy ingots were prepared using a vacuum consumable melting process; (2) Forging of billet: The heating temperature before forging of billet is 1000℃, the holding temperature is 6.0h, the forging temperature is 880℃, the cumulative deformation of billet forging is 88.3%, and the forging billet is obtained; (3) Gradient temperature control rolling: The forging billet is hot rolled in two heats. During the first heat rolling, the rolling temperature is 950℃, the holding time is 3.5h, and the cumulative deformation is 79.0%. During the second heat rolling, the pre-rolling temperature is 800℃, the holding time is 100min, the final rolling temperature is 752℃, and the cumulative deformation is 99.4%.

[0037] (4) Dual-temperature zone stepped hot drawing: The TA4G alloy rolled bar is subjected to two-stage stepped hot drawing to reduce the diameter using a pressure-boosting die drawing machine. In the first stage of hot drawing, molybdenum disulfide is used as a high-temperature lubricant. The overall drawing speed is 1.5 m / min, and the deformation per pass is controlled at 13.2%. The first stage hot drawing temperature is 620℃, the second stage hot drawing temperature is 550℃, and the cumulative deformation is 35%.

[0038] (5) Straightening and post-processing: The coiled wire was straightened to a length of 2800 mm using a slide straightener. The centerless grinding amount was less than 0.02 mm each time, and finally 6.0 mm Φ4G alloy wire was obtained.

[0039] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in step (4), the second rolling temperature is 860°C and the final rolling temperature is 793°C; the rest of the operations are the same, and finally a Φ4.0mm finished TA4G alloy wire is obtained.

[0040] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in step (5), conventional cold drawing deformation is used. Under room temperature conditions, the deformation amount per pass is 8~12%, the drawing rate is ≤3m / min, and the rest of the operation is the same. Finally, a finished TA4G alloy wire with a diameter of Φ4.0mm is obtained.

[0041] Experimental Example 1. The rolled bars prepared in Examples 1-3 were tested, and their metallographic structures were obtained as follows: Figure 1 As shown.

[0042] from Figure 1 As can be seen, by controlling the final rolling temperature during the rolling process, dynamic recovery is activated without triggering recrystallization, resulting in 20-25μm uniform equiaxed α grains. This significantly reduces stress concentration and void initiation caused by uneven microstructure during drawing, thereby improving the alloy's strength. At the same time, it endows the alloy with continuous work hardening and plastic deformation capabilities, ultimately enabling the successful acquisition of TA4G alloy wire with both high strength and high plasticity.

[0043] 2. The mechanical properties of the finished TA4G alloy wires from Examples 1-3 and Comparative Examples 1-2 were tested. The testing methods were carried out in accordance with GB / T 13810-2017 "Titanium and Titanium Alloy Processed Materials for Surgical Implants". The test results of the mechanical properties of the finished TA4G alloy wires from Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.

[0044] Table 1. Test results of mechanical properties of finished TA4G alloy wire

[0045] The experimental results above show that R can be prepared using the preparation method specified in this application. m TA4G alloy wire, with stable mechanical properties of 977–983 MPa, Rp0.2 of 824–836 MPa, and A of 17.0–19.0%, fully meets and exceeds the standard GB / T 13810. In accordance with the mechanical property requirements of 2017, the finished TA4G alloy wire prepared in this application has excellent plasticity and strength.

[0046] In addition, by Figure 2 It is known that the metallographic structure of the TA4G alloy finished wire obtained in this application is equiaxed α grains with uniform and controllable grain size of 20~25μm, clear and continuous grain boundaries, no coarse abnormally large grains, no micropores or microcracks in the internal structure, and the α phase does not undergo excessive fiberization along the drawing direction. The uniformity and density of the structure are far superior to those of conventional cold drawing and traditional hot drawing processes.

[0047] Depend on Figure 3 It is known that the engineering stress-strain curve of the TA4G alloy finished wire of this application is smooth and continuous, without obvious yield teeth, with a wide plastic deformation range and no sudden stress drop before fracture. The curve corresponds to a tensile strength ≥950MPa and an elongation after fracture ≥15%, achieving a simultaneous match between high strength and high plasticity. The curve characteristics are due to the precise control of dynamic recovery, dislocation configuration and subgrain evolution by dual-temperature zone stepped hot drawing. The first stage of high-temperature drawing at 620~650℃ effectively alleviates work hardening and compacts internal micropores. The second stage of low-temperature gradient drawing at 550~580℃ promotes subgrain refinement and reorganization, balancing deformation strengthening and plasticity retention. At the same time, the pressure die and high-temperature lubrication work together to eliminate surface defects and stress concentration, so that the wire deforms uniformly and stress is transferred stably during the stretching process.

[0048] Comparing Examples 1-3 and Comparative Example 1, it can be seen that the tensile strength and yield strength of the finished TA4G alloy wire prepared in Comparative Example 1 are both lower than those in Examples 1-3. This indicates that the present invention, through precise control of gradient temperature rolling, achieves dynamic recovery-dominated grain evolution in the α+β two-phase region, obtaining a uniform equiaxed α-grain structure of 20-25 μm. In contrast, the rolling temperature and final rolling temperature of Comparative Example 1 are too high, failing to achieve precise control of equiaxed grains, thus its strength performance is inferior to that of the examples. Furthermore... Figure 4 The image shows the metallographic structure of Comparative Example 1, combined with... Figure 4 It can be seen that because TA4G alloy is prone to work hardening, cold deformation and multiple intermediate annealing are used in the processing, resulting in large alloy grain size and micropores, which does not meet the requirements for product use.

[0049] The tensile strength and yield strength of the finished TA4G alloy wire prepared in Comparative Example 2 are both lower than those in Examples 1-3. This shows that the dual-temperature zone stepped hot drawing process of the present invention, combined with the synergistic design of the pressure-boosting die and MoS2 lubricant, achieves plastic deformation in the dynamic recovery-dominant region of the α single-phase region. It not only compacts micropores and inhibits the accumulation of work hardening through triaxial compressive stress, but also uses temperature gradient to regulate the evolution of dislocation configuration, promoting subgrain refinement and reorganization. In contrast, the conventional cold drawing process used in Comparative Example 2 relies solely on room temperature work hardening to achieve strength improvement, which easily leads to dense dislocation entanglement. At the same time, the cold drawing process is prone to defects such as micropores and microcracks, and cannot achieve a balance between strengthening and plasticity. Therefore, the strength and comprehensive performance are lower than those of the examples.

[0050] In summary, the preparation method specified in this application can produce high-strength, high-ductility TA4G alloy wire for dental use, providing qualified raw materials for dental implant products and increasing the market share of domestically produced implants.

[0051] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing high-strength, high-ductility TA4G alloy by dual-temperature zone stepped hot drawing, characterized in that, Includes the following steps: (1) Ingot preparation: TA4G alloy ingots were prepared using a vacuum consumable melting process; (2) Forging: The TA4G alloy ingot is forged at the β phase transformation temperature T β After holding at +50℃, the billet is forged using a high-speed forging machine to obtain the forging billet. (3) Gradient temperature controlled rolling: The forging billet is hot rolled in two passes, one of which is at T β The rolling process is carried out at -80~100℃, with the second rolling stage performed at T... β The rolling process is carried out at -(120~140)℃, and the final rolling temperature is controlled at 740~770℃ to obtain TA4G alloy rolled bars. (4) Dual-temperature zone stepped hot drawing: The TA4G alloy rolled bar is subjected to two-stage stepped hot drawing to reduce the diameter using a pressure die drawing machine. Lubricant is added during the first stage of hot drawing, and the temperature is controlled at 620~650℃. The temperature of the second stage of hot drawing is controlled at 550~580℃. (5) Straightening and length setting and post-processing: The drawn wire blanks are straightened and length set, centerless grinding and polishing are performed in sequence to obtain high-strength and plastic TA4G alloy finished wires.

2. The preparation method according to claim 1, characterized in that, In step (1), TA4G alloy ingots are prepared by using grade 1 or higher sponge titanium, reduced iron powder and TiO2 as raw materials and by three vacuum self-consumption melting processes.

3. The preparation method according to claim 1, characterized in that, In step (2), the heating temperature for billet forging is T. β +50℃, holding time is 5.5~6.5h, forging temperature ≥850℃, and cumulative deformation of billet forging is 85%~90%.

4. The preparation method according to claim 1, characterized in that, In step (3), the heat preservation time before the first rolling is 2.5~3.5h, and the cumulative deformation is controlled at 75%~80%.

5. The preparation method according to claim 1, characterized in that, In step (3), the holding time before the second rolling is 80~100min, the final rolling temperature is 750-780℃, and the cumulative deformation is ≥98.5%.

6. The preparation method according to claim 1, characterized in that, In step (4), molybdenum disulfide is used as a high-temperature lubricant during the first stage of hot drawing.

7. The preparation method according to claim 1, characterized in that, In step (4), the pulling rate is 1-2 m / min during the pulling process.

8. The preparation method according to claim 1, characterized in that, In step (4), the deformation amount per pass is controlled at 13~15%, and the cumulative deformation amount in two stages is 35~45%, thus obtaining TA4G alloy wire blank.

9. The preparation method according to claim 1, characterized in that, In step (5), the length of the straightened wire is 2500~3000mm, and the single-pass grinding amount of the centerless grinding is less than 0.02mm.

10. A high-strength, high-ductility TA4G alloy, characterized in that, The high-strength and ductile TA4G alloy wire prepared by any one of claims 1-9 has a tensile strength ≥950MPa and an elongation ≥15%.

Images