Preparation method for improving the surface finish and properties of TB14 titanium alloy wire for fasteners

Abstract

This invention provides a method for preparing TB14 titanium alloy wire for fasteners with improved surface precision and performance, comprising the following steps: S1, forging: forging TB14 ingots to obtain titanium billets; S2, rolling; S3, rotary forging, which requires no heat treatment; S4, roll drawing, where intermediate wire is vacuum annealed and then roll drawn to obtain the finished wire product; no heat treatment is required during roll drawing. This invention uses rotary forging and roll drawing for cold working of the wire, ensuring that the dimensional tolerance of wire products from Φ2.0mm to Φ4.9mm can be continuously and stably maintained within the range of 0 to 0.02mm, and the surface roughness Ra ≤ 0.5μm. The entire wire production process is acid-free and electrolytic-free, with no hydrogen, oxygen, or nitrogen addition during production, resulting in high component purity.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy wire preparation technology, specifically a preparation method for improving the surface precision and performance of TB14 titanium alloy wire for fasteners. Background Technology

[0002] TB14 titanium alloy possesses characteristics such as low density, high specific strength, strong corrosion resistance, excellent cold working properties, and electrode potential that matches those of composite materials. Therefore, TB14 titanium alloy wire is commonly used in the manufacture of high-end aerospace fasteners.

[0003] Traditional wire drawing for diameter reduction primarily employs fixed-die hot drawing. This method readily leads to the wire absorbing harmful elements such as nitrogen, hydrogen, and oxygen from the air under heat, degrading material properties. During drawing, significant sliding friction exists between the fixed die and the wire, causing die wear and resulting in increased dimensional tolerances and surface scratches, creating continuous quality defects. Furthermore, after drawing, electrolytic polishing or acid pickling is necessary to remove graphite or phosphoric acid lubricants from the wire surface, leading to high energy consumption and pollution in wire production. Summary of the Invention

[0004] To address the aforementioned technical problems, a method for preparing TB14 titanium alloy wire for fasteners that improves surface precision and performance is provided.

[0005] The technical means employed in this invention are as follows:

[0006] A method for preparing TB14 titanium alloy wire for improving the surface accuracy and performance of fasteners includes the following steps:

[0007] S1. Forging: After removing the outer skin and riser from the TB14 ingot, a billet is obtained. The billet is then forged to obtain a titanium billet. The forging process uses a two-fire method. The first forging uses a three-upsetting and three-drawing method. The initial forging temperature of the first forging is 1050-1150℃, and it is held for 3 hours. The final forging temperature is >700℃, and the deformation of upsetting and drawing is 65-70%. The second forging uses a two-upsetting and two-drawing method. The initial forging temperature of the second forging is 900-1000℃, and it is held for 3 hours. The final forging temperature is >600℃, and the deformation of upsetting and drawing is 60-65%.

[0008] S2. Rolling: After the titanium billet is polished to a metallic luster and free of visible defects, it is rolled to obtain wire rod. The rolling process adopts a two-stage rolling process. The rolling process parameters for the first stage are: temperature 850-900℃, holding time 2h, rolling speed 2m / s, final rolled size Φ60mm, 13 rolling passes, and rolling deformation 75%. The rolling process parameters for the second stage are: temperature 800-850℃, holding time 2h, 10 rolling passes, final rolled size Φ10mm, and rolling deformation 97%.

[0009] S3. Rotary Forging: The wire rod undergoes a rounding-skinning process. Rounding is performed using a hot drawing machine at temperatures below 800℃ to remove surface defects, resulting in a rounded size of Φ9.5mm. Skinning is performed using a centerless grinding lathe to remove oxide scale and surface defects, resulting in a skinned size of Φ9.0mm. Rotary forging is then performed to obtain intermediate wire. The rotary forging process uses a rotary forging machine, undergoing 7 passes, each reducing the diameter by 0.5mm, reducing the diameter of the Φ9.0mm wire to Φ5.5mm. Hydraulic oil is used for lubrication during rotary forging, and the forging rate is no greater than 0.5 / min. No heat treatment is required during rotary forging.

[0010] S4. Roller drawing: The intermediate filament obtained in step S3 exhibits work hardening. To facilitate subsequent roller drawing, the intermediate filament needs to undergo vacuum annealing heat treatment before roller drawing to obtain the filament product.

[0011] The vacuum annealing heat treatment temperature is 700℃~810℃, the holding time is 1h~2h, and the cooling method is water cooling;

[0012] Before the roller drawing process, a water-soluble lubricant needs to be evenly applied to the intermediate filament.

[0013] During the roller drawing process, the diameter of the intermediate wire is reduced to Φ4.3-Φ4.9mm, Φ3.5-Φ3.9mm, Φ2.0-Φ2.4mm or Φ1.8-2.0mm, and no heat treatment is required during the roller drawing process.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. This invention employs rotary forging and roll drawing methods for cold reduction and cold drawing of TB14 titanium alloy wire. Cold working is an important way to improve performance by refining the microstructure. Rotary forging has the advantages of simple die replacement, smooth surface finish, and high dimensional accuracy. Roll drawing has the advantages of low rolling friction, high wire surface quality, large deformation per pass, and uniform material microstructure after deformation. Therefore, this invention uses rotary forging and cold drawing to improve the surface accuracy and performance of TB14 titanium alloy wire.

[0016] 2. Both the forging and rolling processes used large deformation and low processing temperatures, which effectively ensured that the coarse structure was broken up to a certain extent, the internal structure was improved, and the plasticity was increased.

[0017] 3. The entire process of producing the silk material is free from acid washing and electrolysis. There is no addition of hydrogen, oxygen, or nitrogen during the production process, resulting in high purity of components.

[0018] 4. Both rotary forging and roll drawing are cold working processes. Cold-worked wire products are characterized by high dimensional accuracy. The dimensional tolerance of wire products with diameters from Φ2.0mm to Φ4.9mm can be continuously and stably maintained within the range of 0 to 0.02mm, and the surface roughness Ra of the wire is ≤0.5μm.

[0019] 5. Cold-worked wire products have excellent comprehensive properties. Cold working can refine the wire grains, improving the grain size to grade 10; improve the upsetting performance of TB14 wire, with 80% compression deformation without cracking; and ensure the consistency and stability of various mechanical properties of the wire, meeting the requirements of GJB 9584-2018 "Specification for Titanium-Niobium Alloy Wires".

[0020] Based on the above reasons, this invention can be widely applied in fields such as titanium alloy wire preparation. Attached Figure Description

[0021] 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.

[0022] Figure 1 This is a transverse microstructure diagram of the 4.92mm drawn TB14 wire in a specific embodiment of the present invention.

[0023] Figure 2 This is a longitudinal microstructure diagram of the 4.92mm drawn TB14 wire in a specific embodiment of the present invention.

[0024] Figure 3 This is a transverse microstructure diagram of the 3.92mm drawn TB14 wire in a specific embodiment of the present invention.

[0025] Figure 4 This is a longitudinal microstructure diagram of the 3.92mm drawn TB14 wire in a specific embodiment of the present invention.

[0026] Figure 5 This is a transverse microstructure diagram of the 2.43mm drawn TB14 wire in a specific embodiment of the present invention.

[0027] Figure 6 This is a longitudinal microstructure diagram of the 2.43mm drawn TB14 wire in a specific embodiment of the present invention.

[0028] Figure 7 This is a surface state diagram of a typical specification of TB14 wire after upsetting in a drawn state, according to a specific embodiment of the present invention. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0031] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0032] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0033] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0034] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0035] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0036] A method for preparing TB14 titanium alloy wire for improving the surface accuracy and performance of fasteners includes the following steps:

[0037] S1. Forging: After removing the outer skin and riser from the TB14 ingot, a billet is obtained. The billet is then forged to obtain a titanium billet. The forging process uses a two-fire method. The first forging uses a three-upsetting and three-drawing method. The initial forging temperature of the first forging is 1050-1150℃, and it is held for 3 hours. The final forging temperature is >700℃, and the deformation of upsetting and drawing is 65-70%. The second forging uses a two-upsetting and two-drawing method. The initial forging temperature of the second forging is 900-1000℃, and it is held for 3 hours. The final forging temperature is >600℃, and the deformation of upsetting and drawing is 60-65%.

[0038] S2. Rolling: After the titanium billet is polished to a metallic luster and free of visible defects, it is rolled to obtain wire rod. The rolling process adopts a two-stage rolling process. The rolling process parameters for the first stage are: temperature 850-900℃, holding time 2h, rolling speed 2m / s, final rolled size Φ60mm, 13 rolling passes, and rolling deformation 75%. The rolling process parameters for the second stage are: temperature 800-850℃, holding time 2h, 10 rolling passes, final rolled size Φ10mm, and rolling deformation 97%.

[0039] S3. Rotary Forging: The wire rod undergoes a rounding-skinning process. Rounding is performed using a hot drawing machine at temperatures below 800℃ to remove surface defects, resulting in a rounded size of Φ9.5mm. Skinning is performed using a centerless grinding lathe to remove oxide scale and surface defects, resulting in a skinned size of Φ9.0mm. Rotary forging is then performed to obtain intermediate wire. The rotary forging process uses a rotary forging machine, undergoing 7 passes, each reducing the diameter by 0.5mm, reducing the diameter of the Φ9.0mm wire to Φ5.5mm. Hydraulic oil is used for lubrication during rotary forging, and the forging rate is no greater than 0.5 / min. No heat treatment is required during rotary forging.

[0040] S4. Roller drawing: The intermediate filament obtained in step S3 exhibits work hardening. To facilitate subsequent roller drawing, the intermediate filament needs to undergo vacuum annealing heat treatment before roller drawing to obtain the filament product.

[0041] The vacuum annealing heat treatment temperature is 700℃~810℃, the holding time is 1h~2h, and the cooling method is water cooling;

[0042] Before the roller drawing process, a water-soluble lubricant needs to be evenly applied to the intermediate filament.

[0043] During the roller drawing process, the diameter of the intermediate wire is reduced to Φ4.3-Φ4.9mm, Φ3.5-Φ3.9mm, Φ2.0-Φ2.4mm or Φ1.8-2.0mm, and no heat treatment is required during the roller drawing process.

[0044] Example 1

[0045] A method for preparing TB14 titanium alloy wire for improving the surface accuracy and performance of fasteners includes the following steps:

[0046] S1: Using TB14 ingots with uniform composition and a Φ300mm specification, forging is performed using a 2000t hydraulic press. The first forging temperature is 1050℃, held for 3 hours, and the final forging temperature is >700℃, with an upsetting and elongation deformation of 65%. The second forging temperature is 950℃, held for 3 hours, and the final forging temperature is >600℃, with an upsetting and elongation deformation of 60%.

[0047] S2: After surface treatment of the titanium billet forged in step S1, a reciprocating rolling mill is used. The first rolling pass is at a temperature of 850℃, held for 2 hours, with a rolling speed of 2 m / s, a final rolled size of Φ60 mm, 13 rolling passes, and a rolling deformation of 75%. The second rolling pass is at a temperature of 800℃, held for 2 hours, with 10 rolling passes, a final rolled size of Φ10 mm, and a rolling deformation of 97%.

[0048] S3: Perform a rounding and peeling process on the wire rod from step S2. Then, using a rotary forging mill, reduce the diameter of the Φ9.0mm wire to Φ5.5mm in 7 passes, with each pass reducing the diameter by 0.5mm. Hydraulic oil is used for lubrication during the rotary forging process. The wire feeding rate during rotary forging is no more than 0.5 / min, and no heat treatment is required during the rotary forging process.

[0049] S4: The intermediate filament obtained in step S3 undergoes vacuum annealing heat treatment at a temperature of 690–720℃ for 1–2 hours, using water cooling. A water-soluble lubricant is then evenly applied to the annealed filament, followed by roller drawing. The Φ5.5mm wire is reduced to Φ4.92mm in one pass using a continuous-drawing roller drawing machine, with a deformation of 19.9%.

[0050] The dimensional inspection results of the Φ4.92mm drawn TB14 wire prepared in this embodiment are shown in Table 1. Table 1 shows that the wire has high precision, with a tolerance within 0-0.02mm and a surface roughness Ra≤0.5μm. The mechanical property test results of the Φ3.92mm drawn TB14 wire are shown in Table 2. Table 2 shows that the various mechanical properties of the wire are consistent and stable.

[0051] Table 1. Dimensional Inspection Results of TB14 Wire in Φ4.92mm Drawing State

[0052] test points Test point 1 Test point 2 Test point 3 Test point 4 Test point 5 Test point 6 Test point 7 Size / mm Φ4.926 Φ4.922 Φ4.913 Φ4.915 Φ4.916 Φ4.910 Φ4.922 Roughness / μm 0.456 0.434 0.471 0.452 0.485 0.456 0.472

[0053] Table 2. Test results of mechanical properties of TB14 wire in drawn state with a diameter of Φ4.92mm.

[0054] test points Test point 1 Test point 2 Test point 3 Test point 4 Test point 5 Test point 6 Tensile strength / MPa 680 684 687 684 685 685 Yield strength / MPa 621 623 626 621 624 626 Elongation / % 14.2 14.8 13.6 13.5 13.1 12.9 Reduction of area / % 82 86 85 84 82 84 Shear strength / MPa 388 389 391 392 385 384

[0055] Example 2

[0056] A method for preparing TB14 titanium alloy wire for improving the surface accuracy and performance of fasteners includes the following steps:

[0057] S1: TB14 ingots with uniform composition and a Φ350mm specification are used for forging on a 2000t hydraulic press. The first forging process begins at 1150℃, holds for 3 hours, and ends at a final forging temperature >700℃, with an upsetting and elongation deformation of 68%. The second forging process begins at 1000℃, holds for 3 hours, and ends at a final forging temperature >600℃, with an upsetting and elongation deformation of 63%.

[0058] S2: After surface treatment of the titanium billet forged in step S1, a reciprocating rolling mill is used. The first rolling pass is at a temperature of 900℃, a holding time of 2 hours, a rolling speed of 2 m / s, a final rolled size of Φ60 mm, 13 rolling passes, and a rolling deformation of 75%. The second rolling pass is at a temperature of 850℃, a holding time of 2 hours, 10 rolling passes, a final rolled size of Φ10 mm, and a rolling deformation of 97%.

[0059] S3: Perform a rounding and peeling process on the wire rod from step S2. Then, using a rotary forging mill, reduce the diameter of the Φ9.0mm wire to Φ5.5mm in 7 passes, with each pass reducing the diameter by 0.5mm. Hydraulic oil is used for lubrication during the rotary forging process. The wire feeding rate during rotary forging is no more than 0.5 / min, and no heat treatment is required during the rotary forging process.

[0060] S4: The intermediate filament obtained in step S3 undergoes vacuum annealing heat treatment at a temperature of 690–720℃ for 1–2 hours, using water cooling. After annealing, a water-soluble lubricant is evenly applied, followed by roller drawing. The Φ5.5mm wire is reduced to Φ3.92mm in one pass using a continuous-drawing roller drawing machine, with a deformation of 49.2%.

[0061] The dimensional inspection results of the Φ3.92mm drawn TB14 wire prepared in this embodiment are shown in Table 3. Table 3 shows that the wire has high precision, with a tolerance within 0-0.02mm and a surface roughness Ra≤0.5μm. The mechanical property test results of the Φ3.92mm drawn TB14 wire are shown in Table 4. Table 4 shows that the various mechanical properties of the wire are consistent and stable.

[0062] Table 3. Dimensional Inspection Results of TB14 Wire in Φ3.92mm Drawing State

[0063] test points Test point 1 Test point 2 Test point 3 Test point 4 Test point 5 Test point 6 Test point 7 Size / mm Φ3.925 Φ3.928 Φ3.915 Φ3.918 Φ3.912 Φ3.911 Φ3.921 Roughness / μm 0.445 0.483 0.476 0.456 0.487 0.446 0.481

[0064] Table 4. Test results of mechanical properties of TB14 wire in drawn state with a diameter of Φ3.92mm.

[0065] test points Test point 1 Test point 2 Test point 3 Test point 4 Test point 5 Test point 6 Tensile strength / MPa 701 705 703 703 706 705 Yield strength / MPa 632 634 632 630 633 633 Elongation / % 13.3 13.2 13.6 14.5 14.1 13.9 Reduction of area / % 81 84 84 86 82 83

[0066] Example 3

[0067] A method for preparing TB14 titanium alloy wire for improving the surface accuracy and performance of fasteners includes the following steps:

[0068] S1: TB14 ingots with uniform composition and a Φ400mm specification are used for forging on a 2000t hydraulic press. The first forging process begins at 1150℃, holds for 3 hours, and ends at a final forging temperature >700℃, with a 70% deformation rate in upsetting and drawing. The second forging process begins at 1050℃, holds for 3 hours, and ends at a final forging temperature >600℃, with a 65% deformation rate in upsetting and drawing.

[0069] S2: After surface treatment, the titanium billet forged in step S1 is rolled using a reciprocating rolling mill. The first rolling pass is at a temperature of 900℃, held for 2 hours, with a rolling speed of 2 m / s, a final rolled size of Φ60 mm, 13 rolling passes, and a rolling deformation of 75%. The second rolling pass is at a temperature of 850℃, held for 2 hours, with 10 rolling passes, a final rolled size of Φ10 mm, and a rolling deformation of 97%.

[0070] S3: Perform a rounding and peeling process on the wire rod from step S2. Then, using a rotary forging mill, reduce the diameter of the Φ9.0mm wire to Φ5.5mm in 7 passes, with each pass reducing the diameter by 0.5mm. Hydraulic oil is used for lubrication during the rotary forging process. The wire feeding rate during rotary forging is no more than 0.5 / min, and no heat treatment is required during the rotary forging process.

[0071] S4: The intermediate filament obtained in step S3 undergoes vacuum annealing heat treatment at a temperature of 690–720℃ for 1–2 hours, using water cooling. A water-soluble lubricant is then evenly applied to the annealed filament, followed by roller drawing. The Φ5.5mm wire is reduced to Φ2.43mm in three passes using a continuous-drawing roller drawing machine, with a deformation rate of 80.4%.

[0072] The dimensional inspection results of the Φ2.43mm drawn TB14 wire prepared in this embodiment are shown in Table 5. Table 5 shows that the wire has high precision, with a tolerance within 0-0.02mm and a surface roughness Ra≤0.5μm. The mechanical property test results of the Φ3.92mm drawn TB14 wire are shown in Table 6. Table 6 shows that the various mechanical properties of the wire are consistent and stable.

[0073] Table 5. Dimensional Inspection Results of TB14 Wire in Φ2.43mm Drawing State

[0074] test points Test point 1 Test point 2 Test point 3 Test point 4 Test point 5 Test point 6 Test point 7 Size / mm Φ2.436 Φ2.438 Φ2.431 Φ2.436 Φ2.421 Φ2.427 Φ2.424 Roughness / μm 0.455 0.481 0.473 0.466 0.477 0.432 0.484

[0075] Table 6. Test results of mechanical properties of TB14 in drawn state with a diameter of Φ2.43mm.

[0076] test points Test point 1 Test point 2 Test point 3 Test point 4 Test point 5 Test point 6 Tensile strength / MPa 730 731 733 736 736 732 Yield strength / MPa 652 654 657 653 653 651 Elongation / % 12.2 12.3 11.5 11.8 11.6 12.3 Reduction of area / % 85 83 81 81 83 85

[0077] like Figures 1-6 As shown, the transverse and longitudinal microstructures of the typical drawn TB14 wire prepared by this invention can be seen. The wire has uniform and fine grains with a grain size of about 10, and obvious longitudinal flow lines.

[0078] like Figure 7 As shown, the surface condition of TB14 wire in a typical drawing state after upsetting is as follows. It can be seen that when the ratio of the height after forging to the height before forging is 1:5, there are no cracks on the sample surface.

[0079] 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 TB14 titanium alloy wire for improving the surface accuracy and performance of fasteners, characterized in that, Includes the following steps: S1. Forging: After removing the outer skin and riser from the TB14 ingot, a billet is obtained. The billet is then forged to obtain a titanium billet. The forging process uses a two-fire method. The first forging uses a three-upsetting and three-drawing method, and the second forging uses a two-upsetting and two-drawing method. The initial forging temperature of the first forging is 1050~1150℃, and it is held for 3 hours. The final forging temperature is >700℃, and the deformation amount of upsetting and drawing is 65~70%. The initial forging temperature of the second forging is 900~1000℃, and it is held for 3 hours. The final forging temperature is >600℃, and the deformation amount of upsetting and drawing is 60~65%. S2. Rolling: After polishing the surface of the titanium billet to a metallic luster and removing any visible defects, the titanium billet is rolled into wire rod. The rolling process is a two-stage rolling process. The first stage rolling process parameters are: temperature 850~900℃, holding time 2h, rolling speed 2m / s, final rolled size Φ60mm, 13 rolling passes, and rolling deformation 75%. The second stage rolling process parameters are: temperature 800~850℃, holding time 2h, 10 rolling passes, and final rolled size Φ10mm. S3. Rotary Forging: The wire rod undergoes a rounding-skinning process. Rounding is achieved by hot drawing at temperatures below 800℃ to remove surface defects, resulting in a diameter of Φ9.5mm. Skinning removes oxide scale and surface defects, resulting in a diameter of Φ9.0mm, yielding wire. Rotary forging is then performed to obtain intermediate wire. The rotary forging process involves 7 passes, with each pass reducing the diameter by 0.5mm, reducing the diameter of the Φ9.0mm wire to Φ5.5mm. Hydraulic oil is used for lubrication during the rotary forging process, and no heat treatment is required. S4. Roller drawing: After vacuum annealing heat treatment, the intermediate filament is drawn using a roller die to obtain the filament product. No heat treatment is required during the roller drawing process. The vacuum annealing heat treatment temperature is 700℃~810℃, the holding time is 1h~2h, and water cooling is used. Before roller drawing, a water-soluble lubricant needs to be evenly applied to the intermediate filament. During the roller drawing process, the diameter of the intermediate filament is reduced to Φ4.3-Φ4.9mm, Φ3.5-Φ3.9mm, Φ2.0-Φ2.4mm, or Φ1.8-2.0mm.

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