Preparation method of low-gap TC4ELI titanium alloy wire

Abstract

The invention relates to the technical field of wire material preparation, and particularly discloses a preparation method of a low-gap TC4ELI titanium alloy wire material, which comprises the following steps: S100, preparing a TC4ELI titanium alloy wire rod through the working procedures of smelting, forging and rolling; s200, the wire rod is subjected to rounding-peeling-polishing procedure treatment, and a coiled wire with the bright surface is obtained; s300, the coiled wire is subjected to multi-pass roller die drawing treatment, and a drawn wire material is obtained; s400, carrying out one-time online heat treatment on the drawn wire to obtain a completely annealed wire; s500, the step S300 and the step S400 are repeatedly executed for multiple times, and the wire of the finished product specification is obtained; and S600, the wire with the finished product specification is subjected to dehydrogenation and homogenization heat treatment, and the finished wire is obtained. According to the method, the machining efficiency is greatly improved, the machining cost is reduced, overburnt structures can be eliminated, and the wire quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wire preparation, and particularly to a method for preparing a low-gap TC4ELI titanium alloy wire. Background Art

[0002] TC4ELI is a medium-strength titanium alloy developed on the basis of Ti-6Al-4V titanium alloy by strictly controlling the content of interstitial elements such as carbon, hydrogen, oxygen, and nitrogen and reducing the content of impurity elements. In engineering practice, the O and Fe elements in the alloy are mainly controlled, and their contents are O≤0.13% and Fe≤0.25%. The O and Fe elements are the impurity elements that are mainly concerned in titanium alloys. O belongs to α-stable elements, and Fe belongs to β-stable elements, and both of them can effectively fine-tune the alloy strength. The application fields of TC4ELI titanium alloy are very extensive, covering many aspects from aerospace, ship and ocean engineering to medical devices.

[0003] Although the alloy strength of low-gap TC4ELI is lower than that of ordinary TC4, in the process of preparing TC4ELI titanium alloy wire, due to its high strength, the processing process is cumbersome, the processing efficiency is low, and the processing cost remains high. Moreover, due to its long hot processing process, the TC4ELI titanium alloy wire is prone to overburned structure in the core position, that is, there are coarse lath-like β transformation structures, which will seriously reduce the plasticity and fatigue performance of the material.

[0004] Therefore, how to produce high-quality TC4ELI titanium alloy wire has become a technical problem to be solved urgently in the field of wire preparation. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the main purpose of the present invention is to provide a method for preparing a high-quality low-gap TC4ELI titanium alloy wire. The method sequentially forges and hot-rolls the ingot after melting, and then combines the roller die drawing process to further improve the uniformity and stability of the wire, and prepares the TC4ELI titanium alloy wire.

[0006] In order to solve at least one of the above technical problems, the present invention adopts the following technical solutions: According to the present invention, a method for preparing a low-gap TC4ELI titanium alloy wire is provided, including the following steps: S100, preparing a TC4ELI titanium alloy wire rod through melting, forging, and rolling processes; S200, subjecting the wire rod to a roundness-removing - peeling - polishing process to obtain a wire with a bright surface; S300, subjecting the wire to multi-pass roller die drawing to obtain a drawn wire; S400, subjecting the drawn wire to one-time online heat treatment to obtain a fully annealed wire; S500, repeatedly performing steps S300 and S400 multiple times to obtain a wire of the finished product specification; S600, subjecting the wire of the finished product specification to dehydrogenation + homogenization heat treatment to obtain the finished wire.

[0007] According to an embodiment of the present invention, in step S100, a TC4ELI ingot is obtained by three times of vacuum consumable melting, and a TC4ELI titanium alloy wire rod with a diameter of Φ8.5 mm is obtained through forging and rolling.

[0008] According to an embodiment of the present invention, in step S100, the TC4ELI titanium alloy wire rod is composed of chemical components with the following weight percentages: Al: 5.5 wt% - 5.8 wt%, V: 3.8 wt% - 4.2 wt%, Fe ≤ 0.05 wt%, C ≤ 0.02 wt%, H ≤ 0.001 wt%, O ≤ 0.05 wt%, N ≤ 0.03 wt%, Si ≤ 0.01 wt%, and the balance is Ti and unavoidable impurities.

[0009] According to an embodiment of the present invention, step S200 includes: S210, subjecting the titanium alloy wire rod to rotary forging at room temperature by means of rotary forging, wherein the rotary forging speed is controlled to be 5 - 10 m / min, the rotary forging deformation amount is 10% - 12%, and the lubricant is industrial lubricating oil; S220, peeling the rotary-forged wire rod by means of turning, wherein the main shaft speed is controlled to be 1000 - 1200 r / min, the peeling speed is 5 - 7 m / min, the linear speed is 28 - 30 m / min, and the peeling amount is 0.4 - 0.6 mm; S230, polishing the peeled wire rod by means of a sand belt polishing machine to obtain a wire with a bright surface, wherein the sand belt mesh number is selected as 240 mesh, 320 mesh, and 480 mesh, the polishing speed is controlled to be 5 - 7 m / min, the polishing frequency is 20 - 25 Hz, and the polishing amount is 0.01 - 0.02 mm.

[0010] According to an embodiment of the present invention, in step S300, the drawing equipment is a six-pass cold drawing machine, and six groups of dies can be installed simultaneously for drawing; the wheel type of the roller die is a two-roller symmetric structure, which is composed of five groups of roller wheels; each time the diameter is reduced by roller die cold drawing, the die is replaced with a die matching the target size of the wire.

[0011] According to an embodiment of the present invention, in step S300, the accuracy of the outlet of each pass is controlled within ±0.02 mm, the drawing speed is 90 - 150 m / min, the deformation amount per single pass of drawing is 10% - 15%, and after every 5 - 6 cumulative diameter reductions of the bright wire rod, annealing treatment is carried out, and the cumulative deformation amount is controlled to be 60% - 70% to obtain the drawn wire material.

[0012] According to an embodiment of the present invention, in step S300, water-soluble lubricant is used for lubrication.

[0013] According to an embodiment of the present invention, in step S400, the drawn wire material is ultrasonically cleaned online before the first online heat treatment. During the cleaning process, the ultrasonic frequency is controlled to be 80 - 100 kHz, and the traveling speed is 5 - 10 m / min.

[0014] According to an embodiment of the present invention, in steps S400 and S600, the protective gas during the first online heat treatment is 99.999% high-purity argon, the argon flow rate is 15 - 20 L / min, the heat treatment temperature of the first online heat treatment is controlled to be 850 °C, the heat preservation time is 10 - 30 min, the traveling speed of the wire material is 5 - 10 m / min, and the cooling method is argon gas blowing cooling.

[0015] According to an embodiment of the present invention, in step S600, the dehydrogenation + homogenization heat treatment includes: S610, performing vacuum heat treatment, controlling the heat treatment temperature of the vacuum heat treatment to be 800 - 850 °C, the heat preservation time to be 2 h - 3 h, and filling 99.999% high-purity argon for cooling when the temperature drops to 400 °C; S620, performing the second online heat treatment, the protective gas during the second online heat treatment is 99.999% high-purity argon, the argon flow rate is 15 - 20 L / min, controlling the heat treatment temperature of the second online heat treatment to be 850 °C, the heat preservation time to be 10 - 30 min, the traveling speed of the wire material is 5 - 10 m / min, and the cooling method is argon gas blowing cooling.

[0016] By adopting the above technical solutions, the present invention has at least one of the following advantages compared with the prior art: (1) Starting from the composition design, the present invention controls the contents of Al, O, and Fe elements to regulate the properties of the wire material products, enabling it to maintain high plasticity on the basis of high strength. This can not only improve the strength and toughness of the wire material but also reduce its deformation resistance, providing strong support for the subsequent large deformation amount diameter reduction of the wire material.

[0017] (2) The present invention uses five groups of two-roll symmetric structure roll dies for cold drawing. Compared with the conventional two groups of three-roll symmetric structure roll dies, it has a higher single-pass deformation amount, deformation uniformity, and deformation smoothness. The large deformation amount of this roll die can fully break the overburned structure inside the wire rod, improve the tissue performance, and increase the product qualification rate. At the same time, this roll die can perform multi-pass drawing simultaneously, which can not only reduce the threading time, but also the large deformation amount can increase the total deformation amount, reduce the number of heat treatment times, improve the production efficiency, and reduce the production cost to 30% of the original cost.

[0018] (3) The on-line heat treatment equipment adopted by the present invention can realize the on-line treatment of the whole process of cleaning - drying - heat treatment - solution compared with the conventional equipment. Integrating multiple processes into one can greatly improve the production efficiency. At the same time, on-line heat treatment and vacuum heat treatment can improve the tissue uniformity and consistency of the wire rod, and avoid the influence of different coil weights of off-line heat treatment on the uniform heating.

[0019] (4) In addition, the on-line heat treatment process can ensure that a large amount of drawn wire rods with stored distortion energy generate a large number of nucleation sites during recrystallization, so as to achieve the purpose of refining the grains and eliminating the coarse overburned structure.

[0020] (5) Other features and advantages of the present invention will be described in the subsequent specification, and some of them will be obvious from the specification, or understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structure pointed out in the specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 Schematic diagram of the steps of the preparation method of low-clearance TC4ELI titanium alloy wire according to an embodiment of the present invention; Figure 2 Microstructure diagram of the overburned core of the TC4ELI titanium alloy wire rod with a Φ8.5mm specification in an embodiment of the present invention; Figure 3 Microstructure diagram of the core of the TC4ELI titanium alloy wire with a Φ3.0mm specification in an embodiment of the present invention; Figure 4 Microstructure diagram of the core of the TC4ELI titanium alloy wire with a Φ2.0mm specification in an embodiment of the present invention; Figure 5 Shows the microstructure diagram of the core of a Φ1.6mm - sized TC4ELI titanium alloy wire in an embodiment of the present invention; Figure 6 Shows the microstructure diagram of the core of a Φ3.0mm - sized TC4ELI titanium alloy wire in the comparative example of the present invention. Specific embodiments

[0023] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the following further details the embodiments of the present invention in conjunction with specific embodiments and with reference to the accompanying drawings.

[0024] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments of the present invention are described in detail, those skilled in the art can easily appreciate that various modifications are feasible without substantially departing from the teachings of the subject matter of the present invention. Accordingly, all such modifications should be included within the scope of the present invention. Without departing from the gist of the present invention, other substitutions, modifications, changes, and deletions can be made to the design, operating conditions, parameters, etc. of the following exemplary embodiments.

[0025] The present invention provides a method for preparing a low - interstitial TC4ELI titanium alloy wire. As Figure 1 shown, the method generally includes the following steps: S100, preparing a TC4ELI titanium alloy wire rod through melting, forging, and rolling processes; S200, performing a round - straightening - peeling - polishing process on the wire rod to obtain a wire with a bright surface; S300, performing multi - pass roller - die drawing on the wire to obtain a drawn - state wire; S400, performing an on - line heat treatment on the drawn - state wire once to obtain a fully annealed wire; S500, repeatedly executing step S300 and step S400 multiple times to obtain a wire of the finished product specification; S600, performing dehydrogenation + homogenization heat treatment on the wire of the finished product specification to obtain the finished wire.

[0026] Step S100 can obtain a TC4ELI ingot by three times of vacuum consumable melting, and obtain a TC4ELI titanium alloy wire rod with a diameter of Φ8.5 mm through forging and rolling. Preferably, when designing the composition, control the contents of Al, O and Fe elements to improve the plasticity and fatigue performance of the TC4ELI titanium alloy wire. In the embodiments of the present invention, the TC4ELI titanium alloy wire rod is composed of chemical components with the following weight percentages: Al: 5.5 wt% - 5.8 wt%, V: 3.8 wt% - 4.2 wt%, Fe ≤ 0.05 wt%, C ≤ 0.02 wt%, H ≤ 0.001 wt%, O ≤ 0.05 wt%, N ≤ 0.03 wt%, Si ≤ 0.01 wt%, and the balance is Ti and unavoidable impurities. In other embodiments, those skilled in the art can appropriately change the values of each element by using the teaching content disclosed herein to seek the required characteristics. It should be understood that the use of a numerical range represented by endpoints includes all numbers within the range and any range within the range. Taking Al as an example, 5.5 wt% - 5.8 wt% may include 5.5 wt%, 5.6 wt%, 5.7 wt%, 5.8 wt%, etc.

[0027] In order to prove that the cold drawing wire manufacturing process plan can eliminate the overburned structure in the titanium wire rod, a Φ8.5 mm TC4ELI titanium alloy wire rod is selected, and its structure is as shown in the appendix Figure 2 shown, which is an equiaxed structure in the α + β two-phase region, where the β grains are fully fragmented, the average α grain size is 5 - 10 μm, and there is a small amount of overburned structure at the core position, that is, there are coarse lath-like β transformation structures.

[0028] In step S200, the wire rod is subjected to the processes of rounding - skinning - polishing, which specifically may include: S210, subject the titanium alloy wire rod to rotary forging at room temperature by means of rotary forging, wherein control the rotary forging speed to be 5 - 10 m / min, the rotary forging deformation amount to be 10% - 12%, and the lubricant to be industrial lubricating oil; S220, skin the rotary forged wire rod by means of turning, wherein control the spindle speed to be 1000 - 1200 r / min, the skinning speed to be 5 - 7 m / min, the linear speed to be 28 - 30 m / min, and the skinning amount to be 0.4 - 0.6 mm; S230, polish the skinned wire rod by means of a sand belt polishing machine to obtain a wire with a bright surface, wherein select the sand belt mesh number to be 240 mesh, 320 mesh, 480 mesh, control the polishing speed to be 5 - 7 m / min, the polishing frequency to be 20 - 25 Hz, and the polishing amount to be 0.01 - 0.02 mm.

[0029] In an embodiment of the present invention, the size of the titanium alloy wire rod after rotary forging is Φ8.0mm ± 0.05mm, and the size after skinning is Φ7.5mm ± 0.05mm.

[0030] In step S300, specifically, the wire drawing equipment used for wire drawing can be a six-pass cold drawing machine, which can install six groups of dies for wire drawing at the same time; the wheel shape of the roller die is a two-roller symmetric structure and is composed of five groups of roller wheels; each time the diameter is reduced by cold drawing with the roller die, the die is replaced with a die matching the target size of the wire material. It is preferably controlled that the accuracy of the outlet of each pass is within ±0.02mm, the wire drawing speed is 90 - 150m / min, the single-pass deformation amount of wire drawing is 10% - 15%, and the bright wire is annealed after every 5 - 6 times of cumulative diameter reduction, and the cumulative deformation amount is controlled to be 60% - 70% to obtain the wire material in the drawn state. Water-soluble lubricant is used to ensure the lubrication quality during wire drawing.

[0031] In step S400, the wire material in the drawn state is ultrasonically cleaned online before the first online heat treatment. During the cleaning process, the ultrasonic frequency is controlled to be 80 - 100kHz, and the traveling speed is 5 - 10m / min. The cleaned wire material is subjected to continuous online heat treatment in a 20-meter-long furnace tube. The protective gas during heating is 99.999% high-purity argon, the argon flow rate is 15 - 20L / min, the heating temperature is 850°C, the holding time is 10 - 30min, the traveling speed of the wire material is 5 - 10m / min, and the cooling method is fast cooling by argon gas blowing.

[0032] In step S500, the wire material prepared in S400 is continuously repeated in steps S300 and S400, and finally the wire rod with a diameter of Φ8.5mm is drawn to Φ3.0 - Φ1.6mm to obtain the wire material of the finished product specification.

[0033] In step S600, the dehydrogenation + homogenization heat treatment includes: S610, perform vacuum heat treatment, control the heat treatment temperature of the vacuum heat treatment to be 800 - 850°C, the holding time to be 2h - 3h, and fill 99.999% high-purity argon for cooling when the temperature drops to 400°C; S620, perform secondary online heat treatment. The protective gas during the secondary online heat treatment is 99.999% high-purity argon, the argon flow rate is 15 - 20L / min, control the heat treatment temperature of the secondary online heat treatment to be 850°C, the holding time to be 10 - 30min, the traveling speed of the wire material to be 5 - 10m / min, and the cooling method is cooling by argon gas blowing.

[0034] The method according to the present invention starts from the composition design, adjusts the material properties by controlling the alloy element content, and simultaneously prepares TC4ELI titanium alloy wire by means of roller die cold drawing, so as to solve the problems existing in the existing TC4ELI titanium alloy wire, improve the production efficiency and product rate of TC4ELI titanium alloy wire, and meet the market requirements for TC4ELI titanium alloy wire.

[0035] The following are specific embodiments and specific process parameters of the low-interstitial TC4ELI titanium alloy wire and its preparation method according to the present invention.

[0036] Example 1 Use a TC4ELI titanium alloy coil with a diameter of Φ8.5mm to prepare a TC4ELI titanium alloy wire with a diameter of Φ3.0mm.

[0037] Step S100: The components of the selected TC4ELI titanium alloy coil are as follows: Al: 5.6wt%, V: 3.9wt%, Fe: 0.02wt%, C: 0.015wt%, H: 0.0025wt%, O: 0.045wt%, N: 0.005wt%, S: 0.005wt%, and the balance is Ti and unavoidable impurities. The microstructure is mainly equiaxed structure in the α+β two-phase region, in which the β grains are fully fragmented, and the average α grain size is 5-10μm. In step S100, select a coil with a small amount of overburned structure at the core position, that is, there is a coarse lath-like β transformation structure at the core position.

[0038] Step S200: Perform rotary swaging - peeling - polishing operations on the coil in step S100. Specifically, Step S210: Perform rotary swaging on the titanium alloy coil at room temperature by means of rotary swaging, the rotary swaging speed is 5m / min, the rotary swaging deformation amount is 10%, the lubricant is industrial lubricating oil, and the size after rotary swaging is Φ8.0mm±0.05mm; Step S220: Peeling the rotary swaged coil by means of turning, the turning speed of the turning tool is 1000r / min, the peeling speed is 5m / min, the linear speed is 28m / min, the peeling amount is 0.4mm, and the size after peeling is Φ7.6mm±0.05mm; Step S230: Polish the peeled coil by means of a sand belt polishing machine, the sand belt mesh number is 240 mesh and 320 mesh, the polishing speed is 5m / min, the polishing frequency is 20Hz, and the polishing amount is 0.01mm.

[0039] Step S300: Uniformly apply a water-soluble lubricant on the bright wire obtained in step S200, and then perform roller die drawing. Use a six-pass continuous roller die drawing machine to draw the Φ7.6mm bright wire for 5 passes to Φ4.6mm, and the drawing speed is 110m / min.

[0040] Step S400: Continuously perform on-line heat treatment on the drawn wire in a protective atmosphere. The drawn wire is first subjected to on-line ultrasonic cleaning and then on-line heat treatment. The ultrasonic frequency during cleaning is 80 kHz, the traveling speed is 6 m / min, and the cleaning medium is a weakly alkaline cleaning agent. The protective gas during heating is 99.999% high-purity argon with an argon flow rate of 15 L / min, the heating temperature is 850 °C, the holding time is 20 min, the traveling speed of the wire is 6 m / min, and the cooling method is fast cooling by argon gas blowing.

[0041] Step S500: Repeat Step S300 and Step S400 for the wire prepared in Step S400, and draw 5 passes to draw the Φ4.6 mm wire to Φ3.0 mm.

[0042] Step S600: Perform dehydrogenation + homogenization heat treatment on the Φ3.0 mm drawn wire prepared in Step S500. Specifically, Step S610: First perform vacuum heat treatment. The heating temperature is 800 °C, the holding time is 2 h, and when the temperature is lowered to 400 °C, it is quickly cooled by filling 99.999% high-purity argon; Step S620: Then perform on-line heat treatment. The protective gas during heating is 99.999% high-purity argon with an argon flow rate of 15 L / min, the heating temperature is 800 °C, the holding time is 5 min, the traveling speed of the wire is 10 m / min, and the cooling method is fast cooling by argon gas blowing.

[0043] Perform microstructure observation on the Φ3.0 mm specification TC4ELI wire prepared in this embodiment. The microstructure results are as Figure 3 shown. The core structure has been fully broken and refined, the overburned structure has disappeared, and the grains are uniform and fine. Perform mechanical property testing on the Φ3.0 mm specification TC4ELI wire prepared. Select 6 test points (separately selected) on the prepared TC4ELI wire and perform tensile strength, yield strength, elongation, and reduction of area testing respectively. The results are shown in Table 1. It can be seen from Table 1 that the mechanical properties of the wire are consistent and stable.

[0044] Table 1 Mechanical Property Testing Results of Φ3.0 mm Specification Annealed TC4ELI Wire

[0045] Example 2 Use a Φ8.5 mm TC4ELI titanium alloy wire rod to prepare a Φ2.0 mm TC4ELI titanium alloy wire.

[0046] Step S100: The composition of the selected TC4ELI titanium alloy wire rod is as follows: Al: 5.7 wt%, V: 4.0 wt%, Fe: 0.015 wt%, C: 0.017 wt%, H: 0.0020 wt%, O: 0.040 wt%, N: 0.004 wt%, S: 0.006 wt%, and the balance is Ti and unavoidable impurities. The microstructure is mainly equiaxed structure in the α+β two-phase region, where the β grains are fully fragmented, and the average α grain size is 5-10 μm. In step S100, select the wire rod with a small amount of overburned structure at the core position, that is, there is coarse lath-like β transformation structure at the core position.

[0047] Step S200: Perform rotary forging - skinning - polishing process on the wire rod in step 2. Specifically, Step S210: Perform rotary forging on the titanium alloy wire rod at room temperature by rotary forging method. The rotary forging speed is 8 m / min, the rotary forging deformation amount is 11%, the lubricant is industrial lubricating oil, and the size after rotary forging is Φ8.0 mm ± 0.05 mm; Step S220: Skin the rotary-forged wire rod by turning method. The turning speed of the turning tool is 1050 r / min, the skinning speed is 8 m / min, the linear speed is 28.5 m / min, the skinning amount is 0.5 mm, and the size after skinning is Φ7.5 mm ± 0.05 mm; Step S230: Polish the skinned wire rod with a sand belt polishing machine. The sand belt mesh number is 320 mesh and 480 mesh, the polishing speed is 8 m / min, the polishing frequency is 23 Hz, and the polishing amount is 0.01 mm.

[0048] Step S300: Uniformly apply a water-soluble lubricant on the bright wire obtained in step S200, and then perform roller die drawing. Use a six-pass continuous roller die drawing machine to draw the Φ7.5 mm bright wire 5 passes to Φ4.6 mm, and the drawing speed is 90 m / min.

[0049] Step S400: Perform protective atmosphere continuous online heat treatment on the drawn wire obtained in step S300. The drawn wire is first subjected to online ultrasonic cleaning and then online heat treatment. The ultrasonic frequency during cleaning is 90 kHz, the traveling speed is 8 m / min, and the cleaning medium is a weakly alkaline cleaning agent. The protective gas during heating is 99.999% high-purity argon, the argon flow rate is 17 L / min, the heating temperature is 850 °C, the holding time is 19 min, the wire traveling speed is 8 m / min, and the cooling method is fast cooling by argon gas blowing.

[0050] Step S500: Repeat step S300 for the wire prepared in step S400 for 5 passes of drawing to draw the Φ4.6mm wire to Φ3.0mm. Then, after repeating step S400, when the annealed wire is obtained, repeat step S300 for 3 passes of drawing to draw the Φ2.8mm wire to Φ2.0mm.

[0051] Step S600: Perform dehydrogenation + homogenization heat treatment on the Φ2.0mm drawn wire prepared in step S500. Specifically, Step S610: First, perform vacuum heat treatment. The heating temperature is 820°C, the holding time is 2.5h, and when the temperature is cooled to 400°C, fill with 99.999% high-purity argon gas for rapid cooling; Step S620: Then, perform online heat treatment. The protective gas during heating is 99.999% high-purity argon gas, the argon gas flow rate is 15L / min, the heating temperature is 820°C, the holding time is 4min, the wire traveling speed is 12m / min, and the cooling method is rapid cooling by argon gas blowing.

[0052] Perform microscopic structure observation on the Φ2.0mm specification TC4ELI wire prepared in this embodiment. The microscopic structure results are as Figure 4 shown. The core structure has been fully broken and refined, the overburned structure has disappeared, and the grains are uniform and fine. Perform mechanical property testing on the Φ2.0mm specification TC4ELI wire prepared. Select 6 test points (separately selected) on the prepared TC4ELI wire, and perform tensile strength, yield strength, elongation, and reduction of area tests respectively. The results are shown in Table 2. It can be seen from Table 2 that the mechanical properties of the wire are consistent and stable.

[0053] Table 2 Mechanical Property Testing Results of Φ2.0mm Specification TC4ELI Wire

[0054] Example 3 Use a Φ8.5mm TC4ELI titanium alloy wire rod to prepare a Φ1.6mm TC4ELI titanium alloy wire.

[0055] Step S100: The composition of the selected TC4ELI titanium alloy wire rod is as follows: Al: 5.8 wt%, V: 4.2 wt%, Fe: 0.010 wt%, C: 0.016 wt%, H: 0.0023 wt%, O: 0.042 wt%, N: 0.003 wt%, S: 0.004 wt%, and the balance is Ti and unavoidable impurities. The microstructure is mainly equiaxed structure in the α+β two-phase region, where the β grains are fully fragmented, and the average α grain size is 5-10 μm. In step S100, select the wire rod with a small amount of overburned structure at the core position, that is, there are thick plate-like β transformation structures at the core position.

[0056] Step S200: Perform rotary swaging - skinning - polishing operations on the wire rod in step 2. Specifically, Step S210: Perform rotary swaging on the titanium alloy wire rod at room temperature by rotary swaging. The rotary swaging speed is 10 m / min, the rotary swaging deformation is 12%, the lubricant is industrial lubricating oil, and the size after rotary swaging is Φ8.0 mm ± 0.05 mm; Step S220: Skin the rotary swaged wire rod by turning. The turning speed of the turning tool is 1200 r / min, the skinning speed is 5 m / min, the linear speed is 25 m / min, the skinning amount is 0.5 mm, and the size after skinning is Φ7.5 mm ± 0.05 mm; Step S230: Polish the skinned wire rod with a belt-type polishing machine. The belt mesh number is 320 mesh and 480 mesh, the polishing speed is 10 m / min, the polishing frequency is 25 Hz, and the polishing amount is 0.01 mm.

[0057] Step S300: Uniformly apply a water-soluble lubricant on the bright wire obtained in step S200, and then perform roller die drawing. Use a six-pass continuous roller die drawing machine to draw the Φ7.5 mm bright wire 5 passes to Φ4.6 mm, and the drawing speed is 120 m / min.

[0058] Step S400: Perform protective atmosphere continuous online heat treatment on the drawn wire obtained in step S300. The drawn wire is first subjected to online ultrasonic cleaning and then online heat treatment. The ultrasonic frequency during cleaning is 100 kHz, the traveling speed is 10 m / min, and the cleaning medium is a weakly alkaline cleaning agent. The protective gas during heating is 99.999% high-purity argon, the argon flow rate is 15 L / min, the heating temperature is 850 °C, the holding time is 15 min, the wire traveling speed is 10 m / min, and the cooling method is rapid cooling by argon gas blowing.

[0059] Step S500: Repeat step S300 for the wire prepared in step S400, draw it for 6 passes, draw the Φ4.6mm wire to Φ2.8mm, then repeat step S400, and after obtaining the annealed wire, repeat step S300 again, draw it for 6 passes, and draw the Φ2.8mm wire to Φ1.6mm.

[0060] Step S600: Perform dehydrogenation + homogenization heat treatment on the Φ1.6mm drawn wire prepared in step S500. Specifically, Step S610: First, perform vacuum heat treatment, with a heating temperature of 850°C, a holding time of 3h, and quickly cool it by filling 99.999% high-purity argon gas when the temperature drops to 400°C; Step S620: Then, perform on-line heat treatment. The protective gas during heating is 99.999% high-purity argon gas, the argon gas flow rate is 15L / min, the heating temperature is 850°C, the holding time is 3min, the wire traveling speed is 15m / min, and the cooling method is to quickly cool it by blowing with argon gas.

[0061] Perform microstructure observation on the Φ1.6mm specification TC4ELI wire prepared in this embodiment. The microstructure results are as Figure 5 shown. Its internal organizational structure is uniform and stable, and the grains of the wire are uniform. Perform mechanical property testing on the Φ1.6mm specification TC4ELI wire prepared. Select 6 test points (the 6 test points are selected separately) on the prepared TC4ELI wire, and perform tensile strength, yield strength, elongation rate, and reduction of area testing respectively. The results are shown in Table 3. It can be seen from Table 3 that the mechanical properties of the wire are consistent and stable.

[0062] Table 3 Detection Results of Mechanical Properties of Φ1.60mm Specification TC4ELI

[0063] It can be seen from the above embodiments that the TC4ELI wire prepared by the present invention has a simplified process, a large amount of deformation, high production efficiency, and the core structure of the wire has been fully broken and refined, the overburned structure has disappeared, and the grains are uniform and fine.

[0064] Comparative Example 1 Prepare Φ3.0mm TC4ELI titanium alloy wire by cold drawing. The preparation process is the same as that of Example 1, except that the TC4ELI titanium alloy coil selected in step S100 has a conventional composition.

[0065] Step S100: The composition of the selected TC4ELI titanium alloy wire rod is as follows: Al: 6.2 wt%, V: 3.9 wt%, Fe: 0.1 wt%, C: 0.015 wt%, H: 0.0025 wt%, O: 0.01 wt%, N: 0.005 wt%, S: 0.005 wt%, and the balance is Ti and unavoidable impurities. The microstructure is mainly equiaxed structure in the α+β two-phase region, where the β grains are fully fragmented, and the average α grain size is 5-10 μm. In step S100, select the wire rod with a small amount of overburned structure at the core position, that is, there is coarse lath-like β transformation structure at the core position.

[0066] Step S200: Perform rotary swaging - skinning - polishing operations on the wire rod in step 2. Specifically, Step S210: Perform rotary swaging on the titanium alloy wire rod at room temperature in a rotary swaging manner. The rotary swaging speed is 5 m / min, the rotary swaging deformation is 10%, the lubricant is industrial lubricating oil, and the size after rotary swaging is Φ8.0 mm ± 0.05 mm; Step S220: Skin the rotary swaged wire rod by turning. The turning speed of the turning tool is 1000 r / min, the skinning speed is 5 m / min, the linear speed is 28 m / min, the skinning amount is 0.4 mm, and the size after skinning is Φ7.6 mm ± 0.05 mm; Step S230: Polish the skinned wire rod with a belt sander. The belt mesh number is 240 mesh and 320 mesh, the polishing speed is 5 m / min, the polishing frequency is 20 Hz, and the polishing amount is 0.01 mm.

[0067] Step S300: Uniformly apply a water-soluble lubricant on the bright wire obtained in step S200, and then perform roller die drawing. Use a six-pass continuous roller die drawing machine to draw the Φ7.6 mm bright wire 3 passes to Φ6.0 mm, and the drawing speed is 50 m / min.

[0068] Step S400: Perform protective atmosphere continuous online heat treatment on the drawn wire obtained in step S300. The drawn wire is first subjected to online ultrasonic cleaning and then online heat treatment. The ultrasonic frequency during cleaning is 80 kHz, the traveling speed is 6 m / min, and the cleaning medium is a weakly alkaline cleaning agent. The protective gas during heating is 99.999% high-purity argon, the argon flow rate is 15 L / min, the heating temperature is 850 °C, the holding time is 20 min, the wire traveling speed is 6 m / min, and the cooling method is fast cooling by argon gas blowing.

[0069] Step S500: Repeat step S300 for the wire prepared in step S400 for 3 drawing passes to draw the Φ6.0 mm wire to Φ4.6 mm. Then, after repeating step S400, when the annealed wire is obtained, repeat step S300 for 3 drawing passes to draw the Φ4.6 mm wire to Φ3.8 mm. Finally, after repeating step S400, when the annealed wire is obtained, repeat step S300 for 3 drawing passes to draw the Φ3.8 mm wire to Φ3.0 mm.

[0070] Step S600: Perform dehydrogenation + homogenization heat treatment on the Φ3.0 mm drawn wire prepared in step S500. Specifically, Step S610: First, perform vacuum heat treatment. The heating temperature is 800 °C, the holding time is 2 h, and when the temperature is cooled to 400 °C, 99.999% high-purity argon is filled for rapid cooling. Step S620: Then, perform online heat treatment. The protective gas during heating is 99.999% high-purity argon, the argon flow rate is 15 L / min, the heating temperature is 800 °C, the holding time is 5 min, the wire traveling speed is 10 m / min, and the cooling method is rapid cooling by argon gas blowing.

[0071] Microstructure observation was carried out on the Φ3.0 mm specification TC4ELI wire prepared in this comparative example. The microstructure results are as Figure 6 shown. Coarse lath-like β tissue still exists in the core tissue, and the overburned tissue inherited from the wire rod cannot be eliminated. Mechanical property tests were carried out on the Φ3.0 mm specification TC4ELI wire prepared. Six test points (separately selected) were selected from the prepared TC4ELI wire, and tensile strength, yield strength, elongation, and reduction of area were detected respectively. The results are shown in Table 4. It can be seen from Table 4 that the tensile strength of the wire increases and the elongation decreases, and the comprehensive mechanical properties of the wire become worse.

[0072] Table 4 Mechanical property test results of Φ3.0 mm specification annealed TC4ELI wire

[0073] The above are only the preferred embodiments of the present invention and are not used to limit the scope of implementation of the present invention; if the present invention is modified or equivalently replaced without departing from the spirit and scope of the present invention, it should be covered within the protection scope of the present invention.

[0074] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other variations in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present invention shall be included within the protection scope of the embodiments of the present invention.

Claims

1. A preparation method of a low-gap TC4ELI titanium alloy wire, characterized in that, It includes the following steps: S100, preparing a TC4ELI titanium alloy wire rod through smelting, forging, and rolling processes; S200, subjecting the wire rod to a roundness - peeling - polishing process to obtain a wire with a bright surface; S300, subjecting the wire to multi - pass roller die drawing to obtain a drawn wire; S400, subjecting the drawn wire to an on - line heat treatment once to obtain a fully annealed wire; S500, repeatedly executing step S300 and step S400 multiple times to obtain a wire of the finished product specification; S600, subjecting the wire of the finished product specification to dehydrogenation + homogenization heat treatment to obtain the finished wire.

2. The method according to claim 1, characterized in that, In step S100, a TC4ELI ingot is obtained by three - time vacuum consumable electrode melting, and a TC4ELI titanium alloy wire rod with a diameter of Φ8.5 mm is obtained through forging and rolling.

3. The method according to claim 2, characterized in that In step S100, the TC4ELI titanium alloy wire rod is composed of chemical components with the following weight percentages: Al: 5.5 wt% - 5.8 wt%, V: 3.8 wt% - 4.2 wt%, Fe ≤ 0.05 wt%, C ≤ 0.02 wt%, H ≤ 0.001 wt%, O ≤ 0.05 wt%, N ≤ 0.03 wt%, Si ≤ 0.01 wt%, and the balance is Ti and unavoidable impurities.

4. The method according to claim 1, wherein Step S200 includes: S210, subjecting the titanium alloy wire rod to rotary forging at room temperature by means of rotary forging. Among them, the rotary forging speed is controlled at 5 - 10 m / min, the rotary forging deformation amount is 10% - 12%, and the lubricant is industrial lubricating oil; S220, peeling the rotary - forged wire rod by turning. Among them, the main shaft speed is controlled at 1000 - 1200 r / min, the peeling speed is 5 - 7 m / min, the linear speed is 28 - 30 m / min, and the peeling amount is 0.4 - 0.6 mm; S230, polishing the peeled wire rod with a belt - type polishing machine to obtain a wire with a bright surface. Among them, the belt mesh number is selected as 240 mesh, 320 mesh, and 480 mesh, the polishing speed is controlled at 5 - 7 m / min, the polishing frequency is 20 - 25 Hz, and the polishing amount is 0.01 - 0.02 mm.

5. The method according to claim 1, characterized in that, In step S300, The drawing equipment is a six - pass cold drawing machine, and six groups of dies are installed for drawing; The wheel type of the roller die is a two - roll symmetric structure and is composed of five groups of roller wheels; Each time the diameter is reduced during roller die cold drawing, the die is replaced with a die matching the target size of the wire.

6. The method according to claim 5, wherein In step S300, the accuracy of the outlet of each pass is controlled within ±0.02 mm, the drawing speed is 90 - 150 m / min, the single - pass deformation amount of drawing is 10% - 15%, and the bright wire is annealed after every 5 - 6 cumulative diameter reductions. The cumulative deformation amount is controlled at 60% - 70% to obtain the drawn wire.

7. The method according to claim 6, characterized in that, In step S300, a water - soluble lubricant is used for lubrication.

8. The method according to claim 1, wherein In step S400, before the drawn wire is subjected to an on - line heat treatment once, it is cleaned by on - line ultrasonic cleaning. During the cleaning process, the ultrasonic frequency is controlled at 80 - 100 kHz, and the traveling speed is 5 - 10 m / min.

9. The method according to claim 1, characterized in that, In steps S400 and S600, the protective gas during the primary on-line heat treatment is 99.999% high-purity argon, the argon flow rate is 15 - 20 L / min, the heat treatment temperature of the primary on-line heat treatment is controlled at 850 °C, the holding time is 10 - 30 min, the wire traveling speed is 5 - 10 m / min, and the cooling method is argon gas blowing cooling.

10. The method according to claim 9, wherein In step S600, the dehydrogenation + homogenization heat treatment includes: S610, perform vacuum heat treatment, control the heat treatment temperature of the vacuum heat treatment at 800 - 850 °C, the holding time is 2 h - 3 h, and when the temperature drops to 400 °C, fill with 99.999% high-purity argon for cooling; S620, perform secondary on-line heat treatment, the protective gas during the secondary on-line heat treatment is 99.999% high-purity argon, the argon flow rate is 15 - 20 L / min, control the heat treatment temperature of the secondary on-line heat treatment at 850 °C, the holding time is 10 - 30 min, the wire traveling speed is 5 - 10 m / min, and the cooling method is argon gas blowing cooling.

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