High-quality TC4 titanium alloy wire and preparation method thereof

Abstract

The invention provides a high-quality TC4 titanium alloy wire and a preparation method thereof, and relates to the technical field of biomedical metal materials, and the preparation method comprises the following steps: preparing materials according to TC4 titanium alloy components, carrying out vacuum consumable smelting, obtaining a titanium ingot blank, carrying out cogging forging, carrying out continuous rolling, heating a TC4 black skin wire to a titanium alloy beta single-phase region temperature, and carrying out high-temperature rounding, then heating the wire material subjected to high-temperature rounding to the titanium alloy alpha + beta two-phase region temperature and carrying out high-temperature rounding again; and finally, peeling and drawing at high temperature. Through a cross-phase region high-temperature rounding process, deformation is carried out in a beta region by utilizing a coupling effect among temperature, tissue and deformation, and strain energy is gathered at a grain boundary; along with the temperature drop after discharging and the temperature drop in the deformation process, the material enters an alpha + beta two-phase region, an alpha phase is preferentially separated out at and near a beta grain boundary containing a large amount of distortion energy and is crushed and spheroidized in the deformation process, and meanwhile, a twisted sheet-shaped alpha phase is formed in the crystal. And the crystal boundary spheroidized alpha phase is uniform and fine, so that the tensile strength of the material is improved.

Description

Technical Field

[0001] The present application relates to the technical field of biomedical metal materials, and more specifically, to a high-quality TC4 titanium alloy wire and a preparation method thereof. Background Art

[0002] With the development of medical metal materials, titanium and titanium-based alloys have been extremely active in the field of implant materials due to their excellent advantages of biocompatibility, corrosion resistance, chemical stability, and non-cytotoxicity. In order to further improve the scope of application of TC4 titanium alloy implant materials, so that they can be implanted alone or used in combination with materials such as polyetheretherketone and carbon fiber, it is very necessary to improve their strength. Poor control of the uniformity, consistency and stability of the TC4 titanium alloy composition will cause unstable mechanical properties of the wire. In the prior art, the process schemes for preparing TC4 titanium alloy wire are:

[0003] The Chinese invention patent with publication number CN117798216A discloses a method for preparing high-performance medical titanium alloy TC4 wire, which comprises the following steps: (1) vacuum consumable melting: using sponge titanium above level 1, metal Al, intermediate alloy AlV, metal Fe, and TiO2, vacuum consumable melting for more than three times to obtain a TC4 titanium alloy ingot that complies with GB / T3620.1-2016; (2) forging and rolling: the forging temperature is 1100℃~12 00℃, rolling temperature is 900℃~950℃; (3) drawing, room temperature, drawing speed ≤5.0m / min; (4) peeling, peeling speed <3.0m / min; (5) roller die drawing, roller die drawing speed ≤5.0m / min, deformation increased to 25%~35%; (6) slider straightening; (7) stress relief heat treatment, heat treatment temperature is 550~650℃, heat preservation, air cooling; (8) centerless grinding, high-performance medical titanium alloy TC4 wire is obtained. The tensile strength of the medical titanium alloy TC4 wire obtained by this preparation scheme is 1007-1248MPa, and the product performance fluctuates greatly.

[0004] The Chinese invention patent with publication number CN115255021A discloses a large unit weight TC4 titanium disc round wire for aerospace fasteners and its preparation method, the preparation method includes: step 1, preparing ingots; step 2, forging and drawing into round billets; step 3, rolling into bars; step 4, heat treatment; step 5, rough and fine drawing; step 6, heat treatment; step 7, sizing and polishing the coiled wire billet after heat treatment in step 6, and then chemically coating the coiled wire billet, and finally preparing a large unit weight TC4 titanium disc round wire for aerospace fasteners. The tensile strength of the TC4 titanium disc round wire obtained by this preparation scheme is between 1001-1022MPa, and the tensile strength after solution and aging treatment is 1209-1283MPa. The tensile strength before solution aging treatment is low, and the strength after treatment fluctuates significantly, and the consistency is poor.

[0005] In order to improve the mechanical properties of TC4 titanium alloy wire implant materials and further expand the application scope of pure titanium implant materials, a preparation method of TC4 titanium alloy wire is needed to improve the tensile strength and provide stable product performance. Summary of the invention

[0006] To solve the above problems, the technical solution adopted in this application is a method for preparing high-quality TC4 titanium alloy wire. According to the composition of TC4 titanium alloy, vacuum consumable smelting is adopted to obtain titanium ingot blank, the titanium ingot blank is forged, and continuous rolling is carried out after forging to obtain TC4 black skin wire. The TC4 black skin wire is heated to the temperature of the titanium alloy β single phase zone for the first rounding, and then the wire after the first rounding is heated to the temperature of the titanium alloy α+β two phase zone for the second rounding; a centerless lathe is used for peeling to obtain white skin wire, and the white skin wire is heated and drawn to obtain TC4 finished coil wire.

[0007] Optionally, the raw materials for batching include sponge titanium of grade one or above, vanadium-aluminum master alloy, aluminum beans, reduced iron powder and titanium dioxide.

[0008] Optionally, vacuum consumable melting is performed three or more times.

[0009] Optionally, the temperature of the billet forging is 1100°C to 1200°C.

[0010] Optionally, the temperature of the continuous rolling is 900° C. to 950° C., the speed of the continuous rolling is 1 m / s to 5 m / s, the deformation amount of each pass in the continuous rolling is 50% to 75%, and the cumulative deformation amount is more than 99.50%.

[0011] Optionally, the TC4 black skin wire is heated to the temperature of the titanium alloy β single phase region for primary rounding, the primary rounding temperature is 980-1030°C, and then the wire after the primary rounding is heated to the titanium alloy α+β two phase region temperature for secondary rounding, the secondary rounding temperature is 900-960°C.

[0012] Optionally, the temperature of the heated drawing is 700-760°C.

[0013] Optionally, the drawing speed of the heated drawing is 1.5 m / min-2.5 m / min, and the diameter reduction of each heated drawing pass is 0.15 mm-0.20 mm.

[0014] Optionally, the heating and drawing process requires the roll to be smooth, and the surface of the white skin wire is coated with a diamond-like structure coating before heating and drawing.

[0015] The present application also provides a high-quality TC4 titanium alloy wire, which is prepared by implementing any of the above-mentioned methods for preparing high-quality TC4 titanium alloy wire.

[0016] The beneficial effects of a high-quality TC4 titanium alloy wire and a preparation method thereof provided in this application are:

[0017] 1. This application uses the coupling effect between temperature, structure and deformation through a cross-phase high-temperature rounding process to deform in the β region and accumulate strain energy at the grain boundaries; with the temperature drop after leaving the furnace and during the deformation process, the material enters the α+β two-phase region, and the α phase is preferentially precipitated at and near the β grain boundary containing a large amount of distortion energy, and is broken and spheroidized during the deformation process, while forming a twisted lamellar α phase in the crystal. The spheroidized α phase at the grain boundary is uniform and fine, which improves the tensile strength of the material and has strong consistency in product performance. At the same time, during the high-temperature drawing process, the surface of the wire is coated with a diamond-like structure coating, which has a low friction coefficient, high bonding strength and heat resistance, so that the surface quality of the wire is significantly improved.

[0018] 2. This application prepares titanium alloy wire by subjecting TC4 wire to high-temperature rounding across phase regions, in which the α phase exists in a uniform, fine, equiaxed shape near the grain boundary. After double annealing heat treatment, the α phase at the grain boundary and within the grain grows slightly. The room temperature tensile strength of the material with this structure is more than 50MPa higher than that of the conventional one. High-temperature drawing is adopted, and the speed of high-temperature drawing and the amount of diameter reduction per pass are strictly controlled to ensure the homogenization of the structure. At the same time, before high-temperature drawing, the surface of the drawn wire is coated with a diamond-like structure coating to reduce friction loss and finally obtain good surface quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art.

[0020] Figure 1 This is the metallographic structure diagram of the finished TC4 titanium alloy wire in Example 1 of the present application;

[0021] Figure 2 This is the metallographic structure diagram of the finished TC4 titanium alloy wire in Example 2 of the present application. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] Example 1

[0024] The TC4 high-quality coiled wire provided in this embodiment includes the following components and the weight percentage of each component: 5.9% Al element, 4.0% V element, 0.12% Fe element, 0.13% O element, 0.017% C element, 0.005% H element, 0.012% N element, and the balance is Ti. It meets the chemical composition requirements of TC4 titanium alloy in GB / T3620.1-2016 standard.

[0025] This embodiment includes the following steps:

[0026] S1: Use first-grade or above sponge titanium, vanadium-aluminum master alloy, aluminum beans, reduced iron powder, and titanium dioxide, and mix according to the composition of TC4 titanium alloy. Use three vacuum consumable smelting processes to obtain TC4 ingots with stable and uniform composition that meet the GB / T3620.1-2016 standard. The sponge titanium grade standard meets the requirements of GB / T2524-2002.

[0027] S2: The Φ600.0mm titanium ingot is forged at 1100°C, and then continuously rolled at 900°C at a rolling speed of 1m / s. The deformation amount of each pass in the continuous rolling is 50%, and the cumulative deformation amount is more than 99.50%. After rolling, the TC4 wire with a size of Φ8.0mm is obtained.

[0028] S3: High-temperature rounding across the phase region: Heat the Φ8.0mm black wire to 980℃ in the titanium alloy β single-phase region, round it to a Φ7.5mm coil, then heat the Φ7.5mm wire to 900℃ in the titanium alloy α+β two-phase region, round it to a Φ7.0mm coil. Finally, use a centerless lathe to peel the wire to obtain a Φ6.7mm white wire.

[0029] S4: High temperature drawing: The heat-treated wire obtained in step S3 is subjected to multiple high temperature drawing. The temperature used in the high temperature drawing process is 700°C to ensure that the wire is heated evenly and does not deform. High temperature drawing requires the reel to be smooth and the surface of the wire to be coated with a diamond-like structural coating. The drawing speed of multiple high temperature drawing is 1.5m / min, and the diameter reduction of each high temperature drawing is 0.15mm. Finally, TC4 coil wire is obtained to obtain a Φ3.0mm finished coil wire. The diamond-like structural coating coated on the surface of the white wire before heating and drawing is a diamond-like carbon (DLC) coating.

[0030] Example 2

[0031] The TC4 high-quality coiled wire provided in this embodiment includes the following components and the weight percentage of each component: 0.42% Fe element, 0.37% O element, 0.0089% C element, 0.0006% H element, 0.0036% N element, and the balance is Ti. It meets the chemical composition requirements of TC4 titanium alloy in GB / T3620.1-2016 standard.

[0032] The difference from Example 1 is that in this embodiment, a Φ600.0mm titanium ingot blank is forged at 1125°C, and after forging, it is continuously rolled at 910°C, with a rolling speed of 2m / s. The deformation amount in each pass of continuous rolling is 55%, and the cumulative deformation amount is more than 99.50%. The black skin wire is heated to 990°C, the temperature of the titanium alloy β single phase zone, and the first high temperature rounding is performed, and then the black skin wire is heated to 915°C, the temperature of the titanium alloy α+β two phase zone, and the second high temperature rounding is performed. The temperature used in the high temperature drawing process is 715°C, the drawing speed of multiple high temperature drawing is 2m / min, and the diameter reduction of each high temperature drawing is 0.2mm.

[0033] Example 3

[0034] The difference from Example 1 is that in this embodiment, a Φ600.0mm titanium ingot blank is forged at 1150°C, and after forging, it is continuously rolled at 920°C, with a rolling speed of 3m / s. The deformation amount of each pass in the continuous rolling is 60%, and the cumulative deformation amount is more than 99.50%. The black skin wire is heated to 1000°C, the temperature of the titanium alloy β single phase zone, and the first high temperature rounding is performed, and then the black skin wire is heated to 930°C, the temperature of the titanium alloy α+β two phase zone, and the second high temperature rounding is performed. The temperature used in the high temperature drawing process is 730°C, the drawing speed of multiple high temperature drawing is 2.5m / min, and the diameter reduction of each high temperature drawing is 0.15mm.

[0035] Example 4

[0036] The difference from Example 1 is that in this embodiment, a Φ600.0mm titanium ingot blank is forged at 1175°C, and after forging, it is continuously rolled at 930°C, with a rolling speed of 4m / s. The deformation amount of each pass in the continuous rolling is 65%, and the cumulative deformation amount is more than 99.50%. The black skin wire is heated to 1010°C, a temperature of the titanium alloy β single phase zone, and the first high temperature rounding is performed, and then the black skin wire is heated to 945°C, a temperature of the titanium alloy α+β two phase zone, and the second high temperature rounding is performed. The temperature used in the high temperature drawing process is 745°C, the drawing speed of multiple high temperature drawing is 1.5m / min, and the diameter reduction of each high temperature drawing is 0.15mm.

[0037] Example 5

[0038] The difference from Example 1 is that in this embodiment, a Φ600.0mm titanium ingot blank is forged at 1200°C, and after forging, it is continuously rolled at 940°C, with a rolling speed of 5m / s. The deformation amount of each pass in the continuous rolling is 70%, and the cumulative deformation amount is more than 99.50%. The black skin wire is heated to 1020°C, a temperature of the titanium alloy β single phase zone, and the first high temperature rounding is performed, and then the black skin wire is heated to 960°C, a temperature of the titanium alloy α+β two phase zone, and the second high temperature rounding is performed. The temperature used in the high temperature drawing process is 760°C, the drawing speed of multiple high temperature drawing is 1.5m / min, and the diameter reduction of each high temperature drawing is 0.15mm.

[0039] Example 6

[0040] The difference from Example 1 is that in this embodiment, a Φ600.0mm titanium ingot blank is forged at 1100°C, and after forging, it is continuously rolled at 950°C, with a rolling speed of 1m / s. The deformation amount in each pass of continuous rolling is 75%, and the cumulative deformation amount is more than 99.50%. The black skin wire is heated to 1030°C, the temperature of the titanium alloy β single phase zone, and the first high temperature rounding is performed, and then the black skin wire is heated to 900°C, the temperature of the titanium alloy α+β two phase zone, and the second high temperature rounding is performed. The temperature used in the high temperature drawing process is 700°C, the drawing speed of multiple high temperature drawing is 1.5m / min, and the diameter reduction of each high temperature drawing is 0.15mm.

[0041] Table 1 Mechanical properties test statistics of Example 1 to Example 6

[0042] Sample No. <![CDATA[Tensile strength R m (MPa)]]> <![CDATA[Yield strength R p0.2 (MPa)]]> Elongation A(%) 1 1238 1136 12.5 2 1223 1125 12.5 3 1237 1111 13.0 4 1227 1129 13.0 5 1210 1130 14.0 6 1215 1120 13.0

[0043] As shown in Table 1, the results of the embodiment show that the present invention uses a centerless lathe to peel the wire after high-temperature rounding in the cross-phase region, and uses high-temperature wire drawing to peel the wire after high-temperature drawing, which can effectively remove surface defects, ensure the surface grain size and roughness of the wire, and improve the tensile strength of the material. The mechanical properties fully meet the requirements of the GB / T13810-2017 standard, and the product performance consistency is strong. At the same time, the lubrication measures during high-temperature drawing can ensure the surface quality of the wire, and obtain high-quality TC4 titanium alloy wire with high tensile strength, high yield strength and excellent surface quality.

[0044] from Figure 1 and Figure 2 It can be seen that the α phase is broken and spheroidized in the subsequent deformation process, and a distorted lamellar α phase structure is formed in the crystal. This uniform and fine spheroidized α phase at the grain boundary not only improves the tensile strength of the material, but also coordinates the plastic deformation under the action of external force to a certain extent, avoiding the shortcomings brought by the Widmanstatten organization structure.

[0045] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for preparing high-quality TC4 titanium alloy wire, characterized in that: According to the TC4 titanium alloy composition, vacuum consumable smelting is adopted to obtain a titanium ingot blank, the titanium ingot blank is subjected to open forging, and after forging, continuous rolling is carried out to obtain TC4 black skin wire after rolling, the TC4 black skin wire is heated to the temperature of the titanium alloy β single phase region for primary rounding, and then the wire after the primary rounding is heated to the temperature of the titanium alloy α+β two phase region for secondary rounding; a centerless lathe is used for peeling to obtain a white skin wire, and the white skin wire is heated and drawn to obtain a TC4 finished coil wire.

2. The method for preparing high-quality TC4 titanium alloy wire according to claim 1, characterized in that: The raw materials for batching include first-grade and above titanium sponge, vanadium-aluminum master alloy, aluminum beans, reduced iron powder and titanium dioxide.

3. The method for preparing high-quality TC4 titanium alloy wire according to claim 2, characterized in that: The vacuum consumable melting is performed more than three times.

4. The method for preparing high-quality TC4 titanium alloy wire according to claim 2, characterized in that: The temperature of the blank forging is 1100°C to 1200°C.

5. The method for preparing high-quality TC4 titanium alloy wire according to claim 2, characterized in that: The temperature of the continuous rolling is 900° C. to 950° C., the speed of the continuous rolling is 1 m / s to 5 m / s, the deformation amount of each pass in the continuous rolling is 50% to 75%, and the cumulative deformation amount is more than 99.50%.

6. The method for preparing high-quality TC4 titanium alloy wire according to claim 2, characterized in that: The TC4 black skin wire is heated to the temperature of the titanium alloy β single phase region for primary rounding, the primary rounding temperature is 980-1030°C, and then the wire after the primary rounding is heated to the temperature of the titanium alloy α+β two phase region for secondary rounding, the secondary rounding temperature is 900-960°C.

7. The method for preparing high-quality TC4 titanium alloy wire according to claim 1, characterized in that: The temperature of the heating drawing is 700-760°C.

8. The method for preparing high-quality TC4 titanium alloy wire according to claim 1, characterized in that: The drawing speed of the heating drawing is 1.5m / min-2.5m / min, and the diameter reduction of each heating drawing is 0.15mm-0.20mm.

9. The method for preparing high-quality TC4 titanium alloy wire according to claim 2, characterized in that: The heating and drawing process requires that the reel is smooth, and the surface of the white skin wire is coated with a diamond-like structure coating before heating and drawing.

10. A high-quality TC4 titanium alloy wire, characterized by: The high-quality TC4 titanium alloy wire is prepared by the drawing method according to any one of claims 1 to 9.

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