High-precision and high-brightness titanium wire processing technology

Abstract

The invention provides a high-precision and high-brightness titanium wire machining process, and belongs to the field of titanium alloy wire machining. The high-precision and high-brightness titanium wire machining technology comprises the steps that S1, materials are prepared, specifically, TC4 type titanium wires are selected; s2, rough wire drawing, wherein the wire is drawn into thin titanium wires through a wire drawing machine; s3, primary annealing: primarily improving the mechanical property of the titanium wire; s4, rough polishing, wherein oxide skin on the surface of the titanium wire is removed; s5, annealing for the second time: further improving the mechanical property of the titanium wire; s6, fine wire drawing, wherein the titanium wire subjected to annealing machining is further stretched; s7, fine polishing is conducted, specifically, the surface of the titanium wire is subjected to fine polishing treatment; and in the step S5, the temperature of secondary annealing is 920 + / -10 DEG C, the machining linear speed is 3 + / -0.1 m / min, and the heat preservation time is 8-10 min. The titanium wire prepared by the method completely meets the requirement of high brightness of a product.

Description

Technical Field

[0001] The present invention relates to the field of titanium alloy wire processing, and particularly relates to a high-precision and high-brightness titanium wire processing technology. Background Art

[0002] The metal braided belt has remarkable characteristics. For example, the metal wires are densely braided without hinges and interfaces. When making a watch band, it fits very well on the hand, showing tough performance and setting off the mature and steady temperament of the wearer. Especially the braided watch band made of titanium alloy has better texture and feels more gentle when worn. Therefore, among the metal braided watch bands designed by customers, the braided watch band made of titanium wire has great advantages, which requires higher appearance and quality requirements in the production and processing of titanium wire.

[0003] Specifically, when producing titanium wire products of 0.65mm * coil grade, it is necessary to ensure that the surface of the titanium wire product is bright with ≤ Ra 0.2, the true roundness reaches 0.01mm, and it is not easy to break. The existing technology cannot meet this production requirement when producing titanium wire. Therefore, it is necessary to improve the titanium wire processing technology. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a high-precision and high-brightness titanium wire processing technology. Through unique processing technology parameter changes, the obtained titanium wire meets the requirements of high precision and high brightness of titanium wire. The present invention achieves the above requirements through process improvement without the need to replace the titanium alloy raw material.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A high-precision and high-brightness titanium wire processing technology, including:

[0007] Material preparation → Rough wire drawing → Annealing → Rough polishing → Annealing → Fine wire drawing → Fine polishing → Quality inspection → Packaging.

[0008] Specifically, it includes the following steps:

[0009] S1. Material preparation: Select high-quality TC4 type titanium wire;

[0010] S2. Rough wire drawing: Use a wire drawing machine to draw the wire into a thinner titanium wire. During the wire drawing process, it is necessary to control the drawing speed and temperature and add a lubricating medium to ensure the accuracy and surface quality of the titanium wire. Specifically, in the rough wire drawing step, the temperature is controlled at 880°C ± 10°C, the cross-sectional reduction ratio is controlled between 45% - 55%, the processing line speed is controlled at 1.5 ± 0.3m / min, and the heat preservation time is 3 - 5min.

[0011] S3. First annealing: Initially improve the mechanical properties of the titanium wire to prevent insufficient toughness and breakage of the material. Specifically, in the first annealing step, the temperature is 920°C ± 10°C, the processing line speed is 3 ± 0.1 m / min, and the heat preservation time is 8 - 10 min.

[0012] S4. Rough polishing: Remove the oxide scale on the surface of the titanium wire by mechanical means. Specifically, in the rough polishing step, the cross-sectional reduction ratio is 1.2% - 1.3%, and the processing line speed is 1 ± 0.3 m / min.

[0013] S5. Second annealing: Further improve the mechanical properties of the titanium wire to prevent insufficient toughness and breakage of the material. Specifically, in the second annealing step, the temperature is 920°C ± 10°C, the processing line speed is 3 ± 0.1 m / min, and the heat preservation time is 8 - 10 min.

[0014] S6. Fine wire drawing: Further stretch the annealed titanium wire to achieve the required precision and brightness. Specifically, in the fine wire drawing step, the temperature is 860°C ± 10°C, the cross-sectional reduction ratio is 2.5% - 2.6%, the processing line speed is 1 ± 0.3 m / min, and the heat preservation time is 2 - 4 min.

[0015] S7. Fine polishing: Treat the surface of the titanium wire by methods such as polishing and grinding to improve its surface finish and brightness. Specifically, in the fine polishing step, the cross-sectional reduction ratio is 1% - 1.1%, and the processing line speed is 1.5 ± 0.1 m / min.

[0016] S8. Quality inspection: Conduct quality inspection on the processed titanium wire, including inspections in aspects such as dimensional accuracy, surface quality, and mechanical properties.

[0017] The process parameter control and functions of each step of the titanium wire processing technology of the present invention are shown in Table 1.

[0018] Table 1

[0019]

[0020] The beneficial effects of the above technical solutions of the present invention are as follows:

[0021] In the above solution, 1. The problem of titanium wire breakage is well solved by using a reasonable annealing temperature and a reasonable heat preservation time; 2. The true roundness is well satisfied by using a suitable cross-sectional reduction ratio for fine wire drawing; 3. The high brightness requirement of the product is fully met by using a reasonable fine polishing line speed. Generally speaking, through unique changes in processing technology parameters, this solution can prepare titanium wire that meets the requirements of high precision and high brightness on the premise of using common titanium alloy raw materials. Specific embodiments

[0022] To make the technical problems, technical solutions, and advantages to be solved by the present invention clearer, the following will be described in detail with reference to specific embodiments.

[0023] Embodiment 1

[0024] This embodiment proposes a high-precision and high-brightness titanium wire processing process, which includes:

[0025] Material preparation → Rough wire drawing → Annealing → Rough polishing → Annealing → Fine wire drawing → Fine polishing → Quality inspection → Packaging.

[0026] Specifically, the high-precision and high-brightness titanium wire processing process includes the following steps:

[0027] S1. Material preparation: Select high-quality TC4 type titanium wire

[0028] S2. Rough wire drawing: Use a wire drawing machine to draw the wire into a thinner titanium wire. During the wire drawing process, it is necessary to control the drawing speed and temperature and add a lubricating medium to ensure the accuracy and surface quality of the titanium wire. During the rough wire drawing process, the temperature is controlled at 880°C, the processing line speed is controlled at 1.5 m / min, the cross-sectional reduction ratio is 50%, and the heat preservation time during the rough wire drawing process is 4 min;

[0029] S3. First annealing: Initially improve the mechanical properties of the titanium wire and prevent the material from having insufficient toughness and breaking. This process is carried out by continuing to heat up to 920°C after rough wire drawing, keeping the processing line speed at 3 m / min, and the heat preservation time is 9 min;

[0030] S4. Rough polishing: Use a mechanical method to remove the oxide scale on the surface of the titanium wire. After the material is cooled, rough polishing is carried out, the processing line speed is 1 m / min, and the cross-sectional reduction ratio of the titanium wire during this process is 1.20%;

[0031] S5. Second annealing: Further improve the mechanical properties of the titanium wire and prevent the material from having insufficient toughness and breaking. After rough polishing, the titanium wire is heated to 920°C, keeping the processing line speed at 3 m / min, and the heat preservation time is 9 min;

[0032] S6. Fine wire drawing: Further draw the titanium wire processed by annealing to achieve the required accuracy and brightness. During the fine wire drawing process, the temperature is controlled at 860°C, the processing line speed is controlled at 1 m / min, the cross-sectional reduction ratio is 2.55%, and the heat preservation time during the rough wire drawing process is 3 min;

[0033] S7. Fine polishing: Use methods such as polishing and grinding to treat the surface of the titanium wire to improve its surface finish and brightness. After the material is cooled, fine polishing is carried out, the processing line speed is 1.5 m / min, and the cross-sectional reduction ratio of the titanium wire during this process is 1.05%;

[0034] S8. Quality inspection: Conduct quality inspection on the processed titanium wire, including inspections in aspects such as dimensional accuracy, surface quality, and mechanical properties.

[0035] For the titanium wire prepared through this embodiment, the yield strength reaches 982 Mpa, the tensile strength reaches 1123 Mpa, the elongation rate reaches 12.28%, the Vickers hardness reaches 292 HV, the surface roughness Ra is 0.18, and the roundness reaches 0.01 mm, meeting the requirements in all aspects.

[0036] Example 2

[0037] This embodiment proposes a high-precision and high-brightness titanium wire processing process, which includes:

[0038] Material preparation → Rough wire drawing → Annealing → Rough polishing → Annealing → Fine wire drawing → Fine polishing → Quality inspection → Packaging.

[0039] Specifically, the high-precision and high-brightness titanium wire processing process includes the following steps:

[0040] S1. Material preparation: Select high-quality TC4 type titanium wire

[0041] S2. Rough wire drawing: Use a wire drawing machine to draw the wire into a thinner titanium wire. During the wire drawing process, it is necessary to control the drawing speed and temperature and add a lubricating medium to ensure the accuracy and surface quality of the titanium wire. During the rough wire drawing process, the temperature is controlled at 870 °C, the processing line speed is controlled at 1.2 m / min, the cross-sectional reduction ratio is 45%, and the heat preservation time during the rough wire drawing process is 3 min;

[0042] S3. First annealing: Initially improve the mechanical properties of the titanium wire to prevent insufficient toughness and fracture of the material. This process is carried out by continuing to heat up to 910 °C after rough wire drawing, maintaining the processing line speed at 2.9 m / min, and the heat preservation time is 8 min;

[0043] S4. Rough polishing: Use a mechanical method to remove the oxide scale on the surface of the titanium wire. After the material cools down, rough polishing is carried out, and the processing line speed is 0.7 m / min. The cross-sectional reduction ratio of the titanium wire during this process is 1.20%;

[0044] S5. Second annealing: Further improve the mechanical properties of the titanium wire to prevent insufficient toughness and fracture of the material. After rough polishing, the titanium wire is heated to 910 °C, maintaining the processing line speed at 2.9 m / min, and the heat preservation time is 8 min;

[0045] S6. Fine wire drawing: Further draw the titanium wire processed by annealing to achieve the required accuracy and brightness. During the fine wire drawing process, the temperature is controlled at 850 °C, the processing line speed is controlled at 0.7 m / min, the cross-sectional reduction ratio is 2.50%, and the heat preservation time during the rough wire drawing process is 2 min;

[0046] S7. Fine polishing: The surface of the titanium wire is treated by methods such as polishing and grinding to improve its surface finish and brightness. Fine polishing is carried out after the material is cooled, the processing line speed is 1.4 m / min, and the cross-sectional reduction ratio of the titanium wire in this process is 1.00%;

[0047] S8. Quality inspection: The processed titanium wire is subjected to quality inspection, including inspections of dimensional accuracy, surface quality, mechanical properties, etc.

[0048] The titanium wire prepared through this embodiment has a yield strength of 975 Mpa, a tensile strength of 1126 Mpa, an elongation rate of 11.92%, a Vickers hardness of 295 HV, a surface roughness Ra of 0.2, and a true roundness of 0.008 mm, meeting the requirements in all aspects.

[0049] Example 3

[0050] This embodiment proposes a high-precision and high-brightness titanium wire processing process, which includes:

[0051] Material preparation → Rough drawing → Annealing → Rough polishing → Annealing → Fine drawing → Fine polishing → Quality inspection → Packaging.

[0052] Specifically, the high-precision and high-brightness titanium wire processing process includes the following steps:

[0053] S1. Material preparation: Select high-quality TC4 type titanium wire

[0054] S2. Rough drawing: Use a drawing machine to draw the wire into a thinner titanium wire. During the drawing process, it is necessary to control the drawing speed and temperature and add a lubricating medium to ensure the accuracy and surface quality of the titanium wire. During rough drawing, the temperature is controlled at 890 °C, the processing line speed is controlled at 1.8 m / min, the cross-sectional reduction ratio is 55%, and the heat preservation time during rough drawing is 5 min;

[0055] S3. First annealing: Initially improve the mechanical properties of the titanium wire and prevent insufficient toughness and fracture of the material. This process is carried out by continuing to heat up to 930 °C after rough drawing, keeping the processing line speed at 3.1 m / min, and the heat preservation time is 10 min;

[0056] S4. Rough polishing: Use a mechanical method to remove the oxide scale on the surface of the titanium wire. Rough polishing is carried out after the material is cooled, the processing line speed is 1.3 m / min, and the cross-sectional reduction ratio of the titanium wire in this process is 1.30%;

[0057] S5. Second annealing: To further improve the mechanical properties of the titanium wire and prevent insufficient toughness and fracture of the material. After rough polishing, the titanium wire is heated to 930 °C, the processing line speed is maintained at 3.1 m / min, and the heat preservation time is 10 min;

[0058] S6. Fine wire drawing: Further draw the annealed titanium wire to achieve the required precision and brightness. During the fine wire drawing process, the temperature is controlled at 870 °C, the processing line speed is controlled at 1.3 m / min, the cross-sectional reduction ratio is 2.60%, and the heat preservation time during the rough wire drawing process is 4 min;

[0059] S7. Fine polishing: Treat the surface of the titanium wire by methods such as polishing and grinding to improve its surface finish and brightness. Fine polishing is carried out after the material is cooled, the processing line speed is 1.6 m / min, and the cross-sectional reduction ratio of the titanium wire during this process is 1.10%;

[0060] S8. Quality inspection: Conduct quality inspection on the processed titanium wire, including inspections of dimensional accuracy, surface quality, mechanical properties, etc.

[0061] For the titanium wire prepared through this embodiment, the yield strength reaches 1067 Mpa, the tensile strength reaches 1125 Mpa, the elongation rate reaches 12.20%, the Vickers hardness reaches 305 HV, the surface roughness Ra is 0.16, and the true roundness reaches 0.007 mm, meeting the requirements in all aspects.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that the temperature of the second annealing is set at 960 °C, which is 40 °C higher than the second annealing temperature in Example 1. When testing the mechanical properties of the titanium wire prepared in Comparative Example 1, it is found that its yield strength, tensile strength, and Vickers hardness meet the requirements, reaching 1100 Mpa, 1120 Mpa, and 286 HV respectively, but the elongation rate is low, only 8.96%. Therefore, it is prone to fracture during the processing and does not meet the production and use requirements.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Example 1 is that the temperature of the second annealing is set at 880 °C, which is 40 °C lower than the second annealing temperature in Example 1. When testing the mechanical properties of the titanium wire prepared in Comparative Example 2, it is found that its yield strength drops to 865 Mpa, the tensile strength changes little and even increases slightly, reaching 1125 Mpa, the Vickers hardness also meets the requirements, remaining at 312 HV, and the elongation rate is still lower than the standard, only 9.04%. Therefore, it is not only prone to fracture during the processing, but also the yield strength does not meet the standard, not meeting the production and use requirements.

[0066] It can be seen from Comparative Example 1 and Comparative Example 2 that the second annealing temperature plays a crucial role in the properties of the titanium wire, especially the elongation of the titanium wire.

[0067] Comparative Example 3

[0068] The difference between this comparative example and Example 1 is only that the heat preservation time of the second annealing is 3 min, and the rest is the same as that of Example 1. When testing the mechanical properties of the titanium wire prepared in Comparative Example 3, it is found that its yield strength is 1160 Mpa, the tensile strength is increased to 1298 Mpa, the Vickers hardness also meets the requirements and remains at 312 HV, but the elongation is still lower than the standard, only 8.65%, so it is easy to break during the processing and does not meet the production and use requirements.

[0069] Comparative Example 4

[0070] The difference between this comparative example and Example 1 is only that the heat preservation time of the second annealing is 15 min, and the rest is the same as that of Example 1. When testing the mechanical properties of the titanium wire prepared in Comparative Example 4, it is found that its yield strength is 860 Mpa, the tensile strength is only 1095 Mpa, the Vickers hardness is only 279 HV, and the elongation exceeds the standard requirement, reaching 14.52%. The hardness does not meet the standard during the processing, so it does not meet the production and use requirements.

[0071] It can be seen from Comparative Example 3 and Comparative Example 4 that the time of the second annealing plays a crucial role in the properties of the titanium wire, especially the elongation and hardness of the titanium wire.

[0072] Comparative Example 5

[0073] The difference between this comparative example and Example 1 is that the cross-sectional reduction ratio of the fine-drawn wire is adjusted to 5%, and the rest is the same as that of Example 1. When testing the mechanical properties of the titanium wire prepared in Comparative Example 5, it is found that its yield strength is 982 Mpa, the tensile strength is 1123 Mpa, the Vickers hardness is 295 HV, and the elongation reaches 12.80%. However, after increasing the cross-sectional reduction ratio, its true roundness becomes extremely poor, only 0.06 mm. Therefore, the titanium wire product of Comparative Example 5 also does not meet the production and use requirements.

[0074] Comparative Example 6

[0075] The difference between this comparative example and Example 1 is that the cross-sectional wire drawing ratio of the fine drawn wire is adjusted to 1%. For Comparative Example 6, it is necessary to perform wire drawing 3 times to obtain titanium wire meeting the specification requirements, which greatly reduces the efficiency. Through the mechanical property test on the titanium wire obtained in Comparative Example 6, it is found that its yield strength is 986 Mpa, tensile strength is 1125 Mpa, Vickers hardness is 298 HV, and elongation reaches 12.76%. However, after reducing the cross-sectional wire drawing ratio, although the true roundness and roughness are not affected, the production rate is greatly reduced. Therefore, too small a cross-sectional wire drawing ratio is not an optimal solution.

[0076] From Comparative Example 5 and Comparative Example 6, it can be seen that when adjusting the cross-sectional wire drawing ratio, on the one hand, if the change amount of the cross-sectional wire drawing ratio during the wire drawing process is too large, it is difficult to ensure the true roundness of the titanium wire, reducing the appearance fineness of the titanium wire. On the other hand, if the change amount of the cross-sectional wire drawing ratio is overly controlled during the wire drawing process, although various properties such as true roundness can meet the requirements, the production efficiency will be greatly reduced, which does not meet the requirements of the enterprise's interests.

[0077] Comparative Example 7

[0078] The difference between this comparative example and Example 1 is that the wire speed of fine polishing is adjusted to 1.0 m / min. The processing and preparation of titanium wire in Comparative Example 7 greatly reduces the efficiency and increases the cost. Through the mechanical property test on the titanium wire obtained in Comparative Example 7, it is found that its yield strength is 985 Mpa, tensile strength is 1125 Mpa, Vickers hardness is 292 HV, and elongation is 11.95%. The true roundness and roughness can meet the requirements. However, after reducing the wire speed of fine polishing, the production rate is greatly reduced. Therefore, reducing the wire speed of fine polishing is not an optimal solution.

[0079] Comparative Example 8

[0080] The difference between this comparative example and Example 1 is that the wire speed of fine polishing is adjusted to 2.0 m / min. The performance of the titanium wire prepared by Comparative Example 8 changes little compared with that of the titanium wire obtained in Comparative Example 7. However, too high a wire speed of fine polishing affects the appearance texture. For example, the roughness exceeds the standard, reaching Ra = 4.2, and the surface is not bright, which does not meet the production and use requirements.

[0081] From Comparative Example 7 and Comparative Example 8, it can be seen that the wire speed of fine polishing is very important for the production and processing of titanium wire. On the one hand, although too low a wire speed has little impact on the performance of the titanium wire product, it greatly reduces the production efficiency, and the production process with a low wire speed will not substantially improve the performance of the titanium wire. On the other hand, too high a wire speed will lead to a significant reduction in processing fineness and poor appearance texture, not meeting the requirements of high-quality products.

[0082] Comparative Example 9

[0083] The difference between this comparative example and Example 1 is that S5: the second annealing is not carried out. When testing the mechanical properties of the titanium wire obtained in Comparative Example 9, it is found that its yield strength is 1102 Mpa, the tensile strength is 1256 Mpa, the Vickers hardness is 310 HV, and the true roundness and roughness meet the requirements. However, the elongation rate is only 6.85%. It is easy to break during processing. Therefore, the titanium wire of Comparative Example 9 does not meet the usage requirements.

[0084] Comparative Example 10

[0085] The difference between this comparative example and Example 1 is that a third annealing step is added after fine wire drawing. The specific conditions for the third annealing are as follows: after fine wire drawing, the titanium wire is heated to 920 °C, the processing line speed is maintained at 3 m / min, and the holding time is 9 min. When testing the mechanical properties of the titanium wire obtained in Comparative Example 10, it is found that its yield strength is 935 Mpa, which is lower than the standard requirement. Other properties such as the tensile strength reach 1058 Mpa, the Vickers hardness is 286 HV, and the true roundness and roughness meet the requirements. Therefore, increasing the number of annealing times by 1 will reduce the yield strength below the standard requirement, making the obtained titanium wire not meet the usage requirements.

[0086] From Comparative Example 9 and Comparative Example 10, it can be seen that although increasing the number of annealing times can improve properties such as yield strength and tensile strength, the elongation rate does not meet the standard. While reducing the number of annealing times can ensure that the elongation rate meets the requirements and can reduce costs, its yield strength does not meet the standard requirements. Therefore, the number of annealing times must be strictly restricted during the processing of titanium wire.

[0087] In the above-mentioned examples and comparative examples, the yield strength was tested by the tensile testing method, the tensile strength was tested by the tensile testing method, the elongation rate was calculated by testing the OMM measurement data, the Vickers hardness was tested by a Vickers hardness tester, the surface roughness was tested by a roughness meter, and the true roundness was tested by a fixed-point detection instrument by rotating the material at multiple angles and reading and recording. The performance test results of the examples and comparative examples are shown in Table 2.

[0088] Table 2

[0089]

[0090] The above is the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle described in the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A high-precision and high-brightness titanium wire processing technology, characterized in that, It includes the following steps: S1. Material preparation: Select TC4 type titanium wire. S2. Rough wire drawing: Use a wire drawing machine to draw the wire into thinner titanium wire. S3. First annealing: Initially improve the mechanical properties of the titanium wire. S4. Rough polishing: Remove the oxide scale on the surface of the titanium wire. S5. Second annealing: Further improve the mechanical properties of the titanium wire. S6. Fine wire drawing: Further draw the titanium wire processed by annealing. S7. Fine polishing: Treat the surface of the titanium wire with fine polishing. Among them, in step S5, the temperature of the second annealing is 920°C ± 10°C, the processing line speed is 3 ± 0.1 m / min, and the heat preservation time is 8 - 10 min.

2. The high-precision and high-brightness titanium wire processing technology according to claim 1, characterized in that, In step S2, the temperature of the rough wire drawing is controlled at 880°C ± 10°C, the processing line speed is controlled at 1.5 ± 0.3 m / min, the cross-sectional reduction ratio is 45% - 55%, and the heat preservation time during the rough wire drawing process is 3 - 5 min.

3. A high-precision and high-brightness titanium wire processing technology according to claim 1, characterized in that, In step S3, the temperature of the first annealing is controlled at 920°C ± 10°C, and the heat preservation time is 8 - 10 min.

4. A high-precision and high-brightness titanium wire processing technology according to claim 1, characterized in that, In step S4, the processing line speed of the rough polishing is 1 ± 0.3 m / min, and the cross-sectional reduction ratio of the titanium wire during this process is 1.2% - 1.3%.

5. A high-precision and high-brightness titanium wire processing technology according to claim 1, characterized in that, In step S5, the temperature of the second annealing is 920°C ± 10°C, and the heat preservation time is 8 - 10 min.

6. A high-precision and high-brightness titanium wire processing technology according to claim 3 or 5, characterized in that, During annealing, the processing line speed is maintained at 3 ± 0.1 m / min.

7. A high-precision and high-brightness titanium wire processing technology according to claim 1, characterized in that, In step S6, the temperature of the fine wire drawing is controlled at 860°C ± 10°C, the cross-sectional reduction ratio is 2.5% - 2.6%, the processing line speed is 1 ± 0.3 m / min, and the heat preservation time is 2 - 4 min.

8. A high-precision and high-brightness titanium wire processing technology according to claim 1, characterized in that, In step S7, the cross-sectional reduction ratio of the fine polishing is 1% - 1.1%, and the processing line speed is 1.5 ± 0.1 m / min.

9. The high-precision and high-brightness titanium wire prepared by the processing technology according to any one of claims 1 - 8, the surface brightness of the titanium wire product is ≤ Ra 0.2, and the true roundness is ≤ 0.01 mm.

10. Application of the high-precision and high-brightness titanium wire prepared by the processing technology according to any one of claims 1 - 8 in high-end watch straps and welding electrodes.

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