Preparation method of alpha and near-alpha type titanium alloy pipe with high strength and high shrinkage strain ratio

Abstract

The invention relates to the technical field of material forming, in particular to a preparation method of a high-strength and high-shrinkage-strain-ratio alpha and near-alpha type titanium alloy pipe. The method comprises the following steps: 1) carrying out Pilger two-roller cogging rolling on a titanium alloy pipe blank to obtain a cogging rolled pipe; (2) after cogging rolling, recrystallization annealing is conducted, and an annealed pipe is obtained; (3) three-roller intermediate rolling is conducted on the titanium alloy pipe subjected to cogging annealing, and an intermediate rolled pipe is obtained; 4) performing vacuum stress relief annealing after intermediate rolling to obtain an intermediate annealed pipe; 5) performing Pilger two-roller finished product rolling on the intermediate annealed pipe to obtain a finished rolled pipe; according to the method, the shrinkage strain ratio of the pipe is remarkably increased, and the technical index requirements for high strength and the high shrinkage strain ratio of the pipe are met. The method comprises the following steps of (1) rolling the pipe into a finished product, (2) carrying out vacuum stress relief annealing on the finished product rolled pipe to obtain a finished product annealed pipe, (3) carrying out finished product straightening on the finished product annealed pipe and (4) carrying out finished product acid pickling on the straightened finished product annealed pipe to obtain the titanium alloy pipe.

Description

Technical Field

[0001] This invention relates to the field of materials forming technology, and in particular to a method for preparing high-strength, high-shrinkage strain ratio α-type and near-α-type titanium alloy tubing. Background Technology

[0002] Key technical indicators for high-performance titanium alloy tubing in aerospace applications include high strength and high contraction strain ratio (CSR). High strength is essential to resist deformation during use, improving material stability and extending service life. High CSR is crucial for meeting the specific high internal pressure environment, thereby enhancing the tubing's ability to resist wall thinning on the inner wall side. Since α / near-α type titanium alloys primarily exhibit an HCP crystal structure, they possess significant anisotropy. This anisotropy is significantly correlated with CSR, thus the tubing processing technology has a crucial impact on CSR. Existing research indicates that a higher cold-rolled Q value (wall reduction rate / diameter reduction rate) results in stronger radial texture and a higher CSR value.

[0003] Current literature on titanium alloy tubing mainly focuses on powder metallurgy, billet preparation, and performance testing and evaluation. In terms of applications, Lockheed Martin pioneered the use of TA18 tubing in the piping system of the C-5A "Galaxy" large military transport aircraft in the 1970s. Subsequently, it was used in the hydraulic and fuel piping systems of military aircraft such as the F-14A and F-15, as well as civilian aircraft from Boeing, General Electric, and Airbus. Besides aerospace applications, near-α type titanium alloy tubing such as TA16 and TA18 is also widely used in space shuttles, satellites, and other fields. It has become a commonly used material in many new military engineering pipe fittings (including helicopters), serving not only in military aircraft systems but also as an indispensable material in civilian aircraft piping systems.

[0004] In recent years, China has conducted research and pilot-scale testing of high-performance titanium alloy tubing for aerospace applications. The core processing technologies involve cold rolling and annealing process design to control the microstructure and properties of the tubing to meet requirements. Typical cold rolling technologies include two-roll and three-roll cold rolling. The main advantage of two-roll cold rolling is its ability to achieve large plastic deformation of the tubing, enabling deformation strengthening to meet high strength performance requirements. However, due to the large deformation per pass and die design limitations, the CSR (Coefficient of Strength) of tubing produced by two-roll cold rolling is relatively low. While three-roll cold rolling can control the CSR to achieve high CSR requirements, insufficient cold rolling deformation makes it difficult to achieve high strength. In summary, high-performance titanium alloy tubing is still in the research and development stage, and stainless steel tubing is currently the primary material used in aircraft hydraulic piping systems. To meet the aerospace industry's demands for lightweight, high-speed, and long-life aircraft, the research and development of high-performance titanium alloys is urgently needed. Therefore, this issue requires immediate attention. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing high-strength, high-shrinkage-strain-ratio α-type and near-α-type titanium alloy tubes. This method significantly improves the shrinkage-strain ratio of the tubes and achieves the technical requirements of high strength and high shrinkage-strain ratio of the tubes. To achieve the aforementioned objective, the technical solution of the present invention is implemented as follows: a method for preparing high-strength, high-shrinkage strain ratio α, near-α type titanium alloy tubing, the method comprising the following steps: S1. Two-roll blanking rolling: The titanium alloy tube blank is cold rolled in one or more passes using a Pilger two-roll cold rolling mill. After each pass of cold rolling, the tube is degreased and pickled to obtain the blanked rolled titanium alloy tube.

[0006] For α / near-α type titanium alloy tubing, the inconsistency of stress and strain in the depth direction during cold deformation, the differences in local grain deformation flow, and the different deformation coordination cause different regions to exhibit different plastic deformation characteristics, resulting in some grains preferentially oriented to form deformation texture.

[0007] When the Q value is less than 1 (mainly due to diameter reduction), diameter reduction deformation dominates during the tube blank rolling process, mainly forming a tangential texture with the base axis orientation in the tangential direction.

[0008] When the Q value is greater than 1 (mainly for wall reduction), wall reduction deformation dominates during rolling, primarily forming a radial texture with the base axis orientation radial. During cold rolling with a large Q value, the grain c-axis approaches the tube normal; during cold rolling with a small Q value, the grain c-axis approaches the tangential direction. To ensure that the grain c-axis continuously approaches the tube normal during deformation and to prevent grains near the tube normal from deviating from the normal direction again during subsequent deformation passes, a large deformation + gradient Q value control approach is adopted for cold rolling in the initial billet rolling stage.

[0009] The deformation during cold rolling is controlled at 50%-70%, and the Q value of each cold rolling pass is >1.0, with the Q value increasing sequentially. This ensures that after each rolling pass, the c-axis of the grains moves closer to the tube normal, thus obtaining a grain orientation conducive to high CSR. After rolling, the tube is degreased at a temperature of 60±10℃ for 10-60 minutes. After degreasing, the tube is pickled, with a wall thickness removal of 0.02-0.2 mm, yielding the rough-rolled titanium alloy tube.

[0010] S2, Opening Annealing: Vacuum annealing is performed on the titanium alloy tubes rolled in each pass of S1 to obtain open-annealed titanium alloy tubes.

[0011] After cold rolling, the tubes need to undergo vacuum annealing to enable them to be further processed. During the crystallization annealing process, the tube texture will change.

[0012] As the annealing temperature increases, the microstructure undergoes initial recrystallization, partial recrystallization, complete recrystallization, and grain growth in sequence. Before complete recrystallization, the radial Cohen coefficient of the {0002} plane of the pipe does not change significantly. During the grain growth stage, the radial Cohen coefficient of the {0002} plane of the pipe gradually decreases, which leads to a decrease in the CSR value of the pipe.

[0013] To ensure that the annealed tubing retains as much of its deformation texture as possible, the selection of the recrystallization annealing temperature is crucial. Different material compositions, deformation processes, and grain orientations all influence the recrystallization temperature. Therefore, before starting the initial annealing process, annealing tests are conducted on samples. After annealing, metallographic analysis is performed on the samples. By determining the degree of recrystallization and grain size, a suitable annealing process is selected. Then, vacuum annealing is performed using the selected process to obtain the initial annealed titanium alloy tubing.

[0014] S3. Three-roll intermediate rolling: The annealed titanium alloy tube obtained in step S2 is cold rolled using a three-roll cold rolling mill. After cold rolling, the tube is degreased to obtain intermediate rolled titanium alloy tube.

[0015] In step S3, the CSR value of the tube is maximized by designing the cold rolling gradient Q value and selecting the annealing process. However, based on the two-roll cold rolling large deformation process design, the tube's Q value is still insufficient. Based on the characteristics of the three-roll cold rolling process, the design approach for this pass differs from that of the initial rolling. By designing a process with small deformation and a large Q value, the radial Cohen coefficient of the tube's {0002} surface is further improved, enhancing the base surface texture strength, thereby increasing the tube's CSR value.

[0016] The cold rolling deformation in this pass is 30%-60%, and the cold rolling Q value is greater than 2.1. After rolling, the tube is degreased at a temperature of 60±10℃ for 10-60 minutes to obtain intermediate rolled titanium alloy tube.

[0017] S4. Intermediate annealing: Vacuum annealing is performed on the intermediate rolled titanium alloy tube obtained in step S3 to obtain intermediate annealed titanium alloy tube.

[0018] Following three-roll cold rolling, the tubes also require vacuum annealing to enable further processing. However, unlike other passes, this cold rolling process involves less deformation, resulting in lower residual stress and dislocation density. Therefore, low-temperature stress-relief annealing not only preserves the tube's strength and improves its plasticity but also retains the deformation texture characteristics of the cold-rolled tube, ensuring a high initial radial texture before final rolling. Intermediate annealing is performed at temperatures ≤600℃ and for 1-3 hours to obtain intermediate-annealed titanium alloy tubes.

[0019] S5. Two-roll finished product rolling: The intermediate annealed titanium alloy tube obtained in step S4 is cold rolled using a Pilger two-roll cold rolling mill. After cold rolling, the tube is degreased to obtain the finished rolled titanium alloy tube.

[0020] Two-roll Pilger cold rolling is used for finished product rolling. The large deformation of this pass is designed to meet the high strength requirements of the tube. At the same time, in order to avoid having a large impact on the radial texture of the tube base surface, the cold rolling Q value is maximized as much as possible based on equipment capacity and tooling design during the cold rolling process.

[0021] The cold rolling deformation is controlled at 60%-80%, and the cold rolling Q value is greater than 1.5. After rolling, the tube is degreased at a temperature of 60±10℃ for 10-60 minutes to obtain the finished rolled titanium alloy tube.

[0022] S6. Finished product annealing: Vacuum annealing is performed on the finished rolled titanium alloy tube obtained in step S5 to obtain the finished annealed titanium alloy tube.

[0023] To ensure that the strength and CSR of the pipes meet the technical requirements, stress-relief annealing is generally selected for finished product annealing. The annealing temperature is 380℃-550℃, and the holding time is 1h-3h to obtain finished annealed titanium alloy pipes.

[0024] S7. Finished product straightening: The finished annealed titanium alloy pipe obtained in step S6 is mechanically straightened to obtain the finished straightened titanium alloy pipe.

[0025] The straightened pipe has a straightness of less than or equal to 0.5 mm / 1000 mm, resulting in a straightened titanium alloy pipe.

[0026] S8. Finished product pickling: The finished straightened titanium alloy pipe obtained in step S7 is subjected to surface pickling to obtain titanium alloy pipe.

[0027] The pickling of the finished product needs to include internal and external surface treatment, and the wall thickness removal is 0.038-0.05mm to obtain titanium alloy pipe.

[0028] Preferably, the rolling speed in step S1 is 50-150 times / min, and the feed rate is 0.5-3.0 mm / time, in order to ensure the surface quality of the cold-rolled tube.

[0029] Preferably, when performing metallographic analysis on the annealed test sample in step S2, the annealing process is preferred to have a completely recrystallized structure with fine, dispersed grains that have not yet grown.

[0030] Preferably, the intermediate rolling speed in step S3 is 50-100 times / min, and the feed rate is 1.0-4.0 mm / time.

[0031] Preferably, the rolling speed of the finished product in step S5 is 100-300 times / min, and the feed rate is 0.5-2.0 mm / time.

[0032] Preferably, the temperature uniformity of the vacuum annealing furnace described in steps S2, S4, and S6 all meet the requirement of ±8℃.

[0033] Preferably, the acid solution in steps S1 and S8 has the following composition and volume fraction: HF: 0.5%-5%, HNO3: 1%-5%, H2O: 80%-95%. When the amount of material removed during the initial pickling and intermediate pipe stages is large, the HF content can be appropriately increased to increase the pickling rate. When the amount of material removed from the finished pipe is small, the HF content can be reduced to ensure both the amount of material removed and the surface quality of the pipe.

[0034] Preferably, the inner and outer surfaces of the finished pipe after pickling in step S8 are free from defects such as pits, scratches, and cracks that are visible to the naked eye, and meet the ultrasonic testing requirements for aerospace titanium alloys.

[0035] The beneficial effects of this invention are reflected in: (1) The method provided by this invention adopts a three-step cold rolling method of two-roll + three-roll + two-roll, making full use of the performance of the two-roll Pilger mill and the three-roll cold rolling tube mill. Each step is designed with reasonable cold rolling deformation, Q value and annealing process, and the mechanical properties and texture distribution of the tube are systematically controlled in each pass from billet to finished product. On the basis of ensuring the high strength level requirements, the shrinkage strain ratio of the tube is significantly improved, realizing the technical indicators of high strength and high shrinkage strain ratio of the tube.

[0036] (2) The method provided by this invention adopts a gradient Q-value cold rolling process. The Q-value is designed to increase sequentially during the cold rolling process, which continuously enhances the radial texture of the base surface of the tube after each cold rolling pass and intensifies the texture concentration. In the tube manufacturing process design, the heritability of the microstructure and the cumulative effect of each pass are fully considered, which provides an important guarantee for the high shrinkage strain ratio of the tube.

[0037] (3) The method provided by this invention is based on the relationship between the process, microstructure and properties of titanium alloy tubes. It systematically and scientifically proposes a method for preparing α / near α type titanium alloy tubes. This method also has certain reference value for zirconium and magnesium alloys with the same crystal structure. Attached Figure Description

[0038] Figure 1 This is a flowchart of the process flow of the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1 like Figure 1 As shown, this invention provides a method for preparing high-strength, high-shrinkage strain ratio α-type and near-α-type titanium alloy tubing. In specific applications, the grade selected is TA2, an α-type titanium alloy. This embodiment includes the following steps: S1. The Φ50×12mm tube blank is subjected to Pilger two-roll cold rolling.

[0041] The first pass rolling reached Φ31.8×7.0mm, with a rolling deformation of 62%, a Q value of 1.15, a rolling speed of 100 times / min, and a feed rate of 1.5mm / pass. The rolled pipe underwent degreasing (oil removal) at 70℃ for 30 minutes. After degreasing, the inner and outer surfaces were pickled using an acid solution with the following ratio: HF:5%, HNO3:40%, H2O:55%. The pickling removal amount on the inner surface was 0.15mm, and the pickling removal amounts on both the inner and outer surfaces were 0.05mm.

[0042] The second rolling pass produces a diameter of Φ19×3.2mm with a rolling deformation of 70%, a Q value of 1.30, a rolling speed of 100 passes / min, and a feed rate of 1.5mm / pass. The rolled pipe is then degreased at 70℃ for 30 minutes. After degreasing, both the inner and outer surfaces are pickled. The pickling removal amount on the inner surface is 0.05mm, and the pickling removal amounts on both the inner and outer surfaces are both 0.05mm.

[0043] S2. Anneal the tube after the first rolling in step S1. Take samples for annealing test before annealing. Observe the metallographic structure and select 575℃ / 3h process to complete the annealing of the first rolled tube.

[0044] The tubes rolled in the second pass of step S1 are annealed. Before annealing, samples are taken for annealing tests. Through metallographic observation, a process of 550℃ / 2h is selected to complete the annealing of the tubes rolled in the second pass.

[0045] S3. The annealed billet obtained in step S2 is subjected to three-roll cold rolling. The cold-rolled dimensions are Φ17×2.0mm, the rolling deformation is 39%, the Q value is 3.3, the rolling speed is 60 times / min, and the feed rate is 2.0mm / batch. The rolled pipe is then degreased at 60℃ for 45min.

[0046] S4. Vacuum annealing is performed on the intermediate pipe obtained in step S3 at a temperature of 500℃ and a holding time of 2h to obtain the intermediate annealed pipe.

[0047] S5. The intermediate annealed tube obtained in step S4 is subjected to Pilger two-roll cold rolling. The cold-rolled size is Φ12×0.9mm, the rolling deformation is 66.7%, the Q value is 1.87, the rolling speed is 150 times / mm, and the feed rate is 1.0mm / batch. The rolled tube is then degreased at a temperature of 65℃ for 60 minutes to obtain the finished rolled tube.

[0048] S6. Vacuum annealing is performed on the finished rolled tube obtained in step S5 at a temperature of 425℃ and a holding time of 2 hours to obtain the finished annealed tube.

[0049] S7. Straighten the finished annealed pipe obtained in step S6. After straightening, the straightness of the pipe is better than 0.5 mm / m, and the finished straightened pipe is obtained.

[0050] S8. The finished straightened pipe obtained in step S7 is pickled on its inner and outer surfaces. The pickling wall thickness removal is 0.04 mm, resulting in a titanium alloy pipe.

[0051] Example 2 like Figure 1 As shown, this invention provides a method for preparing high-strength, high-shrinkage strain ratio α-type and near-α-type titanium alloy tubing. In specific applications, the grade selected is TA18, a near-α-type titanium alloy.

[0052] This embodiment includes the following steps: S1. The Φ65×15mm tube blank is subjected to Pilger two-roll cold rolling.

[0053] The first pass rolling reached Φ44×9mm, with a rolling deformation of 58%, a Q value of 1.24, a rolling speed of 80 times / min, and a feed rate of 2.0mm / pass. The rolled pipe underwent degreasing treatment at 65℃ for 60 minutes. After degreasing, both the inner and outer surfaces were pickled using an acid solution with the following ratio: HF:5%, HNO3:40%, H2O:55%. The pickling removal amount on the inner surface was 0.2mm, and the pickling removal amounts on both the inner and outer surfaces were 0.03mm.

[0054] The second rolling pass produces a diameter of Φ31.75×5.5mm, with a rolling deformation of 54%, a Q value of 1.39, a rolling speed of 120 passes / min, and a feed rate of 1.8mm / pass. The rolled pipe is then degreased at 70℃ for 10 minutes. After degreasing, both the inner and outer surfaces are pickled. The pickling removal amount on the inner surface is 0.08mm, and the pickling removal amount on both the inner and outer surfaces is 0.05mm.

[0055] The third pass rolling process resulted in a diameter of Φ22×3.0mm, a rolling deformation of 60%, a Q value of 1.48, a rolling speed of 150 passes / min, and a feed rate of 1.5mm / pass. The rolled pipe underwent degreasing treatment at 60℃ for 30 minutes. Following degreasing, both the inner and outer surfaces were pickled. The pickling removal amount on the inner surface was 0.06mm, and the pickling removal amounts on both the inner and outer surfaces were 0.03mm.

[0056] S2. Anneal the tube after the first pass of rolling in step S1. Before annealing, take samples to conduct annealing tests. Through metallographic observation, select a process of 650℃ / 3h to complete the annealing of the first pass of rolled tube. Anneal the tube after the second pass of rolling in step S1. Before annealing, take samples to conduct annealing tests. Through metallographic observation, select a process of 625℃ / 3h to complete the annealing of the second pass of rolled tube.

[0057] Annealing is performed on the tube after the third rolling in step S1. Before annealing, samples are taken for annealing tests. Through metallographic observation, the 615℃ / 2h process is selected to complete the annealing of the tube after the third rolling.

[0058] S3. The annealed billet obtained in step S2 is subjected to three-roll cold rolling. The cold-rolled dimensions are Φ19×2.0mm, the rolling deformation is 40%, the Q value is 2.45, the rolling speed is 50 times / min, and the feed rate is 2.5mm / batch. The rolled pipe is then degreased at a temperature of 65℃ for 30 minutes.

[0059] S4. Vacuum annealing is performed on the intermediate pipe obtained in step S3 at a temperature of 575℃ and a holding time of 2h to obtain the intermediate annealed pipe.

[0060] S5. The intermediate annealed tube obtained in step S4 is subjected to Pilger two-roll cold rolling. The cold-rolled size is Φ14×1.0mm, the rolling deformation is 61%, the Q value is 1.9, the rolling speed is 200 times / mm, and the feed rate is 1.2mm / batch. The rolled tube is then degreased at a temperature of 70℃ for 45 minutes to obtain the finished rolled tube.

[0061] S6. Vacuum annealing is performed on the finished rolled tube obtained in step S5 at a temperature of 450°C and a holding time of 2 hours to obtain the finished annealed tube.

[0062] S7. Straighten the finished annealed pipe obtained in step S6. After straightening, the straightness of the pipe is better than 0.5 mm / m, and the finished straightened pipe is obtained.

[0063] S8. The finished straightened pipe obtained in step S7 is pickled on its inner and outer surfaces. The pickling wall thickness removal is 0.05 mm, resulting in a titanium alloy pipe.

[0064] Mechanical properties and shrinkage strain ratio were tested on samples taken from the finished pipes. The mechanical properties (tensile strength at room temperature) of the pipes were >860MPa and the shrinkage strain ratio was >1.8, which met the technical requirements for high strength and high shrinkage strain ratio.

[0065] As can be seen from the above implementation and the method provided by this invention, by adopting a three-step cold rolling method of two rolls + three rolls + two rolls, each step of cold rolling is matched with a suitable vacuum annealing process, and by rationally designing the deformation amount and gradient Q value of each pass, a good combination of tube strength and plasticity is achieved, improving texture concentration and CSR value of the tube. During the two-roll cold rolling process, the Q value is gradually increased to ensure that the radial texture factor of the base surface is continuously strengthened after each rolling pass. During the annealing process, the optimal annealing process is determined experimentally to avoid excessively high annealing temperatures that lead to grain growth, thereby weakening the radial texture factor of the tube. Simultaneously, the deformed grains transform into fine, dispersed equiaxed grains, achieving fine-grain strengthening of the tube. During the three-roll intermediate rolling process, the Q value of the cold rolling is further controlled to achieve concentrated texture distribution. Stress-relief annealing is then applied after cold rolling, which not only preserves the tube's strength level and improves its plasticity to ensure deformation capacity in the next pass, but also retains the deformation texture characteristics. Finally, the two-roll finished product design features large deformation and a large Q value, which strengthens the tube deformation and reduces texture dispersion. Stress-relief annealing is then used after cold rolling to ensure that the tube meets the technical requirements of high strength and high shrinkage strain ratio.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing high-strength, high-shrinkage-strain-ratio α-type, near-α-type titanium alloy tubing, characterized in that, The method comprises the following steps: S1, blooming rolling: adopting a pilger two-roller cold rolling pipe machine to perform single pass or multi-pass cold rolling on the titanium alloy pipe blank, performing oil removal and pickling treatment on the pipe material after each pass of cold rolling to obtain the blooming rolled titanium alloy pipe material; S2, blooming annealing: performing vacuum annealing on the titanium alloy pipe material subjected to each pass of blooming rolling in step S1 to obtain the blooming annealed titanium alloy pipe material; S3, intermediate rolling: adopting a three-roller cold rolling pipe machine to perform cold rolling on the blooming annealed titanium alloy pipe material obtained in step S2, and performing oil removal on the pipe material after cold rolling to obtain the intermediate rolled titanium alloy pipe material; S4, intermediate annealing: performing vacuum annealing on the intermediate rolled titanium alloy pipe material obtained in step S3 to obtain the intermediate annealed titanium alloy pipe material; S5, finished product rolling: adopting a pilger two-roller cold rolling pipe machine to perform cold rolling on the intermediate annealed titanium alloy pipe material obtained in step S4, and performing oil removal on the pipe material after cold rolling to obtain the finished product rolled titanium alloy pipe material; S6, finished product annealing: performing vacuum annealing on the finished product rolled titanium alloy pipe material obtained in step S5 to obtain the finished product annealed titanium alloy pipe material; S7, finished product straightening: performing mechanical straightening on the finished product annealed titanium alloy pipe material obtained in step S6 to obtain the finished product straightened titanium alloy pipe material; S8, finished product pickling: performing surface pickling on the finished product straightened titanium alloy pipe material obtained in step S7 to obtain the titanium alloy pipe material.

2. The method for preparing a high-strength, high-shrinkage-strain-ratio α-type, near-α-type titanium alloy tube according to claim 1, characterized in that, In step S1, the blooming rolling adopts large deformation + gradient Q value control idea for cold rolling, the blooming rolling speed is 50-150 times / min, the feed amount is 0.5-3.0 mm / time, the deformation amount in the cold rolling process is controlled to be 50%-70%, the Q value of each pass of cold rolling is greater than 1.0, and the Q value of each pass of cold rolling increases successively; the oil removal temperature is 60±10℃, and the oil removal time is 10 min-60 min; the wall thickness removal amount of the pickling is 0.02-0.2 mm.

3. The method of claim 1, wherein the high-strength, high-contraction-strain-ratio, near-alpha titanium alloy pipe is characterized by: In step S2, before the blooming annealing starts, a sample is taken to carry out annealing test, and after annealing, metallographic structure analysis is performed on the sample; when the metallographic structure analysis of the annealing test sample is performed, an annealing process is selected in which the sample metallographic structure is completely recrystallized, and the crystal grains are fine and dispersed, and have not grown up, and vacuum annealing is performed by using the selected annealing process.

4. The method of claim 1, wherein the high-strength, high-contraction-strain-ratio, near-alpha titanium alloy pipe is characterized by: In step S4, the intermediate annealing is stress relief annealing, the annealing temperature is less than or equal to 600℃, and the holding time is 1h-3h.

5. The method of claim 1, wherein the high-strength, high-contraction-strain-ratio, near-α titanium alloy pipe is characterized by: In step S5, the finished product rolling speed is 100-300 times / min, and the feed amount is 0.5-2.0 mm / time; the finished product rolling is designed to perform cold rolling with large deformation; the cold rolling deformation amount is 60%-80%, and the cold rolling Q value is greater than 1.5; the oil removal temperature is 60±10℃, and the oil removal time is 10 min-60 min.

6. The method of claim 1, wherein the high-strength, high-contraction-strain-ratio, near-alpha titanium alloy pipe is characterized by: In step S6, the finished product annealing is stress relief annealing, the annealing temperature is 380℃-550℃, and the holding time is 1h-3h.

7. The method of claim 1, wherein the high-strength, high-contraction-strain-ratio, near-alpha titanium alloy pipe is characterized by: In step S7, the straightness of the pipe material after the finished product straightening is less than or equal to 0.5 mm / 1000 mm.

8. The method of claim 1, wherein the high-strength, high-contraction strain ratio a, near-a titanium alloy pipe is characterized by: In step S8, the pickling includes processing the inner and outer surfaces of the finished straightened titanium alloy pipe, with a wall thickness removal amount of 0.038-0.05 mm, and the inner and outer surfaces of the pipe after pickling are free of visible pits, scratches, cracks and other defects, and meet the ultrasonic testing requirements of the aviation titanium alloy.

9. The method of claim 1, wherein the high-strength, high-contraction strain ratio a, near-a titanium alloy pipe is characterized by: In step S3, the intermediate rolling speed is 50-100 times / min, and the feed amount is 1.0-4.0 mm / time; the three-roll cold rolling is performed using a small deformation+large Q value design idea, with a pass cold rolling deformation of 30%-60% and a cold rolling Q value > 2.1; the degreasing temperature is 60±10℃, and the degreasing time is 10-60 min, to obtain the intermediate rolling titanium alloy pipe.

10. The method of producing a high-strength high-shrinkage strain ratio a, near-a titanium alloy pipe according to claim 1 or 3 or 4 or 6 or 8 or 9, characterized in that, In steps S2, S4 and S6, the furnace temperature uniformity of the vacuum annealing furnace meets the requirement of ±8℃; and in steps S1 and S8, the composition and volume fraction of the acid liquid are HF: 0.5%-5%, HNO3: 1%-5%, and H2O: 80%-95%.

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