Preparation method of TA15 titanium alloy cold-rolled pipe

Abstract

The application discloses a preparation method of TA15 titanium alloy cold-rolled pipe, and belongs to the field of titanium alloy pipe processing technology.The method comprises the following steps: firstly, processing a TA15 titanium alloy ingot into a bar blank;secondly, drilling and boring the bar blank to obtain a hollow bar blank;thirdly, after the hollow bar blank is sleeved, the hollow bar blank is heated, extruded, straightened and pickled to obtain an extruded pipe blank;fourthly, the extruded pipe blank is subjected to multi-pass rolling to obtain a rolled pipe;and finally, the rolled pipe is subjected to peeling and boring to obtain the TA15 titanium alloy cold-rolled pipe.Through the selection of equipment, the preparation of the blank, the design of the rolling process and the control of parameters, the TA15 titanium alloy pipe is successfully prepared by the cold-rolling process, the quality of the TA15 titanium alloy cold-rolled pipe is ensured, the yield is improved, the production cost is reduced, the preparation process is simple and easy to implement, the method is suitable for industrial production, can be popularized to the processing of the titanium alloy pipe, and has high practical value.

Description

Technical Field

[0001] This invention belongs to the field of metal material processing technology, and specifically relates to a method for preparing TA15 titanium alloy cold-rolled tubes. Background Technology

[0002] The nominal composition of TA15 titanium alloy is Ti-6.5Al-2Zr-1Mo-1V. It belongs to the near-α type titanium alloy with high Al equivalent. It has the characteristics of high specific strength, good thermal stability, creep resistance, good hot strength and weldability. It is an important structural material in the aerospace field. Its main strengthening mechanism is through solid solution strengthening of the α stabilizing element Al. The addition of neutral element Zr and β stabilizing elements Mo and V can improve the processing performance.

[0003] With the increasingly widespread application of titanium alloys in various fields, the demand for TA15 titanium alloy pipes is also gradually increasing. However, due to the high room temperature strength of TA15 titanium alloy, with a yield strength of approximately 900 MPa, cold working of this alloy pipes presents significant difficulties and limitations. Currently, the main production methods for TA15 titanium alloy pipes are hot extrusion, forging of bars, and skew rolling. Specific production methods and process characteristics are shown in Table 1.

[0004] Table 1 Production methods and technological characteristics of TA15 pipes

[0005]

[0006] Therefore, there is an urgent need for a method to prepare TA15 pipes that has a high yield, low production cost, excellent performance, and can be industrially produced. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a method for preparing TA15 titanium alloy cold-rolled tubes, addressing the shortcomings of the prior art. This method, through the selection of equipment, billet preparation, and the design and parameter control of the rolling process, successfully achieves the cold rolling process for preparing TA15 titanium alloy tubes. This method not only ensures the quality of the TA15 titanium alloy cold-rolled tubes but also improves the yield, reduces production costs, and solves the problem that existing TA15 tubes are difficult to prepare through cold working.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing TA15 titanium alloy cold-rolled tubes, characterized in that the method includes the following steps:

[0009] Step 1: The TA15 titanium alloy ingot, prepared by three vacuum arc furnace melting processes, is processed into billets. The chemical composition of the TA15 titanium alloy ingot meets the requirements of the TA15 grade standard in GB / T3620.1-2016 "Titanium and Titanium Alloy Grades and Chemical Composition". The metallographic structure of the billet is a typical two-phase region structure with no original β grain boundaries, and the billet meets the requirements of A1 grade in GB / T5193-2007 "Methods for Flaw Detection of Titanium and Titanium Alloy Processed Products".

[0010] Step 2: Drill and bore the bar blank from Step 1 to obtain a hollow bar blank;

[0011] Step 3: The hollow bar blank obtained in Step 2 is encased, and then heated, extruded, straightened and pickled to obtain the extruded tube blank;

[0012] Step 4: The extruded tube blank obtained in Step 3 is rolled in multiple passes on an LG type rolling mill to obtain rolled tubes; during the multiple rolling process, the extruded tube blank after each pass is annealed, straightened and surface polished.

[0013] Step 5: After peeling and boring the rolled tube obtained in Step 4 by 0.5mm~0.8mm on one side, TA15 titanium alloy cold-rolled tube is obtained.

[0014] The above-mentioned method for preparing TA15 titanium alloy cold-rolled tubes is characterized in that the α phase content in the metallographic structure of the billet in step one is 30%~50%, and the α phase size is no greater than 50μm. This invention controls the α phase content and size in the billet to adjust the mechanical properties of the subsequently rolled TA15 titanium alloy cold-rolled tubes. This avoids situations where excessive α phase content leads to insufficient strengthening of secondary phases and crack propagation resistance, while insufficient α phase content results in insufficient strengthening effect of the α phase. Simultaneously, it avoids situations where excessively large α phase sizes limit the fragmentation effect of cold deformation during subsequent rolling, thus failing to achieve the desired fine-grain strengthening effect.

[0015] The above-mentioned method for preparing TA15 titanium alloy cold-rolled tubes is characterized in that, in step two, a machining allowance of 0.3mm to 0.6mm is reserved after drilling, and this reserved machining allowance is eliminated by boring to achieve the target inner hole size of the hollow billet. The inner hole roughness of the hollow billet does not exceed 1.6μm, and the wall thickness deviation does not exceed 0.6mm. This invention controls the inner hole roughness of the hollow billet to avoid stress concentration and crack formation during subsequent rolling, while controlling the wall thickness deviation to ensure that the wall thickness deviation can be corrected during subsequent rolling, avoiding excessive wall thickness deviation that cannot be corrected and affects the quality of the cold-rolled tubes.

[0016] The above-mentioned method for preparing TA15 titanium alloy cold-rolled tubing is characterized in that, during the cladding process in step three, the inner hole of the hollow bar billet adopts a double-cladding form of inner steel tube and outer copper tube, and the end face and outer periphery of the hollow bar billet adopt a double-cladding form of inner steel sheet and outer copper sheet; the extrusion adopts a 25MN~63MN horizontal extrusion press, and the heating temperature is (T β -30℃) ~ (T β -80℃), T β The phase transition temperature is expressed in °C. The extrusion speed is 20 mm / s to 50 mm / s, and the extrusion ratio is 6 to 15. The pickling solution used in the pickling process consists of the following components by mass concentration: 30% to 55% HNO3, 3% to 12% HF, and the balance being water.

[0017] The above-mentioned method for preparing TA15 titanium alloy cold-rolled tube is characterized in that, in step four, the total rolling deformation of the multi-pass rolling on the LG type rolling mill is 25%~55%, the feed rate is 3mm / pass~5mm / pass, and the speed is 30 passes / min~60 passes / min.

[0018] The above-mentioned method for preparing TA15 titanium alloy cold-rolled pipe is characterized in that the annealing in step four is carried out using a box-type resistance furnace for heating, and before loading the furnace, an anti-oxidation coating prepared by water, glue and paint in a mass ratio of 1:1:1 is uniformly applied to the inner and outer surfaces of the object to be treated, ensuring that the inner and outer surfaces of the object to be treated are 100% coated without bubbles or paint accumulation. After drying for 60 min to 120 min, the object is loaded into the furnace and annealed at 750℃ to 850℃. Then, it is straightened while hot, and the straightening transfer time is no more than 60 s. The surface is then polished using a polishing machine, and the surface anti-oxidation coating is removed by sequentially using 60#, 80#, 120#, 400#, 600# and 800# flap wheel polishing heads.

[0019] The above-mentioned method for preparing TA15 titanium alloy cold-rolled tube is characterized in that, in step five, the feeding speed for peeling is 200 mm / min to 400 mm / min, the spindle speed is 60 r / min to 120 r / min, the feeding speed for boring is 100 mm / min to 300 mm / min, and the spindle speed is 70 r / min to 140 r / min.

[0020] The above-mentioned method for preparing TA15 titanium alloy cold-rolled tubes is characterized by subjecting the TA15 titanium alloy cold-rolled tubes obtained in step five to dimensional appearance, mechanical properties, hydrostatic testing, and flaw detection. The results show that the wall thickness of the TA15 titanium alloy cold-rolled tubes does not exceed 10% of the nominal wall thickness, and the flaw detection meets the standard flaw requirements: depth 0.2mm × width 0.8mm × length 25mm. The room temperature mechanical properties meet the following requirements: tensile strength Rm = 930MPa~1130MPa, yield strength Rp... 0.2 The TA15 titanium alloy cold-rolled tube prepared by this invention has a strength of ≥855MPa and an elongation after fracture (A) ≥10%. The dimensional appearance, mechanical properties, water pressure, and flaw detection results all meet the requirements for its use.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. This invention involves sequentially drilling and boring, cladding, heating, extrusion, rolling, peeling, and boring of a billet to prepare TA15 titanium alloy cold-rolled tubing. By selecting equipment, preparing billets, designing and controlling the parameters of the rolling process, the cold rolling process for producing TA15 titanium alloy tubing has been successfully realized. This ensures the quality of TA15 titanium alloy cold-rolled tubing, improves the yield, reduces production costs, and is suitable for industrial production.

[0023] 2. This invention employs a double-sleeved design with an inner steel tube and an outer copper tube for the inner hole of the hollow bar billet, and a double-sleeved design with an inner steel sheet and an outer copper sheet for the end face and outer periphery, before extrusion. This avoids the formation of a Ti-Cu eutectic brittle structure at the interface due to direct contact between titanium and copper at high temperatures. At the same time, optimizing the inner hole sleeve material to steel and copper tubes ensures the integrity of the sleeve during the extrusion process and improves the extrusion quality.

[0024] 3. This invention solves the problem of low tube temperature after annealing and difficulty in straightening, and the problem of severe surface oxidation after atmospheric furnace annealing affecting subsequent rolling, by brushing an anti-oxidation coating onto the surface of the extruded tube blank after each rolling pass and then annealing. Furthermore, by adding polishing treatment to remove the surface anti-oxidation coating, adverse effects on the tube surface are avoided.

[0025] 4. Based on the characteristics of TA15 titanium alloy, this invention controls the main parameters such as deformation, feed rate and speed of multi-pass rolling, and limits the rolling equipment to ensure the smooth progress of the rolling process.

[0026] 5. This invention obtains finished pipes by peeling and boring rolled pipes. By limiting the feeding speed and rotation speed of peeling and boring, it ensures that the dimensional accuracy and surface roughness of TA15 titanium alloy cold-rolled pipes meet the requirements of the application standards.

[0027] 6. The preparation process of this invention is simple and easy to implement, and can be extended to the processing of titanium alloy pipes, thus having high practical value.

[0028] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0029] Figure 1 The image shows the metallographic structure of the bar blank prepared in Example 1 of this invention.

[0030] Figure 2 The image shows the metallographic structure of the bar blank prepared in Example 2 of this invention.

[0031] Figure 3 The image shows the metallographic structure of the bar blank prepared in Example 3 of this invention. Detailed Implementation

[0032] In the anti-oxidation coatings used in Examples 1-3 of this invention, the coating material is Ti89 forging coating produced by Shaanxi Xuanming Technology Co., Ltd., and the adhesive is NJ-1 special adhesive produced by Beijing Tianlichuang Glass Technology Development Co., Ltd.

[0033] Example 1

[0034] This embodiment includes the following steps:

[0035] Step 1: The TA15 titanium alloy ingot, prepared by three vacuum arc furnace melting processes, is processed into billets. The chemical composition of the TA15 titanium alloy ingot meets the requirements of the TA15 grade standard in GB / T3620.1-2016 "Titanium and Titanium Alloy Grades and Chemical Compositions". The metallographic structure of the billets is a typical two-phase region structure with no primary β grain boundaries. Figure 1 As shown, the α phase content in the metallographic structure of the billet is 30%, and the α phase size is not greater than 30μm. The billet meets the requirements of grade A1 in GB / T5193-2007 "Methods for Flaw Detection of Titanium and Titanium Alloy Workpieces".

[0036] Step 2: Drill and bore the bar blank from Step 1. After drilling, leave a 0.3mm machining allowance for the inner hole. The reserved machining allowance for the inner hole is eliminated by boring to achieve the target inner hole size of the hollow bar blank, thus obtaining a hollow bar blank. The inner hole roughness of the hollow bar blank is 1.1μm and the wall thickness deviation is 0.5mm.

[0037] Step 3: Perform a sheathing process on the hollow bar billet obtained in Step 2. The inner hole of the hollow bar billet is double-sheathed with an inner steel tube and an outer copper tube. The end face and outer circumference of the hollow bar billet are also double-sheathed with an inner steel sheet and an outer copper sheet. Then heat to T. β -30℃, T βThe phase transformation point temperature is expressed in °C. A 25MN horizontal extrusion press is used for extrusion at a speed of 20 mm / s and an extrusion ratio of 6. The extruded hollow billet is then straightened using residual heat and pickled to remove residual steel and copper scale from the surface, yielding an extruded tube blank. The pickling solution used for pickling consists of the following components by mass concentration: 40% HNO3, 3% HF, and the balance being water.

[0038] Step 4: The extruded tube blank obtained in Step 3 is rolled in multiple passes on an LG type rolling mill. The rolling deformation is 25%~42%, the feed rate is 4mm / pass~5mm / pass, and the speed is 30 / min~40 / min to obtain rolled tube. During the multi-pass rolling process, the extruded tube blank after each pass is annealed, straightened, and surface polished. The annealing is carried out in a box-type resistance furnace, and before loading into the furnace, a water-based coating is evenly applied to the inner and outer surfaces of the object to be treated. An anti-oxidation coating is prepared by mixing adhesive and paint in a 1:1:1 mass ratio, ensuring 100% coverage of the inner and outer surfaces of the object to be treated, without bubbles or paint buildup. After drying for 60 minutes, the object is placed in a furnace and annealed at 750℃. Then, it is straightened while hot, with a straightening transfer time not exceeding 60 seconds. Finally, the surface is polished using a polishing machine, employing 60#, 80#, 120#, 400#, 600#, and 800# blade polishing heads in sequence to remove the surface anti-oxidation coating.

[0039] Step 5: The rolled tube obtained in Step 4 is subjected to peeling and boring processes with a single-sided thickness of 0.5mm. The feed speed for peeling is 400mm / min and the spindle speed is 120r / min. The feed speed for boring is 300mm / min and the spindle speed is 140r / min, to obtain TA15 titanium alloy cold-rolled tube.

[0040] The TA15 titanium alloy cold-rolled tubes prepared in this embodiment were subjected to dimensional appearance, mechanical properties, water pressure and flaw detection inspections. The results showed that the wall thickness deviation of the TA15 titanium alloy cold-rolled tubes did not exceed 0.5 mm (not exceeding ±10% of the wall thickness). The flaw detection met the standard flaws: depth 0.2 mm × width 0.8 mm × length 25 mm. The measured values ​​of the room temperature mechanical properties are shown in Table 2 below.

[0041] Table 2. Room temperature mechanical properties of TA15 titanium alloy cold-rolled tubing prepared in Example 1

[0042]

[0043] Example 2

[0044] This embodiment includes the following steps:

[0045] Step 1: The TA15 titanium alloy ingot, prepared by three vacuum arc furnace melting processes, is processed into billets. The chemical composition of the TA15 titanium alloy ingot meets the requirements of the TA15 grade standard in GB / T3620.1-2016 "Titanium and Titanium Alloy Grades and Chemical Compositions". The metallographic structure of the billets is a typical two-phase region structure with no primary β grain boundaries. Figure 2 As shown, the α phase content in the metallographic structure of the billet is 40%, and the α phase size is not greater than 50μm. The billet meets the requirements of grade A1 in GB / T5193-2007 "Methods for Flaw Detection of Titanium and Titanium Alloy Workpieces".

[0046] Step 2: Drill and bore the bar blank from Step 1. After drilling, leave a 0.6mm machining allowance for the inner hole. The reserved machining allowance for the inner hole is eliminated by boring to achieve the target inner hole size of the hollow bar blank, thus obtaining a hollow bar blank. The inner hole roughness of the hollow bar blank is 1.6μm and the wall thickness deviation is 0.6mm.

[0047] Step 3: Perform a sheathing process on the hollow bar billet obtained in Step 2. The inner hole of the hollow bar billet is double-sheathed with an inner steel tube and an outer copper tube. The end face and outer circumference of the hollow bar billet are also double-sheathed with an inner steel sheet and an outer copper sheet. Then heat to T. β -50℃, T β The phase transformation point temperature is expressed in °C. A 45MN horizontal extrusion press is used for extrusion at a speed of 30 mm / s and an extrusion ratio of 10. The extruded hollow billet is then straightened using residual heat and pickled to remove residual steel and copper scale from the surface, yielding an extruded tube blank. The pickling solution used for pickling consists of the following components by mass concentration: 30% HNO3, 12% HF, and the balance being water.

[0048] Step 4: The extruded tube blank obtained in Step 3 is rolled in multiple passes on an LG type rolling mill. The rolling deformation is 32%~50%, the feed rate is 3mm / pass~4mm / pass, and the speed is 40 / min~60 / min to obtain rolled tube. During the multi-pass rolling process, the extruded tube blank after each pass is annealed, straightened, and surface polished. The annealing is carried out in a box-type resistance furnace, and before loading into the furnace, a water-based coating is evenly applied to the inner and outer surfaces of the object to be treated. An anti-oxidation coating is prepared by mixing adhesive and paint in a 1:1:1 mass ratio, ensuring 100% coverage of the inner and outer surfaces of the object to be treated, without bubbles or paint buildup. After drying for 60 minutes, the object is placed in a furnace and annealed at 800℃. Then, it is straightened while hot, with a straightening transfer time not exceeding 60 seconds. Finally, the surface is polished using a polishing machine, employing 60#, 80#, 120#, 400#, 600#, and 800# blade polishing heads in sequence to remove the surface anti-oxidation coating.

[0049] Step 5: The rolled tube obtained in Step 4 is subjected to peeling and boring processes with a single-sided thickness of 0.8mm. The feed speed for peeling is 200mm / min and the spindle speed is 60r / min. The feed speed for boring is 100mm / min and the spindle speed is 70r / min, to obtain TA15 titanium alloy cold-rolled tube.

[0050] The TA15 titanium alloy cold-rolled tubes prepared in this embodiment were subjected to dimensional appearance, mechanical properties, water pressure and flaw detection inspections. The results showed that the wall thickness deviation of the TA15 titanium alloy cold-rolled tubes did not exceed 0.35 mm (not exceeding ±10% of the wall thickness). The flaw detection met the standard flaws: depth 0.2 mm × width 0.8 mm × length 25 mm. The measured values ​​of the room temperature mechanical properties are shown in Table 3 below.

[0051] Table 3. Room temperature mechanical properties of TA15 titanium alloy cold-rolled tubing prepared in Example 2

[0052]

[0053] Example 3

[0054] This embodiment includes the following steps:

[0055] Step 1: The TA15 titanium alloy ingot, prepared by three vacuum arc furnace melting processes, is processed into billets. The chemical composition of the TA15 titanium alloy ingot meets the requirements of the TA15 grade standard in GB / T3620.1-2016 "Titanium and Titanium Alloy Grades and Chemical Compositions". The metallographic structure of the billets is a typical two-phase region structure with no primary β grain boundaries. Figure 3 As shown, the α phase content in the metallographic structure of the billet is 50%, and the α phase size is not greater than 40μm. The billet meets the requirements of grade A1 in GB / T5193-2007 "Methods for Flaw Detection of Titanium and Titanium Alloy Workpieces".

[0056] Step 2: Drill and bore the bar blank from Step 1. After drilling, leave a 0.4mm machining allowance for the inner hole. The reserved machining allowance for the inner hole is eliminated by boring to achieve the target inner hole size of the hollow bar blank, thus obtaining a hollow bar blank. The inner hole roughness of the hollow bar blank is 1.3μm and the wall thickness deviation is 0.5mm.

[0057] Step 3: Perform a sheathing process on the hollow bar billet obtained in Step 2. The inner hole of the hollow bar billet is double-sheathed with an inner steel tube and an outer copper tube. The end face and outer circumference of the hollow bar billet are also double-sheathed with an inner steel sheet and an outer copper sheet. Then heat to T. β -80℃, T βThe phase transformation point temperature is expressed in °C. A 63MN horizontal extrusion press was used for extrusion at a speed of 50 mm / s and an extrusion ratio of 15. The extruded hollow billet was then straightened using residual heat and pickled to remove residual steel and copper scale from its surface, yielding an extruded tube blank. The pickling solution used consisted of the following components by mass concentration: 55% HNO3, 3% HF, and the remainder being water.

[0058] Step 4: The extruded tube blank obtained in Step 3 is rolled in multiple passes on an LG type rolling mill. The rolling deformation is 36%~55%, the feed rate is 3mm / pass~4mm / pass, and the speed is 40 / min~50 / min to obtain rolled tube. During the multi-pass rolling process, the extruded tube blank after each pass is annealed, straightened, and surface polished. The annealing is carried out in a box-type resistance furnace. Before loading into the furnace, a mixture of water and... An anti-oxidation coating is prepared by mixing adhesive and paint in a 1:1:1 mass ratio, ensuring 100% coverage of the inner and outer surfaces of the object to be treated, without bubbles or paint buildup. After drying for 120 minutes, the object is placed in a furnace and annealed at 850℃. Then, it is straightened while hot, with a straightening transfer time not exceeding 60 seconds. Finally, the surface is polished using a polishing machine, with 60#, 80#, 120#, 400#, 600#, and 800# blade polishing heads used in sequence to remove the surface anti-oxidation coating.

[0059] Step 5: The rolled tube obtained in Step 4 is subjected to peeling and boring processes with a single-sided thickness of 0.6 mm. The feed speed for peeling is 300 mm / min and the spindle speed is 90 r / min. The feed speed for boring is 200 mm / min and the spindle speed is 100 r / min, to obtain TA15 titanium alloy cold-rolled tube.

[0060] The TA15 titanium alloy cold-rolled tubes prepared in this embodiment were subjected to dimensional appearance, mechanical properties, water pressure and flaw detection inspections. The results showed that the wall thickness deviation of the TA15 titanium alloy cold-rolled tubes did not exceed 0.4 mm (not exceeding ±10% of the wall thickness). The flaw detection met the standard flaws: depth 0.2 mm × width 0.8 mm × length 25 mm. The measured values ​​of the room temperature mechanical properties are shown in Table 4 below.

[0061] Table 4. Room temperature mechanical properties of TA15 titanium alloy cold-rolled tubing prepared in Example 3

[0062]

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing TA15 titanium alloy cold-rolled tubing, characterized in that, The method includes the following steps: Step 1: The TA15 titanium alloy ingot, prepared by three vacuum arc furnace melting processes, is processed into billets. The chemical composition of the TA15 titanium alloy ingot meets the TA15 grade standard requirements in GB / T3620.1-2016 "Titanium and Titanium Alloy Grades and Chemical Compositions". The metallographic structure of the billet is a typical two-phase region structure with no original β grain boundaries, and the billet meets the A1 grade requirements in GB / T5193-2007 "Methods for Flaw Detection of Titanium and Titanium Alloy Processed Products". The α phase content in the metallographic structure of the billet is 30%~50%, and the α phase size is not greater than 50μm. Step 2: Drill and bore the bar blank from Step 1 to obtain a hollow bar blank; Step 3: The hollow bar billet obtained in Step 2 is subjected to a sheathing process, followed by heating, extrusion, straightening, and pickling to obtain an extruded tube billet. During the sheathing process, the inner hole of the hollow bar billet is double-sheathed with an inner steel tube and an outer copper tube, and the end face and outer circumference of the hollow bar billet are also double-sheathed with an inner steel sheet and an outer copper sheet. The extrusion process uses a 25MN~63MN horizontal extrusion press, and the heating temperature is (T...). β -30℃) ~ (T β -80℃), T β The phase transition temperature is expressed in °C. The extrusion speed is 20 mm / s to 50 mm / s, and the extrusion ratio is 6 to 15. The pickling solution used in the pickling process consists of the following components by mass concentration: HNO3 30% to 55%, HF 3% to 12%, and the balance being water. Step 4: The extruded tube blank obtained in Step 3 is rolled in multiple passes on an LG-type rolling mill to obtain rolled tubes. During the multiple-pass rolling process, the extruded tube blank after each pass is annealed, straightened, and surface polished. The total rolling deformation on the LG-type rolling mill is 25%~55%, the feed rate is 3mm / pass~5mm / pass, and the speed is 30~60 times / min. The annealing is carried out in a box-type resistance furnace, and before loading into the furnace, a uniform coating is applied to the inner and outer surfaces of the object to be treated. An anti-oxidation coating is prepared by mixing water, glue, and paint in a 1:1:1 mass ratio, ensuring 100% coverage of both the inner and outer surfaces of the object to be treated, without bubbles or paint buildup. After drying for 60-120 minutes, the object is placed in a furnace and annealed at 750-850℃. Then, it is straightened while hot, with a straightening transfer time not exceeding 60 seconds. Finally, the surface is polished using a polishing machine, employing 60#, 80#, 120#, 400#, 600#, and 800# flap wheel heads in sequence to remove the surface anti-oxidation coating. Step 5: After peeling and boring the rolled tube obtained in Step 4 by 0.5mm~0.8mm on one side, TA15 titanium alloy cold-rolled tube is obtained; the feeding speed for peeling is 200mm / min~400mm / min, the spindle speed is 60r / min~120r / min, the feeding speed for boring is 100mm / min~300mm / min, and the spindle speed is 70r / min~140r / min.

2. The method for preparing TA15 titanium alloy cold-rolled tubing according to claim 1, characterized in that, In step two, after drilling, a machining allowance of 0.3mm to 0.6mm is reserved for the inner hole. The reserved machining allowance is eliminated by boring to achieve the target inner hole size of the hollow bar blank. The inner hole roughness of the hollow bar blank does not exceed 1.6μm and the wall thickness deviation does not exceed 0.6mm.

3. The method for preparing TA15 titanium alloy cold-rolled tubing according to claim 1, characterized in that, The TA15 titanium alloy cold-rolled tubes obtained in step five were subjected to dimensional, appearance, mechanical property, hydrostatic, and flaw detection inspections. The results showed that the wall thickness of the TA15 titanium alloy cold-rolled tubes did not exceed 10% of the nominal wall thickness. The flaw detection met the standard flaw requirements: depth 0.2mm × width 0.8mm × length 25mm. The room temperature mechanical properties met the requirements: tensile strength Rm = 930MPa~1130MPa, yield strength Rp 0.2 ≥855MPa, elongation after fracture A≥10%.

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