Production method for improving yield of titanium alloy seamless tube
By adding tantalum to the production of seamless titanium alloy tubes and adopting specific processing techniques, the problems of complex processing and low yield have been solved, resulting in high yield and improved surface quality.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- CHENGDU ADVANCED METAL MATERIALS IND TECH RES INST CO LTD
- Filing Date
- 2025-06-17
- Publication Date
- 2026-07-09
Abstract
Description
A production method for improving the yield of seamless titanium alloy tubes
[0001] This application claims priority to Chinese Patent Application No. 202510017711.8, filed on January 6, 2025, entitled "A Production Method for Improving the Yield of Seamless Titanium Alloy Tubes", the entire contents of which are incorporated herein by reference. Technical Field
[0002] This invention relates to the fields of alloy and smelting technology, and more specifically, to a production method for improving the yield of seamless titanium alloy tubes. Background Technology
[0003] Seamless titanium alloy tubes possess excellent room-temperature mechanical properties and corrosion resistance, making them widely used in aerospace, nuclear power, and oilfield fields. Common processing techniques for seamless titanium alloy tubes include forging, extrusion, machining, cold rolling, and annealing; alternatively, a combination of forging, machining, cold rolling, and annealing may be employed.
[0004] Due to the narrow temperature range of high-temperature deformation, high resistance to low-temperature deformation, and severe work hardening of titanium alloy materials, the above processing methods are complex and have a low yield, especially for seamless titanium alloy tubes with a diameter of less than 20mm, where the yield is less than 30%. Summary of the Invention
[0005] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a production method for improving the yield of seamless titanium alloy tubes. This method can improve the yield of tubes and is especially suitable for seamless titanium alloy tubes with a diameter of less than 20mm. It has broad application prospects and can be applied to important or key components such as hydraulic lines and fuel lines in aircraft.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows:
[0007] A method for improving the yield of seamless titanium alloy tubes includes the following steps:
[0008] (1) Mix the raw materials and press them into multiple electrode blocks. Weld the multiple electrode blocks together to obtain a consumable electrode.
[0009] (2) Add tantalum, an alloying element with a mass percentage of 0.001% to 0.05%, to the consumable electrode and melt it twice using a vacuum consumable arc furnace to obtain a titanium alloy ingot.
[0010] (3) The titanium alloy ingot is held at 950℃~1150℃ for 4.5h~7h and then subjected to multi-pass hot continuous rolling to obtain titanium alloy bar.
[0011] (4) The surface of the titanium alloy bar is machined and kept at 900℃~1050℃ for 1.5h~3.5h, and then skew-rolled and pierced to form a rough tube;
[0012] (5) The capillary tube is pickled and then subjected to one cold rolling to obtain a tube blank;
[0013] (6) The tube blank is internally bored and externally machined, and then subjected to multiple cold rolling passes to obtain a titanium alloy seamless tube semi-finished product;
[0014] (7) The titanium alloy seamless tube semi-finished product is subjected to vacuum annealing, pickling and polishing in sequence to obtain the titanium alloy seamless tube.
[0015] Optionally, in step (3), the deformation amount of the first and last passes is ≤20%, and the maximum deformation amount is ≤60%.
[0016] Optionally, in step (4), the deformation of the capillary tube is 15% to 30%, and the ratio of the capillary tube diameter to the rod diameter is (1 to 1.2):1.
[0017] Optionally, in step (5), the cold rolling deformation is ≤10%.
[0018] Optionally, in step (6), the deformation amount of the last pass of the multi-pass cold rolling is ≤20%, and the deformation amount of the remaining passes is ≥30%; the intermediate annealing temperature of each pass is 600℃~800℃, and the annealing temperature of the next pass is not greater than the annealing temperature of the previous pass, and the holding time is 1h~2.5h.
[0019] Optionally, the outer diameter of the titanium alloy seamless tube semi-finished product is ≤20mm.
[0020] Optionally, in step (7), the annealing temperature is 350℃~600℃ and the holding time is 1h~2h.
[0021] Optionally, in step (7), the polishing is performed by abrasive flow polishing, and the abrasive is SiC with a particle size of 0.005mm to 0.5mm. After polishing, the roughness of the inner and outer surfaces of the tube is ≤150nm.
[0022] Optionally, in step (2), the diameter of the titanium alloy ingot is ≤700mm.
[0023] The present invention also discloses a production method for improving the yield of seamless titanium alloy tubes as described above, which produces seamless titanium alloy tubes.
[0024] Implementing the embodiments of the present invention will have the following beneficial effects:
[0025] This invention provides a production method for improving the yield of seamless titanium alloy tubes. By adding the alloying element tantalum, the hot deformation capability of the ingot is enhanced, allowing it to be directly hot-rolled into a billet, replacing forging and improving the yield of the billet. As hot rolling proceeds, the alloy structure is improved, the deformation capability is enhanced, and the deformation amount gradually increases. Subsequent hot rolling passes require a reduction in deformation amount due to the temperature rise. Skew rolling piercing is used instead of drilling before machining or extrusion, improving the yield of the tube blank. The first pass of small-deformation cold rolling of the tube blank improves the ovality of the tube blank, increasing the yield of subsequent internal boring and external turning. Subsequent multi-pass cold rolling results in minimal material loss, and the yield of the seamless tube can reach over 40%. The final polishing is used to eliminate burrs that may exist on the inner and outer surfaces of small-diameter seamless tubes and improve roughness, increasing the pass rate of the tube. Detailed Implementation
[0026] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.
[0027] A method for improving the yield of seamless titanium alloy tubes includes the following steps:
[0028] (1) Mix the raw materials and press them into multiple electrode blocks. Weld the multiple electrode blocks together to obtain a consumable electrode.
[0029] (2) Add 0.001% to 0.05% by mass of tantalum alloying element to the consumable electrode and melt it twice in a vacuum consumable arc furnace to obtain a titanium alloy ingot.
[0030] In one specific embodiment, in step (2), the diameter of the titanium alloy ingot is ≤700mm.
[0031] Specifically, this invention improves the cold and hot workability of the alloy by adding the alloying element tantalum.
[0032] (3) The titanium alloy ingot is kept at 950℃~1150℃ for 4.5h~7h and then subjected to multiple hot rolling passes to obtain titanium alloy bars.
[0033] In one specific embodiment, in step (3), the deformation amount of the first pass and the last pass is ≤20%, and the maximum deformation amount is ≤60%.
[0034] Specifically, as hot rolling proceeds, the alloy structure is improved, the deformation capacity is enhanced, and the deformation amount gradually increases.
[0035] (4) The surface of the titanium alloy bar is machined and kept at 900℃~1050℃ for 1.5h~3.5h, and then skew rolling and piercing is performed to form a rough tube.
[0036] In one specific embodiment, in step (4), the deformation of the capillary tube is 15% to 30%, and the ratio of the capillary tube diameter to the rod diameter is (1 to 1.2):1.
[0037] Specifically, this invention uses skew rolling piercing instead of drilling before machining or extrusion, which improves the yield of the tube.
[0038] (5) The capillary tube is pickled and then subjected to one cold rolling to obtain a tube blank.
[0039] In one specific embodiment, in step (5), the cold rolling deformation is ≤10%.
[0040] (6) The tube blank is internally bored and externally machined, and then subjected to multiple cold rolling passes to obtain a titanium alloy seamless tube semi-finished product.
[0041] In a specific embodiment, in step (6), the deformation amount of the last pass of the multi-pass cold rolling is ≤20%, and the deformation amount of the remaining passes is ≥30%; the intermediate annealing temperature of each pass is 600℃~800℃, and the annealing temperature of the next pass is not greater than the annealing temperature of the previous pass, and the holding time is 1h~2.5h.
[0042] In one specific embodiment, the outer diameter of the titanium alloy seamless tube semi-finished product is ≤20mm.
[0043] Specifically, this invention improves the ovality of the tube by setting a small deformation cold rolling in the first pass, thereby increasing the yield of subsequent inner boring and outer turning. Subsequent multiple cold rolling passes result in minimal material loss, and the yield of seamless tubes can reach over 40%.
[0044] (7) The titanium alloy seamless tube semi-finished product is subjected to vacuum annealing, pickling and polishing in sequence to obtain the titanium alloy seamless tube.
[0045] In one specific embodiment, in step (7), the annealing temperature is 350℃~600℃ and the holding time is 1h~2h.
[0046] In one specific embodiment, in step (7), the polishing is carried out by abrasive flow polishing, and the abrasive is SiC with a particle size of 0.005mm to 0.5mm. After polishing, the roughness of the inner and outer surfaces of the tube is ≤150nm.
[0047] Specifically, the polishing process of this invention is used to eliminate burrs that may exist on the inner and outer surfaces of small-diameter seamless pipes and improve roughness, thereby increasing the yield of qualified pipes.
[0048] The present invention also discloses a production method for improving the yield of seamless titanium alloy tubes as described in any embodiment of the present invention.
[0049] Example 1
[0050] The production process for TA18 titanium alloy seamless tubes with a specification of Φ18×3.3mm is as follows: Raw materials are mixed and pressed into multiple electrode blocks; these blocks are then welded to obtain a Φ600mm consumable electrode; tantalum (0.01% by mass) is added to the consumable electrode, and the mixture is melted twice in a vacuum consumable arc furnace to obtain a titanium alloy ingot; the ingot is then held at 1150℃ for 6 hours and subjected to multi-pass hot rolling, with a deformation of 16% in the first pass and 39% in the second pass. The third pass deformation was 51%, the fourth pass 56%, the fifth pass 23%, and the sixth pass 19%, yielding a Φ158mm bar. The titanium alloy bar was then machined to obtain a Φ148mm bar with a yield of 87.7%. This bar was held at 1000℃ for 1.5 hours and then skew-rolled and pierced to form a Φ156*31mm tube with a deformation of 29%. The tube was then pickled and cold-rolled in one pass to obtain a Φ154*28mm tube blank with a deformation of 9%. The tube blank was then internally bored and externally machined to a Φ1... 50*24mm, yield 85.7%, vacuum annealed at 800℃ for 2 hours; cold rolled to Φ128*18mm, deformation 34.5%; vacuum annealed at 780℃ for 2 hours; cold rolled to Φ100*15mm, deformation 35.6%; vacuum annealed at 750℃ for 1.5 hours; cold rolled to Φ75*12mm, deformation 40.7%; vacuum annealed at 750℃ for 1.5 hours; cold rolled to Φ50*10mm, deformation 47.1%; vacuum annealed at 750℃ for 1.5 hours; cold rolled to Φ36*8mm, deformation 4... 4%; vacuum annealing at 750℃ for 1.5h; cold rolling to Φ28*6mm, deformation amount 41.1%; vacuum annealing at 750℃ for 1.5h; cold rolling to Φ24*4mm, deformation amount 39.4%; vacuum annealing at 750℃ for 1.5h; cold rolling to Φ20*3.6mm, deformation amount 26.2%; vacuum annealing at 750℃ for 1h; cold rolling to Φ18*3.3mm, deformation amount 17.8%; straightening, pickling, vacuum annealing at 600℃ for 2h, abrasive flow polishing, and multiple cold rolling passes to obtain titanium alloy seamless tube semi-finished product.
[0051] In this embodiment, after internal boring and external turning of the tube, the yield of each cold rolling pass is 95%. The yield of the TA18 titanium alloy seamless tube from the ingot is 87.7% * 85.7% * 95% * 95% * 95% * 95% * 95% * 95% * 95% * 95% = 47%. After abrasive flow polishing, the inner surface roughness is 0.3 μm, the outer surface roughness is 0.18 μm, and the qualified product rate is 93%.
[0052] Example 2
[0053] The production process for TA16 titanium alloy seamless tubes with a specification of Φ20×1.8mm is as follows: Raw materials are mixed and pressed into multiple electrode blocks; these blocks are then welded to obtain a Φ500mm consumable electrode; 0.02% tantalum alloy is added to the consumable electrode, and the mixture is melted twice in a vacuum consumable arc furnace to obtain a titanium alloy ingot; the ingot is then held at 1100℃ for 5 hours and subjected to multi-pass hot rolling, with a deformation rate of 19% in the first pass and 19% in the second pass. The deformation was 40% in the first pass, 49% in the third pass, 42% in the fourth pass, 38% in the fifth pass, 36% in the sixth pass, 22% in the seventh pass, and 17% in the eighth pass, resulting in a Φ105mm bar. The titanium alloy bar was then machined to obtain a Φ105mm bar with a yield of 83.4%. After holding at 1020℃ for 1.5 hours, it was skew-rolled and pierced to form a Φ115*21mm tube. The tube was then pickled and subjected to a single cold rolling pass to obtain a Φ110*2mm tube. 0mm, deformation amount 8.8%, to obtain tube blank; the tube blank is internally and externally bored to 106*16mm, yield 80%, vacuum annealed at 800℃ for 2h; cold rolled to Φ128*18mm, deformation amount 34.5%; vacuum annealed at 780℃ for 2h; vacuum annealed at 780℃ for 2h; cold rolled to Φ78*11mm, deformation amount 48.8%; vacuum annealed at 760℃ for 2h; cold rolled to Φ60*18mm, deformation amount 43.6%; vacuum annealed at 750℃ for 1.5h; cold rolled to Φ44*6mm, Deformation amount 45%; vacuum annealing at 750℃ for 1.5h; cold rolling to Φ34*4mm, deformation amount 47%; vacuum annealing at 750℃ for 1.5h; cold rolling to Φ24*3mm, deformation amount 47.5%; vacuum annealing at 750℃ for 1.5h; cold rolling to Φ22*2mm, deformation amount 46.5%; vacuum annealing at 750℃ for 1.5h; cold rolling to Φ20*1.8mm, deformation amount 18.1%; straightening, pickling; vacuum annealing at 650℃ for 2h; abrasive flow polishing to obtain a semi-finished titanium alloy seamless tube.
[0054] In this embodiment, after internal boring and external turning of the tube, the yield of each cold rolling pass is 95%. The yield of the TA16 titanium alloy seamless tube from the ingot is 83.4% * 80% * 95% * 95% * 95% * 95% * 95% * 95% * 95% = 46.6%. After abrasive flow polishing, the inner surface roughness is 0.25 μm, the outer surface roughness is 0.15 μm, and the qualified product rate is 95%.
[0055] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.
Claims
1. A production method for improving the yield of seamless titanium alloy tubes, characterized in that, Includes the following steps: (1) Mix the raw materials and press them into multiple electrode blocks. Weld the multiple electrode blocks together to obtain a consumable electrode. (2) Add tantalum, an alloying element with a mass percentage of 0.001% to 0.05%, to the consumable electrode and melt it twice using a vacuum consumable arc furnace to obtain a titanium alloy ingot. (3) The titanium alloy ingot is held at 950℃~1150℃ for 4.5h~7h and then subjected to multi-pass hot continuous rolling to obtain titanium alloy bar. (4) The surface of the titanium alloy bar is machined and kept at 900℃~1050℃ for 1.5h~3.5h, and then skew-rolled and pierced to form a rough tube; (5) The capillary tube is pickled and then subjected to one cold rolling to obtain a tube blank; (6) The tube blank is internally bored and externally machined, and then subjected to multiple cold rolling passes to obtain a titanium alloy seamless tube semi-finished product; (7) The titanium alloy seamless tube semi-finished product is subjected to vacuum annealing, pickling and polishing in sequence to obtain the titanium alloy seamless tube.
2. The production method for improving the yield of seamless titanium alloy tubes according to claim 1, characterized in that, In step (3), the deformation amount of the first and last passes is ≤20%, and the maximum deformation amount is ≤60%.
3. The production method for improving the yield of seamless titanium alloy tubes according to claim 1, characterized in that, In step (4), the deformation of the capillary tube is 15% to 30%, and the ratio of the capillary tube diameter to the rod diameter is (1 to 1.2):
1.
4. The production method for improving the yield of seamless titanium alloy tubes according to claim 1, characterized in that, In step (5), the cold rolling deformation is ≤10%.
5. The production method for improving the yield of seamless titanium alloy tubes according to claim 1, characterized in that, In step (6), the deformation amount of the last pass of the multi-pass cold rolling is ≤20%, and the deformation amount of the remaining passes is ≥30%; the intermediate annealing temperature of each pass is 600℃~800℃, and the annealing temperature of the next pass is not greater than the annealing temperature of the previous pass, and the holding time is 1h~2.5h.
6. The production method for improving the yield of seamless titanium alloy tubes according to claim 1, characterized in that, The outer diameter of the semi-finished titanium alloy seamless tube is ≤20mm.
7. The production method for improving the yield of seamless titanium alloy tubes according to claim 1, characterized in that, In step (7), the annealing temperature is 350℃~600℃ and the holding time is 1h~2h.
8. The production method for improving the yield of seamless titanium alloy tubes according to claim 1, characterized in that, In step (7), the polishing is performed by abrasive flow polishing, and the abrasive is SiC with a particle size of 0.005mm to 0.5mm. After polishing, the surface roughness of the inner and outer surfaces of the tube is ≤150nm.
9. The production method for improving the yield of seamless titanium alloy tubes according to claim 1, characterized in that, In step (2), the diameter of the titanium alloy ingot is ≤700mm.
10. A titanium alloy seamless tube prepared by a production method for improving the yield of titanium alloy seamless tubes as described in any one of claims 1-9.