A seamless titanium thermos cup welded pipe and production method

Abstract

The present invention discloses a production method of a seamless titanium thermos cup welded pipe, comprising step a forming and welding; step b scraping and finishing; step c sawing or cold drawing; step d cleaning and annealing, step a forming and welding: the forming roller extrude the titanium strip into shape, the high-frequency induction current rapidly heats the edge of the strip, and the extrusion roller extrude and welds the edge, step b scraping and finishing: the inner and outer scraping knives continuously scrape the weld slag extruded at the weld seam, and the finishing roller extrude and correct the roundness and straightness of the welded pipe, thereby obtaining a high-frequency induction welded titanium pipe, and step c sawing or cold drawing: the high-speed sawing machine follows the fixed length to cut the high-frequency induction welded titanium pipe. The seamless titanium thermos cup welded pipe produced by the present invention is a titanium welded pipe made of high-frequency induction welding, has high dimensional accuracy, good mechanical properties, and a production efficiency 10 times higher than that of seamless pipe making and argon arc welding pipe, realizing a rapid preparation process route of seamless titanium thermos cup pipes directly from raw material strips, greatly reducing production costs.

Description

Technical Field

[0001] The invention relates to the technical field of titanium welded pipes, in particular to a seamless titanium thermos cup welded pipe and a production method thereof. Background Art

[0002] Titanium metal has low density, light weight, high hardness, no rust, slow heat transfer, biophilicity, antibacterial and sterilization, and high-temperature oxidation coloring. Pure titanium thermos cups are beginning to be sought after by consumers. There are generally two ways to make thermos cups with pure titanium: titanium plate drawing and deformation and titanium tube water swelling. Titanium plate drawing and deformation has very high requirements on the consistency of the lateral and longitudinal elongation of the material, and the material loss is large, about 35%. Titanium tube water swelling can choose seamless titanium tube and welded titanium tube. Seamless titanium tube has many rolling and wall reduction processes and high cost. It is generally used to make thermos shells. Welded titanium tubes are made by fusion welding process. Because the weld grains are coarse, there is a significant color difference with the parent material. Even with vacuum electroplating, anodizing and surface sandblasting and other surface treatment processes, it is impossible to eliminate the weld and cover up the color difference. Therefore, it is generally only used for thermos liner. , since the microstructure and properties of the weld and heat-affected zone are significantly different from those of the parent material, the expansion rate during water swelling is generally not more than 25%, otherwise deformation and rupture will occur. When evacuating, due to the different properties and hardness of the weld, heat-affected zone and parent material, weld bulges and heat-affected zone depressions are likely to occur. Incomplete evacuation reduces the thermal insulation performance and shortens the thermal insulation time. Since the weld is a natural solidification connection after the molten pool is formed, pores and slag inclusions are prone to occur, resulting in a gradual decrease in vacuum and thermal insulation effects, and heat transfer cannot be isolated, causing the cup body to be hot. If the welded pipe annealing and cold rolling process is used for seamless treatment, compared with the seamless pipe, it loses the cost advantage. Therefore, whether it is the titanium plate drawing deformation or the seamless pipe and argon arc welding pipe water swelling forming, there are process limitations and cost pressures, which makes it difficult to mass-produce and popularize titanium insulation cups. Summary of the invention

[0003] In order to solve the problems raised in the above-mentioned background technology, the purpose of the present invention is to provide a seamless titanium insulation cup welded pipe and a production method, which has the advantages of high dimensional accuracy of the welded pipe, good mechanical properties, and greatly reduced production costs. It solves the problems of high processing cost, coarse weld grains, and obvious color difference with the parent material in the existing process. When vacuuming, due to the different properties and hardness of the weld, heat-affected zone, and parent material, weld bulges and heat-affected zone depressions are likely to occur, and pores and slag inclusions are likely to occur.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for producing a seamless titanium thermos cup welded pipe, comprising step a forming and welding; step b scraping and finishing; step c sawing or cold drawing; step d cleaning and annealing:

[0005] Step a: forming and welding: the forming roller extrude the titanium strip into shape, the high-frequency induction current rapidly heats the edge of the strip, and the extrusion roller extrude and welds the edge;

[0006] Step b: Scraping and finishing: The internal and external scraping knives continuously scrape the weld slag squeezed out of the weld seam, and the finishing roller squeezes and corrects the roundness and straightness of the welded pipe, thereby obtaining a high-frequency induction welded titanium pipe;

[0007] Step c: sawing or cold drawing: a high-speed sawing machine cuts the high-frequency induction welded titanium tube according to the fixed length. In order to save the mold manufacturing cost, welding mold change and debugging time, the high-frequency induction welded titanium tube off the line is shrunk, and the large-diameter high-frequency induction welded titanium tube is made into a cold-drawn reduced tube with a smaller diameter through a cold-drawn reduced diameter mold;

[0008] Step d: Cleaning and annealing: The cold-drawn reduced diameter tube is ultrasonically cleaned, inspected and dried by an ultrasonic cleaning machine, and sent to a channel vacuum induction furnace for annealing to ensure that the organization and performance of the original weld zone and heat-affected zone of the prepared seamless titanium welded tube are more consistent with the parent material. After annealing, a seamless titanium welded tube is obtained.

[0009] As a preferred embodiment of the present invention, the step a is formed and welded, the titanium strip coil is a TA1 or TA2 pure titanium coil, the hole types of the forming roller and the extrusion roller are planned according to the material properties, hardness, tube diameter, wall thickness, cold deformation stress, etc., and are made of superhard materials with poor affinity with the titanium element. The frequency and power of the high-frequency induced current, the welding extrusion amount of the extrusion roller, and the welding speed are adjusted according to the properties of the titanium element, the thickness of the titanium strip, the forming tube diameter, etc. The minimum welding speed is not less than 60m / min, so that the formed weld and the heat-affected zone are as narrow as possible.

[0010] As a preferred embodiment of the present invention, in step b of scraping and finishing, the welding slag is a thin linear protrusion formed by squeezing out the inner and outer shallow surface molten materials from the weld when the extrusion roller applies an upsetting force to the heated edge for welding. After removing the welding slag, the weld is a solid phase metal close to or equal to the base material.

[0011] As the preferred embodiment of the present invention, the step c is sawing or cold drawing, and the cold drawing is a cold drawing without reducing the wall and only using a cold drawing reduction outer mold. The common pipe diameters of titanium thermos cups are 45mm, 49mm, 51mm, 55mm, 57mm, 60mm, 65mm, 70mm, 80mm and 89mm, and the wall thickness is 0.5mm. Each pipe diameter is developed to form, weld and finish the mold, which requires too much investment, and the replacement and debugging of each specification of the mold takes a long time. Only two specifications of molds, 60mm and 89mm, are developed. Among them, the two pipe diameters of 60mm and 89mm do not need to be cold drawn, and they can be cleaned and annealed. It can be used. Five pipe diameters of 45mm, 49mm, 51mm, 55mm and 57mm can be cold-drawn and reduced from a 60mm diameter mother pipe. Three pipe diameters of 65mm, 70mm and 80mm can be cold-drawn and reduced from a 89mm diameter mother pipe. The welded pipe with a diameter difference of ≤30mm is cold-drawn and reduced in diameter by at least one pass, and the welded pipe with a diameter difference of ≥30mm is cold-drawn and reduced in diameter by at least two passes. During cold drawing, a special cold drawing medium is used which is modulated according to the characteristics of titanium element such as low density, high specific strength, poor ductility and low thermal conductivity. The maximum deformation of each pass does not exceed 36.5%, and the speed is 15 to 30m / minute.

[0012] As a preferred embodiment of the present invention, the step c is sawing or cold drawing, and the first cold drawing does not require annealing. Thereafter, when the deformation amount of each pass is greater than 30%, an intermediate annealing is added before the next cold drawing. When the deformation amount of each pass is less than 20%, one more cold drawing pass is added before annealing.

[0013] As a preferred embodiment of the present invention, in the step d of cleaning and annealing, the intermediate annealing is performed in an inert gas atmosphere at a temperature of 600-650° C. for a holding time of 5-10 min.

[0014] As a preferred embodiment of the present invention, the step d is cleaning and annealing, the ultrasonic cleaning is to dilute the commercially available heavy oil cleaning agent by 10 times, immerse the reduced diameter titanium welded pipe in the cleaning tank, heat it to 45-50°C and start the ultrasonic probe for cleaning for 20-30 minutes, dry the welded pipe that has passed the water pressure test, and during the vacuum annealing, the temperature is 600-650°C and the insulation time is 5-10min.

[0015] The present invention further protects a seamless titanium thermos cup welded pipe produced by the above production method.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The seamless titanium thermos cup welded pipe produced by the present invention is a titanium welded pipe made by high-frequency induction welding, wherein the two pipe diameters of 60mm and 89mm do not need cold drawing and can be used after cleaning and annealing, the five pipe diameters of 45mm, 49mm, 51mm, 55mm and 57mm60mm can be cold-drawn and reduced from the 60mm pipe diameter, and the three pipe diameters of 65mm, 70mm and 80mm can be cold-drawn and reduced from the 89mm pipe diameter. After at least one pass of cold drawing, reduction and annealing, the original weld seam on the appearance surface of the seamless titanium welded pipe is invisible, the wall thickness and outer diameter are uniform, the original weld seam and the heat-affected zone are in the length direction and the circumferential direction, and the organization and performance are consistent with the parent material. The production method is strip forming and welding, internal and external scraping and finishing, fixed-length sawing and cold drawing and reduction of welded pipes of non-online welding specifications, and finally cleaning and annealing.

[0018] 2. The seamless titanium welded pipe produced by the present invention has high dimensional accuracy and good mechanical properties. The production efficiency is more than 10 times higher than that of seamless pipe making and argon arc welded pipe. The process route of rapid preparation of seamless titanium insulation cup pipes directly from raw material strips is realized, which greatly reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the process of seamless titanium insulation cup welding pipe of the present invention;

[0020] Figure 2 It is a schematic diagram of the process flow of the diameter reduction cold drawing process of the seamless titanium thermos cup welded tube of the present invention.

[0021] In the figure: 1. Forming roller; 2. High-frequency induction current; 3. Extrusion roller; 4. Scraping knife; 5. Finishing roller; 6. Sawing machine; 7. High-frequency induction welding of titanium tube; 8. Welding seam; 9. Heat-affected zone; 10. Cold drawing reduction die; 11. Cold drawing reduction tube; 12. Ultrasonic cleaning machine; 13. Vacuum induction furnace; 14. Seamless titanium welded tube. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1-1:

[0024] like Figure 1 and Figure 2 As shown;

[0025] A seamless titanium thermos cup welded pipe is made by forming and welding, scraping and finishing, sawing, and then cold drawing, shrinking, cleaning and annealing of a non-online welding specification welded pipe after striping. The welded pipe is a high-frequency induction straight seam welded titanium pipe. The original weld seam of the prepared seamless titanium welded pipe is invisible on the surface, and the wall thickness and outer diameter are uniform. The original weld seam and heat-affected zone in the length direction and circumferential direction have the same organization and performance as the parent material, which is a polygonal equiaxial organization of uniform size.

[0026] The outer diameter of the seamless titanium welded pipe is 60mm, the wall thickness is 0.5mm, and the length is 2000mm;

[0027] The mother tube is a TA2 grade high frequency induction straight seam welded titanium tube with an outer diameter of 60mm, a wall thickness of 0.5mm and a length of 2000mm.

[0028] A method for producing a seamless titanium thermos cup welded pipe comprises the following steps: a) forming and welding; b) scraping and finishing; c) sawing or cold drawing; and d) cleaning and annealing:

[0029] Step a: forming and welding: the forming roller 1 extrude and form the titanium strip, the high-frequency induction current 2 rapidly heats the edge of the strip, and the extrusion roller 3 extrude and welds the edge;

[0030] Step b: scraping and finishing: the inner and outer scraping knives 4 continuously scrape the welding slag extruded from the weld 8 during the forming and welding in step a, and the finishing rollers 5 squeeze and correct the roundness and straightness of the welded pipe, thereby obtaining a high-frequency induction welded titanium pipe 7;

[0031] Step c: sawing or cold drawing: the high-speed sawing machine 6 cuts the high-frequency induction welded titanium tube 7 formed in step b through scraping and finishing to the required length, so as to save the mold manufacturing cost, welding mold change and debugging time;

[0032] Step d: Cleaning and annealing: The high-frequency induction welded titanium tube 7 is ultrasonically cleaned, inspected and dried by an ultrasonic cleaning machine 12, and sent to a channel vacuum induction furnace 13 for annealing to ensure that the structure and properties of the original weld seam 8 and the heat-affected zone 9 of the prepared seamless titanium welded tube 14 are more consistent with those of the parent material. After annealing, a seamless titanium welded tube 14 is obtained.

[0033] In step c of sawing or cold drawing, the present embodiment omits the cold drawing of reducing diameter;

[0034] During the cleaning and annealing in step d, the temperature is controlled at 600° C. and the holding time is 5 minutes.

[0035] The seamless titanium thermos cup welded pipe 14 prepared through the above steps only needs 0.005mm deep polishing, the original weld 8 is invisible on the surface, the wall thickness and outer diameter are uniform, and the original weld 8 and the heat affected zone 9 are consistent with the parent material in the length direction and the circumferential direction. Its organization and performance are uniformly sized polygonal equiaxial organization, with high dimensional accuracy and good mechanical properties. The production efficiency is more than 10 times higher than that of seamless pipe making and argon arc welding pipe, realizing the process route of rapid preparation of seamless titanium thermos cup pipes directly from raw material strips, which greatly reduces the production cost.

[0036] Embodiment 1-2:

[0037] like Figure 1 and Figure 2 As shown;

[0038] A seamless titanium thermos cup welded pipe is made by forming and welding, scraping and finishing, sawing, and then cold drawing, shrinking, cleaning and annealing of a non-online welding specification welded pipe after striping. The welded pipe is a high-frequency induction straight seam welded titanium pipe. The original weld seam of the prepared seamless titanium welded pipe is invisible on the surface, and the wall thickness and outer diameter are uniform. The original weld seam and heat-affected zone in the length direction and circumferential direction have the same organization and performance as the parent material, which is a polygonal equiaxial organization of uniform size.

[0039] The seamless titanium welded pipe 14 has an outer diameter of 57 mm, a wall thickness of 0.5 mm, and a length of 2000 mm, and is a reduced diameter seamless titanium welded pipe;

[0040] The high-frequency induction welded titanium tube 7 is a TA2-grade high-frequency induction straight seam welded titanium tube with an outer diameter of 60 mm, a wall thickness of 0.5 mm, and a length of 2000 mm.

[0041] In step c, the sawing or cold drawing is performed at a speed of 15-30 m / min, the outer diameter reduction die used is made of cemented carbide, and the cold drawing medium used has sufficient viscosity and lubricity and can form a protective oil film on the surface of the titanium tube;

[0042] In step c, the maximum reduction rate of each cold drawing pass is no more than 36.5%;

[0043] In step c, sawing or cold drawing, the first pass does not require annealing. When the diameter change of each pass is greater than 30%, an intermediate annealing is added between each cold drawing pass. When the diameter change of each pass is less than 30%, one more pass is added before annealing.

[0044] This embodiment is a one-step reduction cold drawing, using a reduction outer die with an outer diameter of 57 mm to obtain a seamless titanium welded tube 14 with an outer diameter of 57 mm, a wall thickness of 0.5 mm, and a length of 2000 mm.

[0045] The remaining steps of this embodiment are the same as those of embodiment 1-1

[0046] Example 2-1:

[0047] like Figure 1 and Figure 2 As shown;

[0048] A seamless titanium thermos cup welded pipe is made by forming and welding, scraping and finishing, sawing, and then cold drawing, shrinking, cleaning and annealing of a non-online welding specification welded pipe after striping. The welded pipe is a high-frequency induction straight seam welded titanium pipe. The original weld seam of the prepared seamless titanium welded pipe is invisible on the surface, and the wall thickness and outer diameter are uniform. The original weld seam and heat-affected zone in the length direction and circumferential direction have the same organization and performance as the parent material, which is a polygonal equiaxial organization of uniform size.

[0049] The seamless titanium welded pipe 14 has an outer diameter of 70 mm, a wall thickness of 0.5 mm, and a length of 2000 mm, and is a reduced diameter seamless titanium welded pipe.

[0050] The high-frequency induction welded titanium tube 7 uses a TA1 high-frequency induction straight seam welded titanium tube with an outer diameter of 89 mm, a wall thickness of 0.5 mm, and a length of 2000 mm.

[0051] This embodiment is a one-step shrinkage cold drawing, using a shrinkage outer die with an outer diameter of 70 mm, and after shrinkage cold drawing, a seamless titanium welded pipe 14 with an outer diameter of 70 mm, a wall thickness of 0.5 mm, and a length of 2000 mm is obtained;

[0052] During the cleaning and annealing in step d, the temperature is controlled at 600° C. and the holding time is 6 minutes.

[0053] The remaining steps of this embodiment are the same as those of embodiment 1-1.

[0054] Example 2-2:

[0055] like Figure 1 and Figure 2 As shown;

[0056] The remaining steps of this embodiment remain unchanged. The outer diameter of the seamless titanium welded tube 14 is 65 mm, the wall thickness is 0.5 mm, and the length is 2000 mm. It is a reduced diameter seamless titanium welded tube.

[0057] The high-frequency induction welded titanium tube 7 adopts the unannealed TA1 high-frequency induction straight seam welded titanium tube obtained in Example 2-1 with an outer diameter of 70 mm, a wall thickness of 0.5 mm, and a length of 2000 mm.

[0058] This embodiment is a one-step shrinkage cold drawing, using a shrinkage outer die with an outer diameter of 70 mm, and after shrinkage cold drawing, a seamless titanium welded tube 14 with an outer diameter of 65 mm, a wall thickness of 0.5 mm, and a length of 2000 mm is obtained;

[0059] The remaining steps of this embodiment are the same as those of embodiment 1-1.

[0060] Comparative Example:

[0061] The 60mm diameter seamless titanium welded pipe without reduced diameter obtained in Example 1-1, the 57mm diameter seamless titanium welded pipe with reduced diameter obtained in Example 1-2, the 70mm diameter seamless titanium welded pipe obtained in Example 2-1 and the 65mm diameter seamless titanium welded pipe with reduced diameter obtained in Example 2-2 were commissioned to a thermos cup factory to be made into titanium thermos cups, wherein the 60mm diameter was used as the outer shell and the 57mm diameter was used as the liner to make a 350ml titanium thermos cup, and the 70mm diameter was used as the outer shell and the 65mm diameter was used as the liner to make a 450ml titanium thermos cup, which were compared with the following titanium thermos cups with the same material, specification, capacity and sealing:

[0062] Comparative Example 1-1: The outer shell is 60 mm × 0.5 mm, the inner shell is 57 mm × 0.5 mm, and both use TA2 seamless titanium tubes;

[0063] Comparative Example 1-2: The outer shell is 60mm×0.5mm, using TA2 seamless titanium tube, and the inner liner is 57mm×0.5mm, using TA2 argon arc welded titanium tube;

[0064] Comparative Example 1-3: The outer shell is 60mm×0.5mm, the inner shell is 57mm×0.5mm, and both use TA2 argon arc welding titanium pipe;

[0065] Comparative Example 2-1: The outer shell is 70 mm × 0.5 mm, the inner shell is 65 mm × 0.5 mm, and both use TA1 seamless titanium tubes;

[0066] Comparative Example 2-2: The outer shell is 70mm×0.5mm, using TA1 seamless titanium welded tube, and the inner liner is 65mm×0.5mm, using TA1 argon arc welded titanium tube;

[0067] Comparative Example 2-3: outer shell 70mm×0.5mm, liner 65mm×0.5mm, both using TA1 argon arc welding titanium tube;

[0068] The comparison results are shown in Table 1.

[0069]

[0070] Table 1

[0071] In the above table, the heat preservation conditions are filled with 95℃ boiling water, the ambient temperature is 20℃, and the heat preservation time is 8 hours; the cold preservation conditions are filled with 0℃ ice water, the ambient temperature is 20℃, and the cold preservation time is 8 hours.

[0072] As can be seen from the above table, the high-frequency induction seamless titanium insulation cup welded pipe prepared by the present invention has good performance, and the expansion rate and vacuum degree after vacuuming are comparable to those of seamless titanium pipes. The thermal insulation and cold preservation performance of the titanium insulation cup prepared is the same as that of seamless titanium pipes, but the expansion rate of the argon arc welded pipe is low, and the heat-affected zone is prone to depression during vacuuming, and the vacuum degree and thermal insulation and cold preservation effects are significantly lower than those of high-frequency induction seamless titanium welded pipes and seamless titanium pipes;

[0073] The high-frequency induction seamless titanium welded pipe obtained in Example 1-1 is not cold-drawn after diameter reduction, and the expansion rate of the high-frequency induction seamless titanium welded pipe and the seamless titanium pipe obtained in Example 1-2 after diameter reduction and cold drawing is equivalent, and the expansion rate is increased by more than 60% compared with the argon arc welded pipe;

[0074] The expansion rate of the high-frequency induction seamless titanium welded pipe obtained by one-pass cold-drawing of Example 2-1 and two-pass cold-drawing of Example 2-2 is basically the same as that of the seamless titanium pipe, and the expansion rate is increased by more than 58% compared with the argon arc welded pipe;

[0075] Examples 1-1, 1-2 and Comparative Examples 1-1, 1-2, 1-3 are all TA2 pure titanium, and Examples 2-1, 2-2 and Comparative Examples 2-1, 2-2, 2-3 are all TA1 pure titanium. Since TA1 pure titanium has higher purity and increased ductility than TA2 pure titanium, the expansion rate is relatively increased;

[0076] The heat preservation and cooling effects of a thermos cup are also affected by its capacity, so the 450ml thermos cup in the above table has better heat preservation and cooling effects than the 350ml thermos cup.

[0077] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0078] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing a seamless titanium insulation cup welded pipe, characterized in that: The method comprises the steps of a) forming and welding; b) scraping and finishing; c) sawing and cold drawing; and d) cleaning and annealing. Step a) forming and welding: the forming roller (1) extrude and form the titanium strip, the high-frequency induction current (2) rapidly heats the edge of the strip, and the extrusion roller (3) extrude and welds the edge, the titanium strip being a TA1 or TA2 pure titanium strip, the hole patterns of the forming roller (1) and the extrusion roller (3) are planned according to the material properties, hardness, tube diameter, wall thickness, and cold deformation stress, and are made of a superhard material with poor affinity with the titanium element, the frequency and power of the high-frequency induction current (2), the welding extrusion amount of the extrusion roller (3), and the welding speed are adjusted according to the properties of the titanium element, the thickness of the titanium strip, and the forming tube diameter, and the minimum welding speed is not less than 60 m / min; Step b) scraping and finishing: the inner and outer scraping knives (4) continuously scrape the weld slag extruded from the weld seam (8), and the finishing rollers (5) squeeze and correct the roundness and straightness of the welded pipe, thereby obtaining a high-frequency induction welded titanium pipe (7). After removing the weld slag, the weld seam (8) is a solid phase metal close to or the same as the base material; Step c) sawing and cold drawing: a high-speed sawing machine (6) follows the cut-to-length high-frequency induction welded titanium tube (7), and after the head of the offline high-frequency induction welded titanium tube (7) is shrunk, the large-diameter high-frequency induction welded titanium tube (7) is made into a small-diameter cold-drawn reduced-diameter tube (11) through a cold-drawn reduced-diameter die (10). The cold-drawing is a reduced-diameter cold-drawn tube without wall reduction and only using a cold-drawn reduced-diameter die. The diameters of the titanium thermos cups are 45mm, 49mm, 51mm, 55mm, 57mm, 60mm, 65mm, 70mm, 80mm and 89mm, and the wall thickness is 0.5mm. Two specifications of molds are developed, 60mm and 89mm. Among them, the two diameters of 60mm and 89mm do not need cold drawing and can be used after cleaning and annealing. The diameters of 45mm, 49mm, 51mm, 55mm and 57mm Five pipe diameters can be cold-drawn and reduced from a 60mm diameter mother pipe, and three pipe diameters of 65mm, 70mm, and 80mm can be cold-drawn and reduced from an 89mm diameter mother pipe. The welded pipe with a diameter difference of ≤30mm is cold-drawn and reduced in diameter by at least one pass, and the welded pipe with a diameter difference of ≥30mm is cold-drawn and reduced in diameter by at least two passes. Cold drawing medium is used during cold drawing, and the maximum deformation of each pass does not exceed 36.5%, and the speed is 15-30m / min. Annealing is not required for the first cold drawing pass. After that, when the deformation of each pass is greater than 30%, an intermediate annealing is added before the cold drawing again. When the deformation of each pass is less than 20%, one more cold drawing pass is added before annealing. The intermediate annealing is annealing in an inert gas atmosphere at a temperature of 600-650°C and a holding time of 5-10min. Step d) cleaning and annealing: The cold-drawn reduced diameter tube (11) is ultrasonically cleaned, tested and dried by an ultrasonic cleaning machine (12), and then sent to a channel-type vacuum induction furnace (13) for annealing to ensure that the structure and properties of the original weld seam (8) area and the heat-affected zone (9) of the prepared seamless titanium welded tube (14) are consistent with those of the parent material. After annealing, a seamless titanium welded tube (14) is obtained. During the vacuum annealing, the temperature is 600-650° C. and the holding time is 5-10 minutes.

2. The seamless titanium thermos cup welded pipe produced by the production method according to claim 1.

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