Vacuum cup with titanium inside and stainless steel outside and manufacturing method thereof

Abstract

According to the vacuum cup with the titanium inside and the stainless steel outside and the manufacturing method of the vacuum cup, the structure of an existing vacuum cup is improved, a titanium material and a stainless steel material are welded through electromagnetic pulse welding, high-strength combination between a titanium cup opening and a stainless steel cylinder is achieved, reliable welding is formed under the condition that lap joint at the position of a welding spot is very short, and the welding quality is improved. The welding seam strength is larger than 300 Mpa, and the welding yield can reach 98% or above.

Description

Technical Field

[0001] The invention belongs to the field of vacuum insulation containers, and in particular relates to a vacuum insulation cup with titanium inside and stainless steel outside and a manufacturing method thereof. Background Art

[0002] At present, the most common structure of titanium thermos cup is titanium liner + outer stainless steel shell, but because the titanium liner and stainless steel shell are welded

[0003] During the process, there are large differences in melting point, thermal conductivity, expansion coefficient, etc., which will lead to uneven heating of the weld or excessive residual stress. At the same time, under high temperature, titanium is easy to react with oxygen and nitrogen in the air to affect the stability of the weld, and it is also easy to combine with C, Cr, and Ni in stainless steel to form hard and brittle metal compounds, which reduce the plasticity of the joint, increase brittleness, and cause cracks or pores in the weld; therefore, the conventional low-cost fusion welding (argon arc welding, laser welding, etc.) has a very low welding yield, there are hidden dangers in use, and greatly increase the manufacturing cost of the product.

[0004] At present, vacuum brazing is one of the few welding processes that can be used for thermos cups with titanium inside and stainless steel outside. During the welding process, the titanium inner liner and the stainless steel outer shell thermos cup are placed in a vacuum furnace for high-temperature welding. However, this mode takes up more space in the vacuum furnace and the welding time is as long as several hours, resulting in very low production capacity and high energy consumption. Therefore, it is particularly important to improve the welding process.

[0005] Electromagnetic pulse welding is a new type of room temperature solid state pressure welding technology. Compared with melting welding and vacuum brazing, its welding time is very short, energy consumption is extremely low, and the metal to be welded is usually not melted, which reduces or even inhibits the formation of intermetallic compounds and better ensures the quality of the welded joint. Therefore, it can be used as an alternative welding method for welding titanium and stainless steel in a thermos cup with titanium inside and stainless steel outside. At the same time, in order to ensure the smooth progress of this welding method, the existing thermos cup structure needs to be improved. Summary of the invention

[0006] In view of this, the present invention aims to propose a thermos cup with titanium inside and stainless steel outside and a manufacturing method thereof, which can weld two materials with a wall thickness of only 0.5 mm, and form a reliable weld with a very short overlap at the welding point. The tensile strength of the weld can reach more than 300 MPa, which meets product requirements and solves the problems of low production capacity and high energy consumption of the existing vacuum brazing process.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A thermos cup with titanium inside and stainless steel outside comprises a titanium liner and a stainless steel shell sleeved on the outside of the titanium liner, a vacuum layer is formed between the titanium liner and the stainless steel shell, the stainless steel shell comprises a titanium cup mouth, a stainless steel cylinder and a stainless steel base which are arranged in sequence from top to bottom, and the wall thickness of the titanium cup mouth, the stainless steel cylinder and the stainless steel base is 0.5-0.6mm; the diameter of the titanium cup mouth 5-7mm away from the lower end of the titanium cup mouth gradually increases so as to overlap the outer side of the upper end of the stainless steel cylinder; a step with a height difference of 0.5-0.6mm is formed 5-7mm away from the upper end of the stainless steel cylinder so as to overlap the titanium cup mouth at the step; the edge of the stainless steel base also forms a step with a height difference of 0.5-0.6mm so as to overlap the lower end of the stainless steel cylinder at the step; the titanium cup mouth and the stainless steel cylinder are welded by electromagnetic pulse welding, and the cup mouth of the titanium liner and the titanium cup mouth are welded by laser welding.

[0009] Furthermore, the radius of the lower end of the titanium cup mouth gradually increases so that the side wall of the lower end of the titanium cup mouth tilts outwards with an inclination angle of 5°.

[0010] Furthermore, the cup mouth of the titanium liner is folded outward to form a flange, and the flange is welded to the titanium cup mouth.

[0011] The present invention also provides a method for manufacturing the above-mentioned thermos cup with titanium inside and stainless steel outside, the method comprising the following steps:

[0012] S1, process the titanium liner, titanium cup mouth, stainless steel cylinder and stainless steel base respectively;

[0013] S2. A mandrel is processed according to the shape of the stainless steel shell to locate and block the movement of the stainless steel shell. A step of 0.65-0.75 mm is provided at the joint between the titanium cup mouth and the stainless steel cylinder.

[0014] S3, process the copper impact ring used to cover the titanium cup mouth and the stainless steel cylinder welding part, with a thickness of 1mm and a width of 5-7mm;

[0015] S4. Assemble the titanium cup mouth and the stainless steel cylinder: insert the mandrel into the stainless steel cylinder, and then assemble the titanium cup mouth with the stainless steel cylinder and the mandrel. The overlap position of the titanium cup mouth and the stainless steel cylinder is not in direct contact, and the spacing is 1-2mm;

[0016] S5. Put the copper impact ring on the welding position of the titanium cup mouth and the stainless steel cylinder, and the copper impact ring and the titanium cup mouth are in contact with each other, and can be fixed with double-sided tape; then fix the magnetic induction coil around the welding position of the titanium cup mouth and the stainless steel cylinder to perform electromagnetic pulse welding;

[0017] S6. Welding the entire shell: insert the socket of the stainless steel base into the shell part welded in step S5, then place it on the welding tool, and use a fiber optic continuous laser welding machine to complete the welding;

[0018] S7, welding the titanium liner: put the stainless steel shell welded in step S6 into the contour welding tooling to fix it, assemble the titanium liner and the stainless steel shell, and then use the top pressing tooling to tightly fit the two parts, and finally use the fiber optic continuous laser welding machine to complete the welding;

[0019] S8. Completely evacuate the space between the titanium liner and the stainless steel shell, and complete the sealing welding of the vacuum hole on the stainless steel base.

[0020] Further, the specific steps of S1 are:

[0021] S11, Processing titanium liner:

[0022] Using pure titanium as the material, the expansion wave machine is processed into the inner liner;

[0023] S12, Processing Titanium Cup Mouth:

[0024] Use pure titanium as the material and process it into a titanium cup mouth;

[0025] S13, Processing of stainless steel cylinder:

[0026] Use a 0.5mm thick stainless steel plate, process it into the specified size, and form it into a cylindrical shape through rolling + TIG welding. Then use the equipment to complete the specific shape of the cup body. Use a rolling machine to make one end of the stainless steel cylinder into a stepped shape with a step height difference of 0.5-0.6mm, which will be used to match the titanium cup mouth later.

[0027] S14, Processing of stainless steel base:

[0028] Use a stainless steel disc to stretch it into the shape of the shell base, and use a rolling machine to form a stepped shape on one end of the base edge with a step height difference of 0.5-0.6mm. It is then used to cooperate with the stainless steel cylinder. Finally, a cutting machine is used to cut off the excess part to ensure the final size of the base.

[0029] Furthermore, before assembling in step S4, the weld surfaces of the two metal materials need to be polished and then cleaned with alcohol.

[0030] Further, in step S5, the parameters of electromagnetic pulse welding are: discharge voltage is 20-27KV, pulse frequency is 20-23KHZ, duration of high-speed pulse is 45-55μs; the welding joint should be located at the center of the coil to ensure the best welding effect.

[0031] Further, in step S6, the welding joint is in the form of a butt joint, and the specific welding parameters are: focal length +1, welding power 1300-1350W, laser core diameter 500μm, welding speed 200-300mm / min; the laser beam is controlled to align with the middle position of the weld to maximize the weld quality.

[0032] Further, in step S7, the welding joint is in the form of a lap joint, and the specific welding parameters are: focal length +1, welding power 950-1050W, laser core diameter 500μm, welding speed 200-250mm / min; the laser beam position is controlled to be biased toward the upper titanium plate position with an offset of 0.2mm.

[0033] Further, in step S8, the vacuuming method is as follows: placing the spherical glass solder into the vacuum hole on the stainless steel base, placing the spherical glass solder into a vacuum furnace in batches, and setting the gas pressure to 10 -4 Pa, the temperature reaches 700℃-800℃, and the space between the inner tank and the outer shell is completely vacuumed.

[0034] Furthermore, after completing all the processes, all the weld positions are placed in an automatic polishing machine for polishing to remove the surface oxidation color.

[0035] Compared with the prior art, the titanium-inner and stainless-steel-outer thermos cup and the manufacturing method thereof of the present invention have the following advantages:

[0036] (1) The titanium inner and stainless steel outer thermos cup of the present invention is welded to the titanium material and the stainless steel material by electromagnetic pulse welding, thereby achieving a high-strength bond between the titanium cup mouth and the stainless steel cylinder. The weld strength is greater than 340Mpa, and the welding yield rate can reach more than 98%. At present, the vacuum brazing yield rate is about 90%.

[0037] (2) The welding process of the manufacturing method of the thermos cup with titanium inside and stainless steel outside described in the present invention does not require gas protection, welding materials, and the cost of consumables is extremely low (up to millions of times). The power consumption is low, and the comprehensive cost is 0.8 yuan / joint. However, the cost of vacuum brazing is as high as 6 yuan / joint due to power consumption and brazing materials.

[0038] (3) The manufacturing method of the thermos cup with titanium inside and stainless steel outside of the present invention is easy to realize automation, has low requirements on operators, and the whole process is free of any water, gas, radiation and other pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0040] Figure 1 This is a schematic diagram of a thermos cup with titanium inside and stainless steel outside according to an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of a titanium liner according to an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the cup mouth of a titanium housing according to an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of a stainless steel outer shell cylinder according to an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram of a stainless steel housing base according to an embodiment of the present invention;

[0045] Figure 6 This is a schematic diagram of the stainless steel shell cylinder + titanium shell cup after welding according to an embodiment of the present invention;

[0046] Figure 7 A schematic diagram of a mandrel for electromagnetic pulse welding according to an embodiment of the present invention;

[0047] Figure 8 This is a schematic diagram of the welding of the stainless steel shell cylinder + titanium shell cup according to an embodiment of the present invention;

[0048] Fig. 9 This is a schematic diagram of welding at other positions of the thermos cup according to an embodiment of the present invention;

[0049] Fig.10 This is the tensile strength test diagram of pure titanium TA1 plate and 304 stainless steel plate after welding;

[0050] Fig.11 This is the SEM morphology of the electromagnetic pulse welding fusion zone;

[0051] Fig.12 Line scanning energy spectrum analysis of electromagnetic pulse welding fusion zone.

[0052] Description of reference numerals:

[0053] 1. Titanium liner; 11. Flanging; 2. Stainless steel shell; 21. Titanium cup mouth; 22. Stainless steel cylinder; 23. Stainless steel base; 3. Core rod; 4. Copper impact ring; 5. Magnetic induction coil; 6. Cup mouth welding position; 7. Cup bottom welding position. DETAILED DESCRIPTION

[0054] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0055] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0056] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0057] Example 1

[0058] like Figure 1 This is a schematic diagram of a thermos cup with titanium inside and stainless steel outside manufactured by the present invention.

[0059] The manufacturing method of the thermos cup with titanium inside and stainless steel outside of the present invention comprises the following steps:

[0060] S1. Process the titanium liner 1, the titanium cup mouth 21, the stainless steel cylinder 22 and the stainless steel base 23 respectively.

[0061] S11, Processing titanium liner:

[0062] Pure titanium (TA1) is used as the material, and the inner liner is processed by a wave forming machine; the cup mouth of the titanium inner liner is folded outward to form a flange 11, and the flange is used for welding with the titanium cup mouth; the structure is as follows Figure 2 shown.

[0063] S12, Processing titanium cup mouth:

[0064] Pure titanium (TA1) is used as the material to process the titanium cup mouth with a wall thickness of 0.5mm. The diameter of the titanium cup mouth at 6mm from the lower end gradually increases to facilitate the overlap with the outer side of the upper end of the stainless steel cylinder. In addition, the lower end of the titanium cup mouth is inclined outward due to the gradually increasing radius, and the inclination angle is 5°. Figure 3 shown.

[0065] S13, Processing of stainless steel cylinder:

[0066] Use 0.5mm thick stainless steel plate 304, process it into the specified size, and form it into a cylindrical shape through rolling + TIG welding. Then use the equipment to complete the specific shape of the cup body. Use a rolling machine to form a step shape at one end of the stainless steel cylinder 6mm away from the end. The step height difference is 0.5mm, which is subsequently used to match the titanium cup mouth; the structure is as follows Figure 4 shown.

[0067] S14, Processing of stainless steel base:

[0068] Use stainless steel 304 discs, stretch them into the shape of the shell base, and use a rolling machine to form a stepped shape on one end of the base edge, with a step height difference of 0.5mm. It will then be used to match the stainless steel cylinder, and finally use a cutting machine to cut off the excess part to ensure the final size of the base. Figure 5 shown.

[0069] S2, according to the shape of the stainless steel shell 2, the core rod 3 is processed to locate and block the movement of the stainless steel shell. The core rod is provided with a 0.72mm step at the joint between the titanium cup mouth and the stainless steel cylinder. The core rod is made of 45 steel and has a structure as shown in FIG. Figure 7 shown.

[0070] S3. Process a copper impact ring 4 for sleeve on the titanium cup mouth and the stainless steel cylinder welding position, with a thickness of 1mm and a width of 6mm. The copper impact ring and the titanium cup mouth can be fixed with double-sided tape to make the two contact with each other, which can ensure that the copper impact ring will not be welded to the titanium cup mouth. After welding, it is convenient to remove the copper impact ring.

[0071] The copper impact ring is used because the resistivity of metal titanium and its alloy is large, and the kinetic energy generated in the alternating electric field is small. Placing a copper impact ring on the surface of the welding part helps welding. The material is soft copper.

[0072] S4. Preparation before assembly: Before assembly, the weld surface of the two metal materials needs to be polished and cleaned with alcohol.

[0073] S5. Assemble the titanium cup mouth and the stainless steel cylinder: insert the mandrel into the stainless steel cylinder to resist the impact during welding and ensure that the shape of the cup body remains unchanged. Then assemble the titanium cup mouth with the stainless steel cylinder and the mandrel. The joint form is as follows: Figure 8 As shown, the overlap position of the titanium cup mouth and the stainless steel cylinder is not in direct contact, with a spacing of 1-2mm; the overlap method of the welding position does not require the workpieces to contact each other, reducing deformation and thermal effects during welding, ensuring reliable welding, and leaving enough distance to convert electrical energy into kinetic energy.

[0074] S6, such as Figure 8 , put the copper impact ring on the welding position of the titanium cup mouth and the stainless steel cylinder, and then fix the magnetic induction coil 5 around the welding position of the titanium cup mouth and the stainless steel cylinder to perform electromagnetic pulse welding;

[0075] Joint form: 1-2mm gap between two parts (titanium plate tilted);

[0076] The specific welding parameters are: adjust the electromagnetic pulse welding equipment to a discharge voltage of 23KV, a pulse frequency of 20KHZ, and a high-speed pulse duration of 50μs.

[0077] The welding joint should be located in the center of the coil to ensure the best welding effect.

[0078] S7, welding shell as a whole: according to Fig. 9 , insert the socket of the stainless steel base into the shell part welded in step S6, then place it on the welding tool, and use a fiber optic continuous laser welding machine to complete the welding at the cup bottom welding position 7;

[0079] Joint form: butt joint (with built-in gasket), specific welding parameters are: focal length +1, welding power 1300W, laser core diameter 500μm, welding speed 250mm / min;

[0080] Precisely control the position of the laser beam to align it with the center of the weld to maximize weld quality.

[0081] S8, welding titanium liner: according to Fig. 9 , put the stainless steel shell welded in step S7 into the contour welding tooling to fix it, assemble the titanium liner and the stainless steel shell, and then use the top pressing tooling to tightly fit the two parts, and finally use the optical fiber continuous laser welding machine to complete the welding at the cup mouth welding position 6;

[0082] Joint form: lap joint. Specific welding parameters are: focal length +1, welding power 1000W, laser core diameter 500μm, welding speed 210mm / min;

[0083] The position of the laser beam is precisely controlled so that it is biased toward the upper titanium plate with an offset of about 0.2 mm, which can improve the yield.

[0084] S9, vacuuming and welding: put the spherical glass solder into the vacuum hole on the stainless steel base, and put them into the vacuum furnace in batches, set the gas pressure to 10-4Pa, the temperature to 800℃, thoroughly vacuum the space between the inner tank and the outer shell, and complete the sealing welding of the vacuum hole on the stainless steel base.

[0085] S10. After completing all the processes, place all the weld positions on the automatic polishing machine for polishing to remove the surface oxidation color.

[0086] Experiment 1: Selection of electromagnetic pulse welding parameters

[0087] In order to determine the optimal parameters of electromagnetic pulse welding, welding experiments were carried out at different discharge voltages and pulse frequencies.

[0088] When the pulse frequency is 20KHZ, the voltages of 18KV, 20KV, 23KV, 25KV, 27KV and 29KV are selected to weld the titanium cup mouth and the stainless steel cylinder respectively; when the voltage is 23KV, the pulse frequencies of 18KHZ, 20KHZ, 23KHZ and 25KHZ are selected to weld the titanium cup mouth and the stainless steel cylinder respectively.

[0089] The results showed that when the voltage was less than 20KV, the energy was insufficient and welding could not be achieved; when the voltage was greater than 27KV, the material might partially melt and re-solidify, which would result in a weak weld.

[0090] When the pulse frequency is less than 20KHZ, the energy is insufficient and welding cannot be achieved; when the pulse frequency is greater than 23KHZ, the material may also partially melt and re-solidify, which will result in a loose weld.

[0091] It shows that when welding the titanium cup mouth and the stainless steel cylinder, the discharge voltage and pulse frequency must be kept within a specific range to achieve the best welding effect.

[0092] Test example:

[0093] 1. In order to verify the welding effect of the titanium cup mouth and the stainless steel cylinder, pure titanium TA1 plate and 304 stainless steel plate from the same batch of materials used to manufacture the titanium cup mouth and stainless steel cylinder of the thermos cup were selected for experiments, and a total of 50 groups of experiments were conducted.

[0094] During the experiment, it was also ensured that the pure titanium TA1 plate and the 304 stainless steel plate did not touch each other, with a spacing of 1-2 mm. A copper plate of the same material and thickness as the copper impact ring was attached to the outside of the pure titanium TA1 plate. Then, the magnetic induction coil was fixed around the welding positions of the pure titanium TA1 plate and the 304 stainless steel plate for electromagnetic pulse welding. The welding parameters were the same as the above parameters.

[0095] Finally, the tensile strength test of the welded materials was carried out. Only one of the 50 welded samples was defective, and the pass rate reached 98%. The results are as follows: Fig.10 As shown in the figure, two groups of test results were randomly selected from qualified samples. It can be seen that the fracture occurred in the titanium plate and the tensile strength of the weld was greater than 300Mpa.

[0096] 2. Microscopic analysis of the weld. Fig.11 This is the SEM morphology of the electromagnetic pulse welding fusion zone; Fig.12 Line scanning energy spectrum analysis of electromagnetic pulse welding fusion zone.

[0097] During electromagnetic pulse welding, high plastic deformation as well as high shear strain and oxide damage occur due to the high temperatures near the jet and collision zone (much lower than the melting point of the material). This leads to solid-state welding due to the refinement of the microstructure, dislocation units, slip bending, microtwins and local recrystallization.

[0098] Fig.12 In the figure, the left side is 304 stainless steel, which is mainly composed of Fe and Cr, and the right side is pure titanium TA1, which is mainly composed of Ti and C. At the fusion site, Fe gradually decreases and Ti gradually increases, indicating that under the action of electromagnetic pulse welding, Fe and Ti diffuse, thereby realizing the welding of titanium material and stainless steel material.

[0099] In addition, the existence of supersaturated β-Ti(Fe) solid solution is a prerequisite for the formation of hard and brittle Ti-Fe compounds (TiFe, TiFe2, Ti2Fe). The large-scale formation of supersaturated β-Ti(Fe) solid solution requires a temperature of >1100°C and a holding time of >10s. The temperature of electromagnetic pulse welding generally does not exceed 600°C, so it will not produce more hard and brittle Ti-Fe compounds. This is one of the reasons why its weld strength is greater than that of the base material (TA1).

[0100] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A thermos cup with titanium inside and stainless steel outside, characterized by: It includes a titanium liner and a stainless steel shell sleeved on the outside of the titanium liner, a vacuum layer is formed between the titanium liner and the stainless steel shell, the stainless steel shell includes a titanium cup mouth, a stainless steel cylinder and a stainless steel base arranged in sequence from top to bottom, and the wall thickness of the titanium cup mouth, the stainless steel cylinder and the stainless steel base is 0.5-0.6mm; the diameter of the titanium cup mouth 5-7mm away from the lower end of the titanium cup mouth gradually increases to facilitate overlapping on the outer side of the upper end of the stainless steel cylinder; a step with a height difference of 0.5-0.6mm is formed 5-7mm away from the upper end of the stainless steel cylinder to facilitate overlapping of the titanium cup mouth at the step; the edge of the stainless steel base also forms a step with a height difference of 0.5-0.6mm to facilitate overlapping of the lower end of the stainless steel cylinder at the step; the titanium cup mouth and the stainless steel cylinder are welded by electromagnetic pulse welding, and the cup mouth of the titanium liner and the titanium cup mouth are welded by laser welding.

2. The thermos cup with titanium inside and stainless steel outside according to claim 1, characterized in that: The radius of the lower end of the titanium cup mouth gradually increases, so that the side wall of the lower end of the titanium cup mouth tilts outward, and the tilt angle is 5°.

3. The thermos cup with titanium inside and stainless steel outside according to claim 1, characterized in that: The cup mouth of the titanium liner is folded outward to form a flange, and the flange is welded to the titanium cup mouth.

4. A method for manufacturing a thermos cup with titanium inside and stainless steel outside as claimed in any one of claims 1 to 3, characterized in that: The method comprises the following steps: S1, process the titanium liner, titanium cup mouth, stainless steel cylinder and stainless steel base respectively; S2. A mandrel is processed according to the shape of the stainless steel shell to locate and block the movement of the stainless steel shell. A step of 0.65-0.75 mm is provided at the joint between the titanium cup mouth and the stainless steel cylinder. S3, process the copper impact ring used to cover the titanium cup mouth and the stainless steel cylinder welding part, with a thickness of 1mm and a width of 5-7mm; S4. Assemble the titanium cup mouth and the stainless steel cylinder: insert the mandrel into the stainless steel cylinder, and then assemble the titanium cup mouth with the stainless steel cylinder and the mandrel. The overlap position of the titanium cup mouth and the stainless steel cylinder is not in direct contact, and the spacing is 1-2mm; S5, putting the copper impact ring on the welding position of the titanium cup mouth and the stainless steel cylinder, and the copper impact ring and the titanium cup mouth are in contact with each other; then fixing the magnetic induction coil around the welding position of the titanium cup mouth and the stainless steel cylinder to perform electromagnetic pulse welding; S6. Welding the entire shell: insert the socket of the stainless steel base into the shell part welded in step S5, then place it on the welding tool, and use a fiber optic continuous laser welding machine to complete the welding; S7, welding the titanium liner: put the stainless steel shell welded in step S6 into the contour welding tooling to fix it, assemble the titanium liner and the stainless steel shell, and then use the top pressing tooling to tightly fit the two parts, and finally use the fiber optic continuous laser welding machine to complete the welding; S8. Completely evacuate the space between the titanium liner and the stainless steel shell, and complete the sealing welding of the vacuum hole on the stainless steel base.

5. The method for manufacturing a thermos cup with titanium inside and stainless steel outside according to claim 4, characterized in that: The specific steps of S1 are: S11, Processing titanium liner: Using pure titanium as the material, the expansion wave machine is processed into the inner liner; S12, Processing Titanium Cup Mouth: Use pure titanium as the material and process it into a titanium cup mouth; S13, Processing of stainless steel cylinder: Use a 0.5mm thick stainless steel plate, process it into the specified size, and form it into a cylindrical shape through rolling + TIG welding. Then use the equipment to complete the specific shape of the cup body. Use a rolling machine to form a step shape at one end of the stainless steel cylinder. The step height difference is 0.5-0.6mm, which will be used to match the titanium cup mouth later. S14, Processing of stainless steel base: Use a stainless steel disc to stretch it into the shape of the shell base, and use a rolling machine to form a stepped shape on one end of the base edge with a step height difference of 0.5-0.6mm. It is then used to cooperate with the stainless steel cylinder. Finally, a cutting machine is used to cut off the excess part to ensure the final size of the base.

6. The method for manufacturing a thermos cup with titanium inside and stainless steel outside according to claim 4, characterized in that: Before assembling in step S4, the weld surfaces of the two metal materials need to be polished and then cleaned with alcohol.

7. The method for manufacturing a thermos cup with titanium inside and stainless steel outside according to claim 4, characterized in that: In step S5, the parameters of electromagnetic pulse welding are: discharge voltage is 20-27KV, pulse frequency is 20-23KHZ, and duration of high-speed pulse is 45-55μs; the welding joint should be located at the center of the coil to ensure the best welding effect.

8. The method for manufacturing a thermos cup with titanium inside and stainless steel outside according to claim 5, characterized in that: In step S6, the welding joint is a butt joint, and the specific welding parameters are: focal length +1, welding power 1300-1350W, laser core diameter 500μm, welding speed 200-300mm / min; the laser beam is controlled to align with the middle position of the weld to maximize the weld quality.

9. The method for manufacturing a thermos cup with titanium inside and stainless steel outside according to claim 5, characterized in that: Joint form: In step S7, the welding joint form is a lap joint, and the specific welding parameters are: focal length +1, welding power 950-1050W, laser core diameter 500μm, welding speed 200-250mm / min; control the position of the laser beam so that it is biased towards the upper titanium plate position, with an offset of 0.2mm.

10. The method for manufacturing a thermos cup with titanium inside and stainless steel outside according to claim 5, characterized in that: In step S8, the vacuuming method is as follows: placing the spherical glass solder into the vacuum hole on the stainless steel base, and placing them in batches into a vacuum furnace, setting the gas pressure to 10 -4 , the temperature reaches 700℃-800℃, and the space between the inner tank and the outer shell is completely vacuumed.

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