Manufacturing process for stably welded kettle body with titanium inside and steel outside

Abstract

The invention relates to the field of production and manufacturing of cups and kettles, in particular to a manufacturing process of a titanium-inside steel-outside stable welding kettle body, which comprises the following steps of: taking and cleaning a titanium inner container and a stainless steel semi-finished product interlayer, then pickling the stainless steel semi-finished product interlayer, and cleaning and drying the stainless steel semi-finished product interlayer after pickling; then the liner and the semi-finished product interlayer are connected in a sleeving mode to enable the opening edges of the liner and the semi-finished product interlayer to be aligned, composite laser is used for welding, and electric arcs and laser beams are used for heating welding when the composite laser works; then sequentially completing the steps of interlayer bottom welding, semi-finished product shell welding, shell bottom sheet welding and vacuumizing; on the premise that the titanium inner container is reserved, the problem that welding of the titanium inner container and the stainless steel material is not stable and tight enough is solved.

Description

Technical Field

[0001] The invention relates to the field of cup and pot production and manufacturing, and in particular to a manufacturing process for a pot body stably welded with titanium inside and steel outside. Background Art

[0002] The body of an existing thermos pot is usually supported by a double layer of stainless steel. A vacuum is drawn between the double layers of stainless steel to achieve the insulation effect. The efficiency of heat transfer in the vacuum layer is low to achieve the effect of heat preservation of the liquid in the pot body. However, the existing inner liner is generally made of stainless steel. When acidic beverages are poured into the inner liner, heavy metals will precipitate. In addition, the beverage in such an inner liner is easy to deteriorate and change the taste, resulting in a poor user experience.

[0003] Therefore, thermos bottles supported by titanium materials have appeared on the market, especially those with titanium inner liner and stainless steel outer shell, which can solve the problem of heavy metal precipitation of traditional stainless steel inner liner when holding acidic beverages, as well as beverage deterioration and poor taste, and also take into account economy; however, due to the different melting points of titanium and stainless steel, welding of titanium and stainless steel usually requires special solders, which usually contain heavy metals such as silver and copper. When the welding position is located at the mouth of the inner liner, it has been tested that the heavy metals in the solder still migrate into the inner liner after long-term use; in order to improve this shortcoming, a laser welding method of the titanium inner liner and the stainless steel outer shell has been developed. This welding method forms a weld in the welding area by irradiation with a pulsed laser beam, but this welding method is prone to pores and cracks, and the weld quality is not stable enough, resulting in the problem that the titanium inner liner connection is not stable and tight enough.

[0004] Therefore, how to manufacture a thermos pot body with stable welding of titanium and stainless steel and good airtightness while using a titanium inner liner to overcome the problem of heavy metal precipitation and beverage deterioration when containing acidic beverages is a technical problem that industry insiders need to solve. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a manufacturing process for a kettle body with stable inner titanium and outer steel welding, which solves the problem of the unstable and tight welding between the titanium inner liner and the stainless steel material while retaining the titanium inner liner.

[0006] The technical solution adopted by the present invention is: a manufacturing process of a kettle body with inner titanium and outer steel stably welded, comprising the following steps:

[0007] S1: Take an inner liner, the material of which is titanium or titanium alloy, and take a semi-finished interlayer; the semi-finished interlayer is cylindrical in shape and is made of stainless steel;

[0008] S2: Clean the inner tank and semi-finished product compartment to remove surface oil and dust;

[0009] S3: immersing the semi-finished interlayer in a pickling solution for pickling treatment, wherein the pickling solution contains 20-40% nitric acid by volume, the temperature of the pickling solution is 20-50° C., and the semi-finished interlayer is immersed in the pickling solution for at least 10 minutes;

[0010] S4: cleaning and drying the semi-finished interlayer after pickling;

[0011] S5: The opening of the inner liner and the opening of the semi-finished interlayer are mutually sleeved to form an interference fit, and the edge of the opening of the inner liner is aligned with the edge of the opening of the semi-finished interlayer; in a protective gas environment, the opening edge of the inner liner and the opening edge of the semi-finished interlayer are welded by using a composite laser. During the composite laser welding process, the laser beam and the arc act on the welding area at the same time;

[0012] S6: Take a partition bottom sheet and weld the partition bottom sheet to the bottom of the semi-finished partition to form a middle partition;

[0013] S7: Take a semi-finished shell, which is made of stainless steel and is cylindrical in shape, and sleeve the semi-finished shell on the outside of the middle partition layer, with the mouth of the semi-finished shell lower than the mouth of the middle partition layer, and then weld the mouth of the semi-finished shell to the middle partition layer;

[0014] S8: Take a shell bottom sheet with vacuum holes, the shell bottom sheet is made of stainless steel, weld the shell bottom sheet to the bottom of the semi-finished shell to form a shell body, and then evacuate the shell.

[0015] Through the above technical scheme, the titanium liner and the semi-finished stainless steel interlayer are cleaned to remove oil and dust on the surface of both. The semi-finished stainless steel interlayer is also pickled to remove the oxide scale and rust on the surface of the semi-finished stainless steel interlayer and reduce the stress of the semi-finished stainless steel interlayer. After such treatment, the inner liner and the semi-finished interlayer can provide a clean, smooth and highly active surface at the mutual welding point, making the subsequent welding more firm and tight; in the composite laser, the laser beam and the arc act at the same time. Under the action of the laser, the arc can penetrate into the depth of the joint to increase the melting depth, and under the action of the arc, the laser absorption rate of the metal in the welding area will also be increased, which improves the melting degree of titanium and stainless steel, and effectively slows down the solidification time of the molten pool metal, increases the phase change time of the molten pool, fully removes the gas in the molten pool, and reduces defects such as pores and cracks, making the welding of the inner liner and the semi-finished interlayer more stable and more airtight.

[0016] Furthermore, when hybrid laser welding is performed in step S5, the power of the laser beam is 4-10 kW, the power of the arc is 3-8 kW, and the welding speed of the hybrid laser is 2-5 m / min.

[0017] Through the above technical solution, the power output of the laser beam and the power output of the arc are controlled within a reasonable range, so that the laser beam and the arc work together. According to the welding requirements, the user can adjust the output power of the laser beam and the arc within the above range to obtain an ideal ratio of penetration depth to weld width.

[0018] Furthermore, when hybrid laser welding is performed in step S5, the arc current is 150-300A, and the arc voltage is 20-30V.

[0019] Through the above technical scheme, the current and voltage values ​​of arc welding are set within a reasonable range, which not only ensures sufficient melting depth and width during welding, but also avoids burn-through or collapsed welds caused by excessive current, and avoids the appearance of pores and oxidation inclusions in the welds caused by excessive voltage, and avoids metal splashing.

[0020] Furthermore, when composite laser welding is used in step S5, the spot diameter of the laser beam is 0.6-1 mm, the wavelength of the laser beam is 1030-1080 nm, the wavelength pulse frequency of the laser beam is 100-500 Hz, and the pulse width is 1-5 ms.

[0021] Through the above technical scheme, the various values ​​of the laser beam are adapted to the requirements of the welding of the titanium liner and the semi-finished interlayer, avoiding the laser beam wavelength being too long, which leads to a decrease in the laser absorption rate, resulting in low energy utilization and insufficient melting depth, and avoiding the laser beam wavelength being too short, which leads to ablation of the welding area; avoiding the laser beam pulse frequency being too high, which leads to a decrease in single pulse energy and the occurrence of cold welding or unmelted defects; avoiding the laser beam pulse frequency being too low, which leads to discontinuous welds.

[0022] Furthermore, the protective gas in step S5 is a mixed gas of argon and helium.

[0023] Through the above technical solution, oxygen can be isolated during the composite laser welding process, oxidation reaction can be prevented, and the laser equipment can be protected.

[0024] Furthermore, the inner container in step S1 has been subjected to a crystallization process, and the steps of the crystallization are as follows:

[0025] Surface pretreatment step: clean and dry the inner tank to ensure its surface is smooth;

[0026] Environmental condition preparation step: placing the inner container in the furnace and evacuating the vacuum until the inner container is in an environment of 0.01 Pa or less;

[0027] Preheating step: heating to 200-450°C and keeping warm for 20-40 minutes;

[0028] A heating step, heating to 450°C and continuously increasing the temperature at a heating rate of 5-10°C / min until the temperature reaches 850°C;

[0029] In the crystallization step, the temperature is maintained at 850-1100°C for 60-120 minutes;

[0030] In the cooling step, the temperature is first lowered at a rate of 2-5°C, and then naturally cooled to room temperature.

[0031] Through the above technical solution, the strength, toughness and corrosion resistance of the titanium inner liner are improved after crystallization treatment. During the welding process, the grain boundaries of the titanium material are more uniform, which makes the fluidity of the molten pool more stable during welding, reduces defects such as pores and cracks, and further improves the welding quality.

[0032] Furthermore, in step S3, the time for which the semi-finished interlayer is immersed in the pickling solution is controlled to be 10-45 minutes.

[0033] Through the above technical solution, the pickling time of the semi-finished interlayer is controlled within a reasonable range, thereby avoiding excessive corrosion of the semi-finished interlayer due to pickling for too long and avoiding poor fusion during welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0035] Figure 1 It is one of the cross-sectional views during the process of the present invention;

[0036] Figure 2 This is the second cross-sectional view during the process of the present invention;

[0037] Figure 3 It is a schematic diagram of a kettle body of the present invention;

[0038] Figure 4 for Figure 3 A local enlarged view of point A;

[0039] Figure 5 It is an overall schematic diagram of the kettle body of the present invention;

[0040] The invention number information is as follows:

[0041] 1. Inner liner; 2. Middle interlayer; 3. Outer shell; 21. Semi-finished interlayer; 22. Interlayer bottom film; 31. Semi-finished outer shell; 32. Outer shell bottom film;

[0042] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0043] 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.

[0044] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0045] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0046] Before the manufacturing process of the inner titanium and outer steel stable welded kettle body is implemented, a titanium inner liner 1 is taken and the inner liner 1 is crystallized. The steps of crystallization are as follows:

[0047] Surface pretreatment step: cleaning and drying the inner tank 1 to ensure that its surface is smooth;

[0048] Environmental condition preparation step, placing the inner container 1 in the furnace and evacuating the inner container 1 until the inner container 1 is in an environment of 0.01 Pa or less;

[0049] Preheating step: heating to 200-450°C and keeping warm for 20-40 minutes;

[0050] A heating step, heating to 450°C and continuously increasing the temperature at a heating rate of 5-10°C / min until the temperature reaches 850°C;

[0051] In the crystallization step, the temperature is maintained at 850-1100°C for 60-120 minutes;

[0052] Cooling step: First, cool down at a rate of 2 - 5 °C, and then naturally cool to room temperature.

[0053] After the crystallization treatment, the titanium inner liner 1 has improved strength, toughness, and corrosion resistance. During the welding process, due to the more uniform grain boundaries of the titanium material, the fluidity of the molten pool during welding is more stable, reducing defects such as pores and cracks, and further improving the welding quality.

[0054] A manufacturing process for a stable welded kettle body with a titanium inner and a steel outer includes the following steps:

[0055] S1: Take the above-mentioned inner liner 1, the material of the inner liner 1 is titanium or titanium alloy, and take a semi-finished product partition layer 21; the semi-finished product partition layer 21 is overall cylindrical, and the material of the semi-finished product partition layer 21 is stainless steel;

[0056] S2: Clean the inner liner 1 and the semi-finished product partition layer 21 to remove surface oil stains and dust;

[0057] S3: Immerse the semi-finished product partition layer 21 in an acid pickling solution for acid pickling treatment. The acid pickling solution contains 20 - 40% nitric acid by volume percentage, the temperature of the acid pickling solution is 20 - 50 °C, and the immersion time of the semi-finished product partition layer 21 in the acid pickling solution is at least 10 min;

[0058] The immersion time of the semi-finished product partition layer 21 in the acid pickling solution is preferably controlled within 10 - 45 min. Controlling the pickling time of the semi-finished product partition layer 21 within a reasonable range can avoid the phenomenon of over-corrosion caused by over-pickling of the semi-finished product partition layer 21 and avoid the situation of poor fusion during welding.

[0059] S4: Clean and dry the acid pickling-treated semi-finished product partition layer 21;

[0060] S5: Socket the opening of the inner liner 1 and the opening of the semi-finished product partition layer 21 to form an interference fit, and align the edge of the opening of the inner liner 1 with the edge of the opening of the semi-finished product partition layer 21; in an environment of protective gas, use a composite laser to weld the opening edge of the inner liner 1 and the opening edge of the semi-finished product partition layer 21. During the composite laser welding process, the laser beam and the arc act on the welding area simultaneously; as Figure 1 shown;

[0061] The protective gas in step S5 is a mixed gas of argon and helium. This makes it possible to isolate oxygen during the composite laser welding process, prevent oxidation reactions from occurring, and protect the laser equipment.

[0062] S6: Take a partition bottom plate 22 and weld the partition bottom plate 22 to the bottom of the semi-finished product partition layer 21 to form an intermediate partition layer 2, as Figure 2 shown;

[0063] S7: Take a semi-finished shell 31, which is made of stainless steel and is cylindrical in shape, and sleeve the semi-finished shell 31 on the outside of the middle partition 2, with the mouth of the semi-finished shell 31 lower than the mouth of the middle partition 2, and then weld the mouth of the semi-finished shell 31 to the middle partition 2;

[0064] S8: Take a shell bottom sheet 32 ​​with a vacuum hole, the shell bottom sheet 32 ​​is made of stainless steel, weld the shell bottom sheet 32 ​​to the bottom of the semi-finished shell 31 to form the shell body 3, and then evacuate the shell body 3. Figure 3-Figure 5 shown.

[0065] The titanium inner liner 1 and the stainless steel semi-finished interlayer 21 are both cleaned to remove oil and dust on the surface of both. The stainless steel semi-finished interlayer 21 is also pickled to remove the oxide scale and rust on the surface of the stainless steel semi-finished interlayer 21 and reduce the stress of the semi-finished interlayer 21. After such treatment, the inner liner 1 and the semi-finished interlayer 21 can provide a clean, smooth and highly active surface at the mutual welding point, making the subsequent welding more firm and tight; in the composite laser, the laser beam and the arc act at the same time. Under the action of the laser, the arc can penetrate deep into the joint to increase the melting depth, and under the action of the arc, the laser absorption rate of the metal in the welding area is also increased, which improves the melting degree of titanium and stainless steel, and effectively slows down the solidification time of the molten pool metal, increases the molten pool phase change time, fully removes the gas in the molten pool, and reduces defects such as pores and cracks, making the welding of the inner liner 1 and the semi-finished interlayer 21 more stable and more airtight.

[0066] Preferably, the material of the inner liner 1 is pure titanium.

[0067] When hybrid laser welding is used in step S5, the power of the laser beam is 4-10KW, the power of the arc is 3-8KW, and the welding speed of the hybrid laser is 2-5m / min.

[0068] The output power of the laser beam and the output power of the arc are controlled within a reasonable range so that the laser beam and the arc can work together. According to the welding requirements, the user can adjust the output power of the laser beam and the arc within the above range to obtain the ideal ratio of penetration depth to weld width.

[0069] When hybrid laser welding is performed in step S5, the arc current is 150-300A and the arc voltage is 20-30V.

[0070] Setting the arc welding current and voltage values ​​within a reasonable range not only ensures sufficient penetration depth and width during welding, but also avoids burn-through or collapsed welds caused by excessive current, as well as porosity and oxidation inclusions in the weld caused by excessive voltage, and avoids metal splashing.

[0071] When composite laser welding is performed in step S5, the spot diameter of the laser beam is 0.6-1 mm, the wavelength of the laser beam is 1030-1080 nm, the wavelength pulse frequency of the laser beam is 100-500 Hz, and the pulse width is 1-5 ms.

[0072] The various values ​​of the laser beam are adapted to the requirements of welding the titanium liner 1 and the semi-finished interlayer 21, to avoid the laser beam wavelength being too long, which leads to a decrease in the laser absorption rate, resulting in low energy utilization and insufficient melting depth; to avoid the laser beam wavelength being too short, which leads to ablation of the welding area; to avoid the laser beam pulse frequency being too high, which leads to a decrease in single pulse energy and the occurrence of cold welding or unmelted defects; to avoid the laser beam pulse frequency being too low, which leads to discontinuous welds.

[0073] Embodiment: A kettle body made by the above method, wherein the pickling solution contains 30% nitric acid by volume, the temperature of the pickling solution is 40°C, and the semi-finished interlayer 21 is immersed in the pickling solution for at least 15 minutes; the arc current in the composite laser is 240V, the voltage is 25V, the spot diameter in the composite laser is 0.7mm, the wavelength is 1050nm, the pulse frequency is 400, and the pulse width is 2ms;

[0074] Comparative example: In the above method of the present invention, steps S3 and S4 are removed, and the composite laser in step S5 is replaced by an ordinary single laser treatment, wherein the spot diameter is 0.7 mm, the wavelength is 1050 nm, the pulse frequency is 400, and the pulse width is 2 ms.

[0075] The present invention allocates ten kettle bodies to each of the embodiment and the comparative example, and the kettle bottom is dropped from a height of 1200mm to a cement floor covered with a hemp carpet at a vertical downward angle. Then, ten kettle bodies are allocated to each of the embodiment and the comparative example, and the kettle body is dropped from a height of 1200mm to a cement floor covered with a hemp carpet at a horizontal horizontal downward angle. Then, it is observed whether cracks are formed at the welding part of the mouth of the inner tank 1 and the mouth of the middle partition 2. If cracks are formed, the proportion of the cracks in the circumferential direction is calculated, and the final value is the average value of the realized data of each group. The results are as follows:

[0076]

[0077] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A manufacturing process for a pot body with titanium inside and steel outside that is stably welded, characterized in that: The steps include: S1: Take an inner liner (1), the material of the inner liner (1) is titanium or titanium alloy, and take a semi-finished interlayer (21); the semi-finished interlayer (21) is cylindrical in shape as a whole, and the material of the semi-finished interlayer (21) is stainless steel; S2: Clean the inner container (1) and the semi-finished interlayer (21) to remove surface oil and dust; S3: immersing the semi-finished interlayer (21) in a pickling solution for pickling treatment, wherein the pickling solution contains 20-40% nitric acid by volume, the temperature of the pickling solution is 20-50° C., and the semi-finished interlayer (21) is immersed in the pickling solution for at least 10 minutes; S4: cleaning and drying the pickled semi-finished interlayer (21); S5: the opening of the inner liner (1) and the opening of the semi-finished interlayer (21) are mutually sleeved to form an interference fit, and the edge of the opening of the inner liner (1) is aligned with the edge of the opening of the semi-finished interlayer (21); in a protective gas environment, the edge of the opening of the inner liner (1) and the edge of the opening of the semi-finished interlayer (21) are welded using a composite laser, and during the composite laser welding process, the laser beam and the arc act on the welding area simultaneously; S6: taking a partition bottom sheet (22), and welding the partition bottom sheet (22) to the bottom of the semi-finished partition (21) to form a middle partition (2); S7: Take a semi-finished shell (31), which is made of stainless steel and is cylindrical in shape, and sleeve the semi-finished shell (31) on the outside of the middle partition (2), with the mouth of the semi-finished shell (31) lower than the mouth of the middle partition (2), and then weld the mouth of the semi-finished shell (31) to the middle partition (2); S8: Take a shell bottom sheet (32) with vacuum holes, the shell bottom sheet (32) is made of stainless steel, weld the shell bottom sheet (32) to the bottom of the semi-finished shell (31) to form the shell body (3), and then evacuate.

2. The manufacturing process of a stable welded kettle body with titanium inside and steel outside according to claim 1 is characterized by: When hybrid laser welding is used in step S5, the power of the laser beam is 4-10KW, the power of the arc is 3-8KW, and the welding speed of the hybrid laser is 2-5m / min.

3. The manufacturing process of a stable welded kettle body with titanium inside and steel outside according to claim 2 is characterized by: When hybrid laser welding is performed in step S5, the arc current is 150-300A and the arc voltage is 20-30V.

4. The manufacturing process of a stable welded kettle body with titanium inside and steel outside according to claim 2 is characterized by: When composite laser welding is performed in step S5, the spot diameter of the laser beam is 0.6-1 mm, the wavelength of the laser beam is 1030-1080 nm, the wavelength pulse frequency of the laser beam is 100-500 Hz, and the pulse width is 1-5 ms.

5. The manufacturing process of a stable welded kettle body with titanium inside and steel outside according to claim 1 is characterized by: The protective gas in step S5 is a mixed gas of argon and helium.

6. The manufacturing process of a kettle body with titanium inside and steel outside stably welded according to claim 1, 2, 3, 4 or 5, characterized in that: The inner container (1) in step S1 has been subjected to a crystallization process, and the steps of the crystallization are as follows: A surface pretreatment step of washing and drying the inner container (1) to ensure that its surface is smooth; Environmental condition preparation step, placing the inner container (1) in a furnace and evacuating the inner container (1) until the inner container (1) is in an environment of 0.01 Pa or less; Preheating step: heating to 200-450°C and keeping warm for 20-40 minutes; A heating step, heating to 450°C and continuously increasing the temperature at a heating rate of 5-10°C / min until the temperature reaches 850°C; In the crystallization step, the temperature is maintained at 850-1100°C for 60-120 minutes; In the cooling step, the temperature is first lowered at a rate of 2-5°C, and then naturally cooled to room temperature.

7. The manufacturing process of a stable welded kettle body with titanium inside and steel outside according to claim 6, characterized in that: In step S3, the time for the semi-finished interlayer (21) to be immersed in the pickling solution is controlled to be 10-45 minutes.

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