Sleeve welding auxiliary device and process
By using low-temperature heat sink fittings to reduce the temperature at the edge of the sleeve, the problem of unevenness in the surface during sleeve welding was solved, achieving efficient welding quality and cost control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-04
- Publication Date
- 2026-03-10
AI Technical Summary
When welding the sleeve to the battery pack side beam, the edge of the sleeve is prone to melting, resulting in an uneven surface. Existing technologies require increased material costs and processing time to solve this problem.
Low-temperature heat sink components are used, including vortex tube coolers, heat-conducting components and heat exchange tubes. Through the non-contact positioning sleeve end face, the low-temperature cold airflow reduces the temperature of the sleeve edge, forming a local low-temperature barrier to prevent the molten pool from expanding.
It effectively reduces the sleeve edge temperature to below 200℃, reduces flash and molten pool expansion, improves welding quality, and reduces material and processing costs.
Smart Images
Figure CN121624599A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of battery pack processing, in particular to a sleeve welding auxiliary device and process. BACKGROUND
[0002] Since the overall structure of the battery box needs to adapt to high-strength vibration and be used for large-mass battery installation, a sleeve is usually welded on the side beam of the battery box to improve the connection strength with the vehicle body. Currently, the MIG (Metal Inert Gas) welding technology is usually used to complete the welding of the sleeve and the side beam. The specific welding requirement is that the height of the sleeve flange reaches about 5 mm, and the edge needs to be flat.
[0003] However, since the molten pool temperature during the welding process is generally between 600 and 900℃, and the arc temperature of the MIG welding process is relatively high (9000℃), the edge position of the welded sleeve is very easy to melt, resulting in uneven sleeve plane and an edge bite defect rate of 90%. In order to ensure the flatness of the sleeve surface, the surface after welding needs to be polished and processed again. Therefore, the height of the sleeve needs to be further increased before welding, which will lead to an increase in material cost and process time cost. SUMMARY
[0004] The present application aims to solve the problem that the edge position of the sleeve is easy to melt when welding the sleeve and the side beam of the battery pack, thereby causing uneven sleeve plane.
[0005] To solve the above problems, as a first aspect, the present application provides a sleeve welding auxiliary device for welding the side beam of a battery box and a sleeve, which comprises a low-temperature heat sink pipe, the low-temperature heat sink pipe comprising a vortex tube cooler, a heat conduction piece and a uniform temperature pipe, the uniform temperature pipe being arranged in the heat conduction piece, the cold flow outlet end of the vortex tube cooler extending into the uniform temperature pipe, the heat conduction piece being in contact with the uniform temperature pipe, and the end face of the heat conduction piece away from the vortex tube cooler being used to face and be spaced apart from the end face of the sleeve.
[0006] Optionally, the heat conduction piece is in a cylindrical shape, the heat conduction piece comprising a central cooling part and an edge cooling part, the central cooling part being used to correspondingly arrange with the middle cavity area of the sleeve, the edge cooling part being used to correspondingly arrange with the circumferential side wall area of the sleeve, and the uniform temperature pipe being embedded between the central cooling part and the edge cooling part.
[0007] Optionally, the vortex tube cooler comprises an inner tube and an outer tube, the inner tube being coaxially arranged in the outer tube, a cold flow channel being formed in the inner tube, and the inner tube and the outer tube jointly defining a hot flow channel, the cold flow channel extending into the uniform temperature pipe, and the hot flow channel being located above the uniform temperature pipe.
[0008] Optionally, the heat-conducting member is made of copper.
[0009] Optionally, the sleeve is positioned by a floating support cylinder.
[0010] As a second aspect, the present application provides a sleeve welding process based on the sleeve welding auxiliary device as described in the first aspect, the sleeve welding process comprising: The sleeve is positioned by a floating support cylinder so that the sleeve is vertically arranged; The low-temperature heat sink pipe is installed opposite to the end face of the positioned sleeve; The sleeve and the side beam are welded by a gas tungsten arc welding process.
[0011] Optionally, when the sleeve is positioned by the floating support cylinder, the height of the end face of the sleeve extending out of the surface of the side beam is controlled to be 5-7 mm.
[0012] Optionally, when the low-temperature heat sink pipe is installed opposite to the end face of the positioned sleeve, the gap between the low-temperature heat sink pipe and the end face of the sleeve is controlled to be 2-3 mm, and the output temperature of the low-temperature heat sink pipe is controlled to be -15 to -10℃.
[0013] Optionally, when the sleeve and the side beam are welded by the gas tungsten arc welding process, the process comprises: If the height of the end face of the sleeve extending out of the surface of the side beam is ≤6 mm, the pulse current of the gas tungsten arc welding process is controlled to be 120-180 A, the welding speed is controlled to be 10-12 mm / s, and the output temperature of the low-temperature heat sink pipe is controlled to be -15 to -13℃. If the height of the end face of the sleeve extending out of the surface of the side beam is >6 mm, the pulse current of the gas tungsten arc welding process is controlled to be 140-200 A, the welding speed is controlled to be 13-15 mm / s, and the output temperature of the low-temperature heat sink pipe is controlled to be -12 to -10℃.
[0014] Optionally, when the sleeve and the side beam are welded by the gas tungsten arc welding process, the process further comprises: controlling the axis direction of the welding torch to form an included angle of 15-20° with the axis direction of the low-temperature heat sink pipe.
[0015] The beneficial effects of the present application compared with the related art include: The application reduces the temperature of the sleeve edge by low-temperature heat sink pipe. Specifically, the vortex pipe cooler extends from top to bottom into the temperature equalizing pipe and the heat conducting pipe, supplies cold air flow at a certain temperature (such as-30℃) into the temperature equalizing pipe, and the cold air flow is first diffused quickly in the temperature equalizing pipe and then transferred to the heat conducting pipe, so that the heat conducting pipe stably maintains a relatively constant temperature (such as-15℃). Finally, the heat conducting pipe is positioned in a non-contact manner with the sleeve end face, the heat absorbed by the heat conducting pipe from the edge of the sleeve end is exchanged by the temperature equalizing pipe, so that the heat generated by the edge of the sleeve end face is quickly conducted to the non-welding area through the heat conducting pipe, forming a local low-temperature barrier. By using the low-temperature heat sink pipe in the application, the heat of the edge of the sleeve end can be quickly extracted by heat conduction, and the temperature of the edge of the sleeve end can be reduced to 200℃ or below, so that the solid-state maintenance time of the edge is prolonged, and the phenomenon of flash and molten pool expansion is avoided. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 FIG. 1 is a structural schematic diagram of a sleeve welding auxiliary device in an exemplary embodiment of the application; Figure 2 FIG. 2 is a sectional view of the sleeve welding auxiliary device in the exemplary embodiment of the application.
[0017] Reference signs: 1, sleeve; 2, side beam; 3, low-temperature heat sink pipe; 31, vortex pipe cooler; 311, cold flow channel; 312, hot flow channel; 313, compressed gas inlet; 314, hot flow outlet; 32, temperature equalizing pipe; 33, heat conducting pipe; 331, central cooling part; 332, edge cooling part; 4, floating support air cylinder; 5, welding gun. DETAILED DESCRIPTION
[0018] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application are described in detail below.
[0019] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing the specific embodiments of the present application, and are not intended to limit the present application; As used herein, the term "includes" and its variants are open-ended, meaning that "includes but is not limited to"; the term "based on" means "based, at least in part, on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". Related definitions are given throughout the description. It is to be noted that the terms "first", "second", and the like, do not denote any particular order or importance, but are used to distinguish one element from another. Furthermore, the terms "first", "second", are used, purely for descriptive purposes, and cannot be construed to connote or imply relative importance or an ordered ranking such as that of a numerical designation. Thus, a feature identified as "first" or "second" can implicitly or explicitly include one or more of the same feature. In the description of the application, the meaning of "a", "an" and "the" is "one or more", unless otherwise specified.
[0020] In the battery pack structure, when the sleeve 1 is welded on the side beam 2 of the battery box to form various shapes, MIG welding is generally used. Since the material of the battery box side beam 2 is mainly aluminum alloy, which is a high-reflective material, the temperature of the molten pool during welding is generally 600-900°C, and the temperature of the MIG arc can reach 9000°C, which causes the end edge position of the sleeve 1 to melt very easily during welding, resulting in unevenness of the sleeve 1 plane and edge welding undercut of the sleeve 1.
[0021] In the related art, the following two methods are generally used to solve the problem of sleeve 1 edge undercut. The first method is to increase the height of the sleeve 1, generally controlling the height before welding to be greater than 10mm, so that after welding, the required height (5-7mm) is achieved through secondary polishing and processing. The disadvantage of this method is that the material cost and processing cost are both high, and the welding structure of the sleeve 1 is numerous on the battery pack, which will take a lot of time to repair parts and debug production process, reducing the production rhythm. The second method is to use a metal shield in the welding area to resist the arc, but the metal shield easily interferes with the welding path, causing the metal shield to heat up during welding, and the temperature of the shield increases, which also affects the temperature of the edge of the sleeve 1, and cannot balance the heat-affected zone control and arc stability. Moreover, when the thickness of the metal shield is not consistent in different areas, the heat-affected size is also different, resulting in unstable welding undercut position, so the arc shielding effect of the metal shield is not ideal.
[0022] To solve the problems in the related art, embodiments of the present application provide a sleeve welding auxiliary device for welding the side beam 2 of the battery box and the sleeve 1. Referring to Figure 1 and Figure 2As shown, the low-temperature heat sink pipe 3 includes a vortex tube cooler 31, a heat conducting member 33, and a uniform temperature pipe 32 embedded in the heat conducting member 33, the cold flow outlet end of the vortex tube cooler 31 extends into the uniform temperature pipe 32, the heat conducting member 33 is in contact with the uniform temperature pipe 32, and the end of the heat conducting member 33 away from the vortex tube cooler is used to be opposite to and spaced apart from the end face of the sleeve 1.
[0023] In the embodiment of the present application, referring to Figure 2 As shown, the vortex tube cooler 31 extends into the uniform temperature pipe 32 and the heat conducting member 33 from top to bottom, and a cold gas flow at a certain temperature (such as -30℃) is supplied into the uniform temperature pipe 32, the cold gas flow first undergoes rapid diffusion in the uniform temperature pipe 32, and then is transferred to the heat conducting member 33, so that the heat conducting member 33 is stably maintained at a relatively constant temperature (such as -15℃). Finally, the heat conducting member 33 is positioned in a non-contact manner with the end face of the sleeve 1, the heat absorbed by the heat conducting member 33 from the edge of the end face of the sleeve 1 is exchanged through the uniform temperature pipe 32, so that the heat generated by the edge of the end face of the sleeve 1 is quickly conducted to the non-welding area through the heat conducting member 33, forming a local low-temperature barrier. By using the low-temperature heat sink pipe 3 in the embodiment of the present application, the heat of the edge of the end face of the sleeve 1 can be quickly extracted through heat conduction, so that the temperature of the edge of the end face of the sleeve 1 is reduced to below 200℃, thereby prolonging the solid-state maintenance time of the edge and avoiding the phenomenon of flash and molten pool expansion.
[0024] It should be noted that the uniform temperature pipe 32 in the embodiment of the present application is a tubular sandwich structure surrounded by a uniform temperature plate and embedded in the heat conducting member 33. The uniform temperature plate is a two-dimensional planar heat conducting device that realizes rapid temperature equalization through evaporation and condensation cycles of working medium in a closed cavity and rapid diffusion of heat through capillary action, and has the functions of heat conduction and heat diffusion. The structure of the uniform temperature plate is composed of a metal shell, an internal capillary structure and a working medium. In the embodiment, the two-dimensional uniform temperature plate is bent into a three-dimensional pipe, and further embedded in the heat conducting member 33, so that the contact area of the uniform temperature plate and the heat conducting member 33 is further increased, thereby enhancing the heat exchange efficiency and avoiding local temperature overheating.
[0025] Specifically, the cold flow outlet end of the vortex tube cooler 31 extends into the uniform temperature pipe 32 from one end of the uniform temperature pipe 32, and then the end of the uniform temperature pipe 32 into which the cold flow outlet end is inserted corresponds to the condensing end of the uniform temperature pipe 32, and the other end of the uniform temperature pipe 32 close to the sleeve 1 is the evaporating end of the uniform temperature pipe 32. The medium in the capillary structure of the uniform temperature pipe 32 absorbs the heat of the heat conducting member 33 at the evaporating end and vaporizes, the generated steam flows to the condensing end and condenses and releases heat, and the condensed liquid returns to the evaporating end, and so on. The end of the heat conducting member 33 away from the vortex tube cooler 31, i.e. the end of the heat conducting member 33 close to the evaporating end of the uniform temperature pipe 32, faces the end face of the sleeve 1, thereby facilitating the rapid heat conduction and heat exchange of the heat conducting member 33 and improving the heat dissipation efficiency.
[0026] In some optional embodiments, referring to Figure 2 As shown, the heat-conducting member 33 is in the shape of a cylinder as a whole, and includes a central cooling portion 331 and an edge cooling portion 332, the central cooling portion 331 is arranged corresponding to the middle cavity region of the sleeve 1, and the edge cooling portion 332 is arranged corresponding to the circumferential side wall region of the sleeve 1, and the uniform temperature tube 32 is embedded between the central cooling portion 331 and the edge cooling portion 332.
[0027] In the embodiment, the heat-conducting member 33 is composed of the central cooling portion 331 and the edge cooling portion 332, which are respectively opposite to the middle cavity region and the edge side region of the sleeve 1, and the uniform temperature tube 32 is clamped between the central cooling portion 331 and the edge cooling portion 332. Thus, the cold airflow generated by the vortex tube cooler 31 can be fully tempered after being conducted to the uniform temperature tube 32, and the uniform temperature tube 32 is in contact with the central cooling portion 331 and the edge cooling portion 332 of the heat-conducting member 33 at the same time, so that each region of the heat-conducting member 33 can be maintained at a constant low temperature, and the sleeve 1 can be uniformly cooled at each edge of the end portion, avoiding the phenomenon of large local temperature difference.
[0028] Further, in some optional embodiments, as shown in Figure 2 The cross-sectional area of the central cooling portion 331 of the heat-conducting member 33 gradually decreases from the end close to the sleeve 1 to the end away from the sleeve 1, and can be in the shape of a circular truncated cone or a prismatic truncated cone. In this way, not only the heat-conducting area corresponding to the end face of the sleeve 1 of the heat-conducting member 33 is large enough, but also the contact area with the uniform temperature tube 32 is increased by the inclined surface, so as to further accelerate the heat exchange rate. It should be noted that when installing the low-temperature heat sink tube 3 in the embodiment of the application, the heat-conducting member 33 and the sleeve 1 can be positioned in a non-contact manner, that is, the end face of the heat-conducting member 33 and the end face of the sleeve 1 have a certain gap, such as about 2 mm, so as to effectively avoid the influence of mechanical stress generated by direct contact on the edge of the sleeve 1.
[0029] In some optional embodiments, the material of the heat-conducting member 33 can be copper, the shell material of the uniform temperature tube 32 can be copper or aluminum alloy, and the working medium can be water.
[0030] In some optional embodiments, the vortex tube cooler 31 includes an inner tube and an outer tube, the inner tube is coaxially arranged in the outer tube, the inner tube is internally provided with a cold flow channel 311, and the inner tube and the outer tube jointly define a hot flow channel 312, the cold flow channel 311 extends into the uniform temperature tube 32, and the hot flow channel 312 is located above the uniform temperature tube 32.
[0031] As shown in Figure 2As shown, the vortex tube cooler 31 has a compressed gas inlet 313 and a hot stream outlet 314 at the end of the inner tube away from the uniform temperature tube 32, the compressed gas inlet 313 is communicated with the cold stream flow channel 311, and the hot stream outlet 314 is communicated with the hot stream flow channel 312. The compressed gas extends to the uniform temperature tube 32 through the cold stream flow channel 311 inside the inner tube, and the vortex tube cooler 31 separates the compressed gas into cold gas flow, which can be introduced into the uniform temperature tube 32 through the cold stream flow channel 311 and reduce the temperature of the heat conduction piece 33 after uniform temperature. The cold gas flow becomes hot gas flow after absorbing heat, and the hot gas flow moves upward and is discharged out of the vortex tube cooler 31 along the hot stream flow channel 312. In an exemplary embodiment, the temperature of the cold gas flow output by the vortex tube cooler 31 can be-30℃, and the temperature of the end face of the heat conduction piece 33 opposite to the sleeve 1 can be maintained at about-15℃ after uniform temperature, which is the output temperature of the low-temperature heat sink pipe 3.
[0032] In some alternative embodiments, referring to Figure 1 and Figure 2 As shown, the sleeve welding auxiliary device further comprises a floating support air cylinder 4 for floating supporting the sleeve 1. Specifically, the output end of the floating support air cylinder 4 is connected with the end of the sleeve 1, and the end thereof has a positioning pin for limiting the movement distance thereof. The floating support air cylinder 4 is used to control the height of the sleeve 1 extending out of the side beam 2 by pushing up or pressing down, and since the height of the sleeve 1 extending out of the side beam 2 needs to be controlled before welding, the floating support air cylinder 4 not only stably supports the sleeve 1, but also helps to keep the height of the sleeve 1 extending out of the side beam 2 stable, so as to timely adjust or compensate, thereby further ensuring the welding quality of the sleeve 1.
[0033] Another embodiment of the present application also provides a sleeve welding process based on the sleeve welding auxiliary device as described above, and the sleeve welding process comprises the following steps: Step (I): positioning the sleeve 1 by using the floating support air cylinder 4, so that the sleeve 1 is vertically arranged. Specifically, the sleeve 1 to be welded can be installed to the corresponding hole position of the battery pack side beam 2 by the floating support air cylinder 4, and then the height of the end face of the sleeve 1 extending out of the surface of the side beam 2 is controlled to be 5-7mm, as shown in Figure 2 wherein h represents the height of the sleeve 1 extending out of the side beam 2.
[0034] Step (II): Install the low-temperature heat sink fitting 3 facing the end face of the positioned sleeve 1. For example, in welding applications where cooling of the upper end face of the sleeve 1 is required, the low-temperature heat sink fitting 3 should be installed facing the upper end face of the positioned sleeve 1 with a gap between them. Specifically, the gap between the low-temperature heat sink fitting 3 and the end face of the sleeve 1 can be controlled to be 2 to 3 mm, and the output temperature of the low-temperature heat sink fitting 3 can be controlled to be -15 to -10℃. It should be noted that the output temperature of the low-temperature heat sink fitting 3 is the temperature of the end face of the heat-conducting component 33 facing the sleeve 1.
[0035] Step (3): Weld sleeve 1 to side beam 2 using gas metal arc welding (GMAW). Specifically, as follows... Figure 1 As shown, the axial direction of the welding torch 5 can be controlled to form an angle of 15 to 20° with the axial direction of the low-temperature heat sink tube 3, thereby causing the arc center to shift to the cooling side to avoid the low-temperature zone. The welding torch 5 can be controlled by a robot to swing. In an exemplary embodiment, the robot swing frequency can be 3.5 Hz, the amplitude can be 1.5 / 1.0, and the swing pattern can be crescent-shaped.
[0036] Furthermore, a dual-pulse welding method can be employed to ensure sufficient heat input and weld filler volume. Simultaneously, welding process parameters can be determined based on the height of the sleeve 1's end face extending beyond the surface of the side beam 2, thereby controlling the arc height and welding heat input, and adjusting the cooling intensity accordingly in real time. The specific control process can be as follows: If the height of the end face of sleeve 1 extending beyond the surface of side beam 2 is ≤6mm, then the pulse current range of the gas metal arc welding process is 120 to 180A, the welding speed is 10 to 12mm / s, and the output temperature of the low-temperature heat sink fitting 3 is controlled to be -15 to -13℃.
[0037] If the height of the end face of sleeve 1 extending beyond the surface of side beam 2 is greater than 6mm, then the pulse current range of the gas metal arc welding process is 140 to 200A, the welding speed is 13 to 15mm / s, and the output temperature of the low-temperature heat sink fitting 3 is controlled to be -12 to -10℃.
[0038] The above control method allows for real-time adjustment of welding process parameters and cooling temperature, which helps to ensure sufficient heat input during the welding process while limiting the heat to a certain depth range to guarantee the edge quality of sleeve 1 and reduce cooling costs.
[0039] By comprehensively employing the low-temperature heat sink pipe 3 and welding process in the embodiments of the present invention, the edge temperature of the sleeve 1 during the welding process can be controlled within 200°C, the width of the heat-affected zone at the weld edge can be reduced by 40% to 60%, the arc root width on the low-temperature side can be reduced by 8%, the minimum pre-welding height of the sleeve 1 can reach 5mm, and the edge flatness deviation of the sleeve 1 can be within 0.1mm.
[0040] Although the present application has been disclosed with reference to the above embodiments, the application is not limited to the above embodiments. It will be apparent to those skilled in the art that various changes and modifications can be made thereto without departing from the spirit and scope of the application, and it is intended to include all such changes and modifications as fall within the scope of the application.
Claims
1. A sleeve welding assist device characterized by, The application relates to a sleeve welding auxiliary device for welding a side beam (2) of a battery box with a sleeve (1), wherein the sleeve welding auxiliary device comprises a low-temperature heat sink pipe (3), the low-temperature heat sink pipe (3) comprises an eddy current pipe cooler (31), a heat conduction pipe (33) and a uniform temperature pipe (32), the uniform temperature pipe (32) is arranged in the heat conduction pipe (33), the cold flow outlet end of the eddy current pipe cooler (31) extends into the uniform temperature pipe (32), the heat conduction pipe (33) is in contact with the uniform temperature pipe (32), and the end face of the heat conduction pipe (33) away from the eddy current pipe cooler (31) is used for being opposite to and spaced from the end face of the sleeve (1).
2. The sleeve welding assist of claim 1, wherein, The heat conduction pipe (33) is in a cylindrical shape, the heat conduction pipe (33) comprises a central cooling part (331) and an edge cooling part (332), the central cooling part (331) is arranged in correspondence with the middle cavity area of the sleeve (1), the edge cooling part (332) is arranged in correspondence with the circumferential side wall area of the sleeve (1), and the uniform temperature pipe (32) is embedded between the central cooling part (331) and the edge cooling part (332).
3. The sleeve welding assist of claim 1, wherein, The eddy current pipe cooler (31) comprises an inner pipe and an outer pipe, the inner pipe is coaxially arranged in the outer pipe, a cold flow channel (311) is formed in the inner pipe, the inner pipe and the outer pipe jointly define a hot flow channel (312), the cold flow channel (311) extends into the uniform temperature pipe (32), and the hot flow channel (312) is located above the uniform temperature pipe (32).
4. The sleeve welding assist of claim 1, wherein, The material of the heat conduction pipe (33) is copper.
5. The sleeve welding assist of claim 1, wherein, The sleeve welding auxiliary device further comprises a floating support air cylinder (4) for floatingly supporting the sleeve (1).
6. A sleeve welding process characterized by, The sleeve welding process is based on the sleeve welding auxiliary device as claimed in any one of claims 1 to 5, and the sleeve welding process comprises the following steps. The floating support air cylinder (4) is used for positioning the sleeve (1) so that the sleeve (1) is vertically arranged; The low-temperature heat sink pipe (3) is installed opposite to the end face of the positioned sleeve (1); The sleeve (1) is welded with the side beam (2) by adopting a gas tungsten arc welding process.
7. The sleeve welding process of claim 6, wherein, When the floating support air cylinder (4) is used for positioning the sleeve (1), the height of the end face of the sleeve (1) extending out of the surface of the side beam (2) is controlled to be 5 to 7 mm.
8. The sleeve welding process of claim 7, wherein, When the low-temperature heat sink pipe (3) is installed opposite to the end face of the positioned sleeve (1), the gap between the low-temperature heat sink pipe (3) and the end face of the sleeve (1) is controlled to be 2 to 3 mm, and the output temperature of the low-temperature heat sink pipe (3) is controlled to be -15 to -10 DEG C.
9. The sleeve welding process of claim 8, wherein, When the sleeve (1) is welded with the side beam (2) by adopting the gas tungsten arc welding process, the following steps are included: If the height of the end face of the sleeve (1) extending out of the surface of the side beam (2) is less than or equal to 6 mm, the pulse current of the gas tungsten arc welding process is controlled to be 120 to 180 A, the welding speed is controlled to be 10 to 12 mm / s, and the output temperature of the low-temperature heat sink pipe (3) is controlled to be -15 to -13 DEG C. If the height of the end face of the sleeve (1) protruding from the surface of the side beam (2) is greater than 6 mm, the pulse current range of the gas shielded welding process is 140-200 A, the welding speed is 13-15 mm / s, and the output temperature of the low-temperature heat sink pipe (3) is controlled to be -12 to -10℃.
10. The sleeve welding process of claim 6, wherein, When the sleeve (1) and the side beam (2) are welded by the gas shielded welding process, the axis direction of the welding gun (5) is controlled to have an included angle of 15-20° with the axis direction of the low-temperature heat sink pipe (3).