A positioning fixture for metal welding and a method of using the same

Abstract

The application relates to the technical field of metal processing, in particular to a positioning clamp for metal welding and a using method thereof, which comprises a supporting assembly, a clamping assembly and a cooling assembly; the supporting assembly is used for placing a flange and pre-fixing a pipeline; the clamping assembly drives a pushing rod through a pushing cylinder driven by a pushing ring, so that multiple rotating clamping plates are cooperatively actuated to clamp the flange; the cooling assembly comprises a gas cooling piece arranged on the rotating clamping plate and a liquid cooling piece arranged on a pipeline positioner, which are used for synchronously cooling the outside of a welding position and the inside of the pipeline respectively. The application can realize accurate positioning and automatic clamping of a workpiece, accelerate heat dissipation through an inside-outside bidirectional cooling mechanism, effectively prevent thermal deformation, and improve welding precision and work efficiency.

Description

Technical Field

[0001] This invention relates to the field of metal processing technology, and in particular to a positioning fixture for metal welding and its method of use. Background Technology

[0002] Metal welding is a critical process in machinery manufacturing, petrochemicals, and pipeline engineering construction, with pipe-flange connections being particularly common. In current industrial production, to ensure the strength and sealing of welded joints, specialized positioning fixtures are typically used to assist in clamping and securing the workpieces. Conventional welding positioning techniques rely primarily on mechanical structures to achieve spatial constraints on the workpieces. The basic process involves placing the flange on a support platform, performing initial alignment of the pipe using manual or pneumatic devices, and then tightening the clamping components via a screw, linkage mechanism, or hydraulic cylinder to eliminate gaps between the workpieces and maintain relative positional stability. After welding, some advanced tooling systems incorporate auxiliary cooling measures, such as natural air cooling or simple spray systems around the workpieces, to accelerate the temperature drop in the weld area, thereby shortening the production cycle and preparing for the next process.

[0003] However, in long-term engineering practice and large-scale industrial applications, the field of metal welding still faces a series of technical bottlenecks that urgently need to be overcome. Especially in the precision docking of pipes and flanges, maintaining extremely high coaxiality and positional stability under large-size or complex working conditions, while simultaneously ensuring efficient thermal management after welding, is a common challenge. Existing technologies often struggle to ensure precise multi-degree-of-freedom adjustment while rapidly clamping, and lack a mechanism to simultaneously coordinate internal and external heat dissipation paths when facing the thermal stress generated by high-temperature welding. This results in limited cooling efficiency, easily leading to workpiece thermal deformation or residual stress concentration, which in turn affects the geometric accuracy and service reliability of the overall welded structure, limiting further improvements in production cycle time. Summary of the Invention

[0004] The purpose of this invention is to provide a positioning fixture for metal welding and its usage method, which can solve the technical problems that existing technologies often cannot ensure precise adjustment of multiple degrees of freedom while clamping quickly, and lack a mechanism to coordinate the internal and external heat dissipation paths in the face of thermal stress generated by high-temperature welding, resulting in limited cooling efficiency, easy to cause workpiece thermal deformation or residual stress concentration, and thus affecting the geometric accuracy and service reliability of the overall welded structure.

[0005] The first aspect of this application provides a positioning fixture for metal welding, including a support assembly, a clamping assembly, and a cooling assembly. The support assembly includes a base, a support platform, and a pipe positioner. The support platform is fixedly connected to the base and located on top of the base for placing a flange to be welded. The pipe positioner is positioned above the support platform for pre-fixing the pipe to be welded. The clamping assembly includes multiple rotating clamps, multiple push rods, a push ring, and a push cylinder. The multiple rotating clamps are rotatably mounted on the support platform, and the push ring is slidably mounted below the support platform. One end of each push rod is rotatably connected to one of the multiple rotating clamps, and the other end of each push rod is rotatably connected to the push ring. The output end of the push cylinder is connected to the push ring. The cooling assembly includes a gas cooling element and a liquid cooling element. The gas cooling element is mounted on the rotating clamps for gas cooling of the welding position on the flange. The liquid cooling element is mounted on the pipe positioner for liquid cooling of the inside of the pipe.

[0006] The pipeline positioner includes a support cylinder, a support plate, and a positioning component. The support cylinder is located above the support platform, the support plate is connected to the output end of the support cylinder, and the positioning component is located on the support plate for fixing the pipeline.

[0007] The positioning component includes multiple positioning plates, multiple rotating rods, a sliding cone disc, and a second cylinder. The multiple rotating rods are rotatably mounted on the support plate, and the positioning plates are rotatably mounted on the rotating rods. The sliding cone disc is slidably mounted on the support plate. The output end of the second cylinder is connected to the sliding cone disc. When the sliding cone disc moves upward, it pushes the multiple rotating rods to rotate outward to clamp the positioning plate against the pipe.

[0008] The rotating clamp includes an adjusting block, a clamp body, and a locking block. The adjusting block is slidably mounted on the support platform, the clamp body is rotatably mounted on the adjusting block, and the locking block is used to lock the position of the adjusting block.

[0009] The rotating clamp also includes a friction pad, which is fixed to the clamp body.

[0010] The gas cooling component includes a connecting rod, a gas nozzle, and an air pump. The connecting rod is mounted on the clamping plate body, the gas nozzle is mounted on the connecting rod, and the air pump is connected to the gas nozzle.

[0011] The liquid cooling component includes a liquid nozzle, a return channel, a liquid pump, a storage tank, and a cooler. The liquid nozzle is mounted on a rotating rod. The liquid pump is connected to both the liquid nozzle and the storage tank. The return channel is located below the support platform and is connected to the storage tank. The cooler is mounted on the storage tank and is used to cool the storage tank.

[0012] The liquid storage tank includes a tank body and multiple heat sinks, with the heat sinks distributed on the tank body.

[0013] The housing also includes a filter screen and a support plate. The support plate is slidably connected to the housing and is located at the entrance of the housing. The filter screen is installed on the support plate.

[0014] The second aspect of this application provides a method of using a positioning fixture for metal welding, employing any one of the aforementioned positioning fixtures for metal welding.

[0015] This application provides a positioning fixture for metal welding. This solution integrates a support assembly, a clamping assembly, and a cooling assembly to construct a comprehensive processing system that combines positioning, clamping, and bidirectional cooling. The initial bearing of the flange is achieved through the stable cooperation between the base and the support platform. A pipe positioner pre-fixes the pipe from above, establishing the coaxial reference of the workpiece. Subsequently, a cylinder drives the displacement of the push ring, which, via a push rod transmission, forces multiple rotating clamping plates to rotate centripetally in tandem, achieving automated and tight clamping of the flange edge. During this process, the cooperation of the adjusting block and locking block allows for adaptation to workpieces of different specifications, while the addition of friction pads ensures anti-slip and damage-free clamping of the clamping interface. Furthermore, the cooling assembly intervenes simultaneously. A gas cooling component is positioned with the rotating clamping plates to spray airflow outside the weld, while a liquid cooling component penetrates deep into the pipe. The circulating spray creates a three-dimensional heat dissipation network that coordinates internal and external cooling, effectively solving the technical problems that existing methods often struggle to ensure precise multi-degree-of-freedom adjustment while rapidly clamping, and lack a mechanism to synchronously coordinate internal and external heat dissipation paths when facing the thermal stress generated by high-temperature welding. This results in limited cooling efficiency, easily causing workpiece thermal deformation or residual stress concentration, which in turn affects the geometric accuracy and service reliability of the overall welded structure. Therefore, it avoids dimensional deviations and structural failures caused by uneven cooling, significantly improving the continuous stability of welding operations, product consistency, and overall production efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0017] Figure 1 This application provides a structural schematic diagram of a positioning fixture for metal welding. Figure 2 A schematic diagram of the left side structure of a positioning fixture for metal welding provided in this application; Figure 3 A schematic diagram of the right side structure of a positioning fixture for metal welding provided in this application; Figure 4 This is a cross-sectional structural diagram of a positioning fixture for metal welding provided in this application.

[0018] Figure Labels 1-Support assembly; 2-Clamping assembly; 3-Cooling assembly; 4-Base; 5-Support platform; 6-Pipe positioner; 7-Rotating clamp; 8-Push rod; 9-Push ring; 10-Push cylinder; 11-Gas cooling component; 12-Liquid cooling component; 13-Support cylinder; 14-Support plate; 15-Positioning component; 16-Positioning plate; 17-Rotating rod; 18-Sliding cone; 19-Second cylinder; 20-Adjusting block; 21-Clamping plate body; 22-Locking block; 23-Friction pad; 24-Connecting rod; 25-Gas nozzle; 26-Air pump; 27-Liquid nozzle; 28-Return channel; 29-Liquid pump; 30-Reservoir tank; 31-Cooler; 32-Box body; 33-Heat sink; 34-Filter screen; 35-Support plate. Detailed Implementation

[0019] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0020] First embodiment: Please see Figures 1-4 This embodiment provides a positioning fixture for metal welding, comprising a support assembly 1, a clamping assembly 2, and a cooling assembly 3. The support assembly 1 includes a base 4, a support platform 5, and a pipe locator 6. The support platform 5 is fixedly connected to the base 4 and located on top of the base 4, used to place the flange to be welded. The pipe locator 6 is positioned above the support platform 5 for pre-fixing the pipe to be welded. In this embodiment, the support assembly 1 constitutes the basic load-bearing and preliminary positioning unit of the entire fixture. The base 4, as the mounting surface, must ensure sufficient flatness and rigidity. It is typically made of cast iron or welded steel and fixed to the ground or workbench with anchor bolts to prevent vibration during welding. The support platform 5 is fixedly installed on top of the base 4, and its upper surface is precision-machined to directly support the flange to be welded, ensuring that the flange end face remains horizontal. To achieve the above-mentioned fixed connection, the support platform 5 and the base 4 can be connected by welding, bolting, or integral casting. The pipe positioner 6 is positioned above the support platform 5, with its axis coaxial with the center line of the support platform 5. It is used to pre-fix and center the pipe to be welded before clamping, ensuring the coaxiality of the pipe and the flange. The specific structural form of the pipe positioner 6 is not limited; for example, it can be a V-block, a centering chuck, or a tapered bushing with a tensioning mechanism, as long as it can achieve radial positioning of the outer or inner circle of the pipe.

[0021] The clamping assembly 2 includes multiple rotating clamps 7, multiple push rods 8, a push ring 9, and a push cylinder 10. The multiple rotating clamps 7 are rotatably mounted on the support platform 5, the push ring 9 is slidably mounted below the support platform 5, one end of each of the multiple push rods 8 is rotatably connected to the multiple rotating clamps 7, and the other end of each of the multiple push rods 8 is rotatably connected to the push ring 9. The output end of the push cylinder 10 is connected to the push ring 9.

[0022] Specifically, the clamping assembly 2 constitutes the actuator for automatically locking the flange. Rotating clamping plates 7 are evenly distributed along the circumference of the support platform 5, and are rotatably connected to the edge of the support platform 5 via hinges or pins, allowing the rotating clamping plates 7 to swing relative to the support platform 5. A push ring 9 is coaxially sleeved below the support platform 5 and can slide vertically up and down along the guide structure of the support platform 5 or the base 4. A push rod 8, as a connecting rod component, connects the rotating clamping plates 7 and the push ring 9, forming a typical crank-slider or multi-link transmission mechanism. A push cylinder 10 is vertically mounted on the base 4, and its output end (such as a piston rod) is fixedly connected to the push ring 9 to provide linear driving force. When the piston rod of the push cylinder 10 extends, it drives the push ring 9 to slide upwards. Through the transmission action of the push rod 8, it pushes each rotating clamping plate 7 to simultaneously converge towards the center, thereby radially clamping the flange edge placed on the support platform 5. Conversely, when the push cylinder 10 retracts, the push ring 9 moves downwards, pulling the rotating clamping plates 7 outwards and releasing the workpiece. It should be understood that the number of rotating clamping plates 7 can be set according to the size of the flange and the clamping force requirements, for example, three or four, evenly distributed along the circumference to ensure balanced force. In addition, although the push cylinder 10 is preferred as the power source in this embodiment, in other embodiments, hydraulic cylinders, electric push rods or servo motors with lead screw mechanisms can also be used as alternatives, as long as the reciprocating linear motion of the push ring 9 can be achieved.

[0023] The cooling assembly 3 includes a gas cooling element 11 and a liquid cooling element 12. The gas cooling element 11 is mounted on the rotating clamp 7 and is used to cool the welding position on the flange with gas. The liquid cooling element 12 is mounted on the pipe positioner 6 and is used to cool the inside of the pipe with liquid. In this structure, the cooling assembly 3 is used for rapid heat treatment of the workpiece during or after welding. The gas cooling element 11 is mounted on the rotating clamp 7 and is close to the weld area of ​​the flange, with its nozzle facing the welding position. The gas cooling element 11 can be, for example, a jet pipe or an air knife, which sprays cooling airflow onto the high-temperature weld by connecting to an external air source (such as compressed air or inert gas) to achieve rapid external cooling. The liquid cooling element 12 is integrated into the pipe positioner 6, and its cooling outlet extends into the inside of the pipe, for example, an annular spray pipe or a direct spray nozzle, to spray coolant (such as water or water-based coolant) onto the inner wall of the pipe to achieve internal cooling. This combined internal and external cooling method can effectively avoid warping deformation caused by excessively rapid cooling on one side of the workpiece. Optionally, the flow rate and pressure parameters of the gas cooling element 11 and the liquid cooling element 12 can be adjusted according to the welding process requirements, for example, by controlling the opening of the solenoid valve to adjust the flow rate of the cooling medium. Its relationship with cooling efficiency can be approximated as follows: ,in, For flow coefficient, The nozzle cross-sectional area is... For pressure difference, This refers to the fluid density. By controlling the above parameters, the cooling requirements of workpieces with different materials and thicknesses can be precisely matched, preventing the formation of hardened structures or cracks due to excessively rapid cooling.

[0024] The core innovation of this application lies in the construction of a welding positioning system that integrates mechanical positioning, multi-point linkage clamping and internal and external composite cooling. Through the structural coordination of the support components, clamping components and cooling components, the system achieves full-process automation and high-precision control from workpiece pre-fixation and automatic clamping to post-weld heat treatment.

[0025] The working process and principle of this application are as follows: First, the flange to be welded is placed on the support platform 5, and the pipe to be welded is inserted into the pipe positioner 6 to achieve initial coaxial positioning of the two; then, the push cylinder 10 is activated, which drives the push ring 9 to slide upward along the axis. The linear motion is converted into the rotational motion of the rotating clamp 7 through the push rod 8, so that multiple rotating clamps 7 swing inward synchronously and press against the outer circumference of the flange to complete the firm fixation of the workpiece; during or after welding, the gas cooling component 11 and the liquid cooling component 12 are activated simultaneously. The gas cooling component 11 sprays cooling gas onto the weld seam on the outside of the flange, and the liquid cooling component 12 sprays cooling liquid onto the inside of the pipe, forming a convective heat transfer field that removes heat from both the inside and outside.

[0026] Through the above technical solutions, this application achieves the following beneficial effects: Because a support assembly 1 with a pipe locator 6 is provided, the coaxiality of the flange and pipe before welding is ensured, solving the problem of inaccurate manual alignment and improving welding accuracy; Because a linkage clamping mechanism consisting of a push cylinder 10, a push ring 9, and a push rod 8 is adopted, automated multi-point synchronous clamping of the flange is achieved, reducing manual operation intensity and ensuring consistent clamping force, thus avoiding welding misalignment caused by uneven clamping; Because a gas cooling component 11 is provided on the rotating clamping plate 7 and a liquid cooling component 12 is provided on the pipe locator 6, a composite cooling system with internal and external synchronization is constructed, which can significantly improve the cooling efficiency of the workpiece, shorten the production cycle, and effectively prevent welding thermal deformation and residual stress caused by uneven cooling on one side, thereby ensuring the welding quality and structural stability of the final product.

[0027] Furthermore, the pipe positioner 6 includes a support cylinder 13, a support plate 14, and a positioning element 15. The support cylinder 13 is positioned above the support platform 5, the support plate 14 is connected to the output end of the support cylinder 13, and the positioning element 15 is positioned on the support plate 14 for fixing the pipe.

[0028] The support cylinder 13 serves as the driving component. Its cylinder body can be installed on the upper surface of the support platform 5 by bolting or welding, or it can be installed on the side or inside of the support platform 5 according to the actual spatial layout requirements. It is connected to the support plate 14 through a transmission mechanism, as long as it can provide a stable lifting driving force for the support plate 14. The support plate 14 is fixedly connected to the output end of the support cylinder 13, and is used to reciprocate in the vertical direction under the extension and retraction of the support cylinder 13, thereby adjusting the height position of the positioning component 15 above it. The positioning component 15 is set on the support plate 14 and is used to directly contact and support the pipe to be welded. Its specific structural form can be selected according to the specifications and material of the pipe. For example, it can be a V-block, an arc-shaped support plate, or a support structure with a flexible pad to achieve a stable pre-fixation of the pipe.

[0029] In actual operation, the support plate 14 is raised and lowered by the support cylinder 13, which can flexibly adjust the height of the positioning component 15 to facilitate the connection of the pipe and the flange.

[0030] Furthermore, the positioning component 15 includes multiple positioning plates 16, multiple rotating rods 17, a sliding cone disc 18, and a second cylinder 19. The multiple rotating rods 17 are rotatably mounted on the support plate 14. The rotating rods 17 constitute the transmission skeleton of the positioning component 15, and one end of them is mounted on the support plate 14 through a hinged structure such as a hinge seat, allowing the rotating rods 17 to swing freely around the hinge point within a certain angle range. This application innovatively adopts a multi-point linkage transmission layout, which differs from the conventional single-point or rigid clamping method. This layout can convert the single axial driving force of the second cylinder 19 into multiple radially distributed clamping forces, thereby forming a uniform mechanical constraint on the outer periphery of the pipe. This effectively solves the technical problem that traditional clamps cause the pipe to slip or deform during the clamping process due to the small contact area and concentrated force.

[0031] The positioning plate 16 is rotatably mounted on the rotating rod 17. As the actuating component that directly contacts the outer wall of the pipe, the positioning plate 16 is designed with an arc shape that adapts to the outer circumference of the pipe to maximize the contact area. In specific implementations, rubber pads or friction textures can be further added to the inner surface of the positioning plate 16 to increase the coefficient of friction and prevent slippage. The positioning plate 16 and the rotating rod 17 are also rotatably connected. This design allows the positioning plate 16 to make a slight adaptive swing (self-aligning) according to the actual flatness of the pipe surface while rotating with the rotating rod 17, ensuring that the positioning plate 16 and the outer wall of the pipe can achieve surface contact rather than line or point contact, greatly improving the stability and reliability of clamping.

[0032] A sliding conical disc 18 is slidably mounted on a support plate 14, and the output end of a second cylinder 19 is connected to the sliding conical disc 18. The sliding conical disc 18 is typically truncated cone-shaped, with its central axis perpendicular to the mounting surface of the support plate 14. The second cylinder 19, serving as a power source, is fixedly mounted on one side of the support plate 14, and its telescopic rod is arranged vertically and fixedly connected to the bottom of the sliding conical disc 18. Driven by the second cylinder 19, the sliding conical disc 18 can smoothly move up and down axially relative to the support plate 14. This structural design cleverly utilizes the conical geometric characteristics of the sliding conical disc 18, converting linear motion into rotational motion, and possesses unique advantages such as compact structure, high transmission efficiency, and no mechanical dead points.

[0033] As the sliding cone disk 18 moves upward, it pushes multiple rotating rods 17 to rotate outward, clamping the positioning plate 16 against the pipe. Specifically, when pipe fixation is required, the output rod of the second cylinder 19 extends, pushing the sliding cone disk 18 upward. The conical surface of the sliding cone disk 18 interacts with the bottom contact ends of the multiple rotating rods 17. As the sliding cone disk 18 rises, its radial dimension gradually increases, thereby generating a lateral thrust on the rotating rods 17. This thrust forces the rotating rods 17 to rotate outward about their hinge point with the support plate 14. The rotation of the rotating rods 17 further drives the positioning plates 16 to move outward synchronously until the multiple positioning plates 16 are evenly pressed against the outer circumferential wall of the pipe. During this process, the displacement of the sliding cone disk 18... Rotation angle with rotating rod 17 and the radial displacement of the positioning plate 16 There are defined geometric constraints between them.

[0034] Through the above technical solution, this application achieves efficient self-centering clamping of the positioning component 15. Due to the linkage structure of the sliding conical disc 18 with multiple sets of rotating rods 17 and positioning plates 16, when the second cylinder 19 drives the sliding conical disc 18 upward, it simultaneously pushes multiple circumferentially distributed positioning plates 16 outward synchronously, forming a clamping grip around the pipe. Unlike conventional designs, this solution utilizes the geometric characteristics of conical surface transmission to uniformly decompose the single driving force into clamping forces in multiple directions. This not only significantly increases the effective contact area between the positioning plates 16 and the pipe, avoiding pipe wall damage caused by excessive local pressure, but also effectively overcomes the slippage risk that may be caused by the pipe's own weight or welding thermal deformation, thereby significantly improving the safety and processing accuracy of welding operations.

[0035] The rotating clamp 7 includes an adjusting block 20, a clamp body 21, and a locking block 22. The adjusting block 20 is slidably mounted on the support platform 5, and the clamp body 21 is rotatably mounted on the adjusting block 20. The locking block 22 is used to lock the position of the adjusting block 20.

[0036] The adjusting block 20 serves as the mounting base for the clamping plate body 21 and is configured to reciprocate along the radial direction of the support platform 5 or a preset track. By changing the relative position of the adjusting block 20 on the support platform 5, the distance of the clamping plate body 21 relative to the flange center can be adjusted, thereby accommodating flange workpieces with different outer diameters. In specific implementations, the sliding fit structure between the adjusting block 20 and the support platform 5 can adopt common mechanical sliding fit forms such as dovetail groove guide rails, T-slot guide rails, or rectangular guide rails; this application embodiment does not impose any special limitations on this. The clamping plate body 21 is rotatably mounted on the adjusting block 20 and is used to rotate around its rotation axis under the drive of the push rod 8 to achieve the pressing or loosening action on the flange edge. The clamping plate body 21 and the adjusting block 20 can be connected by a pin, hinge, or slewing pair to ensure that the clamping plate body 21 can rotate flexibly and has sufficient load-bearing rigidity.

[0037] After the adjusting block 20 slides to the predetermined position to match the diameter of the current flange, the adjusting block 20 is fixed to the support platform 5 by operating the locking block 22. The locking block 22 can be one or more combinations of threaded fasteners, eccentric locking mechanisms, or hydraulic locking pins. This locking action can effectively prevent the adjusting block 20 from shifting due to vibration or force during subsequent clamping or welding, thereby ensuring the stability and reliability of the clamping operation.

[0038] Through the above technical solution, this application achieves the adjustable radial position of the rotating clamp 7, solving the technical problem that the fixed position of the traditional clamp makes it unsuitable for flanges of different sizes. Since the adjusting block 20 can slide and lock on the support platform 5, the operator can quickly adjust the working position of the clamp body 21 according to the actual specifications of the flange to be welded, making the positioning fixture applicable to flange welding of various specifications, significantly improving the versatility of the clamping assembly and the utilization rate of the equipment. Simultaneously, the adjustable radial position, combined with the rotational freedom of the clamp body 21, allows the clamp to more accurately conform to the flange edge contour, increasing the clamping contact area and clamping effect, thereby improving the accuracy and quality of welding positioning.

[0039] The rotating clamp 7 also includes a friction pad 23, which is fixed to the clamp body 21.

[0040] The friction pad 23 is fixedly mounted on the side surface of the clamping plate body 21 that contacts the flange. Its fixing method can be adhesive, screw connection, or snap-fit ​​connection, etc., and this embodiment does not specifically limit this method. The friction pad 23 is typically made of rubber, polyurethane, or other flexible materials with a high coefficient of friction and a certain degree of elasticity. When the clamping assembly 2 is working, the friction pad 23 directly contacts the outer circumferential surface of the flange. On the one hand, utilizing the high frictional characteristics of the friction pad 23 material itself, the frictional resistance between the clamping plate body 21 and the flange can be significantly increased, thereby effectively preventing the flange from sliding relative to the flange within the clamping plate due to external force disturbance during welding or clamping, thus improving the reliability of clamping. On the other hand, the flexible material of the friction pad 23 can form a buffer between the clamping contact surfaces, avoiding direct contact between rigid metals and causing mechanical damage such as indentations or scratches to the flange surface, thereby protecting the surface appearance quality of the flange. In addition, as a replaceable consumable part, the friction pad 23 can also reduce the direct wear of the clamping plate body 21 and extend the overall service life of the rotating clamping plate 7.

[0041] The gas cooling component 11 includes a connecting rod 24, a gas nozzle 25, and an air pump 26. The connecting rod 24 is mounted on the clamp body 21, the gas nozzle 25 is mounted on the connecting rod 24, and the air pump 26 is connected to the gas nozzle 25.

[0042] The connecting rod 24 serves as the support and extension component of the gas nozzle 25. One end is fixedly mounted on the clamping plate body 21, and the other end extends towards the weld area of ​​the flange to be welded, supporting the gas nozzle 25 in a suitable cooling position. The specific shape and length of the connecting rod 24 can be set according to the actual size and specifications of the workpiece to be welded. For example, it can be a straight rod structure or a bent rod structure with a specific bending angle to adapt to different welding angle requirements. Its material is usually selected from metal or hard plastic with a certain rigidity to ensure that it does not vibrate or deform during operation. The fixing method between the connecting rod 24 and the clamping plate body 21 can be a conventional mechanical connection method such as threaded connection, welding, or snap-fit ​​connection. This application embodiment does not make any special limitations on this.

[0043] Gas nozzle 25 is mounted on the free end of connecting rod 24 and is used to spray cooling gas delivered by air pump 26 onto the welding position on flange at a specific flow rate and angle. The shape of the nozzle 25 can be designed according to the cooling coverage requirements, such as a circular nozzle, a flat fan-shaped nozzle, or an annular nozzle, to achieve precise cooling or large-area coverage cooling of the weld area.

[0044] The air pump 26 serves as the power source for the cooling gas. Its outlet is connected to the gas nozzle 25 via a pipeline to provide cooling gas with a certain pressure and flow rate, such as compressed air, nitrogen, or other inert gases. The position of the air pump 26 can be flexibly adjusted according to the overall layout of the fixture. It can be mounted on the clamping plate body 21 or the connecting rod 24 for movement, or it can be mounted on a fixed component such as the base and connected via a flexible pipeline. With the above configuration, the gas cooling component 11 can accurately and stably deliver the cooling gas to the high-temperature welding zone. Combined with the clamping action of the clamping plate body 21, it ensures timely and uniform cooling of the weld during or after welding, thereby effectively improving the metallographic structure of the heat-affected zone and enhancing the mechanical properties and product quality of the welded joint.

[0045] The liquid cooling component includes a liquid nozzle 27, a return channel 28, a liquid pump 29, a liquid storage tank 30, and a cooler 31. The liquid nozzle 27 is mounted on a rotating rod 17. As the final actuation component for the coolant, the liquid nozzle 27 atomizes or jets the coolant from the liquid pump 29, directly applying it to the inner wall surface of the pipe to be welded. The mounting position of the liquid nozzle 27 on the rotating rod 17 can be adjusted according to the pipe diameter and cooling requirements. For example, it can be positioned near the center of the pipe, or multiple nozzles can be distributed along the length of the rotating rod 17 to achieve uniform coverage. The nozzle shape can be a flat fan shape, a cone shape, or a circle, etc., preferably one that can cover the main heated area of ​​the inner wall of the pipe; this application does not impose any special limitations on this.

[0046] Liquid pump 29 is connected to liquid nozzle 27 and liquid reservoir 30. As the power source for the circulation system, liquid pump 29 drives the coolant to flow in the pipeline. Specifically, the suction port of liquid pump 29 is connected to liquid reservoir 30 via a pipeline, and the discharge port is connected to liquid nozzle 27 via a pipeline. During operation, liquid pump 29 provides a pressure differential to draw the cryogenic coolant from liquid reservoir 30 and deliver it to liquid nozzle 27. According to fluid mechanics principles, the head and flow rate provided by liquid pump 29 must overcome pipeline resistance losses and meet the injection pressure requirements; its operating characteristics can be expressed as follows:

[0047] in, This refers to the actual head of the liquid pump. Zero flow head (i.e., shut-off head). Volumetric flow rate, This is a characteristic coefficient related to the pump body structure and pipeline resistance. Appropriate selection ensures the coolant has sufficient flow velocity and impact force to remove heat. The liquid pump 29 can be a centrifugal pump, gear pump, or plunger pump, depending on the coolant viscosity and system pressure range.

[0048] The return channel 28 is located below the support platform 5 and communicates with the storage tank 30. The return channel 28 forms the passage for the coolant to return to the storage tank after heat exchange. During welding, the coolant sprayed onto the inner wall of the pipe absorbs heat and its temperature rises. Under the action of gravity or residual pressure, it flows to the bottom of the pipe and then returns to the storage tank 30 via the return channel 28. Unlike conventional designs that directly discharge coolant, resulting in waste, this application innovatively designs the return channel 28 to construct a recycling path. The return channel 28 is typically located at the bottom of the support platform 5 and can be a collection tank or a guide pipe structure. Its cross-sectional dimensions should be sufficient to accommodate the maximum instantaneous return flow to prevent overflow. This design not only maintains a clean working environment but also achieves coolant recycling, significantly reducing production costs.

[0049] A cooler 31 is mounted on the liquid storage tank 30 to cool the tank. As a key component for maintaining the system's thermal balance, the cooler 31 cools the returning high-temperature coolant, restoring it to a low-temperature state suitable for effective heat absorption. The cooler 31 can be an air-cooled radiator (including heat sinks and a fan) or a water-cooled heat exchanger. In this embodiment, the cooler 31 is mounted on the liquid storage tank 30, meaning it can directly exchange heat with the liquid inside the tank or be integrated into the tank wall. The heat dissipation power of the cooler 31 should match the heat generated during welding; its heat balance equation can be expressed as:

[0050] in, This refers to the amount of heat that needs to be removed per unit of time. The specific heat capacity of the coolant. For quality flow, This refers to the temperature difference before and after the coolant flows through the cooler. Through proper configuration, the coolant temperature in the reservoir 30 is ensured to remain within the optimal operating range, thereby guaranteeing continuous and efficient cooling capacity and preventing cooling failure due to excessive temperature.

[0051] In summary, the liquid pump 29, liquid nozzle 27, return channel 28, liquid storage tank 30, and cooler 31 together constitute a closed-loop liquid circulation system. The liquid pump 29 drives the cryogenic coolant into the pipeline for heat exchange. After absorbing heat, the liquid automatically returns to the liquid storage tank 30 via the return channel 28, where it is further cooled by the cooler 31. This design overcomes the limitations of traditional single-pass or open-loop cooling systems. The continuous operation of the cooler 31 ensures a constant coolant temperature, solving the problems of poor internal pipeline circulation and low heat dissipation efficiency. Simultaneously, the return channel 28 enables resource recovery, offering advantages in cost savings and environmental protection.

[0052] The liquid storage tank 30 includes a tank body 32 and multiple heat sinks 33, with the multiple heat sinks 33 distributed on the tank body 32.

[0053] The housing 32 serves as a sealed container for storing the cooling medium. An internal cavity is formed to hold the liquid, and this cavity is connected to the liquid pump 29 and the return channel 28, forming part of the cooling circulation loop. The housing 32 is typically made of a metal material with good thermal conductivity, such as aluminum alloy or copper alloy, to facilitate rapid heat transfer from the interior to the outer wall. The specific shape of the housing 32 can be designed according to installation space and capacity requirements; for example, it can be cylindrical, cuboid, or other irregularly shaped structures. This embodiment does not impose any special limitations on this.

[0054] Multiple heat sinks 33 are vertically or at a specific angle protruding from the outer wall surface of the housing 32. Their main function is to significantly increase the surface area of ​​the liquid storage tank 30 in contact with the surrounding ambient air. By setting multiple heat sinks 33, the effective heat dissipation area is increased. The surface area is much larger than that of the smooth casing 32, thus significantly improving the overall heat dissipation capacity without changing the power of the cooler 31. The heat sinks 33 can be arranged in a uniform array on the housing 32, or they can be densely arranged locally according to the distribution of the fluid temperature field inside the housing 32. For example, a denser arrangement of heat sinks can be made near the inlet of the return channel 28 to specifically enhance heat exchange in that area. In addition, the shape of the heat sinks 33 can be flat, corrugated, or needle-like, and their material can be integrally formed with the housing 32, or they can be fixedly connected to the outer wall of the housing 32 by welding, brazing, or mechanical assembly.

[0055] Through the above technical solution, this application effectively improves the heat dissipation performance of the liquid storage tank 30. Because multiple heat sinks 33 are distributed on the tank body 32, the heat exchange area of ​​the liquid storage tank 30 is greatly expanded, allowing the coolant to quickly dissipate heat to the surrounding air through the tank body 32 wall and the heat sinks 33 after flowing back to the liquid storage tank 30. This structural design not only shares the cooling load of the cooler 31 and reduces system energy consumption, but also prevents the coolant from overheating and reducing its cooling effect due to long-term circulation and heat accumulation, ensuring the stability and reliability of the cooling system during continuous welding operations. Furthermore, this structure is simple and compact, requires no additional power drive, and achieves efficient heat dissipation using natural convection or ambient airflow, offering advantages such as low cost, convenient maintenance, and reliable operation.

[0056] The housing also includes a filter screen 34 and a support plate 35. The support plate 35 is slidably connected to the housing 32 and is located at the inlet of the housing 32. The filter screen 34 is mounted on the support plate 35.

[0057] The support plate 35, as a movable component supporting the filter screen 34, has a sliding connection that allows it to move linearly in and out relative to the housing 32, thus enabling quick assembly and disassembly of the filter screen 34. This sliding connection structure can be achieved by using a slide rail and a slider, or by using a sliding fit where the side wall of the housing 32 has a groove and the edge of the support plate 35 is embedded in the groove. The specific implementation of this application does not impose any particular limitation on this embodiment.

[0058] The filter screen 34 is used to physically intercept and filter impurities such as welding slag and metal fragments in the coolant as it flows back into the tank 32, preventing impurities from accumulating at the bottom of the reservoir 30 or entering the liquid pump 29 and causing blockage. The mesh size of the filter screen 34 can be reasonably selected according to the size of common impurity particles in the coolant. For example, it can be a metal filter screen between 40 and 200 mesh, or a composite filter screen with a multi-layer filtration structure, as long as it meets the filtration accuracy requirements. Through the above settings, impurities carried by the liquid are effectively blocked by the filter screen 34 during the coolant circulation process, thereby ensuring the cleanliness of the coolant, preventing the liquid nozzle 27 from failing due to blockage, and ensuring a stable and reliable cooling effect of the liquid cooling component 12 on the inside of the pipe.

[0059] When the coolant returns to the housing 32 via the return channel 28, it must first pass through the filter screen 34 located at the inlet. Impurities are trapped on the filter screen 34, while the clean liquid enters the housing 32 for storage. This structural design effectively solves the technical problem of coolant accumulating impurities and causing nozzle clogging in existing technologies, significantly improving the operational stability and service life of the liquid cooling system. Furthermore, since the support plate 35 is slidably connected to the housing 32, when excessive impurities accumulate on the filter screen 34 requiring cleaning or replacement, the operator only needs to slide the support plate 35 off the housing 32 to remove the filter screen 34 entirely for maintenance. After maintenance, it can be pushed back in to resume operation. The entire process does not require disassembling the housing 32 or other pipelines, greatly improving the convenience and efficiency of equipment maintenance.

[0060] Second Embodiment This application also provides a method for using a positioning fixture for metal welding. This method is implemented based on any of the aforementioned embodiments of the positioning fixture for metal welding. Through a standardized operating procedure, the pipe and flange are precisely positioned, clamped, and welded. Cooling is performed simultaneously after welding, thereby achieving high-efficiency and high-quality metal welding processing.

[0061] A positioning fixture for metal welding using any one of the above embodiments.

[0062] When using this method, first place the flange to be welded on the support platform of the support assembly and adjust its position to match the alignment requirements of the pipeline. Then, place the pipeline to be welded into the pipeline positioner, and use the support and tensioning action of the pipeline positioner to pre-fix the pipeline, ensuring that the pipeline end face fits tightly with the flange.

[0063] After the workpiece is positioned, the push cylinder of the clamping assembly is activated, driving the push ring to slide below the support platform. The movement of the push ring is transmitted to the corresponding rotating clamping plate through multiple push rods, driving the rotating clamping plate to rotate inward. During rotation, the rotating clamping plate gradually approaches the outer edge of the flange, and the flange is firmly fixed to the support platform by mechanical clamping force, preventing relative displacement during welding. Once the workpiece is securely clamped, conventional metal welding processes can be performed to perform circumferential welding at the connection between the pipe and the flange.

[0064] During or after welding, the cooling system is activated according to cooling requirements. On one hand, cooling gas is sprayed onto the welding area of ​​the flange via a gas cooling component. The airflow carries away heat from the weld and heat-affected zone, achieving rapid cooling and reducing oxidation. On the other hand, coolant is sprayed into the inside of the pipe via a liquid cooling component. The coolant absorbs heat from the pipe's inner wall and flows back to the storage tank via a return channel. Within the storage tank, it is circulated and cooled again before participating in heat exchange. This dual gas-liquid cooling mechanism effectively controls the temperature distribution in the welding area, reduces workpiece thermal deformation, and shortens cooling time, thereby significantly improving the overall efficiency and processing quality of the welding operation.

[0065] The above-disclosed embodiments are merely one or more preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art can understand that all or part of the processes for implementing the above embodiments and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.

Claims

1. A positioning fixture for metal welding, characterized in that, It includes a support assembly, a clamping assembly, and a cooling assembly. The support assembly includes a base, a support platform, and a pipe positioner. The support platform is fixedly connected to the base and located on top of the base for placing the flange to be welded. The pipe positioner is disposed above the support platform for pre-fixing the pipe to be welded. The clamping assembly includes multiple rotating clamping plates, multiple push rods, a push ring, and a push cylinder. The multiple rotating clamping plates are rotatably mounted on the support platform. The push ring is slidably mounted below the support platform. One end of each of the multiple push rods is rotatably connected to the multiple rotating clamping plates, and the other end of each push rod is rotatably connected to the push ring. The output end of the push cylinder is connected to the push ring. The cooling assembly includes a gas cooling component and a liquid cooling component. The gas cooling component is disposed on the rotating clamp plate and is used to cool the welding position on the flange with gas. The liquid cooling component is disposed on the pipe positioner and is used to cool the inside of the pipe with liquid.

2. The positioning fixture for metal welding as described in claim 1, characterized in that, The pipe positioner includes a support cylinder, a support plate, and a positioning element. The support cylinder is located above the support platform, the support plate is connected to the output end of the support cylinder, and the positioning element is located on the support plate for fixing the pipe.

3. A positioning fixture for metal welding as described in claim 2, characterized in that, The positioning component includes multiple positioning plates, multiple rotating rods, a sliding cone disk, and a second cylinder. The multiple rotating rods are rotatably mounted on the support plate, and the positioning plates are rotatably mounted on the rotating rods. The sliding cone disk is slidably mounted on the support plate. The output end of the second cylinder is connected to the sliding cone disk. When the sliding cone disk moves upward, it pushes the multiple rotating rods to rotate outward to clamp the positioning plate against the pipe.

4. A positioning fixture for metal welding as described in claim 3, characterized in that, The rotating clamp includes an adjusting block, a clamp body, and a locking block. The adjusting block is slidably disposed on the support platform, the clamp body is rotatably disposed on the adjusting block, and the locking block is used to lock the position of the adjusting block.

5. A positioning fixture for metal welding as described in claim 4, characterized in that, The rotating clamp also includes a friction pad, which is fixed to the clamp body.

6. A positioning fixture for metal welding as described in claim 5, characterized in that, The gas cooling component includes a connecting rod, a gas nozzle, and an air pump. The connecting rod is mounted on the clamping plate body, the gas nozzle is mounted on the connecting rod, and the air pump is connected to the gas nozzle.

7. A positioning fixture for metal welding as described in claim 6, characterized in that, The liquid cooling component includes a liquid nozzle, a return channel, a liquid pump, a storage tank, and a cooler. The liquid nozzle is mounted on the rotating rod. The liquid pump is connected to the liquid nozzle and the storage tank. The return channel is located below the support platform and is connected to the storage tank. The cooler is mounted on the storage tank and is used to cool the storage tank.

8. A positioning fixture for metal welding as described in claim 7, characterized in that, The liquid storage tank includes a tank body and multiple heat sinks, with the multiple heat sinks distributed on the tank body.

9. A positioning fixture for metal welding as described in claim 8, characterized in that, The housing also includes a filter screen and a support plate. The support plate is slidably connected to the housing and located at the entrance of the housing. The filter screen is disposed on the support plate.

10. A method of using a positioning fixture for metal welding, characterized in that, The positioning fixture for metal welding described in any one of claims 1-9 is adopted.

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