Automatic welding system and welding method for saddle-shaped welding seam of reactor internals outlet pipe nozzle

Abstract

The invention discloses an automatic welding system and method for a saddle-shaped weld joint of an outlet pipe nozzle of a reactor internals, the system comprises a hanging basket assembly, a welding robot and a welding workstation, a plurality of mounting seats are arranged on the side wall of the outlet pipe nozzle of the hanging basket assembly, and the welding robot is directly fixed to a workpiece through the mounting seats; automatic welding of saddle-shaped welding seams on the inner side and the outer side of the outlet pipe nozzle can be achieved. The welding robot is provided with a welding seam locating and tracking mechanism, a molten pool monitoring system, a water-cooling TIG welding gun and a multi-angle wire feeding mechanism, the welding seam track can be automatically recognized, the welding process is tracked in real time, and parameters are adjusted in a self-adaptive mode. The welding work station integrates the functions of control, power supply, cooling and the like, and whole-process monitoring and data recording are achieved. According to the method, the problems of unstable quality, low efficiency, high labor intensity and the like of traditional manual welding are solved through the technical means of a staggered arc starting strategy, automatic locating tracking, parameter self-adaptive adjustment and the like, the welding quality and the production efficiency are remarkably improved, and the labor intensity is reduced.

Description

Technical Field

[0001] This invention relates to the field of welding technology for nuclear reactor internals, specifically an automatic welding system and method for saddle-shaped welds on the outlet nozzles of internals. Background Technology

[0002] In-reactor components are among the core components of a nuclear reactor. They are complex in structure, large in size, and require extremely high manufacturing precision and welding quality. The outlet nozzle, as an important part of the in-reactor basket assembly, typically forms a saddle-shaped circumferential weld with the reactor core. The welding quality of this weld directly affects the safety and reliability of reactor operation.

[0003] In existing technologies, the saddle-shaped weld between the outlet nozzle and the cylinder is mostly completed using manual TIG welding or manual arc welding. Because the saddle-shaped weld is a spatial curve with constantly changing bevel position and angle, the welder needs to continuously adjust the angle and position of the welding torch during the welding process, making the operation difficult and labor-intensive. Furthermore, the quality of manual welding is highly dependent on the welder's skill level; key indicators such as weld formation, penetration depth, and weld width fluctuate significantly, easily leading to defects such as incomplete penetration, undercut, porosity, and slag inclusions, resulting in a high weld rework rate.

[0004] Another problem is low welding efficiency. Due to the complexity of saddle-shaped welds, manual welding usually requires multiple layers and passes, resulting in long welding cycles and difficulty in improving production efficiency. At the same time, because the welding position is limited, welders must maintain unnatural postures in confined spaces, which not only affects welding stability but also increases operational risks.

[0005] In recent years, with the development of automated welding technology, some manufacturing sectors have begun to use welding robots to complete complex welds. However, in the manufacturing of nuclear reactor internals, due to the large size of the workpieces, their special structures, high cleanliness requirements, and the fact that the welding position is located inside the basket assembly, conventional industrial robots are difficult to apply directly. Furthermore, the technical challenges of spatial trajectory recognition, real-time tracking, and adaptive adjustment of welding parameters for saddle-shaped welds have not yet been fully resolved. Therefore, the application of automated welding in this field still faces significant challenges. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide an automatic welding system and method for saddle-shaped welds on the outlet nozzles of reactor internal components, in order to solve the problems of unstable quality, low efficiency and high labor intensity of existing manual welding. It realizes automatic identification and tracking of weld trajectory, adaptive adjustment of welding parameters and real-time monitoring of the process, and achieves the technical effects of improving welding quality and efficiency, reducing labor intensity and ensuring the reliability of nuclear safety grade component manufacturing.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an automatic welding system for saddle-shaped welds of outlet nozzles of in-core components, including a basket assembly, wherein multiple mounting seats are provided circumferentially on the side wall of the outlet nozzle of the basket assembly; It also includes a welding robot and a welding workstation. The welding workstation is used to control the welding robot, which is installed in a mounting seat on the side wall of the outlet nozzle of the suspended platform assembly and performs welding operations on the inside and outside of the outlet nozzle. The welding robot includes a robot body, and the bottom of the robot body is provided with a robot mounting frame adapted to the mounting base, as well as a welding head and a welding head control box.

[0008] In a preferred embodiment, the welding head includes a water-cooled TIG welding torch, and a manual wire feed angle adjustment mechanism is provided on one side of the water-cooled TIG welding torch; The welding head also includes a weld seam positioning and tracking mechanism and a molten pool monitoring system.

[0009] In a preferred embodiment, the weld seam positioning and tracking mechanism is a laser contour sensor, and the molten pool monitoring system is a vision camera; The weld seam positioning and tracking mechanism is used to monitor and provide a basis for correcting the welding torch position during the welding process; The molten pool monitoring system is used to monitor the molten pool morphology in real time.

[0010] In a preferred embodiment, the welding head is equipped with an anti-collision sensor. When the anti-collision sensor encounters abnormal resistance, the control system cuts off the power to the welding head and causes it to retract.

[0011] In a preferred embodiment, the robot body is equipped with a hoisting mechanism.

[0012] In a preferred embodiment, the welding workstation includes a system control console, a robot control cabinet, a power supply assembly, a sensor control box, a cooling system, and a temporary robot support for temporarily placing the welding robot.

[0013] In a preferred embodiment, the welding workstation and the welding robot interact via wireless or wired communication, enabling remote control of the welding process, real-time display of welding status, and storage of welding logs.

[0014] The welding method based on the above-mentioned automatic welding system for the saddle-shaped weld of the outlet nozzle of the in-core component includes the following steps: S1. Assemble and position the outlet nozzle of the suspended platform assembly to the cylinder body, and control the misalignment to be no more than 0.5mm; S2. Install the welding robot in place, adjust its level and coaxiality, and complete the tool center point TCP calibration; S3. Use the weld seam positioning and tracking mechanism to scan the saddle-shaped weld seam groove and automatically generate a three-dimensional welding path; S4. Based on the bevel size and material properties, preset the welding current, voltage, welding speed, wire feed speed, shielding gas flow rate and oscillation parameters on the system control panel. S5. Start the welding program. The welding robot performs multi-layer and multi-pass welding according to the preset path, and adopts an interlaced arc initiation strategy, rotating 180° to initiate the arc every two layers. S6. Monitor the molten pool morphology and temperature in real time through the molten pool monitoring system, and adaptively adjust welding parameters based on feedback; S7. After each layer of welding is completed, the interlayer temperature is checked. If it exceeds the preset value, the system will automatically wait for the temperature to drop. S8. Remove temporary attachments, clean the weld surface, and conduct visual inspection and non-destructive testing.

[0015] In the preferred embodiment, the staggered arc-starting strategy described in S5 is as follows: the first layer starts the arc from the 0° position, the second layer starts the arc from the 180° position, the third layer starts the arc from the 90° position, the fourth layer starts the arc from the 270° position, and this sequence is repeated until the bevel is filled.

[0016] In the preferred embodiment, the adaptive adjustment described in S6 includes: When the width of the weld pool is less than the preset value, increase the welding current or decrease the welding speed. When the width of the weld pool is greater than the preset value, reduce the welding current or increase the welding speed.

[0017] The automatic welding system and welding method for the saddle-shaped weld seam of the outlet nozzle of the in-core component provided by the present invention have the following beneficial effects by adopting the above structure and method: (1) The weld trajectory is automatically identified and tracked in real time through the weld positioning and tracking mechanism. Combined with the parameter adaptive adjustment function, the molten pool shape is stable and the forming is uniform, effectively reducing defects such as incomplete penetration, undercut, and porosity. Compared with traditional manual welding, the weld quality consistency is greatly improved, meeting the strict quality requirements of nuclear safety grade components. (2) Automated multi-layer and multi-pass welding replaces manual operation. Combined with staggered arc initiation strategy and continuous welding process, the welding cycle is significantly shortened. Workers only need to monitor and intervene. They do not need to maintain an uncomfortable posture for a long time, which greatly reduces labor intensity and operational risks. At the same time, it reduces non-productive time and improves equipment utilization. (3) The modular design and replaceable positioning accessories enable the system to adapt to different specifications of outlet nozzles, and the multi-angle wire feeding mechanism can adapt to complex bevel shapes. Key parameters are automatically recorded during the welding process to form a complete quality file, which facilitates subsequent auditing and traceability and meets the strict management requirements of nuclear safety manufacturing. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the overall structure of the welding robot installed inside the component in this invention.

[0019] Figure 2 This is a schematic diagram of the overall structure of the welding robot when it is installed outside the component in this invention.

[0020] Figure 3 This is a schematic diagram of the welding robot structure of the present invention.

[0021] Figure 4 This is a schematic diagram of the welding head structure of the present invention.

[0022] Figure 5 This is a schematic diagram of the welding workstation structure of the present invention.

[0023] In the diagram: 1. Suspended platform assembly; 2. Mounting base; 3. Welding robot; 4. Welding workstation; 5. Robot body; 6. Welding head; 7. Lifting mechanism; 8. Head control box; 9. Robot mounting frame; 10. Anti-collision sensor; 11. Water-cooled TIG welding torch; 12. Molten pool monitoring system; 13. Manual wire feed angle adjustment mechanism; 14. Weld seam positioning and tracking mechanism; 15. System control console; 16. Robot control cabinet; 17. Power supply assembly; 18. Sensor control box; 19. Cooling system; 20. Robot temporary support. Detailed Implementation

[0024] Example 1: like Figure 1-2 In the present invention, an automatic welding system for saddle-shaped weld seams of outlet nozzles of in-core components includes a basket assembly 1, wherein a plurality of mounting seats 2 are provided circumferentially on the side wall of the outlet nozzle of the basket assembly 1. It also includes a welding robot 3 and a welding workstation 4. The welding workstation 4 is used to control the welding robot 3. The welding robot 3 is installed in the mounting seat 2 on the side wall of the outlet nozzle of the basket assembly 1 and performs welding operations on the inside and outside of the outlet nozzle. The welding robot 3 includes a robot body 5, and the bottom of the robot body 5 is provided with a robot mounting frame 9 adapted to the mounting base 2, as well as a welding head 6 and a welding head control box 8.

[0025] Preferred solutions include Figure 3 In the middle, the welding head 6 includes a water-cooled TIG welding torch 11, and a manual wire feeding angle adjustment mechanism 13 is provided on one side of the water-cooled TIG welding torch 11; The welding head 6 also includes a weld seam positioning and tracking mechanism 14 and a molten pool monitoring system 12.

[0026] In a preferred embodiment, the weld seam positioning and tracking mechanism 14 is a laser contour sensor, and the molten pool monitoring system 12 is a vision camera; The weld seam positioning and tracking mechanism 14 is used to monitor and provide a basis for correcting the welding torch position during the welding process; The molten pool monitoring system 12 is used to monitor the molten pool morphology in real time.

[0027] Preferred solutions include Figure 4 In the process, the welding head 6 is equipped with an anti-collision sensor 10. When the anti-collision sensor 10 encounters abnormal resistance, the control system cuts off the power to the welding head 6 and causes it to retract.

[0028] In a preferred embodiment, the robot body 5 is equipped with a hoisting mechanism 7.

[0029] Preferred solutions include Figure 5 The welding workstation 4 includes a system control console 15, a robot control cabinet 16, a power supply assembly 17, a sensor control box 18, a cooling system 19, and a temporary robot support 20 for temporarily placing the welding robot 3.

[0030] In a preferred embodiment, the welding workstation 4 and the welding robot 3 communicate wirelessly or via wired communication to achieve data interaction, enabling remote control of the welding process, real-time display of the welding status, and storage of welding logs.

[0031] Example 2: The welding method of the automatic welding system for the saddle-shaped weld of the outlet nozzle of the in-core component, as described in Example 1, includes the following steps: S1. Assemble and position the outlet nozzle of the suspended platform assembly 1 to the cylinder body, and control the misalignment to be no more than 0.5mm; S2. Install the welding robot 3 into place, adjust its level and coaxiality, and complete the tool center point TCP calibration; S3. Use the weld seam positioning and tracking mechanism 14 to scan the saddle-shaped weld seam groove and automatically generate a three-dimensional welding path. S4. Based on the bevel size and material properties, preset the welding current, voltage, welding speed, wire feed speed, shielding gas flow rate and oscillation parameters on the system control panel 15. S5. Start the welding program. Welding robot 3 performs multi-layer and multi-pass welding according to the preset path, and adopts an interlaced arc initiation strategy, rotating 180° to initiate the arc every two layers. S6. The molten pool morphology and temperature are monitored in real time by the molten pool monitoring system 12, and the welding parameters are adaptively adjusted according to the feedback. S7. After each layer of welding is completed, the interlayer temperature is checked. If it exceeds the preset value, the system will automatically wait for the temperature to drop. S8. Remove temporary attachments, clean the weld surface, and conduct visual inspection and non-destructive testing.

[0032] In the preferred embodiment, the staggered arc-starting strategy described in S5 is as follows: the first layer starts the arc from the 0° position, the second layer starts the arc from the 180° position, the third layer starts the arc from the 90° position, the fourth layer starts the arc from the 270° position, and this sequence is repeated until the bevel is filled.

[0033] In the preferred embodiment, the adaptive adjustment described in S6 includes: When the width of the weld pool is less than the preset value, increase the welding current or decrease the welding speed. When the width of the weld pool is greater than the preset value, reduce the welding current or increase the welding speed.

[0034] Example 3: Based on the welding method described in Example 2, its practical application can be divided into the following continuous stages: Equipment deployment, welding execution, special working condition handling, and post-weld inspection are as follows: 1. Equipment Deployment Phase During the device deployment phase, the outlet nozzle of the suspended platform assembly 1 is first assembled with the cylinder and tack welded. The misalignment is strictly controlled within the allowable range. Simultaneously, the bevel and both sides are thoroughly cleaned to remove oxide scale, oil, and other impurities, ensuring that the welding quality is not affected by surface condition. Subsequently, several mounting seats 2 are installed circumferentially on the side wall of the outlet nozzle. Appropriate mounting seats are selected based on the welding position requirements to fix the robot mounting frame 9. A horizontal adjustment mechanism ensures that the coaxiality error between the robot body and the nozzle is controlled within a minimal range.

[0035] Welding workstation 4 is positioned at a suitable distance from the workpiece, ensuring stable and reliable communication and cable connections. After system connection is complete, a comprehensive inspection of the water cooling system 19, protective gas pipeline, robot control cabinet 16, and sensor control box 18 is required to confirm that all components are functioning correctly. The welding robot 3 is then hoisted onto the mounting base and secured using a hoisting mechanism. Tool center point calibration is performed to establish a precise workpiece coordinate system, laying the foundation for subsequent automated welding.

[0036] 2. Welding execution stage Taking the welding of the outer saddle-shaped weld as an example, the weld positioning and tracking mechanism 14 is first activated to perform a complete scan of the weld. The system automatically generates a three-dimensional welding path and displays it on the system console 15. The operator can preview the path and perform collision detection through the offline simulation function to ensure no interference risk. Then, welding parameters are preset according to the bevel size and material properties, including current, voltage, welding speed, wire feed speed, and shielding gas flow rate, and an alternating arc initiation strategy is set, that is, alternating arc initiation in the order of 0°, 180°, 90°, and 270° to reduce heat concentration and welding deformation.

[0037] During the welding process, welding robot 3 automatically executes the welding task according to a preset path. Weld seam tracking mechanism 14 detects the weld seam position in real time and corrects the welding torch posture, compensating for deviations caused by assembly errors and thermal deformation. Molten pool monitoring system 12 continuously monitors the molten pool morphology, and the system adaptively adjusts welding parameters based on the detection results to ensure uniform forming and good fusion. After each layer of welding is completed, the system automatically detects the interpass temperature, pausing welding if necessary to allow cooling and prevent overheating from affecting weld quality. Throughout the entire welding process, key parameters are recorded and stored in real time, providing a basis for subsequent quality traceability.

[0038] 3. Handling of special working conditions For welding the inner saddle-shaped weld, the welding robot 3 needs to be reinstalled on the corresponding mounting base 2 inside the nozzle, and its posture adjusted to suit the needs of working in confined spaces. The wire feeding position is optimized using the manual wire feeding angle adjustment mechanism 13 to ensure good sidewall fusion. Considering the poor heat dissipation conditions on the inner side, the welding heat input is appropriately reduced, and the molten pool is closely monitored to prevent welding defects caused by limited operating space.

[0039] For special working conditions such as large-diameter, thick-walled nozzles, the number of mounting bases 2 can be increased to improve robot stability. A segmented, multi-layer welding process is adopted, with an intermediate inspection performed after each weld at a certain angle, and the interlayer temperature is strictly controlled to prevent welding deformation. In extremely confined spaces, a more compact welding head 6 can be used, with optimized motion trajectory, small-step multi-segment path planning, and anti-collision protection function enabled to ensure a safe and reliable welding process.

[0040] 4. Post-weld inspection stage After welding, the temporary mounting accessories are first removed, and the mounting base is repaired by welding and grinding. Spatter and slag on the weld surface are cleaned to ensure a neat weld appearance. A comprehensive quality inspection is then conducted, including visual inspection, ultrasonic testing, and penetrant testing, to ensure that the internal and surface quality of the weld meets the stringent requirements for nuclear safety grade components. Finally, the welding process parameter records are exported and saved, establishing a complete quality traceability archive. Welding curves are analyzed to optimize subsequent process parameters, and the three-dimensional welding path is saved to provide a reference for the production of similar products.

[0041] In addition, safety precautions should be prioritized throughout the entire operation process. Protective shields should be installed to prevent arc flash injuries, and operators should wear necessary personal protective equipment. After each use, the sensor lens should be cleaned promptly, the welding torch wear should be checked, the TCP should be calibrated regularly, and the program and parameters should be backed up to ensure long-term stable system operation.

[0042] This application achieves automated, high-quality welding of saddle-shaped welds through a series of meticulously designed process steps and technical measures, significantly improving the efficiency and reliability of nuclear reactor internals manufacturing.

Claims

1. An automatic welding system for saddle-shaped weld seams of outlet nozzles of in-core components, comprising a basket assembly (1), characterized in that: The outlet nozzle sidewall of the suspended basket assembly (1) is provided with multiple mounting seats (2) in the circumferential direction. It also includes a welding robot (3) and a welding workstation (4), the welding workstation (4) being used to control the welding robot (3), the welding robot (3) being installed in a mounting seat (2) on the side wall of the outlet nozzle of the basket assembly (1) and performing welding operations on the inside and outside of the outlet nozzle; The welding robot (3) includes a robot body (5), and the bottom of the robot body (5) is provided with a robot mounting frame (9) adapted to the mounting base (2), as well as a welding head (6) and a head control box (8).

2. The automatic welding system for saddle-shaped weld seams of in-core component outlet nozzles according to claim 1, characterized in that: The welding head (6) includes a water-cooled TIG welding torch (11), and a manual wire feeding angle adjustment mechanism (13) is provided on one side of the water-cooled TIG welding torch (11). The welding head (6) also includes a weld seam positioning and tracking mechanism (14) and a molten pool monitoring system (12).

3. The automatic welding system for the saddle-shaped weld seam of the outlet nozzle of the in-core component according to claim 2, characterized in that: The weld seam positioning and tracking mechanism (14) is a laser contour sensor, and the molten pool monitoring system (12) is a vision camera; The weld seam positioning and tracking mechanism (14) is used to monitor and provide a basis for correcting the welding torch position during the welding process; The molten pool monitoring system (12) is used to monitor the molten pool morphology in real time.

4. The automatic welding system for saddle-shaped weld seams of in-core component outlet nozzles according to claim 2, characterized in that: The welding head (6) is equipped with an anti-collision sensor (10). When the anti-collision sensor (10) is subjected to abnormal resistance, the control system cuts off the power to the welding head (6) and causes it to retract.

5. The automatic welding system for the saddle-shaped weld seam of the outlet nozzle of the in-core component according to claim 1, characterized in that: The robot body (5) is equipped with a hoisting mechanism (7).

6. The automatic welding system for saddle-shaped weld seams of in-core component outlet nozzles according to claim 1, characterized in that: The welding workstation (4) includes a system control console (15), a robot control cabinet (16), a power supply assembly (17), a sensor control box (18), a cooling system (19), and a temporary robot support (20) for temporarily placing the welding robot (3).

7. The automatic welding system for the saddle-shaped weld seam of the outlet nozzle of the in-core component according to claim 6, characterized in that: The welding workstation (4) and the welding robot (3) interact via wireless or wired communication, enabling remote control of the welding process, real-time display of welding status, and storage of welding logs.

8. A welding method for an automatic welding system for saddle-shaped weld seams of in-core component outlet nozzles according to any one of claims 1-7, characterized in that... Includes the following steps: S1. Assemble and position the outlet nozzle of the suspended platform assembly (1) to the cylinder body, and control the misalignment to be no more than 0.5mm; S2. Install the welding robot (3) in place, adjust its level and coaxiality, and complete the tool center point TCP calibration; S3. Use the weld seam positioning and tracking mechanism (14) to scan the saddle-shaped weld seam groove and automatically generate a three-dimensional welding path; S4. Based on the bevel size and material properties, preset the welding current, voltage, welding speed, wire feed speed, shielding gas flow rate and oscillation parameters on the system control panel (15); S5. Start the welding program. The welding robot (3) performs multi-layer and multi-pass welding according to the preset path. It adopts an interleaved arc-starting strategy and rotates 180° to start the arc every two layers. S6. Monitor the molten pool morphology and temperature in real time through the molten pool monitoring system (12), and adjust the welding parameters adaptively based on the feedback; S7. After each layer of welding is completed, the interlayer temperature is checked. If it exceeds the preset value, the system will automatically wait for the temperature to drop. S8. Remove temporary attachments, clean the weld surface, and conduct visual inspection and non-destructive testing.

9. The welding method of the automatic welding system for the saddle-shaped weld seam of the outlet nozzle of the in-core component according to claim 7, characterized in that: The staggered arc-starting strategy described in S5 is as follows: the first layer starts the arc from the 0° position, the second layer starts the arc from the 180° position, the third layer starts the arc from the 90° position, the fourth layer starts the arc from the 270° position, and this sequence is repeated until the bevel is filled.

10. The welding method of the automatic welding system for the saddle-shaped weld seam of the outlet nozzle of the in-core component according to claim 8, characterized in that: The adaptive adjustment described in S6 includes: When the width of the weld pool is less than the preset value, increase the welding current or decrease the welding speed. When the width of the weld pool is greater than the preset value, reduce the welding current or increase the welding speed.

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