Methods, systems, and readable storage media for welding a nuclear island containment steel liner

Abstract

The application discloses a kind of nuclear island containment steel lining welding method, system and storage medium, involve nuclear power plant welding technical field, comprising: wallboard is matched with ring vertical back rib angle steel and is spot welded;Three-dimensional model is imported into welding system, reads model structure, size and spatial position information, sets theoretical reference point;Robot end TCP is accurately positioned to steel lining cylinder wall;Welding system automatically distributes weld discontinuity rule and extracts minimum welding node, and sends welding track to robot control system;In the welding system, steel lining cylinder wall is divided into nodes, each node sets scanning order and ring vertical back rib angle steel welding parameter;Robot carries out welding torch trajectory planning according to the set welding order and parameter;Robot is according to the welding order set by welding system and the welding parameter stored and starts arc welding.The welding method solves the technical problems of low efficiency, wrong and missed welding of manual welding of steel lining, low programming efficiency and complex operation of traditional robot welding.

Description

Technical Field

[0001] This invention relates to the field of welding technology for nuclear power plant facilities, and in particular to a welding method, system, and readable storage medium for the steel lining of the containment vessel of a nuclear island. Background Technology

[0002] The containment steel liner is a steel plate of a certain thickness attached to the inner surface of the containment. The containment steel liner belongs to the QA1 quality assurance level and II safety level nuclear safety equipment, and its welds are all butt welds with full penetration. Structurally, the steel liner mainly consists of four parts: the base plate, the haunch area, the cylinder wall, and the dome. The dome is the sealing part of the reactor building's containment steel liner (e.g., ...). Figure 1 As shown, it has a spherical hyperboloid shell shape.

[0003] Chinese invention patent CN115430940A discloses a welding method, system, and readable storage medium for the steel liner of a nuclear island containment vessel. The welding method includes the following steps: controlling a mobile beveling machine to process the bevel of the steel liner plate, ensuring the straightness of the bevel; controlling the laser bevel angle within a first preset angle range; controlling the laser bevel assembly gap within a first preset distance range; setting a first preset current, a first preset welding speed, and a first oscillation parameter; performing laser tracking calibration; using a ceramic plate as a backing plate and a mixture of argon and carbon dioxide as a shielding gas for welding; and performing non-destructive testing to verify the weld quality after welding. This welding method for the steel liner of the nuclear island containment vessel improves on-site steel liner welding efficiency, reduces welding deformation and defects, increases the on-site welding pass rate, reduces welding fumes, improves the welder's working environment, and has the advantages of good weld quality and high welding efficiency.

[0004] However, the traditional robotic welding method mentioned above is teach-in programming welding. The position of each key point of the robot is determined by the operator's eyes, and each weld seam needs to be programmed. For non-standard large curved segmented welding structures, this is time-consuming. Each unit module needs to be programmed (about 500 segmented weld seams), the programming workload is huge, it cannot meet the production cycle requirements, and it requires high operator skills.

[0005] Secondly, while offline programming robots can be programmed offline, they are difficult to adapt to changes in tooling and workpiece welding deformation, especially for thin-walled welding structures where significant deformation may occur during the welding process. This necessitates real-time adjustments to the robot's welding trajectory, which does not meet the requirements of practical applications.

[0006] Finally, for the welding of numerous segmented fillet welds in such large thin-walled curved surface segmented structures, traditional welding methods suffer from low efficiency, easy mis-welding, and missed welding; traditional robot welding teaching programming is inefficient and complex to operate, making it unsuitable. Summary of the Invention

[0007] In view of this, the purpose of this invention is to address the problems and shortcomings of the existing technology by providing a welding method, system and readable storage medium for the steel lining of the nuclear island containment vessel, so as to solve the technical problems of low efficiency, easy mis-welding and missed welding of the steel lining back rib unit module by manual welding, as well as low programming efficiency and complex operation of traditional robot welding technology.

[0008] To solve the above problems, the present invention adopts the following technical solution: The first objective of this invention is to provide a welding method for the steel liner of a nuclear island containment vessel, the welding method comprising the following steps: Step S 100 : Actual assembly of steel-lined cylinder wall units; The wall panel is assembled with the circumferential back rib angle steel and the vertical back rib angle steel, and then fixed by semi-automatic flux-cored wire gas shielded welding spot welding. Step S 200 Importing 3D models; The three-dimensional model of the containment steel liner is imported into the intelligent welding system. The intelligent welding system reads the structural, dimensional and spatial relative position information of the three-dimensional model of the containment steel liner and sets the theoretical reference point of the containment steel liner. Step S 300 The steel-lined cylinder wall is precisely positioned using the robot's end effector TCP. The welding system automatically assigns weld discontinuity rules and extracts the minimum welding node, and sends the automatically generated welding trajectory and parameters to the robot control system. Step S 400 Model processing and parameter settings In the welding system, the imported steel lining cylinder wall is divided into nodes, each node being a small steel lining back rib surrounding unit. The scanning sequence, circumferential back rib angle steel welding parameters, and vertical back rib angle steel welding parameters are set for each steel lining back rib surrounding unit. Step S 500 The robot plans the welding torch trajectory according to the set welding sequence and parameters. Before reaching the node welding, the laser vision camera accurately finds the position of the initial point to be welded. Step S 600 Robotic automated welding; The robot initiates welding according to the welding sequence set by the welding system and the stored welding parameters, until all welds are completed.

[0009] Preferably, in step S 100Among them, the assembly gap between the circumferential back rib angle steel, the vertical back rib angle steel and the wall panel is controlled within a first preset distance range, the first preset distance being 0mm to +1mm.

[0010] Preferably, in step S 100 The welding parameters for the vertical back rib angle steel are set as follows: The first welding current is 140A~155A, the first welding voltage is 21-26V, the first welding speed is 2.4mm / s~2.6mm / s, the first oscillation amplitude is 1.5-2.5mm, and the first oscillation speed is 10mm~30mm / s; The welding parameters for the circumferential back rib angle steel are set as follows: The second welding current is 168A to 185A, the second welding voltage is 21-26V, the second welding speed is 2.9mm / s to 3.1mm / s, the second oscillation amplitude is 1.5-2.5mm, and the second oscillation speed is 10mm to 30mm / s.

[0011] Preferably, in step S 200 The step of precisely positioning the steel-lined cylinder wall using the robot's end effector TCP includes: Determine a relatively stable position for BP0 detection on the display screen, and adjust the up, down, left, and right keys on the remote control to center the weld seam in the image window, with the laser line about 5mm to 10mm to the left of the vertical "+" line in the image window; The welding torch is fixed above the center of the weld and is positioned above the surface of the steel lining cylinder wall; Mark points under the laser for data acquisition; After collecting the preset number of marker points, turn off the calibration function.

[0012] Preferably, the parameters for the semi-automatic flux-cored wire gas shielded welding are set as follows: The welding wire used is φ1.2mm E501T-1, the shielding gas is ≥99.9% CO2, the spot welding current is 195-205A, the spot welding voltage range is 26.5-27.6V, and the gas flow rate is 16-25L / min.

[0013] Preferably, in step S 200 The method for precisely positioning the steel-lined cylinder wall using the robot's end effector TCP includes: Step S 210 : Obtain the spatial coordinates [x] of the reference point of the circumferential angle steel i ,y i ,z i ]; Step S 220The position coordinates of the robot end effector TCP in the robot coordinate system are obtained by using the transformation matrix [R(δ),T(δ)] between the robot coordinate system and the robot tool coordinate system. Step S 230 : The spatial coordinates of the reference point of the circumferential angle steel [x i ,y i ,z i The theoretical reference point is assigned to the 3D model of the circumferential angle steel to unify the spatial position of the 3D model and the physical circumferential angle steel.

[0014] Preferably, in step S 300 The specific steps for extracting the smallest weld node include: The welding system analyzes and identifies the geometric features of the 3D model to determine the welding area and the boundaries of each welding node; Based on the shape of the 3D model and the welding rules, the welding system divides the welding area into multiple smaller nodes; The welding system uses automated algorithms to extract the smallest welding node from the entire welding area and assigns corresponding welding parameters to the smallest welding node.

[0015] Preferably, in step S 300 The specific steps for automatically allocating weld interruptions include: The extra-long, non-welded parts of the hoisting components in the 3D model are pre-cut to achieve standardized specifications. Analyze and calculate the welding line position at the connection between the angle steel and the arc base plate; According to the fixed placement rules of angle steel, determine the starting reference point of angle steel, and the welds on both sides of angle steel are arranged alternately; When intersecting with the angle steel weld, the staggered welding rule is continued to generate the reference discontinuity rule and displayed on the three-dimensional model; Observe whether the baseline discontinuity rule is reasonable. If there is no problem, after extracting the smallest welding node, perform global allocation according to the baseline discontinuity rule.

[0016] The second objective of this invention is to provide a welding system for the steel liner of the nuclear island containment vessel, which employs the welding method for the steel liner of the nuclear island containment vessel described above. The welding system includes two symmetrically distributed nine-axis cantilever welding robots, a laser vision camera, flexible tooling, a welding power source arranged on a ground rail platform, a wire feeding system installed on the nine-axis cantilever welding robots, and a cleaning station. Each of the nine-axis cantilever welding robots includes a cantilever that is slidably mounted on the ground rail at the bottom and a six-axis welding robot, wherein the six-axis welding robot is hung upside down on the cantilever. The flexible fixture is made of steel pipes of different lengths and fasteners connected together, and the curved surface of the steel lining to be welded is placed on the flexible fixture. The laser vision camera is mounted on the welding torch of the six-axis welding robot; The laser vision camera, the welding power source, the wire feeding system, and the cleaning station are all electrically connected to the nine-axis cantilever welding robot.

[0017] A third objective of the present invention is to provide a readable storage medium storing a computer program that, when executed by a processor, implements the steps of the welding method for the steel liner of the nuclear island containment vessel as described above.

[0018] Compared with the prior art, the present invention has significant advantages and beneficial effects, specifically reflected in the following aspects: 1. The welding method for the containment steel liner of the nuclear island in this application includes the following steps: Assembling the wall panel with the circumferential back rib angle steel and the vertical back rib angle steel, and fixing them by semi-automatic flux-cored wire gas shielded welding; importing the three-dimensional model of the containment steel liner into the welding system, the welding system reading the structural, dimensional, and spatial relative position information of the containment steel liner, and setting the theoretical reference points of the containment steel liner; precisely positioning the steel liner cylinder wall through the robot's end effector TCP, completing the assembly of the steel liner cylinder wall units, wherein each steel liner cylinder wall unit module consists of a wall panel and the circumferential back rib angle steel and the vertical back rib angle steel. The process involves dividing the imported steel lining cylinder wall unit module into nodes within the welding system. Each node is a small steel lining back rib surrounding unit. A scanning sequence, circumferential back rib angle steel welding parameters, and vertical back rib angle steel welding parameters are set for each steel lining back rib surrounding unit. Laser tracking calibration is performed. The intelligent welding system automatically generates scanning and welding trajectories and sends them to the robot body. The robot body plans the welding torch trajectory according to the set welding sequence and parameters. Before reaching the node for welding, the laser vision camera accurately locates the initial welding point and performs welding according to the initial task.

[0019] 2. No teaching programming is required. The robot can accurately locate the weld seam to be welded by importing the model and using laser vision, thus achieving automatic programming of the robot.

[0020] 3. It is highly adaptable and suitable for welding various types of large curved multi-segment back rib structures, breaking through the functions that traditional teaching robots and offline programming robots cannot achieve; 4. Improve welding efficiency by automatically planning the welding torch posture and trajectory, and welding while scanning, thereby improving welding efficiency and quality. Attached Figure Description

[0021] Figure 1 This is a schematic flowchart of the welding method for the steel liner of the nuclear island containment vessel in an embodiment of the present invention; Figure 2 This is a front view schematic diagram of the containment steel liner structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of a typical structure of a steel-lined unit module without through-holes in an embodiment of the present invention; Figure 4 This is a schematic diagram of a typical steel lining unit module structure including a through-hole component in an embodiment of the present invention; Figure 5 This is a schematic diagram of the welding system structure of the steel liner of the nuclear island containment vessel in an embodiment of the present invention; Figure 6 This is a schematic diagram of the node distribution structure of the steel-lined cylinder wall unit module in an embodiment of the present invention; Figure 7 This is a schematic diagram illustrating the configuration of a single node in an embodiment of the present invention; Figure 8 This is a schematic diagram of the steel lining E03 unit module in an embodiment of the present invention; Figure 9 This is a schematic diagram of the P-point positioning of the three-dimensional model of the steel lining E03 unit module in an embodiment of the present invention; Figure 10 This is a schematic diagram of node partitioning in an embodiment of the present invention; Figure 11 This is a schematic diagram of the welding sequence of the steel-lined cylinder wall in an embodiment of the present invention; Figure 12 This is a schematic diagram illustrating the staggered fillet weld arrangement requirements in an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures: 1-Steel liner of containment building; 10-Steel liner cylinder wall unit; 11-Wall panel; 12-Circumferential back rib angle steel; 13-Vertical back rib angle steel; 100 - Nine-axis cantilever welding robot; 200 - Laser vision camera; 300 - Flexible tooling; 400 - Welding power source; 500 - Welding torch cleaning station; Detailed Implementation To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, many specific details are set forth to provide a comprehensive understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this application. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components. All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0023] The accompanying drawings show some block diagrams and / or flowcharts. It should be understood that some blocks or combinations thereof in the block diagrams and / or flowcharts can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when executed by the processor, these instructions can create means for implementing the functions / operations described in these block diagrams and / or flowcharts.

[0024] The containment steel liner of a nuclear power reactor building mainly consists of four parts: the base plate, the haunch area, the cylindrical wall, and the dome. The steel liner unit module is a typical thin-walled curved surface structure. The circumferential and vertical back rib angle steel distributed on it divides the entire curved surface into multiple closed or semi-closed segmented structures. The weld seam is a segmented staggered weld seam, and the weld seam length of a single steel liner unit module is approximately 120 meters.

[0025] Because the weld distribution on the steel lining unit module is relatively complex, the requirements for welding deformation are high. The overall deformation of the containment steel lining component must not exceed ±20mm / 1m, and the weld size control requirements are strict (length tolerance not exceeding 20mm, weld leg size not exceeding 2mm).

[0026] In addition, the back ribs on the curved surface are connected to the wall panel by staggered fillet welds with a weld leg size of 6mm. The length of the staggered weld of the circumferential large angle steel is 380mm, and the length of the staggered weld of the vertical small angle steel is 400mm.

[0027] In existing technologies, the welding of the angle steel back ribs of steel linings uses semi-automatic gas-shielded welding with flux-cored wire, which has low welding efficiency and high labor intensity for welders. At peak times, the number of welders involved is around 10. In addition, due to the varying skill levels of welders, the weld quality fluctuates greatly, and post-weld grinding is generally required to meet the requirements. More importantly, incomplete welds and incorrect welds are prone to occur.

[0028] On the other hand, the traditional robot welding method is teach-in programming welding. The position of each key point of the robot is determined by the operator's eyes. Each weld seam needs to be programmed. For non-standard large curved segmented welding structures, this is time-consuming. Each unit module needs to be programmed (about 500 segmented weld seams). The programming workload is huge, which cannot meet the production cycle requirements and requires high operator skills.

[0029] Although offline programming robots can be programmed offline, they are difficult to adapt to changes in tooling and workpiece welding deformation, especially for thin-walled welding structures, where the welding process may involve significant deformation, requiring real-time adjustment of the robot's welding trajectory, which does not meet the needs of practical applications.

[0030] For welding numerous segmented fillet welds in large, thin-walled, curved segmented structures such as steel-lined unit modules, traditional manual welding suffers from low efficiency, proneness to incorrect welding and missed welds, while traditional robotic welding suffers from low teaching-programming efficiency, complex operation, and inapplicability. Please refer to [link to relevant documentation]. Figure 1-12 As shown, this embodiment of the invention provides a welding method for the steel liner of a nuclear island containment vessel, the welding method comprising the following steps: Step S 100 : 10 actual steel-lined cylinder wall units; The wall panel 11 is assembled with the circumferential back rib angle steel 12 and the vertical back rib angle steel 13, and then fixed by semi-automatic flux-cored wire gas shielded welding spot welding.

[0031] In this step, pre-spot welding ensures that the relative position between the wall panel 11 and the back rib angle steel is accurate, laying the foundation for high-quality welding in the future. This effectively avoids welding defects caused by inaccurate assembly and positioning, such as misaligned welds and improper gaps, thereby improving the quality of the welded joint and the precision of the overall structure.

[0032] Step S 200 Importing 3D models; The three-dimensional model of the containment steel liner 1 is imported into the welding system. The welding system reads the structural, dimensional and spatial relative position information of the three-dimensional model of the containment steel liner 1, and sets the theoretical reference point of the containment steel liner 1. In this step, the welding system can directly import the 3D model of the steel liner generated by TEKLA and automatically read the geometric structure, dimensions, and spatial relative position information of the steel liner. Through this process, the welding system can efficiently obtain the 3D shape and position of the steel liner, providing accurate data support for subsequent welding path planning and trajectory generation.

[0033] After the 3D model is imported into the welding system, users can manually or automatically select three reference points through a vision camera to calibrate the spatial position of the steel liner. These reference points are usually feature points on the surface of the steel liner that have fixed positions and calibrated significance, which can help the welding system determine the precise position of the steel liner in actual space.

[0034] Step S 200 The steel-lined cylinder wall is precisely positioned using the robot's end effector TCP. It's important to explain that the Tool Center Point (TCP) at the robot's end effector (tool) is a point on that end effector. This point is fundamental for the robot's motion control and path planning. When no tool is attached to the robot's end effector, the TCP point is the end of the robot body, specifically the center point of the sixth-axis flange. When a tool (such as a welding torch on a welding robot or a spray gun on a painting robot) is attached to the end effector, the TCP point shifts to the tool's end effector, becoming the origin of the tool's coordinate system. By setting and calibrating the TCP, the accuracy and repeatability of the robot during task execution can be ensured.

[0035] Step S 300 The welding system automatically assigns weld discontinuity rules and extracts the minimum welding nodes, and sends the automatically generated welding trajectory and parameters to the robot control system.

[0036] In this step, precise positioning makes the welding process more accurate and controllable. The robot can weld strictly according to the preset trajectory and parameters, avoiding errors caused by human operation, ensuring the quality of the weld formation, including more uniform parameters such as weld width, height, and penetration depth, improving the performance and reliability of the welded joint, and thus enhancing the welding quality of the entire nuclear island containment steel liner structure.

[0037] Step S 400 Model processing and parameter settings In the intelligent welding system, the imported steel lining cylinder wall is divided into nodes. Each node is a small steel lining back rib surrounding unit. The scanning sequence, welding parameters of the circumferential back rib angle steel 12 and the welding parameters of the vertical back rib angle steel 13 are set for each steel lining back rib surrounding unit.

[0038] In this step, the robot has already determined the welding sequence and corresponding parameters of each node before welding, which reduces the time wasted due to parameter adjustment and welding sequence decision-making during the welding process, further improves welding efficiency, and realizes efficient and automated production of the welding process.

[0039] Step S 500The robot plans the welding torch trajectory according to the set welding sequence and parameters. Before reaching the node welding, the laser vision camera accurately finds the position of the initial point to be welded. Step S 600 Robotic automated welding; The robot initiates welding according to the welding sequence set by the welding system and the stored welding parameters, until all welds are completed.

[0040] Therefore, in the entire welding process, from importing the 3D model, dividing nodes and setting parameters, planning welding trajectories, to automated welding, most steps are completed automatically by intelligent welding systems and robots, reducing the need for human intervention. This reduction in human intervention lowers the risk of welding quality problems and safety accidents caused by human error or improper operation, improving the reliability and safety of the welding process, which is crucial for engineering structures like the nuclear island containment vessel, which have extremely high safety requirements. Compared to traditional manual welding methods, this significantly shortens welding time, increases welding efficiency, and allows more welding tasks to be completed in the same amount of time, thus accelerating the construction progress of the steel lining of the nuclear island containment vessel.

[0041] In the embodiments of this invention, please refer to Figure 2 As shown, the diameter of the steel liner of the nuclear island containment vessel is 42.8 meters. The cylindrical wall of the steel liner is divided into 9 sections. Each of the 9 sections consists of 10 steel liner unit modules. Each steel liner unit module is welded together with a 6mm thick Q265HR steel plate, longitudinal back rib angle steel, transverse back rib angle steel, and φ8mm*80mm anchoring studs. The steel liner unit module is a typical thin-walled curved surface structure. The transverse and vertical angle steel back ribs distributed on it divide the entire curved surface into multiple closed or semi-closed segmented structures. The material of the longitudinal and transverse back rib angle steel is Q235B. The longitudinal back rib angle steel has a specification of L75*50*8mm, and the transverse back rib angle steel has a specification of L125*80*10mm.

[0042] Specifically, in step S 100 Among them, the assembly gap between the circumferential back rib angle steel 12, the vertical back rib angle steel 13 and the wall panel 11 is controlled within a first preset distance range, which is 0mm to +1mm.

[0043] Proper assembly gap helps prevent welding defects. Too small a gap can lead to insufficient filler metal, causing incomplete penetration; too large a gap can result in excessive filler metal, causing undercut and burn-through. By controlling the gap within the range of 0mm to +1mm, the amount of filler metal in the weld can be ensured, reducing welding defects and improving the quality of the welded joint.

[0044] In the steel lining of the nuclear island containment vessel, structural stability is crucial for ensuring safe operation. By controlling the gaps within a preset range, welding stress and deformation can be reduced, improving the precision and stability of the structure, thereby enhancing the overall safety of the structure.

[0045] Specifically, in step S 100 The welding parameters for the vertical back rib angle steel 13 are set as follows: The first welding current is 140A~155A, the first welding voltage is 21-26V, the first welding speed is 2.4mm / s~2.6mm / s, the first oscillation amplitude is 1.5-2.5mm, and the first oscillation speed is 10mm~30mm / s; The welding parameters for the circumferential back rib angle steel 12 are set as follows: The second welding current is 168A to 185A, the second welding voltage is 21-26V, the second welding speed is 2.9mm / s to 3.1mm / s, the second oscillation amplitude is 1.5-2.5mm, and the second oscillation speed is 10mm to 30mm / s.

[0046] Therefore, by setting specific parameters such as welding current, voltage, speed, oscillation amplitude, and oscillation speed, the welding process can be precisely controlled to ensure welding quality. For example, setting the welding current of the vertical back rib angle steel 13 within the range of 140A to 155A can ensure the weld penetration and forming quality; setting the welding voltage within the range of 21-26V can ensure that the width and height of the weld are appropriate; and setting the welding speed within the range of 2.4mm / s to 2.6mm / s can avoid welding defects such as undercut and incomplete penetration.

[0047] In addition, different combinations of welding parameters can optimize the welding process and improve the performance of the welded joint. For example, the welding current of the circumferential back rib angle steel 12 is set in the range of 168A to 185A, which is slightly higher than the welding current of the vertical back rib angle steel 13. This can better meet the welding requirements of the circumferential back rib angle steel 12 and improve the strength and toughness of the weld. The welding speed is set in the range of 2.9mm / s to 3.1mm / s, which is slightly faster than the welding speed of the vertical back rib angle steel 13. This can improve welding efficiency while ensuring welding quality.

[0048] Specifically, in step S 200 The step of precisely positioning the steel-lined cylinder wall using the robot's end effector TCP includes: Determine a relatively stable position for BP0 detection on the display screen, and adjust the up, down, left, and right keys on the remote control to center the weld seam in the image window, with the laser line about 5mm to 10mm to the left of the vertical "+" line in the image window; The welding torch is fixed above the center of the weld and is positioned above the surface of the steel lining cylinder wall; Mark points under the laser for data acquisition; After collecting the preset number of marker points, turn off the calibration function.

[0049] After the steel lining unit modules are assembled and inspected, considering the large curved surface size of the steel lining unit modules and the positional deviation during the hoisting process, it is necessary to perform precise positioning through the robot's end effector TCP. The positioning can be based on the three spatial position points of the circumferential large angle steel.

[0050] Specifically, the parameter settings for the semi-automatic flux-cored wire gas shielded welding are as follows: The welding wire used is φ1.2mm E501T-1. E501T-1 is a titanium oxide type CO2 gas-shielded flux-cored welding wire with excellent welding process performance, a soft and stable arc, minimal spatter, easy slag removal, and aesthetically pleasing weld formation. It is suitable for flat and horizontal welding, can perform all-position welding, and has high welding efficiency.

[0051] The shielding gas is ≥99.9% CO2. CO2 gas can form a stable arc during welding, making the welding process smoother, reducing spatter and defects, and improving welding quality and efficiency.

[0052] The spot welding current is 195-205A, and the spot welding voltage range is 26.5-27.6V. This provides a suitable heat input, allowing the welding wire to melt and fill the weld, resulting in a good weld formation. Excessive current may cause the weld to overheat, producing defects such as burn-through and undercut; insufficient current may lead to incomplete weld filling, producing defects such as incomplete penetration and porosity. A suitable spot welding voltage can maintain a stable arc, reduce arc fluctuations and interruptions, and improve the stability and reliability of the welding process.

[0053] The gas flow rate is 16-25 L / min, providing sufficient protective gas to cover the weld area, effectively preventing oxygen and nitrogen from the air from entering the molten pool, reducing porosity and oxidation in the weld, and improving the purity and mechanical properties of the weld.

[0054] Specifically, please refer to Figure 6 , 7 As shown in steps S, 8, and 9, in step S 200 The method for precisely positioning the steel-lined cylinder wall using the robot's end effector TCP includes: Step S 210 : Obtain the spatial coordinates [x] of the reference point of the circumferential angle steel i ,y i ,z i ].

[0055] In this step, by obtaining the actual spatial coordinates of the circumferential angle steel reference point, the physical entity is transformed into digital data, avoiding subjective errors in traditional manual measurement and significantly improving the positioning accuracy of the reference point.

[0056] Step S 220 The position coordinates of the robot end effector TCP in the robot coordinate system are obtained by using the transformation matrix [R(δ),T(δ)] between the robot coordinate system and the robot tool coordinate system.

[0057] In this step, a transformation matrix is ​​used to achieve dynamic mapping between the robot coordinate system and the tool coordinate system, ensuring that the position of the end effector TCP is accurately expressed in the global coordinate system and reducing the cumulative error caused by coordinate system deviation.

[0058] Step S 230 : The spatial coordinates of the reference point of the circumferential angle steel [x i ,y i ,z i The theoretical reference point is assigned to the 3D model of the circumferential angle steel to unify the spatial position of the 3D model and the physical circumferential angle steel.

[0059] In this step, the coordinates of the measured reference points are assigned to the theoretical points in the 3D model, achieving seamless alignment between the virtual model and the actual installation position, and providing a high-precision reference for subsequent operations (such as welding and assembly).

[0060] Therefore, by using data-driven positioning and model-physical fusion, the accuracy, efficiency, and reliability of steel-lined cylinder wall installation have been significantly improved, while providing a scalable technical framework for intelligent construction. Future work requires further optimization of sensor robustness and enhancement of model adaptability to address more complex engineering needs.

[0061] Specifically, in step S 300 The specific steps for extracting the smallest weld node include: Step 1: The welding system analyzes and identifies the geometric features of the 3D model to determine the welding area and the boundaries of each welding node; This step begins by analyzing the geometry of the steel lining to identify key welding areas requiring focused control. The boundaries of each weld joint are determined by identifying weld joints, angle variations, and weld types. Identifying and marking weld joints, angle variations, potential weld paths, and other geometric features affecting the welding process within the steel lining primarily involves the following aspects: a. Angle change detection: Identify joints and welded areas by calculating the change in the normal to the steel lining surface.

[0062] b. Joint type classification: Identify and mark butt joints, corner joints, etc. on the steel lining.

[0063] c. Weld path identification: The start and end points of the weld are determined by identifying the connecting lines between welding areas.

[0064] Step 2: Based on the shape of the 3D model and the welding rules, the welding system divides the welding area into multiple smaller nodes.

[0065] In this step, each node can be a weld segment or multiple adjacent weld segments, through area division.

[0066] Specifically, the welding system determines how to divide the smallest weld joint using an "enclosure" method, which mainly falls into the following categories: a. Applicable situations for four-sided enclosure: Applicable to regular and enclosed welding areas, such as large flat areas, or areas surrounded on four sides by objects or existing welds.

[0067] Implementation method: By finding all boundary lines that intersect with the welding area, the system identifies a complete closed area whose four boundaries are completely surrounded by objects or existing welds.

[0068] Algorithm implementation: Use the convex hull algorithm or polygon splitting algorithm to detect and confirm closed regions.

[0069] b. Application of three-sided enclosure: Applicable to certain areas that are only enclosed by three boundaries, such as the seams between connecting parts, or areas that are open on one side.

[0070] Implementation method: The system identifies areas that are only enclosed on three sides by detecting the boundaries of the welding area. These areas are usually located at the joints of the workpiece or where there is a gap between two parts.

[0071] Algorithm implementation: The connected component analysis algorithm in graph theory can be used to identify which regions are connected to the external regions, ensuring that only the regions enclosed on three sides are extracted.

[0072] c. Application of two-sided enclosure: Suitable for workpieces with complex geometries, such as areas with two boundaries restricted by other components and the other two sides open.

[0073] Implementation method: The system analyzes the welding area on the workpiece and identifies those areas that are surrounded by objects on two sides and open on two sides, which is applicable to irregularly shaped welding nodes.

[0074] Algorithm implementation: Use spatial segmentation algorithm or geometry-based scan line algorithm to analyze the shape of the workpiece and identify the area enclosed by two sides.

[0075] Step 3: The welding system extracts the smallest welding node from the entire welding area using an automated algorithm and assigns corresponding welding parameters to the smallest welding node.

[0076] Therefore, for each smallest welding node, the welding system automatically generates a welding path based on its geometric characteristics, heat input control requirements, and welding sequence. The welding path will be shortened as much as possible and excessive repetitive operations will be avoided; the welding trajectory will be optimized within each welding node to ensure that the robot welds along the optimal path, thereby improving welding efficiency and reducing robot movement time.

[0077] It should be explained that extracting the smallest weld node refers to the welding system automatically extracting the smallest weld node from the overall welding area based on the geometry of the workpiece and welding requirements. These nodes are the basic areas for precise control and operation during the welding process, and typically consist of one or more weld segments.

[0078] Specifically, in step S 300 The specific steps for automatically assigning weld discontinuity rules include: Step 1: Cut and pre-process the extra-long non-welded parts of the hoisting components in the 3D model to achieve standardized specifications.

[0079] In this step, the model is first processed by pre-processing (cutting) the extra-long, unwelded parts of the small angle steel (used for component hoisting) and making them consistent with the specifications of other small angle steels to avoid affecting the weld seam allocation rules.

[0080] Step 2: Analyze and calculate the welding line position at the connection between the angle steel and the arc base plate; In this step, the position of the welding line is calculated by analyzing the connection points of the large angle steel, small angle steel and other component flat plates (arc base plates) (taking the maximum value of "left and right").

[0081] Step 3: Determine the starting reference point of the angle steel according to the fixed placement rules, and arrange the welds on both sides of the angle steel in an alternating manner.

[0082] In this step, the large angle steel welds are spaced at 380mm intervals, and the small angle steel welds are spaced at 400mm intervals.

[0083] Step 4: When intersecting with the angle steel weld, continue the staggered welding rule to generate the reference discontinuity rule and display it on the 3D model.

[0084] Step 5: Observe whether the baseline discontinuity rule is reasonable. If there is no problem, after extracting the smallest welding node, perform global allocation according to the baseline discontinuity rule.

[0085] Therefore, the welding system automatically assigns welds to each area in the model that needs to be welded based on the welding rules and the geometric data of the steel lining. The length, shape, type and welding direction of each weld segment are intelligently assigned by the system according to the structural and process requirements.

[0086] Please see Figure 5 As shown, this embodiment of the invention also provides a welding system for the steel liner of the nuclear island containment vessel, which adopts the welding method for the steel liner of the nuclear island containment vessel described above. The welding system includes two symmetrically distributed nine-axis cantilever welding robots 100, a laser vision camera 200, a flexible tooling 300, a welding power source 400 arranged on a ground rail platform, a wire feeding system installed on the nine-axis cantilever welding robot 100, and a cleaning station 500. Each set of the nine-axis cantilever welding robot 100 includes a cantilever 110 that is slidably mounted on the ground rail 600 at the bottom and a six-axis welding robot 120, wherein the six-axis welding robot 120 is hung upside down on the cantilever 110. The flexible fixture 300 is made of steel pipes and fasteners of different lengths, and the steel lining curved surface segments to be welded are placed on the flexible fixture 300. The laser vision camera 200 is mounted on the welding torch of the six-axis welding robot 120; The laser vision camera 200, the welding power supply 400, the wire feeding system, and the cleaning station 500 are all electrically connected to the nine-axis cantilever welding robot 100.

[0087] In a specific embodiment of the present invention, the welding system comprises two symmetrically distributed nine-axis cantilever welding robots 100, a laser vision camera 200, a flexible fixture 300, a welding power source 400 arranged on a ground rail platform 600, a wire feeding system mounted on the nine-axis cantilever welding robots 100, and a torch cleaning station 500. Each nine-axis cantilever welding robot 100 specifically includes one six-axis welding robot 120, with the other three axes including a cantilever X-axis, a lateral movement Y-axis, and a ground rail 600 for X-axis movement. The six-axis welding robot 120 is suspended upside down on the cantilever 110, the welding power source 400 is arranged on a platform on the ground rail 600, and the platform can move with the ground rail. The torch cleaning station 500 is arranged on a column. The curved surface of the steel lining to be welded is placed in segments on the flexible fixture 300, which is composed of steel pipes of different lengths connected by fasteners. Curved surfaces of different diameters can be assembled from flexible fixtures of different lengths.

[0088] For the sake of welding efficiency, the entire welding system can simultaneously store two steel lining curved surface segments (dual-station distribution) in the length direction to achieve collaborative operation between robots and humans.

[0089] The specific working process of the welding system for the steel lining of the nuclear island containment vessel is as follows: First, the welding system imports the 3D model of the steel lining and, combined with a high-precision laser vision camera, accurately identifies the surface of the steel lining and the position of the weld. The laser vision camera can efficiently scan the surface of the steel lining, capture the position and size of the weld in real time, and match it with the 3D model data. This process not only ensures the accuracy of the geometric information of the steel lining, but also accurately calibrates the actual position of the weld before welding.

[0090] Next, by combining the 3D model of the steel lining and real-time weld inspection data, the welding system can automatically generate the optimal welding trajectory. The welding system uses intelligent algorithms to plan the path, optimize the welding path and welding angle, and adapt to different workpiece shapes and weld positions.

[0091] Finally, the robot will automatically adjust its movement based on the calculated welding trajectory and posture to ensure the quality of each weld.

[0092] Therefore, this welding system enables factories to achieve efficient, precise, and automated welding operations, reducing manual intervention and improving welding quality and production efficiency. At the same time, the welding system is highly adaptable, capable of being flexibly adjusted according to different workpieces and welding requirements to meet the needs of various production scenarios.

[0093] In addition, to achieve the above objectives, embodiments of the present invention also provide a readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the welding method for the steel liner of the nuclear island containment as described above.

[0094] The readable storage medium can be a memory in a welding system, or at least one of ROM (Read-Only Memory) / RAM (Random Access Memory), magnetic disk, optical disk, etc. The readable storage medium includes several instructions to cause a terminal device with a processor to execute the methods of the various embodiments of the present invention.

[0095] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the scope of protection of this invention.

Claims

1. A welding method for the steel liner of a nuclear island containment vessel, characterized in that, The welding method for the steel liner of the nuclear island containment vessel includes the following steps: Step S 100 : Actual assembly of steel-lined cylinder wall units; The wall panel is assembled with the circumferential back rib angle steel and the vertical back rib angle steel, and then fixed by semi-automatic flux-cored wire gas shielded welding spot welding. Step S 200 Importing 3D models; The three-dimensional model of the containment steel liner is imported into the welding system. The welding system reads the structural, dimensional and spatial relative position information of the three-dimensional model of the containment steel liner and sets the theoretical reference point of the containment steel liner. Step S 300 The steel-lined cylinder wall is precisely positioned using the robot's end effector TCP. The welding system automatically assigns weld discontinuity rules and extracts the minimum welding node, and sends the automatically generated welding trajectory and parameters to the robot control system. Step S 400 Model processing and parameter settings; In the welding system, nodes are divided for the imported steel lining cylinder wall, and the scanning sequence, circumferential back rib angle steel welding parameters, and vertical back rib angle steel welding parameters are set for each steel lining back rib surrounding unit. Step S 500 The robot plans the welding torch trajectory according to the set welding sequence and parameters. Before reaching the node welding, the laser vision camera accurately finds the position of the initial point to be welded. Step S 600 Robotic automated welding; The robot initiates welding according to the welding sequence set by the welding system and the stored welding parameters, until all welds are completed. In step S 300 The specific steps for extracting the smallest weld node include: The welding system analyzes and identifies the geometric features of the 3D model to determine the welding area and the boundaries of each welding node; Based on the shape of the 3D model and the welding rules, the welding system divides the welding area into multiple smaller nodes; The welding system uses an automated algorithm to extract the smallest welding node from the entire welding area and assigns corresponding welding parameters to the smallest welding node. In step S 300 The specific steps for automatically allocating weld interruptions include: The extra-long, non-welded parts of the hoisting components in the 3D model are pre-cut to achieve standardized specifications. Analyze and calculate the welding line position at the connection between the angle steel and the circular arc base plate; According to the fixed placement rules of angle steel, determine the starting reference point of angle steel, and the welds on both sides of angle steel are arranged alternately; When intersecting with the angle steel weld, the staggered welding rule is continued to generate the reference discontinuity rule and displayed on the three-dimensional model; Observe whether the baseline discontinuity rule is reasonable. If there is no problem, after extracting the smallest welding node, perform global allocation according to the baseline discontinuity rule.

2. The welding method for the steel liner of the nuclear island containment vessel according to claim 1, characterized in that, In step S 100 Among them, the assembly gap between the circumferential back rib angle steel, the vertical back rib angle steel and the wall panel is controlled within a first preset distance range, the first preset distance being 0mm to +1mm.

3. The welding method for the steel liner of the nuclear island containment vessel according to claim 1, characterized in that, In step S 100 The welding parameters for the vertical back rib angle steel are set as follows: The first welding current is 140A~155A, the first welding voltage is 21-26V, the first welding speed is 2.4mm / s~2.6mm / s, the first oscillation amplitude is 1.5-2.5mm, and the first oscillation speed is 10mm~30mm / s; The welding parameters for the circumferential back rib angle steel are set as follows: The second welding current is 168A to 185A, the second welding voltage is 21-26V, the second welding speed is 2.9mm / s to 3.1mm / s, the second oscillation amplitude is 1.5-2.5mm, and the second oscillation speed is 10mm to 30mm / s.

4. The welding method for the steel liner of the nuclear island containment vessel according to claim 1, characterized in that, The parameter settings for the semi-automatic flux-cored wire gas shielded welding are as follows: The welding wire used is φ1.2mm E501T-1, the shielding gas is ≥99.9% CO2, the spot welding current is 195-205A, the spot welding voltage range is 26.5-27.6V, and the gas flow rate is 16-25L / min.

5. The welding method for the steel liner of the nuclear island containment vessel according to claim 1, characterized in that, In step S 200 Among them, the method for accurately positioning the steel-lined cylinder wall using the robot's end effector TCP include: Step S 210 : Obtain the spatial coordinates [x] of the reference point of the circumferential angle steel i ,y i ,z i ]; Step S 220 The position coordinates of the robot end effector TCP in the robot coordinate system are obtained by using the transformation matrix [R(δ),T(δ)] between the robot coordinate system and the robot tool coordinate system. Step S 230 : The spatial coordinates of the reference point of the circumferential angle steel [x i ,y i ,z i The theoretical reference point is assigned to the 3D model of the circumferential angle steel to unify the spatial position of the 3D model and the physical circumferential angle steel.

6. A welding system for a steel liner of a nuclear island containment vessel, employing the welding method for a steel liner of a nuclear island containment vessel as described in any one of claims 1-5, characterized in that, The welding system includes two symmetrically distributed nine-axis cantilever welding robots, a laser vision camera, flexible tooling, a welding power source arranged on a ground rail platform, a wire feeding system installed on the nine-axis cantilever welding robots, and a torch cleaning station. Each of the nine-axis cantilever welding robots includes a cantilever that is slidably mounted on the ground rail at the bottom and a six-axis welding robot, wherein the six-axis welding robot is hung upside down on the cantilever. The flexible fixture is made of steel pipes of different lengths and fasteners connected together, and the curved surface of the steel lining to be welded is placed on the flexible fixture. The laser vision camera is mounted on the welding torch of the six-axis welding robot; The laser vision camera, the welding power source, the wire feeding system, and the cleaning station are all electrically connected to the nine-axis cantilever welding robot.

7. A readable storage medium, characterized in that, The readable storage medium stores a computer program that, when executed by a processor, implements the steps of the welding method for the steel liner of the nuclear island containment vessel as described in any one of claims 1 to 5.

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