Welding method and system for nuclear island containment steel lining and readable storage medium

Abstract

The invention discloses a nuclear island containment steel lining welding method and system and a storage medium, and relates to the technical field of nuclear power facility welding, and the nuclear island containment steel lining welding method comprises the steps that wall plates and annular vertical back rib angle steel are subjected to assembly spot welding; importing the three-dimensional model into a welding system, reading the structure, size and spatial position information of the model, and setting a theoretical reference point; the steel lining cylinder wall is accurately positioned through a robot tail end TCP; the welding system automatically distributes a welding seam interruption rule, extracts a minimum welding node and issues a welding track to the robot control system; nodes are divided for the steel lining cylinder wall in a welding system, and a scanning sequence and annular vertical back rib angle steel welding parameters are set for each node; the robot carries out welding gun track planning according to the set welding sequence and parameters; and the robot carries out arc-starting welding according to the welding sequence set by the welding system and the stored welding parameters. The welding method solves the technical problems that manual welding of the steel lining is low in efficiency and mistaken and missed welding, and traditional robot welding is low in programming efficiency and complex in operation.

Description

Technical Field

[0001] The present invention relates to the technical field of welding technology for nuclear power plant facilities, and particularly to a welding method, system and readable storage medium for the steel lining of a nuclear island containment Background Art

[0002] The steel lining of the containment is a steel lining plate with a certain thickness attached to the inner surface of the containment. The steel lining of the containment belongs to nuclear safety equipment with a quality assurance level of QA1 and a safety level of II, and its welds are all full penetration butt main welds; the steel lining is mainly composed of four parts: a bottom plate, a haunch area, a cylindrical wall and a dome. Among them, the dome is the capping part of the steel lining of the reactor building containment (as Figure 1 shown), and its outer shape is a spherical hyperbolic shell.

[0003] Chinese Patent No. CN115430940A discloses a welding method, system and readable storage medium for the steel lining of a nuclear island containment. The welding method for the steel lining of the nuclear island containment includes the following steps: controlling a mobile groove processing machine to process the groove of the steel lining plate to ensure the straightness of the groove, controlling the groove angle of the laser to be within a first preset angle range, and controlling the alignment gap of the laser groove to be within a first preset distance range; setting a first preset current, a first preset welding speed and a first swing parameter; performing laser tracking function butt joint calibration; using a ceramic plate as a backing plate and a mixed gas of argon and carbon dioxide as a shielding gas for welding; after welding is completed, performing non-destructive testing to verify the weld quality. The welding method for the steel lining of the nuclear island containment improves the on-site steel lining welding efficiency, reduces welding deformation and welding defects, and improves the on-site welding qualification rate; reduces welding fume and improves the working environment of welders, and has the advantages of good weld quality and high welding efficiency.

[0004] However, the above traditional robot welding method is teaching programming welding. The position of each key point of the teaching playback robot is determined by the operator's naked eye, and programming needs to be carried out for each weld. For such non-standard large curved surface segmented welded structural parts, it takes a long time. Each unit module needs to be programmed (about 500 segmented welds), and the programming workload is huge, which cannot meet the production beat requirements, and has high requirements for the quality of operators.

[0005] Secondly, the offline programming robot can be programmed offline, but it is difficult to adapt to the changes in the fixture and the welding deformation of the workpiece. Especially for such thin-walled welded structures, there may be large deformations during the welding process, and the welding trajectory of the robot needs to be adjusted in real time, which does not meet the actual application requirements.

[0006] Finally, for the large number of segmented fillet welds of such large thin-walled curved surface segmented structures, there are problems such as low traditional welding efficiency, easy miswelding and missed welding; the traditional robot welding teaching programming has low efficiency and complex operation, and is not applicable. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to address the problems and deficiencies existing in the prior art, and provide 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 manual welding efficiency, easy miswelding, missed welding of the back rib unit module of the steel lining, and low programming efficiency and complex operation of traditional robotic welding technology.

[0008] To solve the above problems, the present invention adopts the following technical solutions: The first object of the present invention is to provide a welding method for the steel lining of the nuclear island containment vessel. The welding method for the steel lining of the nuclear island containment vessel includes the following steps: Step S 100 : Physical assembly of the steel lining cylinder wall unit; Assemble the wall plate with the circumferential back rib angle steel and the vertical back rib angle steel, and fix them by semi-automatic flux-cored wire gas shielded spot welding. Step S 200 : Import of the 3D model; Import the 3D model of the containment vessel steel lining into the intelligent welding system. The intelligent welding system reads the structure, dimensions, and spatial relative position information of the 3D model of the containment vessel steel lining, and sets the theoretical reference points of the containment vessel steel lining. Step S 300 : Precise positioning of the steel lining cylinder wall by the TCP of the robot end; The welding system automatically distributes the weld intermittent rules and extracts the minimum welding nodes, and sends the automatically generated welding trajectory and parameters to the robot control system. Step S 400 : Model processing and parameter setting Divide the imported steel lining cylinder wall into nodes in the welding system. Each node is a small steel lining back rib surrounding surface unit, and set the scanning order, circumferential back rib angle steel welding parameters, and vertical back rib angle steel welding parameters for each steel lining back rib surrounding surface 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 : Automatic welding by the robot; The robot starts arc welding formally 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 and the vertical back rib angle steel and the wall panel is controlled within the range of a first preset distance, and the first preset distance is 0 mm to +1 mm.

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

[0011] Preferably, in step S 200 Among them, the steps of accurately positioning the steel lining cylinder wall through the TCP at the end of the robot include: Determine the position where the BP0 detection is relatively stable on the display screen, and adjust the up, down, left, and right keys of the remote control to make the weld seam at the center position of the image window, and the laser line is about 5 mm to 10 mm to the left of the vertical "cross" line in the image window; Fix the welding torch above the center of the weld seam and set it higher than the surface plane of the steel lining cylinder wall; Make a marking point under the laser and conduct data acquisition; After collecting the preset number of marking points, turn off the calibration function.

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

[0013] Preferably, in step S 200 Among them, the method of accurately positioning the steel lining cylinder wall through the TCP at the end of the robot includes: Step S 210 : Obtain the spatial coordinates [x i , y i , z i of the circumferential angle steel reference point; Step S 220: Obtain the position coordinates of the TCP at the end of the robot in the robot coordinate system through the transformation matrix [R(δ), T(δ)] between the robot coordinate system and the robot tool coordinate system; Step S 230 : Assign the spatial coordinates [x i , y i , z i of the circumferential angle steel reference point to the theoretical reference point in the circumferential angle steel three-dimensional model, so as to unify the spatial positions of the circumferential angle steel three-dimensional model and the circumferential angle steel physical object.

[0014] Preferably, in step S 300 , the specific steps of extracting the minimum welding node include: The welding system analyzes and identifies the geometric features of the three-dimensional model, determines the welding area and the boundaries of each welding node; According to the shape of the three-dimensional model and the welding rules, the welding system divides the welding area into multiple smaller nodes; The welding system extracts the minimum welding node from the entire welding area through an automated algorithm and assigns corresponding welding parameters to the minimum welding node.

[0015] Preferably, in step S 300 , the specific steps of automatically allocating weld breaks include: Perform cutting pretreatment on the extra-long non-welded part of the hoisting member in the three-dimensional model to complete the specification unification; Analyze and calculate the welding line position at the connection part of the angle steel and the circular arc bottom plate; According to the fixed placement rules of the angle steel, determine the starting reference point of the angle steel, and the welds on both sides of the angle steel are staggered; When intersecting with the angle steel weld, continue the staggered welding rule, generate the reference break rule, and display it on the three-dimensional model; Observe whether the reference break rule is reasonable. If there is no problem, after extracting the minimum welding node, perform global allocation according to the reference break rule.

[0016] The second object of the present invention is to provide a welding system for the steel lining of the nuclear island containment. Using the above-mentioned welding method for the steel lining of the nuclear island containment, the welding system includes two sets of symmetrically distributed nine-axis cantilever welding robots, laser vision cameras, flexible tooling, welding power supplies arranged on the ground rail platform, wire feeding systems and gun cleaning stations installed on the nine-axis cantilever welding robots; Each set of the nine-axis cantilever welding robots includes a cantilever slidably installed at the bottom on the ground rail and a six-axis welding robot, and the six-axis welding robot is hung upside down on the cantilever; The flexible tooling is connected by steel pipes and fasteners of different lengths, and the steel lining curved surface segments to be welded are placed on the flexible tooling; The laser vision camera is installed on the welding torch of the six-axis welding robot; The laser vision camera, the welding power source, the wire feeding system and the gun cleaning station are all electrically connected to the nine-axis cantilever welding robot.

[0017] The third object of the present invention is to provide a readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the welding method of the steel lining of the nuclear island containment vessel as described above are realized.

[0018] Compared with the prior art, the present invention has significant advantages and beneficial effects, which are specifically reflected in the following aspects: 1. The welding method of the steel lining of the nuclear island containment vessel in this application includes the steps of: 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 spot welding; importing the three-dimensional model of the steel lining of the containment vessel into the welding system, and the welding system reads the structure, size and spatial relative position information of the steel lining of the containment vessel, and sets the theoretical reference points of the steel lining of the containment vessel; precisely positioning the steel lining cylinder wall through the TCP at the end of the robot to complete the assembly of the steel lining cylinder wall units, where each steel lining cylinder wall unit module is composed of a wall panel, a circumferential back rib angle steel and a vertical back rib angle steel; dividing nodes for the imported steel lining cylinder wall units in the welding system, each node is a small steel lining back rib surrounding surface unit, and setting the scanning sequence, the welding parameters of the circumferential back rib angle steel and the welding parameters of the vertical back rib angle steel for each steel lining back rib surrounding surface unit; performing laser tracking function butt joint calibration; the intelligent welding system automatically generates the scanning and welding trajectories and sends them to the robot body, and the robot body will plan the welding torch trajectory according to the set welding sequence and parameters. Before reaching the node welding, the laser vision camera will accurately find the position of the initial point to be welded and perform welding according to the initial task.

[0019] 2. There is no need for teaching programming, and the initial welding seam is accurately found through the way of model import + laser vision to realize automatic programming of the robot.

[0020] 3. It has strong adaptability and is suitable for welding of multi-variety large curved surface multi-section back rib structures, breaking through the functions that cannot be realized by traditional teaching robots and offline programming robots; 4. Improve the welding efficiency, automatically plan the welding torch posture and trajectory, scan and weld at the same time, and improve the welding efficiency and quality. Description of the Drawings

[0021] Figure 1 It is a schematic flow chart of the welding method of the steel lining of the nuclear island containment vessel in the embodiment of the present invention; Figure 2 It is a front view schematic diagram of the steel lining structure of the containment vessel in the embodiment of the present invention; Figure 3 Schematic diagram of the typical structure of the steel lining unit module without penetrations in the embodiments of the present invention; Figure 4 Schematic diagram of the typical structure of the steel lining unit module with penetrations in the embodiments of the present invention; Figure 5 Schematic diagram of the welding system structure of the steel lining of the nuclear island containment in the embodiments of the present invention; Figure 6 Schematic diagram of the node distribution structure of the steel lining cylinder wall unit module in the embodiments of the present invention; Figure 7 Schematic diagram of the setting of a single node in the embodiments of the present invention; Figure 8 Schematic diagram of the structure of the steel lining E03 unit module in the embodiments of the present invention; Figure 9 Schematic diagram of the P-point positioning of the 3D model of the steel lining E03 unit module in the embodiments of the present invention; Figure 10 Schematic diagram of the node division in the embodiments of the present invention; Figure 11 Schematic diagram of the welding sequence of the steel lining cylinder wall in the embodiments of the present invention; Figure 12 Schematic diagram of the requirements for the arrangement of staggered fillet welds in the embodiments of the present invention.

[0022] Description of reference numerals: 1 - Containment steel lining; 10 - Steel lining 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 - Gun cleaning station; Detailed implementation manners To make the above objects, features, and advantages of the present invention more apparent and understandable, the following detailed description of the specific embodiments of the present invention is provided with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary and are not intended to limit the scope of the present application. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present application. However, obviously, one or more embodiments can be implemented without these specific details. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present application. The terms used herein are for describing specific embodiments only and are not intended to limit the present application. The terms "including", "comprising", etc. used herein indicate the presence of the described 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 should be interpreted to have a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0023] Some block diagrams and / or flowcharts are shown in the drawings. It should be understood that some of the 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 the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing devices, so that when executed by the processor, these instructions can create a device for implementing the functions / operations illustrated in these block diagrams and / or flowcharts.

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

[0025] Due to the relatively complex distribution of welds on the steel lining unit module and the high requirements for welding deformation, the overall deformation of the containment steel lining components shall not exceed ±20 mm / 1 m, and strict control requirements are imposed on the weld dimensions (the length tolerance does not exceed 20 mm, and the fillet weld size does not exceed 2 mm).

[0026] In addition, the connection between the back rib and the wall plate on the curved surface is welded by means of staggered fillet welds, and the fillet weld size is 6 mm. Among them, the length of the circumferential large angle steel staggered weld is 380 mm, and the length of the vertical small angle steel staggered weld is 400 mm.

[0027] In the prior art, the welding of the back rib angle steel welds of the steel lining is carried out by semi-automatic gas shielded welding with flux-cored wire, with relatively low welding efficiency and high labor intensity for welders. During the peak period, about 10 welders are simultaneously involved. In addition, due to the uneven skill levels of welders, the weld quality fluctuates greatly, and generally, grinding is required after welding to meet the requirements. More importantly, situations such as missed welding and wrong welding are likely to occur.

[0028] On the other hand, the traditional robot welding method is teaching programming welding. The position of each key point of the teaching and playback robot is determined by the operator with the naked eye, and programming needs to be carried out for each weld seam. For this kind of non-standard large curved surface segmented welding structural parts, it takes a long time. Each unit module needs to be programmed (about 500 segmented weld seams), the programming workload is huge, it cannot meet the production beat requirements, and the quality requirements for operators are relatively high.

[0029] Although the offline programming robot can be programmed offline, it is difficult to adapt to the changes of the tooling and the welding deformation of the workpiece. Especially for this kind of thin-walled welding structure, there may be large programming deformation during the welding process, and the welding trajectory of the robot needs to be adjusted in real time, which does not meet the actual application requirements.

[0030] For the welding of a large number of segmented fillet welds of such large thin-walled curved surface segments as the steel lining unit module, regarding the technical problems of low efficiency, easy wrong welding and missed welding in traditional manual welding, and low efficiency, complex operation and inapplicability in traditional robot welding teaching programming, please refer to Figures 1-12 As shown, the embodiment of the present invention provides a welding method for the steel lining of a nuclear island containment vessel. The welding method for the steel lining of the nuclear island containment vessel includes the steps: Step S 100 : Physical assembly of the steel lining cylinder wall unit 10; Assemble the wall plate 11 with the circumferential back rib angle steel 12 and the vertical back rib angle steel 13, and fix them by semi-automatic flux-cored wire gas shielded spot welding.

[0031] In this step, through pre-spot welding, the relative position between the wall plate 11 and the back rib angle steel can be ensured to be accurate, laying a foundation for subsequent high-quality welding, effectively avoiding welding defects caused by inaccurate assembly and positioning, such as weld misalignment, improper gap, etc., thereby improving the quality of the welded joint and the accuracy of the overall structure.

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

[0033] After importing the 3D model into the welding system, the user can manually or automatically select three reference points through a vision camera to calibrate the spatial position of the steel lining. These reference points are usually feature points with fixed positions and calibration meanings on the surface of the steel lining, which can help the welding system determine the precise position of the steel lining in the actual space.

[0034] Step S 200 : Precise positioning of the steel lining cylinder wall through the TCP at the end of the robot; It should be noted that the TCP (Tool Center Point) at the end of the robot refers to a point on the end effector (tool) of the robot. This point is the basis for the robot's motion control and path planning. When no tool is installed at the end of the robot, the TCP point is the end of the robot body, that is, the center point of the sixth-axis flange. When a tool (such as a welding torch of a welding robot, a spray gun of a spraying robot, etc.) is installed at the end of the robot, the TCP point moves to the end of the tool and becomes the origin of the tool 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 interruption 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, through precise positioning, the welding process is more precise and controllable. The robot can weld strictly according to the preset trajectory and parameters, avoiding errors caused by manual operation, ensuring the forming quality of the weld, including parameters such as the width, height, and penetration depth of the weld are more uniform, improving the performance and reliability of the welded joint, and thus enhancing the welding quality of the entire steel lining structure of the nuclear island containment.

[0037] Step S 400 : Model processing and parameter setting Divide nodes for the imported steel lining cylinder wall in the intelligent welding system. Each node is a small steel lining back rib circumferential surface unit, and set the scanning order, as well as the welding parameters of the circumferential back rib angle steel 12 and the vertical back rib angle steel 13 for each steel lining back rib circumferential surface unit.

[0038] In this step, the robot has clearly defined the welding sequence and corresponding parameters of each node before welding, reducing the time waste caused by parameter adjustment and welding sequence decision-making during the welding process, further improving the welding efficiency, and realizing the high-efficiency automated production of the welding process.

[0039] Step S 500:The robot plans the torch trajectory according to the set welding sequence and parameters. Before reaching the node welding, the laser vision camera accurately locates the position of the initial point to be welded. Step S 600 :The robot performs automatic welding. The robot starts arc welding officially according to the welding sequence set by the welding system and the stored welding parameters until all welds are completed.

[0040] Thus, in the whole welding method, from the import of the 3D model, node division and parameter setting, welding trajectory planning to automatic welding, most links are automatically completed by the intelligent welding system and the robot, reducing the factor of human intervention. The reduction of human intervention reduces the risks of welding quality problems and safety accidents caused by human operation errors or non-standard operations, improves the reliability and safety of the welding process, which is crucial for the nuclear island containment structure with extremely high safety requirements. Compared with the traditional manual welding method, it greatly shortens the welding time, improves the welding efficiency, can complete more welding tasks in the same time, and is conducive to accelerating the construction progress of the steel lining of the nuclear island containment.

[0041] In the embodiment of the present invention, please refer to Figure 2 As shown, the diameter of the steel lining of the nuclear island containment is selected to be 42.8 meters. The cylindrical wall of the steel lining is divided into 9 sections in total. Sections 1-9 are all composed of 10 steel lining unit modules. Each steel lining unit module is welded by a 6mm / Q265HR steel plate, longitudinal back rib angle steel, transverse back rib angle steel and φ8mm*80mm anchor nails. The steel lining unit module is a typical thin-walled curved surface structure. The transverse and vertical angle steel back ribs distributed on it divide the whole curved surface into multiple closed or semi-closed segmented structures. The materials of the longitudinal and transverse back rib angle steels are Q235B. The specification of the longitudinal back rib angle steel is L75*50*8mm, and the transverse back rib angle steel is 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 plate 11 is controlled within the range of the first preset distance, and the first preset distance is 0mm to +1mm.

[0043] Since a suitable assembly gap helps to avoid the generation of welding defects. When the gap is too small, it may cause insufficient filler metal in the weld, resulting in defects such as incomplete penetration; while when the gap is too large, it may cause excessive filler metal in the weld, resulting in defects such as 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 to be moderate, reducing the generation of welding defects and improving the quality of the welded joint.

[0044] In the steel lining of the nuclear island containment, the stability of the structure is the key to ensuring safe operation. By controlling the gap within the preset range, welding stress and deformation can be reduced, the accuracy and stability of the structure can be improved, thereby enhancing the safety of the entire structure.

[0045] Specifically, in step S 100 Among them, the welding parameters of 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 swing amplitude is 1.5 - 2.5mm, and the first swing speed is 10mm - 30mm / s; The welding parameters of the circumferential back rib angle steel 12 are set as follows: The second welding current is 168A - 185A, the second welding voltage is 21 - 26V, the second welding speed is 2.9mm / s - 3.1mm / s, the second swing amplitude is 1.5 - 2.5mm, and the second swing speed is 10mm - 30mm / s.

[0046] Thus, by setting specific parameters such as welding current, voltage, speed, swing amplitude, and swing 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 - 155A can ensure the penetration depth and forming quality of the weld; setting the welding voltage within the range of 21 - 26V can ensure that the width and height of the weld are appropriate; setting the welding speed within the range of 2.4mm / s - 2.6mm / s can avoid the occurrence of 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, setting the welding current of the circumferential back rib angle steel 12 within the range of 168A - 185A, which is slightly higher than that of the vertical back rib angle steel 13, can better meet the welding requirements of the circumferential back rib angle steel 12 and improve the strength and toughness of the weld; setting the welding speed within the range of 2.9mm / s - 3.1mm / s, which is slightly faster than that of the vertical back rib angle steel 13, can improve welding efficiency while ensuring welding quality.

[0048] Specifically, in step S 200 Among them, the steps of precisely positioning the steel lining cylinder wall through the TCP at the end of the robot include: Determine the position where the BP0 detection is relatively stable on the display screen, and adjust the up, down, left, and right keys of the remote control to make the weld seam at the center position of the image window, and the laser line is about 5mm - 10mm to the left of the vertical "cross" line in the image window; Fix the welding torch above the center of the weld seam and set it higher than the surface plane of the steel lining cylinder wall; Make marking points under the laser and conduct data acquisition; After collecting the preset number of marking 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 position deviation during the hoisting process, precise positioning needs to be carried out through the TCP at the end of the robot. The positioning basis can refer to the three spatial position points of the circumferential large angle steel.

[0050] Specifically, the parameters of the semi-automatic flux-cored wire gas shielded welding are set as follows: The welding wire uses φ1.2mm E501T-1. E501T-1 is a rutile type CO2 gas shielded flux-cored wire with excellent welding process performance, soft and stable arc, less spatter, easy slag removal, and beautiful weld formation. It is suitable for flat welding and horizontal welding, can be welded in all positions, and has high welding efficiency.

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

[0052] The spot welding current is 195 - 205A, and the spot welding voltage range is 26.5 - 27.6V, which can provide appropriate heat input to melt the welding wire and fill it into the weld seam to form a good weld formation. Excessive current may cause the weld to overheat, resulting in defects such as burn-through and undercut; too small current may cause insufficient weld filling, resulting in defects such as incomplete penetration and porosity; an appropriate spot welding voltage can maintain a stable arc, reduce the fluctuation and interruption of the arc, and improve the stability and reliability of the welding process.

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

[0054] Specifically, please refer to Figure 6 、 7 、8, 9 as shown, in step S 200 Among them, the method for precisely positioning the steel lining cylinder wall through the TCP at the end of the robot includes: Step S 210 : Obtain the spatial coordinates [x i , y i , z i of the circumferential angle steel reference point.

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

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

[0057] In this step, the transformation matrix is used to realize the dynamic mapping between the robot coordinate system and the tool coordinate system, ensuring the accurate expression of the position of the end TCP in the global coordinate system and reducing the cumulative error caused by coordinate deviation.

[0058] Step S 230 : Assign the spatial coordinates [x i , y i , z i of the circumferential angle steel reference points to the theoretical reference points in the three-dimensional model of the circumferential angle steel, realizing the unity of the spatial positions of the three-dimensional model of the circumferential angle steel and the physical circumferential angle steel.

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

[0060] Thus, through data-driven positioning and model-physical entity fusion, the accuracy, efficiency, and reliability of the installation of the steel lining cylinder wall are significantly improved, and at the same time, an extensible technical framework is provided for intelligent construction. In the future, it is necessary to further optimize the robustness of the sensors and enhance the model adaptability to meet more complex engineering requirements.

[0061] Specifically, in step S 300 , the specific steps for extracting the minimum welding nodes are as follows: Step 1: The welding system analyzes and identifies the geometric features of the three-dimensional model, determines the welding areas and the boundaries of each welding node; In this step, first, the geometric shape of the steel lining is analyzed to determine which areas are the welding areas that need to be key-controlled. By identifying welding joints, angle changes, weld types, etc., the boundaries of each welding node are determined. By identifying and marking the welding joints, angle changes, possible weld paths, and other geometric features in the steel lining that affect the welding process, the following aspects are mainly involved: a. Angle change detection: By calculating the change in the surface normal of the steel lining, the joints and welding areas are identified.

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

[0063] c. Weld path recognition: By identifying the connecting lines between welding areas, determine the starting and ending points of the weld.

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

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

[0066] Specifically, the welding system determines how to divide the smallest welding nodes by the "enclosing" method, mainly divided into the following types: a. Applicable situation of being enclosed on four sides: Applicable to those regular and closed welding areas, such as large flat areas, or areas surrounded by objects or existing welds on four sides.

[0067] Implementation method: By searching for all boundary lines intersecting the welding area, the system identifies a complete enclosed area, and the four boundaries of this area are completely surrounded by objects or existing welds.

[0068] Implementation algorithm: Use the Convex Hull algorithm or polygon splitting algorithm to detect and confirm the enclosed area.

[0069] b. Applicable situation of being enclosed on three sides: Applicable to some areas enclosed by only three boundaries, such as seams between connecting components, or areas with one side open.

[0070] Implementation method: The system detects the boundaries of the welding area and identifies those areas enclosed by only three sides. These areas are usually located at the joints of workpieces or there are gaps between two parts.

[0071] Implementation algorithm: The connected component analysis algorithm in graph theory can be used to identify which areas are connected to the external area and ensure that only the areas enclosed on three sides are extracted.

[0072] c. Applicable situation of being enclosed on two sides: Applicable to workpieces with complex geometric shapes, such as areas where two boundaries are restricted by other components and the other two sides are open.

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

[0074] Implementation algorithm: Use the space segmentation algorithm or the scan line algorithm based on geometric shapes to analyze the shape of the workpiece and identify the areas enclosed on two sides.

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

[0076] Thereby, for each smallest welding node, the welding system automatically generates a welding path according to its geometric characteristics, heat input control requirements, and welding sequence. The welding path will be as short as possible and avoid excessive repeated operations; the welding trajectory will be optimized within each welding node to ensure that the robot welds along the optimal path, thereby improving the welding efficiency and reducing the movement time of the robot.

[0077] It should be explained that extracting the smallest welding nodes means that the welding system automatically extracts the smallest welding nodes from the overall welding area according to the geometric shape and welding requirements of the welded workpiece. These nodes are the basic areas for precise control and operation during the welding process and are usually composed of one or more weld seams.

[0078] Specifically, in step S 300 Among them, the specific steps for automatically assigning the weld discontinuity rules include: Step 1: Preprocess the ultra-long non-welded parts of the hoisting components in the 3D model by cutting to complete the specification unification.

[0079] In this step, first, the model is processed, and the ultra-long non-welded parts of the small angle steel (used for component hoisting) are preprocessed (cut) to complete the specification unification with other small angle steels to avoid affecting the weld distribution rules.

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

[0081] Step 3: Determine the starting reference point of the angle steel according to the fixed placement rule of the angle steel, and the welds on both sides of the angle steel are staggered.

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

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

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

[0085] Accordingly, the welding system automatically assigns weld seams to each area to be welded in the model according to welding rules and the geometric data of the steel lining. The length, shape, type, welding direction, etc. of each weld seam segment are intelligently assigned by the system according to structural and technological requirements.

[0086] Please refer to Figure 5 As shown, an embodiment of the present invention also provides a welding system for the steel lining of a nuclear island containment. Using the above-mentioned welding method for the steel lining of a nuclear island containment, the welding system includes two sets of symmetrically distributed nine-axis cantilever welding robots 100, laser vision cameras 200, flexible tooling 300, a welding power source 400 arranged on a ground rail platform, a wire feeding system and a gun cleaning station 500 installed on the nine-axis cantilever welding robot 100; Each set of the nine-axis cantilever welding robots 100 includes a cantilever 110 slidably installed at the bottom on the ground rail 600 and a six-axis welding robot 120, and the six-axis welding robot 120 is hung upside down on the cantilever 110; The flexible tooling 300 is connected by steel pipes and fasteners of different lengths, and the curved surface segments of the steel lining to be welded are placed on the flexible tooling 300; The laser vision camera 200 is installed on the welding torch of the six-axis welding robot 120; The laser vision camera 200, the welding power source 400, the wire feeding system and the gun 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 is composed of two sets of symmetrically distributed nine-axis cantilever welding robots 100, laser vision cameras 200, flexible tooling 300, a welding power source 400 arranged on the ground rail 600 platform, a wire feeding system and a gun cleaning station 500 installed on the nine-axis cantilever welding robot 100. Each set of nine-axis cantilever welding robots 100 specifically includes 1 six-axis welding robot 120, and the other three axes include a cantilever X-axis, a laterally moving Y-axis, and a ground rail 600 moving along the X-axis. The six-axis welding robot 120 is hung upside down on the cantilever 110, the welding power source 400 is arranged on the platform on the ground rail 600, and the platform can move along with the ground rail. The gun cleaning station 500 is arranged on the column; the curved surface segments of the steel lining to be welded are placed on the flexible tooling 300, and the flexible tooling 300 is connected by steel pipes and fasteners of different lengths. Curved surfaces of different diameters can be assembled by flexible tooling with different length distributions.

[0088] Considering the reason of welding efficiency, the entire welding system can store two curved surface segments of the steel lining (double-station distribution) in the length direction at the same time to realize the collaborative operation of robots and manual workers.

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

[0090] Next, combining the steel lining 3D model and real-time weld detection data, the welding system can automatically generate the optimal welding trajectory. The welding system uses intelligent algorithms to perform path planning, optimize welding paths and welding angles to adapt to different workpiece shapes and weld positions.

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

[0092] Therefore, through this welding system, the factory can achieve efficient, accurate and automated welding operations, reduce manual intervention, and improve welding quality and production efficiency. At the same time, the welding system also has strong adaptability and can be flexibly adjusted according to different workpieces and welding requirements to meet the needs of various production scenarios.

[0093] In addition, to achieve the above-mentioned purpose, an embodiment of the present invention further provides a readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the welding method for the nuclear island containment steel lining as described in any of the above items are implemented.

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

[0095] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A welding method for the steel lining of a nuclear island containment vessel, characterized in that, The welding method of the steel lining of the nuclear island containment vessel includes the following steps: Step S 100 : Physical assembly of steel-lined cylinder wall units; Assemble the wall panels with the circumferential back rib angle steel and the vertical back rib angle steel, and fix them by semi-automatic flux-cored wire gas shielded spot welding; Step S 200 : Import of 3D model; Import the 3D model of the containment vessel steel lining into the welding system. The welding system reads the structure, dimensions and spatial relative position information of the 3D model of the containment vessel steel lining, and sets the theoretical reference points of the containment vessel steel lining; Step S 300 :Precisely position the steel lining cylinder wall through the TCP at the end of the robot; The welding system automatically distributes the weld intermittent rules and extracts the minimum welding nodes, and sends the automatically generated welding trajectory and parameters to the robot control system; Step S 400 : Model processing and parameter setting; Divide the nodes of the imported steel lining cylinder wall in the welding system, and set the scanning order, circumferential back rib angle steel welding parameters and vertical back rib angle steel welding parameters for each steel lining back rib surface unit; Step S 500 : The robot plans the torch trajectory according to the set welding sequence and parameters. Before reaching the node welding, the laser vision camera accurately locates the position of the initial point to be welded. Step S 600 : Automatic welding by the robot; The robot starts arc welding formally according to the welding sequence set by the welding system and the stored welding parameters until all welds are completed.

2. The welding method of the steel lining of the nuclear island containment according to claim 1, characterized in that, In step S 100 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, and the first preset distance is 0 mm to +1 mm.

3. The welding method of the steel lining of the nuclear island containment according to claim 1, wherein In step S 100 Among them, the welding parameters of 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 swing amplitude is 1.5 - 2.5mm, and the first swing speed is 10mm - 30mm / s; The welding parameters of the circumferential back rib angle steel are set as follows: The second welding current is 168A - 185A, the second welding voltage is 21 - 26V, the second welding speed is 2.9mm / s - 3.1mm / s, the second swing amplitude is 1.5 - 2.5mm, and the second swing speed is 10mm - 30mm / s.

4. The welding method of the steel lining of the nuclear island containment according to claim 1, characterized in that, In step S 200 Among them, the steps of accurately positioning the steel lining cylinder wall through the TCP at the end of the robot include: Determine the position where the BP0 detection is relatively stable on the display screen, and adjust the up, down, left and right keys of the remote control to make the weld in the center of the image window, and the laser line is 5mm - 10mm to the left of the vertical "cross" line in the image window; Fix the welding torch above the center of the weld and set it higher than the surface plane of the steel lining cylinder wall; Make marking points under the laser and perform data acquisition; After collecting the preset number of marking points, turn off the calibration function.

5. The welding method of the steel lining of the nuclear island containment according to claim 1, characterized in that, The parameters of the semi-automatic flux-cored wire gas shielded welding are set as follows: The welding wire uses E501T-1 with a diameter of φ1.2mm, the shielding gas is CO2 with a purity of ≥99.9%, 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.

6. The welding method of the steel lining of the nuclear island containment according to claim 1, wherein In step S 200 Among them, the method for accurately positioning the steel lining cylinder wall by the TCP at the end of the robot Including: Step S 210 : Obtain the spatial coordinates [x i , y i , z i of the circumferential angle steel reference point; Step S 220 : Obtain the position coordinates of the TCP at the end of the robot in the robot coordinate system through the transformation matrix [R(δ), T(δ)] between the robot coordinate system and the robot tool coordinate system; Step S 230 : Assign the spatial coordinates [x i , y i , z i of the circumferential angle steel reference point to the theoretical reference point in the circumferential angle steel three-dimensional model, so as to unify the spatial positions of the circumferential angle steel three-dimensional model and the circumferential angle steel physical object.

7. The welding method of the steel lining of the nuclear island containment according to claim 1, characterized in that, In step S 300 Among them, the specific steps of extracting the minimum welding node include: The welding system analyzes and identifies the geometric features of the 3D model, determines the welding area and the boundaries of each welding node; According to the shape of the 3D model and the welding rules, the welding system divides the welding area into multiple smaller nodes; The welding system extracts the minimum welding nodes from the entire welding area through an automated algorithm and assigns corresponding welding parameters to the minimum welding nodes.

8. The welding method of the steel lining of the nuclear island containment according to claim 1, characterized in that In step S 300 Among them, the specific steps for automatically allocating weld discontinuities include: Cut and preprocess the ultra-long non-welded part of the lifting member in the 3D model to complete the specification unification; Analyze and calculate the welding line position at the connection part of the angle steel and the circular arc bottom plate; According to the fixed placement rules of the angle steel, determine the starting reference point of the angle steel, and the welds on both sides of the angle steel are staggered; When intersecting with the angle steel weld, continue the staggered welding rule, generate the reference intermittent rule, and display it on the 3D model; Observe whether the reference intermittent rule is reasonable. If there is no problem, after extracting the minimum welding nodes, perform global allocation according to the reference intermittent rule.

9. A welding system for the steel lining of a nuclear island containment vessel, which adopts the welding method for the steel lining of a nuclear island containment vessel according to any one of claims 1-8, characterized in that, The welding system includes two sets of nine-axis cantilever welding robots symmetrically distributed, a laser vision camera, a flexible tooling, a welding power source arranged on a ground rail platform, a wire feeding system and a gun cleaning station installed on the nine-axis cantilever welding robot; Each set of the nine-axis cantilever welding robots includes a cantilever slidably mounted at the bottom on the ground rail and a six-axis welding robot, and the six-axis welding robot is hung upside down on the cantilever; The flexible tooling is connected by steel pipes and fasteners of different lengths, and the steel lining surface segments to be welded are placed on the flexible tooling; The laser vision camera is installed on the welding torch of the six-axis welding robot; The laser vision camera, the welding power source, the wire feeding system and the gun cleaning station are all electrically connected to the nine-axis cantilever welding robot.

10. A readable storage medium, characterized in that, The readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the welding method of the nuclear island containment steel lining as described in any one of claims 1 to 8 are implemented.

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