A robotic welding method for nuclear power plant penetration sleeves

Abstract

This invention provides a robotic welding method for nuclear power plant penetration sleeves, belonging to the field of sleeve welding technology. The method includes the following steps: S1, machining a single-sided V-shaped bevel on the weldment part according to set requirements, and grinding the area to be welded on the penetration sleeve; S2, using assembly fixtures to adjust the weld height and assembly gap of the weldment part relative to the penetration sleeve to a set range; S3, using positioning and fixing fixtures to fix the weldment part onto the penetration sleeve, and providing a backing plate on the back of the weld; S4, installing the penetration sleeve onto a positioner, and adjusting the welding robot's welding torch to a position matching the weld; S5, using the welding robot to weld the weldment onto the penetration sleeve; S6, cleaning the weld and performing non-destructive testing on it. This method not only completes welding efficiently but also ensures reliable quality and a high pass rate, solving problems such as personnel shortages and low efficiency.

Description

Technical Field

[0001] This invention belongs to the field of sleeve welding technology, specifically relating to a robotic welding method for sleeves used in nuclear power plant penetration components. Background Technology

[0002] In nuclear power plant steel structure engineering, the containment steel liner is a Class II nuclear facility. The liner contains various sizes of through-hole sleeves, primarily serving as ventilation, pipeline, equipment, and personnel access points. These through-hole sleeves mainly consist of steel pipes, reinforcing rings, and stiffening ribs. The reinforcing rings are fully penetrated welded to the steel pipes, while the stiffening ribs are welded to the steel pipes using fillet welds. Traditionally, manual shielded metal arc welding (SMAW) is used: the reinforcing rings are welded on both sides, with the reverse side being cleaned and welded after one side is finished; the stiffening ribs are welded directly according to the weld leg height. This traditional process is inefficient, labor-intensive, and requires non-destructive testing and grinding after cleaning, making the process complex and resulting in low overall construction efficiency. This significantly impacts project schedule and cost.

[0003] According to the requirements for steel-lined nuclear secondary equipment, the penetration sleeve must be welded by nuclear-grade welders. In recent years, rising labor costs have led to a shortage of welders and welding operators, especially nuclear-grade welders who are difficult to train and have long training cycles. Currently, with the construction of several new nuclear power projects underway, the shortage of welding personnel will become even more severe. While existing technologies employ robotic welding, the welding results are unsatisfactory and cannot meet the welding requirements for nuclear-grade penetration sleeves. Summary of the Invention

[0004] The purpose of this invention is to solve the problems mentioned in the background art by providing a robotic welding method for nuclear power plant through-hole sleeves, which can not only complete the welding with high efficiency, but also with reliable quality and high pass rate, thus solving the problems of personnel shortage and low efficiency.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A robotic welding method for nuclear power plant penetration sleeves includes the following steps:

[0007] S1. Machin the welded parts with the required single-sided V-shaped bevel, and grind the areas to be welded on the through sleeve and the welded parts.

[0008] S2. Use assembly tooling to adjust the weld height and assembly gap of the welded parts relative to the through sleeve to the set range;

[0009] S3. The welding parts are fixed on the through sleeve by a positioning and fixing fixture, and a backing plate is provided on the back of the weld.

[0010] S4. Install the through sleeve onto the positioner and adjust the welding robot's welding torch to a position that matches the weld seam;

[0011] S5. Use a welding robot to weld the workpiece onto the through sleeve;

[0012] S6. Clean the weld and perform non-destructive testing on it.

[0013] Preferably, the angle of the single-sided V-shaped bevel in step S1 is required to be 40° to 50°, and the blunt edge is required to be 0 to 2 mm; the through sleeve is made of carbon steel with a wall thickness of 16 to 40 mm.

[0014] Preferably, the pad in step S3 is made of ceramic material; the pad is an annular shape that matches the through sleeve; the pad has a groove at the weld.

[0015] Preferably, the assembly tooling in step S2 is a spiral adjustment and positioning device; the positioning and fixing tooling in step S3 is a number of angle irons.

[0016] Preferably, step S5 specifically includes the following sub-steps:

[0017] S51. Write the welding operation program for the welding robot and simulate the operation of the welding program;

[0018] S52. Clean the weld and check the equipment condition; the equipment condition includes the current of the welding power source and the flow rate of the welding shielding gas.

[0019] S53. Select the welding program parameters that match the position of the through sleeve, and run the welding program according to the parameters to perform welding.

[0020] S54. The welding robot is reset, and the through sleeve is removed from the positioner.

[0021] Preferably, the welding shielding gas in step S52 comprises 82% Ar and 12% CO2, and the flow rate of the welding shielding gas is 15-25 L / min.

[0022] Preferably, the welding procedure parameters in step S53 include flat welding parameters and horizontal welding parameters; the welding in step S53 includes sequential root pass welding, fill pass welding and cover pass welding.

[0023] Preferably, the flat welding parameters include:

[0024] During the root pass welding, the welding current is 200A~280A, the welding voltage is 20~30V, the welding speed is 20cm / min~25cm / min, the welding torch oscillation amplitude is 1mm~3mm, the welding torch oscillation frequency is 1~2Hz, and the welding torch dwell time at both ends of the oscillation amplitude is 0.1s~0.3s. When the arc is closed, the post-processing current is 150A and the post-processing time is 2s.

[0025] During filler welding, the welding current is 180A~250A, the welding voltage is 18~28V, the welding speed is 20cm / min~30cm / min, the welding torch oscillation amplitude is 2mm~6mm, the welding torch oscillation frequency is 1~2Hz, the welding torch dwell time at both ends of the oscillation amplitude is 0.1s~0.3s, the post-processing current is 150A when the arc is closed, and the post-processing time is 2s when the arc is closed.

[0026] During cover welding, the welding current is 200A~260A, the welding voltage is 20~28V, the welding speed of the welding torch is 20cm / min~35cm / min, the welding torch oscillation amplitude is 2mm~7mm, the welding torch oscillation frequency is 1~2Hz, the welding torch stays at both ends of the oscillation amplitude for 0.1s~0.3s, the post-processing current is 150A when the arc is closed, and the post-processing time is 2s when the arc is closed.

[0027] Preferably, the horizontal welding parameters include:

[0028] During the root pass welding, the welding current is 200A~280A, the welding voltage is 20~30V, the welding speed is 20cm / min~25cm / min, the welding torch oscillation amplitude is 1mm~3mm, the welding torch oscillation frequency is 1~2Hz, and the welding torch dwell time at both ends of the oscillation amplitude is 0.1s~0.3s. When the arc is closed, the post-processing current is 150A and the post-processing time is 2s.

[0029] During filler welding, the welding current is 180A~250A, the welding voltage is 18~28V, the welding speed is 20cm / min~30cm / min, the welding torch oscillation amplitude is 1~4mm, the welding torch oscillation frequency is 1~2Hz, the welding torch dwell time at both ends of the oscillation amplitude is 0.1s~0.3s, the post-processing current is 150A when the arc is closed, and the post-processing time is 2s when the arc is closed.

[0030] During cover welding, the welding current is 200A~260A, the welding voltage is 20~28V, the welding speed of the welding torch is 25cm / min~40cm / min, the welding torch oscillation amplitude is 2~5mm, the welding torch oscillation frequency is 1~2Hz, the welding torch stays at both ends of the oscillation amplitude for 0.1s~0.3s, the post-processing current is 150A when the arc is closed, and the post-processing time is 2s when the arc is closed.

[0031] Preferably, the gap setting range in step S2 is 4 to 6 mm.

[0032] The beneficial effects of this invention are:

[0033] 1. The flat welding parameters and horizontal welding parameters used in this invention not only have high welding efficiency, but also good welding effect and reliable quality.

[0034] 2. This invention changes the bevel of the through sleeve from K-type to V-type, and uses an annular pad for forced back forming, achieving a single-sided welding and double-sided forming welding effect, eliminating the back root cleaning and grinding process, and improving welding efficiency.

[0035] 3. This invention uses machining for beveling, and employs assembly tooling and positioning fixtures to adjust and fix the welded parts, ensuring that the welding area of ​​the same specification through sleeve is in the same position. This allows multiple workpieces to be welded using the same welding program, saving the time of repeated programming and teaching, and further improving production efficiency.

[0036] 4. This invention replaces manual electrode arc welding with robotic automatic MAG welding for through-hole sleeve welding, which greatly improves welding efficiency and significantly reduces personnel requirements and labor costs.

[0037] 5. The preferred gap between the assembly parts is 4-6mm, which can improve the welding effect and make the weld effectively formed. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the nuclear power plant penetration sleeve and welded parts of the present invention;

[0039] Figure 2 for Figure 1 Schematic diagram of the reverse section of section 1-1;

[0040] Figure 3 for Figure 1 Enlarged view of a portion of point A in the middle;

[0041] Figure 4 This is a partial schematic diagram of the annular pad;

[0042] Figure 5 This is a schematic diagram of the assembly tooling and the positioning and fixing tooling installation;

[0043] Figure 6 This is a schematic diagram of the assembly tooling structure;

[0044] Figure 7 Schematic diagram of the positioning and fixing tooling structure;

[0045] Figure 8 This is a schematic diagram showing the positions of the welding torch and the through-hole sleeve of the present invention;

[0046] Figure 9 This is a schematic diagram of the welding process of the present invention;

[0047] Figure 10a Appearance of a manual shielded metal arc weld before grinding;

[0048] Figure 10b The appearance of a manual shielded metal arc weld after grinding;

[0049] Figure 11a This is a visual representation of the weld seam before grinding in this invention.

[0050] Figure 11b This is a view of the weld seam after grinding, as shown in the figure.

[0051] Label name in the image:

[0052] 1. Through-hole sleeve; 2. Welded parts; 3. Annular pad; 4. Welding torch; 5. Laser vision recognition sensor; 6. Assembly fixture; 7. Positioning and fixing fixture. Detailed Implementation

[0053] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0054] It should be noted that the terms such as "upper", "lower", "left", "right", "front", and "back" used in the invention are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0055] like Figure 1-9 As shown, the purpose of this invention is to provide a robotic welding method for nuclear power plant penetration sleeve 1. This technology changes the original K-type bevel of the welded part 2 (i.e., the reinforcing ring) of the penetration sleeve 1 to a V-type bevel, and performs welding in a single-sided welding and double-sided forming manner. Before welding, a spiral adjustment positioning device is used for positioning, and a positioning and fixing fixture 7 is used for assembly to ensure the consistency of the pre-welding assembly of penetration sleeves 1 of the same specification. Robotic automatic MAG welding is used to replace the original manual welding rod welding for welding nuclear power plant penetration sleeve 1, which improves welding efficiency and reduces the need for welders.

[0056] The invention will be further described below with reference to specific implementations.

[0057] In this embodiment, the through-hole sleeve 1 is made of φ273*16mm 20 steel, the reinforcing zone (i.e., the reinforcing ring with welded component 2, hereinafter referred to as "reinforcing zone") is a 20mm thick P265GH steel plate, the bevel angle is 40°~50°, the blunt edge requirement is 0~1mm, the assembly gap is 4~6mm, the weld length of the through-hole sleeve 1 is 946mm, and the shielding gas is 82% Ar + 18% CO2. The welding diagram is shown below. Figure 5 As shown, the main processes include the following:

[0058] Step 1: Machining and grinding the bevel of the through sleeve 1 and the reinforcing area;

[0059] Step 2: Overall inspection of the through sleeve 1 and the bevel of the reinforced area (this step is the preferred option and its effect is better when added);

[0060] Step 3: Adjust the height of the weld seam in the reinforced zone and the assembly gap using a spiral adjustment and positioning device;

[0061] Step 4: Use positioning and fixing fixture 7 to assemble the weld seams, and remove the spiral adjustment and positioning device. Attach a backing plate to the back of the weld seam;

[0062] Step 5: Hoist the workpiece (i.e., the through sleeve 1 and the fixed reinforcing area) and place it on the positioner for fixation. Position the welding robot and the positioner and adjust the angle of the welding torch 4.

[0063] Step Six: Write the robot welding program and simulate its operation to ensure error-free execution;

[0064] Step 7: Clean the weld seam before welding, select the welding process, and check the welding power supply function and gas flow rate;

[0065] Step 8: Welding of the through sleeve 1;

[0066] Step 9: Reset the welding robot and remove the through sleeve 1 from the positioner.

[0067] Step 10: Weld seam brushing and non-destructive testing.

[0068] The first step is to process and grind the bevel of the through sleeve 1 and the reinforcing area.

[0069] According to the process requirements, the reinforced area needs to be beveled. The bevel of the reinforced area is machined on a lathe, and the bevel angle is controlled within the range of 40° to 50° to ensure the accuracy and consistency of the bevel angle. After the bevel is completed, the weld area of ​​the through sleeve 1 (that is, the annular area from 25mm above the top surface of the reinforced area to 25mm below the ground surface of the reinforced area) is ground with an angle grinder, and the area around the area to be welded in the reinforced area is ground within a 25mm width to remove the rust on the surface of the base material and expose the metallic luster.

[0070] The second step is to conduct an overall inspection of the through sleeve 1 and the bevel of the reinforced area.

[0071] Use a welding inspection gauge to inspect the bevel, ensuring the bevel angle is within the range of 40° to 50° and the blunt edge is within the range of 0 to 2mm. Ensure there are no reverse bevels, delaminations, or bevel damage.

[0072] The third step is to use a spiral adjustment and positioning device to adjust the height of the weld seam in the reinforced zone and the assembly gap.

[0073] Stand the through-sleeve 1 upright on the ground, ensuring the weld is positioned above it. Tack-fix the four assembly fixtures 6 at 0°, 90°, 180°, and 270° positions, 110mm below the weld of the through-sleeve 1. Before tack-fixing, ensure the screws of the assembly fixtures 6 are pointing upwards to provide a lifting effect. After determining the height of the reinforced zone, adjust the weld assembly gap to control it within 4–6mm.

[0074] Fourth, use positioning and fixing fixture 7 to assemble the weld seams, and remove the spiral adjustment and positioning device. Attach a backing plate to the back of the weld seam.

[0075] After determining the location of the reinforcing area of ​​the through sleeve 1, four positioning and fixing fixtures 7 (which can be angle iron) are selected and spot-welded to the middle of the assembly fixture 6 (that is, at 45°, 135°, 225°, and 315° respectively on the outer perimeter of the through sleeve 1) to firmly connect the through sleeve 1 to the reinforcing area and ensure that no large welding deformation occurs during the welding process. The positioning and fixing fixtures 7 are made of the same material as the reinforcing area. After the positioning and fixing fixtures 7 are fixed, the assembly fixture 6 is removed to facilitate the use of the next workpiece.

[0076] After the through sleeve 1 is assembled, an annular backing plate 3 is pasted on the back of the weld. The annular backing plate 3 is made of high-temperature resistant ceramic material to avoid fusion with the welding rod and facilitate subsequent peeling. The shape of the annular backing plate 3 matches that of the through sleeve 1 (that is, the inner diameter of the annular backing plate 3 is equal to the outer diameter of the through sleeve 1), and the annular backing plate 3 has a groove at the weld (to facilitate double-sided welding). During the pasting process, the annular backing plate and the through sleeve 1 must be tightly fitted to the reinforcing area to avoid excessive gap between the annular backing plate and the workpiece, which would result in poor weld formation. To prevent the backing plate from falling off during the welding process, aluminum foil tape can be used to reinforce the backing plate.

[0077] Fifth step: hoist the workpiece and place it on the positioner for fixation. Then, position the welding robot and positioner and adjust the welding torch angle 4.

[0078] The through-hole sleeve 1 is hoisted using a crane and placed above the positioner. The positioner chuck is then gradually expanded. Once the workpiece is securely clamped, the positioner's rotation is adjusted according to the workpiece specifications to position the workpiece for either flat welding (PA) or horizontal welding (PC). For flat welding (PA), the workpiece stands upright on the positioner. Due to the positioner's height, when the length of the through-hole sleeve 1 exceeds 1500mm, the robot welding torch 4's stroke is limited, preventing welding. In this case, the positioner needs to be rotated 90° to change the workpiece to the horizontal welding (PC) position for welding.

[0079] After the position of the through-hole sleeve 1 is determined, the robot is moved to the attachment of the through-hole sleeve 1, and the position of the welding torch 4 is finely adjusted to be centered on the weld. After the welding robot is in position, the angle of the welding torch 4 is adjusted to 20° to 25°. The welding torch 4 is inserted into the weld, so that the tip of the welding wire is centered on the weld. The welding torch 4 is controlled to swing left and right for testing to ensure that the welding torch 4 will not collide with the workpiece.

[0080] The sixth step is to write the robot welding program and simulate its operation to ensure that the program runs correctly.

[0081] Write the welding program in the robot teach pendant to determine the movement trajectory of the robot and positioner. After the program is written, simulate the welding program in manual mode, turning off the arc ignition signal of the welding machine before running. During the operation, observe whether the robot and positioner move according to the expected trajectory. If the trajectory is found to deviate, the trajectory at that point needs to be corrected during the welding process.

[0082] Step 7: Clean the weld seam before welding, select the welding process, and check the welding power supply function and gas flow rate.

[0083] Use a wire brush to clean the weld seam and remove impurities such as rust and dust. Use acetone (or ethanol) to wipe the through sleeve 1 and the reinforcing plate to ensure cleanliness.

[0084] For the welding characteristics of the through-hole sleeve 1, welding processes were developed for flat welding (PA) and horizontal welding (PC) positions, resulting in two sets of automatic welding process parameters for different positions (the two differ only in some parameters during filler and capping welding, which will be detailed later). Based on the weld bead layout of the through-hole, the corresponding root pass, filler, and capping welding parameters were input into the motion program for each weld bead. Post-weld processing parameters were also added to prevent defects at the arc crater at the end of the weld.

[0085] The welding power source should be inspected according to the welding process requirements. The gas should be checked before welding to ensure that the welding machine is communicating normally and that the gas flow is sufficient. This will prevent the weld from being incomplete due to insufficient gas flow or communication errors, which could lead to potential quality problems.

[0086] Step 8: Welding of the through sleeve 1.

[0087] During welding, the arc initiation point is located on the inner side of the pipe wall inside the weld. After successful arc initiation, the positioner rotates according to a pre-programmed sequence and, through coordinated calculations with the welding torch 4, ensures the rotational linear velocity at the weld, i.e., the welding speed. During welding, the welding torch 4 only swings left and right relative to the weld's forward direction from its initial spatial position, completing one full rotation. The laser tracking function (i.e., the laser vision recognition sensor 5) is activated throughout the welding process. When the through-piece sleeve 1 deforms due to heat during welding, the robot welding torch 4's trajectory in the welding program is corrected in real time to ensure welding quality.

[0088] During the root pass welding, the welding current is 200A~280A, the welding voltage is 20~30V, the welding speed is 20cm / min~25cm / min, the oscillation amplitude is 1mm~3mm, the oscillation frequency is 1~2Hz, and the dwell time at both ends is 0.1s~0.3s. When finishing the arc, the post-processing current is 150A and the post-processing time is 2s.

[0089] During filler welding, the welding current is 180A~250A, the welding voltage is 18~28V, the welding speed is 20cm / min~30cm / min, the oscillation amplitude of the flat welding (PA) position is 2mm~6mm, the oscillation amplitude of the horizontal welding (PC) position is 1~4mm, the oscillation frequency is 1~2Hz, the dwell time at both ends is 0.1s~0.3s, the post-processing current is 150A and the post-processing time is 2s when the arc is closed.

[0090] For cover welding, the welding current is 200A~260A, the welding voltage is 20~28V, the welding speed for flat welding (PA) is 20cm / min~35cm / min, the oscillation amplitude is 2mm~7mm, the welding speed for horizontal welding (PC) is 25cm / min~40cm / min, the oscillation amplitude is 2~5mm, the oscillation frequency is 1~2Hz, the dwell time at both ends is 0.1s~0.3s, the post-processing current is 150A and the post-processing time is 2s when the arc is closed.

[0091] During the welding process, the interpass temperature and weld cleaning must be strictly performed in accordance with the process requirements. If the arc stops during the welding process, the joint must be thoroughly ground and brushed to ensure that the weld is clean and free of contaminants before welding can continue.

[0092] Step 9: The welding robot is reset, and the through sleeve 1 is removed from the positioner.

[0093] After welding is completed, the robot returns to its starting position to clean the welding torch and cut the wires. At the same time, it makes room for the hoisting of the through-hole sleeve 1 to avoid the workpiece colliding with the robot and causing economic losses.

[0094] A rotary positioner is used when the workpiece is positioned above the positioner. After securing the lifting sling to the through sleeve 1, gradually open the positioner chuck to remove the workpiece from the positioner.

[0095] Step 16: Post-weld cleaning and non-destructive testing of the weld.

[0096] After welding, the weld surface is brushed and cleaned. After cleaning, the weld appearance must be carefully inspected. If undercut is found, it must be ground and polished promptly. The cap weld joint must be ground smooth without reducing the thickness of the base material. After cleaning, the weld undergoes non-destructive testing, including visual inspection, penetrant testing, and ultrasonic testing.

[0097] The following are comparative data between the welding method of this invention and traditional manual electrode arc welding.

[0098] 1.1 Comparative Analysis of Welding Performance

[0099] Compared with the welding method of this invention, the physical and chemical test data are as follows:

[0100] Table 1. Physicochemical test data of tensile test

[0101]

[0102]

[0103] Table 2. Physicochemical test data of the impact test

[0104]

[0105] Table 3. Physicochemical test data for hardness testing

[0106]

[0107] As can be seen from the above, the tensile strength of the specimens welded using the present invention is better than that of the shielded metal arc welding joint, the toughness is slightly reduced, and the hardness is almost the same. Overall, the performance of the welded joints of the present invention meets the requirements and far exceeds the index requirements specified in the technical documents.

[0108] 1.2. Comparison of Welding Deformation

[0109] Measurements were taken of the products welded by manual electrode arc welding and robotic welding workstation in Workshop 1 for through-hole sleeves, and the data are shown in the table below.

[0110] Table 4 Comparison of Welding Deformation

[0111] Serial Number Welding methods Bevel form Deformation 1 Shielded metal arc welding K-type bevel 5～8° 2 This invention welding Single-sided V-groove 1～2°

[0112] As shown in the table above, compared with traditional manual shielded metal arc welding, the welding of this invention has a more uniform and faster welding speed, a smaller welding heat input, and a significantly smaller deformation after welding.

[0113] 1.3. Comparison of Welding Quality

[0114] The appearance of the through-hole sleeve 1 welded by manual shielded metal arc welding before and after grinding is shown below. Figure 10a and Figure 10b As shown;

[0115] The appearance of the through-hole sleeve 1 welded using the welding method of the present invention before and after grinding is shown in the figures below. Figure 11a and 11b As shown;

[0116] Depend on Figure 6 and Figure 7 As can be seen, the weld seam of this invention exhibits a uniform fish-scale pattern and consistent weld width. Ultrasonic testing revealed no internal defects in the weld seam, and the weld morphology is superior to that of traditional manual shielded metal arc welding.

[0117] 1.4. Comparison of Welding Efficiency

[0118] Using the same specifications, with a diameter of Comparing the welding times of a single workpiece using traditional manual shielded metal arc welding (SMAW) and the present invention with those of the through-hole sleeve 1, the results are as follows:

[0119] Manual shielded metal arc welding (SMAW): Traditional SMAW uses a double-sided V-groove for welding, with a total of 9-11 welds per workpiece. Each weld consumes approximately 10 weld beads, and the welding time is about 40 minutes. The total welding time for the through-hole sleeve 1 is 6-7 hours. Due to the multiple arc initiation and extinguishing of the welding rod, the weld needs to be ground multiple times during the welding process, with a total grinding time of about 2-3 hours. The workpiece assembly requirements before welding are relatively low, and the time required for assembling and grinding the workpiece is about 30 minutes. Because SMAW uses a double-sided welding method, the back of the weld needs to be cleaned, and a penetration test is performed after cleaning. Only after passing the test can the next step of welding be carried out, with a total time of about 2 hours. Including the personnel's rest time, the production time for a single through-hole sleeve 1 is about 14 hours.

[0120] Welding method of this invention: The welding method of this invention requires high pre-weld assembly. After changing the bevel shape, a ceramic backing needs to be attached to the back, eliminating the need for root cleaning. The pre-weld grinding and assembly time is about 1 hour. After assembly, welding is performed, with 4 layers and 8 passes. With each weld seam reprogrammed and taught, the welding time is about 6 hours; if it is fully automatic welding, the welding time is 1 to 2 hours.

[0121] Table 5 Comparison of Welding Efficiency

[0122]

[0123]

[0124] In summary, the welding efficiency of this invention is far superior to that of traditional manual shielded metal arc welding. Using a fully automated welding method, the welding efficiency can be increased by 7 times. Considering the 1.5-hour programming time, the welding efficiency is increased by at least 4 times.

[0125] 1.5. Economic Benefit Analysis

[0126] Statistics from the fabrication of the through-hole sleeve in Workshop 1 show that the fabrication of one through-hole sleeve for one island of the Hualong One reactor, using shielded metal arc welding, requires 5 nuclear-grade welders and 5 assistants, taking approximately 4 people's time to complete. The welding method of this invention requires 1 nuclear-grade welder and 2 assistants, and the construction cycle can be shortened by at least half. Using this invention for the fabrication of the through-hole sleeves for two units can save 1.04 million yuan in labor costs, as detailed in the table below.

[0127] Table 6 Economic Benefit Analysis

[0128]

[0129] By comparing the above data, it can be seen that the welding method provided by this invention solves the problems of labor shortage and low efficiency, and greatly reduces costs.

[0130] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A robotic welding method for nuclear power plant penetration sleeves, characterized in that, Includes the following steps: S1. Machin the welded parts with the required single-sided V-shaped bevel, and grind the areas to be welded on the through sleeve and the welded parts. S2. Use assembly tooling to adjust the weld height and assembly gap of the welded parts relative to the through sleeve to the set range; S3. The welding parts are fixed on the through sleeve by a positioning and fixing fixture, and a backing plate is provided on the back of the weld. S4. Install the through sleeve onto the positioner and adjust the welding robot's welding torch to a position that matches the weld seam; S5. Use a welding robot to weld the workpiece onto the through sleeve; S6. Clean the weld and perform non-destructive testing on it; The angle requirement for the single-sided V-shaped bevel in step S1 is 40° to 50°, and the blunt edge requirement is 0 to 2 mm; the through sleeve is made of carbon steel with a wall thickness of 16 to 40 mm; Step S5 specifically includes the following sub-steps: S51. Write the welding operation program for the welding robot and simulate the operation of the welding program; S52. Clean the weld and check the equipment condition; the equipment condition includes the current of the welding power source and the flow rate of the welding shielding gas. S53. Select the welding program parameters that match the position of the through sleeve, and run the welding program according to the parameters to perform welding. S54. The welding robot is reset, and the through-piece sleeve is removed from the positioner. The welding procedure parameters mentioned in step S53 include flat welding parameters and horizontal welding parameters; the welding mentioned in step S53 includes sequential root pass welding, fill pass welding and cap pass welding. The flat welding parameters include: During the root pass welding, the welding current is 200A~280A, the welding voltage is 20~30V, the welding speed is 20cm / min~25cm / min, the welding torch oscillation amplitude is 1mm~3mm, the welding torch oscillation frequency is 1~2Hz, and the welding torch dwell time at both ends of the oscillation amplitude is 0.1s~0.3s. When the arc is closed, the post-processing current is 150A and the post-processing time is 2s. During filler welding, the welding current is 180A~250A, the welding voltage is 18~28V, the welding speed is 20cm / min~30cm / min, the welding torch oscillation amplitude is 2mm~6mm, the welding torch oscillation frequency is 1~2Hz, the welding torch dwell time at both ends of the oscillation amplitude is 0.1s~0.3s, the post-processing current is 150A when the arc is closed, and the post-processing time is 2s when the arc is closed. During cover welding, the welding current is 200A~260A, the welding voltage is 20~28V, the welding speed of the welding torch is 20cm / min~35cm / min, the welding torch oscillation amplitude is 2mm~7mm, the welding torch oscillation frequency is 1~2Hz, the welding torch stays at both ends of the oscillation amplitude for 0.1s~0.3s, the post-processing current is 150A when the arc is closed, and the post-processing time is 2s when the arc is closed.

2. The robotic welding method for nuclear power plant penetration sleeves according to claim 1, characterized in that: The pad in step S3 is made of ceramic material; the pad is an annular shape that matches the through sleeve; the pad has a groove at the weld.

3. The robotic welding method for nuclear power plant penetration sleeves according to claim 1, characterized in that: The assembly tooling mentioned in step S2 is a spiral adjustment and positioning device; the positioning and fixing tooling mentioned in step S3 is several angle irons.

4. The robotic welding method for nuclear power plant penetration sleeves according to claim 1, characterized in that: The welding shielding gas in step S52 comprises 82% Ar and 12% CO2, and the flow rate of the welding shielding gas is 15-25 L / min.

5. The robotic welding method for nuclear power plant penetration sleeves according to claim 1, characterized in that: The horizontal welding parameters include: During the root pass welding, the welding current is 200A~280A, the welding voltage is 20~30V, the welding speed is 20cm / min~25cm / min, the welding torch oscillation amplitude is 1mm~3mm, the welding torch oscillation frequency is 1~2Hz, and the welding torch dwell time at both ends of the oscillation amplitude is 0.1s~0.3s. When the arc is closed, the post-processing current is 150A and the post-processing time is 2s. During filler welding, the welding current is 180A~250A, the welding voltage is 18~28V, the welding speed is 20cm / min~30cm / min, the welding torch oscillation amplitude is 1~4mm, the welding torch oscillation frequency is 1~2Hz, the welding torch dwell time at both ends of the oscillation amplitude is 0.1s~0.3s, the post-processing current is 150A when the arc is closed, and the post-processing time is 2s when the arc is closed. During cover welding, the welding current is 200A~260A, the welding voltage is 20~28V, the welding speed of the welding torch is 25cm / min~40cm / min, the welding torch oscillation amplitude is 2~5mm, the welding torch oscillation frequency is 1~2Hz, the welding torch stays at both ends of the oscillation amplitude for 0.1s~0.3s, the post-processing current is 150A when the arc is closed, and the post-processing time is 2s when the arc is closed.

6. The robotic welding method for nuclear power plant penetration sleeves according to claim 1, characterized in that: The set range for the pair gap in step S2 is 4 to 6 mm.

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