Segmented progressive preloading reverse deformation construction method

Abstract

The application discloses a kind of segmented progressive pre-load reverse deformation construction methods, it is related to nuclear island steel lining reverse deformation construction technical field, by the weld to be welded is divided into multiple continuous construction sections along the length direction, obtain the preset reverse deformation of current construction section, by pre-load applying device to current construction section pre-load is applied, make the reverse pre-deformation corresponding to preset reverse deformation on both sides of weld;Pre-load is executed welding by keeping, and pre-load is kept until construction section is cooled to preset temperature after welding;Release pre-load, measure residual deformation, according to the deviation of residual deformation and preset reverse deformation correct preset reverse deformation of next construction section;Pre-load applying device is progressively moved to next construction section cycle construction, until all construction sections are welded complete.The application solves the problem that the adaptability of steel lining long weld is poor, the reverse deformation quantity has no feedback correction and the cooling shrinkage deformation lacks constraint control.

Description

Technical Field

[0001] This invention relates to the field of anti-deformation construction technology for nuclear island steel linings, and particularly to a segmented progressive preload anti-deformation construction method. Background Technology

[0002] The steel liner of the nuclear island is a crucial component of the reactor building's containment structure. Constructed from welded steel plates, its welding deformation control directly impacts the dimensional accuracy of the liner's inner wall and the subsequent installation of equipment. Steel liner welds include longitudinal and circumferential welds, with angular deformation being the primary form of deformation. To control angular deformation, engineering has evolved from post-weld straightening to pre-weld pre-deformation: early methods involved hammering, hot straightening, or mechanical straightening of welded components, resulting in numerous procedures and inconsistent straightening quality. With the development of welding deformation theory, preventative measures such as rigid fixing and reverse deformation methods have gradually emerged. The reverse deformation method, in particular, pre-induces deformation on both sides of the weld in the opposite direction to the welding deformation, thus offsetting residual angular deformation after welding.

[0003] Currently, the common practice for reverse deformation in steel lining welding is to set the reverse deformation amount for the entire weld all at once, using jigs, bracing components, or wedges to pre-bend the plate along the entire weld before welding. This approach has the following drawbacks: First, applying reverse deformation along the length of a long weld requires the reverse deformation device to cover the entire weld, resulting in a large device size, difficulty in assembly and disassembly, and poor adaptability to deformation differences in different sections. Second, the reverse deformation amount is set based on empirical values, lacking actual measurement feedback on residual deformation after welding. When the deformation amounts in different sections of the weld are inconsistent, it is impossible to correct them segment by segment, and residual deformation accumulates along the weld. Third, the offsetting relationship between deformation caused by welding thermal cycles and reverse deformation is affected by multiple factors such as plate thickness, bevel type, and welding parameters. When the same reverse deformation amount is used for the entire weld, the actual residual deformation of each section has large dispersion. Fourth, the shrinkage deformation during the cooling stage after welding lacks constraint control, and the deformation rebound during the cooling process affects the final accuracy. Summary of the Invention

[0004] The main objective of this invention is to propose a segmented progressive preload anti-deformation construction method, which aims to solve the problems of poor adaptability of one-time overall anti-deformation in the existing anti-deformation of long weld seams in steel linings, lack of actual measurement feedback on the amount of anti-deformation so as to make segmented corrections, and lack of constraint control on cooling shrinkage deformation.

[0005] To achieve the above objectives, in a first aspect, the present invention proposes a segmented progressive preload anti-deformation construction method, comprising: The weld seam to be welded is divided into multiple continuous construction sections along its length; Obtain the preset reverse deformation amount of the current construction section; A preload is applied to the current construction section by a preload application device, so that the weld on both sides of the current construction section produces a reverse pre-deformation corresponding to the preset reverse deformation amount; Maintain the preload, perform welding on the current construction section, and maintain the preload after welding until the current construction section cools to a preset temperature; Release the preload of the current construction segment, measure the residual deformation of the current construction segment, and correct the preset reverse deformation of the next construction segment based on the deviation between the residual deformation and the preset reverse deformation. The preload application device is moved progressively to the next construction segment, and then the step of obtaining the preset anti-deformation amount of the current construction segment is performed until all construction segments are welded.

[0006] The technical solution of this invention divides the weld seam to be welded into multiple continuous construction segments along its length, thereby decomposing the anti-deformation control of the long weld seam from overall control of the entire weld seam into segment-by-segment control. The anti-deformation device only needs to cover the current construction segment. By acquiring the preset anti-deformation amount of the current construction segment, the anti-deformation amount of each segment is determined according to the actual situation of that segment. A preload is applied to the current construction segment through a preload application device, causing reverse pre-deformation corresponding to the preset anti-deformation amount to occur on both sides of the weld seam, providing a reserved deformation in the opposite direction for welding angular deformation. By maintaining the preload during welding and maintaining the preload after welding until the current construction segment cools to the preset temperature, the reverse pre-deformation during the welding and cooling stages is always constrained, suppressing the rebound of cooling shrinkage deformation. By releasing the preload and measuring the residual deformation amount of the current construction segment, the preset anti-deformation amount of the next construction segment is corrected according to the deviation between the residual deformation amount and the preset anti-deformation amount, so that the anti-deformation amount of subsequent construction segments is corrected segment by segment based on the actual measurement results of the previous construction segment. By progressively moving the preload application device to the next construction segment and executing it cyclically, the anti-deformation device advances segment by segment with the construction segment. Therefore, the anti-deformation control has the ability to adapt and correct step by step, solving the problems of poor adaptability of one-time overall anti-deformation, lack of measured feedback on anti-deformation amount which makes it impossible to correct step by step, and lack of constraint control for cooling shrinkage deformation. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0008] Figure 1 The flowchart is for the segmented progressive preload anti-deformation construction method provided by the present invention.

[0009] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0010] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0011] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0012] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0013] It should be noted that, in this application, a construction segment refers to a continuous section obtained by dividing the weld to be welded along its length; the preset reverse deformation amount refers to the target value of the deformation amount generated in advance on both sides of the weld in the construction segment, which is opposite to the direction of welding deformation; reverse pre-deformation refers to the pre-set deformation on both sides of the weld generated by preloading, which is opposite to the direction of welding angular deformation; the current construction segment refers to the construction segment that is currently performing reverse deformation and welding, and the next construction segment refers to the construction segment located after the current construction segment according to the numbering sequence; residual deformation amount refers to the amount of angular deformation remaining on both sides of the weld after the preload is released. The above terms are only used to describe the scheme of this application and do not constitute a limitation on other meanings. The terminology includes and its variations are intended to cover non-exclusive inclusion. The calculation formulas, judgment criteria and parameters in this specification are all theoretical models or design parameters, which can be adjusted within a reasonable range according to the actual engineering situation. This invention does not involve limiting specific test results.

[0014] This invention proposes a segmented progressive preload anti-deformation construction method.

[0015] Please see Figure 1 For ease of understanding, this segmented progressive preload anti-deformation construction method includes: S100. Divide the weld seam to be welded into multiple continuous construction sections along the length direction; S200: Obtain the preset reverse deformation amount of the current construction section; S300. Apply a preload to the current construction section through a preload application device, so that the weld on both sides of the current construction section produces a reverse pre-deformation corresponding to the preset reverse deformation amount.

[0016] It should be noted that the direction of the reverse pre-deformation is opposite to the direction of the welding angle deformation, and its magnitude is equal to the preset reverse deformation amount.

[0017] S400. Maintain the preload, perform welding on the current construction section, and maintain the preload after welding until the current construction section cools to a preset temperature; S500: Release the preload of the current construction segment, measure the residual deformation of the current construction segment, and correct the preset reverse deformation of the next construction segment based on the deviation between the residual deformation and the preset reverse deformation. S600, The preload application device is moved progressively to the next construction segment, and the process returns to the step of obtaining the preset anti-deformation amount of the current construction segment until all construction segments are welded.

[0018] In this embodiment, by dividing the weld seam to be welded into multiple continuous construction segments along its length, the anti-deformation control of the long weld seam is decomposed from the overall control of the entire weld seam into segment-by-segment control, and the anti-deformation device only needs to cover the current construction segment. By obtaining the preset anti-deformation amount of the current construction segment, the anti-deformation amount of each segment is determined according to the actual situation of that segment. By applying a preload to the current construction segment through a preload application device, the weld seam is subjected to reverse pre-deformation on both sides corresponding to the preset anti-deformation amount, providing a reserved deformation in the opposite direction for welding angular deformation. By maintaining the preload during welding and maintaining the preload after welding until the current construction segment cools to the preset temperature, the reverse pre-deformation during the welding and cooling stages is always constrained, suppressing the rebound of cooling shrinkage deformation. By releasing the preload and measuring the residual deformation amount of the current construction segment, the preset anti-deformation amount of the next construction segment is corrected according to the deviation between the residual deformation amount and the preset anti-deformation amount, so that the anti-deformation amount of subsequent construction segments is corrected segment by segment based on the actual measurement results of the previous construction segment. By progressively moving the preload application device to the next construction segment and executing it cyclically, the anti-deformation device advances segment by segment with the construction segment. Therefore, the anti-deformation control has the ability to adapt and correct step by step, solving the problems of poor adaptability of one-time overall anti-deformation, lack of measured feedback on anti-deformation amount which makes it impossible to correct step by step, and lack of constraint control for cooling shrinkage deformation.

[0019] In one embodiment, the length of each construction segment is 500mm to 1000mm; Step S100 includes: S110. An overlapping area is set between two adjacent construction sections; wherein the length of the overlapping area is 50mm~100mm; S120. Number the construction sections sequentially according to the welding sequence to obtain the numbering information of each construction section.

[0020] It should be noted that the length of the construction section should be matched with the effective range of the preload application device and the length of a single weld: if the section length is too short, the device will move frequently and there will be many weld joints; if the section length is too long, the amount of reverse deformation will be difficult to match the deformation characteristics of the section. The overlapping area ensures that the welds of adjacent construction sections have a common coverage area at the junction, avoiding the leaving of incomplete fusion or welding defects at the junction due to segmented welding. The numbering information provides a basis for the processing order and feedback correction order of each construction section, and the next construction section is determined according to the number.

[0021] In this embodiment, by setting the length of the construction section to 500mm~1000mm and setting an overlap area of ​​50mm~100mm between adjacent construction sections, the effective range of the anti-deformation device is matched with the welding heat-affected zone. The overlap area ensures the welding continuity of adjacent construction sections and no missing weld gaps. The processing order and feedback correction order of each construction section are clearly defined by numbering according to the welding sequence.

[0022] In one embodiment, step S200 includes: S210. Based on the plate thickness, weld bevel type, and welding process parameters of the plate where the current construction section is located, query the corresponding anti-deformation amount from the preset anti-deformation amount data table to obtain the preset anti-deformation amount; or, S220. Based on the plate thickness, weld bevel form, and welding process parameters of the plate where the current construction section is located, the corresponding reverse deformation amount is calculated using a finite element calculation model to obtain the preset reverse deformation amount; wherein, the preset reverse deformation amount is 1.1 to 1.3 times the expected value of the welding angle deformation.

[0023] Specifically, based on the plate thickness, weld bevel type, and welding process parameters of the plate in the current construction section, the corresponding anti-deformation amount is retrieved from the preset anti-deformation amount data table to obtain the preset anti-deformation amount. It should be noted that the preset anti-deformation amount data table can be compiled from historical construction data or process evaluation data under similar plate thicknesses and bevel types, and the table is indexed by plate thickness, bevel type, and welding process parameters.

[0024] Of course, the corresponding reverse deformation amount can also be calculated using a finite element model based on the plate thickness, weld bevel type, and welding process parameters of the plate in the current construction section, thus obtaining the preset reverse deformation amount. It should be noted that the finite element model takes plate thickness, bevel type, and welding process parameters as input to calculate the expected value of weld angle deformation for that section, and is suitable for new plate thicknesses or new bevel types where historical data is lacking.

[0025] In both examples, the preset reverse deformation amount is 1.1 to 1.3 times the expected value of the weld corner deformation. It should be noted that taking 1.1 to 1.3 times the expected value of the weld corner deformation is to reserve compensation for local plastic deformation of the plate and elastic rebound of the device during the welding process: if it is less than 1.1 times, the compensation is insufficient and the residual deformation may be positive; if it is more than 1.3 times, the reverse pre-deformation is too large, and the plate on both sides of the weld may suffer plastic damage or reverse residual deflection.

[0026] In this embodiment, the preset reverse deformation amount is calculated by querying the preset reverse deformation amount data table or by using the finite element calculation model based on the plate thickness, weld groove form and welding process parameters, and is taken as 1.1 to 1.3 times the expected value of welding angle deformation, so that the initial reverse deformation amount has a definite theoretical or data basis. The amplification factor of 1.1 to 1.3 times is reserved to compensate for the plastic deformation loss during the welding process, so as to avoid insufficient reverse deformation amount.

[0027] In one embodiment, the preload application device is a combination of a hydraulic jack and an anti-deformation beam, or a counterweight. Step S300 includes: Preload is applied to the current construction section in stages. After each stage of loading, the reverse pre-deformation on both sides of the weld in the current construction section is measured. Loading is stopped when the reverse pre-deformation reaches the preset reverse deformation.

[0028] Specifically, the preload application device is a combination of hydraulic jacks and anti-deformation beams, or a counterweight. Preload is applied in stages to the current construction section. After each stage, the reverse pre-deformation on both sides of the weld in the current construction section is measured. Loading stops when the reverse pre-deformation reaches the preset reverse deformation amount. It should be noted that when using the combination of hydraulic jacks and anti-deformation beams, the hydraulic jacks pressurize the anti-deformation beams, which then apply pressure to the plates on both sides of the weld, causing the plates to bend in the reverse direction around the weld. When using counterweights, the counterweights are placed at predetermined positions on both sides of the weld plates, using gravity to generate reverse pre-deformation, suitable for situations where site conditions limit the operation of hydraulic equipment. Staged loading causes the reverse bending of the plates on both sides of the weld to occur gradually. The measured reverse pre-deformation after each stage serves as the control basis, avoiding excessive loading at once that could cause localized plastic damage to the plates.

[0029] In this embodiment, a combination of hydraulic jacks and anti-deformation beams or counterweights is used as a preload application device, and the preload is applied to the current construction section in stages. After each stage of loading, the reverse pre-deformation on both sides of the weld is measured. Loading is stopped when the preset reverse deformation amount is reached, so that the reverse pre-deformation is formed step by step. The measured deformation amount is used as the basis for loading control, avoiding local plastic damage to the plate caused by excessive loading at one time.

[0030] In one embodiment, step S400 includes: S410. While maintaining the preload, perform root pass welding, fill welding and cover welding on the current construction section, with the welding direction symmetrical from the middle to both ends of the current construction section; S420. After welding is completed, continue to maintain the preload and monitor the weld temperature of the current construction section until the current construction section cools down to the preset temperature.

[0031] It should be noted that the root pass welding is used to form the fusion at the weld root, the fill pass welding is used to fill most of the volume of the bevel, and the cover pass welding is used to form the weld surface shape; the welding direction is symmetrical from the middle of the construction section to both ends, so that the welding heat input is symmetrically distributed along the length of the section, and the thermal shrinkage at both ends of the section occurs symmetrically in time, reducing additional torsional deformation; the preload is maintained throughout the welding and cooling process, the reverse pre-deformation is always controlled, and the cooling shrinkage is completed under constraint, avoiding deformation springback during the cooling stage.

[0032] In this embodiment, by performing root pass welding, filler welding, and cover pass welding while maintaining a preload, the welding direction is symmetrical from the middle of the construction section to both ends. This ensures that the construction section is always under reverse pre-deformation constraint throughout the welding process. Furthermore, symmetrical welding ensures that the heat input is symmetrically distributed along the length of the section, reducing additional deformation caused by the welding process itself. After welding is completed, the preload is maintained and the weld temperature is monitored until it reaches the preset temperature, allowing cooling and shrinkage to be completed under constraint, thus avoiding deformation and springback during the cooling stage.

[0033] In one embodiment, the preset temperature is 50℃~100℃. The weld temperature of the current construction section is monitored by an infrared thermometer. When the weld temperature drops below the preset temperature, the step of releasing the preload of the current construction section is performed.

[0034] It should be noted that the infrared thermometer is a non-contact temperature measurement device that can continuously monitor the weld temperature under load. The preset temperature is set at 50℃~100℃ because the weld metal has low strength and its deformation is not yet stable at high temperatures. Releasing the constraint at this temperature may cause the unstable deformation to spring back. After the temperature drops below the preset temperature, the deformation of the weld metal is basically stable, and the amount of springback caused by releasing the preload is basically determined, so that subsequent measurements and corrections have a stable reference.

[0035] In this embodiment, by setting the preset temperature to 50℃~100℃, the weld temperature is monitored by an infrared thermometer. The preload is released only when the temperature drops below the preset temperature, so that the timing of the release of the preload corresponds to the mechanical state of the weld metal. Releasing the constraint at high temperature may cause the deformation to spring back before it has stabilized. Releasing it after the temperature drops to the preset temperature means that the amount of springback has been basically determined.

[0036] In one embodiment, step S500 includes: S510. Release the preload of the current construction section; S520. The residual deformation on both sides of the weld in the current construction section is measured by a measuring template or a laser rangefinder. The measuring template is fitted to the surface of the plate on both sides of the weld in a preset shape. The angular deformation is judged by the gap or degree of fit between the template and the plate. The laser rangefinder measures the displacement of selected measuring points on both sides of the weld and converts it into angular deformation. The measurement accuracy and efficiency are higher.

[0037] S530. Calculate the deviation between the residual deformation and the preset reverse deformation. S540. The preset anti-deformation amount of the next construction section is corrected to the difference between the current preset anti-deformation amount and the deviation.

[0038] The residual deformation is measured in the positive direction of the weld angle deformation, while the preset reverse deformation is measured in the reverse direction of the pre-deformation. Let the preset reverse deformation of the current construction section be... The measured residual deformation is ,deviation Calculate using Formula 1:

[0039] when For positive and When the value is greater than 0, it indicates that the reverse pre-deformation has not completely offset the welding angle deformation, and the amount of reverse deformation needs to be increased in the next construction section; when negative and If the value is less than 0, it indicates that the reverse pre-deformation is excessive, and the amount of reverse deformation needs to be reduced in the next construction section.

[0040] Preset reverse deformation amount for the next construction section Calculate using Formula 2:

[0041] The following is an exemplary calculation process: Let the preset anti-deformation amount of the current construction section be... =6.0mm, residual deformation measured after welding cooling and release of preload. =+2.0mm, meaning insufficient reverse pre-deformation, with a remaining positive angular deformation of 2.0mm, then the deviation... =2.0 6.0= 4.0mm; the preset reverse deformation amount for the next construction section is corrected to =6.0 ( 4.0) = 10.0 mm, meaning the next construction section will be constructed with a preset anti-deformation amount of 10.0 mm, in order to converge the residual deformation amount to near zero. The above values ​​are only used as examples to illustrate the correction calculation process and do not constitute a limitation on engineering parameters.

[0042] In this embodiment, after releasing the preload, the residual deformation on both sides of the weld is measured using a measuring template or a laser rangefinder. The deviation between the residual deformation and the preset reverse deformation is calculated, and the preset reverse deformation of the next construction segment is corrected to the difference between the current preset reverse deformation and the deviation. This makes the measured residual deformation of each construction segment the correction input for the reverse deformation of the next construction segment. The reverse deformation converges adaptively with the construction process, and the residual deformation of each segment of the weld tends to be consistent.

[0043] In one embodiment, step S600 includes: S610. Along the travel track laid on one side of the weld seam to be welded, move the preload application device from the current construction section to the corresponding position of the next construction section; S620. After the movement is completed, check the loading position of the preload application device to align the loading point of the preload application device with both sides of the weld in the next construction section.

[0044] It should be noted that the traveling track enables the preload application device to move directionally along the weld direction. The device can be transferred quickly and maintain its posture during the movement. After the movement is completed, the loading position is checked to avoid additional bending moment caused by the loading point deviation, and to ensure that the reverse pre-deformation acts symmetrically on the plates on both sides of the weld.

[0045] In this embodiment, the preload application device is moved progressively to the next construction section by a walking track laid on one side of the weld to be welded, and the loading position is checked after the movement to align the loading point with both sides of the weld in the next construction section. This makes the device transfer process fast and the positioning accurate, avoiding positioning errors and damage caused by manual handling of the device.

[0046] In one embodiment, the weld to be welded is a longitudinal or circumferential weld of the nuclear island steel lining, and the welding sequence is longitudinal weld first, then circumferential weld. At the T-junction where the longitudinal seam and the circumferential seam meet, leave a section of weld seam with a length of 50mm to 250mm unwelded. After the adjacent weld seam is completed, the weld seam will be repaired.

[0047] It should be noted that the T-junction is the stress convergence zone of the longitudinal seam and the circumferential seam. Welding there first will lead to stress concentration and deformation superposition. The reserved section allows the convergence zone to be welded after the adjacent weld is completed, so that the welding stress and deformation are released step by step. The reserved length of 50mm to 250mm ensures that the welds on both sides of the convergence zone are not mutually constrained before the weld is repaired. At the same time, the limited length of the reserved section does not affect the inspection arrangement of the overall sealing performance of the lining.

[0048] In this embodiment, by adopting a welding sequence of longitudinal seam first and then circumferential seam for the longitudinal seam or circumferential seam of the nuclear island steel lining, and reserving a 50mm to 250mm weld at the T-junction where the longitudinal seam and circumferential seam intersect, and then supplementing the weld after the adjacent weld is completed, the welding stress and deformation at the intersection of the longitudinal and circumferential seams are released in stages, avoiding stress superposition and deformation out of control caused by simultaneous welding of multiple welds at the intersection.

[0049] In one embodiment, after step S600, the method further includes: S700. Measure the overall profile deviation of the weld to be welded; S800. When the overall profile deviation exceeds the preset allowable deviation, select the weld segment with the excessive deviation, reapply the preload, and perform compensation welding treatment until the overall profile deviation meets the preset allowable deviation.

[0050] It should be noted that the compensation welding process involves overlaying or remelting the weld section where the deviation exceeds the limit to correct the local profile; the preload is reapplied so that the compensation welding is carried out under the reverse pre-deformation constraint to avoid the compensation welding introducing new deformation.

[0051] In this embodiment, after all construction sections are welded, the overall contour deviation of the weld to be welded is measured. When the overall contour deviation exceeds the preset allowable deviation, the weld section with the excessive deviation is selected, the preload is reapplied, and the compensation welding process is performed until the overall contour deviation meets the preset allowable deviation. This allows the segment-by-segment control results to be finally verified and compensated at the level of the entire weld, ensuring the overall forming accuracy of the weld.

[0052] The above description is merely an exemplary embodiment of this application and does not limit the scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the application specification and drawings, or direct / indirect applications in other related technical fields, are included within the protection scope of this application.

Claims

1. A segmented progressive preload anti-deformation construction method, characterized in that, include: The weld seam to be welded is divided into multiple continuous construction sections along its length; Obtain the preset reverse deformation amount of the current construction section; A preload is applied to the current construction section by a preload application device, so that the weld on both sides of the current construction section produces a reverse pre-deformation corresponding to the preset reverse deformation amount; Maintain the preload, perform welding on the current construction section, and maintain the preload after welding until the current construction section cools to a preset temperature; Release the preload of the current construction segment, measure the residual deformation of the current construction segment, and correct the preset reverse deformation of the next construction segment based on the deviation between the residual deformation and the preset reverse deformation. The preload application device is moved progressively to the next construction segment, and then the step of obtaining the preset anti-deformation amount of the current construction segment is performed until all construction segments are welded.

2. The segmented progressive preload anti-deformation construction method as described in claim 1, characterized in that, The length of each construction segment is 500mm~1000mm; The step of dividing the weld seam to be welded into multiple continuous construction segments along its length includes: An overlapping area is provided between two adjacent construction sections; wherein the length of the overlapping area is 50mm~100mm; The construction sections are numbered sequentially according to the welding order to obtain the numbering information for each construction section.

3. The segmented progressive preload anti-deformation construction method as described in claim 1, characterized in that, The step of obtaining the preset reverse deformation amount of the current construction section includes: Based on the plate thickness, weld bevel type, and welding process parameters of the plate where the current construction section is located, the corresponding anti-deformation amount is retrieved from the preset anti-deformation amount data table to obtain the preset anti-deformation amount; or, Based on the plate thickness, weld bevel form, and welding process parameters of the plate where the current construction section is located, the corresponding reverse deformation amount is calculated through a finite element calculation model to obtain the preset reverse deformation amount; wherein, the preset reverse deformation amount is 1.1 to 1.3 times the expected value of the welding angle deformation.

4. The segmented progressive preload anti-deformation construction method as described in claim 1, characterized in that, The preload application device is a combination of a hydraulic jack and an anti-deformation beam, or a counterweight; The step of applying a preload to the current construction section using a preload application device, so that both sides of the weld in the current construction section produce a reverse pre-deformation corresponding to the preset reverse deformation amount, includes: Preload is applied to the current construction section in stages. After each stage of loading, the reverse pre-deformation on both sides of the weld in the current construction section is measured. Loading is stopped when the reverse pre-deformation reaches the preset reverse deformation.

5. The segmented progressive preload anti-deformation construction method as described in claim 4, characterized in that, The steps of maintaining the preload, performing welding on the current construction section, and maintaining the preload until the current construction section cools to a preset temperature after welding include: While maintaining the preload, perform root pass welding, fill welding and cover welding on the current construction section, with the welding direction proceeding symmetrically from the middle to both ends of the current construction section; After welding is completed, the preload is maintained and the weld temperature of the current construction section is monitored until the current construction section cools down to the preset temperature.

6. The segmented progressive preload anti-deformation construction method as described in claim 5, characterized in that, The preset temperature is 50℃~100℃. The weld temperature of the current construction section is monitored by an infrared thermometer. When the weld temperature drops below the preset temperature, the step of releasing the preload of the current construction section is executed.

7. The segmented progressive preload anti-deformation construction method as described in claim 1, characterized in that, The steps of releasing the preload of the current construction segment, measuring the residual deformation of the current construction segment, and correcting the preset reverse deformation of the next construction segment based on the deviation between the residual deformation and the preset reverse deformation include: Release the preload of the current construction section; The residual deformation on both sides of the weld in the current construction section is measured using a measuring template or a laser rangefinder. Calculate the deviation between the residual deformation and the preset reverse deformation. The preset anti-deformation amount of the next construction section is corrected to the difference between the current preset anti-deformation amount and the deviation.

8. The segmented progressive preload anti-deformation construction method as described in claim 7, characterized in that, The step of progressively moving the preload application device to the next construction section includes: The preload application device is moved from the current construction section to the corresponding position in the next construction section along the travel track laid on one side of the weld seam to be welded; After the movement is completed, check the loading position of the preload application device to align the loading point of the preload application device with both sides of the weld in the next construction section.

9. The segmented progressive preload anti-deformation construction method as described in any one of claims 1 to 8, characterized in that, The weld to be welded is the longitudinal or circumferential weld of the nuclear island steel lining, and the welding sequence is longitudinal weld first, then circumferential weld. At the T-junction where the longitudinal seam and the circumferential seam meet, leave a section of weld seam with a length of 50mm to 250mm unwelded. After the adjacent weld seam is completed, the weld seam will be repaired.

10. The segmented progressive preload anti-deformation construction method as described in any one of claims 1 to 8, characterized in that, The method further includes the following steps: Moving the preload application device progressively to the next construction segment, returning to the step of obtaining the preset anti-deformation amount of the current construction segment, and continuing until all construction segments are welded. Measure the overall profile deviation of the weld seam to be welded; When the overall profile deviation exceeds the preset allowable deviation, the weld segment with the excessive deviation is selected, the preload is reapplied, and compensation welding is performed until the overall profile deviation meets the preset allowable deviation.

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