Laser processing device and method for nuclear reactor shell

Abstract

The invention relates to the technical field of laser welding, and discloses a laser machining device and method for a nuclear reactor shell, and the method comprises the steps that a shell plate welding area to be welded is subjected to surface modification pretreatment; the laser processing device is used for carrying out initial welding on the pretreated shell plate, in the initial welding process, the temperature sensing assembly is used for monitoring temperature distribution of the welding area in real time, and temperature information of the welding area is obtained; the temperature information is input into a preset temperature-deformation prediction model for prediction of a variable trend and a stress distribution condition so as to obtain a first prediction result; based on the obtained first prediction result, the welding parameters of the laser processing device are dynamically adjusted for the first time; welding deformation and stress concentration are effectively coped with, the welding quality and structural strength of the nuclear reactor shell after laser welding are improved, and the reliability and safety of the nuclear reactor shell during use are effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of laser welding, and in particular to a laser processing device and a processing method for a nuclear reactor shell. Background Art

[0002] With the continuous development of nuclear energy technology, nuclear reactors, as the core equipment of nuclear power plants, the quality of their shell manufacturing is directly related to the safety and reliability of nuclear power plants. Nuclear reactor shells are usually made of extra-thick steel plates with a thickness of more than 100 mm. They need to withstand extreme working environments such as high temperature, high pressure and strong radiation, and have extremely stringent requirements on their welding quality and structural strength. Laser welding technology has the advantages of high energy density, fast welding speed, small heat-affected zone and small welding deformation, and has gradually been applied to the manufacturing process of nuclear reactor shells. However, for plates of this thickness, traditional laser welding processes still face many challenges.

[0003] The existing nuclear reactor shell laser welding method usually directly welds thick plates, and lacks real-time monitoring and response to the temperature field during the welding process. Since the thick plate has low absorption efficiency of laser energy, the heat input is uneven, and it is difficult to timely detect and respond to thermal deformation and stress concentration problems during welding. There is a lack of real-time adjustment functions based on problems encountered during the welding process. Welding defects such as cracks, pores and deformation are prone to occur in the weld area, which seriously affects the welding quality and structural strength, resulting in poor reliability and safety of the nuclear reactor shell. Summary of the invention

[0004] The purpose of the present invention is to provide a laser processing device and a processing method for a nuclear reactor shell, which can effectively deal with welding deformation and stress concentration, improve the welding quality and structural strength of the nuclear reactor shell after laser welding, and effectively improve the reliability and safety of the nuclear reactor shell during use.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A laser processing method for a nuclear reactor shell is designed, comprising: S1. Performing surface modification pretreatment on the welding area of ​​the shell plate to be welded; S2. Performing initial welding on the pre-treated shell plate by a laser processing device. During the initial welding process, a temperature sensor component is used to monitor the temperature distribution of the welding area in real time to obtain temperature information of the welding area, and the temperature information is input into a preset temperature-deformation prediction model to predict the deformation trend and stress distribution, so as to obtain a first prediction result. S3. Based on the first prediction result obtained, dynamically adjust the welding parameters of the laser processing device for the first time to perform the main welding stage, wherein the welding parameters include adjusting the output power, welding speed and focal position of the laser beam; S4. During the main welding stage, the molten pool observation system monitors the geometric shape and flow characteristics of the molten pool during welding and generates molten pool shape information; S5. Continuously correct the first prediction result through the molten pool morphology information to obtain a second prediction result, and dynamically adjust the welding parameters of the laser processing device for a second time through the second prediction result until the welding is completed to obtain a nuclear reactor shell.

[0006] Optionally, the S1 specifically includes: S11, cleaning the welding area of ​​the shell plate to be welded, wherein the cleaning process is to use a degreasing agent or an alkaline cleaning solution to remove grease and oxide scale on the surface; S12, performing surface treatment of fine grinding and polishing on the cleaned welding area; S13, spraying or electroplating the surface of the welding area after the surface treatment to form a uniform high-absorption coating in the welding area, wherein the material of the high-absorption coating includes black chrome or black nickel having a high absorption rate to laser; S14, micro-scale structural processing of the weld area with a high absorptivity coating by pulsed laser; S15. Coating an anti-oxidation film on the welding area where the micro-scale structure is formed.

[0007] Optionally, the S14 specifically includes: S141, adjusting pulse laser processing parameters according to characteristic parameters and thickness parameters of the nuclear reactor shell; S142, presetting the shape of the microscale structure, wherein the predefined shape of the microscale structure includes periodically arranged micro-grooves or micro-protrusions, and the arrangement is a regular two-dimensional array; S143. According to the set pulse laser processing parameters and the preset shape of the micro-scale structure, the welding area coated with the high absorption rate coating is subjected to micro-scale structural processing, and the preset micro-scale structure is etched on the surface of the welding area by utilizing the nonlinear optical effect of the laser.

[0008] Optionally, the S2 specifically includes: S21, fixing the shell plate with the micro-scale structure on the welding platform of the laser processing device through a clamping device; S22, arranging a temperature sensing assembly in the welding area, wherein the temperature sensing assembly includes a plurality of infrared temperature sensors, and the infrared temperature sensors are arranged in a matrix along the welding seam direction, and the spacing between adjacent infrared temperature sensors is 5 mm to 10 mm; S23, setting initial welding parameters of the laser processing device; S24, starting the laser processing device to perform initial welding on the shell plate, the laser beam continuously moves along the weld direction, and the temperature sensing component monitors the temperature information of the welding area in real time, the temperature information including the molten pool temperature, the heat affected zone temperature, the welding heat input and the thermal gradient; S25, inputting the temperature information into a preset temperature-deformation prediction model, wherein the temperature-deformation prediction model is based on a finite element analysis method, combined with characteristic parameters and thickness parameters of the shell plate material and welding process parameters, to simulate and calculate the thermal deformation and stress distribution caused by temperature changes during the welding process; S26. Obtain a first prediction result through simulation calculation of the temperature-deformation prediction model, wherein the first prediction result includes a transient temperature field distribution and a deformation trend diagram of the welding area.

[0009] Optionally, the characteristic parameters of the shell plate material include thermophysical performance parameters and mechanical performance parameters, the thermophysical performance parameters include thermal conductivity, specific heat capacity and thermal expansion coefficient, and the mechanical performance parameters include Young's modulus, Poisson's ratio and yield strength.

[0010] Optionally, the S3 specifically includes: S31, analyzing the transient temperature field distribution and deformation trend diagram obtained from the temperature-deformation prediction model, identifying the locations in the deformation trend diagram where the temperature distribution is uneven, the thermal stress is concentrated, or the locations exceed the preset deformation threshold, and marking them as abnormal areas; S32, analyzing the abnormal area to obtain abnormal information, wherein the abnormal information includes a peak value, an area of ​​the abnormal area, and a corresponding abnormal type, and dynamically adjusting the laser beam output power and welding speed of the laser processing device based on the obtained abnormal information; S33. According to the material thickness and melting depth requirements, the focal position of the laser beam is dynamically adjusted. If the melting depth needs to be increased, the focal position is adjusted downward, that is, the focal point is located 3 mm to 6 mm below the surface of the shell plate; if the melting depth needs to be reduced, the focal position is adjusted upward, that is, the focal point is located 1 mm to 3 mm below the surface of the shell plate; S34, summarizing the dynamically adjusted output power, welding speed and focus position to form welding parameters, and controlling the operation of the laser processing device by the welding parameters to perform the main welding stage.

[0011] Optionally, the S4 specifically includes: S41. During the main welding stage, the molten pool observation system is started, and the molten pool observation system obtains molten pool image data through multi-angle and multi-spectral methods, and the molten pool image data includes the length, width, depth, shape boundary and flow characteristics of the molten pool surface; S42, the molten pool observation system performs image processing and analysis on the molten pool image data acquired in real time, extracts geometric characteristic parameters of the molten pool, and analyzes the flow characteristics of the molten pool. The flow characteristics of the molten pool include the velocity field and temperature field distribution of the molten metal flow in the molten pool; S43, integrating the processed molten pool geometric characteristic parameters and flow characteristics to generate molten pool morphology information.

[0012] Optionally, the molten pool morphology information includes molten pool size change curve parameters and shape stability parameters.

[0013] Optionally, the S5 specifically includes: S51, inputting the molten pool morphology information and the first prediction result outputted by the temperature-deformation prediction model at the corresponding moment into the molten pool deformation model, correcting and optimizing the first prediction result through the molten pool deformation model, recalculating the transient temperature field distribution and deformation trend diagram of the welding area, and obtaining a second prediction result; S52. According to the second prediction result, the welding parameters of the laser processing device are dynamically adjusted for a second time, and the operation of the laser processing device is controlled by the welding parameters adjusted for the second time until the welding is completed to obtain a nuclear reactor shell.

[0014] A laser processing device for a nuclear reactor shell, using the above-mentioned laser processing method for a nuclear reactor shell, comprises: A laser processing mechanism, the laser processing mechanism comprising a fixture for clamping the shell plate and a laser generator for welding the shell plate, and also comprising an adjustment component capable of adjusting welding parameters; A temperature sensing assembly, the temperature sensing assembly comprising a plurality of infrared temperature sensors, the infrared temperature sensors being arranged in a matrix along the direction of the weld, the infrared temperature sensors being spaced 5 mm to 10 mm apart, and being used to monitor the temperature distribution of the welding area in real time and obtain temperature information of welding heat input and thermal gradient data; A control system, whose input end is electrically connected to the temperature sensor assembly and whose output end is electrically connected to the laser processing mechanism, for dynamically adjusting the welding parameters of the laser processing mechanism; A molten pool observation system, the molten pool observation system includes a multispectral imaging device and a data processing unit. The multispectral imaging device is installed in the welding area and is used to capture the geometric shape and flow characteristics of the molten pool in real time. The data processing unit is electrically connected to the control system and is used to process the molten pool image data, extract the molten pool geometric feature parameters and flow characteristic parameters, and correct the first prediction result according to the molten pool morphology information to generate a second prediction result.

[0015] The present invention provides a laser processing device and a processing method for a nuclear reactor shell, which have the following beneficial effects: Compared with the prior art, the laser processing device and processing method of the nuclear reactor shell enhance the material's absorption efficiency of laser and improve the stability of welding by performing surface modification pretreatment on the shell plate to be welded. Subsequently, the temperature sensing component is used for real-time temperature monitoring and prediction model to predict deformation trend and stress distribution, discover potential problems in advance, and dynamically adjust welding parameters according to the prediction results, so as to make the welding process more accurate and reduce the occurrence of welding defects. The molten pool monitoring provides real-time information on the molten pool state to ensure the stability of the molten pool and the quality of the weld. Finally, by correcting the prediction model and adjusting the welding parameters again, the welding process is further optimized to ensure the quality consistency of the final product. Through the combination of pretreatment, real-time monitoring, prediction model and dynamic adjustment, the welding deformation and stress concentration are effectively controlled, the welding quality and structural strength are improved, and the strict requirements of the nuclear reactor shell for high reliability and high safety are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical contents disclosed by the present invention.

[0018] Figure 1 This is a schematic diagram of a process for preparing a positive electrode material for a sodium ion battery according to Example 1; Figure 2The second schematic diagram is a process flow diagram of the method for preparing the positive electrode material for a sodium ion battery of Example 1; Figure 3 The third schematic diagram is a process flow diagram of the method for preparing the positive electrode material of a sodium ion battery of Example 1. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. All other embodiments obtained by ordinary technicians in the field without making creative work based on the embodiments of the present invention shall fall within the scope of protection of the present invention.

[0020] Embodiment 1: See also Figures 1 to 3 The present invention provides a technical solution: a laser processing method for a nuclear reactor shell, comprising: S1. Performing surface modification pretreatment on the welding area of ​​the shell plate to be welded; Before welding begins, the surface of the plates to be welded of the nuclear reactor shell is modified and pretreated. The purpose of this step is to improve the surface properties of the welding area by physical or chemical methods, such as removing oxides, dirt and impurities, or forming a micro-scale structure on the surface through laser surface treatment. These measures can improve the material's absorption efficiency of laser energy, reduce laser reflection losses, and promote the formation of a molten pool, thereby improving welding quality and stability, laying a good foundation for the subsequent welding process.

[0021] S2. Performing initial welding on the pre-treated shell plate by a laser processing device. During the initial welding process, a temperature sensor component is used to monitor the temperature distribution of the welding area in real time to obtain temperature information of the welding area, and the temperature information is input into a preset temperature-deformation prediction model to predict the deformation trend and stress distribution, so as to obtain a first prediction result. In this step, a laser processing device is used to perform initial welding on the shell plate that has completed surface pretreatment. During the initial welding process, a temperature sensing component is used to monitor the temperature distribution of the welding area in real time to obtain accurate temperature information. These temperature data are input into a preset temperature-deformation prediction model. The model predicts the deformation trend and stress distribution that may occur during the welding process based on the thermal physical and mechanical properties of the material, and obtains a first prediction result. Through real-time temperature monitoring and prediction models, temperature anomalies and stress concentration areas that may occur during the welding process can be discovered in a timely manner.

[0022] S3. Based on the first prediction result obtained, dynamically adjust the welding parameters of the laser processing device for the first time to perform the main welding stage, wherein the welding parameters include adjusting the output power, welding speed and focal position of the laser beam; In this step, the welding parameters of the laser processing device are dynamically adjusted for the first time based on the first prediction result obtained. These welding parameters include the output power of the laser beam, welding speed and focal position. By reasonably adjusting these parameters, the input and distribution of laser energy can be optimized, the welding heat input can be controlled, the welding deformation and residual stress can be reduced, the molten pool can be stably formed, and the weld quality meets the requirements. The adjusted welding parameters enable the welding process to enter the main welding stage.

[0023] S4. During the main welding stage, the molten pool observation system monitors the geometric shape and flow characteristics of the molten pool during welding and generates molten pool shape information; In this step, during the main welding stage, the molten pool observation system is used to monitor the geometric shape and flow characteristics of the molten pool in real time during the welding process. The molten pool observation system captures the shape, size and flow of the molten pool through a high-resolution, high-speed imaging device. The molten pool morphology information obtained includes the width, depth, shape stability of the molten pool and the flow pattern within the molten pool, which reflects the dynamic characteristics of the welding process and the welding quality.

[0024] S5, continuously correcting the first prediction result according to the molten pool morphology information to obtain a second prediction result, and dynamically adjusting the welding parameters of the laser processing device for a second time according to the second prediction result until the welding is completed, thereby obtaining a nuclear reactor shell; In this step, the previous first prediction result is continuously corrected using the acquired molten pool morphology information to generate a more accurate second prediction result. Based on the second prediction result, the welding parameters of the laser processing device are dynamically adjusted for the second time, including further precise adjustment of the laser output power, welding speed and focal position. Through these adjustments, the energy input and distribution in the welding process are optimized to ensure that the molten pool morphology is stable and the weld quality meets the requirements. The welding parameters are continuously monitored and adjusted until the welding process is successfully completed, and finally the nuclear reactor shell is obtained.

[0025] The working principle of the present invention is as follows: the welding area of ​​the shell plate to be welded is subjected to surface modification pretreatment to form a microscale structure to enhance the absorption of laser energy. Then, the pretreated plate is initially welded using a laser processing device. During the initial welding process, the temperature distribution of the welding area is monitored in real time using a temperature sensing component, and the acquired temperature information is input into a preset temperature-deformation prediction model to predict the deformation trend and stress distribution to obtain a first prediction result. Based on the first prediction result, the welding parameters of the laser processing device are dynamically adjusted for the first time. The adjustment parameters include the output power of the laser beam, the welding speed and the focal position to perform a normal welding process. During the normal welding process, the geometric shape and flow characteristics of the molten pool are monitored by a molten pool observation system to generate molten pool morphology information. Finally, the first prediction result is corrected using the molten pool morphology information to obtain a second prediction result, and the welding parameters are dynamically adjusted for a second time according to the second prediction result until the welding is completed.

[0026] In this embodiment, S1 specifically includes: S11, cleaning the welding area of ​​the shell plate to be welded, wherein the cleaning process is to use a degreasing agent or an alkaline cleaning solution to remove grease and oxide scale on the surface; In this step, use a special degreasing agent or alkaline cleaning fluid to remove grease, lubricants and other organic pollutants on the welding surface. If these substances remain in the welding area, they may decompose at high temperatures and produce harmful gases or inclusions, affecting the welding quality. The use of a degreasing agent or alkaline cleaning fluid can effectively remove surface oxide scale and rust and improve the cleanliness of the metal surface.

[0027] S12, performing surface treatment of fine grinding and polishing on the cleaned welding area; In this step, fine grinding uses fine-grained sandpaper or abrasive tools to remove tiny scratches, unevenness and residual oxide layers on the welding surface and reduce the surface roughness. Then, through the polishing process, the smoothness and flatness of the welding area are further improved, and microscopic protrusions and depressions are eliminated. This surface treatment helps to reduce laser reflection losses during welding and improve the absorption rate of laser energy, thereby enhancing the formation and stability of the molten pool.

[0028] S13, spraying or electroplating the surface of the welding area after the surface treatment to form a uniform high-absorption coating in the welding area, wherein the material of the high-absorption coating includes black chromium or black nickel having a high absorption rate to laser; In this step, a uniform high-absorption coating is formed on the surface of the welding area that has been finely ground and polished by spraying or electroplating. The selected coating material is a metal or alloy with high laser absorption, such as black chromium or black nickel, which can significantly improve the welding area's absorption capacity for laser energy, reduce laser reflection, and enhance the absorption of laser energy on the material surface. The thickness and uniformity of the coating are precisely controlled to ensure that the laser absorption rate is maximized without affecting the performance of the substrate, which helps to improve welding efficiency, increase penetration, and improve welding quality. It is especially suitable for deep-penetration welding of thick plates.

[0029] S14, micro-scale structural processing of the weld area with a high absorptivity coating by pulsed laser; In this step, a pulsed laser is used to perform micro-scale structural processing on the welding area that has been coated with a high-absorption coating. The pulsed laser has the characteristics of high peak power and short pulse width, and can accurately engrave micro-nanoscale structures on the surface of the material, such as micro-grooves, micro-holes or micro-protrusions. By controlling laser parameters (such as pulse energy, repetition frequency, scanning speed and beam focus position), a specific microstructure array can be formed on the surface of the welding area. These micro-scale structures further enhance the surface's absorption capacity for lasers, increase the actual light-receiving area, and introduce an optical trap effect to reduce laser reflection and scattering. In addition, the micro-scale structure can also promote the formation and stabilization of the molten pool, improve the fluidity of the molten metal, and improve the quality and mechanical properties of the welded joint.

[0030] S15, coating an anti-oxidation film on the welding area where the micro-scale structure is formed; In this step, since the surface area of ​​the microstructure increases significantly, the exposed metal is more likely to react with oxygen in the air to form an oxide layer, resulting in a decrease in surface performance. An ultra-thin anti-oxidation film is coated on the surface by chemical or physical methods, such as using inert metals or organic protective agents. The anti-oxidation film needs to have good density and adhesion, and can be easily removed or not affect the welding quality during the subsequent laser welding process, ensuring that the microstructure is not oxidized or contaminated before welding, and maintaining its high absorption rate and surface performance.

[0031] In this embodiment, S14 specifically includes: S141, adjusting pulse laser processing parameters according to characteristic parameters and thickness parameters of the nuclear reactor shell; In this step, the processing parameters of the pulse laser are precisely adjusted according to the specific characteristic parameters (such as material, thermophysical properties, surface condition) and thickness parameters of the nuclear reactor shell. The key processing parameters of the pulse laser include pulse energy, pulse width, repetition frequency, beam quality, spot size and focal position. For example, for thicker shell plates, it is necessary to select appropriate pulse energy and pulse width to ensure that the laser forms an effective nonlinear optical effect on the material surface and achieves the required processing depth and microstructure size. By adjusting the repetition frequency and scanning speed, the cumulative thermal effect of the laser on the material surface can be controlled to avoid material damage caused by excessive heating. Accurate parameter adjustment can ensure the formation of high-quality microscale structures on the surface of the welding area.

[0032] S142, presetting the shape of the microscale structure, wherein the predefined shape of the microscale structure includes periodically arranged micro-grooves or micro-protrusions arranged in a regular two-dimensional array; In this step, commonly used microscale structural shapes include periodically arranged micro-grooves (such as grooves, slits) or micro-protrusions (such as columnar, conical structures). These microstructures can optimize the surface absorption rate and scattering characteristics of lasers by adjusting their shapes, sizes and arrangements. The preset arrangement is a regular two-dimensional array, that is, they are arranged in an orderly manner on a plane according to a fixed spacing and direction. This regular structure helps to form a uniform molten pool and stable molten metal flow during the welding process, reducing the occurrence of welding defects.

[0033] S143, performing micro-scale structural processing on the welding area coated with the high-absorption coating according to the set pulse laser processing parameters and the preset shape of the micro-scale structure, and etching the preset micro-scale structure on the surface of the welding area by using the nonlinear optical effect of the laser; In this step, the high peak power and short pulse width of the pulsed laser are used to produce strong nonlinear optical effects on the surface of the material, such as multiphoton absorption and plasma-induced ablation, which can accurately etch micro-nanoscale structural features on the surface of the material without affecting the performance of the substrate. The laser beam moves according to the preset scanning path and speed, processing periodically arranged micro-grooves or micro-protrusions point by point or line by line to form a regular two-dimensional array.

[0034] In this embodiment, S2 specifically includes: S21, fixing the shell plate with the micro-scale structure on the welding platform of the laser processing device through a clamping device, and ensuring that the laser beam can accurately act on the welding area and the accuracy of the welding path through accurate positioning and fixing; S22. Arrange a temperature sensing assembly in the welding area, wherein the temperature sensing assembly includes a plurality of infrared temperature sensors, and the infrared temperature sensors are arranged in a matrix along the direction of the weld, and the spacing between adjacent infrared temperature sensors is 5 mm to 10 mm, so as to fully capture the temperature field in the welding area and obtain subtle thermal gradients and change information.

[0035] S23, setting initial welding parameters of the laser processing device; In this step, it should be noted that the initial welding parameters of the laser processing device are set according to the material properties, thickness and welding requirements of the shell plate. The initial welding parameters include laser output power, welding speed, laser spot diameter and focal position. For example, the laser output power can be set to 6 kW to 12 kW, the laser beam spot diameter to 0.5 mm to 2 mm, the welding speed to 0.2 m / min to 0.8 m / min, balancing the welding efficiency and quality, and the focal position is adjusted to an appropriate depth below the surface of the plate.

[0036] S24, starting the laser processing device to perform initial welding on the shell plate, the laser beam continuously moves along the weld direction, and the temperature sensing component monitors the temperature information of the welding area in real time, the temperature information including the molten pool temperature, the heat affected zone temperature, the welding heat input and the thermal gradient; In this step, it should be noted that the laser beam continuously moves along the weld direction according to the preset welding path, heats the welding area with high energy density to form a molten pool, and at the same time, the temperature sensing component monitors the temperature information of the welding area in real time, including the temperature of the molten pool, the temperature of the heat-affected zone, the welding heat input and the thermal gradient; It should be further explained that in the laser welding process of the nuclear reactor shell, the thermal gradient refers to the spatial rate of change of temperature in the welding area. The original intention of setting and monitoring the thermal gradient is to gain an in-depth understanding of the heat transfer inside the material during the welding process, as well as the thermal stress and thermal deformation caused thereby. By mastering the thermal gradient, the welding parameters can be controlled more accurately, the occurrence of welding defects can be prevented, and the welding quality can be improved. Each of the multiple infrared temperature sensors is a detection point, and each detection point obtains the temperature information of a specific position. The thermal gradient of the area can be calculated through the temperature difference between adjacent detection points in space and the distance between them.

[0037] S25, inputting the temperature information into a preset temperature-deformation prediction model, wherein the temperature-deformation prediction model is based on a finite element analysis method, combined with characteristic parameters and thickness parameters of the shell plate material and welding process parameters, to simulate and calculate the thermal deformation and stress distribution caused by temperature changes during the welding process; In this step, it should be noted that the temperature-deformation prediction model is based on the finite element analysis method, which comprehensively considers the material characteristic parameters (such as thermal conductivity, specific heat capacity, thermal expansion coefficient and elastic modulus) of the shell plate, thickness parameters and actual welding process parameters. By simulating the temperature field, stress field and strain field, the thermal deformation and stress distribution caused by temperature changes during the welding process are predicted. The simulation calculation can reveal the thermal stress concentration points and deformation trends inside the welding area.

[0038] S26. A first prediction result is obtained through simulation calculation of a temperature-deformation prediction model. The first prediction result includes a transient temperature field distribution and a deformation trend diagram of the welding area. The transient temperature field distribution is used to display the changes in temperature in time and space during the welding process, and the deformation trend diagram is used to display the thermal stress and displacement distribution caused by the temperature increase. This can determine whether the initial welding parameters need to be adjusted and identify potential welding defect risks.

[0039] In this embodiment, the characteristic parameters of the shell plate material include thermophysical performance parameters and mechanical performance parameters. The thermophysical performance parameters include thermal conductivity, specific heat capacity and thermal expansion coefficient, and the mechanical performance parameters include Young's modulus, Poisson's ratio and yield strength.

[0040] In this embodiment, S3 specifically includes: S31, analyzing the transient temperature field distribution and deformation trend diagram obtained from the temperature-deformation prediction model, identifying the locations in the deformation trend diagram where the temperature distribution is uneven, the thermal stress is concentrated, or the locations exceed the preset deformation threshold, and marking them as abnormal areas; In this step, it should be noted that the transient temperature field distribution and deformation trend diagram of the welding area obtained by the temperature-deformation prediction model are deeply analyzed to identify the locations where the temperature distribution is uneven, the thermal stress is concentrated, or the deformation exceeds the preset threshold in the welding area. These abnormal areas may cause welding defects such as cracks, deformation or structural stress concentration, affecting the welding quality and structural strength. By accurately locating and marking these abnormal areas in the deformation trend diagram, a clear goal and basis are provided for the subsequent welding parameter adjustment, ensuring the stability and reliability of the welding process.

[0041] S32, analyzing the abnormal area to obtain abnormal information, wherein the abnormal information includes a peak value, an area of ​​the abnormal area, and a corresponding abnormal type, and dynamically adjusting the laser beam output power and welding speed of the laser processing device based on the obtained abnormal information; In this step, it should be noted that the abnormal information includes the temperature or stress peak value of the abnormal area, which shows the severity of the abnormality, the area of ​​the abnormal area, the scope of the abnormal impact, and the corresponding abnormal type, to determine whether it is caused by too high or too low temperature or stress concentration factors. Based on these abnormal information, the control system makes the first dynamic adjustment to the welding parameters of the laser processing device, mainly adjusting the output power and welding speed of the laser beam. Specifically, if the temperature in the abnormal area is too high or the stress is too large, it is necessary to reduce the laser power or increase the welding speed to reduce the heat input. On the contrary, if the temperature in the abnormal area is too low or the penetration is insufficient, it is necessary to increase the laser power or reduce the welding speed, aiming to optimize the welding heat input, eliminate the abnormality, and ensure the welding quality. The control system is a known technology and is only cited here without further elaboration.

[0042] S33. According to the material thickness and melting depth requirements, the focal position of the laser beam is dynamically adjusted. If the melting depth needs to be increased, the focal position is adjusted downward, that is, the focal point is located 3 mm to 6 mm below the surface of the shell plate; if the melting depth needs to be reduced, the focal position is adjusted upward, that is, the focal point is located 1 mm to 3 mm below the surface of the shell plate; S34, summarizing the dynamically adjusted output power, welding speed and focal position to form welding parameters, controlling the operation of the laser processing device by the welding parameters to carry out the main welding stage, inputting the optimized welding parameters into the control system of the laser processing device, operating according to the new parameters, and entering the main welding stage.

[0043] In this embodiment, S4 specifically includes: S41. During the main welding stage, the molten pool observation system is started, and the molten pool observation system obtains molten pool image data through multi-angle and multi-spectral methods, and the molten pool image data includes the length, width, depth, shape boundary and flow characteristics of the molten pool surface; In this step, it should be noted that the molten pool observation system uses multi-angle and multi-spectral imaging technology to obtain image data of the molten pool from different viewing angles and spectral ranges. Multi-angle imaging enables the capture of the three-dimensional geometric shape of the molten pool, including length, width and depth, so as to fully understand the shape and size of the molten pool. At the same time, multi-spectral imaging (such as visible light, near-infrared and thermal infrared) can obtain image information of the molten pool at different wavelengths, reflecting the temperature distribution and material properties of the molten pool surface. The acquired image data not only includes the shape boundary of the molten pool, but also includes the flow characteristics of the molten pool surface, such as the flow direction of the molten metal, surface fluctuations and eddies.

[0044] S42, the molten pool observation system performs image processing and analysis on the molten pool image data acquired in real time, extracts geometric characteristic parameters of the molten pool, and analyzes the flow characteristics of the molten pool. The flow characteristics of the molten pool include the velocity field and temperature field distribution of the molten metal flow in the molten pool; In this step, it should be noted that the geometric characteristic parameters of the molten pool, including the length, width, depth and shape boundary of the molten pool, are extracted by using image processing algorithms, such as filtering, edge detection and morphological operations. The velocity field and temperature field distribution of the molten metal flow in the molten pool are calculated by analyzing the brightness, temperature distribution and texture changes on the molten pool surface and combining multispectral data. The flow velocity, flow direction and temperature gradient of the molten metal in the molten pool can be quantitatively measured by using technologies such as particle image velocimetry and infrared thermal imaging. The flow characteristics of the molten pool reflect the thermal convection and heat transfer process of the molten metal, which has an important influence on the formation and performance of the weld. It can identify possible anomalies in the molten pool, such as turbulence, vortex or uneven cooling, and adjust the welding parameters in time to ensure the welding quality.

[0045] S43. Integrate the processed molten pool geometric characteristic parameters and flow characteristics to generate molten pool morphology information. The molten pool morphology information comprehensively reflects the state of the molten pool during the welding process. By establishing the molten pool morphology information, the evolution law of the molten pool during the welding process can be intuitively understood, and the stability of the welding process and the quality of weld formation can be evaluated.

[0046] In this embodiment, the molten pool morphology information includes molten pool size change curve parameters and shape stability parameters. By continuously monitoring the length, width and depth size parameters of the molten pool, the molten pool size change curve with time or welding process, these curves reflect the dynamic change trend of the molten pool size during the welding process, and can capture the fluctuation of the molten pool size. The shape stability parameter can evaluate the stability of the molten pool shape during the welding process, and is quantified by calculating the molten pool shape factor and the shape fluctuation amplitude index. The shape stability of the molten pool directly affects the forming quality and mechanical properties of the weld.

[0047] In this embodiment, S5 specifically includes: S51, inputting the molten pool morphology information and the first prediction result outputted by the temperature-deformation prediction model at the corresponding moment into the molten pool deformation model, correcting and optimizing the first prediction result through the molten pool deformation model, recalculating the transient temperature field distribution and deformation trend diagram of the welding area, and obtaining a second prediction result; In this step, it should be noted that the molten pool morphology information obtained from the molten pool observation system and the first prediction result output by the temperature-deformation prediction model at the corresponding moment are input into the molten pool deformation model. The molten pool deformation model is based on the finite element analysis method, and can combine the actual molten pool geometry and flow characteristics to simulate the welding process more accurately. The first prediction result is corrected and optimized through the molten pool deformation model. By using the real-time molten pool morphology information, the model can correct the part of the original prediction that does not match the actual situation, update the material's thermal physical performance parameters and boundary conditions, compensate for the temperature field and stress field deviations caused by changes in the molten pool morphology, and recalculate the transient temperature field distribution and deformation trend diagram of the welding area to obtain a more accurate second prediction result. The second prediction result provides a more realistic temperature distribution, deformation trend and stress distribution in the welding area, and can more accurately reflect the heat conduction, thermal stress and structural deformation in the welding process.

[0048] S52, according to the second prediction result, dynamically adjusting the welding parameters of the laser processing device for a second time, controlling the operation of the laser processing device by the second dynamically adjusted welding parameters, until the welding is completed and the nuclear reactor shell is obtained, inputting the adjusted welding parameters into the control system of the laser processing device, and adjusting the laser output power, welding speed and focus position parameters in real time during the welding process by a closed-loop control method, so as to ensure a smooth transition of the welding process and the accuracy of parameter adjustment; The dynamic adjustment is a single-line logic, that is, during the second dynamic adjustment, the first dynamic adjustment stops.

[0049] Embodiment 2: The present invention also provides a laser processing device for a nuclear reactor shell, which adopts the laser processing method for a nuclear reactor shell as described above, comprising: A laser processing mechanism, the laser processing mechanism comprising a fixture for clamping the shell plate and a laser generator for welding the shell plate, and also comprising an adjustment component capable of adjusting welding parameters; A temperature sensing assembly, the temperature sensing assembly comprising a plurality of infrared temperature sensors, the infrared temperature sensors being arranged in a matrix along the direction of the weld, the infrared temperature sensors being spaced 5 mm to 10 mm apart, and being used to monitor the temperature distribution of the welding area in real time and obtain temperature information of welding heat input and thermal gradient data; A control system, whose input end is electrically connected to the temperature sensor assembly and whose output end is electrically connected to the laser processing mechanism, for dynamically adjusting the welding parameters of the laser processing mechanism; A molten pool observation system, the molten pool observation system comprising a multispectral imaging device and a data processing unit, the multispectral imaging device is installed in the welding area (it may also be a high-speed camera) and is used to capture the geometric shape and flow characteristics of the molten pool in real time, the data processing unit is electrically connected to the control system, and is used to process the molten pool image data, extract the molten pool geometric characteristic parameters and flow characteristic parameters, and correct the first prediction result according to the molten pool morphology information to generate a second prediction result; The temperature sensing component monitors the temperature information of the welding area in real time and transmits the collected data to the control system. The control system receives the temperature data and inputs it into the temperature-deformation prediction model for calculation. The control system calls the temperature-deformation prediction model and uses the real-time temperature data to calculate the transient temperature field and deformation trend of the welding area to generate a first prediction result. The control system dynamically adjusts the welding parameters of the laser processing mechanism according to the calculation results of the prediction model. The multispectral imaging device monitors the morphology and flow characteristics of the molten pool in real time during the main welding stage, and can generate molten pool morphology information for multiple multispectral cameras installed in the welding area. The data processing unit analyzes the molten pool image data and extracts key parameters. The molten pool morphology information is sent to the control system through the data transmission interface. The control system inputs the molten pool morphology information and the first prediction result into the molten pool deformation model. The molten pool deformation model corrects and optimizes the first prediction result to generate a second prediction result. The second prediction result of the molten pool deformation model is fed back to the control system. The control system further adjusts the welding parameters of the laser processing mechanism according to the second prediction result.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A laser processing method for a nuclear reactor shell, characterized in that: include: S1. Performing surface modification pretreatment on the welding area of ​​the shell plate to be welded; S2. Performing initial welding on the pre-treated shell plate by a laser processing device. During the initial welding process, a temperature sensor component is used to monitor the temperature distribution of the welding area in real time to obtain temperature information of the welding area, and the temperature information is input into a preset temperature-deformation prediction model to predict the deformation trend and stress distribution, so as to obtain a first prediction result. S3. Based on the first prediction result obtained, dynamically adjust the welding parameters of the laser processing device for the first time to perform the main welding stage, wherein the welding parameters include adjusting the output power, welding speed and focal position of the laser beam; S4. During the main welding stage, the molten pool observation system monitors the geometric shape and flow characteristics of the molten pool during welding and generates molten pool shape information; S5. Continuously correct the first prediction result through the molten pool morphology information to obtain a second prediction result, and dynamically adjust the welding parameters of the laser processing device for a second time through the second prediction result until the welding is completed to obtain a nuclear reactor shell.

2. A laser processing method for a nuclear reactor shell according to claim 1, characterized in that: The S1 specifically includes: S11, cleaning the welding area of ​​the shell plate to be welded, wherein the cleaning process is to use a degreasing agent or an alkaline cleaning solution to remove grease and oxide scale on the surface; S12, performing surface treatment of fine grinding and polishing on the cleaned welding area; S13, spraying or electroplating the surface of the welding area after the surface treatment to form a uniform high-absorption coating in the welding area, wherein the material of the high-absorption coating includes black chromium or black nickel having a high absorption rate to laser; S14, micro-scale structural processing of the weld area with a high absorptivity coating by pulsed laser; S15. Coating an anti-oxidation film on the welding area where the micro-scale structure is formed.

3. The laser processing method for a nuclear reactor shell according to claim 2, characterized in that: The S14 specifically includes: S141, adjusting pulse laser processing parameters according to characteristic parameters and thickness parameters of the nuclear reactor shell; S142, presetting the shape of the microscale structure, wherein the predefined shape of the microscale structure includes periodically arranged micro-grooves or micro-protrusions, and the arrangement is a regular two-dimensional array; S143. According to the set pulse laser processing parameters and the preset shape of the micro-scale structure, the welding area coated with the high absorption rate coating is subjected to micro-scale structural processing, and the preset micro-scale structure is etched on the surface of the welding area by using the nonlinear optical effect of the laser.

4. The laser processing method for a nuclear reactor shell according to claim 2, characterized in that: The S2 specifically includes: S21, fixing the shell plate with the micro-scale structure on the welding platform of the laser processing device through a clamping device; S22, arranging a temperature sensing assembly in the welding area, wherein the temperature sensing assembly includes a plurality of infrared temperature sensors, and the infrared temperature sensors are arranged in a matrix along the welding seam direction, and the spacing between adjacent infrared temperature sensors is 5 mm to 10 mm; S23, setting initial welding parameters of the laser processing device; S24, starting the laser processing device to perform initial welding on the shell plate, the laser beam continuously moves along the weld direction, and the temperature sensing component monitors the temperature information of the welding area in real time, the temperature information including the molten pool temperature, the heat affected zone temperature, the welding heat input and the thermal gradient; S25, inputting the temperature information into a preset temperature-deformation prediction model, wherein the temperature-deformation prediction model is based on a finite element analysis method, combined with characteristic parameters and thickness parameters of the shell plate material and welding process parameters, to simulate and calculate the thermal deformation and stress distribution caused by temperature changes during the welding process; S26. Obtain a first prediction result through simulation calculation of the temperature-deformation prediction model, wherein the first prediction result includes a transient temperature field distribution and a deformation trend diagram of the welding area.

5. The laser processing method for a nuclear reactor shell according to claim 4, characterized in that: The characteristic parameters of the shell plate material include thermophysical performance parameters and mechanical performance parameters. The thermophysical performance parameters include thermal conductivity, specific heat capacity and thermal expansion coefficient, and the mechanical performance parameters include Young's modulus, Poisson's ratio and yield strength.

6. The laser processing method for a nuclear reactor shell according to claim 4, characterized in that: The S3 specifically includes: S31, analyzing the transient temperature field distribution and deformation trend diagram obtained from the temperature-deformation prediction model, identifying the locations in the deformation trend diagram where the temperature distribution is uneven, the thermal stress is concentrated, or the locations exceed the preset deformation threshold, and marking them as abnormal areas; S32, analyzing the abnormal area to obtain abnormal information, wherein the abnormal information includes a peak value, an area of ​​the abnormal area, and a corresponding abnormal type, and dynamically adjusting the laser beam output power and welding speed of the laser processing device based on the obtained abnormal information; S33. According to the material thickness and melting depth requirements, the focal position of the laser beam is dynamically adjusted. If the melting depth needs to be increased, the focal position is adjusted downward, that is, the focal point is located 3 mm to 6 mm below the surface of the shell plate; if the melting depth needs to be reduced, the focal position is adjusted upward, that is, the focal point is located 1 mm to 3 mm below the surface of the shell plate; S34, summarizing the dynamically adjusted output power, welding speed and focal position to form welding parameters, and controlling the operation of the laser processing device by the welding parameters to perform the main welding stage.

7. The laser processing method for a nuclear reactor shell according to claim 1, characterized in that: The S4 specifically includes: S41. During the main welding stage, the molten pool observation system is started, and the molten pool observation system obtains molten pool image data through multi-angle and multi-spectral methods, and the molten pool image data includes the length, width, depth, shape boundary and flow characteristics of the molten pool surface; S42, the molten pool observation system performs image processing and analysis on the molten pool image data acquired in real time, extracts geometric characteristic parameters of the molten pool, and analyzes the flow characteristics of the molten pool. The flow characteristics of the molten pool include the velocity field and temperature field distribution of the molten metal flow in the molten pool; S43, integrating the processed molten pool geometric characteristic parameters and flow characteristics to generate molten pool morphology information.

8. The laser processing method for a nuclear reactor shell according to claim 7, characterized in that: The molten pool morphology information includes molten pool size change curve parameters and shape stability parameters.

9. The laser processing method for a nuclear reactor shell according to claim 1, characterized in that: The S5 specifically includes: S51, inputting the molten pool morphology information and the first prediction result outputted by the temperature-deformation prediction model at the corresponding moment into the molten pool deformation model, correcting and optimizing the first prediction result through the molten pool deformation model, recalculating the transient temperature field distribution and deformation trend diagram of the welding area, and obtaining a second prediction result; S52. According to the second prediction result, the welding parameters of the laser processing device are dynamically adjusted for a second time, and the operation of the laser processing device is controlled by the welding parameters adjusted for the second time until the welding is completed to obtain a nuclear reactor shell.

10. A laser processing device for a nuclear reactor shell, characterized in that: A laser processing method for a nuclear reactor shell according to any one of claims 1 to 9, comprising: A laser processing mechanism, the laser processing mechanism comprising a fixture for clamping the shell plate and a laser generator for welding the shell plate, and also comprising an adjustment component capable of adjusting welding parameters; A temperature sensing assembly, the temperature sensing assembly comprising a plurality of infrared temperature sensors, the infrared temperature sensors being arranged in a matrix along the direction of the weld, the infrared temperature sensors being spaced 5 mm to 10 mm apart, and being used to monitor the temperature distribution of the welding area in real time and obtain temperature information of welding heat input and thermal gradient data; A control system, whose input end is electrically connected to the temperature sensor assembly and whose output end is electrically connected to the laser processing mechanism, for dynamically adjusting the welding parameters of the laser processing mechanism; A molten pool observation system, the molten pool observation system includes a multispectral imaging device and a data processing unit. The multispectral imaging device is installed in the welding area and is used to capture the geometric shape and flow characteristics of the molten pool in real time. The data processing unit is electrically connected to the control system and is used to process the molten pool image data, extract the molten pool geometric feature parameters and flow characteristic parameters, and correct the first prediction result according to the molten pool morphology information to generate a second prediction result.

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