A method and material for complex remanufacturing of a desulfurization circulating pump impeller

Abstract

The present application relates to the technical field of complex shape remanufacturing, in particular to a complex shape remanufacturing method and material for a desulfurization circulating pump impeller, the complex shape remanufacturing method comprising constructing a multi-modal damage intelligent mapping; synchronously preparing plasma activation and micro-texture; performing energy field coupling cladding repair; performing stress field balance shot peening strengthening; implementing gradient coating self-propagating synthesis; performing thermal-mechanical coupling precision shaping; performing micro-gap pressure infiltration sealing; and performing multi-physical field service simulation verification. The present application can significantly prolong the service cycle of key components, comprehensively enhance the comprehensive performance of anti-cavitation and erosion resistance, establish a digital twin closed loop of damage diagnosis, repair optimization and life prediction, and simultaneously realize life cycle cost control and resource saving. Not only can the present application repair failed components, but also can it rebuild a sustainable operation system.

Description

Technical Field

[0001] This invention relates to the field of remanufacturing technology, specifically to a remanufacturing method and material for desulfurization circulating pump impellers. Background Technology

[0002] The desulfurization circulating pump impeller is a core flow-through component of a wet desulfurization system, operating in an acidic slurry environment with a pH of 2-5.5, and typically rotating at 800-1500 rpm. Its main failure mode is a triple coupled damage of acid corrosion, solid erosion, and cavitation, especially the blade inlet edge and the rear cover plate area, which face millimeter-level / year-level deep erosion.

[0003] However, traditional remanufacturing technologies generally suffer from systemic defects: neglect of thermal matching leads to through-cracks between the repair layer and the substrate; interface bonding relies on mechanical anchoring and cannot withstand high-frequency vibration loads; subsurface micropore defects become hidden channels for corrosion diffusion; and empirical repair strategies deviate significantly from actual service life. These inherent bottlenecks make it difficult for remanufactured impellers to achieve the expected overall performance and reliability. Summary of the Invention

[0004] The purpose of this invention is to provide a method and material for the remanufacturing of desulfurization circulating pump impellers, which improves the impeller's repair capability and service life.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] First aspect of the invention:

[0007] This invention proposes a method for remanufacturing a desulfurization circulating pump impeller, the method comprising constructing a multimodal damage intelligent mapping and simultaneously preparing plasma activation and microtexture;

[0008] Energy field coupled cladding repair and stress field balanced shot peening strengthening were carried out; gradient coating self-propagating synthesis was implemented, as well as thermomechanical coupled precision shaping and micro-gap pressure melt infiltration sealing were performed; and finally, multi-physics field service simulation was conducted for verification.

[0009] Optionally, the implementation process for constructing the multimodal damage intelligent mapping is as follows:

[0010] A four-dimensional damage model of the blade surface was constructed using laser scanning point cloud data and ultrasonic residual stress field detection results.

[0011] Based on the extracted impeller basic material parameters, the thermal deformation compensation amount is preset during 3D reconstruction.

[0012] Optionally, the process for preparing plasma activation and microtexture is as follows:

[0013] When the damage core region located in the step of constructing multimodal damage intelligent mapping is scanned on the surface using a pulsed plasma beam, an argon-nitrogen mixed gas is simultaneously introduced to induce in-situ nitriding.

[0014] By controlling the overlap rate of the beam spots to form a periodic array of micro-protrusions, mechanical locking anchors are provided for the cladding layer.

[0015] Optionally, the implementation process for energy field coupling cladding repair is as follows:

[0016] For the microtextured region generated in the plasma activation and microtexturing steps, a dual heat source synergistic system is activated: high-frequency induction preheating reduces cladding thermal shock, while a coaxial laser beam irradiates the induction heating region.

[0017] The laser spot is precisely matched with the micro-protrusion array, and the energy concentration effect at the top of the protrusion is used to achieve directional grain growth and control the cooling gradient of the molten pool.

[0018] Optionally, the implementation process of the stress field balance shot peening strengthening is as follows:

[0019] Based on the measured thickness distribution of the cladding layer in the energy field coupling cladding repair step, a regional variable intensity shot peening strategy is adopted: ceramic shot is used in the thickness abrupt change zone, and glass shot is used in the smooth zone.

[0020] The shot peening trajectory is automatically planned based on the residual stress distribution map in the process of constructing the intelligent multimodal damage mapping, so that the stress difference is <100MPa.

[0021] Optionally, the implementation process of gradient coating self-propagating synthesis is as follows:

[0022] After the activated surface is treated in the stress field balance shot peening strengthening step, a transition layer, a wear-resistant layer, and a sealing layer are alternately sprayed with NiAl powder, and the lattice distortion energy generated in the stress field balance shot peening strengthening step is used to trigger a self-propagating reaction.

[0023] When preheated to 650°C, according to the material melting point of 60% in the multimodal damage intelligent mapping step, NiAl undergoes an exothermic reaction, which increases the interfacial diffusion rate and forms a functionally graded coating.

[0024] Optionally, the implementation process for performing thermomechanical coupling precision shaping is as follows:

[0025] The five-axis machine tool calls the initial model in the step of constructing the intelligent mapping of multimodal damage and the coating thickness distribution map in the step of implementing gradient coating self-propagation synthesis, and sets differentiated cutting parameters on the working surface of the blade: ultrasonic vibration-assisted cutting is used in the coating area, and cryogenic liquid nitrogen cooling cutting is used in the substrate area;

[0026] The feed rate is dynamically adjusted based on the local hardness value.

[0027] Optionally, the implementation process of the micro-gap pressure melt-infiltration seal is as follows:

[0028] Using the subsurface micropores exposed after processing in the thermomechanical coupling precision shaping step, an isostatic pressure of 150 MPa is applied in a vacuum chamber, and a low-melting-point alloy Sn60Pb40 is introduced simultaneously.

[0029] During the pressure holding phase, the alloy melt penetrates along the dislocation channels generated in the stress field equilibrium shot peening strengthening step.

[0030] Optionally, the implementation process for multiphysics service simulation verification is as follows:

[0031] By integrating the damage model in the step of constructing a multimodal damage intelligent mapping, the coating property parameters in the step of implementing gradient coating self-propagation synthesis, and the sealing structure data in the step of micro-gap pressure melting and sealing, a three-phase fluid-solid coupling model is constructed.

[0032] The boundary conditions include: the erosion resistance threshold of the cladding layer in the energy field coupling cladding repair step and the critical point of the coating phase transition in the gradient coating self-propagating synthesis step;

[0033] The processing settings for the thermomechanical coupling precision shaping step were verified through iterative calculations.

[0034] This invention also proposes a remanufacturing material for desulfurization circulating pump impellers, applied to the aforementioned remanufacturing method for desulfurization circulating pump impellers, wherein the remanufacturing material comprises:

[0035] The substrate repair layer is one of FeCrMoNbRE nickel-based alloy or iron-based composite powder, and is used in the energy field coupling cladding repair step.

[0036] Stress-regulating material, comprising a thickness abrupt change region material and a smooth region material, wherein the thickness abrupt change region material is Si3N4 silicon nitride ceramic pellets and the smooth region material is zirconium-based amorphous alloy pellets, is used in the stress field balancing shot peening strengthening step.

[0037] The functionally graded coating further includes a transition layer, a wear-resistant layer, and a sealing layer. The transition layer is one of NiCrMo-7 alloy or FeCrSiB composite 30% TiC alloy powder. The wear-resistant layer is one of Cr2O3 composite 20% Al2O3 nanopowder or 10Co4Cr composite 5% nanodiamond. The sealing layer is one of PTFE microcapsule doped nickel-based alloy or PyC pyrolytic carbon coating. These are used to implement the self-propagating synthesis step of the gradient coating.

[0038] A sealing and infiltrating material, wherein the sealing and infiltrating material is one of SnAgCu-Ti composite solder or Cu-SiC composite material, is used in the micro-gap pressure infiltrating and sealing step.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] The remanufacturing method of this invention forms a complete digital closed-loop system by establishing a technology chain that includes intelligent damage mapping, constructing interface topology, collaborative energy field repair, building a functional gradient reinforcement layer, achieving closed-loop sealing of micro-defects, and quantitative prediction of service life. The core breakthrough lies in the deep integration of dynamic thermal deformation compensation, multi-effect synchronous surface modification, interface metallurgical reaction control, and precise sealing of micropores. This fundamentally changes the extensive repair logic of traditional welding and machining, giving remanufactured impellers improved performance, significantly extending the service life of key components, comprehensively enhancing anti-cavitation and anti-erosion performance, establishing a digital twin closed loop of damage diagnosis, repair optimization, and service life prediction, and achieving full life cycle cost control and resource conservation. It not only repairs failed components but also rebuilds a sustainable operating system. Attached Figure Description

[0041] Figure 1 This is a schematic flowchart of the remanufacturing method for desulfurization circulating pump impellers according to the present invention. Detailed Implementation

[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all 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.

[0043] Example 1, please refer to Figure 1 This invention proposes a method for remanufacturing a desulfurization circulating pump impeller, the method comprising the following steps:

[0044] S1. Construct a multimodal damage intelligent mapping. S2. Simultaneously prepare plasma activation and microtexture. S3. Perform energy field coupled cladding repair. S4. Perform stress field balanced shot peening strengthening. S5. Implement gradient coating self-propagating synthesis. S6. Perform thermomechanical coupled precision shaping. S7. Perform micro-gap pressure infiltration sealing. S8. Perform multiphysics service simulation verification.

[0045] It should also be noted that the implementation process of step S1 is as follows:

[0046] A four-dimensional damage model of the blade surface was constructed using laser scanning point cloud data and ultrasonic residual stress field detection results. Based on the extracted impeller base material parameters, thermal deformation compensation was preset during three-dimensional reconstruction.

[0047] By integrating four-dimensional modeling technology with geometric dimensions and residual stress fields, the limitations of traditional detection, which can only obtain single morphological data, are overcome, and dynamic compensation for thermal deformation is achieved. This step fundamentally avoids the risk of cracking of the repair layer caused by thermal stress mismatch and provides a precise physical field reference for subsequent processes.

[0048] It should also be noted that the implementation process of step S2 is as follows:

[0049] When the damaged core region located in step S1 is scanned with a pulsed plasma beam, an argon-nitrogen mixed gas is simultaneously introduced to induce in-situ nitriding. The beam spot overlap rate is controlled to form a periodic micro-protrusion array, providing mechanical locking anchors for the cladding layer.

[0050] By integrating surface activation, microtexture construction, and in-situ nitriding into a single process, the problem of weak interfacial bonding caused by traditional step-by-step processing is solved. The resulting composite structure significantly improves the mechanical bonding force of the cladding layer and eliminates coating peeling failure under high-frequency vibration conditions.

[0051] It should also be noted that the implementation process of step S3 is as follows:

[0052] For the microtextured region generated in step S2, a dual-heat source synergistic system is activated: high-frequency induction preheating reduces the thermal shock of the cladding process, while a coaxial laser beam irradiates the induction heating area. The laser spot is precisely matched with the micro-protrusion array, utilizing the energy concentration effect at the top of the protrusions to achieve directional grain growth and control the cooling gradient of the molten pool.

[0053] The dual-heat-source synergistic mechanism precisely regulates the heat input distribution, completely suppressing the grain coarsening defects of single-heat-source repair. The directional grain growth technology makes the repair layer structure uniform and dense, providing defect-free matrix support for functional gradient coatings.

[0054] It should also be noted that the implementation process of step S4 is as follows:

[0055] Based on the measured thickness distribution of the cladding layer in step S3, a regional variable intensity shot peening strategy is adopted: ceramic shot is used in the abrupt thickness change zone, and glass shot is used in the gradual thickness change zone. The shot peening trajectory is automatically planned according to the residual stress distribution map in step S1, so that the stress difference is <100MPa.

[0056] Based on the partitioned strengthening strategy of thickness abrupt change zone and residual stress field, the stress concentration phenomenon at geometric discontinuity in traditional uniform shot peening is solved. Through the synergistic control of rigid-elastic dual materials, the stress difference of the entire impeller is compressed to within the safe threshold.

[0057] It should also be noted that the implementation process of step S5 is as follows:

[0058] On the activated surface after step S4, a transition layer, a wear-resistant layer, and a sealing layer are alternately sprayed with NiAl powder. The lattice distortion generated in step S4 triggers a self-propagating reaction. When preheated to 650°C, based on the material melting point of 60% in step S1, NiAl undergoes an exothermic reaction, increasing the interfacial diffusivity and forming a functionally graded coating.

[0059] The self-propagating exothermic reaction drives interfacial atomic diffusion, solving the inherent defects of traditional thermal spray coatings such as high porosity and low bonding strength. The functional gradient structure achieves a continuous transition between hardness and toughness, enabling the coating to have both corrosion resistance and impact resistance under extreme working conditions.

[0060] It should also be noted that the implementation process of step S6 is as follows:

[0061] The five-axis machine tool calls the initial model from step S1 and the coating thickness distribution map from step S5, and sets differentiated cutting parameters on the blade working surface: ultrasonic vibration-assisted cutting is used in the coating area, and cryogenic liquid nitrogen cooling cutting is used in the substrate area. The feed rate is dynamically adjusted according to the local hardness value.

[0062] The hardness-adaptive composite cutting process solves the bottleneck in hard coating processing, avoids secondary damage such as edge chipping and micro-cracks caused by traditional machining, and ensures blade profile accuracy and surface integrity simultaneously, restoring the original hydraulic performance design.

[0063] It should also be noted that the implementation process of step S7 is as follows:

[0064] Using the subsurface micropores exposed after processing in step S6, an isostatic pressure of 150 MPa is applied within the vacuum chamber, while a low-melting-point alloy Sn60Pb40 is simultaneously introduced. During the pressure holding phase, the alloy melt penetrates along the dislocation channels generated in step S4.

[0065] High-pressure melting infiltration technology achieves full-area sealing of subsurface micropores, eradicating the hidden corrosion channels neglected by traditional processes. The sealing phase forms a metallurgical bond with the substrate, establishing an internal anti-corrosion barrier that penetrates the repair layer.

[0066] It should also be noted that the implementation process of step S8 is as follows:

[0067] A three-phase fluid-structure interaction model was constructed by integrating the damage model from step S1, the coating properties from step S5, and the sealing structure data from step S7. Boundary conditions were set, including the erosion resistance threshold of the cladding layer from step S3 and the critical phase transformation point of the coating from step S5. The processing settings from step S6 were verified through iterative calculations.

[0068] Based on actual physical parameters, the fluid-structure interaction model overturns the empirical life prediction mode. By quantifying the correlation of key parameters, it can accurately predict the service behavior of remanufactured impellers.

[0069] This invention also proposes a remanufacturing material for desulfurization circulating pump impellers, applied to the aforementioned remanufacturing method for desulfurization circulating pump impellers. The specific steps of the remanufacturing method are described in the preceding text and will not be repeated here. The remanufacturing material includes:

[0070] The substrate repair layer is one of FeCrMoNbRE nickel-based alloy or iron-based composite powder, and is used for energy field coupling cladding in step S3.

[0071] The stress-regulating material includes a thickness abrupt change region material and a smooth region material. The thickness abrupt change region material is Si3N4 silicon nitride ceramic pellets, and the smooth region material is zirconium-based amorphous alloy pellets, which are used for shot peening in step S4.

[0072] The functionally graded coating further includes a transition layer, a wear-resistant layer, and a sealing layer. The transition layer is one of NiCrMo-7 alloy or FeCrSiB composite 30% TiC alloy powder. The wear-resistant layer is one of Cr2O3 composite 20% Al2O3 nanopowder or 10Co4Cr composite 5% nanodiamond. The sealing layer is one of PTFE microcapsule doped nickel-based alloy or PyC pyrolytic carbon coating, used for self-propagating synthesis in step S5.

[0073] A sealing and infiltrating material, wherein the sealing and infiltrating material is one of SnAgCu-Ti composite solder or Cu-SiC composite material, is used for micro-gap sealing in step S7.

[0074] This embodiment is designed with a customized material system for the special working conditions of acid corrosion and solid erosion of desulfurization circulating pumps. Through the functional synergistic design of the substrate repair layer, gradient coating and melt-infiltration sealing layer, it achieves integrated protection of corrosion prevention, wear resistance and crack resistance throughout the entire life cycle. At the same time, the material is compatible with the remanufacturing process, which fundamentally solves the problem of early failure caused by the incompatibility between traditional materials and repair processes.

[0075] Example 2, in practical applications, a method for remanufacturing a desulfurization circulating pump impeller specifically includes the following steps:

[0076] S1. Constructing a multimodal damage intelligent mapping:

[0077] Using laser scanning point cloud data (accuracy ±0.05mm) and ultrasonic residual stress field detection results, a four-dimensional damage model (X / Y / Z coordinates + stress value) of the blade surface was constructed.

[0078] Based on the extracted impeller basic material parameters (such as the coefficient of thermal expansion α = 13.5 × 10⁻), 6 / K), during 3D reconstruction, the preset thermal deformation compensation amount ΔL=α·Δt·L, where Δt is dynamically adjusted according to the cladding temperature.

[0079] By constructing a multimodal intelligent damage mapping, the problem of traditional detection being able to only obtain geometric size errors and ignoring the coupling effect of residual stress field and thermal deformation, which leads to a high risk of secondary cracking of the impeller after repair, is solved. By constructing a four-dimensional damage model that includes stress distribution and pre-setting thermal deformation compensation amount (ΔL=α·Δt·L), the thermal distortion accumulation of subsequent high-temperature cladding is eliminated.

[0080] S2. Simultaneous preparation of plasma activation and microtexture:

[0081] In the damage core area located in step S1, the region with a cavitation pit depth ≥1.5mm, when scanning the surface with a pulsed plasma beam of 8kW power / 200Hz frequency, an argon-nitrogen mixed gas with a flow rate ratio of 4:1 is simultaneously introduced to induce in-situ nitriding.

[0082] By controlling the beam overlap rate to 65%, a periodic micro-protrusion array is formed with a height of 50±5μm and a spacing of 300μm, providing mechanical locking anchor points for the cladding layer.

[0083] By simultaneously preparing plasma activation and microtexturing, the problem of conventional sandblasting roughening being unable to form effective anchor points in deep pits is solved, and nitriding treatment requires a separate process. In-situ nitriding simultaneously generates a CrN hardened layer (HV1100) + micro-protrusion array, which improves the cladding bonding strength by 60% (>85MPa).

[0084] S3. Perform energy field coupling cladding repair:

[0085] For the microtextured region generated in step S2, a dual heat source collaborative system is activated: high-frequency induction preheating at 300℃±10℃ reduces the thermal shock of cladding, while a coaxial 3.2kW laser beam irradiates the induction heating region.

[0086] The laser spot is precisely matched with the micro-protrusion array, and the energy concentration effect at the top of the protrusion is used to achieve directional grain growth. The cooling gradient of the molten pool is controlled to be ≤150℃ / s. According to step S1, the thermal conductivity coefficient of the material is λ=15W / m·K.

[0087] It should also be noted that this embodiment also provides a cladding repair material, applied to the energy field coupling cladding repair in step S3, including:

[0088] The FeCrMoNbRE nickel-based alloy for acidic conditions has the following composition: Cr 18-22wt%, Mo 15-18wt%, Nb 3.5wt%.

[0089] WC35wt%-FeCrNiMo iron-based composite powder for high solids content applications, with WC particle size of 45-75μm.

[0090] By using energy field coupling cladding repair, the problem of uncontrollable heat input in single-heat-source cladding, which leads to grain coarsening in the heat-affected zone of the substrate, is solved. By using dual-heat-source synergy (induction preheating + laser cladding), the cooling gradient is compressed to ≤150℃ / s, and the proportion of oriented columnar crystals is >90%.

[0091] S4. Perform stress field balancing shot peening:

[0092] Based on the measured thickness distribution of the cladding layer in step S3, in practical applications, the leading edge of the blade is 2.3 mm thick and the rear cover plate is 1.1 mm thick. A regional variable intensity shot peening strategy is adopted: in the thickness abrupt change zone with a gradient > 1 mm / 10 mm, Φ0.8 mm ceramic shot is used for impact with an impact intensity of 0.45 mmA, and in the smooth zone, Φ0.3 mm glass shot is used with an impact intensity of 0.2 mmA.

[0093] The shot peening trajectory is automatically planned based on the residual stress distribution diagram in step S1, so that the stress difference is <100MPa.

[0094] It should also be noted that a stress-regulating material, applied to the stress field balancing shot peening strengthening in step S4, includes:

[0095] The thickness abrupt change region is treated with Φ0.8mm Si3N4 silicon nitride ceramic pellets, with an elastic modulus of 310GPa.

[0096] In the smooth zone, use Φ0.3mm zirconium-based amorphous alloy pellets with an elastic deformation of >8%.

[0097] By strengthening shot peening through stress field balance, the stress concentration induced by uniform shot peening in the abrupt thickness change zone is solved. By controlling the shot peening intensity in different zones based on the thickness distribution of the cladding layer and the residual stress field, the stress difference is compressed to <100MPa.

[0098] S5. Implement gradient coating self-propagating synthesis:

[0099] After the activated surface is treated in step S4, a transition layer, a wear-resistant layer, and a sealing layer are alternately sprayed with NiAl powder, and the lattice distortion energy generated in step S4 is used to trigger a self-propagating reaction.

[0100] When preheated to 650℃, according to step S1 where the material's melting point is 60%, NiAl undergoes an exothermic reaction, increasing the interfacial diffusion rate of the WC layer by 3 times, ΔH = -280 kJ / mol, forming a functionally graded coating, HV 0.3 :1200→800.

[0101] It should also be noted that this embodiment also provides a gradient coating material, applied to the self-propagating synthesis in step S5, including:

[0102] Transition layer materials: NiCrMo-7 alloy for acidic conditions, and FeCrSiB+30vol%TiC composite powder for high solid content conditions.

[0103] Wear-resistant layer materials: Cr2O3 + 20wt%Al2O3 nanocomposite powder for acidic conditions, and WC-10Co4Cr + 5wt% nanodiamond for high solid content conditions.

[0104] Sealing layer materials: PTFE microcapsules doped with nickel-based alloy for acidic conditions, with a particle size of 5μm; PyC pyrolytic carbon coating for high solids content conditions.

[0105] By using gradient coating self-propagating synthesis, the problem of micropores (porosity > 2%) at the interface of traditional thermal spray WC coatings is solved. The interface diffusion is enhanced by inducing NiAl exothermic reaction (ΔH = -280 kJ / mol), and the porosity is reduced to 0.3%.

[0106] S6. Perform precise thermomechanical coupling shaping:

[0107] The five-axis machine tool calls the initial model of step S1 and the coating thickness distribution map of step S5, and sets differentiated cutting parameters on the working surface of the blade: for coating area HV>1000, ultrasonic vibration assisted cutting with amplitude 15μm / frequency 20kHz is used, and for substrate area, cryogenic liquid nitrogen cooling cutting is used.

[0108] The feed rate is dynamically adjusted based on the local hardness value V: V_cut = 0.2·(1000 / HV) 0.3 mm / rev, baseline value HV=800.

[0109] Precision shaping via thermomechanical coupling solves the problem of edge chipping caused by ordinary cutting of hard coatings (HV>1000) by using hardness-adaptive cutting (V_cut=0.2·(1000 / HV)). 0.3 Achieve zero-crack reshaping of the coating.

[0110] S7. Perform micro-gap pressure melt infiltration sealing:

[0111] Using the subsurface micropores with a diameter of <10μm exposed after processing in step S6, apply an isostatic pressure of 150MPa in a vacuum chamber and simultaneously introduce a low-melting-point alloy Sn60Pb40 with a melting point of 183℃.

[0112] During the pressure holding phase, the alloy melt penetrates along the dislocation channels generated in step S4, with the penetration depth as follows:

[0113] d=√(2kP·t / η).

[0114] Where k is calculated to be 0.8 based on the microtexture spacing in step S2, and η is the melt viscosity, specifically η = 2.5 mPa·s.

[0115] It should also be noted that this embodiment also provides a melt-infiltrating sealing material, applied to the micro-gap pressure melt-infiltrating in step S7, including:

[0116] SnAgCu-Ti composite solder for acidic conditions, with a Ti content of 4wt%.

[0117] Cu-30vol%SiC composite material for high solids content applications.

[0118] By using micro-gap pressure melt infiltration sealing, the exposed subsurface micropores (diameter <10μm) become corrosion channels, and the high pressure melt infiltration sealing rate of 150MPa is >99.5% (penetration depth d=√(2kP·t / η)).

[0119] S8. Conduct multiphysics service simulation verification:

[0120] By integrating the damage model from step S1, the coating properties from step S5, and the sealing structure data from step S7, a three-phase fluid-structure coupling model is constructed.

[0121] The boundary conditions are set as follows: Step S3: erosion resistance threshold of the cladding layer: slurry solid phase concentration 30%; Step S5: critical point of phase transformation of the coating: temperature 50℃.

[0122] The correlation equation between the blade inlet angle and cavitation intensity was verified by iterative calculation in step S6: σ_c = 0.02·β 2 +0.35.

[0123] Where β is the entrance angle.

[0124] Through multiphysics service simulation verification, the problem of the inability of empirical repair to predict the critical point of cavitation failure was solved, using σ_c=0.02β. 2 The +0.35 equation quantitatively correlates the inlet angle with cavitation intensity, and the service life prediction error is <5%.

[0125] In summary, through the above steps, the present invention provides performance enhancement to the remanufactured impeller of the desulfurization circulating pump, significantly extends the service life of key components, comprehensively enhances the combined performance of anti-cavitation and anti-erosion, establishes a digital twin closed loop of damage diagnosis, repair optimization, and life prediction, and achieves full life cycle cost control and resource conservation. It not only repairs failed components, but also rebuilds a sustainable operating system.

[0126] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0127] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for remanufacturing a desulfurization circulating pump impeller, characterized in that, The complex remanufacturing method includes constructing a multimodal damage intelligent map and simultaneously preparing plasma activation and microtexture; Energy field coupling cladding repair and stress field balancing shot peening strengthening are carried out. The gradient coating self-propagating synthesis was implemented, along with thermomechanical coupling precision shaping and micro-gap pressure melting sealing; finally, the results were verified through multi-physics service simulation. The implementation process for constructing a multimodal damage intelligent mapping is as follows: using laser scanning point cloud data and ultrasonic residual stress field detection results, a four-dimensional damage model of the blade surface is constructed; based on the extracted impeller base material parameters, a thermal deformation compensation amount is preset during three-dimensional reconstruction. The implementation process for preparing plasma activation and microtexture is as follows: when the damage core area located in the step of constructing multimodal damage intelligent mapping is scanned on the surface using a pulsed plasma beam, an argon-nitrogen mixed gas is simultaneously introduced to induce in-situ nitriding; the beam spot overlap rate is controlled to form a periodic micro-protrusion array, providing mechanical locking anchor points for the cladding layer; The implementation process of energy field coupling cladding repair is as follows: For the microtextured region generated in the steps of preparing plasma activation and microtexturing, a dual heat source synergistic system is started: high-frequency induction preheating reduces the thermal shock of cladding, while a coaxial laser beam irradiates the induction heating area; the laser spot is precisely matched with the micro-protrusion array, and the energy concentration effect at the top of the protrusion is used to achieve directional grain growth and control the cooling gradient of the molten pool.

2. The method for remanufacturing a desulfurization circulating pump impeller according to claim 1, characterized in that, The implementation process of stress field balance shot peening is as follows: Based on the measured thickness distribution of the cladding layer in the energy field coupling cladding repair step, a regional variable intensity shot peening strategy is adopted: ceramic shot is used in the thickness abrupt change zone, and glass shot is used in the smooth zone. The shot peening trajectory is automatically planned based on the residual stress distribution map in the process of constructing the intelligent multimodal damage mapping, so that the stress difference is <100MPa.

3. The method for remanufacturing a desulfurization circulating pump impeller according to claim 2, characterized in that, The implementation process for gradient coating self-propagating synthesis is as follows: After the activated surface is treated in the stress field balance shot peening strengthening step, a transition layer, a wear-resistant layer, and a sealing layer are alternately sprayed with NiAl powder, and the lattice distortion energy generated in the stress field balance shot peening strengthening step is used to trigger a self-propagating reaction. When preheated to 650°C, according to the material melting point of 60% in the multimodal damage intelligent mapping step, NiAl undergoes an exothermic reaction, which increases the interfacial diffusion rate and forms a functionally graded coating.

4. The method for remanufacturing a desulfurization circulating pump impeller according to claim 3, characterized in that, The implementation process for thermomechanical coupling precision shaping is as follows: The five-axis machine tool calls the initial model in the step of constructing the intelligent mapping of multimodal damage and the coating thickness distribution map in the step of implementing gradient coating self-propagation synthesis, and sets differentiated cutting parameters on the working surface of the blade: ultrasonic vibration-assisted cutting is used in the coating area, and cryogenic liquid nitrogen cooling cutting is used in the substrate area; The feed rate is dynamically adjusted based on the local hardness value.

5. The method for remanufacturing a desulfurization circulating pump impeller according to claim 4, characterized in that, The implementation process of the micro-gap pressure melt infiltration seal is as follows: Using the subsurface micropores exposed after processing in the thermomechanical coupling precision shaping step, an isostatic pressure of 150 MPa is applied in a vacuum chamber, and a low-melting-point alloy Sn60Pb40 is introduced simultaneously. During the pressure holding phase, the alloy melt penetrates along the dislocation channels generated in the stress field equilibrium shot peening strengthening step.

6. The method for remanufacturing a desulfurization circulating pump impeller according to claim 5, characterized in that, The implementation process for multiphysics service simulation verification is as follows: By integrating the damage model in the step of constructing a multimodal damage intelligent mapping, the coating property parameters in the step of implementing gradient coating self-propagation synthesis, and the sealing structure data in the step of micro-gap pressure melting and sealing, a three-phase fluid-solid coupling model is constructed. The boundary conditions include: the erosion resistance threshold of the cladding layer in the energy field coupling cladding repair step and the critical point of the coating phase transition in the gradient coating self-propagating synthesis step; The processing settings for the thermomechanical coupling precision shaping step were verified through iterative calculations.

7. A remanufacturing material for a desulfurization circulating pump impeller, applied to a remanufacturing method for a desulfurization circulating pump impeller according to any one of claims 1 to 6, characterized in that, The remanufacturing material includes: The substrate repair layer is one of FeCrMoNbRE nickel-based alloy or iron-based composite powder, and is used in the energy field coupling cladding repair step. Stress-regulating material, comprising a thickness abrupt change region material and a smooth region material, wherein the thickness abrupt change region material is Si3N4 silicon nitride ceramic pellets and the smooth region material is zirconium-based amorphous alloy pellets, is used in the stress field balancing shot peening strengthening step. The functionally graded coating further includes a transition layer, a wear-resistant layer, and a sealing layer. The transition layer is one of NiCrMo-7 alloy or FeCrSiB composite 30% TiC alloy powder. The wear-resistant layer is one of Cr2O3 composite 20% Al2O3 nanopowder or 10Co4Cr composite 5% nanodiamond. The sealing layer is one of PTFE microcapsule doped nickel-based alloy or PyC pyrolytic carbon coating. These are used to implement the self-propagating synthesis step of the gradient coating. A sealing and infiltrating material, wherein the sealing and infiltrating material is one of SnAgCu-Ti composite solder or Cu-SiC composite material, is used in the micro-gap pressure infiltrating and sealing step.

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