Process for removing adsorbates from a high-temperature turbine blade coating surface

Abstract

This invention discloses a process for removing adsorbents from the surface of aluminized turbine blades at high temperatures, belonging to the field of surface treatment technology for aero-engine turbine blades. The process includes: using urea-plastic sand as the blowing medium, and performing sandblasting treatment on the aluminized turbine blades according to preset injection angle, preset injection distance, preset sandblasting pressure, and preset sandblasting time; cleaning residual sand and ultrasonically cleaning the blades after sandblasting; when the blades are hollow, conducting film pore flow tests before sandblasting and after ultrasonic cleaning, and performing high-temperature sand removal treatment when the flow rate decrease exceeds a preset difference. This application effectively removes adsorbents from the surface of the aluminized layer and reduces the risk of residual sand clogging the film pores.

Description

Technical Field

[0001] This application relates to the field of surface treatment technology for aero-engine turbine blades, specifically to a process for removing adsorbents from the surface of high-temperature turbine blade diffusion layers. Background Technology

[0002] High-temperature turbine blades operate under extreme temperatures, pressures, and combustion gases. To improve their oxidation resistance, corrosion resistance, and service life, an aluminized layer is typically formed on the blade surface. This aluminized layer is relatively thin, and after the blade enters service, adsorbates, oxides, or thermal scale can easily accumulate on its surface. These deposits can cause fluorescence adsorption or background interference during fluorescent inspection, affecting the identification of defects such as cracks and reducing the accuracy of blade defect detection.

[0003] In existing technologies, engine parts are typically cleaned using methods such as hydrocarbon cleaning and aqueous ultrasonic cleaning. Hydrocarbon cleaning is mainly used to remove oil seals or small amounts of oil, while aqueous ultrasonic cleaning is mainly used to remove contaminants such as oil, carbon deposits, rust, or oxide scale. However, for aluminized turbine blades after service, the adsorbents on the aluminized layer surface differ from ordinary oil, carbon, or rust. Their bonding with the aluminized layer surface is more complex, making it difficult to remove them completely using conventional cleaning methods. Even after multiple cleanings, the blades may still exhibit fluorescent adsorption, failing to meet the requirements for subsequent fluorescent inspections. To enhance the cleaning effect, acid-base solution cleaning or corundum abrasive blowing can be used to treat the blade surface. However, the aluminized layer on the surface of high-temperature turbine blades is relatively thin, and acid-base solutions or hard abrasive blowing can easily cause excessive removal of the aluminized layer, affecting blade size, blade profile, and the integrity of the aluminized layer. For hollow turbine blades with film cooling holes, abrasive may also enter the blade cavity or film cooling holes during the blowing process, causing blockage of the film cooling holes, affecting the cooling airflow performance of the blade, and consequently affecting the reliability of the blade in subsequent use.

[0004] Therefore, there is an urgent need to provide a process for removing adsorbents from the surface of the aluminized layer of high-temperature turbine blades, which can effectively remove adsorbents from the surface of the aluminized layer, meet the requirements of fluorescence inspection, and reduce the impact on the thickness of the aluminized layer, blade size, and blade shape. Summary of the Invention

[0005] This application provides a process for removing adsorbents from the surface of the aluminized turbine blade diffusion layer, in order to solve the technical problem that existing cleaning methods are difficult to effectively remove adsorbents from the surface of the aluminized turbine blade diffusion layer and easily affect the fluorescence inspection results.

[0006] According to one aspect of this application, a process for removing adsorbates from the surface of a high-temperature turbine blade diffusion layer is provided, comprising the following steps: S100 uses urea plastic sand as the blowing medium to blow sand onto the aluminized turbine blades according to preset process parameters in order to remove adsorbents on the surface of the aluminized layer of the aluminized turbine blades. The preset process parameters include preset injection angle, preset injection distance, preset blowing pressure and preset blowing time. S200 is used to clean residual sand from the aluminized turbine blades after sandblasting to remove the urea plastic sand remaining on the surface of the aluminized turbine blades. S300 is used for ultrasonic cleaning of aluminized turbine blades after residual sand removal. When the aluminized turbine blade to be treated is a hollow blade, a film pore flow test is performed on the hollow blade before S100 and after S300 respectively; when the decrease in the film pore flow test value after S300 relative to the film pore flow test value before S100 exceeds a preset difference, the hollow blade is subjected to high-temperature desanding treatment. High-temperature sand removal treatment includes: placing the hollow blades in a heating chamber for heating to vaporize and / or pulverize the urea plastic sand that has entered the inner cavity of the hollow blades; and using compressed air to blow away the pulverized residue in the inner cavity of the hollow blades. S400 is used to perform fluorescent inspection on aluminized turbine blades after ultrasonic cleaning.

[0007] Optionally, after high-temperature sand removal treatment, the hollow blades are subjected to another film pore flow test. If the decrease in the film pore flow rate test value compared to the previous film pore flow rate test value in S100 still exceeds the preset difference, the high-temperature desanding treatment and film pore flow rate test are repeated. When the air film orifice flow rate test value is qualified, proceed to S400.

[0008] Optionally, the preset process parameters are determined through the following steps: S110, Determine the preset spray angle; S120, under the preset injection angle, a gas phase high-energy jet simulation model is established based on the surface structure of the aluminized turbine blade to be treated, and the surface roughness distribution and surface stress distribution of the aluminized turbine blade under multiple candidate injection distances are simulated using the gas phase high-energy jet simulation model, and the preset injection distance is determined based on the surface roughness distribution and surface stress distribution. S130, under the conditions of preset injection angle and preset injection distance, set multiple candidate sand blowing pressure values ​​and multiple candidate sand blowing time values, and use the candidate sand blowing pressure values ​​and candidate sand blowing time values ​​as test factors to conduct urea plastic sand blowing orthogonal process test on aluminized turbine blades; based on the adsorbent removal effect, fluorescence inspection results, size inspection results and diffusion layer thickness inspection results after the orthogonal process test, determine the preset sand blowing pressure and preset sand blowing time.

[0009] Optionally, in step S110, the preset spray angle is 45°±20°.

[0010] Optionally, in S130, the orthogonal process test of urea-plastic sand blowing on aluminized turbine blades includes: Multiple candidate sand blowing pressure values ​​and multiple candidate sand blowing time values ​​are set, and the candidate sand blowing pressure values ​​and candidate sand blowing time values ​​are combined to obtain multiple orthogonal experimental groups; In each orthogonal test group, the type of urea plastic sand, the preset spray distance and the preset spray angle were kept consistent, and the test blades were treated with urea plastic sand blowing according to the candidate blowing pressure value and candidate blowing time value in the corresponding orthogonal test group.

[0011] Optionally, candidate blowing pressure values ​​include 0.15MPa, 0.2MPa and 0.25MPa, and candidate blowing time values ​​include 10s, 20s, 30s, 40s, 60s and 90s.

[0012] Optionally, before S100, the aluminized turbine blades are subjected to aqueous ultrasonic cleaning and fluorescent inspection. When the aluminized turbine blade does not exhibit fluorescence adsorption due to surface adsorbates after ultrasonic cleaning with water-based agent, the aluminized turbine blade is determined to be a blade that does not require sandblasting treatment. If the aluminized turbine blade still exhibits fluorescence adsorption due to surface adsorbates after ultrasonic cleaning with water-based agent, the aluminized turbine blade is designated as the aluminized turbine blade to be treated, and S100 is executed.

[0013] Optionally, the determination of preset process parameters also includes verifying the damage margin of preset sandblasting pressure and preset sandblasting time after S130. Damage margin verification includes: using urea plastic sand as the blowing medium, and performing control blowing treatment on the test blades according to the preset injection angle, preset injection distance and preset blowing pressure. The blowing time of the control blowing treatment is the product of the preset blowing time and the preset extension multiple, and the preset extension multiple is greater than 1. When the test blade after sandblasting treatment meets the requirements of continuous and intact seepage layer, no cracks, no peeling, and seepage layer removal amount not exceeding the preset seepage layer removal amount threshold, the preset sandblasting pressure and preset sandblasting time are determined as the process parameters that pass the damage margin verification.

[0014] Optionally, when the aluminized turbine blade to be treated is a hollow blade, a wax seal is used before S100 to prevent urea plastic sand from entering the inner cavity of the hollow blade. Wax sealing protection methods include: Use high-temperature resistant aluminum foil tape to seal the vent holes on the surface of the hollow blades and leave wax injection holes; Preheat the sealed hollow blades; Molten wax is poured into the inner cavity of the hollow blade through the wax injection hole; After the molten wax poured into the inner cavity of the hollow blade cools and solidifies, the hollow blade is then subjected to S100. After S100 and before S300, the hollow blades are immersed in hot water to melt and flow out the wax inside the hollow blades.

[0015] Optionally, when the aluminized turbine blade to be treated is a hollow blade, a differential pressure protection method is used before S100 to prevent urea plastic sand from entering the inner cavity of the hollow blade. The differential pressure protection method includes: installing the aluminized turbine blade to be treated on a ventilated blade sandblasting fixture, and introducing compressed air into the inner cavity of the hollow blade through the ventilated blade sandblasting fixture, so that the compressed air is discharged outward along the air film holes of the hollow blade; the pressure of the compressed air is greater than the preset sandblasting pressure of the urea plastic sand.

[0016] In summary, this application includes at least one of the following beneficial technical effects: This solution uses urea-plastic abrasive as the blowing medium and performs sandblasting treatment on the aluminized turbine blades according to preset injection angle, injection distance, blowing pressure, and blowing time. Since urea-plastic abrasive causes less impact damage to the aluminized layer compared to hard abrasives such as corundum, it can remove adsorbed substances from the surface of the aluminized layer of the turbine blade while minimizing the impact on the layer thickness, blade size, and blade profile. For hollow blades with film bleaching orifices, this application conducts film bleaching orifice flow tests before sandblasting and after ultrasonic cleaning, and determines whether urea-plastic abrasive has entered the inner cavity based on the flow rate decrease after sandblasting. To mitigate the risk of clogging the air film pores, when the flow rate decreases beyond a preset threshold, the hollow blades are placed in a heating chamber for heating. After being heated to 400℃, most of the urea plastic sand vaporizes, with the remaining portion easily pulverized. Furthermore, the urea plastic sand can be burned into ash by open flame. This ensures that even if plastic sand enters the hollow blade cavity during the removal of adsorbents from the blade surface, it can be removed through heating or burned into ash during use, preventing pore clogging. This approach ensures effective removal of adsorbents from the permeation layer while reducing the risk of pore clogging in the hollow blades, guaranteeing the reliability of subsequent fluorescence inspection and use.

[0017] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. A further detailed description of this application will be provided below with reference to the figures. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart of the process for removing adsorbents from the surface of the high-temperature turbine blade diffusion layer in this application. Detailed Implementation

[0019] The embodiments of this application are described in detail below with reference to the accompanying drawings; however, this application may be implemented in a variety of different ways as defined and covered below.

[0020] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0021] A process for removing adsorbates from the surface of a permeable layer on high-temperature turbine blades includes the following steps: S100 uses urea plastic sand as the blowing medium to blow sand onto the aluminized turbine blades according to preset process parameters in order to remove adsorbents on the surface of the aluminized layer of the aluminized turbine blades. The preset process parameters include preset injection angle, preset injection distance, preset blowing pressure and preset blowing time. S200 is used to clean residual sand from the aluminized turbine blades after sandblasting to remove the urea plastic sand remaining on the surface of the aluminized turbine blades. S300 is used for ultrasonic cleaning of aluminized turbine blades after residual sand removal. When the aluminized turbine blade to be treated is a hollow blade, a film pore flow test is performed on the hollow blade before S100 and after S300 respectively; when the decrease in the film pore flow test value after S300 relative to the film pore flow test value before S100 exceeds a preset difference, the hollow blade is subjected to high-temperature desanding treatment. High-temperature sand removal treatment includes: placing the hollow blades in a heating chamber for heating to vaporize and / or pulverize the urea plastic sand that has entered the inner cavity of the hollow blades; and using compressed air to blow away the pulverized residue in the inner cavity of the hollow blades. S400 is used to perform fluorescent inspection on aluminized turbine blades after ultrasonic cleaning.

[0022] In S100, urea-plastic abrasive is used as the blowing medium. Compared to hard abrasives such as corundum abrasive, urea-plastic abrasive causes less impact damage to the aluminized layer, and can remove adsorbents from the surface of the aluminized layer while minimizing the impact on the thickness of the aluminized layer, blade size, and blade profile. In actual processing, the aluminized turbine blade to be treated is placed within the working area of ​​the blowing equipment, with the blowing nozzle facing the surface of the blade. Blowing is performed according to preset spray angle, preset spray distance, preset blowing pressure, and preset blowing time. During the blowing process, urea-plastic abrasive is sprayed onto the blade surface with the compressed airflow, removing adsorbents from the aluminized layer surface through flexible impact and friction, gradually restoring the blade surface to a suitable condition for subsequent inspection.

[0023] In S200, residual sand is removed from the aluminized turbine blades after sandblasting. This removal can be achieved through compressed air purging, gentle vibration, sand removal by tilting, or manual assistance. The aim is to remove urea plastic sand from the outer surface of the blade, blade corners, tenon transition areas, and other areas prone to sand buildup, preventing residual sand particles from entering the subsequent cleaning solution or affecting subsequent inspection results. For blades with complex curved surfaces or locally recessed structures, residual sand can be removed separately from the blade base, blade back, inlet edge, exhaust edge, and blade transition area to improve the completeness of residual sand removal.

[0024] In the S300, the aluminized turbine blades, after residual sand removal, undergo ultrasonic cleaning. Ultrasonic cleaning further removes fine sand particles, powdery residues, and loosened deposits from the blade surface. During cleaning, the blades are placed in a cleaning tank, allowing the cleaning solution to fully contact the blade surface, which is then cleaned through ultrasonic cavitation. After ultrasonic cleaning, the blades are removed, drained, and dried before proceeding to subsequent testing steps.

[0025] When the aluminized turbine blades to be treated are hollow blades, urea-plastic sand may enter the film blowing holes or the blade's internal cavity during the sandblasting process, as hollow blades typically have film blowing holes or internal cooling channels. Therefore, a film blowing hole flow rate test is performed on the hollow blades before S100 to obtain the flow rate value before sandblasting, and this value is used as a baseline. After S300, another film blowing hole flow rate test is performed on the hollow blades to obtain the flow rate values ​​after sandblasting and cleaning. By comparing the flow rate values ​​after S300 with those before S100, it can be determined whether the sandblasting and cleaning processes have caused a decrease in the flow capacity of the film blowing holes.

[0026] When the decrease in film pore flow rate after S300 compared to the film pore flow rate before S100 exceeds a preset difference, it indicates that urea plastic sand may have entered the hollow blade cavity, film pores, or cooling channels, affecting airflow. In this case, high-temperature desanding treatment is performed on the hollow blade. The preset difference can be determined based on the film pore flow rate acceptance standard, repair process requirements, or blade usage requirements for this type of hollow blade. During high-temperature desanding treatment, the hollow blade is placed in a heating chamber for heating, causing the urea plastic sand that has entered the hollow blade cavity to vaporize and / or pulverize. After heating, the urea plastic sand can vaporize or transform into an easily pulverized state, thereby reducing the risk of blockage in the blade cavity, film pores, or cooling channels. After heating, compressed air is used to purge the hollow blade cavity, allowing the pulverized residue to be discharged with the airflow, thus restoring the unobstructed flow of the hollow blade's film pores and internal cooling channels.

[0027] In S400, fluorescent inspection is performed on aluminized turbine blades after ultrasonic cleaning. After urea plastic sand blowing, residual sand removal, and ultrasonic cleaning, the adsorbents on the surface of the aluminized turbine blades are removed or reduced, and the fluorescent adsorption or background interference is reduced, thus facilitating the identification and judgment of defects such as cracks on the blade surface.

[0028] The above process enables the low-damage removal of adsorbates from the surface of the aluminized turbine blade's diffusion layer using urea plastic sand, and reduces surface residue through residual sand cleaning and ultrasonic cleaning. For hollow blades, the flow rate of the air film pores before and after sand blowing can be used to determine whether residual sand affects the flow of the air film pores. When the flow rate decrease exceeds a preset difference, the urea plastic sand that has entered the inner cavity can be removed by high-temperature sand removal and compressed air blowing, thus taking into account the adsorbate removal effect, diffusion layer protection effect, and air film pore flow performance of hollow blades.

[0029] In one embodiment, after the high-temperature desanding treatment, the hollow blade is subjected to a film pore flow test again; if the decrease in the film pore flow test value compared with the film pore flow test value before S100 still exceeds the preset difference, the high-temperature desanding treatment and film pore flow test are repeated; if the film pore flow test value is qualified, S400 is executed.

[0030] Specifically, since urea plastic sand may enter the hollow blade cavity during sand blowing and form local stagnation in the film venting holes or internal cooling channels, a single high-temperature desanding treatment may not completely eliminate the risk of residue. Therefore, it is necessary to conduct another film venting flow test to confirm the effectiveness of the high-temperature desanding treatment. When conducting the second film venting flow test, the hollow blade can be tested under the same conditions as before S100, ensuring that the film venting flow test values ​​after high-temperature desanding treatment are comparable to those before sand blowing. If the decrease in the film venting flow test value compared to the value before S100 still exceeds the preset difference, it indicates that there may still be urea plastic sand residue that has not been completely discharged in the hollow blade cavity, film venting holes, or cooling channels, or there may still be powdery residue that affects airflow. After repeating the high-temperature desanding treatment, another film venting flow test should be conducted to further assess the flow status of the hollow blade. By cycling through high-temperature desanding treatment, compressed air blowing, and film pore flow test, hollow blades can be prevented from directly entering subsequent testing or use stages before the film pore flow has recovered. This reduces the risk of film pore blockage, insufficient cooling airflow, or decreased blade reliability due to residual sand retention.

[0031] When the film cooling flow rate test result is satisfactory, it indicates that the film cooling pores and internal cooling channels of the hollow blade meet the flow requirements. This suggests that the urea plastic sand that entered the hollow blade cavity during the sandblasting process has been effectively removed, or its residual level no longer affects the airflow performance of the hollow blade. At this point, S400 is executed again to perform a fluorescent inspection on the ultrasonically cleaned aluminized turbine blade. This ensures that before the hollow blade undergoes fluorescent inspection, not only have the adsorbed substances on the surface of the aluminized layer been removed, but the film cooling flow rate is also within acceptable limits, thus balancing the reliability of surface inspection and the flow reliability of the hollow blade's cooling channels.

[0032] In one implementation, the preset process parameters are determined through the following steps: S110, Determine the preset spray angle; S120, under the preset injection angle, a gas phase high-energy jet simulation model is established based on the surface structure of the aluminized turbine blade to be treated, and the surface roughness distribution and surface stress distribution of the aluminized turbine blade under multiple candidate injection distances are simulated using the gas phase high-energy jet simulation model, and the preset injection distance is determined based on the surface roughness distribution and surface stress distribution. S130, under the conditions of preset injection angle and preset injection distance, set multiple candidate sand blowing pressure values ​​and multiple candidate sand blowing time values, and use the candidate sand blowing pressure values ​​and candidate sand blowing time values ​​as test factors to conduct urea plastic sand blowing orthogonal process test on aluminized turbine blades; based on the adsorbent removal effect, fluorescence inspection results, size inspection results and diffusion layer thickness inspection results after the orthogonal process test, determine the preset sand blowing pressure and preset sand blowing time.

[0033] Specifically, due to differences in the profile structure, adsorbent adhesion degree, adsorbent layer thickness, and film pore structure of different aluminized turbine blades, directly using fixed sandblasting parameters may result in insufficient adsorbent removal or excessive impact on the adsorbent layer. Therefore, in this embodiment, before formally performing sandblasting treatment on the aluminized turbine blades to be treated, preset injection angle, preset injection distance, preset sandblasting pressure, and preset sandblasting time suitable for this type of blade are first determined.

[0034] In step S110, the preset spray angle is first determined. The preset spray angle is used to limit the relative angle between the spray direction of the sandblasting nozzle and the surface of the blade to be treated, so that the urea plastic sand can effectively act on the area of ​​the blade to be cleaned. The preset spray angle can be determined according to the sandblasting process requirements, the arrangement direction of the blade surface to be treated, and the operating space of the sandblasting nozzle.

[0035] In S120, a gas-phase high-energy jet simulation model is established at a preset injection angle. Based on the surface structure of the aluminized turbine blade to be treated, this model simulates the process of urea plastic sand being injected onto the blade surface under the influence of airflow. After simulations at multiple candidate injection distances, the surface roughness distribution and surface stress distribution corresponding to each distance are obtained. The surface roughness distribution reflects the degree of cleaning and smoothing of the blade surface at different injection distances; the surface stress distribution reflects the local intensity of the impact of the urea plastic sand on the blade surface. If the injection distance is too large, the energy of the urea plastic sand acting on the blade surface may be insufficient, resulting in poor adsorbent removal; if the injection distance is too small, the impact intensity of the urea plastic sand on the blade surface may be too high, increasing the risk of damage to the permeation layer. Therefore, this embodiment comprehensively determines the preset injection distance based on the surface roughness distribution and surface stress distribution, ensuring that the preset injection distance can balance the adsorbent removal effect and the permeation layer protection requirements.

[0036] In S130, under the predetermined preset injection angle and preset injection distance, the preset blowing pressure and preset blowing time are further determined. The blowing pressure affects the injection speed and impact intensity of the urea plastic sand, while the blowing time affects the duration of the urea plastic sand's effect on the blade surface. Too low a blowing pressure or too short a blowing time may result in insufficient removal of adsorbates from the surface of the aluminized layer; too high a blowing pressure or too long a blowing time may lead to increased loss of the aluminized layer thickness, and even affect the blade size, blade shape, or the integrity of the aluminized layer. Therefore, this embodiment uses candidate blowing pressure values ​​and candidate blowing time values ​​as experimental factors in an orthogonal process experiment for urea plastic sand blowing. After the orthogonal process experiment is completed, the test blades are inspected for adsorbate removal effectiveness, fluorescence, size, and aluminized layer thickness. The adsorbent removal effect check is used to determine whether the adsorbents on the blade surface have been effectively removed; the fluorescence check is used to determine whether fluorescent adsorption phenomena that affect defect identification still exist on the blade after sandblasting; the size check is used to determine whether the sandblasting treatment has an adverse effect on the blade's shape, leaf shape, or the size of key parts; and the aluminized layer thickness check is used to determine whether the sandblasting treatment has caused excessive removal of the aluminized layer. The treatment effect corresponding to each candidate sandblasting pressure value and candidate sandblasting time value is comprehensively evaluated based on the results of these multiple checks, thereby determining the preset sandblasting pressure and preset sandblasting time.

[0037] After determining the preset process parameters through S110 to S130, the urea plastic sand blowing treatment in S100 no longer relies on simple experience settings, but is determined based on the simulation results of the injection angle and injection distance, as well as the test results of pressure and time. This allows the urea plastic sand blowing to effectively remove adsorbates from the surface of the aluminized turbine blade layer, while also reducing the adverse effects on the aluminized layer thickness, blade size, and blade profile.

[0038] In one embodiment, in step S110, the preset spray angle is 45°±20°. This angle range allows the urea plastic sand to act on the surface of the aluminized turbine blade in a manner that combines tangential friction and normal impact, thereby ensuring the removal effect of adsorbents while reducing excessive impact on the thin aluminized layer. In practical applications, a basic spray angle can be determined first based on the nozzle installation position of the sandblasting equipment, the blade clamping state, and the direction of the blade surface to be treated. Then, fine adjustments can be made within the range of 45°±20° according to the surface curvature variations of different blade regions. This allows the urea plastic sand to form a more uniform sandblasting effect on the surface of the aluminized turbine blade and provides consistent angle conditions for subsequent spray distance simulation and pressure and time tests at this preset spray angle.

[0039] In one embodiment, S130, the orthogonal process test of urea-plastic sand blowing on the aluminized turbine blades includes: Multiple candidate sand blowing pressure values ​​and multiple candidate sand blowing time values ​​are set, and the candidate sand blowing pressure values ​​and candidate sand blowing time values ​​are combined to obtain multiple orthogonal experimental groups; In each orthogonal test group, the type of urea plastic sand, the preset spray distance and the preset spray angle were kept consistent, and the test blades were treated with urea plastic sand blowing according to the candidate blowing pressure value and candidate blowing time value in the corresponding orthogonal test group.

[0040] Specifically, the candidate blowing pressure value can be determined based on the adjustable pressure range of the blowing equipment, the spraying performance of the urea-plastic sand, and the tolerance of the aluminized layer. The candidate blowing time value can be determined based on the degree of adsorbent adhesion, the blade surface area, and the expected cleaning efficiency. Subsequently, the candidate blowing pressure and time values ​​are combined to form multiple orthogonal experimental groups. Each orthogonal experimental group corresponds to a set of blowing pressure and time combinations, used to evaluate the cleaning effect and damage risk of urea-plastic sand on the aluminized turbine blades under that combination. In each orthogonal experimental group, except for the candidate blowing pressure and time values, the type of urea-plastic sand, the preset spraying distance, and the preset spraying angle remain consistent. The purpose of this setting is to reduce the influence of other process factors on the experimental results, ensuring that the differences in results between the orthogonal experimental groups mainly stem from differences in blowing pressure and time, thus facilitating the comparison of the effects of different parameter combinations on adsorbent removal and aluminized layer protection.

[0041] In one embodiment, the candidate sandblasting pressure values ​​include 0.15 MPa, 0.2 MPa and 0.25 MPa, and the candidate sandblasting time values ​​include 10 s, 20 s, 30 s, 40 s, 60 s and 90 s.

[0042] In specific experiments, 0.15MPa, 0.2MPa, and 0.25MPa can be combined with 10s, 20s, 30s, 40s, 60s, and 90s, respectively, to obtain multiple combinations of blowing pressure and blowing time. Each combination corresponds to an orthogonal experimental group. The type of urea-plastic sand, the preset injection angle, and the preset injection distance remain consistent in each orthogonal experimental group; only the blowing pressure and blowing time values ​​are changed. This facilitates the evaluation of the impact of blowing pressure and blowing time on the cleaning effect and the risk of damage to the seepage layer.

[0043] After the sandblasting test, surface observation, fluorescence inspection, size detection, and diffusion layer thickness detection can be performed on the test blades under different combinations. If the adsorbent removal is insufficient or obvious fluorescence adsorption still exists under a certain combination, it indicates that the cleaning ability of that combination is insufficient. If the adsorbent removal effect is good under a certain combination, but the blade size changes significantly or the diffusion layer thickness is removed in large quantities, it indicates that there may be a risk of over-sandblasting under that combination. By comparing the above combinations of candidate sandblasting pressure values ​​and candidate sandblasting time values, the sandblasting pressure and sandblasting time suitable for the aluminized turbine blades to be treated can be screened.

[0044] In one embodiment, prior to S100, the aluminized turbine blades to be treated are subjected to aqueous ultrasonic cleaning and fluorescent inspection. When the aluminized turbine blade to be treated does not exhibit fluorescence adsorption due to surface adsorbents after ultrasonic cleaning with water-based agent, the aluminized turbine blade is determined to be a blade that does not require sandblasting treatment. If the aluminized turbine blades to be treated still exhibit fluorescence adsorption due to surface adsorbates after ultrasonic cleaning with an aqueous agent, then S100 shall be performed on the aluminized turbine blades to be treated.

[0045] Specifically, aqueous ultrasonic cleaning is mainly used to remove oil, loose particles, some carbon deposits, oxides, and other easily removable contaminants from the blade surface. By performing aqueous ultrasonic cleaning before sandblasting, the total amount of contaminants that need to be removed in subsequent urea plastic sand sandblasting can be reduced, and unnecessary sandblasting can be avoided on blades that already meet the requirements for fluorescence inspection. If the cleaned aluminized turbine blade does not exhibit fluorescence adsorption due to surface adsorbates, it indicates that the blade surface condition meets the requirements for subsequent defect detection, and the aluminized turbine blade can be determined as a blade that does not require sandblasting. If the cleaned aluminized turbine blade still exhibits fluorescence adsorption due to surface adsorbates, it indicates that conventional aqueous ultrasonic cleaning is insufficient to fully remove the adsorbates on the surface of the aluminized layer. These adsorbates easily form background interference in subsequent fluorescence inspection, affecting the determination of defects such as cracks. Therefore, this aluminized turbine blade is used as the blade to be treated, and S100 is executed, using urea plastic sand as the sandblasting medium, and the blade is sandblasted according to preset process parameters.

[0046] In one embodiment, the determination of preset process parameters further includes verifying the damage margin of preset sandblasting pressure and preset sandblasting time after S130. Damage margin verification includes: using urea plastic sand as the blowing medium, and performing control blowing treatment on the test blades according to the preset injection angle, preset injection distance and preset blowing pressure. The blowing time of the control blowing treatment is the product of the preset blowing time and the preset extension multiple, and the preset extension multiple is greater than 1. When the test blade after sandblasting treatment meets the requirements of continuous and intact seepage layer, no cracks, no peeling, and seepage layer removal amount not exceeding the preset seepage layer removal amount threshold, the preset sandblasting pressure and preset sandblasting time are determined as the process parameters that pass the damage margin verification.

[0047] Specifically, to confirm that the preset sandblasting pressure and preset sandblasting time have sufficient process safety margins, this embodiment also verifies the damage margin of the preset sandblasting pressure and preset sandblasting time. The damage margin verification is not directly used to treat the aluminized turbine blades to be treated, but is verified through test blades to determine whether urea plastic sand blowing will still not cause unacceptable damage to the aluminized layer when the sandblasting time is extended relative to the preset sandblasting time.

[0048] In the damage margin verification, the same urea-plastic sand as in S100 was used as the blowing medium, and the preset injection angle, preset injection distance, and preset blowing pressure were kept constant. Unlike S100, the blowing time in the control blowing treatment was not directly the preset blowing time, but rather the product of the preset blowing time and a preset extension factor. Since the preset extension factor is greater than 1, the blowing time in the control blowing treatment was longer than the preset blowing time used in the normal process. This method simulates situations that may occur in actual production, such as localized repeated blowing, excessively long operating times, or prolonged processing times due to heavy adsorbent adhesion, thereby evaluating whether the process parameters corresponding to the preset blowing pressure and preset blowing time have a damage margin.

[0049] In one specific embodiment, after determining the preset blowing pressure and preset blowing time, the test blades can be subjected to control blowing treatments at 2 times and 3 times the preset blowing time, respectively. That is, if the preset blowing time is T, then 2T and 3T are used as the blowing times for control blowing treatments, respectively. Under the condition of 2 times the blowing time, the influence of process parameters on the aluminized layer under a large operating margin can be verified; under the condition of 3 times the blowing time, it can be further verified whether the process parameters will still not cause discontinuity damage, cracks, or peeling of the aluminized layer under more stringent extended treatment conditions.

[0050] In specific experiments, when a control sandblasting treatment was performed at 2 and / or 3 times the preset sandblasting time, if the aluminized layer on the test blade remained continuous and intact, without cracks or peeling, and the amount of aluminized layer removed did not exceed the preset aluminized layer removal threshold, it can be concluded that the damage to the aluminized layer caused by the urea plastic sand sandblasting process is within an acceptable range. Therefore, when the aluminized turbine blades to be treated are subsequently subjected to S100 sandblasting treatment according to the preset sandblasting pressure and preset sandblasting time, the risk of excessive removal of the aluminized layer, crack formation, or peeling of the aluminized layer can be reduced while removing the adsorbed substances on the surface of the aluminized layer.

[0051] If, after control sandblasting treatment using a preset extension factor, the test blade exhibits any of the following: discontinuous diffusion layer, cracks, spalling, or diffusion layer removal exceeding a preset diffusion layer removal threshold, it indicates that the damage margin of the preset sandblasting pressure and time is insufficient. The candidate sandblasting pressure or time value can be readjusted, and orthogonal process experiments or damage margin verification can be performed again. This avoids directly applying high-risk process parameters to the aluminized turbine blades being treated.

[0052] In one embodiment, when the aluminized turbine blade to be processed is a hollow blade, a wax seal is used to prevent urea plastic sand from entering the inner cavity of the hollow blade before S100. Wax sealing protection methods include: Use high-temperature resistant aluminum foil tape to seal the vent holes on the surface of the hollow blades and leave wax injection holes; Preheat the sealed hollow blades; Molten wax is poured into the inner cavity of the hollow blade through the wax injection hole; After the molten wax poured into the inner cavity of the hollow blade cools and solidifies, the hollow blade is then subjected to S100. After S100 and before S300, the hollow blades are immersed in hot water to melt and flow out the wax inside the hollow blades.

[0053] Specifically, for hollow blades with film cooling holes, because the blade surface has multiple exhaust holes, film cooling holes, or channels communicating with the internal cavity, urea plastic sand may enter the hollow blade's internal cavity through these channels during the urea plastic sand blowing process. If the urea plastic sand that has entered the internal cavity cannot be removed in time, it may affect the flow rate of the film cooling holes or the unobstructed flow of the internal cooling channels. Therefore, before performing S100, a wax seal can be used to protect the hollow blades to reduce the possibility of urea plastic sand entering the blade's internal cavity.

[0054] When applying wax sealing protection, first use high-temperature resistant aluminum foil tape to seal the vent holes on the surface of the hollow blade. The high-temperature resistant aluminum foil tape maintains good adhesion and sealing stability during subsequent preheating and sandblasting processes, thus preventing urea plastic sand from entering the blade's inner cavity through the vent holes. Simultaneously, wax injection holes are pre-drilled on the hollow blade. These wax injection holes can be small holes on the upper end face of the blade or channels connecting to the inner cavity of the hollow blade to facilitate the injection of molten wax. By pre-drilling wax injection holes, a channel for molten wax to enter the inner cavity is still provided after sealing other vent holes.

[0055] The sealed hollow blade is preheated. Preheating reduces the temperature difference between the molten wax and the blade, allowing the molten wax to flow and fill more smoothly after being poured into the hollow blade cavity, minimizing problems such as rapid solidification of the molten wax, insufficient filling, or voids due to the low blade temperature. After preheating, molten wax is poured into the hollow blade cavity through the wax injection hole. The molten wax can be injected into the hollow blade cavity using a syringe, injection tube, or other injection tools, filling the space to be protected within the hollow blade cavity. After wax injection, the molten wax poured into the hollow blade cavity is allowed to cool and solidify. Cooling and solidification can occur naturally at room temperature or using controlled cooling methods as needed. After solidification, a solid protective body is formed inside the hollow blade cavity. This solid protective body can temporarily seal the blade cavity during urea plastic sand blowing, preventing or reducing the entry of urea plastic sand into the film pores and internal cooling channels.

[0056] After the molten wax cools and solidifies, the hollow blades undergo S100 treatment, which uses urea-plastic sand as the blowing medium and performs sandblasting according to preset process parameters. In this state, the inner cavity of the hollow blade is protected by solidified wax, so even if urea-plastic sand acts on the surface of the hollow blade during the sandblasting process, it is not easy for it to enter the inner cavity of the blade through the exhaust holes or air film pores.

[0057] After S100 and before S300, the hollow blades are immersed in hot water to melt and drain the wax inside the blade cavity. The hot water temperature can be determined based on the melting point of the wax and the tolerance conditions of the blade material, ensuring that the wax melts without affecting the blade body and the aluminized layer. During immersion, the hot water can fully contact the hollow blades, and the melted wax can be facilitated by appropriately changing the blade orientation or gently agitating the water.

[0058] After dewaxing, S300 is then performed to ultrasonically clean the aluminized turbine blades after residual sand removal. Ultrasonic cleaning can further remove residual wax, fine urea plastic sand particles, or other loose deposits from the surface and orifice area of ​​the hollow blades, restoring the hollow blades to a state suitable for subsequent inspection after wax sealing protection, sand blowing, and dewaxing.

[0059] In one embodiment, when the aluminized turbine blade to be processed is a hollow blade, a differential pressure protection method is used before S100 to prevent urea plastic sand from entering the inner cavity of the hollow blade. The differential pressure protection method includes: installing the aluminized turbine blade to be treated on a ventilated blade sandblasting fixture, and introducing compressed air into the inner cavity of the hollow blade through the ventilated blade sandblasting fixture, so that the compressed air is discharged outward along the air film holes of the hollow blade; wherein, the pressure of the compressed air is greater than the preset sandblasting pressure of the urea plastic sand.

[0060] Specifically, in the differential pressure protection method, the aluminized turbine blade to be treated is first installed in a ventilated blade sandblasting fixture. The ventilated blade sandblasting fixture is used to position and fix the hollow blade and communicates with the inner cavity of the hollow blade. The ventilated blade sandblasting fixture may include a blade positioning structure, a sealing structure, and an air intake structure. The blade positioning structure is used to maintain a stable posture of the hollow blade during the sandblasting process; the sealing structure is used to reduce compressed air leakage from the connection between the fixture and the blade; and the air intake structure is used to introduce compressed air into the inner cavity of the hollow blade.

[0061] After the hollow blade is installed into the ventilated blade blowing fixture, compressed air is introduced into the inner cavity of the hollow blade through the fixture. Once inside the hollow blade cavity, the compressed air is discharged outwards through the film membrane air holes, creating an outward airflow at the holes. This outward airflow direction is opposite to the direction in which urea plastic sand might enter the inner cavity through the film membrane air holes, thus effectively blocking the entry of urea plastic sand into the holes.

[0062] The pressure of the compressed air is greater than the preset blowing pressure of the urea plastic sand. By making the compressed air pressure inside the cavity higher than the blowing pressure of the external urea plastic sand, a cavity pressure can be formed inside the hollow blade, keeping the air film vents in an outward exhaust state. In this way, when the urea plastic sand is blown into the S100 cavity, even if the urea plastic sand is sprayed near the air film vents, it will be blocked by the compressed air discharged from the air film vents and will not easily enter the hollow blade cavity.

[0063] During the S100 sandblasting process, a ventilated blade sandblasting fixture continuously supplies compressed air into the inner cavity of the hollow blade, causing the film gas vents to continuously exhaust air outwards. The sandblasting nozzles perform sandblasting treatment on the surface of the hollow blade according to preset spray angle, preset spray distance, preset sandblasting pressure, and preset sandblasting time to remove adsorbed substances from the aluminized layer surface. Because the inner cavity of the hollow blade is under differential pressure protection, the probability of urea plastic sand entering the film gas vents and internal cooling channels is reduced.

[0064] After completing S100, the supply of compressed air to the hollow blade cavity can be stopped, and the hollow blade can be removed from the ventilated blade sand-blowing fixture. Then, S200 and S300 can be performed to clean residual sand and perform ultrasonic cleaning on the hollow blade. If the subsequent film gas flow test shows that the hollow blade flow rate meets the requirements, it indicates that the differential pressure protection effectively reduces the risk of urea plastic sand entering the cavity; if the flow rate decrease exceeds the preset difference, the hollow blade can be treated using a high-temperature sand removal method.

[0065] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A process for removing adsorbates from the surface of a high-temperature turbine blade permeate layer, characterized in that, Includes the following steps: S100 uses urea plastic sand as the blowing medium to blow aluminized turbine blades according to preset process parameters to remove adsorbents on the surface of the aluminized layer of the aluminized turbine blades. The preset process parameters include preset spray angle, preset spray distance, preset sandblasting pressure, and preset sandblasting time; S200 is used to clean residual sand from the aluminized turbine blades after sandblasting to remove the urea plastic sand remaining on the surface of the aluminized turbine blades. S300 is used for ultrasonic cleaning of aluminized turbine blades after residual sand removal. S400, fluorescent inspection of aluminized turbine blades after ultrasonic cleaning; When the aluminized turbine blade to be treated is a hollow blade, a film pore flow test is performed on the hollow blade before S100 and after S300 respectively; when the decrease in the film pore flow test value after S300 relative to the film pore flow test value before S100 exceeds a preset difference, the hollow blade is subjected to high-temperature desanding treatment. High-temperature sand removal treatment includes: placing the hollow blades in a heating box for heating, causing the urea plastic sand entering the inner cavity of the hollow blades to vaporize and / or pulverize; Compressed air is used to blow away the powdery residue inside the hollow blade.

2. The process for removing adsorbents from the surface of the high-temperature turbine blade diffusion layer according to claim 1, characterized in that: After high-temperature sand removal treatment, the hollow blades were tested again for film pore flow rate. If the decrease in the film pore flow rate test value compared to the previous film pore flow rate test value in S100 still exceeds the preset difference, the high-temperature desanding treatment and film pore flow rate test are repeated. When the value of the air film orifice flow test is qualified, proceed to step S400.

3. The process for removing adsorbents from the surface of the high-temperature turbine blade diffusion layer according to claim 1, characterized in that: The preset process parameters are determined through the following steps: S110, Determine the preset spray angle; S120, under the preset injection angle, a gas phase high-energy jet simulation model is established based on the surface structure of the aluminized turbine blade to be treated, and the surface roughness distribution and surface stress distribution of the aluminized turbine blade under multiple candidate injection distances are simulated using the gas phase high-energy jet simulation model, and the preset injection distance is determined based on the surface roughness distribution and surface stress distribution. S130, under the conditions of preset injection angle and preset injection distance, set multiple candidate sand blowing pressure values ​​and multiple candidate sand blowing time values, and use the candidate sand blowing pressure values ​​and candidate sand blowing time values ​​as test factors to conduct urea plastic sand blowing orthogonal process test on aluminized turbine blades; based on the adsorbent removal effect, fluorescence inspection results, size inspection results and diffusion layer thickness inspection results after the orthogonal process test, determine the preset sand blowing pressure and preset sand blowing time.

4. The process for removing adsorbents from the surface of the high-temperature turbine blade diffusion layer according to claim 3, characterized in that: In step S110, the preset spray angle is 45°±20°.

5. The process for removing adsorbents from the surface of the high-temperature turbine blade diffusion layer according to claim 3, characterized in that: In S130, the orthogonal process test of urea-plastic sand blowing on aluminized turbine blades includes: Multiple candidate sand blowing pressure values ​​and multiple candidate sand blowing time values ​​are set, and the candidate sand blowing pressure values ​​and candidate sand blowing time values ​​are combined to obtain multiple orthogonal experimental groups; In each orthogonal test group, the type of urea plastic sand, the preset spray distance and the preset spray angle were kept consistent, and the test blades were treated with urea plastic sand blowing according to the candidate blowing pressure value and candidate blowing time value in the corresponding orthogonal test group.

6. The process for removing adsorbents from the surface of the high-temperature turbine blade diffusion layer according to claim 5, characterized in that: The candidate sandblasting pressure values ​​include 0.15MPa, 0.2MPa and 0.25MPa, and the candidate sandblasting time values ​​include 10s, 20s, 30s, 40s, 60s and 90s.

7. The process for removing adsorbents from the surface of the high-temperature turbine blade diffusion layer according to claim 1, characterized in that: Before S100, the aluminized turbine blades were subjected to aqueous ultrasonic cleaning and fluorescent inspection. When the aluminized turbine blade does not exhibit fluorescence adsorption due to surface adsorbates after ultrasonic cleaning with water-based agent, the aluminized turbine blade is determined to be a blade that does not require sandblasting treatment. If the aluminized turbine blade still exhibits fluorescence adsorption due to surface adsorbates after ultrasonic cleaning with water-based agent, the aluminized turbine blade is designated as the aluminized turbine blade to be treated, and S100 is executed.

8. The process for removing adsorbents from the surface of the high-temperature turbine blade diffusion layer according to claim 3, characterized in that: The determination of preset process parameters also includes verifying the damage margin of preset sandblasting pressure and preset sandblasting time after S130. Damage margin verification includes: using urea plastic sand as the blowing medium, and performing control blowing treatment on the test blades according to the preset injection angle, preset injection distance and preset blowing pressure. The blowing time of the control blowing treatment is the product of the preset blowing time and the preset extension multiple, and the preset extension multiple is greater than 1. When the test blade after sandblasting treatment meets the requirements of continuous and intact seepage layer, no cracks, no peeling, and seepage layer removal amount not exceeding the preset seepage layer removal amount threshold, the preset sandblasting pressure and preset sandblasting time are determined as the process parameters that pass the damage margin verification.

9. The process for removing adsorbents from the surface of the high-temperature turbine blade diffusion layer according to claim 1, characterized in that: When the aluminized turbine blade to be treated is a hollow blade, a wax seal is used before S100 to prevent urea plastic sand from entering the inner cavity of the hollow blade. Wax sealing protection methods include: Use aluminum foil tape to seal the vent holes on the surface of the hollow blades and leave the wax filling holes in advance; Preheat the sealed hollow blades; Molten wax is poured into the inner cavity of the hollow blade through the wax injection hole; After the molten wax poured into the inner cavity of the hollow blade cools and solidifies, the hollow blade is then subjected to S100. After S100 and before S300, the hollow blades are immersed in hot water to melt and flow out the wax inside the hollow blades.

10. The process for removing adsorbents from the surface of the high-temperature turbine blade diffusion layer according to claim 1, characterized in that: When the aluminized turbine blade to be processed is a hollow blade, a differential pressure protection method is used before S100 to prevent urea plastic sand from entering the inner cavity of the hollow blade. The differential pressure protection method includes: installing the aluminized turbine blade to be treated on a ventilated blade sandblasting fixture, and introducing compressed air into the inner cavity of the hollow blade through the ventilated blade sandblasting fixture, so that the compressed air is discharged outward along the air film holes of the hollow blade; the pressure of the compressed air is greater than the preset sandblasting pressure of the urea plastic sand.

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